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This Master's thesis deals with determination of nucleobases in formamide samples (pure or catalyzed form) after their initiation by high-power density energy events. The theoretical part states the reader to the problems of prebiotic chemistry and acquaints him with the various theories of the origin of the nucleobases. The experimental part deals with the analysis of the samples initiated by Laser System PALS, which was used for the simulation high-power density energy events. For the identification and determination of the final products of laser plasma initiated chemical reactions in the gaseous phase of the samples was used the Fourier Transform Infrared Spectroscopy. The liquid part of the samples and the nucleobases in this part were analyzed by the gas chromatography with the mass detection.

<p>High-performance fibers used for ballistic protection are characterized by having outstanding mechanical properties such high modulus and strength. These mechanical properties are granted by the fiber’s chemical and physical structure as well as their high degree of orientation. Twaron fibers are one of the most commonly used fibers on soft body armors such as bulletproof vests. They are made from poly (p-phenylene terephthalamide) (PPTA), a rigid-rod and highly crystalline polymer. Although these fibers are crystalline and have great mechanical properties, their performance can decrease when they are exposed to different degradation factors. Free volume is the unoccupied space between the polymer molecules. It is responsible for characteristics such as diffusion and viscosity. Hence, the free volume changes as the polymer degrades. This thesis focuses on the effects of sonication, pH changes, and sweat on the free volume of PPTA fibers. </p><p><br></p> <p>A non-destructive technique known as positron annihilation lifetime spectroscopy (PALS) was used to measure the free volume in PPTA. Changes in the free volume of fibers degraded under different conditions were compared to their mechanical performance. Degradation in DI water, pH 4 and pH 10 aqueous solutions was conducted for 10 weeks at 80^oC. Sweat degradation of PPTA fibers was also conducted for 10 weeks at 25^oC, 50^oC, and 100^oC. Fibers degraded in pH4 and sweat solutions had greater loss of mechanical performance and changes in the free volume. PALS was able to detect changes in the nanostructure of PPTA fibers at early stages of degradation. This data was supported by mechanical tests and is complementary to other characterization techniques such as small angle X-ray scattering (SAXS). Results of this research are a steppingstone for future studies on lifetime predictions of bulletproof vests and the development of the next generation of soft body armors. </p>

Southern U.S. teachers at suburban high schools can use Edmodo; however, teachers prefer traditional teacher-centered teaching methods. This quantitative correlative study explored teachers' technology acceptance in relation to teaching styles and experiences. Framing acceptance by Davis's technology acceptance model (TAM), research questions addressed the direct and moderating relationships between teaching style and the TAM variables related to using Edmodo and the direct and moderating relationships between teaching experiences and TAM variables. From 240 teachers at the high school, 45 completed an online survey (response rate of 18.75%). Descriptive statistics, ANOVA, and regression analyzed data. TAM could be verified for the entire sample; however, no significant direct relationship between teaching style and the TAM variables was found. Teaching style moderated the relationships within the TAM; these were stronger for teachers with a teacher-centered teaching style. No significant direct relationship existed between teaching experiences and TAM variables; a moderating effect on the relationships existed within the TAM. Among experienced teachers, ease of use was the strongest acceptance predictor, whereas perceived use was the strongest predictor among less experienced teachers. Results indicated teachers might develop a more student-centered teaching style, thus concentrating on technology's ease of use, rather than its potential utility. A policy recommendation could ensure teachers efficiently used technology to support student-centered learning. The application of the recommended policies might lead to teachers' more effective use of instructional technology, which might affect student learning and motivation.

This thesis systematically investigates the effects of a recently developed modified ageing procedure of aluminium alloys, termed the T6I6 temper, on the microstructural development and mechanical properties of the Al ??? Mg ??? Si - Cu alloy 6061. For the T6I6 temper, a conventional single stage T6 temper is interrupted by an ageing period at a reduced temperature (65??C) to facilitate secondary precipitation, before resuming the final ageing at the temperature of the initial T6 treatment. The T6I6 temper was found to cause simultaneous increases in tensile properties, hardness, and toughness as compared with 6061 T6. Al ??? Mg ??? Si ??? Cu alloys are medium strength alloys widely used in the automotive industry and their further improvement is underpinned by stringent demands for weight reduction placed on the transportation industry in recent years. The potential for further improvement of the mechanical properties was found in the control of secondary precipitation that may take place even in some fully aged alloys when exposed to reduced temperatures. The overall improvement in the mechanical properties of 6061 T6I6 was attributed to the formation of finer and more densely dispersed precipitates in the final microstructure. The refinement of precipitates was facilitated by control of the precipitation processes and gradual evolution of the microstructure throughout each stage of the T6I6 treatment. The results indicated that the concentration and the chemical environment of the vacancies controlled the precipitation processes in this alloy. Findings also show that the proportion of the different precipitate phases present in the final microstructure, as well as the amount of the solute in these precipitates, can be controlled and modified utilizing secondary precipitation. A number of analytical techniques were used in this study. The evolution of the microstructure was studied using Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM) and Three Dimensional Atom Probe (3DAP). Vacancy-solute interactions were studied using Positron Annihilation Lifetime Spectroscopy (PALS) and 3DAP. The distribution of the solute was studied using 3DAP and Nuclear Magnetic Resonance (NMR). Differential Scanning Calorimetry (DSC) was used to identify precipitation reactions and to determine the stability of vacancy-associated aggregates.

