The kinetics of oxidation of methyl cellulose polysaccharide by acidic permanganate at a constant ionic strength of 2.0 mol dm−3 has been investigated, spectrophotometrically. Pseudo-first-order plots showed two distinct stages. The first stage was found to be relatively slow which corresponded to the formation of the substrate radical and Mn3+ or Mn4+ species as initial oxidation products, followed by an increase in the reaction rate at longer time periods. The reaction kinetics showed first-order dependence in permanganate and fractional second-order kinetics with respect to methyl cellulose concentration. The hydrogen ion dependence of the reaction rates indicated that the oxidation process is acid catalyzed. The induced polymerization of acrylonitrile indicated the intervention of free-radical mechanism. A kinetic evidence for the formation of 1:2 intermediate complex between the oxidant and the reductant, respectively, was revealed. The activation parameters have been evaluated, and a tentative reaction mechanism consistent with the kinetic results obtained is discussed.

Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 10 3 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H 2 O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A 2 model) and gas diffusion (D 4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, E a (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The E a− α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a …

Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 10 3 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H 2 O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A 2 model) and gas diffusion (D 4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, E a (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The E a− α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a …

Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 10 3 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H 2 O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A 2 model) and gas diffusion (D 4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, E a (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The E a− α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a …

Kinetics of dehydration of unirradiated and γ-ray irradiated neodymium (III) acetate hydrate with 10 3 kGy total γ-ray dose absorbed in air atmosphere were studied by isoconversional nonisothermal method. The dehydration proceeds in two steps with the elimination of 0.8 and 0.4 mol of H 2 O, respectively. This result indicates that the investigated neodymium (III) acetate hydrate contains 1.2 mol of crystalline water in its structure. The dehydration reactions are best described by nucleation (A 2 model) and gas diffusion (D 4 model) for unirradiated and γ-ray irradiated samples, respectively. Analysis of the kinetic data using linear and nonlinear isoconversional methods showed that the apparent activation energy, E a (kJ/mol) is dependent on the conversion degree, α, of the dehydration process. The E a− α plots for both unirradiated and γ-ray irradiated neodymium (III) acetate hydrate showed that the dehydration is a …

During the past decades, exploration activities carried out in the Western Desert of Egypt by several oil companies revealed the oversimplified approach to the study of sedimentary basins in this region. The current study evaluates and discusses the palynology and palynofacies of the clastic succession of the Kharita Formation (Albian) in one of the most petroliferous, deep seated, fault controlled basins in the Western Desert of Egypt, the Abu Gharadig Basin. Although the focus is on the palynofacies association, the hydrocarbon potential of the Kharita Formation will also be addressed by means of organic petrology and Rock-Eval pyrolysis. Marine Cretaceous source rocks have generated substantial quantities of oil and gas in the Abu Gharadig rift Basin. Moreover, Abu Gharadig Basin is characterized by containing not only oil/gas generating source rocks but also reservoir rocks with appreciable porosities and permeabilities. Palynological, TOC/Rock-Eval pyrolysis, and vitrinite reflectance (VRo%) data from 26 cuttings samples recovered from the Kharita Formation in the BED 2- 1× well, are presented. The palynological age dating (AL-2 Palynozone) confirmed early to middle Albian age based on the first downhole appearance of the marker Concavisimisporites punctatus. The optical and visual characterization of the palynofacies associations showed two distinct palynofacies associations that alternated with each other. Kerogen type III to III/II was recorded based on the dominance of phytoclasts and opaque organics. Some intervals showed a slight dominance of amorphous organic matter (AOM). Thermal Alteration Index (TAI) values of 2+/3-measured on the psilate trilete spores, in combination with vitrinite reflectance (VRo) values in the range from 0.51 to 0.62%, and the yellow to dull-yellow colors of the liptinite macerals exhibited under UV light excitation indicate immature to the early stage of the oil window. Tmax values from Rock-Eval pyrolysis range from 426 to 438 °C also confirm the low maturity of the organic matter. Thin coal stringers were recorded within the Kharita Formation having slightly higher VRo,ran values (0.64 to 0.76%), which is possibly the result of differences in mineral matrix variations within the Kharita Formation. Based on the low TOC (avg. 0.71 wt%), S2 (avg. 0.97 mg HC/g rock), and HI (avg. 149 mg HC/g TOC) values from pyrolysis, the hydrocarbon potential of the Kharita Formation in the studied well is considered to be low.

