Effect of the foam embellishments on the pedestrian safety of the vehicle front protection systems

Pedestrian safety related compliance requirements are very important in case of design and development of the vehicle front protection systems. Computer aided engineering impact simulations were carried out to evaluate Head Injury Criterion (HIC) of a typical bullbar impacting it with an adult headform and correlated with experimental results. Impact simulations were carried out on the same bullbar covered with semi‐rigid polyurethane foam to study the effect of foam embellishments on the pedestrian safety. Results obtained from the impact simulations were presented in this paper

Magnetocaloric effect and improved relative cooling power in (La0.7Sr0.3MnO3/SrRuO3) superlattices

Magnetic properties of a series of (La0.7Sr0.3MnO3/SrRuO3) superlattices, where the SrRuO3 layer thickness is varying, are examined. A room-temperature magnetocaloric effect is obtained owing to the finite size effect which reduces the TC of La0.7Sr0.3MnO3 layers. While the working temperature ranges are enlarged,, -DeltaSmax values remains similar to the values in polycrystalline La0.7Sr0.3MnO3. Consequently, the relative cooling powers are significantly improved, the microscopic mechanism of which is related to the effect of the interfaces at La0.7Sr0.3MnO3/SrRuO3 and higher nanostructural disorder. This study indicates that artificial oxide superlattices/multilayers might provide an alternative pathway in searching for efficient room-temperature magnetic refrigerators for (nano)microscale systems.Comment: 14^pages, 3 figures, Submitted to J. Phys. Cond. Ma

Coassembly Generates Peptide Hydrogel with Wound Dressing Material Properties

Multicomponent self-assembly of peptides is a powerful strategy to fabricate novel functional materials with synergetic properties that can be used for several nanobiotechnological applications. In the present study, we used a coassembly strategy to generate an injectable ultrashort bioactive peptide hydrogel formed by mixing a dipeptide hydrogelator with a macrophage attracting short chemotactic peptide ligand. Coassembly does not impede hydrogelation as shown by cryo-transmission electron microscopy (cryo-TEM), scanning electron microscopy, and rheology. Biocompatibility was shown by cytotoxicity assays and confocal microscopy. The hydrogels release the entrapped skin antibiotic ciprofloxacin, among others, in a slow and continuous manner. Such bioinspired advanced functional materials can find applications as wound dressing materials to treat chronic wound conditions like diabetic foot ulcer

Evaluation of the blunt thoracic trauma due to baseball impacts – review of the Blunt Criterion

Evaluation of the thoracic injury due to blunt impacts during the contact and collision sports activity is crucial for the development and validation of the chest protectors and safety solid sports for the athletes. In the case of young athletes, proper chest protectors can avoid not only severe chest trauma but also protect them from the sudden death due to commotio-cordis. In order to evaluate the thoracic injury in terms of known engineering parameters (Viscous Criterion), non-linear finite element simulations were carried out by impacting FE model of the thorax surrogate (MTHOTA- Mechanical THOrax for Trauma Assessment) with a synthetic baseball and a synthetic baseball of the same size and weight at the impact speed of 10 – 45 m/s (with an increment of 5 m/s). Synthetic baseball and soft-core baseball produced VCmax = 1 m/s at the impact speed of 27.9 m/s and 30.7 m/s respectively. For both sports ball impact cases, Blunt Criterion (which is commonly used as non-lethal munitions design criterion that takes only kinetic energy of the projectile and weight & geometry of the thorax into consideration) was evaluated for all impact cases of two types of baseballs. Results have revealed the projectile specificity of the Blunt Criterion

Review of anthropomorphic test dummies for the evaluation of thoracic trauma due to blunt ballistic impacts

