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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.
471

Capacity and lifetime analysis of pre-stressed slatted floors / Kapacitetskontroll och livslängdsundersökning av förspända spaltstavar

Hermansson, Denise, Nilsson, Olivia January 2016 (has links)
This study investigates the mechanical differences between old and newly produced slatted floors through a four-point bending test. To understand to what extent the actual environment has affected the slatted floors, the carbonation depth and corrosion will be examined. The tests showed no mechanical differences between slatted floors which had been in service for a certain amount of years and newly produces ones. Corrosion could be observed on some of the samples but it was not because of the carbonation process. When comparing the calculations of reinforced and pre-stressed concrete slatted floors, the result showed that the pre-stressed floor could carry up to double the load of what the reinforced slatted floor could. The conclusion of this study is, that the pre-stressed slatted floors will certainly hold for at least thirty years and will most likely hold for many years to come.
472

Ectoparasite assemblage of the four-striped mouse, Rhabdomys pumilio : the effect of anthropogenic habitat transformation and temporal variation

Van der Mescht, Luther 03 1900 (has links)
Thesis (MScConsEcol)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Anthropogenic habitat transformation and subsequent fragmentation of natural vegetation is regarded as one of the largest threats to biodiversity in the world. The Cape Floristic Region (CFR) in the Western Cape Province of South Africa is classified as a biodiversity hotspot due to its high plant species diversity and endemism. Increasing growth in agricultural activities in this region has contributed to fragmentation of pristine natural vegetation. A diverse assemblage of small mammal species are found in this region, but very little is known with regard to their ectoparasite diversity. More importantly, no information is available on the effect of fragmentation on parasite burdens or species assemblages. The aims of the study were first to record relative density, average body size and body condition of an endemic rodent, Rhabdomys pumilio, trapped in two habitat types (pristine natural areas and remnant fragments). Secondly, compare diversity and species composition of ectoparasite species on this rodent in the two habitat types. In addition, body size measurements of the two most abundant flea species were recorded and compared for the two habitat types. Lastly, temporal variation in mean abundance of fleas, mites, ticks and the louse were recorded within a habitat fragment surrounded by vineyards. Three hundred and ten individuals of the Four-striped mouse, R. pumilio, were trapped and euthanized at 8 localities (4 remnant habitat fragments and 4 pristine natural areas) in the CFR. All ectoparasites were removed and identified. A total of 8361 ectoparasites that consisted of 6 flea, 1 louse, 8 mites and 11 tick species were recorded. Mites and fleas were found to be more abundant on mice during cool wet months, whereas ticks and the louse were more abundant during the hot dry months of the year. Rodent host body size was larger and they were in better body condition in remnant fragments compared to pristine natural localities. A positive body size relationship was found between the flea, Listropsylla agrippinae, and the host, with larger fleas recorded on rodents that occur in fragments. Mean abundance and prevalence of overall ectoparasites combined and separately for ticks, mites, louse and fleas were higher in fragments compared to natural localities. The study shows that R. pumilio is host to a large diversity of ectoparasite species in the CFR. Moreover, habitat fragments within agricultural landscapes can facilitate higher parasite burdens and prevalence in rodent populations. This can lead to an increase in disease risk given that several of the parasite species are important vectors of pathogens that can cause disease in domestic, wild animals and humans. / AFRIKAANSE OPSOMMING: Menslike habitat transformasie en die daaropvolgende fragmentasie van natuurlike plantegroei word beskou as een van die grootste bedreigings vir biodiversiteit in die wêreld. Die Kaap Floristiese Streek (KFS) in die Wes-Kaap Provinsie van Suid-Afrika word geklassifiseer as 'n biodiversiteit ‘hotspot’ as gevolg van sy hoë plant spesies diversiteit en endemisme. Toenemende groei in landbou-aktiwiteite in hierdie streek het ook bygedra tot die fragmentasie van ongerepte natuurlike plantegroei. 'n Diverse versameling van die klein soogdier spesies word in hierdie streek aangetref, maar baie min is bekend met betrekking tot hul ektoparasiet diversiteit. Meer belangrik, geen inligting is beskikbaar oor die effek van fragmentasie op parasietladings of spesie samestelling nie. Die doel van die studie was eerstens om relatiewe digtheid, gemiddelde liggaams grootte en kondisie van Rhabdomys pumilio aan te teken vir twee habitat tipes (ongerepte natuurlike area en oorblyfsel fragment). Tweedens was die diversiteit en spesiesamestelling van ektoparasiete op R. pumilio vergelyk vir die twee habitat tipes. Daarna was die liggaams grootte metings van die twee mees volopste vlooi spesies aangeteken en vergelyk vir die twee habitat tipes. Laastens was die seisonale variasie van die gemiddelde hoeveelheid vlooie, myte, bosluise en die luis aangeteken binne 'n habitat fragment omring deur wingerde. Drie honderd en tien individue van die vier-gestreepte muis, R. pumilio, was gevang op 8 plekke (4 oorblyfsel habitat fragmente en 4 ongerepte natuurlike areas) in die KFS en daarna was die diere uitgesit. Alle ektoparasiete was verwyder en geïdentifiseer. 'n Totaal van 8361 ektoparasiete wat bestaan het uit 6 vlooie, 1 luis, 8 myte en 11 bosluis spesies was aangeteken. Myte en vlooie gevind was meer volop op muise tydens die koel nat maande, terwyl bosluise en die luis meer volop was gedurende die warm droë maande van die jaar. Knaagdier gasheer liggaam was groter en in 'n beter kondisie in die habitat fragmente in vergelyking met ongerepte natuurlike areas. 'n Positiewe liggaam grootte verwantskap was tussen die vlooi, Listropsylla agrippinae, en die gasheer gevind, met groter vlooie aangeteken op knaagdiere wat voorkom in fragmente. Gemiddelde hoeveelheid en voorkoms van die totale ektoparasiete gekombineer en afsonderlik vir bosluise, myte, die luis en vlooie was hoër in fragmente in vergelyking met natuurlike areas. Die studie toon dat R. pumilio gasheer is vir 'n groot verskeidenheid van ektoparasiet spesies in die KFS. Daarbenewens kan habitat fragmente binne landbou landskappe hoër parasietladings en voorkoms in knaagdier bevolkings fasiliteer. Dit kan lei tot 'n toename in siekte risiko, gegee dat verskeie van die parasietspesies belangrike vektore is van patogene wat siektes kan veroorsaak in huishoudelike, wilde diere en die mens.
473

