bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wear behavior of TC4 titanium alloy and 2205 stainless steel friction pair in different media
Authors: Wang C P , Wu X B , Xiao Y X , Song D W , Wang H Z , Wang S H 
Published: March 2020

Abstract
In order to choose the material of high-pressure pump in seawater desalination, the friction pair of TC4 titanium alloy and 2205 duplex stainless steel was studied in detail. Friction and wear tests were carried out under dry friction, pure water, and seawater media. The friction coefficient and wear extent of friction pair were obtained quantitatively, and the surface topography of friction samples was analyzed. The results showed that the abrasion of 2205 stainless steel and TC4 titanium alloy in seawater was less than in pure water and air/dry friction due to the lubrication effect of seawater medium. The abrasion resistance of 2205 stainless steel was better than that of TC4 titanium alloy. Compared with the rotating speed, the load has little effect on the friction coefficient.
Effect of carbon source on the synthesis of ZrB2–SiC composite powders
Authors: Lian X Q , Hua X H , Wang X G , Deng L R , Zhang L 
Published: March 2020

Abstract
This study is aimed to synthesize ZrB2–SiC composite powders by boro-carbothermal reduction of zircon using two different carbon sources, namely expanded graphite and carbon black. The effect of carbon sources on the phase composition and microstructure of composite powders was studied using an X-ray diffractometer, a scanning electron microscope, and an energy spectrum analyzer. Pure-phase ZrB2–SiC composite powders were prepared in 2 h at 1550 and 1500 °C 1500 °C using expanded graphite and carbon black, respectively. In the former case, anisotropic ZrB2–SiC composite powders were synthesized. Their ZrB2phase grains had an average diameter of 2.0 μm and regular hexagonal shape, while SiC phase grains were whisker-shaped, had an average diameter of 0.15 μm and aspect ratio exceeding 20. For carbon black, finer ZrB2grains and shorter rod-shaped SiC grains were obtained.
Hot deformation behavior and processing map of Mg-12Gd-1MM-0.6Zr magnesium alloy
Authors: Li B B , Shi G L , Zhang K , Wang K K , Li X G , Li Y J , Ma M L , Yuan J W 
Published: March 2020

Abstract
The hot deformation behavior of Mg-12Gd-1MM-0.6Zr (wt.%) magnesium alloy was tested by Gleeble-1500D hot simulator with reduction of 60% and strain rates from 0.001 to 1 s−1 at the temperature range from 753 to 793 K. The results show that the flow stress is influenced by both, temperatures and strain rates. At constant temperatures, flow stress is increased with strain rate, while at constant strain rates, it decreased with temperature. The constitutive equation of Mg-12Gd-1MM-0.6Zr alloy during hot compression was constructed by the linear regression analysis. Average activation energy and stress exponent were 227.94 kJ/mol and 2.87, respectively. The processing map was plotted and analyzed via the dynamic material model. The most proper ranges for hot deformation temperature and strain rate were found to be 763 to 783 K and 0.01 to 0.1 s−1, respectively.
Comparative oxidation study of aviation lubrication oil
Authors: Ma J , Sun Y B , Jiang X F , Fei Y W , Ruan S J , Li L B 
Published: March 2020

Abstract
The kinematic viscosity, lubricity, acid number of 928 and 50-1-4Φ aviation lubrication oils are investigated in this paper. Oil samples were oxidized at 150 and 175°C for 120 h to evaluate their performance variation. The results suggest that 928 lubrication oil is easily oxidized and generates acidic products, which increase its acid number. The comparative analysis revealed that 928 lubrication oil tends to react in oxidizing atmosphere, which increases its viscosity, acid number, and weight-bearing performance. Meanwhile, wear scar diameters of both oxidized oil samples were found to be nearly the same.
Synchrotron radiation imaging and characterization of creep cracks in 2219 aluminum alloy
Authors: Xu F M , Guo Q , Xu Y X , Dong W , Li T T , Fu Y N 
Published: March 2020

