Fracture Toughness of Phenol Formaldehyde Composites: Pilot Study

A commercial phenol formaldehyde based resole thermosetting resin (Hexion “J2027L”) was filled with ceramic-based fillers (Envirospheres “slg”) to increase its strength and fracture toughness. By testing viscosity, strength, and fracture toughness at a range of filler addition levels, the optimal addition level of SLG was able to be determined in terms of workability, cost, and performance. It was found that the fracture toughness of this resin could be significantly increased through the addition of the slg filler. The results show that composite with 20% by weight of the slg produces the best balance between ease of casting and impact performance.     

Influence of Social Networks on Latent Choice of Electric Cars: A Mixed Logit Specification Using Experimental Design Data

Electric cars can potentially make a substantial contribution to the reduction of pollution and noise. The size of this contribution depends on the acceptance of this new technology in the market. This paper reports on the design and results of an elaborate stated choice experiment to investigate the effects of vehicle attributes, contextual and social network attributes on the latent demand for electric cars. The study contributes to the existing literature primarily by explicitly modelling the effects of different elements of social networks on the latent demand for electric cars. Moreover, the number of attributes included in the study design exceeds the typical number of attributes used in previous research, making the model more sensitive to a larger spectrum of variables. Two different mixed logit models are estimated: one with random parameters for vehicle attributes and contextual attributes and fixed effects for the social network attributes; one with random effects for social network attributes and fixed effects for the remaining attributes. Results indicate substantive differences between these two models in terms of the shape of utility curves. Overall, vehicle attributes are most important in the choice of electric cars, followed by social influence attributes. The effects of social network are relatively small.     

Review of Clinical Assessment before Trial.

Reviews the book, Clinical Assessment before Trial by C. D. Webster, R. J. Menzies, and M. A. Jackson (1982). The stated scope and purpose of this text are most ambitious. Webster, Menzies, and Jackson propose to answer seven or eight major questions for three specific purposes. They hope to encourage a compassionate interest in the mentally disordered offender, provide an academic study of the actions of clinicians, and give a sociological perspective on the interconnection of medicine and law. They have obviously given considerable thought of how the format of the book might assist in accomplishing their goals. They offer chapters addressed to the questions they ask and provide a walk-through of the issues using two hypothetical cases as examples. It is worth pointing out that the authors provide excellent references to Canadian forensic agencies and some corresponding data about these services. The bibliography is also very useful for Canadian students (and practitioners) who wish access to more detailed material than the text is able to provide. On the whole, the reader is provided with a reasonable academic introduction to clinical assessment before trial. The book fails to the extent that the authors appear to have gambled about how to use the space provided. In the end, the book has a resulting weakness. The main section does not have the space needed to become a major text. And yet the one-third of the book that is Appendices could just as well have been published in a regular journal. Better judgment would have provided the authors with more room to address the many important points dealt with in the main section fully. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Untersuchungen zum Zusammenhang von Gefügeaufbau und Zerfallsverhalten hämatitischer Stückerze bei der Reduktion

Der Gefügeaufbau bestimmt das Zerfallsverhalten eines hämatitischen Stückerzes während der Reduktion. Erze mit ähnlichen Strukturen weisen ähnliches Zerfallsverhalten auf. Werden die mineralogischen Befunde durch Vergleichsbilder normiert und in ein ?Erzgefüge-Schaubild” eingetragen, lassen sich die Erze mit Hilfe ihrer Gefügemerkmale in gute und schlechte Qualitäten unterteilen. Vorhersagen über das Zerfallsverhalten unbekannter Erze ergeben sich aus der Lage im ?Erzgefüge-Schaubild” und durch einen Vergleich mit Erzen, deren Reduktionsverhalten bekannt ist.     

New Algorithms for Polynomial J-Spectral Factorization

In this paper new algorithms are developed for J-spectral factorization of polynomial matrices. These algorithms are based on the calculus of two-variable polynomial matrices and associated quadratic differential forms, and share the common feature that the problem is lifted from the original one-variable polynomial context to a two-variable polynomial context. The problem of polynomial J-spectral factorization is thus reduced to a problem of factoring a constant matrix obtained from the coefficient matrices of the polynomial matrix to be factored. In the second part of the paper, we specifically address the problem of computing polynomial J-spectral factors in the context of H _∞ control. For this, we propose an algorithm that uses the notion of a Pick matrix associated with a given two-variable polynomial matrix. Date received: January 1, 1998. Date revised: October 15, 1998.     

Structure in cokes from coals of different rank

A range of bituminous coals has been carbonized to 1273 K. Polished surfaces of the solid products, carbons or cokes, are examined for optical texture by optical microscopy. Fracture surfaces of the carbons are examined by scanning electron microscopy (SEM). The carbon from the lowest rank coal (NCB Code No. 702) is isotropic and fracture surfaces are featureless. Carbons from coals of ranks 602, 502 are optically isotropic but fracture surfaces are granular (size 0.1–0.2 μm), indicating small growth units of mesophase. In the carbon/coke from a 401 coal, the anisotropic optical texture and grain size are both ≈0.5–10 μm diameter. Coke from a coking coal (301a, 301b) has a layered structure extending in units of at least 20 μm diameter with sub-structures ~ 1.5 μm within the layers, indicating perhaps that the bedding anisotropy of these coals is not totally lost in the fluid phase of carbonization. The carbons from the higher rank coals have the bedding anisotropy of the parent coal. The combined techniques of optical microscopy and SEM (both before and after etching of the fracture surfaces of coke in chromic acid solution) reveal useful detail of structure in carbons/cokes and of the mechanism of carbonization of coking coals.     

Interpenetrating polymer networks from polyurethanes and poly(methyl acrylate)

Simultaneous two-component interpenetrating polymer networks (IPNs) of polyurethane (PU)–poly(methyl acrylate) (PMA) were prepared, as well as the corresponding pseudo-IPNs. A comparison was made between the full IPNs, pseudo-IPNs, and the respective homopolymers. Their ultimate mechanical properties were obtained and the dynamic glass transition temperatures (T_g's) were found using a thermomechanical analyzer. At all compositions, a single T_g(except 50–50 wt %) was found.     

Occupational stress in Canadian universities: A national survey.

Stress surveys in U.K. and Australian universities demonstrated high occupational stress levels among faculty. This study investigated whether the same occupational stressors and stress outcomes applied at Canadian universities. Randomly selected staff (n = 1440) from 56 universities completed a Web-based questionnaire. The response rate 27%, was similar to those in the U.K. and Australian studies, as were most of the results. With respect to strain, 13% of the respondents reported high psychological distress and 22% reported elevated physical health symptoms. Less secure employment status and work-life imbalance strongly predicted job dissatisfaction; work-life imbalance strongly predicted increased psychological distress. Overall study participants were satisfied with their jobs and emotionally committed to their institutions. These results warrant consideration of contemporary academic work by both academic staff associations and university administrations with respect to the implementation of changes in policies and procedures that might lead to reductions in work-related stress and strain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)