bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation on Response of an Aluminum Honeycomb Subjected to Hypervelocity Impacts using Lagrange and SPH for Numerical Modeling
Authors: Nitta Kumi , Higashide Masumi , Sueki Mirai , Takeba Atushi 
Published: July 2020

Abstract
Numerical modeling has been conducted with the commercial code AUTODYN 2D, using the Lagrange and Smooth Particle Hydrodynamics (SPH) processors. The numerical results are compared and discussed with the corresponding experimental results from the standpoint of assessing the protection of satellites against M/OD hypervelocity impacts. The material models used in the numerical simulation are also discussed, as well as a wide range of impact velocities, including shock-induced vaporization. The projectiles used to simulate M/OD consist of 100 μm to 1 mm diameter alumina with impact velocities of 2–15 km/s.
In order to assess the structural integrity of unmanned spacecraft subjected to the threat of hypervelocity impact by space debris, the numerical method was proposed mainly from the standpoint of material modeling suitable for extremely severe physical conditions such as high pressure, high temperature, high strain, and high strain rate, sometimes accompanied by shock-induced vaporization.
The numerical results adopting these material models were compared with the corresponding hypervelocity impact tests by using the two-stage light-gas gun at ISAS/JAXA. Although examples of the impacts on the aluminum honeycomb can be shown, it has been demonstrated that the numerical analysis can effectively simulate the overall corresponding experimental results.
We show the response of an aluminum honeycomb as derived from analysis of hypervelocity impact at 2 km/s to 15 km/s using the Lagrange and SPH processors. We also verified that the ballistic limit curve of an aluminum honeycomb panel is shown as a downward line using both processors, which is unlike the up and down ballistic limit curve of a Whipple shield.
The Role of Inclusions in the Failure of Boron Carbide Subjected to Impact Loading
Authors: Tonge Andrew L. , Schuster Brian E. 
Published: July 2020

Abstract
This work investigates the importance of the microstructure of boron carbide for initiating inelastic deformation under impact conditions. Simple loading resulting from a flyer plate impact geometry is used to illustrate the importance of microstructure for the well-controlled and easily instrumented experimental geometry. A second set of simulations is performed on a miniaturized impact geometry to investigate the importance of the microstructure for the early stages of semi-infinite penetration for impact velocities between 0.9 km/s and 1.9 km/s. The effect of the microstructure is more pronounced for the flyer plate impact geometry.
Modeling Hypervelocity Impact of Reinforced Carbon-Carbon Composite Thermal Protection System
Authors: Carpenter Alexander J. , Chocron Sidney , Walker James D. 
Published: July 2020

Abstract
Reinforced carbon-carbon (RCC) composite is used in applications where structural stiffness and strength must be maintained at very high temperatures that may reach 2000°C or more. For example, it was used on both the Space Shuttle’s nose cone and the leading edges of its wings. As exemplified by the Space Shuttle Columbia accident, the ability of these materials to survive impacts up to hypervelocity speeds can be critical for some applications. As computational modeling becomes an increasingly important component of the design process, the ability to accurately model RCC materials under impact conditions likewise becomes more and more important. This paper describes a computational model of the thermal protection used on the Space Shuttle orbiter. The model incorporates both the RCC comprising much of the protection system and its silicon carbide coating. The model was subjected to hypervelocity impacts with both steel and aluminum projectiles, and the results were compared to test data from the literature.
An Accurate SPH Scheme for Hypervelocity Impact Modeling
Authors: Collé Anthony , Limido Jérôme , Unfer Thomas , Vila Jean-Paul 
Published: July 2020

