Dissertations / Theses: 'Quality materials'

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Postelnicu, Eveline. "Assessing materials quality for high efficiency electricity generation." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111327.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 54-55).
Thermalization losses drastically reduce the efficiency of silicon solar cells. In an age where we need sustainable energy production more than ever, silicon is the best material to target due to its high stake in the sustainable energy market. An organic-inorganic solar cell hybrid of tetracene-covered silicon can reduce thermalization losses through the downconversion process of using a high energy photon to generate two lower energy electron-hole pairs. This occurs through the singlet-triplet fission process that excitons can undertake in tetracene. The effect of the interface quality between tetracene and silicon on successful triplet energy transfer is investigated. RFPCD (Radio Frequency Photoconductive Decay) is used to measure the bulk lifetime as well as the surface recombination lifetime of minority carriers in both n- and p-type Silicon of various doping concentrations. The surface recombination velocity was calculated from the measurement of surface recombination lifetime and analyzed after the silicon underwent RCA clean, RCA clean followed by an HF dip, tungsten nitride ALD, and tetracene evaporation using various combinations of these steps to form appropriate process flows. It was found that the highest surface quality was obtained by the lowest doped wafers. Additionally, similar doping levels were affected similarly by the various processing steps outlined above while the type of dopant did not seem to dictate the surface quality response. Triplet energy transfer was not fully confirmed from tetracene to silicon, but the surface quality turned out to be a very important indication for whether or not this energy transfer could occur.
by Eveline Postelnicu.
S.B.

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Horkeby, Filip, and Melanie Larsson. "Quality Assurance of Pressure Equipment Materials and Steelwork." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-127336.

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Kvalitetskraven i samhället blir allt högre och det blir allt tuffare för producenterna att hålla de kvalitetskrav som krävs av kund, men också att uppnå de kvalitetsdirektiv som finns i EU idag. Det finns idag en mängd olika definitioner på vad kvalitet är och hur kvaliteten ska uppnås. EU kräver att alla produkter ska ha CE-märkning, vilket är en försäkring om att produkterna håller den kvalitet som definierad av EUs lagstiftning. För att möta de krav som finns på kvalitet idag undersöker Siemens Industrial Turbomachinery AB om deras leverantörer följer de direktiv som krävs för tryckbärande anordningar. För att materialen i de tryckbärande anordningarna ska vara godkända krävs det att ståltillverkaren är godkänd för tillverkningen. Ståltillverkaren ska kunna bekräfta godkännandet genom att uppvisa ett så kallat PED certifikat (Pressure Equipment Directive, 97/23/EC).

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Quitoriano, Nathaniel Joseph. "High-quality InP on GaAs." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37370.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.
Includes bibliographical references (leaves 173-181).
In addition to traditional telecommunication applications, devices based on InP have received increased attention for high-performance electronics. InP growth on GaAs is motivated by the fact that InP wafers are smaller, more expensive, and utilize older fabrication equipment than GaAs. High-quality InP on GaAs may also serve as a step towards bringing high-quality InP onto the Si platform. Integrating high-quality InP onto bulk GaAs has proven to be challenging, however. While a number of commercial Molecular Beam Epitaxy (MBE) growth foundries offer InP on GaAs for M-HEMT (Metamorphic High-Electron-Mobility Transistor) applications, the successful demonstration of InP-based, minority-carrier devices on bulk GaAs remains elusive. In this work InP on GaAs suitable for minority carrier devices is demonstrated exhibiting a threading dislocation density of 1.2x1 06/cm2 determined by plan-view transmission electron microscopy. To further quantify the quality of this InP on GaAs, a photoluminescence (PL) structure was grown to compare the quality to bulk InP. Comparable room and low (20K) temperature PL was attained. (The intensity from the PL structure grown on the InP on GaAs was -70% of that on bulk InP at both temperatures.)
(cont.) To achieve this, graded buffers in the InGaAs, InGaP, InAlAs and InGaAlAs materials systems were explored. In each of these systems, under certain growth conditions, microscopic compositional inhomogeneities along the growth direction blocked dislocations leading to dislocation densities sometimes > 109/cm2. Using scanning-transmission electron microscopy, composition variations were observed. These composition variations are caused by surface-driven phase separation leading to Ga-rich regions. As the phase separation blocked dislocation glide and led to high threading dislocation densities, conditions for avoiding phase separation were explored and identified. Composition variations could be prevented in InxGal-,As graded buffers grown at 725 °C to yield low dislocation densities of 9x105/cm2 for x < 0.34, accommodating -70% of the lattice mismatch between GaAs and InP. However, further grading to 53% In is required to attain the lattice constant of InP. Compositional grading in the InyGal_yP (0.8 < y < 1.0) materials system was found to accommodate the remaining lattice mismatch with no rise in threading dislocation density by avoiding phase separation.
(cont.) Consequently, to achieve high-quality InP on GaAs a graded buffer in the InGaAs material system was followed by a graded buffer in the InGaP materials system to reach InP. The research to achieve high-quality InP on GaAs diverged into two paths. The first successful path, using graded buffers in different materials systems, was discussed above. The second path involved the deposition of InP at various temperatures on the high-quality Ino.34Gao.66As platform that was developed to determine if InP deposited on the InGaAs platform with 1.2% misfit relaxed controllably without much dislocation nucleation. To the contrary, rampant dislocation nucleation occurred in this highly-strained InP at all temperatures studied. Interestingly, however, the InP was observed to relax via a secondary-slip system, a/2<110>{1 10}. This secondary-slip system has a Burgers vector typical in semiconductors of a/2. Unlike the primary-slip system, where dislocations glide on { 111 }-type planes, the secondary-slip system dislocations glide on { 110}-type planes. Relaxation via the secondary-slip system was found to be a function of stress and temperature.
(cont.) A critical stress, ec, appears to be required for dislocations to glide via the secondary-slip system otherwise all relaxation occurs by the primary-slip system. For e > ec and at all temperatures studied, both the primary- and secondary-slip systems are active with apparent cross-slip from one system to the other. At low temperatures, nearly all of the relaxation was accomplished through the secondary-slip system, however. The amount of relaxation via the primary- and secondary-slip systems at three different temperatures was quantified; the resulting Arrhenius plot suggests a difference in the activation energy for glide between the two systems is 1.5 eV.
by Nathaniel Joseph Quitoriano.
Ph.D.

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Brice, Jeremy. "Pursuing quality wine in South Australia : materials, markets, valuations." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:f8ef1e0d-587e-4985-a088-9a1abdc24379.

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This thesis presents an ethnography of the processes and practices through which Australian grape and wine producers attempt to produce, and to assess, quality and value in the materials with which they work. Drawing on participant observation research conducted within two wine companies in South Australia – one owned by a multinational beverage conglomerate, one a family-owned boutique winery – this thesis engages with three overarching questions, which engage with the concerns of agro-food studies and of social studies of markets. First, how – and with what economic effects – are the sensory qualities of materials made to matter within the Australian wine industry? Second, how do grape and wine producers pursue wine quality in a more-than-human world, and in what ways might their endeavours problematise extant theorisations of economic agency? Finally, what might be the consequences of Australian wine producers’ recent engagements with principles of grape and wine quality centred upon geographical origin? In response to these questions, this thesis explores time-reckoning and value production in viticultural practice, the pricing of winegrapes during a fungal disease epidemic, the commercial relationships convened through the production of large-volume mass-market wine blends, and Australian wine producers’ recent attempts to produce ‘wines from somewhere.’ These empirical engagements lead it to argue that the qualification and valuation practices deployed within the Australian wine industry do not simply affect the qualities and prices of grapes and wines. They also shape economic agencies and vulnerabilities, organise and value commercial relationships among grape growers and wine producers, and reassemble the economic geographies of Australian grape production. This thesis concludes that because different ways of pursuing quality enact these phenomena in different ways, much may depend not only upon how successfully, but also upon how – through what techniques, practices, and associations – quality is pursued.

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Ramos, Irene. "Quality perception study in sustainable materials for Volvo Cars." Thesis, Jönköping University, JTH, Industridesign, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-53172.

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The growing demand in the industry towards sustainability and the globalization of manufacturing lead to an industrial climate of constant development and improvements, and automotive interior design is not excluded. In 2017 the European Union declared that the material used to generate the bright chrome surfaces of car interiors (CR VI) is toxic and carcinogenic. This implies that Volvo will ban the use of Chrome VI for decorative parts from September 2024. Finding a more eco-friendly alternative to replace CR VI not only functionally but also in terms of perceived quality and user experience will be an urgent and decisive action. In this project, the parameters of gloss, haze, color temperature, and metallic depth are investigated in order to figure out which elements ensure the perceived quality of chrome surfaces. For this purpose, a user study based on different sensory tests and soft metrology was carried out with 48 people, as well as seven samples, five of them more eco-friendly alternatives. This project aims to introduce a set of tools to assess and guarantee the perception of quality by supporting the development of "chrome-look" surfaces in the automotive interior with new sustainable materials. Through this study, correlating soft and hard metrology, it is observed what makes a surface perceived as "high-quality" and which of the more eco-friendly alternatives could be the most optimal to replace Chrome VI in Volvo's car interiors.

