WorldWideScience

Sample records for hydrogen environment assisted

  1. Hydrogen-environment-assisted cracking of an aluminum-zinc-magnesium(copper) alloy

    Science.gov (United States)

    Young, George Aloysius, Jr.

    There is strong evidence to indicate that hydrogen embrittlement plays a significant, if not controlling, role in the environmentally assisted cracking of 7XXX series aluminum alloys. In order to better understand hydrogen environment assisted cracking (HEAC), crack growth rate tests in the K-independent stage II crack growth regime were conducted on fracture mechanics specimens of an Al-6.09Zn-2.14Mg-2.19Cu alloy (AA 7050) and a low copper variant (Al-6.87Zn-2.65Mg-0.06Cu). Crack growth rate tests were performed in 90% relative humidity (RH) air between 25 and 90°C to assure hydrogen embrittlement control. The underaged, peak aged, and overaged tempers were investigated. Hydrogen uptake in humid air, hydrogen diffusion, and hydrogen trapping were investigated for each temper. Lastly, near crack tip hydrogen concentration depth profiles were analyzed via nuclear reaction analysis (NRA) and secondary ion mass spectroscopy (SIMS) using a liquid gallium, focused ion beam sputtering source (FIB/SIMS). The results of this study help explain and quantify empirically known trends concerning HEAC resistance and also establish new findings. In the copper bearing alloy, overaged tempers are more resistant but not immune to HEAC. Humid air is an aggressive environment for Al-Zn-Mg alloys because water vapor reacts with bare aluminum to produce high surface concentrations of hydrogen. This occurs in all tempers. Hydrogen diffuses from the near surface region to the high triaxial stress region ahead of the crack tip and collects at the high angle grain boundaries. The combination of tensile stress and high hydrogen concentration at the grain boundaries then causes intergranular fracture. Crack extension bares fresh metal and the process of hydrogen production, uptake, diffusion to the stressed grain boundary, and crack extension repeats. One reason increased degree of aging improves HEAC resistance in copper bearing 7XXX series alloys is that volume lattice and effective

  2. Factors Affecting the Hydrogen Environment Assisted Cracking Resistance of an Al-Zn-Mg-(Cu) Alloy

    Energy Technology Data Exchange (ETDEWEB)

    G.A. Young; J.R. Scully

    2001-09-12

    It is well established that Al-Zn-Mg-(Cu) aluminum alloys are susceptible to hydrogen environment assisted cracking (HEAC) when exposed to aqueous environments. In Al-Zn-Mg-Cu alloys, overaged tempers are commonly used to increase HEAC resistance at the expense of strength. Overaging has little benefit in low copper alloys. However, the mechanism or mechanisms by which overaging imparts HEAC resistance is poorly understood. The present research investigated hydrogen uptake, diffusion, and crack growth rate in 90% relative humidity (RH) air for both a commercial copper bearing Al-Zn-Mg-Cu alloy (AA 7050) and a low copper variant of this alloy in order to better understand the factors which affect HEAC resistance. Experimental methods used to evaluate hydrogen concentrations local to a surface and near a crack tip include nuclear reaction analysis (NRA), focused ion beam, secondary ion mass spectroscopy (FIB/SIMS) and thermal desorption spectroscopy (TDS). When freshly bared coupons of AA 7050 are exposed to 90 C, 90% RH air, hydrogen ingress follows inverse-logarithmic-type kinetics and is equivalent for underaged (HEAC susceptible) and overaged (HEAC resistant) tempers. However, when the native oxide is allowed to form (24 hrs in 25 C, 40% RH lab air) prior to exposure to 90 C, 90% RH air, underaged alloy shows significantly greater hydrogen ingress than the overaged alloy. Humid air is a very aggressive environment producing local ({approx}1{micro}m) hydrogen concentrations in excess of 10,000 wt. ppm at 90 C. In the copper bearing alloy, overaging also effects the apparent diffusivity of hydrogen. As AA 7050 is aged from underaged {yields} peak aged {yields} overaged, the activation energy for hydrogen diffusion increases and the apparent diffusivity for hydrogen decreases, In the low copper alloy, overaging has little effect on hydrogen diffusion. Comparison of the apparent activation energies for hydrogen diffusion and for K independent (stage II) crack growth

  3. The Effect of Microstructural Variation on the Hydrogen Environment-Assisted Cracking of Monel K-500

    Science.gov (United States)

    Harris, Zachary D.; Dolph, Justin D.; Pioszak, Greger L.; Rincon Troconis, Brendy C.; Scully, John R.; Burns, James T.

    2016-07-01

    The influence of microstructural variation on hydrogen environment-assisted cracking (HEAC) of Monel K-500 was evaluated using five nominally peak-aged lots of material tested under slow-rising stress intensity loading while immersed in NaCl solution under cathodic polarizations. Minimal variation in HEAC resistance among material lots was observed for an applied potential of -950 mVSCE ( E app, vs saturated calomel), whereas lot-to-lot variability in the fracture morphology demonstrates a significant difference in the HEAC resistance at the less negative potential of -850 mVSCE, suggesting that relatively severe H environments produce sufficient crack-tip H to minimize the impact of metallurgical differences. Sensitivity analyses accomplished by varying the inputs used in decohesion-based, micromechanical models imply significant variations in HEAC resistance are possible for realistic changes in grain boundary toughness, hydrogen uptake behavior, and yield strength. Grain size, impurity segregation (including the effects of gettering elements), grain boundary character/connectivity, and crack path tortuosity are also considered in the context of HEAC susceptibility. Yield strength, global hydrogen content, as well as impurity segregation to grain boundaries, especially boron and sulfur, are speculatively considered to be the dominant contributions in determining HEAC resistance. Modifications that would incorporate the effects of grain boundary segregation are proposed for the K TH model; detailed validation of such changes require high-fidelity and quantitative inputs for the degree of grain boundary segregation. Regardless, fracture mechanics-based HEAC results, detailed microstructural characterization, and micromechanical modeling were successfully coupled to gain insights into the influences governing the microstructure-dependent HEAC susceptibility of Monel K-500.

  4. Measurement and Modeling of Hydrogen Environment-Assisted Cracking in Monel K-500

    Science.gov (United States)

    Gangloff, Richard P.; Ha, Hung M.; Burns, James T.; Scully, John R.

    2014-08-01

    Hydrogen environment-assisted cracking (HEAC) of Monel K-500 is quantified using slow-rising stress intensity loading with electrical potential monitoring of small crack propagation and elastoplastic J-integral analysis. For this loading, with concurrent crack tip plastic strain and H accumulation, aged Monel K-500 is susceptible to intergranular HEAC in NaCl solution when cathodically polarized at -800 mVSCE ( E A, vs saturated calomel) and lower. Intergranular cracking is eliminated by reduced cathodic polarization more positive than -750 mVSCE. Crack tip diffusible H concentration rises, from near 0 wppm at E A of -765 mVSCE, with increasing cathodic polarization. This behavior is quantified by thermal desorption spectroscopy and barnacle cell measurements of hydrogen solubility vs overpotential for planar electrodes, plus measured-local crevice potential, and pH scaled to the crack tip. Using crack tip H concentration, excellent agreement is demonstrated between measurements and decohesion-based model predictions of the E A dependencies of threshold stress intensity and Stage II growth rate. A critical level of cathodic polarization must be exceeded for HEAC to occur in aged Monel K-500. The damaging-cathodic potential regime likely shifts more negative for quasi-static loading or increasing metallurgical resistance to HEAC.

  5. Modeling and experiments to explain the potential dependency of an UHSS to hydrogen environment assisted cracking

    Science.gov (United States)

    Kehler, Beth A.

    Modern ultra high strength steels have been developed with outstanding combinations of strength and fracture toughness but lack intrinsic corrosion resistance. Such steels are used by the military for aircraft components such as landing gears but require coatings and cathodic protection which can lead to various rates of hydrogen production depending on material, geometry, and electro(chemistry). The susceptibility of such steels to internal hydrogen embrittlement (IHE) and hydrogen environment embrittlement (HEE) limits their use in marine environments. The objective of this research is to develop the understanding necessary to design coated ultra high strength steels that resist HEE when stressed in marine environments. The cause of HEE is the establishment of high diffusible hydrogen concentrations (CH,diff) at the crack tip. There is a window of applied potentials (Eapplied) where susceptibility to HEE is reduced because CH,diff is reduced. However, Eapplied itself does not yield insight as to the exact conditions at the crack tip. Ohmic potential drop and electrochemical/chemical reactions in the crack can lead to a significantly different environment at the crack tip than on the surface. The issues that hinder understanding of HEE center on the capability to quantify and ultimately predict crack tip hydrogen concentrations (C H,Tip) relative to critical concentrations that trigger fracture as a function of Eapplied. CH,tip was characterized using a multi-pronged approach. Scaling laws were developed to enable measurements of E and pH in a scaled-up crack as a function of the scaling parameter, x2/G and Eapplied . Such measurements were correlated with CH,diff using an experimentally determined hydrogen uptake law based on first order absorption laws and trapping theory. CH,diff values were then used as inputs into existing micromechanical models for KTH and da/dtII to predict cracking susceptibility. The scientific contributions of this work include the

  6. Strain gradient plasticity-based modeling of hydrogen environment assisted cracking

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; Niordson, Christian Frithiof; P. Gangloff, Richard

    2016-01-01

    Finite element analysis of stress about a blunt crack tip, emphasizing finite strain and phenomenologicaland mechanism-based strain gradient plasticity (SGP) formulations, is integrated with electrochemical assessment of occluded-crack tip hydrogen (H) solubility and two H-decohesion models......; it is imperative to account for SGP in H cracking models. Predictions of the threshold stress intensity factor and H-diffusion limited Stage II crack growth rate agree with experimental data for a high strength austenitic Ni-Cusuperalloy (Monel®K-500) and two modern ultra-high strength martensitic steels (Aer...

  7. Mechanism-Based Modeling of Hydrogen Environment Assisted Cracking (HEAC) in High Strength Alloys for Marine Applications: Prediction of Monel K-500 HEAC for Select Environmental and Mechanical Conditions

    Science.gov (United States)

    2012-10-15

    activation energies (-40 kJ/mol). Moreover, possible trapping sites will differ for precipitation hardened fee Ni-based alloys compared to ferrous ...FINAL REPORT Mechanism-Based Modeling of Hydrogen Environment Assisted Cracking (HEAC) in High Strength Alloys for Marine Applications: Prediction...the microscopic scale to enable threshold and crack growth rate predictions in Ni-based alloys which differ substantially from high strength steels

  8. Hydrogen bonding in tight environments

    DEFF Research Database (Denmark)

    Pirrotta, Alessandro; Solomon, Gemma C.; Franco, Ignacio

    2016-01-01

    The single-molecule force spectroscopy of a prototypical class of hydrogen-bonded complexes is computationally investigated. The complexes consist of derivatives of a barbituric acid and a Hamilton receptor that can form up to six simultaneous hydrogen bonds. The force-extension (F-L) isotherms...... of the host-guest complexes are simulated using classical molecular dynamics and the MM3 force field, for which a refined set of hydrogen bond parameters was developed from MP2 ab initio computations. The F-L curves exhibit peaks that signal conformational changes during elongation, the most prominent...... of which is in the 60-180 pN range and corresponds to the force required to break the hydrogen bonds. These peaks in the F-L curves are shown to be sensitive to relatively small changes in the chemical structure of the host molecule. Thermodynamic insights into the supramolecular assembly were obtained...

  9. Environment-assisted precision measurement

    DEFF Research Database (Denmark)

    Goldstein, G.; Cappellaro, P.; Maze, J. R.

    2011-01-01

    We describe a method to enhance the sensitivity of precision measurements that takes advantage of the environment of a quantum sensor to amplify the response of the sensor to weak external perturbations. An individual qubit is used to sense the dynamics of surrounding ancillary qubits, which are ...

  10. Hydrogen-Assisted IC Engine Combustion as a Route to Hydrogen Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Andre Boehman; Daniel Haworth

    2008-09-30

    The 'Freedom Car' Initiative announced by the Bush Administration has placed a significant emphasis on development of a hydrogen economy in the United States. While the hydrogen-fueled fuel-cell vehicle that is the focus of the 'Freedom Car' program would rely on electrochemical energy conversion, and despite the large amount of resources being devoted to its objectives, near-term implementation of hydrogen in the transportation sector is not likely to arise from fuel cell cars. Instead, fuel blending and ''hydrogen-assisted'' combustion are more realizable pathways for wide-scale hydrogen utilization within the next ten years. Thus, a large potential avenue for utilization of hydrogen in transportation applications is through blending with natural gas, since there is an existing market for natural-gas vehicles of various classes, and since hydrogen can provide a means of achieving even stricter emissions standards. Another potential avenue is through use of hydrogen to 'assist' diesel combustion to permit alternate combustion strategies that can achieve lower emissions and higher efficiency. This project focused on developing the underlying fundamental information to support technologies that will facilitate the introduction of coal-derived hydrogen into the market. Two paths were envisioned for hydrogen utilization in transportation applications. One is for hydrogen to be mixed with other fuels, specifically natural gas, to enhance performance in existing natural gas-fueled vehicles (e.g., transit buses) and provide a practical and marketable avenue to begin using hydrogen in the field. A second is to use hydrogen to enable alternative combustion modes in existing diesel engines, such as homogeneous charge compression ignition, to permit enhanced efficiency and reduced emissions. Thus, this project on hydrogen-assisted combustion encompassed two major objectives: (1) Optimization of hydrogen-natural gas mixture

  11. Blended Learning in Personalized Assistive Learning Environments

    Science.gov (United States)

    Marinagi, Catherine; Skourlas, Christos

    2013-01-01

    In this paper, the special needs/requirements of disabled students and cost-benefits for applying blended learning in Personalized Educational Learning Environments (PELE) in Higher Education are studied. The authors describe how blended learning can form an attractive and helpful framework for assisting Deaf and Hard-of-Hearing (D-HH) students to…

  12. Titanium corrosion in alkaline hydrogen peroxide environments

    Science.gov (United States)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  13. Simulation of hydrogen and hydrogen-assisted propane ignition in Pt catalyzed microchannel

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, Vikram; Kaisare, Niket S. [Department of Chemical Engineering, Indian Institute of Technology - Madras, Chennai 600 036 (India)

    2010-11-15

    This paper deals with self-ignition of catalytic microburners from ambient cold-start conditions. First, reaction kinetics for hydrogen combustion is validated with experimental results from the literature, followed by validation of a simplified pseudo-2D microburner model. The model is then used to study the self-ignition behavior of lean hydrogen/air mixtures in a Platinum-catalyzed microburner. Hydrogen combustion on Pt is a very fast reaction. During cold start ignition, hydrogen conversion reaches 100% within the first few seconds and the reactor dynamics are governed by the ''thermal inertia'' of the microburner wall structure. The self-ignition property of hydrogen can be used to provide the energy required for propane ignition. Two different modes of hydrogen-assisted propane ignition are considered: co-feed mode, where the microburner inlet consists of premixed hydrogen/propane/air mixtures; and sequential feed mode, where the inlet feed is switched from hydrogen/air to propane/air mixtures after the microburner reaches propane ignition temperature. We show that hydrogen-assisted ignition is equivalent to selectively preheating the inlet section of the microburner. The time to reach steady state is lower at higher equivalence ratio, lower wall thermal conductivity, and higher inlet velocity for both the ignition modes. The ignition times and propane emissions are compared. Although the sequential feed mode requires slightly higher amount of hydrogen, the propane emissions are at least an order of magnitude lower than the other ignition modes. (author)

  14. Recent developments in computer assisted rehabilitation environments

    Institute of Scientific and Technical Information of China (English)

    Rob van der Meer

    2014-01-01

    Computer Assisted Rehabilitation Environment (CAREN) is a system that integrates a training platform (motion base), a virtual environment, a sensor system (motion capture) and D-flow software. It is useful for both diagnostic and therapeutic use. The human gait pattern can be impaired due to disease, trauma or natural decline. Gait analysis is a useful tool to identify impaired gait patterns. Traditional gait analysis is a very time consuming process and therefore only used in exceptional cases. With new systems a quick and extensive analysis is possible and provides useful tools for therapeutic purposes. The range of systems will be described in this paper, highlighting both their diagnostic use and the therapeutic possibilities. Because wounded warriors often have an impaired gait due to amputations or other extremity trauma, these systems are very useful for military rehabilitative efforts. Additionally, the virtual reality environment creates a very challenging situation for the patient, enhancing their rehabilitation experience. For that reason several Armed Forces have these systems already in use. The most recent experiences will be discussed; including new developments both in the extension of the range of systems and the improvement and adaptation of the software. A new and promising development, the use of CAREN in a special application for patients with post-traumatic stress disorder (PTSD), will also be reviewed.

  15. Fatigue test of carbon epoxy composite high pressure hydrogen storage vessel under hydrogen environment

    Institute of Scientific and Technical Information of China (English)

    Chuan-xiang ZHENG; Liang WANG; Rong LI; Zong-xin WEI; Wei-wei ZHOU

    2013-01-01

    A significant temperature raise within hydrogen vehicle cylinder during the fast filling process will be observed,while the strength and fatigue life of the cylinder will dramatically decrease at high temperature.In order to evaluate the strength and fatigue of composite hydrogen storage vessel,a 70-MPa fatigue test system using hydrogen medium was set up.Experimental study on the fatigue of composite hydrogen storage vessels under real hydrogen environment was performed.The experimental results show that the ultimate strength and fatigue life both decreased obviously compared with the values under hydraulic fatigue test.Furthermore,fatigue property,failure behavior,and safe hydrogen charging/discharging working mode of onboard hydrogen storage vessels were obtained through the fatigue tests.

  16. Alloys For Corrosive, Hydrogen-Rich Environments

    Science.gov (United States)

    Mcpherson, William B.; Bhat, Biliyar N.; Chen, Po-Shou; Kuruvilla, A. K.; Panda, Binayak

    1993-01-01

    "NASA-23" denotes class of alloys resisting both embrittlement by hydrogen and corrosion. Weldable and castable and formed by such standard processes as rolling, forging, and wire drawing. Heat-treated to obtain desired combinations of strength and ductility in ranges of 100 to 180 kpsi yield strength, 120 to 200 kpsi ultimate tensile strength, and 10 to 30 percent elongation at break. Used in place of most common aerospace structural alloy, Inconel(R) 718.

  17. Influence of alloying on hydrogen-assisted cracking and diffusible hydrogen content in Cr–Mo steel welds

    Indian Academy of Sciences (India)

    S K Albert; V Ramasubbu; N Parvathavarthini; T P S Gill

    2003-06-01

    Study of hydrogen-assisted cracking and measurement of diffusible hydrogen content in different Cr–Mo steel welds shows that under identical conditions, susceptibility to cracking increased and diffusible hydrogen content decrease with increase in alloy content. Hydrogen permeation studies show that hydrogen diffusivity decreases and solubility increases with increase in alloy content. Thus decrease in diffusible hydrogen content with increase in alloying is attributed to increase in apparent solubility and decrease in apparent diffusivity of hydrogen. Analysis of the results indicates that variation of diffusible hydrogen content and apparent diffusivity of hydrogen with alloy content can be represented as a function of carbon equivalent CE1 originally proposed to predict the hardness in the heat-affected zone of alloy steel welds.

  18. Strength of hydrogen bonds of water depends on local environment.

    Science.gov (United States)

    Huš, Matej; Urbic, Tomaz

    2012-04-14

    In-depth knowledge of water-water potential is important for devising and evaluating simple water models if they are to accurately describe water properties and reflect various solvation phenomena. Water-water potential depends upon inter-molecular distance, relative orientation of water molecules, and also local environment. When placed at a favorable distance in a favorable orientation, water molecules exhibit a particularly strong attractive interaction called hydrogen bond. Although hydrogen bond is very important for its effects on the elements of life, industrial applications, and bulk water properties, there is no scientific consensus on its true nature and origin. Using quantum-mechanical methods, hydrogen bond strength was calculated in different local environments. A simple empirical linear relationship was discovered between maximum hydrogen bond strength and the number of water molecules in the local environment. The local environment effect was shown to be considerable even on the second coordination shell. Additionally, a negative linear correlation was found between maximum hydrogen bond strength and the distance, at which it was observed. These results provide novel insights into the nature of hydrogen bonding.

  19. Dynamic Services for Assisted Living Environments

    OpenAIRE

    2008-01-01

    Software technologies for assisted living systems can be derived from the more mature domain of pervasive computing and the relative emerging ambient intelligence field. We present herein our position about the need for interoperability enablers extending the software service paradigm and for dependability as key elements of assisted living software systems.

  20. Role of multiaxial stress state in the hydrogen-assisted rolling-contact fatigue in bearings for wind turbines

    Directory of Open Access Journals (Sweden)

    J. Toribio

    2015-07-01

    Full Text Available Offshore wind turbines often involve important engineering challenges such as the improvement of hydrogen embrittlement resistance of the turbine bearings. These elements frequently suffer the so-called phenomenon of hydrogen-assisted rolling-contact fatigue (HA-RCF as a consequence of the synergic action of the surrounding harsh environment (the lubricant supplying hydrogen to the material and the cyclic multiaxial stress state caused by in-service mechanical loading. Thus the complex phenomenon could be classified as hydrogen-assisted rolling-contact multiaxial fatigue (HA-RC-MF. This paper analyses, from the mechanical and the chemical points of view, the so-called ball-on-rod test, widely used to evaluate the hydrogen embrittlement susceptibility of turbine bearings. Both the stress-strain states and the steady-state hydrogen concentration distribution are studied, so that a better elucidation can be obtained of the potential fracture places where the hydrogen could be more harmful and, consequently, where the turbine bearings could fail during their life in service.

  1. Metal-Assisted Hydrogen Storage on Pt-Decorated Single-Walled Carbon Nanohorns

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yun [National Institute of Standards and Technology (NIST); Brown, Craig [National Institute of Standards and Technology (NIST); Neumann, Dan [National Institute of Standards and Technology (NIST); Geohegan, David B [ORNL; Puretzky, Alexander A [ORNL; Rouleau, Christopher M [ORNL; Hu, Hui [ORNL; Styers-Barnett, David J [ORNL; Krasnov, Pavel O. [Rice University; Yakobson, Boris I. [Rice University

    2012-01-01

    The catalytic dissociation of hydrogen molecules by metal nanoparticles and spillover of atomic hydrogen onto various supports is a well-established phenomenon in catalysis. However, the mechanisms by which metal catalyst nanoparticles can assist in enhanced hydrogen storage on high-surface area supports are still under debate. Experimental measurements of metal-assisted hydrogen storage have been hampered by inaccurate estimation of atomically stored hydrogen deduced from comparative measurements between metal-decorated and undecorated samples. Here we report a temperature cycling technique combined with inelastic neutron scattering (INS) measurements of quantum rotational transitions of molecular H2 to more accurately quantify adsorbed hydrogen aided by catalytic particles using single samples. Temperature cycling measurements on single-wall carbon nanohorns (SWCNHs) decorated with 2-3 nm Pt nanoparticles showed 0.17 % mass fraction of metal-assisted hydrogen storage (at 0.5 MPa) at room temperature. Temperature cycling of Pt-decorated SWCNHs using a Sievert s apparatus also indicated metal-assisted hydrogen adsorption of 0.08 % mass fraction at 5 MPa at room temperature. No additional metal-assisted hydrogen storage was observed in SWCNH samples without Pt nanoparticles cycled to room temperature, or in Pt-SWCNHs when the temperature was cycled to less than 150K. The possible formation of C-H bonds due to spilled-over atomic hydrogen was also investigated using both INS and density functional theory calculations.

  2. Center for Advanced Energy Studies: Computer Assisted Virtual Environment (CAVE)

    Data.gov (United States)

    Federal Laboratory Consortium — The laboratory contains a four-walled 3D computer assisted virtual environment - or CAVE TM — that allows scientists and engineers to literally walk into their data...

  3. HYDROGEN-ASSISTED FRACTURE IN FORGED TYPE 304L AUSTENITIC STAINLESS STEEL

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R. [University of Missouri-Kansas City; Bergen, R. [Precision Metal Products; Balch, D. K. [Sandia Natl Laboratory

    2012-09-06

    Austenitic stainless steels generally have good resistance to hydrogen-assisted fracture; however, structural designs for high-pressure gaseous hydrogen are constrained by the low strength of this class of material. Forging is used to increase the low strength of austenitic stainless steels, thus improving the efficiency of structural designs. Hydrogen-assisted racture, however, depends on microstructural details associated with manufacturing. In this study, hydrogen-assisted fracture of forged type 304L austenitic stainless steel is investigated. Microstructural variation in multi-step forged 304L was achieved by forging at different rates and temperatures, and by process annealing. High internal hydrogen content in forged type 304L austenitic stainless steel is achieved by thermal precharging in gaseous hydrogen and results in as much as 50% reduction of tensile ductility.

  4. Influence of hydrogen environments on crack growth in Inconel 718

    Science.gov (United States)

    Walter, R. J.; Chandler, W. T.

    1978-01-01

    The effect of hydrogen environments on sustained-load and cyclic-load crack growth in Inconel 718 was investigated using fracture-mechanics-type specimens. The sustained-load crack growth was determined to be a function of heat-treatment condition, temperature, and hydrogen pressure. The threshold stress intensity for subcritical crack growth was independent of hydrogen pressure at pressures greater than 21 MN/sq m (3000 psi). The cyclic-load crack growth rate in Inconel 718 at low and moderate stress intensity ranges increased with increasing hydrogen pressure. Decreasing the cyclic frequency from 1.0 to 0.1 Hz considerably increased the cyclic crack growth rate at 0.069 MN/sq m (10 psi) and at 68.9 MN/sq m (10,000 psi) hydrogen pressure. A series of measurements performed between 1.0 and 0.1 Hz showed that the crack growth rate increased as a complex function of the time per cycle.

  5. Numerical analysis of hydrogen-assisted rolling-contact fatigue of wind turbine bearings

    Directory of Open Access Journals (Sweden)

    J. Toribio

    2014-10-01

    Full Text Available Offshore wind parks at locations further from the shore often involve serious difficulties, e.g. the maintenance. The bearings of offshore wind turbines are prone to suffer hydrogen-assisted rolling-contact fatigue (HA-RCF. Three important aspects linked with bearing failures are being extensively researched: (i rolling contact fatigue (RCF, (ii influence of carbide particles on fatigue life, and (iii local microplastic strain accumulation via ratcheting. However, there is no reference related to bearing failure in harsh environment. This way, this paper helps to gain a better understanding of the influence of hydrogen on the service life of offshore wind turbine bearings through a numerical study. So, the widely used RCF ball-on-rod test was simulated by finite element method in order to obtain the stress-strain state inside the bearings during life in service and, from this, to elucidate the potential places where the hydrogen could be more harmful and, therefore, where the bearing material should be improved.

  6. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis.

    Science.gov (United States)

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A; Robertson, Peter K J; Irvine, John T S

    2016-01-28

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels.

  7. Hydrogen Assisted Cracking of High Strength Steel Welds

    Science.gov (United States)

    1988-05-01

    of as-recieved MIL-A-46100 291 500X, Nital etch. 5.4 Microstructure of MIL-A-46100 after heat 292 treament procedure and machining. 50X, Nital etch...gas. (Ref F.5) 1.11 Variation in the diffusible hydrogen content as a 69 function of heat input. (Ref F.5) 1.12 Diffusible hydrogen content of GTA welds...of the square root of hydrogen partial pressure. (Ref C.7) 3.9 Variation in weld current, voltage, and heat 208 input as a function of hydrogen in

  8. Prediction of diffusion assisted hydrogen embrittlement failure in high strength martensitic steels

    Science.gov (United States)

    Wu, Q.; Zikry, M. A.

    2015-12-01

    A stress assisted hydrogen diffusion transport model, a dislocation-density-based multiple-slip crystalline plasticity formulation, and an overlapping fracture method were used to investigate hydrogen diffusion and embrittlement in lath martensitic steels with distributions of M23C6 carbide precipitates. The formulation accounts for variant morphologies based on orientation relationships (ORs) that are uniquely inherent to lath martensitic microstructures. The interrelated effects of martensitic block and packet boundaries and carbide precipitates on hydrogen diffusion, hydrogen assisted crack nucleation and growth, are analyzed to characterize the competition between cleavage fracture and hydrogen diffusion assisted fracture along preferential microstructural fracture planes. Stresses along the three cleavage planes and the six hydrogen embrittlement fracture planes are monitored, such that crack nucleation and growth can nucleate along energetically favorable planes. High pressure gradients result in the accumulation of hydrogen, which embrittles martensite, and results in crack nucleation and growth along {110} planes. Cleavage fracture occurs along {100} planes when there is no significant hydrogen diffusion. The predictions indicate that hydrogen diffusion can suppress the emission and accumulation of dislocation density, and lead to fracture with low plastic strains.

  9. The food environment of students on a financial assistance ...

    African Journals Online (AJOL)

    Open Access article distributed under the terms of the ... Keywords: financial assistance, food environment, university students ... Secondly, all food and drink available at the six food outlets were ... changes, including increased alcohol consumption, irregular ... been linked with over-nutrition due to the low cost of energy.

  10. Application requirements for Robotic Nursing Assistants in hospital environments

    Science.gov (United States)

    Cremer, Sven; Doelling, Kris; Lundberg, Cody L.; McNair, Mike; Shin, Jeongsik; Popa, Dan

    2016-05-01

    In this paper we report on analysis toward identifying design requirements for an Adaptive Robotic Nursing Assistant (ARNA). Specifically, the paper focuses on application requirements for ARNA, envisioned as a mobile assistive robot that can navigate hospital environments to perform chores in roles such as patient sitter and patient walker. The role of a sitter is primarily related to patient observation from a distance, and fetching objects at the patient's request, while a walker provides physical assistance for ambulation and rehabilitation. The robot will be expected to not only understand nurse and patient intent but also close the decision loop by automating several routine tasks. As a result, the robot will be equipped with sensors such as distributed pressure sensitive skins, 3D range sensors, and so on. Modular sensor and actuator hardware configured in the form of several multi-degree-of-freedom manipulators, and a mobile base are expected to be deployed in reconfigurable platforms for physical assistance tasks. Furthermore, adaptive human-machine interfaces are expected to play a key role, as they directly impact the ability of robots to assist nurses in a dynamic and unstructured environment. This paper discusses required tasks for the ARNA robot, as well as sensors and software infrastructure to carry out those tasks in the aspects of technical resource availability, gaps, and needed experimental studies.

