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  • 151.
    Fredriksson, Jan
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Sandberg, Mats
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    The effect of false ceiling on the cooling capacity of passive chilled beams2009Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 44, nr 7, s. 1426-1430Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Passive chilled beams are often used to provide cooling or additional cooling when the ventilation system cannot cope with the whole cooling load. The advantage of passive cooling is that it is a silent cooling. Often the chilled beams are installed above a false ceiling and thereby the room is subdivided into two compartments. From the chilled beam a plume is generated. Make-up air (return air) needs to flow into the upper compartment to substitute the airflow generated by the chilled beam. Therefore openings for this purpose are installed in the false ceiling. Small openings constitute a resistance to the flow and the locations of the openings affect the flow pattern. The overall performance was studied in a mock-up of a real office by changing both the size and position of the openings for the make-up air. A uniform heating source was arranged by covering the floor with a heating foil. The best location and size of the openings were explored by both recording the heat absorbed by the beam and the temperature in the room. Minimum temperature attained in the room is the signature of the most efficient cooling. To achieve efficient cooling with a uniform floor-based heating source, two conditions must be fulfilled: a) the return opening area must be at least equal to the horizontal area of the chilled beam; b) the return air openings must be located at the perimeter of the room. In general we can expect conditions a) and b) to be applicable irrespective of type of heat, but for point sources we could achieve the best cooling by placing the return air opening above the heat source.

  • 152.
    Friberg, Jonas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Konstruktion av lagerställ för trådprodukter2011Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Sandvik Materials Technology (SMT) ingår i den stora verkstadskoncernen Sandvik. SMT utvecklar, tillverkar och säljer rostfria och höglegerade specialmetaller, motståndsmaterial samt processystem. SMT tillverkar bland annat trådprodukter för flera olika ändamål.

    En viss del av det material som används i produktionsanläggningen för trådprodukter lagras på så kallade pikställage i ett inomhuslager. Bakgrunden till arbetet är att de befintliga lagerställagen är föråldrade och i dåligt skick. Dessa kan under olyckliga omständigheter utgöra en risk för personskada vid hantering av material. Nya, mer lämpade, lagerställage önskades.

    Den inledande kartläggningen av inomhuslagret och pikställagen visade på flera områden som kan förbättras. De befintliga pikställagen är dåligt anpassade för stora delar av trådmaterialen. Inomhuslagret är även överdimensionerat i förhållande till den lagringskapacitet som krävs. Utifrån faktainsamlingen under den inledande delen av arbetet skapades ett nytt layoutförslag till lagerlokalen. Förslaget som presenteras gör att ungefär hälften av den nuvarande golvytan som behövs till lagerställage kan frigöras.

    En ombyggnation av lagerställagen blev alltmer aktuellt på grund av att en svår brand i anknytning till lagerlokalen. I samband med reparationer och uppbyggnad av skadade och förstörda delar av produktionsanläggningen planerades att viss produktionsutrustning ska placeras i lagerlokalen.

    Ett konstruktionsförslag för ett lagerställage togs fram med hjälp av CAD-program, modeller och konstruktionsritningar skapades. Konstruktionsförslaget är ett kraftigt lagerställage som har en moduldesign för att underlätta montage och underhåll. De olika delarna av förslaget som skapades består till stor del av stålprofiler som bearbetats för att sedan monteras ihop med hjälp av skruvförband. Vid utformningen av infästningar som ingår i lagerställaget användes konstruktionsmetoder för balkinfästningar i stålbyggnader.

    Simuleringar med FEM (finita elementmetoden) genomfördes för att undersöka deformationer och spänningar som uppstår vid belastning enligt ett antal lastfall. Resultat från FEM-simuleringar kontrollerades mot de kravs som ställs i svensk standard för liknande typ av lagerställage.

    Konstruktionsförslaget jämfördes även med så kallade grenställage som finns på dagens marknad. Vad gäller priser på dessa så är de billigare än det presenterade konstruktionsförslaget. Grenställagen är dock inte anpassade för den typ av trådmaterial som ska lagras. Hanteringen av trådmaterialet ställer hårda krav på lagerställage samtidigt som skador på trådmaterial vill undvikas. Det konstruktionsförslag som presenteras är mer anpassade för trådmaterial än de befintliga pikställage som används i dagsläget.

  • 153.
    Frisk, Anders
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Simulering av solavskärmning och nattkyla för att minimera kylbehovet för en kontorsbyggnad i Forsmark2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Samhället idag är beroende av energi för att det ska fungera. Energi behövs för uppvärmning av byggnader när det är kallt eller kyla byggnader när det är varmt. Energi används för att driva belysning, apparater och transporter mm. Bostäder och lokaler står för 40 % av den totala slutliga energianvändningen och hälften av energin som bostäder använder går till uppvärmning.

    För att minska energianvändningen och stoppa den globala uppvärmningen är det viktigt att nya byggnader är energieffektiva. Målen som styr mot minskad energianvändning är EU:s 20/20/20- mål. Dessa mål ska nås senast 2020 och ska sänka utsläppen av växthusgaser med 20 %, sänka energiförbrukningen med 20 %, öka andelen förnybar energi till 20 % och höja andelen biobränsle inom transportsektorn till 10%. För att Sverige ska uppnå miljömålen har boverket tagit fram energikrav för fastigheter med målsättningen att minska energianvändningen inom bostadssektorn. Kraven gäller nya fastigheter och begränsar den energi som fastigheten får bruka till fastighetsenergi, uppvärmning, tappvarmvatten och kyla.

    Examensarbetet handlar om att utföra en simulering av nattkyla och solavskärmning för en kontorsbyggnad under förstudie. Simuleringar kommer även utföras för byggnadens energibehov, värmeeffektbehov och kylbehov. Programmet som har använts för simuleringen är IDA ICE V4.7. Simuleringarna visade att solavskärmningen minskade effekten för kyleffektbehovet med 4,8kW, en 13% minskning jämfört för en byggnaden utan solavskärmning. Både solavskärmningen och nattkylan visade sig vara effektiv för att minska kylenergibehovet för byggnaden. Totalt kan kylbehovet minskas med 84% för byggnaden vid givna förutsättningar. Energisimuleringen visade sig att byggnaden klarar de specifika energikrav som finns både för installerad uppvärmningseffekt och energianvändning.

  • 154.
    FU, YU
    Högskolan i Gävle, Akademin för teknik och miljö.
    Foreign market entry strategies: a case study for a Chinese pump manufacturer2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Economic globalization, regional economic cooperation and knowledge economy make a great impact on the development of the new century. The changes of international trade and investment reflect the variety of the world economy development; the world economic development, in turn, influences the international trade and investment in both quality and quantity (Feenstra, 1998). The international marketing has become an important trend in this modern society, global strategy has been put at the top of the agenda of many companies. And making development in the international market can also be a good solution for the companies to increase their competition (Mittelman, 1996). It is vital for those companies to deal with foreign market entry as a first step in accomplishing their global mission (Onkvisit & Shaw, 2004).  How to enter a foreign market is very important in this case, so the purpose of this work is therefore to research important factors on entering a foreign market. The theories, including environmental assessment before entry and foreign market entry strategies, are summarized by literature review and in order to make the theories applicable, a case study on a company inChinahas been done in this work as well. The methods used in this work include collecting processed data from literature review, gathering primary data by telephone interviews and through e-mails. SWOT analysis is used to assess targeted market for the case company. The case company is Shandong Shuanglun Group which is a famous pump manufacturer inChina; its targeted market that the company wants to enter is the Italian market. After SWOT analysis, the conclusion of this work indicated that opportunities of entry targeted market for the case company includes favorable tax policies and relevant laws, the threats in high context culture and terrorist activities should be paid attention to. The company has strengths in product but weaknesses in service, strategic alliance with one local pump manufacturer and exporting could be their market entry modes.

  • 155.
    Fältholm, Ylva
    et al.
    Högskolan i Gävle. Luleå University of Technology, Luleå, Sweden.
    Norberg, Cathrine
    Luleå University of Technology, Luleå, Sweden.
    Gender diversity and innovation in mining – a corpus-based discourse analysis2017Inngår i: International Journal of Gender and Entrepreneurship, ISSN 1756-6266, E-ISSN 1756-6274, Vol. 9, nr 4, s. 359-376Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose The purpose of this study is to gain increased knowledge about gender diversity and innovation in mining by analyzing how women are discursively represented in relation to these two concepts, and in doing so establish how diversity management is received and communicated in the industry. Design/methodology/approach The study is based on analysis of texts including references to gender diversity and innovation in mining found on the web. The tool used to retrieve the data has been WebCorpLive, a tool designed for linguistic analysis of web material. Findings Although increased female representation is communicated as a key component in the diversity management discourse, based on the idea that diversity increases innovation and creativity, closer analysis of texts on diversity and innovation in mining shows that what women are expected to contribute with has little explicit connection with innovation. Research limitations/implications The study contributes with increased knowledge about diversity management by providing an example of how it is received in a traditionally male-dominated industry. Practical implications Our findings indicate that for diversity management to have a real effect in mining, it needs to be based on gender equality and social justice motives, rather than on a business case rationale ? the principal motive today. To enable this change stereotypical gender patterns, as shown in this study, need to be made visible and problematized among policy makers, practitioners and actors on all levels of the industry. Originality/value The study contributes with new knowledge about gender in the mining industry previously not attended to by using a method which so far has been sparsely used in discourse analysis, although pointed out as promising.

  • 156.
    Galarraga, Maider
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Heat balance of a historical church- transmission losses2014Independent thesis Advanced level (degree of Master (One Year)), 40 poäng / 60 hpOppgave
    Abstract [en]

    The structure of old monumental churches differs a lot from contemporary buildings. The structural materials were wood, brick and stone. In order to construct high buildings with huge spans, thick massive walls and many massive columns were needed. Originally these buildings had no heating and for centuries the outdoor temperature determined the indoor climate. As churches are considered historical heritage buildings their renovation should be thoroughly studied.

     

                In this thesis the transmission losses of Hamrånge church will be analysed. Hence, the transmission trough walls and windows as well as the heat buffering of materials will be examined. In addition, the effect of possible reformation measurements will be concluded.

     

                Finally, this project belongs to a complete study of the church, were not only transmission losses are considered but also air infiltration losses and solar heat gain. That way, a comparison between them will be carried out in order to contribute to attain the objective of the project: possible restoration for church heating system with respect to preservation, energy requirements, thermal comfort and aesthetics.

