Relating blow moldability to large amplitude oscillatory shear behavior

The large amplitude oscillatory shear test has been used to discriminate subtle differences in nonlinear viscoelasticity between two high density polyethyene blow molding resins with different processability. Structural network theory was used to explain the subtle differences in terms of entanglement kinetics with remarkable accuracy. The resin with better shape retention characteristics in programmed parison blow molding was found to have a higher kinetic rate constant for molecular re-entanglement.     

Properties and pervaporation separation of hydroxyl‐terminated polybutadiene‐based polyurethane/poly(methyl metharcylate) interpenetrating networks membranes

Hydroxyl‐terminated polybutadiene (HTPB), 4,4′‐dicyclohexyl methane diiscyanate (H₁₂MDI), and 1,4‐butane diol are used to synthesize polyurethane (PU) solutions by two‐stage process. Interpenetrating networks (IPNs) of HTPB‐based PU and poly(methyl methacrylate) (PMMA) with HTPB/MMA (wt/wt % ratio) = 2.0, 1.5, 1.0, 1.5, 0.8, and 0.6, which are designated as IPN1 to IPN5, respectively, are synthesized by sequential polymerization technique. Thermal properties, tensile strength, and contact angle of membranes increase with the increase of MMA content, while the elongation of membranes show the reverse trend. Characterization of membranes are investigated by C?C/C?O absorption ratio and infrared absorption frequency shiftment. These PU and IPN membranes are used for the separation of ethanol/water and isopropanol/water solution by pervaporation test. IPN3 membrane possesses the largest pervaporation permeability and the separation factor. The pervaporation results of ethanol/water feed has the same trend as that of isopropyl alcohol (IPA)/water solution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Accurate rotor flux orientation technique for indirect rotor flux oriented control of induction motor drives

Abstract

In this paper, a novel detuning index is first proposed for indicating the proper timing required to correct the rotor time constant of indirect rotor flux oriented controlled single‐cage induction motor drives. This index can faithfully reflect the influence of rotor resistance changes as well as rotor flux changes. It also reduces greatly the number of rotor time constant estimations in practical applications. The theoretical basis of the index and the physical meaning are described in the paper in detail. Based on the proposed index, an on‐line rotor time constant estimator is also proposed to make corrections. Only existing available quantities of the closed loop controller are used for calculating the estimated rotor time constant accurately. Both simulation and experimental results verify the effectiveness of the proposed rotor flux orientation technique. It is seen that the proposed rotor flux orientation technique is suitable for practical applications.     

Low-Temperature Processing of PZT Thick Film by Seeding and High-Energy Ball Milling and Studies on Electrical Properties

Lead zirconate titanate thick film with molecular formula PbZr_0.52Ti_0.42O₃ (PZT) was prepared by a modified conventional sol–gel method through seeding and high-energy ball milling, resulting in perovskite phase formation at lower temperatures. The ball-milling time was optimized by keeping the seed particle loading (5 wt.%) constant in the sol–gel solution. This methodology helped in reduction of the crystalline phase formation temperature to 300°C, which is much lower than that reported in the literature (450°C). The well-established perovskite phase was confirmed by x-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) of PZT films revealed uniform and crystalline microstructure. Film prepared by this methodology showed higher spontaneous polarization (2.22 μC/cm²), higher capacitance (1.17 nF), and low leakage current density (18 μA/cm²). The results obtained from ferroelectric characterization showed a strong correlation with the XRD and SEM results.     

Highly permeable and selective pore-spanning biomimetic membrane embedded with aquaporin Z

A highly permeable yet highly selective pore-spanning biomimetic membrane embedded with aquaporin Z is molecularly designed and constructed via a combination of pressure-assisted vesicle adsorption and covalent-conjugation-driven vesicle fusion on a porous support. This approach represents a significant breakthrough in the architecture of biomimetic membranes embedded with aquaporin in a planar form.     

Prediction of the femoral neck-shaft angle from the length of the femoral neck

The purpose of this in vitro study was to compare the effects of the Sensonic. Oral-B Braun mechanical and Oral-B manual toothbrushes upon the morphology and cellular integrity of Treponema denticola. This spirochete was chosen because of its frequent isolation from active lesions of inflammatory periodontal disease and its pathogenic potential. T. denticola, strain ATCC 33421, was grown in an anaerobic nitrogen rich atmosphere in enhanced 1186 mycoplasma broth. 160, 5-ml aliquots of cultured microbes were assigned to 1 of 3 brushing treatment groups and a control group. Samples were further divided into 4 groups of 10 samples each and assigned to one of 4 brushing exposure times: 15, 30, 45, and 60 seconds. After treatment, 0.2 ml of each sample was applied to a millipore filter and examined by SEM. Intact microbes were counted from 10 non-overlapping fields at 4500x. Remaining treated samples were pelleted and examined by TEM. A statistically significant reduction of intact microbes for the Sensonic treatment group at each exposure time was found when compared to Oral-B Braun, Oral-B manual, and non-treated controls. TEM examination of Sensonic treated samples revealed separation of the outer membrane at lower exposure times and only cellular debris after exposures of 45 and 60 s. These results suggest that exposure to the sonic frequency generated by the Sensonic toothbrush is capable of severely disrupting the structural integrity of T. denticola.     

Nucleotide sequence of ToxPK1 gene from Toxoplasma gondii

We report here for the first time a complete nucleotide sequence (6.8 kb) of a protein kinase gene (ToxPK1) from the obligate intracellular protozoan parasite of man, Toxoplasma gondii. This gene comprising putatively of 9 exons and 8 introns forms the Toxoplasma gene with the largest number and size of introns reported so far. The predicted protein with 508 amino acids contains the 15 invariant residues as well as the characteristic motifs specific to protein serine/threonine kinases. Homology-based computational comparisons suggested that TOXPK1 belongs to or closely resembles the SNF1 subfamily of protein-serine/threonine kinases. Based on the functions of SNF1 homologs in other organisms and our RT-PCR results, it is likely that TOXPK1 may be transiently expressed to up-regulate glycogen biosynthesis during the development of tachyzoites into bradyzoites.     

Evaluation of urban sprawl pattern in the tribal-dominated cities of Jharkhand state,India

The patterns of urban sprawl over a 20-year period presented in the study indicate unplanned development in the urban agglomerations of Ranchi, Jamshedpur and Dhanbad. The visual interpretation of Landsat (1986, 1991, 1996 and 2001) and IRS-P6 (2005) was used to map land use/land cover and analyse urban sprawl. The saturation of urban areas within municipal limits, along with pressure from the growing population, resulted in the densification of the core urban areas within Dhanbad and Jamshedpur. Comparatively, Ranchi exhibited a very high rate of built-up growth with a reducing population density, indicating a low density of built-up development. The development of built-up land at the expense of agricultural land in Ranchi Urban Agglomeration indicates poor land-transformation practices. An area of 103.6 km² (165.66% growth) was transformed to built-up land in these cities during 1986–2005. Any future built-up development of these agglomerations should involve the use of the government city development plan.