Assessment of the effect of modern transformation on the traditional settlement ‘Ksar’ of Ouargla in southern Algeria

The architecture of the Ouargla Ksar has long been recognized as an example of adaptation to harsh climate in the deep desert of Algeria. Over the last few decades, it has undergone some changes in its initial urban structure, due to accelerated and uncontrolled modern urbanization, that had negative implications and devaluation of its thermal characteristics. This article tries to understand the bioclimatic concept of adaptation of this Ksar and assess to what extent its morphological transformation has impacted its microclimatic conditions. This assessment is made through a comparative study between two different areas: one untransformed and the other transformed. A referential weather station situated in the suburbs was also exploited for consolidation of comparison. The investigation was undertaken using site measurements and observations.     

Removal of Basic Red 46 dye from aqueous solution by adsorption and photocatalysis: equilibrium,isotherms, kinetics,and thermodynamic studies

ABSTRACT

In this study, the main objective is the elimination of Basic Red 46 dye by coupling two processes, adsorption on activated clay followed by photocatalysis over ZnO as photocatalyst. The adsorption was investigated under different conditions of pH, adsorbent dose, dye concentrations, and temperature. The best adsorption yield occurs at neutral pH ~ 7 within 60 min with an uptake percentage of 97% for a concentration of 25 mg/L and a dose of 0.5 g/L. The results at equilibrium were successfully described by the Langmuir model with an adsorption capacity of 175 mg/g. To investigate the mechanism of dye adsorption characteristic, the adsorption constants were determined using pseudo first order, pseudo second-order and intraparticle diffusion model. It was found that the Basic Red 46 dye adsorption is well described by the pseudo second-order kinetic. The second part of this work was dedicated to the photodegradation onto ZnO under solar irradiation of the residual BR 46 concentration, remained after adsorption. For the remaining concentrations, the removal yields reach 100% under.     

Computing Shear Flow and Sludge Blanket in Secondary Clarifiers

Recent developments in computing turbulent and buoyant flow in sedimentation tanks are introduced. The test case is a circular, center-feed secondary clarifier with inclined bottom and central sludge withdrawal. Axisymmetry is assumed, and the flow and settling processes are modeled in a radial section by using the k-ε turbulence model on a two-dimensional, nonorthogonal grid. The computation domain includes the sludge blanket where the viscosity is affected by the rheological behavior of the sludge. The aim of the present study is to evaluate the sensitivity of the flow and concentration fields to parameters that characterize (1) the rheological properties of highly concentrated regions; (2) the settling of sludge; and (3) the effect of stratification on the turbulent diffusion. The overall appearance of the fields proves to be similar, whereas the regions of high velocities and high gradients are strongly affected by using different parameters or approaches on rheology, settling, and diffusive transport, resulting in different sludge blanket heights.     

Antioxidant and antibacterial effects of Lavandula and Mentha essential oils in minced beef inoculated with E. coli O157:H7 and S. aureus during storage at abuse refrigeration temperature

The essential oils (EOs) of Lavandula angustifolia L. and Mentha piperita L. were analyzed by gas chromatography mass spectrometry (GC/MS). The major constituents were linalool (22.35%), linalyl acetate (21.80%), trans-ocimene (6.16%) and 4-terpineol (5.19%) for L. angustifolia and menthol (33.28%), menthone (22.03%), and menthyl acetate (6.40%) for M. piperita. In vitro antibacterial activity of both EOs against Escherichia coli O157:H7 and Staphylococcus aureus CECT 4459 showed high inhibition against S. aureus. The lowest minimal inhibitory concentrations (MIC) were obtained with L. angustifolia (0.25μL/mL) against S. aureus; M. piperita exhibited a MIC of 0.50μL/mL against both microorganisms. Both EOs caused a significant decrease of bacterial growth in minced beef (p<0.05) stored at 9±1°C. Minced beef treated with EOs showed the lowest TBARS values (lipid oxidation). Moreover, the results showed that the addition of EOs significantly extended fresh meat odor even at abuse temperature.     

Experimental and theoretical study of Parabolic trough collector (PTC) with a flat glass cover in the region of algerian sahara (Ouargla)

Journal of Mechanical Science and Technology - In the present work, an experimental study has been performed at Ouargla in the south of Algeria to determinate the outlet water temperature and...     

Availability analysis of design configurations to compose virtual performance-optimized data center systems in next-generation cloud data centers

Next-generation cloud data centers are based on software-defined data center infrastructures that promote flexibility, automation, optimization, and scalability. The Redfish standard and the Intel Rack Scale Design technology enable software-defined infrastructure and disaggregate bare-metal compute, storage, and networking resources into virtual pools to dynamically compose resources and create virtual performance-optimized data centers (vPODs) tailored to workload-specific demands. This article proposes four chassis design configurations based on Distributed Management Task Force's Redfish industry standard applied to compose vPOD systems, namely, a fully shared design, partially shared homogeneous design, partially shared heterogeneous design, and not shared design; their main difference is based on the used hardware disaggregation level. Furthermore, we propose models that combine reliability block diagram and stochastic Petri net modeling approaches to represent the complexity of the relationship between the pool of disaggregated hardware resources and their power and cooling sources in a vPOD. These four proposed design configurations were analyzed and compared in terms of availability and component's sensitivity indexes by scaling their configurations considering different data center infrastructure. From the obtained results, we can state that, in general, when one increases the hardware disaggregation, availability is improved. However, after a given point, the availability level of the fully shared, partially shared homogeneous, and partially shared heterogeneous configurations remain almost equal, while the not shared configuration is still able to improve its availability.     

Modeling and assessing an intelligent system for safety in human-robot collaboration using deep and machine learning techniques

Multimedia Tools and Applications - The introduction of technological innovations is essential for accident mitigation in work environments. In a human-robot collaboration scenario, the current...     

A new enhanced assumed strain quadrilateral membrane element with drilling degree of freedom and modified shape functions

A new four‐node quadrilateral membrane finite element with drilling rotational degree of freedom based on the enhanced assumed strain formulation is presented. A simple formulation is achieved by five incompatible modes that are added to the Allman‐type interpolation. Furthermore, modified shape functions are used to improve the behaviour of distorted elements. Numerical results show that the proposed new element exhibits good numerical accuracy and improved performance, and in many cases, superior to existing elements. In particular, Poisson's locking in nearly incompressible elasticity fades and the element performs well when it becomes considerably distorted even when it takes almost triangular shape. Copyright © 2016 John Wiley & Sons, Ltd.     

DCAV: A software system to evaluate next-generation cloud data center availability through a friendly graphical interface

To assess the availability of different data center configurations, understand the main root causes of data center failures and represent its low-level details, such as subsystem's behavior and their interconnections, we have proposed, in previous works, a set of stochastic models to represent different data center architectures (considering three subsystems: power, cooling, and IT) based on the TIA-942 standard. In this paper, we propose the Data Center Availability (DCAV), a web-based software system to allow data center operators to evaluate the availability of their data center infrastructure through a friendly interface, without need of understanding the technical details of the stochastic models. DCAV offers an easy step-by-step interface to create and configure a data center model. The main goal of the DCAV system is to abstract low-level details and modeling complexities, becoming the data center availability analysis a simple and less time-consuming task.