Of Proofs, Mathematicians, and Computers

Yepremyan, Astrik 01 January 2015 (has links)
As computers become a more prevalent commodity in mathematical research and mathematical proof, the question of whether or not a computer assisted proof can be considered a mathematical proof has become an ongoing topic of discussion in the mathematics community. The use of the computer in mathematical research leads to several implications about mathematics in the present day including the notion that mathematical proof can be based on empirical evidence, and that some mathematical conclusions can be achieved a posteriori instead of a priori, as most mathematicians have done before. While some mathematicians are open to the idea of a computer-assisted proof, others are skeptical and would feel more comfortable if presented with a more traditional proof, as it is more surveyable. A surveyable proof enables mathematicians to see the validity of a proof, which is paramount for mathematical growth, and offer critique. In my thesis, I will present the role that the mathematical proof plays within the mathematical community, and thereby conclude that because of the dynamics of the mathematical community and the constant activity of proving, the risks that are associated with a mistake that stems from a computer-assisted proof can be caught by the scrupulous activity of peer review in the mathematics community. Eventually, as the following generations of mathematicians become more trained in using computers and in computer programming, they will be able to better use computers in producing evidence, and in turn, other mathematicians will be able to both understand and trust the resultant proof. Therefore, it remains that whether or not a proof was achieved by a priori or a posteriori, the validity of a proof will be determined by the correct logic behind it, as well as its ability to convince the members of the mathematical community—not on whether the result was reached a priori with a traditional proof, or a posteriori with a computer-assisted proof.
474

