A simple equivalent circuit analysis of rectangular folded-waveguide slow-wave structure

A simple yet accurate equivalent circuit model was developed for the analysis of slow-wave properties (dispersion and interaction impedance characteristics) of a rectangular folded-waveguide slow-wave structure. Present formulation includes the effects of the presence of beam-hole in the circuit, which were ignored in existing approaches. The analysis was benchmarked against measurement as well as with 3D electromagnetic modeling using MAFIA for two typical slow-wave structures operating in Ka- and Q-bands, and close agreements were observed. The analysis was extended for demonstrating the effect of the variation of beam-hole radius on the RF interaction efficiency of the device.     

Wavelet based robust sub-band features for phoneme recognition

Wavelet transform has been found to be an effective tool for the time-frequency analysis of non-stationary and quasi-stationary signals. Recent years have seen wavelet transform being used for feature extraction in speech recognition applications. In the paper a sub-band feature extraction technique based on an admissible wavelet transform is proposed and the features are modified to make them robust to additive white Gaussian noise. The performance of this system is compared with the conventional mel frequency cepstral coefficients (MFCC) under various signal to noise ratios. The recognition performance based on the eight sub-band features is found to be superior under the noisy conditions compared with MFCC features.     

Three-dimensional finite element analysis to predict the effects of SAW process parameters on temperature distribution and angular distortions in single-pass butt joints with top and bottom reinforcements

Achieving adequate top and bottom reinforcement is important to minimize angular distortions in single-pass submerged arc welded (SAW) butt joints. This is achieved in the present work by using a reusable flux-filled backing strip and proper SAW process parameters without resorting to costly distortion mitigation techniques. The butt joints were made without edge (square butts) preparation. The process was also modeled by using three-dimensional finite element analysis by incorporating the top and bottom reinforcements into the modeling. Filler material deposition was also simulated. Temperature distributions and angular distortions obtained from the modeling closely matched with the experimental values. Thus, the cost effective experimental methodology established in the present work can be utilized for minimizing angular distortions in SAW square butts. The modeling methodology adopted can be used for predicting the angular distortions in SAW square butts with top and bottom reinforcements.     

Thin layer chromatographic estimation of available lysine in dried milk powder

A rapid method for the estimation of available lysine in dried milk powder has been developed. Samples were treated with 2,4,6-trinitrobenzene sulfonic acid and then hydrolyzed with 6N HCl. The hydrolysate was purified and subjected to ascending thin layer chromatography to isolate xi-trinitophenyl lysine in pure form. The color was read at 346 nm in a specitrophotometer.     

Effects of morphine sulfate on NADPH-cytochrome c reductase and cytochrome P-450 of mouse liver microsomes

Three hr after i.p. administration of a single dose of 30 mg/kg of morphine to male mice, an increase in specific activity of NADPH-cytochrome c reductase by about 10% and the content of cytochrome P-450 by about 14% of their liver microsomes was observed.Administration of 30 mg/kg of morphine, once daily,during 5 days, caused about 16% and 9% increases in specific activity of c reductase and the content of P-450 respectively. Administration of a single dose of morphine to male and female mice caused no sex-dependent differences in the specific activity of c reductase and the content of P-450. Repeated administration of morphine up to 100 mg/kg to male mice increased the specific activity of microsomal c reductase by about 70%. Repeated administration of morphine up to 55 mg/kg also increased the microsomal content of P-450 by about 22%, but with higher doses of morphine, the content of P-450 declined and finally dropped below control levels. The levels of c-reductase activity and P-450 content returned to normal levels about 2 weeks after termination of morphine administration.     

