Modeling of advanced high strength steels with the realistic microstructure–strength relationships

The objective of the work is to consider the first-order effects of the realistic microstructure morphology in the macroscale modeling of the multiphase Advanced High Strength Steels (AHSS). Instead of using constitutive equations at macroscale, the strength–microstructure relationship is studied in the forms of micromechanical and multiscale models that do not make considerable simplifications with regard to the microscale geometry and topology. The trade-off between the higher computational time and the higher accuracy has been offset with a stochastic approach in the construction of the microscale models. The multiphase composite effects of AHSS microstructure is considered in realistic microstructural models that are stochastically built from AHSS micrographs. Computational homogenization routines are used to couple micro and macroscale and resultant stress–strain relations are compared for models built with the simplified and idealized geometries of the microstructure. The results from this study show that using a realistic representation of the microstructure, either for DP or TRIP steel, could improve the accuracy of the predicted stress and strain distribution. The resultant globally averaged effective stress and strain fields from realistic microstructure model were able to accurately capture the onset of the plastic instability in the DP steel. It is shown that the macroscale mechanical behavior is directly affected by the level of complexities in the microscale models. Therefore, greater accuracy could be achieved if these stochastic realistic microstructures are used at the microscale models.

Characterising material and process variation effects on springback robustness for a semi-cylindrical sheet metal forming process

Variation in the incoming sheet material and fluctuations in the press setup is unavoidable in many stamping plants. The effect of these variations can have a large influence on the quality of the final stamping, in particular, unpredictable springback of the sheet when the tooling is removed. While stochastic simulation techniques have been developed to simulate this problem, there has been little research that connects the influence of the noise sources to springback. This paper characterises the effect of material and process variation on the robustness of springback for a semi-cylindrical channel forming operation, which shares a similar cross-section profile as many automotive structural components. The study was conducted using the specialised sheet metal forming package AutoForm^TM Sigma, for which a series of stochastic simulations were performed with each of the noise sources incrementally introduced. The effective stress and effective strain scatter in a critical location of the part was examined and a response window, which indicates the respective process robustness, was defined. The incremental introduction of the noise sources allows the change in size of the stressstrain response window to be tracked. The results showed that changes to process variation parameters, such as BHP and friction coefficient, directly affect the strain component of the stressstrain response window by altering the magnitude of external work applied to forming system. Material variation, on the other hand, directly affected the stress component of the response window. A relationship between the effective stressstrain response window and the variation in springback was also established.

Path independent limiting criteria in sheet metal forming

The Forming Limit Diagram (FLD) is a conventional failure diagram to estimate necking limits of sheet metal for proportional loading conditions. Previous studies reveal that the FLD is not suitable for predicting the influence of nonlinear strain paths. This paper presents methodical comparison among all common available strain path independent strain/stress based limiting criteria. All the strain path independent strain based limiting criteria (Traditional Failure Diagram (TFD), Extended Forming Limit Diagram (XFLD), Extended Stress Ratio Based Forming Limit Diagram (ESRFLD), and Polar Effective Plastic StrainDiagram (PEPSD)) and stress based limiting criteria (Traditional Stress based Failure Diagram (TFSD), Stress Based Forming Limit Diagram (FLSD), Stress Ratio and Stress Based Forming Limit Diagram (SRFLSD), Extended Stress Based Forming Limit Diagram (XFLSD), and Polar Effective Stress Diagram (PESSD)) are approximately path-independent for smaller amount of pre-straining and path dependent for large pre-straining conditions. From advance image correlation technique precisely determination of local strains near necked area is possible today. However direct determination of local stresses near necked area is not possible. Therefore, local stresses and equivalent stress are determined by employing both yield criterion and strain-hardening law. Similarly equivalent strain is calculated by the use of yield criterion. Therefore, the choice of yield criterion has an impact on the results for TFD, XFLD, ESRFLD and PEPSD. However, selections of both yield criterion and strain-hardening law have substantial influence on the results for TFSD, FLSD, SRFLSD, XFLSD and PESSD. The inherent calculation error can be minimized by generation of experimental data for each material and then selection of representable yield criterion and strain-hardening law. Improvement of experimental techniques and generation of rigorous material data bank in various strain paths may help researchers to diagnose and resolve the issue. TFD, TFSD and XFLSD have inherent variables to take care the effect of through thickness stress, however rigorous experimental verification is needed before the field application.

