Synthesize of green silver nanoparticles by one pot microwave-assisted technique: Modeling and optimization

The use of nanoparticles (NPs) is recently increased due to their many applications in many different sectors. The majority of the methods used to manufacture of nanoparticles is mostly harmful to the environment and have high costs. The aim of the current work is to step forward in production silver NPs in a way with less cost and harm to environment using the green biosynthesis route. The Silver NPS colloidal suspension is produced based on the reaction of the metal precursor AgNO3 and a Cactus extract using Microwave instead of thermal heating. Optimization and modeling of NPs synthesis at lab scale is carried out throughout 10 experiments designed using software for experimental design and treating the responses statistically. The effect of concentration the metal precursor and power of microwave on the formation time of the NPs is investigated using Response Surface Methodology. The statistical results showed that the microwave power is more significant than the metal ions concentration, and the Ag NPs formation time decreased with increasing the microwave power and metal ions concentration. The optimum value for NPs formation time estimated is 10.27 minute. This formation time could be achieved using microwave power of 129.05 Watt and 1.8 ml of AgNO3 solution. The equilibrium adsorption data of methylene blue dye on the synthesized silver NPs were mathematically modeled by employing the pseudo-first-order kinetics equation and the photo-catalytic performance was inspected throughout the degradation of methylene blue under irradiation by sunlight. The dye was effectively nearly 99% degraded by the green synthesized silver nanoparticles after 72 hours of exposure to sunlight

DIC TEXTURING-ASSISTED ACCELERATED SOLVENT EXTRACTION OF ACTIVE MOLECULES OF POMEGRANATE PEEL

The current work discusses the use of Instant Controlled Pressure Drop (DIC) as a pretreatment texturing stage intensifying phenolic compound extraction from South Tunisian Punicagranatum L. peels in both cases of conventional and Accelerated Solvent Extraction (ASE). Response Surface Methodology (RSM) allowed identifying the effects of DIC processing parameters on the yields of Total Phenol Compounds (TPC), Total Flavonoid (TF), Condensed Tannins (CT), and Hydrolysable Tannins (HT), and antioxidant capacities via 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity and ß-carotene-linoleic acid as responses. Comparative methods were used to evaluate DIC-textured and Raw samples. The results obtained confirmed that appropriate DIC-texturing improved both kinetic and yield of bioactive compound extraction using ASE from Punicagranatum L. peels. Extraction kinetics was studied through Coupled Washing-Diffusion CWD model. The effective diffusivity was identified and quantified ranged from 0.27 to 8.22 against 0.4710-10 m2s-1 for DIC textured and raw material (RM), respectively. DIC swelling enabled solid vegetal material matrix to expand and be more adapted to mass transfer thus increasing extractability of the phenol compounds. Scanning Electron Microscope SEM showed that DIC generated pores with an average diameter of 50 µm

Optimization and Modeling the Processes of Green Magnetite Nanoparticle: Synthesis, Photo Catalysis Tendency and Kinetics of Removing Organic Dye from Aqueous Solutions

Green magnetite nanoparticles (NPs) are synthesized, characterized and employed for degradation Methylene Blue (MB) from aqueous solutions. The effect of the concentrations of the NPs and MB on NPs yield and removal efficiency is optimized and modeled using two factorial central composite experimental design. The analysis of variance confirmed that the concentration of iron metal salts seemed more significant than plant extract. The developed mathematical model is estimated with high R2 reflecting its accuracy. The results proved that the removal efficiency of MB increases up to an optimum of 82.07 % when using 0.17 g of the nano photo catalyst versus 10.8 ppm of MB with sunlight irradiation time of 200 min. The dye degradation kinetic results revealed that photo catalytic degradation follow pseudo-first-order model. Response Surface Methodology proved as an efficient tool for optimization and modeling the processes of NPs production and removing of organic pollutants from aqueous solutions

The role of the annual plan for the management of human resources in activating the performance of the human resource in institutions and public administrations ) case study of the municipality of Ain Romana, state of Blida)

