يمر العالم و المنطقة العربية وضعاً استثنائياً في ظل انتشار فايروس كورونا - 19 - المستحد وما تبعها من تداعيات على جميع الاصعدة في ظل تأثير تلك الجائحة وعلى شتى الاصعدة والمجالات كونها متداخلة ومترابطة معاً، ولاسيما القطاع الاقتصادي المهم الذي ينعكس بصورة مباشرة على المجالات الأخرى، لكون هذا الجانب الاساس الذي يميز المنطقة العربية فهي منطقة غنية بالموارد الطبيعية كالنفط و الغاز الطبيعي، فضلا عن الموقع الاسترا

The semiempirical (PM3) and DFT quantum mechanical methods were used to investigate the theoretical degradation of Indigo dye. The chemical reactivity of the Indigo dye was evaluated by comparing the potential energy stability of the mean bonds. Seven transition states were suggested and studied to estimate the actually starting step of the degradation reaction. The bond length and bond angle calculations indicate that the best active site in the Indigo dye molecule is at C10=C11.  The most possible transition states are examined for all suggested paths of Indigo dye degradation predicated on zero-point energy and imaginary frequency. The first starting step of the reaction mechanism is proposed. The change in enthalpy, Gibbs free energ

In this work was prepared three different types of modified screen printed carbon electrode (SPCEs) with drops casted method, the used carbone nanomaterials were the MWCNT, functionalized –MWCNT (f-MWCNT) and After several experiments were made to find an appropriate ratio to make good GOT/f-MWCNT nanocomposite, and found the suspension mixture (1:1) from GOT/f-MWCNT (f-MWCNT-GOT). The electrical and physical properties were performed with cyclic voltammeter technique, and studied the maximum current response, the effective surface area, effect of the pH value and the determination of active surface area for MWCNT-SPCE , f-MWCNT-SPCE and f-MWCNT-GOT/SPCE as (0.04 cm2), (0.119 cm2) and (0.115 cm2) respectively, the surface coverage concent

The addition of organic-inorganic hybrid nanoparticles presents a promising avenue for enhancing both the ionic conductivity at room temperature and the mechanical resilience of solid polymer electrolytes (SPEs). In this study, a novel nanocomposite solid polymer electrolytes (NSPEs) based on poly(ethylene oxide)-lithium difluoro(oxalato)borate (PEO20-LiDFOB) incorporating polyhedral oligomeric silsesquioxane-poly(ethylene glycol) (POSS-PEG(13.3)) hybrid nanoparticles were developed. And also reported the effect of POSS-PEG(13.3) hybrid nanoparticles on the structural, thermal, electrical, mechanical, and electrochemical properties of the (PEO20-LiDFOB) SPE. X-ray diffraction (XRD), differential scanning calorimetry analysis (DSC) and polar

Background: Polishing technique for acrylic resin material have great effect on properties of acrylic material and bacterial colonization such as staphylococcus aurous, which are responsible for many acrylic prosthetic infections such as the commonly ocular infections. Ineffective polishing technique could affect roughness and subsequently porosity of acrylic materials.So, a new effective method for polishing acrylic was used depending on the use of optiglaze coating material. So, this study aimed to evaluate the effect of optiglaze polishing on porosity of acrylic resin material and staphylococcus aurous activity in comparison to conventional polishing technique. 

Materials and methods: Specimen(n=120) were prepared :20 spe

Abstract

The toughening of epoxy resins with the addition of organic or inorganic compounds is of great interest nowadays, considering their large scale of applications. In the present work, composites of epoxy are synthesized with kaolin particles having different particle sizes as reinforcement. Composites of epoxy with varying concentration (0 to 40 weight %) of kaolin was prepared by using hand lay method. The variation of mechanical properties such as modulus of elasticity, yield, tensile, and compressive strength with filler content was evaluated. The composite showed improved modulus of elasticity and compressive properties on addition of filler. In contrast, the tensile and yield strength of the composite

Todays, World is faced an energy crisis because of a continuous increasing the consumption of fuels due to intension demand for all types of vehicles. This study is one of the efforts dealing with reduce the weight of vehicles by using a new material of sandwich steel, which consists of two skin steel sheets with core of a polymer material. Resistance spot welding (RSW) can be easily implemented on metals; however a cupper shunt tool was designed to perform the resistance welding of sandwich steel with DP800 cover sheets to resolve a non-conductivity problem of a polymer core. Numerical simulations with SORPAS^®3D were employed to test the weldability of this new material and supported by many practical experiments. In conclus

The current trend worldwide is searching plant extracts towards prevention of neurodegenerative disorders. This study aimed to investigate the neuroprotective effect of Alpinia galanga leaves (ALE), Alpinia galanga rhizomes (ARE), Vitis vinifera seeds (VSE), Moringa oleifera leaves (MLE), Panax ginseng leaves (PLE) and Panax ginseng rhizomes (PRE) ethanolic extracts on human neuroblastoma (SHSY5Y) cells. The 1‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging of VSE and MLE were 81% and 58%, respectively. Ferric‐reducing antioxidant power (FRAP) of ALE and MLE (33.57 ± 0.20 and 26.76 ± 0.30 μmol Fe(ΙΙ)/g dry wt., respectively) were higher than for the other extracts. Liquid chromatography coupled to quadrupole time‐of‐fli

The present study focused mainly on the vibration analysis of composite laminated plates subjected to
thermal and mechanical loads or without any load (free vibration). Natural frequency and dynamic
response are analyzed by analytical, numerical and experimental analysis (by using impact hammer) for
different cases. The experimental investigation is to manufacture the laminates and to find mechanical
and thermal properties of glass-polyester such as longitudinal, transverse young modulus, shear modulus,
longitudinal and transverse thermal expansion and thermal conductivity. The vibration test carried to
find the three natural frequencies of plate. The design parameters of the laminates such as aspect ratio,
thickness