  11. A ’Hydrogen Partitioning’ Model for Hydrogen Assisted Crack Growth.

    Science.gov (United States)

    1984-09-01

    ABSTRACT’ (Centfaue en revere aide it MWueaein ~VIdantiv by hioc ehm ~m) A "hydrogen partitioning"’ model has been developed to account for the pressure and...boundaries are strong trapping sites for hydrogen [19-21]. The equilibrium partitioning of hydrogen between the grain boundaries and the lattice can...has been estimated to be 73 k/mol, which satisfies the requirement of binding enthalpy for strong traps. (iii) The pressure dependence of T is

  12. Environment-assisted quantum transport in ordered systems

    CERN Document Server

    Kassal, Ivan

    2012-01-01

    Noise-assisted transport in quantum systems occurs when quantum time-evolution and decoherence conspire to produce a transport efficiency that is higher than what would be seen in either the purely quantum or purely classical cases. It has been understood as the suppression of coherent quantum localization through noise, which brings detuned quantum levels into resonance and thus facilitates transport. We report several new mechanisms of environment-assisted transport in ordered systems, in which there is no localization to be overcome.

  13. 3-D FINITE ELEMENT ANALYSIS OF THE EFFECT OF WELDING RESIDUAL STRESS ON HYDROGEN DIFFUSION IN HYDROGEN CONTAINED ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The hydrogen distribution of 16MnR steel weldment in hydrogen contained environment was calculated using the finite element method (FEM). The effect of welding residual stress on hydrogen diffusion has been discussed using a 3-D sequential coupling finite element analysis procedure complied by Abaqus code. The hydrogen diffusion coefficient in weld metal, the heat affected zone (HAZ), and the base metal of the 16MnR steel weldment were measured using the electrochemical permeation technique. The hydrogen diffusion without the effect of stress was also calculated and compared. Owing to the existence of welding residual stress, the hydrogen concentration was obviously increased and the hydrogen would diffuse and accumulate in the higher stress region.

  14. Human-inspired sound environment recognition system for assistive vehicles

    Science.gov (United States)

    González Vidal, Eduardo; Fredes Zarricueta, Ernesto; Auat Cheein, Fernando

    2015-02-01

    Objective. The human auditory system acquires environmental information under sound stimuli faster than visual or touch systems, which in turn, allows for faster human responses to such stimuli. It also complements senses such as sight, where direct line-of-view is necessary to identify objects, in the environment recognition process. This work focuses on implementing human reaction to sound stimuli and environment recognition on assistive robotic devices, such as robotic wheelchairs or robotized cars. These vehicles need environment information to ensure safe navigation. Approach. In the field of environment recognition, range sensors (such as LiDAR and ultrasonic systems) and artificial vision devices are widely used; however, these sensors depend on environment constraints (such as lighting variability or color of objects), and sound can provide important information for the characterization of an environment. In this work, we propose a sound-based approach to enhance the environment recognition process, mainly for cases that compromise human integrity, according to the International Classification of Functioning (ICF). Our proposal is based on a neural network implementation that is able to classify up to 15 different environments, each selected according to the ICF considerations on environment factors in the community-based physical activities of people with disabilities. Main results. The accuracy rates in environment classification ranges from 84% to 93%. This classification is later used to constrain assistive vehicle navigation in order to protect the user during daily activities. This work also includes real-time outdoor experimentation (performed on an assistive vehicle) by seven volunteers with different disabilities (but without cognitive impairment and experienced in the use of wheelchairs), statistical validation, comparison with previously published work, and a discussion section where the pros and cons of our system are evaluated. Significance

  15. Human-inspired sound environment recognition system for assistive vehicles.

    Science.gov (United States)

    Vidal, Eduardo González; Zarricueta, Ernesto Fredes; Cheein, Fernando Auat

    2015-02-01

    The human auditory system acquires environmental information under sound stimuli faster than visual or touch systems, which in turn, allows for faster human responses to such stimuli. It also complements senses such as sight, where direct line-of-view is necessary to identify objects, in the environment recognition process. This work focuses on implementing human reaction to sound stimuli and environment recognition on assistive robotic devices, such as robotic wheelchairs or robotized cars. These vehicles need environment information to ensure safe navigation. In the field of environment recognition, range sensors (such as LiDAR and ultrasonic systems) and artificial vision devices are widely used; however, these sensors depend on environment constraints (such as lighting variability or color of objects), and sound can provide important information for the characterization of an environment. In this work, we propose a sound-based approach to enhance the environment recognition process, mainly for cases that compromise human integrity, according to the International Classification of Functioning (ICF). Our proposal is based on a neural network implementation that is able to classify up to 15 different environments, each selected according to the ICF considerations on environment factors in the community-based physical activities of people with disabilities. The accuracy rates in environment classification ranges from 84% to 93%. This classification is later used to constrain assistive vehicle navigation in order to protect the user during daily activities. This work also includes real-time outdoor experimentation (performed on an assistive vehicle) by seven volunteers with different disabilities (but without cognitive impairment and experienced in the use of wheelchairs), statistical validation, comparison with previously published work, and a discussion section where the pros and cons of our system are evaluated. The proposed sound-based system is very efficient

  16. Study on hydrogen assisted cracking susceptibility of HSLA steel by implant test

    Institute of Scientific and Technical Information of China (English)

    Gopa CHAKRABORTY; R. REJEESH; S.K. ALBERT

    2016-01-01

    DMR-249A is an indigenously developed high strength low alloy steel for Indian ship building industry for making ship-hull and is extensively used in the construction of war ships and submarines. Welding electrodes conforming to SFA 5.5 AWS E8018 C1 has been indigenously developed for welding of this steel using shielded metal arc welding process. In the present study, susceptibility to hydrogen assisted cracking of DMR-249A steel welds made using this electrode has been assessed using implant test. Implant tests were conducted using this electrode at two different levels of diffusible hydrogen, measured using gas chromatography technique. It is observed that both the steel and the welding consumable are not susceptible to hydrogen assisted cracking even with a high diffusible hydrogen level of 9 mL/100g of weld metal. In implant tests, specimen did not fracture even after loading to stress levels higher than the yield strength of the base metal. The good resistance of this steel and the welding consumable, even with high levels of diffusible hydrogen, is attributed to absence of a susceptible microstructure in both the weld metal and heat affected zone. Hence, this study shows that, in the absence of a susceptible microstructure, hydrogen assisted cracking is unlikely to occur even if hydrogen level is high. It also confirms that in welding of DMR-249A with indigenously developed E8018 C1 electrode, hydrogen assisted cracking is not a concern and no preheating is required to avoid it during welding.

  17. Study on hydrogen assisted cracking susceptibility of HSLA steel by implant test

    Directory of Open Access Journals (Sweden)

    Gopa Chakraborty

    2016-12-01

    Full Text Available DMR-249A is an indigenously developed high strength low alloy steel for Indian ship building industry for making ship-hull and is extensively used in the construction of war ships and submarines. Welding electrodes conforming to SFA 5.5 AWS E8018 C1 has been indigenously developed for welding of this steel using shielded metal arc welding process. In the present study, susceptibility to hydrogen assisted cracking of DMR-249A steel welds made using this electrode has been assessed using implant test. Implant tests were conducted using this electrode at two different levels of diffusible hydrogen, measured using gas chromatography technique. It is observed that both the steel and the welding consumable are not susceptible to hydrogen assisted cracking even with a high diffusible hydrogen level of 9 mL/100g of weld metal. In implant tests, specimen did not fracture even after loading to stress levels higher than the yield strength of the base metal. The good resistance of this steel and the welding consumable, even with high levels of diffusible hydrogen, is attributed to absence of a susceptible microstructure in both the weld metal and heat affected zone. Hence, this study shows that, in the absence of a susceptible microstructure, hydrogen assisted cracking is unlikely to occur even if hydrogen level is high. It also confirms that in welding of DMR-249A with indigenously developed E8018 C1 electrode, hydrogen assisted cracking is not a concern and no preheating is required to avoid it during welding.

  18. On environment-assisted capacities of quantum channels

    CERN Document Server

    Winter, A

    2005-01-01

    Following initial work by Gregoratti and Werner [J. Mod. Optics 50, 913-933, 2003 and quant-ph/0403092] and Hayden and King [quant-ph/0409026], we study the problem of the capacity of a quantum channel assisted by a "friendly (channel) environment" that can locally measure and communicate classical messages to the receiver. Previous work [quant-ph/0505038] has yielded a capacity formula for the quantum capacity under this kind of help from the environment. Here we study the problem of the environment-assisted classical capacity, which exhibits a somewhat richer structure (at least, it seems to be the harder problem). There are several, presumably inequivalent, models of the permitted local operations and classical communications between receiver and environment: one-way, arbitrary, separable and PPT POVMs. In all these models, the task of decoding a message amounts to discriminating a set of possibly entangled states between the two receivers, by a class of operations under some sort of locality constraint. A...

  19. 32 CFR 700.325 - The Assistant Secretary of the Navy (Installations and Environment).

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false The Assistant Secretary of the Navy (Installations and Environment). 700.325 Section 700.325 National Defense Department of Defense (Continued... Assistants § 700.325 The Assistant Secretary of the Navy (Installations and Environment). The Assistant...

  20. Transport Modeling of Hydrogen in Metals for Application to Hydrogen Assisted Cracking of Metals.

    Science.gov (United States)

    1995-04-04

    flank surfaces; net anodic ( dissolution /filming) reactions take place on the bare surface and net cathodic (hydrogen reduction) reactions take place on...ACL 6ij (12) where: p mass density of the solid [kg/m 3 ]. A Lame’ constant [N/mr2]. ij- Kronecker delta (6ij = 1 for i j and 0 otherwise). G shear...the Diffusion of Hydrogen in Iron and Ferritic Steels", Trans. TMS-AIME, Vol. 227, pp. 618-627. 12. B. G. Pound, (1989), "The Application of a

  1. Circular dichroism in laser-assisted proton-hydrogen collisions

    Science.gov (United States)

    Niederhausen, Thomas; Feuerstein, Bernold; Thumm, Uwe

    2004-08-01

    We investigate the effects of a strong laser field on the dynamics of electron capture and emission in ion-atom collisions within a reduced dimensionality model of the scattering system in which the motion of the active electron and the laser electric field vector are confined to the scattering plane. We examine the probabilities for electron capture and ionization as a function of the laser intensity, the projectile impact parameter b , and the laser phase ϕ that determines the orientation of the laser electric field with respect to the internuclear axis at the time of closest approach between target and projectile. Our results for the b -dependent ionization and capture probabilities show a strong dependence on both ϕ and the helicity of the circularly polarized laser light. For intensities above 5×1012W/cm2 our model predicts a noticeable circular dichroism in the capture probability for slow proton-hydrogen collisions, which persists after averaging over ϕ . Capture and electron emission probabilities defer significantly from results for laser-unassisted collisions. Furthermore, we find evidence for a charge-resonance-enhanced ionization mechanism that may enable the measurement of the absolute laser phase ϕ .

  2. Ion beam assisted deposition of hydrogenated amorphous silicon nitride

    Science.gov (United States)

    Hubler, G. K.; Donovan, E. P.; Gossett, C. R.

    1994-06-01

    Hydrogenated silicon nitride films were produced near room temperature by electron beam evaporation of Si and simultaneous bombardment with a 500 eV ammonia ion beam from a Kaufman ion source and for a variety of ratios of incident charge to evaporant fluxes. The composition of N, Si and H in the films as a function of ion current density was measured by means of Rutherford backscattering and elastic recoil detection analyses. Reflection and transmission spectroscopy in the wavelength range 400 nm to 3125 nm were employed to measure optical thickness and refractive index. From the data we extracted the number of nitrogen atoms in the ammonia beam per unit charge collected, the sputtering coefficient for ammonia incident on Si, and the refractive index versus composition of the alloys. At the highest N composition, the films were clear in the visible with the UV cut-off less than 400 nm, the index was 1.80 which is lower than that of pure Si3N4 and the H content was as high as 27 at.%.

  3. Evidences for Cooperative Resonance-Assisted Hydrogen Bonds in Protein Secondary Structure Analogs

    Science.gov (United States)

    Zhou, Yu; Deng, Geng; Zheng, Yan-Zhen; Xu, Jing; Ashraf, Hamad; Yu, Zhi-Wu

    2016-11-01

    Cooperative behaviors of the hydrogen bonding networks in proteins have been discovered for a long time. The structural origin of this cooperativity, however, is still under debate. Here we report a new investigation combining excess infrared spectroscopy and density functional theory calculation on peptide analogs, represented by N-methylformamide (NMF) and N-methylacetamide (NMA). Interestingly, addition of the strong hydrogen bond acceptor, dimethyl sulfoxide, to the pure analogs caused opposite effects, namely red- and blue-shift of the N-H stretching infrared absorption in NMF and NMA, respectively. The contradiction can be reconciled by the marked lowering of the energy levels of the self-associates between NMA molecules due to a cooperative effect of the hydrogen bonds. On the contrary, NMF molecules cannot form long-chain cooperative hydrogen bonds because they tend to form dimers. Even more interestingly, we found excellent linear relationships between changes on bond orders of N-H/N-C/C = O and the hydrogen bond energy gains upon the formation of hydrogen bonding multimers in NMA, suggesting strongly that the cooperativity originates from resonance-assisted hydrogen bonds. Our findings provide insights on the structures of proteins and may also shed lights on the rational design of novel molecular recognition systems.

  4. Modeling Users, Context and Devices for Ambient Assisted Living Environments

    Science.gov (United States)

    Castillejo, Eduardo; Almeida, Aitor; López-de-Ipiña, Diego; Chen, Liming

    2014-01-01

    The participation of users within AAL environments is increasing thanks to the capabilities of the current wearable devices. Furthermore, the significance of considering user's preferences, context conditions and device's capabilities help smart environments to personalize services and resources for them. Being aware of different characteristics of the entities participating in these situations is vital for reaching the main goals of the corresponding systems efficiently. To collect different information from these entities, it is necessary to design several formal models which help designers to organize and give some meaning to the gathered data. In this paper, we analyze several literature solutions for modeling users, context and devices considering different approaches in the Ambient Assisted Living domain. Besides, we remark different ongoing standardization works in this area. We also discuss the used techniques, modeled characteristics and the advantages and drawbacks of each approach to finally draw several conclusions about the reviewed works. PMID:24643006

  5. Numerical Evidence for Robustness of Environment-Assisted Quantum Transport

    CERN Document Server

    Shabani, A; Rabitz., H; Lloyd, S

    2014-01-01

    Recent theoretical studies show that decoherence process can enhance transport efficiency in quantum systems. This effect is known as environment-assisted quantum transport (ENAQT). The role of ENAQT in optimal quantum transport is well investigated, however, it is less known how robust ENAQT is with respect to variations in the system or its environment characteristic. Toward answering this question, we simulated excitonic energy transfer in Fenna-Matthews-Olson (FMO) photosynthetic complex. We found that ENAQT is robust with respect to many relevant parameters of environmental interactions and Frenkel-exciton Hamiltonian including reorganization energy, bath frequency cutoff, temperature, and initial excitations, dissipation rate, trapping rate, disorders, and dipole moments orientations. Our study suggests that the ENAQT phenomenon can be exploited in robust design of highly efficient quantum transport systems.

  6. Numerical evidence for robustness of environment-assisted quantum transport.

    Science.gov (United States)

    Shabani, A; Mohseni, M; Rabitz, H; Lloyd, S

    2014-04-01

    Recent theoretical studies show that decoherence process can enhance transport efficiency in quantum systems. This effect is known as environment-assisted quantum transport (ENAQT). The role of ENAQT in optimal quantum transport is well investigated; however, it is less known how robust ENAQT is with respect to variations in the system or its environment characteristic. Toward answering this question, we simulated excitonic energy transfer in Fenna-Matthews-Olson photosynthetic complex. We found that ENAQT is robust with respect to many relevant parameters of environmental interactions and Frenkel-exciton Hamiltonians, including reorganization energy, bath-frequency cutoff, temperature, initial excitations, dissipation rate, trapping rate, disorders, and dipole moments orientations. Our study suggests that the ENAQT phenomenon can be exploited in robust design of highly efficient quantum transport systems.

  7. Wax: A benign hydrogen-storage material that rapidly releases H2-rich gases through microwave-assisted catalytic decomposition.

    Science.gov (United States)

    Gonzalez-Cortes, S; Slocombe, D R; Xiao, T; Aldawsari, A; Yao, B; Kuznetsov, V L; Liberti, E; Kirkland, A I; Alkinani, M S; Al-Megren, H A; Thomas, J M; Edwards, P P

    2016-10-19

    Hydrogen is often described as the fuel of the future, especially for application in hydrogen powered fuel-cell vehicles (HFCV's). However, its widespread implementation in this role has been thwarted by the lack of a lightweight, safe, on-board hydrogen storage material. Here we show that benign, readily-available hydrocarbon wax is capable of rapidly releasing large amounts of hydrogen through microwave-assisted catalytic decomposition. This discovery offers a new material and system for safe and efficient hydrogen storage and could facilitate its application in a HFCV. Importantly, hydrogen storage materials made of wax can be manufactured through completely sustainable processes utilizing biomass or other renewable feedstocks.

  8. Numerical simulation of hydrogen-assisted crack initiation in austenitic-ferritic duplex steels; Numerische Simulation der wasserstoffunterstuetzten Rissbildung in austentisch-ferritischen Duplexstaehlen

    Energy Technology Data Exchange (ETDEWEB)

    Mente, Tobias

    2015-07-01

    Duplex stainless steels have been used for a long time in the offshore industry, since they have higher strength than conventional austenitic stainless steels and they exhibit a better ductility as well as an improved corrosion resistance in harsh environments compared to ferritic stainless steels. However, despite these good properties the literature shows some failure cases of duplex stainless steels in which hydrogen plays a crucial role for the cause of the damage. Numerical simulations can give a significant contribution in clarifying the damage mechanisms. Because they help to interpret experimental results as well as help to transfer results from laboratory tests to component tests and vice versa. So far, most numerical simulations of hydrogen-assisted material damage in duplex stainless steels were performed at the macroscopic scale. However, duplex stainless steels consist of approximately equal portions of austenite and δ-ferrite. Both phases have different mechanical properties as well as hydrogen transport properties. Thus, the sensitivity for hydrogen-assisted damage is different in both phases, too. Therefore, the objective of this research was to develop a numerical model of a duplex stainless steel microstructure enabling simulation of hydrogen transport, mechanical stresses and strains as well as crack initiation and propagation in both phases. Additionally, modern X-ray diffraction experiments were used in order to evaluate the influence of hydrogen on the phase specific mechanical properties. For the numerical simulation of the hydrogen transport it was shown, that hydrogen diffusion strongly depends on the alignment of austenite and δ-ferrite in the duplex stainless steel microstructure. Also, it was proven that the hydrogen transport is mainly realized by the ferritic phase and hydrogen is trapped in the austenitic phase. The numerical analysis of phase specific mechanical stresses and strains revealed that if the duplex stainless steel is

  9. Uncertainty propagation in modeling of plasma-assisted hydrogen production from biogas

    Science.gov (United States)

    Zaherisarabi, Shadi; Venkattraman, Ayyaswamy

    2016-10-01

    With the growing concern of global warming and the resulting emphasis on decreasing greenhouse gas emissions, there is an ever-increasing need to utilize energy-production strategies that can decrease the burning of fossil fuels. In this context, hydrogen remains an attractive clean-energy fuel that can be oxidized to produce water as a by-product. In spite of being an abundant species, hydrogen is seldom found in a form that is directly usable for energy-production. While steam reforming of methane is one popular technique for hydrogen production, plasma-assisted conversion of biogas (carbon dioxide + methane) to hydrogen is an attractive alternative. Apart from producing hydrogen, the other advantage of using biogas as raw material is the fact that two potent greenhouse gases are consumed. In this regard, modeling is an important tool to understand and optimize plasma-assisted conversion of biogas. The primary goal of this work is to perform a comprehensive statistical study that quantifies the influence of uncertain rate constants thereby determining the key reaction pathways. A 0-D chemical kinetics solver in the OpenFOAM suite is used to perform a series of simulations to propagate the uncertainty in rate constants and the resulting mean and standard deviation of outcomes.

  10. A HYDROGEN BONDING ASSISTED CATALYST SCREENED OUT VIA COMBINATORIAL CHEMISTRY STRATEGY

    Institute of Scientific and Technical Information of China (English)

    XUMancai; OUZhize; 等

    2000-01-01

    Possibilities for enhancement of catalytic reaction rate by combining phase transfer catalysis and hydrogen bonding of the catalyst with the substrate and reagent were studied.A phase transfer catalyst library with sixty polystyrene-supported quaternary ammonium salt catalysts was synthesized.The reduction of acetophenone by NaBH4 was used as the probing reaction to select out the ost active catalyst in the library by using iterative method.which was the gel-type triethanolamine aminsating strongly asic anion exchange resin with the crosslinking degeree of 2% A hydrogen bonding assisted catalytic mechanism was proposed to explain the high catalytic activity of the catalyst.

  11. Effects of hydrogen-bond environment on single particle and pair dynamics in liquid water

    Indian Academy of Sciences (India)

    Amalendu Chandra; Snehasis Chowdhuri

    2001-10-01

    We have performed molecular dynamics simulations of liquid water at 298 and 258 K to investigate the effects of hydrogen-bond environment on various single-particle and pair dynamical properties of water molecules at ambient and supercooled conditions. The water molecules are modelled by the extended simple point charge (SPC/E) model. We first calculate the distribution of hydrogen-bond environment in liquid water at both temperatures and then investigate how the selfdiffusion and orientational relaxation of a single water molecule and also the relative diffusion and relaxation of the hydrogen-bond of a water pair depend on the nature of the hydrogen-bond environment of the tagged molecules. We find that the various dynamical quantities depend significantly on the hydrogen-bond environment, especially at the supercooled temperature. The present study provides a molecular-level insight into the dynamics of liquid water under ambient and supercooled conditions.

  12. Hydrogen embrittlement on {alpha}-iron in high alkaline environment

    Energy Technology Data Exchange (ETDEWEB)

    Hu, R.; Habashi, M.; Galland, J. [Ecole Central Paris, Chatenay-Malabry (France)

    1994-12-31

    The partial pressure of hydrogen in concrete`s pore is very low. This hydrogen is due to the chemical reaction between the silica fumes and the alkaline solutions filling the concrete`s pore. Silica fumes are added in the concrete to increase its compression resistance. If the hydrogen pressure is low, the risk of hydrogen embrittlement is also low. However, for constructional works destined to endure more than 50 years, is this risk negligible? To answer this question, the authors have studied the hydrogen embrittlement on {alpha}-iron in alkaline solutions, in the pH range 9.5 to 13.3, presenting the liquids found in the concrete`s pores after different aging, periods. Cathodic charging has been performed for low current densities in the range 0.25 to 90 A/m{sup 2} simulating several partial pressures of hydrogen on the {alpha}-iron surface with and without EDTA inhibitor. The deformation rate was 2.5{times}10{sup {minus}5} s{sup {minus}1}. Finally {alpha}-iron samples and tensile specimens have been immersed in a mixture of silica fumes and an alkaline solution at pH 13.3 in an autoclave during 1,000 hours with the aim to measure the outgassed quantity of hydrogen under vacuum at 600C and to measure also the hydrogen embrittlement. The main conclusions of this study are as following: (1) Hydrogen embrittlement is promoted by oxide Fe{sub 3}O{sub 4} film rupture and/or hydroxide Fe(OH){sub 2}. This mechanism is efficient for current densities equivalent to a cathodic potential lower or equal to {minus}1V/NHE. (2) Silica fumes in contact with a solution of pH 13.3 provoke hydrogen release and its diffusion into the {alpha}-iron, but this quantity is not enough to embrittle it.

  13. The influence of hydrogen on the fatigue life of metallic leaf spring components in a vacuum environment

    NARCIS (Netherlands)

    Kouters, M.H.M.; Slot, H.M.; Zwieten, W. van; Veer, J. van der

    2014-01-01

    Hydrogen is used as a process gas in vacuum environments for semiconductor manufacturing equipment. If hydrogen dissolves in metallic components during operation it can result in hydrogen embrittlement. In order to assess if hydrogen embrittlement occurs in such a vacuum environment a special fatigu

  14. Ultrasonochemical-Assisted Synthesis of CuO Nanorods with High Hydrogen Storage Ability

    Directory of Open Access Journals (Sweden)

    Gang Xiao

    2011-01-01

    Full Text Available Uniform CuO nanorods with different size have been synthesized in a water-alcohol solution through a fast and facile ultrasound irradiation assistant route. Especially, the as-prepared CuO nanorods have shown a strong size-induced enhancement of electrochemical hydrogen storage performance and exhibit a notable hydrogen storage capacity and big BET surface area. These results further implied that the as-prepared CuO nanorods could be a promising candidate for electrochemical hydrogen storage applications. The observation of the comparison experiments with different concentrations of NaOH, ethanol, CTAB, and HTMA while keeping other synthetic parameters unchanged leads to the morphology and size change of CuO products.

  15. Thermally assisted tunneling of hydrogen in silicon: A path-integral Monte Carlo study

    Science.gov (United States)

    Herrero, Carlos P.

    1997-04-01

    Quantum transition-state theory, based on the path-integral formalism, has been applied to study the jump rate of atomic hydrogen and deuterium in crystalline silicon. This technique provides a methodology to study the influence of vibrational mode quantization and quantum tunneling on the impurity jump rate. The atomic interactions were modeled by effective potentials, fitted to earlier ab initio pseudopotential calculations. Silicon nuclei were treated as quantum particles up to second-nearest neighbors of the impurity. The hydrogen jump rate follows an Arrhenius law, describable with classical transition-state theory, at temperatures higher than 100 K. At ~80 K, a change in the slope of the Arrhenius plot is obtained for hydrogen, as expected for the onset of a diffusion regime controlled by phonon-assisted tunneling of the impurity. For deuterium, no change of slope is observed in the studied temperature range (down to 40 K).

  16. Investigation of hydrogen assisted cracking in acicular ferrite using site-specific micro-fracture tests

    Energy Technology Data Exchange (ETDEWEB)

    Costin, Walter L. [School of Mechanical Engineering, The University of Adelaide, SA 5005 (Australia); Lavigne, Olivier, E-mail: Olivier.lavigne@adelaide.edu.au [School of Mechanical Engineering, The University of Adelaide, SA 5005 (Australia); Kotousov, Andrei; Ghomashchi, Reza [School of Mechanical Engineering, The University of Adelaide, SA 5005 (Australia); Linton, Valerie [Energy Pipelines Cooperative Research Centre, Faculty of Engineering, University of Wollongong, NSW 2522 (Australia)

    2016-01-10

    Hydrogen assisted cracking (HAC) is a common type of failure mechanism that can affect a wide range of metals and alloys. Experimental studies of HAC are cumbersome due to various intrinsic and extrinsic parameters and factors (associated with stress, hydrogen and the materials microstructure) contributing to the hydrogen crack kinetics. The microstructure of many materials consists of diverse constituents with characteristic features and mechanical properties which only occur in very small material volumes. The only way to differentiate the effect of these individual constituents on the hydrogen crack kinetics is to miniaturise the testing procedures. In this paper we present a new experimental approach to investigate hydrogen assisted crack growth in a microstructural constituent, i.e. acicular ferrite. For this purpose, sharply notched micro-cantilevers were fabricated with a Focus Ion Beam within this selected microscopic region. Acicular ferrite can be found in many ferrous alloys including ferritic weld metal and has specific features that control its intrinsic susceptibility to HAC. These features were characterised via Electron Backscatter Diffraction and the specimens were subsequently loaded under uncharged and hydrogen charged conditions with a nano-indenter. The outcomes of the testing, demonstrated that the threshold stress intensity factor, K{sub th}, to initiate crack propagation in acicular ferrite ranges between 1.56 MPa m{sup 1/2} and 4.36 MPa m{sup 1/2}. This range is significantly below the values of K{sub th} reported for various ferrous alloys in standard macro-tests. This finding indicates that the mechanisms and resistance to HAC at micro-scale could be very different than at the macro-scale as not all fracture toughening mechanisms may be activated at this scale level.

  17. Minimising hydrogen sulphide generation during steam assisted production of heavy oil

    Science.gov (United States)

    Montgomery, Wren; Sephton, Mark A.; Watson, Jonathan S.; Zeng, Huang; Rees, Andrew C.

    2015-02-01

    The majority of global petroleum is in the form of highly viscous heavy oil. Traditionally heavy oil in sands at shallow depths is accessed by large scale mining activities. Recently steam has been used to allow heavy oil extraction with greatly reduced surface disturbance. However, in situ thermal recovery processes can generate hydrogen sulphide, high levels of which are toxic to humans and corrosive to equipment. Avoiding hydrogen sulphide production is the best possible mitigation strategy. Here we use laboratory aquathermolysis to reproduce conditions that may be experienced during thermal extraction. The results indicate that hydrogen sulphide generation occurs within a specific temperature and pressure window and corresponds to chemical and physical changes in the oil. Asphaltenes are identified as the major source of sulphur. Our findings reveal that for high sulphur heavy oils, the generation of hydrogen sulphide during steam assisted thermal recovery is minimal if temperature and pressure are maintained within specific criteria. This strict pressure and temperature dependence of hydrogen sulphide release can allow access to the world's most voluminous oil deposits without generating excessive amounts of this unwanted gas product.

