Simple tests for rapid assessment of the quality of raw milk.

Simple and inexpensive tests are described for rapid qualitative assessment of the microbiological quality of raw milk. These tests included the monitoring of dissolved oxygen levels and changes in the color of raw milk with time in a slightly modified methylene blue test using 16 ppm of dye concentration. The initial bacterial population in raw milk determined by standard plate count could be estimated with coefficients of determination (r2) of about 0.697 and 0.613 from the respective normalized voltage outputs of the dissolved oxygen probe and light-sensing probes at selected time intervals in less than 1 h. However, a comparison of experimental and estimated initial bacterial populations in raw milk showed correlation coefficients (r) of about 0.754 and 0.616 for the dissolved oxygen probe and light-sensing probe, respectively. These results clearly indicated the potential and need for improving such empirical models for grading raw milk with both types of probes.     

Absolute movement of energy levels in junctions formed by dissimilar materials

We propose a method to determine the absolute location of energy levels when electrical contact is made between two dissimilar materials. The conventional method of determining the energy levels is correct only as a limiting case when the number of electrons in one sample greatly exceed that in the other.     

Liquid Phase Oxidation of p-Cresol over Cobalt Saponite

Liquid phase oxidation of p-cresol was carried out over a Co-saponite catalyst in a temperature and pressure range of 333–393 K and 20–827 kPa, respectively in n-propanol. Co-saponites with varying cobalt content (5–30%) were prepared and screened among which 13% Co-saponite gave the highest conversion of 92% of p-cresol with 92% selectivity to p-hydroxybenzaldehyde without formation of any non-oxidation products.     

Reliability assessment of passive containment isolation system using APSRA methodology

In this paper, a methodology known as APSRA (Assessment of Passive System ReliAbility) has been employed for evaluation of the reliability of passive systems. The methodology has been applied to the passive containment isolation system (PCIS) of the Indian advanced heavy water reactor (AHWR). In the APSRA methodology, the passive system reliability evaluation is based on the failure probability of the system to carryout the desired function. The methodology first determines the operational characteristics of the system and the failure conditions by assigning a predetermined failure criterion. The failure surface is predicted using a best estimate code considering deviations of the operating parameters from their nominal states, which affect the PCIS performance. APSRA proposes to compare the code predictions with the test data to generate the uncertainties on the failure parameter prediction, which is later considered in the code for accurate prediction of failure surface of the system. Once the failure surface of the system is predicted, the cause of failure is examined through root diagnosis, which occurs mainly due to failure of mechanical components. The failure probability of these components is evaluated through a classical PSA treatment using the generic data. The reliability of the PCIS is evaluated from the probability of availability of the components for the success of the passive containment isolation system.     

Effects of material microstructure on blunt projectile penetration of a nickel-based super alloy

Engine fan-blade containment systems, required in many aviation applications, are frequently manufactured from high-temperature superalloys, such as Inconel-718. As in many other applications, there is an incessant desire to maximize mechanical properties of the containment component while minimizing its weight. However, a thorough understanding of the impact behavior of the various heat treatments of these alloys in engine fan-blade containment applications does not currently exist. Due to this incomplete state of knowledge, a combined experimental–analytical investigation was conducted at CWRU in collaboration with researchers at NASA GRC. As a part of this investigation, thin plates of Inconel-718, in both annealed and precipitation hardened conditions were subjected to semi-quantitative high speed penetration tests. Dynamic compression and top hat shear localization tests using a split Hopkinson pressure bar were also conducted as part of a more fundamental assessment of this material. The measured dynamic material response in compression was used to develop a material model which adequately described the dynamic behavior of IN-718 in both the annealed and precipitation hardened states. Moreover, a transient large deformation thermo-elastic-viscoplastic finite element code is used to understand the local thermo-mechanical fields during impact in both the annealed and precipitation hardened microstructures. The results from these studies show that the annealed material demonstrated superior penetration resistance when compared with the hardened material. The annealed IN-718 absorbed more energy through multiple deformation modes and did not show any susceptibility to shear localization, which was in contrast to the precipitation hardened material. These results, therefore, suggest a precipitation hardened condition may not be optimal for impact energy absorption applications, such as, in engine fan-blade containment.     

