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EXISTENCE OF POSITIVE SOLUTIONS FOR A CLASS OF PARABOLIC EQUATIONS WITH NATURAL GROWTH TERMS AND L^1 DATA

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Acta Mathematica Scientia 2014年第4期34卷 1127-1144页

作者： kaouther AMMAR Hicham REDWANE Department of Mathematics Faculty of sciencesTaibah UniversityP.O. Box 344 Al MadinahSaudi Arabia Facult'e des Sciences Juridiques Economiques et SocialesUniversit'e Hassan 1B.P. 784SettatMorocco

We study a class of nonlinear parabolic equations of the type：δb（u）/δt-div（a（x,t,u）△u）＋y（u）｜△u｜^2=f,where the right hand side belongs to L^1（Q）, b is a strictly increasing C^1-function and -div（a（x, t, u）△u） is a Leray-Lions operator. The function g is just assumed to be continuous on R and to satisfy a sign condition. Without any additional growth assumption on u, we prove the existence of a renormalized solution.

关键词： renormalized solutions natural growth terms L^1 data

Does oil price affect the value of firms？ Evidence from Tunisian listed firms

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Frontiers in Energy 2016年第1期10卷 1-13页

作者： kaouther ZAABOUTI Ezzeddine BEN MOHAMED Abdelfettah BOURI Faculty of Economics and Management of Sfax University of SfaxMonastir 5046 Tunisia Department of Accounting College of Business & Economics QassimUniversity Buraidah 51431 Kingdom of Saudi Arabia

A new debate on the potential impact of oil price changes on the value of firms was initiated in this paper. Using a stochastic frontier approach, an attempt was made to derive the optimal value Q＊ of firms and calculate the Q value observed. Then the shortfall （Q＊-Q） which represents the inefficiency term was explained. Starting from 19 industrial Tunisian firms listed on the Tunis Stock Exchange between 2007 and 2011, the fact that variation of oil prices can largely explain distortions in the value of firms was empirically demonstrated.

关键词： oil price value of firm stochastic frontier approach industrial Tunisian firms

Stabilizing Sets of PI/PID Controllers for Unstable Second Order Delay System

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International Journal of Automation and computing 2014年第2期11卷 210-222页

作者： Rihem Farkh kaouther Laabidi Mekki Ksouri Laboratory for Analysis Conception and Control of SystemsLR-11-ES20Department of Electrical EngineeringNational Engineering School of TunisTunis El Manar University

In this paper, the problem of stabilizing an unstable second order delay system using classical proportional-integralderivative(PID) controller is considered. An extension of the Hermite-Biehler theorem, which is applicable to quasi-polynomials, is used to seek the set of complete stabilizing proportional-integral/proportional-integral-derivative(PI/PID) parameters. The range of admissible proportional gains is determined in closed form. For each proportional gain, the stabilizing set in the space of the integral and derivative gains is shown to be a triangle.

关键词： Hermite-Biehler theorem stability PI/PID controllers second order unstable delay system stability region.

Solid solution evolution during mechanical alloying in Cu–Nb–Al compounds

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International Journal of Minerals,Metallurgy and Materials 2019年第9期26卷 1129-1139页

作者： kaouther Zaara Mahmoud Chemingui Virgil Optasanu Mohamed Khitouni Laboratory of Inorganic Chemistry UR 11-ES-73University of SfaxB.P. 1171Sfax 3018Tunisia ICB UMR 6303 CNRSUniversity of Bourgogne Franche Comté9 av. Alain Savary21078 Dijon CedexFrance

This work concerns the structural evolution of Cu70Nb20Al10(at%) alloy processed by mechanical alloying using a planetary ball mill in air atmosphere for different times(4 to 200 h). The morphological, structural, microstructural, and thermal behaviors of the alloy were investigated by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and differential scanning calorimetry. X-ray diffraction patterns were examined using the Rietveld refinement technique with the help of the MAUD software. A disordered FCC-Cu(Nb,Al) solid solution was formed after 8 h of milling. The crystallite size, microstrain, and lattice parameter were determined by the Rietveld method. With increasing milling time, the crystallite size of the final product-ternary-phase FCC-Cu(Nb,Al)-is refined to the nanometer scale, reaching 12 nm after 200 h. This crystallographic structure combines good mechanical strength and good ductility. An increase in microstrain and partial oxidation were also observed with increasing milling time.