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Abstract In the present study two species were selected based on their highest presence values to study the response to the severe drought conditions in desert: these were Zilla spinosa and Leptadenia pyrotechnica. The results showed that soil water content and organic matter of Wadi El-Assiuty were very low over the study period. The estimated pH values in the soil solution at the different studied stands tended to be slight alkaline. Total soluble salts were generally higher during summer versus winter. The water content in the studied plants increased significantly during summer. The selected species increased their content of chlorophyll a and b in summer. The stability index of chlorophyll a and b was significantly higher in summer than that estimated in winter. Calcium and magnesium were accumulated in considerable amounts. Ca+2 was the main accumulated cation whereas its concentration were higher than magnesium. Z. spinosa accumulated more sulphates in summer than in winter. Phosphates appeared in low amounts in all the investigated plants. In L. pyrotechnica tissue, Na+ concentration correlated negatively with those found in soil during summer. In winter Na+ and SO4 correlated positively and K+ correlated negatively in Z. spinosa. The studied species showed slightly increase in soluble sugars accumulation. Soluble protein content in Z. spinosa and L. pyrotechnica decreased significantly during winter season. Amino acids content was low and varied between the two investigated species. It seemed that the Z. spinosa is better adapted than L. pyrotechnica to drought conditions, prevailing in the area under study. This judgement can be concluded by the average metabolic potentiality in the species, whereas soluble metabolites (soluble sugars and soluble proteins) were relatively much higher than in the case of L. pyrotechnica.

Abstract In the present study two species were selected based on their highest presence values to study the response to the severe drought conditions in desert: these were Zilla spinosa and Leptadenia pyrotechnica. The results showed that soil water content and organic matter of Wadi El-Assiuty were very low over the study period. The estimated pH values in the soil solution at the different studied stands tended to be slight alkaline. Total soluble salts were generally higher during summer versus winter. The water content in the studied plants increased significantly during summer. The selected species increased their content of chlorophyll a and b in summer. The stability index of chlorophyll a and b was significantly higher in summer than that estimated in winter. Calcium and magnesium were accumulated in considerable amounts. Ca+2 was the main accumulated cation whereas its concentration were higher than magnesium. Z. spinosa accumulated more sulphates in summer than in winter. Phosphates appeared in low amounts in all the investigated plants. In L. pyrotechnica tissue, Na+ concentration correlated negatively with those found in soil during summer. In winter Na+ and SO4 correlated positively and K+ correlated negatively in Z. spinosa. The studied species showed slightly increase in soluble sugars accumulation. Soluble protein content in Z. spinosa and L. pyrotechnica decreased significantly during winter season. Amino acids content was low and varied between the two investigated species. It seemed that the Z. spinosa is better adapted than L. pyrotechnica to drought conditions, prevailing in the area under study. This judgement can be concluded by the average metabolic potentiality in the species, whereas soluble metabolites (soluble sugars and soluble proteins) were relatively much higher than in the case of L. pyrotechnica.

Abstract In the present study two species were selected based on their highest presence values to study the response to the severe drought conditions in desert: these were Zilla spinosa and Leptadenia pyrotechnica. The results showed that soil water content and organic matter of Wadi El-Assiuty were very low over the study period. The estimated pH values in the soil solution at the different studied stands tended to be slight alkaline. Total soluble salts were generally higher during summer versus winter. The water content in the studied plants increased significantly during summer. The selected species increased their content of chlorophyll a and b in summer. The stability index of chlorophyll a and b was significantly higher in summer than that estimated in winter. Calcium and magnesium were accumulated in considerable amounts. Ca+2 was the main accumulated cation whereas its concentration were higher than magnesium. Z. spinosa accumulated more sulphates in summer than in winter. Phosphates appeared in low amounts in all the investigated plants. In L. pyrotechnica tissue, Na+ concentration correlated negatively with those found in soil during summer. In winter Na+ and SO4 correlated positively and K+ correlated negatively in Z. spinosa. The studied species showed slightly increase in soluble sugars accumulation. Soluble protein content in Z. spinosa and L. pyrotechnica decreased significantly during winter season. Amino acids content was low and varied between the two investigated species. It seemed that the Z. spinosa is better adapted than L. pyrotechnica to drought conditions, prevailing in the area under study. This judgement can be concluded by the average metabolic potentiality in the species, whereas soluble metabolites (soluble sugars and soluble proteins) were relatively much higher than in the case of L. pyrotechnica.