The aim of this thesis is to design, implement and evaluate an experiment that verifies the influence the size effect on selected parameters of the surface integrity. For the experiment were used highly productive reaming head MT3 made by HAM-FINAL. Evaluation of the surface integrity was done in terms of the characteristics of the surface roughness, geometric tolerances and changes in microstructure. Furthermore, the influence of the depth of chips evaluated for changes in the feed force, cutting torque and changes in specific cutting energy. The theoretical part deals with the description of the size effect, characteristic reaming, surface integrity, preparation of material and identification of highly productive MT3 reaming head.

A laboratory process exists for the extraction of kafirin protein from sorghum grain in order to form kafirin encapsulating microparticles. This laboratory process extracts approximately 2 g of protein and takes in excess of 60 hours from start to finish. A scaled-up extraction process based on the current laboratory process, consisting of a 100 L extraction vessel, was established in order to extract large volumes of kafirin protein from sorghum grain. Approximately 2.5 kg of kafirin protein, which contained approximately 80 % protein after defatting, was extracted from red sorghum grain. This blended kafirin protein, which was the product of combining 9 batches done on the up-scaled process, was needed in order to obtain a consistent base raw material for further experimentation. The blended kafirin was used to investigate the formation of kafirin encapsulating microparticles. This was achieved by means of the solvent phase separation technique with acetic acid as the solvent phase. A series of experiments, selected from a partial factorial design, were used to screen how the formation of microparticles was affected by various parameters. The parameters investigated were solvent to protein ratio, stirring speed, water addition rate and number of water droplets. The morphology of the various microparticles produced was analysed by means of light microscopy, FTIR and particle size analysis, and the different formed microparticles characterised. From the screening partial factorial experimental design, it was determined that the acetic acid concentration was crucial for the formation of microparticles. Microparticles did not form at a low mass ratio (2.3) of glacial acetic acid solvent to protein. Water addition rate and stirring rate also affected microparticle formation while the number of water droplets was insignificant. Therefore, using a high solvent to protein mass ratio (6.8), additional refined partial factorial experiments were conducted. These experiments focused on the effect of water addition rate and stirring speed on the final kafirin microparticle size. Ultimately, a polynomial model was developed to predict the final kafirin microparticle size using only the water addition rate and stirring speed as inputs. The model had an R2 value of 0.986 and was found to relatively accurate during validation. The model also identified that three distinct regions existed within the workspace: _ A region containing large particles due to protein mass agglomeration and crosslinking, which occurs at low stirring speeds (< 400 rpm) and high water addition rates (> 5 mL/min) _ A region where only small individual microparticles exist, which occurs at high stirring speeds (< 800 rpm) and low water addition rates (> 2 mL/min) _ A region where moderate particles existed as uniform agglomerates of the microparticles, which occurs at moderate stirring speeds (+- 600 rpm) and moderate water addition rates (+- 3.5 mL/min) Ultimately these kafirin microparticles, prepared from protein extracted in an up scaled process, were used to form qualitative microparticle films. The microparticle films were made without plasticiser and without dewatering the microparticles. Furthermore these films were made from microparticles in the regions identified in the model. This qualitative film formation showed that agglomerated microparticles can form films. This could be beneficial for the feasibility of a commercialised process for kafirin microparticle films since the production time would be shorter and less energy intensive. / Dissertation (MEng)--University of Pretoria, 2016. / Chemical Engineering / MEng / Unrestricted

A consequence of the recent mergers affecting General Electric Aerospace, Martin Marietta and Lockheed has been the need to exchange information between, previously unrelated, work sites. One of these work sites is the Martin Marietta Data Center (MMDC). The information exchange is to be performed electronically to maximize efficiency. No capability exists within the MMDC to accommodate this information exchange. <p>A number of options that address this deficiency exist. The most plausible is the installation of a computer program on the MMDC's LAN that would enable the required information exchanges to take place. <p>In order to make the computer program operational, modifications to the computers that make up the MMDC LAN are necessary. Primarily, the amount of RAM the computers possess must be increased. This results in a change in the amount of swap space that must be available. <p>The intent of this project is to resolve the deficiency that exists by enabling the MMDC to exchange data electronically with other sites in the area. <p>A secondary goal of the project is to determine a better way of allocating swap space than the present method of simply using twice the amount of RAM. <p>The approach to the project is "two-pronged". An assessment of the mechanics of swapping is performed to see if it could be done more efficiently. And, an analysis of an operational network is performed to determine the empirical relationship between swap space and RAM. Retaining performance standards is an underlying requirement for reaching any conclusions. <p>By using a single formula to determine swap space needs for every network, it is implied that the swap space to RAM size relationship is the same for every network. What is unique about the methods used in this project is that actual relationships and utilization of the network in question are used in determining the swap space size requirements. / Master of Science

In parasites, there are several examples of changes in genome size linked to a parasitic lifestyle—with some species having greatly reduced or expanded genome sizes relative to free-living non-parasitic relatives. What is unknown is whether there is correlated evolution between genome size and host specialization, and whether there is a generalizable framework in predicting genome size evolution in parasites using their genetic architecture and host use ecology. Here, I tested whether genome size of 96 eukaryotic parasites across a wide variety of taxa correlates with host specialization, quantified by the number and phylogenetic relatedness of host species they parasitize. I did not find that genome size and host specialization shared a correlated phylogenetic history; however, I did find that ectoparasites tended to have larger genomes then endoparasites, and that parasitic fungi had more host species then either animal or protozoan parasites. Although no clear trends in the evolution of genomes and host specificity were observed among parasites, my study was significantly limited by gaps in both genome size and host range availability. Future research should seek to address these gaps, as well as improve taxonomic coverage of data, so that trends in the evolution of parasite genome architecture could be adequately tested and delineated.

