Effect of structural changes of silica filler on the coefficient of thermal expansion (CTE) of underfill encapsulant

This study investigates the effect of degree of crystallinity (DC) of silica on the CTE value of epoxy filled silica composite. Various DC of silica was produced through high intensity grinding process in a jet mill by varying the grinding pressure. The ground silica with the DC ranging from 76% to 100% was filled at 45% volume and the CTE values were measured. The obtained results showed that CTE of composite was reduced as the filler's degree of crystallinity decreased.     

Principles of treatment of malignant gliomas in adults: an overview

The cornerstone of conventional treatments of malignant gliomas in adults has been surgical debulking, radiation therapy and chemotherapy. Almost always a combination of these treatments is used. With these conventional treatments the outcome, as measured by survival and quality of life, has remained universally dismal. Novel treatments, which are at different stages of laboratory and clinical trials, may offer a ray of hope for treatment of malignant gliomas. Development of these methods are directly related to the discoveries, over the past two decades, of cellular and molecular mechanisms involved in the genesis of brain tumors. Understanding of the mechanisms of tumor genesis may open new avenues of effective treatments for this devastating cancer.     

Optimization of Corynebacterium glutamicum Glutamic Acid Production by Response Surface Methodology

Response surface methodology (RSM) was used to evaluate the effects of fermentation parameters for glutamic acid (GA) production by Corynebacterium glutamicum CECT690 in submerged fermentation using palm date waste as substrate. To attain this purpose at the first stage, inoculum size, substrate concentration, penicillin concentration, phosphate concentration, and inoculum age were optimized for GA production. The next stage, the level of air flow rate in a 5-l fermenter (batch mode) which was run in optimized conditions was determined. The first stage gave the following results for the fermentation conditions optimized using RSM in 500-ml shake flasks: inoculum size 2% (v/v), substrate concentration 25% (w/v), penicillin concentration 1 U/ml, phosphate concentration 4 g/l, and inoculum age 10 h. Moreover, the maximum GA amount predicted by the model was 39.32 mg/ml. This was in agreement with the actual experimental value (36.64 mg/ml). In the second stage of the study, the amounts of GA were 118.75, 142.25, and 95.83 mg/ml in optimized conditions with the three levels of air flow rate of 0.6, 1.2, and 1.6 vvm, respectively. The present results demonstrate the potential of date waste juice as a substrate for producing GA by cultivation of C. glutamicum.     

Experimental and theoretical investigation of molecular diffusion coefficient of propylene in NMP

In this study, the absorption of propylene in N-methyl pyrolidone (NMP) was experimentally performed at three different temperatures (276.15, 293.15, and 328.15 K) using the pressure decay method and as a result, the equilibrium data, Henry's law constants, and kinetic data were reported. It was shown that the solubility and diffusivity are two important factors affecting the kinetic behavior of the system. This absorption system was mathematically modeled using Fick's second law accompanied by a time dependent boundary condition. An analytical method followed by numerical optimization was used to estimate the diffusion coefficient of propylene in NMP at different operating temperatures. The results demonstrated that the calculated diffusion coefficient obeys an Arrhenius type model. The resulting mathematical model was applied to calculate the number of absorbed moles of the gas. It shows a deviation of about 10% in comparison with the experimental measurements. Furthermore, the time dependent concentration profile along the liquid depth was also predicted.     

Broadband microwave absorber based on patterned surface structure

Journal of Materials Science: Materials in Electronics - The limitations of traditional flat microwave absorbers in terms of material parameters make it challenging to improve the working...     

Recyclable Magnetic Camphor Sulfonic Acid: A Reliable and Highly Efficient Ionic Organocatalyst for Benzothiazin-4-One Synthesis in Green Media

Catalysis Letters - Organocatalysts, like a minimalistic biocatalyst, pursue to reduce metal consumption with low cost, and low toxicity targeting to become a green strategy in organic...     

Enhancement of rheological and mechanical properties of bitumen using styrene acrylonitrile copolymer

In this research, styrene acrylonitrile copolymer as a novel additive is used to modify rheological, mechanical and thermal properties of the base bitumen 70 penetration grade. Styrene acrylonitrile copolymer combines the rigidity of polystyrene with the hardness and thermal resistance of polyacrylonitrile to enhance viscoelastic property of the bitumen. To investigate the performance of the proposed mixture, shear complex module, phase angle, penetration, softening point, and reversibility of prepared samples are measured at different additive content and compared with the base bitumen. The results show that softening point of the base and modified samples are 49–86°C, respectively. The rheological properties of the base bitumen and modified samples are measured by a dynamic shear rheometer (DSR). The phase angle as elasticity measure decreases from 55° to 35° in the modified bitumen compared to the base bitumen. Generally, the experimental results showed that styrene acrylonitrile copolymer makes bitumen to be more stable at high temperatures and more flexible at low temperatures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41875.     

Evaluation of mechanical and biocompatibility properties of hydroxyapatite/manganese dioxide nanocomposite scaffolds for bone tissue engineering application

The aim of this research was to evaluate the mechanical properties, biocompatibility, and degradation behavior of scaffolds made of pure hydroxyapatite (HA) and HA-modified by MnO₂ for bone tissue engineering applications. HA and MnO₂ were developed using sol-gel and precipitation methods, respectively. The scaffolds properties were characterized using X-ray diffraction (XRD), Fourier transform spectroscopy (FTIR), scanning electron microcopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The interaction of scaffold with cells was assessed using in vitro cell proliferation and alkaline phosphatase (ALP) assays. The obtained results indicate that the HA/MnO₂ scaffolds possess higher compressive strength, toughness, hardness, and density when compared to the pure HA scaffolds. After immersing the scaffold in the SBF solution, more deposited apatite appeared on the HA/MnO₂, which results in the rougher surface on this scaffold compared to the pure HA scaffold. Finally, the in vitro biological analysis using human osteoblast cells reveals that scaffolds are biocompatible with adequate ALP activity.