10 resultados para Economical

em Dalarna University College Electronic Archive


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The purpose of this paper is to make quantitative and qualitative analysis of foreign citizens who may participate on the Swedish labor market (in text refers to as ‘immigrants’). This research covers the period 1973-2005 and gives prediction figures of immigrant population, age and gender structure, and education attainment in 2010. To cope with data regarding immigrants from different countries, the population was divided into six groups. The main chapter is divided into two parts. The first part specifies division of immigrants into groups by country of origin according to geographical, ethnical, economical and historical criteria. Brief characteristics and geographic position, dynamic and structure description were given for each group; historical review explain rapid changes in immigrant population. Statistical models for description and estimation future population were given. The second part specifies education and qualification level of the immigrants according to international and Swedish standards. Models for estimating age and gender structure, level of education and professional orientation of immigrants in different groups are given. Inferences were made regarding ethnic, gender and education structure of immigrants; the distribution of immigrants among Swedish counties is given. Discussion part presents the results of the research, gives perspectives for the future brief evaluation of the role of immigrants on the Swedish labor market.

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Snow cleaning is one of the important tasks in the winter time in Sweden. Every year government spends huge amount money for snow cleaning purpose. In this thesis we generate a shortest road network of the city and put the depots in different place of the city for snow cleaning. We generate shortest road network using minimum spanning tree algorithm and find the depots position using greedy heuristic. When snow is falling, vehicles start work from the depots and clean the snow all the road network of the city. We generate two types of model. Models are economic model and efficient model. Economic model provide good economical solution of the problem and it use less number of vehicles. Efficient model generate good efficient solution and it take less amount of time to clean the entire road network.

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PV-Wind-Hybrid systems for stand-alone applications have the potential to be more cost efficient compared to PV-alone systems. The two energy sources can, to some extent, compensate each others minima. The combination of solar and wind should be especially favorable for locations at high latitudes such as Sweden with a very uneven distribution of solar radiation during the year. In this article PV-Wind-Hybrid systems have been studied for 11 locations in Sweden. These systems supply the household electricity for single family houses. The aim was to evaluate the system costs, the cost of energy generated by the PV-Wind-Hybrid systems, the effect of the load size and to what extent the combination of these two energy sources can reduce the costs compared to a PV-alone system. The study has been performed with the simulation tool HOMER developed by the National Renewable Energy Laboratory (NREL) for techno-economical feasibility studies of hybrid systems. The results from HOMER show that the net present costs (NPC) for a hybrid system designed for an annual load of 6000 kWh with a capacity shortage of 10% will vary between $48,000 and $87,000. Sizing the system for a load of 1800 kWh/year will give a NPC of $17,000 for the best and $33,000 for the worst location. PV-Wind-Hybrid systems are for all locations more cost effective compared to PV-alone systems. Using a Hybrid system is reducing the NPC for Borlänge by 36% and for Lund by 64%. The cost per kWh electricity varies between $1.4 for the worst location and $0.9 for the best location if a PV-Wind-Hybrid system is used.

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To integrate study visits to different workplaces in higher education implies important benefits for the course quality. The study visit gives the students a better understanding for the real situations they will meet in working life. However for practical and economical reasons is that not always possible. The purpose of this project is to create a virtual company that shall replace the real one for study visits. The goal is to create a realistic picture and that intended use of it can come as close as possible to a real study visit. It is also important to facilitate linking theory and practice. The virtual company is built up by pictures, videos and text. All material is made available on a web page and when entering the students will meet a layout of the company. From that position is it possible to walk around and look at videos from different workstations. Besides that can they also listen to interviews with managers and representatives of staff as well as reading reports concerning productivity and the work environment. The focus of the study visit is work sciences, therefore the material also include some visualized information about work hazards. On the web page there are also a number of tasks for the students to carry out. Until the autumn 2011, 132 students at Dalarna University have visited and produced reports from the virtual company. They were studying in programs for mechanical engineering, production technicians and human resource management. An evaluation among some ten students showed that the study visit to the virtual company is flexible in time and effective, but that students wish to have even more detailed information about the company. Experiences from four years of use in a number of classes show that the concept is worth further development. Furthermore with production of new material the concept is likely to be applicable for other purposes.