Plus size är ett växande kundsegment som idag har blivit i stort sett negligerat av klädbranschen både nationellt och internationellt. Med ett begränsat utbud och brist på inspirerande butiksavdelningar har allt fler konsumenter slutat att handla i fysisk butik och istället övergått till att handla på nätet. Detta har inspirerat till en undersökning av hur svenska kvinnliga modemedvetna plus size konsumenter i olika åldrar upplever fysiska klädbutikers servicescape. I studien har en kvantitativ metod, surveyundersökning online, genomförts där bekvämlighetsurval använts som grund. 121 modemedvetna plus size kvinnor uttryckte sin åsikt angående sina upplevelser av fysiska butikers servicescape och hur produkterna upplevs. I enkäten gjordes en medveten uppdelning av frågorna gällande fysiska butiker, ena butikskonceptet har en specifik plus size avdelning och den andra har sitt plus size sortimentet integrerat med det övriga sortimentet i butiken. Efter genomförd deskriptiv och statistisk analys av det insamlade materialet har det kunnat fastställas att plus size konsumenter anser att det finns skillnader mellan butiker med enskild avdelning och butiker med integrerat sortiment. Den allmänna upplevelsen bland respondenterna var att servicescape genomförts bättre i butiker där plus size produkter är integrerade bland det övriga sortimentet. Utbudet av produkter i plus size upplevs vara begränsat. Det är därför svårt att avgöra hur servicescape påverkar uppfattningen av produkter. Dock uppfattas plus size avdelningars servicescape negativt och detta kan påverka konsumenters upplevelse av produkter och dess tillgänglighet. Studien har bidragit med nya insikter i hur det specifika kundsegmentet, plus size kvinnor, upplever servicescape. Vidare har studien bidragit till forskning gällande butiker med integrerat utbud då tidigare forskning inom detta område varit begränsat. / Plus size is a growing consumer segment that have become neglected in the clothing industry both nationally and internationally. With a limited supply and a lack of inspiring departments in store, more consumers have stopped shopping in physical stores and instead directed their shopping towards online retailers. These factors have inspired this study and the need to investigate how Swedish female fashion forward plus size consumers in different ages experience physical store environments in terms of servicescape. The study is based on a quantitative method where convenience sample was used. 121 female plus size consumers took part in an online survey to express their experiences of servicescape and how products are perceived in these environments. The survey was deliberately divided into two different parts where one part focused on stores that have a specific department for plus size clothing and the other where the plus size assortment was integrated with the other ranges in store. After conducted descriptive and statistical analysis of the compiled material, the study shows that female plus size consumers deem that there is a difference between the experienced servicescape of the two different types of store. The general conception among the respondents is that the stores where the plus size assortment is integrated have a better applied servicescape. The range of products in plus size was experienced to be limited. Because of this is has been hard to determine werther servicescape have a big impact on how products are perceived or not. However, since the study shows that plus size departments in terms of servicescape are perceived negatively, this may have an effect on how the products and its availability are perceived. The study has contributed with new insights into how the specific consumer segment, female plus size, experience servicescape. Furthermore, the study has contributed with new knowledge regarding the experience of stores with an integrated plus size assortment since this particular angle has been limited in earlier studies.

Frame aggregation is one of the major MAC layer enhancements in the IEEE 802.11 family that boosts the network throughput performance. It aims to achieve higher throughput by transmitting huge amount of data in a single transmit oppor- tunity. With the increasing awareness of energy e ciency, it has become vital to rethink about the design of such frame aggregation protocol. Aggregation techniques help to reduce energy consumption over ideal channel conditions. However, in a noisy channel environment, a new energy-aware frame aggregation scheme is required. In this thesis, a novel Green Frame Aggregation (GFA) scheduling scheme has been proposed and evaluated. GFA optimizes the aggregate size based on channel quality in order to minimize the consumed energy. GFA selects the optimal sub-frame size that satisfies the loss constraint for real-time applications as well as the energy budget of the ideal channel situations. The design, the implementation, and evaluation of GFA using testbed deployment is done. The experimental analysis shows that GFA outperforms the conventional frame aggregation methodology in terms of energy e ciency by about 6⇥ in the presence of severe interference conditions. Moreover, GFA also outperforms the static frame sizing method in terms of network goodput and maintains almost the same end- to-end latency.

