Interference Effects of Salinity on Growth and Some Metabolic Activities of Two Chlorella Species

The unicellular green algae Chlorella minutissima and Chlorella oocystoides were isolated from different regions in Upper Egypt. The effect of different concentrations of salinity (100, 250 and 500 mM NaCl) on growth parameters (optical density, dry weight, and total photosynthetic pigments) and primary products (total carbohydrates, total proteins, and lipids contents) were measured after 7 days. The growth parameters, and the primary products of Chlorella minutissima and Chlorella oocystoides were significantly increased at lower and moderate concentrations (100 and 250 mM NaCl). Under higher concentration 500 mM of NaCl, the growth parameters, and the primary products (total carbohydrates, and total proteins) were significantly decreased. However, the lipid contents were markedly increased.Keywords: Chlorella minutissima, Chlorella oocystoides, cell growth, total carbohydrates, total proteins and lipid contents

Interference Effects of Salinity on Growth and Some Metabolic Activities of Two Chlorella Species

The unicellular green algae Chlorella minutissima and Chlorella oocystoides were isolated from different regions in Upper Egypt. The effect of different concentrations of salinity (100, 250 and 500 mM NaCl) on growth parameters (optical density, dry weight, and total photosynthetic pigments) and primary products (total carbohydrates, total proteins, and lipids contents) were measured after 7 days. The growth parameters, and the primary products of Chlorella minutissima and Chlorella oocystoides were significantly increased at lower and moderate concentrations (100 and 250 mM NaCl). Under higher concentration 500 mM of NaCl, the growth parameters, and the primary products (total carbohydrates, and total proteins) were significantly decreased. However, the lipid contents were markedly increased

Microstructural study and numerical simulation of phase decomposition of heat treated Co–Cu alloys

The influence of heat treatment on the phase decomposition and the grain size of Co–10 at% Cu alloy were studied. Few samples were aged in a furnace for either 3 or 5 h and then quenched in iced water. The materials and phase compositions were investigated using energy dispersive spectrometry and X-ray diffraction techniques. X-ray diffraction analysis showed that the samples contained Co, Cu, CuO, CoCu2O3, CoCuO2 phases in different proportions depending on the heat treatment regimes. The formation of dendrite Co phase rendered the spinodal decomposition while the oxidations prevent the initiation of the spinodal decomposition even for a deep long aging inside the miscibility gap. Since the Bragg reflections from different phases of Co–Cu alloy significantly overlap, the crystal structural parameters were refined with FULLPROF program. The shifts in the refined lattice constants (a, b and c), the space group and the grain size were found to be phase- and heat treatment-dependant. Two-dimensional computer simulations were conducted to study the phase decomposition of Co–Cu binary alloy systems. The excess free energy as well as the strain energy, without a priori knowledge of the shape or the position of the new phase, was precisely evaluated. The results indicate that the morphology and the shape of the microstructure agree with SEM observation

Ameliorating the Mechanical Parameters, Thermal Stability, and Wettability of Acrylic Polymer by Cement Filling for High-Efficiency Waterproofing

Acrylic polymer/cement nanocomposites in dark and light colors have been developed for coating floors and swimming pools. This work aims to emphasize the effect of cement filling on the mechanical parameters, thermal stability, and wettability of acrylic polymer. The preparation was carried out using the casting method from acrylic polymer coating solution, which was added to cement nanoparticles (65 nm) with weight concentrations of (0, 1, 2, 4, and 8 wt%) to achieve high-quality specifications and good adhesion. Maximum impact strength and Hardness shore A were observed at cement ratios of 2 wt% and 4 wt%, respectively. Changing the filling ratio has a significant effect on the strain of the nanocomposites. The contact angle was increased as the concentration of additives and cement increased, indicating that the synthesized coating is not hydrophilic and does not allow water permeability through it. The results show that the acrylic polymer/cement with a cement ratio of 8 wt% is the best nanocomposite for high-efficiency waterproofing

Controlling the Structural Properties and Optical Bandgap of PbO–Al2O3 Nanocomposites for Enhanced Photodegradation of Methylene Blue

