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Role of Air Staging in a Batch-Type Fixed Bed Biomass Combustor under Constant Primary Air

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Journal of Thermal Science 2024年第1期33卷 284-299页

作者： Awais JUNEJO yasir M.AL-ABDELI Jacobo PORTEIRO School of Engineering Edith Cowan UniversityJoondalupWA 6027Australia CINTECX Universidade de Vigo Grupo de Tecnoloxia Enerxetica(GTE)36310 VigoEspana

Staged combustion of biomass is the most suitable thermo-chemical conversion for achieving lower gaseous emissions and higher fuel conversion *** a staged fixed bed combustion of biomass,combustion air is supplied in two *** the first stage,primary air is provided below the fuel,whereas in the later stage,secondary air is supplied in the freeboard *** available literature on the effects of air staging(secondary air location) at a constant primary air flow rate on combustion characteristics in a batch-type fixed bed combustor is limited and hence warrants further *** study resolves the effect of air staging,by varying the location of secondary air in the freeboard at five secondary to total air ratios in a batch-type fixed bed *** are reported for the effects of these controlled parameters on fuel conversion rate,overall gaseous emissions(CO_(2),CO and NO_x) and temperature *** fuel used throughout was densified hardwood *** show that a primary freeboard length(distance between fuel bed top and secondary air injection) of200 mm has higher fuel conversion rates and temperatures as well as lower CO emissions,at a secondary to total air ratio of 0.75 as compared to primary freeboard length of 300 ***,NO_x emissions were found to be lower for a primary freeboard length of 300 mm as compared to 200 *** increase in secondary to total air ratio from 0.33 to 0.75 resulted in higher freeboard temperatures and lower CO as well as NO_x *** outcomes of this study will be helpful in the effective design of commercial scale biomass combustors for more efficient and environmentally friendly combustion.

关键词： fixed bed combustor biomass combustion air staging freeboard temperature burning rate gaseous emissions

Temperature Uniformity,Correlations and the Flow Field in Swirling Impinging Jets

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Journal of Thermal Science 2023年第2期32卷 662-679页

作者： Zahir U.AHMED yasir M.AL-ABDELI Department of Mechanical Engineering Khulna University of Engineering&TechnologyKhulna 9203Bangladesh School of Engineering Edith Cowan UniversityJoondalupWA 6027Australia

Infrared thermography,velocity and impingement pressure measurements alongside numerical modelling are used in this study to resolve(heated)surface temperature distributions of turbulent swirling impinging jets for two Reynolds numbers(Re=11600 and 24600).Whilst building upon earlier discoveries for this same geometry,this paper provides three new contributions:(1)identifying the role of impingement distance(H/D)as a deciding factor in the trade-off between more efficient heat transfer(at high swirl numbers)and achieving better substrate temperature uniformity(lower gradients),(2)developing correlations to predict Nusselt number for swirling and non-swirling cooling jets,and(3)predicting the underlying mixing field in these jets and its interplay with the thermal distributions *** indicate substrate temperature uniformity varies based on H/D and swirl intensity(S)with a significant level of thermal non-uniformity occurring in near-field impingement(H/D=1)at stronger swirl(S=0.59 and 0.74).Four correlations describing the effects of S,Re,and H on the average heat transfer and stagnation heat transfer are developed and yield accuracies of 8%and 12%,*** recirculation near the impingement surface is predicted at H/D=1 for stronger swirl jets which disappears at other substrate *** peak wall shear stress reduces and the flow impingement becomes radially wider at higher H/D and *** turbulence or eddy viscosity regions for non-swirling jets(S=0)are predicted in the shear layer and entrainment regions at H/D=1,but such turbulence is confined to the impingement and wall jet regions for strongly swirling flows.

关键词： Temperature uniformity Nusselt number IR imaging CTA RANS

Advancements in Numerical Solutions:Fractal Runge-Kutta Approach to Model Time-Dependent MHD Newtonian Fluid with Rescaled Viscosity on Riga Plate

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Computer Modeling in Engineering & Sciences 2024年第11期141卷 1213-1241页

作者： Muhammad Shoaib Arif Kamaleldin Abodayeh yasir Nawaz Department of Mathematics and Sciences College of Humanities and SciencesPrince Sultan UniversityRiyadh11586Saudi Arabia Department of Mathematics Air UniversityPAF Complex E-9Islamabad44000Pakistan

