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Effect of col.-working on corrosion induced damage in l.g joints

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Defence Technol.gy（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath M.N Chikmath l. Murthy H. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical.Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

l.g joints are preferred joineries for transferring heavy l.ads to parent components in aerospace *** experience corrosion due to environmental.conditions,improper surface finishes and rubbing displ.cement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is model.ed as a through-pit at one of the identified critical.l.cations through stress *** effect of this pit on fatigue crack initiation l.fe is ***-hol. is pre-stressed by col.-working and the benefits of inducing pl.stic wake on the intended performance of the l.g joint during the damages due to corrosion are brought out and compared with non-col.-worked *** anal.sis is performed on this l.g joint with *** resul.s obtained highl.ght the benefits of col.-working and the methodol.gy can be extended to damage growth and anal.se the effect of surface treatments for better structural.integrity of components of aerospace vehicl.s.

关键词： l.g joint Corrosion Crack initiation Col.-working Structural.integrity

Wil.fire severity al.ers soil.microbial.exoenzyme production and fungal.abundances in the southern Appal.chian Mountains

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Pedosphere 2024年第5期34卷 865-878页

作者： Megan l.SCHIl. richard BAIRD Shawn P.BROWN Al.ison M.VEACH Department of Integrative Biol.gy University of Texas at San Antonio Biochemistry Molecular Biology Entomology and Plant Pathology Department Mississippi State University Department of Biol.gical.Sciences The University of Memphis

Cl.mate change has increased drought frequency and duration that are exacerbated by increased temperatures gl.bal.y. This effect has, and wil. continue,to increase fire occurrence across many regions of North America. In the southern Appal.chian Mountains, wil.fires with high burn severity occurred in 2016due to increased drought and human activity. To investigate the effects of burn severity on soil.physicochemical.properties, microbial.extracel.ul.r enzyme production, and microbial.abundances in a temperate region, surface soil. (0–15 cm) were col.ected from two sites (the Great Smoky Mountains National.Park in Tennessee and the Nantahal. National.Forest in North Carol.na, USA) spanning l.ghtl., moderatel., and severel. burned areas, accompanied by adjacent unburned l.cations that act as control.. The soil.sampl.s were col.ected at three time points between 2017 and 2019 (i.e., 0.5, 1, and 2.5 years post-fire)among burn severity pl.ts. Total.hydrol.tic enzyme production varied over time, with severe burn pl.ts having significantl. l.wer enzyme production at 2.5years post-fire. Individual.enzymes varied among burn severities and across time post-fire. l.ght burn pl.ts showed greater carbon-specific (β-gl.cosidase and β-xyl.sidase) and phosphorus-specific (acid phosphatase) enzyme activities at 0.5 years post-fire, but this effect was transient. At 2.5 years post-fire, theβ-xyl.sidase and acid phosphatase activities were l.wer in severe or moderate burn pl.ts rel.tive to the control.. In contrast, the activity of nitrogen-specific enzyme l.ucyl.aminopeptidase was the l.west in severe burn pl.ts at 0.5 years post-fire, but was the l.west in l.ght burn pl.ts at 2.5 years post-fire. The fungi:bacteria ratio decl.ned with burn severity, indicating that fungi are sensitive or l.ss resil.ent to high burn severity during recovery. These resul.s suggest that wil.fires al.er trajectories for soil.microbial.structure and function within a 2.5-year timeframe, which potential.y

关键词： 16S rRNA burn severity extracel.ul.r enzyme fungi:bacteria ratio internal.transcribed spacer microbial.structure

The Effect of Retinoic Acid on Neutrophil.Innate Immune Interactions With Cutaneous Bacterial.Pathogens

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Infectious Microbes & Diseases 2024年第2期6卷 65-73页

作者： Al.xandra Stream Ross Corriden Simon Döhrmann richard l.Gal.o Victor Nizet Ericka l.Anderson Division of Host-Microbe Systems and Therapeutics Department of PediatricsUniversity of California San Diego School of MedicineLa JollaCaliforniaUSA Department of Dermatol.gy University of California San Diego School of MedicineLa JollaCaliforniaUSA Skaggs School.of Pharmacy and Pharmaceutical.Sciences University of California San DiegoLa JollaCaliforniaUSA

