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  • 1.
    Abad, Marta
    University of Gävle, Department of Technology and Built Environment.
    WORK WITH AGENDA 21 IN EUROPEAN CITIES.: A case of study: the waste's management in Barcelona and Gävle2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Sweden is a long-term world reference country in terms of sustainable development. On the other hand, Barcelona has recently made great efforts in order to improve and to make society aware of the importance of environmental issues. Hence, it would be interesting to investigate if these efforts had succeeded in the waste’s management in Barcelona compared to other leading European cities, and particularly to the case of Gävle.

    In this work, the operation of the management of the urban solid wastes of the two cities is explained.

    First, the objectives marked by Agenda 21 of each locality are exposed. Next, a theoretical perspective about management, generation of wastes and types of waste treatment is provided. In the following chapter, the results of the generation of wastes, selective collection and the treatments of the wastes are shown for both the cases of Barcelona and Gävle until the 2006.

    Finally, the two cities are compared and the results obtained in the management of the wastes are discussed.

    The conclusion in this study is that Barcelona has improved noticeable in terms of environmentally safe management of the wastes. This has happened thanks to the efforts of the city council and of the citizens.

    But It is still necessary to make a major effort by the inhabitants of Barcelona.

  • 2.
    Abbasi, Mahdi
    University of Gävle, Department of Technology and Built Environment.
    Characterization of a 5GHz Modular Radio Frontend for WLAN Based on IEEE 802.11p2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The number of vehicles has increased significantly in recent years, which causeshigh density in traffic and further problems like accidents and road congestions.A solution regarding to this problem is vehicle-to-vehicle communication, wherevehicles are able to communicate with their neighboring vehicles even in the absenceof a central base station, to provide safer and more efficient roads and toincrease passenger safety.The goal of this thesis is to investigate basic physical layer parameters of ainter-vehicle communication system, like emission power, spectral emission, errorvector magnitude, guard interval, ramp-up/down time, and third order interceptpoint. I also studied the intelligent transportation system’s channel layout inEurope, how the interference of other systems are working in co-channel and adjacentchannels, and some proposals to use the allocated frequency bands. On theother hand, the fundamentals of OFDM transmission and definitions of OFDMkey parameters in IEEE 802.11p are investigated.The focus of this work is on the measurement of transmitter frontend parametersof a new testbed designed and fabricated in order to be used at inter-vehiclecommunication based on IEEE 802.11p.

  • 3.
    Abolghasemi Kordestani, Arash
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Farhat, Farshad
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Supply Chain Maturity and Financial Performance: Study of Swedish SMEs2009Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Purpose - The goal of this research is to demonstrate that financial performance of current year is dependent to the amount of maturity of the supply chain processes. This aim is achieved through considering current supply chain process maturities of the firm together with financial performance of prior years.

     

     

    Research question - How supply chain process maturities in relation to financial performance of prior years are related to current financial performance  

     

     

    Methodology - The deductive approach has been followed to use theories and literatures to build the hypothetical model in order to test it empirically.

    This quantitative research is benefited from the primary data of Swedish steel SMEs including the secondary data from financial ratios from Scandinavian financial database

     

     

    Findings - The effect between supply chain process maturity and current year financial performance, the effect between prior year financial performance and current year financial performance, and also total effect of prior year financial performance and supply chain process maturity on current year financial performance proved empirically.

  • 4.
    Agrali, Zahid
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Zubidat, Hamza
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Modell för utvärdering av pallar: en utvärdering av Re-Load pallen2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med examensarbetet är att jämföra en ny pall (Re-Load pallen) mot EUR-pallen för att ta fram för- respektive nackdelar, samt konstatera vilket som är det bättre alternativet. Vidare skall en modell utformas som beskriver hur och vad som skall göras och vad som är viktigt att tänka på när en jämförelse mot EUR-pallen skall genomföras.  Med hjälp av modellen som tagits fram har Re-Load pallen undersökts och jämförts mot EUR-pallen.

  • 5.
    Aguilera, Rafael
    University of Gävle, Department of Technology and Built Environment.
    Implementation of a ceramic coating based upon the concept of emissivity2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 6.
    Ahlbom, Håkan
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Nordlander, Edvard
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Inspirerar teknikämnet i den svenska grundskolan till högre teknikstudier?2009Conference paper (Other academic)
    Abstract [sv]

    Krisen i tillströmningen till svensk teknikutbildning har uppmärksammats kraftigt av avnämarkategorierna den senaste tiden. Fackföreningen Sveriges Ingenjörer hävdar att om inget görs kommer det år 2020 att fattas 50 000 ingenjörer, vilket motsvarar en fjärdedel av arbetsstyrkan i vid bemärkelse om något mer än ett decennium. I ROSE-rapporten beskrivs ett allmänt ointresse för tekniska och naturvetenskapliga studier bland I-ländernas ungdomar i skarp kontrast till ungdomar i utvecklingsländer. Detta beror på att elevernas väljer utbildning efter värderingar och identiteter, vilket inte tycks uppfyllas av tekniska studier.

     

    I föreliggande arbete kommer faktorer för ungdomars studieval att kartläggas. Den svenska grundskolans teknikämne har ett uttalade mål - att utveckla intresse för teknik. Undersökningen vänder sig direkt till eleverna och försöker ge svar på om teknikämnet lever upp till detta mål. De lokala kursplanerna skiljer sig avsevärt och de typer som man kan hitta på skolornas webbplatser är oftast av någon av följande typer:

    1.      Lokal kursplan som i detalj beskriver vad som skall behandlas årskursvis samt de mål som eleven förväntas uppnå.

    2.      Nationella kursplanen utan lokala tolkningar eller specifikationer för ämnets genomförande.

    3.      En synnerligen kort lokal kursplan (mera traditionella ämnen är vanligtvis avsevärt mera specificerade).

    4.      Ingen kursplan för teknikämnet presenteras överhuvudtaget.

     

    Undersökningen tar även hänsyn till lärarnas kompetens inom ämnet och sätter resultatet i relation till bristfällig utbildning.

     

    Frågeställningar: Hur kan man genomföra god utbildning i teknikämnet utan kursplan eller endast med den nationella kursplanen möjligen kompletterad med synnerligen rudimentära tolkningar och specifikationer? Hur kan en lärare med bristfällig utbildning inom ämnet genomföra högkvalitativ undervisning och utveckla elevernas intresse? Finns det en korrelation mellan vagt specificerade kursplaner, lärares brister i utbildning, samhällets signaler om att förverkliga personliga mål i samklang med den egna identiteten, samt den mångfacetterade svenska gymnasieskolan, som kan ge svar på varför elever avstår från högre tekniska studier? Vilka är elevernas synpunkter på teknikämnet som inspirationskälla och vad minns man från undervisningen efter någon tid? I vilken mån utvecklade teknikämnet ett tekniskt intresse och gav det i så fall resultat i valet av gymnasieutbildning?

     

    Undersökningen är primärt baserad på en fenomenologisk kvalitativ metod med djupintervjuer. I detta arbete kommer pilotintervjuer att redovisas – ett sätt att förfina metoden och senare göra mera omfattande intervjuarbete där egna förutfattade meningar om intervjuobjekten minimeras, informationen renodlas och resultat syntetiseras.