  18. Effects of hydrogen environment on fatigue characteristics of 18Cr-8Ni stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kawamoto, K.; Aoki, Y.; Oda, Y.; Yoshimura, T.; Noguchi, H.; Higashida, K. [Hakozaki, Higashi-ku, Fukuoka (Japan)

    2005-07-01

    In order to clarify the effects of hydrogen on the fatigue characteristics of an austenitic stainless steel, bending fatigue tests were conducted in air, in a hydrogen gas and in a nitrogen gas. Main results obtained are as follows. Effects of hydrogen gas environment are not clearly seen on the strain range - fatigue life diagram, because there are opposite effects to crack propagation and to crack initiation; accelerates crack propagation, but retards crack initiation. Striation spacing or in-situ observation confirms the acceleration. The retardation seems to be attributed to the absence of oxygen or water vapor in the hydrogen gas. (orig.)

  19. Hydrogen, carbon monoxide, and methane in the marine environment

    OpenAIRE

    Bullister, John Logan

    1980-01-01

    EXTRACT (SEE PDF FOR FULL ABSTRACT): The horizontal and vertical distribution of three dissolved trace gases, namely molecular hydrogen, carbon monoxide, and methane, was measured in coastal and oceanic areas. Atmospheric concentrations of these gases were measured both at locations influenced by nearby human activity, and in areas far removed from these inputs.

  20. Membrane contactor assisted water extraction system for separating hydrogen peroxide from a working solution, and method thereof

    Science.gov (United States)

    Snyder, Seth W.; Lin, Yupo J.; Hestekin' Jamie A.; Henry, Michael P.; Pujado, Peter; Oroskar, Anil; Kulprathipanja, Santi; Randhava, Sarabjit

    2010-09-21

    The present invention relates to a membrane contactor assisted extraction system and method for extracting a single phase species from multi-phase working solutions. More specifically one preferred embodiment of the invention relates to a method and system for membrane contactor assisted water (MCAWE) extraction of hydrogen peroxide (H.sub.2O.sub.2) from a working solution.

  1. Preparation of hydrogenated microcrystalline silicon films with hot-wire-assisted MWECR-CVD system

    Institute of Scientific and Technical Information of China (English)

    He Bin; Chen Guang-Hua; Zhu Xiu-Hong; Zhang Wen-Li; Ding Yi; Ma Zhan-Jie; Gao Zhi-Hua; Song Xue-Mei; Deng Jin-Xiang

    2006-01-01

    Intrinsic hydrogenated microcrystalline silicon (μc-Si:H) films have been prepared by hot-wire-assisted microwave electron-cyclotron-resonance chemical vapour deposition (Hw-MwECR-CVD) under different deposition conditions.Fourier-transform infrared spectra and Raman spectra were measured.Optical band gap WaS determined by Tauc plots,and experiments of photo-induced degradation were performed.It was observed that hydrogen dilution plays a more essential role than substrate temperature in microcrystalline transformation at low temperatures. Crystalline volume fraction and mean grain size in the films increase with the dilution ratio (R=H2/(H2+SiH4)).With the rise of crystallinity in the films,the optical band gap tends to become narrower while the hydrogen content and photo-induced degradation decrease dramatically.The samples,were identified as μc-Si:H films,by calculating the optical band gap.It is considered that hydrogen dilution has an effect on reducing the crystallization activation energy of the material,which promotes the heterogeneous solid-state phase transition characterized by the Johnson-Mehl-Avrami (JMA) equation.The films with the needed structure can be prepared by balancing deposition and crystaUization through controlling process parameters.

  2. Modulation of Carbon Nanotube Metal Contacts in Gaseous Hydrogen Environment

    Directory of Open Access Journals (Sweden)

    A. R. Usgaocar

    2014-01-01

    Full Text Available Carbon nanotubes (CNTs, contacted by electrodeposited Pd0.59Ni0.41 alloys, are characterised using electrical measurements and Raman spectroscopy. The high workfunctions of Nickel and Palladium form an ohmic contact with the CNT valence band, but the contact properties change on Hydrogen exposure due to a reduction in the PdNi workfunction and the realignment of the PdNi Fermi level with the CNT band structure. A PdNi contacted semiconducting CNT exhibited significantly lower currents after Hydrogen exposure while a metallic CNT exhibited a small current increase. The semiconducting and metallic natures of the CNTs are confirmed by their Raman spectra. This study demonstrates a technique for modulating the PdNi-CNT contact and differentiating between semiconducting and metallic CNTs via contact modulation. It also provides experimental evidence of the theoretical allocation of features in the CNT Raman spectra.

  3. Hydrogenation of diesel aromatic compounds in supercritical solvent environment

    Directory of Open Access Journals (Sweden)

    E.P. Martins

    2000-09-01

    Full Text Available Reactions under supercritical conditions have been employed in many processes. Furthermore, an increasing number of commercial reactions have been conducted under supercritical or near critical conditions. These reaction conditions offer several advantages when compared to conditions in conventional catalytic processes in liquid-phase, gas-liquid interface, or even some gas-phase reactions. Basically, a supercritical solvent can diminish the reactant’s transport resistance from the bulk region to the catalyst surface due to enhancement of liquid diffusivity values and better solubility than those in different phases. Another advantage is that supercritical solvents permit prompt and easy changes in intermolecular properties in order to modify reaction parameters, such as conversion or selectivity, or even proceed with the separation of reaction products. Diesel fractions from petroleum frequently have larger than desirable quantities of aromatic compounds. Diesel hydrogenation is intended to decrease these quantities, i.e., to increase the quantity of paraffin present in this petroleum fraction. In this work, the hydrogenation of tetralin was studied as a model reaction for the aromatic hydrogenation process. A conventional gas-liquid-solid catalytic process was compared with that of supercritical carbon dioxide substrate under similar conditions. Additionally, an equilibrium conversion diagram was calculated for this reaction in a wide range of temperature and reactant ratios, so as to optimize the operational conditions and improve the results of subsequent experiments. An increase in the rate of reaction at 493 K in supercritical fluid, as compared to that in the conventional process, was observed.

  4. Hydrogenation of diesel aromatic compounds in supercritical solvent environment

    Energy Technology Data Exchange (ETDEWEB)

    Martins, E.P.; Aranda, D.A.G.; Pessoa, F.L.P. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept. de Engenharia Quimica. E-mail: donato@h2o.eq.ufrj.br; pessoa@h2o.eq.ufrj.br; Zotin, J.L. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. E-mail: zotin@cenpes.petrobras.com.br

    2000-09-01

    Reactions under supercritical conditions have been employed in many processes. Furthermore, an increasing number of commercial reactions have been conducted under supercritical or near critical conditions. These reaction conditions offer several advantages when compared to conditions in conventional catalytic processes in liquid-phase, gas-liquid interface., or even some gas-phase reactions. basically, a supercritical solvent can diminish the reactant's transport resistance from the bulk region to the catalyst surface due to enhancement of liquid diffusivity values and better solubility than those in different phases. Another advantage is that supercritical solvents permit prompt and easy changes in intermolecular properties in order to modify reaction parameters, such as conversion or selectivity, or even proceed with the separation of reaction products. Diesel fractions from petroleum frequently have larger than desirable quantities of aromatic compounds. Diesel hydrogenation is intended to decrease these quantities, to increase the quantity of paraffin present in this petroleum fraction. In this work, the hydrogenation of tetralin was studied as a model reaction for the aromatic hydrogenation process. A conventional gas-liquid-solid catalytic process was compared with that of supercritical carbon dioxide substrate under similar conditions. Additionally, an equilibrium conversion diagram was calculated for this reaction in a wide range of temperature and reactant ratios, so as to optimize the operational conditions and improve the results of subsequent experiments. An increase in the rate of reaction at 493 K in supercritical fluid, as compared to that in the conventional process, was observed. (author)

  5. Laser and optical system for laser assisted hydrogen ion beam stripping at SNS

    Science.gov (United States)

    Liu, Y.; Rakhman, A.; Menshov, A.; Webster, A.; Gorlov, T.; Aleksandrov, A.; Cousineau, S.

    2017-03-01

    Recently, a high-efficiency laser assisted hydrogen ion (H-) beam stripping was successfully carried out in the Spallation Neutron Source (SNS) accelerator. The experiment was not only an important step toward foil-less H- stripping for charge exchange injection, it also set up a first example of using megawatt ultraviolet (UV) laser source in an operational high power proton accelerator facility. This paper reports in detail the design, installation, and commissioning result of a macro-pulsed multi-megawatt UV laser system and laser beam transport line for the laser stripping experiment.

  6. Study on hydrogen assisted cracking susceptibility of HSLA steel by implant test

    OpenAIRE

    2016-01-01

    DMR-249A is an indigenously developed high strength low alloy steel for Indian ship building industry for making ship-hull and is extensively used in the construction of war ships and submarines. Welding electrodes conforming to SFA 5.5 AWS E8018 C1 has been indigenously developed for welding of this steel using shielded metal arc welding process. In the present study, susceptibility to hydrogen assisted cracking of DMR-249A steel welds made using this electrode has been assessed using implan...

  7. A Simulation to Evaluate Joint Military Logistics in a Humanitarian Assistance Environment

    Science.gov (United States)

    2012-03-01

    A SIMULATION TO EVALUATE JOINT MILITARY LOGISTICS IN A HUMANITARIAN ASSISTANCE ENVIRONMENT THESIS...protection in the United States. AFIT/LSCM/ENS/12-04 A SIMULATION TO EVALUATE JOINT MILITARY LOGISTICS IN A HUMANITARIAN ASSISTANCE ENVIRONMENT...FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT/LSCM/ENS/12-04 A SIMULATION TO EVALUATE JOINT MILITARY LOGISTICS IN A HUMANITARIAN

  8. Assisting personal positioning in indoor environments using map matching

    Science.gov (United States)

    Attia, M.; Moussa, A.; Zhao, X.; El-Sheimy, N.

    2011-12-01

    Personal positioning is facing a huge challenge to maintain a reliable accuracy through all applications. Although in outdoor applications, several mobile navigation devices can provide acceptable positioning accuracy, the situation in indoor environment is not the same. Mobile navigation devices mainly contain a global positioning system (GPS) receiver and an inertial measurement unit (IMU). The main drawback in indoor navigation applications is the unavailability of the GNSS signals, which decreases the possibility of obtaining an accurate absolute position solution, as the inertial system (INS) solution will drift with time in the absence of external updates. Several alternatives were presented lately to update the inertial solution such as using Wi-Fi, UWB, RFID, several self-contained sensors, imaging aiding and spatial information aiding. In order to achieve accurate position solution, with low-cost and usable technique, an integrated mobile navigation system integrating GPS/IMU/Wi-Fi and map-matching was developed. The developed system uses the prior knowledge of the indoor geometrical and topological information, as a threshold for the navigation solution, forcing the provided solution to be mostly on the right track. The geometrical and topological information for the building was used to build the geospatial data model. The use of this model was performed by developing a map matching algorithm which uses the geometrical and topological characteristics of the building to locate the user position on the building map. This algorithm was developed based on the geospatial information of the Engineering building, University of Calgary, where the field test occurred. The map-matching algorithm was evaluated by processing and comparing two separate navigation solutions through the study area, one using only the GPS/IMU/Wi-Fi system, and second solution was assisted with the map-matching algorithm which shows significant enhancement in the position solution for

  9. Wax: A benign hydrogen-storage material that rapidly releases H2-rich gases through microwave-assisted catalytic decomposition

    Science.gov (United States)

    Gonzalez-Cortes, S.; Slocombe, D. R.; Xiao, T.; Aldawsari, A.; Yao, B.; Kuznetsov, V. L.; Liberti, E.; Kirkland, A. I.; Alkinani, M. S.; Al-Megren, H. A.; Thomas, J. M.; Edwards, P. P.

    2016-01-01

    Hydrogen is often described as the fuel of the future, especially for application in hydrogen powered fuel-cell vehicles (HFCV’s). However, its widespread implementation in this role has been thwarted by the lack of a lightweight, safe, on-board hydrogen storage material. Here we show that benign, readily-available hydrocarbon wax is capable of rapidly releasing large amounts of hydrogen through microwave-assisted catalytic decomposition. This discovery offers a new material and system for safe and efficient hydrogen storage and could facilitate its application in a HFCV. Importantly, hydrogen storage materials made of wax can be manufactured through completely sustainable processes utilizing biomass or other renewable feedstocks. PMID:27759014

  10. Hydrogen-bond interaction assisted branched copolymer HILIC material for separation and N-glycopeptides enrichment.

    Science.gov (United States)

    Shao, Wenya; Liu, Jianxi; Yang, Kaiguang; Liang, Yu; Weng, Yejing; Li, Senwu; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-09-01

    Hydrophilic interaction chromatography (HILIC) has attracted increasing attention in recent years due to its efficient application in the separation of polar compounds and the enrichment of glycopeptides. However, HILIC materials are still of weak hydrophilicity and thereby present weak retention and selectivity. In this work, branched copolymer modified hydrophilic material Sil@Poly(THMA-co-MBAAm), with high hydrophilicity and unique "claw-like" polyhydric groups, were prepared by "grafting from" thiol-ene click reaction. Due to the abundant functional groups provided by branched copolymer, the material showed excellent retention for nucleosides, necleobases, acidic compounds, sugars and peptides. Furthermore, Sil@Poly(THMA-co-MBAAm) was also applied for the N-glycosylation sites profiling towards the digests of the mouse brain, and 1997N-glycosylated peptides were identified, corresponding to 686 glycoprotein groups. Due to the assisted hydrogen-bond interaction, the selectivity for glycopeptide enrichment in the real sample reached 94.6%, which was the highest as far as we know. All these results indicated that such hydrogen-bond interaction assisted branched copolymer HILIC material possessed great potential for the separation and large scale glycoproteomics analysis.

  11. Investigating walking environments in and around assisted living facilities: a facility visit study.

    Science.gov (United States)

    Lu, Zhipeng

    2010-01-01

    This study explores assisted living residents' walking behaviors, locations where residents prefer to walk, and walking environments in and around assisted living facilities. Regular walking is beneficial to older adults' physical and psychological health. Yet frail older residents in assisted living are usually too sedentary to achieve these benefits. The physical environment plays an important role in promoting physical activity. However, there is little research exploring this relationship in assisted living settings. The researcher visited 34 assisted living facilities in a major Texas city. Methods included walk-through observation with the Assisted Living Facility Walking Environment Checklist, and interviews with administrators by open- and close-ended questions. The data from 26 facilities were analyzed using descriptive statistics (for quantitative data) and content analysis (for qualitative data). The results indicate that (a) residents were walking both indoors and outdoors for exercise or other purposes (e.g., going to destinations); (b) assisted living facility planning and design details-such as neighborhood sidewalk conditions, facility site selection, availability of seating, walking path configuration (e.g., looped/nonlooped path), amount of shading along the path, presence of handrails, existence of signage, etc.-may influence residents' walking behaviors; and (c) current assisted living facilities need improvement in all aspects to make their environments more walkable for residents. Findings of the study provide recommendations for assisted living facilities to improve the walkability of environments and to create environmental interventions to promote regular walking among their residents. This study also implies several directions for future research.

  12. The pipeline fracture behavior and pressure assessment under HIC (Hydrogen induced cracking) environment

    Energy Technology Data Exchange (ETDEWEB)

    Shaohua, Dong [China National Petroleum Corporation (CNPC), Beijing (China); Lianwei, Wang [University of Science and Technology Beijing (USTB), Beijing (China)

    2009-07-01

    As Hydrogen's transmit and diffuse, after gestating for a while, the density of hydrogen around crack tip of pipeline will get to the critical density, and the pipeline material will descend, make critical stress factor, the reason of pipeline Hydrogen Induced Cracking is Hydrogen's transmit and diffuse. The stress factor of Hydrogen Induced Cracking under surroundings-condition of stress is the key that estimate material's rupture behavior. The paper study the relationship among hydrogen concentrate, crack tip stress, stain field, hydrogen diffusion and inner pressure for crack tip process zone, then determined the length of HIC (hydrogen induced cracking) process zone. Based on the theory of propagation which reason micro-crack making core, dislocation model is produced for fracture criteria of HIC, the influence between material and environments under the HIC is analyzed, step by step pipeline maximum load pressure and threshold of J-integrity ( J{sub ISCC} ) is calculated, which is very significant for pipeline safety operation. (author)

  13. Effects of Low Temperature on Hydrogen-Assisted Crack Growth in Forged 304L Austenitic Stainless Steel

    Science.gov (United States)

    Jackson, Heather; San Marchi, Chris; Balch, Dorian; Somerday, Brian; Michael, Joseph

    2016-08-01

    The objective of this study was to evaluate effects of low temperature on hydrogen-assisted crack propagation in forged 304L austenitic stainless steel. Fracture initiation toughness and crack-growth resistance curves were measured using fracture mechanics specimens that were thermally precharged with 140 wppm hydrogen and tested at 293 K or 223 K (20 °C or -50 °C). Fracture initiation toughness for hydrogen-precharged forgings decreased by at least 50 to 80 pct relative to non-charged forgings. With hydrogen, low-temperature fracture initiation toughness decreased by 35 to 50 pct relative to room-temperature toughness. Crack growth without hydrogen at both temperatures was microstructure-independent and indistinguishable from blunting, while with hydrogen microcracks formed by growth and coalescence of microvoids. Initiation of microvoids in the presence of hydrogen occurred where localized deformation bands intersected grain boundaries and other deformation bands. Low temperature additionally promoted fracture initiation at annealing twin boundaries in the presence of hydrogen, which competed with deformation band intersections and grain boundaries as sites of microvoid formation and fracture initiation. A common ingredient for fracture initiation was stress concentration that arose from the intersection of deformation bands with these microstructural obstacles. The localized deformation responsible for producing stress concentrations at obstacles was intensified by low temperature and hydrogen. Crack orientation and forging strength were found to have a minor effect on fracture initiation toughness of hydrogen-supersaturated 304L forgings.

  14. Application of Hydrogen Assisted Lean Operation to Natural Gas-Fueled Reciprocating Engines (HALO)

    Energy Technology Data Exchange (ETDEWEB)

    Chad Smutzer

    2006-01-01

    Two key challenges facing Natural Gas Engines used for cogeneration purposes are spark plug life and high NOx emissions. Using Hydrogen Assisted Lean Operation (HALO), these two keys issues are simultaneously addressed. HALO operation, as demonstrated in this project, allows stable engine operation to be achieved at ultra-lean (relative air/fuel ratios of 2) conditions, which virtually eliminates NOx production. NOx values of 10 ppm (0.07 g/bhp-hr NO) for 8% (LHV H2/LHV CH4) supplementation at an exhaust O2 level of 10% were demonstrated, which is a 98% NOx emissions reduction compared to the leanest unsupplemented operating condition. Spark ignition energy reduction (which will increase ignition system life) was carried out at an oxygen level of 9%, leading to a NOx emission level of 28 ppm (0.13 g/bhp-hr NO). The spark ignition energy reduction testing found that spark energy could be reduced 22% (from 151 mJ supplied to the coil) with 13% (LHV H2/LHV CH4) hydrogen supplementation, and even further reduced 27% with 17% hydrogen supplementation, with no reportable effect on NOx emissions for these conditions and with stable engine torque output. Another important result is that the combustion duration was shown to be only a function of hydrogen supplementation, not a function of ignition energy (until the ignitability limit was reached). The next logical step leading from these promising results is to see how much the spark energy reduction translates into increase in spark plug life, which may be accomplished by durability testing.

  15. Control of Hydrogen Environment Embrittlement of Ultra-High Strength Steel for Naval Application

    Science.gov (United States)

    2005-07-01

    correlated with diffusible H concentration reported for AISI 4340-type the specific microstructural features of AERMIET 100, and steels[28’ 29’ 301 as well...demonstrated severe internal hydrogen assisted cracking in low alloy steels such as AISI 4340 (Johnson et al., 1958; Steigerwald et al., 1960; Troiano, 1960...martensitic steels such as AISI 4340, not processed for impurity control, as well as in higher purity maraging steels (Fig. 3) (McMahon, 2001; Eliaz et al

  16. Relativistic electronic dressing in laser-assisted ionization of atomic hydrogen by electron impact

    CERN Document Server

    Attaourti, Y

    2004-01-01

    Within the framework of the coplanar binary geometry where it is justified to use plane wave solutions for the study of the $(e,2e)$ reaction and in the presence of a circularly polarized laser field, we introduce as a first step the DVRPWBA1 (Dirac-Volkov Plane Wave Born Approximation1) where we take into account only the relativistic dressing of the incident and scattered electrons. Then, we introduce the DVRPWBA2 (Dirac-Volkov Plane Wave Born Approximation2) where we take totally into account the relativistic dressing of the incident, scattered and ejected electrons. We then compare the corresponding triple differential cross sections for laser-assisted ionization of atomic hydrogen by electron impact both for the non relativistic and the relativistic regime.

  17. SuperAssist: A User-Assistant Collaborative Environment for the supervision of medical instrument use at home

    NARCIS (Netherlands)

    Blanson Henkemans, O.A.; Neerincx, M.A.; Lindenberg, J.; Mast, C.A.P.G. van der

    2007-01-01

    With the rise of Transmural care, patients increasingly use medical instruments at home. Maintenance and troubleshooting greatly determines the safety and accuracy of these instruments. For the supervision of these complex tasks, we developed a User-Assistant Collaborative Environment (U-ACE). We

  18. Laser-Assisted Semi Relativistic Excitation of Atomic Hydrogen by Electronic Impact

    CERN Document Server

    Taj, S; Idrissi, M El; Oufni, L

    2012-01-01

    The excitation of H ($1s-2s$) by electron impact in the presence and in the absence of the laser field is studied in the framework of the first Born approximation. The angular variation of the laser-assisted differential cross section (DCS) for atomic hydrogen by electronic impact is presented at various kinetic energies for the incident electron. The use of Darwin wave function as a semirelativistic state to represent the atomic hydrogen gives interesting results when the condition $z/c\\ll1$ is fulfilled. A comparison with the non relativistic theory and experimental data gives good agreement. It was observed that beyond (2700 $eV$) which represents the limit between the two approaches, the non relativistic theory does not yield close agreement with our theory and that, over certain ranges of energy, it can be in error by several orders of magnitude. The sum rule given by Bunkin and Fedorov and by Kroll and Watson \\cite{22} has been verified in both nonrelativistic and relativistic regimes.

  19. The nature of resonance-assisted hydrogen bonds: a quantum chemical topology perspective.

    Science.gov (United States)

    Guevara-Vela, José Manuel; Romero-Montalvo, Eduardo; Costales, Aurora; Pendás, Ángel Martín; Rocha-Rinza, Tomás

    2016-10-14

    Resonance Assisted Hydrogen Bonds (RAHBs) are particularly strong H-Bonds (HBs) which are relevant in several fields of chemistry. The traditional explanation for the occurrence of these HBs is built on mesomeric structures evocative of electron delocalisation in the system. Nonetheless, there are several theoretical studies which have found no evidence of such electron delocalisation. We considered the origin of RAHBs by employing Quantum Chemical Topology tools, more specifically, the Quantum Theory of Atoms in Molecules (QTAIM) and the Interacting Quantum Atoms energy partition. Our results indicate that the π-conjugated bonds allow for a larger adjustment of electron density throughout the H-bonded system as compared with non-conjugated carbonyl molecules. This rearrangement of charge distribution is a response to the electric field due to the H atom involved in the hydrogen bonding of the considered compounds. As opposed to the usual description of RAHB interactions, these HBs lead to a larger electron localisation in the system, and concomitantly to larger QTAIM charges which in turn lead to stronger electrostatic, polarization and charge transfer components of the interaction. Overall, the results presented here offer a new perspective on the cause of strengthening of these important interactions.

  20. Hydrogen Assisted Crack in Dissimilar Metal Welds for Subsea Service under Cathodic Protection

    Science.gov (United States)

    Bourgeois, Desmond

    Dissimilar metal welds (DMWs) are routinely used in the oil and gas industries for structural joining of high strength steels in order to eliminate the need for post weld heat treatment (PWHT) after field welding. There have been reported catastrophic failures in these DMWs, particularly the AISI 8630 steel - Alloy 625 DMW combination, during subsea service while under cathodic protection (CP). This is due to local embrittlement that occurs in susceptible microstructures that are present at the weld fusion boundary region. This type of cracking is known as hydrogen assisted cracking (HAC) and it is influenced by base/filler metal combination, and welding and PWHT procedures. DMWs of two material combinations (8630 steel -- Alloy 625 and F22 steel -- Alloy 625), produced with two welding procedures (BS1 and BS3) in as welded and PWHT conditions were investigated in this study. The main objectives included: 1) evaluation of the effect of materials composition, welding and PWHT procedures on the gradients of composition, microstructure, and properties in the dissimilar transition region and on the susceptibility to HAC; 2) investigation of the influence of microstructure on the HAC failure mechanism and identification of microstructural constituents acting as crack nucleation and propagation sites; 3) assessment of the applicability of two-step PWHT to improve the resistance to HAC in DMWs; 4) establishment of non-failure criterion for the delayed hydrogen cracking test (DHCT) that is applicable for qualification of DMWs for subsea service under cathodic protection (CP).

  1. A Rapid Microwave-Assisted Thermolysis Route to Highly Crystalline Carbon Nitrides for Efficient Hydrogen Generation.

    Science.gov (United States)

    Guo, Yufei; Li, Jing; Yuan, Yupeng; Li, Lu; Zhang, Mingyi; Zhou, Chenyan; Lin, Zhiqun

    2016-11-14

    Highly crystalline graphitic carbon nitride (g-C3 N4 ) with decreased structural imperfections benefits from the suppression of electron-hole recombination, which enhances its hydrogen generation activity. However, producing such g-C3 N4 materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high-quality g-C3 N4 with reduced structural defects by judiciously combining the implementation of melamine-cyanuric acid (MCA) supramolecular aggregates and microwave-assisted thermolysis. The g-C3 N4 material produced after optimizing the microwave reaction time can effectively generate H2 under visible-light irradiation. The highest H2 evolution rate achieved was 40.5 μmol h(-1) , which is two times higher than that of a g-C3 N4 sample prepared by thermal polycondensation of the same supramolecular aggregates in an electric furnace. The microwave-assisted thermolysis strategy is simple, rapid, and robust, thereby providing a promising route for the synthesis of high-efficiency g-C3 N4 photocatalysts. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. ULTRASOUND-ASSISTED EPOXIDATION OF OLEFINS AND A,B-UNSATURATED KETONES OVER HYDROTALCITES USING HYDROGEN PEROXIDE

    Science.gov (United States)

    An efficient ultrasound-assisted epoxidation of olefins and a,B-unsaturated ketones over hydrotacite catalysts in the presence of hydrogen peroxide and acetonitrile is described. This general and selective protocol is relatively fast and is applicable to a wide variety of substra...

  3. Corrosion Rate of Hydrogenation to C110 Casing in High H2S Environment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi; LI Changjin; ZHANG Jiyin; SHI Taihe

    2012-01-01

    The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied,and a basis for the materials selection of sour gas well bushing was provided in H2S,CO2 and saline coexisting environment.Under acidic condiction,hydrogen atoms greatly entered into the material and caused the material properties changed.Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment.PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated,hydrogen charging after reacting in autoclave.The corrosion product film was observed through SEM.The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time.Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film.A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix,but cracked holes which will accelerate partial corrosion of the sample were also observed.

  4. Ultrasonic assisted synthesis of Bikitaite zeolite: A potential material for hydrogen storage application.

    Science.gov (United States)

    Roy, Priyanka; Das, Nandini

    2017-05-01

    Li containing Bikitaite zeolite has been synthesized by an ultrasound-assisted method and used as a potential material for hydrogen storage application. The Sonication energy was varied from 150W to 250W and irradiation time from 3h to 6h. The Bikitaite nanoparticles were characterized by X-ray diffraction (XRD), infrared (IR) spectral analysis, and field-emission scanning electron microscopy (FESEM) thermo-gravimetrical analysis and differential thermal analysis (TGA, DTA). XRD and IR results showed that phase pure, nano crystalline Bikitaite zeolites were started forming after 3h irradiation and 72h of aging with a sonication energy of 150W and nano crystalline Bikitaite zeolite with prominent peaks were obtained after 6h irradiation of 250W sonic energy. The Brunauer-Emmett-Teller (BET) surface area of the powder by N2 adsorption-desorption measurements was found to be 209m(2)/g. The TEM micrograph and elemental analysis showed that desired atomic ratio of the zeolite was obtained after 6h irradiation. For comparison, sonochemical method, followed by the hydrothermal method, with same initial sol composition was studied. The effect of ultrasonic energy and irradiation time showed that with increasing sonication energy, and sonication time phase formation was almost completed. The FESEM images revealed that 50nm zeolite crystals were formed at room temperature. However, agglomerated particles having woollen ball like structure was obtained by sonochemical method followed by hydrothermal treatment at 100°C for 24h. The hydrogen adsorption capacity of Bikitaite zeolite with different Li content, has been investigated. Experimental results indicated that the hydrogen adsorption capacities were dominantly related to their surface areas as well as total pore volume of the zeolite. The hydrogen adsorption capacity of 143.2c.c/g was obtained at 77K and ambient pressure of (0.11MPa) for the Bikitaite zeolite with 100% Li, which was higher than the reported values for

  5. Care assistant experiences of dementia care in long-term nursing and residential care environments.

    Science.gov (United States)

    Talbot, Rebecca; Brewer, Gayle

    2016-11-01

    Care assistants have a unique insight into the lives of service users and those factors which may impede or enhance the delivery of high quality dementia oriented care. To address the paucity of research in this area, the present study examined care assistant experiences of dementia care in British long-term residential and nursing environments. Semi-structured interviews were conducted with eight care assistants and transcripts were analysed using interpretive phenomenological analysis. Super-ordinate themes emerging from the data were psychological wellbeing of the care assistant, barriers to effective dementia care, the dementia reality and organisational issues within the care environment. The study revealed important deficiencies in understanding and varying levels of dementia training. Whilst person centred strategies were being implemented, task orientated care remained dominant. Furthermore, care assistants reported taking the perspectives of those with dementia into account, and actively using these to develop relationship centred care.

