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Analysis of Classical Encryption Techniques in Cloud Computing

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Tsinghua Science and Technology 2016年第1期21卷 102-113页

作者： Muhammad Yasir Shabir Asif Iqbal Zahid mahmood Ata Ullah Ghafoor Department of Computer Science University of Management Science and Information School of Computer & Communication Engineering University of Science and TechnologyBeijing Department of Computer Science National University of Modern Languages

Cloud computing has become a significant computing model in the IT industry. In this emerging model,computing resources such as software, hardware, networking, and storage can be accessed anywhere in the world on a pay-per-use basis. However, storing sensitive data on un-trusted servers is a challenging issue for this model. To guarantee confidentiality and proper access control of outsourced sensitive data, classical encryption techniques are used. However, such access control schemes are not feasible in cloud computing because of their lack of flexibility, scalability, and fine-grained access control. Instead, Attribute-Based Encryption（ABE） techniques are used in the cloud. This paper extensively surveys all ABE schemes and creates a comparison table for the key criteria for these schemes in cloud applications.

关键词： cloud computing access control fine-grained access weighted attribute

Recent Progress,Challenges,and Prospects in Two‑Dimensional Photo‑Catalyst Materials and Environmental Remediation

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Nano-Micro Letters 2020年第12期12卷 29-105页

作者： Karim Khan Ayesha Khan Tareen Muhammad Aslam Rizwan Ur Rehman Sagar Bin Zhang Weichun Huang Asif mahmood Nasir mahmood Kishwar Khan Han Zhang Zhongyi Guo School of Electrical Engineering and Intelligentization Dongguan University of Technology(DGUT)Dongguan 523808GuangdongPeople’s Republic of China Institute of Microscale Optoelectronics Collaborative Innovation Centre for Optoelectronic Science and TechnologyKey Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen Key Laboratory of Micro‑Nano Photonic Information TechnologyGuangdong Laboratory of Artificial Intelligence and Digital Economy(SZ)Shenzhen UniversityShenzhen 518060People’s Republic of China College of Materials Science and Engineering Shenzhen UniversityShenzhen 518060People’s Republic of China Government Degree College Paharpur Gomel UniversityDera Ismail KhanK.P.KIslamic Republic of Pakistan School of Materials Science and Engineering Jiangxi University of Science and TechnologyJiangxi 341000People’s Republic of China School of Chemical and Bio‑Molecular Engineering The University of SydneySydneyNSW 2006Australia School of Engineering The Royal Melbourne Institute of Technology(RMIT)UniversityMelbourneVICAustralia Research Laboratory of Electronics(RLE) Massachusetts Institute of Technology(MIT)CambridgeMAUSA

The successful photo-catalyst library gives significant information on feature that affects photo-catalytic performance and proposes new *** is considerably significant to form multi-functional photo-catalysts with flexible *** recently,two-dimensional materials(2DMs)gained much attention from researchers,due to their unique thickness-dependent uses,mainly for photo-catalytic,outstanding chemical and physical ***-catalytic water splitting and hydrogen(H2)evolution by plentiful compounds as electron(e−)donors is estimated to participate in constructing clean method for solar *** photocatalysis received much research attention caused by their applications to tackle numerous energy and environmental *** broad review explains progress regarding 2DMs,significance in structure,and catalytic *** will discuss in detail current progresses of approaches for adjusting 2DMs-based photo-catalysts to assess their photo-activity including doping,hetero-structure scheme,and functional formation *** plans,e.g.,doping and sensitization of semiconducting 2DMs,increasing electrical conductance,improving catalytic active sites,strengthening interface coupling in semiconductors(SCs)2DMs,forming nano-structures,building multi-junction nano-composites,increasing photo-stability of SCs,and using combined results of adapted approaches,are summed ***,to further improve 2DMs photo-catalyst properties,hetero-structure design-based 2DMs’photo-catalyst basic mechanism is also reviewed.