Fractal time-dependent issues in fluid dynamics provide a distinct difficulty in numerical analysis due to their complex characteristics,necessitating specialized computing techniques for precise and economical *** study presents an innovative computational approach to tackle these *** main focus is applying the Fractal Runge-Kutta Method to model the time-dependent magnetohydrodynamic(MHD)Newtonian fluid with rescaled viscosity flow on Riga *** efficient computational scheme is proposed for handling fractal time-dependent problems in flow *** scheme is comprised of three stages and constructed using three different time *** stability of the scheme is shown by employing the Fourier series analysis to solve scalar *** scheme’s convergence is guaranteed for a time fractal partial differential equations *** scheme is applied to the dimensionless fractal heat and mass transfer model of incompressible,unsteady,laminar,Newtonian fluid with rescaled viscosity flow over the flat and oscillatory Riga plates under the effects of space-and temperature-dependent heat *** first-order back differences discretize the continuity *** results show that skin friction local Nusselt number declines by raising the coefficient of the temperature-dependent term of heat source and Eckert *** numerical simulations provide valuable insights into fluid dynamics,explicitly highlighting the influence of the temperature-dependent coefficient of the heat source and the Eckert number on skin friction and local Nusselt number.

关键词： Fractal scheme stability convergence fractal Newtonian fluid with rescaled viscosity fluid heat generation

A Hybrid SIR-Fuzzy Model for Epidemic Dynamics:A Numerical Study

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 3417-3434页

This study focuses on the urgent requirement for improved accuracy in diseasemodeling by introducing a newcomputational framework called the Hybrid SIR-Fuzzy *** integrating the traditional Susceptible-Infectious-Recovered(SIR)modelwith fuzzy logic,ourmethod effectively addresses the complex nature of epidemic dynamics by accurately accounting for uncertainties and imprecisions in both data and model *** main aim of this research is to provide a model for disease transmission using fuzzy theory,which can successfully address uncertainty in mathematical *** main emphasis is on the imprecise transmission rate parameter,utilizing a three-part description of its membership *** enhances the representation of disease processes with greater complexity and tackles the difficulties related to quantifying uncertainty in mathematical *** investigate equilibrium points for three separate scenarios and perform a comprehensive sensitivity analysis,providing insight into the complex correlation betweenmodel parameters and epidemic *** order to facilitate a quantitative analysis of the fuzzy model,we propose the implementation of a resilient numerical *** convergence study of the scheme demonstrates its trustworthiness,providing a conditionally positive solution,which represents a significant improvement compared to current forward Euler *** numerical findings demonstrate themodel’s effectiveness in accurately representing the dynamics of disease ***,when the mortality coefficient rises,both the susceptible and infected populations decrease,highlighting the model’s sensitivity to important epidemiological ***,there is a direct relationship between higher Holling type rate values and a decrease in the number of individuals who are infected,as well as an increase in the number of susceptible *** correlation offers a significant understanding of how many elements affect the con

关键词： Fuzzy-based model sensitivity equilibriumpoints proposed numerical scheme convergence and stability analysis

Experimental and numerical investigations of interface properties of Ti6Al4V/CP-Ti/Copper composite plate prepared by explosive welding

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Defence Technology（防务技术） 2021年第5期17卷 1592-1601页

作者： yasir Mahmood Peng-wan Chen I.A.Bataev Xin Gao State Key Lab of Explosion Science and Technology Beijing Institute of Technology100081PR China Novosibirsk State Technical University K.Marks 20630073NovosibirskRussia

Explosive welding technique is widely used in many *** technique is useful to weld different kinds of metal alloys that are not easily welded by any other welding *** plays an important role to improve the welding quality and control energy loss during the collision *** this paper,the Ti6Al4V plate was welded with a copper plate in the presence of a commercially pure titanium *** details of welded composite plate were observed through optical and scanning electron ***-base plate interface morphology showed a wavy structure with solid melted regions inside the ***,the energy dispersive spectroscopy analysis in the interlayer-base interface reveals that there are some identified regions of different kinds of chemical equilibrium phases of CueTi,***,Cu_(2)Ti,CuTi_(2),Cu_(4)Ti,*** study the mechanical properties of composite plates,mechanical tests were conducted,including the tensile test,bending test,shear test and Vickers hardness *** simulation of explosive welding process was performed with coupled Smooth Particle Hydrodynamic method,Euler and Arbitrary Lagrangian-Eulerian *** multi-physics process of explosive welding,including detonation,jetting and interface morphology,was observed with ***,simulated plastic strain,temperature and pressure profiles were analysed to understand the welding *** results show that the interlayer base plate interface was created due to the high plastic deformation and localized melting of the parent *** the collision point,both alloys behave like fluids,resulting in the formation of a wavy morphology with vortices,which is in good agreement with the experimental results.

