In this paper, we have the percussive rotational drilling regime that is determined by the combination of the rotational speed of the tool, the axial force applied on the rock the optimal values of these parameters d epend in particular on the type of tool and on the physico mechanical properties of the rocks to be felled. The aim of the research is to improve the operating regimes of percussive d rilling machines under the conditions of the Algerian limestone quarries (Hadjar soud quarry) and to obtain a better compromise between the technical and economic indices, in order to ensure a minimum cost price for a meter of drilled hole. The experimenta l results carried that this methodology, which consists of assuming that under the concrete conditions can find the combination of the setting parameters that ensure the best techno economic indices, as well as to carpenter the cost price for a meter of dr illed holes.
The conformal mapping (CM) mode is engaged for conformal antenna strategy using the geometric representation of the CM. For some conformal antennas (CAs) have the same shape, actuality able to segment a shared rough system, which is an essential improvement of this method in these CA optimizations (CAOs). Different parameters of CAs are optimized. The function reactions in this sample are selected as starlike distribution. The assessments of efficiency, gain and accuracy with the commercial software Mathematica 11.2 are prepared. The suggested method is mainly appropriate for CAO. Moreover, we formulate the energy operator in a 2D geometry, when the discharged field is detected over a semi-circumference in the far zone.
The purpose of this paper is to examine the non-zero distinct integral solutions of quinary biquadratic homogeneous diophantine equation x4 + y4 - (x + y)w3 = 14z2T2 in integers. In this paper, we present some different patterns of integral solutions to the above diophantine equation in five variables. Also, we obtain some properties as relations between solutions and special numbers.
What a genius, building a home for more than 10 centuries in the Sahara desert with all the necessary amenities to withstand a hyper-arid climate like that of Timimoun and Tiout. During our work missions during the period: 2000-2019 in the south-west of the Sahara, we were interested in the feeding of Timimoun ksours by the foggaras. This study shows that feeding ksar water remains an unresolved problem for the ksouriens of the Sahara. Two success stories in this area of water have been cited in this paper. These are the ksours of Timimoun which are fed by the foggaras. The ksar of Tiout was supplied with water by an ancestral dam. These are the two cases of the Sahara that have benefited from water with zero energy. These two examples demonstrate the ingenuity of the ksours population. If after ten centuries, the oasis have managed to master the architecture of the ksours, against the supply of ksar in water has shortcomings.
The objective of this study is to evaluate the phytochemical constituents and anticoagulant, and antibacterial activities of phenolic extracts obtained from flaxseed. The quantitative estimation of total phenols by the colorimetric method showed that both aqueous and methanolic extracts are low in these compounds. The evaluation of the antibacterial activity of polyphenols was carried out by the disc method by determining the minimum inhibitory concentration (MIC). The results showed that no antibacterial activity with polyphenols was observed; against the five bacteria tested.The anticoagulant activity of polyphenols was also evaluated in vitro using the cephaline-kaolin (TCK) and Quick time (TQ) tests. The coagulation times obtained on normal plasma indicate that they have moderate activity on both coagulation pathways.
The study of the antagonistic activity of eleven isolates of Trichoderma spp., against four isolates of Botrytis cinerea, collected from diseased tomato plants cultivated in greenhouses located on the Algiers coast and in the north-east of Sahara. The in vitro antagonism was compared to the fungicidal activity of "PROLEX", widely used by farmers against this phytopathogen in Algeria. The results revealed a complete inhibition of sporulation, germination, production and germination of sclerotia as well as morphological changes in vitro. A significant reduction on their pathogenicity and a strong inhibition of their sporulation were recorded in vivo. In conclusion, the Trichoderma spp. antagonists in particular, the "T4, T11, T8 and T10" isolates are therefore promising for the biocontrol of grey mould of tomato.
The inhibitive effect of N, N-Dimethylaniline (DMA) as corrosion inhibitor for zinc in 0.1, 0.3 and 0.5 M H2SO4 solutions has been investigated by using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results obtained reveal that inhibition efficiency (I.E.) increases with increase in concentration of inhibitors but decreases with increase in temperature. As inhibitor concentration increases corrosion rate decreases. The rate constant ‘k’ decreases while half-life ‘t½’ increases with the increase in concentration of inhibitor. DMA showed maximum I. E. of 93.51 % at 60 mM in 0.5 M H2SO4 acid at 301 K. The inhibition effect is discussed in view of DMA molecules adsorbed on the metal surface and it obeys Langmuir adsorption isotherm. Polarization curve indicates that inhibitor act as mixed type for zinc corrosion in sulphuric acid solutions.
