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Practically, the helical products used as a mechanical part to satisfy the needs of mechanical strength and artistic appearance. In addition, during recent 5 years it used to produce an ultra-fine grain metal structure. However, there are very little works regarding this type of extrusion so far. This work proposed a new formulation for helical deformation zone to produce general helical polygonal shapes through a streamlined die that are usually made by hot extrusion through taper die. The general die surface was represented analytically. The velocity and strain rate fields are derived depending on the volume constancy and the velocity boundary conditions. The upper bound forming pressure was obtained for various frictional conditions, area reduction, helix angle, and die length. The results show that the axis of the product does not rotate through the helical extrusion. The peak value of the strain rate is located close to the die outlet and decreases as the helix angle increases. The optimum die length becomes high as the helix angle increases. The forming pressure increases with increasing helix angle, area reduction, factor of friction, while decreases when the number of sides increases. The theoretical results were verified with previous work of zero twist and showed completely compatible. A finite element solution was done using hardening material model to verify the analytical results and metal flow and to examine the strain and stress fields in the product.

Purpose This paper aims to examine risk-taking in Islamic banks by exploring moral hazard and owner/manager agency problems simultaneously. Design/methodology/approach The authors propose to estimate a model of bank risk-taking that includes both franchise value and ownership structure as explanatory factors of bank risk. Findings The results show that franchise value is an important determinant of Islamic bank risk-taking. Banks with high franchise values are less likely to take risks than banks with low franchise value. In contrast, outside block holders have, at best, limited influences on bank risk-taking. Originality/value This paper conducts the first empirical examination of the relationship between managerial risk preferences and Islamic banks ownership. The authors examine simultaneously the effect of franchise value and owner/manager problem on Islamic bank risk taking behavior. They consider separately the impact on total risk, systematic risk and bank specific risk.

Purpose – The purpose of this paper is to examine the relationship between corporate governance (CG) and firms’ bond recovery rates (RRs). The authors hypothesize that governance features impact RRs by controlling agency costs that result from conflicts between bondholders and shareholders. The authors also test the relationship between CG and RRs during the last crisis. Design/methodology/approach – The authors use a generalized method of moments regression model to test the relationship between CG and firms’ bond RRs. The authors employ a direct measure of recoveries rates from Moody’s ultimate recovery database covering the period from 2003 to 2012. Both firm-level CG and country-level variables are used to examine the determinants of corporate bonds RRs. Findings – The results support a significant impact of CG mechanisms on bond RRs mainly during crisis period. The authors find that firms operating with CEO-Duality decrease their bond RRs during financial crisis. This implies wealth transfers from bondholders to shareholders and provides one explanation why some firms operate with weak governance. Originality/value – This paper provides the first direct evidence that corporate bond RRs are directly related to CG mechanisms. The authors combine firm-level CG and country-level variables to examine the determinants of corporate bonds RRs. Earlier studies focussed on financial firm-level data and macro-economic variables. The authors also test the impact of board composition and ownership structure on bond recoveries.

Dye mass balance study at full-scale industrial textile wastewater (ITW) treatment plant showed that 1.5 ton of excess waste sludge, containing 304.5 Kg of dyes, are daily produced and discharged in landfills. Therefore, this by-product of activated sludge process (ASP) presents a serious environmental problem. In this work, a laboratory and pilot scale investigations were carried out to optimize aerobic biodegradation efficiency to reduce the amount of residual adsorbed dye that will be found in the waste sludge. The resistance of acclimated biomass to the toxicity of ITW was studied in 2.5 L batch reactors using different dye to biomass (D/B) ratios of 0.102, 0.25 and 0.72 g CODS/g VSS. Results of respirometric analyses showed that acclimated activated sludge (AS) biomass is able to treat ITW at high D/B ratio of 0.72 g CODS/g VSS. Moreover, biodegradation kinetic study using Monod law showed that COD and color removal were better for the highest D/B ratio. The half saturation coefficient of heterotrophs for indigo dye (KSind) of 20.01 g/m3 showed high affinity between biomass and dye molecules. Optimization of the process at pilot-scale with different hydraulic retention time (HRT) of 2–5 days, and different sludge recycling rates (SRR) of 220–680 m3/d, showed that high HRT of 5 days and a SRR of 0.22 allowed the best dye biodegradation efficiency (95%). Application of the best conditions at full-scale reduced significantly (89%) the amount of the discharged dyes from 304.5 Kg/d to 33 Kg/d. Results were numerically validated using a mathematical model based on the activated sludge model 1 (ASM1).

