58 research outputs found

    Comparison of static incubation versus physiologic perfusion techniques for quantitation of luminal release of prostacyclin and thromboxane in canine arteries and veins

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    Intraluminal release of 6-keto-PGF1[alpha] and TxB2 in ex vivo canine arteries and veins was assessed during five consecutive 15-min periods using static incubation and physiologic perfusion techniques. Arterial segments were perfused with 90 ml/min pulsatile flow at 100 mm Hg and vein segments with 90 ml/min nonpulsatile flow at 7 mm Hg. During the final 15-min period vessels were stimulated with arachidonic acid (AAS). Perfusion of vein segments caused a higher release of 6-keto-PGF1[alpha] during the first 30 min (P P 1[alpha] for 45 min (P P 2 release was higher during the entire observation period in perfused arteries and veins compared to incubated vessels (P and 1[alpha] or TxB2 released when comparing values obtained by one technique to values obtained by the other (P> 0.1). These data suggest that flow related shear stress alters vascular prostanoid production, and that such should be accounted for when interpreting results of studies on prostacyclin and thromboxane release from intact vessels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27222/1/0000226.pd

    Earthing of propeller shaft : Concept development for low maintenance shaft earthing device

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    Detta masterprojekt genomfördes pĂ„ Rolls-Royce AB (nu kĂ€nt som Kongsberg Maritime per 1 april 2019) i Kristinehamn, Sverige. Avhandlingen fokuserar pĂ„ att utveckla en jordningsutrustning för propelleraxlar som krĂ€ver lĂ„gt underhĂ„ll till företagets nya poddrivna framdrivningssystem. MĂ„nga elektriska maskiner med roterande axlar utsĂ€tts för skador pĂ„ grund av flödet av elektriska laddningar genom axeln och komponenter med hög resistanselektrisk kontakt. Det Ă€r dĂ€rför viktigt att mildra denna inducerad axelspĂ€nning, antingen genom isolering eller genom att Ă€ndra urladdningsvĂ€gen. Avhandlingen syftar till att identifiera konceptlösningar för jordning av propelleraxlar som Ă€r kostnadseffektiva, krĂ€ver lĂ„gt underhĂ„ll och uppfyller prestandakraven faststĂ€llda av företaget. En systematisk utvecklingsprocess anvĂ€nds över hela projektet som bestĂ„r av fyra huvudaktiviteter. Den första aktiviteten Ă€r att skapa en kravspecifikation baserat pĂ„ information frĂ„n kunder, förstudie och kunskapssökning. Förundersökningen genererade en grundlĂ€ggande kunskapsbas för olika jordningsmetoder och de tribologiska aspekterna för glidande elektrisk kontakt. Den andra aktiviteten bestĂ„r av att generera koncept genom att ta fram huvudlösningar och dellösningar för varje genererat koncept baserat pĂ„ kriterierna i den framtagna kravspecifikationen. För att underlĂ€tta processen Ă€r huvuduppgiften för enheten indelad i tvĂ„ kategorier, en med fokus pĂ„ kontaktmetod och den andra montering av enheten. Den tredje aktiviteten Ă€r utvĂ€rdering och poĂ€ngsĂ€ttning av utvecklade lösningar för att göra det slutliga konceptet. Den fjĂ€rde och sista aktiviteten Ă€r att skapa en produktbeskrivning av det valda konceptet baserat pĂ„ layout och detaljerade tekniska aspekter. De slutliga resultaten av avhandlingen Ă€r en produktbeskrivning av ett "Multiple fiber brushes" jordningsenhetskoncept, med en lösning pĂ„ hur man optimerar design och prestanda parametrar för en viss specifik slitstyrka. En grundlĂ€ggande konstruktionslösning presenteras med optimerade prestandaparametrar som Ă€r lĂ€mpliga för prestandakraven i företagets nya poddrivna framdrivningssystem. Tre framtida projekt kan tas fram frĂ„n resultaten av denna avhandling. Dessa potentiella projekt kan mer ingĂ„ende titta pĂ„ den strukturella utformningen av jordningsanordningen, val av komponentmaterial och praktisk prestationstestning av en fiberborste prototyp.This master thesis project has been done at Rolls-Royce AB (now known as Kongsberg Maritime as of April 1st2019) located in Kristinehamn, Sweden. The focus of the thesis is to develop a low maintenance propeller shaft earthing device for the company’s new podded propulsion system. Many electrical machines with a rotating shaft are exposed to damage due to the flow of electrical charges through the shaft and components with high resistance electrical contact. It is therefore important to mitigate this induced shaft voltage either by insulation or by altering the discharge path.  The thesis purpose is to identify concept solutions for earthing of propeller shafts that are cost effective, requires low levels of maintenance and fulfills performance requirements. A systematic development process is used throughout the project, which consists of four main activities. The first activity is to create a requirement specification from customer input, pre-study and knowledge search. The pre-study generated a fundamental base of knowledge for different earthing methods and the tribological aspects for sliding electrical contact.  The second activity is generating concepts by deriving main solutions and sub-solutions for each generated concept based on the criteria in the developed requirement specification. To make the process easier the main function of the device is divided into two categories, one focusing on contact method and the other assembly.  The third activity is evaluation and scoring of developed solutions to make the final concept selection. The fourth and final activity is to create a product description of the selected concept based on layout and detailed engineering aspects. The final results of the thesis is a product description of a  “multiple fiber brushes” earthing device concept, with a solution on how to optimize design and performance parameters for a certain specific wear rate. A fundamental construction solution is presented with optimized performance parameters suitable for the performance demands of the company’s new podded propulsion system. Three future projects could be extracted from the results of this thesis. These potential projects will in more detail focus on the structural design of the earthing device, component material selection and practical performance testing of a fiber brush prototype

