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Sample records for filled high-density polyethylene

  1. Determination of Thermal Properties and Morphology of Eucalyptus Wood Residue Filled High Density Polyethylene Composites

    PubMed Central

    Mengeloglu, Fatih; Kabakci, Ayse

    2008-01-01

    Thermal behaviors of eucalyptus wood residue (EWR) filled recycled high density polyethylene (HDPE) composites have been measured applying the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Morphology of the materials was also studied using scanning electron microscope (SEM). Addition of the EWR into the recycled HDPE matrix reduced the starting of degradation temperature. EWR filled recycled HDPE had two main decomposition peaks, one for EWR around 350 °C and one for recycled HDPE around 460 °C. Addition of EWR did not affect the melting temperature of the recycled HDPE. Morphological study showed that addition of coupling agent improved the compatibility between wood residue and recycled HDPE. PMID:19325736

  2. Photothermal Characterization of Nanocomposites Based on High Density Polyethylene (HDPE) Filled with Expanded Graphite

    NASA Astrophysics Data System (ADS)

    Chirtoc, M.; Horny, N.; Henry, J.-F.; Turgut, A.; Kökey, I.; Tavman, I.; Omastová, M.

    2012-11-01

    The effective thermophysical and optical properties of high density polyethylene (HDPE) filled with 50 μm and 5 μm particle sizes of expanded graphite (EG50, EG5) are characterized. The methods used were front- and back-detection modulated photothermal radiometry (FD-, BD-PTR) and BD-flash IR thermography. Results were interpreted according to one-dimensional heat diffusion models. The absolute thermal diffusivity was determined at low frequency from FD- and BD-PTR spectra, while the volumetric heat capacity, the thermal effusivity, and the optical absorption coefficient were determined from broad-band FD-PTR spectra. The directly obtained diffusivity values compare well with those calculated from the heat capacity and thermal effusivity, and with BD-flash results. The errors caused by the finite absorption coefficient of diluted samples are also evaluated and corrected for. A particle-size effect with the opposite influence on thermal and optical properties has been observed. Heat transport parameters of HDPE/EG composites are significantly enhanced (factor of 3 to 4 in thermal diffusivity) at low particle charge before reaching saturation above a 0.10 particle volume fraction. These features are explained in the framework of effective medium models by strongly non-spherical EG particles.

  3. Kinetics of Moisture Absorption for Alkali Extracted Steam-Exploded Fiber Filled High-Density Polyethylene Composites

    SciTech Connect

    Taib, R. M.; Ramarad, S.; Ishak, Z. A. M.; Rozman, H. D.

    2010-03-11

    Acacia mangium wood fiber derived from steam-explosion and fiber fractionation treatment was used as fillers for high-density polyethylene (HDPE). The alkali extracted steam-exploded fibers (AEF) obtained were acetylated to produce acetylated fibers (AAEF) having three different weight percent gain (WPG). Composites of AEF or AAEF and HDPE were prepared via 2-roll mill, compression molded and cut into dumbbell specimens. All samples were immersed in water at room temperature for 30 days. The process of absorption of water by all composites followed the kinetics and mechanisms described by the Fick's theory. Diffusion coefficient (D) values increased with filler loading but decreased with increasing WPG of the AAEF fiber. Further decrease was observed when maleated polyethylene (MAPE) was added to the composite system. This was due to improved fiber-matrix adhesion that restricts movement of water molecules from further penetrate inside the composite structures.

  4. Kinetics of Moisture Absorption for Alkali Extracted Steam-Exploded Fiber Filled High-Density Polyethylene Composites

    NASA Astrophysics Data System (ADS)

    Taib, R. M.; Ramarad, S.; Ishak, Z. A. M.; Rozman, H. D.

    2010-03-01

    Acacia mangium wood fiber derived from steam-explosion and fiber fractionation treatment was used as fillers for high-density polyethylene (HDPE). The alkali extracted steam-exploded fibers (AEF) obtained were acetylated to produce acetylated fibers (AAEF) having three different weight percent gain (WPG). Composites of AEF or AAEF and HDPE were prepared via 2-roll mill, compression molded and cut into dumbbell specimens. All samples were immersed in water at room temperature for 30 days. The process of absorption of water by all composites followed the kinetics and mechanisms described by the Fick's theory. Diffusion coefficient (D) values increased with filler loading but decreased with increasing WPG of the AAEF fiber. Further decrease was observed when maleated polyethylene (MAPE) was added to the composite system. This was due to improved fiber-matrix adhesion that restricts movement of water molecules from further penetrate inside the composite structures.

  5. Vacuum Outgassing of High Density Polyethylene

    SciTech Connect

    Dinh, L N; Sze, J; Schildbach, M A; Chinn, S C; Maxwell, R S; Raboin, P; McLean II, W

    2008-08-11

    A combination of thermogravimetric analysis (TGA) and temperature programmed decomposition (TPD) was employed to identify the outgassing species, the total amount of outgassing, and the outgassing kinetics of high density polyethylene (HDPE) in a vacuum environment. The isoconversional kinetic analysis was then used to analyze the outgassing kinetics and to predict the long-term outgassing of HDPE in vacuum applications at ambient temperature. H{sub 2}O and C{sub n}H{sub x} with n as high as 9 and x centering around 2n are the major outgassing species from solid HDPE, but the quantities evolved can be significantly reduced by vacuum baking at 368 K for a few hours prior to device assembly.

  6. THz-Spectroscopy on High Density Polyethylene with Different Crystallinity

    NASA Astrophysics Data System (ADS)

    Sommer, Stefan; Raidt, Thomas; Fischer, Bernd M.; Katzenberg, Frank; Tiller, Jörg C.; Koch, Martin

    2016-02-01

    The different crystallinity states of high density polyethylene (PE-HD) are investigated using THz time-domain spectroscopy by exploiting the complex permittivity at a frequency range from 0.5 up to 3.5 THz. We found that samples with different crystallinity can be distinguished by comparing the material specific refractive index ( n) or rather the linked complex part of the permittivity (∈ ' '). Correlating the calorimetrically determined degrees of crystallinity with the absolute values of the refractive index and the specific absorption peak at 2.18 THz, respectively, suggests in both cases a linear correlation.

  7. Catalytic degradation of high density polyethylene using zeolites.

    PubMed

    Zaggout, F R; al Mughari, A R; Garforth, A

    2001-01-01

    Plastic wastes, which cause a serious environmental problem in urban areas, can serve as sources of energy. Catalytic treatment of High Density Polyethylene (HDPE) has shown that the degradation of HDPE resulted in the production of a stream of gaseous hydrocarbons varied in the range C1-C8. The degradation was carried out using diluted forms of zeolites ZSM-5, USY and Mordenite (MORD) using a fluidized bed reactor (FBR). Effect of coke formation on the activity of the catalysts was screened by thermogravimetric (TGA). ZSM-5 showed a significant resistance to deactivation because of the nature of its small pore size compared with USY and MORD. PMID:11382018

  8. Scoping study. High density polyethylene (HDPE) in salstone service

    SciTech Connect

    Phifer, Mark A.

    2005-02-18

    An evaluation of the use of high density polyethylene (HDPE) geomembranes in Saltstone service has been conducted due to the potential benefits that could be derived from such usage. HDPE is one of the simplest hydrocarbon polymers and one of the most common polymers utilized in the production of geomembranes, which means that its costs are relatively low. Additionally, HDPE geomembranes have an extremely low permeability and an extremely low water vapor diffusional flux, which means that it is a good barrier to contaminant transport. The primary consideration in association with HDPE geomembranes in Saltstone service is the potential impact of Saltstone on the degradation of the HDPE geomembranes. Therefore, the evaluation documented herein has primarily focused upon the potential HDPE degradation in Saltstone service.

  9. Analyzing and improving viscoelastic properties of high density polyethylene

    NASA Astrophysics Data System (ADS)

    Ahmed, Reaj Uddin

    2011-12-01

    High Density Polyethylene (HDPE) is closely packed, less branched polyethylene having higher mechanical properties, chemical resistance, and heat resistance than Low Density Polyentylene (LDPE). Better properties and cost effectiveness make it an important raw material over LDPE in packaging industries. Stacked containers made of HDPE experience static loading and deformation strain during their storage period in a warehouse. As HDPE is a viscoelastic material, dimensional stability of stacked HDPE containers depends on time dependent properties such as creep and stress relaxation. Now, light weighting is a driving force in packaging industries, which results in lower production costs but performance of the product becomes a challenge. Proper understanding of the viscoelastic properties of HDPE, with relevant FE simulation can facilitate improved designs. This research involves understanding and improving viscoelastic properties, creep behavior, and stress relaxation of HDPE. Different approaches were carried out to meet the objectives. Organic filler CaCO3 was added to HDPE at increasing weight fractions and corresponding property changes were investigated. Annealing heat treatments were also carried out for potential property improvements. The effect of ageing was also investigated on both annealed and non annealed HDPE. The related performance of different water bottles against squeeze pressure was also characterized. Both approaches, incorporation of CaCO3 and annealing, showed improvements in the properties of HDPE over neat HDPE. This research aids finding the optimum solution for improving viscoelastic properties, stress relaxation, and creep behavior of HDPE in manufacturing.

  10. The electrical properties of schungite-containing compositions based on polypropylene and high-density polyethylene

    NASA Astrophysics Data System (ADS)

    Rozhkov, S. S.; Kedrina, N. F.; Timofeeva, V. A.; Chmutin, I. A.; Ryvkina, N. G.; Solov'eva, A. B.

    2007-11-01

    Variations in the dc and ac conductivities of schungite-containing compositions based on polypropylene-high-density polyethylene (PP-PE) blends were studied depending on the composition of the polymeric blend, the volume concentration of the filler, and the order of the introduction of the composition components during the preparation of compositions. It was shown that the conductivities of the compositions could depend on the order of the introduction of the components. The structure of initial and schungite-containing PP-PE blends of different compositions was studied by atomic-force microscopy. It was shown that the structure of the compositions depended on the composition of the initial PP-PE blends and the order of the introduction of the components into schungite-filled PP-PE compositions.

  11. Measurements and predictions of outgassing from high density polyethylene (HDPE), PBX9502, and certain silicones by the isoconversional analysis

    SciTech Connect

    Dinh, L N; Glascoe, E A; Schildbach, M A; Chinn, S C; Maxwell, R S; McLean II, W

    2009-07-06

    The techniques of mass spectrometry and temperature programmed decomposition were used to measure outgassing kinetics from high density polyethylene, insensitive high explosive PBX 9502, and silica-filled polysiloxane TR55 and S5370. The isoconversional thermal analysis method was then employed to extract outgassing kinetics and to make kinetic predictions for long term outgassing at lower temperatures. The accuracy, advantages and disadvantages of the isoconversional analysis in terms of kinetic prediction for these materials and some others will be discussed.

  12. Properties of high density polyethylene – Paulownia wood flour composites via injection molding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Paulownia wood (PW) flour is evaluated as a bio-based fiber reinforcement. Composites of high density polyethylene (HDPE), 25% by weight of PW, and either 0% or 5% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding followed by injection molding. Molded test composite...

  13. Mechanical and thermal properties of high density polyethylene – dried distillers grains with solubles composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dried Distillers Grain with Solubles (DDGS) is evaluated as a bio-based fiber reinforcement. Injection molded composites of high density polyethylene (HDPE), 25% by weight of DDGS, and either 5% of 0% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding and injection mo...

  14. An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends.

    PubMed

    Ahmed, Khalil

    2015-11-01

    Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (M L) and maximum torque (M H) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties. PMID:26644917

  15. An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends

    PubMed Central

    Ahmed, Khalil

    2014-01-01

    Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (ML) and maximum torque (MH) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties. PMID:26644917

  16. The application and progress of high-density porous polyethylene in the repair of orbital wall defect.

    PubMed

    Qian, Zhuyun; Fan, Xianqun

    2014-07-01

    High-density porous polyethylene is a type of polymeric biomaterial. When used to efficiently fill the extensive orbital volume and correct enophthalmos caused by orbital wall defect, it has a significant advantage of biocompatibility, which results in a low rate of postoperative exposure and infection. The major disadvantage of this material is its radiolucency. However, with the development of imaging techniques, it is now possible to use multidetector computed tomography to directly contour the implant and describe its position. The use of tissue engineering involving high-density porous polyethylene will further improve its biocompatibility. At the same time, composite materials will play an important role in the repair of orbital wall defect. PMID:24911609

  17. Mechanical properties of high density polyethylene--pennycress press cake composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennycress press cake (PPC) is evaluated as a bio-based fiber reinforcement. PPC is a by-product of crop seed oil extraction. Composites with a high density polyethylene (HDPE) matrix are created by twin screw compounding of 25% by weight of PPC and either 0% or 5% by weight of maleated polyethyle...

  18. Catalytic and thermal depolymerization of low value post-consumer high density polyethylene plastic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The feasibility of catalytic and non-catalytic pyrolytic conversion of low value post-consumer high density polyethylene (HDPE) plastic into crude oil and subsequent distillation was explored. Translation of optimized conditions for catalytic and non-catalytic pyrolysis from TGA to a bench-scale sys...

  19. 77 FR 13387 - Pipeline Safety: Notice to Operators of Driscopipe® 8000 High Density Polyethylene Pipe of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-06

    ... 8000 High Density Polyethylene Pipe of the Potential for Material Degradation AGENCY: Pipeline and.... SUMMARY: PHMSA is issuing this advisory bulletin to alert operators using Driscopipe 8000 High Density... authorities. II. Advisory Bulletin (ADB-2012-03) To: Operators using Driscopipe 8000 High Density...

  20. The yield and post-yield behavior of high-density polyethylene

    NASA Technical Reports Server (NTRS)

    Semeliss, M. A.; Wong, R.; Tuttle, M. E.

    1990-01-01

    An experimental and analytical evaluation was made of the yield and post-yield behavior of high-density polyethylene, a semi-crystalline thermoplastic. Polyethylene was selected for study because it is very inexpensive and readily available in the form of thin-walled tubes. Thin-walled tubular specimens were subjected to axial loads and internal pressures, such that the specimens were subjected to a known biaxial loading. A constant octahederal shear stress rate was imposed during all tests. The measured yield and post-yield behavior was compared with predictions based on both isotropic and anisotropic models. Of particular interest was whether inelastic behavior was sensitive to the hydrostatic stress level. The major achievements and conclusions reached are discussed.

  1. Wood plastic composites based on microfibrillar blends of high density polyethylene/poly(ethylene terephthalate).

    PubMed

    Lei, Yong; Wu, Qinglin

    2010-05-01

    High-melting-temperature poly(ethylene terephthalate) (PET) was successfully introduced into wood plastic composites through a two-step reactive extrusion technology. Wood flour was added into pre-prepared PET/high density polyethylene (HDPE) microfibrillar blends (MFBs) in the second extrusion at the temperature for processing HDPE. Addition of 25% in situ formed PET microfibers obviously increased the mechanical properties of HDPE, and more significant enhancement by the in situ formed recycled PET microfibers was observed for the recycled HDPE. Adding 2% E-GMA improved the compatibility between matrix and microfibers in MFBs, resulting further enhanced mechanical properties. The subsequent addition of 40% wood flour did not influence the size and morphology of PET microfibers, and improved the comprehensive mechanical properties of MFBs. The wood flour increased the crystallinity level of HDPE in the compatibilized MFB in which PET phase did not crystallize. The storage modulus of MFB was greatly improved by wood flour. PMID:20100654

  2. Statistical modeling of crack growth and reliability assessment of high-density polyethylene

    SciTech Connect

    Qureshi, F.S.; Sheikh, A.K.; Khan, Z.; Ahmad, M.

    1999-06-01

    In this work, a statistical evaluation of the crack-growth process in high-density polyethylene (HDPE) was carried out. The specimens were compression molded from virgin, molding-grade HDPE. Edge-notched specimens for replicate fatigue testing were prepared from compression-molded sheets. Fatigue test results were then analyzed, and it is shown that if the crack-growth process can be characterized as a random process following a power-law-type behavior, then the time to reach a critical crack length will be distributed according to an inverted lognormal model.

  3. High-density polyethylene pipe: A new material for pass-by passive integrated transponder antennas

    USGS Publications Warehouse

    Kazyak, David C.; Zydlewski, Joseph

    2012-01-01

    Pass-by passive integrated transponder (PIT) antennas are widely used to study the movements of fish in streams. At many sites, stream conditions make it difficult to maintain antennas and obtain a continuous record of movement. We constructed pass-by PIT antennas by using high-density polyethylene (HDPE) and found them to be robust to high flows and winter ice flows. Costs for HDPE antennas were similar to those of traditional polyvinyl chloride (PVC) antennas, although construction was somewhat more complicated. At sites where PVC antennas are frequently damaged, HDPE is a durable and economical alternative for PIT antenna construction.

  4. Solving a product safety problem using a recycled high density polyethylene container

    NASA Technical Reports Server (NTRS)

    Liu, Ping; Waskom, T. L.

    1993-01-01

    The objectives are to introduce basic problem-solving techniques for product safety including problem identification, definition, solution criteria, test process and design, and data analysis. The students are given a recycled milk jug made of high density polyethylene (HDPE) by blow molding. The objectives are to design and perform proper material test(s) so they can evaluate the product safety if the milk jug is used in a certain way which is specified in the description of the procedure for this investigation.

  5. Large area neutron detector based on Li6 ionization chamber with integrated body-moderator of high density polyethylene

    SciTech Connect

    Ianakiev, Kiril D.; Swinhoe, Martyn T.; Chung, Kiwhan; Makela, Mark F.

    2009-06-30

    A detector was developed and funded by DHS to be a lower cost alternative to 3He detectors. A 6Li foil-lined ionization chamber was prepared with fill gas at one atmosphere and pulse mode operation. The high-density polyethylene (HOPE) body serves also as a neutron moderator. All electrodes, including high voltage bias supply, are hermetically sealed within the plastic slabs.

  6. Effect of ultraviolet radiation in the photo-oxidation of High Density Polyethylene and Biodegradable Polyethylene films

    NASA Astrophysics Data System (ADS)

    Martínez-Romo, A.; González Mota, R.; Bernal, J. J. Soto; Frausto Reyes, C.; Rosales Candelas, I.

    2015-01-01

    One of the most widely used plastics in the world is the High density polyethylene (HDPE), it is a stable material due to its carbon-carbon bonds, causing their slow degradation; which is why we are looking for alternative ways to accelerate the degradation process of this polymer. An alternative is the addition of oxidized groups in its molecular structure, which results in the development of polymers susceptible to biodegradation (PE-BIO). In this paper, HDPE and PE-BIO films were exposed to UV-B radiation (320-280 nm) at different exposure times, 0-60 days. The effects of UV radiation in samples of HDPE and PE-BIO were characterized using infrared spectroscopy with attenuated total reflectance (ATR). The results show that the exposed materials undergo changes in their molecular structure, due to the infrared bands formed which corresponds to the photo-oxidation of HDPE and PE films when submitted to UV-B radiation.

  7. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    NASA Astrophysics Data System (ADS)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

    2015-04-01

    A recent low gas-fill density (0.6 mg/cc 4He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  8. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    SciTech Connect

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

    2015-04-15

    A recent low gas-fill density (0.6 mg/cc {sup 4}He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc {sup 4}He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  9. Reaction between Steel-Making Slag and Carbonaceous Materials While Mixing with High Density Polyethylene

    NASA Astrophysics Data System (ADS)

    Hong, Lan; Sahajwalla, Veena

    2016-01-01

    Since the beginning of the extensive applications in numerous high temperature processes such as iron- and steel-making, coke-making etc. partly in the place of coke, the investigation into the reaction mechanism of waste plastics has become increasingly necessary. In this paper a fundamental study on the behavior of a typical component of waste plastics, high density polyethylene (HDPE), in a mixture with coke at a 1:1 ratio in mass base was conducted during the reaction with iron oxide in steel-making slag at 1823 K and was compared with coke and graphite. The reaction mechanism of carbonaceous materials was analyzed based on the contents of CO and CO2 in the off-gas monitored by an infrared (IR) gas analyzer. It is clear from the results that the reaction of HDPE and coke mixture with steel-making slag approached equilibrium of the Boudouard reaction more quickly and closely than coke or graphite.

  10. Strain-rate/temperature behavior of high density polyethylene in compression

    NASA Technical Reports Server (NTRS)

    Clements, L. L.; Sherby, O. D.

    1978-01-01

    The compressive strain rate/temperature behavior of highly linear, high density polyethylene was analyzed in terms of the predictive relations developed for metals and other crystalline materials. For strains of 5 percent and above, the relationship between applied strain rate, dotted epsilon, and resulting flow stress, sigma, was found to be: dotted epsilon exp times (Q sub f/RT) = k'(sigma/sigma sub c) to the nth power; the left-hand side is the activation-energy-compensated strain rate, where Q sub f is activation energy for flow, R is gas constant, and T is temperature; k is a constant, n is temperature-independent stress exponent, and sigma/sigma sub c is structure-compensated stress. A master curve resulted from a logarithmic plot of activation-energy-compensated strain rate versus structure-compensated stress.

  11. A multivariate analysis of the effects of multiple extrusion cycles on high density polyethylene bottle resin

    SciTech Connect

    Zahavich, A.

    1995-10-01

    The recycling of post consumer (PCR) high density polyethylene (HDPE) blow molding resins has increased dramatically over the past 5 years. The focus of research for this product has been on specific performance and processing properties such as tensile or melt strength. Little work has been done on studying the entire range of properties as a whole, particularly in the area of multiple extrusions. This paper describes a designed experiment study where multivariate statistical techniques were used to compare 2 HDPE and 2 HDPE PCR materials, in terms of changes in a number of properties with exposure to multiple extrusions. Virgin homopolymer and copolymer resins and PCR, mixed color bottle and natural, were passed through 4 extrusion cycles. Viscosity, swell, melt strength, crystallinity, polydispersity and ESCR properties were studied using principal component analysis.

  12. Interfacial thermal resistance between high-density polyethylene (HDPE) and sapphire

    NASA Astrophysics Data System (ADS)

    Zheng, Kun; Zhu, Jie; Ma, Yong-Mei; Tang, Da-Wei; Wang, Fo-Song

    2014-10-01

    To improve the thermal conductivity of polymeric composites, the numerous interfacial thermal resistance (ITR) inside is usually considered as a bottle neck, but the direct measurement of the ITR is hardly reported. In this paper, a sandwich structure which consists of transducer/high density polyethylene (HDPE)/sapphire is prepared to study the interface characteristics. Then, the ITRs between HDPE and sapphire of two samples with different HDPE thickness values are measured by time-domain thermoreflectance (TDTR) method and the results are ~ 2 × 10-7 m2·K·W-1. Furthermore, a model is used to evaluate the importance of ITR for the thermal conductivity of composites. The model's analysis indicates that reducing the ITR is an effective way of improving the thermal conductivity of composites. These results will provide valuable guidance for the design and manufacture of polymer-based thermally conductive materials.

  13. Load effect on an SMS fiber structure embedded in a high-density polyethylene

    NASA Astrophysics Data System (ADS)

    Puspita, Ika; Rahmah, Fitri; Hatta, Agus M.; Koentjoro, Sekartedjo

    2015-01-01

    In this paper, a load effect on a singlemode-multimode-singlemode (SMS) fiber structure embedded in a high-density polyethylene (HDPE) was investigated numerically and experimentally. It was modelled that the applied load induces a longitudinal strain on the HDPE and accordingly affects the SMS fiber structure's parameters. It was calculated the output power of the SMS fiber structure using a graded index multimode fiber (MMF) due to the applied strain from 0 to 4000 N. The experimental result shows that for the MMF length of 105 mm, the output power has monotonically increasing for an applied load range from 1700 to 4000 N with a sensitivity of 1.18 x 10-3 dBm/N. This configuration of SMS fiber structure embedded in the HDPE is potential for a load sensor.

  14. Gasification of biomass/high density polyethylene mixtures in a downdraft gasifier.

    PubMed

    García-Bacaicoa, P; Mastral, J F; Ceamanos, J; Berrueco, C; Serrano, S

    2008-09-01

    In this work, an experimental study of the thermal decomposition of mixtures of wood particles and high density polyethylene in different atmospheres has been carried out in a downdraft gasifier with a nominal processing capacity of 50 kg/h. The main objective was to study the feasibility of the operation of the gasification plant using mixtures and to investigate the characteristics of the gas obtained. In order to do so, experiments with biomass only and with mixtures with up to 15% HDPE have been carried out. The main components of the gas generated are N(2) (50%), H(2) (14%), CO (9-22%) and CO(2) (7-17%) and its relatively high calorific value was adequate for using it in an internal combustion engine generator consisting of a modified diesel engine coupled with a 25 kV A alternator. PMID:18083026

  15. Product distribution modelling in the thermal pyrolysis of high density polyethylene.

    PubMed

    Elordi, G; Lopez, G; Olazar, M; Aguado, R; Bilbao, J

    2007-06-18

    The thermal fast pyrolysis of high density polyethylene (HDPE) has been carried out in a conical spouted bed reactor in the 450-715 degrees C range, and individual products have been monitored with the aim of obtaining kinetic data for the design and simulation of this process at large scale. Kinetic schemes have been proposed in order to explain both the results obtained in the laboratory plant and those obtained in the literature by other authors operating at laboratory and larger scale. Discrimination has been carried out based on the contribution of the variance of model parameters (stepwise regression) to the total variance explained by the model. The models based on that of Westerhout et al. [R.W.J. Westerhout, J. Waanders, W.P.M. Van Swaaij, Recycling of polyethene and polypropene in a novel bench-scale rotating cone reactor by high-temperature pyrolysis. Ind. Eng. Chem. Res. 37 (6) (1998) 2293-2300] do not adequately predict the experimental results, especially those corresponding to aromatics and char, which is probably due to the very short residence times attained in the conical spouted bed and, consequently, to the lower yields of aromatics and char. The model of best fit is the one where polyethylene degrades to give gas, liquid (oil) and wax fractions. Furthermore, the latter undergoes secondary reactions to give liquid and aromatics, which in turn produce more char. PMID:17337118

  16. In-situ Production of High Density Polyethylene and Other Useful Materials on Mars

    NASA Technical Reports Server (NTRS)

    Flynn, Michael

    2005-01-01

    This paper describes a revolutionary materials structure and power storage concept based on the in-situ production of abiotic carbon 4 compounds. One of the largest single mass penalties required to support the human exploration of Mars is the surface habitat. This proposal will use physical chemical technologies to produce high density polyethylene (HDPE) inflatable structures and construction materials from Mars atmospheric CO2. The formation of polyethylene from Mars CO2 is based on the use of the Sabatier and modified Fischer Tropsch reactions. The proposed system will fully integrate with existing in-situ propellant production concepts. The technology will also be capable of supplementing human caloric requirements, providing solid and liquid fuels for energy storage, and providing significant reduction in mission risk. The NASA Mars Reference Mission Definition Team estimated that a conventional Mars surface habitat structure would weigh 10 tonnes. It is estimated that this technology could reduce this mass by 80%. This reduction in mass will significantly contribute to the reduction in total mission cost need to make a Mars mission a reality. In addition the potential reduction of risk provided by the ability to produce C4 and potentially higher carbon based materials in-situ on Mars is significant. Food, fuel, and shelter are only three of many requirements that would be impacted by this research.

  17. Friction and wear of hydroxyapatite reinforced high density polyethylene against the stainless steel counterface.

    PubMed

    Wang, M; Chandrasekaran, M; Bonfield, W

    2002-06-01

    Hydroxyapatite (HA) reinforced high density polyethylene (HDPE) was invented as a biomaterial for skeletal applications. In this investigation, tribological properties (e.g. wear rate and coefficient of friction) of unfilled HDPE and HA/HDPE composites were evaluated against the duplex stainless steel in dry and lubricated conditions, with distilled water or aqueous solutions of proteins (egg albumen or glucose) being lubricants. Wear tests were conducted in a custom-built test rig for HDPE and HA/HDPE containing up to 40 vol % of HA. It was found that HA/HDPE composites had lower coefficients of friction than unfilled HDPE under certain conditions. HA/HDPE also exhibited less severe fatigue failure marks than HDPE. The degradation and fatigue failure of HDPE due to the presence of proteins were severe for low speed wear testing (100 rpm) as compared to high speed wear testing (200 rpm). This was due possibly to the high shear rate at the contact which could remove any degraded film instantaneously at high sliding speed, while with a low sliding speed the build-up of a degraded layer of protein could occur. The degraded protein layer would stay at the contact for a longer time and mechanical activation would induce adverse reactions, weakening the surface layer of HDPE. Both egg albumen and glucose were found to be corrosive to steel and adversely reactive for HDPE and HA/HDPE composites. The wear modes observed were similar to that of ultra-high molecular weight polyethylene. Specimens tested with egg albumen also displayed higher wear rates, which was again attributed to corrosion accelerated wear. PMID:15348592

  18. Preparation and properties of banana fiber-reinforced composites based on high density polyethylene (HDPE)/Nylon-6 blends.

    PubMed

    Liu, H; Wu, Q; Zhang, Q

    2009-12-01

    Banana fiber (BaF)-filled composites based on high density polyethylene (HDPE)/Nylon-6 blends were prepared via a two-step extrusion method. Maleic anhydride grafted styrene/ethylene-butylene/styrene triblock polymer (SEBS-g-MA) and maleic anhydride grafted polyethylene (PE-g-MA) were used to enhance impact performance and interfacial bonding between BaF and the resins. Mechanical, crystallization/melting, thermal stability, water absorption, and morphological properties of the composites were investigated. In the presence of SEBS-g-MA, better strengths and moduli were found for HDPE/Nylon-6 based composites compared with corresponding HDPE based composites. At a fixed weight ratio of PE-g-MA to BaF, an increase of BaF loading up to 48.2 wt.% led to a continuous improvement in moduli and flexural strength of final composites, while impact toughness was lowered gradually. Predicted tensile modulus by the Hones-Paul model for three-dimensional random fiber orientation agreed well with experimental data at the BaF loading of 29.3 wt.%. However, the randomly-oriented fiber models underestimated experimental data at higher fiber levels. It was found that the presence of SEBS-g-MA had a positive influence on reinforcing effect of the Nylon-6 component in the composites. Thermal analysis results showed that fractionated crystallization of the Nylon-6 component in the composites was induced by the addition of both SEBS-g-MA and PE-g-MA. Thermal stability of both composite systems differed slightly, except an additional decomposition peak related to the minor Nylon-6 for the composites from the HDPE/Nylon-6 blends. In the presence of SEBS-g-MA, the addition of Nylon-6 and increased BaF loading level led to an increase in the water absorption value of the composites. PMID:19574041

  19. Current Activities Assessing Butt Fusion Joint Integrity in High Density Polyethylene Piping

    SciTech Connect

    Crawford, Susan L.; Cinson, Anthony D.; Doctor, Steven R.; Denslow, Kayte M.

    2012-09-01

    The Pacific Northwest National Laboratory (PNNL) in Richland, Washington, conducted initial studies to evaluate the effectiveness of nondestructive examinations (NDE) coupled with mechanical testing for assessing butt fusion joint integrity in high density polyethylene (HDPE) pipe. The work provided insightful information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of volumetric inspection techniques for detecting lack of fusion (LOF) conditions in the fusion joints. HDPE has been installed on a limited basis in American Society of Mechanical Engineers (ASME) Class 3, buried piping systems at several operating U.S. nuclear power plants and has been proposed for use in new construction. A comparison was made between the results from ultrasonic and microwave nondestructive examinations and the results from mechanical destructive evaluations, specifically the high-speed tensile test and the side-bend test, for determining joint integrity. The data comparison revealed that none of the NDE techniques detected all of the lack-of-fusion conditions that were revealed by the destructive tests. Follow-on work has recently been initiated at PNNL to accurately characterize the NDE responses from machined flaws of varying size and location in PE 4710 materials as well as the LOF condition. This effort is directed at quantifying the ability of volumetric NDE techniques to detect flaws in relation to the critical flaw size associated with joint integrity. A status of these latest investigations is presented.

  20. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    PubMed

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes. PMID:26322761

  1. Catalytic degradation of high-density polyethylene over different zeolitic structures

    SciTech Connect

    Manos, G.; Garforth, A.; Dwyer, J.

    2000-05-01

    The catalytic degradation of high-density polyethylene to hydrocarbons was studied over different zeolites. The product range was typically between C{sub 3} and C{sub 15} hydrocarbons. Distinctive patterns of product distribution were found with different zeolitic structures. Over large-pore ultrastable Y, Y, and {beta} zeolites, alkanes were the main products with less alkenes and aromatics and only very small amounts of cycloalkanes and cycloalkenes. Medium-pore mordenite and ZSM-5 gave significantly more olefins. In the medium-pore zeolites secondary bimolecular reactions were sterically hindered, resulting in higher amounts of alkenes as primary products. The hydrocarbons formed with medium-pore zeolites were lighter than those formed with large-pore zeolites. The following order was found regarding the carbon number distribution: (lighter products) ZSM-5 < mordenite < {beta} < Y < US-Y (heavier products). A similar order was found regarding the bond saturation: (more alkenes) ZSM-5 < mordenite < {beta} < Y < US-Y (more alkanes). Dependent upon the chosen zeolite, a variety of products was obtained with high values as fuel, confirming catalytic degradation of polymers as a promising method of waste plastic recycling.

  2. The use of high-density porous polyethylene as a custom-made nasal spreader graft.

    PubMed

    Gürlek, Ali; Celik, Mehmet; Fariz, Alpay; Ersöz-Oztürk, Ayşe; Eren, Ahmet T; Tenekeci, Göktekin

    2006-01-01

    The concept and technique of using high-density porous polyethylene (HDPP), a nonresorbable synthetic material, for nasal spreader grafts, are presented. This material is thought to be particularly useful in revision (secondary or tertiary) rhinoplasty, in which internal valve collapse frequently is confronted and septal cartilage often is unavailable because it has been harvested for spreader or other grafts. Sold as a thin plain sheet (0.85 x 38 x 50 mm) that can be cut to an appropriate size for spreader grafts, HDPP is a ready-to-use material commercially available on the market. Because HDPP permits ingrowths of fibrous tissue inside and around, it is a nonabsorbable material that stabilizes the upper lateral cartilages in their new position and maintains the appropriate internal valve angle. The authors used this material for 15 patients undergoing secondary (n = 12) and tertiary (n = 3) rhinoplasty because of valvular collapse. During the mean follow-up period of 16 months (range, 8-30 months), neither complication nor recurrence of airway obstruction occurred. PMID:16411156

  3. Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography.

    PubMed

    Prabhu, K N; Brüll, R; Macko, T; Remerie, K; Tacx, J; Garg, P; Ginzburg, A

    2015-11-01

    High-temperature two-dimensional liquid chromatography (HT 2D-LC) using HT-HPLC as first dimension and HT-SEC as second dimension holds enormous potential to investigate the distribution according to molar mass and chemical composition of bimodal high density polyethylene (BiHDPE), as it avoids drawbacks of crystallization-based techniques. In this study, we have stepwise optimized the chromatographic parameters of 1D, comprising gradient slope and temperature, using model homo- and copolymers of ethylene with the aim to minimize the impact of molar mass on the compositional separation. Then the HT-HPLC was hyphenated to HT-SEC and optimum conditions for the volume of the sample transfer loop were probed with regard to the resolution of BiHDPE into the individual constituents HDPE and LLDPE. A particular important aspect was the use of infrared (IR) detection, and the demands it puts on the chromatographic aspects: We have shown that IR detection can be successfully applied in HT 2D-LC of BiHDPE, which is broadly distributed with regard to short chain branching and molar mass, only when the separation in 2D is optimized with regard to chromatographic resolution. As final result a bimodality is evident in the contour and the 3D surface plots as well as in both HPLC and SEC projections generated from HT 2D-LC. PMID:26435312

  4. Dielectric, thermal and mechanical properties of zirconium silicate reinforced high density polyethylene composites for antenna applications.

    PubMed

    Varghese, Jobin; Nair, Dinesh Raghavan; Mohanan, Pezholil; Sebastian, Mailadil Thomas

    2015-06-14

    A low cost and low dielectric loss zirconium silicate (ZrSiO4) reinforced HDPE (high-density polyethylene) composite has been developed for antenna applications. The 0-3 type composite is prepared by dispersing ZrSiO4 fillers for various volume fractions (0.1 to 0.5) in the HDPE matrix by the melt mixing process. The composite shows good microwave dielectric properties with a relative permittivity of 5.6 and a dielectric loss of 0.003 at 5 GHz at the maximum filler loading of 0.5 volume fraction. The composite exhibits low water absorption, excellent thermal and mechanical properties. It shows a water absorption of 0.03 wt%, a coefficient of thermal expansion of 70 ppm per °C and a room temperature thermal conductivity of 2.4 W mK(-1). The composite shows a tensile strength of 22 MPa and a microhardness of 13.9 kg mm(-2) for the filler loading of 0.5 volume fraction. The HDPE-ZrSiO4 composites show good dielectric, thermal and mechanical properties suitable for microwave soft substrate applications. A microstrip patch antenna is designed and fabricated using the HDPE-0.5 volume fraction ZrSiO4 substrate and the antenna parameters are investigated. PMID:25981704

  5. Shape stabilised phase change materials (SSPCMs): High density polyethylene and hydrocarbon waxes

    SciTech Connect

    Mu, Mulan E-mail: m.basheer@qub.ac.uk; Basheer, P. A. M. E-mail: m.basheer@qub.ac.uk; Bai, Yun; McNally, Tony

    2014-05-15

    Shape stabilised phase change materials (SSPCMs) based on high density polyethylene (HDPE) with high (HPW, T{sub m}=56-58 °C) and low (L-PW, T{sub m}=18-23 °C) melting point waxes were prepared by melt-mixing in a twin-screw extruder and their potential in latent heat thermal energy storage (LHTES) applications for housing assessed. The structure and morphology of these blends were investigated by scanning electron microscopy (SEM). Both H-PW and L-PW were uniformly distributed throughout the HDPE matrix. The melting point and latent heat of the SSPCMs were determined by differential scanning calorimetry (DSC). The results demonstrated that both H-PW and L-PW have a plasticisation effect on the HDPE matrix. The tensile and flexural properties of the samples were measured at room temperature (RT, 20±2 °C) and 70 °C, respectively. All mechanical properties of HDPE/H-PW and HDPE/L-PW blends decreased from RT to 70 °C. In all instances at RT, modulus and stress, irrespective of the mode of deformation was greater for the HDPE/H-PW blends. However, at 70 °C, there was no significant difference in mechanical properties between the HDPE/H-PW and HDPE/L-PW blends.

  6. PORTSMOUTH ON-SITE DISPOSAL CELL HIGH DENSITY POLYETHYLENE GEOMEMBRANE LONGEVITY

    SciTech Connect

    Phifer, M.

    2012-01-31

    It is anticipated that high density polyethylene (HDPE) geomembranes will be utilized within the liner and closure cap of the proposed On-Site Disposal Cell (OSDC) at the Portsmouth Gaseous Diffusion Plant. The likely longevity (i.e. service life) of HDPE geomembranes in OSDC service is evaluated within the following sections of this report: (1) Section 2.0 provides an overview of HDPE geomembranes, (2) Section 3.0 outlines potential HDPE geomembranes degradation mechanisms, (3) Section 4.0 evaluates the applicability of HDPE geomembrane degradation mechanisms to the Portsmouth OSDC, (4) Section 5.0 provides a discussion of the current state of knowledge relative to the longevity (service life) of HDPE geomembranes, including the relation of this knowledge to the Portsmouth OSDC, and (5) Section 6.0 provides summary and conclusions relative to the anticipated service life of HDPE geomembranes in OSDC service. Based upon this evaluation it is anticipated that the service life of HDPE geomembranes in OSDC service would be significantly greater than the 200 year service life assumed for the OSDC closure cap and liner HDPE geomembranes. That is, a 200 year OSDC HDPE geomembrane service life is considered a conservative assumption.

  7. Effect of cooling rate on the properties of high density polyethylene/multi-walled carbon nanotube composites

    SciTech Connect

    Xiang, Dong; Harkin-Jones, Eileen; Linton, David

    2015-05-22

    High density polyethylene (HDPE)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by melt mixing using twin-screw extrusion. The extruded pellets were compression moulded at 200°C for 5min followed by cooling at different cooling rates (20°C/min and 300°C/min respectively) to produce sheets for characterization. Scanning electron microscopy (SEM) shows that the MWCNTs are uniformly dispersed in the HDPE. At 4 wt% addition of MWCNTs composite modulus increased by over 110% compared with the unfilled HDPE (regardless of the cooling rate). The yield strength of both unfilled and filled HDPE decreased after rapid cooling by about 10% due to a lower crystallinity and imperfect crystallites. The electrical percolation threshold of composites, irrespective of the cooling rate, is between a MWCNT concentration of 1∼2 wt%. Interestingly, the electrical resistivity of the rapidly cooled composite with 2 wt% MWCNTs is lower than that of the slowly cooled composites with the same MWCNT loading. This may be due to the lower crystallinity and smaller crystallites facilitating the formation of conductive pathways. This result may have significant implications for both process control and the tailoring of electrical conductivity in the manufacture of conductive HDPE/MWCNT nanocomposites.

  8. Impact of using high-density polyethylene geomembrane layer as landfill intermediate cover on landfill gas extraction.

    PubMed

    Chen, Zezhi; Gong, Huijuan; Zhang, Mengqun; Wu, Weili; Liu, Yu; Feng, Jin

    2011-05-01

    Clay is widely used as a traditional cover material for landfills. As clay becomes increasingly costly and scarce, and it also reduces the storage capacity of landfills, alternative materials with low hydraulic conductivity are employed. In developing countries such as China, landfill gas (LFG) is usually extracted for utilization during filling stage, therefore, the intermediate covering system is an important part in a landfill. In this study, a field test of LFG extraction was implemented under the condition of using high-density polyethylene (HDPE) geomembrane layer as the only intermediate cover on the landfill. Results showed that after welding the HDPE geomembranes together to form a whole airtight layer upon a larger area of landfill, the gas flow in the general pipe increased 25% comparing with the design that the HDPE geomembranes were not welded together, which means that the gas extraction ability improved. However as the heat isolation capacity of the HDPE geomembrane layer is low, the gas generation ability of a shallow landfill is likely to be weakened in cold weather. Although using HDPE geomembrane layer as intermediate cover is acceptable in practice, the management and maintenance of it needs to be investigated in order to guarantee its effective operation for a long term. PMID:21232931

  9. Porous high-density polyethylene in functional rhinoplasty: Excellent long-term aesthetic results and safety

    PubMed Central

    Kim, Young Hyo; Jang, Tae Young

    2014-01-01

    BACKGROUND: Experience with the use of porous high-density polyethylene (PHDPE) for reconstruction of the nasal framework has been limited. OBJECTIVE: To confirm the safety and utility of PHDPE by analyzing aesthetic outcomes and assessing the frequency of complication related to PHDPE in a large, population-based, long-term follow-up study. METHODS: A total of 151 patients who had undergone septoplasty and/or functional rhinoplasty using PHDPE were enrolled. PHDPE sheets were used for diverse purposes such as septal extension graft, spreader graft, columellar strut or dorsal augmentation graft. After a long-term follow-up period (mean [± SD] 39.5±27.8 months; range six to 101 months), postoperative aesthetic outcome was evaluated objectively (by independent surgeons) and subjectively (patient self-report). Complications related to PHDPE were estimated through review of medical records. RESULTS: The most common use of the PHDPE graft was for septal extension (n=80 [42.6%]) and spreader graft (n=58 [30.9%]). Results of aesthetic evaluation by surgeons were excellent in 61 cases (40.4%), good in 54 (35.8%) and fair in 34 (22.5%). According to patient self-report, 100 were ‘satisfied’ (66.2%) and 36 rated their new profile as ‘better than the preoperative profile’ (23.8%). Complications were reported in six cases (4.0% [five cases of extrusion and one case of infection]). All complications were resolved after the surgical removal of PHDPE sheets under local anesthesia. CONCLUSION: The present study demonstrated that PHDPE could be used in functional primary rhinoplasty with excellent long-term aesthetic results and safety. PMID:25152641

  10. Perfluorinated carboxylic acids in directly fluorinated high-density polyethylene material.

    PubMed

    Rand, Amy A; Mabury, Scott A

    2011-10-01

    Perfluorinated carboxylic acids (PFCAs) are ubiquitous in the environment and have been detected in human blood worldwide. One potential route is direct exposure to PFCAs through contact with polymers that have been fluorinated through a process referred to as direct fluorination. PFCAs are hypothesized to be reaction byproducts of direct fluorination when trace amounts of oxygen are present. The objective of this research was to investigate whether PFCAs could be measured in directly fluorinated high-density polyethylene (HDPE) bottles. PFCAs were quantified using Soxhlet extraction with methanol, followed by LC-MS/MS analysis. Total concentrations of PFCAs ranged from 8.5 ± 0.53 to 113 ± 2.5 ng/bottle (1 L), with the short-chain PFCAs, perfluoropropanoic, perfluorobutanoic, perfluoropentanoic, and perfluorohexanoic acids, being the dominant congeners observed. Relative PFCA concentrations varied depending on fluorination level. Structural isomers were detected using (19)F NMR and are hypothesized to have formed during the fluorination process; NMR data revealed the linear isomer typically comprised 55% of the examined sample. Internally branched, isopropyl branched, and t-butyl PFCA isomers of varying chain length were also identified. Electrochemical fluorination was previously thought to be the only source of branched PFCA isomers. The observation here of branched isomers suggests direct fluorination may be an additional source of exposure to these chemicals. The purpose of this study was to measure PFCAs in directly fluorinated material, serving as a previously unidentified source contributing to the environmental load of PFCAs, with potential for human exposure. PMID:21688793

  11. Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

    NASA Astrophysics Data System (ADS)

    Aras, Neny Rasnyanti M.; Arcana, I. Made

    2015-09-01

    An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm-1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese stearate

  12. Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

    SciTech Connect

    Aras, Neny Rasnyanti M. Arcana, I Made

    2015-09-30

    An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm{sup −1} which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese

  13. Wear of the high-density polyethylene socket in total hip arthroplasty and its role in endosteal cavitation.

    PubMed

    Wroblewski, B M

    1997-01-01

    High-density polyethylene (HDP) has been used in clinical practice in total hip replacement since its introduction by Charnley in November 1962. Fears are being expressed that this may be the weakest link and the ultimate cause of failure of the arthroplasty. Long-term clinical experience suggests that loosening may be the primary cause while the presence of HDP wear particles is secondary. Healing of endosteal cavities can take place in the presence of HDP wear particles. PMID:9141896

  14. Degradation of lindane and hexachlorobenzene in supercritical carbon dioxide using palladium nanoparticles stabilized in microcellular high-density polyethylene.

    PubMed

    Wu, Bei-Zen; Chen, GuanYu; Yak, HwaKwang; Liao, Weisheng; Chiu, KongHwa; Peng, Shie-Ming

    2016-06-01

    Palladium nanoparticles stabilized in microcellular high-density polyethylene prepared through supercritical foaming, supercritical impregnation, and H2 reduction are used for the hydrodechlorination of lindane and hexachlorobenzene in supercritical carbon dioxide below 100 °C. Both lindane and hexachlorobenzene can be almost 100% transformed to cyclohexane in 1 h. Reaction intermediates, such as lower chlorinated products or benzene, are not observed or exist in trace amount indicating that most of them may undergo reactions without leaving the metal surface. PMID:26994428

  15. Shear-horizontal surface acoustic wave phononic device with high density filling material for ultra-low power sensing applications

    SciTech Connect

    Richardson, M.; Bhethanabotla, V. R.; Sankaranarayanan, S. K. R. S.

    2014-06-23

    Finite element simulations of a phononic shear-horizontal surface acoustic wave (SAW) sensor based on ST 90°-X Quartz reveal a dramatic reduction in power consumption. The phononic sensor is realized by artificially structuring the delay path to form an acoustic meta-material comprised of a periodic microcavity array incorporating high-density materials such as tantalum or tungsten. Constructive interference of the scattered and secondary reflected waves at every microcavity interface leads to acoustic energy confinement in the high-density regions translating into reduced power loss. Tantalum filled cavities show the best performance while tungsten inclusions create a phononic bandgap. Based on our simulation results, SAW devices with tantalum filled microcavities were fabricated and shown to significantly decrease insertion loss. Our findings offer encouraging prospects for designing low power, highly sensitive portable biosensors.

  16. A Major Intermediate Component in Drawn High-Density Polyethylene Identified by Solid-State NMR

    NASA Astrophysics Data System (ADS)

    Mowery, Daniel; Schmidt-Rohr, Klaus

    2001-03-01

    In a commercial polyethylene (HDPE) highly drawn at 295 K, a distinct morphological component intermediate to the crystalline and the almost isotropic amorphous phases has been identified by solid-state nuclear magnetic resonance (NMR). This intermediate component accounts for nearly 25% of the material bulk, exceeding the amorphous fraction at the highest draw ratios. In the neat isotropic material examined for reference, the NMR-derived composition shows excellent agreement with other techniques. 13C NMR isotropic chemical shifts of the intermediate component, whose signal was selected using an “inverse T1,C filter”, prove chains of nearly all-trans conformations; the line width indicates significant disorder. Reduction of dipolar couplings and the chemical-shift anisotropy show fast rotations of 30 50 deg. amplitude around the chain axes. The degree of orientation of the chain axes is high. Spin diffusion experiments suggest that the intermediate component consists mostly of extended chain bundles closely associated with the amorphous phase (tie-molecule bundles ?).

  17. Atomic force microscopic study of the structure of high-density polyethylene deformed in liquid medium by crazing mechanism.

    PubMed

    Bagrov, D V; Yarysheva, A Y; Rukhlya, E G; Yarysheva, L M; Volynskii, A L; Bakeev, N F

    2014-02-01

    A procedure has been developed for the direct atomic force microscopic (AFM) examination of the native structure of high-density polyethylene (HDPE) deformed in an adsorption-active liquid medium (AALM) by the crazing mechanism. The AFM investigation has been carried out in the presence of a liquid medium under conditions preventing deformed films from shrinkage. Deformation of HDPE in AALM has been shown to proceed through the delocalized crazing mechanism and result in the development of a fibrillar-porous structure. The structural parameters of the crazed polymer have been determined. The obtained AFM images demonstrate a nanosized nonuniformity of the deformation and enable one to observe the structural rearrangements that take place in the deformed polymer after removal of the liquid medium and stress relaxation. A structural similarity has been revealed between HDPE deformed in the AALM and hard elastic polymers. PMID:24283329

  18. Solidification behavior of high-density polyethylene (HDPE) during injection molding: Correlation between crystallization kinetics and thermal gradient field

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Deng, Yan-Li; Li, Gui-Jing; Miao, Ji-Bin; Xia, Ru; Qian, Jia-Sheng; Chen, Peng; Liu, Jing-Wang

    2015-07-01

    This work mainly investigated the effect of thermal field on the crystallization kinetics of high-density polyethylene (HDPE) during injection molding (IM) process. The thickness X = 0.4 was found to be a crucial location heavily influenced by thermal conduction. The temperature decay tended to be stable, with limited variation of the crystallization rate when X > 0.4. It was observed that the crystallization rate was in good proportion to the cooling rate (ϕ). Our experimental finding showed that the consequence of relative crystallinity (χ) was in agreement with that of the secondary temperature difference (STD). This study is practically significant to the further investigation on the relationship among “processing-structure-property” of polymeric materials.

  19. Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

    SciTech Connect

    Ferreto, H. F. R. E-mail: ana-feitoza@yahoo.com.br; Oliveira, A. C. F. E-mail: ana-feitoza@yahoo.com.br; Parra, D. F. E-mail: ablugao@ipen.br; Lugão, A. B. E-mail: ablugao@ipen.br; Gaia, R.

    2014-05-15

    The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of {sup 60}Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

  20. Thermal and mechanical properties of e-beam irradiated butt-fusion joint in high-density polyethylene pipes

    NASA Astrophysics Data System (ADS)

    Vijayan, Vipin; Pokharel, Pashupati; Kang, Min Kwan; Choi, Sunwoong

    2016-05-01

    The effects of electron beam irradiation on the thermal and mechanical properties of a butt-fusion joint in high density polyethylene (HDPE) pipes were investigated. Differential scanning calorimetry, X-ray diffraction, and Fourier transform infra-red spectroscopy of welded samples revealed the changes of crystallinity due to the cross linking effect of electron beam irradiation. The suppression of the degree of crystallinity with increasing the irradiation dose from 0 kGy to 500 kGy indicated that the e-beam radiation induced cross-links among the polymer chains at the weld zone. The cross-link junction at the joint of HDPE pipe prevented chain folding and reorganization leading to the formation of imperfect crystallites with smaller size and also less in content. Tensile test of the welded samples with different dose of e-beam irradiation showed the increased values of the yield stress and Young's modulus as a function of irradiation dose. On the other hand, the elongation at break diminished clearly with increasing the irradiation doses.

  1. Achromobacter xylosoxidans as a new microorganism strain colonizing high-density polyethylene as a key step to its biodegradation.

    PubMed

    Kowalczyk, Anna; Chyc, Marek; Ryszka, Przemysław; Latowski, Dariusz

    2016-06-01

    This study presents results of research on isolation new bacteria strain Achromobacter xylosoxidans able to effect on the structure of high-density polyethylene (HDPE), polymer resistant to degradation in environment. New strain of A. xylosoxidans PE-1 was isolated from the soil and identified by analysis of the 16S ribosome subunit coding sequences. The substance to be degraded was HDPE in the form of thin foil films. The foil samples were analyzed with Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) as well as scanning electron microscope (SEM), and the results revealed degradation of chemical structure of HDPE. About 9 % loss of weight was also detected as a result of A. xylosoxidans PE-1 effect on HDPE foil. On the basis of comparative spectral analysis of the raw material before the bacteria treatment and the spectrum from a spectra database, it was assumed that the HDPE was the only source of carbon and energy for the microorganisms. No fillers or other additives used in the plastic processing were observed in HDPE before experiments. This is the first communication showing that A. xylosoxidans is able to modify chemical structure of HDPE, what was observed both on FTIR, in mass reduction of HDPE and SEM analysis. We also observed quite good growth of the bacteria also when the HDPE was the sole carbon source in the medium. These results prove that A. xylosoxidans is an organism worth applying in future HDPE biodegradation studies. PMID:27072033

  2. Enhanced diesel fuel fraction from waste high-density polyethylene and heavy gas oil pyrolysis using factorial design methodology.

    PubMed

    Joppert, Ney; da Silva, Alexsandro Araujo; da Costa Marques, Mônica Regina

    2015-02-01

    Factorial Design Methodology (FDM) was developed to enhance diesel fuel fraction (C9-C23) from waste high-density polyethylene (HDPE) and Heavy Gas Oil (HGO) through co-pyrolysis. FDM was used for optimization of the following reaction parameters: temperature, catalyst and HDPE amounts. The HGO amount was constant (2.00 g) in all experiments. The model optimum conditions were determined to be temperature of 550 °C, HDPE = 0.20 g and no FCC catalyst. Under such conditions, 94% of pyrolytic oil was recovered, of which diesel fuel fraction was 93% (87% diesel fuel fraction yield), no residue was produced and 6% of noncondensable gaseous/volatile fraction was obtained. Seeking to reduce the cost due to high process temperatures, the impact of using higher catalyst content (25%) with a lower temperature (500 °C) was investigated. Under these conditions, 88% of pyrolytic oil was recovered (diesel fuel fraction yield was also 87%) as well as 12% of the noncondensable gaseous/volatile fraction. No waste was produced in these conditions, being an environmentally friendly approach for recycling the waste plastic. This paper demonstrated the usefulness of using FDM to predict and to optimize diesel fuel fraction yield with a great reduction in the number of experiments. PMID:25532672

  3. Influence of γ-ray modified MWCNTs on the structural and thermal properties of high-density polyethylene

    NASA Astrophysics Data System (ADS)

    Ghafoor, Bilal; Mehmood, Malik Sajjad; Shahid, Umair; Baluch, Mansoor A.; Yasin, Tariq

    2016-08-01

    This study aims to investigate the influence of adding 100 kGy γ-irradiated multi wall carbon nano tubes (MWCNTs) on the structural and thermal properties of high-density polyethylene (HDPE). The effects of further γ-irradiation in the presence of γ-MWCNTs on aforementioned properties have also been investigated. FTIR spectroscopic measurements of HDPE and HDPE/γ-MWCNTs composites reveal that modification of MWCNTs with ≤100 kGy of γ-dose reduces its efficiency as free radical quencher. This behavior is found to increase further with the increase in the concentration of γ-MWCNTs. Wide angle X-ray diffraction (WAXD) data shows a decrease in percent crystallinity and shifting of crystalline peaks toward lower values of 2θ angles. This behavior is mainly attributed to the oxidation induced due to residual free radicals. Thermal analysis reveals that addition of γ-MWCNTs decreases the thermal stability as far as onset thermal degradation temperature, percent crystallinity, and melting temperature of UHMWPE/γ-MWCNTs. In addition to this, gel content measurements show that insoluble percentage of UHMWPE is higher with the incorporation γ-MWCNTs and further irradiation. The gel contents are found to improve up to 29% and 60%, respectively with the incorporation of γ-MWCNTs and further irradiation.

  4. Oxygen-sensitive phosphorescent nanomaterials produced from high-density polyethylene films by local solvent-crazing.

    PubMed

    Toncelli, Claudio; Arzhakova, Olga V; Dolgova, Alla; Volynskii, Aleksandr L; Bakeev, Nikolai F; Kerry, Joe P; Papkovsky, Dmitri B

    2014-02-01

    Discrete solid-state phosphorescent oxygen sensors produced by local solvent-crazing of high density polyethylene films are described. The simple spotting of dye solution followed by tensile drawing of the polymer substrate provides uniform nanostructures with good spatial control, effective encapsulation of dye molecules, and quenchability by O2. The dye-polymer composite sensors prepared using toluene as a solvent and stabilized by annealing at high temperature, show moderate optical signals, near-optimal sensitivity to O2 (RSD at 21 KPa 1.9%), and reproducible phosphorescence lifetime readings. Calibration experiments performed over 0-25 kPa O2 and 10-30 °C temperatures ranges reveal linear Stern-Volmer plots and temperature dependences and minimal effect of humidity on sensor calibration. The high degree of lateral and in-depth homogeneity of these O2-sensitive materials was confirmed by high-resolution atomic force and wide-field optical microscopy, including 2D and 3D phosphorescence lifetime imaging. PMID:24422456

  5. Parameterization of an interfacial force field for accurate representation of peptide adsorption free energy on high-density polyethylene

    PubMed Central

    Abramyan, Tigran M.; Snyder, James A.; Yancey, Jeremy A.; Thyparambil, Aby A.; Wei, Yang; Stuart, Steven J.; Latour, Robert A.

    2015-01-01

    Interfacial force field (IFF) parameters for use with the CHARMM force field have been developed for interactions between peptides and high-density polyethylene (HDPE). Parameterization of the IFF was performed to achieve agreement between experimental and calculated adsorption free energies of small TGTG–X–GTGT host–guest peptides (T = threonine, G = glycine, and X = variable amino-acid residue) on HDPE, with ±0.5 kcal/mol agreement. This IFF parameter set consists of tuned nonbonded parameters (i.e., partial charges and Lennard–Jones parameters) for use with an in-house-modified CHARMM molecular dynamic program that enables the use of an independent set of force field parameters to control molecular behavior at a solid–liquid interface. The R correlation coefficient between the simulated and experimental peptide adsorption free energies increased from 0.00 for the standard CHARMM force field parameters to 0.88 for the tuned IFF parameters. Subsequent studies are planned to apply the tuned IFF parameter set for the simulation of protein adsorption behavior on an HDPE surface for comparison with experimental values of adsorbed protein orientation and conformation. PMID:25818122

  6. Novel cholesterol feeding strategy enables a high-density cultivation of cholesterol-dependent NS0 cells in linear low-density polyethylene-based disposable bioreactors.

    PubMed

    Tao, Yiwen; Yusuf-Makagiansar, Helena; Shih, Jennifer; Ryll, Thomas; Sinacore, Marty

    2012-08-01

    We have developed a perfusion-based high cell density (HD) cell banking and inoculum expansion procedure for a cholesterol-dependent NS0 myeloma cell line using linear low-density polyethylene-based disposable bioreactors. Challenges associated with cholesterol-polymer interactions, which suppress cholesterol-dependent NS0 myeloma cell growth, were overcome using a novel cholesterol feeding protocol that included a combination of two cholesterol formulations: an ethanol-based formulation and an aqueous formulation. Using a cholesterol feed optimized for HD cell culture in a disposable bioreactor perfusion system, cell densities of >25 × 10(6) viable cells/ml at ≥ 90 % cell viability were achieved. Vials of high density cell banks were created by filling 90-100 × 10(6) viable cells/ml in 5 ml cryotube vials. Implementation of the HD cell banks enabled a significant reduction in the number of step operations in the inoculum expansion phase in a large-scale manufacturing setting. PMID:22481299

  7. High density polyethylene (HDPE)/poly(ethylene terephthalate) (PET) polymer blend studies related to recycling co-mingled plastics

    NASA Astrophysics Data System (ADS)

    Tsai, Pang-Yen

    Polymer blends of virgin high density polyethylene (HDPE) and poly(ethylene terephthalate) (PET) were studied as an attempt to relate the microstructure to the mechanical properties of the blends. The virgin blends were prepared by extrusion and then injection molded into specimens for characterization. Two of the virgin blends were tested for possible compatibilization using a styrene-ethylene-butylene-styrene (SEBS) block copolymer. In addition, six blends of post-consumer resins (PCRs) of HDPE and PET were included in this work for comparison. The moduli of the virgin blends showed positive deviation from those expected from the rule of mixtures. The synergism of the composite moduli can be explained partly by a Poisson's effect. Yield strengths of the blends molded at low injection chamber temperatures (200sp°, 230sp°, and 250sp°C) followed the rule of mixtures well, because PET filaments found in the composites had very high length to diameter ratios. When the injection chamber temperature was above the PET melting point (˜254sp°C), PET filaments were found to break down into particles, and the yield strengths of the blends coincided with the values expected from the inverse rule of mixtures. Impact strengths of the virgin blends were much less than that of a HDPE homopolymer due to poor interfacial bonding between HDPE and PET. Compatibilization appeared to be advantageous since it dramatically improved the impact strength of the virgin blends. SEM micrographs of impact fractured surfaces revealed that the improved adhesion from compatibilization and the presence of numerous uniaxially aligned PET filaments in the HDPE substrate can account for the significant increases in fracture resistance of the compatibilized blends. Mechanical performance of the PCRs was inferior to that of the virgin blends. Aside from polymer degradation and contamination due to repeated processing and handling, absence of PET filaments and interfacial bonding could be

  8. Effect of admixed high-density polyethylene (HDPE) spheres on contraction stress and properties of experimental composites.

