Mechanical buckling of FG-CNTs reinforced composite plate with parabolic distribution using Hamilton's energy principle

Tayeb, Tayeb Si,Zidour, Mohamed,Bensattalah, Tayeb,Heireche, Houari,Benahmed, Abdelillah,Bedia, E.A. Adda Techno-Press 2020 Advances in nano research Vol.8 No.2

The incorporation of carbon nanotubes in a polymer matrix makes it possible to obtain nanocomposite materials with exceptional properties. It's in this scientific background that this work was based. There are several theories that deal with the behavior of plates, in this research based on the Mindlin-Reissner theory that takes into account the transversal shear effect, for analysis of the critical buckling load of a reinforced polymer plate with parabolic distribution of carbon nanotubes. The equations of the model are derived and the critical loads of linear and parabolic distribution of carbon nanotubes are obtained. With different disposition of nanotubes of carbon in the polymer matrix, the effects of different parameters such as the volume fractions, the plate geometric ratios and the number of modes on the critical load buckling are analysed and discussed. The results show that the critical buckling load of parabolic distribution is larger than the linear distribution. This variation is attributed to the concentration of reinforcement (CNTs) at the top and bottom faces for the X-CNT type which make the plate more rigid against buckling.

Is it Necessary to Submit Grossly Normal Looking Gall Bladder Specimens for Histopathological Examination?

Tayeb, Muhammad,Rauf, Fozia,Ahmad, Khurshid,Khan, Faiz Muhammad Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.4

Background: The objectives of the study were to: 1) determine the frequency of incidental malignancy in unsuspected/grossly normal looking gall bladders; 2) determine the frequency of malignancy in suspected/grossly abnormal looking gall bladders. Materials and Methods: This prospective, cross sectional study was carried out at a tertiary care hospital in Pakistan, during a four year period (Jan 2009-dec2012). All the cholecystectomy cases performed for gallstone diseases were examined initially by a surgeon and later on by a pathologist for macroscopic abnormalities and accordingly assigned to one of the three categories i.e. grossly normal, suspicious, abnormal/malignant. Frequency of incidental carcinoma in these categories was observed after receiving the final histopathology report. Results: A total of 426 patients underwent cholecystectomy for cholelithiasis, with a 1:4 male: female ratio. Mean age of the patients was 45 years with a range of 17-80 years. The frequency of incidental gallbladder carcinoma was found to be 0.70 %(n=3). All the cases of gallbladder carcinoma were associated with some macroscopic abnormality. Not a single case of incidental carcinoma gallbladder was diagnosed in 383 'macroscopically normal looking' gallbladders. Conclusions: Incidental finding of gall bladder cancer was not observed in any of macroscopically normal looking gall bladders and all the cases reported as carcinoma gallbladder had some gross abnormality that made them suspicious. We suggest histopathologic examination of only those gall bladders with some gross abnormality.

Theoretical analysis of chirality and scale effects on critical buckling load of zigzag triple walled carbon nanotubes under axial compression embedded in polymeric matrix

Tayeb Bensattalah,Mohamed Zidour,Tahar Hassaine Daouadji,Khaled Bouakaz 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.3

Using the non-local elasticity theory, Timoshenko beam model is developed to study the non- local buckling of Triple-walled carbon nanotubes (TWCNTs) embedded in an elastic medium under axial compression. The chirality and small scale effects are considered. The effects of the surrounding elastic medium based on a Winkler model and van der Waals’ (vdW) forces between the inner and middle, also between the middle and outer nanotubes are taken into account. Considering the small-scale effects, the governing equilibrium equations are derived and the critical buckling loads under axial compression are obtained. The results show that the critical buckling load can be overestimated by the local beam model if the small-scale effect is overlooked for long nanotubes. In addition, significant dependence of the critical buckling loads on the chirality of zigzag carbon nanotube is confirmed. Furthermore, in order to estimate the impact of elastic medium on the non-local critical buckling load of TWCNTs under axial compression, the use of these findings are important in mechanical design considerations, improve and reinforcement of devices that use carbon nanotubes.

Effect of Dune Sand on the Properties of Flowing Sand-Concrete (FSC)

Tayeb Bouziani,Madani Bederina,Mourad Hadjoudja 한국콘크리트학회 2012 International Journal of Concrete Structures and M Vol.6 No.1

Sand-concrete is being researched for potential usage in construction in Saharan regions of Algeria, because of shortage in coarse aggregate resources. This research work deals with the effect of dune sand, available in huge quantities in these regions, on the properties of flowing sand-concrete (FSC) prepared with different proportions of dune and river sands. Mini-cone slump test, v-funnel flow-time test and viscosity measurements were used to characterize the behaviour of FSC in fresh state. The 28- day compressive strength was also determined. Test results show that an optimal content of dune sand, which makes satisfied fresh and hardened properties of FSC, is obtained. Moreover, the obtained flow index (constant b) calculated by the help of power-law viscosity model is successfully correlated to the experimental results of v-funnel flow time.

Essential oils composition of diff erent Achillea santolina L. plant parts growing in Algeria

Tayeb Berramdane,Nadhir Gourine,Abdelghani Zitouni,Isabelle Bombarda,Mohamed Yousfi 경희대학교 융합한의과학연구소 2018 Oriental Pharmacy and Experimental Medicine Vol.18 No.3

The essential oils (EOs) of leaves, fl owers and stems of Achillea santolina L. (Asteraceae) collected at complete fl owering stage from Southwest of Algeria, were isolated by hydrodistillation and subsequently analyzed by means of GC and GC/MS. Quantitative and qualitative diff erences in chemical compositions between the studied parts of this plant were observed. The EOs were rich in oxygenated monoterpenes (65.91–79.94%). The major constituents in the fl owers, leaves and stems were: camphor (68.12, 65.17, 55.72%), 1,8-cineole (8.22, 4.77, 0.7%) and α-terpineol (2.84, 5.35, 2.76%). The highest EO yields were obtained for the leaves and the fl owers (0.59 and 0.49% “v/w”, respectively), whereas, the stems were characterized by very weak yield value (0.05%).