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Newton, Claudia. "Towards sustainable luxury materials selection : measuring the perceived quality of automotive interior materials : innovation report." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/109972/.

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Automotive companies are searching for new, innovative materials that attempt to redefine what is traditionally associated as a ‘luxury material’. Market research shows that future customers will demand tangible sustainability in vehicle interiors through the use of eco-friendly materials. However, research has also identified customer scepticism towards the quality of green products sold by luxury brands. The perception of quality is typically determined by peripheral and sensorial product properties such as styling, shape and touch. The uncertainty of new materials compounded by the need to balance sustainability, sensory and emotional appeal mean it is no longer possible to rely on the designers’ intuition and experience to evaluate materials. Rigorous, robust methods which include both objective material assessments and the quantification of subjective, sensory and experiential attributes will maximize the chance of successful adoption by customers. They can also offer further insight, such as demonstrating that the Perceived Quality (PQ) of a cheaper material can be improved just by making the material softer using a foam backing, as was found in this research. To address this, a new process has been developed to measure the perceived haptic quality of soft automotive interior materials. Studies were conducted in the UK and Hong Kong to generate user-defined metrics. Of these metrics, roughness and hardness had the largest impact on PQ, so mechanical testing was conducted to obtain objective measurements of both. The subjective and objective measurements were found to correlate strongly, implying that objective measurements alone could indicate a customer’s opinion of these materials. The final stage of the process introduces a statistical model which uses the objective data to predict PQ scores. This is based around an Artificial Neural Network validated as accurate to within 4.5%. A graphical user interface was designed so practitioners can use the model to predict how customers may respond to a new material or a change in the surface characteristics of an existing material, without needing to conduct the initial customer research. The process has been integrated in part within the sponsor company and has influenced future research and business strategy in this area.

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Kenerson, Jonathan E. "Quality Assurance and Quality Control Methods for Resin Infusion." Fogler Library, University of Maine, 2010. http://www.library.umaine.edu/theses/pdf/KenersonJE2010.pdf.

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Cerrato, Jose Manuel. "Impact of Piping Materials on Water Quality in Tegucigalpa, Honduras." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35030.

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The possible effects of pipe materials on drinking water quality have been analyzed in the distribution system of the water treatment plant of "La La ConcepciÃ³nâ " in Tegucigalpa, Honduras. "La La ConcepciÃ³nâ " is a surface water reservoir experiencing biogeochemical cycling of manganese. Black water problems have been reported in the distribution system since 1998. An evaluation of the potential influence that PVC and iron pipes could have on the concentration of iron and manganese in drinking water, the effects caused by the presence of manganese in PVC and iron pipe surfaces, and residual chlorine and Pb concentrations in the distribution system was performed. The sampled neighborhoods received an intermittent service. Water was suspended for 8 hours every day due to water quantity problems in the city. Water and pipe samples were obtained for PVC and galvanized iron pipes because these constitute the majority of the infrastructure used for distribution systems in Honduras. Thermodynamic and kinetic conditions for possible manganese oxidation by chlorine and dissolved oxygen in the distribution system were also evaluated. As expected, total Fe concentrations were greater for first flush conditions from the iron pipe. Water samples obtained from the PVC pipe showed higher total Mn concentrations and more black color than those obtained from the iron pipe for both first flush and continuous flow conditions. Residual chlorine decayed relatively fast along the sampled section of the distribution system. Pb concentrations were detected on water samples obtained from PVC for first flush and continuous flow and on iron pipe for first flush. Preliminary experiments showed that manganese-oxidizing and -reducing bacteria were present in the walls of both PVC and iron pipes. Higher numbers of colony-forming microorganisms were recovered from iron (30-fold more) compared to PVC pipe sections. However, the majority of isolates from the PVC biofilm (8 of 10, 80 %) were capable of Mn-oxidation while only 35 % (11 of 31) of isolates from the iron biofilm sample demonstrated Mn-oxidation. This research demonstrates the importance of the different interactions between water and the infrastructure used for its supply in producing safe drinking water.
Master of Science

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Gallagher, James C. "Synthesis and Investigation of High Quality Materials for Spintronics Applications." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469141590.

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Cooper, Mark J. "Evaluation of the quality and promotion of open learning materials." Thesis, Aston University, 1992. http://publications.aston.ac.uk/11930/.

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In the UK, Open Learning has been used in industrial training for at least the last decade. Trainers and Open Learning practitioners have been concerned about the quality of the products and services being delivered. The argument put forward in this thesis is that there is ambiguity amongst industrialists over the meanings of `Open Learning' and `Quality in Open Learning'. For clarity, a new definition of Open Learning is proposed which challenges the traditional learner-centred approach favoured by educationalists. It introduces the concept that there are benefits afforded to the trainer/employer/teacher as well as to the learner. This enables a focussed view of what quality in Open Learning really means. Having discussed these issues, a new quantitative method of evaluating Open Learning is proposed. This is based upon an assessment of the degree of compliance with which products meet Parts 1 & 2 of the Open Learning Code of Practice. The vehicle for these research studies has been a commercial contract commissioned by the Training Agency for the Engineering Industry Training Board (EITB) to examine the quality of Open Learning products supplied to the engineering industry. A major part of this research has been the application of the evaluation technique to a range of 67 Open Learning products (in eight subject areas). The findings were that good quality products can be found right across the price range - so can average and poor quality ones. The study also shows quite convincingly that there are good quality products to be found at less than 50. Finally the majority (24 out of 34) of the good quality products were text based.

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Sears, Forest (Forest Orion). "3D print quality in the context of PLA color." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104320.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 45).
3D printing is a hot topic in manufacturing and a truly useful tool, but it has limitations. Print quality properties - like raft peelability, dimensional tolerance and surface roughness - are hard to calibrate perfectly. A common material used in fused deposition modeling (FDM) printers is polylactic acid (PLA). One print quality concern is how different colors of PLA print differently under the exact same settings. The inconsistency in print quality by color is bad for designers, students, and engineers who want to rapidly prototype effectively. Analyzing the thermal, chemical and mechanical properties of the different colors of PLA and relating it to the quality of the prints gives the user a chance to calibrate their machine effectively for higher quality prints. The quality of prints are quantified by scoring systems that measure three properties of a print: dimensional tolerance, how easily the raft peels from the print, and the surface roughness. The thermal properties of the different colors of PLA were analyzed using differential scanning calorimetry (DSC) up to 230° C. The integrals of peaks and troughs from the DSC - representing heat absorbed and released by the different colors of PLA - show that each color responds differently to thermal treatment. The mechanical strength of each color was found to be different through uniaxial tensile testing. Yellow and orange filament had high percent crystallinity at -12.1%, while having a high yield stress at 41-45 MPa, and a low yield strain at 6.6%-11% extension. Red and blue filament had low percent crystallinity at ~8.8-10.2%, while having a low yield stress at 33-36 MPa, and a high yield strain at 18%-23% extension. Additionally, Fourier transform infrared spectroscopy (FTIR) analysis determined each PLA color had unique additives. For calibrating printers for reliably high quality prints, crystallinity has a relationship with the amount of material extruded which could factor into qualities like dimensional tolerance and surface finish.
by Forest Sears.
S.B.

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Miedl, Michaela. "The effect of raw materials and yeast quality on beer stability." Thesis, Heriot-Watt University, 2010. http://hdl.handle.net/10399/2620.

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Beer stability is a critical quality parameter and a large amount of research has attempted to understand and optimise it. The present study focused on the flavour and foam aspects of beer stability and novel methods of analysis were employed to investigate the influence of yeast physiological state, pitching rates, pasteurisation methods and raw materials on these important parameters. Laser scanning confocal microscopy and flow cytometry were used to gain an in-depth understanding of physiological state and protein dynamics of brewing yeast. Yeast cell components such as glycogen, neutral lipids, trehalose, bud scars, DNA and intracellular proteinases were successfully visualised and quantified. Co-localisation studies with a yeast GFP clone expressing proteinase A (Pr A) were conducted to explore expression and excretion of Pr A in a variety of stress situations encountered during wort fermentations. Pr A plays a key role in the degradation of the hydrophobic polypeptides responsible for the beer foam stability. The impact of flash pasteurisation compared to sterile filtration on Pr A levels, hydrophobic polypeptide content and foam stability has been investigated. Another focus of this study was to elucidate the origin and fate of polypeptides, throughout wort production and fermentation. Special emphasis was placed on the changes in size and/or hydrophobicity of foam active polypeptides throughout the brewing process in order to identify stages in the process where retention of foam active polypeptides and consequently beer foam stability could be increased. It was attempted to determine what proportion of polypeptides found in beer originate from the cereals and the hops and how these polypeptides evolve throughout the brewing process. High and lower gravity beers were compared with regard to their polypeptide distribution and degree of polypeptide glycosylation. Understanding the mechanisms of beer staling is a longstanding research priority of brewers in order to extend beer shelf life. It was attempted to shed light on the mechanisms involved in beer staling, the role of Reactive Oxygen Species and their interaction with thiol groups in beer proteins. Several approaches for inhibiting or retarding oxidation of the beer matrix were explored. Novel methods for the assessment of oxidative stability and content of thiol and carbonyl groups in beer proteins were developed.