    Earthing of propeller shaft : Concept development for low maintenance shaft earthing device

    No full text
    Detta masterprojekt genomfördes pĂ„ Rolls-Royce AB (nu kĂ€nt som Kongsberg Maritime per 1 april 2019) i Kristinehamn, Sverige. Avhandlingen fokuserar pĂ„ att utveckla en jordningsutrustning för propelleraxlar som krĂ€ver lĂ„gt underhĂ„ll till företagets nya poddrivna framdrivningssystem. MĂ„nga elektriska maskiner med roterande axlar utsĂ€tts för skador pĂ„ grund av flödet av elektriska laddningar genom axeln och komponenter med hög resistanselektrisk kontakt. Det Ă€r dĂ€rför viktigt att mildra denna inducerad axelspĂ€nning, antingen genom isolering eller genom att Ă€ndra urladdningsvĂ€gen. Avhandlingen syftar till att identifiera konceptlösningar för jordning av propelleraxlar som Ă€r kostnadseffektiva, krĂ€ver lĂ„gt underhĂ„ll och uppfyller prestandakraven faststĂ€llda av företaget. En systematisk utvecklingsprocess anvĂ€nds över hela projektet som bestĂ„r av fyra huvudaktiviteter. Den första aktiviteten Ă€r att skapa en kravspecifikation baserat pĂ„ information frĂ„n kunder, förstudie och kunskapssökning. Förundersökningen genererade en grundlĂ€ggande kunskapsbas för olika jordningsmetoder och de tribologiska aspekterna för glidande elektrisk kontakt. Den andra aktiviteten bestĂ„r av att generera koncept genom att ta fram huvudlösningar och dellösningar för varje genererat koncept baserat pĂ„ kriterierna i den framtagna kravspecifikationen. För att underlĂ€tta processen Ă€r huvuduppgiften för enheten indelad i tvĂ„ kategorier, en med fokus pĂ„ kontaktmetod och den andra montering av enheten. Den tredje aktiviteten Ă€r utvĂ€rdering och poĂ€ngsĂ€ttning av utvecklade lösningar för att göra det slutliga konceptet. Den fjĂ€rde och sista aktiviteten Ă€r att skapa en produktbeskrivning av det valda konceptet baserat pĂ„ layout och detaljerade tekniska aspekter. De slutliga resultaten av avhandlingen Ă€r en produktbeskrivning av ett "Multiple fiber brushes" jordningsenhetskoncept, med en lösning pĂ„ hur man optimerar design och prestanda parametrar för en viss specifik slitstyrka. En grundlĂ€ggande konstruktionslösning presenteras med optimerade prestandaparametrar som Ă€r lĂ€mpliga för prestandakraven i företagets nya poddrivna framdrivningssystem. Tre framtida projekt kan tas fram frĂ„n resultaten av denna avhandling. Dessa potentiella projekt kan mer ingĂ„ende titta pĂ„ den strukturella utformningen av jordningsanordningen, val av komponentmaterial och praktisk prestationstestning av en fiberborste prototyp.This master thesis project has been done at Rolls-Royce AB (now known as Kongsberg Maritime as of April 1st2019) located in Kristinehamn, Sweden. The focus of the thesis is to develop a low maintenance propeller shaft earthing device for the company’s new podded propulsion system. Many electrical machines with a rotating shaft are exposed to damage due to the flow of electrical charges through the shaft and components with high resistance electrical contact. It is therefore important to mitigate this induced shaft voltage either by insulation or by altering the discharge path.  The thesis purpose is to identify concept solutions for earthing of propeller shafts that are cost effective, requires low levels of maintenance and fulfills performance requirements. A systematic development process is used throughout the project, which consists of four main activities. The first activity is to create a requirement specification from customer input, pre-study and knowledge search. The pre-study generated a fundamental base of knowledge for different earthing methods and the tribological aspects for sliding electrical contact.  The second activity is generating concepts by deriving main solutions and sub-solutions for each generated concept based on the criteria in the developed requirement specification. To make the process easier the main function of the device is divided into two categories, one focusing on contact method and the other assembly.  The third activity is evaluation and scoring of developed solutions to make the final concept selection. The fourth and final activity is to create a product description of the selected concept based on layout and detailed engineering aspects. The final results of the thesis is a product description of a  “multiple fiber brushes” earthing device concept, with a solution on how to optimize design and performance parameters for a certain specific wear rate. A fundamental construction solution is presented with optimized performance parameters suitable for the performance demands of the company’s new podded propulsion system. Three future projects could be extracted from the results of this thesis. These potential projects will in more detail focus on the structural design of the earthing device, component material selection and practical performance testing of a fiber brush prototype

