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Resolving the Routine Presence of Kyanite, Andalusite and Sillimanite across a Region using Foliation Intersection/Inflection Axes Preserved in Porphyroblasts, Petrographic Observations and Thermobarometry

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Acta Geologica Sinica(English Edition) 2012年第5期86卷 1241-1250页

作者： asghar ali School of Earth and Environmental Science James Cook University Townsville Queensland 4811 Australia Department of Geology University of Peshawar Peshawar Khyber Pakhtunkhwa 25120 Pakistan

Constraints from P-T pseudosections （MnNCKFMASH system）, foliation intersection/ inflection axes preserved in porphyroblasts （FIAs）, mineral assemblages and textural relationships for rocks containing all three Al2 SiO5 polymorphs indicate a kyanite→ andalusite→ sillimanite sequential formation at different times rather than stable coexistence at the Al2SiO5 triple point. All three Al2SiO5 polymorphs grew in the Chl, Bt, Ms, Grt, St, Pl and Crd bearing Ordovician Clayhole Schist in Balcooma, northeastern Australia separately along a looped P-T-t-D path that swaps from clockwise to anticlockwise in the tectono-metamorphic history of the region. Kyanite grew during crustal thickening in an Early Silurian Orogenic event followed by decompression/heating, andalusite and fibrolitic sillimanite growth during Early Devonian exhumation.

关键词： Al2SiO5 triple point microtextures foliation intersection/inflection axes Barrovian sequence episodic porphyroblast growth

A discrete element model for simulating saturated granular soil

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Particuology 2011年第6期9卷 650-658页

作者： ali asghar Mirghasemi School of Civil Engineering College of Engineering University of Tehran

A numerical model is developed to simulate saturated granular soil, based on the discrete element method. Soil particles are represented by Lagrangian discrete elements, and pore fluid, by appropriate discrete elements which represent alternately Lagrangian mass of water and Eulerian volume of space. Macroscale behavior of the model is verified by simulating undrained biaxial compression tests. Micro-scale behavior is compared to previous literature through pore pressure pattern visualization during shear tests. It is demonstrated that dynamic pore pressure patterns are generated by superposed stress waves. These pore-pressure patterns travel much faster than average drainage rate of the pore fluid and may initiate soil fabric change, ultimately leading to liquefaction in loose sands. Thus, this work demonstrates a tool to roughly link dvnamic stress wave patterns to initiation of liQuefaction nhenomena.

关键词： Discrete element method Granular soil Saturated soil Pore pressure

Energy Efficiency in ARQ-Based Multi-Hop Systems and the Tradeoff with Throughput

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China Communications 2023年第6期20卷 60-71页

作者： ali asghar Haghighi Electrical and Computer Engineering Group Golpayegan College of EngineeringIsfahan University of TechnologyGolpayegan 87717-67498Iran

The minimum energy per bit(EPB)as the energy efficiency(EE)metric in an automatic retransmission request(ARQ)based multi-hop system is analyzed under power and throughput *** ARQ protocols including type-I(ARQ-I)and repetition redundancy(ARQ-RR)are considered and expressions for the optimal power allocation(PA)are *** the obtained optimal powers,the EE-throughput tradeoff(EETT)is analyzed and the EETT closed-form expressions for both ARQ protocols and in arbitrary average channel gain values are *** is shown that how different throughput requirements,especially the high levels,affect the EE ***,asymptotic analysis is made in the feasible high throughput values and lower and upper EETT bounds are derived for ARQ-I *** evaluate the EE a distributed PA scenario,as a benchmark,is presented and the energy savinggain obtained from the optimal PA in comparison with the distributed PA for ARQ-I and ARQ-RR protocols is discussed in different throughput values and node locations.

