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Microstructural Characterization and Tensile Behavior of Rutile(TiO_2)-Reinforced AA6063 Aluminum Matrix Composites Prepared by Friction Stir Processing

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 52-62页

作者： Sahayam Joyson abraham isaac Dinaharan Jebaraj David Raja Selvam Esther Titilayo Akinlabi Department of Mechanical Engineering V V College of Engineering Department of Mechanical Engineering Science University of Johannesburg Auckland Park Kingsway Campus Department of Mechanical Engineering Karunya Institute of Technology and Sciences

Rutile(TiO_2) particle-reinforced aluminum matrix composites were prepared by friction stir processing. The microstructure was studied using conventional and advanced characterization techniques. TiO_2 particles were found to be dispersed uniformly in the composite. Clusters of TiO_2 particles were observed at a higher particle content of 18 vol%. The interface between the TiO_2 particle and the aluminum matrix was characterized by the absence of pores and reactive ***-grain boundaries, ultra-fine grains and dislocation density were observed in the composites. TiO_2 particles improved the mechanical properties of the composites. However, a drop in tensile strength was observed at a higher particle content due to cluster formation. All the prepared composites exhibited ductile mode of fracture.

关键词： Aluminum matrix composites Friction stir processing Rutile Microstructure Tensile strength

Protection effect of the anthraquinones, cassiatorin and aurantio-obtusin from seeds of Senna tora against cowpea weevil attack

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Asian Pacific Journal of Tropical Biomedicine 2018年第2期8卷 98-105页

作者： Valentine Chi Mbatchou Rita Akosua Dickson isaac Kingsley Amponsah abraham Yeboah Mensah Solomon Habtemariam Department of Applied Chemistry and Biochemistry University for Development Studies Navrongo Campus Department of Pharmacognosy Faculty of Pharmacy and Pharmaceutical Sciences Kwame Nkrumah University of Science and Technology Pharmacognosy Research Laboratories & Herbal Analysis Services UK University of Greenwich

Objetive: To explore the potential insecticidal, ovipositor deterrent and antifeedant effects of ethyl acetate extract of the seeds of Senna tora(Syn. Cassia tora) against cowpea weevil(Callosobruchus maculatus).Method: The activities were evaluated using standard *** these bioassays, the cowpea seeds were used directly as an insect feed. The activity of the extract and isolated compounds were tested at concentrations of 100, 200 and 300 μg/mL and compared to neem oil and cinnamaldehyde(as standard positive controls). Phytochemical analysis of the ethyl acetate extract was done through a number of chromatographic techniques and the structures of the isolated compounds were established through comprehensive spectroscopic analysis including 2 D-NMR and ESI-MS ***: Fractionation of the active ethyl acetate extract resulted in the isolation of one known anthraquinone,aurantio-obtusin(1) and a novel compound that was named as cassiatorin(2). Compounds1 and 2 showed comparable insect antifeedant properties with the positive controls while their insecticidal and ovipositor deterrent effects were far superior to the standard ***: It is thus concluded that Senna tora extracts and the isolated compounds(1 and2) may be employed in the postharvest management of stored cowpea seeds and as other crop protectants.

关键词： Senna tora Cassia tora Cassiatorin Aurantio-obtusin Insecticidal Ovipositor deterrent Antifeedant Cowpea weevil

Classifying rockburst with confidence:A novel conformal prediction approach

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International Journal of Mining Science and Technology 2024年第1期34卷 51-64页

作者： Bemah Ibrahim isaac Ahenkorah University of South Australia UniSA STEMSA 5000Australia

The scientific community recognizes the seriousness of rockbursts and the need for effective mitigation *** literature reports various successful applications of machine learning(ML)models for rockburst assessment;however,a significant question remains unanswered:How reliable are these models,and at what confidence level are classifications made?Typically,ML models output single rockburst grade even in the face of intricate and out-of-distribution samples,without any associated confidence *** the susceptibility of ML models to errors,it becomes imperative to quantify their uncertainty to prevent consequential *** address this issue,we propose a conformal prediction(CP)framework built on traditional ML models(extreme gradient boosting and random forest)to generate valid classifications of rockburst while producing a measure of confidence for its *** proposed framework guarantees marginal coverage and,in most cases,conditional coverage on the test *** CP was evaluated on a rockburst case in the Sanshandao Gold Mine in China,where it achieved high coverage and efficiency at applicable confidence ***,the CP identified several“confident”classifications from the traditional ML model as unreliable,necessitating expert verification for informed *** proposed framework improves the reliability and accuracy of rockburst assessments,with the potential to bolster user confidence.

