Phonon spectra and thermal properties of some fcc metals using embedded-atom potentials /

By employing the embedded-atom potentials of Mei et ai.[l], we have calculated the dynamical matrices and phonon dispersion curves for six fee metals (Cu,Ag,Au,Ni,Pd and Pt). We have also investigated, within the quasiharmonic approximation, some other thermal properties of these metals which depend on the phonon density of states, such as the temperature dependence of lattice constant, coefficient of linear thermal expansion, isothermal and adiabatic bulk moduli, heat capacities at constant volume and constant pressure, Griineisen parameter and Debye temperature. The computed results are compared with the experimental findings wherever possible. The comparison shows a generally good agreement between the theoretical values and experimental data for all properties except the discrepancies of phonon frequencies and Debye temperature for Pd, Pt and Au. Further, we modify the parameters of this model for Pd and Pt and obtain the phonon dispersion curves which is in good agreement with experimental data.

A study of self-directed learning at an Ontario college of applied arts and technology

Ontario Colleges of Applied Arts and Technology (CAATs) are currently in the process of restructuring to ensure quality, accountability, and accessibility of college education. References to learner involvement and self-directed learning are prevalent. "Alternative delivery" and "paradigm shift" are current buzzwords within the Ontario CAAT system as an environment is created supportive of change. Instability of funding has also dictated a need for change. Therefore, a focus has become quality of learning with less demand on public resources. This qualitative case study was conducted at an Ontario CAAT to gather descriptive, perceptual data from post-secondary community college educators who were identified as supportive of self-directed learning and from post-secondary, traditional-aged college students who were perceived by their educators to be selfdirected learners. This college was selected because of initiatives to modify its academic paradigm to encourage what was reputed in the Ontario CAAT system to be self-directed learning. The purpose of this study was to investigate how postsecondary, traditional-aged college students and their educators perceive self-directed learning as part of the teaching-learning experience within a community college setting. Educator participants of the study were selected based on the results of a teaching and learning survey intended to identify educators supportive of self-directed learning. A total of 317 surveys were distributed to every full-time educator at the sample college; 192 completed surveys were returned for a return rate of 61 %. Of these, 8% indicated instructional beliefs and values supportive of self-directed learning. A purposive sample of six educators was selected using a maximulp variation sampling strategy. A network selection sampling strategy was used to select a purposive sample of seven post-secondary students who were identified by the sample educators as selfdirected learners. The results of the study show that students and educators have similar perspectives and operating definitions of self-directed learning and all participants believe they either practice or facilitate self-directed learning. However, their perspectives and practices are not consistent with the literature which emphasizes learner autonomy or control in course structure and content. A central characteristic of the participants represented in this study is the service-oriented professions with which each is associated. Experientiallearning opportunities were highly valued for the options provided in increasing learner independence and competencies in reflective practice. Although there were discrepancies between espoused theory and theory in practice in terms of course structure, the process of self-directed learning was being practiced and supported outside the classroom structure in clinical settings, labs and related experiences.

Instructor support for self-directed learning in higher education

This study addressed the problem of instructor support for self-directed learning, specifically, learner-directed program planning, within a classroom setting in higher education. A combination of survey, interview, document analysis, and observation was used to assess and evaluate the attitudes and practices of a sample of full-time faculty at an Ontario university. Eighty-seven percent of the study sample reported instructional beliefs, values, and expectations that were not supportive of self-directed learning, especially in terms of student participation in program planning. Planning was seen as the responsibility of the instructor. Instructors were least open to student participation in the planning of the evaluation of learning. However, there was considerable stated support for other of the basic principles of adult education. The remaining 13% of the study sample reported instructional beliefs, values, and expectations that were fully supportive of self-directed learning. Instructional practices were analyzed in relation to the instructors' stated beliefs. Although practices reflected, in many instances, instructors' statements of support, there were some significant discrepancies between apparent support for the concept of self-directed learning and actual classroom practice. Both beliefs and practice were compared to a research model of self-directed learning. Most instructors did not have a concept of self-directed learning as comprehensive as that described in the research model. Instructor support for self-directed learning was profoundly influenced by the university setting. It was concluded that more strenuous attempts to research, enhance, and promote instructional and institutional support for self-directed learning in higher education are warranted.