    PubMed

    Ferracane, J L; Ferracane, L L; Braga, R R

    2003-07-15

    Additives that provide stress relief may be incorporated into dental composites to reduce contraction stress (CS). This study attempted to test the hypothesis that conventional fillers could be replaced by high-density polyethylene (HDPE) spheres in hybrid and nanofill composites to reduce CS, but with minimal effect on mechanical properties. Nanofill and hybrid composites were made from a Bis-GMA/TEGDMA resin having either all silica nanofiller or 75 wt.% strontium glass + 5 wt.% silica and replacing some of the nanofiller or the glass with 0%, 5% (hybrid only), 10% or 20 wt.% HDPE. The surface of the HDPE was either left untreated or had a reactive gas surface treatment (RGST). Contraction stress (CS) was monitored for 10 min in a tensilometer (n = 5) after light curing for 60 s at 390 mW/cm(2). Other specimens (n = 5) were light cured 40 s from two sides in a light-curing unit and aged 1 d in water before testing fracture toughness (K(Ic)), flexure strength (FS), and modulus (E). Results were analyzed by ANOVA with Tukey's multiple comparison test at p < 0.05. There was no difference between composites with RGST and untreated HDPE except for FS-10% HDPE hybrid (RGST higher). An increased level of HDPE reduced contraction stress for both types of composites. Flexure strength, modulus (hybrid only), and fracture toughness were also reduced as the concentration of HDPE increased. SEM showed evidence for HDPE debonding and plastic deformation during fracture of the hybrid composites. In conclusion, the addition of HDPE spheres reduces contraction stress in composites, either through stress relief or a reduction in elastic modulus. PMID:12808590

  9. Methyl bromide emission from fields partially covered with a high-density polyethylene and a virtually impermeable film

    SciTech Connect

    Wang, D.; Yates, S.R.

    1998-09-01

    Recent field studies in the interior valley of southern California have indicated that 56--73% of methyl bromide (MeBr) used in soil fumigation is lost to atmospheric emission when the fields are covered completely with a high-density polyethylene (HDPE) film. The emission can be reduced to less than 5% when a virtually impermeable film or Hytibar is used to cover the fields. This study was conducted to determine MeBr emission from bedded field plots where only the beds were covered with a HDPE or a virtually impermeable plastic film. The results provide an assessment on MeBr emission from field beds partially covered with the HDPE film and the suitability of using a virtually impermeable film for emission reduction. Methyl bromide gas was applied to replicated field beds covered with either a HDPE or the Hytibar film. The films were removed 6 days after MeBr application. Replicated soil cores were taken from different locations of the field beds, 20 days after MeBr application, for the determination of soil bromide ion concentrations. The total amount of MeBr degraded from each plot was calculated from the measured bromide ion concentrations, and the potential emission was determined as the difference between the amount of applied and that of degraded. Results indicated that the potential emission from this bedded system was about 95% for the HDPE treatment and 90% for the Hytibar-covered plots. Regardless of the small improvement with the virtually impermeable film, the experiment clearly indicates that partially covering the field with either a HDPE or a virtually impermeable film would result in unacceptably high emission losses.

  10. From macroplastic to microplastic: Degradation of high-density polyethylene, polypropylene, and polystyrene in a salt marsh habitat.

    PubMed

    Weinstein, John E; Crocker, Brittany K; Gray, Austin D

    2016-07-01

    As part of the degradation process, it is believed that most plastic debris becomes brittle over time, fragmenting into progressively smaller particles. The smallest of these particles, known as microplastics, have been receiving increased attention because of the hazards they present to wildlife. To understand the process of plastic degradation in an intertidal salt marsh habitat, strips (15.2 cm × 2.5 cm) of high-density polyethylene, polypropylene, and extruded polystyrene were field-deployed in June 2014 and monitored for biological succession, weight, surface area, ultraviolet (UV) transmittance, and fragmentation. Subsets of strips were collected after 4 wk, 8 wk, 16 wk, and 32 wk. After 4 wk, biofilm had developed on all 3 polymers with evidence of grazing periwinkles (Littoraria irrorata). The accreting biofilm resulted in an increased weight of the polypropylene and polystyrene strips at 32 wk by 33.5% and 167.0%, respectively, with a concomitant decrease in UV transmittance by approximately 99%. Beginning at 8 wk, microplastic fragments and fibers were produced from strips of all 3 polymers, and scanning electron microscopy revealed surface erosion of the strips characterized by extensive cracking and pitting. The results suggest that the degradation of plastic debris proceeds relatively quickly in salt marshes and that surface delamination is the primary mechanism by which microplastic particles are produced in the early stages of degradation. Environ Toxicol Chem 2016;35:1632-1640. © 2016 SETAC. PMID:26992845

  11. Investigation of pulsed light for terminal sterilization of WFI filled blow/fill/seal polyethylene containers.

    PubMed

    Dunn, J; Burgess, D; Leo, F

    1997-01-01

    A study was performed to assess the ability of pulsed light to sterilize water for injection in blow/fill/seal polyethylene containers. Pulsed light uses intense, short duration flashes of broad spectrum white light to produce high levels of microbial kill. In a first phase of testing, containers of 0.5, 5, 15, and 120 mL nominal volume were inoculated with Bacillus pumilus endospores, Bacillus subtilus variety niger strain globigii endospores, Bacillus stearothermophilus endospores, and Aspergillus niger conidiospores. Approximately 10(6) colony forming units of each test spore were individually inoculated into 22 replicate containers of each sample volume. Two of these containers served as inoculation recovery controls, and 10 were treated using each of two pulsed light exposure methods: single-sided treatment, or treatment within a reflective cavity. Both treatments employed flashes of intense broad spectrum pulsed light delivered at one flash per second. Cavity treatment used 10 flashes to treat each container within a reflective cavity containing a single lamp. Cavity treatment yielded no recoverable survivors for any of the challenge spores from the contents of any of the 160 total samples. Single-sided treatment used 20 approximately 1-J/cm2 flashes from a single lamp-reflector projecting onto one side of the container. Single-sided treatment yielded no recoverable survivors from the contents of the containers for any of the bacterial endospores tested, but Aspergillus niger survival was detected in 4 of the 40 single-side treated samples. A second phase of tests examined the pulsed light inactivation of Bacillus pumilus spores for a range of inoculation levels. High levels of Bacillus pumilus spore kill were obtained using only a few cavity flashes. The results show that pulsed light can provide high levels of microbial lethality and possesses potential for use as a terminal sterilization method for water for injection in filled, sealed polyethylene

  12. Investigation of the structure of cold-drawn high-density polyethylene using solid-state NMR

    NASA Astrophysics Data System (ADS)

    Mowery, Daniel Michael

    In this dissertation, the cold-drawing response of a commercial high-density polyethylene (HDPE) resin has been studied using solid-state nuclear magnetic resonance (NMR) spectroscopy and variety of other complementary techniques. Melt-crystallized, isotropic samples of the HDPE have been drawn to various extensions at ambient temperature (21°C) and at a relatively slow strain rate (0.0013 s-1). Using solid-state NMR, the first unambiguous evidence for a major morphological component intermediate to the crystalline and amorphous domains in the cold-drawn HDPE microstructure has been found. Employing an 'inverse 13 C T1 filter' and other filtering techniques, signals from the various components have been selected and compared. The intermediate component comprises chains of all-trans conformation but with significant disorder in packing. The chains show fast, intermediate-amplitude motions about their axes and are generally aligned with the draw direction, but with a greater distribution of orientation angles relative to crystalline phase. A quantitative 13C NMR procedure has been utilized in the analysis of morphological component composition during cold drawing. In the undeformed material, the NMR-derived composition shows excellent agreement with other common techniques. The mass fraction of the intermediate component has been measured by NMR to be as high as 35% in the cold-drawn HDPE, greater than the contributions from the amorphous domains and monoclinic crystals. The intermediate component content dramatically increases by 240% just after necking, along with a doubling in the monoclinic crystals. At the same time, decreases of about 25% in the total crystalline and amorphous phases occur. A general re-ordering in the microstructure takes place during neck propagation and strain hardening. The total crystallinity rises by about 8%, with a corresponding decrease in the monoclinic crystals (50%) and amorphous material (30%). Based on 1H spin diffusion data, a

  13. Particle Filled Polyethylene Composites Used in the Technology of Rotational Moulding

    NASA Astrophysics Data System (ADS)

    Bútora, Peter; Náplava, Antonín; Ridzoň, Martin; Bílik, Jozef; Tittel, Viktor

    2011-01-01

    The submitted article discusses rotational moulding technology and filled plastics. For testing, linear low density polyethylene filled with talc was used. The materials tested varied way of mixing the filler into the polymer. For the prepared samples were evaluated by tensile, elongation, melt flow index, density, Shore hardness and Vicat softening temperature. Experiments showed that, in principle, it is possible to produce rotational moulding technology filled thermoplastics.

  14. Morphological Considerations in TTF-TCNQ filled Polyethylene Composites

    NASA Astrophysics Data System (ADS)

    Genetti, W. B.; Lamirand, R.; Grady, B. P.

    1998-03-01

    Composites of LDPE filled with the charge transfer complex tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) were produced by solution casting. Wide angle x-ray scattering and stress relaxation were used to show the effect of filler addition and uniaxial stretching on the PE crystallite orientation. Even without stretching, the films were slightly oriented, but the direction of orientation changed with TTF-TCNQ concentration. The composites with low filler loading were slightly oriented perpendicular to the casting direction, where as the highly loaded composites were oriented slightly parallel to the casting surface. This shift occurred abruptly at the end of the critical region. Orientation in the stretched films increased with increasing draw ratio. However, the increase in orientation resulting from uniaxial stretching decreased with increasing concentration. One explanation for this behavior is that the addition of TTF-TCNQ to the polymer causes a decrease in the relaxation time. This observation was consistent with a drop in initial relaxation times calculated from stress relaxation experiments.

  15. Characterization of solidified radioactive waste and container due to the incorporation of high density polyethylene granules and powder in mortar matrices

    SciTech Connect

    Peric, A.D.

    1999-07-01

    Powder and granules of the high density polyethylene (PEHD) were used to prepare mortar based matrices for immobilization of radioactive waste materials containing {sup 137}Cs, as well as containers for solidified radioactive waste form. Seven types of matrices, differ due to the percentage of granules and filler material added, were investigated. PEHD powder and granules were added to mortar matrix preparations with the objective of improving physico-chemical characteristics of the radwaste-mortar matrix mixtures, in particular the leach-rate of the immobilized radionuclide, as well as mechanical characteristics either of mortar matrix and container. In this paper, only mechanical strength aspect of the investigated mortar and concrete container formulations, is presented. The equivalent diameter of the PEHD granules used was 2.0 mm. PEHD granules were used to replace 100 volume percent of stone granules, sifted size of 2.0 mm, normally used in the matrix preparation, in order to decrease the porosity and density of the mortar matrix and to avoid segregation of the stone particles at the bottom of the immobilized radioactive waste cylindrical form. PEHD powder, particle size of 250 micrometer, was added as filler to the mortar formulation, replacing 5, 8 and 10 wt% of the total cement weight in matrix formulation and 15 and 18 wt% of the total cement weight in container formulation. Cured samples were investigated on mechanical strength, using 150 MPa hydraulic press, in order to determine influence of added polyethylene granules and powder on samples resistance to mechanical forces that solidified waste materials and concrete containers may experience at the disposal site. Results of performed investigations have shown that samples prepared with polyethylene granules, replacing 100 wt% of the stone granules, have almost twice as much mechanical strength than samples prepared with stone aggregate. Samples prepared with PEHD granules and powder have mechanical

  16. Enhancement of mechanical strength of TiO{sub 2}/high-density polyethylene composites for bone repair with silane-coupling treatment

    SciTech Connect

    Hashimoto, Masami . E-mail: masami@jfcc.or.jp; Takadama, Hiroaki . E-mail: takadama@jfcc.or.jp; Mizuno, Mineo . E-mail: mizuno@jfcc.or.jp; Kokubo, Tadashi . E-mail: kokubo@isc.chubu.ac.jp

    2006-03-09

    Mechanical properties of composites made up of high-density polyethylene (HDPE) and silanated TiO{sub 2} particles for use as a bone-repairing material were investigated in comparison with those of the composites of HDPE with unsilanized TiO{sub 2} particles. The interfacial morphology and interaction between silanated TiO{sub 2} and HDPE were analyzed by means of Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The absorption in spectral bands related to the carboxyl bond in the silane-coupling agent, the vinyl group in the HDPE, and the formation of the ether bond was studied in order to assess the influence of the silane-coupling agent. The SEM micrograph showed that the 'bridging effect' between HDPE and TiO{sub 2} was brought about by the silane-coupling agent. The use of the silane-coupling agent and the increase of the hot-pressing pressure for shaping the composites facilitated the penetration of polymer into cavities between individual TiO{sub 2} particles, which increased the density of the composite. Therefore, mechanical properties such as bending yield strength and Young's modulus increased from 49 MPa and 7.5 GPa to 65 MPa and 10 GPa, respectively, after the silane-coupling treatment and increase in the hot-pressing pressure.

  17. Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acrylonitrile-butadiene rubber

    NASA Astrophysics Data System (ADS)

    Reinholds, Ingars; Kalkis, Valdis; Merijs-Meri, Remo; Zicans, Janis; Grigalovica, Agnese

    2016-03-01

    In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100-300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the kinetics of thermorelaxation and the residual shrinkage stresses of previously oriented (stretched up to 100% at above melting temperature of HDPE and followed by cooling to room temperature) specimens of irradiated HDPE/NBR blends under isometric heating-cooling mode. The compatibility between the both components was enhanced due to the formation of cross-linked sites at amorphous interphase. The results showed increase of mechanical stiffness of composites with increase of irradiation dose. The values of gel fraction compared to thermorelaxation stresses increased with the growth of irradiation dose level, as a result of formation cross-linked sites in amorphous PP/NBR interphase.

  18. Heat transfer performance of a phase-change thermal energy storage water heater using cross-linked high density polyethylene pellets

    SciTech Connect

    Jotshi, C.K.; Klausner, J.F.; Goswami, D.Y.; Hsieh, C.K.; Santhosh, M.K.; Colacino, F.

    1996-12-31

    The objective of this investigation was to develop an efficient water heater that stores thermal energy in a mixture of cross-linked high density polyethylene (HDPE) pellets and propylene glycol. Properties of cross-linked HDPE, such as melting and crystallization temperatures, heat of fusion and crystallization, and volume change were measured in the laboratory. The heat transfer coefficient for the mixture was also measured in a laboratory test. A prototype model of a storage water heater using a mixture of cross-linked HDPE pellets and propylene glycol was designed and fabricated. A copper finned heat transfer coil was used to extract the heat from the storage tank by passing water through it. The heat transfer efficiency (heat extracted by water/heat stored) was measured to be about 70%. To increase the efficiency, the storage unit was modified. In the modified unit, the length of the heat transfer coil was increased and coil spacing optimized. With the modification, the heat transfer efficiency was measured to be about 90%. In addition, a variable heat flux heating element, having high heat flux at the bottom and low heat flux at top, was used to reduce thermal stratification of the propylene glycol/HDPE pellet mixture.

  19. Efficacy of alphacypermethrin-treated high density polyethylene mesh applied to jet stalls housing horses against Culicoides biting midges in South Africa.

    PubMed

    Page, P C; Labuschagne, K; Venter, G J; Schoeman, J P; Guthrie, A J

    2015-05-30

    The efficacy of alphacypermethrin-treated high density polyethylene (HDPE) mesh applied to jet stalls against Culicoides biting midges (Diptera: Ceratopogonidae) was determined by mechanical aspiration of midges from horses and using Onderstepoort 220 V downdraught black light traps in four blocks of a 3 × 2 randomised design under South African field conditions. The alphacypermethrin-treated HDPE mesh applied to the stall significantly (P = 0.008) reduced the number of Culicoides midges, predominantly Culicoides (Avaritia) imicola Kieffer, mechanically aspirated from horses housed in the stall. The mesh reduced the Culicoides midge attack rate in the treated stall compared to the untreated stall and a sentinel horse by 6 times and 14 times, respectively. The number of Culicoides midges and C. imicola collected in light traps from the untreated and alphacypermethrin HDPE mesh-treated stalls did not differ significantly (P = 0.82). Alphacypermethrin-treated HDPE mesh could be used to reduce exposure of horses in jet stalls to Culicoides midges, specifically C. imicola, and the risk of midge-borne Orbivirus transmission. PMID:25794942

  20. Method for assessing lead, cadmium, mercury and arsenic in high-density polyethylene packaging and study of the migration into yoghurt and simulant.

    PubMed

    Kiyataka, Paulo Henrique M; Dantas, Sílvia T; Pallone, Juliana Azevedo Lima

    2014-01-01

    The purpose of this paper was to assess the concentration of lead (Pb), cadmium (Cd), mercury (Hg) and arsenic (As) in high-density polyethylene (HDPE) packaging intended for contact with yoghurt and the migration of these elements using the food itself and 3% acetic acid as a food simulant in accordance to ANVISA, the Brazilian Health Surveillance Agency. In order to perform this study, it was necessary to develop and validate a method by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. For method validation, the parameters linearity, limits of detection (LODs) and quantification (LOQs), accuracy and precision were determined. Fifteen commercial samples of yoghurt, marketed in Campinas - São Paulo (Brazil), were used for the analysis. The packaging and yoghurt were digested in high-pressure ashing equipment (HPA) and the migration of the elements into simulant were determined directly in the solution. The validated method proved adequate and the results obtained showed that all the packaging had levels of Hg and Cd below the LOQ, corresponding to 1.0 and 1.5 μg l(-1), respectively. The highest levels of As and Pb were 0.87 and 462.3 mg kg(-1), respectively. The migration of these elements to the yoghurt after 45 days of contact at 4ºC was below the LOQ for all the samples assessed. The results of specific migration into 3% acetic acid simulant showed the concentrations of Cd, Hg and As below 5, 5 and 10 µg kg(-1), respectively, which are the maximum limits set by ANVISA. However, for three samples the packaging lid showed migration of Pb into simulant ranging from 30.6 to 40.2 μg kg(-1), exceeding the limit set by ANVISA of 10 μg kg(-1). PMID:24444394

  1. Criticality Evaluation of Plutonium-239 Moderated by High-Density Polyethylene in Stainless Steel and Aluminum Containers Suitable for Non-Exclusive Use Transport

    SciTech Connect

    Watson, T T

    2007-08-10

    Research is conducted at the Joint Actinide Shock Physics Experimental Facility (JASPER) on the effects of high pressure and temperature environments on plutonium-239, in support of the stockpile stewardship program. Once an experiment has been completed, it is necessary to transport the end products for interim storage or final disposition. Federal shipping regulations for nonexclusive use transportation require that no more than 180 grams of fissile material are present in at least 360 kilograms of contiguous non-fissile material. To evaluate the conservatism of these regulatory requirements, a worst-case scenario of 180g {sup 239}Pu and a more realistic scenario of 100g {sup 239}Pu were modeled using one of Lawrence Livermore National Laboratory's Monte Carlo transport codes known as COG 10. The geometry consisted of {sup 239}Pu spheres homogeneously mixed with high-density polyethylene surrounded by a cube of either stainless steel 304 or aluminum. An optimized geometry for both cube materials and hydrogen-to-fissile isotope (H/X) ratio were determined for a single unit. Infinite and finite 3D arrays of these optimized units were then simulated to determine if the systems would exceed criticality. Completion of these simulations showed that the optimal H/X ratio for the most reactive units ranged from 800 to 1600. A single unit of either cube type for either scenario would not reach criticality. An infinite array was determined to reach criticality only for the 180g case. The offsetting of spheres in their respective cubes was also considered and showed a considerable decrease in the number of close-packed units needed to reach criticality. These results call into question the current regulations for fissile material transport, which under certain circumstances may not be sufficient in preventing the development of a critical system. However, a conservative, theoretical approach was taken in all assumptions and such idealized configurations may not be likely to

  2. Post-consumer contamination in high-density polyethylene (HDPE) milk bottles and the design of a bottle-to-bottle recycling process.

    PubMed

    Welle, F

    2005-10-01

    Six hundred conventional recycled HDPE flake samples, which were recollected and sorted in the UK, were screened for post-consumer contamination levels. Each analysed sample consisted of 40-50 individual flakes so that the amount of analysed individual containers was in the range 24,000-30,000 post-consumer milk bottles. Predominant contaminants in hot-washed flake samples were unsaturated oligomers, which can be also be found in virgin high-density polyethylene (HDPE) pellet samples used for milk bottle production. In addition, the flavour compound limonene, the degradation product of antioxidant additives di-tert-butylphenol and low amounts of saturated oligomers were found in higher concentrations in the post-consumer samples in comparison with virgin HDPE. However, the overall concentrations in post-consumer recycled samples were similar to or lower than concentration ranges in comparison with virgin HDPE. Contamination with other HDPE untypical compounds was rare and was in most cases related to non-milk bottles, which are <2.1% of the input material of the recycling process. The maximum concentration found in one sample of 1 g was estimated as 130 mg kg(-1), which corresponds to a contamination of 5200-6500 mg kg(-1) in the individual bottle. The recycling process investigated was based on an efficient sorting process, a hot-washing of the ground bottles, and a further deep-cleaning of the flakes with high temperatures and vacuum. Based on the fact that the contamination levels of post-consumer flake samples are similar to virgin HDPE and on the high cleaning efficiency of the super-clean recycling process especially for highly volatile compounds, the recycling process investigated is suitable for recycled post-consumer HDPE bottles for direct food-contact applications. However, hand-picking after automatically sorting is recommended to decrease the amount of non-milk bottles. The conclusions for suitability are valid, provided that the migration testing of

  3. Radiation grafting of acrylamide onto starch-filled low density polyethylene

    NASA Astrophysics Data System (ADS)

    Bagheri, Rouhallah; Naimian, Franak; Sheikh, Nassrin

    1997-04-01

    Acrylamide (AAm) was grafted on the surface of starch-filled low density polyethylene (SLDPE) and low density polyethylene (LDPE) films by the mutual irradiation technique at doses from 0.75 to 5 kGy. The effect of dose, solvents and dihydroxybenzoquinone on the degree of grafting was studied by Fourier transform infrared spectroscopy and the weight measurement method of extracted films at a constant monomer concentration (10% w/w). An ultraviolet spectrophotometer was also used to elucidate the results of the above methods. Grafting on SLDPE and LDPE samples reaches a maximum followed by a slight decrease with increasing dose. A higher degree of grafting was obtained on SLDPE samples compared with that on LDPE. An induction period was observed in the case of the samples prepared in tetrahdyrfuran (THF) as the solvent compared with those in chloroform. Addition of benzene to chloroform and THF (50% v/v) accelerates the rate of AAm grafting on the samples. Dihydroxybenzoquinone inhibits the grafting reactions of the samples especially in the THF solutions. The water uptake measurement of the samples correlates with the degree of grafting.

  4. Development of optimum process for electron beam cross-linking of high density polyethylene thermal energy storage pellets, process scale-up and production of application qualities of material

    NASA Technical Reports Server (NTRS)

    Salyer, I. O.

    1980-01-01

    The electron irradiation conditions required to prepare thermally from stable high density polyethylene (HDPE) were defined. The conditions were defined by evaluating the heat of fusion and the melting temperature of several HDPE specimens. The performance tests conducted on the specimens, including the thermal cycling tests in the thermal energy storage unit are described. The electron beam irradiation tests performed on the specimens, in which the total radiation dose received by the pellets, the electron beam current, the accelerating potential, and the atmospheres were varied, are discussed.

  5. Mechanical and electrical properties of low density polyethylene filled with carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Sabet, Maziyar; Soleimani, Hassan

    2014-08-01

    Carbon nanotubes (CNTs) reveal outstanding electrical and mechanical properties in addition to nanometer scale diameter and high aspect ratio, consequently, making it an ideal reinforcing agent for high strength polymer composites. Low density polyethylene (LDPE)/CNT composites were prepared via melt compounding. Mechanical and electrical properties of (LDPE)/CNT composites with different CNT contents were studied in this research.

  6. Catalytic degradation of high-density polyethylene on an ultrastable-Y zeolite. Nature of initial polymer reactions, pattern of formation of gas and liquid products, and temperature effects

    SciTech Connect

    Manos, G.; Garforth, A.; Dwyer, J.

    2000-05-01

    The catalytic degradation of high-density polyethylene (hdPE) over ultrastable Y zeolite in a semibatch reactor was studied at different heating rates and reaction temperatures. Catalytic degradation of the polymer occurred at much lower temperatures than pure thermal degradation. When gel permeation chromatography was used to determine the molar mass distribution, it was found that solid state reactions occur only in the presence of a catalyst. These reactions change the polymer structure well before the formation of significant amounts of volatile products. The pattern of formation of gaseous and liquid products was studied and found to follow the temperature increase. After the system reached its final temperature, the reaction rate of formation of volatile products decreased rapidly. The product range was typically between C{sub 3} and C{sub 15}. Isobutane and isopentane were the main gaseous products. The liquid product fraction was alkane-rich, as alkenes rapidly undergo bimolecular hydrogen transfer reactions to give alkanes as secondary products.

  7. Mechanical properties of low-density polyethylene filled by graphite nanoplatelets.

    PubMed

    Carotenuto, G; De Nicola, S; Palomba, M; Pullini, D; Horsewell, A; Hansen, T W; Nicolais, L

    2012-12-01

    The mechanical properties of GNP/LDPE nanocomposites (graphite nanoplatelets/low density polyethylene) have been investigated, in order to establish the effect of nanoscale reinforcement within the polymer matrix. Results show that the presence of the filler does not involve a change in the microscopic structure of the polymer. However, on a macroscopic scale, GNPs limit the mobility of the polymer chains, resulting in an increase in stiffness for the final composite. Orientation of GNPs within the LDPE matrix is also an important issue that affects mechanical properties and it has been evaluated by testing nanocomposites made by different manufacturing techniques (compression moulding and blown extrusion). The comparison between the experimental data and the Halpin-Tsai model shows that the orientation of GNPs due to the extrusion process leads to values of tensile modulus higher than that obtained with the randomly oriented disposition resulting from the compression moulding technique. PMID:23128320

  8. Chitosan filled recycled low density polyethylene composite: Melt flow behaviour and thermal degradation properties

    NASA Astrophysics Data System (ADS)

    Lim, B. Y.; Voon, C. H.; Salmah, H.; Nordin, H.

    2016-07-01

    An environmentally friendly composite was fabricated from chitosan and recycled low density polyethylene (rLDPE) with the means of melt mixing at 180 °C. The composites were prepared in different loading (10, 20, 30 and 40 php) of chitosan. Due to the incompatibility between filler and matrix, a coupling agent, Ultraplus TP01, was added into the composites. The melt flow index (MFI) values of rLDPE/chitosan composites decreased with chitosan loading but increased with rise of temperature. With the presence of Ultraplus TP01, MFI values of composites were decreased. The thermal stability of rLDPE/chitosan was reduced with increase of chitosan loading but increased with addition of Ultraplus TP01. It was believed that Ultraplus TP01 had provided better interfacial bonding between chitosan and rLDPE, thus enhanced the thermal stability of rLDPE/chitosan composites.

  9. Spatially revolved high density electroencephalography

    NASA Astrophysics Data System (ADS)

    Wu, Jerry; Szu, Harold; Chen, Yuechen; Guo, Ran; Gu, Xixi

    2015-05-01

    Electroencephalography (EEG) measures voltage fluctuations resulting from ionic current flows within the neurons of the brain. In practice, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, several tens of minutes, as recorded from multiple electrodes placed on the scalp. In order to improve the resolution and the distortion cause by the hair and scalp, large array magnetoencephalography (MEG) systems are introduced. The major challenge is to systematically compare the accuracy of epileptic source localization with high electrode density to that obtained with sparser electrode setups. In this report, we demonstrate a two dimension (2D) image Fast Fourier Transform (FFT) analysis along with utilization of Peano (space-filling) curve to further reduce the hardware requirement for high density EEG and improve the accuracy and performance of the high density EEG analysis. The brain-computer interfaces (BCIs) in this work is enhanced by A field-programmable gate array (FPGA) board with optimized two dimension (2D) image Fast Fourier Transform (FFT) analysis.

  10. High density laser-driven target

    DOEpatents

    Lindl, John D.

    1981-01-01

    A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

  11. Scale effects in tribological properties of solid-lubricating composites made of ultra-high molecular weight polyethylene filled with calcium stearate particles

    NASA Astrophysics Data System (ADS)

    Lurie, S. A.; Volkov-Bogorodskiy, D. B.; Knyzeva, A. G.; Panin, S. V.; Kornienko, L. A.

    2016-04-01

    Friction properties being influenced by scale effects are simulated in the paper by the example of polymer composite material made from Ultra High-Molecular Weight Polyethylenes (UHMWPE) filled by calcium stearate (C36H70CaO4). Of interest are the composites whose mechanical properties and tribotechnical characteristics do not depend monotonically on filler (inclusions) weight fraction. In order to describe the influence of scale effects onto frictional properties the model based on Reiss averaging (model of "weak phase") is employed. It is also suggested that when gradient elasticity theory is applicable the formal analogy between effective friction coefficient for surface heterogeneous structures and effective mechanical properties (compliances) for heterogeneous material can take place. Theoretical dependence to describe nonmonotonic change of effective friction coefficient versus filler concentration was obtained for the polymer composites under study. The suggested expressions might be useful for the sake of properties prognosis of antifriction polymeric materilas.

  12. High density pixel array

    NASA Technical Reports Server (NTRS)

    Wiener-Avnear, Eliezer (Inventor); McFall, James Earl (Inventor)

    2004-01-01

    A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

  13. High density modular avionics packaging

    NASA Astrophysics Data System (ADS)

    Poradish, F.

    Requirements and design configurations for high density modular avionics packaging are examined, with particular attention given to new hardware trends, the design of high-density standard modules (HDSM's), and HDSM requirements. The discussion of the HDSM's covers thermal management, system testability, power supply, and performance specifications. The general design of an integrated HDSM demonstration system currently under construction is briefly described, and some test data are presented.

  14. The characterization of high-density polyethylene/organoclay nanocomposites

    NASA Astrophysics Data System (ADS)

    Rodrigues, Tathiane Cordeiro; Tavares, Maria Inês Bruno; Soares, Igor Lopes; Moreira, Ana M.

    2009-01-01

    Polymeric nanocomposites, which are hybrids of polymers and modified inorganic clay with organic surfactants, are extremely attractive in both science and industry. These materials present improvements in such polymer properties as modulus, heat capacity, thermal stability, flame resistance, and so on. Research has been conducted in recent decades to obtain high-quality materials that can be used in applications like food packing, car components, and combustible cells. Polymeric nanocomposites present many advantages in relation to composites due to the quantity of filler added to the polymer and also to the improved properties. In a composite, the quantity of filler must be as high as possible (i.e., over 30%). In the polymeric nanocomposite the quantity of filler varies from 1% to 5% because of the nanosize of the particles. These nanoparticles often have a large surface area that results in improved polymer-matrix properties.

  15. Laminated thermoplastic composite material from recycled high density polyethylene

    NASA Technical Reports Server (NTRS)

    Liu, Ping; Waskom, Tommy L.

    1994-01-01

    The design of a materials-science, educational experiment is presented. The student should understand the fundamentals of polymer processing and mechanical property testing of materials. The ability to use American Society for Testing and Materials (ASTM) standards is also necessary for designing material test specimens and testing procedures. The objectives of the experiment are (1) to understand the concept of laminated composite materials, processing, testing, and quality assurance of thermoplastic composites and (2) to observe an application example of recycled plastics.

  16. Photoionization and High Density Gas

    NASA Technical Reports Server (NTRS)

    Kallman, T.; Bautista, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We present results of calculations using the XSTAR version 2 computer code. This code is loosely based on the XSTAR v.1 code which has been available for public use for some time. However it represents an improvement and update in several major respects, including atomic data, code structure, user interface, and improved physical description of ionization/excitation. In particular, it now is applicable to high density situations in which significant excited atomic level populations are likely to occur. We describe the computational techniques and assumptions, and present sample runs with particular emphasis on high density situations.

  17. High Density Methane Storage in Nanoporous Carbon

    NASA Astrophysics Data System (ADS)

    Rash, Tyler; Dohnke, Elmar; Soo, Yuchoong; Maland, Brett; Doynov, Plamen; Lin, Yuyi; Pfeifer, Peter; Mriglobal Collaboration; All-Craft Team

    2014-03-01

    Development of low-pressure, high-capacity adsorbent based storage technology for natural gas (NG) as fuel for advanced transportation (flat-panel tank for NG vehicles) is necessary in order to address the temperature, pressure, weight, and volume constraints present in conventional storage methods (CNG & LNG.) Subcritical nitrogen adsorption experiments show that our nanoporous carbon hosts extended narrow channels which generate a high surface area and strong Van der Waals forces capable of increasing the density of NG into a high-density fluid. This improvement in storage density over compressed natural gas without an adsorbent occurs at ambient temperature and pressures ranging from 0-260 bar (3600 psi.) The temperature, pressure, and storage capacity of a 40 L flat-panel adsorbed NG tank filled with 20 kg of nanoporous carbon will be featured.

  18. High-density digital recording

    NASA Technical Reports Server (NTRS)

    Kalil, F. (Editor); Buschman, A. (Editor)

    1985-01-01

    The problems associated with high-density digital recording (HDDR) are discussed. Five independent users of HDDR systems and their problems, solutions, and insights are provided as guidance for other users of HDDR systems. Various pulse code modulation coding techniques are reviewed. An introduction to error detection and correction head optimization theory and perpendicular recording are provided. Competitive tape recorder manufacturers apply all of the above theories and techniques and present their offerings. The methodology used by the HDDR Users Subcommittee of THIC to evaluate parallel HDDR systems is presented.

  19. Preparation of hydroxylated polyethylene surfaces.

    PubMed

    Zand, A; Walter, N; Bahu, M; Ketterer, S; Sanders, M; Sikorski, Y; Cunningham, R; Beholz, L

    2008-01-01

    The surfaces of high-density or ultra-high-molecular-weight polyethylenes were hydroxylated using a two-step process. The wetting and wear properties of the untreated (virgin) and surface hydroxylated polyethylenes were compared. The introduction of hydroxyl groups provided an increase in surface hydrophilicity resulting in reduced wear. Hydrophilicity was analyzed by optical analysis of water contact angle. Wear was determined by weight loss under conditions of a reciprocating pin-on-plate apparatus with the panels immersed in water or calf serum. These results suggest that hydroxylation of polyethylene friction-bearing orthopedic surfaces may lead to a longer joint life. PMID:18318959

  20. High density harp for SSCL linac

    SciTech Connect

    Fritsche, C.T.; Krogh, M.L.; Crist, C.E.

    1993-05-01

    AlliedSignal Inc., Kansas City Division, and the Superconducting Super Collider Laboratory (SSCL) are collaboratively developing a high density harp for the SSCL linac. This harp is designed using hybrid microcircuit (HMC) technology to obtain a higher wire density than previously available. The developed harp contains one hundred twenty-eight 33-micron-diameter carbon wires on 0.38-mm centers. The harp features an onboard broken wire detection circuit. Carbon wire preparation and attachment processes were developed. High density surface mount connectors were located. The status of high density harp development will be presented along with planned future activities.

  1. Rheological properties of polyolefin composites highly filled with calcium carbonate

    NASA Astrophysics Data System (ADS)

    Nobile, Maria Rossella; Fierro, Annalisa; Jakubowska, Paulina; Sterzynski, Tomasz

    2016-05-01

    In this paper the rheological properties of highly filled polyolefin composites (HFPCs) have been investigated. Calcium carbonate (CaCO3), with stearic acid modified surface, was used as filler. Ternary compounds have been obtained by the inclusion of a CaCO3/polypropylene master batch into the high density polyethylene matrix. The highly filled polyolefin composites with CaCO3 content in the range between 40 and 64 wt% have been prepared in the molten state using a single-screw extruder, the temperature of the extrusion die was set at 230°C. The melt rheological properties of the HFPCs have been extensively investigated both in oscillatory and steady shear flow.

  2. High Density Fuel Development for Research Reactors

    SciTech Connect

    Daniel Wachs; Dennis Keiser; Mitchell Meyer; Douglas Burkes; Curtis Clark; Glenn Moore; Jan-Fong Jue; Totju Totev; Gerard Hofman; Tom Wiencek; Yeon So Kim; Jim Snelgrove

    2007-09-01

    An international effort to develop, qualify, and license high and very high density fuels has been underway for several years within the framework of multi-national RERTR programs. The current development status is the result of significant contributions from many laboratories, specifically CNEA in Argentina, AECL in Canada, CEA in France, TUM in Germany, KAERI in Korea, VNIIM, RDIPE, IPPE, NCCP and RIARR in Russia, INL, ANL and Y-12 in USA. These programs are mainly engaged with UMo dispersion fuels with densities from 6 to 8 gU/cm3 (high density fuel) and UMo monolithic fuel with density as high as 16 gU/cm3 (very high density fuel). This paper, mainly focused on the French & US programs, gives the status of high density UMo fuel development and perspectives on their qualification.

  3. High density load bearing insulation peg

    DOEpatents

    Nowobilski, J.J.; Owens, W.J.

    1985-01-29

    A high density peg is disclosed which can support a large load and exhibits excellent thermal resistance produced by a method wherein the peg is made in compliance with specified conditions of time, temperature and pressure. 4 figs.

  4. High density load bearing insulation peg

    DOEpatents

    Nowobilski, Jeffert J.; Owens, William J.

    1985-01-01

    A high density peg which can support a large load and exhibits excellent thermal resistance produced by a method wherein the peg is made in compliance with specified conditions of time, temperature and pressure.

  5. Profiles in garbage: Polyethylene terephthalate

    SciTech Connect

    Miller, C.

    1997-11-01

    Polyethylene terephthalate (PET) is a plastic resin used primarily to make bottles. Soft drinks -- along with salad dressing, fruit juices, peanut butter, and other household and consumer products -- use PET bottles. PET also is used for film, sheeting for cups and food trays, oven-safe trays, and other uses. PET is a relatively new packaging resin, first commercialized in the early 1970s. Because it is an ``engineered`` resin, PET is more expensive than commodity resins such as high-density polyethylene (HDPE) and, for the same reason, it is usually the highest valued plastic recyclable.

  6. Reliability of PWB Microvias for High Density Package Assembly

    NASA Technical Reports Server (NTRS)

    Ghaffarian, Reza

    2008-01-01

    High density PWB (printed wiring board) with microvia technology is required for implementation of high density and high I/O area array packages (AAP). COTS (commercial off-the-shelf) AAP packaging technologies in high reliability versions with 1.27 mm pitch are now being considered for use in a number of NASA systems including Space Shuttle and Mars Rovers. NASA functional system designs are requiring more and more dense AAP packages and board space, which makes board microvia technology very attractive for effectively routing a large number of package inputs/outputs. However, the reliability of the fine feature microvias including via in pads is unknown for space applications. Understanding process and QA (quality assurance) indicators for reliability are important for low risk insertion of these newly available packages and PWBs. This paper presents literature search as well as test results for a high density board subjected to various thermal cycle and reflow profiles representative of tin-lead and lead-free solder reflow. Microvias sizes ranged from two to six mil with and without filling. Daisy chain microvias monitored during the test and PWBs were cross-sectioned to determine failure and locations. Optical and SEM photographs as well as resistance changes during cycling and Tg/Td (glass transition/decomposition temperature) characterisations are presented.

  7. High Density Digital Data Storage System

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth D., II; Gray, David L.; Rowland, Wayne D.

    1991-01-01

    The High Density Digital Data Storage System was designed to provide a cost effective means for storing real-time data from the field-deployable digital acoustic measurement system. However, the high density data storage system is a standalone system that could provide a storage solution for many other real time data acquisition applications. The storage system has inputs for up to 20 channels of 16-bit digital data. The high density tape recorders presently being used in the storage system are capable of storing over 5 gigabytes of data at overall transfer rates of 500 kilobytes per second. However, through the use of data compression techniques the system storage capacity and transfer rate can be doubled. Two tape recorders have been incorporated into the storage system to produce a backup tape of data in real-time. An analog output is provided for each data channel as a means of monitoring the data as it is being recorded.

  8. Aerodynamic Focusing Of High-Density Aerosols

    SciTech Connect

    Ruiz, D. E.; Fisch, Nathaniel

    2014-02-24

    High-density micron-sized particle aerosols might form the basis for a number of applications in which a material target with a particular shape might be quickly ionized to form a cylindrical or sheet shaped plasma. A simple experimental device was built in order to study the properties of high-density aerosol focusing for 1 m silica spheres. Preliminary results recover previous findings on aerodynamic focusing at low densities. At higher densities, it is demonstrated that the focusing properties change in a way which is consistent with a density dependent Stokes number.

  9. TECHNICAL GUIDANCE DOCUMENT: THE FABRICATION OF POLYETHYLENE FML FIELD SEAMS

    EPA Science Inventory

    This technical guidance document is meant to augment the numerous construction quality control and construction assurance (CQC and CQA) guidelines that are presently available for high density polyethylene (HDPE) liner installation and inspection.

  10. High density carbon dispersion fuels program

    NASA Technical Reports Server (NTRS)

    Salvesen, R. H.; Lavid, M.

    1980-01-01

    High density carbon dispersion fuels were studied. Promising results were obtained which indicate stable carbon loaded fuels with a minimum of 180,000 Btu per gallon can be made and successfully burned in prototype turbine combustors components. Tests were completed which provide insights to obtaining a better understanding of what types of carbon can be successfully formulated and combusted.

  11. Supernovae and high density nuclear matter

    SciTech Connect

    Kahana, S.

    1986-01-01

    The role of the nuclear equation of state (EOS) in producing prompt supernova explosions is examined. Results of calculations of Baron, Cooperstein, and Kahana incorporating general relativity and a new high density EOS are presented, and the relevance of these calculations to laboratory experiments with heavy ions considered. 31 refs., 6 figs., 2 tabs.

  12. High Density Diffusion-Free Nanowell Arrays

    PubMed Central

    Takulapalli, Bharath R; Qiu, Ji; Magee, D. Mitchell; Kahn, Peter; Brunner, Al; Barker, Kristi; Means, Steven; Miersch, Shane; Bian, Xiaofang; Mendoza, Alex; Festa, Fernanda; Syal, Karan; Park, Jin; LaBaer, Joshua; Wiktor, Peter

    2012-01-01

    Proteomics aspires to elucidate the functions of all proteins. Protein microarrays provide an important step by enabling high-throughput studies of displayed proteins. However, many functional assays of proteins include untethered intermediates or products, which could frustrate the use of planar arrays at very high densities because of diffusion to neighboring features. The nucleic acid programmable protein array (NAPPA), is a robust, in situ synthesis method for producing functional proteins just-in-time, which includes steps with diffusible intermediates. We determined that diffusion of expressed proteins led to cross-binding at neighboring spots at very high densities with reduced inter-spot spacing. To address this limitation, we have developed an innovative platform using photolithographically-etched discrete silicon nanowells and used NAPPA as a test case. This arrested protein diffusion and cross-binding. We present confined high density protein expression and display, as well as functional protein-protein interactions, in 8,000 nanowell arrays. This is the highest density of individual proteins in nano-vessels demonstrated on a single slide. We further present proof of principle results on ultra-high density protein arrays capable of up to 24,000 nanowells on a single slide. PMID:22742968

  13. A model for the filling of cold cavities with solidifying, semi-crystalline polymers

    SciTech Connect

    Papathanasiou, T D; Guell, D C

    1992-01-01

    A model for the filling stage of injection molding that includes wall solidification and crystallisation was used to investigate the interaction between solidification and pressure drop during the filling of a rectangular plate with high-density polyethylene. We find that wall solidification affects the pressure drop in a complex way, reflecting the interplay between reduction in the area available for flow and thermal insulation of the still-molten polymer. Development of crystallinity on the surface of the part is also modelled under conditions of uniform and spatially varying cooling. Results indicate that nonuniform cooling can results in complex crystallinity distributions which are determined by thermal history of solidified polymer, duration of filling stage and by exact dependence of crystallisation kinetics on temperature.

  14. The high density Z-pinch

    NASA Astrophysics Data System (ADS)

    McCall, G. H.

    During the past few years techniques have been developed for producing pinches in solid deuterium. The conditions which exist in these plasmas are different from those produced earlier. The pinch is formed from a fiber of solid deuterium rather than from a low density gas, and the current is driven by a low impedance, high voltage pulse generator. Because of the high initial density, it is not necessary to compress the pinch to reach thermonuclear conditions, and the confinement time required for energy production is much shorter than for a gas. Results, which have been verified by experiments performed at higher current were quite surprising and encouraging. The pinch appeared to be stable for a time much longer than the Alfven radial transit time. It is argued that the pinch is not strictly stable, but it does not appear to disassemble in a catastrophic fashion. It appears that there may be a distinction between stability and confinement in the high density pinch. In the discussion below the status of the high density Z-pinch experiments at laboratories around the world is presented, and some of the calculational and experimental results described. Remarks are confined to recent work on the high density pinch.

  15. High density diffusion-free nanowell arrays.

    PubMed

    Takulapalli, Bharath R; Qiu, Ji; Magee, D Mitchell; Kahn, Peter; Brunner, Al; Barker, Kristi; Means, Steven; Miersch, Shane; Bian, Xiaofang; Mendoza, Alex; Festa, Fernanda; Syal, Karan; Park, Jin G; LaBaer, Joshua; Wiktor, Peter

    2012-08-01

    Proteomics aspires to elucidate the functions of all proteins. Protein microarrays provide an important step by enabling high-throughput studies of displayed proteins. However, many functional assays of proteins include untethered intermediates or products, which could frustrate the use of planar arrays at very high densities because of diffusion to neighboring features. The nucleic acid programmable protein array (NAPPA) is a robust in situ synthesis method for producing functional proteins just-in-time, which includes steps with diffusible intermediates. We determined that diffusion of expressed proteins led to cross-binding at neighboring spots at very high densities with reduced interspot spacing. To address this limitation, we have developed an innovative platform using photolithographically etched discrete silicon nanowells and used NAPPA as a test case. This arrested protein diffusion and cross-binding. We present confined high density protein expression and display, as well as functional protein-protein interactions, in 8000 nanowell arrays. This is the highest density of individual proteins in nanovessels demonstrated on a single slide. We further present proof of principle results on ultrahigh density protein arrays capable of up to 24000 nanowells on a single slide. PMID:22742968

  16. SECURING CONTAINERIZED HAZARDOUS WASTES WITH POLYETHYLENE RESIN AND FIBERGLASS ENCAPSULATES

    EPA Science Inventory

    This study investigates the fabrication and use of polyethylene resin and fiberglass to encapsulate and secure containerized hazardous wastes. Laboratory-scale encapsulates of composite structure were made from powdered, high-density polyethylene (HDPE) and epoxy-resin-wetted fib...

  17. The yield behavior of polyethylene tubes subjected to biaxial loadings

    NASA Technical Reports Server (NTRS)

    Semeliss, M.; Wong, R.; Tuttle, M.

    1990-01-01

    High-density polyethylene is subjected to biaxial states of stress to examine the yield behavior of the semicrystalline thermoplastic under constant octahedral shear-stress rates. Combinations of internal pressures and axial loads are applied to thin-walled tubes of polyethylene, and the strain response in the axial and hoop directions are measured. The polyethylene specimens are found to be anisotropic, and the experimental measurements are compared to yield criteria that are applicable to isotropic and anisotropic materials.

  18. Study On Temperature Distribution In T Fittings - Polyethylene Natural Gas Pipes Assemblies

    NASA Astrophysics Data System (ADS)

    Avrigean, Eugen

    2015-09-01

    The present paper intends to approach theoretically and experimentally an important topic concerning the operational safety of the polyethylene pipes used in natural gas distribution. We discuss the influence of temperature in the high density polyethylene elbows during welding to the polyethylene pipes.

  19. STRESS CRACK TESTING OF POLYETHYLENE GEOMEMBRANES

    EPA Science Inventory

    The sensitivity of high density polyethylene (HDPE) geomembranes to stress cracking is evaluated under accelerated conditions at a constant stress. he test specimens are according to ASTM D-1822, and are of the dumbbell shape with a constant length in the central section. he acce...

  20. High-Density Digital Data Storage System

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth D.; Gray, David L.

    1995-01-01

    High-density digital data storage system designed for cost-effective storage of large amounts of information acquired during experiments. System accepts up to 20 channels of 16-bit digital data with overall transfer rates of 500 kilobytes per second. Data recorded on 8-millimeter magnetic tape in cartridges, each capable of holding up to five gigabytes of data. Each cartridge mounted on one of two tape drives. Operator chooses to use either or both of drives. One drive used for primary storage of data while other can be used to make a duplicate record of data. Alternatively, other drive serves as backup data-storage drive when primary one fails.

  1. Two-color QCD at high density

    NASA Astrophysics Data System (ADS)

    Boz, Tamer; Giudice, Pietro; Hands, Simon; Skullerud, Jon-Ivar; Williams, Anthony G.

    2016-01-01

    QCD at high chemical potential has interesting properties such as deconfinement of quarks. Two-color QCD, which enables numerical simulations on the lattice, constitutes a laboratory to study QCD at high chemical potential. Among the interesting properties of two-color QCD at high density is the diquark condensation, for which we present recent results obtained on a finer lattice compared to previous studies. The quark propagator in two-color QCD at non-zero chemical potential is referred to as the Gor'kov propagator. We express the Gor'kov propagator in terms of form factors and present recent lattice simulation results.

  2. Regulation of high density lipoprotein levels

    SciTech Connect

    Krauss, R.M.

    1982-03-01

    An increasing awareness of the physiologic and pathologic importance of serum high density lipoproteins (HDL) has led to a large number of observations regarding factors which influence their concentrations. HDL consists of a heterogeneous collection of macromolecules with diverse physical properties and chemical constituents. While laboratory techniques have made it possible to measure HDL and their individual components, there are as yet large gaps in our knowledge of the biochemical mechanisms and clinical significance of changes in these laboratory parameters. In this review, current concepts of the structure and metabolism of HDL will be briefly summarized, and the factors influencing their levels in humans will be surveyed. 313 references.

  3. Method of high-density foil fabrication

    DOEpatents

    Blue, Craig A.; Sikka, Vinod K.; Ohriner, Evan K.

    2003-12-16

    A method for preparing flat foils having a high density includes the steps of mixing a powdered material with a binder to form a green sheet. The green sheet is exposed to a high intensity radiative source adapted to emit radiation of wavelengths corresponding to an absorption spectrum of the powdered material. The surface of the green sheet is heated while a lower sub-surface temperature is maintained. An apparatus for preparing a foil from a green sheet using a radiation source is also disclosed.

  4. High density circuit technology, part 1

    NASA Technical Reports Server (NTRS)

    Wade, T. E.

    1982-01-01

    The metal (or dielectric) lift-off processes used in the semiconductor industry to fabricate high density very large scale integration (VLSI) systems were reviewed. The lift-off process consists of depositing the light-sensitive material onto the wafer and patterning first in such a manner as to form a stencil for the interconnection material. Then the interconnection layer is deposited and unwanted areas are lifted off by removing the underlying stencil. Several of these lift-off techniques were examined experimentally. The use of an auxiliary layer of polyimide to form a lift-off stencil offers considerable promise.

  5. Some novel phenomena at high density

    NASA Astrophysics Data System (ADS)

    Berkowitz, Evan Scott

    Astrophysical environments probe matter in ways impossible on Earth. In particular, matter in compact objects are extraordinarily dense. In this thesis we discuss two phenomena that may occur at high density. First, we study toroidal topological solitons called vortons, which can occur in the kaon-condensed color-flavor-locked phase of high-density quark matter, a candidate phase for the core of some neutron stars. We show that vortons have a large radius compared to their thickness if their electrical charge is on the order of 104 times the fundamental charge. We show that shielding of electric fields by electrons dramatically reduces the size of a vorton. Second, we study an unusual phase of degenerate electrons and nonrelativistic Bose-condensed helium nuclei that may exist in helium white dwarfs. We show that this phase supports a previously-unknown gapless mode, known as the half-sound, that radically alters the material's specific heat, and can annihilate into neutrinos. We provide evidence that this neutrino radiation is negligible compared to the star's surface photoemission.

  6. Cortical high-density counterstream architectures.

    PubMed

    Markov, Nikola T; Ercsey-Ravasz, Mária; Van Essen, David C; Knoblauch, Kenneth; Toroczkai, Zoltán; Kennedy, Henry

    2013-11-01

    Small-world networks provide an appealing description of cortical architecture owing to their capacity for integration and segregation combined with an economy of connectivity. Previous reports of low-density interareal graphs and apparent small-world properties are challenged by data that reveal high-density cortical graphs in which economy of connections is achieved by weight heterogeneity and distance-weight correlations. These properties define a model that predicts many binary and weighted features of the cortical network including a core-periphery, a typical feature of self-organizing information processing systems. Feedback and feedforward pathways between areas exhibit a dual counterstream organization, and their integration into local circuits constrains cortical computation. Here, we propose a bow-tie representation of interareal architecture derived from the hierarchical laminar weights of pathways between the high-efficiency dense core and periphery. PMID:24179228

  7. Ground state of high-density matter

    NASA Technical Reports Server (NTRS)

    Copeland, ED; Kolb, Edward W.; Lee, Kimyeong

    1988-01-01

    It is shown that if an upper bound to the false vacuum energy of the electroweak Higgs potential is satisfied, the true ground state of high-density matter is not nuclear matter, or even strange-quark matter, but rather a non-topological soliton where the electroweak symmetry is exact and the fermions are massless. This possibility is examined in the standard SU(3) sub C tensor product SU(2) sub L tensor product U(1) sub Y model. The bound to the false vacuum energy is satisfied only for a narrow range of the Higgs boson masses in the minimal electroweak model (within about 10 eV of its minimum allowed value of 6.6 GeV) and a somewhat wider range for electroweak models with a non-minimal Higgs sector.

  8. Fluid hydrogen at high density - Pressure dissociation

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1991-01-01

    A model for the Helmholtz free energy of fluid hydrogen at high density and high temperature is developed. This model aims at describing both pressure and temperature dissociation and ionization and bears directly on equations of state of partially ionized plasmas, as encountered in astrophysical situations and high-pressure experiments. This paper focuses on a mixture of hydrogen atoms and molecules and is devoted to the study of the phenomenon of pressure dissociation at finite temperatures. In the present model, the strong interactions are described with realistic potentials and are computed with a modified Weeks-Chandler-Andersen fluid perturbation theory that reproduces Monte Carlo simulations to better than 3 percent. Theoretical Hugoniot curves derived from the model are in excellent agreement with experimental data.

  9. Ultra-high density diffraction grating

    DOEpatents

    Padmore, Howard A.; Voronov, Dmytro L.; Cambie, Rossana; Yashchuk, Valeriy V.; Gullikson, Eric M.

    2012-12-11

    A diffraction grating structure having ultra-high density of grooves comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The surface of the diffraction grating is planarized, such that layers of the multi-layer stack form a plurality of lines disposed on the planarized surface of the structure in a periodical fashion, wherein lines having a first property alternate with lines having a dissimilar property on the surface of the substrate. For example, in one embodiment, lines comprising high-Z and low-Z materials alternate on the planarized surface providing a structure that is suitable as a diffraction grating for EUV and soft X-rays. In some embodiments, line density of between about 10,000 lines/mm to about 100,000 lines/mm is provided.

  10. High-Density, Scintillating, Fluoride Glass Calorimeters

    NASA Astrophysics Data System (ADS)

    Akgun, Ugur; Xie, Qiuchen

    2014-03-01

    The unprecedented radiation levels in current Large Hadron Collider runs, and plans to even increase the luminosity creates a need for new detector technologies to be investigated. Here, we propose to use high density, scintillating, fluoride glasses as active media in calorimeters. CHG3 is a special example of this glass family, which has been developed specifically for hadron collider experiments, and is known for fast response time, in addition to high light yield. In this presentation, the results from a computational study on the performances of the two different designs of CHG3 glass calorimeters are reported. First design reads the signal directly from the edge of the glass plate; the second design utilizes wavelength-shifting fibers to carry the signal out of the glass plate. Each simulation model is a sampling calorimeter with 20 alternating layers of glass and iron absorber. By changing the absorber thickness we tested hadronic as well as electromagnetic capabilities of the calorimeter models.

  11. Manufacture of high-density ceramic sinters

    NASA Technical Reports Server (NTRS)

    Hibata, Y.

    1986-01-01

    High density ceramic sinters are manufactured by coating premolded or presintered porous ceramics with a sealing material of high SiO2 porous glass or nitride glass and then sintering by hot isostatic pressing. The ceramics have excellent abrasion and corrosion resistances. Thus LC-10 (Si3N2 powder) and Y2O3-Al2O3 type sintering were mixed and molded to give a premolded porous ceramic (porosity 37%, relative bulk density 63%). The ceramic was dipped in a slurry containing high SiO2 porous glass and an alcohol solution of cellulose acetate and dried. The coated ceramic was treated in a nitrogen atmosphere and then sintered by hot isostatic pressing to give a dense ceramic sinter.

  12. High-density fiber optic biosensor arrays

    NASA Astrophysics Data System (ADS)

    Epstein, Jason R.; Walt, David R.

    2002-02-01

    Novel approaches are required to coordinate the immense amounts of information derived from diverse genomes. This concept has influenced the expanded role of high-throughput DNA detection and analysis in the biological sciences. A high-density fiber optic DNA biosensor was developed consisting of oligonucleotide-functionalized, 3.1 mm diameter microspheres deposited into the etched wells on the distal face of a 500 micrometers imaging fiber bundle. Imaging fiber bundles containing thousands of optical fibers, each associated with a unique oligonucleotide probe sequence, were the foundation for an optically connected, individually addressable DNA detection platform. Different oligonucleotide-functionalized microspheres were combined in a stock solution, and randomly dispersed into the etched wells. Microsphere positions were registered from optical dyes incorporated onto the microspheres. The distribution process provided an inherent redundancy that increases the signal-to-noise ratio as the square root of the number of sensors examined. The representative amount of each probe-type in the array was dependent on their initial stock solution concentration, and as other sequences of interest arise, new microsphere elements can be added to arrays without altering the existing detection capabilities. The oligonucleotide probe sequences hybridize to fluorescently-labeled, complementary DNA target solutions. Fiber optic DNA microarray research has included DNA-protein interaction profiles, microbial strain differentiation, non-labeled target interrogation with molecular beacons, and single cell-based assays. This biosensor array is proficient in DNA detection linked to specific disease states, single nucleotide polymorphism (SNP's) discrimination, and gene expression analysis. This array platform permits multiple detection formats, provides smaller feature sizes, and enables sensor design flexibility. High-density fiber optic microarray biosensors provide a fast

  13. High density plasma etching of magnetic devices

    NASA Astrophysics Data System (ADS)

    Jung, Kee Bum

    Magnetic materials such as NiFe (permalloy) or NiFeCo are widely used in the data storage industry. Techniques for submicron patterning are required to develop next generation magnetic devices. The relative chemical inertness of most magnetic materials means they are hard to etch using conventional RIE (Reactive Ion Etching). Therefore ion milling has generally been used across the industry, but this has limitations for magnetic structures with submicron dimensions. In this dissertation, we suggest high density plasmas such as ECR (Electron Cyclotron Resonance) and ICP (Inductively Coupled Plasma) for the etching of magnetic materials (NiFe, NiFeCo, CoFeB, CoSm, CoZr) and other related materials (TaN, CrSi, FeMn), which are employed for magnetic devices like magnetoresistive random access memories (MRAM), magnetic read/write heads, magnetic sensors and microactuators. This research examined the fundamental etch mechanisms occurring in high density plasma processing of magnetic materials by measuring etch rate, surface morphology and surface stoichiometry. However, one concern with using Cl2-based plasma chemistry is the effect of residual chlorine or chlorinated etch residues remaining on the sidewalls of etched features, leading to a degradation of the magnetic properties. To avoid this problem, we employed two different processing methods. The first one is applying several different cleaning procedures, including de-ionized water rinsing or in-situ exposure to H2, O2 or SF6 plasmas. Very stable magnetic properties were achieved over a period of ˜6 months except O2 plasma treated structures, with no evidence of corrosion, provided chlorinated etch residues were removed by post-etch cleaning. The second method is using non-corrosive gas chemistries such as CO/NH3 or CO2/NH3. There is a small chemical contribution to the etch mechanism (i.e. formation of metal carbonyls) as determined by a comparison with Ar and N2 physical sputtering. The discharge should be NH3

  14. Waste product profile: Polyethylene terephthalate

    SciTech Connect

    Miller, C.

    1996-02-01

    Polyethylene terephthalate (PET) is a plastic resin used primarily to make bottles. Soft drinks are the primary product packaged in PET. Salad dressing, peanut butter, and other household and consumer products also use PET bottles. PET is also used for film, sheeting for cups and food trays, ovenable trays, and other uses. PET is a relatively new packaging resin, first commercialized in the early `70s. Because it is an ``engineered`` resin, it is more expensive than commodity resins such as high-density polyethylene (HDPE). The primary market for recycled PET is the fiber industry, which uses PET for carpet fiber, sweaters and other clothing, and for other uses. Recycled PET can also be used for food and beverage containers. Export markets, particularly Asian countries, are becoming increasingly important.

  15. Abnormal high density lipoproteins in cerebrotendinous xanthomatosis

    SciTech Connect

    Shore, V.; Salen, G.; Cheng, F.W.; Forte, T.; Shefer, S.; Tint, G.S.

