The Upper Cretaceous-Lower Paleogene succession at Gabal Qreiya area that covers six rock units, Quseir, Duwi, Dakhla, Tarawan, Esna, and Thebes formations, is reviewed through a high-resolution sequence stratigraphic analysis. Six third-order depositional sequences and their associated surfaces and systems tracts are recognized based on stratigraphic, sedimentological, and high-resolution foraminiferal studies. The pre-Campanian sequence, comprising the Quseir Formation, was accumulated in inner neritic paleodepths, on marginal to shallow subtidal shelf. The Lower Campanian sequence that covers the Duwi Formation was accumulated in oscillating settings between inner to middle neritic paleodepths, on a shallow subtidal shelf. The Upper Campanian-Maastrichtian sequence that covers the lower part of the Dakhla Formation was accumulated in outer neritic-upper bathyal to middle neritic paleodepths, on a deep subtidal shelf to a shallow subtidal shelf. The Danian sequence that covers the middle part of the Dakhla Formation was accumulated in oscillating conditions between upper bathyal and middle neritic paleodepths, on a deep subtidal and a shallow subtidal shelf. The Selandian-Thanetian sequence that comprises the upper part of the Dakhla, Tarawan, and the lower part of the Esna formations was accumulated in fluctuating conditions from upper bathyal to middle neritic paleodepths, on a deep subtidal to a shallow subtidal shelf. The Ypresian sequence that includes the main parts of Esna and Thebes formations was accumulated in fluctuating settings among middle bathyal and middle neritic paleodepths, on a deep subtidal to a shallow subtidal shelf. Most of the sequence boundaries coincide with the global sea-level curve whereas some of them suggest a local tectonic event.

TWELVE seasons of 2015 in two tributaries of Wadi Qena (Wadi El-Atrash and Wadi El-Ghuza) in stands of Aerva javanica shrubs were visited during the winter and summer the Egyptian Eastern Desert. Soil analysis showed low contents of soil moisture (SMC) and organic matter and slight alkalinity. Chlorophyll contents (Chl. a & b) and their ratio increased significantly during summer season, while their stability index increased during winter. The contents of Ca and K were high during summer, while PO4 and Na were higher during winter. Soluble sugars and soluble proteins increased during summer while total free amino acids were higher during winter. It can be concluded that there are close relationships between the high K, Ca and Cl contents and the hot-dry conditions prevailed in the summer season, and the accumulation of soluble sugars (SS) and soluble proteins (SP) on the relatively humid-cold season. Statistical correlations showed important positive relations between soil Na and plant water content (PWC), chlorophyll parameters, SS and SP. Fortunately, there was negative relation between soil PO4 and the contents of Na and Cl in the shoots. Spatial variations were the most important factor that controls A. javanica PWC, Na, K, Ca, Cl, PO4, Chl. a and b, SS and SP. While, Mg, chlorophyll a stability index (CSI a), CSI b and total amino acids (TFAA) were affected by the variation in both spatial and temporal gradients.

TWELVE seasons of 2015 in two tributaries of Wadi Qena (Wadi El-Atrash and Wadi El-Ghuza) in stands of Aerva javanica shrubs were visited during the winter and summer the Egyptian Eastern Desert. Soil analysis showed low contents of soil moisture (SMC) and organic matter and slight alkalinity. Chlorophyll contents (Chl. a & b) and their ratio increased significantly during summer season, while their stability index increased during winter. The contents of Ca and K were high during summer, while PO4 and Na were higher during winter. Soluble sugars and soluble proteins increased during summer while total free amino acids were higher during winter. It can be concluded that there are close relationships between the high K, Ca and Cl contents and the hot-dry conditions prevailed in the summer season, and the accumulation of soluble sugars (SS) and soluble proteins (SP) on the relatively humid-cold season. Statistical correlations showed important positive relations between soil Na and plant water content (PWC), chlorophyll parameters, SS and SP. Fortunately, there was negative relation between soil PO4 and the contents of Na and Cl in the shoots. Spatial variations were the most important factor that controls A. javanica PWC, Na, K, Ca, Cl, PO4, Chl. a and b, SS and SP. While, Mg, chlorophyll a stability index (CSI a), CSI b and total amino acids (TFAA) were affected by the variation in both spatial and temporal gradients.