Sulfonated poly(arylene ether sulfone) nanocomposite electrolyte membrane for fuel cell applications: A review

Polymer electrolyte membrane (PEM) fuel cells are considered a promising technology for generating power with water as a byproduct. Recently, sulfonated poly(arylene ether sulfone) (SPAES) has emerged as a most suitable alternative for PEM applications because of its high proton conductivity, high CO tolerance, and low fuel crossover. However, the existing SPAES polymeric membrane materials have poor chemical reactivity, mechanical processability, and thermal usability. Thus, the effects of mixing inorganic nanomaterials with SPAES polymers on proton conductivity, power density, fuel crossover, thermal and chemical stability, and durability are discussed in this review. Further, the progress in preparation methods and fuel cell characteristics by the addition of silica, clay, heteropolyacids (HPA), and carbon nanotubes (CNTs) in polymer membrane materials for PEM applications is also discussed.     

Comparison of adhesion characteristics of common dairy sporeformers and their spores on unmodified and modified stainless steel contact surfaces

The attachment of aerobic spore-forming bacteria and their spores to the surfaces of dairy processing equipment leads to biofilm formation. Although sporeformers may differ in the degree of attachment, various surface modifications are being studied in order to develop a surface that is least vulnerable to attachment. This study was conducted to compare the extent of adhesion of spores and vegetative cells of the thermotolerant sporeformer Bacillus licheniformis and the high-heat-resistant sporeformers Geobacillus stearothermophilus and Bacillus sporothermodurans on both native and modified stainless steel surfaces. We studied the effect of contact surface and cell surface properties (including surface energy, surface hydrophobicity, cell surface hydrophobicity, and zeta potential) on the adhesion tendency of both types of sporeformers and their spores. Attachment to native and modified (Ni-P-polytetrafluoroethylene, Ni-P-PTFE) stainless steel surfaces was determined by allowing interaction between the respective contact surface and vegetative cells or spores for 1 h at ambient temperature. The hydrophobicity of vegetative cells and spores of aerobic spore-forming bacteria was determined using the hexadecane assay, and zeta potential was determined using the Zeta sizer Nano series instrument (Malvern Panalytical, Malvern, UK). The results indicated a higher adhesion tendency of spores over vegetative cells for both thermotolerant and high-heat-resistant sporeformers. On comparing the sporeformers, B. sporothermodurans demonstrated the highest adhesion tendency followed by G. stearothermophilus; B. licheniformis exhibited minimal attachment on both surfaces. The tendency to adhere varied with cell surface properties, decreasing with lower cell surface hydrophobicity and higher cell surface charge. On the other hand, modifying contact surface properties for higher surface hydrophobicity and lower surface energy decreased attachment.     

Fluid properties of an unsteady MHD free stream flow over a stretching sheet in presence of radiation

Variable fluid properties with thermal radiation in an unsteady magnetohydrodynamics free stream incompressible flow over a stretching sheet has been considered. The thermal diffusivity and viscosity of the fluid varies linearly with temperature. The governing partial differential equations are moulded to ordinary differential equations using time-dependent similarity variables and the stream function. RKF technique with shooting method has been implement to find the solution numerically. In the current analysis the impact of unsteadiness, magnetic field, radiative parameter, variable fluid viscosity and thermal diffusivity parameter on heat and flow behavior with the free stream parameter have been studied. Transition point observed in the velocity profiles with an change in unsteadiness parameter and the effect of magnetic field is reduced in the presence of free stram velocity. The velocity and the temperature gradient are computed on the surface and their outcomes with different parameters have been analyzed in the results shown graphically and in tabular form.     

Effect of sprouting on physicochemical,antioxidant and flavonoid profile of onion varieties

This study investigated the impact of sprouting in four Indian onion varieties (Punjab White, Punjab Naroya, PRO‐6 and Commercial). Results showed significant (P < 0.05) increase in protein, crude fibre, ascorbic acid content, total phenol content, total flavonoid content, antioxidant activity, anthocyanin content and significant (P < 0.05) decrease in total carbohydrate, energy value and hardness due to sprouting in all the four varieties. HPLC analysis revealed irregular pattern of increase and decrease in flavonoid components. There was no particular trend observed within analysed flavonols due to sprouting in all the four varieties except with the maximum increase in quercetin (219.3–287.4 mg kg^?1), kaempferol (13.8–17 mg kg^?1), myricetin (34.6–40.9 mg kg^?1), quercetin‐3?‐glucoside (2.9–4.1 mg kg^?1) and quercetin‐4?‐glucoside (83–87.1 mg kg^?1) in case of PRO‐6 variety only. The present research work implied sprouting to be beneficial in onion as nutritional and functional potential of all the four onion varieties was improved by sprouting.