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Herzberg, Tina Sue. "The quality of brailled instructional materials produced in Texas public schools." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1789.

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Heim, Timothy Howard. "Impact of Polymeric Plumbing Materials on Drinking Water Quality and Aesthetics." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/32260.

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The use of polymer pipes is now very common in home plumbing and other parts of the drinking water distribution system. Many taste and odor complaints in drinking water are known to originate from contact of water with materials. The ability of polymer pipes used in home plumbing to affect drinking water quality and aesthetics was investigated using the Utility Quick Test (UQT). Analysis of water quality and aesthetics were conducted in the absence of disinfectant and the presence of either chlorine or chloramines. A Flavor Profile Analysis (FPA) panel was trained according to Standard Methods 2170B to evaluate the organoleptic characteristics of the samples. Laboratory analyses were performed to determine levels of total organic carbon (TOC), disinfectant residual, pH and to attempt to identify specific volatile organics.

The first part of this study investigated HDPE, cPVC and epoxy lined copper pipes using the UQT method. Both HDPE and epoxy-lined copper had significant effects on water quality and aesthetics during the approximately 10 day exposure of the UQT. HDPE and epoxy-lined copper leached significant amounts of TOC and consumed more disinfectant than controls, but in different amounts. cPVC was the most inert of the materials tested and had the least impact on water quality and did not contribute any significant odor. None of the pipes tested appeared to contribute trihalomethanes to drinking water, but further analysis revealed that the compounds may actually be generated and subsequently sorbed into pipe walls. These data show the effects of newly installed polymeric pipe materials and their potential to impact water quality in differing capacities.

The second part of this study compared the results of the UQT on HDPE, epoxy lined copper, cPVC, PEX-a and PEX-b with the goal of comparing and contrasting how five different polymeric plumbing materials can impact drinking water quality. Results demonstrated the short-term ability of all pipe materials except cPVC to impact water quality and aesthetics. This data could potentially be useful in generating selection criteria for homeowners and plumbing professionals regarding the impact of newly installed plumbing materials.

Master of Science

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Sinno, Rami Assem 1964. "Quality assurance for the clinical ferromagnetic seeds project." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276967.

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Surgically implanted thermoregulating ferromagnetic seeds as a mean of inducing hyperthermia in malignant tumors has been successfully introduced in a clinical environment at the University of Arizona. This work covers topics in quality assurance for the method on two levels. The first level deals with the magnetic induction system where magnetic and electric fields are measured. A discussion on safety levels for patients and treatment personnel is given, and an optically coupled probe for magnetic field measurements is described. The second level treats the electrical characteristics of the ferromagnetic seeds. Systems to measure the permeability and conductivity of the seeds are presented with some typical results. Finally, hysteresis power loss in a seed is measured and compared to losses due to eddy currents.

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Zaklouta, Hadi. "Cost of quality tradeoffs in manufacturing process and inspection strategy selection." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76133.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 106-108).
In today's highly competitive markets manufacturers must provide high quality products to survive. Manufacturers can achieve higher levels of quality by changing their manufacturing process and/or by product inspection where a multitude of different strategies are often available. Each option has its own cost implications that must also be taken into account. By reconciling the competing objectives of quality maximization and cost minimization, a cost of quality approach serves as a useful framework for comparing available manufacturing process and inspection alternatives. Still, any rigorous comparison requires both a metric as well as a profound understanding of cost of quality tradeoffs. The cost of quality tradeoffs in manufacturing process and inspection strategy selection are examined through a probabilistic cost of quality model explored analytically using a sample set of fundamental inspection strategies (reinspect rejects, reinspect accepts and single inspection) and applied to the case of electric vehicle battery pack assembly. From an expected value point of view a series of parametric sensitivity analyses reveal that complex tradeoffs between manufacturing process, inspection, internal and external failure costs determine the optimal manufacturing process and inspection strategy combination. In general, reinspect rejects minimizes internal failure costs, reinspect accepts minimizes external failure costs and single inspection lies in between while minimizing inspection costs. This thesis illustrates the fact that results are scenario specific and depend on product cost-, manufacturing process and available inspection method attributes. It is also observed that manufacturing process improvement often coincides with a need to change inspection strategy choice, thereby indicating that manufacturing process and inspection strategy selection should not be performed independently of each other. This thesis demonstrates that the traditional expected value approach for evaluating cost of quality implications of manufacturing and inspection is often misleading. Decision tree formulations and discrete event simulations indicate that cost of quality distributions are asymmetric. High internal- and external failure costs, manufacturing process non-conformance rates and inspection method error rates are contributing factors. The alternative metric of expected utility captures decision makers risk aversion to high cost outliers and changes the criteria for optimality and favors inspection strategies and manufacturing processes that minimize external failure events with increasing risk intolerance. In the examined case of electric vehicle battery pack assembly both material- and external failure costs are very high. Analytical and discrete event simulation results indicate that for the given welding process the inspection strategy that minimizes external failure costs is optimal from an expected cost point of view as well as at high degrees of risk aversion. This result is shown to be sensitive to parameters driving the cost and probability of external failure events.
by Hadi Zaklouta.
S.M.

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Falch, Eva. "Lipids from residual fish raw materials : Quality assessment by advanced analytical methods." Doctoral thesis, Norwegian University of Science and Technology, Department of Biotechnology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2263.

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ADDENDUM Figure 4, page 14; Copyright © 1996 From Food Chemistry by Nawar, W.W. (Fennema, O.R.ed). Reproduced by permission of Routledge/Taylor & Francis Group, LLC Paper I, VII and VIII are reprinted with kind permission from Elsevier, sciencedirect.com

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Gaete-Martinez, Victor. "Optical Measurement of Strang Geometry and Orientation and Their Influence on Oriented Strand Composite Formation Quality." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/theses.asp?highlight=1&Cmd=abstract&ID=FTY2009-004.

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Slagter, Alejandra. "Advanced Inspection of Surface Quality in Continuously Cast Products by Online Monitoring." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70634.

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Maher, Tabitha V. "An air quality study of nanomaterials in a manufacturing setting." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1442102.

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Zhang, Jinsong 1975. "Modeling VOC sorption of building materials and its impact on indoor air quality." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/71107.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2001.
Includes bibliographical references (p. 158-162).
Sorption of volatile organic compounds (VOCs) by building materials can have significant effect on the indoor VOC concentration levels and indoor air quality in buildings. The objective of this study was to investigate experimentally the effects of environmental conditions (temperature, humidity and air velocity) on the sorption rate and capacity of three typical types of building materials (carpet, ceiling tile and painted drywall), and to evaluate existing sorption models with experimental data. A small-scale chamber test system has been developed in this study to conduct sorption tests under different environmental conditions. The sorption data collected were analyzed by three different analysis methods: the integration method, the linear Langmuir model method and the diffusion model method. The results of the integration method indicated that for the painted drywall, the differences among different environmental conditions were so small compared with the experimental uncertainties that no statistically significant environmental effect could be observed at 95% confidence level. The sorption of VOCs on ceiling tile decreased with the increase of the air velocity and temperature, but did not change significantly with the relative humidity. The sink strength of benzaldehyde under high humidity was much stronger than any other conditions. The sorption of VOCs on carpet appeared to be a diffusion-controlled process. With the increase of temperature, the diffusion coefficient increased while the partition coefficient decreased. A higher air velocity increased the sink capacity of dodecane on carpet. The relative humidity had no significant effect on the sorption of VOCs on carpet. Based on the model evaluation conducted in this study, the linear Langmuir model appeared to be suitable for painted drywall and ceiling tile while the diffusion model is more suitable for carpet.
by Jinsong Zhang.
S.M.

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Grönlund, Ulla. "Quality improvements in forest products industry : classification of biological materials with inherent variations." Doctoral thesis, Luleå, 1995. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16899.

