Characterization of Fluid-Filled Interconnected Dual-Cells for Reduction of Force and Linear Acceleration due to Blunt Impact

Author(s):  
Veysel Erel ◽  
Alexandra R. Lindsay ◽  
Inderjeet Singh ◽  
Muthu B. J. Wijesundara

Abstract Although modern body and head protective gears are well studied by experts, innovators, and manufacturers, incidence of sports-related injuries is still very high in the United States and all around the world. To reduce the negative effects from blunt impact, an impact reduction structure which contains a channel, shell, and dual-cells was designed and developed with the intention of improving existing helmet liners. This study utilized a previously proven interconnected-cells concept, where a primary cell compresses, then air inside the cell transfers to a secondary cell which expands accordingly, causing impact reduction. While the concept remained the same, a new dual-cells architecture was explored, with numerical and experimental studies for helmet liner impact reduction, and compared to a commercial Xenith helmet liner element. The simulation study began with exploring the effect of adding corrugation to the walls of both cells on impact behavior, then persisted with optimizing impact reduction structure design, and finalized with a comparison study. An experimental study was performed with the optimized structure, provided by simulation, and compared against commercial Xenith helmet liner element in terms of reaction force, linear acceleration, and impact duration. Experimental and simulation results showed that our impact reduction structure provides lower reaction force and linear acceleration.

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1749
Author(s):  
Sage Mijares ◽  
Michelle Calvo-Lorenzo ◽  
Nick Betts ◽  
Lacey Alexander ◽  
Lily N. Edwards-Callaway

The COVID-19 pandemic had significant consequences on cattle slaughter capacity in the United States. Although industry stakeholders implemented strategies to minimize cattle welfare impacts of increased weights, days on feed (DOF), and increasing temperatures, there were concerns that mobility challenges would be observed at slaughter facilities. The objectives of this study were to characterize mobility in fed cattle during this recovery period and to identify factors impacting mobility. A total of 158 groups of cattle (15,388 animals) from one slaughter facility were included in the study. A 4-point mobility scoring system was used to assess cattle mobility. Cattle at the facility with normal mobility scores were reduced from the historical average of 96.19% to 74.55%. No increase in highly elevated mobility scores was observed. Mobility was impacted by weight, temperature humidity index (THI), distance hauled, sex, and DOF, with results differing by mobility category. Weather was a key contributor to mobility challenges; the relative risk of observing an elevated mobility score was 45.76% greater when the THI changed from No Stress to Mild Stress. Despite the challenges that the industry faced during this period, efforts to minimize negative effects on cattle welfare by enhanced focus on low-stress handling were effective.


2021 ◽  
Author(s):  
Veysel Erel ◽  
Alexandra Lindsay ◽  
Muthu B. J. Wijesundara ◽  
Inderjeet Singh

2018 ◽  
Vol 62 (2) ◽  
pp. 97-107 ◽  
Author(s):  
Nina Keith

Abstract. The positive effects of goal setting on motivation and performance are among the most established findings of industrial–organizational psychology. Accordingly, goal setting is a common management technique. Lately, however, potential negative effects of goal-setting, for example, on unethical behavior, are increasingly being discussed. This research replicates and extends a laboratory experiment conducted in the United States. In one of three goal conditions (do-your-best goals, consistently high goals, increasingly high goals), 101 participants worked on a search task in five rounds. Half of them (transparency yes/no) were informed at the outset about goal development. We did not find the expected effects on unethical behavior but medium-to-large effects on subjective variables: Perceived fairness of goals and goal commitment were least favorable in the increasing-goal condition, particularly in later goal rounds. Results indicate that when designing goal-setting interventions, organizations may consider potential undesirable long-term effects.


2020 ◽  
Vol 25 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Amaia Del Campo ◽  
Marisalva Fávero

Abstract. During the last decades, several studies have been conducted on the effectiveness of sexual abuse prevention programs implemented in different countries. In this article, we present a review of 70 studies (1981–2017) evaluating prevention programs, conducted mostly in the United States and Canada, although with a considerable presence also in other countries, such as New Zealand and the United Kingdom. The results of these studies, in general, are very promising and encourage us to continue this type of intervention, almost unanimously confirming its effectiveness. Prevention programs encourage children and adolescents to report the abuse experienced and they may help to reduce the trauma of sexual abuse if there are victims among the participants. We also found that some evaluations have not considered the possible negative effects of this type of programs in the event that they are applied inappropriately. Finally, we present some methodological considerations as critical analysis to this type of evaluations.