Instrumentation d'un four pilote pour la cuisson de génoise

Douiri, Imen 31 January 2007 (has links) (PDF)
La cuisson de produits céréaliers provoque des transformations physicochimiques dans la pâte pour lui conférer une structure, une texture, une forme, une couleur et un goût désirés. Un four pilote électrique avec circulation d'air chaud a été instrumenté pour suivre en continu la cuisson d'un produit type génoise (700g) placé dans un moule : perte de poids, profil de température interne et température de surface, pression interne. A travers une fenêtre dans la paroi isolée du moule des images ont été enregistrées pour suivre le gonflement. L'évolution de masse volumique a été déduite. Des mesures de flux de chaleur radiatif et convectif reçus par la surface du produit ont contribué à expliquer la coloration de la surface et la forme du produit cuit. Des cuissons à 160, 180, 220°C ont été réalisées avec une perte de masse constante (eau) de 6% durant la période de chauffage, avec des temps de chauffage respectivement de 81, 71, 52 min. Durant cette période la pâte se transforme en croûte colorée sèche en surface, et mie humide. La période de refroidissement contrôlé avec ventilation d'air (90min) conduit à une perte additionnelle de poids de 6% et représente une phase importante pour stabiliser la structure.
475

The social effects of resource decisions : a modeling approach

Oswald, Eric B. January 1976 (has links)
Coal-fueled energy development in the Southwest has resulted in a controversy over claims of environmental damage and spiritual and social disruption to the Native American inhabitants of the region. Development has been supported through estimates of the economic benefits that will accrue to the Hopi and Navajo through the planned development. This research has developed a modeling approach to systematically and rationally assess the impacts of energy development on the Hopi and Navajo Tribes. The model incorporates a simulation technique that describes the Indian social systems over time with and without energy development. The variations within the system without energy development and with various levels of development allow insights into impacts. Computer control allows the model to consider many different decisions relative to energy development, and incorporated graphics allow for efficient and fast impact interpretation. The results of the model indicate that proposed impacts on the Native Americans have been exaggerated. Neither the economic impacts nor spiritual disruptions claimed are seen to occur. The model is seen to be a valuable tool for systematic analysis and the presentation of social impact information.
476

Įvairių veislių rapsų aliejaus tribologinių savybių vertinimas / Evaluation of Tribological Properties of Different Varieties of Rapeseed Oil

Legerpušis, Mindaugas 16 June 2014 (has links)
Skirtingos rapsų veislės skiriasi sėklų aliejingumu ir chemine sudėtimi (riebalų, baltymų, eruko rūgšties, gliukozinolatų kiekis). Todėl, remiantis sėklų sudėties skirtumais, galima iškelti hipotezę, kad ir šių veislių aliejų tribologinės savybės bus skirtingos. Tyrimų tikslas - ištirti kai kurių rapsų veislių aliejaus tribologines savybes bei įvertinti šiuos skirtumus. Šiame darbe atlikti įvairių veislių rapsų aliejaus tribologinių savybių vertinimo tyrimai bei aptariami gauti rezultatai. Tirtas grynas ir specialiais alyvų priedais modifikuotas rapsų aliejus: 1 % antioksidacinio priedo LZ 5150C ir 3 % antifrikcinio ir antidiliminio priedo LZ 5399. Tyrimų rezultatai rodo, kad skirtingų veislių rapsų aliejus pasižymi skirtingomis tribologinėmis savybėmis. Šias savybes galimai pagerina didesnis polinesočiųjų riebiųjų rūgščių kiekis. Rapsų aliejus, modifikuotas įvardintais priedais, visoms tirtoms veislėms efektyviai slopina dilimą ir trintį. Gautus darbo rezultatus bus galima naudoti parenkant biologinės kilmės bazines žaliavas bioalyvoms rapsų aliejaus pagrindu. / There is known different oiliness and chemical composition of seeds depending on rapeseed varieties (fat, protein, erucic acid, glucosinolate content). Therefore, based on seed composition differences, possible hypothesis, that the different varieties of rapeseed oil tribological properties may have differences. The aim of research is to explore tribological properties and evaluate their differences of few different varieties of rapeseed oil. At this work there are accomplished researches of evaluation of different varieties rapeseed oil tribological properties. Pure and modified with special additives rapeseed oil has been studied: used 1% oxidation inhibitors LZ 5150C and 3% anti-friction additives LZ 5399. The results show that the different varieties of rapeseed oil have different tribological properties. These properties can be improved by more polyunsaturated fatty acids. Modified with specified additives rapeseed oil effectively inhibited wear and friction for all investigated varieties. The obtained results in this work will be used in searches for new or upgrading an existing basic raw bio-oil.
477

