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Gravity-driven powder flow and the influence of external vibration on flow characteristics

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Particuology 2024年第5期88卷 201-209页

作者： Muhammad shahid Ansari Ratna Kumar Annabattula Sathyan Subbiah Department of Mechanical Engineering Indian Institute of Technology MadrasChennai 600036India

The controlled and homogeneous flow of dry granular powders through hoppers is essential for applications,namely,packaging of food grains,fertilizers and additive manufacturing processes such as directed energy deposition for better product quality.One of the major issues encountered in the granular flows through hoppers is flow stagnation due to the well-known arching phenomenon.Vibration-assisted granular flow through hoppers is one of the mechanisms used for better mass flow control.In this work,the influence of external mechanical vibration on the powder flow is investigated experimentally and using discrete element simulations.First,the mass flow rate through the hopper increases with an increase in vibration amplitude and then decreases,signifying the existence of an optimal amplitude of vibration.The DEM simulations explained the underlying mechanisms for the existence of an optimal amplitude of vibration corresponding to the maximum mass flow rate.A range of vibration amplitudes from 0 mm to 3.5 mm is used to study the flow behaviour;the maximum flow of around 33 g/s to 35 g/s is observed for 0.75 mm to 1.25 mm vibration amplitude for the hopper-particle combination studied in this work.The work also reports the influence of vibration frequency,hopper,and particle dimension on the flow characteristics.The research facilitates the effective use of mechanical vibration to enhance powder flow that can further be extended to non-spherical and multi-material particles.

关键词： Discrete element method Flow rate Granular flow Path tracking Vibration intensity

Consequences of Rényi entropy on the thermal geometries and Hawking evaporation of topological dyonic dilaton black hole

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Communications in Theoretical Physics 2024年第2期76卷 102-110页

作者： Muhammad Yasir Xia Tiecheng Muhammad Usman shahid Chaudhary Department of Mathematics Shanghai University and Newtouch Center for Mathematics of Shanghai UniversityShanghai200444China Department of Natural Sciences and Humanities University of Engineering and Technology LahoreNew CampusPakistan

The thermodynamics of black holes(BHs)has had a profound impact on theoretical physics,providing insight into the nature of gravity,the quantum structure of spacetime and the fundamental laws governing the Universe.In this study,we investigate thermal geometries and Hawking evaporation of the recently proposed topological dyonic dilaton BH in anti-de Sitter(Ad S)space.We consider Rényi entropy and obtain the relations for pressure,heat capacity and Gibbs free energy and observe that the Rényi parameter and dilaton field play a vital role in the phase transition and stability of the BH.Moreover,we use Weinhold,Ruppeiner and Hendi Panahiyah Eslam Momennia models to evaluate the scalar curvature of the BH and find out that the divergence points of the scalar curvature coincides with the zero of specific heat.Finally,using Stefan–Boltzmann law,we determine that the BH without a dilaton field evaporates far more quickly compared to the dilaton BH in Ad S space.

关键词： topological dyonic dilaton black hole phase transition thermal geometry Hawking evaporation

Weathering and accumulation of trace elements in the soils of the Porali Plain, Balochistan: repercussions in agriculture

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Acta Geochimica 2024年第2期43卷 214-234页

作者： Maria Kaleem Erum Bashir shahid Naseem Tahir Rafique Bushra Shahab Department of Geology University of KarachiKarachi 75270Pakistan Applied Chemistry Research Centre PCSIR Laboratories ComplexKarachi 75280Pakistan