Abstract
We focus in this paper on the use of a meshless numerical method called Smooth Particle Hydrodynamics (SPH), to solve fragmentation issues as Hyper Velocity Impact (HVI). Contrary to classical grid-based methods, SPH does not need any opening criteria which makes it naturally well suited to handle material failure. Nevertheless, SPH schemes suffer from well-known instabilities questioning their accuracy and activating nonphysical processes as numerical fragmentation. Many stabilizing tools are available in the literature based for instance on dissipative terms, artificial repulsive forces, stress points or Particle Shifting Techniques (PST). However, they either raise conservation and consistency issues, or drastically increase the computation times. It limits then their effectiveness as well as their industrial application. To achieve robust and consistent stabilization, we propose an alternative scheme called γ -SPH-ALE. Firstly implemented to solve Monophasic Barotropic flows, it is secondly extended to the solid dynamics. Particularly, based on the ALE framework, its governing equations include advective terms allowing an arbitrary description of motion. Thus, in addition of accounting for a stabilizing low-Mach scheme, a PST is implemented through the arbitrary transport velocity field, the asset of ALE formulations. Through a nonlinear stability analysis, CFL-like conditions are formulated ensuring the scheme conservativity, robustness, stability and consistency. Besides, stability intervals are defined for the scheme parameters determining entirely the stability field. Its implementation on several test cases reveals particularly that the proposed scheme faithfully reproduces the strain localization in adiabatic shear bands, a precursor to failure. By preventing spurious oscillations in elastic waves and correcting the so-called tensile instability, it increases both stability and accuracy with respect to classical approaches.
Pagosa Simulation of Hypervelocity Impact and Fragmentation From Hypersonic Explosions
Authors: Ma Xia , Culp David , Smith Brandon 
Published: July 2020

Abstract
We use PAGOSA’s FLIP+MPM capability to simulate hypervelocity impact and fragmentation from hypersonic explosions. The scenario to be simulated involves a complex chain explosion from fragmentation impact which was caused by another explosion. The simulations also use the SURF model for shock to detonation transition (SDT) and the MATCH model for mechanical ignition and deflagration of high explosives. These models in PAGOSA working together are crucial for modeling complex system for real world applications. This shows the powerful modeling and predicting capability of PAGOSA that others cannot do. Since experimental data are not available for any complex scenario like this, we did verification and validation (V&V) in each separate steps, These include the fragmentation simulated by FLIP+MPM, the Shock to Detonation Transition (SDT) modeled by SURF and mechanical ignition and deflagration modeled by MATCH. PAGOSA is a shock hydrodynamics program developed at Los Alamos National Laboratory (LANL) for the study of high-speed compressible flow and high-rate material deformation. PAGOSA is a three-dimensional Eulerian finite difference code, solving problems with a wide variety of equations of state (EOSs), material strength, and explosive modeling options. It has high efficiency for simulations running on massively parallel supercomputers. It is a multi-material code using volume of fluid (VOF) interface reconstruction and second order fully explicit time integration. Standard von Neumann artificial viscosity is used. Newly added material point method (MPM) plus Fluid-Implicit Particle (FLIP) capability can simulate high-speed metal fragmentation.
Investigating Pressure Wave Impact on a Surrogate Head Model Using Numerical Simulation Techniques
Authors: Banton Rohan , Piehler Thuvan , Zander Nicole , Benjamin Richard , Duckworth Josh , Petel Oren 
Published: July 2020

Abstract
There is an urgent need to understand the mechanism leading to mild traumatic brain injury (mTBI) resulting from blast wave impact to the head. The recent conflicts in Iraq and Afghanistan have heightened the awareness of head impact injuries to military personnel resulting from exposure to blast waves [1, 2]. A blast wave generated in air is a by-product of the detonation of an explosive [3]. To date the mechanism resulting in mTBI from primary blast insult is still unclear.
Lateral meniscal allograft transplantation and stabilisation in a dog with stifle subluxation
Authors: Ridge Patrick Alan , Rial García Alba 
Published: July 2020

SUMMARYThis case describes the clinical features and the favourable clinical outcome after a lateral meniscal allograft transplant and stifle stabilisation in a dog that suffered a significant injury to its stifle, which included irreparable injury to the lateral meniscus, cranial cruciate ligament rupture and medial collateral rupture. The lateral meniscus was extensively damaged having avulsed from its peripheral attachments and with a radial tear across 70 per cent of its mid‐body. After four years, the owners reported that the dog continued with an active lifestyle and only occasionally required non‐steroidal anti‐inflammatory analgesics for sporadic episodes of mild lameness after vigorous exercise.
Verification of He-3 proportional counters’ fast neutron sensitivity through a comparison with He-4 detectors
Authors: Piscitelli Francesco , Mauri Giacomo , Laloni Alessio , Hall-Wilton Richard 
Published: July 2020