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This thesis examines prerequisites for wind power diffusion in a county in Sweden that quite recently was concidered to be of interest for electricty production from renewable energy sources. Three different municipalities: Falun, Mora and Orsa in the county of Dalarna are highlighted.  Their view on permitting processes of wind power installations are investigated. Other actors, such as exploiters and local citizens are also being analysed. This study shows that the local acceptance was very high when the first wind power parks were built, much thanks to local politicians and local citizens. For the politicians the wind power symbolised a key to a better green society, for the local citizens the wind power meant some economical advantages. The first wind power parks were localised to areas because of good wind conditions and social factors, especially from local communities. However, results from this study shows that the acceptance for wind power the last few years, in generel, has decreased.  The local authorities have also been conscious of some negative consequenses from already built wind power parks.  As a response they started to add planning tools to the permitting process.

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The aim of this study was to investigate how electricallyheated houses can be converted to using wood pellet and solarheating. There are a large number of wood pellet stoves on themarket. Many stoves have a water jacket, which gives anopportunity to distribute the heat to domestic hot water and aradiator heating system. Three typical Swedish houses with electric resistanceheating have been studied. Fourteen different system conceptsusing wood pellet stoves and solar heating systems have beenevaluated. The systems and the houses have been simulated indetail using TRNSYS. The houses have been divided in up to 10different zones and heat transfer by air circulation throughdoorways and open doors have been simulated. The pellet stoveswere simulated using a recently developed TRNSYS component,which models the start- and stop phases, emissions and thedynamic behaviour of the stoves. The model also calculates theCO-emissions. Simulations were made with one stove without awater jacket and two stoves with different fractions of thegenerated heat distributed in the water circuit. Simulations show that the electricity savings using a pelletstove are greatly affected by the house plan, the systemchoice, if the internal doors are open or closed and thedesired level of comfort. Installing a stove with awater-jacket connected to a radiator system and a hot waterstorage has the advantage that heat can be transferred todomestic hot water and be distributed to other rooms. Suchsystems lead to greater electricity savings, especially inhouses having a traditional layout. It was found that not allrooms needed radiators and that it was more effective in mostcases t use a stove with a higher fraction of the heatdistributed by the water circuit. The economic investigation shows that installing a woodpellet stove without a water jacket gives the lowest totalenergy- and capital costs in the house with an open plan (fortoday's energy prices and the simulated comfort criteria). Inthe houses with a traditional layout a pellet stove givesslightly higher costs than the reference house having onlyelectrical resistance heating due to the fact that less heatingcan be replaced. The concepts including stoves with a waterjacket all give higher costs than the reference system, but theconcept closest to be economical is a system with a bufferstore, a stove with a high fraction of the heat distributed bythe water circuit, a new water radiator heating system and asolar collector. Losses from stoves can be divided into: flue gas lossesincluding leakage air flow when the stove is not in operation;losses during start and stop phases; and losses due to a highair factor. An increased efficiency of the stoves is importantboth from a private economical point of view, but also from theperspective that there can be a lack of bio fuel in the nearfuture also in Sweden. From this point of view it is alsoimportant to utilize as much solar heat as possible. Theutilization of solar heat is low in the simulated systems,depending on the lack of space for a large buffer store. The simulations have shown that the annual efficiency ismuch lower that the nominal efficiency at full power. Thesimulations have also shown that changing the control principlefor the stove can improve efficiency and reduce theCO-emissions. Today's most common control principle for stovesis the on/off control, which results in many starts and stopsand thereby high CO-emissions. A more advanced control varyingthe heating rate from maximum to minimum to keep a constantroom temperature reduces the number of starts and stops andthereby the emissions. Also the efficiency can be higher withsuch a control, and the room temperature will be kept at a moreconstant temperature providing a higher comfort.