The present study was carried out to evaluate the allelopathic potential of ten common weeds against three crop plants. All weeds extracts, even those more diluted, completely prevented seeds of Eruca sativa from germination. The high extract strength of Ammi majus and Desmostachya bipinnata prevented seeds of Triticum aestivum and Vicia faba from germination. The germination percentage, seed vigor index, coefficient of velocity and seedling length of T. aestivum and V. fabadifferentially inhibited by the extracts of weeds. The rate of elongation of hypocotyl and epicotyl of T. aestivum inhibited by all weeds, while the low extract strength of six weeds stimulated the rate of elongation in V. faba sprouts. All estimated germination and elongation parameters of receiving plants negatively correlated by total phenolics, flavonoids and alkaloids in donor weeds. Terpenoids were less influence and weakly correlated with germination parameters, so it suggested to be stimulatory. The magnitude of allelopathic effect, inhibitor or stimulator, was primarily depends on the donor plant and its content of secondary metabolites and secondarily on the target species as indicated by 2. The weeds exerting negative allelopathy can be categorized into competitive weeds which inhibit cell division and elongation or phytotoxic weeds that germination-preventing.

The present study was carried out to evaluate the allelopathic potential of ten common weeds against three crop plants. All weeds extracts, even those more diluted, completely prevented seeds of Eruca sativa from germination. The high extract strength of Ammi majus and Desmostachya bipinnata prevented seeds of Triticum aestivum and Vicia faba from germination. The germination percentage, seed vigor index, coefficient of velocity and seedling length of T. aestivum and V. fabadifferentially inhibited by the extracts of weeds. The rate of elongation of hypocotyl and epicotyl of T. aestivum inhibited by all weeds, while the low extract strength of six weeds stimulated the rate of elongation in V. faba sprouts. All estimated germination and elongation parameters of receiving plants negatively correlated by total phenolics, flavonoids and alkaloids in donor weeds. Terpenoids were less influence and weakly correlated with germination parameters, so it suggested to be stimulatory. The magnitude of allelopathic effect, inhibitor or stimulator, was primarily depends on the donor plant and its content of secondary metabolites and secondarily on the target species as indicated by 2. The weeds exerting negative allelopathy can be categorized into competitive weeds which inhibit cell division and elongation or phytotoxic weeds that germination-preventing.

This paper presents a new strategy for developing back-side illuminated dye-sensitized solar cells (DSSCs) using nanoporous alumina substrate containing Cu impurities. The presence of a traces of Cu in the aluminum leads to the formation of 3D nanoporous anodic aluminum oxide (AAO) structure which consisted of an array of cylindrical pores interconnected by horizontal holes. Under different anodizing conditions, four different AAO substrates were fabricated and applied for developing DSSCs. The current-voltage characteristics of the DSSCs were measured and compared. Results obtained indicated that the performance (photocurrent density, open-circuit photovoltage and efficiency) of DSSCs based on 3D AAO was significantly enhanced compared to those of FTO/TiO2. The efficiencies of DSSCs based on alumina P90A, P90B and OX60 were improved by 172%, 51%, and 274%, respectively. The enhancement in photocurrent and efficiency is attributed to the reduction in the carrier recombination, uniform distribution of the dye molecules inside the vertical tubes, horizontal interconnections of pores as well as a reduction in pore size. This indicates that AAO based DSSCs can contribute significantly to energy harvesting from the sun.

