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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.
31

Synthesis of Aza-Heterocyclic Monoamidines as Potential DNA Minor Groove Binders, Anti-Trypanosomals, and Boron Neutron Capture Therapy Agents

Green, Julius 17 December 2014 (has links)
A series of combilexin-like monoamidines has been synthesized by linking an intercalative unit with the DNA minor groove binder DB 818 via “Click chemistry.” DB 818 is a dicationic minor groove binder that has shown strong binding affinity to AT sequences. The aim was to synthesize novel classes of DNA minor groove binders that are combilexin-like – minor groove binder / intercalator hybrid – as potential unique DNA binding agents and therapeutics against African Sleeping Sickness. Additionally, a series of novel benzo[d]1,3,2-diazaboroles DAPI derivatives were also synthesized and investigated. These boron compounds have the potential to be strong DNA minor groove binders because of their lower pKa and act as potential chromophores for Boron Neutron Capture Therapy.
32

SYNTHESIS OF AZA-HETEROCYCLIC MONOAMIDINES AS POTENTIAL DNA MINOR

Green, Julius 17 December 2014 (has links)
A series of combilexin-like monoamidines has been synthesized by linking an intercalative unit with the DNA minor groove binder DB 818 via “Click chemistry.” DB 818 is a dicationic minor groove binder that has shown strong binding affinity to AT sequences. The aim was to synthesize novel classes of DNA minor groove binders that are combilexin-like – minor groove binder / intercalator hybrid – as potential unique DNA binding agents and therapeutics against African Sleeping Sickness. Additionally, a series of novel benzo[d]1,3,2-diazaboroles DAPI derivatives were also synthesized and investigated. These boron compounds ave the potential to be strong DNA minor groove binders because of their lower pKa and act as potential chromophores for Boron Neutron Capture Therapy.
33

THE EFFECT OF SEED TEMPERING AND MICRONIZATION TEMPERATURE ON THE PHYSICOCHEMICAL PROPERTIES OF CHICKPEA FLOUR AND ITS PERFORMANCE AS A BINDER IN LOW-FAT PORK BOLOGNA

2014 April 1900 (has links)
The overall goal of this research was to investigate the effect of seed tempering moisture and micronization temperature on the physicochemical properties of chickpea flour and its subsequent performance as a binder in a model low-fat pork bologna product. This work was divided into three studies. In the first study, the effect of seed tempering moisture (untempered (7% moisture) or tempered to 15 or 22% moisture) and surface micronization temperature (115, 130, 150 or 165oC) and on the physical, chemical and functional properties of chickpea flour were investigated. Chickpea flour became darker as seed moisture or micronization temperature increased. Increasing the micronization temperature at 22% seed moisture increased starch gelatinization from 8.2 to 34.0%. The lipoxygenase activity of chickpea flour also was reduced by micronization of seed. Lipoxygenase activity in flour from non-micronized seed and flour from seed micronized at 115oC without tempering was determined to be 1.98×105 and 1.12×105 units/g of protein, respectively, with no activity found in any other treatments. There was an increase in the water holding (WHC) and oil absorption capacity (OAC) of flour when chickpea seed was tempered to 22% moisture before micronization. Flour from untempered seed and from seed tempered to 15% moisture exhibited small increases in WHC as micronization temperature increased. Micronization had no effect on the OAC of untempered flours, whereas OAC decreased in flour from seed tempered to 15% moisture at higher micronization temperatures. Rapid visco-analysis (RVA) revealed that peak viscosity and final viscosity of all flours from tempered seed decreased with increasing micronization temperature, whereas the trend for both peak viscosity and final viscosity was in the opposite direction with untempered seed. The effect of seed tempering moisture and micronization temperature on the performance of chickpea flour as a binder in a low-fat, comminuted meat product (i.e., low-fat bologna) was investigated in study 2. Both the textural and sensory properties (trained sensory panel, n=12) of the bologna (10% fat) were explored. In study 3, a consumer panel was performed with 101 untrained participants evaluating selected formulations in order to better understand consumer purchasing behaviour as it relates to comminuted meat products containing a pulse-based binder. Bologna containing flour from micronized chickpea was more yellow in colour (CIE system, trained panel and consumer panel evaluation) compared to those with added wheat flour or no binder. There was no effect of tempering or micronization conditions on cook loss or expressible moisture of bologna containing chickpea flour, whereas bologna produced with wheat flour had the greatest WHC among all bologna treatments. Texture profile analysis (TPA) showed that the addition of chickpea flour from seed tempered to 15% or 22% seed moisture and micronized to 115, 130 or 150oC or flour from untempered seed micronized to 130 or 150oC led to an increase in hardness to a level similar to that of bologna containing wheat flour; sensory evaluation by the trained panel did not produce a similar result. A difference in flavour intensity was not found among all bolognas containing chickpea flour during sensory evaluation. Bologna produced with chickpea flour from seed micronized to 150oC and from seed tempered to 22% moisture and micronized to 115oC was comparable to bologna containing wheat flour with respect to overall texture, overall juiciness and flavour acceptability. These results demonstrated that selection of appropriate seed tempering conditions and micronization temperatures is important with respect to the utilization of chickpea flour as a binder in low-fat bologna.
34

