Fate of wheat bound malathion residues in rats during gestation

Malathion [S-1,2-di(ethoxycarbonyl) ethyl 0,0-dimethyl phosphorodithioate], treated wheat when stored for 28 months at 20 degrees C with or without food grade white mineral oil on grains contained about 62 and 79% of the applied insecticide as bound residues, respectively. These bound residues were present mainly in the form of the parent compound. The stored wheat containing bound malathion residues, as well as wheat material freshly spiked with malathion were fed to rats during gestation. No residues of malathion and/or metabolites were detected in urine, feces and body tissues. Further no significant effect on body weight, serum chemistry and cytochrome P450 levels were observed in the mothers. There was no evidence for the histopathological alteration or teratogenic anomalies in the fetuses. However, placental transfer of malathion was indicated by the presence of the insecticide residues in fetuses from rats fed wheat material containing bound residues.     

Reconstructing 3-D objects from 2-D boundaries

In this article, two fully implemented algorithms for reconstructing 3-D object models based on two or more 2-D boundaries is introduced. Assuming that the 2-D pixel-based boundaries are generated by using boundary detection algorithms in the image preprocessing session (which is beyond the scope of this article), the 3-D reconstruction goes through two stages. First, the linear regression based line-segmentation algorithm is applied to convert each original pixel-based boundary to a best-fit line segment based polygonal boundary. Then, the 3-D surface reconstruction algorithm is used to cover the surface between each pair of neighboring polygonal boundaries. An important feature of our approach is that it allows easy control of the resolution of the reconstructed 3-D models by setting the error-threshold in the line-segmentation algorithm     

An analytical approach for the inverse scattering solution of radially inhomogeneous spherical bodies using higher order TE and TM illuminations

A novel method for the reconstruction of inhomogeneous permittivity profiles of spherical dielectric objects illuminated by higher order TE/sub mn/ and TM/sub mn/ spherical modes is presented. The overall technique is based on the derivation of Riccati-similar nonlinear differential equations in a spherical coordinate system for both TE and TM illuminations as a part of the direct problem formulation. These differential equations are then inverted using a quasi-linear approach to obtain a closed-form expression of the radially varying permittivity profile of spherical objects in terms of a spherical Fourier-Bessel transform of the measured spectral domain reflection coefficient data. To validate the proposed method, several examples with different mode illuminations and with different noise levels are considered for reconstructions. A good agreement between the actual and the reconstructed permittivity profiles even under high noisy conditions shows that our method is not much sensitive to the presence of noise in the reflection coefficient data.     

Microstructure and hardness studies of the electron beam welded zone of Hastelloy C-276

Electron beam welding (EBW) technique is becoming popular in nuclear, chemical and aerospace industries due to its high penetration depth and fast cooling rate. Samples of Hastelloy C-276 have been welded by electron beam (EB). A scanning electron microscope (SEM) having the attachment of an energy dispersive system (EDS) has been employed to study the resulting microstructure and micro-eutectic phases. The microstructure of the molten zone (MZ) is found to be of fine lamellar type. The hardness of the MZ is found to be 35% higher compared to as-received alloy. The micro-eutectoids are rich in Mo and W. The X-ray diffraction patterns of the MZ show shifting of peaks towards higher angle compared to the diffraction pattern of the as-received alloy. Broadening of the peaks is also observed in the diffraction pattern of the MZ. Formation of the μ-phase was observed in the MZ after a tempering treatment at 950 °C.     

Processing, microstructure, properties and wear behavior of in situ synthesized TiB2 and TiC thick films on steel substrates

TiB₂ and TiC reinforced Fe matrix thick films (2 mm thickness) were produced through the synthesis reaction from Ti, C and FeB powders with varying porosity on the steel substrates. Powder technology was used as a processing method. The films and the substrates were sintered in a single step. TiB₂, TiC and Fe were detected in the films by X-ray diffraction analysis. The fact that no other reaction product was detected revealed the thermal stability of TiB₂ and TiC. The formation of secondary reaction products was inhibited during the reactive sintering. The films showed maximum strength of 163-466 MPa when sintered separately at 1350 °C. The strength of the films varied with their porosity. The films showed considerable bonding strength with the steel substrates. The delamination of the films from the steel substrates was observed at stress values from 454-781 MPa. The microstructure, fracture and delaminated surface morphologies were studied. The wear resistance against hardened high speed steel was studied in reciprocating sliding tests. The wear mechanisms were discussed by means of microscopical observation on the worn surfaces.     

