No description available.

Trial and error and the use of highly time-consuming methods are often necessary for investigation and characterization of nonlinear systems. However, for the rather common case where a nonlinear system has linear relations between many of its degrees of freedom there are opportunities for more efficient approaches. The aim of this thesis is to develop and validate new efficient simulation and experimental methods for characterization of mechanical systems with localized nonlinearities. The purpose is to contribute to the development of analysis tools for such systems that are useful in early phases of the product innovation process for predicting product properties and functionality. Fundamental research is combined with industrial case studies related to metal cutting. Theoretical modeling, computer simulations and experimental testing are utilized in a coordinated approach to iteratively evaluate and improve the methods. The nonlinearities are modeled as external forces acting on the underlying linear system. In this way, much of the linear theories behind forced response simulations can be utilized. The linear parts of the system are described using digital filters and modal superposition, and the response of the system is recursively solved for together with the artificial external forces. The result is an efficient simulation method, which in conjunction with experimental tests, is used to validate the proposed characterization methods. A major part of the thesis addresses a frequency domain characterization method based on broad-band excitation. This method uses the measured responses to create artificial nonlinear inputs to the parameter estimation model. Conventional multiple-input/multiple-output techniques are then used to separate the linear system from the nonlinear parameters. A specific result is a generalization of this frequency domain method, which allows for characterization of continuous systems with an arbitrary number of localized zero-memory nonlinearities in a structured way. The efficiency and robustness of this method is demonstrated by both simulations and experimental tests. A time domain simulation and characterization method intended for use on systems with hysteresis damping is also developed and its efficiency is demonstrated by the case of a dry-friction damper. Furthermore, a method for improved harmonic excitation of nonlinear systems using numerically optimized input signals is developed. Inverse filtering is utilized to remove unwanted dynamic effects in cutting force measurements, which increases the frequency range of the force dynamometer and significantly improves the experimental results compared to traditional methods. The new methods form a basis for efficient analysis and increased understanding of mechanical systems with localized nonlinearities, which in turn provides possibilities for more efficient product development as well as for continued research on analysis methods for nonlinear mechanical structures.

No description available.

In the present study, I look at the relationship between power and identity verification and the conditions under which this relationship can be disrupted. Specifically, I look at the role of information in disrupting power differences within identity processes. I examine these processes through an experiment with task-oriented, power-imbalanced, dyads (N=144). Priming participants with a task-leader identity, I test how the introduction of negotiation resources—or information discrepant and external to a high power actor’s self presentation, affect presentation power—or the degree to which an actor can maintain identity meanings in light of partner negotiations. In contrast with existing literature, I did not find a direct relationship between power and identity verification. I did, however, find that those in higher positions of power experience greater identity stability, while those in lower positions of power experience increased identity change. Interestingly, I found that identity change and identity verification varied with identity valence, such that those with dominant task leader identity meanings experienced greater identity stability but less identity verification than their more submissive counterparts. These relationships, however were power dependent, such that differences disappeared among power-high actors, and were magnified for power-low actors. Negotiation Resources did not have a significant main effect, but showed a significant interaction with identity valence when predicting identity verification among power-low actors.

