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370 Uppsatser om Numerical simulations - Sida 19 av 25

Spännkraft på bandavskrapare : Utredning och konstruktion

This thesis was performed at Vendig AB which is a company that develops and sells products such as belt scrapers for conveyor. The thesis is divided into two parts, one part where it´s investigated which tension force is required to tighten Vendig AB´s scraper Hampus against the belt in a correct way. The second part is called mechanical design and here a new and more compact tension device is developed.Field studies has been conducted at a couple of Vendig AB´s costumers to get a knowledge base about how Vendig AB´s products are used, how they function and the environment they operate in. During one of the field studies the force between the scraper and the belt was measured. The result from the measurements, together with a report from LKAB [1], were evaluated and summarized in a table.

Utvärdering av försvarsspecifika radiovågformer

To be able to evaluate different radio waveforms in a laboratory environment FOI in Linköping has developed an experimental system for radio communication called Rasmus. The system consists of a transmitter, a channel emulator and a receiver. The transmitter modulates a digital signal to a desired analogue waveform. The channel emulator is used to simulate a real radio channel. The channel emulator distorts the signal by splitting it up in several propagation paths.

En flödesutjämnande driftstrategi för Uppsalas fjärrvärmesystem : En ändrad styrning av framtemperaturen

This thesis examines a possible control strategy to minimize flow fluctuations in Uppsala?s district heating system. High variations in flow rate may lead to complications caused by hydraulic constraints in the district heating system. These complications, such as inadequate pressure and temperature levels, increase the risk of heat delivery failures. It is therefore important to avoid such situations both for the producer and for the customers.Typically, the forward temperature is controlled by using a rough correlation with respect to the outdoor temperature.

Effektiv partiformning : analys och tillämpning på Uppåkra Mekaniska AB

This paper is the result of a case study conducted at Uppåkra Mekaniska AB during the spring of 2006. The task that was presented by Uppåkra was to develop a basis for a decision for the planning activities at the company, so that in the future they can create lot-sizes which are based upon a total cost perspective. Total cost in regards to lot-sizing is defined as the sum of the administrative reordering costs and warehousing cost per stock keeping unit.To collect data a series of interviews and observations were conducted. This data was then used during the lot-sizing simulation and analysis. The 15 units that the simulation was conducted on were grouped into three item classes depending how many different machine setups they required during the production process.

Simulering, ett alternativ inom produktionsplanering?

Typically, when Faurecia in Torsås are planning a new assembly line, one of the steps is to build a full-scale model of the line in card board, a form of mock-up planning. Faurecia has shown interest in finding an alternative methodology. The purpose was to explore the possibility of replacing today's cardboard based mock-up planning with models in a digital simulation environment.The purpose of the thesis has been to answer some of these complex questions; What are the benefits of using a simulation tool? In what way can we use it? If we choose to use a simulation tool, in what way does it affect our way of planning an assembly line? What are the advantages and disadvantages? Are there any economical and social aspects?Our results made us realize that a digital simulation tool does not replace the card board. On the other hand simulation could be used as a complement.

Utvärdering av laddningskoncept för lastbilsbatterier

When drivers overnight in the truck lots of electric energy is consumed by heaters, fans, lights and other extra equipment. If the engine is not running, this energy is taken from the lead/acid batteries of the truck which then needs to be recharged during operating hours. The fact that the charge acceptance of the lead/acid batteries is dependent on the temperature makes it hard to fully recharge the batteries at lower temperatures. A negative charge balance can lead to starting problems within a few days use in cold climate.In this thesis work, the effects of different battery charging concept are evaluated on the most common Scania battery (175Ah). A battery model is implemented in Matlab and some simulations of charging are made.

Funktionsupphandling av solelanläggningar

This thesis aims to contribute to improved functional procurement of photovoltaic systems, PV systems. Functional procurement means that criteria concerning a function are set rather than specifying technical details or products. Possible advantages and difficulties in using functional procurement have been analyzed by interviews, simulations and a case study. Electricity production and surplus production for different scenarios have been simulated via MATLAB. The MATLAB script was also used to generate rules of thumb on feasible solar fraction for six different load profiles; a church, a farm, a car mechanic, an office, an industry and an apartment building.

Utvärdering av datorprogram för användning vid dagvattenutredningar

The main object of this diploma work thesis is about how computer programs can bea tool to use for work on stormwater investigations. The advantage of using acomputer program compared with calculations made by hand is evaluated anddiscussed. The computer programs that have been used for studies and a sequence oftesting of the possibilities are Autodesks Storm and Sanitary Analysis and DHIs MikeUrban.Focus on sustainable development now permeates the building industry. As a resultstormwater investigations have been conducted in an increasing extent the recentyears. Stormwater is water produced due to precipitation, such as rain and snowmelt.Stormwater investigations normally contain descriptions of existing land use, plannedland use and suggestions of measures and technical solutions for the future disposal ofstormwater.The initial part of the thesis consisted of literature studies on stormwater andstormwater investigations to understand the science.