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Classifying logs and boards has an essential economic impact on the forest products industry. In contrast to other process industries the sawmills do not try to homogenize the raw material, but instead try to utilize the inherent properties of every single log and board in the best way. The aim of this thesis is to improve the quality control and decrease the costs for poor quality by introducing new methods to measure and describe the raw material. The work is focused on the grading procedures, and thereby 1) analyzing the relevance of the current classification systems and investigating the characteristics that are the most important ones in today´s grading procedures; 2) evaluating models developed to detect interior defects in logs automatically, giving suggestions for improvements; 3) suggesting ideas and methods for a classification system for tomorrow. The investigation comprises partly about 1100 Scots pine (Pinus silvetris) logs harvested on 16 randomly selected stands in Sweden and graded both by graders and by an automatic equipment; partly around 600 pine logs from permanent sample plots in Sweden and scanned by a CT-scanner (Computed tomography). The predictability between the grade of a log and its boards is very low, around 20%. Repeated investigations show that two graders assess the same grade on about 50% of the logs and boards, i.e., they judge the properties equally. The results also emphasize that the current manual classification systems are not in concordance with the customer´s demand and the natural variations in the material cannot be handled in an efficient way by current grading rules and transformed by human beings. The CT-scanner is used to measure the interior properties (defects) of a log. The validation of the methods and models shows that when the accuracy is improved for small knots, the models identify a knot with an accuray of +/- 5 mm. An embryo to a property index, PI, that gives an individual description of the inherent properties of logs and boards, is given. Based on customer-orientation and various strategies for describing log properties, a clustering procedure can be evaluated in order to form and describe appropriate classes (clusters, grades). Then, by an allocation rule with the function for assessing a grade, every single log or board can be automatically classified into one group.
Godkänd; 1995; 20070428 (ysko)

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Freemantle, Richard James. "Ultrasonic compression wave evaluation of adhered metal sheets and thin sheet materials." Thesis, Keele University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282635.

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Samavedam, Srikanth B. (Srikanth Balaji) 1970. "Growth and characterization of high quality relaxed graded silicon germanium layers for integrated photodetectors." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9586.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.
Includes bibliographical references (leaves 137-147).
Silicon germanium layers on silicon substrates (SiGe/Si) are useful for a variety of microelectronics applications. The most successful technique for growing low defect density relaxed SiGe/Si layers is relaxed compositional grading. However, with increasing Ge content in the graded SiGe layers, the following materials concerns need to be addressed-{i) a high surface roughness, (ii) the formation of dislocation pile-ups, (iii) an increase in the threading dislocation density, (iv) tensile strains and micro-cracking due to thermal mismatch, and (v) particulate contamination from germane gas phase nucleation. We have grown relaxed graded SiGe/Si layers using ultra-high vacuum chemical vapor deposition (UHVCVD) at growth temperatures ranging between 500°-900° C and pressures between 30-500 millitorr. The SiGe growth rates at different temperature and Ge content regimes agree with previously proposed theories. By applying both a dislocation blocking criterion and surface roughness effects to graded SiGe/Si structures, we have proposed a model to explain and predict the formation of dislocation pile-ups in graded structures. We have discovered that there is a substantial improvement in the surface roughness and dislocation pile-up density in graded SiGe layers by growing on miscut Si(00l) substrates. It was found that the array of 60° dislocations that usually forms to relieve the misfit stress could transform into a novel lower energy hexagonal dislocation network consisting of all edge dislocations. High resolution X-ray diffraction measurements indicate that there is a decrease in the rate of epilayer tilting in the Ge-rich layers of the graded buffer in agreement with the observed dislocation structure. We have designed an optimized relaxed buffer (ORB) process that allows us to grow high quality Ge layers on Si substrates. By employing a chemical mechanical polishing (CMP) and regrowth step within the epitaxial structure, we have minimized the formation of dislocation pile-ups. Compressive strain has been incorporated into the graded layers to overcome the thermal mismatch problem. The ORB process eliminates dislocation pile-ups, decreases gas-phase nucleation of particles, and eliminates the increase in threading dislocation density. Germanium p-n photodiodes were fabricated to assess the diectronic quality and prove the feasibility of a high quality infrared detector on a Si substrate. The dark current in the diodes was at least two orders of magnitude lower than any previously reported value for Ge photodiodes on Si substrates. Capacitance measurements indicate that the devices are capable of high speed operation. Dislocation filtering experiments were conducted to reduce threading dislocation densities on pattered mesas. It was found that at the strain levels from small compressive mismatch, dislocation nucleation from the mesa edges dominates over dislocation filtering.
by Srikanth B. Samavedam.
Ph.D.

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Azari, Dorcheh Kamran. "Investigation of the materials and paste relationships to improve forming process and anode quality." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/30365/30365.pdf.

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Des anodes de haute densité et de qualité uniforme sont d'un grand intérêt dans la production d'aluminium primaire. La variation dans les propriétés des matières premières ainsi que le grand nombre de variables est reconnue comme étant un grand défi et conduit à des anodes de qualité très variable. Dans ce projet, une d'essai de comportement au compactage de la pâte d’anode a été développée. Le comportement au compactage de la pâte d'anode a été utilisé comme indice de qualité intermédiaire pour réduire le nombre de variables. Différentes combinaisons de temps et de températures de mélange ont été utilisées pour faire de la pâte d’anode afin de comprendre les effets des variables de mélange. Les pâtes ont été compactées, cuites et caractérisés par la suite. Le mélange effectué à 178 C pendant 10 minutes a été celui permettant d’obtenir la distribution la plus homogène de coke et de brai et la densité maximale des échantillons verts et cuits. Il est admis que le comportement à la déformation de la matrice liante (particules fines de coke+brai) contribue fortement au processus de compactage. Les mélanges des matrices liantes et des pâtes d’anodes, avec différents ratios de brai et de particules de coke, ont été compactés à des taux de déformation différentes. La compaction de la matrice liante et de la pâte d'anode, avec les compositions classiques utilisées dans ce projet, n’est pas significativement dépendante de la vitesse de mise en forme. L'effet de la forme et de la densité des particules sur la densité de la pâte compactée a été étudié. La densité apparente des particules, la densité apparente (Scott) et la densité apparente vibrée du lit de particules ont été mesurées pour différentes fractions de cinq sources de coke éponge. Des pâtes d’anode ont été produites à partir des cinq cokes et ensuite compactées. Il a été suggéré que la densité apparente vibrée n'est pas un facteur suffisant pour déterminer les propriétés de compaction et la densité de la pâte compactée et aussi que les facteurs de forme et la densité des particules sont des paramètres importants qui devraient être considérés.

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Kerr, Amanda. "Evaluation and analysis of quality of life picture test materials for persons with dementia." Connect to resource, 2009. http://hdl.handle.net/1811/37274.

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Ghasemzadeh-Barvarz, Massoud. "Quality control of complex polymer materials using hyperspectral imaging associated with multivariate statistical analysis." Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26025.

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Dans la première étape de ce travail, des composites formulés à partir d'anhydride maléique greffé polyéthylène (MAPE) et de différentes charges de fibres de chanvre (entre 0 et 60%) ont été produits et analysés par imagerie NIR. Trois méthodes chimiométriques ont été utilisées puis comparées pour la prédiction des propriétés mécaniques, cartographier la distribution des constituants et détecter les défauts physiques des matériaux: la calibration multivariée traditionnelle basée sur la régression PLS, la résolution multivariée de courbes (MCR) et l’analyse d’images et la régression sur les images multivariées (MIA/MIR). Dans la deuxième partie de ce projet, une série de films multicouches complexes (échantillons industriels) ont été étudiés par imagerie NIR combinée à l’analyse d’images multivariée. Le potentiel et l'efficacité de la méthode proposée pour détecter les défauts causés par la (les) couche(s) manquant(es) ont été étudiés pour des films non imprimés et imprimés. Dans la dernière partie, les composites hybrides polypropylène (PP) / fibre de verre / fibre de lin ont été étudiés. L'effet de la teneur en fibres (0 à 40% en volume) et de la composition sur les propriétés mécaniques ont été investigués, ainsi que l’effet de l’exposition à l’eau et la dégradation thermique et aux rayons UV (vieillissement accéléré des matériaux). Les images de microscopie électronique à balayage (MEB) des composites non vieillis ont été analysées en combinant des méthodes d’analyse de texture et des méthodes multivariées. Enfin, l'imagerie NIR a été mise en œuvre sur des composites non vieillis et vieillis afin de prédire leurs propriétés finales ainsi que pour modéliser les variations de composition chimique et celles dues au vieillissement accéléré. En résumé, les résultats montrent que la combinaison de l'imagerie hyperspectrale et des méthodes statistiques multivariées est un outil puissant pour le contrôle de la qualité des composites polymères complexes. De plus, la méthode proposée est rapide et non destructive, elle peut être mise en œuvre en ligne, pour le contrôle de la qualité des matériaux composites. D'autre part, il a été démontré que l'analyse de la texture des images peut être appliquée à la quantification de la dispersion et du degré d’homogénéité de la distribution des charges dans des matériaux composites.
In the first step of this work, maleic anhydride grafted polyethylene (MAPE)/hemp fiber composites with different filler concentration between 0 to 60% were analyzed by NIR imaging. Three chemometrics methods including Partial Least Squares (PLS), Multivariate Curve Resolution (MCR) and Multivariate Image Analysis/Multivariate Image Regression (MIA/MIR) were implemented and compared for predicting mechanical properties as well as mapping chemical compositions and material physical variations. In the second part of this project, a series of complex multilayer films (industrial samples) were investigated using NIR hyperspectral imaging and Multivariate Image Analysis (MIA). The potential and effectiveness of the proposed method for detecting defects caused by missing layer(s) were studied for unprinted and printed films. In the final part, polypropylene (PP)/glass/flax hybrid composites were studied. The effect of composition (fiber content between 0 and 40 vol%), as well as water, thermal and UV aging on mechanical properties was investigated. Then, Scanning Electron Microscopy (SEM) images of unaged hybrid composites were analyzed using texture analysis and multivariate methods. Finally, NIR imaging was implemented on unaged and aged composites to predict their final properties as well as to capture chemical composition and aging variations. In summary, the results show that combining hyperspectral imaging and multivariate statistical methods is a powerful tool for quality control of complex polymer composites. Since the proposed method is rapid and nondestructive, one can implement it for on-line quality control of finished plastic products. On the other hand, texture analysis and multivariate methods can be applied for quantifying the mixing aspects of composites.

