Experimental Mechanics

1985 ◽  
Vol 38 (10) ◽  
pp. 1279-1281
Author(s):  
R. J. Clifton ◽  
F. P. Chiang

Mechanical failure of machine parts, structures, and microelectronic components has a strong negative impact on the safety, security, and productivity of our people. Prevention of these failures is a principal focus of solid mechanics, which uses analysis, experiment, and computation to provide the understanding necessary for failure reduction through improved design, fabrication, and inspection. Experimental mechanics plays a critical role in this effort since it provides the data base for the calculations and the means for testing the validity of proposed theoretical models of failure. Current trends in experimental mechanics show increased use of optical methods for monitoring the displacements, velocities, and strains of surfaces. This trend has gained impetus from the attractiveness of noncontact methods for hostile environments and dynamically loaded bodies. Advances in laser technology have enhanced the instrumentation associated with these methods. Another trend is the investigation of material behavior under more complex loading conditions, made possible by the availability of servo-controlled testing machines with computer interfaces. Still another trend is the increased attention given to defects, such as inclusions, cracks, and holes, because of their importance in failure mechanisms. Opportunities for future contributions from experimental mechanics appear to be great and to occur across a broad range of technological problems. A central theme of future research appears to be increased emphasis on measurements at the micron and submicron scale in order to advance the understanding of material response and failure at the micromechanical level. Increased attention will also be given to internal measurements of defects, deformations and residual stresses because of their importance in developing a fundamental understanding of failure. Automated data reduction and control of experiments will greatly increase the information obtained from experiments and its usefulness for the development of mathematical models. Other important research directions include improved methods for measurements of in situ stresses in rocks, improved measurements of displacements and physiological parameters in biological systems, capability for long-term monitoring of the integrity of structures, and improved sensors for feedback control of mechanical systems.

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4332
Author(s):  
Pedro Veiga Rodrigues ◽  
Bruno Ramoa ◽  
Ana Vera Machado ◽  
Philip Cardiff ◽  
João Miguel Nóbrega

Toe caps are one of the most important components in safety footwear, but have a significant contribution to the weight of the shoe. Efforts have been made to replace steel toe caps by polymeric ones, since they are lighter, insulated and insensitive to magnetic fields. Nevertheless, polymeric solutions require larger volumes, which has a negative impact on the shoe’s aesthetics. Therefore, safety footwear manufacturers are pursuing the development of an easy, low-cost and reliable solution to optimize this component. In this work, a solid mechanics toolbox built in the open-source computational library, OpenFOAM®, was used to simulate two laboratory standard tests (15 kN compression and 200 J impact tests). To model the polymeric material behavior, a neo-Hookean hyper-elasto-plastic material law with J2 plastic criteria was employed. A commercially available plastic toe cap was characterized, and the collected data was used for assessment purposes. Close agreements, between experimental and simulated values, were achieved for both tests, with an approximate error of 5.4% and 6.8% for the displacement value in compression and impact test simulations, respectively. The results clearly demonstrate that the employed open-source finite volume computational models offer reliable results and can support the design of toe caps for the R&D footwear industry.


Crisis ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Amanda Venta ◽  
Carla Sharp

Background: Identifying risk factors for suicide-related thoughts and behaviors (SRTB) is essential among adolescents in whom SRTB remain a leading cause of death. Although many risk factors have already been identified, influential theories now suggest that the domain of interpersonal relationships may play a critical role in the emergence of SRTB. Because attachment has long been seen as the foundation of interpersonal functioning, we suggest that attachment insecurity warrants attention as a risk factor for SRTB. Aims: This study sought to explore relations between attachment organization and suicidal ideation, suicide attempts, and self-harm in an inpatient adolescent sample, controlling for demographic and psychopathological covariates. Method: We recruited 194 adolescents from an inpatient unit and assigned them to one of four attachment groups (secure, preoccupied, dismissing, or disorganized attachment). Interview and self-report measures were used to create four variables reflecting the presence or absence of suicidal ideation in the last year, single lifetime suicide attempt, multiple lifetime suicide attempts, and lifetime self-harm. Results: Chi-square and regression analyses did not reveal significant relations between attachment organization and SRTB, although findings did confirm previously established relations between psychopathology and SRTB, such that internalizing disorder was associated with increased self-harm, suicide ideation, and suicide attempt and externalizing disorder was associated with increased self-harm. Conclusion: The severity of this sample and methodological differences from previous studies may explain the nonsignificant findings. Nonsignificant findings may indicate that the relation between attachment organization and SRTB is moderated by other factors that should be explored in future research.