AbstractIn the field of neutron scattering science, a large variety of instruments require detectors for thermal and cold neutrons. Helium-3 has been one of the main actors in thermal and cold neutron detection for many years. Nowadays, neutron facilities around the world are pushing their technologies to increase the available flux delivered at the instruments; this enables a completely new science landscape. Complementary with the increasing available flux, a better signal-to-background (S/B) ratio enables to perform new types of measurements. For instance, in neutron reflectometry, the time resolution for kinetic studies is limited by the available S/B. An improved S/B opens the possibility of sub-second kinetic studies. To this aim, this manuscript re-examines the background sensitivity of today’s “gold standard” neutron detection. Fast neutrons and gamma rays are the main background species in neutron scattering experiments. The efficiency (sensitivity) of detecting fast neutrons, cosmic rays and gamma rays, for a Helium-3-based detector is studied here through the comparison with Helium-4 counters. The comparison with Helium-4 allows to separate the thermal (and cold) neutron from the fast neutron contributions in Helium-3-based counters which are otherwise entangled, verifying previous results from an indirect method. A relatively high sensitivity is found. Moreover, an estimate for the cosmic neutron fluence, also a source of background, at ground level at ESS is presented in this manuscript.
Patronage or Negotiation?
Authors: Mforbe Chiangong Pepetual 
Published: July 2020

Abstract
The collaboration between theatre directors and funding agencies can impede and/or promote the aesthetics and functionality of theatre performances, thus (dis)empowering the ordinary people. The paper, focusing on two performances, The Boomerang and Pamela’s Journal sponsored by the Fobang-Mundi Foundation and The Society for Women and AIDS in Africa-Cameroon (SWAA-C), explores the role of institutions and organisations that fund theatre projects in Africa to highlight the impact of patronage, specifically in contexts where the patron-artist relation is evoked. Questioning whether such projects could actually confer “power to the people,” depend on the negotiation skills and professionality of the theatre facilitator; the paper focuses on the beneficiaries of commissioned performances.
Transformative Power in Performance
Authors: Ngum Yvette 
Published: July 2020

Abstract
Despite the crucial role that performative arts play in enabling progressive transformation, education, healing and psychological protection for abuse on certain female bodies, often the intentions or agenda of such performances habitually outweighs the transformative potentials therein. In the context of this paper, my association with transformation is related to power in a performance that invites participants to reclaim the broken pieces of their lives as a form of agency. Tears in the Mirror, is based on my personal experience narrated in a performance-based project on sexual violence. In my position as the artist directing the play, I took down notes over a period of one-week rehearsal with the actor, representing my experience. The autoethnographic performance method for information sourcing was used with the actor. I used observation and discussion in the process and each stage reflected a continuing process of integrating the ‘doing’ of autoethnography with a critical reflection upon the subject matter. My findings showed that victims of sexual violence are more likely to identify with narratives of other victims during a performance. This is because in viewing the image of the actor on stage one is simultaneously viewing the self in the mirror of the other.
Diagnosis of tibiofibular syndesmosis instability in Weber type B malleolar fractures
Authors: Huang Qiang , Cao Yongxing , Yang Chonglin , Li Xingchen , Xu Yangbo , Xu Xiangyang 
Published: July 2020

