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Journal of Magnesium and Alloys 2019年第1期7卷 47-57页

作者： samuel leleu Bertrand Rives Nicolas Causse Nadine Pébère CIRIMAT Universitéde ToulouseCNRSINPTUPSENSIACET4 allée Emile Monso BP4436231030 Toulouse cedex 4 France IRT Saint Exupéry 118 route de Narbonne-CS 4424831432 ToulouseFrance

The corrosion resistance of three Mg alloys containing rare-earth elements(WE43,EV31 and ZE41)was studied and compared to that of two Mg-Al alloys(AZ31 and AZ91)and of pure Mg(99.95 wt.%).Current-voltage curves and electrochemical impedance measurements were performed with rotating disk electrodes in an aerated 0.1 M Na_(2)SO_(4)*** all the alloys,it was confirmed that the intermetallic particles acted as local cathodes and that more protective films were formed on the alloys surface by comparison with the pure *** rates were determined from inductive coupled plasma-optical emission spectroscopy measurements and from the electrochemical *** corrosion rates were observed for the rare-earth Mg alloys compared to the AZ series *** data allowed the corrosion mechanisms to be discussed.

关键词： Magnesium alloys Rare-earth elements EIS ICP-OES Interface

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Neural Regeneration Research 2025年第2期20卷 366-377页

作者： samuel Abokyi Dennis Yan-yin Tse School of Optometry The Hong Kong Polytechnic UniversityKowloonHong Kong Special Administrative RegionChina Research Center for SHARP Vision The Hong Kong Polytechnic UniversityKowloonHong Kong Special Administrative RegionChina Center for Eye and Vision Research Sha TinHong Kong Special Administrative RegionChina

Retinal aging has been recognized as a significant risk factor for various retinal disorders,including diabetic retinopathy,age-related macular degeneration,and glaucoma,following a growing understanding of the molecular underpinnings of their *** comprehensive review explores the mechanisms of retinal aging and investigates potential neuroprotective approaches,focusing on the activation of transcription factor *** meta-analyses have demonstrated promising outcomes of transcription factor EB-targeted strategies,such as exercise,calorie restriction,rapamycin,and metformin,in patients and animal models of these common retinal *** review critically assesses the role of transcription factor EB in retinal biology during aging,its neuroprotective effects,and its therapeutic potential for retinal *** impact of transcription factor EB on retinal aging is cell-specific,influencing metabolic reprogramming and energy homeostasis in retinal neurons through the regulation of mitochondrial quality control and nutrient-sensing *** vascular endothelial cells,transcription factor EB controls important processes,including endothelial cell proliferation,endothelial tube formation,and nitric oxide levels,thereby influencing the inner blood-retinal barrier,angiogenesis,and retinal ***,transcription factor EB affects vascular smooth muscle cells,inhibiting vascular calcification and *** retinal pigment epithelial cells,transcription factor EB modulates functions such as autophagy,lysosomal dynamics,and clearance of the aging pigment lipofuscin,thereby promoting photoreceptor survival and regulating vascular endothelial growth factor A expression involved in *** cell-specific functions of transcription factor EB significantly impact retinal aging mechanisms encompassing proteostasis,neuronal synapse plasticity,energy metabolism,microvasculature,and inflammation,ultimately offering pro

关键词： age-related macular degeneration anti-aging interventions autophagy calorie restriction diabetic retinopathy exercise glaucoma neuromodulation phagocytosis photoreceptor outer segment degradation retinal aging transcription factor EB

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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Neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer M.Colón-Mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose M.Santiago samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis H.Pagan Rivera Jorge D.Miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA National Institutes of Health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of Neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

Sulfurized-polyacrylonitrile in lithium-sulfur batteries:Interactions between undercoordinated carbons and polymer structure under low lithiation

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Journal of Energy Chemistry 2022年第3期31卷 587-596,I0016页

作者： samuel Bertolini Timo Jacob Institute of Electrochemistry Ulm UniversityAlbert-Einstein-Allee 4789081 UlmGermany Helmholtz-Institute Ulm(HIU) Electrochemical Energy StorageHelmholtzstr.1189081 UlmGermany Karlsruhe Institute of Technology(KIT) P.O.Box 364076021 KarlsruheGermany

Lithium-sulfur battery(LSB)represents an important candidate to be used in energy storage applications,due to its high specific ***-polyacrylonitrile(SPAN)is a candidate as a host material in LSB to replace graphite,due to its ability to chemisorb polysulfides(PSs).The sulfur chains attached to the polymer can reversibly form Li2S,and SPAN indicates to have a good cyclability and better performance than graphite,thus,SPAN acts partially as an active and also as a host *** this study,we investigated the capacity of the solvent or the SPAN to lose a hydrogen atom from the backbone,to predict possible anodic reactions between solvent and host *** simulation suggests that the photophilic salts may preferentially react with the solvent,and possibly building a cathode electrolyte interphase(CEI).We observed that an undercoordinated carbon(C_(uc))can be thermodynamically created,due to *** Cuccan react with the solvent on the polymer backbone through different mechanisms,however,the simulations indicated that the reaction should be affected by the interaction between the solvent and C_(uc),according to SPAN’s ***,C_(uc)reacts with long sulfur chains attached to SPAN,capturing sulfur and forming a C-S bond.A sulfur chain from one SPAN can connect to another polymer backbone,however,this process is affected by lithiation and ***,this work also investigates the formation of interconnected SPAN structures and the multiple C_(uc)effects.