تهدف هذه الورقة البحثية إلى دراسة المخطط السنوي لتسيير الموارد البشرية في المؤسسات والإدارات العمومية وذلك بتجسيد التنبؤات المتعلقة بالموارد البشرية خلال فترة مستقبلية، وإبراز دوره في تفعيل أداء هذا المورد البشري، من خلال عمليات التوظيف، الترقية والتكوين التي يتضمنها هذا المخطط، حيث أن عملية الترقية تفتح باب المنافسة أمام الموظفين لإبراز قدراتهم ومهاراتهم، أما التكوين يهدف إلى تنمية كفاءة الموظفين، والتوظيف يعمل على اختيار أفضل الأفراد ذوي كفاءة؛ وعليه قمنا بدراسة حالة المخطط السنوي لتسيير الموارد البشرية لبلدية عين الرمانة ولاية البليدة، بغرض الوصول إلى نتائج تفيد دراستنا في هذا الموضوع.This research paper aims to study the annual plan for the management of human resources in institutions and public administrations by reflecting human resources forecasts during a future period, and highlighting its role in activating the performance of this human resource, through the recruitment, promotion and training processes that Included in this scheme, as the promotion process opens the door to competition for employees to showcase their abilities and skills, the training is aimed at developing staff competency, and recruitment works to select the best qualified individuals; and so we studied the status of the annual plan for the management of the human resources of the municipality of Ain Romana state of Blida, for the purpose of reaching the results of our study on the subject

IMPACT OF INSTANTANEOUS CONTROLLED PRESSURE PROP (DIC) TECHNOLOGY ON EXTRACTION OF TOTAL PHENOLS OF MOROCCAN SALVIA OFFICINALIS

The main objective of this study was to intensify the extraction of total phenols from Salvia officinalis L. using instant controlled pressure drop (DIC) as a texturing pre-treatment. The effect of solvent type on Total Phenolic Content (TPC) was also studied. TPC was determined using spectrophotometric Folin-Ciocalteau method and external calibration with Gallic acid. The obtained results showed that water was the most efficient solvent to extract total phenols from Salvia officinalis L. Moreover, texturing and expansion by DIC pretreatment had a great impact on polyphenol yields and revealed greater extraction kinetics. Likewise, drying kinetics of DIC-treated sage was enhanced compared to the raw material. DIC-assisted extraction can be considered as a promising technology to use in the case of the Moroccan Salvia officinalis L. as an important Mediterranean source of natural phenols

Simultaneous removal of chromotrope 2B and radionuclides from mixed radioactive process wastewater using organo-bentonite

The simultaneous removal of cationic radionuclides, 137Cs(I), 60Co(II) and 152+154Eu(III), and a chemically toxic anionic pollutant, the analytical reagent chromotrope 2B (C2B), from simulated mixed radioactive process wastewater (MRPWW) has been investigated using bentonite modified with cetyltrimethylammonium bromide. Modification was confirmed by elemental analysis, X-ray diffraction and infrared spectroscopy. Bentonite partially modified to 78% of the cation exchange capacity (PMB) was found capable to adsorb adequately both C2B and the radionuclides from aqueous solutions. Detailed batch kinetics and isotherm studies for removal of C2B singly and the radionuclides simultaneously were performed. The C2B and radionuclides kinetics conform to pseudo-first-order rate equation and the adsorption isotherms are treated with Freundlich and Langmuir models. Thermodynamic parameters were evaluated. Results suggest physisorption and ion-exchange as the principal uptake mechanism for C2B and the radionuclides, respectively. High simultaneous removal was obtained for C2B (≈ 100%) and each of the test radionuclides (>99%) from the simulated MRPWW

An electrochemical sensor based on carboxymethylated dextran modified gold surface for ochratoxin A analysis

A disposable electrochemical immunosensor method was developed for ochratoxin A analysis to be applied for wine samples by using a screen-printed gold working electrode with carbon counter and silver/silver chloride pseudo-reference electrode. An indirect competitive enzyme-linked immunosorbent assay (ELISA) format was constructed by immobilising ochratoxin A conjugate using passive adsorption or covalent immobilisation via amine coupling to a carboxymethylated dextran (CMD) hydrogel on the gold working electrode. Electrochemical detection was performed using 3,3′,5,5′-tetramethylbenzidine dihyrochloride (TMB) and hydrogen peroxide with horse radish peroxidase (HRP) as the enzyme label. Chronoamperometry at -150mV vs. onboard screen-printed Ag-AgCl pseudo-reference electrode was then used to detect the generated signal. The performance of the assay and the sensor was optimised and characterised in pure buffer conditions before applying to wine samples. The resulting immunosensor for ochratoxin A in buffer achieved a limit of detection of 0.5μgL-1 with a linear dynamic detection range of 0.1-10μgL-1 for passive adsorption of the toxin conjugate. While for covalent immobilisation through CMD-modified gold electrode, a limit of detection of 0.05μgL-1 was achieved with a linear dynamic detection range of 0.01-100μgL-1. The CMD-modified gold immunosensor was then evaluated in spiked and affinity purified wine samples achieving a detection limit comparable to buffer solutions (0.05μgL