  • 157.
    Gallego, Julio
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Mätsystemanalys för kontrollmätning av stiftshåldiameter på en borrkrona2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete har utförts på Sandvik Mining and Construction Tools AB (SMC) och hade som uppdrag att införa arbete med statistisk processtyrning (SPS) vid en produktionscell. Innan implementering av SPS tekniker krävs det en säkerställning av mätsystemets tillförlitlighet. Målet med arbetet är att genom en mätsystemanalys (MSA) utvärdera den befintliga mätmetodens duglighet och erbjuda berörd personal vid SMC en ny mätmetodsmodell om den befintliga mätmetoden fallerar.

    Metoden som användes för att utföra MSA var en fallstudie. Analysen genomfördes med hjälp av olika förbättringsarbetssätt inom Sex sigmas metodik som till exempel DMAIC-förbättringscykel och fiskbensdiagram. Underlagen för studien baserades på kvantitativa- och kvalitativa data. Insamling av kvantitativa data utfördes med hjälp av strukturerade observationer medan kvalitativa data samlades in med hjälp av en nulägesanalys, individuella intervjuer, benchmarking och litteraturstudie. Arbetet består av 3 analyser utförda på två olika mätsystem.

    Resultatet pekade på att de befintliga mätsystemen inte var tillförlitliga nog för att kunna användas i produktionen hos SMC. Mätsystem 1 (mätmaskinen) exkluderades från vidare analyser på grund av tidsbrist för att kunna genomföra förbättringar på det. Mätsystem 2 gick igenom en förbättringsfas där flera grundorsaker till variationer i processen analyserades och förbättrades. Dessvärre blev mätsystemet fortfarande odugligt för att användning i produktionen.

    Med hjälp av matematiska och statistiska beräkningar fastställdes det att mätmaskinen är det lämpligaste mätsystem att använda inom produktionen hos SMC. Det kan betyda att mätsystemets acceptans är beroende av mätinstrumentet.

  • 158.
    Gamage, Amila
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    CO2 Emission of Hotel Sector in Sri Lanka: A Case study & Scenario Analysis2014Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This research focused the CO2 emission and energy consumption pattern of Sri Lanka’s Hotel sector in both present and 2020 scenarios. It was proven from the literature survey that there was no study carried out to assess the current and future CO2 emission in Sri Lankan Hotel sector which is the government main focused area to develop within next 10 years of time. Also there is a long conversation in tourism sector from last few years and understood the importance of Sustainability of tourism business and identified the Green concept, Low carbon emission and less environmental impact are the key attributes to concern for the business sustainability.

    It was identified the CO2 emission in 2020 is 404,234 tonnes against the 121,458 tonnes of 2010 which is a huge impact to the environment because of expected growth of tourism sector. Also it was identified the CO2 emission per room in 2020 is 61.26 kg against the same 61.85 kg in 2010. This was slight change compared to the emission per room in 2010 but it will not considerably reduce the impact to the expected environmental pollution. The main energy consumption is from 5-star hotel category, which was contributed to 47% of total energy consumption even though this sector has contributed only 24% of total room capacity of the country in the present scenario of 2010, which was forecasted and identified the contribution to the total CO2 emission is 49.2% in 2020. This analyzing and modeling was done by using LEAP (Long Range Energy Alternative Planning System).

  • 159.
    Ghahremanian, Shahriar
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Near-Field Study of Multiple Interacting Jets: Confluent Jets2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with the near-field of confluent jets, which can be of interest in many engineering applications such as design of a ventilation supply device. The physical effect of interaction between multiple closely spaced jets is studied using experimental and numerical methods. The primary aim of this study is to explore a better understanding of flow and turbulence behavior of multiple interacting jets. The main goal is to gain an insight into the confluence of jets occurring in the near-field of multiple interacting jets.

    The array of multiple interacting jets is studied when they are placed on a flat and a curved surface. To obtain the boundary conditions at the nozzle exits of the confluent jets on a curved surface, the results of numerical prediction of a cylindrical air supply device using two turbulence models (realizable  and Reynolds stress model) are validated with hot-wire anemometry (HWA) near different nozzles discharge in the array. A single round jet is then studied to find the appropriate turbulence models for the prediction of the three-dimensional flow field and to gain an understanding of the effect of the boundary conditions predicted at the nozzle inlet. In comparison with HWA measurements, the turbulence models with low Reynolds correction ( −  and shear stress transport [SST]  − ) give reasonable flow predictions for the single round jet with the prescribed inlet boundary conditions, while the transition models ( −  and transition SST ) are unable to predict the flow in the turbulent region. The results of numerical prediction (low Reynolds SST model) using the prescribed inlet boundary conditions agree well with the HWA measurement in the nearfield of confluent jets on a curved surface, except in the merging region.

    Instantaneous velocity measurements are performed by laser Doppler anemometry (LDA) and particle image velocimetry (PIV) in two different configurations, a single row of parallel coplanar jets and an inline array of jets on a flat surface. The results of LDA and PIV are compared, which exhibit good agreement except near the nozzle exits.

    The streamwise velocity profile of the jets in the initial region shows a saddle back shape with attenuated turbulence in the core region and two off-centered narrow peaks. When confluent jets issue from an array of closely spaced nozzles, they may converge, merge, and combine after a certain distance downstream of the nozzle edge. The deflection plays a salient role for the multiple interacting jets (except in the single row configuration), where all the jets are converged towards the center of the array. The jet position, such as central, side and corner jets, significantly influences the development features of the jets, such as velocity decay and lateral displacement. The flow field of confluent jets exhibits asymmetrical distributions of Reynolds stresses around the axis of the jets and highly anisotropic turbulence. The velocity decays slower in the combined regio  of confluent jets than a single jet. Using the response surface methodology, the correlations between characteristic points (merging and combined points) and the statistically significant terms of the three design factors (inlet velocity, spacing between the nozzles and diameter of the nozzles) are determined for the single row of coplanar parallel jets. The computational parametric study of the single row configuration shows that spacing has the greatest impact on the near-field characteristics.

  • 160.
    Ghahremanian, Shahriar
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Janbakhsh, Setareh
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Construction and Evaluation of a Controlled Active Mass (CAM): A new cooling system design for increased thermal comfort using low exergy sources2007Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays, office buildings often have large temperature variations during the day and building envelope acts as an energy storing mass and damp these effects and so Offices need more cooling because of internal heat sources. But we know that cooling is more expensive than heating and it uses the very good quality of energy sources (exergy). Controlled Active Mass (CAM) is new approach to absorb radiant heating and acts as a passive cooling device. It has direct cooling effect and reduces the peak load. CAM is a new cooling system design with applying the low energy sources and operates at water temperature close to room temperature and increase the efficiency of heat pumps and other systems.

    In this project, we calculated the transient heat transfer analysis for CAM in a very well insulated test room with façade wall, Internal heat generators (such as Manikin, Computer simulator & lighting) and ventilation.

    Then Polished (shiny) CAM constructed from Aluminum sheets with 0.003 m thickness. It is cube shape with 0.6 m length. This size of CAM is according to 2.5 times larger than human body volume and initial water temperature assumed near half of human body temperature. Then in order to more radiation damping (absorption) by CAM, it painted black (also based on color analysis in heat transfer calculation).

    Some velocity and temperature measurement have been carried out on both polished CAM and black CAM, after visualization by smoke and Infrared Camera. And more cases tested to see the effect of façade wall, IHG’s and ventilation inlet temperature. Thermal comfort measurement also have been done for finding PMV, PPD and temperature equivalent for a seated person which is doing an office job with normal closing.

    At the end results discussed which includes the effect of CAM in room, differences between polished CAM and black CAM and effect of main heat sources on both CAM types (Polished / Black).

  • 161.
    Ghahremanian, Shahriar
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Department of Management and Engineering, Linköping University.
    Moshfegh, Bahram
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Department of Management and Engineering, Linköping University.
    A study on proximal region of low reynolds confluent jets: Part 1: Evaluation of turbulence models in prediction of inlet boundary conditions2014Inngår i: ASHRAE Transactions, 2014, nr PART 1, s. 256-270Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Conventional ventilation systems (mixing and displacement) produce low air quality in industrial premises. A new air supply system (confluent jets system) may improve the ventilation efficiency and the energy efficiency. When round jets issue from co-planar nozzles with enough spacing, they converge, merge, and combine at certain downstream distances, which are called confluent jets. In order to numerically predict confluent jets, it is crucial to provide inlet boundary conditions for these jets at the nozzles' exit. Numerical prediction of inlet boundary conditions of confluent jets was chosen due to two reasons: the difficulty of measurement at the nozzles' exit, and lack of information about the shape of the employed nozzles to make artificial inlet profiles. Numerical predictions by two turbulence models (Realizable k - ε and RSM) of the supply device producing the confluent jets was verified by hot-wire measurements at 0.26 d0 downstream of the nozzles' exit in both lateral and vertical direction. The verification was carried out for different nozzles in an array by measuring axial velocity and its turbulence intensity. The axial velocity profile at the nozzles exit has a saddle-back shape with two distinct off-centered overshoots. The convergence of the velocity profile shows the existence of Vena contracta phenomena. Low turbulence intensity at the central part of nozzles was found with narrow shear layer upstream of confluent jet flow. Differences of velocity components, turbulent kinetic energy (TKE), and turbulent dissipation rate (TDR) of the studied contraction nozzle were examined with a flow issuing from a typical long pipe. Reynolds number dependency in the studied range has been carried out and Re effects were observed on TKE but not on TDR. 

  • 162.
    Ghahremanian, Shahriar
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Department of Management and Engineering, Linköping University.
    Moshfegh, Bahram
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Department of Management and Engineering, Linköping University.
    Evaluation of RANS models in predicting low reynolds, free, turbulent round jet2014Inngår i: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 136, nr 1, artikkel-id 011201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to study the flow behavior of multiple jets, numerical prediction of the three-dimensional domain of round jets from the nozzle edge up to the turbulent region is essential. The previous numerical studies on the round jet are limited to either two-dimensional investigation with Reynolds-averaged Navier-Stokes (RANS) models or three-dimensional prediction with higher turbulence models such as large eddy simulation (LES) or direct numerical simulation (DNS). The present study tries to evaluate different RANS turbulence models in the three-dimensional simulation of the whole domain of an isothermal, low Re (Re = 2125, 3461, and 4555), free, turbulent round jet. For this evaluation the simulation results from two two-equation (low Re k-ε and low Re shear stress transport (SST) k-ω), a transition three-equation (k-kl-ω), and a transition four-equation (SST) eddy-viscosity turbulence models are compared with hot-wire anemometry measurements. Due to the importance of providing correct inlet boundary conditions, the inlet velocity profile, the turbulent kinetic energy (k), and its specific dissipation rate (ω) at the nozzle exit have been employed from an earlier verified numerical simulation. Two-equation RANS models with low Reynolds correction can predict the whole domain (initial, transition, and fully developed regions) of the round jet with prescribed inlet boundary conditions. The transition models could only reach to a good agreement with the measured mean axial velocities and its rms in the initial region. It worth mentioning that the round jet anomaly is still present in the turbulent region of the round jet predicted by the low Re k-ε. By comparing the k and the ω predicted by different turbulence models, the blending functions in the cross-diffusion term is found one of the reasons behind the more consistent prediction by the low Re SST k-ω. 