     

    Urvalet av intervjuobjekt sker i grundskolans sista år, då eleverna bestämt sig för gymnasieinriktning (oavsett vilket) och därför sannolikt kan ge information om vilka faktorer som inverkade. Urvalet kommer att ske såväl med tanke på kön (teknikutbildning är manligt dominerad) som hemvist (uppväxt på landet eller i tätort) - faktorer som kan ha betydelse i studievalet.

     

    Elever från gymnasiets första (och möjligen andra) år kommer att delta i en enkätundersökning för att undersöka om deras teknikintresse har ändrats. Enkäten kommer senare att utnyttjas på intervjuobjekten från grundskolan, när de påbörjat gymnasiala studier, och resultaten jämförs med den tidigare informationen från intervjuerna.

  • 7.
    Ahlbom, Håkan
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ylva, Bjelksäter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Eva, Hartell
    Stockholms universitet, UTEP.
    Edvard, Nordlander
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Cooperative methods for investigating the influence of Swedish compulsory technology education on pupils’ attitudes to technology2009In: PATT 22  (Pupils' Attitudes Towards Technology), 2009Conference paper (Refereed)
    Abstract [en]

    The number of Swedish students applying to technical education is decreasing, and this fact will lead to a severe shortage of engineers in a just a decade. As an example, the candidates applying to the Royal Institute of Technology (KTH) has reduced by 30 % the last couple of years. Furthermore, the ROSE report clearly describes young people’s lack of interest in science and technology in the industrialised world in sharp contrast to the situation in the developing countries.

    Why is the interest for technical education decreasing? What makes other fields of education more popular? What image of technology does the compulsory school deliver?

    Technology was introduced as a mandatory subject in Swedish compulsory school in 1980 and got its own syllabus when the current national curriculum was introduced in 1994. One of the goals of the Swedish compulsory school is to develop an interest for technology as well as capability and judgement in handling technical issues.

    In what way does the Swedish compulsory school work with this goal? Is the school successful in making pupils interested? What are the pupils’ opinions?

    Each school can decide when and how the pupils get technology education, but every pupil is expected and entitled to reach the national goals.

    To get an overall picture of the technology subject questions will be investigated as parts of tree different Ph.D. projects.

    • How do we actually know that pupils learn what they are entitled to?
    • How is the technology syllabus interpreted, in theory and practice?
    • Does the technology subject really develop an interest for technology and does it inspire to further technical studies? 

    In order to find out if pupils reach the national goals in technology, a questionnaire is launched in schools all over Sweden. The interpretation of the syllabus will be studied through observations comparing teaching practice with the local planning of the technology subject. To get answers, whether the technology subject has any impact on the interest and the choice of further studies, interviews are made among students and teachers in compulsory school as well as in upper secondary school.

    The findings of the cooperating projects will together contribute with answers about the state of the technology education in the Swedish compulsory school system, and how the subject could be developed in the future.

  • 8.
    Ahnfeldt, Tomas
    University of Gävle, Department of Technology and Built Environment.
    Geometry for CAD Toolbox2008Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 9.
    Aittamaa, Christina
    University of Gävle, Department of Technology and Built Environment.
    Inmätning av fastigheten Hållsta 2:3, Hudiksvall2007Student paper second term, 10 points / 15 hpStudent thesis
    Abstract [sv]

    Detta projekt har genomförts på mark- och mätningsavdelningen i Hudiksvalls kommun och projektets område är beläget norr om Hudiksvall, ca 6 km från centrala Hudiksvall vid norra infarten till E4:an.

    I området ligger en friskola, en gymnasieskola som heter ”Glada Hudik-skolan”. I skolans lokaler har det tidigare bedrivits hotellverksamhet i många år, f.d. Hammering Hotell. Hösten 2006 öppnade skolan sina portar och de räknar med att öka antalet elever varje läsår. I närheten av skolan finns den kända travbanan, Hagmyren.

    Syftet med arbetet var att göra en inmätning av fastigheten Hållsta 2:3, eftersom det inte fanns några inmätningar där tidigare. Stompunkter mättes in både i plan och höjd, därefter gjordes det detaljmätningar. Koordinatsystemet i plan i Hudiksvall är RTR10 2.5 gon V 0:- 15 och i höjd RH 70. Efter stom- och detaljmätningarna konstruerades en primärkarta i Geosecma som är ett kartprogram.

    I den här rapporten kommer mätmetoder, beräkningar, dokumentation och kartframställning att redovisas.

    Målet med projektet är att kommunen skall få nytta av inmätningarna i framtiden för olika projekteringar och att jag skall få mer erfarenhet av både mätning och kartframställning. Jag får även kunskaper om hur det går till på arbetsplatsen, tankegångar kring ett projekt och lärdomar av att arbeta självständigt.

  • 10.
    Akander, Jan
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Stojanovic, Bojan
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Hallberg, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Simulated Long-term Thermal Performance of a Building That Utilizes a Heat Pump System and Borehole2008In: Durability of Building Materials & Components 11: Globality and Locality in Durability / [ed] A. Nil Türkeri, Özkan Sengül, Istanbul, Turkey: Istanbul Technical University, 2008Conference paper (Refereed)
    Abstract [en]

    Over the last decades, installation and use of heat pumps has grown rapidly in Sweden, to the extent that these mainly or partly heat roughly 25 % of the heated floor space in single-family houses. A majority are ground coupled where the heat exchanger is a borehole of 60-220 m depth. As the heat pump system operates, heat extraction will in time reduce borehole temperatures, rendering lowered efficiency of the heat pump system thus directly affecting its economical and environmental aspects. Within the building sector, durability and life performance dynamics of energy systems is often not reflected upon. System performance and efficiency is assumed to be static over time, changing only due to different operation scenarios. This paper serves to quantify the long-term thermal performance degradation of a component, in this case the borehole, and how the degradation of this component affects performance-over-time of an entire system, in this case the heating system of the building. A dynamic thermal simulation model is used to assess the long-term thermal performance of the borehole. The building, which the heat pump serves, is assumed to be a typical Swedish house with normal energy consumption. Simulation results show that the depth of the borehole is of great importance to limit over-time temperature drops. The efficiency of the heat pump system is directly dependent of temperatures in the borehole. How the overall system performance is affected by component performance degradation, is highlighted.

  • 11.
    Al Tanany, Ahmed
    University of Gävle, Department of Technology and Built Environment.
    A Study of Switched Mode Power Amplifiers using LDMOS2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    This work focuses on different kinds of Switch Mode Power Amplifiers (SMPAs) using LDMOS technologies. It involves a literature study of different SMPA concepts. Choosing the suitable class that achieves the high efficiency was the base stone of this

    work. A push-pull class J power amplifier (PA) was designed with an integrated LC resonator inside the package using the bondwires and die capacitances. Analysis and motivation of the chosen class is included. Designing the suitable Input/Output printed circuit board (PCB) external circuits (i.e.; BALUN circuit, Matching network and DC

    bias network) was part of the work. This work is done by ADS simulation and showed a simulated result of about 70% drain efficiency for 34 W output power and 16 dB gain at 2.14 GHz. Study of the losses in each part of the design elements is also included.

