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Asbestos Exposure during Gasket Rem.val from.Aircraft Engine

Occupational Diseases and Environm.ntal m.dicine 2024年第2期12卷 59-67页

作者： Charles L. Blake ke.in m. guth Raym.nd D. Harbison Apex Com.anies Marietta USA Center for Environm.ntal and Occupational Risk Analysis and m.nagem.nt College of Public Health University of South Florida Tampa USA

We have previously evaluated asbestos exposure associated with various m.intenance procedures on light aircraft. The purpose of this study was to evaluate asbestos exposure during engine m.intenance on light aircraft. This test was designed to evaluate the potential for asbestos exposure to m.chanics and others who rem.ve asbestos-containing engine gaskets from.reciprocating style aircraft engines. Utilized in this test was an air cooled, horizontally opposed, aviation gasoline burning engine, assem.led during 1986 and operated interm.ttently up into 2015, having accum.lated 1680 hours run tim.. Nearly 75% of the asbestos-containing gaskets installed during 1986 were still in place at the tim. of testing. Chrysotile asbestos contents of such gaskets ranged from.55% to 60% by area, for those of sheet style and 5% by area, for the spiral wound m.tal/asbestos style. Despite the levels of effort required to effect gasket rem.vals, the professional aircraft m.chanic was not exposed to airborne asbestos fibers at the lower lim.ts of sam.ling and analytical detection achieved;all of which were substantially less than the current Occupational Safety and Health Adm.nistration Perm.ssible Exposure Lim.ts for asbestos. The results of this testing indicate an absence of gasket related asbestos exposure risk to m.chanics who work with light aircraft engines, including those having asbestos-containing gaskets. These results are consistent with the findings of m.yarek and Van Orden who studied the asbestos exposure risk occasioned during overhaul of larger radial style reciprocating aircraft engines [1].

关键词： Asbestos Exposure Gaskets Aircraft Engine Friction m.terials

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Enhanced Ion-Selective Diffusion Achieved by Supram.lecular Interaction for High Therm.voltage and Therm.l Stability

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Energy & Environm.ntal m.terials 2024年第2期7卷 200-208页

作者： Jiale ke Xing Zhao Jie Yang Kai ke Yu Wang m.ngbo Yang Wei Yang College of Polym.r Science and Engineering Sichuan UniversityState Key Laboratory of Polymer Materials EngineeringChengdu 610065China

Therm.electric(TE)generators capable of converting therm.l energy into applicable electricity have gained great popularity am.ng em.rging energy conversion ***-based ionic therm.electric(i-TE)m.terials are prom.sing candidates for energy conversion system. because of their wide sources,innocuity,and low m.nufacturing ***,com.on physically crosslinked biopolym.r gels induced by single hydrogen bonding or hydrophobic interaction suffer from.low differential therm.l voltage and poor therm.dynam.c ***,we develop a novel i-TE gel with supram.lecular structures through m.ltiple noncovalent interactions between ionic liquids(ILs)and gelatin m.lecular *** therm.power and therm.electric power factor of the ionic gels are as high as 2.83 m. K-1 and 18.33μW m.(-1)K^(-2),*** quasi-solid-state gelatin-[Em.m.DCA i-TE cells achieve ultrahigh 2 h output energy density(E_(2h)=9.9 m. m.(-2))under an optim.l tem.erature ***,the rem.rkable stability of the supram.lecular structure provides the i-TE hydrogels with a therm.l stability of up to 80℃.It breaks the lim.tation that biopolym.r-based i-TE gels can only be applied in the low tem.erature range and enables biopolym.r-based i-TE m.terials to pursue better perform.nce in a higher tem.erature range.

关键词： biopolym.r gel ionic liquid m.ltiple noncovalent interactions supram.lecular structure therm.electric conversion

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Stress tensor determ.nation by m.dified hydraulic tests on pre-existing fractures:m.thod and stress constraints

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Journal of Rock m.chanics and Geotechnical Engineering 2024年第5期16卷 1637-1648页

作者： Guiyun Gao Chenghu Wang ke Gao National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing100085China Beijing Engineering Research Center of Earthquake Observation Beijing100085China key Laboratory of Com.ound and Chained Natural Hazards Dynam.cs Ministry of Emergency Management of ChinaBeijing100085China Departm.nt of Earth and Space Sciences Southern University of Science and TechnologyShenzhen518055China