    1981-11-01

    The plasma lipoprotein profiles and high density lipoproteins (HDL) were characterized in patients with the genetic disease cerebrotendinous xanthomatosis (CTX). The mean HDL-cholesterol concentration in the CTX plasmas was 14.5 +/- 3.2 mg/dl, about one-third the normal value. The low HDL-cholesterol reflects a low concentration and an abnormal lipid composition of the plasma HDL. Relative to normal HDL, the cholesteryl esters are low, free cholesterol and phospholipids essentially normal, and triglycerides increased. The ratio of apoprotein (apo) to total cholesterol in the HDL of CTX was two to three times greater than normal. In the CTX HDL, the ratio of apoAI to apoAII was high, the proportion of apoC low, and a normally minor form of apoAI increased relative to other forms. The HDL in electron micrographs appeared normal morphologically and in particle size. The adnormalities in lipoprotein distribution profiles and composition of the plasma HDL result from metabolic defects that are not understood but may be linked to the genetic defect in bile acid synthesis in CTX. As a consequence, it is probable that the normal functions of the HDL, possibly including modulation of LDL-cholesterol uptake and the removal of excess cholesterol from peripheral tissues, are perturbed significantly in this disease.

  16. Dark High Density Dipolar Liquid of Excitons.

    PubMed

    Cohen, Kobi; Shilo, Yehiel; West, Ken; Pfeiffer, Loren; Rapaport, Ronen

    2016-06-01

    The possible phases and the nanoscale particle correlations of two-dimensional interacting dipolar particles is a long-sought problem in many-body physics. Here we observe a spontaneous condensation of trapped two-dimensional dipolar excitons with internal spin degrees of freedom from an interacting gas into a high density, closely packed liquid state made mostly of dark dipoles. Another phase transition, into a bright, highly repulsive plasma, is observed at even higher excitation powers. The dark liquid state is formed below a critical temperature Tc ≈ 4.8 K, and it is manifested by a clear spontaneous spatial condensation to a smaller and denser cloud, suggesting an attractive part to the interaction which goes beyond the purely repulsive dipole-dipole forces. Contributions from quantum mechanical fluctuations are expected to be significant in this strongly correlated, long living dark liquid. This is a new example of a two-dimensional atomic-like interacting dipolar liquid, but where the coupling of light to its internal spin degrees of freedom plays a crucial role in the dynamical formation and the nature of resulting condensed dark ground state. PMID:27183418

  17. Regulation of high-density lipoprotein metabolism.

    PubMed

    Rye, Kerry-Anne; Barter, Philip J

    2014-01-01

    There is compelling evidence from human population studies that plasma levels of high-density lipoprotein (HDL) cholesterol correlate inversely with cardiovascular risk. Identification of this relationship has stimulated research designed to understand how HDL metabolism is regulated. The ultimate goal of these studies has been to develop HDL-raising therapies that have the potential to decrease the morbidity and mortality associated with atherosclerotic cardiovascular disease. However, the situation has turned out to be much more complex than originally envisaged. This is partly because the HDL fraction consists of multiple subpopulations of particles that vary in terms of shape, size, composition, and surface charge, as well as in their potential cardioprotective properties. This heterogeneity is a consequence of the continual remodeling and interconversion of HDL subpopulations by multiple plasma factors. Evidence that the remodeling of HDLs may impact on their cardioprotective properties is beginning to emerge. This serves to highlight the importance of understanding not only how the remodeling and interconversion of HDL subpopulations is regulated but also how these processes are affected by agents that increase HDL levels. This review provides an overview of what is currently understood about HDL metabolism and how the subpopulation distribution of these lipoproteins is regulated. PMID:24385508

  18. High-density electroencephalography developmental neurophysiological trajectories.

    PubMed

    Dan, Bernard; Pelc, Karine; Cebolla, Ana M; Cheron, Guy

    2015-04-01

    Efforts to document early changes in the developing brain have resulted in the construction of increasingly accurate structural images based on magnetic resonance imaging (MRI) in newborn infants. Tractography diagrams obtained through diffusion tensor imaging have focused on white matter microstructure, with particular emphasis on neuronal connectivity at the level of fibre tract systems. Electroencephalography (EEG) provides a complementary approach with more direct access to brain electrical activity. Its temporal resolution is excellent, and its spatial resolution can be enhanced to physiologically relevant levels, through the combination of high-density recordings (e.g. by using 64 channels in newborn infants) and mathematical models (e.g. inverse modelling computation), to identify generators of different oscillation bands and synchrony patterns. The integration of functional and structural topography of the neonatal brain provides insights into typical brain organization, and the deviations seen in particular contexts, for example the effect of hypoxic-ischaemic insult in terms of damage, eventual reorganization, and functional changes. Endophenotypes can then be used for pathophysiological reasoning, management planning, and outcome measurements, and allow a longitudinal approach to individual developmental trajectories. PMID:25800492

  19. Polyethylene Glycol 3350

    MedlinePlus

    Polyethylene glycol 3350 is used to treat occasional constipation. Polyethylene glycol 3350 is in a class of medications ... Polyethylene glycol 3350 comes as a powder to be mixed with a liquid and taken by mouth. ...

  20. 14 CFR 93.123 - High density traffic airports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false High density traffic airports. 93.123... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93.123 High density traffic airports. (a) Each of the following airports is designated as a...

  1. 14 CFR 93.123 - High density traffic airports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false High density traffic airports. 93.123... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93.123 High density traffic airports. (a) Each of the following airports is designated as a...

  2. 14 CFR 93.123 - High density traffic airports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false High density traffic airports. 93.123... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93.123 High density traffic airports. (a) Each of the following airports is designated as a...

  3. 14 CFR 93.123 - High density traffic airports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false High density traffic airports. 93.123... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93.123 High density traffic airports. (a) Each of the following airports is designated as a...

  4. 14 CFR 93.123 - High density traffic airports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false High density traffic airports. 93.123... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93.123 High density traffic airports. (a) Each of the following airports is designated as a...

  5. Natural fibre high-density polyethylene and lead oxide composites for radiation shielding

    NASA Astrophysics Data System (ADS)

    El-Sayed Abdo, A.; Ali, M. A. M.; Ismail, M. R.

    2003-03-01

    Study has been made of the radiation shielding provided by recycled agricultural fibre and industrial plastic wastes produced as composite materials. Fast neutron and gamma-ray spectra behind composites of fibre-plastic ( ρ = 1.373 g cm -3) and fibre-plastic-lead ( ρ = 2.756 g cm -3) have been measured using a collimated reactor beam and neutron-gamma spectrometer with a stilbene scintillator. The pulse shape discriminating technique based on the zero-cross-over method was used to discriminate between neutron and gamma-ray pulses. Slow neutron fluxes have been measured using a collimated reactor beam and BF 3 counter, leading to determination of the macroscopic cross-section ( Σ). The removal cross-sections ( ΣR) of fast neutrons have been determined from measured results and elemental composition of the composites. For gamma-rays, total linear attenuation coefficients ( μ) and total mass attenuation coefficients ( μ/ ρ) have been determined from use of the XCOM code and measured results. Reasonable agreement was found between measured and calculated results.

  6. High-density plasma deposition manufacturing productivity improvement

    NASA Astrophysics Data System (ADS)

    Olmer, Leonard J.; Hudson, Chris P.

    1999-09-01

    High Density Plasma (HDP) deposition provides a means to deposit high quality dielectrics meeting submicron gap fill requirements. But, compared to traditional PECVD processing, HDP is relatively expensive due to the higher capital cost of the equipment. In order to keep processing costs low, it became necessary to maximize the wafer throughput of HDP processing without degrading the film properties. The approach taken was to optimize the post deposition microwave in-situ clean efficiency. A regression model, based on actual data, indicated that number of wafers processed before a chamber clean was the dominant factor. Furthermore, a design change in the ceramic hardware, surrounding the electrostatic chuck, provided thermal isolation resulting in an enhanced clean rate of the chamber process kit. An infra-red detector located in the chamber exhaust line provided a means to endpoint the clean and in-film particle data confirmed the infra-red results. The combination of increased chamber clean frequency, optimized clean time and improved process.

  7. Itinerary of high density lipoproteins in endothelial cells.

    PubMed

    Perisa, Damir; Rohrer, Lucia; Kaech, Andres; von Eckardstein, Arnold

    2016-02-01

    High density lipoprotein (HDL) and its main protein component apolipoprotein A-I (ApoA-I) have multiple anti-atherogenic functions. Some of them are exerted within the vessel wall, so that HDL needs to pass the endothelial barrier. To elucidate their itinerary through endothelial cells (ECs), we labelled ApoA-I and HDL either fluorescently or with 1.4 nm nanogold and investigated their cellular localization by using immunofluorescent microscopy (IFM) and electron microscopy (EM). HDL as well as ApoA-I is taken up by ECs into the same route of intracellular trafficking. Time kinetics and pulse chase experiments revealed that HDL is trafficked through different vesicles. HDL partially co-localized with LDL, albumin, and transferrin. HDL did not co-localize with clathrin and caveolin-1. Fluorescent HDL was recovered at small proportions in early endosomes and endosome to trans-golgi network vesicles but not at all in recycling endosomes, in late endosomes or lysosomes. EM identified HDL mainly in large filled vesicles which however upon IFM did not colocalize with markers of multivesicular bodies or autophagosomes. The uptake or cellular distribution of HDL was altered upon pharmacological interference with cytochalasine D, colchicine and dynasore. Blockage of fluid phase uptake with Amiloride or EIPA did not reduce the uptake of HDL. Neither did we observe any co-localization of HDL with dextran as the marker of fluid phase uptake. In conclusion, HDL and ApoA-I are internalized and trafficked by endothelial cells through a non-classical endocytic route. PMID:26577406

  8. Electric field directed assembly of high-density microbead arrays†

    PubMed Central

    Barbee, Kristopher D.; Hsiao, Alexander P.; Heller, Michael J.; Huang, Xiaohua

    2010-01-01

    We report a method for rapid, electric field directed assembly of high-density protein-conjugated microbead arrays. Photolithography is used to fabricate an array of micron to sub-micron-scale wells in an epoxy-based photoresist on a silicon wafer coated with a thin gold film, which serves as the primary electrode. A thin gasket is used to form a microfluidic chamber between the wafer and a glass coverslip coated with indium-tin oxide, which serves as the counter electrode. Streptavidin-conjugated microbeads suspended in a low conductance buffer are introduced into the chamber and directed into the wells via electrophoresis by applying a series of low voltage electrical pulses across the electrodes. Hundreds of millions of microbeads can be permanently assembled on these arrays in as little as 30 seconds and the process can be monitored in real time using epifluorescence microscopy. The binding of the microbeads to the gold film is robust and occurs through electrochemically induced gold-protein interactions, which allows excess beads to be washed away or recycled. The well and bead sizes are chosen such that only one bead can be captured in each well. Filling efficiencies greater than 99.9% have been demonstrated across wafer-scale arrays with densities as high as 69 million beads per cm2. Potential applications for this technology include the assembly of DNA arrays for high-throughput genome sequencing and antibody arrays for proteomic studies. Following array assembly, this device may also be used to enhance the concentration-dependent processes of various assays through the accelerated transport of molecules using electric fields. PMID:19865735

  9. Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water

    NASA Astrophysics Data System (ADS)

    Giovambattista, Nicolas; Stanley, H. Eugene; Sciortino, Francesco

    2005-03-01

    It has been suggested that high-density amorphous (HDA) ice is a structurally arrested form of high-density liquid (HDL) water, while low-density amorphous ice is a structurally arrested form of low-density liquid (LDL) water. Recent experiments and simulations have been interpreted to support the possibility of a second distinct high-density structural state, named very high-density amorphous (VHDA) ice, questioning the LDL-HDL hypothesis. We test this interpretation using extensive computer simulations and find that VHDA is a more stable form of HDA and that, in fact, VHDA should be considered as the amorphous ice of the quenched HDL.

  10. Phenomenology of high density disruptions in the TFTR tokamak

    SciTech Connect

    Fredrickson, E.D.; McGuire, K.; Bell, M.; Bush, C.E.; Cavallo, A.; Budny, R.; Janos, A.; Mansfield, D.; Nagayama, Y.; Park, H.; Schivell, J.; Taylor, G.; Zarnstorff, M.C. . Plasma Physics Lab.); Drake, J.; Kleva, R. )

    1992-01-01

    Recent studies on TFTR of high density disruptions have made significant advances in closing the gap between theoretical models of disruptions and the experimental data. For the first time, an (m,n) = (1,1) cold bubble'' precursor to the high density disruptions has been experimentally observed. The precursor resembles the vacuum bubble'' model of disruptions first proposed by Kadomtsev and Pogutse.

  11. Phenomenology of high density disruptions in the TFTR tokamak

    SciTech Connect

    Fredrickson, E.D.; McGuire, K.; Bell, M.; Bush, C.E.; Cavallo, A.; Budny, R.; Janos, A.; Mansfield, D.; Nagayama, Y.; Park, H.; Schivell, J.; Taylor, G.; Zarnstorff, M.C.; Drake, J.; Kleva, R.

    1992-01-01

    Recent studies on TFTR of high density disruptions have made significant advances in closing the gap between theoretical models of disruptions and the experimental data. For the first time, an (m,n) = (1,1) ``cold bubble`` precursor to the high density disruptions has been experimentally observed. The precursor resembles the ``vacuum bubble`` model of disruptions first proposed by Kadomtsev and Pogutse.

  12. Small-Scale Production of High-Density Dry Ice: A Variant Combination of Two Classic Demonstrations

    ERIC Educational Resources Information Center

    Flowers, Paul A.

    2009-01-01

    Easily recoverable, thumb-sized pieces of high-density dry ice are conveniently produced by deposition of carbon dioxide within a test tube submerged in liquid nitrogen. A carbon dioxide-filled balloon sealed over the mouth of the test tube serves as a gas reservoir, and further permits a dramatic demonstration of both the gas-to-solid phase…

  13. Superradiance of High Density Frenkel Excitons at Room Temperature

    NASA Astrophysics Data System (ADS)

    Wang, H. Z.; Zheng, X. G.; Zhao, F. L.; Gao, Z. L.; Yu, Z. X.

    1995-05-01

    Superradiance of high density Frenkel excitons in an R-phycoerythrin single crystal is observed at room temperature for the first time. No fluorescence is observed except the emission at the sharp exciton band when the superradiance of excitons occurs, and the higher the pump density, the sharper the emission bandwidth. A redshift and a blueshift are observed at the rise time and the fall time of the emission pulse, respectively. The experimental results also imply deformed-boson properties of high density Frenkel excitons.

  14. High density semiconductor nanodots by direct laser fabrication

    NASA Astrophysics Data System (ADS)

    Haghizadeh, Anahita; Yang, Haeyeon

    2016-03-01

    We report a direct method of fabricating high density nanodots on the GaAs(001) surfaces using laser irradiations on the surface. Surface images indicate that the large clumps are not accompanied with the formation of nanodots even though its density is higher than the critical density above which detrimental large clumps begin to show up in the conventional Stranski-Krastanov growth technique. Atomic force microscopy is used to image the GaAs(001) surfaces that are irradiated by high power laser pulses interferentially. The analysis suggests that high density quantum dots be fabricated directly on semiconductor surfaces.

  15. High-density carbon ablator experiments on the National Ignition Facility

    SciTech Connect

    MacKinnon, A. J. Meezan, N. B.; Ross, J. S.; Le Pape, S.; Berzak Hopkins, L.; Divol, L.; Ho, D.; Milovich, J.; Pak, A.; Ralph, J.; Döppner, T.; Patel, P. K.; Thomas, C.; Tommasini, R.; Haan, S.; MacPhee, A. G.; McNaney, J.; Caggiano, J.; Hatarik, R.; Bionta, R.; and others

    2014-05-15

    High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has a higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results in a thinner ablator with a larger inner radius for a given capsule scale. This leads to higher x-ray absorption and shorter laser pulses compared to equivalent CH designs. This paper will describe a series of experiments carried out to examine the feasibility of using HDC as an ablator using both gas filled hohlraums and lower density, near vacuum hohlraums. These experiments have shown that deuterium (DD) and deuterium-tritium gas filled HDC capsules driven by a hohlraum filled with 1.2 mg/cc He gas, produce neutron yields a factor of 2× higher than equivalent CH implosions, representing better than 50% Yield-over-Clean (YoC). In a near vacuum hohlraum (He = 0.03 mg/cc) with 98% laser-to-hohlraum coupling, such a DD gas-filled capsule performed near 1D expectations. A cryogenic layered implosion version was consistent with a fuel velocity = 410 ± 20 km/s with no observed ablator mixing into the hot spot.

  16. High-density carbon ablator experiments on the National Ignition Facilitya)

    NASA Astrophysics Data System (ADS)

    MacKinnon, A. J.; Meezan, N. B.; Ross, J. S.; Le Pape, S.; Berzak Hopkins, L.; Divol, L.; Ho, D.; Milovich, J.; Pak, A.; Ralph, J.; Döppner, T.; Patel, P. K.; Thomas, C.; Tommasini, R.; Haan, S.; MacPhee, A. G.; McNaney, J.; Caggiano, J.; Hatarik, R.; Bionta, R.; Ma, T.; Spears, B.; Rygg, J. R.; Benedetti, L. R.; Town, R. P. J.; Bradley, D. K.; Dewald, E. L.; Fittinghoff, D.; Jones, O. S.; Robey, H. R.; Moody, J. D.; Khan, S.; Callahan, D. A.; Hamza, A.; Biener, J.; Celliers, P. M.; Braun, D. G.; Erskine, D. J.; Prisbrey, S. T.; Wallace, R. J.; Kozioziemski, B.; Dylla-Spears, R.; Sater, J.; Collins, G.; Storm, E.; Hsing, W.; Landen, O.; Atherton, J. L.; Lindl, J. D.; Edwards, M. J.; Frenje, J. A.; Gatu-Johnson, M.; Li, C. K.; Petrasso, R.; Rinderknecht, H.; Rosenberg, M.; Séguin, F. H.; Zylstra, A.; Knauer, J. P.; Grim, G.; Guler, N.; Merrill, F.; Olson, R.; Kyrala, G. A.; Kilkenny, J. D.; Nikroo, A.; Moreno, K.; Hoover, D. E.; Wild, C.; Werner, E.

    2014-05-01

    High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has a higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results in a thinner ablator with a larger inner radius for a given capsule scale. This leads to higher x-ray absorption and shorter laser pulses compared to equivalent CH designs. This paper will describe a series of experiments carried out to examine the feasibility of using HDC as an ablator using both gas filled hohlraums and lower density, near vacuum hohlraums. These experiments have shown that deuterium (DD) and deuterium-tritium gas filled HDC capsules driven by a hohlraum filled with 1.2 mg/cc He gas, produce neutron yields a factor of 2× higher than equivalent CH implosions, representing better than 50% Yield-over-Clean (YoC). In a near vacuum hohlraum (He = 0.03 mg/cc) with 98% laser-to-hohlraum coupling, such a DD gas-filled capsule performed near 1D expectations. A cryogenic layered implosion version was consistent with a fuel velocity = 410 ± 20 km/s with no observed ablator mixing into the hot spot.

  17. High-density carbon ablator experiments on the National Ignition Facilitya)

    SciTech Connect

    MacKinnon, A. J.; Meezan, N. B.; Ross, J. S.; Le Pape, S.; Berzak Hopkins, L.; Divol, L.; Ho, D.; Milovich, J.; Pak, A.; Ralph, J.; Döppner, T.; Patel, P. K.; Thomas, C.; Tommasini, R.; Haan, S.; MacPhee, A. G.; McNaney, J.; Caggiano, J.; Hatarik, R.; Bionta, R.; Ma, T.; Spears, B.; Rygg, J. R.; Benedetti, L. R.; Town, R. P. J.; Bradley, D. K.; Dewald, E. L.; Fittinghoff, D.; Jones, O. S.; Robey, H. R.; Moody, J. D.; Khan, S.; Callahan, D. A.; Hamza, A.; Biener, J.; Celliers, P. M.; Braun, D. G.; Erskine, D. J.; Prisbrey, S. T.; Wallace, R. J.; Kozioziemski, B.; Dylla-Spears, R.; Sater, J.; Collins, G.; Storm, E.; Hsing, W.; Landen, O.; Atherton, J. L.; Lindl, J. D.; Edwards, M. J.; Frenje, J. A.; Gatu-Johnson, M.; Li, C. K.; Petrasso, R.; Rinderknecht, H.; Rosenberg, M.; Séguin, F. H.; Zylstra, A.; Knauer, J. P.; Grim, G.; Guler, N.; Merrill, F.; Olson, R.; Kyrala, G. A.; Kilkenny, J. D.; Nikroo, A.; Moreno, K.; Hoover, D. E.; Wild, C.; Werner, E.

    2014-05-01

    High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has a higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results in a thinner ablator with a larger inner radius for a given capsule scale. This leads to higher x-ray absorption and shorter laser pulses compared to equivalent CH designs. This paper will describe a series of experiments carried out to examine the feasibility of using HDC as an ablator using both gas filled hohlraums and lower density, near vacuum hohlraums. These experiments have shown that deuterium (DD) and deuterium-tritium gas filled HDC capsules driven by a hohlraum filled with 1.2 mg/cc He gas, produce neutron yields a factor of 2× higher than equivalent CH implosions, representing better than 50% Yield-over-Clean (YoC). In a near vacuum hohlraum (He = 0.03 mg/cc) with 98% laser-to-hohlraum coupling, such a DD gas-filled capsule performed near 1D expectations. A cryogenic layered implosion version was consistent with a fuel velocity = 410 ± 20 km/s with no observed ablator mixing into the hot spot.

  18. High density packaging and interconnect of massively parallel image processors

    NASA Technical Reports Server (NTRS)

    Carson, John C.; Indin, Ronald J.

    1991-01-01

    This paper presents conceptual designs for high density packaging of parallel processing systems. The systems fall into two categories: global memory systems where many processors are packaged into a stack, and distributed memory systems where a single processor and many memory chips are packaged into a stack. Thermal behavior and performance are discussed.

  19. High density constraint on the entropy instability. [with nonisothermal effect

    NASA Technical Reports Server (NTRS)

    Hudson, M. K.; Kennel, C. F.

    1974-01-01

    The entropy instability squared is a nonisothermal effect which is eliminated by parallel ion pressure at high densities (k sub z lambda sub e 1/2 sq root of m/M), reducing previous growth rate estimates and the range of unstable parameters.

  20. High Density Polymer-Based Integrated Electgrode Array

    DOEpatents

    Maghribi, Mariam N.; Krulevitch, Peter A.; Davidson, James Courtney; Hamilton, Julie K.

    2006-04-25

    A high density polymer-based integrated electrode apparatus that comprises a central electrode body and a multiplicity of arms extending from the electrode body. The central electrode body and the multiplicity of arms are comprised of a silicone material with metal features in said silicone material that comprise electronic circuits.

  1. A Novel Anti-Inflammatory Effect for High Density Lipoprotein

    PubMed Central

    Cameron, Scott J.; Morrell, Craig N.; Bao, Clare; Swaim, AnneMarie F.; Rodriguez, Annabelle; Lowenstein, Charles J.

    2015-01-01

    High density lipoprotein has anti-inflammatory effects in addition to mediating reverse cholesterol transport. While many of the chronic anti-inflammatory effects of high density lipoprotein (HDL) are attributed to changes in cell adhesion molecules, little is known about acute signal transduction events elicited by HDL in endothelial cells. We now show that high density lipoprotein decreases endothelial cell exocytosis, the first step in leukocyte trafficking. ApoA-I, a major apolipoprotein of HDL, mediates inhibition of endothelial cell exocytosis by interacting with endothelial scavenger receptor-BI which triggers an intracellular protective signaling cascade involving protein kinase C (PKC). Other apolipoproteins within the HDL particle have only modest effects upon endothelial exocytosis. Using a human primary culture of endothelial cells and murine apo-AI knockout mice, we show that apo-AI prevents endothelial cell exocytosis which limits leukocyte recruitment. These data suggest that high density lipoprotein may inhibit diseases associated with vascular inflammation in part by blocking endothelial exocytosis. PMID:26680360

  2. Genomic imputation and evaluation using 342 high density Holstein genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic evaluations for 73,749 Holsteins were computed using 636,967 of the 777,000 markers on the Illumina high density (HD) chip. Observed data included 342 animals with HD genotypes, 54,676 animals with 42,503 marker (50K) genotypes, 17,371 animals with 2,614 marker (3K) genotypes, and 1,360 nong...

  3. Genomic imputation and evaluation using high density Holstein genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic evaluations for 161,341 Holsteins were computed using 311,725 of the 777,962 markers on the Illumina high-density (HD) chip. Initial edits with 1,741 HD genotypes from 5 breeds revealed that 636,967 markers were usable but that half were redundant. Usable Holstein genotypes included 1,510 an...

  4. High-density, homogeneous endospore monolayer deposition on test surfaces.

    PubMed

    Noell, Aaron C; Greenwood, Arin R; Lee, Christine M; Ponce, Adrian

    2013-09-01

    Bacillus subtilis spores were deposited in high-density single layers on metal, glass, and polymer substrates using vacuum filtration followed by a wetted filter transfer step. Quantitative analysis of spore transfer was performed using culture-based and germinability assays, and spore distributions were observed with electron microscopy. PMID:23719028

  5. A Novel Anti-Inflammatory Effect for High Density Lipoprotein.

    PubMed

    Cameron, Scott J; Morrell, Craig N; Bao, Clare; Swaim, AnneMarie F; Rodriguez, Annabelle; Lowenstein, Charles J

    2015-01-01

    High density lipoprotein has anti-inflammatory effects in addition to mediating reverse cholesterol transport. While many of the chronic anti-inflammatory effects of high density lipoprotein (HDL) are attributed to changes in cell adhesion molecules, little is known about acute signal transduction events elicited by HDL in endothelial cells. We now show that high density lipoprotein decreases endothelial cell exocytosis, the first step in leukocyte trafficking. ApoA-I, a major apolipoprotein of HDL, mediates inhibition of endothelial cell exocytosis by interacting with endothelial scavenger receptor-BI which triggers an intracellular protective signaling cascade involving protein kinase C (PKC). Other apolipoproteins within the HDL particle have only modest effects upon endothelial exocytosis. Using a human primary culture of endothelial cells and murine apo-AI knockout mice, we show that apo-AI prevents endothelial cell exocytosis which limits leukocyte recruitment. These data suggest that high density lipoprotein may inhibit diseases associated with vascular inflammation in part by blocking endothelial exocytosis. PMID:26680360

  6. Probabilistic Fatigue Life Analysis of High Density Electronics Packaging

    NASA Technical Reports Server (NTRS)

    Moore, N. R.; Kolawa, E. A.; Sutharshana, S.; Newlin, L. E.; Creager, M.

    1996-01-01

    The fatigue of thin film metal interconnections in high density electronics packaging subjected to thermal cycling has been evaluated using a probabilistic fracture mechanics methodology. This probabilistic methodology includes characterization of thin film stress using an experimentally calibrated finite element model and simulation of flaw growth in the thin films using a stochastic crack growth model.

  7. Crater Fill

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03082 Crater Fill

    This VIS image shows part of the floor of an unnamed crater located between the Hellas and Argyre Basins. At some point in time the entire floor of the crater was filled by material. That material is now being eroded away to form the depressions seen in the center and bottom of the image.

    Image information: VIS instrument. Latitude 46.6S, Longitude 5.0E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. Polyethylene Glycol 3350

    MedlinePlus

    Polyethylene glycol 3350 comes as a powder to be mixed with a liquid and taken by mouth. It is usually taken once a day as needed for up to ... to produce a bowel movement.To use the powder, follow these steps: If you are using polyethylene ...

  9. Performance of high-density-carbon (HDC) ablator implosion experiments on the National Ignition Facility (NIF)

    NASA Astrophysics Data System (ADS)

    MacKinnon, Andy

    2013-10-01

    A series of experiments on the National Ignition Facility (NIF) have been performed to measure high-density carbon (HDC) ablator performance for indirect drive inertial confinement fusion (ICF). HDC is a very promising ablator material; being 3x denser than plastic, it absorbs more hohlraum x-rays, leading to higher implosion efficiency. For the HDC experiments the NIF laser generated shaped laser pulses with peak power up to 410 TW and total energy of 1.3 MJ. Pulse shapes were designed to drive 2, 3 or 4 shocks in cryogenic layered implosions. The 2-shock pulse, with a designed fuel adiabat of ~3 is 6-7ns in duration, allowing use of near vacuum hohlraums, which greatly increases the coupling efficiency due to low backscatter losses. Excellent results were obtained for 2,3 and 4 shock pulses. In particular a deuterium-tritium gas filled HDC capsule driven by a 4-shock pulse in a gas-filled hohlraum produced a neutron yield of 1.6 × 1015, a record for a non-cryogenically layered capsule driven by a gas-filled hohlraum. The first 2-shock experiment used a vacuum hohlraum to drive a DD gas filled HDC capsule with a 6.5 ns, laser pulse. This hohlraum was 40% more efficient than the gas-filled counterpart used for 3 and 4 shock experiments, producing near 1D performance at 11 x convergence ratio, peak radiation temperature of 317 eV, 98% laser-hohlraum coupling, and DD neutron yield of 2.2e13, a record for a laser driven DD implosion. The HDC campaigns will be presented, including options for pushing towards the alpha dominated regime. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  10. Macrophage phagocytosis of polyethylene particulate in vitro.

    PubMed

    Voronov, I; Santerre, J P; Hinek, A; Callahan, J W; Sandhu, J; Boynton, E L

    1998-01-01

    In this study, an in vitro model has been developed to examine the interactions of macrophages with ultrahigh molecular-weight polyethylene (UHMWPE) and high-density polyethylene (HDPE) particles. Polyethylene particles are the major constituent of the material debris formed as a result of orthopedic implant wear. However, the study of polyethylene particle interactions with cells has been limited. UHMWPE (18-20 microns) and HDPE (4-10 microns) were suspended in soluble collagen type I and subsequently solidified on glass coverslips. The particle chemistry was characterized by Fourier transform infra-red spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Mouse cell line macrophages (IC-21) were established on the collagen-particle substrata and maintained for up to 24 h. The response of the cells to the particles was examined by light and transmission electron microscopy (LM and TEM), as well as by scanning electron microscopy (SEM), and compared to cells on control collagen surfaces without particles. Histological analysis of the samples revealed that the macrophages surrounded larger particles (18-20 microns) and the cells appeared to be attached to the surface of the particles, and the smaller particles (4-10 microns) had been phagocytosed within 2 h. Inflammatory cytokines (TNF-alpha, IL-1 alpha, IL-1 beta, and IL-6), lysosomal enzymes (beta-galactosidase and hexosaminidase), and prostaglandin E2 were released into the medium, and IL-1 alpha, IL-1 beta, PGE2, beta-galactosidase, and hexosaminidase levels were significantly increased over collagen control values. The results demonstrate active phagochemotaxis by macrophages for wear particulates and validate this model as a means of studying the specific in vitro interactions of polyethylene with cells. PMID:9429095

  11. Noise reduction in muon tomography for detecting high density objects

    NASA Astrophysics Data System (ADS)

    Benettoni, M.; Bettella, G.; Bonomi, G.; Calvagno, G.; Calvini, P.; Checchia, P.; Cortelazzo, G.; Cossutta, L.; Donzella, A.; Furlan, M.; Gonella, F.; Pegoraro, M.; Rigoni Garola, A.; Ronchese, P.; Squarcia, S.; Subieta, M.; Vanini, S.; Viesti, G.; Zanuttigh, P.; Zenoni, A.; Zumerle, G.

    2013-12-01

    The muon tomography technique, based on multiple Coulomb scattering of cosmic ray muons, has been proposed as a tool to detect the presence of high density objects inside closed volumes. In this paper a new and innovative method is presented to handle the density fluctuations (noise) of reconstructed images, a well known problem of this technique. The effectiveness of our method is evaluated using experimental data obtained with a muon tomography prototype located at the Legnaro National Laboratories (LNL) of the Istituto Nazionale di Fisica Nucleare (INFN). The results reported in this paper, obtained with real cosmic ray data, show that with appropriate image filtering and muon momentum classification, the muon tomography technique can detect high density materials, such as lead, albeit surrounded by light or medium density material, in short times. A comparison with algorithms published in literature is also presented.

  12. Advanced short haul systems in high density markets

    NASA Technical Reports Server (NTRS)

    Galloway, T. L.

    1975-01-01

    The design requirements, performance, economics, and noise aspects of STOL and VTOL conceptual aircraft developed for short haul air transportation are reviewed, along with the characteristics of areas of high-density annual passenger flow in which the aircraft are intended to operate. It is shown that aircraft of 100 to 200 passenger capacity provide the best return on investment in high density markets. The various STOL propulsive lift concepts have the same general trends with field length; their wing loadings are 20 to 30 pounds per square foot higher than the nonpropulsive lift concepts. A comparison of the aircraft under consideration shows that no one aircraft concept will be optimum for all future operational environments.

  13. High Density Experiments in the HL-1M Tokamak

    NASA Astrophysics Data System (ADS)

    Yan, Long-wen; Yao, Liang-hua; Zhou, Yan; Liu, Yong; Wang, En-yao; HL-1M Team

    2000-10-01

    The plasma performance of high density has been investigated in the HL-1M Tokamak. Different density limits are given for three fueling methods i.e. gas puffing, pellet injection and molecular beam injection (MBI). The maximum Murakami constant is CM = 3.4 × 1019 m-2T-1 for Ohmic discharge. A maximum line-averaged density of 8.2 × 1019 m-3 has been achieved for Ohmic discharge at qa = 4.4. A 1.4 times of the Greenwald limit is obtained at Ip = 120 kA. The rising rates and peak factors of density are discussed. The plasma confinement of high density is analyzed, including the behavior of density limit disruption.

  14. High-density FRC formation studies on FRX-L.

    SciTech Connect

    Taccetti, J. M.; Intrator, Thomas; Zhang, S.; Wurden, G. A.; Begay, D. W.; Mignardot, E. R.; Waganaar, W. J.; Siemon, R. E.; Tuszewski, M. G.; Sanchez, P. G.; Degnan, J. H.; Sommars, W.

    2002-01-01

    FRX-L (Field Reversed configuration experiment - Liner) is a magnetized-target injector for magnetized target fusion (MTF) experiments. It was designed with the goal of producing high-density n-1017 cm3 field reversed configurations (FRCs) and translating them into an aluminum liner (1-mm thick, 10-cm diameter cylindrical shell) for further compression to fusion conditions. Although operation at these high densities leads to shorter FRC lifetimes, our application requires thlat the plasma live only long enough to be translated and compressed, or on the order of 10-20 ps. Careful study of FRC formation in situ will be done in the present experiment to differentiate between effects introduced in future experiments by translation, trapping, and compression of the FRC. We present current results on the optimization of the FRC formation process on RX-L and compare the results with those from past experiments.

  15. PREPARATION OF HIGH-DENSITY THORIUM OXIDE SPHERES

    DOEpatents

    McNees, R.A. Jr.; Taylor, A.J.

    1963-12-31

    A method of preparing high-density thorium oxide spheres for use in pellet beds in nuclear reactors is presented. Sinterable thorium oxide is first converted to free-flowing granules by means such as compression into a compact and comminution of the compact. The granules are then compressed into cubes having a density of 5.0 to 5.3 grams per cubic centimeter. The cubes are tumbled to form spheres by attrition, and the spheres are then fired at 1250 to 1350 deg C. The fired spheres are then polished and fired at a temperature above 1650 deg C to obtain high density. Spherical pellets produced by this method are highly resistant to mechanical attrition hy water. (AEC)

  16. New pitfalls of high-density postmortem computed tomography.

    PubMed

    Kanazawa, Ayumi; Hyodoh, Hideki; Watanabe, Satoshi; Fukuda, Marika; Baba, Miho; Okazaki, Shunichiro; Mizuo, Keisuke; Hayashi, Etsuko; Inoue, Hiromasa

    2014-09-01

    An 80-year-old female was transferred to the hospital due to a traffic accident. Multiple cranial bone fractures with intracranial hemorrhage and intracranial air were detected. Despite treatment, the patient died after 6h. Twenty-one hours after the patient died, her whole body was scanned by postmortem CT, and a region of high density was detected within the left putamen. The autopsy revealed a cerebral contusion and multiple skull base fractures. Moreover, superabsorbent polymers (SAPs) were found within the left lateral ventricle and adjacent to the putamen, which appeared as a high-density lesion on postmortem CT at the left putamen, where the SAPs were compacted. Both ante- and postmortem conditions should be considered to prevent misdiagnoses based only on postmortem CT. PMID:24916862

  17. Advanced short haul aircraft for high density markets

    NASA Technical Reports Server (NTRS)

    Galloway, T. L.

    1977-01-01

    The short haul (less than 500 miles) passenger enplanements represent about 50% of the total domestic enplanements. These can be distinguished by the annual passenger flow for a given city pair and classified into low, medium and high densiy markets. NASA studies have investigated various advanced short haul aircraft concepts that have potential application in these three market areas. Although advanced operational techniques impact all market densities, advanced vehicle design concepts such as RTOL, STOL and VTOL have the largest impact in the high density markets. This paper summarizes the results of NASA sponsored high density short haul air transportation systems studies and briefly reviews NASA sponsored advanced VTOL conceptual aircraft design studies. Trends in vehicle characteristics and operational requirements will be indicated in addition to economic suitability and impact on the community.

  18. Laterally stacked glass substrates with high density electrical feedthroughs

    NASA Astrophysics Data System (ADS)

    Tanaka, Shuji; Fujimoto, Satoshi; Ito, Osamu; Choe, Seong-Hun; Esashi, Masayoshi

    2007-03-01

    This paper reports a novel method to produce high density feedthrough glass wafers with sufficient thickness for the packaging and interconnection of high density array micro electromechanical systems (MEMS). Pyrex glass wafers with thin film metal lines on the surface are stacked and bonded with each other using phenyl methyl siloxane-based adhesive. The stacked glass wafer block is then sliced using a wire saw as the slicing surfaces cross the adhesive bonding interfaces vertically. Prototyped feedthrough glass wafers were subjected to anodic bonding to a silicon wafer with diaphragms. The anodic bonding was successful, but hermetic sealing was not achieved. The bending of the bonded sample can be reduced by annealing the sample at 400 °C in a vacuum before anodic bonding.

  19. Fluid hydrogen at high density - The plasma phase transition

    NASA Technical Reports Server (NTRS)

    Saumon, D.; Chabrier, G.

    1989-01-01

    A new model equation of state is applied, based on realistic interparticle potentials and a self-consistent treatment of the internal levels, to fluid hydrogen at high density. This model shows a strong connection between molecular dissociation and pressure ionization. The possibility of a first-order plasma phase transition is considered, and for which both the evolution in temperature and the critical point is given.

  20. High-Density Amorphous Ice, the Frost on Interstellar Grains

    NASA Technical Reports Server (NTRS)

    Jenniskens, P.; Blake, D. F.; Wilson, M. A.; Pohorille, A.

    1995-01-01

    Most water ice in the universe is in a form which does not occur naturally on Earth and of which only minimal amounts have been made in the laboratory. We have encountered this 'high-density amorphous ice' in electron diffraction experiments of low-temperature (T less than 30 K) vapor-deposited water and have subsequently modeled its structure using molecular dynamics simulations. The characteristic feature of high-density amorphous ice is the presence of 'interstitial' oxygen pair distances between 3 and 4 A. However, we find that the structure is best described as a collapsed lattice of the more familiar low-density amorphous form. These distortions are frozen in at temperatures below 38 K because, we propose, it requires the breaking of one hydrogen bond, on average, per molecule to relieve the strain and to restructure the lattice to that of low-density amorphous ice. Several features of astrophysical ice analogs studied in laboratory experiments are readily explained by the structural transition from high-density amorphous ice into low-density amorphous ice. Changes in the shape of the 3.07 gm water band, trapping efficiency of CO, CO loss, changes in the CO band structure, and the recombination of radicals induced by low-temperature UV photolysis all covary with structural changes that occur in the ice during this amorphous to amorphous transition. While the 3.07 micrometers ice band in various astronomical environments can be modeled with spectra of simple mixtures of amorphous and crystalline forms, the contribution of the high-density amorphous form nearly always dominates.

  1. Next generation high density self assembling functional protein arrays

    PubMed Central

    Ramachandran, Niroshan; Raphael, Jacob V.; Hainsworth, Eugenie; Demirkan, Gokhan; Fuentes, Manuel G.; Rolfs, Andreas; Hu, Yanhui; LaBaer, Joshua

    2009-01-01

    We report a high-density self assembling protein microarray that displays thousands of proteins, produced and captured in situ from immobilized cDNA templates. Over 1500 unique cDNAs were tested with > 90% success with nearly all proteins displaying yields within 2 fold of the mean, minimal sample variation and good day to day reproducibility. The displayed proteins revealed selective protein interactions. This method will enable various experimental approaches to study protein function in high throughput. PMID:18469824

  2. Near-vacuum hohlraums for driving fusion implosions with high density carbon ablatorsa)

    NASA Astrophysics Data System (ADS)

    Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; Meezan, N. B.; Mackinnon, A. J.; Ho, D. D.; Jones, O. S.; Khan, S.; Milovich, J. L.; Ross, J. S.; Amendt, P.; Casey, D.; Celliers, P. M.; Pak, A.; Peterson, J. L.; Ralph, J.; Rygg, J. R.

    2015-05-01

    Recent experiments at the National Ignition Facility [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] have explored driving high-density carbon ablators with near-vacuum hohlraums, which use a minimal amount of helium gas fill. These hohlraums show improved efficiency relative to conventional gas-filled hohlraums in terms of minimal backscatter, minimal generation of suprathermal electrons, and increased hohlraum-capsule coupling. Given these advantages, near-vacuum hohlraums are a promising choice for pursuing high neutron yield implosions. Long pulse symmetry control, though, remains a challenge, as the hohlraum volume fills with material. Two mitigation methodologies have been explored, dynamic beam phasing and increased case-to-capsule ratio (larger hohlraum size relative to capsule). Unexpectedly, experiments have demonstrated that the inner laser beam propagation is better than predicted by nominal simulations, and an enhanced beam propagation model is required to match measured hot spot symmetry. Ongoing work is focused on developing a physical model which captures this enhanced propagation and on utilizing the enhanced propagation to drive longer laser pulses than originally predicted in order to reach alpha-heating dominated neutron yields.

  3. Gas-solid flow characteristics in high-density CFB

    NASA Astrophysics Data System (ADS)

    Wang, Xue-yao; Fan, Bao-guo; Wang, Sheng-dian; Xu, Xiang; Xiao, Yun-han

    2012-08-01

    The gas-solid flow characteristics in the riser of a high density CFB of square (0.27 m×0.27 m×10.4 m) or circular ( ϕ 0.187m×10.4 m) cross section, using Geldart B particles (quartz sand), was investigated experimentally. The influence of riser structure on the hydrodynamic behaviors of a high-density circulating fluidized bed was investigated. The solid circulation rate was up to 321 kg/(m2s) with the circular cross-section under the operating conditions of the main bed air velocity 12.1 m/s and loosen wind and back-feed wind flow 25.1 m3/h. Different operating conditions on realizing high density circulation was analyzed, while both solids circulation rate and particle holdup depended highly on operating conditions. The circulating gas-solid flow was accompanied by an evidently-dense character in the riser's bottom zone and became fully developed in the middle and upper zones.

  4. Density limits investigation and high density operation in EAST tokamak

    NASA Astrophysics Data System (ADS)

    Zheng, Xingwei; Li, Jiangang; Hu, Jiansheng; Liu, Haiqing; Jie, Yinxian; Wang, Shouxin; Li, Jiahong; Duan, Yanming; Li, Miaohui; Li, Yongchun; Zhang, Ling; Ye, Yang; Yang, Qingquan; Zhang, Tao; Cheng, Yingjie; Xu, Jichan; Wang, Liang; Xu, Liqing; Zhao, Hailin; Wang, Fudi; Lin, Shiyao; Wu, Bin; Lyu, Bo; Xu, Guosheng; Gao, Xiang; Shi, Tonghui; He, Kaiyang; Lan, Heng; Chu, Nan; Cao, Bin; Sun, Zhen; Zuo, Guizhong; Ren, Jun; Zhuang, Huidong; Li, Changzheng; Yuan, Xiaolin; Yu, Yaowei; Wang, Houyin; Chen, Yue; Wu, Jinhua; EAST Team

    2016-05-01

    Increasing the density in a tokamak is limited by the so-called density limit, which is generally performed as an appearance of disruption causing loss of plasma confinement, or a degradation of high confinement mode which could further lead to a H  →  L transition. The L-mode and H-mode density limit has been investigated in EAST tokamak. Experimental results suggest that density limits could be triggered by either edge cooling or excessive central radiation. The L-mode density limit disruption is generally triggered by edge cooling, which leads to the current profile shrinkage and then destabilizes a 2/1 tearing mode, ultimately resulting in a disruption. The L-mode density limit scaling agrees well with the Greenwald limit in EAST. The observed H-mode density limit in EAST is an operational-space limit with a value of 0.8∼ 0.9{{n}\\text{GW}} . High density H-mode heated by neutral beam injection (NBI) and lower hybrid current drive (LHCD) are analyzed, respectively. The constancy of the edge density gradients in H-mode indicates a critical limit caused perhaps by e.g. ballooning induced transport. The maximum density is accessed at the H  →  L transition which is generally caused by the excessive core radiation due to high Z impurities (Fe, Cu). Operating at a high density (>2.8× {{10}19} {{\\text{m}}-3} ) is favorable for suppressing the beam shine through NBI. High density H-mode up to 5.3× {{10}19}{{\\text{m}}-3}~≤ft(∼ 0.8{{n}\\text{GW}}\\right) could be sustained by 2 MW 4.6 GHz LHCD alone, and its current drive efficiency is studied. Statistics show that good control of impurities and recycling facilitate high density operation. With careful control of these factors, high density up to 0.93{{n}\\text{GW}} stable H-mode operation was carried out heated by 1.7 MW LHCD and 1.9 MW ion cyclotron resonance heating with supersonic molecular beam injection fueling.

  5. Characterization of the high density plasma etching process of CCTO thin films for the fabrication of very high density capacitors

    NASA Astrophysics Data System (ADS)

    Altamore, C.; Tringali, C.; Sparta', N.; Di Marco, S.; Grasso, A.; Ravesi, S.

    2010-02-01

    In this work the feasibility of CCTO (Calcium Copper Titanate) patterning by etching process is demonstrated and fully characterized in a hard to etch materials etcher. CCTO sintered in powder shows a giant relative dielectric constant (105) measured at 1 MHz at room temperature. This feature is furthermore coupled with stability from 101 Hz to 106 Hz in a wide temperature range (100K - 600K). In principle, this property can allow to fabricate very high capacitance density condenser. Due to its perovskite multi-component structure, CCTO can be considered a hard to etch material. For high density capacitor fabrication, CCTO anisotropic etching is requested by using high density plasma. The behavior of etched CCTO was studied in a HRe- (High Density Reflected electron) plasma etcher using Cl2/Ar chemistry. The relationship between the etch rate and the Cl2/Ar ratio was also studied. The effects of RF MHz, KHz Power and pressure variation, the impact of HBr addiction to the Cl2/Ar chemistry on the CCTO etch rate and on its selectivity to Pt and photo resist was investigated.

  6. High-density support matrices: Key to the deep borehole disposal of spent nuclear fuel

    NASA Astrophysics Data System (ADS)

    Gibb, F. G. F.; McTaggart, N. A.; Travis, K. P.; Burley, D.; Hesketh, K. W.

    2008-03-01

    Deep (4-5 km) boreholes are emerging as a safe, secure, environmentally sound and potentially cost-effective option for disposal of high-level radioactive wastes, including plutonium. One reason this option has not been widely accepted for spent fuel is because stacking the containers in a borehole could create load stresses threatening their integrity with potential for releasing highly mobile radionuclides like 129I before the borehole is filled and sealed. This problem can be overcome by using novel high-density support matrices deployed as fine metal shot along with the containers. Temperature distributions in and around the disposal are modelled to show how decay heat from the fuel can melt the shot within weeks of disposal to give a dense liquid in which the containers are almost weightless. Finally, within a few decades, this liquid will cool and solidify, entombing the waste containers in a base metal sarcophagus sealed into the host rock.

  7. High-density carbon capsule experiments on the national ignition facility.

    PubMed

    Ross, J S; Ho, D; Milovich, J; Döppner, T; McNaney, J; MacPhee, A G; Hamza, A; Biener, J; Robey, H F; Dewald, E L; Tommasini, R; Divol, L; Le Pape, S; Berzak Hopkins, L; Celliers, P M; Landen, O; Meezan, N B; Mackinnon, A J

    2015-02-01

    Indirect-drive implosions with a high-density carbon (HDC) capsule were conducted on the National Ignition Facility (NIF) to test HDC properties as an ablator material for inertial confinement fusion. A series of five experiments were completed with 76-μm-thick HDC capsules using a four-shock laser pulse optimized for HDC. The pulse delivered a total energy of 1.3 MJ with a peak power of 360 TW. The experiment demonstrated good laser to target coupling (∼90%) and excellent nuclear performance. A deuterium and tritium gas-filled HDC capsule implosion produced a neutron yield of 1.6×10^{15}±3×10(13), a yield over simulated in one dimension of 70%. PMID:25768451

  8. High-density carbon capsule experiments on the national ignition facility

    NASA Astrophysics Data System (ADS)

    Ross, J. S.; Ho, D.; Milovich, J.; Döppner, T.; McNaney, J.; MacPhee, A. G.; Hamza, A.; Biener, J.; Robey, H. F.; Dewald, E. L.; Tommasini, R.; Divol, L.; Le Pape, S.; Hopkins, L. Berzak; Celliers, P. M.; Landen, O.; Meezan, N. B.; Mackinnon, A. J.

    2015-02-01

    Indirect-drive implosions with a high-density carbon (HDC) capsule were conducted on the National Ignition Facility (NIF) to test HDC properties as an ablator material for inertial confinement fusion. A series of five experiments were completed with 76 -μ m -thick HDC capsules using a four-shock laser pulse optimized for HDC. The pulse delivered a total energy of 1.3 MJ with a peak power of 360 TW. The experiment demonstrated good laser to target coupling (˜90 % ) and excellent nuclear performance. A deuterium and tritium gas-filled HDC capsule implosion produced a neutron yield of 1.6 ×1015±3 ×1013 , a yield over simulated in one dimension of 70 % .

  9. High-Density Carbon Ablator Experiments on the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Ross, James; Macphee, Andrew; McNaney, James; Doeppner, Tilo; Pak, Art; Rygg, Ryan; Benedetti, Robin; Town, Richard; Bradley, David; Dewald, Edward; Tommasini, Ricardo; Milovich, Jose; Berzak-Hopkins, Laura; Moody, John; Callahan, Debbi; Hamza, Alex; Biener, Juergen; Ho, Darwin; Storm, Eric; Kilkenny, Joe; Landen, Otto; Lindl, John; Edwards, John; Meezan, Nathan; Mackinno, Andrew

    2013-10-01

    A series of experiments on the National Ignition Facility (NIF) have been preformed to measure high-density carbon (HDC) ablator performance for indirect drive inertial confinement fusion (ICF). The NIF laser was used to generate a shaped laser pulse with a peak power of 360 TW and a total energy of 1.3 MJ. The total neutron yield, ion temperature, neutron bang time and x-ray bang time were measured and compared to simulations. A deuterium-tritium filled HDC capsule recently produced a neutron yield of 1.6 × 1015, the current record for laser driven ICF. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by LDRD-11-ERD-075.

  10. Extensional Flow Induced Crystallization of Polyethylene

    NASA Astrophysics Data System (ADS)

    Nicholson, David; Locker, C. Rebecca; Tsou, Andy; Rutledge, Gregory

    2014-03-01

    The majority of manufactured polyethylene is used in films mostly through the blown film fabrication process where extensional flow induced crystallization is a critical component in affecting the development of crystalline morphology and amorphous topology. In order to optimize the blown film performance, it is critical to understand the mechanism of extensional flow induced crystallization of polyethylene. Model high density polyethylene with a Mn of 20,000 g/mol and a PDI (polydispersity) of 2 and lower were synthesized by organometallic catalysts. Extensional flow induced crystallization of these materials was measured using the SER (Sentmanat Extensional Rheometer) either at a given rate with varying temperatures or vice versa. A continuum model was applied to analyze the flow induced crystallization data. All samples after extensional flow were quenched in ice water and the resulting morphology was characterized using SAXS and WAXS. The extensional rate was found to be effective in modifying morphology whereas the temperature was not; neither temperature nor strain rate affected the final film crystallinity. With an increase in extensional rate, crystallites became thinner and narrower with potentially higher connectivity which could lead to higher toughness.

  11. Grafting functional antioxidants on highly crosslinked polyethylene

    NASA Astrophysics Data System (ADS)

    Al-Malaika, S.; Riasat, S.; Lewucha, C.

    2016-05-01

    The problem of interference of antioxidants, such as hindered phenols, with peroxide-initiated crosslinking of polyethylene was addressed through the use of functional (reactive) graftable antioxidants (g-AO). Reactive derivatives of hindered phenol and hindered amine antioxidants were synthesised, characterised and used to investigate their grafting reactions in high density polyethylene; both non-crosslinked (PE) and highly peroxide-crosslinked (PEXa). Assessment of the extent of in-situ grafting of the antioxidants, their retention after exhaustive solvent extraction in PE and PEXa, and the stabilising performance of the grafted antioxidants (g-AO) in the polymer were examined and benchmarked against conventionally stabilised crosslinked & non-crosslinked polyethylene. It was shown that the functional antioxidants graft to a high extent in PEXa, and that the level of interference of the g-AOs with the polymer crosslinking process was minimal compared to that of conventional antioxidants which bear the same antioxidant function. The much higher level of retention of the g-AOs in PEXa after exhaustive solvent extraction, compared to that of the corresponding conventional antioxidants, accounts for their superior long-term thermal stabilising performance under severe extractive conditions.

  12. Near-vacuum hohlraums for driving fusion implosions with high density carbon ablators

    NASA Astrophysics Data System (ADS)

    Berzak Hopkins, Laura

    2014-10-01

    Achieving ignition requires reaching fast implosion velocities, which highlights the need for a highly efficient hohlraum to drive indirect-drive inertial confinement fusion implosions. Gas-filled hohlraums are typically utilized due to the pulse length (15-20 ns) needed to drive plastic (CH) capsules. With the recent use of 3× denser high-density carbon (HDC) capsules, ignition pulses can be less than 10 ns in duration, providing the opportunity to utilize near-vacuum hohlraums (NVH) to drive ignition-relevant implosions on the National Ignition Facility (NIF) with minimal laser-plasma instabilities which complicate standard gas-filled hohlraums. Initial NVH implosions on the NIF have demonstrated coupling efficiency significantly higher than observed in gas-filled hohlraums - backscatter losses less than 2% and virtually no suprathermal electron generation. A major design challenge for the NVH is symmetry control. Without tamping gas, the hohlraum wall quickly expands filling the volume with gold plasma. However, results to-date indicate that the inner-cone beams propagate freely to the hohlraum wall for at least 6.5 ns. With minimal predicted cross-beam power transfer, this propagation enables symmetry control via dynamic beam phasing - time-dependent direct adjustment of the inner- and outer-cone laser pulses. A series of experiments with an HDC ablator and NVH culminated in a 6 ns, 1.2 MJ cryogenic DT layered implosion yielding 1.8 × 1015 neutrons--significantly higher yield than any CH implosion at comparable energy. This implosion reached an ignition-relevant velocity -350 km/s - with no observed ablator mix in the hot spot. Recent experiments have explored two-shock designs in a larger, 6.72 mm hohlraum, and upcoming experiments will incrementally extend the pulse duration toward a 9 ns long, three-shock ignition design. Prepared by LLNL under Contract DE-AC52-07NA27344.

  13. Extended length microchannels for high density high throughput electrophoresis systems

    DOEpatents

    Davidson, James C.; Balch, Joseph W.

    2000-01-01

    High throughput electrophoresis systems which provide extended well-to-read distances on smaller substrates, thus compacting the overall systems. The electrophoresis systems utilize a high density array of microchannels for electrophoresis analysis with extended read lengths. The microchannel geometry can be used individually or in conjunction to increase the effective length of a separation channel while minimally impacting the packing density of channels. One embodiment uses sinusoidal microchannels, while another embodiment uses plural microchannels interconnected by a via. The extended channel systems can be applied to virtually any type of channel confined chromatography.

  14. High density electronic circuit and process for making

    DOEpatents

    Morgan, William P.

    1999-01-01

    High density circuits with posts that protrude beyond one surface of a substrate to provide easy mounting of devices such as integrated circuits. The posts also provide stress relief to accommodate differential thermal expansion. The process allows high interconnect density with fewer alignment restrictions and less wasted circuit area than previous processes. The resulting substrates can be test platforms for die testing and for multi-chip module substrate testing. The test platform can contain active components and emulate realistic operational conditions, replacing shorts/opens net testing.

  15. High density electronic circuit and process for making

    DOEpatents

    Morgan, W.P.

    1999-06-29

    High density circuits with posts that protrude beyond one surface of a substrate to provide easy mounting of devices such as integrated circuits are disclosed. The posts also provide stress relief to accommodate differential thermal expansion. The process allows high interconnect density with fewer alignment restrictions and less wasted circuit area than previous processes. The resulting substrates can be test platforms for die testing and for multi-chip module substrate testing. The test platform can contain active components and emulate realistic operational conditions, replacing shorts/opens net testing. 8 figs.

  16. High Density Thermal Energy Storage with Supercritical Fluids

    NASA Technical Reports Server (NTRS)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  17. Enhanced Configurational Entropy in High-Density Nanoconfined Bilayer Ice

    NASA Astrophysics Data System (ADS)

    Corsetti, Fabiano; Zubeltzu, Jon; Artacho, Emilio

    2016-02-01

    A novel kind of crystal order in high-density nanoconfined bilayer ice is proposed from molecular dynamics and density-functional theory simulations. A first-order transition is observed between a low-temperature proton-ordered solid and a high-temperature proton-disordered solid. The latter is shown to possess crystalline order for the oxygen positions, arranged on a close-packed triangular lattice with A A stacking. Uniquely among the ice phases, the triangular bilayer is characterized by two levels of disorder (for the bonding network and for the protons) which results in a configurational entropy twice that of bulk ice.

  18. Enhanced Configurational Entropy in High-Density Nanoconfined Bilayer Ice.

    PubMed

    Corsetti, Fabiano; Zubeltzu, Jon; Artacho, Emilio

    2016-02-26

    A novel kind of crystal order in high-density nanoconfined bilayer ice is proposed from molecular dynamics and density-functional theory simulations. A first-order transition is observed between a low-temperature proton-ordered solid and a high-temperature proton-disordered solid. The latter is shown to possess crystalline order for the oxygen positions, arranged on a close-packed triangular lattice with AA stacking. Uniquely among the ice phases, the triangular bilayer is characterized by two levels of disorder (for the bonding network and for the protons) which results in a configurational entropy twice that of bulk ice. PMID:26967426

  19. Probing topological relations between high-density and low-density regions of 2MASS with hexagon cells

    SciTech Connect

    Wu, Yongfeng; Xiao, Weike

    2014-02-01

    We introduced a new two-dimensional (2D) hexagon technique for probing the topological structure of the universe in which we mapped regions of the sky with high and low galaxy densities onto a 2D lattice of hexagonal unit cells. We defined filled cells as corresponding to high-density regions and empty cells as corresponding to low-density regions. The numbers of filled cells and empty cells were kept the same by controlling the size of the cells. By analyzing the six sides of each hexagon, we could obtain and compare the statistical topological properties of high-density and low-density regions of the universe in order to have a better understanding of the evolution of the universe. We applied this hexagonal method to Two Micron All Sky Survey data and discovered significant topological differences between the high-density and low-density regions. Both regions had significant (>5σ) topological shifts from both the binomial distribution and the random distribution.

  20. Operating condition limitations of high density QCW arrays

    NASA Astrophysics Data System (ADS)

    Junghans, Jeremy; Levy, Joseph; Feeler, Ryan

    2012-03-01

    Northrop Grumman Cutting Edge Optronics (NGCEO) has developed a laser diode array package with minimal bar-tobar spacing. These High Density Stack (HDS) packages allow for a power density increase on the order of ~ 2.5x when compared to industry-standard arrays. Power densities as high as 15 kW/cm2 can be achieved when operated at 200 W/bar. This work provides a detailed description of the duty factor, pulse width and power limitations of high density arrays. The absence of the interposing heatsinks requires that all of the heat generated by the interior bars must travel through the adjacent bars to the electrical contacts. This results in limitations to the allowable operating envelope of the HDS arrays. Thermal effects such as wavelength shifts across large HDS arrays are discussed. An overview of recent HDS design and manufacturing improvements is also presented. These improvements result in reliable operation at higher power densities and increased duty factors. A comparison of the effect of bar geometry on HDS performance is provided. Test data from arrays featuring these improvements based on both full 1 cm wide diode bars as well as 3 mm wide mini-bars is also presented.

  1. System design for OFDM systems with high-density constellations

    NASA Astrophysics Data System (ADS)

    Gu, Jian

    2001-10-01

    This paper addresses issues in designing OFDM systems with high-density constellations. To achieve high data throughput, many high-speed OFDM systems such as HiperLAN2 and IEEE 802.11a use high-density constellations such as 64QAM to reach up to 54Mbits/s over a 20 MHz frequency bandwidth. Compared with low-density constellation modulations, OFDM systems using M-QAM (M>=64) are very sensitive to analog circuits/components variations causing so-called I-Q imbalances. Moreover, for the purpose of high integration level and low cost, simple front-end radio/analog architectures such as direct conversion and low-IF are desirable but such architectures are even more sensitive to circuitry and component variation. We have developed a patent-pending technology called IQ-Balancing, which removes the adverse effect of I-Q imbalance and enables OFDM systems to have high tolerance to circuitry and component variations. With IQ-Balancing technology, direct conversion and low-IF architectures become very attractive for high-speed OFDM systems. Exploring further with IQ- balancing technology leads to a simple implementation of software Defined Radio (SDR).

