Testing of felt-ceramic materials for combustor applications

The feasibility of using composite felt ceramic materials as combustor liners was experimentally studied. The material consists of a porous felt pad sandwiched between a layer of ceramic and one of solid metal. Flat, rectangular test panels, which encompassed several design variations of the basic composite material, were tested, two at a time, in a premixed gas turbine combustor as sections of the combustor wall. Tests were conducted at combustor inlet conditions of 0.5 MPa and 533 K with a reference velocity of 25 m/s. The panels were subjected to a hot gas temperature of 2170 K with 1% of the total airflow used to film cool the ceramic surface of the test panel. In general, thin ceramic layers yield low ceramic stress levels with high felt ceramic interface temperatures. On the other hand, thick ceramic layers result in low felt ceramic interface temperatures but high ceramic stress levels. Extensive thermal cycling appears to cause material degradation, but for a limited number of cycles, the survivability of felt ceramic materials, even under extremely severe combustor operating conditions, was conclusively demonstrated

Rank-Sparsity Incoherence for Matrix Decomposition

Suppose we are given a matrix that is formed by adding an unknown sparse matrix to an unknown low-rank matrix. Our goal is to decompose the given matrix into its sparse and low-rank components. Such a problem arises in a number of applications in model and system identification, and is NP-hard in general. In this paper we consider a convex optimization formulation to splitting the specified matrix into its components, by minimizing a linear combination of the $\ell_1$ norm and the nuclear norm of the components. We develop a notion of \emph{rank-sparsity incoherence}, expressed as an uncertainty principle between the sparsity pattern of a matrix and its row and column spaces, and use it to characterize both fundamental identifiability as well as (deterministic) sufficient conditions for exact recovery. Our analysis is geometric in nature, with the tangent spaces to the algebraic varieties of sparse and low-rank matrices playing a prominent role. When the sparse and low-rank matrices are drawn from certain natural random ensembles, we show that the sufficient conditions for exact recovery are satisfied with high probability. We conclude with simulation results on synthetic matrix decomposition problems

VITAMIN B1PROMOTED GREEN SYNTHESIS OF BENZOFURAN CHALCONES: PROMISING SCAFFOLDS FOR DRUG DEVELOPMENT IN ANTIMICROBIAL

 Objective: To develop metal free and environmentally benign synthetic method for the synthesis of chalcones bearing benzofuran scaffolds. Materials and Methods:Starting material chloroacetone,anhydrous potassium carbonate, different aromatic aldehydes, ethanol and vitamin B1 of AR grade wereused for synthesis.Various chalcones were synthesized byClaisen-Schmidt condensation.The structure of the synthesized compounds was confirmed by elemental analysis, IR,1H NMR and mass spectra.  Results:In this context we have tried new metal free and environmentally benign synthetic method for synthesis of the pharmaceutically important molecule 1-(4-substituted-1-benzofuran-2-yl) substituted chalcones and its derivatives and it was screened for their antimicrobial activity.Most of the compounds exhibited the good to moderate activity. Conclusion:Herein we have tried a highly efficient protocol for the synthesis of chalconesa good result with variety of functionalities, a high yield of products, and the recoverability of this catalyst.Vitamin B1 as a catalyst has been developed using green solvent EtOH

Travel to extraterrestrial bodies over time: some exploratory analyses of mission data

This paper discusses data pertaining to space missions to astronomical bodies beyond earth. The analyses provide summarizing facts and graphs obtained by mining data about (1) missions launched by all countries that go to the moon and planets, and (2) Earth satellites obtained from a Union of Concerned Scientists (UCS) dataset and lists of publically available satellite data

A review on biogenic synthesis of gold nanoparticles, characterization, and its applications

The nano-sized particles make an imprint on us in our daily lives and it has great importance in the numerous fields of biotechnology like the food industry, medical and industrial field. Gold nanoparticles are one of the widely used particles as it has many therapeutic applications, such as drug delivery system for many diseases like cancer, cardiovascular diseases, diabetes mellitus etc. biosensors, and environmental applications of dye degradation, bioremediation of toxic chemicals present in the environment (soil and atmosphere). Gold nanoparticles synthesis by the green route has become the latest development, because of the bioavailability of sources like plants or microorganisms, and it also reduces the utilization of toxic chemicals. This review explains the various microorganisms like bacteria, algae, fungi, actinomycetes and yeast involved in the synthesis of these nanoparticles also elucidate the size, shape and functional groups involved in the synthesis of nanoparticles and its applications