Predictive Thermal Inactivation Model for Effects and Interactions of Temperature, NaCl, Sodium Pyrophosphate, and Sodium Lactate on Listeria monocytogenes in Ground Beef

The effects and interactions of heating temperature (60 °C to 73.9 °C), salt (0.0 % to 4.5 %?w/v), sodium pyrophosphate (0.0 % to 0.5 %?w/v), and sodium lactate (0.0 % to 4.5 %?w/v) on the heat resistance of a five-strain mixture of Listeria monocytogenes in 75 % lean ground beef were examined. Meat samples in sterile filtered stomacher bags were heated in a temperature controlled waterbath to determine thermal death times. The recovery medium was tryptic soy agar supplemented with 0.6 % yeast extract and 1 % sodium pyruvate. Weibull survival functions were employed to model the primary survival curves. Then, survival curve-specific estimated parameter values obtained from the Weibull model were used for determining a secondary model. The results indicate that temperature and salt have a large impact on the inactivation kinetics of L. monocytogenes, while sodium lactate (NaL) has an impact in the presence of salt. The model presented in this paper for predicting inactivation of L. monocytogenes can be used as an aid in designing lethality treatments meant to control the presence of this pathogen in ready-to-eat products.     

Using nitrogen and carbon dioxide molecules to probe arsenic(V) bioaccessibility in soils

Highly specialized personnel and high cost are typically required for in vivo risk assessment of arsenic (As) exposure to humans in As-contaminated soils. Arsenic bioaccessibility in soils, as determined with the aid of in vitro tests, is quite variable, and its magnitude depends upon unidentified soil properties. Use of soil chemical properties is a common practice for construction of As(V) sorption and bioaccessibility models with relative success. We propose a novel As(V) bioaccessibility model, which was tested on 17 soils. The model includes only two parameters characterizing surface properties of soils that are readily determined from N2- and CO2-based specific surface areas (SSAs), and total organic carbon (OC) content. We found that N2 and CO2 molecules act as As(V) "surrogates", probing easily accessible and relatively difficult to access soil porosity, respectively. Three interrelated linear models were constructed using two terms (CO2/N2-based SSAs and OC) that were significant (p <0.001) in explaining 51 and 95% of the variability observed in As(V) sorption and bioaccessibility, respectively. The proposed models successfully predicted bioaccessible As concentrations for 4 out of the 5 soils that were not included in the bioaccessibility models, reaching RMSE values of < or =10%.     

Microwave puffing: Determination of optimal conditions using a coupled multiphase porous media - Large deformation model

Increased interest in microwave puffing is due to its ability to obtain low-fat and ready-to-eat healthy products. Determination of optimal conditions for this complex process has been difficult and although several patents exist on the concept, we are yet to see any large scale commercial use. A fundamental physics based modeling approach integrated with relevant experimentation, developed in this work, is an ideal framework to understand and optimize microwave puffing. The results showed that puffing may not be successful unless carried out using an intensive heating source such as microwaves. Addition of infrared and hot air leads to better quality product whereas using forced air convection is not desirable. There is an optimum initial moisture content depending on the puffing conditions. The study provides critical guidelines to food product/process developers for successful development, control and automation of microwave puffing, thereby leading to value-added nutritious products.     

In vitro model improves the prediction of soil arsenic bioavailability: worst-case scenario

There is a strong interest in developing an in vitro arsenic (As) model that satisfactorily estimates the variability in in vivo relative oral bioavailability (RBA) measurements. Several in vitro tests have been developed, but none is universally accepted due to their limited success in predicting soil As RBA. A suite of amorphous and crystalline solid As phases were chosen, utilizing a worst-case scenario (WCS) that simulated fasting children's gastric solution chemistry. The objectives of this study were to (i) determine the effects of residence time, pH, and solid-to-solution ratio on As bioaccessibility and speciation in the in vitro gastric test; (ii) provide the fundamental basis for an optimized in vitro model constrained by the WCS; and (iii) validate the optimized in vitro test with the in vivo RBA obtained with BALB/c mice. The gastric pH was the only significant (p < 0.05) factor influencing solid As bioaccessibility. Bioaccessible As retained the oxidation state after its release from the solid into the gastric solution. The optimized in vitro model adequately predicted RBA values for a suite of solid As phases typically encountered in soils, with the exception of aluminum-based solids. This study is an excellent starting point for developing an in vitro test applicable to different As-contaminated soils.