  2. Sparse deconvolution of high-density super-resolution images

    PubMed Central

    Hugelier, Siewert; de Rooi, Johan J.; Bernex, Romain; Duwé, Sam; Devos, Olivier; Sliwa, Michel; Dedecker, Peter; Eilers, Paul H. C.; Ruckebusch, Cyril

    2016-01-01

    In wide-field super-resolution microscopy, investigating the nanoscale structure of cellular processes, and resolving fast dynamics and morphological changes in cells requires algorithms capable of working with a high-density of emissive fluorophores. Current deconvolution algorithms estimate fluorophore density by using representations of the signal that promote sparsity of the super-resolution images via an L1-norm penalty. This penalty imposes a restriction on the sum of absolute values of the estimates of emitter brightness. By implementing an L0-norm penalty – on the number of fluorophores rather than on their overall brightness – we present a penalized regression approach that can work at high-density and allows fast super-resolution imaging. We validated our approach on simulated images with densities up to 15 emitters per μm-2 and investigated total internal reflection fluorescence (TIRF) data of mitochondria in a HEK293-T cell labeled with DAKAP-Dronpa. We demonstrated super-resolution imaging of the dynamics with a resolution down to 55 nm and a 0.5 s time sampling. PMID:26912448

  3. Multiplexed, High Density Electrophysiology with Nanofabricated Neural Probes

    PubMed Central

    Du, Jiangang; Blanche, Timothy J.; Harrison, Reid R.; Lester, Henry A.; Masmanidis, Sotiris C.

    2011-01-01

    Extracellular electrode arrays can reveal the neuronal network correlates of behavior with single-cell, single-spike, and sub-millisecond resolution. However, implantable electrodes are inherently invasive, and efforts to scale up the number and density of recording sites must compromise on device size in order to connect the electrodes. Here, we report on silicon-based neural probes employing nanofabricated, high-density electrical leads. Furthermore, we address the challenge of reading out multichannel data with an application-specific integrated circuit (ASIC) performing signal amplification, band-pass filtering, and multiplexing functions. We demonstrate high spatial resolution extracellular measurements with a fully integrated, low noise 64-channel system weighing just 330 mg. The on-chip multiplexers make possible recordings with substantially fewer external wires than the number of input channels. By combining nanofabricated probes with ASICs we have implemented a system for performing large-scale, high-density electrophysiology in small, freely behaving animals that is both minimally invasive and highly scalable. PMID:22022568

  4. Dispersion Interactions in High-Density Molecular Crystals

    NASA Astrophysics Data System (ADS)

    Csernica, Peter; Maitra, Rahul; Distasio, Robert

    Dispersion interactions are ubiquitous quantum mechanical phenomena arising from correlated electron density fluctuations in molecules and materials. As a key component of non-bonded interactions, dispersion forces play a critical role in determining the structure and stability of molecular crystals. Due to the relative intermolecular separation in high-density molecular crystals, an accurate description of these non-bonded interactions requires the inclusion of terms beyond the asymptotic induced-dipole-induced-dipole (C6 /R6) contribution. In this work, we have developed a first principles based approach within the framework of Density Functional Theory (i.e., that only depends on the charge density n (r)) for capturing the higher-order induced multipolar contributions to the correlation energy. As a first application of this method, we have investigated the structure and stability of the high-density ice molecular crystal polymorphs at the ice VI--ice VII--ice VIII triple point (278K, 2.1GPa) using ab-initio molecular dynamics in the isobaric-isothermal (NpT) ensemble.

  5. Effects of High-Density Impacts on Shielding Capability

    NASA Technical Reports Server (NTRS)

    Christiansen, Eric L.; Lear, Dana M.

    2014-01-01

    Spacecraft are shielded from micrometeoroids and orbital debris (MMOD) impacts to meet requirements for crew safety and/or mission success. In the past, orbital debris particles have been considered to be composed entirely of aluminum (medium-density material) for the purposes of MMOD shielding design and verification. Meteoroids have been considered to be low-density porous materials, with an average density of 1 g/cu cm. Recently, NASA released a new orbital debris environment model, referred to as ORDEM 3.0, that indicates orbital debris contains a substantial fraction of high-density material for which steel is used in MMOD risk assessments [Ref.1]. Similarly, an update to the meteoroid environment model is also under consideration to include a high-density component of that environment. This paper provides results of hypervelocity impact tests and hydrocode simulations on typical spacecraft MMOD shields using steel projectiles. It was found that previous ballistic limit equations (BLEs) that define the protection capability of the MMOD shields did not predict the results from the steel impact tests and hydrocode simulations (typically, the predictions from these equations were too optimistic). The ballistic limit equations required updates to more accurately represent shield protection capability from the range of densities in the orbital debris environment. Ballistic limit equations were derived from the results of the work and are provided in the paper.

  6. An evaluation of serum high density lipoproteins-phospholipids.

    PubMed

    Ide, H; Tsuji, M; Shimada, M; Kondo, T; Fujiya, S; Asanuma, Y; Agishi, Y

    1988-07-01

    Phospholipids in high density lipoproteins (HDL) is being used as a negative risk indicator of atherosclerosis. Phospholipids in HDL may not demonstrate the actual level of HDL-phospholipids when determined by the precipitation or ultracentrifugal methods, because HDL fractions contain very high density lipoproteins (VHDL) and albumin. In the present study, the true level of phospholipids in HDL was estimated using high performance liquid chromatography (HPLC), and it was compared with the level of phospholipids in HDL determined by the precipitation method. Sera from 18 healthy subjects were used as materials. In the HPLC method, the HDL fraction was extracted making sure that it contained no free albumin, which is albumin not bound to phospholipids. The HDL fraction was separated into subfractions. It was found that phospholipids in the VHDL fraction make a 20.2 +/- 7.3% (mean +/- S.D.) part of the total HDL-phospholipids. A large part of the VHDL fraction was constituted of albumin-bound phospholipids. A significant correlation was observed between HDL-phospholipids determined by the precipitation method, which contain albumin, and the actual HDL fraction phospholipids determined by HPLC, which do not contain VHDL (r = 0.903, p less than 0.01). These results suggest that HDL-phospholipids values determined by the precipitation method give useful clinical data. PMID:3176021

  7. Loop formation of microtubules during gliding at high density

    NASA Astrophysics Data System (ADS)

    Liu, Lynn; Tüzel, Erkan; Ross, Jennifer L.

    2011-09-01

    The microtubule cytoskeleton, including the associated proteins, forms a complex network essential to multiple cellular processes. Microtubule-associated motor proteins, such as kinesin-1, travel on microtubules to transport membrane bound vesicles across the crowded cell. Other motors, such as cytoplasmic dynein and kinesin-5, are used to organize the cytoskeleton during mitosis. In order to understand the self-organization processes of motors on microtubules, we performed filament-gliding assays with kinesin-1 motors bound to the cover glass with a high density of microtubules on the surface. To observe microtubule organization, 3% of the microtubules were fluorescently labeled to serve as tracers. We find that microtubules in these assays are not confined to two dimensions and can cross one other. This causes microtubules to align locally with a relatively short correlation length. At high density, this local alignment is enough to create 'intersections' of perpendicularly oriented groups of microtubules. These intersections create vortices that cause microtubules to form loops. We characterize the radius of curvature and time duration of the loops. These different behaviors give insight into how crowded conditions, such as those in the cell, might affect motor behavior and cytoskeleton organization.

  8. High-density percutaneous chronic connector for neural prosthetics

    SciTech Connect

    Shah, Kedar G.; Bennett, William J.; Pannu, Satinderpall S.

    2015-09-22

    A high density percutaneous chronic connector, having first and second connector structures each having an array of magnets surrounding a mounting cavity. A first electrical feedthrough array is seated in the mounting cavity of the first connector structure and a second electrical feedthrough array is seated in the mounting cavity of the second connector structure, with a feedthrough interconnect matrix positioned between a top side of the first electrical feedthrough array and a bottom side of the second electrical feedthrough array to electrically connect the first electrical feedthrough array to the second electrical feedthrough array. The two arrays of magnets are arranged to attract in a first angular position which connects the first and second connector structures together and electrically connects the percutaneously connected device to the external electronics, and to repel in a second angular position to facilitate removal of the second connector structure from the first connector structure.

  9. High density propellant for single stage to orbit vehicles

    NASA Technical Reports Server (NTRS)

    Notardonato, J. J.; Masters, P. A.

    1976-01-01

    Mixed mode propulsion concepts are studied for advanced, single stage earth orbital transportation systems (SSTO) for use in the post-1990 time period. These propulsion concepts are based on the sequential and/or parallel use of high density impulse and high specific impulse propellants in a single stage to increase vehicle performance and reduce dry weight. Specifically, the mixed mode concept utilizes two propulsion systems with two different fuels (mode 1 and mode 2) with liquid oxygen as a common oxidizer. Mode 1 engines would burn a high bulk density fuel for lift-off and early ascent to minimize performance penalties associated with carrying fuel tankage to orbit. Mode 2 engines will complete orbital injection utilizing liquid hydrogen as the fuel.

  10. Single-Readout High-Density Memristor Crossbar

    PubMed Central

    Zidan, M. A.; Omran, H.; Naous, R.; Sultan, A.; Fahmy, H. A. H.; Lu, W. D.; Salama, K. N.

    2016-01-01

    High-density memristor-crossbar architecture is a very promising technology for future computing systems. The simplicity of the gateless-crossbar structure is both its principal advantage and the source of undesired sneak-paths of current. This parasitic current could consume an enormous amount of energy and ruin the readout process. We introduce new adaptive-threshold readout techniques that utilize the locality and hierarchy properties of the computer-memory system to address the sneak-paths problem. The proposed methods require a single memory access per pixel for an array readout. Besides, the memristive crossbar consumes an order of magnitude less power than state-of-the-art readout techniques. PMID:26738564

  11. High-density Au nanorod optical field-emitter arrays

    NASA Astrophysics Data System (ADS)

    Hobbs, R. G.; Yang, Y.; Keathley, P. D.; Swanwick, M. E.; Velásquez-García, L. F.; Kärtner, F. X.; Graves, W. S.; Berggren, K. K.

    2014-11-01

    We demonstrate the design, fabrication, characterization, and operation of high-density arrays of Au nanorod electron emitters, fabricated by high-resolution electron beam lithography, and excited by ultrafast femtosecond near-infrared radiation. Electron emission characteristic of multiphoton absorption has been observed at low laser fluence, as indicated by the power-law scaling of emission current with applied optical power. The onset of space-charge-limited current and strong optical field emission has been investigated so as to determine the mechanism of electron emission at high incident laser fluence. Laser-induced structural damage has been observed at applied optical fields above 5 GV m-1, and energy spectra of emitted electrons have been measured using an electron time-of-flight spectrometer.

  12. Neural network based feed-forward high density associative memory

    NASA Technical Reports Server (NTRS)

    Daud, T.; Moopenn, A.; Lamb, J. L.; Ramesham, R.; Thakoor, A. P.

    1987-01-01

    A novel thin film approach to neural-network-based high-density associative memory is described. The information is stored locally in a memory matrix of passive, nonvolatile, binary connection elements with a potential to achieve a storage density of 10 to the 9th bits/sq cm. Microswitches based on memory switching in thin film hydrogenated amorphous silicon, and alternatively in manganese oxide, have been used as programmable read-only memory elements. Low-energy switching has been ascertained in both these materials. Fabrication and testing of memory matrix is described. High-speed associative recall approaching 10 to the 7th bits/sec and high storage capacity in such a connection matrix memory system is also described.

  13. On the high-density expansion for Euclidean random matrices

    NASA Astrophysics Data System (ADS)

    Grigera, T. S.; Martin-Mayor, V.; Parisi, G.; Urbani, P.; Verrocchio, P.

    2011-02-01

    Diagrammatic techniques to compute perturbatively the spectral properties of Euclidean random matrices (ERM) in the high-density regime are introduced and discussed in detail. Such techniques are developed in two alternative and very different formulations of the mathematical problem and are shown to give identical results up to second order in the perturbative expansion. One method, based on writing the so-called resolvent function as a Taylor series, allows us to group the diagrams into a small number of topological classes, providing a simple way to determine the infrared (small momenta) behaviour of the theory up to third order, which is of interest for the comparison with experiments. The other method, which reformulates the problem as a field theory, can instead be used to study the infrared behaviour at any perturbative order.

  14. Single-Readout High-Density Memristor Crossbar.

    PubMed

    Zidan, M A; Omran, H; Naous, R; Sultan, A; Fahmy, H A H; Lu, W D; Salama, K N

    2016-01-01

    High-density memristor-crossbar architecture is a very promising technology for future computing systems. The simplicity of the gateless-crossbar structure is both its principal advantage and the source of undesired sneak-paths of current. This parasitic current could consume an enormous amount of energy and ruin the readout process. We introduce new adaptive-threshold readout techniques that utilize the locality and hierarchy properties of the computer-memory system to address the sneak-paths problem. The proposed methods require a single memory access per pixel for an array readout. Besides, the memristive crossbar consumes an order of magnitude less power than state-of-the-art readout techniques. PMID:26738564

  15. High-density Au nanorod optical field-emitter arrays.

    PubMed

    Hobbs, R G; Yang, Y; Keathley, P D; Swanwick, M E; Velásquez-Garcíia, L F; Kärtner, F X; Graves, W S; Berggren, K K

    2014-11-21

    We demonstrate the design, fabrication, characterization, and operation of high-density arrays of Au nanorod electron emitters, fabricated by high-resolution electron beam lithography, and excited by ultrafast femtosecond near-infrared radiation. Electron emission characteristic of multiphoton absorption has been observed at low laser fluence, as indicated by the power-law scaling of emission current with applied optical power. The onset of space-charge-limited current and strong optical field emission has been investigated so as to determine the mechanism of electron emission at high incident laser fluence. Laser-induced structural damage has been observed at applied optical fields above 5 GV m(-1), and energy spectra of emitted electrons have been measured using an electron time-of-flight spectrometer. PMID:25354583

  16. Ultracold molecular Rydberg physics in a high density environment

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew T.; Pérez-Ríos, Jesús; Robicheaux, F.; Greene, Chris H.

    2016-06-01

    Sufficiently high densities in Bose–Einstein condensates provide favorable conditions for the production of ultralong-range polyatomic molecules consisting of one Rydberg atom and a number of neutral ground state atoms. The chemical binding properties and electronic wave functions of these exotic molecules are investigated analytically via hybridized diatomic states. The effects of the molecular geometry on the system’s properties are studied through comparisons of the adiabatic potential curves and electronic structures for both symmetric and randomly configured molecular geometries. General properties of these molecules with increasing numbers of constituent atoms and in different geometries are presented. These polyatomic states have spectral signatures that lead to non-Lorentzian line-profiles.

  17. High Density Memory Based on Quantum Device Technology

    NASA Technical Reports Server (NTRS)

    vanderWagt, Paul; Frazier, Gary; Tang, Hao

    1995-01-01

    We explore the feasibility of ultra-high density memory based on quantum devices. Starting from overall constraints on chip area, power consumption, access speed, and noise margin, we deduce boundaries on single cell parameters such as required operating voltage and standby current. Next, the possible role of quantum devices is examined. Since the most mature quantum device, the resonant tunneling diode (RTD) can easily be integrated vertically, it naturally leads to the issue of 3D integrated memory. We propose a novel method of addressing vertically integrated bistable two-terminal devices, such as resonant tunneling diodes (RTD) and Esaki diodes, that avoids individual physical contacts. The new concept has been demonstrated experimentally in memory cells of field effect transistors (FET's) and stacked RTD's.

  18. Methods and systems for rapid prototyping of high density circuits

    DOEpatents

    Palmer, Jeremy A.; Davis, Donald W.; Chavez, Bart D.; Gallegos, Phillip L.; Wicker, Ryan B.; Medina, Francisco R.

    2008-09-02

    A preferred embodiment provides, for example, a system and method of integrating fluid media dispensing technology such as direct-write (DW) technologies with rapid prototyping (RP) technologies such as stereolithography (SL) to provide increased micro-fabrication and micro-stereolithography. A preferred embodiment of the present invention also provides, for example, a system and method for Rapid Prototyping High Density Circuit (RPHDC) manufacturing of solderless connectors and pilot devices with terminal geometries that are compatible with DW mechanisms and reduce contact resistance where the electrical system is encapsulated within structural members and manual electrical connections are eliminated in favor of automated DW traces. A preferred embodiment further provides, for example, a method of rapid prototyping comprising: fabricating a part layer using stereolithography and depositing thermally curable media onto the part layer using a fluid dispensing apparatus.

  19. Measurements of uranium mass confined in high density plasmas

    NASA Technical Reports Server (NTRS)

    Stoeffler, R. C.

    1976-01-01

    An X-ray absorption method for measuring the amount of uranium confined in high density, rf-heated uranium plasmas is described. A comparison of measured absorption of 8 keV X-rays with absorption calculated using Beer Law indicated that the method could be used to measure uranium densities from 3 times 10 to the 16th power atoms/cu cm to 5 times 10 to the 18th power atoms/cu cm. Tests were conducted to measure the density of uranium in an rf-heated argon plasma with UF6 infection and with the power to maintain the discharge supplied by a 1.2 MW rf induction heater facility. The uranium density was measured as the flow rate through the test chamber was varied. A maximum uranium density of 3.85 times 10 to the 17th power atoms/cu cm was measured.

  20. High density operation for reactor-relevant power exhaust

    NASA Astrophysics Data System (ADS)

    Wischmeier, M.

    2015-08-01

    With increasing size of a tokamak device and associated fusion power gain an increasing power flux density towards the divertor needs to be handled. A solution for handling this power flux is crucial for a safe and economic operation. Using purely geometric arguments in an ITER-like divertor this power flux can be reduced by approximately a factor 100. Based on a conservative extrapolation of current technology for an integrated engineering approach to remove power deposited on plasma facing components a further reduction of the power flux density via volumetric processes in the plasma by up to a factor of 50 is required. Our current ability to interpret existing power exhaust scenarios using numerical transport codes is analyzed and an operational scenario as a potential solution for ITER like divertors under high density and highly radiating reactor-relevant conditions is presented. Alternative concepts for risk mitigation as well as strategies for moving forward are outlined.

  1. High-density lipoprotein prevents organ damage in endotoxemia.

    PubMed

    Lee, Ru-Ping; Lin, Nien-Tsung; Chao, Yann-Fen Chiou; Lin, Chia-Chin; Harn, Horng-Jyh; Chen, Hsing-I

    2007-06-01

    High-density lipoprotein (HDL) may decrease organ injury in sepsis. This study was designed using an animal model to mimic people who had a high HDL level and to test HDL effects on preventing organ damage in endotoxemia. Endotoxemia was induced by an infusion of lipopolysac-charide (LPS) after HDL or LDL administration. Levels of blood biochemical substances, nitrate/nitrite, and TNF-alpha in sera were measured. Pathological examinations were performed 72 hours after LPS infusion. HDL decreased the endotoxin-induced elevation of AST, ALT, BUN, creatinine, LDH, CPK, nitrate/nitrite, and TNF-alpha. On histological examination, neutrophil infiltration was lower in the HDL group. HDL had a significant effect in preventing endotoxin-induced organ damage. PMID:17514720

  2. Change in composition of high density lipoprotein during gemfibrozil therapy.

    PubMed

    Sorisky, A; Ooi, T C; Simo, I E; Meuffels, M; Hindmarsh, J T; Nair, R

    1987-10-01

    We investigated the high density lipoprotein cholesterol (HDL-C) response in 20 middle-aged males during a 12-week course of gemfibrozil. Three aspects of the increase in HDL-C (25%) were studied and our observations are as follows: (1) subfraction analysis showed that HDL3-C rose earlier and to a larger extent (28%) than HDL2-C (15%), (2) analysis of variance group--time interaction effect and correlation studies of HDL-C and total triglycerides suggest the increase in HDL-C was due to a direct effect of gemfibrozil on HDL metabolism, and (3) HDL-C was the only one of 4 HDL components to increase. Apoprotein A-I (apo A-I) and HDL-phospholipid (HDL-PL) did not change, and HDL-triglyceride (HDL-TG) decreased. This pattern is consistent with a change in composition of HDL, i.e. cholesterol enrichment and triglyceride depletion. PMID:3118893

  3. High Density Electroencephalography in Sleep Research: Potential, Problems, Future Perspective

    PubMed Central

    Lustenberger, Caroline; Huber, Reto

    2012-01-01

    High density EEG (hdEEG) during sleep combines the superior temporal resolution of EEG recordings with high spatial resolution. Thus, this method allows a topographical analysis of sleep EEG activity and thereby fosters the shift from a global view of sleep to a local one. HdEEG allowed to investigate sleep rhythms in terms of their characteristic behavior (e.g., the traveling of slow waves) and in terms of their relationship to cortical functioning (e.g., consciousness and cognitive abilities). Moreover, recent studies successfully demonstrated that hdEEG can be used to study brain functioning in neurological and neuro-developmental disorders, and to evaluate therapeutic approaches. This review highlights the potential, the problems, and future perspective of hdEEG in sleep research. PMID:22593753

  4. Single-Readout High-Density Memristor Crossbar

    NASA Astrophysics Data System (ADS)

    Zidan, M. A.; Omran, H.; Naous, R.; Sultan, A.; Fahmy, H. A. H.; Lu, W. D.; Salama, K. N.

    2016-01-01

    High-density memristor-crossbar architecture is a very promising technology for future computing systems. The simplicity of the gateless-crossbar structure is both its principal advantage and the source of undesired sneak-paths of current. This parasitic current could consume an enormous amount of energy and ruin the readout process. We introduce new adaptive-threshold readout techniques that utilize the locality and hierarchy properties of the computer-memory system to address the sneak-paths problem. The proposed methods require a single memory access per pixel for an array readout. Besides, the memristive crossbar consumes an order of magnitude less power than state-of-the-art readout techniques.

  5. Biominetic High Density Lipoproteins for the Delivery of Therapeutic Oligonucleotides

    NASA Astrophysics Data System (ADS)

    Tripathy, Sushant

    Advances in nanotechnology have brought about novel inorganic and hybrid nanoparticles with unique physico-chemical properties that make them suitable for a broad range of applications---from nano-circuitry to drug delivery. A significant part of those advancements have led to ground-breaking discoveries that have changed the approaches to formulation of therapeutics against diseases, such as cancer. Now-a-days the focus does not lie solely on finding a candidate small-molecule therapeutic with minimal adverse effects, but researchers are looking up to nanoparticles to improve biodistribution and biocompatibility profile of clinically proven therapeutics. The plethora of conjugation chemistries offered by currently extant inorganic nanoparticles have, in recent years, led to great leaps in the field of biomimicry---a modality that promises high biocompatibility. Further, in the pursuit of highly specific therapeutic molecules, researchers have turned to silencing oligonucleotides and some have already brought together the strengths of nanoparticles and silencing oligonucleotides in search of an efficacious therapy for cancer with minimal adverse effects. This dissertation work focuses on such a biomimetic platform---a gold nanoparticle based high density lipoprotein biomimetic (HDL NP), for the delivery of therapeutic oligonucleotides. The first chapter of this body of work introduces the molecular target of the silencing oligonucleotides---VEGFR2, and its role in the progression of solid tumor cancers. The background information also covers important aspects of natural high density lipoproteins (HDL), especially their innate capacity to bind and deliver exogenous and endogenous silencing oligonucleotides to tissues that express their high affinity receptor SRB1. We subsequently describe the synthesis of the biomimetic HDL NP and its oligonucleotide conjugates, and establish their biocompatibility. Further on, experimental data demonstrate the efficacy of silencing

  6. The glass transition in high-density amorphous ice

    PubMed Central

    Loerting, Thomas; Fuentes-Landete, Violeta; Handle, Philip H.; Seidl, Markus; Amann-Winkel, Katrin; Gainaru, Catalin; Böhmer, Roland

    2015-01-01

    There has been a long controversy regarding the glass transition in low-density amorphous ice (LDA). The central question is whether or not it transforms to an ultraviscous liquid state above 136 K at ambient pressure prior to crystallization. Currently, the most widespread interpretation of the experimental findings is in terms of a transformation to a superstrong liquid above 136 K. In the last decade some work has also been devoted to the study of the glass transition in high-density amorphous ice (HDA) which is in the focus of the present review. At ambient pressure HDA is metastable against both ice I and LDA, whereas at > 0.2 GPa HDA is no longer metastable against LDA, but merely against high-pressure forms of crystalline ice. The first experimental observation interpreted as the glass transition of HDA was made using in situ methods by Mishima, who reported a glass transition temperature Tg of 160 K at 0.40 GPa. Soon thereafter Andersson and Inaba reported a much lower glass transition temperature of 122 K at 1.0 GPa. Based on the pressure dependence of HDA's Tg measured in Innsbruck, we suggest that they were in fact probing the distinct glass transition of very high-density amorphous ice (VHDA). Very recently the glass transition in HDA was also observed at ambient pressure at 116 K. That is, LDA and HDA show two distinct glass transitions, clearly separated by about 20 K at ambient pressure. In summary, this suggests that three glass transition lines can be defined in the p–T plane for LDA, HDA, and VHDA. PMID:25641986

  7. Propofol Anesthesia and Sleep: A High-Density EEG Study

    PubMed Central

    Murphy, Michael; Bruno, Marie-Aurelie; Riedner, Brady A.; Boveroux, Pierre; Noirhomme, Quentin; Landsness, Eric C.; Brichant, Jean-Francois; Phillips, Christophe; Massimini, Marcello; Laureys, Steven; Tononi, Giulio; Boly, Melanie

    2011-01-01

    Study Objectives: The electrophysiological correlates of anesthetic sedation remain poorly understood. We used high-density electroencephalography (hd-EEG) and source modeling to investigate the cortical processes underlying propofol anesthesia and compare them to sleep. Design: 256-channel EEG recordings in humans during propofol anesthesia. Setting: Hospital operating room. Patients or Participants: 8 healthy subjects (4 males) Interventions: N/A Measurements and Results: Initially, propofol induced increases in EEG power from 12–25 Hz. Loss of consciousness (LOC) was accompanied by the appearance of EEG slow waves that resembled the slow waves of NREM sleep. We compared slow waves in propofol to slow waves recorded during natural sleep and found that both populations of waves share similar cortical origins and preferentially propagate along the mesial components of the default network. However, propofol slow waves were spatially blurred compared to sleep slow waves and failed to effectively entrain spindle activity. Propofol also caused an increase in gamma (25–40 Hz) power that persisted throughout LOC. Source modeling analysis showed that this increase in gamma power originated from the anterior and posterior cingulate cortices. During LOC, we found increased gamma functional connectivity between these regions compared to the wakefulness. Conclusions: Propofol anesthesia is a sleep-like state and slow waves are associated with diminished consciousness even in the presence of high gamma activity. Citation: Murphy M; Bruno MA; Riedner BA; Boveroux P; Noirhomme Q; Landsness EC; Brichant JF; Phillips C; Massimini M; Laureys S; Tononi G; Boly M. Propofol anesthesia and sleep: a high-density EEG study. SLEEP 2011;34(3):283-291. PMID:21358845

  8. High-density lipoprotein that supports Ureaplasma urealyticum growth.

    PubMed Central

    Sayed, I A; Sweat, F W

    1982-01-01

    A high-density lipoprotein with growth-promoting activity for Ureaplasma urealyticum was purified in high yield from equine serum by ammonium sulfate fractionation and molecular filtration. Fractions enriched in growth-promoting activity represented 5% of the total serum protein, and 30 micrograms of the purified protein per ml gave an activity equivalent to that from 100 micrograms of whole serum per ml. The serum was totally replaced by purified lipoprotein when tested in a soy peptone-yeast dialysate or when added to a chemically defined synthetic medium. Polyacrylamide gel electrophoresis indicated that one major protein with growth-promoting activity is present. A total of 10 proteins were distinguished by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with 75% of the total contributed by two proteins with molecular weights of 160,000 and 170,000. A total of 90% of the lipoprotein was an alpha-protein with a mobility of 0.67 in two-dimensional immunoelectrophoresis (albumin = 1.0). The active component was further characterized as high-density lipoprotein by density ultracentrifugation. Two components with S = 6.4 and S = 15.8 were distinguished by velocity sedimentation. The lipid was removed from lipoprotein during its precipitation with acetone. The growth-promoting activity of delipidized protein was dependent upon the addition of exogenous cholesterol, and [14C]cholesterol was transferred to urea-plasmic cells in cultures containing the delipidized protein. A major portion of the [14C]cholesterol remained associated with the protein during filtration on Sepharose 4B columns. Images PMID:7201468

  9. X-ray lasers and high-density plasma

    SciTech Connect

    1995-03-01

    The improved reliability, high brightness, and short wavelength of x-ray lasers make them ideally suited for studying large, high-density plasmas of interest to the laser-fusion research community. We have been developing the neonlike yttrium x-ray laser as a probe, together with the necessary multilayer mirrors and beam splitters, to image plasmas produced at the Nova laser facility and to measure electron density. With its short-wavelength (15.5-nm) light, we can use the yttrium x-ray laser to probe plasma densities up to 10{sup 23} cm{sup {minus}3}. At the highest magnification (30?), the spatial resolution of our imaging system is better than 1 {mu}m. Using the technique of moire deflectometry, we have measured density gradients of plasmas. Using the technique of interferometry, we have probed 3-mm-long plasmas with electron densities up to 3? 10{sup 21} cm{sup {minus}3}. Temporal blurring of plasma images remains the main limitation of our approach. Thus, we are continuing to improve our theoretical and experimental understanding of laboratory x-ray lasers. We are currently working on techniques to reduce the blurring of images by shortening the x-ray laser pulse to durations approaching about 20 ps. In the future, this important research tool can be applied to study high-density plasmas produced at the proposed National Ignition Facility. Other important applications of the x-ray laser include biological imaging of whole, live cells and other structures at resolutions superior to those obtainable by conventional optical microscopy.

  10. Method for casting polyethylene pipe

    NASA Technical Reports Server (NTRS)

    Elam, R. M., Jr.

    1973-01-01

    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene.

  11. Sensory stability of ultra-high temperature milk in polyethylene bottle.

    PubMed

    Petrus, R R; Walter, E H M; Faria, J A F; Abreu, L F

    2009-01-01

    The objective of this study was to evaluate the sensory stability of ultra-high temperature (UHT) milk subjected to different heat treatments and stored at room temperature in white high density polyethylene bottles (HDPE) pigmented with titanium dioxide. Two lots of 300 units each were processed, respectively, at 135 and 141 degrees C/10 s using indirect heating and subsequently aseptically filled in an ISO class 7 clean room. These experimental lots were evaluated for appearance, aroma, flavor, and overall appreciation and compared to samples of commercial UHT milk purchased from local commercial stores. The time-temperature combinations investigated did not affect either the acceptability or the shelf life of the milk. Despite the limited light barrier properties of HDPE bottles, the product contained in the package tested exhibited good stability, with a shelf life ranging from 4 to 11 wk. Within this time period, the acceptability of the experimental lots was similar to that of the commercial products. The results achieved in this study contribute to turn the low-cost UHT system investigated into a technically viable option for small-size dairy processing plants. PMID:19200121

  12. Thermal analysis of polyethylene + X% carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Lozovyi, Fedir; Ivanenko, Kateryna; Nedilko, Sergii; Revo, Sergiy; Hamamda, Smail

    2016-02-01

    The aim of this research is to study the influence of the multi-walled carbon nanotubes (MWCNTs) on the thermomechanical and structural properties of high-density polyethylene. Several, complementary experimental techniques were used, namely, dilatometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Raman spectroscopy, and infrared (IR) spectroscopy. Dilatometry data showed that nanocomposites exhibit anisotropic behavior, and intensity of the anisotropy depends on the MWCNT concentration. The shapes of the dilatometric curves of the nanocomposites under study differ significantly for the radial and longitudinal directions of the samples. DSC results show that MWCNTs weekly influence calorimetry data, while Raman spectra show that the I D/ I G ratio decreases when MWCNT concentration increases. The IR spectra demonstrate improvement of the crystallinity of the samples as the content in MWCNTs rises.

  13. Method for shaping polyethylene tubing

    NASA Technical Reports Server (NTRS)

    Kramer, R. C.

    1981-01-01

    Method forms polyethylene plastic tubing into configurations previously only possible with metal tubing. By using polyethylene in place of copper or stain less steel tubing inlow pressure systems, fabrication costs are significantly reduced. Polyethylene tubing can be used whenever low pressure tubing is needed in oil operations, aircraft and space applications, powerplants, and testing laboratories.

  14. High-density pulsed laser diode arrays for SSL pumping

    NASA Astrophysics Data System (ADS)

    Feeler, Ryan; Stephens, Edward

    2010-04-01

    Northrop Grumman Cutting Edge Optronics has developed a new laser diode array package with minimal bar-to-bar spacing. These High Density Stack (HDS) packages allow for a power density increase on the order of ~ 2.5x when compared to industry-standard arrays. This work contains an overview of the manufacturing process, as well as representative data for 5-, 10-, and 20-bar arrays. Near-field and power vs. current data is presented in each case. Power densities approaching 15 kW/cm2 are presented. In addition, power and wavelength are presented as a function of pulse width in order to determine the acceptable operational parameters for this type of array. In the low repetition rate Nd:YAG pumping regime, all devices are shown to operate with relatively low junction temperatures. A discussion of future work is also presented, with a focus on extending the HDS architecture to reliable operation at 300W per bar. This will enable power densities of approximately 25 kW/cm2.

  15. A Concept for Robust, High Density Terminal Air Traffic Operations

    NASA Technical Reports Server (NTRS)

    Isaacson, Douglas R.; Robinson, John E.; Swenson, Harry N.; Denery, Dallas G.

    2010-01-01

    This paper describes a concept for future high-density, terminal air traffic operations that has been developed by interpreting the Joint Planning and Development Office s vision for the Next Generation (NextGen) Air Transportation System and coupling it with emergent NASA and other technologies and procedures during the NextGen timeframe. The concept described in this paper includes five core capabilities: 1) Extended Terminal Area Routing, 2) Precision Scheduling Along Routes, 3) Merging and Spacing, 4) Tactical Separation, and 5) Off-Nominal Recovery. Gradual changes are introduced to the National Airspace System (NAS) by phased enhancements to the core capabilities in the form of increased levels of automation and decision support as well as targeted task delegation. NASA will be evaluating these conceptual technological enhancements in a series of human-in-the-loop simulations and will accelerate development of the most promising capabilities in cooperation with the FAA through the Efficient Flows Into Congested Airspace Research Transition Team.

  16. Micro-RNAs and High-Density Lipoprotein Metabolism.

    PubMed

    Canfrán-Duque, Alberto; Lin, Chin-Sheng; Goedeke, Leigh; Suárez, Yajaira; Fernández-Hernando, Carlos

    2016-06-01

    Improved prevention and treatment of cardiovascular diseases is one of the challenges in Western societies, where ischemic heart disease and stroke are the leading cause of death. Early epidemiological studies have shown an inverse correlation between circulating high-density lipoprotein-cholesterol (HDL-C) and cardiovascular diseases. The cardioprotective effect of HDL is because of its ability to remove cholesterol from plaques in the artery wall to the liver for excretion by a process known as reverse cholesterol transport. Numerous studies have reported the role that micro-RNAs (miRNA) play in the regulation of the different steps in reverse cholesterol transport, including HDL biogenesis, cholesterol efflux, and cholesterol uptake in the liver and bile acid synthesis and secretion. Because of their ability to control different aspects of HDL metabolism and function, miRNAs have emerged as potential therapeutic targets to combat cardiovascular diseases. In this review, we summarize the recent advances in the miRNA-mediated control of HDL metabolism. We also discuss how HDL particles serve as carriers of miRNAs and the potential use of HDL-containing miRNAs as cardiovascular diseases biomarkers. PMID:27079881

  17. High-Density Superconducting Cables for Advanced ACTPol

    NASA Astrophysics Data System (ADS)

    Pappas, C. G.; Austermann, J.; Beall, J. A.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Henderson, S. W.; Ho, S. P.; Koopman, B. J.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-01-01

    Advanced ACTPol (AdvACT) is an upcoming Atacama Cosmology Telescope (ACT) receiver upgrade, scheduled to deploy in 2016, that will allow measurement of the cosmic microwave background polarization and temperature to the highest precision yet with ACT. The AdvACT increase in sensitivity is partly provided by an increase in the number of transition-edge sensors (TESes) per array by up to a factor of two over the current ACTPol receiver detector arrays. The high-density AdvACT TES arrays require 70 \\upmu m pitch superconducting flexible cables (flex) to connect the detector wafer to the first-stage readout electronics. Here, we present the flex fabrication process and test results. For the flex wiring layer, we use a 400-nm-thick sputtered aluminum film. In the center of the cable, the wiring is supported by a polyimide substrate, which smoothly transitions to a bare (uncoated with polyimide) silicon substrate at the ends of the cable for a robust wedge wire-bonding interface. Tests on the first batch of flex made for the first AdvACT array show that the flex will meet the requirements for AdvACT, with a superconducting critical current above 1 mA at 500 mK, resilience to mechanical and cryogenic stress, and a room temperature yield of 97 %.

  18. Mixed Nitrogen-Methane Solids at High Density

    NASA Astrophysics Data System (ADS)

    Desgreniers, Serge

    Mixing different molecular species may yield weakly bound compounds or van der Waals solids upon the application of high pressure. Van der Waals solids differ in physical properties from solids formed by pure molecular species at comparable thermodynamic conditions. In this contribution, we present results of the formation of binary methane-nitrogen compounds at high density. Methane and nitrogen, with similar potentials and molecular size, are expected to be partly miscible in the condensed state. Using single crystal and powder X-ray diffraction with synchrotron radiation and vibrational spectroscopy, the pressure-concentration phase diagram for this system has been explored from 1 to 16 GPa, at room temperature. The existence of van der Waals solid phases for samples with concentrations above 10% (methane per volume) is demonstrated. For example, at 7.6 GPa and at room temperature, whereas pure nitrogen and methane exist in cubic and in rhombohedral structures, respectively, our study indicates that a methane-nitrogen sample with 60% nitrogen by volume exhibits, under the same conditions, a novel phase with a tetragonal symmetry. Other novel structures in methane-nitrogen samples with different concentrations under varying pressure conditions have also been observed and will be discussed.

  19. Atomistic Simulation of High-Density Uranium Fuels

    DOE PAGESBeta

    Garcés, Jorge Eduardo; Bozzolo, Guillermo

    2011-01-01

    We apply an atomistic modeling approach to deal with interfacial phenomena in high-density uranium fuels. The effects of Si, as additive to Al or as U-Mo-particles coating, on the behavior of the Al/U-Mo interface is modeled by using the Bozzolo-Ferrante-Smith (BFS) method for alloys. The basic experimental features characterizing the real system are identified, via simulations and atom-by-atom analysis. These include (1) the trend indicating formation of interfacial compounds, (2) much reduced diffusion of Al into U-Mo solid solution due to the high Si concentration, (3) Si depletion in the Al matrix, (4) an unexpected interaction between Mo and Simore » which inhibits Si diffusion to deeper layers in the U-Mo solid solution, and (5) the minimum amount of Si needed to perform as an effective diffusion barrier. Simulation results related to alternatives to Si dispersed in the Al matrix, such as the use of C coating of U-Mo particles or Zr instead of the Al matrix, are also shown. Recent experimental results confirmed early theoretical proposals, along the lines of the results reported in this work, showing that atomistic computational modeling could become a valuable tool to aid the experimental work in the development of nuclear fuels.« less

  20. High Density Lipoprotein Cholesterol Increasing Therapy: The Unmet Cardiovascular Need

    PubMed Central

    Cimmino, Giovanni; Ciccarelli, Giovanni; Morello, Alberto; Ciccarelli, Michele; Golino, Paolo

    2015-01-01

    Despite aggressive strategies are now available to reduce LDL-cholesterol, the risk of cardiovascular events in patients with coronary artery disease remains substantial. Several preclinical and clinical studies have shown that drug therapy ultimately leads to a regression of the angiographic lesions but also results in a reduction in cardiovascular events. The dramatic failure of clinical trials evaluating the cholesterol ester transfer protein (CEPT) inhibitors, torcetrapib and dalcetrapib, has led to considerable doubt about the value of the current strategy to raise high-density lipoprotein cholesterol (HDL-C) as a treatment for cardiovascular disease. These clinical results, as well as animal studies, have revealed the complexity of HDL metabolism, assessing a more important role of functional quality compared to circulating quantity of HDL. As a result, HDL-based therapeutic interventions that maintain or enhance HDL functionality, such as improving its main property, the reverse cholesterol transport, require closer investigation. In this review, we will discuss HDL metabolism and function, clinical-trial data available for HDL-raising agents, and potential strategies for future HDL-based therapies. PMID:26535185

  1. Ethanol enhances de novo synthesis of high density lipoprotein cholesterol

    SciTech Connect

    Cluette, J.E.; Mulligan, J.J.; Noring, R.; Doyle, K.; Hojnacki, J.

    1984-05-01

    Male squirrel monkeys fed ethanol at variable doses were used to assess whether alcohol enhances de novo synthesis of high density lipoprotein (HDL) cholesterol in vivo. Monkeys were divided into three groups: 1) controls fed isocaloric liquid diet; 2) low ethanol monkeys fed liquid diet with vodka substituted isocalorically for carbohydrate at 12% of calories; and 3) High Ethanol animals fed diet plus vodka at 24% of calories. High Ethanol primates had significantly higher levels of HDL nonesterified cholesterol than Control and Low Ethanol animals while serum glutamate oxaloacetate transaminase was similar for the three treatments. There were no significant differences between the groups in HDL cholesteryl ester mass or specific activity following intravenous injection of labeled mevalonolactone. By contrast, High Ethanol monkeys had significantly greater HDL nonesterified cholesterol specific activity with approximately 60% of the radioactivity distributed in the HDL/sub 3/ subfraction. This report provides the first experimental evidence that ethanol at 24% of calories induces elevations in HDL cholesterol in primates through enhanced de novo synthesis without adverse effects on liver function.

  2. Benchmarking High Density Image Matching for Oblique Airborne Imagery

    NASA Astrophysics Data System (ADS)

    Cavegn, S.; Haala, N.; Nebiker, S.; Rothermel, M.; Tutzauer, P.

    2014-08-01

    Both, improvements in camera technology and new pixel-wise matching approaches triggered the further development of software tools for image based 3D reconstruction. Meanwhile research groups as well as commercial vendors provide photogrammetric software to generate dense, reliable and accurate 3D point clouds and Digital Surface Models (DSM) from highly overlapping aerial images. In order to evaluate the potential of these algorithms in view of the ongoing software developments, a suitable test bed is provided by the ISPRS/EuroSDR initiative Benchmark on High Density Image Matching for DSM Computation. This paper discusses the proposed test scenario to investigate the potential of dense matching approaches for 3D data capture from oblique airborne imagery. For this purpose, an oblique aerial image block captured at a GSD of 6 cm in the west of Zürich by a Leica RCD30 Oblique Penta camera is used. Within this paper, the potential test scenario is demonstrated using matching results from two software packages, Agisoft PhotoScan and SURE from University of Stuttgart. As oblique images are frequently used for data capture at building facades, 3D point clouds are mainly investigated at such areas. Reference data from terrestrial laser scanning is used to evaluate data quality from dense image matching for several facade patches with respect to accuracy, density and reliability.

  3. Acrolein Impairs the Cholesterol Transport Functions of High Density Lipoproteins

    PubMed Central

    Chadwick, Alexandra C.; Holme, Rebecca L.; Chen, Yiliang; Thomas, Michael J.; Sorci-Thomas, Mary G.; Silverstein, Roy L.; Pritchard, Kirkwood A.; Sahoo, Daisy

    2015-01-01

    High density lipoproteins (HDL) are considered athero-protective, primarily due to their role in reverse cholesterol transport, where they transport cholesterol from peripheral tissues to the liver for excretion. The current study was designed to determine the impact of HDL modification by acrolein, a highly reactive aldehyde found in high abundance in cigarette smoke, on the cholesterol transport functions of HDL. HDL was chemically-modified with acrolein and immunoblot and mass spectrometry analyses confirmed apolipoprotein crosslinking, as well as acrolein adducts on apolipoproteins A-I and A-II. The ability of acrolein-modified HDL (acro-HDL) to serve as an acceptor of free cholesterol (FC) from COS-7 cells transiently expressing SR-BI was significantly decreased. Further, in contrast to native HDL, acro-HDL promotes higher neutral lipid accumulation in murine macrophages as judged by Oil Red O staining. The ability of acro-HDL to mediate efficient selective uptake of HDL-cholesteryl esters (CE) into SR-BI-expressing cells was reduced compared to native HDL. Together, the findings from our studies suggest that acrolein modification of HDL produces a dysfunctional particle that may ultimately promote atherogenesis by impairing functions that are critical in the reverse cholesterol transport pathway. PMID:25849485

  4. In vivo protection against endotoxin by plasma high density lipoprotein.

    PubMed Central

    Levine, D M; Parker, T S; Donnelly, T M; Walsh, A; Rubin, A L

    1993-01-01

    Overwhelming bacterial infection is accompanied by fever, hypotension, disseminated intravascular coagulation, and multiple organ failure leading to death in 30-80% of cases. These classical symptoms of septic shock are caused by potent cytokines that are produced in response to endotoxin released from Gram-negative bacteria. Treatments with antibodies and receptor antagonists to block endotoxin or cytokine mediators have given mixed results in clinical trials. High density lipoprotein (HDL) is a natural component of plasma that is known to neutralize endotoxin in vitro. We report here that raising the plasma HDL concentration protects mice against endotoxin in vivo. Transgenic mice with 2-fold-elevated plasma HDL levels had more endotoxin bound to HDL, lower plasma cytokine levels, and improved survival rates compared with low-HDL mice. Intravenous infusion of HDL also protected mice, but only when given as reconstituted HDL prepared from phospholipid and either HDL apoprotein or an 18-amino acid peptide synthesized to mimic the structure of apolipoprotein A-I of HDL. Intact plasma HDL was mildly toxic, and HDL apoprotein was ineffective. The effectiveness of the reconstituted peptide renders very unlikely any significant contribution to protection by trace proteins in apo-HDL. These data suggest a simple leaflet insertion model for binding and neutralization of lipopolysaccharide by phospholipid on the surface of HDL. Plasma HDL may normally act to protect against endotoxin; this protection may be augmented by administration of reconstituted HDL or reconstituted peptides. Images Fig. 1 Fig. 2 Fig. 3 PMID:8265667

  5. Structural stability and functional remodeling of high-density lipoproteins.

    PubMed

    Gursky, Olga

    2015-09-14

    Lipoproteins are protein-lipid nanoparticles that transport lipids in circulation and are central in atherosclerosis and other disorders of lipid metabolism. Apolipoproteins form flexible structural scaffolds and important functional ligands on the particle surface and direct lipoprotein metabolism. Lipoproteins undergo multiple rounds of metabolic remodeling that is crucial to lipid transport. Important aspects of this remodeling, including apolipoprotein dissociation and particle fusion, are mimicked in thermal or chemical denaturation and are modulated by free energy barriers. Here we review the biophysical studies that revealed the kinetic mechanism of lipoprotein stabilization and unraveled its structural basis. The main focus is on high-density lipoprotein (HDL). An inverse correlation between stability and functions of various HDLs in cholesterol transport suggests the functional role of structural disorder. A mechanism for the conformational adaptation of the major HDL proteins, apoA-I and apoA-II, to the increasing lipid load is proposed. Together, these studies help understand why HDL forms discrete subclasses separated by kinetic barriers, which have distinct composition, conformation and functional properties. Understanding these properties may help improve HDL quality and develop novel therapies for cardiovascular disease. PMID:25749369

  6. High-density lipoprotein: a novel target for antirestenosis therapy.

    PubMed

    Yin, Kai; Agrawal, Devendra K

    2014-12-01

    Restenosis is an integral pathological process central to the recurrent vessel narrowing after interventional procedures. Although the mechanisms for restenosis are diverse in different pathological conditions, endothelial dysfunction, inflammation, vascular smooth muscle cell (SMC) proliferation, and myofibroblasts transition have been thought to play crucial role in the development of restenosis. Indeed, there is an inverse relationship between high-density lipoprotein (HDL) levels and risk for coronary heart disease (CHD). However, relatively studies on the direct assessment of HDL effect on restenosis are limited. In addition to involvement in the cholesterol reverse transport, many vascular protective effects of HDL, including protection of endothelium, antiinflammation, antithrombus actions, inhibition of SMC proliferation, and regulation by adventitial effects may contribute to the inhibition of restenosis, though the exact relationships between HDL and restenosis remain to be elucidated. This review summarizes the vascular protective effects of HDL, emphasizing the potential role of HDL in intimal hyperplasia and vascular remodeling, which may provide novel prophylactic and therapeutic strategies for antirestenosis. PMID:25043950

  7. High-Density Lipoprotein, Lecithin: Cholesterol Acyltransferase, and Atherosclerosis

    PubMed Central

    Ossoli, Alice; Pavanello, Chiara

    2016-01-01

    Epidemiological data clearly show the existence of a strong inverse correlation between plasma high-density lipoprotein cholesterol (HDL-C) concentrations and the incidence of coronary heart disease. This relation is explained by a number of atheroprotective properties of HDL, first of all the ability to promote macrophage cholesterol transport. HDL are highly heterogeneous and are continuously remodeled in plasma thanks to the action of a number of proteins and enzymes. Among them, lecithin:cholesterol acyltransferase (LCAT) plays a crucial role, being the only enzyme able to esterify cholesterol within lipoproteins. LCAT is synthetized by the liver and it has been thought to play a major role in reverse cholesterol transport and in atheroprotection. However, data from animal studies, as well as human studies, have shown contradictory results. Increased LCAT concentrations are associated with increased HDL-C levels but not necessarily with atheroprotection. On the other side, decreased LCAT concentration and activity are associated with decreased HDL-C levels but not with increased atherosclerosis. These contradictory results confirm that HDL-C levels per se do not represent the functionality of the HDL system. PMID:27302716

  8. High-Density Lipoprotein, Lecithin: Cholesterol Acyltransferase, and Atherosclerosis.

    PubMed

    Ossoli, Alice; Pavanello, Chiara; Calabresi, Laura

    2016-06-01

    Epidemiological data clearly show the existence of a strong inverse correlation between plasma high-density lipoprotein cholesterol (HDL-C) concentrations and the incidence of coronary heart disease. This relation is explained by a number of atheroprotective properties of HDL, first of all the ability to promote macrophage cholesterol transport. HDL are highly heterogeneous and are continuously remodeled in plasma thanks to the action of a number of proteins and enzymes. Among them, lecithin:cholesterol acyltransferase (LCAT) plays a crucial role, being the only enzyme able to esterify cholesterol within lipoproteins. LCAT is synthetized by the liver and it has been thought to play a major role in reverse cholesterol transport and in atheroprotection. However, data from animal studies, as well as human studies, have shown contradictory results. Increased LCAT concentrations are associated with increased HDL-C levels but not necessarily with atheroprotection. On the other side, decreased LCAT concentration and activity are associated with decreased HDL-C levels but not with increased atherosclerosis. These contradictory results confirm that HDL-C levels per se do not represent the functionality of the HDL system. PMID:27302716

  9. Irradiation testing of high density uranium alloy dispersion fuels

    SciTech Connect

    Hayes, S.L.; Trybus, C.L.; Meyer, M.K.

    1997-10-01

    Two irradiation test vehicles have been designed, fabricated, and inserted into the Advanced Test Reactor in Idaho. Irradiation of these experiments began in August 1997. These irradiation tests were designed to obtain irradiation performance information on a variety of potential new, high-density dispersion fuels. Each of the two irradiation vehicles contains 32 microplates. Each microplate is aluminum clad, having an aluminum matrix phase and containing one of the following compositions as the fuel phase: U-10Mo, U-8Mo, U-6Mo, U-4Mo, U-9Nb-3Zr, U-6Nb-4Zr, U-5Nb-3Zr, U-6Mo-1Pt, U-6Mo-0.6Ru, U-10Mo-0.05Sn, U{sub 2}Mo, or U{sub 3}Si{sub 2}. These experiments will be discharged at peak fuel burnups of 40% and 80%. Of particular interest is the fission gas retention/swelling characteristics of these new fuel alloys. This paper presents the design of the irradiation vehicles and the irradiation conditions.

  10. Enhanced configurational entropy in high-density nanoconfined bilayer ice

    NASA Astrophysics Data System (ADS)

    Corsetti, Fabiano; Zubeltzu, Jon; Artacho, Emilio

    Understanding the structural tendencies of nanoconfined water is of great interest for nanoscience and biology, where nano/micro-sized objects may be separated by very few layers of water. We present a study of water confined to a 2D geometry by a featureless, chemically neutral potential, in order to characterize its intrinsic behaviour. We use molecular dynamics simulations with the TIP4P/2005 potential, combined with density-functional theory calculations with a non-local van der Waals density functional and an ab initio random structure search procedure. We propose a novel kind of crystal order in high-density nanoconfined bilayer ice. A first-order transition is observed between a low-temperature proton-ordered solid and a high-temperature proton-disordered solid. The latter is shown to possess crystalline order for the oxygen positions, arranged on a close-packed triangular lattice with AA stacking. Uniquely amongst the ice phases, the triangular bilayer is characterized by two levels of disorder (for the bonding network and for the protons) which results in a configurational entropy twice that of bulk ice.

  11. High-Density Infrared Surface Treatments of Refractories

    SciTech Connect

    Tiegs, T.N.

    2005-03-31

    Refractory materials play a crucial role in all energy-intensive industries and are truly a crosscutting technology for the Industries of the Future (IOF). One of the major mechanisms for the degradation of refractories and a general decrease in their performance has been the penetration and corrosion by molten metals or glass. Methods and materials that would reduce the penetration, wetting, and corrosive chemistry would significantly improve refractory performance and also maintain the quality of the processed liquid, be it metal or glass. This report presents the results of an R&D project aimed at investigating the use of high-density infrared (HDI) heating to surface treat refractories to improve their performance. The project was a joint effort between Oak Ridge National Laboratory (ORNL) and the University of Missouri-Rolla (UMR). HDI is capable of heating the near-surface region of materials to very high temperatures where sintering, diffusion, and melting can occur. The intended benefits of HDI processing of refractories were to (1) reduce surface porosity (by essentially sealing the surface to prevent liquid penetration), (2) allow surface chemistry changes to be performed by bonding an adherent coating onto the underlying refractory (in order to inhibit wetting and/or improve corrosion resistance), and (3) produce noncontact refractories with high-emissivity surface coatings.

  12. High density operation with Lower Hybrid waves in FTU tokamak

    NASA Astrophysics Data System (ADS)

    Pericoli Ridolfini, V.; Mirizzi, F.; Panaccione, L.; Podda, S.

    2001-10-01

    Since April 2001 the lower hybrid (LH) radiofrequency system in FTU (6 gyrotrons @ f=8 GHz) can deliver to the plasma about 2 MW through two equal launchers with a reflection coefficient = 10%. This value is close to the target value of 2.2 MW (net power density of 6.2 kW/cm2 on the waveguides mouth) which could be reached after further conditioning of the grill and of the transmission lines. In high density plasmas (line density *1*1020 m-3), high magnetic field (BT=7.2 T), with PLH=2 MW we drive about 75% of the total current (Ip=500 kA) and stabilise fully the sawteeth activity. The central electron temperature Te0 increases from 1.6 to 3.3 keV (steady), and the neutron rate by about 10 times. Analysis of these pulses with effective electronic heating will be presented. In post-pellet plasmas ( *6*1020 m-3), good coupling of the LH is achieved with the launcher almost flush to the walls, due to the very dense scrape off-layer. The perturbation here induced by the pellet imposes a delay to the LH of only 20 ms. The exact location of the launcher is critical in these regimes, because the high N|| (parallel index of refraction) requested (N||>2.3) for a good penetration of the waves makes more problematic a good coupling all along the poloidal extension of the grill.

  13. High-density lipoprotein endocytosis in endothelial cells

    PubMed Central

    Fruhwürth, Stefanie; Pavelka, Margit; Bittman, Robert; Kovacs, Werner J; Walter, Katharina M; Röhrl, Clemens; Stangl, Herbert

    2013-01-01

    AIM: To describe the way stations of high-density lipoprotein (HDL) uptake and its lipid exchange in endothelial cells in vitro and in vivo. METHODS: A combination of fluorescence microscopy using novel fluorescent cholesterol surrogates and electron microscopy was used to analyze HDL endocytosis in great detail in primary human endothelial cells. Further, HDL uptake was quantified using radio-labeled HDL particles. To validate the in vitro findings mice were injected with fluorescently labeled HDL and particle uptake in the liver was analyzed using fluorescence microscopy. RESULTS: HDL uptake occurred via clathrin-coated pits, tubular endosomes and multivesicular bodies in human umbilical vein endothelial cells. During uptake and resecretion, HDL-derived cholesterol was exchanged at a faster rate than cholesteryl oleate, resembling the HDL particle pathway seen in hepatic cells. In addition, lysosomes were not involved in this process and thus HDL degradation was not detectable. In vivo, we found HDL mainly localized in mouse hepatic endothelial cells. HDL was not detected in parenchymal liver cells, indicating that lipid transfer from HDL to hepatocytes occurs primarily via scavenger receptor, class B, type I mediated selective uptake without concomitant HDL endocytosis. CONCLUSION: HDL endocytosis occurs via clathrin-coated pits, tubular endosomes and multivesicular bodies in human endothelial cells. Mouse endothelial cells showed a similar HDL uptake pattern in vivo indicating that the endothelium is one major site of HDL endocytosis and transcytosis. PMID:24340136

  14. Evolutionary sequence comparisons using high-density oligonucleotide arrays.

    PubMed

    Hacia, J G; Makalowski, W; Edgemon, K; Erdos, M R; Robbins, C M; Fodor, S P; Brody, L C; Collins, F S

    1998-02-01

    We explored the utility of high-density oligonucleotide arrays (DNA chips) for obtaining sequence information from homologous genes in closely related species. Orthologues of the human BRCA1 exon 11, all approximately 3.4 kb in length and ranging from 98.2% to 83.5% nucleotide identity, were subjected to hybridization-based and conventional dideoxysequencing analysis. Retrospective guidelines for identifying high-fidelity hybridization-based sequence calls were formulated based upon dideoxysequencing results. Prospective application of these rules yielded base-calling with at least 98.8% accuracy over orthologous sequence tracts shown to have approximately 99% identity. For higher primate sequences with greater than 97% nucleotide identity, base-calling was made with at least 99.91% accuracy covering a minimum of 97% of the sequence. Using a second-tier confirmatory hybridization chip strategy, shown in several cases to confirm the identity of predicted sequence changes, the complete sequence of the chimpanzee, gorilla and orangutan orthologues should be deducible solely through hybridization-based methodologies. Analysis of less highly conserved orthologues can still identify conserved nucleotide tracts of at least 15 nucleotides and can provide useful information for designing primers. DNA-chip based assays can be a valuable new technology for obtaining high-throughput cost-effective sequence information from related genomes. PMID:9462745

  15. High-density lipoprotein and inflammation in cardiovascular disease.

    PubMed

    Connelly, Margery A; Shalaurova, Irina; Otvos, James D

    2016-07-01

    Great advances are being made at the mechanistic level in the understanding of the structural and functional diversity of high-density lipoprotein (HDL). HDL particle subspecies of different sizes are now known to differ in the protein and lipid cargo they transport, conferring on them the ability to perform different functions that in aggregate would be expected to provide protection against the development of atherosclerosis and its downstream clinical consequences. Exacerbating what is already a very complex system is the finding that inflammation, via alteration of the proteomic and lipidomic composition of HDL subspecies, can modulate at least some of their functional activities. In contrast to the progress being made at the mechanistic level, HDL epidemiologic research has lagged behind, largely because the simple HDL biomarkers used (mainly just HDL cholesterol) lack the needed complexity. To address this deficiency, analyses will need to use multiple HDL subspecies and be conducted in such a way as to eliminate potential sources of confounding. To help account for the modulating influence of inflammation, effective use must also be made of inflammatory biomarkers including searching systematically for HDL-inflammation interactions. Using nuclear magnetic resonance (NMR)-measured HDL subclass data and a novel NMR-derived inflammatory biomarker, GlycA, we offer a case study example of the type of analytic approach considered necessary to advance HDL epidemiologic understanding. PMID:26850902

  16. Characterizing uncertainty in high-density maps from multiparental populations.

    PubMed

    Ahfock, Daniel; Wood, Ian; Stephen, Stuart; Cavanagh, Colin R; Huang, B Emma

    2014-09-01

    Multiparental populations are of considerable interest in high-density genetic mapping due to their increased levels of polymorphism and recombination relative to biparental populations. However, errors in map construction can have significant impact on QTL discovery in later stages of analysis, and few methods have been developed to quantify the uncertainty attached to the reported order of markers or intermarker distances. Current methods are computationally intensive or limited to assessing uncertainty only for order or distance, but not both simultaneously. We derive the asymptotic joint distribution of maximum composite likelihood estimators for intermarker distances. This approach allows us to construct hypothesis tests and confidence intervals for simultaneously assessing marker-order instability and distance uncertainty. We investigate the effects of marker density, population size, and founder distribution patterns on map confidence in multiparental populations through simulations. Using these data, we provide guidelines on sample sizes necessary to map markers at sub-centimorgan densities with high certainty. We apply these approaches to data from a bread wheat Multiparent Advanced Generation Inter-Cross (MAGIC) population genotyped using the Illumina 9K SNP chip to assess regions of uncertainty and validate them against the recently released pseudomolecule for the wheat chromosome 3B. PMID:25236453

  17. [Residual risk: The roles of triglycerides and high density lipoproteins].

