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.     

Characterization and Beneficiation of Gold Mining By-products as Source of High-Quality Silica for High Technical Applications; Response Surface Studies and Optimization

Silicon - This paper aims to evaluate and upgrade the quality of quartz mining by-products through acid leaching process. The quartz samples were collected as gold mine by-products from El Sid-...     

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...     

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.     

Corrosion Inhibition of Novel Prepared Cationic Surfactants for API N80 Carbon Steel Pipelines in Oil Industries

The objective of this study is to investigate the corrosion inhibition of API N80 steel pipelines in 1M HCl solution by a synthesized compound (N-(3-(dimethyl octyl ammonio) propyl) palmitamide bromide, subjected to four different modes of measurements. Weight loss (WL) was investigated at five different temperatures: 25–60°C, while potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) were tested at 25°C. The result showed that the synthesized inhibitor was good and its protection efficiency (%η) significantly increased by increasing both the dose and the temperature. The polarization curve revealed that the studied inhibitor acts as mixed-type of inhibitor. Adsorption of the investigated inhibitor led to a reduction in the double layer capacitance and an increase in the charge transfer resistance. The adsorption of this inhibitor was found to obey the Langmuir adsorption model. The thermodynamic parameters were calculated and discussed. A clear correlation was found between corrosion protection efficiency and theoretical parameters obtained using density functional theory.     

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.     

Warm Deformation Microstructure of a Plain Carbon Steel

 Grain refinement in a plain carbon steel under intercritical warm deformation was studied by torsion testing. Based on the experimental results, the warm flow behaviour and microstructural evolution of ferrite were researched with particular emphasis on the effect of the strain rate in controlling the grain refinement mechanism of ferrite. The deformed microstructures were investigated at various strain rates using optical microscopy and electron back-scattered diffraction (EBSD). The EBSD observations indicate that an increase in the strain rate leads to the development of new fine ferrite grains with high angle boundaries. Furthermore, it shows that the annihilation of dislocations occurs more readily at lower strain rate. The elongated ferrite grains continuously dynamically recrystallize to form the equiaxed fine ferrite grains. Thereby, the aspect ratio of elongated grains decreases with increasing the strain rate. Furthermore, the peak stress and steady state stress of ferrite both increase with increasing strain rate. Based on the study, the effect of strain rate on the development of fine ferrite grains during continuous dynamic recrystallization of ferrite was analyzed in detail.     

Highly Conductive Carbon Nanotube‐Graphene Hybrid Yarn

An efficient procedure for the fabrication of highly conductive carbon nanotube/graphene hybrid yarns has been developed. To start, arrays of vertically aligned multi‐walled carbon nanotubes (MWNT) are converted into indefinitely long MWNT sheets by drawing. Graphene flakes are then deposited onto the MWNT sheets by electrospinning to form a composite structure that is transformed into yarn filaments by twisting. The process is scalable for yarn fabrication on an industrial scale. Prepared materials are characterized by electron microscopy, electrical, mechanical, and electrochemical measurements. It is found that the electrical conductivity of the composite MWNT‐graphene yarns is over 900 S/cm. This value is 400% and 1250% higher than electrical conductivity of pristine MWNT yarns or graphene paper, respectively. The increase in conductivity is asssociated with the increase of the density of states near the Fermi level by a factor of 100 and a decrease in the hopping distance by an order of magnitude induced by grapene flakes. It is found also that the MWNT‐graphene yarn has a strong electrochemical response with specific capacitance in excess of 111 Fg^?1. This value is 425% higher than the capacitance of pristine MWNT yarn. Such substantial improvements of key properties of the hybrid material can be associated with the synergy of MWNT and graphene layers in the yarn structure. Prepared hybrid yarns can benefit such applications as high‐performance supercapacitors, batteries, high current capable cables, and artificial muscles.     

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.