Modification of Tefzel film through graft copolymerization

The graft copolymerization of styrene (st) and methacrylonitrile (MAN) onto Tefzel film in aqueous media by the preirradiation method has been studied. In order to follow the effect of preswelling of the backbone polymer, grafting was attempted onto preirradiated Tefzel film and monomer preswollen, preirradiated Tefzel film. Optimum conditions pertaining to maximum percentage of grafting of st and MAN have been evaluated. Grafting onto preswollen, preirradiated Tefzel film displayed better results. The effect of different alcohols of increasing chain length on the percentage of grafting of st and MAN was also studied. Graft copolymerization of st showed an increase, while grafting with MAN exhibited a decrease, in the percentage of grafting in the presence of alcohols as compared to that obtained in the aqueous medium. Characterization of the graft copolymers was made by IR and thermogravimetric studies. Tefzel‐graft‐polystyrene showed improved thermal stability while the MAN grafted onto preswollen, preirradiated Tefzel film produced graft copolymer with poor thermal stability. Copyright © 2004 Society of Chemical Industry     

Effect of secondary terms on axisymmetric vibration of circular plates

Summary Free transverse vibration of a circular plate is considered by assuming the displacement components as an infinite series in the thickness coordinate. The analysis is done by retaining only the first two terms in each series. The equations of motion are derived by Hamilton's energy principle and the solutions are obtained in terms of Bessel functions. Numerical results are compared with the classical and shear theories which are particular cases of the present theory.     

Acousto-optic tunable filter sidelobe analysis and reduction with telecentric confocal optics

The acousto-optic tunable filter (AOTF) has optical sidelobes that are due to the acoustic field produced by the transducer. These sidelobes were analyzed by wave-vector phase matching between the optical and acoustic fields, which correlated with measurements made with a TeO2 AOTF. A white-light point source was filtered and imaged, showing reasonably large and slowly decreasing sidelobes covering a large spectral range. This effect reduces the image quality of an AOTF system by producing faint secondary images of bright objects. The image quality can be improved with a telecentric confocal optical arrangement in which the angular shift of the sidelobes is greatly reduced, producing a much sharper image. This effect was also demonstrated experimentally with the point source.     

Taxonomic importance of spore morphology in Thelypteridaceae from Northern Pakistan

Spore morphology of Thelypteridaceae species growing in Malakand Division, Northern Pakistan, was studied using both light microscopy and scanning electron microscopy. The taxa are Christella dentata and Glaphyropteridopsis erubescens in the subfamily Thelypteridoideae, and Phegopteris connectilis, Pseudophegopteris pyrrhorhachis, and Pseudophegopteris levingei in the subfamily Phegopteridoideae. The studied species exhibit differences in spore size, exospore thickness, color, and ornamentation. Spores of the studied species are monolete and medium‐sized, and shape is ellipsoidal in both polar and equatorial views. The average measurement of the polar diameter ranges from 27 μm to 31 μm, whereas in the equatorial direction it varied from 20 μm to 40 μm. The exospore thickness ranges from 1.2 μm to 2.4 μm. Reticulate, laevigate with microgranules, cristate, and coarsely echinate surface ornamentation are observed among the species. Multivariate analysis including unweighted pair group method with arithmetic mean and principal component analysis was used for the grouping and discrimination of species and genera.     

Solar map of India under clear sky conditions

This paper focusses on generation of solar irradiation map under clear sky conditions using r.sun model. Direct Irradiation, diffuse irradiation and global irradiation maps are plotted using programme which was developed in C language. This programme calculates different components of solar irradiation using clear sky model (r.sun). Further Surfer software was used to plot different irradiation maps. All three values (Direct Irradiation, Global Irradiation and Diffuse Irradiation) were compared by IMD values for performing statistical analysis i.e. Mean Bias Error (MBE), Root Mean Square Error (RMSE) and standard deviation. MBE was found within ±10%, RMSE lies within <20% and standard deviation was found to have very low value which indicated good fitting between model results and calculated values. Therefore the r.sun model is good model and can be used for computing solar irradiation for India.     

