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574 Uppsatser om Temperature gradient - Sida 24 av 39
Trä och fukt ? Mätmetoder för fuktrelaterade dimensionsförändringar hos trä och deras användbarhet, med två fallstudier inom konservering
This thesis deals with different methods for measuring moisture-related dimensional changes ofwood. Typically relative humidity is measured to determine if the ambient climate around anobject is harmful to it or not. Values between 40 to 65% RH are recommended for hygroscopicmaterials. To know how a wooden object actually reacts to changes in the surroundingenvironment requires methods that involve the object itself. Because of the wood anisotropy,differences in wood structure, finishes and other restraints, it is not always possible to predict themovements.This paper addresses various measurement methods, primarily methods that have been testedin the field of conservation, with examples of their use.
Kartläggning av energianvändning under byggfasen vid nyproduktion av flerbostadshus
The energy consumption in the sectors of residential and public buildings is 40 % of the total energy consumption in Sweden. The main part, 85 %, of the energy use in these sectors is for operation of the buildings. The rest is used in the building process. When energy-efficiency measures are taken the energy use during the operation time decreases and the fraction of energy consumption during the building time increases. This project is carried out in cooperation with JM AB and concerns the energy use during the building time of production of blocks of flats at the building site.The main part of the electricity that is used during the production of apartment buildings goes into the heating of portacabins and illumination of the building during the construction phase.
Spelutveckling och lansering av applikation till Android
For several years Uppsala University together with several companies has been involved in a WISENET project aimed at improving railway transport security. By placing a sensor system near the wheels of each wagon, the temperature of the bearings can be measured and transmitted to a collector placed centrally on the wagon. This in turn transmits the collected data to RFID receivers placed intermittently along the railway.As the signals are transmitted wirelessly, problems may occur as the antennas get dirty or coated with ice and snow. To determine the effects of these coatings, several tests were performed examining the reflection coefficient S11, the impedance Z11 and the efficiency eta of an antenna, and how they varied when various coatings were placed over the antenna. Examined coatings were ice, snow and water to determine the effects of weather, and various metal-based coatings: powdered iron both pure and partially oxidized, and iron ore granules.
Galactose in dairy products
Milk and milk consumption has been subject of discussion for a long time, and is still a hot topic. Recently, as study was published that observed a correlation between milk intake and increased risk of fractures and mortality. The authors proposed the milk?s content of D-galactose as the possible mechanism, since D-galactose is used indicated ageing in animal models. Therefore, this study aims to develop a method to determine the amount of galactose, glucose and lactose in milk and fermented milk and apply it on to dairy products on the Swedish market.
Fuktomlagringar i välisolerade ytterväggar : En undersökning för att fastställa en rimlig inbyggnadsfuktkvoti träreglar med fuktsimuleringsprogrammet Wufi 2D
To save energy it?s popular to build houses with low energy loss. In these houses the walls are keeping a lower temperature in the external side which leads to a higher relative humidity. In addition more material, such as wood studs, are used which means that there is more moisture to dry. More moisture in combination with higher relative humidity may pose a higher risk of microbial growth.
US foreign corrupt practices act i svenska börsnoterade storföretag
Brämhults Juice AB is one of Sweden?s leading producers of fresh fruit juices and drinks. The fruit drinks last 3 days once opened and when stored in a refrigerator kept at 7°C. Since factors that shorten the drinks? best before date are usually not noticed until the entire batch has expired, it would be advantageous to find a way to accelerate the drinks? natural deterioration, so that an unusal short best before date is noticed before more products are shipped off to the stores.
Termoelektrisk lagring i system med fjärrvärmeproduktion
With increased deployment ofintermittent renewable energy, such aswind and solar power, energy storagebecomes necessary to help reduceproduction peaks. Thermoelectric EnergyStorage is a method still in researchphase, which stores electricity in hotwater at a temperature of 120 ° C. Thisthesis aims to examine whether theThermoelectric Energy Storage would bepossible to integrate into existingpower generation such as a combined heatand power plant, and how the technologypotentially could function in theelectricity market. ThermoelectricEnergy Storage consists of a chargingprocess and a discharging process, bothoperating by the working fluid CO2. Toincrease the efficiency of theThermoelectric Energy Storage, wasteheat from the district heating networkis integrated.A model of the Thermoelectric EnergyStorage has been developed and it wascalculated by thermodynamic propertiesof the working fluid, CO2, in thevarious process steps.
Rökgaskondensering och skrubber till vedeldade villapannor :
This paper deals with the opportunities for the technique of condensation, for wood fired household heaters, on the Swedish market. In this project the condenser is preceded by a scrubber and both energy exchange and separation of unburnt particles have been studied.
The facility studied is connected to a wood stove at 30 kW. The tests would show that the effect from the stove never reached above 16 kW. This might be a result of the low temperature of the water going into the stove, from the condenser. In addition to this the wood was not of highest quality and the stove could have needed some maintenance before the tests.