boughattas, wissal/0000-0002-6495-743X; Asci, Hulya/0000-0002-6650-6931 WOS: 000424051900005 The study examined the cross-cultural validity of the short form of the Physical Self-Inventory (PSI-S) among samples of adolescents speaking French, Dutch, Turkish, Italian, and Arab. A total of 4,867 adolescents (1,173 Belgian Flemish, 598 French, 1,222 Italian, 643 Turkish, 646 Kuwaiti, and 585 Tunisian) completed the original PSI-S version, and a revised version including a positively worded reformulation of the 3 negatively worded PSI-S items. The results supported the factor validity and reliability of revised PSI-S version across all cultural groups, and its superiority when compared to the original version. Compared with confirmatory factor analyses, relying on an exploratory structural equation modeling measurement model resulted in superior solution, and in more cleanly differentiated factors. PSI-S responses proved to be fully invariant across cultural groups, and presented no evidence of differential item functioning as a function of age, gender, body mass index (BMI), and sport involvement. However, the results revealed meaningful mean level differences as a function of gender, age, sport involvement, and BMI that were mostly consistent with the results from previous studies. Australian Research CouncilAustralian Research Council [DP140101559] Preparation of this article was supported in part by a grant from the Australian Research Council (DP140101559). This article was prepared in part while the first author was a visiting scholar at the Universita degli Studi di Cagliari (Italy). The authors want to thank Samar Feghali for significant help in the development of the Arab version of the PSI-S.

International audience; Excess sludge disposal during biological treatment of wastewater is subject to numerous constraints, including social, health and regulatory factors. To reduce the amount of excess sludge, coupled processes involving different biological technologies are currently under taken. This work presents a laboratory scale sequencing batch aerobic system included an anaerobic zone for biomass synchronization (SBAAS: sequencing batch aerobic anaerobic system). This system was adopted to reduce sludge production during abattoir wastewater (AW) treatment. The average chemical oxygen demand (COD) removal efficiency of 89% was obtained at a hydraulic retention time (HRT) and a sludge retention time (SRT) of 2 days and 1520 days, respectively. The comparison of SBAAS performances with a conventional sequencing batch activated sludge system (SBASS) found that the observed biomass production yield (Y obs) were in the ranges of 0.26 and 0.7g suspended solids g 1 COD removed, respectively. A significant reduction in the excess biomass production of 63% was observed by using the SBAAS. In fact, in the anaerobic zone microorganisms consume the intracellular stocks of energy by endogenous metabolism, which limits biosynthesis and accelerates sludge decay. The single strand conformation polymorphism (SSCP) method was used to study the dynamic and the diversity of bacterial communities. Results showed a significant change in the population structure by including the anaerobic stage in the process, and revealed clearly that the sludge production yield can be correlated with the bacterial communities present in the system.

En Tunisie, nous ne disposons pas de plan national de depistage des aneuploidies. Nous nous proposons de comparer pour une meme population deux methodes de depistage des aneuploidies, et de discuter de l'importance de la qualite des mesures de la clarte nucale lors de l'echographie du premier trimestre. Il s'agit d'une etude prospective realisee sur une periode de 18 mois. Nous avons compare les resultats du calcul de risque realise selon deux methodes. La premiere tenant compte uniquement de l'âge maternel et des marqueurs seriques, et la deuxieme integrant en plus la clarte nucale. 19% des 221 parturientes etaient âgees de plus de 38 ans. Le test de depistage selon la 1ere methode etait sensible pour le seul cas d'aneuploidie rencontre. La puissance de ce test etait de 60%. Le dosage des marqueurs seriques du deuxieme trimestre a permis le depistage des defauts de fermeture du tube neural avec une valeur statistiquement significative en termes de specificite (98,6%) et de valeur predictive negative (100%). La mediane des mesures de CN etait de 0,75 MoM pour l'âge gestationnel. Uniquement 17,6% des mesures etaient situees dans l'intervalle [0,9 -1,1] MoM. Nous n'avons pas objective de difference significative entre les deux methodes depistage en matiere de puissance. Cependant, en termes de faux positifs le test combine s'est avere plus interessant, son utilisation aurait pu nous eviter 18 prelevements invasifs. L'avenir immediat en Tunisie doit se diriger vers un depistage combine au premier trimestre. Cette strategie ne peut se faire qu'apres instauration d'un controle qualite des mesures a la fois biologiques et echographiques. Pan African Medical Journal 2016; 23