关键词： ARQ cooperative relaying energy efficiency green communication multi-hop systems routing algorithms throughput analysis

Particle shape consideration in numerical simulation of assemblies of irregularly shaped particles

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Particuology 2011年第4期9卷 387-397页

作者： Saba Abedi ali asghar Mirghasemi School of Civil Engineering College of Engineering University of Tehran

The mechanical behavior of granular materials depends much on the shape of the constituent particles. Therefore appropriate modeling of particle, or grain, shape is quite important. This study employed the method of direct modeling of grain shape （Matsushima ＆ Saomto, 2002）, in which, the real shape of a grain is modeled by combining arbitrary number of overlapping circular elements which are connected to each other in a rigid way. Then, accordingly, a discrete-element program is used to simulate the assembly of grains. In order to measure the effects of grain shape on mechanical properties of assembly of grains, three types of grains-high angular grains, medium angular grains and round grains are considered where several biaxial tests are conducted on assemblies with different grain types, The results show that the angularity of grains greatly affects the behavior of granular soil.

关键词： Discrete element method Granular soil Angularity Confining pressure

Rare Earth Elements Geochemistry of Sheikh-Marut Laterite Deposit,NW Mahabad,West-Azarbaidjan Province,Iran

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Acta Geologica Sinica(English Edition) 2013年第1期87卷 176-185页

作者： ali ABEDINI ali asghar CALAGARI Geology Department Faculty of SciencesUrmia University Geology Department Faculty of Natural SciencesUniversity of Tabriz

Laterite deposit at Sheikh-Marut （NW occurred within middle-upper Permian carbonate Mahabad, West-Azarbaidjan province, Iran） rocks. It consists of seven stratiform and/or discontinuous lenticular layers extending over 4.2 km in length and having thicknesses ranging from 3 to 14 m. Mineralogical data show that the ores contain kaolinite and hematite as major and boehmite, diaspore, halloysite, amesite, anatase, and muscovite-illite as minor mineral phases. The computed Ce anomaly values in the ores range from 0.05 to 20.84. Conservative index （e.g., Eu/Eu＊） suggests that this deposit is a product of alteration and weathering of basaltic rocks. Rhythmic increment of EREE values of the ores with approaching to the carbonate bedrocks shows an in-situ occurrence of lateritization processes. Mass change calculations of elements indicate that two competing processes namely leaching and fixation were the major regulating factors in concentration variation of REEs （La-Lu） in this deposit. The obtained results show that pH increase of weathering solutions by carbonate bedrocks, existence of organic matters, and the degree of comlexation with organic ligands played remarkable role in distribution of REEs during lateritization. Further geochemical considerations revealed that secondary phosphates, Mn-oxides and -hydroxides, diaspore, and anatase were the potential hosts for REEs in this deposit.

关键词： laterite geochemistry REEs Sheikh-Marut deposit Mahabad Iran

Survey on Video Security:Examining Threats,Challenges,and Future Trends

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Computers, Materials & Continua 2024年第9期80卷 3591-3635页

作者： ali asghar Amna Shifa Mamoona Naveed asghar Department of Artificial Intelligence Faculty of ComputingThe Islamia University of BahawalpurBahawalpur63100Pakistan School of Computer Science College of Science and EngineeringUniversity of GalwayGalwayH91 TK33Ireland

Videos represent the most prevailing form of digital media for communication,information dissemination,and ***,theirwidespread use has increased the risks of unauthorised access andmanipulation,posing significant *** response,various protection approaches have been developed to secure,authenticate,and ensure the integrity of digital *** study provides a comprehensive survey of the challenges associated with maintaining the confidentiality,integrity,and availability of video content,and examining how it can be *** then investigates current developments in the field of video security by exploring two critical research ***,it examine the techniques used by adversaries to compromise video data and evaluate their *** these attack methodologies is crucial for developing effective defense ***,it explores the various security approaches that can be employed to protect video data,enhancing its transparency,integrity,and *** compares the effectiveness of these approaches across different use cases,including surveillance,video on demand(VoD),and medical videos related to disease ***,it identifies potential research opportunities to enhance video data protection in response to the evolving threat *** this investigation,this study aims to contribute to the ongoing efforts in securing video data,providing insights that are vital for researchers,practitioners,and policymakers dedicated to enhancing the safety and reliability of video content in our digital world.