Evaluation of the Effects of Aging on Asphalt Rubber

January 2010 (has links)
abstract: Oxidative aging is an important factor in the long term performance of asphalt pavements. Oxidation and the associated stiffening can lead to cracking, which in turn can lead to the functional and structural failure of the pavement system. Therefore, a greater understanding of the nature of oxidative aging in asphalt pavements can potentially be of great importance in estimating the performance of a pavement before it is constructed. Of particular interest are the effects of aging on asphalt rubber pavements, due to the fact that, as a newer technology, few asphalt rubber pavement sections have been evaluated for their full service life. This study endeavors to shed some light on this topic. This study includes three experimental programs on the aging of asphalt rubber binders and mixtures. The first phase addresses aging in asphalt rubber binders and their virgin bases. The binders were subjected to various aging conditions and then tested for viscosity. The change in viscosity was analyzed and it was found that asphalt rubber binders exhibited less long term aging. The second phase looks at aging in a laboratory environment, including both a comparison of accelerated oxidative aging techniques and aging effects that occur during long term storage. Dynamic modulus was used as a tool to assess the aging of the tested materials. It was found that aging materials in a compacted state is ideal, while aging in a loose state is unrealistic. Results not only showed a clear distinction in aged versus unaged material but also showed that the effects of aging on AR mixes is highly dependant on temperature; lower temperatures induce relatively minor stiffening while higher temperatures promote much more significant aging effects. The third experimental program is a field study that builds upon a previous study of pavement test sections. Field pavement samples were taken and tested after being in service for 7 years and tested for dynamic modulus and beam fatigue. As with the laboratory aging, the dynamic modulus samples show less stiffening at low temperatures and more at higher temperatures. Beam fatigue testing showed not only stiffening but also a brittle behavior. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2010
35

Att konstruera en 3D-skrivare som tillämpar Binder Jetting-teknik

Svensson, Erica, Langkilde, Maria January 2018 (has links)
3D-skrivare är en allt vanligare syn i dagens samhälle. De flesta 3D-skrivarna skriver ut i plast men andra tekniker har också utvecklats, däribland Binder Jetting som är en teknik som används vid utskrifter i pulver. I detta arbete har en skrivare som tillämpar Binder Jetting-teknik byggts. Projektets mål är att kunna skriva ut enklare 3D-modeller. Arbetet bestod av att skruva ihop skrivarens alla delar i metall och plast, tillverka kretskort, koppla elektronik samt ladda över programvara till skrivaren. De kretskort som egentillverkades är specialdesignade för just denna modell. Det ena har som funktion att förstärka spänningen från 12V till 20V samt öka antalet utgångar från Megatronics-kortet. Det andra har som funktion att konvertera en kontakt från en utgång till en annan. Då skrivaren byggts ihop testades den genom att göra en utskrift i 2D. Vid testkörningen i 2D framkom det att bläckpatronen inte skrev ut något bläck. För att lösa problemet påbörjades en felsökning. Det som undersöktes var bläckpatronen, kablar och de egengjorda kretskorten. Under felsökningens gång upptäcktes en kabel som glappade samt två feldragna ledningar på ett av kretskorten. Efter att båda dessa problem blivit åtgärdade kunde skrivaren göra en utskrift i 2D. Nästa steg var att fylla skrivaren med pulver för att testa att skriva ut en 3D-modell i form av en kub. Resultatet blev bläckfärgat pulver då bläcket inte höll ihop gipset. Under slutet av utskriften blev utskriften även skev, det vill säga att varje lager försköts något, så de hamnade inte på varandra. Det kan bero på att stegmotorerna tappar kraft eller att något är fel med filen på SD-kortet som skrivaren hämtar information från. En vidareutveckling av skrivaren är att koppla upp den till wifi för att kunna skicka filer direkt till skrivaren utan att ha ett SD-kort som mellanhand. Ett långsiktigt mål är att utveckla skrivaren så att det kan skriva ut individanpassade läkemedel.
36

