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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Marknadsföring i skråväsendets skugga : En undersökning av möbelannonser i Stockholms Dagblad 1840–1870

Larsson, Per January 2016 (has links)
Eftersom man från tidigare forskning, gjord av bland andra Erik Lindberg, Sofia Murhem och Göran Ulväng, kan se att det fanns en konflikt mellan ett ökande behov av att marknadsföra möbler och skråväsendets reglering av annonseringen så undersöks i denna uppsats hur annon-seringen förändrades i och med skråväsendets avskaffande 1846.Undersökningen inriktar sig på Stockholm under perioden 1840–1870 och använder Stock-holms Dagblad som huvudsaklig källa. Genom att jämföra annonserna för den del av möbel-försäljningen som berördes av annonsregleringen med den icke reglerade annonseringen för begagnade möbler samt utvalda annonser för andra typer av varor så kartläggs eventuella för-ändringar. Annonserna jämförs för månaderna april och oktober under 1840, 1855 och 1870.Undersökningen visar att det skedde en utveckling under perioden och att möbelannonserna 1870 var lättare att upptäcka i mängden, med tydligare rubriker och mer marknadsinriktade budskap. Utvecklingen gick dock långsamt och det skedde en tydlig tillbakagång 1855 då så gott som inga annonser för nytillverkade möbler förekom.Den annonsreglering som fanns under skråtiden tycks därmed ha fortsatt påverka marknads-föringen även efter att skråna hade avskaffats.
12

Förstudue till en Miljökonsekvensbeskrivning angående rivning av vattenkraftesdammar : Samt simulering av av vattenflöden / Pre-study for an Environmental Impact Assessment regarding demolition of hydroelectric ponds : As well as simulation of water flows

Viklöf, Evelina January 2019 (has links)
On the basis of a legislative amendment that came into force in January 2019, which states that all dams will have to achieve modern environmental conditions, all hydropower dams in  Sweden will need to be licensed. Arvika Kraft has two regulating dams Kivilamp and Rolamp  which they do not believe will achieve the modern environmental conditions. Arvika Kraft  therefore wants to have a feasibility study for an environmental impact assessment carried out  in order to be able to study possible measures for the dams. They wanted a potential  demolition of the two regulatory ponds to be studied in this preliminary study. In an environmental impact statement, several alternatives are to be studied, and in this  feasibility study, the zero alternative is to maintain the regulating dams as they are today, the  main alternative being to demolish the two damsand the third alternative that was chosen to be  studied is the introduction of turbines in the dams along with the construction of fish roads  passing them.  In the report, a literature study is carried out to deepen the knowledge in the area, a modeling of the three alternatives to be able to study how the energy production of the power dam  downstream as Kivilamp and Rolamp acts as a regulator are affected, and finally the actual  collection of information for the preliminary study of the environmental impact assessment.  The result of the study shows that the zero alternatives contribute to regulation that increases energy production of the power dam downstream but that the two ponds Kivilamp and  Rolamp are migratory obstacles to the aquatic animals. The problem with the zero alternative  also remains that there is a great risk that the dams do not meet the modern environmental  goals at present.  The result of the main alternative shows that, according to the models, energy production would be lowered in the event of a demolition of the two regulating dams. The water flow, on  the other hand, would be more natural and the two migratory obstacles would disappear for  the aquatic animals. However, the flow would continue to be dammed downstream, which  would mean that only a small section of the total flow path would be free from migratory  obstacles.  For the third option studied, the result was an increased energy production but not as high as expected because the two regulating dams had a relatively low drop height compared to the  power dam downstream and that the flow was somewhat lower for Kivilamp and Rolamp in  comparison. By way of the constructed fishing roads, on the other hand, free movement would be facilitated and this would be a positive change for the aquatic animals.  The conclusion was that the best alternative where energy production was weighed together with an improved environment for the aquatic animals was the third option. However, this can  be costly and difficult to implement in practice and in such cases the best thing would be to  demolish the regulating dams.
13

Analys av värmesystem Effektreducering / Analysis of heating system Reduction of power