A Model for Thermal Growth of Ultrathin Silicon Dioxide in O2 Ambient: A Rate Equation Approach

A new thermal oxidation model based on a rate equation approach with concentration dependent diffusion coefficient is proposed for ultrathin SiO2 for thicknesses of the order of 100 Å. The oxidation reaction of silicon is assumed to be dependent on the concentrations of unreacted silicon and oxygen. The results of oxide thickness versus oxidation time for various growth conditions and activation energies for diffusion coefficients are in agreement with various experimental data for O2 ambient

Synthesis of zinc oxide nanoparticles using plant leaf extract against urinary tract infection pathogen

In modern science, Nanotechnology is an ablaze field for the researchers. Zinc oxide nanoparticles (ZnO NPs) are known to be one of the most multifunctional inorganic nanoparticles with its application in treatment of urinary tract infection. Nanoparticles were synthesized using Passiflora caerulea fresh leaf extract and were characterized by UV-visible spectroscopy (UV-vis), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Energy dispersive analysis of x-ray (EDAX), Atomic force microscopy (AFM). Therefore, the study reveals an efficient, eco-friendly and simple method for the green synthesis of multifunctional ZnO NPs using P. caerulea. Urinary tract infection causing microbes were isolated from the disease affected patient urine sample. The synthesized nanoparticles have been tested against the pathogenic culture showed a very good zone of inhibition compared with plant extract. It indicates the biomedical capability of ZnO NPs

Traditional Uses of Some Medicinal Plants by tribals of Gangaraju Madugula Mandal of Visakhapatnam District, Andhra Pradesh

During the years 2007-2008 several field trips were conducted to document the ethnomedicinal remedies for 47 diseases with 90 plant species of Angiosperms from three major tribes viz: Bagatas, Konda Doras and Valmikis who have been residing in Gangaraju Madugula Mandal of Visakhapatnam district. The plants were deposited as herbarium specimens in Andhra University, Visakhapatnam, India

SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM MARINE BROWN SEAWEED AND ITS ANTIFUNGAL EFFICIENCY AGAINST CLINICAL FUNGAL PATHOGENS

Objectives: The aim of this study is to synthesize silver nanoparticles using the algal extract of Padina tetrastromatica and evaluate its antifungal activity against pathogenic fungus isolated from clinical samples.Results: Formation of brown color at 15 minutes indicates the production of silver nanoparticles by the extract of brown algae P. tetrastromatica. Surface plasmon resonance band was centered at 440 nm which was observed by UV-vis spectrophotometer. SEM image revealed spherical and cubical nanoparticles with high agglomeration, and energy-dispersive X-ray illustrates elemental components of silver formed at 3 keV. TEM shows spherical, truncated, and ellipsoidal nanoparticles and also it evidences the algae compounds that are capped with nanoparticles. SAED pattern proved four diffraction face-centered cubic rings at (111), (200), (220), and (311) which indicates the crystalline nature of nanoparticles. Silver nanoparticles show high inhibition activity against Fusarium sp, Aspergillus niger, Candida albicans, Aspergillus fumigatus, and Aspergillus flavus at different concentrations. P. tetrastromatica-mediated synthesis of silver nanoparticles shows rapid and eco-friendly silver ion reduction process.Methods: Dried algal biomass was used to prepare the pure algal extract and added with 1 mM AgNO , and the color change was noted and recorded by ultraviolet (UV)-vis spectrophotometer. The morphological characteristics were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Crystalline structure was analyzed by SAED pattern. Antifungal activity was performed by agar well diffusion method against various pathogenic fungi.Conclusion: Therefore, this present study elucidates that algae-mediated synthesized silver nanoparticles have antifungal activity against pathogenic fungi, so it can be developed as a novel medicine for human welfare in biomedical applications in the near future.Keywords: Padina tetrastromatica, Silver nanoparticles, Transmission electron microscopy, Antifungal activity, Green synthesis.Â