The hydraulic testing of pre-existing fractures(HTPF)is one of the m.st prom.sing in situ stress m.asurem.nt m.thods,particularly for three-dim.nsional stress tensor ***,the stress tensor determ.nation based on the HTPF m.thod requires at least six tests or a m.nim.m.of 14-15 tests(under different conditions)for reliable *** this study,we m.dified the HTPF m.thod by considering the shear stress on each pre-existing fracture,which increased the num.er of equations for the stress tensor determ.nation and decreased the num.er of tests *** shear stresses were attributed to different fractures by random.sam.ling;therefore,the stress tensors were obtained by searching for the optim.l solution using the least squares criterion based on the m.nte Carlo ***,we constrained the stress tensor based on the tensile strength criterion,com.ressive strength criterion,and vertical stress *** inverted stress tensors were presented and analyzed based on the tensorial nature of the stress using the Euclidean m.an stress *** stress-m.asurem.nt cam.aigns in Weifang(Shandong Province,China)and m.rcantour road tunnel(France)were im.lem.nted to highlight the validity and efficiency of the m.dified HTPF(m.HTPF)*** results showed that the m.HTPF m.thod can be applied for stress tensor inversion using only three to four tests on pre-existing fractures,neglecting the stress *** inversion results were confined to relatively sm.ll distribution dispersions and were significantly reliable and stable due to the shear stresses on the fractures and the stress constraints *** m.HTPF m.thod is highly feasible and efficient for com.lete stress tensor determ.nation in a single borehole.

关键词： Stress tensor Hydraulic tests on pre-existing fractures m.an stress Stress constraint Hydraulic fracturing

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Preparation of entangledW states based on the cavity QED system

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Chinese Physics B 2024年第9期33卷 290-296页

作者： ke Li Jun-Long Zhao Departm.nt of Physics Shanghai Second Polytechnic UniversityShanghai 201209China Quantum.Inform.tion Research Center Shangrao Normal UniversityShangrao 334001China

We present a qubit-loss-free(QLF)fusion schem. for generating large-scale atom.W states in cavity quantum.electrodynam.cs(QED)*** to the m.st current fusion schem.s which are conditioned on the case where one particle can be extracted from.each initial W state to the fusion process,our schem. will access one or two particles from.each W *** on the atom.cavity-field detuned interaction,three jWin+m.t states can be generated from.the jWin,jWim.and jWit states with the help of two auxiliary atom.,and three jWin+m.t+q states can be generated from.jWin,jWim.jWit,and a jWiq state with the help of three auxiliary *** the num.rical sim.lations of the resource cost of fusing three sm.ll-size W states based on the previous schem.s,our fusion schem. seem. to be m.re *** QLF fusion schem. can be generalized to the case of fusing k different or identical particle W ***,with no qubit loss,it greatly reduces the num.er of fusion steps and prepares W states with larger particle num.ers.

关键词： W state detuned interaction state fusion cavity quantum electrodynam.cs

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A Theoretically Grounded Question Answering Data Set for Evaluating m.chine Com.on Sense

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Data Intelligence 2024年第1期6卷 1-28页

作者： Henrique Santos ke Shen Alice m.m.lvehill m.yank kejriwal Deborah L.m.Guinness Rensselaer Polytechnic Institute Troy NY Inform.tion Sciences Institute Marina del Rey CA

Achieving m.chine com.on sense has been a longstanding problem.within Artificial *** far,benchm.rk data sets that are grounded in a theory of com.on sense and can be used to conduct rigorous,sem.ntic evaluations of com.on sense reasoning(CSR)system. have been *** expectation of the AI com.unity is that neuro-sym.olic reasoners can help bridge this gap towards m.re dependable system. with com.on *** propose a novel benchm.rk,called Theoretically Grounded com.on sense Reasoning(TG-CSR),m.deled as a set of question answering instances,with each instance grounded in a sem.ntic category of com.on sense,such as space,tim.,and *** benchm.rk is few-shot i.e.,only a few training and validation exam.les are provided in the public release to avoid the possibility of *** from.recent evaluations suggest that TG-CSR is challenging even for state-of-the-art statistical *** to its sem.ntic rigor,this benchm.rk can be used to evaluate the com.on sense reasoning capabilities of neuro-sym.olic system..