The study was concerned with developing strategies that can be used to implement and operate a School Within A School (SWAS) program that may contain an action-learning component. The study began with an intensive search of the literature. Later, two data collecting instruments were developed: (1)a semi-closed-end questionnaire which was mailed to 112 SWAS programs as identified in the National Directory of Public Alternative Schools (Flaxman and Holmstead, 1978); and (2) an open-ended telephone interview instrument which was administered via telephone to ten respondents working in SWAS programs across the United States. Prior to use, the two instruments were submitted to a panel of five experts for review. Data from the semi-closed-end instrument were recorded and each telephone interview was tape recorded and then transcribed. A summary of the most significant findings, using data from both the instruments follows. The majority of the SWAS programs were implemented to deal with a particular group of students in a more effective manner. A substantial number of programs were implemented to deal with attendance and drop-out problems. Teachers proved to be the most likely group of professionals to call for a SWAS program. Teachers also proved to be the major stumbling block to successful program implementation. The respondents emphasized the importance of dealing with change effectively in order to successfully implement innovations. Involvement of the school community facilitated program implementation. SWAS programs have been implemented and operated in the face of a district's declining resources. The operating expenses of a majority of the SWAS programs were equal to or below operating expenses of the regular host school. The major problem encountered in implementing and operating a SWAS program is the philosophical division the concept promotes between faculty proponents and opponents. However, it was also funding that by successfully dealing with the fears and threats posed by change, program advocates can facilitate implementation and operation. Finally, it was found that SWAS programs offering an action-learning component can easily initiate and maintain communication and coordination with community resource personnel and on-site supervisors. Based on the findings of the study, it was recommended that: (1)SWAS programs be directed at providing either curriculum options or scheduling options; (2)prior to introducing the SWAS concept, a needs survey be conducted and school community participation be encouraged and fostered in all phases of planning, operation, and evaluation; (3)once the SWAS concept has been introduced, steps be taken to reduce the stress and fear attendant to change; (4)accurate program evaluation procedures be established that are sensitive to the goals and objectives of the SWAS program; (5)a SWAS program operate with the same per-pupil expenditure ratio as the host school; (6)lines of authority and responsibility be clearly delineated in the program proposal; and (7) community resource personnel be involved in planning, operating, and evaluating any action-learning component.

The study reported in this dissertation compares the learning effectiveness of two experimental methods that can be used in the teaching of kinematics to Grade 11 learners in Physical Science. The first method is the conventional ticker-timer experiment, while the second utilises high-technology microcomputer-based equipment. The purpose is to make recommendations for improved teaching of basic kinematics concepts and graphs, which learners have difficulties with (Halloun & Hestenes, 1985; McDermott et al., 1987). A group of 48 Grade 11 learners from Thuto-Boswa Secondary School, Ventersdorp, were used in the empirical research. They were divided into two groups of comparable abilities. Group A used the conventional apparatus and group B the microcomputerbased apparatus. The results of the pre- and post-tests were analysed statistically to compare the learning effectiveness of the two methods in terms of the outcomes reached, the gains obtained as well as d-values. Three months after the experiments were conducted the learners were tested again to determine the long-term effect of the methods. Both groups obtained a gain of approximately 0,2 in the pre- versus post-test analysis. The literature (e.g. Thornton, 1998) reveals larger gains with microcomputer-based experiments. Three possible reasons that could contribute to this discrepancy were investigated, namely the learners' acquaintance with the microcomputer, the educator's experience with the apparatus as well as the learners' cultural background and language. All three these factors were found to have a detrimental effect on the learning effectiveness, especially with the microcomputer-based method. Recommendations are made in connection with the teaching of basic kinematics concepts and graphs to Grade 11 learners in South African secondary schools. In addition, it is emphasised that educators should be adequately computer literate before expensive high-technology equipment is purchased for classroom use. It is also pointed out that the implementation of the computer as teaching aid can be a first step to improve computer literacy of disadvantaged learners in our schools. / Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2004.