  • 163.
    Ghahremanian, Shahriar
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Moshfegh, Bahram
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Investigation in the near-field of a row of interacting jets2015Inngår i: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 137, nr 12, artikkel-id 121202Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Multiple interacting jets (confluent jets) are employed in many engineering applications, and the significant design factors must be investigated. Computational fluid dynamics (CFD) is used to numerically predict the flow field in the proximal region of a single row of round jets. The numerical results that are obtained when using the low Reynolds k-∈ are validated with the experimental data that are acquired by particle image velocimetry (PIV). PIV was used to measure mean velocity and turbulence properties in the proximal region of a row of six parallel coplanar round air jets with equidistant spacing at low Reynolds number (Re = 3290). The low Reynolds k-∈ underpredicts the streamwise velocity in the onset of the jets' decay. The characteristic points are determined for various regions between two neighboring jets. The comparison of the merging point (MP) and the combined point (CP) computed from measurements and simulations shows good agreement in the different regions between the jets. In this study, a computational parametric study is also conducted to determine the main effects of three design factors and the interactions between them on the flow field development using response surface method (RSM). The influences of the inlet velocity, the spacing between the nozzles, and the diameter of the nozzles on the locations of the characteristic points are presented in the form of correlations (regression equations). CFD is used to numerically predict the characteristic points for a set of required studies, for which the design values of the simulation cases are determined by the Box-Behnken method. The results indicate that the spacing between the nozzles has a major impact on the flow characteristics in the near-field region of multiple interacting jets. The RSM shows that the inlet velocity has a marginal effect on the merging and CPs. All of the square terms are removed from the response equations of MP, and only one two-way interaction term between inlet velocity and spacing remains in the regression model with a marginal effect. The square of the nozzle diameter contributes in the regression equations of CP in some regions between the jets.

  • 164.
    Ghahremanian, Shahriar
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energiteknik. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Moshfegh, Bahram
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energiteknik. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Numerical and experimental verification of initial, transitional and turbulent regions of free turbulent round jet2011Inngår i: 20th AIAA Computational Fluid Dynamics Conference 2011, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Three-dimensional simulation of the whole domain (initial, transition and fully developed regions) of round jet is essential in order to predict and to study the flow behavior of multiple jets (e.g. confluent jets). According to authors knowledge, numerical prediction of round jet with RANS models that has been presented by other researchers, are only in two-dimensional (axisymmetric) and mostly for the fully developed region. The inlet boundary conditions,  inlet velocity profile, turbulent kinetic energy and its dissipation rate at the diffuser exit has been governed from an earlier verified numerical simulation. In the present paper, results of three-dimensional modeling of isothermal, free, turbulent round jet with two two-equation (Low Re  and SST ), a transition three-equation ( ) and a transition four-equation (SST) eddy-viscosity turbulence models with resolved inlet profiles are compared and validated with hot-wire anemometry. This study shows that numerical simulation of round jet with SST  gives good agreement with measured mean longitudinal velocities, while transition models could only predict the initial region of round jet.

  • 165.
    Ghasemi, Milad
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Hammodi, Hassan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Moosavi Sigaroodi, Homan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Parallel-Powered Hybrid Cycle with Superheating “Partially” by Gas Turbine Exhaust2014Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    It is of great importance to acquire methods that has a sustainable solution for treatment and disposal of municipal solid waste (MSW). The volumes are constantly increasing and improper waste management, like open dumping and landfilling, causes environmental impacts such as groundwater contamination and greenhouse gas emissions. The rationalization of developing a sustainable solution implies in an improved way of utilizing waste resources as an energy source with highest possible efficiency. MSW incineration is by far the best available way to dispose the waste. One drawback of conventional MSW incineration plants is that when the energy recovery occurs in the steam power cycle configuration, the reachable efficiency is limited due to steam parameters. The corrosive problem limits the temperature of the superheated steam from the boiler which lowers the efficiency of the system. A suitable and relatively cheap option for improving the efficiency of the steam power cycle is the implementation of a hybrid dual-fuel cycle.

    This paper aims to assess the integration of an MSW incineration with a high quality fuel conversion device, in this case natural gas (NG) combustion cycle, in a hybrid cycle. The aforementioned hybrid dual-fuel configuration combines a gas turbine topping cycle (TC) and a steam turbine bottoming cycle (BC). The TC utilizes the high quality fuel NG, while the BC uses the lower quality fuel, MSW, and reaches a total power output of 50 MW.  Using a high-quality fuel in cogeneration can prove to be beneficial for improving and enhancing the overall plant profitability and efficiency while eliminating the corrosion problems with conventional MSW firing. The need for few interconnections between the different subunits in a parallel-fueled system allows for a wider range of operation modes and leaves room for service modes of the subunit. The hybrid dual-fuel cycle will be assessed for optimal cycle configuration and evaluated to how it compares to the sum of two separate single-fuel plants with optimal cycle configurations. Investigation of such aspects is a very important issue in order to be able to fully promote an implementation of hybrid combined cycle. The work presented herein also concentrates on investigating scenarios that include a full-load and part-load analysis in both condensing and combined heat and power (CHP) mode of operation.

    Through simulations and evaluation of obtained data, the results strengthens the fact that the electrical efficiency of hybrid configurations increases at least with 2% in condensing mode and 1,5% in CHP mode, comparing it to the sum of two separate single-fuel units of similar scale. The simulations show increased electrical efficiencies when running the BC in part-load and the TC in full load, with a higher NG to MSW ratio. The results also indicated that it is possible to extract more power output from the cycle by operating in CHP mode, due to more energy being utilized from the input fuel. 

  • 166.
    Gil, Arnaud
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Raffier, Alex
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Wallpaper drying solutions: Feasibility study of a low temperature drying process2008Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    The wallpaper company Duro Sweden AB, one of the most important Scandinavian

    wallpaper manufacturers, wants to decrease its energy use and costs and make its

    production more environmentally friendly. It implies changes in the key process energy

    use whom consists mainly by drying process using heat production from oil.

    The purpose of this project, studied by the consulting company Sweco Theorells AB,

    is to determine the feasibility of a change in the energy utilisation implemented to the

    most representative process to propose future solutions’ basis on the future energy

    question.

    The company use mainly two kind of energy, electricity with 1055MWh per year and

    oil with 1985MWh per year. The oil power consumption and cost represent respectively

    65% and 73% of the global part.

    Several proposed changes with better energy efficiency are presented : use of district

    heating as a heat source, Infrared Drying, combination, etc; but due to the important

    rebate make by the Swedish government on the oil price, they are not currently viable to

    achieve.

    But the constant rise of the oil price could be sooner a strong incentive to make these

    improvals, strongly environmentaly friendly and power consumption reducer,

    economicaly viable in the long term.

  • 167.
    Gomez, Adrian
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem. Bomhus Energi.
    Identification and evaluation of internal leakages of a BFB Boiler integrated within a pulp and paper mill.2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Alternative fuels like biomass have become really popular in the last decades as a substitute to fossil fuels. One of the most used technologies in Sweden for the obtention of the energy from the biomass is its direct combustion in a boiler. Bomhus Energi is a company with the purpose of creating steam and district heating for Billerudkorsnäs pulp and paper mill in Gävle and district heating for the city by operating a biomass BFB boiler. Despite being a quite new boiler, there are many sources of errors, losses and unnecessary costs. Between huge number of different losses that can happen in this kind of industrial boilers, the concern about internal leakages is not usually popular among plant designers and operators. This often leads to forget about them or not giving the importance that they could have.This study consists on, firstly, an analysis of different boiler equipment that have potential possibilities of internal leakages by mass and energy balances and by the tracking of possible mass losses. The second point of this thesis is to evaluate the cost of internal leakages that could have happen before, in order to be aware of how important they are. Additionally, measures are proposed in order to avoid or reduce the duration of the internal leakages, where the most common problem is the ignorance of their existence. This study focuses partially on the valve condition and maintenance. It is highly important to carry out valve maintenance procedures at least once per year during the general stop of the plant. Checking and verifying valve perfect conditions, can avoid a waste of a huge quantity of money just by replacing some internal elements that are possibly damaged due to the extreme working conditions. This small damages in valve can lead to a non-proper water tightening, which will be increasing its leakage over time. In the present paper, possible internal leakages through the valves belonging to the feedwater, steam drum, preheater and pressure vessel in general have been the principal aim. The key of this study was to take into account that biggest part of the draining system and valves that are supposed to be closed end in the Bottom blowdown tank. By then a deep study was done regarding this tank. The results show that there is a clear relationship between mass that is getting loss from feedwater tank and pressure vessel and the necessary cooling flow in the bottom blowdown tank. This means that if the cooling flow increases at the same rate as a possible leakage in mass and energy balance, there is an internal leakage somewhere in the system. The author proposes add an alarm to the DCS system in order to alert the plant operations of possible internal leakages. On the other hand, this paper also recommends to carry out a general valve maintenance per year and check which of them could be leaking, a general stop is the perfect time for carrying it out.In conclusion, the study finds that internal leakages can be even automatically detected if the system is provided with the necessary tools for it. The study concludes that internal leakages are not impossible to detect and their cost is non-negligible: the latest two internal leakages in the boiler, happened in the last two years, were from the feedwater draining system and from the steam drum heating loop with a total cost of 200,000 SEK (4240 SEK/day during 47 days) and 263,000 SEK (2120 SEK/day during 124 days) respectively. Additionally, days after the study, the plant general stop was carried out, finding that 12 valves were leaking due to internal damage. The cost of repairing the broken or damaged elements were almost negligible compared with the expected savings estimated in 2 Million SEK per year.

  • 168.
    Gomà Golanó, Pau
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Design of a carbon fibre rim for a fuel efficient competition vehicle2014Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    Motivated by the persistently pursued weight reductions in a vehicle projected for a fuel efficiency competition, this thesis deals with designing new and lighter rims for the vehicle. The aim of the thesis is to design the rims with a carbon-fibre reinforced polymer, a lightweight composite material. A profound study on this kind of material is also presented, since it could be useful for lighten, subsequently, other parts of the vehicle. The thesis is based on a review of literature to acquire a theoretical framework. The design process and its validation is supported by finite element analyses.

