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Spline R-Function and Applications in FEM

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Numerical Mathematics(Theory,Methods and Applications) 2020年第1期13卷 150-175页

作者： Tianhui Yang ammar Qarariyah Jiansong Deng School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026AnhuiChina

R-function is a widely used tool when considering objects obtained through the Boolean operations start from simple base ***,there is square root operation in the *** that the use of splines will facilitate the calculations within the CAD system,in this paper,we propose a system of R-functions represented in spline form called Spline R-function(SR).After trans-forming the function ranges of two base primitives to a new coordinate system,a series of sign constraints following a specific Boolean operation are derived and the spline R-function can be formulated as a piecewise *** of SR in both B´ezier form and B-spline form have been *** which the B´ezier ordinates are determined with the help of the B-net method through setting up a series of relations according to the sign constraints and properties of *** construction processes for both Boolean intersection and union operations with different smoothness are discussed in *** experiments are conducted to show the potential of the proposed spline R-function.

关键词： R-functions CSG Boolean operations B-splines B-net method WEB method

Comprehensive evaluation and sensitivity analysis of regeneration energy for acid gas removal plant using single and activated-methyl diethanolamine solvents

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Chinese Journal of Chemical Engineering 2020年第6期28卷 1684-1693页

作者： ammar Ali Abd Samah Zaki Naji Ahmed Barifcani Water Resources Engineering College Al-Qasim Green UniversityBabylonIraq Petroleum Engineering Department Kerbala UniversityKerbalaIraq Chemical Engineering Department Curtin University of TechnologyPerthAustralia.

The absorption of acid gas using reactive amines is among the most widely used types of capturing ***,the absorption process requires intensive energy expenditure majorly in the solvent regeneration *** study simultaneously evaluated the regeneration energy of MDEA and PZ/MDEA solvents in terms of heat of absorption,sensible heat,and vaporization *** Hysys version 8.8 simulation tool is applied to model the full acid gas removal plant for the chemical absorption *** new energy balance technique presents around the absorption and desorption columns to bring a new perspective of energy distribution in the capturing of acid gas *** analysis of regeneration energy and its three contributors is performed at several operation parameters such as absorber and stripper pressures,lean amine circulation rate,solvent concentration,reflux ratio,and CO2 and H2 S *** results show that the heat of absorption of PZ/MDEA system is higher than that for MDEA system for the same operating *** sensible heat is the main contributor in the required regeneration energy of MDEA solvent *** simulation results have been validated against data taken from real plant and *** product specifications of our simulation corroborate with real plant data in an excellent approach;additionally,the profile temperature of the absorber and the stripper columns are in good agreement with *** overall results highlight the direction of the effects of each parameter on the heat of absorption,sensible heat,and vaporization heat.

关键词： Heat of absorption Sensible heat Vaporization heat Regeneration energy Acid gases capturing Piperazine Activated-Methyl diethanolamine

STABILITY OF THE S-LEFT AND S-RIGHT ESSENTIAL SPECTRA OF A LINEAR OPERATOR

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Acta Mathematica Scientia 2014年第6期34卷 1922-1934页

作者： Aymen ammar Bilel BOUKETTAYA Aref JERIBI Département de Mathématiques Faculté des Sciences de SfaxUniversité de SfaxRoute de Soukra Km 3.5B.P.11713000SfaxTunisie

In the present paper, we define the S-left and the S-right essential spectra of a linear operator and we study the stability of the S-essential spectra on a Banach space.

关键词： S-left essential spectra S-right essential spectra Fredholm perturbation Riesz operator

Epithelial-mesenchymal transition mediated tumourigenesis in the gastrointestinal tract

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World Journal of Gastroenterology 2008年第24期14卷 3792-3797页

作者： ammar Natalwala Robert Spychal Chris Tselepis The Medical School University of Birmingham Sandwell and West Birmingham Hopsitals NHS Trust CRUK Institute for Cancer Studies University of Birmingham

Epithelial-mesenchymal transition (EMT) is a highly conserved process that has been well characterised in embryogenesis. Studies have shown that the aberrant activation of EMT in adult epithelia can promote tumour metastasis by repressing cell adhesion molecules,including epithelial (E)-cadherin. Reduced intracellular adhesion may allow tumour cells to disseminate and spread throughout the body. A number of transcription proteins of the Snail superfamily have been implicated in EMT. These proteins have been shown to be over-expressed in advanced gastrointestinal (GI) tumours including oesophageal adenocarcinomas,colorectal carcinomas,gastric and pancreatic cancers,with a concomitant reduction in the expression of E-cadherin. Regulators of EMT may provide novel clinical targets to detect GI cancers early,so that cancers previously associated with a poor prognosis such as pancreatic cancer can be diagnosed before they become inoperable. Furthermore,pharmacological therapies designed to inhibit these proteins will aim to prevent local and distant tumour invasion.