    Another design at lower frequency (i.e.; at 0.94 GHz) was also simulated and compared to the previous design. The drain efficiency was 83% for 32 W output power and 15.4 dB Gain.

  • 12.
    Al-Asad, Zahir
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Implementation of NURBS Objects in a Ray TracingCode for RCS Simulation2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 13.
    Almgren, Björn
    University of Gävle, Department of Technology and Built Environment.
    Dynamic load modulation2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The purpose of this master thesis was to study if the drain efficiency of power amplifiers can be maintained at power back off using a technique called load modulation.

    The amplifier classes studied are E, F and D-1. The target figure was to obtain a 10 to 12 dB dynamic range of amplitude with reasonable efficiency. Studies of power amplifiers have been made to understand how power is generated. Several different load modulation networks have been evaluated. Attempts to derive design equations for the modulation networks have also been done.

    The thesis work was carried out with simulations in ADS 2006. As active devices commercially available bare-die transistor models have been used. The power rating of the dies are 15 W.

    A dynamic range of amplitude of over 15 dB has been achieved with drain efficiency greater than 60 percent. The peak output power is in the 40 – 45 dBm range.

  • 14.
    Alonso, Laura
    University of Gävle, Department of Technology and Built Environment.
    Assessment of waste and biofuel resources for district heating in the region of Gävle in Sweden2008Independent thesis Advanced level (degree of Magister), 10 points / 15 hpStudent thesis
    Abstract [en]

    Fuel availability and security of supply are two of the most important factors in the well functioning of a company like Gävle Energi. Another important factor is the price of the fuels used. The transportation cost plays also an important role when purchasing fuels from different sources. Currently the fuels used in Gävle Energi are mainly woody biofuels, but waste and peat could also be used in the future.

    The aim of this thesis is to provide an overview of the different available biofuels in the region of Gävle. The fuels considered in the study are:

    - Bark

    - Forest Residues

    - Wood waste

    - Pellets and Briquettes

    - Garbage/waste materials

    - Peat

    The research is focused on the physical properties of the fuels, their price and transportation cost, environmental and legislation issues and the availability in the region of Gävle. A 10-year perspective is defined for an estimated availability of the different fuels in te region.

  • 15.
    Al-Tahir, Hibah
    University of Gävle, Department of Technology and Built Environment.
    Multidimensional Measurements: on RF Power Amplifiers2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Abstract

    In this thesis, a measurement system was set to perform comprehensive measurements on RF power amplifiers. Data obtained from the measurements is then processed mathematically to obtain three dimensional graphs of the basic parameters affected or generated by nonlinearities of the amplifier i.e. gain, efficiency and distortion. Using a class AB amplifier as the DUT, two sets of signals – both swept in power level and frequency - were generated to validate the method, a two-tone signal and a WCDMA signal. The three dimensional plot gives a thorough representation of the behavior of the amplifier in any arbitrary range of spectrum and input level. Sweet spots are consequently easy to detect and analyze. The measurement setup can also yield other three dimensional plots of variations of gain, efficiency or distortion versus frequencies and input levels. Moreover, the measurement tool can be used to plot traditional two dimensional plots such as, input versus gain, frequency versus efficiency etc, making the setup a practical tool for RF amplifiers designers.

    The test signals were generated by computer then sent to a vector signal generator that generates the actual signals fed to the amplifier. The output of the amplifier is fed to a vector signal analyzer then collected by computer to be handled. MATLAB® was used throughout the entire process.

    The distortion considered in the case of the two-tone signals is the third order intermodulation distortion (IM3) whereas Adjacent Channel Power Ratio (ACPR) was considered in the case of WCDMA.

  • 16.
    Amiri, Shahnaz
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Trygg, Louise
    Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Assessment of the natural gas potential for heat and power generation in the County of Östergötland in Sweden2009In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 37, no 2, p. 496-506Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to investigate the potential use of natural gas for heat and power production for the municipality of Linkoping, Norrkoping and Finspang in the County of Ostergotland, Sweden. The results of the study revealed that these three municipalities with the present heating demand can convert 2030 GWh/year of the present fuel mixed to natural gas. The expansion of natural gas provides the possibility to increase the electricity generation with approximately 800 GWh annually in the County of Ostergotland. The global emissions of CO(2) reduce also by approximately 490 ktonne/year by assuming the coal condensing power plant as the marginal power plant. The total system cost decreases by 76 Mkr/year with the present electricity price which varies between 432 and 173 SEK/MWh and with 248 Mkr/year if the present electricity price increases to 37% which is approximately corresponding to European electricity prices. Sensitivity analysis is done with respect to the different factors such as price of electricity, natural gas, etc. The findings show that increased price of electricity and increased district heating demand increases the profitability to convert to natural gas using CHP plant. (C) 2008 Elsevier Ltd. All rights reserved.

  • 17.
    Anavberokhai, Isah
    University of Gävle, Department of Technology and Built Environment.
    Introducing GIS and Multi-criteria analysis in road path planning process in Nigeria: A case study of Lokoja, Kogi State2008Independent thesis Advanced level (degree of Magister), 15 points / 22,5 hpStudent thesis
    Abstract [en]

    In planning a suitable road network, planners put into consideration factors like gradients or slope of the area, available land-use and soil type, community or national landmarks and governmental interest. These different considerations and interest make the planning process complex and as such there might be confusion of interest in the decision making. The use of GIS and Multi-criteria analysis has helped planners to achieve desired and more accurate results and as such reducing the complex nature in the planning process allowing different stakeholders to reach a general conclusion.

    Multi-criteria analysis (MCA) prevents the imposition of limit on the form of criteria and gives opportunity to decision makers to enter their own judgments. This provides a better communication among the decision makers and the entire community and as such creating a more open choice for analysis and possible changes if necessary. The aim of this thesis is to introduce the possibility of using GIS and MCA in road path planning in Nigeria, using Lokoja, the capital of Kogi state as a case study.

    In actualizing the aim, satellite images of the area of study was obtained from the Landsat home page and analyzed to derive the land-use map. The land-use over the area of study was classified into five different classes using the unsupervised method of classification. A DEM over the area of study was downloaded from the website of the Consortium of Spatial information (CSI) and the DEM was used to derive the slope map over the area of study and the analytic hierarchy process (AHP) method was used in weighting the criterions according to preference.

    As the conclusion of the analysis, a road path between two points was obtained. The start point of the road was located on an approximate coordinate of 219002, 958986 meters and the destination point on an approximate coordinate of 320322, 878101 meters. The start and destination point were selected randomly without any pre-knowledge of the area. The thesis has succeeded in showing that it is possible to determine a road path between two points using Geographic information system (GIS) and Multi-criteria analysis in Nigeria.

  • 18.
    Anavberokhai, Isah
    University of Gävle, Department of Technology and Built Environment.
    Mapping land-use in north-western Nigeria (Case study of Dutse)2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    This project analyzes satellite images from 1976, 1985 and 2000 of Dutse, Jigawa state, in north-western Nigeria. The analyzed satellite images were used to determine land-use and vegetation changes that have occurred in the land-use from 1976 to 2000 will help recommend possible planning measures in order to protect the vegetation from further deterioration.

