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Dynamic modeling of a three-dimensional braided composite thin plate considering braiding directions

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 123-138页

作者： Chentong GAO Huiyu SUN Jianping GU W.m.HUANG College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics School of mechanical and Aerospace Engineering Nanyang Technological University Jiangsu Key Laboratory of Advanced Structural materials and Application Technology School of Materials Science and EngineeringNanjing Institute of Technology

Currently, there are a limited number of dynamic models available for braided composite plates with large overall motions, despite the incorporation of three-dimensional(3D) braided composites into rotating blade components. In this paper, a dynamic model of 3D 4-directional braided composite thin plates considering braiding directions is established. based on Kirchhoff's plate assumptions, the displacement variables of the plate are expressed. by incorporating the braiding directions into the constitutive equation of the braided composites, the dynamic model of the plate considering braiding directions is obtained. The effects of the speeds, braiding directions, and braided angles on the responses of the plate with fixed-axis rotation and translational motion, respectively, are investigated. This paper presents a dynamic theory for calculating the deformation of 3D braided composite structures undergoing both translational and rotational motions. It also provides a simulation method for investigating the dynamic behavior of non-isotropic material plates in various applications.

关键词： Constitutive equations

Assembling structurally customizable synthetic carriers of si RNA through thermodynamically self-regulated process

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Asian Journal of Pharmaceutical Sciences 2020年第3期15卷 356-364页

作者： Guang bai Tong Xue Xiaotao Dong uday Kumar Chinta Jia Feng Tuo Jin Fei Wu School of Pharmacy Shanghai Jiao Tong UniversityShanghai 200240China

This study demonstrates that our previously reported polywraplex, a synthetic siRNA carrier consisting of a uni-molecular polyplex core of customizable size and a self-assembled triblock copolymer envelop, may be constructed using dendrimers as the crosslinking junctions. Replacing the branched low molecular weight PEI with polyamidoamine(PAmAm) dendrimer in the zeta potential regulated polymerization resulted in the similar network structured cationic polymer with electron microscopically visible crosslinking junctions. This visibility may offer a convenient way to characterize the molecular structure of the rationally designed networked siRNA-packing cationic polymer without altering its chemical properties and biologic functions. A series of physical-chemical characterizations and biological assays, comprising size, zeta potential, pre-phagocytic siRNA leaking and degradation, and silencing of functional genes, confirmed that the advanced properties of polywraplexes remained with the dendrimer junctions. Although sixth generation PAmAm dendrimer was used as the crosslinking junctions in the size-customizable polymerization for electron microscopic observation, lower generation dendrimer should also work in case more practical and structurally defined cationic polymer is needed.

关键词： Networked cationic polymer Thermodynamically self-regulated processes siRNA delivery Unimolecular polyplex Zeta potential regulated polymerization

Reliability modeling of hydraulic system of drum shearer machine

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Journal of Coal Science & Engineering(China) 2011年第4期17卷 450-456页

作者： SEYED HADI Hoseinie mOHAmmAD Ataie REZA Khalookakaei uday Kumar Faculty of mining Petroleum ＆ Geophysics Shahrood University of Technology Shahrood *** Iran Division of Operation and maintenance Engineering Lulea University of Technology Lulea 97187 Sweden

The hydraulic system plays an important role in supplying power and its transition to other working parts of a coal shearer machine. In this paper, the reliability of the hydraulic system of a drum shearer was analyzed. A case study was done in the Tabas Coal mine in Iran for failure data collection. The results of the statistical analysis show that the time between failures （TbF） data of this system followed the 3-parameters Weibull distribution. There is about a 54% chance that the hydraulic system of the drum shearer will not fail for the first 50 h of operation. The developed model shows that the reliability of the hydraulic system reduces to a zero value after approximately 1 650 hours of operation. The failure rate of this system decreases when time increases. Therefore, corrective maintenance （run-to-t^ailure） was selected as the best maintenance strategy for it.