Plastic deformation of Ni-Cr single crystals

Single crystals of nickel containing up to 21.5 at pct Cr have been deformed in tension over the temperature interval 78 to 623°K. The critical resolved shear stress of alloys containing up to 9 at. pct Cr in the region of the athermal plateau can be fitted into aC ^1/2 andC ^2/3 relationship whereC is the concentration of chromium. The observed magnitude of hardening, however is larger than that predicted by the theory of Fleischer or that of Labusch. Rapid solution hardening in alloys having 9 to 21.5 pct Cr arises due to the presence of short range order. The work hardening parameters are examined and the temperature and strain rate dependence of the stress at the onset of dynamic recovery has been used to evaluate the stacking fault energy as a function of chromium content.     

A comparative study of the stress field around a reinforced and an unreinforced normal intersection of two cylindrical shells

The results of a comparative study of the effects of reinforcement on the stress fields in the critical intersection region of two normally intersecting cylindrical shells are presented. The results for in-plane and out-of-plane moments have been obtained experimentally by the use of electrical resistance foil gages, and numerically by the use of a three-dimensional finite element program. The finite element analysis also includes internal pressure loading. A comparison of results obtained by using a thin shell element with six degrees of freedom at each of the four nodes (three displacements and three rotations) and a three-dimensional element with three displacement degrees of freedom at each of the eight nodes, is also given.     

Thermo-physical properties of coal under transient conditions

Coal samples were obtained along the vertical axis in an eight-inch diameter experimental moving bed coal gasifier. This system had a throughput of half a tonne of sized (6 × 20 mm) coal per day. The specific heat and thermal conductivity were measured using the line heat-source method with a transient sample temperature. The coal sample was heated at a rate of 4 K/min during the property measurement. The heat capacity and thermal conductivity were obtained from an iterative fit of the experimental data to the heat conduction equation taking due account of the probe size and contact resistance. The apparatus was tested with samples of known properties such as alumina powder and glass micro-beads. The measurements reported here cover the range from 300–700 K. Effects of surface moisture and pyrolysis reactions can be identified. The results are compared with data in the literature measured at constant sample temperatures. The line source technique is well suited to transient property measurements.     

The coating of nickel compounds with copper compounds

Uniform fine particles of nickel basic carbonate were synthesized by heating, aqueous solution containing 0.08 mol dm⁻³ nickel sulfate and 0.8 mol dm⁻³ urea, at 85°C for various periods of time. These particles were then coated with copper compound by heating them in aqueous dispersion, containing urea and copper nitrate, at 85°C. The coating material was found to be amorphous and was composed of Cu₂(OH)₂CO₃. The coating mixture, when heated under similar conditions in the absence of the dispersed cores, produced greenish dispersion of the precipitated particles [coating precursor solids]. The later were also amorphous in nature and had the same chemical composition [Cu₂(OH)₂CO₃] as that of the coating material of the coated particles. Air-dried core, coated, and coating precursor materials were calcined at 700°C for 1 h at the heating rate of 5°C min⁻¹ in the air atmosphere, which converted them into NiO, NiO_[core]/CuO_[coating], and CuO, respectively. Scanning electron microscopic examination showed no sintering occurred in all these solids during the calcinations process and the particles retained their identities to a significant extent.     

An experimental investigation into uncatalyzed oxidation of toluene and pseudocumene by sulfur dioxide

The uncatalyzed oxidation of toluene and pseudocumene by sulfur dioxide has been studied at pressures ranging from 200 to 300 atm; and at tempratures from 250 to 350°C. It was found that under these conditions, toluene is readily oxidized and that the main oxidation product is benzoic acid. Pseudocumene, however, oxidizes to mono- and di-carboxylic acids rather than to trimellitic acid. Power law rate equations are proposed for the two oxidations. Activation energy for toluene oxidation is estimated to be 47.6 Kcal/gm. mole while for pseudocumene oxidation the value is 71.2 Kcal/gm. mole.