关键词： Attacks threats security services video manipulation video security

Numerical and experimental direct shear tests for coarse-grained soils

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Particuology 2009年第1期7卷 83-91页

作者： Ahad Bagherzadeh-Khalkhali ali asghar Mirghasemi School of Civil Engineering College of EngineeringUniversity of TehranTehranIran

The presence of particles larger than the permissible dimensions of conventional laboratory specimens causes difficulty in the determination of shear strength of coarse-grained soils. In this research, the influence of particle size on shear strength of coarse-grained soils was investigated by resorting to experimental tests in different scale and numerical simulations based on discrete element method （DEM）. Experimental tests on such soil specimens were based on using the techniques designated as ＂parallel＂ and ＂scalping＂ to prepare gradation of samples in view of the limitation of laboratory specimen size. As a second approach, the direct shear test was numerically simulated on assemblies of elliptical particles. The behaviors of samples under experimental and numerical tests are presented and compared, indicating that the modification of sample gradation has a significant influence on the mechanical properties of coarse-grained soils. It is noted that the shear strengths of samples produced by the scalping method are higher than samples by the parallel method. The scalping method for preparing specimens for direct shear test is therefore recommended. The micromechanical behavior of assemblies under direct shear test is also discussed and the effects of stress level on sample behavior are investigated.

关键词： Discrete element method Direct shear test Micromechanics Coarse-grained soil Shear strength

Distinguishing and Correlating Multiple Phases of Metamorphism across Multiply Deformed Regions Using the Axes of Inclusion Trails in Porphyroblasts

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Acta Geologica Sinica(English Edition) 2011年第4期85卷 784-791页

作者： Ahmad Afroz SHAH asghar ali School of Earth and Environmental Sciences James Cook UniversityTownsvilleQld 4811Australia

Successions of FIAs（foliation inflection/intersection axes preserved within porphyroblasts） provide a relative time scale for deformation and ***-situ dating of monazite grains preserved as inclusions within garnet and staurolite porphyroblasts within the foliations defining each FIA from such successions provides a rigorous approach to grouping ages that formed over extended periods of deformation and *** age and FIA progressions confirms the suitability of this approach plus provides access to lengthy histories that cannot otherwise be *** in the Big Thompson region of the Colorado Rocky Mountains,USA began about a SW-NE trending axis defined by FIA set 1 at around 1761±13 *** periods of tectonism occurred around 1712±25 and 1672±21 Ma about W-E and NW-SE trending FIAs 2 and 3, *** in the Balcooma Metamorphic Group NW of Greenvale in NE Queensland, Australia began around 470 Ma with the growth of garnet porphyroblasts about a W-E trending axis defined by FIA set *** monazite grains were preserved as inclusions in this mineral phase but they were in subsequently grown *** then occurred around 443.2±3.8,424±4 and 408.9±8.9 Ma about NNW-SSE,SSW-NNE and W-E trending FIAs 2,3 and 4,*** test of a FIA based approach to monazite dating in tectonic regimes in different parts of the world and with dramatically different ages suggests it can be used in all orogens containing porphyroblasts preserving inclusion trails.

关键词： FIAs porphyroblast monazite Colorado Balcooma Metamorphic Group

Simple separation method of Zn(Ⅱ) and Cd(Ⅱ) from brine solution of zinc plant residue and synthetic chloride media using solvent extraction

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Chinese Journal of Chemical Engineering 2020年第4期28卷 1055-1061页

作者： ali asghar Balesini Aghdam Hossein Yoozbashizadeh Javad Moghaddam Department of Materials Engineering Science and Research BranchIslamic Azad UniversityTehranIran Materials and Metallurgical Engineering Department University of ZanjanZanjanIran

In this work,the possibility of separation of Zn^2+and Cd^2+metal ions from chloride(brine)solutions was *** this purpose,simple solvent extraction(SX)experiments by di-2-ethylhexyl phosphoric acid(D2EHPA)in kerosene as a diluent was performed on synthetic and industrial chloride solution obtained from brine leaching of zinc filter cakes(by-product of zinc hydrometallurgical processing).The optimal conditions for separation were *** zinc extraction efficiency was 99%with negligible co-extraction of ***,a highΔpH0.5 value for Zn(Ⅱ)and Cd(Ⅱ)was ***-IR and slope analysis indicated that ZnClA·3HA and CdClA·3HA species were probably extracted.

关键词： Solvent extraction Brine media Leaching filter cakes Zinc Cadmium