Model reduction and process control of thermomechanical behaviour of non-linear material deformation

This paper describes a design procedure for metal forming processes by using the controllable subspace of the full system. The velocity profile of the moving die is designed using the reduced order system. The metal forming processes are simulated using non-linear finite element methods based on the rigid viscoplastic flow formulation. The balanced model reduction technique is applied to reduce the full state space model to a reduced order model that retains the controllable subspace of the thermomechanical system. The linear quadratic regulator theory with output tracking is used as an off-line design tool to design the die velocity schedule. The process design is carried out to maintain the strain rate of the critical portion of the billet at a desired value. The procedure for designing the process parameters is demonstrated using two case studies.     

Fish protein hydrolysates: Proximate composition,amino acid composition,antioxidant activities and applications: A review

The fish processing industry produces more than 60% by-products as waste, which includes skin, head, viscera, trimmings, liver, frames, bones, and roes. These by-product wastes contain good amount of protein rich material that are normally processed into low market-value products, such as animal feed, fish meal and fertilizer. In view of utilizing these fish industry wastes, and for increasing the value to several underutilised fish species, protein hydrolysates from fish proteins are being prepared by several researchers all over the world. Fish protein hydrolysates are breakdown products of enzymatic conversion of fish proteins into smaller peptides, which normally contain 2–20 amino acids. In recent years, fish protein hydrolysates have attracted much attention of food biotechnologists due to the availability of large quantities of raw material for the process, and presence of high protein content with good amino acid balance and bioactive peptides (antioxidant, antihypertensive, immunomodulatory and antimicrobial peptides).     

Ionic liquid assisted one step green synthesis of Au–Ag bimetallic nanoparticles

Au–Ag bimetallic nanoparticles have been fabricated by one-step simple electrochemical deposition method using ionic liquid as green electrolyte (1-butyl-3-methylimidazolium tetrafluoro borate). Fabricated Au–Ag bimetallic nanoparticles have been characterized using cyclic voltammetry (CV), FE-SEM, UV–vis spectroscopy, and X-ray diffraction (XRD) studies. The electrodeposited Au–Ag bimetallic nanoparticles were found in the size range of 16–30 nm, respectively. This type of Au–Ag bimetallic nanoparticles could be directly applied for the optoelectronic and biosensing applications.     

Synthesis and characterization of poly(3‐octylthiophene)/single wall carbon nanotube composites for photovoltaic applications

In situ polymerization of P3OT with SWCNT is carried out in the presence of a FeCl₃ oxidant in a chloroform medium. The characterization of the composites is performed with FTIR, Raman, ¹H‐NMR, UV–Vis, PL spectroscopy, XRD, SEM, TEM, and conductivity measurements. The change (if any) in CC symmetric and antisymmetric stretching frequencies in FTIR, the shift in G band frequencies in Raman, any alterations in λ_max of UV–Vis and PL spectroscopic measurements are monitored with SWCNT loading in the polymer matrix. ¹H‐NMR confirms the wrapping of the polymer on to the SWCNT indicating lack of mobility. The work function values and the optical band gap values also support this view. The in situ polymerization procedure of the donor polymer molecules and the acceptor carbon nanotubes has resulted in enhanced dispersibility and stability of the composites in organic solvents. However, the principal focus of the study is to understand the interaction between the polymer and the SWCNTs, as the interface plays an important role in its application in the photovoltaic cells. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of TiO2 paste using poly(vinylpyrrolidone) for dye sensitized solar cells

The surface morphology of titanium oxide (TiO₂) films as a photoanode in dye sensitized solar cells plays a vital role in converting light to electricity. Therefore, TiO₂ films were prepared using TiO₂ paste with different compositions of poly(vinylpyrrolidone) (PVP) as a binder to optimize their physico-chemical properties. The paste was prepared with commercial TiO₂ powder mixed with acetylacetone, PVP, 4-octylphenol polyethoxylate, acetic acid and ethanol. The chemical composition remains the same for all pastes except PVP. The quantity of the PVP was optimized in such a way that it provides a thick film with a good network connection. The impact of the quantity of PVP in the TiO₂ paste was analyzed. The prepared TiO₂ film structure was characterized by X-ray diffraction. The surface morphology was analyzed by scanning electron microscopy. The electrochemical performance of the prepared TiO₂ as a photoanode was also investigated. Among the four different photoanodes, the cells fabricated with a TiO₂ film prepared with 0.4 g of PVP exhibited the highest power conversion efficiency of 6.77%, short-circuit photocurrent density and open circuit voltage of 12.38 mA/cm² and 0.77 V, respectively.     