关键词： Density functional theory Ab initio molecular dynamics Lithium-sulfur batteries Sulfurized-polyacrylonitrile

Flow, thermal criticality and transition of a reactive third-grade fluid in a pipe with Reynolds' model viscosity

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Journal of Hydrodynamics 2016年第1期28卷 84-94页

作者： samuel S.OKOYA Department of Mathematics Obafemi Awolowo University

Neglecting the consumption of the material, a steady incompressible flow of an exothermic reacting third-grade fluid with viscous heating in a circular cylindrical pipe is numerically studied for both cases of constant viscosity and Reynolds＇ viscosity model. The coupled ordinary differential equations governing the flow in cylindrical coordinates, are transformed into dimensionless forms using appropriate transformations, and then solved numerically. Solutions using Maple are presented in tabular form and given in terms of dimensionless central fluid velocity and temperature, skin friction and heat transfer rate for three parametric values in the Reynolds＇ case. The numerical results for the velocity and temperature fields are also presented through graphs. Bifurcations are discussed using shooting method. Comparisons are also made between the present results and those of previous work, and thus verify the validity of the provided numerical solutions. Important properties of thermal criticality are provided for variable viscosity parameter and reaction order. Further numerical results are presented in the form of tables and graphs for transition of physical parameters, while varying certain flow and fluid material parameters. Also, the flow behaviour of the reactive fluid of third-grade is compared with those of the Newtonian reactive fluid.

关键词： non-Newtonian fluids third-grade fluid thermal transition heat generation temperature dependent viscosity numerical solutions

Research trend of cascade heat pumps

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Science China(Technological Sciences) 2017年第11期60卷 1597-1615页

作者： BOAHEN samuel CHOI JongMin Graduate School of Mechanical Engineering Hanbat National UniversityDaejeon 34158Korea Department of Mechanical Engineering Hanbat National UniversityDaejeon 34158Korea

Most commercial and industrial facilities require very low temperatures for refrigeration and high temperatures for space heating and hot water purposes. Single stage heat pumps have not been able to meet these temperature demands and have been characterized by low capacities and coefficient of performance(COP). Cascade heat pump has been developed to overcome the weaknesses of single stage heat pumps. This study reviews recent works done by researchers on cascade heat pumps for refrigeration, heating and hot water generation. Selection of suitable refrigerants to meet the pressure and temperature demands of each stage of the cascade heat pump has been discussed. Optimization of design parameters such as intermediate temperature(low stage condensing and high stage evaporating temperatures), and temperature difference in the cascade heat exchanger for optimum performance of the cascade heat pump has been reviewed. It was found that optimising each design parameter of the cascade heat pump is necessary for maximum system performance and this may improve the exergetic efficiency, especially of cascade refrigeration systems, by about 30.88%. Cascade heat pumps have wider range of application especially for artificial snow production, in the supermarkets,for natural gas liquefaction, in drying clothes and food and as heat recovery system. The performance of cascade heat pumps can be improved by 19% when coupled with other renewable energy sources for various real time applications. Also, there is the need for much research on refrigerant charge amount of cascade heat pumps, refrigerant-refrigerant heat exchangers to be used as cascade heat exchanger, cascade heat pumps for simultaneous cooling, heating and hot water generation and on the use of variable speed compressors and their control strategies in matching system capacity especially at part load conditions.

关键词： cascade heat pump low stage high stage optimization system performance refrigerant

Impulse force reductions and their effects on WBV exposures in high impact shovel loading operations

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International Journal of Mining Science and Technology 2018年第3期28卷 423-435页

作者： Danish Ali samuel Frimpong Mining & Nuclear Engineering Department Missouri University of Science and Technology

When shovels load the dump trucks with over 100-ton passes under gravity dumping conditions, they will create a large impact force on the dump truck body which generates high frequency shock waves which expose the operators to whole body vibrations （WBV）. The main cause of such truck vibrations is the large impact force due to the gravity dumping of large tonnage passes. Therefore a rigorous mathematical model has been developed for the impact force containing all the necessary factors upon which it depends. Latter, a thorough analysis shows that percentage reduction of 7.19%, 9.40%, 13.27%, 14.8%, 17.30% and 18.13% can he achieved by reducing the dumping distance to 6.33 m, 6.0 m, 5.5 m, 5.33 m, 5.0 m and 4.9 m, respectively, as compared to when the dumping distance was 7.33 m. Even more reduction in the magnitude of impact force can he observed if the shovel pass gets divided into more than two sub-passes. Therefore, these models can he used to figure out the number of sub-passes into which a single ore pass can he divided and/or the extent to which the dumping distance can he reduced which would reduce the impact force significantly enough to obtain safer yet economic operations.

