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Laminar morphology of high density polyethylene (HDPE)/polyamide-6 (PA-6) blends was obtained, for the first time, in a co-rotating twin screw extruder. The morphology analysis in the interior of the adapter, which connects the extruder with a slit die, revealed that, under specific processing conditions, it is possible to produce layers of PA-6 in the end of the screw zone of the extruder. These layers were visible at very low magnification (6.7X). It was also observed that a high adapter converging angle (70°) produced breakup of the layers, due to the high elongational and shear flow. / The micrographs of the extruded final products showed distributed layers across the sample thickness are along the flow direction. The effect of design variables such as adapter angle and die gap on the final product morphology was studied. The effect of processing variables, including temperature profile, feed rate, and screw speed, were evaluated. speed, were evaluated. (Abstract shortened by UMI.)

Injection molding is a high rate production process for manufacturing plastic parts. There is often a conflict between good appearance and short cycle time. Injection molded parts can show several types of surface defect. It is believed that wall slip may be associated with some types of defect, because wall slip can modify the distributions of velocity, wall shear stress, pressure and heat flux. The work described here involves an experimental study of the occurrence of flow marks during injection molding of linear polyethylene, and the possible relationship between these defects and wall slip. It also involves the investigation of the feasibility of incorporating wall slip models in the 2.5D computer simulation of the injection molding process.

This work seeks to explore and evaluate some of the evolving technological tools available for instruction and learning in the field of education. An assessment is made of the value and effectiveness of using new technologies, and associated educational theories on existing and emergent technologies are considered. A study is made of Second Life, an online virtual reality simulator, and its educational potentials are considered along with those of video-gaming and other emerging learning tools and spaces. These are the foundations for the discussion about the potentials of integrating new technologies into teaching, learning, and education as a whole. / Ce travail engage à explorer et analyser certains des instrumentstechnologiques disponibles pour l’instruction et l’apprentissage dans le domaine del’éducation. L’utilisation des nouvelles technologies dans le domaine sont mis enrevue, et les théories associées aux outils existant et émergeant sont évalués. Uneétude est faite de Second Life, un logiciel simulant la réalité virtuelle, et sespotentiels éducatifs sont considérés avec ceux des jeux vidéo et d’autres nouveauxgenres d’apprentissage. Ceci fait la base de la discussion concernant les potentielsde l’intégration des nouvelles technologies dans l’enseignement, l’apprentissage, etl'éducation dans son ensemble.

<p> Information security is a complex issue, which is very critical for success of modern businesses. It can be implemented with the help of well-tested global standards and best practices. However, it has been studied that the human aspects of information security compliance pose significant challenge to its practitioners. There has been significant interest in the recent past on how human compliance to information security policy can be achieved in an organization. Various models have been proposed by these researchers. However, there are very few models that have tried to link human commitment attributes with information security governance of an organization. The research problem of this study was to identify the security controls and mechanisms to govern information security effectively. The proposed model was based on agency theory and comprises a relationship between human commitment variables (ethics, integrity and trust) with security governance variables (structural, relational and process) referred as systemic variables in the research. The resulting correlation is further related with governance objectives (goal congruence and reducing information asymmetry) to hypothesize an effective information security in an organization. The research model proposed was tested employing confirmatory factor analysis (CFA) and structural equation modeling (SEM). There were four models tested in this research. The first model (initial measurement model) comprised human variables linked with relational and the systemic variables linked with goal congruence and information asymmetry. This model could not get through the CFA tests. A modified model comprising human and systemic attributes related with goal congruence and information asymmetry, separately, was taken forward to SEM. This model returned low model fitment scores and hence two alternate models were tested. In the first alternative, the human attributes were related with goal congruence and systemic attributes were linked with information asymmetry. In the second alternative, the relationships of the first alternatives were retained and two alternate relationships were introduced - integrity was linked with information asymmetry and structural was linked with goal congruence. Both models are very close to good model fitment scores. However, the second alternative returned better results and hence, was chosen as the final outcome of the research. The model reflects that human attributes and systemic attributes are fairly independent in an effective information security framework, and drive goal congruence and information asymmetry, respectively. However, integrity is an important human commitment for ensuring information asymmetry and the right organizational structure and roles are important for ensuring goal congruence.</p>

