9 resultados para Zr-Sm mixed oxides

em Dalarna University College Electronic Archive


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Ever since Sweden joined EU on the 1st of January 1995 the auditing is regulated not only by our Swedish laws but also by EG:s directives. In the fourth directive the member states are given a possibility to dispense small companies from the duty to audit the accounts. It is up to every member state to decide whether they want to dispense the small companies or not and today Sweden is one of few member states who does not.The purpose of this essay was to describe how lenders and Skatteverket will act in case of a dispensation for small companies from the duty to audit the accounts. The study has been carried out by interviewing four lenders and Skatteverket.The study shows that the lenders and Skatteverkets acting in case of a dispensation for small companies from the duty to audit the accounts will part from each others. While the lenders stand before a big change Skatteverkets work will be next to unaltered.Half the lenders think that they will continue to demand that the companies’ accounts be audited. The other half thinks that they will adjust their demands that the accounts be audited to each specific company. Skatteverket trusts in the increasing number of samples to guarantee the quality with the companies’ financial reports.

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Syftet med detta arbete är att studera vad som händer med förskolebarns kommunikation, samspel och lärande i mötet med det digitala verktyget ipad. I denna undersökning har jag även tittat närmare på hur pedagogen förhåller sig och påverkar situationen. Jag har närmat mig undersökningsområdet med en kvalitativ ansats där jag använt mig av observation som metod. Mina observationer har utförts på en förskola där jag studerat barn och pedagoger på två av förskolans avdelningar, en avdelning med barn i åldern 1-3 år och en avdelning med barn i åldern 3-5 år.Resultatet påvisar att barnen blir språkligt aktiv och engagerade i mötet med ipaden. De kommunicerar och samspelar med varandra på många olika sätt. Studien visar även att barn möter ipaden under tystnad med koncentration och förundran. Pedagogen, kamraterna och ipadens olika applikationer har betydelse för kommunikationen och lärandet. Ipaden är ett lustfyllt verktyg som barnen möter med total orädsla och nyfikenhet. Barnen uppvisar en stor vilja att vara aktiva och interagera med det digitala verktyget och ipaden kan anses vara ett stöd för barns lärande. Förskolan har gett barnen möjligheter att möta och bli språkliga med det digitala verktyget ipad men undersökningen visar också att miljön och pedagogerna begränsar barnen på olika sätt. Slutsatsen av studien är att ipaden kan användas som ett verktyg för att stärka barns kommunikation, samspel och lärande om den används på ett genomtänkt och medvetet sätt i förskolans verksamhet.

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The use of ceramic material as refractories in the manufacturing industry is a common practice worldwide. During usage, for example in the production of steel, these materials do experience severe working conditions including high temperatures, low pressures and corrosive environments. This results in lowered service lives and high consumptions of these materials. This, in turn, affects the productivity of the whole steel plant and thereby the cost. In order to investigate how the service life can be improved, studies have been carried out for refractories used in the inner lining of the steel ladles. More specifically, from the slag zone, where the corrosion is most severe. By combining thermodynamic simulations, plant trails and post-mortem studies of the refractories after service, vital information about the behaviour of the slagline refractories during steel refining and the causes of the accelerated wear in this ladle area has been achieved. The results from these studies show that the wear of the slagline refractories of the ladle is initiated at the preheating station, through reduction-oxidation reactions. The degree of the decarburization process is mostly dependent on the preheating fuel or the environment. For refractories without antioxidants, refractory decarburization is slower when coal gas is used in ladle preheating than when a mixture of oil and air is used. In addition, ladle preheating of the refractories without antioxidants leads to direct wear of the slagline refractories. This is due to the total loss of the matrix strength, which results in a sand-like product. Thermal chemical changes that take place in the slagline refractories are due to the MgO-C reaction as well as the formation of liquid phases from impurity oxides. In addition, the decrease in the system pressure during steel refining makes the MgO-C reaction take place at the steel refining temperatures. This reduces the refractory’s resistance to corrosion. This is a serious problem for both the magnesia-carbon and dolomite-carbon refractories. The studies of the reactions between the slagline refractories and the different slag compositions showed that slags rich in iron oxide lead mostly to the oxidation of carbon/graphite in the carbon-containing refractories. This leads to an increased porosity and wettability and therefore an enhanced penetration of slag into the refractory structure. If the slag contains high contents of alumina and or silica (such as the steel refining slag), reactions between the slag components and the dolomite-carbon refractory are promoted. This leads to the formation of low-temperature melting phases such as calcium-aluminates and silicates. The state of these reaction products during steel refining leads to an accelerated wear of the dolomite-carbon refractory. The main products of the reactions between the magnesia-carbon refractory and the steel refining slag are MgAl2O4 spinels, and calcium-aluminates, and silicates. Due to the good refractory properties of MgAl2O4 spinels, the slag corrosion resistance of the magnesiacarbon refractory is promoted.

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This paper presents a two-step pseudo likelihood estimation technique for generalized linear mixed models with the random effects being correlated between groups. The core idea is to deal with the intractable integrals in the likelihood function by multivariate Taylor's approximation. The accuracy of the estimation technique is assessed in a Monte-Carlo study. An application of it with a binary response variable is presented using a real data set on credit defaults from two Swedish banks. Thanks to the use of two-step estimation technique, the proposed algorithm outperforms conventional pseudo likelihood algorithms in terms of computational time.