Enhancing Concrete Properties Using Silica Fume: Optimized Mix Design

In the current work, concrete mixes containing (7.0-33.11) weight % silica fume as a partial replacement of cement with a water /cement ratio (0.42-0.48) were prepared according to an adopted two factorial central composite design. The samples were tested, optimized, and modeled for compressive strength and density.  The estimated results confirmed that compressive strength and density increase with increasing silica fume content up to 11.9 wt.%. Response surface analysis results confirmed that silica fume concrete with developed compressive strength (53.42 MPa) could be prepared by incorporation of 11.9 wt. % silica fume as partial replacement of cement using 0.42 water/cement ratio. An increase in compressive strength and density (up to  39.3% and  2.6% ) respectively was recorded for silica fume concrete mixes compared to Portland cement concrete. Overall, the research findings revealed that silica fume concretes prepared with appropriate silica fume content and water/cement ratio exhibited superior strength and density characteristics candidate them to be used effectively in civil engineering applications

Adopted Factorial and New In-Situ Micro-Designs for Stimulation of Matrix Acidizing of Carbonate Reservoir Rocks

Matrix acidizing has been developed in the petroleum industry for improving petroleum well productivity and minimizing near-wellbore damage. Mud acid (HF: HCl) has gained attractiveness in improving the porosity and permeability of reservoir formation. However, there are several challenges facing the use of mud acid, comprising its corrosive nature, high pH value, formation of precipitates, high reaction rate and quick consumption. Therefore, different acids have been developed to solve these problems, including organic-HF or HCl acids. Some of these acid combinations proved their effectiveness in being alternatives to mud acid in reservoir rock acidizing. The current research deals with a new acid combination based on Hydrochloric–Oxalic acids for acidizing carbonate core samples recovered from Qamchuqa Formation in Kirkuk oilfield, northern Iraq. A new in-situ micro-model adopted laboratory technique is utilized to study the microscale alteration and evolution of pore spaces, dissolved grains and identification of matrix acidizing characteristics. The in-situ micro-model is based on the injection of an identical dose of different concentrations of the new acid combination into thin section samples under an optical light microscope. The adopted procedure aims to provide unique and rapid information regarding the potential for texture and porosity modification that can be caused by the acidizing stimulation procedure. In connection, solubility tests for the untreated and treated reservoir core samples and the density of the combined acids after treatment are conducted based on designed experiments using response surface methodology (RSM). The effect of acid concentration [12% HCl: Oxalic acid (3.8–8.8%)] and acidizing temperature (from ambient to 78.8 °C) on the solubility percentage of the samples and percentage increase in the combined acid density after acidizing were optimized and modeled. The obtained results confirm that the optimum dissolution of the core samples took place using 12% HCl:3.2% Oxalic acid with an optimum solubility (%) of the carbonate core rock of 53.78% at 21.7 °C, while the optimum increase in density (%) of the combined acids was 1.54% at 78.3 °C. The promising results could be employed for matrix acidizing of carbonate reservoir rocks for other oilfields

Aqueous drilling fluids systems incorporated with green nanoparticles and industrial spent caustic: Optimum rheology and filtration loss properties

Drilling fluids are one of the most significant components of drilling operations for proper functions including fluid loss reduction into the formation and outstanding rheological properties. The drilling fluids according to environmental regulations and governmental rules have to be friendly to the environment to lessen the negative effects on the environment and improve safety. In the current study, a cost-effective industrial alkali waste (spent caustic) was used as a pH controller along with the environmentally friendly uncoated and Chitosan-coated green magnetite nanoparticles (MNPs) in water-based drilling fluid systems. The study focuses on exploring the impact of the alkali waste compared to the conventional alkali (NaOH) on rheology and filtration loss properties. The flow models of the drilling fluid systems were examined. The results proved that the drilling fluid formulated with polymer-coated green MNPs and waste alkali exhibited higher rheological properties and lower mud cake thickness and filtration volume compared to the reference fluid, thus, the waste alkali could replace NaOH as a pH controller. The flow behavior of new fluids could be described precisely using the Herschel-Bulkley flow model. Whereas, the Bingham plastic flow model described the fluid systems incorporated with uncoated and polymer-coated green NPs and NaOH