Prediction of stress-strain behaviors in steels using an integrated constitutive, FEM and ANN model

Austenitic steels with a carbon content of 0.0037 to 0.79 wt% C are torsion tested and modeled using a physically based constitutive model and an Integrated Phenomenological and Artificial neural Network (IPANN) model. The prediction of both the constitutive and IPANN models on steel 0.017 wt% C is then evaluated using a finite element (FEM) code ABAQUS with different reduction in the thickness after rolling through one roll stand. It is found that during the rolling process, the prediction accuracy of the reaction force from FEM simulation for both constitutive and IPANN models depends on the strain achieved (average reduction in thickness). By integrating FEM into IPANN model and introducing the product of strain and stress as an input of the ANN model, the accuracy of this integrated FEM and IPANN model is higher than either the constitutive or IPANN model.

Prediction intention to quit in the call centre industry: does the retail model fit?

Purpose – Models of workplace turnover are rarely assessed in contexts other than that in which they were developed. This reduces their generalizability and their usefulness in providing managers with guidance as to what they might do to reduce workers intentions to quit. The purpose of this study is to test a model derived from a study of shop floor retail salespeople in the call centre environment.

Design/methodology/approach – A questionnaire measuring the variables in the model was completed by 126 call centre representatives recruited from 11 call centres in Melbourne, Australia.

Findings – Although the model was supported, the interactions among the variables differed. In particular, stressors played a bigger, albeit indirect, role in the intention to quit.

Practical implications – Call centre managers need to consider carefully the aspects of the work environment that may be stressful. If appropriately addressed, turnover may be reduced, and productivity increased.

Originality/value – This paper demonstrates that the model of turnover derived from shop floor salespeople is generally robust in the call centre setting. It provides management of call centres with some guidance as to the factors associated with turnover and areas that can be addressed to reduce it.

A retail supply chain risk assessment conceptual model

Supply chains are increasingly relying on information and communications technologies and in particular electronic commerce to facilitate transactions between supply chain partners. The adoption of these enabling technologies brings several enhancements to the conduct of business including gains in efficiency. However there are also drawbacks inherent in these technologies that include threats that are imposed on businesses that use them. This paper presents a study on retail supply chains and the risks and vulnerabilities that cooperating supply chain partners are exposed to when adopting these technologies. In particular, the paper discusses the various threats and vulnerabilities of retail supply and presents a conceptual model of such risks.

Analytical model of pass-by-pass strain in rod (or bar) rolling and its applications to prediction of austenite grain size

Rod rolling is a process where the deformation state of the workpiece between the work rolls is quite different from the strip rolling process. However, in most microstructure evolution models, the simple area strains (natural logarithm of the area reduction ratio) multiplied by a constant have been used to compute pass-by-pass evolution of austenite grain size (AGS) in rod (or bar) rolling, without any verification. The strains at a given pass play a crucial role in determining the recrystallization behavior (static or dynamic). In this study, an analytical model that calculates the pass-by-pass strain and strain rate in rod rolling has been developed and verified by conducting four-pass (oval–round) bar and plate rolling experiments. Numerical simulations have then been carried out for the four-pass rolling sequence using the area strain model and the new analytical model, focusing on the effect of the method for calculating the strain on the recrystallization behavior and evolution of AGS. The AGS predicted was compared with those obtained from hot torsion tests. It is shown that the analytical model developed in this study is more appropriate in the analysis of bar (or rod) rolling. It was found that the recrystallization behavior and evolution of AGS during this process were influenced significantly by the calculation method for the deformation parameters (strain and strain rate). The pass-by-pass strain obtained from the simple area strain model is inadequate to be used as an input to the equations for recrystallization and AGS evolution under these rolling conditions.

Validation of model-based estimates (synthetic estimates) of the prevalence of risk factors for coronary heart disease for wards in England

Several sets of model-based estimates (synthetic estimates) of the prevalence of risk factors for coronary heart disease for small areas in England have been developed. These have been used in policy documents to indicate which areas are in need of intervention. In general, these models have not been subjected to validity assessment. This paper describes a validity assessment of 16 sets of synthetic estimates, by comparison of the models with national, regional and local survey-based estimates, and local mortality rate estimates. Model-based estimates of the prevalence of smoking, low fruit and vegetable consumption, obesity, hypertension and raised cholesterol are found to be valid.

Risk allocation in public-private partnership projects : an innovative model with an intelligent approach

Both the increasing private participation in public projects and the critical importance of appropriate risk allocation to the success of Public-private partnership (PPP) projects justify specific research on how to establish effective risk allocation strategies in PPP projects. Partner’s risk management capability is currently the main concern to risk allocation in PPP projects. Following the transaction cost economics, it is argued that factors such as partner’s commitment and risk management structure should be considered simultaneously in order to develop effective risk allocation strategies. Based on the holistic capability-commitment governance-driven view, this paper proposed a model for generating an optimal risk allocation strategy in PPP projects. The model is demonstrated and described. An artificial intelligent technique integrated with fuzzy logic for model testing and validation is then introduced and justified. The innovative model is expected to provide a logical and complete understanding of the risk allocation strategy selection process, and to provide stakeholders with a richer framework than previously existing ones to guide their decision-making on risk allocation strategies.

Dancing with death : the grey area between suicide related behavior, indifference and risk behaviors of heroin users

Suicide-related behavior (SRB) among heroin users is a complex and multifaceted continuum, including such fringe areas as indifference and "risky" behavior. The article investigates the nuances and intersections of SRB, using qualitative semi-structured interviews with 60 regular heroin users recruited primarily from syringe programs in Geelong, Australia. Twenty-eight percent of interviewees reported a previous suicide attempt and 45% reported serious consideration of it. Types of SRB reported included: Suicide attempts, instrumental suicide-related behaviors, suicidal ideation, indifference and risk-taking thoughts and behaviors. Heroin users engage in much behavior which inhabits a grey area of SRB. The use of a nomenclature which addresses the elements of lethality and intent improves the ability of research to properly define and categorize SRB in drug-using populations. But the categories should not be overinclusive; indifferent attitudes towards death and risk-taking behaviors can sometimes be a functional response to the risk environment of heroin users.

Obesity is associated with previous suicide attempts in bipolar disorder

Objective: There is a paucity of data about risk factors for suicide attempts in bipolar disorder. The aim of this study is to examine the association between suicide attempts and obesity in people with bipolar disorder.

Methods: Two hundred fifty-five DSM-IV out-patients with bipolar disorder were consecutively recruited from the Bipolar Disorder Program at Hospital das Clínicas de Porto Alegre and the University Hospital at the Universidade Federal de Santa Maria, Brazil. Diagnosis and clinical variables were assessed with Structured Clinical Interview for DSM-IV-axis I (SCID I) and Program structured protocol. History of suicide attempts was obtained from multiple information sources including patients, relatives and review of medical records. Patients with body mass index (BMI) ≥ 30 were classified as obese.

Results: Over 30% of the sample was obese and over 50% had a history of suicide attempt. In the multivariate model, obese patients were nearly twice (OR = 1.97, 95% CI: 1.06–3.69, p = 0.03) as likely to have a history of suicide attempt(s).

Conclusion: Our results emphasise the relevance of obesity as an associated factor of suicide attempts in bipolar disorder. Obesity may be seen as correlate of severity and as such, must be considered in the comprehensive management of bipolar patients.