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Sample records for chemical plugs based

  1. Preparation and Characterization of Chemical Plugs Based on Selected Hanford Waste Simulants

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Parker, Kent E.; Cordova, Elsa A.; Gunderson, Katie M.; Baum, Steven R.; Crum, Jarrod V.; Poloski, Adam P.

    2008-09-15

    This report presents the results of preparation and characterization of chemical plugs based on selected Hanford Site waste simulants. Included are the results of chemical plug bench testing conducted in support of the M1/M6 Flow Loop Chemical Plugging/Unplugging Test (TP-RPP-WTP-495 Rev A). These results support the proposed plug simulants for the chemical plugging/ unplugging tests. Based on the available simulant data, a set of simulants was identified that would likely result in chemical plugs. The three types of chemical plugs that were generated and tested in this task consisted of: 1. Aluminum hydroxide (NAH), 2. Sodium aluminosilicate (NAS), and 3. Sodium aluminum phosphate (NAP). While both solvents, namely 2 molar (2 M) nitric acid (HNO3) and 2 M sodium hydroxide (NaOH) at 60°C, used in these tests were effective in dissolving the chemical plugs, the 2 M nitric acid was significantly more effective in dissolving the NAH and NAS plugs. The caustic was only slightly more effecting at dissolving the NAP plug. In the bench-scale dissolution tests, hot (60°C) 2 M nitric acid was the most effective solvent in that it completely dissolved both NAH and NAS chemical plugs much faster (1.5 – 2 x) than 2 M sodium hydroxide. So unless there are operational benefits for the use of caustic verses nitric acid, 2 M nitric acid heated to 60°C C should be the solvent of choice for dissolving these chemical plugs. Flow-loop testing was planned to identify a combination of parameters such as pressure, flush solution, composition, and temperature that would effectively dissolve and flush each type of chemical plug from preformed chemical plugs in 3-inch-diameter and 4-feet-long pipe sections. However, based on a review of the results of the bench-top tests and technical discussions, the Waste Treatment Plant (WTP) Research and Technology (R&T), Engineering and Mechanical Systems (EMS), and Operations concluded that flow-loop testing of the chemically plugged pipe

  2. The chemical-in-plug bacterial chemotaxis assay is prone to false positive responses

    PubMed Central

    2010-01-01

    Background Chemical-in-plug assays are commonly used to study bacterial chemotaxis, sometimes in the absence of stringent controls. Results We report that non-chemotactic and non-motile mutants in two distinct bacterial species (Shewanella oneidensis and Helicobacter pylori) show apparent zones of accumulation or clearing around test plugs containing potential attractants or repellents, respectively. Conclusions Our results suggest that the chemical-in-plug assay should be used with caution, that non-motile or non-chemotactic mutants should be employed as controls, and that results should be confirmed with other types of assays. PMID:20233446

  3. The plug-based nanovolume Microcapillary Protein Crystallization System (MPCS)

    SciTech Connect

    Gerdts, Cory J.; Elliott, Mark; Lovell, Scott; Mixon, Mark B.; Napuli, Alberto J.; Staker, Bart L.; Nollert, Peter; Stewart, Lance

    2012-02-08

    The Microcapillary Protein Crystallization System (MPCS) embodies a new semi-automated plug-based crystallization technology which enables nanolitre-volume screening of crystallization conditions in a plasticware format that allows crystals to be easily removed for traditional cryoprotection and X-ray diffraction data collection. Protein crystals grown in these plastic devices can be directly subjected to in situ X-ray diffraction studies. The MPCS integrates the formulation of crystallization cocktails with the preparation of the crystallization experiments. Within microfluidic Teflon tubing or the microfluidic circuitry of a plastic CrystalCard, {approx}10-20 nl volume droplets are generated, each representing a microbatch-style crystallization experiment with a different chemical composition. The entire protein sample is utilized in crystallization experiments. Sparse-matrix screening and chemical gradient screening can be combined in one comprehensive 'hybrid' crystallization trial. The technology lends itself well to optimization by high-granularity gradient screening using optimization reagents such as precipitation agents, ligands or cryoprotectants.

  4. The comparison of removing plug by ultrasonic wave, chemical deplugging agent and ultrasound-chemical combination deplugging for near-well ultrasonic processing technology.

    PubMed

    Wang, Zhenjun; Xu, Yuanming; Bajracharya, Suman

    2015-11-01

    Near-well ultrasonic processing technology is characterized by high adaptability, simple operation, low cost and zero pollution. The main plugs of oil production include paraffin deposition plug, polymer plug, and drilling fluid plug etc. Although some good results have been obtained through laboratory experiments and field tests, systematic and intensive studies are absent for certain major aspects, such as: effects of ultrasonic treatment for different kinds of plugs and whether effect of ultrasound-chemicals combination deplugging is better than that of ultrasonic deplugging. In this paper, the experiments of removing drilling fluid plug, paraffin deposition plug and polymer plug by ultrasonic wave, chemical deplugging agent and ultrasound-chemical combination deplugging respectively are carried out. Results show that the effect of ultrasound-chemical combination deplugging is clearly better than that of using ultrasonic wave and chemical deplugging agent separately, which indicates that ultrasonic deplugging and chemical deplugging can produce synergetic effects. On the one hand, ultrasonic treatment can boost the activity of chemical deplugging agent and turn chemical deplugging into dynamic chemical process, promoting chemical agent reaction speed and enhancing deplugging effect; on the other hand, chemical agent can reduce the adhesion strength of plugs so that ultrasonic deplugging effect can be improved significantly. Experimental results provide important reference for near-well ultrasonic processing technology.

  5. The comparison of removing plug by ultrasonic wave, chemical deplugging agent and ultrasound-chemical combination deplugging for near-well ultrasonic processing technology.

    PubMed

    Wang, Zhenjun; Xu, Yuanming; Bajracharya, Suman

    2015-11-01

    Near-well ultrasonic processing technology is characterized by high adaptability, simple operation, low cost and zero pollution. The main plugs of oil production include paraffin deposition plug, polymer plug, and drilling fluid plug etc. Although some good results have been obtained through laboratory experiments and field tests, systematic and intensive studies are absent for certain major aspects, such as: effects of ultrasonic treatment for different kinds of plugs and whether effect of ultrasound-chemicals combination deplugging is better than that of ultrasonic deplugging. In this paper, the experiments of removing drilling fluid plug, paraffin deposition plug and polymer plug by ultrasonic wave, chemical deplugging agent and ultrasound-chemical combination deplugging respectively are carried out. Results show that the effect of ultrasound-chemical combination deplugging is clearly better than that of using ultrasonic wave and chemical deplugging agent separately, which indicates that ultrasonic deplugging and chemical deplugging can produce synergetic effects. On the one hand, ultrasonic treatment can boost the activity of chemical deplugging agent and turn chemical deplugging into dynamic chemical process, promoting chemical agent reaction speed and enhancing deplugging effect; on the other hand, chemical agent can reduce the adhesion strength of plugs so that ultrasonic deplugging effect can be improved significantly. Experimental results provide important reference for near-well ultrasonic processing technology. PMID:26186853

  6. Microfluidic plug steering using surface acoustic waves.

    PubMed

    Sesen, Muhsincan; Alan, Tuncay; Neild, Adrian

    2015-07-21

    Digital microfluidic systems, in which isolated droplets are dispersed in a carrier medium, offer a method to study biological assays and chemical reactions highly efficiently. However, it's challenging to manipulate these droplets in closed microchannel devices. Here, we present a method to selectively steer plugs (droplets with diameters larger than the channel's width) at a specially designed Y-junction within a microfluidic chip. The method makes use of surface acoustic waves (SAWs) impinging on a multiphase interface in which an acoustic contrast is present. As a result, the liquid-liquid interface is subjected to acoustic radiation forces. These forces are exploited to steer plugs into selected branches of the Y-junction. Furthermore, the input power can be finely tuned to split a plug into two uneven plugs. The steering of plugs as a whole, based on plug volume and velocity is thoroughly characterized. The results indicate that there is a threshold plug volume after which the steering requires elevated electrical energy input. This plug steering method can easily be integrated to existing lab-on-a-chip devices and it offers a robust and active plug manipulation technique in closed microchannels.

  7. Microfluidic plug steering using surface acoustic waves.

    PubMed

    Sesen, Muhsincan; Alan, Tuncay; Neild, Adrian

    2015-07-21

    Digital microfluidic systems, in which isolated droplets are dispersed in a carrier medium, offer a method to study biological assays and chemical reactions highly efficiently. However, it's challenging to manipulate these droplets in closed microchannel devices. Here, we present a method to selectively steer plugs (droplets with diameters larger than the channel's width) at a specially designed Y-junction within a microfluidic chip. The method makes use of surface acoustic waves (SAWs) impinging on a multiphase interface in which an acoustic contrast is present. As a result, the liquid-liquid interface is subjected to acoustic radiation forces. These forces are exploited to steer plugs into selected branches of the Y-junction. Furthermore, the input power can be finely tuned to split a plug into two uneven plugs. The steering of plugs as a whole, based on plug volume and velocity is thoroughly characterized. The results indicate that there is a threshold plug volume after which the steering requires elevated electrical energy input. This plug steering method can easily be integrated to existing lab-on-a-chip devices and it offers a robust and active plug manipulation technique in closed microchannels. PMID:26079216

  8. Chemical aspects of iron colloid plugging in quartz sands and implications for formation damage

    SciTech Connect

    Potter, J.M.; Dibble, W.E.

    1985-09-01

    A research direction having great potential for better understanding of formation damage is the influence of colloid plugging on fluid flow behavior in porous media. Using flow through experimental equipment, we have explored the dependence of the degree of ferric oxyhydroxide colloid plugging of quartz sand packs on the solution pH and anion type at a constant temperature of 208/sup 0/F (97.7/sup 0/C). At a pH of 5, permeability reductions were greatest in the order PO/sup 3//sub 4/-, SO/sup 2//sub 4/-, and Cl-. This order was reversed at a pH of 9. The results suggest that plugging occurs by two fundamentally different mechanisms. First, flocculation/coagulation of the ferric hydroxide leads to formation of filter cake in the low-pH case. Second, colloid/quartz surface interaction produces a more uniform accumulation of colloid throughout the core at higher pH's.

  9. Plugging meter

    DOEpatents

    Nagai, Akinori

    1979-01-01

    A plugging meter for automatically measuring the impurity concentration in a liquid metal is designed to have parallel passages including a cooling passage provided with a plugging orifice and with a flow meter, and a by-pass passage connected in series to a main passage having another flow meter, so that the plugging points may be obtained from the outputs of both flow meters. The plugging meter has a program signal generator, a flow-rate ratio setter and a comparator, and is adapted to change the temperature of the plugging orifice in accordance with a predetermined pattern or gradient, by means of a signal representative of the temperature of plugging orifice and a flow-rate ratio signal obtained from the outputs of both flow meters. This plugging meter affords an automatic and accurate measurement of a multi-plugging phenomenon taking place at the plugging orifice.

  10. SSVEP-based BCI: A "Plug & play" approach.

    PubMed

    Mora, Niccoló; De Munari, Ilaria; Ciampolini, Paolo

    2015-01-01

    Brain-Computer Interface (BCI) can provide users with an alternative/augmentative interaction path, based on the interpretation of their brain activity. Steady State Visual Evoked Potentials (SSVEP) paradigm has many appealing features, aiming at implementing BCI-enabled communication-control applications. In this paper, we present a complete signal processing chain for a self-paced, SSVEP-based BCI. The proposed approach mostly focuses at reducing the user effort in dealing with BCI, featuring no need of user-specific calibration or training. In this paper, the classification algorithm is introduced and first validated on offline waveforms, aiming at improving classification accuracy and minimizing the false positive rate. Then, implementation of an online, self-paced SSVEP BCI is illustrated. The scheme refers to a four-way choice and exploits discrimination between intentional control states and nocontrol ones. Good performance is achieved, both in terms of true positive rate (>94%), as well as low false positive rate (0.26 min(-1)), even in experiments carried out outside lab-controlled conditions.

  11. Plug valve

    DOEpatents

    Wordin, John J.

    1989-01-01

    An improved plug valve wherein a novel shape for the valve plug and valve chamber provide mating surfaces for improved wear characteristics. The novel shape of the valve plug is a frustum of a body of revolution of a curved known as a tractrix, a solid shape otherwise known as a peudosphere.

  12. Photochemically crosslinked collagen annulus plug: a potential solution solving the leakage problem of cell-based therapies for disc degeneration.

    PubMed

    Chik, T K; Ma, X Y; Choy, T H; Li, Y Y; Diao, H J; Teng, W K; Han, S J; Cheung, K M C; Chan, B P

    2013-09-01

    Intra-disc injection of mesenchymal stem cells (MSCs) to treat disc degeneration may lead to unfavorable complications, particularly osteophyte formation. Development of an effective method to block the injection portal, prevent the leakage of injected cells and materials and, hence, prevent osteophyte formation is of the utmost importance before MSC-based therapies can be applied in a clinical setting. Here we seek to alleviate the cell leakage problem and the associated complication osteophyte formation by developing an injectable annulus plug to block the injection portal during intra-disc delivery. Specifically, we fabricated a needle-shaped collagen plug by photochemical crosslinking and successfully delivered it intra-discally, in association with MSCs in collagen microsphere carriers, using a custom-made delivery device. The mechanical performance of the plug and its effectiveness in reducing cell leakage were evaluated ex vivo under compression and in torsion push-out tests. The results demonstrate that the plug survived physiologically relevant loadings and significantly reduced leakage and enhanced retention of the injected materials. Finally, a pilot in vivo study in rabbits was conducted to evaluate the performance of the plug. Microcomputed tomography imaging and histology revealed that the plug significantly reduced osteophyte formation. This work suggests the potential of the annulus plug as an adjunct or annulus closure device for intra-disc delivery of cells and materials.

  13. Spectroscopic Characterization and Simulation of Chemical Sputtering Using the DiMES Porous Plug Injector in DIII-D

    SciTech Connect

    McLean, A G; Davis, J W; Stangeby, P C; Brooks, N H; Whyte, D G; Allen, S L; Bray, B D; Brezinsek, S; Elder, J D; Fenstermacher, M E; Groth, M; Haasz, A A; Hollmann, E M; Isler, R; Lasnier, C J; Rudakov, D L; Watkins, J G; West, W P; Wong, C C

    2006-05-15

    A self-contained gas injection system for the Divertor Material Evaluation System (DiMES) on DIII-D has been employed for in-situ study of chemical erosion in the tokamak divertor environment. The Porous Plug Injector (PPI) releases methane, a major component of molecular influx due to chemical sputtering of graphite, from the tile surface into the plasma at a controlled rate through a porous graphite surface. Perturbation to local plasma is minimized, while also simulating the immediate environment of methane molecules released from a solid graphite surface. The release rate was chosen to be of the same order of magnitude as natural sputtering. Photon efficiencies of CH{sub 4} for measured local plasma conditions are reported. The contribution of chemical versus physical sputtering to the source of C{sup +} at the target is assessed through measurement of CII and CD/CH band emissions during release of CH{sub 4} from the PPI, and due to intrinsic emission.

  14. CRUSDE: A plug-in based simulation framework for composable CRUstal DEformation studies using Green's functions

    NASA Astrophysics Data System (ADS)

    Grapenthin, R.

    2014-01-01

    CRUSDE is a plug-in based simulation framework written in C/C++ for Linux platforms (installation information, download and test cases: http://www.grapenthin.org/crusde). It utilizes Green's functions for simulations of the Earth's response to changes in surface loads. Such changes could involve, for example, melting glaciers, oscillating snow loads, or lava flow emplacement. The focus in the simulation could be the response of the Earth's crust in terms of stress changes, changes in strain rates, or simply uplift or subsidence and the respective horizontal displacements of the crust (over time). Rather than implementing a variety of specific models, CRUSDE approaches crustal deformation problems from a general formulation in which model elements (Green's function, load function, relaxation function, load history), operators, pre- and postprocessors, as well as input and output routines are independent, exchangeable, and reusable on the basis of a plug-in approach (shared libraries loaded at runtime). We derive the general formulation CRUSDE is based on, describe its architecture and use, and demonstrate its capabilities in a test case. With CRUSDE users can: (1) dynamically select software components to participate in a simulation (through XML experiment definitions), (2) extend the framework independently with new software components and reuse existing ones, and (3) exchange software components and experiment definitions with other users. CRUSDE's plug-in mechanism aims for straightforward extendability allowing modelers to add new Earth models/response functions. Current Green's function implementations include surface displacements due to the elastic response, final relaxed response, and pure thick plate response for a flat Earth. These can be combined to express exponential decay from elastic to final relaxed response, displacement rates due to one or multiple disks, irregular loads, or a combination of these. Each load can have its own load history and

  15. On-Chip Titration of an Anticoagulant Argatroban and Determination of the Clotting Time within Whole Blood or Plasma Using a Plug-Based Microfluidic System

    PubMed Central

    Song, Helen; Li, Hung-Wing; Munson, Matthew S.; Van Ha, Thuong G.; Ismagilov, Rustem F.

    2006-01-01

    This paper describes extending plug-based microfluidics to handling complex biological fluids such as blood, solving the problem of injecting additional reagents into plugs, and applying this system to measuring of clotting time in small volumes of whole blood and plasma. Plugs are droplets transported through microchannels by fluorocarbon fluids. A plug-based microfluidic system was developed to titrate an anticoagulant (argatroban) into blood samples and to measure the clotting time using the activated partial thromboplastin time (APTT) test. To carry out these experiments, the following techniques were developed for a plug-based system: (i) using Teflon AF coating on the microchannel wall to enable formation of plugs containing blood and transport of the solid fibrin clots within plugs, (ii) using a hydrophilic glass capillary to enable reliable merging of a reagent from an aqueous stream into plugs, (iii) using bright-field microscopy to detect the formation of a fibrin clot within plugs and using fluorescent microscopy to detect the production of thrombin using a fluorogenic substrate, and (iv) titration of argatroban (0–1.5 μg/mL) into plugs and measurement of the resulting APTTs at room temperature (23 °C) and physiological temperature (37 °C). APTT measurements were conducted with normal pooled plasma (platelet-poor plasma) and with donor’s blood samples (both whole blood and platelet-rich plasma). APTT values and APTT ratios measured by the plug-based microfluidic device were compared to the results from a clinical laboratory at 37 °C. APTT obtained from the on-chip assay were about double those from the clinical laboratory but the APTT ratios from these two methods agreed well with each other. PMID:16841902

  16. CrusDe: A plug-in based simulation framework for composable CRUStal DEformation simulations

    NASA Astrophysics Data System (ADS)

    Grapenthin, R.

    2008-12-01

    -in based approach of software component composition the user gets to sample the pleasures of software reuse in a simulation framework: a XML model definition allows for quick parameter adjustment and --more importantly-- straightforward exchange of model elements. The generic communication layer coupled with a plug-in mechanism furthermore allow the user to implement new plug-ins. Here CrusDe supports the reuse of existing components within these new implementations. In this way CrusDe can be adjusted to new flavors of equation~1 without the necessity to re-implement all of the new formal model. An example would be to replace the currently included flat Earth approximations by Green's functions that support spherical geometries. The advantages of the presented approach for software reuse go beyond the comforts for single users who will spent less time on test and validation of model formulations. Opportunities to increase the transparency of research open up since CrusDe is freely available as open source software for Linux/Unix platforms and model formulations are compact enough to include them in publications. Hence, the possibilities for reproduction of model results are greatly enhanced. Due to its modular architecture parts or the whole of CrusDe could become part of other projects. For example, a free repository of Green's functions can evolve or CrusDe could be used as an isostasy module in a larger modeling context. class="ab'>

  17. Cost Analysis of Plug-In Hybred Electric Vehicles Using GPS-Based Longitudinal Travel Data

    SciTech Connect

    Wu, Xing; Dong, Jing; Lin, Zhenhong

    2014-01-01

    Using spatial, longitudinal travel data of 415 vehicles over 3 18 months in the Seattle metropolitan area, this paper estimates the operating costs of plug-in hybrid electric vehicles (PHEVs) of various electric ranges (10, 20, 30, and 40 miles) for 3, 5, and 10 years of payback period, considering different charging infrastructure deployment levels and gasoline prices. Some key findings were made. (1) PHEVs could help save around 60% or 40% in energy costs, compared with conventional gasoline vehicles (CGVs) or hybrid electric vehicles (HEVs), respectively. However, for motorists whose daily vehicle miles traveled (DVMT) is significant, HEVs may be even a better choice than PHEV40s, particularly in areas that lack a public charging infrastructure. (2) The incremental battery cost of large-battery PHEVs is difficult to justify based on the incremental savings of PHEVs operating costs unless a subsidy is offered for largebattery PHEVs. (3) When the price of gasoline increases from $4/gallon to $5/gallon, the number of drivers who benefit from a larger battery increases significantly. (4) Although quick chargers can reduce charging time, they contribute little to energy cost savings for PHEVs, as opposed to Level-II chargers.

  18. Laterally Mobile, Functionalized Self-Assembled Monolayers at the Fluorous−Aqueous Interface in a Plug-Based Microfluidic System: Characterization and Testing with Membrane Protein Crystallization

    SciTech Connect

    Kreutz, Jason E.; Li, Liang; Roach, L. Spencer; Hatakeyama, Takuji; Ismagilov, Rustem F.

    2009-11-04

    This paper describes a method to generate functionalizable, mobile self-assembled monolayers (SAMs) in plug-based microfluidics. Control of interfaces is advancing studies of biological interfaces, heterogeneous reactions, and nanotechnology. SAMs have been useful for such studies, but they are not laterally mobile. Lipid-based methods, though mobile, are not easily amenable to setting up the hundreds of experiments necessary for crystallization screening. Here we demonstrate a method, complementary to current SAM and lipid methods, for rapidly generating mobile, functionalized SAMs. This method relies on plugs, droplets surrounded by a fluorous carrier fluid, to rapidly explore chemical space. Specifically, we implemented his-tag binding chemistry to design a new fluorinated amphiphile, RfNTA, using an improved one-step synthesis of RfOEG under Mitsunobu conditions. RfNTA introduces specific binding of protein at the fluorous-aqueous interface, which concentrates and orients proteins at the interface, even in the presence of other surfactants. We then applied this approach to the crystallization of a his-tagged membrane protein, Reaction Center from Rhodobacter sphaeroides, performed 2400 crystallization trials, and showed that this approach can increase the range of crystal-producing conditions, the success rate at a given condition, the rate of nucleation, and the quality of the crystal formed.

  19. Detecting bacteria and Determining Their Susceptibility to Antibiotics by Stochastic Confinement in Nanoliter Droplets using Plug-Based Microfluidics

    SciTech Connect

    Boedicker, J.; Li, L; Kline, T; Ismagilov, R

    2008-01-01

    This article describes plug-based microfluidic technology that enables rapid detection and drug susceptibility screening of bacteria in samples, including complex biological matrices, without pre-incubation. Unlike conventional bacterial culture and detection methods, which rely on incubation of a sample to increase the concentration of bacteria to detectable levels, this method confines individual bacteria into droplets nanoliters in volume. When single cells are confined into plugs of small volume such that the loading is less than one bacterium per plug, the detection time is proportional to plug volume. Confinement increases cell density and allows released molecules to accumulate around the cell, eliminating the pre-incubation step and reducing the time required to detect the bacteria. We refer to this approach as stochastic confinement. Using the microfluidic hybrid method, this technology was used to determine the antibiogram - or chart of antibiotic sensitivity - of methicillin-resistant Staphylococcus aureus (MRSA) to many antibiotics in a single experiment and to measure the minimal inhibitory concentration (MIC) of the drug cefoxitin (CFX) against this strain. In addition, this technology was used to distinguish between sensitive and resistant strains of S. aureus in samples of human blood plasma. High-throughput microfluidic techniques combined with single-cell measurements also enable multiple tests to be performed simultaneously on a single sample containing bacteria. This technology may provide a method of rapid and effective patient-specific treatment of bacterial infections and could be extended to a variety of applications that require multiple functional tests of bacterial samples on reduced timescales.

  20. Collection of nanoliter microdiaysate fractions in plugs for off-line in vivo chemical monitoring with up to 2 s temporal resolution

    PubMed Central

    Wang, Meng; Slaney, Thomas; Mabrouk, Omar; Kennedy, Robert T.

    2010-01-01

    An off-line in vivo neurochemical monitoring approach was developed based on collecting nanoliter microdialysate fractions as an array of “plugs” segmented by immiscible oil in a piece of Teflon tubing. The dialysis probe was integrated with the plug generator in a polydimethlysiloxane microfluidic device that could be mounted on the subject. The microfluidic device also allowed derivatization reagents to be added to the plugs for fluorescence detection of analytes. Using the device, 2 nL fractions corresponding to 1–20 ms sampling times depending upon dialysis flow rate, were collected. Because axial dispersion was prevented between them, each plug acted as a discrete sample collection vial and temporal resolution was not lost by mixing or diffusion during transport. In vitro tests of the system revealed that the temporal resolution of the system was as good as 2 s and was limited by mass transport effects within the dialysis probe. After collection of dialysate fractions, they were pumped into a glass microfluidic chip that automatically analyzed the plugs by capillary electrophoresis with laser-induced fluorescence at 50 s intervals. By using a relatively low flow rate during transfer to the chip, the temporal resolution of the samples could be preserved despite the relatively slow analysis time. The system was used to detect rapid dynamics in neuroactive amino acids evoked by microinjecting the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (PDC) or K+ into the striatum of anesthetized rats. The resulted showed increases in neurotransmitter efflux that reached a peak in 20 s for PDC and 13 s for K+. PMID:20447417

  1. A stochastic model of turbulent mixing with chemical reaction: Nitric oxide formulation in a plug-flow burner

    NASA Technical Reports Server (NTRS)

    Flagan, R. C.; Appleton, J. P.

    1973-01-01

    A stochastic model of turbulent mixing was developed for a reactor in which mixing is represented by n-body fluid particle interactions. The model was used to justify the assumption (made in previous investigations of the role of turbulent mixing on burner generated thermal nitric oxide and carbon monoxide emissions) that for a simple plug flow reactor, composition nonuniformities can be described by a Gaussian distribution function in the local fuel:air equivalence ratio. Recent extensions of this stochastic model to include the combined effects of turbulent mixing and secondary air entrainment on thermal generation of nitric oxide in gas turbine combustors are discussed. Finally, rate limited upper and lower bounds of the nitric oxide produced by thermal fixation of molecular nitrogen and oxidation of organically bound fuel nitrogen are estimated on the basis of the stochastic model for a plug flow burner; these are compared with experimental measurements obtained using a laboratory burner operated over a wide range of test conditions; good agreement is obtained.

  2. Plug and drill template

    NASA Technical Reports Server (NTRS)

    Orella, S.

    1979-01-01

    Device installs plugs and then drills them after sandwich face sheets are in place. Template guides drill bit into center of each concealed plug thereby saving considerable time and fostering weight reduction with usage of smaller plugs.

  3. Fast hydrothermal liquefaction for production of chemicals and biofuels from wet biomass - The need to develop a plug-flow reactor.

    PubMed

    Tran, Khanh-Quang

    2016-08-01

    Hydrothermal liquefaction (HTL) is a promising technology for converting wet plant biomass directly to liquid fuels and chemicals. However, some aspects of the technology are not fully understood and still disputed. The reactor material constraints and difficulties coupled with the formation of unwanted products are the main challenges limiting the applications of the technology. In addition, heat and mass transfer limitations in the reaction system result in a lower conversion efficiency and selectivity, of which the later would make it difficult and expensive for products separation, purification, and/or modification of the products. This paper discusses the challenges and current status of possible solutions to the challenges, focusing on the need of developing a special plug-flow reactor for scaling up of the HTL process. PMID:27085989

  4. Fast hydrothermal liquefaction for production of chemicals and biofuels from wet biomass - The need to develop a plug-flow reactor.

    PubMed

    Tran, Khanh-Quang

    2016-08-01

    Hydrothermal liquefaction (HTL) is a promising technology for converting wet plant biomass directly to liquid fuels and chemicals. However, some aspects of the technology are not fully understood and still disputed. The reactor material constraints and difficulties coupled with the formation of unwanted products are the main challenges limiting the applications of the technology. In addition, heat and mass transfer limitations in the reaction system result in a lower conversion efficiency and selectivity, of which the later would make it difficult and expensive for products separation, purification, and/or modification of the products. This paper discusses the challenges and current status of possible solutions to the challenges, focusing on the need of developing a special plug-flow reactor for scaling up of the HTL process.

  5. Evaluation of plug-in electric vehicles impact on cost-based unit commitment

    NASA Astrophysics Data System (ADS)

    Talebizadeh, Ehsan; Rashidinejad, Masoud; Abdollahi, Amir

    2014-02-01

    Incorporating plug in electric vehicles (PEVs) to power systems may address both additional demand as well as mobile storage to support electric grid spatially. Better utilization of such potential depends on the optimal scheduling of charging and discharging PEVs. Charging management malfunction of PEVs may increase the peak load which leads to additional generation. Therefore, charging and discharging of PEVs must be scheduled intelligently to prevent overloading of the network at peak hours, take advantages of off peak charging benefits and delaying any load shedding. A charging and discharging schedule of PEVs with respect to load curve variations is proposed in this paper. The proposed methodology incorporates integrated PEVs; the so-called parking lots; into the unit commitment problem. An IEEE 10-unit test system is employed to investigate the impacts of PEVs on generation scheduling. The results obtained from simulation analysis show a significant techno-economic saving.

  6. Characterization of Chemical Sputtering Using the Mark II DIMES Porous Plug Injector in Attached and Semi-detached Divertor Plasmas of DIII-D

    SciTech Connect

    McLean, A. G.; Davis, J. W.; Stangeby, P. C.; Allen, S. L.; Boedo, J. A.; Bray, B. D.; Brezinsek, S.; Brooks, N. H.; Fenstermacher, M. E.; Groth, M.; Haasz, A. A.; Hollmann, E. M.; Isler, Ralph C; Lasnier, C. J.; Mu, Y.; Petrie, T. W.; Rudakov, D. L.; Watkins, J. G.; West, W. P.; Whyte, D. G.; Wong, C. P. C.

    2009-01-01

    An improved, self-contained gas injection system for the divertor material evaluation system (DIMES) on DIII-D has been employed for in situ study of chemical erosion in the tokamak divertor environment. To minimize perturbation to local plasma, the Mark II porous plug injector (PPI) releases methane through a porous graphite surface at the outer strike point at a rate precisely controlled by a micro-orifice flow restrictor to be approximately equal as that predicted for intrinsic chemical sputtering. Effective photon efficiencies resulting from CH(4) are found to be 58 +/- 12 in an attached divertor (n(e) similar to 1.5 x 10(13)/cm(3), T(e) similar to 25 eV, T(surf)similar to 450 K), and 94 +/- 20 in a semi-detached cold divertor (n(e) similar to 6.0 x 10(13)/cm(3), T(e) similar to 2-3 eV, T(surf) similar to 350 K). These values are significantly more than previous measurements in similar plasma conditions, indicating the importance of the injection rate and local re-erosion for the integrity of this analysis. The contribution of chemical versus physical sputtering to the source of C(+) at the target is assessed through simultaneous measurement of CII line, and CD plus CH-band emissions during release of CH(4) from the Pill, then compared with that seen in intrinsic sputtering. (C) 2009 Elsevier B.V. All rights reserved.

  7. Energy management of a power-split plug-in hybrid electric vehicle based on genetic algorithm and quadratic programming

    NASA Astrophysics Data System (ADS)

    Chen, Zheng; Mi, Chris Chunting; Xiong, Rui; Xu, Jun; You, Chenwen

    2014-02-01

    This paper introduces an online and intelligent energy management controller to improve the fuel economy of a power-split plug-in hybrid electric vehicle (PHEV). Based on analytic analysis between fuel-rate and battery current at different driveline power and vehicle speed, quadratic equations are applied to simulate the relationship between battery current and vehicle fuel-rate. The power threshold at which engine is turned on is optimized by genetic algorithm (GA) based on vehicle fuel-rate, battery state of charge (SOC) and driveline power demand. The optimal battery current when the engine is on is calculated using quadratic programming (QP) method. The proposed algorithm can control the battery current effectively, which makes the engine work more efficiently and thus reduce the fuel-consumption. Moreover, the controller is still applicable when the battery is unhealthy. Numerical simulations validated the feasibility of the proposed controller.

  8. Time-resolved analysis of biological reactions based on heterogeneous assays in liquid plugs of nanoliter volume.

    PubMed

    Rendl, Martin; Brandstetter, Thomas; Rühe, Jürgen

    2013-10-15

    In this article, we present a concept which uses liquid plugs as reaction volumes for heterogeneous assay reactions to facilitate time-resolved analysis of biomolecular reactions. For this purpose, the reaction is first compartmentalized to a train of many identical plugs. Therefore, we established a simple fluidic setup build from off-the-shelf available tubing and connectors. It permits reliable formation of plugs and successive dosing of further assay reagents to these compartments (plug volume <5% CV). The time course of the reaction is obtained by routing the plugs successively through a detector. Thereby, the arrival time of a given plug at the detector represents the reaction time of the overall reaction at that moment. Thus, each analyzed plug represents a discrete state of the overall reaction. With this approach, we can achieve a temporal resolution as small as one second, which hardly can be met by conventional analytical methods for analysis of endogenous biological compounds. For analysis of the content of the plugs, we developed a method which allows for heterogeneous assays in two-phase flow. For this purpose, functionalized superparamagnetic beads are enclosed in the plugs for specific binding of the assay product. Purification from supernatant species is achieved by transferring the beads with bound analyte across the phase boundary between aqueous plugs and water-immiscible carrier fluid. We demonstrate this assay principle exemplarily for a sandwich immunoassay (cytokine IL-8). Time-resolved analysis is validated by monitoring a cell-free in vitro expression reaction (turboGFP) in plugs and conventionally in bulk solution. We show that our approach allows for analyzing the entire course of a reaction in a single run. It permits kinetic studies of biological processes with significantly reduced experimental effort and consumption of costly reagents. PMID:24083685

  9. Implementation Approach for Plug-in Electric Vehicles at Joint Base Lewis McChord. Task 4

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2014-12-01

    This study focused on Joint Base Lewis McChord (JBLM), which is located in Washington State. Task 1 consisted of a survey of the non-tactical fleet of vehicles at JBLM to begin the review of vehicle mission assignments and the types of vehicles in service. In Task 2, daily operational characteristics of select vehicles were identified and vehicle movements were recorded in data loggers in order to characterize the vehicles’ missions. In Task 3, the results of the data analysis and observations were provided. Individual observations of the selected vehicles provided the basis for recommendations related to PEV adoption (i.e., whether a battery electric vehicle or plug-in hybrid electric vehicle [collectively referred to as PEVs] can fulfill the mission requirements0, as well as the basis for recommendations related to placement of PEV charging infrastructure. This report focuses on an implementation plan for the near-term adoption of PEVs into the JBLM fleet.

  10. Selective plugging strategy-based microbial-enhanced oil recovery using Bacillus licheniformis TT33.

    PubMed

    Suthar, Harish; Hingurao, Krushi; Desai, Anjana; Nerurkar, Anuradha

    2009-10-01

    The selective plugging strategy of microbial enhanced oil recovery involves the use of microbes that grow and produce exopolymeric substances, which block the high permeability zones of an oil reservoir, thus allowing the water to flow through the low permeability zones leading to increase in oil recovery. Bacillus licheniformis TT33, a hot water spring isolate, is facultatively anaerobic, halotolerant, and thermotolerant. It produces EPS as well as biosurfactant and has a biofilm-forming ability. The viscosity of its cell-free supernatant is 120 mPas at 28 degrees C. Its purified EPS contained 26% carbohydrate and 3% protein. Its biosurfactant reduced the surface tension of water from 72 to 34 mN/m. This strain gave 27.7+/-3.5% oil recovery in a sand pack column. Environmental scanning electron microscopy analysis showed bacterial growth and biofilm formation in the sand pack. Biochemical tests and amplified ribosomal DNA restriction analysis confirmed that the oil recovery obtained in the sand pack column was due to Bacillus licheniformis TT33. PMID:19884785

  11. TelluSim: A Python Plug-in Based Computational Framework for Spatially Distributed Environmental and Earth Sciences Modelling

    NASA Astrophysics Data System (ADS)

    Willgoose, G. R.

    2008-12-01

    TelluSim is a python-based computational framework for integrating and manipulating modules written in a variety of computer languages. TelluSim consists of a main program that dynamically, at run time, assembles a series of modules. These modules can be written in any language that can be accessed by Python. Currently we have modules in Fortran and Python, with C to be supported soon. New modules are incorporated as plug-ins like done for a browser or Photoshop, simply by copying the module binary into a plug-in directory. TelluSim automatically generates a GUI for parameter and state I/O, and automatically creates the intermodule communication mechanisms needed for the computations. A decision to use Python was arrived at after detailed trials using other languages including C, Tcl/Tk and Fortran. An important aspect of the design of TelluSim was to minimise the overhead in interfacing the modules with TelluSim, and minimise any requirement for recoding of existing software, so eliminating a major disadvantage of more complex frameworks (e.g. JAMS, openMI). Several significant Fortran codes developed by the author have been incorporated as part of the design process and as proof of concept. In particular the SIBERIA landform evolution code (a high performance F90 code, including parallel capability) has been broken up into a series of TelluSim modules, so that the SIBERIA now consists of a Python script of 20 lines. These 20 lines assemble and run the underlying modules (about 50,000 lines of Fortran code). The presentation will discuss in more detail the design of TelluSim, and our experiences of the advantages and disadvantages of using Python relative to other approaches.

  12. Rotating arc spark plug

    DOEpatents

    Whealton, John H.; Tsai, Chin-Chi

    2003-05-27

    A spark plug device includes a structure for modification of an arc, the modification including arc rotation. The spark plug can be used in a combustion engine to reduce emissions and/or improve fuel economy. A method for operating a spark plug and a combustion engine having the spark plug device includes the step of modifying an arc, the modifying including rotating the arc.

  13. Improved plug valve computer-aided design of plug element

    SciTech Connect

    Wordin, J.J.

    1990-02-01

    The purpose of this document is to present derivations of equations for the design of a plug valve and to present a computer program which performs the design calculations based on the derivations. The valve is based on a plug formed from a tractrix of revolution called a pseudosphere. It is of interest to be able to calculate various parameters for the plug for design purposes. For example, the surface area, volume, and center of gravity are important to determine friction and wear of the valve. A computer program in BASIC has been written to perform the design calculations. The appendix contains a computer program listing and verifications of results using approximation methods. A sample run is included along with necessary computer commands to run the program. 1 fig.

  14. Analysis of Plug-In hybrid Electric Vehicles' utility factors using GPS-based longitudinal travel data

    NASA Astrophysics Data System (ADS)

    Aviquzzaman, Md

    The benefit of using a Plug-in Hybrid Electric Vehicle (PHEV) comes from its ability of substituting gasoline with electricity in operation. Defined as the share of distance traveled in the electric mode, the utility factor (UF) depends mostly on the battery capacity but also on many other factors, such as travel pattern and recharging pattern. Conventionally, the UFs are calculated from the daily vehicle miles traveled (DVMT) of vehicles by assuming motorists leaving home in the morning with full battery and return home in the evening. Such assumption, however, ignores the impact of the heterogeneity in both travel and charging behavior. The main objective of the thesis is to compare the UF by using multiday GPS-based travel data in regards to the charging decision. This thesis employs the global positioning system (GPS) based longitudinal travel data (covering 3-18 months) collected from 403 vehicles in the Seattle metropolitan area to investigate the impacts of such travel and charging behavior on UFs by analyzing the DVMT and home and work related tours. The UFs based on the DVMT are found close to those based on home-to-home tours. On the other hand, it is seen that the workplace charge opportunities largely improve UFs if the battery capacity is no more than 50 miles. It is also found that the gasoline price does not have significant impact on the UFs.

  15. Assessment of Charging Infrastructure for Plug-in Electric Vehicles at Marine Corps Base Camp Lejeune. Task 3

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-11-01

    Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for the U.S. Department of Energy’s advanced vehicle testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (Intertek) to conduct several U.S. Department of Defense-based studies to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 consisted of a survey of the non-tactical fleet of vehicles at Marine Corps Base Camp Lejeune to begin the review of vehicle mission assignments and types of vehicles in service. Task 2 selected vehicles for further monitoring and involved identifying daily operational characteristics of these select vehicles. Data logging of vehicle movements was initiated in order to characterize the vehicle’s mission. The Task 3 vehicle utilization report provided results of the data analysis and observations related to the replacement of current vehicles with PEVs. Finally, this report provides an assessment of charging infrastructure required to support the suggested PEV replacements. Intertek acknowledges the support of Idaho National Laboratory, Marine Corps headquarters, and Marine Corps Base Camp Lejeune Fleet management and personnel for participation in this study. Intertek is pleased to provide this report and is encouraged by enthusiasm and support from Marine Corps Base Camp Lejeune personnel.

  16. Optimal economy-based battery degradation management dynamics for fuel-cell plug-in hybrid electric vehicles

    NASA Astrophysics Data System (ADS)

    Martel, François; Kelouwani, Sousso; Dubé, Yves; Agbossou, Kodjo

    2015-01-01

    This work analyses the economical dynamics of an optimized battery degradation management strategy intended for plug-in hybrid electric vehicles (PHEVs) with consideration given to low-cost technologies, such as lead-acid batteries. The optimal management algorithm described herein is based on discrete dynamic programming theory (DDP) and was designed for the purpose of PHEV battery degradation management; its operation relies on simulation models using data obtained experimentally on a physical PHEV platform. These tools are first used to define an optimal management strategy according to the economical weights of PHEV battery degradation and the secondary energy carriers spent to manage its deleterious effects. We then conduct a sensitivity study of the proposed optimization process to the fluctuating economic parameters associated with the fuel and energy costs involved in the degradation management process. Results demonstrate the influence of each parameter on the process's response, including daily total operating costs and expected battery lifetime, as well as establish boundaries for useful application of the method; in addition, they provide a case for the relevance of inexpensive battery technologies, such as lead-acid batteries, for economy-centric PHEV applications where battery degradation is a major concern.

  17. The frequency and chemical composition of rocky planetary debris around young white dwarfs: Plugging the last gaps

    NASA Astrophysics Data System (ADS)

    Gaensicke, Boris

    2014-10-01

    Many planetary systems will survive the post main-sequence evolution of their host stars into white dwarfs (WDs). In the solar system, Mars, the asteroid belt, and the outer planets will eventually orbit the WD remnant of the Sun, and many WDs are known to have remnants of planetary systems. Historically, planetary debris was detected in ~20% of WDs with cooling ages >0.5Gyr from Ca K detections. However, the Ca II ionisation balance makes the ground-based detection of planetary debris at younger, hotter WDs impossible.We have carried out a very successful Cycle 18/19 COS snapshot survey of 100 WDs with cooling ages of 20-200Myr, and detect metal pollution in up to 50% of all targets via the strong Si resonance lines. This survey also showed that terrestrial material is common around A-stars, that rocky exo-planetary bodies display a similar variety in abundances as the meteorites in our solar system, and that water-rich Ceres-like asteroids still exist in evolved planetary systems. We propose to close the last gaps in the statistics of evolved planetary systems: an extension of our snapshot survey to cooling ages of 5-25Myr and 100-300Myr. Our orbital integrations suggest that mass-loss during the AGB phase can stirr up instabilities leading to planet-planet collisions, which should be most frequent during the first 10Myr, and the proposed observations will unambiguously test these predictions. In addition, the extended sample will improve the statistics on the formation of planetary systems as a function of host star mass, and build up a deeper insight into the abundances of rocky exo-planetary material that will guide models of terrestrial planet formation

  18. MANTA, a novel plug-based vascular closure device for large bore arteriotomies: technical report.

    PubMed

    van Gils, Lennart; Daemen, Joost; Walters, Greg; Sorzano, Todd; Grintz, Todd; Nardone, Sam; Lenzen, Mattie; De Jaegere, Peter P T; Roubin, Gary; Van Mieghem, Nicolas M

    2016-09-18

    Catheter-based interventions have become a less invasive alternative to conventional surgical techniques for a wide array of cardiovascular diseases but often create large arteriotomies. A completely percutaneous technique is attractive as it may reduce the overall complication rate and procedure time. Currently, large bore arteriotomy closure relies on suture-based techniques. Access-site complications are not uncommon and often seem related to closure device failure. The MANTA VCD is a novel collagen-based closure device that specifically targets arteriotomies between 10 and 22 Fr. This technical report discusses the MANTA design concept, practical instructions for use and preliminary clinical experience. PMID:27639742

  19. Plug and Play web-based visualization of mobile air monitoring data (Abstract)

    EPA Science Inventory

    EPA’s Real-Time Geospatial (RETIGO) Data Viewer web-based tool is a new program reducing the technical barrier to visualize and understand geospatial air data time series collected using wearable, bicycle-mounted, or vehicle-mounted air sensors. The RETIGO tool, with anticipated...

  20. Multi-objective component sizing of a power-split plug-in hybrid electric vehicle powertrain using Pareto-based natural optimization machines

    NASA Astrophysics Data System (ADS)

    Mozaffari, Ahmad; Vajedi, Mahyar; Chehresaz, Maryyeh; Azad, Nasser L.

    2016-03-01

    The urgent need to meet increasingly tight environmental regulations and new fuel economy requirements has motivated system science researchers and automotive engineers to take advantage of emerging computational techniques to further advance hybrid electric vehicle and plug-in hybrid electric vehicle (PHEV) designs. In particular, research has focused on vehicle powertrain system design optimization, to reduce the fuel consumption and total energy cost while improving the vehicle's driving performance. In this work, two different natural optimization machines, namely the synchronous self-learning Pareto strategy and the elitism non-dominated sorting genetic algorithm, are implemented for component sizing of a specific power-split PHEV platform with a Toyota plug-in Prius as the baseline vehicle. To do this, a high-fidelity model of the Toyota plug-in Prius is employed for the numerical experiments using the Autonomie simulation software. Based on the simulation results, it is demonstrated that Pareto-based algorithms can successfully optimize the design parameters of the vehicle powertrain.

  1. Aquarius' Object-Oriented, Plug and Play Component-Based Flight Software

    NASA Technical Reports Server (NTRS)

    Murray, Alexander; Shahabuddin, Mohammad

    2013-01-01

    The Aquarius mission involves a combined radiometer and radar instrument in low-Earth orbit, providing monthly global maps of Sea Surface Salinity. Operating successfully in orbit since June, 2011, the spacecraft bus was furnished by the Argentine space agency, Comision Nacional de Actividades Espaciales (CONAE). The instrument, built jointly by NASA's Caltech/JPL and Goddard Space Flight Center, has been successfully producing expectation-exceeding data since it was powered on in August of 2011. In addition to the radiometer and scatterometer, the instrument contains an command & data-handling subsystem with a computer and flight software (FSW) that is responsible for managing the instrument, its operation, and its data. Aquarius' FSW is conceived and architected as a Component-based system, in which the running software consists of a set of Components, each playing a distinctive role in the subsystem, instantiated and connected together at runtime. Component architectures feature a well-defined set of interfaces between the Components, visible and analyzable at the architectural level (see [1]). As we will describe, this kind of an architecture offers significant advantages over more traditional FSW architectures, which often feature a monolithic runtime structure. Component-based software is enabled by Object-Oriented (OO) techniques and languages, the use of which again is not typical in space mission FSW. We will argue in this paper that the use of OO design methods and tools (especially the Unified Modeling Language), as well as the judicious usage of C++, are very well suited to FSW applications, and we will present Aquarius FSW, describing our methods, processes, and design, as a successful case in point.

  2. Aquarius' Object-Oriented, plug and play component-based flight software

    NASA Astrophysics Data System (ADS)

    Murray, A.; Shahabuddin, M.

    The Aquarius mission involves a combined radiometer and radar instrument in low-Earth orbit, providing monthly global maps of Sea Surface Salinity. Operating successfully in orbit since June, 2011, the spacecraft bus was furnished by the Argentine space agency, Comision Nacional de Actividades Espaciales (CONAE). The instrument, built jointly by NASA's Caltech/JPL and Goddard Space Flight Center, has been successfully producing expectation-exceeding data since it was powered on in August of 2011. In addition to the radiometer and scatterometer, the instrument contains an command & data-handling subsystem with a computer and flight software (FSW) that is responsible for managing the instrument, its operation, and its data. Aquarius' FSW is conceived and architected as a Component based system, in which the running software consists of a set of Components, each playing a distinctive role in the subsystem, instantiated and connected together at runtime. Component architectures feature a well-defined set of interfaces between the Components, visible and analyzable at the architectural level. As we will describe, this kind of an architecture offers significant advantages over more traditional FSW architectures, which often feature a monolithic runtime structure. Component-based software is enabled by Object-Oriented (OO) techniques and languages, the use of which again is not typical in space mission FSW. We will argue in this paper that the use of OO design methods and tools (especially the Unified Modeling Language), as well as the judicious usage of C++, are very well suited to FSW applications, and we will present Aquarius FSW, describing our methods, processes, and design, as a successful case in point.

  3. A Python Plug-in Based Computational Framework for Spatially Distributed Environmental and Earth Sciences Modelling

    NASA Astrophysics Data System (ADS)

    Willgoose, G. R.

    2009-12-01

    One of the pioneering landform evolution models, SIBERIA, while developed in the 1980’s is still widely used in the science community and is a key component of engineering software used to assess the long-term stability of man-made landforms such as rehabilitated mine sites and nuclear waste repositories. While SIBERIA is very reliable, computationally fast and well tested (both its underlying science and the computer code) the range of emerging applications have challenged the ability of the author to maintain and extend the underlying computer code. Moreover, the architecture of the SIBERIA code is not well suited to collaborative extension of its capabilities without often triggering forking of the code base. This paper describes a new modelling framework designed to supersede SIBERIA (as well as other earth sciences codes by the author) called TelluSim. The design is such that it is potentially more than simply a new landform evolution model, but TelluSim is a more general dynamical system modelling framework using time evolving GIS data as its spatial discretisation. TelluSim is designed as an open modular framework facilitating open-sourcing of the code, while addressing compromises made in the original design of SIBERIA in the 1980’s. An important aspect of the design of TelluSim was to minimise the overhead in interfacing the modules with TelluSim, and minimise any requirement for recoding of existing software, so eliminating a major disadvantage of more complex frameworks. The presentation will discuss in more detail the reasoning behind the design of TelluSim, and experiences of the advantages and disadvantages of using Python relative to other approaches (e.g. Matlab, R). The paper will discuss examples of how TelluSim has facilitated the incorporation and testing of new algorithms, and environmental processes, and the support for novel science and data testing methodologies. It will also discuss plans to link TelluSim with other open source

  4. A GAMOS plug-in for GEANT4 based Monte Carlo simulation of radiation-induced light transport in biological media.

    PubMed

    Glaser, Adam K; Kanick, Stephen C; Zhang, Rongxiao; Arce, Pedro; Pogue, Brian W

    2013-05-01

    We describe a tissue optics plug-in that interfaces with the GEANT4/GAMOS Monte Carlo (MC) architecture, providing a means of simulating radiation-induced light transport in biological media for the first time. Specifically, we focus on the simulation of light transport due to the Čerenkov effect (light emission from charged particle's traveling faster than the local speed of light in a given medium), a phenomenon which requires accurate modeling of both the high energy particle and subsequent optical photon transport, a dynamic coupled process that is not well-described by any current MC framework. The results of validation simulations show excellent agreement with currently employed biomedical optics MC codes, [i.e., Monte Carlo for Multi-Layered media (MCML), Mesh-based Monte Carlo (MMC), and diffusion theory], and examples relevant to recent studies into detection of Čerenkov light from an external radiation beam or radionuclide are presented. While the work presented within this paper focuses on radiation-induced light transport, the core features and robust flexibility of the plug-in modified package make it also extensible to more conventional biomedical optics simulations. The plug-in, user guide, example files, as well as the necessary files to reproduce the validation simulations described within this paper are available online at http://www.dartmouth.edu/optmed/research-projects/monte-carlo-software.

  5. Quantum well infrared photodetectors (QWIP) with selectively regrown N-GaAs plugs

    NASA Astrophysics Data System (ADS)

    Matsukura, Yusuke; Nishino, Hironori; Tanaka, Hitoshi; Fujii, Toshio

    2001-10-01

    We fabricated the GaAs/AlGaAs Quantum Well Infrared Photo detector (QWIP) focal plane array with selectively re-grown N- GaAs interconnection plugs and demonstrated its device operation, in order to establish the technology to obtain both complex device functions and device manufacturability. MBE (Molecular Beam Epitaxy) grown QWIP MQW wafers were covered with SiON and SiNx mask films to obtain selectivity of the re-growth process. N-GaAs plugs were re-grown selectively with low-pressure MOCVD (Metal-Organic Chemical Vapor Deposition) with AsH3 and Dimethylgalliumchloride as precursors, only on the bottom surfaces of the holes for the interconnection to extract the electrodes from the underlying epilayer. Cross- sectional SEM observation revealed that the feature of the re- grown N-GaAs plugs was triangular, rather than rectangular as expected. The reason for this discrepancy is not yet clear. The electrical contact between the epilayer and re-grown N- GaAs plug was 'ohmic-like,' without any trace of interfacial barrier. The Current-Voltage characteristics of the fabricated QWIP device showed no tangible leakage current between the N- GaAs plug and device structure, indicating that electrical insulation between the N-GaAs plugs and device structure was sufficient. Fabricated devices were successfully operated as a hybrid focal plane array, indicating the selective re-growth was a promising technique to realize complex QWIP based devices.

  6. Friction pull plug welding: chamfered heat sink pull plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2005-01-01

    The average strength of a pull plug weld is increased and weak bonding eliminated by providing a dual included angle at the top one third of the pull plug. Plugs using the included angle of the present invention had consistent high strength, no weak bonds and were substantially defect free. The dual angle of the pull plug body increases the heat and pressure of the weld in the region of the top one third of the plug. This allows the plug to form a tight high quality solid state bond. The dual angle was found to be successful in elimination of defects on both small and large plugs.

  7. The effects of select factors on the pour point, cloud point, and cold filter plugging point of soybean-, choice white grease-, and corn-based biodiesel blends

    NASA Astrophysics Data System (ADS)

    Jezierski, Kelly

    Soybean-, choice white grease-, and corn-based biodiesel from different sources blended with cold flow modifiers from 0.0% to 4.0% by weight were tested for cloud point (CP), cold filter plugging point (CFPP), and pour point (PP). The soybean-based blend that showed the best result was four weight percent of TechnolRTM B100 Biodiesel Cold Flow Improver used on B99 obtained from Wacker Oil, which resulted in a CP of -3°C, a PP of -18 °C, and a CFPP of -7°C. The TechnolRTM product slightly improved the CFPP of corn-based biodiesel when used at 2.0 weight percent, reducing it from -1°C to -4°C. No significant improvements were observed on choice white grease-based biodiesel blends. It was shown that, CFPP is not a linear function of the CP; the order of cold flow properties here occasionally follows the trend of the Cloud Point being greater than or equal to the Pour Point which is greater than or equal to the Cold Filter Plugging Point; and the source of the biodiesel also has a significant effect on the cold flow properties.

  8. Clearance of a Mucus Plug

    NASA Astrophysics Data System (ADS)

    Bian, Shiyao; Zheng, Ying; Grotberg, James B.

    2008-11-01

    Mucus plugging may occur in pulmonary airways in asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. How to clear the mucus plug is essential and of fundamental importance. Mucus is known to have a yield stress and a mucus plug behaves like a solid plug when the applied stresses are below its yield stress τy. When the local stresses reaches τy, the plug starts to move and can be cleared out of the lung. It is then of great importance to examine how the mucus plug deforms and what is the minimum pressure required to initiate its movement. The present study used the finite element method (FEM) to study the stress distribution and deformation of a solid mucus plug under different pressure loads using ANSYS software. The maximum shear stress is found to occur near the rear transition region of the plug, which can lead to local yielding and flow. The critical pressure increases linearly with the plug length and asymptotes when the plug length is larger than the half channel width. Experimentally a mucus simulant is used to study the process of plug deformation and critical pressure difference required for the plug to propagate. Consistently, the fracture is observed to start at the rear transition region where the plug core connects the films. However, the critical pressure is observed to be dependent on not only the plug length but also the interfacial shape.

  9. Tube plug inspection system

    SciTech Connect

    Pirl, W.E.; Ray, E.A.; Costlow, A.M.; Roth, C.H. Jr.; Gradich, F.X.; Chizmar, D.A.

    1992-03-31

    This patent describes a system for inspecting a tube plug defining a chamber therein and having an open end in communication with the chamber, the chamber having disposed therein an expander element having a bore therethrough. It comprises: probe means having a sensor probe connected thereto for inspecting the tube plug, the probe means capable of being connected to the tube plug for extending the sensor probe a predetermined distance into the chamber through the open end of the tube plug; means connected to the probe means for rotating and translating the sensor probe within the chamber to provide an inspection scan interiorly of the tube plug, the rotating and translating means including: a flexible hose connected to the probe means for translating and rotating the probe means, the hose having adjacent segments so that the hose is flexible; and a connector interposed between adjacent segments of the hose for maintaining the hose in a tangle-free state; and drive means engaging the rotating and translating means for driving the rotating and translating means.

  10. Friction pull plug welding: chamfered heat sink pull plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2002-01-01

    Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Experimental data has shown that the mass of plug heat sink remaining above the top of the plate surface after a weld is completed (the plug heat sink) affects the bonding at the plug top. A minimized heat sink ensures complete bonding of the plug to the plate at the plug top. However, with a minimal heat sink three major problems can arise, the entire plug could be pulled through the plate hole, the central portion of the plug could be separated along grain boundaries, or the plug top hat can be separated from the body. The Chamfered Heat Sink Pull Plug Design allows for complete bonding along the ISL interface through an outside diameter minimal mass heat sink, while maintaining enough central mass in the plug to prevent plug pull through, central separation, and plug top hat separation.

  11. Plug Flow Reactor Simulator

    SciTech Connect

    Larson, Richard S.

    1996-07-30

    PLUG is a computer program that solves the coupled steady state continuity, momentum, energy, and species balance equations for a plug flow reactor. Both homogeneous (gas-phase) and heterogenous (surface) reactions can be accommodated. The reactor may be either isothermal or adiabatic or may have a specified axial temperature or heat flux profile; alternatively, an ambient temperature and an overall heat-transfer coefficient can be specified. The crosssectional area and surface area may vary with axial position, and viscous drag is included. Ideal gas behavior and surface site conservation are assumed.

  12. Plug Flow Reactor Simulator

    1996-07-30

    PLUG is a computer program that solves the coupled steady state continuity, momentum, energy, and species balance equations for a plug flow reactor. Both homogeneous (gas-phase) and heterogenous (surface) reactions can be accommodated. The reactor may be either isothermal or adiabatic or may have a specified axial temperature or heat flux profile; alternatively, an ambient temperature and an overall heat-transfer coefficient can be specified. The crosssectional area and surface area may vary with axial position,more » and viscous drag is included. Ideal gas behavior and surface site conservation are assumed.« less

  13. Energy management of power-split plug-in hybrid electric vehicles based on simulated annealing and Pontryagin's minimum principle

    NASA Astrophysics Data System (ADS)

    Chen, Zheng; Mi, Chunting Chris; Xia, Bing; You, Chenwen

    2014-12-01

    In this paper, an energy management method is proposed for a power-split plug-in hybrid electric vehicle (PHEV). Through analyzing the PHEV powertrain, a series of quadratic equations are employed to approximate the vehicle's fuel-rate, using battery current as the input. Pontryagin's Minimum Principle (PMP) is introduced to find the battery current commands by solving the Hamiltonian function. Simulated Annealing (SA) algorithm is applied to calculate the engine-on power and the maximum current coefficient. Moreover, the battery state of health (SOH) is introduced to extend the application of the proposed algorithm. Simulation results verified that the proposed algorithm can reduce fuel-consumption compared to charge-depleting (CD) and charge-sustaining (CS) mode.