Klimatskärmens funktion : En jämförande analys av projekterade nybyggnationer i Östra Salabacke, ur ett energi- samt fuktperspektiv

The design of the building envelope affects the energy consumption of a building. As the energy requirements for new buildings are becoming more demanding, the performance of the building envelope must be improved. Energy efficiency and durability are important attributes to consider.This report includes investigations of the building envelope, moisture and passive solar energy. It is based on the analysis of two different buildings with different designs. These buildings stand as reference for two of the companies who are working on a new, climate smart, residential area in Uppsala, Sweden.Studies and analyses on energy consumption and moisture transportation were made.

Lagring av kyla med horisontella markvärmeväxlare för kylning av koncepthus i Mellanöstern

Norconsult AB has developed a solarhousing concept, a house designed for the warm climate in the Middle East andwith large quantities of solar panels installed. The cooling system for the house was designed in an earlier report, the purpose of this thesis is to investigate the possibility of short and long term storage of thermal energy via an underground energy storage volume.Two different designs of the storage and three different filling materials have been integrated into a model to simulate different cases. The first design consisted of pipes installed in the ground, without insulation. The second design consisted of an insulated concrete box installed to prevent thermal energy from the surrounding soil to flow towards the lower temperature regions within the storage. The three different filling materials were dry saudi sand, water saturated saudi sand and the filling material used by the client for energy storage in Sweden.The results from the simulations show that neither of the designs, regardless of the filling material, managed to extract enough thermal energy from the house to the ground to uphold the demands of indoor climate.

Energieffektivisering av modern tillbyggnad till äldre skola : fallstudie från Österbyskolan i Österbybruk

The Swedish government has introduced a goal to reduce the energy intensity by 20% to the year 2020. To reach this goal actions need to be taken throughout the energy sector which includes residential and commercial buildings. This thesis considers the possibility to reduce the energy usage in a building located close to Uppsala. The analyzed building is a combined office, cafeteria and entrance and was completed about half a year before this project started. Therefore the measures presented for a more energy efficient building are presented as measures for future constructions.Simulations have been made in VIP-Energy, a dynamic energy calculation program.

Självförsörjande elgenerering : Kan Orust bli självförsörjande på förnybar el?

Orust Kretsloppsakademi is a nonprofit organisation, with a goal of annually generate the same amount of electrical energy that is consumed. Orust is an island on the west coast of Sweden, north of Gothenburg. The population of 15 000 reaches 40 000 during summer, due to the large amount of vacationer. The total electricity demand is 174 GWh a year with a maximum power need of 32 MW. This report presents an analysis for the plausibility of their plan and from a power system stability perspective, the effects on the electrical grid.The conclusion is that the restraints for development of power generation from wind, solar and wave generation, are the power systems capability to transfer power, primarily in the transformers of the grid.

Drivaxeltrycksreglering hos tunga fordon : För en ökad framkomlighet vid vinterförhållanden

Heavy duty vehicles often have problems with traction during the winter periods. For vehicles that can lift tag axles it is possible to increase the normal force on the driven axle by lifting one or more tag axles, this will then increase the propulsive force of friction. This however increases wear on both road and vehicle. A possibility to reduce the wear while achieving nearly equivalent traction compared to lifted tag axles is to allow the vehicle to regulate the normal force by lowering the pressure in the air suspension associated with the tag axles or by the lifting of these axles. The vehicle would then by itself be able to set just the right amount of normal force on the drive wheels to avoid unnecessarily high normal forces while maintaining sufficient traction.The purpose of the report is to find out which parameters affect heavy duty vehicles when driving on slippery slopes and how traction can be improved.

Energieffektivisering av fastighet från 1930-talet : Utredning av energianvändningen och energieffektiviseringsåtgärder för Tången 2

Tången 2 is a building situated in Stockholm, Sweden. It´s built in the 1930s and contains both residences and businesses. The property owner, Diligentia AB, wants to lower the energy use in Tången 2. This report consists of an energy audit which clarifies the specific circumstances linked to Tången 2. Collected knowledge is then used, together with the results from the literature study, to decide energy measures to proceed with.

Att beskriva och jämföra en expertgrupp och intensivvårdssjuksköterskors överensstämmelse i att detektera delirium hos intuberade, respiratorbehandlade patienter med sedering/analgesi, före och efter en utbildningsintervention : En kvasiexperimentell stud

The aim: was to describe and compare a group of experts and critical care nurses' agreement in detecting delirium in intubated, ventilator treated patients with sedation / analgesia, before and after an in house training intervention with the instrument Confusion Assessment Method for the Intensive Care Unit (CAM-ICU).Method: A quasi-experimental study, one group pretest - posttest design. A convenience sample of 17 critical care nurses in a general intensive care unit included. To detect delirium the instrument CAM-ICU was used, 21 paired tests before and 22 after an educational intervention.Main Results: The results showed that after an in house training intervention sensitivity and kappa coefficient improved of the characteristic 1 "acute onset and fluctuating course," an improvement that was significant. In other features, and overall values were signs of numerical improvement and deterioration in sensitivity, specificity and kappa coefficient but no significant change.Conclusion: Implementing a new instrument for detecting delirium in clinical practice requires education and follow-up. A small sample of critical care nurses with varying ability to use the new instrument and the fact that patients' status may change rapidly making it difficult to draw any conclusions from this study.

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