Westerstedt, Jerry January 2010 (has links)
Innehållet speglar både kostnadseffektiv ingenjörskonst och driftstrategiska investeringar dels i form av analyser av nuvarande och kommande effektkonsumtion samt effektbehov, dels idéer på hur vidsträckta problem kan lösas med relativt enkla tekniska konstruktioner.Analyserna omfattar undersökning av potentiella värmekällor vilket resulterat i konkreta förslag på vilka som kan vara aktuella samt vilka som ej kommer att hålla rätt kvalité. Undersökningen innefattar även beskrivning av rådande förutsättningar för rekommenderad värmekälla samt hur en eventuell projektering bör formas med avseende på vilka materiella val samt variabler som bör beaktas vid installation.Framförallt hur stor den primära effektreduceringen blir genom att följa de åtgärder som rekommenderas i rapporten, dels analyseras det befintliga värmesystemets olika delar genom en momentan jämförelse som ger en bild av delsystemens inbördes betydelse beroende på vad de faktiskt bidrar med effektmässigt. Rapporten innefattar även en undersökning av det befintliga värmesystemets komponenter och rekommenderar vilka komponenter som bör åtgärdas omgående samt varför och hur det bör ske. Innehållet som helhet belyser betänkliga råd som bör beaktas inom en snar framtid, rapporten framhäver stora som små investeringar med avseende på att öka driftsäkerheten samt att på sikt generera en större reducering av nuvarande driftkostnad. Det återfinns ett förslag på en intelligent styrning som till viss del kan ersätta de fördelar som en manuell styrning faktiskt medför i form av de sinnen och egenskaper som den mänskliga faktorn bidrar med såsom syn, känsel och erfarenhet.
14

Reglering av klinkerugn för framställning av zinkklinker / Kiln control for processing of zinc clinker

Bergmark, Anders January 2005 (has links)
<p>I fumingverket på Rönnskärsverken utvinns zinkklinker ur slaggen från elugnen. En annan råvara är stålverksstoft. I fumingugnen omvandlas smältans zink- och blyinnehåll till metallånga som oxideras till ett stoft. Stoftet renas i en klinkerugn. Slutprodukten, zinkklinker, som består av 70 - 75 % zink, exporteras till zinksmältverket Norzink i Norge. Klinkerugnen är ett väldigt långsamt system med stegsvarstider i storleksordningen en timme vilket gör den svårstyrd och det resulterar i störningar och stilleståndstid med låg produktion och låg kvalitet på klinkern. För att lösa detta problem testas automatisk reglering i detta arbete. Två processmodeller tas fram för simulering och reglerdesign och tre regulatorer har utvecklats i simulering. Två av dessa testas på den faktiska processen. Vidare har ett ramverk för snabb utveckling och testning av regulatorer utvecklats. En C++-klass för kommunikation via DDE-gränssnittet mellan regulator och operatörsgränssnittet har också konstruerats.</p> / <p>In the fuming plant at Rönnskärsverken smelter, zinc clinker is xtracted from slags and steel mill dust. In the fuming furnace, zinc and lead are vapourised by coal injection. The reoxidised metal dust is further refined at the clinker plant to obtain a product that is low in halogenes. Zinc clinker, which contains approximately 70 - 75 % zinc, is exported to the Norzink zinc smelter in Norway. The refinement takes place in an industrial kiln. The kiln is a very slow system and therefore difficult to control which results in disturbances and dead time. This causes low production rate and poor quality in the clinker. In order to cope with this, automatic control is tested in this thesis. Two process models have been built for simulation and control design and three controllers have been evaluated in simulation. Two of the developed controllers are tested on the actual process. A framework for fast controller prototyping has also been developed. A C++-class för communication using the DDE interface between controller and the operator user interface has also been implemented.</p>
15

