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Solar wind entry via flux tube into magnetosphere observed by Cluster measurements at dayside magnetopause during southward IMF

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Science China(Technological Sciences) 2009年第7期52卷 2104-2111页

作者： M. dunlop A. Balogh H. Rème Y. V. Bogdanova A. Fazakerley Rutherford Appleton Laboratory Didcot United Kingdom Imperial College of Science Technology and Medicine London United Kingdom CESR BP4346 31028 Toulouse Cedex 4 France Mullard Space Science Laboratory Dorkink United Kingdom Department of Physics La Trobe University Victoria 3086 Australia

By analyzing hot ion and electron parameters together with magnetic field measurements from Cluster, an event of magnetopause crossing of the spacecraft has been investigated. At the latitude of about 40° and magnetic local time (MLT) of 13:20 during the southward interplanetary magnetic field (IMF), a transition layer was observed, with the magnetospheric field configuration and cold dense plasma features of the magnetosheath. The particle energy-time spectrograms inside the layer were similar to but still a little different from those in the magnetosheath, obviously indicating the solar wind entry into the magnetosphere. The direction and magnitude of the accelerated ion flow implied that reconnection might possibly cause such a solar wind entry phenomenon. The bipolar signature of the normal magnetic component BN in magnetopause coordinates further supported happening of reconnection there. The solar wind plasma flowed toward the magnetopause and entered the magnetosphere along the reconnected flux tube. The magnetospheric branch of the reconnected flux tube was still inside the magnetosphere after reconnection and supplied the path for the solar wind entry into the dayside magnetosphere. The case analysis gives observational evidence and more details of how the reconnection process at the dayside low latitude magnetopause caused the solar wind entry into the magnetosphere.

关键词： transport process magnetic reconnection solar wind-magnetosphere interactions

Saturation in wavelength-division multiplexing free-space optical communication systems

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Frontiers of Optoelectronics 2019年第2期12卷 197-207页

作者： Jeremiah O. BANDELE malcolm WOOLFSON Andrew J. PHILLIPS Department of Electrical Electronics and Computer Engineering College of EngineeringAfe Babalola UniversityAdo-EkitiEkiti StateP.M.B 5454Nigeria Department of Electrical and Electronic Engineering Faculty of EngineeringUniversity of Nottingham University ParkNottinghamNG7 2RDUK

The performance of a wavelength-division multiplexing (WDM) free-space optical (FSO) commu-nication system in a turbulent atmosphere employing optical amplifiers to improve capacity is investigated, in the presence of amplified spontaneous emission noise, scintillation, beam spreading, atmospheric attenuation and interchannel crosstalk. Using on-off keying modulation, Monte Carlo simulation techniques are used to obtain the average bit error rate and system capability due to scintillation and the effect of introducing a power control algorithm (PCA) to the system is investigated. The PCA ensures that at any receiving instant, the same turbulence- free powers are received by all the receiving lenses. The performance of various WDM FSO communication system configurations such as non-amplified systems with an adaptive decision threshold (NOAADT), non- amplified systems with a non-adaptive decision threshold, fixed gain amplified systems with an adaptive decision threshold, fixed gain amplified systems with a non- adaptive decision threshold and saturated gain amplified systems with a non-adaptive decision threshold (SOA- NADT) are investigated. Results obtained show that the SOANADT is superior to the NOAADT and the PCA is only beneficial in amplified systems.

关键词： wavelength-division multiplexing (WDM) free-space optical (FSO) communication crosstalk optical amplifier (OA) gain saturation decision threshold

POCl3 diffusion for industrial Si solar cell emitter formation

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Frontiers in Energy 2017年第1期11卷 42-51页

作者： Hongzhao LI Kyung KIM Brett HALLAM Bram HOEX Stuart WENHAM malcolm ABBOTT School of Photovoltaic and Renewable Energy Engineering UNSW Australia Sydney NSW 2052 Australia

POCl3 diffusion is currently the de facto standard method for industrial n-type emitter fabrication. In this study, we present the impact of the following processing parameters on emitter formation and electrical performance： deposition gas flow ratio, drive-in tempera- ture and duration, drive-in O2 flow rate, and thermal oxidation temperature. By showing their influence on the emitter doping profile and recombination activity, we provide an overall strategy for improving industrial POCl3 tube diffused emitters.

