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286 Uppsatser om Thermal radiation - Sida 9 av 20

Lagring av kyla i bergrum : Undersökning av ett nedlagt oljebergrum

This thesis considers the use of an oldrock cavern as thermal energy storage.With a large system of differentchillers a model was created to find anappropriate future system. There aremainly two trajectories to take. Eitheran installation of chillers needs to bemade or the rock cavern can be used tomeet the future demand of districtcooling in Solna, Sweden. Additionallythis thesis investigates the possibleuse of different techniques to utilizethe phase change energy of water.Simulation shows that it?s possible toutilize the phase-change energy of afluid; however it?s not economicallyfeasible due to the thermodynamiceffects on the Carnot cycle.

Förstudie för kvalitetssäkringav glidande förband vid Hissmoforsvattenkraftsstation : -Specifikt för aggregat G6 och G7

Jämtkraft AB which is a power production company in Sweden has bought two newhydro power units to their station in Hissmofors. The two new generators are using aconcept with sliding stator feet to handle the thermal expansion.The concept with sliding stator feet on hydro electric generators has not beenworking satisfactory on many hydro power stations in Sweden and has caused a lot ofcosts due to long downtimes.The new station in Hissmofors is very important for Jämtkraft AB, and therefore theywant to know how to make sure that the sliding stator feet are working as theyshould. According to theories and a simplified model of the generator the stator feetdisplacement should be around 1 -1,6 mm.The generators are delivered with a surveillance system that will measure thedisplacement of the sliding stator feet. The signal from the system isn?t accessible forJämtkraft AB but it will alarm when the sliding stator feet are malfunctioning.To secure the function of the sliding feet a logger for the surveillance system or adifferent measurement system must be used; if both systems are used Jämtkraft cansecure the function of the surveillance system..

Miljöcertifiering av ett byggnadsminne

Samtidigt som debatten kring jordens klimatförändring är i full gång har intresset för att miljöcertifiera byggnader vuxit oerhört. För fastighetsägare är det en möjlighet att bevisa för sina hyresgäster och köpare att byggnaden är hållbar. Är en byggnad miljöcertifierad har en oberoende part intygat att den uppfyller en nivå av hållbarhet som bestäms utifrån standardiserade kriterier. Fastighetsägaren kan alltså använda certifikatet i marknadsföringssyfte.Den här studien undersökte om en byggnad som är byggnadsminnesförklarad kan miljöcertifieras med Miljöbyggnad. Målet var att hitta kostnadseffektiva lösningar för att uppfylla de miljöcertifieringskriterier som eventuellt inte uppfylls idag.

Småhusutformning och solenergiutnyttjande

This paper goes through solar energy and what uses it has. It is also a guide in the choice of solar collectors forthe real estate that I have drawn for the thesis work.Solar energy is a renewable source of energy from the Sun's light. Energy can be used to produce both heat andelectricity through solar collectors and solar cells. Some of the benefits of solar energy is that it is completely freeto extract, environmentally friendly and virtually maintenance-free. Disadvantages are that the technology isexpensive, does not cover the entire energy needs and takes a long time until it pays.

Validering av glidande statorfötter på Hissmofors G6 och G7

Jämtkraft AB has recently modernized its hydropower station at Hissmofors by replacing four older worn out units with two new units. The generators uses a concept with sliding stator feet to deal with the thermal movements that occur in the stator during operation when the unit is operating intermittently. At other sites, this method revealed shortcomings in the reliability. This has made Jämtkraft AB feel uncertainty about its function and therefore want to investigate it during an early stage. The generators have a built-in monitoring system for the sliding stator feet and by using data from there the function of the sliding stator feet has been investigated. The study focused on how the different stator feet move relative to each other and how the eccentricity and deviation from roundness changed during operation. The results show that there are several indications that the function of the sliding stator feet is not satisfactory.

Design of a Direct-conversion Radio Receiver Front-end in CMOS Technology

In this Master's thesis, a direct-conversion receiver front-end has been designed in a 0.18um CMOS technology. Direct-conversion receivers (DCR) have obvious advantages over the heterodyne counterpart. Since the intermediate frequency (IF) is zero, the problem of image is circumvented. As a result, no front-end image reject filter is required and the channel selection requires only a low-pass filter, which makes it easy to integrate directly on chip. However, the DCR also suffers from several drawbacks such as extreme sensitivity to DC offsets, 1/f noise, local oscillator (LO) leakage/radiation, front-end nonlinearity and I/Q mismatch.

Bremsningens effekter hos häst : utvärderat med hjälp av termografi, hormonanalyser och hematologi

Twitching is frequently used in horse management because of its sedating and pain-relieving effects. In this study, the effects on the horse?s nervous system by twitching were investigated by thermography of the skin temperature. The temperature is regulated by the sympathetic nervous system through postganglionic sfincters at the capillaries of the skin. The effects on the endocrine activity have also been studied by the measuring of ACTH and cortisol in blood plasma.

En studie av metodbyte vid sintring av hårdmetaller till mikrovågsintring samt dess ekonomiska fördelar : Självständigt arbete i teknisk fysik med materialvetenskap & Självständigt arbete i kemiteknik

The aim with this study was to investigate the effects a change of manufacturing process would have on the mechanical properties of drill bits made of a WC/Co composite used for stone cutting. The method used today is sintering, where the material is heated in a conventional sintering oven. The other method was microwave sintering, where the material is heated by radiation in the microwave region. Also an investigation of the manufacturing cost were made.The main difference between the two heating methods is that the conventional way is a rather slow process and the microwave method is very fast. The material is also heated homogeniously in the method with mirowaves, aposed to the case with the conventional sintering where the material is heated from the outside in.This makes the material harder and more wear resistent.

