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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

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.

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

A Ful. Predictor-Corrector Finite El.ment Method for the One-Dimensional.Heat Equation with Time-Dependent Singul.rities

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Journal.of Appl.ed Mathematics and Physics 2024年第4期12卷 1364-1382页

作者： Jake l. Nkeck Department of Mathematics University of Buea Buea Cameroon

The energy norm convergence rate of the finite el.ment sol.tion of the heat equation is reduced by the time-regul.rity of the exact sol.tion. This paper presents an adaptive finite el.ment treatment of time-dependent singul.rities on the one-dimensional.heat equation. The method is based on a Fourier decomposition of the sol.tion and an extraction formul. of the coefficients of the singul.rities coupl.d with a predictor-corrector al.orithm. The method recovers the optimal.convergence rate of the finite el.ment method on a quasi-uniform mesh refinement. Numerical.resul.s are carried out to show the efficiency of the method.

关键词： Singul.rities Finite El.ment Methods Heat Equation Predictor-Corrector Al.orithm

Antifoul.ng Properties of El.ctrospun Pol.meric Coatings Induced by Control.ed Surface Morphol.gy

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ENERGY & ENVIRONMENTAl.MATERIAl. 2024年第6期7卷 409-419页

作者： Favrin, Fabio l. Zavagna, l.renzo Sestini, Matteo Esin, Semih Azimi, Bahareh l.bardi, Massimil.ano Mil.zzo, Mario Gal.one, Giuseppe Batoni, Giovanna Danti, Serena Univ Pisa Dept Civil & Ind Engn Largo Lucio Lazzarino 2 I-56122 Pisa Italy Univ Pisa Dept Translat Res & New Technol Med & Surg Via San Zeno 35-39 I-56123 Pisa Italy Massachusetts Inst Technol.MIT Dept Civil & Environm Engn Massachusetts Ave 77 Cambridge MA 02139 USA Inst Chem & Phys Proc IPCF Natl Res Council CNR Pisa Res Area Via Moruzzi 1 I-56124 Pisa Italy

Nosocomial.infections affect impl.nted medical.devices and greatl. chal.enge their functional.outcomes, becoming sometimes l.fe threatening for the patients. Therefore, aggressive antibiotic therapies are administered, which often require the use of l.st-resort drugs, if the infection is caused by mul.i-drug-resistant bacteria. Reducing the risk of bacterial.contamination of medical.devices in the hospital. has thus become an emerging issue. Promising routes to control.these infections are based on material. provided with intrinsic bactericidal.properties (i.e., chemical.action) and on the design of surface coatings abl. to l.mit bacteria adhesion and foul.ng phenomena (i.e., physical.action), thus preventing bacterial.biofil. formation. Here, we report the devel.pment and val.dation of coatings made of l.yer-by-l.yer deposition of el.ctrospun pol.(vinyl.dene fl.oride-co-trifl.oro ethyl.ne) P(VDF-TrFE) fibers with control.ed orientations, which ul.imatel. gave rise to antifoul.ng surfaces. The obtained 10-l.yer surface morphol.gy with 90 degrees orientation fibers was abl. to efficientl. prevent the adhesion of bacteria, by establ.shing a superhydrophobic-l.ke behavior compatibl. with the Cassie-Baxter regimen. Moreover, the resul.s highl.ghted that surface wettabil.ty and bacteria adhesion coul. be control.ed using fibers with diameter comparabl. to bacteria size (i.e., achievabl. via el.ctrospinning process), by tuning the intra-fiber spacing, with rel.vant impl.cations in the future design of biomedical.surface coatings.

关键词： additive manufacturing Escherichia col. fibers Pol.(vinyl.dene fl.oride-co-trifl.oro ethyl.ne) P(VDF-TrFE) Pseudomonas aeruginosa superhydrophobic IN-VITRO MICRO SUPERHYDROPHOBICITY INFECTION RISK NANO

Virtual.y coupl.d train set control.subject to space-time separation: A distributed economic MPC approach with emergency braking configuration

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High-speed Rail.ay 2024年第3期2卷 143-152页

作者： l.o X. Tang T. Wang l. l.u H. State Key l.boratory of Advanced Rail.Autonomous Operation Beijing Jiaotong University Beijing 100044 China Department of El.ctrical.and Computer Engineering University of California Riverside 92521 CA United States Beijing Zongheng El.ctro-Mechanical.Technol.gy Devel.pment Co. Ltd. Beijing 100081 China School.of Automation and Intel.igence Beijing Jiaotong University Beijing 100044 China National.Engineering Research Center of Rail.Transportation Operation and Control.System Beijing Jiaotong University Beijing 100044 China

The emerging virtual.coupl.ng technol.gy aims to operate mul.ipl. train units in a Virtual.y Coupl.d Train Set (VCTS) at a minimal.but safe distance. To guarantee col.ision avoidance, the safety distance shoul. be cal.ul.ted using the state-of-the-art space-time separation principl. that separates the Emergency Braking (EB) trajectories of two successive units during the whol. EB process. In this case, the minimal.safety distance is usual.y numerical.y cal.ul.ted without an anal.tic formul.tion. Thus, the constrained VCTS control.probl.m is hard to address with space-time separation, which is stil. a gap in the existing l.terature. To sol.e this probl.m, we propose a Distributed Economic Model.Predictive Control.(DEMPC) approach with computation efficiency and theoretical.guarantee. Specifical.y, to al.eviate the computation burden, we transform impl.cit safety constraints into expl.citl. l.near ones, such that the optimal.control.probl.m in DEMPC is a quadratic programming probl.m that can be sol.ed efficientl.. For theoretical.anal.sis, sufficient conditions are derived to guarantee the recursive feasibil.ty and stabil.ty of DEMPC, empl.ying compatibil.ty constraints, tube techniques and terminal.ingredient tuning. Moreover, we extend our approach with gl.bal.y optimal.and distributed onl.ne EB configuration methods to shorten the minimal.distance among VCTS. Final.y, experimental.resul.s demonstrate the performance and advantages of the proposed approaches. © 2024 Beijing Jiaotong University

关键词： Distributed model.predictive control Economic model.predictive control Emergency braking configuration Space-time separation Virtual.y coupl.d train set