    HÄllbar intensifiering av den svenska spannmÄlsodlingen

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    The natural environment will become an increasingly important arena for economic competition in the future. The growing world population and the increased global consumption raise concerns about the sustainability of the current and future use of natural resources. Due to the growing global population the production of agricultural crops and food security is high on the global policy agenda. The purpose of this study has been to investigate the opportunities for a sustainable intensification in the Swedish cereals production and how the LantmĂ€nnen cooperative, a company active in the whole cereals value chain can act in order to enable the intensification. The research was conducted as a descriptive case study. Given the comprehensive nature of the purpose of this study, we have studied the Swedish agriculture from a system perspective in order to get the comprehensive understanding of its complexity. The findings presented in this report are based on data from multiple research methods such as interviews with stakeholder in the agriculture, database search, and archive searches. We show in this study that a sustainable intensification of the Swedish cereals production can be realized through utilizing the existing unused farmland registered by the farmer as fallow for a number of consecutive years in a row, which can be described as acreage that is not used for crop production but is still kept in farmable condition. Our study has identified four barriers hindering the intensification; Single payment system, Leasing contract, Logistics and Investment costs. To overcome these barriers we argue that the RO PSS business model is appropriate. By using this model LantmĂ€nnen will be able to deliver four different types of values to the farmers. The first value is the intangible value of identity, which let inactive farmers continue to live on their farms while being able to focus on other sources of main income. The second value we name ownerless consumption. This value offers farmers with little capital to start up or expand their production without having to invest in new machinery and equipment. The third value we call safety, which is connected to the barrier of lease contracts identified and the distrust between landowners and tenants. The fourth value, specialization, gives the farmer possibility to leverage overall cereals bulk production by including niche crops. We conclude by arguing that the opportunities for an intensification of the Swedish Cereals production lie in delivering these four values.Naturen kommer i framtiden bli en alltmer viktig arena för ekonomisk konkurrens. En vĂ€xande vĂ€rldsbefolkning och en ökad global konsumtion skapar oro kring hĂ„llbarheten i vĂ„rt anvĂ€ndande av naturresurser. PĂ„ grund av den ökande befolkningsmĂ€ngden placerar sig frĂ„gor sĂ„som produktionen av jordbruksgrödor och livsmedelsförsörjning högt upp pĂ„ den globala politiska dagordningen. Studiens syfte Ă€r att undersöka möjligheter för en hĂ„llbar intensifiering av den svenska spannmĂ„lsodlingen och hur LantmĂ€nnen, ett kooperativt företag som verkar i spannmĂ„lets hela vĂ€rdekedja ska agera för att möjliggöra intensifieringen. Med tanke pĂ„ den övergripande karaktĂ€ren av vĂ„ra frĂ„gestĂ€llningar har vi studerat det svenska jordbruket ur ett systemperspektiv för att fĂ„ en övergripande förstĂ„else av dess komplexitet. Forskningen har genomförts i form av en beskrivande fallstudie. VĂ„ra resultat baseras pĂ„ data frĂ„n flera forskningsmetoder som intervjuer med intressenter inom jordbruket, databassökning, arkivsökning. VĂ„r studie visar att en hĂ„llbar intensifiering av den svenska spannmĂ„lsodlingen kan realiseras genom att utnyttja befintlig oanvĂ€nd jordbruksmark som av jordbrukaren registrerats som trĂ€da i flera Ă„r i följd. TrĂ€da kan beskrivas som jordbruksareal som inte anvĂ€nds till vĂ€xtodling men som fortfarande hĂ„lls i odlingsbart skick. För att fĂ„ denna mark i bruk och dĂ€rmed möjliggöra en intensifiering krĂ€vs det att fĂ„ bukt med fyra identifierade barriĂ€rer inom det svenska jordbrukssystemet; GĂ„rdsstödet, Arrendekontrakt, Logistik och Investeringskostnader. Vi hĂ€vdar, baserat pĂ„ vĂ„ra resultat och analyser, att affĂ€rsmodellkonceptet RO PSS Ă€r lĂ€mplig att anvĂ€nda dĂ„ LantmĂ€nnen ska lyckas fĂ„ bukt med barriĂ€rerna. Denna modell kommer leverera fyra olika vĂ€rden till jordbrukarna. Det första vĂ€rdet har vi döpt till Identitet och Ă€r av en immateriell natur som vilket lĂ„ter inaktiva jordbrukare fortsĂ€tta bo kvar pĂ„ sina gĂ„rdar medan de inriktar sig pĂ„ andra inkomstbaserade verksamheter. Det andra vĂ€rdet gav vi namnet Ägandefri konsumtion. Detta ger vĂ€rde till jordbrukaren i form av att jordbrukaren inte behöver lĂ„na pengar för höga  investeringskostnader i maskiner och infrastruktur vid uppstart eller expansion av verksamheten. Det tredje vĂ€rdet kallar vi för SĂ€kerhet, vilket Ă€r relaterat till barriĂ€ren arrendekontrakt dĂ€r vi har funnet en misstro mellan markĂ€gare och arrendatorer. Det fjĂ€rde vĂ€rdet, Specialisering, ger jordbrukaren möjlighet att blanda in specialgrödor i sin produktion, och pĂ„ sĂ„ vis skapa en hĂ€vstĂ„ng Ă„t bulkproduktionen. VĂ„r slutsats Ă€r att möjligheterna för en intensifiering av den Svenska spannmĂ„lsodlingen ligger i att kunna leverera dessa vĂ€rden

