Oxidation stability of blends of Jatropha biodiesel with diesel

Biodiesel, an ecofriendly and renewable fuel substitute for diesel has been receiving the attention of researchers around the world. Due to heavy import of edible oil, the production of biodiesel from edible oil resources in India is not advisable. Therefore it is necessary to explore non-edible seed oils, like Jatropha curcas (J. curcas) and Pongamia for biodiesel production. The oxidation stability of biodiesel from J. curcas oil (JCO) is very poor and therefore an idea is given to increase the oxidation stability of biodiesel by blending it with petro-diesel. J. curcas biodiesel (JCB), when blended with petro diesel leads to a composition having efficient and improved oxidation stability. The results have shown that blending of JCB with diesel with less than 20% (v/v) would not need any antioxidants but at the same time, need large storage space. Similarly, if the amount of diesel is decreased in the blend, it will require the addition of antioxidant but in lesser amount compared to pure JCB. For the purpose five antioxidants were used namely butylated hydroxytoluene (BHT), tert-butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), propyl gallate (PG), and pyrogallol (PY). A B₃₀ blend (30% JCB in the blend of JCB and petro-diesel) has been tested for the same purpose. PY is found to be the best antioxidant among all five antioxidants used. The optimum amount of antioxidant (PY) for pure biodiesel tested for the present experiment is around 100 ppm while it is around 50 ppm for B₃₀ blend to maintain the international specification of oxidation stability.     

Microstructure,thermomechanical properties,and electrical conductivity of carbon black‐filled nylon‐12 nanocomposites prepared by selective laser sintering

Selective laser sintering (SLS) is employed to fabricate a multifunctional polymer nanocomposite comprising Nylon‐12 reinforced with carbon black (CB) at a loading of 4% by weight. The heat distortion temperature (HDT), viscoelastic properties, and the electrical conductivity of this nanocomposite are compared to those obtained via extrusion injection molding (Ex‐IM). The HDT of the nanocomposites made by the two methods are found to be nearly identical. The electrical conductivity of the nanocomposite made by SLS is five orders of magnitude higher than that obtained through Ex‐IM. The storage modulus of the SLS‐processed nanocomposite is at least one order of magnitude higher than that of the nanocomposite made by Ex‐IM, for all the frequencies tested. The observed differences in properties and the effects of the processing methods on the polymer's molecular weight, its crystallization characteristics, and the dispersion of CB within the polymer matrix are investigated using X‐ray diffraction, differential scanning calorimetry, and scanning electron microscopy. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Effect of laser source nonlinearity on optical heterodyne interferometry

In this paper, an optical heterodyne interferometric detection model with a frequency-ramped laser diode (LD) has been analyzed. The effect of the nonlinearity of the LD source on the optical heterodyne interferometry has been investigated in two different ways, which are the power-distortion Fourier series analysis and the harmonic distortion analysis. The general formulation between the tangent of the tested phase and the interference fringe have been presented with the analysis of the beat signal in the frequency domain by each methodology. The numerical results of these formulations have been presented.     

Study of some sulphur-group solvents for aromatics extraction by gas chromatography

Nineteen organosulphur solvents have been studied by gas chromatography as potential solvents for the extraction of aromatics. The activity coefficients of nine typical hydrocarbon solutes have been determined in these solvents at three temperatures. From the activity coefficient data, the selectivities of all the solvents have been calculated for benzene with respect to each of the other hydrocarbons in order to screen them for extraction studies. Solvent losses in the g.c. column were also studied.     