关键词： powder metallurgy mechanical alloying nanomaterials copper-based alloy solid solution

Time Series Facebook Prophet Model and Python for COVID-19 Outbreak Prediction

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Computers, Materials & Continua 2021年第6期67卷 3781-3793页

作者： Mashael Khayyat kaouther Laabidi Nada Almalki Maysoon Al-zahrani Department of Information Systems and Technology Collage of Computer Science and EngineeringUniversity of JeddahJeddah23218Saudi Arabia Department of Computer and Network Engineering Collage of Computer Science and EngineeringUniversity of JeddahJeddah23218Saudi Arabia and University of TunisElmanarTunisia

COVID-19 comes from a large family of viruses identied in 1965;to date,seven groups have been recorded which have been found to affect *** the healthcare industry,there is much evidence that Al or machine learning algorithms can provide effective models that solve problems in order to predict conrmed cases,recovered cases,and *** researchers and scientists in the eld of machine learning are also involved in solving this dilemma,seeking to understand the patterns and characteristics of virus attacks,so scientists may make the right decisions and take specic ***,many models have been considered to predict the Coronavirus outbreak,such as the retro prediction model,pandemic Kaplan’s model,and the neural forecasting *** research has used the time series-dependent face book prophet model for COVID-19 prediction in India’s various ***,we proposed a prediction and analysis model to predict COVID-19 in Saudi *** time series dependent face book prophet model is used to t the data and provide future *** study aimed to determine the pandemic prediction of COVID-19 in Saudi Arabia,using the Time Series Analysis to observe and predict the coronavirus pandemic’s spread daily or *** found that the proposed model has a low ability to forecast the recovered cases of the COVID-19 *** contrast,the proposed model of death cases has a high ability to forecast the COVID-19 ***,obtaining more data could empower the model for further validation.

关键词： COVID-19 time series analysis prediction face book prophet model python

Phytochemical analysis and biological activities of Hertia cheirifolia L. roots extracts

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Asian Pacific Journal of Tropical Medicine 2017年第12期10卷 1134-1139页

作者： kaouther Majouli Assia Hamdi Malek Besbes Hlila Laboratory of Biochemistry Research Unit:UR 12ES08 “Cell Signaling and Pathologies”Faculty of MedicineUniversity of MonastirTunisia Laboratory of Chemical Galenic and Pharmacological Development of DrugsFaculty of PharmacyUniversity of MonastirTunisia Laboratory of Transmissible Diseases and of Biologically Active Substances MDT01Faculty of PharmacyUniversity of MonastirTunisia

Objective: To test the antioxidant, antimicrobial and a-glucosidase inhibitory activities of the roots extracts from Hertia cheirifolia(H. cheirifolia) ***: Total phenolics and total flavonoids content of the different extracts were determined by colorimetric methods and reverse phase high-performance liquid chromatography(RP-HPLC) was performed to identify various chemical *** different extracts were evaluated for antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl(DPPH), 2,2-azino-bis-3-ethylenebenzothiozoline-6-sulfonic acid(ABTS·^+) and β-carotene bleaching tests and α-glucosidase inhibitory properties. The antimicrobial activity was carried out in vitro by the broth dilution ***: Trans-cinnamic acid, rutin hydrate, naringin and quercetin were the main compounds of the ethyl acetate extract from H. cheirifolia L. This extract has significant scavenging activity to decrease free radicals especially for DPPH and ABTS radicals. As well as, the ethyl acetate extract exhibited an antimicrobial property against bacterial strains. Bacillus licheniformis and Salmonella enterica were the most sensitive strains with minimum inhibitory concentration values of 0.156 mg/***: The ethyl acetate extract was found to be selectively antioxidant and antimicrobial.

关键词： Hertia cheirifolia Phytochemical analysis Antioxidant Antimicrobial α-Glucosidase inhibitory

Effects of using sinusoidal porous object(SPO)and perforated porous object(PPO)on the cooling performance of nano-enhanced multiple slot jet impingement for a conductive panel system

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Propulsion and Power Research 2024年第2期13卷 166-177页

作者： Fatih Selimefendigil Faiza Benabdallah kaouther Ghachem Hind Albalawi Badr MAlshammari Lioua Kolsi Department of Mechanical Engineering College of EngineeringKing Faisal UniversityAl Ahsa 31982Saudi Arabia Department of Mechanical Engineering Celal Bayar UniversityManisa 45140Turkey Department of Industrial Engineering and Systems College of EngineeringPrincess Nourah Bint Abdulrahman UniversityP.O.Box 84428Riyadh 11671Saudi Arabia Department of Physics College of SciencesPrincess Nourah Bint Abdulrahman UniversityP.O.Box 84428Riyadh 11671Saudi Arabia Department of Electrical Engineering College of EngineeringUniversity of Ha’ilHa’il City 81451Saudi Arabia Department of Mechanical Engineering College of EngineeringUniversity of Ha’ilHa’il City 81451Saudi Arabia

