Evaluation of surfactant-aided degumming of vegetable oils by membrane technology

The first step in the process of vegetable oil refining is degumming, in which phospholipids and mucilaginous gums are removed that otherwise result in a low-grade oil. A membrane process is remarkably simple yet potentially offers many advantages in degumming. Studies were conducted on surfactant-aided membrane degumming with soybean and rapeseed oils in a magnetically stirred flat membrane batch cell with different types of microfiltration membranes. The reduction of phospholipids in soybean oil was in the range of 85.8–92.8% during the membrane process. The phosphorus content of membrane permeates of soybean oil was in the range of 20–58 mg/kg. Crude rapeseed oil contained higher amount of nonhydratable phospholipids and hence resulted in lower reduction in phospholipids, in the range of 66.4–83.2%. Addition of hydratable phospholipids could improve the efficiency of degumming in the membrane process without using any electrolyte, resulting in improvement of quality as well as quantity of the phospholipids.     

Photocatalytic degradation of phenol in a rotating annular reactor

Batch photocatalytic degradation studies of phenol were conducted in an annular slurry reactor, to evaluate its performance under different operating and design conditions. The reactor had two concentric cylinders with the inner one rotating at specified revolutions per minute. The reactor also had provisions for aerating the slurry present in the annular gap. The inner cylinder housed the UV-lamps. The effects of catalyst loading (0–8 g/L), inner cylinder rotation speed (0–50 rpm), annular gap-width (7.5, 17.5 and 32.5 mm), initial pollutant concentration (10–50 mg/L) and mode of illumination (continuous or periodic) were studied. Light intensity received by the slurry was measured using Actinometry. Depending on the catalyst loading, annular gap-width and number of illuminated lamps the intensity values ranged from 0.58×10^?4 to 6.4×10^?4 Einsteins/L min. Under well mixed conditions, the reactor performance was found to increase with increase in catalyst loading. At low/medium annular gap width configurations, agitation induced by continuous aeration was found to provide sufficient mixing even when the inner cylinder was stationary. Rotation of the inner cylinder was required only in the high gap width configuration at high catalyst loadings. Scale-up of the reactor was investigated by increasing the gap-width of the annulus and hence increasing the quantity of feed processed. Controlled periodic illumination created by Taylor vortices did not show any improved performance over the regular continuous illumination. Modeling of reaction kinetics was investigated with different approaches and their efficacy in fitting the concentration–time trends of both the primary pollutant and the intermediates are discussed.     

Sulfonated polyether sulfone‐poly(vinylidene fluoride) blend membrane for DMFC applications

Direct methanol fuel cell (DMFC) proton exchange membranes were prepared by blending poly (vinylidene fluoride) (PVDF) with sulfonated poly(ether sulfone) (SPES). Using a diffusion cell and gas chromatographic technique, the effects of PVDF content on methanol permeability in the blended membranes were investigated. The thermal resistance and proton conductivity of the membranes were also determined by using a thermal gravimetric analysis (TGA) and an impedance analysis technique respectively. The presence of sulfonic acid groups in SPES was confirmed by Fourier transform infrared (FTIR). It was found that the methanol permeability in the blended membranes decreased with PVDF content at the expense of proton conductivity. Blended membranes show methanol permeability values much lower than that of Nafion 115, whereas the proton conductivities of the membranes are comparable with that of Nafion. The thermal stability of these blended membranes is above 250°C, which is sufficiently high for use in DMFC. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Amorphous Cobalt-Boron Alloy Electrodeposition and Dissolution

Co-B alloy has been deposited on steel from an alkaline citrate bath. Uniform deposits have been obtained in the current density range of 8–15 Adm ^?2.Cvclic voltammetric studies on platinum from this bath reveal that the cobalt citrate complexes undergo stepwise electronation with the participation of hydroxyl ions. The borates undergo reduction to boron in the alloy deposition. The hydrogen evolution reaction has been found to be hindered by cobalt and borate ions. Stripping voltammetric curves on the alloy film suggest the dissolution of cobalt from a cobalt rich phase.     

