Bending analysis of functionally graded thick plates with in-plane stiffness variation

Mazari, Ali,Attia, Amina,Sekkal, Mohamed,Kaci, Abdelhakim,Tounsi, Abdelouahed,Bousahla, Abdelmoumen Anis,Mahmoud, S.R. 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.4

In the present paper, functionally graded (FG) materials are presented to investigate the bending analysis of simply supported plates. It is assumed that the material properties of the plate vary through their length according to the power-law form. The displacement field of the present model is selected based on quasi-3D hyperbolic shear deformation theory. By splitting the deflection into bending, shear and stretching parts, the number of unknowns and equations of motion of the present formulation is reduced and hence makes them simple to use. Governing equations are derived from the principle of virtual displacements. Numerical results for deflections and stresses of powerly graded plates under simply supported boundary conditions are presented. The accuracy of the present formulation is demonstrated by comparing the computed results with those available in the literature. As conclusion, this theory is as accurate as other shear deformation theories and so it becomes more attractive due to smaller number of unknowns. Some numerical results are provided to examine the effects of the material gradation, shear deformation on the static behavior of FG plates with variation of material stiffness through their length.

Bending analysis of functionally graded thick plates with in-plane stiffness variation

Ali Mazari,Amina Attia,Mohamed Sekkal,Abdelhakim Kaci,Abdelouahed Tounsi,Abdelmoumen Anis Bousahla,S. R. Mahmoud 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.4

In the present paper, functionally graded (FG) materials are presented to investigate the bending analysis of simply supported plates. It is assumed that the material properties of the plate vary through their length according to the power-law form. The displacement field of the present model is selected based on quasi-3D hyperbolic shear deformation theory. By splitting the deflection into bending, shear and stretching parts, the number of unknowns and equations of motion of the present formulation is reduced and hence makes them simple to use. Governing equations are derived from the principle of virtual displacements. Numerical results for deflections and stresses of powerly graded plates under simply supported boundary conditions are presented. The accuracy of the present formulation is demonstrated by comparing the computed results with those available in the literature. As conclusion, this theory is as accurate as other shear deformation theories and so it becomes more attractive due to smaller number of unknowns. Some numerical results are provided to examine the effects of the material gradation, shear deformation on the static behavior of FG plates with variation of material stiffness through their length.

Pakistan, the NPT and the Non-Proliferation Regime

( Shireen M Mazari ) 한국국방연구원 2003 The Korean Journal of Defense Analysis Vol.15 No.2

The article deals with the notion of Arms Control and Disarmament (AC&D), and argues that the two concepts are not linked but are conceptually distinguishable. Arms control can often hinder disarmament. For the developed states, the concept has evolved primarily in terms of economic efficiency and cost-effectiveness, whereas for the developing states, AC&D has been aimed at control of technology, rather than an overall effort to reduce arms levels. Pakistan`s approach to AC&D has been dominated by its regional defense and security concerns in relation to its conflictive relationship with India. Pakistan has also been aware of the discriminatory approach of the Western powers in dealing with Pakistan and Indian nuclear programs. Thus, while India`s nuclear program received US support, Pakistan, on the other hand was put under severe sanctions. However, despite these crippling sanctions, which were lifted only after the events of September 11, Pakistan continues to seek both multilateral and bilateral measures to enforce nuclear non-proliferation in South Asia, including a proposal for a nuclear free zone in the region.

Performance Characterization and Pressure Prediction of Compression Socks

Hafiz Faisal Siddique,Adnan Ahmed Mazari,Antonin Havelka,Zdenek KUS 한국섬유공학회 2020 Fibers and polymers Vol.21 No.3

Objective of the current research is to develop the mathematical model for the prediction of compression pressureby incorporating some of new but missing variables; circumferential aspect of leg (Lc) and socks (Sc), true stress (σT), true/logarithm strain (εT), true modulus of elasticity (ET), deformed width (Wf) at b ankle position. Socks samples were purchased,hand washed, donned, marked, sliced to loops and then cut to rectangular strips to obtain force-elongation curve at differentextensions context to practical elongation. Additionally, all samples were evaluated to analyze the influnce of multiplemachinewashes as well as for identification of most influential fabric parameter on compresson pressure, statistically. Standard sized wooden leg (S9=24 cm) attached with pneumatic based sensors (Salzmann MST MK IV) to medial side wasused. Force-extension diagram was obtained using Testometric tensile tester. Mathematical models were developed on thebasis of principle of Laplace’s law. Developed two models were analyzed and comapred with two existing recently developedmodels statitistically using MINTAB 17 software.