  14. Playing with Plug-ins

    ERIC Educational Resources Information Center

    Thompson, Douglas E.

    2013-01-01

    In today's complex music software packages, many features can remain unexplored and unused. Software plug-ins--available in most every music software package, yet easily overlooked in the software's basic operations--are one such feature. In this article, I introduce readers to plug-ins and offer tips for purchasing plug-ins I have…

  15. Vascular plugs - A key companion to Interventionists - 'Just Plug it'.

    PubMed

    Ramakrishnan, Sivasubramanian

    2015-01-01

    Vascular plugs are ideally suited to close extra-cardiac, high flowing vascular communications. The family of vascular plugs has expanded. Vascular plugs in general have a lower profile and the newer variants can be delivered even through a diagnostic catheter. These features make them versatile and easy to use. The Amplatzer vascular plugs are also used for closing intracardiac defects including coronary arterio-venous fistula and paravalvular leakage in an off-label fashion. In this review, the features of currently available vascular plugs are reviewed along with tips and tricks of using them in the cardiac catheterization laboratory.

  16. Vascular plugs - A key companion to Interventionists - 'Just Plug it'.

    PubMed

    Ramakrishnan, Sivasubramanian

    2015-01-01

    Vascular plugs are ideally suited to close extra-cardiac, high flowing vascular communications. The family of vascular plugs has expanded. Vascular plugs in general have a lower profile and the newer variants can be delivered even through a diagnostic catheter. These features make them versatile and easy to use. The Amplatzer vascular plugs are also used for closing intracardiac defects including coronary arterio-venous fistula and paravalvular leakage in an off-label fashion. In this review, the features of currently available vascular plugs are reviewed along with tips and tricks of using them in the cardiac catheterization laboratory. PMID:26304581

  17. 5.6 μm quantum cascade lasers based on a two-material active region composition with a room temperature wall-plug efficiency exceeding 28%

    NASA Astrophysics Data System (ADS)

    Lyakh, A.; Suttinger, M.; Go, R.; Figueiredo, P.; Todi, A.

    2016-09-01

    5.6 μm quantum cascade lasers based on the Al0.78In0.22As/In0.69Ga0.31As active region composition with the measured pulsed room temperature wall plug efficiency of 28.3% are reported. Injection efficiency for the upper laser level of 75% was measured for the design by testing devices with variable cavity lengths. A threshold current density of 1.7 kA/cm2 and a slope efficiency of 4.9 W/A were measured for uncoated 3.15 mm × 9 μm lasers. Threshold current density and slope efficiency dependence on temperature in the range from 288 K to 348 K for the structure can be described by characteristic temperatures T0 ˜ 140 K and T1 ˜ 710 K, respectively.

  18. Enhanced wall-plug efficiency in AlGaN-based deep-ultraviolet light-emitting diodes with uniform current spreading p-electrode structures

    NASA Astrophysics Data System (ADS)

    Hao, Guo-Dong; Taniguchi, Manabu; Tamari, Naoki; Inoue, Shin-ichiro

    2016-06-01

    The current crowding is an especially severe issue in AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) because of the low conductivity of the n-AlGaN cladding layer that has a high Al fraction. We theoretically investigated the improvement in internal quantum efficiency and total resistances in DUV-LEDs with an emission wavelength of 265 nm by a well-designed p-electrode geometry to produce uniform current spreading. As a result, the wall-plug efficiency was enhanced by a factor of 60% at an injection current of 350 mA in the designed uniform-current-spreading p-electrode LED when compared with an LED with a conventional cross-bar p-electrode pattern.

  19. AlGaAs ridge laser with 33% wall-plug efficiency at 100 °C based on a design of experiments approach

    NASA Astrophysics Data System (ADS)

    Fecioru, Alin; Boohan, Niall; Justice, John; Gocalinska, Agnieszka; Pelucchi, Emanuele; Gubbins, Mark A.; Mooney, Marcus B.; Corbett, Brian

    2016-04-01

    Upcoming applications for semiconductor lasers present limited thermal dissipation routes demanding the highest efficiency devices at high operating temperatures. This paper reports on a comprehensive design of experiment optimisation for the epitaxial layer structure of AlGaAs based 840 nm lasers for operation at high temperature (100 °C) using Technology Computer-Aided Design software. The waveguide thickness, Al content, doping level, and quantum well thickness were optimised. The resultant design was grown and the fabricated ridge waveguides were optimised for carrier injection and, at 100 °C, the lasers achieve a total power output of 28 mW at a current of 50 mA, a total slope efficiency 0.82 W A-1 with a corresponding wall-plug efficiency of 33%.

  20. Ranking chemicals based on chronic toxicity data.

    PubMed

    De Rosa, C T; Stara, J F; Durkin, P R

    1985-12-01

    During the past 3 years, EPA's ECAO/Cincinnati has developed a method to rank chemicals based on chronic toxicity data. This ranking system reflects two primary attributes of every chemical: the minimum effective dose and the type of effect elicited at that dose. The purpose for developing this chronic toxicity ranking system was to provide the EPA with the technical background required to adjust the RQs of hazardous substances designated in Section 101(14) of CERCLA or "Superfund." This approach may have applications to other areas of interest to the EPA and other regulatory agencies where ranking of chemicals based on chronic toxicity is desired. PMID:3843499

  1. Laser-based detection of chemical contraband

    NASA Astrophysics Data System (ADS)

    Clemmer, Robert G.; Kelly, James F.; Martin, Steven W.; Mong, Gary M.; Sharpe, Steven W.

    1997-02-01

    The goal of our work is tow fold; 1) develop a portable and rapid laser based air sampler for detection of specific chemical contraband and 2) compile a spectral data base in both the near- and mid-IR of sufficiently high quality to be useful for gas phase spectroscopic identification of chemical contraband. During the synthesis or 'cooking' of many illicit chemical substances, relatively high concentrations of volatile solvents, chemical precursors and byproducts are unavoidably released to the atmosphere. In some instances, the final product may have sufficient vapor pressure to be detectable in the surrounding air. The detection of a single high-value effluent or the simultaneous detection of two or more low-value effluents can be used as reliable indicators of a nearby clandestine cooking operation. The designation of high- versus low-value effluent reflects both the commercial availability and legitimate usage of a specific chemical. This paper will describe PNNL's progress and efforts towards the development of a portable laser based air sampling system for the detection of clandestine manufacturing of methamphetamine. Although our current efforts ar focused on methamphetamine, we see no fundamental limitations on detection of other forms of chemical contraband manufacturing. This also includes the synthesis of certain classes of chemical weapons that have recently been deployed by terrorist groups.

  2. Numerical Simulation of Sediment Plug Formation in Alluvial Channels

    NASA Astrophysics Data System (ADS)

    Posner, A. J.; Duan, J. G.

    2011-12-01

    A sediment plug is the aggregation of sediment in a river reach that completely blocks the original channel resulting in plug growth upstream by accretion and flooding in surrounding areas. Sediment plugs historically form over relatively short periods, in many cases a matter of weeks. Although sediment plugs are much more common in reach constrictions associated with large woody debris, the mouths of tributaries, and along coastal regions, this investigation focuses on sediment plug formation in an alluvial river. During high flows in the years 1991, 1995, 2005, and 2008, a sediment plug formed in the San Marcial reach of the Middle Rio Grande. The Bureau of Reclamation has had to spend millions of dollars dredging the channel to restore flows to Elephant Butte Reservoir. The hydrodynamic and sediment transport processes, associated with plug formation, occurring in this reach are driven by 1) a flow constriction associated with a rock outcrop, 2) a railroad bridge, and 3) the water level of the downstream reservoir. The three-dimensional hydrodynamic model, Delft3D, was implemented to determine the hydrodynamic and sediment transport parameters and variables required to simulate plug formation in an effort to identify hydro- and morphodynamic thresholds. Several variables were identified by previous studies as metrics for plug formation. These variables were used in our investigation to detect the relative magnitude of each process. Both duration and degree of high flow events were simulated, along with extent of cohesive sediment deposits, reservoir level, and percent of fines in suspended sediment distribution. Results of this analysis illustrate that this model is able to reproduce the sediment plug formation. Model calibration was based on measured water levels and changes in bathymetry using both sediment transport and morphologic change parameters. Changes to hydraulic and sediment parameters are not proportional to morphologic changes and are asymptotic in

  3. Friction pull plug welding: top hat plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2002-01-01

    Friction Pull Plug Welding is a solid state repair process for defects up to one inch in length, only requiring single sided tooling, or outside skin line (OSL), for preferred usage on flight hardware. The most prevalent defect associated with Friction Pull Plug Welding (FPPW) was a top side or inside skin line (ISL) lack of bonding. Bonding was not achieved at this location due to the reduction in both frictional heat and welding pressure between the plug and plate at the end of the weld. Thus, in order to eliminate the weld defects and increase the plug strength at the plug `top` a small `hat` section is added to the pull plug for added frictional heating and pressure.

  4. Friction pull plug welding: top hat plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2001-01-01

    Friction Pull Plug Welding is a solid state repair process for defects up to one inch in length, only requiring single sided tooling, or outside skin line (OSL), for preferred usage on flight hardware. The most prevalent defect associated with Friction Pull Plug Welding (FPPW) was a top side or inside skin line (ISL) lack of bonding. Bonding was not achieved at this location due to the reduction in both frictional heat and welding pressure between the plug and plate at the end of the weld. Thus, in order to eliminate the weld defects and increase the plug strength at the plug `top` a small `hat` section is added to the pull plug for added frictional heating and pressure.

  5. The Use of Immobilized Cytochrome P4502C9 in PMMA-Based Plug-Flow Bioreactors for the Production of Drug Metabolites

    PubMed Central

    Wollenberg, Lance A.; Kabulski, Jarod L.; Powell, Matthew J.; Chen, Jifeng; Flora, Darcy R.; Tracy, Timothy S.; Gannett, Peter M.

    2013-01-01

    Cytochrome P450 enzymes play a key role in the metabolism of pharmaceutical agents. To determine metabolite toxicity, it is necessary to obtain P450 metabolites from various pharmaceutical agents. Here, we describe a bioreactor that is made by immobilizing cytochrome P450 2C9 (CYP2C9) to a poly (methyl methacrylate) surface and, as an alternative to traditional chemical synthesis, can be used to biosynthesize P450 metabolites in a plug-flow bioreactor. As part of the development of the CYP2C9 bioreactor, we have studied two different methods of attachment: 1) coupling via the N-terminus using N-hydroxysulfosuccinimide 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and 2) using the Ni(II) chelator 1-acetato-4-benzyl-triazacyclononane to coordinate the enzyme to the surface using a C-terminal histidine tag. Additionally, the propensity for metabolite production of the CYP2C9 proof-of-concept bioreactors as a function of enzyme attachment conditions (e.g., time and enzyme concentration) was examined. Our results show that the immobilization of CYP2C9 enzymes to a PMMA surface represents a viable and alternative approach to the preparation of CYP2C9 metabolites for toxicity testing. Furthermore, the basic approach can be adapted to any cytochrome P450 enzyme and in a high-throughput, automated process. PMID:24166101

  6. Unbalanced-flow, fluid-mixing plug with metering capabilities

    NASA Technical Reports Server (NTRS)

    England, John Dwight (Inventor); Kelley, Anthony R. (Inventor); Van Buskirk, Paul D. (Inventor)

    2009-01-01

    A fluid mixer plug has holes formed therethrough such that a remaining portion is closed to fluid flow. The plug's inlet face defines a central circuit region and a ring-shaped region with the ring-shaped region including at least some of the plug's remaining portion so-closed to fluid flow. This remaining portion or closed region at each radius R of the ring shaped region satisfies a radius independent, flow-based relationship. Entry openings are defined in the plug's inlet face in correspondence with the holes. The entry openings define an open flow area at each radius of the ring-shaped region. The open flow area at each such radius satisfies the inverse of the flow-based relationship defining the closed regions of the plug.

  7. 662-E solid waste silo-plug lifting analysis

    SciTech Connect

    Mertz, G.E.

    1993-03-01

    The Intermediate Level Tritium Vault No. 1, 662-E, Cell No. 1 contains 140 waste silos. Each silo is approximately 25 feet deep, 30 inches in diameter at the top and covered by a reinforced concrete plug. Two No. 4 reinforcing bars project from the top of each plug for lifting. During lifting operations, the 1.5 inch concrete cover over the lifting bars spelled off 16% of the silo plugs. The No. 4 reinforcing bars were also distorted on many of the silo plugs. Thirteen of the plugs have been repaired to date. The existing silo plug lifting bars have a safe working load of 480 pounds per plug, which is less than 1/3 of the dead weight of the silo plug. The safe working load was calculated using the minimum design factor of 3 based on the yield strength or 5 based on the ultimate strength of the material, as per the Savannah River Site Hoisting and Rigging Manual. The existing design calculations were reviewed, and the following items are noted: (1) Adequate concrete cover was not provided over the horizontal portion of the lifting bars. (2) The lifting bars were allowed to yield in bending, which violates the requirements of the Savannah River Site Hoisting and Rigging Manual. (3) The ultimate strain of the lifting bars would be exceeded before the calculated ultimate strength was achieved. Alternative lifting devices are also identified.

  8. Spark Plug Defects and Tests

    NASA Technical Reports Server (NTRS)

    Silsbee, F B; Loeb, L B; Sawyer, L G; Fonseca, E L; Dickinson, H C; Agnew, P G

    1920-01-01

    The successful operation of the spark plug depends to a large extent on the gas tightness of the plug. Part 1 of this report describes the method used for measuring the gas tightness of aviation spark plugs. Part 2 describes the methods used in testing the electrical conductivity of the insulation material when hot. Part 3 describes the testing of the cold dielectric strength of the insulation material, the resistance to mechanical shock, and the final engine test.

  9. Plug Loads Conservation Measures

    2010-12-31

    This software requires inputs of simple plug loads inventory information and calculates the energy and cost benefits of various retrofit opportunities. This tool includes energy conservation measures for: Vending Machine Misers, Delamp Vending Machine, Desktop to Laptop retrofit, CRT to LCD monitors retrofit, Computer Power Management Settings, and Energy Star Refrigerator retrofit. This tool calculates energy savings, demand reduction, cost savings, building life cycle costs including: simple payback, discounted payback, net-present value, and savings tomore » investment ratio. In addition this tool also displays the environmental benefits of a project.« less

  10. Plug Loads Conservation Measures

    SciTech Connect

    Ian Metzger, Jesse Dean

    2010-12-31

    This software requires inputs of simple plug loads inventory information and calculates the energy and cost benefits of various retrofit opportunities. This tool includes energy conservation measures for: Vending Machine Misers, Delamp Vending Machine, Desktop to Laptop retrofit, CRT to LCD monitors retrofit, Computer Power Management Settings, and Energy Star Refrigerator retrofit. This tool calculates energy savings, demand reduction, cost savings, building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  11. Pulse-actuated fuel-injection spark plug

    DOEpatents

    Murray, Ian; Tatro, Clement A.

    1978-01-01

    A replacement spark plug for reciprocating internal combustion engines that functions as a fuel injector and as a spark plug to provide a "stratified-charge" effect. The conventional carburetor is retained to supply the main fuel-air mixture which may be very lean because of the stratified charge. The replacement plug includes a cylindrical piezoelectric ceramic which contracts to act as a pump whenever an ignition pulse is applied to a central rod through the ceramic. The rod is hollow at its upper end for receiving fuel, it is tapered along its lower length to act as a pump, and it is flattened at its lower end to act as a valve for fuel injection from the pump into the cylinder. The rod also acts as the center electrode of the plug, with the spark jumping from the plug base to the lower end of the rod to thereby provide spark ignition that has inherent proper timing with the fuel injection.

  12. Polysaccharides and bacterial plugging

    SciTech Connect

    Fogler, H.S.

    1991-11-01

    Before any successful application of Microbial Enhanced Oil Recovery process can be realized, an understanding of the cells' transport and retentive mechanisms in porous media is needed. Cell transport differs from particle transport in their ability to produce polysaccharides, which are used by cells to adhere to surfaces. Cell injection experiments have been conducted using Leuconostoc cells to illustrate the importance of cellular polysaccharide production as a transport mechanism that hinders cell movement and plugs porous media. Kinetic studies of the Leuconostoc cells, carried out to further understand the plugging rates of porous media, have shown that the cells' growth rates are approximately equal when provided with monosaccharide (glucose and fructose) or sucrose. The only difference in cell metabolism is the production of dextran when sucrose is supplied as a carbon source. Experimentally it has also been shown that the cells' growth rate is weakly dependent upon the sucrose concentration in the media, and strongly dependent upon the concentration of yeast extract. The synthesis of cellular dextran has been found to lag behind cell generation, thus indicating that the cells need to reach maturity before they are capable of expressing the detransucrase enzyme and synthesizing insoluble dextran. Dextran yields were found to be dependent upon the sucrose concentration in the media. 10 refs., 9 figs., 9 tabs.

  13. Towards a Multifunctional Electrochemical Sensing and Niosome Generation Lab-on-Chip Platform Based on a Plug-and-Play Concept.

    PubMed

    Kara, Adnane; Rouillard, Camille; Mathault, Jessy; Boisvert, Martin; Tessier, Frédéric; Landari, Hamza; Melki, Imene; Laprise-Pelletier, Myriam; Boisselier, Elodie; Fortin, Marc-André; Boilard, Eric; Greener, Jesse; Miled, Amine

    2016-01-01

    In this paper, we present a new modular lab on a chip design for multimodal neurotransmitter (NT) sensing and niosome generation based on a plug-and-play concept. This architecture is a first step toward an automated platform for an automated modulation of neurotransmitter concentration to understand and/or treat neurodegenerative diseases. A modular approach has been adopted in order to handle measurement or drug delivery or both measurement and drug delivery simultaneously. The system is composed of three fully independent modules: three-channel peristaltic micropumping system, a three-channel potentiostat and a multi-unit microfluidic system composed of pseudo-Y and cross-shape channels containing a miniature electrode array. The system was wirelessly controlled by a computer interface. The system is compact, with all the microfluidic and sensing components packaged in a 5 cm × 4 cm × 4 cm box. Applied to serotonin, a linear calibration curve down to 0.125 mM, with a limit of detection of 31 μ M was collected at unfunctionalized electrodes. Added sensitivity and selectivity was achieved by incorporating functionalized electrodes for dopamine sensing. Electrode functionalization was achieved with gold nanoparticles and using DNA and o-phenylene diamine polymer. The as-configured platform is demonstrated as a central component toward an "intelligent" drug delivery system based on a feedback loop to monitor drug delivery. PMID:27240377

  14. Towards a Multifunctional Electrochemical Sensing and Niosome Generation Lab-on-Chip Platform Based on a Plug-and-Play Concept

    PubMed Central

    Kara, Adnane; Rouillard, Camille; Mathault, Jessy; Boisvert, Martin; Tessier, Frédéric; Landari, Hamza; Melki, Imene; Laprise-Pelletier, Myriam; Boisselier, Elodie; Fortin, Marc-André; Boilard, Eric; Greener, Jesse; Miled, Amine

    2016-01-01

    In this paper, we present a new modular lab on a chip design for multimodal neurotransmitter (NT) sensing and niosome generation based on a plug-and-play concept. This architecture is a first step toward an automated platform for an automated modulation of neurotransmitter concentration to understand and/or treat neurodegenerative diseases. A modular approach has been adopted in order to handle measurement or drug delivery or both measurement and drug delivery simultaneously. The system is composed of three fully independent modules: three-channel peristaltic micropumping system, a three-channel potentiostat and a multi-unit microfluidic system composed of pseudo-Y and cross-shape channels containing a miniature electrode array. The system was wirelessly controlled by a computer interface. The system is compact, with all the microfluidic and sensing components packaged in a 5 cm × 4 cm × 4 cm box. Applied to serotonin, a linear calibration curve down to 0.125 mM, with a limit of detection of 31 μM was collected at unfunctionalized electrodes. Added sensitivity and selectivity was achieved by incorporating functionalized electrodes for dopamine sensing. Electrode functionalization was achieved with gold nanoparticles and using DNA and o-phenylene diamine polymer. The as-configured platform is demonstrated as a central component toward an “intelligent” drug delivery system based on a feedback loop to monitor drug delivery. PMID:27240377

  15. Separator plugs for liquid helium

    NASA Technical Reports Server (NTRS)

    Lee, J. M.; Yuan, S. W. K.; Hepler, W. A.; Frederking, T. H. K.

    1984-01-01

    Work performed during Summer 1984 (from June to Sept. 30) in the area of porous media for use in low temperature applications is discussed. Recent applications are in the area of vapor - liquid phase separation, pumping based on the fountain effect and related subsystems. Areas of potential applications of the latter are outlined in supplementary work. Experimental data have been developed. The linear equations of the two-fluid model are inspected critically in the light of forced convection evidence reported recently. It is emphasized that the Darcy permeability is a unique throughput quantity in the porous media application areas whose use will permit meaningful comparisons of data not only in one lab but also within a group of labs doing porous plug studies.

  16. Mechanics Model of Plug Welding

    NASA Technical Reports Server (NTRS)

    Zuo, Q. K.; Nunes, A. C., Jr.

    2015-01-01

    An analytical model has been developed for the mechanics of friction plug welding. The model accounts for coupling of plastic deformation (material flow) and thermal response (plastic heating). The model predictions of the torque, energy, and pull force on the plug were compared to the data of a recent experiment, and the agreements between predictions and data are encouraging.

  17. Rotating plug bearing and seal

    DOEpatents

    Wade, Elman E.

    1977-01-01

    A bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing.

  18. Static Gas-Charging Plug

    NASA Technical Reports Server (NTRS)

    Indoe, William

    2012-01-01

    A gas-charging plug can be easily analyzed for random vibration. The design features two steeped O-rings in a radial configuration at two different diameters, with a 0.050-in. (.1.3-mm) diameter through-hole between the two O-rings. In the charging state, the top O-ring is engaged and sealing. The bottom O-ring outer diameter is not squeezed, and allows air to flow by it into the tank. The inner diameter is stretched to plug the gland diameter, and is restrained by the O-ring groove. The charging port bushing provides mechanical stop to restrain the plug during gas charge removal. It also prevents the plug from becoming a projectile when removing gas charge from the accumulator. The plug can easily be verified after installation to ensure leakage requirements are met.

  19. Chemical Sensors Based on Optical Ring Resonators

    NASA Technical Reports Server (NTRS)

    Homer, Margie; Manfreda, Allison; Mansour, Kamjou; Lin, Ying; Ksendzov, Alexander

    2005-01-01

    Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong evanescent-wave coupling between the outer polymer layer and the electromagnetic field propagating along the waveguide core. By virtue of this coupling, the chemically induced change in index of refraction of the polymer causes a measurable shift in the resonance peaks of the ring. In a prototype that has been used to demonstrate the feasibility of this sensor concept, the ring resonator is a dielectric optical waveguide laid out along a closed path resembling a racetrack (see Figure 1). The prototype was fabricated on a silicon substrate by use of standard techniques of thermal oxidation, chemical vapor deposition, photolithography, etching, and spin coating. The prototype resonator waveguide features an inner cladding of SiO2, a core of SixNy, and a chemical-sensing outer cladding of ethyl cellulose. In addition to the ring Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong

  20. Analysis of plug-in hybrid electric vehicles' utility factors using GPS-based longitudinal travel data

    DOE PAGESBeta

    Wu, Xing; Aviquzzaman, Md.; Lin, Zhenhong

    2015-05-29

    The benefit of using a PHEV comes from its ability to substitute gasoline with electricity in operation. Defined as the proportion of distance traveled in the electric mode, the utility factor (UF) depends mostly on the battery capacity, but also on many other factors, such as travel pattern and recharging pattern. Conventionally, the UFs are calculated based on the daily vehicle miles traveled (DVMT) by assuming motorists leave home in the morning with a full battery, and no charge occurs before returning home in the evening. Such an assumption, however, ignores the impact of the heterogeneity in both travel andmore » charging behavior, such as going back home more than once in a day, the impact of available charging time, and the price of gasoline. In addition, the conventional UFs are based on the National Household Travel Survey (NHTS) data, which are one-day travel data of each sample vehicle. A motorist's daily distance variation is ignored. This paper employs the GPS-based longitudinal travel data (covering 3-18 months) collected from 403 vehicles in the Seattle metropolitan area to investigate how such travel and charging behavior affects UFs. To do this, for each vehicle, we organized trips to a series of home and work related tours. The UFs based on the DVMT are found close to those based on home-to-home tours. However, it is seen that the workplace charge opportunities significantly increase UFs if the CD range is no more than 40 miles.« less

  1. Analysis of plug-in hybrid electric vehicles' utility factors using GPS-based longitudinal travel data

    SciTech Connect

    Wu, Xing; Aviquzzaman, Md.; Lin, Zhenhong

    2015-05-29

    The benefit of using a PHEV comes from its ability to substitute gasoline with electricity in operation. Defined as the proportion of distance traveled in the electric mode, the utility factor (UF) depends mostly on the battery capacity, but also on many other factors, such as travel pattern and recharging pattern. Conventionally, the UFs are calculated based on the daily vehicle miles traveled (DVMT) by assuming motorists leave home in the morning with a full battery, and no charge occurs before returning home in the evening. Such an assumption, however, ignores the impact of the heterogeneity in both travel and charging behavior, such as going back home more than once in a day, the impact of available charging time, and the price of gasoline. In addition, the conventional UFs are based on the National Household Travel Survey (NHTS) data, which are one-day travel data of each sample vehicle. A motorist's daily distance variation is ignored. This paper employs the GPS-based longitudinal travel data (covering 3-18 months) collected from 403 vehicles in the Seattle metropolitan area to investigate how such travel and charging behavior affects UFs. To do this, for each vehicle, we organized trips to a series of home and work related tours. The UFs based on the DVMT are found close to those based on home-to-home tours. However, it is seen that the workplace charge opportunities significantly increase UFs if the CD range is no more than 40 miles.

  2. Fail-Safe Pressure Plug

    NASA Technical Reports Server (NTRS)

    Svejkovsky, Paul A.

    1993-01-01

    Protective plug resists slowly built-up pressure or automatically releases itself if pressure rises suddenly. Seals out moisture at pressures ranging from 50 micrometers of mercury to 200 pounds per square inch. Designed to seal throat of 38 Reaction Control Thrusters on Space Shuttle protecting internal components from corrosion. Plug conforms to contour of nozzle throat, where O-ring forms pressure seal. After plug inserted, cover attached by use of cover-fitting assembly. Modified versions useful in protecting engines, pumps, reaction vessels, and other industrial equipment during shipment and maintenance.

  3. Amineborane Based Chemical Hydrogen Storage - Final Report

    SciTech Connect

    Sneddon, Larry G.

    2011-04-21

    The development of efficient and safe methods for hydrogen storage is a major hurdle that must be overcome to enable the use of hydrogen as an alternative energy carrier. The objectives of this project in the DOE Center of Excellence in Chemical Hydride Storage were both to develop new methods for on-demand, low temperature hydrogen release from chemical hydrides and to design high-conversion off-board methods for chemical hydride regeneration. Because of their reactive protic (N-H) and hydridic (B-H) hydrogens and high hydrogen contents, amineboranes such as ammonia borane, NH3BH3 (AB), 19.6-wt% H2, and ammonia triborane NH3B3H7 (AT), 17.7-wt% H2, were initially identified by the Center as promising, high-capacity chemical hydrogen storage materials with the potential to store and deliver molecular hydrogen through dehydrogenation and hydrolysis reactions. In collaboration with other Center partners, the Penn project focused both on new methods to induce amineborane H2-release and on new strategies for the regeneration the amineborane spent-fuel materials. The Penn approach to improving amineborane H2-release focused on the use of ionic liquids, base additives and metal catalysts to activate AB dehydrogenation and these studies successfully demonstrated that in ionic liquids the AB induction period that had been observed in the solid-state was eliminated and both the rate and extent of AB H2-release were significantly increased. These results have clearly shown that, while improvements are still necessary, many of these systems have the potential to achieve DOE hydrogen-storage goals. The high extent of their H2­-release, the tunability of both their H2 materials weight-percents and release rates, and their product control that is attained by either trapping or suppressing unwanted volatile side products, such as borazine, continue to make AB/ionic­-liquid based systems attractive candidates for chemical hydrogen storage applications. These studies also

  4. Plug-and-play Integration of dual-model based Knowledge Artefacts into an Open Source Ehr System.

    PubMed

    Krexner, Rabea; Duftschmid, Georg

    2014-01-01

    In this paper we present our experiences with extending an existing approach for an archetype-compliant collection and export of data according to the openEHR specifications within the open source EHR system OpenMRS. It allows an automatic generation of forms from templates, which were introduced by openEHR as an extension of the dual-model approach. Data entered in these forms can be exported in form of standardized EHR extracts. The use of templates allowed us to solve problems reported for the original archetype-based version of the approach, which were caused by the high optionality within archetypes. PMID:25160154

  5. Carbon-Nanotube-Based Chemical Gas Sensor

    NASA Technical Reports Server (NTRS)

    Kaul, Arunpama B.

    2010-01-01

    Conventional thermal conductivity gauges (e.g. Pirani gauges) lend themselves to applications such as leak detectors, or in gas chromatographs for identifying various gas species. However, these conventional gauges are physically large, operate at high power, and have a slow response time. A single-walled carbon-nanotube (SWNT)-based chemical sensing gauge relies on differences in thermal conductance of the respective gases surrounding the CNT as it is voltage-biased, as a means for chemical identification. Such a sensor provides benefits of significantly reduced size and compactness, fast response time, low-power operation, and inexpensive manufacturing since it can be batch-fabricated using Si integrated-circuit (IC) process technology.

  6. Plug cluster module demonstration

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.

    1978-01-01

    The low pressure, film cooled rocket engine design concept developed during two previous ALRC programs was re-evaluated for application as a module for a plug cluster engine capable of performing space shuttle OTV missions. The nominal engine mixture ratio was 5.5 and the engine life requirements were 1200 thermal cycles and 10 hours total operating life. The program consisted of pretest analysis; engine tests, performed using residual components; and posttest analysis. The pretest analysis indicated that operation of the operation of the film cooled engine at O/F = 5.5 was feasible. During the engine tests, steady state wall temperature and performance measurement were obtained over a range of film cooling flow rates, and the durability of the engine was demonstrated by firing the test engine 1220 times at a nominal performance ranging from 430 - 432 seconds. The performance of the test engine was limited by film coolant sleeve damage which had occurred during previous testing. The post-test analyses indicated that the nominal performance level can be increased to 436 seconds.

  7. Guidable pipe plug

    DOEpatents

    Glassell, Richard L.; Babcock, Scott M.; Lewis, Benjamin E.

    2001-01-01

    A plugging device for closing an opening defined by an end of a pipe with sealant comprises a cap, an extension, an inner seal, a guide, and at least one stop. The cap has an inner surface which defines a chamber adapted for retaining the sealant. The chamber is dimensioned slightly larger than the end so as to receive the end. The chamber and end define a gap therebetween. The extension has a distal end and is attached to the inner surface opposite the distal end. The inner seal is attached to the extension and sized larger than the opening. The guide is positioned forward of the inner seal and attached to the distal end. The guide is also dimensioned to be inserted into the opening. The stop is attached to the extender, and when the stop is disposed in the pipe, the stop is movable with respect to the conduit in one direction and also prevents misalignment of the cap with the pipe. A handle can also be included to allow the cap to be positioned robotically.

  8. A plug-and-play approach to antibody-based therapeutics via a chemoselective dual click strategy

    PubMed Central

    Maruani, Antoine; Smith, Mark E.B.; Miranda, Enrique; Chester, Kerry A.; Chudasama, Vijay; Caddick, Stephen

    2015-01-01

    Although recent methods for the engineering of antibody–drug conjugates (ADCs) have gone some way to addressing the challenging issues of ADC construction, significant hurdles still remain. There is clear demand for the construction of novel ADC platforms that offer greater stability, homogeneity and flexibility. Here we describe a significant step towards a platform for next-generation antibody-based therapeutics by providing constructs that combine site-specific modification, exceptional versatility and high stability, with retention of antibody binding and structure post-modification. The relevance of the work in a biological context is also demonstrated in a cytotoxicity assay and a cell internalization study with HER2-positive and -negative breast cancer cell lines. PMID:25824906

  9. 49 CFR 230.59 - Fusible plugs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Fusible Plugs § 230.59 Fusible plugs. If boilers are equipped with fusible plugs, the plugs shall be removed and cleaned of scale each time the boiler is washed but not less frequently than during every...

  10. 49 CFR 230.59 - Fusible plugs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Fusible Plugs § 230.59 Fusible plugs. If boilers are equipped with fusible plugs, the plugs shall be removed and cleaned of scale each time the boiler is washed but not less frequently than during every...

  11. 49 CFR 230.59 - Fusible plugs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Fusible Plugs § 230.59 Fusible plugs. If boilers are equipped with fusible plugs, the plugs shall be removed and cleaned of scale each time the boiler is washed but not less frequently than during every...

  12. 49 CFR 230.59 - Fusible plugs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Fusible Plugs § 230.59 Fusible plugs. If boilers are equipped with fusible plugs, the plugs shall be removed and cleaned of scale each time the boiler is washed but not less frequently than during every...

  13. 49 CFR 230.59 - Fusible plugs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Fusible Plugs § 230.59 Fusible plugs. If boilers are equipped with fusible plugs, the plugs shall be removed and cleaned of scale each time the boiler is washed but not less frequently than during every...

  14. Field-free particle focusing in microfluidic plugs

    PubMed Central

    Kurup, G. K.; Basu, Amar S.

    2012-01-01

    Particle concentration is a key unit operation in biochemical assays. Although there are many techniques for particle concentration in continuous-phase microfluidics, relatively few are available in multiphase (plug-based) microfluidics. Existing approaches generally require external electric or magnetic fields together with charged or magnetized particles. This paper reports a passive technique for particle concentration in water-in-oil plugs which relies on the interaction between particle sedimentation and the recirculating vortices inherent to plug flow in a cylindrical capillary. This interaction can be quantified using the Shields parameter (θ), a dimensionless ratio of a particle’s drag force to its gravitational force, which scales with plug velocity. Three regimes of particle behavior are identified. When θ is less than the movement threshold (region I), particles sediment to the bottom of the plug where the internal vortices subsequently concentrate the particles at the rear of the plug. We demonstrate highly efficient concentration (∼100%) of 38 μm glass beads in 500 μm diameter plugs traveling at velocities up to 5 mm/s. As θ is increased beyond the movement threshold (region II), particles are suspended in well-defined circulation zones which begin at the rear of the plug. The length of the zone scales linearly with plug velocity, and at sufficiently large θ, it spans the length of the plug (region III). A second effect, attributed to the co-rotating vortices at the rear cap, causes particle aggregation in the cap, regardless of flow velocity. Region I is useful for concentrating/collecting particles, while the latter two are useful for mixing the beads with the solution. Therefore, the two key steps of a bead-based assay, concentration and resuspension, can be achieved simply by changing the plug velocity. By exploiting an interaction of sedimentation and recirculation unique to multiphase flow, this simple technique achieves particle

  15. Thermal energy harvesting plasmonic based chemical sensors.

    PubMed

    Karker, Nicholas; Dharmalingam, Gnanaprakash; Carpenter, Michael A

    2014-10-28

    Detection of gases such as H2, CO, and NO2 at 500 °C or greater requires materials with thermal stability and reliability. One of the major barriers toward integration of plasmonic-based chemical sensors is the requirement of multiple components such as light sources and spectrometers. In this work, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The combination of a plasmonic-based energy harvesting sensing paradigm with PCA analysis offers a novel path toward simplification and integration of plasmonic-based sensing methods. PMID:25280004

  16. Waveguide-based optical chemical sensor

    DOEpatents

    Grace, Karen M.; Swanson, Basil I.; Honkanen, Seppo

    2007-03-13

    The invention provides an apparatus and method for highly selective and sensitive chemical sensing. Two modes of laser light are transmitted through a waveguide, refracted by a thin film host reagent coating on the waveguide, and analyzed in a phase sensitive detector for changes in effective refractive index. Sensor specificity is based on the particular species selective thin films of host reagents which are attached to the surface of the planar optical waveguide. The thin film of host reagents refracts laser light at different refractive indices according to what species are forming inclusion complexes with the host reagents.

  17. CDF End Plug calorimeter Upgrade Project

    SciTech Connect

    Apollinari, G.; de Barbaro, P.; Mishina, M.

    1994-01-01

    We report on the status of the CDF End Plug Upgrade Project. In this project, the CDF calorimeters in the end plug and the forward regions will be replaced by a single scintillator based calorimeter. After an extensive R&D effort on the tile/fiber calorimetry, we have now advanced to a construction phase. We review the results of the R&D leading to the final design of the calorimeters and the development of tooling devised for this project. The quality control program of the production of the electromagnetic and hadronic calorimeters is described. A shower maximum detector for the measurement of the shower centroid and the shower profile of electrons, {gamma} and {pi}{sup 0} has been designed. Its performance requirements, R&D results and mechanical design are discussed.

  18. Chemical Sensors Based on Metal Oxide Nanostructures

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Mike J.; Liu, Chung-Chiun

    2006-01-01

    This paper is an overview of sensor development based on metal oxide nanostructures. While nanostructures such as nanorods show significan t potential as enabling materials for chemical sensors, a number of s ignificant technical challenges remain. The major issues addressed in this work revolve around the ability to make workable sensors. This paper discusses efforts to address three technical barriers related t o the application of nanostructures into sensor systems: 1) Improving contact of the nanostructured materials with electrodes in a microse nsor structure; 2) Controling nanostructure crystallinity to allow co ntrol of the detection mechanism; and 3) Widening the range of gases that can be detected by using different nanostructured materials. It is concluded that while this work demonstrates useful tools for furt her development, these are just the beginning steps towards realizati on of repeatable, controlled sensor systems using oxide based nanostr uctures.

  19. Plug engine systems for future launch vehicle applications

    NASA Astrophysics Data System (ADS)

    Immich, H.; Parsley, R. C.

    1993-06-01

    Based on improved viability resulting from modern analysis techniques, plug nozzle rocket engines are once again being investigated with respect to advanced launch vehicle concepts. The advantage of these engines is the external expansion, which self-adapts to external pressure variation, as well as the short compact design for high expansion ratios. This paper describes feasible design options ranging from a plug nozzle engine with an annular combustion chamber to a segmented modular design, to the integration of a number of conventional engines around a common plug. The advantages and disadvantages of these options are discussed for a range of potential applications including single-stage-to-orbit (SSTO) vehicles, as well as upper stage vehicles such as the second stage of the SAeNGER HTOL launch vehicle concept. Also included is a discussion of how maturing computational fluid dynamic (CFD) modeling techniques could significantly reduce installed performance uncertainties, reducing plug engine development risk.

  20. A rule-based expert system for chemical prioritization using effects-based chemical categories

    EPA Science Inventory

    A rule-based expert system (ES) was developed to predict chemical binding to the estrogen receptor (ER) patterned on the research approaches championed by Gilman Veith to whom this article and journal issue are dedicated. The ERES was built to be mechanistically-transparent and m...

  1. Bentonite borehole plug flow testing with five water types

    SciTech Connect

    Gaudette, M.V.; Daemen, J.J.K.

    1988-04-01

    The hydraulic conductivity has been determined of plugs constructed with commercial precompressed bentonite pellets. Bentonite has been hydrated and tested with waters of five different chemical compositions, including one groundwater (Ogallala aquifer, Texas). The groundwater contained a significant amount of solids: waters prepared in the laboratory did not. Prepared waters used for testing included distilled water, a high (1000 ppM) and a low (45 ppM) calcium solution, and a 39 ppM sodium water. Uncompacted plugs were constructed by dropping bentonite tablets into waterfilled cylinders, or by mixing powdered bentonite with preselected water volumes in order to obtain controlled initial water contents. The hydraulic conductivity of all plugs tested with all waters would result in a classification of practically impervious, by conventional soil mechanics standards. Variations of several orders of magnitude of the hydraulic conductivity are observed.

  2. Data base of chemical explosions in Kazakhstan

    SciTech Connect

    Demin, V.N.; Malahova, M.N.; Martysevich, P.N.; Mihaylova, N.N.; Nurmagambetov, A.; Kopnichev, Yu.F. D.; Edomin, V.I.

    1996-12-01

    Within the bounds of this report, the following works were done: (1) Information about explosion quarries, located in Southern, Eastern and Northern Kasakstan was summarized. (2) The general information about seismicity of areas of location of explosion quarries was adduced. (3) The system of observation and seismic apparatus, recording the local earthquakes and quarry explosions at the territory of Kazakstan were described. (4) Data base of quarry explosions, that were carried out in Southern, Eastern and Northern Kazakstan during 1995 and first half of 1996 year was adduced. (5) Upon the data of registration of explosions in Southern Kazakstan the correlative dependences between power class of explosions and summary weight of charge were constructed. (6) Seismic records of quarry explosions were adduced. It is necessary to note, that the collection of data about quarry explosions in Kazakstan in present time is very difficult task. Organizations, that makes these explosions, are always suffering reorganizations and sometimes it is actually impossible to receive all the necessary information. Some quarries are situated in remote, almost inaccessible regions, and within the bounds of supplier financing not the every quarry was in success to visit. So the present data base upon the chemical explosions for 1995 is not full and in further it`s expansion is possible.

  3. Comparison of Experimental Data and Computations Fluid Dynamics Analysis for a Three Dimensional Linear Plug Nozzle

    NASA Technical Reports Server (NTRS)

    Ruf, J. H.; Hagemann, G.; Immich, H.

    2003-01-01

    A three dimensional linear plug nozzle of area ratio 12.79 was designed by EADS Space Transportation (former Astrium Space Infrastructure). The nozzle was tested within the German National Technology Program 'LION' in a cold air wind tunnel by TU Dresden. The experimental hardware and test conditions are described. Experimental data was obtained for the nozzle without plug side wall fences at a nozzle pressure ratio of 116 and then with plug side wall fences at NPR 110. Schlieren images were recorded and axial profiles of plug wall static pressures were measured at several spanwise locations and on the plug base. Detailed CFD analysis was performed for these nozzle configurations at NPR 116 by NASA MSFC. The CFD exhibits good agreement with the experimental data. A detailed comparison of the CFD results and the experimental plug wall pressure data are given. Comparisons are made for both the without and with plug side wall fence configurations. Numerical results for density gradient are compared to experimental Schlieren images. Experimental nozzle thrust efficiencies are calculated based on the CFD results. The CFD results are used to illustrate the plug nozzle fluid dynamics. The effect of the plug side wall is emphasized.

  4. Effects-based chemical category approach for prioritization of low affinity estrogenic chemicals.

    PubMed

    Hornung, M W; Tapper, M A; Denny, J S; Kolanczyk, R C; Sheedy, B R; Hartig, P C; Aladjov, H; Henry, T R; Schmieder, P K

    2014-01-01

    Regulatory agencies are charged with addressing the endocrine disrupting potential of large numbers of chemicals for which there is often little or no data on which to make decisions. Prioritizing the chemicals of greatest concern for further screening for potential hazard to humans and wildlife is an initial step in the process. This paper presents the collection of in vitro data using assays optimized to detect low affinity estrogen receptor (ER) binding chemicals and the use of that data to build effects-based chemical categories following QSAR approaches and principles pioneered by Gilman Veith and colleagues for application to environmental regulatory challenges. Effects-based chemical categories were built using these QSAR principles focused on the types of chemicals in the specific regulatory domain of concern, i.e. non-steroidal industrial chemicals, and based upon a mechanistic hypothesis of how these non-steroidal chemicals of seemingly dissimilar structure to 17ß-estradiol (E2) could interact with the ER via two distinct binding types. Chemicals were also tested to solubility thereby minimizing false negatives and providing confidence in determination of chemicals as inactive. The high-quality data collected in this manner were used to build an ER expert system for chemical prioritization described in a companion article in this journal.

  5. Effects-based chemical category approach for prioritization of low affinity estrogenic chemicals.

    PubMed

    Hornung, M W; Tapper, M A; Denny, J S; Kolanczyk, R C; Sheedy, B R; Hartig, P C; Aladjov, H; Henry, T R; Schmieder, P K

    2014-01-01

    Regulatory agencies are charged with addressing the endocrine disrupting potential of large numbers of chemicals for which there is often little or no data on which to make decisions. Prioritizing the chemicals of greatest concern for further screening for potential hazard to humans and wildlife is an initial step in the process. This paper presents the collection of in vitro data using assays optimized to detect low affinity estrogen receptor (ER) binding chemicals and the use of that data to build effects-based chemical categories following QSAR approaches and principles pioneered by Gilman Veith and colleagues for application to environmental regulatory challenges. Effects-based chemical categories were built using these QSAR principles focused on the types of chemicals in the specific regulatory domain of concern, i.e. non-steroidal industrial chemicals, and based upon a mechanistic hypothesis of how these non-steroidal chemicals of seemingly dissimilar structure to 17ß-estradiol (E2) could interact with the ER via two distinct binding types. Chemicals were also tested to solubility thereby minimizing false negatives and providing confidence in determination of chemicals as inactive. The high-quality data collected in this manner were used to build an ER expert system for chemical prioritization described in a companion article in this journal. PMID:24779616

  6. Reduced-dimension model of liquid plug propagation in tubes

    NASA Astrophysics Data System (ADS)

    Fujioka, Hideki; Halpern, David; Ryans, Jason; Gaver, Donald P.

    2016-09-01

    We investigate the flow resistance caused by the propagation of a liquid plug in a liquid-lined tube and propose a simple semiempirical formula for the flow resistance as a function of the plug length, the capillary number, and the precursor film thickness. These formulas are based on computational investigations of three key contributors to the plug resistance: the front meniscus, the plug core, and the rear meniscus. We show that the nondimensional flow resistance in the front meniscus varies as a function of the capillary number and the precursor film thickness. For a fixed capillary number, the flow resistance increases with decreasing precursor film thickness. The flow in the core region is modeled as Poiseuille flow and the flow resistance is a linear function of the plug length. For the rear meniscus, the flow resistance increases monotonically with decreasing capillary number. We investigate the maximum mechanical stress behavior at the wall, such as the wall pressure gradient, the wall shear stress, and the wall shear stress gradient, and propose empirical formulas for the maximum stresses in each region. These wall mechanical stresses vary as a function of the capillary number: For semi-infinite fingers of air propagating through pulmonary airways, the epithelial cell damage correlates with the pressure gradient. However, for shorter plugs the front meniscus may provide substantial mechanical stresses that could modulate this behavior and provide a major cause of cell injury when liquid plugs propagate in pulmonary airways. Finally, we propose that the reduced-dimension models developed herein may be of importance for the creation of large-scale models of interfacial flows in pulmonary networks, where full computational fluid dynamics calculations are untenable.

  7. Hot cell shield plug extraction apparatus

    DOEpatents

    Knapp, Philip A.; Manhart, Larry K.

    1995-01-01

    An apparatus is provided for moving shielding plugs into and out of holes in concrete shielding walls in hot cells for handling radioactive materials without the use of external moving equipment. The apparatus provides a means whereby a shield plug is extracted from its hole and then swung approximately 90 degrees out of the way so that the hole may be accessed. The apparatus uses hinges to slide the plug in and out and to rotate it out of the way, the hinge apparatus also supporting the weight of the plug in all positions, with the load of the plug being transferred to a vertical wall by means of a bolting arrangement.

  8. Damage Tolerance Assessment of Friction Pull Plug Welds

    NASA Technical Reports Server (NTRS)

    McGill, Preston; Burkholder, Jonathan

    2012-01-01

    Friction stir welding is a solid state welding process developed and patented by The Welding Institute in Cambridge, England. Friction stir welding has been implemented in the aerospace industry in the fabrication of longitudinal welds in pressurized cryogenic propellant tanks. As the industry looks to implement friction stir welding in circumferential welds in pressurized cryogenic propellant tanks, techniques to close out the termination hole associated with retracting the pin tool are being evaluated. Friction pull plug welding is under development as a one means of closing out the termination hole. A friction pull plug weld placed in a friction stir weld results in a non-homogenous weld joint where the initial weld, plug weld, their respective heat affected zones and the base metal all interact. The welded joint is a composite, plastically deformed material system with a complex residual stress field. In order to address damage tolerance concerns associated with friction plug welds in safety critical structures, such as propellant tanks, nondestructive inspection and proof testing may be required to screen hardware for mission critical defects. The efficacy of the nondestructive evaluation or the proof test is based on an assessment of the critical flaw size in the test or service environments. Test data relating residual strength capability to flaw size in two aluminum alloy friction plug weld configurations is presented.

  9. SAMI Automated Plug Plate Configuration

    NASA Astrophysics Data System (ADS)

    Lorente, N. P. F.; Farrell, T.; Goodwin, M.

    2013-10-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) which uses a plug-plate to mount its 13×61-core imaging fibre bundles (hexabundles) in the optical path at the telescope's prime focus. In this paper we describe the process of determining the positions of the plug-plate holes, where plates contain three or more stacked observation configurations. The process, which up until now has involved several separate processes and has required significant manual configuration and checking, is now being automated to increase efficiency and reduce error. This is carried out by means of a thin Java controller layer which drives the configuration cycle. This layer controls the user interface and the C++ algorithm layer where the plate configuration and optimisation is carried out. Additionally, through the Aladin display package, it provides visualisation and facilitates user verification of the resulting plates.

  10. Comparison of Experimental Data and Computations Fluid Dynamics Analysis for a Three Dimensional Linear Plug Nozzle

    NASA Technical Reports Server (NTRS)

    Ruf, J. H.; Hagemann, G.; Immich, H.

    2003-01-01

    A three dimensional linear plug nozzle of area ratio 12.79 was designed by Astrium. The nozzle was tested within the German National Technology Program LION in a cold air wind tunnel by TU Dresden. The experimental hardware and test conditions are described. Experimental data was obtained for the nozzle without plug side wall fences and then with plug side wall fences. Experimental data for two nozzle pressure ratios (NPR), 116 and 45, are presented for the without fence and with fence configurations. Schlieren images of both NPR were recorded. Axial profiles of plug wall static pressures were measured at several spanwise locations and on the plug base. Detailed computational fluid dynamics (CFD) analysis was performed for these nozzle configurations by NASA MSFC. The CFD exhibits good agreement with the experimental data. A detailed comparison of the CFD results and the experimental plug wall pressure data is given for four test conditions; at both NPRs, without and with plug side wall fences. Numerical schlieren images are compared to experimental schlieren images. Nozzle thrust efficiencies are calculated from the CFD results. The CFD results are used to illustrate the plug nozzle fluid dynamics for all four test conditions. The effect of the plug side wall fences at both NPRs is emphasized.

  11. Halliburton Composite Bridge Plug Assembly

    SciTech Connect

    Starbuck, J.M.; Luttrell, C.R.; Aramayo, G.

    2005-01-15

    The overall objectives of this CRADA were to assist Halliburton in analyzing a composite bridge plug and to determine why their original design was failing in the field. In Phase 1, finite element analyses were done on the original composite slip design and several alternative designs. The composite slip was the component in the bridge plug that was failing. The finite element code ABAQUS was used for these calculations and I-DEAS was used as the pre- and post-processor in the analyses. Several different designs and materials were analyzed and recommendations were made towards improving the design. In Phase 2, the objective was to develop finite element models that would accurately represent the deformations in the entire all-composite 4-1/2' diameter bridge plug assembly. The finite element code LS-DYNA was used and the results from this effort were intended to expand Halliburton's composite design and analysis capabilities with regard to developing future composite components for downhole tools. In addition to the finite element modeling, this effort involved the utilization of micromechanics to determine the necessary composite material properties that were needed as input for finite element codes.

  12. Development of GaN-based micro chemical sensor nodes

    NASA Technical Reports Server (NTRS)

    Son, Kyung-ah; Prokopuk, Nicholas; George, Thomas; Moon, Jeong S.

    2005-01-01

    Sensors based on III-N technology are gaining significant interest due to their potential for monolithic integration of RF transceivers and light sources and the capability of high temperature operations. We are developing a GaN-based micro chemical sensor node for remote detection of chemical toxins, and present electrical responses of AlGaN/GaN HEMT (High Electron Mobility Transistor) sensors to chemical toxins as well as other common gases.

  13. Virus-Based Chemical and Biological Sensing

    PubMed Central

    Mao, Chuanbin; Liu, Aihua; Cao, Binrui

    2009-01-01

    Viruses have recently proven useful for the detection of target analytes such as explosives, proteins, bacteria, viruses, spores, and toxins with high selectivity and sensitivity. Bacteriophages (often shortened to phages), viruses that specifically infect bacteria, are currently the most studied viruses, mainly because target-specific nonlytic phages (and the peptides and proteins carried by them) can be identified by using the well-established phage display technique, and lytic phages can specifically break bacteria to release cell-specific marker molecules such as enzymes that can be assayed. In addition, phages have good chemical and thermal stability, and can be conjugated with nanomaterials and immobilized on a transducer surface in an analytical device. This Review focuses on progress made in the use of phages in chemical and biological sensors in combination with traditional analytical techniques. Recent progress in the use of virus—nanomaterial composites and other viruses in sensing applications is also high-lighted. PMID:19662666

  14. Laser-based Sensors for Chemical Detection

    SciTech Connect

    Myers, Tanya L.; Phillips, Mark C.; Taubman, Matthew S.; Bernacki, Bruce E.; Schiffern, John T.; Cannon, Bret D.

    2010-05-10

    Stand-off detection of hazardous materials ensures that the responder is located at a safe distance from the suspected source. Remote detection and identification of hazardous materials can be accomplished using a highly sensitive and portable device, at significant distances downwind from the source or the threat. Optical sensing methods, in particular infrared absorption spectroscopy combined with quantum cascade lasers (QCLs), are highly suited for the detection of chemical substances since they enable rapid detection and are amenable for autonomous operation in a compact and rugged package. This talk will discuss the sensor systems developed at Pacific Northwest National Laboratory and will discuss the progress to reduce the size and power while maintaining sensitivity to enable stand-off detection of multiple chemicals.

  15. A Rotating Plug Model of Friction Stir Welding Heat Transfer

    NASA Technical Reports Server (NTRS)

    Raghulapadu J. K.; Peddieson, J.; Buchanan, G. R.; Nunes, A. C.

    2006-01-01

    A simplified rotating plug model is employed to study the heat transfer phenomena associated with the fiction stir welding process. An approximate analytical solution is obtained based on this idealized model and used both to demonstrate the qualitative influence of process parameters on predictions and to estimate temperatures produced in typical fiction stir welding situations.

  16. Plug Load Behavioral Change Demonstration Project

    SciTech Connect

    Metzger, I.; Kandt, A.; VanGeet, O.

    2011-08-01

    This report documents the methods and results of a plug load study of the Environmental Protection Agency's Region 8 Headquarters in Denver, Colorado, conducted by the National Renewable Energy Laboratory. The study quantified the effect of mechanical and behavioral change approaches on plug load energy reduction and identified effective ways to reduce plug load energy. Load reduction approaches included automated energy management systems and behavioral change strategies.

  17. Varying nanoparticle pseudostationary phase plug length during capillary electrophoresis†

    PubMed Central

    Subramaniam, Varuni; Griffith, Lindsay; Haes, Amanda J.

    2016-01-01

    Capillary electrophoresis based separations of the hypothesized Parkinson’s disease biomarkers dopamine, epinephrine, pyrocatechol, L-3,4-dihydroxyphenylalanine (L-DOPA), glutathione, and uric acid are performed in the presence of a 1 nM 11-mercaptoundecanoic acid functionalized gold (Au@MUA) nanoparticle pseudostationary phase plug. Au@MUA nanoparticles are monitored in the capillary and remain stable in the presence of electrically-driven flow. Migration times, peak areas, and relative velocity changes (vs. no pseudostationary) are monitored upon varying (1) the Au@MUA nanoparticle pseudostationary phase plug length at a fixed separation voltage and (2) the separation voltage for a fixed Au@MUA nanoparticle pseudostationary phase plug length. For instance, the migration times of positively charged dopamine and epinephrine increase slightly as the nanoparticle pseudostationary phase plug length increases with concomitant decreases in peak areas and relative velocities as a result of attractive forces between the positively charged analytes and the negatively charged nanoparticles. Migration times for neutral pyrocatechol and slightly negative L-DOPA did not exhibit significant changes with increasing nanoparticle pseudostationary plug length; however, reduction in peak areas for these two molecules were evident and attributed to non-specific interactions (i.e. hydrogen bonding and van der Waals interactions) between the biomarkers and nanoparticles. Moreover, negatively charged uric acid and glutathione displayed progressively decreasing migration times and peak areas and as a result, increased relative velocities with increasing nanoparticle pseudostationary phase plug length. These trends are attributed to partitioning and exchanging with 11-mercaptoundecanoic acid on nanoparticle surfaces for uric acid and glutathione, respectively. Similar trends are observed when the separation voltage decreased thereby suggesting that nanoparticle-biomarker interaction

  18. Automated determination of chemical functionalisation addition routes based on magnetic susceptibility and nucleus independent chemical shifts

    NASA Astrophysics Data System (ADS)

    Van Lier, G.; Ewels, C. P.; Geerlings, P.

    2008-07-01

    We present a modified version of our previously reported meta-code SACHA, for systematic analysis of chemical addition. The code automates the generation of structures, running of quantum chemical codes, and selection of preferential isomers based on chosen selection rules. While the selection rules for the previous version were based on the total system energy, predicting purely thermodynamic addition patterns, we examine here the possibility of using other system parameters, notably magnetic susceptibility as a descriptor of global aromaticity, and nucleus independent chemical shifts (NICS) as local aromaticity descriptor.

  19. Non-plugging injection valve

    DOEpatents

    Carey, Jr., Henry S.

    1985-01-01

    A valve for injecting fluid into a conduit carrying a slurry subject to separation to form deposits capable of plugging openings into the conduit. The valve comprises a valve body that is sealed to the conduit about an aperture formed through the wall of the conduit to receive the fluid to be injected and the valve member of the valve includes a punch portion that extends through the injection aperture to the flow passage, when the valve is closed, to provide a clear channel into the conduit, when the valve is opened, through deposits which might have formed on portions of the valve adjacent the conduit.

  20. Analytical method for 44 pesticide residues in spinach using multi-plug-filtration cleanup based on multiwalled carbon nanotubes with liquid chromatography and tandem mass spectrometry detection.