  6. High yield simultaneous hydrogen and ethanol production under extreme-thermophilic (70 C) mixed culture environment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chenxi [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby (Denmark); O-Thong, Sompong [Department of Biology, Faculty of Science, Thaksin University, Patthalung 93110 (Thailand); Karakashev, Dimitar; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby (Denmark); Lu, Wenjing; Wang, Hongtao [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2009-07-15

    The effect of pH and medium composition on extreme-thermophilic (70 C) dark fermentative simultaneous hydrogen and ethanol production (process performance and microbial ecology) was investigated. Hydrogen and ethanol yields were optimized with respect to glucose, peptone, FeSO{sub 4}, NaHCO{sub 3}, yeast extract, trace mineral salts, vitamins, and phosphate buffer concentrations as well as initial pH as independent variables. A combination of low levels of both glucose ({<=}2 g/L) and vitamin solutions ({<=}1 mL/L) and high levels of initial pH ({>=}7), mineral salts solution ({>=}5 mL/L) and FeSO{sub 4} ({>=}100 mg/L) stimulated the hydrogen production, while high level of glucose ({>=}5 g/L) and low levels of both initial pH ({<=}5.5) and mineral salts solution ({<=}1 mL/L) enhanced the ethanol production. High yield of simultaneous hydrogen and ethanol production (1.58 mol H{sub 2}/mol glucose combined with an ethanol yield of 0.90 mol ethanol/mol glucose) was achieved under extreme-thermophilic mixed culture environment. Results obtained showed that the shift of the metabolic pathways favouring either hydrogen or ethanol production was affected by the change in cultivation conditions (pH and medium composition). The mixed culture in this study demonstrated flexible ability for simultaneous hydrogen and ethanol production, depending on pH and nutrients formulation. The microorganisms involved could be regarded as simultaneous hydrogen/ethanol producers, as hydrogen and ethanol fermentation under all conditions was carried out by a group of extreme-thermophilic bacterial species related to Thermoanaerobacter, Thermoanaerobacterium and Caldanaerobacter. (author)

  7. Bubble growth from clustered hydrogen and helium atoms in tungsten under a fusion environment

    Science.gov (United States)

    You, Yu-Wei; Kong, Xiang-Shan; Wu, Xuebang; Liu, C. S.; Chen, J. L.; Luo, G.-N.

    2017-01-01

    Bubbles seriously degrade the mechanical properties of tungsten and thus threaten the safety of nuclear fusion devices, however, the underlying atomic mechanism of bubble growth from clustered hydrogen and helium atoms is still mysterious. In this work, first-principles calculations are therefore carried out to assess the stability of tungsten atoms around both hydrogen and helium clusters. We find that the closest vacancy-formation energies of interstitial hydrogen and helium clusters are substantially decreased. The first-nearest and second-nearest vacancy-formation energies close to vacancy-hydrogen clusters decrease in a step-like way to  ˜0, while those close to vacancy-helium clusters are reduced almost linearly to  ˜-5.46 eV when atom number reaches 10. The vacancy-formation energies closest to helium clusters are more significantly reduced than those nearest to hydrogen clusters, whatever the clusters are embedded at interstitial sites or vacancies. The reduction of vacancy-formation energies results in instability and thus emission of tungsten atoms close to interstitial helium and vacancy-helium clusters, which illustrates the experimental results, that the tungsten atoms can be emitted from the vicinity of vacancy-helium clusters. In addition, the emission of unstable tungsten atoms close to hydrogen clusters may become possible once they are disturbed by the environment. The emission of tungsten atoms facilitates the growth and evolution of hydrogen and helium clusters and ultimately the bubble formation. The results also explain the bubble formation even if no displacement damage is produced in tungsten exposed to low-energy hydrogen and helium plasma.

  8. Computing environment for the ASSIST data warehouse at Lawrence Livermore National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Shuk, K.

    1995-11-01

    The current computing environment for the ASSIST data warehouse at Lawrence Livermore National Laboratory is that of a central server that is accessed by a terminal or terminal emulator. The initiative to move to a client/server environment is strong, backed by desktop machines becoming more and more powerful. The desktop machines can now take on parts of tasks once run entirely on the central server, making the whole environment computationally more efficient as a result. Services are tasks that are repeated throughout the environment such that it makes sense to share them; tasks such as email, user authentication and file transfer are services. The new client/;server environment needs to determine which services must be included in the environment for basic functionality. These services then unify the computing environment, not only for the forthcoming ASSIST+, but for Administrative Information Systems as a whole, joining various server platforms with heterogeneous desktop computing platforms.

  9. Emission estimation of neat paradise tree oil combustion assisted with superheated hydrogen in a 4-stroke natural aspirated DICI engine

    Directory of Open Access Journals (Sweden)

    Sundararajan Karthikayan

    2016-01-01

    Full Text Available This research work investigates the use of neat paradise tree oil in a 4-stroke natural aspirated direct injection compression ignition engine assisted with the help of super-heated hydrogen (hydrogen in gaseous state or above its saturation temperature as a combustion improver. The high calorific gaseous fuel hydrogen gas was used as a combustion improver and admitted into the engine during the suction stroke. A 4-stroke single cylinder Diesel engine was chosen and its operating parameters were suitably modified. Neat paradise tree oil was admitted through standard injector of the engine and hydrogen was admitted through induction manifold. Inducted super-heated hydrogen was initiated the intermediate compounds combustion of neat paradise tree oil. This process offers higher temperature combustion and results in complete combustion of heavier molecules of neat paradise tree oil within shorter duration. The results of the experiment reveal that 40% higher NOx, 20% lower smoke, 5% lower CO, and 45% lower HC than that of neat paradise tree oil fuel operation and the admission of superheated hydrogen has improved the combustion characteristics of neat paradise tree oil. The investigation successfully proved that the application of neat paradise tree oil with 15% of hydrogen improver is possible under a regular Diesel engine with minimal engine modification.

  10. The development of in situ fracture toughness evaluation techniques in hydrogen environment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL; Ren, Fei [ORNL; Tan, Ting [ORNL; Liu, Ken C [ORNL

    2014-01-01

    Fracture behavior and fracture toughness are of great interest regarding reliability of hydrogen pipelines and storage tanks, however, many conventional fracture testing techniques are difficult to be realized under the presence of hydrogen, in addition to the inherited specimen size effect. Thus it is desired to develop novel in situ fracture toughness evaluation techniques to study the fracture behavior of structural materials in hydrogen environments. In this study, a torsional fixture was developed to utilize an emerging fracture testing technique, Spiral Notch Torsion Test (SNTT). The in situ testing results indicated that the exposure to H2 significantly reduces the fracture toughness of 4340 high strength steels by up to 50 percent. Furthermore, SNTT tests conducted in air demonstrated a significant fracture toughness reduction in samples subject to simulated welding heat treatment using Gleeble, which illustrated the effect of welding on the fracture toughness of this material.

  11. Pulsed laser ablation of Germanium under vacuum and hydrogen environments at various fluences

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Hassan [Centre for Advanced Studies in Physics, Government College University, Lahore (Pakistan); Bashir, Shazia, E-mail: shaziabashir@gcu.edu.pk [Centre for Advanced Studies in Physics, Government College University, Lahore (Pakistan); Rafique, Muhammad Shahid [Department of Physics, University of Engineering and Technology, Lahore (Pakistan); Dawood, Asadullah; Akram, Mahreen; Mahmood, Khaliq; Hayat, Asma; Ahmad, Riaz; Hussain, Tousif [Centre for Advanced Studies in Physics, Government College University, Lahore (Pakistan); Mahmood, Arshad [National Institute of Laser and Optronics (NILOP), Islamabad (Pakistan)

    2015-07-30

    Highlights: • Germanium targets were exposed under vacuum and H{sub 2} environment by nanosecond laser pulses. • The effect of laser fluence and ambient environment has been investigated. • The surface morphology is investigated by SEM analysis. • Raman and FTIR Spectroscopy are performed to reveal structural modification. • Electrical conductivity is probed by four probe method. - Abstract: Laser fluence and ambient environment play a significant role for the formation and development of the micro/nano-structures on the laser irradiated targets. Single crystal (1 0 0) Germanium (Ge) has been ablated under two environments of vacuum (10{sup −3} Torr) and hydrogen (100 Torr) at various fluences ranging from 4.5 J cm{sup −2} to 6 J cm{sup −2}. For this purpose KrF Excimer laser with wavelength of 248 nm, pulse duration of 18 ns and repetition rate of 20 Hz has been employed. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets was explored by Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. Electrical conductivity of the irradiated Ge is measured by four probe method. SEM analysis exhibits the formation of laser-induced periodic surface structures (LIPSS), cones and micro-bumps in both ambient environments (vacuum and hydrogen). The formation as well as development of these structures is strongly dependent upon the laser fluence and environmental conditions. The periodicity of LIPSS or ripples varies from 38 μm to 60 μm in case of vacuum whereas in case of hydrogen environment, the periodicity varies from 20 μm to 45 μm. The difference in number of ripples and periodicity as well as in shape and size of cones and bumps in vacuum and hydrogen is explained on the basis of confinement and shielding effect of plasma. FTIR spectroscopy reveals that no new bands are formed for laser ablated Ge under vacuum, whereas C−H stretching vibration band is

  12. Environment-assisted quantum-information correction for continuous variables

    DEFF Research Database (Denmark)

    Sabuncu, Metin; Filip, R.; Leuchs, G.

    2010-01-01

    Quantum-information protocols are inevitably affected by decoherence which is associated with the leakage of quantum information into an environment. In this article we address the possibility of recovering the quantum information from an environmental measurement. We investigate continuous-varia...

  13. Intelligent Assistance for Teachers in Collaborative E-Learning Environments

    Science.gov (United States)

    Casamayor, Agustin; Amandi, Analia; Campo, Marcelo

    2009-01-01

    Collaborative learning environments provide a set of tools for students acting in groups to interact and accomplish an assigned task. In this kind of systems, students are free to express and communicate with each other, which usually lead to collaboration and communication problems that may require the intervention of a teacher. In this article,…

  14. Tensile properties of V-Cr-Ti alloys after exposure in hydrogen-containing environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Soppett, W.K. [Argonne National Lab., IL (United States)

    1998-03-01

    A systematic study has been initiated to evaluate the performance of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with the hydrogen uptake in the samples and its influence on the microstructure and tensile properties of the alloys. At present, four heats of alloys (BL-63, BL-71, and T87, plus 44 from General Atomics) are being evaluated. Other variables of interest are the effect of initial grain size on hydrogen uptake and tensile properties, and the synergistic effects of oxygen and hydrogen on the tensile behavior of the alloys. Experiments conducted thus far on specimens of various V-Cr-Ti alloys exposed to pH{sub 2} levels of 0.01 and 3 {times} 10{sup {minus}6} torr showed negligible effect of H{sub 2} on either maximum engineering stress of uniform/total elongation. Further, preliminary tests on specimens annealed at different temperatures showed that grain size variation by a factor of {approx}2 had a negligible effect on tensile properties.

  15. Chiral Hydrogen Bond Environment Providing Unidirectional Rotation in Photoactive Molecular Motors.

    Science.gov (United States)

    García-Iriepa, Cristina; Marazzi, Marco; Zapata, Felipe; Valentini, Alessio; Sampedro, Diego; Frutos, Luis Manuel

    2013-05-02

    Generation of a chiral hydrogen bond environment in efficient molecular photoswitches is proposed as a novel strategy for the design of photoactive molecular motors. Here, the following strategy is used to design a retinal-based motor presenting singular properties: (i) a single excitation wavelength is needed to complete the unidirectional rotation process (360°); (ii) the absence of any thermal step permits the process to take place at low temperatures; and (iii) the ultrafast process permits high rotational frequencies.

  16. Growth mode transitions induced by hydrogen-assisted MBE on vicinal GaAs(110)

    Energy Technology Data Exchange (ETDEWEB)

    Tejedor, P. [Instituto de Ciencia de Materiales de Madrid (C.S.I.C)., Sor Juana Ines de la Cruz s/n, Cantoblanco, 28049 Madrid (Spain)]. E-mail: ptejedor@icmm.csic.es; Crespillo, M.L. [Instituto de Ciencia de Materiales de Madrid (C.S.I.C)., Sor Juana Ines de la Cruz s/n, Cantoblanco, 28049 Madrid (Spain); Joyce, B.A. [Imperial College of Science, Technology and Medicine, The Blackett Laboratory, London SW7 2BZ (United Kingdom)

    2006-07-15

    The homoepitaxial growth of GaAs by hydrogen-assisted molecular beam epitaxy (H-MBE) on (110) substrates vicinal to (111)A has been studied by reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM) for different kinetic regimes. When the GaAs growth rate is limited by the kinetics of adatom incorporation to steps, the presence of chemisorbed H on the surface after oxide removal promotes the incorporation of adatoms to steps from the lower terraces, leading to the formation of multiatomic step arrays or ridge patterns by a combination of step propagation and two-dimensional layer-by-layer growth. Supply of atomic H during epitaxy favours three-dimensional growth, leading to Ga-induced surface roughening or mound formation. At high temperatures, the Ga-As interactions at step edges are faster and stable growth of GaAs occurs by step propagation, leading to a faceted surface when H is used both during oxide removal and/or MBE growth.

  17. Pulsed laser ablation of Germanium under vacuum and hydrogen environments at various fluences

    Science.gov (United States)

    Iqbal, Muhammad Hassan; Bashir, Shazia; Rafique, Muhammad Shahid; Dawood, Asadullah; Akram, Mahreen; Mahmood, Khaliq; Hayat, Asma; Ahmad, Riaz; Hussain, Tousif; Mahmood, Arshad

    2015-07-01

    Laser fluence and ambient environment play a significant role for the formation and development of the micro/nano-structures on the laser irradiated targets. Single crystal (1 0 0) Germanium (Ge) has been ablated under two environments of vacuum (10-3 Torr) and hydrogen (100 Torr) at various fluences ranging from 4.5 J cm-2 to 6 J cm-2. For this purpose KrF Excimer laser with wavelength of 248 nm, pulse duration of 18 ns and repetition rate of 20 Hz has been employed. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets was explored by Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. Electrical conductivity of the irradiated Ge is measured by four probe method. SEM analysis exhibits the formation of laser-induced periodic surface structures (LIPSS), cones and micro-bumps in both ambient environments (vacuum and hydrogen). The formation as well as development of these structures is strongly dependent upon the laser fluence and environmental conditions. The periodicity of LIPSS or ripples varies from 38 μm to 60 μm in case of vacuum whereas in case of hydrogen environment, the periodicity varies from 20 μm to 45 μm. The difference in number of ripples and periodicity as well as in shape and size of cones and bumps in vacuum and hydrogen is explained on the basis of confinement and shielding effect of plasma. FTIR spectroscopy reveals that no new bands are formed for laser ablated Ge under vacuum, whereas Csbnd H stretching vibration band is formed for two moderate fluences (5 J cm-2 and 5.5 J cm-2) in case of ablation in hydrogen. Raman spectroscopy shows that no new bands are formed in case of ablation in both environments; however a slight Raman shift is observed which is attributed to laser-induced stresses. The electrical conductivity of the irradiated Ge increases with increasing fluence and is also dependent upon the environment as well as grown structures.

  18. Identifying the Potential for Robotics to Assist Older Adults in Different Living Environments

    OpenAIRE

    2013-01-01

    As the older adult population grows and becomes more diverse, so will their needs and preferences for living environments. Many adults over 65 years of age require some assistance [1, 2]; yet it is important for their feelings of well-being that the assistance not restrict their autonomy [3]. Not only is autonomy correlated with quality of life [4], autonomy enhancement may improve functionality [2, 5]. The goal of this paper is to provide guidance for the development of technology to enhance...

  19. Power assist control of electric bicycle taking environment and rider's condition into account

    Science.gov (United States)

    Niki, Hiroshi; Miyata, Junichi; Murakami, Toshiyuki

    2005-12-01

    Recently, bicycles are widely used as a convenient transportation tool. But from a viewpoint of wide use for the future aging society, it is problem to pedal on rider's own. As well known, power assistance bicycle has already been used. The power assistance bicycle helps the elderly people or the people who has weak legs to expand their field. However, existing power assistance bicycle doesn't take running environment and rider's condition into account. The new control algorithm for power assistance bicycle is proposed in this paper. Human input and running friction are estimated as a disturbance torque with a disturbance observer. By using high pass filter (HPF), human input is separated from running friction. This method realizes power assistance bicycle without torque sensor. Disturbance observer compensates running friction. Compliance control is applied to make the bicycle have desired compliance. The effectiveness of this control algorithm is verified by numerical and experimental results.

  20. Moles: Tool-Assisted Environment Isolation with Closures

    Science.gov (United States)

    de Halleux, Jonathan; Tillmann, Nikolai

    Isolating test cases from environment dependencies is often desirable, as it increases test reliability and reduces test execution time. However, code that calls non-virtual methods or consumes sealed classes is often impossible to test in isolation. Moles is a new lightweight framework which addresses this problem. For any .NET method, Moles allows test-code to provide alternative implementations, given as .NET delegates, for which C# provides very concise syntax while capturing local variables in a closure object. Using code instrumentation, the Moles framework will redirect calls to provided delegates instead of the original methods. The Moles framework is designed to work together with the dynamic symbolic execution tool Pex to enable automated test generation. In a case study, testing code programmed against the Microsoft SharePoint Foundation API, we achieved full code coverage while running tests in isolation without an actual SharePoint server. The Moles framework integrates with .NET and Visual Studio.

  1. Environment-assisted quantum transport and trapping in dimers

    CERN Document Server

    Muelken, Oliver

    2010-01-01

    We study the dynamics and trapping of excitations for a dimer with an energy off-set $\\Delta$ coupled to an external environment. Using a Lindblad quantum master equation approach, we calculate the survival probability $\\Pi(t)$ of the excitation and define different lifetimes $\\tau_s$ of the excitation, corresponding to the duration of the decay of $\\Pi(t)$ in between two predefined values. We show that it is not possible to always enhance the overall decay to the trap. However, it is possible, even for not too small environmental couplings and for values of $\\Delta$ of the order ${\\cal O}(1)$, to decrease certain lifetimes $\\tau_s$, leading to faster decay of $\\Pi(t)$ in these time intervals: There is an optimal environmental coupling, leading to a maximal decay for fixed $\\Delta$.

  2. Thermophilic hydrogen-producing bacteria inhabiting deep-sea hydrothermal environments represented by Caloranaerobacter.

    Science.gov (United States)

    Jiang, Lijing; Xu, Hongxiu; Zeng, Xiang; Wu, Xiaobing; Long, Minnan; Shao, Zongze

    2015-11-01

    Hydrogen is an important energy source for deep-sea hydrothermal vent ecosystems. However, little is known about microbes and their role in hydrogen turnover in the environment. In this study, the diversity and physiological characteristics of fermentative hydrogen-producing microbes from deep-sea hydrothermal vent fields were described for the first time. Seven enrichments were obtained from hydrothermal vent sulfides collected from the Southwest Indian Ocean, East Pacific and South Atlantic. 16S rRNA gene analysis revealed that members of the Caloranaerobacter genus were the dominant component in these enrichments. Subsequently, three thermophilic hydrogen producers, strains H363, H53214 and DY22619, were isolated. They were phylogenetically related to species of the genus Caloranaerobacter. The H2 yields of strains H363, H53214, DY22619 and MV107, which was the type species of genus Caloranaerobacter, were 0.11, 1.21, 3.13 and 2.85 mol H2/mol glucose, respectively. Determination of the main soluble metabolites revealed that strains H363, H53214 and MV107 performed heterolactic fermentations, while strain DY22619 performed butyric acid fermentation, indicating distinct fermentation patterns among members of the genus. Finally, a diversity of forms of [FeFe]-hydrogenase with different modular structures was revealed based on draft genomic data of Caloranaerobacter strains. This highlights the complexity of hydrogen metabolism in Caloranaerobacter, reflecting adaptations to environmental conditions in hydrothermal vent systems. Collectively, results suggested that Caloranaerobacter species might be ubiquitous and play a role in biological hydrogen generation in deep-sea hydrothermal vent fields.

  3. Energy decomposition analysis of cation-π, metal ion-lone pair, hydrogen bonded, charge-assisted hydrogen bonded, and π-π interactions.

    Science.gov (United States)

    Sharma, Bhaskar; Srivastava, Hemant Kumar; Gayatri, Gaddamanugu; Sastry, Garikapati Narahari

    2015-03-30

    This study probes the nature of noncovalent interactions, such as cation-π, metal ion-lone pair (M-LP), hydrogen bonding (HB), charge-assisted hydrogen bonding (CAHB), and π-π interactions, using energy decomposition schemes-density functional theory (DFT)-symmetry-adapted perturbation theory and reduced variational space. Among cation-π complexes, the polarization and electrostatic components are the major contributors to the interaction energy (IE) for metal ion-π complexes, while for onium ion-π complexes (NH4+, PH4+, OH3+, and SH3+) the dispersion component is prominent. For M-LP complexes, the electrostatic component contributes more to the IE except the dicationic metal ion complexes with H2 S and PH3 where the polarization component dominates. Although electrostatic component dominates for the HB and CAHB complexes, dispersion is predominant in π-π complexes.

  4. Microwave-assisted modulated synthesis of zirconium-based metal-organic framework (Zr-MOF) for hydrogen storage applications

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Jianwei; Segakweng, Tshiamo; Langmi, Henrietta W.; Musyoka, Nicholas M.; North, Brian C.; Mathe, Mkhulu [Council for Scientific and Industrial Research (CSIR), Pretoria (South Africa). HySA Infrastructure Centre of Competence, Materials Science and Manufacturing; Bessarabov, Dmitri [North-West Univ. (NWU), Potchefstroom (South Africa). HySA Infrastructure Centre of Competence

    2014-05-15

    Zirconium-based metal-organic framework (Zr-MOF) was synthesized using a microwave-assisted modulated method in a short reaction time of 5 min. The Zr-MOF material was highly crystalline with well-defined octahedral shaped crystals, and it exhibited comparable hydrogen storage capacity to Zr-MOF of similar specific surface area synthesized using conventional methods with much longer synthesis time. (orig.)

  5. Numerical Simulation of Hydrogen Assisted Cracking in Supermartensitic Stainless Steel Welds

    Science.gov (United States)

    2005-01-27

    M.F.Stevens and I.M.Bernstein: "Microstructural Trapping Effects on Hydrogen Induced Cracking of a Microalloyed Steel", Metallurgical Transactions A...Electrolytic Hydrogen in Palladium ", pp.9 0 - 102. [HPD 68] Th.Boellinghaus and E.Viyanit: "Revised Scatterbands for Hydrogen Diffusion Coefficients

  6. Separation of gaseous hydrogen from a water-hydrogen mixture in a fuel cell power system operating in a weightless environment

    Science.gov (United States)

    Romanowski, William E. (Inventor); Suljak, George T. (Inventor)

    1989-01-01

    A fuel cell power system for use in a weightless environment, such as in space, includes a device for removing water from a water-hydrogen mixture condensed from the exhaust from the fuel cell power section of the system. Water is removed from the mixture in a centrifugal separator, and is fed into a holding, pressure operated water discharge valve via a Pitot tube. Entrained nondissolved hydrogen is removed from the Pitot tube by a bleed orifice in the Pitot tube before the water reaches the water discharge valve. Water discharged from the valve thus has a substantially reduced hydrogen content.

  7. Modeling Hydrogen-Induced Cracking of Titanium Alloys in Nuclear Waste Repository Environments

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-09-08

    This paper reviews the current understanding of hydrogen-induced cracking (HIC) of Ti Grade 7 and other relevant titanium alloys within the context of the current waste package design for the repository environmental conditions anticipated within the Yucca Mountain repository. The review concentrates on corrosion processes possible in the aqueous environments expected within this site. A brief background discussion of the relevant properties of titanium alloys, the hydrogen absorption process, and the properties of passive film on titanium alloys is presented as the basis for the subsequent discussion of model developments. The key corrosion processes that could occur are addressed individually. Subsequently, the expected corrosion performance of these alloys under the specific environmental conditions anticipated at Yucca Mountain is considered. It can be concluded that, based on the conservative modeling approaches adopted, hydrogen-induced cracking of titanium alloys will not occur under nuclear waste repository conditions since there will not be sufficient hydrogen in the alloy after 10,000 years of emplacement.

  8. Birth environment facilitation by midwives assisting in non-hospital births: a qualitative interview study.

    Science.gov (United States)

    Igarashi, Toshiko; Wakita, Mariko; Miyazaki, Kikuko; Nakayama, Takeo

    2014-07-01

    midwifery homes (similar to birth centres) are rich in midwifery wisdom and skills that differ from those in hospital obstetrical departments, and a certain percentage of pregnant women prefer birth in these settings. This study aimed to understand the organisation of the perinatal environment considered important by independent midwives in non-hospital settings and to clarify the processes involved. semi-structured qualitative interview study and constant comparative analysis. 14 independent midwives assisting at births in midwifery homes in Japan, and six independent midwives assisting at home births. Osaka, Kyoto, Nara, and Shiga, Japan. midwives assisting at non-hospital births organised the birth environment based on the following four categories: 'an environment where the mother and family are autonomous'; 'a physical environment that facilitates birth'; 'an environment that facilitates the movement of the mother for birth'; and 'scrupulous safety preparation'. These, along with their sub-categories, are presented in this paper. independent midwives considered it important to create a candid relationship between the midwife and the woman/family from the period of pregnancy to facilitate birth in which the woman and her family were autonomous. They also organised a distinctive environment for non-hospital birth, with preparations to guarantee safety. Experiential knowledge and skills played a major part in creating an environment to facilitate birth, and the effectiveness of this needs to be investigated objectively in future research. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Environment-Assisted Speed-up of the Field Evolution in Cavity Quantum Electrodynamics.

    Science.gov (United States)

    Cimmarusti, A D; Yan, Z; Patterson, B D; Corcos, L P; Orozco, L A; Deffner, S

    2015-06-12

    We measure the quantum speed of the state evolution of the field in a weakly driven optical cavity QED system. To this end, the mode of the electromagnetic field is considered as a quantum system of interest with a preferential coupling to a tunable environment: the atoms. By controlling the environment, i.e., changing the number of atoms coupled to the optical cavity mode, an environment-assisted speed-up is realized: the quantum speed of the state repopulation in the optical cavity increases with the coupling strength between the optical cavity mode and this non-Markovian environment (the number of atoms).

  10. Session 4: HDS, HDN and HYD assisted by ultrasound using formic acid as hydrogen precursor

    Energy Technology Data Exchange (ETDEWEB)

    Scott Carlos, E.; Bolivar, C.; Grobas, J. [Universidad Central de Venezuela, Centro de Catalisis Petroleo y Petroquimica, Escuela de Quimica, Facultad de Ciencias, Caracas (Venezuela)

    2004-07-01

    The study of chemical effects of ultrasound is a rapidly growing research area, and its use in heavy crude oil upgrading has been explored. In this work, hydrogenation of cyclohexene and biphenyl, hydrodesulfurization of benzothiophene and hydro-denitrogenation of quinoline, in the presence of a hydrogen precursor, a Pd/C catalyst and ultrasound irradiation was studied. It was found, that the use of formic acid as hydrogen precursor in presence of ultrasonic irradiation was an effective system to promote hydrogenation of cyclohexene (98%) and biphenyl (21%), desulfurization of benzothiophene (18%) and hydrogenation of quinoline (19%), at very mild conditions, i.e. ambient temperature and pressure. (authors)

  11. Origin of the smaller conductances of Rh, Pb, and Co atomic junctions in hydrogen environment

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xue; Chen, Mingyan; Ye, Xiang; Xie, Yi-qun, E-mail: yqxie@shnu.edu.cn [Department of Physics, Shanghai Normal University, 100 Guilin Road, Shanghai 200232 (China); Ke, San-huang, E-mail: shke@tongji.edu.cn [MOE Key Laboratory of Advanced Microstructured Materials, School of Physics Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

    2015-02-14

    We study theoretically the structural and electronic origins of the smaller conductances (one conductance quantum, G{sub 0}, and smaller) of Rh, Pb, and Co metal atomic junctions (MAJs) in a hydrogen environment, as were measured in recent experiments. For the Rh MAJs, the 1G{sub 0} conductance is attributed to a stable contact bridged by a single hydrogen molecule whose antibonding state provides a single transport channel. For the Pb and Co MAJs the 1G{sub 0} conductance is, however, ascribed to a linear atomic chain adsorbing two dissociated H atoms, which largely reduces the density of states at the Fermi energy with respect to the pure ones. On the other hand, the small conductances of 0.3G{sub 0} (Rh) and 0.2G{sub 0} (Co) are due to H-decorated atomic chains connected to electrodes by a H atom.

  12. Cooperative effect of hydrogen-bonded chains in the environment of a pi --> pi* chromophore.

    Science.gov (United States)

    Fradelos, Georgios; Kaminski, Jakub W; Wesolowski, Tomasz A; Leutwyler, Samuel

    2009-09-10

    Laser resonant two-photon ionization UV spectra provide clear evidence that the effect of increasing the length of the hydrogen-bonded chain consisting of molecules such as NH(3), H(2)O, or CH(3)OH on the pi --> pi* excitations of cis-7-hydroxyquinoline (cis-7HQ) is strongly cooperative [ Thut ; et al. J. Phys. Chem. A 2008 , 112 , 5566. ] A theoretical analysis of the experimental data is provided to identify the origin of this cooperativity for four chains. The computational method to determine the changes of the electronic structure of a molecule due to interactions with its environment uses the nonempirical expression for the embedding potential [ Wesolowski ; Warshel J. Phys. Chem. 1993 , 97 , 8050. ] It is concluded that the electronic coupling between the molecules at the ends of the chain, which are hydrogen-bonded to cis-7HQ, plays a crucial role in this cooperativity.