Cooling system design for thermal management of electronic equipment,batteries and photovoltaic(PV)modules is important for increasing the efficiency,safety operation,and long life span the *** the present study,two different cooling systems are proposed with nano-enhanced multiple impinging jets for a conductive *** present cooling systems can be used in electronic cooling and PV *** porous object(PPO)and sinusoidal porous object(SPO)are used in the jet cooling system.2D numerical analysis usingfinite volume method is conducted considering different values of permeability of the objects(Darcy number(Da)between 10^(-6) and 10^(-1)).When PPO is used in the cooling system,num-ber of cylinders(between 1 and 6),and size of the cylinders(between 0.015 and 0.075)are *** the case of using SPO,amplitude(between 0.1 and 2)and wave number(be-tween 1 and 12)are ***-water nanofluid with cylindrical shaped nanoparticles is used as the heat *** permeability is changed for PPO,the average temper-ature increases by roughly 3.89℃ for a single cylinder and drops by roughly 0.57℃ for a six-cylinder *** the size of the cylinder in the PPO case at highest permeability results in temperature drop of 5.3℃.When changing the number of cylinders,cooling rate varies by about 3.6%.Wave number of SPO is more influential on the cooling performance enhancement as compared to amplitude and permeability of the *** average surface temperature drops by 12.4℃ when the wave number is increased to *** compared to reference case of jet impingement cooling without porous object,using PPO and SPO along with the nanofluid result in temperature drop of 12.3℃ and 14.4℃.

关键词： Thermal management Jet impingement Perforated porous

Antimicrobial activity of Tunisian Euphorbia paralias L.

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Asian Pacific Journal of Tropical Biomedicine 2017年第7期7卷 629-632页

作者： Malek Besbes Hlila kaouther Majouli Hichem Ben Jannet Mahjoub Aouni Maha Mastouri Boulbaba Selmi Laboratory of Transmissible Diseases and Biological Active Substances Department of Pharmaceutical Sciences Faculty of Pharmacy University of Monastir Avenue Avicenne 5000 Monastir Tunisia Laboratory of Biochemistry Research Unit:UR 12ES08'Cell Signaling and Pathologies' Department of Biology Faculty of Medicine University of Monastir Monastir Tunisia Laboratory of Heterocyclic Chemistry Natural Products and Reactivity Team:Medicinal Chemistry and Natural Products Department of Chemistry Faculty of Sciences of Monastir University of Monastir Monastir Tunisia Laboratory of Bioresources:Integrative Biology and Exploiting Higher Institute of Biotechnology of Monastir Department of Molecular Biology Cellular and Biotechnology University of Monastir Monastir Tunisia

Objective: To examine the potential antimicrobial activity of Euphorbia paralias L. (Euphorbiaeae) leaves and stems extracts. Methods: The antimicrobial activity was tested against six microbial strains:Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633, Salmonella enterica CIP 8039, Staphy-lococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 9027 and Candida albicans ATCC 90028 by two different methods, the disk method and the dilution method. Results: Our results showed the important antimicrobial activity of the chloroform extract of the stems towards the majority of the strains by using both methods. Bacillus subtilis was the most sensitive strain (MIC=MBC=15μg/mL). Conclusion: Thus, some extracts of Euphorbia paralias can be used in the treatment of infectious diseases caused by microbes.

关键词： Euphorbia paralias L. Antimicrobial activity MIC MBC

Heat and mass transfer enhancement in triangular pyramid solar still using CNT-water nanofluid

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Journal of Central South University 2021年第11期28卷 3434-3448页

作者： GHACHEM kaouther KOLSI Lioua LARGUECH Samia ALNEMER Ghada Department of Industrial Engineering and Systems College of EngineeringPrincess Nourah bint Abdulrahman UniversityRiyadhSaudi Arabia Department of Mechanical Engineering College of EngineeringHa’il UniversityHa’il CitySaudi Arabia Research Laboratory of Metrology and Energy Systems National Engineering SchoolEnergy Engineering DepartmentUniversity of MonastirMonastir 5000Tunisia Department of Electrical Engineering College of EngineeringPrincess Nourah bint Abdulrahman UniversityRiyadhSaudi Arabia Department of Mathematical Science College of SciencePrincess Nourah bint Abdulrahman UniversityRiyadhSaudi Arabia

This work represents a 3 D numerical study of the effects of carbon nanotube(CNT)-water nanofluids on the double diffusive convection inside the triangular pyramid solar *** numerical investigation is performed for wide ranges of governing parameters such as buoyancy ratio(-10≤N≤0),volumetric fraction of nanoparticles(0≤Φ≤0.05) and Rayleigh number(10^(3)≤Ra≤10^(5)).The results are presented in terms of flow structure,temperature field,heat and mass transfer rates *** was found that the buoyancy ratio can be considered as an optimizing parameter for the heat and mass transfer,and the use of CNT has a positive effect on the solar still performances.

关键词： 3D solar still triangular pyramid solar still double diffusive convection CNT-water nanofluid