    PubMed

    Qin, Yuhong; Huang, Baoyong; Zhang, Jingru; Han, Yongtao; Li, Yanjie; Zou, Nan; Yang, Jianguo; Pan, Canping

    2016-05-01

    Spinach is one of the most commonly planted vegetables worldwide. A high chlorophyll content makes spinach a complicated matrix in pesticide residue analysis. In this study, a rapid clean-up method was developed for the analysis of pesticide multi-residues in spinach followed by liquid chromatography with tandem mass spectrometry. A modified QuEChERS method with multiwalled carbon nanotubes and carbon material was adopted in the multi-Plug Filtration Cleanup procedure. This method was validated for 44 representative pesticides spiked at two concentration levels of 10 and 100 μg/kg. The pesticides of different physicochemical properties were registered on spinach in China. The recoveries were between 76 and 114% for major pesticides with relative standard deviations of less than 15%, except for quizalofop-P-ethyl, pyrimethanil, and carbendazim. Matrix-matched calibration curves were performed with the coefficients of determination higher than 0.995 for the studied pesticides for concentration levels of 10-500 μg/kg. The limits of quantitation ranged from 2 to 10 μg/kg. The developed method was successfully applied to determine pesticide residues in Chinese market spinach samples. PMID:26968118

  1. Continuous-variable quantum key distribution based on a plug-and-play dual-phase-modulated coherent-states protocol

    NASA Astrophysics Data System (ADS)

    Huang, Duan; Huang, Peng; Wang, Tao; Li, Huasheng; Zhou, Yingming; Zeng, Guihua

    2016-09-01

    We propose and experimentally demonstrate a continuous-variable quantum key distribution (CV-QKD) protocol using dual-phase-modulated coherent states. We show that the modulation scheme of our protocol works equivalently to that of the Gaussian-modulated coherent-states (GMCS) protocol, but shows better experimental feasibility in the plug-and-play configuration. Besides, it waives the necessity of propagation of a local oscillator (LO) between legitimate users and generates a real local LO for quantum measurement. Our protocol is proposed independent of the one-way GMCS QKD without sending a LO [Opt. Lett. 40, 3695 (2015), 10.1364/OL.40.003695; Phys. Rev. X 5, 041009 (2015), 10.1103/PhysRevX.5.041009; Phys. Rev. X 5, 041010 (2015), 10.1103/PhysRevX.5.041010]. In those recent works, the system stability will suffer the impact of polarization drifts induced by environmental perturbations, and two independent frequency-locked laser sources are necessary to achieve reliable coherent detection. In the proposed protocol, these previous problems can be resolved. We derive the security bounds for our protocol against collective attacks, and we also perform a proof-of-principle experiment to confirm the utility of our proposal in real-life applications. Such an efficient scheme provides a way of removing the security loopholes associated with the transmitting LO, which have been a notoriously hard problem in continuous-variable quantum communication.

  2. Friction Pull Plug and Material Configuration for Anti-Chatter Friction Pull Plug Weld

    NASA Technical Reports Server (NTRS)

    Littell, Justin Anderson (Inventor)

    2016-01-01

    A friction pull plug is provided for use in forming a plug weld in a hole in a material. The friction pull plug includes a shank and a series of three frustoconical sections. The relative sizes of the sections assure that a central one of the sections defines the initial contact point between the hole's sides. The angle defined by the central one of the sections reduces or eliminates chatter as the plug is pulled into the hole.

  3. Experimental plug and play quantum coin flipping.

    PubMed

    Pappa, Anna; Jouguet, Paul; Lawson, Thomas; Chailloux, André; Legré, Matthieu; Trinkler, Patrick; Kerenidis, Iordanis; Diamanti, Eleni

    2014-04-24

    Performing complex cryptographic tasks will be an essential element in future quantum communication networks. These tasks are based on a handful of fundamental primitives, such as coin flipping, where two distrustful parties wish to agree on a randomly generated bit. Although it is known that quantum versions of these primitives can offer information-theoretic security advantages with respect to classical protocols, a demonstration of such an advantage in a practical communication scenario has remained elusive. Here we experimentally implement a quantum coin flipping protocol that performs strictly better than classically possible over a distance suitable for communication over metropolitan area optical networks. The implementation is based on a practical plug and play system, developed by significantly enhancing a commercial quantum key distribution device. Moreover, we provide combined quantum coin flipping protocols that are almost perfectly secure against bounded adversaries. Our results offer a useful toolbox for future secure quantum communications.

  4. Experimental plug and play quantum coin flipping.

    PubMed

    Pappa, Anna; Jouguet, Paul; Lawson, Thomas; Chailloux, André; Legré, Matthieu; Trinkler, Patrick; Kerenidis, Iordanis; Diamanti, Eleni

    2014-01-01

    Performing complex cryptographic tasks will be an essential element in future quantum communication networks. These tasks are based on a handful of fundamental primitives, such as coin flipping, where two distrustful parties wish to agree on a randomly generated bit. Although it is known that quantum versions of these primitives can offer information-theoretic security advantages with respect to classical protocols, a demonstration of such an advantage in a practical communication scenario has remained elusive. Here we experimentally implement a quantum coin flipping protocol that performs strictly better than classically possible over a distance suitable for communication over metropolitan area optical networks. The implementation is based on a practical plug and play system, developed by significantly enhancing a commercial quantum key distribution device. Moreover, we provide combined quantum coin flipping protocols that are almost perfectly secure against bounded adversaries. Our results offer a useful toolbox for future secure quantum communications. PMID:24758868

  5. Construction of a Linux based chemical and biological information system.

    PubMed

    Molnár, László; Vágó, István; Fehér, András

    2003-01-01

    A chemical and biological information system with a Web-based easy-to-use interface and corresponding databases has been developed. The constructed system incorporates all chemical, numerical and textual data related to the chemical compounds, including numerical biological screen results. Users can search the database by traditional textual/numerical and/or substructure or similarity queries through the web interface. To build our chemical database management system, we utilized existing IT components such as ORACLE or Tripos SYBYL for database management and Zope application server for the web interface. We chose Linux as the main platform, however, almost every component can be used under various operating systems.

  6. Chemical compound navigator: a web-based chem-BLAST, chemical taxonomy-based search engine for browsing compounds.

    PubMed

    Prasanna, M D; Vondrasek, Jiri; Wlodawer, Alexander; Rodriguez, H; Bhat, T N

    2006-06-01

    A novel technique to annotate, query, and analyze chemical compounds has been developed and is illustrated by using the inhibitor data on HIV protease-inhibitor complexes. In this method, all chemical compounds are annotated in terms of standard chemical structural fragments. These standard fragments are defined by using criteria, such as chemical classification; structural, chemical, or functional groups; and commercial, scientific or common names or synonyms. These fragments are then organized into a data tree based on their chemical substructures. Search engines have been developed to use this data tree to enable query on inhibitors of HIV protease (http://xpdb.nist.gov/hivsdb/hivsdb.html). These search engines use a new novel technique, Chemical Block Layered Alignment of Substructure Technique (Chem-BLAST) to search on the fragments of an inhibitor to look for its chemical structural neighbors. This novel technique to annotate and query compounds lays the foundation for the use of the Semantic Web concept on chemical compounds to allow end users to group, sort, and search structural neighbors accurately and efficiently. During annotation, it enables the attachment of "meaning" (i.e., semantics) to data in a manner that far exceeds the current practice of associating "metadata" with data by creating a knowledge base (or ontology) associated with compounds. Intended users of the technique are the research community and pharmaceutical industry, for which it will provide a new tool to better identify novel chemical structural neighbors to aid drug discovery.

  7. Experimental investigation of liquid-liquid plug formation in a T-junction microchannel

    NASA Astrophysics Data System (ADS)

    Angeli, Panagiota; Chinaud, Maxime; Roumpea, Eynagelia-Panagiota; Weheliye, Weheliye; Omar. K. Matar Collaboration; Lyes Kahouadji Collaboration

    2015-11-01

    Plug formation mechanism of two immiscible liquids was studied experimentally in a 200 μm microchannel using two innovative micro Particle Image Velocimetry (μ PIV) techniques i.e. two-colour μ PIV and high speed bright field μ PIV. The aqueous phase was a water/glycerol solution whereas the organic phase was silicon oil with a range of viscosities from 5 to 155 cSt. Experiments were conducted for different fluid flow rate combinations in the T-junction inlet and it was observed that velocity profiles within the forming plugs depend on the flow rate ratios. The velocity field studies provided insight into the plug mechanism revealing that the interface curvature at the rear of the forming plug changes sign at the later stages of plug formation and accelerates the thinning of the meniscus leading to plug breakage. Results from the two-colour PIV show that the continuous phase resists the flow of the dispersed phase into the main channel at the rear of the plug meniscus and causes the change in the interface curvature. Department of Chemical Engineering South Kensington Campus Imperial College London SW7 2AZ.

  8. Chemical Mixture Risk Assessment Additivity-Based Approaches

    EPA Science Inventory

    Powerpoint presentation includes additivity-based chemical mixture risk assessment methods. Basic concepts, theory and example calculations are included. Several slides discuss the use of "common adverse outcomes" in analyzing phthalate mixtures.

  9. Modeling of Biomass Plug Development and Propagation in Porous Media

    SciTech Connect

    Stewart, Terri L.; Kim, Dong-Shik

    2004-02-01

    Biomass accumulation and evolution in porous media were simulated using a combination of biofilm evolution model and a biofilm removal model. Theses models describe biomass plug development, removal, and propagation in biological applications such as microbial enhanced oil recovery, in situ bioremediation, and bio-barrier techniques. The biofilm evolution model includes the cell growth rate and exopolymer production kinetics. The biofilm removal model was used for describing the biomass plug propagation and channel breakthrough using Bingham yield stress of biofilm, which represents the stability of biofilm against shear stress. Network model was used to describe a porous medium. The network model consists of pore body and pore bond of which the sizes were determined based on the pore size distribution of ceramic cores. The pressure drop across the network is assumed to be generated from pore bonds only, and the cell growth and biomass accumulation took place in pore bonds. The simulation results showed that the biofilm models based on Bingham yield stress predicted the biomass accumulation and channel breakthrough well. The pressure oscillation (or, permeability oscillation) was also demonstrated well indicating the process of biomass accumulation and breakthrough channel formation. In addition, the effects of cell and biofilm sucrose concentration were significant on the biomass plug development and permeability reduction rates. The modeling elucidated some deficiencies in our knowledge of the biomass yield stress that enables us to predict the stability of biomass plug against shear stress.

  10. Evaluation of commercial lithium-ion cells based on composite positive electrode for plug-in hybrid electric vehicle applications. Part I: Initial characterizations

    SciTech Connect

    Matthieu Dubarry; Cyril Truchot; Mikael Cugnet; Bor Yann Liaw; Kevin Gering; Sergiy Sazhin; David Jamison; Christopher Michelbacher

    2011-12-01

    Evaluating commercial Li-ion batteries presents some unique benefits. One of them is to use cells made from established fabrication process and form factor, such as those offered by the 18650 cylindrical configuration, to provide a common platform to investigate and understand performance deficiency and aging mechanism of target chemistry. Such an approach shall afford us to derive relevant information without influence from processing or form factor variability that may skew our understanding on cell-level issues. A series of 1.9 Ah 18650 lithium ion cells developed by a commercial source using a composite positive electrode comprising (LiMn1/3Ni1/3Co1/3O2 + LiMn2O4) is being used as a platform for the investigation of certain key issues, particularly path-dependent aging and degradation in future plug-in hybrid electric vehicle (PHEV) applications, under the US Department of Energy's Applied Battery Research (ABR) program. Here we report in Part I the initial characterizations of the cell performance and Part II some aspects of cell degradation in 2C cycle aging. The initial characterizations, including cell-to-cell variability, are essential for life cycle performance characterization in the second part of the report when cell-aging phenomena are discussed. Due to the composite nature of the positive electrode, the features (or signature) derived from the incremental capacity (IC) of the cell appear rather complex. In this work, the method to index the observed IC peaks is discussed. Being able to index the IC signature in details is critical for analyzing and identifying degradation mechanism later in the cycle aging study.

  11. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    PubMed Central

    Mitchell, Jade; Pabon, Nicolas; Collier, Zachary A.; Egeghy, Peter P.; Cohen-Hubal, Elaine; Linkov, Igor; Vallero, Daniel A.

    2013-01-01

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. PMID:23940664

  12. 21 CFR 886.4155 - Scleral plug.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... stainless steel with or without a gold, silver, or titanium coating. The special controls for the surgical grade stainless steel scleral plug (with or without a gold, silver, or titanium coating) are: (i) The... titanium coating). The special controls for scleral plugs made of other materials are: (i) The device...

  13. Plug-In Tutor Agents: Still Pluggin'

    ERIC Educational Resources Information Center

    Ritter, Steven

    2016-01-01

    "An Architecture for Plug-in Tutor Agents" (Ritter and Koedinger 1996) proposed a software architecture designed around the idea that tutors could be built as plug-ins for existing software applications. Looking back on the paper now, we can see that certain assumptions about the future of software architecture did not come to be, making…

  14. Yield Stress Effects on Mucus Plug Rupture

    NASA Astrophysics Data System (ADS)

    Hu, Yingying; Bian, Shiyao; Grotberg, John C.; Takayama, Shuichi; Grotberg, James B.

    2012-11-01

    Mucus plugs can obstruct airways, resulting in lost gas exchange and inflammation. Yield stress, one of the significant rheological properties of mucus, plays a significant role in plug rupture. We use carbopol 940 gels as mucus simulants to study dynamics of mucus plug rupture in experiments. Yield stress increases with gel concentration increasing (0.1% ~0.3%). The yield stress of the 0.2% gel is about 530 dyn/cm2, which can simulate normal mucus. A 2D PDMS channel is used to simulate a collapsed airway of the 12th generation in a human lung. Plug rupture is driven by a pressure drop of 1.6 ×104 ~ 2.0 ×104 dyn/cm2. Initial plug length varies from half to two times the half channel width. A micro-PIV technique is used to acquire velocity fields during rupture, from which wall shear stress is derived. Plug shortening velocity increases with the pressure drop, but decreases with yield stress or the initial plug length. Wall shear stress increases with yield stress, which indicates more potential damage may occur to epithelial cells when pathologic mucus has a high yield stress. Near the rupture moment, a wall shear stress peak appears at the front of the film deposited by the plug during rupture. This work is supported by NIH: HL84370 and HL85156.

  15. Polymer grouts for plugging lost circulation in geothermal wells.

    SciTech Connect

    Galbreath, D. (Green Mountain International, Waynesvile, NC); Mansure, Arthur James; Bauer, Stephen J.

    2004-12-01

    We have concluded a laboratory study to evaluate the survival potential of polymeric materials used for lost circulation plugs in geothermal wells. We learned early in the study that these materials were susceptible to hydrolysis. Through a systematic program in which many potential chemical combinations were evaluated, polymers were developed which tolerated hydrolysis for eight weeks at 500 F. The polymers also met material, handling, cost, and emplacement criteria. This screening process identified the most promising materials. A benefit of this work is that the components of the polymers developed can be mixed at the surface and pumped downhole through a single hose. Further strength testing is required to determine precisely the maximum temperature at which extrusion through fractures or voids causes failure of the lost circulation plug.

  16. Weighted voting-based consensus clustering for chemical structure databases.

    PubMed

    Saeed, Faisal; Ahmed, Ali; Shamsir, Mohd Shahir; Salim, Naomie

    2014-06-01

    The cluster-based compound selection is used in the lead identification process of drug discovery and design. Many clustering methods have been used for chemical databases, but there is no clustering method that can obtain the best results under all circumstances. However, little attention has been focused on the use of combination methods for chemical structure clustering, which is known as consensus clustering. Recently, consensus clustering has been used in many areas including bioinformatics, machine learning and information theory. This process can improve the robustness, stability, consistency and novelty of clustering. For chemical databases, different consensus clustering methods have been used including the co-association matrix-based, graph-based, hypergraph-based and voting-based methods. In this paper, a weighted cumulative voting-based aggregation algorithm (W-CVAA) was developed. The MDL Drug Data Report (MDDR) benchmark chemical dataset was used in the experiments and represented by the AlogP and ECPF_4 descriptors. The results from the clustering methods were evaluated by the ability of the clustering to separate biologically active molecules in each cluster from inactive ones using different criteria, and the effectiveness of the consensus clustering was compared to that of Ward's method, which is the current standard clustering method in chemoinformatics. This study indicated that weighted voting-based consensus clustering can overcome the limitations of the existing voting-based methods and improve the effectiveness of combining multiple clusterings of chemical structures. PMID:24830925

  17. Thin-film chemical sensors based on electron tunneling

    NASA Technical Reports Server (NTRS)

    Khanna, S. K.; Lambe, J.; Leduc, H. G.; Thakoor, A. P.

    1985-01-01

    The physical mechanisms underlying a novel chemical sensor based on electron tunneling in metal-insulator-metal (MIM) tunnel junctions were studied. Chemical sensors based on electron tunneling were shown to be sensitive to a variety of substances that include iodine, mercury, bismuth, ethylenedibromide, and ethylenedichloride. A sensitivity of 13 parts per billion of iodine dissolved in hexane was demonstrated. The physical mechanisms involved in the chemical sensitivity of these devices were determined to be the chemical alteration of the surface electronic structure of the top metal electrode in the MIM structure. In addition, electroreflectance spectroscopy (ERS) was studied as a complementary surface-sensitive technique. ERS was shown to be sensitive to both iodine and mercury. Electrolyte electroreflectance and solid-state MIM electroreflectance revealed qualitatively the same chemical response. A modified thin-film structure was also studied in which a chemically active layer was introduced at the top Metal-Insulator interface of the MIM devices. Cobalt phthalocyanine was used for the chemically active layer in this study. Devices modified in this way were shown to be sensitive to iodine and nitrogen dioxide. The chemical sensitivity of the modified structure was due to conductance changes in the active layer.

  18. Simulating the Household Plug-in Hybrid Electric Vehicle Distribution and its Electric Distribution Network Impacts

    SciTech Connect

    Cui, Xiaohui; Kim, Hoe Kyoung; Liu, Cheng; Kao, Shih-Chieh; Bhaduri, Budhendra L

    2012-01-01

    This paper presents a multi agent-based simulation framework for modeling spatial distribution of plug-in hybrid electric vehicle ownership at local residential level, discovering plug-in hybrid electric vehicle hot zones where ownership may quickly increase in the near future, and estimating the impacts of the increasing plug-in hybrid electric vehicle ownership on the local electric distribution network with different charging strategies. We use Knox County, Tennessee as a case study to highlight the simulation results of the agent-based simulation framework.

  19. Plug-in Hybrid Initiative

    SciTech Connect

    Goodman, Angie; Moore, Ray; Rowden, Tim

    2013-09-27

    Our main project objective was to implement Plug-in Electric Vehicles (PEV) and charging infrastructure into our electric distribution service territory and help reduce barriers in the process. Our research demonstrated the desire for some to be early adopters of electric vehicles and the effects lack of education plays on others. The response of early adopters was tremendous: with the initial launch of our program we had nearly 60 residential customers interested in taking part in our program. However, our program only allowed for 15 residential participants. Our program provided assistance towards purchasing a PEV and installation of Electric Vehicle Supply Equipment (EVSE). The residential participants have all come to love their PEVs and are more than enthusiastic about promoting the many benefits of driving electric.

  20. Carbon Nanotube-Based Chemical Sensors.

    PubMed

    Meyyappan, M

    2016-04-27

    The need to sense gases and vapors arises in numerous scenarios in industrial, environmental, security and medical applications. Traditionally, this activity has utilized bulky instruments to obtain both qualitative and quantitative information on the constituents of the gas mixture. It is ideal to use sensors for this purpose since they are smaller in size and less expensive; however, their performance in the field must match that of established analytical instruments in order to gain acceptance. In this regard, nanomaterials as sensing media offer advantages in sensitivity, preparation of chip-based sensors and construction of electronic nose for selective detection of analytes of interest. This article provides a review of the use of carbon nanotubes in gas and vapor sensing. PMID:26959284

  1. Friction pull plug welding: dual chamfered plate hole

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2001-01-01

    Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Early attempts with FPPW followed the matching plug/plate geometry precedence of the successful Friction Push Plug Welding program, however no defect free welds were achieved due to substantial plug necking and plug rotational stalling. The dual chamfered hole has eliminated plug rotational stalling, both upon initial plug/plate contact and during welding. Also, the necking of the heated plug metal under a tensile heating/forging load has been eliminated through the usage of the dual chamfered plate hole.

  2. Chemically modified graphene based supercapacitors for flexible and miniature devices

    NASA Astrophysics Data System (ADS)

    Ghosh, Debasis; Kim, Sang Ouk

    2015-09-01

    Rapid progress in the portable and flexible electronic devises has stimulated supercapacitor research towards the design and fabrication of high performance flexible devices. Recent research efforts for flexible supercapacitor electrode materials are highly focusing on graphene and chemically modified graphene owing to the unique properties, including large surface area, high electrical and thermal conductivity, excellent mechanical flexibility, and outstanding chemical stability. This invited review article highlights current status of the flexible electrode material research based on chemically modified graphene for supercapacitor application. A variety of electrode architectures prepared from chemically modified graphene are summarized in terms of their structural dimensions. Novel prototypes for the supercapacitor aiming at flexible miniature devices, i.e. microsupercapacitor with high energy and power density are highlighted. Future challenges relevant to graphene-based flexible supercapacitors are also suggested. [Figure not available: see fulltext.

  3. Small-Scale Spray Releases: Orifice Plugging Test Results

    SciTech Connect

    Mahoney, Lenna A.; Gauglitz, Phillip A.; Blanchard, Jeremy; Kimura, Marcia L.; Kurath, Dean E.

    2012-09-01

    One of the events postulated in the hazard analysis at the Waste Treatment and Immobilization Plant (WTP) and other U.S. Department of Energy (DOE) nuclear facilities, is a breach in process piping that produces aerosols with droplet sizes in the respirable range. The current approach for predicting the size and concentration of aerosols produced in a spray leak involves extrapolating from correlations published in the literature. These correlations are based on results obtained from small engineered spray nozzles using pure liquids with Newtonian fluid behavior. The narrow ranges of physical properties on which the correlations are based do not cover the wide range of slurries and viscous materials present in the WTP and across processing facilities in the DOE complex. Two key technical areas were identified where testing results were needed to improve the technical basis by reducing the uncertainty introduced by extrapolating existing literature results. The first technical need was to quantify the role of slurry particles in small breaches in which the slurry particles may plug and result in substantially reduced, or even negligible, respirable fraction formed by high pressure sprays. The second technical need was to determine the aerosol droplet size distribution and volume from prototypic breaches and fluids, specifically including sprays from larger breaches with slurries where data from the literature are largely absent. To address these technical areas, small- and large-scale test stands were constructed and operated with simulants to determine the aerosol release fractions and aerosol generation rates from a range of breach sizes and geometries. The properties of the simulants represented the range of properties expected in the WTP process streams and included water, sodium salt solutions, slurries containing boehmite or gibbsite, and a hazardous chemical simulant. The effect of anti-foam agents (AFA) was assessed with most of the simulants. Orifices

  4. Efficient exploration of chemical space by fragment-based screening.

    PubMed

    Hall, Richard J; Mortenson, Paul N; Murray, Christopher W

    2014-01-01

    Screening methods seek to sample a vast chemical space in order to identify starting points for further chemical optimisation. Fragment based drug discovery exploits the superior sampling of chemical space that can be achieved when the molecular weight is restricted. Here we show that commercially available fragment space is still relatively poorly sampled and argue for highly sensitive screening methods to allow the detection of smaller fragments. We analyse the properties of our fragment library versus the properties of X-ray hits derived from the library. We particularly consider properties related to the degree of planarity of the fragments.

  5. Plasmonics Based Harsh Environment Compatible Chemical Sensors

    SciTech Connect

    Michael Carpenter

    2012-01-15

    Au-YSZ, Au-TiO{sub 2} and Au-CeO{sub 2} nanocomposite films have been investigated as a potential sensing element for high-temperature plasmonic sensing of H{sub 2}, CO, and NO{sub 2} in an oxygen containing environment. The Au-YSZ and Au-TiO{sub 2} films were deposited using PVD methods, while the CeO{sub 2} thin film was deposited by molecular beam epitaxy (MBE) and Au was implanted into the as-grown film at an elevated temperature followed by high temperature annealing to form well-defined Au nanoclusters. Each of the films were characterized by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). For the gas sensing experiments, separate exposures to varying concentrations of H{sub 2}, CO, and NO{sub 2} were performed at a temperature of 500°C in oxygen backgrounds of 5.0, 10, and ~21% O{sub 2}. Changes in the localized surface plasmon resonance (LSPR) absorption peak were monitored during gas exposures and are believed to be the result of oxidation-reduction processes that fill or create oxygen vacancies in the respective metal oxides. This process affects the LSPR peak position either by charge exchange with the Au nanoparticles or by changes in the dielectric constant surrounding the particles. Hyperspectral multivariate analysis was used to gauge the inherent selectivity of the film between the separate analytes. From principal component analysis (PCA), unique and identifiable responses were seen for each of the analytes. Linear discriminant analysis (LDA) was also used on the Au-CeO{sub 2} results and showed separation between analytes as well as trends in gas concentration. Results indicate that each of the films are is selective towards O{sub 2}, H{sub 2}, CO, and NO{sub 2} in separate exposures. However, when the films were analyzed in a sensor array based experiment, ie simultaneous exposures to the target gases, PCA analysis of the combined response showed an even greater selective character towards the target gases. Combined

  6. Mitigation of Syngas Cooler Plugging and Fouling

    SciTech Connect

    Bockelie, Michael J.

    2015-06-29

    understanding of deposit formation mechanisms; • performing Techno-Economic-Analysis for a representative IGCC plant to investigate the impact on plant economics, in particular the impacts on the Cost of Electricity (COE), due to plant shutdowns caused by syngas cooler plugging and fouling and potential benefits to plant economics of developing strategies to mitigate syngas cooler fouling; and • performing modeling and pilot scale tests to investigate the potential benefits of using a sorbent (fuel additive) to capture the vaporized metals that result in syngas cooler fouling. All project milestones for BP 1 and BP 2 were achieved. DOE was provided a briefing on our accomplishments in BP1 and BP2 and our proposed plans for Budget Period 3 (BP 3). Based on our research the mitigation technology selected to investigate in BP 3 was the use of a sorbent that can be injected into the gasifier with the fuel slurry to capture vaporized metals that lead to the deposit formation in the syngas cooler. The work effort proposed for BP 3 would have focused on addressing concerns raised by gasification industry personnel for the impacts on gasifier performance of sorbent injection, so that at the end of BP 3 the use of sorbent injection would be at “pre-commercial” stage and ready for use in a Field Demonstration that could be funded by industry or DOE. A Budget Continuation Application (BCA) was submitted to obtain funding for BP3 DOE but DOE chose to not fund the proposed BP3 effort.

  7. Learning of Chemical Equilibrium through Modelling-Based Teaching

    ERIC Educational Resources Information Center

    Maia, Poliana Flavia; Justi, Rosaria

    2009-01-01

    This paper presents and discusses students' learning process of chemical equilibrium from a modelling-based approach developed from the use of the "Model of Modelling" diagram. The investigation was conducted in a regular classroom (students 14-15 years old) and aimed at discussing how modelling-based teaching can contribute to students learning…

  8. Polysaccharides and bacterial plugging. Final report, 1992--1993

    SciTech Connect

    Fogler, H.S.

    1995-02-01

    In situ core plugging experiments and transport experiments, using the model bacteria Leuconostoc m., have been conducted. Results demonstrated that cellular polysaccharide production increases cell distribution in porous media and caused an overall decrease in media permeability. Further, a parallel core plugging experiment was conducted and showed the feasibility of this system to divert injection fluid from high permeability zones into low permeability zones within porous media as is needed for profile modification. To implement this type of application, however, controlled placement of cells and rates of polymer production are needed. Therefore, kinetic studies were performed. A kinetic model was subsequently developed for Leuconostoc m. bacteria. This model is based on data generated from batch growth experiments and allows for the prediction of saccharide utilization, cell generation, and dextran production. These predictions can be used to develop injection strategies for field implementation. Transport and in situ growth micromodel experiments have shown how dextran allow cells to remain as clusters after cell division which enhanced cell capture and retention in porous media. Additional Damkohler experiments have been performed to determine the effects of the nutrient injection rate and nutrient concentration on the rate of porous media plugging. As shown experimentally and as predicted by a model for in situ growth, an increase in nutrient concentration and/or its injection rate will result in a faster rate of porous media plugging. Through continuum model simulations, it has been shown that the initial cell profiles play a key role on the core plugging rate. Controlling the location of the inoculating cells is thus another key factor in using bacteria for profile modification.

  9. Friction Pull Plug Welding in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Brooke, Shane A.; Bradford, Vann

    2012-01-01

    NASA's Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for the Space Shuttle fs External Tank. FPPW was easily selected as the primary weld process used to close out the termination hole on the Constellation Program's ARES I Upper Stage circumferential Self-Reacting Friction Stir Welds (SR-FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR-FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process's limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

  10. Friction Pull Plug Welding in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Brooke, Shane A.; Bradford, Vann; Burkholder, Jonathon

    2011-01-01

    NASA fs Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for External Tank. FPPW was easily selected as the primary process used to close out the termination hole on the Constellation Program fs ARES I Upper Stage circumferential Self ] Reacting Friction Stir Welds (SR ]FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR ]FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process fs limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

  11. Plug cementing: Horizontal to vertical conditions

    SciTech Connect

    Calvert, D.G.; Heathman, J.F.; Griffith, J.E.

    1995-12-31

    This paper presents an in-depth study of cement plug placement that was conducted with large-scale models for the improvement of plug cementing practices and plug integrity. Common hole and workstring geometries were examined with various rheology and density ratios between the drilling fluid and cement. The critical conditions dictating the difference between success and failure for various wellbore angles and conditions were explored, and the mechanisms controlling slurry movement before and after placement are now better understood. An understanding of these mechanisms allows the engineer to better tailor a design to specific hole conditions. Controversial concepts regarding plug-setting practices have been examined and resolved. The cumulative effects of density, rheology, and hole angle are major factors affecting plug success. While the Boycott effect and an extrusion effect were observed to be predominant in inclined wellbores, a spiraling or {open_quotes}roping{close_quotes} effect controls slurry movement in vertical wellbores. Ultimate success of a cement plug can be obtained if allowances are made for these effects in the job design, provided all other previously published recommended placement practices are followed. Results of this work can be applied to many sidetracking and plug-to-abandon operations. Additionally, the understanding of the fluid movement (creep) mechanisms holds potential for use in primary and remedial cementing work, and in controlling the placement of noncementitious fluids in the wellbore.

  12. Standard metrics for a plug-and-play tracker

    NASA Astrophysics Data System (ADS)

    Antonisse, Jim; Young, Darrell

    2012-06-01

    The Motion Imagery Standards Board (MISB) has previously established a metadata "micro-architecture" for standards-based tracking. The intent of this work is to facilitate both the collaborative development of competent tracking systems, and the potentially distributed and dispersed execution of tracker system components in real-world execution environments. The approach standardizes a set of five quasi-sequential modules in image-based tracking. However, in order to make the plug-and-play architecture truly useful we need metrics associated with each module (so that, for instance, a researcher who "plugs in" a new component can ascertain whether he/she did better or worse with the component). This paper proposes the choice of a new, unifying set of metrics based on an informationtheoretic approach to tracking, which the MISB is nominating as DoD/IC/NATO standards.

  13. Simulation on friction taper plug welding of AA6063-20Gr metal matrix composite

    NASA Astrophysics Data System (ADS)

    Hynes, N. Rajesh Jesudoss; Nithin, Abeyram M.

    2016-05-01

    Friction taper plug welding a variant of friction welding is useful in welding of similar and dissimilar materials. It could be used for joining of composites to metals in sophisticated aerospace applications. In the present work numerical simulation of friction taper plug welding process is carried out using finite element based software. Graphite reinforced AA6063 is modelled using the software ANSYS 15.0 and temperature distribution is predicted. Effect of friction time on temperature distribution is numerically investigated. When the friction time is increased to 30 seconds, the tapered part of plug gets detached and fills the hole in the AA6063 plate perfectly.

  14. Lubricant base stock potential of chemically modified vegetable oils.

    PubMed

    Erhan, Sevim Z; Sharma, Brajendra K; Liu, Zengshe; Adhvaryu, Atanu

    2008-10-01

    The environment must be protected against pollution caused by lubricants based on petroleum oils. The pollution problem is so severe that approximately 50% of all lubricants sold worldwide end up in the environment via volatility, spills, or total loss applications. This threat to the environment can be avoided by either preventing undesirable losses, reclaiming and recycling mineral oil lubricants, or using environmentally friendly lubricants. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates as base fluids in environment friendly lubricants. Lubricants based on vegetable oils display excellent tribological properties, high viscosity indices, and flash points. To compete with mineral-oil-based lubricants, some of their inherent disadvantages, such as poor oxidation and low-temperature stability, must be corrected. One way to address these problems is chemical modification of vegetable oils at the sites of unsaturation. After a one-step chemical modification, the chemically modified soybean oil derivatives were studied for thermo-oxidative stability using pressurized differential scanning calorimetry and a thin-film micro-oxidation test, low-temperature fluid properties using pour-point measurements, and friction-wear properties using four-ball and ball-on-disk configurations. The lubricants formulated with chemically modified soybean oil derivatives exhibit superior low-temperature flow properties, improved thermo-oxidative stability, and better friction and wear properties. The chemically modified soybean oil derivatives having diester substitution at the sites of unsaturation have potential in the formulation of industrial lubricants.

  15. Controlled evaporation of superfluid helium in a porous plug phase separator

    NASA Astrophysics Data System (ADS)

    Lages, Christopher R.

    1998-12-01

    New cryogenic propulsion system technology to be used on the Relativity Mission (GP-B) and MiniSTEP satellites requires the porous plug to operate in a dynamic environment with variable vent line impedance due to the use of the evaporated vapor as the propellant for the attitude and translational control system (ATCS). Ranges of ATCS thrust requirements for the satellite missions translate into a range of evaporative mass flow which must be provided by the porous plug. The mass flow profile of a porous plug defines its evaporative mass flow behavior during operation. As a porous plug can exhibit an evaporative mass flow profile reducing the overall performance of a cryogenic propulsion system, selection of a flight plug with the correct mass flow profile is of critical importance in system design. Currently, approximate but still incomplete theory in conjunction with experimental iteration provides a means for selecting a porous plug with repeatable flow behavior adequate for flight. An alternate technique of porous plug operation based on the ideal behavior and thermomechanical effect of superfluid helium provides the required mass flow rates, maintains the performance of the cryogenic propulsion system, and reduces iterative testing for flight porous plugs. Heating of the downstream surface of a porous plug while controlling the vent line impedance augments the mass flow through the plug. This technique greatly increases the operational range of the plug while providing the ability to maintain thermodynamic conditions at its downstream surface. Thus, a porous plug can meet extended ranges of mass flow and simultaneously maintain the highest performance of the propulsion system. In this thesis, we have extended this technique by performing experiments with controlled heating of the downstream surface of a porous plug while operating it in its repeatable flow regime. Our results demonstrate the evaporative mass flow rate can be increased in the repeatable flow

  16. Porous plug for Gravity Probe B

    NASA Astrophysics Data System (ADS)

    Wang, Suwen; Everitt, C. W. Francis; Frank, David J.; Lipa, John A.; Muhlfelder, Barry F.

    2015-11-01

    The confinement of superfluid helium for a Dewar in space poses a unique challenge due to its propensity to minimize thermal gradients by essentially viscous-free counterflow. This poses the risk of losing liquid through a vent pipe, reducing the efficiency of the cooling process. To confine the liquid helium in the Gravity Probe B (GP-B) flight Dewar, a porous plug technique was invented at Stanford University. Here, we review the history of the porous plug and its development, and describe the physics underlying its operation. We summarize a few missions that employed porous plugs, some of which preceded the launch of GP-B. The design, manufacture and flight performance of the GP-B plug are described, and its use resulted in the successful operation of the 2441 l flight Dewar on-orbit for 17.3 months.

  17. 40 CFR 146.92 - Injection well plugging.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Section 146.92 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... of each plug, including the elevation of the top and bottom of each plug; (5) The type, grade, and...; and (6) The method of placement of the plugs. (c) Notice of intent to plug. The owner or operator...

  18. 40 CFR 146.92 - Injection well plugging.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Section 146.92 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... of each plug, including the elevation of the top and bottom of each plug; (5) The type, grade, and...; and (6) The method of placement of the plugs. (c) Notice of intent to plug. The owner or operator...

  19. 40 CFR 146.92 - Injection well plugging.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Section 146.92 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... of each plug, including the elevation of the top and bottom of each plug; (5) The type, grade, and...; and (6) The method of placement of the plugs. (c) Notice of intent to plug. The owner or operator...

  20. Femoral Bone Plug in Total Knee Replacement.

    PubMed

    Vulcano, Ettore; Regazzola, Gianmarco M V; Murena, Luigi; Ronga, Mario; Cherubino, Paolo; Surace, Michele F

    2015-10-01

    The intramedullary alignment guides used in total knee replacement disrupt the intramedullary vessels, resulting in greater postoperative blood loss. The use of an autologous bone plug to seal the intramedullary femoral canal has been shown to be effective in reducing postoperative bleeding. The authors present a simple technique to create a bone plug from the anterior chamfer femoral cut to perfectly seal the intramedullary canal of the femur. PMID:26488774

  1. Hybrid and Plug-in Electric Vehicles

    SciTech Connect

    2014-05-20

    Hybrid and plug-in electric vehicles use electricity either as their primary fuel or to improve the efficiency of conventional vehicle designs. This new generation of vehicles, often called electric drive vehicles, can be divided into three categories: hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles(PHEVs), and all-electric vehicles (EVs). Together, they have great potential to reduce U.S. petroleum use.

  2. Chemical Information in Scirus and BASE (Bielefeld Academic Search Engine)

    ERIC Educational Resources Information Center

    Bendig, Regina B.

    2009-01-01

    The author sought to determine to what extent the two search engines, Scirus and BASE (Bielefeld Academic Search Engines), would be useful to first-year university students as the first point of searching for chemical information. Five topics were searched and the first ten records of each search result were evaluated with regard to the type of…

  3. Preliminary geochemical and physical testing of materials for plugging of man-made accesses to a repository in basalt

    SciTech Connect

    Taylor, C.L.; Anttonen, G.J.; O'Rourke, J.E.; Allirot, D.

    1980-04-01

    The available data on environmental conditions (both natural and man-made) at the Hanford Site are sufficient for preconceptual plug system design. Results of the geochemical testing program indicate that preferred candidate plug materials are chemically nonreactive during laboratory tests that simulated some of the expected environmental conditions. Agitated, crushed-basalt samples and mixtures containing basalt were found to be self-cementing under the hydrothermal conditions. Materials considered most suitable for consideration in future test programs and preconceptual plug design are mixtures of natural materials (basalt, clay, glaciofluvial sand, gravel, and zeolite) and processed natural materials (portland cement Type V and grouts plus additives).

  4. Progress in chemical luminescence-based biosensors: A critical review.

    PubMed

    Roda, Aldo; Mirasoli, Mara; Michelini, Elisa; Di Fusco, Massimo; Zangheri, Martina; Cevenini, Luca; Roda, Barbara; Simoni, Patrizia

    2016-02-15

    Biosensors are a very active research field. They have the potential to lead to low-cost, rapid, sensitive, reproducible, and miniaturized bioanalytical devices, which exploit the high binding avidity and selectivity of biospecific binding molecules together with highly sensitive detection principles. Of the optical biosensors, those based on chemical luminescence detection (including chemiluminescence, bioluminescence, electrogenerated chemiluminescence, and thermochemiluminescence) are particularly attractive, due to their high-to-signal ratio and the simplicity of the required measurement equipment. Several biosensors based on chemical luminescence have been described for quantitative, and in some cases multiplex, analysis of organic molecules (such as hormones, drugs, pollutants), proteins, and nucleic acids. These exploit a variety of miniaturized analytical formats, such as microfluidics, microarrays, paper-based analytical devices, and whole-cell biosensors. Nevertheless, despite the high analytical performances described in the literature, the field of chemical luminescence biosensors has yet to demonstrate commercial success. This review presents the main recent advances in the field and discusses the approaches, challenges, and open issues, with the aim of stimulating a broader interest in developing chemical luminescence biosensors and improving their commercial exploitation.

  5. [Development of anti-HIV agents based on chemical biology].

    PubMed

    Tamamura, Hirokazu

    2012-01-01

    Recently, highly active anti-retroviral therapy (HAART), which involves a combinational use of reverse transcriptase inhibitors and HIV protease inhibitors, has brought us a great success in the clinical treatment of AIDS patients. However, HAART has several serious clinical problems. These drawbacks encouraged us to find novel drugs and increase repertoires of anti-HIV agents with various action mechanisms. The recent disclosing of the dynamic supramolecular mechanism in HIV-entry has provided potentials to find a new type of drugs. To date, we have synthesized HIV-entry inhibitors, especially coreceptor CXCR4 antagonists. In addition, CD4 mimics in consideration of synergic effects with other entry inhibitors or neutralizing antibodies have been developed. The development of the above anti-HIV agents is based on the concept of reverse chemical genomics, in which target molecules are fixed. On the other hand, based on the concept of forward chemical genomics, in which active compounds are searched according to the screening of random libraries, effective peptide leads such as integrase inhibitors derived from fragment peptides of HIV-1 Vpr have been discovered. As such, from a point of view on chemical biology, anti-HIV leads have been found utilizing reverse and forward chemical genomics. Furthermore, antibody-based therapy or AIDS vaccine is still thought to be a promising treatment. Thus, peptidic antigen molecules based on artificial remodeling of the dynamic structures of a surface protein gp41 in HIV fusion have been developed. The present chemical biology approaches would be essential for discovery of anti-HIV agents in consideration of cocktail therapy of AIDS.

  6. Chemical interaction matrix between reagents in a Purex based process

    SciTech Connect

    Brahman, R.K.; Hennessy, W.P.; Paviet-Hartmann, P.

    2008-07-01

    The United States Department of Energy (DOE) is the responsible entity for the disposal of the United States excess weapons grade plutonium. DOE selected a PUREX-based process to convert plutonium to low-enriched mixed oxide fuel for use in commercial nuclear power plants. To initiate this process in the United States, a Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF) is under construction and will be operated by Shaw AREVA MOX Services at the Savannah River Site. This facility will be licensed and regulated by the U.S. Nuclear Regulatory Commission (NRC). A PUREX process, similar to the one used at La Hague, France, will purify plutonium feedstock through solvent extraction. MFFF employs two major process operations to manufacture MOX fuel assemblies: (1) the Aqueous Polishing (AP) process to remove gallium and other impurities from plutonium feedstock and (2) the MOX fuel fabrication process (MP), which processes the oxides into pellets and manufactures the MOX fuel assemblies. The AP process consists of three major steps, dissolution, purification, and conversion, and is the center of the primary chemical processing. A study of process hazards controls has been initiated that will provide knowledge and protection against the chemical risks associated from mixing of reagents over the life time of the process. This paper presents a comprehensive chemical interaction matrix evaluation for the reagents used in the PUREX-based process. Chemical interaction matrix supplements the process conditions by providing a checklist of any potential inadvertent chemical reactions that may take place. It also identifies the chemical compatibility/incompatibility of the reagents if mixed by failure of operations or equipment within the process itself or mixed inadvertently by a technician in the laboratories. (aut0010ho.

  7. Microstructural and Chemical Rejuvenation of a Ni-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Yao, Zhiqi; Degnan, Craig C.; Jepson, Mark A. E.; Thomson, Rachel C.

    2016-10-01

    The microstructural evolution of the Ni-based superalloy CMSX-4 including the change in gamma prime morphology, size, and distribution after high-temperature degradation and subsequent rejuvenation heat treatments has been examined using field emission gun scanning electron microscopy and transmission electron microscopy. In this paper, it is shown that there are significant differences in the size of the `channels' between gamma prime particles, the degree of rafting, and the size of tertiary gamma prime particles in each of the different microstructural conditions studied. Chemical analysis has been carried out to compare rejuvenated and pre-service samples after the same subsequent degradation procedure. The results indicate that although the microstructures of pre-service and rejuvenated samples are similar, chemical differences are more pronounced in the rejuvenated samples, suggesting that chemical segregation from partitioning of the elements was not completely eliminated through the applied rejuvenation heat treatment. A number of modified rejuvenation heat treatment trials were carried out to reduce the chemical segregation prior to creep testing. The creep test results suggest that chemical segregation has an immeasurable influence on the short-term mechanical properties under the test conditions used here, indicating that further work is required to fully understand the suitability of specific rejuvenation heat treatments and their role in the extension of component life in power plant applications.

  8. Interdependent chemical-electrochemical steps in retrometabolism-based drug and safer chemical design.

    PubMed

    Tókés, B; Suciu, G; Nagy, G

    2002-02-01

    An extension of the retrometabolic based drug (chemical) design concept, specifically the soft drug approach, to the family of nitrone compounds is presented. Nitrones oppose oxidative challenges by virtue of their ability to very rapidly trap free radical species that are more stable and biochemically less harmful than the original molecular fragments. Moreover, the spin adducts may undergo further transformations including reaction with a second radical and decomposition (hydrolysis) to hydroxylamines and carbonyl compounds. Nitrones and their spin adducts may generate nitric oxide in vivo, which, like nitrones themselves, exerts a number of diverse activities in phylogenetically distant species as well as opposing effects in related biological systems. It was described as a major messenger in the cardiovascular, immune, and nervous systems, in which it plays regulatory, signaling, cytoprotective, and cytotoxic effects. Nitrones play an important role in the synthesis of drugs belonging to chemically and pharmacologically very different classes. A combined chemical-electrochemical synthesis of nitrones has been elaborated. These compounds may be obtained from aldehydes or ketones and N-substituted hydroxylamines. These reactions were performed directly, in situ in the electrochemical cell, where phenylhydroxylamine obtained by electroreduction of nitrobenzene derivatives reacts with the carbonyl compound introduced in the cell. The kinetic and thermodynamic parameters of the processes were determined by analyzing the adequate polarographic curves. Differences between purely chemical and mixed chemical-electrochemical methods are discussed. Analysis of the experimental data permits optimization of the investigated process from a preparative point of view. Effects of structural factors were systematically evaluated. The proposed method may be useful for combinatorial chemistry as well.

  9. Amber Plug-In for Protein Shop

    2004-05-10

    The Amber Plug-in for ProteinShop has two main components: an AmberEngine library to compute the protein energy models, and a module to solve the energy minimization problem using an optimization algorithm in the OPTI-+ library. Together, these components allow the visualization of the protein folding process in ProteinShop. AmberEngine is a object-oriented library to compute molecular energies based on the Amber model. The main class is called ProteinEnergy. Its main interface methods are (1) "init"more » to initialize internal variables needed to compute the energy. (2) "eval" to evaluate the total energy given a vector of coordinates. Additional methods allow the user to evaluate the individual components of the energy model (bond, angle, dihedral, non-bonded-1-4, and non-bonded energies) and to obtain the energy of each individual atom. The Amber Engine library source code includes examples and test routines that illustrate the use of the library in stand alone programs. The energy minimization module uses the AmberEngine library and the nonlinear optimization library OPT++. OPT++ is open source software available under the GNU Lesser General Public License. The minimization module currently makes use of the LBFGS optimization algorithm in OPT++ to perform the energy minimization. Future releases may give the user a choice of other algorithms available in OPT++.« less

  10. Aeroacoustics of a porous plug jet noise suppressor

    NASA Technical Reports Server (NTRS)

    Dosanjh, D. S.

    1981-01-01

    The aeroacoustics of a porous plug jet noise suppressor was investigated. The predicted flow features of isentropic plug nozzles for different pressure ratios or exit flow Mach numbers, throat areas, ratios of the plug to annular nozzle radii, mass flow rates and the available run times possible with the existing compressed air supply system, are compiled. The dimensions and the coordinates of the contour of typical isentropic external expansion plugs with different exit flow Mach numbers are listed. Design details of the experimental facility and the plug nozzle selected for experimental aeroacoustic studies are reported. The analytical flow prediction by method of characteristics of a conical porous plug nozzles is initiated. The role of the shape, size, and porosity of the plug surface in achieving over a perforated conical plug a nearly isentropic shockfree supersonic flow field which is closely similar to the flow field of a contoured isentropic plug nozzle is examined.

  11. Nozzle dam having a unitary plug

    DOEpatents

    Veronesi, Luciano; Wepfer, Robert M.

    1992-01-01

    Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket.

  12. Nozzle dam having a unitary plug

    DOEpatents

    Veronesi, L.; Wepfer, R.M.

    1992-12-15

    Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator is disclosed. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket. 16 figs.

  13. Liquid Microjunction Surface Sampling Probe Fluid Dynamics: Characterization and Application of an Analyte Plug Formation Operational Mode

    SciTech Connect

    ElNaggar, Mariam S; Van Berkel, Gary J

    2011-01-01

    The recently discovered sample plug formation and injection operational mode of a continuous flow, coaxial tube geometry, liquid microjunction surface sampling probe (LMJ-SSP) (J. Am. Soc. Mass Spectrom, 2011) was further characterized and applied for concentration and mixing of analyte extracted from multiple areas on a surface and for nanoliter-scale chemical reactions of sampled material. A transparent LMJ-SSP was constructed and colored analytes were used so that the surface sampling process, plug formation, and the chemical reactions could be visually monitored at the sampling end of the probe before being analyzed by mass spectrometry of the injected sample plug. Injection plug peak widths were consistent for plug hold times as long as the 8 minute maximum attempted (RSD below 1.5%). Furthermore, integrated injection peak signals were not significantly different for the range of hold times investigated. The ability to extract and completely mix individual samples within a fixed volume at the sampling end of the probe was demonstrated and a linear mass spectral response to the number of equivalent analyte spots sampled was observed. Using the color and mass changing chemical reduction of the redox dye 2,6-dichlorophenol-indophenol with ascorbic acid, the ability to sample, concentrate, and efficiently run reactions within the same plug volume within the probe was demonstrated.

  14. Liquid Microjunction Surface Sampling Probe Fluid Dynamics: Characterization and Application of an Analyte Plug Formation Operational Mode

    NASA Astrophysics Data System (ADS)

    Elnaggar, Mariam S.; van Berkel, Gary J.

    2011-10-01

    The recently discovered sample plug formation and injection operational mode of a continuous flow, coaxial tube geometry, liquid microjunction surface sampling probe (LMJ-SSP) was further characterized and applied for concentration and mixing of analyte extracted from multiple areas on a surface and for nanoliter-scale chemical reactions of sampled material. A transparent LMJ-SSP was constructed and colored analytes were used so that the surface sampling process, plug formation, and the chemical reactions could be visually monitored at the sampling end of the probe before being analyzed by mass spectrometry of the injected sample plug. Injection plug peak widths were consistent for plug hold times as long as the 8 min maximum attempted (RSD below 1.5%). Furthermore, integrated injection peak signals were not significantly different for the range of hold times investigated. The ability to extract and completely mix individual samples within a fixed volume at the sampling end of the probe was demonstrated and a linear mass spectral response to the number of equivalent analyte spots sampled was observed. Using the color and mass changing chemical reduction of the redox dye 2,6-dichlorophenol-indophenol with ascorbic acid, the ability to sample, concentrate, and efficiently run reactions within the same plug volume within the probe was demonstrated.

  15. Silicon-based sleeve devices for chemical reactions

    DOEpatents

    Northrup, M. Allen; Mariella, Jr., Raymond P.; Carrano, Anthony V.; Balch, Joseph W.

    1996-01-01

    A silicon-based sleeve type chemical reaction chamber that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis.

  16. Silicon-based sleeve devices for chemical reactions

    DOEpatents

    Northrup, M.A.; Mariella, R.P. Jr.; Carrano, A.V.; Balch, J.W.

    1996-12-31

    A silicon-based sleeve type chemical reaction chamber is described that combines heaters, such as doped polysilicon for heating, and bulk silicon for convection cooling. The reaction chamber combines a critical ratio of silicon and silicon nitride to the volume of material to be heated (e.g., a liquid) in order to provide uniform heating, yet low power requirements. The reaction chamber will also allow the introduction of a secondary tube (e.g., plastic) into the reaction sleeve that contains the reaction mixture thereby alleviating any potential materials incompatibility issues. The reaction chamber may be utilized in any chemical reaction system for synthesis or processing of organic, inorganic, or biochemical reactions, such as the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction, which are examples of a synthetic, thermal-cycling-based reaction. The reaction chamber may also be used in synthesis instruments, particularly those for DNA amplification and synthesis. 32 figs.

  17. Agent-Based Chemical Plume Tracing Using Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Zarzhitsky, Dimitri; Spears, Diana; Thayer, David; Spears, William

    2004-01-01

    This paper presents a rigorous evaluation of a novel, distributed chemical plume tracing algorithm. The algorithm is a combination of the best aspects of the two most popular predecessors for this task. Furthermore, it is based on solid, formal principles from the field of fluid mechanics. The algorithm is applied by a network of mobile sensing agents (e.g., robots or micro-air vehicles) that sense the ambient fluid velocity and chemical concentration, and calculate derivatives. The algorithm drives the robotic network to the source of the toxic plume, where measures can be taken to disable the source emitter. This work is part of a much larger effort in research and development of a physics-based approach to developing networks of mobile sensing agents for monitoring, tracking, reporting and responding to hazardous conditions.

  18. Automation of static and dynamic non-dispersive liquid phase microextraction. Part 1: Approaches based on extractant drop-, plug-, film- and microflow-formation.

    PubMed

    Alexovič, Michal; Horstkotte, Burkhard; Solich, Petr; Sabo, Ján

    2016-02-01

    Simplicity, effectiveness, swiftness, and environmental friendliness - these are the typical requirements for the state of the art development of green analytical techniques. Liquid phase microextraction (LPME) stands for a family of elegant sample pretreatment and analyte preconcentration techniques preserving these principles in numerous applications. By using only fractions of solvent and sample compared to classical liquid-liquid extraction, the extraction kinetics, the preconcentration factor, and the cost efficiency can be increased. Moreover, significant improvements can be made by automation, which is still a hot topic in analytical chemistry. This review surveys comprehensively and in two parts the developments of automation of non-dispersive LPME methodologies performed in static and dynamic modes. Their advantages and limitations and the reported analytical performances are discussed and put into perspective with the corresponding manual procedures. The automation strategies, techniques, and their operation advantages as well as their potentials are further described and discussed. In this first part, an introduction to LPME and their static and dynamic operation modes as well as their automation methodologies is given. The LPME techniques are classified according to the different approaches of protection of the extraction solvent using either a tip-like (needle/tube/rod) support (drop-based approaches), a wall support (film-based approaches), or microfluidic devices. In the second part, the LPME techniques based on porous supports for the extraction solvent such as membranes and porous media are overviewed. An outlook on future demands and perspectives in this promising area of analytical chemistry is finally given.

  19. Chemical monitors based on Surface-Enhanced Raman Scattering (SERS)

    SciTech Connect

    Vo-Dinh, T.; Alarie, J.P.; Sutherland, W.S.; Stokes, D.L.; Miller, G.H.

    1992-12-31

    This paper presents an overview of the development of chemical monitors using the Surface-Enhanced Raman Scattering (SERS) technique. The SERS effect is based on recent experimental observations, which have indicated enhancement of the Raman scattering efficiency by factors up to 10{sup 8} when a compound is adsorbed on rough metallic surfaces having submicron protrusions. The focus of our research efforts is on the development of SERS-active sensors and instrumentation capable of field analysis and remote sensing.

  20. Automation of static and dynamic non-dispersive liquid phase microextraction. Part 1: Approaches based on extractant drop-, plug-, film- and microflow-formation.

    PubMed

    Alexovič, Michal; Horstkotte, Burkhard; Solich, Petr; Sabo, Ján

    2016-02-01

    Simplicity, effectiveness, swiftness, and environmental friendliness - these are the typical requirements for the state of the art development of green analytical techniques. Liquid phase microextraction (LPME) stands for a family of elegant sample pretreatment and analyte preconcentration techniques preserving these principles in numerous applications. By using only fractions of solvent and sample compared to classical liquid-liquid extraction, the extraction kinetics, the preconcentration factor, and the cost efficiency can be increased. Moreover, significant improvements can be made by automation, which is still a hot topic in analytical chemistry. This review surveys comprehensively and in two parts the developments of automation of non-dispersive LPME methodologies performed in static and dynamic modes. Their advantages and limitations and the reported analytical performances are discussed and put into perspective with the corresponding manual procedures. The automation strategies, techniques, and their operation advantages as well as their potentials are further described and discussed. In this first part, an introduction to LPME and their static and dynamic operation modes as well as their automation methodologies is given. The LPME techniques are classified according to the different approaches of protection of the extraction solvent using either a tip-like (needle/tube/rod) support (drop-based approaches), a wall support (film-based approaches), or microfluidic devices. In the second part, the LPME techniques based on porous supports for the extraction solvent such as membranes and porous media are overviewed. An outlook on future demands and perspectives in this promising area of analytical chemistry is finally given. PMID:26772123

  1. Comprehensive Review of the Literature on Existing Punctal Plugs for the Management of Dry Eye Disease

    PubMed Central

    Jehangir, Naz; Bever, Greg; Mahmood, S. M. Jafar; Moshirfar, Majid

    2016-01-01

    Numerous designs of punctal and canalicular plugs are available on the market. This variety presents challenges to ophthalmologists when choosing punctal plugs for the management of various ocular conditions. The aim of this literature review is to provide a classification system for lacrimal occlusive devices based on their location and duration of action as well as to identify different characteristics of each one of them. We want to give a comprehensive overview on punctal and canalicular plugs including their manufacturing companies, indications, and complications that have been reported in various articles. PubMed and Google Scholar were used to identify articles written in English as well as few articles written in Japanese, Chinese, Slovak, and Spanish that had abstracts in English. Nine different companies that manufacture punctal and canalicular plugs were identified and their plugs were included in this review. Punctal and canalicular plugs are used in the management of various ocular conditions including dry eye disease and punctal stenosis as well as in ocular drug delivery. Although they are a relatively safe option, associated complications have been reported in the literature such as infection, allergic reaction, extrusion, and migration. PMID:27088009

  2. Quasi-Porous Plug With Vortex Chamber

    NASA Technical Reports Server (NTRS)

    Walsh, J. V.

    1985-01-01

    Pressure-letdown valve combines quasi-porous-plug and vortex-chamber in one controllable unit. Valve useful in fossil-energy plants for reducing pressures in such erosive two-phase process streams as steam/water, coal slurries, or combustion gases with entrained particles. Quasi-Porous Plug consists of plenums separated by perforated plates. Number or size of perforations increases with each succeeding stage to compensate for expansion. In Vortex Chamber, control flow varies to control swirl and therefore difference between inlet and outlet pressures.

  3. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    PubMed Central

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles A.