关键词： Rockburst Machine learning Uncertainty quantification Conformal prediction

Effect of functional composite coating developed via sulphate and chloride process parameter on the UNS G10150 steel for structural and wear mitigation in defence application

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Defence Technology（防务技术） 2018年第3期14卷 196-203页

作者： Ojo Sunday isaac Fayomi Department of Mechanical Engineering Covenant University Department of Chemical Metallurgical and Materials Engineering Tshwane University of Technology

The major engineering challenge of materials in defence technologies is the vulnerability of based metals to structural and wears deformation in service. In this paper, structural formation, mechanical and thermal stability behavior of developed composite coating of Zn-30 Al-7%Ti/Sn chloride bath and Zn-30 Al-7%Ti/Sn sulphate bath was investigated and compared to provide mitigation against failure. The thermal ageing property was done for 2 h at 600C via isothermal furnace. The structural, interfacial effect and stability behaviors of the co-deposited alloys were evaluated using scanning electron microscope equipped with energy dispersive spectrometer(SEM/EDS), atomic force microscope(AFM) and Xray diffractometer(XRD). The hardness and wear properties of the deposited coatings were examined with diamond base micro-hardness tester and reciprocating sliding tester respectively. The result shows that Zn-30 Al-7%Ti/Sn sulphate co-deposition contributed to increase hardness and wear resistance than Zn-30 Al-7%Ti/Sn chloride bath alloy. The stable crystal growth and significant performance of Zn-30 Al-7%Ti/Sn sulphate are link to the intermetallic phase hybrid of Zn Al, Zn4 Ti Al2, Zn3 Al Ti. Besides, it was observed that Zn-30 Al-7%Ti/Sn sulphate has excellent thermomechanical stability at harsh temperature,due to the deposition of Sn/Ti on steel; leading to formation of super-hard interface. However, it was established that co-deposition of mild steel with Zn-30 Al-7%Ti/Sn in sulphate bath significantly improved the structural and wear performance. It was shown that the hardness and wear of the developed composite Zn-30 Al-7%Ti/Sn is increased by about 80% compared to as received sample and about 25% compared with Zn-30 Al-7%Ti/Sn chloride coating developed. The improvement was proved to be an interference of zinc-composite growth. Thus, this work shows that sulphate induced Zn-30 Al-7%Ti/Sn via generation of controllable process parameter can provide significant improv

关键词：防卫技术硫酸盐氯化物低碳钢结构涂层合成 UNS

Pharmacognostic standardisation of Hilleria latifolia(Lam.) ***.(Phytolaccaceae)

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Asian Pacific Journal of Tropical Biomedicine 2014年第12期4卷 941-946页

作者： isaac Kingsley Amponsah abraham Yeboah Mensah Antonia Otoo Merlin Lincoln Kwao Mensah Jato Jonathan Department of Pharmacognosy Faculty of Pharmacy and Pharmaceutical SciencesKwame Nkrumah University of Science and Technology Department of Herbal Medicine Faculty of Pharmacy and Pharmaceutical Sciences.Kwame Nkrumah University of Science and Technology

Objective:To establish the pharmacognostic characters for the correct identification and quality control of Hilleria latifolia(***),an important herb in Ghanaian folklore medicine,for the treatment of infections,pain and ***:The macro-morphological,qualitative and quantitative microscopic features,physicochemical and phytochemical features of the medicinally used parts of *** were evaluated using standard ***:The plant has simple,alternate leaves with entire *** lamina is ovate to broadly lanceolate with an acuminate *** is hypostomatic with anomocytie *** plant contains abundant prismatic crystals in all *** grains abound in the *** quantitative indices of the leaf and physicochemical parameters have also been ***:The pharmacognostic features established in this study may be used as part of the pharmacopoeia! standard for the correct identification and quality control of ***.