Combinatorial design of calcium meta phosphate poly(vinyl alcohol) bone-like biocomposites

The incidence of degenerative diseases and the ageing population have added to the growing demand for bone grafts. Although autologous bone continues to be the gold standard, limited yield and potential morbidity of the donor site pose considerable challenges. Currently, clinically used synthetic grafts based on calcium phosphates are mechanically brittle and not compliant hence composite scaffolds are expected to be provide viable solutions. In this study we report composites of calcium meta phosphate-poly (vinyl alcohol) with tunable mechanical properties, low swelling and excellent biocompatibility. The elastomeric nature of the composites resist brittle fracture and the scaffolds can be easily shaped to the bone defect by the surgeon. Testing on bone plug shaped specimens of the scaffolds, exhibited superior mechanical properties compared to currently commercially available bone plugs with additional advantages being the ability to increase porosity without compromising properties in compression and degree of swelling, which make these composites promising synthetic alternatives for bone grafts and bone tissue engineering.     

A Secure Stop and Wait Communication Protocol for Disturbed Networks

Wireless Personal Communications - Secure data communication is the need of hour today specifically when the wireless communication channel is insecure. We are proposing a protocol which can be...     

µBIGMSA-Microservice-Based Model for Big Data Knowledge Discovery: Thinking Beyond the Monoliths

Wireless Personal Communications - Enterprise thrives on software applications that are built to fulfil the core business requirements. A single business application can offer a cluster of...     

Capability of DICE Circuit to Withstand Ionizing Radiations

Memory devices continue to be an irreplaceable part of most semiconductor circuits. This is expected to continue to rise in the coming years. Thus, there is a need to incorporate radiation hardness in all memory elements. There are numerous techniques to make a circuit immune to radiations at processing level, circuit level or design level. One of the most accepted methods of achieving resilience to radiations at design level is DICE (Dual Interlocked Storage Cell). The efficiency and range of operation of DICE structure can be improved through various factors. Sizing of transistors as well as pulse width and amplitude of striking pulse of radiation are key parameters in determining successful circuit operation. Effect of varying these parameters on the circuit operation is studied with the help of simulation results. The self restoring logic in the design has a certain threshold after which the circuit is unable to regain its original value.

     

Nutrient composition of tomato products prepared using tomato grown under sodic condition with gypsum and farmyard manure treatment

BACKGROUND: The use of sodic water for crop irrigation decreases the availability of nutrients such as nitrogen, calcium, magnesium and zinc to plants and harms crop yield and quality. Crops irrigated with sodic water have been utilised in various product formulations. Gypsum and farmyard manure (FYM) are known to provide good soil amendment under sodic water irrigation. This research was therefore conducted to study the variation in nutrient composition of tomato products prepared from tomatoes irrigated with canal water (control) and those irrigated with sodic water treated with gypsum and FYM at two levels, i.e. 50% neutralisation of sodicity (G₁F₂) and complete neutralisation of sodicity (G₂F₂). RESULTS: The contents of protein, fat, crude fibre, ash, carbohydrate and total soluble sugars in three types of tomato product were in the ranges 1.08–1.68, 0.20–0.31, 0.43–1.07, 0.83–1.06, 6.17–7.22 and 2.32–4.81 g kg^?1 respectively. Tomato products prepared from tomatoes irrigated with G₁F₂‐treated water contained significantly (P < 0.05) less protein, fat, crude fibre, dietary fibre, calcium, magnesium, phosphorus, potassium, iron, zinc and sulfate but more ash, carbohydrate, total soluble sugars, oxalic acid, polyphenols, sodium, chloride and bicarbonate than those prepared from tomatoes irrigated with canal water and G₂F₂‐treated water. CONCLUSION: The results showed that tomato crops irrigated with sodic water treated with gypsum and FYM to varying extent were effective in maintaining and improving the nutrient composition of various tomato products. Copyright © 2009 Society of Chemical Industry