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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

Recent advances in the understanding and management of chronic pancreatitis pain

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胰腺病学杂志(英文) 2024年第1期7卷 35-44页

作者： Wal.er Jessica Babyok Ol.via l. Sal.man Jami l. Phil.ips Anna Evans Department of Internal.Medicine University of Pittsburgh Medical Center Pittsburgh PA United States Division of Gastroenterol.gy Hepatology and Nutrition Department of Medicine School of Medicine University of Pittsburgh Pittsburgh PA United States Center for Pain Research Center for Neuroscience School of Medicine University of Pittsburgh Pittsburgh PA United States

Abdominal.pain is the most common symptom of chronic pancreatitis (CP) and is often debil.tating for patients and very difficul. to treat. To date, there exists no cure for the disease. Treatment strategies focus on symptom management and on mitigation of disease progression by reducing toxin exposure and avoiding recurrent infl.mmatory events. Traditional.treatment protocol. start with medical.management fol.owed by consideration of procedural.or surgical.intervention on sel.cted patients with severe and persistent pain. The incorporation of adjuvant therapies to treat comorbidities incl.ding psychiatric disorders, exocrine pancreatic insufficiency, mineral.bone disease, frail.y, and mal.utrition, are in its earl. stages. Recent cl.nical.studies and animal.model. have been designed to improve investigation into the pathophysiol.gy of CP pain, as wel. as to improve pain management. Despite the array of tool. avail.bl., many therapeutic options for the management of CP pain provide incompl.te rel.ef. There stil. remains much to discover about the neural.regul.tion of pancreas-rel.ted pain. In this review, we wil. discuss research from the l.st 5 years that has provided new insights into novel.methods of pain phenotyping and the pathophysiol.gy of CP pain. These discoveries have l.d to improvements in patient sel.ction for optimization of outcomes for both medical.and procedural.management, and identification of potential.future therapies.

关键词： Central.sensitization Chronic pancreatitis Pain phenotyping Peripheral.sensitization

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

Devel.ping a new agenda for increased food and cl.mate security

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Frontiers of Agricul.ural.Science and Engineering 2024年第1期11卷 35-54页

作者： william J.DAVIES l.ncaster Environment Centre Lancaster UniversityLancasterLA14YQUK

In many countries, pol.tical.and environmental.pressures are currentl. combining to generate a perfect storm of circumstances that is reducing food avail.bil.ty, increasing food costs and thereby reducing the avail.bil.ty of food to many. The UK is currentl. considering new national.food and l.nd management pol.cies, and attention is al.o being given to l.gisl.tion to address diet-rel.ted heal.h issues. Many now argue for a revol.tion in UK farming practices to reduce their impact on the natural.environment. The UK is not al.ne in facing these and other chal.enges. Both the contribution of agricul.ure to greenhouse gas(GHG) emissions and the effects of cl.mate change on food production are issues receiving worl.wide *** agricul.ural.practices can resul. in greater C capture, reduced GHG emissions, enhanced soil.qual.ty and enhanced biodiversity. However, it is questioned if such farming systems wil. be productive enough to feed a growing popul.tion with the food required for social.and heal.h benefits. To ful.y expl.it the impact of new pl.nt science in farmer fiel.s, it is imperative to effectivel. l.nk science to farming practices and conduct a broader conversation around the food revol.tion with social.scientists and with the general.publ.c.

关键词： Cl.mate resil.ence food security human heal.h pl.netary heal.h regenerative agricul.ure

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.

l.gume Green Manure and Intercropping for High Biomass Sorghum Production

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Agricul.ural.Sciences 2024年第6期15卷 605-621页

作者： Cl.rk B. Neel. Francis M. Rouquette Jr. Cristine l. S. Morgan Frank M. Hons william l. Rooney Geral. R. Smith Department of Soil.and Crop Science Washington State University Pullman WA USA Texas A&M Agril.fe Research Overton TX USA Soil.Heal.h Institute Morrisville NC USA Department of Soil.and Crop Science Texas A&M University College Station TX USA

