Morphology,mechanical and viscoelastic properties of nitrile rubber/epoxidized natural rubber blends

A new class of blend membranes from blends of nitrile rubber (NBR) and epoxidized natural rubber (ENR) has been prepared and their morphology, miscibility, mechanical, and viscoelastic properties have been studied. The ebonite method was used to study the blend morphology of the membranes. The morphology of the blends indicated a two‐phase structure in which the minor phase is dispersed as domains in the major continuous phase. The performance of NBR/ENR blend membranes has been studied from the mechanical measurements. The viscoelastic behavior of the blends has been analyzed from the dynamic mechanical data. An attempt was made to relate the viscoelastic behavior with the morphology of the blends. Various composite models have been used to predict the experimental viscoelastic data. The area under the linear loss modulus curve was larger than that obtained by theoretical group contribution analysis. The homogeneity of the system was further evaluated by Cole–Cole analysis. Finally, a master curve for the modulus of the blend was generated by applying the time–temperature superposition principle. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1561–1573, 2005     

A High-Speed Optical Multidrop Bus for Computer Interconnections

Signal integrity constraints of high-speed electronics have made multidrop electrical buses infeasible. This high-speed alternative uses hollow metal waveguides and pellicle beam splitters that interconnect modules attached to the bus. With 1 mW of laser power, the bus can interconnect eight modules at 10 Gbps per channel and achieves an aggregate bandwidth of more than 25 Gbytes per second with 10-bit-wide signaling paths.     

Room temperature ionic liquid,cetyl pyridinium naphthenate,supported cloud point extractive separation and ultra trace determination of copper in blood and environmental samples

A new unconventional room temperature ionic liquid, cetyl pyridinium naphthenate (CPN) was synthesized and was ascertained by IR, NMR and CHN analysis. Cloud point extraction of Cu(II) was carried out by using CPN for a synergistic enhancement effect. Triton X 100 was used as surfactant in cloud point extraction and cloud point temperature was 750 C. Quantification was carried out by FAAS. The mean recovery, enrichment factor, tolerance limit, RSD, LOD and LOQ were found to be 99.8%, 40, 1000 ppm, 0.15%, 27 ppt and 93 ppt respectively. Method was validated by analyzing natural water and blood samples.     

Short‐duration cassava genotypes for crop diversification in the humid tropics: growth dynamics,biomass, yield and quality

BACKGROUND: Short‐duration (6–7 months) cassava provides opportunities to smallholder farmers for effective utilisation of resources such as land, moisture and nutrients as well as diversification of enterprise and income. The variation in biomass production and partitioning, seasonal course of growth indices, yield, quality and nutrient uptake of ten short‐duration/early‐bulking genotypes of cassava and their impact on nutrient contents in soil in a lowland situation akin to rice fallow were examined in this study. RESULTS: Triploid 2–18 gave the highest yield (38.34 t ha^?1), followed by triploid 4‐2, Sree Vijaya, Sree Jaya and Vellayani Hraswa, which were on a par (30–32 t ha^?1). Vellayani Hraswa, Sree Vijaya and triploid 4‐2 had significantly higher tuberous root dry matter content (370–380 mg g^?1) and fairly higher starch content (270–280 mg g^?1). All genotypes except triploid 4‐2, triploid 2–18 and H‐165 had low cyanogen content (29.2–43.8 µg g^?1), well within the tolerable limit. Tuberous root dry matter and total dry matter production, crop growth rate, tuberous root bulking rate and harvest index at the last phase, number of tuberous roots, mean weight of tuberous roots and nutrient uptake showed significant positive correlations with tuberous root yield. Principal component analysis also showed a similar trend. CONCLUSION: The diploids Sree Vijaya, Sree Jaya, Vellayani Hraswa and Kalpaka are ideal for cultivation in rice fallow for food use owing to their high yield, good cooking quality and low cyanogen content. The triploids are better suited for industrial use owing to their high tuberous root dry biomass production. Copyright © 2009 Society of Chemical Industry     

Improving the Sensitivity of FAB Tandem Mass Spectrometry for PAH-DNA Adducts

Abstract

The mass spectrometric detection limits for guanine, adenine, and an adeninddimethylbenthracene adduct were greatly improved by converting the materials to pentafluorobenzyl derivatives, as well as by doing coaxial continuous flow-FAB (coaxial cf-Fast Atom Bombardment). The lowest detection limit (approximately 10 pg) was achieved when the derivatized sample was introduced by coaxial cf-FAB and the determination was by fill-scan mass spectrometry. The lowest detection limit achieved by tandem mass spectrometry was 50 pg obtained after derivatization, coaxial cf-FAB introduction and detection with an extended mass range array.     

