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2955 Uppsatser om Control valves - Sida 2 av 197

En frivillig standards kvalitetsma?ssiga pa?verkan pa? redovisning av varuma?rken : ISO 10668

Title: Co-operative, prevent or complement? - An essay on the relationships between control systems. Authors: Kim Eriksson and Victoria KarlssonPurpose: The essay aims to describe the relations between control systems and how they related to each other, based on an operationalization of the control systems. Research question: What are the control systems relations to each other? With regards whether control systems co-operative, prevents and/or complement each other.Theoretical framework: The essays theoretical framework is based on Malmi and Browns (2008) description of five different control systems and control mechanisms associated with each control system.   Research methodology: The method was based on three different data collection methods. These methods were observations, documentation, and semi-structured interviews.Conclusions: It is concluded that the control systems has comprehensive relations. Control systems have more, than one, relation to each other..

En studie om artikelhantering i material- och produktionsstyrningssystem på System Andersson AB

This thesis aims to develop a control system for measuring electromagnetic compability (EMC). This has meant that a controller designed around an ATmega8 microcontroller has been manufactured and programmed. It has also meant the development of a comprehensive control software in the program MATLAB. The control system has been tested with satisfactory results and can now, monitor and control measurements of the EMC-type..

Energioptimering : Resteffektkylning av mellanlager för använt kärnbränsle (CLAB) Oskarshamn

This thesis is done in cooperation with SWECO Energuide in Växjö. They have been assigned by SKB in Oskarshamn to renew their electrical power supply and the ancillary processing systems in their Central provisional storage of spent nuclear fuel, CLAB. Today in the CLAB facility, the spent fuel is cooled down with water pumps, driven by asynchronous induction motors, where the water is regulated by mechanical valves to the desired flow. After the upgrade, the engines will be powered by AC drives that can control the pumps by changing the rotational speed and thus change the water's cooling effect on the nuclear fuel. In this study, I investigated the interference AC drives causes the feeding network and how to go about averting them.

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.

Adaptiv temperaturreglering av bostadshus

The control of indoor temperature must be able to handle large time constants and both measureable disturbances like outdoor temperature, and non-measurable disturbances, like waste heat from appliances. Due to cheaper microcontrollers (small computers with designated tasks) with better performance, more advanced and computation-demanding methods for control can be used.In this thesis, Generalized Predictive Control (GPC) has been implemented and tested on a theoretically derived model of a house. GPC states that a model of the system is estimated in every sample, and the control is carried out simultaneously, based on predictions of the model. Disturbances like solar radiation can be estimated and used in the control as well. The control signals are determined by quadratic programming, which makes it possible to consider conditions, for example limitations on the control signals.GPC requires a number of parameters to be defined, like model order and control signal penalty, but is relatively robust for variations in them.

Aortainsufficiens hos häst : patofysiologi och behandling

Aortic insufficiency is a very common valve problem in horses and most often affects older individuals, but nevertheless existent within younger ones. The root cause for aortic insufficiency can be varied, for example; endocarditis, ventricular septum defect or congenital valve disease but the most common are progressive valve degeneration or elite competition. Depending on the root cause, different changes can be observed on the aorta valves, but they do all have the same effect, the valves do not seal properly and blood leaks backwards. Many horses can, even with this deficiency, perform highly without any visible impacts and there is therefore no need to treat those subjects. Most often the symptoms arise at a later stage in life and they are, more often than none, put down for other reasons. In the occurrence of the clinical symptoms showing, treatment guideline is to inhibit these symptoms since the valve degeneration is presently irreversible.

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.

Traditionell ekonomistyrning vs modern verksamhetsstyrning - en fallstudie av ett växande företagsstyrfilosofi

The purpose with this paper is that trough a description of the management control at Jitech AB find out if traditional management control have been abandoned for benefit for modern management control and in which extent the transition have happened. Further is the second purpose with this paper to find out which decisions that lies behind the design of the management control and how these are in opposition to with the theory..

Missilstyrning med Model Predictive Control

This thesis has been conducted at Saab Bofors Dynamics AB. The purpose was to investigate if a non-linear missile model could be stabilized when the optimal control signal is computed considering constraints on the control input. This is particularly interesting because the missile is controlled with rudders that have physical bounds. This strategy is called Model Predictive Control. Simulations are conducted to compare this strategy with others; firstly simulations with step responses and secondly simulations when the missile is supposed to hit a moving target.

EKONOMISTYRNING AV BUTIKSVERKSAMHET: ? en fallstudie av modeföretaget ?Alfa?

The aim of this thesis is to examine how salesperson control can be exercised in a retail store environment. A case study has been performed on a Swedish fashion company emphasizing the relationship between the company?s upper level management and their retail store operations in order to describe, analyze and classify the prevailing management control mechanisms. The paper presents an agency theoretical approach to the relationship applying behavior- and outcome based control theory, performance measurement theory and incentives theory in order to give a comprehensive image of the control system. The main finding is that the company?s management control system as applied to the sales force in its retail stores can be categorized as mainly behavior-based despite several explicit outcome-based features..

Pneumatiska artificiella muskler : med hjälp av en robotarm

According to the study [1] several firefighters are killed in action each year. This happens naturally in various ways. One of the major factors is that firefighters often do not know how the environment looks like, for example that a building in an industrial area contains hazardous gas cylinders. Without a solution, fire-fighters will continue to die in duty. It is therefore important to solve this problem so that we can minimize the risks and save lives.The goal of this project was a control system for pneumatic artificial muscles.

When companies grow up - A case study of a family-owned company?s management control system

Problem: What are the characteristics of Polykemi?s management control system and how is it affected by growth? Purpose: To describe and analyse the management control system of a medium-sized family-owned company from the perspective of Simons? Levers of control. Research design: An abductive, interview-based case study of Polykemi AB. Conclusion: Polykemi?s management control system is primarily a traditional one which is rather strong in terms of Levers of control.

Analys och modellering av ljusbåglängdsregleringen i pulsad MIG/MAG-svetsning

This master thesis deals with problems in the arc length control in Pulsed MIG/MAG Welding. The main problem is that it is not possible to measure the arc length. In the present solution the voltage over both the electrode and the arc represents the arc length. To improve the arc length control a model of the electrode melting has been built. One output from the model is the voltage over the electrode and with this voltage together with the measured voltage it is possible to calculate the voltage over just the arc.

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.

Verksamhetsstyrningens inverkan på målprioritering - En kvalitativ fallstudie av två vårdcentraler i Stockholms läns landsting.

This study aims to examine the effect management control systems have on which goals health centers prioritize. The management control systems of one privately owned and one publicly owned health center have been studied through a qualitative case study. Robert Simons (1995) framework with four levers of control (diagnostic control systems, interactive control systems, belief systems and boundary systems) has been used to structure the study. For both health centers we found a conflict of interest mainly between the diagnostic control system and the beliefs system, where the diagnostic control system is biased towards quantitative goals and the beliefs system is mainly biased towards qualitative goals. However, despite the unbalanced levers of control the studied health centers have been able to reach a well functioning compromise between quantitative and qualitative goals..

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