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Uppsatsens syfte är att studera hur estetiska lärprocesser används för att stimulera lärandet och utveckla eleverna på gymnasial nivå i ämnet religionskunskap. För att få svar har under-sökningen fokuserat på hur estetiska lärprocesser iscensätts i praktiken, kopplat till teori om hur dessa lärprocesser kan påverka och stimulera elevens utveckling och lärande. Studien grundar sig på kvalitativa intervjuer gjorda på två olika skolor, en privat skola och en kom-munal med gymnasielärare i ämnet religion. Intervjutexterna har tolkats hermeneutiskt för att inte bara synliggöra samtalet mellan informanter och forskare, utan även belysa den tolkade texten som på så sätt även den kan ses som ett samtal mellan tolkare, läsare och text. Studien har använt ett teoretiskt ramverk där tre teoretiska perspektiv belyst estetiska lärprocesser samt kringliggande problematik i ämnet. Studien är av komparativ art och analysverktygen har selekterats utifrån tanken att med olika teoretikers perspektiv bemöta och besvara studiens frågeställningar.Resultatet påvisar att det råder en tveksamhet om vad som kan betraktas som estetiska lärpro-cesser och vad som ska inkluderas i begreppet bland informanterna. Dock råder en samstäm-mighet i att det rör sig om praktiskt, kreativt engagemang i grupp som kännetecknar estetiken i verksamheten. Värderingsfrågan visade sig ha två dimensioner. Den ena aspekten var att in-formanterna värderade de estetiska lärprocesserna högt som ur motivations-, engagemangs- och personlighetsutvecklande perspektiv. Däremot värderades de estetiska lärprocesserna lågt ur ett betygsgrundande perspektiv.De estetiska lärprocesserna iscensätts främst genom film, möten och miljöbyten. Film an-vänds främst som visuell och känslomässig förstärkning av undervisningens valda innehåll. Möten med personer aktiva inom det aktuella undervisningstemat används i lika stor utsträck-ning för att öka elevernas minnesförnimmelse och engagemang samt verklighetsrelatering, det vill säga koppling till extern kunskap. Möten kunde även i mer abstrakt betydelse innefatta möten med andra, redan befintliga kulturer i dess omgivning som synliggjorts genom den estetiska lärprocessen.Fördelarna med att använda sig av de estetiska lärprocesserna i undervisningen visade sig i huvudsak vara att de skapade utrymme för känslor och att de bidrar till en större studiemoti-vation samt ett ökat engagemang bland eleverna. Respekt för andra människor ur ett sociokul-turellt perspektiv var vad informanterna anser att de estetiska lärprocesserna genererar i ett vidgat lärande perspektiv, det vill säga ett externt lärande. Nackdelarna kan sammanfattas med de bristande resurser som stod till pedagogernas förfogande i form av tid och utbildning i ämnet, vilket i hög grad kom att belysa bedömningsproblematiken.

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This paper presents the techniques of likelihood prediction for the generalized linear mixed models. Methods of likelihood prediction is explained through a series of examples; from a classical one to more complicated ones. The examples show, in simple cases, that the likelihood prediction (LP) coincides with already known best frequentist practice such as the best linear unbiased predictor. The paper outlines a way to deal with the covariate uncertainty while producing predictive inference. Using a Poisson error-in-variable generalized linear model, it has been shown that in complicated cases LP produces better results than already know methods.

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Generalized linear mixed models are flexible tools for modeling non-normal data and are useful for accommodating overdispersion in Poisson regression models with random effects. Their main difficulty resides in the parameter estimation because there is no analytic solution for the maximization of the marginal likelihood. Many methods have been proposed for this purpose and many of them are implemented in software packages. The purpose of this study is to compare the performance of three different statistical principles - marginal likelihood, extended likelihood, Bayesian analysis-via simulation studies. Real data on contact wrestling are used for illustration.

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Background: In light of the multifactorial etiology of fall-related hip fracture, knowledge of fall circumstances may be especially valuable when placed in the context of the health of the person who falls. We aimed to investigate the circumstances surrounding fall-related hip fractures and to describe fall circumstances in relation to participants' health and functional characteristics. Methods: The fall circumstances of 125 individuals (age >= 50 years) with hip fracture were investigated using semi-structured interviews. Data concerning participants' health (comorbidities and medications) and function (self-reported performance of mobility, balance, personal activities of daily living and physical activity, previous falls and hand grip strength) were collected via medical records, questionnaires and dynamometry. Using a mixed methods design, both data sets were analysed separately and then merged in order to provide a comprehensive description of fall events and identify eventual patterns in the data. Results: Fall circumstances were described as i) Activity at the time of the fall: Positional change (n = 24, 19%); Standing (n = 16, 13%); Walking (n = 71, 57%); Balance challenging (n = 14, 11%) and ii) Nature of the fall: Environmental (n = 32, 26%); Physiological (n = 35, 28%); Activity-related indoor (n = 8, 6%) and outdoor (n = 8, 6%); Trips and slips on snow (n = 20, 16%) and in snow-free conditions (n = 12, 10%) and Unknown (n = 10, 8%). We observed the following patterns regarding fall circumstances and participants' health: those who fell i) during positional change had the poorest functional status; ii) due to environmental reasons (indoors) had moderate physical function, but high levels of comorbidity and fall risk increasing medications; iii) in snow-free environments (outdoors) appeared to have a poorer health and functional status than other outdoor groups. Conclusions: Our findings indicate that patterns exist in relation to the falls circumstances and health characteristics of people with hip fracture which build upon that previously reported. These patterns, when verified, can provide useful information as to the ways in which fall prevention strategies can be tailored to individuals of varying levels of health and function who are at risk for falls and hip fracture.