Housing in Algeria is experiencing a multi-dimensional crisis: crisis in design (standardization of housing), construction, financing, management, etc., which has a negative impact on user comfort, poor housing quality and high energy consumption.This article focuses on the study of the impact of different thermal insulation str ategies on energy consumption (heating and cooling) of a residential building situated in semi arid climate (Constantine northeast of Algeria) using thermal dynamic simulation tool (TRNSYS 16)
A new proline based ligand was syn thesized by a convenient procedure. The ligand was characterized by 1 H NMR, 13 C NMR and IR spectroscopies. Copper (II) Schiff base complexes of 4 --{[2 --(methoxycarbonyl) pyrrolidin 1 yl] methyl} benzoic acid of this ligand were synthesized and characterized by the aforementioned spectroscopy techniques, i.e. 1 H NMR, 13 C NMR and IR. Moreover, its bactericidal activity was assessed through the determination of the minimum inhibitory concentration (MIC) values as well as the i nhibition zone diameter for gram po sitive bacteria, such as Staphylococcus aureus , and gram negative bacteria like Klebsiella pneumoniae, Citrobacter freundii, Salmonella typhi, Enterobacter cloacae (the two bacteria Citrobacter freundii and Salmonella typhi are very sensitive against this molecule unlike Enterobacter cloac ae bacteria which is resistant).
Bioactive substances are responsible for therapeutic properties of the plant in folk medicine. They have actions in the body that may promote good health. They are being studied in the prevention of disease. The present investigation is focused on screening of bioactive substances present in the various parts (leaves, stems, and grains) of Solanum nigrum. Qualitative tests for the presence of phytochemicals in different extracts using solvants with different polarity such as methanol, chloroform, petroleum ether and aqueous extracts. Phytochemical investigation indicated the presence of various groups of compouds including alkaloids, flavonoids, tannins, coumarins, sterols and triterpenoids, saponins. Solanum nigrum L. acts an important role in traditional medicine and represent natural source of biactives compounds.
This article deals with the numerical simulation of a two-dimensional instantaneous heat and mass transfer processes within a commonly used intermetallic compound (a.k.a. Mischmetal) packed in a unit disc of an annulus-disc reactors, during hydrogen gas desorption. Using the finite volumes technique bundled in the OpenFOAM® CFD code, temperature and amount of desorbed hydrogen and their time-averaged quantities inside the metal-hydride packed bed are obtained for various temperatures of fluids used in heat transfer, and several outlet pressure magnitudes. Using a set of numerical simulations, we have emphasized the impacts of both parameters on metal-hydride reactor performance related to discharging time. An excellent accord was recorded for the present simulations results compared against the literature-reported experimental data [20].
Sand plays a very important role during the manufacture of concrete and mortar for the need of civil engineering and building. It influences both the properties of cementary materials in the fresh state and in the hardened state. The objective of this work is the development of self-compacting mortars with the various sands existing in the region of the city of Mascara for the main study of mechanical performance. Six sands were used for this purpose: three natural sands and three crushed sands. The tests carried out during this research are: physical tests, tests in the fresh state and tests on hardened mortars. The results to which our research has led is that self-compacting mortars made with crushed sands give a granular skeleton with high compactness and superior mechanical performance compared to self-compacting mortars made with natural sands.
In this paper, we are interested in identifying the parameters of a bioreactor in the case of a nitrification process. To represent the uncertainties that affect these parameters, we fo cus on the set approach based on interval arithmetic, in particular set inversion, to obtain guaranteed results. First, a method of studying observability and identifiability by an algebraic method is carried out. The LSCR (Leave out Sign dominant Correlat ion Regions) method used in this article for the identification of parameters is based on the construction of non asymptotic confidence regions for the parameters of the dynamic system This method, using the calculation of the correlation functions, makes it possible to construct regions containing the real value of the parameters to be identified with a guaranteed probability and with a minimum knowledge of noise. For guaranteed results, set inversion has been associated with this approach.
