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447 Uppsatser om Geography simulations - Sida 12 av 30

En studie av landskapsindex för kvantifiering av rumsliga landskapsmönster

Syftet med uppsatsen är att utvärdera två landskapsindex: ett formindex som beräknar formen för varje markanvändningsyta ( eng. "patch"); ett diversitetsindex, som beskriver de olika markanvändningarnas relativa utbredning. Formindexet beräknas på två olika sätt, beroende på om dess storleksberoende inkluderas eller ej. Utvärderingen körs för ett landskap på cirka 50 km2, men även för tre mindre områden i landskapet: åkerbygd, mellanbygd samt skogs-bygd. Samtliga områden jämförs sedan i två olika skalor, flygbild respektive satellitbild..

Aktivt system för tidvattenreglering av Lysekilsprojektets vågkraftsteknik

This report investigates a possible solution to the problem with adapting wave powerplants to work in countries with tidal water. The wire connecting the buoy at the surface with the generator at the bottom needs to adjust to the varying water depth. Our solution to this problem is to attach the wire to a jack which is then placed inside the buoy. The jack is then powered by an electric engine. The report discuss what forces the buoy will be exposed to and then the structural integrity of the design is evaluated through simulations.

Fem-studie av rörelser i planet mellan bakaxelbrygga ADA1100 och centralväxelhuslock R780

This thesis has been performed at Scania CV AB Technical Centre in Södertälje and its aim hasbeen to study the causes and effects of deformations in the interface between the rear axlehousing ADA1100 and the central gear house R780 during operation. Design changes that wouldincrease the sealing capability of the studied interface are also suggested. Finite element (FE)and CAD software have been the primary tools in this study.Finite element (FE) simulations are used in the industry to predict and develop engineeringdesigns. The main motive for FE simulations has traditionally been to identify weak spots in thedesign, regarding high tensions and large deformations.The FE model is an aggregation of submodels and interface models that represents the rear axlehousing, suspension, central gear, central gear housing, wheels, bolts and weldings, and theirinteractions. The submodels have different material properties and they are connected withcontact interface models.Boundary conditions are defined on the bushings in front of the rear axle and on the air bellowsbehind the rear axle.

Sårbarhetskartering av bekämpningsmedelsläckage till grundvattnet : tillämpat på vattenskyddsområdet Ignaberga-Hässleholm

Målsättningen med detta arbete är att ta fram en metod för att kartera och analysera den rumsliga variationen av landskapets sårbarhet för miljögifter, samt att visa hur geografiska informationssystem (GIS) kan underlätta denna rumsliga kartering och analys. Analysen utfördes inom vattenskyddsområdet Ignaberga-Hässleholm i Hässleholms kommun. Först studerades sårbarheten utifrån markens förutsättningar med hjälp av modellen DRASTIC och sedan studerades var de mest mobila bekämpningsmedlen har använts i förhållande till resultaten från DRASTIC..

Elever diskuterar geografi- Students discuss geography

Denna studie har som syfte att analysera de diskussioner som uppkommer kring en skönlitterär text som handlar om orkanen Katrinas framfart i New Orleans. Eleverna i undersökningen fick läsa en skönlitterär text och därefter ställdes en öppen fråga för att få igång gruppdiskussioner. Dessa diskussioner spelades in på band och analyserades. För att få en bild av elevernas uppfattningar om att lära genom en skönlitterär text, samt vad de ansåg om att diskutera texten tillsammans, gjordes intervjuer med fyra av eleverna. Resultaten visar att de flesta av eleverna utvecklades genom varandra i gruppdiskussionerna.

Markvattenhalt och temperatur i sandig jordbruksmark vid Ilstorp, centrala Skåne : en mätnings- och modelleringsstudie

Vinderosion på jordbruksmark har länge varit ett välkänt faktum trots att någon utförligare undersökning om dess omfattning och skadeverkan inte tidigare genomförts. Mot bakgrund av detta har därför ett nordeuropeiskt projekt, WEELS (Wind Erosion on European Light Soils), dragits i gång som syftar till kartlägga vinderosionen på sandig jordbruksmark i norra Europa och som man i slutändan hoppas ska kunna resultera i en vinderosionsmodell. Detta har genomförts med SOIL modellen, en matematiskt fysikaliskt baserad modell för simulering av vatten och värmeflöde i en skiktad jordmånsprofil..

Direct-EGR tillämpat på HCCI

The Homogeneous Charge Compression Ignition (HCCI) engine is promising in terms of lowNOx, low particulates and high efficiency. Due to its homogeneous charge, where thecombustion starts almost simultaneously from a number of points in the combustion chamber,only lean mixtures are possible to burn because of the resulting rapid combustion, which is muchfaster than the combustion in an SI-engine or a diesel engine. When richer mixtures are used thecombustion will start earlier and also be more violent.To phase the combustion later and lower the combustion speed, external cooled EGR can beused. The EGR-system used in this thesis uses a divided exhaust channel where one channel andits corresponding valve are used only for transporting EGR back to the intake system.Consequently the EGR-valve is connected to the intake pressure. This system is called Direct-EGR (D-EGR).Engine tests verified that the CA50 indeed is phased later when cooled EGR is used.