Is the Fundamental Matrix Really Independent of the Scene Structure?

Tayeb Basta 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5

In stereo vision, two images of a 3D scene are acquired from two viewpoints. One of the objectives of stereo vision work is to recover the 3D structure of the scene. Epipolar geometry describes the relationship between the images, and the essential and fundamental matrices are the algebraic representations of this geometry. The most important feature of these matrices that is emphasized in the literature is that they are independent of the scene structure. This article illustrates—empirically and theoretically—that the fundamental matrix depends on the scene structure and demonstrates that the matrix in 0lrFmm not only represents a relationship between corresponding points of the two views but also represents a relationship between other non-corresponding points. Furthermore, we show empirically that the equation 0lrFmm does not hold for any pair of corresponding points. In scenes with objects of different depths, the value of lrFmm depends on the depths of the 3D points and increases proportionally with an increasing baseline.

Improved analytical solution for slip and interfacial stress in composite steel-concrete beam bonded with an adhesive

Tayeb, Bensatallah,Daouadji, Tahar Hassaine Techno-Press 2020 Advances in materials research Vol.9 No.2

In this paper, an improved theoretical interfacial stress and slip analysis is presented for simply supported composite steel-concrete beam bonded with an adhesive. The adherend shear deformations have been included in the present theoretical analyses by assuming a linear shear stress through the thickness of the adherends, while all existing solutions neglect this effect. Remarkable effect of shear deformations of elements has been noted in the results. It is observed that large shear is concentrated and slip at the edges of the composite steel-concrete. Comparing with some experimental results from references, analytical advantage of this improvement is possible to determine the normal and shear stress to estimate exact prediction of normal and shear stress interfacial along span between concrete and steel beam. The exact prediction of these stresses will be very important to make an accurate analysis of the mode of fracture. It is shown that both the normal and shear stresses at the interface are influenced by the material and geometry parameters of the composite steel-concrete beam. This research is helpful for the understanding on mechanical behavior of the connection and design of such structures.

A simple test method to assess slump flow and stability of self-compacting concrete

Tayeb Bouziani 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.2

Establishment of test methods to assess the fresh properties of self-compacting concrete (SCC) are required to ensure the homogeneity in fresh and hardened states. This paper discusses the suitability of a simple test method for assessing the slump flow and stability of SCC by testing on self-compacting mortar (SCM) fraction. The proposed test method aims at investigating slump flow diameter test and sieve stability test of SCC by testing SCM fraction with a plunger penetration apparatus. A central composite modeling design was performed to evaluate the effects of water/cement ratio (W/C), superplasticizer dosage (SP) and powder marble content (MP) on slump flow diameter, stability and plunger penetration test of fresh SCC. The responses of the derived statistical models are slump flow (Sf), sieve stability (S) and plunger penetration (P). Relationships obtained in this study show acceptable correlations between plunger penetration test value and slump flow diameter test results and stability. It should note that the developed relationships are very useful to predict slump flow diameter and stability of studied SCC mixtures by carrying out a simple plunger penetration test on its mortar, which can save labour and time in laboratory experiments.

Effect of Dune Sand on the Properties of Flowing Sand-Concrete (FSC)

Bouziani, Tayeb,Bederina, Madani,Hadjoudja, Mourad Korea Concrete Institute 2012 International Journal of Concrete Structures and M Vol.6 No.1

Sand-concrete is being researched for potential usage in construction in Saharan regions of Algeria, because of shortage in coarse aggregate resources. This research work deals with the effect of dune sand, available in huge quantities in these regions, on the properties of flowing sand-concrete (FSC) prepared with different proportions of dune and river sands. Mini-cone slump test, v-funnel flow-time test and viscosity measurements were used to characterize the behaviour of FSC in fresh state. The 28-day compressive strength was also determined. Test results show that an optimal content of dune sand, which makes satisfied fresh and hardened properties of FSC, is obtained. Moreover, the obtained flow index (constant b) calculated by the help of power-law viscosity model is successfully correlated to the experimental results of v-funnel flow time.

Analytical analysis for the forced vibration of CNT surrounding elastic medium including thermal effect using nonlocal Euler-Bernoulli theory

Bensattalah, Tayeb,Zidour, Mohamed,Daouadji, Tahar Hassaine Techno-Press 2018 Advances in materials research Vol.7 No.3

This article studies the free and forced vibrations of the carbon nanotubes CNTs embedded in an elastic medium including thermal and dynamic load effects based on nonlocal Euler-Bernoulli beam. A Winkler type elastic foundation is employed to model the interaction of carbon nanotube and the surrounding elastic medium. Influence of all parameters such as nonlocal small-scale effects, high temperature change, Winkler modulus parameter, vibration mode and aspect ratio of short carbon nanotubes on the vibration frequency are analyzed and discussed. The non-local Euler-Bernoulli beam model predicts lower resonance frequencies. The research work reveals the significance of the small-scale coefficient, the vibrational mode number, the elastic medium and the temperature change on the non-dimensional natural frequency.