Subjective reaction to vertical mechanical shocks of various waveforms

1991 ◽  
Vol 147 (3) ◽  
pp. 395-408 ◽  
Author(s):  
H.V.C. Howarth ◽  
M.J. Griffin
2021 ◽  
Vol 13 (2) ◽  
pp. 494
Author(s):  
Antonio Algar ◽  
Javier Freire ◽  
Robert Castilla ◽  
Esteban Codina

The internal cushioning systems of hydraulic linear actuators avoid mechanical shocks at the end of their stroke. The design where the piston with perimeter grooves regulates the flow by standing in front of the outlet port has been investigated. First, a bond graph dynamic model has been developed, including the flow throughout the internal cushion design, characterized in detail by computational fluid-dynamic simulation. Following this, the radial movement of the piston and the fluid-dynamic coefficients, experimentally validated, are integrated into the dynamic model. The registered radial movement is in coherence with the significant drag force estimated in the CFD simulation, generated by the flow through the grooves, where the laminar flow regime predominates. Ultimately, the model aims to predict the behavior of the cushioning during the movement of the arm of an excavator. The analytical model developed predicts the performance of the cushioning system, in coherence with empirical results. There is an optimal behavior, highly influenced by the mechanical stress conditions of the system, subject to a compromise between an increasing section of the grooves and an optimization of the radial gap.


Author(s):  
M. S. Chafi ◽  
V. Dirisala ◽  
G. Karami ◽  
M. Ziejewski

In the central nervous system, the subarachnoid space is the interval between the arachnoid membrane and the pia mater. It is filled with a clear, watery liquid called cerebrospinal fluid (CSF). The CSF buffers the brain against mechanical shocks and creates buoyancy to protect it from the forces of gravity. The relative motion of the brain due to a simultaneous loading is caused because the skull and brain have different densities and the CSF surrounds the brain. The impact experiments are usually carried out on cadavers with no CSF included because of the autolysis. Even in the cadaveric head impact experiments by Hardy et al. [1], where the specimens are repressurized using artificial CSF, this is not known how far this can replicate the real functionality of CSF. With such motivation, a special interest lies on how to model this feature in a finite element (FE) modeling of the human head because it is questionable if one uses in vivo CSF properties (i.e. bulk modulus of 2.19 GPa) to validate a FE human head against cadaveric experimental data.


1989 ◽  
Vol 7 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Peter L. Derks

Shakespeare's mixing of comedy and tragedy was not popular with his contemporaries. Modern research on emotion, however, indicates that the combination of conflicting arousal sources will increase subjective reaction and, perhaps, audience enthusiasm. To examine this possibility, citation estimates of each play's popularity were compared with two examples each of sexual or intellectual pun frequency counts. Sexual punning frequency did not predict popularity, while increased frequency of intellectual punning accompanied increased tragedy popularity and decreased comedy popularity.


Author(s):  
Марина Владиславовна Минстер

В статье рассматриваются причины и факторы, способствующие возникновению пенитенциарного стресса у осужденных к лишению свободы женщин. Стресс как субъективная реакция психики на изоляцию от общества больше связан с воздействием пенитенциарной среды и способствует развитию деструктивных проявлений у женщин, что негативно влияет на исправительное воздействие и часто проявляется на стадии адаптации и перед освобождением. В гендерном аспекте результаты исследования показали, что осужденные к лишению свободы мужчины проявляют устойчивость к стрессорным воздействиям при высоком уровне стресса, депрессивные состояния среди них в несколько раз меньше, чем у женщин. Пенитенциарный стресс у женщин является более контрастным, так как уровень психоэмоциональных переживаний выше и требуется значительно больше времени для восстановления, чем мужчинам. Исследуется практика применения индивидуальных и групповых психокоррекционных методик, осуществляемых в процессе исполнения наказания, которые создают условия для самоисправления женщины. Оптимизация исправительного воздействия возможна при условии включения осужденных женщин в воспитательно-ресоциализационные и социально-реабилитационные программы с учетом психофизиологических особенностей и анализа психодинамики их активности, с использованием дополнительного положительного влияния близких родственников и общественности на разных этапах отбывания наказания. The article discusses the causes and factors contributing to stress in prison of persons sentenced to deprivation of liberty of women. Stress as a subjective reaction of the psyche to isolation from society is more related to the impact of the prison environment and contributes to the development of destructive manifestations in women, which negatively affects the corrective effect and often manifests itself at the stage of adaptation and before release. In the gender aspect, the results of the study showed that men sentenced to imprisonment show resistance to stress at a high level of stress, depression among them several times less, unlike women. Penitentiary stress in women is more contrast, because the level of psycho-emotional experiences is higher and it takes much more time to recover than men. The author of the article studies the practice of applying individual and group psychocorrection techniques carried out in the process of execution of punishment, which create conditions for self-correction of women. Optimization of treatment possible, subject to the inclusion of women offenders in a correctional reintegration and social rehabilitation programme taking into account psycho-physiological characteristics and analysis of the psychodynamics of activity, using the influence of relatives and the public at various stages of punishment.


2016 ◽  
Vol 2016 (1) ◽  
pp. 000106-000110
Author(s):  
Jia-Shen Lan ◽  
Stuwart Fan ◽  
Louie Huang ◽  
Mei-Ling Wu

Abstract In this paper, the solder joint failure and the solder joint fatigue life in the Thin-profile Fine-pitch Ball Grid Array (TFBGA) Package was investigated by performing the drop test, and implementing a simulation model. Owing to the need to meet the increasing demands for functionality, microelectronic package reliability can be compromised and has become the key issue when executing drop tests. During impact in drop test, the deformation of PCB due to bending and mechanical shocks can cause solder joint crack. While this is a well-known issue, observing the solder joint responses during the test execution can be a challenge. Therefore, in this work, a simulation model approach has been developed to investigate the stress and strain of the solder joint during the drop test. In this research, the JEDEC Condition B drop test was simulated, characterized by 1500G peak acceleration and 0.5 ms duration. The drop test simulation model was successful in predicting the solder joint fatigue life with different solder joint materials, such as SAC105 and SAC1205N, while also facilitating result comparison to identify the most optimal structure.


1997 ◽  
Vol 3 (S2) ◽  
pp. 1249-1250
Author(s):  
Paul D. Peterson ◽  
Deanne J. Idar ◽  
John S. Gardner

A recent study concluded that the most potentially dangerous scenarios for accidental detonation of a nuclear weapon were those involving weak thermal or mechanical shocks. For this reason, more data are needed to understand the material behavior of nuclear constituents under low strain rate scenarios.One of the components of many of these types of weapons is known as Plastic Bonded eXplosives (PBX). PBX is a paniculate composite material made of a hard phase explosive carried in a soft phase polymer binder. Recent work has showed that the stiffness of PBX increased under low rate compressive loading. This behavior was attributed to the shape of the test samples and cross-linking within the elastomer binder. Another theory proposed that the changing compressive properties could be attributed to the hard phase particles migrating together during material flow.Funk et al. demonstrated an inert material mock of PBX 9501, with the hard phase explosive replaced by granular sugar, also showed the same phenomena of compressive hardening.


1996 ◽  
Vol 193 (1) ◽  
pp. 65-74 ◽  
Author(s):  
E.G Vadillo ◽  
J. Herreros ◽  
J.G. Walker

Spine ◽  
2018 ◽  
Vol 43 (8) ◽  
pp. E482-E487 ◽  
Author(s):  
Tobias Carl Stenlund ◽  
Fredrik Öhberg ◽  
Ronnie Lundström ◽  
Ola Lindroos ◽  
Charlotte K. Häger ◽  
...  

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