Experimental Study of Steel Fiber Concrete Slabs Part I: Behavior under Uniformly Distributed Loads

Ellouze, Ali,Ouezdou, Mongi Ben,Karray, Mohammed Ali Korea Concrete Institute 2010 International Journal of Concrete Structures and M Vol.4 No.2

This article aims to study the effects of adding steel fibers to concrete on the mechanical behavior of steel fiber concrete (SFC) slabs. After formulating the SFC, an experimental work was, first, conducted on $160\;{\times}\;320$ mm cylindrical specimens and $70\;{\times}\;70\;{\times}\;280$ mm prisms. Then, this study was carried out on 20 rectangular $1,100\;{\times}\;1,100\;{\times}\;60$ mm small slabs submitted to a distributed load. Two types of fibers with hooked ends were used: long fibers (LF) of a length of 50 mm and short fibers (SF) of a length of 35 mm. The studied parameters are compressive and tensile strengths and Young's modulus. Plain concrete (PC) small slabs were also prepared to be compared to the SFC specimens. The results showed that the compressive strength of SFC increased up to 25% while the splitting tests showed an improvement of the SFC reaching 45%. Tests on SFC small slabs also showed that a smaller deflection is obtained with respect to PC, which indicates an improvement in strength (up to 100%), in ductility and in resistance to cracking. The LF gives a better improvement in strength than the SF for a 70% $kg/m^3$ of steel proportioning.

PRACTICAL OBSERVER FOR IMPULSIVE SYSTEMS

Ellouze, Imen Korean Mathematical Society 2014 대한수학회지 Vol.51 No.1

In this paper, we deal with the problem of practical observer design and the practical stabilization for a class of perturbed impulsive systems. We show that, under the classical conditions of uniform complete controllability and uniform complete observability of the nominal system without impulsive effects, it is possible to design an observer controller for a class of perturbed linear impulsive system when the origin is not an equilibrium point.

PRACTICAL OBSERVER FOR IMPULSIVE SYSTEMS

Imen Ellouze 대한수학회 2014 대한수학회지 Vol.51 No.1

In this paper, we deal with the problem of practical observer design and the practical stabilization for a class of perturbed impulsive systems. We show that, under the classical conditions of uniform complete controllability and uniform complete observability of the nominal system without impulsive effects, it is possible to design an observer controller for a class of perturbed linear impulsive system when the origin is not an equilibrium point.

Experimental Study of Steel Fiber Concrete Slabs Part I

Ali Ellouze,Mongi Ben Ouezdou,Mohammed Ali Karray 한국콘크리트학회 2010 International Journal of Concrete Structures and M Vol.4 No.2

This article aims to study the effects of adding steel fibers to concrete on the mechanical behavior of steel fiber concrete (SFC) slabs. After formulating the SFC, an experimental work was, first, conducted on 160 × 320 mm cylindrical specimens and 70 × 70 × 280 mm prisms. Then, this study was carried out on 20 rectangular 1,100 × 1,100 × 60 mm small slabs submitted to a distributed load. Two types of fibers with hooked ends were used: long fibers (LF) of a length of 50 mm and short fibers (SF) of a length of 35 mm. The studied parameters are compressive and tensile strengths and Young"s modulus. Plain concrete (PC) small slabs were also prepared to be compared to the SFC specimens. The results showed that the compressive strength of SFC increased up to 25% while the splitting tests showed an improvement of the SFC reaching 45%. Tests on SFC small slabs also showed that a smaller deflection is obtained with respect to PC, which indicates an improvement in strength (up to 100%), in ductility and in resistance to cracking. The LF gives a better improvement in strength than the SF for a 70% kg/m³ of steel proportioning.

Cloning and molecular characterization of a new fungal xylanase gene from Sclerotinia sclerotiorum S2

( Olfa Elleuch Ellouze ),( Sana Loukil ),( Mohamed Nejib Marzouki ) 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.10

Sclerotinia sclerotiorum fungus has three endoxylanases induced by wheat bran. In the first part, a partial xylanase sequence gene (90 bp) was isolated by PCR corresponding to catalytic domains (β 5 and β 6 strands of this protein). The high homology of this sequence with xylanase of Botryotinia fuckeliana has permitted in the second part to amplify the XYN1 gene. Sequence analysis of DNA and cDNA revealed an ORF of 746 bp interrupted by a 65 bp intron, thus encoding a predicted protein of 226 amino acids. The mature enzyme (20.06 kDa), is coded by 188 amino acid (pI 9.26). XYN1 belongs to G/11 glycosyl hydrolases family with a conserved catalytic domain containing E86 and E178 residues. Bioinformatics analysis revealed that there was no Asn-X-Ser/Thr motif required for N-linked glycosylation in the deduced sequence however, five O-glycosylation sites could intervene in the different folding of xylanses isoforms and in their secretary pathway. [BMB reports 2011; 44(10): 653-658]

Improvement of Bread Quality and Bread Shelf-life by Bacillus subtilis Biosurfactant Addition

Ines Mnif,Souhail Besbes,Raoudha Ellouze,Semia Ellouze-Chaabouni,Dhouha Ghribi 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.4