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In Sweden, there are about 0.5 million single-family houses that are heated by electricity alone, and rising electricity costs force the conversion to other heating sources such as heat pumps and wood pellet heating systems. Pellet heating systems for single-family houses are currently a strongly growing market. Future lack of wood fuels is possible even in Sweden, and combining wood pellet heating with solar heating will help to save the bio-fuel resources. The objectives of this thesis are to investigate how the electrically heated single-family houses can be converted to pellet and solar heating systems, and how the annual efficiency and solar gains can be increased in such systems. The possible reduction of CO-emissions by combining pellet heating with solar heating has also been investigated. Systems with pellet stoves (both with and without a water jacket), pellet boilers and solar heating have been simulated. Different system concepts have been compared in order to investigate the most promising solutions. Modifications in system design and control strategies have been carried out in order to increase the system efficiency and the solar gains. Possibilities for increasing the solar gains have been limited to investigation of DHW-units for hot water production and the use of hot water for heating of dishwashers and washing machines via a heat exchanger instead of electricity (heat-fed appliances). Computer models of pellet stoves, boilers, DHW-units and heat-fed appliances have been developed and the parameters for the models have been identified from measurements on real components. The conformity between the models and the measurements has been checked. The systems with wood pellet stoves have been simulated in three different multi-zone buildings, simulated in detail with heat distribution through door openings between the zones. For the other simulations, either a single-zone house model or a load file has been used. Simulations were carried out for Stockholm, Sweden, but for the simulations with heat-fed machines also for Miami, USA. The foremost result of this thesis is the increased understanding of the dynamic operation of combined pellet and solar heating systems for single-family houses. The results show that electricity savings and annual system efficiency is strongly affected by the system design and the control strategy. Large reductions in pellet consumption are possible by combining pellet boilers with solar heating (a reduction larger than the solar gains if the system is properly designed). In addition, large reductions in carbon monoxide emissions are possible. To achieve these reductions it is required that the hot water production and the connection of the radiator circuit is moved to a well insulated, solar heated buffer store so that the boiler can be turned off during the periods when the solar collectors cover the heating demand. The amount of electricity replaced using systems with pellet stoves is very dependant on the house plan, the system design, if internal doors are open or closed and the comfort requirements. Proper system design and control strategies are crucial to obtain high electricity savings and high comfort with pellet stove systems. The investigated technologies for increasing the solar gains (DHW-units and heat-fed appliances) significantly increase the solar gains, but for the heat-fed appliances the market introduction is difficult due to the limited financial savings and the need for a new heat distribution system. The applications closest to market introduction could be for communal laundries and for use in sunny climates where the dominating part of the heat can be covered by solar heating. The DHW-unit is economical but competes with the internal finned-tube heat exchanger which is the totally dominating technology for hot water preparation in solar combisystems for single-family houses.

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What is academic quality? On the decline of academic autonomy In light of the transformations that universities currently undergo, with Bologna as a keyword, the following questions are put: What ideals lie behind the assessment of academic “excellence” and “quality”? What agents have the ability to define what is good science and education today? These questions are approached through Pierre Bourdieus concept of field. Looking at the development the last decade, traditional academic values, such as the ideal of universal knowledge as (personal and collective) enrichment and the intellectual independence “of all political authority and economic power”, as stated in the Magna Charta Universitatum, seem to have emerged into the shadow of employability, knowledge control, competitiveness, and economic benefit. In connection with the formation of concepts such as “the knowledge society” and “knowledge based economies” the university has received a somewhat different and more central role in society. The university has come to take the role more of a knowledge producing enterprise clearly directed towards the surrounding society. There are higher demands on academic knowledge to contribute to economic, regional or national development and competitiveness. When the university is regarded as a knowledge company whose task is to accoun tfor the requests of the students, the labour market, and the business world it undertakes to follow trends and short term social phases rather than to critically examine them, which has been a traditional task for the university. If the academic work is guided by the market economical principle, that the client requests decide what quality is, instead of the experts on the academic field themselves (i.e. the scientists,) it is obviously not scientific ideals that constitute the criteria for what is good science and education.

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Background. High quality maternal health care is an important tool to reduce maternal and neonatal mortality. Services offered should be evidence based and adapted to the local setting. This qualitative descriptive study explored the perspectives and experiences of midwives, assistant physicians and medical doctors on the content and quality of maternal health care in rural Vietnam. Method. The study was performed in a rural district in northern Vietnam. Four focus group discussions with health care professionals at primary health care level were conducted. The data was analysed using qualitative manifest and latent content analysis. Result. Two main themes emerged: "Contextual conditions for maternal health care" and "Balancing between possibilities and constraints". Contextual conditions influenced both pregnant women's use of maternal health care and health care professionals' performance. The study participants stated that women's uses of maternal health care were influenced by economical constraints and cultural norms that impeded their autonomy in relation to childbearing. Structural constraints within the health care system included inadequate financing of the primary health care, resulting in lack of human resources, professional re-training and adequate equipment. Conclusion. Contextual conditions strongly influenced the performance and interaction between pregnant women and health care professionals within antenatal care and delivery care in a rural district of Vietnam. Although Vietnam is performing comparatively well in terms of low maternal and child mortality figures, this study revealed midwives' and other health care professionals' perceived difficulties in their daily work. It seemed maternal health care was under-resourced in terms of staff, equipment and continuing education activities. The cultural setting in Vietnam constituting a strong patriarchal society and prevailing Confucian norms limits women's autonomy and reduce their possibility to make independent decisions about their own reproductive health. This issue should be further addressed by policy-makers. Strategies to reduce inequities in maternal health care for pregnant women are needed. The quality of client-provider interaction and management of pregnancy may be strengthened by education, human resources, re-training and provision of essential equipment.

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Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling. This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period. Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.