Properties of Activated Crumb Rubber

January 2014 (has links)
abstract: ABSTRACT Pre-treated crumb rubber technologies are emerging as a new method to produce asphalt rubber mixtures in the field. A new crumb rubber modifier industrially known as "RuBind" is one such technology. RuBindTM is a "Reacted and Activated Rubber" (RAR) that acts like an elastomeric asphalt extender to improve the engineering properties of the binder and mixtures. It is intended to be used in a dry mixing process with the purpose of simplifying mixing at the asphalt plant. The objectives of this research study were to evaluate the rheological and aging properties of binders modified with RuBindTM and its compatibility with warm mix technology. Two binders were used for this study: Performance Grade (PG) 70-10 and PG 64-22, both modified with 25% by weight of asphalt binder. Laboratory test included: penetration, softening point, viscosity, Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR). Tests were conducted under original, short and long -term aging conditions. Observations from the test results indicated that there is a better improvement when RuBindTM is added to a softer binder, in this case a PG 64-22. For short-term aging, the modified binder showed a similar aging index compared to the control. However, long term aging was favorable for the modified binders. The DSR results showed that the PG 64-22 binder high temperature would increase to 82 °C, and PG 70-10 would be increased to 76 °C, both favorable results. The intermediate temperatures also showed an improvement in fatigue resistance (as measured by the Superpave PG grading parameter |G*|sinä). Test results at low temperatures did not show a substantial improvement, but the results were favorable showing reduced stiffness with the addition of RuBindTM. The evaluation of warm mix additive using EvothermTM confirmed the manufacturer information that the product should have no negative effects on the binder properties; that is the modified binder can be used in a warm mix process. These results were encouraging and the recommendation was to continue with a follow up study with mixture tests using the RuBindTM modified binders. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2014
37

Avaliação da goma gelana como aglutinante em formulações de pellets contendo teofilina / Evaluation of gellan gum as a binding agent in pellet formulations containing theophylline

Eduardo José Barbosa 17 March 2017 (has links)
O objetivo deste trabalho foi desenvolver formulações de pellets contendo teofilina, utilizando a goma gelana como aglutinante. Inicialmente, o uso desse polímero foi avaliado em comparação com o PVP. Por meio de delineamento experimental 32 foram analisadas as variáveis aglutinante e diluente. Os pellets obtidos apresentaram resultados satisfatórios na friabilidade e esfericidade. Verificou-se que o diluente exerceu influência significativa na granulometria, de modo que formulações com manitol apresentaram maior formação de pó após a produção. Com relação ao aglutinante sua maior influência foi na dissolução, pois formulações com gelana apresentaram eficiência de dissolução, em média, menor que as formulações com PVP. A seguir, foi avaliada a influência do polímero, sua quantidade, e seu modo de incorporação nas formulações. Para isso foi realizado um delineamento experimental 23, tendo a gelana, a quantidade, e a incorporação como variáveis. Verificou-se que a característica que sofreu maior influência das variáveis foi a granumoletria, pois as condições empregadas influenciaram significativamente o rendimento de pellets. Com relação à friabilidade, esfericidade e dissolução, não foram observadas diferenças significativas entre os resultados, ainda que algumas tendências puderam ser identificadas. / Aim of this work was to develop pellet formulations containing theophylline, using gellan gum as a binding agent. Inicially, application of the polymer was compared with PVP. By a 32 experimental design, variables binder and diluent were analyzed. Pellets presented satisfactory results in friability and sphericity. It was found that the diluent exerted significant influence on granulometry, so formulations with mannitol showed higher dust formation after production. Regarding binder variable, its higher influence was in the dissolution, since formulations with gellan presented smaller dissolution efficiency than formulations with PVP. Next, the influence of polymer, amount, and incorporation were evaluated. In this part, a 23 experimental design was carried out, with gellan, quantity, and incorporation as variables. It was found that granulometry was the most influenced by variables. So conditions employed influenced significantly the yield of pellets. Regarding friability, sphericity and dissolution, no significant differences were observed, although some trends could be identified.
38