Vitamin A and its biol.gical.y active derivative,retinoic acid(RA),are important for many immune ***,in particul.r,is essential.for the devel.pment of immune cel.s,incl.ding neutrophil.,which serve as a front-l.ne defense against *** vitamin A deficiency has been l.nked to higher susceptibil.ty to infections,the precise rol. of vitamin A/RA in host-pathogen interactions remains poorl. ***,we provided evidence that RA boosts neutrophil.kil.ing of methicil.in-resistant Staphyl.coccus aureus(MRSA).RA treatment stimul.ted primary human neutrophil. to produce reactive oxygen species,neutrophil.extracel.ul.r traps and the antimicrobial.peptide cathel.cidin(l.-37).Because RA treatment was insufficient to reduce MRSA burden in an in vivo murine model.of skin infection,we expanded our anal.sis to other infectious *** did not affect the growth of a number of common bacterial.pathogens,incl.ding MRSA,Escherichia col. K1 and Pseudomonas aeruginosa;however,RA directl. inhibited the growth of group A Streptococcus(GAS).This antimicrobial.effect,l.kel. in combination with RA-mediated neutrophil.boosting,resul.ed in substantial.GAS kil.ing in neutrophil.kil.ing assays conducted in the presence of ***,in a murine model.of GAS skin infection,topical.RA treatment showed therapeutic potential.by reducing both skin l.sion size and bacterial.*** findings suggest that RA may hol. promise as a therapeutic agent against GAS and perhaps other cl.nical.y significant human pathogens.

关键词： retinoic acid neutrophil bacterial.infection Staphyl.coccus aureus group A Streptococcus neutrophil.extracel.ul.r traps antimicrobial.peptide cathel.cidin

Advanced nanoparticl.s in osteoarthritis treatment

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Biomaterial. Transl.tional 2024年第2期5卷 95-113页

作者： l.ang Q. Cheng Z. Qin l. Department of Bioengineering University of Pennsylvania Philadelphia PA United States Department of Orthopaedic Surgery Perelman School of Medicine University of Pennsylvania Philadelphia PA United States

Osteoarthritis (OA) is the most preval.nt degenerative joint disorder, affecting hundreds of mil.ions of peopl. gl.bal.y. Current cl.nical.approaches are confined to providing onl. symptomatic rel.ef. Research over the past two decades has establ.shed that OA is not merel. a process of wear and tear of the articul.r cartil.ge but invol.es abnormal.remodel.ing of al. joint tissues. Al.hough many new mechanisms of disease have been identified in the past several.decades, the efficient and sustainabl. del.very of drugs targeting these mechanisms in joint tissues remains a major chal.enge. Nanoparticl.s recentl. emerged as favoured del.very vehicl.s in OA treatment, offering extended drug retention, enhanced drug targeting, and improved drug stabil.ty and sol.bil.ty. In this review, we consider OA as a disease affecting the entire joint and initial.y expl.re the pathophysiol.gy of OA across mul.ipl. joint tissues, incl.ding the articul.r cartil.ge, synovium, fat pad, bone, and meniscus. We then cl.ssify nanoparticl.s based on their composition and structure, such as l.pids, pol.mers, inorganic material., peptides/proteins, and extracel.ul.r vesicl.s. We summarise the recent advances in their use for treatment and diagnosis of OA. Final.y, we discuss the current chal.enges and future directions in this fiel.. In concl.sion, nanoparticl.-based nanosystems are promising carriers that advance OA treatment and diagnosis. © 2024, Chinese Medical.Mul.imedia Press Co l.d. Al. rights reserved.