2021 ◽  
Vol 42 (1) ◽  
pp. e8-e16 ◽  
Author(s):  
Angelica Tiotiu

Background: Severe asthma is a heterogeneous disease that consists of various phenotypes driven by different pathways. Associated with significant morbidity, an important negative impact on the quality of life of patients, and increased health care costs, severe asthma represents a challenge for the clinician. With the introduction of various antibodies that target type 2 inflammation (T2) pathways, severe asthma therapy is gradually moving to a personalized medicine approach. Objective: The purpose of this review was to emphasize the important role of personalized medicine in adult severe asthma management. Methods: An extensive research was conducted in medical literature data bases by applying terms such as “severe asthma” associated with “structured approach,” “comorbidities,” “biomarkers,” “phenotypes/endotypes,” and “biologic therapies.” Results: The management of severe asthma starts with a structured approach to confirm the diagnosis, assess the adherence to medications and identify confounding factors and comorbidities. The definition of phenotypes or endotypes (phenotypes defined by mechanisms and identified through biomarkers) is an important step toward the use of personalized medicine in asthma. Severe allergic and nonallergic eosinophilic asthma are two defined T2 phenotypes for which there are efficacious targeted biologic therapies currently available. Non-T2 phenotype remains to be characterized, and less efficient target therapy exists. Conclusion: Despite important progress in applying personalized medicine to severe asthma, especially in T2 inflammatory phenotypes, future research is needed to find valid biomarkers predictive for the response to available biologic therapies to develop more effective therapies in non-T2 phenotype.


Author(s):  
Landiswa Seteni ◽  
Pierre Joubert ◽  
Manilall Dhurup

Over the past decade, South African organisations have had to cope with an ever-increasing rate of local and global changes. There have been considerable and ongoing socio-political changes, resulting from new government regulations. Most organisations have experienced some type of downturn, whether due to external business factors or poor internal performance. A typical response to organisational decline is retrenchment. Our study sought to explore employees’ perceptions of the effects of retrenchment on job stress and organisational commitment in a mining company. The study was located within a quantitative research paradigm. Four research hypotheses were posited and data was collected in one region from a sample of 400 surface mining employees, including management, administrators, engineers and artisans. The results showed that the effects of retrenchment did not have a negative impact on job stress (time stress and anxiety). This may be due to the fact that the mining company in question had a planning and consultation process in place for the employees prior to the retrenchment process. The results also showed that job stress (time stress and anxiety) was negatively associated with organisational commitment. To conclude this article we discuss the implications of our findings, outline the limitations of our study and make recommendations for future research.


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Charles James ◽  
Catherine Walshe ◽  
Katherine Froggatt

Abstract Background The knowledge about the experience of informal caregivers who provide care to people with moderate to advanced dementia in a domestic home setting is limited. A consequence of long hours of caregiving in addition to dealing with normal challenges of daily living is their experience of a poor quality of life. Some of their experiences may be described in terms of a feeling of powerlessness to make changes during care provision. This feeling may also suggest an experience of moral distress. The aim of this systematic review is to synthesise qualitative evidence relating to these experiences. Methods This review adopts a narrative synthesis approach. A search will be conducted for studies written in the English language in the bibliographic databases MEDLINE Complete, CINAHL, EMBASE, PsycINFO, Web of Science and Academic Search Complete covering periods from 1984 to present. Included studies will be qualitative or mixed-methods designs. The search terms will be related to dementia and caregivers, and the process will be focused on dementia at the moderate to the advanced stages within the domestic home setting. Reference lists of included papers will also be searched for additional relevant citations. Search terms and strategies will be checked by two independent reviewers. The identification of abstracts and full texts of studies will be done by the author, while the quality and the risk of bias will also be checked by the two independent reviewers. Discussion Psychological distress is cited as an experience reported within informal caregiving. For the caregiver, it is associated with a negative impact on general health. To date, no synthesis exists on the specific experience of informal caregiving for people with moderate to advanced dementia within the domestic home setting. This review considers that variation of accounts contributes to how the informal caregivers’ general experience is explored in future research. This may enable gaps in current knowledge to be highlighted within the wider context of caregiving in the domestic home setting. Systematic review registration This review is registered with PROSPERO (CRD42020183649).


