501 research outputs found

    An investigation on polymeric blend mixed matrix membranes of polyethersulfone/polyvinyl acetate/carbon molecular sieve for CO2/Ch4 separation

    Get PDF
    Polymeric membranes have been vastly used for gas separation purposes however they have an upper-bound trade off problem which is the reason why this research work is focusing on inorganic filler added to polymer blend membranes to enhance the selectivity and permeability of the resulted membranes. Different percentages (5, 10 and 15 wt.%) of carbon molecular sieve (CMS) were added to a blend of polyethersulfone/polyvinyl acetate (PES/PVAc) (90/10) to produce polymeric blend mixed matrix membranes (PB3M) by solvent evaporation method. These membranes were characterized by field emission scanning electron microscopy (FESEM) to find out the membrane morphology and then their gas separation performance was assessed using high purity CO2 and CH4 gases. Addition of CMS to the blend of this glassy and rubbery polymer, increased the CO2/CH4 selectivity and CO2 permeability of the resulted PB3Ms. The highest selectivity which was 43.26 was achieved at 10 bar and at room temperature by adding 15% CMS to the polymer blend membrane.Keywords: Mixed Matrix membrane; polyvinyl acetate; polyethersulfone; carbon molecularsiev

    Young Adult with Canon Ball Lung Metastasis and Unknown Primary: A Case of Primary Pulmonary Myxoid Sarcoma

    Full text link
    Extra skeletal Myxoid Chondrosarcoma (EMC) is a rare soft tissue sarcoma, which primarily occurs deep in extremities, especially in the skeletal muscle or tendon. Unusual locations include tongue, retroperitoneum, spine, intracranium, testis, inguinal region, synovium, mammary gland, labium and pleura, however no case of has been described the aggressive involvement of lung with multiple canon ball metastatic atypical chondromyxoid neoplasm with unknown primary. We hereby present a 38 year old Asian male patient initially presented for cough and occasional blood stained sputum with chest pain since few days, found to have multiple canon ball lung lesions which histopathological suggestive of atypical chondromyxoidnbsp sarcoma and primary source remained to be unknown. nbs

    Isolation of klebsiella pneumoniae from Sungai Skudai and in silico analysis of putative dehalogenase protein by

    Get PDF
    Aims: The surplus use of herbicide Dalapon® contains 2,2-dichloropropionic acid (2,2-DCP) poses great danger to human and ecosystem due to its toxicity. Hence, this study focused on the isolation and characterization of a dehalogenase producing bacteria from Sungai Skudai, Johor, capable of utilizing 2,2-DCP as a carbon source and in silico analysis of its putative dehalogenase. Methodology and results: Isolation of the target bacteria was done by using 2,2-DCP-enriched culture as the sole carbon source that allows a bacterium to grow in 20 mM of 2,2-DCP at 30 °C with the corresponding doubling time of 8.89 ± 0.03 h. The isolated bacterium was then designated as Klebsiella pneumoniae strain YZ based on biochemical tests and basic morphological examination. The full genome of K. pneumoniae strain KLPN_25 (accession number: RRE04903) which obtained from NCBI database was screened for the presence of dehalogenase gene, assuming both strains YZ and KLPN_25 were the same organisms. A putative dehalogenase gene was then identified as type II dehalogenase from the genome sequence of strain KLPN_25. The protein structure of the type II dehalogenase of KLPN_25 strain was then pairwise aligned with the crystal structure of L-2-haloacid dehalogenase (L-DEX) Pseudomonas sp. strain YL as the template, revealing the existence of conserved amino acids residues, uniquely known to participate in the dehalogenation mechanism. The finding thus implies that the amino acid residues of type II dehalogenase possibly shares similar catalytic functions with the L-DEX. Conclusion, significance and impact of the study: In conclusion, this study confirmed the presence of new dehalogenase from the genus Klebsiella with potential to degrade 2,2-DCP from the river water. The structural information of type II dehalogenase provides insights for future work in designing haloacid dehalogenases

    ``Smoke Rings'' in Ferromagnets

    Full text link
    It is shown that bulk ferromagnets support propagating non-linear modes that are analogous to the vortex rings, or ``smoke rings'', of fluid dynamics. These are circular loops of {\it magnetic} vorticity which travel at constant velocity parallel to their axis of symmetry. The topological structure of the continuum theory has important consequences for the properties of these magnetic vortex rings. One finds that there exists a sequence of magnetic vortex rings that are distinguished by a topological invariant (the Hopf invariant). We present analytical and numerical results for the energies, velocities and structures of propagating magnetic vortex rings in ferromagnetic materials.Comment: 4 pages, 3 eps-figures, revtex with epsf.tex and multicol.sty. To appear in Physical Review Letters. (Postscript problem fixed.