    The preliminary design starts with a closed V profile, which appears to be a viable and adequate option for the application. The rim is divided into three parts, the contour and two sidewalls. By modelling and simulating the rim, the profile of each part is optimized and information about the stress´s state is acquired. Therefore the layered structure for the different parts are defined by taking the optimum proportions of the fibre's orientations into account. The parts are then simulated making use of a layered element which in the end validates the design.

    The reserve factors found are 1,67 for the contour and around 1,5 for the sidewalls, which indicates the good adjustment of the design between safety and performance. On the other hand, an estimation for the weight reduction is calculated, which achieves values around 17% on the better cases. With further work on the manufacturing process the design can in the end offer a reasonable saving of weight.

  • 169.
    Granat, Mikael
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö.
    Nelson, Alexander
    Högskolan i Gävle, Akademin för teknik och miljö.
    Etableringskriterier: för lagerhållande verksamhet2011Independent thesis Basic level (degree of Bachelor), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    The purpose of this thesis is to identify the most important establishment criteria for companies whointend to do a new establishment. There are differences between regions regarding attraction on startup.Some regions have few new businesses while others continuously expanded its activities in variousfields. The biggest focus on the thesis is the Gävle- Borlänge region where MellansvenskaHandelskammaren is active.Mellansvenska Handelskammaren saw a need for the assignment after the magazine ”IntelligentLogistik” ranked the Gävle region at 15:th place and Falun/Borlänge at 20:th place in the list over thetop 25 best logistics locations in Sweden. This made them wonder what could be made to develop intoa better area with more amenities and a better place in the ranking of the magazine. As a foundation tothe future development of the region this thesis has been written.The method we used is part a literature review and part a survey sent to different companies indifferent regions. The answers to the surveys was then compiled and compared with the literature tofind the most important criteria. The participation of the survey was lower then what we hoped for,however the responses aligned with the earlier observations of the literature review.The group has made an overview of some of the most successful regions and their available assets,such as roads, railway, port, aviation, businesses, establishment opportunities, training and skills andnetworks in the region. A more detailed review where also made of the Gävle- Borlänge region andthis was used to descried the strengths and weaknesses of the region. There are good opportunities inthe region to develop into an attractive area of establishment, a project to link Gävle and Oslo via anew road under the name E16 may come to provide a significant benefit at a regional level. Thisrelated to the expansion of the East Coasts largest container port can help to make Gävle an importanthub in the region.To be able to choose a place of establishment for companies we have after concluded literature reviewand analysis of survey responses been able to make a list of the most important criteria. With these thegroup has made a simple decision model. Companies who know their most important criteria can usethe model when they compare different locations.

  • 170.
    Grip, Katarina
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för industriell ekonomi.
    Pålsson, Jennifer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för industriell ekonomi.
    Hur lagerhanteringssystem och artikelidentifiering kan bidra till logistisk effektivitet: En fallstudie på Nefab i Runemo2009Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Warehouses are a key aspect of modern supply chains and play a vital role in the success or failure of businesses today. Figures from the USA indicate that the capital- and operating costs of warehouses represent about 22 % of a company’s logistics costs while figures from Europe indicate 25 % (Baker & Canessa, 2009). Because warehousing is such an important function within a company, the authors chose to focus on this in their thesis. The purpose of this thesis has been to examine the significance of a Warehouse Management System (WMS) and item identification with attention to logistic efficiency. With this as a starting point, the thesis also intends to examine the needs and possibilities with a WMS and some sort of item identification at a specific company and also present suggestions of how to move forward with this type of work.

  • 171.
    Gruvman, Joakim
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för industriell ekonomi, industridesign och maskinteknik, Industriell ekonomi.
    Andersson, Johan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för industriell ekonomi, industridesign och maskinteknik, Industriell ekonomi.
    Produktionsrelaterad förändring för ett bättre logistiskt flöde med mänsklig hänsyn: En fallstudie på PEPAB Produktionspartner AB2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Background: The business world is in constant change, which means that businesses must be able to adapt to these changes and constantly improve. The research field on how businesses should achieve a smart material supply is small, which emphasizes the importance of studying how a company can change its production layout to improve its internal logistics.

    Purpose: The purpose of this study is to increase the understanding of the production layout's importance for the material supply and the human aspect in production-related change work.

    Method: The study has used an abductive, exploratory approach to answer the purpose and the research questions. This means that studies of theories were done in parallel with studies of the empirical material at the case company PEPAB Produktionspartner AB. Theories from the literature and the empirical data have been analyzed and discussed in order to draw conclusions.

    Findings: The results are a description of the current internal material flow of four representative components and a description of employees´ attitude to change. By mapping the material flow, logistics flow factors and human related factors have been discovered. 

    Theoretical contribution: When changing the production starting from the logistic factors waiting, unnecessary inventory, unnecessary manufacturing, defects, unnecessary transportations and improperly designed production layout a better logistical flow and better material supply can be achieved. Combining this with a well-planned preparatory work with related training can make a successful change. 

    Practical contribution: This study contributes practically with a new production layout that enables a better logistical flow. It also emphasizes the importance of a well-thought-out and wellplanned preparatory work to maintain the staff´s sense of participation.

  • 172.
    Gustafsson, Dennis
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Comparing air quality in a training facility: What effects do air balancing have for carbon dioxide reduction?2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    The link between a good indoor climate and environmental impacts e.g. global warming and different pollution in the air is something that are important today and will certainly become more important in the future with increased energy prices and new laws.

    Too keep the indoor air quality within limits is it important to have a good and competitive ventilationsystem.

    The ventilations function is mainly to supply fresh air and to remove polluted air from the room. It’s important that the ventilation system works as it should so that the indoor air quality is as good as possible. The lack of good ventilation can create several symptoms such as headaches, nausea, fatigue, poor concentration etc.

    In Sweden are ventilation control mandatory for every newly produced building and this control are repetitive usually every 3-6 years for some types of buildings.

     

    The foundation of this thesis is from a previous degree project performed by a master’s student in 2013 named Ander Barroeta with supervision of Magnus Mattsson and Taghi Karimipanah.

    The thesis was to improve and design a ventilation system in two rooms at a training facility named Friskis & Svettis in Gävle so that the CO2 level did not exceed 1000 ppm.

     

    In this thesis was the main goal to do similar measurements as the previous thesis and compare the results to see what difference air balancing has done to the ventilation system. Field measurements were performed at the training facility were the focus was on carbon dioxide but also on other parameters such as temperature, humidity and air velocity so that air exchange rate could be calculated. With these parameters can evaluations be made to see if air balancing of the ventilation system made any difference in indoor air quality.    

     

    During measurements in one of the training rooms where spinning is exercised was carbon dioxide levels up to 3300 ppm measured which is above the recommended indoor limit at 1000 ppm. If that room should be design to not exceed 1000 ppm must the air exchange rate increase from 6.3 h-1 to 35.1 h-1.

  • 173.
    Gustafsson, Mattias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Pyrolys för värmeproduktion: Biokol den primära biprodukten2013Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Pyrolys innebär att exempelvis biobränsle hettas upp i syrefattig miljö för att bilda pyrolysgas och kol. Pyrolysgasen kan brännas för att producera värme med låga utsläpp och kolet har en mängd användningsområden; jordförbättringsmedel, fodertillskott, filtermaterial, kolfastläggning, energibärare, ståltillverkning m.m. Om krav på bränsle och användningsområde för kolet uppfylls kan kolet certifieras som biokol. Syftet med den här rapporten är att utreda om pyrolystekniken är ett hållbart, tekniskt och ekonomiskt alternativ till pellets- och flisförbränning för värmeproduktion. Målet är att förmedla pyrolysens tekniska och ekonomiska förutsättningar, såväl positiva som negativa. Rapporten är baserad på en kombination av litteraturstudier, djupintervjuer, besök vid anläggningar och referensgruppsamtal.

     

    Pyrolys har använts i tusentals år för att producera kol. I Amazonas upptäcktes landområden med en sammalagd yta större än Storbritannien i vilka jorden var kolsvart. Denna svarta jord, terra preta, är berikad med kol och har därmed blivit mycket bördigare än omgivande, ursprunglig jord. I Sverige framställdes kol för att tillgodose metallindustrin med bland annat produktionsmaterial och bränsle. Till skillnad från pellets- och flisförbränning kan pyrolystekniken använda en stor mängd olika bränslen så länge de uppfyller krav på energidensitet och fukthalt. Marknaden för biokol växer i bl.a. Tyskland men är ännu liten i Sverige. De leverantörer av pyrolysanläggningar som besökts i denna rapport, Pyreg och Carbon Terra, gör anläggningar med syfte att producera biokol. Pyreg har utvecklat en process med skruvreaktor och integrerad pyrolysgasbrännare för att t.o.m. kunna använda avloppsslam som bränsle. Carbon Terras process är enkel och robust med fokus att producera mycket kol.

     

    Pyrolysteknikens styrkor är flexibiliteten att välja olika typer av bränslen, låga utsläpp, liten negativ miljöpåverkan och kolets olika användningsområden. Ser man till svagheterna är de marknadsrelaterade; outvecklad svensk marknad och okunskap om kolets användningsområden. Dessutom gör pyrolysanläggningarnas statiska effektuttag att de är mindre flexibla än pellets- och flispannor. I en tid då klimatförändringarna letar akuta lösningar medför kolfastläggning och biokol som jordförbättringsmedel stora möjligheter tillsammans med omvandling av pyrolysgas till fordonsbränsle. Dock är den befintliga pellets- och flisförbränningen väletablerad som uppvärmningsteknik, vilket kan utgöra ett hot mot pyrolysteknikens intåg på marknaden. Avsaknaden av regelverk pga. kompetensbrist kan också försvåra för etablering av pyrolysanläggningar.

     

    Slutsatsen i denna rapport är att pyrolystekniken är ett bra alternativ till konventionell pellets- och flisförbränning om man kan hantera att värmeproduktinen är statisk och att man beaktar kolets värde. Värmeproduktion från pyrolysgas ger lägre utsläpp av bland annat CO, NOx och stoftpartiklar än pellets- och flisförbränning och om kolet används för kolfastläggning är möjligheten till globala klimateffekter betydande. Det som starkast påverkar den ekonomiska kalkylen är kostnaden för bränslet och intäkten på kolet. För att gardera sig mot den outvecklade biokolmarkanden i Sverige har kalkylerna i denna rapport baserats på försäljning av biokol som jordförbättringsmedel, vilket ger låga intäkter jämfört med andra användningsområden. Styrkan i att valet av bränsle är flexibelt gör det möjligt att ha en bränslekostnad på noll om materialet annars ses som avfall. Marknaden för kol i Sverige är outvecklad vilket kräver ett aktivt arbete från de som ger sig in branschen, men om utvecklingen följer den i Tyskland ser de ekonomiska förutsättningarna starka ut.