关键词： POCl3 diffusion emitter recombination oxidation silicon

Bridging wounds:tissue adhesives’essential mechanisms,synthesis and characterization,bioinspired adhesives and future perspectives

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Burns & Trauma 2022年第1期10卷 216-245页

作者： Kaige Xu Xiaozhuo Wu Xingying Zhang malcolm Xing Department of Mechanical Engineering University of ManitobaWinnipegManitoba R3T 2N2Canada

Bioadhesives act as a bridge in wound closure by forming an effective interface to protect against liquid and gas leakage and aid the stoppage of *** their credit,tissue adhesives have made an indelible impact on almost all wound-related *** unique properties include minimal damage to tissues,low chance of infection,ease of use and short wound-closure *** contrast,classic closures,like suturing and stapling,exhibit potential additional complications with long operation times and undesirable inflammatory *** tremendous progress has been made in the development of tissue adhesives,they are not yet ***,highlighting and summarizing existing adhesive designs and synthesis,and comparing the different products will contribute to future *** review first provides a summary of current commercial traditional tissue ***,based on adhesion interaction mechanisms,the tissue adhesives are categorized into three main types:adhesive patches that bind molecularly with tissue,tissuestitching adhesives based on pre-polymer or precursor solutions,and bioinspired or biomimetic tissue *** specific adhesion mechanisms,properties and related applications are *** adhesion mechanisms of commercial traditional adhesives as well as their limitations and shortcomings are also ***,we also discuss the future perspectives of tissue adhesives.

关键词： Adhesive patch Adhesion mechanism Nature-inspired Tissue adhesives Bioadhesives

Open-porous magnesium-based scaffolds withstand in vitro corrosion under cyclic loading:A mechanistic study

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Bioactive Materials 2023年第1期19卷 406-417页

作者： Roxane Bonithon Colin Lupton Marta Roldo Joseph Nicholas dunlop Gordon William Blunn Frank Witte Gianluca Tozzi Zeiss Global Centre School of Mechanical and Design EngineeringUniversity of PortsmouthAnglesea RoadPO13DJPortsmouthUnited Kingdom School of Pharmacy and Biomedical Sciences University of PortsmouthWhite Swan RoadPO12DTPortsmouthUnited Kingdom School of the Environment Geography&GeosciencesUniversity of PortsmouthBurnaby RoadPO13QLPortsmouthUnited Kingdom Department of Prosthodontics Geriatric Dentistry and Craniomandibular DisordersCharite-Universitätsmedizin BerlinAßmannshauser Straße 4-614197BerlinGermany Biotrics Bioimplants AG Ullsteinstr.10812109BerlinGermany

The successful application of magnesium(Mg)alloys as biodegradable bone substitutes for critical-sized defects may be comprised by their high degradation rate resulting in a loss of mechanical *** study investigates the degradation pattern of an open-porous fluoride-coated Mg-based scaffold immersed in circulating Hanks’Balanced Salt Solution(HBSS)with and without in situ cyclic compression(30 N/1 Hz).The changes in morphological and mechanical properties have been studied by combining in situ high-resolution X-ray computed tomography mechanics and digital volume *** in situ cyclic compression induced acceleration of the corrosion rate,probably due to local disruption of the coating layer where fatigue microcracks were formed,no critical failures in the overall scaffold were observed,indicating that the mechanical integrity of the Mg scaffolds was *** changes,due to the accumulation of corrosion debris between the scaffold fibres,resulted in a significant increase(p<0.05)in the material volume fraction from 0.52±0.07 to 0.47±0.03 after 14 days of ***,despite an increase in fibre material loss,the accumulated corrosion products appear to have led to an increase in Young’s modulus after 14 days as well as lower third principal strain(εp3)accumulation(-91000±6361μεand-60093±2414μεafter 2 and 14 days,respectively).Therefore,this innovative Mg scaffold design and composition provide a bone replacement,capable of sustaining mechanical loads in situ during the postoperative phase allowing new bone formation to be initially supported as the scaffold resorbs.

