Search

Corrosion behavior of X65-type carbon steel exposed to 1M HCl aqueous solution was studied in the absence and presence of various concentrations of new synthesized 3-(4-chlorophenyl)-2-cyano-N-(4-hydroxyphenyl) acrylamide, abbreviated as (P2), and 6-amino-4-(4-chlorophenyl)-1-(4-hydroxyphenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile, abbreviated as (P3), at 25oC. Potentiodynamic polarization data indicated that the synthesized Cyanoacetamide derivatives suppress both anodic and cathodic reactions via adsorption on the carbon steel surface and blocking the active sites. The adsorption of the inhibitor molecules forms a protective film which decreases the surface heterogeneity. Electrochemical impedance spectroscopy (EIS) measurements reveal that as the inhibitor concentration is increased, both the inhibition efficiency (η%) and the charge transfer resistance (Rt) are increased while the electrochemical double layer capacity (Cdl) is decreased. The experimental impedance data were analyzed according to a proposed equivalent circuit model for the electrode/electrolyte interface. Chemical descriptors are calculated through the density functional theory (DFT), also adsorption of inhibitors on the metal surface investigated through Monte Carlo simulation. The mechanism of corrosion inhibition was discussed given the obtained results of surface analysis and the molecular structure of the additive obtained from quantum chemical calculations. Keywords:Corrosion inhibition; Polarization; Electrochemical impedance spectroscopy (EIS); Surface analysis; Quantum chemical calculations

The durability of shell and tube heat exchanger working in rich chloride containing formation water was maximized by providing high immunity towards pitting corrosion. Two new cationic surfactants namely OD20 and OD50 were synthesized from oleic acid derivative to evaluate their performance as pitting corrosion inhibitors for API 5L X 60 type carbon steel alloy. Pitting corrosion technique was executed to evaluate the pitting inhibition performance against pitting attack by studying the anodic cyclic polarization diagram obtained for each synthesized inhibitor. 95.9% inhibition efficiency against pitting growth was reported for OD20 while 89% was measured for OD50. Potentiodynamic polarization measurements and electrochemical impedance spectroscopy were conducted to study the performance of the synthesized inhibitors against uniform type corrosion. High inhibition efficiency against uniform type corrosion was reported for both of the synthesized inhibitors at 92.2% for OD20 and 95.7% for OD50. The obtained electrochemical results were confirmed by investigation of the surface morphology of carbon steel alloy by scanning electron microscope (SEM).

Exposure to 2,3,7,8-tetrachlorodibenzo-P-dioxin (TCDD) as an environmental pollutant caused hepatotoxicity and tumor promotion. Recently researchers pay an attention to the power of green tea (GT) and curcumin (CUR) as natural antioxidants against cellular damage. The present study was designed to evaluate the protective role of GT and CUR against TCDD-induced hepatotoxicity in mice. Fifty adult male mice were divided into 5 groups as follows: G1; control received vehicles, G2: treated with oral dose of TCDD (1.332 mg/kg bw) and left as positive control, G3, G4 and G5 were treated with GT (0.5 mg/kg bw), CUR (0.5 m /kg bw), and the combination of GT and CUR (1 mg/kg bw) 30 minutes before injection with oral dose of TCDD (1.332 mg/kg bw), respectively. After 30 days of daily treatment with the antioxidants and TCDD mice were killed for collection of liver. Histological studies using light and electron microscopy were done in addition to the estimation of antioxidants parameters; catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH). Microscopically observations showed necrosis, inflammatory reactions, increased collagen, decreased polysaccharides and protein contents, and reduction in the antioxidants in the liver of mice treated with TCDD. However, the liver of mice treated with GT, CUR, and the combination showed improvement in the histological structure of the liver with enhancement in the antioxidants levels with the priority for the GT. In conclusion, TCDD induced histological and biochemical changes in the hepatic tissue and the ability of GT and/or CUR to prevent these changes was due to their activity as powerful antioxidants.

Grain yield and its components of 14 hull-less barley genotypes were evaluated in two seasons (2013/2014 and2014/2015) in five locations (Nubaria, Sakha, Gimmeza, Quntra sharq and Giza) in Egypt. Grain yield ranged from 3.96to 6.56 t/ha for “L6” and “L3” promising lines. respectively, with grand average of 5.11 t/ha. Giza 135, Giza 136 cultivarL3and L2 promising line produced highest grain yield and its components. On the other hand, the least genotype “L6” ingrain yield was had least values in most yield and its components.Pooled analysis of variance revealed significant effect of S x L interaction and the seasons had greater effect thanlocation, Results also showed significant G x S x L interaction, this means there were differences in relative performanceof genotypes over season-location combinations or in other word there were changes genotype x location effect amongseasons.According to stability parameters (bi, S2d, R2, C.V %) and yield average results revealed that L2, L3, L6 promisinglines and Giza 135 and Giza 136 showed average stability with general adaptability. However, L8, Giza 129 and Giza 131were adapted to high yielding environments. On the other side, L4, L5 and L7 promising lines are adapted to low yieldingenvironments.