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1271.1-1272
Author(s):  
S. Derham ◽  
J. Lewis ◽  
E. Dures ◽  
F. Cramp

Background:Adults with fibromyalgia frequently report symptoms of cognitive dysfunction, often referred to as fibrofog. However primary research exploring cognitive dysfunction in the lives of adults with fibromyalgia is very limited (Kravitz and Katz, 2015).Objectives:The aim of this review was to (i) synthesise the qualitative literature on the lived experiences of cognitive dysfunction in adults with fibromyalgia, (ii) develop common themes through thematic analysis and (iii) identify knowledge gaps to inform future research and clinical practice in this area.Methods:Seven electronic databases (MEDLINE, Embase, CINAHL, PsycINFO, Amed, Scopus and OpenGrey), reference lists of key articles and two high impact qualitative journals were searched from 1990 to November 2018. Articles were eligible for inclusion if they reported primary qualitative data exploring the experiences of cognitive dysfunction in adults with fibromyalgia. Included studies were appraised using the Critical Appraisal Skills Programme (CASP) qualitative checklist and extracted data analysed using narrative synthesis. SD conducted critical appraisal and data extraction on all included studies. FC, JL and ED reviewed five papers each. All papers were reviewed by two co-authors. Of the 1413 records identified, 15 studies were selected for inclusion.Results:These studies included 208 women and 22 men with fibromyalgia, aged 18 to 72 years and representing seven different countries. Duration of diagnosis was four months to 34 years. Fourteen studies used interviews and one used focus groups. None of the included studies focussed exclusively on cognitive function in adults with fibromyalgia. Three studies identified themes specific to cognitive dysfunction and fibromyalgia symptoms. The remaining 12 studies presented relevant data intertwined with the overall lived experiences of fibromyalgia.Cognitive dysfunction, as a part of fibromyalgia, was often unpredictable. Problems with memory and concentration that were most commonly reported were emotionally distressing and affected functional and vocational activities. Participants found communication effortful, with a negative impact on work, leisure and social activities. Stress, fear and worry around perceived cognitive changes were commonly expressed. Lost employment or changed work roles and relationships, due to cognitive difficulties, had negative impacts for many participants. The terms cognitive dysfunction and fibrofog were used interchangeably within the studies, but lacked common definition. This introduced uncertainty around whether participants and authors were describing the same phenomenon.Conclusion:Adults with fibromyalgia experience unpredictable and emotionally impactful difficulties related to cognitive dysfunction. Functional impact was broad-reaching, particularly around work ability and lost employment opportunities. It is unclear how cognitive symptoms in fibromyalgia related to co-morbid symptoms such as pain, fatigue and poor sleep. Further research focusing on the full impact of cognitive function on the lives of adults with fibromyalgia is recommended to inform clinical practice. Research to establish clarity of definition of the terms cognitive dysfunction and fibrofog within fibromyalgia is highly recommended.References:[1]Kravitz H, Katz R. Fibrofog and fibromyalgia: a narrative review and implications for clinical practice. Rheumatology International. 2015;35(7):1115-25.Acknowledgments:This work is supported by the National Institute for Heath Research [ICA-PCAF-2018-01-078 to SD]Disclosure of Interests:Sandra Derham: None declared, Jenny Lewis: None declared, Emma Dures Grant/research support from: Independent Learning Grant from Pfizer, combined funding for a research fellow from Celgene, Abbvie and Novartis, Paid instructor for: A fee from Novartis to deliver training to nurses., Fiona Cramp: None declared


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Brianne A. Bruijns ◽  
Andrew M. Johnson ◽  
Jennifer D. Irwin ◽  
Shauna M. Burke ◽  
Molly Driediger ◽  
...  