    PubMed

    Grammer, Tanja; Kleber, Marcus; Silbernagel, Günther; Scharnagl, Hubert; März, Winfried

    2016-06-01

    In clinical trials, the reduction of LDL-cholesterol (LDL-C) with statins reduces the incidence rate of cardiovascular events by approximately one third. This means, that a sizeable "residual risk" remains. Besides high lipoprotein (a), disorders in the metabolism of triglyceride-rich lipoproteins and high density liproteins have been implicated as effectors of the residual risk. Both lipoprotein parameters correlate inversely with each other. Therefore, the etiological contributions of triglycerides and / or of HDL for developing cardiovascular disease can hardly be estimated from either observational studies or from intervention studies. The largely disappointing results of intervention studies with inhibitors of the cholesteryl ester transfer protein and in particular the available set of genetically-epidemiological studies suggest that in the last decade, the importance of HDL cholesterol has been overvalued, while the importance of triglycerides has been underestimated. High triglycerides not always atherogenic, but only if they are associated with the accumulation relatively cholesterol-enriched, incompletely catabolized remnants of chylomicrons and very low density lipoproteins (familial type III hyperlipidemia, metabolic syndrome, diabetes mellitus). The normalization of the concentration of triglycerides and remnants by inhibiting the expression of apolipoprotein C3 is hence a new, promising therapeutic target. PMID:27305303

  18. Characterizing Uncertainty in High-Density Maps from Multiparental Populations

    PubMed Central

    Ahfock, Daniel; Wood, Ian; Stephen, Stuart; Cavanagh, Colin R.

    2014-01-01

    Multiparental populations are of considerable interest in high-density genetic mapping due to their increased levels of polymorphism and recombination relative to biparental populations. However, errors in map construction can have significant impact on QTL discovery in later stages of analysis, and few methods have been developed to quantify the uncertainty attached to the reported order of markers or intermarker distances. Current methods are computationally intensive or limited to assessing uncertainty only for order or distance, but not both simultaneously. We derive the asymptotic joint distribution of maximum composite likelihood estimators for intermarker distances. This approach allows us to construct hypothesis tests and confidence intervals for simultaneously assessing marker-order instability and distance uncertainty. We investigate the effects of marker density, population size, and founder distribution patterns on map confidence in multiparental populations through simulations. Using these data, we provide guidelines on sample sizes necessary to map markers at sub-centimorgan densities with high certainty. We apply these approaches to data from a bread wheat Multiparent Advanced Generation Inter-Cross (MAGIC) population genotyped using the Illumina 9K SNP chip to assess regions of uncertainty and validate them against the recently released pseudomolecule for the wheat chromosome 3B. PMID:25236453

  19. Evaluation of High Density Algal Cultivation for Secondary Wastewater Polishing.

    PubMed

    Xu, Meng; Xu, Shengnan; Bernards, Matthew; Hu, Zhiqiang

    2016-01-01

    This study evaluated the performance of an algal membrane bioreactor (A-MBR) for secondary wastewater effluent polishing and determined the membrane fouling behavior and dominance of algae in the A-MBR. The continuous flow A-MBR (effective volume = 7.2 L) was operated with low biomass wastage for more than 180 days, resulting in an average algal mixed liquor suspended solid concentration of 4922 mg/L. At the influent concentrations of 43 mg/L COD, 1.6 mg/L total phosphorus (TP), and 11.8 mg/L total nitrogen (TN), the effluent COD, TP and TN concentrations were 26 ± 6 mg/L, 0.7 ± 0.3 mg/L, and 9.6 ± 1.2 mg/L, respectively. High-density algae cultivation facilitated P adsorption and chemical precipitation. However, the TN removal efficiency was only 14% because of low biomass wastage. Although bacteria represented less than 2% of the total biomass in the A-MBR, bacterial growth in the secondary wastewater effluent accelerated membrane fouling. PMID:26803026

  20. High-Density Superconducting Cables for Advanced ACTPol

    NASA Astrophysics Data System (ADS)

    Pappas, C. G.; Austermann, J.; Beall, J. A.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Henderson, S. W.; Ho, S. P.; Koopman, B. J.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-07-01

    Advanced ACTPol (AdvACT) is an upcoming Atacama Cosmology Telescope (ACT) receiver upgrade, scheduled to deploy in 2016, that will allow measurement of the cosmic microwave background polarization and temperature to the highest precision yet with ACT. The AdvACT increase in sensitivity is partly provided by an increase in the number of transition-edge sensors (TESes) per array by up to a factor of two over the current ACTPol receiver detector arrays. The high-density AdvACT TES arrays require 70 \\upmu m pitch superconducting flexible cables (flex) to connect the detector wafer to the first-stage readout electronics. Here, we present the flex fabrication process and test results. For the flex wiring layer, we use a 400-nm-thick sputtered aluminum film. In the center of the cable, the wiring is supported by a polyimide substrate, which smoothly transitions to a bare (uncoated with polyimide) silicon substrate at the ends of the cable for a robust wedge wire-bonding interface. Tests on the first batch of flex made for the first AdvACT array show that the flex will meet the requirements for AdvACT, with a superconducting critical current above 1 mA at 500 mK, resilience to mechanical and cryogenic stress, and a room temperature yield of 97 %.

  1. Anti-Viral Antibody Profiling by High Density Protein Arrays

    PubMed Central

    Bian, Xiaofang; Wiktor, Peter; Kahn, Peter; Brunner, Al; Khela, Amritpal; Karthikeyan, Kailash; Barker, Kristi; Yu, Xiaobo; Magee, Mitch; Wasserfall, Clive H.; Gibson, David; Rooney, Madeleine E; Qiu, Ji; LaBaer, Joshua

    2015-01-01

    Viral infections elicit anti-viral antibodies and have been associated with various chronic diseases. Detection of these antibodies can facilitate diagnosis, treatment of infection and understanding of the mechanisms of virus associated diseases. In this work, we assayed anti-viral antibodies using a novel high density-nucleic acid programmable protein array (HD-NAPPA) platform. Individual viral proteins were expressed in situ directly from plasmids encoding proteins in an array of microscopic reaction chambers. Quality of protein display and serum response was assured by comparing intra- and inter- array correlation within or between printing batches with average correlation coefficients of 0.91 and 0.96, respectively. HD-NAPPA showed higher signal to background (S/B) ratio compared with standard NAPPA on planar glass slides and ELISA. Antibody responses to 761 antigens from 25 different viruses were profiled among patients with juvenile idiopathic arthritis (JIA) and type 1 diabetes (T1D). Common as well as unique antibody reactivity patterns were detected between patients and healthy controls. We believe HD-viral-NAPPA will enable the study of host-pathogen interactions at unprecedented dimensions and elucidate the role of pathogen infections in disease development. PMID:25758251

  2. High-Density Peptide Arrays for Malaria Vaccine Development.

    PubMed

    Loeffler, Felix F; Pfeil, Johannes; Heiss, Kirsten

    2016-01-01

    The development of an efficacious and practicable vaccine conferring sterile immunity towards a Plasmodium infection represents a not yet achieved goal. A crucial factor for the impact of a given anti-plasmodial subunit vaccine is the identification of the most potent parasitic components required to induce protection from both infection and disease. Here, we present a method based on a novel high-density peptide array technology that allows for a flexible readout of malaria antibodies. Peptide arrays applied as a screening method can be used to identify novel immunogenic antibody epitopes under a large number of potential antigens/peptides. Ultimately, discovered antigen candidates and/or epitope sequences can be translated into vaccine prototype design. The technology can be further utilized to unravel antibody-mediated immune responses (e.g., involved in the establishment of semi-immunity) and moreover to confirm vaccine potency during the process of clinical development by verifying the induced antibody responses following vaccination. PMID:27076154

  3. High-density matter: current status and future challenges

    NASA Astrophysics Data System (ADS)

    Stone, J. R.

    2015-05-01

    There are many fascinating processes in the Universe which we observe in more and more in detail thanks to increasingly sophisticated technology. One of the most interesting phenomena is the life cycle of stars, their birth, evolution and death. If the stars are massive enough, they end their lives in the core-collapse supernova explosion, the one of the most violent events in the Universe. As the result, the densest objects in the Universe, neutron stars and/or black holes are created. Naturally, the physical basis of these events should be understood in line with observation. The current status of our knowledge of processes in the life of stars is far from adequate for their true understanding. We show that although many models have been constructed their detailed ability to describe observations is limited or non-existent. Furthermore the general failure of all models means that we cannot tell which are heading in the right direction. A possible way forward in modeling of high-density matter is outlined, exemplified by the quark-meson-coupling model (QMC). This model has a natural explanation for the saturation of nuclear forces and depends on very few adjustable parameters, strongly constrained by the underlying physics. Latest QMC results for compact objects and finite nuclei are presented.

  4. Effect of seawater environmental exposure on fatigue properties of polyethylene pipe

    SciTech Connect

    Tipton, D G

    1980-10-01

    One laboratory study at NIT was reported to show an unexpected decrease in crystallinity for a polyethylene material exposed to fatigue loading in a synthetic seawater solution. High density polyethylene Sclairpipe, from the OTEC-1 cold water pipe, was evaluated for resistance to corrosion fatigue in natural seawater. Intermediate crystallinity measurements (via bulk density) showed no effect of corrosion fatigue exposure. Heat of fusion (a relative indicator of crystallinity) also showed no effect of the exposure. Seawater exposure produced no significant change in tensile strength. One failure was observed during the corrosion fatigue tests and was attributed to porosity observed by fractography. These data suggest that high density polyethylene is not significantly sensitive to degradation of fatigue strength in natural seawater.

  5. Polymer-coated pH-responsive high-density lipoproteins.

    PubMed

    Kim, Hyungjin; Okamoto, Haruki; Felber, Arnaud E; Polomska, Anna; Morone, Nobuhiro; Heuser, John E; Leroux, Jean-Christophe; Murakami, Tatsuya

    2016-04-28

    Intracellular drug delivery by nanoparticles is often hampered by their endosomal entrapment followed by their degradation in the lysosomal compartment and/or exocytosis. Here, we show that internalization and endosomal escape of cargoes in a cationized natural nanocarrier, high-density lipoprotein (HDL), can be controlled in a pH-dependent manner through stable complexation with a membranolytic anionic block polymer. A genetically and chemically cationized form of HDL (catHDL) is prepared for the first time by both genetic fusion with YGRKKRRQRRR peptide and incorporation of 1,2-dioleoyloxy-3-(trimethylammonium)propane. Upon addition of poly(ethylene glycol)-block-poly(propyl methacrylate-co-methacrylic acid) (PA), catHDL yields inhibition of internalization at neutral pH and its subsequent recovery at mildly acidic pH. catHDL forms a stable discoidal-shape complex with PA (catHDL/PA) (ca. 50nm in diameter), even in the presence of serum. Significant enhancement of endosomal escape of a catHDL component is observed after a 1-h treatment of human cancer cells with catHDL/PA. Doxorubicin and curcumin, fluorescent anti-cancer drugs, encapsulated into catHDL/PA are also translocated outside of endosomes, compared with that into catHDL, and their cytotoxicities are enhanced inside the cells. These data suggest that catHDL/PA may have a potential benefit to improve the cellular delivery and endosomal escape of therapeutics under mildly acidic conditions such as in tumor tissues. PMID:26959846

  6. Phase diagram of amorphous solid water: low-density, high-density, and very-high-density amorphous ices.

    PubMed

    Giovambattista, Nicolas; Stanley, H Eugene; Sciortino, Francesco

    2005-09-01

    We calculate the phase diagram of amorphous solid water by performing molecular dynamics simulations using the extended simple point charge (SPC/E) model. Our simulations follow different paths in the phase diagram: isothermal compression/decompression, isochoric cooling/heating, and isobaric cooling/heating. We are able to identify low-density amorphous (LDA), high-density amorphous (HDA), and very-high density amorphous (VHDA) ices. The density rho of these glasses at different pressure P and temperature T agree well with experimental values. We also study the radial distribution functions of glassy water. In agreement with experiments, we find that LDA, HDA, and VHDA are characterized by a tetrahedral hydrogen-bonded network and that, as compared to LDA, HDA has an extra interstitial molecule between the first and second shell. VHDA appears to have two such extra molecules. We obtain VHDA, as in experiment, by isobaric heating of HDA. We also find that "other forms" of glassy water can be obtained upon isobaric heating of LDA, as well as amorphous ices formed during the transformation of LDA to HDA. We argue that these other forms of amorphous ices, as well as VHDA, are not altogether new glasses but rather are the result of aging induced by heating. Samples of HDA and VHDA with different densities are recovered at normal P, showing that there is a continuum of glasses. Furthermore, the two ranges of densities of recovered HDA and recovered VHDA overlap at ambient P. Our simulations reproduce the experimental findings of HDA --> LDA and VHDA --> LDA transformations. We do not observe a VHDA --> HDA transformation, and our final phase diagram of glassy water together with equilibrium liquid data suggests that for the SPC/E model the VHDA --> HDA transformation cannot be observed with the present heating rates accessible in simulations. Finally, we discuss the consequences of our findings for the understanding of the transformation between the different amorphous

  7. Interchain electron states in polyethylene

    NASA Astrophysics Data System (ADS)

    Serra, S.; Tosatti, E.; Iarlori, S.; Scandolo, S.; Santoro, G.

    2000-08-01

    We present a theoretical study of the nature of the lowest empty conduction-band states in crystalline polyethylene (PE), conducted through density-functional electronic structure calculations. Results reveal that the wave function of the conduction-band edge is of interchain character, as opposed to the intrachain character of all the filled valence-band states. Thus, while a hole added to neutral PE will mainly belong to the PE chain backbone bonds, an added electron in PE will mostly reside between the chains, and far from the existing bonds. Moreover, the added electron state charge centroid is predicted to move further out from the chain backbone towards the low-density interstitial region, if and when the chains are pried apart. This suggests that injected electrons will naturally flow to low-density regions inside real PE, and that the experimentally established propensity of PE to expel electrons out of the bulk, should be directly related to the interchain nature of the conduction states.

  8. STEM-EELS analysis reveals stable high-density He in nanopores of amorphous silicon coatings deposited by magnetron sputtering.

    PubMed

    Schierholz, Roland; Lacroix, Bertrand; Godinho, Vanda; Caballero-Hernández, Jaime; Duchamp, Martial; Fernández, Asunción

    2015-02-20

    A broad interest has been showed recently on the study of nanostructuring of thin films and surfaces obtained by low-energy He plasma treatments and He incorporation via magnetron sputtering. In this paper spatially resolved electron energy-loss spectroscopy in a scanning transmission electron microscope is used to locate and characterize the He state in nanoporous amorphous silicon coatings deposited by magnetron sputtering. A dedicated MATLAB program was developed to quantify the helium density inside individual pores based on the energy position shift or peak intensity of the He K-edge. A good agreement was observed between the high density (∼35-60 at nm(-3)) and pressure (0.3-1.0 GPa) values obtained in nanoscale analysis and the values derived from macroscopic measurements (the composition obtained by proton backscattering spectroscopy coupled to the macroscopic porosity estimated from ellipsometry). This work provides new insights into these novel porous coatings, providing evidence of high-density He located inside the pores and validating the methodology applied here to characterize the formation of pores filled with the helium process gas during deposition. A similar stabilization of condensed He bubbles has been previously demonstrated by high-energy He ion implantation in metals and is newly demonstrated here using a widely employed methodology, magnetron sputtering, for achieving coatings with a high density of homogeneously distributed pores and He storage capacities as high as 21 at%. PMID:25627862

  9. Experimental study of high density foods for the Space Operations Center

    NASA Technical Reports Server (NTRS)

    Ahmed, S. M.

    1981-01-01

    The experimental study of high density foods for the Space Operations Center is described. A sensory evaluation of the high density foods was conducted first to test the acceptability of the products. A shelf-life study of the high density foods was also conducted for three different time lengths at three different temperatures. The nutritional analysis of the high density foods is at present incomplete.

  10. Launch Vehicle with Combustible Polyethylene Case Gasification Chamber Design Basis

    NASA Astrophysics Data System (ADS)

    Yemets, V.

    A single-stage launch vehicle equipped with a combustible tank shell of polyethylene and a moving propulsion plant is proposed. The propulsion plant is composed of a chamber for the gasification of the shell, a compressor of pyrolysed polyethylene and a magnetic powder obturator. It is shown that the “dental” structure of the gasification chamber is necessary to achieve the necessary contact area with the polyethylene shell. This conclusion is drawn from consideration of the thermo- physical properties of polyethylene, calculating quasisteady temperature field in the gasification chamber, estimating gasification rate of polyethylene, launch vehicle shortening rate and area of gasification. Experimental determination of the gasification rate is described. The gasification chamber specific mass as well as the propulsion plant weight-to-thrust ratio are estimated under some assumptions concerning the obturator and compressor. Combustible launch vehicles are compared with conventional launch vehicles taking into consideration their payload mass ratios. Combustible launchers are preferable as small launchers for micro and nano satellites. Reusable versions of such launchers seem suitable if polyethylene tank shells filled with metal or metal hydride fine dusts are used.

  11. High-density optical interconnects by using silicon photonics

    NASA Astrophysics Data System (ADS)

    Urino, Yutaka; Usuki, Tatsuya; Fujikata, Junichi; Ishizaka, Masashige; Yamada, Koji; Horikawa, Tsuyoshi; Nakamura, Takahiro; Arakawa, Yasuhiko

    2014-02-01

    One of the most serious challenges facing the exponential performance growth in the information industry is a bandwidth bottleneck in inter-chip interconnects. Optical interconnects with silicon photonics have been expected to solve the problem because of the intrinsic properties of optical signals and the industrial advantages of silicon for use in the electronics industry. We therefore propose an optical interconnect system by using silicon photonics to solve the problem. We examined integration between photonics and electronics and integration between light sources and silicon substrates, and we propose a photonics-electronics convergence system based on these examinations. We also investigated the configurations and characteristics of optical components for the system, including silicon spot-size converters, silicon optical waveguides, silicon optical splitters, silicon optical modulators, germanium photodetectors, and arrayed laser diodes. We then demonstrated the feasibility of the system by fabricating a high-density silicon optical interposer by using silicon photonics hybridly integrated with arrayed laser diodes and monolithically integrated with the other optical components on a single silicon substrate. The pad pitches of optical modulators and photodetectors were designed to be 100 μm so that LSI bare chips were able to contact to them electrically by flip-chip bonding. Since this system was optically complete and closed and no temperature sensitive component was used, we did not need to align the fibers, control the polarization, or control the temperature throughout the experiments. As a result, we achieved errorfree data links at 20 Gbps and high bandwidth density of 30 Tbps/cm2 with the silicon optical interposer.

  12. High-density fluids and the growth of monocrystalline diamonds

    NASA Astrophysics Data System (ADS)

    Weiss, Y.; Kiflawi, I.; Davies, N.; Navon, O.

    2014-09-01

    The chemical nature and composition of the growth medium of monocrystalline (MC) diamonds is still a matter of debate, partially because carbonate-bearing high-density fluids (HDFs) that are common in fibrous diamonds have not been found in MC diamonds. Here we report the first finding of HDF microinclusions in a MC octahedral diamond from Finsch, South Africa and in the MC octahedral core of a coated diamond from Kankan, Guinea; both diamonds carry nitrogen in B-centers. Numerous microinclusions in diamond Finsch_2a_cap1 are restricted to two thin layers parallel to the (1 1 1) face, ∼20 and 200 μm from the diamond rim. Low-Mg carbonatitic HDFs are found along the inner layer while the outer layer trapped saline compositions. The major and trace element compositions of the inclusions and their infrared spectra are highly similar to those of microinclusions found in fibrous diamonds. A few isolated microinclusions of saline compositions are scattered around a sulfide inclusion in the center of the octahedral core of diamond ON-KAN-383. This evidence for the involvement of oxidized fluids in the formation of MC diamonds adds to previous reports on the antiquity of HDFs in fibrous diamonds, the presence of carbonate and halide phases in inclusions in MC diamonds and the similarity of trace element pattern of a MC diamond to those of low-Mg carbonatitic HDF in fibrous diamonds. In addition, we show that the interaction of HDFs with depleted garnets can produce sinusoidal REE patterns which are one of the primary features of lherzolitic and harzburgitic garnet inclusions in MC diamonds. Together, these observations suggest that HDFs are involved in the formation of many types of diamonds from the Archaean to the Phanerozoic. HDFs are trapped in large quantities during rapid, fibrous growth, but must also be present during the growth of many MC diamonds.

  13. High density 3D printed microfluidic valves, pumps, and multiplexers.

    PubMed

    Gong, Hua; Woolley, Adam T; Nordin, Gregory P

    2016-07-01

    In this paper we demonstrate that 3D printing with a digital light processor stereolithographic (DLP-SLA) 3D printer can be used to create high density microfluidic devices with active components such as valves and pumps. Leveraging our previous work on optical formulation of inexpensive resins (RSC Adv., 2015, 5, 106621), we demonstrate valves with only 10% of the volume of our original 3D printed valves (Biomicrofluidics, 2015, 9, 016501), which were already the smallest that have been reported. Moreover, we show that incorporation of a thermal initiator in the resin formulation along with a post-print bake can dramatically improve the durability of 3D printed valves up to 1 million actuations. Using two valves and a valve-like displacement chamber (DC), we also create compact 3D printed pumps. With 5-phase actuation and a 15 ms phase interval, we obtain pump flow rates as high as 40 μL min(-1). We also characterize maximum pump back pressure (i.e., maximum pressure the pump can work against), maximum flow rate (flow rate when there is zero back pressure), and flow rate as a function of the height of the pump outlet. We further demonstrate combining 5 valves and one DC to create a 3-to-2 multiplexer with integrated pump. In addition to serial multiplexing, we also show that the device can operate as a mixer. Importantly, we illustrate the rapid fabrication and test cycles that 3D printing makes possible by implementing a new multiplexer design to improve mixing, and fabricate and test it within one day. PMID:27242064

  14. High-density lipoprotein, mitochondrial dysfunction and cell survival mechanisms.

    PubMed

    White, C Roger; Giordano, Samantha; Anantharamaiah, G M

    2016-09-01

    Ischemic injury is associated with acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting and open heart surgery. The timely re-establishment of blood flow is critical in order to minimize cardiac complications. Reperfusion after a prolonged ischemic period, however, can induce severe cardiomyocyte dysfunction with mitochondria serving as a major target of ischemia/reperfusion (I/R) injury. An increase in the formation of reactive oxygen species (ROS) induces damage to mitochondrial respiratory complexes leading to uncoupling of oxidative phosphorylation. Mitochondrial membrane perturbations also contribute to calcium overload, opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic mediators into the cytoplasm. Clinical and experimental studies show that ischemic preconditioning (ICPRE) and postconditioning (ICPOST) attenuate mitochondrial injury and improve cardiac function in the context of I/R injury. This is achieved by the activation of two principal cell survival cascades: 1) the Reperfusion Injury Salvage Kinase (RISK) pathway; and 2) the Survivor Activating Factor Enhancement (SAFE) pathway. Recent data suggest that high density lipoprotein (HDL) mimics the effects of conditioning protocols and attenuates myocardial I/R injury via activation of the RISK and SAFE signaling cascades. In this review, we discuss the roles of apolipoproteinA-I (apoA-I), the major protein constituent of HDL, and sphingosine 1-phosphate (S1P), a lysosphingolipid associated with small, dense HDL particles as mediators of cardiomyocyte survival. Both apoA-I and S1P exert an infarct-sparing effect by preventing ROS-dependent injury and inhibiting the opening of the mPTP. PMID:27150975

  15. Differential analysis for high density tiling microarray data

    PubMed Central

    Ghosh, Srinka; Hirsch, Heather A; Sekinger, Edward A; Kapranov, Philipp; Struhl, Kevin; Gingeras, Thomas R

    2007-01-01

    Background High density oligonucleotide tiling arrays are an effective and powerful platform for conducting unbiased genome-wide studies. The ab initio probe selection method employed in tiling arrays is unbiased, and thus ensures consistent sampling across coding and non-coding regions of the genome. These arrays are being increasingly used to study the associated processes of transcription, transcription factor binding, chromatin structure and their association. Studies of differential expression and/or regulation provide critical insight into the mechanics of transcription and regulation that occurs during the developmental program of a cell. The time-course experiment, which comprises an in-vivo system and the proposed analyses, is used to determine if annotated and un-annotated portions of genome manifest coordinated differential response to the induced developmental program. Results We have proposed a novel approach, based on a piece-wise function – to analyze genome-wide differential response. This enables segmentation of the response based on protein-coding and non-coding regions; for genes the methodology also partitions differential response with a 5' versus 3' versus intra-genic bias. Conclusion The algorithm built upon the framework of Significance Analysis of Microarrays, uses a generalized logic to define regions/patterns of coordinated differential change. By not adhering to the gene-centric paradigm, discordant differential expression patterns between exons and introns have been identified at a FDR of less than 12 percent. A co-localization of differential binding between RNA Polymerase II and tetra-acetylated histone has been quantified at a p-value < 0.003; it is most significant at the 5' end of genes, at a p-value < 10-13. The prototype R code has been made available as supplementary material [see Additional file 1]. PMID:17892592

  16. Statistical analysis of high density diffuse optical tomography

    PubMed Central

    Hassanpour, Mahlega S.; White, Brian R.; Eggebrecht, Adam T.; Ferradal, Silvina L.; Snyder, Abraham Z.; Culver, Joseph P.

    2014-01-01

    High density diffuse optical tomography (HD-DOT) is a noninvasive neuroimaging modality with moderate spatial resolution and localization accuracy. Due to portability and wear-ability advantages, HD-DOT has the potential to be used in populations that are not amenable to functional magnetic resonance imaging (fMRI), such as hospitalized patients and young children. However, whereas the use of event-related stimuli designs, general linear model (GLM) analysis, and imaging statistics are standardized and routine with fMRI, such tools are not yet common practice in HD-DOT. In this paper we adapt and optimize fundamental elements of fMRI analysis for application to HD-DOT. We show the use of event-related protocols and GLM de-convolution analysis in un-mixing multi-stimuli event-related HD-DOT data. Statistical parametric mapping (SPM) in the framework of a general linear model is developed considering the temporal and spatial characteristics of HD- DOT data. The statistical analysis utilizes a random field noise model that incorporates estimates of the local temporal and spatial correlations of the GLM residuals. The multiple-comparison problem is addressed using a cluster analysis based on non-stationary Gaussian random field theory. These analysis tools provide access to a wide range of experimental designs necessary for the study of the complex brain functions. In addition, they provide a foundation for understanding and interpreting HD-DOT results with quantitative estimates for the statistical significance of detected activation foci. PMID:23732886

  17. Distribution of High-Density Lipoprotein Subfractions and Hypertensive Status

    PubMed Central

    Zhang, Yan; Li, Sha; Xu, Rui-Xia; Guo, Yuan-Lin; Wu, Na-Qiong; Zhu, Cheng-Gang; Gao, Ying; Dong, Qian; Liu, Geng; Sun, Jing; Li, Jian-Jun

    2015-01-01

    Abstract The exact mechanisms of hypertension contributing to atherosclerosis have not been fully elucidated. Although multiple studies have clarified the association with low-density lipoprotein (LDL) subfractions, uncertainty remains about its relationship with high-density lipoprotein (HDL) subfractions. Therefore, we aimed to comprehensively determine the relationship between distribution of HDL subfractions and hypertensive status. A total of 953 consecutive subjects without previous lipid-lowering drug treatment were enrolled and were categorized based on hypertension history (with hypertension [n = 550] or without hypertension [n = 403]). Baseline clinical and laboratory data were collected. HDL separation was performed using the Lipoprint System. Plasma large HDL-cholesterol (HDL-C) and large HDL percentage were dramatically lower whereas the small HDL-C and small HDL percentage were higher in patients with hypertension (all P < 0.05). The antihypertensive drug therapy was not associated with large or small HDL subfractions (on treatment vs not on treatment, P > 0.05; combination vs single drug therapy, P > 0.05). However, the blood pressure well-controlled patients have significantly lower small HDL subfraction (P < 0.05). Moreover, large HDL-C and percentage were inversely whereas small HDL percentage was positively associated with incident hypertension after adjusting potential confounders (all P < 0.05). In the multivariate model conducted in patients with and without hypertension separately, the cardio-protective value of large HDL-C was disappeared in patients with hypertension (OR 95%CI: 1.011 [0.974–1.049]). The distribution of HDL subfractions is closely associated with hypertensive status and hypertension may potentially impact the cardio-protective value of large HDL subfraction. PMID:26512616

  18. Proprotein convertases in high-density lipoprotein metabolism.

    PubMed

    Choi, Seungbum; Korstanje, Ron

    2013-01-01

    The proprotein convertase subtilisin/kexins (PCSKs) are a serine endopeptidase family. PCSK members cleave amino acid residues and modulate the activity of precursor proteins. Evidence from patients and animal models carrying genetic alterations in PCSK members show that PCSK members are involved in various metabolic processes. These studies further revealed the molecular mechanism by which genetic alteration of some PCSK members impairs normal molecular and physiological functions, which in turn lead to cardiovascular disease. High-density lipoprotein (HDL) is anti-atherogenic as it removes excessive amount of cholesterol from blood and peripheral tissues. Several PCSK members are involved in HDL metabolism. PCSK3, PCSK5, and PCSK6 process two triglyceride lipase family members, endothelial lipase and lipoprotein lipase, which are important for HDL remodeling. Recent studies in our lab found evidence that PCSK1 and PCSK9 are also involved in HDL metabolism. A mouse model carrying an amino acid substitution in PCSK1 showed an increase in serum apolipoprotein A1 (APOA1) level. Another mouse model lacking PCSK9 showed a decrease in APOE-containing HDL. In this review, we summarize the role of the five PCSK members in lipid, glucose, and bile acid (BA) metabolism, each of which can influence HDL metabolism. We propose an integrative model in which PCSK members regulate HDL metabolism through various molecular mechanisms and metabolic processes and genetic variation in some PCSK members may affect the efficiency of reverse cholesterol transport. PCSK members are considered as attractive therapeutic targets. A greater understanding of the molecular and physiological functions of PCSK members will improve therapeutic strategies and drug efficacy for cardiovascular disease where PCSK members play critical role, with fewer adverse effects. PMID:24252756

  19. Surface interactions involved in flashover with high density electronegative gases.

    SciTech Connect

    Hodge, Keith Conquest; Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Wallace, Zachariah Red; Lehr, Jane Marie

    2010-01-01

    This report examines the interactions involved with flashover along a surface in high density electronegative gases. The focus is on fast ionization processes rather than the later time ionic drift or thermalization of the discharge. A kinetic simulation of the gas and surface is used to examine electron multiplication and includes gas collision, excitation and ionization, and attachment processes, gas photoionization and surface photoemission processes, as well as surface attachment. These rates are then used in a 1.5D fluid ionization wave (streamer) model to study streamer propagation with and without the surface in air and in SF6. The 1.5D model therefore includes rates for all these processes. To get a better estimate for the behavior of the radius we have studied radial expansion of the streamer in air and in SF6. The focus of the modeling is on voltage and field level changes (with and without a surface) rather than secondary effects, such as, velocities or changes in discharge path. An experiment has been set up to carry out measurements of threshold voltages, streamer velocities, and other discharge characteristics. This setup includes both electrical and photographic diagnostics (streak and framing cameras). We have observed little change in critical field levels (where avalanche multiplication sets in) in the gas alone versus with the surface. Comparisons between model calculations and experimental measurements are in agreement with this. We have examined streamer sustaining fields (field which maintains ionization wave propagation) in the gas and on the surface. Agreement of the gas levels with available literature is good and agreement between experiment and calculation is good also. Model calculations do not indicate much difference between the gas alone versus the surface levels. Experiments have identified differences in velocity between streamers on the surface and in the gas alone (the surface values being larger).

  20. High density transcriptional mapping of chromosome 21 by hybridization selection

    SciTech Connect

    Tassone, F.; Wade, H.; Gardiner, K.

    1994-09-01

    A transcriptional map of human chromosome 21 is important for the study of Down syndrome, development processes and genome organization. To construct a high density transcriptional map, the technique of cDNA hybrid selection is being applied to a minimal tiling path of YAC clones that span 21q. The cDNA used for selection represents a complex pool of sequences obtained from a variety of fetal and adult tissues and cell lines. Approximately 70-80 YAC clones are sufficient to span 21q; each is individually processed through the selection procedure to obtain a YAC-specific {open_quotes}selected cDNA library{close_quotes}. Survey analysis of each library includes determination of levels of ribosomal contamination, verification of enrichment of control genes, identification of a preliminary number of novel unique sequences, and verification that novel sequences map to the correct YAC and chromosomal regions. This analysis has been completed for 19 YACs that together comprise approximately 10 Mb of non-overlapping DNA, 25% of the long arm. Ribosomal cDNA contamination is low (<10%) and all known genes of appropriate tissue specificity of expression have been recovered, as well as new genes from each YAC. Libraries of expression have been recovered, as well as new genes from each YAC. Libraries from 8 of these YACs are now being subjected to exhaustive analysis to identify all novel genes contained within them and to obtain complete cDNAs and expression analysis for each. Not all regions of the chromosome, however, are equally amenable to these analyses. Selected cDNA libraries from the centromeric YACs are yielding apparently novel genes, but confirmation of map position is problematic. Also of interest is a region of several megabases within the Giemsa dark band, 21q21. Selected cDNA libraries from these YACs so far have yielded no novel genes and support the idea of a genuinely very gene-poor region.

  1. High-density lipoprotein subpopulations in pathologic conditions.

    PubMed

    Asztalos, Bela F; Schaefer, Ernst J

    2003-04-01

    The role of low-density lipoprotein (LDL) cholesterol in coronary artery disease (CAD) and the impact of therapeutic agents on LDL cholesterol are well established. Less is known about the role of high-density lipoprotein (HDL) cholesterol and even less about the role of the different HDL subspecies in CAD. HDL particles vary in size and density, mainly because of differences in the number of apolipoprotein (apo) particles and the amount of cholesterol ester in the core of HDL. Apo A-I is essential and, together with lipid, sufficient for the formation of HDL particles. Apo A-I-containing HDL particles play a primary role in cholesterol efflux from membranes, at least in part through interactions with the adenosine triphosphate-binding cassette transporter A1 (ABCA1). Patients with Tangier disease have mutations in the gene encoding ABCA1, which result in functionally impaired protein, a marked deficiency in HDL cholesterol, and a high risk of premature CAD. Our studies of apo A-I-containing HDL subpopulations in various patient populations reveal that patients homozygous for Tangier disease have only the pre-beta(1) HDL subspecies. Tangier heterozygotes are severely depleted in the larger alpha- and pre-alpha-mobility subspecies. Patients with low HDL cholesterol levels and those with CAD also show deficiencies in the alpha(1) and pre-alpha(1-3) HDL subspecies. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) increase the levels of the large alpha(1) and pre-alpha(1) subpopulations and decrease the level of the small alpha(3) subpopulation. Thus, atorvastatin, for example, significantly moves the distribution of HDL particles toward normal, followed by simvastatin, pravastatin, and lovastatin in decreasing order of efficiency. A new statin, rosuvastatin, produces greater increases in HDL cholesterol than atorvastatin, but its effect on HDL particle distribution is yet to be determined. PMID:12679198

  2. Speciated Human High Density Lipoprotein Protein Proximity Profiles†

    PubMed Central

    Gauthamadasa, Kekulawalage; Rosales, Corina; Pownall, Henry J.; Macha, Stephen; Jerome, W. Gray; Huang, Rong; Silva, R. A.Gangani. D.

    2010-01-01

    It is expected that the attendant structural heterogeneity of human high density lipoprotein (HDL) complexes is a determinant of its varied metabolic functions. To determine structural heterogeneity of HDL, major apolipoprotein stoichiometry profiles in human HDL were determined. First, HDL was separated into two main populations, with and without apolipoprotein (apo) A-II, LpA-I and LpA-I/A-II respectively. Each main population was further separated into six individual subfractions using size exclusion chromatography (SEC). Protein proximity profiles (PPP) of major apolipoproteins in each individual subfraction was determined by optimally cross-linking apolipoproteins within individual particles with bis(sulfosuccinimidyl)suberate (BS3), a bifunctional cross linker, followed by molecular weight determination by MALDI-MS. The PPPs of LpA-I subfractions indicated that the number of apoA-I molecules increased from two to three to four upon increase in the LpA-I particle size. On the other hand, the entire population of LpA-I/A-II demonstrated the presence of only two proximal apoA-I molecules per particle, while the number of apoA-II molecules varied from one dimeric apoA-II to two and then to three. For most of the above PPP profiles, an additional population that contained a single molecule of apoC-III in addition to apoA-I and/or apoA-II was detected. Upon composition analyses of individual subpopulations, LpA-I/A-II displayed comparable proportions for total protein (~58%), phospholipids (~21%) total cholesterol (~16%), triglycerides (~5%) and free cholesterol (~4%) across subfractions. LpA-I components, on the other hand, showed significant variability. This novel information on HDL subfractions will form a basis for better understanding particle specific functions of HDL. PMID:21073165

  3. Biomimetic High-Density Lipoproteins from a Gold Nanoparticle Template

    NASA Astrophysics Data System (ADS)

    Luthi, Andrea Jane

    For hundreds of years the field of chemistry has looked to nature for inspiration and insight to develop novel solutions for the treatment of human diseases. The ability of chemists to identify, mimic, and modifiy small molecules found in nature has led to the discovery and development of many important therapeutics. Chemistry on the nanoscale has made it possible to mimic natural, macromolecular structures that may also be useful for understanding and treating diseases. One example of such a structure is high-density lipoprotein (HDL). The goal of this work is to use a gold nanoparticle (Au NP) as a template to synthesize functional mimics of HDL and characterize their structure and function. Chapter 1 details the structure and function of natural HDL and how chemistry on the nanoscale provides new strategies for mimicking HDL. This Chapter also describes the first examples of using nanoparticles to mimic HDL. Chapter 2 reports the synthesis and characterization of biomimetic HDL using different sizes of Au NPs and different surface chemistries and how these variables can be used to tailor the properties of biomimetic HDL. From these studies the optimal strategy for synthesizing biomimetic HDL was determined. In Chapter 3, the optimization of the synthesis of biomimetic HDL is discussed as well as a full characterization of its structure. In addition, the work in this chapter shows that biomimetic HDL can be synthesized on a large scale without alterations to its structure or function. Chapter 4 focuses on understanding the pathways by which biomimetic HDL accepts cholesterol from macrophage cells. The results of these studies demonstrate that biomimetic HDL is able to accept cholesterol by both active and passive pathways of cholesterol efflux. In Chapter 5 the preliminary results of in vivo studies to characterize the pharmacokinetics and pharmacodynamics of biomimetic HDL are presented. These studies suggest that biomimetic HDL traffics through tissues prone to

  4. Quantitative and qualitative analysis of polyethylene wear particles in synovial fluid of patients with total knee arthroplasty. A preliminary report.

    PubMed

    Bosco, J; Benjamin, J; Wallace, D

    1994-12-01

    Synovial fluid from 13 knees undergoing revision total knee arthroplasty was subjected to chemical digestion and ultrafiltration. Scanning electron microscopy was used to visualize high-density polyethylene particles filtered from the fluid, and the images were analyzed using digital imaging software. This data were correlated with polyethylene wear patterns seen at the time of revision surgery. Patients' prostheses with gross polyethylene wear were differentiated from those with surface deformation and burnishing. The knees had been in situ for periods ranging from 3 to 112 months, and included 6 different prosthetic designs. The average area of the polyethylene particles measured ranged from 41 to 701 mu 2, and the total number of particles identified for each sample ranged from 38 to 279 mu 2. The largest particle identified had a surface area of 17,500 mu 2. Using the fluid volume analyzed, the particle area per milliliter of synovial fluid examined was calculated, and values ranged from 6.22 x 10(4) to 2.06 x 10(6) mu 2/ml. Visualization of high-density polyethylene using scanning electron microscopy allows greater resolution of morphologic detail than is possible with routine histologic examination using light microscopy. There were trends toward increasing particle size and total particle area in patients with gross polyethylene wear. The area of high-density polyethylene per milliliter of fluid in patients with gross wear was found to be statistically greater than that of patients without gross wear (p = 0.047). This technique offers a potentially valuable method of evaluating the status of high-density-polyethylene bearing surfaces in situ using a noninvasive technique. PMID:7994947

  5. Method of fabricating high-density hermetic electrical feedthroughs

    SciTech Connect

    Shah, Kedar G.; Pannu, Satinderpall S.; Delima, Terri L.

    2015-06-02

    A method of fabricating electrical feedthroughs selectively removes substrate material from a first side of an electrically conductive substrate (e.g. a bio-compatible metal) to form an array of electrically conductive posts in a substrate cavity. An electrically insulating material (e.g. a bio-compatible sealing glass) is then flowed to fill the substrate cavity and surround each post, and solidified. The solidified insulating material is then exposed from an opposite second side of the substrate so that each post is electrically isolated from each other as well as the bulk substrate. In this manner a hermetic electrically conductive feedthrough construction is formed having an array of electrical feedthroughs extending between the first and second sides of the substrate from which it was formed.

  6. STARCH FILLED TERNARY POLYMER COMPOSITES I: DYNAMIC MECHANICAL PROPERTIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been shown that the dynamic mechanical properties of starch filled blends of polyethylene (PE) and poly (hydroxy ester ether) (PHEE) are strongly dependent on the properties and distribution of the minor component of the blend (PHEE). The effect of this minor component on the viscoelastic pr...

  7. High-Density, High-Bandwidth, Multilevel Holographic Memory

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin

    2008-01-01

    A proposed holographic memory system would be capable of storing data at unprecedentedly high density, and its data transfer performance in both reading and writing would be characterized by exceptionally high bandwidth. The capabilities of the proposed system would greatly exceed even those of a state-of-the art memory system, based on binary holograms (in which each pixel value represents 0 or 1), that can hold .1 terabyte of data and can support a reading or writing rate as high as 1 Gb/s. The storage capacity of the state-of-theart system cannot be increased without also increasing the volume and mass of the system. However, in principle, the storage capacity could be increased greatly, without significantly increasing the volume and mass, if multilevel holograms were used instead of binary holograms. For example, a 3-bit (8-level) hologram could store 8 terabytes, or an 8-bit (256-level) hologram could store 256 terabytes, in a system having little or no more size and mass than does the state-of-the-art 1-terabyte binary holographic memory. The proposed system would utilize multilevel holograms. The system would include lasers, imaging lenses and other beam-forming optics, a block photorefractive crystal wherein the holograms would be formed, and two multilevel spatial light modulators in the form of commercially available deformable-mirror-device spatial light modulators (DMDSLMs) made for use in high speed input conversion of data up to 12 bits. For readout, the system would also include two arrays of complementary metal oxide/semiconductor (CMOS) photodetectors matching the spatial light modulators. The system would further include a reference-beam sterring device (equivalent of a scanning mirror), containing no sliding parts, that could be either a liquid-crystal phased-array device or a microscopic mirror actuated by a high-speed microelectromechanical system. Time-multiplexing and the multilevel nature of the DMDSLM would be exploited to enable writing

  8. High-Density Plasma Reactors: Simulations for Design

    NASA Technical Reports Server (NTRS)

    Hash, David B.; Meyyappan, Meyya; Arnold, James O. (Technical Monitor)

    1998-01-01

    The development of improved and more efficient plasma reactors is a costly process for the semiconductor industry. Until five years ago, the Industry made most of its advancements through a trial and error approach. More recently, the role of computational modeling in the design process has increased. Both conventional computational fluid dynamics (CFD) techniques like Navier-Stokes solvers as well as particle simulation methods are used to model plasma reactor flowfields. However, since high-density plasma reactors generally operate at low gas pressures on the order of 1 to 10 mTorr, a particle simulation may be necessary because of the failure of CFD techniques to model rarefaction effects. The direct simulation Monte Carlo method is the most widely accepted and employed particle simulation tool and has previously been used to investigate plasma reactor flowfields. A plasma DSMC code is currently under development at NASA Ames Research Center with its foundation as the object-oriented parallel Cornell DSMC code, MONACO. The present investigation is a follow up of a neutral flow investigation of the effects of process parameters as well as reactor design on etch rate and etch rate uniformity. The previous work concentrated on silicon etch of a chlorine flow in a configuration typical of electron cyclotron resonance (ECR) or helical resonator type reactors. The effects of the plasma on the dissociation chemistry were modeled by making assumptions about the electron temperature and number density. The electrons or ions themselves were not simulated.The present work extends these results by simulating the charged species.The electromagnetic fields are calculated such that power deposition is modeled self-consistently. Electron impact reactions are modeled along with mechanisms for charge exchange. An bipolar diffusion assumption is made whereby electrons remain tied to the ions. However, the velocities of tile electrons are allowed to be modified during collisions

  9. Fracture in stress engineered, high density, thin film interconnects

    NASA Astrophysics Data System (ADS)

    Modi, Mitul Bharat

    The micro-contact spring is a new technology that is based on physically vapor deposited thin film cantilevers with a purposely-imposed stress gradient through the thickness of the film. These "springs" have the potential to meet the long and near term high-density packaging and probing challenges, as outlined by the International Technology Roadmap for Semiconductors. The success of this technology is, in part, dependent on the ability to create springs that are reliable against interfacial fracture during fabrication, microelectronic probing, and microelectronic packaging applications. Through this research, a framework to understand the interfacial integrity of thin film cantilevers under monotonic and cyclic loading has been established. This research has developed a modified decohesion test (MDT) that eliminates the shortcomings of current interfacial fracture toughness measurement methods for thin film interfaces. This highly flexible and robust test gives tight bounds on the fracture toughness using a single sample, generates any mode mix, creates an interface representative of microelectronic or MEMS applications, and remains in the linear elastic fracture mechanics regime. The MDT was applied to investigate the interfacial fracture toughness of two material systems relevant to micro-contact spring applications: titanium/silicon and titanium/Al 2O3. A von Karman Plate Theory (VKPT) based analytical method was applied and further enhanced in this research to analytically model the large, nonlinear behavior of intrinsically stressed, thin film, cantilever strips. The multilayer analytical approach, based on simply supported plates, was shown to predict the energy release rate of cantilevered strips during monotonic fracture remarkably well and showed the importance of bifurcation of curvature in understanding the nonlinear behavior of intrinsically stressed thin film cantilever plates. A framework for numerical modeling of micro-contact springs in fabrication

  10. Fuel-rich catalytic combustion of a high density fuel

    NASA Technical Reports Server (NTRS)

    Brabbs, Theodore A.; Merritt, Sylvia A.

    1993-01-01

    Fuel-rich catalytic combustion (ER is greater than 4) of the high density fuel exo-tetrahydrocyclopentadiene (JP-10) was studied over the equivalence ratio range 5.0 to 7.6, which yielded combustion temperatures of 1220 to 1120 K. The process produced soot-free gaseous products similar to those obtained with iso-octane and jet-A in previous studies. The measured combustion temperature agreed well with that calculated assuming soot was not a combustion product. The process raised the effective hydrogen/carbon (H/C) ratio from 1.6 to over 2.0, thus significantly improving the combustion properties of the fuel. At an equivalence ratio near 5.0, about 80 percent of the initial fuel carbon was in light gaseous products and about 20 percent in larger condensable molecules. Fuel-rich catalytic combustion has now been studied for three fuels with H/C ratios of 2.25 (iso-octane), 1.92 (jet-A), and 1.6 (JP-10). A comparison of the product distribution of these fuels shows that, in general, the measured concentrations of the combustion products were monotonic functions of the H/C ratio with the exception of hydrogen and ethylene. In these cases, data for JP-10 fell between iso-octane and jet-A rather than beyond jet-A. It is suggested that the ring cross-linking structure of JP-10 may be responsible for this behavior. All the fuels studied showed that the largest amounts of small hydrocarbon molecules and the smallest amounts of large condensable molecules occurred at the lower equivalence ratios. This corresponds to the highest combustion temperatures used in these studies. Although higher temperatures may improve this mix, the temperature is limited. First, the life of the present catalyst would be greatly shortened when operated at temperatures of 1300 K or greater. Second, fuel-rich catalytic combustion does not produce soot because the combustion temperatures used in the experiments were well below the threshold temperature (1350 K) for the formation of soot. Increasing

  11. Kaon condensation in baryonic Fermi liquid at high density

    NASA Astrophysics Data System (ADS)

    Paeng, Won-Gi; Rho, Mannque

    2015-01-01

    We formulate kaon condensation in dense baryonic matter with antikaons fluctuating from the Fermi-liquid fixed point. This entails that in the Wilsonian renormalization group (RG) approach, the decimation is effectuated in the baryonic sector to the Fermi surface while in the meson sector to the origin. In writing the kaon-baryon (KN) coupling, we take a generalized hidden local symmetry Lagrangian for the meson sector endowed with a "mended symmetry" that has the unbroken symmetry limit at high density in which the Goldstone π , scalar s , and vectors ρ (and ω ) and a1 become massless. The vector mesons ρ (and ω ) and a1 can be identified as emergent (hidden) local gauge fields and the scalar s as the dilaton field of the spontaneously broken scale invariance at chiral restoration. In matter-free space, when the vector mesons and the scalar meson—whose masses are much greater than that of the pion—are integrated out, then the resulting KN coupling Lagrangian consists of the leading chiral order [O (p1) ] Weinberg-Tomozawa term and the next chiral order [O (p2) ] ΣKN term. In addressing kaon condensation in dense nuclear matter in chiral perturbation theory, one makes an expansion in the "small" Fermi momentum kF. We argue that in the Wilsonian RG formalism with the Fermi-liquid fixed point, the expansion is on the contrary in 1 /kF with the "large" Fermi momentum kF. The kaon-quasinucleon interaction resulting from integrating out the massive mesons consists of a "relevant" term from the scalar exchange (analog to the ΣKN term) and an "irrelevant" term from the vector-meson exchange (analog to the Weinberg-Tomozawa term). It is found that the critical density predicted by the latter approach, controlled by the relevant term with the irrelevant term suppressed, is three times less than that predicted by chiral perturbation theory. This would make kaon condensation take place at a much lower density than previously estimated in chiral perturbation theory.

  12. High-density lipoprotein proteome dynamics in human endotoxemia

    PubMed Central

    2011-01-01

    Background A large variety of proteins involved in inflammation, coagulation, lipid-oxidation and lipid metabolism have been associated with high-density lipoprotein (HDL) and it is anticipated that changes in the HDL proteome have implications for the multiple functions of HDL. Here, SELDI-TOF mass spectrometry (MS) was used to study the dynamic changes of HDL protein composition in a human experimental low-dose endotoxemia model. Ten healthy men with low HDL cholesterol (0.7+/-0.1 mmol/L) and 10 men with high HDL cholesterol levels (1.9+/-0.4 mmol/L) were challenged with endotoxin (LPS) intravenously (1 ng/kg bodyweight). We previously showed that subjects with low HDL cholesterol are more susceptible to an inflammatory challenge. The current study tested the hypothesis that this discrepancy may be related to differences in the HDL proteome. Results Plasma drawn at 7 time-points over a 24 hour time period after LPS challenge was used for direct capture of HDL using antibodies against apolipoprotein A-I followed by subsequent SELDI-TOF MS profiling. Upon LPS administration, profound changes in 21 markers (adjusted p-value < 0.05) were observed in the proteome in both study groups. These changes were observed 1 hour after LPS infusion and sustained up to 24 hours, but unexpectedly were not different between the 2 study groups. Hierarchical clustering of the protein spectra at all time points of all individuals revealed 3 distinct clusters, which were largely independent of baseline HDL cholesterol levels but correlated with paraoxonase 1 activity. The acute phase protein serum amyloid A-1/2 (SAA-1/2) was clearly upregulated after LPS infusion in both groups and comprised both native and N-terminal truncated variants that were identified by two-dimensional gel electrophoresis and mass spectrometry. Individuals of one of the clusters were distinguished by a lower SAA-1/2 response after LPS challenge and a delayed time-response of the truncated variants. Conclusions

  13. Executive Dysfunction and Reward Dysregulation: A High-Density Electrical Mapping Study in Cocaine Abusers

    PubMed Central

    Morie, Kristen P.; De Sanctis, Pierfilippo; Garavan, Hugh; Foxe, John J.

    2015-01-01

    Executive function deficits and reward dysregulation, which mainly manifests as anhedonia, are well documented in drug abusers. We investigated specific aspects of executive function (inhibitory control and cognitive control), as well as anhedonia, in a cohort of current cocaine abusers in order to ascertain to what extent these factors are associated with more severe drug dependence. Participants filled out questionnaires relating to anhedonia and their addiction history. Participants also performed a response inhibition task while high-density event-related potentials (ERPs) were recorded. Electrophysiological responses to successful inhibitions (N2/P3 components) and to commission errors (ERN/Pe components) were compared between 23 current users of cocaine and 27 non-using controls. A regression model was performed to determine the association of our measures of reward dysregulation and executive function with addiction severity. As expected, cocaine users performed more poorly than controls on the inhibitory control task and showed significant electrophysiological differences. They were also generally more anhedonic than controls. Higher levels of anhedonia were associated with more severe substance use, whereas the level of executive dysfunction was not associated with more severe substance use. However, N2 amplitude was associated with duration of drug use. Further, inhibitory control and anhedonia were correlated, but only in controls. These data suggest that while executive dysfunction characterizes drug abuse, it is anhedonia, independent of executive dysfunction, that is most strongly associated with more severe use. PMID:24911989

  14. Dielectric properties of high-density-plasma fluorinated-silicate glass by doping nitrogen

    SciTech Connect

    Wei, B. J.; Cheng, Y. L.; Wang, Y. L.; Lu, F. H.; Shih, H. C.

    2008-05-15

    Nitrogen-doped fluorinated-silicate-glass (N-FSG) films were prepared by adding N{sub 2} gas to the SiH{sub 4}/SiF{sub 4}/O{sub 2}/Ar gas mixtures using high-density-plasma (HDP) chemical vapor deposition method. When N{sub 2} is increasingly added, the fluorine concentration of the films increases and the dielectric constant decreases from 3.8 to 3.4. In addition, better gap-filling ability is obtained by adding N{sub 2} due to a lowered deposition/(sputtering+etching) (D/S+E) ratio. Moreover, these films were stabilized by a decreased change in dielectric constant after thermal treatment; indicating a significant improvement in the thermal resistivity of the films. It is proposed that the improvement of stability is correlated with the reduction of unstable fluorine bonds in the N-FSG films. Furthermore, the thermal stability of the N-FSG films was also identified by Al wiring delamination check. After annealing, the blister was observed only in non-N{sub 2} FSG film with 5.5% Si-F concentration, while no blisters or delamination were observed when N{sub 2} is introduced into the FSG process. Therefore, the N-FSG film, deposited by HDP-chemical vapor deposition, was a good candidate for the interconnect dielectric application.

  15. Attenuation of heavy metals by geosynthetics in the coal gangue-filled columns.

    PubMed

    Wang, Ping; Hu, Zhenqi; Wang, Peijun

    2013-01-01

    In the subsided areas backfilled with coal gangue, an issue of continuing environmental concern is the migration of hazardous metals to the subsurface soil and groundwater. As an effective isolation material, geosynthetics have been scarcely applied into mining areas reclamation of China. This paper describes research aimed at characterizing the behaviours of different geosynthetics in the leaching columns filled with coal gangues. Four types of geosynthetics were selected: fibres needle-punched nonwoven geotextiles, high-density polyethylene, needle-punched Na-bentonite geosynthetic clay liner (GCL-NP) and Na-bentonite geosynthetic-overbited film. Heavy metals were significantly attenuated and by monitoring aqueous solutions in the whole percolation period, negative correlation was found between pH value and concentration of heavy metals. Generally, GCL-NP showed comparatively better effects on attenuating the migration of heavy metals. According to the meta-analysis of heavy metals present in the leachates and retained in the columns, geosynthetics have good capabilities of sorption and retardation, which can delay the breakthrough time of heavy metals and retard the accumulation in the subsurface. Future research will use X-ray diffraction and micro-imaging (electron microprobe and scanning electron microscopy) to further explain retention mechanisms. PMID:24527654

  16. Effect of gamma irradiation on mechanical, thermal and rheological behavior of HDPE filled with seaweed residues

    NASA Astrophysics Data System (ADS)

    Cataño, L.; Albano, C.; Karam, A.; Domínguez, N.; Sánchez, Y.; González, J.

    2005-07-01

    The present work shows the results obtained during the investigation of the influence of gamma irradiation on mechanical, thermal and rheological properties of high-density polyethylene (HDPE) filled with seaweed residues (SR). The SR used was located on Venezuelan coastlines and they are composed mainly by CaCO3 in aragonite phase. The HDPE was extruded along with the filler at different compositions (20, 30 and 40 wt.%). The composites were exposed to a 60Co source irradiated at 25 and 100 kGy. From the obtained results, it was noticed that Young modulus remained constant with filler content. Moreover, the influence of filler content was found to be more prominent on properties like tensile stress and elongation at break. On the other hand, thermal analysis showed that filler content had no significant influence on thermal stability. Still, it is necessary to point out that low radiation doses improved thermal stability of the composites. From rheological studies it was observed a decreasing of melt flow index (MFI) by increasing the SR amount and radiation. Therefore, was determinate that high filler content composites are the best choice to be considered for biomedical and industrial applications.

  17. Developing High-Density Diffuse Optical Tomography for Neuroimaging

    NASA Astrophysics Data System (ADS)

    White, Brian Richard

    Clinicians who care for brain-injured patients and premature infants desire a bedside monitor of brain function. A decade ago, there was hope that optical imaging would be able to fill this role, as it combined fMRI's ability to construct cortical maps with EEG's portable, cap-based systems. However, early optical systems had poor imaging performance, and the momentum for the technique slowed. In our lab, we develop diffuse optical tomography (DOT), which is a more advanced method of performing optical imaging. My research has been to pioneer the in vivo use of DOT for advanced neuroimaging by (1) quantifying the advantages of DOT through both in silico simulation and in vivo performance metrics, (2) restoring confidence in the technique with the first retinotopic mapping of the visual cortex (a benchmark for fMRI and PET), and (3) creating concepts and methods for the clinical translation of DOT. Hospitalized patients are unable to perform complicated neurological tasks, which has motivated us to develop the first DOT methods for resting-state brain mapping with functional connectivity. Finally, in collaboration with neonatologists, I have extended these methods with proof-of-principle imaging of brain-injured premature infants. This work establishes DOT's improvements in imaging performance and readies it for multiple clinical and research roles.

  18. Use of prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent

    NASA Astrophysics Data System (ADS)

    Priyada, P.; Sarkar, P. K.

    2015-06-01

    The possibility of using measured prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent is explored theoretically. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of a high density polyethylene cylinder to emit prompt gammas from interaction of neutrons with the nuclei of hydrogen and carbon present in polyethylene. The neutron energy dependent responses of hydrogen and carbon nuclei are combined appropriately to match the energy dependent neutron fluence to ambient dose equivalent conversion coefficients. The proposed method is tested initially with simulated spectra and then validated using experimental measurements with an Am-Be neutron source. Experimental measurements and theoretical simulations have established the feasibility of estimating neutron ambient dose equivalent using measured neutron induced prompt gammas emitted from polyethylene with an overestimation of neutron dose at very low energies.

  19. Initial Stages of the Pyrolysis of Polyethylene.

    PubMed

    Popov, Konstantin V; Knyazev, Vadim D

    2015-12-10

    An experimental study of the kinetics of the initial stages of the pyrolysis of high-density polyethylene (PE) was performed. Quantitative yields of gas-phase products (C1-C8 alkanes and alkenes) and functional groups within the remaining polyethylene melt (methyl, vinyl, vinylene, vinylidene, and branching sites) were obtained as a function of time (0-20 min) at five temperatures in the 400-440 °C range. Gas chromatography and NMR ((1)H and (13)C) were used to detect the gas- and condensed-phase products, respectively. Modeling of polyethylene pyrolysis was performed, with the primary purpose of determining the rate constants of several critical reaction types important at the initial pyrolysis stages. Detailed chemical mechanisms were created (short and extended mechanisms) and used with both the steady-state approximation and numerical integration of the differential kinetic equations. Rate constants of critical elementary reactions (C-C backbone scission, two kinds of H-atom transfer, radical addition to the double bond, and beta-scission of tertiary alkyl radicals) were adjusted, resulting in an agreement between the model and the experiment. The values of adjusted rate constants are in general agreement with those of cognate reactions of small molecules in the gas phase, with the exception of the rate constants of the backbone C-C scission, which is found to be approximately 1-2 orders of magnitude lower. This observation provides tentative support to the hypothesis that congested PE melt molecular environment impedes the tumbling motions of separating fragments in C-C bond scission, thus resulting in less "loose" transition state and lower rate constant values. Sensitivity of the calculations to selected uncertainties in model properties was studied. Values and estimated uncertainties of four combinations of rate constants are reported as derived from the experimental results via modeling. The dependence of the diffusion-limited rate constant for radical

  20. Polyethylene Glycol Propionaldehydes

    NASA Technical Reports Server (NTRS)

    Harris, Joe M.; Sedaghat-Herati, Mohammad R.; Karr, Laurel J.

    1992-01-01

    New class of compounds derived from polyethylene glycol (PEG's) namely, PEG-propionaldehydes, offers two important advantages over other classes of PEG aldehyde derivatives: compounds exhibit selective chemical reactivity toward amino groups and are stable in aqueous environment. PEG's and derivatives used to couple variety of other molecules, such as, to tether protein molecules to surfaces. Biotechnical and biomedical applications include partitioning of two phases in aqueous media; immobilization of such proteins as enzymes, antibodies, and antigens; modification of drugs; and preparation of protein-rejecting surfaces. In addition, surfaces coated with PEG's and derivatives used to control wetting and electroosmosis. Another potential application, coupling to aminated surfaces.