  13. Effects of a Hydrogen Gas Environment on Fatigue Crack Growth of a Stable Austenitic Stainless Steel

    Science.gov (United States)

    Kawamoto, Kyohei; Oda, Yasuji; Noguchi, Hiroshi; Higashida, Kenji

    In order to clarify the effects of a hydrogen gas environment on the fatigue crack growth characteristics of stable austenitic stainless steels, bending fatigue tests were carried out in a hydrogen gas, in a nitrogen gas at 1.0 MPa and in air on a SUS316L using the Japanese Industrial Standards (type 316L). Also, in order to discuss the difference in the hydrogen sensitivity between austenitic stainless steels, the fatigue tests were also carried out on a SUS304 using the Japanese Industrial Standards (type 304) metastable austenitic stainless steel as a material for comparison. The main results obtained are as follows. Hydrogen gas accelerates the fatigue crack growth rate of type 316L. The degree of the fatigue crack growth acceleration is low compared to that in type 304. The fracture surfaces of both the materials practically consist of two parts; the faceted area seemed to be brittle and the remaining area occupying a greater part of the fracture surface and seemed to be ductile. The faceted area does not significantly contribute to the fatigue crack growth rate in both austenitic stainless steels. The slip-off mechanism seems to be valid not only in air and in nitrogen, but also in hydrogen. Also, the main cause of the fatigue crack growth acceleration of both materials occurs by variation of the slip behaviour. The difference in the degree of the acceleration, which in type 316L is lower than in type 304, seems to be caused by the difference in the stability of the γ phase.

  14. Fiber Bragg gratings in the radiation environment: Change under the influence of radiolytic hydrogen

    Science.gov (United States)

    Butov, Oleg V.; Golant, Konstantin M.; Shevtsov, Igor'A.; Fedorov, Artem N.

    2015-08-01

    The change of the transmission spectra of fiber Bragg gratings written in the optical fibers, whose silica cores are doped with either germanium or nitrogen, is studied experimentally under the influence of gamma-radiation. The transmission spectra in the neighborhood of the resonance (Bragg) wavelengths were regularly recorded "in-situ" in the course of irradiation during 24 days. For this purpose, uncoated gratings were placed in a pool near the spent fuel rods of a nuclear reactor. The fibers with the gratings written in them were in immediate contact with water. The estimated total absorbed radiation dose of the fibers is approximately 5 MGy. Molecular hydrogen, which is produced by radiolysis of water and penetrates into the core of silica fiber, is found to interact with the defects of Ge-doped silica induced by gamma-radiation, thereby causing a strong impact on the parameters of the spectrum of the Bragg gratings. On the contrary, in the case of gratings inscribed in N-doped silica fibers, the hydrogen molecules interact with defects induced in the course of laser UV exposure during the grating writing only. The possible subsequent formation of additional defects in N-doped silica under the influence of gamma-radiation has no substantial impact on the transmission spectra of Bragg gratings, which remained stable. The obtained results suggest that a small amount of molecular hydrogen resided in the fiber core is the main source of radiation instability of Ge-doped fiber Bragg grating sensors in radiation environments. These hydrogen molecules can remain in the Bragg gratings, in particular, after the inscription process in the hydrogen-loaded fibers.

  15. Fiber Bragg gratings in the radiation environment: Change under the influence of radiolytic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Butov, Oleg V., E-mail: obutov@mail.ru; Golant, Konstantin M. [Kotel' nikov Institute of Radio-Engineering and Electronics of RAS, 11-7 Mokhovaya Str., Moscow 125009 (Russian Federation); Shevtsov, Igor' A.; Fedorov, Artem N. [Prolog LLC, PO Box 3007, Obninsk, the Kaluga Region 249033 (Russian Federation)

    2015-08-21

    The change of the transmission spectra of fiber Bragg gratings written in the optical fibers, whose silica cores are doped with either germanium or nitrogen, is studied experimentally under the influence of gamma-radiation. The transmission spectra in the neighborhood of the resonance (Bragg) wavelengths were regularly recorded “in-situ” in the course of irradiation during 24 days. For this purpose, uncoated gratings were placed in a pool near the spent fuel rods of a nuclear reactor. The fibers with the gratings written in them were in immediate contact with water. The estimated total absorbed radiation dose of the fibers is approximately 5 MGy. Molecular hydrogen, which is produced by radiolysis of water and penetrates into the core of silica fiber, is found to interact with the defects of Ge-doped silica induced by gamma-radiation, thereby causing a strong impact on the parameters of the spectrum of the Bragg gratings. On the contrary, in the case of gratings inscribed in N-doped silica fibers, the hydrogen molecules interact with defects induced in the course of laser UV exposure during the grating writing only. The possible subsequent formation of additional defects in N-doped silica under the influence of gamma-radiation has no substantial impact on the transmission spectra of Bragg gratings, which remained stable. The obtained results suggest that a small amount of molecular hydrogen resided in the fiber core is the main source of radiation instability of Ge-doped fiber Bragg grating sensors in radiation environments. These hydrogen molecules can remain in the Bragg gratings, in particular, after the inscription process in the hydrogen-loaded fibers.

  16. The relationship of positive work environments and workplace injury: evidence from the National Nursing Assistant Survey.

    Science.gov (United States)

    McCaughey, Deirdre; McGhan, Gwen; Walsh, Erin M; Rathert, Cheryl; Belue, Rhonda

    2014-01-01

    With estimates of a 51% growth in the number of nursing assistants needed by 2016, there is a critical need to examine workplace factors that negatively contribute to the recruitment and retention of nursing assistants. Studies have shown that high demands, physical stress, and chronic workforce shortages contribute to a working environment that fosters one of the highest workforce injury rates in the United States. The aim of this study was to explore the relationship between nursing assistant injury rates and key outcomes, such as job satisfaction and turnover intent, while exploring workplace environment factors, such as injury prevention training, supervisor support, and employee engagement, that can decrease the rates of workplace injury. Data from the 2004 National Nursing Assistant Survey were used to examine the negative effects of workplace injury on nursing assistants and the workplace environment factors that are related to the rate of worker injury. Nursing assistants who experience job-related injuries have lower levels of job satisfaction, increased turnover intentions, and are less likely to recommend their facility as a place to work or seek care services. It was also found that nursing assistant injury rates are related to employee ratings of injury prevention training, supervisor support, and employee engagement. NAs with multiple injuries (>2) were 1.3-1.6 times more likely to report being injured at work than NAs who had not been injured when supervisor support, employee engagement, and training ratings were low. Evidence that health care organizations can use to better understand how workplace injuries occur and insight into ways to reduce the current staggering rate of on-the-job injuries occurring in health care workplaces were offered in this study. The findings also offer empirical support for an extension of the National Institute for Occupational Health and Safety/National Occupational Research Agenda Work Organization Framework for

  17. Secondary School Students' Attitudes towards Mathematics Computer--Assisted Instruction Environment in Kenya

    Science.gov (United States)

    Mwei, Philip K.; Wando, Dave; Too, Jackson K.

    2012-01-01

    This paper reports the results of research conducted in six classes (Form IV) with 205 students with a sample of 94 respondents. Data represent students' statements that describe (a) the role of Mathematics teachers in a computer-assisted instruction (CAI) environment and (b) effectiveness of CAI in Mathematics instruction. The results indicated…

  18. Learning Tools for Knowledge Nomads: Using Personal Digital Assistants (PDAs) in Web-based Learning Environments.

    Science.gov (United States)

    Loh, Christian Sebastian

    2001-01-01

    Examines how mobile computers, or personal digital assistants (PDAs), can be used in a Web-based learning environment. Topics include wireless networks on college campuses; online learning; Web-based learning technologies; synchronous and asynchronous communication via the Web; content resources; Web connections; and collaborative learning. (LRW)

  19. Hydrogen.

    Science.gov (United States)

    Bockris, John O'M

    2011-11-30

    The idea of a "Hydrogen Economy" is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO₂ in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H₂ from the electrolyzer. Methanol made with CO₂ from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan). Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs) by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  20. Sulfide stress corrosion study of a super martensitic stainless steel in H2S sour environments: Metallic sulfides formation and hydrogen embrittlement

    Science.gov (United States)

    Monnot, Martin; Nogueira, Ricardo P.; Roche, Virginie; Berthomé, Grégory; Chauveau, Eric; Estevez, Rafael; Mantel, Marc

    2017-02-01

    Thanks to their high corrosion resistance, super martensitic stainless steels are commonly used in the oil and gas industry, particularly in sour environments. Some grades are however susceptible to undergo hydrogen and mechanically-assisted corrosion processes in the presence of H2S, depending on the pH. The martensitic stainless steel EN 1.4418 grade exhibits a clear protective passive behavior with no sulfide stress corrosion cracking when exposed to sour environments of pH ≥ 4, but undergoes a steep decrease in its corrosion resistance at lower pH conditions. The present paper investigated this abrupt loss of corrosion resistance with electrochemical measurements as well as different physicochemical characterization techniques. Results indicated that below pH 4.0 the metal surface is covered by a thick (ca 40 μm) porous and defect-full sulfide-rich corrosion products layer shown to be straightforwardly related to the onset of hydrogen and sulfide mechanically-assisted corrosion phenomena.

  1. Origin of the periodic structure in the conductance curve of gold nanojunctions in hydrogen environment

    Science.gov (United States)

    Jiang, Zhuoling; Wang, Hao; Sanvito, Stefano; Hou, Shimin

    2016-03-01

    The evolution of the atomic structure and the vibrational and electronic transport properties of gold atomic junctions incorporating molecular and atomic hydrogen upon elongation have been investigated with the nonequilibrium Green's function formalism combined with density functional theory. Our calculations show that for the case of gold junctions doped with a single H2 molecule the low-bias conductance drops rapidly with the electrodes' separation, while it remains almost constant if a single H atom replaces the molecule. In contrast, when one considers two H atoms adsorbed on a gold monatomic chain forming an Au-H-Au-H-Au double-bridge structure, the low-bias conductance increases first and then shows a plateau upon stretching the junction, in perfect agreement with experiments on gold nanocontacts in hydrogen environment. Furthermore, also the distribution of the calculated vibrational energies of the two H atoms is consistent with the experimental result in the low-conductance region, demonstrating clear evidence that hydrogen molecules can dissociate on stretched gold monatomic chains. These findings are helpful to improve our understanding of the structure-property relation of gold nanocontacts and also provide a new prospect for gold nanowires being used as chemical sensors and catalysts.

  2. Assisted Tandem Catalysis : Metathesis Followed by Asymmetric Hydrogenation from a Single Ruthenium Source

    NARCIS (Netherlands)

    Renom-Carrasco, Marc; Gajewski, Piotr; Pignataro, Luca; de Vries, Johannes G.; Piarulli, Umberto; Gennari, Cesare; Lefort, Laurent

    2015-01-01

    Here we report the first example of a tandem metathesis-asymmetric hydrogenation protocol where the prochiral olefin generated by metathesis is hydrogenated with high enantioselectivity by an in situ formed chiral ruthenium catalyst. We show that either the ruthenium metathesis catalysts or the ruth

  3. Electricity-Assisted Biological Hydrogen Production from Acetate by Geobacter sulfurreducens

    NARCIS (Netherlands)

    Geelhoed, J.S.; Stams, A.J.M.

    2011-01-01

    Geobacter sulfurreducens is a well-known current-producing microorganism in microbial fuel cells, and is able to use acetate and hydrogen as electron donor. We studied the functionality of G. sulfurreducens as biocatalyst for hydrogen formation at the cathode of a microbial electrolysis cell (MEC).

  4. [Electrochemically active microorganisms and electrolytically assisted fermentative hydrogen production--a review].

    Science.gov (United States)

    Li, Jianchang; Zhang, Wudi; Yin, Fang; Xu, Rui; Chen, Yubao

    2009-06-01

    Fermentative hydrogen production can be improved by electrolysis and electrochemically active microorganisms which are capable of using an electrode as an electron acceptor for the oxidation of organic matter, in particular, volatile acids produced after fermentation. Firstly volatile acids can be completely converted into CO2, electrons and protons on the surface of anode. Then the electrons flow to cathode through anode and wires, and at the same time the protons move to cathode through cation membrane between anode chamber and cathode chamber. Finally the electrons and the protons combine into hydrogen when they meet at the surface of cathode. In such a process, the fermentation barrier and the product inhibition can be avoided to improve the conversion of hydrogen. 8-9 mol H2/mol glucose of hydrogen potential can be obtained when glucose is used as substrate. This technology is very likely to be applied to produce hydrogen high efficiently from any energy crops, organic waste and wastewater.

  5. Tensile properties of V-Cr-Ti alloys after exposure in hydrogen-containing environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Soppet, W.K. [Argonne National Lab., IL (United States)

    1998-09-01

    A systematic study has been initiated at Argonne National Laboratory to evaluate the performance of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with hydrogen uptake in the samples and its influence on the microstructure and tensile properties of the alloys. At present, the principal effort has focused on the V-4Cr-4Ti alloy of heat identified as BL-71; however other alloys (V-5Cr-5Ti alloy of heats BL-63, and T87, plus V-4Cr-4Ti alloy from General Atomics [GA]) are also being evaluated. Other variables of interest are the effect of initial grain size on the tensile behavior of the alloys. Experiments conducted on specimens of various V-Cr-Ti alloys exposed to pH{sub 2} levels of 0.01 and 3 {times} 10{sup {minus}6} torr showed negligible effect of H{sub 2} on either maximum engineering stress or uniform and total elongation. However, uniform and total elongation decreased substantially when the alloys were exposed to 1.0 torr H{sub 2} pressure. Preliminary data from sequential exposures of the materials to low-pO{sub 2} and several low-pH{sub 2} environments did not reveal an adverse effect on the maximum engineering stress or on uniform and total elongation. Further, tests in H{sub 2} environments on specimens annealed at different temperatures showed that grain-size variation by a factor of {approx}2 had little or no effect on tensile properties.

  6. Reaction time for processing visual stimulus in a computer-assisted rehabilitation environment.

    Science.gov (United States)

    Sanchez, Yerly; Pinzon, David; Zheng, Bin

    2017-10-01

    To examine the reaction time when human subjects process information presented in the visual channel under both a direct vision and a virtual rehabilitation environment when walking was performed. Visual stimulus included eight math problems displayed on the peripheral vision to seven healthy human subjects in a virtual rehabilitation training (computer-assisted rehabilitation environment (CAREN)) and a direct vision environment. Subjects were required to verbally report the results of these math calculations in a short period of time. Reaction time measured by Tobii Eye tracker and calculation accuracy were recorded and compared between the direct vision and virtual rehabilitation environment. Performance outcomes measured for both groups included reaction time, reading time, answering time and the verbal answer score. A significant difference between the groups was only found for the reaction time (p = .004). Participants had more difficulty recognizing the first equation of the virtual environment. Participants reaction time was faster in the direct vision environment. This reaction time delay should be kept in mind when designing skill training scenarios in virtual environments. This was a pilot project to a series of studies assessing cognition ability of stroke patients who are undertaking a rehabilitation program with a virtual training environment. Implications for rehabilitation Eye tracking is a reliable tool that can be employed in rehabilitation virtual environments. Reaction time changes between direct vision and virtual environment.

  7. RESTful Discovery and Eventing for Service Provisioning in Assisted Living Environments

    Directory of Open Access Journals (Sweden)

    Jorge Parra

    2014-05-01

    Full Text Available Service provisioning in assisted living environments faces distinct challenges due to the heterogeneity of networks, access technology, and sensing/actuation devices in such an environment. Existing solutions, such as SOAP-based web services, can interconnect heterogeneous devices and services, and can be published, discovered and invoked dynamically. However, it is considered heavier than what is required in the smart environment-like context and hence suffers from performance degradation. Alternatively, REpresentational State Transfer (REST has gained much attention from the community and is considered as a lighter and cleaner technology compared to the SOAP-based web services. Since it is simple to publish and use a RESTful web service, more and more service providers are moving toward REST-based solutions, which promote a resource-centric conceptualization as opposed to a service-centric conceptualization. Despite such benefits of REST, the dynamic discovery and eventing of RESTful services are yet considered a major hurdle to utilization of the full potential of REST-based approaches. In this paper, we address this issue, by providing a RESTful discovery and eventing specification and demonstrate it in an assisted living healthcare scenario. We envisage that through this approach, the service provisioning in ambient assisted living or other smart environment settings will be more efficient, timely, and less resource-intensive.

  8. RESTful discovery and eventing for service provisioning in assisted living environments.

    Science.gov (United States)

    Parra, Jorge; Hossain, M Anwar; Uribarren, Aitor; Jacob, Eduardo

    2014-05-23

    Service provisioning in assisted living environments faces distinct challenges due to the heterogeneity of networks, access technology, and sensing/actuation devices in such an environment. Existing solutions, such as SOAP-based web services, can interconnect heterogeneous devices and services, and can be published, discovered and invoked dynamically. However, it is considered heavier than what is required in the smart environment-like context and hence suffers from performance degradation. Alternatively, REpresentational State Transfer (REST) has gained much attention from the community and is considered as a lighter and cleaner technology compared to the SOAP-based web services. Since it is simple to publish and use a RESTful web service, more and more service providers are moving toward REST-based solutions, which promote a resource-centric conceptualization as opposed to a service-centric conceptualization. Despite such benefits of REST, the dynamic discovery and eventing of RESTful services are yet considered a major hurdle to utilization of the full potential of REST-based approaches. In this paper, we address this issue, by providing a RESTful discovery and eventing specification and demonstrate it in an assisted living healthcare scenario. We envisage that through this approach, the service provisioning in ambient assisted living or other smart environment settings will be more efficient, timely, and less resource-intensive.

  9. Hydrogen

    Directory of Open Access Journals (Sweden)

    John O’M. Bockris

    2011-11-01

    Full Text Available The idea of a “Hydrogen Economy” is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO2 in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H2 from the electrolyzer. Methanol made with CO2 from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan. Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  10. Polarization Effects in Two-Photon Free-Free Transitions in Laser-Assisted Electron-Hydrogen Collisions

    CERN Document Server

    Cionga, Aurelia

    2013-01-01

    Two-photon free-free transitions in elastic laser-assisted electron-hydrogen collisions are studied in the domain of high scattering energies and low or moderate field intensities, in the third order of perturbation theory, taking into account all the involved Feynman diagrams. Based on the analytical expressions of the transition amplitudes, the differential cross sections for two-photon absorption/emission are computed at impact energy $E_i=100$ eV. The effect of field polarizations on the angular distribution and on the frequency dependence of the differential cross section is analyzed.

  11. Determination of Hydrogen Bond Structure in Water versus Aprotic Environments To Test the Relationship Between Length and Stability

    Energy Technology Data Exchange (ETDEWEB)

    Sigala, Paul A.; Ruben, Eliza A.; Liu, Corey W.; Piccoli, Paula M. B.; Hohenstein, Edward G.; Martinez, Todd J.; Schultz, Arthur J.; Herschiag, Daniel

    2015-05-06

    Hydrogen bonds profoundly influence the architecture and activity of biological macromolecules. Deep appreciation of hydrogen bond contributions to biomolecular function thus requires a detailed understanding of hydrogen bond structure and energetics and the relationship between these properties. Hydrogen bond formation energies (Delta G(f)) are enormously more favorable in aprotic solvents than in water, and two classes of contributing factors have been proposed to explain this energetic difference, focusing respectively on the isolated and hydrogen-bonded species: (I) water stabilizes the dissociated donor and acceptor groups much better than aprotic solvents, thereby reducing the driving force for hydrogen bond formation; and (II) water lengthens hydrogen bonds compared to aprotic environments, thereby decreasing the potential energy within the hydrogen bond. Each model has been proposed to provide a dominant contribution to Delta G(f), but incisive tests that distinguish the importance of these contributions are lacking. Here we directly test the structural basis of model II. Neutron crystallography, NMR spectroscopy, and quantum mechanical calculations demonstrate that O-H center dot center dot center dot O hydrogen bonds in crystals, chloroform, acetone, and water have nearly identical lengths and very similar potential energy surfaces despite Delta G(f) differences >8 kcal/mol across these solvents. These results rule out a substantial contribution from solvent-dependent differences in hydrogen bond structure and potential energy after association (model II) and thus support the conclusion that differences in hydrogen bond Delta G(f) are predominantly determined by solvent interactions with the dissociated groups (model I). These findings advance our understanding of universal hydrogen-bonding interactions and have important implications for biology and engineering.

  12. Minimising hydrogen sulphide generation during steam assisted production of heavy oil

    OpenAIRE

    Wren Montgomery; Sephton, Mark A.; Watson, Jonathan S.; Huang Zeng; Andrew C. Rees

    2015-01-01

    The majority of global petroleum is in the form of highly viscous heavy oil. Traditionally heavy oil in sands at shallow depths is accessed by large scale mining activities. Recently steam has been used to allow heavy oil extraction with greatly reduced surface disturbance. However, in situ thermal recovery processes can generate hydrogen sulphide, high levels of which are toxic to humans and corrosive to equipment. Avoiding hydrogen sulphide production is the best possible mitigation strateg...

  13. AN EVALUATION OF HYDROGEN INDUCED CRACKING SUSCEPTIBILITY OF TITANIUM ALLOYS IN US HIGH-LEVEL NUCLEAR WASTE REPOSITORY ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    G. De; K. Mon; G. Gordon; D. Shoesmith; F. Hua

    2006-02-21

    This paper evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain nuclear waste repository with particular emphasis on the. effect of the oxide passive film on the hydrogen absorption process of titanium alloys being evaluated. The titanium alloys considered in this review include Ti 2, 5 , 7, 9, 11, 12, 16, 17, 18, 24 and 29. In general, the concentration of hydrogen in a titanium alloy can increase due to absorption of atomic hydrogen produced from passive general corrosion of that alloy or galvanic coupling of it to a less noble metal. It is concluded that under the exposure conditions anticipated in the Yucca Mountain repository, the HIC of titanium drip shield will not occur because there will not be sufficient hydrogen in the metal even after 10,000 years of emplacement. Due to the conservatisms adopted in the current evaluation, this assessment is considered very conservative.

  14. Hydrogen embrittlement of type 410 stainless steel in sodium chloride, sodium sulfate, and sodium hydroxide environments at 90 C

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rodriguez, J.G.; Salinas-Bravo, V.M. [Inst. de Investigaciones Electricas, Cuernavaca (Mexico). Dept. Fisico Quimica Aplicada; Martinez-Villafane, A. [Centro de Investigaciones en Materiales Avanzados Leon Tolstoi, Chihuahua (Mexico)

    1997-06-01

    Susceptibility of martensitic type 410 (UNS S41000) stainless steel (SS) to environmental cracking was evaluated at 90 C in concentrated sodium chloride, sodium sulfate and sodium hydroxide solutions, all of which are environments related to steam turbine conditions, using the slow strain rate testing (SSRT) technique. In NaCl, the effects of solution pH, concentration, and anodic and cathodic polarization were investigated. Tests were supplemented by detailed electron fractography and hydrogen permeation measurements. A clear correlation was found between the degree of embrittlement and the amount of hydrogen permeating the steel, suggesting a hydrogen-induced cracking mechanism.

  15. Electricity-assisted biological hydrogen production from acetate by Geobacter sulfurreducens.

    Science.gov (United States)

    Geelhoed, Jeanine S; Stams, Alfons J M

    2011-01-15

    Geobacter sulfurreducens is a well-known current-producing microorganism in microbial fuel cells, and is able to use acetate and hydrogen as electron donor. We studied the functionality of G. sulfurreducens as biocatalyst for hydrogen formation at the cathode of a microbial electrolysis cell (MEC). Geobacter sulfurreducens was grown in the bioelectrode compartment of a MFC with acetate as the substrate and reduction of complexed Fe(III) at the counter electrode. After depletion of the acetate the electrode potential of the bioelectrode was decreased stepwise to -1.0 V vs Ag/AgCl reference. Production of negative current was observed, which increased in time, indicating that the bioelectrode was now acting as biocathode. Headspace analyses carried out at electrode potentials ranging from -0.8 to -1.0 V showed that hydrogen was produced, with higher rates at more negative cathode potentials. Subsequently, the metabolic properties of G. sulfurreducens for acetate oxidation at the anode and hydrogen production at the cathode were combined in one-compartment membraneless MECs operated at applied voltages of 0.8 and 0.65 V. After two days, current densities were 0.44 A m(-2) at 0.8 V applied voltage and 0.22 A m(-2) at 0.65 V, using flat-surface carbon electrodes for both anode and cathode. The cathodic hydrogen recovery ranged from 23% at 0.5 V applied voltage to 43% at 0.9 V.

  16. Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method describes mechanical test methods and defines acceptance criteria for coating and plating processes that can cause hydrogen embrittlement in steels. Subsequent exposure to chemicals encountered in service environments, such as fluids, cleaning treatments or maintenance chemicals that come in contact with the plated/coated or bare surface of the steel, can also be evaluated. 1.2 This test method is not intended to measure the relative susceptibility of different steels. The relative susceptibility of different materials to hydrogen embrittlement may be determined in accordance with Test Method F1459 and Test Method F1624. 1.3 This test method specifies the use of air melted AISI E4340 steel per SAE AMS-S-5000 (formerly MIL-S-5000) heat treated to 260 – 280 ksi (pounds per square inch x 1000) as the baseline. This combination of alloy and heat treat level has been used for many years and a large database has been accumulated in the aerospace industry on its specific response to exposure...

  17. Influence of high pressure hydrogen environment on tensile and fatigue properties of stainless steels at low temperatures

    Science.gov (United States)

    Ogata, T.

    2012-06-01

    Hydrogen environment embrittlement (HEE) of stainless steels in the environment of high pressure and low temperature hydrogen gas was evaluated using a very simple mechanical properties testing procedure. In the method, the high-pressure hydrogen environment is produced just inside the hole in the specimen. In this work, the effects of HEE on fatigue properties for austenitic stainless steels SUS304L and SUS316L were evaluated at 298 and 190 K. The effects of HEE on the tensile properties of higher strength stainless steels, such as strain-hardened 316, SUS630, and other alloys, SUH660 and Alloy 718 were also examined. The less effect of HEE on fatigue properties of SUS316L and tensile properties of strain-hardened 316 were observed compared with SUS304L and other steels at room temperature and 190 K.

  18. Determination of trace nickel in hydrogenated cottonseed oil by electrothermal atomic absorption spectrometry after microwave-assisted digestion.

    Science.gov (United States)

    Zhang, Gai

    2012-01-01

    Microwave digestion of hydrogenated cottonseed oil prior to trace nickel determination by electrothermal atomic absorption spectrometry (ETAAS) is proposed here for the first time. Currently, the methods outlined in U.S. Pharmacopeia 28 (USP28) or British Pharmacopeia (BP2003) are recommended as the official methods for analyzing nickel in hydrogenated cottonseed oil. With these methods the samples may be pre-treated by a silica or a platinum crucible. However, the samples were easily tarnished during sample pretreatment when using a silica crucible. In contrast, when using a platinum crucible, hydrogenated cottonseed oil acting as a reducing material may react with the platinum and destroy the crucible. The proposed microwave-assisted digestion avoided tarnishing of sample in the process of sample pretreatment and also reduced the cycle of analysis. The programs of microwave digestion and the parameters of ETAAS were optimized. The accuracy of the proposed method was investigated by analyzing real samples. The results were compared with the ones by pressurized-PTFE-bomb acid digestion and ones obtained by the U.S. Pharmacopeia 28 (USP28) method. The new method involves a relatively rapid matrix destruction technique compared with other present methods for the quantification of metals in oil.

  19. Ionic Liquid Assisted Acetylene Partial Hydrogenation Over Surface of Palladium Nanoparticles

    Science.gov (United States)

    Farshidfar, Farshad; Kazemzad, Mahmood; Khanlarkhani, Ali; Rezaei, Mehran

    2016-06-01

    The loss of acetylene partial hydrogenation selectivity over bare palladium catalyst is observed by aging. In this study, 1-butyl-3-methyl imidazolinium hydroxide ionic liquid (BMIm[OH]) is loaded on Pd/γ-Al2O3 solid catalyst for enhancing the selectivity and different experimental techniques such as surface area measurements and catalytic performance have been performed to characterize the modified catalyst. Results revealed that the addition of ionic liquid maintains higher selectivity of partial hydrogenation over Pd/γ-Al2O3 catalyst for more than 30h especially at the temperature of acetylene complete removal (>100∘C). The activation energies of partial and complete acetylene hydrogenation on bare and ionic liquid loaded Pd/γ-Al2O3 are also calculated and utilized to clarify the obtained results.

  20. Electron-induced hydrogen loss in uracil in a water cluster environment

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, M.; Kohanoff, J. [Atomistic Simulation Centre, Queen' s University Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom); Fabrikant, I. I., E-mail: ifabrikant1@unl.edu [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA and Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2014-05-14

    Low-energy electron-impact hydrogen loss due to dissociative electron attachment (DEA) to the uracil and thymine molecules in a water cluster environment is investigated theoretically. Only the A{sup ′}-resonance contribution, describing the near-threshold behavior of DEA, is incorporated. Calculations are based on the nonlocal complex potential theory and the multiple scattering theory, and are performed for a model target with basic properties of uracil and thymine, surrounded by five water molecules. The DEA cross section is strongly enhanced when the attaching molecule is embedded in a water cluster. This growth is due to two effects: the increase of the resonance lifetime and the negative shift in the resonance position due to interaction of the intermediate negative ion with the surrounding water molecules. A similar effect was earlier found in DEA to chlorofluorocarbons.