The objective of the present work was to determine the effect of the addition of a microorganism derived emulsifier on the quality of bread. The effect of Bacillus subtilis SPB1 biosurfactant has been investigated in comparison to a commercial surfactant, the soya lecithin. Indeed, it led to a better shape and a greater specific volume and voided fraction of loaves. Also, results showed that SPB1 bioemulsifier addition improved considerably the texture profile of bread, mainly at a concentration of 0.075%(w/w). In fact, we showed a notable decrease of firmness, chewiness, and adhesion values with a slight increase of cohesion for bread added emulsifier. According to crumb texture evolution during storage, SPB1 biosurfactant exhibited a significant antistaling effect. Moreover, SPB1biosurfactant addition reduced significantly bread susceptibility to microbial contamination. These results proved that SPB1 biosurfactant could be of a great interest in the bread-making industry.

Fouling mechanism and screening of backwash parameters

Fatma Zohra Slimane,Fatma Ellouze,Nihel Ben Amar 대한환경공학회 2019 Environmental Engineering Research Vol.24 No.2

This work deals with the membrane fouling mode and the unclogging in seawater ultrafiltration process. The identification of the fouling mechanism by modeling the experimental flux decline was performed using both the classical models of Hermia and the combined models of Bolton. The results show that Bolton models did not bring more precise information than the Hermia’s and the flux decline can be described by one of the four Hermia’s models since the backwash interval is ≤ 60 min. An experimental screening study has been then conducted to choose among 5 parameters (backwash interval, duration, pulses and the flow-rate or injected hypochlorite concentration) those that are the most influential on the fouling and the net water production. It has emerged that fouling is mainly affected by the backwash interval; its prolongation from 30 to 60 min engenders an increase in the reversible fouling and a decrease in the irreversible fouling. This later is also significantly reduced when the hypochlorite concentration increases from 4.5 to 10 ppm. Moreover, the net water production significantly increases with increasing the filtration duration up to 60 min and decreases with decreasing the backwash duration and backwash flow-rate from 10 to 40 s and from 15 to ≥ 20 L.min<SUP>-1</SUP>, respectively.

Magnetic, thermoelectric properties and magnetocaloric effect of Pr0.7Ba0.3MnO3 perovskite: experimental, DFT calculation and Monte Carlo simulations

Masrour R.,Kadim G.,Ellouze M. 한국세라믹학회 2024 한국세라믹학회지 Vol.61 No.3

The magnetic, electronic, structural, thermoelectric properties and magnetocaloric eff ect of Pr 0.75Ba0.25MnO3 perovskite using, experimental, DFT calculation and Monte Carlo simulations were investigated. The ground state has half-metallic character. Our calculations also show that the Pr 0.75Ba0.25MnO3 has a ferromagnetic behavior. Pr 0.75Ba0.25MnO3 exhibits p-type behavior with dominant holes as the primary carriers, as indicated by its thermoelectric properties. This system exhibits a ferromagnetic–Paramagnetic transition. We have successfully obtained several properties, including magnetization, specifi c heat, variation of specifi c heat, magnetic entropy changes, relative cooling power, and the magnetic hysteresis cycle. For a magnetic fi eld change of 5 T, the maximum value of the magnetic entropy change (∣Δ Smax∣) was approximately 12 J/ kg.K, while the relative cooling power (RCP) reached 126 J/kg. The promising potential of the present system for magnetic refrigeration is evident due to its relatively large values of ∣Δ Smax∣ and RCP. Finally, the thermoelectric properties were given.

Improved Biosurfactant Production by Bacillus subtilis SPB1 Mutant Obtained by Random Mutagenesis and Its Application in Enhanced Oil Recovery in a Sand System

( Mouna Bouassida ),( Imen Ghazala ),( Semia Ellouze-chaabouni ),( Dhouha Ghribi ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.1

Biosurfactants or microbial surfactants are surface-active biomolecules that are produced by a variety of microorganisms. Biodegradability and low toxicity have led to the intensification of scientific studies on a wide range of industrial applications for biosurfactants in the field of environmental bioremediation as well as the petroleum industry and enhanced oil recovery. However, the major issues in biosurfactant production are high production cost and low yield. Improving the bioindustrial production processes relies on many strategies, such as the use of cheap raw materials, the optimization of medium-culture conditions, and selecting hyperproducing strains. The present work aims to obtain a mutant with higher biosurfactant production through applying mutagenesis on Bacillus subtilis SPB1 using a combination of UV irradiation and nitrous acid treatment. Following mutagenesis and screening on blood agar and subsequent formation of halos, the mutated strains were examined for emulsifying activity of their culture broth. A mutant designated B. subtilis M2 was selected as it produced biosurfactant at twice higher concentration than the parent strain. The potential of this biosurfactant for industrial uses was shown by studying its stability to environmental stresses such as pH and temperature and its applicability in the oil recovery process. It was practically stable at high temperature and at a wide range of pH, and it recovered above 90% of motor oil adsorbed to a sand sample.

Principal temporal extensions of SOM : Overview (pp.121-134)

Mohamed Salah Salhi,Najet Arous,Noureddine Ellouze 보안공학연구지원센터(IJSIP) 2009 International Journal of Signal Processing, Image Vol.2 No.3