  1. Disintegration of porous polyethylene prostheses.

    PubMed

    Kerr, A G; Riley, D N

    1999-06-01

    A Plastipore (porous polyethylene) Total Ossicular Replacement Prosthesis gave an excellent initial hearing result which was maintained for 14 years. Hearing then began to deteriorate and revision surgery showed disintegration of the prosthesis and a defect in the stapes footplate. Histological examination confirmed previous findings in porous polyethylene with multinucleated foreign body giant cells and breakdown of the material. PMID:10384839

  2. Free volume change of elongated polyethylene films studied using a positron probe microanalyzer

    NASA Astrophysics Data System (ADS)

    Oka, Toshitaka; Oshima, Nagayasu; Suzuki, Ryoichi; Uedono, Akira; Fujinami, Masanori; Kobayashi, Yoshinori

    2012-11-01

    Free volume change of low density polyethylene (LDPE) and high density polyethylene (HDPE) films upon mechanical deformation was microscopically investigated by positron probe microanalysis (PPMA). The ortho-positronium (o-Ps) lifetimes were gradually shortened by uniaxial deformation, indicative of shrinkage of the free volume. The o-Ps intensity for HDPE increased by deformation, whereas that for LDPE varied little. It suggests that destruction of crystallites plays an important role in the deformation of HDPE. PPMA is demonstrated to be a promising, powerful probe investigating free volume changes, at different local points subjected to different degrees of deformation, in elongated polymers.

  3. High-density grids for efficient data collection from multiple crystals

    PubMed Central

    Baxter, Elizabeth L.; Aguila, Laura; Alonso-Mori, Roberto; Barnes, Christopher O.; Bonagura, Christopher A.; Brehmer, Winnie; Brunger, Axel T.; Calero, Guillermo; Caradoc-Davies, Tom T.; Chatterjee, Ruchira; Degrado, William F.; Fraser, James S.; Ibrahim, Mohamed; Kern, Jan; Kobilka, Brian K.; Kruse, Andrew C.; Larsson, Karl M.; Lemke, Heinrik T.; Lyubimov, Artem Y.; Manglik, Aashish; McPhillips, Scott E.; Norgren, Erik; Pang, Siew S.; Soltis, S. M.; Song, Jinhu; Thomaston, Jessica; Tsai, Yingssu; Weis, William I.; Woldeyes, Rahel A.; Yachandra, Vittal; Yano, Junko; Zouni, Athina; Cohen, Aina E.

    2016-01-01

    Higher throughput methods to mount and collect data from multiple small and radiation-sensitive crystals are important to support challenging structural investigations using microfocus synchrotron beamlines. Furthermore, efficient sample-delivery methods are essential to carry out productive femtosecond crystallography experiments at X-ray free-electron laser (XFEL) sources such as the Linac Coherent Light Source (LCLS). To address these needs, a high-density sample grid useful as a scaffold for both crystal growth and diffraction data collection has been developed and utilized for efficient goniometer-based sample delivery at synchrotron and XFEL sources. A single grid contains 75 mounting ports and fits inside an SSRL cassette or uni-puck storage container. The use of grids with an SSRL cassette expands the cassette capacity up to 7200 samples. Grids may also be covered with a polymer film or sleeve for efficient room-temperature data collection from multiple samples. New automated routines have been incorporated into the Blu-Ice/DCSS experimental control system to support grids, including semi-automated grid alignment, fully automated positioning of grid ports, rastering and automated data collection. Specialized tools have been developed to support crystallization experiments on grids, including a universal adaptor, which allows grids to be filled by commercial liquid-handling robots, as well as incubation chambers, which support vapor-diffusion and lipidic cubic phase crystallization experiments. Experiments in which crystals were loaded into grids or grown on grids using liquid-handling robots and incubation chambers are described. Crystals were screened at LCLS-XPP and SSRL BL12-2 at room temperature and cryogenic temperatures. PMID:26894529

  4. High-density grids for efficient data collection from multiple crystals

    SciTech Connect

    Baxter, Elizabeth L.; Aguila, Laura; Alonso-Mori, Roberto; Barnes, Christopher O.; Bonagura, Christopher A.; Brehmer, Winnie; Brunger, Axel T.; Calero, Guillermo; Caradoc-Davies, Tom T.; Chatterjee, Ruchira; Degrado, William F.; Fraser, James S.; Ibrahim, Mohamed; Kern, Jan; Kobilka, Brian K.; Kruse, Andrew C.; Larsson, Karl M.; Lemke, Heinrik T.; Lyubimov, Artem Y.; Manglik, Aashish; McPhillips, Scott E.; Norgren, Erik; Pang, Siew S.; Soltis, S. M.; Song, Jinhu; Thomaston, Jessica; Tsai, Yingssu; Weis, William I.; Woldeyes, Rahel A.; Yachandra, Vittal; Yano, Junko; Zouni, Athina; Cohen, Aina E.

    2016-01-01

    Higher throughput methods to mount and collect data from multiple small and radiation-sensitive crystals are important to support challenging structural investigations using microfocus synchrotron beamlines. Furthermore, efficient sample-delivery methods are essential to carry out productive femtosecond crystallography experiments at X-ray free-electron laser (XFEL) sources such as the Linac Coherent Light Source (LCLS). To address these needs, a high-density sample grid useful as a scaffold for both crystal growth and diffraction data collection has been developed and utilized for efficient goniometer-based sample delivery at synchrotron and XFEL sources. A single grid contains 75 mounting ports and fits inside an SSRL cassette or uni-puck storage container. The use of grids with an SSRL cassette expands the cassette capacity up to 7200 samples. Grids may also be covered with a polymer film or sleeve for efficient room-temperature data collection from multiple samples. New automated routines have been incorporated into theBlu-Ice/DCSSexperimental control system to support grids, including semi-automated grid alignment, fully automated positioning of grid ports, rastering and automated data collection. Specialized tools have been developed to support crystallization experiments on grids, including a universal adaptor, which allows grids to be filled by commercial liquid-handling robots, as well as incubation chambers, which support vapor-diffusion and lipidic cubic phase crystallization experiments. Experiments in which crystals were loaded into grids or grown on grids using liquid-handling robots and incubation chambers are described. Crystals were screened at LCLS-XPP and SSRL BL12-2 at room temperature and cryogenic temperatures.

  5. High-density grids for efficient data collection from multiple crystals.

    PubMed

    Baxter, Elizabeth L; Aguila, Laura; Alonso-Mori, Roberto; Barnes, Christopher O; Bonagura, Christopher A; Brehmer, Winnie; Brunger, Axel T; Calero, Guillermo; Caradoc-Davies, Tom T; Chatterjee, Ruchira; Degrado, William F; Fraser, James S; Ibrahim, Mohamed; Kern, Jan; Kobilka, Brian K; Kruse, Andrew C; Larsson, Karl M; Lemke, Heinrik T; Lyubimov, Artem Y; Manglik, Aashish; McPhillips, Scott E; Norgren, Erik; Pang, Siew S; Soltis, S M; Song, Jinhu; Thomaston, Jessica; Tsai, Yingssu; Weis, William I; Woldeyes, Rahel A; Yachandra, Vittal; Yano, Junko; Zouni, Athina; Cohen, Aina E

    2016-01-01

    Higher throughput methods to mount and collect data from multiple small and radiation-sensitive crystals are important to support challenging structural investigations using microfocus synchrotron beamlines. Furthermore, efficient sample-delivery methods are essential to carry out productive femtosecond crystallography experiments at X-ray free-electron laser (XFEL) sources such as the Linac Coherent Light Source (LCLS). To address these needs, a high-density sample grid useful as a scaffold for both crystal growth and diffraction data collection has been developed and utilized for efficient goniometer-based sample delivery at synchrotron and XFEL sources. A single grid contains 75 mounting ports and fits inside an SSRL cassette or uni-puck storage container. The use of grids with an SSRL cassette expands the cassette capacity up to 7200 samples. Grids may also be covered with a polymer film or sleeve for efficient room-temperature data collection from multiple samples. New automated routines have been incorporated into the Blu-Ice/DCSS experimental control system to support grids, including semi-automated grid alignment, fully automated positioning of grid ports, rastering and automated data collection. Specialized tools have been developed to support crystallization experiments on grids, including a universal adaptor, which allows grids to be filled by commercial liquid-handling robots, as well as incubation chambers, which support vapor-diffusion and lipidic cubic phase crystallization experiments. Experiments in which crystals were loaded into grids or grown on grids using liquid-handling robots and incubation chambers are described. Crystals were screened at LCLS-XPP and SSRL BL12-2 at room temperature and cryogenic temperatures. PMID:26894529

  6. High-density grids for efficient data collection from multiple crystals

    DOE PAGESBeta

    Baxter, Elizabeth L.; Aguila, Laura; Alonso-Mori, Roberto; Barnes, Christopher O.; Bonagura, Christopher A.; Brehmer, Winnie; Brunger, Axel T.; Calero, Guillermo; Caradoc-Davies, Tom T.; Chatterjee, Ruchira; et al

    2015-11-03

    Higher throughput methods to mount and collect data from multiple small and radiation-sensitive crystals are important to support challenging structural investigations using microfocus synchrotron beamlines. Furthermore, efficient sample-delivery methods are essential to carry out productive femtosecond crystallography experiments at X-ray free-electron laser (XFEL) sources such as the Linac Coherent Light Source (LCLS). To address these needs, a high-density sample grid useful as a scaffold for both crystal growth and diffraction data collection has been developed and utilized for efficient goniometer-based sample delivery at synchrotron and XFEL sources. A single grid contains 75 mounting ports and fits inside an SSRL cassettemore » or uni-puck storage container. The use of grids with an SSRL cassette expands the cassette capacity up to 7200 samples. Grids may also be covered with a polymer film or sleeve for efficient room-temperature data collection from multiple samples. New automated routines have been incorporated into theBlu-Ice/DCSSexperimental control system to support grids, including semi-automated grid alignment, fully automated positioning of grid ports, rastering and automated data collection. Specialized tools have been developed to support crystallization experiments on grids, including a universal adaptor, which allows grids to be filled by commercial liquid-handling robots, as well as incubation chambers, which support vapor-diffusion and lipidic cubic phase crystallization experiments. Experiments in which crystals were loaded into grids or grown on grids using liquid-handling robots and incubation chambers are described. As a result, crystals were screened at LCLS-XPP and SSRL BL12-2 at room temperature and cryogenic temperatures.« less

  7. On-chip high density droplet-on-template (DOT) array

    NASA Astrophysics Data System (ADS)

    Kim, Jitae; Song, Simon

    2015-01-01

    In this report, we present a new method for generating a high-density (2D) droplet array using double-layered polydimethylsiloxane (PDMS) templates containing honeycomb microwells. Without external flow control, a droplet-on-template (DOT) was created by utilizing capillary forces associated with the interfacial tension between the aqueous and oil phases. The DOT process involved three simple steps: (1) vacuum-assisted filling of microwells; (2) excess water removal; and (3) covering the droplet array with oil. To demonstrate the concept of the DOT, we generated spherical water droplets 147, 191, 238, 326 and 405 μm in diameter from corresponding microwells with lengths of 200, 300, 400, 600 and 800 μm, respectively and a height of 76 μm (up to ~10,000 droplets on a template 25  ×  25 mm). Two important factors, including the aspect ratio (height-to-length ratio) of the microwell and the interfacial tension of the two phases, were investigated to understand how those factors affect the shape of the droplets (‘sphere’ or ‘dome’). All the droplets were spherical up to an aspect ratio of 0.55. The droplets were dome-shaped for aspect ratios above 0.82. For a 1 mM sodium dodecyl sulfate (SDS) solution, the use of mineral oil (which had the highest interfacial tension studied) produced spherical droplets, but dome-shaped droplets were produced by corn oil and oleic acid.

  8. Fabrication, Micro-structural Analysis, and Mechanical Testing of High Density Polymeric Foam

    NASA Astrophysics Data System (ADS)

    Marks, Trevor Gustov

    Foams, or what are often called cellular solids, are some of the most widely used materials in the modern era. In general, foam is a porous substance formed by the introduction of gas filled pores into condensed matter; the result is typically a light weight substance with properties related to the base (non-porous) medium. Applications of foams include: vibration dampening, energy mitigation (such as packaging and bike helmets), insulation, filtration, and flotation. The focus of this work is on the properties of flexible elastomeric foam of high relative-density. The bulk of existing literature on elastomeric foam is concerned with foam of low relative-density (ratio of the foam density to the density of the material from which the foam is formed ≤ 0.1). The relationship between the micro-structure of high relative-density foam and its mechanical response has, in large part, not been subjected to systematic investigation heretofore. The present work examines how the micro-structural features of pore shape, size, and location affect the macro-structural response of relative high density foam to compressive loading. In order to carry out this study, methods were developed and employed to control a foam's micro-structure, and hence its mechanical response, with the use of temporary pore forming particles and micron scale inclusions. Advanced microscopy techniques were used to observe, in situ, the evolution of a foam's micro-structure under compressive loading, and the results were correlated with the evolution of the foam's stress - strain response. Additionally, quantitative methods were developed and employed to describe numerically the foam's micro-structural features, such as: (i), pore shape, (ii), pore size, and (iii), the arrangement of the pores with respect to each other. Numerous foams were produced, tested, and subjected to the

  9. High-density grids for efficient data collection from multiple crystals

    SciTech Connect

    Baxter, Elizabeth L.; Aguila, Laura; Alonso-Mori, Roberto; Barnes, Christopher O.; Bonagura, Christopher A.; Brehmer, Winnie; Brunger, Axel T.; Calero, Guillermo; Caradoc-Davies, Tom T.; Chatterjee, Ruchira; Degrado, William F.; Fraser, James S.; Ibrahim, Mohamed; Kern, Jan; Kobilka, Brian K.; Kruse, Andrew C.; Larsson, Karl M.; Lemke, Heinrik T.; Lyubimov, Artem Y.; Manglik, Aashish; McPhillips, Scott E.; Norgren, Erik; Pang, Siew S.; Soltis, S. M.; Song, Jinhu; Thomaston, Jessica; Tsai, Yingssu; Weis, William I.; Woldeyes, Rahel A.; Yachandra, Vittal; Yano, Junko; Zouni, Athina; Cohen, Aina E.

    2015-11-03

    Higher throughput methods to mount and collect data from multiple small and radiation-sensitive crystals are important to support challenging structural investigations using microfocus synchrotron beamlines. Furthermore, efficient sample-delivery methods are essential to carry out productive femtosecond crystallography experiments at X-ray free-electron laser (XFEL) sources such as the Linac Coherent Light Source (LCLS). To address these needs, a high-density sample grid useful as a scaffold for both crystal growth and diffraction data collection has been developed and utilized for efficient goniometer-based sample delivery at synchrotron and XFEL sources. A single grid contains 75 mounting ports and fits inside an SSRL cassette or uni-puck storage container. The use of grids with an SSRL cassette expands the cassette capacity up to 7200 samples. Grids may also be covered with a polymer film or sleeve for efficient room-temperature data collection from multiple samples. New automated routines have been incorporated into theBlu-Ice/DCSSexperimental control system to support grids, including semi-automated grid alignment, fully automated positioning of grid ports, rastering and automated data collection. Specialized tools have been developed to support crystallization experiments on grids, including a universal adaptor, which allows grids to be filled by commercial liquid-handling robots, as well as incubation chambers, which support vapor-diffusion and lipidic cubic phase crystallization experiments. Experiments in which crystals were loaded into grids or grown on grids using liquid-handling robots and incubation chambers are described. As a result, crystals were screened at LCLS-XPP and SSRL BL12-2 at room temperature and cryogenic temperatures.

  10. Discoidal bilayer structure of nascent high density lipoproteins from perfused rat liver.

    PubMed Central

    Hamilton, R L; Williams, M C; Fielding, C J; Havel, R J

    1976-01-01

    Rat livers were perfused for 6 h without added plasma proteins using washed erythrocytes and buffer in a recirculating system. An inhibitor to the enzyme lecithin-cholesterol acyltransferase (5,5'-dithionitrobenzoic acid) was added in some experiments to prevent modification of substrate-lipids contained in secreted lipoproteins. The inhibitor did not detectably alter hepatic ultrastructure or gas exchange, but it inhibited the secreted lecithin-cholesterol acyltransferase by more than 85%. Very low density lipoproteins in perfusate were unaltered but the high density lipoproteins obtained from livers perfused with the inhibitor appeared disk-shaped in negative stain by electron microscopy with a mean edge thickness of 46 +/- 5 A and a mean diameter of 190 +/- 25 A. The high density lipoproteins were composed predominantly of polar lipids and protein with only small amounts of cholesteryl esters and triglycerides. The major apoprotein of these discoidal fractions had the same electrophoretic mobility as the arginine-rich apoprotein, whereas plasma high density lipoproteins contained mainly the A-I approtein. In all these respects the discoidal perfusate high density lipoproteins closely resemble those found in human plasma which is deficient in lecithin-cholesterol acyltransferase. Perfusate high density lipoproteins obtained in the absence of the enzyme inhibitor more closely resembled plasma high density lipoproteins in chemical composition (content of cholesteryl esters and apoproteins) and in electron microscopic appearance. Purified lecithin-cholesterol acyltransferase synthesized cholesteryl esters at a substantially faster rate from substrate lipids of perfusate high density lipoproteins than those from plasma. The discoidal high density lipoproteins were the best substrate for this reaction. Thin sections of plasma high density lipoproteins indicated a spherical particle whereas discoidal high density lipoproteins stained with the characteristic trilaminar

  11. Nanostructure and thermal properties of melt compounded PE/clay nanocomposites filled with an organosilylated montmorillonite

    SciTech Connect

    Scarfato, Paola; Incarnato, Loredana; Di Maio, Luciano; Dittrich, Bettina; Niebergall, Ute; Böhning, Martin; Schartel, Bernhard

    2015-12-17

    In this work we report on the functionalization of a natural sodium montmorillonite (MMT) with (3-glycidyloxypropyl)trimethoxysilane by a silylation procedure and on its use as nanofiller in melt compounding of polyethylene nanocomposites. The obtained organosilylated clay showed higher interlayer spacing than the original MMT and higher thermal stability with respect to most of commercial organoclays modified with alkylammonium salts. Its addition (at 5wt%) to two different polyethylene matrices (a low density polyethylene, LDPE, and a high density polyethylene, HDPE), processed in a pilot-scale twin-screw extruder, allowed to produce hybrids with nanoscale dispersion of the filler, as demonstrated by X-ray diffraction. Thermogravimetric and differential scanning thermal analyses point out that the obtained nanocomposites do not show noticeable changes in the thermal behavior of both LDPE and HDPE, even if a slight reduction in the overall bulk crystallinity was observed in presence of the nanofillers.

  12. Nanostructure and thermal properties of melt compounded PE/clay nanocomposites filled with an organosilylated montmorillonite

    NASA Astrophysics Data System (ADS)

    Scarfato, Paola; Incarnato, Loredana; Di Maio, Luciano; Dittrich, Bettina; Niebergall, Ute; Böhning, Martin; Schartel, Bernhard

    2015-12-01

    In this work we report on the functionalization of a natural sodium montmorillonite (MMT) with (3-glycidyloxypropyl)trimethoxysilane by a silylation procedure and on its use as nanofiller in melt compounding of polyethylene nanocomposites. The obtained organosilylated clay showed higher interlayer spacing than the original MMT and higher thermal stability with respect to most of commercial organoclays modified with alkylammonium salts. Its addition (at 5wt%) to two different polyethylene matrices (a low density polyethylene, LDPE, and a high density polyethylene, HDPE), processed in a pilot-scale twin-screw extruder, allowed to produce hybrids with nanoscale dispersion of the filler, as demonstrated by X-ray diffraction. Thermogravimetric and differential scanning thermal analyses point out that the obtained nanocomposites do not show noticeable changes in the thermal behavior of both LDPE and HDPE, even if a slight reduction in the overall bulk crystallinity was observed in presence of the nanofillers.

  13. Flying-plate detonator using a high-density high explosive

    DOEpatents

    Stroud, John R.; Ornellas, Donald L.

    1988-01-01

    A flying-plate detonator containing a high-density high explosive such as benzotrifuroxan (BTF). The detonator involves the electrical explosion of a thin metal foil which punches out a flyer from a layer overlying the foil, and the flyer striking a high-density explosive pellet of BTF, which is more thermally stable than the conventional detonator using pentaerythritol tetranitrate (PETN).

  14. High-density renal cysts in autosomal dominant polycystic kidney disease demonstrated by CT

    SciTech Connect

    Levine, E.; Grantham, J.J.

    1985-02-01

    Unenhanced abdominal CT scans of 35 patients with autosomal dominant polycystic kidney disease (ADPKD) showed multiple high-density (58-84 HU) renal cysts in 42.9% of patients, occasional high-density cysts in 25.7%, and no high-density cysts in 31.4%. These high-density cysts were usually subcapsular and were more frequent in patients with markedly enlarged kidneys and flank pain at the time of CT. Follow-up CT often showed a reduction in cyst densities, although some cysts developed mural calcification and calcification of their contents. Renal carcinomas occur rarely in ADPKD and may occasionally be hyperdense. However, high-density cysts may usually be distinguished from carcinomas on CT by their smooth contours, sharp interfaces with renal parenchyma, homogeneity, and lack of contrast enhancement.

  15. Photolithographic Synthesis of High-Density DNA and RNA Arrays on Flexible, Transparent, and Easily Subdivided Plastic Substrates.

    PubMed

    Holden, Matthew T; Carter, Matthew C D; Wu, Cheng-Hsien; Wolfer, Jamison; Codner, Eric; Sussman, Michael R; Lynn, David M; Smith, Lloyd M

    2015-11-17

    The photolithographic fabrication of high-density DNA and RNA arrays on flexible and transparent plastic substrates is reported. The substrates are thin sheets of poly(ethylene terephthalate) (PET) coated with cross-linked polymer multilayers that present hydroxyl groups suitable for conventional phosphoramidite-based nucleic acid synthesis. We demonstrate that by modifying array synthesis procedures to accommodate the physical and chemical properties of these materials, it is possible to synthesize plastic-backed oligonucleotide arrays with feature sizes as small as 14 μm × 14 μm and feature densities in excess of 125 000/cm(2), similar to specifications attainable using rigid substrates such as glass or glassy carbon. These plastic-backed arrays are tolerant to a wide range of hybridization temperatures, and improved synthetic procedures are described that enable the fabrication of arrays with sequences up to 50 nucleotides in length. These arrays hybridize with S/N ratios comparable to those fabricated on otherwise identical arrays prepared on glass or glassy carbon. This platform supports the enzymatic synthesis of RNA arrays and proof-of-concept experiments are presented showing that the arrays can be readily subdivided into smaller arrays (or "millichips") using common laboratory-scale laser cutting tools. These results expand the utility of oligonucleotide arrays fabricated on plastic substrates and open the door to new applications for these important bioanalytical tools. PMID:26494264

  16. 21 CFR 177.1615 - Polyethylene, fluorinated.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyethylene, fluorinated. 177.1615 Section 177... Contact Surfaces § 177.1615 Polyethylene, fluorinated. Fluorinated polyethylene, identified in paragraph... prescribed conditions: (a) Fluorinated polyethylene food-contact articles are produced by modifying...

  17. 21 CFR 177.1620 - Polyethylene, oxidized.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyethylene, oxidized. 177.1620 Section 177.1620... Contact Surfaces § 177.1620 Polyethylene, oxidized. Oxidized polyethylene identified in paragraph (a) of... following prescribed conditions: (a) Oxidized polyethylene is the basic resin produced by the mild...

  18. Pressurized gas filled tendons

    SciTech Connect

    Silcox, W. H.

    1985-06-04

    Pressurized gas filled tubular tendons provide a means for detecting leaks therein. Filling the tendon with a gaseous fluid provides increased buoyancy and reduces the weight supported by the buoyant structure. The use of a corrosion inhibiting gaseous fluid reduces the corrosion of the interior tendon wall.

  19. High-temperature compatibility between liquid metal as PWR fuel gap filler and stainless steel and high-density concrete

    NASA Astrophysics Data System (ADS)

    Wongsawaeng, Doonyapong; Jumpee, Chayanit; Jitpukdee, Manit

    2014-08-01

    In conventional nuclear fuel rods for light-water reactors, a helium-filled as-fabricated gap between the fuel and the cladding inner surface accommodates fuel swelling and cladding creep down. Because helium exhibits a very low thermal conductivity, it results in a large temperature rise in the gap. Liquid metal (LM; 1/3 weight portion each of lead, tin, and bismuth) has been proposed to be a gap filler because of its high thermal conductivity (∼100 times that of He), low melting point (∼100 °C), and lack of chemical reactivity with UO2 and water. With the presence of LM, the temperature drop across the gap is virtually eliminated and the fuel is operated at a lower temperature at the same power output, resulting in safer fuel, delayed fission gas release and prevention of massive secondary hydriding. During normal reactor operation, should an LM-bonded fuel rod failure occurs resulting in a discharge of liquid metal into the bottom of the reactor pressure vessel, it should not corrode stainless steel. An experiment was conducted to confirm that at 315 °C, LM in contact with 304 stainless steel in the PWR water chemistry environment for up to 30 days resulted in no observable corrosion. Moreover, during a hypothetical core-melt accident assuming that the liquid metal with elevated temperature between 1000 and 1600 °C is spread on a high-density concrete basement of the power plant, a small-scale experiment was performed to demonstrate that the LM-concrete interaction at 1000 °C for as long as 12 h resulted in no penetration. At 1200 °C for 5 h, the LM penetrated a distance of ∼1.3 cm, but the penetration appeared to stop. At 1400 °C the penetration rate was ∼0.7 cm/h. At 1600 °C, the penetration rate was ∼17 cm/h. No corrosion based on chemical reactions with high-density concrete occurred, and, hence, the only physical interaction between high-temperature LM and high-density concrete was from tiny cracks generated from thermal stress. Moreover

  20. Filling Tanks with Hydrazine

    NASA Astrophysics Data System (ADS)

    Krueger, K.

    2004-10-01

    At the Hydrazine workshop in 2002 in Noordwijk several presentations dealt with the filling of satellite tanks. I was a bit surprised about the amount of manpower that is needed for this work. But I saw the same during the filling of the SCA system tanks some years ago in Trauen/Germany. I want to present the work flow of filling RESUS Hydrazine tanks. This bladder tanks have a capacity of 64 litres and are similar to some of the satellite tanks. We fill this tanks 25 to 50 times a year. Although the specifications are not exactly the same as those for satellite tank filling, it might be interesting to see how this work can be done half-automatically, because handling with Hydrazine is not a nice job, and the faster it goes, the better.

  1. Porous polyethylene implants in facial reconstruction: Outcome and complications.

    PubMed

    Ridwan-Pramana, Angela; Wolff, Jan; Raziei, Ashkan; Ashton-James, Claire E; Forouzanfar, Tymour

    2015-10-01

    The aim of the present study was to assess the indications, results and complications of patients treated with porous polyethylene (Medpor(®)) implants in the Department of Oral and Maxillofacial Surgery of VU Medical Centre, Amsterdam over 17 years. A total of 69 high-density porous polyethylene implants (Medpor(®) Biomaterial; Porex Surgical, Newman, GA) were used in forty patients (22 males, 18 females). All patients were analysed for gender, age, diagnosis, indications for surgery, follow-up period and postoperative complications. A mean age of 34.1 years was observed. The main reason for implant surgery was post-traumatic functional impairment (27.5%). Most implants were placed at the mandibular angel and the orbital floor. Unsatisfactory appearance scored the highest in postoperative complications (10.1%) followed by infection rate (7.2%). Comparing the number of implants placed over the years and the incidence of complications, makes the overall complications rate of porous polyethylene very low. A consensus about antibiotic prophylaxis is needed. The objective measurements in patient satisfaction and proper implant design would be of great use. PMID:26276064

  2. Polyethylene degradation in a coal liquefaction environment

    SciTech Connect

    Thompson, R.L.; Rothenberger, K.S.; Cugini, A.V.

    1996-12-31

    The coprocessing of coal with waste materials such as plastic has shown promise as an economical means to recover the inherent value of the wastes while producing useful products. Polyethylene (PE) is one of the dominant plastics on the market; recent statistics indicate that low- and high-density PE together make up about half of all municipal plastic waste. However, recent studies have shown that PE is also among the most difficult plastics to convert in the traditional liquefaction environment, particularly in the presence of coal and/or donor solvents. The coal liquefaction environment is quite different than that encountered during thermal or catalytic pyrolysis. In this paper, a novel analytical method has been developed to recover incompletely reacted PE from coprocessing product streams. Once separated from the coal-derived material, gel permeation chromatography (GPC) was applied to the recovered material to ascertain the nature of the changes that occurred to the PE upon processing in a bench-scale continuous liquefaction unit. Also, 1-L semi-batch reactions were performed to investigate the reactivity of PE and coal-PE mixtures as a function of temperature.

  3. Polyethylene degradation in a coal liquefaction environment

    SciTech Connect

    Rothenberger, K.S.; Cugini, A.V.; Thompson, R.L.

    1996-12-31

    The coprocessing of coal with waste materials such as plastic has shown promise as an economical means to recover the inherent value of the wastes while producing useful products. Polyethylene (PE) is one of the dominant plastic materials; recent statistics indicate that low- and high-density PE together make up about half of all municipal plastic waste. The degradation of PE in a pyrolysis environment has been well studied, and pyrolysis-based methods for the conversion of PE to fuels have been published. However, recent studies have shown that PE is among the most difficult plastics to convert in the traditional liquefaction environment, particularly in the presence of coal and/or donor solvents. The coal liquefaction environment is quite different than that encountered during thermal or catalytic pyrolysis. Understanding the degradation behavior of PE in the liquefaction environment is important to development of a successful scheme for coprocessing coal with plastics. In this paper, a novel analytical method has been developed to recover incompletely reacted PE from coprocessing product streams. Once separated from the coal-derived material, gel permeation chromatography, a conventional polymer characterization technique, was applied to the recovered material to ascertain the nature of the changes that occurred to the PE upon processing in a bench-scale continuous liquefaction unit. In a separate phase of the project, 1-L semi-batch reactions were performed to investigate the reactivity of PE and coal-PE mixtures as a function of temperature.

  4. High density harp for SSCL linac. [Suerconducting Super Collider Laboratory (SSCL)

    SciTech Connect

    Fritsche, C.T.; Krogh, M.L. . Bendix Kansas City Div.); Crist, C.E. )

    1993-05-01

    AlliedSignal Inc., Kansas City Division, and the Superconducting Super Collider Laboratory (SSCL) are collaboratively developing a high density harp for the SSCL linac. This harp is designed using hybrid microcircuit (HMC) technology to obtain a higher wire density than previously available. The developed harp contains one hundred twenty-eight 33-micron-diameter carbon wires on 0.38-mm centers. The harp features an onboard broken wire detection circuit. Carbon wire preparation and attachment processes were developed. High density surface mount connectors were located. The status of high density harp development will be presented along with planned future activities.

  5. High-density lipoprotein cholesterol on a roller coaster: where will the ride end?

    PubMed

    Kronenberg, Florian

    2016-04-01

    Bowe et al. report an association between low high-density lipoprotein cholesterol concentrations and various incident chronic kidney disease end points in a cohort of almost 2 million US veterans followed for 9 years. These impressive data should be a starting point for further investigations including genetic epidemiologic investigations as well as post hoc analyses of interventional trials that target high-density lipoprotein cholesterol and, finally, studies that focus on the functionality of high-density lipoprotein particles. PMID:26994572

  6. Mechanical, rheological, and bioactivity properties of ultra high-molecular-weight polyethylene bioactive composites containing polyethylene glycol and hydroxyapatite.

    PubMed

    Ahmad, Mazatusziha; Uzir Wahit, Mat; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

    2012-01-01

    Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis. PMID:22666129

  7. Mechanical, Rheological, and Bioactivity Properties of Ultra High-Molecular-Weight Polyethylene Bioactive Composites Containing Polyethylene Glycol and Hydroxyapatite

    PubMed Central

    Ahmad, Mazatusziha; Wahit, Mat Uzir; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

    2012-01-01

    Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis. PMID:22666129

  8. Urethane-based stabilizers for radiation-crosslinked polyethylene. [Electron beams

    SciTech Connect

    Shkolnik, S.; Rajbenbach, L.A.

    1982-11-01

    Unsaturated urethane-based stabilizers for use in radiation-crosslinked polyethylene were synthesized. Aromatic amine moieties were attached to allylic and acrylic monomers by means of aromatic or aliphatic diisocyanates. The synthesized stabilizers were incorporated in high-density polyethylene films which were subjected to electron beam irradiation. The oxidative stability of the films prior to and after extraction was determined by DTA in the temperature range 185-210/sup 0/C and compared with samples treated with commercial amine-bearing antioxidants. Tensile strength and gel content were also determined. Best results were obtained with a stabilizer prepared from equimolecular amounts of allyl alcohol, tolylene-2,4-diisocyanate and N-phenyl-1,4-phenylenediamine. Estimated lifetimes at 70/sup 0/C of stabilized irradiated polyethylene samples were calculated.

  9. High-density interconnect substrates and device packaging using conductive composites

    NASA Astrophysics Data System (ADS)

    Gandhi, Pradeep; Gallagher, Catherine; Matijasevic, Goran

    1998-02-01

    High-end printed circuit board manufacturing technology is receiving increasing attention due to higher functionality in smaller form factors. This is evident from the industry efforts to produced reliable microvias and related trace features to pack as much circuit density as possible. Cost, density and performance requirements have prodded entry into a market that was mainly reserved for ceramic and molded packages for the last forty years. To successfully meet the demanding specifications of this market segment, a worldwide effort is underway for the development of new materials, processes and equipment. A novel base technology that is applicable to most of the major packaging and redistribution elements in an electronic module is presented.High density multilayer circuits with landless blind and buried vias can be fabricated by filling the conductor paste into photoimaged dielectrics and thermally processing it at a relatively lower temperature. Via layers are prepared directly on the inherently planarized circuit layer in an identical fashion. Because these composite materials are applied in an additive fabrication method, metal substrates can be employed for high thermal dissipation and excellent CTE control over a wide temperature range. The conductor material is based on interpenetrating polymer and metal networks that are formed in situ from metal particles and a thermosetting flux/binder. The metal network is formed when the alloy particles melt and react with adjacent high melting point metal particle. Interaction also occurs between the alloy particles and pad, lead or previous trace metallizations provided they are solderable by alloys of tin. The new alloy composition created by the interdiffusion process within the bulk material has a higher melting point than the original alloy and thus solidifies immediately upon formation. This metallurgical reaction, known as transient liquid phase sintering, is facilitated by the polymer mixture. INtegration of

  10. Breast Cancer Patients with High Density Mammograms Do Not Have Increased Risk of Death

    MedlinePlus

    ... News Releases News Release Thursday, September 6, 2012 Breast cancer patients with high density mammograms do not have ... is a marker of increased risk of developing breast cancer, does not seem to increase the risk of ...

  11. Getting a prescription filled

    MedlinePlus

    ... to get prescription filled; Pharmacy - mail order; Pharmacy - internet; Types of pharmacies ... stored at certain temperatures at a local pharmacy. INTERNET (ONLINE) PHARMACIES Internet pharmacies can be used for ...

  12. Pyrotechnic filled molding powder

    DOEpatents

    Hartzel, Lawrence W.; Kettling, George E.

    1978-01-01

    The disclosure relates to thermosetting molding compounds and more particularly to a pyrotechnic filled thermosetting compound comprising a blend of unfilled diallyl phthalate molding powder and a pyrotechnic mixture.

  13. High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

    DOEpatents

    Freitas, Barry L.

    1998-01-01

    An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver>4kW/cm2 of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources.

  14. High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

    DOEpatents

    Freitas, B.L.

    1998-10-27

    An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver > 4kW/cm{sup 2} of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources. 13 figs.

  15. Post-irradiation effects in polyethylenes irradiated under various atmospheres

    NASA Astrophysics Data System (ADS)

    Suljovrujic, E.

    2013-08-01

    If a large amount of polymer free radicals remain trapped after irradiation of polymers, the post-irradiation effects may result in a significant alteration of physical properties during long-term shelf storage and use. In the case of polyethylenes (PEs) some failures are attributed to the post-irradiation oxidative degradation initiated by the reaction of residual free radicals (mainly trapped in crystal phase) with oxygen. Oxidation products such as carbonyl groups act as deep traps and introduce changes in carrier mobility and significant deterioration in the PEs electrical insulating properties. The post-irradiation behaviour of three different PEs, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) was studied; previously, the post-irradiation behaviour of the PEs was investigated after the irradiation in air (Suljovrujic, 2010). In this paper, in order to investigate the influence of different irradiation media on the post-irradiation behaviour, the samples were irradiated in air and nitrogen gas, to an absorbed dose of 300 kGy. The annealing treatment of irradiated PEs, which can substantially reduce the concentration of free radicals, is used in this study, too. Dielectric relaxation behaviour is related to the difference in the initial structure of PEs (such as branching, crystallinity etc.), to the changes induced by irradiation in different media and to the post-irradiation changes induced by storage of the samples in air. Electron spin resonance (ESR), differential scanning calorimetry (DSC), infra-red (IR) spectroscopy and gel measurements were used to determine the changes in the free radical concentration, crystal fraction, oxidation and degree of network formation, respectively.

  16. Electromagnetic Characteristics of Thin Polyethylene-Carbon-Polyethylene Films

    NASA Astrophysics Data System (ADS)

    Volynets, N. I.; Lyubimov, A. G.; Plyushch, A. O.; Poddubskaya, O. G.; Kuzhir, P. P.; Korovin, E. Yu.; Suslyaev, V. I.; Macutkevic, J.; Pikutskaya, E. S.; Baturkin, S. A.; Klochkov, A. Ya.

    2015-09-01

    A method of manufacturing a polyethylene - expanded carbon - polyethylene layered structures which allows thin (down to 90 μm) and flexible sandwiches to be easily made, is suggested. The electromagnetic properties of the manufactured composite materials at frequencies from 1 MHz to 3 GHz, 26-37.5 GHz, and 0.1-1.4 THz are analyzed. It is established that the material so obtained is opaque for the Ka microwave band due to high reflectivity (96-97%), does not transmit electromagnetic radiation of the terahertz range, has a high conductivity (up to 1 S/m) in the frequency range from 1 MHz to 1 GHz, and retains the main physical polyethylene properties (light weight, elasticity, and flexibility).

  17. Evaluating fibrous polyethylene terephthalate (PET) and cellulose as components for soilless substrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this work was to test the suitability of FiberFill, a synthetic fiber made of polyethylene terephthalate, and Tencel, a cellulose-based fiber, as growing mix components by evaluating the growth of a variety of floriculture crops using substrates containing different proportions of t...

  18. Evaluating Performance and Stability of Polyethylene Terephthalate (PET) and Cellulose Polymer as Soilless Mix Components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the U.S., concerns over the long-term sustainability of peat, perlite, and other media components have led to searches for alternative materials. FiberFill, a synthetic fiber made of recyclable polyethylene terephthalate, and Tencel, a cellulose fiber, are new materials with potential as substra...

  19. Degradable polyethylene: fantasy or reality.

    PubMed

    Roy, Prasun K; Hakkarainen, Minna; Varma, Indra K; Albertsson, Ann-Christine

    2011-05-15

    Plastic waste disposal is one of the serious environmental issues being tackled by our society today. Polyethylene, particularly in packaging films, has received criticism as it tends to accumulate over a period of time, leaving behind an undesirable visual footprint. Degradable polyethylene, which would enter the eco-cycle harmlessly through biodegradation would be a desirable solution to this problem. However, the "degradable polyethylene" which is presently being promoted as an environmentally friendly alternative to the nondegradable counterpart, does not seem to meet this criterion. This article reviews the state of the art on the aspect of degradability of polyethylene containing pro-oxidants, and more importantly the effect these polymers could have on the environment in the long run. On exposure to heat, light, and oxygen, these polymers disintegrate into small fragments, thereby reducing or increasing the visual presence. However, these fragments can remain in the environment for prolonged time periods. This article also outlines important questions, particularly in terms of time scale of complete degradation, environmental fate of the polymer residues, and possible accumulation of toxins, the answers to which need to be established prior to accepting these polymers as environmentally benign alternatives to their nondegradable equivalents. It appears from the existing literature that our search for biodegradable polyethylene has not yet been realized. PMID:21495645

  20. High density physical mapping of chromosome 3p by hybridization of somatic cell hybrid derived Alu-PCR products

    SciTech Connect

    Shearman, A.M.; Andresen, J.M.; Aburatani, H.

    1994-09-01

    We have produced high density physical maps covering most of chromosome 3 using a hybridization-based approach to YAC isolation and contig assembly. The strategy has been to use a well characterized panel of somatic cell hybrids to generate probe sets distributed across the chromosome. From each of 50 somatic cell hybrids, a library of {approximately}100-600 cloned Alu-PCR products was isolated and Alu-PCR inserts from the full set of clones was spotted at high density on nylon membranes. Representative sets of unique clones from most of the hybrids were used to screen {approximately}16 genome equivalents of CEPH YACs by hybridization. These results, combined with our previous results and data from CEPH, produced contigs covering most of the chromosomes. The use of somatic cell hybrid-derived probe sets allowed easy integration of contigs with physical mapping boundaries defined by the somatic cell hybrids. We will describe various Alu-PCR strategies subsequently used to achieve closure, including successful identification of Alu-PCR products from the spotted set which lie in regions not previously covered by YAC contigs and use of Alu-PCR walking strategies to fill gaps and confirm tentative linkages. Our basic YAC screening methodology allows one individual to screen {approximately}16 genome equivalents of CEPH YACs with 96 probes/week at a material cost of less than $1 per locus. We have now mapped >2,200 loci on chromosome 3, with average interlocus distances of {approximately}50-100 kb over large regions. Alu-PCR-defined loci spaced along the chromosome at regular intervals are being converted to STSs. Our results indicate that use of a hybridization-based approach to physical mapping constitutes an efficient, accurate, high throughput method for isolating YACs and assembling YAC contigs.

  1. 21 CFR 177.1610 - Polyethylene, chlorinated.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... chlorination of polyethylene conforming to the density, maximum n-hexane extractable fraction, and maximum... polyethylene is limited to use only as a modifier admixed at levels not exceeding 15 weight percent in...

  2. Loose-fill insulations

    SciTech Connect

    1995-05-01

    Whether you are increasing the insulation levels in your current home or selecting insulation for a new home, choosing the right insulation material can be challenging. Fibrous loose-fill insulations such as cellulose, fiberglass, and rock wool are options you may wish to consider. This publication will introduce you to these materials--what they are, how they are applied, how they compare with each other, and other considerations regarding their use--so that you can decide whether loose fills are right for your home.

  3. SNP-based high density genetic map and mapping of btwd1 dwarfing gene in barley

    PubMed Central

    Ren, Xifeng; Wang, Jibin; Liu, Lipan; Sun, Genlou; Li, Chengdao; Luo, Hong; Sun, Dongfa

    2016-01-01

    A high-density linkage map is a valuable tool for functional genomics and breeding. A newly developed sequence-based marker technology, restriction site associated DNA (RAD) sequencing, has been proven to be powerful for the rapid discovery and genotyping of genome-wide single nucleotide polymorphism (SNP) markers and for the high-density genetic map construction. The objective of this research was to construct a high-density genetic map of barley using RAD sequencing. 1894 high-quality SNP markers were developed and mapped onto all seven chromosomes together with 68 SSR markers. These 1962 markers constituted a total genetic length of 1375.8 cM and an average of 0.7 cM between adjacent loci. The number of markers within each linkage group ranged from 209 to 396. The new recessive dwarfing gene btwd1 in Huaai 11 was mapped onto the high density linkage maps. The result showed that the btwd1 is positioned between SNP marks 7HL_6335336 and 7_249275418 with a genetic distance of 0.9 cM and 0.7 cM on chromosome 7H, respectively. The SNP-based high-density genetic map developed and the dwarfing gene btwd1 mapped in this study provide critical information for position cloning of the btwd1 gene and molecular breeding of barley. PMID:27530597

  4. SNP-based high density genetic map and mapping of btwd1 dwarfing gene in barley.

    PubMed

    Ren, Xifeng; Wang, Jibin; Liu, Lipan; Sun, Genlou; Li, Chengdao; Luo, Hong; Sun, Dongfa

    2016-01-01

    A high-density linkage map is a valuable tool for functional genomics and breeding. A newly developed sequence-based marker technology, restriction site associated DNA (RAD) sequencing, has been proven to be powerful for the rapid discovery and genotyping of genome-wide single nucleotide polymorphism (SNP) markers and for the high-density genetic map construction. The objective of this research was to construct a high-density genetic map of barley using RAD sequencing. 1894 high-quality SNP markers were developed and mapped onto all seven chromosomes together with 68 SSR markers. These 1962 markers constituted a total genetic length of 1375.8 cM and an average of 0.7 cM between adjacent loci. The number of markers within each linkage group ranged from 209 to 396. The new recessive dwarfing gene btwd1 in Huaai 11 was mapped onto the high density linkage maps. The result showed that the btwd1 is positioned between SNP marks 7HL_6335336 and 7_249275418 with a genetic distance of 0.9 cM and 0.7 cM on chromosome 7H, respectively. The SNP-based high-density genetic map developed and the dwarfing gene btwd1 mapped in this study provide critical information for position cloning of the btwd1 gene and molecular breeding of barley. PMID:27530597

  5. Characterization of high density lipoproteins in patients heterozygous for Tangier disease.

    PubMed Central

    Assmann, G; Simantke, O; Schaefer, H E; Smootz, E

    1977-01-01

    In this study a large family group affectd with Tangier disease has been investigated. Besides two homozygous propositi, several heterozygous patients have been identified on the basis of quantitative measurements of high density lipoproteins and their constitutive polypeptides. By a variety of quantitative immunological methods, such as one-dimensional Laurell eletrophoresis, two-dimensional immunoelectrophoresis, and double-antibody radioimmunoassay, the total amount of apoprotein A-I and apoprotein A-I contained in the serum of heterozygous patients and the distribution of these A apoproteins among serum lipoproteins have been determined. The molar ration of apoprotein A-I and apoprotein A-II contained in high density lipoproteins of heterozygous patients did not significantly differ from that of control preparations, although the total mass of high density lipoproteins was reduced by approximately 50%. The elution profile of high density lipoproteins from agarose columns and their morphological appearance, as ascertained by electron microscopy, were similar to control preparations. In addition to the quantitative alterations of serum lipoproteins, lipid storage in histiocytes of the rectal mucosa obtained from heterozygous patients has been documented. It is concluded that patients heterozygous for Tangier disease have normal high density lipoproteins in circulation, the total mass of which is reduced by approximately 50%. Images PMID:198431

  6. Enhanced adherence of mouse fibroblast and vascular cells to plasma modified polyethylene.

    PubMed

    Reznickova, Alena; Novotna, Zdenka; Kolska, Zdenka; Kasalkova, Nikola Slepickova; Rimpelova, Silvie; Svorcik, Vaclav

    2015-01-01

    Since the last decade, tissue engineering has shown a sensational promise in providing more viable alternatives to surgical procedures for harvested tissues, implants and prostheses. Biomedical polymers, such as low-density polyethylene (LDPE), high-density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE), were activated by Ar plasma discharge. Degradation of polymer chains was examined by determination of the thickness of ablated layer. The amount of an ablated polymer layer was measured by gravimetry. Contact angle, measured by goniometry, was studied as a function of plasma exposure and post-exposure aging times. Chemical structure of modified polymers was characterized by angle resolved X-ray photoelectron spectroscopy. Surface chemistry and polarity of the samples were investigated by electrokinetic analysis. Changes in surface morphology were followed using atomic force microscopy. Cytocompatibility of plasma activated polyethylene foils was studied using two distinct model cell lines; VSMCs (vascular smooth muscle cells) as a model for vascular graft testing and connective tissue cells L929 (mouse fibroblasts) approved for standardized material cytotoxicity testing. Specifically, the cell number, morphology, and metabolic activity of the adhered and proliferated cells on the polyethylene matrices were studied in vitro. It was found that the plasma treatment caused ablation of the polymers, resulting in dramatic changes in their surface morphology and roughness. ARXPS and electrokinetic measurements revealed oxidation of the polymer surface. It was found that plasma activation has a positive effect on the adhesion and proliferation of VSMCs and L929 cells. PMID:25953566

  7. Immobilization of bacteria in microgel grafted onto macroporous polyethylene

    NASA Astrophysics Data System (ADS)

    Trelles, J. A.; Quiroga, F.; Britos, C.; Smolko, Eduardo E.; Grasselli, Mariano

    2010-03-01

    The development of " Green Chemistry" requires new materials to replace the conventional organic chemistry by biological catalysts, to produce fine chemicals in an environmentally friendly manner. Microbial whole cells can be directly used as biocatalysts, providing a simple and cheap methodology since enzyme isolation and purification are avoided. High-density polyethylene (HDPE) is a very stable polymer though it can be activated by gamma radiation to induce grafting. Glycidyl methacrylate was grafted onto macroporous HDPE and PP in the range of 1-6%, proportional to the initial monomer concentration. Grafted polymers were further chemically modified with ethylenediamine to generate a cationic hydrogel of micron-size thickness onto the internal polymer surfaces. Modified polymers were able to immobilize Gram-positive and Gram-negative bacteria that can catalyze a chemical reaction as efficient as free cells do.

  8. Oxidation-Enhanced TSC and TSSP of Polyethylene

    NASA Astrophysics Data System (ADS)

    Mizutani, Teruyoshi; Ikeda, Seita; Ieda, Masayuki

    1986-01-01

    The conduction, TSC and TSSP of both low-density and high-density polyethylene (LDPE and HDPE) were found to be strongly enhanced by oxidation. Oxidized PE showed two TSC peaks, P1 and P2. Peak P1 was caused by the depolarization of C{=}0 dipoles and peak P2 originated from injected homo space charge. Thermal pulse experiments revealed the existence of negative and positive homo space charges in oxidized PE polarized at high fields. VTSSP(T) increased in the temperature regions of peaks P1 and P2, and TSSP and TSC were found to be closely related to each other. Peak P1 and VTSSP(T) at room temperature were proportional to the concentration of C{=}0 groups and can be utilized for diagnosing the degradation of PE accompanied by oxidation.

  9. Textural changes in metallurgical coke prepared with polyethylene

    NASA Astrophysics Data System (ADS)

    Gornostayev, Stanislav S.; Heino, Jyrki J.; Kokkonen, Tommi M. T.; Makkonen, Hannu T.; Huttunen, Satu M. M.; Fabritius, Timo M. J.

    2014-10-01

    The effect of high-density polyethylene (HDPE) on the textural features of experimental coke was investigated using polarized-light optical microscopy and wavelet-based image analysis. Metallurgical coke samples were prepared in a laboratory-scale furnace with 2.5%, 5.0%, 7.5%, 10.0%, and 12.5% HDPE by mass, and one sample was prepared by 100% coal. The amounts and distribution of textures (isotropic, mosaic and banded) and pores were obtained. The calculations reveal that the addition of HDPE results in a decrease of mosaic texture and an increase of isotropic texture. Ethylene formed from the decomposition of HDPE is considered as a probable reason for the texture modifications. The approach used in this study can be applied to indirect evaluation for the reactivity and strength of coke.

  10. 21 CFR 177.1615 - Polyethylene, fluorinated.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyethylene, fluorinated. 177.1615 Section 177... Components of Single and Repeated Use Food Contact Surfaces § 177.1615 Polyethylene, fluorinated. Fluorinated polyethylene, identified in paragraph (a) of this section, may be safely used as food-contact articles...

  11. 21 CFR 177.1615 - Polyethylene, fluorinated.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Polyethylene, fluorinated. 177.1615 Section 177... Components of Single and Repeated Use Food Contact Surfaces § 177.1615 Polyethylene, fluorinated. Fluorinated polyethylene, identified in paragraph (a) of this section, may be safely used as food-contact articles...

  12. 21 CFR 177.1615 - Polyethylene, fluorinated.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polyethylene, fluorinated. 177.1615 Section 177... Components of Single and Repeated Use Food Contact Surfaces § 177.1615 Polyethylene, fluorinated. Fluorinated polyethylene, identified in paragraph (a) of this section, may be safely used as food-contact articles...

  13. 21 CFR 177.1620 - Polyethylene, oxidized.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polyethylene, oxidized. 177.1620 Section 177.1620... Components of Single and Repeated Use Food Contact Surfaces § 177.1620 Polyethylene, oxidized. Oxidized polyethylene identified in paragraph (a) of this section may be safely used as a component of...

  14. 21 CFR 573.780 - Polyethylene.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Polyethylene. 573.780 Section 573.780 Food and... Listing § 573.780 Polyethylene. (a) Identity. Polyethylene consists of basic polymers manufactured by the catalytic polymerization of ethylene. (b) Specifications. (1) For the purposes of this section,...

  15. 21 CFR 177.1615 - Polyethylene, fluorinated.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polyethylene, fluorinated. 177.1615 Section 177... Components of Single and Repeated Use Food Contact Surfaces § 177.1615 Polyethylene, fluorinated. Fluorinated polyethylene, identified in paragraph (a) of this section, may be safely used as food-contact articles...

  16. 21 CFR 177.1620 - Polyethylene, oxidized.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polyethylene, oxidized. 177.1620 Section 177.1620... Components of Single and Repeated Use Food Contact Surfaces § 177.1620 Polyethylene, oxidized. Oxidized polyethylene identified in paragraph (a) of this section may be safely used as a component of...

  17. 21 CFR 573.780 - Polyethylene.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Polyethylene. 573.780 Section 573.780 Food and... Listing § 573.780 Polyethylene. (a) Identity. Polyethylene consists of basic polymers manufactured by the catalytic polymerization of ethylene. (b) Specifications. (1) For the purposes of this section,...

  18. The final stage of gravitational collapse for high density fluid medium

    SciTech Connect

    Souza, R. G.; De Campos, M.

    2013-03-25

    The High density high density fluids can be represented by a stiff matter state equation P={rho} and also by the Hagedorn state equation. The first is constructed using a lagrangian that allows bare nucleons to interact attractively via scalar meson exchange, and repulsively by a more massive vector meson exchange; the second consider that for large mass the spectrum of hadrons grows exponentially, namely {rho}(m) {approx}exp(m/T{sub H}), where T{sub H} is the Hagedorn temperature, resulting the state equation P = P{sub 0}+{rho}{sub 0}ln({rho}/{rho}{sub 0}). We study the gravitational collapse for a high density fluid, considering a Hagedorn state equation in a presence of a vacuum component.

  19. Antimony mediated growth of high-density InAs quantum dots for photovoltaic cells

    SciTech Connect

    Tutu, F. K.; Wu, J.; Lam, P.; Tang, M.; Liu, H.; Miyashita, N.; Okada, Y.; Wilson, J.; Allison, R.

    2013-07-22

    We report enhanced solar cell performance using high-density InAs quantum dots. The high-density quantum dot was grown by antimony mediated molecular beam epitaxy. In-plane quantum dot density over 1 × 10{sup 11} cm{sup −2} was achieved by applying a few monolayers of antimony on the GaAs surface prior to quantum dot growth. The formation of defective large clusters was reduced by optimization of the growth temperature and InAs coverage. Comparing with a standard quantum dot solar cell without the incorporation of antimony, the high-density quantum dot solar cell demonstrates a distinct improvement in short-circuit current from 7.4 mA/cm{sup 2} to 8.3 mA/cm{sup 2}.

  20. FALCON: fast and unbiased reconstruction of high-density super-resolution microscopy data

    PubMed Central

    Min, Junhong; Vonesch, Cédric; Kirshner, Hagai; Carlini, Lina; Olivier, Nicolas; Holden, Seamus; Manley, Suliana; Ye, Jong Chul; Unser, Michael

    2014-01-01

    Super resolution microscopy such as STORM and (F)PALM is now a well known method for biological studies at the nanometer scale. However, conventional imaging schemes based on sparse activation of photo-switchable fluorescent probes have inherently slow temporal resolution which is a serious limitation when investigating live-cell dynamics. Here, we present an algorithm for high-density super-resolution microscopy which combines a sparsity-promoting formulation with a Taylor series approximation of the PSF. Our algorithm is designed to provide unbiased localization on continuous space and high recall rates for high-density imaging, and to have orders-of-magnitude shorter run times compared to previous high-density algorithms. We validated our algorithm on both simulated and experimental data, and demonstrated live-cell imaging with temporal resolution of 2.5 seconds by recovering fast ER dynamics. PMID:24694686

  1. High-density metallic nanogaps fabricated on solid substrates used for surface enhanced Raman scattering.

    PubMed

    Lu, Gang; Li, Hai; Wu, Shixin; Chen, Peng; Zhang, Hua

    2012-02-01

    The Raman signal of adsorbed molecules can be significantly enhanced by utilizing metallic structures with high-density Raman hot spots used as surface enhanced Raman scattering (SERS) substrates. In this work, we develop a simple, convenient and tunable method to fabricate high-density Ag or Au nanogaps on Si wafers. These nanogaps can serve as Raman hot spots, leading to dramatic enhancement of the Raman signal. The high-density nanogaps can be formed by repeating the electroless deposition of Ag NPs (or Au NPs) and coating of p-aminothiophenol (PATP, a Raman probe) on the deposited Ag NPs (or Au NPs) through the self-assembly process. After removal of PATP by O(2) plasma, the as-fabricated SERS substrate can be reused for the detection of other molecules. PMID:22159183

  2. A high density recombination map of the pig reveals a correlation between sex-specific recombination and GC content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The availability of a high-density SNP chip and a reference genome sequence of the pig have enabled the construction of a high-density linkage map. A high density linkage map is an essential tool for the further fine-mapping of QTL for a variety of traits in the pig and for a better und...

  3. Getting a prescription filled

    MedlinePlus

    ... health plan: Call the phone number on the back of your insurance card. Call the pharmacy you want to use to see if they have a contract with your insurance plan. To help the pharmacist fill the prescription: Make sure all of the information ...

  4. Development of a high-density energy-storage capacitor for Nova

    SciTech Connect

    Haskell, D.K.; Cooper, R.A.; Sevigny, J.A.; Merritt, B.T.; Carder, B.M.; Whitham, K.

    1981-10-22

    This paper covers Maxwell's approach to developing energy storage capacitors. Based on previous capacitor designs of 3 KJ, 5 KJ and 10 KJ, the final Nova 12.5 KJ capacitor evolved. At the outset of the Nova capacitor development program, a relatively new dielectric system, polypropylene-paper-DOP, seemed to show superiority in volumetric efficiency, life, and more importantly cost. However, as a result of studies performed at Maxwell, a high-density, energy-storage capacitor was developed utilizing new high-quality, high-density paper and caster oil as the dielectric. Test data have demonstrated that the Maxwell 12.5 KJ capacitor exceeds all LLNL's qualification requirements.

  5. Device and method for electron beam heating of a high density plasma

    DOEpatents

    Thode, L.E.

    A device and method for relativistic electron beam heating of a high density plasma in a small localized region are described. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10/sup 17/ to 10/sup 20/.

  6. Advanced organic dye for high-speed, high-density optical media

    NASA Astrophysics Data System (ADS)

    Kodaira, Takuo; Matsuda, Isao; Somei, Hidenori; Tsuzuki, Takeo; Yokoyama, Daizo; Endo, Akihisa; Takeguchi, Kazunobu; Kojo, Shinichi; Miyazawa, Fuyuki; Otsu, Takeshi; Murai, Wakaaki; Hattori, Masashi; Shimomai, Kenichi; Oshita, Junji; Asano, Sho; Shimizu, Atsuo; Fujii, Toru

    2015-09-01

    Advances in organic dye progress are indispensable for high-speed, high-density recording of recordable Blu-ray Disc™ (BD-R) low-to-high (LTH) discs without a low elastic modulus layer. The optimal physical properties of the organic dyes, i.e., a low decomposition calorific value, a low decomposition temperature, and a large n-value, were determined, and a dye with these properties was synthesized. A BD-R disc using the dye conformed to the BD-R LTH standard at 8× recording and ever higher speeds should be possible. Furthermore, the possibility of 33 GB/layer high-density recording was suggested.

  7. Multiaxial deformation of polyethylene and polyethylene/clay nanocomposites: In situ synchrotron small angle and wide angle X-ray scattering study

    SciTech Connect

    Gurun, Bilge; Bucknall, David G.; Thio, Yonathan S.; Teoh, Chin Ching; Harkin-Jones, Eileen

    2013-01-10

    A unique in situ multiaxial deformation device has been designed and built specifically for simultaneous synchrotron small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) measurements. SAXS and WAXS patterns of high-density polyethylene (HDPE) and HDPE/clay nanocomposites were measured in real time during in situ multiaxial deformation at room temperature and at 55 C. It was observed that the morphological evolution of polyethylene is affected by the existence of clay platelets as well as the deformation temperature and strain rate. Martensitic transformation of orthorhombic into monoclinic crystal phases was observed under strain in HDPE, which is delayed and hindered in the presence of clay nanoplatelets. From the SAXS measurements, it was observed that the thickness of the interlamellar amorphous region increased with increasing strain, which is due to elongation of the amorphous chains. The increase in amorphous layer thickness is slightly higher for the nanocomposites compared to the neat polymer.

  8. Closing the gaps on human chromosome 19 revealed genes with a high density of repetitive tandemly arrayed elements.

    SciTech Connect

    Leem, Sun-Hee; Kouprina, Natalay; Grimwood, Jane; Kim, Jung-Hyun; Mullokandov, Michael; Yoon, Young-Ho; Chae, Ji-Youn; Morgan, Jenna; Lucas, Susan; Richardson, Paul; Detter, Chris; Glavina, Tijana; Rubin, Eddy; Barrett, J. Carl; Larionov, Vladimir

    2003-09-01

    The reported human genome sequence includes about 400 gaps of unknown sequence that were not found in the bacterial artificial chromosome (BAC) and cosmid libraries used for sequencing of the genome. These missing sequences correspond to {approx} 1 percent of euchromatic regions of the human genome. Gap filling is a laborious process because it relies on analysis of random clones of numerous genomic BAC or cosmid libraries. In this work we demonstrate that closing the gaps can be accelerated by a selective recombinational capture of missing chromosomal segments in yeast. The use of both methodologies allowed us to close the four remaining gaps on the human chromosome 19. Analysis of the gap sequences revealed that they contain several abnormalities that could result in instability of the sequences in microbe hosts, including large blocks of micro- and minisatellites and a high density of Alu repeats. Sequencing of the gap regions, in both BAC and YAC forms, allowed us to generate a complete sequence of four genes, including the neuronal cell signaling gene SCK1/SLI. The SCK1/SLI gene contains a record number of minisatellites, most of which are polymorphic and transmitted through meiosis following a Mendelian inheritance. In conclusion, the use of the alternative recombinational cloning system in yeast may greatly accelerate work on closing the remaining gaps in the human genome (as well as in other complex genomes) to achieve the goal of annotation of all human genes.

