Regular Solution Theory Model Used To Predict Supercritical CO2 Extraction Of p-chlorophenol Contaminate From Water Stream.

The objective of this paper is the assessments of the feasibility of the extraction process utilizing a near critical carbon dioxide solvent with p-chlorophenol contaminate solute, which would be speeded up if it were possible to predict mutual solubility data

Temperature effects on the strengh properties of microbially stabilized residual soil

Microbially Induced Calcite Precipitation (MICP) is a rather new technology that has shown greater potential in geotechnical engineering applications. The technique utilizes the concept of microbial involvements in carbonate precipitation within the soil matrix that lead to the improvement in strength and stiffness of the soil. This paper evaluated the effects of temperature variations on the performance of microbial calcite precipitations in residual soil. The soil specimens were cured under different temperature conditions; that are atmospheric temperature, 40, 45 and 50° C. Shear strength, pH and amount of calcite precipitated were determined for each curing condition. A bacterial concentration of 1×105 cfu/ml and 0.5 M concentration of the cementation reagents were used for the study. The results indicated a general increase in strength with increase in curing temperature; which is an indication of temperature influence in bacterial activity. The results so far obtained also revealed that the higher the amount of calcite precipitated the more the strength improvement up to 48 hours treatment duration; after which increase in calcite content does not results in the increase in strength

Synthesized and extending the Bidentate Schiff base complexes using multilayer feedforward neural network

Complexes of Pd(II) and Ni(II) have been synthesized with general composition ML2X2 (M =Pd(II), Ni(II); L = benzylsalicylideneimine and X = OCH3, F). All synthesized compoundshave been characterized using elemental analysis, magnetic susceptibility measurements,infrared and NMR spectral studies that led to the conclusion that the ligands act as bidentatemanner to form square planar geometry for all complexes. As an extending work, the modeldevelopment of these complexes using multilayer feedforward neural network wereperformed. NiL1d, PdL1d, NiL1c and PdL1c were fed to the training network as inputs andbacteria as output. Levenberg Marquardt training algorithm was used during the networktraining with 10 nodes in hidden layer. The results of testing network showed that theregression, R is 1, indicating that the developed model is good. This is supported by the small mean square error (MSE) is 1.948x10-28 at epochs 5. The finding in this study is significant, thus contributed to the design of antibacterial agent especially to the bidentate Schiff base complexes.Keywords: Schiff base, palladium(II), nickel(II), antibacterial, regression, neural network

A New System of Parallel Isolated Nonthermal Filaments Near the Galactic Center: Evidence for a Local Magnetic Field Gradient

We report the discovery of a system of isolated nonthermal filaments approximately 0.5 deg. northwest (75 pc in projection) of Sgr A. Unlike other isolated nonthermal filaments which show subfilamentation, braiding of subfilaments, and flaring at their ends, these filaments are simple linear structures and more closely resemble the parallel bundled filaments in the Galactic center radio arc. However, the most unusual feature of these filaments is that the 20/90 cm spectral index uniformly decreases as a function of length, in contrast to all other nonthermal filaments in the Galactic center. This spectral gradient may not be due to simple particle aging but could be explained by a curved electron energy spectrum embedded in a diverging magnetic field. If so, the scale of the magnetic gradient is not consistent with a large scale magnetic field centered on Sgr A* suggesting that this filament system is tracing a local magnetic field.Comment: 10 pages, AASTeX 5.01 LaTeX2e; 7 figures in 9 PostScript files; scheduled for publication in the 2001 December 10, v. 563 issue of Ap

Comparative study of creep and fatigue crack growth in Poly (Vinyl chloride) pipe

The Rate theory of crack growth in PVC pipe has been studied for creep and fatigue crack propagation. Rate theory function parameters, (RTFP), were estimated theoretically from exponential function parameters, (EFP), to experimental data of crack velocity versus stress intensity factor ,(V-K) diagram, to creep crack propagation . Also (RTFP) were estimated theoretically from (EFP) to experimental data of (V-?K) diagram to fatigue crack propagation. Temperature effect with (RTFP) was discussed. Crack velocity function denoted with stress intensity factor and temperature degrees has been determined to fatigue and creep crack propagation theoretically and comparative results this function with experimental data of (V-K or ?K) diagram

Phase Equilibrium Data Study With Carbon Dioxide Solvent For 80.52:19.48 Of Ethanoloctane Mixture At Elevated Pressure.

Solubility data of a mixture containing 80.52 % ethanol and 19.48 % octane was measured in carbon dioxide solvent using a high-pressure type phase equilibrium apparatus at pressures up to 100 bar and at temperature of 75 °C. The experimental results showed that considerable separation was not achieved in this ethanol and octane ratio using carbon dioxide

Low-Frequency Radio Transients in the Galactic Center

We report the detection of a new radio transient source, GCRT J1746-2757, located only 1.1 degrees north of the Galactic center. Consistent with other radio transients toward the Galactic center, this source brightened and faded on a time scale of a few months. No X-ray counterpart was detected. We also report new 0.33 GHz measurements of the radio counterpart to the X-ray transient source, XTE J1748-288, previously detected and monitored at higher radio frequencies. We show that the spectrum of XTE J1748-288 steepened considerably during a period of a few months after its peak. We also discuss the need for a more efficient means of finding additional radio transients

A Low Frequency Survey of the Galactic Plane Near l=11 degrees: Discovery of Three New Supernova Remnants

We have imaged a 1 deg^2 field centered on the known Galactic supernova remnant (SNR) G11.2-0.3 at 74, 330, and 1465 MHz with the Very Large Array radio telescope (VLA) and 235 MHz with the Giant Metrewave Radio Telescope (GMRT). The 235, 330, and 1465 MHz data have a resolution of 25 arcsec, while the 74 MHz data have a resolution of 100 arcsec. The addition of this low frequency data has allowed us to confirm the previously reported low frequency turnover in the radio continuum spectra of the two known SNRs in the field: G11.2-0.3 and G11.4-0.1 with unprecedented precision. Such low frequency turnovers are believed to arise from free-free absorption in ionized thermal gas along the lines of site to the SNRs. Our data suggest that the 74 MHz optical depths of the absorbing gas is 0.56 and 1.1 for G11.2-0.3 and G11.4-0.1, respectively. In addition to adding much needed low frequency integrated flux measurements for two known SNRs, we have also detected three new SNRs: G11.15-0.71, G11.03-0.05, and G11.18+0.11. These new SNRs have integrated spectral indices between -0.44 and -0.80. Because of confusion with thermal sources, the high resolution (compared to previous Galactic radio frequency surveys) and surface brightness sensitivity of our observations have been essential to the identification of these new SNRs. With this study we have more than doubled the number of SNRs within just a 1 deg^2 field of view in the inner Galactic plane. This result suggests that future low frequency observations of the Galactic plane of similar quality may go a long way toward alleviating the long recognized incompleteness of Galactic SNR catalogs.Comment: 31 pages, 9 figures. Figure 7 is in color. Accepted to A