    Daily Energy Intake from Meals and Afternoon Snacks: Findings from the Malaysian Adults Nutrition Survey(MANS)

    Get PDF
    Meal and snack patterns are associated with energy and nutrient intakes and consequently health and nutritional status. The aim of this paper is to describe the percentage of daily energy intake from meals and afternoon snack among Malaysian adults. The study included a representative sample of adults aged 18- 59 years (n=7349) from a nationwide Food Consumption Survey conducted by the Ministry of Health. Information on dietary intake was obtained using a one day 24-hour diet recall (24-HDR). Dietary data on 6886 adults were analysed using Nutritionist ProTM and statistical analysis was carried out using the SPSS 13.0. The median percentage of daily energy intake is reported only for adults consuming meals and afternoon tea and by socio-demographic characteristics as well as body mass index (BMI) status. More than 80% of Malaysian adults consumed morning meals, lunch and dinner and 54% reported having afternoon tea. The median percentage of energy intake from morning meals, lunch, dinner and afternoon tea was 29.9%, 30.5%, 32.4% and 17%, respectively. There were variations in the median percentage of energy from meals and snacks according to the socio-demographic variables and BMI status. It is important to understand the eating patterns of Malaysians as the information can assist in efforts to address obesity and diet-related chronic diseases among adults

    SPIDER: a balloon-borne CMB polarimeter for large angular scales

    Get PDF
    We describe SPIDER, a balloon-borne instrument to map the polarization of the millimeter-wave sky with degree angular resolution. Spider consists of six monochromatic refracting telescopes, each illuminating a focal plane of large-format antenna-coupled bolometer arrays. A total of 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. A cold half-wave plate at the aperture of each telescope modulates the polarization of incoming light to control systematics. Spider's first flight will be a 20-30-day Antarctic balloon campaign in December 2011. This flight will map \sim8% of the sky to achieve unprecedented sensitivity to the polarization signature of the gravitational wave background predicted by inflationary cosmology. The Spider mission will also serve as a proving ground for these detector technologies in preparation for a future satellite mission.Comment: 12 pages, 6 figures; as published in the conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010

    280 GHz Focal Plane Unit Design and Characterization for the SPIDER-2 Suborbital Polarimeter

    Get PDF
    We describe the construction and characterization of the 280 GHz bolometric focal plane units (FPUs) to be deployed on the second flight of the balloon-borne SPIDER instrument. These FPUs are vital to SPIDER's primary science goal of detecting or placing an upper limit on the amplitude of the primordial gravitational wave signature in the cosmic microwave background (CMB) by constraining the B-mode contamination in the CMB from Galactic dust emission. Each 280 GHz focal plane contains a 16 x 16 grid of corrugated silicon feedhorns coupled to an array of aluminum-manganese transition-edge sensor (TES) bolometers fabricated on 150 mm diameter substrates. In total, the three 280 GHz FPUs contain 1,530 polarization sensitive bolometers (765 spatial pixels) optimized for the low loading environment in flight and read out by time-division SQUID multiplexing. In this paper we describe the mechanical, thermal, and magnetic shielding architecture of the focal planes and present cryogenic measurements which characterize yield and the uniformity of several bolometer parameters. The assembled FPUs have high yields, with one array as high as 95% including defects from wiring and readout. We demonstrate high uniformity in device parameters, finding the median saturation power for each TES array to be ~3 pW at 300 mK with a less than 6% variation across each array at one standard deviation. These focal planes will be deployed alongside the 95 and 150 GHz telescopes in the SPIDER-2 instrument, slated to fly from McMurdo Station in Antarctica in December 2018

    Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne polarimeter SPIDER

    Full text link
    We describe 280 GHz bolometric detector arrays that instrument the balloon-borne polarimeter SPIDER. A primary science goal of SPIDER is to measure the large-scale B-mode polarization of the cosmic microwave background in search of the cosmic-inflation, gravitational-wave signature. 280 GHz channels aid this science goal by constraining the level of B-mode contamination from galactic dust emission. We present the focal plane unit design, which consists of a 16×\times16 array of conical, corrugated feedhorns coupled to a monolithic detector array fabricated on a 150 mm diameter silicon wafer. Detector arrays are capable of polarimetric sensing via waveguide probe-coupling to a multiplexed array of transition-edge-sensor (TES) bolometers. The SPIDER receiver has three focal plane units at 280 GHz, which in total contains 765 spatial pixels and 1,530 polarization sensitive bolometers. By fabrication and measurement of single feedhorns, we demonstrate 14.7^{\circ} FHWM Gaussian-shaped beams with <<1% ellipticity in a 30% fractional bandwidth centered at 280 GHz. We present electromagnetic simulations of the detection circuit, which show 94% band-averaged, single-polarization coupling efficiency, 3% reflection and 3% radiative loss. Lastly, we demonstrate a low thermal conductance bolometer, which is well-described by a simple TES model and exhibits an electrical noise equivalent power (NEP) = 2.6 ×\times 1017^{-17} W/Hz\sqrt{\mathrm{Hz}}, consistent with the phonon noise prediction.Comment: Proceedings of SPIE Astronomical Telescopes + Instrumentation 201

    The balloon-borne large-aperture submillimeter telescope for polarimetry: BLAST-Pol

    Full text link
    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLAST-Pol) is a suborbital mapping experiment designed to study the role played by magnetic fields in the star formation process. BLAST-Pol is the reconstructed BLAST telescope, with the addition of linear polarization capability. Using a 1.8 m Cassegrain telescope, BLAST-Pol images the sky onto a focal plane that consists of 280 bolometric detectors in three arrays, observing simultaneously at 250, 350, and 500 um. The diffraction-limited optical system provides a resolution of 30'' at 250 um. The polarimeter consists of photolithographic polarizing grids mounted in front of each bolometer/detector array. A rotating 4 K achromatic half-wave plate provides additional polarization modulation. With its unprecedented mapping speed and resolution, BLAST-Pol will produce three-color polarization maps for a large number of molecular clouds. The instrument provides a much needed bridge in spatial coverage between larger-scale, coarse resolution surveys and narrow field of view, and high resolution observations of substructure within molecular cloud cores. The first science flight will be from McMurdo Station, Antarctica in December 2010.Comment: 14 pages, 9 figures Submitted to SPIE Astronomical Telescopes and Instrumentation Conference 201
    corecore