  9. High-density aerogels with ultralow sound velocity: Microstructure is a key parameter determining the sound velocity

    NASA Astrophysics Data System (ADS)

    Du, Ai; Zhou, Bin; Shen, Yang; Yu, Qiujie; Shen, Jun

    2014-03-01

    Aerogels are more and more regarded as a new state of matter nowadays because of its diverse chemical compositions and unique properties which could fill the gap between condensed matter and gas-state matter. Among the properties, the ultralow sound velocity in the aerogels (lower than that in the air) is of great interests. J. Fricke's group studied many kinds of aerogels with different compositions and found that the sound velocity was mainly influenced by the density. Thus they obtained the lowest sound velocity result (~ 100 m/s) in a low-density silica aerogel medium (~ 0.05 g.cm-3) . Here we studied the acoustical properties of the aerogels with the similar high density (about 1.3 g.cm-3) but different skeleton structure (nano-, micro- or nano-/micro- structured) by adjusting the phase separation mode. The sound velocities of all the aerogels are below 300 m.s-1, among which micro-/nano- structured aerogel exhibits lowest longitudinal wave velocity (below 80 m.s-1) . Further structural studies indicated that the hierarchical arrangement of microstructure is the key parameter determining the sound velocity besides the density. This work was supported by the National Natural Science Foundation of China (51102184, 51172163), National High-tech R&D Program of China (863 Program, 2013AA031801) and National Science and Technology Support Program (2013BAJ01B01).

  10. Probing polyethylene crystallization via simultaneous Raman scattering, rheology and microscopy

    NASA Astrophysics Data System (ADS)

    Migler, Kalman; Kotula, Anthony; Hight Walker, Angela

    The structure and rheology of polyolefins during crystallization is of critical importance to the polymer processing industry. Here we present simultaneous Raman scattering, rheological and optical microscopy measurements of crystallizing high density polyethylenes during quiescent and slow flow conditions. Raman scattering measurements during quiescent crystallization allow us to quantify three different mass fractions of chain conformers: an amorphous fraction, an orthorhombic crystalline fraction, and a fraction of chains that contain many consecutive trans bonds but are not part of the orthorhombic crystal. These non-crystalline consecutive trans (NCCT) conformers are generated as a precursor to crystallinity. Slow steady shear rates (1 s 1) applied during isothermal crystallization experiments dramatically increase the crystallization rate as well as the amount of NCCT conformers produced. Optical measurements of sheared samples during crystallization reveal the formation of fiber structures that compositionally contain more NCCT conformers than the surrounding melt. The increase in the complex shear modulus commonly measured for crystallizing polyethylenes correlates with the growth of chain conformers and the appearance of spherulites within the melt.

  11. The Pain in Storage: Work Safety in a High-Density Shelving Facility

    ERIC Educational Resources Information Center

    Atkins, Stephanie A.

    2005-01-01

    An increasing number of academic and research libraries have built high-density shelving facilities to address overcrowding conditions in their regular stacks. However, the work performed in these facilities is physically strenuous and highly repetitive in nature and may require the use of potentially dangerous equipment. This article will examine…

  12. Device and method for electron beam heating of a high density plasma

    DOEpatents

    Thode, Lester E.

    1981-01-01

    A device and method for relativistic electron beam heating of a high density plasma in a small localized region. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target plasma is ionized prior to application of the electron beam by means of a laser or other preionization source. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region within the high density plasma target.

  13. Radiation Tests of Highly Scaled, High-Density, Commercial, Nonvolatile NAND Flash Memories - Update 2010

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Nguyen, Duc N.

    2010-01-01

    High-density, commercial, nonvolatile flash memories with NAND architecture are now available from several manufacturers. This report examines SEE effects and TID response in single-level cell (SLC) and multi-level cell (MLC) NAND flash memories manufactured by Micron Technology.

  14. Radiation Tests of Highly scaled, High-Density, Commercial, Nonvolatile NAND Flash Memories--Update 2011

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Nguyen, Duc N.

    2011-01-01

    High-density, commercial, nonvolatile flash memories with NAND architecture are now available from several manufacturers. This report examines SEE effects and TID response in single-level cell (SLC) 32Gb and multi-level cell (MLC) 64Gb NAND flash memories manufactured by Micron Technology.

  15. CHARACTERIZATION AND PHYSICAL MAPPING OF MAIZE BAC LIBRARIES USING HIGH DENSITY BAC FILTER HYBRIDIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A HindIII and an EcoRI maize BAC library have been constructed from maize inbred line B73. Use of both libraries to make a physical map should minimize the under representation of certain genomic regions caused by the use of a particular restriction enzyme. High-density filter sets from the two libr...

  16. CHARACTERIZATION AND PHYSICAL MAPPING OF MAIZE BAC LIBRARIES USING HIGH DENSITY BAC FILTER HYBRIDIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-density filter sets from two maize B73 libraries containing 6X (HindIII) and 7X (EcoRI) haploid genome equivalents, respectively, were evaluated with a set of complex probes. The complex probes will provide information on chromosome architecture and organellar DNA content. A second set of pro...

  17. High Density Brassica Oleracea Linkage Map: Identification of Useful New Linkages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We constructed a 1257-marker, high-density genetic map of Brassica oleracea spanning 703cM in nine linkage groups, named LG1-LG9. It was developed in a F2 segregating population of 143 individuals obtained by crossing two double-haploid plants of broccoli Early-Big and cauliflower An-Nan Early. The...

  18. Library Off-Site Shelving: Guide for High-Density Facilities.

    ERIC Educational Resources Information Center

    Nitecki, Danuta A., Ed.; Kendrick, Curtis L., Ed.

    This collection of essays addresses the planning, construction, and operating issues relating to high-density library shelving facilities. The volume covers essential topics that address issues relating to the building, its operations, and serving the collections. It begins with an introduction by the volume's editors, "The Paradox and Politics of…

  19. Strategies to build high-density linkage maps of the porcine 60k SNP chip

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We present here two different strategies to compute high-density linkage maps based on the porcine 60k SNP chip that was genotyped on 4 different pedigrees with a total of 5600 animals. The first strategy uses the draft sequence as a reference order, the SNP being first mapped to it. The second stra...

  20. 76 FR 58393 - High Density Traffic Airports; Notice of Determination Regarding Low Demand Periods at Ronald...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-21

    ..., which the FAA allocates for a specific 60-minute period, for each scheduled operation. \\1\\ 33 FR 17896... first come, first served allocation procedure is inappropriate. \\2\\ 50 FR 52195 (Dec. 20, 1985). FAA... Federal Aviation Administration 14 CFR Part 93 High Density Traffic Airports; Notice of...

  1. 77 FR 19076 - High Density Traffic Airports; Notice of Determination Regarding Low Demand Periods at Ronald...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-30

    ...\\ 33 FR 17896 (Dec. 3, 1968). In 1985, the FAA issued part 93 subpart S (the ``Buy/Sell Rule'').\\2\\ As... the 0600 hour is not a low demand period.\\3\\ \\2\\ 50 FR 52195 (Dec. 20, 1985). \\3\\ 76 FR 58393 (Sept... Federal Aviation Administration 14 CFR Part 93 High Density Traffic Airports; Notice of...

  2. Isotopic Anomalies Preserved Within Internal Grains in High-Density Presolar Graphites

    NASA Astrophysics Data System (ADS)

    Croat, T. K.; Bernatowicz, T. J.; Jadhav, M.

    2014-09-01

    NanoSIMS measurements of high-density (HD) Orgueil graphites are presented, concentrating on those contain carbide and rutile phases. We report a new internal SiC-C grain with 12C, 29Si and 30Si enrichments that likely originated in a massive star.

  3. Development and Characterization of a High Density SNP Genotyping Assay for Cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The success of genomewide association (GWA) studies for the detection of sequence variation affecting complex traits in human has spurred interest in the use of large-scale high-density single nucleotide polymorphism (SNP) genotyping for the identification of quantitative trait loci (QTL) and for ma...

  4. High density ash slurry pumping and disposal: An environmentally safe and economical alternative

    SciTech Connect

    Broek, B. van den

    1999-07-01

    The paper describes conventional ash disposal systems; high density slurry transportation and disposal systems, including the design, disposal site, technical features, sloped disposal site operating parameters, slurry quality and deposit management; typical operational questions; specific advantages of the proposed GEHO system; and GEHO piston diaphragm pumps.

  5. Comparing high density LIDAR and medium resolution GPS generated elevation data for predicting yield stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High density light detection and ranging (LIDAR) imaging has been shown to be able to define yield stability areas of a field for multi-cropping. Since LIDAR imaging is expensive and not widely available, we hypothesized that medium resolution GPS elevation data which is commonly collected with var...

  6. Improvement in mechanical and barrier properties of polyethylene blown films using atomic layer deposition

    SciTech Connect

    Lee, Gyeong Beom; Hak Song, Seung; Wook Moon, Sung; Woo Kim, Jun; Hyung Shim, Joon; Choi, Byoung-Ho; Moo Heo, Young

    2014-01-15

    Recently, thin films deposited on polymer substrates have been widely utilized as encapsulation barriers in electronic applications such as flexible displays, packaging films, and organic light-emitting diodes. The barrier and mechanical properties of these films are critical aspects when using them for protecting the inner modules of electronic devices from environmental factors such as moisture, oxygen, and sunlight. In particular, polymers can be degraded or decomposed more easily than other materials under such environmental conditions. Therefore, polymer films can be deposited using thin functional materials; however, suitable deposition methods for polymers are scarce owing to many limitations such as low melting/glass transition temperature, thermal degradation, and oxidation. In this study, a thin alumina oxide film was deposited on a high-density polyethylene blown film by using atomic layer deposition. The mechanical and barrier properties of the alumina oxide film deposited on the polyethylene film were characterized by a microtensile test and water vapor transmission rate test. Process conditions such as process temperature, plasma surface treatment, and number of cycles were varied to ascertain the reliability of the thin alumina oxide film deposited on the high-density polyethylene blown film. The results showed that the barrier property of the deposited film improved upon the application of plasma surface treatment, and that its mechanical properties varied under different process conditions.

  7. Gas filled panel insulation

    DOEpatents

    Griffith, B.T.; Arasteh, D.K.; Selkowitz, S.E.

    1993-12-14

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation. 18 figures.

  8. Gas filled panel insulation

    DOEpatents

    Griffith, Brent T.; Arasteh, Dariush K.; Selkowitz, Stephen E.

    1993-01-01

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation.

  9. Isolation and Characterization of an Abnormal High Density Lipoprotein in Tangier Disease

    PubMed Central

    Assmann, Gerd; Herbert, Peter N.; Fredrickson, Donald S.; Forte, Trudy

    1977-01-01

    The nature of the high density lipoproteins has been investigated in five patients homozygous for Tangier disease (familial high density lipoprotein deficiency). It has been established that Tangier high density lipoproteins, as isolated by ultracentrifugation, are morphologically heterogenous and contain several proteins (Apo B, albumin, and Apo A-II). An abnormal lipoprotein has been isolated from the d = 1.063-1.21 g/ml ultracentrifugal fraction by agarose-column chromatography which contains apoprotein A-II as the sole protein constituent. In negative-stain electron microscopy, these lipoproteins appeared as spherical particles 55-75 Å in diameter. By a variety of criteria (immunochemical, polyacrylamide electrophoresis, amino acid composition, and fluorescence measurements), apoprotein A-I the major apoprotein of normal high density lipoproteins and the C apoproteins were absent from this lipoprotein. As demonstrated by 125I very low density lipoprotein incubation experiments with Tangier plasma, C apoproteins did not associate with lipoproteins of d = 1.063-1.21 g/ml. Tangier apoprotein A-II, isolated to homogeneity by delipidation of the apoprotein A-II-containing lipoprotein or Sephadex G-200 guanidine-HCl chromatography of the d = 1.063-1.21 g/ml fraction, was indistinguishable from control apoprotein A-II with respect to amino acid composition and migration of tryptic peptides in urea-polyacrylamide electrophoresis. The ability of Tangier apoprotein A-II to bind phospholipid was demonstrated by in vitro reconstitution experiments and morphological and chemical analysis of lipid-protein complexes. It is concluded that normal high density lipoproteins, as defined by polypeptide composition and morphological appearance, are absent from Tangier plasma and that as a consequence, the impairment of C apoprotein metabolism contributes to the hypertriglyceridemia and fasting chylomicronemia observed in these patients. Images PMID:194920

  10. Properties of dried distillers grains with solubles, Paulownia wood, and pine wood reinforced high density polyethylene composites: Effect of maleation, chemical modification, and the mixing of fillers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a need to identify usable lignocellulosic materials that can be blended with thermoplastic resins to produced commercial lignocellulosic plastic composites (LPC) at lower costs with improved performance. The core objectives of this study are to: 1) evaluate the use of dried distillers grai...

  11. Safety and Biocompatibility of a New High-Density Polyethylene-Based Spherical Integrated Porous Orbital Implant: An Experimental Study in Rabbits

    PubMed Central

    Fernandez-Bueno, Ivan; Di Lauro, Salvatore; Alvarez, Ivan; Lopez, Jose Carlos; Garcia-Gutierrez, Maria Teresa; Fernandez, Itziar; Larra, Eva; Pastor, Jose Carlos

    2015-01-01

    Purpose. To evaluate clinically and histologically the safety and biocompatibility of a new HDPE-based spherical porous orbital implants in rabbits. Methods. MEDPOR (Porex Surgical, Inc., Fairburn, GA, USA), OCULFIT I, and OCULFIT II (AJL Ophthalmic S.A., Vitoria, Spain) implants were implanted in eviscerated rabbis. Animals were randomly divided into 6 groups (n = 4 each) according to the 3 implant materials tested and 2 follow-up times of 90 or 180 days. Signs of regional pain and presence of eyelid swelling, conjunctival hyperemia, and amount of exudate were semiquantitatively evaluated. After animals sacrifice, the implants and surrounding ocular tissues were processed for histological staining and polarized light evaluation. Statistical study was performed by ANOVA and Kaplan-Meier analysis. Results. No statistically significant differences in regional pain, eyelid swelling, or conjunctival hyperemia were shown between implants and/or time points evaluated. However, amount of exudate differed, with OCULFIT I causing the smallest amount. No remarkable clinical complications were observed. Histological findings were similar in all three types of implants and agree with minor inflammatory response. Conclusions. OCULFIT ophthalmic tolerance and biocompatibility in rabbits were comparable to the clinically used MEDPOR. Clinical studies are needed to determine if OCULFIT is superior to the orbital implants commercially available. PMID:26689343

  12. Sintering maps for ceramic-filled-glass composites

    SciTech Connect

    Ewsuk, K.G.

    1990-01-01

    Ceramic-filled-glass (CFG) composites densify by viscous flow during final-stage, non-reactive, liquid-phase sintering (NLPS). The rate of densification is controlled by the viscosity of the CFG composite dispersion during sintering, which is determined by the concentration of ceramic filler in the composite, and the viscosity of the suspending glass medium. A mathematical expression has been developed that determines the critical filler concentration in a given viscosity glass at which high-density CFG composites will be produced in a given time during final-stage NLPS. This expression has been used to predict the effects of sintering time, pore size, and glass viscosity on critical filler concentration, and to construct final-stage sintering maps that provide guidelines for designing and processing high-density CFG composites. 12 refs., 2 figs.

  13. Dye filled security seal

    DOEpatents

    Wilson, Dennis C. W.

    1982-04-27

    A security seal for providing an indication of unauthorized access to a sealed object includes an elongate member to be entwined in the object such that access is denied unless the member is removed. The elongate member has a hollow, pressurizable chamber extending throughout its length that is filled with a permanent dye under greater than atmospheric pressure. Attempts to cut the member and weld it together are revealed when dye flows through a rupture in the chamber wall and stains the outside surface of the member.

  14. Development of ultra-high-density screening tools for microbial "omics".

    PubMed

    Bean, Gordon J; Jaeger, Philipp A; Bahr, Sondra; Ideker, Trey

    2014-01-01

    High-throughput genetic screens in model microbial organisms are a primary means of interrogating biological systems. In numerous cases, such screens have identified the genes that underlie a particular phenotype or a set of gene-gene, gene-environment or protein-protein interactions, which are then used to construct highly informative network maps for biological research. However, the potential test space of genes, proteins, or interactions is typically much larger than current screening systems can address. To push the limits of screening technology, we developed an ultra-high-density, 6144-colony arraying system and analysis toolbox. Using budding yeast as a benchmark, we find that these tools boost genetic screening throughput 4-fold and yield significant cost and time reductions at quality levels equal to or better than current methods. Thus, the new ultra-high-density screening tools enable researchers to significantly increase the size and scope of their genetic screens. PMID:24465499

  15. Subfractions of high-density lipoprotein (HDL) and dysfunctional HDL in chronic kidney disease patients

    PubMed Central

    Banach, Maciej

    2016-01-01

    A number of studies have shown that chronic kidney disease (CKD) is associated with increased risk for cardiovascular disease (CVD). Chronic kidney disease is characterized by significant disturbances in lipoprotein metabolism, including differences in quantitative and qualitative content of high-density lipoprotein (HDL) particles. Recent studies have revealed that serum HDL cholesterol levels do not predict CVD in CKD patients; thus CKD-induced modifications in high-density lipoprotein (HDL) may be responsible for the increase in CV risk in CKD patients. Various methods are available to separate several subclasses of HDL and confirm their atheroprotective properties. However, under pathological conditions associated with inflammation and oxidation, HDL can progressively lose normal biological activities and be converted into dysfunctional HDL. In this review, we highlight the current state of knowledge on subfractions of HDL and HDL dysfunction in CKD. PMID:27478466

  16. High-Density and Uniform Lead Halide Perovskite Nanolaser Array on Silicon.

    PubMed

    Wang, Kaiyang; Gu, Zhiyuan; Liu, Shuai; Sun, Wenzhao; Zhang, Nan; Xiao, Shumin; Song, Qinghai

    2016-07-01

    The realization of high density and highly uniform nanolaser arrays in lead halide perovskite is quite challenging, especially on silicon. Herein, we demonstrate a simple way to form lead halide nanolaser array on silicon chip with high density and uniform lasing wavelengths. By positioning a perovskite microwire onto a silicon grating, only the suspended parts can hold high quality (Q) resonances and generate laser emissions. As the perovskite microwire is periodically segmented by the silicon grating, the transverse lasers are divided into a periodic nanolaser array and the lasing wavelengths from different subunits are almost the same. The transverse laser has been observed in an air gap as narrow as 420 nm, increasing the density of nanolasers to about 1250 per millimeter (800 nm period in experiment). We believe this research shall shed light on the development of perovskite microlaser and nanolaser arrays on silicon and their applications. PMID:27320490

  17. A guide to the porcine anatomy for the interventional electrophysiologist. Fluoroscopy and high density electroanatomical mapping.

    PubMed

    Hilbert, Sebastian; Kosiuk, Jedrzej; John, Silke; Hindricks, Gerhard; Bollmann, Andreas

    2015-02-01

    Invasive electrophysiology is a rapidly developing field of cardiovascular science with a constant need for inventions and testing of new technologies and concepts. Despite the swine model being an established tool in biomedical research no comprehensive guide for interventional electrophysiologists exists. The aim of the current article is to provide a practical overview of the pig anatomy, fluoroscopic views, and corresponding high density electroanatomic maps using a novel mapping system and a practical guide for interventions and techniques. In 17 pigs, fluoroscopic images of the right atrium, coronary sinus (CS), left atrium, and pulmonary veins as well as the right and left ventricles were obtained and correlated with ultra-high density electroanatomic maps and gross anatomy. Pitfalls of the porcine anatomy are precisely addressed, and alternative access techniques to overcome those issues are suggested. Important differences to human electrophysiological studies are highlighted. Complementary models such as cardiac ischemia induction or renal and pulmonary artery denervation are discussed in detail. PMID:25630688

  18. Effect of Coulomb scattering on low-pressure high-density electronegative discharges.

    PubMed

    Kawamura, E; Birdsall, C K

    2005-02-01

    For electronegative plasmas with low gas pressure and high ion densities, we expect Coulomb collisions between positive and negative ions to dominate over collisions between ions and neutrals. We incorporated Nanbu's cumulative small-angle collision method [K. Nanbu, Phys. Rev. E, 55, 4642 (1997)] into our one-dimensional three-velocity-component particle-in-cell code PDP1 in order to study the effect of Coulomb collisions on low pressure high density electronegative discharges. Nanbu's method treats a succession of small-angle binary collisions as a single binary collision with a large scattering angle, which is far faster than treating each individual small-angle collision. We find that Coulomb collisions between positive and negative ions in low-pressure high-density electronegative discharges significantly modify the negative ion flux, density, and kinetic energy profiles. PMID:15783425

  19. Effect of Coulomb scattering on low-pressure high-density electronegative discharges

    SciTech Connect

    Kawamura, E.; Birdsall, C.K.

    2005-02-01

    For electronegative plasmas with low gas pressure and high ion densities, we expect Coulomb collisions between positive and negative ions to dominate over collisions between ions and neutrals. We incorporated Nanbu's cumulative small-angle collision method [K. Nanbu, Phys. Rev. E, 55, 4642 (1997)] into our one-dimensional three-velocity-component particle-in-cell code PDP1 in order to study the effect of Coulomb collisions on low pressure high density electronegative discharges. Nanbu's method treats a succession of small-angle binary collisions as a single binary collision with a large scattering angle, which is far faster than treating each individual small-angle collision. We find that Coulomb collisions between positive and negative ions in low-pressure high-density electronegative discharges significantly modify the negative ion flux, density, and kinetic energy profiles.

  20. Design and performance of ultra-high-density optical fiber cable with rollable optical fiber ribbons

    NASA Astrophysics Data System (ADS)

    Hogari, Kazuo; Yamada, Yusuke; Toge, Kunihiro

    2010-08-01

    This paper proposes a novel ultra-high-density optical fiber cable that employs rollable optical fiber ribbons. The cable has great advantages in terms of cable weight and diameter, and fiber splicing workability. Moreover, it will be easy to install in a small space in underground ducts and on residential and business premises. The structural design of the rollable optical fiber ribbon is evaluated theoretically and experimentally, and an optimum adhesion pitch P in the longitudinal direction is obtained. In addition, we examined the performance of ultra-high-density cables with a small diameter that employ rollable optical fiber ribbons and bending-loss insensitive optical fibers. The transmission, mechanical and mid-span access performance of these cables was confirmed to be excellent.

  1. Subfractions of high-density lipoprotein (HDL) and dysfunctional HDL in chronic kidney disease patients.

    PubMed

    Rysz-Górzyńska, Magdalena; Banach, Maciej

    2016-08-01

    A number of studies have shown that chronic kidney disease (CKD) is associated with increased risk for cardiovascular disease (CVD). Chronic kidney disease is characterized by significant disturbances in lipoprotein metabolism, including differences in quantitative and qualitative content of high-density lipoprotein (HDL) particles. Recent studies have revealed that serum HDL cholesterol levels do not predict CVD in CKD patients; thus CKD-induced modifications in high-density lipoprotein (HDL) may be responsible for the increase in CV risk in CKD patients. Various methods are available to separate several subclasses of HDL and confirm their atheroprotective properties. However, under pathological conditions associated with inflammation and oxidation, HDL can progressively lose normal biological activities and be converted into dysfunctional HDL. In this review, we highlight the current state of knowledge on subfractions of HDL and HDL dysfunction in CKD. PMID:27478466

  2. Low-pressure, high-density, and supersonic plasma flow generated by a helicon magnetoplasmadynamic thruster

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazunori; Komuro, Atsushi; Ando, Akira

    2014-11-01

    A high density magnetoplasmadynamic (MPD) plasma under a magnetic nozzle is produced with a low gas flow rate of argon by combining helicon and MPD plasma sources, where a cathode and an anode are located upstream and downstream of the helicon source, respectively. Once the high density helicon plasma is produced in the source tube, a pulsed current of a few kA is triggered between the cathode and anode. A plasma density above 1020 m-3 and a supersonic plasma flow (Mach number of ˜1.8) are obtained at ˜10 cm downstream of the source exit. As the thrust efficiency estimated from the measured plasma parameters is much higher than that of the simple MPD thruster, the helicon MPD thruster being proposed and tested potentially provides more efficient high-power plasma thruster.

  3. Dynamics of pulsed laser ablation in high-density carbon dioxide including supercritical fluid state

    NASA Astrophysics Data System (ADS)

    Urabe, Keiichiro; Kato, Toru; Stauss, Sven; Himeno, Shohei; Kato, Satoshi; Muneoka, Hitoshi; Baba, Motoyoshi; Suemoto, Tohru; Terashima, Kazuo

    2013-10-01

    To gain a better understanding of pulsed laser ablation (PLA) processes in high-density fluids, including gases, liquids, and supercritical fluids (SCFs), we have investigated the PLA dynamics in high-density carbon dioxide (CO2) using a time-resolved shadowgraph (SG) observation method. The SG images revealed that the PLA dynamics can be categorized into two domains that are separated by the gas-liquid coexistence curve and the Widom line, which forms a border between the gaslike and liquidlike domains of an SCF. Furthermore, a cavitation bubble observed in liquid CO2 near the critical point exhibited a particular characteristic: the formation of an inner bubble and an outer shell structure. The results indicate that the thermophysical properties of the reaction field generated by PLA can be dynamically tuned by controlling the solvent temperature and pressure, particularly near the critical point.

  4. A review on nanowires as an alternative high density magnetic storage media

    NASA Astrophysics Data System (ADS)

    Irshad, M. I.; Ahmad, F.; Mohamed, N. M.

    2012-09-01

    The thirst to design high density magnetic storage media with improved efficiency has always been one of the basic challenges in computer industry. In this paper, present challenges of magnetic storage media and different parameters that can affect the properties of magnetic nanowires have been investigated in detail. The magnetic nanowires are the promising candidate for the future high density magnetic storage media. So far the grain isolation is a problem while using thin film magnetic storage media. Further, during miniaturization, superparamagnetic limit is reached due to increasing thermal effects at this scale which makes the magnetic grains of magnetic nanowires susceptible to thermal fluctuations. To overcome this problem of superparamagnetism and grain isolation, nanowires with high coercivity, remanent magnetization and thermal stability are thought to be the alternatives. Alloy and multilayered magnetic nanowires prepared by some less expensive technique with suitable magnetic and thermal properties can serve to overcome this challenge.

  5. Efficient production of propionic acid through high density culture with recycling cells of Propionibacterium acidipropionici.

    PubMed

    Liu, Zhen; Ge, Yongsheng; Xu, Jing; Gao, Chao; Ma, Cuiqing; Xu, Ping

    2016-09-01

    The aim of this study was to explore propionic acid production via high density culture of Propionibacterium acidipropionici and recycling of cells. Results showed that final cells of P. acidipropionici from high density culture still had high metabolic activity for reuse. Using our process, 75.9gl(-1) propionic acid was produced, which was 1.84-fold of that in fed-batch fermentation with low cell density (41.2gl(-1)); the corresponding productivity was 100.0% higher than that in fed-batch fermentation with low cell density (0.16gl(-1)h(-1)). This bioprocess may have potential for the industrial production of propionic acid. PMID:27318164

  6. Advantages and Challenges of 10-Gbps Transmission on High-Density Interconnect Boards

    NASA Astrophysics Data System (ADS)

    Yee, Chang Fei; Jambek, Asral Bahari; Al-Hadi, Azremi Abdullah

    2016-06-01

    This paper provides a brief introduction to high-density interconnect (HDI) technology and its implementation on printed circuit boards (PCBs). The advantages and challenges of implementing 10-Gbps signal transmission on high-density interconnect boards are discussed in detail. The advantages (e.g., smaller via dimension and via stub removal) and challenges (e.g., crosstalk due to smaller interpair separation) of HDI are studied by analyzing the S-parameter, time-domain reflectometry (TDR), and transmission-line eye diagrams obtained by three-dimensional electromagnetic modeling (3DEM) and two-dimensional electromagnetic modeling (2DEM) using Mentor Graphics HyperLynx and Keysight Advanced Design System (ADS) electronic computer-aided design (ECAD) software. HDI outperforms conventional PCB technology in terms of signal integrity, but proper routing topology should be applied to overcome the challenge posed by crosstalk due to the tight spacing between traces.

  7. Ultra-sensitive high-density Rb-87 radio-frequency magnetometer

    SciTech Connect

    Savukov, I.; Boshier, M. G.; Karaulanov, T.

    2014-01-13

    Radio-frequency (RF) atomic magnetometers (AMs) can be used in many applications, such as magnetic resonance imaging and nuclear quadrupole resonance. High-density AMs provide both superior sensitivity and large bandwidth. Previously, high-density potassium AMs were demonstrated, but these magnetometers have various disadvantages, such as high-temperature of operation and bulky design. We demonstrate a rubidium-87 RF AM with 5 fT/Hz{sup 1/2} sensitivity (3 fT Hz{sup 1/2} probe noise), which is comparable to that of the best potassium magnetometers. Our magnetometer also features a simple fiber-optic design, providing maximum flexibility for magnetic-field measurements.

  8. High-Density 2D Homo- and Hetero- Plasmonic Dimers with Universal Sub-10-nm Gaps.

    PubMed

    Zhang, Mingliang; Large, Nicolas; Koh, Ai Leen; Cao, Yang; Manjavacas, Alejandro; Sinclair, Robert; Nordlander, Peter; Wang, Shan X

    2015-09-22

    Fabrication of high-density plasmonic dimers on a large (wafer) scale is crucial for applications in surface-enhanced spectroscopy, bio- and molecular sensing, and optoelectronics. Here, we present an experimental approach based on nanoimprint lithography and shadow evaporation that allows for the fabrication of high-density, large-scale homo- (Au-Au and Ag-Ag) and hetero- (Au-Ag) dimer substrates with precise and consistent sub-10-nm gaps. We performed scanning electron, scanning transmission electron, and atomic force microscopy studies along with a complete electron energy-loss spectroscopy (EELS) characterization. We observed distinct plasmonic modes on these dimers, which are well interpreted by finite-difference time-domain (FDTD) and plasmon hybridization calculations. PMID:26202803

  9. Long lifetime, high density single-crystal erbium compound nanowires as a high optical gain material

    NASA Astrophysics Data System (ADS)

    Yin, Leijun; Ning, Hao; Turkdogan, Sunay; Liu, Zhicheng; Nichols, Patricia L.; Ning, C. Z.

    2012-06-01

    Erbium-containing materials of long lifetime and high Er density are important for achieving strong luminescence and high optical gain in compact integrated photonics devices. We have systematically studied the lifetime and crystal quality as a function of growth conditions for an erbium compound that we recently reported, erbium chloride silicate (ECS). The lifetime for the best quality ECS nanowires can be as long as 540 μs, the longest for high-density Er-materials, representing a lifetime-density product as high as 8.7 × 1018 s cm-3. Such high density, long lifetime erbium materials can find many interesting applications such as compact lasers or amplifiers.

  10. OSCAR experiment high-density network data report: Event 4 - April 21-23, 1981

    SciTech Connect

    Dana, M.T.; Easter, R.C.; Thorp, J.M.

    1984-12-01

    The OSCAR (Oxidation and Scavenging Characteristics of April Rains) experiment, conducted during April 1981, was a cooperative field investigation of wet removal in cyclonic storm systems. The high-density component of OSCAR was located in northeast Indiana and included sequential precipitation chemistry measurements on a 100 by 100 km netwok, as well as airborne air chemistry and cloud chemistry mueasurements, surface air chemistry measurements, and supporting meteorological measurements. Four separate storm events were studied during the experiment. This report summarizes data taken by Pacific Northwest Laboratory (PNL) during the fourth storm event, April 21-23. The report contains the high-density network precipitation chemistry data, air and cloud chemistry data from the two PNL aircraft, and meteorological data for the event, including standard National Weather Service products and radar and rawindsonde data from the event. 3 references, 80 figures, 11 tables.

  11. Compatibility of fuel-system components with high density fuel. Final report, April 1987-January 1989

    SciTech Connect

    Grenich, A.F.; Johnson, A.M.

    1989-05-01

    Environmental and endurance tests were conducted to evaluate the performance of typical fuel-system components when exposed to high-density aviation turbine engine fuel. The environment tests simulated the extreme high and low temperatures encountered in hot- and cold-day missions. The results revealed that the high-density fuel (HDF) would not have any fuel boiling or freezing problems but the pump power required for HDF was higher than for JP-4 fuel as was expected and the lower heat capacity of HDF resulted in noticeably higher heat-exchanger discharge temperatures. The endurance tests revealed that the HDF would not cause abnormal wear or component leakage. Nothing in the test results suggested that current inputs to fuel-system life-cycle-cost models should be modified if HDF is used.

  12. High-Density Reconstitution of Functional Water Channels into Vesicular and Planar Block Copolymer Membranes

    PubMed Central

    2012-01-01

    The exquisite selectivity and unique transport properties of membrane proteins can be harnessed for a variety of engineering and biomedical applications if suitable membranes can be produced. Amphiphilic block copolymers (BCPs), developed as stable lipid analogs, form membranes that functionally incorporate membrane proteins and are ideal for such applications. While high protein density and planar membrane morphology are most desirable, BCP–membrane protein aggregates have so far been limited to low protein densities in either vesicular or bilayer morphologies. Here, we used dialysis to reproducibly form planar and vesicular BCP membranes with a high density of reconstituted aquaporin-0 (AQP0) water channels. We show that AQP0 retains its biological activity when incorporated at high density in BCP membranes, and that the morphology of the BCP–protein aggregates can be controlled by adjusting the amount of incorporated AQP0. We also show that BCPs can be used to form two-dimensional crystals of AQP0. PMID:23082933

  13. Advantages and Challenges of 10-Gbps Transmission on High-Density Interconnect Boards

    NASA Astrophysics Data System (ADS)

    Yee, Chang Fei; Jambek, Asral Bahari; Al-Hadi, Azremi Abdullah

    2016-03-01

    This paper provides a brief introduction to high-density interconnect (HDI) technology and its implementation on printed circuit boards (PCBs). The advantages and challenges of implementing 10-Gbps signal transmission on high-density interconnect boards are discussed in detail. The advantages (e.g., smaller via dimension and via stub removal) and challenges (e.g., crosstalk due to smaller interpair separation) of HDI are studied by analyzing the S-parameter, time-domain reflectometry (TDR), and transmission-line eye diagrams obtained by three-dimensional electromagnetic modeling (3DEM) and two-dimensional electromagnetic modeling (2DEM) using Mentor Graphics HyperLynx and Keysight Advanced Design System (ADS) electronic computer-aided design (ECAD) software. HDI outperforms conventional PCB technology in terms of signal integrity, but proper routing topology should be applied to overcome the challenge posed by crosstalk due to the tight spacing between traces.

  14. Equations of state for many-body systems at high densities

    NASA Astrophysics Data System (ADS)

    Khan, Imran; Gao, Bo

    2004-05-01

    For a many-body system at high densities, the equation of state depends not only on the scattering length, but also on further details of the inter-particle potential. For a many-atom system, in particular, its behavior at high densities will depend on the van der Waals interaction. We are exploring the behavior of a many-atom system in this density regime using the variational Monte Carlo method, in combination with the concept of effective potential introduced in a recent work(B. Gao, J. Phys. B 36), 2111 (2003).. As an initial test, we will compare our hard-sphere results with those of Gross-Pitevaskii equation and diffussion Monte Carlo method(D. Blume and C. H. Greene, Phys. Rev. A 63), 063601 (2001)..

  15. Purification of very high density lipoproteins by differential density gradient ultracentrifugation.

    PubMed

    Haunerland, N H; Ryan, R O; Law, J H; Bowers, W S

    1987-03-01

    Differential density gradient ultracentrifugation procedures, utilizing a vertical rotor, were developed for the preparative purification of very high density lipoproteins (VHDL, density greater than 1.21 g/ml). The VHDLs of several insect species were purified as follows. An initial density gradient ultracentrifugation step removed lipoproteins of lower density from the VHDL-fraction, which partially separated from the nonlipoproteins present in the infranatant. A complete separation was achieved by a second centrifugation step employing a modified gradient system. The use of a vertical rotor and specially designed discontinuous gradients allows a relatively fast, efficient, and economical isolation of the class of very high density lipoproteins. Similar gradient systems should be useful for the detection and purification of VHDLs from other sources. PMID:3578796

  16. A very-high-density lipoprotein with clotting ability from hemolymph of sand crayfish, Ibacus ciliatus.

    PubMed

    Komatsu, M; Ando, S

    1998-03-01

    A very-high-density lipoprotein (VHDL) with a density of 1.27-1.29 g/ml was the most abundant lipoprotein in the hemolymph of the sand crayfish Ibacus ciliatus. The VHDL isolated by a density gradient ultracentrifugation consisted of 94% protein and 6% lipid reflecting its high density, and phospholipid was a predominant lipid component. The VHDL had an apolipoprotein of molecular mass 195 kDa and its N-terminal amino acid sequence was identified as follows: LQPGLEYQYRYNGRVAA. This sequence was similar to those of clotting proteins from the spiny lobster Panulirus interruptus and the freshwater crayfish Pacifastacus leniusculus. Transglutaminase and Ca2+ also induced the VHDL to clot. Considering large amounts of VHDL in the hemolymph of sand crayfish, the VHDL not only functions as lipid carrier but plays an important role in the defense process of crustacea. PMID:9571775

  17. Effects of high-density lipoproteins on storage at 4 degrees C of fowl spermatozoa.

    PubMed

    Blesbois, E; Hermier, D

    1990-11-01

    Qualitative and quantitative characterization of lipoproteins found in seminal plasma from domestic cocks was performed after isolation by density gradient ultracentrifugation. Trigyceride-rich lipoproteins (very low, intermediate- and low density lipoproteins) were not detectable in seminal plasma. High-density lipoproteins (HDL), identified on the basis of size, chemical composition and protein moiety, were present at a concentration of 66 micrograms/ml. A fraction possibly corresponding to VHDL (very high density lipoproteins, 77% protein, 23% lipid) was also detected but appeared contaminated by a protein-rich opalescent material. Since HDL contains mostly phospholipid and cholesterol, the physiological role of these lipoproteins on the storage of fowl spermatozoa was studied. Replacing seminal plasma with a solution containing chicken HDL at physiological concentration (66 micrograms/ml) had no effect on fertilizing ability of spermatozoa stored at 4 degrees C for 24 h. However, higher concentrations of HDL (560 micrograms/ml) had deleterious effects on spermatozoa stored in vitro. PMID:2250247

  18. Low Pressure High Density Plasma Development on a Small Helicon Plasma Experiment (HPX)*

    NASA Astrophysics Data System (ADS)

    James, R. W.; Allen, L. A.; Paolino, R. N.; Thayer, N.; Romano, B.; Stutzman, B. S.; Welicka, C.; Coast Guard Plasma Lab Team

    2011-10-01

    Small helicon plasmas have been employed in various capacities from industry to spacecraft propulsion. At the Coast Guard Academy Plasma Lab (CGAPL), a small Helicon Plasma Experiment (HPX) is being developed to utilize the reputed high densities (1013 cm-3 and higher) at low pressure (.01 T), in high temperature and density diagnostic development for future laboratory investigations. HPX is designed to operate at these high densities and pressure to create repeatedly stable Capacitively Coupled Plasma (CCP) and Inductively Coupled Plasma (ICP) plasmas induced by an RF frequency in the 10 to 70 MHz range. Progress on the development of the RF coupling system, and qualitative observations from the optical and electric diagnostics are to be reported.

  19. High-density ferroelectric recording using a hard disk drive-type data storage system

    NASA Astrophysics Data System (ADS)

    Aoki, Tomonori; Hiranaga, Yoshiomi; Cho, Yasuo

    2016-05-01

    Ferroelectric probe data storage has been proposed as a novel data storage method in which bits are recorded based on the polarization directions of individual domains. These bits are subsequently read by scanning nonlinear dielectric microscopy. The domain walls of typical ferroelectric materials are quite thin: often only several times the lattice constant, which is advantageous for high-density data storage. In this work, high-density read/write (R/W) demonstrations were conducted using a hard disk drive-type test system, and the writing of bit arrays with a recording density of 3.4 Tbit/in.2 was achieved. Additionally, a series of writing and reading operations was successfully demonstrated at a density of 1 Tbit/in.2. Favorable characteristics of ferroelectric recording media for use with the proposed method are discussed in the latter part of this paper.

  20. Production of centimeter-scale, high-density plasmas with a linear gas jet

    SciTech Connect

    Coverdale, C.A.; Darrow, C.B.; Jones, R.; Sawyer, W.; Crane, J.; Ditmire, T.; Perry, M.D. ); Filbert, P.C. )

    1995-01-01

    A novel linear gas jet has been developed and used to produce centimeter-scale, 10[sup 19] cm[sup [minus]3] electron density plasmas. Long regions of high density are important to many types of experiments, including x-ray laser and laser-plasma interaction studies. This new type of gas jet has been characterized by stimulated Raman backscatter emission from the plasma.

  1. Ultra-high density standard cell library using multi-height cell structure

    NASA Astrophysics Data System (ADS)

    Baek, Sang-Hoon; Kim, Ha-Young; Lee, Young-Keun; Jin, Duck-Yang; Park, Se-Chang; Cho, Jun-Dong

    2008-12-01

    As the market size of mobile products is enlarged, low power and high density design in integrated chips are demanding. To meet these market demands, "ultra high density" (UHD) standard cell library becomes essential to further reduce the chip size. Furthermore, to enhance the density of standard cell library especially at 90nm and below, the conventional methods of reducing cell height is not sufficient to meet the density constraints. Motivated by the fact, in this paper, we devise a flexible design technique of UHD library with the multi-height cell structure. Each cell of conventional standard cell libraries with one-layer metal routing has the same cell height. However, multi-height cell library with two-layer metal routing has two types of cell structure: 1) Simple cells (e.g. inverter, nand, nor, etc.) are structured with single height; 2) Complex cells (e.g. flip-flop, latch, mux, etc.) are structured with double height. In this double height cell structure, Metal2 layer is used for power line. Therefore, Metal1 and G-ploy are routed vertically, gaining more Metal1 routing space, and thus we can attain more effective design for manufacturability (DFM). Also, by doing so, design time is reduced while achieving better layout efficiency. We tested logic circuits with 700,000 gates using 90nm technology to compare our new UHD library with existing high density library. Our experimental results show that each of 26 cells (frequently used) is shrunk by 14.29 ~ 26.98%. Furthermore, chip size is shrunk by 13.90 ~ 15.65% compared with high density library.

  2. Facile route to high-density, ordered ZnO nanowire arrays and their photoluminescence properties

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Tao, Xiaoming; Liu, Yuyang; Sun, Xiaohong; Hu, Zhigang; Fei, Bin

    2006-10-01

    A simple template-directed wet chemistry route based on traditional thermal decomposition technique has been developed for the preparation of high-density, ordered ZnO nanowire arrays. The fabrication was performed at relative low temperature without involving complex procedures, sophisticated equipment and rigorous experiment conditions, thereby providing a straightforward and mild method to produce metal/metal oxide ordered nanostructures. The nanowire array system was evaluated by SEM, XRD, TEM and PL. A stable luminescence at 425 nm was present.

  3. High-density capacitors pack more energy in a smaller space

    NASA Astrophysics Data System (ADS)

    Lerner, E. J.

    1985-05-01

    Attention is given to the design features and performance characteristics of novel high density capacitor banks which furnish a tenfold energy increase over conventional capacitors, to values of the order of 100 J/kg or 0.28 J/cu cm. The essential feature of the new design is the replacement of plastic dielectric films interleaved with oil-soaked films by a paperless film system that uses perfluorocarbon rather than oil.

  4. High-density implosion via suppression of Rayleigh–Taylor instability

    NASA Astrophysics Data System (ADS)

    Shiroto, Takashi; Ohnishi, Naofumi; Sunahara, Atsushi; Fujioka, Shinsuke; Sasaki, Akira

    2016-05-01

    Radiation hydrodynamic simulations of ICF capsules assuming a kJ-class laser facility were conducted to evaluate the hydrodynamic stability of a brominated plastic shell. An opacity table based on a detailed atomic model was employed so that more quantitative forecast of the implosion dynamics could be performed. A lightly doped shell could form a high-density core at the maximum compression by suppressing the hydrodynamic instability.

  5. 250 degrees C SiC High Density Power Module Development

    SciTech Connect

    Ning, Puqi; Wang, Fei; Ngo, Khai

    2011-01-01

    Taking full advantage of SiC devices, a team from Oak Ridge National Laboratory, the University of Tennessee and Virginia Polytechnic Institute and State University have designed, developed, and tested a phase-leg power module based on a high temperature wirebond package. Details of the layout, gate drive, and cooling system designs are described. Continuous power tests confirmed that our design process produced a high density power module that operated successfully at high junction temperatures.

  6. Tris(triazolo)benzene and its derivatives: high-density energetic materials.

    PubMed

    Thottempudi, Venugopal; Forohor, Farhad; Parrish, Damon A; Shreeve, Jean'ne M

    2012-09-24

    High-performance explosives: Tris(triazolo)benzene was synthesized and converted to its trinitro and trichloro derivatives (see scheme; R=NO(2), Cl). The heats of formation of this "high-nitrogen" compounds were calculated and combined with experimentally determined densities to determine detonation pressures and velocities. They exhibit high density, good thermal stability, high heats of formation, and moderate to good detonation properties. PMID:22945830

  7. Practical high-density shielding materials for medical linear accelerator rooms.

    PubMed

    Barish, R J

    1990-01-01

    High-energy linear accelerators are replacing lower energy units in radiation therapy centers. Radiation protection requirements necessitate expensive reconstruction of existing treatment rooms to accommodate these new machines. We describe two shielding materials: one made by embedding small pieces of scrap steel in cement, and the other made with cast iron in cement. Both materials produce high-density barriers at low cost using standard construction methods. PMID:2294072

  8. Acoustical Detection of High-Density Krill Demersal Layers in the Submarine Canyons off Georges Bank.

    PubMed

    Greene, C H; Wiebe, P H; Burczynski, J; Youngbluth, M J

    1988-07-15

    High-density demersal layers of krill have been detected in the submarine canyons off Georges Bank by means of a high-frequency, dual-beam bioacoustical technique. Krill densities in these demersal layers were observed to be two to three orders of magnitude greater than the highest densities observed in water-column scattering layers. Such abundances may help explain the unusually high squid and demersal fish production estimates attributed to the Georges Bank ecosystem. PMID:17734865

  9. Growth and characterization of high-density mats of single-walled carbon nanotubes for interconnects

    SciTech Connect

    Robertson, J.; Zhong, G.; Telg, H.; Thomsen, C.; Warner, J. H.; Briggs, G. A. D.; Dettlaff-Weglikowska, U.; Roth, S.

    2008-10-20

    We grow high-density, aligned single wall carbon nanotube mats for use as interconnects in integrated circuits by remote plasma chemical vapor deposition from a Fe-Al{sub 2}O{sub 3} thin film catalyst. We carry out extensive Raman characterization of the resulting mats, and find that this catalyst system gives rise to a broad range of nanotube diameters, with no preferential selectivity of semiconducting tubes, but with at least 1/3 of metallic tubes.

  10. Hydrogen Filling Station

    SciTech Connect

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    future. Project partners also conducted a workshop on hydrogen safety and permitting. This provided an opportunity for the various permitting agencies and end users to gather to share experiences and knowledge. As a result of this workshop, the permitting process for the hydrogen filling station on the Las Vegas Valley Water District’s land was done more efficiently and those who would be responsible for the operation were better educated on the safety and reliability of hydrogen production and storage. The lessons learned in permitting the filling station and conducting this workshop provided a basis for future hydrogen projects in the region. Continuing efforts to increase the working pressure of electrolysis and efficiency have been pursued. Research was also performed on improving the cost, efficiency and durability of Proton Exchange Membrane (PEM) hydrogen technology. Research elements focused upon PEM membranes, electrodes/catalysts, membrane-electrode assemblies, seals, bipolar plates, utilization of renewable power, reliability issues, scale, and advanced conversion topics. Additionally, direct solar-to-hydrogen conversion research to demonstrate stable and efficient photoelectrochemistry (PEC) hydrogen production systems based on a number of optional concepts was performed. Candidate PEC concepts included technical obstacles such as inefficient photocatalysis, inadequate photocurrent due to non-optimal material band gap energies, rapid electron-hole recombination, reduced hole mobility and diminished operational lifetimes of surface materials exposed to electrolytes. Project Objective 1: Design, build, operate hydrogen filling station Project Objective 2: Perform research and development for utilizing solar technologies on the hydrogen filling station and convert two utility vehicles for use by the station operators Project Objective 3: Increase capacity of hydrogen filling station; add additional vehicle; conduct safety workshop; develop a roadmap for

  11. High density mode in xenon produced by a Helicon Double Layer Thruster

    NASA Astrophysics Data System (ADS)

    West, Michael D.; Charles, Christine; Boswell, Rod W.

    2009-12-01

    A high density 'blue' mode has been observed when operating the Helicon Double Layer Thruster (HDLT) with xenon. Using a Langmuir probe and a retarding field energy analyser (RFEA), the plasma source and exhaust have been characterized at various radio frequency (RF) powers and operating pressures. When operating at low RF powers, the HDLT prototype is shown to be in a capacitively coupled mode. As the RF power is increased, a discrete mode transition occurs over a small RF power range (at about 625 W at 0.45 mTorr) and the plasma inside the source increases in density significantly and changes to a bright white/blue colour. This high density mode exhibits hysteresis, and radial measurements inside the source reveal a centrally peaked profile that is indicative of a helicon wave-sustained discharge. The quality, or Q, factor of the matching box is determined as a function of RF power and is shown to decrease in the high density mode, consistent with the increase in plasma density observed. The xenon exhaust of the HDLT prototype is investigated axially with the Langmuir probe and the RFEA and is shown to follow a Boltzmann expansion with an electron temperature of about 6 eV.

  12. Injectable, high-density collagen gels for annulus fibrosus repair: An in vitro rat tail model.

    PubMed

    Borde, Brandon; Grunert, Peter; Härtl, Roger; Bonassar, Lawrence J

    2015-08-01

    A herniated intervertebral disc often causes back pain when disc tissue is displaced through a damaged annulus fibrosus. Currently, the only methods available for annulus fibrosus repair involve mechanical closure of defect, which does little to address biological healing in the damaged tissue. Collagen hydrogels are injectable and have been used to repair annulus defects in vivo. In this study, high-density collagen hydrogels at 5, 10, and 15 mg/mL were used to repair defects made to intact rat caudal intervertebral discs in vitro. A group of gels at 15 mg/mL were also cross-linked with riboflavin at 0.03 mM, 0.07 mM, or 0.10 mM. These cross-linked, high-density collagen gels maintained their presence in the defect under loading and contributed positively to the mechanical response of damaged discs. Discs exhibited increases to 95% of undamaged effective equilibrium and instantaneous moduli as well as up to fourfold decreases in effective hydraulic permeability from the damaged discs. These data suggest that high-density collagen gels may be effective at restoring mechanical function of injured discs as well as potential vehicles for the delivery of biological agents such as cells or growth factors that may aid in the repair of the annulus fibrosus. PMID:25504661

  13. Nucleation of ordered solid phases of proteins via a disordered high-density state: Phenomenological approach

    NASA Astrophysics Data System (ADS)

    Pan, Weichun; Kolomeisky, Anatoly B.; Vekilov, Peter G.

    2005-05-01

    Nucleation of ordered solid phases of proteins triggers numerous phenomena in laboratory, industry, and in healthy and sick organisms. Recent simulations and experiments with protein crystals suggest that the formation of an ordered crystalline nucleus is preceded by a disordered high-density cluster, akin to a droplet of high-density liquid that has been observed with some proteins; this mechanism allowed a qualitative explanation of recorded complex nucleation kinetics curves. Here, we present a simple phenomenological theory that takes into account intermediate high-density metastable states in the nucleation process. Nucleation rate data at varying temperature and protein concentration are reproduced with high fidelity using literature values of the thermodynamic and kinetic parameters of the system. Our calculations show that the growth rate of the near-critical and supercritical ordered clusters within the dense intermediate is a major factor for the overall nucleation rate. This highlights the role of viscosity within the dense intermediate for the formation of the ordered nucleus. The model provides an understanding of the action of additives that delay or accelerate nucleation and presents a framework within which the nucleation of other ordered protein solid phases, e.g., the sickle cell hemoglobin polymers, can be analyzed.

  14. Novel LLM series high density energy materials: Synthesis, characterization, and thermal stability

    NASA Astrophysics Data System (ADS)

    Pagoria, Philip; Zhang, Maoxi; Tsyshevskiy, Roman; Kuklja, Maija

    Novel high density energy materials must satisfy specific requirements, such as an increased performance, reliably high stability to external stimuli, cost-efficiency and ease of synthesis, be environmentally benign, and be safe for handling and transportation. During the last decade, the attention of researchers has drifted from widely used nitroester-, nitramine-, and nitroaromatic-based explosives to nitrogen-rich heterocyclic compounds. Good thermal stability, the low melting point, high density, and moderate sensitivity make heterocycle materials attractive candidates for use as oxidizers in rocket propellants and fuels, secondary explosives, and possibly as melt-castable ingredients of high explosive formulations. In this report, the synthesis, characterization, and results of quantum-chemical DFT study of thermal stability of LLM-191, LLM-192 and LLM-200 high density energy materials are presented. Work performed under the auspices of the DOE by the LLNL (Contract DE-AC52-07NA27344). This research is supported in part by ONR (Grant N00014-12-1-0529) and NSF. We used NSF XSEDE (Grant DMR-130077) and DOE NERSC (Contract DE-AC02-05CH11231) resources.

  15. HIGH-DENSITY MOLECULAR GAS PROPERTIES OF THE STARBURST GALAXY NGC 1614 REVEALED WITH ALMA

    SciTech Connect

    Imanishi, Masatoshi; Nakanishi, Kouichiro

    2013-09-15

    We present the results of HCN/HCO{sup +}/HNC J = 4-3 transition line observations of the nearby starburst galaxy NGC 1614, obtained with ALMA Cycle 0. We find that high density molecular gas traced with these lines shows a velocity structure such that the northern (southern) side of the nucleus is redshifted (blueshifted) with respect to the nuclear velocity of this galaxy. The redshifted and blueshifted emission peaks are offset by {approx}0.''6 at the northern and southern sides of the nucleus, respectively. At these offset positions, observations at infrared >3 {mu}m indicate the presence of active dusty starbursts, supporting the picture that high-density molecular gas is the site of active starbursts. The enclosed dynamical mass within the central {approx}2'' in radius, derived from the dynamics of the high-density molecular gas, is {approx}10{sup 9} M{sub Sun }, which is similar to previous estimates. Finally, the HCN emission is weaker than HCO{sup +} but stronger than HNC for J = 4-3 for all starburst regions of NGC 1614, as seen for J = 1-0 transition lines in starburst-dominated galaxies.

  16. Monitoring underground water quality based on high-density resistivity method

    NASA Astrophysics Data System (ADS)

    Xu, Yanyan

    2015-12-01

    Underground water is different from surface water. Once contaminated, underground water is difficult to recover, so it is necessary to give priority to the prevention of the quality of underground water. High-density resistivity method is very important in the environmental engineering geophysical prospecting and it is widely used in mineral resources as well as monitoring the underground-water quality. In the experiment, multi-tools joint inversion is applied to build the model in order to increase the accuracy. In contrast with the pollution-free water model which is owned by the RES2DMOD, the inversion result of underground water quality with the high density resistivity method is useful to monitor the underground water quality, showing that different degree of water pollution depends on the position of abnormal and there is a more significant abnormal value in the vertical direction of the deep abnormal than that of the shallow abnormal, and high and low resistance pollution depends on the different value and forms of abnormal resistance. In conclusion, monitoring the underground water quality by the high density resistivity method is efficient. In the future research, it is necessary to accomplish more precise inversion models combining with field measurements to find out the optimal solution to monitor underwater quality.

  17. Investigation of photon shielding property changes in curing high density concrete.

    PubMed

    Marsh, Matthew B; Peters, Christopher; Rawluk, Nicholas; Schreiner, L John

    2013-10-01

    High density concrete is usually used for radiation shielding around radiotherapy treatment rooms. Because the concrete is specified differently at the design, construction, and verification stages, the relationship between the intended performance and the actual performance of the shielding material might not be entirely clear. In this study, cylindrical samples of high density shielding concrete were taken as each section of a new radiotherapy bunker was poured. The shielding performance of each sample [measured by beam attenuation and tenth-value layers (TVL)] was evaluated for 15 MV and 6 MV x-ray beams and for the 1.25 MeV monoenergetic gamma beam from a Co source. Transmission curves to 3 TVL were mapped for a representative sample. The samples were also imaged and analyzed using Co Cone Beam Computed Tomography (CoCBCT). Results indicate no significant change in the TVL of high density concrete samples as they cure. The minor fluctuations in shielding properties observed are explained by the heterogeneous structure of the samples as indicated in the CoCBCT images. PMID:23982607

  18. Enhanced delivery of lipophilic nutrients to the infant brain via high density lipoprotein.

    PubMed

    Naberhuis, J K; Lai, C-S

    2015-11-01

    Lipoproteins are the primary carriers of lipophilic cognitive nutrients such as docosahexaenoic acid, lutein, and α-tocopherol within circulation. The critical roles these nutrients play in growth and development are well established, and as such, their efficient delivery to the infant brain is crucial. Given the selectivity of the blood brain barrier, the lipoprotein fraction primarily responsible for brain delivery of these nutrients must be determined so that efforts aimed at increasing brain nutrient uptake, via lipoprotein profile manipulation, can be appropriately focused. Based on the preclinical and clinical data reviewed here, we hypothesize that high density lipoprotein is the fraction chiefly responsible for delivery of docosahexaenoic acid, lutein, and α-tocopherol to the infant brain. As high density lipoprotein levels tend to be lower in preterm, formula-fed infants as compared to their full-term, breast-fed counterparts, efforts aimed at increasing circulating high density lipoprotein levels, and subsequent delivery of cognitive lipophilic nutrients to the brain via manipulation of formula composition, may be most effective if targeted to this group. These efforts include (1) limiting the polyunsaturated: saturated fatty acid ratio; (2) increasing the casein: whey ratio; (3) altering the proportion of saturated fatty acids found in the sn-2 position of the parent triglyceride; (4) cholesterol supplementation; and (5) nucleotide supplementation. PMID:26323246

  19. X-ray CT high-density artefact suppression in the presence of bones

    NASA Astrophysics Data System (ADS)

    Wei, Jikun; Chen, Laigao; Sandison, George A.; Liang, Yun; Xu, Lisa X.

    2004-12-01

    This paper presents a novel method of reducing x-ray CT high-density artefacts generated by metal objects when abundant bone structures are present in the region of interest. This method has an advantage over previously proposed methods since it heavily suppresses the metal artefacts without introducing extra bone artefacts. The method of suppression requires that bone pixels are isolated and segmented by thresholding. Then artificial CT numbers are assigned to the bone pixels so that their projection profiles are smooth and thus can be properly simulated by a polynomial interpolation. The projection profile of the metal object is then removed to fully suppress the artefacts. The resulting processed profile is fed to a reconstruction routine and the previously preserved bone pixels added back. The new method utilizes two important features of the CT image with metal artefacts: (a) metal and bone pixels are not severely affected by the high-density artefacts and (b) the high-density artefacts can be located in specific projection channels in the profile domain, although they are spread out in the image domain. This suppression method solves the problem of CT image artefacts arising from metal objects in the body. It has the potential to greatly improve diagnostic CT imaging in the presence of these objects and treatment planning that utilizes CT for patients with metal applicators (e.g., brachytherapy for cervix cancer and prostate cryotherapy).

  20. Synthesis of high density aviation fuel with cyclopentanol derived from lignocellulose

    NASA Astrophysics Data System (ADS)

    Sheng, Xueru; Li, Ning; Li, Guangyi; Wang, Wentao; Yang, Jinfan; Cong, Yu; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

    2015-03-01

    For the first time, renewable high density aviation fuels were synthesized at high overall yield (95.6%) by the Guerbet reaction of cyclopentanol which can be derived from lignocellulose, followed by the hydrodeoxygenation (HDO). The solvent-free Guerbet reaction of cyclopentanol was carried out under the co-catalysis of solid bases and Raney metals. Among the investigated catalyst systems, the combinations of magnesium-aluminium hydrotalcite (MgAl-HT) and Raney Ni (or Raney Co) exhibited the best performances. Over them, high carbon yield (96.7%) of C10 and C15 oxygenates was achieved. The Guerbet reaction products were further hydrodeoxygenated to bi(cyclopentane) and tri(cyclopentane) over a series of Ni catalysts. These alkanes have high densities (0.86 g mL-1 and 0.91 g mL-1) and can be used as high density aviation fuels or additives to bio-jet fuel. Among the investigated HDO catalysts, the 35 wt.% Ni-SiO2-DP prepared by deposition-precipitation method exhibited the highest activity.

  1. Optimal Thermo-Structural Analysis for High Density Package Mounting on Build-up Board

    NASA Astrophysics Data System (ADS)

    Nakanishi, Tohru; Hase, Tomohiro

    The importance of the high density packaging technology and mounting technology on the printed wiring build-up board has been increased for the consumer electric products. On the other hand, the chance to use the build-up boards for mounting the high density packages has been increased. However, the understanding that the reliability of the solder connection depends on the structure of the package, the motherboard, and the material properties, is not very high. In this paper, the reliability for high density packaging, mounted on the build-up board, is assessed. The compact numerical analysis model for the reliability assessment is suggested and the most reliable packaging design with optimizing each of the parameters is reported. For introduction to the reliability assessment of the FCA attachment, ceramic and silicon are compared as the inter-poser with the parameter of the solder height. The verification of the numerical analysis results using tests on the actual hardware is also shown. And the established numerical analysis model is applied to the study of influence of the copper balance between the front side and the back side copper layers.