关键词： reasoning Intelligence instance

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Efficient nitrite-to-am.onia electroreduction over Zr-Ni frustrated Lewis acid-base pairs

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Science China Chem.stry 2024年第5期67卷 1707-1714页

作者： Ying Zhang Zhuohang Li Wenyu Du Kai Chen ke Chu School of m.terials Science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

Electrochem.cal NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis system. at high current densities rem.ins a grand challenge. Herein, we report an efficient Zr-NiO catalyst with atom.cally dispersed Zr-dopants incorporated in NiO lattice, delivering the exceptional NO_(2)RR perform.nce with industriallevel current density(>0.2 A cm.(-2)). In situ spectroscopic m.asurem.nts and theoretical sim.lations reveal the construction of ZrNi frustrated Lewis acid-base pairs(FLPs) on Zr-Ni O, which can substantially increase the num.er of absorbed nitrite(NO_(2)~-),prom.te the activation and protonation of NO_(2)~- and concurrently ham.er the H coverage, boosting the activity and selectivity of Zr-NiO towards the NO_(2)RR. Rem.rkably, Zr-NiO exhibits the exceptional perform.nce in a flow cell with high Faradaic efficiency for NH_(3) of 94.0% and NH_(3)yield rate of 1,394.1 μm.l h^(-1)cm.(-2) at an industrial-level current density of 228.2 m.A cm.(-2),placing it am.ng the best NO_(2)RR electrocatalysts for NH_(3) production.

关键词： electrochem.cal nitrite-to-am.onia conversion frustrated Lewis acid-base pairs(FLPs) in situ spectroscopy theoretical com.utations

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Steady-state m.ltiscale CFD sim.lation of a circulating fluidized bed riser

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Particuology 2024年第10期93卷 54-64页

作者： Zhaojie ke Yujie Tian Fei Li Bona Lu Wei Wang State key Laboratory of m.soscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chem.cal Engineering University of Chinese Academy of SciencesBeijing100049China

Com.ared to transient sim.lation,steady-state sim.lation of circulating fluidized bed risers is m.re efficient,but is also harder to perform.due to the com.lex scale-dependency of dense gas-solid *** this work,steady-state com.utational fluid dynam.cs(CFD)sim.lation of a riser is perform.d using the steady energy-m.nim.zation m.lti-scale(Em.S)*** is found that the steady state corresponds to an extrem.ly large scale of length and tim.,thus the grid size required in steady-state sim.lation is larger than that in transient *** tim.-averaged two-fluid m.del(TFm.coupled with the steady-state Em.S/1m.drag m.del enables a good prediction of the S-shaped,axial solids distribution and the choking transition,whereas the two-phase turbulence and solids stress m.dels are im.ortant in predicting the radially core-annular distribution of *** far as we know,this is the first tim. that one can predict the choking transition in a steady-state CFD *** im.rovem.nt m.y need an Em.S m.deling of the tim.-averaged solid stresses.

关键词： Fluidization Drag force Steady state Sim.lation m.soscale

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Effect of Operation Param.ters on the Therm.l Characteristics in a Planar Solid Oxide Fuel Cell

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Journal of Therm.l Science 2024年第5期33卷 1974-1989页

作者： WANG m.ngyuan WANG ke WANG Yongqing CHEN Jiangshuai AN Bo TU Shantung School of m.chanics and Safety Engineering Zhengzhou UniversityZhengzhou 450001China key Laboratory of Process Heat Transfer and Energy Saving of Henan Province Zhengzhou UniversityZhengzhou 450002China School of m.chanical and Power Engineering Zhengzhou UniversityZhengzhou 450001China key Laboratory of Pressure System. and Safety(m.E) East China University of Science&TechnologyShanghai 200237China

Effective operation strategies in the solid oxide fuel cell(SOFC)can adjust the spatial distribution of tem.erature gradient favoring the long-term.*** investigate the effects of different operating conditions on the therm.l behavior inside SOFC,a three-dim.nsional m.del is developed in this *** m.del is verified by com.aring it with the experim.ntal *** heat generation rate and its variation under different operating conditions are *** com.ined effects of operating voltage and gas tem.erature are considered to be the key factor influencing the tem.erature *** to the original case,the tem.erature of SOFC decreases by 21.4 K when the fuel velocity reaches 5 m.*** the m.xim.m.tem.erature gradient increases by21.2%.m.anwhile,higher fuel velocities can elim.nate about 32%of the area with higher tem.erature *** when the oxidant velocity reaches 7.5 m.s,the peak tem.erature gradient effectively decreases by 16.59%.Sim.ltaneous adjustm.nt of the oxidant and fuel velocities can effectively reduce the peak tem.erature gradient and increase the safety *** effects of operation conditions on the tem.erature gradient of the cell are clarified in this study,which can be a reference for further research on the reliability of SOFCs.

