An FFT-based algorithm for reconstructing inhomogeneous circular cylindrical shells from noisy data

The inverse problem of reconstructing an inhomogeneous, circular, cylindrical shell, from the knowledge of scattering data, is of importance in diverse fields, including the imaging of thin veins and arteries in medicine, of co-axial cables in non-destructive testing, and of volcanic pipes in volcanology. Optical fibres provide another important example of shells evaluated by such non-invasive means. In as much as the problem has such diverse applications, it will be useful to have an algorithm for this purpose, which (i) is computationally efficient; (ii) provides good reconstructions when the data is corrupted with additive noise which is often assumed to be Gaussian; (iii) does not employ a small-perturbations approximation, such as Born’s or Rytov’s, which restricts their scope of application. One such algorithm is proposed in this paper. Here, computational efficiency is achieved by recognising that the circular geometry of the problem translates itself into circulant matrices that are easily inverted by invoking the Fast Fourier Transform (FFT); while the desensitization of the method to corrupting noise is carried out by employing the least-squares method. Illustrative computer simulations verify the validity of the technique proposed.     

Biotransformation of benzaldehyde to L‐phenylacetylcarbinol (L‐PAC) by Torulaspora delbrueckii and conversion to ephedrine by microwave radiation

In a 5 dm³ stirred tank reactor, bioconversion of 30 g benzaldehyde by cells of Torulaspora delbrueckii yielded 22.9 g of pure L ‐phenylacetylcarbinol (L ‐PAC). Facile functional group transformation of 4.5 g of L ‐PAC to 2‐(methylimino)‐1‐phenyl‐1‐propanol by exposure to microwave irradiation for 9 min resulted in 2.48 g of product. Conversion of 4.8 g of 2‐(methylimino)‐1‐phenyl‐1‐propanol to 3.11 g of ephedrine was achieved by exposure to microwaves in a reaction time of 10 min. The identity of all the products was confirmed by ¹H NMR and FT‐IR analysis. © 2002 Society of Chemical Industry     

Comparative aroma profiles using supercritical carbon dioxide and Likens–Nickerson extraction from a commercial brand of Basmati rice

A comparative evaluation of the extraction of the aroma constituents of a popular commercial brand of Basmati rice using Likens–Nickerson extraction and supercritical fluid extraction (SFE) with carbon dioxide was carried out. SFE at 50 °C and 120 bar for 2 h provided appreciable extraction of the volatile constituents of the rice as compared with Likens–Nickerson extraction. The advantages of smaller sample size, shorter time of extraction and negligible possibility of artefacts with the SFE technique merit its use for recovery of aroma volatiles from Basmati rice. Copyright © 2003 Society of Chemical Industry     

Simulation of Agricultural Management Alternatives for Watershed Protection

The Bosque River Watershed in Texas is facing a suite of water quality issues including excess sediment, nutrient, and bacteria. The sources of the pollutants are improperly managed cropland and grazing land, dairy manure application, and effluent discharge from wastewater treatment facilities. Several best management practices (BMPs) have been proposed for pollution reduction and watershed protection. The overall objectives of this study were to demonstrate a modeling approach using Soil and Water Assessment Tool (SWAT) model to simulate various BMPs and assess their long-term impacts on sediment and nutrient loads at different spatial levels. The SWAT model was calibrated and validated for long-term annual and monthly flows at Valley Mills and for monthly sediment, total nitrogen (TN) and total phosphorus (TP) at Hico and Valley Mills monitoring locations. The BMPs including streambank stabilization, gully plugs, recharge structures, conservation tillage, terraces, contour farming, manure incorporation, filter strips, and PL-566 reservoirs were simulated in the watershed areas that met the respective practice’s specific criteria for implementation. These BMPs were represented in the pre- and post-conditions by modifying one or more channel parameters (channel cover, erodibility, Manning’s n), curve number (CN), support practice factor (P-factor), filter strip width, and tillage parameters (mixing efficiency, mixing depth). The BMPs were simulated individually and the resulting Hydrologic Response Units (HRUs), subwatershed, and watershed level impacts were quantified for each BMP. Sensitivity of model output values to input parameters used to represent the BMPs was also evaluated. Implementing individual BMPs reduced sediment loads from 3% to 37% and TN loads from 1% to 24% at the watershed outlet; however, the changes in TP loads ranged from 3% increase to 30% decrease. Higher reductions were simulated at the subwatershed and HRU levels. Among the parameters analyzed for sensitivity, P-factor and CN were most sensitive followed by Manning’s n. The TN and TP outputs were not sensitive to channel cover. This study showed that the SWAT modeling approach could be used to simulate and assess the effectiveness of agricultural best management practices.     

Studies on Cross-linked A. paniculatas (Rajgeera) Starch

Earlier studies from our laboratories on waxy A. paniculatas starch have shown it to be sensitive to mechanical shear and acidity. Cross-linking of this starch with phosphorus oxychloride at room temperature for ten min using 5 ml POCI₃ per 100 g starch improved the stability under canning conditions, low pH and also mechanical shear. Its paste clarity also improved distinctly. However, it had very poor freeze-thaw stability indicating it to be unsuitable for frozen foods. Evaluation of this starch in canned tomato soup showed it to be a useful thickener for foods processed under retort conditions.     

Utilisation of Amaranthus paniculatas (Rajgeera) Starch in Salad Dressing

Studies on utilisation of Amarantus paniculatas starch in salad dressings showed it to be more stable than corn starch. This is attributed to waxy nature of A. paniculatas starch.     

Some Properties of Amaranthus paniculatas (Rajgeera) Starch Pastes

The lysine rich high protein seeds of A. paniculatas (Rajgeera) are reported to contain 50–60% of waxy starch, concentrated in the endosperm. However its food related properties are comparatively unknown. In the present work, paste viscosity, paste clarity, freeze-thaw stability and effect of shear on the viscosity of A. paniculatas starch paste have been studied and compared to corn starch. Also included are the stability of Rajgeera starch paste under pressure cooking (30 min, 15 lb pressure) and acidic conditions (pH 6.98—1.76). Rajgeera starch was found to have a higher paste viscosity, lower paste clarity and high freeze-thaw stability than corn starch. Both Rajgeera and corn starch underwent thinning on being subjected to mechanical shear. Rajgeera starch withstood pressure cooking conditions admirably, but was found to be sensitive to acidic conditions.