Photoelectric properties of undoped and lithium-doped Zn1−xMgxTe alloys

The room temperature photoelectric response of undoped and lithium-doped Zn_1–xMg_xTe (0 x 0.50) alloys has been measured in the wavelength range 0.50 3.0 m. The response curve for undoped samples is characterized by a single peak in the band edge region. The peak shifts with composition in accordance with the expected shift in the energy band gap. Lithium-doped samples show an additional peak centred at 1.04 eV for all compositions. This peak is attributed to photo-generated holes in the split-off band created as the result of electronic transitions to shallow acceptor impurities.     

A multi-variate heart disease optimization and recognition framework

Neural Computing and Applications - Cardiovascular diseases (CVD) are the most widely spread diseases all over the world among the common chronic diseases. CVD represents one of the main causes of...     

Synthesis,Characterization, Surface and Biological Activity of Diquaternary Cationic Surfactants Containing Ester Linkage

Two series of diquaternary cationic surfactants designated as E9Nm and E11Nm having two different alkyl chains in their chemical structure were synthesized. The chemical structures of these surfactants were confirmed using elemental analysis, FTIR and ¹H‐NMR spectra. The surface activities of the different surfactants were determined using surface and interfacial tension at 25 °C. The surface parameters including: critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area were determined. The surface activities of the cationic surfactants were correlated with their chemical structure. The surface activities of the surfactants increased with increasing the hydrophobic chain length. The adsorption and micellization tendencies of the surfactants in solution were determined using the free energies of adsorption and micellization. The synthesized surfactants were evaluated as biocides against bacteria and fungi. Biocidal activity data showed that a gradual increase in the hydrophobic chain length of the surfactant molecules gradually increases the efficiency of these surfactants as biocides.     

Study on compatibility of recycled polypropylene/high-density polyethylene blends using rheology

The compatibilization of recycled polypropylene (PP) and high-density polyethylene (HDPE) was studied using two types of compatibilizers: 5 wt% PP-grafted-maleic anhydride (5 wt% MAPP) and 5 wt% HDPE-grafted-maleic anhydride (5 wt% MAHDPE), using a cone and plate rheometer. Maleic anhydride (MAH) was grafted onto PP or HDPE via peroxide initiated melt grafting technique. Blends containing highest amount of pure HDPE exhibited maximum values for tensile strength, complex viscosity, dynamic and loss modulus compared to similar blends developed using recycled HDPE. The latter properties of all the compatibilized blends were higher compared to that of uncompatibilized blends. Studies on rheology of the pure and recycled polymer and its compatibilized blends have thrown some light on the molecular weight distribution of these materials. High shear yielding characteristics were noted for MAHDPE compatibilized blends containing high percentage of HDPE. Scanning electron microscopy showed that blends containing a high percentage of HDPE and HDPE based compatibilizer exhibit a dispersed morphology. Fourier transform infrared spectrometer characterization was conducted to check if compatibilization occurred between recycled PP and HDPE.     

Novel Gemini Cationic Surfactants: Thermodynamic,Antimicrobial Susceptibility,and Corrosion Inhibition Behavior against Acidithiobacillus ferrooxidans

The Egyptian oil and gas industry is suffering from severe metal corrosion problems, particularly microbial-induced corrosion. There is limited knowledge on the corrosion inhibition of carbon steels in the presence of an acidophilic, iron-oxidizing bacterial species Acidithiobacillus ferrooxidans. Therefore, in this study, novel Gemini cationic surfactants, in three forms depending on variation in alkyl chains of 8, 12, and 16 carbon atoms named FHPAO, FHPAD, and FHPAH, respectively, were synthesized and characterized by Fourier transform infrared and nuclear magnetic resonance spectroscopy. The surface parameters and the thermodynamic of the synthesized surfactants were evaluated at three different temperatures, 20, 40, and 60 °C. The synthesized Gemini cationic surfactants were tested as broad-spectrum antimicrobial, antibacterial and anticandida agents. They evaluated as biocides and corrosion inhibitors against Acidithiobacillus ferrooxidans. FHPAD showed higher adsorption ability at the solution interface and higher affinity to construct micelles than FHPAO and FHPAH. Both adsorption and micellization processes were hydrophobic and temperature dependent. FHPAO, FHPAD and FHPAH exhibited wide-spectrum antimicrobial activities, and the highest activity and the lowest minimum bactericidal/fungicidal inhibitory concentrations were attributed to FHPAD. Furthermore, synthesized FHPAD demonstrated the highest metal corrosion inhibition efficiency of 95.5% at 5 mM in comparison to 87.5% and 81.7% for FHPAO and FHPAH, respectively. In conclusion, this study provides novel synthesized cationic surfactants with many applications in the oil and gas industry, such as broad-spectrum antimicrobial, biocides, and corrosion inhibitors for acidophilic, iron-oxidizing bacterial species Acidithiobacillus ferrooxidans.     