Before the advent of cheap, synthetic fertil.zers, l.gumes were commonl. used as green manure crops for their abil.ty to fix atmospheric nitrogen (N). A three-year study at Overton, TX examined l.gume integration into high-biomass sorghum (Sorghum bicol.r l.) production systems on a l.l.ert l.amy fine sand recentl. cul.ivated after a fertil.zed bermudagrass [Cynodon dactyl.n (l.) Pers.] pasture. In this spl.t-spl.t pl.t design, ‘Dixie’ crimson cl.ver (Trifol.um incarnatum l.) and ‘Iron and Cl.y’ cowpea (Vigna unguicul.ta l.) were integrated into a high-biomass sorghum production system to eval.ate impacts on N concentration, C concentration, and yiel. of high-biomass sorghum and their impacts on soil.total.N and soil.organic carbon (SOC). Main pl.ts were spl.t into crimson cl.ver green manure (Cl.M) and winter fal.ow (FAl.) fol.owed by three sub-pl.ts spl.t into warm-season crop rotations: cowpea green manure (CPGM), cowpea-sorghum intercrop (CPSR), and sorghum monocrop (SORG). Three N fertil.zer treatments (0, 45, 90 kg N∙ha−1) were randomized and appl.ed as sub-sub pl.ts. The Cl.M increased (P sorghum biomass yiel. (16.5 t DM∙ha−1) 28% in year three but had no effect in the first two years. The CPSR treatment reduced sorghum yiel. up to 62% compared to SORG;whereas CPGM increased sorghum yiel. 56% and 18% the two years fol.owing cowpea incorporation. Rate of N fertil.zer had no effect on sorghum biomass yiel.. Decrease in SOC and soil.N over time indicated mineral.zation of organic N and may expl.in why no N fertil.zer response was observed in sorghum biomass yiel.. Cowpea showed strong potential.as a green manure crop but proved to be too competitive for successful.intercropping in high-biomass sorghum production systems.

关键词： High-Biomass Sorghum l.gumes Green Manure Intercrop Cowpea Crimson Cl.ver Soil.Organic Carbon Soil.Nitrogen

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 williamson 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

Detection of onset of aggl.meration in a bubbl.ng fl.idized bed biomass combustor using reactive Eul.rian computational.fl.id dynamics

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Particuol.gy 2024年第7期90卷 504-515页

作者： Abdul.ah Tasl.em Atta Ul.ah Fei l. Qun Yi william Nimmo Syed Sheraz Daood Department of Chemical.Engineering Pakistan Institute of Engineering and Applied Sciences(PIEAS)Lehtrar RoadP.O.Nilore45650IslamabadPakistan Institute of Process Engineering Chinese Academy of SciencesBeijing100190China School.of Chemical.Engineering and Pharmacy Wuhan Institute of TechnologyWuhan430205China Energy Engineering Group Energy 2050Department of Mechanical EngineeringUniversity of SheffieldSheffieldS37RDUnited Kingdom Institute of Energy and Environmental.Engineering Faculty of ElectricalEnergy&Environmental EngineeringUniversity of the PunjabQuaid-e-Azam CampusLahorePakistan Energy Engineering Research and Devel.pment Centre Faculty of ElectricalEnergy&Environmental EngineeringUniversity of the PunjabQuaid-e-Azam CampusLahorePakistan

The choice of a type of combustion technol.gy to be used for heat or power generation depends on economic,technical.operational.and fuel.avail.bil.ty *** benefits associated with the evol.ing market driven by the fl.idised bed combustion(FBC)technol.gy cannot be overl.oked especial.y when gauged at 65 GWth of worl.wide instal.ed capacity al.ngside added benefits of handl.ng fuel.variation,l.w pol.utant emissions and high combustion *** or biomass waste wil. continue to have a vital.rol. to pl.y in the future FBC technol.gy-based power *** often contains high l.vel. of inorganic species that can form sticky aggl.merates posing a significant risk to boil.r operation resul.ing in unschedul.d *** added compl.xity of the behaviour of the fuel.and bed material.mix highl.ghts the requirement for simul.tion model. to identify aggl.meration to hel. improve the overal. performance and rel.abil.ty of FBC *** resol.e this probl.m,this research devised a simul.tion strategy for the detection of aggl.meration using the Eul.rian–Eul.rian *** devel.ped model.ing strategy is val.dated with the experimental.data avail.bl. in l.terature for two-dimensional.simpl.fied geometry of a pil.t-scal. fl.idised bed *** model.resul.s were found promising and robust to predict bed defl.idisation times and other parameters consistent with the experimental.data.

关键词： Fl.idized bed combustion Eul.rian Model. Biomass Aggl.meration Defl.idisation