    Studying land-use change in north-western Nigeria is essential for analyzing various ecological and developmental consequences over time. The north-western region of Nigeria is of great environmental and economic importance having land cover rich in agricultural production and livestock grazing. The increase of population over time has affected the land-use and hence agricultural and livestock production.

    On completion of this project, the possible land use changes that have taken place in Dutse will be analyzed for future recommendation. The use of supervised classification and change detection of satellite images have produced an economic way to quantify different types of landuse and changes that has occurred over time.

    The percentage difference in land-use between 1976 and 2000 was 37%, which is considered to be high land-use change within the period of study. The result in this project is being used to propose planning strategies that could help in planning sustainable land-use and diversity in Dutse.

  • 19.
    Anavberokhai, Isah O.
    University of Gävle, Department of Technology and Built Environment.
    Environmental Aspects Review: A Case Study of Two Sawmills in Etsako-West, Edo State Nigeria2008Independent thesis Advanced level (degree of Magister), 10 points / 15 hpStudent thesis
    Abstract [en]

    The forests are essential for healthy environment. Trees which are part of the

    forest help to stabilize the forest soil, improve soil fertility, reduce the velocity of

    wind, protect watershed and reduce the amount of carbon released into the

    atmosphere. Many industries use trees as raw materials and in most cases impact

    the environment, but there are great differences in the impact they make. There is

    a need therefore to continually evaluate the operational activities of these

    industries to ensure that the environment is protected. The use of environmental

    management systems like ISO and EMAS standards has helped in the evaluation

    of organizations and industries.

    In this thesis, two sawmills Iretunde and Irepodun in Etsako-West local

    government area Edo state Nigeria were evaluated with the aim to determine their

    operational activities and how the environment is being affected by them. Subaims

    were to determine the most significant environmental aspects of the sawmill

    and their organizational structure. In actualizing the aim of this thesis, literature

    review, site investigation as well as oral interview of the staff and management of

    both sawmills were conducted. In the evaluation of the environmental aspects, the

    detailed method of environmental impact evaluation by Ammenberg (2004) was

    used were each environmental aspect that was weighted against nine identified

    criteria.

    The result obtained from the environmental aspect evaluation of both sawmills

    shows that the use of raw materials and emissions to air are the most significant

    environmental aspects. In conclusion, it was observed that the both sawmills are

    well structured and carry out their operational activities effectively. Neither of

    them has registered under any environmental management system but there is a

    need for them to do so in order to help check their operational activities in order to

    reduce their environmental impact.

  • 20.
    Andersen, O.
    et al.
    Ericsson AB.
    Wisell, David
    Ericsson AB.
    Keskitalo, Niclas
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Measurement of ACLR with high dynamic range2008In: IEEE MTT-S International Microwave Symposium Digest, Atlanta, GA, 2008, p. 273-277Conference paper (Other academic)
    Abstract [en]

    In this paper a method to overcome the insufficient dynamic range of RF measurement instruments, i.e. signal generators and spectrum analyzers, for distortion measurements on feedforward and other highly linear amplifiers, is discussed. A circuit board is designed, built and verified. Its performance is found to be superior to traditional methods using filters, both from a technical performance and flexibility standpoint as well as from an economic view. ACLR measurements for WCDMA signals can be done well below -70 dBc using the produced circuit board. © 2008 IEEE.

  • 21.
    Andersen, Olav
    et al.
    Ericsson.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Keskitalo, Niclas
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A Test-Bed Designed to Utilize Zhu’s General Sampling Theorem to Characterize Power Amplifiers2009In: Instrumentation and measurement technology conference 2009 I2MTC '09 IEEE, Singapore, 2009, p. 201-204Conference paper (Refereed)
    Abstract [en]

    Characterizing power amplifiers require test set-ups with performance superior to the power amplifiers. A commonly used method is to use an IQ-demodulator. However, problem arises due to imperfections in the demodulator such as IQ-imbalance; an alternative method is to use a direct down converter to intermediate frequency. The drawback then is the limited bandwidth. However, the required bandwidth of the ADC does not need to be exceptional. According to Zhu’s general sampling theorem is it enough to sample the output signal at the Nyquist rate of the input. However, even though the required sampling rate is reduced the demands on the analog bandwidth remains. Unfortunately, commercially available instruments such as vector signal analyzers can not be used for this purpose since their analog bandwidth is too small. In this paper a test-bed is designed to utilize the Zhu’s general sampling theorem. The RF front-end has frequency range of 500 MHz – 2.7 GHz and a bandwidth of 1 GHz. All performance data are verified with measurements.

  • 22.
    Andersen, Olav
    et al.
    Ericsson Telecom AB, Gävle, Sweden.
    Wisell, David
    Ericsson Telecom AB, Stockholm, Sweden.
    Staenvard, Patrik
    Ericsson Telecom AB, Gävle, Sweden.
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Extending the Bandwidth and Dynamic Range of Old RF Instruments to Meet State-of-the-Art Performance, Using a Synthetic Instrument Approach2009In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 58, no 2, p. 248-254Article in journal (Refereed)
    Abstract [en]

    A decrease in life cycle cost is a key issue for testing mobile communication systems. The rapid development and edge technology requires high-performance instruments and state-of-the-art measurement technology. New investments are expensive, but even older generation instruments are capable of extending their bandwidth and dynamic range to meet even the latest Third-Generation Partnership Project (3GPP) cellular measurement requirements by the addition of external hardware using a synthetic instrument approach. The novelty of this paper is the high performance on the most crucial parameters, i.e., the dynamic range and bandwidth achieved by only replacing some parts of the legacy instrument. Moreover, the demonstrated direct IF synthesis has a high degree of novelty at wide modulation bandwidths. It is desired to use virtual/synthetic instruments and make the signal processing in the software independent of the hardware, i.e., software-defined measurements (SDMs). In this paper, a state-of-the-art experimental setup for signal generation and signal analysis is demonstrated. A direct IF synthesis is used to generate a wideband code-division multiple-access (WCDMA) carrier with more than 72-dB adjacent carrier leakage ratio (ACLR) up to 12 parallel carriers with more than 68-dBc ACLR over a total bandwidth of 100 MHz. The signal analysis capabilities (e.g., ACLR performance) for a WCDMA carrier is better than -70 dBc and for a continuous wave better than -85 dBc over a bandwidth of 42.5 MHz. The critical RF downconverter in the setup is carefully designed not to degrade the dynamic range performance.

  • 23.
    Andersson, Mikael
    University of Gävle, Department of Technology and Built Environment. Industriell ekonomi.
    Discrete Event Operational Simulation in the Manufacturing System1999Licentiate thesis, monograph (Other scientific)
  • 24.
    Andersson, Tommy
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Department of Technology and Built Environment.
    Algilany, Gazwan
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Department of Technology and Built Environment.
    Konstruktion Signalgenerator2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    SAAB Aerotech division FGR in Arboga builds and develops equipment and components used in both military and civilian applications. To build a test system for a specific project that SAAB is responsible for requires a simple signal generator that can provide a pulse modulated signal. The need to buy a new advanced signal generator for example from Agilent is not as profitable as the instrument is expensive and contains features that SAAB does not require in their applications and test systems. That was the reason why SAAB offers two students a thesis where the goal is to construct a signal generator in accordance with what SAAB requests.