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Elliott, Lewis Roland. "Physical activity in natural environments : importance of environmental quality, landscape type and promotional materials." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/22411.

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Physical inactivity and disconnection from natural environments threatens human health. However, research has demonstrated that natural environments potentially support health-enhancing physical activity which could confer greater physical and mental health benefits than physical activity in other types of environment. This thesis approached the study of physical activity in natural environments through three related pieces of research. Firstly, an experimental study was carried out to explore how the presence of litter in beach environments affected psychophysiological responses to exercise. Responses to exercise did not differ in littered and clean conditions but there was evidence that order effects influenced findings. Visual attention to the two scenes differed, but did not mediate differences in psychophysiological responses. Secondly, analysis of a national dataset was undertaken to explore the form and quantity of physical activity conducted within natural environments in England. A series of linear regressions revealed that higher-intensity physical activities occurred in countryside environments, but more total energy expenditure occurred in coastal environments. Thirdly, a quantitative content analysis of brochures which promote recreational walking in natural environments was conducted which investigated their use of persuasive behavioural messages. These brochures omitted behavioural techniques which may be effective at motivating inactive individuals to walk. Extending this, an online survey tested whether improving brochure content heightened intentions to walk in natural environments. By designing content based on the theory of planned behaviour, the intentions of inactive individuals to undertake walking in natural environments were increased. The findings from this thesis demonstrate that the protection of natural environments is vital for preserving and promoting active recreation and could contribute to population-level increases in physical activity with theory-based promotion in the future.

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Kim, Andrew Y. (Andrew Youngkyu) 1973. "Co-evolution of microstructure and dislocation dynamics in InGaP/GaP : engineering high quality epitaxial transparent substrates." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9031.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2000.
Includes bibliographical references (p. 253-261).
Graded buffers oflnxGa1-xP on GaP ([Delta]x[lnxGa1-x]P/GaP) can be used to fabricate potentially high performance, epitaxial transparent substrates light-emitting diodes (ETSLEDs ). Practical devices have thus far been limited by poor quality: reports of [Delta]x[lnxGa1-x]P/GaP show sharp declines in device and material quality above x - 0.3. This study revisits the challenge of engineering high-quality [Delta]x[lnxGa1-x]P/GaP grown by metal-organic vapor phase epitaxy. A new planar defect microstructure oriented 10-15° off the (1-10), which we call branch defects, was discovered via transmission electron microscopy. Branch defects feature sharp strain fields and dominate the microstructure. causing dislocation pinning and escalation. Branch defects occur later in growth with increasing temperature; however, they are stronger when formed at higher temperatures. Branch defects do not appear to be directly related to other co-existing microstructures in lnxGa1.xP. In the phase space where branch defects are absent, the intrinsic dislocation dynamics of[Delta]x[lnxGa1-x]P/GaP were explored. Dislocation density decreases exponentially with increasing temperature, supporting a kinetic glide model for graded buffers. Dislocation glide velocities also appear to increase dramatically while grading from GaP to InP. Optimizing the co-evolution of dislocation dynamics and branch defects has achieved dislocation densities of [Delta]x106 cm-2 out to x = 0.54, the highest quality [Delta]x[lnxGa1-x]P/GaP reported to date. Reciprocal space mapping reveals three distinct regimes of crystallographic tilt. Qualitative to semi-quantitative models were developed for each regime to elucidate the changing dislocation dynamics during V x[lnxGai-x]P/GaP growth. Critical reanalysis of earlier reports provides further evidence for the kinetic glide model. Overall, discovery of tilt regimes demonstrates the need for a dynamic approach to tilt analysis. A series of ETS-LEDs with emission wavelengths ranging from 575 to 655 nm was fabricated from optimized [Delta]x[lnxGa1-x]P/GaP and shows continuing good performance for [Delta]x 0.3, in contrast to earlier reports. A second, subtle process optimization to better suppress branch defects increases efficiency 60% and drops spectral width 8 meV. Since self-absorption in [Delta]x [lnxGai-x]P/G90%, a fully transparent [Delta]x,y [inx(AlyGa1_y)i-x]P/GaP technology was also developed and initial results promise an order of magnitude improvement in device efficiency. The improvements from subtle process changes suggest a good outlook for achieving practical ETS-LEDs.
by Andrew Y. Kim.
Ph.D.

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Dias, André Luís. "Quality by design e gerenciamento de riscos como estratégias para a construção de um modelo regulatório para medicamentos de base nanotecnológica /." Araraquara, 2017. http://hdl.handle.net/11449/150926.

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Orientador: Maria Palmira Daflon Gremião
Banca: Pedro Canísio Binsfeld
Banca: Marco Vinícius Chaud
Banca: Marlus Chorilli
Banca: Beatriz Stringhetti Ferreira Cury
Resumo: A nanotecnologia tem evoluído rapidamente em diversas áreas, incluindo na área farmacêutica. Para produtos sujeitos à regulação sanitária, em especial medicamentos, esta evolução é um desafio regulatório. Embora já existam medicamentos base nanotecnológica disponíveis no mercado, existem importantes lacunas regulatórias que precisam ser preenchidas. Assim, frente à importância e ao impacto deste tema, foi realizada uma pesquisa científica-regulatória de modo a propor bases para a construção de um arcabouço regulatório, em especial para a regulação de medicamentos de base nanotecnológica. Ficou evidente que não existe, a nível mundial, diretrizes únicas para este tipo de regulação, iniciando pela ausência de consenso no conceito de "nanomaterial". Percebe-se como consenso internacional que a complexidade e diversidade que cerca os nanomateriais exigem abordagens diferenciadas daquelas empregadas em produtos tradicionais, requerendo avaliações caso a caso e abordagens para avaliar os novos riscos introduzidos. Dessa forma, este trabalho avaliou as metodologias Quality by Design (QbD) e Gerenciamento de Riscos como alternativas para a construção do modelo regulatório. QbD e Gerenciamento de Riscos facilitam, compilam, direcionam e sistematizam o conhecimento e assim, por meio do desenvolvimento de produtos robustos, seguindo as etapas previstas no QbD, inclusive com a construção e sedimentação do Perfil de Qualidade Alvo do Produto e de Atributos Críticos a Qualidade, constituem... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Nanotechnology has evolved rapidly in diverse areas, which include the pharmaceutical field. For products subject to sanitary regulation, especially drugs, this evolution is a regulatory challenge. Although there are nanotechnological drugs available in the market, there are important regulatory gaps that must be completed. Thus, in view of the importance and impact of the object, a scientific-regulatory research was carried out in order to propose bases for a regulatory framework, particularly for a regulation of nanotechnological drugs. It became clear that there is no a worldwide guidance for this type of regulation, starting with the lack of consensus for the concept of "nanomaterial". It has been noticed as an international consensus that the complexity and diversity surrounding nanomaterials require different approaches from those used in traditional products, demanding case-by-case evaluation and approaches to assess new introduced risks. Thus, this work evaluated Quality by Design (QbD) and Risk Management methodologies as alternatives for the construction of the regulatory model. QbD and Risk Management facilitate, compile, direct and systematize knowledge and thus, through a robust product development, following as expected by QbD steps - including a construction and sedimentation of the Product Target Quality Profile and Critical Quality Attributes - become important tools for building quality in nanotechnology-based drugs. Risk Management, especially the risk anal... (Complete abstract click electronic access below)
Doutor

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Copeland, Natalie Suzanne. "Evaluating a wood-strand material for wind erosion control and air quality protection." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/n_copeland_113007.pdf.