关键词： Two-dimensional materials Photo-catalysts H2O2/H2-production Pollutant degradation CO2 reduction

In vitro bioactivity and corrosion of PLGA/hardystonite composite-coated magnesium-based nanocomposite for implant applications

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International Journal of Minerals,Metallurgy and Materials 2021年第1期28卷 168-178页

作者： mahmood Razzaghi Masoud Kasiri-Asgarani Hamid Reza Bakhsheshi-Rad Hamid Ghayour Advanced Materials Research Center Department of Materials EngineeringNajafabad BranchIslamic Azad UniversityNajafabadIran

A type of polymer/ceramic coating was introduced on a magnesium-based nanocomposite, and the nanocomposite was evaluated for implant *** microstructure, corrosion, and bioactivity of the coated and uncoated samples were *** alloying followed by sintering was applied to fabricate the Mg–3Zn–0.5Ag–15NiTi nanocomposite ***, different contents of poly(lactic-co-glycolic acid)(PLGA) coatings were studied, and 10 wt% of PLGA content was *** scanning electron microscopy(SEM) images of the bulk nanocomposite showed an acceptable homogenous dispersion of the Ni Ti nanoparticles(NPs) in the Mg-based *** the in vitro bioactivity evaluation, following the immersion of the uncoated and coated samples in a simulated body fluid(SBF) solution, the Ca/P atomic ratio demonstrated that the apatite formation amount on the coated sample was greater than that on the uncoated ***, assessing the corrosion resistance indicated that the coatings on the Mg-based substrate led to a corrosion current density(icorr) that was considerably lower than that of the *** a condition revealed that the coating would provide an obstacle for the *** on this study, the PLGA/hardystonite(HT) composite-coated Mg–3Zn–0.5Ag–15NiTi nanocomposite may be suitably applied as an orthopedic implant biomaterial.

关键词： magnesium nanocomposite corrosion biocompatibility poly(lactic-co-glycolic acid) hardystonite

Comparison of bioavailability and pharmacokinetics of diclofenac sodium and diclofenac potassium in normal and dehydrated rabbits

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药学学报 2009年第1期44卷 80-84页

作者： mahmood AHMAD Muhammad IQBAL Ghulam MURTAZA Department of Pharmacy Faculty of Pharmacy and Alternative Medicines the lslamia University of Bahawalpur Bahawalpur 63100 Pakistan

Two different salts of diclofenac,diclofenac sodium and diclofenac potassium,in tablet dosage form were tested for their bioavailability and disposition kinetics in a group of eighteen rabbits in normal and experimentally induced dehydrated conditions with a wash out period of 7 days between both stages of *** and physiological parameters were also measured in both normal and dehydrated *** levels in plasma were determined using a validated reversed phase HPLC *** kinetic parameters ***0-∞,Cmax,Tmax and other disposition kinetics were obtained with non-compartmental *** parameters *** cell volume,plasma glucose and total lipid concentration in dehydrated rabbits increased *** concentration of diclofenac sodium and diclofenac potassium decreased significantly in water deprived *** comparison,diclofenac potassium in normal and dehydrated state of the same group of rabbits showed a significantly increased plasma concentration when compared with diclofenac sodium.

关键词：生物药效率药物动力学药物化学生物化学

Reduction of local scour at river confluences using a collar

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International Journal of Sediment Research 2017年第3期32卷 364-372页

作者： Nargess Amini Behnam Balouchi mahmood Shafai Bejestan Department of Civil Geological and Mining Engineering Ecole polytechnique de Montréal Department of Hydraulic Structure School of Water Engineering Shahid Chaman University of Ahvaz Department of Water and Environmental Engineering School of Civil Engineering Shiraz University

River confluences(RCs) are important features within river systems where the three dimensional(3 D)flow structures and the downstream mixing of flows can cause deep scour holes. Despite this, few methods have been proposed to control scouring at RCs. In this study, application of a collar was experimentally examined for local scour control at the point where two rivers flow together. In particular, experimental tests were done with and without collar application at three different locations. The results reveal that the scour depth is directly proportional to the discharge ratio, i.e. the ratio of lateral discharge to that in the channel downstream of the confluence, and the densimetric Froude number(Frg).In addition, installation of a collar at RCs can decrease the scour depth up to 100%, thus completely avoiding the scour process. The results also show that by increasing the Frg the optimal installation location for a collar changes and moves towards the river bed level. Using a collar can also reduce the height of the point bar formed downstream of the confluence. The outcomes of the study allow derivation of an equation for predicting scour depth when a collar is applied as a countermeasure. The analysis of this equation shows that the estimates are mostly affected by the Frg.