    This thesis contains several different phases. The first step was a meeting with our supervisor Mats Bergman and by reading the data sheets for components to be used in the project, with these information and specifications that we have received from SAAB we started to construct the signal generator.

    What we did during the construction work was to simulate and draw a schematic to be able to design the circuit board. Simulation was done both in software and on laboration board. The card is then ordered from a circuit board manufacturer in Bulgaria. On the finished card the components will be fitted. Then the card will plugged in into a rack and then presented finished as a signal generator that can be used in a test system.

    The final results of all phases are satisfactory in the part of design and laboratory work. The finished mother board was tested and test results corresponded well with the theory. The final results will be presented with a spoken presentation at the University of Gävle and at SAAB Aerotech in Arboga division FGR

  • 25.
    Anton, Raul
    et al.
    TECNUN, University of Navarra, Navarra, Spain.
    Jonsson, Hans
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping.
    Compact CFD Modeling of EMC screen for radio base stations: a porous media approach and a correlation for the directional loss coefficients2007In: IEEE transactions on components and packaging technologies (Print), ISSN 1521-3331, E-ISSN 1557-9972, Vol. 30, no 4, p. 875-885Article in journal (Refereed)
    Abstract [en]

    A methodology to obtain the directional pressure loss coefficients in a porous media model of an electromagnetically compatible screen of a radio base station model is presented. The directional loss coefficients of this compact model are validated against a detailed computational fluid dynamics model not only by comparing the total pressure drop, but also by evaluating the flow pattern after the screen. The detailed model was validated in an earlier article by the authors. A parametric study is conducted for 174 cases. Seven parameters were investigated: velocity, inlet height, screen porosity, printed circuit board (PCB) thickness, inlet-screen gap, distance between two PCBs and screen thickness. Based on the compact model parametric study, two correlations for the directional loss coefficients are developed as a function of the Reynolds number and the above geometrical parameters. The average disagreement between the compact model that uses the directional loss coefficients from the correlations and the detailed model was of 3% for the prediction of the total pressure drop and less than 6.5% and 9.5% for two coefficients that accurately characterize the flow pattern.

  • 26.
    Antón, Raul
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Department of Mechanical Engineering, TECNUN, University of Navarra, Navarra, Spain; Division of Applied Thermodynamics and Refrigeration, KTH Energy Technology, Royal Institute of Technology, Stockholm, Sweden.
    Jonsson, Hans
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Division of Applied Thermodynamics and Refrigeration, KTH Energy Technology, Royal Institute of Technology, Stockholm, Sweden.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Detailed CFD Modelling of EMC Screens for Radio Base Stations: A Parametric Study2009In: IEEE transactions on components and packaging technologies (Print), ISSN 1521-3331, E-ISSN 1557-9972, Vol. 32, no 1, p. 145-155Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to make a parametric study of the hydraulic resistance and flow pattern of the flow after an electromagnetic compatibility screen and between two printed circuit boards (PCBs) in a model of a 90 degrees subrack cooling architecture. The parametric study is carried out using a detailed 3-D model of a PCB slot. The detailed model was experimentally validated in a previous paper by the authors. Seven parameters were investigated: velocity, inlet height, screen porosity, PCB thickness, distance between two PCBs, inlet-screen gap and screen thickness. A correlation for the static and dynamic pressure drop, the percentage of dimensionless wetted area, A(omega)*, and the RMS* factor (a function of the How uniformity along the PCB) after the screen is reported as a function of six geometrical dimensionless parameters and the Reynolds number. The correlations, that are based on 174 three dimensional simulations, yield good results for the total pressure drop, in which the values are predicted within the interval of +/- 15%. For the, A(omega)*, all the predicted values are within the interval of +/- 22% of the observed values. Finally, for the RMS* factor, the majority of the values also have a disagreement of less than 20% of the observed values. These last two parameters are believed to provide a correct insight about the flow pattern after the screen.

  • 27.
    Antón, Raúl
    et al.
    Department of TECNUN, University of Navarra, Navarra, Spain.
    Jonsson, Hans
    Royal Institute of Technology, Stockholm.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Division of Energy Systems, Department of Management and En- gineering, Linköping University, Linköping, Sweden.
    Detailed CFD modeling of EMC screen for radio base stations: a benchmark study2007In: IEEE transactions on components and packaging technologies (Print), ISSN 1521-3331, E-ISSN 1557-9972, Vol. 30, no 4, p. 754-763Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to investigate the performance of five well-known turbulence models, in order to find a model that predicts the details of the flow patterns through an electromagnetic compatibility (EMC) screen. The turbulence models investigated in the present study are five different eddy-viscosity models; the standard k-epsilon model, the renormalization group (RNG) k-epsilon model, the realizable k-epsilon model, the standard k-omega model, as well as the shear stress transport k-w model. A steady-state 3-D detailed model, which serves as the most accurate representation of the model, was used in order to evaluate the details of the airflow paths and pressure field. The flow was assumed to be isothermal, turbulent and incompressible. A general model that covers a considerable range of velocities and geometries was validated experimentally by wind tunnel measurements. The result shows that for most of the k-epsilon models used with correct y(+) and mesh strategy, the pressure drop and the velocity field deviation is small compared to experimental data. The k-omega models overpredict the overall pressure drop. When using the RNG k-epsilon model, the total static pressure drop predicted differs around 5%-10% and the average velocity deviation at several locations before and after the screen is around 5%.

  • 28.
    Antón, Raúl
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Royal Institute of Technology, Stockholm, Sweden; TECHUN, University of Navarra, San Sebastián, Spain.
    Jonsson, Hans
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Royal Institute of Technology, Stockholm, Sweden.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Detailed CFD modelling of EMC screen for radio base stations: A conjugate heat transfer problem2007In: International Journal of Heat Exchangers, ISSN 1524-5608, Vol. 8, no 1, p. 95-116Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to perform an experimental as well as CFD investigations of the conjugate heat transfer problem in a sub-rack slot model. A steady-state three-dimensional detailed model, which serves as the most accurate representation of the model, was used in order to evaluate the details of the airflow paths and temperature field. A general model that covers a considerable range of velocities, screen porosities and heat fluxes was validated experimentally by wind tunnel measurements. The result shows that the RNG k-ε model used with correct y+ and mesh strategy accurately predicts the temperature field. The average temperature deviation at several locations is less than 4% compared to experimental data. The influence of the velocity, screen porosity, heat flux and presence of the EMC screen on the PCB temperature field is commented. © 2007 R.T. Edwards, Inc.

  • 29.
    Antón Remírez, Raúl
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Experimental and numerical study of the thermal and hydraulic effect of EMC screens in radio base stations: detailed and compact model2006Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    Today’s telecommunication cabinets use Electro Magnetic Compliance (EMC) screens in order to reduce electromagnetic noise that can cause some miss functions in electronic equipment.