Dip Coating of Nano Hydroxyapatite on Titanium Alloy with Plasma Assistedγ-Alumina Buffer Layer:A Novel Coating Approach

This paper reported a novel coating approach to deposit a thin,crack free and nano-structured hydroxyapatite （HA） film on Ti6AI4V alloy with Al₂O₃ buffer layer for biomedical implants.The Al₂O₃ buffer layer was deposited by plasma spraying while the HA top layer was applied by dip coating technique.The X-ray diffraction（XRD） and Raman reflections of alumina buffer layer showedα- toγ-AI₂O₃ phase transformation; and the fractographic analysis of the sample revealed the formation of columnar grains in well melted splats. The bonding strength between Al₂O₃ coating and Ti6AI4V substrate was estimated to be about 40 MPa.The presence of dip coated HA layer was confirmed using XRD,scanning electron microscopy（SEM） and energy dispersive X-ray spectroscopy（EDX） analysis.The SEM images exhibited that HA top layer enveloped homogenously the troughs and crests of the underneath rough（R_a= 2.91 |im） Al₂O₃ surface.It is believed that the novel coating approach adopted might render the implant suitable for rapid cement-less fixation as well as biocompatible for longer periods.     

基于Photogrammetry的地表变形监测技术研究

主要讨论了采用Photogrammetry技术监测地下施工过程中地表变形的主要方法和应用情况。地表变形过大往往会导致地表既有建筑物的破碎,所以量化监测其变形程度在地下施工中尤为重要。Photogrammetry技术是一种非接触式的变形监测技术,主要通过影像手段获取目标点的三维变形大小。该方法需要从空间多角度对目标点进行摄影测量,获取连续的三维影像信息,通过Photogrammetry软件进行现场目标点重现,进而获取三维可视目标点坐标值。本文通过现场的监测,获取了地表变形的数据,提出了监测的方法。     

CONTROLLED VARIATION SCHEME IN A SEQUENTIAL SOLVER FOR RECIRCULATING FLOWS,PART I: THEORY AND FORMULATION

The formalism of the total variation diminishing (TVD) schemes is utilized to design a convection scheme for incompressible recirculating flows. The scheme has been named the controlled variation scheme (CVS). Even though the CVS does not possess the TVD property for sequential solution algorithms, due to the appearance of source terms, the concept of controlled variation fluxes can be effective in suppressing spurious oscillations that commonly occur in convection-dominated viscous flows, by injecting a nonlinear numerical diffusion, similar to the original TVD schemes, into the central difference scheme. This is demonstrated by using the one-dimensional linear convection-diffusion equation with and without a source term as model problems. The formulation and an efficient implementation of the CVS in a sequential pressure-based solver for incompressible steady-state Navier-Stokes equations is presented in this work. The applications of the CVS for two-dimensional laminar and turbulent flows is presented in Part II of the present work.     

Review of different test methods for the evaluation of stability of biodiesel

The vegetable oil, fats and their biodiesel suffer with the drawback of deterioration of its quality when it is in contact with oxygen unlike petroleum diesel. There are various types of stabilities like oxidation, storage and thermal, playing key roles in making the fuel unstable. The present paper is an attempt to review all type of stability measuring test methods to find out the best method for stability measurement. From the review it is found that there are several methods to measure the stability of biodiesel but two test methods emerges the most likely choice for the purpose of measurement of oxidation stability of biodiesel. These are ASTM 2274 and 743 Rancimat test. A comparison between these two shows that these may be used alternatively. Most commonly used methods to investigate the thermal stability are Rancimat test, ASTM D 6408-08, D 5304-06 and TGA/DTA. Rancimat test has been suggested as an important method to measure the thermal stability of oils, fats and biodiesel fuels.     

Polyurethane waterproofing coating for building applications

In India problems of moisture leakage and dampness in buildings are widespread. Waterproofing treatments, including surface coating, have shown success to a varying degree. A two-component polyurethane system based on predominantly indigenous raw materials has been developed and thoroughly evaluated in the laboratory for its efficacy. Field trials have also been carried out and some results are reported.     

Computer aided design of inverted strip dielectric waveguide millimeter-wave couplers

A computer aided design technique has been developed for the design of a beam splitter coupler and a distributed type coupler using inverted strip dielectric waveguides. The optical beam principle has been used for the beam splitter coupler. Numerical results for these couplers at 80 GHZ with minimum directivity of 30 dB and VSWR of 1.15 have been presented.