2020 ◽  
Author(s):  
Wallace Derricotte ◽  
Huiet Joseph

The mechanism of isomerization of hydroxyacetone to 2-hydroxypropanal is studied within the framework of reaction force analysis at the M06-2X/6-311++G(d,p) level of theory. Three unique pathways are considered: (i) a step-wise mechanism that proceeds through formation of the Z-isomer of their shared enediol intermediate, (ii) a step-wise mechanism that forms the E-isomer of the enediol, and (iii) a concerted pathway that bypasses the enediol intermediate. Energy calculations show that the concerted pathway has the lowest activation energy barrier at 45.7 kcal mol<sup>-1</sup>. The reaction force, chemical potential, and reaction electronic flux are calculated for each reaction to characterize electronic changes throughout the mechanism. The reaction force constant is calculated in order to investigate the synchronous/asynchronous nature of the concerted intramolecular proton transfers involved. Additional characterization of synchronicity is provided by calculating the bond fragility spectrum for each mechanism.


Author(s):  
Abigail A. Fagan ◽  
Kristen M. Benedini

This chapter reviews the degree to which empirical evidence demonstrates that families influence youth delinquency. Because they are most likely to be emphasized in life-course theories, this chapter focuses on parenting practices such as parental warmth and involvement, supervision and discipline of children, and child maltreatment. It also summarizes literature examining the role of children's exposure to parental violence, family criminality, and young (teenage) parents in affecting delinquency. Because life-course theories are ideally tested using longitudinal data, which allow examination of, in this case, the impact of parenting practices on children's subsequent behaviors, this chapter focuses on evidence generated from prospective studies conducted in the United States and other countries. It also discusses findings from experimental studies designed to reduce youth substance use and delinquency by improving the family environment.


2021 ◽  
Vol 31 (1-2) ◽  
pp. 7-28
Author(s):  
April L. Peters ◽  
Angel Miles Nash

The rallying, clarion call to #SayHerName has prompted the United States to intentionally include the lives, voices, struggles, and contributions of Black women and countless others of her ilk who have suffered and strived in the midst of anti-Black racism. To advance a leadership framework that is rooted in the historicity of brilliance embodied in Black women’s educational leadership, and their proclivity for resisting oppression, we expand on intersectional leadership. We develop this expansion along three dimensions of research centering Black women’s leadership: the historical foundation of Black women’s leadership in schools and communities, the epistemological basis of Black women’s racialized and gendered experiences, and the ontological characterization of Black women’s expertise in resisting anti-Black racism in educational settings. We conclude with a four tenet articulation detailing how intersectional leadership: (a) is explicitly anti-racist; (b) is explicitly anti-sexist; (c) explicitly acknowledges the multiplicative influences of marginalization centering race and gender, and across planes of identity; and (d) explicitly leverages authority to serve and protect historically underserved communities.


2021 ◽  
Vol 44 (3) ◽  
Author(s):  
T KALAIARASI ◽  
M SENTHILKUMAR ◽  
S SHANMUGAN ◽  
T JARIN ◽  
V CHITHAMBARAM ◽  
...  

2021 ◽  
pp. 014544552098613
Author(s):  
Bailee B. Schuhmann ◽  
Sarah N. Henderson ◽  
Ryan A. Black ◽  
Vincent B. Van Hasselt ◽  
Kristin Klimley Margres ◽  
...  

Research has documented a number of acute and chronic stressors unique to the fire service. Due to the rise in mental health concerns in firefighters, there has been increased awareness of the negative effects of unmanaged stress. The present study employed a behavioral-analytic model to construct a brief screening measure of stress for this population: the Firefighter Assessment of Stress Test (FAST). Psychometric properties of the FAST were evaluated using data from active-duty firefighters throughout the United States. Results indicated the FAST has good internal reliability ( α = 0.89), as well as good convergent and discriminant validity. Also, the factor structure of the FAST revealed three significant subscales reflective of stress associated with responding to calls, administrative difficulties, and being overworked. Scoring and interpretation guidelines were established to suggest when further assessment is warranted. The FAST offers a brief and valid method of self-assessment of current stress levels in firefighters. Information obtained from the FAST (i.e., overall stress level and domains) has the potential to facilitate more immediate identification and recognition of stress in firefighters than what has been possible to date. Moreover, heightened awareness of stress and its effects will hopefully culminate in expanded efforts directed toward stress reduction and intervention for firefighters and their families.


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