    HÄllbar livsmedelsproduktion : EU:s och Jordbruksverkets mÄl samt svenskajordbrukares uppfattningar om hur ett hÄllbart jordbrukskall bedrivas

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    Under Ă„ren 2007 och 2008 utbröt en global matkris. Kraftigt stigande livsmedelspriser skapade politisk oro i flera delar av vĂ€rlden. FrĂ„gor kring hur vĂ€rldens livsmedelsproduktion ska klara av en vĂ€xande befolkning och förĂ€ndrat klimat i framtiden pĂ„ ett hĂ„llbart sĂ€tt vĂ€cktes. Syftet med denna rapport Ă€r att undersöka vad Europeiska Unionen – EU gör för att frĂ€mja en hĂ„llbar utveckling inom Europas jordbruk – ett sĂ„ kallat hĂ„llbart jordbruk. Rapporten Ă€mnar Ă€ven ge bilden av ett hĂ„llbart jordbruk ur fyra svenska jordbrukares perspektiv, och att undersöka om det finns delade meningar mellan jordbrukare och myndigheter. Teorier bakom begreppen hĂ„llbar utveckling och hĂ„llbart jordbruk beskrivs för att ligga som grund för bedömningen av EU:s och de svenska jordbrukarnas syn pĂ„ hĂ„llbart jordbruk. EU:s jordbrukspolitik och riktlinjer redogörs sedan för ur ett historiskt perspektiv för att ge förstĂ„else för vad som har utformat jordbrukspolitiken som den Ă€r idag. EU planerar att införa nya direktiv under 2013 under namnet CAP14, vilka summeras i samma kapitel. Intervjuer med fyra svenska jordbrukare sammanstĂ€lls sedan och deras syn och Ă„sikter pĂ„ hĂ„llbarhet och hĂ„llbart jordbruk stĂ€lls mot EU:s och jordbruksverkets direktiv i en analys. HĂ€r förs vĂ„ra resonemang in om orsaker till varför det finns meningsskiljaktigheter mellan myndigheterna och jordbrukarna. I arbetets slutsats ger vi vĂ„ra Ă„sikter om vad som vi anser Ă€r hĂ„llbart och inte hĂ„llbart i EU:s och jordbrukarnas syn.Between 2007 and 2008 there was a global food crisis. Great increase in food prices created political unrest in many parts of the world. Questions about how the world's food production should be adapted to cope with a growing population and climate change in the future in a sustainable way arose. The purpose of this report is to investigate what the European Union - EU is doing to promote the sustainable development of agriculture in Europe - a so-called sustainable agriculture. The report is also intended to give the image of sustainable agriculture from four Swedish farmers' perspective, and to investigate if there is disagreement between farmers and authorities. Theories behind the concepts of sustainable development and sustainable agriculture are described to be the basis for the assessment of the EU and the Swedish farmers' approach to sustainable agriculture. EU agricultural policies and guidelines are described from a historical perspective to give an understanding of what has shaped agricultural policy as it is today. The EU is planning to introduce new directives in 2013 under the name CAP14, which are summarized in the same chapter. Interviews with four Swedish farmers are then compiled and their views and opinionson sustainability and sustainable agriculture is compared to the EU and the Board of Agriculture directive in an analysis. Here we add our thoughts into the reasons why there are differences of opinion between authorities and farmers. In the conclusion of the report, we give our opinions on what we believe is sustainable and not sustainable in the EU and farmers vision