Abstract
Aluminum alloys are lucrative aerocraft materials due to their high-temperature performance, which involves creep crack propagation. However, it is difficult to acquire three-dimensional morphology, volume, and quantity through traditional imaging and characterization techniques, as metallic alloys are optically opaque. The development of synchrotron radiation X-ray tomography has facilitated the study of creep crack propagation. In this study, samples obtained by an interruption experiment were subjected to X-ray tomography observation. Based on reconstruction and visualization software analysis, cracks were first formed inside the material and then propagated via the growth and connection of creep voids. While propagating forward, the cracks also propagated toward the material surface, with the inside of the material propagating more than the surface of the material. When the main crack propagated, irregularly shaped microcracks and large independent branch cracks were generated, promoting the propagation of the main crack.
An explicit high-efficiency algorithm for simulating high-cycle fatigue behavior of metals
Authors: Wang S Y , Zhan L , Xu Z H , Xi H F , Xiao H 
Published: March 2020

Abstract
This article presents a direct and efficient algorithm for simulating high-cycle fatigue failure effects within the framework of a recently proposed elastoplastic model, in which fatigue failure effects of metals are incorporated as inherent constitutive features. Toward bypassing very time-consuming procedures in conducting numerical integrations of the elastoplastic rate equations for extremely large number of loading cycles, from the new model it is possible to derive an explicit expression for the fatigue life directly in terms of the stress amplitude. Numerical examples show that the new algorithm thus established is much more efficient than usual direct numerical procedures and that is particularly the case in simulating fatigue failure effects with very high cycle number.
Research of microscale silver particle paste on Al2O3, pre-dried dielectric layer and pre-fired dielectric layer substrate by a co-firing process
Authors: Tongxin Liu , Jian Wan , Yucai You , Ningze Zhuo , Haibo Wang 
Published: March 2020

Abstract
In this paper, the silver paste was prepared by highly dispersed spherical silver powders with an average particle size of 0.85 um. The silver conductive thick films were printed on Al2O3 and dielectric layer by screen-printing, the dielectric layer had been heat-treated differently, one was dried, the other fired. The corresponding sintering behaviors, electrical and mechanical properties of silver films were investigated systematically. Besides, we made a chip resistor to test performance. The results show that the silver conducting film on fired dielectric is compact, uniform and defect-free, the resistivity and adhesion are 2.54 uΩ·cm and 20.3 N mm−2 respectively. With the increase of sintering times, the conductivity of silver films on the fired dielectric layer increases first and then decreases, while the adhesion increases continuously. We proposed that the diffusion quantity of glasses from the dielectric layer to the surface was the key step in the period of the properties of silver films. The silver film on the fired dielectric layer has better applications in the high current chip resistors.
Thermal response of carbon fiber reinforced epoxy composites irradiated by thermal radiation
Authors: Gao Yinjun , Gao Lihong , Ma Chen , Ma Zhuang , Zhang Xianghua , Peng Guoliang , Tian Zhou 
Published: March 2020

Abstract
Although carbon fiber reinforced epoxy composites (CF/EP) have been widely used in many fields, it is still unknown if such composites could be used in extreme environments exposed to high-intensity thermal radiation that could result in severe damage to materials. In this case, CF/CP has been prepared through thermocompression method and the thermal radiation experiment has been designed and performed. The obtained results show that the parameters including irradiation power density and irradiation time directly affect the damage degree. After irradiation with 4–6 W cm−2 of thermal radiation, decomposition occurred in all CF/EP composites. In addition, the numerical simulation method was used to calculate the effect process, and the results showed that when the thermal radiation coefficient was 0.88, the calculated temperature history was consistent with that of the experiment. After irradiated at 6 W cm−2 for 30 s, the decomposition thickness reaches to 0.7 mm, indicating the high-intensity thermal radiation has caused an obvious effect on CF/EP.
Effect of V2O5 on crystallization tendency and chemical durability of Mo-bearing aluminoborosilicate glass
Authors: Lian Qihui , Zhang Xingquan , Ji Hongjia , Yu Pengpeng , Guo Xiaofeng , Wan Wei , Liu Haifeng , Zheng Kui , Zhu Yongchang , Wang Haibin , Huo Jichuan 
Published: March 2020