    2009-01-01

    The coupling of dosimetry measurements and modeling represents a promising strategy for deciphering the relationship between chemical exposure and disease outcome. To support the development and implementation of biological monitoring programs, quantitative technologies for measuring xenobiotic exposure are needed. The development of portable nanotechnology-based electrochemical sensors has the potential to meet the needs for low cost, rapid, high-throughput and ultrasensitive detectors for biomonitoring an array of chemical markers. Highly selective electrochemical (EC) sensors capable of pM sensitivity, high-throughput and low sample requirements (<50uL) are discussed. These portable analytical systems have many advantages over currently available technologies, thus potentially representing the next-generation of biomonitoring analyzers. This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are presented. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are discussed. PMID:19018275

  4. Nanotechnology-based electrochemical sensors for biomonitoring chemical exposures.

    PubMed

    Barry, Richard C; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles A

    2009-01-01

    The coupling of dosimetry measurements and modeling represents a promising strategy for deciphering the relationship between chemical exposure and disease outcome. To support the development and implementation of biological monitoring programs, quantitative technologies for measuring xenobiotic exposure are needed. The development of portable nanotechnology-based electrochemical (EC) sensors has the potential to meet the needs for low cost, rapid, high-throughput, and ultrasensitive detectors for biomonitoring an array of chemical markers. Highly selective EC sensors capable of pM sensitivity, high-throughput and low sample requirements (<50 microl) are discussed. These portable analytical systems have many advantages over currently available technologies, thus potentially representing the next generation of biomonitoring analyzers. This paper highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are presented. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are discussed.

  5. Tissue-based standoff biosensors for detecting chemical warfare agents

    DOEpatents

    Greenbaum, Elias; Sanders, Charlene A.

    2003-11-18

    A tissue-based, deployable, standoff air quality sensor for detecting the presence of at least one chemical or biological warfare agent, includes: a cell containing entrapped photosynthetic tissue, the cell adapted for analyzing photosynthetic activity of the entrapped photosynthetic tissue; means for introducing an air sample into the cell and contacting the air sample with the entrapped photosynthetic tissue; a fluorometer in operable relationship with the cell for measuring photosynthetic activity of the entrapped photosynthetic tissue; and transmitting means for transmitting analytical data generated by the fluorometer relating to the presence of at least one chemical or biological warfare agent in the air sample, the sensor adapted for deployment into a selected area.

  6. Plug-in hybrid electric vehicle R&D plan

    SciTech Connect

    None, None

    2007-06-01

    FCVT, in consultation with industry and other appropriate DOE offices, developed the Draft Plug-In Hybrid Electric Vehicle R&D Plan to accelerate the development and deployment of technologies critical for plug-in hybrid vehicles.

  7. Polarizing keys prevent mismatch of connector plugs and receptacles

    NASA Technical Reports Server (NTRS)

    Chiapuzio, A.

    1966-01-01

    Keying prevents mismatching of plugs and receptacles in connector patching of instrumentation involving several thousand leads. Each receptacle and plug contains three polarizing keys that must mate in a complementary mode before the connector pins and sockets will engage.

  8. Exploration of chemical space based on 4-anilinoquinazoline.

    PubMed

    Li, D-D; Hou, Y-P; Wang, W; Zhu, H-L

    2012-01-01

    Chemical space is defined as all possible small organic molecules, including those present in biological systems, which is so vast that so far only a tiny fraction of it has been explored. Indeed, a thorough examination of all "chemical space" is practically impossible. The success of three EGFR inhibitors (Gefitnib, Erlotinib, Lapatinib) suggests that 4-anilinoquinazoline scaffold is still worth developing in the future. To date hundreds of this sort of derivatives have been synthesized and show potent anticancer activities. Most of the compounds have been proved to be EGFR/HER2 kinase inhibitors, binding at the hinge region of the ATP site and some lead compounds have been optimized against a number of different kinases, including VEGFR-2, Src, Aurora A/B, Tpl, Clk and PDE10A. Now there is now a rich pipeline of novel anticancer agents based on 4-anilinoquinazoline in early phase clinical trials. This review will highlight the exploration of chemical space of 4-anilinoquinazoline in the past ten years and we hope that increasing knowledge of the SAR and cellular processes underlying the antitumor-activity of anilinoquinazoline derivatives will be beneficial to the rational design of new generation of small molecule anticancer drugs.

  9. [Rationality of commercial specification of rhubarb based on chemical analysis].

    PubMed

    Wang, Jiabo; Zhang, Xueru; Xiao, Xiaohe; Chu, Xiaohui; Zhou, Canping; Jin, Cheng; Yan, Dan

    2010-02-01

    The differences of 34 rhubarb samples collected on the market and at producing area were investigated by chemical analysis on the contents of anthraquinones and chromatographic fingerprints, in order to assess the rationality of the commercial specification of rhubarb. The results indicated that the commercial specification of rhubarb was not correlated to the contents of anthraquinones as well as the price. The chromatographic fingerprints of rhubarb samples from different producing area were dissimilar, while the commercial specifications were difficult to be separated. Generally, the rhubarb samples produced in famous-region contained more anthraquinones. This demonstrated rationality on the traditional records of the famous-region of rhubarb from a chemical view. In this study, it was firstly reported that rhubarb could be categorized into two types, chrysophanol-type and rhein-type, based on the proportion of the two constituents in the total anthraquinones after acid hydrohysis. It was found that the rhubarb samples of rhein-type were mostly produced in famous-regions, such as Qinghai, Xizang, West Sichuan and Gansu. The literatures reported that rhein was superior to chrysophanol at many pharmacological effects and pharmacokinetic properties. Hence, we primarily considered that rhein-type rhubarb might be high-quality. These results were helpful to improve the commercial specification of rhubarb from a view of chemical information.

  10. SpaceWire Plug and Play Updates

    NASA Technical Reports Server (NTRS)

    Rakow, Glenn

    2007-01-01

    This viewgraph presentation reviews the work of the SpaceWire Plug N Play Workgroup. (SpW PnP WG). The chief product of SpW PnP WG will be to develop specification of necessary hardware features required in support upper layer (software) PnP implementations.

  11. 49 CFR 230.58 - Flue plugs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Flue plugs. 230.58 Section 230.58 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

  12. 49 CFR 230.58 - Flue plugs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Flue plugs. 230.58 Section 230.58 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

  13. 49 CFR 230.58 - Flue plugs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Flue plugs. 230.58 Section 230.58 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

  14. 49 CFR 230.58 - Flue plugs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Flue plugs. 230.58 Section 230.58 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

  15. 49 CFR 230.58 - Flue plugs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Flue plugs. 230.58 Section 230.58 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances...

  16. Jet noise suppression by porous plug nozzles

    NASA Technical Reports Server (NTRS)

    Bauer, A. B.; Kibens, V.; Wlezien, R. W.

    1982-01-01

    Jet noise suppression data presented earlier by Maestrello for porous plug nozzles were supplemented by the testing of a family of nozzles having an equivalent throat diameter of 11.77 cm. Two circular reference nozzles and eight plug nozzles having radius ratios of either 0.53 or 0.80 were tested at total pressure ratios of 1.60 to 4.00. Data were taken both with and without a forward motion or coannular flow jet, and some tests were made with a heated jet. Jet thrust was measured. The data were analyzed to show the effects of suppressor geometry on nozzle propulsive efficiency and jet noise. Aerodynamic testing of the nozzles was carried out in order to study the physical features that lead to the noise suppression. The aerodynamic flow phenomena were examined by the use of high speed shadowgraph cinematography, still shadowgraphs, extensive static pressure probe measurements, and two component laser Doppler velocimeter studies. The different measurement techniques correlated well with each other and demonstrated that the porous plug changes the shock cell structure of a standard nozzle into a series of smaller, periodic cell structures without strong shock waves. These structures become smaller in dimension and have reduced pressure variations as either the plug diameter or the porosity is increased, changes that also reduce the jet noise and decrease thrust efficiency.

  17. QCL-based standoff and proximal chemical detectors

    NASA Astrophysics Data System (ADS)

    Dupuis, Julia R.; Hensley, Joel; Cosofret, Bogdan R.; Konno, Daisei; Mulhall, Phillip; Schmit, Thomas; Chang, Shing; Allen, Mark; Marinelli, William J.

    2016-05-01

    The development of two longwave infrared quantum cascade laser (QCL) based surface contaminant detection platforms supporting government programs will be discussed. The detection platforms utilize reflectance spectroscopy with application to optically thick and thin materials including solid and liquid phase chemical warfare agents, toxic industrial chemicals and materials, and explosives. Operation at standoff (10s of m) and proximal (1 m) ranges will be reviewed with consideration given to the spectral signatures contained in the specular and diffusely reflected components of the signal. The platforms comprise two variants: Variant 1 employs a spectrally tunable QCL source with a broadband imaging detector, and Variant 2 employs an ensemble of broadband QCLs with a spectrally selective detector. Each variant employs a version of the Adaptive Cosine Estimator for detection and discrimination in high clutter environments. Detection limits of 5 μg/cm2 have been achieved through speckle reduction methods enabling detector noise limited performance. Design considerations for QCL-based standoff and proximal surface contaminant detectors are discussed with specific emphasis on speckle-mitigated and detector noise limited performance sufficient for accurate detection and discrimination regardless of the surface coverage morphology or underlying surface reflectivity. Prototype sensors and developmental test results will be reviewed for a range of application scenarios. Future development and transition plans for the QCL-based surface detector platforms are discussed.

  18. Bond strength of cementitious borehole plugs in welded tuff

    SciTech Connect

    Akgun, H.; Daemen, J.J.K.

    1991-02-01

    Axial loads on plugs or seals in an underground repository due to gas, water pressures and temperature changes induced subsequent to waste and plug emplacement lead to shear stresses at the plug/rock contact. Therefore, the bond between the plug and rock is a critical element for the design and effectiveness of plugs in boreholes, shafts or tunnels. This study includes a systematic investigation of the bond strength of cementitious borehole plugs in welded tuff. Analytical and numerical analysis of borehole plug-rock stress transfer mechanics is performed. The interface strength and deformation are studied as a function of Young`s modulus ratio of plug and rock, plug length and rock cylinder outside-to-inside radius ratio. The tensile stresses in and near an axially loaded plug are analyzed. The frictional interface strength of an axially loaded borehole plug, the effect of axial stress and lateral external stress, and thermal effects are also analyzed. Implications for plug design are discussed. The main conclusion is a strong recommendation to design friction plugs in shafts, drifts, tunnels or boreholes with a minimum length to diameter ratio of four. Such a geometrical design will reduce tensile stresses in the plug and in the host rock to a level which should minimize the risk of long-term deterioration caused by excessive tensile stresses. Push-out tests have been used to determine the bond strength by applying an axial load to cement plugs emplaced in boreholes in welded tuff cylinders. A total of 130 push-out tests have been performed as a function of borehole size, plug length, temperature, and degree of saturation of the host tuff. The use of four different borehole radii enables evaluation of size effects. 119 refs., 42 figs., 20 tabs.

  19. Aeroacoustics of a porous plug supersonic jet noise suppressor

    NASA Technical Reports Server (NTRS)

    Dosanjh, D. S.; Matambo, T. J.; Das, I. S.

    1983-01-01

    The aeroacoustics of a porous plug supersonic jet noise suppressor was investigated. The needed modifications of the existing multistream coaxial jet rig; the compressed air facility and pressure controls; the design, the fabrication, and the installation of the plenum chamber for the plug nozzle, and the design and the machining of the first contoured plug nozzle were completed. The optical and the aeroacoustic data of the contoured plug nozzles and of the conical convergent nozzle alone were discussed.

  20. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    SciTech Connect

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles

    2009-01-01

    This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are discussed. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are covered.

  1. Toxic neuropathies: Mechanistic insights based on a chemical perspective.

    PubMed

    LoPachin, Richard M; Gavin, Terrence

    2015-06-01

    2,5-Hexanedione (HD) and acrylamide (ACR) are considered to be prototypical among chemical toxicants that cause central-peripheral axonopathies characterized by distal axon swelling and degeneration. Because the demise of distal regions was assumed to be causally related to the onset of neurotoxicity, substantial effort was devoted to deciphering the respective mechanisms. Continued research, however, revealed that expression of the presumed hallmark morphological features was dependent upon the daily rate of toxicant exposure. Indeed, many studies reported that the corresponding axonopathic changes were late developing effects that occurred independent of behavioral and/or functional neurotoxicity. This suggested that the toxic axonopathy classification might be based on epiphenomena related to dose-rate. Therefore, the goal of this mini-review is to discuss how quantitative morphometric analyses and the establishment of dose-dependent relationships helped distinguish primary, mechanistically relevant toxicant effects from non-specific consequences. Perhaps more importantly, we will discuss how knowledge of neurotoxicant chemical nature can guide molecular-level research toward a better, more rational understanding of mechanism. Our discussion will focus on HD, the neurotoxic γ-diketone metabolite of the industrial solvents n-hexane and methyl-n-butyl ketone. Early investigations suggested that HD caused giant neurofilamentous axonal swellings and eventual degeneration in CNS and PNS. However, as our review will point out, this interpretation underwent several iterations as the understanding of γ-diketone chemistry improved and more quantitative experimental approaches were implemented. The chemical concepts and design strategies discussed in this mini-review are broadly applicable to the mechanistic studies of other chemicals (e.g., n-propyl bromine, methyl methacrylate) that cause toxic neuropathies.

  2. 40 CFR 147.3102 - Plugging and abandonment plans.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Plugging and abandonment plans. 147... Certain Oklahoma Indian Tribes § 147.3102 Plugging and abandonment plans. In lieu of the requirements of... with the plugging and abandonment provisions of § 147.3108 of this subpart....

  3. 40 CFR 147.3102 - Plugging and abandonment plans.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Plugging and abandonment plans. 147... Certain Oklahoma Indian Tribes § 147.3102 Plugging and abandonment plans. In lieu of the requirements of... with the plugging and abandonment provisions of § 147.3108 of this subpart....

  4. 40 CFR 147.3102 - Plugging and abandonment plans.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Plugging and abandonment plans. 147... Certain Oklahoma Indian Tribes § 147.3102 Plugging and abandonment plans. In lieu of the requirements of... with the plugging and abandonment provisions of § 147.3108 of this subpart....

  5. 40 CFR 147.3102 - Plugging and abandonment plans.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Plugging and abandonment plans. 147... Certain Oklahoma Indian Tribes § 147.3102 Plugging and abandonment plans. In lieu of the requirements of... with the plugging and abandonment provisions of § 147.3108 of this subpart....

  6. 40 CFR 147.3102 - Plugging and abandonment plans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Plugging and abandonment plans. 147... Certain Oklahoma Indian Tribes § 147.3102 Plugging and abandonment plans. In lieu of the requirements of... with the plugging and abandonment provisions of § 147.3108 of this subpart....

  7. 21 CFR 878.4755 - Absorbable lung biopsy plug.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Absorbable lung biopsy plug. 878.4755 Section 878...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4755 Absorbable lung biopsy plug. (a) Identification. A preformed (polymerized) absorbable lung biopsy plug is intended to...

  8. Compact Fluorescent Plug-In Ballast-in-a-Socket

    SciTech Connect

    Rebecca Voelker

    2001-12-21

    The primary goal of this program was to develop a ballast system for plug-in CFLs (compact fluorescent lamps) that will directly replace standard metal shell, medium base incandescent lampholders (such as Levition No. 6098) for use with portable lamp fixtures, such as floor, table and desk lamps. A secondary goal was to identify a plug-in CFL that is optimized for use with this ballast. This Plug-in CFL Ballastin-a-Socket system will allow fixture manufacturers to easily manufacture CFL-based high-efficacy portable fixtures that provide residential and commercial consumers with attractive, cost-effective, and energy-efficient fixtures for use wherever portable incandescent fixtures are used today. The advantages of this proposed system over existing CFL solutions are that the fixtures can only be used with high-efficacy CFLs, and they will be more attractive and will have lower life-cycle costs than screw-in or adapter-based CFL retrofit solutions. These features should greatly increase the penetration of CFL's into the North American market. Our work has shown that using integrated circuits it is quite feasible to produce a lamp-fixture ballast of a size comparable to the current Edison-screw 3-way incandescent fixtures. As for price points for BIAS-based fixtures, end-users polled by the Lighting Research Institute at RPI indicated that they would pay as much as an additional $10 for a lamp containing such a ballast. The ballast has been optimized to run with a 26 W amalgam triple biax lamp in the base-down position, yet can accept non-amalgam versions of the lamp. With a few part alterations, the ballast can be produced to support 32 W lamps as well. The ballast uses GE's existing L-Comp[1] power topology in the circuit so that the integrated circuit design would be a design that could possibly be used by other CFL and EFL products with minor modifications. This gives added value by reducing cost and size of not only the BIAS, but also possibly other integral

  9. Safety upgrades plug car leaks

    SciTech Connect

    Not Available

    1993-08-01

    To lessen the chance of a chemical leak occurring during rail transport, some companies are improving tank car sturdiness and safety by adding such features as top-loading valves, on-board monitoring devices, and thicker, more impact-resistant hulls. Results include a dramatic drop in the number of rail incidents and leak tank cars. Chemicals Division of Olin Corporation (Stamford, Connecticut) has assigned its name to a new fleet of chlorine, caustic soda and toluene diisocyanate (TDI) tank cars. Each car carries the company's Care[trademark]Car registered trademark. The upgrade is part of a company-wide quality improvement process started in 1986. The company requires acoustic emissions (AE) testing on all hazardous materials tank cars. If an area has a defect, it expands and makes a slight sound when subjected to stress. In an AE test, cars are subject to simulated bumps and jolts as in rail shipment. Electronic sensors transfer any stress noises onto a computer screen, where an operator can pinpoint the trouble source.

  10. Carbon Nanotube Based Chemical Sensors for Space and Terrestrial Applications

    NASA Technical Reports Server (NTRS)

    Li, Jing; Lu, Yijiang

    2009-01-01

    A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs), on a pair of interdigitated electrodes (IDE) processed with a silicon-based microfabrication and micromachining technique. The IDE fingers were fabricated using photolithography and thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to nitrogen dioxide, acetone, benzene, nitrotoluene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing of carbon nanotubes in our sensor platform can be understood by intra- and inter-tube electron modulation in terms of charge transfer mechanisms. As a result of the charge transfer, the conductance of p-type or hole-richer SWNTs in air will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost. Additionally, a wireless capability of such a sensor chip can be used for networked mobile and fixed-site detection and warning systems for military bases, facilities and battlefield areas.

  11. Photonic crystal fiber based chloride chemical sensors for corrosion monitoring

    NASA Astrophysics Data System (ADS)

    Wei, Heming; Tao, Chuanyi; Krishnaswamy, Sridhar

    2016-04-01

    Corrosion of steel is one of the most important durability issues in reinforced concrete (RC) structures because aggressive ions such as chloride ions permeate concrete and corrode steel, consequently accelerating the destruction of structures, especially in marine environments. There are many practical methods for corrosion monitoring in RC structures, mostly focusing on electrochemical-based sensors for monitoring the chloride ion which is thought as one of the most important factors resulting in steel corrosion. In this work, we report a fiber-optic chloride chemical sensor based on long period gratings inscribed in a photonic crystal fiber (PCF) with a chloride sensitive thin film. Numerical simulation is performed to determine the characteristics and resonance spectral response versus the refractive indices of the analyte solution flowing through into the holes in the PCF. The effective refractive index of the cladding mode of the LPGs changes with variations of the analyte solution concentration, resulting in a shift of the resonance wavelength, hence providing the sensor signal. This fiber-optic chemical sensor has a fast response, is easy to prepare and is not susceptible to electromagnetic environment, and can therefore be of use for structural health monitoring of RC structures subjected to such aggressive environments.

  12. Chemical switch based reusable dual optoelectronic sensor for nitrite.

    PubMed

    Vishnuvardhan, V; Kala, R; Prasada Rao, T

    2008-08-01

    An optical sensor was developed for sensing of nitrite based on the monotonous decrease in absorbance of Rhodamine 6G at 525 nm (the absorbance maximum of dye) with increasing concentration of nitrite. This sensor also permits naked eye detection. Various parameters like concentrations of sulphuric acid and Rhodamine 6G, response time and stability were varied and optimal conditions are reported. Under these conditions, the developed sensor enables the determination of nitrite in the concentration range 0-12.18 micromol L(-1). The nitrite response is selective as 60-2.5x10(5) fold amounts of several anions and cations have no deleterious effect. The addition of nitrite to Rhodamine 6G dye causes hypsochromic shift from 525 to 385 nm while several other anions like I(-), SCN(-), ClO(4)(-), [HgI(4)](2-) and [Zn (SCN)(4)](2-) showed a bathochromatic shift from 525 to 575 nm. The sequential addition of nitrite and sulphamic to Rhodamine 6G in 0.75 mol L(-1) sulphuric acid solution results in switching of "ON" and "OFF" absorbance. The time elapse and concentration of sulphamic acid required for chemical switching was also established. Similar "ON" and "OFF" switching behaviour was observed in fluorescence studies also. This enabled the design and development of reusable chemical switch based dual optoelectronic sensor, for monitoring of traces of nitrite in environmental and food samples. The plausible mechanism for above switching behaviour is also proposed.

  13. Physics-based model for electro-chemical process

    SciTech Connect

    Zhang, Jinsuo

    2013-07-01

    Considering the kinetics of electrochemical reactions and mass transfer at the surface and near-surface of the electrode, a physics-based separation model for separating actinides from fission products in an electro-refiner is developed. The model, taking into account the physical, chemical and electrochemical processes at the electrode surface, can be applied to study electrorefining kinetics. One of the methods used for validation has been to apply the developed model to the computation of the cyclic voltammetry process of PuCl{sub 3} and UCl{sub 3} at a solid electrode in molten KCl-LiCl. The computed results appear to be similar to experimental measures. The separation model can be applied to predict materials flows under normal and abnormal operation conditions. Parametric studies can be conducted based on the model to identify the most important factors that affect the electrorefining processes.

  14. Plug-In Hybrid Electric Vehicle Penetration Scenarios

    SciTech Connect

    Balducci, Patrick J.

    2008-04-03

    This report examines the economic drivers, technology constraints, and market potential for plug-in hybrid electric vehicles (PHEVs) in the U.S. A PHEV is a hybrid vehicle with batteries that can be recharged by connecting to the grid and an internal combustion engine that can be activated when batteries need recharging. The report presents and examines a series of PHEV market penetration scenarios. Based on input received from technical experts and industry representative contacted for this report and data obtained through a literature review, annual market penetration rates for PHEVs are presented from 2013 through 2045 for three scenarios. Each scenario is examined and implications for PHEV development are explored.

  15. Design and characterization of integrated-optic-based chemical sensors

    NASA Astrophysics Data System (ADS)

    Beregovskii, Iouri

    A novel line of integrated-optic-based chemical sensors was developed. The sensors are based on modification of the optical cavity of a single-mode semiconductor distributed Bragg reflector (DBR) laser. A sensitive layer changes its refractive index in presence of a specific chemical, thus changing the effective refractive index of the section and the optical length of the cavity. This results in laser frequency shift measured either directly or by heterodyne detection using a reference laser as the second source. It is shown that DBR-laser-based sensors can achieve in principle a much higher sensitivity than passive sensors, such as Mach- Zehnder interferometers, due to the narrow linewidth of DBR lasers. The theory of DBR-laser-based sensors is described. It allows optimizing the sensitive section length and field confinement in the sensitive layer for the lowest detection limit. The optimum parameters depend on cavity losses and absorption of the sensitive material. Numerical modeling shows a wide acceptable range of sensitive section parameters for low-loss materials, while for higher-loss materials this range becomes much narrower. Narrow-linewidth DBR lasers are required for high sensitivity. In this respect, sol-gel waveguides with and without Bragg grating were incorporated in the DBR laser scheme. Single-mode operation of DBR lasers with sol-gel waveguide gratings was demonstrated for the first time, with 34-dB side mode suppression and a short-term linewidth of 150 to 500 kHz. A 3-section configuration with sol-gel waveguides and fiber grating showed 28-dB side mode suppression and a short-term linewidth of 600 kHz. Chemical sensing was performed with fiber grating, sol- gel waveguide grating, and 3-section DBR lasers. The first two types showed frequency shift of over 130 MHz in the presence of acetone vapors, and reversibility within experimental errors. The 3-section scheme showed significant dispersion of response and lack of reversibility due to

  16. Graphene-Based Chemical Vapor Sensors for Electronic Nose Applications

    NASA Astrophysics Data System (ADS)

    Nallon, Eric C.

    chemiresistor device and used as a chemical sensor, where its resistance is temporarily modified while exposed to chemical compounds. The inherent, broad selective nature of graphene is demonstrated by testing a sensor against a diverse set of volatile organic compounds and also against a set of chemically similar compounds. The sensor exhibits excellent selectivity and is capable of achieving high classification accuracies. The kinetics of the sensor's response are further investigated revealing a relationship between the transient behavior of the response curve and physiochemical properties of the compounds, such as the molar mass and vapor pressure. This kinetic information is also shown to provide important information for further pattern recognition and classification, which is demonstrated by increased classification accuracy of very similar compounds. Covalent modification of the graphene surface is demonstrated by means of plasma treatment and free radical exchange, and sensing performance compared to an unmodified graphene sensor. Finally, the first example of a graphene-based, cross-reactive chemical sensor array is demonstrated by applying various polymers as coatings over an array of graphene sensors. The sensor array is tested against a variety of compounds, including the complex odor of Scotch whiskies, where it is capable of perfect classification of 10 Scotch whiskey variations.

  17. Damage Tolerance Assessment of Friction Pull Plug Welds in an Aluminum Alloy

    NASA Technical Reports Server (NTRS)

    McGill, Preston; Burkholder, Jonathan

    2012-01-01

    Friction stir welding is a solid state welding process used in the fabrication of cryogenic propellant tanks. Self-reacting friction stir welding is one variation of the friction stir weld process being developed for manufacturing tanks. Friction pull plug welding is used to seal the exit hole that remains in a circumferential self-reacting friction stir weld. A friction plug weld placed in a self-reacting friction stir weld results in a non-homogenous weld joint where the initial weld, plug weld, their respective heat affected zones and the base metal all interact. The welded joint is a composite plastically deformed material system with a complex residual stress field. In order to address damage tolerance concerns associated with friction plug welds in safety critical structures, such as propellant tanks, nondestructive inspection and proof testing may be required to screen hardware for mission critical defects. The efficacy of the nondestructive evaluation or the proof test is based on an assessment of the critical flaw size. Test data relating residual strength capability to flaw size in an aluminum alloy friction plug weld will be presented.

  18. Mechanism-based bioanalysis and biomarkers for hepatic chemical stress.

    PubMed

    Antoine, D J; Mercer, A E; Williams, D P; Park, B K

    2009-08-01

    Adverse drug reactions, in particular drug-induced hepatotoxicity, represent a major challenge for clinicians and an impediment to safe drug development. Novel blood or urinary biomarkers of chemically-induced hepatic stress also hold great potential to provide information about pathways leading to cell death within tissues. The earlier pre-clinical identification of potential hepatotoxins and non-invasive diagnosis of susceptible patients, prior to overt liver disease is an important goal. Moreover, the identification, validation and qualification of biomarkers that have in vitro, in vivo and clinical transferability can assist bridging studies and accelerate the pace of drug development. Drug-induced chemical stress is a multi-factorial process, the kinetics of the interaction between the hepatotoxin and the cellular macromolecules are crucially important as different biomarkers will appear over time. The sensitivity of the bioanalytical techniques used to detect biological and chemical biomarkers underpins the usefulness of the marker in question. An integrated analysis of the biochemical, molecular and cellular events provides an understanding of biological (host) factors which ultimately determine the balance between xenobiotic detoxification, adaptation and liver injury. The aim of this review is to summarise the potential of novel mechanism-based biomarkers of hepatic stress which provide information to connect the intracellular events (drug metabolism, organelle, cell and whole organ) ultimately leading to tissue damage (apoptosis, necrosis and inflammation). These biomarkers can provide both the means to inform the pharmacologist and chemist with respect to safe drug design, and provide clinicians with valuable tools for patient monitoring. PMID:19621999

  19. Non-rotating cementing plug with molded inserts

    SciTech Connect

    Watson, B.W.

    1992-03-17

    This patent describes an anti-rotation plug set for use with cementing equipment having an insert seat therein, the anti-rotation plug set and the cementing equipment for use in cementing a string of casing into a well bore. It comprises an upper plug including: a non-metallic body member having a plurality of teeth integrally formed on the lower end thereof and an elastomeric covering thereon having, in turn, wipers which engage the interior of the string of casing; and a lower plug including: a non-metallic body member having a bore therethrough, having teeth integrally formed on the upper end thereof which mate with the teeth integrally formed on the lower end of the nonmetallic body member of the upper plug when the upper plug engages the lower plugs, having teeth integrally formed on the lower end thereof, having an insert member in a portion of the bore through the non-metallic body member, and the cementing equipment comprising: an insert seat having teeth thereon which mate with the integrally formed teeth on the lower end of the non-metallic body member of the lower plug of the anti-rotation plug set when the lower plug of the anti-rotation plug set engages the cementing equipment during the cementing of the string of casing into a well bore.

  20. Application of physiologically based pharmacokinetic models in chemical risk assessment.

    PubMed

    Mumtaz, Moiz; Fisher, Jeffrey; Blount, Benjamin; Ruiz, Patricia

    2012-01-01

    Post-exposure risk assessment of chemical and environmental stressors is a public health challenge. Linking exposure to health outcomes is a 4-step process: exposure assessment, hazard identification, dose response assessment, and risk characterization. This process is increasingly adopting "in silico" tools such as physiologically based pharmacokinetic (PBPK) models to fine-tune exposure assessments and determine internal doses in target organs/tissues. Many excellent PBPK models have been developed. But most, because of their scientific sophistication, have found limited field application-health assessors rarely use them. Over the years, government agencies, stakeholders/partners, and the scientific community have attempted to use these models or their underlying principles in combination with other practical procedures. During the past two decades, through cooperative agreements and contracts at several research and higher education institutions, ATSDR funded translational research has encouraged the use of various types of models. Such collaborative efforts have led to the development and use of transparent and user-friendly models. The "human PBPK model toolkit" is one such project. While not necessarily state of the art, this toolkit is sufficiently accurate for screening purposes. Highlighted in this paper are some selected examples of environmental and occupational exposure assessments of chemicals and their mixtures. PMID:22523493

  1. Chemical Signaling and Functional Activation in Colloidosome-Based Protocells.

    PubMed

    Sun, Shiyong; Li, Mei; Dong, Faqin; Wang, Shengjie; Tian, Liangfei; Mann, Stephen

    2016-04-13

    An aqueous-based microcompartmentalized model involving the integration of partially hydrophobic Fe(III)-rich montmorillonite (FeM) clay particles as structural and catalytic building blocks for colloidosome membrane assembly, self-directed membrane remodeling, and signal-induced protocell communication is described. The clay colloidosomes exhibit size- and charge-selective permeability, and show dual catalytic functions involving spatially confined enzyme-mediated dephosphorylation and peroxidase-like membrane activity. The latter is used for the colloidosome-mediated synthesis and assembly of a temperature-responsive poly(N-isopropylacrylamide)(PNIPAM)/clay-integrated hybrid membrane. In situ PNIPAM elaboration of the membrane is coupled to a glucose oxidase (GOx)-mediated signaling pathway to establish a primitive model of chemical communication and functional activation within a synthetic "protocell community" comprising a mixed population of GOx-containing silica colloidosomes and alkaline phosphatase (ALP)-containing FeM-clay colloidosomes. Triggering the enzyme reaction in the silica colloidosomes gives a hydrogen peroxide signal that induces polymer wall formation in a coexistent population of the FeM-clay colloidosomes, which in turn generates self-regulated membrane-gated ALP-activity within the clay microcompartments. The emergence of new functionalities in inorganic colloidosomes via chemical communication between different protocell populations provides a first step toward the realization of interacting communities of synthetic functional microcompartments. PMID:26923794

  2. Impedimetric thrombin aptasensor based on chemically modified graphenes

    NASA Astrophysics Data System (ADS)

    Loo, Adeline Huiling; Bonanni, Alessandra; Pumera, Martin

    2011-12-01

    Highly sensitive biosensors are of high importance to the biomedical field. Graphene represents a promising transducing platform for construction of biosensors. Here for the first time we compare the biosensing performance of a wide set of graphenes prepared by different methods. In this work, we present a simple and label-free electrochemical impedimetric aptasensor for thrombin based on chemically modified graphene (CMG) platforms such as graphite oxide (GPO), graphene oxide (GO), thermally reduced graphene oxide (TR-GO) and electrochemically reduced graphene oxide (ER-GO). Disposable screen-printed electrodes were first modified with chemically modified graphene (CMG) materials and used to immobilize a DNA aptamer which is specific to thrombin. The basis of detection relies on the changes in impedance spectra of redox probe after the binding of thrombin to the aptamer. It was discovered that graphene oxide (GO) is the most suitable material to be used as compared to the other three CMG materials. Furthermore, the optimum concentration of aptamer to be immobilized onto the modified electrode surface was determined to be 10 μM and the linear detection range of thrombin was 10-50 nM. Lastly, the aptasensor was found to demonstrate selectivity for thrombin. Such simply fabricated graphene oxide aptasensor shows high promise for clinical diagnosis of biomarkers and point-of-care analysis.

  3. Application of Physiologically Based Pharmacokinetic Models in Chemical Risk Assessment

    PubMed Central

    Mumtaz, Moiz; Fisher, Jeffrey; Blount, Benjamin; Ruiz, Patricia

    2012-01-01

    Post-exposure risk assessment of chemical and environmental stressors is a public health challenge. Linking exposure to health outcomes is a 4-step process: exposure assessment, hazard identification, dose response assessment, and risk characterization. This process is increasingly adopting “in silico” tools such as physiologically based pharmacokinetic (PBPK) models to fine-tune exposure assessments and determine internal doses in target organs/tissues. Many excellent PBPK models have been developed. But most, because of their scientific sophistication, have found limited field application—health assessors rarely use them. Over the years, government agencies, stakeholders/partners, and the scientific community have attempted to use these models or their underlying principles in combination with other practical procedures. During the past two decades, through cooperative agreements and contracts at several research and higher education institutions, ATSDR funded translational research has encouraged the use of various types of models. Such collaborative efforts have led to the development and use of transparent and user-friendly models. The “human PBPK model toolkit” is one such project. While not necessarily state of the art, this toolkit is sufficiently accurate for screening purposes. Highlighted in this paper are some selected examples of environmental and occupational exposure assessments of chemicals and their mixtures. PMID:22523493

  4. Polysaccharides and bacterial plugging. [Leuconostoc bacteria

    SciTech Connect

    Fogler, H.S.

    1992-01-01

    The objectives of this research are to elucidate and model bacterial transport in porous media, to determine the importance of polysaccharides bridging as a retentive mechanism, and to identify key parameters that influence porous media plugging. This project has been subdivided into three tasks: Task 1 is the determination of the growth kinetics of the Leuconostoc bacteria and how they are affected by (1) the nutrient feed, and (2) surface effects; Task 2 will quantify the importance of polysaccharide production as a cell retention mechanism; and Task 3 is the elucidation of the rate of polysaccharide production and the combined effect that polysaccharide production and cell growth has upon plugging. Batch growth experiments have been conducted to determine the rate of cell growth, polymer production and nutrient consumption. The data from these experiments are currently being reduced to aid the development of an overall growth model.

  5. Instantaneous physico-chemical analysis of suspension-based nanomaterials

    PubMed Central

    Meng, Fanxu; Ugaz, Victor M.

    2015-01-01

    High-throughput manufacturing of nanomaterial-based products demands robust online characterization and quality control tools capable of continuously probing the in-suspension state. But existing analytical techniques are challenging to deploy in production settings because they are primarily geared toward small-batch ex-situ operation in research laboratory environments. Here we introduce an approach that overcomes these limitations by exploiting surface complexation interactions that emerge when a micron-scale chemical discontinuity is established between suspended nanoparticles and a molecular tracer. The resulting fluorescence signature is easily detectable and embeds surprisingly rich information about composition, quantity, size, and morphology of nanoparticles in suspension independent of their agglomeration state. We show how this method can be straightforwardly applied to enable continuous sizing of commercial ZnO nanoparticles, and to instantaneously quantify the anatase and rutile composition of multicomponent TiO2 nanoparticle mixtures pertinent to photocatalysis and solar energy conversion. PMID:25923196

  6. Chemical sensors based on surface-confined dendrimers

    SciTech Connect

    Tokuhisa, Hideo; Crooks, R.M.; Ricco, A.J.; Osbourn, G.C.

    1997-10-01

    The use of dendrimers for preparing chemically sensitive interfaces for detecting volatile organic compounds (VOCs) using surface acoustic wave (SAW) device transducers is described. Specifically, the synthesis of the dendrimers and the means by which they are affixed to SAW devices is discussed, followed by a detailed spectroscopic analysis of the surface-confined dendrimers and a discussion of their interaction with different VOCs. Most of these preliminary experiments focus on dendrimer surface modification using benzoylchloride, which leads to phenyl terminal groups linked to the dendrimer via amide groups. The results of this study lead us to conclude that dendrimers: (1) provide general specificity towards classes of functional groups and are therefore suitable for array-based sensing schemes; (2) are intermediate in structure between monolayers and polymers and exhibit the desirable properties of both; (3) can be straightforwardly attached to the surfaces of acoustic wave devices.

  7. Limiting factors for carbon based chemical double layer capacitors

    NASA Technical Reports Server (NTRS)

    Rose, M. Frank; Johnson, C.; Owens, T.; Stevens, B.

    1993-01-01

    The Chemical Double Layer (CDL) capacitor improves energy storage density dramatically when compared with conventional electrolytic capacitors. When compared to batteries, the CDL Capacitor is much less energy dense; however, the power density is orders of magnitude better. As a result, CDL-battery combinations present an interesting pulse power system with many potential applications. Due to the nature of the CDL it is inherently a low voltage device. The applications of the CDL can be tailored to auxiliary energy and burst mode storages which require fast charge/discharge cycles. Typical of the applications envisioned are power system backup, directed energy weapons concepts, electric automobiles, and electric actuators. In this paper, we will discuss some of the general characteristics of carbon-based CDL technology describing the structure, performance parameters, and methods of construction. Further, analytical and experimental results which define the state of the art are presented and described in terms of impact on applications.

  8. Plug into a Great Outlet for Creativity

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2009-01-01

    Is there beauty in the wall socket that people plug their appliances into daily? Can one find beauty in the grate covering the heat vent in his classroom? The author posed these very questions to her third-grade students. She had the students take a good look at the outlet cover (or plate) on the wall. After thinking and discussing the outlets,…

  9. Trends in information theory-based chemical structure codification.

    PubMed

    Barigye, Stephen J; Marrero-Ponce, Yovani; Pérez-Giménez, Facundo; Bonchev, Danail

    2014-08-01

    This report offers a chronological review of the most relevant applications of information theory in the codification of chemical structure information, through the so-called information indices. Basically, these are derived from the analysis of the statistical patterns of molecular structure representations, which include primitive global chemical formulae, chemical graphs, or matrix representations. Finally, new approaches that attempt to go "back to the roots" of information theory, in order to integrate other information-theoretic measures in chemical structure coding are discussed.

  10. Chemical fingerprinting of silicone-based breast implants.

    PubMed

    Keizers, Peter H J; Vredenbregt, Marjo J; Bakker, Frank; de Kaste, Dries; Venhuis, Bastiaan J

    2015-01-01

    With millions of women worldwide carrying them, silicone-based breast implants represent a large market. Even though silicone breast implants already have a history of use of more than 50 years, the discussion on their safety has not yet come to an end. To improve safety assessment, regulatory authorities should have the availability of a set of tests to be able to determine parameters of implant identity and quality. Therefore, the gels and envelopes of various brands and types of silicone-based breast implants have been subjected to infrared, Raman and NMR spectroscopy. We show that by using a combination of complementary spectroscopic techniques breast implants of various origins can be distinguished on typical chemical hallmarks. It was found that typical silicone-based implants display a surplus of vinyl signals in the gel, cyclosiloxane impurities are tolerable at low levels only and a barrier layer is present in the implant envelope. The techniques presented here and the results obtained offer a good starting point for market surveillance studies. PMID:25459933

  11. Chemically engineered graphene-based 2D organic molecular magnet.

    PubMed

    Hong, Jeongmin; Bekyarova, Elena; de Heer, Walt A; Haddon, Robert C; Khizroev, Sakhrat

    2013-11-26

    Carbon-based magnetic materials and structures of mesoscopic dimensions may offer unique opportunities for future nanomagnetoelectronic/spintronic devices. To achieve their potential, carbon nanosystems must have controllable magnetic properties. We demonstrate that nitrophenyl functionalized graphene can act as a room-temperature 2D magnet. We report a comprehensive study of low-temperature magnetotransport, vibrating sample magnetometry (VSM), and superconducting quantum interference (SQUID) measurements before and after radical functionalization. Following nitrophenyl (NP) functionalization, epitaxially grown graphene systems can become organic molecular magnets with ferromagnetic and antiferromagnetic ordering that persists at temperatures above 400 K. The field-dependent, surface magnetoelectric properties were studied using scanning probe microscopy (SPM) techniques. The results indicate that the NP-functionalization orientation and degree of coverage directly affect the magnetic properties of the graphene surface. In addition, graphene-based organic magnetic nanostructures were found to demonstrate a pronounced magneto-optical Kerr effect (MOKE). The results were consistent across different characterization techniques and indicate room-temperature magnetic ordering along preferred graphene orientations in the NP-functionalized samples. Chemically isolated graphene nanoribbons (CINs) were observed along the preferred functionality directions. These results pave the way for future magnetoelectronic/spintronic applications based on promising concepts such as current-induced magnetization switching, magnetoelectricity, half-metallicity, and quantum tunneling of magnetization.

  12. Evidence-Based Approaches to Improving Chemical Equilibrium Instruction

    ERIC Educational Resources Information Center

    Davenport, Jodi L.; Leinhardt, Gaea; Greeno, James; Koedinger, Kenneth; Klahr, David; Karabinos, Michael; Yaron, David J.

    2014-01-01

    Two suggestions for instruction in chemical equilibrium are presented, along with the evidence that supports these suggestions. The first is to use diagrams to connect chemical reactions to the effects of reactions on concentrations. The second is the use of the majority and minority species (M&M) strategy to analyze chemical equilibrium…

  13. Insertion assembly for a pipe completion plug

    SciTech Connect

    Jiles, S.L.

    1991-08-13

    This patent describes an insertion assembly for installing a completion plug in a branching saddle having an internally-threaded pipe stub and a peripheral beveled seating surface in the pipe stub. It comprises a tube; a shaft extending through the tube; a spring-loaded socket extending partially into one end of the tube, resiliently biased against further movement into the tube and mounted on one end of the shaft so as to turn with it; a completion plug having an elastomeric disk with a beveled peripheral edge and a circular metal plate attached to the disk; a camming groove at the end of the tube and a camming pin extending from the hub to releasably retain the plate at the end of the tube, the groove having a radially-extending portion terminating in a pair of axially-extending recesses for receiving the pin and an axially-extending inlet slot between the recesses, whereby the completion plug may be lowered into place in the branching saddle by means of the tube and engaged so that its beveled edge seats against the beveled seating surface of the pipe stub by screwing the plate into the threaded pipe stub as the shaft is turned within the tube while the pin is seated in one of the recesses and may be left in place in the pipe stub by releasing the camming pin from the camming groove through the inlet slot.

  14. Large-scale chemical similarity networks for target profiling of compounds identified in cell-based chemical screens.

    PubMed

    Lo, Yu-Chen; Senese, Silvia; Li, Chien-Ming; Hu, Qiyang; Huang, Yong; Damoiseaux, Robert; Torres, Jorge Z

    2015-03-01

    Target identification is one of the most critical steps following cell-based phenotypic chemical screens aimed at identifying compounds with potential uses in cell biology and for developing novel disease therapies. Current in silico target identification methods, including chemical similarity database searches, are limited to single or sequential ligand analysis that have limited capabilities for accurate deconvolution of a large number of compounds with diverse chemical structures. Here, we present CSNAP (Chemical Similarity Network Analysis Pulldown), a new computational target identification method that utilizes chemical similarity networks for large-scale chemotype (consensus chemical pattern) recognition and drug target profiling. Our benchmark study showed that CSNAP can achieve an overall higher accuracy (>80%) of target prediction with respect to representative chemotypes in large (>200) compound sets, in comparison to the SEA approach (60-70%). Additionally, CSNAP is capable of integrating with biological knowledge-based databases (Uniprot, GO) and high-throughput biology platforms (proteomic, genetic, etc) for system-wise drug target validation. To demonstrate the utility of the CSNAP approach, we combined CSNAP's target prediction with experimental ligand evaluation to identify the major mitotic targets of hit compounds from a cell-based chemical screen and we highlight novel compounds targeting microtubules, an important cancer therapeutic target. The CSNAP method is freely available and can be accessed from the CSNAP web server (http://services.mbi.ucla.edu/CSNAP/).

  15. Large-Scale Chemical Similarity Networks for Target Profiling of Compounds Identified in Cell-Based Chemical Screens

    PubMed Central

    Lo, Yu-Chen; Senese, Silvia; Li, Chien-Ming; Hu, Qiyang; Huang, Yong; Damoiseaux, Robert; Torres, Jorge Z.

    2015-01-01

    Target identification is one of the most critical steps following cell-based phenotypic chemical screens aimed at identifying compounds with potential uses in cell biology and for developing novel disease therapies. Current in silico target identification methods, including chemical similarity database searches, are limited to single or sequential ligand analysis that have limited capabilities for accurate deconvolution of a large number of compounds with diverse chemical structures. Here, we present CSNAP (Chemical Similarity Network Analysis Pulldown), a new computational target identification method that utilizes chemical similarity networks for large-scale chemotype (consensus chemical pattern) recognition and drug target profiling. Our benchmark study showed that CSNAP can achieve an overall higher accuracy (>80%) of target prediction with respect to representative chemotypes in large (>200) compound sets, in comparison to the SEA approach (60–70%). Additionally, CSNAP is capable of integrating with biological knowledge-based databases (Uniprot, GO) and high-throughput biology platforms (proteomic, genetic, etc) for system-wise drug target validation. To demonstrate the utility of the CSNAP approach, we combined CSNAP's target prediction with experimental ligand evaluation to identify the major mitotic targets of hit compounds from a cell-based chemical screen and we highlight novel compounds targeting microtubules, an important cancer therapeutic target. The CSNAP method is freely available and can be accessed from the CSNAP web server (http://services.mbi.ucla.edu/CSNAP/). PMID:25826798

  16. Effects-based chemical category approach for prioritization of low affinity estrogenic chemicals

    EPA Science Inventory

    Regulatory agencies are charged with addressing the endocrine disrupting potential of a large number of chemicals for which there is often little or no data on which to make decisions. Prioritizing the chemicals of greatest concern for potential hazard to humans and wildlife is a...

  17. Activity based chemical proteomics: profiling proteases as drug targets.

    PubMed

    Heal, William Percy; Wickramasinghe, Sasala Roshinie; Tate, Edward William

    2008-09-01

    The pivotal role of proteases in many diseases has generated considerable interest in their basic biology, and in the potential to target them for chemotherapy. Although fundamental to the initiation and progression of diseases such as cancer, diabetes, arthritis and malaria, in many cases their precise role remains unknown. Activity-based chemical proteomics-an emerging field involving a combination of organic synthesis, biochemistry, cell biology, biophysics and bioinformatics-allows the detection, visualisation and activity quantification of whole families or selected sub-sets of proteases based upon their substrate specificity. This approach can be applied for drug target/lead identification and validation, the fundamentals of drug discovery. The activity-based probes discussed in this review contain three key features; a 'warhead' (binds irreversibly but selectively to the active site), a 'tag' (allowing enzyme 'handling', with a combination of fluorescent, affinity and/or radio labels), and a linker region between warhead and tag. From the design and synthesis of the linker arise some of the latest developments discussed here; not only can the physical properties (e.g., solubility, localisation) of the probe be tuned, but the inclusion of a cleavable moiety allows selective removal of tagged enzyme from affinity beads etc. The design and synthesis of recently reported probes is discussed, including modular assembly of highly versatile probes via solid phase synthesis. Recent applications of activity-based protein profiling to specific proteases (serine, threonine, cysteine and metalloproteases) are reviewed as are demonstrations of their use in the study of disease function in cancer and malaria.

  18. Space-Based Chemical Lasers in strategic defense

    SciTech Connect

    Wildt, D. )

    1992-07-01

    The Strategic Defense Initiative Organization (SDIO) has made significant progress in developing Space-Based chemical Laser (SBL) technologies and in studying the SBLs global defense capability. In this mission, a constellation of several orbiting laser platforms provides continuous global defense by intercepting threatening missiles in their boost phase, including short range ballistic missiles (SRBMs). An optional smaller constellation provides defense against launches from the low and midlatitude regions. In addition, SBLs have utility in other important related missions such as surveillance, air defense and discrimination. The hardware necessary to build such a system has been developed to the point where it is mature and ready for demonstration in space. Advances have been made in each of the following major areas of the SBL: laser device; optics/beam control; beam pointing; ATP (acquisition, tracking and pointing); uncooled optics; and laser lethality. Integration of the key laser and beam control technologies is now occurring in the ground-based ALI experiment, and a space demonstration experiment, Star LITE, is in the planning and concept development phase.

  19. Graphene Electronic Device Based Biosensors and Chemical Sensors

    NASA Astrophysics Data System (ADS)

    Jiang, Shan

    Two-dimensional layered materials, such as graphene and MoS2, are emerging as an exciting material system for a new generation of atomically thin electronic devices. With their ultrahigh surface to volume ratio and excellent electrical properties, 2D-layered materials hold the promise for the construction of a generation of chemical and biological sensors with unprecedented sensitivity. In my PhD thesis, I mainly focus on graphene based electronic biosensors and chemical sensors. In the first part of my thesis, I demonstrated the fabrication of graphene nanomesh (GNM), which is a graphene thin film with a periodic array of holes punctuated in it. The periodic holes introduce long periphery active edges that provide a high density of functional groups (e.g. carboxylic groups) to allow for covalent grafting of specific receptor molecules for chemical and biosensor applications. After covalently functionalizing the GNM with glucose oxidase, I managed to make a novel electronic sensor which can detect glucose as well as pH change. In the following part of my thesis I demonstrate the fabrication of graphene-hemin conjugate for nitric oxide detection. The non-covalent functionalization through pi-pi stacking interaction allows reliable immobilization of hemin molecules on graphene without damaging the graphene lattice to ensure the highly sensitive and specific detection of nitric oxide. The graphene-hemin nitric oxide sensor is capable of real-time monitoring of nitric oxide concentrations, which is of central importance for probing the diverse roles of nitric oxide in neurotransmission, cardiovascular systems, and immune responses. Our studies demonstrate that the graphene-hemin sensors can respond rapidly to nitric oxide in physiological environments with sub-nanomolar sensitivity. Furthermore, in vitro studies show that the graphene-hemin sensors can be used for the detection of nitric oxide released from macrophage cells and endothelial cells, demonstrating their

  20. Acid-base chemical mechanism of aspartase from Hafnia alvei.

    PubMed

    Yoon, M Y; Thayer-Cook, K A; Berdis, A J; Karsten, W E; Schnackerz, K D; Cook, P F

    1995-06-20

    An acid-base chemical mechanism is proposed for Hafnia alvei aspartase in which a proton is abstracted from C-3 of the monoanionic form of L-aspartate by an enzyme general base with a pK of 6.3-6.6 in the absence and presence of Mg2+. The resulting carbanion is presumably stabilized by delocalization of electrons into the beta-carboxyl with the assistance of a protonated enzyme group in the vicinity of the beta-carboxyl. Ammonia is then expelled with the assistance of a general acid group that traps an initially expelled NH3 as the final NH4+ product. In agreement with the function of the general acid group, potassium, an analog of NH4+, binds optimally when the group is unprotonated. The pK for the general acid is about 7 in the absence of Mg2+, but is increased by about a pH unit in the presence of Mg2+. Since the same pK values are observed in the pKi(succinate) and V/K pH profile, both enzyme groups must be in their optimum protonation state for efficient binding of reactant in the presence of Mg2+. At the end of a catalytic cycle, both the general base and general acid groups are in a protonation state opposite that in which they started when aspartate was bound. The presence of Mg2+ causes a pH-dependent activation of aspartase exhibited as a partial change in the V and V/Kasp pH profiles. When the aspartase reaction is run in D2O to greater than 50% completion no deuterium is found in the remaining aspartate, indicating that the site is inaccessible to solvent during the catalytic cycle.

  1. Recognition of chemical entities: combining dictionary-based and grammar-based approaches

    PubMed Central

    2015-01-01

    Background The past decade has seen an upsurge in the number of publications in chemistry. The ever-swelling volume of available documents makes it increasingly hard to extract relevant new information from such unstructured texts. The BioCreative CHEMDNER challenge invites the development of systems for the automatic recognition of chemicals in text (CEM task) and for ranking the recognized compounds at the document level (CDI task). We investigated an ensemble approach where dictionary-based named entity recognition is used along with grammar-based recognizers to extract compounds from text. We assessed the performance of ten different commercial and publicly available lexical resources using an open source indexing system (Peregrine), in combination with three different chemical compound recognizers and a set of regular expressions to recognize chemical database identifiers. The effect of different stop-word lists, case-sensitivity matching, and use of chunking information was also investigated. We focused on lexical resources that provide chemical structure information. To rank the different compounds found in a text, we used a term confidence score based on the normalized ratio of the term frequencies in chemical and non-chemical journals. Results The use of stop-word lists greatly improved the performance of the dictionary-based recognition, but there was no additional benefit from using chunking information. A combination of ChEBI and HMDB as lexical resources, the LeadMine tool for grammar-based recognition, and the regular expressions, outperformed any of the individual systems. On the test set, the F-scores were 77.8% (recall 71.2%, precision 85.8%) for the CEM task and 77.6% (recall 71.7%, precision 84.6%) for the CDI task. Missed terms were mainly due to tokenization issues, poor recognition of formulas, and term conjunctions. Conclusions We developed an ensemble system that combines dictionary-based and grammar-based approaches for chemical named

  2. A Plug and Play GNC Architecture Using FPGA Components

    NASA Technical Reports Server (NTRS)

    KrishnaKumar, K.; Kaneshige, J.; Waterman, R.; Pires, C.; Ippoloito, C.

    2005-01-01

    The goal of Plug and Play, or PnP, is to allow hardware and software components to work together automatically, without requiring manual setup procedures. As a result, new or replacement hardware can be plugged into a system and automatically configured with the appropriate resource assignments. However, in many cases it may not be practical or even feasible to physically replace hardware components. One method for handling these types of situations is through the incorporation of reconfigurable hardware such as Field Programmable Gate Arrays, or FPGAs. This paper describes a phased approach to developing a Guidance, Navigation, and Control (GNC) architecture that expands on the traditional concepts of PnP, in order to accommodate hardware reconfiguration without requiring detailed knowledge of the hardware. This is achieved by establishing a functional based interface that defines how the hardware will operate, and allow the hardware to reconfigure itself. The resulting system combines the flexibility of manipulating software components with the speed and efficiency of hardware.

  3. Effects of Distortion on Mass Flow Plug Calibration

    NASA Technical Reports Server (NTRS)

    Sasson, Jonathan; Davis, David O.; Barnhart, Paul J.

    2015-01-01

    A numerical, and experimental investigation to study the effects of flow distortion on a Mass Flow Plug (MFP) used to control and measure mass-flow during an inlet test has been conducted. The MFP was first calibrated using the WIND-US flow solver for uniform (undistorted) inflow conditions. These results are shown to compare favorably with an experimental calibration under similar conditions. The effects of distortion were investigated by imposing distorted flow conditions taken from an actual inlet test to the inflow plane of the numerical simulation. The computational fluid dynamic (CFD) based distortion study only showed the general trend in mass flow rate. The study used only total pressure as the upstream boundary condition, which was not enough to define the flow. A better simulation requires knowledge of the turbulence structure and a specific distortion pattern over a range of plug positions. It is recommended that future distortion studies utilize a rake with at least the same amount of pitot tubes as the AIP rake.

  4. Temperatures in Spark Plugs Having Steel and Brass Shells

    NASA Technical Reports Server (NTRS)

    Cragoe, C S

    1919-01-01

    This investigation was conducted at the Bureau of Standards for the National Advisory Committee for Aeronautics. Brass has often been assumed superior to steel for spark plug shells because of its greater heat conductivity. The measurements described in this report prove the contrary, showing that the interior of a spark plug having a brass shell is from 50 degrees to 150 degrees c. (90 degrees to 270 degrees f.) hotter than that of a similar steel plug. Consistent results were obtained in both an aviation and a truck engine, and under conditions which eliminated all other sources of difference between the plugs. It is to be concluded that steel is to be preferred to brass for spark plug shells. This report embodies the results of measurements taken of electrodes and a comparison of brass and steel insulators of spark plugs while they were in actual operation. The data throw considerable light upon the problem of the proper control of temperatures in these parts.

  5. Freeze plug proves safe, economical in riser repair

    SciTech Connect

    Nelson, M.J.

    1995-05-01

    In October 1992, Exxon Pipeline Co., Houston, performed in the Gulf of Mexico what the company believes to have been the first underwater freeze-plug procedure. To form a plug, water in a small section of the pipe is frozen with liquid nitrogen. In partially replacing a 10-in. riser at South Marsh Island Block 6A, Exxon Pipeline worked closely with a freeze-plug service company to minimize environmental and personnel exposure and to avoid the chance of an oil spill. The freeze plug reduced the time the pipe was open-ended during the repair, and hydrotesting the freeze plug area and repair section ensured integrity. The paper describes onshore testing of the procedures, pre-work surface cleaning, and the freeze-plug procedure.

  6. Results from the Bell Canyon borehole plugging test

    SciTech Connect

    Christensen, C. L.

    1980-01-01

    The BHP is an integrated program involving consequence assessment and plug performance calculations, materials evaluation, instrumentation development and field testing, and interfaces directly with other WIPP-related activities. This paper describes an in situ test conducted under the BHP Field Test Task. The Bell Canyon Test was conducted to evaluate candidate grout plugging mixes and plug emplacement techniques, and to assess plug performance under in-situ cure conditions. Laboratory testing of the brine-grout/rock combination revealed an adverse reaction between the brine-grout and the anhydrite. This discovery permitted a timely change to an additional laboratory compatibility testing program with an alternate fresh-water mix to permit maintenance of the test schedule with little delay. While cement emplacement technology is generally adequate to satisfy repository plugging requirements, plug compatibility with the host rock must be carefully assessed for each repository site. Generally accepted laboratory cement-testing techniques need to include flow characteristics and geochemical stability.

  7. Raman-spectroscopy-based chemical contaminant detection in milk powder

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Addition of edible and inedible chemical contaminants in food powders for purposes of economic benefit has become a recurring trend. In recent years, severe health issues have been reported due to consumption of food powders contaminated with chemical substances. This study examines the effect of sp...

  8. Exposure-Based Prioritization of Chemicals for Risk Assessment

    EPA Science Inventory

    Manufactured chemicals are used extensively to produce a wide variety of consumer goods and are required by important industrial sectors. Presently, information is insufficient to estimate risks posed to human health and the environment from the over ten thousand chemical substan...

  9. Plugging of cooling holes in film-cooled turbine vanes

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.; Lowell, C. E.

    1977-01-01

    The plugging of vane cooling holes by impurities in a marine gas turbine was closely simulated in burner rig tests where dopants were added to the combustion products of a clean fuel (Jet-A). Hole plugging occurred when liquid phases, resulting from the dopants, were present in the combustion products. Increasing flame temperature and dopant concentration resulted in an increased rate of deposition and hole plugging.

  10. Plug engine systems for future launch vehicle applications

    NASA Astrophysics Data System (ADS)

    Immich, H.; Koelle, D. E.; Parsley, R. C.