An analytical model for a TFET with an n-doped channel operating in accumulation and inversion modes

The tunnel field-effect transistor (TFET) is an ambipolar device that conducts current with the channel in both accumulation and inversion modes. Analytical expressions for the channel potential and current in a TFET with an n-doped channel when operating in the accumulation and inversion modes are proposed herein. The potential model is derived by solving the two-dimensional (2D) Poisson equation using the superposition principle while considering the charges present in the channel due to electron or hole accumulation along with the depletion charges. An expression for the tunneling current corresponding to the maximum tunneling probability is also derived. The tunneling current is obtained by analytically calculating the minimum tunneling length in a TFET when operating in the accumulation or inversion mode. The results of the proposed potential model is compared with technology computer-aided design (TCAD) simulations for TFET with various dimensions, revealing good agreement. The potential and current in an n-type TFET (nTFET) obtained using the proposed models are also analyzed.

     

Light Extraction From Solution-Based Processable Electrophosphorescent Organic Light-Emitting Diodes

Molecular dye dispersed solution processable blue emitting organic light-emitting devices have been fabricated and the resulting devices exhibit efficiency as high as 25 cd/A. With down-conversion phosphors, white emitting devices have been demonstrated with peak efficiency of 38 cd/A and luminous efficiency of 25 lm/W. The high efficiencies have been a product of proper tuning of carrier transport, optimization of the location of the carrier recombination zone and, hence, microcavity effect, efficient down-conversion from blue to white light, and scattering/isotropic remission due to phosphor particles. An optical model has been developed to investigate all these effects. In contrast to the common misunderstanding that light out-coupling efficiency is about 22% and independent of device architecture, our device data and optical modeling results clearly demonstrated that the light out-coupling efficiency is strongly dependent on the exact location of the recombination zone. Estimating the device internal quantum efficiencies based on external quantum efficiencies without considering the device architecture could lead to erroneous conclusions     

The effect of angiotensin AT1 receptor blockade in the brain on the maintenance of blood pressure during haemorrhage in sheep

The effect of systemic or intracerebroventricular (ICV) infusion of the angiotensin AT1 receptor antagonist losartan on blood pressure during hypotensive haemorrhage was investigated in five conscious sheep. Mean arterial pressure (MAP) was measured during haemorrhage (15 mL kg-1 body wt). Losartan (1 or 0.33 mg h-1) was given to sheep by ICV, intravenous or intracarotid administration, beginning 60 min before and continuing during the haemorrhage. During control infusion of ICV artificial cerebrospinal fluid, MAP was maintained until 13.16 +/- 0.84 mL kg-1 blood loss, when a rapid reduction of at least 15 mmHg in arterial pressure occurred (the decompensation phase). ICV infusion of losartan at 1 mg h-1 caused an early onset of the decompensation phase after only 9.8 +/- 0.8 mL kg-1 of blood loss compared with control. Intravenous infusion of losartan (1 mg h-1) also caused an early onset (P < 0.05) of the decompensation phase at 10.2 +/- 1.0 mL kg-1 blood loss. This dose of losartan inhibited the pressor response to ICV angiotensin II, but not to intravenously administered angiotensin II, indicating that only central AT1 receptors were blocked. Bilateral carotid arterial administration of losartan at 0.33 mg h-1 caused an early onset of the decompensation phase during haemorrhage at 11.06 +/- 0.91 mL kg-1 blood loss (P < 0.05), which did not occur when infused by intravenous or ICV routes. The results indicate that an angiotensin AT1-receptor-mediated mechanism is involved in the maintenance of MAP during haemorrhage in sheep. The locus of this mechanism appears to be the brain.