Five new synthesized non ionic surfactants (I–V) were synthesized and characterized using FTIR and NMR spectroscopic methods. Performance of the synthesized compounds as corrosion inhibitors for X- 65 type carbon steel in oil wells formation water was investigated by various techniques such as weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). It was found that the percentage inhibition efficiency (η%) increases by increasing the inhibitor concentration until the critical micelle concentration (CMC) is reached. Also, the results showed enhancement in inhibition efficiencies with increasing both molecular size of the surfactant and the degree of ethoxylation. Potentiodynamic polarization curves indicated that the inhibitors under investigation act as mixed type. The data obtained from electrochemical impedance spectroscopy (EIS) were analyzed to model the corrosion inhibition process through equivalent circuit. Finally, the nature of the protective film formed on carbon steel surface was analyzed by SEM and EDX techniques.

Micronutrients in food have been found to have chemopreventive effects, supporting the conclusions from epidemiologie studies that consumption of fresh fruits and vegetables reduces cancer risk. The present study was carried out to evaluate the role of querctin (Q) and sodium gluconate (GNA) supplementation separately or in combination in ameliorating promotion of colon tumor development by dimethyl-hydrazine (DMH) in mice. Histopathological observation of colons in mice treated with DMH showed goblet cell dysplasia with inflammatory cell infiltration. This pathological finding was associated with significant alteration in oxidative stress markers in colon tissues and carcinoembryonic antigen (CEA) levels in plasma. Mice co-treated with GNA and Q showed mild changes of absorptive and goblet cells and inflammatory cell infiltration in lamina properia, with improvement in oxidative stress markers. In conclusion, findings of the present study indicate significant roles for reactive oxygen species (ROS) in pathogenesis of DMH-induced colon toxicity and initiation of colon cancer. Also, they suggest that Q, GNA or the combination of both have a positive beneficial effect against DMH induced colonic cancer induction in mice.

Heat transfer characteristics to both laminar and turbulent pulsating pipe flows under different conditions of Reynolds number, pulsation frequency, pulsator location and tube diameter were experimentally investigated. The tube wall of uniform heat flux condition was considered for both cases. Reynolds number varied from 750 to 12,320 while the frequency of pulsation ranged from 1 to 10 Hz. With locating the pulsator upstream of the inlet of the test section tube, results showed an increase in heat transfer rate due to pulsation by as much as 30% with flow Reynolds number of 1,643 and pulsation frequency of 1 Hz, depending on the upstream location of the pulsator valve. Closer the valve to the tested section inlet, the better improvement in the heat transfer coefficient is achieved. Upon comparing the heat transfer results of the upstream and the downstream pulsation, at Reynolds number of 1,366 and 1,643, low values of the relative mean Nusselt number were obtained with the upstream pulsation. Comparing the heat transfer results of the two studied test sections tubes for Reynolds number range from 8,000 to 12,000 and pulsation frequency range from 1.0 to 10 Hz showed that more improvement in heat transfer rate was observed with a larger tube diameter. For Reynolds number ranging from 8,000 to 12,000 and pulsation frequency of 10 Hz, an improvement in the relative mean Nusselt number of about 50% was obtained at Reynolds number of 8,000 for the large test section diameter of 50 mm. While, for the small test section diameter of 15 mm, at same conditions of Reynolds number and frequency, a reduction in the relative mean Nusselt number of up to 10% was obtained.

Heat transfer characteristics to turbulent pulsating pipe flows under a wide range of Reynolds number and pulsation frequency were experimentally investigated under uniform heat flux condition. Reynolds number was varied from 8462 to 48540 while the frequency of pulsation ranged from 1 to 29.5 Hz. The results showed that the relative mean Nusselt number is strongly affected by both pulsation frequency and Reynolds number. Enhancements in mean Nusselt number of up to 50% were obtained at medium pulsation frequency between 4.1 and 13.9 Hz for Reynolds number range of 8462 to 14581. An enhancement of up to 50% in mean Nusselt number was obtained at high pulsation frequency range between 13.9 and 29.5 Hz, specially as Reynolds number is close to 15000, while a reduction was observed at higher Reynolds number more than 21200. This reduction, at high Reynolds number, increased as pulsation frequency increased. Also, there was a reduction in mean Nusselt number of up to 20% that obtained at low pulsation frequency range between 1 and 4.1 Hz for Reynolds number range of 8462 to 48543. A significant reduction in mean Nusselt number of up to 40% was obtained at medium pulsation frequency between 4.1 and 13.9 Hz for Reynolds number range of 21208 to 48543. Empirical equations have been developed for the relative mean Nusselt number that related to Reynolds number and dimensionless frequency with about uncertainty of 10% rms.