关键词： Impact force HISLO Mathematical modeling Dumping distance Shovel ore sub-passes

Multiclass stand-alone and ensemble machine learning algorithms utilised to classify soils based on their physico-chemical characteristics

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第2期14卷 603-615页

作者： Eyo Eyo samuel Abbey Faculty of Environment and Technology Department of Geography and Environmental ManagementCivil Engineering ClusterUniversity of the West of EnglandBristolBS161QYUK Fugro GB Marine Geotechnical Services Limited WallingfordOX109RBUK

This study has provided an approach to classify soil using machine *** elements of stand-alone machine learning algorithms(*** regression(LR)and artificial neural network(ANN)),decision tree ensembles(*** forest(DF)and decision jungle(DJ)),and meta-ensemble models(*** ensemble(SE)and voting ensemble(VE))were used to classify soils based on their intrinsic physico-chemical ***,the multiclass prediction was carried out across multiple cross-validation(CV)methods,*** validation split(TVS),k-fold cross-validation(KFCV),and Monte Carlo cross-validation(MCCV).Results indicated that the soils’clay fraction(CF)had the most influence on the multiclass prediction of natural soils’plasticity while specific surface and carbonate content(CC)possessed the least within the nature of the dataset used in this ***-alone machine learning models(LR and ANN)produced relatively less accurate predictive performance(accuracy of 0.45,average precision of 0.5,and average recall of 0.44)compared to tree-based models(accuracy of 0.68,average precision of 0.71,and recall rate of 0.68),while the meta-ensembles(SE and VE)outperformed(accuracy of 0.75,average precision of 0.74,and average recall rate of 0.72)all the models utilised for multiclass *** analysis of the meta-ensembles proved their capacities to discriminate between soil classes across the methods of CV *** learning training and validation using MCCV and KFCV methods enabled better prediction while also ensuring that the dataset was not overfitted by the machine learning *** confirmation of this phenomenon was depicted by the continuous rise of the cumulative lift curve(LC)of the best performing models when using the MCCV ***,this study demonstrated that soil’s physico-chemical properties do have a direct influence on plastic behaviour and,therefore,can be relied upon to classify soils.

关键词： Soil classification Physico-chemistry Soil plasticity Machine learning Logistic regression(LR) Machine learning ensembles Artificial neural network(ANN)

Inspection of free energy functions in gradient crystal plasticity

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Acta Mechanica Sinica 2013年第6期29卷 763-772页

作者： samuel Forest Nicolas Guninchault Centre des Matriaux Mines ParisTechCNRS UMR 7633 BP 8791003 Evry CedexFrance

The dislocation density tensor computed as the cud of plastic distortion is regarded as a new constitutive variable in crystal plasticity. The dependence of the free energy function on the dislocation density tensor is explored starting from a quadratic ansatz. Rank one and logarithmic dependencies are then envisaged based on considerations from the statistical theory of dislocations. The rele- vance of the presented free energy potentials is evaluated from the corresponding analytical solutions of the periodic two-phase laminate problem under shear where one layer is a single crystal material undergoing single slip and the second one remains purely elastic.

关键词： Gradient plasticity Crystal plasticity Continuum thermodynamics Dislocation density tensor Read- Shockley energy

Kinematic Analysis of an Under-actuated,Closed-loop Front-end Assembly of a Dragline Manipulator

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International Journal of Automation and computing 2020年第4期17卷 527-538页

作者： Muhammad AWardeh samuel Frimpong Department of Mining and Nuclear Engineering Missouri University of Science and TechnologyRolla 65409USA Center for Infrastructure Engineering Studies Missouri University of Science and TechnologyRolla 65409USADepartment of Mining and Nuclear EngineeringMissouri University of Science and TechnologyRolla 65409USA

Dragline excavators are closed-loop mining manipulators that operate using a rigid multilink framework and rope and rigging system,which constitute its front-end *** arrangements of dragline front-end assembly provide the necessary motion of the dragline bucket within its operating *** assembly resembles a five-link closed kinematic chain that has two independent generalized coordinates of drag and hoist ropes and one dependent generalized coordinate of dump *** models failed to represent the actual closed loop of dragline front-end assembly,nor did they describe the maneuverability of dragline ropes under imposed geometric ***,a three degrees of freedom kinematic model of the dragline front-end is developed using the concept of generalized *** contains all relevant configuration and kinematic constraint conditions to perform complete digging and swinging *** model also uses three inputs of hoist and drag ropes linear and a rotational displacement of swinging along their *** inverse kinematics is resolved using a feedforward displacement algorithm coupled with the Newton-Raphson method to accurately estimate the trajectories of the *** trajectories are solved only during the digging phase and the singularity was eliminated using Baumgarte's stabilization technique(BST),with appropriate inequality constraint *** is shown that the feedforward displacement algorithm can produce accurate trajectories without the need to manually solve the inverse kinematics from the *** research findings are well in agreement with the dragline real operational limits and they contribute to the efficiency and the reduction in machine downtime due to better control strategies of the dragline cycles.

关键词： Dragline mining manipulator underactuated closed-loop mechanism generalized speeds Baumgarte's stabilization technique(BST) feedforward displacement