Påverkan av skogsbrand på litiska arkeologiska fynd ? experimentell simulering av brand

This is a paper about the effects from smoldering fire on lithic objects from an archaeological view. The introduction gives the background to this paper, a short orientation to forest wildfires and why the work is limited to: flint, quartz, quartzite and slate. Material and methods describes the stone materials and the setup that was used in the temperature logged tests with three replications for each type of material. The fuel in the burnings was peat on a bottom of sand. Flint showed a more drastic effect from heat compared with the other materials. Slate seems to have greater tendencies to change to darker colour and luster at lower temperatures than the other materials.

Gotland ponies on extensive pastures ? a welfare assessment

Swedish farmers have the possibility to be subsidized by EU rural development programme for grazing animals on pastures to promote the biodiversity of flora and fauna. The environmental remedy sometimes does not allow supplementary feed and at the same time the Swedish Animal Welfare Act and the Swedish Agricultural Board?s regulations for animal welfare and protection states that animals, in this case horses, shall be fed with food of good quality and adapted for the species. The regulations also state that they should have an individual feeding regime that enables them to maintain a normal body condition. The aim with this master thesis has been to investigate if it is possible to keep Gotland ponies on extensive pastures, during late spring and summer and still maintain animal welfare. The horses were assessed every fourth week using a welfare assessment protocol developed in line with the Welfare Quality® project (submitted, Viksten et al) where physical, behavioural and resourcebased parameters were observed. Twelve one-year old stallions of the breed Gotland ponies purchased from different breeders were used in the study.

Energiåtervinning från gjuteriprocess till fastighet, undersökning för ökat utnyttjande av spillvärme

This diploma work on D-level is made in cooperation with Varnäsföretagen AB in Eskilstuna. The company performs contract manufactured aluminium goods. This work is a continuation on earlier diploma work in Varnäsföretagen AB. Even if the industry process consumes much energy for melting the aluminium goods, they consume a great amount of oil to warm up the building. The purpose of this work is to examine some places in the building and the process to see how much energy it is possible to recycles to the heating system and reduce the costs for heating.

 En jämförelsestudie av koldioxidsläpp för en byggnad med trä- respektive betongstomme ur ett livscykelperspektiv

The goal with this examination thesis is to investigate the difference in carbon dioxide emissions between a building with a wooden versus concrete carcassing from a life cycle perspective. The huge amounts of carbon dioxide released into air from human activities must be reduced to prevent serious consequences. A way to limit this issue is through performing a comparative study where the result shows which of two products with the same function has the lowest emission of carbon dioxide, whereof the product with the lowest carbon dioxide pollution can be chosen.To be able to perform a study like this an object has been chosen and studies about life cycle analyses have been done. The rental square meter, the thermal conductivity value, the energy requirements and the placement of the building has been set equal in both framework types. There were solely dissimilarities of the two buildings taken into account when this comparison study was performed.The result of the study is that a building constructed with a wooden carcassing has the lowest amount of carbon dioxide emissions.

Närklimat vid avvänjning av smågrisar :

SUMMARY Several studies have shown that weaning pigs are in great need of heat. The reason for this is mainly because the pigs are given very little feed just after weaning. Some of the pig producers of today have tried to get along with these problems by building some kind of hut for the pigs. Some of these pig houses have been included in this study.The study has shown shortcoming functions for the pig cottage. The expected heat increase has not occurred.

Magnetiska egenskaper hos Öje-Diabasen, Dalecarlia

A study of paleomagnetic remanence and anisotropy of magnetic susceptibility (AMS) has been performed on the Öje-Diabase in Dalarna, Sweden, and on basic dikes associated with the alkaliquartzsyenite/granite Noran-pluton in central Sweden. Based on isolation of directions of characteristic magnetization in the basic rocks, a division into three different groups (A,B,C) has been made. Group Aconsists of dolerites of Jotnian origin, both dolerites from the Öje-Diabase and dikes associated with the Noran-pluton are included in this group, making them coeval. Group B is suspected to show a re-magnetization from the later part of the Svekonorwegian orogeny. Group C belongs to the Blekinge-Dalarna-Dolerites (BDD). Thermal demagnetization of dolerites revealed two different types of demagnetization behaviours, one where magnetite clearly was the source of the remanence, and an other with a linear decrease in magnetization intensity. The measurements of magnetic anisotropy reveals a magnetic fabric with an almost horizontal foliation and a lineation that indicates a fairly uniform NNW/ S-SE flow direction of the magma..

Förbehandlingstekniker och LCA för rötning av organiskt avfall : Modellkonstruktion och Utvärdering med ORWARE

The goal of this master thesis project was to develop computer models of some plausiblepretreatment techniques and to assess the potential benefits/costs of using pretreatment andanaerobic digestion for waste management of organic waste from a system perspective. Forthis purpose a computer program called ORWARE has been used. ORWARE (organic wasteresearch) is a program for making life cycle assessments of waste management. As the mainpart of the project work the ORWARE system has been provided with three new models ofpretreatment techniques. The additions consist of: One model of pretreatment with ultrasound,one model of thermal hydrolysis and one model of a screw press.

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