Plastic energy approach prediction of fatigue crack growth

Sofiane Maachou,Abdelkader Boulenouar,Mohamed Benguediab,Mohamed Mazari,Narayanaswami Ranganathan 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.5

The energy-based approach to predict the fatigue crack growth behavior under constant and variable amplitude loading (VAL) of the aluminum alloy 2024 T351 has been investigated and detailed analyses discussed. Firstly, the plastic strain energy was determined per cycle for different block load tests. The relationship between the crack advance and hysteretic energy dissipated per block can be represented by a power law. Then, an analytical model to estimate the lifetime for each spectrum is proposed. The results obtained are compared with the experimentally measured results and the models proposed by Klingbeil\'s model and Tracey\'s model. The evolution of the hysteretic energy dissipated per block is shown similar with that observed under constant amplitude loading.

Performance Characterization of Compression Socks at Ankle Portion under Multiple Mechanical Impacts

Hafiz Faisal Siddique,Adnan Ahmed Mazari,Antonin Havelka,Zdenek KUS 한국섬유공학회 2019 Fibers and polymers Vol.20 No.5

The aim of this research is to investigate how performance of compression socks is deteriorated due to expectedinduced wearing mechanical impacts. Wearing mechanical impacts influence the durability parameters i.e. tensile energyloss, extent of pressure deterioration and dimensional deformation. This research is comprised of two parts; 1): Comparisonof unwashed and hand washed cut-strips for tensile energy and dimensional deformation. For tensile energy loss, cut-stripsamples were-interacted to constant rate of loading and un-loading, cyclic-loading upto 15th cycles for ±5 mm extension(considering muscles expansion and relaxation) and were dwelled (stayed) for 3 minutes at 25 %, 50 % and 75 % extensionlevels, simultaneously. As a second part 2); Three levels (1st, 2nd and 3rd) of gradual intensive machine washes wereperformed to quantify the extent of deterioration of compression pressure, worn alternatively on a fixed sized plastic leg,using KIKUHIME pressure measuring device. Dimensional deformation due to hand washing while dimensional recovery;immediately after pressure measurement (after Pr.), and a-day-later after pressure measurement (dL Pr.) was compared andstatistically analyzed. Statistical validation of second part was performed by introducing measures of correlation, p-value(≤ 0.05), R-square values using MINITAB 17 software.

Harvesting Electricity from CO2 Emission: Opportunities, Challenges and Future Prospects

Peter Adeniyi Alaba,Shaukat Ali Mazari,Hamisu Umar Farouk,Samuel Eshorame Sanni,Oluranti Agboola,Ching Shya Lee,Faisal Abnisa,Mohamed Kheireddine Aroua,Wan Mohd Ashri Wan Daud 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.3

The ever-increasing CO2 emission has necessitated the search for suitable technologies for CO2 utilization at a low cost. Recently, a novel concept called reactive gas electrosorption (RGE) for energy harvesting from CO2 emission, which could boost the efficiency of a thermal power plant by 5% was proposed by Hamelers and coworkers. The concept involves mixing of air stream with a low CO2 concentration with a stream of high CO2 concentration in an alkaline aqueous electrolyte. However, this concept is faced with the challenges of designs specific for CO2-electrolyte, and inadequate performance of the electrode materials. Therefore, this study showcases electricity generation opportunities from CO2 via RGE and discussed challenges and prospect. The study reveals that the drawback relating to the electrode could be solved using heteroatom doped traditional carbon materials and composite carbon-based materials, which has been successfully used in capacitive cells designed for desalination. This modification helps to improve the hydrophilicity, thereby improving electrode wettability, and suppressing faradaic reaction and co-ion repulsion effect. This improvement could enhance the charge efficiency, sorption capacity durability of electrodes and reduce the energy loss in RGE. Moreover, intensification of the membrane capacitive deionization (MCDI) process to obtain variances like enhanced MCDI and Faradaic MCDI. Hybrid capacitive deionization (HCDI) is also a promising approach for improvement of the capacitive cell design in RGE. This intensification can improve the electrosorption capacity and minimize the negative effect of faradaic reaction. The use of alternative amine like Piperazine, which is less susceptible to degradation to boosting CO2 dissolution is also suggested.