Styrlagsdesign för ett instabilt stridsflygplan med hjälp av QFT

Dahlgren, Joacim, Gustafsson, Daniel January 2005 (has links)
<p>A modern fighter aircraft is exposed to very different flight conditions and must despite that perform infallibly in every single situation. Several variables like center of gravity, speed, altitude and weight vary during a standard mission flight or</p><p>between flights. For the aircraft to be able to perform effectively, superior manoeuvrability is vital. Hence it is of great importance that the flight control system is capable to cope with these different variations.</p><p>In the 1960s professor Isaac Horowitz presented the method Quantitative feedback theory (QFT) which is a method whose aim is to manage system variations. The method can be useful in the construction of the control system for a fighter aircraft. QFT is a frequency based method whose main objective is to shape the</p><p>open loop gain in a Nicholschart to meet the required closed loop demands. A prefilter is then applied to achieve correct reference tracking.</p><p>This thesis is divided into two parts, where the first part presents the method QFT for both the SISO-systems and for the MIMO-systems. For the MIMOsystems several design techniques are presented, the chapter also includes a method on the implementation of state feedback. Furthermore statements of how nonlinear and unstable systems are handled with the QFT is included.</p><p>The second part of the thesis presents the design of a control system for an unstable fighter aircraft. The design is constructed for the SISO longitudinal dynamics as well as for the MIMO lateral dynamics, where the design must be robust against variations in speed, altitude and center of gravity.</p><p>The flight control system that is implemented meets almost all requirements and gives good preformance and this is achieved with only a few regulators. Proposals of possible solutions to those requirements note yet reached are discusssed.</p>
16

Modellbaserad prediktiv reglering av en dieselmotor med variabel geometriturbin och återcirkulering av avgaser / Model Predictive Control of a Diesel Engine with Variable Geometry Turbine and Exhaust Gas Recirculation

Wahlström, Johan January 2003 (has links)
Control of a diesel engine equipped with Variable Geometry Turbine (VGT) and Exhaust Gas Recirculation (EGR) requires a multivariable control method. One problem is that the engine system is non-linear. Furthermore there are strong cross-connections between inputs and outputs and the inputs have alsoboundaries. To be able to manage these control problems, MPC has been used that is a multivariable method. The MPC-controller consists of an optimization problem and therefore MPC can find the optimum control signals in an easy way. Furthermore the boundaries of the control signals can be handled with by-conditions in the optimization. The disadvantage with MPC is that it requires a lot of amount of calculations and memory, which are important factors when a control system should be implemented. Therefore it has been chosen to compare MPC with PID, that is a common and simpler method. The results from this thesis are that MPC is a method that gives more optimal and faster control. Furthermore MPC can handle different control cases much better, without changing the settings. On the other hand PID requires considerable fewer amounts of calculations and memory. In one case that has been examined, MPC requires 40 times more amounts of calculations than PID. To be able to control a non-linear system, both MPC and PID must be implemented in several different working points. Furthermore decoupling must be used in the PID-controller to be able to manage cross-connections that seems to be a very important problem.
17

Reglering av klinkerugn för framställning av zinkklinker / Kiln control for processing of zinc clinker

Bergmark, Anders January 2005 (has links)
I fumingverket på Rönnskärsverken utvinns zinkklinker ur slaggen från elugnen. En annan råvara är stålverksstoft. I fumingugnen omvandlas smältans zink- och blyinnehåll till metallånga som oxideras till ett stoft. Stoftet renas i en klinkerugn. Slutprodukten, zinkklinker, som består av 70 - 75 % zink, exporteras till zinksmältverket Norzink i Norge. Klinkerugnen är ett väldigt långsamt system med stegsvarstider i storleksordningen en timme vilket gör den svårstyrd och det resulterar i störningar och stilleståndstid med låg produktion och låg kvalitet på klinkern. För att lösa detta problem testas automatisk reglering i detta arbete. Två processmodeller tas fram för simulering och reglerdesign och tre regulatorer har utvecklats i simulering. Två av dessa testas på den faktiska processen. Vidare har ett ramverk för snabb utveckling och testning av regulatorer utvecklats. En C++-klass för kommunikation via DDE-gränssnittet mellan regulator och operatörsgränssnittet har också konstruerats. / In the fuming plant at Rönnskärsverken smelter, zinc clinker is xtracted from slags and steel mill dust. In the fuming furnace, zinc and lead are vapourised by coal injection. The reoxidised metal dust is further refined at the clinker plant to obtain a product that is low in halogenes. Zinc clinker, which contains approximately 70 - 75 % zinc, is exported to the Norzink zinc smelter in Norway. The refinement takes place in an industrial kiln. The kiln is a very slow system and therefore difficult to control which results in disturbances and dead time. This causes low production rate and poor quality in the clinker. In order to cope with this, automatic control is tested in this thesis. Two process models have been built for simulation and control design and three controllers have been evaluated in simulation. Two of the developed controllers are tested on the actual process. A framework for fast controller prototyping has also been developed. A C++-class för communication using the DDE interface between controller and the operator user interface has also been implemented.
18