Abstact
The effect of V2O5 addition on molybdates crystallization tendency, glass structure and chemical durability of aluminoborosilicate glass belonging to SiO2-B2O3-CaO-Na2O-Al2O3-MoO3 system has been studied. The results confirm that V2O5 addition can effectively suppress the crystallization tendency of powellite and enhance the molybdenum solubility in the glass. The MoO3 solubility limit is found to be 2.8 mol% in the V2O5-containing aluminoborosilicate glass. Raman results reveal that V2O5 addition seems to modify the local structural environment of isolated MoO4 units and increase their chemical disorder in the glass, which is favored for molybdenum incorporation in the glass. The molar volume and glass transition temperature of samples are found to depend on V2O5 content. Product consistency test (PCT) results show that the normalized leaching rates of the V2O5-containing aluminoborosilicate glass maintain at a fairly low level compared with standard borosilicate glassy waste form.
Ambient temperature fluctuations exhibit inverse-cubic spectral behavior over time scales from a minute to a day
Authors: Lowen Steven B , Mohan Nishant , Teich Malvin Carl 
Published: March 2020

Abstract
Ambient temperature fluctuations are of importance in a wide variety of scientific and technological arenas. In a series of experiments carried out in our laboratory over an 18-month period, we discovered that these fluctuations exhibit 1/f
3 spectral behavior over the frequency range 1.0 × 10−5 ≤ f ≤ 2.5 × 10−2 Hz, corresponding to 40 s ≤ T

f
≤ 1.2 d, where T

f
= 1/f. This result emerges over a broad range of conditions. For longer time periods, 1.2 < T

f
≤ 11.6 d, corresponding to the frequency range 1.0 × 10−6 ≤ f < 1.0 × 10−5 Hz, we observed 1/f
2 spectral behavior. This latter result is in agreement with that observed in data collected at European weather stations. Scalograms computed from our data are consistent with the periodograms.
Reversible and concerted atom diffusion on supported gold nanoparticles
Authors: Liu Pei , Madsen Jacob , Schiøtz Jakob , Wagner Jakob Birkedal , Hansen Thomas Willum 
Published: March 2020

Abstract
Traditionally, direct imaging of atom diffusion is only available by scanning tunneling microscopy and field ion microscopy on geometry-constrained samples: flat surfaces for STM and needle tips for FIM. Here we show time-resolved atomic-scale HRTEM investigations of CeO2-supported Au nanoparticle surfaces to characterize the surface dynamics of atom columns on gold nanoparticles. The observed surface dynamics have been categorized into four types: layer jumping, layer gliding, re-orientation and surface reconstruction. We successfully captured atoms moving in a concerted manner with a time resolution of 0.1 s. A quantitative approach for measuring the dynamics in various gaseous surroundings at elevated temperatures is presented. An approach for measuring quantitative electron beam effects on the surface dynamics is presented by counting atom column occupation as a function of time under a range of dose rates in high vacuum.
Risk From Within: Intraminority Gay Community Stress and Sexual Risk-Taking Among Sexual Minority Men
Authors: Burton Charles L , Clark Kirsty A , Pachankis John E 
Published: March 2020

Abstract

Background
Sexual minority men remain highly impacted by the human immunodeficiency virus (HIV) with social stress being a clear predictor of their risk for infection. The past several decades of stress research regarding sexual minority men’s HIV-risk behaviors has almost exclusively focused on the influence of stress emanating from outside the gay community (e.g., stigma-related stress, or minority stress, such as heterosexist discrimination). However, recent evidence suggests that sexual minority men also face stress from within their own communities.

Purpose
We sought to examine whether stress from within the gay community, or intraminority gay community stress, might influence sexual minority men’s risk behaviors, including HIV-risk behaviors, over-and-above more commonly examined stressors affecting this risk.

Methods
We tested whether intraminority gay community stress was associated with sexual minority men’s HIV-risk behaviors in a large national survey of sexual minority men (Study 1), and experimentally tested intraminority gay community stress’s impact on behavioral risk-taking and attitudes toward condom use (Study 2).

Results
Self-reported exposure to intraminority gay community stress was positively associated with HIV-risk behaviors when accounting for the effects of several commonly examined minority stressors and general life stress (Study 1). Participants who were rejected from an online group of other sexual minority men evidenced greater risk-taking in a subsequent task and reported fewer benefits of condom use than participants who were accepted by the online group, when accounting for state affect (Study 2).