  • 174.
    Gustafsson, Mattias
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Thygesen, Richard
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Karlsson, Björn
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Ödlund, Louise
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Rev-Changes in Primary Energy Use and CO2 Emissions: An Impact Assessment for a Building with Focus on the Swedish Proposal for Nearly Zero Energy Buildings2017Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, nr 7, artikkel-id 978Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the European Union's Energy Performance of Buildings Directive, the energy efficiency goal for buildings is set in terms of primary energy use. In the proposal from the National Board of Housing, Building, and Planning, for nearly zero energy buildings in Sweden, the use of primary energy is expressed as a primary energy number calculated with given primary energy factors. In this article, a multi-dwelling building is simulated and the difference in the primary energy number is investigated when the building uses heat from district heating systems or from heat pumps, alone or combined with solar thermal or solar photovoltaic systems. It is also investigated how the global CO2 emissions are influenced by the different energy system combinations and with different fuels used. It is concluded that the calculated primary energy number is lower for heat pump systems, but the global CO2 emissions are lowest when district heating uses mostly biofuels and is combined with solar PV systems. The difference is up to 140 tonnes/year. If the aim with the Swedish building code is to decrease the global CO2 emissions then the ratio between the primary energy factors for electricity and heat should be larger than three and considerably higher than today.

  • 175.
    Haartman, Robin von
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Industriell ekonomi. Högskolan i Gävle, Centrum för logistik och innovativ produktion.
    The Challenge of being both Cost Efficient and Responsive: Analysing the Supply Chain Design of Ericsson, the Telecom Equipment Maker2010Inngår i: Proceedings of APMS 2010 - International Conference on Advances in Production Management Systems, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Literature suggests that supply chains should be designed based on the characteristics of products, including their technological maturity and the predictability of demand. The advantages of doing so are indisputable, but may be more difficult to achieve in practice. The aim of this paper is to, based on a single case study, analyse how a leading technology-based company solves the problems of conflicting supply chain demands. The company sells multiple products with varying degrees of technical maturity and predictability of demand. The study finds that technological maturity is driving a change towards a more efficient supply chain. The efficient supply chain is, however, not suitable for all products. The case company's solution is a dual-speed supply chain: a responsive one when demand is uncertain and an efficient one for standard products with predictable demand. The paper concludes that the supply chain will by necessity be a compromise as well as segmented based on the characteristics of the company's many products.

  • 176.
    Haghshenas, Samira
    et al.
    School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Sajadi, Behrang
    School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Multi-Objective Optimization of Impinging Jet Ventilation Systems: Taguchi Based CFD Method2018Inngår i: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 11, nr 6, s. 1207-1214Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a Taguchi method-based approach that can optimize the operating performance of impinging jet ventilation (IJV) systems with limited computational fluid dynamics (CFD) simulation results. The Taguchi optimization calculation finds the best operating design for the weighted overall objective function as a presenter of the multi-objective function problem. The method is used to optimize the operating characteristics of an IJV system considering the factors of supply air temperature, level of the return air vent and percentage of the air exhausted through the ceiling to achieve an overall best performance of thermal comfort, indoor air quality (IAQ) and system energy performance as the objective functions. The study indicates the contribution percentage for each factor in each objective function. The level of the return air vent, the supply air temperature, and the percentage of air exhausted through the ceiling have a contribution of 35.8%, 28.5%, and 35.8% in the objective functions, respectively. Based on the results, the best performance of the IJV system happens when the inlet air temperature is 18 °C, the height of the return air vent is 2 m above the floor, and the percentage of air exhausted through the ceiling is 22.5%.

  • 177.
    Hagström, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö.
    Utredning gällande avgradning av bandsågade stålrör2012Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Ett vanligt problem inom stålbranschen är att avlägsna grader från kapade stålrör ochstänger. En metod för detta är avgradning med hjälp av ett ändlöst slipband. SandvikMaterial Technology (SMT) tillämpar denna metod i Rörverk 50 i Sandviken.Slipmaskinens benämning är fingeravgradare. Vid avgradning roterar röret på ettvarvtalsstyrt roterställ varvid fingeravgradaren slipar bort rörets grader.Rören har en varierande grad av krokighet vilket leder till problem. Hela rörets periferiavgradas inte då det tappar kontakten med slipbandet och slipkrafterna blir ibland så storaatt slipbandet börjar slira på drivhjulet och går av. Avgradningshuvudet är den del islipanordningen som slipbandet löper runt och slipar rörets kant. Idag är den fastpositionerad och kan inte följa rörets rörelser som uppkommer. Arbetes syfte är attomkonstruerad avgradningshuvudet så att problemen elimineras.Olika konstruktionskoncept arbetades fram för att skapa rörelse hos avgradningshuvudet.Att konstruera avgradningshuvudet med ett vridcentrum för att skapa en rotationsrörelseblev det koncept som utvecklades.Ritningsunderlag erhölls över den nuvarande konstruktionen. Detta utnyttjades iAutoCAD Mechanical som är ett program för att skapa konstruktionsritningar i tvådimensioner. Genom att mäta och fastställa kraftriktningar beräknades krafterna sompåverkade avgradningshuvudet vid avgradning. Det gav underlag för att hittavridcentrumets placering för att uppnå det uppsatta kravet på slipkraft. Inventor är ettCAD-program som användes till att konstruera och skapa en tre dimensionell modell överden nya konstruktionen.Arbetet resulterade i konstruktionslösning med en vridaxel placerat påavgradningshuvudet. Genom en rotationsrörelse hos avgradningshuvudet följs röretskastningar och fullstädig avgradning sker med ökad slipbandslivslängd.Då den teoretiska utredningen inte alltid stämmer överens med verklighetenkonstruerades lösningen justeringsmöjligheter. På så sätt kan man öka eller minskarotationen hos avgradningshuvudet och slipkraften kan enkelt justeras vid behov.

  • 178.
    Halling, Bengt
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för industriell ekonomi, industridesign och maskinteknik, Industriell ekonomi. Högskolan i Gävle, Centrum för logistik och innovativ produktion. Division of Ergonomics, Royal Institute of Technology, KTH.
    Lyckström, Martin
    Scania CV AB, Södertälje, Sweden.
    Wijk, Katarina
    Högskolan i Gävle, Akademin för hälsa och arbetsliv, Avdelningen för arbetshälsovetenskap och psykologi, Arbetshälsovetenskap. Högskolan i Gävle, Centrum för belastningsskadeforskning. Centre for Research and Development, Region Gävleborg, Gävle, Sweden; Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden .
    Application of a sense of coherence-based leadership for productivity and health at Scania2019Inngår i: International Journal of Human Factors and Ergonomics, ISSN 2045-7804, E-ISSN 2045-7812, Vol. 6, nr 2, s. 179-194Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose was to explore if sense of coherence (SOC) theory can be used in human factors ergonomics (HFE) practice as a leadership approach to decrease the rate of sick leave and rehabilitation cases and increase work attendance among assembly personnel without impeding productivity. Via three studies carried out at the Swedish truck manufacturer Scania, we investigated the company's key performance indicators and documented meetings with managers during the intervention. The results show that SOC can be used in HFE practice and that productivity, quality and attendance at work increased, while rehabilitation cases decreased. Our conclusion is that a health promotion approach among managers is essential in a lean organisation that aims to reduce waste in the company and optimise human capability and thereby productivity. SOC theory can support the creation of workplaces that are high performing and healthy, starting with concerns for the people creating the output.

  • 179.
    Halling, Bengt
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Industriell ekonomi. Högskolan i Gävle, Centrum för logistik och innovativ produktion.
    Renström, Jonas
    Lean and the implementation process: managers perspective on change2011Inngår i: Det nya arbetslivet, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction and aims: Research has shown that view on Lean production differs both between researchers and practitioners and that there is no uniform definition of the concept (Emiliani 2006; Pettersen 2009). Furthermore, the perspective on Lean production as toolbox or philosophy, sometimes expressed as Lean thinking, influences the Lean implementation. Implementation of Lean can be seen as a project or an initiation of an ongoing developmental process where learning is taking place (Rother 2010). The purpose of this paper is to survey managers´s wiew of lean in terms of “toolbox Lean” or Lean thinking and their view of the implementation process in terms of a project with a time limit or as an initiation of an ongoing developmental process. The intention is to increase understanding about the relationship betweenhow Lean production is defined and implemented.

    Method: This paper is based on a case study at a Swedish manufacturing company aiming tobecome a company working with a business system based on Lean principles. The study has a multilevel, vertical, perspective covering five hierarchical management levels in the organization, from president of the company to first line managers at the shop floor. Data was collected through individual semi structured interviews with 14 managers at different organizational levels.

    Findings and reflection: The view on Lean has, according to managers, evolved at all management levels within the organization during the implementation. From a starting point were Lean was perceived as a set of tools by most, it has, as the managers increased their knowledge evolved into a view that is more complex and also includes behavioral and cultural issues. This would indicate that even if the starting point of an implementation of Lean is Lean tool focused it may over time come to include issues of management protocol addressing cultural development, coaching and communication as learning regarding the organizational needs take place. The interviews showed that managers on different hierarchical levels of the organization believed there to be differences in view regarding Lean within the organization. We however found the view on Lean to be quite similar at all management levels, described as a customer focused; standardized way of working that is continuously improved by keeping a process focus. The impression of there being differences in view regarding Lean is most likely caused by a lack of dialogue between organizational levels within the organization. Varying competence levels regarding Lean and thereby varying ways of working within the organization may create a lack of support between production and support functions. Health and health promotion are seen as important factors at the production unit that was studied.

    Research limitations: Organizational size and only partial coverage of the organization may limit the results validity to the parts of the organization that was researched and to larger organizations.

    Value: This paper provides insights regarding the learning process connected to a Lean implementation and that alterations of perspectives and needs may take place during such a process.

