The analysis of nonlinear three dimensional frames

The problems involved in the analysis of three dimensional frames of non-prismatic members, made of nonlinearly elastic material are investigated. The sources of nonlinearity considered are material behavior and interaction of loads and small deformations. The material response is expressed in the form of a table of uniaxial stress and related strain with monotonically increasing values. This table is used to create a table of bending moment-curvature relationships for beams at a discrete number of cross-sections along their length and also a table of the axial load-biaxial moments-biaxial curvatures relationships for eccentrically loaded columns. These tables are then used to obtain the responses of structural members to different loadings. Length effects in the columns and sidesway in the frame are both considered. The Displacement Method of structural analysis is used with an incremental loading approach to analyze three dimensional frames made of materials whose stress-strain curves were assumed to be of circular or parabolic form, at different load patterns and magnitudes. It was found that the combination of three dimensional and nonlinear material effects on the magnitudes of the frame moments is important when compared to the moments obtained by linear, plane frame analysis, and that the assumption of linear behavior may give results which are in error by more than 30 per cent for high axial loads on columns.

It appears that the method, developed herein, of representing material and member behavior in tabular form, offers a very direct and versatile approach to the problem of analyzing structures made of several different and/or nonlinearly elastic materials.     

A note on the problem of edge crack in a semi-circular plate

International Journal of Fracture -     

Studies on anodic oxide coating with low absorptance and high emittance on aluminum alloy 2024

Anodization of AA 2024 in sulfuric acid bath containing glycerol, lactic acid and ammonium metavenadate has been studied to develop white anodic oxide coating. Investigation on the influence of various operating parameters — coating thickness, current density and ammonium metavenadate concentration on the optical properties was carried out to optimize the process. Infrared, atomic absorption spectroscopic techniques and scanning electron micrograph were used to characterize the coating. The obtained oxide coating provides a ratio of solar absorptance (α) to infrared emittance (), as low as 0.2. The optical properties and hardness values measured under optimum experimental conditions support its use as a thermal control coating.     

Hierarchical nanostructured ZnO with nanorods engendered to nanopencils and pin-cushion cactus with its field emission study

In the present investigation, we report the synthesis of highly crystalline ZnO nanorods engendered to pin-cushion cactus and 1D nanopencil like nanoforms on zinc (Zn) foil via a simple sonochemical assisted hydrothermal route. The work reported herewith is attractive for two reasons: (i) the facile one step solution approach assisted by prior ultrasonication converts nanorods/nanobelts into nanopencils, and (ii) the sharp and quasi-aligned ZnO nanopencils are potential field electron emitters. In addition, the controlled growth of pinhole like ZnO nanopencils and aligned hexagonal ZnO nanodisc was obtained. The changes in the growth rate, diameter, density, and surface area of highly oriented ZnO nanorods are examined. Considering the significances of such novel morphologies, technically detailed formation mechanism has been proposed. The field emission study of pin-cushion cactus like ZnO nanopencils was performed. Field emission measurements demonstrate remarkably low turn-on field which is explained on the basis of a sequential enhancement mechanism involving the consecutive stem and tip contribution. The Folwer-Nordheim (F-N) plot showed nonlinear behavior indicating the semiconducting nature of the emitter. Significantly, emission current is stable at the preset value of 3 μA over the period of 3 h. The simplicity of the synthesis route coupled with the promising emission properties is envisaged to be an important candidate for potential nanoelectronic devices. These unique imperative ZnO nanostructures may have potential for sensors, solar cell, photocatalysis, varisters, etc.     

Spectrally resolved phase-shifting interference microscopy: technique based on optical coherence tomography for profiling a transparent film on a patterned substrate

Spectrally resolved white-light phase-shifting interference microscopy has been used for measurements of the thickness profile of a transparent thin-film layer deposited upon a patterned structure exhibiting steps and discontinuities. We describe a simple technique, using an approach based on spectrally resolved optical coherence tomography, that makes it possible to obtain directly a thickness profile along a line by inverse Fourier transformation of the complex spectral interference function.     