Experimentell konstruktion av pickupsystem anpassat för trummor med hjälp av MATLAB
For several years Uppsala University together with several companies has been involved in a WISENET project aimed at improving railway transport security. By placing a sensor system near the wheels of each wagon, the temperature of the bearings can be measured and transmitted to a collector placed centrally on the wagon. This in turn transmits the collected data to RFID receivers placed intermittently along the railway.As the signals are transmitted wirelessly, problems may occur as the antennas get dirty or coated with ice and snow. To determine the effects of these coatings, several tests were performed examining the reflection coefficient S11, the impedance Z11 and the efficiency eta of an antenna, and how they varied when various coatings were placed over the antenna. Examined coatings were ice, snow and water to determine the effects of weather, and various metal-based coatings: powdered iron both pure and partially oxidized, and iron ore granules.
Utveckling av HPLC-metoder för kvantifiering av nyckelkomponenter i en villkorad emulsion
Traditionally, rolling mills use emulsions based on a mixture of oil and water for lubrication. Since two years ago SAPA has been using (instead of oil) a synthetic lubricant so called conditional emulsion for hot-rolling of aluminum. This lubricant is water based and homogenous at ambient temperature, but switches to a two-phase system at heating above the cloud point.This project aims to validate and if necessary modify an existing HPLC method for quantifying two out of three key components (A, B and C) in the conditional emulsion. Attempts to develop a method to quantify the pH adjusting components, X and Y were also made. These two methods are required to optimize the lubricant.Due to the complexity of the components, it has been difficult to present a method for quantification, and HPLC with ELS detection was chosen after a long series of trials.
Alpin permafrost i Kebnekaisefjällen : Modellering med logistisk regression och BTS-data
Denna studie är ett försök att modellera den alpina permafrostens utbredning inom Kebnekaisemassivet i norra Lappland. En karta som visar sannolikheten för permafrostens utbredning har skapats med hjälp av data från Bottom Temperature of Snow cover (BTS) - mätningar samt statistisk modellering genom logistisk regression.Fältstudien genomfördes under mars till april 2011 med totalt 56 BTS-punkter från 1073 till 1805 m.ö.h. Permafrostförekomsten bestämdes vara en funktion av höjden. För att utreda detta användes stepwise selection som är en metod för att identifiera statistiskt signifikanta variabler gentemot en beroende variabel. De andra parametrarna som testades var topografins sluttningsgradient, riktningen av den maximala lutningen och den potentiella solinstrålningen.
Energibalansberäkning
Abstrakt - As energy prices rise, energy-saving in buildings is becoming increasingly important. By applying different construction and installation technologies, to new buildings the energy consumption can be reduced effectively, compared to similar existing buildings. These technical measures are often an investment in the long term and will reduce energy costs significantly. The purpose of this report is to show how to reduce energy consumption in a small house. It is presented in this report that both building's technical saving arrangements (the sealing of a building) and an installation technical arrangement (changing from the F-system to the FTX-system) would reduce energy consumption in newly built detached houses, if compared with a similar existing house but without these technical measures. The report presents also detailed calculations showing how much energy an existing 2-storey house, built in the year 2007 in Eskilstuna, consumes and how much energy would be saved if these corrective measures were applied to a new building. It is also reported how much money would be saved each year over a 10 year period if the measures were applied. The results show that both solutions are a good investment in the reduction of energy consumption and hence the cost involved. Keywords: energy, heat energy, infiltration, FTX-system, free temperature effectively. .
Klimatkabinett : Komponenter och konstruktion
This report describes the construction of a climate-cabinet for testing of HV-cards (High Voltage) produced at VG Scienta. The main part of the report describes all the different components of the cabinet. The most important parts are a PID regulator from Eurotherm model 2408, a solid state contactor (SSC), a thermocouple, a finned resistor from DBK and different fans. The report even includes the connection between components by cable wiring, isolation, grounding, fuses and shaping of metal goods.As the cabinet also communicates with a computer, the report includes the solution of the data communication using the software iTools from Eurotherm. The communication part includes information about a converter that converts EIA422 to USB.The cabinet was produced at a company, called VG Scienta, in Uppsala during the spring 2010.
Konstruktion av formkropp pa JAS 39 E/F Gripen
The aim of this work is to develop new conceptual designs for the fairings that are situated between the fin and the rear fuselage on the new version of the JAS 39 Gripen aircraft, called the Gripen E/F. The designs presented should show a profit in the form of lower weight. To achieve weight loss, the possibilities of using other construction materials other than those which are available at Saab today were studied. Therefore, a material survey was carried out in which the market for modern construction materials was studied to get an idea of today?s level of technology.
Brandskydd av stålkonstruktioner : Lathund för brandskyddsdimensionering av stålprofiler
This bachelor thesis covers fire protection methods of structural steel and the aim is to develop an information tool designed for inexperienced structural engineers. The information tool covers basic fire protection methods and the general way to produce a fire resistance for structural steel. The layout of this information tool is a simple folder that contains information about the most important steps when producing fire protection for a steel structure.The thesis starts with a general overview of the fire protection needed in buildings to fulfill national legislative and regulatory requirements. To get an understanding of how steel components behave during the influence of fire, a brief overview is presented of the material properties of steel. This chapter also contains a review of previous research in the area.