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Al-Nakeeb, Ahmed A. R. "An assessment of the effectiveness of Quality Assurance Systems in the construction industry." Thesis, University of South Wales, 2000. https://pure.southwales.ac.uk/en/studentthesis/an-assessment-of-the-effectiveness-of-quality-assurance-systems-in-the-construction-industry(bb4ec2f0-37e6-46dc-85e6-3945cfc1da57).html.

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More than two decades have passed since the introduction of Quality Assurance Systems in the form of BS 5750/ISO 9000 yet the effectiveness of these systems are still a matter of controversy and debate. Although the implementation of Quality Assurance Systems in the construction industry has been slow to emerge, most large construction organisations are currently implementing such systems. Much has been written about the advantages and disadvantages of Quality Assurance Systems but unfortunately without any direct reference to any hard data. Most of the reported advantages and disadvantages are based purely on perceptions and views of individuals involved. The British Standards Institution (BSI) acts as a collaborating establishment for this research. This is the first research that attempts to assess the effectiveness of Quality Assurance Systems, in the construction industry. Based on data collected from literature, construction companies and experts in the field of Quality Management, the research provides a better understanding of the objectivity of available data regarding the effectiveness of QA Systems and examines the possibility of fording reliable measures. This thesis shows that no construction company has managed to assess the effectiveness of its Quality Assurance Systems in an objective manner. Regarding measures of the effectiveness of QA Systems, most experts believed that such measures are very important because an organisation must justify the existence of such systems, which are considered as overheads. However, all experts declared 1 that they are not aware of any construction company that has managed to assess the effectiveness of its ISO 9000 in any reliable manner. This research is of a particular value to construction companies who are considering implementing an ISO 9000 as well as those companies that are already implementing such systems.

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Al-khedher, Mohammad Abdelfatah. "Carbon nanotubes characterization and quality analysis using artificial intelligence." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Spring2007/m_al-khedher_041907.pdf.

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Karunaratne, Malintha P. Angelo. "Analysis of alterations in matrix quality at nanoscale in metabolic bone diseases using synchrotron X-ray diffraction." Thesis, Queen Mary, University of London, 2013. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8490.

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Bone diseases such as osteoporosis and rickets cause significant reduction in bone quantity and quality, leading to mechanical abnormalities. While the reduction of bone quantity can be assessed using clinical tools like DXA and pQCT, there is little quantitative knowledge of how altered bone quality in diseased bone increases fracture risk. There is a clear need to develop high-resolution diagnostic techniques to close the gap between onset of fracture relevant changes and diagnosis. Here, a functional imaging technique (in situ synchrotron X-ray imaging with micromechanics) was developed to measure alterations in fibrillar deformation mechanisms in rickets, glucocorticoid-induced osteoporosis (GIOP), and premature ageing. During applied loading, percentage shifts in Bragg peak positions arising from the meridional collagen stagger, measured from the small angle X-ray scattering (SAXS) patterns, give fibrillar level strain as a function of applied stress in real time. To link nanostructural changes to altered fracture risk and deformability, well defined animal (mouse) models created via N-ethylnitrosurea mutagenesis were used. The fibril modulus, maximum fibril strain and fibril-to-tissue strain ratio were determined, complemented by quantitative backscattered scanning electron microscopy and microcomputed tomography to measure microscale mineralisation. A significant reduction of fibril modulus and enhancement of maximum fibril strain was found in rickets and GIOP mice. A significantly larger fibril strain/tissue strain ratio was found in GIOP mice compared to wild-type mice, indicative of a lowered mechanical competence at the bone matrix level. The effects of altered in vivo muscular force distributions on the skeletal system in rickets were measured using position resolved scanning SAXS. Increase of mineral nanoplatelet alignment is observed in wild-type mice near zones of large in-vivo muscle force but not in rachitic mice. These results demonstrate the ability of synchrotron-based in situ X-ray nanomechanical imaging to identify functional alterations in nanoscale bone quality in metabolic bone diseases.

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Durand, Monique Lucia. "Disinfectants and Plumbing Materials: Effects on the Sensory and Chemical Characteristics of Drinking Water." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35861.

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The distribution system is the primary cause of taste and odor complaints in drinking water. This research examined the ability of small diameter pipes used in home plumbing to affect drinking water quality. The properties of the materials were investigated in the absence of disinfectant and the presence of either chlorine or chloramines. A panel was trained in flavor profile analysis (FPA) according to Standard Methods 2170B and used to assess the sensory properties of all samples. Chemical analyses were performed to determine disinfectants, total organic carbon (TOC), pH and specific organic contaminants. The first part of this study investigated PEX pipes manufactured by the silane (PEX-b) and peroxide (PEX-a) cross-linking technology, using the utility quick test (UQT) method. Silane PEX-b had a greater effect on water quality properties such as odor, TOC and residual disinfectant demand than peroxide-linked PEX-a. Chemical analysis revealed that PEX pipes can contribute fuel oxygenates such as ETBE (PEX-b) and possibly MTBE (PEX-a) to drinking water. PEX pipes did not contribute any significant trihalomethanes to drinking water. This study showed that the type of PEX used in homes will determine the extent to which drinking water quality is affected. The second part of this study used simulated plumbing rigs to investigate seven different materials under low flow and stagnant conditions; chlorinated polyvinyl chloride, cross-linked polyethylene, polyethylene, epoxy-lined copper, copper, stainless steel, galvanized iron and glass (control). Results showed that these plumbing materials have the potential to affect water quality characteristics such as TOC concentrations, residual disinfectant and odor when newly installed in homes. A high TOC concentration was consistent with the presence of a distinct odor or a high FPA intensity rating. Galvanized iron produced the worst odors that were consistently described as "motor oil". Polyethylene generated more intense plumbing associated odors than PEX or cPVC plastic material. cPVC and copper generated the least odors. Both copper pipe and epoxy-lined copper consumed residual chlorine and chloramines.
Master of Science

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Simington, Maureen Fresquez 1970. "Redefining manufacturing quality control in the electronics industry." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/34709.

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Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering; in conjunction with the Leaders for Manufacturing Program, Massachusetts Institute of Technology, 2000.
Also available online at the MIT Theses Online homepage .
Includes bibliographical references (p. 103).
The most time consuming and capital intensive portion in the assembly of power electronic devices is the test system. A comprehensive test system including functional and stress screening technologies can significantly increase assembly times and more than double the capital investment required in a new assembly line. The primary purpose of the test system is to screen components for early life failures and to verify proper assembly. Determination of key performance characteristics and the resultant test system are developed during the product design phase and are seldom revised after the product has been released to manufacturing. This thesis explores best practices in testing methods and develops new methods to analyze test system performance. Both efforts were conducted in an effort to optimize existing test regimes. Upon completion of the above analyses the existing test sequence was reduced by 50%. This was primarily due to a discovery in the Burn In test cycle which indicated that failures correlated strongly with the on/off cycles inherent in the test sequence. A new test cycle was proposed to accommodate this finding and test results verified the initial hypothesis. Additionally, the summary of best practices identified new forms of product testing including Highly Accelerated Stress Testing (HAST), moving additional product testing into the development phase consequently reducing testing requirements during assembly.
by Maureen Fresquez Simington.
S.M.

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Eriksson, Conny. "Roll pass design for improved flexibility and quality in wire rod rolling." Doctoral thesis, KTH, Production Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-53.

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The thesis treats roll pass design in wire rod rolling of stainless steel for sequences and series built up by two-symmetrical grooves. It is focused on predicting rolling flexibility, also called working range, as well as product quality. For analysing the flexibility a computer program has been developed. The minimum and maximum roll gap and corresponding bar areas for series of grooves including "oval", "round", "false round", "square" and "diamond" shapes are calculated. Six pass designs used in Swedish mills are analysed. Full-scale rolling is compared with laboratory experiments for the square-oval and false round (round)-oval series. The false round-oval series offers the largest working range and that the flexibility is smaller for pass sequences designed for high reductions. The false round-oval series are also acknowledged as a series for high quality steels and are usually better than the square-oval series having a tendency for defect formation. The thesis also includes high-speed rolling of wire rod in blocks. Here interstand tensions are utilised in order to keep the process stable. For obtaining the required dimensional tolerances of the product they are kept as low as possible. However interstand tensions could be used in order to increase the working range and move the product range towards smaller wire cross sections. For analysing this possibility, a narrow spread technology is utilised. At present time a practical problem is referred to the fixed gearings in the common blocks, which require a certain and given level of interstand tensions and corresponding reductions. This problem can however be solved by means of new block design and modern process control technology. Roll stands can be separately driven and controlled at very high speeds. Thus the eight stand blocks can be subdivided into four plus four passes blocks with a cooling line between enabling also higher productivity without violating the product quality because defect formations caused by a too high rolling temperature. The true working range of a series for a specific steel grade is however not only dependent on the possible spectrum of wire dimensions that can be obtained but might also depend on its ability to decrease or eliminate defects such as surface cracks. Thus, the behaviour of artificial V-shaped cracks in the longitudinal direction has been investigated and compared for the square-oval and false round (round)-oval series mentioned above. In agreement with other research works it was established that efficient rolling conditions for reducing the cracks are obtained when the cracks open up at the same time as their depth is reduced. If the V-shaped crack is closed by contact between its oxidized side surfaces the rolling schedule is not optimal for getting a high quality product. A deeper understanding of the experimental results was obtained by means of an FE-analysis

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Choi, Ki-Seok. "Service level guarantee in capacitated supply chains." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/25583.