Novel nanoplex‐mediated plant transformation approach

Here, a rapid and easy transformation by electroporation technique for gene transfer in plants using cell penetrating amino nanocomplex (nanoplex) has been demonstrated in Nicotiana. Nanoplex was prepared using cell penetrating amino acids (CPAs) such as poly‐L‐lysine (PLL) and Argenine (Arg), in combination with the gold nanoparticles (AuNPs). PLLs‐modified nanoplex with zeta potential of 34.2 ± 1.22 mV charge showed 63.3% efficiency for gene transformation in plant cells as compared to 60% when modified with Arg and the zeta potential was found to be 30.0 ± 0.83 mV; whereas, the transformation efficiency without nanoplex was found to be 6.6%. The findings indicate that the zeta potential of positively charged nanocomplex (AuNPs/CPAs/DNA/CPAs) increases the transformation efficiency because of their ability to protect the DNA from electroporation wave and endogenous enzyme damage. Transformation was confirmed by GUS assay and amplification of npt gene. This technique may open up new possibilities of gene transfer in plants, which will enable to produce large number of transgenic plants.Inspec keywords: biochemistry, electrokinetic effects, DNA, biomedical materials, nanomedicine, nanoparticles, gold, cellular biophysics, enzymes, genetics, molecular biophysics, genomicsOther keywords: nanoplex‐mediated plant transformation approach, electroporation technique, gene transfer, cell penetrating amino nanocomplex, cell penetrating amino acids, poly‐L‐lysine, Arg, gold nanoparticles, PLLs‐modified nanoplex, zeta potential, gene transformation, plant cells, transformation efficiency, positively charged nanocomplex, electroporation wave, npt gene, transgenic plants, AuNPs‐CPAs‐DNA‐CPAs, voltage 32.980000000000004 mV to 35.42 mV, voltage 29.169999999999998 mV to 30.830000000000002 mV, Au     

Qrtzgeotherm: An ActiveX component for the quartz solubility geothermometer

An ActiveX component, QrtzGeotherm, to calculate temperature and vapor fraction in a geothermal reservoir using quartz solubility geothermometry was written in Visual Basic 6.0. Four quartz solubility equations along the liquid–vapor saturation curve: (i) a quadratic equation of 1/T and pressure, (ii) a linear equation relating log SiO₂ to the inverse of absolute temperature (T), (iii) a polynomial of T including logarithmic terms and (iv) temperature as a polynomial of SiO₂ including logarithmic terms are programmed.The QrtzGeotherm has input parameters: (i) HRes—the reservoir enthalpy (kJ/kg), (ii) SiO2TD—silica concentration in total discharge (ppm), (iii) GeoEq—number of quartz solubility equation and (iv) TempGuess—a guess value of the reservoir temperature (°C). The reservoir enthalpy H_res is assumed to be the same as the total discharge enthalpy H_R. The output parameters are (i) TempRes—reservoir temperature (°C) and (ii) VapRes—reservoir vapor fraction.The first step is to calculate the total discharge concentration of silica SiO2TD from the concentration of silica SiO2Col of separated water, sampled after N-separations of vapor and water. To use QrtzGeotherm in MS-Excel, three functions SiO2TD, GeoResTemp and GeoResVap for an N-stage separation of geothermal reservoir fluid are written in Visual Basic for Application (VBA). Similarly, a demonstration program, QrtzGeothrm, is written in Visual Basic 6.0.     

Bacteriological quality of sheep meat in Mhow town of India

The purpose of this study was to investigate bacterial load in ready‐to‐sale sheep meat with special reference to Salmonella. Samples were collected from 100 sheep carcasses from retail meat shops in domestic markets. On carcasses, where bacterial counts were obtained, the mean of the log₁₀ aerobic plate count was 7.26 cfu g^?1, and that of total coliform count and total Escherichia coli count was 4.11 log₁₀ cfu g^?1 and 3.03 log₁₀ cfu g^?1, respectively. All the samples (100) were found positive for coliforms, 49.0% were positive for E. coli and 3.0% were positive for Salmonella. The isolates were serotyped as Salmonella infantis having antigenic structure 6, 7: r: 1, 5. Antibiogram revealed highest (100.0%) sensitivity towards amikacin, ceftriaxone, ciprofloxacin, chloramphenicol, colistin sulphate, gentamicin and nalidixic acid followed by cefuroxime and tetracycline (66.67% each) and cotrimoxazole (33.33%). All the strains were resistant to ampicillin.     

Unsteady reverse osmosis or ultrafiltration in a tube

The unsteady behavior of a tubular hyperfiltration system, with both a pulse and a continuous feed, is analyzed using a significant extension of miscible dispersion theory. The extension permits one to treat unsteady convective diffusion in systems with convection at interfacial boundaries in a relatively straightforward manner. It is shown that such convection can effect an enormous reduction in axial dispersion in such systems.

A superposition integral is used to generalize the solution for the pulse input to reverse osmosis systems with continuous feeds which may be subject to arbitrary fluctuations in feed concentrations.