  1. Factors affecting hydrogen-assisted cracking in a commercial tempered martensitic steel: Mn segregation, MnS, and the stress state around abnormal cracks

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Daisuke [Graduate School of Kyushu University, Fukuoka 819-0395 (Japan); Koyama, Motomichi [Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku Fukuoka 819-0395 (Japan); Noguchi, Hiroshi, E-mail: nogu@mech.kyushu-u.ac.jp [Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku Fukuoka 819-0395 (Japan)

    2015-07-29

    The purpose of this paper is to reveal the dominant factors affecting tensile fracture under a hydrogen gas atmosphere. Tensile tests were conducted in hydrogen gas with circumferentially-notched specimens of a commercial tempered martensitic steel. Two specimens were exposed to hydrogen gas for 48 h before tensile testing; the other two specimens were not pre-charged. Longitudinal cracks along the loading direction and a transverse crack perpendicular to the loading direction were observed on a cross section of the non-charged specimen, but there was only one small crack on a cross section of the pre-charged specimen. Electron back scatter diffraction, energy dispersive X-ray spectrometry and finite element method analyses were applied to clarify the relationships among the longitudinal crack, Mn segregation, microstructures of martensitic steel and hydrogen. As a result, it has been demonstrated that Mn segregation and MnS promote hydrogen-assisted cracking in the tempered martensitic steel, causing the longitudinal cracking which is a mechanically non-preferential direction in homogeneous situations. More specifically, we have shown that the role of the Mn segregation is to promote the hydrogen-enhanced decohesion effect (HEDE), which is particularly important for crack propagation in the present case. These considerations indicate that the presence of Mn is crucially important for hydrogen-assisted cracking associated with hydrogen-enhanced localized plasticity (HELP) as well as HEDE.

  2. Identifying the Potential for Robotics to Assist Older Adults in Different Living Environments.

    Science.gov (United States)

    Mitzner, Tracy L; Chen, Tiffany L; Kemp, Charles C; Rogers, Wendy A

    2014-04-01

    As the older adult population grows and becomes more diverse, so will their needs and preferences for living environments. Many adults over 65 years of age require some assistance [1, 2]; yet it is important for their feelings of well-being that the assistance not restrict their autonomy [3]. Not only is autonomy correlated with quality of life [4], autonomy enhancement may improve functionality [2, 5]. The goal of this paper is to provide guidance for the development of technology to enhance autonomy and quality of life for older adults. We explore the potential for robotics to meet these needs. We evaluated older adults' diverse living situations and the predictors of residential moves to higher levels of care in the United States. We also examined older adults' needs for assistance with activities of daily living (ADLs), instrumental activities of daily living (IADLs), and medical conditions when living independently or in a long-term care residence. By providing support for older adults, mobile manipulator robots may reduce need-driven, undesired moves from residences with lower levels of care (i.e., private homes, assisted living) to those with higher levels of care (i.e., skilled nursing).

  3. Assistive Technologies in a Workplace Environment: Barriers for the Employment of People with Disabilities

    Directory of Open Access Journals (Sweden)

    Sheryl Beverley Buckley

    2011-10-01

    Full Text Available Purpose: The employment equity policies and implementation of technology-specific guidelines within the South African ‘Code of Good Practice on the Employment of People with Disabilities’, was created to encourage employment equity for employees with disabilities, by companies in Johannesburg.  This study reports on the results of the investigation in assistive technologies in a workplace environment, and barriers for the employment of people with disabilities in the South African environment.Method: Qualitative data, collected from two retail and service companies in the form of semi-structured individual and focus group interviews, was analysed using a constant comparative method, identifying major themes and sub-themes.Results: A surprisingly small number of persons with disabilities were found to be employed by participating companies, which tended not to focus on these people when formulating their policies and plans. In addition, technological aspects of the Code were largely unacknowledged, with little effort being made to accommodate the needs of persons with disabilities. An even lower incidence of assistive technology usage was found, along with a large number of conceptual and perceived barriers that hinder the employment of people with disabilities and the implementation of appropriate technology.Key words: assistive technologies, disability accommodation guidelines, barriers for employment, disabilities, policy doi 10.5463/DCID.v22i2.32

  4. High-magnetic-field-assisted scattering of electrons with atomic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Ajoy [Laban Hrad Vidyapith, AD-369, Salt Lake City, Kolkata 700064 (India)

    2007-04-28

    We have investigated quantum mechanically the scattering of electrons off atomic hydrogen in a strong magnetic field. Elastic, inelastic, backward and total scattering cross sections are reported. Near-resonance behaviour of the system is analysed. Results are presented after evaluating and summing all-order Born series under suitable physical conditions.

  5. Hydrogen production by hybrid electrolysis combined with assistance of solar energy

    Science.gov (United States)

    Takehara, Z.; Yoshizawa, S.

    As a means of reducing the electrical energy needed to produce hydrogen from water, a process is presented, whereby an aqueous sulfuric acid solution containing Fe(2+) ions is electrolyzed, hydrogen being an energy storage material which levels load variation of electrical utilities. In an electrolytic cell, Fe(2+) ions are oxidized on a packed bed carbon anode to form Fe(3+) ions. H(+) ions diffuse through a cation exchange membrane, and are then reduced to hydrogen gas on the cathode. The Fe(3+) ions, produced in the cell, are decomposed in a photodecomposition cell. Oxygen evolves on the TiO2 anode, illuminated by solar light; the produced H(+) ions are diffused through a cation exchange membrane and electrons move through the metal inserted in the membrane to the cathode. The solution containing Fe(+) ions, introduced in the cathode chamber, is reduced cathodically on the platinized platinum. Cell voltage is determined for the process and it is found to be only about 1.0 V for electrolysis of 50mA/sq cm at room temperature. For the case of direct electrolysis of 2N NaOH aqueous solution, the cell voltage is 2.2V electrolysis of 30mA/sq cm. Results indicate a large reduction of electrical energy needed for the production of hydrogen in the process presented.

  6. Pacific Northwest Laboratory annual report for 1990 to the Assistant Secretary for Environment, Safety, and Health

    Energy Technology Data Exchange (ETDEWEB)

    Faust, L.G.; Moraski, R.V.; Selby, J.M.

    1991-05-01

    Part 5 of the 1990 Annual Report to the US Department of Energy's Assistant Secretary for Environment, Safety, and Health presents Pacific Northwest Laboratory's progress on work performed for the Office of Environmental Guidance, the Office of Environmental Compliance, the Office of Environmental Audit, the Office of National Environmental Policy Act Project Assistance, the Office of Nuclear Safety, the Office of Safety Compliance, and the Office of Policy and Standards. For each project, as identified by the Field Work Proposal, there is an article describing progress made during fiscal year 1990. Authors of these articles represent a broad spectrum of capabilities derived from five of the seven technical centers of the Laboratory, reflecting the interdisciplinary nature of the work.

  7. Effective Pincer Cobalt Precatalysts for Lewis Acid Assisted CO2 Hydrogenation.

    Science.gov (United States)

    Spentzos, Ariana Z; Barnes, Charles L; Bernskoetter, Wesley H

    2016-08-15

    The pincer ligand MeN[CH2CH2(P(i)Pr2)]2 ((iPr)PNP) was employed to support a series of cobalt(I) complexes, which were crystallographically characterized. A cobalt monochloride species, ((iPr)PNP)CoCl, served as a precursor for the preparation of several cobalt precatalysts for CO2 hydrogenation, including a cationic dicarbonyl cobalt complex, [((iPr)PNP)Co(CO)2](+). When paired with the Lewis acid lithium triflate, [((iPr)PNP)Co(CO)2](+) affords turnover numbers near 30 000 (at 1000 psi, 45 °C) for CO2-to-formate hydrogenation, which is a notable increase in activity from previously reported homogeneous cobalt catalysts. Though mechanistic information regarding the function of the precatalysts remains limited, multiple experiments suggest the active species is a molecular, homogeneous [((iPr)PNP)Co] complex.

  8. Microbial corrosion and cracking in steel. A concept for evaluation of hydrogen-assisted stress corrosion cracking in cathodically protected high-pressure gas transmission pipelines

    DEFF Research Database (Denmark)

    Nielsen, Lars Vendelbo

    of high-strength pipeline steel and the concentration of hydrogen present in the steel. B. Determine the degree hydrogen absorption by cathodically protected steel exposed in natural soil sediment, which include activity of sulphate-reducing bacteria (SRB). C. Compare the above points with fracture......An effort has been undertaken in order to develop a concept for evaluation of the risk of hydrogen-assisted cracking in cathodically protected gas transmission pipelines. The effort was divided into the following subtasks: A. Establish a correlation between the fracture mechanical properties...... in this steel....

  9. Hydrogen bonding-assisted thermal conduction in β-sheet crystals of spider silk protein

    Science.gov (United States)

    Zhang, Lin; Chen, Teli; Ban, Heng; Liu, Ling

    2014-06-01

    Using atomistic simulations, we demonstrate that β-sheet, an essential component of spider silk protein, has a thermal conductivity 1-2 orders of magnitude higher than that of some other protein structures reported in the literature. In contrast to several other nanostructured materials of similar bundled/layered structures (e.g. few-layer graphene and bundled carbon nanotubes), the β-sheet is found to uniquely feature enhanced thermal conductivity with an increased number of constituting units, i.e. β-strands. Phonon analysis identifies inter-β-strand hydrogen bonding as the main contributor to the intriguing phenomenon, which prominently influences the state of phonons in both low- and high-frequency regimes. A thermal resistance model further verifies the critical role of hydrogen bonding in thermal conduction through β-sheet structures.Using atomistic simulations, we demonstrate that β-sheet, an essential component of spider silk protein, has a thermal conductivity 1-2 orders of magnitude higher than that of some other protein structures reported in the literature. In contrast to several other nanostructured materials of similar bundled/layered structures (e.g. few-layer graphene and bundled carbon nanotubes), the β-sheet is found to uniquely feature enhanced thermal conductivity with an increased number of constituting units, i.e. β-strands. Phonon analysis identifies inter-β-strand hydrogen bonding as the main contributor to the intriguing phenomenon, which prominently influences the state of phonons in both low- and high-frequency regimes. A thermal resistance model further verifies the critical role of hydrogen bonding in thermal conduction through β-sheet structures. Electronic supplementary information (ESI) available: Structure of the β-sheets, computational model, determination of area and temperature gradient, and additional phonon DOS results. See DOI: 10.1039/c4nr01195c

  10. Experimental and Observational Studies of Molecular Hydrogen in Interstellar and Circumstellar Environments

    Science.gov (United States)

    Hoadley, Keri

    2017-08-01

    Understanding the evolution of gas over the lifetime of protoplanetary disks provides us with important clues about how planet formation mechanisms drive the diversity of exoplanetary systems observed to date. In the first part of my thesis, I discuss how I use fluorescent emission observations of molecular hydrogen (H2) in the far-ultraviolet (far-UV) with the Hubble Space Telescope to study the warm molecular regions (a distributions of H 2 help provide important constraints on the radiation properties of gas left in the inner disk of protoplanetary disks as they evolve. Additionally, I analyzed the absorption component of these fluorescence features, embedded within the hydrogen Lyman-alpha emission line produced by the accretion of material onto the host protostar. I present column density and temperature estimates for the H2 populations in each disk sightline, and discuss the behavior and possible spatial origins of these hot molecules. As part of my thesis, I address some observational requirements needed to gain further insights into the behavior of the warm, gaseous protoplanetary disk, focusing specifically on a spectrograph concept for the next-generation LUVOIR Surveyor. I discuss a testbed instrument, the Colorado High-resolution Echelle Stellar Spectrograph (CHESS), built as a demonstration of one component of the LUVOIR spectrograph and new technological improvements to UV optical components for the next generation of near- to far-UV astrophysical observatories. CHESS is a far-UV sounding rocket experiment designed to probe the warm and cool atoms and molecules near sites of recent star formation in the local interstellar medium. I present the science goals, design, research and development components, and calibration of the CHESS instrument. I provide results on observations taken during both launches of CHESS, with detailed analysis of the epsilon Per sightline, as inferred from the flight data. I conclude by providing future works and simple

  11. The combined influence of chemical, metallurgical and mechanical factors on environment assisted cracking

    Science.gov (United States)

    Williams, D. P., III; Pao, P. S.; Wei, R. P.

    1979-01-01

    The principal aim of the paper is to re-emphasize and focus on both the multidisciplinary nature of the environment assisted cracking or embrittlement phenomenon. The multiplicity of factors involved in the embrittlement process is indicated, the mutual dependence of these factors and the influences of mechanical and environmental conditions are considered, and the interactions of various factors in determining the overall embrittlement response are discussed. The need for an interdisciplinary approach for resolving the major differences and for understanding embrittlement is outlined.

  12. Structural stability of hydrogenated amorphous carbon overcoats used in heat-assisted magnetic recording investigated by rapid thermal annealing

    KAUST Repository

    Wang, N.

    2013-01-01

    Ultrathin amorphous carbon (a-C) films are extensively used as protective overcoats of magnetic recording media. Increasing demands for even higher storage densities have necessitated the development of new storage technologies, such as heat-assisted magnetic recording (HAMR), which uses laser-assisted heating to record data on high-stability media that can store single bits in extremely small areas (∼1 Tbit/in.2). Because HAMR relies on locally changing the coercivity of the magnetic medium by raising the temperature above the Curie temperature for data to be stored by the magnetic write field, it raises a concern about the structural stability of the ultrathin a-C film. In this study, rapid thermal annealing (RTA) experiments were performed to examine the thermal stability of ultrathin hydrogenated amorphous carbon (a-C:H) films deposited by plasma-enhanced chemical vapor deposition. Structural changes in the a-C:H films caused by RTA were investigated by x-ray photoelectron spectroscopy, Raman spectroscopy, x-ray reflectivity, and conductive atomic force microscopy. The results show that the films exhibit thermal stability up to a maximum temperature in the range of 400-450 °C. Heating above this critical temperature leads to hydrogen depletion and sp 2 clustering. The critical temperature determined by the results of this study represents an upper bound of the temperature rise due to laser heating in HAMR hard-disk drives and the Curie temperature of magnetic materials used in HAMR hard disks. © 2013 American Institute of Physics.

  13. Divacancy-assisted transition metal adsorption on the BN graphene and its interaction with hydrogen molecules: a theoretical study

    Science.gov (United States)

    Chen, Ying; Wang, Hongmei; Wang, Hongxia; Zhao, Jing-xiang; Cai, Qing-hai; Wang, Xiao-Guang; Ding, Yi-hong

    2013-05-01

    We have performed first-principles calculations to study the chemical functionalization of the BN graphene with divacancy (DV) defect by 12 different transition metal (TM) atoms, including Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pt, and Au. The results indicate that the DV defect can assist the adsorption of TM atoms on BN graphene. Moreover, some impurity bands are induced within the band gap of DV-BN graphene, leading to the modification of its electronic properties in various ways. Interestingly, Ti- and Co-adsorbed DV-BN graphenes are found to possess ferromagnetic characteristic, while antiferromagnetic state is preferred for V-, Mn-, and Fe-functionalized DV-BN graphenes, and the paramagnetic state is the ground state for Sc-, Cr-, Ni-, Cu, Zn-, Pt-, and Au-decorated DV-BN graphenes. Finally, aiming at evaluating the potential of these functionalized BN graphenes in hydrogen storage, we study their interaction with H2 molecules. It is found that the dispersed Sc, V, and Cr on DV-BN graphene are able to adsorb up to three H2 molecules as strongly as 0.25-0.58 eV/H2, suggesting that the three nanomaterials may be suitable candidates for hydrogen storage.

  14. Divacancy-assisted transition metal adsorption on the BN graphene and its interaction with hydrogen molecules: a theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying; Wang, Hongmei; Wang, Hongxia [Key Laboratory for Photoelectric Bandgap Materials, Ministry of Education, Harbin Normal University, Harbin 150025 (China); Zhao, Jing-xiang, E-mail: xjz_hmily@yahoo.com.cn [Key Laboratory for Photoelectric Bandgap Materials, Ministry of Education, Harbin Normal University, Harbin 150025 (China); Cai, Qing-hai; Wang, Xiao-Guang [Key Laboratory for Photoelectric Bandgap Materials, Ministry of Education, Harbin Normal University, Harbin 150025 (China); Ding, Yi-hong, E-mail: yhdd@jlu.edu.cn [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China)

    2013-05-15

    We have performed first-principles calculations to study the chemical functionalization of the BN graphene with divacancy (DV) defect by 12 different transition metal (TM) atoms, including Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pt, and Au. The results indicate that the DV defect can assist the adsorption of TM atoms on BN graphene. Moreover, some impurity bands are induced within the band gap of DV-BN graphene, leading to the modification of its electronic properties in various ways. Interestingly, Ti- and Co-adsorbed DV-BN graphenes are found to possess ferromagnetic characteristic, while antiferromagnetic state is preferred for V-, Mn-, and Fe-functionalized DV-BN graphenes, and the paramagnetic state is the ground state for Sc-, Cr-, Ni-, Cu, Zn-, Pt-, and Au-decorated DV-BN graphenes. Finally, aiming at evaluating the potential of these functionalized BN graphenes in hydrogen storage, we study their interaction with H{sub 2} molecules. It is found that the dispersed Sc, V, and Cr on DV-BN graphene are able to adsorb up to three H{sub 2} molecules as strongly as 0.25–0.58 eV/H{sub 2}, suggesting that the three nanomaterials may be suitable candidates for hydrogen storage.

  15. Principles of hydrogen radical mediated peptide/protein fragmentation during matrix-assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Asakawa, Daiki

    2016-07-01

    Matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) is a very easy way to obtain large sequence tags and, thereby, reliable identification of peptides and proteins. Recently discovered new matrices have enhanced the MALDI-ISD yield and opened new research avenues. The use of reducing and oxidizing matrices for MALDI-ISD of peptides and proteins favors the production of fragmentation pathways involving "hydrogen-abundant" and "hydrogen-deficient" radical precursors, respectively. Since an oxidizing matrix provides information on peptide/protein sequences complementary to that obtained with a reducing matrix, MALDI-ISD employing both reducing and oxidizing matrices is a potentially useful strategy for de novo peptide sequencing. Moreover, a pseudo-MS(3) method provides sequence information about N- and C-terminus extremities in proteins and allows N- and C-terminal side fragments to be discriminated within the complex MALDI-ISD mass spectrum. The combination of high mass resolution of a Fourier transform-ion cyclotron resonance (FTICR) analyzer and the software suitable for MALDI-ISD facilitates the interpretation of MALDI-ISD mass spectra. A deeper understanding of the MALDI-ISD process is necessary to fully exploit this method. Thus, this review focuses first on the mechanisms underlying MALDI-ISD processes, followed by a discussion of MALDI-ISD applications in the field of proteomics. © 2014 Wiley Periodicals, Inc., Mass Spec Rev 35:535-556, 2016.

  16. Mesoporous Silica-Supported Sulfonyldiamine Ligand for Microwave-Assisted Transfer Hydrogenation

    Directory of Open Access Journals (Sweden)

    Shaheen M. Sarkar

    2015-01-01

    Full Text Available N-Sulfonyl-1,2-diamine ligands, derived from 1,2-diaminocyclohexane and 1,2-diaminopropane, were immobilized onto mesoporous SBA-15 silica. The SBA-15-supported sulfonyldiamine-Ru complex was prepared in situ under microwave heating at 60 W for 3 min. The prepared sulfonyldiamine-Ru complex was used as an efficient catalyst for the transfer hydrogenation of ketones to the corresponding secondary alcohols. The heterogeneous complex showed extremely high catalytic activity with 99% conversion rate under microwave heating condition. The complexes were regenerated by simple filtration and reused two times without significant loss of activity.

  17. Effects of hydrogen on mechanical properties of Cr-Mo steel equipment in refinery environments

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, P. [Industeel Belgium, Charleroi (Belgium); Pillot, S.; Bourges, P. [Industeel Creusot, Le Creusot (France). Centre de Reserche des Materiaux du Creusot; Masson, G. [ArcelorMittal Global Plates Strategy, Luxemboug (Luxembourg); Coudreuse, L. [Industeel Loire, Rive de Gier (France)

    2008-07-01

    This paper discussed an experimental study conducted to determine the effect of hydrogen on the mechanical properties of steel refinery pressure vessels. Hydrogen was introduced into the steel during service as well as during a shut-down operation in order to determine tensile and Charpy-impact properties of the base metal, heat-affected zone, and weld metal. Charpy impact transition curves were assessed in order to evaluate the effect of hydrogen content on the fracture aspect transition temperature (FATT). Tensile specimens were charged with hydrogen in an autoclave at temperatures lower than 450 degrees C. Creep tests were conducted to measure the variation of creep strength and ductility between specimens. The effect of hydrogen on different weld microstructures was examined. Results of the study showed that the FATT was increased by the presence of hydrogen in the metal. Sensitivities in the weld metal were noted. Tests conducted to examine the influence of hydrogen on creep properties demonstrated that the presence of hydrogen reduced rupture times. Hydrogen affected the static, quasi-static, and dynamic properties of the steel samples. It was concluded that vanadium alloyed materials are less sensitive to hydrogen than standard steel grades. 3 refs., 9 tabs., 11 figs.

  18. Hydrogen Environment Assisted Cracking of Ultra-High Strength AetMet(Trademark) 100 Steel

    Science.gov (United States)

    2006-01-01

    strength alloys[17] and at the region of maximum crack tip hydrostatic tension for IIAC[871. Traditional UIISS such as AISI 4340 and 300M are particularly...of 1725 MNPa[21藁. Despite these advances, AerMetTM 100 is susceptible to HAC comparable to older UHSSfI 8󈧝- 301 . For example, IRAC of AerMetTM 100...older UHSSs such as AISI 4340, 18Ni Maraging and 300M show severe IG HEAC for a wide range of composition, thermal treatment and environmental

  19. Hot-wire substoichiometric tungsten oxide films deposited in hydrogen environment with n-type conductivity

    Science.gov (United States)

    Kostis, I.; Michalas, L.; Vasilopoulou, M.; Konofaos, N.; Papaioannou, G.; Iliadis, A. A.; Kennou, S.; Giannakopoulos, K.; Papadimitropoulos, G.; Davazoglou, D.

    2012-11-01

    Substoichiometric tungsten oxide nanostructured films were synthesized by a hot-wire deposition technique in hydrogen-rich environment and characterized for their structural and electrical properties. A semiconducting behaviour was identified, allowing n-type conductivity even at room temperature which is an important result since it is well known that fully stoichiometric tungsten trioxide is nearly an insulator. Current-voltage characteristics for various temperatures were measured for tungsten oxide/Si heterostructures and analysed using proper modelling. As a result, the conduction mechanism inside the films was identified and found to be of a dual nature, with variable range hopping being dominant at near room temperatures. The saturation current was found to be thermally activated and the activation energy was calculated at 0.40 eV and the grain boundaries barrier at 150 meV. From Hall measurements it was also revealed that the dominant carriers are electrons and a carrier concentration of about 1014 cm-3 was estimated.

  20. Susceptibility of Listeria monocytogenes biofilms and planktonic cultures to hydrogen peroxide in food processing environments.

    Science.gov (United States)

    Yun, Hyun Sun; Kim, Younghoon; Oh, Sejong; Jeon, Woo Min; Frank, Joseph F; Kim, Sae Hun

    2012-01-01

    Recent studies have indicated that Listeria monocytogenes formed biofilms on the surface of food processing equipment, and may survive sanitization treatments. The purpose of this study was to compare the susceptibility of L. monocytogenes grown in either a biofilm or planktonic culture when exposed to hydrogen peroxide (H(2)O(2)). Twelve strains of biofilm-forming L. monocytogenes and their planktonic counterparts were treated with various concentrations of H(2)O(2) (1, 6, and 10%), and the cell survival was then determined at 10-min exposure intervals. When grown as a biofilm, L. monocytogenes was significantly more resistant to H(2)O(2) than under planktonic culture conditions. Planktonic L. monocytogenes strains exhibited significantly different susceptibility to 1% H(2)O(2). Equally interestingly, biofilms of the 12 L. monocytogenes strains also inhibited different survival rates after being treated with 6 and 10% H(2)O(2). However, most of the biofilms recovered to a population of 2-9 log CFU/glass fiber filter (GFF) after a 24-h re-growth period. These results indicate that there was no significant correlation between the H(2)O(2) resistance of biofilm- and planktonic-cultured cells, and suggest that different mechanisms for the resistance to sanitation or disinfection underly the persistence of certain strains in food-processing environments.

  1. Structural, nanomechanical and variable range hopping conduction behavior of nanocrystalline carbon thin films deposited by the ambient environment assisted filtered cathodic jet carbon arc technique

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Rawal, Ishpal; Tripathi, R.K. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Srivastava, A.K. [Electron and Ion Microscopy, Sophisticated and Analytical Instruments, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Kumar, Mahesh [Ultrafast Opto-Electronics and Tetrahertz Photonics Group, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India)

    2015-04-15

    Highlights: • Nanocrystalline carbon thin films are grown by filtered cathodic jet carbon arc process. • Effect of gaseous environment on the properties of carbon films has been studied. • The structural and nanomechanical properties of carbon thin films have been studied. • The VRH conduction behavior in nanocrystalline carbon thin films has been studied. - Abstract: This paper reports the deposition and characterization of nanocrystalline carbon thin films by filtered cathodic jet carbon arc technique assisted with three different gaseous environments of helium, nitrogen and hydrogen. All the films are nanocrystalline in nature as observed from the high resolution transmission electron microscopic (HRTEM) measurements, which suggests that the nanocrystallites of size ∼10–50 nm are embedded though out the amorphous matrix. X-ray photoelectron spectroscopic studies suggest that the film deposited under the nitrogen gaseous environment has the highest sp{sup 3}/sp{sup 2} ratio accompanied with the highest hardness of ∼18.34 GPa observed from the nanoindentation technique. The film deposited under the helium gaseous environment has the highest ratio of the area under the Raman D peak to G peak (A{sub D}/A{sub G}) and the highest conductivity (∼2.23 S/cm) at room temperature, whereas, the film deposited under the hydrogen environment has the lowest conductivity value (2.27 × 10{sup −7} S/cm). The temperature dependent dc conduction behavior of all the nanocrystalline carbon thin films has been analyzed in the light of Mott’s variable range hopping (VRH) conduction mechanism and observed that all the films obey three dimension VRH conduction mechanism for the charge transport.

  2. Plasma assisted fuel reforming for on-board hydrogen rich gas production

    OpenAIRE

    Darmon, Adeline; Rollier, Jean-Damien; Duval, Emmanuelle; Gonzalez-Aguilar, Jose; Metkemeijer, Rudolf; Fulcheri, Laurent

    2006-01-01

    Texte disponible en suivant le lien ci-dessous : http://www.cder.dz/A2H2/Medias/Download/Proc%20PDF/PARALLEL%20SESSIONS/%5BS06%5D%20Production%20-%20Hydrocarbons/14-06-06/162.pdf; International audience; Plasma assisted fuel reforming technology appears particularly attractive for automotive applications, especially regarding compactness, response time and absence of catalyst element. In 2003, Renault and CEP have initiated a research programme on this subject. A test bench allowing reformer ...

  3. Intramolecular resonance-assisted hydrogen bonds: A theoretical description by means of atomic charges and charge fluxes

    Science.gov (United States)

    Baranović, Goran

    2014-01-01

    The characterization of intramolecular H-bonds in terms of atomic charges and charge fluxes (at the B3LYP/cc-pVTZ level of theory) has been extended to the case of the so called resonance-assisted (RA) H-bonds. A quadratic correlation between the charge fluxes ϕH and the molecular IR absorption coefficients E that includes the entire family of the studied systems (31 of them) containing both intra- and intermolecular hydrogen bonds (O-H⋯O/N) confirmed the critical importance of the charge fluxes on the IR intensity enhancements. Since they reflect changing of the atomic charge distribution during the normal modes of vibrations, the dynamic nature of hydrogen bonding properties has been re-emphasized. The changes of the charge flux of the hydroxyl hydrogen in an RA intramolecular H-bond are between those for “free” OH bonds and the values calculated for intermolecular H-bonds. The transition “free” → intramolecular → intermolecular is gradual and therefore the hydrogen charge flux can be considered as practically sufficient to give quantitative measure to the intuitively obvious statement that “intramolecular H-bonding is somehow in between no H-bonding situation and intermolecular H-bonding” and thus provide a quantitative and yet simple parameterization of H-bond strength. In strictly planar molecules, the difference of the sums of charges of atoms participating in the 6-membered H-bond ring ΔΣ can serve as a measure of the charge delocalization after the H-bond is formed. The electronic charge is withdrawn from the group of six atoms when the H-bond is formed in nitrophenol (ΔΣ = -0.07), while the opposite is true (ΔΣ = +0.03) for 2-hydroxy benzylidene amine. The corresponding values of the geometrical resonance parameter Δ are 0.39 and 0.37, respectively, similar to those found for 2-hydroxy acetophenone and 2-hydroxy benzaldehyde. The extent of the π-electron delocalization as measured by the resonance parameter Δ does not follow

  4. Hydrogen bonding-assisted interaction between amitriptyline hydrochloride and hemoglobin: spectroscopic and molecular dynamics studies.

    Science.gov (United States)

    Maurya, Neha; Maurya, Jitendra Kumar; Kumari, Meena; Khan, Abbul Bashar; Dohare, Ravins; Patel, Rajan

    2017-05-01

    Herein, we have explored the interaction between amitriptyline hydrochloride (AMT) and hemoglobin (Hb), using steady-state and time-resolved fluorescence spectroscopy, UV-visible spectroscopy, and circular dichroism spectroscopy, in combination with molecular docking and molecular dynamic (MD) simulation methods. The steady-state fluorescence reveals the static quenching mechanism in the interaction system, which was further confirmed by UV-visible and time-resolved fluorescence spectroscopy. The binding constant, number of binding sites, and thermodynamic parameters viz. ΔG, ΔH, ΔS are also considered; result confirms that the binding of the AMT with Hb is a spontaneous process, involving hydrogen bonding and van der Waals interactions with a single binding site, as also confirmed by molecular docking study. Synchronous fluorescence, CD data, and MD simulation results contribute toward understanding the effect of AMT on Hb to interpret the conformational change in Hb upon binding in aqueous solution.

  5. Gel-combustion-synthesized ZnO nanoparticles for visible light-assisted photocatalytic hydrogen generation

    Indian Academy of Sciences (India)

    2017-04-01

    Zinc oxide nanoparticles (ZnO NPs) synthesized by the gel combustion technique using a bio-fuel, cassava starch (root tubers of Manihot esculenta), have been characterized by various techniques. The X-ray diffractionpattern reveals hexagonal wurtzite structure. The particle size averaged around 45nm with an excellent band gap of 2.5 eV. The scanning electron and transmission electron microscopic images confirm the ZnO NPs to be agglomerated with loop- and chain-like morphology. The ZnO NPs prepared by this method is a promising candidate for photocatalytic hydrogen generation (41 $\\mu$mol h$^{−1}$ g$^{−1}$) under UV light illumination and (140 $\\mu$mol h$^{−1}$ g$^{−1}$) under visible light illumination.