The association of faculty's teaching philosophy and teaching behaviour, and critical thinking and self- direction in learning

The intent in this study was to investigate in what ways teachers· beliefs about education and teaching are expressed in the specific teaching behaviours they employ, and whether teaching behaviours, as perceived by their students, are correlated with students· critical thinking and self-directed learning. To this end the relationships studied were: among faCUlty members· philosophy of teaching, locus of control orientation, psychological type, and observed teaching behaviour; and among students· psychological type, perceptions of teaching behaviour, self-directed learning readiness, and critical thinking. The overall purpose of the study was to investigate whether the implicit goals of higher education, critical thinking and self-direction, were actually accounted for in the university classroom. The research was set within the context of path-goal theory, adapted from the leadership literature. Within this framework, Mezirow·s work on transformative learning, including the influences of Habermas· writings, was integrated to develop a theoretical perspective upon which to base the research methodology. Both qualitative and quantitative methodologies were incorporated. Four faCUlty and a total of 142 students participated in the study. Philosophy of teaching was described through faCUlty interviews and completion of a repertory grid. Faculty completed a descriptive locus of control scale, and a psychological type test. Observations of their teaching behaviour were conducted. Students completed a Teaching Behaviour Assessment Scale, the Self-Directed Learning Readiness Scale, a psychological type test, and the Watson-Glaser Critical Thinking Appraisal. A small sample of students were interviewed. Follow-up discussions with faculty were used to validate the interview, observation, teaching behaviour, and repertory grid data. Results indicated that some discrepancies existed between faculty's espoused philosophy of teaching and their observed teaching behaviour. Instructors' teaching behaviour, however, was a function of their personal theory of practice. Relationships were found between perceived teaching behaviour and students· self-directed learning and critical thinking, but these varied across situations, as would be predicted from path-goal theory. Psychological type of students and instructor also accounted for some of the variability in the relationships studied. Student psychological type could be shown as a partial predictor of self-directed learning readiness. The results were discussed in terms of theory development and implications for further research and practice.

Thermodynamic properties and Debye-Waller factor of fee materials

We have calculated the equation of state and the various thermodynamic properties of monatomic fcc crystals by minimizing the Helmholtz free energy derived in the high temperature limit for the quasiharmonic theory, QH, and the lowest-order (cubic and quartic), 'A2, anharmonic terms of the perturbation theory, PT. The total energy in each case is obtained by adding the static energy. The calculation of the thermal properties was carried out for a nearest-neighbour central-force model of the fcc lattice by means of the appropriate thermodynamic relations. We have calculated the lattice constant, the thermal expansion, the coefficient of volume expansion, the specific heat at constant volume and at constant pressure, the isothermal and adiabatic bulk moduli, and the Griineisen parameter, for the rare-gas solids Kr and Xe, and gold. Morse potential and modified Morse potential were each used to represent the atomic interaction for the three fcc materials. For most of the calculated thermodynamic properties from the QH theory, the results for Kr and Xe with the modified Morse potential show an improvement over the results for the Morse potential when compared with the experimental data. However, the results of the 'A 2 equation of state with the modified Morse potential are in good agreement with experiment only in the case of the specific heat at constant volume and at constant pressure. For Au we have calculated the lattice contribution from the QH and 'A 2 PT and the electronic contribution to the thermal properties. The electronic contribution was taken into account by using the free electron model. The results of the thermodynamic properties calculated with the modified Morse potential were similar to those obtained with the Morse potential. U sing the minimized equation of state we also calculated the Mossbauer recoilless fraction for Kr and Xe and the Debye-Waller factor (DWF) for Pb, AI, eu, Ag, and Au. The Mossbauer recoilless fraction was obtained for the above two potentials and Lennard-Jones potential. The L-J potential gives the best agreement with experiment for Kr. No experimental data exists for Xe. At low temperature the calculated DWF results for Pb, AI, and eu show a good agreement with experimental values, but at high temperature the experimental DWF results increase very rapidly. For Ag the computed values were below the expected results at all temperatures. The DWF results of the modified Morse potential for Pb, AI, eu and Ag were slightly better than those of the Morse potential. In the case of Au the calculated values were in poor agreement with experimental results. We have calculated the quasiharmonic phonon dispersion curves for Kr, Xe, eu, Ag, and Au. The calculated and experimental results of the frequencies agree quite well for all the materials except for Au where the longitudinal modes show serious discrepancies with the experimental results. In addition, the two lowest-order anharmonic contributions to the phonon frequency were derived using the Green's function method. The A 2 phonon dispersion curves have been calculated only for eu, and the results were similar to those of the QH dispersion curves. Finally, an expression for the Griineisen parameter "( has been derived from the anharmonic frequencies, and calculated for these materials. The "( results are comparable with those obtained from the thermodynamic definition.