This paper presents a new strategy for developing back-side illuminated dye-sensitized solar cells (DSSCs) using nanoporous alumina substrate containing Cu impurities. The presence of a traces of Cu in the aluminum leads to the formation of 3D nanoporous anodic aluminum oxide (AAO) structure which consisted of an array of cylindrical pores interconnected by horizontal holes. Under different anodizing conditions, four different AAO substrates were fabricated and applied for developing DSSCs. The current-voltage characteristics of the DSSCs were measured and compared. Results obtained indicated that the performance (photocurrent density, open-circuit photovoltage and efficiency) of DSSCs based on 3D AAO was significantly enhanced compared to those of FTO/TiO2. The efficiencies of DSSCs based on alumina P90A, P90B and OX60 were improved by 172%, 51%, and 274%, respectively. The enhancement in photocurrent and efficiency is attributed to the reduction in the carrier recombination, uniform distribution of the dye molecules inside the vertical tubes, horizontal interconnections of pores as well as a reduction in pore size. This indicates that AAO based DSSCs can contribute significantly to energy harvesting from the sun.

This paper presents a new strategy for developing back-side illuminated dye-sensitized solar cells (DSSCs) using nanoporous alumina substrate containing Cu impurities. The presence of a traces of Cu in the aluminum leads to the formation of 3D nanoporous anodic aluminum oxide (AAO) structure which consisted of an array of cylindrical pores interconnected by horizontal holes. Under different anodizing conditions, four different AAO substrates were fabricated and applied for developing DSSCs. The current-voltage characteristics of the DSSCs were measured and compared. Results obtained indicated that the performance (photocurrent density, open-circuit photovoltage and efficiency) of DSSCs based on 3D AAO was significantly enhanced compared to those of FTO/TiO2. The efficiencies of DSSCs based on alumina P90A, P90B and OX60 were improved by 172%, 51%, and 274%, respectively. The enhancement in photocurrent and efficiency is attributed to the reduction in the carrier recombination, uniform distribution of the dye molecules inside the vertical tubes, horizontal interconnections of pores as well as a reduction in pore size. This indicates that AAO based DSSCs can contribute significantly to energy harvesting from the sun.

The unique properties of Gemini surfactants and their variety of applications encouraged many researchers to synthesize more of these compounds. Herein, we constructed new cationic Gemini surfactants by using aromatic spacers with different chain lengths. The critical micelle concentration value for each surfactant was determined using the electrical conductivity measurements. The variety of aggregation behaviors of Gemini surfactants was studied by using atomic force microscopy, which encouraged us to use these surfactants in the preparation of mesoporous silica NPs. Our results indicated that we have succeeded in finding a new soft-template for preparing uniform small size hollow spheres mesoporous silica NPs of a diameter depending on the used surfactant. Moreover, we investigated the effect of pH value on the morphology of the prepared silica, which indicated that using of acidic media resulted in the formation of hollow micro-particles instead of hollow NPs. Furthermore, the anticorrosion efficiency of these surfactants in comparing with cetyltrimethylammonium bromide (CTAB) as a positive control was investigated by monitoring the corrosion rate of iron sheets in 0.5M of hydrochloric acid based on weight loss method. Our results indicated that all the prepared Gemini surfactants possessed higher anti-corrosion efficiency at very low concentrations than CTAB surfactant.

The unique properties of Gemini surfactants and their variety of applications encouraged many researchers to synthesize more of these compounds. Herein, we constructed new cationic Gemini surfactants by using aromatic spacers with different chain lengths. The critical micelle concentration value for each surfactant was determined using the electrical conductivity measurements. The variety of aggregation behaviors of Gemini surfactants was studied by using atomic force microscopy, which encouraged us to use these surfactants in the preparation of mesoporous silica NPs. Our results indicated that we have succeeded in finding a new soft-template for preparing uniform small size hollow spheres mesoporous silica NPs of a diameter depending on the used surfactant. Moreover, we investigated the effect of pH value on the morphology of the prepared silica, which indicated that using of acidic media resulted in the formation of hollow micro-particles instead of hollow NPs. Furthermore, the anticorrosion efficiency of these surfactants in comparing with cetyltrimethylammonium bromide (CTAB) as a positive control was investigated by monitoring the corrosion rate of iron sheets in 0.5M of hydrochloric acid based on weight loss method. Our results indicated that all the prepared Gemini surfactants possessed higher anti-corrosion efficiency at very low concentrations than CTAB surfactant.