This study is theﬁrst attempt to assess the nature of the soil,especially on the western side of the Porali Plain in Balochistan;a new emerging agriculture hub,using weathering and pollution indices supplemented by multi-variate analysis based on geochemical data.The outcomes of this study are expected to help farmers in soil manage-ment and selecting suitable crops for the region.Twenty-ﬁve soil samples were collected,mainly from the arable land of the Porali Plain.After drying and coning-quarter-ing,soil samples were analyzed for major and trace ele-ments using the XRF technique;sieving and hydrometric methods were employed for granulometric analysis.Esti-mated data were analyzed using Excel,SPSS,and Surfer software to calculate various indices,correlation matrix,and spatial distribution.The granulometric analysis showed that 76%of the samples belonged to loam types of soil,12%to sand type,and 8%to silt type.Weathering indices:CIA,CIW,PIA,PWI,WIP,CIX,and ICV were calculated to infer the level of alteration.These indices reﬂect mod-erate to intense weathering;supported by K_(2)O/AI_(2)O_(3),Rb/K_(2)O,Rb/Ti,and Rb/Sr ratios.Assessment of the geo-ac-cumulation and Nemerow Pollution indices pinpoint rela-tively high concentrations of Pb,Ni,and Cr concentration in the soils.The correlation matrix and Principal Compo-nent Analysis show that the soil in this study area is mainly derived from the weathering of igneous rocks of Bela Ophiolite(Cretaceous age)and Jurassic sedimentary rocks of Mor Range having SEDEX/MVT type mineralization.Weathering may result in the undesirable accumulation of certain trace elements which adversely affects crops.

关键词： Weathering indices Pollution indices Accumulation Repercussions Trace elements Multivariate analyses Porali Plain Balochistan

Experimental Study on Heat Storage Properties Comparison of Paraffin/Metal Foams Phase Change Material Composites

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Journal of Thermal Science 2024年第2期33卷 469-478页

作者： Waqar AHMED Abid HUSSAIN Hanzla shahid Imran ALI Hafiz Muhammad ALI Department of Mechanical Engineering University of Engineering and TechnologyTaxila47080Pakistan Department of Mechanical Engineering Institute of Space TechnologyIslamabadPakistan Department of Mechanical Mechatronics and Manufacturing EngineeringUniversity of Engineering and Technology LahoreFaisalabad CampusPunjabPakistan Mechanical Engineering Department King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Renewable Energy and Power Systems(IRC-REPS) King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia

Heat storage properties of phase change materials(PCMs) are essential characteristics that perform a key role in thermal heat energy storage systems.The thermal properties of PCMs can be improved by developing metal foam/PCM composites.The addition of metal foam in PCMs has a significant effect on the thermal characteristics of PCMs.In this paper,the heat storage properties of two different metal foam/PCM composites were experimentally examined.The behavior of paraffin in metal foam(copper and iron-nickel)/paraffin composites concerning pure paraffin at a constant heat flux of 1000 W/m^(2) in three directions simultaneously(x,y,and z) was studied.Paraffin was infiltrated into copper and iron-nickel foams to develop composite materials which resulted in enhancing the thermal conductivity of the paraffin.A comparative analysis is made on the heat storage properties of paraffin in copper and iron-nickel foams/paraffin composites.Inner temperature distribution during the phase transition process is experimentally evaluated.This comparison indicates that temperature uniformity in copper foam/paraffin composite is better than in iron-nickel foam/paraffin composite and pure paraffin at the same heat flux.Experimental results show that at heat flux of 1000 W/m^(2),the heat storage time for copper foam/paraffin composite is 20.63% of that of iron-nickel foam/paraffin composite.

关键词： heat storage capacity paraffin/metal foam composite temperature uniformity heat storage rate phase transition process

Interactive map reports summarizing bivariate geographic data

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Visual Informatics 2019年第1期3卷 27-37页

作者： shahid latif Fabian Beck University of Duisburg–Essen paluno–The Ruhr Institute of Software TechnologyGermany

Bivariate map visualizations use different encodings to visualize two variables but comparison across multiple encodings is challenging.Compared to a univariate visualization,it is significantly harder to read regional differences and spot geographical outliers.Especially targeting inexperienced users of visualizations,we advocate the use of natural language text for augmenting map visualizations and understanding the relationship between two geo-statistical variables.We propose an approach that selects interesting findings from data analysis,generates a respective text and visualization,and integrates both into a single document.The generated reports interactively link the visualization with the textual narrative.Users can get additional explanations and have the ability to compare different regions.The text generation process is flexible and adapts to various geographical and contextual settings based on small sets of parameters.We showcase this flexibility through a number of application examples.