关键词： Explosive welding Ti6Al4V/CP-Ti/Cu Smooth particle hydrodynamic(SPH) Microstructure Mechanical properties

Spatial variance and assessment of nitrogen dioxide pollution in major cities of Pakistan along N5-Highway

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Journal of Environmental Sciences 2016年第5期28卷 4-14页

作者： yasir Shabbir Muhammad Fahim Khokhar Reza Shaiganfar Thomas Wagner Institute of Environmental Sciences and Engineering (IESE) National University of Sciences and Technology (NUST)Islamabad Pakistan Satellite Remote Sensing Group Max-Planck-Institute for Chemistry

This paper discusses the findings of the first car MAX-DOAS（multi-axis differential optical absorption spectroscopy） field campaign（300 km long） along the National Highway-05（N5-Highway） of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide（NO_2）columns and corresponding concentrations along the N5-Highway from Islamabad to *** identification of NO_2 revealed that the concentrations were higher within major cities along the highway. The highest NO_2 vertical column densities（NO_2VCDs） were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO_2 VCDs measured by the ozone monitoring instrument（OMI） and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO_2 columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO_2 VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas.

关键词： Car MAX-DOAS Satellite remote sensing Nitrogen dioxide N5-Highway Pakistan National Environmental Quality Standards

3D Instance Segmentation Using Deep Learning on RGB-D Indoor Data

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Computers, Materials & Continua 2022年第9期72卷 5777-5791页

作者： Siddiqui Muhammad yasir Amin Muhammad Sadiq Hyunsik Ahn Department of Robot System Engineering Tongmyong UniversityBusan48520Korea Department of Information&Technology University of Central PunjabLahorePakistan Department of Electronics Engineering Tongmyong UniversityBusan48520Korea

3D object recognition is a challenging task for intelligent and robot systems in industrial and home indoor *** is critical for such systems to recognize and segment the 3D object instances that they encounter on a frequent *** computer vision,graphics,and machine learning fields have all given it a lot of ***,3D segmentation was done with hand-crafted features and designed approaches that didn’t achieve acceptable performance and couldn’t be generalized to large-scale *** learning approaches have lately become the preferred method for 3D segmentation challenges by their great success in 2D computer ***,the task of instance segmentation is currently less *** this paper,we propose a novel approach for efficient 3D instance segmentation using red green blue and depth(RGB-D)data based on deep *** 2D region based convolutional neural networks(Mask R-CNN)deep learning model with point based rending module is adapted to integrate with depth information to recognize and segment 3D instances of *** order to generate 3D point cloud coordinates(x,y,z),segmented 2D pixels(u,v)of recognized object regions in the RGB image are merged into(u,v)points of the depth ***,we conducted an experiment and analysis to compare our proposed method from various points of view and *** experimentation shows the proposed 3D object recognition and instance segmentation are sufficiently beneficial to support object handling in robotic and intelligent systems.

关键词： Instance segmentation 3D object segmentation deep learning point cloud coordinates

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 *** this study,we investigate thermal geometries and Hawking evaporation of the recently proposed topological dyonic dilaton BH in anti-de Sitter(Ad S)*** 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 ***,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 ***,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

Integral Transform Method for a Porous Slider with Magnetic Field and Velocity Slip

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Computer Modeling in Engineering & Sciences 2020年第3期122卷 1099-1118页

作者： Naeem Faraz yasir Khan Amna Anjum Anwar Hussain International Cultural Exchange School(ICES) Donghua UniversityShanghaiChina. Department of Mathematics University of Hafr Al-BatinHafar Al-BatinSaudi Arabia. DBS&HCEME National University of Science and TechnologyIslamabadPakistan.

Current research is about the injection of a viscous fluid in the presence of a transverse uniform magnetic field to reduce the sliding *** is a slip-on both the slider and the ground in the two cases,for example,a long porous slider and a circular porous *** utilizing similarity transformation Navier-Stokes equations are converted into coupled equations which are tackled by Integral Transform *** are obtained for different values of Reynolds numbers,velocity slip,and magnetic *** found that surface slip and Reynolds number has a substantial influence on the lift and drag of long and circular sliders,whereas the magnetic effect is also noticeable.

关键词： Porous slider MHD flow Reynolds number velocity slip integral transform method.