Styrlagsdesign för ett instabilt stridsflygplan med hjälp av QFT

Dahlgren, Joacim, Gustafsson, Daniel January 2005 (has links)
A modern fighter aircraft is exposed to very different flight conditions and must despite that perform infallibly in every single situation. Several variables like center of gravity, speed, altitude and weight vary during a standard mission flight or between flights. For the aircraft to be able to perform effectively, superior manoeuvrability is vital. Hence it is of great importance that the flight control system is capable to cope with these different variations. In the 1960s professor Isaac Horowitz presented the method Quantitative feedback theory (QFT) which is a method whose aim is to manage system variations. The method can be useful in the construction of the control system for a fighter aircraft. QFT is a frequency based method whose main objective is to shape the open loop gain in a Nicholschart to meet the required closed loop demands. A prefilter is then applied to achieve correct reference tracking. This thesis is divided into two parts, where the first part presents the method QFT for both the SISO-systems and for the MIMO-systems. For the MIMOsystems several design techniques are presented, the chapter also includes a method on the implementation of state feedback. Furthermore statements of how nonlinear and unstable systems are handled with the QFT is included. The second part of the thesis presents the design of a control system for an unstable fighter aircraft. The design is constructed for the SISO longitudinal dynamics as well as for the MIMO lateral dynamics, where the design must be robust against variations in speed, altitude and center of gravity. The flight control system that is implemented meets almost all requirements and gives good preformance and this is achieved with only a few regulators. Proposals of possible solutions to those requirements note yet reached are discusssed.
19

Motivation på arbetsplatsen : Self-Determination Theory i en organisatorisk kontext

Bergqvist, Sofie, Edin, Michaela January 2012 (has links)
Syftet med studien är att undersöka huruvida Self-Determination Theory kan appliceras som förklaringsmodell för motivationen hos de anställda på Företaget X. Enligt Self-Determination Theory råder ett samband mellan tillfredsställelsen av basbehoven; autonomi, kompetens och släktskap i arbetsmiljön och motivationstypen hos individen. Tillfredsställelse av basbehoven främjar autonom motivation framför kontrollerad motivation och genererar antingen internalisering av yttre motivation och/eller bibehållande av den inre motivationen. För att undersöka sambandet mellan variablerna genomfördes en enkätundersökning med både anställda i ledande och icke-ledande position. Enkätens resultat visar att basbehoven är tillfredsställda och att motivationstypen är av karaktären inre motivation respektive hög grad av internaliserad motivation. Däremot kan studien inte fastslå ett statistiskt säkerställt samband mellan dessa variabler och kan därför inte bekräfta att Self-Determination Theory fungerar som förklaringsmodell för motivationen hos de anställda på Företaget X. Författarna anser dock att resultaten indikerar på samband i den utsträckningen att de inte vill förkasta teorin.
20

Modellbaserad prediktiv reglering av en dieselmotor med variabel geometriturbin och återcirkulering av avgaser / Model Predictive Control of a Diesel Engine with Variable Geometry Turbine and Exhaust Gas Recirculation

Wahlström, Johan January 2003 (has links)
<p>Control of a diesel engine equipped with Variable Geometry Turbine (VGT) and Exhaust Gas Recirculation (EGR) requires a multivariable control method. One problem is that the engine system is non-linear. Furthermore there are strong cross-connections between inputs and outputs and the inputs have alsoboundaries. To be able to manage these control problems, MPC has been used that is a multivariable method. The MPC-controller consists of an optimization problem and therefore MPC can find the optimum control signals in an easy way. Furthermore the boundaries of the control signals can be handled with by-conditions in the optimization. The disadvantage with MPC is that it requires a lot of amount of calculations and memory, which are important factors when a control system should be implemented. Therefore it has been chosen to compare MPC with PID, that is a common and simpler method. </p><p>The results from this thesis are that MPC is a method that gives more optimal and faster control. Furthermore MPC can handle different control cases much better, without changing the settings. On the other hand PID requires considerable fewer amounts of calculations and memory. In one case that has been examined, MPC requires 40 times more amounts of calculations than PID. To be able to control a non-linear system, both MPC and PID must be implemented in several different working points. Furthermore decoupling must be used in the PID-controller to be able to manage cross-connections that seems to be a very important problem.</p>

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