关键词： Epithelial-mesenchymal transition Transcription proteins E-cadherin Gastrointestinalcancer

Shear reinforcement effect of reinforced concrete tie-columns on the lateral resistance of confined masonry walls

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Earthquake Engineering and Engineering Vibration 2016年第2期15卷 313-324页

作者： Samir Bouhedja Abdelkrim Bourzam Ahmed Boukhaled ammar Nechnech University of Sciences and Technology Houari Boumediene(USTHB)Faculty of Civil EngineeringLaboratory of EnvironmentWaterGeomechanics and Structures(LEEGO)BP 32 El AliaBab EzzouarAlgiers16111Algeria University of Sciences and Technology Houari Boumediene(USTHB)Faculty of Civil EngineeringLaboratory of Built Environment Research(LBE)BP 32 El AliaBab EzzouarAlgiers16111Algeria

Tie-columns improve significantly the lateral resistance of masonry bearing walls against persistent, transient and accidental loads. The research work described herein has been carried out to assess the lateral resistance of confined masonry walls, where contribution of the masonry panel is evaluated according to material mechanics and tie-columns effect is estimated by a proposed analytical formulation based on a model reported on previously. This approach takes into account the effect of dowel support on the reaction of its adjacent shear reinforcement： the conditions for the various contributions of transverse reinforcements are better defined following a clear evaluation of the participation ratio of these reinforcements. Lateral resistances of confined masonry walls measured in full-scale tests and gleaned from the literature are compared and checked with resistances calculated using the present approach.

关键词： reinforcement columns confined reinforced walls Shear formulation panel participation herein

Oilfield produced water treatment in internal-loop airlift reactor using electrocoagulation/flotation technique

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Chinese Journal of Chemical Engineering 2018年第4期26卷 879-885页

作者： Saad H.ammar Ahmed S.Akbar Department of Chemical engineering AL-Nahrain University

Oilfield produced water is large quantities of salty water trapped in underground formations and subsisted under high temperatures and pressures that are brought to the surface along with oil during production. Produced water(PW) contains a lot of pollutants such as hydrocarbons and metals, this water must be treated before disposal. Therefore, different techniques are being used to treat produced water. Electrocoagulation is an efficient treatment technique involving the dissolution of anodes and formation of electro-coagulants, while the simultaneous generation of H_2 bubbles at the cathode leads to the pollutant removal by flotation. Electrocoagulation(EC)method is one of the most promising and widely used processes to treat oilfield produced water. In the present work, a conventional internal-loop(draught tube) airlift reactor was utilized as electrocoagulation/flotation cell for PW treatment by inserting two aluminum electrodes in the riser section of the airlift reactor. The EC airlift reactor was operated in a batch mode for the liquid phase. Different experimental parameters were studied on the oil and turbidity removal efficiencies such as current density, initial pH, electrocoagulation time, and air *** experimental results showed that mixing of the oil droplets in the PW was accomplished using only the liquid recirculation resulted by H_2 microbubbles generated by EC process which enhanced the oil removal. The experimental results further showed that the EC time required achieving ≥ 90% oil removal efficiency decreases from 46 to 15 min when operating current density increases from 6.8 to 45.5 mA·cm^(-2). This reactor type was found to be highly efficient and less energy consuming compared to conventional existing electrochemical cells which used mechanical agitation.

关键词： Produced water Wastewater treatment Electrocoagulation/flotation Internal loop Airlift reactor

Entropy generation of MHD natural convection heat transfer in a heated incinerator using hybrid-nanoliquid

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Propulsion and Power Research 2021年第2期10卷 143-154页

作者： Bouchmel Mliki Mohamed ammar Abbassi Materials Energy and Renewable EnergiesFaculty of Sciences of GafsaB.P.19ZarrougGafsa2112Tunisia

