Characterization of the uranium--2.25 weight percent niobium alloy

Barium hexaferrite/high density polyethylene composite was prepared from synthesized barium hexaferrite as matrix with 0, 10, 20, 30, 40 wt.% of high density polyethylene via a high energy planetary ball milling for 10 h. The milling products were isostatically pressed and finally sintered at 1250 °C for 1 h. Effect of HDPE content on morphology of the products were investigated using scanning electron microscope (SEM). Vibrating samplemagnetometer (VSM) analysis of single phase BaFe12O19 indicates saturation magnetization and coercivity of 52 emu/g and 4300 Oe, respectively. Visually, as the weight percent of the HDPE increases, more porous structure was observed. Moreover, the density of the sintered sampleslinearly decreased from 4.16 to 1.41 g/cm3 by increasing the amount of HDPE from 0 to 40 wt.%.

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Preparation and Characterization of Polymer Blends of Ethyl Cellulose and its Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.665.336 ◽

2013 ◽

Vol 665 ◽

pp. 336-340 ◽

Cited By ~ 1

Author(s):

Eknath Nivrtirao ◽

Basavaraja Sannakki

Keyword(s):

Activation Energy ◽

Dielectric Permittivity ◽

Polymer Blend ◽

Ethyl Cellulose ◽

Weight Percent ◽

Vinyl Pyrrolidone ◽

X Ray ◽

Poly Vinyl Pyrrolidone ◽

Different Thickness

The polymer blend of Ethyl Cellulose (EC) with Poly (vinyl) pyrrolidone (PVP) of various weight percentages at different thickness are used for measurement of dielectric permittivity, electrical conductivity and optical properties. The activation energies of the EC and its blend with PVP are obtained through measurement of dc conductivity. The samples are characterized by using X-ray diffractometer (XRD). The blends of EC with PVP in the ratio of 50:50 weight percent using FTIR over the range of wavenumber 4000-500 cm-1. Key words: Polymer Blend, XRD, SEM, FTIR, dielectric permittivity, activation energy.

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Characterization of the Highly Active Polyhydroxyalkanoate Synthase of Chromobacterium sp. Strain USM2

Applied and Environmental Microbiology ◽

10.1128/aem.01997-10 ◽

2011 ◽

Vol 77 (9) ◽

pp. 2926-2933 ◽

Cited By ~ 30

Author(s):

Kesaven Bhubalan ◽

Jo-Ann Chuah ◽

Fumi Shozui ◽

Christopher J. Brigham ◽

Seiichi Taguchi ◽

...

Keyword(s):

Escherichia Coli ◽

Specific Activity ◽

Weight Percent ◽

Pha Synthase ◽

Content Type ◽

Highly Active ◽

Key Enzyme ◽

Polyhydroxyalkanoate Synthase

ABSTRACTThe synthesis of bacterial polyhydroxyalkanoates (PHA) is very much dependent on the expression and activity of a key enzyme, PHA synthase (PhaC). Many efforts are being pursued to enhance the activity and broaden the substrate specificity of PhaC. Here, we report the identification of a highly active wild-type PhaC belonging to the recently isolatedChromobacteriumsp. USM2 (PhaCCs). PhaCCsshowed the ability to utilize 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) monomers in PHA biosynthesis. Anin vitroassay of recombinant PhaCCsexpressed inEscherichia colishowed that its polymerization of 3-hydroxybutyryl-coenzyme A activity was nearly 8-fold higher (2,462 ± 80 U/g) than that of the synthase from the model strainC. necator(307 ± 24 U/g). Specific activity using a Strep2-tagged, purified PhaCCswas 238 ± 98 U/mg, almost 5-fold higher than findings of previous studies using purified PhaC fromC. necator. Efficient poly(3-hydroxybutyrate) [P(3HB)] accumulation inEscherichia coliexpressing PhaCCsof up to 76 ± 2 weight percent was observed within 24 h of cultivation. To date, this is the highest activity reported for a purified PHA synthase. PhaCCsis a naturally occurring, highly active PHA synthase with superior polymerizing ability.

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