Biomechanical responses of the thoraces of finite element models of 4 Anthropomorphic Test Dummies (namely, LSTC Hybrid III deformable, LSTC Hybrid III rigid, LSTC/NCAC Hybrid III and ES-2re) were reviewed by impacting them with the 140 gram wooden projectile with impact speeds of 20 and 40 m/s, and 30 g wooden projectile with 60 m/s. In order to elucidate the usefulness of the ATDs for evaluating blunt thoracic trauma caused by blunt ballistic impacts (projectile mass 20 – 200 gram, velocity 20 – 250 m/s), responses obtained were compared with the human response corridors developed by Wayne State University’s researchers. It was evident that none of the thoraces exhibited bio-fidelity for the impact cases considered for the analysis. Thoraces of former three dummies found to be very stiff and the latter yielded realistic responses but Viscous Criterion (VCmax) values based on the deflection response were way higher when compared to those obtained from the cadaveric experiments for the similar impact conditions. Values of viscous criterion (VCmax), probability for AIS3+ and AIS4+ injuries based on the maximum rib deflections (only for the ES-2re dummy for particular impact locations), were found to be, for some cases, to a certain extent, in agreement with those obtained from the cadaveric experiments. The present study highlights the unsuitability of the numerous thorax models (both physical and finite element), while necessitating the development of the thorax surrogate with an acceptable biofidelity. Such biomechanical surrogate of the thorax, for the evaluation of trauma, is essential for the validation of non-lethal ammunition, development of bullet proof vests and chest protectors for the athletes of collision & contact sports

Effect of energy absorbing mechanisms on the blunt thoracic trauma caused by ballistic impacts

military and law enforcement officials have been using kinetic energy non-lethal weapons ranging from rubber bullets to projectiles with foam in situations which do not warrant the usage of lethal force. On many occasions, non-lethal projectiles have caused serious injuries. Therefore, a scholastic study was carried out to see the effect on the injury caused by the projectiles embedded with various energy absorbing mechanisms. Projectile – target interaction (kinetic energy transfer or energy gained by the target and Total energy of the projectile) plays a vital role in understanding the effect of the projectile on the target. Therefore, to evaluate the effect of the energy absorbing mechanisms on the blunt thoracic trauma, target considered should emulate the human thorax as far as the projectile-thorax interaction is concerned. A fully validated FE model of the thoracic surrogate (FE model of the MTHOTA surrogate of the thorax, which is validated with the human response corridors developed by Wayne State University’s researchers) was impacted with a typical foam nosed projectile at a speed of 90 meters per second. A collapsible Aluminum foil attached to the hollow foam nose of the projectile and impact simulations were carried out for different thicknesses of the foil (0.3 mm and 0.5 – 4.0 mm with an increment of 0.5 mm). To nullify the effect of the variation in the mass and also for effective comparison, impact speed was adjusted so that kinetic energy of the projectile remain same for all analyses. For the design of the collapsible mechanisms considered for the study, foil thickness less than 2 mm, though foiled structure got collapsed it didn’t absorb considerable amount of energy. More than 2 mm thickness, foil didn’t collapse properly and whole projectile acted as stiff/solid round and produced more injury. Dynamic force response, dynamic displacement response, effect of the aluminum foil on the thoracic injury in terms of VCmax etc., were presented in this paper

Male Grooming: An Ethnographic Research on Perception and Choice of Male Cosmetics

The purpose of this study is to explore male perceptions toward cosmetics and their product choice. Applying an ethnographic framework to this study, three males between the ages of 24-30 were interviewed through a series of 141 questions pertaining to their demographics, lifestyle, attitudes toward masculinity, skin care, grooming and cleaning behaviors. The results showed five overarching themes: (1) all of the participants had early experiences with personal care products, (2) the term masculinity was defined with terms such as calm and practical , (3) all participants looked up to their fathers as their key role models, (4) all participants valued loyal friendships, and (5) location convenience drives shopping for cosmetics - participants tend to only shop for cosmetics at a location where they are based at any given point in time, thereby implying an unwillingness to travel to a specialty store for purchasing grooming items. Managerial implications utilizing the results of this research are also discussed

Application of bifurcation methods for the prediction of low-speed aircraft ground performance