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Mampshe, Mashao Frank. "The experiences of senior educators in the quality assurance of head of departments' teaching materials." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/52946.

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Research has shown the importance of the inspiration and experience offered by senior educators in creating successful schools and enhancing the effective and efficient management of the teaching materials used in the school. Due to the diversity and complexity of school management, theorists, policymakers and practitioners acknowledge the crucial role of senior educators values and their influence on the management of schools and the communities. According to Murphy (2002:176) suggested that in searching for new foundations for understanding the role of the senior educator, three metaphors are used to describe him/her: the curriculum steward, the educator or teacher leader, and the community or school builder For the purpose of this qualitative study, the focus was on exploring the experiences of senior educators in the quality assurance of head of departments teaching materials that are meant to meet the standards of quality education as outlined in the assessment framework policy documents. The researcher used the metaphor as one of the lenses through which to study the senior educators who are declared part of the School Management Team. The term senior educator emerged after the implementation of the Occupational Specific Dispensation (OSD), which categorises serving educators in terms of their teaching experience as outlined in Resolution 5 of 2006 accepted by the Education Labour Relation Council (ELRC). A qualitative study using an interpretive, qualitative multiple studies were applied to explore the experiences of senior educators when requested to evaluate and moderate the teaching materials of HODs in the primary school. The following themes were considered as part of the investigation: Restructuring of education; challenges experienced by senior educators; the roles of senior educators; educator leadership; inclusive management; and the distribution of responsibility among educators. By sharing the experiences of the senior educators as found in this study, the study could serve as a valuable resource and lead to similar studies that could enhance the sharing of leadership experiences of senior educators to establish successful schools that produce quality education. The roles of the senior educators include the moderation of the teaching materials used by fellow educators; quality assurance of the work of educators; class visits; monitoring, evaluation and support of other educators; and organisation of departmental meetings and school-based workshops of the subjects assigned to them by the management of the school. Primary schools in South Africa experience problems when senior educators are to quality assure the teaching materials used by HODs, due to the fact that the latter may assume that the superior status of their position will shield them against criticism from senior educators. Even though these problems usually do not lead to a hostile relationship, they have an effect on the content depth of the curriculum taught to learners. The problems between senior educators and HODs emanate from their shared responsibility and accountability for curriculum management in relation to content depth; the alignment of the subject content taught with the curriculum pace setters; adherence to the assessment framework and pace setters; reporting to parents on the progress of learners, and communication with other stakeholders. All of these matters speak to the quality assurance of the work of educators in the school.
Dissertation (MEd)--University of Pretoria, 2015.
Education Management and Policy Studies
MEd

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Andersson-Wikström, Alexandra. "Potential Sources of Stormwater Pollutants : Leaching of Metals and Organic Compounds from Roofing Materials." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-46864.

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Runoff from paved surfaces in the urban environment is recognised as a major contributing source to deteriorated water quality. In stormwater, both various metals and organic compounds can be present and the quality of stormwater is dependent on e.g. the characteristics of the surfaces that the runoff encounters. Diffuse pollution sources, i.e. anthropogenic emissions from e.g. traffic or constructions, has been pointed out by the European Water Framework Directive to significantly contribute to pollution of stormwater receivers. In order to create and obtain a sustainable, liveable and aesthetical urban environment it is critical to be able to mitigate stormwater pollution, not least considering the increasing amount of stormwater due to climate change.The aim of this master’s thesis was to evaluate the potential release of inorganic- and organic stormwater pollutants from conventional roofing materials by laboratory leaching experiments. The study was mainly aimed to serve as a first screening on the roofing materials, in order to be able to select a number of materials for further investigation later on. The organic compounds included in this study were polycyclic aromatic hydrocarbons, nonylphenols and -ethoxylates, phthalates and herbicides. Previous research on stormwater pollution has mainly focused on metals and there is therefore a knowledge gap on organic compounds in urban runoff. The leaching experiments were designed considering previous similar studies. Synthetic rainwater was prepared based on measurements of rainwater quality in Sweden. Duplicates of 16 commonly used roofing materials were prepared and immersed in beakers of synthetic rainwater. The beakers were agitated on an orbital shaking device for 24 hours and pH as well as conductivity was recorded in the leachates before sending the samples to the contracted laboratory for analysis. Metals were analysed on all materials and the organic compound analyses were performed on selected materials based on each material’s composition and was limited with the substance’s probability to release from each material.From the analysis results, mean values for the leached concentrations of all duplicates were calculated. The annual potential release of substances from materials was estimated based on the leached concentrations and data on the average annual precipitation in Sweden, in order to get an indication of the order of magnitude of the pollutant release. The results showed a potential release of a number of the included substances from many of the studied roofing materials, in varying order of magnitude. The shingle roofing was the material that showed the ability to release the largest number of pollutants. Some materials e.g. the clay tile also showed potential to adsorb substances on the material surface. Metals were mainly released in dissolved form from most materials. Phthalates were not present in concentrations above report limits in the leachates from any of the studied materials. The results also indicate a significant different in the release potential from materials that were considered similar in their composition and expected to have similar leaching behaviour prior to the laboratory experiments, e.g. two similar felt roof materials from different manufacturers.

Validerat; 20150715 (global_studentproject_submitter)

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Namkoong, Gon. "Molecular beam epitaxy grown III-nitride materials for high-power and high-temperture applications : impact of nucleation kinetics on material and device structure quality." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/16426.

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Austin, Michael. "An investigation of the processing and reconstruction conditions necessary to optimize the transmissin hologram images formed using conventinal silver halide materials." Thesis, University of Westminster, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237408.

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Robinson, Daniel J. "A Delphi study to examine the quality measurement standards by online instructors using the Quality Matters Rubric as a basis for creating instructional materials." Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1491431111417877.

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Bevin, Emma, and Matilda Björklund. "Sample quality effects of laser cutting : An empirical study on the heat affected zone and the surface quality in laser cut samples." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277878.

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This study has been conducted with the aim to examine the extent of the heat affected zone in order to use laser cutting when making samples for tensile testing. When cutting with a laser the material absorbs heat energy from the laser beams which causes changes in the microstructure. The heat affected zone affects the properties of the materials, lowering the accuracy of the tensile test. Therefore, it is desired to know the extent of the heat affected zone in order to remove it before tensile testing. In this study two materials were used, the high strength steel Docol 1000DP and the duplex stainless steel LDX 2101. The materials were cut in the shape of dog bones for tensile testing using two different laser powers, 2500 W and 3500 W. The samples were cut with different cutting speeds, starting at lower cutting speed, increasing until the laser was unable to cut through. Thereafter, the heat affected zone, and the surface quality was examined. The results from this study showed that the heat affected zone decreases with increased cutting speed. When cutting with high cutting speeds in Docol 1000DP it is enough to turn away 0.30 mm in order to remove the heat affected zone with margin. Negligible difference in heat affected zone was observed between the samples cut with 2500 W and 3500 W. The heat affected zone in LDX 2101 was very small, in order of 50 μm, making it hard to measure. This resulted in no exact measurements being made. However, the heat affected zone was in the order of 50 μm for all samples, concluding that turning away 0.15 mm is sufficient to remove the heat affected zone with margin. No difference could be observed between the samples cut with a laser power of 2500 W or 3500 W. Common to both materials is that the amount of dross decreases with increased cutting speed.
Denna studie har utförts i syfte att undersöka utsträckningen av den värmepåverkade zonen för att kunna använda laserskärning för att skära prover till dragprovning. Ett problem med laserskärning är att metaller absorberar värmeenergin, vilket orsakar förändringar i mikrostrukturen. Denna värmepåverkade zon bör minimeras och avlägsnas från metallen, då det minskar kvalitén på proverna samt på dragprovningen. I denna studie har två material undersökts, det höghållfasta stålet Docol 1000DP och det duplexa rostfria stålet LDX 2101. Stålen skars ut i form av hundben för dragprovning med två olika effekter på lasern 2500 W och 3500 W. Proverna skars ut med olika skärhastigheter, började med lägre hastigheter och ökade sedan tills lasern inte längre kunde skära igenom materialet. Därefter undersöktes både den värmepåverkade zonen och kvaliteten på skärytan. Resultaten från denna studie visade att den värmepåverkade zonen minskar med ökad skärhastighet. Vid skärning i Docol 1000DP med höga skärhastigheter räcker det att avlägsna 0,30 mm för att ta bort den värmepåverkade zonen med marginal. Ingen skillnad i värmepåverkad zon observerades mellan proverna skurna med 2500 W och 3500 W vid skärning med högsta skärhastigheten för varje lasereffekt. Den värmepåverkade zonen i LDX 2101 var mycket liten, i storleksordningen 50 μm, vilket gjorde den svårt att mäta. Slutsatsen gav att det är tillräckligt att avlägsna 0,15 mm för att avlägsna den värmepåverkade zonen med marginal. Ingen skillnad kunde observeras mellan proverna skurna med en lasereffekt på 2500 W eller 3500 W. Gemensamt för båda materialen var att gradbildningen minskade med ökad skärhastighet.