关键词： reliability modeling hydraulic system drum shearer maintenance strategy

Spontaneous combustion of coals and coal-shales

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International Journal of mining Science and Technology 2018年第6期28卷 933-940页

作者： m.Onifade b.Genc The School of mining Engineering University of the Witwatersrand

Spontaneous combustion of coal is a well-known phenomena around the globe. Apart from the coal itself,burning coal-shales is becoming a problem in the South African coal mines. Serious incidents of spontaneous combustion have been reported as a result of self-heating of reactive coal-shales. The intrinsic properties and spontaneous combustion tests of 28 selected coal and coal-shale samples were conducted and a relationship between the two has been established. Intrinsic properties were obtained by using the proximate and ultimate analysis, and spontaneous combustion liability tests results were obtained by using the Wits-Ehac and Wits-CT indices. The experimental results show that intrinsic properties of these materials complement to the spontaneous combustion liability tests results. Comparative analyses of intrinsic properties and spontaneous combustion characteristics indicate similarities between the mechanism of coal oxidation and that of the oxidative processes undergone by coal-shales. For the tested samples, coal samples have a higher intrinsic spontaneous combustion reactivity rating than the ***, an increase in carbon, moisture, hydrogen, volatile matter, nitrogen and a decrease in ash content indicate an increased proneness to self-heating. The concentration of pyrite found in the coal-shales accelerates self-heating. The event of spontaneous combustion can occur if coal-shales absorb sufficient oxygen when subjected to atmospheric conditions.

关键词： Spontaneous combustion Coal-shales Proximate and ultimate analysis Wits-Ehac index Wits-CT index

Cooling pathways for deep Australian longwall coal mines of the future

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International Journal of mining Science and Technology 2018年第6期28卷 865-875页

作者： b.belle m.biffi Anglo American Coal QueenslandAustralia Department of mining Engineering UNSWSydneyNSW 2052Australia Anglo American Operations(Pty)Ltd. Johannesburg 2001South Africa

Cooling of coal mines in the bowen basin, characterized by steep geothermal gradient, is presently achieved mostly through rental surface bulk air cooling in summer months. This paper argues that future mines will be required to focus their cooling resources more intensively to manage a challenging thermal environment where virgin coal temperatures over 50 °C at a depth of 500 m are expected. Currently, mine cooling systems are employed to maintain the wet bulb temperatures(WbT) to below 27 °C at which point the risks of heat stroke or other heat related issues are manageable. The capacities of these systems are in the range of 6–10 mW refrigeration power. The relationship between high working temperature environment and injury frequency rates is well established. Therefore, provision of appropriate cooling strategies and understanding their optimum performance and suitability are important to Australian coal mines of the future. This paper evaluates the underground temperature profiles of deep, gassy coal mines with propensity for spontaneous combustion and proposes the long term cooling pathways to effectively manage the thermal hazards. Thermodynamic modeling is performed on a longwall face and includes air leakage effects from goaf streams at various locations along the longwall face. The strategy summarizes the application of underground bulk air cooling, chilled water sprays on the shearer and the resulting temperature profiles. Considering the new mining projects planned for the bowen basin region, a review of implementable cooling strategies such as mid-gate mobile bulk air coolers(bACs), spot coolers, underground bulk air cooling and the use of chilled water to enhance the positional efficiency of cooling plants,are discussed in this paper. Finally, the comparison of ‘rental' versus ‘ownership' of cooling plants is analysed as part of long-term cooling strategies.

关键词： Cooling Chilled water Underground Positional efficiency Thermal hazard

A review of light amplification by stimulated emission of radiation in oil and gas well drilling

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mining Science and Technology 2010年第5期20卷 752-757页

作者： OLALEYE b m Department of mining Engineering Federal University of Technology

The prospect of employing Light Amplification by Stimulated Emission of Radiation(LASER) for well drilling in oil and gas industry was *** this work,the experimental works carried out on various oil well drilling operations was *** results show that,LASER or LASER-aided oil and gas well drilling has many potential advantages over conventional rotary drilling,including high penetration rate,reduction or elimination of tripping,casing,bit costs,enhanced well control,as well as perforating and side-tracking *** investigation also reveals that modern infrared LASERs have a higher rate of rock cuttings removal than that of conventional rotary drilling and flame-jet *** also reveals that LASER can destroy rock without damaging formation permeability but rather,it enhances or improves permeability and that permeability and porosity increases in all rock *** paper has therefore provided more knowledge on the potential value to drilling operations and techniques using LASER.