Assessment of the cytotoxic activity and the reduction power of Limoniastrum feei Girard (Batt.): a medicinal plant from Algerian Sahara

Imad Abdelhamid El Haci,Wissame Mazari,Fawzia Atik-Bekkara,Fayçal Hassani,Mohamed Gherib 경희대학교 융합한의과학연구소 2017 Oriental Pharmacy and Experimental Medicine Vol.17 No.2

This scientific work involves a phytochemical study of a medicinal plant endemic to the south of Algeria: Limoniatrum feei Girard (Batt.). The study of the antioxidant effects and the evaluation of the cytotoxicity were reported. Polar organic extracts: methanol, ethanol and acetone of L. feei presented considerable levels of phenols and flavonoids. These levels were ranged from 127.07 to 262.11 mg GAE/g and 84 to 157.88 mg CEQ/g, respectively. Considerable antioxidant activity of polar organic extracts of L. feei was revealed. In the DPPH scavenging method, methanolic extract expressed an IC50 of about 3.2 μg/mL which is comparable to that of the ascorbic acid (2.48 μg/mL). The same extract expressed strong antioxidant power against hydroxyl radical with an IC50 of about 36.33 μg/mL, which is higher than that of the ascorbic acid (61.83 μg/mL). In the test of the β-carotene bleaching, acetone extract expressed a remarkable antioxidant power comparable to the positive control (IC50: 5.85 μg/mL and 4.26 μg/mL, respectively). A low cytotoxic activity against human red blood cells was exerced by the methanol extract of L. feei, this could explaine the safety uses of this plant by indigenous populations.

Outcomes of Direct Infrapectineal Buttress Plate for Quadrilateral Surface Fractures of Acetabulum Using an Anterior Intrapelvic Approach

( Umair Nadeem ),( Irfan Qadir ),( Jahanzeb Mazari ),( Atiq Uz Zaman ),( Amer Aziz ) 대한고관절학회 2021 Hip and Pelvis Vol.33 No.1

Purpose: Reduction and stable fixation of the quadrilateral plate are challenging primarily due to its location in the true pelvis, limited bone stock, juxta-articular nature, and its comminution. The current study aimed to investigate the quality of reduction and functional outcomes after open reduction and internal fixation (ORIF) with infrapectineal buttress plating of the quadrilateral surface via an anterior intrapelvic approach. Materials and Methods: We conducted a retrospective review of twenty-one patients with acetabular fractures involving quadrilateral plate operated at Ghurki Trust Teaching Hospital between January 2017 and December 2018. Radiological assessment of the quality of reduction was conducted using criteria described by Matta. Functional outcomes were evaluated using a modified Postel Merle d’Aubigné score. Results: The current study included 15 males and 6 females with a mean age of 40.67±12.17 years (range, 22- 62 years). The most common fracture pattern was anterior column and posterior hemi-transverse in eight patients followed by true bicolumn and T-type fractures in seven and four patients respectively. Both transverse fractures were transtectal. The quality of reduction according to Matta criteria was anatomical in 14 patients, imperfect in five and poor in two. Functional outcomes were excellent in 47.6% cases, good in 42.9%, and fair in 9.5% cases. Both patients with fair outcomes had non-anatomical reduction, and one required total hip arthroplasty at a later time. Conclusion: Quadrilateral plate reconstruction with an infrapectineal buttress plate applied though an anterior intrapelvic approach provides high rates of anatomical reduction and yields good functional outcomes.

A review on the properties and applications of chitosan, cellulose and deep eutectic solvent in green chemistry

Xin Xiong Chang,Nabisab Mujawar Mubarak,Shaukat Ali Mazari,Abdul Sattar Jatoi,Awais Ahmad,Mohammad Khalid,Rashmi Walvekar,E.C. Abdullah,Rama Rao Karri,M.T.H Siddiqui,Sabzoi Nizamuddin 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-

The concept of green chemistry has attracted attention due to the green synthesis and ecofriendly natureof the compounds leading to the green and sustainable chemical industries and processes. Chitosan is anecofriendly material, which is biodegradable, non-toxic, and biocompatible. It has the potential to bemodified into biofilms for various applications such as biomedical, packaging, and pharmaceutical fields. Nevertheless, some poor properties of chitosan restrict its wide applications. The incorporation ofnanocellulose fillers into chitosan matrix can enhance the mechanical and thermal properties of chitosan. Cellulose nanomaterials can be achieved through chemical and mechanical modifications. The commontype of nanocellulose are cellulose nanofibers (CNFs), cellulose nano-whiskers (CNWs), tunicate CNCs (t-CNCs), algae cellulose particles (AC) and bacterial cellulose particles (BC). Nanocellulose are applied asthe reinforcement fillers in various polymer matrices such as polysaccharides, proteins, lipids, polylacticacid etc. Deep eutectic solvents (DES) are relatively novel green solvents, which can be applied in variousfields. DES are widely applied in metal processing, polymer processing and synthesis. Even though thereare not much studies available on DES for synthesis of nanocomposite films; however they are used aseco-friendly solvents in manufacturing processes. This study reviews the discovery, structure, propertiesof chitosan and cellulose, their derivatives and applications. In addition, the paper also discusses theproperties of DES and their applications.