    1992-08-01

    Several feasible design options are presented for plug engine systems designed for future launch vehicle applications, including a plug nozzle engine with an annular combustion chamber, a segmented modular design, and an integration of a number of conventional engines around a common plug. The advantages and disadvantages of these options are discussed for a range of potential applications, which include single-stage-to-orbit vehicles and upper stage vehicles such as the second stage of the Saenger HTOL launch vehicle concept.

  11. Chemical and Biological Sensors Based on Organic Electrochemical Transistors

    NASA Astrophysics Data System (ADS)

    Lin, Peng

    Organic thin film transistors (OTFTs) have been explored for sensing applications for several decades due to their many advantages like easy fabrication, low cost, flexibility, and biocompatibility. Among these OTFTs, organic electrochemical transistors (OECTs) have attracted a great deal of interest in recent years since the devices can operate stably in aqueous environment with relatively low working voltages and are suitable for applications in chemical and biological sensing. In this thesis, ion-sensitive properties of OECTs based on poly(3,4- ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) have been systematically studied. It was found that the gate electrode played an important role on the ion-sensitive properties of OECTs. For the devices with Ag/AgCl gate electrode, Nernstian relationships between the shift of gate voltage and the concentrations of cations were obtained. For the devices with Pt and Au gate electrodes, the ion sensitivities were higher than that given by Nernst equation, which could be attributed to the interface between the metal gate electrode and the electrolyte. Moreover, OECTs based on PEDOT:PSS were integrated into flexible microfluidic systems. Then a novel label-free DNA sensor was developed, in which single-stranded DNA probes were immobilized on the surface of Au gate electrode. These devices successfully detected complementary DNA targets at concentrations as low as 1 nM. The detection limit was also extended to 10 pM by pulse-enhanced hybridization process of DNA. OECTs based on PEDOT:PSS were also exploited as cell-based biosensors. Human esophageal squamous epithelial cancer cell lines (KYSE30) and fibroblast cell lines (HFFI) were successfully grown on the surface of PEDOT:PSS film. Then the devices were used for in-vitro monitoring cell activities when the living cells were treated by trypsin and an anti-cancer drug, retinoic acid. It was found that the devices were sensitive to the change of surface charge

  12. CytoKavosh: a cytoscape plug-in for finding network motifs in large biological networks.

    PubMed

    Masoudi-Nejad, Ali; Ansariola, Mitra; Kashani, Zahra Razaghi Moghadam; Salehzadeh-Yazdi, Ali; Khakabimamaghani, Sahand

    2012-01-01

    Network motifs are small connected sub-graphs that have recently gathered much attention to discover structural behaviors of large and complex networks. Finding motifs with any size is one of the most important problems in complex and large networks. It needs fast and reliable algorithms and tools for achieving this purpose. CytoKavosh is one of the best choices for finding motifs with any given size in any complex network. It relies on a fast algorithm, Kavosh, which makes it faster than other existing tools. Kavosh algorithm applies some well known algorithmic features and includes tricky aspects, which make it an efficient algorithm in this field. CytoKavosh is a Cytoscape plug-in which supports us in finding motifs of given size in a network that is formerly loaded into the Cytoscape work-space (directed or undirected). High performance of CytoKavosh is achieved by dynamically linking highly optimized functions of Kavosh's C++ to the Cytoscape Java program, which makes this plug-in suitable for analyzing large biological networks. Some significant attributes of CytoKavosh is efficiency in time usage and memory and having no limitation related to the implementation in motif size. CytoKavosh is implemented in a visual environment Cytoscape that is convenient for the users to interact and create visual options to analyze the structural behavior of a network. This plug-in can work on any given network and is very simple to use and generates graphical results of discovered motifs with any required details. There is no specific Cytoscape plug-in, specific for finding the network motifs, based on original concept. So, we have introduced for the first time, CytoKavosh as the first plug-in, and we hope that this plug-in can be improved to cover other options to make it the best motif-analyzing tool.

  13. Plug-type heat flux gauge

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H. (Inventor); Koch, John, Jr. (Inventor)

    1991-01-01

    A plug-type heat flux gauge formed in a material specimen and having a thermoplug integrally formed in the material specimen, and a method for making the same are disclosed. The thermoplug is surrounded by a concentric annulus, through which thermocouple wires are routed. The end of each thermocouple wire is welded to the thermoplug, with each thermocouple wire welded at a different location along the length of the thermoplug. The thermoplug and concentric annulus may be formed in the material specimen by electrical discharge machining and trepanning procedures.

  14. Testing and plugging power plant heat exchangers

    SciTech Connect

    Sutor, F.

    1994-12-31

    Heat Exchanger tubes fail for any number of reasons including but certainly not limited to the cumulative effects of corrosion, erosion, thermal stress and fatigue. This presentation will attempt to identify the most common techniques for determining which tubes are leaking and then introduce the products in use to plug the leaking tubes. For the sake of time I will limit the scope of this presentation to include feedwater heaters and secondary system heat exchangers such as Hydrogen Coolers, Lube Oil Coolers, and nuclear Component Cooling Water, Emergency Cooling Water, Regenerative Heat Recovery heat exchangers.

  15. The sparking voltage of spark plugs

    NASA Technical Reports Server (NTRS)

    Silsbee, F B

    1925-01-01

    This report has been prepared in order to collect and correlate into convenient and useful form the available data on this subject. The importance of the subject lies in the fact that it forms the common meeting ground for studies of the performance of spark generators and spark plugs on the one hand and of the internal combustion engines on the other hand. While much of the data presented was obtained from various earlier publications, numerous places were found where necessary data were lacking, and these have been provided by experiments in gasoline engines at the Bureau of Standards.

  16. Experimental investigation of gas hydrate formation, plugging and transportability in partially dispersed and water continuous systems

    NASA Astrophysics Data System (ADS)

    Vijayamohan, Prithvi

    in water. These experiments indicate that the partially dispersed systems tend to be problematic and are more severe cases with respect to flow assurance when compared to systems where the water is completely dispersed in oil. We have found that the partially dispersed systems are distinct, and are not an intermediate case between water dominated, and water-in-oil emulsified systems. Instead the experiments indicate that the hydrate formation and plugging mechanism for these systems are very complex. Hydrate growth is very rapid for such systems when compared to 100% water cut systems. The plugging mechanism for these systems is a combination of various phenomena (wall growth, agglomeration, bedding/settling, etc). Three different oils with different viscosities have been used to investigate the transportability of hydrates with respect to oil properties. The experiments indicate that the transportability of hydrates increases with increase in oil viscosity. The data from the tests performed provide the basis for a mechanistic model for hydrate formation and plugging in partially dispersed systems. It is found that in systems that were in stratified flow regime before hydrate onset, the hydrates eventually settled on the pipe walls thereby decreasing the flow area for the flow of fluids. In systems that were in the slug flow regime before hydrate formation, moving beds of hydrates were the main cause for plugging. In both the flow regimes, the systems studied entered a plugging regime beyond a certain hydrate concentration. This is termed as φplugging onset and can be used as an indicator to calculate the amount of hydrates that can be transported safely without requiring any additional treatment for a given set of flow characteristics. A correlation to calculate this hydrate concentration based on easily accessible parameters is developed in terms of flow characteristics and oil properties. The work performed in this thesis has enhanced the understanding of the

  17. Plug Your Users into Library Resources with OpenSearch Plug-Ins

    ERIC Educational Resources Information Center

    Baker, Nicholas C.

    2007-01-01

    To bring the library catalog and other online resources right into users' workspace quickly and easily without needing much more than a short XML file, the author, a reference and Web services librarian at Williams College, learned to build and use OpenSearch plug-ins. OpenSearch is a set of simple technologies and standards that allows the…

  18. Chemical sensors based on micromachined transducers with integrated piezoresistive readout.

    PubMed

    Potyrailo, Radislav A; Leach, Andrew; Morris, William G; Gamage, Sisira Kankanam

    2006-08-15

    We demonstrate an approach for the development of chemical sensors utilizing silicon micromachined physical transducers with integrated piezoresistive readout. Originally, these transducers were developed and optimized as sensitive accelerometers for automotive applications. However, by applying a chemically responsive layer onto the transducer, we convert these transducers into chemical sensors. These transducers are attractive for chemical sensing applications for several key reasons. First, the required sensitivity of the chemical sensor can be achieved by choosing the right spring constant of the transducer. Second, the integrated piezoresistive readout of the transducer is already optimized and is very straightforward, providing a desired reproducibility in measurements, while not requiring bulky equipment. Third, chemically responsive film deposition is simple due to the ease of access to the transducer's surface. Fourth, such transducers are already available for another (automotive) application, making these sensors very cost-effective. The applicability of this approach is illustrated by the fabrication of highly sensitive CO2 sensors. To study hysteresis effects, we selected high CO2 concentrations (10-100% CO2) to provide the worst-case scenario for the sensor operation. These sensors demonstrate a hysteresis-free performance over the concentration range from 10 to 100% vol CO2, have detection limits of 160-370 ppm of CO2, and exhibit a relatively rapid response time, T(90) = 45 s. Importantly, we demonstrate a simple method for cancellation of vibration effects when these physical transducers, initially developed as accelerometers, are applied as chemical sensors. PMID:16906705

  19. Homoeologous relationship of rye chromosome arms as detected with wheat PLUG markers.

    PubMed

    Li, Jianjian; Endo, Takashi R; Saito, Mika; Ishikawa, Goro; Nakamura, Toshiki; Nasuda, Shuhei

    2013-12-01

    Based on the similarity in gene structure between rice and wheat, the polymerase chain reaction (PCR)-based landmark unique gene (PLUG) system enabled us to design primer sets that amplify wheat genic sequences including introns. From the previously reported wheat PLUG markers, we chose 144 markers that are distributed on different chromosomes and in known chromosomal regions (bins) to obtain rye-specific PCR-based markers. We conducted PCR with the 144 primer sets and the template of the Imperial rye genomic DNA and found that 131 (91.0%) primer sets successfully amplified PCR products. Of the 131 PLUG markers, 110 (76.4%) markers showed rye-specific PCR amplification with or without restriction enzyme digestion. We assigned 79 of the 110 markers to seven rye chromosomes (1R to 7R) using seven wheat-rye (cv. Imperial) chromosome addition and substitution lines: 12 to 1R, 8 to 2R, 11 to 3R, 8 to 4R, 16 to 5R, 12 to 6R, and 12 to 7R. Furthermore, we located their positions on the short or long (L) chromosome arm, using 13 Imperial rye telosomic lines of common wheat (except for 3RL). Referring to the chromosome bin locations of the 79 PLUG markers in wheat, we deduced the syntenic relationships between rye and wheat chromosomes. We also discussed chromosomal rearrangements in the rye genome with reference to the cytologically visible chromosomal gaps.

  20. Recommended analysis plan for the borehole plugging program potash core test

    SciTech Connect

    Lambert, S. J.

    1980-05-01

    A four-year old plugged potash core hole near the Waste Isolation Pilot Plant (WIPP) site in southeastern New Mexico has been proposed for overcoring, in order to examine the behavior of known grout mix constituents in contact with a variety of rock types during an extended grout-curing interval. This report recommends that various geochemical analyses be applied to the core samples containing both grout and rock and the interface between the two. The methods to be used include optical petrography, electron microscopy, electron probe microanalysis, x-ray diffraction, thermal analysis (TGA, DSC, DTA) with gas chromatography/mass spectrometry, and bulk chemical analysis. These analyses would allow identification of phases which have developed during grout curing, and provide evidence of reactions which may have taken place among constituents in the system grout-rock-groundwater. These reactions, and their sequence of occurrence will be compared with reactions predicted by thermodynamic modeling as the system seeks its lowest Gibbs' free energy. Identification of reactions which have the potential for compromising the integrity of a grout plug will receive special attention. Since not all such detrimental reactions can be observed directly in a human lifetime, due to kinetic inhibitions, and since a capability of time-dependent prediction of their degree of occurrence cannot be developed, thermodynamic modeling is the only known way of evaluating the long-term stability of a grout plug. The analysis of the plug-rock system will give an indication of in situ curing history of grout plug, and will allow an early occurrence of potentially detrimental reactions to be detected. Thus, this activity will be a case-study of suitability of certain grout mixtures for use in evaporites, as an example of evaluation of grouts for long-term compatability with a variety of rock types.

  1. Comparative Analysis of QSAR-based vs. Chemical Similarity Based Predictors of GPCRs Binding Affinity.

    PubMed

    Luo, Man; Wang, Xiang S; Tropsha, Alexander

    2016-01-01

    Ligand based virtual screening (LBVS) approaches could be broadly divided into those relying on chemical similarity searches and those employing Quantitative Structure-Activity Relationship (QSAR) models. We have compared the predictive power of these approaches using some datasets of compounds tested against several G-Protein Coupled Receptors (GPCRs). The k-Nearest Neighbors (kNN) QSAR models were built for known ligands of each GPCR target independently, with a fraction of tested ligands for each target set aside as a validation set. The prediction accuracies of QSAR models for making active/inactive calls for compounds in both training and validation sets were compared to those achieved by the Prediction of Activity Spectra for Substances' (PASS) and the Similarity Ensemble Approach (SEA) tools both available online. Models developed with the kNN QSAR method showed the highest predictive power for almost all tested GPCR datasets. The PASS software, which incorporates multiple end-point specific QSAR models demonstrated a moderate predictive power, while SEA, a chemical similarity based approach, had the lowest prediction power. Our studies suggest that when sufficient amount of data is available to develop and rigorously validate QSAR models such models should be chosen as the preferred virtual screening tool in ligand-based computational drug discovery as compared to chemical similarity based approaches. PMID:27491652

  2. Evaluation of a chemical munition dumpsite in the Baltic Sea based on geophysical and chemical investigations.

    PubMed

    Missiaen, Tine; Söderström, Martin; Popescu, Irina; Vanninen, Paula

    2010-08-01

    This paper discusses the results of geophysical and chemical investigations carried out in a chemical munition dumpsite in the southern Baltic Sea, east of the island of Bornholm. After WW2 over 32,000 tons of chemical war material was dumped here including shells and bombs as well as small drums and containers. The geophysical investigations combined very-high-resolution seismics and gradiometric measurements. The results indicate the presence of a large number of objects buried just below the seafloor. The size of the objects and their distribution, with a marked increase in density towards the center of the dumpsite, suggests that we are dealing with dumped war material. Sediment and near-bottom water samples, taken within the dumpsite and in the surrounding area, were analysed for the presence of various chemical warfare agents (CWA) including Adamsite, Clark, sulphur mustard, tabun, chlorobenzene and arsine oil. The results indicate a widespread contamination that reaches far beyond the dumpsite boundary. CWA degradation products were found in most of the sediment samples. The contamination was mostly related to arsenic containing compounds; only one sample indicated the presence of sulfur mustard. Although the correlation between detected objects and CWA concentrations is not always straightforward, the overall results suggest that a lot of the dumped war material is leaking and that over the years the contamination has reached the seafloor sediments. PMID:20593551

  3. Assessing the Robustness of Chemical Prioritizations Based on ToxCast Chemical Profiling

    EPA Science Inventory

    A central goal of the U.S. EPA’s ToxCast™ program is to provide empirical, scientific evidence to aid in prioritizing the toxicity testing of thousands of chemicals. The agency has developed a prioritization approach, the Toxicological Prioritization Index (ToxPi™), that calculat...

  4. Impedimetric immunoglobulin G immunosensor based on chemically modified graphenes

    NASA Astrophysics Data System (ADS)

    Loo, Adeline Huiling; Bonanni, Alessandra; Ambrosi, Adriano; Poh, Hwee Ling; Pumera, Martin

    2012-01-01

    Immunosensors which display high sensitivity and selectivity are of utmost importance to the biomedical field. Graphene is a material which has immense potential for the fabrication of immunosensors. For the first time, we evaluate the immunosensing capabilities of various graphene surfaces in this work. We propose a simple and label-free electrochemical impedimetric immunosensor for immunoglobulin G (IgG) based on chemically modified graphene (CMG) surfaces such as graphite oxide, graphene oxide, thermally reduced graphene oxide and electrochemically reduced graphene oxide. Disposable electrochemical printed electrodes were first modified with CMG materials before anti-immunoglobulin G (anti-IgG), which is specific to IgG, was immobilized. The principle of detection lies in the changes in impedance spectra of the redox probe after the attachment of IgG to the immobilized anti-IgG. It was found that thermally reduced graphene oxide has the best performance when compared to the other CMG materials. In addition, the optimal concentration of anti-IgG to be deposited onto the modified electrode surface is 10 μg ml-1 and the linear range of detection of the immunosensor is from 0.3 μg ml-1 to 7 μg ml-1. Finally, the fabricated immunosensor also displays selectivity for IgG.Immunosensors which display high sensitivity and selectivity are of utmost importance to the biomedical field. Graphene is a material which has immense potential for the fabrication of immunosensors. For the first time, we evaluate the immunosensing capabilities of various graphene surfaces in this work. We propose a simple and label-free electrochemical impedimetric immunosensor for immunoglobulin G (IgG) based on chemically modified graphene (CMG) surfaces such as graphite oxide, graphene oxide, thermally reduced graphene oxide and electrochemically reduced graphene oxide. Disposable electrochemical printed electrodes were first modified with CMG materials before anti-immunoglobulin G (anti

  5. MODELLING THE UPTAKE AND DISPOSITION OF HYDROPHOBIC ORGANIC CHEMICALS IN FISH USING A PHYSIOLOGICALLY BASED APPROACH

    EPA Science Inventory

    The development of physiologically based toxicokinetic (PBTK) models for hydrophobic chemicals in fish requires: 1) an understanding of chemical efflux at fish gills; 2) knowledge of the factors that limit chemical exchange between blood and tissues; and, 3) a mechanistic descrip...

  6. Chemical Sensors Based On Oxygen Detection By Optical Methods

    NASA Astrophysics Data System (ADS)

    Parker, Jennifer W.; Cox, M. E.; Dunn, Bruce S.

    1986-08-01

    Fluorescence quenching is shown to be a viable method of measuring oxygen concentration. Two oxygen/optical transducers based on fluorescence quenching have been developed and characterized: one is hydrophobic and the other is hydrophilic. The development of both transducers provides great flexibility in the application of fluorescence to oxygen measurement. One transducer is produced by entrapping a fluorophor, 9,10-diphenyl anthracene, in poly(dimethyl siloxane) to yield a homogeneous composite polymer matrix. The resulting matrix is hydrophobic. This transducer is extremely sensitive to PO2 as a result of oxygen quenching the fluorescence of 9,10-diphenyl anthracene. This quenching is utilized in the novel method employed to measure the transport properties of oxygen within Ulf 2matrix. Results show large values for the diffusion coefficient at 25°C, D = 3.5 x 10-5 cm /s. The fluorescence intensity varies inversely with P02. The second oxygen transducer is fabricated by entrapping 9,10-diphenyl anthracene in poly(hydroxy ethyl methacrylate). Free radical, room temperature polymerization is employed. This transducer is hydrophilic, and contains 37% water. The transport properties of oxygen within this transducer are compared with those of the hydrophobic transducer. The feasibility of generalizing the oxygen transducers to a wider class of chemical sensors through coupling to other chemistries is proposed. An example of such coupling is given in a glucose/oxygen transducer. The glucose transducer is produced by entrapping an enzyme, glucose oxidase, in the composite matrix of the hydrophilic oxygen transducer. Glucose oxidase catalyzes a reaction between glucose and oxygen, thereby lowering the local oxygen concentration. This transducer yields a glucose modified optical oxygen signal. The operation of this transducer and preliminary results of its characterization are presented.

  7. Deep Space Habitat Wireless Smart Plug

    NASA Technical Reports Server (NTRS)

    Morgan, Joseph A.; Porter, Jay; Rojdev, Kristina; Carrejo, Daniel B.; Colozza, Anthony J.

    2014-01-01

    NASA has been interested in technology development for deep space exploration, and one avenue of developing these technologies is via the eXploration Habitat (X-Hab) Academic Innovation Challenge. In 2013, NASA's Deep Space Habitat (DSH) project was in need of sensors that could monitor the power consumption of various devices in the habitat with added capability to control the power to these devices for load shedding in emergency situations. Texas A&M University's Electronic Systems Engineering Technology Program (ESET) in conjunction with their Mobile Integrated Solutions Laboratory (MISL) accepted this challenge, and over the course of 2013, several undergraduate students in a Capstone design course developed five wireless DC Smart Plugs for NASA. The wireless DC Smart Plugs developed by Texas A&M in conjunction with NASA's Deep Space Habitat team is a first step in developing wireless instrumentation for future flight hardware. This paper will further discuss the X-Hab challenge and requirements set out by NASA, the detailed design and testing performed by Texas A&M, challenges faced by the team and lessons learned, and potential future work on this design.

  8. Evaluation of a biomimetic optical-filter based chemical sensor for detection of hazardous chemical vapors in the infrared

    NASA Astrophysics Data System (ADS)

    Major, Kevin J.; Poutous, Menelaos K.; Dunnill, Kevin F.; Ewing, Kenneth J.; Sanghera, Jasbinder S.; Deguzman, P. C.; Aggarwal, Ishwar D.

    2016-05-01

    Detection of concealed hazardous materials is a pressing need for the global defense community. To address this need, the development of reliable and readily-deployable sensing devices is a key area of research. A multitude of infrared sensing techniques are being studied which allow for reliable sensing of concealed threats. Continued development in this field is working to increase the selectivity of such infrared sensors, while at the same time reducing their complexity, size and cost. We have recently developed a biomimetic optical filter based approach, based on human color vision, that utilizes multiple, broadband, overlapping infrared (IR) filters to clearly discriminate between hazardous target chemicals and interferents with very similar mid-IR spectral signatures. This technique was extensively studied in order to select filters which provide optimum selectivity for specific chemical sets. Using this knowledge, we designed and assembled a gas-phase sensor which uses three broadband mid-IR filters to detect and discriminate between a target chemical, fuel oil, and various interferents with strongly overlapping IR absorption bands in the carbon - hydrogen stretch region of the IR absorption spectrum 2700 cm-1 - 3300 cm-1 (3.0 μm - 3.7 μm). We present an overview of the design and performance of this filter-based system and explore the ability of this system to detect and discriminate between strongly overlapping target and interferent chemicals. The detection results using the filter-based system are compared to numerical methods to demonstrate the operation of this methodology. We present the results of experiments with both target and interferent chemicals present with chemicals both in and out of the detection set, and discuss future field development and application of this approach.

  9. Biomass plug development and propagation in porous media.

    PubMed

    Stewart, T L; Fogler, H S

    2001-02-01

    Exopolymer-producing bacteria can be used to modify soil profiles for enhanced oil recovery or bioremediation. Understanding the mechanisms associated with biomass plug development and propagation is needed for successful application of this technology. These mechanisms were determined from packed-bed and micromodel experiments that simulate plugging in porous media. Leuconostoc mesenteroides was used, because production of dextran, a water-insoluble exopolymer, can be controlled by using different carbon sources. As dextran was produced, the pressure drop across the porous media increased and began to oscillate. Three pressure phases were identified under exopolymer-producing conditions: the exopolymer-induction phase, the plugging phase, and the plug-propagation phase. The exopolymer-induction phase extended from the time that exopolymer-producing conditions were induced until there was a measurable increase in pressure drop across the porous media. The plugging phase extended from the first increase in pressure drop until a maximum pressure drop was reached. Changes in pressure drop in these two phases were directly related to biomass distribution. Specifically, flow channels within the porous media filled with biomass creating a plugged region where convective flow occurred only in water channels within the biofilm. These water channels were more restrictive to flow causing the pressure drop to increase. At a maximum pressure drop across the porous media, the biomass yielded much like a Bingham plastic, and a flow channel was formed. This behavior marked the onset of the plug-propagation phase which was characterized by sequential development and breakthrough of biomass plugs. This development and breakthrough propagated the biomass plug in the direction of nutrient flow. The dominant mechanism associated with all three phases of plugging in porous media was exopolymer production; yield stress is an additional mechanism in the plug-propagation phase. PMID

  10. Prevalence and Characteristics of Chemical Intolerance: A Japanese Population-Based Study.

    PubMed

    Azuma, Kenichi; Uchiyama, Iwao; Katoh, Takahiko; Ogata, Hiromitsu; Arashidani, Keiichi; Kunugita, Naoki

    2015-01-01

    Population-based cross-sectional study was performed to estimate the prevalence of chemical intolerance and to examine the characteristics of the sample. A Web-based survey was conducted that included 7,245 adults in Japan. The criteria for chemical intolerance proposed by Skovbjerg yielded a prevalence of 7.5% that was approximately consistent with that reported from a Danish population-based survey. Female gender, older age, and renovation in the house during the past 7 years were positively associated with chemical intolerance. Improvements in the condition were observed with daily ventilation habits. Medical history of atopic dermatitis, allergic rhinitis, food allergy, multiple chemical sensitivity, and depression were associated with chemical intolerance. Fatigue, depressed mood, and somatic symptoms were also positively correlated with chemical intolerance. Better elucidation of the causes, comorbidities, concomitants, and consequences of chemical intolerance has the potential to provide effective solutions for its prevention and treatment. PMID:25137616

  11. Development of a software platform for a plug-in hybrid electric vehicle simulator

    NASA Astrophysics Data System (ADS)

    Karlis, Athanasios D.; Bibeau, Eric; Zanetel, Paul; Lye, Zelon

    2012-03-01

    Electricity use for transportation has had limited applications because of battery storage range issues, although many recent successful demonstrations of electric vehicles have been achieved. Renewable biofuels such as biodiesel and bioethanol also contribute only a small percentage of the overall energy mix for mobility. Recent advances in hybrid technologies have significantly increased vehicle efficiencies. More importantly, hybridization now allows a significant reduction in battery capacity requirements compared to pure electric vehicles, allowing electricity to be used in the overall energy mix in the transportation sector. This paper presents an effort made to develop a Plug-in Hybrid Electric Vehicle (PHEV) platform that can act as a comprehensive alternative energy vehicle simulator. Its goal is to help in solving the pressing needs of the transportation sector, both in terms of contributing data to aid policy decisions for reducing fossil fuel use, and to support research in this important area. The Simulator will allow analysing different vehicle configurations, and control strategies with regards to renewable and non-renewable fuel and electricity sources. The simulation platform models the fundamental aspects of PHEV components, that is, process control, heat transfer, chemical reactions, thermodynamics and fluid properties. The outcomes of the Simulator are: (i) determining the optimal combination of fuels and grid electricity use, (ii) performing greenhouse gas calculations based on emerging protocols being developed, and (iii) optimizing the efficient and proper use of renewable energy sources in a carbon constrained world.

  12. Chemical-chemical interaction between cyanogenic toxicants and aldehydes: a mechanism-based QSAR approach to assess toxicological joint effects.

    PubMed

    Lin, Z; Wei, D; Wang, X; Yin, K; Zhao, D

    2004-04-01

    A QSAR approach was proposed to assess toxicological joint effects based on the mechanism of chemical-chemical interactions between cyanogenic toxicants and aldehydes. It has been observed that the chemical-chemical interaction between cyanogenic toxicants and aldehydes resulted in the formation of carbanion intermediates, and therefore this interaction led to different toxicological joint effects between cyanogenic toxicants and aldehydes. Analysis of this chemical-chemical interaction showed that the formation of carbanion intermediate highly depended on the charge of the carbon atom in the -CHO of aldehydes and this of the carbon atom (C*) in the carbochain of cyanogenic toxicant. By using the Hammett Constant (sigma(p)) to measure the charge of carbon atom in the -CHO of aldehydes, a mechanism-based QSAR approach (M = 0.316 - 4.386sigma(p) with r2 = 0.933, SE = 0.082, F = 55.389, p = 0.002, M = sum of toxic units) was proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aliphatic aldehydes. Another one (M = 0.978 - 0.720sigma(p) with r2 = 0.852, SE = 0.152, F = 40.148, p = 0.0001) was also proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aromatic aldehydes. Lastly, by using the charge of carbon atom (C*) in the carbochain of cyanogenic toxicant, a mechanism-based QSAR model (M = -0.161 - 7.721C* with r2 = 0.847, SE = 0.227, F = 27.657, p = 0.003) was derived to assess toxicological joint effects between p-nitrobenzaldehyde and cyanogenic toxicants.

  13. Battery Test Manual For Plug-In Hybrid Electric Vehicles

    SciTech Connect

    Jeffrey R. Belt

    2010-09-01

    This battery test procedure manual was prepared for the United States Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Program. It is based on technical targets established for energy storage development projects aimed at meeting system level DOE goals for Plug-in Hybrid Electric Vehicles (PHEV). The specific procedures defined in this manual support the performance and life characterization of advanced battery devices under development for PHEV’s. However, it does share some methods described in the previously published battery test manual for power-assist hybrid electric vehicles. Due to the complexity of some of the procedures and supporting analysis, a revision including some modifications and clarifications of these procedures is expected. As in previous battery and capacitor test manuals, this version of the manual defines testing methods for full-size battery systems, along with provisions for scaling these tests for modules, cells or other subscale level devices.

  14. Battery Test Manual For Plug-In Hybrid Electric Vehicles

    SciTech Connect

    Jeffrey R. Belt

    2010-12-01

    This battery test procedure manual was prepared for the United States Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Program. It is based on technical targets established for energy storage development projects aimed at meeting system level DOE goals for Plug-in Hybrid Electric Vehicles (PHEV). The specific procedures defined in this manual support the performance and life characterization of advanced battery devices under development for PHEV’s. However, it does share some methods described in the previously published battery test manual for power-assist hybrid electric vehicles. Due to the complexity of some of the procedures and supporting analysis, a revision including some modifications and clarifications of these procedures is expected. As in previous battery and capacitor test manuals, this version of the manual defines testing methods for full-size battery systems, along with provisions for scaling these tests for modules, cells or other subscale level devices.

  15. Control of resistance plug welding using quantitative feedback theory

    SciTech Connect

    Bentley, A.E.; Horowitz, I. ||; Chait, Y.; Rodrigues, J.

    1996-12-01

    Resistance welding is used extensively throughout the manufacturing industry. Variations in weld quality often result in costly post-weld inspections. Applications of feed-back control to such processes have been limited by the lack of accurate models describing the nonlinear dynamics of this process. A new system based on electrode displacement feedback is developed that greatly improves quality control of the resistance plug welding process. The system is capable of producing repeatable welds of consistent displacement (and thus consistent quality), with wide variations in weld parameters. This paper describes the feedback design of a robust controller using Quantitative Feedback Theory for this highly complex process, and the experimental results of the applied system.

  16. Plug-in hybrid electric vehicles in smart grid

    NASA Astrophysics Data System (ADS)

    Yao, Yin

    In this thesis, in order to investigate the impact of charging load from plug-in hybrid electric vehicles (PHEVs), a stochastic model is developed in Matlab. In this model, two main types of PHEVs are defined: public transportation vehicles and private vehicles. Different charging time schedule, charging speed and battery capacity are considered for each type of vehicles. The simulation results reveal that there will be two load peaks (at noon and in evening) when the penetration level of PHEVs increases continuously to 30% in 2030. Therefore, optimization tool is utilized to shift load peaks. This optimization process is based on real time pricing and wind power output data. With the help of smart grid, power allocated to each vehicle could be controlled. As a result, this optimization could fulfill the goal of shifting load peaks to valley areas where real time price is low or wind output is high.

  17. Expandable rubber plug seals openings for pressure testing

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Plug assembly seals openings in piping systems, vessels, and chambers for low pressure leak testing. The assembly, which consists of a rubber sealing plug and the mechanism for expanding it into a pressure-tight configuration, adequately seals irregular diameters without damage to mating surfaces.

  18. Dual Spark Plugs For Stratified-Charge Rotary Engine

    NASA Technical Reports Server (NTRS)

    Abraham, John; Bracco, Frediano V.

    1996-01-01

    Fuel efficiency of stratified-charge, rotary, internal-combustion engine increased by improved design featuring dual spark plugs. Second spark plug ignites fuel on upstream side of main fuel injector; enabling faster burning and more nearly complete utilization of fuel.

  19. 40 CFR 147.2905 - Plugging and abandonment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Plugging and abandonment. 147.2905 Section 147.2905 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS...-Class II Wells § 147.2905 Plugging and abandonment. The owner/operator shall notify the Osage UIC...

  20. 40 CFR 147.3105 - Plugging and abandonment report.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Plugging and abandonment report. 147.3105 Section 147.3105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Certain Oklahoma Indian Tribes § 147.3105 Plugging and abandonment report. (a) In lieu of the time...

  1. 40 CFR 147.2905 - Plugging and abandonment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Plugging and abandonment. 147.2905 Section 147.2905 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS...-Class II Wells § 147.2905 Plugging and abandonment. The owner/operator shall notify the Osage UIC...

  2. 40 CFR 147.3105 - Plugging and abandonment report.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Plugging and abandonment report. 147.3105 Section 147.3105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Certain Oklahoma Indian Tribes § 147.3105 Plugging and abandonment report. (a) In lieu of the time...

  3. 40 CFR 147.3105 - Plugging and abandonment report.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Plugging and abandonment report. 147.3105 Section 147.3105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Certain Oklahoma Indian Tribes § 147.3105 Plugging and abandonment report. (a) In lieu of the time...

  4. 40 CFR 147.3105 - Plugging and abandonment report.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Plugging and abandonment report. 147.3105 Section 147.3105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Certain Oklahoma Indian Tribes § 147.3105 Plugging and abandonment report. (a) In lieu of the time...

  5. 40 CFR 147.3105 - Plugging and abandonment report.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Plugging and abandonment report. 147.3105 Section 147.3105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Certain Oklahoma Indian Tribes § 147.3105 Plugging and abandonment report. (a) In lieu of the time...

  6. 40 CFR 147.2905 - Plugging and abandonment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Plugging and abandonment. 147.2905 Section 147.2905 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS...-Class II Wells § 147.2905 Plugging and abandonment. The owner/operator shall notify the Osage UIC...

  7. Hybrid and Plug-In Electric Vehicles (Brochure)

    SciTech Connect

    Not Available

    2014-05-01

    Hybrid and plug-in electric vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), all-electric vehicles (EVs). Together, they have great potential to cut U.S. petroleum use and vehicle emissions.

  8. California Statewide Plug-In Electric Vehicle Infrastructure Assessment

    SciTech Connect

    Melaina, Marc; Helwig, Michael

    2014-05-01

    The California Statewide Plug-In Electric Vehicle Infrastructure Assessment conveys to interested parties the Energy Commission’s conclusions, recommendations, and intentions with respect to plug-in electric vehicle (PEV) infrastructure development. There are several relatively low-risk and high-priority electric vehicle supply equipment (EVSE) deployment options that will encourage PEV sales and

  9. Electrically heated particulate matter filter with recessed inlet end plugs

    DOEpatents

    Gonze, Eugene V.; Ament, Frank

    2012-02-21

    A particulate matter (PM) filter includes filter walls having inlet ends and outlet ends. First adjacent pairs of the filter walls define inlet channels. Second adjacent pairs of the filter walls define outlet channels. Outlet end plugs are arranged in the inlet channels adjacent to the output ends. Inlet end plugs arranged in the outlet channels spaced from the inlet ends.

  10. The Losing Battle against Plug-and-Chug

    ERIC Educational Resources Information Center

    Kortemeyer, Gerd

    2016-01-01

    I think most physics teachers would agree that two important components of a proper solution to a numerical physics problem are to first figure out a final symbolic solution and to only plug in numbers in the end. However, in spite of our best efforts, this is not what the majority of students is actually doing. Instead, they tend to plug numbers…

  11. Properties and preparation of ceramic insulators for spark plugs

    NASA Technical Reports Server (NTRS)

    Silsbee, F B; Honaman, R K; Fonseca, E L; Bleininger, A V; Staley, H F

    1920-01-01

    Report describes in detail the preliminary experiments which were made on the conductivity of spark-plug insulators in order to develop a satisfactory comparative method for testing various spark-plug materials. Materials tested were cements, porcelain, feldspar, and quartz.

  12. Rapid retraction of microvolume aqueous plugs traveling in a wettable capillary

    NASA Astrophysics Data System (ADS)

    Kim, Jinho; O'Neill, John D.; Vunjak-Novakovic, Gordana

    2015-10-01

    We report a transport behavior—specifically, rapid retraction movement—of small (˜μL) deionized water plugs traveling in series within a small wettable tubular geometry. In this study, two water plugs separated by a certain distance in a dry cylindrical glass capillary were moved by positive pressure airflow applied at the tube inlet. As the plugs travel, a thin aqueous film is generated between the plugs as a result of the leading plug's aqueous deposition onto the inner surface of the tube. The leading plug continuously loses volume by film deposition onto the surface and eventually ruptures. Then, the lagging plug quickly travels the distance initially separating the two plugs (plug retraction). Our studies show that the rapid retraction of the lagging plug is caused by surface tension in addition to the positive pressure applied. Furthermore, the plug retraction speed is strongly affected by tube radius and the distance between the plugs.

  13. A Case of Randall's Plugs Associated to Calcium Oxalate Dihydrate Calculi.

    PubMed

    Grases, Felix; Söhnel, Otakar; Costa-Bauza, Antonia; Servera, Antonio; Benejam, Juan

    2016-07-01

    A case of a patient who developed multiple calcium oxalate dihydrate calculi, some of them connected to intratubular calcifications (Randall's plugs), is presented. Randall's plugs were isolated and studied. The mechanism of Randall's plug development is also suggested. PMID:27335788

  14. SmartBuild-a truly plug-n-play modular microfluidic system.

    PubMed

    Yuen, Po Ki

    2008-08-01

    In this Technical Note, for the first time, a truly "plug-n-play" modular microfluidic system (SmartBuild Plug-n-Play Modular Microfluidic System) is presented for designing and building integrated modular microfluidic systems for biological and chemical applications. The modular microfluidic system can be built by connecting multiple microfluidic components together to form a larger integrated system. The SmartBuild System comprises of a motherboard with interconnect channels/grooves, fitting components, microchannel inserts with different configurations and microchips/modules with different functionalities. Also, heaters, micropumps and valving systems can be designed and used in the system. Examples of an integrated mixing system and reaction systems are presented here to demonstrate the versatility of the SmartBuild System. PMID:18651081

  15. My contribution to broadening the base of chemical engineering.

    PubMed

    Sargent, Roger W H

    2011-01-01

    This paper is a short account, from a personal viewpoint, of the various contributions I have made to expand the academic basis of chemical engineering from its origin in the unifying concept of unit operations, focussed on process design, to encompassing all the professional activities of industrial chemical engineers. This includes all aspects of planning and scheduling the operations as well as designing and controlling the process plant. The span of my career also happens to include the birth of the age of computing, with all the consequential implications.

  16. Photopolymerization-based fabrication of chemical sensing films

    DOEpatents

    Yang, Xiaoguang; Swanson, Basil I.; Du, Xian-Xian

    2003-12-30

    A photopolymerization method is disclosed for attaching a chemical microsensor film to an oxide surface including the steps of pretreating the oxide surface to form a functionalized surface, coating the functionalized surface with a prepolymer solution, and polymerizing the prepolymer solution with ultraviolet light to form the chemical microsensor film. The method also allows the formation of molecular imprinted films by photopolymerization. Formation of multilayer sensing films and patterned films is allowed by the use of photomasking techniques to allow patterning of multiple regions of a selected sensing film, or creating a sensor surface containing several films designed to detect different compounds.

  17. Unified theory on the pathogenesis of Randall's plaques and plugs.

    PubMed

    Khan, Saeed R; Canales, Benjamin K

    2015-01-01

    Kidney stones develop attached to sub-epithelial plaques of calcium phosphate (CaP) crystals (termed Randall's plaque) and/or form as a result of occlusion of the openings of the Ducts of Bellini by stone-forming crystals (Randall's plugs). These plaques and plugs eventually extrude into the urinary space, acting as a nidus for crystal overgrowth and stone formation. To better understand these regulatory mechanisms and the pathophysiology of idiopathic calcium stone disease, this review provides in-depth descriptions of the morphology and potential origins of these plaques and plugs, summarizes existing animal models of renal papillary interstitial deposits, and describes factors that are believed to regulate plaque formation and calcium overgrowth. Based on evidence provided within this review and from the vascular calcification literature, we propose a "unified" theory of plaque formation-one similar to pathological biomineralization observed elsewhere in the body. Abnormal urinary conditions (hypercalciuria, hyperoxaluria, and hypocitraturia), renal stress or trauma, and perhaps even the normal aging process lead to transformation of renal epithelial cells into an osteoblastic phenotype. With this de-differentiation comes an increased production of bone-specific proteins (i.e., osteopontin), a reduction in crystallization inhibitors (such as fetuin and matrix Gla protein), and creation of matrix vesicles, which support nucleation of CaP crystals. These small deposits promote aggregation and calcification of surrounding collagen. Mineralization continues by calcification of membranous cellular degradation products and other fibers until the plaque reaches the papillary epithelium. Through the activity of matrix metalloproteinases or perhaps by brute physical force produced by the large sub-epithelial crystalline mass, the surface is breached and further stone growth occurs by organic matrix-associated nucleation of CaOx or by the transformation of the outer layer

  18. Bio-based production of C2-C6 platform chemicals.

    PubMed

    Jang, Yu-Sin; Kim, Byoungjin; Shin, Jae Ho; Choi, Yong Jun; Choi, Sol; Song, Chan Woo; Lee, Joungmin; Park, Hye Gwon; Lee, Sang Yup

    2012-10-01

    Platform chemicals composed of 2-6 carbons derived from fossil resources are used as important precursors for making a variety of chemicals and materials, including solvents, fuels, polymers, pharmaceuticals, perfumes, and foods. Due to concerns regarding our environment and the limited nature of fossil resources, however, increasing interest has focused on the development of sustainable technologies for producing these platform chemicals from renewable resources. The techniques and strategies for developing microbial strains for chemicals production have advanced rapidly, and it is becoming feasible to develop microbes for producing additional types of chemicals, including non-natural molecules. In this study, we review the current status of the bio-based production of major C2-C6 platform chemicals, focusing on the microbial production of platform chemicals that have been used for the production of chemical intermediates, building block compounds, and polymers.

  19. Pharmacokinetically based mapping device for chemical space navigation.

    PubMed

    Oprea, Tudor I; Zamora, Ismael; Ungell, Anna-Lena

    2002-01-01

    ChemGPS, the chemical global positioning system, is a tool that combines rules (equivalent to dimensions) and objects (chemical structures) to provide a consistent chemical space map (Oprea, T. I.; Gottfries, J. J. Comb. Chem. 2001, 3, 157-166.). Rules included, initially, general properties such as size, lipophilicity, and hydrogen bond capacity, while objects include "satellites", intentionally placed outside the druglike space, as well as "core" objects, mostly orally available drugs. ChemGPS molecules (objects) were used in conjunction with the VolSurf (http://www.moldiscovery.com) descriptors (rules), which are relevant for ADME (absorption, distribution, metabolism, and excretion) properties. The combination of ChemGPS and VolSurf, GPSVS, was investigated with respect to the biopharmaceutics classification system, which is recommended by the Food and Drug Administration (FDA) (http://www.fda.gov/cder/OPS/BCS_guidance.htm), in particular with respect to permeability and solubility. The first GPSVS principal component correlates, with no further training, to passive transcellular permeability, as illustrated for the Caco-2, ghost erythrocyte, and blood-brain barrier datasets, respectively. The second GPSVS principal component correlates, without prior training, to solubility, as shown for the octanol-water partition and intrinsic solubility datasets, respectively. Although derived from principal component analysis, the two property axes rotate and form an angle of approximately 43 degrees, thus being no longer orthogonal. GPSVS can be used to map the chemical space with respect to permeability and solubility, as recommended by FDA's biopharmaceutics classification system. PMID:12099842

  20. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    EPA Science Inventory

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient d...

  1. Ex Priori: Exposure-based Prioritization across Chemical Space

    EPA Science Inventory

    EPA's Exposure Prioritization (Ex Priori) is a simplified, quantitative visual dashboard that makes use of data from various inputs to provide rank-ordered internalized dose metric. This complements other high throughput screening by viewing exposures within all chemical space si...

  2. Liquid plug propagation in flexible microchannels: A small airway model

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Fujioka, H.; Bian, S.; Torisawa, Y.; Huh, D.; Takayama, S.; Grotberg, J. B.

    2009-07-01

    In the present study, we investigate the effect of wall flexibility on the plug propagation and the resulting wall stresses in small airway models with experimental measurements and numerical simulations. Experimentally, a flexible microchannel was fabricated to mimic the flexible small airways using soft lithography. Liquid plugs were generated and propagated through the microchannels. The local wall deformation is observed instantaneously during plug propagation with the maximum increasing with plug speed. The pressure drop across the plug is measured and observed to increase with plug speed, and is slightly smaller in a flexible channel compared to that in a rigid channel. A computational model is then presented to model the steady plug propagation through a flexible channel corresponding to the middle plane in the experimental device. The results show qualitative agreements with experiments on wall shapes and pressure drops and the discrepancies bring up interesting questions on current field of modeling. The flexible wall deforms inward near the plug core region, the deformation and pressure drop across the plug increase with the plug speed. The wall deformation and resulting stresses vary with different longitudinal tensions, i.e., for large wall longitudinal tension, the wall deforms slightly, which causes decreased fluid stress and stress gradients on the flexible wall comparing to that on rigid walls; however, the wall stress gradients are found to be much larger on highly deformable walls with small longitudinal tensions. Therefore, in diseases such as emphysema, with more deformable airways, there is a high possibility of induced injuries on lining cells along the airways because of larger wall stresses and stress gradients.

  3. Bioabsorbable radiopaque water-responsive shape memory embolization plug for temporary vascular occlusion.

    PubMed

    Wong, Yee Shan; Salvekar, Abhijit Vijay; Zhuang, Kun Da; Liu, Hui; Birch, William R; Tay, Kiang Hiong; Huang, Wei Min; Venkatraman, Subbu S

    2016-09-01

    We describe the preparation, characterization and evaluation of a biodegradable radiopaque water-triggered shape memory embolization plug for temporary vascular occlusion. The shape memory occluding device consists of a composite of a radio-opaque filler and a poly (dl-lactide-co-glycolide) (PLGA) blend, which was coated with a crosslinked poly (ethylene glycol) diacrylate (PEGDA) hydrogel. The mechanical properties, the degradation timeframe, the effect of programming conditions on the shape memory behaviour and the extent of radio-opacity for imaging were evaluated. Based on the tests, the mechanism responsible for the water-induced shape memory effect in such an embolization plug was elucidated. Suitable materials were optimized to fabricate an embolic plug prototype and its in vitro performance was evaluated as an occlusion rate (using a custom-built set up) and its biocompatibility. Finally, a feasibility study was conducted in vivo in a rabbit model to investigate the ease of device deployment, device migration and extent of vessel occlusion. The in vivo results demonstrated that the prototypes were visible under fluoroscopy and complete vascular occlusion occurred within 2 min of deployment of the prototypes in vivo. In conclusion, the developed embolization plug enables controlled and temporary vascular embolization, and is ready for safety studies.

  4. Small Scale Mass Flow Plug Calibration

    NASA Technical Reports Server (NTRS)

    Sasson, Jonathan

    2015-01-01

    A simple control volume model has been developed to calculate the discharge coefficient through a mass flow plug (MFP) and validated with a calibration experiment. The maximum error of the model in the operating region of the MFP is 0.54%. The model uses the MFP geometry and operating pressure and temperature to couple continuity, momentum, energy, an equation of state, and wall shear. Effects of boundary layer growth and the reduction in cross-sectional flow area are calculated using an in- integral method. A CFD calibration is shown to be of lower accuracy with a maximum error of 1.35%, and slower by a factor of 100. Effects of total pressure distortion are taken into account in the experiment. Distortion creates a loss in flow rate and can be characterized by two different distortion descriptors.

  5. Arthroscopic meniscal allograft transplantation without bone plugs.

    PubMed

    Alentorn-Geli, Eduard; Seijas Vázquez, Roberto; García Balletbó, Montserrat; Álvarez Díaz, Pedro; Steinbacher, Gilbert; Cuscó Segarra, Xavier; Rius Vilarrubia, Marta; Cugat Bertomeu, Ramón

    2011-02-01

    Partial or total meniscectomy are common procedures performed at Orthopedic Surgery departments. Despite providing a great relief of pain, it has been related to early onset knee osteoarthritis. Meniscal allograft transplantation has been proposed as an alternative to meniscectomy. The purposes of this study were to describe an arthroscopic meniscal allograft transplantation without bone plugs technique and to report the preliminary results. All meniscal allograft transplantations performed between 2001 and 2006 were approached for eligibility, and a total of 35 patients (involving 37 menisci) were finally engaged in the study. Patients were excluded if they had ipsilateral knee ligament reconstruction or cartilage repair surgery before meniscal transplantation or other knee surgeries after the meniscal transplantation. Scores on Lysholm, Subjective IKDC Form, and Visual Analogue Scale (VAS) scale for pain were obtained at a mean follow-up of 38.6 months and compared to pre-operative data. Data on chondral lesions were obtained during the arthroscopic procedure and through imaging (radiographs and MRI) studies pre-operatively. Two graft failures out of 59 transplants (3.4%) were found. Daily life accidents were responsible for all graft failures. Significant improvements for Lysholm, Subjective IKDC Form, and VAS for pain scores following the meniscal allograft transplantation were found (P < 0.0001). Controlling for chondral lesion, there was no significant interactions for Lysholm (n.s.), Subjective IKDC Form (n.s.), and VAS for pain scores (n.s.). This study demonstrated that an arthroscopic meniscal allograft transplantation without bone plugs improved knee function and symptoms after a total meniscectomy. Improvements were observed independently of the degree of chondral lesion.

  6. Strategies for Controlling Plug Loads. A Tool for Reducing Plug Loads in Commercial Buildings

    SciTech Connect

    Torcellini, Paul; Bonnema, Eric; Sheppy, Michael; Pless, Shanti

    2015-09-01

    Plug loads are often not considered as part of the energy savings measures in Commercial Buildings; however, they can account for up to 50% of the energy used in the building. These loads are numerous and often scattered throughout a building. Some of these loads are purchased by the owner and some designed into the building or the tenant finishes for a space. This document provides a strategy and a tool for minimizing these loads.

  7. Carbon Nanostructure-Based Field-Effect Transistors for Label-Free Chemical/Biological Sensors

    PubMed Central

    Hu, PingAn; Zhang, Jia; Li, Le; Wang, Zhenlong; O’Neill, William; Estrela, Pedro

    2010-01-01

    Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased energy consumption and potentially highly miniaturized integration. Owing to their particular structure, excellent electrical properties and high chemical stability, carbon nanotube and graphene based electrical devices have been widely developed for high performance label-free chemical/biological sensors. Here, we review the latest developments of carbon nanostructure-based transistor sensors in ultrasensitive detection of chemical/biological entities, such as poisonous gases, nucleic acids, proteins and cells. PMID:22399927

  8. Mechanistic Understanding of Microbial Plugging for Improved Sweep Efficiency

    SciTech Connect

    Steven Bryant; Larry Britton

    2008-09-30

    Microbial plugging has been proposed as an effective low cost method of permeability reduction. Yet there is a dearth of information on the fundamental processes of microbial growth in porous media, and there are no suitable data to model the process of microbial plugging as it relates to sweep efficiency. To optimize the field implementation, better mechanistic and volumetric understanding of biofilm growth within a porous medium is needed. In particular, the engineering design hinges upon a quantitative relationship between amount of nutrient consumption, amount of growth, and degree of permeability reduction. In this project experiments were conducted to obtain new data to elucidate this relationship. Experiments in heterogeneous (layered) beadpacks showed that microbes could grow preferentially in the high permeability layer. Ultimately this caused flow to be equally divided between high and low permeability layers, precisely the behavior needed for MEOR. Remarkably, classical models of microbial nutrient uptake in batch experiments do not explain the nutrient consumption by the same microbes in flow experiments. We propose a simple extension of classical kinetics to account for the self-limiting consumption of nutrient observed in our experiments, and we outline a modeling approach based on architecture and behavior of biofilms. Such a model would account for the changing trend of nutrient consumption by bacteria with the increasing biomass and the onset of biofilm formation. However no existing model can explain the microbial preference for growth in high permeability regions, nor is there any obvious extension of the model for this observation. An attractive conjecture is that quorum sensing is involved in the heterogeneous bead packs.

  9. Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling

    SciTech Connect

    Randall S. Seright

    2007-09-30

    This final technical progress report describes work performed from October 1, 2004, through May 16, 2007, for the project, 'Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling'. We explored the potential of pore-filling gels for reducing excess water production from both fractured and unfractured production wells. Several gel formulations were identified that met the requirements--i.e., providing water residual resistance factors greater than 2,000 and ultimate oil residual resistance factors (F{sub rro}) of 2 or less. Significant oil throughput was required to achieve low F{sub rro} values, suggesting that gelant penetration into porous rock must be small (a few feet or less) for existing pore-filling gels to provide effective disproportionate permeability reduction. Compared with adsorbed polymers and weak gels, strong pore-filling gels can provide greater reliability and behavior that is insensitive to the initial rock permeability. Guidance is provided on where relative-permeability-modification/disproportionate-permeability-reduction treatments can be successfully applied for use in either oil or gas production wells. When properly designed and executed, these treatments can be successfully applied to a limited range of oilfield excessive-water-production problems. We examined whether gel rheology can explain behavior during extrusion through fractures. The rheology behavior of the gels tested showed a strong parallel to the results obtained from previous gel extrusion experiments. However, for a given aperture (fracture width or plate-plate separation), the pressure gradients measured during the gel extrusion experiments were much higher than anticipated from rheology measurements. Extensive experiments established that wall slip and first normal stress difference were not responsible for the pressure gradient discrepancy. To explain the discrepancy, we noted that the aperture for gel flow (for mobile gel wormholing through concentrated immobile

  10. The Anal Fistula Plug versus the mucosal advancement flap for the treatment of Anorectal Fistula (PLUG trial)

    PubMed Central

    van Koperen, Paul J; Bemelman, Willem A; Bossuyt, Patrick MM; Gerhards, Michael F; Eijsbouts, Quirijn AJ; van Tets, Willem F; Janssen, Lucas WM; Dijkstra, F Robert; van Dalsen, Annette D; Slors, J Frederik M

    2008-01-01

    Background Low transsphincteric fistulas less than 1/3 of the sphincter complex are easy to treat by fistulotomy with a high success rate. High transsphincteric fistulas remain a surgical challenge. Various surgical procedures are available, but recurrence rates of these techniques are disappointingly high. The mucosal flap advancement is considered the gold standard for the treatment of high perianal fistula of cryptoglandular origin by most colorectal surgeons. In the literature a recurrence rate between 0 and 63% is reported for the mucosal flap advancement. Recently Armstrong and colleagues reported on a new biologic anal fistula plug, a bioabsorbable xenograft made of lyophilized porcine intestinal submucosa. Their prospective series of 15 patients with high perianal fistula treated with the anal fistula plug showed promising results. The anal fistula plug trial is designed to compare the anal fistula plug with the mucosal flap advancement in the treatment of high perianal fistula in terms of success rate, continence, postoperative pain, and quality of life. Methods/design The PLUG trial is a randomized controlled multicenter trial. Sixty patients with high perianal fistulas of cryptoglandular origin will be randomized to either the fistula plug or the mucosal advancement flap. Study parameters will be anorectal fistula closure-rate, continence, post-operative pain, and quality of life. Patients will be followed-up at two weeks, four weeks, and 16 weeks. At the final follow-up closure rate is determined by clinical examination by a surgeon blinded for the intervention. Discussion Before broadly implementing the anal fistula plug results of randomized trials using the plug should be awaited. This randomized controlled trial comparing the anal fistula plug and the mucosal advancement flap should provide evidence regarding the effectiveness of the anal fistula plug in the treatment of high perianal fistulas. Trial registration ISRCTN: 97376902 PMID:18573198

  11. In-use measurement of activity, energy use, and emissions of a plug-in hybrid electric vehicle.

    PubMed

    Graver, Brandon M; Frey, H Christopher; Choi, Hyung-Wook

    2011-10-15

    Plug-in hybrid electric vehicles (PHEVs) could reduce transportation air emissions and energy use. However, a method is needed for estimating on-road emissions of PHEVs. To develop a framework for quantifying microscale energy use and emissions (EU&E), measurements were conducted on a Toyota Prius retrofitted with a plug-in battery system on eight routes. Measurements were made using the following: (1) a data logger for the hybrid control system; (2) a portable emissions measurement system; and (3) a global positioning system with barometric altimeter. Trends in EU&E are estimated based on vehicle specific power. Energy economy is quantified based on gasoline consumed by the engine and grid energy consumed by the plug-in battery. Emissions from electricity consumption are estimated based on the power generation mix. Fuel use is approximately 30% lower during plug-in battery use. Grid emissions were higher for CO₂, NO(x), SO₂, and PM compared to tailpipe emissions but lower for CO and hydrocarbons. EU&E depends on engine and plug-in battery operation. The use of two energy sources must be addressed in characterizing fuel economy; overall energy economy is 11% lower if including grid energy use than accounting only for fuel consumption.

  12. Dynamics of Surfactant Liquid Plugs at Bifurcating Lung Airway Models

    NASA Astrophysics Data System (ADS)

    Tavana, Hossein

    2013-11-01

    A surfactant liquid plug forms in the trachea during surfactant replacement therapy (SRT) of premature babies. Under air pressure, the plug propagates downstream and continuously divides into smaller daughter plugs at continuously branching lung airways. Propagating plugs deposit a thin film on airway walls to reduce surface tension and facilitate breathing. The effectiveness of SRT greatly depends on the final distribution of instilled surfactant within airways. To understand this process, we investigate dynamics of splitting of surfactant plugs in engineered bifurcating airway models. A liquid plug is instilled in the parent tube to propagate and split at the bifurcation. A split ratio, R, is defined as the ratio of daughter plug lengths in the top and bottom daughter airway tubes and studied as a function of the 3D orientation of airways and different flow conditions. For a given Capillary number (Ca), orienting airways farther away from a horizontal position reduced R due to the flow of a larger volume into the gravitationally favored daughter airway. At each orientation, R increased with 0.0005 < Ca < 0.05. This effect diminished by decrease in airways diameter. This approach will help elucidate surfactant distribution in airways and develop effective SRT strategies.

  13. Steady propagation of Bingham plugs in 2D channels

    NASA Astrophysics Data System (ADS)

    Zamankhan, Parsa; Takayama, Shuichi; Grotberg, James

    2009-11-01

    The displacement of the yield-stress liquid plugs in channels and tubes occur in many biological systems and industrial processes. Among them is the propagation of mucus plugs in the respiratory tracts as may occur in asthma, cystic fibrosis, or emphysema. In this work the steady propagation of mucus plugs in a 2D channel is studied numerically, assuming that the mucus is a pure Bingham fluid. The governing equations are solved by a mixed-discontinuous finite element formulation and the free surface is resolved with the method of spines. The constitutive equation for a pure Bingham fluid is modeled by a regularization method. Fluid inertia is neglected, so the controlling parameters in a steady displacement are; the capillary number, Ca, Bingham number ,Bn, and the plug length. According to the numerical results, the yield stress behavior of the plug modifies the plug shape, the pattern of the streamlines and the distribution of stresses in the plug domain and along the walls in a significant way. The distribution along the walls is a major factor in studying cell injuries. This work is supported through the grant NIH HL84370.