Conclusions
Sexual minority men’s experiences of stress and rejection stemming from their own community may be an important and overlooked predictor of HIV infection and transmission.
Use of prescription medication in the last years of life: a population-based comparison of two oldest old Danish birth cohorts born 10 years apart
Authors: Pedersen Jacob Krabbe , Jensen Troels Mygind , Waldorff Frans Boch , Søndergaard Jens , Christensen Kaare 
Published: March 2020

Abstract

Introduction
Age limits for diagnostics and treatments have been largely removed and replaced by an active diagnostic and treatment practice among the oldest old and has led to concerns about potential overtreatment during the last years of life.

Methods
Use of prescription medication in the last years of life was assessed from 1995 to 2012 for the entire 1905 and 1915 Danish birth cohorts using nationwide register data. Medication use was quantified as the number different pharmacy-redeemed drugs during 120 days up to a given date.

Results
For both cohorts, prescription medication use increased with proximity to death and calendar year, while age at death had little impact; use in the 1915 cohort was markedly higher than in the 1905 cohort. Average number of prescription medications varied from below 3 to above 9 depending on age, calendar year and proximity to death. From 1995 to 2005, average number of prescription medications for a 90-year-old person in the last month of life increased from 6.0 to 8.7. Out of 90-year-old persons dying in 2005, 82% were exposed to polypharmacy, up from 63% in 1995.

Conclusions
Prescription medication use accelerates throughout the last of years life among two Danish oldest old cohorts born 10 years apart, with substantially larger use in the most recent cohort. This pattern suggests an increase in drug prescribing regimens in the period 1995–2012, reinforcing the need for evidence-based guidelines on medications in the particularly vulnerable population of the oldest old patients in their last years of life.
The Behavior Rating Inventory of Executive Function®-Adult Version is Related to Emotional Distress, Not Executive Dysfunction, in a Veteran Sample
Authors: Shwartz Susan K , Roper Brad L , Arentsen Timothy J , Crouse Ellen M , Adler Marcy C 
Published: March 2020

Abstract

Objective
In three studies, we explore the impact of response bias, symptom validity, and psychological factors on the self-report form of the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) and the relationship between self-reported executive functioning (EF) and objective performance.

Method
Each study pulled from a sample of 123 veterans who were administered a BRIEF-A and Minnesota Multiphasic Personality Inventory-2 (MMPI-2) during a neuropsychological evaluation. Participants were primarily middle-aged, and half carried a mood disorder diagnosis. Study 1 examined group differences in BRIEF-A ratings among valid, invalid, and indeterminate MMPI-2 responders. Analyses were conducted to determine the optimal cut-score for the BRIEF-A Negativity Validity scale. In Study 2, relationships were explored among MMPI-2-RF (restructured form) Restructured Clinical (RC) scales, somatic/cognitive scales, and the BRIEF-A Metacognition Index (MI); hierarchical analyses were performed to predict MI using MMPI-2-RF Demoralization (RCd) and specific RC scales. Study 3 correlated BRIEF-A clinical scales and indices with RCd and an EF composite score from neuropsychological testing. Hierarchical analyses were conducted to predict BRIEF-A clinical scales.

Results
Invalid performance on the MMPI-2 resulted in significantly elevated scores on the BRIEF-A compared to those with valid responding. A more stringent cut-score of ≥4 for the BRIEF-A Negativity scale is more effective at identifying invalid symptom reporting. The BRIEF-A MI is most strongly correlated with demoralization. BRIEF-A indices and scales are largely unrelated to objective EF performance.