Hydraulic performance of geosynthetic clay liners to sulfuric acid solutions

The ability of geosynthetic clay liners (GCLs) to contain acidic mining leachates is examined. The results of saturated hydraulic conductivity (k) of two GCLs permeated with sulfuric acid solutions (H2SO4) at 0.015M, 0.125M and 0.5M concentrations are reported. Also, the saturated k values of consolidated (35kPa) bentonite cakes made from sodium bentonite extracted from both GCLs were compared to a commonly used magnesium-sodium form bentonite. Chemical compatibility and effects of pre-hydration and effective stress were assessed as part of this study. Results indicated that an increased acid concentration (ionic strength) increased the k of all tested specimens. The ratio of the k0.5 values for non-prehydrated specimens permeated with 0.5M H2SO4 to the kw values for specimens permeated with deionized (DI) water (k0.5/kw) ranged from 10 to 110. Pre-hydration (50-140% water content) and increased effective stress (35-200kPa) improved the performance of GCLs (lower k). Strong correlations were observed between k and liquid limit and swell index parameters independent of pre-hydration and effective stress in this study. However, care should still be taken when using these correlations to evaluate hydraulic performance because the intrinsic micro-structure properties of bentonite, such as porosity, should also be considered. This work showed that, for example, high SI of bentonite does not translate necessarily to a better hydraulic performance of GCLs.

Is implementation of the 2013 Australian treatment guidelines for posttraumatic stress disorder cost-effective compared to current practice? A cost-utility analysis using QALYs and DALYs

To assess, from a health sector perspective, the incremental cost-effectiveness of three treatment recommendations in the most recent Australian Clinical Practice Guidelines for posttraumatic stress disorder (PTSD). The interventions assessed are trauma-focused cognitive behavioural therapy (TF-CBT) and selective serotonin reuptake inhibitors (SSRIs) for the treatment of PTSD in adults and TF-CBT in children, compared to current practice in Australia.

Governing the Stressed Self: teacher "health and well-being" and "effective schools"

In diverse arenas there is much discussion about the dangerousness of contemporary lifestyles, including the stressful nature of work. These stresses associated with contemporary lifestyles and work are dangerous in so far as they are conceived as placing at risk the emotional, physical and psychic health and well-being of large populations. In this paper we engage with debates about the stressful nature of teachers' work, and the ways in which teacher health and well-being are constructed as being central to the task of delivering more effective schools. In this article we are not so much concerned with the nature of teacher stress as an indication of individual physical, emotional or psychic health and well-being, as with understanding how it is that at this particular historical juncture the self can be so widely conceived in terms of stress. Moreover, what processes make it possible at this moment to link the success or otherwise of a massive institutional process of state-regulated schooling to the health and well-being of teachers and the management of this health and well-being by school managers? We argue that in a policy context that devolves various responsibilities to self-managing schools, the government of the stressed self emerges as an ethical concern for teachers and those who manage them (Foucault, The Use of Pleasure , New York, Pantheon, 1985). Our purpose is to problematise these processes so that responsibilities for delivering on the promise of effective schools might be differently framed and debated.

Additive effect of interferential therapyover pelvic floor exercise alone in the treatment of female urinary stress and urge incontinence: A randomized controlled trial

This pilot study attempted to examine the additional efficacy of interferential therapy in reducing the symptoms of urinary stress and urge incontinence. Twenty-four subjects were randomly allocated to the experimental group, which received interferential therapy plus pelvic floor exercises, or the control group, which received pelvic floor exercises only. Treatment was given three times a week for 4 weeks. Subjects were given urinary diaries to record urinary symptoms (including frequency of passing urine and number of times woken by desire to pass urine) for 5 days prior to and after treatment. Perineometer readings, pad weighing test and start/stop test were also performed in a physiotherapy clinic before and at completion of treatment regimes. Significant improvements were observed in all the outcome variables in the experimental group, but in only the perineometer readings in controls. When the changes from pre- to post-treatment were compared between the two groups, four of the dependent variables did not reach statistical significance. Power analysis indicated that the sample size for each group needed to be 70 for all results to be statistically significant. This study shows that interferential therapy plus pelvic floor exercise appears to be a more effective treatment modality than pelvic floor muscle strengthening exercise alone for incontinence, but a larger trial with longer followup is needed before definitive conclusions can be reached.