  14. CHEMICAL SOLUTION DEPOSITION BASED OXIDE BUFFERS AND YBCO COATED CONDUCTORS

    SciTech Connect

    Paranthaman, Mariappan Parans

    2011-01-01

    We have reviewed briefly the growth of buffer and high temperature superconducting oxide thin films using a chemical solution deposition (CSD) method. In the Rolling-Assisted Biaxially Textured Substrates (RABiTS) process, developed at Oak Ridge National Laboratory, utilizes the thermo mechanical processing to obtain the flexible, biaxially oriented copper, nickel or nickel-alloy substrates. Buffers and Rare Earth Barium Copper Oxide (REBCO) superconductors have been deposited epitaxially on the textured nickel alloy substrates. The starting substrate serves as a template for the REBCO layer, which has substantially fewer weak links. Buffer layers play a major role in fabricating the second generation REBCO wire technology. The main purpose of the buffer layers is to provide a smooth, continuous and chemically inert surface for the growth of the REBCO film, while transferring the texture from the substrate to the superconductor layer. To achieve this, the buffer layers need to be epitaxial to the substrate, i.e. they have to nucleate and grow in the same bi-axial texture provided by the textured metal foil. The most commonly used RABiTS multi-layer architectures consist of a starting template of biaxially textured Ni-5 at.% W (Ni-W) substrate with a seed (first) layer of Yttrium Oxide (Y2O3), a barrier (second) layer of Yttria Stabilized Zirconia (YSZ), and a Cerium Oxide (CeO2) cap (third) layer. These three buffer layers are generally deposited using physical vapor deposition (PVD) techniques such as reactive sputtering. On top of the PVD template, REBCO film is then grown by a chemical solution deposition. This article reviews in detail about the list of oxide buffers and superconductor REBCO films grown epitaxially on single crystal and/or biaxially textured Ni-W substrates using a CSD method.

  15. Raman-spectroscopy-based chemical contaminant detection in milk powder

    NASA Astrophysics Data System (ADS)

    Dhakal, Sagar; Chao, Kuanglin; Qin, Jianwei; Kim, Moon S.

    2015-05-01

    Addition of edible and inedible chemical contaminants in food powders for purposes of economic benefit has become a recurring trend. In recent years, severe health issues have been reported due to consumption of food powders contaminated with chemical substances. This study examines the effect of spatial resolution used during spectral collection to select the optimal spatial resolution for detecting melamine in milk powder. Sample depth of 2mm, laser intensity of 200mw, and exposure time of 0.1s were previously determined as optimal experimental parameters for Raman imaging. Spatial resolution of 0.25mm was determined as the optimal resolution for acquiring spectral signal of melamine particles from a milk-melamine mixture sample. Using the optimal resolution of 0.25mm, sample depth of 2mm and laser intensity of 200mw obtained from previous study, spectral signal from 5 different concentration of milk-melamine mixture (1%, 0.5%, 0.1%, 0.05%, and 0.025%) were acquired to study the relationship between number of detected melamine pixels and corresponding sample concentration. The result shows that melamine concentration has a linear relation with detected number of melamine pixels with correlation coefficient of 0.99. It can be concluded that the quantitative analysis of powder mixture is dependent on many factors including physical characteristics of mixture, experimental parameters, and sample depth. The results obtained in this study are promising. We plan to apply the result obtained from this study to develop quantitative detection model for rapid screening of melamine in milk powder. This methodology can also be used for detection of other chemical contaminants in milk powders.

  16. Methodology for Mechanical Property Testing on Fuel Cladding Using an Expanded Plug Wedge Test

    SciTech Connect

    Wang, Jy-An John; Jiang, Hao

    2013-08-01

    compressive stresses were induced by clad bending deformation due to a clad bulging effect (or the barreling effect). The barreling effect caused very large localized shear stress in the clad and left testing material at a high risk of shear failure. The above combined effects will result in highly non-conservative predictions both in strength and ductility of the tested clad, and the associated mechanical properties as well. To overcome/mitigate the mentioned deficiencies associated with the current expansion plug test, systematic studies have been conducted. Through detailed parameter investigation on specific geometry designs, careful filtering of material for the expansion plug, as well as adding newly designed parts to the testing system, a method to reconcile the potential non-conservatism embedded in the expansion plug test system has been discovered. A modified expansion plug testing protocol has been developed based on the method. In order to closely resemble thin-wall theory, a general procedure was also developed to determine the hoop stress in the tested ring specimen. A scaling factor called -factor is defined to correlate the ring load P into hoop stress . , = . The generated stress-strain curve agrees very well with tensile test data in both the elastic and plastic regions.

  17. A MEMS Based Hybrid Preconcentrator/Chemiresistor Chemical Sensor

    SciTech Connect

    HUGHES,ROBERT C.; PATEL,SANJAY V.; MANGINELL,RONALD P.

    2000-06-12

    A hybrid of a microfabricated planar preconcentrator and a four element chemiresistor array chip has been fabricated and the performance as a chemical sensor system has been demonstrated. The close proximity of the chemiresistor sensor to the preconcentrator absorbent layer allows for fast transfer of the preconcentrated molecules during the heating and resorption step. The hybrid can be used in a conventional flow sampling system for detection of low concentrations of analyte molecules or in a pumpless/valveless mode with a grooved lid to confine the desorption plume from the preconcentrator during heating.

  18. CHEMICAL GENETICS: LIGAND-BASED DISCOVERY OF GENE FUNCTION

    PubMed Central

    Stockwell, Brent R.

    2011-01-01

    Chemical genetics is the study of gene-product function in a cellular or organismal context using exogenous ligands. In this approach, small molecules that bind directly to proteins are used to alter protein function, enabling a kinetic analysis of the in vivo consequences of these changes. Recent advances have strongly enhanced the power of exogenous ligands such that they can resemble genetic mutations in terms of their general applicability and target specificity. The growing sophistication of this approach raises the possibility of its application to any biological process. PMID:11253651

  19. Drum plug piercing and sampling device and method

    DOEpatents

    Counts, Kevin T.

    2011-04-26

    An apparatus and method for piercing a drum plug of a drum in order to sample and/or vent gases that may accumulate in a space of the drum is provided. The drum is not damaged and can be reused since the pierced drum plug can be subsequently replaced. The apparatus includes a frame that is configured for engagement with the drum. A cylinder actuated by a fluid is mounted to the frame. A piercer is placed into communication with the cylinder so that actuation of the cylinder causes the piercer to move in a linear direction so that the piercer may puncture the drum plug of the drum.

  20. Description of a novel mating plug mechanism in spiders and the description of the new species Maeota setastrobilaris (Araneae, Salticidae)

    PubMed Central

    Garcilazo-Cruz, Uriel; Alvarez-Padilla, Fernando

    2015-01-01

    Abstract Reproduction in arthropods is an interesting area of research where intrasexual and intersexual mechanisms have evolved structures with several functions. The mating plugs usually produced by males are good examples of these structures where the main function is to obstruct the female genitalia against new sperm depositions. In spiders several types of mating plugs have been documented, the most common ones include solidified secretions, parts of the bulb or in some extraordinary cases the mutilation of the entire palpal bulb. Here, we describe the first case of modified setae, which are located on the cymbial dorsal base, used directly as a mating plug for the Order Araneae in the species Maeota setastrobilaris sp. n. In addition the taxonomic description of Maeota setastrobilaris sp. n. is provided and based on our findings the geographic distribution of this genus is extended to the Northern hemisphere. PMID:26175601

  1. Chemical analysis in space exploration - A lunar-based chemical analysis laboratory (LBCAL)

    NASA Astrophysics Data System (ADS)

    Hobish, Mitchell K.; Gehrke, Charles W.; Ponnamperuma, Cyril; Zumwalt, Robert W.

    Issues that a well-designed LBCAL must address are examined, and an approach whereby appropriate constituencies can provide input to the design and construction processes is outlined. A ready-made cadre to pursue similar projects in support of human space travel is provided. Goals of an LBCAL are to: define the life sciences, planetary, and materials sciences research objectives of a manned lunar base; elucidate the scientific and analytical requirememnts of lunar-based laboratory instrumentation and sample packaging resources to achieve these objectives; review the current state-of-the-art instrumentation for the analytical requirements of the laboratory; and identify needed techniques and technologies for the laboratory, and improvise or fabricate or modify them to suit such a laboratory. Consideration is also given to measurement of astronaut stress, a dedicated clinical analyzer, exobiological research, lunar science, materials science, interdisciplinary science, and terrestrial benefits and spin-offs.

  2. Development and study of chemical vapor deposited tantalum base alloys

    NASA Technical Reports Server (NTRS)

    Meier, G. H.; Bryant, W. A.

    1976-01-01

    A technique for the chemical vapor deposition of alloys was developed. The process, termed pulsing, involves the periodic injection of reactant gases into a previously-evacuated reaction chamber where they blanket the substrate almost instantaneously. Formation of alternating layers of the alloy components and subsequent homogenization allows the formation of an alloy of uniform composition with the composition being determined by the duration and relative numbers of the various cycles. The technique has been utilized to produce dense alloys of uniform thickness and composition (Ta- 10 wt % W) by depositing alternating layers of Ta and W by the hydrogen reduction of TaCl5 and WCl6. A similar attempt to deposit a Ta - 8 wt % W - 2 wt% Hf alloy was unsuccessful because of the difficulty in reducing HfCl4 at temperatures below those at which gas phase nucleation of Ta and W occurred.

  3. Struvite-based fertilizer and its physical and chemical properties.

    PubMed

    Latifian, Maryam; Liu, Jing; Mattiasson, Bo

    2012-12-01

    This study describes a method to formulate struvite fine powder into pellets that are easy to spread on agricultural land. To evaluate the quality of produced pellets, some chemical and physical properties commonly measured for fertilizers were tested. The findings indicated that the salt index and heavy metal content ofstruvite pellets were significantly lower than those of commercial NPK fertilizers. In addition, the percentage of nutrient released from struvite pellets after 105 days was in the range of 9.6-23.2, 8.4-26.7 and 11.3-32.6% for nitrogen, phosphorous and magnesium, respectively, which is considerably lower than that of commercial NPK fertilizer. Among different formulations between struvite crystals and binders, starch and bentonite were the most efficient in agglomerating struvite powder, leading to an increase in the crush strength to over the recommended limit of >2.5 kgf for fertilizer hardness. PMID:23437670

  4. Quantum cascade laser based standoff photoacoustic chemical detection.

    PubMed

    Chen, Xing; Cheng, Liwei; Guo, Dingkai; Kostov, Yordan; Choa, Fow-Sen

    2011-10-10

    Standoff chemical detection with a distance of more than 41 feet using photoacoustic effect and quantum cascade laser (QCL) operated at relatively low power, less than 40 mW, is demonstrated for the first time. The option of using QCL provides the advantages of easy tuning and modulation besides the benefit of compact size, light weight and low power consumption. The standoff detection signal can be calibrated as a function of different parameters such as laser pulse energy, gas vapor concentration and detection distance. The results yield good agreements with theoretical model. Techniques to obtain even longer detection distance and achieve outdoor operations are in the process of implementation and their projection is discussed.

  5. Effectiveness of Instruction Based on the Constructivist Approach on Understanding Chemical Equilibrium Concepts

    ERIC Educational Resources Information Center

    Akkus, Huseyin; Kadayifci, Hakki; Atasoy, Basri; Geban, Omer

    2003-01-01

    The purpose of this study was to identify misconceptions concerning chemical equilibrium concepts and to investigate the effectiveness of instruction based on the constructivist approach over traditional instruction on 10th grade students' understanding of chemical equilibrium concepts. The subjects of this study consisted of 71 10th grade…

  6. Introduction to Chemical Engineering Reactor Analysis: A Web-Based Reactor Design Game

    ERIC Educational Resources Information Center

    Orbey, Nese; Clay, Molly; Russell, T.W. Fraser

    2014-01-01

    An approach to explain chemical engineering through a Web-based interactive game design was developed and used with college freshman and junior/senior high school students. The goal of this approach was to demonstrate how to model a lab-scale experiment, and use the results to design and operate a chemical reactor. The game incorporates both…

  7. Acid-Base Chemistry According to Robert Boyle: Chemical Reactions in Words as well as Symbols

    ERIC Educational Resources Information Center

    Goodney, David E.

    2006-01-01

    Examples of acid-base reactions from Robert Boyle's "The Sceptical Chemist" are used to illustrate the rich information content of chemical equations. Boyle required lengthy passages of florid language to describe the same reaction that can be done quite simply with a chemical equation. Reading or hearing the words, however, enriches the student's…

  8. Work-Based Higher Degrees: Responding to the Knowledge Needs of Chemical Engineers

    ERIC Educational Resources Information Center

    Winberg, Christine

    2007-01-01

    University-workplace partnerships are strategies increasingly called for in higher education. This article reports on collaborative knowledge production between employed professional chemical engineers (registered for higher degrees) and their university-based supervisors (researchers in the field of chemical engineering). The study draws on a…

  9. SYNTHESIS OF PROTEINS BY NATIVE CHEMICAL LIGATION USING FMOC-BASED CHEMISTRY

    SciTech Connect

    Camarero, J A; Mitchell, A R

    2005-01-20

    C-terminal peptide {alpha}-thioesters are valuable intermediates in the synthesis/semisynthesis of proteins by native chemical ligation. They are prepared either by solid-phase peptide synthesis (SPPS) or biosynthetically by protein splicing techniques. The present paper reviews the different methods available for the chemical synthesis of peptide {alpha}-thioesters using Fmoc-based SPPS.

  10. Exploring Secondary Students' Understanding of Chemical Kinetics through Inquiry-Based Learning Activities

    ERIC Educational Resources Information Center

    Chairam, Sanoe; Klahan, Nutsuda; Coll, Richard K.

    2015-01-01

    This research is trying to evaluate the feedback of Thai secondary school students to inquiry-based teaching and learning methods, exemplified by the study of chemical kinetics. This work used the multiple-choice questions, scientifically practical diagram and questionnaire to assess students' understanding of chemical kinetics. The findings…

  11. POTENTIAL INHALATION EXPOSURE TO VOLATILE CHEMICALS IN WATER-BASED HARD-SURFACE CLEANERS

    EPA Science Inventory

    Potential inhalation exposure of building occupants to volatile chemicals in water-based hard-surface cleaners was evaluated by analyzing 267 material safety data sheets (MSDSs). Among the 154 chemicals reported, 44 are volatile or semi-volatile. Hazardous air pollutants (HAPs) r...

  12. Inquiry-Based Examination of Chemical Disruption of Bacterial Biofilms

    ERIC Educational Resources Information Center

    Redelman, Carly V.; Hawkins, Misty A. W.; Drumwright, Franklin R.; Ransdell, Beverly; Marrs, Kathleen; Anderson, Gregory G.

    2012-01-01

    Inquiry-based instruction in the sciences has been demonstrated as a successful educational strategy to use for both high school and college science classrooms. As participants in the NSF Graduate STEM Fellows in K-12 Education (GK-12) Program, we were tasked with creating novel inquiry-based activities for high school classrooms. As a way to…

  13. Endovascular exclusion of complex postsurgical aortic arch pseudoaneurysm using vascular plug devices and a review of vascular plugs.

    PubMed

    Verma, Himanshu; Hiremath, Niranjan; Maiya, Shreesha; George, Robbie K; Tripathi, Ramesh K

    2012-12-01

    We report the management of a patient presenting with haemoptysis due to aortobronchial fistula. He had previously undergone emergency exclusion bypass of a ruptured pseudoaneurysm developing post-aortic coarctation repair. Computed tomography scan showed persistent filling of pseudoaneurysm sac from proximal and distal aortic ligature sites tied during previous exclusion bypass surgery. Successful exclusion of aneurysm was achieved by using 3 vascular plug devices (1 Amplatzer plug II and 2 Amender patent ductus arteriosus occluder devices). We also review types of Amplatzer vascular plugs and their use in peripheral vascular interventions.

  14. Prediction of Drug Indications Based on Chemical Interactions and Chemical Similarities

    PubMed Central

    Huang, Guohua; Lu, Yin; Lu, Changhong; Cai, Yu-Dong

    2015-01-01

    Discovering potential indications of novel or approved drugs is a key step in drug development. Previous computational approaches could be categorized into disease-centric and drug-centric based on the starting point of the issues or small-scaled application and large-scale application according to the diversity of the datasets. Here, a classifier has been constructed to predict the indications of a drug based on the assumption that interactive/associated drugs or drugs with similar structures are more likely to target the same diseases using a large drug indication dataset. To examine the classifier, it was conducted on a dataset with 1,573 drugs retrieved from Comprehensive Medicinal Chemistry database for five times, evaluated by 5-fold cross-validation, yielding five 1st order prediction accuracies that were all approximately 51.48%. Meanwhile, the model yielded an accuracy rate of 50.00% for the 1st order prediction by independent test on a dataset with 32 other drugs in which drug repositioning has been confirmed. Interestingly, some clinically repurposed drug indications that were not included in the datasets are successfully identified by our method. These results suggest that our method may become a useful tool to associate novel molecules with new indications or alternative indications with existing drugs. PMID:25821813

  15. Dry ice plug for hydraulic and pneumatic pipe flushing

    NASA Technical Reports Server (NTRS)

    Francino, L.; Rauch, S.

    1972-01-01

    Development of technique to clear blockages in hydraulic and pneumatic pipes is discussed. Technique consists of using dry ice plug to separate sensitive components from flushing fluid. Diagram of equipment and principles of operation are presented.

  16. The Losing Battle Against Plug-and-Chug

    NASA Astrophysics Data System (ADS)

    Kortemeyer, Gerd

    2016-01-01

    I think most physics teachers would agree that two important components of a proper solution to a numerical physics problem are to first figure out a final symbolic solution and to only plug in numbers in the end. However, in spite of our best efforts, this is not what the majority of students is actually doing. Instead, they tend to plug numbers into formulas without considering the physical meaning of the equations, then frequently take the result and plug it into the next formula—a strategy known as "plug-and-chug." In this chain of calculations, frequently physical insights are lost. If teaching problem solving is proving ineffective, maybe it is possible to steer students onto the right path by posing the problems in different ways?

  17. Frictional Fluid Dynamics and Plug Formation in Multiphase Millifluidic Flow.

    PubMed

    Dumazer, Guillaume; Sandnes, Bjørnar; Ayaz, Monem; Måløy, Knut Jørgen; Flekkøy, Eirik Grude

    2016-07-01

    We study experimentally the flow and patterning of a granular suspension displaced by air inside a narrow tube. The invading air-liquid interface accumulates a plug of granular material that clogs the tube due to friction with the confining walls. The gas percolates through the static plug once the gas pressure exceeds the pore capillary entry pressure of the packed grains, and a moving accumulation front is reestablished at the far side of the plug. The process repeats, such that the advancing interface leaves a trail of plugs in its wake. Further, we show that the system undergoes a fluidization transition-and complete evacuation of the granular suspension-when the liquid withdrawal rate increases beyond a critical value. An analytical model of the stability condition for the granular accumulation predicts the flow regime. PMID:27447527

  18. Porous plug for reducing orifice induced pressure error in airfoils

    NASA Technical Reports Server (NTRS)

    Plentovich, Elizabeth B. (Inventor); Gloss, Blair B. (Inventor); Eves, John W. (Inventor); Stack, John P. (Inventor)

    1988-01-01

    A porous plug is provided for the reduction or elimination of positive error caused by the orifice during static pressure measurements of airfoils. The porous plug is press fitted into the orifice, thereby preventing the error caused either by fluid flow turning into the exposed orifice or by the fluid flow stagnating at the downstream edge of the orifice. In addition, the porous plug is made flush with the outer surface of the airfoil, by filing and polishing, to provide a smooth surface which alleviates the error caused by imperfections in the orifice. The porous plug is preferably made of sintered metal, which allows air to pass through the pores, so that the static pressure measurements can be made by remote transducers.

  19. Astronaut Hoffman replaces fuse plugs on Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Astronaut Jeffrey A. Hoffman sees to the replacement of fuse plugs on the Hubble Space Telescope (HST) during the first of five space walks. Thunderclouds are all that is visible on the dark earth in the background.

  20. Frictional Fluid Dynamics and Plug Formation in Multiphase Millifluidic Flow

    NASA Astrophysics Data System (ADS)

    Dumazer, Guillaume; Sandnes, Bjørnar; Ayaz, Monem; Mâløy, Knut Jørgen; Flekkøy, Eirik Grude

    2016-07-01

    We study experimentally the flow and patterning of a granular suspension displaced by air inside a narrow tube. The invading air-liquid interface accumulates a plug of granular material that clogs the tube due to friction with the confining walls. The gas percolates through the static plug once the gas pressure exceeds the pore capillary entry pressure of the packed grains, and a moving accumulation front is reestablished at the far side of the plug. The process repeats, such that the advancing interface leaves a trail of plugs in its wake. Further, we show that the system undergoes a fluidization transition—and complete evacuation of the granular suspension—when the liquid withdrawal rate increases beyond a critical value. An analytical model of the stability condition for the granular accumulation predicts the flow regime.

  1. Large discharge-volume, silent discharge spark plug

    DOEpatents

    Kang, Michael

    1995-01-01

    A large discharge-volume spark plug for providing self-limiting microdischarges. The apparatus includes a generally spark plug-shaped arrangement of a pair of electrodes, where either of the two coaxial electrodes is substantially shielded by a dielectric barrier from a direct discharge from the other electrode, the unshielded electrode and the dielectric barrier forming an annular volume in which self-terminating microdischarges occur when alternating high voltage is applied to the center electrode. The large area over which the discharges occur, and the large number of possible discharges within the period of an engine cycle, make the present silent discharge plasma spark plug suitable for use as an ignition source for engines. In the situation, where a single discharge is effective in causing ignition of the combustible gases, a conventional single-polarity, single-pulse, spark plug voltage supply may be used.

  2. 30 CFR 250.1715 - How must I permanently plug a well?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Permanent Well Plugging Requirements If you have— Then you must use— (1) Zones in open hole Cement plug(s... zones to isolate fluids in the strata. (2) Open hole below casing (i) A cement plug, set by the displacement method, at least 100 feet above and below deepest casing shoe;(ii) A cement retainer...

  3. 30 CFR 250.1711 - When will MMS order me to permanently plug a well?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false When will MMS order me to permanently plug a... SHELF Decommissioning Activities Permanently Plugging Wells § 250.1711 When will MMS order me to permanently plug a well? MMS will order you to permanently plug a well if that well: (a) Poses a hazard...

  4. Prioritizing chemicals for environmental management in China based on screening of potential risks

    NASA Astrophysics Data System (ADS)

    Yu, Xiangyi; Mao, Yan; Sun, Jinye; Shen, Yingwa

    2014-03-01

    The rapid development of China's chemical industry has created increasing pressure to improve the environmental management of chemicals. To bridge the large gap between the use and safe management of chemicals, we performed a comprehensive review of the international methods used to prioritize chemicals for environmental management. By comparing domestic and foreign methods, we confirmed the presence of this gap and identified potential solutions. Based on our literature review, we developed an appropriate screening method that accounts for the unique characteristics of chemical use within China. The proposed method is based on an evaluation using nine indices of the potential hazard posed by a chemical: three environmental hazard indices (persistence, bioaccumulation, and eco-toxicity), four health hazard indices (acute toxicity, carcinogenicity, mutagenicity, and reproductive and developmental toxicity), and two environmental exposure hazard indices (chemical amount and utilization pattern). The results of our screening agree with results of previous efforts from around the world, confirming the validity of the new system. The classification method will help decisionmakers to prioritize and identify the chemicals with the highest environmental risk, thereby providing a basis for improving chemical management in China.

  5. An integrated hybrid microfluidic device for oviposition-based chemical screening of adult Drosophila melanogaster.

    PubMed

    Leung, Jacob C K; Hilliker, Arthur J; Rezai, Pouya

    2016-02-21

    Chemical screening using Drosophila melanogaster (the fruit fly) is vital in drug discovery, agricultural, and toxicological applications. Oviposition (egg laying) on chemically-doped agar plates is an important read-out metric used to quantitatively assess the biological fitness and behavioral responses of Drosophila. Current oviposition-based chemical screening studies are inaccurate, labor-intensive, time-consuming, and inflexible due to the manual chemical doping of agar. In this paper, we have developed a novel hybrid agar-polydimethylsiloxane (PDMS) microfluidic device for single- and multi-concentration chemical dosing and on-chip oviposition screening of free-flying adult stage Drosophila. To achieve this, we have devised a novel technique to integrate agar with PDMS channels using ice as a sacrificial layer. Subsequently, we have conducted single-chemical toxicity and multiple choice chemical preference assays on adult Drosophila melanogaster using zinc and acetic acid at various concentrations. Our device has enabled us to 1) demonstrate that Drosophila is capable of sensing the concentration of different chemicals on a PDMS-agar microfluidic device, which plays significant roles in determining oviposition site selection and 2) investigate whether oviposition preference differs between single- and multi-concentration chemical environments. This device may be used to study fundamental and applied biological questions in Drosophila and other egg laying insects. It can also be extended in design to develop sophisticated and dynamic chemical dosing and high-throughput screening platforms in the future that are not easily achievable with the existing oviposition screening techniques.

  6. Double-O-Ring Plug For Leak Tests

    NASA Technical Reports Server (NTRS)

    Greene, James H.

    1989-01-01

    Pressure plug features redundant O-ring bore seals and axial port opening laterally into space between O-rings to enable testing of seals. Axial passage in plug connected through radial passage to space between O-rings. Opening used to test O-rings, then sealed with smaller O-ring compressed by machine screw. Useful to seal test or cleanout holes normally kept closed in hydraulic actuators, pumps, and other pressurized systems.

  7. MTR MAIN FLOOR. MEN DEMONSTRATE INSERTION OF DUMMY PLUG INTO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MTR MAIN FLOOR. MEN DEMONSTRATE INSERTION OF DUMMY PLUG INTO AN MTR BEAM HOLE. ONE MAN CHECKS RADIATION LEVEL AT THE END OF THE UNIVERSAL COFFIN, WHILE ANOTHER USES TOOL TO INSERT PLUG INTO HOLE THROUGH COFFIN. MEN WEAR "ANTI-C" (ANTI-CONTAMINATION) CLOTHING. INL NEGATIVE NO. 6198. R.G. Larsen, Photographer, 6/27/1952 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  8. Dual spark plug ignition system for motorcycle internal combustion engine

    SciTech Connect

    Hoeptner, H.W.

    1991-04-02

    This patent describes an ignition system for a motorcycle two cylinder internal combustion engine, the system including magnetically coupled primary and secondary coil means, two spark plugs at each of the cylinders, a source of electrical current, and a single set of contacts controlling electrical current flow to the primary coil means for producing high voltage outputs from the secondary coil means to be delivered to all four of the spark plugs, the secondary coil means including certain secondary coil means operatively connected via the primary coil means with both the of spark plugs at one cylinder, a single cam controlling only the contacts, and a single magnetic core between the primary coil means and both the secondary coil means, and wherein the spark plugs include: two plugs at one cylinder and connected with the certain secondary coil means, two plugs at the second cylinder and connected with the other secondary coil means, the primary coil means including certain primary coil means magnetically coupled to the certain secondary coil means, and other primary coil means magnetically coupled to the other secondary coil means, the certain and other primary coil means being connected in series, electrically, the two spark plugs at one cylinder being electrically connected to opposite ends of the certain secondary coil means, and the two spark plugs at the other cylinder are electrically connected to opposite ends of the other secondary coil means. It comprises the cam driven by the engine for controlling opening of the contacts, the cam rotatable about a first axis, carrier means carrying the contacts, and adjustably rotatable about the axis.

  9. DEVELOPMENT OF SULFATE RADICAL-BASED CHEMICAL OXIDATION PROCESSES FOR GROUNDWATER REMEDIATION

    EPA Science Inventory

    This study investigates the development of novel sulfate radical-based chemical oxidation processes for treatment of groundwater contaminants. Environmentally friendly transition metal (Fe (II), Fe (III)) has been evaluated for the activation of common oxidants (peroxymonosulfat...

  10. Application of chemical mechanical polishing process on titanium based implants.

    PubMed

    Ozdemir, Z; Ozdemir, A; Basim, G B

    2016-11-01

    Modification of the implantable biomaterial surfaces is known to improve the biocompatibility of metallic implants. Particularly, treatments such as etching, sand-blasting or laser treatment are commonly studied to understand the impact of nano/micro roughness on cell attachment. Although, the currently utilized surface modification techniques are known to improve the amount of cell attachment, it is critical to control the level of attachment due to the fact that promotion of bioactivity is needed for prosthetic implants while the cardiac valves, which are also made of titanium, need demotion of cells attachment to be able to function. In this study, a new alternative is proposed to treat the implantable titanium surfaces by chemical mechanical polishing (CMP) technique. It is demonstrated that the application of CMP on the titanium surface helps in modifying the surface roughness of the implant in a controlled manner (inducing nano-scale smoothness or controlled nano/micro roughness). Simultaneously, it is observed that the application of CMP limits the bacteria growth by forming a protective thin surface oxide layer on titanium implants. It is further shown that there is an optimal level of surface roughness where the cell attachment reaches a maximum and the level of roughness is controllable through CMP. PMID:27524033

  11. DESIGN, SYNTHESIS, AND APPLICATION OF THE TRIMETHOPRIM-BASED CHEMICAL TAG FOR LIVE CELL IMAGING

    PubMed Central

    Jing, Chaoran; Cornish, Virginia W.

    2013-01-01

    Over the past decade chemical tags have been developed to complement the use of fluorescent proteins in live cell imaging. Chemical tags retain the specificity of protein labeling achieved with fluorescent proteins through genetic encoding, but provide smaller, more robust tags and modular use of organic fluorophores with high photon-output and tailored functionalities. The trimethoprim-based chemical tag (TMP-tag) was initially developed based on the high affinity interaction between E.coli dihydrofolatereductase and the antibiotic trimethoprim and subsequently rendered covalent and fluorogenic via proximity-induced protein labeling reactions. To date, the TMP-tag is one of the few chemical tags that enable intracellular protein labeling and high-resolution live cell imaging. Here we describe the general design, chemical synthesis, and application of TMP-tag for live cell imaging. Alternative protocols for synthesizing and using the covalent and the fluorogenic TMP-tags are also included. PMID:23839994

  12. Calculations aid breaking of wax-plugged lines

    SciTech Connect

    Gilchrist, R.T. Jr.

    1986-08-01

    Manipulation of pressure/volume data helps locate a wax plug in a pipeline, and it may then be possible to clear the line by interception of the plug with a hot tap. Or, in an extreme case, information obtained from the pressure/volume data will allow better assessment of where to replace the pipe. The possibility of a pipeline becoming plugged by paraffin buildup is greatest in winter when cooler temperatures may cause wax to precipitate and plate out on the pipe walls or completely gel in the line. The risk of plugging is also greatest during pigging. This is because passage of the pig may cause a large mass of wax to accumulate by scraping a thin layer of wax from a long length of pipe. This type of plug does not enlarge once the pipeline is stopped up. It has been successfully cleared by tapping the pipeline at a point within the wax blockage and then pumping the plug out in sections.

  13. Advances and trends in ionophore-based chemical sensors

    NASA Astrophysics Data System (ADS)

    Mikhelson, K. N.; Peshkova, M. A.

    2015-06-01

    The recent advances in the theory and practice of potentiometric, conductometric and optical sensors based on ionophores are critically reviewed. The role of the heterogeneity of the sensor/sample systems is emphasized, and it is shown that due to this heterogeneity such sensors respond to the analyte activities rather than to concentrations. The basics of the origin of the response of all three kinds of ionophore-based sensors are briefly described. The use of novel sensor materials, new preparation and application techniques of the sensors as well as advances in theoretical treatment of the sensor response are analyzed using literature sources published mainly from 2012 to 2014. The basic achievements made in the past are also addressed when necessary for better understanding of the trends in the field of ionophore-based sensors. The bibliography includes 295 references.

  14. Paper-based chemical and biological sensors: Engineering aspects.

    PubMed

    Ahmed, Snober; Bui, Minh-Phuong Ngoc; Abbas, Abdennour

    2016-03-15

    Remarkable efforts have been dedicated to paper-based chemosensors and biosensors over the last few years, mainly driven by the promise of reaching the best trade-off between performance, affordability and simplicity. Because of the low-cost and rapid prototyping of these sensors, recent research has been focused on providing affordable diagnostic devices to the developing world. The recent progress in sensitivity, multi-functionality and integration of microfluidic paper-based analytical devices (µPADs), increasingly suggests that this technology is not only attractive in resource-limited environments but it also represents a serious challenger to silicon, glass and polymer-based biosensors. This review discusses the design, chemistry and engineering aspects of these developments, with a focus on the past few years.

  15. Tuning plasmonic and chemical enhancement for SERS detection on graphene-based Au hybrids.

    PubMed

    Liang, Xiu; Liang, BenLiang; Pan, Zhenghui; Lang, Xiufeng; Zhang, Yuegang; Wang, Guangsheng; Yin, Penggang; Guo, Lin

    2015-12-21

    Various graphene-based Au nanocomposites have been developed as surface-enhanced Raman scattering (SERS) substrates recently. However, efficient use of SERS has been impeded by the difficulty of tuning SERS enhancement effects induced from chemical and plasmonic enhancement by different preparation methods of graphene. Herein, we developed graphene-based Au hybrids through physical sputtering gold NPs on monolayer graphene prepared by chemical vapor deposition (CVD) as a CVD-G/Au hybrid, as well as graphene oxide-gold (GO/Au) and reduced-graphene oxide (rGO/Au) hybrids prepared using the chemical in situ crystallization growth method. Plasmonic and chemical enhancements were tuned effectively by simple methods in these as-prepared graphene-based Au systems. SERS performances of CVD-G/Au, rGO/Au and GO/Au showed a gradually monotonic increasing tendency of enhancement factors (EFs) for adsorbed Rhodamine 6G (R6G) molecules, which show clear dependence on chemical bonds between graphene and Au, indicating that the chemical enhancement can be steadily controlled by chemical groups in a graphene-based Au hybrid system. Most notably, we demonstrate that the optimized GO/Au was able to detect biomolecules of adenine, which displayed high sensitivity with a detection limit of 10(-7) M as well as good reproducibility and uniformity. PMID:26575834

  16. Design of chemical space networks using a Tanimoto similarity variant based upon maximum common substructures.

    PubMed

    Zhang, Bijun; Vogt, Martin; Maggiora, Gerald M; Bajorath, Jürgen

    2015-10-01

    Chemical space networks (CSNs) have recently been introduced as an alternative to other coordinate-free and coordinate-based chemical space representations. In CSNs, nodes represent compounds and edges pairwise similarity relationships. In addition, nodes are annotated with compound property information such as biological activity. CSNs have been applied to view biologically relevant chemical space in comparison to random chemical space samples and found to display well-resolved topologies at low edge density levels. The way in which molecular similarity relationships are assessed is an important determinant of CSN topology. Previous CSN versions were based on numerical similarity functions or the assessment of substructure-based similarity. Herein, we report a new CSN design that is based upon combined numerical and substructure similarity evaluation. This has been facilitated by calculating numerical similarity values on the basis of maximum common substructures (MCSs) of compounds, leading to the introduction of MCS-based CSNs (MCS-CSNs). This CSN design combines advantages of continuous numerical similarity functions with a robust and chemically intuitive substructure-based assessment. Compared to earlier version of CSNs, MCS-CSNs are characterized by a further improved organization of local compound communities as exemplified by the delineation of drug-like subspaces in regions of biologically relevant chemical space.

  17. Tiles made from slag sitall based on chemical industry slag

    SciTech Connect

    Batalin, B.S.; Moskalets, N.B.; Klyuchnik, I.A.; Golius, T.E.

    1987-11-01

    The authors establish the feasibility of obtaining ceramic silicate-based facing tiles from fluoroamphibole slag sitall wastes from the hydropyrolytic production of hydrogen fluoride. The recovered ceramic is tested by x-ray diffraction and electron microscopy for its crystallization behavior, structure, workability, corrosion resistance, phase composition, impact strength, and other properties.

  18. On the Chemical Emergence of Phosphate-Based Biochemistry

    NASA Astrophysics Data System (ADS)

    Kee, Terence

    Contemporary organisms use orthophosphate derivatives (PO43-) in their cell biochemistry,1 yet questions remain as to how Nature was able to accumulate, activate and exploit the or-thophosphate group from geological sources with both poorly solubility and low chemical activ-ity.2 Gulick argued3 a central role for reduced oxidation state phosphorus (P) oxyacids such as H-phosphonates (H2PO3-) and especially H-phosphinates (H2PO2-) in prebiotic chemistry on account of the greater water solubility of their metal salts and, with the presence of P-H bonds, a different reactivity profile to that expected of orthophosphate. The recent demonstration that hydrothermal corrosion of P-rich mineral phases such as schreibersite (Fe,Ni)3P within iron meteorites leads to production of various P-oxyacids including H-phosphonic (H3PO3)4 and H-phosphinic5 acids as well as orthophosphate has reignited interest in reduced oxida-tion state P chemistry in prebiotic environments. We are examining the prebiotic potential of reduced oxidation state P-chemistry through reactions with carbonyl substrates with rea-sonable prebiotic provenance including formaldehyde glycolaldehyde, both intimately involved in the formose reaction for sugar synthesis6 and pyruvic acid,7 a product of glycolysis and feed-stock for the citric acid cycle, a fundamental cellular metablic process whose heritage is considered an ancient one. In this contribution we present some of our latest results on the H-phosphinate-pyruvate system. References: [1] Lodish H et al. (2000) Molecular Cell Biology, 4th Ed., W. H. Freeman Co., New York. [2] Gulick A. (1955) Am. Sci., 43, 479. [3] Gulick A. (1957) Ann. N. Y. Acad. Sci. 69, 309. [4] Pasek M. A. (2008) Proc. Nat. Acad. Sci. USA, 105, 853. [5] Bryant D. E.and Kee T. P. (2006) Chem. Commun. 2344. [6] Weber A. L. (2000) Origins of Life and Evol. Biosph., 30, 33. [7] Cody G. D. et. al. (2000) Science 289, 1337.

  19. Plug-and-play modules for flexible radiosynthesis

    PubMed Central

    Herman, Henry; Flores, Graciela; Quinn, Kevin; Eddings, Mark; Olma, Sebastian; Moore, Melissa D.; Ding, Huijiang; Bobinski, Krzysztof P.; Wang, Mingwei; Williams, Dirk; Wiliams, Darin; Shen, Clifton Kwang-Fu; Phelps, Michael E.; van Dam, R. Michael

    2015-01-01

    We present a plug-and-play radiosynthesis platform and accompanying computer software based on modular subunits that can easily and flexibly be configured to implement a diverse range of radiosynthesis protocols. Modules were developed that perform: (i) reagent storage and delivery, (ii) evaporations and sealed reactions, and (iii) cartridge-based purifications. The reaction module incorporates a simple robotic mechanism that removes tubing from the vessel and replaces it with a stopper prior to sealed reactions, enabling the system to withstand high pressures and thus provide tremendous flexibility in choice of solvents and temperatures. Any number of modules can rapidly be connected together using only a few fluidic connections to implement a particular synthesis, and the resulting system is controlled in a semi-automated fashion by a single software interface. Radiosyntheses of 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG), 1-[18F]fluoro-4-nitrobenzene ([18F]FNB), and 2′-deoxy-2′-[18F]fluoro-1-β-D-arabinofuranosyl cytosine (D-[18F]FAC) were performed to validate the system and demonstrate its versatility. PMID:23702795

  20. Glow plug for an internal combustion engine

    SciTech Connect

    Ito, N.; Atsumi, K.; Mizuno, N.; Kikuchi, T.

    1986-07-08

    A glow plug mounted in a combustion chamber of an internal combustion engine is described which consists of: (1) a heater support member projecting into the combustion chamber of the internal combustion engine, the heater support member being formed of a mixture containing alumina and silicon nitride; (2) a heater member affixed to the surface of the heater support member, the heater member being formed of a mixture containing molybdenum disilicate and silicon nitride, the heater support member and the heater member being integrally sintered; the heater support member being in the form of a rod, and the heater member covering in a U-shaped form the tip end face of the heater support member and the upper and lower face portions of the heater support member contiguous to the end face; (3) first, second and third lead wires for power supply embedded in the heater support member; one end of the first lead wire being connected embeddedly to one end portion of the heater member, one end of the second lead wire being connected embeddedly to the other end portion of the heater member and one end of the third lead wire being connected embeddedly to the central portion of the heater member, thereby forming two heater elements having substantially the same resistance value between the lead wires; (4) a power source; and (5) a power switching means for connecting the power source selectively between the lead wires for power supply according to the state of preheating in the combustion chamber, the power switching means having a switching relay contact for connecting the power source selectively between the third lead wire and the other two lead wires and between the other two lead wires.

  1. Rigid-plug elastic-water model for transient pipe flow with entrapped air pocket

    SciTech Connect

    Zhou, Ling; Liu, Prof. Deyou; Karney, Professor Byran W.; Zhang, Qin Fen; OU, CHANGQI

    2011-01-01

    Pressure transients in a rapidly filling pipe with an entrapped air pocket are investigated analytically. A rigid-plug elastic water model is developed by applying elastic water hammer to the majority of the water column while applying rigid water analysis to a small portion near the air-water interface, which avoids effectively the interpolation error of previous approaches. Moreover, another two simplified models are introduced respectively based on constant water length and by neglecting water elasticity. Verification of the three models is confirmed by experimental results. Calculations show that the simplification of constant water length is feasible for small air pockets. The complete rigid water model is appropriate for cases with large initial air volume. The rigid-plug elastic model can predict all the essential features for the entire range of initial air fraction considered in this study, and it is the effective model for analysis of pressure transients of entrapped air.

  2. Space R/T base: Propulsion (high thrust chemical)

    NASA Technical Reports Server (NTRS)

    Gorland, S.

    1991-01-01

    The topics presented are covered in viewgraph form. The programmatic objective is to provide a technology base and maintain an institutional capability for continued advances in the development of advanced space propulsion systems to support launch, upper stage, orbit transfer and ascent/descent engines. The technical objectives are to study: (1) validated design and analytical codes for cryogenic turbopump bearings and seals; (2) design methodologies and diagnostic capabilities for combustion stability; and (3) reduced operations cost, increase life, safety, higher energy density propellants, and in-situ engine concepts.

  3. Slug-plug flow analyses of stratified flows in a horizontal duct by means of MARS

    SciTech Connect

    Kunugi, T.; Ose, Y.; Banat, M.

    1999-07-01

    The objectives of this study are to perform the slug-plug flow analyses of stratified flows in a horizontal duct by means of the MARS (Multi-interfaces Advection and Reconstruction Solver) developed by the author which based on the piece-wise linear calculation as a volume tracking procedure and the continuum surface force model (CSF) for the surface tension, and to investigate the effect of the Bernoulli term for slug-plug flows, i.e., so-called the topological law, on the competition between inertial forces and gravitation forces. Some discussion on the primary jump condition at the interface in the MARS is described in the paper. The results of the direct numerical simulation (DNS) by the MARS are compared with the experimental one. The slugging positions obtained by the DNS are in good agreement with the experimental one. Since the mass conservation between before the plugging and after slugging can be shown by the DNS here, the authors may conclude that this physical/numerical model based on the MARS is reliable.

  4. Digital Rock Physics: Mechanical Properties of Carbonate Core Plug at Different Resolutions

    NASA Astrophysics Data System (ADS)

    Jouini, M. S.; Faisal, T. F.; Islam, A.; Chevalier, S.; Jouiad, M.; Sassi, M.

    2014-12-01

    Digital Rock Physics (DRP) is a novel technology that could be used to generate accurate, fast and cost effective special core analysis (SCAL) properties to support reservoir characterization and simulation tools. For this work, Micro-CT images at different resolutions have been used to run simulations to determine elastic properties like bulk, shear, Young's Modulus and Poisson's ratio of a dry carbonate core plug from Abu Dhabi reservoirs. Pre processing and segmentation of raw images is performed in FEI 3D visualization and analysis tool Avizo. Carbonates are characterized by a very complex pore-space structure and so a high degree of heterogeneity. Abaqus that is based on Finite Element Method is used to run 2D and 3D elastic simulations. Results will be compared by simulating the same core-plug in an alternative segmentation and FEM modeling environment used previously by Jouini & Vega et al. 2012 [1]. Acoustic wave propagation experiments at different confining pressures are performed in the laboratory Triaxial machine to determine the dynamic Young's modulus and Poisson's ratio for the same core plug. Expeirmental results are compared with numerical results. [1] Jouini, M.S. and Vega, S. 2012. Simulation of carbonate rocks elastic properties using 3D X-Ray computed tomography images based on Discrete Element Method and Finite Element Method. 46th US Rock Mechanics / Geomechanics Symposium, Chicago, Il, USA, 24-27 June 2012.

  5. Inquiry-based examination of chemical disruption of bacterial biofilms.

    PubMed

    Redelman, Carly V; Hawkins, Misty A W; Drumwright, Franklin R; Ransdell, Beverly; Marrs, Kathleen; Anderson, Gregory G

    2012-01-01

    Inquiry-based instruction in the sciences has been demonstrated as a successful educational strategy to use for both high school and college science classrooms. As participants in the NSF Graduate STEM Fellows in K-12 Education (GK-12) Program, we were tasked with creating novel inquiry-based activities for high school classrooms. As a way to introduce microbiology, molecular biology, ecology, and human health to students, we created a laboratory activity involving formation of biofilms composed of environmental bacteria from pond water and investigation into the resistance of these biofilms to antimicrobial agents. Two high schools participated in this study in different ways. Pike High School biology and advanced environmental science classrooms obtained pond water samples and grew biofilms from the bacteria in the pond water on plastic plates. They also observed killing of these biofilms by common household antimicrobial agents. As a senior capstone project, students at Arsenal Technical High School built on these research findings by isolating two different bacterial strains from the pond water and demonstrating the stimulatory effect of ethanol on biofilms formed by isolated bacterial strains. These activities were successful at introducing complex biological topics to high school students in a unique and exciting way. The students scored significantly higher on postactivity surveys compared with preactivity surveys that measured microbiology knowledge and experimental design knowledge. Furthermore, these projects seemed to elicit an excitement for science in the students who participated.

  6. Neural network based analysis for chemical sensor arrays

    SciTech Connect

    Hashem, S.; Keller, P.E.; Kouzes, R.T.; Kangas, L.J.

    1995-04-01

    Compact, portable systems capable of quickly identifying contaminants in the field are of great importance when monitoring the environment. In this paper, we examine the effectiveness of using artificial neural networks for real-time data analysis of a sensor array. Analyzing the sensor data in parallel may allow for rapid identification of contaminants in the field without requiring highly selective individual sensors. We use a prototype sensor array which consists of nine tin-oxide Taguchi-type sensors, a temperature sensor, and a humidity sensor. We illustrate that by using neural network based analysis of the sensor data, the selectivity of the sensor array may be significantly improved, especially when some (or all) the sensors are not highly selective.

  7. Climate-based archetypes for the environmental fate assessment of chemicals.

    PubMed

    Ciuffo, Biagio; Sala, Serenella

    2013-11-15

    Emissions of chemicals have been on the rise for years, and their impacts are greatly influenced by spatial differentiation. Chemicals are usually emitted locally but their impact can be felt both locally and globally, due to their chemical properties and persistence. The variability of environmental parameters in the emission compartment may affect the chemicals' fate and the exposure at different orders of magnitude. The assessment of the environmental fate of chemicals and the inherent spatial differentiation requires the use of multimedia models at various levels of complexity (from a simple box model to complex computational and high-spatial-resolution models). The objective of these models is to support ecological and human health risk assessment, by reducing the uncertainty of chemical impact assessments. The parameterisation of spatially resolved multimedia models is usually based on scenarios of evaluative environments, or on geographical resolutions related to administrative boundaries (e.g. countries/continents) or landscape areas (e.g. watersheds, eco-regions). The choice of the most appropriate scale and scenario is important from a management perspective, as a balance should be reached between a simplified approach and computationally intensive multimedia models. In this paper, which aims to go beyond the more traditional approach based on scale/resolution (cell, country, and basin), we propose and assess climate-based archetypes for the impact assessment of chemicals released in air. We define the archetypes based on the main drivers of spatial variability, which we systematically identify by adopting global sensitivity analysis techniques. A case study that uses the high resolution multimedia model MAPPE (Multimedia Assessment of Pollutant Pathways in the Environment) is presented. Results of the analysis showed that suitable archetypes should be both climate- and chemical-specific, as different chemicals (or groups of them) have different traits

  8. Climate-based archetypes for the environmental fate assessment of chemicals.

    PubMed

    Ciuffo, Biagio; Sala, Serenella

    2013-11-15

    Emissions of chemicals have been on the rise for years, and their impacts are greatly influenced by spatial differentiation. Chemicals are usually emitted locally but their impact can be felt both locally and globally, due to their chemical properties and persistence. The variability of environmental parameters in the emission compartment may affect the chemicals' fate and the exposure at different orders of magnitude. The assessment of the environmental fate of chemicals and the inherent spatial differentiation requires the use of multimedia models at various levels of complexity (from a simple box model to complex computational and high-spatial-resolution models). The objective of these models is to support ecological and human health risk assessment, by reducing the uncertainty of chemical impact assessments. The parameterisation of spatially resolved multimedia models is usually based on scenarios of evaluative environments, or on geographical resolutions related to administrative boundaries (e.g. countries/continents) or landscape areas (e.g. watersheds, eco-regions). The choice of the most appropriate scale and scenario is important from a management perspective, as a balance should be reached between a simplified approach and computationally intensive multimedia models. In this paper, which aims to go beyond the more traditional approach based on scale/resolution (cell, country, and basin), we propose and assess climate-based archetypes for the impact assessment of chemicals released in air. We define the archetypes based on the main drivers of spatial variability, which we systematically identify by adopting global sensitivity analysis techniques. A case study that uses the high resolution multimedia model MAPPE (Multimedia Assessment of Pollutant Pathways in the Environment) is presented. Results of the analysis showed that suitable archetypes should be both climate- and chemical-specific, as different chemicals (or groups of them) have different traits

  9. PPLN laser-based system for chemical imaging

    NASA Astrophysics Data System (ADS)

    Ludowise, Peter D.; Ottesen, David K.; Kulp, Thomas J.; Goers, Uta-Barbara; Celina, M.; Armstrong, K.; Allendorf, Sarah W.

    1999-10-01

    An infrared-imaging instrument is being developed to provide in situ qualitative and quantitative assessment of hydrocarbon contaminants on metallic surfaces for cleaning verification. A continuous-wave infrared optical parametric oscillator (OPO), based on the quasi-phasematched material periodically poled lithium niobate (PPLN), is interfaced with an InSb focal plane array camera to perform fast, non-invasive analysis by reflectance spectroscopy. The period range of the designed fan-out PPLN crystal determines the range of the output wavelength of the light source. It is able to scan hundreds of wavenumbers positioned in the range of 2820 - 3250 cm-1, which is sufficient to detect functional groups of common organic compounds (-CH, -OH, and -NH). The capability of the instrument has been demonstrated in a preliminary investigation of reflectance measurements for hydrocarbon solvents (methanol and d-limonene) on an aluminum surface. A substantial difference in absorption is obtained for the two solvents at two different laser-illumination wavelengths, thus permitting hydrocarbon detection and molecular species differentiation. Preliminary reflectance spectra of a mixture of aliphatic hydrocarbon lubricants and drawing agents on an aluminum panel are also presented. The relative thickness of the hydrocarbon thin film is determined by the intensity ratio of images acquired at two different laser illumination frequencies.

  10. Grouping 34 Chemicals Based on Mode of Action Using Connectivity Mapping.

    PubMed

    De Abrew, K Nadira; Kainkaryam, Raghunandan M; Shan, Yuqing K; Overmann, Gary J; Settivari, Raja S; Wang, Xiaohong; Xu, Jun; Adams, Rachel L; Tiesman, Jay P; Carney, Edward W; Naciff, Jorge M; Daston, George P

    2016-06-01

    Connectivity mapping is a method used in the pharmaceutical industry to find connections between small molecules, disease states, and genes. The concept can be applied to a predictive toxicology paradigm to find connections between chemicals, adverse events, and genes. In order to assess the applicability of the technique for predictive toxicology purposes, we performed gene array experiments on 34 different chemicals: bisphenol A, genistein, ethinyl-estradiol, tamoxifen, clofibrate, dehydorepiandrosterone, troglitazone, diethylhexyl phthalate, flutamide, trenbolone, phenobarbital, retinoic acid, thyroxine, 1α,25-dihydroxyvitamin D3, clobetasol, farnesol, chenodeoxycholic acid, progesterone, RU486, ketoconazole, valproic acid, desferrioxamine, amoxicillin, 6-aminonicotinamide, metformin, phenformin, methotrexate, vinblastine, ANIT (1-naphthyl isothiocyanate), griseofulvin, nicotine, imidacloprid, vorinostat, 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) at the 6-, 24-, and 48-hour time points for 3 different concentrations in the 4 cell lines: MCF7, Ishikawa, HepaRG, and HepG2 GEO (super series accession no.: GSE69851). The 34 chemicals were grouped in to predefined mode of action (MOA)-based chemical classes based on current literature. Connectivity mapping was used to find linkages between each chemical and between chemical classes. Cell line-specific linkages were compared with each other and to test whether the method was platform and user independent, a similar analysis was performed against publicly available data. The study showed that the method can group chemicals based on MOAs and the inter-chemical class comparison alluded to connections between MOAs that were not predefined. Comparison to the publicly available data showed that the method is user and platform independent. The results provide an example of an alternate data analysis process for high-content data, beneficial for predictive toxicology, especially when grouping chemicals for read across

  11. The water intensity of the plugged-in automotive economy.

    PubMed

    King, Carey W; Webber, Michael E

    2008-06-15

    Converting light-duty vehicles from full gasoline power to electric power, by using either hybrid electric vehicles or fully electric power vehicles, is likely to increase demand for water resources. In the United States in 2005, drivers of 234 million cars, lighttrucks, and SUVs drove approximately 2.7 trillion miles and consumed over 380 million gallons of gasoline per day. We compare figures from literature and government surveys to calculate the water usage, consumption, and withdrawal, in the United States during petroleum refining and electricity generation. In displacing gasoline miles with electric miles, approximately 2-3 [corrected] times more water is consumed (0.24 [corrected] versus 0.07--0.14 gallons/mile) and over 12 [corrected] times more water is withdrawn (7.8 [corrected] versus 0.6 gallons/mile) primarily due to increased water cooling of thermoelectric power plants to accommodate increased electricity generation. Overall, we conclude that the impact on water resources from a widespread shift to grid-based transportation would be substantial enough to warrant consideration for relevant public policy decision-making. That is not to say that the negative impacts on water resources make such a shift undesirable, but rather this increase in water usage presents a significant potential impact on regional water resources and should be considered when planning for a plugged-in automotive economy.

  12. Engineering estimates of impurity fluxes on the ITER port plugs

    NASA Astrophysics Data System (ADS)

    Kotov, Vladislav

    2016-10-01

    Predictions of impurity fluxes are required for design analysis of the ITER optical diagnostics. In the present paper a simplified model is proposed for calculation of the neutral impurity fluxes on the recessed surfaces which are not in direct contact with plasma. The method is based on the Monte-Carlo simulation of the neutral particles transport in prescribed and fixed plasma background. The plasma parameters are projected from experimental observations, scalings and ITER modelling results. Blobs are approximated as stationary hot species. Results of 2D simulations with toroidally uniform wall and of the ‘2.5D model’ are presented. In this latter the 3D geometry of ports is implemented, but details of the incident ion flux distribution on the first wall panels are neglected. The calculated worst case gross deposition rate of Be in the middle of the port plug faces reaches almost 0.1 nm s-1. At the same time, the obtained Be erosion to deposition ratio at those locations is always larger than 5, indicating high probability of net erosion conditions there.

  13. The water intensity of the plugged-in automotive economy.

    PubMed

    King, Carey W; Webber, Michael E

    2008-06-15

    Converting light-duty vehicles from full gasoline power to electric power, by using either hybrid electric vehicles or fully electric power vehicles, is likely to increase demand for water resources. In the United States in 2005, drivers of 234 million cars, lighttrucks, and SUVs drove approximately 2.7 trillion miles and consumed over 380 million gallons of gasoline per day. We compare figures from literature and government surveys to calculate the water usage, consumption, and withdrawal, in the United States during petroleum refining and electricity generation. In displacing gasoline miles with electric miles, approximately 2-3 [corrected] times more water is consumed (0.24 [corrected] versus 0.07--0.14 gallons/mile) and over 12 [corrected] times more water is withdrawn (7.8 [corrected] versus 0.6 gallons/mile) primarily due to increased water cooling of thermoelectric power plants to accommodate increased electricity generation. Overall, we conclude that the impact on water resources from a widespread shift to grid-based transportation would be substantial enough to warrant consideration for relevant public policy decision-making. That is not to say that the negative impacts on water resources make such a shift undesirable, but rather this increase in water usage presents a significant potential impact on regional water resources and should be considered when planning for a plugged-in automotive economy. PMID:18605548

  14. Chemical name extraction based on automatic training data generation and rich feature set.

    PubMed

    Yan, Su; Spangler, W Scott; Chen, Ying

    2013-01-01

    The automation of extracting chemical names from text has significant value to biomedical and life science research. A major barrier in this task is the difficulty of getting a sizable and good quality data to train a reliable entity extraction model. Another difficulty is the selection of informative features of chemical names, since comprehensive domain knowledge on chemistry nomenclature is required. Leveraging random text generation techniques, we explore the idea of automatically creating training sets for the task of chemical name extraction. Assuming the availability of an incomplete list of chemical names, called a dictionary, we are able to generate well-controlled, random, yet realistic chemical-like training documents. We statistically analyze the construction of chemical names based on the incomplete dictionary, and propose a series of new features, without relying on any domain knowledge. Compared to state-of-the-art models learned from manually labeled data and domain knowledge, our solution shows better or comparable results in annotating real-world data with less human effort. Moreover, we report an interesting observation about the language for chemical names. That is, both the structural and semantic components of chemical names follow a Zipfian distribution, which resembles many natural languages.

  15. Reagent based DOS: a "Click, Click, Cyclize" strategy to probe chemical space.

    PubMed

    Rolfe, Alan; Lushington, Gerald H; Hanson, Paul R

    2010-05-01

    The synthesis of small organic molecules as probes for discovering new therapeutic agents has been an important aspect of chemical-biology. Herein we report a reagent-based, diversity-oriented synthetic (DOS) strategy to probe chemical and biological space via a "Click, Click, Cyclize" protocol. In this DOS approach, three sulfonamide linchpins underwent cyclization protocols with a variety of reagents to yield a collection of structurally diverse S-heterocycles. In silico analysis is utilized to evaluate the diversity of the compound collection against chemical space (PC analysis), shape space (PMI) and polar surface area (PSA) calculations.