This study was conducted to assess food safety knowledge, attitudes and practices among restaurant food handlers in North Lebanon and to determine what impact the food safety intervention had on the performance of workers. A structured questionnaire of 35 questions has been used to collect information on socio-demographic characteristics, knowledge, attitudes and practices for 110 food handlers randomly working in 38 food service establishments via face-to-face questioning interviews during three months. The intervention was made to a subgroup of 13 participants followed by a reassessment. The average percentage scores of all food handlers for knowledge, attitudes, and practices were 63.78%, 83.63% and 81%, respectively. For the 13 participants who received the intervention, a significant improvement was observed in their performance after the training (p ˂ 0.001).
Mechanical buckling response of isotropic and orthotropic plates using the two variable refined plate theory is presented in this paper. The theory takes account of transverse shear effects and parabolic distribution of the transverse shear strains through the thickness of the plate; hence it is unnecessary to use shear correction factors. Governing equations are derived from the principle of virtual displacements. The nonlinear strain-displacement of Von Karman relations are also taken into consideration. The closed-form solution of a simply supported rectangular plate subjected to in-plane loading has been obtained by using the Navier method. Numerical results are presented for the present efficient sinusoidal shear deformation theory, demonstrating its importance and accuracy in comparison to other theories.
The compound bisbenzothiazolium hexacholoridostannate(II) dihydrate was obtained and structurally characterized by single-crystal X-ray diffraction techniques. The ionic compound crystallizes in the triclinic, space group P-1. The environment of the Sn ion is octahedral slightly deformed. Supramolecular architecture involves C—H…O, C—H…Cl and N—H…O hydrogen bonds and featuring p–p stacking interactions link the molecules into a three-dimensional network. Hirshfeld analysis was performed to show the intermolecular interactions in the crystal structure.
Paper discusses the possibility of incorporation of date seed waste as fillers (DSF) into starch-g-PP matrices compared to kenaf fibers (KF with two lengths) based composites. Three starch-g-PP matrices (G906PF, G906PJ and G720PJ) were studied in parallel to a fully PP one. The investigated composites loaded to 20 wt.%, showed differences in performance related, principally, to loading type (DSF, KF) and matrix used. Results showed an improvement of tensile and impact stress at break as well as Shore D hardness of starch-g-PP composites reinforced with date seed fillers (DSF) or kenaf fibers (KF). Further, tensile, storage and loss moduli increased also with loading. Vicat softening point of either KF or DSF/starch-g-PP composites was greater with higher values for KF composites. However, thermal stability of starch-g-PP composites was better when DSF was used.
Morphological ampelography characteristics, technological, phenolic and tannic maturities were studied over four seasons (from 2009 to 2012) of Ahmeur Bouamer autochtonous Algerian variety. During the four harvests, Ahmeur Bouamer's cluster has showed a high quality of morphological parameters (weight, size, number of seeds/ berries per cluster).The weight was proportional to the size of the cluster which was moderately compact, thus avoiding the deformation and the bursting of the berries. As For the maturity index (MI), Ahmeur Bouamer grape recorded values ranging from 31.07 to 54.95 for the four seasons; values which would make it possible to consider that the harvest would be of excellent quality (when 30
This paper outlines an investigation into the effect of incorporating rolled aggregate powder as a cement replacement on mortar mechanical strength and resistance against sulfuric acid attack. The study examined compressive strength, and mass loss changes of mortars based on 10, 20 and 30% rolled aggregate powder replacement rates immersed in fresh water and 12 weeks in 5% sulfuric acid solutions. Experimental results showed improved compressive strength, with 10 and 20% rolled aggregate powder replacement rates and enhance mortar resistance to aggressive sulfuric acid attack.
A hydraulic jump is a characteristic phenomenon in open channel flow, downstream of block ramps or rock chutes a hydraulic jump can occur over a rough bed with great energy dissipation. This paper analyses the hydraulic jump that occurs in homogeneous rough minor beds in rectangular compound channels. the parameters that influence the length of the jump were systematically investigated [24]. the analyses of the phenomenon were conducted using the general jump equation. the experimental data were elaborated in order to supply a new formulation of the general jump equation that accounts for the minor bed roughness. New formulas that satisfactorily agree with the experimental data are proposed. The results showed that rough beds can be used to dissipate the excess hydraulic jump energy instilling basins.