The purpose of the study was to determine the attitudes of parents of students enrolled in non-IGE elementary schools of the Metropolitan School District of Washington Township, relative to existing educational programs provided in district non-IGE elementary schools, educational alternative preferences for elementary school students, and reporting of pupil progress to parents. The study population consisted of 1,244 parents from the 3,522 households having children enrolled in district non-IGE elementary schools. A survey instrument was developed consisting of fifty-five statement items, each utilizing a Likert scale with forced response. One instrument was sent to parents in each of the 8,522 households having children enrolled in district non-IGE elementary schools.The following summary of the findings is based on an analysis of parent responses received from the study population.1. Most responding parents expressed pride in the Washington Township non-IGE elementary schools and perceived the overall educational program quality of the schools as high, with children learning what parents preferred children to learn in school.2. Parents responding were generally satisfied with child-teacher relationships, student instruction, the degree of respect for individuals in school, and the degree of difficulty of educational materials.3. The majority of parent respondents perceived children as comfortable with the classroom atmosphere, experiencing successful school progress, and eager to go to school.4. Parent respondents generally indicated school rules, regulations, and policies were reasonable and that order and control in school should not be more strict.5. Most parents responding expressed positive attitudes toward existing parent-school relations.6. A majority of parent-respondents expressed satisfaction with the appropriateness of the report card parents received regarding student progress and did not perceive an over emphasis on grades by the school.7. Most parents preferred being kept informed of student progress through the use of parent-teacher conferences and written evaluations. The types of written evaluations most preferred by responding parents were check lists of specific skills in particular subjects and report cards utilizing A, B, C, D, and F grades.8. A majority of parents responding to survey items relative to alternative programs expressed interest in alternative educational programs for children.9. Parent respondents interested in alternative educational programs for children were almost evenly divided in opinion relative to a willingness to have children transported at least thirty minutes each way in order to attend preferred alternative educational programs.10. Parents expressing interest in alternative educational programs indicated a willingness to send children to schools with the following alternative educational programs, in descending order: Continuous Progress, Basic Fundamental, and Creative Arts.11. A majority of the parents expressing an opinion relative to the need for at least one junior high alternative educational program available to all junior high students in the township expressed a willingness to consider sending children to a junior high school with an alternative educational program.Study research and findings support the contention that school officials can advantageously survey parents as a means of securing parental attitudes, views, and expectations to plan more effectively for future educational programs.

The study reported in this dissertation compares the learning effectiveness of two experimental methods that can be used in the teaching of kinematics to Grade 11 learners in Physical Science. The first method is the conventional ticker-timer experiment, while the second utilises high-technology microcomputer-based equipment. The purpose is to make recommendations for improved teaching of basic kinematics concepts and graphs, which learners have difficulties with (Halloun & Hestenes, 1985; McDermott et al., 1987). A group of 48 Grade 11 learners from Thuto-Boswa Secondary School, Ventersdorp, were used in the empirical research. They were divided into two groups of comparable abilities. Group A used the conventional apparatus and group B the microcomputerbased apparatus. The results of the pre- and post-tests were analysed statistically to compare the learning effectiveness of the two methods in terms of the outcomes reached, the gains obtained as well as d-values. Three months after the experiments were conducted the learners were tested again to determine the long-term effect of the methods. Both groups obtained a gain of approximately 0,2 in the pre- versus post-test analysis. The literature (e.g. Thornton, 1998) reveals larger gains with microcomputer-based experiments. Three possible reasons that could contribute to this discrepancy were investigated, namely the learners' acquaintance with the microcomputer, the educator's experience with the apparatus as well as the learners' cultural background and language. All three these factors were found to have a detrimental effect on the learning effectiveness, especially with the microcomputer-based method. Recommendations are made in connection with the teaching of basic kinematics concepts and graphs to Grade 11 learners in South African secondary schools. In addition, it is emphasised that educators should be adequately computer literate before expensive high-technology equipment is purchased for classroom use. It is also pointed out that the implementation of the computer as teaching aid can be a first step to improve computer literacy of disadvantaged learners in our schools. / Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2004.