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Bäck, Frida. "Influence of bio-coal ash respectively coal structure on coke production and coke quality." Thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76180.

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In recent years, the consequences of global warming have increased the discussion about the climate impact caused by humans and the fossil emissions. Sweden has decided to reduce the negative climate impact with a zero vision for the fossil carbon dioxide emissions in year 2045. In order to achieve this, great efforts and changes are needed both in the inhabitants' way of living but primarily in the base industry. The major cause is the use of fossil coal, which generates fossil carbon dioxide in the steel industry in particular. The fossil coal is added to the blast furnace in the steel process in forms of coke and coal, which reduces the iron and emits heat. The quality of the coke is important as it functions reducing agent, provides a mechanical support to the bed and enables the gas flow up through the blast furnace and enables dissolution of carbon in hot metal. Also, coke supplies energy from exothermic reactions between carbon and carbon dioxide that takes part in the blast furnace and the energy are further used for the heating and melting of the cold iron pellets. Due to these factors, the blast furnace process is dependent on coke for its function, which means that the entire process must be replaced if the steel production should work without fossil coal. However, there are many studies that have been done on how to replace some of the fossil coal with bio-coal, which is produced from biomass. If some of the fossil coal could be replaced by some bio-coal, this would mean that fossil carbon dioxide emissions would decrease and lead to a reduced climate impact. The process would still generate carbon dioxide, but on the other hand, a cycle would be formed because when biomass is grown, carbon dioxide is taken up, e.g. by the trees grown for this purpose. However, bio-coal does not have the same properties as fossil coal, which in turn affects the quality of the coke. Bio-coke is more reactive and more porous than fossil coke. In order to be able to replace fossil coke with bio-coke, it is likely necessary to pre-treat the biocoal before it replaces part of the fossil coal in the coke production. Bio-coal contains ash that acts as an internal catalyst. One theory is that if it is possible to produce a bio-coal with ash-free carbon structure, it can be used in the production of coke without having such a great effect on the coke quality. In this project, the ash's impact on the properties of bio-coal in coke was studied. Previous studies have shown that leaching is an effective method for removing ash from bio-coal. It can be leached in three different ways, either with water, weak acid or acid. However, it has been found that acid leaching has a certain impact on the carbon structure itself. For this reason, two types of bio-coal, torrefied Grot (forest residue) and torrefied sawdust were selected, which were leached both with water but also with weak acid in order to achieve an ash-reduced carbon structure. The acid selected was acetic acid, as it has been tested for similar purposes in previous studies. The leaching efficiency was evaluated by analysing the leachate with ICP-OES after leaching. According to the result, a significant part of the ash had been leached out, but the leaching with weak acid was much more effective than water leaching. To ensure that the carbon structure was not altered, light-optical microscopy was made which showed that the structure was intact. However, it was not possible to determine whether the pore sizes were changed after leaching and it is therefore relevant to investigate this further. Moreover, the leached II bio-coal replaced 5% of the fossil coal in the coal mixture for coke making. In addition to this, coke was also made with only the ash from the two bio-coals to see what effect the ash has on the coke quality. The result that was obtained from the TGA showed that the ash had a low impact on the reactivity of the coke. However, the coal structure of the coke had a great impact on the reactivity behaviour. Keywords: Bio-coke, bio-coal, leaching, ash, coke quality, carbon structures, torrefied sawdust

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Wallach, Jeremy C. (Jeremy Cole) 1975. "Solving a corrosion quality problem at a major US automaker." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/34756.

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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2004.
Includes bibliographical references (leaves 55-56).
This project addresses a corrosion quality problem at an automaker. The problem, hem flange corrosion, involves the appearance of red rust along edges of closure panels (doors, hoods, deck lids, etc) after three to four years in service. This project focuses on finding a solution for a particular new model. The project contains two parts: a technical treatment of hem flange corrosion and an organizational analysis. The technical discussion includes a root-cause analysis, failure analysis of past solution attempts, benefit/cost analysis of potential solutions, and technical recommendations. The organizational discussion examines why this automaker was challenged with implementing a solution.
by Jeremy C. Wallach.
S.M.
M.B.A.

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Baliso, Unathi. "Partnering with suppliers for quality improvement." Thesis, Cape Peninsula University of Technology, 2010. http://hdl.handle.net/20.500.11838/1232.

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A dissertation submitted in fulfillment of the requirements for the degree Master Technology: Quality in the Faculty of Engineering at the Cape Penisula University of Technology
Uneven surfaces on national roads that often lead to difficulty and even danger can be extremely hazardous when wet, due to mud and cracks, and also create dust pollution for motorists, pedestrians, residents and business. The continuing use of low quality raw materials in producing hot mix asphalt for national roads, leads to regular maintenance at a very high cost. The quality aggregates (stone that is used to produce asphalt), and the quality of bitumen are often inadequate for the correct composition of hot mix asphalt. The mst important factors affecting initial and long term performance of the highways is the inferior pavement structure and condition, due to poor aggregates (raw material)from suppliers. The performance of asphalt i s largely determined by the characteristics of its constituents, the asphalt binder and aggregates.

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Hansson, Peter. "The Sink-Effect in Indoor Materials : Mathematical Modelling and Experimental Studies." Doctoral thesis, KTH, Civil and Architectural Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3619.

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In this thesis the sink-effect in indoor materials wasstudied using mathematical modelling and experimental studies.The sink-effect is a concept which is commonly used tocharacterise the ability of different indoor materials to sorbcontaminants present in the indoor air. The sorption process ismore or less reversible, i.e. molecules sorbed in materials athigh contaminant concentrations may again be desorbed at lowerconcentrations. Knowledge of the sorption capacity of materialsand the rate at which sorption and desorption takes place is offundamental importance for mathematical simulation of indoorair quality. The aim of this work is to contribute withknowledge about how the sink-effect can be described inmathematical terms and how the interaction parametersdescribing the sorption capacity and sorption/desorptionkinetics can be determined. The work has been of amethodological nature. The procedure has been to set upphysically sound mathematical models of varying complexity andto develop small-scale chamber experiments. Two differentdynamic chamber methods have been used. One is based on amodified standard FLEC-chamber while the other uses a chamberwith two compartments, one on each side of the material. The"twin-compartment" method was designed due to the observationthat the contaminant readily permeated straight through theselected materials, which resulted in uncontrolled radiallosses in the FLEC-chamber. In order to be useful forcomparison between experiments and calculations and parameterfitting, the boundary conditions in the chambers must beprecisely known and controlled. This matter has shown to be themost crucial and difficult problem in the research. A varietyof mathematical models for the sink-effect have been proposed.In some models advanced fluid simulations were used in order totest the influence ofill-defined flow boundary conditions. Theaim of the modelling is to find a formulation with a minimum ofinteraction parameters, which is generally useful, i.e. both insmall-scale laboratory environments and in full-scale like anoffice room. Estimated model parameters are shown to be able toyield a reasonably good fit to experimental data for thesorption process but a less satisfactory fit for the desorptionprocess.

Keywords:sink-effect, sorption, adsorption, diffusion,indoor air quality, volatile organic compounds, VOC,contaminants, building materials

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Afonso, João Tomás Felgueiras Gomes. "Quality Control in additive Manufacturing - Capacity Assessment of non-touching methods." Dissertação, 2017. https://hdl.handle.net/10216/105957.

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Afonso, João Tomás Felgueiras Gomes. "Quality Control in additive Manufacturing - Capacity Assessment of non-touching methods." Master's thesis, 2017. https://hdl.handle.net/10216/105957.

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Dissertations / Theses on the topic 'Quality materials'

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