  6. Seawater-Assisted Self-Healing of Catechol Polymers via Hydrogen Bonding and Coordination Interactions.

    Science.gov (United States)

    Li, Jincai; Ejima, Hirotaka; Yoshie, Naoko

    2016-07-27

    It is highly desirable to prevent crack formation in polymeric materials at an early stage and to extend their lifespan, particularly when repairs to these materials would be difficult for humans. Here, we designed and synthesized catechol-functionalized polymers that can self-heal in seawater through hydrogen bonding and coordination. These bioinspired acrylate polymers are originally viscous materials, but after coordination with environmentally safe, common metal cations in seawater, namely, Ca(2+) and Mg(2+), the mechanical properties of the polymers were greatly enhanced from viscous to tough, hard materials. Reduced swelling in seawater compared with deionized water owing to the higher osmotic pressure resulted in greater toughness (∼5 MPa) and self-healing efficiencies (∼80%).

  7. Laser assisted patterning of hydrogenated amorphous silicon for interdigitated back contact silicon heterojunction solar cell

    Science.gov (United States)

    De Vecchi, S.; Desrues, T.; Souche, F.; Muñoz, D.; Lemiti, M.

    2012-10-01

    This work reports on the elaboration of a new industrial process based on laser selective ablation of dielectric layers for Interdigitated Back Contact Silicon Heterojunction (IBC Si-HJ) solar cells fabrication. Choice of the process is discussed and cells are processed to validate its performance. A pulsed green laser (515nm) with 10-20ns pulse duration is used for hydrogenated amorphous silicon (a-Si:H) layers patterning steps, whereas metallization is made by screen printed. High Open-Circuit Voltage (Voc=699mV) and Fill Factor (FF=78.5%) values are obtained simultaneously on IBC Si-HJ cells, indicating a high surface passivation level and reduced resistive losses. An efficiency of 19% on non textured 26 cm² solar cells has been reached with this new industrial process.

  8. Effects of hydrogen gas environment on non-propagation phenomena of a type 304 austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Y.; Matsuyama, T.; Oda, Y.; Noguchi, H.; Higashida, K. [Hakozaki, Higashi-ku, Fukuoka (Japan)

    2005-07-01

    In order to investigate the hydrogen gas effect on non-propagation phenomena of a type 304 austenitic stainless steel, fatigue tests with in-situ observation using a Scanning Laser Microscope were performed in air, in 0.18 MPa hydrogen gas and in 0.18 MPa nitrogen gas. A non-propagating crack was observed during the fatigue test in air. At almost the same stress level of non-propagating in air, non-propagating cracks were also observed in fatigue tests in hydrogen and in nitrogen. Stress level of the non-propagation is not sufficiently different in the three environments. However, the process up to non-propagation differs from each other, for example, the crack path and debris. (orig.)

  9. Hydrogen isotope composition of natural gases from the Tarim Basin and its indication of depositional environments of the source rocks

    Institute of Scientific and Technical Information of China (English)

    LIU QuanYou; DAI JinXing; LI Jian; ZHOU QingHua

    2008-01-01

    By measuring carbon and hydrogen isotope compositions for C1, C2 and C3 of 74 gas samples, natural gases from the Tarim Basin can be divided into six groups on the basis of their origins: (1) coal-type gas derived from coal measures; (2) coal-type gas generated from the T-J lacustrine mudstones; (3) oil-type gas derived from the Cambrian and low Ordovician marine source rocks; (4) oil-type gas from the source rocks deposited in the marine -transitional facies; (5) mixing gas between gas derived from the Carboniferous transitional source rocks and the Mesozoic humic gas, and (6) mixing gases of of methane in natural gases originating from different type kerogens are affected by both palaeo-environments of the source rock formation (kerogen types) and thermal maturity, with sedimentary environment (kerogen type) as the main controlling factor. Under the similar thermal maturity, the hydrogen isotope composition of methane is more enriched in deuterium in marine environments than lacustrine one. With the increase of thermal maturity and the increase of carbon atomic numbers of environment of the source rock formation. The partial reversal of hydrogen isotopes for gaseous alkanes would be related to the microbial oxidation, mixing of sapropelic and humic gases and / or mixing of gases from similar kerogen sources with various thermal maturities. In the oil-type gas, the sul

  10. Suitability of Tophet C-Alloy 52/Kovar components to hydrogen environments

    Energy Technology Data Exchange (ETDEWEB)

    Gebhart, J.M.; Kelly, M.D.

    1976-06-22

    The suitability of Tophet C-Alloy 52/Kovar weldments to hydrogen embrittlement were investigated because of their potential as candidate materials in fabrication of minaturized initiators for pyrotechnics. Cathodic charged samples were statically loaded for extended periods of time resulting in no load failures and in ductile fracture surfaces indicating resistance to hydrogen embrittlement. 20 figures.

  11. SLAM algorithm applied to robotics assistance for navigation in unknown environments

    Directory of Open Access Journals (Sweden)

    Lobo Pereira Fernando

    2010-02-01

    Full Text Available Abstract Background The combination of robotic tools with assistance technology determines a slightly explored area of applications and advantages for disability or elder people in their daily tasks. Autonomous motorized wheelchair navigation inside an environment, behaviour based control of orthopaedic arms or user's preference learning from a friendly interface are some examples of this new field. In this paper, a Simultaneous Localization and Mapping (SLAM algorithm is implemented to allow the environmental learning by a mobile robot while its navigation is governed by electromyographic signals. The entire system is part autonomous and part user-decision dependent (semi-autonomous. The environmental learning executed by the SLAM algorithm and the low level behaviour-based reactions of the mobile robot are robotic autonomous tasks, whereas the mobile robot navigation inside an environment is commanded by a Muscle-Computer Interface (MCI. Methods In this paper, a sequential Extended Kalman Filter (EKF feature-based SLAM algorithm is implemented. The features correspond to lines and corners -concave and convex- of the environment. From the SLAM architecture, a global metric map of the environment is derived. The electromyographic signals that command the robot's movements can be adapted to the patient's disabilities. For mobile robot navigation purposes, five commands were obtained from the MCI: turn to the left, turn to the right, stop, start and exit. A kinematic controller to control the mobile robot was implemented. A low level behavior strategy was also implemented to avoid robot's collisions with the environment and moving agents. Results The entire system was tested in a population of seven volunteers: three elder, two below-elbow amputees and two young normally limbed patients. The experiments were performed within a closed low dynamic environment. Subjects took an average time of 35 minutes to navigate the environment and to learn how

  12. SLAM algorithm applied to robotics assistance for navigation in unknown environments.

    Science.gov (United States)

    Cheein, Fernando A Auat; Lopez, Natalia; Soria, Carlos M; di Sciascio, Fernando A; Pereira, Fernando Lobo; Carelli, Ricardo

    2010-02-17

    The combination of robotic tools with assistance technology determines a slightly explored area of applications and advantages for disability or elder people in their daily tasks. Autonomous motorized wheelchair navigation inside an environment, behaviour based control of orthopaedic arms or user's preference learning from a friendly interface are some examples of this new field. In this paper, a Simultaneous Localization and Mapping (SLAM) algorithm is implemented to allow the environmental learning by a mobile robot while its navigation is governed by electromyographic signals. The entire system is part autonomous and part user-decision dependent (semi-autonomous). The environmental learning executed by the SLAM algorithm and the low level behaviour-based reactions of the mobile robot are robotic autonomous tasks, whereas the mobile robot navigation inside an environment is commanded by a Muscle-Computer Interface (MCI). In this paper, a sequential Extended Kalman Filter (EKF) feature-based SLAM algorithm is implemented. The features correspond to lines and corners -concave and convex- of the environment. From the SLAM architecture, a global metric map of the environment is derived. The electromyographic signals that command the robot's movements can be adapted to the patient's disabilities. For mobile robot navigation purposes, five commands were obtained from the MCI: turn to the left, turn to the right, stop, start and exit. A kinematic controller to control the mobile robot was implemented. A low level behavior strategy was also implemented to avoid robot's collisions with the environment and moving agents. The entire system was tested in a population of seven volunteers: three elder, two below-elbow amputees and two young normally limbed patients. The experiments were performed within a closed low dynamic environment. Subjects took an average time of 35 minutes to navigate the environment and to learn how to use the MCI. The SLAM results have shown a

  13. A Movement-Assisted Deployment of Collaborating Autonomous Sensors for Indoor and Outdoor Environment Monitoring.

    Science.gov (United States)

    Niewiadomska-Szynkiewicz, Ewa; Sikora, Andrzej; Marks, Michał

    2016-09-14

    Using mobile robots or unmanned vehicles to assist optimal wireless sensors deployment in a working space can significantly enhance the capability to investigate unknown environments. This paper addresses the issues of the application of numerical optimization and computer simulation techniques to on-line calculation of a wireless sensor network topology for monitoring and tracking purposes. We focus on the design of a self-organizing and collaborative mobile network that enables a continuous data transmission to the data sink (base station) and automatically adapts its behavior to changes in the environment to achieve a common goal. The pre-defined and self-configuring approaches to the mobile-based deployment of sensors are compared and discussed. A family of novel algorithms for the optimal placement of mobile wireless devices for permanent monitoring of indoor and outdoor dynamic environments is described. They employ a network connectivity-maintaining mobility model utilizing the concept of the virtual potential function for calculating the motion trajectories of platforms carrying sensors. Their quality and utility have been justified through simulation experiments and are discussed in the final part of the paper.

  14. A Movement-Assisted Deployment of Collaborating Autonomous Sensors for Indoor and Outdoor Environment Monitoring

    Directory of Open Access Journals (Sweden)

    Ewa Niewiadomska-Szynkiewicz

    2016-09-01

    Full Text Available Using mobile robots or unmanned vehicles to assist optimal wireless sensors deployment in a working space can significantly enhance the capability to investigate unknown environments. This paper addresses the issues of the application of numerical optimization and computer simulation techniques to on-line calculation of a wireless sensor network topology for monitoring and tracking purposes. We focus on the design of a self-organizing and collaborative mobile network that enables a continuous data transmission to the data sink (base station and automatically adapts its behavior to changes in the environment to achieve a common goal. The pre-defined and self-configuring approaches to the mobile-based deployment of sensors are compared and discussed. A family of novel algorithms for the optimal placement of mobile wireless devices for permanent monitoring of indoor and outdoor dynamic environments is described. They employ a network connectivity-maintaining mobility model utilizing the concept of the virtual potential function for calculating the motion trajectories of platforms carrying sensors. Their quality and utility have been justified through simulation experiments and are discussed in the final part of the paper.

  15. GALE: a graphics assisted learning environment for computer-based interactive videodisc education.

    Science.gov (United States)

    Cutts, J H; Hazelwood, S E; Mitchell, J A; Bridges, A J; Reid, J C

    1992-08-01

    GALE, a Graphics Assisted Learning Environment, is a computer-based interactive videodisc authoring tool. GALE was created as the authoring package for AI/LEARN/Rheumatology, an independent study system for teaching rheumatology to medical trainees. GALE has potential widespread application beyond rheumatology. Interactive videodisc technology is a prime feature of GALE. Other highlights are: WordPerfect macros which simplify programming, graphics-based large text characters, tracking of user responses, hypertext-like definition capabilities, color coded screens to distinguish between hypertext branches and the mainstream of the course content and ability to overlay text on the video image. GALE runs on a PC-compatible computer with selected Pioneer LaserDisc players. GALE uses WordPerfect 5.1 for text editing and has been designed for use by non-programmers.

  16. A Beowulf Class parallel remote-sensed image database retrieval system developed in ASSIST environment

    Science.gov (United States)

    Di Lecce, Vincenzo; Guerriero, Andrea; Guarino, I.

    2005-01-01

    Image databases are now currently utilized in a wide range of different areas, in particular, the development and application of remote sensing platforms result in the production of huge amounts of image data. One of the major problem in the practical implementation of a Content-based Image Retrieval (CBIR) for remotely sensed images is that the content-based indexing and searching process always requires extremely high computational power. On the other hand, the content-based image retrieval algorithms are very suitable for parallel computation as the algorithms can be broken into several data independent processes for running on a parallel computer. In this paper, we discuss the porting problem of a sequential application of remote sensed image retrieval in a parallel environment using the new paradigm of programming introduced by the birth of a new structured program languages (Assist 1.2) and compared performances to sequential and to commercial multiprocessors solutions.

  17. Context management: toward assessing quality of context parameters in a ubiquitous ambient assisted living environment

    Directory of Open Access Journals (Sweden)

    Débora Cabral Nazário

    2015-09-01

    Full Text Available This paper provides an approach to assessing Quality of Context (QoC parameters in a ubiquitous Ambient Assisted Living (AAL environment. Initially, the study presents a literature review on QoC, generating taxonomy. Then it introduces the context management architecture used. The proposal is verified with the Siafu simulator in an AAL scenario where the user’s health is monitored with information about blood pressure, heart rate and body temperature. Considering some parameters, the proposed QoC assessment allows verifying the extent to which the context information is up-to-date, valid, accurate, complete and significant. The implementation of this proposal might mean a big social impact and a technological innovation applied to AAL, at the disposal and support of a significant number of individuals such as elderly or sick people, and with a more precise technology.

  18. An Internet of Things platform architecture for supporting ambient assisted living environments.

    Science.gov (United States)

    Tsirmpas, Charalampos; Kouris, Ioannis; Anastasiou, Athanasios; Giokas, Kostas; Iliopoulou, Dimitra; Koutsouris, Dimitris

    2017-01-01

    Internet of Things (IoT) is the logical further development of today's Internet, enabling a huge amount of devices to communicate, compute, sense and act. IoT sensors placed in Ambient Assisted Living (AAL) environments, enable the context awareness and allow the support of the elderly in their daily routines, ultimately allowing an independent and safe lifestyle. The vast amount of data that are generated and exchanged between the IoT nodes require innovative context modeling approaches that go beyond currently used models. Current paper presents and evaluates an open interoperable platform architecture in order to utilize the technical characteristics of IoT and handle the large amount of generated data, as a solution to the technical requirements of AAL applications.

  19. High sensitivity hydrogen sensing with Pt-decorated porous gallium nitride prepared by metal-assisted electroless etching.

    Science.gov (United States)

    Duan, Barrett K; Bohn, Paul W

    2010-05-01

    A unique hydrogen sensor structure based on Pt-decorated porous gallium nitride (PGaN) was fabricated by a two-step process consisting of metal-assisted electroless etching to produce PGaN with highly anisotropic pores followed by electroless deposition of Pt in the pores from an ammoniacal PtCl(6)(2-) solution. The Pt-decorated PGaN structure contains 50-100 nm diameter nanopores which are 400 nm to 1 microm deep and filled with Pt islands. Both electroless etching and deposition steps are done in solution and allow for large-scale production. An AC four-point probe conductivity measurement was implemented at f = 1 kHz, a frequency where the impedance of Pt-PGaN is nearly entirely resistive, and the change in conductance upon H(2) exposure was measured for three sample types: PGaN with a surface sputtered layer of Pt only; unetched GaN (CGaN) with both sputtered and electrolessly deposited Pt; and PGaN with both sputtered and electrolessly deposited Pt. The hydrogen sensing performance of the Pt-filled PGaN sensor was more than an order of magnitude better than either of the other two sample types under all experimental conditions, an observation attributed to the significant increase in Pt-GaN interfacial area in the electrolessly decorated PGaN samples, exhibiting a response to H2 concentrations as low as 1 ppm. The conductance changes are ascribed to adsorption-induced changes in interfacial polarization that produce changes in band bending and thus to the width of the space charge region near the Pt-GaN interface.

  20. Hydrogen isotope composition of natural gases from the Tarim Basin and its indication of depositional environments of the source rocks

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By measuring carbon and hydrogen isotope compositions for C1, C2 and C3 of 74 gas samples, natural gases from the Tarim Basin can be divided into six groups on the basis of their origins: (1) coal-type gas derived from coal measures; (2) coal-type gas generated from the T-J lacustrine mudstones; (3) oil-type gas derived from the Cambrian and low Ordovician marine source rocks; (4) oil-type gas from the source rocks deposited in the marine-transitional facies; (5) mixing gas between gas derived from the Carboniferous transitional source rocks and the Mesozoic humic gas, and (6) mixing gases of thermal genetic gas and little deep gas in the Southwest depression of the Tarim Basin. The δ D values of methane in natural gases originating from different type kerogens are affected by both palaeo-environments of the source rock formation (kerogen types) and thermal maturity, with sedimentary environment (kerogen type) as the main controlling factor. Under the similar thermal maturity, the hydrogen isotope composition of methane is more enriched in deuterium in marine environments than lacustrine one. With the increase of thermal maturity and the increase of carbon atomic numbers of gaseous alkanes, the hydrogen isotopes become enriched in deuterium. The δ D values of ethane and propane (δ D2, δ D3) are controlled mainly by thermal maturity and to a lesser degree by sedimentary environment of the source rock formation. The partial reversal of hydrogen isotopes for gaseous alkanes would be related to the microbial oxidation, mixing of sapropelic and humic gases and / or mixing of gases from similar kerogen sources with various thermal maturities. In the oil-type gas, the sulfate reduction reaction would result in the reversed order of δ D1 and δ D2 (e.g. δ D1>δ D2).

  1. Stability of MOF-5 in a hydrogen gas environment containing fueling station impurities

    DEFF Research Database (Denmark)

    Ming, Yang; Purewal, Justin; Yang, Jun

    2016-01-01

    Metal-organic frameworks (MOFs) are an emerging class of porous, crystalline materials with potential application as hydrogen storage media in fuel cell vehicles. Unlike lower capacity adsorbents such as zeolites and carbons, some MOFs are expected to degrade due to attack by impurities present...... capacity of an exposed sample. Hydrogen chloride was observed to be the only impurity that yielded a measurable, albeit small, decrease in hydrogen capacity; no change in H2 uptake was observed for the other impurities. Post-cycling and post-storage MOF-5 samples were also analyzed using infrared...

  2. Ligand assisted carbon dioxide activation and hydrogenation using molybdenum and tungsten amides.

    Science.gov (United States)

    Chakraborty, Subrata; Blacque, Olivier; Berke, Heinz

    2015-04-14

    The hepta-coordinated isomeric M(NO)Cl3(PN(H)P) complexes {M = Mo, ; W, , PN(H)P = (iPr2PCH2CH2)2NH, (HN atom of PN(H)P syn and anti to the NO ligand)} and the paramagnetic species M(NO)Cl2(PN(H)P) (M = Mo, ; W, ) could be prepared via a new synthetic pathway. The pseudo trigonal bipyramidal amides M(NO)(CO)(PNP) {M = Mo, ; W, ; [PNP](-) = [(iPr2PCH2CH2)2N](-)} were reacted with CO2 at room temperature with CO2 approaching the M[double bond, length as m-dash]N double bond in the equatorial (CO,NO,N) plane trans to the NO ligand and forming the pseudo-octahedral cyclic carbamates M(NO)(CO)(PNP)(OCO) (M = Mo, ; W = ). DFT calculations revealed that the approach to form the isomer is kinetically determined. The amine hydrides M(NO)H(CO)(PN(H)P) {M = Mo, ; W, }, obtained by H2 addition to , insert CO2 (2 bar) at room temperature into the M-H bond generating isomeric mixtures of the η(1)-formato complexes M(NO)(CO)(PN(H)P)(η(1)-OCHO), (M = Mo, ; M = W, ). Closing the stoichiometric cycles for sodium formate formation the isomeric mixtures were reacted with 1 equiv. of Na[N(SiMe3)2] regenerating . Attempts to turn the stoichiometric formate production into catalytic CO2 hydrogenation using in the presence of various types of sterically congested bases furnished yields of formate salts of up to 4%.

  3. Investigation of Laser Peening Effects on Hydrogen Charged Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Zaleski, Tania M. [San Jose State Univ., CA (United States)

    2008-10-30

    Hydrogen-rich environments such as fuel cell reactors can exhibit damage caused by hydrogen permeation in the form of corrosion cracking by lowering tensile strength and decreasing material ductility. Coatings and liners have been investigated, but there were few shot-peening or laser peening studies referenced in the literature with respect to preventing hydrogen embrittlement. The surface compressive residual stress induced by laser peening had shown success in preventing stress corrosion cracking (SCC) for stainless steels in power plants. The question arose if the residual stresses induced by laser peening could delay the effects of hydrogen in a material. This study investigated the effect of laser peening on hydrogen penetration into metal alloys. Three areas were studied: laser peening, hydrogenation, and hydrogen detection. This study demonstrated that laser peening does not reduce the hydrogen permeation into a stainless steel surface nor does it prevent hydrogen embrittlement. The effect of laser peening to reduce hydrogen-assisted fatigue was unclear.

  4. Mechanistic study on ultrasound assisted pretreatment of sugarcane bagasse using metal salt with hydrogen peroxide for bioethanol production.

    Science.gov (United States)

    Ramadoss, Govindarajan; Muthukumar, Karuppan

    2016-01-01

    This study presents the ultrasound assisted pretreatment of sugarcane bagasse (SCB) using metal salt with hydrogen peroxide for bioethanol production. Among the different metal salts used, maximum holocellulose recovery and delignification were achieved with ultrasound assisted titanium dioxide (TiO2) pretreatment (UATP) system. At optimum conditions (1% H2O2, 4 g SCB dosage, 60 min sonication time, 2:100 M ratio of metal salt and H2O2, 75°C, 50% ultrasound amplitude and 70% ultrasound duty cycle), 94.98 ± 1.11% holocellulose recovery and 78.72 ± 0.86% delignification were observed. The pretreated SCB was subjected to dilute acid hydrolysis using 0.25% H2SO4 and maximum xylose, glucose and arabinose concentration obtained were 10.94 ± 0.35 g/L, 14.86 ± 0.12 g/L and 2.52 ± 0.27 g/L, respectively. The inhibitors production was found to be very less (0.93 ± 0.11 g/L furfural and 0.76 ± 0.62 g/L acetic acid) and the maximum theoretical yield of glucose and hemicellulose conversion attained were 85.8% and 77%, respectively. The fermentation was carried out using Saccharomyces cerevisiae and at the end of 72 h, 0.468 g bioethanol/g holocellulose was achieved. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis of pretreated SCB was made and its morphology was studied using scanning electron microscopy (SEM). The compounds formed during the pretreatment were identified using gas chromatography-mass spectrometry (GC-MS) analysis.

  5. [Study of hydrogen cyanide activity in various working environment in gold-mining industry].

    Science.gov (United States)

    Dedkova, L A; Dorogova, V B; Petrov, V F

    2008-01-01

    The study concerned an influence of saline content of liquid phase of crushed ore and presence or absence of solution blending on the process of cyanic hydrogen release in air of working area gold-mining industry.

  6. Neighboring Hetero-Atom Assistance of Sacrificial Amines to Hydrogen Evolution Using Pt-Loaded TiO2-Photocatalyst

    Directory of Open Access Journals (Sweden)

    Masahide Yasuda

    2014-05-01

    Full Text Available Photocatalytic H2 evolution was examined using Pt-loaded TiO2-photocatalyst in the presence of amines as sacrificial agents. In the case of amines with all of the carbon attached to the hetero-atom such as 2-aminoethanol, 1,2-diamonoethane, 2-amino-1,3-propanediol, and 3-amino-1,2-propanediol, they were completely decomposed into CO2 and water to quantitatively evolve H2. On the other hand, the amines with both hetero-atoms and one methyl group at the β-positions (neighboring carbons of amino group such as 2-amino-1-propanol and 1,2-diaminopropane were partially decomposed. Also, the photocatalytic H2 evolution using amines without the hetero-atoms at the β-positions such as ethylamine, propylamine, 1-butylamine, 1,3-diaminopropane, 2-propylamine, and 2-butylamine was inefficient. Thus, it was found that the neighboring hetero-atom strongly assisted the degradation of sacrificial amines. Moreover, rate constants for H2 evolution were compared among amines. In conclusion, the neighboring hetero-atom did not affect the rate constants but enhanced the yield of hydrogen evolution.

  7. Supercritical carbon dioxide-assisted rapid synthesis of few-layer black phosphorus for hydrogen peroxide sensing.

    Science.gov (United States)

    Yan, Shancheng; Wang, Bojun; Wang, Zhulan; Hu, Dong; Xu, Xin; Wang, Junzhuan; Shi, Yi

    2016-06-15

    Solutions with large-scale dispersions of 2D black phosphorus (BP), often referred to as phosphorene, are obtained through solvent exfoliation. But, rapid phosphorene synthesis remains a challenge. Furthermore, although the chemical sensing capability of BP-based sensors has been theoretically predicted, its experimental verification remains lacking. In this study, we demonstrate the use of supercritical carbon dioxide-assisted rapid synthesis (5h) of few-layer BP. In addition, we construct a non-enzymatic hydrogen peroxide (H2O2) sensor based on few-layer BP for the first time to utilize BP degradation under ambient conditions. The proposed H2O2 sensor exhibits a considerably lower detection limit of 1 × 10(-7) M compared with the general detection limit of 1 × 10(-7) M-5 × 10(-5)M via electrochemical methods. Overall, the results of this study will not only expand the coverage of BP research but will also identify the important sensing characteristics of BP.

  8. Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

    Science.gov (United States)

    Rozenak, Paul; Unigovski, Yaakov; Shneck, Roni

    2016-05-01

    The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M23C6) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

  9. Hydrogen Peroxide Cycling in Acidic Geothermal Environments and Potential Implications for Oxidative Stress

    Science.gov (United States)

    Mesle, M.; Beam, J.; Jay, Z.; Bodle, B.; Bogenschutz, E.; Inskeep, W.

    2014-12-01

    Hydrogen peroxide (H2O2) may be produced in natural waters via photochemical reactions between dissolved oxygen, organic carbon and light. Other reactive oxygen species (ROS) such as superoxide and hydroxyl radicals are potentially formed in environments with high concentrations of ferrous iron (Fe(II), ~10-100 μM) by reaction between H2O2 and Fe(II) (i.e., Fenton chemistry). Thermophilic archaea and bacteria inhabiting acidic iron-oxide mats have defense mechanisms against both extracellular and intracellular peroxide, such as peroxiredoxins (which can degrade H2O2) and against other ROS, such as superoxide dismutases. Biological cycling of H2O2 is not well understood in geothermal ecosystems, and geochemical measurements combined with molecular investigations will contribute to our understanding of microbial response to oxidative stress. We measured H2O2 and other dissolved compounds (Fe(II), Fe(III), H2S, O2), as well as photon flux, pH and temperature, over time in surface geothermal waters of several acidic springs in Norris Geyser Basin, Yellowstone National Park, WY (Beowulf Spring and One Hundred Spring Plain). Iron-oxide mats were sampled in Beowulf Spring for on-going analysis of metatranscriptomes and RT-qPCR assays of specific stress-response gene transcription (e.g., superoxide dismutases, peroxiredoxins, thioredoxins, and peroxidases). In situ analyses show that H2O2 concentrations are lowest in the source waters of sulfidic systems (ca. 1 μM), and increase by two-fold in oxygenated waters corresponding to Fe(III)-oxide mat formation (ca. 2 - 3 μM). Channel transects confirm increases in H2O2 as a function of oxygenation (distance). The temporal dynamics of H2O2, O2, Fe(II), and H2S in Beowulf geothermal waters were also measured during a diel cycle, and increases in H2O2 were observed during peak photon flux. These results suggest that photochemical reactions may contribute to changes in H2O2. We hypothesize that increases in H2O2 and O2

  10. Comparison of the Effects of Fluidized-Bed and Fixed-Bed Reactors in Microwave-Assisted Catalytic Decomposition of TCE by Hydrogen

    Directory of Open Access Journals (Sweden)

    Lili Ren

    2012-01-01

    Full Text Available Trichloroethylene (TCE decomposition by hydrogen with microwave heating under different reaction systems was investigated. The activities of a series of catalysts for microwave-assisted TCE hydrodechlorination were tested through the fixed-bed and the fluidized-bed reactor systems. This study found that the different reaction system is suitable for different catalyst type. And there is an interactive relationship between the catalyst type and the reaction bed type.

  11. Pacific Northwest Laboratory annual report for 1987 to the Assistant Secretary for Environment, Safety, and Health: Part 5: Environment, safety, health, and quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Faust, L.G.; Steelman, B.L.; Selby, J.M.

    1988-02-01

    Part 5 of the 1987 Annual Report to the US Department of Energy's Assistant Secretary for Environment, Safety, and Health presents Pacific Northwest Laboratory's progress on work performed for the Office of Nuclear Safety, the Office of Environmental Guidance and Compliance, the Office of Environmental Audit, and the Office of National Environmental Policy Act Project Assistance. For each project, as identified by the Field Work Proposal, articles describe progress made during fiscal year 1987. Authors of these articles represent a broad spectrum of capabilities derived from five of the seven technical centers of the Laboratory, reflecting the interdisciplinary nature of the work.

  12. Learning English Vocabulary in a Mobile Assisted Language Learning (MALL) Environment: A Sociocultural Study of Migrant Women

    Science.gov (United States)

    Ahmad, Kham Sila; Sudweeks, Fay; Armarego, Jocelyn

    2015-01-01

    This paper reports on a case study of a group of six non-native English speaking migrant women's experiences learning English vocabulary in a mobile assisted language learning (MALL) environment at a small community centre in Western Australia. A sociocultural approach to learning vocabulary was adopted in designing the MALL lessons that the women…

  13. The Effect of a Graph-Oriented Computer-Assisted Project-Based Learning Environment on Argumentation Skills

    Science.gov (United States)

    Hsu, P. -S.; Van Dyke, M.; Chen, Y.; Smith, T. J.