Orientador : Yong Kun Park / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e Agricola / Made available in DSpace on 2018-07-14T03:25:48Z (GMT). No. of bitstreams: 1 Baldini_VeraLuciaSignoreli_M.pdf: 18939700 bytes, checksum: 2ab82f9ad9029b92a0d0a1ca1c64861d (MD5) Previous issue date: 1985 / Resumo: As propriedades das b-galactosidases da soja e do feijão, purificadas por fracionamento com sulfato de amônio, cromatografia em DEAE-celulose e filtração molecular em Sephadex G-100 foram examinadas.A filtração em Sephadex G-100 produziu duas frações, designadas I e II, com diferentes pesos moleculares. As formas I e II de cada amostra mostraram diferenças em seus valores de pH e temperatura ótima, energia de ativação, Km e Vmax com PNPG, melibiose ou rafinose como substratos. Não se observaram diferenças em suas estabilidades ao calor e à variação de pH.As enzimas apresentaram atividade máxima entre pH 5,0 e 6,0 e foram estáveis na faixa ao redor do pH ótimo; os valores de temperatura ótima ficaram entre 45 e 55ºC e as atividades enzímicas perma-neceram estáveis até 50ºC e todas elas mostraram maior especificidade para o PNPG. Íons metálicos como Ag+ e Hg+2 causaram completa perda de atividade; entretanto, as enzimas não foram sensíveis aos reagentes sul-fidrílicos, sugerindo não haver necessidade de grupos - SH para a atividade catalítica. As enzimas foram inibidas competitivamente por glicose, mais intensamente por galactose e não competitivamente por frutose. As duas formas enzímicas do feijão foram inibidas por al--tas concentrações de PNPG / Abstract: B-Galactosidases from soybean (Glycine max) and feijão (Phaseolus vulgaris) seeds were purified by ammonium sulfate fractionation, chromatography on DEAE-cellulose and gel filtration on Se-phadex G-100, and studied their characteristics. It was found that b-galactosidase was multiple forms, which was consisted of two frac-tions (fraction I and II). Fractions I and II of each sample exhibited differences in their optimal pH and temperature, activation energy, Km and Vmax values with PNPG, melibiose or raffinose as substrates. The properties of the enzymes from these seeds resembled each other with respect to their pH and thermal stabilities. The enzymes showed maximum activity between pH 5.0 and 6.0 and were stable in and around this range. The optimal temperature values were observed between 45 and 55ºC and the enzymes were stable up to 50ºC. All forms were more specific for PNPG. Metal ions such as Ag+ and Hg+2 caused complete loss of activity and sulfhydryl reagents had no effect on the enzyme activities, indicating that the -SH group is not involved in the catalytic site. Glucose and galactose inhibited the enzymic activities competitively, whereas fructose had a non-competitive effect. Two forms of Phaseolus vulgaris b-galactosidase were inhibited by PNPG at high concentrations / Mestrado / Mestre em Ciência de Alimentos

Fighting for Status investigates how status concerns affect states’ decisions in the domain of international security. Ironically, while there is widespread agreement within the political science discipline and the foreign policy community that status matters, there exists relatively little in the way of focused research on how and when it does so. Thus, our understanding of status in international politics has been guided so far by intuition, not by evidence, and this has left us with a significant gap in our understanding of how status affects foreign policy behavior and international outcomes. Relying on the assumption that ‘status matters’ has left us with no extant theory of variation in states’ concern for status and little understanding of its specific implications for foreign policy or international conflict. What is needed –and what my research is designed to provide –is a systematic investigation into the ways in which the desire to increase or prevent the loss of status affects the behavior of states and leaders, especially as these concerns relate to the propensity for violent conflict. Using a diverse array of methods and data, I provide evidence on the relationship between status concerns and conflict. I use a large-n, cross-national analysis to investigate the effects of status dissatisfaction on international conflict at several degrees of intensity. I find that states that are attributed less status than they are due based on material capabilities are overwhelmingly more likely (than satisfied states) to initiate militarized disputes at almost every level of intensity. Two case studies –focusing on Germany and Russia in the World War One era –corroborate these patterns in historical cases of great importance and help to form a more complete picture of how status concerns affect political decision-making. Finally, I use a laboratory experiment and a unique sample of real-world political and military leaders to shed light on the causal pathways through which status concerns affect escalation behavior. Here I find that negative emotions are a key pathway through which concerns over relative status impair judgment and decision-making. / Government