关键词： Hilleria latifolia Pharmacognostic features standardization Thin layer chromatography chromatogram Quantitative microscopy Fluorescence analysis

HyDeploy:The UK’s First Hydrogen Blending Deployment Project

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Clean Energy 2019年第2期3卷 114-125页

作者： Tommy isaac Principal Engineer Progressive Energy LtdSwan House-Bonds MillsStonehouseGloucestershire GL103RFUK

The HyDeploy project is the UK’s first practical project to demonstrate that hydrogen can be safely blended into the natural-gas distribution system without requiring changes to appliances and the associated *** project is funded under Ofgem’s Network Innovation Competition and is a collaboration between Cadent Gas,Northern Gas Networks,Progressive Energy Ltd,Keele University(Keele),Health&Safety Laboratory and ITM *** and Northern Gas Networks are the Gas Distribution Network sponsors of the *** University is the host site,providing the gas-distribution network,which will receive the hydrogen *** University is the largest campus university in the ***&Safety Laboratory provides the scientific laboratories and experimental *** Power provides the electrolyser that produces the *** Energy Ltd is the project developer and project *** is structured into three distinct *** first is an extensive technical programme to establish the necessary detailed evidence base in support of an application to the Health&Safety Executive for Exemption to Schedule 3 of the Gas Safety(Management)Regulations(GS(M)R)to permit the injection of hydrogen at 20 mol%.This is required to allow hydrogen to be blended into a natural-gas supply above the current British limit of 0.1 mol%.The second phase comprises the construction of the electrolyser and grid entry unit,along with the necessary piping and valves,to allow hydrogen to be mixed and injected into the Keele University gas-distribution network and to ensure all necessary training of operatives is conducted before *** third phase is the trial itself,which is due to start in the summer of 2019 and last around 10 *** trial phase also provides an opportunity to undertake further experimental activities related to the operational network to support the pathway to full deployment of blended *** outcome of HyDeploy is principally develo

关键词： HyDeploy hydrogen blending demonstration project

Design for a specified natural frequency of elastically constrained axially graded bars

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Acta Mechanica Sinica 2010年第2期26卷 313-316页

作者： isaac Elishakoff Jason Yost Department of Mechanical Engineering Florida Atlantic University

This study derives some closed-form analytic as well as numeric solutions for the axially graded elasticallyconstrained bar with polynomial varying modulus of elasticity, along the axial coordinate. The solutions allo... 详细信息

关键词： Graded bars Vibration Natural frequency

Lipopolysaccharide mouse models for Parkinson's disease research:a critical appraisal

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Neural Regeneration Research 2022年第11期17卷 2413-2417页

作者： isaac Deng Larisa Bobrovskaya Health and Biomedical Innovation Clinical and Health SciencesUniversity of South AustraliaAdelaideAustralia

Parkinson's disease,the most common movement disorder,has a strong neuroinflammatory *** is evident by increased pro-inflammatory cytokines in the serum,and the presence of activated microglial cells,and inflammatory cytokines in the substantia nigra of post-mortem brains as well as cerebrospinal fluid of Parkinson's disease *** central and peripheral neuroinflammatory aspects of Parkinson's disease can be investigated in vivo via administration of the inflammagen lipopolysaccharide,a component of the cell wall of gram-negative *** this mini-review,we will critically evaluate different routes of lipopolysaccharide administration(including intranasal systemic and ste reotasic),their relevance to clinical Parkinson's disease as well as the recent findings in lipopolysaccharide mouse *** will also share our own expe riences with systemic and intrastriatal lipopolysaccharide models in C57BL/6 mice and will discuss the usefulness of lipopolysaccharide mouse models for future research in the field.

关键词： C57BL/6 mice intranasal models lipopolysaccharide models neuroinflammation Parkinson's disease stereotaxic models substantia nigra systemic models

Infection,Pain,and Itch

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Neuroscience Bulletin 2018年第1期34卷 109-119页

作者： isaac M.Chiu Department of Microbiology and Immunobiology Division of Immunology Harvard Medical School

Pain and itch are unpleasant sensations that often accompany infections caused by viral, bacterial, parasitic, and fungal pathogens. Recent studies show that sensory neurons are able to directly detect pathogens to mediate pain and itch. Nociceptor and pruriceptor neurons respond to pathogen-associated molecular patterns, including Toll-like receptor ligands, N-formyl peptides, and bacterial toxins. Other pathogens are able to silence neuronal activity to produce analgesia during infection. Pain and itch could lead to neuronal modulation of the immune system or behavioral avoidance of future patho- gen exposure. Conversely, pathogens could modulate neuronal signaling to potentiate their pathogenesis and facilitate their spread to other hosts. Defining how pathogens modulate pain and itch has critical implications for sensory neurobiology and our understanding of host- microbe interactions.

关键词： Pain Itch Bacteria Pathogens Infection Inflammation Viruses