    Återbruk av byggnadsmaterial : En litteraturstudie om utmaningar som idag hindrar anvĂ€ndningen av Ă„terbrukade byggnadsmaterial

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    Purpose: This study aims to identify obstacles and challenges that prevent the reuse of building materials and bring forth possible solutions. But also to examine the technical-, economic- and environmental advantages and disadvantages of using reused building materials. Method: The study is based on literatures that have been sustained from scientific articles, interviews and analyses of reference objects. The main study mainly consists of information gathered from scientific articles that have been analysed in a literature study. Information was also gathered from nine interviews that have been done with various professionals that works in the construction industry. Results: Several obstacles that arise when reusing building materials were identified. One of the major barriers is logistics and storage of recycled materials. Furthermore, legal and official requirements, the demolition process, guarantees, quality of the material and insufficient knowledge of those who work or want to work with recycling and material reuse. Based on the reference objects, the survey shows large environmental savings in both reduced carbon footprint and reduction of large amounts of demolition waste. Based on the literature analysis, proposals for solutions have been develop to all the obstacles and risks that have arisen. Conclusions: Finally, there are several obstacles that make it difficult to reuse in the amount that actors desire. Over time, recycling will increasingly become more common, and solutions will come along with it. But more research and more pilot projects will develop knowledge in recycling and facilitate development in general. New legislation promoting or forcing recycling projects will also be needed

    Återbruk av byggnadsmaterial : En litteraturstudie om utmaningar som idag hindrar anvĂ€ndningen av Ă„terbrukade byggnadsmaterial

    No full text
    Purpose: This study aims to identify obstacles and challenges that prevent the reuse of building materials and bring forth possible solutions. But also to examine the technical-, economic- and environmental advantages and disadvantages of using reused building materials. Method: The study is based on literatures that have been sustained from scientific articles, interviews and analyses of reference objects. The main study mainly consists of information gathered from scientific articles that have been analysed in a literature study. Information was also gathered from nine interviews that have been done with various professionals that works in the construction industry. Results: Several obstacles that arise when reusing building materials were identified. One of the major barriers is logistics and storage of recycled materials. Furthermore, legal and official requirements, the demolition process, guarantees, quality of the material and insufficient knowledge of those who work or want to work with recycling and material reuse. Based on the reference objects, the survey shows large environmental savings in both reduced carbon footprint and reduction of large amounts of demolition waste. Based on the literature analysis, proposals for solutions have been develop to all the obstacles and risks that have arisen. Conclusions: Finally, there are several obstacles that make it difficult to reuse in the amount that actors desire. Over time, recycling will increasingly become more common, and solutions will come along with it. But more research and more pilot projects will develop knowledge in recycling and facilitate development in general. New legislation promoting or forcing recycling projects will also be needed

    Effects of extracellular pH on PGI2 and TxA2 release from perfused canine veins

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28426/1/0000209.pd
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