The design of aircraft for ground maneuvers is an essential part in satisfying the demanding requirements of the aircraft operators. Extensive analysis is done to ensure that a new civil aircraft type will adhere to these requirements, for which the nonlinear nature of the problem generally adds to the complexity of such calculations. Small perturbations in velocity, steering angle, or brake application may lead to significant differences in the final turn widths that can be achieved. Here, the U-turn maneuver is analyzed in detail, with a comparison between the two ways in which this maneuver is conducted. A comparison is also made between existing turn-width prediction methods that consist mainly of geometric methods and simulations and a proposed new method that uses dynamical systems theory. Some assumptions are made with regard to the transient behavior, for which it is shown that these assumptions are conservative when an upper bound is chosen for the transient distance. Furthermore, we demonstrate that the results from the dynamical systems analysis are sufficiently close to the results from simulations to be used as a valuable design tool. Overall, dynamical systems methods provide an order-of-magnitude increase in analysis speed and capability for the prediction of turn widths on the ground when compared with simulations. Nomenclature co = oleo damping coefficient, N s2 =m2 cz = tire vertical damping coefficient Fco = damping force in oleo due to the orifice,

Numerical continuation analysis of a dual-sidestay main landing gear mechanism

A model of a three-dimensional dual-sidestay landing gear mechanism is presented and employed in an investigation of the sensitivity of the downlocking mechanism to attachment point deflections. A motivation for this study is the desire to understand the underlying nonlinear behavior, which may prevent a dual-sidestay landing gear from downlocking under certain conditions. The model formulates the mechanism as a set of steady-state constraint equations. Solutions to these equations are then continued numerically in state and parameter space, providing all state parameter dependencies within the model from a single computation. The capability of this analysis approach is demonstrated with an investigation into the effects of the aft sidestay angle on retraction actuator loads. It was found that the retraction loads are not significantly affected by the sidestay plane angle, but the landing gear’s ability to be retracted fully is impeded at certain sidestay plane angles. This result is attributed to the landing gear’s geometry, as the locklinks are placed under tension and cause the mechanism to lock. Sidestay flexibilities and attachment point deflections are then introduced to enable the downlock loads to be investigated. The investigation into the dual sidestay’s downlock sensitivity to attachment point deflections yields an underlying double-hysteresis loop, which is highly sensitive to these deflections. Attachment point deflections of a few millimeters were found to prevent the locklinks from automatically downlocking under their own weight, hence requiring some external force to downlock the landing gear. Sidestay stiffness was also found to influence the downlock loads, although not to the extent of attachment point deflection

Insulin resistance and endometrial cancer risk: A systematic review and meta-analysis

Abstract Aim: It has been suggested that chronic hyperinsulinemia from insulin resistance is involved in the etiology of endometrial cancer (EC). We performed a systematic review and meta-analysis to assess whether insulin resistance is associated with the risk of EC. Methods: We searched PubMed-Medline, Embase, Scopus, and Web of Science for articles published from database inception through 30th September 2014. We included all observational studies evaluating components defining insulin resistance in women with and without EC. Quality of the included studies was assessed by NewcastleeOttawa scale. Randomeffects models and inverse variance method were used to meta-analyze the association between insulin resistance components and EC. Results: Twenty-five studies satisfied our inclusion criteria. Fasting insulin levels (13 studies, n Z 4088) were higher in women with EC (mean difference [MD] 33.94 pmol/L, 95% confi- dence interval [CI] 15.04e52.85, p Z 0.0004). No differences were seen in postmenopausal versus pre- and postmenopausal subgroup analysis. Similarly, non-fasting/fasting C-peptide levels (five studies, n Z 1938) were also higher in women with EC (MD 0.14 nmol/L, 95% CI 0.08e0.21, p < 0.00001). Homeostatic model assessment - insulin resistance (HOMA-IR) values (six studies, n Z 1859) in EC patients were significantly higher than in women without EC (MD 1.13, 95% CI 0.20e2.06, p Z 0.02). There was moderate-to-high heterogeneity among the included studies. Conclusion: Currently available epidemiologic evidence is suggestive of significantly higher risk of EC in women with high fasting insulin, non-fasting/fasting C-peptide and HOMAIR values.Revisión por pare