  2. A new algorithm for fluid simulation of high density plasma discharges

    NASA Astrophysics Data System (ADS)

    Oh, Seon-Geun; Lee, Young-Jun; Choe, Heehwan; Jeon, Jae-Hong; Seo, Jong-Hyun

    2013-10-01

    Low temperature, high density plasma sources are widely used for the electronic device fabrications such as semiconductor, flat panel display, and solar cell. The inductively coupled plasma or the capacitively coupled plasma reactors are typical ones in these processes. Fluid simulation is one of the methods for transport modeling of high density discharge, because the profiles of plasma quantities are easily obtained. The short shielding time scale of an electric field perturbation is a major restriction on the simulation time step. In most cases, the simulation time step in the explicit method is less than 10-13 sec. To overcome this limitation, a new method for steady-state fluid simulation of high density plasma discharge is suggested. Following the physical origin of restriction on simulation time step, a new method is developed using both analytic and numerical methods. A simple application of the new method with previously known one is given to study the validity of the method. This work was supported in part by the International collaborative R&D program (N0000678), and by the Industrial Strategic Technology Development Program (10041681) funded by the Ministry of Trade, Industry and Energy (MOTIE, Korea).

  3. Construction and Analysis of High-Density Linkage Map Using High-Throughput Sequencing Data

    PubMed Central

    Liu, Min; Liu, Hui; Zeng, Huaping; Deng, Dejing; Xin, Huaigen; Song, Jun; Xu, Chunhua; Sun, Xiaowen; Hou, Xilin; Wang, Xiaowu; Zheng, Hongkun

    2014-01-01

    Linkage maps enable the study of important biological questions. The construction of high-density linkage maps appears more feasible since the advent of next-generation sequencing (NGS), which eases SNP discovery and high-throughput genotyping of large population. However, the marker number explosion and genotyping errors from NGS data challenge the computational efficiency and linkage map quality of linkage study methods. Here we report the HighMap method for constructing high-density linkage maps from NGS data. HighMap employs an iterative ordering and error correction strategy based on a k-nearest neighbor algorithm and a Monte Carlo multipoint maximum likelihood algorithm. Simulation study shows HighMap can create a linkage map with three times as many markers as ordering-only methods while offering more accurate marker orders and stable genetic distances. Using HighMap, we constructed a common carp linkage map with 10,004 markers. The singleton rate was less than one-ninth of that generated by JoinMap4.1. Its total map distance was 5,908 cM, consistent with reports on low-density maps. HighMap is an efficient method for constructing high-density, high-quality linkage maps from high-throughput population NGS data. It will facilitate genome assembling, comparative genomic analysis, and QTL studies. HighMap is available at http://highmap.biomarker.com.cn/. PMID:24905985

  4. Neonatal hemodynamic response to visual cortex activity: high-density near-infrared spectroscopy study

    NASA Astrophysics Data System (ADS)

    Liao, Steve M.; Gregg, Nick M.; White, Brian R.; Zeff, Benjamin W.; Bjerkaas, Katelin A.; Inder, Terrie E.; Culver, Joseph P.

    2010-03-01

    The neurodevelopmental outcome of neonatal intensive care unit (NICU) infants is a major clinical concern with many infants displaying neurobehavioral deficits in childhood. Functional neuroimaging may provide early recognition of neural deficits in high-risk infants. Near-infrared spectroscopy (NIRS) has the advantage of providing functional neuroimaging in infants at the bedside. However, limitations in traditional NIRS have included contamination from superficial vascular dynamics in the scalp. Furthermore, controversy exists over the nature of normal vascular, responses in infants. To address these issues, we extend the use of novel high-density NIRS arrays with multiple source-detector distances and a superficial signal regression technique to infants. Evaluations of healthy term-born infants within the first three days of life are performed without sedation using a visual stimulus. We find that the regression technique significantly improves brain activation signal quality. Furthermore, in six out of eight infants, both oxy- and total hemoglobin increases while deoxyhemoglobin decreases, suggesting that, at term, the neurovascular coupling in the visual cortex is similar to that found in healthy adults. These results demonstrate the feasibility of using high-density NIRS arrays in infants to improve signal quality through superficial signal regression, and provide a foundation for further development of high-density NIRS as a clinical tool.

  5. A high-density genetic map and growth related QTL mapping in bighead carp (Hypophthalmichthys nobilis)

    PubMed Central

    Fu, Beide; Liu, Haiyang; Yu, Xiaomu; Tong, Jingou

    2016-01-01

    Growth related traits in fish are controlled by quantitative trait loci (QTL), but no QTL for growth have been detected in bighead carp (Hypophthalmichthys nobilis) due to the lack of high-density genetic map. In this study, an ultra-high density genetic map was constructed with 3,121 SNP markers by sequencing 117 individuals in a F1 family using 2b-RAD technology. The total length of the map was 2341.27 cM, with an average marker interval of 0.75 cM. A high level of genomic synteny between our map and zebrafish was detected. Based on this genetic map, one genome-wide significant and 37 suggestive QTL for five growth-related traits were identified in 6 linkage groups (i.e. LG3, LG11, LG15, LG18, LG19, LG22). The phenotypic variance explained (PVE) by these QTL varied from 15.4% to 38.2%. Marker within the significant QTL region was surrounded by CRP1 and CRP2, which played an important role in muscle cell division. These high-density map and QTL information provided a solid base for QTL fine mapping and comparative genomics in bighead carp. PMID:27345016

  6. The elastic and yield behavior of polyethylene tubes subjected to biaxial loadings

    NASA Technical Reports Server (NTRS)

    Tuttle, M. E.; Semeliss, M.; Wong, R.

    1992-01-01

    The elastic and yield response of extruded thin-walled high-density polyethylene tubes with a density in the range of 0.961 to 0.964 gm/cu cm was investigated. Material properties in the axial and hoop directions were measured, and the tubes were found to be mildly transversely isotropic. The yield response was pressure sensitive, and was well predicted using the pressure-modified Hill criterion using a compressive to tensile yield strength ratio of 1:12.

  7. Single electron states in polyethylene

    SciTech Connect

    Wang, Y.; MacKernan, D.; Cubero, D. E-mail: n.quirke@imperial.ac.uk; Coker, D. F.; Quirke, N. E-mail: n.quirke@imperial.ac.uk

    2014-04-21

    We report computer simulations of an excess electron in various structural motifs of polyethylene at room temperature, including lamellar and interfacial regions between amorphous and lamellae, as well as nanometre-sized voids. Electronic properties such as density of states, mobility edges, and mobilities are computed on the different phases using a block Lanczos algorithm. Our results suggest that the electronic density of states for a heterogeneous material can be approximated by summing the single phase density of states weighted by their corresponding volume fractions. Additionally, a quantitative connection between the localized states of the excess electron and the local atomic structure is presented.

  8. Single electron states in polyethylene

    NASA Astrophysics Data System (ADS)

    Wang, Y.; MacKernan, D.; Cubero, D.; Coker, D. F.; Quirke, N.

    2014-04-01

    We report computer simulations of an excess electron in various structural motifs of polyethylene at room temperature, including lamellar and interfacial regions between amorphous and lamellae, as well as nanometre-sized voids. Electronic properties such as density of states, mobility edges, and mobilities are computed on the different phases using a block Lanczos algorithm. Our results suggest that the electronic density of states for a heterogeneous material can be approximated by summing the single phase density of states weighted by their corresponding volume fractions. Additionally, a quantitative connection between the localized states of the excess electron and the local atomic structure is presented.

  9. Poly(ethylene oxide) functionalization

    DOEpatents

    Pratt, Russell Clayton

    2014-04-08

    A simple procedure is provided by which the hydroxyl termini of poly(ethylene oxide) can be appended with functional groups to a useful extent by reaction and precipitation. The polymer is dissolved in warmed toluene, treated with an excess of organic base and somewhat less of an excess of a reactive acylating reagent, reacted for several hours, then precipitated in isopropanol so that the product can be isolated as a solid, and salt byproducts are washed away. This procedure enables functionalization of the polymer while not requiring laborious purification steps such as solvent-solvent extraction or dialysis to remove undesirable side products.

  10. Filling the launch gap

    NASA Astrophysics Data System (ADS)

    Hoeser, S.

    1986-05-01

    Vehicles proposed to fill the gap in the U.S. space program's space transport needs for the next decade resulting from the January Challenger disaster, are discussed. Prior to the accident, the Air Force planned to purchase a Complementary Expendable Launch Vehicle system consisting of 10 single-use Titan-34D7 rockets. Another heavy lift booster now considered is the Phoenix H. Commercial launch vehicle systems projected to be available in the necessary time frame include the 215,000-pound thrust 4000-pound LEO payload capacity NASA Delta, the 11,300-pound LEO payload capacity Atlas Centaur the first ICBM, and the all-solid propellant expendable 2000-pound LEO payload Conestoga rocket. Also considered is the man-rated fully reusable Phoenix vertical take-off and vertical-landing launch vehicle.

  11. High-density lipoprotein cholesterol as an independent risk factor in cardiovascular disease: assessing the data from Framingham to the Veterans Affairs High--Density Lipoprotein Intervention Trial.

    PubMed

    Boden, W E

    2000-12-21

    The Framingham Heart Study found that high-density lipoprotein cholesterol (HDL-C) was the most potent lipid predictor of coronary artery disease risk in men and women >49 years of age. The Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS), in which subjects were randomized to treatment with lovastatin or placebo, also reported a striking benefit of treatment, particularly in patients with HDL-C < or =35 mg/dL at baseline. Treatment with lovastatin was associated with a remarkable 45% reduction in events for this group. The Veterans Affairs HDL Intervention Trial (VA-HIT) randomized subjects to gemfibrozil or placebo. A high proportion of enrolled subjects with low HDL-C also had characteristics of the dysmetabolic syndrome. HDL-C likewise increased by 6% on treatment, total cholesterol was reduced by 4% and triglycerides by 31%. There was no change in low-density lipoprotein cholesterol (LDL-C) levels. These changes in lipid were associated with a cumulative 22% reduction in the trial primary endpoint of all-cause mortality and nonfatal myocardial infarction (MI). Additionally, significant reductions in secondary endpoints including death from coronary artery disease, nonfatal MI, stroke, transient ischemic attack, and carotid endarterectomy were associated with the increase in HDL-C. In VA-HIT, for every 1% increase in HDL-C, there was a 3% reduction in death or MI, a therapeutic benefit that eclipses the benefit associated with LDL-C reduction. PMID:11374850

  12. High density of (pseudo) periodic twin-grain boundaries in molecular beam epitaxy-grown van der Waals heterostructure: MoTe2/MoS2

    NASA Astrophysics Data System (ADS)

    Diaz, Horacio Coy; Ma, Yujing; Chaghi, Redhouane; Batzill, Matthias

    2016-05-01

    Growth of transition metal dichalcogenide heterostructures by molecular beam epitaxy (MBE) promises synthesis of artificial van der Waals materials with controllable layer compositions and separations. Here, we show that MBE growth of 2H-MoTe2 monolayers on MoS2 substrates results in a high density of mirror-twins within the films. The grain boundaries are tellurium deficient, suggesting that Te-deficiency during growth causes their formation. Scanning tunneling microscopy and spectroscopy reveal that the grain boundaries arrange in a pseudo periodic "wagon wheel" pattern with only ˜2.6 nm repetition length. Defect states from these domain boundaries fill the band gap and thus give the monolayer an almost metallic property. The band gap states pin the Fermi-level in MoTe2 and thus determine the band-alignment in the MoTe2/MoS2 interface.

  13. 21 CFR 573.780 - Polyethylene.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Polyethylene. 573.780 Section 573.780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.780 Polyethylene. (a)...

  14. Screening of upregulated genes induced by high density in the vetch aphid Megoura crassicauda.

    PubMed

    Ishikawa, Asano; Ishikawa, Yuki; Okada, Yasukazu; Miyazaki, Satoshi; Miyakawa, Hitoshi; Koshikawa, Shigeyuki; Brisson, Jennifer A; Miura, Toru

    2012-03-01

    Aphids exhibit several polyphenisms in which discontinuous, alternative phenotypes are produced depending on environmental conditions. One representative example is the wing polyphenism, where winged and wingless females are produced through parthenogenesis. Previous work has shown that, in some aphid species, the density condition sensed by the mother aphid determines the developmental fate of embryos in her ovary, with high densities leading to winged progeny and low densities to wingless progeny. However, little is known about the molecular and physiological mechanisms underlying the wing polyphenism. To identify genes involved in the wing-morph determination in the vetch aphid, Megoura crassicauda, we compared maternal and embryonic transcripts between high- and low-density conditions using differential display, followed by quantitative real-time PCR (qRT-PCR). Under the high-density condition, two genes (Uba1 and Naca) were found to be upregulated in maternal tissues without ovaries, while one gene (ClpP) was upregulated in ovaries containing embryos. Uba1 and Naca encode factors that function in protein modification or transcriptional/translational regulation, respectively. In addition to differential display, candidate gene approaches focusing on morphogenetic and endocrine genes, i.e., wg, dpp, ap, hh, InR, IRS, Foxo, EcR, and USP, were also carried out. We found that wg was upregulated in maternal tissues under the high-density condition. The identified genes from both approaches are candidates for further study of their involvement in the transduction of density signals in mother aphids and/or the initial process of wing differentiation in embryos. PMID:22514053

  15. Characterizing North Texas Seismicity with a High Density Network of Exploration Seismic Reflection Recorders

    NASA Astrophysics Data System (ADS)

    Hayward, C.; Barklage, M.; Hollis, D.; DeShon, H. R.; Magnani, M. B.

    2014-12-01

    A series of low magnitude earthquakes in North Texas near Azle, Texas began 5-Nov 2013 and continues to the present. By 3-Jan 2014, hypocenters based on a temporary local network were sufficiently well defined to plan an experiment using a dense network near the epicenters. On 25-Feb 2014, NodalSeismic in cooperation with Southern Methodist University, installed and operated 130 vertical 10 Hz recorders distributed along three lines within a few km of the epicenters and collected 10 days of continuous seismic recording at 500 samples/second. Data was converted from SEGD to standard earthquake seismological formats (SEED) for processing.During the time of the high density recording, relatively few events in the Azle area were detected by the 12 station local network; however, correlation processing on the dense network detected over 100 events. In addition regional events from local quarries as well as a teleseism were well recorded. One of the 10Hz recorders was within 50m of a 1 Hz vertical seismometer, providing the ability to evaluate the utility of the high frequency geophones for recording broader band signals. By comparing catalogs from the local network with detection lists from the high density network, the detection threshold for the augmented network is determined. Delta time offsets for the teleseismic signal may be used to determine relative station corrections (static offsets) prior to fitting classical hyperbola to a velocity model and to estimate epicenters. Comparison between dense network location results and results using standard techniques on the 12 station local network provides an assessment of the utility of this high density technique to quickly evaluate areas where induced seismicity is suspected. Finally, the method provides an opportunity to compare background noise levels between the rapidly installed low cost exploration systems and the more carefully deployed local network.

  16. The Application of High Density Electronic Packaging for Spacecraft Cost and Mass Reduction

    NASA Astrophysics Data System (ADS)

    Lowry, Lynn E.; Prokop, Jon S.; Sandborn, Peter; Evans, Kristan

    1995-01-01

    It has become clear over the past few years that packaging of spacecraft electronic systems must be improved. Not only have the weight and volume taken up by conventional packaging and interconnect systems become excessive, but active devices have advanced to the point where system performance is often limited by the packaging. Since electronic systems account for up to 30% of the size and weight budgets of a spacecraft, the utilization of high density electronic packaging will be a very important path to overall spacecraft miniaturization. In the late 1970's high density interconnection technologies were being introduced into mainframe computer applications. Subsequently, these technologies have been applied to avionics, telecommunication, biomedical and automotive systems. In each application the driving forces behind the adoption of these technologies were; improved electrical performance, miniaturization, reduced power consumption, increased reliability and reduced manufacturing costs. The application of these technologies to planetary missions could provide significant benefits by way of reduced cost and design time if commercial technology and best commercial manufacturing practices are accepted. A mixed signal telecommunication function has been used as an example to illustrate the potential mass, volume and power reduction achievable with the implementation of high density packaging technologies. The tradeoff analysis which was performed demonstrated that packaging technology selection is application specific, and system level impact must be considered early on in the design process. The results of this study which compare size, performance, cost, risk and system level impact are given. Finally, the technical and cultural obstacles which have inhibited the implementation of these technologies is discussed. Specifically, the issues of space qualified hardware and technology availability is addressed. Space qualification is perceived by industry as being the

  17. Dst prediction for a period of high-density plasmas in magnetic clouds

    NASA Astrophysics Data System (ADS)

    Adachi, H.; Sakurai, T.

    We examine geomagnetic effects for high-density plasmas in magnetic clouds and their relationship to solar sources. It is well known that Bz component of interplanetary magnetic field plays an important role for estimation of Dst from solar wind parameters (Burton et al.1975). However, magnetic clouds frequently carry high-density plasmas, which are interpreted as the remnants of filament. In order to clarify their geomagnetic effects, we try to estimate Dst by adopting different methods introducing effects of solar wind parameters. In our estimation the most important point is laid on the sense of Dst variation rather than its magnitude. The most suitable estimation is obtained by setting up a threshold for plasma density, in which for a case of plasma density greater than 20 /cc the Fenrich and Luhmann (1998)'s formula should be used, while in the other cases the Burton's formula are adopted. In both estimations the O'Brien and McPherron (2000)'s ring current decay time is employed. Furthermore, we examine the solar origin corresponding to the magnetic clouds and then compared characteristic signatures of the magnetic cloud with those observed on the solar surface. As a result, we confirm that the magnetic structure of interplanetary flux rope is in good agreement with the structures of the magnetic neutral line near disappearing filaments and heliospheric current sheet (HCS). On the basis of these studies, we suggest that for the geomagnetic disturbance forecast, the effect of high-density plasmas carried with magnetic clouds should be taken into account of as well as that of interplanetary magnetic field.

  18. Folded functional lipid-poor apolipoprotein A-I obtained by heating of high-density lipoproteins: relevance to high-density lipoprotein biogenesis.

    PubMed

    Jayaraman, Shobini; Cavigiolio, Giorgio; Gursky, Olga

    2012-03-15

    HDL (high-density lipoproteins) remove cell cholesterol and protect from atherosclerosis. The major HDL protein is apoA-I (apolipoprotein A-I). Most plasma apoA-I circulates in lipoproteins, yet ~5% forms monomeric lipid-poor/free species. This metabolically active species is a primary cholesterol acceptor and is central to HDL biogenesis. Structural properties of lipid-poor apoA-I are unclear due to difficulties in isolating this transient species. We used thermal denaturation of human HDL to produce lipid-poor apoA-I. Analysis of the isolated lipid-poor fraction showed a protein/lipid weight ratio of 3:1, with apoA-I, PC (phosphatidylcholine) and CE (cholesterol ester) at approximate molar ratios of 1:8:1. Compared with lipid-free apoA-I, lipid-poor apoA-I showed slightly altered secondary structure and aromatic packing, reduced thermodynamic stability, lower self-associating propensity, increased adsorption to phospholipid surface and comparable ability to remodel phospholipids and form reconstituted HDL. Lipid-poor apoA-I can be formed by heating of either plasma or reconstituted HDL. We propose the first structural model of lipid-poor apoA-I which corroborates its distinct biophysical properties and postulates the lipid-induced ordering of the labile C-terminal region. In summary, HDL heating produces folded functional monomolecular lipid-poor apoA-I that is distinct from lipid-free apoA-I. Increased adsorption to phospholipid surface and reduced C-terminal disorder may help direct lipid-poor apoA-I towards HDL biogenesis. PMID:22150513

  19. The mantle of Mars - Some possible geological implications of its high density

    NASA Technical Reports Server (NTRS)

    Mcgetchin, T. R.; Smyth, J. R.

    1978-01-01

    The high density of the Martian mantle probably implies an iron-rich composition expressed by a higher concentration of FeO than that in the earth's mantle. Examination of high-pressure mineralogies suggests that the model Martian mantle has an oxide-garnet wehrlite phase assemblage. This mantle model would be likely to yield ultrabasic (ferrobasaltic) melts of very low viscosity. The prevalence of low-viscosity material is consistent with large eruption rate and copious lava flow on the planet. Furthermore, ferro-kimberlite volcanic ash may be an abundant constituent in the Martian soil, especially if there was much volatile material within the early accreting Mars.

  20. Rapid inactivation of Penicillium digitatum spores using high-density nonequilibrium atmospheric pressure plasma

    SciTech Connect

    Iseki, Sachiko; Hori, Masaru; Ohta, Takayuki; Aomatsu, Akiyoshi; Ito, Masafumi; Kano, Hiroyuki; Higashijima, Yasuhiro

    2010-04-12

    A promising, environmentally safe method for inactivating fungal spores of Penicillium digitatum, a difficult-to-inactivate food spoilage microorganism, was developed using a high-density nonequilibrium atmospheric pressure plasma (NEAPP). The NEAPP employing Ar gas had a high electron density on the order of 10{sup 15} cm{sup -3}. The spores were successfully and rapidly inactivated using the NEAPP, with a decimal reduction time in spores (D value) of 1.7 min. The contributions of ozone and UV radiation on the inactivation of the spores were evaluated and concluded to be not dominant, which was fundamentally different from the conventional sterilizations.

  1. Reliability of High I/O High Density CCGA Interconnect Electronic Packages under Extreme Thermal Environment

    NASA Technical Reports Server (NTRS)

    Ramesham, Rajeshuni

    2012-01-01

    This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non-destructive inspection tools were used to assess the reliability of high density CCGA packages for deep space extreme temperature missions. Ceramic column grid array (CCGA) packages have been increasing in use based on their advantages such as high interconnect density, very good thermal and electrical performances, compatibility with standard surface-mount packaging assembly processes, and so on. CCGA packages are used in space applications such as in logic and microprocessor functions, telecommunications, payload electronics, and flight avionics. As these packages tend to have less solder joint strain relief than leaded packages or more strain relief over lead-less chip carrier packages, the reliability of CCGA packages is very important for short-term and long-term deep space missions. We have employed high density CCGA 1152 and 1272 daisy chained electronic packages in this preliminary reliability study. Each package is divided into several daisy-chained sections. The physical dimensions of CCGA1152 package is 35 mm x 35 mm with a 34 x 34 array of columns with a 1 mm pitch. The dimension of the CCGA1272 package is 37.5 mm x 37.5 mm with a 36 x 36 array with a 1 mm pitch. The columns are made up of 80% Pb/20%Sn material. CCGA interconnect electronic package printed wiring polyimide boards have been assembled and inspected using non-destructive x-ray imaging techniques. The assembled CCGA boards were subjected to extreme temperature thermal atmospheric cycling to assess their reliability for future deep space missions. The resistance of daisy-chained interconnect sections were monitored continuously during thermal cycling. This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non

  2. Matrix sublimation method for the formation of high-density amorphous ice

    NASA Astrophysics Data System (ADS)

    Kouchi, A.; Hama, T.; Kimura, Y.; Hidaka, H.; Escribano, R.; Watanabe, N.

    2016-08-01

    A novel method for the formation of amorphous ice involving matrix sublimation has been developed. A CO-rich CO:H2O mixed ice was deposited at 8-10 K under ultra-high vacuum condition, which was then allowed to warm. After the sublimation of matrix CO at 35 K, amorphous ice remained. The amorphous ice formed exhibits a highly porous microscale texture; however, it also rather exhibits a density similar to that of high-density amorphous ice formed under high pressure. Furthermore, unlike conventional vapor-deposited amorphous ice, the amorphous ice is stable up to 140 K, where it transforms directly to cubic ice Ic.

  3. Stimulatory and possible antioxidant effects of High Density Green Photons (HDGP) on cellular systems

    PubMed Central

    Paslaru, L; Nastase, A; Stefan, L; Florea, R; Sorop, A; Ionescu, E; Popescu, I; Comorasan, S

    2014-01-01

    The interactions between the electromagnetic field and the biological systems were extensively investigated, with remarkable results and advanced technologies. Nevertheless, the visible domain of the spectrum has been rather neglected, since the classic physics did not allow electronic transitions induced by visible light. Recently, the interaction of light with the matter has generated a new scientific domain known in Physics as optical manipulation, with the new concepts of optical matter and optical force. This article presents the results of our work concerning in vitro effects of High Density Green Photons (HDGP) irradiation on cell cultures: stimulation of cell proliferation and migration and a possible antioxidant action. PMID:25713633

  4. High density packing and interconnections for hybrid microelectronics: new trends in materials development

    NASA Astrophysics Data System (ADS)

    Jakubowska, Małgorzata

    2008-01-01

    Electronic devices, components, circuits and microsystems continue to become smaller, lighter, faster and less expensive. The progress in hybrid microelectronics, especially in high density packaging and interconnections, is very much dependent on the achievements in developing new electronic materials. The paper presents the state of art of thick film materials as well as the new developments carried in Hybrid Mirocircuits and Microsystems Laboratory, which was established in 2006 by Warsaw University of Technology, Department of Electronics and Information Technology and Institute of Electronic Materials Technology.

  5. Magnetic structure of nickel nanowires after the high-density current pulse

    NASA Astrophysics Data System (ADS)

    Nurgazizov, N. I.; Bizyaev, D. A.; Bukharaev, A. A.

    2016-05-01

    Changes in the magnetic structure of nickel nanowires formed on a nonconductive surface after the high-density current pulse have been investigated using magnetic force microscopy and voltammetry. Based on the obtained experimental data and results of the computer simulation, it has been concluded that the main reason for the change in the magnetic structure is the heating of the nanowire by a current pulse. It has been shown that, during the subsequent cooling, the newly formed magnetic structure is pinned by surface roughnesses of the relief of the nanowire under investigation.

  6. High-Density Livestock Production and Molecularly Characterized MRSA Infections in Pennsylvania

    PubMed Central

    Casey, Joan A.; Shopsin, Bo; Cosgrove, Sara E.; Nachman, Keeve E.; Curriero, Frank C.; Rose, Hannah R.

    2014-01-01

    Background: European studies suggest that living near high-density livestock production increases the risk of sequence type (ST) 398 methicillin-resistant Staphylococcus aureus (MRSA) colonization. To our knowledge, no studies have evaluated associations between livestock production and human infection by other strain types. Objectives: We evaluated associations between MRSA molecular subgroups and high-density livestock production. Methods: We conducted a yearlong 2012 prospective study on a stratified random sample of patients with culture-confirmed MRSA infection; we oversampled patients from the Geisinger Health System with exposure to high-density livestock production in Pennsylvania. Isolates were characterized using S. aureus protein A (spa) typing and detection of Panton-Valentine leukocidin (PVL) and scn genes. We compared patients with one of two specific MRSA strains with patients with all other strains of MRSA isolates, using logistic regression that accounted for the sampling design, for two different exposure models: one based on the location of the animals (livestock model) and the other on crop field application of manure (crop field model). Results: Of 196 MRSA isolates, we identified 30 spa types, 47 PVL-negative and 15 scn-negative isolates, and no ST398 MRSA. Compared with quartiles 1–3 combined, the highest quartiles of swine livestock and dairy/veal crop field exposures were positively associated with community-onset-PVL-negative MRSA (CO-PVL-negative MRSA vs. all other MRSA), with adjusted odds ratios of 4.24 (95% CI: 1.60, 11.25) and 4.88 (95% CI: 1.40, 17.00), respectively. The association with CO-PVL-negative MRSA infection increased across quartiles of dairy/veal livestock exposure (trend p = 0.05). Conclusions: Our findings suggest that other MRSA strains, beyond ST398, may be involved in livestock-associated MRSA infection in the United States. Citation: Casey JA, Shopsin B, Cosgrove SE, Nachman KE, Curriero FC, Rose HR, Schwartz BS

  7. High-density display of protein ligands on self-assembled capsules via noncovalent fluorous interactions.

    PubMed

    Harano, Koji; Yamada, Junya; Mizuno, Shinichiro; Nakamura, Eiichi

    2015-01-01

    Ligand display on self-assembled nanostructures is an important tool in generating bioactive materials. Here, we demonstrate the display of sugar and biotin molecules on sub-100 nm-sized capsules with a high surface coverage, which was achieved by the use of noncovalent fluorous interactions between a fluorous-tagged ligand molecule and a fullerene vesicle covered with fluorous chains. Even after the high-density ligand display and protein binding, the vesicle stably maintains its spherical structure because the fluorous binding of the sugar does not affect the structural integrity of the vesicle that originates from strong fullerene-fullerene interactions. PMID:25404018

  8. High-Density Holographic Data Storage Using Three-Dimensional Shift Multiplexing with Spherical Reference Wave

    NASA Astrophysics Data System (ADS)

    Yoshida, Shuhei; Kurata, Hiroyuki; Ozawa, Shohei; Okubo, Kaito; Horiuchi, Shuma; Ushiyama, Zenta; Yamamoto, Manabu; Koga, Shogo; Tanaka, Asato

    2013-09-01

    In this study, we propose a three-dimensional shift multiplexing technique using a spherical reference wave. By utilizing a spherical reference wave, multiplex recording is enabled in this system by simply displacing the recording medium. The utilization of a spherical reference wave makes it possible to realize three-dimensional multiplexing, which uses parallel directions of the medium surface and thickness direction. It is also expected that this approach will improve the recording density as compared with the conventional multiplex technique. We report the numerical and experimental evaluation results of our high-density recording and reproduction system based on this principle.

  9. Synthetic high-density lipoprotein-like nanoparticles for cancer therapy

    PubMed Central

    Foit, Linda; Giles, Francis J.; Gordon, Leo I.; Thaxton, C. Shad

    2015-01-01

    Summary High-density lipoproteins (HDLs) are a diverse group of natural nanoparticles that are most well-known for their role in cholesterol transport. However, HDLs have diverse functions that provide significant opportunities for cancer therapy. Presented is a focused review of the ways that synthetic versions of HDL have been used as targeted therapies for cancer, and as vehicles for the delivery of diverse therapeutic cargo to cancer cells. As such, synthetic HDLs are likely to play a central role in the development of next generation cancer therapies. PMID:25487833

  10. Light scattering from metal sol labels on high-density DNA probe arrays

    NASA Astrophysics Data System (ADS)

    Trulson, Mark O.; Walton, Ian D.; Suseno, Audrey D.; Matsuzaki, Hajime; Stern, David

    1998-04-01

    We have been exploring the use of light scattering as a means to detect the binding of nucleic acids to high density DNA probe arrays. Initial work has concentrated on the use of 100 nanometer gold particles conjugated to monoclonal antibodies. A probe array scanner that utilizes an arc lamp source and a `photocopier grade' linear CCD detector has been developed. The optical configuration of the scanner maximizes dynamic range and minimizes optical backgrounds. Initial development of light scattering detection for the p53 cancer gene application shows that functional performance may be obtained that is essentially equivalent to existing fluorescence detection methodology.

  11. Co-isolation of extracellular vesicles and high-density lipoproteins using density gradient ultracentrifugation

    PubMed Central

    Yuana, Yuana; Levels, Johannes; Grootemaat, Anita; Sturk, Auguste; Nieuwland, Rienk

    2014-01-01

    Extracellular vesicles (EVs) facilitate intercellular communication by carrying bioactive molecules such as proteins, messenger RNA, and micro (mi)RNAs. Recently, high-density lipoproteins (HDL) isolated from human plasma were also reported to transport miRNA to other cells. HDL, when isolated from human plasma, ranges in density between 1.063 and 1.21 g/mL, which grossly overlap with the reported density of EVs. Consequently, HDL and EV will be co-isolated when using density gradient ultracentrifugation. Thus, more stringent isolation/separation procedures of EV and HDL are essential to know their relative contribution to the pool of circulating bioactive molecules. PMID:25018865

  12. Efficient light coupling for optically excited high-density metallic nanotip arrays

    PubMed Central

    Mustonen, Anna; Beaud, Paul; Kirk, Eugenie; Feurer, Thomas; Tsujino, Soichiro

    2012-01-01

    Ultrafast electron pulses can be produced from sharp metallic tips illuminated by femtosecond near infrared laser pulses. Use of an array of metallic nanotips for high charge bunch generation and accelerator applications is also feasible but the small fraction of the emitter tip area limits the quantum efficiency. We therefore propose a submicron-pitch, high-density nanotip array device with a gate electrode, that can support surface-plasmon polaritons. From a theoretical analysis for a device with an asymmetric emitter position, a factor ~30 increased array quantum efficiency is demonstrated. PMID:23209875

  13. Feedforward, high density, programmable read only neural network based memory system

    NASA Technical Reports Server (NTRS)

    Daud, Taher; Moopenn, Alex; Lamb, James; Thakoor, Anil; Khanna, Satish

    1988-01-01

    Neural network-inspired, nonvolatile, programmable associative memory using thin-film technology is demonstrated. The details of the architecture, which uses programmable resistive connection matrices in synaptic arrays and current summing and thresholding amplifiers as neurons, are described. Several synapse configurations for a high-density array of a binary connection matrix are also described. Test circuits are evaluated for operational feasibility and to demonstrate the speed of the read operation. The results are discussed to highlight the potential for a read data rate exceeding 10 megabits/sec.

  14. Optimization towards high density quantum dots for intermediate band solar cells grown by molecular beam epitaxy

    SciTech Connect

    Zhou, D.; Sharma, G.; Fimland, B. O.; Thomassen, S. F.; Reenaas, T. W.

    2010-02-08

    We report high density quantum dots (QDs) formation with optimized growth temperature and V/III ratio. At lower growth temperature, QD density is increased, due to smaller surface migration length of In adatoms. With higher V/III, the QD density is higher but it results in large clusters formation and decreases the QD uniformity. The QD solar cell was fabricated and examined. An extended spectral response in contrast to the GaAs reference cell was presented but the external quantum efficiency at energies higher than GaAs band gap is reduced, resulting from the degradation for the emitter above the strained QD layers.

  15. High density nitrogen-vacancy sensing surface created via He+ ion implantation of 12C diamond

    NASA Astrophysics Data System (ADS)

    Kleinsasser, Ed E.; Stanfield, Matthew M.; Banks, Jannel K. Q.; Zhu, Zhouyang; Li, Wen-Di; Acosta, Victor M.; Watanabe, Hideyuki; Itoh, Kohei M.; Fu, Kai-Mei C.

    2016-05-01

    We present a promising method for creating high-density ensembles of nitrogen-vacancy centers with narrow spin-resonances for high-sensitivity magnetic imaging. Practically, narrow spin-resonance linewidths substantially reduce the optical and RF power requirements for ensemble-based sensing. The method combines isotope purified diamond growth, in situ nitrogen doping, and helium ion implantation to realize a 100 nm-thick sensing surface. The obtained 1017 cm-3 nitrogen-vacancy density is only a factor of 10 less than the highest densities reported to date, with an observed 200 kHz spin resonance linewidth over 10 times narrower.

  16. Pesticide occurrence in groundwater in areas of high-density row crop production in Alabama, 2009

    USGS Publications Warehouse

    Moreland, Richard S.

    2011-01-01

    High-density row crop production occurs in three areas of Alabama that are underlain by productive aquifers, northern Alabama, southeastern Alabama, and Baldwin County in southwestern Alabama. The U.S. Geological Survey collected five groundwater samples from each of these three areas during 2009 for analysis of selected pesticides. Results of these analyses showed detections for 37 of 152 analytes. The three most frequently detected compounds were atrazine, 2-Chloro-4-isopropylamino-6-amino-triazine (CIAT), and metolachlor. The highest concentration for any analyte was 4.08 micrograms per liter for metolachlor.

  17. Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk

    NASA Astrophysics Data System (ADS)

    Chen, Ruey Shan; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab; Salleh, Mohd Nazry

    2014-09-01

    Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50-90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young's modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

  18. Utilization of star-shaped polymer architecture in the creation of high-density polymer brush coatings for the prevention of platelet and bacteria adhesion

    PubMed Central

    Totani, Masayasu; Terada, Kayo; Terashima, Takaya; Kim, Ill Yong; Ohtsuki, Chikara; Xi, Chuanwu; Tanihara, Masao

    2014-01-01

    We demonstrate utilization of star-shaped polymers as high-density polymer brush coatings and their effectiveness to inhibit the adhesion of platelets and bacteria. Star polymers consisting of poly(2-hydroxyethyl methacrylate) (PHEMA) and/or poly(methyl methacrylate) (PMMA), were synthesized using living radical polymerization with a ruthenium catalyst. The polymer coatings were prepared by simple drop casting of the polymer solution onto poly(ethylene terephthalate) (PET) surfaces and then dried. Among the star polymers prepared in this study, the PHEMA star polymer (star-PHEMA) and the PHEMA/PMMA (mol. ratio of 71/29) heteroarm star polymer (star-H71M29) coatings showed the highest percentage of inhibition against platelet adhesion (78–88% relative to noncoated PET surface) and Escherichia coli (94–97%). These coatings also showed anti-adhesion activity against platelets after incubation in Dulbecco's phosphate buffered saline or surfactant solution for 7 days. In addition, the PMMA component of the star polymers increased the scratch resistance of the coating. These results indicate that the star-polymer architecture provides high polymer chain density on PET surfaces to prevent adhesion of platelets and bacteria, as well as coating stability and physical durability to prevent exposure of bare PET surfaces. The star polymers provide a simple and effective approach to preparing anti-adhesion polymer coatings on biomedical materials against the adhesion of platelets and bacteria. PMID:25485105

  19. Utilization of star-shaped polymer architecture in the creation of high-density polymer brush coatings for the prevention of platelet and bacteria adhesion.

    PubMed

    Totani, Masayasu; Ando, Tsuyoshi; Terada, Kayo; Terashima, Takaya; Kim, Ill Yong; Ohtsuki, Chikara; Xi, Chuanwu; Kuroda, Kenichi; Tanihara, Masao

    2014-09-01

    We demonstrate utilization of star-shaped polymers as high-density polymer brush coatings and their effectiveness to inhibit the adhesion of platelets and bacteria. Star polymers consisting of poly(2-hydroxyethyl methacrylate) (PHEMA) and/or poly(methyl methacrylate) (PMMA), were synthesized using living radical polymerization with a ruthenium catalyst. The polymer coatings were prepared by simple drop casting of the polymer solution onto poly(ethylene terephthalate) (PET) surfaces and then dried. Among the star polymers prepared in this study, the PHEMA star polymer (star-PHEMA) and the PHEMA/PMMA (mol. ratio of 71/29) heteroarm star polymer (star-H71M29) coatings showed the highest percentage of inhibition against platelet adhesion (78-88% relative to noncoated PET surface) and Escherichia coli (94-97%). These coatings also showed anti-adhesion activity against platelets after incubation in Dulbecco's phosphate buffered saline or surfactant solution for 7 days. In addition, the PMMA component of the star polymers increased the scratch resistance of the coating. These results indicate that the star-polymer architecture provides high polymer chain density on PET surfaces to prevent adhesion of platelets and bacteria, as well as coating stability and physical durability to prevent exposure of bare PET surfaces. The star polymers provide a simple and effective approach to preparing anti-adhesion polymer coatings on biomedical materials against the adhesion of platelets and bacteria. PMID:25485105

  20. High-density electroencephalography as an innovative tool to explore sleep physiology and sleep related disorders.

    PubMed

    Pisarenco, I; Caporro, M; Prosperetti, C; Manconi, M

    2014-01-01

    High density EEG represents a promising tool to achieve new insights regarding sleep physiology and pathology. It combines the advantages of an EEG technique as an optimal temporal resolution with the spatial resolution of the neuroimaging. So far its application in sleep research contributed to better characterize some of the peculiar microstructural figures of sleep such as spindles and K-complexes, and to understand the fundamental relationships between sleep and synaptic plasticity, learning and consciousness. Its application is not limited to neurophysiology, being recently also applied to study some sleep related psychiatric and neurological disorders such as depression, schizophrenia, attention-deficit hyperactivity disorder, and stroke. adding some interesting new pieces in the pathophysiological puzzle of these diseases. Due to its non-invasive, repetitive and reliable tempo-spatial resolution it is reasonable that the field of application of this tool will be soon enlarged to other areas of neuroscience. The present review aims to offer a complete overview regarding the use of high density EEG over the last decade in sleep research and sleep medicine, including its possible future perspective. PMID:24412343

  1. Effects of high density on spacing behaviour and reproduction in Akodon azarae: A fencing experiment

    NASA Astrophysics Data System (ADS)

    Ávila, Belén; Bonatto, Florencia; Priotto, José; Steinmann, Andrea R.

    2016-01-01

    We studied the short term spacing behavioural responses of Pampean grassland mouse (Akodon azarae) with regard to population density in four 0.25 ha enclosures (two control and two experimental) in the 2011 breeding season. Based on the hypothesis that A. azarae breeding females exhibit spacing behaviour, and breeding males show a fusion spatial response, we tested the following predictions: (1) home range size and intrasexual overlap degree of females are independent of population density values; (2) at high population density, home range size of males decreases and the intrasexual home range overlap degree increases. To determine if female reproductive success decreases at high population density, we analyzed pregnancy rate, size and weight of litters, and period until fecundation in both low and high enclosure population density. We found that both males and females varied their home range size in relation to population density. Although male home ranges were always bigger than those of females in populations with high density, home range sizes of both sexes decreased. Females kept exclusive home ranges independent of density values meanwhile males decreased home range overlap in high breeding density populations. Although females produced litters of similar size in both treatments, weight of litter, pregnant rate and period until fecundation varied in relation to population density. Our results did not support the hypothesis that at high density females of A. azarae exhibit spacing behaviour neither that males exhibit a fusion spatial response.

  2. High-energy side-peak emission of exciton-polariton condensates in high density regime

    PubMed Central

    Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

    2016-01-01

    In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates–sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity–have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics. PMID:27193700

  3. High-energy side-peak emission of exciton-polariton condensates in high density regime

    NASA Astrophysics Data System (ADS)

    Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

    2016-05-01

    In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates–sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity–have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics.

  4. High-energy side-peak emission of exciton-polariton condensates in high density regime.

    PubMed

    Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

    2016-01-01

    In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates-sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity-have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics. PMID:27193700

  5. Anisotropic viscoelastic-viscoplastic continuum model for high-density cellulose-based materials

    NASA Astrophysics Data System (ADS)

    Tjahjanto, D. D.; Girlanda, O.; Östlund, S.

    2015-11-01

    A continuum material model is developed for simulating the mechanical response of high-density cellulose-based materials subjected to stationary and transient loading. The model is formulated in an infinitesimal strain framework, where the total strain is decomposed into elastic and plastic parts. The model adopts a standard linear viscoelastic solid model expressed in terms of Boltzmann hereditary integral form, which is coupled to a rate-dependent viscoplastic formulation to describe the irreversible plastic part of the overall strain. An anisotropic hardening law with a kinematic effect is particularly adopted in order to capture the complex stress-strain hysteresis typically observed in polymeric materials. In addition, the present model accounts for the effects of material densification associated with through-thickness compression, which are captured using an exponential law typically applied in the continuum description of elasticity in porous media. Material parameters used in the present model are calibrated to the experimental data for high-density (press)boards. The experimental characterization procedures as well as the calibration of the parameters are highlighted. The results of the model simulations are systematically analyzed and validated against the corresponding experimental data. The comparisons show that the predictions of the present model are in very good agreement with the experimental observations for both stationary and transient load cases.

  6. An Ultra-High-Density, Transcript-Based, Genetic Map of Lettuce

    PubMed Central

    Truco, Maria José; Ashrafi, Hamid; Kozik, Alexander; van Leeuwen, Hans; Bowers, John; Wo, Sebastian Reyes Chin; Stoffel, Kevin; Xu, Huaqin; Hill, Theresa; Van Deynze, Allen; Michelmore, Richard W.

    2013-01-01

    We have generated an ultra-high-density genetic map for lettuce, an economically important member of the Compositae, consisting of 12,842 unigenes (13,943 markers) mapped in 3696 genetic bins distributed over nine chromosomal linkage groups. Genomic DNA was hybridized to a custom Affymetrix oligonucleotide array containing 6.4 million features representing 35,628 unigenes of Lactuca spp. Segregation of single-position polymorphisms was analyzed using 213 F7:8 recombinant inbred lines that had been generated by crossing cultivated Lactuca sativa cv. Salinas and L. serriola acc. US96UC23, the wild progenitor species of L. sativa. The high level of replication of each allele in the recombinant inbred lines was exploited to identify single-position polymorphisms that were assigned to parental haplotypes. Marker information has been made available using GBrowse to facilitate access to the map. This map has been anchored to the previously published integrated map of lettuce providing candidate genes for multiple phenotypes. The high density of markers achieved in this ultradense map allowed syntenic studies between lettuce and Vitis vinifera as well as other plant species. PMID:23550116

  7. High-density biosynthetic fuels: the intersection of heterogeneous catalysis and metabolic engineering.

    PubMed

    Harvey, Benjamin G; Meylemans, Heather A; Gough, Raina V; Quintana, Roxanne L; Garrison, Michael D; Bruno, Thomas J

    2014-05-28

    Biosynthetic valencene, premnaspirodiene, and natural caryophyllene were hydrogenated and evaluated as high performance fuels. The parent sesquiterpenes were then isomerized to complex mixtures of hydrocarbons with the heterogeneous acid catalyst Nafion SAC-13. High density fuels with net heats of combustion ranging from 133-141 000 Btu gal(-1), or up to 13% higher than commercial jet fuel could be generated by this approach. The products of caryophyllene isomerization were primarily tricyclic hydrocarbons which after hydrogenation increased the fuel density by 6%. The isomerization of valencene and premnaspirodiene also generated a variety of sesquiterpenes, but in both cases the dominant product was δ-selinene. Ab initio calculations were conducted to determine the total electronic energies for the reactants and products. In all cases the results were in excellent agreement with the experimental distribution of isomers. The cetane numbers for the sesquiterpane fuels ranged from 20-32 and were highly dependent on the isomer distribution. Specific distillation cuts may have the potential to act as high density diesel fuels, while use of these hydrocarbons as additives to jet fuel will increase the range and/or time of flight of aircraft. In addition to the ability to generate high performance renewable fuels, the powerful combination of metabolic engineering and heterogeneous catalysis will allow for the preparation of a variety of sesquiterpenes with potential for pharmaceutical, flavor, and fragrance applications. PMID:24724156

  8. Cryogenic THD and DT layer implosions with high density carbon ablators in near-vacuum hohlraums

    DOE PAGESBeta

    Meezan, N. B.; Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; et al

    2015-06-02

    High Density Carbon (HDC or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a DT layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a THD layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightlymore » oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 x 10¹⁵ neutrons, 40% of the 1D simulated yield.« less

  9. Cryogenic THD and DT layer implosions with high density carbon ablators in near-vacuum hohlraums

    SciTech Connect

    Meezan, N. B.; Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; Milovich, J. L.; Pak, A. E.; Ross, J. S.; Thomas, C. A.; Benedetti, L. R.; Bradley, D. K.; Celliers, P. M.; Clark, D. S.; Field, J. E.; Haan, S. W.; Izumi, N.; Kyrala, G. A.; Moody, J. D.; Patel, P. K.; Ralph, J. E.; Rygg, J. R.; Sepke, S. M.; Spears, B. K.; Tommasini, R.; Town, R. P. J.; Biener, J.; Bionta, R. M.; Bond, E. J.; Caggiano, J. A.; Eckart, M. J.; Gatu Johnson, M.; Grim, G. P.; Hamza, A. V.; Hartouni, E. P.; Hatarik, R.; Hoover, D. E.; Kilkenny, J. D.; Kozioziemski, B. J.; Kroll, J. J.; McNaney, J. M.; Nikroo, A.; Sayre, D. B.; Stadermann, M.; Wild, C.; Yoxall, B. E.; Landen, O. L.; Hsing, W. W.; Edwards, M. J.

    2015-06-02

    High Density Carbon (HDC or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a DT layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a THD layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 x 10¹⁵ neutrons, 40% of the 1D simulated yield.

  10. Investigations on the transport and metabolism of high density lipoprotein cholesteryl esters in African green monkeys

    SciTech Connect

    Sorci-Thomas, M.G.

    1984-01-01

    The metabolic fate of circulating high density lipoprotein cholesteryl esters was studied in African green monkeys to determine the significance of the lipid transfer reaction on the catabolism of lipoprotein cholesteryl esters. A method of doubly labeling both moieties of lipoprotein cholesteryl esters with (/sup 3/He)cholesteryl oleate and cholesteryl (/sup 14/C)oleate was developed for the purpose of studying plasma cholesteryl ester metabolism in vivo. In these studies the total plasma (/sup 3/He)cholesterol turnover resulted in production rates, which ranged from 10-17 mg/kg day, similar to previously reported values in African green monkeys and in normal lipoproteinemic humans. In contrast to the production rates calculated from the decay of plasma /sup 3/He-radioactivity, the production rates calculated from lipoproteins labeled with cholesteryl (/sup 14/C)oleate were approximately 2-3 times greater. In addition to these studies, a plasma cholesteryl ester transacylation activity was demonstrated in vitro when HDL containing doubly labeled cholesteryl esters were incubated with fresh plasma. These results demonstrated that high density lipoprotein cholesteryl esters undergo transacylation in vitro, resulting in release and reesterification of free (/sup 3/H)cholesterol.

  11. Exploration of high-density protein microarrays for antibody validation and autoimmunity profiling.

    PubMed

    Sjöberg, Ronald; Mattsson, Cecilia; Andersson, Eni; Hellström, Cecilia; Uhlen, Mathias; Schwenk, Jochen M; Ayoglu, Burcu; Nilsson, Peter

    2016-09-25

    High-density protein microarrays of recombinant human protein fragments, representing 12,412 unique Ensembl Gene IDs, have here been produced and explored. These protein microarrays were used to analyse antibody off-target interactions, as well as for profiling the human autoantibody repertoire in plasma against the antigens represented by the protein fragments. Affinity-purified polyclonal antibodies produced within the Human Protein Atlas (HPA) were analysed on microarrays of three different sizes, ranging from 384 antigens to 21,120 antigens, for evaluation of the antibody validation criteria in the HPA. Plasma samples from secondary progressive multiple sclerosis patients were also screened in order to explore the feasibility of these arrays for broad-scale profiling of autoantibody reactivity. Furthermore, analysis on these near proteome-wide microarrays was complemented with analysis on HuProt™ Human Proteome protein microarrays. The HPA recombinant protein microarray with 21,120 antigens and the HuProt™ Human Proteome protein microarray are currently the largest protein microarray platforms available to date. The results on these arrays show that the Human Protein Atlas antibodies have few off-target interactions if the antibody validation criteria are kept stringent and demonstrate that the HPA-produced high-density recombinant protein fragment microarrays allow for a high-throughput analysis of plasma for identification of possible autoantibody targets in the context of various autoimmune conditions. PMID:26417875

  12. Single step reconstitution of multifunctional high-density lipoprotein-derived nanomaterials using microfluidics.

    PubMed

    Kim, YongTae; Fay, Francois; Cormode, David P; Sanchez-Gaytan, Brenda L; Tang, Jun; Hennessy, Elizabeth J; Ma, Mingming; Moore, Kathryn; Farokhzad, Omid C; Fisher, Edward Allen; Mulder, Willem J M; Langer, Robert; Fayad, Zahi A

    2013-11-26

    High-density lipoprotein (HDL) is a natural nanoparticle that transports peripheral cholesterol to the liver. Reconstituted high-density lipoprotein (rHDL) exhibits antiatherothrombotic properties and is being considered as a natural treatment for cardiovascular diseases. Furthermore, HDL nanoparticle platforms have been created for targeted delivery of therapeutic and diagnostic agents. The current methods for HDL reconstitution involve lengthy procedures that are challenging to scale up. A central need in the synthesis of rHDL, and multifunctional nanomaterials in general, is to establish large-scale production of reproducible and homogeneous batches in a simple and efficient fashion. Here, we present a large-scale microfluidics-based manufacturing method for single-step synthesis of HDL-mimicking nanomaterials (μHDL). μHDL is shown to have the same properties (e.g., size, morphology, bioactivity) as conventionally reconstituted HDL and native HDL. In addition, we were able to incorporate simvastatin (a hydrophobic drug) into μHDL, as well as gold, iron oxide, quantum dot nanocrystals or fluorophores to enable its detection by computed tomography (CT), magnetic resonance imaging (MRI), or fluorescence microscopy, respectively. Our approach may contribute to effective development and optimization of lipoprotein-based nanomaterials for medical imaging and drug delivery. PMID:24079940

  13. High-density linkage mapping revealed suppression of recombination at the sex determination locus in papaya.

    PubMed Central

    Ma, Hao; Moore, Paul H; Liu, Zhiyong; Kim, Minna S; Yu, Qingyi; Fitch, Maureen M M; Sekioka, Terry; Paterson, Andrew H; Ming, Ray

    2004-01-01

    A high-density genetic map of papaya (Carica papaya L.) was constructed using 54 F(2) plants derived from cultivars Kapoho and SunUp with 1501 markers, including 1498 amplified fragment length polymorphism (AFLP) markers, the papaya ringspot virus coat protein marker, morphological sex type, and fruit flesh color. These markers were mapped into 12 linkage groups at a LOD score of 5.0 and recombination frequency of 0.25. The 12 major linkage groups covered a total length of 3294.2 cM, with an average distance of 2.2 cM between adjacent markers. This map revealed severe suppression of recombination around the sex determination locus with a total of 225 markers cosegregating with sex types. The cytosine bases were highly methylated in this region on the basis of the distribution of methylation-sensitive and -insensitive markers. This high-density genetic map is essential for cloning of specific genes of interest such as the sex determination gene and for the integration of genetic and physical maps of papaya. PMID:15020433

  14. C60-Fullerene Hyper-Velocity High-Density Plasma Jets for MIF and Disruption Mitigation

    NASA Astrophysics Data System (ADS)

    Bogatu, I. N.; Galkin, S. A.; Kim, J. S.

    2009-06-01

    We present an innovative idea to use hyper-velocity (>30 km/s) high-density (>1017 cm-3) plasma jets of D-T/H and C60-fullerene for magneto-inertial fusion (MIF), high energy density laboratory plasma (HEDLP), and disruption mitigation in magnetic fusion plasma devices. The mass (~1-2 g) of sublimated C60 and hydrogen (or D-T fuel) produced in a pulsed power source is ionized and accelerated as a plasma slug in a coaxial plasma accelerator. For MIF/HEDLP we propose to create a magnetized plasma target by injecting two high-Mach number high-density jets with fuel (D-T) and liner (C60/C) structure along the axis of a pulsed magnetic mirror. The magnetized target fusion (MTF) plasma created by head-on collision and stagnation of jets is compressed radially by a metallic liner (Z-pinch) and axially by the C60/C liner. For disruption mitigation, the C60 plasma jets were shown to be able to provide the required impurity mass (J Fusion Energy 27:6, 2008).

  15. Dynamics of ionization-induced electron injection in the high density regime of laser wakefield acceleration

    SciTech Connect

    Desforges, F. G.; Paradkar, B. S. Ju, J.; Audet, T. L.; Maynard, G.; Cros, B.; Hansson, M.; Senje, L.; Persson, A.; Lundh, O.; Wahlström, C.-G.; Dobosz-Dufrénoy, S.; Monot, P.; Vay, J.-L.

    2014-12-15

    The dynamics of ionization-induced electron injection in high density (∼1.2 × 10{sup 19} cm{sup −3}) regime of laser wakefield acceleration is investigated by analyzing the betatron X-ray emission. In such high density operation, the laser normalized vector potential exceeds the injection-thresholds of both ionization-injection and self-injection due to self-focusing. In this regime, direct experimental evidence of early on-set of ionization-induced injection into the plasma wave is given by mapping the X-ray emission zone inside the plasma. Particle-In-Cell simulations show that this early on-set of ionization-induced injection, due to its lower trapping threshold, suppresses the trapping of self-injected electrons. A comparative study of the electron and X-ray properties is performed for both self-injection and ionization-induced injection. An increase of X-ray fluence by at least a factor of two is observed in the case of ionization-induced injection due to increased trapped charge compared to self-injection mechanism.

  16. Spike Detection for Large Neural Populations Using High Density Multielectrode Arrays

    PubMed Central

    Muthmann, Jens-Oliver; Amin, Hayder; Sernagor, Evelyne; Maccione, Alessandro; Panas, Dagmara; Berdondini, Luca; Bhalla, Upinder S.; Hennig, Matthias H.

    2015-01-01

    An emerging generation of high-density microelectrode arrays (MEAs) is now capable of recording spiking activity simultaneously from thousands of neurons with closely spaced electrodes. Reliable spike detection and analysis in such recordings is challenging due to the large amount of raw data and the dense sampling of spikes with closely spaced electrodes. Here, we present a highly efficient, online capable spike detection algorithm, and an offline method with improved detection rates, which enables estimation of spatial event locations at a resolution higher than that provided by the array by combining information from multiple electrodes. Data acquired with a 4096 channel MEA from neuronal cultures and the neonatal retina, as well as synthetic data, was used to test and validate these methods. We demonstrate that these algorithms outperform conventional methods due to a better noise estimate and an improved signal-to-noise ratio (SNR) through combining information from multiple electrodes. Finally, we present a new approach for analyzing population activity based on the characterization of the spatio-temporal event profile, which does not require the isolation of single units. Overall, we show how the improved spatial resolution provided by high density, large scale MEAs can be reliably exploited to characterize activity from large neural populations and brain circuits. PMID:26733859

  17. Evolutionary Agroecology: the potential for cooperative, high density, weed-suppressing cereals

    PubMed Central

    Weiner, Jacob; Andersen, Sven B; Wille, Wibke K-M; Griepentrog, Hans W; Olsen, Jannie M

    2010-01-01

    Evolutionary theory can be applied to improve agricultural yields and/or sustainability, an approach we call Evolutionary Agroecology. The basic idea is that plant breeding is unlikely to improve attributes already favored by millions of years of natural selection, whereas there may be unutilized potential in selecting for attributes that increase total crop yield but reduce plants’ individual fitness. In other words, plant breeding should be based on group selection. We explore this approach in relation to crop-weed competition, and argue that it should be possible to develop high density cereals that can utilize their initial size advantage over weeds to suppress them much better than under current practices, thus reducing or eliminating the need for chemical or mechanical weed control. We emphasize the role of density in applying group selection to crops: it is competition among individuals that generates the ‘Tragedy of the Commons’, providing opportunities to improve plant production by selecting for attributes that natural selection would not favor. When there is competition for light, natural selection of individuals favors a defensive strategy of ‘shade avoidance’, but a collective, offensive ‘shading’ strategy could increase weed suppression and yield in the high density, high uniformity cropping systems we envision. PMID:25567940

  18. On the road to obesity: Television viewing increases intake of high-density foods.

    PubMed

    Blass, Elliott M; Anderson, Daniel R; Kirkorian, Heather L; Pempek, Tiffany A; Price, Iris; Koleini, Melanie F

    2006-07-30

    Television viewing (TVV) has been linked with obesity, possibly through increased sedentary behavior and/or through increased ingestion during TVV. The proposition that TVV causes increased feeding, however, has not been subjected to experimental verification until recently. Our objective was to determine if the amount eaten of two familiar, palatable, high-density foods (pizza and macaroni and cheese) was increased during a 30-min meal when watching TV. In a within-subjects design, one group of undergraduates (n = 10) ate pizza while watching a TV show of their choice for one session and when listening to a symphony during the other session. A second group of undergraduates (n = 10) ate macaroni and cheese (M&C). TVV increased caloric intake by 36% (one slice on average) for pizza and by 71% for M&C. Eating patterns also differed between conditions. Although the length of time to eat a slice of pizza remained stable between viewing conditions, the amount of time before starting another slice was shorter during TVV. In contrast, M&C was eaten at a faster rate and for a longer period of time during TVV. Thus, watching television increases the amount eaten of high-density, palatable, familiar foods and may constitute one vector contributing to the current obesity crisis. PMID:16822530

  19. High-density information transmission and waveguide integration with low crosstalk and propagation loss

    NASA Astrophysics Data System (ADS)

    Guo, Jianjun; Su, Weiheng; Liang, Yao; Zhang, Fengchun; Huang, Xuguang

    2016-03-01

    Photonic waveguides are fundamental components for photonic integrated circuits (PICs). Although a wide spectrum of nanophotonic structures, i.e., silicon waveguides and plasmonic waveguides, have been exploited for optical interconnects, these structures either can only support one polarization or they are not able to be integrated within a 1-μm scale due to strong crosstalk. The hurdle for high-density information transmission and waveguide integration is mainly the lack of a compact waveguide structure that can support different polarization states with low crosstalk. We propose and numerically demonstrate an ultralong-range waveguide that supports both transverse electric- and transverse magnetic-like polarizations. The propagation length of this waveguide is several decimeters with working bandwidths as great as 160 nm for both polarizations. In addition, this design is very compact with a small center-to-center distance of 1 μm between two adjacent waveguides while the isolation is as high as more than 69.3 dB. This waveguide is also able to guide light efficiently through a 90 deg bend with a 1-μm bending radius for both polarizations. Our work opens new perspectives for high-density waveguide integration in PICs, which would benefit various applications with limited physical space, such as on-chip information processing and sensing.

  20. Patterned growth of carbon nanotubes obtained by high density plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Mousinho, A. P.; Mansano, R. D.

    2015-03-01

    Patterned growth of carbon nanotubes by chemical vapor deposition represents an assembly approach to place and orient nanotubes at a stage as early as when they are synthesized. In this work, the carbon nanotubes were obtained at room temperature by High Density Plasmas Chemical Vapor Deposition (HDPCVD) system. This CVD system uses a new concept of plasma generation, where a planar coil coupled to an RF system for plasma generation was used with an electrostatic shield for plasma densification. In this mode, high density plasmas are obtained. We also report the patterned growth of carbon nanotubes on full 4-in Si wafers, using pure methane plasmas and iron as precursor material (seed). Photolithography processes were used to pattern the regions on the silicon wafers. The carbon nanotubes were characterized by micro-Raman spectroscopy, the spectra showed very single-walled carbon nanotubes axial vibration modes around 1590 cm-1 and radial breathing modes (RBM) around 120-400 cm-1, confirming that high quality of the carbon nanotubes obtained in this work. The carbon nanotubes were analyzed by atomic force microscopy and scanning electron microscopy too. The results showed that is possible obtain high-aligned carbon nanotubes with patterned growth on a silicon wafer with high reproducibility and control.