关键词： LASER oil gas well drilling simulation specific energy spallation

Emerging role of A-kinase anchoring protein 5 signaling in reward circuit function

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Neural Regeneration Research 2025年第10期20卷 2913-2914页

作者： William J.Flerlage mark L.Dell’Acqua brian m.Cox Fereshteh S.Nugent Uniformed Services University of the Health Sciences Department of Pharmacology and Molecular TherapeuticsBethesdaMDUSA Department of Pharmacology University of Colorado School of MedicineAnschutz Medical CampusAuroraCOUSA

There is a strong evidence supporting the hypothesis of synaptic dysfunction as a major contributor to neural circuit and network disruption underlying emotional and mood dysregulation in psychiatric disorders(Simmons et al.,2024).Diverse sets of distinct molecular signaling pathways converge on the synapse to regulate synaptogenesis,synaptic function,and synaptic plasticity in brain regions and circuits through complex interactions organized by numerous multivalent protein scaffolds,including the family of proteins known as A-kinase anchoring proteins(AKAPs).

关键词： function supporting

Sample geometric mean versus sample median in closed form framework of seismic reliability evaluation: a case study comparison

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 187-201页

作者： m.Abyani b.Asgarian m.Zarrin Faculty of Civil Engineering K.N.Toosi University of Technology

Earthquake engineers have made a lot of efforts to derive a comprehensive set of closed form expressions for performance evaluation of frames, which are already presented in guidelines such as SAC/FEmA. These analytical expressions have been developed to estimate the annual probability of exceeding a limit state. In the process of such seismic assessments, some essential assumptions are adopted to simplify the process. One of these fundamental assumptions declares that drift demand at any seismic intensity level follows a lognormal distribution around its median. To investigate the validity of this assumption, this paper describes a case study of the types of errors that could be produced by using the sample median as the central tendency. based on the maximum Likelihood Estimation method as well as other statistical evidence, this paper proposes the use of the sample geometric mean instead of the sample median for the central tendency. Further, the results of seismic reliability evaluations of 4 sample frames are compared based on utilizing both the geometric mean and the sample median. In this process, both first and second order power law fits of the hazard curve are implemented to compare the effects of hazard estimation and the selection of the central tendency on the final results. It is observed in the application example that the sample geometric mean could lead to more accurate results.

关键词： seismic reliability closed-form expression SAC/FEmA limit state median geometric mean

Warm Deformation of Low Carbon Steel Using Forward Extrusion-Equal Channel Angular Pressing Technique

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Journal of Iron and Steel Research International 2013年第2期20卷 68-71页

作者： b Eghbali m Shaban Department of materials Science Engineering Sahand University of Technology

A combination of extrusion and equal channel angular pressing （ECAP） was used to deform a plain low carbon steel. This process consists of two successive deformations by extrusion and ECAP in a single die （Ex-ECAP）. Cylindrical samples were heated to predefined temperatures （650 and 850 ℃） and then pressed through a die channel with crosshead speed of 10 mm/s. microstructure and resultant mechanical properties of processed material were studied. The results showed that pressing temperature has a significant effect on the resultant microstructure. While at 650 ℃, the cold worked structure with elongated ferrite grains were obtained, and at 850 ℃ the microstructure consisted of elongated ferrite grains and very fine grains at their boundaries as a consequence of continuous dynamic recrystallization （CDRX） of ferrite phase. Also at 850 ℃, a particular microstructure consisted of cold worked ferrite and static recrystallized grains on shear bands was obtained.

关键词： extrusion equal channel angular pressing low carbon steel