    Many radio base stations (RBSs) use a 90-degree building architecture: the flow inlet is perpendicular to the EMC screen, which creates a complex flow, with a 90-degree air turn, expansions, compressions, perforated plates and PCBs. It is of great interest to study how the EMC screen interacts with the rest of components and analyze the total pressure drop and how much the flow pattern changes due to the placement of the screen.

    Velocity, pressure and temperature measurements as well as flow pattern visualizations have been carried out to gain good insight into the flow and heat transfer characteristics in a subrack model of an RBS. Furthermore, these measurements have been very useful for validating detailed CFD models and evaluating several turbulence models.

    Nowadays, industrial competition has caused a substantial decrease in the time-to-market of products. This fact makes the use of compact models in the first stages of the design process of vital importance. Accurate and fast compact models can to a great extent decrease the time for design, and thus for production.

    Hence, to determine the correlations between the pressure drop and flow pattern on the PCBs as a function of the geometry and the Reynolds number, based on a detailed CFD parametric study, was one objective. Furthermore, the development of a compact model using a porous media approach (using two directional-loss coefficients) has been accomplished. Two correlations of these directional loss coefficients were found as a function of the geometry and Reynolds number.

  • 30.
    Ardavan, Mehdi
    University of Gävle, Department of Technology and Built Environment.
    Metamaterial: A field magnitude dependent and frequency independent model2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    In all attempts to analyze and realize Left-Handed materials, so far, most researchers have used the same idea of extracting only some or certain behaviors of Metamaterials from a set of unit cells gathered together in a designed order. Nevertheless meeting all criteria in order to consider a media as real double-negative material has never come true.

    Starting with criticizing and arguing the validity of calling any set of unit cells as a medium of propagation, the work at hand will go further demonstrating analogies between a medium which could be assigned permittivity or permeability factors and the medium consisting a set of unit cells.

    After presenting the critical analysis on previous studies in the field, here it is shown that it is impossible to build Metamaterials using any number of passive unit cells. A deep insight into the concept of phase and group velocities as well as Poynting’s vector will reveal weakness of the public perception of their relation with each other. Unlike the past and current trend in analyzing these two velocities in meta-materials, they will be proven to possess the same direction.

    Moreover, in this work, a solid proof over violation of energy conservation in the intersection plane between a normal material and a Left Handed material is presented which requires us to believe and accept generation of energy at this plane. This view will consequently leave meaningless all attempts to build meta-materials by passive elements.

    In present work a method is proposed at which a material with positive permittivity and permeability can behave like and yield all characteristics of Metamaterials only if the foregoing parameters, while remaining positive, can vary and be governed by the magnitude of the electromagnetic field. Independence of this method from frequency broadens the range of its application and also the interest it may attract.

  • 31. Arlinger, Stig
    et al.
    Hagerman, Björn
    Kjellberg, Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Kähäri, Kim
    Landström, Ulf
    Poulsen, Torben
    Musik och höga ljudnivåer: praktiska riktlinjer för musik- och underhållningsbranschen2009Report (Other academic)
  • 32. Arlinger, Stig
    et al.
    Kjellberg, Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Landström, Ulf
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Kähäri, Kim
    Hagerman, Björn
    Poulsen, Torben
    Bengtsson, Johanna
    Musik, musiker och hörsel: en kunskapssammanställning om höga ljudnivåer och hörselskaderisker i musik- och underhållningssektorn2007Report (Other academic)
  • 33.
    Aroshvili, Giorgi
    University of Gävle, Department of Technology and Built Environment.
    GaN HEMT and MMIC Design and Evaluation2008Independent thesis Advanced level (degree of Master), 20 points / 30 hpStudent thesis
    Abstract [en]

    Gallium Nitride based devices due to their inherent material properties are considered as one of the most promising devices to realize high power, high frequency transistors with lower power consumption in next-generation applications. Although the technology has been studied since early 1970s, there is still a vast room and expectations in its yet unachieved findings. In present work the GaN technology is explored and state-of-the-art studies of GaN based HEMTs and their application in MMICs are presented. Different designs are presented and evaluated and the results are reported. In particular the HEMT performance is studied in terms of DC in addition to large signal conditions, where the device’s performance becomes function of power levels it is driven with. The peculiarities and challenges of building an automated Load-Pull setup are outlined and analysis for further improvements is presented.

  • 34.
    Arvidsson, Karin
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Att ändra examinationsform: fokus på lärandet men dilemma att betygssätta2004In: Kunskap och lärande i den högre utbildningen: lärarreflexioner från praktiken / [ed] Sara Dahlström och Göran Fransson, Gävle: Högskolan i Gävle , 2004, p. 12-18Chapter in book (Other (popular science, discussion, etc.))
  • 35.
    Arvidsson, Karin
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Environmental management at Swedish universities2004In: International Journal of Sustainability in Higher Education, ISSN 1467-6370, E-ISSN 1758-6739, Vol. 5, no 1, p. 91-99Article in journal (Refereed)
    Abstract [en]

    Since1996, all Swedish public authorities, which includes most universities, have been made responsible for contributing to the sustainable development of the society. Swedish universities are thus required to submit annual environmental reports about their policies, structures and actions. This study provides a review of the activities that Swedish universities have undertaken so far. Reports from the year 2000 show that all 25 participating universities conducted the first environmental review. Most universities stopped there, although one – Mälardalen University – has gone all the way to ISO 14001 certification. The findings of the study suggest that universities, which have been participating for some years in the project, are further along the line than those that joined recently. There is also some indication that environmental-management-system (EMS) work is easier for the smaller universities, which can mobilise around a single goal.

  • 36.
    Assefa, Getachew
    et al.
    School of Chemical Sciences and Engineering, Royal Institute of Technology, Industrial Ecology, Stockholm, Sweden.
    Glaumann, Mauritz
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Malmqvist, Tove
    Department of Infrastructure, Royal Institute of Technology, Built Environment Analysis, Stockholm, Sweden.
    Kindembe, Beatric
    White Arkitekter, Stockholm, Sweden.
    Hult, Marie
    Swedish University of Agricultural Sciences, Landscape Architecture, Uppsala, Sweden.
    Myhr, Ulla
    Swedish University of Agricultural Sciences, Landscape Architecture, Uppsala, Sweden.
    Eriksson, Ola
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Environmental assessment of building properties - where natural and social sciences meet: the case of EcoEffect2007In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 42, no 3, p. 1458-1464Article in journal (Refereed)
    Abstract [en]

    The EcoEffect method of assessing external and internal impacts of building properties is briefly described. The external impacts of manufacturing and transport of the building materials, the generation of power and heat consumed during the operation phase are assessed using life-cycle methodology. Emissions and waste; natural resource depletion and toxic substances in building materials are accounted for. Here methodologies from natural sciences are employed. The internal impacts involve the assessment of the risk for discomfort and ill-being due to features and properties of both the indoor environment and outdoor environment within the boundary of the building properties. This risk is calculated based on data and information from questionnaires; measurements and inspection where methodologies mainly from social sciences are used. Life-cycle costs covering investment and utilities costs as well as maintenance costs summed up over the lifetime of the building are also calculated.