Abstract Background Early childhood educators (ECEs) play a critical role in promoting physical activity (PA) among preschoolers in childcare; thus, PA-related training for ECEs is essential. The Supporting PA in the Childcare Environment (SPACE) intervention incorporated: 1. shorter, more frequent outdoor play sessions; 2. provision of portable play equipment; and, PA training for ECEs. An extension of the SPACE intervention (the SPACE-Extension) incorporated only the shorter, more frequent outdoor play periods component of the original SPACE intervention. The purpose of this study was to explore the individual impact of these interventions on ECEs’ PA-related self-efficacy and knowledge. Methods ECEs from the SPACE (n = 83) and SPACE-Extension (n = 31) were administered surveys at all intervention time-points to assess: self-efficacy to engage preschoolers in PA (n = 6 items; scale 0 to 100); self-efficacy to implement the intervention (n = 6 items); and, knowledge of preschooler-specific PA and screen-viewing guidelines (n = 2 items). A linear mixed effects model was used to analyze the impact of each intervention on ECEs’ self-efficacy and knowledge and controlled for multiple comparison bias. Results The SPACE intervention significantly impacted ECEs’ self-efficacy to engage preschoolers in PA for 180 min/day (main effect), and when outdoor playtime was not an option (interaction effect). Further, the interaction model for ECEs’ knowledge of the total PA guideline for preschoolers approached significance when compared to the main effects model. Participants within the SPACE-Extension did not demonstrate any significant changes in self-efficacy or knowledge variables. Conclusions Findings from this study highlight the benefit of ECE training in PA with regard to fostering their PA-related self-efficacy and knowledge. Future research should explore the impact of PA training for ECEs uniquely in order to determine if this intervention component, alone, can produce meaningful changes in children’s PA behaviours at childcare.


Thermo ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 63-76
Author(s):  
Mengxuan Yan ◽  
Dongxiao Wang ◽  
Chun Sing Lai ◽  
Loi Lei Lai

Microgrids have become increasingly popular in recent years due to technological improvements, growing recognition of their benefits, and diminishing costs. By clustering distributed energy resources, microgrids can effectively integrate renewable energy resources in distribution networks and satisfy end-user demands, thus playing a critical role in transforming the existing power grid to a future smart grid. There are many existing research and review works on microgrids. However, the thermal energy modelling in optimal microgrid management is seldom discussed in the current literature. To address this research gap, this paper presents a detailed review on the thermal energy modelling application on the optimal energy management for microgrids. This review firstly presents microgrid characteristics. Afterwards, the existing thermal energy modeling utilized in microgrids will be discussed, including the application of a combined cooling, heating and power (CCHP) and thermal comfort model to form virtual energy storage systems. Current trial programs of thermal energy modelling for microgrid energy management are analyzed and some challenges and future research directions are discussed at the end. This paper serves as a comprehensive review to the most up-to-date thermal energy modelling applications on microgrid energy management.


2021 ◽  
Vol 30 (10) ◽  
pp. S30-S37
Author(s):  
Sophie Biddle

Introduction: Active surveillance is a conservative management approach to treating prostate cancer involving regular testing and close monitoring by the health professional. The aim of this literature review is to establish whether men experience a psychological impact of active surveillance and what the prevalent effects might be. Method: The search was carried out in three databases: CINAHL, Medline and PsycINFO. Articles published in English, from October 2015 to March 2018, which focused on the psychological impact of active surveillance, were included. Findings: A total of eight quantitative studies were included in this report. The review identified key psychological impacts of active surveillance, including anxiety, sub-clinical depression, illness uncertainty and hopelessness. Active surveillance was seen by some patients as a positive treatment approach that limited the side effects associated with active treatment. Conclusion: The evidence found a negative impact of active surveillance might be felt by men at any stage during treatment and at differing levels of severity. The article highlights key demographic areas, including ethnicity and age, for future research and recommends more qualitative studies are conducted.


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