  16. Clustering and rule-based classifications of chemical structures evaluated in the biological activity space.

    PubMed

    Schuffenhauer, Ansgar; Brown, Nathan; Ertl, Peter; Jenkins, Jeremy L; Selzer, Paul; Hamon, Jacques

    2007-01-01

    Classification methods for data sets of molecules according to their chemical structure were evaluated for their biological relevance, including rule-based, scaffold-oriented classification methods and clustering based on molecular descriptors. Three data sets resulting from uniformly determined in vitro biological profiling experiments were classified according to their chemical structures, and the results were compared in a Pareto analysis with the number of classes and their average spread in the profile space as two concurrent objectives which were to be minimized. It has been found that no classification method is overall superior to all other studied methods, but there is a general trend that rule-based, scaffold-oriented methods are the better choice if classes with homogeneous biological activity are required, but a large number of clusters can be tolerated. On the other hand, clustering based on chemical fingerprints is superior if fewer and larger classes are required, and some loss of homogeneity in biological activity can be accepted.

  17. Chemicals identified in human biological media: a data base. Third annual report, October 1981

    SciTech Connect

    Cone, M.V.; Baldauf, M.F.; Martin, F.M.

    1981-12-01

    Data from almost 1600 of the 3800 body-burden documents collected to date have been entered in the data base as of October 1981. The emphasis on including recent literature and significant research documents has resulted in a chronological mix of articles from 1974 to the present. When body-burden articles are identified, data are extracted and entered in the data base by chemical and tissue/body fluid. Each data entry comprises a single record (or line entry) and is assigned a record number. If a particular document deals with more than one chemical and/or tissue, there will be multiple records for that document. For example, a study of 5 chemicals in each of 3 tissues has 15 different records (or 15 line entries) in the data base with 15 record numbers. Record numbers are assigned consecutively throughout the entire data base and appear in the upper left corner of the first column for each record.

  18. Physical and Chemical Investigations of Selected Buckminsterfullerene-Based Materials

    NASA Astrophysics Data System (ADS)

    Dykes, John West

    Studies of materials based on the molecule C _{60} have been performed in three complementary areas; namely, the reaction and passivation of aluminum with C_{60}, nanometer-scale materials engineering utilizing C _{60}, and the critical magnetic fields of superconducting rm K_3C _{60}. The majority of the C _{60} powder used in the investigations was produced in-house. Steps of the process for generating C_{60} from graphitic carbon are given. Fullerene-containing soot was generated in a modified plasma-arc reactor. Fullerenes were separated from soot using Soxhlet extraction. Lastly, C _{60} was separated from the other fullerenes using liquid chromatography. Experiments on the reaction of C_ {60} with aluminum were done on aluminum foils in ultra-high vacuum using Auger spectroscopy, temperature -programmed desorption, photoluminescence, and soft x-ray photoelectron spectroscopy. Strong bonding between C _{60} and aluminum is reported. Results show that when multilayer C_{60} is evaporated onto clean aluminum, all molecules except the monolayer in contact with the aluminum desorb when the sample is heated to 578 K. Photoelectron spectroscopy measurements indicate that electrons transfer from C _{60} to the aluminum at the interface. Additionally, the data may reveal that C_{60} molecules diffuse intact into the aluminum bulk when heating to the aluminum surface melting temperature occurs. The ease of preparing monolayer C_ {60} coverage on a surface by multilayer C_{60} evaporation followed by sublimation of all molecules but those in direct surface contact was examined for the preparation of multilayer and binding structures. The viability of the technique was not definitive. However, Fe/C_{60 }/Fe trilayers may show antiferromagnetic coupling and hence giant magnetoresistance at room temperature. Further, the use of C_{60} to bond metals to semiconductors is related. To resolve superconducting properties, an examination of rm K_3C_{60} was initiated. Most of

  19. A synthetic biochemistry module for production of bio-based chemicals from glucose.

    PubMed

    Opgenorth, Paul H; Korman, Tyler P; Bowie, James U

    2016-06-01

    Synthetic biochemistry, the cell-free production of biologically based chemicals, is a potentially high-yield, flexible alternative to in vivo metabolic engineering. To limit costs, cell-free systems must be designed to operate continuously with minimal addition of feedstock chemicals. We describe a robust, efficient synthetic glucose breakdown pathway and implement it for the production of bioplastic. The system's performance suggests that synthetic biochemistry has the potential to become a viable industrial alternative.

  20. Incorporating biologically based models into assessments of risk from chemical contaminants

    NASA Technical Reports Server (NTRS)

    Bull, R. J.; Conolly, R. B.; De Marini, D. M.; MacPhail, R. C.; Ohanian, E. V.; Swenberg, J. A.

    1993-01-01

    The general approach to assessment of risk from chemical contaminants in drinking water involves three steps: hazard identification, exposure assessment, and dose-response assessment. Traditionally, the risks to humans associated with different levels of a chemical have been derived from the toxic responses observed in animals. It is becoming increasingly clear, however, that further information is needed if risks to humans are to be assessed accurately. Biologically based models help clarify the dose-response relationship and reduce uncertainty.

  1. Design and analysis of a silicon-based antiresonant reflecting optical waveguide chemical sensor

    NASA Astrophysics Data System (ADS)

    Remley, Kate A.; Weisshaar, Andreas

    1996-08-01

    The design of a silicon-based antiresonant reflecting optical waveguide (ARROW) chemical sensor is presented, and its theoretical performance is compared with that of a conventional structure. The use of an ARROW structure permits incorporation of a thick guiding region for efficient coupling to a single-mode fiber. A high-index overlay is added to fine tune the sensitivity of the ARROW chemical sensor. The sensitivity of the sensor is presented, and design trade-offs are discussed.

  2. [Qualitative analysis of chemical constituents in Si-Wu Decoction based on TCM component database].

    PubMed

    Wang, Zhen-fang; Zhao, Yang; Fan, Zi-quan; Kang, Li-ping; Qiao, Li-rui; Zhang, Jie; Gao, Yue; Ma, Bai-ping

    2015-10-01

    In order to clarify the chemical constituents of Si-Wu Decoction rapidly and holistically, we analyzed the ethanol extract of Si-Wu Decoction by UPLC/Q-TOF-MSE and UNIFI which based on traditional Chinese medicine database, the probable structures of 113 compounds were identified. The results show that this method can rapidly and effectively characterize the chemical compounds of Si-Wu Decoction and provide a new solution for identification of components from complex TCM extract.

  3. A synthetic biochemistry module for production of bio-based chemicals from glucose.

    PubMed

    Opgenorth, Paul H; Korman, Tyler P; Bowie, James U

    2016-06-01

    Synthetic biochemistry, the cell-free production of biologically based chemicals, is a potentially high-yield, flexible alternative to in vivo metabolic engineering. To limit costs, cell-free systems must be designed to operate continuously with minimal addition of feedstock chemicals. We describe a robust, efficient synthetic glucose breakdown pathway and implement it for the production of bioplastic. The system's performance suggests that synthetic biochemistry has the potential to become a viable industrial alternative. PMID:27065234

  4. Quantum Chemical Simulations Reveal Acetylene-Based Growth Mechanisms in the Chemical Vapor Deposition Synthesis of Carbon Nanotubes

    SciTech Connect

    Eres, Gyula; Wang, Ying; Gao, Xingfa; Qian, Hu-Jun; Ohta, Yasuhito; Wu, Xiaona; Morokuma, Keiji; Irle, Stephan

    2014-01-01

    Nonequilibrium quantum chemical molecular dynamics (QM/MD) simulation of early stages in the nucleation process of carbon nanotubes from acetylene feedstock on an Fe38 cluster was performed based on the density-functional tight-binding (DFTB) potential. Representative chemical reactions were studied by complimentary static DFTB and density functional theory (DFT) calculations. Oligomerization and cross-linking reactions between carbon chains were found as the main reaction pathways similar to that suggested in previous experimental work. The calculations highlight the inhibiting effect of hydrogen for the condensation of carbon ring networks, and a propensity for hydrogen disproportionation, thus enriching the hydrogen content in already hydrogen-rich species and abstracting hydrogen content in already hydrogen-deficient clusters. The ethynyl radical C2H was found as a reactive, yet continually regenerated species, facilitating hydrogen transfer reactions across the hydrocarbon clusters. The nonequilibrium QM/MD simulations show the prevalence of a pentagon-first nucleation mechanism where hydrogen may take the role of one arm of an sp2 carbon Y-junction. The results challenge the importance of the metal carbide formation for SWCNT cap nucleation in the VLS model and suggest possible alternative routes following hydrogen-abstraction acetylene addition (HACA)-like mechanisms commonly discussed in combustion synthesis.

  5. Experimental investigation of gas hydrate formation, plugging and transportability in partially dispersed and water continuous systems

    NASA Astrophysics Data System (ADS)

    Vijayamohan, Prithvi

    in water. These experiments indicate that the partially dispersed systems tend to be problematic and are more severe cases with respect to flow assurance when compared to systems where the water is completely dispersed in oil. We have found that the partially dispersed systems are distinct, and are not an intermediate case between water dominated, and water-in-oil emulsified systems. Instead the experiments indicate that the hydrate formation and plugging mechanism for these systems are very complex. Hydrate growth is very rapid for such systems when compared to 100% water cut systems. The plugging mechanism for these systems is a combination of various phenomena (wall growth, agglomeration, bedding/settling, etc). Three different oils with different viscosities have been used to investigate the transportability of hydrates with respect to oil properties. The experiments indicate that the transportability of hydrates increases with increase in oil viscosity. The data from the tests performed provide the basis for a mechanistic model for hydrate formation and plugging in partially dispersed systems. It is found that in systems that were in stratified flow regime before hydrate onset, the hydrates eventually settled on the pipe walls thereby decreasing the flow area for the flow of fluids. In systems that were in the slug flow regime before hydrate formation, moving beds of hydrates were the main cause for plugging. In both the flow regimes, the systems studied entered a plugging regime beyond a certain hydrate concentration. This is termed as φplugging onset and can be used as an indicator to calculate the amount of hydrates that can be transported safely without requiring any additional treatment for a given set of flow characteristics. A correlation to calculate this hydrate concentration based on easily accessible parameters is developed in terms of flow characteristics and oil properties. The work performed in this thesis has enhanced the understanding of the

  6. Early experience on peripheral vascular application of the vascular plugs

    PubMed Central

    Rohit, Manoj Kumar; Sinha, Alok Kumar; Kamana, Naveen Krishna

    2013-01-01

    Background Transcatheter closure of various congenital and acquired vascular malformations with Amplatzer Vascular plugs I and II has been established. Here we present our experience with device closure. Materials and methods Between October 2006 and August 2012, nine (three males and six females) patients aged between 11 months and 62 years (mean age 19 years) underwent percutaneous device closure with AVP I and II vascular plugs for congenital and acquired arteriovenous malformation and cardiac diverticulum are presented here. Results One case of coronary cameral fistula, four cases of pulmonary arteriovenous fistula, one case of large major aortopulmonary collaterals (in tetralogy of Fallot closed before intracardiac repair), one case of congenital cardiac diverticulum, one case of fistula between external carotid artery and internal jugular vein and one case of iatrogenic carotid jugular fistula were successfully closed with AVP I and II plugs. Overall in nine cases, 16 AVP I and II plugs were deployed to occlude feeding vessels and one cardiac diverticulum. The technical success rate was 100%. No major complications were observed. Conclusion Amplatzer vascular plugs can be used successfully for closure of various congenital and acquired vascular malformations with good result. PMID:24206877

  7. RCC Plug Repair Thermal Tools for Shuttle Mission Support

    NASA Technical Reports Server (NTRS)

    Rodriguez, Alvaro C.; Anderson, Brian P.

    2010-01-01

    A thermal math model for the Space Shuttle Reinforced Carbon-Carbon (RCC) Plug Repair was developed to increase the confidence in the repair entry performance and provide a real-time mission support tool. The thermal response of the plug cover plate, local RCC, and metallic attach hardware can be assessed with this model for any location on the wing leading edge. The geometry and spatial location of the thermal mesh also matches the structural mesh which allows for the direct mapping of temperature loads and computation of the thermoelastic stresses. The thermal model was correlated to a full scale plug repair radiant test. To utilize the thermal model for flight analyses, accurate predictions of protuberance heating were required. Wind tunnel testing was performed at CUBRC to characterize the heat flux in both the radial and angular directions. Due to the complexity of the implementation of the protuberance heating, an intermediate program was developed to output the heating per nodal location for all OML surfaces in SINDA format. Three Design Reference Cases (DRC) were evaluated with the correlated plug thermal math model to bound the environments which the plug repair would potentially be used.

  8. Slugs and Plugs: the Role of Conduit Boundary Conditions in Shaping Strombolian Explosive Activity

    NASA Astrophysics Data System (ADS)

    Llewellin, E. W.; Del Bello, E.; Mathias, S.; Lane, S. J.; James, M. R.; Taddeucci, J.; Capponi, A.; Scarlato, P.

    2015-12-01

    Strombolian activity is characterized by quasi-periodic, short-lived explosions, which vary greatly in magnitude. The explosions are understood to be driven by the bursting of large, overpressured 'slugs' of magmatic gas, which have ascended the conduit. We use scaled laboratory analogue experiments and numerical modelling to investigate the impact of varying the boundary conditions at the top and bottom of the volcanic conduit, and find that they strongly influence the character and explosivity of strombolian explosions. The presence of a viscous plug at the top of the conduit has been inferred from recent studies of strombolian pyroclasts, which indicate that degassed, crystal-rich magma, and gas-rich, crystal-poor magma co-exist and mingle in the shallow part of the volcanic conduit. We investigate the impact of the plug on eruptive behaviour experimentally, and find that the presence of a viscous plug enhances explosivity by increasing the overpressure within the ascending gas slug. We also find that the plug is prone to fluid-dynamic instability as the gas slug passes through it, causing the low and high viscosity magma analogues to intermingle, explaining the origin of the mingled pyroclasts observed in nature. The instabilities can also cause the slug to break into smaller pockets of gas, providing an explanation for pulsations in strombolian explosions, recently revealed by high-speed videography. Separate analogue experiments, and numerical modelling, are used to investigate slug ascent under contrasting lower boundary conditions: zero-flux; and constant-pressure. Analogue conduit experiments typically use a zero-flux lower boundary (i.e. the base of the pipe is sealed). We show that a more-realistic constant-pressure boundary condition dramatically changes slug ascent velocity and the development of overpressure. Together these two studies constitute a new framework for understanding the role of the boundary conditions in shaping strombolian explosive

  9. Computational Noise Study of a Supersonic Short Conical Plug-Nozzle Jet

    NASA Technical Reports Server (NTRS)

    Das, Indu S.; Khavaran, Abbas; Das, A. P.

    1996-01-01

    A computational jet noise study of a short conical plug-nozzle (CPN) is presented. The CPN has an exit diameter of 45 mm and the geometrical configuration closely approximates that of an ideal contoured plug-nozzle having shockless flow at pressure ratio xi(sub d) = 3.62. The gasdynamics of the jet flows have been predicted using the CFD code, NPARC with k-epsilon turbulence model; these data are then used for noise computations based on the modified GE/MGB code. The study covers a range of pressure ratio, 2.0 less than or equal to xi less than or equal to 5.0. The agreement of the computational results with the available experimental data is favorable. The results indicate consistent noise reduction effectiveness of the CPN as compared to equivalent convergent, convergent-divergent and ideal contoured plug nozzles at all pressure ratios. At design pressure ratio, codes predict noise levels within 4.0 dB of the measurements; and at off-design pressure ratios, in general, within 5.0 dB except at very high frequencies when deviations up to 10 dB are noted. The shock formation mechanism in the CPN jet is noted to be basically different from those in the convergent and CD nozzle jets.

  10. Field Trial of a Low-Cost, Distributed Plug Load Monitoring System

    SciTech Connect

    Auchter, B.; Cautley, D.; Ahl, D.; Earle, L.; Jin, X.

    2014-03-01

    Researchers have struggled to inventory and characterize the energy use profiles of the ever-growing category of so-called miscellaneous electric loads (MELs) because plug-load monitoring is cost-prohibitive to the researcher and intrusive to the homeowner. However, these data represent a crucial missing link to understanding how homes use energy. Detailed energy use profiles would enable the nascent automated home energy management (AHEM) industry to develop effective control algorithms that target consumer electronics and other plug loads. If utility and other efficiency programs are to incent AHEM devices, they need large-scale datasets that provide statistically meaningful justification of their investments by quantifying the aggregate energy savings achievable. To address this need, NREL researchers investigated a variety of plug-load measuring devices available commercially and tested them in the laboratory to identify the most promising candidates for field applications. This report centers around the lessons learned from a field validation of one proof-of-concept system, called Smartenit (formerly SimpleHomeNet). The system was evaluated based on the rate of successful data queries, reliability over a period of days to weeks, and accuracy. This system offers good overall performance when deployed with up to 10 end nodes in a residential environment, although deployment with more nodes and in a commercial environment is much less robust. NREL concludes that the current system is useful in selected field research projects, with the recommendation that system behavior is observed over time.

  11. Modeling and characteristic of the SMT Board Plug connector in high speed optical communication system

    NASA Astrophysics Data System (ADS)

    Wu, Haoran; Dong, Zhenzhen; Wang, Tanglin; Zhao, Heng; Feng, Junbo; Cui, Naidi; Teng, Jie; Guo, Jin

    2015-04-01

    Modeling and characteristic of the SMT Board Plug connector, which is used to connect micro optical transceiver to the main board, are proposed and analyzed in this paper. When the high speed signal transfers from the PCB of transceiver to main board through SMT Board Plug connector, the structure and material discontinuity of the connector causes insertion losses and impedance mismatches. This makes the performance of high speed digital system exacerbated. So it is essential to analyze the signal transfer characteristics of the connector and find out what factors affected the signal quality at the design stage of the digital system. To solve this problem, Ansoft's High Frequency Structure Simulator (HFSS), based on the finite element method, was employed to build accurate 3D models, analyze the effects of various structure parameters, and obtain the full-wave characteristics of the SMT Board Plug connectors in this paper. Then an equivalent circuit model was developed. The circuit parameters were extracted precisely in the frequency range of interests by using the curve fitting method in ADS software, and the result was in good agreement with HFSS simulations up to 8GHz with different structure parameters. At last, the measurement results of S-parameter and eye diagram were given and the S-parameters showed good coincidence between the measurement and HFSS simulation up to 4GHz.

  12. Material removal mechanism of copper chemical mechanical polishing in a periodate-based slurry

    NASA Astrophysics Data System (ADS)

    Cheng, Jie; Wang, Tongqing; He, Yongyong; Lu, Xinchun

    2015-05-01

    The material removal mechanism of copper in a periodate-based slurry during barrier layer chemical mechanical polishing (CMP) has not been intensively investigated. This paper presents a study of the copper surface film chemistry and mechanics in a periodate-based slurry. On this basis, the controlling factor of the copper CMP material removal mechanism is proposed. The results show that the chemical and electrochemical reaction products on the copper surface are complex and vary considerably as a function of the solution pH. Under acidic conditions (pH 4) the copper surface underwent strong chemical dissolution while the corrosion was mild and uniform under alkaline conditions (pH 11). The corrosion effect was the lowest in near neutral solutions because the surface was covered with non-uniform Cu(IO3)2·H2O/Cu-periodate/copper oxides films, which had better passivation effect. The surface film thickness and mechanical removal properties were studied by AES and AFM nano-scratch tests. Based on the combined surface film analysis and CMP experiment results, it can be concluded that the controlling factor during copper CMP in a periodate-based slurry is the chemical-enhanced mechanical removal of the surface films. The periodate-based slurry should be modified by the addition of corrosion inhibitors and complexing agents to achieve a good copper surface quality with moderate chemical dissolution.

  13. [Research progress in salting-out extraction of bio-based chemicals].

    PubMed

    Dai, Jianying; Liu, Chunjiao; Sun, Yaqin; Xiu, Zhilong

    2013-10-01

    Bio-refinery using cheap biomass focuses mainly on strain improvement and fermentation strategies whereas less effort is made on down-stream processing. Using cheap biomass more impurities are introduced into the fermentation broths than mono-sugar substrate, thus down-stream processing for bio-based chemicals becomes the key problem in industrial production. The technique called salting-out extraction (SOE) was introduced in this review, which is used to separate target products from fermentation broth on the basis of partition difference of chemicals in two phases formed by mixing salts and organic solvents (or amphipathic chemicals) with broth at suitable ratios. The effect of solvents and salts on the formation of two aqueous phases, especially short chain alcohols and inorganic salts, and the application of SOE in recovery of bio-based chemicals, such as lactic acid, 1,3-propanediol, 2,3-butanediol and acetoin were summarized. The bio-chemicals were efficiently recovered from fermentation broth, and most of the impurities (cells and proteins) were removed in the same step. This technique is promising in the separation of bio-based chemicals, especially the recovery of hydrophilic molecules with low molecular weights.

  14. [Research progress in salting-out extraction of bio-based chemicals].

    PubMed

    Dai, Jianying; Liu, Chunjiao; Sun, Yaqin; Xiu, Zhilong

    2013-10-01

    Bio-refinery using cheap biomass focuses mainly on strain improvement and fermentation strategies whereas less effort is made on down-stream processing. Using cheap biomass more impurities are introduced into the fermentation broths than mono-sugar substrate, thus down-stream processing for bio-based chemicals becomes the key problem in industrial production. The technique called salting-out extraction (SOE) was introduced in this review, which is used to separate target products from fermentation broth on the basis of partition difference of chemicals in two phases formed by mixing salts and organic solvents (or amphipathic chemicals) with broth at suitable ratios. The effect of solvents and salts on the formation of two aqueous phases, especially short chain alcohols and inorganic salts, and the application of SOE in recovery of bio-based chemicals, such as lactic acid, 1,3-propanediol, 2,3-butanediol and acetoin were summarized. The bio-chemicals were efficiently recovered from fermentation broth, and most of the impurities (cells and proteins) were removed in the same step. This technique is promising in the separation of bio-based chemicals, especially the recovery of hydrophilic molecules with low molecular weights. PMID:24432659

  15. 3D Chemical Similarity Networks for Structure-Based Target Prediction and Scaffold Hopping.

    PubMed

    Lo, Yu-Chen; Senese, Silvia; Damoiseaux, Robert; Torres, Jorge Z

    2016-08-19

    Target identification remains a major challenge for modern drug discovery programs aimed at understanding the molecular mechanisms of drugs. Computational target prediction approaches like 2D chemical similarity searches have been widely used but are limited to structures sharing high chemical similarity. Here, we present a new computational approach called chemical similarity network analysis pull-down 3D (CSNAP3D) that combines 3D chemical similarity metrics and network algorithms for structure-based drug target profiling, ligand deorphanization, and automated identification of scaffold hopping compounds. In conjunction with 2D chemical similarity fingerprints, CSNAP3D achieved a >95% success rate in correctly predicting the drug targets of 206 known drugs. Significant improvement in target prediction was observed for HIV reverse transcriptase (HIVRT) compounds, which consist of diverse scaffold hopping compounds targeting the nucleotidyltransferase binding site. CSNAP3D was further applied to a set of antimitotic compounds identified in a cell-based chemical screen and identified novel small molecules that share a pharmacophore with Taxol and display a Taxol-like mechanism of action, which were validated experimentally using in vitro microtubule polymerization assays and cell-based assays.

  16. Nano-based chemical sensor array systems for uninhabited ground and airborne vehicles

    NASA Astrophysics Data System (ADS)

    Brantley, Christina; Ruffin, Paul B.; Edwards, Eugene

    2009-03-01

    In a time when homemade explosive devices are being used against soldiers and in the homeland security environment, it is becoming increasingly evident that there is an urgent need for high-tech chemical sensor packages to be mounted aboard ground and air vehicles to aid soldiers in determining the location of explosive devices and the origin of bio-chemical warfare agents associated with terrorist activities from a safe distance. Current technologies utilize relatively large handheld detection systems that are housed on sizeable robotic vehicles. Research and development efforts are underway at the Army Aviation & Missile Research, Development, and Engineering Center (AMRDEC) to develop novel and less expensive nano-based chemical sensors for detecting explosives and chemical agents used against the soldier. More specifically, an array of chemical sensors integrated with an electronics control module on a flexible substrate that can conform to and be surface-mounted to manned or unmanned vehicles to detect harmful species from bio-chemical warfare and other explosive devices is being developed. The sensor system under development is a voltammetry-based sensor system capable of aiding in the detection of any chemical agent and in the optimization of sensor microarray geometry to provide nonlinear Fourier algorithms to characterize target area background (e.g., footprint areas). The status of the research project is reviewed in this paper. Critical technical challenges associated with achieving system cost, size, and performance requirements are discussed. The results obtained from field tests using an unmanned remote controlled vehicle that houses a CO2/chemical sensor, which detects harmful chemical agents and wirelessly transmits warning signals back to the warfighter, are presented. Finally, the technical barriers associated with employing the sensor array system aboard small air vehicles will be discussed.

  17. Eddy Current Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

    NASA Technical Reports Server (NTRS)

    England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

    2015-01-01

    An eddy-current-minimizing flow plug has open flow channels formed between the plug's inlet and outlet. Each open flow channel includes (i) a first portion that originates at the inlet face and converges to a location within the plug that is downstream of the inlet, and (ii) a second portion that originates within the plug and diverges to the outlet. The diverging second portion is approximately twice the length of the converging first portion. The plug is devoid of planar surface regions at its inlet and outlet, and in fluid flow planes of the plug that are perpendicular to the given direction of a fluid flowing therethrough.

  18. Studies on powder plug formation using a simulated capsule filling machine.

    PubMed

    Britten, J R; Barnett, M I; Armstrong, N A

    1996-03-01

    Using an apparatus which simulates the action of a Macofar 13-2 dosating-type capsule-filling machine, the variation in plug weight and density with changing machine parameters has been studied. The piston ejection speed has no effect on plug properties. However increase in compression speed leads to a less consolidated powder plug and hence reduced plug weight. Application of higher pressures reduces plug weight changes, but would be expected to affect release characteristics. Comparison of axial and radial pressures generated by plugs of Starch 1500 and lubricated lactose show significant differences which can be explained by the different consolidation and elastic properties of the two solids. PMID:8737048

  19. Plug nozzles: The ultimate customer driven propulsion system

    NASA Technical Reports Server (NTRS)

    Aukerman, Carl A.

    1991-01-01

    This paper presents the results of a study applying the plug cluster nozzle concept to the propulsion system for a typical lunar excursion vehicle. Primary attention for the design criteria is given to user defined factors such as reliability, low volume, and ease of propulsion system development. Total thrust and specific impulse are held constant in the study while other parameters are explored to minimize the design chamber pressure. A brief history of the plug nozzle concept is included to point out the advanced level of technology of the concept and the feasibility of exploiting the variables considered in this study. The plug cluster concept looks very promising as a candidate for consideration for the ultimate customer driven propulsion system.

  20. Flexible Plug Repair for Shuttle Wing Leading Edge

    NASA Technical Reports Server (NTRS)

    Camarda, Charles J.; Sikora, Joseph; Smith, Russel; Rivers, H.; Scotti, Stephen J.; Fuller, Alan M.; Klacka, Robert; Reinders, Martin; Schwind, Francis; Sullivan, Brian; Lester, Dean

    2012-01-01

    In response to the Columbia Accident Investigation Board report, a plug repair kit has been developed to enable astronauts to repair the space shuttle's wing leading edge (WLE) during orbit. The plug repair kit consists of several 17.78- cm-diameter carbon/silicon carbide (C/SiC) cover plates of various curvatures that can be attached to the refractory carbon-carbon WLE panels using a TZM refractory metal attach mechanism. The attach mechanism is inserted through the damage in the WLE panel and, as it is tightened, the cover plate flexes to conform to the curvature of the WLE panel within 0.050 mm. An astronaut installs the repair during an extravehicular activity (EVA). After installing the plug repair, edge gaps are checked and the perimeter of the repair is sealed using a proprietary material, developed to fill cracks and small holes in the WLE.

  1. Tuning plasmonic and chemical enhancement for SERS detection on graphene-based Au hybrids

    NASA Astrophysics Data System (ADS)

    Liang, Xiu; Liang, Benliang; Pan, Zhenghui; Lang, Xiufeng; Zhang, Yuegang; Wang, Guangsheng; Yin, Penggang; Guo, Lin

    2015-11-01

    Various graphene-based Au nanocomposites have been developed as surface-enhanced Raman scattering (SERS) substrates recently. However, efficient use of SERS has been impeded by the difficulty of tuning SERS enhancement effects induced from chemical and plasmonic enhancement by different preparation methods of graphene. Herein, we developed graphene-based Au hybrids through physical sputtering gold NPs on monolayer graphene prepared by chemical vapor deposition (CVD) as a CVD-G/Au hybrid, as well as graphene oxide-gold (GO/Au) and reduced-graphene oxide (rGO/Au) hybrids prepared using the chemical in situ crystallization growth method. Plasmonic and chemical enhancements were tuned effectively by simple methods in these as-prepared graphene-based Au systems. SERS performances of CVD-G/Au, rGO/Au and GO/Au showed a gradually monotonic increasing tendency of enhancement factors (EFs) for adsorbed Rhodamine 6G (R6G) molecules, which show clear dependence on chemical bonds between graphene and Au, indicating that the chemical enhancement can be steadily controlled by chemical groups in a graphene-based Au hybrid system. Most notably, we demonstrate that the optimized GO/Au was able to detect biomolecules of adenine, which displayed high sensitivity with a detection limit of 10-7 M as well as good reproducibility and uniformity.Various graphene-based Au nanocomposites have been developed as surface-enhanced Raman scattering (SERS) substrates recently. However, efficient use of SERS has been impeded by the difficulty of tuning SERS enhancement effects induced from chemical and plasmonic enhancement by different preparation methods of graphene. Herein, we developed graphene-based Au hybrids through physical sputtering gold NPs on monolayer graphene prepared by chemical vapor deposition (CVD) as a CVD-G/Au hybrid, as well as graphene oxide-gold (GO/Au) and reduced-graphene oxide (rGO/Au) hybrids prepared using the chemical in situ crystallization growth method. Plasmonic

  2. Quantum calculation of protein NMR chemical shifts based on the automated fragmentation method.

    PubMed

    Zhu, Tong; Zhang, John Z H; He, Xiao

    2015-01-01

    The performance of quantum mechanical methods on the calculation of protein NMR chemical shifts is reviewed based on the recently developed automatic fragmentation quantum mechanics/molecular mechanics (AF-QM/MM) approach. By using the Poisson-Boltzmann (PB) model and first solvation water molecules, the influence of solvent effect is also discussed. Benefiting from the fragmentation algorithm, the AF-QM/MM approach is computationally efficient, linear-scaling with a low pre-factor, and thus can be applied to routinely calculate the ab initio NMR chemical shifts for proteins of any size. The results calculated using Density Functional Theory (DFT) show that when the solvent effect is included, this method can accurately reproduce the experimental ¹H NMR chemical shifts, while the ¹³C NMR chemical shifts are less affected by the solvent. However, although the inclusion of solvent effect shows significant improvement for ¹⁵N chemical shifts, the calculated values still have large deviations from the experimental observations. Our study further demonstrates that AF-QM/MM calculated results accurately reflect the dependence of ¹³C(α) NMR chemical shifts on the secondary structure of proteins, and the calculated ¹H chemical shift can be utilized to discriminate the native structure of proteins from decoys.

  3. Versatile Friction Stir Welding/Friction Plug Welding System

    NASA Technical Reports Server (NTRS)

    Carter, Robert

    2006-01-01

    A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

  4. In silico screening of estrogen-like chemicals based on different nonlinear classification models.

    PubMed

    Liu, Huanxiang; Papa, Ester; Walker, John D; Gramatica, Paola

    2007-07-01

    Increasing concern is being shown by the scientific community, government regulators, and the public about endocrine-disrupting chemicals that are adversely affecting human and wildlife health through a variety of mechanisms. There is a great need for an effective means of rapidly assessing endocrine-disrupting activity, especially estrogen-simulating activity, because of the large number of such chemicals in the environment. In this study, quantitative structure activity relationship (QSAR) models were developed to quickly and effectively identify possible estrogen-like chemicals based on 232 structurally-diverse chemicals (training set) by using several nonlinear classification methodologies (least-square support vector machine (LS-SVM), counter-propagation artificial neural network (CP-ANN), and k nearest neighbour (kNN)) based on molecular structural descriptors. The models were externally validated by 87 chemicals (prediction set) not included in the training set. All three methods can give satisfactory prediction results both for training and prediction sets, and the most accurate model was obtained by the LS-SVM approach through the comparison of performance. In addition, our model was also applied to about 58,000 discrete organic chemicals; about 76% were predicted not to bind to Estrogen Receptor. The obtained results indicate that the proposed QSAR models are robust, widely applicable and could provide a feasible and practical tool for the rapid screening of potential estrogens.

  5. Relationship between first-order decay coefficients in ponds, for plug flow, CSTR and dispersed flow regimes.

    PubMed

    von, Sperling M

    2002-01-01

    Adequate consideration of the hydraulic regime of a pond is essential in the analysis of BOD and coliform removal, and considerable divergence exists in the literature when reporting removal coefficients. This paper aims at integrating the existing approaches, by quantifying the relationship between the first-order removal coefficients K from the three main hydraulic regimes (CSTR, plug flow and dispersed flow) adopted in the design and performance evaluation of ponds. Based on theoretical considerations and statistical regression analyses, the relationship between the K values is investigated, quantified and modelled. Two tables are presented and two equations are proposed, which allow conversion of K values obtained for dispersed flow to (a) K for CSTR and (b) K for plug flow, based on the hydraulic detention time t and the dispersion number d. These coefficients, when applied in the CSTR or plug-flow equations, will give approximately the same prediction of the effluent concentration as that obtained when using the dispersed-flow model with its proper coefficient. With this approach designers can apply, and researchers can report, K values for the two idealised flow patterns (CSTR and plug flow).

  6. 2-Keto acids based biosynthesis pathways for renewable fuels and chemicals.

    PubMed

    Tashiro, Yohei; Rodriguez, Gabriel M; Atsumi, Shota

    2015-03-01

    Global energy and environmental concerns have driven the development of biological chemical production from renewable sources. Biological processes using microorganisms are efficient and have been traditionally utilized to convert biomass (i.e., glucose) to useful chemicals such as amino acids. To produce desired fuels and chemicals with high yield and rate, metabolic pathways have been enhanced and expanded with metabolic engineering and synthetic biology approaches. 2-Keto acids, which are key intermediates in amino acid biosynthesis, can be converted to a wide range of chemicals. 2-Keto acid pathways were engineered in previous research efforts and these studies demonstrated that 2-keto acid pathways have high potential for novel metabolic routes with high productivity. In this review, we discuss recently developed 2-keto acid-based pathways.

  7. Structure-mechanism-based engineering of chemical regulators targeting distinct pathological factors in Alzheimer's disease

    NASA Astrophysics Data System (ADS)

    Beck, Michael W.; Derrick, Jeffrey S.; Kerr, Richard A.; Oh, Shin Bi; Cho, Woo Jong; Lee, Shin Jung C.; Ji, Yonghwan; Han, Jiyeon; Tehrani, Zahra Aliakbar; Suh, Nayoung; Kim, Sujeong; Larsen, Scott D.; Kim, Kwang S.; Lee, Joo-Yong; Ruotolo, Brandon T.; Lim, Mi Hee

    2016-10-01

    The absence of effective therapeutics against Alzheimer's disease (AD) is a result of the limited understanding of its multifaceted aetiology. Because of the lack of chemical tools to identify pathological factors, investigations into AD pathogenesis have also been insubstantial. Here we report chemical regulators that demonstrate distinct specificity towards targets linked to AD pathology, including metals, amyloid-β (Aβ), metal-Aβ, reactive oxygen species, and free organic radicals. We obtained these chemical regulators through a rational structure-mechanism-based design strategy. We performed structural variations of small molecules for fine-tuning their electronic properties, such as ionization potentials and mechanistic pathways for reactivity towards different targets. We established in vitro and/or in vivo efficacies of the regulators for modulating their targets' reactivities, ameliorating toxicity, reducing amyloid pathology, and improving cognitive deficits. Our chemical tools show promise for deciphering AD pathogenesis and discovering effective drugs.

  8. Structure-mechanism-based engineering of chemical regulators targeting distinct pathological factors in Alzheimer's disease

    PubMed Central

    Beck, Michael W.; Derrick, Jeffrey S.; Kerr, Richard A.; Oh, Shin Bi; Cho, Woo Jong; Lee, Shin Jung C.; Ji, Yonghwan; Han, Jiyeon; Tehrani, Zahra Aliakbar; Suh, Nayoung; Kim, Sujeong; Larsen, Scott D.; Kim, Kwang S.; Lee, Joo-Yong; Ruotolo, Brandon T.; Lim, Mi Hee

    2016-01-01

    The absence of effective therapeutics against Alzheimer's disease (AD) is a result of the limited understanding of its multifaceted aetiology. Because of the lack of chemical tools to identify pathological factors, investigations into AD pathogenesis have also been insubstantial. Here we report chemical regulators that demonstrate distinct specificity towards targets linked to AD pathology, including metals, amyloid-β (Aβ), metal–Aβ, reactive oxygen species, and free organic radicals. We obtained these chemical regulators through a rational structure-mechanism-based design strategy. We performed structural variations of small molecules for fine-tuning their electronic properties, such as ionization potentials and mechanistic pathways for reactivity towards different targets. We established in vitro and/or in vivo efficacies of the regulators for modulating their targets' reactivities, ameliorating toxicity, reducing amyloid pathology, and improving cognitive deficits. Our chemical tools show promise for deciphering AD pathogenesis and discovering effective drugs. PMID:27734843

  9. Identification and quantitative analysis of chemical compounds based on multiscale linear fitting of terahertz spectra

    NASA Astrophysics Data System (ADS)

    Qiao, Lingbo; Wang, Yingxin; Zhao, Ziran; Chen, Zhiqiang

    2014-07-01

    Terahertz (THz) time-domain spectroscopy is considered as an attractive tool for the analysis of chemical composition. The traditional methods for identification and quantitative analysis of chemical compounds by THz spectroscopy are all based on full-spectrum data. However, intrinsic features of the THz spectrum only lie in absorption peaks due to existence of disturbances, such as unexpected components, scattering effects, and barrier materials. We propose a strategy that utilizes Lorentzian parameters of THz absorption peaks, extracted by a multiscale linear fitting method, for both identification of pure chemicals and quantitative analysis of mixtures. The multiscale linear fitting method can automatically remove background content and accurately determine Lorentzian parameters of the absorption peaks. The high recognition rate for 16 pure chemical compounds and the accurate predicted concentrations for theophylline-lactose mixtures demonstrate the practicability of our approach.

  10. Process for selectively plugging subterranean formations with a melamine resin

    SciTech Connect

    Falk, D.O.

    1984-09-25

    Highly permeable zones in a subterranean formation are selectively plugged by injecting a melamine formaldehyde solution via a well into the highly permeable zones. The solution is water soluble and preferentially enters water-containing zones where it reacts to form a resin at a temperature of from about 25/sup 0/ C. to about 120/sup 0/ C. and a pH of from about 7 to 12 and over a period of from about 1 to 4 days. The resulting resin substantially plugs the highly permeable zones in the formation.

  11. Selectively plugging subterranean formations with a hydrocarbon soluble fluid

    SciTech Connect

    Falk, D. O.

    1984-11-13

    Highly permeable zones in a subterranean formation vertically bounded by a relatively less permeable zone are selectively plugged by injecting an emulsion of melamine and formaldehyde in an alcohol medium via a well into the highly permeable zones. The emulsion is hydrocarbon soluble are preferentially envelops the highly permeable zones where it reacts to form a resin at a temperature of from about 80/sup 0/ C. to about 250/sup 0/ C. and a pH of from about 7 to 12 and over a period of from about 1 to 4 days. The resulting resin substantially plugs the highly permeable zones in the formation.

  12. Method for preventing plugging in the pyrolysis of agglomerative coals

    DOEpatents

    Green, Norman W.

    1979-01-23

    To prevent plugging in a pyrolysis operation where an agglomerative coal in a nondeleteriously reactive carrier gas is injected as a turbulent jet from an opening into an elongate pyrolysis reactor, the coal is comminuted to a size where the particles under operating conditions will detackify prior to contact with internal reactor surfaces while a secondary flow of fluid is introduced along the peripheral inner surface of the reactor to prevent backflow of the coal particles. The pyrolysis operation is depicted by two equations which enable preselection of conditions which insure prevention of reactor plugging.

  13. Coagulation sensors based on magnetostrictive delay lines for biomedical and chemical engineering applications

    NASA Astrophysics Data System (ADS)

    Maliaritsi, E.; Zoumpoulakis, L.; Simitzis, J.; Vassiliou, P.; Hristoforou, E.

    2006-04-01

    Coagulation sensors based on the magnetostrictive delay line technique are presented in this paper. They are based on magnetostrictive ribbons and are used for measuring the coagulation, curing or solidification time of different liquids. Experimental results indicate that the presented sensing elements can determine the blood coagulation with remarkable repeatability, thus allowing their use as blood coagulation sensors. Additionally, results indicate that they can also measure curing time of resins, solidification of fluids and coagulation of chemical substances, therefore allowing their implementation in chemical engineering applications.

  14. Monocrystalline molybdenum silicide based quantum dot superlattices grown by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Savelli, Guillaume; Silveira Stein, Sergio; Bernard-Granger, Guillaume; Faucherand, Pascal; Montès, Laurent

    2016-09-01

    This paper presents the growth of doped monocrystalline molybdenum-silicide-based quantum dot superlattices (QDSL). This is the first time that such nanostructured materials integrating molybdenum silicide nanodots have been grown. QDSL are grown by reduced pressure chemical vapor deposition (RPCVD). We present here their crystallographic structures and chemical properties, as well as the influence of the nanostructuration on their thermal and electrical properties. Particularly, it will be shown some specific characteristics for these QDSL, such as a localization of nanodots between the layers, unlike other silicide based QDSL, an accumulation of doping atoms near the nanodots, and a strong decrease of the thermal conductivity obtained thanks to the nanostructuration.

  15. Development of endocannabinoid-based chemical probes for the study of cannabinoid receptors.

    PubMed

    Martín-Couce, Lidia; Martín-Fontecha, Mar; Capolicchio, Samanta; López-Rodríguez, María L; Ortega-Gutiérrez, Silvia

    2011-07-28

    We report the synthesis of new chemical probes (1a,b, 2a-c, 3a-c) based on the structure of the main endocannabinoids for their use in biological systems directly or via click chemistry. As proof of concept, 2-arachidonyl glyceryl ether based biotinylated 3b enables direct visualization of CB(1) receptor in cells. These results represent the starting point for the development of advanced small molecule chemical probes able to generate valuable information about the cannabinoid receptors.

  16. GTKDynamo: a PyMOL plug-in for QC/MM hybrid potential simulations.

    PubMed

    Bachega, José Fernando R; Timmers, Luís Fernando S M; Assirati, Lucas; Bachega, Leonardo R; Field, Martin J; Wymore, Troy

    2013-09-30

    Hybrid quantum chemical/molecular mechanical (QCMM) potentials are very powerful tools for molecular simulation. They are especially useful for studying processes in condensed phase systems, such as chemical reactions that involve a relatively localized change in electronic structure and where the surrounding environment contributes to these changes but can be represented with more computationally efficient functional forms. Despite their utility, however, these potentials are not always straightforward to apply since the extent of significant electronic structure changes occurring in the condensed phase process may not be intuitively obvious. To facilitate their use, we have developed an open-source graphical plug-in, GTKDynamo that links the PyMOL visualization program and the pDynamo QC/MM simulation library. This article describes the implementation of GTKDynamo and its capabilities and illustrates its application to QC/MM simulations.

  17. The function of copulatory plugs in Caenorhabditis remanei: hints for female benefits

    PubMed Central

    2010-01-01

    Background Mating plugs that males place onto the female genital tract are generally assumed to prevent remating with other males. Mating plugs are usually explained as a consequence of male-male competition in multiply mating species. Here, we investigated whether mating plugs also have collateral effects on female fitness. These effects are negative when plugging reduces female mating rate below an optimum. However, plugging may also be positive when plugging prevents excessive forced mating and keeps mating rate closer to a females' optimum. Here, we studied these consequences in the gonochoristic nematode Caenorhabditis remanei. We employed a new CO2-sedation technique to interrupt matings before or after the production of a plug. We then measured mating rate, attractiveness and offspring number. Results The presence of a mating plug did not affect mating rate or attractiveness to roving males. Instead, females with mating plugs produced more offspring than females without copulatory plugs. Conclusions Our experiment suggests that plugging might have evolved under male-male competition but represents a poor protection against competing males in our experiment. Even if plugging does not reduce mating rate, our results indicate that females may benefit from being plugged in a different sense than remating prevention. PMID:21044286

  18. Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth: Part I: Chemical Diversity, Oxygen and Nitrogen Based Polymers.

    PubMed

    Wollrab, Eva; Scherer, Sabrina; Aubriet, Frédéric; Carré, Vincent; Carlomagno, Teresa; Codutti, Luca; Ott, Albrecht

    2016-06-01

    In a famous experiment Stanley Miller showed that a large number of organic substances can emerge from sparking a mixture of methane, ammonia and hydrogen in the presence of water (Miller, Science 117:528-529, 1953). Among these substances Miller identified different amino acids, and he concluded that prebiotic events may well have produced many of Life's molecular building blocks. There have been many variants of the original experiment since, including different gas mixtures (Miller, J Am Chem Soc 77:2351-2361, 1955; Oró Nature 197:862-867, 1963; Schlesinger and Miller, J Mol Evol 19:376-382, 1983; Miyakawa et al., Proc Natl Acad Sci 99:14,628-14,631, 2002). Recently some of Miller's remaining original samples were analyzed with modern equipment (Johnson et al. Science 322:404-404, 2008; Parker et al. Proc Natl Acad Sci 108:5526-5531, 2011) and a total of 23 racemic amino acids were identified. To give an overview of the chemical variety of a possible prebiotic broth, here we analyze a "Miller type" experiment using state of the art mass spectrometry and NMR spectroscopy. We identify substances of a wide range of saturation, which can be hydrophilic, hydrophobic or amphiphilic in nature. Often the molecules contain heteroatoms, with amines and amides being prominent classes of molecule. In some samples we detect ethylene glycol based polymers. Their formation in water requires the presence of a catalyst. Contrary to expectations, we cannot identify any preferred reaction product. The capacity to spontaneously produce this extremely high degree of molecular variety in a very simple experiment is a remarkable feature of organic chemistry and possibly prerequisite for Life to emerge. It remains a future task to uncover how dedicated, organized chemical reaction pathways may have arisen from this degree of complexity.

  19. Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth. Part I: Chemical Diversity, Oxygen and Nitrogen Based Polymers

    NASA Astrophysics Data System (ADS)

    Wollrab, Eva; Scherer, Sabrina; Aubriet, Frédéric; Carré, Vincent; Carlomagno, Teresa; Codutti, Luca; Ott, Albrecht

    2016-06-01

    In a famous experiment Stanley Miller showed that a large number of organic substances can emerge from sparking a mixture of methane, ammonia and hydrogen in the presence of water (Miller, Science 117:528-529, 1953). Among these substances Miller identified different amino acids, and he concluded that prebiotic events may well have produced many of Life's molecular building blocks. There have been many variants of the original experiment since, including different gas mixtures (Miller, J Am Chem Soc 77:2351-2361, 1955; Oró Nature 197:862-867, 1963; Schlesinger and Miller, J Mol Evol 19:376-382, 1983; Miyakawa et al., Proc Natl Acad Sci 99:14,628-14,631, 2002). Recently some of Miller's remaining original samples were analyzed with modern equipment (Johnson et al. Science 322:404-404, 2008; Parker et al. Proc Natl Acad Sci 108:5526-5531, 2011) and a total of 23 racemic amino acids were identified. To give an overview of the chemical variety of a possible prebiotic broth, here we analyze a "Miller type" experiment using state of the art mass spectrometry and NMR spectroscopy. We identify substances of a wide range of saturation, which can be hydrophilic, hydrophobic or amphiphilic in nature. Often the molecules contain heteroatoms, with amines and amides being prominent classes of molecule. In some samples we detect ethylene glycol based polymers. Their formation in water requires the presence of a catalyst. Contrary to expectations, we cannot identify any preferred reaction product. The capacity to spontaneously produce this extremely high degree of molecular variety in a very simple experiment is a remarkable feature of organic chemistry and possibly prerequisite for Life to emerge. It remains a future task to uncover how dedicated, organized chemical reaction pathways may have arisen from this degree of complexity.

  20. Stacked Pt/SrBi2Ta2-xNbxO9/Pt/IrOx/Ir Capacitor on Poly Plug

    NASA Astrophysics Data System (ADS)

    Kweon, Soon Yong; Choi, Si Kyung; Yang, Woo Seok; Yeom, Seung Jin; Roh, Jae Sung

    2002-01-01

    A Pt/SrBi2Ta2-xNbxO9(SBTN)/Pt/IrOx/Ir capacitor was successfully fabricated up to the stage of metal-1 etching process on a polysilicon plug for mega-bit ferroelectric random access memory. The integration processes include the chemical-mechanical polishing technique, buried TiN barrier structure and electrode technologies for high thermal stability, and a low-temperature process for SBTN film. The thickness of the iridium layer was the most important factor in controlling the contact resistance of the plug. The Pt thickness also affected the contact resistance of the plug. The best contact resistance of the plug was about 2.0 kΩ/plug at the maximum process temperature of 750°C for 3 min in oxygen ambient at the contact size of φ 0.30 μm. Hysteresis curves of the SBTN capacitor were obtained after the metal-1 etching process. The capacitor size dependency of the polarization was not observed in the range of 0.30-25 μm2 and the values of the sensing polarization were about 10 μC/cm2 at the applied voltage of 3 V@. In addition, the capacitor exhibited no fatigue loss up to 5× 1010 cycles at the switching voltage of 3 V.@

  1. Spatial and temporal variations of microbial community in a mixed plug-flow loop reactor fed with dairy manure

    PubMed Central

    Li, Yueh-Fen; Chen, Po-Hsu; Yu, Zhongtang

    2014-01-01

    Mixed plug-flow loop reactor (MPFLR) has been widely adopted by the US dairy farms to convert cattle manure to biogas. However, the microbiome in MPFLR digesters remains unexplored. In this study, the microbiome in a MPFLR digester operated on a mega-dairy farm was examined thrice over a 2 month period. Within 23 days of retention time, 55–70% of total manure solid was digested. Except for a few minor volatile fatty acids (VFAs), total VFA concentration and pH remained similar along the course of the digester and over time. Metagenomic analysis showed that although with some temporal variations, the bacterial community was rather stable spatially in the digester. The methanogenic community was also stable both spatially and temporally in the digester. Among methanogens, genus Methanosaeta dominated in the digester. Quantitative polymerase chain reaction (qPCR) analysis and metagenomic analysis yielded different relative abundance of individual genera of methanogens, especially for Methanobacterium, which was predominant based on qPCR analysis but undetectable by metagenomics. Collectively, the results showed that only small microbial and chemical gradients existed within the digester, and the digestion process occurred similarly throughout the MPFLR digester. The findings of this study may help improve the operation and design of this type of manure digesters. PMID:24690147

  2. Recent advancements in chemical luminescence-based lab-on-chip and microfluidic platforms for bioanalysis.

    PubMed

    Mirasoli, Mara; Guardigli, Massimo; Michelini, Elisa; Roda, Aldo

    2014-01-01

    Miniaturization of analytical procedures through microchips, lab-on-a-chip or micro total analysis systems is one of the most recent trends in chemical and biological analysis. These systems are designed to perform all the steps in an analytical procedure, with the advantages of low sample and reagent consumption, fast analysis, reduced costs, possibility of extra-laboratory application. A range of detection technologies have been employed in miniaturized analytical systems, but most applications relied on fluorescence and electrochemical detection. Chemical luminescence (which includes chemiluminescence, bioluminescence, and electrogenerated chemiluminescence) represents an alternative detection principle that offered comparable (or better) analytical performance and easier implementation in miniaturized analytical devices. Nevertheless, chemical luminescence-based ones represents only a small fraction of the microfluidic devices reported in the literature, and until now no review has been focused on these devices. Here we review the most relevant applications (since 2009) of miniaturized analytical devices based on chemical luminescence detection. After a brief overview of the main chemical luminescence systems and of the recent technological advancements regarding their implementation in miniaturized analytical devices, analytical applications are reviewed according to the nature of the device (microfluidic chips, microchip electrophoresis, lateral flow- and paper-based devices) and the type of application (micro-flow injection assays, enzyme assays, immunoassays, gene probe hybridization assays, cell assays, whole-cell biosensors).

  3. The prediction of toxic mode of action for environmental pollutants based on physico-chemical properties

    SciTech Connect

    Boxall, A.B.A. |; Watts, C.D.; Bresnen, G.M.; Dearden, J.C.; Scoffin, R.

    1995-12-31

    Aquatic ecosystems receive a wide range of potentially toxic contaminants. One approach to measure the environmental impact of these compounds is to perform costly and detailed experimental investigations. A quick and cost-effective alternative is to predict the likely effects of chemical contaminants using quantitative structure activity relationships (QSARs) which relate effects to chemical structure. One problem with the predictive approach is that QSARs can be established and used only for compounds with a common mode of toxic action. It is therefore important that a compound is assigned to the correct mode of action and that the correct QSAR is used. Two kinds of approach can be used to address this problem. In the first a compound is assigned to a class based on responses observed during experimental tests. The other approach uses chemical structural information e.g. the OECD method where compounds are classed as inert, less inert, reactive or specific acting based on chemical structure. The objective of this study was to determine whether compounds could be classified into one of the four OECD classes solely on the basis of their physico-chemical properties. Approximately 800 compounds were assigned to an OECD class and a range of properties were calculated. Discriminant analysis demonstrated that a large proportion of these compounds could be classified correctly based on two properties, namely a molecular connectivity index ({sup 2}{sub x}) and an electronic parameter (E{sub HOMO}).

  4. Bond strength: a comparison between chemical coated and mechanical interlock bases of ceramic and metal brackets.

    PubMed

    Wang, W N; Meng, C L; Tarng, T H

    1997-04-01

    Two types of chemically coated bases, two types of mechanical interlock base polycrystalline ceramic brackets, as well as one type of mechanical interlock base metal bracket were selected for bonding with Concise orthodontic resin on 60 extracted premolars. Bond strength was measured with an Instron testing machine and the debonded interface and enamel detachment were examined with scanning electron microscope and energy dispersive x-ray spectrometer. The results showed the greater bond strength with a chemically coated base of ceramic brackets had a greater debonded interface between enamel and resin, and the weaker bond strength of mechanical interlock base of ceramic and metal brackets had a greater debonded interfaces between bracket and resin. There was no significant statistical difference in bond strengths with mechanically interlock bases between ceramic and metal brackets. The enamel detachment was found on only the stronger bond strength in which there was a chemically coated base on the ceramic bracket. Ceramic bracket fractures were not found during debonding in this specially designed specimen with 1 mm/min speed of crosshead. The mechanical interlock base of the ceramic bracket combines the strength, durability and retention of a metal bracket along with an aesthetic advantage and no enamel detachment after debonding. PMID:9109582

  5. Commercializing light-duty plug-in/plug-out hydrogen-fuel-cell vehicles: "Mobile electricity" technologies, early California household markets, and innovation management

    NASA Astrophysics Data System (ADS)

    Williams, Brett David

    Starting from the premise that new consumer value must drive hydrogen-fuel-cell-vehicle (H2FCV) commercialization, a group of opportunities collectively called "Mobile Electricity" (Me-) is characterized. Me- redefines H2 FCVs as innovative products able to provide home recharging and mobile power, for example for tools, mobile activities, emergencies, and electric-grid-support services. To characterize such opportunities, this study first integrates and extends previous analyses of H2FCVs, plug-in hybrids, and vehicle-to-grid (V2G) power. It uses a new model to estimate zero-emission-power vs. zero-emission-driving tradeoffs, costs, and grid-support revenues for various electric-drive vehicle types and levels of infrastructure service. Next, the initial market potential for Me- enabled vehicles, such as H2FCVs and plug-in hybrids, is estimated by eliminating unlikely households from consideration for early adoption. 5.2 million of 33.9 million Californians in the 2000 Census live in households pre-adapted to Me-, 3.9 million if natural gas is required for home refueling. The possible sales base represented by this population is discussed. Several differences in demographic and other characteristics between the target market and the population as a whole are highlighted, and two issues related to the design of H2FCVs and their supporting infrastructure are discussed: vehicle range and home hydrogen refueling. These findings argue for continued investigation of this and similar target segments-which represent more efficient research populations for subsequent study by product designers and other decision-makers wishing to understand the early market dynamics facing Me- innovations. Next, Me-H2FCV commercialization issues are raised from the perspectives of innovation, product development, and strategic marketing. Starting with today's internalcombustion hybrids, this discussion suggests a way to move beyond the battery vs. fuel-cell zero-sum game and towards the

  6. A chemically powered unidirectional rotary molecular motor based on a palladium redox cycle

    NASA Astrophysics Data System (ADS)

    Collins, Beatrice S. L.; Kistemaker, Jos C. M.; Otten, Edwin; Feringa, Ben L.

    2016-09-01

    The conversion of chemical energy to drive directional motion at the molecular level allows biological systems, ranging from subcellular components to whole organisms, to perform a myriad of dynamic functions and respond to changes in the environment. Directional movement has been demonstrated in artificial molecular systems, but the fundamental motif of unidirectional rotary motion along a single-bond rotary axle induced by metal-catalysed transformation of chemical fuels has not been realized, and the challenge is to couple the metal-centred redox processes to stepwise changes in conformation to arrive at a full unidirectional rotary cycle. Here, we present the design of an organopalladium-based motor and the experimental demonstration of a 360° unidirectional rotary cycle using simple chemical fuels. Exploiting fundamental reactivity principles in organometallic chemistry enables control of directional rotation and offers the potential of harnessing the wealth of opportunities offered by transition-metal-based catalytic conversions to drive motion and dynamic functions.

  7. Mapping Proteome-Wide Targets of Environmental Chemicals Using Reactivity-Based Chemoproteomic Platforms.

    PubMed

    Medina-Cleghorn, Daniel; Bateman, Leslie A; Ford, Breanna; Heslin, Ann; Fisher, Karl J; Dalvie, Esha D; Nomura, Daniel K

    2015-10-22

    We are exposed to a growing number of chemicals in our environment, most of which have not been characterized in terms of their toxicological potential or mechanisms. Here, we employ a chemoproteomic platform to map the cysteine reactivity of environmental chemicals using reactivity-based probes to mine for hyper-reactive hotspots across the proteome. We show that environmental contaminants such as monomethylarsonous acid and widely used pesticides such as chlorothalonil and chloropicrin possess common reactivity with a distinct set of proteins. Many of these proteins are involved in key metabolic processes, suggesting that these targets may be particularly sensitive to environmental electrophiles. We show that the widely used fungicide chlorothalonil specifically inhibits several metabolic enzymes involved in fatty acid metabolism and energetics, leading to dysregulated lipid metabolism in mice. Our results underscore the utility of using reactivity-based chemoproteomic platforms to uncover novel mechanistic insights into the toxicity of environmental chemicals.