Zinc and iron contents and their bioaccessibility in cereals and pulses consumed in India

Several cereals and pulses commonly consumed in India were screened for zinc and iron contents and their bioaccessibility in the same was determined by equilibrium dialysis employing an in vitro simulated digestion procedure. Zinc content of cereals ranged from 1.08 mg/100 g in rice to 2.24 mg/100 g in sorghum. Zinc content of pulses was between 2.03 mg/100 g (whole chickpea) and 2.68 mg/ 100 g (decorticated chickpea). Iron content of cereals ranged from 1.32 mg% in rice to 6.51 mg% in sorghum, while that of pulses ranged from 3.85 mg% in decorticated green gram to 6.46 mg% in black gram. Dialyzability of zinc from pulses (27–56%) was generally higher than that from cereals (5.5–21.4%). Dialyzabilities of iron were almost similar from both cereals and pulses examined and were 4.13–8.05% in cereals and 1.77–10.2 % in pulses. A significant negative correlation between inherent phytate content and zinc dialyzability value was inferred in the case of pulses. Phytic acid content of the cereals had a significant negative influence on iron dialyzability. Inherent calcium had a negative influence on zinc dialyzability in cereals. Tannin did not have any significant influence on zinc or iron dialyzabilities from cereals and pulses. While both insoluble and soluble fractions of the dietary fibre generally interfered with zinc dialyzability, the insoluble fraction alone had this effect on iron dialyzability. The lower collective negative influence of the inherent factors on zinc dialyzability from pulses is consistent with their higher concentrations in these grains, relative to cereals. The negative correlation of inherent phytic acid with zinc and iron dialyzabilities was supported by enhanced dialyzabilities of these minerals upon partial removal of phytate from the grains by treatment with fungal phytase.     

Effect of black tea on histological and immunohistochemical changes in pancreatic tissues of normal and streptozotocin‐induced diabetic mice (Mus musculus)

The aim of the present study is to evaluate the effect of hot water extract of black tea in regenerating β cells in streptozotocin‐induced diabetic mice. Light microscopic examination of pancreatic sections of streptozotocin‐induced diabetic mice showed the acinar cells to be small, shrunken, and with deteriorated β cells. The dose of streptozotocin not only altered the function of β cells but also damaged the acinar region. The changes in acinar cells were coarsening of endoplasmic reticulation suggesting alteration in their secretory function. The control pancreatic tissue showed well‐defined granulated islets and dark β cells when stained with chrome hematoxylin and phloxine. Interestingly, pancreatic sections of diabetic mice fed with black‐tea extract showed regeneration of β cells and acinar region appeared normal with increased numbers of β cells. To understand the probable mechanism of action of black‐tea extract, we analyzed inducible nitric oxide synthase (iNOS) expression by immunohistochemistry and the results showed an increased iNOS levels in streptozotocin‐induced diabetic pancreas, and such high iNOS levels were inhibited in black‐tea extract treated mice. According to histological results obtained, it can be concluded that the black‐tea extract helps in regeneration of damaged pancreas and protects pancreatic β cells by its antioxidant action against nitrosative stress in streptozotocin‐induced diabetes. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.     

Effect of thermal boundary layer on radiative heat transfer from combustion plasma

The effect of thermal boundary layer on radiative heat transfer considering nongray nonisothermal plasma has been calculated for potassium seeded watergas combustion plasma. The effect of combustion species concentration and seed concentration on radiative flux under the equilibrium flow and frozen flow condition has been studied. It has been estimated that reduction in radiative flux due to cold boundary layer may be upto 25%.