    The result presentation offers extensive layers of diagrams and data tables ranging from an aggregated diagram of environmental efficiency to quantitative indicators of different aspects and factors. Environmental efficiency provides a relative measure of the internal quality of a building property in relation to its external impact vis-à-vis its performance relative to other building properties.

  • 37.
    Aurusell, Louise
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för byggnadskvalitet.
    Ytbehandling baserad på hampolja2008Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The varieties of paint are today very big, but many of the more popular paints are less than environmental friendly. The uses of fossilized fuel in paints are common because these paints dry fast and are color true. It would be beneficial for the environment if more renewable source were used to produce paint. Linseed oil is an old base for oil paints. It is renewable and easily procured. But linseed oils have some aspects that give it a bad reputation. There are problems with the slow drying and the color turning yellow when exposed to darkness for long periods of time. Researchers at KTH have connected the yellowing to linolenic acid, one of the common fatty acids in linseed oil (Svensson, M. Johansson, M, Stenberg, C. Samuelsson, J. 2003). Hempseed oil is also a drying oil like linseed, but hempseed oil contains a larger amount of the fatty acid linoleic acid and a smaller amount of linolenic acid (http://en.wikipedia.org/wiki/Hempseed_oil). This might mean that oil paint based on hempseed-oil instead of linseed-oil might have fewer problems with yellowing.Experiments with the two oils have been executed side by side in order to compare results. Two oil paints have also been produced and tested. Test pieces painted with the two different oil paints were exposed to moisture, daylight and complete darkness and then compared.

  • 38.
    Azhar, Ahsan
    University of Gävle, Department of Technology and Built Environment.
    Large Signal RF Measurement Systems and Implementation of a Tuned Receiver System2008Independent thesis Advanced level (degree of Master), 20 points / 30 hpStudent thesis
    Abstract [en]

    This report shows a survey of sate of the art different large signal RF measurement systems. Such measurement systems are discussed in detail with respect to their architecture, method of measurement, calibration, accuracy, dynamic range and bandwidth. Finally, a RF measurement system for large signal was designed and implemented. This measurement system was based on a tuned receiver. Harmonic distortion type measurements were taken by this system and time domain waveforms were reconstructed using external software.

  • 39.
    Badham, Richard
    et al.
    University of Wollongong.
    McLoughlin, Ian
    University of Wollongong.
    Niss, Camilla
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    I´m Alright Jaques': Irony and Commitment in Changing Culture Change Programs2004In: 18th Annual Conference of the Australian and New Zealand Academy of Management (ANZAM), 2004Conference paper (Other (popular science, discussion, etc.))
  • 40.
    Barcos, Daniel
    University of Gävle, Department of Technology and Built Environment.
    Energy Survey: Energy Audit for ICA Maxi in Sandviken2009Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
  • 41.
    Bashir, Babar
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Designing of High Reflectance Distributed Bragg reflectors (DBRs),mirrors using AlGaInN material system in the UV wavelength range2009Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 42.
    Batti, Erich
    University of Gävle, Department of Technology and Built Environment. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Fjärrkyla till Gävletätort: temperaturberäkningar av distributionsledningar2008Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In recent year, the need of providing buildings with cooling has increased, especially in offices there the used electrical equipment in the form of computers, lighting and other electrical equipment. In order to chill away the heat that is given from these equipments used for current old chill machines that are owned by real-estate owners in Gävle. Instead in order to change or to fulfil these machines with environment dangerous cold mediums come the thought with providing Gävle with district chill which is a distinguished alternatives and concurrent is environmentally friendly.

     

    The most front aim with this work has been to do temperature calculations around distribution pipes that will be placed on bottom of Gavleån without bigger complications such as isolated pipes and digging for steam disposition, and to convert an assessment if this is possible. Another aim was to do pressure case calculations on these pipes. The work is provided of SWECO-THEORELLS in Gävle, the company had already done temperature calculations, and the work was allocated also in order to compare the results.

     

    The temperature calculations were resort to heat transfer's principles on swiftly-flowing fluid bodies, this in order that the pipes are surrounded by streaming water. The water temperature was assumed to 20ºC that is huge heavily assumption in order to last on a depth up to 6m. The conclusive temperature to the heat bills of exchange is 5.5ºC.

     

    The pressure case calculations were done in one MICROSOFT-EXCEL document, the starting points each one previous course during the education's time that was called energy resources which facilitated calculations.

     

    Arrived results hopefully will lie to shallow for a continued work and an execution of these planning's.

     

    The following results have been brought about:

    • A temperature on 5.8ºC is received to long away located subscriber at 20ºC hot water
    • 203 kPa pressure case on flow into, only distribution pipes

     

     

     

     

     

    The following conclusions could be extracted:

    • A certain difference was detected between earlier calculations, since considerations been taken to extreme relations so decreases this difference's importance
    • Reduction of water flow during the summer mean one risk while spirit that does the delivery of desired temperature uncertain, special during the hottest days

    That estimated available pressures will not cover the need in accordance with calculations performed in this work

  • 43.
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Center for RF-Measurement Technology2008In: Radio Science and Communication, RVK08, 2008Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    In February 2006 the Centre for RF Measurement Technology was established at the University of Gävle (HIG). The long term objectives of the centre are to establish world leading research in the area of RF Measurement Technology, support education of radio engineers for local, national and international radio companies at HIG, become a natural collaboration partner for leading industry companies and universities and to support local and national small and middle sized companies in the radio business.

    Today the centre has collaboration with more than 15 national and international companies within 3 major projects in the field of RF measurement technology research spanning from power amplifiers and antennas to electromagnetic interference in industrial environments.

    The annual research budget is in the area of 10 MSEK. In addition to the research projects the centre also supports education and collaboration with local industry, high schools and community.

    The centre is located easy to find, well equipped laboratories in Gävle Technology Park, next to the University of Gävle campus.

  • 44.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Belkow, Elena
    Eklund, Lars
    Landmark, Urban
    Wirdemark, Per
    Verifying 3G License Requirements: some Preliminary Swedish Results2008In: The 68th IEEE Vehicular Technology Conference: VTC2008-Fall, 2008, p. 1-4Conference paper (Other academic)
    Abstract [en]

    In the year 2000, the Swedish Telecom regulator “Post&Telestyrelsen” (PTS) granted in a “beauty contest” four licenses for operation of 3G mobile networks. Through this process, the licensees committed themselves to cover 8.860.000 inhabitants of the Swedish population. In order to verify the coverage and confirm compliance with the license requirements, PTS, developed a test procedure in close collaboration with the licensees.

    The present paper gives an overview of the considerations behind the design of the test method and presents some preliminary results. Today all Swedish 3G operators comply with the licence requirement and it is concluded that a method for verifying the requirement accepted by the licensees is an important tool for successful licensing of spectrum and fulfilment of licensing obligations.