    Keywords: Lean production; Lean management; Lean implementation

    Paper type: Case study

  • 180.
    Hallkvist, Jonas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Förundersökning av möjligheten till modifiering av kylvattenintag: Undersökning av möjligheten till modifierat kylvattenintag vid Forsmarks kärnkraftsanläggning2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Elproduktion är en viktig del i dagens samhälle och hur man producerar elen har blivit en viktig fråga som diskuteras flitigt i Sverige och i omvärlden. I Sverige har elanvändningen och elproduktionen varit i närmaste oförändrad sedan 90-talet. Elanvändningen i Sverige är ca 140 TWh per år och drygt 40 % av detta produceras av kärnkraften. Detta medför att kärnkraften är en viktig del av den Svenska elproduktionen. Kärnkrafts-bolagen som äger kärnkraftverken i Sverige letar alltid efter sätt för att förbättra säkerheten på sina anläggningar samt att genomföra verkningsgradsförbättringar som minskar bränsleanvändningen. Det här arbetet inriktar sig på att öka produktionsförmågan genom att genomföra en verkningsgradsförbättring. Rapporten använder sig av en kvantitativmetod och behandlar vilka förutsättningar samt lösningar det finns till att sänka kylvattentemperaturen vid kärnkraftsanläggningen i Forsmark. Arbetet begränsar sig till att endast ge en överblick för vilka lösningar som finns. Ingen av lösningarna undersökas på djupet med undantag på mammutpumpar. Forsmark kärnkraftsanläggning består utav tre stycken reaktorer och använder tillsammans ca 145 m3/s kylvatten för att kyla ner ångan i turbinkondensatorerna. Att sänka temperaturen på kylvattnet med en grad innebär en verkningsgradsförbättring på 0,444 % vilket är utrett i rapporten. En sådan förbättring innebär att Forsmarks reaktor 3 ökar sin nettoeffekt med 5,25 MW. Att sänka kylvattentemperaturen kan göras på många sätt och i denna rapport ansågs det vara relevant att undersöka lösningar som lyfter upp bottenvatten eller blandar om vattnet ifrån olika nivåer i havet. De lösningarna som undersöktes var mammutpumpar, luftridå en vägg längst ytan, utgrävning av kylvattenkanal, förlängning av existerande kanal, djupvattenintag och strömbildare på botten. Den lösning som ansågs vara den mest attraktiva lösningen var luftridå och det var på grund utav att dess fördelar var många och dess nackdelar inte var alltför stora. De slutsatser som görs i denna rapport kan användas i andra reaktorer runtom i världen som har liknande förutsättningar.

  • 181.
    Hang, Jian
    et al.
    University of Hong Kong.
    Li, Yuguo
    University of Hong Kong.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Byggvetenskap - installationsteknik.
    Claesson, Leif
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, BMG Labbet.
    Wind Conditions and Ventilation in high rise long Street Models2010Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 45, nr 6, s. 1353-1365Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We regarded high-rise cities as obstacles and channels to wind. We first studied wind conditions and ventilations in idealized high-rise long street models experimentally and numerically with a constant street width (W = 30 mm), variable street heights (H = 2 W, 2.5W, 3W, 4W), variable street lengths (L = 47.4W, 79W. 333W, 667W) and a parallel approaching wind. The flow rates penetrating into windward entries are a little larger than the reference flow rate in the far upstream free flow through the same area with windward entries in all models. The stream-wise velocity decreases along the street as some air leaves upwardly across street roofs. Near the leeward entry, there is a downward flow which brings some air into the street and results in an accelerating process. In the neighborhood scale long streets (L = 47.4W and 79W), wind in taller streets is stronger and the ventilation is better than a lower one. For the city scale long streets (L = 333W and 667W), a constant flow region exists where the vertical velocity is zero and the stream-wise velocity remains constant. In such regions, turbulent fluctuations across the street roof are more important to air exchange than vertical mean flows. In a taller street, the process to establish the constant flow conditions is longer and the normalized balanced horizontal flow rate is smaller than those in a lower street. In the city scale long streets, the turbulence exchange rate can be 5-10 times greater than the mean flow rate. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

  • 182.
    Hang, Jian
    et al.
    Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Byggvetenskap - installationsteknik.
    Li, Yugo
    Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
    Claesson, Leif
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, BMG Labbet.
    Flow mechanisms and flow capacity in idealized long-street models2010Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 45, nr 4, s. 1042-1053Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is an open question whether a street network of a city has a certain flow capacity characterizing the flow that can pass through the street network. It s our hypothesis that at least the simple street network has a certain flow capacity. With the purpose of exploring this we studied numerically and experimentally the flow capacity in some idealized long-street models continuously lined with buildings and exposed to a parallel approaching wind. The height of all the models is the same (H = 69 mm). Three groups of models were studied: models with the same uniform street width (W = H) but different lengths (L = 21.7H, 43.5H, 72.5H); models with the same length (L = 43.5H) but different uniform width (W = H, 2H, 4H); and models with a change of width at half distance, L/2. In the last of the three cases, the width of the upstream half was always the same (W1 = H), but there was a wider (W2 = 1.25H, 1.5H, 2H) or narrower (W2 = 0.75H, 0.5H) downstream half. We normalized flow rates by a reference flow rate equal to the flow rate through an opening far upstream with the same area as the windward entry. The normalized flow rate through the windward entry was about 1.0 in all cases. For a sufficiently long-street models, a flow balance is established, creating a fully developed region with a constant horizontal flow (flow capacity) and zero vertical mean velocity. The street length does not affect the flow capacity but as expected the width of the street affects the flow capacity.

  • 183.
    Hang, Jian
    et al.
    Department of Atmospheric Sciences, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China.
    Wang, Qun
    Department of Atmospheric Sciences, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China .
    Chen, Xieyuan
    Department of Atmospheric Sciences, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China .
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Zhu, Wei
    Department of Atmospheric Sciences, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China .
    Buccolieri, Riccardo
    Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, University of Salento, Lecce, Italy.
    Di Sabatino, Silvana
    Department of Physics and Astronomy, University of Bologna, Bologna, Italy .
    City breathability in medium density urban-like geometries evaluated through the pollutant transport rate and the net escape velocity2015Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 94, nr P1, s. 166-182, artikkel-id 4213Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper investigates pollutant removal at pedestrian level in urban canopy layer (UCL) models of medium packing density (λ<inf>p</inf> = λ<inf>f</inf> = 0.25) using computational fluid dynamics (CFD) simulations. Urban size, building height variations, wind direction and uniform wall heating are investigated. The standard and RNG k-ε turbulence models, validated against wind tunnel data, are used. The contribution of mean flows and turbulent diffusion in removing pollutants at pedestrian level is quantified by three indicators: the net escape velocity (NEV), the pollutant transport rate (PTR) across UCL boundaries and their contribution ratios (CR).Results show that under parallel approaching wind, after a wind-adjustment region, a fully-developed region develops. Longer urban models attain smaller NEV due to pollutant accumulation. Specifically, for street-scale models (~100 m), most pollutants are removed out across leeward street openings and the dilution by horizontal mean flows contributes mostly to NEV. For neighbourhood-scale models (~1 km), both horizontal mean flows and turbulent diffusion contribute more to NEV than vertical mean flows which instead produce significant pollutant re-entry across street roofs. In contrast to uniform height, building height variations increase the contribution of vertical mean flows, but only slightly influence NEV. Finally, flow conditions with parallel wind and uniform wall heating attain larger NEV than oblique wind and isothermal condition.The paper proves that by analysing the values of the three indicators it is possible to form maps of urban breathability according to prevailing wind conditions and known urban morphology that can be of easy use for planning purposes. 

  • 184.
    Hanna, Hanibal
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik.
    Konstruktionsförslag på vattensystem till Scanias tillsatsbroms2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Målet med examensarbetet har varit att ta fram ett fungerande förslag på befintligt vattensystem mellan motor och retarder, som är billigt, monteringsbart, har låg vikt och lång livslängd i fordon. Retarder är en hjälpbroms och har som främsta uppgift att minska slitage på de ordinarie bromsarna.

    För att lösa detta gjordes först en nulägesbeskrivning där kylvattenröret kartlades. Därefter intervjuades Scania personalen på Retarder och det resonerades kring tidigare konstruktioner gjorda på området.

    De teorier som användes var monteringsanpassad konstruktion (DFA), tillverkningsanpassad konstruktion (DFM), miljöanpassad konstruktion (DFE), feleffektanalys (FMEA) och Scania produktions system (SPS).

    För att säkerställa vilken typ av material och tillverkningsmetod som ska användas i konstruktionen gjordes ett "out of the box" tänkande. Informationen som framkom pekade på att dimensionen borde optimeras, det betydliga materialet ändras och att fästena på kylvattenröret borde elimineras. Detta för att erhåll en billigare, lättare och mer monteringsvänligare konstruktion.

    Konstruktionsförslaget är ett kylvattenrör med fästen som är av bockad plåt och som monteras på gummirör för att dämpa vibrationerna. Här har jag ersatt de svetsade fästena med monterbara fästen som håller kylvattenröret på plats. Vidare har godstjockleken på kylvattenröret optimerats från 2 mm till 1,5 mm och jag har behållit det befintliga materialet SS-EN 1010216, tryckkärlsstål, då både aluminium och plast inte höll vid de vibrationer som uppkom i fordonet. Dessutom har fästena, som håller upp hela konstruktionen av kylvattenröret mot växellådan, omkonstruerats så att det passar det nya konstruktionen. Dessa fästen monteras på växelhuset med två stycken M10 skruvar i varje fäste.

    Simuleringar med finita elementmetoden (FEM) genomfördes för att undersöka deformationer och spänningar som uppstod när kylvätskan passerade genom kylvattenröret och då vibrationer uppstod från motorn, pumpen, hjulen eller vägunderlagen. Resultat från analyser med FEM tydde på att de största påkänningarna fanns på de rundfästen som håller upp kylvattenröret. Den högsta statiska spänningen på dessa fästen är 75 MPa med en sträckgräns på 500MPa. Denna anses vara låg och betraktas inte som kritisk.

    Vid den dynamiska analysen resulterade detta i att egenfrekvens uppkom vid 162 Hz som är över Scanias kritiska intervall, 150 Hz. För att säkerställa att konstruktionen är hållbar bör en prototyp tillverkas och testas.

    Förslaget presenterades för både chefen och montörerna på monteringsområdet och de var positiv inställda till förslaget av en rad olika anledningar så som lättare montering, kortare monteringstider, ergonomisk montering, kvalitetssäkrad montering samt förmonteringsbar. Dessutom kan bemanningen minimeras till följd av de korta monteringstiderna.

  • 185.
    Hansson, Andreas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, Maskinteknik.
    Reducering av icke värdeskapande aktiviteter vid tillverkning av träemballage2018Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Emballagefabriken tillverkar förpackningslösningar i form av trä- och plywoodlådor. Låg lönsamhet råder på företagets manuella monteringsavdelning på grund av lång genomloppstid vid tillverkning av produkten Plywoodlådan. Tillverkningen sker i fyra steg och börjar vid sågavdelningen följt av tryckeriet sedan cnc-avdelningen och till sist monteringen. Syftet med arbete var att reducera de icke värdeskapande aktiviteterna som uppstod i produktionsflödet.

