Effectiveness of SWNT in reducing the crack effect on the dynamic behavior of aluminium alloy

Selmi, Abdellatif Techno-Press 2019 Advances in nano research Vol.7 No.5

This paper investigates the effectiveness of Single Walled Carbon Nanotubes, SWNT, in improving the dynamic behavior of cracked Aluminium alloy, Al-alloy, beams by using a method based on changes in modal strain energy. Mechanical properties of composite materials are estimated by the Eshelby-Mori-Tanaka method. The influence of SWNT volume fraction, SWNT aspect ratio, crack depth and crack location on the natural frequencies of the damaged 3D randomly oriented SWNT reinforced Al-alloy beams are examined. Results demonstrate the significant advantages of SWNT in reducing the effect of cracks on the natural frequencies of Al-alloy beams.

PROJECTIONS AND SLICES OF MEASURES

Selmi, Bilel,Svetova, Nina Korean Mathematical Society 2021 대한수학회논문집 Vol.36 No.2

We consider a generalization of the L^q-spectrum with respect to two Borel probability measures on ℝⁿ having the same compact support, and also study their behavior under orthogonal projections of measures onto an m-dimensional subspace. In particular, we try to improve the main result of Bahroun and Bhouri [4]. In addition, we are interested in studying the behavior of the generalized lower and upper L^q-spectrum with respect to two measures on "sliced" measures in an (n - m)-dimensional linear subspace. The results in this article establish relations with the L^q-spectrum with respect to two Borel probability measures and its projections and generalize some well-known results.

Free vibration of bi-dimensional functionally graded simply supported beams

Selmi, Abdellatif Techno-Press 2021 Advances in concrete construction Vol.12 No.3

This paper investigates the free vibration of bi-dimensional functionally graded simply supported beams by using the continuous element method. The material properties are considered to vary exponentially along the beam thickness and length. The characteristic frequency equations of simply supported beams are derived by transfer matrix method. Validation targets are other analytical methods. The effects of the gradient indexes and the beam slenderness ratio on the natural frequencies of bi-dimensional functionally graded beams are studied.

SOME RESULTS ABOUT THE REGULARITIES OF MULTIFRACTAL MEASURES

Selmi, Bilel The Kangwon-Kyungki Mathematical Society 2018 한국수학논문집 Vol.26 No.2

In this paper, we generelize the Olsen's density theorem to any measurable set, allowing us to extend the main results of H.K. Baek in (Proc. Indian Acad. Sci. (Math. Sci.) Vol. 118, (2008), pp. 273-279.). In particular, we tried through these results to improve the decomposition theorem of Besicovitch's type for the regularities of multifractal Hausdorff measure and packing measure.

ASYMPTOTIC STUDY OF MIXED ROTATING MHD SYSTEM

Selmi, Ridha Korean Mathematical Society 2010 대한수학회보 Vol.47 No.2

Asymptotic behavior of three-dimensional mixed, periodic and rotating magnetohydrodynamic system is investigated as the Rossby number goes to zero. The system presents the difficulty to be singular and mixed, that is hyperbolic in the vertical direction and parabolic in the horizontal one. The divergence free condition and the spectral properties of the penalization operator are crucial in the proofs. The main tools are the energy method, the Schochet's method and products laws in anisotropic Sobolev spaces.

Machine learning model for predicting ultimate capacity of FRP-reinforced normal strength concrete structural elements

Selmi Abdellatif,Ali Raza 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.85 No.3

Limited studies are available on the mathematical estimates of the compressive strength (CS) of glass fiberembedded polymer (glass-FRP) compressive elements. The present study has endeavored to estimate the CS of glass-FRP normal strength concrete (NSTC) compression elements (glass-FRP-NSTC) employing two various methodologies; mathematical modeling and artificial neural networks (ANNs). The dataset of 288 glass-FRP-NSTC compression elements was constructed from the various testing investigations available in the literature. Diverse equations for CS of glass-FRP-NSTC compression elements suggested in the previous research studies were evaluated employing the constructed dataset to examine their correctness. A new mathematical equation for the CS of glass-FRP-NSTC compression elements was put forwarded employing the procedures of curve-fitting and general regression in MATLAB. The newly suggested ANN equation was calibrated for various hidden layers and neurons to secure the optimized estimates. The suggested equations reported a good correlation among themselves and presented precise estimates compared with the estimates of the equations available in the literature with R2= 0.769, and R2 =0.9702 for the mathematical and ANN equations, respectively. The statistical comparison of diverse factors for the estimates of the projected equations also authenticated their high correctness for apprehending the CS of glass-FRP-NSTC compression elements. A broad parametric examination employing the projected ANN equation was also performed to examine the effect of diverse factors of the glass-FRP-NSTC compression elements.