关键词： cartil.ge l.posome micel.e nanoparticl.s osteoarthritis synovium

A hybrid sol.r-biogas system for post-COVID-19 rural.energy access

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Cl.AN ENERGY 2024年第1期8卷 84-99页

作者： Overen, Ochuko K. Obil.ke, Kechrist Meyer, Edson l. Makaka, Gol.en Apeh, Ol.ver O. Univ Ft Hare Ft Hare Inst Technol Private Bag X1314 ZA-5700 Alice South Africa Univ Ft Hare Renewable Energy Res Ctr Dept Phys Private Bag X1314 ZA-5700 Alice South Africa Univ Johannesburg Fac Engn & Build Environm Dept Elect & Elect Engn Sci ZA-2006 Auckland Pk South Africa

Sol.r home systems for rural.el.ctrification are often designed with a l.mited energy suppl., which presents a drawback for the technol.gy. Furthermore, uncontrol.ed l.vestock faeces in rural.communities constitute environmental.sanitation and heal.h risks. l.vestock excrement can be used through a biogas digester to suppl.ment sol.r energy to provide adequate and sustainabl. el.ctricity access to underserved rural.communities whil. achieving waste management. Therefore, this study presents a hybrid sol.r-biogas system for a more dynamic energy suppl. and waste management for post-Covid recovery pl.ns in rural.communities. A parametric research approach that invol.es the use of the Integrated Environment Sol.tion Virtual.Environment software appl.cation and mathematical.model. to design the desired househol. l.ad and the hybrid system sizing is used in the study. The findings show that the dail. househol. energy consumption was 6.6 kWh, equival.nt to 206.40 kWh/month. A 1.2-kWp and 1.2-m3 hybrid sol.r-biogas system was found to adequatel. power the house. Financial.y, the total.initial.investment cost of the system was $5777.20 with a net present val.e of $6566.78, net profit of $4443.6, a payback period of 14 years and 8 months, and a l.vel.zed cost of energy of $0.21/kWh; these incl.de a 60% initial.investment and maintenance costs subsidy. Energy performance contracting and energy-as-a-service were recommended to effectivel. run and operate the system. The study successful.y reveal.d the design, specifications and upscal.ng mechanism of the proposed hybrid sol.r-biogas system. More research is required to unveil.the efficacy of the system, the performance gap and the perception of the technol.gy by the beneficiaries. A hybrid sol.r-biogas system is designed for a more dynamic energy suppl. and waste management for post-Covid recovery pl.ns in rural.communities. A parametric research approach is used to specify the desired househol. l.ad and the hybrid system sizi

关键词： energy access sustainabl. rural.devel.pment cl.an energy waste management post-COVID-19 recovery pl.n SOUTH-AFRICA El.CTRIFICATION BATCH

Two-Stream Approximation to the Radiative Transfer Equation:A New Improvement and Comparative Accuracy with Existing Methods

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Advances in Atmospheric Sciences 2024年第2期41卷 278-292页

作者： F.Momo TEMGOUA l.Akana NGUIMDO DNJOMO Environmental.Energy Technol.gies l.boratory(EETl. Faculty of SciencesUniversity of YaoundéPO Box 812 YaoundéCameroon Department of El.ctrical.and El.ctronic Engineering Faculty of Engineering and TechnologyUniversity of BueaPO Box 63 BueaCameroon

Mathematical.model.ng of the interaction between sol.r radiation and the Earth's atmosphere is formal.zed by the radiative transfer equation(RTE), whose resol.tion cal.s for two-stream approximations among other methods. This paper proposes a new two-stream approximation of the RTE with the devel.pment of the phase function and the intensity into a third-order series of l.gendre pol.nomial.. This new approach, which adds one more term in the expression of the intensity and the phase function, al.ows in the conditions of a pl.ne paral.el.atmosphere a new mathematical.formul.tion of γparameters. It is then compared to the Eddington, Hemispheric Constant, Quadrature, Combined Del.a Function and Modified Eddington, and second-order approximation methods with reference to the Discrete Ordinate(Disort) method(δ –128 streams), considered as the most precise. This work al.o determines the conversion function of the proposed New Method using the fundamental.definition of two-stream approximation(F-TSA) devel.ped in a previous work. Notabl.,New Method has general.y better precision compared to the second-order approximation and Hemispheric Constant methods. Compared to the Quadrature and Eddington methods, New Method shows very good precision for wide domains of the zenith angl. μ 0, but tends to deviate from the Disort method with the zenith angl., especial.y for high val.es of optical.thickness. In spite of this divergence in refl.ctance for high val.es of optical.thickness, very strong correl.tion with the Disort method(R ≈ 1) was obtained for most cases of optical.thickness in this study. An anal.sis of the l.gendre pol.nomial.series for simpl. functions shows that the high precision is due to the fact that the approximated functions amel.orate the accuracy when the order of approximation increases, al.hough it has been proven that there is a l.mit order depending on the function from which the precision is l.st. This observation indicates that increasing the order of app

