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267 Uppsatser om Layer thickness - Sida 1 av 18

Strömningen i och över en skog : utvärdering av en 'mixing-layer' hypotes

A new theory for predicting the windprofile over a canopy has been evaluated. The theory was first presented by Harman and Finnigan (2007). The theory relies on the forming of a mixing-layer above the canopy, due to different mean wind in and above the canopy. Characteristics from both mixing-layer and Monin Obukhov similarity theory have been used to develop the governingequations that give the wind profile. The theory has been used to calculate wind profiles for sixdifferent atmospheric stabilities.

CFD-simulering av kallras från fönster : Konvektorers och nischdjupets inverkan på lufthastigheter i rummet

During cold winter days it is likely that people in buildings with older windows or high glass facades experience thermal discomfort due to cold air down draughts. Earlier work has been aimed at finding analytical methods to predict the speed of the airflow in a room and in practice heating appliances are often placed beneath the windows to reduce the draught along the floor. In a study from 2012 Mohammad Parchami developed a method for estimating the required heating power to counteract the downdraught with such heating appliances. In this study, Computational Fluid Dynamics (CFD) was used to evaluate the usefulness of Parchami?s method and also to examine the potential of adapting the depth of the inward window sill as a means of decreasing the down draught.

Är variation i STFI-tjocklek ett bra mått på kartongs bulighet? : Are variation in STFI-thickness a good measure of uneven surface, bumpiness, on cardboard?

This degree project aim to evaluate if variations of the STFI thickness can be used to assess bumpiness on cardboard. During the project cardboard samples were measured using Bendtsen, PPS, a L&W formation tester, OptiTopo, Ambertec formation, the STFI thickness tester and a visual comparison. The different methods were then compared to see if there is any correlations between them. The results showed that the visual comparison and OptiTopo correlates. The STFI thickness tester shows however no correlation with the OptiTopo and visual comparison, thus aren't suitable measuring bumpiness..

Betydelsen av hästens hud och päls för reglering av kroppstemperatur i kyla ? vad händer vid klippning och täckning?

The horse is a homeothermic animal and to keep a constant body temperature in winter season is important. Acclimatisation is to provide means for a good thermal insulation consisting of skin, hair, and an outer air layer. The skin covers the horses body and it is composed of three main layers where the top layer of the epidermis consists of dead keratinized cells that are constantly being sheed. The dermis is composed of collagen connective tissue that give the skin its strength. The bottom layer with subcutaneous fat provides a thermal insulation and can be used as an energy reserve in cold weather.

A Cross-Country Skiwear Collection for Beautiful Women

This thesis deals with cross-country ski clothing for non-competitive women. Women in this category look for different clothing features in comfort and aesthetics than male top athletes, for whom cross-country skiwear today often seems to be designed. In this thesis the demands of these women have been mapped out by an interview with a reference group of users. The ergonomics of exercising in the winter outdoors are naturally a base for the collection. The collection consists of three functional layers of garments.

Oljefilmens tjocklek mellan kolvring och cylinderlopp

Hägglunds Drives in Mellansel, Sweden, manufacture radial piston hydraulic motors foremostwithin applications in the industry. These motors have several sliding contacts, one of these, isthe contact between piston ring and cylinder bore. The radial piston hydraulic motors advantageis to produce high torque in very low rotation velocity, this result in that the maximum slidingvelocity between piston ring and cylinder bore, during the whole stroke, is very low. Theconsequence of this low sliding velocity is that the contact between piston ring and cylinderbore, during the whole stroke, is bound to the boundary lubrication regime. This result in, thatthe piston ring is exposed to wear, thus affect the service life of the complete hydraulic motor.To minimize wear of piston ring, it is essential to determine the oil film thickness between thepiston ring and cylinder bore.

Modellering och simulering av hydraulik för användning i hardware-in-the-loop

Modeling and simulation is growing ever more important in the development of new products. This thesis describes the use of Hopsan for hydraulic modeling and its use in conjunction with Simulink with the intent of using the model in a hardware-in-the-loop setup. A sensor layer has been created in Simulink to emulate all the internal sensors in a modern forklift. The details of using legacy C-code instead of a hardware MCU for a fully simulated environment, software-in-the-loop has been outlined. There are two major routes one can follow implementing software-in-the-loop, exporting the C-functions to CAPL via a export layer or creating an s-function in Simulink.