Gastroprotective and Antioxidant Properties of Trigonella foenum graecum Seeds Aqueous Extract (Fenugreek) and Omeprazole Against Ethanol-Induced Peptic Ulcer

Slimen Selmi,Dhouha Alimi,Kais Rtibi,Saber Jedidi,Dhekra Grami,Lamjed Marzouki,Karim Hosni 한국식품영양과학회 2022 Journal of medicinal food Vol.25 No.5

Trigonella foenum graecum (Fenugreek) is used in traditional phytomedicine for its anti-inflammatory, antiseptic, antidiabetic, and several other therapeutic virtues. The current study was intended to investigate the protecting effects of fenugreek seeds’ aqueous extract (FSAE) using experimentally ethanol (EtOH)-induced gastric peptic ulcer in rats, as immense alcohol consumption can lead to gastric ulcer. Sixty adult male Wistar rats were divided into 6 groups of 10 each: control, EtOH (4 g/kg body weight [b.w.]), EtOH + several doses of FSAE (50, 100, and 200 mg/kg b.w.), and EtOH + Omeprazole (OM, 20 mg/kg orally [p.o.]). Animals were p.o. pretreated with FSAE for 21 days and exposed to a single oral administration of EtOH (4 g/kg b.w.) for 2 h. Gastric ulcer in rats was induced with a single dose of EtOH. Ulcer index, malondialdehyde (MDA), hydrogen peroxide (H2O2), and thiol groups (-SH) content in stomach, and antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured. Our recorded results showed that EtOH induced gastric damage, evidenced by the level of oxidative stress markers such as MDA and H2O2 in rats exposed to EtOH. However, significant increases in the activities of antioxidant enzymes were recorded, such as SOD, CAT, and GPx, and a decrease in nonenzymatic antioxidants, such as (-SH). Moreover, histopathological examinations showed the presence of lesions associated with severe tissue damage in the untreated rats. Interestingly, FSAE meaningfully protects against all gastric damages caused by EtOH. We propose that FSAE exhibits protective effects in EtOH-induced peptic ulcer in rats. This protection might be related to its antioxidant and anti-inflammatory properties as well as its opposite effects on some studied intracellular mediators.

Non-Alcoholic Fatty Liver Disease: The New Epidemic and the Need for Novel Nutritional Approaches

Carlo Selmi,Christopher L. Bowlus,Carl L. Keen,M. Eric Gershwin 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.4

The epidemic of non-alcoholic fatty liver disease (NAFLD) in the United States is staggering, and there is anenormous void in our understanding of the clinical epidemiology other than the common themes of obesity and insulin re-and appropriate nutritional supplements. There is, however, a wealth of basic science that helps to set the stage for definingthe mechanisms leading to liver pathology. In this article we will attempt to put these concepts in perspective to highlight theneed for future research including the use of medicinal food.

Vibration behavior of bi-dimensional functionally graded beams

Abdellatif Selmi 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.5

Based on Euler-Bernoulli beam theory and continuous element method, the free vibration of bi-dimensional functionally graded beams is investigated. It is assumed that the material properties vary exponentially along the beam thickness and length. The characteristic frequency equations of beams with different boundary conditions are obtained by transfer matrix method. The validity of the proposed method is assessed through comparison with available results. Parametric studies are carried out to analyze the influences of the gradient indexes and the beam slenderness ratio on the natural frequencies of bidimensional functionally graded beams.

ASYMPTOTIC STUDY OF MIXED ROTATING MHD SYSTEM

Ridha Selmi 대한수학회 2010 대한수학회보 Vol.47 No.2

Asymptotic behavior of three-dimensional mixed, periodic and rotating magnetohydrodynamic system is investigated as the Rossby number goes to zero. The system presents the difficulty to be singular and mixed,that is hyperbolic in the vertical direction and parabolic in the horizontal one. The divergence free condition and the spectral properties of the penalization operator are crucial in the proofs. The main tools are the energy method, the Schochet's method and products laws in anisotropic Sobolev spaces.