This dissertation explores the effectiveness and consequences of three distinct education policies. The first chapter analyzes the effects of high school exit exams on graduation, employment and wage outcomes. We construct a state-graduation year cohort dataset using the Current Population Survey data, US Census data and information on the timing and difficulty of exit exams in different states. Using this dataset we analyze within-state variation in outcomes overtime. Overall, we find relatively modest effects of high school exit exams. We do not find consistent effects on graduation rates for exit exams that assess academic skills taught below the high school level; however, we find that more challenging standards-based exams reduce graduation rates. We also find that about one-half of the reduction in graduation rates associated with exit exams is offset by an increase in GED rates. Our analysis of labor market outcomes suggests that exit exams increase employment rates, but we find no effect of exit exams on the distribution of wages. Chapter two analyzes the institutional consequences of the California Class-Size Reduction (CSR) program. This program provides incentive funding if schools limit the class-size in grades K-3 to twenty or fewer students. We find that some schools and school districts limit their enrollment levels in order to maximize the CSR subsidy payment. In particular, the distribution of grade and district enrollments exhibits a prominent pattern of peaks that occur at multiples of twenty, where CSR payment is the largest. In order to achieve exact enrollment levels, schools must be reassigning students above the desired thresholds to nearby schools or nearby school districts. We also find that schools that limit their enrollments are well-performing schools with a low percentage of students who receive free or reduced price meals. The last chapter analyzes the academic consequences of the Texas Top 10 Percent Law. In 1998, state universities in Texas began using high school class rank as the sole factor in university admissions. This policy was implemented to increase enrollment of minority and economically disadvantaged students, but it generated criticism that such beneficiaries of rank-based admissions lack the academic preparation necessary to perform well in college. I test this claim by analyzing academic performance of rank-eligible students who attended UT Austin before and after the law. To account for grade inflation I use a difference-in-differences framework with students not eligible for rank-based admissions as controls. The difference-in-differences estimates may be overstated, however, because academic quality of the control group may have increased after the law. I use propensity score matching methods to correct for this. Finally, I correct for the confounding effects of GPA ceiling on the difference-in-differences estimates. Both the baseline and the adjusted estimates suggest that mean college GPA of rank-admitted students declined after the law.

Thesis advisor: Hideo Konishi / The majority of this work focuses on the theoretical analysis of collective action, group efficiency, and incentive mechanisms in team contests where individual outlays of heterogeneous agents are not observable. The reward allocation within the group is instead dependent on observable worker characteristics, modeled as individual abilities, as well as on the observable level of aggregate output. I study the incentives for free-riding and the group-size paradox under a very general set of intra-team allocation rules. I further derive the optimal allocation mechanism which rewards agents according to a general-logit specification based on their relative ability. I derive conditions under which a team's performance is most sensitive to the ability of its highest-skill members, while at the same time higher spread in the distribution of ability has a positive effect on group output. In the final chapter I shift attention to the problem of optimal player order choice in dynamic pairwise team battles. I show that even if player order choice is conducted endogenously and sequentially after observing the outcomes of earlier rounds, then complete randomization over remaining agents is always a subgame perfect equilibrium. The zero-sum nature of these type of contests implies that expected payoffs for each team are independent of whether the contest matching pairs are determined endogenously and sequentially or announced before the start of the game. In both cases the ex-ante payoffs are equivalent to those when an independent contest organizer randomly draws the matches. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

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An investigation of austenite grain growth of two bearing steel grades; 100Cr6 and100CrMnMoSi8-4-6 is performed. Austenitization treatments were performed between 860°C and 1200 °C for 5 minutes to 5 hours and the grain size was determined for each sample.Grain boundary etching was carried out using a water based, picric-acid etchant. Generally,100CrMnMoSi8-4-6 was harder to etch than 100Cr6. Therefore, a precipitation heattreatment was performed in order to facilitate etching of prior austenite grain boundaries in100CrMnMoSi8-4-6. The precipitation treatment was found to be effective. However, theprecipitation heat treatment was not suitable for 100Cr6 as the grain size increased duringthe precipitation heat treatment.Light optical microscope equipped with a camera was utilized to take micrographs for grainsize evaluation. Jeffries' standard procedure according to ASTM E112-96 was used tomeasure the grain size. The results shows that the austenite grain size increases withtemperature and time as expected. The experimental data was fitted to a well-known graingrowth model. The model only worked for the temperatures investigated and could not bemade to fit different temperatures.Local grain size variation was studied and its influence on fatigue properties was evaluated.The result showed that variation in local grain size can significantly alter the fatigueproperties. The findings are only theoretical and have not been tested practically.Two different spheroidization heat treatments and one homogenization heat treatmentwere performed. Both spheroidization heat treatments investigated exhibited similar grainsize. The homogenization heat treatment reduced the local grain size variation.Homogenization treatment prior to the spheroidization treatments did not increase ordecrease the grain size. The long heating, holding and cooling times in the secondspheroidization heat treatment is probably the reason for the lack of grain refinementcompared to the first spheroidization heat treatment. The grains had time to grow to theinitial austenite grain size during each cycle.