关键词： Scour River confluence Discharge ratio Densimetric Froude number Collar

Bed expansion behavior and sensitivity analysis for super-high-rate anaerobic bioreactor

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第2期11卷 79-86页

作者： Xiao-guang CHEN Ping ZHENG Jing CAI mahmood QAISAR Department of Environmental Engineering Zhejiang University Hangzhou 310029 China Department of Environmental Sciences COMSA TS University A bbottabad 22060 Pakistan

Bed expansion behavior and sensitivity analysis for super-high-rate anaerobic bioreactor （SAB） were performed based on bed expansion ratio （E）, maximum bed sludge content （Vpmax）, and maximum bed contact time between sludge and liquid （Tmax）. Bed expansion behavior models were established under bed unfluidization, fluidization, and transportation states. Under unfluidization state, Ewas 0, Vprnax was 4867 ml, and rmax was 844-3800 s. Under fluidization state, E, Vpmax, and Tmax were 5.28%-255.69%, 1368-4559 ml, and 104-732 s, respectively. Under transportation state, washout of granular sludge occurred and destabilized the SAB. During stable running of SAB under fluidization state, E correlated positively with superficial gas and liquid velocities （Ug and ul）, while Vpmax and Tmax correlated negatively. For E and Vpmax, the sensitivities of ug and ul were close to each other, while for Tmax, the sensitivity of ur was greater than that of Ug. The prediction from these models was a close match to the experimental data.

关键词： Anaerobic bioreactor Expansion behaviors Bed expansion ratio Fluidization state Sensitivity analysis

Transient mixed convection flow arising due to thermal and mass diffusion over porous sensor surface inside squeezing horizontal channel

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Applied Mathematics and Mechanics(English Edition) 2013年第1期34卷 97-112页

作者： M.mahmood S.ASGHAR M.A.HOSSAIN Department of Mathematics COMSATS Institute of Information TechnologyPark RoadChak ShahzadIslamabad 44000Pakistan

The double diffusion effect on the mixed convection flow over a horizontal porous sensor surface placed inside a horizontal channel is analyzed. With the appropriate transformations, the unsteady equations governing the flow are reduced to non-similar boundary layer equations which are solved numerically for the time-dependent mixed convection parameter. The asymptotic solutions are obtained for small and large values of the time-dependent mixed convection parameter. The results are discussed in terms of the skin friction, the heat transfer coefficient, the mass transfer coefficient, and the velocity, temperature, and concentration profiles for different values of the Prandtl number, the Schmidt number, the squeezing index, and the mixed convection parameter.

关键词： squeezed flow mass transfer mixed convection horizontal surface

Insoluble additives for enhancing a blood-like liquid flow in micro-channels

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Journal of Hydrodynamics 2017年第1期29卷 144-153页

作者： Hayder A.Abdulbari Fiona Ling Wang Ming Wafaa K.mahmood Center of Excellence for Advanced Research in Fluid Flow Universiti Malaysia PahangGambang 26300KuantanPahangMalaysia Faculty of Chemical Engineering and Natural Resources University Malaysia PahangLebuhraya Tun Razak 26300 KuantanPahangMalaysia

This study introduces an approach for flow enhancement in the bloodstream using insoluble additives as non-degradable drag reducing agents that can replace the polymeric soluble additives. An open micro-channel liquid flow system with three different channel sizes was assembled and used to test the drag reduction performances of the solutions investigated. Three different nano- powders （with five different addition concentrations） were investigated and used to form solutions of artificial blood with blood-like rheological properties. The experimental results showed that the optimum drag reduction performance was achieved using bismuth III oxides （65%） for a 200 ppm concentration solution flowing through a 100 μm channel, while titanium IV oxides and fumed silica achieved 57 and 55% drag reduction for a 200 ppm concentration solution flowing in a 50 ktm channel, respectively.

关键词： Microchannels pressure drop drag reduction nano-powder additives

MgCl2/Et3N Base System as a New Catalyst for the Synthesis of a-Hydroxyphosphonate

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Chinese Journal of Chemistry 2012年第4期30卷 827-829页

作者： Tajbakhsh, mahmood Khaksar, Samad Tafazoli, Zahra Bekhradnia, Ahmadreza Chemistry Department University of Mazandaran P. O. Box 453 Babolsar Iran Chemistry Department Ayatollah Amoli Branch Islamic Azad University Amol Iran Chemistry Department Payame Noor University Sari Iran Pharmaceuttcal Sctences Research Center Department of Medicinal Chemistry Mazandaran University of Medical Sciences Sari Iran

An efficient and simple synthesis of a-hydroxyphosphonates via reaction of aldehydes and ketones with di- methylphosphite in the presence of MgCI2/Et3N base system is reported. The use of readily available and easy to... 详细信息

关键词： a-hydroxy phosphonates MgC12/Et3N ketones nucleophilic addition