  8. Note: Dissolved hydrogen detection in power transformer oil based on chemically etched fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Jiang, Jun; Ma, Guo-ming; Song, Hong-tu; Zhou, Hong-yang; Li, Cheng-rong; Luo, Ying-ting; Wang, Hong-bin

    2015-10-01

    A fiber Bragg grating (FBG) sensor based on chemically etched cladding to detect dissolved hydrogen is proposed and studied in this paper. Low hydrogen concentration tests have been carried out in mixed gases and transformer oil to investigate the repeatability and sensitivity. Moreover, to estimate the influence of etched cladding thickness, a physical model of FBG-based hydrogen sensor is analyzed. Experimental results prove that thin cladding chemically etched by HF acid solution improves the response to hydrogen detection in oil effectively. At last, the sensitivity of FBG sensor chemically etched 16 μm could be as high as 0.060 pm/(μl/l), increased by more than 30% in comparison to un-etched FBG.

  9. Note: Dissolved hydrogen detection in power transformer oil based on chemically etched fiber Bragg grating.

    PubMed

    Jiang, Jun; Ma, Guo-ming; Song, Hong-tu; Zhou, Hong-yang; Li, Cheng-rong; Luo, Ying-ting; Wang, Hong-bin

    2015-10-01

    A fiber Bragg grating (FBG) sensor based on chemically etched cladding to detect dissolved hydrogen is proposed and studied in this paper. Low hydrogen concentration tests have been carried out in mixed gases and transformer oil to investigate the repeatability and sensitivity. Moreover, to estimate the influence of etched cladding thickness, a physical model of FBG-based hydrogen sensor is analyzed. Experimental results prove that thin cladding chemically etched by HF acid solution improves the response to hydrogen detection in oil effectively. At last, the sensitivity of FBG sensor chemically etched 16 μm could be as high as 0.060 pm/(μl/l), increased by more than 30% in comparison to un-etched FBG.

  10. Inline chemical process analysis in micro-plants based on thermoelectric flow and impedimetric sensors

    NASA Astrophysics Data System (ADS)

    Jacobs, T.; Kutzner, C.; Kropp, M.; Brokmann, G.; Lang, W.; Steinke, A.; Kienle, A.; Hauptmann, P.

    2010-10-01

    In micro-plants, as used in chemical micro-process engineering, an integrated inline analytics is regarded as an important factor for the development and optimization of chemical processes. Up to now, there is a lack of sensitive, robust and low-priced micro-sensors for monitoring mixing and chemical conversion in micro-fluidic channels. In this paper a novel sensor system combining an impedimetric sensor and a novel pressure stable thermoelectric flow sensor for monitoring chemical reactions in micro-plants is presented. The CMOS-technology-based impedimetric sensor mainly consists of two capacitively coupled interdigital electrodes on a silicon chip. The thermoelectric flow sensor consists of a heater in between two thermopiles on a perforated membrane. The pulsed and constant current feeds of the heater were analyzed. Both sensors enable the analysis of chemical conversion by means of changes in the thermal and electrical properties of the liquid. The homogeneously catalyzed synthesis of n-butyl acetate as a chemical model system was studied. Experimental results revealed that in an overpressure regime, relative changes of less than 1% in terms of thermal and electrical properties can be detected. Furthermore, the transition from one to two liquid phases accompanied by the change in slug flow conditions could be reproducibly detected.

  11. A FLUORESCENCE BASED ASSAY FOR DNA DAMAGE: INDUCED BY RADIATION, CHEMICALS AND ENZYMES

    EPA Science Inventory

    A simple and rapid assay to detect DNA damage is reported. This assay is based on the ability of certain dyes to fluoresce upon intercalation with dsDNA. Damage caused by ultraviolet (UV) radiation, chemicals or restriction enzymes is detected using this assay. UV radiation at...

  12. Rapid Prototyping of Chemical Microsensors Based on Molecularly Imprinted Polymers Synthesized by Two-Photon Stereolithography.

    PubMed

    Gomez, Laura Piedad Chia; Spangenberg, Arnaud; Ton, Xuan-Anh; Fuchs, Yannick; Bokeloh, Frank; Malval, Jean-Pierre; Tse Sum Bui, Bernadette; Thuau, Damien; Ayela, Cédric; Haupt, Karsten; Soppera, Olivier

    2016-07-01

    Two-photon stereolithography is used for rapid prototyping of submicrometre molecularly imprinted polymer-based 3D structures. The structures are evaluated as chemical sensing elements and their specific recognition properties for target molecules are confirmed. The 3D design capability is exploited and highlighted through the fabrication of an all-organic molecularly imprinted polymeric microelectromechanical sensor.

  13. Acid-base chemistry of white wine: analytical characterisation and chemical modelling.

    PubMed

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic "wine" especially adapted for testing.

  14. Raman spectroscopy-based detection of chemical contaminants in food powders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Raman spectroscopy technique has proven to be a reliable method for qualitative detection of chemical contaminants in food ingredients and products. For quantitative imaging-based detection, each contaminant particle in a food sample must be detected and it is important to determine the necessary sp...

  15. A Game-Based Approach to Learning the Idea of Chemical Elements and Their Periodic Classification

    ERIC Educational Resources Information Center

    Franco-Mariscal, Antonio Joaquín; Oliva-Martínez, José María; Blanco-López, Ángel; España-Ramos, Enrique

    2016-01-01

    In this paper, the characteristics and results of a teaching unit based on the use of educational games to learn the idea of chemical elements and their periodic classification in secondary education are analyzed. The method is aimed at Spanish students aged 15-16 and consists of 24 1-h sessions. The results obtained on implementing the teaching…

  16. CONCEPTUAL FRAMEWORK FOR THE CHEMICAL EFFECTS IN BIOLOGICAL SYSTEMS (CEBS) TOXICOGENOMICS KNOWLEDGE BASE

    EPA Science Inventory

    Conceptual Framework for the Chemical Effects in Biological Systems (CEBS) T oxicogenomics Knowledge Base

    Abstract
    Toxicogenomics studies how the genome is involved in responses to environmental stressors or toxicants. It combines genetics, genome-scale mRNA expressio...

  17. Improving Students' Chemical Literacy Levels on Thermochemical and Thermodynamics Concepts through a Context-Based Approach

    ERIC Educational Resources Information Center

    Cigdemoglu, Ceyhan; Geban, Omer

    2015-01-01

    The aim of this study was to delve into the effect of context-based approach (CBA) over traditional instruction (TI) on students' chemical literacy level related to thermochemical and thermodynamics concepts. Four eleventh-grade classes with 118 students in total taught by two teachers from a public high school in 2012 fall semester were enrolled…

  18. Rapid Prototyping of Chemical Microsensors Based on Molecularly Imprinted Polymers Synthesized by Two-Photon Stereolithography.

    PubMed

    Gomez, Laura Piedad Chia; Spangenberg, Arnaud; Ton, Xuan-Anh; Fuchs, Yannick; Bokeloh, Frank; Malval, Jean-Pierre; Tse Sum Bui, Bernadette; Thuau, Damien; Ayela, Cédric; Haupt, Karsten; Soppera, Olivier

    2016-07-01

    Two-photon stereolithography is used for rapid prototyping of submicrometre molecularly imprinted polymer-based 3D structures. The structures are evaluated as chemical sensing elements and their specific recognition properties for target molecules are confirmed. The 3D design capability is exploited and highlighted through the fabrication of an all-organic molecularly imprinted polymeric microelectromechanical sensor. PMID:27145145

  19. Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

    PubMed Central

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic “wine” especially adapted for testing. PMID:22566762

  20. STRESS PATHWAY-BASED REPORTER ASSAYS TO ASSESS TOXICITY OF ENVIRONMENTAL CHEMICALS.

    EPA Science Inventory

    There is an increasing need for assays for the rapid and efficient assessment of toxicities of large numbers of environmental chemicals. To meet this need, we are developing cell-based reporter assays that measure the activation of key molecular stress pathways. We are using pro...

  1. Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential

    PubMed Central

    Mitchell, Jade; Arnot, Jon A.; Jolliet, Olivier; Georgopoulos, Panos G.; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A.; Vallero, Daniel A.

    2014-01-01

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA’s need to develop novel approaches and tools for rapidly prioritizing chemicals, a “Challenge” was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA’s effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

  2. Pretreatment and integrated analysis of spectral data reveal seaweed similarities based on chemical diversity.

    PubMed

    Wei, Feifei; Ito, Kengo; Sakata, Kenji; Date, Yasuhiro; Kikuchi, Jun

    2015-03-01

    Extracting useful information from high dimensionality and large data sets is a major challenge for data-driven approaches. The present study was aimed at developing novel integrated analytical strategies for comprehensively characterizing seaweed similarities based on chemical diversity. The chemical compositions of 107 seaweed and 2 seagrass samples were analyzed using multiple techniques, including Fourier transform infrared (FT-IR) and solid- and solution-state nuclear magnetic resonance (NMR) spectroscopy, thermogravimetry-differential thermal analysis (TG-DTA), inductively coupled plasma-optical emission spectrometry (ICP-OES), CHNS/O total elemental analysis, and isotope ratio mass spectrometry (IR-MS). The spectral data were preprocessed using non-negative matrix factorization (NMF) and NMF combined with multivariate curve resolution-alternating least-squares (MCR-ALS) methods in order to separate individual component information from the overlapping and/or broad spectral peaks. Integrated analysis of the preprocessed chemical data demonstrated distinct discrimination of differential seaweed species. Further network analysis revealed a close correlation between the heavy metal elements and characteristic components of brown algae, such as cellulose, alginic acid, and sulfated mucopolysaccharides, providing a componential basis for its metal-sorbing potential. These results suggest that this integrated analytical strategy is useful for extracting and identifying the chemical characteristics of diverse seaweeds based on large chemical data sets, particularly complicated overlapping spectral data.

  3. Fragment-Based Electronic Structure Approach for Computing Nuclear Magnetic Resonance Chemical Shifts in Molecular Crystals.

    PubMed

    Hartman, Joshua D; Beran, Gregory J O

    2014-11-11

    First-principles chemical shielding tensor predictions play a critical role in studying molecular crystal structures using nuclear magnetic resonance. Fragment-based electronic structure methods have dramatically improved the ability to model molecular crystal structures and energetics using high-level electronic structure methods. Here, a many-body expansion fragment approach is applied to the calculation of chemical shielding tensors in molecular crystals. First, the impact of truncating the many-body expansion at different orders and the role of electrostatic embedding are examined on a series of molecular clusters extracted from molecular crystals. Second, the ability of these techniques to assign three polymorphic forms of the drug sulfanilamide to the corresponding experimental (13)C spectra is assessed. This challenging example requires discriminating among spectra whose (13)C chemical shifts differ by only a few parts per million (ppm) across the different polymorphs. Fragment-based PBE0/6-311+G(2d,p) level chemical shielding predictions correctly assign these three polymorphs and reproduce the sulfanilamide experimental (13)C chemical shifts with 1 ppm accuracy. The results demonstrate that fragment approaches are competitive with the widely used gauge-invariant projector augmented wave (GIPAW) periodic density functional theory calculations. PMID:26584373

  4. Pretreatment and integrated analysis of spectral data reveal seaweed similarities based on chemical diversity.

    PubMed

    Wei, Feifei; Ito, Kengo; Sakata, Kenji; Date, Yasuhiro; Kikuchi, Jun

    2015-03-01

    Extracting useful information from high dimensionality and large data sets is a major challenge for data-driven approaches. The present study was aimed at developing novel integrated analytical strategies for comprehensively characterizing seaweed similarities based on chemical diversity. The chemical compositions of 107 seaweed and 2 seagrass samples were analyzed using multiple techniques, including Fourier transform infrared (FT-IR) and solid- and solution-state nuclear magnetic resonance (NMR) spectroscopy, thermogravimetry-differential thermal analysis (TG-DTA), inductively coupled plasma-optical emission spectrometry (ICP-OES), CHNS/O total elemental analysis, and isotope ratio mass spectrometry (IR-MS). The spectral data were preprocessed using non-negative matrix factorization (NMF) and NMF combined with multivariate curve resolution-alternating least-squares (MCR-ALS) methods in order to separate individual component information from the overlapping and/or broad spectral peaks. Integrated analysis of the preprocessed chemical data demonstrated distinct discrimination of differential seaweed species. Further network analysis revealed a close correlation between the heavy metal elements and characteristic components of brown algae, such as cellulose, alginic acid, and sulfated mucopolysaccharides, providing a componential basis for its metal-sorbing potential. These results suggest that this integrated analytical strategy is useful for extracting and identifying the chemical characteristics of diverse seaweeds based on large chemical data sets, particularly complicated overlapping spectral data. PMID:25647718

  5. Sensing structure based on surface plasmonic resonance in single mode optical fibers chemically etched

    NASA Astrophysics Data System (ADS)

    Coelho, L.; Almeida, J. M.; Santos, J. L.; Ferreira, R. A. S.; André, P. S.; Viegas, D.

    2013-05-01

    Many optical systems based on Surface Plasmon Resonance (SPR) have been developed for work as refractometers, chemical sensors or even for measure the thickness of metal and dielectric thin films. These kinds of systems are usually large, expensive and cannot be used for remote sensing. Optical fiber sensors based on SPR has been widely studied for the last 20 years with several configurations mostly using multimode optical fibers with large cores and plastic claddings. Sensors based on SPR present very high sensitivity to refractive index variations when compared to the traditional refractive index sensors. Here we propose a SPR sensor based in a single mode fiber. The fiber end is chemically etched by emersion in a 48% hydrofluoric acid solution, resulting a single mode fiber with the cladding removed in a small section. A resonance dip around 1580 nm was attained in good agreement with the simulation scenario that takes into account the real characteristics of the fiber.

  6. Plug-In Electric Vehicle Handbook for Fleet Managers (Brochure)

    SciTech Connect

    Not Available

    2012-04-01

    Plug-in electric vehicles (PEVs) are entering the automobile market and are viable alternatives to conventional vehicles. This guide for fleet managers describes the basics of PEV technology, PEV benefits for fleets, how to select the right PEV, charging a PEV, and PEV maintenance.

  7. Analysis of supersonic plug nozzle flowfield and heat transfer

    NASA Technical Reports Server (NTRS)

    Murthy, S. N. B.; Sheu, W. H.

    1988-01-01

    A number of problems pertaining to the flowfield in a plug nozzle, designed as a supersonic thruster nozzle, with provision for cooling the plug with a coolant stream admitted parallel to the plug wall surface, were studied. First, an analysis was performed of the inviscid, nonturbulent, gas dynamic interaction between the primary hot stream and the secondary coolant stream. A numerical prediction code for establishing the resulting flowfield with a dividing surface between the two streams, for various combinations of stagnation and static properties of the two streams, was utilized for illustrating the nature of interactions. Secondly, skin friction coefficient, heat transfer coefficient and heat flux to the plug wall were analyzed under smooth flow conditions (without shocks or separation) for various coolant flow conditions. A numerical code was suitably modified and utilized for the determination of heat transfer parameters in a number of cases for which data are available. Thirdly, an analysis was initiated for modeling turbulence processes in transonic shock-boundary layer interaction without the appearance of flow separation.

  8. Plug-In Electric Vehicle Handbook for Consumers (Brochure)

    SciTech Connect

    Not Available

    2011-09-01

    Plug-in electric vehicles (PEVs) are entering the automobile market and are viable alternatives to conventional vehicles. This guide for consumers describes the basics of PEV technology, PEV benefits, how to select the right PEV, charging a PEV, and PEV maintenance.

  9. Transient motion of mucus plugs in respiratory airways

    NASA Astrophysics Data System (ADS)

    Zamankhan, Parsa; Hu, Yingying; Helenbrook, Brian; Takayama, Shuichi; Grotberg, James B.

    2011-11-01

    Airway closure occurs in lung diseases such as asthma, cystic fibrosis, or emphysema which have an excess of mucus that forms plugs. The reopening process involves displacement of mucus plugs in the airways by the airflow of respiration. Mucus is a non-Newtonian fluid with a yield stress; therefore its behavior can be approximated by a Bingham fluid constitutive equation. In this work the reopening process is approximated by simulation of a transient Bingham fluid plug in a 2D channel. The governing equations are solved by an Arbitrary Lagrangian Eulerian (ALE) finite element method through an in-house code. The constitutive equation for the Bingham fluid is implemented through a regularization method. The effects of the yield stress on the flow features and wall stresses are discussed with applications to potential injuries to the airway epithelial cells which form the wall. The minimum driving pressure for the initiation of the motion is computed and its value is related to the mucus properties and the plug shape. Supported by HL84370 and HL85156.

  10. 6. Front of northern kiln group, looking west. Vents, plugged ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Front of northern kiln group, looking west. Vents, plugged with loose bricks and clay, are distinguishable in the nearest and farthest kilns, slightly above current grade. - Warren King Charcoal Kilns, 5 miles west of Idaho Highway 28, Targhee National Forest, Leadore, Lemhi County, ID

  11. Inert plug formation in the DDT of granular energetic materials

    SciTech Connect

    Son, S.F.; Asay, B.W.; Bdzil, J.B.

    1996-05-01

    A mechanism is proposed to explain the {open_quotes}plugs{close_quotes} that have been observed in deflagration-to-detonation transition (DDT) of granular explosives. Numerical simulations are performed that demonstrate the proposed mechanism. Observed trends are reproduced. {copyright} {ital 1996 American Institute of Physics.}

  12. Plug-in Sensors for Air Pollution Monitoring.

    ERIC Educational Resources Information Center

    Shaw, Manny

    Faristors, a type of plug-in sensors used in analyzing equipment, are described in this technical report presented at the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971. Their principles of operation, interchangeability, and versatility for measuring air pollution at…

  13. Seating tool for preparing molded-plug terminations on FCC

    NASA Technical Reports Server (NTRS)

    Chambers, C. M.; Corum, C. C.

    1971-01-01

    Hand-operated tool positions and seats window piece and conductor spacer onto conductors of two stripped cables during process of terminating cables with molded plug. Tool accommodates cables up to 3 in. wide and is used in conjunction with folding tools.

  14. Valley plugs, land use, and phytogeomorphic response: Chapter 14

    USGS Publications Warehouse

    Pierce, A.R.; King, Sammy L.; Shroder, John F.

    2013-01-01

    Anthropogenic alteration of fluvial systems can disrupt functional processes that provide valuable ecosystem services. Channelization alters fluvial parameters and the connectivity of river channels to their floodplains which is critical for productivity, nutrient cycling, flood control, and biodiversity. The effects of channelization can be exacerbated by local geology and land-use activities, resulting in dramatic geomorphic readjustments including the formation of valley plugs. Considerable variation in the response of abiotic processes, including surface hydrology, subsurface hydrology, and sedimentation dynamics, to channelization and the formation of valley plugs. Altered abiotic processes associated with these geomorphic features and readjustments influence biotic processes including species composition, abundance, and successional processes. Considerable interest exists for restoring altered fluvial systems and their floodplains because of their social and ecological importance. Understanding abiotic and biotic responses of channelization and valley-plug formation within the context of the watershed is essential to successful restoration. This chapter focuses on the primary causes of valley-plug formation, resulting fluvial-geomorphic responses, vegetation responses, and restoration and research needs for these systems.

  15. Tandem-mirror end plugs for future fusion reactors

    NASA Astrophysics Data System (ADS)

    1981-06-01

    Electrostatic fields for confining central-cell plasma are achieved by heating the electrons in end-plugs via electron-cyclotron-resonance heating. Four end-plug magnetic configurations are being developed and tested to determine which will provide the best thermal barrier between plug- and central-cell electrons in a fusion reactor: (1) the inside barrier, with its auxiliary solenoid; (2) the auxiliary-mirror-cell (A-cell) barrier, which makes use of C-shaped magnet coils; (3) the axisymmetric-cusp barrier, using circular coils; and (4) the electron-ring barrier, in which two magnetic coils are stabilized by a ring of hot electrons. Calculations of the magnetohydrodynamic (MHD) stability are being performed with respect to the magnetic curvatures of each end-plug configuration. Models for describing the behavior of plasmas with finite ion orbits are being developed to predict MHD stability. Charge-exchange pumping systems for reactors with inside, A-cell, and axisymmetric-cusp barriers have already been designed, and a pumping system for removing thermalized helium ions is being explored.

  16. Axicell design for the end plugs of MFTF-B

    SciTech Connect

    Thomassen, K.I.; Karpenko, V.N.

    1982-04-23

    Certain changes in the end-plug design in the Mirror Fusion Test Facility (MFTF-B) are described. The Laboratory (LLNL) proposes to implement these changes as soon as possible in order to construct the machine in an axicell configuration. The present physics and technology goals as well as the project cost and schedule will not be affected by these changes.

  17. 40 CFR 146.92 - Injection well plugging.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Injection well plugging. 146.92 Section 146.92 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) UNDERGROUND INJECTION CONTROL PROGRAM: CRITERIA AND STANDARDS Criteria and Standards...

  18. Fiscal year 1993 well plugging and abandonment program, Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    Not Available

    1993-09-01

    This report is a synopsis of the progress of the well plugging and abandonment program at the Y-12 Plant, Oak Ridge, Tennessee, from December 1992 through August 20, 1993. A total of 70 wells and borings were plugged and abandoned during the period of time covered in this report. All wells and borings were plugged and abandoned in accordance with the Monitoring Well Plugging and Abandonment Plan for the US Department of Energy, Y-12 Plant, Oak Ridge, Tennessee (HSW, Inc. 1991).

  19. Fiscal Year 1993 Well Plugging and Abandonment Program Summary Report Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    1994-09-01

    This report is a synopsis of the progress of the well plugging and abandonment program at the Y-12 Plant, Oak Ridge, Tennessee, from October 1993 through August 1994. A total of 57 wells and borings were plugged and abandoned during the period of time covered in this report. All wells and borings were plugged and abandoned in accordance with the Monitoring Well Plugging and Abandonment Plan for the U.S. Department of Energy, Y-12 Plant, Oak Ridge, Tennessee.

  20. Aeroacoustics of contoured and solid/porous conical plug-nozzle supersonic jet flows

    NASA Technical Reports Server (NTRS)

    Dosanjh, D. S.; Das, I. S.

    1985-01-01

    The acoustic far field, the shock-associated noise and characteristics of the repetitive shock structure of supersonic jet flows issuing from a contoured plug-nozzle and uncontoured plug-nozzle having a short conical plug of either a solid or a combination of solid/porous surface with pointed termination operated at a range of supercritical pressure are reported. The contoured and the uncontoured plug-nozzles had the same throat area and the same annular-radius ratio.

  1. The PubChem chemical structure sketcher.

    PubMed

    Ihlenfeldt, Wolf D; Bolton, Evan E; Bryant, Stephen H

    2009-12-17

    PubChem is an important public, Web-based information source for chemical and bioactivity information. In order to provide convenient structure search methods on compounds stored in this database, one mandatory component is a Web-based drawing tool for interactive sketching of chemical query structures. Web-enabled chemical structure sketchers are not new, being in existence for years; however, solutions available rely on complex technology like Java applets or platform-dependent plug-ins. Due to general policy and support incident rate considerations, Java-based or platform-specific sketchers cannot be deployed as a part of public NCBI Web services. Our solution: a chemical structure sketching tool based exclusively on CGI server processing, client-side JavaScript functions, and image sequence streaming. The PubChem structure editor does not require the presence of any specific runtime support libraries or browser configurations on the client. It is completely platform-independent and verified to work on all major Web browsers, including older ones without support for Web2.0 JavaScript objects.

  2. Array-based sensing with nanoparticles: “Chemical noses” for sensing biomolecules and cell surfaces

    PubMed Central

    Miranda, Oscar R.; Creran, Brian; Rotello, Vincent M.

    2010-01-01

    Nanoparticle-based arrays have been used to distinguish a wide range of biomolecular targets through pattern recognition. In this report, we highlight new “chemical nose” methodologies that use nanoparticle systems to provide high sensitivity sensing of biomolecular targets, including fluorescent polymer/gold nanoparticle complexes that can discriminate between different bioanalytes including proteins, bacteria, and mammalian cells as well as dye-based micellar systems for the detection of clinically important metallo- and non-metallo proteins. PMID:20801707

  3. High-performance NO2 sensors based on chemically modified graphene.

    PubMed

    Yuan, Wenjing; Liu, Anran; Huang, Liang; Li, Chun; Shi, Gaoquan

    2013-02-01

    Covalently grafting reduced graphene oxide (rGO) sheets with sulfophenyl or ethylenediamine groups can produce chemically modified graphene (CMG) for fabricating high-performance gas sensors. The NO(2) sensors based on these CMGs exhibit sensitivities 4 to 16 times higher than that of a sensor based on rGO. They also show excellent selectivity and repeatability without the aid of UV-light or thermal treatment. PMID:23139053

  4. Planning for chemical incidents by implementing a Delphi based consensus study

    PubMed Central

    Crawford, I; Mackway-Jones, K; Russell, D; Carley, S

    2004-01-01

    This paper provides a practical approach to the difficulties surrounding planning for chemical incidents, based upon the results of a Delphi based consensus study. It is intended to offer advice, which can be implemented at regional and local prehospital and hospital level. The phases of the response that are covered include preparation, management of the incident, delivery of medical support during the incident, and recovery and support after the incident. PMID:14734368

  5. Experts workshop on the ecotoxicological risk assessment of ionizable organic chemicals: Towards a science-based framework for chemical assessment

    EPA Science Inventory

    There is a growing need to develop analytical methods and tools that can be applied to assess the environmental risks associated with charged, polar, and ionisable organic chemicals, such as those used as active pharmaceutical ingredients, biocides, and surface active chemicals. ...

  6. Physical and chemical mechanisms in oxide-based resistance random access memory.

    PubMed

    Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Zhang, Rui; Hung, Ya-Chi; Syu, Yong-En; Chang, Yao-Feng; Chen, Min-Chen; Chu, Tian-Jian; Chen, Hsin-Lu; Pan, Chih-Hung; Shih, Chih-Cheng; Zheng, Jin-Cheng; Sze, Simon M

    2015-01-01

    In this review, we provide an overview of our work in resistive switching mechanisms on oxide-based resistance random access memory (RRAM) devices. Based on the investigation of physical and chemical mechanisms, we focus on its materials, device structures, and treatment methods so as to provide an in-depth perspective of state-of-the-art oxide-based RRAM. The critical voltage and constant reaction energy properties were found, which can be used to prospectively modulate voltage and operation time to control RRAM device working performance and forecast material composition. The quantized switching phenomena in RRAM devices were demonstrated at ultra-cryogenic temperature (4K), which is attributed to the atomic-level reaction in metallic filament. In the aspect of chemical mechanisms, we use the Coulomb Faraday theorem to investigate the chemical reaction equations of RRAM for the first time. We can clearly observe that the first-order reaction series is the basis for chemical reaction during reset process in the study. Furthermore, the activation energy of chemical reactions can be extracted by changing temperature during the reset process, from which the oxygen ion reaction process can be found in the RRAM device. As for its materials, silicon oxide is compatible to semiconductor fabrication lines. It is especially promising for the silicon oxide-doped metal technology to be introduced into the industry. Based on that, double-ended graphene oxide-doped silicon oxide based via-structure RRAM with filament self-aligning formation, and self-current limiting operation ability is demonstrated. The outstanding device characteristics are attributed to the oxidation and reduction of graphene oxide flakes formed during the sputter process. Besides, we have also adopted a new concept of supercritical CO2 fluid treatment to efficiently reduce the operation current of RRAM devices for portable electronic applications.

  7. 40 CFR 147.3108 - Plugging Class I, II, and III wells.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with a cement plug from there to at least one hundred (100) feet above the top of the disposal or injection zone. (2) A cement plug shall also be set from a point at least fifty (50) feet below the shoe of... cement plug shall extend from a point at least thirty feet below the ground surface to a point five...

  8. 40 CFR 147.3108 - Plugging Class I, II, and III wells.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with a cement plug from there to at least one hundred (100) feet above the top of the disposal or injection zone. (2) A cement plug shall also be set from a point at least fifty (50) feet below the shoe of... cement plug shall extend from a point at least thirty feet below the ground surface to a point five...

  9. 30 CFR 250.1713 - Must I notify MMS before I begin well plugging operations?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Must I notify MMS before I begin well plugging operations? 250.1713 Section 250.1713 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE... Activities Permanently Plugging Wells § 250.1713 Must I notify MMS before I begin well plugging...

  10. 30 CFR 250.1711 - When will MMS order me to permanently plug a well?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When will MMS order me to permanently plug a well? 250.1711 Section 250.1711 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE... Activities Permanently Plugging Wells § 250.1711 When will MMS order me to permanently plug a well? MMS...

  11. 40 CFR 144.62 - Cost estimate for plugging and abandonment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... abandonment. 144.62 Section 144.62 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Waste Injection Wells § 144.62 Cost estimate for plugging and abandonment. (a) The owner or operator... accordance with the plugging and abandonment plan as specified in §§ 144.28 and 144.51. The plugging...

  12. 40 CFR 144.62 - Cost estimate for plugging and abandonment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... abandonment. 144.62 Section 144.62 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Waste Injection Wells § 144.62 Cost estimate for plugging and abandonment. (a) The owner or operator... accordance with the plugging and abandonment plan as specified in §§ 144.28 and 144.51. The plugging...

  13. 40 CFR 144.62 - Cost estimate for plugging and abandonment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... abandonment. 144.62 Section 144.62 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Waste Injection Wells § 144.62 Cost estimate for plugging and abandonment. (a) The owner or operator... accordance with the plugging and abandonment plan as specified in §§ 144.28 and 144.51. The plugging...

  14. 40 CFR 144.62 - Cost estimate for plugging and abandonment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... abandonment. 144.62 Section 144.62 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... Waste Injection Wells § 144.62 Cost estimate for plugging and abandonment. (a) The owner or operator... accordance with the plugging and abandonment plan as specified in §§ 144.28 and 144.51. The plugging...

  15. PLUG STORAGE BUILDING, TRA611, AWAITS SHIELDING SOIL TO BE PLACED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PLUG STORAGE BUILDING, TRA-611, AWAITS SHIELDING SOIL TO BE PLACED OVER PLUG STORAGE TUBES. WING WALLS WILL SUPPORT EARTH FILL. MTR, PROCESS WATER BUILDING, AND WORKING RESERVOIR IN VIEW BEYOND PLUG STORAGE. CAMERA FACES NORTHEAST. INL NEGATIVE NO. 2949. Unknown Photographer, 7/30/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  16. 40 CFR 144.62 - Cost estimate for plugging and abandonment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Cost estimate for plugging and... Waste Injection Wells § 144.62 Cost estimate for plugging and abandonment. (a) The owner or operator must prepare a written estimate, in current dollars, of the cost of plugging the injection well...

  17. 30 CFR 250.1711 - When will BSEE order me to permanently plug a well?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... well? 250.1711 Section 250.1711 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Decommissioning Activities Permanently Plugging Wells § 250.1711 When will BSEE order me to permanently plug a well? BSEE will order you to permanently plug a well if that well: (a) Poses a hazard to safety or...

  18. 30 CFR 250.1711 - When will BSEE order me to permanently plug a well?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... well? 250.1711 Section 250.1711 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Decommissioning Activities Permanently Plugging Wells § 250.1711 When will BSEE order me to permanently plug a well? BSEE will order you to permanently plug a well if that well: (a) Poses a hazard to safety or...

  19. 30 CFR 250.1711 - When will BSEE order me to permanently plug a well?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... well? 250.1711 Section 250.1711 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Decommissioning Activities Permanently Plugging Wells § 250.1711 When will BSEE order me to permanently plug a well? BSEE will order you to permanently plug a well if that well: (a) Poses a hazard to safety or...

  20. The Bases of Chemical Thermodynamics, Volumes 1 and 2 by Michael Graetzel and Pierre Infelta

    NASA Astrophysics Data System (ADS)

    van Hecke, Gerald R.

    2001-09-01

    calculated and not trying to discuss randomness, which cannot. The second law is introduced via traditional heat engines with arguments as thorough as those of K. G. Denbigh in his classic Chemical Thermodynamics text. However, the authors use quite different examples, which are highly readable. The overworked term "entropy of the universe" has been abandoned in favor of "global entropy", meaning a combination of the system and surroundings. The term works for me. In addition to the Carnot cycle, there are compelling expositions on the Otto, Stirling, and Joule cycles. When discussing chemical reactions, extensive use is made of the extent of reaction concept. In fact a very clever derivation of the temperature dependencies of DrG°, DrH°, and DrS° is offered using the temperature dependency of the extent of reaction. Still on the topic of chemical equilibrium, the authors provide an example (and make the point quite clearly) of how in cases involving simultaneous chemical equilibria, it is quite possible to drive a reaction with a positive DrG° toward completion through the device of coupling the reaction with other favorable reactions. For biochemical systems this is the reason for life. Having (I hope) intrigued the reader of this review to this point, I'd better describe something more of the text. The two volumes would need to be used as companions in the sense that while Volume 1 could be used alone, Volume 2 definitely refers to crucial material contained in Volume 1. The separation into two volumes does seem a bit odd; and in fact, the volumes are continuously numbered. Each volume contains fully worked-out examples pertinent to the material in that volume. The examples, which the authors call problems but that is a stretch, are not the typical three-line, use the formula, plug-and-chug variety, but very elaborate applications of the principles discussed in the text. The examples could be studied on their own, without the benefit of the text. The text proper has

  1. Alternate tube plugging criteria for steam generator tubes

    SciTech Connect

    Cueto-Felgueroso, C.; Aparicio, C.B.

    1997-02-01

    The tubing of the Steam Generators constitutes more than half of the reactor coolant pressure boundary. Specific requirements governing the maintenance of steam generator tubes integrity are set in Plant Technical Specifications and in Section XI of the ASME Boiler and Pressure Vessel Code. The operating experience of Steam Generator tubes of PWR plants has shown the existence of some types of degradatory processes. Every one of these has an specific cause and affects one or more zones of the tubes. In the case of Spanish Power Plants, and depending on the particular Plant considered, they should be mentioned the Primary Water Stress Corrosion Cracking (PWSCC) at the roll transition zone (RTZ), the Outside Diameter Stress Corrosion Cracking (ODSCC) at the Tube Support Plate (TSP) intersections and the fretting with the Anti-Vibration Bars (AVBs) or with the Support Plates in the preheater zone. The In-Service Inspections by Eddy Currents constitutes the standard method for assuring the SG tubes integrity and they permit the monitoring of the defects during the service life of the plant. When the degradation reaches a determined limit, called the plugging limit, the SG tube must be either repaired or retired from service by plugging. Customarily, the plugging limit is related to the depth of the defect. Such depth is typically 40% of the wall thickness of the tube and is applicable to any type of defect in the tube. In its origin, that limit was established for tubes thinned by wastage, which was the predominant degradation in the seventies. The application of this criterion for axial crack-like defects, as, for instance, those due to PWSCC in the roll transition zone, has lead to an excessive and unnecessary number of tubes being plugged. This has lead to the development of defect specific plugging criteria. Examples of the application of such criteria are discussed in the article.

  2. The porous-plug burner: Flame stabilization, onset of oscillation, and restabilization

    SciTech Connect

    Kurdyumov, Vadim N.; Matalon, Moshe

    2008-04-15

    In recent studies of edge-flames it was found that when the characteristic gas velocity exceeds a critical value the flame often undergoes spontaneous oscillations. The oscillations are amplified as the flow rate increases, reaching a maximum amplitude, and then decrease with further increasing flow rate until the flame restabilizes. In this paper we examine the concept of flame restabilization in a simpler but related problem - the planar premixed flame on a porous-plug burner - which is amenable to a full stability analysis. We show the dependence of all possible steady states on the relevant parameters, including the mass flow rate, the effective Lewis number of the mixture, the overall activation energy of the chemical reaction, and the extent of heat release. A linear stability analysis is then carried out to examine whether these steady states are stable to small disturbances. The analysis determines the critical conditions for the onset of instability, as well as the nature of the instability. In particular, we show that by decreasing the mass flow rate, the flame, which is at first stable, starts to oscillate back and forth for a limited range of gas velocities but is then restabilized by further decreasing the mass flow rate. We also show that the properties of the plug, such as the thickness of the plate and its porosity, play a significant role in flame stabilization. (author)

  3. A Compact, Low-Power Cantilever-Based Sensor Array for Chemical Detection

    SciTech Connect

    Loui, A; Ratto, T; Wilson, T; Mukerjee, E; Hu, Z; Sulchek, T; Hart, B

    2007-02-22

    A compact and low-power cantilever-based sensor array has been developed and used to detect various vapor analytes. This device employs sorptive polymers that are deposited onto piezoresistive cantilevers. We have successfully detected several organic vapors, representing a breadth of chemical properties and over a range of concentrations. Comparisons of the polymer/vapor partition coefficient to the cantilever deflection responses show that a simple linear relationship does not exist, emphasizing the need to develop an appropriate functional model to describe the chemical-to-mechanical transduction that is unique to this sensing modality.

  4. Evaluating the antioxidant capacity of natural products: a review on chemical and cellular-based assays.

    PubMed

    López-Alarcón, Camilo; Denicola, Ana

    2013-02-01

    Oxidative stress is associated with several pathologies like cardiovascular, neurodegenerative, cancer and even aging. It has been suggested that a diet rich in antioxidants would be beneficial to human health and a lot of interest is focused on the determination of antioxidant capacity of natural products. Different chemical methods have been developed including the popular ORAC that evaluates the potential of a sample as inhibitor of a target molecule oxidation. Chemical-based methods are useful for screening, they are low cost, high-throughput and yield an index value (expressed as equivalents of Trolox) that allows comparing and ordering different products. More recently, nanoparticles-based assays have been developed to sense the antioxidant power of natural products. However, the antioxidant capacity indexes obtained by chemical assays cannot extrapolate the performance of the sample in vivo. Considering that antioxidant action is not limited to scavenging free radicals but includes upregulation of antioxidant and detoxifying enzymes, modulation of redox cell signaling and gene expression, it is necessary to move to cellular assays in order to evaluate the potential antioxidant activity of a compound or extract. Animal models and human studies are more appropriate but also more expensive and time-consuming, making the cell culture assays very attractive as intermediate testing methods. Cellular antioxidant activity (CAA) assays, activation of redox transcription factors, inhibition of oxidases or activation of antioxidant enzymes are reviewed and compared with the classical in vitro chemical-based assays for evaluation of antioxidant capacity of natural products.

  5. Plug-In Hybrid Urban Delivery Truck Technology Demonstration

    SciTech Connect

    Miyasato, Matt; Impllitti, Joseph; Pascal, Amar

    2015-07-31

    The I-710 and CA-60 highways are key transportation corridors in the Southern California region that are heavily used on a daily basis by heavy duty drayage trucks that transport the cargo from the ports to the inland transportation terminals. These terminals, which include store/warehouses, inland-railways, are anywhere from 5 to 50 miles in distance from the ports. The concentrated operation of these drayage vehicles in these corridors has had and will continue to have a significant impact on the air quality in this region whereby significantly impacting the quality of life in the communities surrounding these corridors. To reduce these negative impacts it is critical that zero and near-zero emission technologies be developed and deployed in the region. A potential local market size of up to 46,000 trucks exists in the South Coast Air Basin, based on near- dock drayage trucks and trucks operating on the I-710 freeway. The South Coast Air Quality Management District (SCAQMD), California Air Resources Board (CARB) and Southern California Association of Governments (SCAG) — the agencies responsible for preparing the State Implementation Plan required under the federal Clean Air Act — have stated that to attain federal air quality standards the region will need to transition to broad use of zero and near zero emission energy sources in cars, trucks and other equipment (Southern California Association of Governments et al, 2011). SCAQMD partnered with Volvo Trucks to develop, build and demonstrate a prototype Class 8 heavy-duty plug-in hybrid drayage truck with significantly reduced emissions and fuel use. Volvo’s approach leveraged the group’s global knowledge and experience in designing and deploying electromobility products. The proprietary hybrid driveline selected for this proof of concept was integrated with multiple enhancements to the complete vehicle in order to maximize the emission and energy impact of electrification. A detailed review of all

  6. Dynamics of coalescence of plugs with a hydrophilic wetting layer induced by flow in a microfluidic chemistrode.

    PubMed

    Liu, Ying; Ismagilov, Rustem F

    2009-03-01

    This manuscript analyzes the dynamics of coalescence of an incoming aqueous plug with a wetting layer above a hydrophilic surface in the chemistrode. The chemistrode is a recently described (Chen, D.; Du, W.; Liu, Y.; Liu, W.; Kuznetsov, A.; Mendez, F. E.; Philipson, L. H.; Ismagilov, R. F. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 16843-16848) microfluidic analogue of an electrode, but operating at the chemical rather than electrical level, developed with the aim of capturing local stimulus-response processes in chemistry and biology. The chemistrode consists of open-ended V-shaped microfluidic channels that can be brought into contact with a chemical or biological hydrophilic substrate. The chemistrode relies on multiphase aqueous/fluorous flow and uses plugs to achieve high temporal resolution of stimulation and sampling. Coalescence of the incoming plugs, containing the stimuli, with the liquid in the wetting layer is required for chemical exchange to take place in the chemistrode. Here, we investigate the system with triethyleneglycol mono[1H,1H-perfluorooctyl]ether RfOEG as the surfactant. This surfactant was necessary to prevent nonspecific absorption of proteins to the aqueous fluorous interface and to ensure biocompatibility of the system, but too much surfactant increased the barrier for coalescence. In this system, coalescence was controlled by the capillary number. At a higher value of the capillary number, coalescence took more time, and deformation of the interface of the incoming plug and the wetting layer was more significant. Above a critical capillary number, coalescence did not occur between the incoming plug and the wetting layer. The critical capillary number was an increasing function of surface tension but was independent of viscosity ratio. Coalescence was surprisingly reproducible, presumably because film rupture during coalescence was reliably initiated at the hydrophilic substrate. These results are useful in rational operation of the

  7. Versatile materials for use as chemically sensitive interfaces in SAW-based sensor arrays

    SciTech Connect

    Crooks, R.M.; Bergbrieter, D.E.; Bruening, M.L.; Wells, M.; Zhou, Yuefen; Ricco, A.J.; Osbourn, G.C.

    1996-07-01

    The primary research objective of the work described here is to design, synthesize, and characterize new materials for use as chemical sensor interfaces, integrate these materials, using appropriate transducers, into sensor arrays, and then develop appropriate mathematical algorithms for interpreting the array response. In this paper, we will discuss two new types of materials we have developed that are ideally suited for use as chemically sensitive interfaces for array-based chemical sensing applications, since they: (1) provide general specificity towards classes of functional groups rather than individual compounds; (2) are intermediate in structure between monolayers and polymers; (3) exhibit both endo- and exo-recognition. The first class of materials is surface-confined dendrimers and the second is hyperbranched polymers.

  8. Target Fishing for Chemical Compounds using Target-Ligand Activity data and Ranking based Methods

    PubMed Central

    Wale, Nikil; Karypis, George

    2009-01-01

    In recent years the development of computational techniques that identify all the likely targets for a given chemical compound, also termed as the problem of Target Fishing, has been an active area of research. Identification of likely targets of a chemical compound helps to understand problems such as toxicity, lack of efficacy in humans, and poor physical properties associated with that compound in the early stages of drug discovery. In this paper we present a set of techniques whose goal is to rank or prioritize targets in the context of a given chemical compound such that most targets that this compound may show activity against appear higher in the ranked list. These methods are based on our extensions to the SVM and Ranking Perceptron algorithms for this problem. Our extensive experimental study shows that the methods developed in this work outperform previous approaches by 2% to 60% under different evaluation criterions. PMID:19764745

  9. Prediction of carcinogenicity for diverse chemicals based on substructure grouping and SVM modeling.

    PubMed

    Tanabe, Kazutoshi; Lučić, Bono; Amić, Dragan; Kurita, Takio; Kaihara, Mikio; Onodera, Natsuo; Suzuki, Takahiro

    2010-11-01

    The Carcinogenicity Reliability Database (CRDB) was constructed by collecting experimental carcinogenicity data on about 1,500 chemicals from six sources, including IARC, and NTP databases, and then by ranking their reliabilities into six unified categories. A wide variety of 911 organic chemicals were selected from the database for QSAR modeling, and 1,504 kinds of different molecular descriptors were calculated, based on their 3D molecular structures as modeled by the Dragon software. Positive (carcinogenic) and negative (non-carcinogenic) chemicals containing various substructures were counted using atom and functional group count descriptors, and the statistical significance of ratios of positives to negatives was tested for those substructures. Very few were judged to be strongly related to carcinogenicity, among substructures known to be responsible for carcinogens as revealed from biomedical studies. In order to develop QSAR models for the prediction of the carcinogenicities of a wide variety of chemicals with a satisfactory performance level, the relationship between the carcinogenicity data with improved reliability and a subset of significant descriptors selected from 1,504 Dragon descriptors was analyzed with a support vector machine (SVM) method: the classification function (SVC) for weighted data in LIBSVM program was used to classify chemicals into two carcinogenic categories (positive or negative), where weights were set depending on the reliabilities of the carcinogenicity data. The quality and stability of the models presented were tested by performing a dual cross-validation procedure. A single SVM model as the first step was developed for all the 911 chemicals using 250 selected descriptors, achieving an overall accuracy level, i.e., positive and negative correct estimate, of about 70%. In order to improve the accuracy of the final model, the 911 chemicals were classified into 20 mutually overlapping subgroups according to contained substructures

  10. Mammalian models of chemically induced primary malignancies exploitable for imaging-based preclinical theragnostic research

    PubMed Central

    Liu, Yewei; Yin, Ting; Feng, Yuanbo; Cona, Marlein Miranda; Huang, Gang; Liu, Jianjun; Song, Shaoli; Jiang, Yansheng; Xia, Qian; Swinnen, Johannes V.; Bormans, Guy; Himmelreich, Uwe; Oyen, Raymond

    2015-01-01

    Compared with transplanted tumor models or genetically engineered cancer models, chemically induced primary malignancies in experimental animals can mimic the clinical cancer progress from the early stage on. Cancer caused by chemical carcinogens generally develops through three phases namely initiation, promotion and progression. Based on different mechanisms, chemical carcinogens can be divided into genotoxic and non-genotoxic ones, or complete and incomplete ones, usually with an organ-specific property. Chemical carcinogens can be classified upon their origins such as environmental pollutants, cooked meat derived carcinogens, N-nitroso compounds, food additives, antineoplastic agents, naturally occurring substances and synthetic carcinogens, etc. Carcinogen-induced models of primary cancers can be used to evaluate the diagnostic/therapeutic effects of candidate drugs, investigate the biological influential factors, explore preventive measures for carcinogenicity, and better understand molecular mechanisms involved in tumor initiation, promotion and progression. Among commonly adopted cancer models, chemically induced primary malignancies in mammals have several advantages including the easy procedures, fruitful tumor generation and high analogy to clinical human primary cancers. However, in addition to the time-consuming process, the major drawback of chemical carcinogenesis for translational research is the difficulty in noninvasive tumor burden assessment in small animals. Like human cancers, tumors occur unpredictably also among animals in terms of timing, location and the number of lesions. Thanks to the availability of magnetic resonance imaging (MRI) with various advantages such as ionizing-free scanning, superb soft tissue contrast, multi-parametric information, and utility of diverse contrast agents, now a workable solution to this bottleneck problem is to apply MRI for noninvasive detection, diagnosis and therapeutic monitoring on those otherwise

  11. Atmospheric chemical transport based on high-resolution model-derived winds: A case study

    NASA Astrophysics Data System (ADS)

    Hannan, John R.; Fuelberg, Henry E.; Thompson, Anne M.; Bieberbach, George; Knabb, Richard D.; Kondo, Yutaka; Anderson, Bruce E.; Browell, Edward V.; Gregory, Gerald L.; Sachse, Glen W.; Singh, Hanwant B.

    2000-02-01

    Flight 10 of NASA's Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (SONEX) extended southwest of Lajes, Azores. A variety of chemical signatures was encountered. These signatures are examined in detail, relating them to meteorological data from a high-resolution numerical model having a horizontal grid spacing of 30 and 90 km with 26 vertical levels. The meteorological output at hourly intervals is used to create backward trajectories from the locations of the chemical signatures. Four major categories of chemical signatures are discussed: stratospheric, lightning, continental pollution, and a mixed chemical layer. The strong stratospheric signal is encountered just south of the Azores in a region of depressed tropopause height. Three chemical signatures at different altitudes in the upper troposphere are attributed to lightning. Backward trajectories from these signatures extend to locations of cloud-to-ground lightning. Specifically, results show that the trajectories pass over regions of lightning 1-2 days earlier over the eastern Gulf of Mexico and off the southeast coast of the United States. The lowest leg of the flight exhibits a chemical signature consistent with continental pollution. Trajectories from this signature are found to pass over the highly populated Northeast Corridor of the United States. Surface-based pollution apparently is lofted to the altitudes of the trajectories by convective clouds along the East Coast that did not contain lightning. Finally, a mixed layer is described. Its chemical signature is intermediate to those of lightning and continental pollution. Backward trajectories from this layer pass between the trajectories of the lightning and pollution signatures. Thus they likely are impacted by both sources.

  12. Analysis of Plug Load Capacities and Power Requirements in Commercial Buildings: Preprint

    SciTech Connect

    Sheppy, M.; Torcellini, P.; Gentile-Polese, L.

    2014-08-01

    Plug and process load power requirements are frequently overestimated because designers often use estimates based on 'nameplate' data, or design assumptions are high because information is not available. This generally results in oversized heating, ventilation, and air-conditioning systems; increased initial construction costs; and increased energy use caused by inefficiencies at low, part-load operation. Rightsizing of chillers in two buildings reduced whole-building energy use by 3%-4%. If an integrated design approach could enable 3% whole-building energy savings in all U.S. office buildings stock, it could save 34 TBtu of site energy per year.

  13. Room temperature continuous wave operation of quantum cascade lasers with 12.5% wall plug efficiency

    SciTech Connect

    Bai, Y.; Slivken, S.; Darvish, S. R.; Razeghi, M.

    2008-07-14

    An InP based quantum cascade laser heterostructure emitting at 4.6 {mu}m was grown with gas-source molecular beam epitaxy. The wafer was processed into a conventional double-channel ridge waveguide geometry with ridge widths of 19.7 and 10.6 {mu}m without semi-insulating InP regrowth. An uncoated, narrow ridge device with a 4.8 mm cavity length was epilayer down bonded to a diamond submount and exhibits 2.5 W maximum output power with a wall plug efficiency of 12.5% at room temperature in continuous wave operation.

  14. Effectiveness of instruction based on the constructivist approach on understanding chemical equilibrium concepts

    NASA Astrophysics Data System (ADS)

    Akkuş Hüseyin; Kadayifçi, Hakki; Atasoy, Basri; Geban, Ömer

    2003-02-01

    The purpose of this study was to identify misconceptions concerning chemical equilibrium concepts and to investigate the effectiveness of instruction based on the constructivist approach over traditional instruction on 10th grade students' understanding of chemical equilibrium concepts. The subjects of this study consisted of 71 10th grade students from two chemistry classes of the same teacher. Each teaching strategy was randomly assigned to one class. The data were obtained from 32 students in the experimental group taught with instruction informed by the constructivist approach and 39 students in the control group taught with traditional instruction. The data were analysed using analysis of covariance. The results indicated that the students who used the constructivist principles-oriented instruction earned significantly higher scores than those taught by traditional instruction in terms of achievement related to chemical equilibrium concepts. In addition, students' previous learning and science process skills each made a significant contribution to the achievement related to chemical equilibrium concepts. In light of the findings obtained from the results, an additional misconception of chemical equilibrium concepts was determined in addition to the misconceptions in related literature. This misconception is that when one of the reactants is added to the equilibrium system, the concentration of the substance that was added will decrease below its value at the initial equilibrium.

  15. High-resolution X-ray computed tomography scanning of primate copulatory plugs.

    PubMed

    Parga, Joyce A; Maga, Murat; Overdorff, Deborah J

    2006-04-01

    In this study, high-resolution computed tomography X-ray scanning was used to scan ring-tailed lemur (Lemur catta) copulatory plugs. This method produced accurate measures of plug volume and surface area, but was not useful for visualizing plug internal structure. Copulatory plug size was of interest because it may relate to male fertilization success. Copulatory plugs form from coagulated ejaculate, and are routinely displaced in this species by the penis of a subsequent mate during copulation (Parga [2003] Int. J. Primatol. 24:889-899). Because one potential function of these plugs may be to preclude or delay other males' successful insemination of females, we tested the hypothesis that larger plugs are more difficult for subsequent males to displace. Plugs were collected opportunistically upon displacement during data collection on L. catta mating behavior on St. Catherines Island, Georgia (USA) during two subsequent breeding seasons. Copulatory plugs exhibited a wide range of volumes: 1,758-5,013.6 mm3 (n = 9). Intraindividual differences in plug volume were sometimes greater than interindividual differences. Contrary to predictions, larger plugs were not more time-consuming for males to displace via penile intromission during copulation. Nor were plugs with longer vaginal residence times notably smaller than plugs with shorter residence times, as might be expected if plugs disintegrate while releasing sperm (Asdell [1946] Patterns of Mammalian Reproduction; Ithaca: Comstock). We found a significant inverse correlation between number of copulatory mounts leading to ejaculation and copulatory plug volume. This may indicate that if males are sufficiently sexually aroused to reach ejaculation in fewer mounts, they tend to produce ejaculates of greater volume. PMID:16345065

  16. Chemical analysis of bleach and hydroxide-based solutions after decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX).

    PubMed

    Hopkins, F B; Gravett, M R; Self, A J; Wang, M; Chua, Hoe-Chee; Hoe-Chee, C; Lee, H S Nancy; Sim, N Lee Hoi; Jones, J T A; Timperley, C M; Riches, J R

    2014-08-01

    Detailed chemical analysis of solutions used to decontaminate chemical warfare agents can be used to support verification and forensic attribution. Decontamination solutions are amongst the most difficult matrices for chemical analysis because of their corrosive and potentially emulsion-based nature. Consequently, there are relatively few publications that report their detailed chemical analysis. This paper describes the application of modern analytical techniques to the analysis of decontamination solutions following decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX). We confirm the formation of N,N-diisopropylformamide and N,N-diisopropylamine following decontamination of VX with hypochlorite-based solution, whereas they were not detected in extracts of hydroxide-based decontamination solutions by nuclear magnetic resonance (NMR) spectroscopy or gas chromatography-mass spectrometry. We report the electron ionisation and chemical ionisation mass spectroscopic details, retention indices, and NMR spectra of N,N-diisopropylformamide and N,N-diisopropylamine, as well as analytical methods suitable for their analysis and identification in solvent extracts and decontamination residues.

  17. Structurally Integrated Photoluminescent Chemical and Biological Sensors: An Organic Light-Emitting Diode-Based Platform

    NASA Astrophysics Data System (ADS)

    Shinar, J.; Shinar, R.

    The chapter describes the development, advantages, challenges, and potential of an emerging, compact photoluminescence-based sensing platform for chemical and biological analytes, including multiple analytes. In this platform, the excitation source is an array of organic light-emitting device (OLED) pixels that is structurally integrated with the sensing component. Steps towards advanced integration with additionally a thin-film-based photodetector are also described. The performance of the OLED-based sensing platform is examined for gas-phase and dissolved oxygen, glucose, lactate, ethanol, hydrazine, and anthrax lethal factor.

  18. Development and laboratory evaluation of chemically-based baited ovitrap for the monitoring of Aedes aegypti.

    PubMed

    Baak-Baak, Carlos M; Rodríguez-Ramírez, Américo D; García-Rejón, Julián E; Ríos-Delgado, Silvany; Torres-Estrada, José L

    2013-06-01

    Aedes (Stegomyia) aegypti is considered to be the most important dengue vector worldwide. Studies were conducted to design and evaluate a chemically-based baited ovitrap for monitoring Ae. aegypti under laboratory conditions. Several known chemical attractants and three types of ovitraps (ovitraps A, B, and C) were evaluated throughout the oviposition bioassays. Oviposition responses of gravid female Ae. aegypti were evaluated to n-heneicosane, 3-methylindole (skatole), 4-methylphenol (p-cresol), and phenol. Female Ae. aegypti were attracted to all the evaluated compounds. Among them, n-heneicosane at a concentration of 10 ppm (mg/l), skatole from 50 to 1000 ppm, p-cresol at 100 ppm, and phenol at 50 ppm showed a significant positive oviposition response. A blend of the four chemical attractants increased the oviposition response; 67% of the eggs were deposited in the treatment compared to the control. Female Ae. aegypti were significantly more attracted to ovitrap A loaded with the four-component synthetic blend compared to the standard ovitrap in the oviposition bioassays. The compound used in ovitrap A retained its attractant property for up to three days. The chemically-based baited ovitrap may be considered as an option to be integrated during the monitoring of dengue virus vectors in México. PMID:23701623

  19. Ultrasensitive standoff chemical sensing based on nonlinear multi-photon laser wave-mixing spectroscopy

    NASA Astrophysics Data System (ADS)

    Gregerson, Marc; Hetu, Marcel; Iwabuchi, Manna; Jimenez, Jorge; Warren, Ashley; Tong, William G.

    2012-10-01

    Nonlinear multi-photon laser wave mixing is presented as an ultrasensitive optical detection method for chem/bio agents in thin films and gas- and liquid-phase samples. Laser wave mixing is an unusually sensitive optical absorption-based detection method that offers significant inherent advantages including excellent sensitivity, small sample requirements, short optical path lengths, high spatial resolution, high spectral resolution and standoff remote detection capability. Wave mixing can detect trace amounts of chemicals even when using micrometer-thin samples, and hence, it can be conveniently interfaced to fibers, microarrays, microfluidic systems, lab-on-a-chip, capillary electrophoresis and other capillary- or fiber-based chemical separation systems. The wave-mixing signal is generated instantaneously as the two input laser beams intersect inside the analyte of interest. Laser excitation wavelengths can be tuned to detect multiple chemicals in their native form since wave mixing can detect both fluorescing and non-fluorescing samples at parts-pertrillion or better detection sensitivity levels. The wave-mixing signal is a laser-like coherent beam, and hence, it allows reliable and effective remote sensing of chemicals. Sensitive wave-mixing detectors offer many potential applications including sensitive detection of biomarkers, early detection of diseases, sensitive monitoring of environmental samples, and reliable detection of hazardous chem/bio agents with a standoff detection capability.

  20. Chemical entity recognition in patents by combining dictionary-based and statistical approaches.

    PubMed

    Akhondi, Saber A; Pons, Ewoud; Afzal, Zubair; van Haagen, Herman; Becker, Benedikt F H; Hettne, Kristina M; van Mulligen, Erik M; Kors, Jan A

    2016-01-01

    We describe the development of a chemical entity recognition system and its application in the CHEMDNER-patent track of BioCreative 2015. This community challenge includes a Chemical Entity Mention in Patents (CEMP) recognition task and a Chemical Passage Detection (CPD) classification task. We addressed both tasks by an ensemble system that combines a dictionary-based approach with a statistical one. For this purpose the performance of several lexical resources was assessed using Peregrine, our open-source indexing engine. We combined our dictionary-based results on the patent corpus with the results of tmChem, a chemical recognizer using a conditional random field classifier. To improve the performance of tmChem, we utilized three additional features, viz. part-of-speech tags, lemmas and word-vector clusters. When evaluated on the training data, our final system obtained an F-score of 85.21% for the CEMP task, and an accuracy of 91.53% for the CPD task. On the test set, the best system ranked sixth among 21 teams for CEMP with an F-score of 86.82%, and second among nine teams for CPD with an accuracy of 94.23%. The differences in performance between the best ensemble system and the statistical system separately were small.Database URL: http://biosemantics.org/chemdner-patents. PMID:27141091