Objective This study was performed to analyze the clinical value of X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) examinations for the diagnosis of distal tibiofibular syndesmosis injuries in Weber type B ankle fractures with reference to the ankle arthroscopic findings. Methods This retrospective clinical study involved 52 patients with type B ankle fractures from August 2014 to January 2018. We analyzed the patients’ preoperative imaging data and judged the stability of the distal tibiofibular syndesmosis using X-ray, CT, and MRI examinations. We also evaluated the syndesmosis stability with arthroscopy both statically and dynamically. Results With the arthroscopic findings as the standard, the sensitivity of X-ray for diagnosing syndesmosis instability was 52.8%, the specificity was 100%, and the diagnostic efficiency was 67.3%. The sensitivity of CT for diagnosing syndesmosis instability was 77.8%, the specificity was 100%, and the diagnostic efficiency was 84.6%. The sensitivity of MRI for diagnosing syndesmosis instability was 100%, the specificity was 81.3%, and the diagnostic efficiency was 94.2%. Conclusion This study suggests that an arthroscopic examination may be recommended when the X-ray or CT features are different from the MRI findings while diagnosing tibiofibular syndesmosis instability in Weber type B malleolar fractures.
PM2.5 exposure induced renal injury via the activation of the autophagic pathway in the rat and HK-2 cell
Authors: Huang Xiaoliu , Zhou Zhitong , Liu Xinwen , Li Jue , Zhang Lijuan 
Published: July 2020

Abstract
Background
Exposure to airborne fine particulate matter (PM2.5) has been declared to be harmful to human kidney. However, whether activation of the autophagic pathway plays key roles in the nephrotoxicity caused by PM2.5 exposure is still poorly understood. The aim of this study was to explore the mechanism of kidney damage after PM2.5 exposure in vivo and in vitro.

Results
In the present study, statistically significant alterations in water intake, urine flow rate and mean blood pressure were observed between the concentrated PM2.5 (PM2.5) group and the filtered air (FA) group. Exposed animals showed severe edema of renal tubular epithelial cells, capillary congestion, reduction of the glomerular urinary space and early pro-fibrotic state. Moreover, significant increases in the levels of early kidney damage markers were observed in the exposed rats and these animals exhibited more apoptosis rate in kidney cells. In addition, PM2.5 exposure activated the autophagic pathway, as evidenced by LC3-I to LC3-II conversion, activation of P62 and beclin-1. All of these effects are in concurrence with the presence of more autophagosomes both in vivo and in vitro after PM2.5 exposure.

Conclusions
Taken together, our findings indicated that PM2.5 induced renal function impairment via the activation of the autophagic pathway in renal tubular epithelial cells.
Modeling blood–brain barrier pathology in cerebrovascular disease in vitro: current and future paradigms
Authors: Andjelkovic Anuska V. , Stamatovic Svetlana M. , Phillips Chelsea M. , Martinez-Revollar Gabriela , Keep Richard F. 
Published: July 2020

AbstractThe complexity of the blood–brain barrier (BBB) and neurovascular unit (NVU) was and still is a challenge to bridge. A highly selective, restrictive and dynamic barrier, formed at the interface of blood and brain, the BBB is a “gatekeeper” and guardian of brain homeostasis and it also acts as a “sensor” of pathological events in blood and brain. The majority of brain and cerebrovascular pathologies are associated with BBB dysfunction, where changes at the BBB can lead to or support disease development. Thus, an ultimate goal of BBB research is to develop competent and highly translational models to understand mechanisms of BBB/NVU pathology and enable discovery and development of therapeutic strategies to improve vascular health and for the efficient delivery of drugs. This review article focuses on the progress being made to model BBB injury in cerebrovascular diseases in vitro.
Nonlinear eigenvalue problems for nonhomogeneous Leray–Lions operators
Authors: Abdelwahed Mohamed , Chorfi Nejmeddine 
Published: July 2020

AbstractThis paper deals with the mathematical analysis of a class of nonlinear eigenvalue problems driven by a nonhomogeneous differential operator. We are concerned both with the coercive and the noncoercive (and nonresonant) cases, which are in relationship with two associated Rayleigh quotients. The proof combines critical point theory arguments and the dual variational principle. The arguments developed in this paper can be extended to other classes of nonlinear eigenvalue problems with nonstandard growth.
Increase of vancomycin-resistant Enterococcus faecium strain type ST117 CT71 at Charité - Universitätsmedizin Berlin, 2008 to 2018
Authors: Weber Anna , Maechler Friederike , Schwab Frank , Gastmeier Petra , Kola Axel 
Published: July 2020

Abstract
Background
In addition to an overall rise in vancomycin-resistant Enterococcus faecium (VREfm), an increase in certain strain types marked by sequence type (ST) and cluster type (CT) has been reported in Germany over the past few years. Outbreak analyses at Charité - Universitätsmedizin Berlin revealed the frequent occurrence of VREfm ST117 CT71 isolates in 2017 and 2018. To investigate whether ST117 CT71 have emerged in recent years or whether these strains have been circulating for a longer time, we retrospectively analyzed non-outbreak strains that occurred between 2008 and 2018 to identify frequent STs and CTs.