Antibacterial activity of chitosan against Aeromonas hydrophila

The effect of chitosan on growth and production of haemolysin by Aeromonas hydrophila was investigated as well as the effects of temperature, pH, salts and irradiation on the antibacterial activity of chitosan. It was found that chitosan affected growth and haemolysin production of A. hydrophila in varying degrees compared to the control. Growth and haemolysin production were clearly suppressed at 0.04% of chitosan. Suppression was more effective at pH 6.0 than at pH 7.0. The bactericidal effects of chitosan increased with increasing temperature and decreasing pH. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Sodium ions at concentrations of 10 and 25 mM also reduced chitosan's activity. Irradiation of chitosan at 150 kGy under dry condition was effective in slightly increasing its activity.     

Recycling of glass in synthesis of MCM-48 mesoporous silica as catalyst support for Ni<Subscript>2</Subscript>O<Subscript>3</Subscript> photocatalyst for Congo red dye removal

Glass was successfully recycled in the synthesis of mesoporous silica MCM-48 which was used as catalyst support for nickel oxide photocatalyst. The resulted products were evaluated using X-ray diffraction, scanning electron microscope and UV–Vis spectrophotometer. The precipitated nickel oxide is of Ni₂O₃ form and loading of it onto MCM-48 resulted in a reduction in the band gap energy from about 3.66 eV to about 2.4 eV. The role of MCM-48 as catalyst support for Ni₂O₃ in enhancing the adsorption capacity and photocatalytic properties of nickel oxide was evaluated through series of equilibrium studies and photocatalytic degradation of Congo red dye under visible light. Using of glass-based MCM-48 as catalyst support for Ni₂O₃ showed enhancing the adsorption capacity by 31.3 and 14.8% higher than the adsorption capacity of Ni₂O₃ and MCM-48, respectively. Also, the photocatalytic degradation percentage increased by about 67.3% relative to the Ni₂O₃ degradation percentage. The nature of MCM-48/Ni₂O₃ adsorption mechanism is chemisorption and occurs in multilayer form throughout the heterogeneous surface of the composite. The using of MCM-48 as support for Ni₂O₃ photocatalyst enhanced the adsorption capacity through increasing the total surface area. The loading process resulted in fixing of the Ni₂O₃ particles throughout the porous structure which producing more exposed active photocatalyst sites and active adsorption sites for the incident photons as well as preventing the nickel oxide particles from agglomeration. Based on the obtained results, supporting of Ni₂O₃ particles onto MCM-48 is promising active centers for the degradation of Congo red dye molecules.     

Indicators and Aspects of Hydrological Drought in Lebanon

Change in climate conditions has become a global issue that has given a serious concern by many researchers. However, the availability of data in this regard is considered as a major element for optimum comparative analysis. The Mediterranean region is influenced by climate change, which is reflected mainly by its impact on water sources supply and flow regime. In Lebanon, these water sources are witnessing obvious quantitative decrease, thus affected the supply side, the so-called “hydrologic drought”. Therefore, many studies have been made to figure out a comprehensive understanding on water resources in Lebanon and their interrelation with climatic trends, but they often analyze one component of the water cycle. This study involves different indices of surface and subsurface water, thus, followed a comparative analysis of different hydrologic records. This was achieved by applying graphical illustrations of the numerical values adopted from available records. In this regard, different tools of analysis were used, and more certainly remotely sensed data were helpful for monitoring approaches. Therefore, results of the obtained comparative analysis revealed a clear regression in the amount of available water from different sources in Lebanon. These sources, which are under the impact of human like rivers and groundwater, showed a 23–29% decrease in the amounts of water since the last four decades. While sources, with less human interference, like snow cover and precipitation have been decreased by 12–16%. However, in both cases, the status is quite alarming and needs immediate water management plans to conserve water resources in Lebanon.     

Stress analysis of multi-layer electronic and mechanical systems (MEMS) under fatigue and impact loading conditions

Detailed micro electronic and mechanical systems (MEMS) for a mobile microprocessor complex shape were modeled using Finite Element (FE) processing. Fatigue and impact conditions were performed on the Ball Grid Array (BGA) Integrated Circuit (IC) using Abaqus\CAE finite element analysis software. The main objective of this research is to make sure that BGA products can endure the roughness of the daily usage, where a portable electronic product is habitually coupled with potential damage of functional failure when the device falls.     

Characterization of cobalt oxide nanocatalysts prepared by microemulsion with different surfactants, reduction by hydrazine and mechanochemical method

Cobalt oxide (Co₃O₄) nanoparticles were prepared by different techniques (i) by microemulsion with different surfactants, (ii) by reduction as nanometal with hydrazine hydrates and (iii) by thermal treatment of precursor obtained from mechanochemical reaction of Co(NO₃)·H₂O with NH₄HCO₃. The products were calcined at 400 °C to give crystalline Co₃O₄. The obtained different samples of Co₃O₄ were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM) from which the particle size was calculated. The results revealed that all samples obtained from different methods were nanosized particles.