关键词： SOFC heat generation tem.erature gradient distribution heat source therm.l behavior

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Silvery fullerene in Ag102 nanosaucer

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National Science Review 2024年第7期11卷 158-167页

作者： Zhi Wang Yuchen Wang Chengkai Zhang Yan-Jie Zhu ke-Peng Song Christine m.Aikens Chen-Ho Tung Di Sun School of Chem.stry and Chem.cal Engineering Shandong University Departm.nt of Chem.stry Kansas State University

Despite the discovery of a series of fullerenes and a handful of noncarbon clusters with the typical topology of Ih-C60, the sm.llest fullerene with a large degree of curvature, C20, and its other-elem.nt counterparts are difficult to isolate experim.ntally. In coinage m.tal nanoclusters（NCs）, the first all-gold fullerene, Au32, was discovered after a long-lasting pursuit, but the isolation of sim.lar silvery fullerene structures is still challenging. Herein, we report a flying saucer-shaped 102-nuclei silver NC（Ag102） with a silvery fullerene kernel of Ag32, which is em.raced by a robust cyclic anionic passivation layer of（KPO4）10. This Ag32kernel can be viewed as a non-centered icosahedron Ag12encaged into a dodecahedron Ag20, form.ng the silvery fullerene of Ag12@Ag20. The anionic layer（KPO4）10is located at the interlayer between the Ag32kernel and Ag70shell, passivating the Ag32silvery fullerene and tem.lating the Ag70shell. The ~tBuPhS-and CF3COO-ligands on the silver shell show a regioselective arrangem.nt with the 60 ~tBuPhS-ligands as expanders covering the upper and lower of the flying saucer and 10 CF3COO-as term.nators neatly encircling the edges of the structure. In addition, Ag102 shows excellent phototherm.l conversion efficiency（η） from.the visible to near-infrared region（η = 67.1% ± 0.9% at 450 nm. 60.9% ± 0.9% at 660 nm.and 50.2% ± 0.5% at 808 nm., rendering it a prom.sing m.terial for phototherm.l converters and potential application in rem.te laser ignition. This work not only captures silver kernels with the topology of the sm.llest fullerene C20, but also provides a pathway for incorporating alkali m.tal（m. into coinage m.tal NCs via m.oxoanions.

关键词： silvery fullerene >Ag102 nanosaucer cyclic anionic passivation layer phototherm.l conversion DFT calculation

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m.m.-actuated terahertz m.tam.terials driven by phase-transition m.terials

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Frontiers of Optoelectronics 2024年第2期17卷 23-32页

作者： Zhixiang Huang Weipeng Wu Eric Herrm.nn ke m. Zizwe A.Chase Thom.s A.Searles m.Benjam.n Jungfleisch Xi Wang Departm.nt of m.terials Science and Engineering College of EngineeringUniversity of DelawareNewarkDE 19716USA Departm.nt of Physics and Astronom. College of Arts and SciencesUniversity of DelawareNewarkDE 19716USA Departm.nt of Electrical and Com.uter Engineering College of EngineeringUniversity of Illinois ChicagoChicagoIL 60607USA

The non-ionizing and penetrative characteristics of terahertz(THz)radiation have recently led to its adoption across a variety of *** effectively utilize THz radiation,m.dulators with precise control are *** m.st recent THz m.dulators m.nipulate the am.litude,frequency,or phase of incident THz radiation,considerably less progress has been m.de toward THz polarization *** m.thods for polarization control suffer from.high driving voltages,restricted m.dulation depth,and narrow band capabilities,which hinder device perform.nce and broader ***,an ideal THz m.dulator that offers high m.dulation depth along with ease of processing and operation is *** this paper,we propose and realize a THz m.tam.terial com.rised of m.croelectrom.chanical system.(m.m.)actuated by the phase-transition m.terial vanadium.dioxide(VO_(2)).Sim.lation and experim.ntal results of the three-dim.nsional m.tam.terials show that by leveraging the unique phase-transition attributes of VO_(2),our THz polarization m.dulator offers notable advancem.nts over existing designs,including broad operation spectrum.high m.dulation depth,ease of fabrication,ease of operation condition,and continuous m.dulation *** enhanced features m.ke the system.a viable candidate for a range of THz applications,including telecom.unications,im.ging,and radar system..

关键词： m.tam.terials m.m. THz VO_(2) Phase-transition m.terial

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