关键词： Magnesium alloys Bone regeneration In vitro corrosion X-ray computed tomography(XCT) Digital volume correlation(DVC)

Local-environment dependence of stacking fault energies in concentrated solid-solution alloys

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npj Computational Materials 2019年第1期5卷 1032-1038页

作者： Shijun Zhao Yuri Osetsky G.malcolm Stocks Yanwen Zhang Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Department of Mechanical Engineering City University of Hong KongHong KongChina Department of Materials Science and Engineering University of TennesseeKnoxvilleTN 37996USA

Concentrated solid-solution alloys(CSAs)based on 3d transition metals have demonstrated extraordinary mechanical properties and radiation resistance associated with their low stacking fault energies(SFEs).Owing to the intrinsic disorder,SFEs in CSAs exhibit distributions depending on local atomic *** this work,the distribution of SFEs in equiatomic CSAs of NiCo,NiFe,and NiCoCr are investigated based on empirical potential and first-principles *** show that the calculated distribution of SFEs in chemically disordered CSAs depends on the stacking fault area using empirical potential *** on electronic structure calculations,we find that local variations of SFEs in CSAs correlate with the charge density redistribution in the stacking fault *** further propose a bond breaking and forming model to understand and predict the SFEs in CSAs based on the local structure *** is shown that the perturbation induced by a stacking fault is localized in the first-nearest planes for NiCo,but extends up to the third nearest planes for NiFe and NiCoCr because of partially filled d electrons in Fe and Cr.

关键词： alloys fault stacking

Effect of operating pressure on the performance of THAI-CAPRI in situ combustion and in situ catalytic process for simultaneous thermal and catalytic upgrading of heavy oils and bitumen

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Petroleum Research 2022年第2期7卷 155-164页

作者： Muhammad Rabiu Ado malcolm Greaves Sean P.Rigby Department of Chemical Engineering College of EngineeringKing Faisal UniversityP.O.Box:380Al-Ahsa31982Saudi Arabia Department of Chemical and Environmental Engineering University of NottinghamUniversity ParkNottinghamNG72RDUK Department of Chemical Engineering University of BathClaverton DownBathBA27AYUK

According to the analysis of the 2020 estimates of the International Energy Agency(2020),the world will require up to 770 billion barrels of oil from now to ***,based on the British Petroleum(BP)statistical review of world energy 2020,the world-wide total reserve of the conventional light oil is only 520.2 billion barrels as at the end of *** implies that the remaining 249.8 billion barrels of oil urgently needed to ensure a smooth transition to a decarbonised global energy and economic systems is provided must come from unconventional oils(*** oils and bitumen)*** heavy oils and bitumen are very difficult to produce and the current commercial production technologies have poor efficiency and release large quantities of greenhouse ***,these resources should ideally be upgraded and produced using technologies that have greener *** is where the energy-efficient,environmentally friendly,and self-sustaining THAI-CAPRI coupled in situ combustion and in situ catalytic upgrading process comes ***,the novel THAI-CAPRI process is trialled only once at field and it has not gained wide recognition due to poor understanding of the optimal design parameters and ***,this work reports the first ever results of investigations of the effect of operating pressure on the performance of the THAI-CAPRI *** experimental scale numerical models of the process based on Athabasca tar sand properties were run at pressures of 8000 kPa and 500 kPa respectively using CMG *** study has shown that the higher the operating pressure,the larger the API gravity and the higher the cumulative volume of high-quality oil is produced(i.e.a 2300 cm3 of z24 oAPI oil produced at 8000 kPa versus the 2050 cm3 of z17.5 oAPI oil produced at 500 kPa).The study has further shown that despite presence of annular catalyst layer,the THAI-CAPRI process operates ***,it is found that a more stable and safer operation of th