关键词： Geographic visualization Natural language generation Interactive documents

Bivariate joint distribution analysis of the flood characteristics under semiparametric copula distribution framework for the Kelantan River basin in Malaysia

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Journal of Ocean Engineering and Science 2021年第2期6卷 128-145页

作者： shahid latif Firuza Mustafa Department of Geography University of MalayaKuala Lumpur 50603Malaysia

Flood is becoming the severe hydrologic issue at the Kelantan River basin in Malaysia.The joint distribution analysis amongst multiple interacting flood characteristics,i.e.,flood peak discharge flow,volume,and duration series usually provide a comprehensive understanding of the hydrologic risk assessments through visualizing the multivariate exceedance probability or return periods.The traditional copulas-based methodology is frequently employed under parametric settings where parametric family functions are often employed to model univari-ate marginal distribution before capturing their dependence structure.Actually,no universal rules and literature are imposed to model any flood vectors through any fixed or predefined density function,which would follow the different distribution and needs to model by fitting most parsimonious function.Also,the copula function already relaxes the restriction of selecting marginal distributions from the same distribution families.Therefore,incorporation of non-parametric kernel density estimations or KDE would be much stable and less biased smoothing alternatives than the parametric approach.In this literature,the semi-parametric copula-based methodology is incorporated,where the flood marginals are modelled under the kernel functions and applied as a case study for 50 years annual maximum(AM)flood samples of the Kelantan River basin at the Gulliemard Bridge gauge station in Malaysia.The Archimedean families copulas(i.e.,Frank,Gumbel and Clayton)and Elliptical copula(i.e.,Gaussian copula)are tested,and thus best-fitted copulas are employed to model the bivariate joint distribution amongst flood characteristics,and which further employed to derive joint and conditional return periods.

关键词： Flood Kelantan River basin Semiparametric Copulas framework Nonparametric marginal distribution Kernel density estimation Return periods

Metabolic dysfunction-associated steatotic liver disease heterogeneity: Need of subtyping

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World Journal of Gastrointestinal Pathophysiology 2024年第2期15卷 1-14页

作者： shahid Habib Department of Hepatology Liver Institute PLLCTucsonAZ 85716United States

Metabolic dysfunction-associated steatotic liver disease(MASLD)is a widespread global disease with significant health burden.Unhealthy lifestyle,obesity,diabetes mellitus(DM),insulin resistance,and genetics have been implicated in the pathogenesis of MASLD.A significant degree of heterogeneity exists among each of above-mentioned risk factors.Heterogeneity of these risk factors translates into the heterogeneity of MASLD.On the other hand,MASLD can itself lead to insulin resistance and DM.Such heterogeneity makes it difficult to assess the natural course of an individual with MASLD in clinical practice.At present MASLD is considered as one disease despite the variability of etiopathogenic processes,and we lack the consensus definitions of unique subtypes of MASLD.In this review,pathogenic processes of MASLD are discussed and a need of subtyping is recommended.

关键词： Metabolic dysfunctions-associated steatotic liver disease Visceral obesity Genetics Diabetes Insulin resistance

Rational manipulation of electrolyte to induce homogeneous SEI on hard carbon anode for sodium-ion battery

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Journal of Energy Chemistry 2024年第7期94卷 414-429页

作者： Lu Liu Lingling Xiao Zhi Sun shahid Bashir Ramesh Kasi Yonghong Gu Ramesh Subramaniam Research Center for Clean Utilization Technology Phosphorous Resources Hubei Three Gorges PolytechnicYichang 443000HubeiChina Department of Physics Faculty of ScienceUniversiti MalayaKuala Lumpur 50603Malaysia UM Power Energy Dedicated Advanced Centre(UMPEDAC) Level 4Wisma R&DUniversiti MalayaKuala Lumpur 59990Malaysia Department of Chemistry Saveetha School of EngineeringInstitute of Medical and Technical ScienceSaveetha UniversityChennai 602105TamilnaduIndia