Aristotle on the matter of the elements

Crowley, Timothy James January 2009 (has links)
This thesis is an investigation into the simplest material entities recognised by Aristotle's theory of nature. In general, the position I defend is that the four 'so-called elements' fire, air, water, and earth are, for Aristotle, genuine elements, i.e., the simplest material constituents, of bodies. In particular, I deal with two problems, the first concerning the relationship between the four 'so-called elements' and the primary contraries, hot-cold, dry-wet; and the second concerning the nature of the matter from which the latter come to be. Responses to these problems in the secondary literature tend to conclude that the contraries (usually together with 'prime matter'), are constitutive of the so-called elements. I reject this conclusion. In the first part of this thesis I consider, and dismiss, the alleged evidence that Aristotle denies to fire, air, water, and earth the status of genuine elements, and I argue that the status of the contraries as the differentiae of the elements effectively rules out the possibility that they could be the constituents of the latter. In the second part of this thesis I attempt to unpack Aristotle's assertion at De Gen. et Cor. II. 1 that the matter of the perceptible bodies is that from which the so-called elements come to be. I argue that the matter of the perceptible bodies, although it is that from which the elements come to be, is not the 'matter of the elements', in the sense of a matter that composes the elements. On the contrary, the 'matter of the perceptible bodies', i.e., the constitutive matter of composite bodies, is itself composed of the elements: it is a mixture of the four elements. Thus the latter can be said to come to be 'from' the 'matter of the perceptible bodies', but this must be understood in a non-constitutive sense of 'from'.
478

Reaching for Understanding: Exploring the Potential of Four-Year-Old Children to Understand Works of Art

Smith, Maria Carmen 05 1900 (has links)
This study was designed to examine how four-year-old children might be able to respond and interpret works of art. Informed by Jean Piaget's and Lev Vygotsky's theories of cognitive development, and building on Micheal Parsons' and Abigail Housen's theories of aesthetic development, the study investigated whether or not four-year-olds are able to expand their initial responses to achieve deeper levels of understanding about works of art.
479

Regionala överenskommelser & kommunal fysisk planering : Regionplanering bortom reglering