    För att få en överblick av nuläget genomfördes en materialflödesanalys följt av en förstudie, som identifierade vilka aktiviteter som utfördes på respektive avdelning. Med detta som bakgrund genomfördes kvantitativa tidsstudier av aktiviteterna parallellt med kvalitativa observationer. Slutligen klassificerades samtliga aktiviteter med hjälp av produktionspersonal och produktionschefen.

    Tidsstudierna resulterade i en kartläggning av de icke värdeskapande aktiviteterna, som sedan analyserades. Slutligen togs förbättringsförslag fram som företaget kan implementera.

    Slutsatsen av arbetet visade att det fanns potential att reducera, och i vissa fall eliminera de icke värdeskapande aktiviteterna.

  • 186.
    Hasan, Farhan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik. University of Gävle.
    Possibilities of Geothermal Energy and its Competitiveness  with Other Energy Sources2014Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Geothermal Energy is one of the common talks at present. It has the potential to run long term and can provide base-load energy, at the same time it helps to reduce the greenhouse gas emissions. It is found almost everywhere on earth. The resources of geothermal energy range from shallow ground to hot water or hot rock, which can be found few kilometers below the surface and even deeper to magma where the temperature is extremely high. Since its discovery from the ancient times, many technologies have been developed to understand or use geothermal energy properly. 

    This report is based on literature survey of geothermal energy compared to other energy sources in terms of construction, supply energy and the advantage-disadvantage of the system. From this study it has been found that geothermal power plant does not need external fuel to operate, that’s why the price of geothermal energy does not go up like oil and gas, in USA the cost of geothermal electricity ranges from $0.06 to $0.10 per kilowatt-hour and besides it is one of the most clean, reliable and renewable energy source, which is environment friendly and cheaper than other energy sources.

  • 187.
    He, Qiao
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Trading Oil Futures2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Oil is an important energy source and a necessary industrial raw material. Every country’s economic growth and the daily life of its people are dependent on this energy form.

    Historically, the oil prices have varied significantly on the world market. This led to at least two oil crises when prices increased in a very fast pace. In order to reduce such rapid fluctuations, oil was introduced at so called commodity exchanges. At such trading places oil could be traded openly for future delivery and hence the market was aware of price changes in advance. A commodity exchange sells special contracts in the form of so called “futures”. In fact there are many different contracts, each exchange has its own set of them covering for a number of different oil types. This thesis deals with these contracts and how they are traded.

  • 188.
    Hikkaduwa Vithanage, Ajith
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    DESIGN AND PERFORMANCE ANALYSIS OF PITCHED-PLATE VERTICAL AXIS WIND TURBINE FOR DOMESTIC POWER GENERATION2012Independent thesis Advanced level (degree of Master (Two Years)), 80 poäng / 120 hpOppgave
    Abstract [en]

    Wind energy is identified a promising energy resource in Sri Lanka. Therefore, it is important to use proper technologies for efficient energy capturing in order to minimize cost of energy. Small scale wind turbines are usually installed in constricted places (particularly in urban areas) where wind flow is turbulent and difficult to predict. Savonious type vertical axis wind turbines are important due to several reasons such as good response to turbulent winds, high initial torque, low cost, low noise, less maintenance.In this study, a modified flat plate type Savonius wind rotor was proposed to cost effectively harness wind energy in constricted places. Generally, vertical axis wind turbines (VAWT) are less efficient than horizontal axis wind turbines, one reason behind this issue is wind force difference between the 2 sides of the axis is small and due to this reason torque is small and power generation capacity is less.A prototype of the proposed VAWT was fabricated and the performance was determined by acquiring experimental data. Artificial wind blow which was generated by a huge fan was used to measure rotational speed and torque characteristics at varying wind speeds. Data were collected with 1-second sampling time and a data acquisition system was developed under this study. In the proposed design one side of the turbine blades are facing the wind direction in order to capture maximum force while other side is edging the blades to have minimum opposite torque. With this concept it is expected to maximize the torque of the axis and generate more power. A sort of a passive pitch mechanism is therefore utilized in order to save energy and simplify the system. Turbine blades are simple flat plates and it eliminates usage of complex aero foils. Due to the simplicity of this design it would be possible to use this turbine for domestic electricity generation at affordable costs.Nowadays, net metering systems are being promoted in Sri Lanka and it would be beneficial to introduce low cost VAWT which operates at low winds as well as turbulent wind conditions. Based on typical household hourly load profile, viability of proposed vertical axis wind turbine was evaluated by considering rural and urban wind regimes in Sri Lanka. The costs of wind energy at two selected locations were determined in the context of net metering.

  • 189.
    Hildebertsson, Andrea
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för industriell ekonomi, industridesign och maskinteknik.
    Ericsson, Kajsa
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för industriell ekonomi, industridesign och maskinteknik.
    Affärssystem – Utmaningar och framgångsfaktorer för en framgångsrik implementeringsprocess: En multipel fallstudie för små- till medelstora företag verksamma i naturstensbranschen2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Enterprise resource planning system (ERP system) is a standardized support system that aims to support the various functions of a company. Companies have different conditions for a successful implementation process due to the complexity of the ERP system. Implementation of ERP systems is also considered to be particularly difficult in small- to medium sized enterprises (SME) because the process is depending on resources. The natural stone industry is unique because of the natural material that require great adaptation and selection. Only about 20% of the material that is mined from the bedrock can be used for further production. SMEs and the natural stone industry have been dedicated to a little attention in research when it comes to implementation of ERP systems. Therefore, two knowledge gaps are identified where one gap represents a lack of literature on ERP systems for SMEs and the other represents the natural stone industry's unexplored conditions and challenges regarding the implementation of ERP systems. The purpose of this work is therefore to identify critical success factors as well as challenges small companies operating in the natural stone industry possess in order to implement an ERP system and how these companies can avoid a time-consuming process with high costs.

    To realize the purpose a survey was sent out to companies operating in the natural stone industry and are members of the Swedish Stone Industry Association. Thenceforth four interviews have been conducted with three companies who are members of the Swedish Stone Industry Association and a consultant working to implement ERP systems was interviewed. The theory is chosen based on the purpose and has been collected from scientific articles, literature and websites explaining key concepts for the work. Based on the findings, a model has been created to represent a cross-industry approach to achieve a successful process for ERP system implementation. The model aims to demonstrate an approach which is to create an awareness of any challenges that may arise. Challenges such as material characteristics, lack of leadership and lack of a holistic perspective. Based on these challenges, companies should then focus on success factors such as user attitudes for ERP, the use of project teams and a parallel test system to generate a successful implementation process.

  • 190.
    Hillbom, Christoffer
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Lans, Theres
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad.
    Integrerade ledningssystem: Drivkrafter, möjligheter och hinder2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The world is changing and the business context is no exception. One of the clearest tendencies is a tougher business climate with harder competition due to increased international trade and the expansion of the e-business. At the same time the customers are becoming more sophisticated and demanding. The last decades have also meant that tougher and more frequent demands are being aimed at the businesses from a wider variety of stakeholders; demands regarding how environmental issues, social responsibilities and business ethics should be dealt with. All of the above have driven companies towards implementation of different management systems to be able to cope with the demands as well as to ensure that these issues are being dealt with in an efficient and effective manner. The result is that there might be quite a few management systems that have to be handled, usually a time consuming and bureaucratic task. Theory in the field suggests that an integration of the different management systems is logical and profitable as well as beneficial in many other aspects. Some of the benefits that could be gained due to the holistic approach that the integrated management system (IMS) provides are an alignment of goals and strategies as well as elimination of duplications and sub-optimizations. The IMS will also provide an opportunity for companies to strive towards sustainable development in a balanced manner. Despite this not many companies have intentionally sought to integrate their management systems. Researchers within the field note that there is a lack of empirical data to support the theories regarding how companies act when integrating their management systems, knowledge that might provide insights why integration and IMSs is not more widespread.Hence it is interesting as well as theoretical motivated to further study this area, especially as IMSs might be an aid on the companies’ journey towards sustainable development, a highly important issue. This qualitative multiple case study aims to contribute with knowledge regarding how Swedish companies have handled the issue of IMS, more specific, what driving forces, opportunities and hindrances they have experienced associated with IMS. This, as the knowledge about Swedish firms is limited. The research questions are answered through interviews with managers responsible for the management systems. The findings suggest that companies with more than one management system integrates them to some degree, however not always intentionally, and that it might be a lack of clear motives, driving forces and stakeholder demands that limits further or full integration. The outcome is that integration primarily becomes a coordination of existing management systems with purpose to reduce bureaucracy and redundancies.

  • 191.
    Hillman, Karl
    Institutionen för energi och miljö, Miljösystemanalys, Chalmers Tekniska Högskola, Göteborg.
    Environmental Assessment and Strategic Technology Choice: The Case of Renewable Transport Fuels2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The scale of the required changes is huge, and time is limited if we are to avoid the most severe effects of climate change. To reduce greenhouse gas emissions from road transport, several fuels and electricity originating from renewable energy sources have been proposed, all of them in different stages of development and with various and shifting environmental impacts. This thesis aims at increasing the usefulness of environmental assessments of emerging technologies as a basis for strategic technology choice. Recommendations for the design and interpretation of such assessments are presented, with a special focus on life cycle assessment (LCA) methodology. A long time perspective, the possibility of system change, and the inclusion of socio–technical change processes allows for the revision of methodological assumptions normally made in LCA of current products. To guide the selection of technologies, there is need for assessment both of technology and of interventions. For the assessment of technology, an attributional approach is applied. Paper I discusses and tests the feasible futures and future performance to be considered in attributional LCAs. The results indicate that the environmental impact attributable to a number of selected fuels, as well as the ranking of them, largely depend on assumptions regarding background systems and by-product use. For the assessment of interventions, a consequential approach is applied. Extensive studies of socio–technical change processes contribute insight into relevant cause–effect chains that can be included in environmental assessments of emerging technologies. A comparison between the Swedish and the Dutch innovation systems for renewable fuels reveals the unfolding of dynamics influenced by shared background factors (Paper II). An investigation of the Swedish history of alternative fuels is used in developing a framework for analysing interaction between emerging technological systems (Paper III). Insights into socio–technical change processes are then used to elaborate scenarios for the future development of renewable fuels in Sweden resulting from current policy choices (Paper IV). In a final paper (Paper V), historical and future cause–effect chains are taken into account in a consequential LCA of ethanol of varying origins in Sweden for the 1990–2020 period. It is concluded that for emerging technologies in an early stage of development, the contribution of an intervention to system change may be more important than the direct change in environmental impact. Finally, it is suggested that all aspects of socio–technical change and the resulting environmental impact may not have to be included in quantitative environmental assessments, such as LCA. ‘Environmental assessment’ could very well include a group of parallel studies that illuminate different cause–effect chains resulting in changed environmental impact, and that are part of a society-wide learning process.