Kväveläckage inom Tolångaåns dräneringsområde : modellering och åtgärdssimulering

Under de senaste 300 åren har jordbrukslandskapet i Sverige genomgått stora förändringar. I början av 1900-talet introducerades konstgödslet och efter andra världskriget ökade gödslingen dramatiskt i syfte att maximera produktionen. Detta har lett till att överskottet av kväve har spolats ut i vattendragen. I detta arbete har stor vikt lagts vid att skapa en egen kvävemodell i syfte att simulera kväveläckaget från jordbruksmarken i Tolångaåns dräneringsområde..

Evenemang : -ett vinnande koncept för regional utveckling?

Event is a phenomenon that lately has become more common, especially within the tourism industry. This essay is a study within human geography and with focus on the meaning and the design of events. The purpose with this essay is to examine and describe the concept of event and to show how events can influence a region. Falkenberg is situated in the county of Halland by the west coast and the sea and because of that a natural tourist destination. The city is a known seaside resort since the end of the nineteenth century.

Hopfällbar hjullösning

In many products a compromise between ground clearance and the required space to store the product has to be made. This problem attracted the attention of the authors of this thesis.The objective of this project is to develop a functioning solution to a foldable wheel. The solution should be applicable to several types of product groups. A limitation for this work has been made so that the work only covers solutions for lighter vehicles.The purpose is to drive this project forward, so that a solution can be found. Furthermore the purpose of the report is to clarify how the authors proceeded to design and construct the wheel according to a fixed specification.

Modell och analysverktyg för beräkningav frekvensförlopp

The power system modelled in this thesis work has been developed for simulationwhen e.g. the production in some part of the power system is changed. The powersystem has been modelled according to the swing mass of the system, the frequencydependency of the load and the turbine governor. The model determines the systemfrequency, the period of regulation and the power exchange between the differentsubsystems in the Nordic synchronized system.In this model the system frequency is assumed to be the same in all different parts ofthe power system and the voltage conditions in the power system are neglected. Forthat reason power swings does not occur between different subsystems in the powersystem, which usually occur as a result of the swinging connection between thetransmissions line.

Bestämning av optimal fordonspark -Distribution av bitumen vid Nynäs AB

Nynas produces bitumen at two refineries in Sweden. The bitumen is shipped to seven depots along the swedish coast line, and from the depots special trucks handle the transportation to customers. Recently Nynas has transformed its supply chain and closed down a few depots. At the moment the company is considering a further reduction of the number of depots. In connection to these discussions an analyse of the companys distributionsystem and of possible changes is required.

Konstruktion av statorstomme för synkrongenerator : Förslag på design av statorstomme för användning i vertikalaxlade vindkraftverk

This thesis describes a conceptual design of a support frame for a synchronousgenerator used in a vertical axis wind power plant. In this system the generator isplaced on ground level. The thesis also considers the design of housing for thesupport frame and generator. The concept presented in this report is based on anearlier design. Besides geometric design, simplified simulations has been run in orderto optimize some of the parts included in the construction considering naturalfrequencies and structural strength.The result is presented as CAD-models andan assembly drawing..

CFD simulering av en fyrtakts Otto motorcykel motor

This thesis deals with the numerical 3D simulation of a four stroke, spark-ignited, internalcombustion engine, which is mounted on a high performance motorcycle. The work, carried outin collaboration with Politecnico di Milano and MV Agusta, focuses on the simulation of theintake, compression and expansion stroke, including combustion simulation, using an opensource CFD code.Simulation of internal combustion engines offers a great challenge in the field of CFD research.Moving boundaries of the solution domain, caused by the motion of the piston and valves, leadsto deformation of the computational grid, with decreasing quality of the solution as result. Basedon this, a previously developed mesh motion strategy was employed where a number of meshesare used to cover the whole simulation cycle. Within each mesh interval the internal cell pointsof the mesh are moved to account for the boundary motion of the piston and valves. This strategywas previously applied to simplified geometries as well as real engine geometries.

Analys av spänningsstabilitetsberäkningar i det svenska elsystemet

Numerical simulations play a vital role in both static and dynamic stability assessment of electric power systems and the foreseeing of voltage collapse. Simulations performed by Svenska Kraftnät(SvK) are mainly done in the specialized voltage collapse predicting software tool, SPICA and the more all?purpose software tool, ARISTO.The grid operators at SvK use SPICA to predict the maximum transfer limit at specified sections (in this report the section in concerns is the southern part of Sweden i.e. interface1 4). SPICA is mainly used as an online application by using actual states from the grid, these states update every quarter of an hour.This thesis is a continuation of the master thesis SPICA ? ARISTO JÄMFÖRELSE by Jakob Katzman and Johan Fält.

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