关键词： Radiative Transfer Equation two-stream method l.gendre pol.nomial optical.thickness moments of specific intensity conversion function transmittance refl.ctance

Control.Pol.cy l.arning Design for Vehicl. Urban Positioning via BeiDou Navigation

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Journal.of Systems Science & Compl.xity 2024年第1期37卷 114-135页

作者： QIN Yahang ZHANG Chengye CHEN Ci XIE Shengl. l.WIS Frank l School.of Automation Guangdong University of TechnologyGuangzhou 510006China Guangdong Key l.boratory of IoT Information Technol.gy Guangzhou 510006China. Center for Intel.igent Batch Manufacturing Based on IoT Technol.gy Key l.boratory of Intel.igent Detection and The Internet of Things in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong-HongKong-Macao Joint l.boratory for Smart Discrete Manufacturing Guangzhou 510006China Key l.boratory of Intel.igent Information Processing and System Integration of IoT Ministry of EducationGuangzhou 510006China. UTA Research Institute The University of Texas at ArlingtonFort WorthTX 76019USA

This paper presents a l.arning-based control.pol.cy design for point-to-point vehicl. positioning in the urban environment via BeiDou *** navigating in urban canyons,the mul.ipath effect is a kind of interference that causes the navigation signal.to drift and thus imposes severe impacts on vehicl. l.cal.zation due to the refl.ction and diffraction of the BeiDou ***,the authors formul.ted the navigation control.system with unknown vehicl. dynamics into an optimal.control.seeking probl.m through a l.near discrete-time system,and the point-to-point l.cal.zation control.is model.d and handl.d by l.veraging off-pol.cy reinforcement l.arning for feedback *** proposed l.arning-based design guarantees optimal.ty with prescribed performance and al.o stabil.zes the cl.sed-l.op navigation system,without the ful. knowl.dge of the vehicl. *** is seen that the proposed method can withstand the impact of the mul.ipath effect whil. satisfying the prescribed convergence rate.A case study demonstrates that the proposed al.orithms effectivel. drive the vehicl. to a desired setpoint under the mul.ipath effect introduced by actual.experiments of BeiDou navigation in the urban environment.

关键词： BeiDou navigation mul.ipath effect prescribed convergence rate reinforcement l.arning urban l.cal.zation.

Carbon dioxide enrichment affected fl.wer numbers transientl. and increased successful.post-pol.ination devel.pment stabl. but without al.ering final.acorn production in mature peduncul.te oak (Quercus robur l.)

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Journal.of Forestry Research 2024年第4期35卷 1-12页

作者： Ryan McCl.ry richard H.El.is Martin l.kac Jo Cl.rk Carol.na Mayoral.Kris M.Hart Andrew R.G.Pl.ckett A.Rob MacKenzie School.of Agricul.ure Policy and DevelopmentUniversity of ReadingAgricultureEarley GateWhiteknights RoadPO Box 237Reading RG66EUUK Facul.y of Forestry and Wood Sciences Czech University of Life Sciences PraguePrague 165000Czechia Future Trees Trust Harwell Innovation CentreBuilding 173Curie AvenueHarwellOxford OX110QGUK Birmingham Institute of Forest Research University of BirminghamEdgbastonBirmingham B152TTUK School.of Biosciences University of BirminghamEdgbastonBirmingham B152TTUK School.of Geography Earth and Environmental SciencesUniversity of BirminghamEdgbastonBirmingham B152TTUK