  • 45.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Eklund, Lars
    Karlsson, Bo
    Lindmark, Björn
    Ribbenfjärd, David
    Wirdemark, Per
    Verifying 3G licence requirements when every dB is worth a billion2006In: First European Conference on Antennas & Propagation: EuCAP 2006 / [ed] H. Lacoste & L. Ouwehand, 2006, p. 1-4Conference paper (Refereed)
    Abstract [en]

    In the year 2000, the Swedish Telecom regulator: “Post&Telestyrelsen”, PTS, granted in a “beauty contest” four licenses for operations of 3G systems. To verify the coverage and the license requirements, PTS, has developed a test procedure where the field strength of the primary Common Pilot Channel, CPICH, is measured in a drive test. Designing such a test constitutes a number of challenges mainly due to the fact that in 3G the accuracy in the measurement needs to be extremely high since even a small systematic error of ~1dB could in Sweden have the consequence that each operator would have to build an extra +1000 sites at a staggering cost of ~1billion SEK!

    The present paper gives an overview of the considerations behind the design of the test method used for verification of the 3G licence requirements in Sweden.

  • 46.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Klahr, Stefan
    Ett ödesval för regionen2009In: Gefle Dagblad, Vol. 6 februariArticle in journal (Other (popular science, discussion, etc.))
  • 47.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindmark, Björn
    Base station antennas for mobile communications2007In: 2007 IEEE International Symposium on Antennas and Propagation: Short Courses & Workshops, 2007Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    This course gives the participants a general overview of the application, implementation and design of current and future base station antennas for mobile communications. It is aimed at microwave, RF- and antenna engineers in the wireless area, but also useful for researchers looking for relevant research topics and system engineers needing a deeper understanding of the antenna component of their system. The course explains underlying theoretical and practical implementation aspects of base station antennas in mobile communication networks of today and the future.

    The course is divided into three main parts:

    (i) System Aspects,

    (ii) BTS Antenna Design,

    (iii) Diversity and MIMO

    In the first part the fundamental parameters of a base station antenna are discussed in the context of radio network design. In particular we discuss parameters such as gain, radiation patterns, frequency bands and power handling and put them in the context of cell planning, propagation and capacity.

    In the second part a general overview of base station antenna design is given. In particular the design aspects of radiators, feed networks and reflectors are discussed. Furthermore, a general discussion of array synthesis for base station antennas is given.

    In the final part of the course we give an overview of the underlying theory of diversity and MIMO systems. In particular we discuss the requirements that these systems put on the base station antennas in order to be able to deliver the data rates expected from WiMAX and the long term evolution of 3G systems.

  • 48.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindmark, Björn
    The evolution of base station antennas for mobile communications2007In: International Conference on Electromagnetics in Advanced Applications: ICEAA 07, 2007Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    During the last two decades, mobile telephony has virtually exploded around the world. Whereas fixed telephony has merely around 800 milion phone lines globally, cellular mobile telephony has today close to 4 bilion subscribers less than 20 years after the introduction of digital mobile telephony!

    In the centre of a mobile cell is the base station antenna whose vertical and horizontal beam pattern creates the borders. The first base station antennas deployed for cellular communications were omni-directional in the horizontal plane. These antennas are typically based on stacked circular dipole elements fed by a series feed network. However, as the need for capacity increased more radio channels were being used and the radio networks soon reconfigured to 3 sector systems. The base station antennas in these type of systems typically has half power beam widths in the horizontal plane of around 65 degrees and the elements are fed by corporate feed networks.

    Through the choice of antenna length and the selection of vertical element positions and excitations a broad range of antenna gains and vertical beam patterns can be achieved. We show that for a linear array the gain is mainly determined by the vertical and horizontal beam widths but reduced by losses in the feed network. The electrical down tilt is needed to provide good coverage within the desired cell and is preferred to mechanical down tilt as it is independent of horizontal angle. Remotely adjustable electrical down tilt is also available today and an important cost saver during the expansion part of a network. As we will see, system requirements on reduced channel interferencemlead to a simple expression for the necessary phase shift in such an array.

    Due to the rapid increase in subscribers it was soon realized by the regulators around the world that one frequency band for digital mobile communications was not enough to provide the capacity needed. Therefore, in the mid 90-ties second frequency bands were introduced in both North America and Europe. Since operators are not keen to put up bigger towers and more antennas, ´this development called for dual-band antennas. The introduction of the UMTS band in the beginning of this millennium of course then called for triple band functionality!

    Traditionally the diversity is achieved by using two receive antenna branches separated in space. In mobile phone networks, all base stations for macro cellular communications incorporate diversity on the up-link. Otherwise it would be virtually impossible to communicate with a low power mobile over the rapidly fading channel. Since space diversity uses two horizontally separate antennas positioned about 20 wavelengths apart it become soon of interest for the operators to incorporate polarization diversity. With polarization diversity only one dual polarized antenna is used for each sector at the base. In order to ensure good polarization diversity it is necessary and sufficient to have symmetrical patterns with equal power in horizontal and vertical polarization.

    In 3G it is of great interest to strengthen the up- and down-links in order to be able to increase the data rates from today’s 16kbit/s (voice) to a wireless broadband of around 10Mbits/s. However, in the Long Term Evolution of 3G, LTE, data rates of up to and around 100MBits/s are expected. In order accomplish this diversity at the base station will not be enough but complemented by multiple branch reception and transmission at both the base station and the mobile terminal (Multiple-Input-Multiple-Output, MIMO systems). For such arrays it is of interest to reduce the mutual coupling between elements. Although the mutual coupling could be compensated for by perfect channel estimation it is still of interest to reduce the coupling in practice in order to be able to handle the mismatch loss. In order to do so the use of e.g. corrugations, hard and soft surfaces as well as Electronic Band Gap, EBG materials for the inclusion into the antenna structure has been studied.

    In conclusion we find that the base station antenna has developed dramatically during the last two decades and base station antenna technology may become a key enabler for the Long Term Evolution of 3G.

  • 49.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Smith, Gregory
    Shared Networks: Making Wireless Communications Affordable2005In: IEEE wireless communications, ISSN 1536-1284, E-ISSN 1558-0687, Vol. 12, no 2, p. 78-85Article in journal (Refereed)
    Abstract [en]

    In the wake of the substantial financial commitments incurred by European and other UMTS network operators in the form of licence fees, licensees have turned to network sharing as a means of reducing the capital requirements needed to bring 3G services to market. The reception from European regulators has been mixed, due to concerns that this inhibits competition, slow buildout, or otherwise result in reduced consumer benefits. The authors believe that the generic product life cycle model provides insights that indicate that network sharing, within an appropriately constructed regulatory framework, is not a threat to vigorous competition in the 3G industry, and in fact is one of the keys to stimulating the development of advanced, ubiquitous, affordable services.

  • 50.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Smith, Gregory
    Shared Networks: More than making wireless communication affordable2005In: Vehicular Technology Conference, 2005: VTC 2005-Spring., 2005, p. 2984-2988Conference paper (Refereed)
    Abstract [en]

    In the wake of the substantial financial commitments incurred by European and other UMTS network operators in the form of license fees, licensees have turned to network sharing as a means of reducing the capital requirements needed to bring 3G services to market. The reception from European regulators has been mixed, due to concerns that this inhibits competition, slow build-out, or otherwise result in reduced consumer benefits. The authors believe that the generic product life-cycle model provides insights that indicate that network sharing, within an appropriately constructed regulatory framework, is not a threat to vigorous competition in the 3G industry, and in fact, is one of the keys to stimulating the development of advanced, ubiquitous, affordable services.

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