Eriksson, David January 2016 (has links)
Denna uppsats utgår från att studera hur kommunal fysisk planering förhåller sig till och tillämpar regionala överenskommelser avseende fysisk struktur. I uppsatsen studeras ett fall av soft planning med ett integrerat perspektiv av Callons (1986) beskrivning med etablerandet av nätverk och hur aktörer associerar sig till nätverket. Detta kompletteras med skapandet av självklarheter genom black boxes och planeringsdoktriner. Kontexten som undersöks är Rådslagsprocessen som Göteborgsregionens kommunalförbund (GR) och dess 13 medlemskommuner ingår i. Tre ingångsvinklar styr uppsatsen: (1) Hur kommunerna förhåller sig till de regionala överenskommelserna och hur de tillämpar dessa. (2) Vilket värde som tillskrivs de regionala överenskommelserna av kommunpolitiker och tjänstemän. (3) Hur lokalt demokratiskt inflytande i den fysiska planeringen påverkas av regionala överenskommelser. I uppsatsen tillämpas två tillvägagångssätt för datainsamlingen: (1) En dokumentstudie där urvalet utgår från att det kan antas finnas ett utmanande mellan kommunernas fysiska planering och överenskommelserna. (2) Semistrukturerade intervjuer med kommunpolitiker och tjänstemän på kommuner. En kvalitativ innehållsanalys utgörs uppsatsens analysmetod. Av empirin kan det märkas att de regionala överenskommelserna ger en huvudinriktning på kommunernas planering. Kommunerna väljer att göra avsteg när de önskar göra det. Det uttrycks ett ansvar gentemot de andra medlemskommunerna att överenskommelserna ska vara en huvudinriktning för deras fysiska planering. Hedersfrågan att hålla överenskommelserna verkar stabilisera kommunernas förhållande och tillämpning av dem. Av de tre överenskommelserna som fattats inom Rådslagsprocessen får den regionala strukturbilden ett särskilt genomslag. Det förefaller som att strukturbildens rumsliga uttryck tillsammans med dess språkliga dimension gör att en identitetsanknytning etableras hos kommunerna. Soft planning får en känslig karaktär då det handlar om hur enskilda individer anknyter sig till det skapade rummet. I detta fall handlar det om hur politiker associerar sig till överenskommelserna, då det uttrycks att överenskommelserna främst är en fråga för den politiska sfären. Förhållningssättet och tillämpningen av överenskommelserna riskerar att utsättas för en destabilisering när nya förtroendevalda ska anknytas till överenskommelserna. Det verkar alltså finnas ett samband med att arbete genom soft planning i framtiden kräver ännu mer arbete inom upprättat soft space, för att individerna ska anknyta sig till det skapade rummet. Soft planning verkar därför präglas av ett inneboende bäst före datum. Genom att överenskommelserna är strikt politiskt tillägnade är tillträdet för invånare begränsat. Informanterna uttrycker att det lokala demokratiska inflytandet sker genom att medborgare väljer ut politiker i kommunvalen, som sedan tillsätts i kommunalförbundet. Överenskommelserna har därför definierat huvudinriktningen på kommunernas fysiska planering innan invånare får möjlighet till att delta. Det ställer frågor om hur ansvarsutkrävandet från väljarna gentemot politikerna säkerställs, vilket hamnar i en komplex situation. Politikerna uttrycks vara ansvariga gentemot sina väljare. I samma stund är de ansvariga gentemot de andra folkvalda politikerna från medlemskommunerna att de ingågna överenskommelserna ska hållas. En möjlig konflikt kan uppstå i ansvarsutkrävandet när politiker behöver tillgodose en lojalitet gentemot sina väljare och en annan till politiker från medlemskommunerna. Väljarnas möjligheter att utkräva ansvar riskerar därför att bli begränsat.
480

Energy and Archetype: A Jungian Analysis of The Four Zoas by William Blake

Hamilton, Lee T. 08 1900 (has links)
The purpose of this study is to examine the parallels between the tenets of Carl Jung's psychology and the mythopoeic structure of Blake's poem, The Four Zoas. The investigation is divided into three chapters. The first deals with the major conceptual parallels between the intellectual systems of the two men. The second is a detailed analysis of the poem, and the third concludes the study by discussing the originality of Blake's thought. Blake anticipated much of Jung's psychology. The parallels between the two are so strong that each man seems to corroborate and validate the opinions and insights of the other. The extent to which he foreshadows Jung reveals Blake to be one of the most original thinkers of any period of time.

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