The present study explores magnetic hybrid-nanoliquid(Al_(2)O_(3)-Cu/H_(2)O)natural convection in a heated incinerator shaped cavity by using the lattice Boltzmann method(LBM).Numerical results are presented in the form temperature contours,stream function and local entropy *** interaction between various physical phenomena characterizing this problem including the natural convection and the magnetic field has been *** of Rayleigh number(Ra=10^(3)-10^(6)),volumetric fraction of nanoparticles(ϕ=0-0.04),and Hartmann number(Ha=0-90)are clarified in details through graphical *** depict that the average Nusselt number(Nu_(m))and average entropy generation(S_(gen,A))increases with an increase of the Rayleigh number while are decreased by applying a magnetic *** addition,it is found that the average Nusselt number(Nu_(m))increases with the rise of volumetric fraction of nanoparticles for all Rayleigh and Hartmann ***,an opposite effect is obtained by an increase in volumetric fraction of nanoparticles on the average entropy generation(S_(gen,A)).Finally,the numerical results demonstrate that the effect of Lorentz force is reduced when the heat transfer regime conduction is considered.

关键词： Incinerator Entropy generation Natural convection Hybrid-nanoliquid Magnetohydrodynamic(MHD)

Fractional order extremum seeking approach for maximum power point tracking of photovoltaic panels

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Frontiers in Energy 2015年第1期9卷 43-53页

作者： ammar NECAIBIA Samir LADACI Abdelfatah CHAREF Jean Jacques LOISEAU Research Unit in Renewable Energies in the Saharan Medium CDEREPST URER-MS Adrar 01000 Algeria Department ofElectrical Engineering University of Skikda Skikda 21000 Algeria Department of Electronics Electrotechnics and Automatics NationalPolytechnic School of Constantine Constantine 25000 Algeria SP-LabLaboratory Department of Electronics University of Constantine 1Constantine 25000 Algeria SP-Lab Laboratory Department of Electronics University of Con-stantine 1 Constantine 25000 Algeria Research Institute in Communications and Cybernetics CNRS UMR6597 1 rue de la No~ 44321 Nantes France

Due to the high interest in renewable energy and diversity of research regarding photovoltaic （PV） array, a great research effort is focusing nowadays on solar power generation and its performance improvement under various weather conditions. In this paper, an integrated framework was proposed, which achieved both maximum power point tracking （MPPT） and minimum ripple signals. The proposed control scheme was based on extremum- seeking （ES） combined with fractional order systems （FOS）. This auto-tuning strategy was developed to maximize the PV panel output power through the regulation of the voltage input to the DC/DC converter in order to lead the PV system steady-state to a stable oscillation behavior around the maximum power point （MPP）. It is shown that fractional order operators can improve the plant dynamics with respect to time response and disturbance rejection. The effectiveness of the proposed controller scheme is illustrated with simulations using measured solar radiation data.

关键词： extremum seeking (ES) fractional ordercontrol (FOC) fractional calculus photovoltaic (PV)

Evaluation of the performance of demand control ventilation system for school buildings located in the hot climate of Saudi Arabia

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Building Simulation 2022年第6期15卷 1067-1082页

作者： Alaa Alaidroos Ayad Almaimani Moncef Krarti ammar Dahlan Rahif Maddah Architectural Engineering Department King Abdulaziz UniversityRabighSaudi Arabia Faculty of Architecture and Planning King Abdulaziz UniversityJeddahSaudi Arabia Building Systems Program University of Colorado BoulderBoulderCOUSA

The advantages of the demand control ventilation system(DCV)have been widely discussed in previous research ***,the literature has not addressed the benefits of DCV on controlling indoor CO_(2)concentration and minimizing cooling energy consumption for school buildings located in extremely hot ***,this paper contributes to the development of DCV and mechanical ventilation systems through a comprehensive evaluation of these systems to maintain acceptable indoor air quality(IAQ)while minimizing cooling energy demands for school buildings located in the harsh hot climate of Saudi *** evaluation is based on a calibrated whole-building energy model and validated IAQ predictions using field data obtained from a school case study in *** results of this research study confirm that hourly and sub-hourly monitoring of indoor CO_(2)concentration is required to ensure optimal design and operation of the ventilation systems in *** addition,the analyses indicate that a 13%increase in cooling energy end-use can result for any additional 0.1 students/m^(2)density increase in the ***,the energy penalties related to ventilation needs can be reduced by up to 25%using DCV instead of conventional mechanical ventilation systems for school buildings located in Saudi Arabia’s hot climate.

关键词： mechanical ventilation demand control ventilation(DCV) indoor air quality(IAQ) CO_(2)concentration energy efficiency school buildings