Sodium-ion batteries(SIBs)have great potential to be the next major energy storage devices due to their obvious advantages and developing advanced electrodes and electrolytes is urgently necessary to pro-mote its future industrialization.However,hard carbon as a state-of-the-art anode of SiBs still suffers from the low initial Coulomb efficiency and unsatisfactory rate capability,which could be improved by forming desirable solid electrolyte interphases(SEI)to some extent.Indeed,the chemistry and morphol-ogy of these interfacial layers are fundamental parameters affecting the overall battery operation,and optimizing the electrolyte to dictate the quality of SEI on hard carbon is a key strategy.Hence,this review summarizes the recent research on SEI design by electrolyte manipulation from solvents,salts,and addi-tives.It also presents some potential mechanisms of sEI formation in various electrolyte systems.Besides,the current advanced characterization techniques for electrolyte and SEl structure analyses have been comprehensively discussed.Lastly,current challenges and future perspectives of sEl formation on hard carbon anode for SIBs are provided from the viewpoints of its compositions,evolution processes,struc-tures,and characterization techniques,which will promote SEl efficient manipulation and improve the performance of hard carbon,and further contribute to the development of SIBs.

关键词： SEI Electrolyte optimization Hard carbon Electrochemical performance Sodium-ion batteries

Barley chitinase genes expression revamp resistance against whitefly (Bemisia Tabaci) in transgenic cotton (Gossypium hirsutum L.)

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Journal of Cotton Research 2024年第1期7卷 90-100页

作者： BASHIR Samina YAQOOB Amina BASHIR Rohina BUKHARI Shanila shahid Naila AZAM Saira BAKHSH Allah HUSNAIN Tayyab shahid Ahmad Ali RAO Abdul Qayyum Centre of Excellence in Molecular Biology University of the PunjabLahore 53700Pakistan Department of Botany Kinnaird College for Women UniversityLahore 54000Pakistan Department of Botany Government College UniversityFaisalabad 38000Pakistan Institute of Botany University of the PunjabLahore 54590Pakistan.

Background Chitinase is an enzyme that hydrolyzes chitin,a major component of the exoskeleton of insects,including plant pests like whiteflies.The present study aimed to investigate the expression of chemically synthesized barley ch1 and chi2 genes in cotton(Gossypium hirsutum)through Agrobacterium-mediated transformation.Fifty-five putative transgenic cotton plants were obtained,out of which fifteen plants successfully survived and were shifted to the field.Using gene-specific primers,amplification of 447 bp and 401 bp fragments confirmed the presence of the ch1 and chi2 genes in five transgenic cotton plants of the T0 generation.These five plants were further evalu-ated for their mRNA expression levels.The T0 transgenic cotton plants with the highest mRNA expression level and better yield performance in field,were selected to raise their subsequent progenies.Results The T1 cotton plants showed the highest mRNA expression levels of 3.5-fold in P10(2)for the ch1 gene and 3.7-fold in P2(1)for the chi2 gene.Fluorescent in situ hybridization(FISH)confirmed a single copy number of ch1 and chi2(hemizygous)on chromosome no.6.Furthermore,the efficacy of transgenes on whitefly was evaluated through an insect bioassay,where after 96 h of infestation,mortality rates of whitefly were calculated to be 78%–80%in transgenic cotton plants.The number of eggs on transgenic cotton plants were calculated to be 0.1%–0.12 per plant compared with the non-transgenic plants where egg number was calculated to be 0.90–1.00 per plant.Conclusion Based on these findings,it can be concluded that the chemically synthesized barley chitinase genes(ch1 and chi2)have the potential to be effective against insects with chitin exoskeletons,including whiteflies.The transgenic cotton plants expressing these genes showed increased resistance to whiteflies,resulting in reduced egg numbers and higher mortality rates.

关键词： Chitinase Cotton White fly Transgene Bioassay