Heat transfer characteristics to laminar pulsating pipe flow under different conditions of Reynolds number and pulsation frequency were experimentally investigated. The tube wall of uniform heat flux condition was considered. Reynolds number was varied from 780 to 1987 while the frequency of pulsation ranged from 1 to 29.5 Hz. The results showed that the relative mean Nusselt number is strongly affected by pulsation frequency while it is slightly affected by Reynolds number. The results showed enhancements in the relative mean Nusselt number. In the frequency range of 1–4 Hz, an enhancement up to 30% (at Reynolds number of 1366 and pulsation frequency of 1.4 Hz) was obtained. In the frequency range of 17–25 Hz, an enhancement up to 9% (at Reynolds number of 1366 and pulsation frequency of 17.5 Hz) was indicated. The rate of enhancement of the relative mean Nusselt number decreased as pulsation frequency increased or as Reynolds number increased. A reduction in relative mean Nusselt number occurred outside these ranges of pulsation frequencies. A reduction in relative mean Nusselt number up to 40% for pulsation frequency range of 4.1–17 Hz and a reduction up to 20% for pulsation frequency range of 25–29.5 Hz for Reynolds numbers range of 780–1987 were considered. This reduction is directly proportional to the pulsation frequency. Empirical dimensionless equations have been developed for the relative mean Nusselt number that related to Reynolds number (750 < Re < 2000) and the dimensionless frequency (3

Electronic absorption and fluorescence spectra of anthracene-9-carboxylic acid (ANCA) were studied in different homogeneous solvents, binary protic/aprotic solvent mixtures and in heterogeneous solutions of the cationic cetyltrimethyl ammonium bromide (CTAB) micelle. Different chemical species of ANCA were identified spectroscopically in different media. The results are discussed on the basis of a mechanism that involves two equilibria: acid-base equilibrium and monomer-dimer equilibrium. These equilibria were found to be very sensitive to the nature of the medium and the concentration of ANCA.Moreover, while it is photostable in most solvents studied, the ANCA was found to be photolabile in aqueous media of different pHs. The acid-base catalyzed photodegradation rate was studied by following up absorption and/or fluorescence intensities as a function of illumination dose. The determined rate of the photochemical degradation of ANCA depends on the nature of the medium. The first order degradation rate constant is remarkably enhanced in heterogeneous medium of CTAB. As expected, the determined activation energy is low (∼3.2 kJ.mol-1). This result favors photooxidation process. Anthraquinone was the main photodegradation product obtainedvia9,9′-dicarboxylic head-to-head dimer of anthracene that was identified by GC-Mass technique.

Kharga Oasis is the southernmost of five oases in the Western Desert of Egypt. The Oasis bears potential Nubian Sandstone Aquifer, which considered being the most bearing underground reservoir at Egypt. Agricultural and population development of this region suggests the importance of the evaluation of its water storage capacity. Satellite spatial and temporal gravity data have opened new perspectives on the Earth sciences and hydrological studies. The two sets of the satellite data have been utilized to study configuration and temporal water recharge capacity of underground basin reservoirs. The study shows set of faulting led to a complicated configuration of the underground sand basin. In addition, Monthly data from GRACE estimate the irregularities of the water income. Finally, the study pointed out the potentiality of using satellite spatial and temporal gravity data to study configuration and temporal water recharge capacity of underground basin reservoirs.

We investigate the enhancement of heat transfer and the consequent conservation of energy in channels with segmented baffles. The influence of Reynolds number, baffle spacing, baffle material, and heat flux on local and average heat-transfer coefficients have been studied. Our results show that the flow must pass over three to six baffles before it becomes periodic and fully-developed. Augmentation of heat transfer was obtained with increases in Reynolds number, thermal conductivity of the baffles and decreases in baffle spacing and wall heat flux.

Measurements of mean temperature, concentrations of unburned hydrocarbon, carbon monoxide, carbon dioxide and oxygen and of velocity have been obtained in a series of confined kerosene-spray flames. They quantify the influence of mean droplet diameter in the range from 54 to 115 μm, of swirl number in the range from 0.47 to 1.4 and of combustion air temperature in the range from 20 to 225°C. Four flame configurations are identified and correspond to: high swirl, high temperatures and small droplets with consequent droplet evaporation in the recirculation region; larger droplets which penetrate the recirculation region and result in combustion close to the combustor wall; intermediate swirl so that droplets of all sizes penetrate the recirculation region and move upstream and downstream to burn; and weak swirl where the flame is stabilized close to the wall and the main flame extends further downstream. Calculated results are also reported and allow the magnitude of associated uncertainties to be ...