Role of Zinc (Zn) in Human Reproduction: A Journey from Initial Spermatogenesis to Childbirth

Zinc (Zn), the second-most necessary trace element, is abundant in the human body. The human body lacks the capacity to store Zn; hence, the dietary intake of Zn is essential for various functions and metabolism. The uptake of Zn during its transport through the body is important for proper development of the three major accessory sex glands: the testis, epididymis, and prostate. It plays key roles in the initial stages of germ cell development and spermatogenesis, sperm cell development and maturation, ejaculation, liquefaction, the binding of spermatozoa and prostasomes, capacitation, and fertilization. The prostate releases more Zn into the seminal plasma during ejaculation, and it plays a significant role in sperm release and motility. During the maternal, labor, perinatal, and neonatal periods, the part of Zn is vital. The average dietary intake of Zn is in the range of 8–12 mg/day in developing countries during the maternal period. Globally, the dietary intake of Zn varies for pregnant and lactating mothers, but the average Zn intake is in the range of 9.6–11.2 mg/day. The absence of Zn and the consequences of this have been discussed using critical evidence. The events and functions of Zn related to successful fertilization have been summarized in detail. Briefly, our current review emphasizes the role of Zn at each stage of human reproduction, from the spermatogenesis process to childbirth. The role of Zn and its supplementation in in vitro fertilization (IVF) opens opportunities for future studies on reproductive biology.     

Failure analysis of left barrel of an aircraft engine

This investigation analyses the failure of left barrel used in engine of an aircraft. The barrel was subjected to detailed examination using standard non-destructive and destructive testing methods in order to identify the cause of failure of left barrel. The experimental results include fractography, chemical analysis, coating analysis and optical microstructure. The investigation concludes that failure is caused by the formation of corrosion pits which act as stress raiser and fatigue has assisted in propagation of the crack.     

Magnetoelectric properties of Ni/PZT/Ni layered composite for low field applications

A composite material when placed under the external magnetic/electric fields exhibits voltage/induced magnetization is known as magnetoelectric (ME) composite. Such composite materials should have ferroelectric and ferro/ferri magnetic phases as constituents. The magnetoelectric output is exhibited as a product property. Magnetoelectric composites are being used for variety of applications including resonators, filters, phase shifters, optical isolators, actuators and magnetic field sensors. Metal/ferroelectric/metal magnetoelectric composite using Ni and PZT as constituent phases has been fabricated in 2-2 composite pattern to study its product property. The paper presents magnetoelectric studies of Ni/PZT/Ni composite using low dc magnetic field magnetoelectric set-up. Using this ME set-up ME output of Ni/PZT/Ni composite is studied as a function of dc magnetic field. The results were analyzed to identify the useful magnetic field (dc and ac) range in which Ni/PZT/Ni sensor can be utilized for applications.     

Structural,optical and magnetic properties of nanocrystalline Zn0.9Co0.1O-based diluted magnetic semiconductors

With a view to understand the influence of nano size on various properties of cobalt-doped ZnO-based diluted magnetic semiconductors, a series of materials were prepared by the citrate gel route. The phase and morphology studies have been carried out by X-ray diffraction and transmission electron microscopy, respectively. All the samples of the present investigation are found to have hexagonal wurtzite structure and crystallite sizes are found to vary from 25 nm to 65 nm. From the optical absorption measurements it has been observed that upon doping with cobalt, the energy band gap is found to shift towards lower energy side (red shift) while it shifts towards higher energy side (blue shift) when the crystallite size is increased continuously. It has been observed from the XPS results that oxidation state of Cobalt is +2 and that the difference in binding energies of Co 2p_3/2 and Co 2p_1/2 is found to increase continuously with increasing crystallite size. Finally, all the samples are found to exhibit room temperature ferromagnetism and the specific magnetization decreases with increasing crystallite size.