  • 192.
    Hillman, Karl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Teknisk miljövetenskap.
    Governance of Innovation for Sustainable Transport: Biofuels in Sweden 1990-20102011Rapport (Annet vitenskapelig)
  • 193.
    Hillman, Karl
    Institutionen för energi och miljö, Miljösystemanalys ; Göteborgs miljövetenskapliga centrum (GMV).
    LCA and Strategic Choice of Biofuels2007Inngår i: LCA of Energy, Energy in LCA - SETAC Europe 14th LCA Case Studies Symposium, 3-4 December 2007, Göteborg, Sweden - Extended abstracts, 2007, s. 91-94Konferansepaper (Annet vitenskapelig)
  • 194.
    Hillman, Karl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöteknik.
    Materialåtervinning och klimatnytta: Hur räknar återvinningsaktörer i Sverige?2013Rapport (Annet vitenskapelig)
    Abstract [sv]

    Syftet med den här studien är att sammanställa hur aktörer verksamma i återvinningsbranschen i Sverige tar fram siffror på, och kommunicerar klimatnyttan vid återvinning av olika material, samt att undersöka hur väl de använda metoderna överensstämmer med vetenskapliga studier. Resultaten visar att flera stora aktörer inom branschen kommunicerar klimatnytta på likvärdiga sätt, i syftet att visa på ”den klimatnytta som återvinningen redan idag medför och vilken potential som finns att öka återvinningens bidrag till en minskad klimatpåverkan”. Detta innebär bland annat att aktörerna har för avsikt att vara både tillbakablickande och framåtblickande, samt att företag inte försöker jämföra sig med varandra med utgångspunkt i klimatnytta.

    Det tillgängliga underlaget och hur det används för beräkningar och kommunikation av klimatnytta visar sig ha flera brister som är signifikativa för miljöbedömningar. I huvudsak handlar dessa om att man kombinerar siffror från studier med olika antaganden vad gäller tidsperspektiv, geografisk täckning och val av växthusgaser, vilket innebär att resultaten inte blir rättvisande för något ändamål, och att man i princip inte kan dra några slutsatser från materialet. Samtidigt finns det gott om studier som rätt hanterade kan komma till användning för de syften de är framtagna för.

    I rapporten framhålls tre viktiga aspekter att förbättra vid beräkning och kommunikation av klimatnyttan med återvinning, samt vid användning av resultaten. För det första handlar klimatnytta inte bara om koldioxid, och miljönytta handlar inte bara om växthusgaser. Beräkningar av andra typer av utsläpp kan visa på ytterligare fördelar och eventuella nackdelar med återvinning. För det andra bör metodval och antaganden vara kopplade till studiens syfte, samt vara konsekventa, för att ge rättvisande och jämförbara resultat. För det tredje bör resultaten från olika studier endast användas för det syfte de är avsedda för, alternativt bearbetas för att kunna användas i andra sammanhang.

    Eftersom samtliga aktörer inom återvinningsbranschen i Sverige verkar ha liknande syften med sin kommunikation av klimatnyttan med materialåtervinning, och då tillgängligt dataunderlag inte ger något utrymme för att jämföra företag med varandra identifieras följande möjligheter för det fortsatta arbetet.

    1. Först och främst kan man inom branschen stämma av och eventuellt enas om vilka olika syften man vill uppnå med att beräkna klimatnytta.
    2. Därefter kan man gå vidare och arbeta tillsammans för att komma tillrätta med de brister som finns i underlaget, samt i hur det används. En möjlighet är att anlita en expert för att välja ut, bearbeta och komplettera det underlag som finns, så att det kan användas för de syften man vill uppnå. Branschen kan sedan försöka komma överens om gemensamma siffror, samt om hur de bör kommuniceras på lämpligt sätt.
    3. En framtida möjlighet inom området kan också vara att utveckla gemensamma riktlinjer för hur man ska ta fram och kommunicera företagsspecifika siffror på klimatnytta, i syfte att möjliggöra jämförelser mellan olika företag.
  • 195.
    Hillman, Karl
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Teknisk miljövetenskap.
    Nilsson, Måns
    Stockholm Environment Institute.
    Rickne, Annika
    University of Gothenburg.
    Magnusson, Thomas
    Linköping University.
    Fostering sustainable technologies: A framework for analysing the governance of innovation systems2011Inngår i: Science and Public Policy, ISSN 0302-3427, E-ISSN 1471-5430, Vol. 38, nr 5, s. 403-415Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development and diffusion of technological innovations need governing in order to contribute to societal goals related to sustainability. Yet, there are few systematic studies mapping out what types of governance are deployed and how they influence the development and diffusion of sustainable technological innovations. This paper develops a framework for analysing the role of governance in innovation systems aimed towards sustainability. The framework is based on the literatures on governance, technological innovation systems and socio-technical transitions. We foresee empirical studies based on the framework that may serve as a needed input into governance processes. © Beech Tree Publishing 2011.

  • 196.
    Hillman, Karl
    et al.
    , Institute for Management of Innovation and Technology (IMIT) and University of Gothenburg, Sweden.
    Nilsson, Måns
    Stockholm Environment Institute (SEI), Sweden.
    Rickne, Annika
    University of Gothenburg and Institute for Management of Innovation and Technology (IMIT), Sweden.
    Magnusson, Thomas
    Institute for Management of Innovation and Technology (IMIT) and Linköping University, Sweden.
    Framework for analysing the governance of innovation systems for sustainable technology2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Fostering sustainable technologies –a framework for analysing the governance of innovation systemsKarl Hillman, Post-doc researcher, Institute for Management of Innovation and Technology (IMIT) and University of Gothenburg,SwedenMåns Nilsson, Associate professor, Stockholm Environment Institute (SEI), SwedenAnnika Rickne*, Associate professor, University of Gothenburg and Institute for Management of Innovation and Technology (IMIT), SwedenThomas Magnusson, Assistantprofessor, Institute for Management of Innovation and Technology (IMIT) and Linköping University, SwedenAbstractThere is an ever-growing recognition among policy-makers, industries and analysts that the development and diffusion of technological innovations need governing in order to contribute to societal goals related to sustainability, such as climate change mitigation and resource efficiency. Yet, little is known about how different types of governance influence innovation processes, and what may be effective governance arrangements to pursue to influence the development and diffusion of sustainable technological innovations. This paper develops a framework for the analysis of governance arrangements aimed at fostering more sustainable technological innovations. The framework addresses important debates in governance and innovation research. First, it addresses a critical gap in the literature on technological innovation systems (TISs) which is the connection between governance arrangements and the functionality of the TIS. Second, it contextualizes this connection in relation to the multi-level perspective (MLP) to transitions, assuming that governance arrangements influence in different ways the functionality of the TIS depending on the structure, stability and positioning of the TIS in relation to the regime. Third, it develops a comprehensive heuristic to examine the prevalence, role and effectiveness of various modes of governance, departing from a simple typology of "who governs", "how do they govern", and "what isgoverned".The framework prompts a temporal causal analysis of predominantly qualitative nature.

  • 197.
    Hillman, Karl
    et al.
    Institute for Management of Innovation and Technology (IMIT).
    Nilsson, Måns
    Rickne, Annika
    Magnusson, Thomas
    Governance in technological innovation systems: biofuels and hybrid vehicles in Sweden2011Konferansepaper (Annet vitenskapelig)
  • 198.
    Hillman, Karl
    et al.
    Environmental Systems Analysis, Department of Energy and Environment, Chalmers University of Technology, Göteborg, Sweden.
    Sandén, Björn A.
    Environmental Systems Analysis, Department of Energy and Environment, Chalmers University of Technology, Göteborg, Sweden.
    Exploring technology paths: The development of alternative transport fuels in Sweden 2007–20202008Inngår i: Technological forecasting & social change, ISSN 0040-1625, E-ISSN 1873-5509, Vol. 75, nr 8, s. 1279-1302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By using socio-technical scenarios, we investigate how present policy choices may affect the development of alternative transport fuels in Sweden. One important choice for policy lies in the balance between general tax exemptions stimulating the market for alternative fuels, and funding of research and development more directly promoting new technology. The implications of this choice are illustrated with four diverging development paths until 2020. In the market-oriented scenarios, we illustrate consequences of breaking the dominance of entrenched technologies and demonstrating a growing market potential for alternatives, but also the risks with a large focus on first generation renewable fuels. In the technology-oriented scenarios, we point out the value of keeping variety among niches in this stage of the transition. In conclusion, if policy is implemented without taking the dynamic forces within the system into account, there is a risk that any measure leads the system into a dead end. But if policy strives to balance the development in different parts of the technological system while making use of various prevailing forces of change, a multitude of different efforts can contribute to the development of a more sustainable transport system.

  • 199.
    Hillman, Karl
    et al.
    Institutionen för energi och miljö, Miljösystemanalys.
    Sandén, Björn A.
    Institutionen för energi och miljö, Miljösystemanalys.
    Time and scale in Life Cycle Assessment: the case of fuel choice in the transport sector2008Inngår i: International Journal of Alternative Propulsion, ISSN 1471-0234, E-ISSN 1741-8011, Vol. 2, nr 1, s. 1-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Life Cycle Assessments (LCA, including Well-to-Wheel studies) that are to support decisions that strive to change large technical systems need to consider time and scale related factors, which are given little attention in standard LCA procedures. Here, we address three issues and provide examples from the case of alternative fuels. First, shifting time frame gives room for technical development that should affect not only the choice of performance data, but perhaps also the functional unit and the selection of technologies under study. Secondly, background systems, such as heat and power production, change over time and increased production volumes of the alternative fuel change the transport system that is used to produce transport fuel. We show that such changes have consequences not only for Greenhouse Gas (GHG) emissions from each fuel-chain, but also for the ranking order of, e.g. Rapeseed Methyl Esther (RME) and ethanol in terms of GHG emissions. Finally, different types of feedstock are available in different quantities and different by-product markets vary in size. Key markets for RME by-products in EU correspond to an RME production that covers about 3% of transport fuel demand. Consequently, GHG emissions that are allocated to the fuel should change with the scale of adoption

  • 200.
    Hillman, Karl
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Teknisk miljövetenskap.
    Suurs, Roald
    TNO.
    Hekkert, Marko
    Utrecht University.
    Sandén, Björn
    Chalmers University of Technology.
    Cumulative causation in biofuels development: a critical comparison of the Netherlands and Sweden2011Inngår i: The Dynamics of Sustainable Innovation Journeys / [ed] Frank Geels, Marko Hekkert, Staffan Jacobsson, Abingdon: Routledge , 2011, 1, s. 73-92Kapittel i bok, del av antologi (Fagfellevurdert)
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