Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 45 for “"chemical degradation"”.
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Vibrating CPD Chemical Degradation Oil Sensor
… during research and development. The lubricants chemical, physical, or lubricating properties are validated for quality control purposes and product performance classification. Much of the research in this area is devoted to the online oil degradation systems which allow getting a prompt response …
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Long-term thermal/chemical degradation of ceramic candle filter materials
… from granular SiC. The SiC filters show binder degradation in steam as well as in alkali-containing environments at temperatures as low as 700°C, with oxidation of the SiC occurring in the steam environments at higher temperatures. Sodium and potassium contaminants in the steam atmospheres …
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Microbial and Chemical Degradation of Atrazine: Two Possible Herbicide Disposal Methods
Made available in DSpace on 2014-12-14T14:37:29Z (GMT). No. of bitstreams: 1 8009028.pdf: 1823983 bytes, checksum: f387edeed9d5783aa06813776a91062b (MD5) Previous issue date: 1979
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Morphological and Mechanical Properties of Dispersion-Cast and Extruded Nafion Membranes Subjected to Thermal and Chemical Treatments
… Nafion® subjected to an ex-situ, Fenton's chemical degradation test. Nafion®, a perfluorosulfonate ionomer, is considered a commercially successful semi-crystalline ionomer with primary applications in chlor-alkali cells and proton exchange membrane fuel cells. With the aid of dynamic …
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Mechanistic studies on chemical instabilities of recombinant proteins
… due to the existence of various physical and chemical degradation pathways. Degraded protein molecules have much reduced biological functions, and may also have adverse effects such as immunogenriicity or pharmacokinetic issues. Thus, understanding the underlying mechanisms of these …
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A stochastic model of component failure mechanisms
The progress of a unimolecular chemical degradation reaction is used in representing a component failure mechanism. The component is said to fail when the concentration of reaction product accumulates beyond an acceptable level. The process of accumulating reaction product is modelled as a Markov …
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High Resolution Mass Spectrometric Approaches To Study Protein Structure and Environment in Lyophilized Solids
… ions can promote instability that manifests as chemical degradation (e.g. oxidation, deamidation, hydrolysis) and/or physical degradation (aggregation, phase separation). Since several degradation pathways are accelerated by diffusion in solution, proteins are lyophilized to improve stability. …
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ACID-BASE REACTIONS IN DIFFERENT SOLID-STATE FORMS
… would induce deleterious form conversions or chemical degradation of the APIs during storage or manufacturing. Therefore, understanding the fundamentals of acid-base reactions is critical to design a robust formulation and to avoid drug-excipients incompatibility issues in multicomponent …
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Spectrophotometric and microbiological determination of the stability of sodium ampicillin as affected by pH
… a pH profile may be established to predict chemical stability with ampicillin sodium alone or when other drugs may be included in the admixture. With a pH profile the pharmacist could predict the length of time after which more than a 10 percent loss of activity would occur. Stability …
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The effect of environmental aging/exposure on the durability of high performance polymeric composites
… been known to undergo both physical as well as chemical aging. The aging time, temperature, and environment play a significant role in affecting the physical and chemical aging behavior in the polymers. Currently, there is a dearth of information on the combined effects of physical and chemical …
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Preparation and Characterization Of Oil-in-water Nano-emulsions Of Trifluoperazine For Parenteral Drug Delivery
… degraded. Drug content analysis showed chemical degradation due to reduction of potency. </p><p> Conclusions: Trifluoperazine nano-emulsions formulations had acceptable values of low z-average, low polydispersity index and high zeta potential and were physically stable but not chemically …
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Performance of aerogel composite and foam insulations
… were observed to have various levels of degradation of thermal properties, losing about 5% of resistivity during the most extreme environmental conditions. Degradation in the aerogel com- posites was found to be caused by one or multiple of the following: infusion of humid air into the …
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Asymmetric synthesis of novel anthracyclinones
… analysis, nuclear Overhauser enhancements and chemical degradation. Attempts were made to extend the highly selective acetal cyclisation methodology to the intramolecular reaction of the allylsilane (121), cyclisation of which was expected to provide enantioselective access to the alkene (146). …
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The elastic properties of calcium leached cement pastes and mortars : a multi-scale investigation
… macroscopic mechanical properties. Although the degradation of strength has been elaborately studied in the last decade, the degradation of elasticity has not been investigated in the same depth. This thesis presents a combined experimental-theoretical investigation of the loss of elastic modulus …
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DEGRADATION OF PROTECTIVE GLOVE MATERIALS EXPOSED TO COMMERCIAL PRODUCTS: A COMPARATIVE STUDY OF TENSILE STRENGTH AND GRAVIMETRIC ANALYSES
… which type of glove is appropriate for handling chemicals; however, they include information on less than 1% of the 89 million chemical products available today.</p> <p>This study offers a solution by testing five durable polymer materials against 50 chemicals, using two rapid chemical …
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Mechanics of abrasive wear of elastomeric materials
… loading conditions, thermal conditions, and chemical degradation of materials. Much research has been conducted in the past. However, direct observations of the wear process are rare. The mechanics underlying the abrasive wear of elastomeric materials is unclear. In order to provide …
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Measuring Material Properties of Proton Exchange Membranes using Pressure Loaded Blister Testing and Digital Image Correlation
… to the internal combustion engines they replace. Chemical degradation was once viewed as the most common culprit of early fuel cell failure, but as membranes and catalysts improved, mechanical failure became an important factor. As a result, fundamental research on the mechanically-induced failure …
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Long term degradation of resin for high temperature composites
… harsh environments is a major concern. Surface degradation and damage are observed in polyimide composites used in air at 125-300°C. It is believed that diffusion of oxygen into the material and oxidative chemical reactions in the matrix are responsible. Previous work has characterized and …
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The development of novel services for battery storage in domestic applications and communal mini-smart grids
… gradual internal resistance growth due to electrochemical reactions leading to structural and chemical degradation. This study focuses on the utilisation of the Lithium-ion battery within residential applications and relevance in facilitating the decarbonisation of the UK’s energy generation and …
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Design and synthesis of new materials for the protection, restoration, and conservation of carbonate stone artifacts of interest in the field of Cultural Heritage.
… due to their susceptibility to weathering and chemical degradation. This PhD research focuses on developing innovative inorganic treatments to improve the durability of calcareous substrates by forming insoluble and chemically compatible protective phases. Among the most studied consolidants, …
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