Transient Aero-Thermal Mapping of Passive Thermal Protection System for Nose-Cap of Reusable Hypersonic Vehicle

The temperature field history of passive Thermal Protection System (TPS) material at the nose-cap (forward stagnation region) of a Reusable Hypersonic Vehicle (RHV) is generated. The 3-D unsteady heat transfer model couples conduction in the solid with external convection and radiation that are modeled as time-varying boundary conditions on the surface. Results are presented for the following two cases: (1) nose-cap comprised of ablative TPS material only (SIRCA/PICA), and (2) nose-cap comprised of a combination of ablative TPS material with moderate thermal conductivity and insulative TPS material. Comparison of the temperature fields of SIRCA and PICA [Case (1)] indicates lowering of the peak stagnation region temperatures for PICA, due to its higher thermal conductivity. Also, the use of PICA and insulative TPS [Case (2)] for the nose-cap has higher potential for weight reduction than the use of ablative TPS alone

Adiantum philippense L. frond assisted rapid green synthesis of gold and silver nanoparticles

Development of an ecofriendly, reliable, and rapid process for synthesis of nanoparticles using biological system is an important bulge in nanotechnology. Antioxidant potential and medicinal value of Adiantum philippense L. fascinated us to utilize it for biosynthesis of gold and silver nanoparticles (AuNPs and AgNPs). The current paper reports utility of aqueous extract of A. philippense L. fronds for the green synthesis of AuNPs and AgNPs. Effect of various parameters on synthesis of nanoparticles was monitored by UV-Vis spectrometry. Optimum conditions for AuNPs synthesis were 1 : 1 proportion of original extract at pH 11 and 5 mM tetrachloroauric acid, whereas optimum conditions for AgNPs synthesis were 1 : 1 proportion of original extract at pH 12 and 9 mM silver nitrate. Characterization of nanoparticles was done by TEM, SAED, XRD, EDS, FTIR, and DLS analyses. The results revealed that AuNPs and AgNPs were anisotropic. Monocrystalline AuNPs and polycrystalline AgNPs measured 10 to 18 nm in size. EDS and XRD analyses confirmed the presence of elemental gold and silver. FTIR analysis revealed a possible binding of extract to AuNPs through –NH2 group and to AgNPs through C=C group. These nanoparticles stabilized by a biological capping agent could further be utilized for biomedical applications

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ABSTRACT The oral delivery of lipophilic drugs presents a major challenge due to low aqueous solubility of such compounds. Clopidogrel is a BCS class II prodrug specifically and irreversibly inhibits the platelets aggregation by blocking activation of the glycoprotein IIb /IIIa pathway. The chief intention of this work is to develop an orally stable self Nano-emulsifying drug delivery system by evaluating its in vitro potential. Components of SNEDDS were assessed by solubility studies on various oils, surfactant, co-surfactants and co solvents. Ternary phase diagrams were constructed to identify area of nanoemulsification for the selected systems. Characterization of SNEDDS was done by Physical method, Droplet size, Zeta potential determination, drug loading capacity, Transmission test, Cloud point measurement and in vitro release study. The optimal Formulation consisted of mixture of Drug (13.05%), Acrysol K150 and PEG 400 (1:1) and Capmul MCM NF (17.39%). Droplet size of optimal batch was 22.91 nm with PdI 0.173.Drug loading capacity was 2 times the Actual dose of CLP (75 mg). Transmission values were above 99% in pH 1.2, Ph 6.8 and distilled water. Cloud point of formulations was above 65°C. In vitro release inspection of optimal formulation illustrated a complete release of Clopidogrel from SNEDDS within 15 min. Our study concludes that the SNEDDS shows potential approach for the poorly water soluble drugs including Clopidogrel

Research of design and analysis integrated information modeling framework for multibody mechanical system: with its application in the LHD design

Many complex mechanical products can be considered as multibody systems; 3D computer-aided design (CAD), multibody dynamics, finite element-based strength and fatigue analyses, optimization, and other CAE tools, are often used to develop this kind of product. But design is difficult and challenging because of information inconsistence among different engineering domains, and isolated information model islands exist. Lots of research are attracted to design and analysis information integration, but attentions are mainly focused on integration of CAD–finite element analysis (FEA), supporting the bottom-up design principle, while multibody dynamics analysis for analyzing global performance of a mechanical system is rarely considered, which follows the top-down design principle. In this paper, a novel multilevel system representation modeling framework for supporting both bottom-up and top-down or mixed design methods is proposed. It can integrate the product design CAD models with multibody dynamics, finite element-based strength and fatigue analyses, realizing a CAD–dynamic–FEA–fatigue analysis integration. It can also support data exchange and transfer in multidomain analyses. The framework is illustrated with a case study of a load haul dump (LHD) design using currently available software tools. Furthermore, a design case study of the working unit of the LHD is given to highlight the applicability of the modeling framework for multibody mechanical systems. It has been demonstrated that the framework can describe information exchanging and integration among CAD, FEA-based strength and fatigue analyses, and multibody dynamics analysis during a multibody mechanical product design process