Structural Low Cement Content (LCC) Concrete: An Eco-friendly Alternative for Construction Industry

Yousuf, Saif 07 May 2018 (has links)
Pressure is mounting in the construction industry to adopt more environmentally sustainable methods to reduce CO2 emissions. Portland cement (PC) often constitutes to more than two-thirds of the embodied energy of concrete, and its production generates 5% of global greenhouse gas emissions. One efficient strategy to reduce the cement content without sacrificing performance is the use of particle packing models (PPM) to mix- proportion concrete mixtures with low cement content, the so-called low cement content (LCC) concrete. If on the one hand LCC was seen to be an effective sustainable alternative to the construction industry, its mechanical behaviour, durability and long-term performance are still under debate and thus further research is needed in the area. In this project, continuous PPM theories were used to mix- design structural concrete mixes presenting distinct mechanical properties (i.e. 25 & 35 MPa) and cement contents. Their performance was evaluated in the fresh and hardened states, and gaps, recommendations, and further needs were highlighted. Results show that the use of PPM enables the development of LCC systems, showing impressive hardened state performance (i.e. higher compressive strength and modulus of elasticity and lower electrical resistivity) and low carbon footprint. However, challenges in the fresh state were faced, which may be potentially solved with the use of chemical admixtures, fillers and/or supplementary cementing materials (SCMs).
39

Ověření použitelnosti biogenních pojiv při odlévání odlitků z LLG / Test the applicability of biogenic binders during casting of gray cast iron

Fiala, Vlastimil January 2017 (has links)
The thesis deals with verification of applicability of biogenic binders during casting of gray cast iron. Applicability of these binders for making moulds as well as cores was verificated. The introduction describes strength of cured mixture with biogenic binder including influence of additives and refractory coating. The main part describes process of manufacturing of castings being poured into the biogenic binder bonded moulds. Pouring castings with cores bonded with the same binder is described as well. The last part deals with assessment of the given tests. The thesis comprises photodocumentation of poured samples.
40

Bindemedel i ledningsnät / Binder in Cable Harness

RUGLAND TIMGREN, BEATRICE January 2015 (has links)
Det här projektet har utförts på Scania och är en förstudie till en standardbeskrivning där olika bindemedel i ledningsnät studerats för att kunna användas i olika miljöer i lastbilen så som hytt chassi och drivlina. Olika krav som temperatur, kemikaliebeständighet och fuktresistans ställs för de olika miljöerna. Bindemedlet ska hålla kablarna på plast i en skyddsslang och samtidigt fungera som tätning. De limtyper som har studerats i den här rapporten är ett epoxilim, ett epoxy-cyanoacrylate hybrid lim, ett smältlim av polyamid och två siliconlim. De har limmats på några av de platser som används i lastbilen och sedan utsatts för dragtester, kemikalietester, åldring- och klimattest. Inget av de testade limmerna klarade alla testerna men den limgrupp som klarade testen bäst var de av silicon. / This project has been performed at Scania and it is a pre-study for a standard description of binders in cables harness in different environments in the truck. The different environmental zones are the cab, chassis and power train. Different zones in the truck have different requirements such as temperature, chemicals and moister resistance. The function of the binder is to glue cables into a protective hose of plastic and also act as a seal. The different types of adhesives that have been study in this report is epoxy adhesive, epoxy-hybrid cyanoacrylate adhesive, hot melt by polyamide and two types of silicon glue. They have been glued to some of the different plastics that the cables are made of in the truck and then they have been exposed to tensile tests, chemical tests, aging and climate tests. None of the tested adhesives passed all the tests, but silicon glue passed most of the tests.

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