Evaluation of a stress management course in adult education centres in rural Australia

Objective: To investigate whether attending a six-week stress management course in a rural adult education centre is effective in reducing participants' levels of stress, anxiety and depression.

Design: Repeated measures design using self-report measures of stress, anxiety and depression at commencement and completion of a six-week stress management course, and six months post-completion follow up.

Setting and participants: One hundred and thirty-two adults (age range 18–73 years) living in a rural community who self-enrolled in the stress management course at adult education centres.

Intervention: The course consisted of six weekly group sessions. Each two-hour session conducted by mental health professionals, included teaching cognitive behavioural strategies targeted at reducing individual symptoms of stress.

Main outcome measures: Comparative analysis of pre- and post-test and six-month follow up on measures of stress (Stress Symptom Checklist), anxiety and depression (Hospital Anxiety and Depression Scale).

Results: Results indicated a significant reduction in stress symptoms (F(7,90) = 34.92, P < 0.001), anxiety and depression (F(3,95) = 87.92, P < 0.001) from course commencement to course completion. These improvements were sustained six months after course completion for stress symptoms (F(11,65) = 22.40, P < 0.001), anxiety and depression (F(5,73) = 41.78, P < 0.001).

Conclusion: Findings demonstrate the stress management course is an effective community intervention in a rural community. Challenges for future implementation of the program are discussed.

The UK perspective: a review of research on organisational stress management interventions

There are an increasing number of studies that have monitored the impact of Stress Management Interventions (SMls) and the results of these studies can play a vital role in informing the development of more effective, evidenced-based SMIs. In this paper, the authors have undertaken a review of United Kingdom (UK)-based research that has tested the impact of SMIs. Sixteen studies were examined and the results revealed that the vast majority of interventions were targeted at the individual employee, although there was a tendency for more recent research to focus on organisational level interventions. While all intervention levels were found to have some human and/or organisational benefits, strategies aimed at the individual level were less likely to result in longer-term benefits. An examination of the research methods used in the 16 studies indicated that UK-based researchers are beginning to adopt more rigorous research methods. However, there was a tendency for researchers to evaluate interventions over a relatively short time-frame. The implications of these findings for future research are discussed.

Novel and effective treatment modality for medically unexplained symptoms

Medically unexplained symptoms (MUS) confound physicians, and the incidence and prevalence of these conditions is poorly documented.  This is not least due to the complex nature of MUS and mimicry of morbidity with conditions that have common clinical assessment and treatment modalities, e.g. migraine headaches which stress headaches commonly are misdiagnosed as.  Effective treatment modalities for MUS have been more or less non-existent.  In the following we present a modality for the assessment, diagnosis and treatment of MUS that in our experience leads to cure, at least in better than half of these cases measured in terms of allowing the individual back to work.  These results are at least twice as high as those described hitherto (see below), and yet, our treatment modality is beset with many obstacles, not the least of which is the intrasigence of a system that will not and/or can not understand why this modality is so much better than what they are able to offer.  The most importance obstacle is financing, as this modality requires long term and committed financing to work.  The economic implications of not dealing with these issues are described.

Is internet-based CBT for panic disorder and agoraphobia as effective as face-to-face CBT

This study compared Panic Online (PO), an internet-based CBT intervention, to best-practice face-to-face CBT for people with panic disorder with or without agoraphobia. Eighty-six people with a primary diagnosis of panic disorder were recruited from Victoria, Australia. Participants were randomly assigned to either PO (n = 46) or best practice face-to-face CBT (n = 40). Effects of the internet-based CBT program were found to be comparable to those of face-to-face CBT. Both interventions produced significant reductions in panic disorder and agoraphobia clinician severity ratings, self reported panic disorder severity and panic attack frequency, measures of depression, anxiety, stress and panic related cognitions, and displayed improvements in quality of life. Participants rated both treatment conditions as equally credible and satisfying. Participants in the face-to-face CBT treatment group cited higher enjoyment with communicating with their therapist. Consistent with this, therapists’ ratings for compliance to treatment and understanding of the CBT material was higher in the face-to-face CBT treatment group. PO required significantly less therapist time than the face-to-face CBT condition.