Hårdgörning av Asp

Hårdgörning av trä syftar till att göra materialet hårdare. Detta går att åstadkomma genom komprimering, det komprimerade materialet tenderar dock att återgå mot sin ursprungsform då materialet utsätts för fukt om ingen låsning sker. Låsningen kan ske mekaniskt i en treskiktskonstruktion som motverkar träets fuktrörelser. Dessa skivor har dock visat sig vara instabila och tidigare försök har uppvisat deformationer i form av kupning. Denna undersökning syftar till att utreda förutsättningarna för att använda komprimerad asp samt att ta fram underlag för framtagning av en kommersiell produkt.Praktiska tester har genomförts för att studera hårdhet, återfjädring och densitet hos det komprimerade virket.

Konstruktion av värmespridare med grafit för flygelektronik

This master thesis was carried out for Saab Avitronics, a business unit of Saab ABactive in electronic systems for military aircrafts. Reliability and weight are of crucialimportance in this environment. To improve reliability and lower the weight graphitemay be used for electronics cooling. Graphite is an anisotropic material and hasthereof high thermal conductivity in two directions (in-plane) and a relatively lowconductivity in the third direction (through thickness).The purpose of this thesis was to investigate if graphite is an adequate thermalconductor to use in PCB carriers. The carriers support and cool the PCB by divertingthe heat dissipation from the PCB components to the edge.

UV-tork - analys av drift :  

The company Somas, Säffle, has assigned Fredrik Kjellin the project of finding out how ?KVTF DN250?, one of their own valves, reacts on cutting forces under production. They wish to know if and then how much it?s possible to minimize the wall thickness of the valve with neither plastic nor to big elastic deformations caused by processing.The most critical processes have been identified as rough lathing. The study has shown that the marginal for a wall thickness of two millimeters, to fall short of the yield stress in the most critical process, is good.

Characteristics of Swedish gilts at service and producers? opinions about gilt production

In Sweden, selection for leanness in pigs has been going on for almost a century. This sometimes results in gilts and sows being too lean and consequently in a risk for reduced reproduction and health status. The Swedish recommendation includes that gilts should be mated after seven months of age, after one documented oestrus, at 120-140kg live weight and with a backfat thickness of 16-20mm. Five gilt producing herds were visited and records of age, heart girth (for weight estimation), body condition (visual estimation), backfat thickness and exterior were made. The same records were also taken in four gilt buying herds on newly purchased gilts.

Dimensionering av ventilhus med avseende på skärkrafter

The company Somas, Säffle, has assigned Fredrik Kjellin the project of finding out how ?KVTF DN250?, one of their own valves, reacts on cutting forces under production. They wish to know if and then how much it?s possible to minimize the wall thickness of the valve with neither plastic nor to big elastic deformations caused by processing.The most critical processes have been identified as rough lathing. The study has shown that the marginal for a wall thickness of two millimeters, to fall short of the yield stress in the most critical process, is good.

Samband mellan tjockleken hos PVD-skikt och förslitningsbeteendet vid svarvning

This project has as main goal to study the influence of the coating thickness, deposited by arc-PVD- technology, on the wear resistance of coated cemented carbide inserts in three different turning operations. An additional effort has also been made to develop a new test method for evaluating flank wear resistance. Three different coating types (Coating A, Coating B and Coating C) have been studied in three distinctive thicknesses (2, 4 and 6 µm) for each type. For two of the coating types (Coating A and B) special studies has been done with the thickest coating, creating two additional coating versions of the thickest coating, by changing various deposition parameters, with the aim to enhance the cohesive properties of the coating and lower the residual stresses at the cutting edge. The results show increased crater wear resistance with increased coating thickness for all coating types, but the amount of increase changes with coating type (Coating A>B>C).

Simulering av valkar i pappersrullar : och analys av de slappa stråk som uppkommer

A baggy paper web has parts that are longer than neighboring parts. One of the assumed reasons for bagginess is thickness variations of the paper. In the roll the thicker streaks then add up to form a ridge. In the ridges the paper is strained and during storage the strain may become permanent. When the paper unreeled it is then baggy.

Nedfästning av oljemåleri på puts.En fallstudie från salongen på Mostorps slott i Halland

This thesis, designed as a case study, is about complications concerning conservation of a decorative oil paint on lime plaster from the drawing-room in Mostorp castle sited in the county of Halland in south-west of Sweden. The building was built 1878-80 with an exterior of granite. The interior walls were made of clay bricks, lime mortar and lime plaster. The oil paint is applied to a layer of putty. The combination of different materials, which are organic and inorganic, affects the movement caused by internal and external stress.

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