关键词： Toe-to-heel air injection(THAI) Enhanced oil recovery(EOR) Reservoir simulation In situ combustion(ISC) Heavy oil/Bitumen/Tar sand In situ catalytic upgrading

Numerical simulation investigations of the applicability of THAI in situ combustion process in heavy oil reservoirs underlain by bottom water

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Petroleum Research 2023年第1期8卷 36-43页

The presence of a bottom water(BW)layer in heavy oil reservoirs can present substantial problems for efficient oil recovery for all recovery ***,it is necessary to know how particular production processes are affected by different BW layer thicknesses,and how standard production procedures can be adapted to handle such ***-to-heel air injection(THAI)is a thermally efficient process,generating in situ energy in the reservoir by burning a fraction of the oil-in-place as coke and has the potential to economically and environmentally friendly work in reservoirs with BW ***,to ascertain that,studies are needed *** are conducted via numerical simulations using commercial reservoir thermal simulator,CMG *** work has shown that the shape of the combustion zone in THAI remains forward-leaning even in the presence of a BW layer,indicating that the process is stable,and that there is no oxygen bypassing of the combustion ***,the oil recovery rate is highly negatively affected by how large the thickness of the BWzone is,and the severity of such effect is determined to be proportional to the thickness of the BW *** study also shows that there is a period of low oil production rate which corresponds to mobilised oil displacement into the BW zone which in turn causes a surge in water production *** practical implication of this is that prolonged period of low oil production rates will expose companies and/or investors to higher risk due to the oil market *** this study,it is also revealed that the height of the mobilised oil that is displaced into the BW zone equates to that of the displaced and replaced water thereby implying that when the BW layer thickness is 50%that of the oil layer(OL),less than 50%of the mobilised oil will be recovered when the entire reservoir is swept by the combustion ***,conclusively,applying the THAI process in its conventional form in reservoirs containing bott

关键词： In situ combustion(ISC) Enhanced oil recovery(EOR) Tar sand/heavy oil/bitumen Reservoir simulation Toe-to-heel air injection(THAI)

Preparation of MCM-41 in Industrial Scale and Its Application in Heavy Oil Processing

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Chemical Research in Chinese Universities 2002年第2期18卷 169-174页

作者： Jianwen Da Tiancun Xiao Jianming Su Xingzhong Xu malcolm L.H.Green Research Institute of Qilu Petrochem.Corp. Zibo 255400China The Wolfson Catalysis Centre Inorganic Chemistry LaboratoryUniversity of OxfordSouth Parks RoadOxfordOX13QRUK

A series of MCM 41 molecular sieves have been prepared on an industrial scale, and the effect of preparation factors such as aging temperature, pH values on the structure and pore distribution of the MCM 41 product have been studied by using X ray diffraction(XRD), thermogravimetric(TG) and electron microscopy(TEM). It is shown that the pH values have a significant effect on the crystallinity of the synthesized product. Under proper conditions, the MCM 41 prepared on an industrial scale has the same performance as the samples prepared on an Lab scale. The prepared MCM 41 was used as a modifier of zeolite Y for fluid catalytic cracking(FCC) of residual oil. It is shown that the addition of the MCM 41 in the zeolite Y catalyst increases the pore size, and surface area of the catalysts, which helps to increase the yield of gasoline and diesel and decrease the production of gaseous product and carbon deposition in the catalyst. The better performance of the MCM 41 modified zeolite Y catalyst is believed to be due to its adjustment on the acidity and increase of the pore size.

关键词： MCM-41 Industrial scale synthesis FCC catalyst