An optical technique for monitoring the solidification of thermoplastics in an injection moulding machine was implemented. The technique uses a He-Ne laser that illuminates the mould cavity, and a photomultiplier to measure the intensity of reflected light during the moulding cycle. Data from the sensor allows tracking the injection moulding cycle development. The measured light intensity is mainly influenced by refraction and reflection phenomena at the melt-solid interfaces during solidification. Reflection occurs primarily from the opposite mould wall but the reflection intensity is a complex composite of reflective scattering and refraction from crystallites, the mould wall and as many as six interfaces. The scattering caused by the opposite mould wall roughness also affects the light intensity. Plots of reflection intensity during the injection moulding cycle obtained for the three materials tested show similar patterns. Polystyrene, polypropylene and high-density polyethylene resins were used. The higher scattering power of semi-crystalline polyethylene and polypropylene reduces the reflection intensity values compared to the polystyrene plots. Further experimental and analytical work is required to use this technique for process control purposes.

The nonlinear viscoelastic properties of a series of blends of linear polyethylene were studied using the McGill sliding plate rheometer. A more reliable and sensitive shear stress transducer for this rheometer was designed, built and used in this work. The molecular weight dependence of a variety of nonlinear viscoelastic properties was investigated. It was determined that, as with steady state properties, the sensitivity of such properties to molecular weight diminishes with increasing shear rate. The behavior of these materials in large amplitude oscillatory shear (LAOS) was also studied. By using harmonic analysis, the frequency content of the nonlinear stress response to the sinusoidal strain was studied as a function of molecular weight, strain amplitude and frequency. The predictive abilities of the Wagner model in LAOS, exponential shear, start-up and cessation of steady shear and interrupted shear, at high shear rates were evaluated. Qualitative trends were well predicted by the model for a variety of sigmoidal and exponential damping function forms. For the first time, it has been shown that Wagner model predictions for molten thermoplastics are insensitive to the damping function form. The damping functions in simple shear and planar extension were obtained for a branched low density polyethylene (LDPE). Simple shear is similar to planar extension in a rotated reference frame and thus the two flows should have similar damping functions. It was found that the damping functions that fitted these two flows are, in fact, quite different. Thus we have shown that the contribution of kinematics cannot be simply described.

<p> The purpose of this mixed methods study was to assess the perceptions of classroom teachers, administrators and professional support staff in one Midwest school district regarding the usefulness and effectiveness of the iPad device as an instructional and support tool within the classroom. The need to address classroom teacher, administrator and professional support staff perceptions was crucial as the researched school district approved the move to one-to-one student iPad implementation. Quantitative and qualitative data were collected from three role-specific online surveys containing Likert scale and open-ended questions. Qualitative data were collected during face-to-face interviews. </p><p> The quantitative data suggested classroom teachers did not perceive the positive effects of the iPad on classroom instruction while professional support staff did perceive the positive effects of the iPad to support classroom instruction. Overlapping themes emerged from the qualitative data sources and the most prominent themes noted: iPad as a job specific tool; iPad as a student tool; and professional development in learning how to utilize the iPad in an educational setting. Additional outlier theme responses included: time, specifically the lack of time in general and the need for time to use the device, and 21st century skills, specifically the absence of responses connecting the iPad to 21st century skills. The researcher presented results from the iPad pilot exit survey secondary data from the study school district. Due to the rapid evolution of technology the need to assess perceptions in an educational setting will continue. The results of this study add to the growing amount of research on mobile technology and educators' perceptions regarding technology implementation. </p>

The variability of thermal expansion coefficients during the molding of plastics causes the development of frozen thermal stresses in the molded parts. Also, the distribution of thermal expansion coefficients of the material in the molded part plays an important role in controlling shrinkage and warpage. In turn, the distribution of linear thermal expansion coefficients (LTECs) depends on the distributions of crystallinity and orientation in the part. In the case of fibre reinforced polymers, the distributions of fibre concentration and orientation are also important. / In this project, a model has been proposed for estimating the LTEC of fibre reinforced plastics as a function of crystallinity, matrix orientation, and fibre concentration and orientation. Also, extensive data have been obtained regarding the LTEC of polypropylene with and without fibre reinforcement. Extruded pellets and injection molded parts were considered. Model predictions have been compared with experimental data.

This study involves the use of an inline rheometer (ILR) for process control. The ILR is a melt viscosity sensor that is mounted directly in the main process stream. This type of installation minimizes the measurement delay time, which is important for sensors used in process control applications. / The ILR was used for the closed loop control of product viscosity of post-consumer recycled high density polyethylene crosslinking in a twin screw extruder. The manipulated variable is the feed rate of crosslinking agent. Internal model control, Dahlin control, and minimum variance control algorithms were successfully implemented.