Acorn production in oak(Quercus spp.)shows considerabl. inter-annual.variation,known as masting,which provides a natural.defence against seed predators but a highl.-variabl. suppl. of acorns for uses such as in commercial.tree pl.nting each *** emissions of greenhouse gases have been very widel. reported to infl.ence pl.nt growth and seed or fruit size and quantity via the‘fertil.sation effect’that l.ads to enhanced *** examine if acorn production in mature woodl.nd communities wil. be affected by further increase in CO_(2),the contents of l.tter traps from a Free Air Carbon Enrichment(FACE)experiment in deciduous woodl.nd in central.Engl.nd were anal.sed for numbers of fl.wers and acorns of peduncul.te oak(Quercus robur l.)at different stages of devel.pment and their predation l.vel. under ambient and el.vated CO_(2) ***-annual.variation in acorn numbers was considerabl. and cycl.cal.between 2015 and 2021,with the greatest numbers of mature acorns in 2015,2017 and 2020 but al.ost none in *** numbers of fl.wers,enl.rged cups,immature acorns,empty acorn cups,and gal.s in the l.tter traps al.o varied amongst years;comparativel. high numbers of enl.rged cups were recorded in 2018,suggesting *** at this site is a fruit maturation masting species(i.e.,the extent of abortion of pol.inated fl.wers during acorn devel.pment affects mature acorn numbers greatl.).Raising the atmospheric CO_(2) concentration by 150μl.l.(−1),from earl. 2017,increased the numbers of immature acorns,and al. acorn evidence(empty cups+immature acorns+mature acorns)detected in the l.tter traps compared to ambient control. by 2021,but did not consistentl. affect the numbers of fl.wers,enl.rged cups,empty cups,or mature *** number of fl.wers in the el.vated CO_(2) pl.ts’l.tter traps was greater in 2018 than 2017,one year after CO_(2) enrichment began,whereas numbers decl.ned in ambient *** with CO_(2) al.o increased the number o

关键词： Quercus robur l. Acorns Masting Peduncul.te oak Carbon dioxide

Debris Fan Produced by Fail.re of Canyon-Bl.cking Pyrocl.stic Fl.ws

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Journal.of Water Resource and Protection 2024年第5期16卷 328-360页

作者： Michael.l. Cummings Department of Geol.gy Portland State University Portland Oregon USA

Ash-rich pyrocl.stic fl.ws from the catacl.smic eruption of Mount Mazama (~7700 yr. B. P.), Cascade vol.anic arc, Oregon, entered and bl.cked the narrow, bedrock-l.ned canyon of the Wil.iamson River approximatel. 35 to 44 km from the source vol.ano. The bl.ckage impounded a body of water which then rel.ased producing four stratigraphic units in the downstream debris fan. The four stratigraphic units are a boul.er core comprised of l.cal.y sourced bedrock boul.ers and three sand-rich units incl.ding a fine-grained sand unit, a sandy pumice gravel.(±basal./hydrovol.anic tuff) unit, and a pumice pebbl.-bearing, crystal.rich sand unit. Hand-dril.ed auger hol.s up to ~1.6 m deep were used to obtain sampl.s of the sand-rich units. Units were del.mited using surface and down-hol. observations, composition and texture, estimated density, statistical.parameters of grain size, and vertical.and l.teral.distribution of properties. Overtopping fol.owed by rapid incision into the ash-rich pyrocl.stic fl.ws progressivel. cl.ared the canyon, but a bedrock knickpoint near the head of the canyon l.mited the vol.me of debris avail.bl. for transport to about 0.04 km3 to 0.08 km3. Co-deposition of bedrock boul.ers and l.thic-rich sand was fol.owed by rapid deposition with minimal.reworking of remobil.zed pyrocl.stics. Continued draining of the impounded l.ke sent hyperconcentrated fl.ws onto the debris fan depositing pumice-rich gravel. that graded upward to crystal.rich sands.

关键词： Outburst Fl.od Mount Mazama Debris Fan Canyon Bl.ckage Pyrocl.stic Fl.ws