Physiological and biochemical markers in the process of resistance and/or tolerance of heavy metals in the abandoned mining area of Sidi Kamber,Skikda, Algeria

This paper reports the biomonitoring of metallic pollution in the mine of Sidi Kamber Skikda town, to determine the resistance and/or tolerance to Zn, Pb, Cd and Cu in metalliferous plants. During the period of March–May, 2015, soil and plants samples were collected from three different stations in the study area. The total heavy metal fraction was determined by ICP/MS, whereas biochemical markers were determined by spectrophotometric techniques. The results obtained showed high levels of heavy metals in soil and plants compared to international standards. The translocation factor revealed that the studied plants can transfer and/or accumulate metals in their roots or their aerial parts as a function of characteristics of each metal, soil contents and physiological role in the plant. The contents of chlorophyll, proline, total sugars and total proteins are directly influenced by changes in bioavailable contents of heavy metals. It has been found that the plants studied and biomarkers are better suited for phytoremediation and biomonitoring of heavy metals pollution.     

Correction of pressure drop in a heavily loaded hybrid bearing when starting by using a constant flow lubrication system- Application to a rotary cement mill

We analyzed a lubricated journal plain bearing supporting heavy loaded rotary mill. During start-up operating, after the shaft is lifted by high external pressure lubricant, the speed of the shaft grows from 0 to the operating hydrodynamic speed when, suddenly after the first thirty seconds of shaft rotation, the pressure drops in one recess causing excessive damage to the pad bearing interface. The aim was to understand and provide some answers to the pressure drop in order to give an appropriate correction. Misalignment between the shaft and bearing surfaces was considered and analyzed in first part of the study. According to the obtained results the proposed correction is to use a suitable constant flow lubrication system which avoids the pressure to drop in recesses. A real application was made on a partial pad bearing supporting a heavy rotary cement mill localized at the cement plant of Chlef in Algeria.

     

An efficient artificial bee colony algorithm with application to nonlinear predictive control

In this paper a constrained nonlinear predictive control algorithm, that uses the artificial bee colony (ABC) algorithm to solve the optimization problem, is proposed. The main objective is to derive a simple and efficient control algorithm that can solve the nonlinear constrained optimization problem with minimal computational time. Indeed, a modified version, enhancing the exploring and the exploitation capabilities, of the ABC algorithm is proposed and used to design a nonlinear constrained predictive controller. This version allows addressing the premature and the slow convergence drawbacks of the standard ABC algorithm, using a modified search equation, a well-known organized distribution mechanism for the initial population and a new equation for the limit parameter. A convergence statistical analysis of the proposed algorithm, using some well-known benchmark functions is presented and compared with several other variants of the ABC algorithm. To demonstrate the efficiency of the proposed algorithm in solving engineering problems, the constrained nonlinear predictive control of the model of a Multi-Input Multi-Output industrial boiler is considered. The control performances of the proposed ABC algorithm-based controller are also compared to those obtained using some variants of the ABC algorithms.     

Adaptive Fourier Series Neural Network PID Controller

In this work, an Adaptive Neural Networks PID controller structure, called Adaptive Fourier Series Neural Networks PID controller (AFSNNPID), is developed. The main objective is to obtain a simple controller for nonlinear systems that can be tuned online to reject perturbations effect and compensate the system parameters variation. Due to its simple architecture and very attractive proprieties, the Fourier Series Neural Network (FSNN) is used to online adjust the parameters of the PID controller. Furthermore, using the delta-rule algorithm, the adaptation dynamics of the FSNN is globally stable. The design procedure of the proposed controller and the stability analysis of the closed loop system using the small gain theorem are given. To assess the effectiveness of the proposed control scheme, the control of a 3-DOF robot arm manipulator is considered and a comparative study, using the adaptive neural network PID controller and the particle swarm optimization based PID controller, is carried out. The obtained results, through the experimental study, indicate that the AFSNNPID controller presents better control performance than the other controllers.

     

Qualitative and Quantitative Evaluation of Quartz in Different Granular Types of Ouargla Region Sand Dunes – Algeria

In this paper, it is shown that Ouargla region (Algeria) sand dunes are very rich in quartz. This study aims to assess the quartz in the different granular sand types, using XRD spectroscopy. Granulometric classification and the size distribution curve were carried out. The X’Pert HighScore program based on the Rietveld refinement was used in analyzing the XRD data. Qualitative and quantitative quartz evaluations were carried out. It was deduced that the quartz was of the α phase. The concentrations of quartz have been calculated as: the very fine sand (0.063-0.100 mm) possessing the highest value of 82.05 %, followed by the coarse sand (0.500-1.000 mm) with 78 %, while in both the medium (0.250-0.500 mm) and the fine (0.100-0.250 mm) the concentration was about 67 %, whereas, the lowest one was 18.2 % in the very coarse sand (1-2 mm). These results were confirmed by FTIR spectroscopy. Crystallite sizes of quartz have been estimated, and their distribution curve versus grain sizes has been illustrated. It was found that the crystallite sizes in the fine sand are less than 100 nm, and thus may be considered as nanometric particles.     

Stress analysis in single molar tooth

The human tooth faces different stresses under environments of different loading conditions, these loading produces major factors in weakness of the tooth and bone structure. The need to save natural teeth has prompted the development of novel and complex techniques in endodontology, prosthodontics and periodontology. Despite a poor long-term prognosis and some prejudice to local bone, considerable efforts have been exerted for the realization of these techniques. Nowadays, the 3D finite element analysis (FEA) is one of the more recently used techniques for stress analysis in single human tooth under different loading cases. The von Mises stress distribution indicated that the greatest effort area of tooth lies at the base of crown up to the gingival line with varying intensities in the different loading cases. The highest stress in the cortical bone was predominantly found around the cervical region of the tooth and lowest in the cancellous bone and periodontal ligament (PDL). The PDL is a soft tissue, and it could function as an intermediate cushion element which absorbs the impact force and uniformly transfers the occlusal forces into the surrounding bone.     

A Structural and Electronic Properties DFT Study of BaFe2As2 and Two Derived Substitution Compounds

In this work, we calculated the structural and electronic properties of a pnictide iron based superconductor in both orthorhombic (Fmmm) and tetragonal (4I/mmm) phases using density functional theory in the generalized gradient approximation (GGA). We used pseudopotential and all-electron DFT variants. We found that the calculated structures are in good agreement with the experimental and other theoretical calculations. Two substitution compounds issued from the original compound were studied by the same methods.     

Antioxidant Activity of the Essential Oil and Oleoresin of Zingiber Officinale Roscoe as Affected by Chemical Environment

Three different biochemical test systems were chosen based on their solubility to study the antioxidant activity of ginger extracts. Reducing power and DPPH^. scavenging activity tests were considered to produce hydrophilic environments and the H₂O₂ test was considered as creating a lipophilic environment. The average yields were 10.23 ± 1.02% and 0.48 ± 0.19% for oleoresin and essential oil, respectively. The content of total phenols was 67.6 ± 1.08 mg GAE/g of dry extract. In terms of EC₅₀, in hydrophilic environment standards, it showed the highest effects compared to ginger extracts, with oleoresin presenting more activity than essential oil. In contrast, except for quercetin, essential oil showed the best scavenging activity in inhibiting H₂O₂ compared to all other antioxidants. The present work demonstrated that, when using reducing power, DPPH· free radical scavenging and H₂O₂ scavenging assays, the same ginger extracts exhibit different antioxidant activities, which were affected not only by the extract itself but also by the chemical environment (hydrophilic/lipophilic).