Conclusions
In a veteran sample, responses on the BRIEF-A are most representative of generalized emotional distress and response bias, not actual EF abilities.
Efficacy of Ultrasound for Localized Fat Treatment on Clinical and Psychological Outcomes: A Randomized, Single-Blind, Placebo-Controlled Clinical Trial
Authors: Lopes Jaqueline Santos Silva , dos Santos Sinara Pereira , de Almeida Lívia Maria Borges , Kayser Ariadne Pereira , Reis Elcilene Franciele Oliveira , de Oliveira Ketelly Alves , do Amaral Queiroz Mirella Carina , da Silva Luaneia Pereira , Marques Ana Beatriz Ferreira , da Silva Borges Bethânia Monteiro , de Almeida Aline Castilho 
Published: March 2020

Abstract

Background
The use of ultrasound for localized fat treatment on possible psychological influences is little explored to date. Therefore, it is relevant to elaborate studies that include a placebo group in order to measure the real effects of the exclusive application of ultrasound.

Objectives
To verify the influence of ultrasound application for localized fat treatment on clinical, functional, and psychological outcomes.

Methods
Thirty female participants who were candidates for localized abdominal fat treatment were included and randomly divided into three groups: control (CG, n = 10), experimental (EG, n = 10), and placebo (PG, n = 10). The CG did not receive any intervention. The EG received 10 ultrasound sessions for 20 minutes. For the PG, ultrasound was also applied for 20 minutes, but with zero intensities. Anthropometric assessment, cardiovascular parameters, circumference measurements, photography, endurance test, and subjective questionnaires were performed before and after the treatment protocols.

Results
The EG photographs show an improvement of 60% in the visual appearance. Regarding the other analyzed outcomes, no statistically significant differences were found between moments and groups (P &gt; 0.05).

Conclusions
Pretreatment and posttreatment photographs analysis demonstrate visual improvement in the appearance of abdominal localized fat in the EG. However, ultrasound application, when compared with CG and PG, is not a superior method for improving clinical, functional, and psychological parameters.

Level of Evidence: 2
Inference under unequal probability sampling with the Bayesian exponentially tilted empirical likelihood
Authors: Yiu A , Goudie R J B , Tom B D M 
Published: March 2020

SummaryFully Bayesian inference in the presence of unequal probability sampling requires stronger structural assumptions on the data-generating distribution than frequentist semiparametric methods, but offers the potential for improved small-sample inference and convenient evidence synthesis. We demonstrate that the Bayesian exponentially tilted empirical likelihood can be used to combine the practical benefits of Bayesian inference with the robustness and attractive large-sample properties of frequentist approaches. Estimators defined as the solutions to unbiased estimating equations can be used to define a semiparametric model through the set of corresponding moment constraints. We prove Bernstein–von Mises theorems which show that the posterior constructed from the resulting exponentially tilted empirical likelihood becomes approximately normal, centred at the chosen estimator with matching asymptotic variance; thus, the posterior has properties analogous to those of the estimator, such as double robustness, and the frequentist coverage of any credible set will be approximately equal to its credibility. The proposed method can be used to obtain modified versions of existing estimators with improved properties, such as guarantees that the estimator lies within the parameter space. Unlike existing Bayesian proposals, our method does not prescribe a particular choice of prior or require posterior variance correction, and simulations suggest that it provides superior performance in terms of frequentist criteria.
Is There an Association Between COVID-19 Mortality and the Renin-Angiotensin System? A Call for Epidemiologic Investigations
Authors: Hanff Thomas C , Harhay Michael O , Brown Tyler S , Cohen Jordana B , Mohareb Amir M 
Published: March 2020

Abstract
Mortality from coronavirus disease 2019 (COVID-19) is strongly associated with cardiovascular disease, diabetes, and hypertension. These disorders share underlying pathophysiology related to the renin-angiotensin system (RAS) that may be clinically insightful. In particular, activity of the angiotensin-converting enzyme 2 (ACE2) is dysregulated in cardiovascular disease, and this enzyme is used by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to initiate the infection. Cardiovascular disease and pharmacologic RAS inhibition both increase ACE2 levels, which may increase the virulence of SARS-CoV-2 within the lung and heart. Conversely, mechanistic evidence from related coronaviruses suggests that SARS-CoV-2 infection may downregulate ACE2, leading to toxic overaccumulation of angiotensin II that induces acute respiratory distress syndrome and fulminant myocarditis. RAS inhibition could mitigate this effect. With conflicting mechanistic evidence, we propose key clinical research priorities necessary to clarify the role of RAS inhibition in COVID-19 mortality that could be rapidly addressed by the international research community.