Methods
In total, 120 VREfm isolates obtained from clinical and surveillance cultures from the years 2008, 2013, 2015, and 2018 were analyzed. Thirty isolates per year comprising the first 7–8 non-outbreak isolates of each quarter of the respective year were sequenced using whole genome sequencing. MLST and cgMLST were determined as well as resistance genes and virulence factors. Risk factors for VREfm ST117 were analyzed in a multivariable analysis with patient characteristics as possible confounders.

Results
The percentage of VREfm of type ST117 increased from 17% in 2008 to 57% in 2018 (p = 0.012). In 2008, vanA genotype accounted for 80% of all ST117 isolates compared to 6% in 2018. VanB CT71 first appeared in 2018 and predominated over all other ST117 at 43% (p < 0.0001).
The set of resistance genes (msrC, efmA, erm(B), dfrG, aac(6′)-Ii, gyrA, parC and pbp5) and virulence factors (acm, esp, hylEfm, ecbA and sgrA) in CT71 was also found in other ST117 non-CT71 strains, mainly in CT36. The study population did not differ among the different calendar years analyzed in terms of age, gender, length of stay, or ward type (each p > 0.2).

Conclusion
This study revealed an increase in ST117 strains from 2008 to 2018, accompanied by a shift toward CT71 strains with the vanB genotype in 2018. We did not detect resistance or virulence traits in CT71 that could confer survival advantage compared to other CTs among ST117 strains. To date, it is not clear why ST117 and in particular strain type ST117 CT71 predominates over other strains.
Efficacy of transmastoidal galvanic stimulation on recovery outcomes in patients with unilateral peripheral vestibular disorders: a randomized controlled trial
Authors: Ahmed Reham Ali Mohamed Ali , Fahmy Ebtesam Mohamed , Awad Amina Mohamed , Hamdy Mona Mohamed , Shaker Hussein Ahmed Abd Rahman 
Published: July 2020

Abstract
Background
Peripheral vestibular disorders are common disorders among population with increased prevalence with age advancement, manifested by balance disorders and postural instability that negatively affect daily activities and social participation.

Objectives
To investigate the effect of transmastoidal galvanic stimulation added to a designed vestibular rehabilitation program on recovery outcomes in Egyptian patients with unilateral peripheral vestibular disorders.

Subjects and methods
Forty patients (from both sexes) diagnosed with unilateral peripheral vestibular weakness were evenly and randomly designated into two groups: study and control groups. The study group received transmastoidal galvanic stimulation, in addition to a vestibular rehabilitation program, whereas control group undergone vestibular rehabilitation program only. Treatment sessions were conducted three times weekly for four successive weeks. Assessment of vestibular canal weakness was carried out using videonystagmography, postural stability using computerized posturography, while participation in daily activities was carried out using Vestibular Disorders Activities of Daily Living Scale (VADL). All assessment measures were carried out pre- and post-treatment.

Results
Study group showed improvement of post-treatment scores of canal weakness, postural stability parameters, and VADL scale in reverse to control group that showed improvement of scores of preference and VADL only. A statistically significant difference was found between both groups in post-treatment scores of canal weakness, total equilibrium composite, and vestibular component with more improvement in the study group.

Conclusion
Adding transmastoidal galvanic stimulation to vestibular rehabilitation exercises for unilateral peripheral vestibular disorders improves the recovery outcomes of vestibular canal weakness, equilibrium, and vestibular components of postural stability.

Trial registration
Clinical trials identification number (NCT04010435). Registered 7 March 2019—retrospectively registered, https://register.clinicaltrials.gov/prs/app/action/LoginUser?ts=1&cx=-jg9qo4