Gas chromatographic electron capture negative ionization mass spectrometric (GC/ECNI/MS) determination of unique fluorinated compounds in the sediments of Lake Ontario and the effect of high-boiling alcohols (as injection solvents) on chromatographic behaviour of polycyclic aromatic hydrocarbons in gas chromatography

Part I - Fluorinated Compounds A method has been developed for the extraction, concentration, and determination of two unique fluorinated compounds from the sediments of Lake Ontario. These compounds originated from a common industrial landfill, and have been carried to Lake Ontario by the Niagara River. Sediment samples from the Mississauga basin of Lake Ontario have been evaluated for these compounds and a depositional trend was established. The sediments were extracted by accelerated solvent extraction (ASE) and then underwent clean-up, fractionation, solvent exchange, and were concentrated by reduction under nitrogen gas. The concentrated extracts were analyzed by gas chromatography - electron capture negative ionization - mass spectrometry. The depositional profile determined here is reflective of the operation of the landfill and shows that these compounds are still found at concentrations well above background levels. These increased levels have been attributed to physical disturbances of previously deposited contaminated sediments, and probable continued leaching from the dumpsite. Part II - Polycyclic Aromatic Hydrocarbons Gas chromatography/mass spectrometry is the most common method for the determination of polycyclic aromatic hydrocarbons (PAHs) from various matrices. Mass discrimination of high-boiling compounds in gas chromatographic methods is well known. The use of high-boiling injection solvents shows substantial increase in the response of late-eluting peaks. These solvents have an increased efficiently in the transfer of solutes from the injector to the analytical column. The effect of I-butanol, I-pentanol, cyclopentanol, I-hexanol, toluene and n-octane, as injection solvents, was studied. Higher-boiling solvents yield increased response for all PAHs. I -Hexanol is the best solvent, in terms of P AH response, but in this solvent P AHs were more susceptible to chromatographic problems such as peak splitting and tailing. Toluene was found to be the most forgiving solvent in terms of peak symmetry and response. It offered the smallest discrepancies in response, and symmetry over a wide range of initial column temperatures.

Forgiveness in Two Minds: Understanding Forgiveness Through Dual-Process Theory

In this thesis, I examined the relevance of dual-process theory to understanding forgiveness. Specifically, I argued that the internal conflict experienced by laypersons when forgiving (or finding themselves unable to forgive) and the discrepancies between existing definitions of forgiveness can currently be best understood through the lens of dual-process theory. Dual-process theory holds that individuals engage in two broad forms of mental processing corresponding to two systems, here referred to as System 1 and System 2. System 1 processing is automatic, unconscious, and operates through learned associations and heuristics. System 2 processing is effortful, conscious, and operates through rule-based and hypothetical thinking. Different definitions of forgiveness amongst both lay persons and scholars may reflect different processes within each system. Further, lay experiences with internal conflict concerning forgiveness may frequently result from processes within each system leading to different cognitive, affective, and behavioural responses. The study conducted for this thesis tested the hypotheses that processing within System 1 can directly affect one's likelihood to forgive, and that this effect is moderated by System 2 processing. I used subliminal conditioning to manipulate System 1 processing by creating positive or negative conditioned attitudes towards a hypothetical transgressor. I used working memory load (WML) to inhibit System 2 processing amongst half of the participants. The conditioning phase of the study failed and so no conclusions could be drawn regarding the roles of System 1 and System 2 in forgiveness. The implications of dual-process theory for forgiveness research and clinical practice, and directions for future research are discussed.