This thesis systematically investigates the effects of a recently developed modified ageing procedure of aluminium alloys, termed the T6I6 temper, on the microstructural development and mechanical properties of the Al ??? Mg ??? Si - Cu alloy 6061. For the T6I6 temper, a conventional single stage T6 temper is interrupted by an ageing period at a reduced temperature (65??C) to facilitate secondary precipitation, before resuming the final ageing at the temperature of the initial T6 treatment. The T6I6 temper was found to cause simultaneous increases in tensile properties, hardness, and toughness as compared with 6061 T6. Al ??? Mg ??? Si ??? Cu alloys are medium strength alloys widely used in the automotive industry and their further improvement is underpinned by stringent demands for weight reduction placed on the transportation industry in recent years. The potential for further improvement of the mechanical properties was found in the control of secondary precipitation that may take place even in some fully aged alloys when exposed to reduced temperatures. The overall improvement in the mechanical properties of 6061 T6I6 was attributed to the formation of finer and more densely dispersed precipitates in the final microstructure. The refinement of precipitates was facilitated by control of the precipitation processes and gradual evolution of the microstructure throughout each stage of the T6I6 treatment. The results indicated that the concentration and the chemical environment of the vacancies controlled the precipitation processes in this alloy. Findings also show that the proportion of the different precipitate phases present in the final microstructure, as well as the amount of the solute in these precipitates, can be controlled and modified utilizing secondary precipitation. A number of analytical techniques were used in this study. The evolution of the microstructure was studied using Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM) and Three Dimensional Atom Probe (3DAP). Vacancy-solute interactions were studied using Positron Annihilation Lifetime Spectroscopy (PALS) and 3DAP. The distribution of the solute was studied using 3DAP and Nuclear Magnetic Resonance (NMR). Differential Scanning Calorimetry (DSC) was used to identify precipitation reactions and to determine the stability of vacancy-associated aggregates.

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The aim of this essay is to examine how boys and girls between 9–14 years old are portrayed in pen pal ads from the latter part of the 20th century. The source material consists of pen pal ads published in the newspaper Expressen during the years 1976–1977 and 1986–1987. With a qualitative content analysisas selected method, and an intersectional perspective with focus on gender and age, the content of the pen pal ads has been studied and analysed. The result shows that themes like sports, music, idols, and animals are a part of the descriptions in almost all the ads. Based on the content of the ads, the themes and other descriptions, different ideals have emerged for boys and girls. The ideals shift between the different periods. For example, the boys’descriptions during 1976–1977 shows that sports are an interest that belongs to an ideal for boys. Not only do they mention sports more often than girls, they also, to some degree, mention different sports than girls. During 1986–1987 the result shows that the girls have increased their interest in sports, and the boys have developed a greater interest for music and idols. The girls also start to mention sportactivities that previously almost only were mentioned by boys. During both periods there are both girls and boys who go against the ideals of their own sex and mentions interests that belong to the ideal of the opposite sex. Age may have had an impact on who within the different sexes that breaks the ideal. There are also some areas within the different themes that are of more interest to a boy or a girl of a certain age. However, gender is the strongest factor, which create the biggest differences between how boys and girls are portrayed in their pen pal ads.

No / Worldwide healthcare systems are facing immense changes in the demand of care with vast cost explosions caused by aging populations and the increase in chronic and mental diseases. The move towards patient-centered healthcare seems to be an ideal approach to meet future challenges but still clashes with reality. Patient Advice and Liaison Service (PALS) in the UK is one of the unique examples of patient empowerment to influence changes in healthcare systems like the National Health Service (NHS). The purpose of this paper is to look at user-driven organizational change management in PALS in retrospect to learn from its ‘best’ and ‘worst’ practices. In conclusion, patient-centered healthcare becomes more realistic if healthcare users and workers are empowered at the same time. The vision of patient, public, and staff involvement in the move towards patient-centered health needs to be backed up by adequate and secure resources as well as consistent organizational leadership and change management. Organizational change processes in general should be seen as biological continuous cycles with unpredictable evolutionary turning points rather than linear progressions. This helps to stay optimistic and embrace change as challenging, exciting, and difficult all the way through the change process.