In the present work, PbO-x wt% Al2O3 nanocomposites (where x = 0, 10, 20, 30, 40, 50, 60, 70, and 100 wt%) were prepared by a microwave irradiation method. Their structural parameters, morphology, and chemical bonds, were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR). It was noticed that the produced phases have an orthorhombic crystal structure and the smaller average crystallite sizes were formed when the ratio of Al2O3 is 40 wt%. The FTIR analysis reveals the formation of various bonds between Al or Pb and O. The TEM analysis reveals that the PbO-x%Al2O3 composites (x = 20, 40, and 60), composed of dense particles, and their size are smaller compared to the pure Al2O3 sample. The optical bandgap obeys the direct allowed transition and decreases from 4.83 eV to 4.35 eV as the PbO ratio in the composites increases from 0 to 100%. The intensity of the photoluminescence emission, at the same wavelength, increases as the PbO ratio increases from 0% to 60% implying that increasing the PbO content increases the capacity of free carriers within the trap centers. The prepared composites are used as a catalyst to remove the methylene blue (MB) from the wasted water under UV-visible or visible light irradiations. The photocatalytic degradation of MB was investigated by applying various kinetic models. It was found that the PbO-30% Al2O3, and PbO-40% Al2O3 composites are the best ones amongst other compositions. Furthermore, the pseudo-second-order model is the best model for describing the deterioration mechanism among the models studied. The formed composites could be suitable for the degradation of organic dyes for water purification as well as applications that required a higher optical bandgap

Controlling the Structural Properties and Optical Bandgap of PbO–Al₂O₃ Nanocomposites for Enhanced Photodegradation of Methylene Blue

In the present work, PbO-x wt% Al2O3 nanocomposites (where x = 0, 10, 20, 30, 40, 50, 60, 70, and 100 wt%) were prepared by a microwave irradiation method. Their structural parameters, morphology, and chemical bonds, were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR). It was noticed that the produced phases have an orthorhombic crystal structure and the smaller average crystallite sizes were formed when the ratio of Al2O3 is 40 wt%. The FTIR analysis reveals the formation of various bonds between Al or Pb and O. The TEM analysis reveals that the PbO-x%Al2O3 composites (x = 20, 40, and 60), composed of dense particles, and their size are smaller compared to the pure Al2O3 sample. The optical bandgap obeys the direct allowed transition and decreases from 4.83 eV to 4.35 eV as the PbO ratio in the composites increases from 0 to 100%. The intensity of the photoluminescence emission, at the same wavelength, increases as the PbO ratio increases from 0% to 60% implying that increasing the PbO content increases the capacity of free carriers within the trap centers. The prepared composites are used as a catalyst to remove the methylene blue (MB) from the wasted water under UV-visible or visible light irradiations. The photocatalytic degradation of MB was investigated by applying various kinetic models. It was found that the PbO-30% Al2O3, and PbO-40% Al2O3 composites are the best ones amongst other compositions. Furthermore, the pseudo-second-order model is the best model for describing the deterioration mechanism among the models studied. The formed composites could be suitable for the degradation of organic dyes for water purification as well as applications that required a higher optical bandgap

Assessment of groundwater aquifer using geophysical and remote sensing data on the area of Central Sinai, Egypt

Abstract The study aims to assess groundwater resources in Sinai's central area using remote sensing, geoelectric, and well-logging data, utilising techniques for modelling hydrogeological frameworks and evaluating desert regions' groundwater potential. Its utilized satellite image sources, soil maps, and geological maps to map the effects of various factors on groundwater potentiality recharge, dividing it into five zones. Eighteen deep VES stations were used to examine the upper part of the groundwater aquifer in Central Sinai, Egypt, comparing it with available borehole information (Well-1, and JICA-1) to establish subsurface geology and hydro-geology positioning. Borehole data, VES interpretation results, hydro-geophysical maps, and four geoelectrical cross-sections were used to visualize the rearward expansion of eight lithological units, groundwater-bearing sections, and aquifer-filled thicknesses. From interpretation data output reveal three zones with significant recharge and storage potential, including two groundwater aquifers. The shallow aquifer has a saturation thickness of the fractured limestone of 35–250 m, while the deep aquifer Nubian sandstone is detected at depths ranging from 660–1030 m. NW–SE and NE–SW faults likely recharge conduits connecting shallow and deep aquifers, providing sites with acceptable groundwater potential for living, agriculture, and development in Sinai