Impact of PP Impurities on ABS Tensile Properties: Computational Mechanical Modelling Aspects

Recycling of plastics is hindered by their important variety and strong incompatibility. However, sorting technologies bear costs and meet limits. Very high purities (<2 wt%) are difficult to reach. Yet, such rates may be detrimental to functional properties. In this work, an ABS matrix (major plastic in Waste of Electrical and Electronic Equipments) was filled with 4 wt% of PP to mimic impurities in ABS after recycling. PP-g-MA was introduced in the blend to improve the compatibility. A finite element model was developed from the mechanical behavior of each component. ABS and PP were individually characterized from tensile tests instrumented with photomechanics and their behaviors were modelled through a set of numerical parameters (elasto-visco-plasticity with a Gurson’s criterion behavior). Comparison between the determinist model results and the experimental data (strength, volumetric variation) shows that this type of modelling could be a predictive tool in order to anticipate composite mechanical properties and to understand micromechanisms of deformation (damage, cavitation). The main result is that PP introduced at 4 wt% into ABS does not alter the static mechanical properties despite polymers incompatibility. The addition of PP-g-MA modifies the local properties and possibly conduct to a premature breakage of the polymer blend.

The Validity of Prison Classification: An Introduction to Practical Considerations and Research Issues

Many prison classification systems include risk assessment instruments designed to assign individuals to institutions varying in security features or to levels of supervision differing in staffing patterns and the extent of inmate privileges. Decision criteria that make up classification instruments are selected to measure inmate attributes as information that predicts the occurrence or rates of prison disciplinary problems. The present article is an introduction to research designs and methods for use in the validation of classification instruments. Hypothetical validity findings are presented to demonstrate their critical role in the development of a classification system. Finally, it is concluded that validation research, whether for management or scientific purposes, is optimally conducted in a program of research designed to evaluate the risk assessment instrument in the context of other components of the classification system and environmental variables that influence validity criterion behavior.

Alcohol, Drug Use, and Delinquent and Criminal Behaviors among Male Adolescents and Young Adults

This paper examines the relationship between reported delinquent and criminal behavior and drug use patterns among male adolescents and young men in the United States. In an effort to refine prior analyses on the subject, pattern of alcohol use is viewed as a variable worth considering in conjunction with heroin and/or cocaine use patterns. The analysis indicates that the drug patterns relate differentially to the selected indicators of delinquent and criminal behavior and that generalizations about these relationships depend on the nature of the criterion behavior and on ethnic group differences. It is concluded that the clearly excessive criminality of hard drug users does not make hard drug use a powerful predictor of criminality in the population as a whole, since a relative few of all criminal acts are committed by hard drug users and that pattern of alcohol use is a salient variable.

Does Sincerity Matter? An Empirical Test

I conducted 2 experiments to test the hypothesis that participants who are given more (vs. less) sincere reinforcement will achieve criterion behavior sooner or more completely, and also tested for the Greenspoon effect. In each experiment, assistants' biases were measured and they were then asked to reinforce participants' responses under conditions where that reinforcement was either congruent or incongruent with the identified biases. Assistants' effectiveness under these 2 conditions was determined by measuring the shift in participants' responses from baseline values. In Experiment 1, 20 assistants reinforced designated responses by 40 participants to a 40-item questionnaire. Results supported a sincerity effect but not the Greenspoon effect. The results of Experiment 2 were nonsignificant, which I attribute to the use of a design resulting in less assistant–participant communication.

Head Position Identification

A binaural recording of traffic sounds that reached an artificial head oriented in five different positions was presented to five subjects, each of whom responded under four different criteria. The results showed that it is possible to examine the ability of listeners to localize sound while listening through earphones and that the criterion adopted by an individual listener is independent of his performance. For the experimental conditions used, the Type II ROC curve generated by manipulating criterion behavior was linear and consistent with a guessing model. Further experiments involving different degrees of stimulus degradation suggested a partial explanation for this finding and illustrated the various types of monaural and binaural cues used by normal and hearing-impaired listeners to localize complex sounds.