3D study of temperature drop behavior of subsonic rarefied gas flow in microchannel

3D Numerical study of temperature variation for subsonic rarefied gas flow in a microchannel is carried out using an in-house MPI-based parallelized DSMC code. The temperature drop in the microchannel decreases with an increase in the aspect ratio whereas it increases with an increase in the pressure ratio, the cross-aspect ratio (CAR), and the Knudsen number. 3D and 2D simulations results are compared and effect of the CAR and Knudsen number are brought out. Finally, a correlation that predicts the temperature drop is formulated along with a list of conditions that ensures a near isothermal flow.     

Probiotics: An emerging food supplement with health benefits

Probiotics are among the important functional foods. They comprise approximately 65% of the world functional food market. Probiotic products are foods, which improve intestinal microflora and support good health of the consumer. The live bacteria present in the probiotic products are lactic acid bacteria, including Lactobacilli, Bifidobacteria and Enterococci. Apart from health claims and maintenance of intestinal microflora, they protect against infections, alleviate lactose intolerance, reduce blood cholesterol levels and also stimulate the immune system. The interactive research between physiology, microbiology, food technology and molecular biology followed by clinical trials may produce a multi-functional probiotic strain for human consumption.     

Metabolomics-assisted biotechnological interventions for developing plant-based functional foods and nutraceuticals

Today, the dramatic changes in types of food consumed have led to an increased burden of chronic diseases. Therefore, the emphasis of food research is not only to ensure quality food that can supply adequate nutrients to prevent nutrition related diseases, but also to ensure overall physical and mental-health. This has led to the concept of functional foods and nutraceuticals (FFNs), which can be ideally produced and delivered through plants. Metabolomics can help in getting the most relevant functional information, and thus has been considered the greatest –OMICS technology to date. However, metabolomics has not been exploited to the best potential in plant sciences. The technology can be leveraged to identify the health promoting compounds and metabolites that can be used for the development of FFNs. This article reviews (i) plant-based FFNs-related metabolites and their health benefits; (ii) use of different analytic platforms for targeted and non-targeted metabolite profiling along with experimental considerations; (iii) exploitation of metabolomics to develop FFNs in plants using various biotechnological tools; and (iv) potential use of metabolomics in plant breeding. We have also provided some insights into integration of metabolomics with latest genome editing tools for metabolic pathway regulation in plants.     

Effect of conventional and microwave sintering on the properties of yttria alumina garnet-dispersed austenitic stainless steel

The current study examines the effect of heating mode, temperature, and varying yttria alumina garnet (YAG) addition (5 and 10 wt pct) on the densification and properties of austenitic (316L) stainless steel. The straight 316L stainless steel and 316L-YAG composites were heated in a radiatively heated (conventional) and 2.45 GHz microwave sintering furnace. The compacts were consolidated through solid state as well as supersolidus sintering at 1200 °C and 1400 °C, respectively. Both 316L and 316L-YAG compacts couple with microwaves and heat to the sintering temperature rapidly (∼45 °C/min). The overall processing time was reduced by about 90 pct through microwave sintering. As compared to conventional sintering, compacts sintered in microwaves exhibit higher densification and finer microstructure but no corresponding improvement in mechanical properties and wear resistance. This has been correlated to elongated, irregular pore structure in microwave-sintered compacts.     

Injection-molding process control—A review

This paper reviews control strategies employed in the injection-molding process. For clarity, the controlled variables have been categorized into all-phase control, phase-dependent control, and cycle-to-cycle control. All-phase control includes variables that must be monitored and controlled at all times; i.e., in all the phases. Control of variables that are triggered during a specific phase are discussed under phase-dependent control. In cycle-to-cycle control, previous data are used to predict future trends and take appropriate corrective actions, The cyclic, dynamic, and unsteady state nature of the injection-molding process is discussed with respect to the conventional proportional-integral (PI) and proportional- integral-derivative (PID) controllers as well as the more advanced control schemes such as self-tuning control, optimal control, and statistical process control. Suggestions involving specific advanced control schemes and recommendations for future research in injection-molding process control also are made.     

The inhibition of corrosion and hydrogen embrittlement of AISI 410 stainless steel

A study was carried out on the inhibition of corrosion and hydrogen embrittlement of AISI 410 stainless steel by two organic inhibitors, namely benzotriazole and benzonitrile. Tensile testing, scanning electron microscopy, weight loss measurements and potentiodynamic polarization were the techniques used for this study. Tensile tests showed that 410 steel is highly susceptible to hydrogen stress cracking. Scanning electron microscopic observations of fracture surfaces showed a brittle quasi-cleavage type of failure when the steel was hydrogen charged from 0.5m H₂SO₄. Both inhibitors reduced hydrogen induced ductility loss though the fracture mode was unaltered. They showed increasing inhibition efficiencies for corrosion as well as cathodic hydrogen evolution as their concentration in H₂SO₄ increased from 3.9×10^–5 m to 8.4×10^–3 m. Benzonitrile was found to be a more efficient inhibitor than benzotriazole for AISI 410 stainless steel exposed to 0.5m H₂SO₄.