    2015-01-01

    The purpose of this quasi-experimental study was to explore how seventh graders in a suburban school in the United States developed argumentation skills and science knowledge in a project-based learning environment that incorporated a graph-oriented, computer-assisted application. A total of 54 students (three classes) comprised this treatment…

  14. The Effect of a Graph-Oriented Computer-Assisted Project-Based Learning Environment on Argumentation Skills

    Science.gov (United States)

    Hsu, P. -S.; Van Dyke, M.; Chen, Y.; Smith, T. J.

    2015-01-01

    The purpose of this quasi-experimental study was to explore how seventh graders in a suburban school in the United States developed argumentation skills and science knowledge in a project-based learning environment that incorporated a graph-oriented, computer-assisted application. A total of 54 students (three classes) comprised this treatment…

  15. Pacific Northwest Laboratory annual report for 1980 to the DOE Assistant Secretary for Environment. Part 2 supplement, ecological sciences

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, B.E.

    1981-06-01

    This supplement replaces the list of Publications and Presentations in the Pacific Northwest Laboratory Annual Report for 1980 to the Assistant Secretary for Environment, PNL-3700 PT2, Ecological Sciences. The listings in the report as previously distributed were incomplete owing to changeovers in the bibliographic-tracking system.

  16. Charged particle assisted nuclear reactions in solid state environment: renaissance of low energy nuclear physics

    CERN Document Server

    Kálmán, Péter

    2015-01-01

    The features of electron assisted neutron exchange processes in crystalline solids are survayed. It is stated that, contrary to expectations, the cross section of these processes may reach an observable magnitude even in the very low energy case because of the extremely huge increment caused by the Coulomb factor of the electron assisted processes and by the effect of the crystal-lattice. The features of electron assisted heavy charged particle exchange processes, electron assisted nuclear capure processes and heavy charged particle assisted nuclear processes are also overviewed. Experimental observations, which may be related to our theoretical findings, are dealt with. The anomalous screening phenomenon is related to electron assisted neutron and proton exchange processes in crystalline solids. A possible explanation of observations by Fleischmann and Pons is presented. The possibility of the phenomenon of nuclear transmutation is qualitatively explained with the aid of usual and charged particle assisted r...

  17. Susceptibility of Alloy 22 to Environmentally Assisted Cracking in Yucca Mountain Relevant Environments

    Energy Technology Data Exchange (ETDEWEB)

    Estill, J C; King, K J; Fix, D V; Spurlock, D G; Hust, G A; Gordon, S R; McCright, R D; Rebak, R B; Gordon, G M

    2002-01-30

    In its current design, the high level nuclear waste containers will include an external layer of Alloy 22 (Ni-22Cr-13Mo-3W-3Fe). Since over their life-time the containers may be exposed to multi-ionic aqueous environments, a potential degradation mode of the outer layer could be environmental assisted cracking (EAC). The objective of the current research work was to quantify the susceptibility of Alloy 22 to EAC in a several environmental conditions including solution composition, temperature and electrochemical potential. The susceptibility to EAC was evaluated using the constant deformation technique, the compact specimen--low cycle fatigue method and the slow strain rate test (SSRT). The alloy was tested in the wrought mill annealed (MA) and in the as-welded conditions. Results show that Alloy 22 was extremely resistant to EAC in a wide range of environmental conditions. Using SSRT, Alloy 22 was found susceptible to EAC in one electrolyte at one temperature and at one electrochemical potential.

  18. Coal Ash Behavior in Reducing Environments (CABRE) III Year 6 - Activity 1.10 - Development of a National Center for Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, Joshua; Azenkeng, Alexander; McCollor, Donald; Galbreath, Kevin; Jensen, Robert; Lahr, Brent

    2012-03-31

    The Energy & Environmental Research Center (EERC) has been conducting research on gasification for six decades. One of the objectives of this gasification research has been to maximize carbon conversion and the water–gas shift process for optimal hydrogen production and syngas quality. This research focus and experience were a perfect fit for the National Center for Hydrogen Technology ® (NCHT®) Program at the EERC for improving all aspects of coal gasification, which ultimately aids in the production and purification of hydrogen. A consortia project was developed under the NCHT Program to develop an improved predictive model for ash formation and deposition under the project entitled “Coal Ash Behavior in Reducing Environments (CABRE) III: Development of the CABRE III Model.” The computer-based program is now applicable to the modeling of coal and ash behavior in both entrained-flow and fluidized-bed gasification systems to aid in overall gasification efficiency. This model represents a significant improvement over the CABRE II model and runs on a Microsoft Windows PC platform. The major achievements of the CABRE III model are partitioning of inorganic transformations between various phases for specific gas cleanup equipment; slag property predictions, including standard temperature–viscosity curves and slag flow and thickness; deposition rates in gasification cleanup equipment; provision for composition analysis for all input and output streams across all process equipment, including major elements and trace elements of interest; composition analysis of deposit streams for various deposit zones, including direct condensation on equipment surfaces (Zone A), homogeneous particulate deposition (Zone B), and entrained fly ash deposition (Zone C); and physical removal of ash in cyclones based on D50 cut points. Another new feature of the CABRE III model is a user-friendly interface and detailed reports that are easily exportable into Word documents, Excel

  19. Irradiation-Assisted Stress Corrosion Cracking of Austenitic Stainless Steels in BWR Environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Chopra, O. K. [Argonne National Lab. (ANL), Argonne, IL (United States); Gruber, Eugene E. [Argonne National Lab. (ANL), Argonne, IL (United States); Shack, William J. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2010-06-01

    The internal components of light water reactors are exposed to high-energy neutron irradiation and high-temperature reactor coolant. The exposure to neutron irradiation increases the susceptibility of austenitic stainless steels (SSs) to stress corrosion cracking (SCC) because of the elevated corrosion potential of the reactor coolant and the introduction of new embrittlement mechanisms through radiation damage. Various nonsensitized SSs and nickel alloys have been found to be prone to intergranular cracking after extended neutron exposure. Such cracks have been seen in a number of internal components in boiling water reactors (BWRs). The elevated susceptibility to SCC in irradiated materials, commonly referred to as irradiation-assisted stress corrosion cracking (IASCC), is a complex phenomenon that involves simultaneous actions of irradiation, stress, and corrosion. In recent years, as nuclear power plants have aged and irradiation dose increased, IASCC has become an increasingly important issue. Post-irradiation crack growth rate and fracture toughness tests have been performed to provide data and technical support for the NRC to address various issues related to aging degradation of reactor-core internal structures and components. This report summarizes the results of the last group of tests on compact tension specimens from the Halden-II irradiation. The IASCC susceptibility of austenitic SSs and heat-affected-zone (HAZ) materials sectioned from submerged arc and shielded metal arc welds was evaluated by conducting crack growth rate and fracture toughness tests in a simulated BWR environment. The fracture and cracking behavior of HAZ materials, thermally sensitized SSs and grain-boundary engineered SSs was investigated at several doses (≤3 dpa). These latest results were combined with previous results from Halden-I and II irradiations to analyze the effects of neutron dose, water chemistry, alloy compositions, and welding and processing conditions on IASCC

  20. Microsensors based on a whispering gallery mode in AlGaN microdisks undercut by hydrogen-environment thermal etching.

    Science.gov (United States)

    Kouno, Tetsuya; Sakai, Masaru; Takeshima, Hoshi; Suzuki, Sho; Kikuchi, Akihiko; Kishino, Katsumi; Hara, Kazuhiko

    2017-04-20

    AlGaN microdisks were fabricated via a top-down process using electron-beam lithography, inductively coupled plasma reactive-ion etching, and hydrogen-environment thermal etching from commercial epitaxial wafers with a 100-300 nm thick AlGaN layer grown on a c-plane GaN layer by metal-organic chemical vapor deposition. The hydrogen-environment thermal etching performed well in undercutting the AlGaN microdisks owing to the selective etching for the GaN layer. The AlGaN microdisks acted as the whispering gallery mode (WGM) optical microresonators, exhibiting sharp resonant peaks in room temperature photoluminescence spectra. The evanescent component of the whispering gallery mode (WGM) is influenced by the ambient condition of the microdisk, resulting in the shift of the resonant peaks. The phenomenon is considered to be used for microsensors. Using the WGM in the AlGaN microdisks, we demonstrated microsensors and a microsensor system, which can potentially be used to evaluate biological and chemical actions in a microscale area in real time.

  1. Hydrogen production by steam reforming of bio-alcohols. The use of conventional and membrane-assisted catalytic reactors

    Energy Technology Data Exchange (ETDEWEB)

    Seelam, P. K.

    2013-11-01

    The energy consumption around the globe is on the rise due to the exponential population growth and urbanization. There is a need for alternative and non-conventional energy sources, which are CO{sub 2}-neutral, and a need to produce less or no environmental pollutants and to have high energy efficiency. One of the alternative approaches is hydrogen economy with the fuel cell (FC) technology which is forecasted to lead to a sustainable society. Hydrogen (H{sub 2}) is recognized as a potential fuel and clean energy carrier being at the same time a carbon-free element. Moreover, H{sub 2} is utilized in many processes in chemical, food, metallurgical, and pharmaceutical industry and it is also a valuable chemical in many reactions (e.g. refineries). Non-renewable resources have been the major feedstock for H{sub 2} production for many years. At present, {approx}50% of H{sub 2} is produced via catalytic steam reforming of natural gas followed by various down-stream purification steps to produce {approx}99.99% H{sub 2}, the process being highly energy intensive. Henceforth, bio-fuels like biomass derived alcohols (e.g. bio-ethanol and bio-glycerol), can be viable raw materials for the H{sub 2} production. In a membrane based reactor, the reaction and selective separation of H{sub 2} occur simultaneously in one unit, thus improving the overall reactor efficiency. The main motivation of this work is to produce H{sub 2} more efficiently and in an environmentally friendly way from bio-alcohols with a high H{sub 2} selectivity, purity and yield. In this thesis, the work was divided into two research areas, the first being the catalytic studies using metal decorated carbon nanotube (CNT) based catalysts in steam reforming of ethanol (SRE) at low temperatures (<450 deg C). The second part was the study of steam reforming (SR) and the water-gas-shift (WGS) reactions in a membrane reactor (MR) using dense and composite Pd-based membranes to produce high purity H{sub 2}. CNTs

  2. Tungsten dust nanoparticles generation from blistering bursts under hydrogen environment in microwave ECR discharge

    Energy Technology Data Exchange (ETDEWEB)

    Ouaras, K., E-mail: ouaras@lspm.cnrs.fr; Hassouni, K.; Delacqua, L. Colina; Lombardi, G.; Vrel, D.; Bonnin, X.

    2015-11-15

    Blistering burst induced tungsten dust nanoparticles were observed for the first time when a tungsten sample is submitted to a hydrogen low-temperature discharge under low flux and low incident energy values (20, 120 and 220 eV) at a surface temperature of 500 K. Tungsten nanoparticles (∼50 nm) were organized in 2D domains with diameter that is well correlated to the blister volume losses by burst. These observations suggest that dust nanoparticles were generated from blistering burst.

  3. Materials for high-temperature hydrogen fluorine environments. Final report, June 1976-December 1978

    Energy Technology Data Exchange (ETDEWEB)

    Holcombe, C.E. Jr.; Kovach, L.

    1981-03-01

    A determination has been made of the stability of 35 materials under high-temperature, fluorine rich, hydrogen fluoride torch testing. Refractory materials tested included 4 borides, 3 carbides, 3 nitrides, 12 oxides, 1 oxynitride, 1 sulfide, 10 metals, and carbon (10 types). Three materials distinctly performed better than nickel: lanthanum hexaboride, calcium hexaboride, and lanthanum silicon oxynitride. Of these, lanthanum hexaboride is the best candidate tested since it has an estimated upper use temperature > 1726 K, which is above the melting point and more than 300 K above the upper use temperature of nickel.

  4. In-Class Extensive Reading Activity to Assist Self-Paced Learning in a Large Class-Size Environment

    OpenAIRE

    鬼田, 崇作

    2013-01-01

    The purpose of this paper is to show the effects an extensive reading activity had in assisting students in a self-paced learning, large class-size English environment. As the student body was diverse, encompassing varying levels of ability, learning styles, interests and proficiency, it is essential that teachers pay attention to these differences and adapt the materials to each learner's individual differences. However, it is difficult for a teacher to satisfy all of their individual studen...

  5. Use of workflow technology to assist remote caretakers in a smart kitchen environment designed for elderly people suffering from dementia

    OpenAIRE

    Sarni, T. (Tomi)

    2013-01-01

    Purpose of this study was to determine feasibility of an information system that enables remote assistance between caretakers and elderly people suffering from dementia in a smart kitchen environment. Such system could alleviate stress experienced by caretakers by enabling provisioning of care giving between any combination of informal and formal caretakers, and by increasing mobility of caretakers. Second research problem was to evaluate benefits and drawbacks of using workflow technology to...

  6. Enhancement of fermentative hydrogen production in an extreme-thermophilic (70°C) mixed-culture environment by repeated batch cultivation.

    Science.gov (United States)

    Lu, Wenjing; Fan, Gaoyuan; Zhao, Chenxi; Wang, Hongtao; Chi, Zifang

    2012-05-01

    Repeated batch cultivation was applied to enrich hydrogen fermentative microflora under extreme-thermophilic (70°C) environment. Initial inoculums received from a hydrogen producing reactor fed with organic fraction of household solid wastes. In total seven transfers was conducted and maximum hydrogen yield reached 296 ml H(2)/g (2.38 mol/mol) glucose and 252 ml H(2)/g (2.03 mol/mol) for 1 and 2 g/l glucose medium, respectively. It was found that hydrogen production was firstly decreased and got increased gradually from third generation. Acetate was found to be the main metabolic by-product in all batch cultivation. Furthermore, the diversity of bacterial community got decreased after repeated batch cultivation. It was proved that repeated batch cultivation was a good method to enhance the hydrogen production by enriching the mixed cultures of dominant species.

  7. Pacific Northwest Laboratory annual report for 1989 to the Assistant Secretary for Environment, Safety, and Health - Part 5: Environment, Safety, Health, and Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    Faust, L.G.; Doctor, P.G.; Selby, J.M.

    1990-04-01

    Part 5 of the 1989 Annual Report to the US Department of Energy's Assistant Secretary for Environment, Safety, and Health presents Pacific Northwest Laboratory's progress on work performed for the Office of Environmental Guidance and Compliance, the Office of Environmental Audit, the Office of National Environmental Policy Act Project Assistance, the Office of Nuclear Safety, the Office of Safety Compliance, and the Office of Policy and Standards. For each project, as identified by the Field Work Proposal, there is an article describing progress made during fiscal year 1989. Authors of these articles represent a broad spectrum of capabilities derived from five of the seven technical centers of the Laboratory, reflecting the interdisciplinary nature of the work. 35 refs., 1 fig.

  8. Pulsed laser deposition-assisted synthesis of porous WP2 nanosheet arrays integrated on graphite paper as a 3D flexible cathode for efficient hydrogen evolution

    Science.gov (United States)

    Pi, Mingyu; Guo, Weimeng; Wu, Tianli; Wang, Xiaodeng; Zhang, Dingke; Wang, Shuxia; Chen, Shijian

    2017-10-01

    Herein, porous WP2 nanosheet arrays integrated on graphite paper (P-WP2 NSs/GP) as 3D flexible cathode for electrocatalytic hydrogen evolution reaction (HER) are prepared by in situ phosphidation via vacuum encapsulation assisted by pulsed laser deposition technique. Compared to the electrode without pre-deposition process, the enhanced catalytic activities are attributed to the increased effective catalyst loading and the reinforced charge transport kinetics. The results make the present P-WP2 NSs/GP as a promising cathode for energy conversion and paves a new way for designing and fabricating efficient electrodes toward HER.

  9. Dynamic Modeling of Hydrogen Sulfide within Enclosed Environments in Biosolids Recovery Facilities.

    Science.gov (United States)

    Matos, Rita Ventura; Matias, Natércia; Ferreira, Filipa; Matos, José Saldanha

    2016-12-01

    Hydrogen sulfide emissions from wastewater affect human health and equipment durability, thus presenting a complex issue for utilities. Several VOC emission models have been used before to predict H2S in collection systems and water resources recovery operations, even if with restrictions. By contrast, fewer studies focus on biosolids emissions and modelling. This paper presents a dynamic modelling approach to predict H2S concentration in a tank headspace of a wastewater biosolids recovery facility. Data from one of the largest Portuguese water resources recovery facilities was collected under different facility operating modes. The developed model adequately predicted H2S concentration, with R2 values of 0.89 and 0.78, for different periods of the year, thus showing how modelling may reliably contribute to utility operation decisions.

  10. Ultrasound-assisted Cinnamaldehyde Hydrogenation to Cinnamyl Alcohol at Atmospheric Pressure over Ru-B Amorphous Catalyst

    Institute of Scientific and Technical Information of China (English)

    LI Hui; MA Chun-Jing; LI He-Xing

    2006-01-01

    The ultrafine Ru-B amorphous alloy catalyst was prepared by chemical reduction with KBH4. During liquid phase hydrogenation of cinnamaldehyde at atmospheric pressure, the Ru-B catalyst prepared exhibited excellent selectivity to cinnamyl alcohol. When the hydrogenation was performed with ultrasonic irradiation, the reaction rate could be greatly enhanced while the selectivity to cinnamyl alcohol remained almost unchanged. The hydrogenation rate was increased with the increase of either the ultrasonic frequency or the irradiation time. According to various characterizations, such as XRD, XPS, TEM, BET and ICP, the effect of ultrasonic irradiation on the structural and electronic characteristics of Ru-B catalyst was studied briefly. Meanwhile, the promotion effect of ultrasonication on the catalytic performance was also discussed based on the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol.

  11. The global influence of the hydrogen isotope composition of water on that of bacteriogenic methane from shallow freshwater environments

    Energy Technology Data Exchange (ETDEWEB)

    Waldron, S.; Fallick, A.E. [Scottish Universities Research and Reactor Centre, East Kilbride (United Kingdom); Lansdown, J.M. [Univ. of Washington, Seattle, WA (United States). School of Oceanography; Scott, E.M.; Hall, A.J. [Univ. of Glasgow (United Kingdom)

    1999-08-01

    The authors propose that the hydrogen isotope composition of recently produced microbial methane, {delta}D(CH{sub 4}), in sulfate-poor, shallow freshwater environments, is directly related to the hydrogen isotopic composition of the system water {delta}D(H{sub 2}O). As {delta}D(H{sub 2}O) varies globally, systematic differences in {delta}D(CH{sub 4}) as a function of {delta}D(H{sub 2}O) should be observed. From available mean paired measurements from 46 sites, the relationship for {delta}D(CH{sub 4}) and {delta}D(H{sub 2}O) in the natural environment can be defined as {delta}D(CH{sub 4}) = 0.675{delta}D(H{sub 2}O) {minus}284{per_thousand} (p < 0.0001). This relationship is statistically distinct from that generated by considering three separate laboratory-based anaerobic inoculations that contain similar methanogenic communities to the natural freshwater samples and therefore, are likely to produce methane by similar metabolic pathways: {delta}D(CH{sub 4}) = 0.444{delta}D(H{sub 2}O) {minus}321{per_thousand} (p < 0.0001). The authors suggest that the relationship arising from the laboratory incubations defines the {delta}D(CH{sub 4}) of methane produced at source in shallow freshwater environments. They can approximate that 50% of the variation in natural {delta}D(CH{sub 4}) samples can be explained by {delta}D(H{sub 2}O), with isotopic fractionation postproduction, or mixing with gas already fractionated likely responsible for most of the noise in the natural system and difference of the natural sample relationship to the laboratory relationship. Methanogenic pathway may also influence {delta}D(CH{sub 4}), but the foundations for this hypothesis need to be reconsidered, and field and laboratory data exist that do not support it. The relationships presented here describe {delta}D of methane from only shallow (subsurface) freshwater environments; paired {delta}D(CH{sub 4})-{delta}D(H{sub 2}O) values from other environments (e.g., marine, glacial drift) suggest that a

  12. Persistent Hydrogen Production by the Photo-Assisted Microbial Electrolysis Cell Using a p-Type Polyaniline Nanofiber Cathode.

    Science.gov (United States)

    Jeon, Yongwon; Kim, Sunghyun

    2016-12-08

    A microbial electrolysis cell, though considered as a promising, environmentally friendly technology for hydrogen production, suffers from concomitant production of methane. The high hydrogen/methane ratio at the initial operation stage decreases with time. Here we report for the first time the photoassisted microbial electrolysis cell (MEC) for persistent hydrogen production using polyaniline nanofibers as a cathode. Under 0.8 V external bias and laboratory fluorescent light illumination in a single-chamber MEC, continuous hydrogen production from acetate at a rate of 1.78 mH2 (3)  m(-3)  d(-1) with 79.2 % overall hydrogen recovery was achieved with negligible methane formation for six months. Energy efficiencies based on input electricity as well as input electricity plus substrate were 182 and 66.2 %, respectively. This was attributed to the p-type-semiconductor characteristics of polyaniline nanofibers in which photoexcited electrons are used to reduce protons at the surface and holes are reduced with electrons originating from acetate oxidation at the anode. This method can be extended to microbial wastewater treatment for hydrogen production. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. FEASIBILITY STUDY OF USING COMPLEX OF HYDROGEN PEROXIDE AND SILVER FOR DISINFECTING SWIMMING POOL WATER AND ITS ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    R. Nabizadeh ، N. Samadi ، Z. Sadeghpour ، M. Beikzadeh

    2008-10-01

    Full Text Available In this research the application of Nanosil containing hydrogen peroxide and silver was studied in disinfecting swimming pool water and it's Environment. The effect of the disinfectant on Candida albicans (ATCC No. 10231, Aspergillus niger (ATCCNo. 16404, Pseudomonas aeruginosa (ATCC No. 9027, Serratia marcescens (PTCC No. 1111, Klebsiella pneumoniae (ATCC No. 10031 and Staphylococcus aureus (ATCC No. 29737 was evaluated. The main objective of this experiment was to determine the effective dose of Nanosil which could be used for disinfecting the environment of swimming pools and other surface area. Then, the effectiveness of Nanosil was studied in two private and one public swimming pools. Heterotrophic plate count, thermotolerant coliforms, Pseudomonas aeruginosa and Staphylococcus aureus were monitored as the target microorganisms in disinfection practice According to the result of this study, it is recommended to apply the Nanosil with the concentration of ≥3% (30000 mg/L for contact time of 30 min or more for practical disinfection in swimming pools environment. The application of Nanosil in real conditions of two private and one public swimming pools indicated that the acceptable microbial quality is also achievable if the disinfectant residual concentration would be as high as 20 mg/L in swimming pool water.

  14. Performance of high speed ball bearings with lead plated retainers in liquid hydrogen for potential use in a radiation environment

    Science.gov (United States)

    Wisander, D. W.; Brewe, D. E.; Scibbe, H. W.

    1972-01-01

    Ball bearings (40-mm bore) with lead coated, aluminum-bronze retainers were operated successfully in liquid hydrogen at 30,000 rpm under a thrust load of 1780 newtons (400 lb) for running times up to 15 hours. The lead transfer films on the bearing surfaces prevented galling of bearing components. The lead coated retainers used in this investigation show promise for use in the high radiation environments, where polytetrafluoroethylene (PTFE) based materials are not suitable. Failure was a result of the loss of lead lubricant on the retainer-inner-land and ball-pocket surfaces. The longest bearing life (15 hr) was achieved with a lead coating thickness of 50 micrometers (0.002 in.) on the retainer. Other bearings had lives of 2 to 6 hours.

  15. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

    Hydrogen embrittlement (HE) is a process resulting in a decrease in the fracture toughness or ductility of a metal due to the presence of atomic hydrogen. In addition to pure hydrogen gas as a direct source for the absorption of atomic hydrogen, the damaging effect can manifest itself from other hydrogen-containing gas species such as hydrogen sulfide (H2S), hydrogen chloride (HCl), and hydrogen bromide (HBr) environments. It has been known that H2S environment may result in a much more severe condition of embrittlement than pure hydrogen gas (H2) for certain types of alloys at similar conditions of stress and gas pressure. The reduction of fracture loads can occur at levels well below the yield strength of the material. Hydrogen embrittlement is usually manifest in terms of singular sharp cracks, in contrast to the extensive branching observed for stress corrosion cracking. The initial crack openings and the local deformation associated with crack propagation may be so small that they are difficult to detect except in special nondestructive examinations. Cracks due to HE can grow rapidly with little macroscopic evidence of mechanical deformation in materials that are normally quite ductile. This Technical Memorandum presents a comprehensive review of experimental data for the effects of gaseous Hydrogen Environment Embrittlement (HEE) for several types of metallic materials. Common material screening methods are used to rate the hydrogen degradation of mechanical properties that occur while the material is under an applied stress and exposed to gaseous hydrogen as compared to air or helium, under slow strain rates (SSR) testing. Due to the simplicity and accelerated nature of these tests, the results expressed in terms of HEE index are not intended to necessarily represent true hydrogen service environment for long-term exposure, but rather to provide a practical approach for material screening, which is a useful concept to qualitatively evaluate the severity of

  16. Self-pressurization of a spherical liquid hydrogen storage tank in a microgravity environment

    Science.gov (United States)

    Lin, C. S.; Hasan, M. M.

    1992-01-01

    Thermal stratification and self-pressurization of partially filled liquid hydrogen (LH2) storage tanks under microgravity condition is studied theoretically. A spherical tank is subjected to a uniform and constant wall heat flux. It is assumed that a vapor bubble is located in the tank center such that the liquid-vapor interface and tank wall form two concentric spheres. This vapor bubble represents an idealized configuration of a wetting fluid in microgravity conditions. Dimensionless mass and energy conservation equations for both vapor and liquid regions are numerically solved. Coordinate transformation is used to capture the interface location which changes due to liquid thermal expansion, vapor compression, and mass transfer at liquid-vapor interface. The effects of tank size, liquid fill level, and wall heat flux on the pressure rise and thermal stratification are studied. Liquid thermal expansion tends to cause vapor condensation and wall heat flux tends to cause liquid evaporation at the interface. The combined effects determine the direction of mass transfer at the interface. Liquid superheat increases with increasing wall heat flux and liquid fill level and approaches an asymptotic value.

  17. Hydrogen Isotope Composition of Magmatic Water: Review of Variations due to Source, Igneous Environment, and Degassing Processes

    Science.gov (United States)

    Taylor, B. E.

    2001-05-01

    , isotopic fractionation during diagenesis and metamorphism. Hydrogen isotope fractionation during open-system degassing in the volcanic environment can result in marked depletion of deuterium in both the residual melt (e.g., δ D = -135 ‰ ; based on numerous studies) and the water instantaneously lost from the fractionated melts. Closed-system degassing, e.g. during crystallization of plutonic magma, causes a smaller shift to lower values of δ D as degassing progresses. However, in contrast to variations in δ D in degassed magma, and except at or very near the surface, magmatic water accumulated in wall rocks and/or hydrothermal systems tends to have a restricted range of δ D, with the average value close to that of the undegassed source magma. The apparent range of δ D values expressed by the "magmatic water box" does not necessarily apply to the tracing of magmatic water. Misinterpretation of the "magmatic water box" in regards to quantitative volatile evolution can overlook the importance of isotope mass balance. Several examples of hydrothermal fluids and associated, isotopically depleted magmas will illustrate this point.

  18. Improved efficiency of a large-area Cu(In,Ga)Se₂ solar cell by a nontoxic hydrogen-assisted solid Se vapor selenization process.

    Science.gov (United States)

    Wu, Tsung-Ta; Hu, Fan; Huang, Jyun-Hong; Chang, Chia-ho; Lai, Chih-chung; Yen, Yu-Ting; Huang, Hou-Ying; Hong, Hwen-Fen; Wang, Zhiming M; Shen, Chang-Hong; Shieh, Jia-Min; Chueh, Yu-Lun

    2014-04-01

    A nontoxic hydrogen-assisted solid Se vapor selenization process (HASVS) technique to achieve a large-area (40 × 30 cm(2)) Cu(In,Ga)Se2 (CIGS) solar panel with enhanced efficiencies from 7.1 to 10.8% (12.0% for active area) was demonstrated. The remarkable improvement of efficiency and fill factor comes from improved open circuit voltage (Voc) and reduced dark current due to (1) decreased interface recombination raised from the formation of a widened buried homojunction with n-type Cd(Cu) participation and (2) enhanced separation of electron and hole carriers resulting from the accumulation of Na atoms on the surface of the CIGS film. The effects of microstructural, compositional, and electrical characteristics with hydrogen-assisted Se vapor selenization, including interdiffusion of atoms and formation of buried homojunction, were examined in detail. This methodology can be also applied to CIS (CuInSe2) thin film solar cells with enhanced efficiencies from 5.3% to 8.5% (9.4% for active area) and provides a facile approach to improve quality of CIGS and stimulate the nontoxic progress in the large scale CIGS PV industry.

  19. Implementing Glossing in Mobile-Assisted Language Learning Environments: Directions and Outlook

    Science.gov (United States)

    Lee, Hansol; Lee, Jang Ho

    2013-01-01

    While mobile technology, such as the touch-based smart-phone, has become part of our daily lives, research into and classroom practices surrounding mobile-assisted language learning (MALL) have generally not kept up with the pace of technological development. This situation may be caused in part by the fact that a considerable proportion of…

  20. Perceptions and Reflections on the Role of the Teaching Assistant in the Classroom Environment

    Science.gov (United States)

    Tucker, Stanley

    2009-01-01

    This literature-based article examines a range of factors directly influencing and shaping perceptions of the role of the teaching assistant within UK classrooms. Drawing directly on research gathered and analysed through three systematic literature reviews into "pupils" support and academic engagement' and other contemporary literature,…

  1. Animal-Assisted Literacy: A Supportive Environment for Constrained and Unconstrained Learning

    Science.gov (United States)

    Friesen, Lori; Delisle, Esther

    2012-01-01

    Over the last 20 years or so, the popularity of animal-assisted literacy learning programs has gained momentum in schools and libraries around the world (Intermountain Therapy Animals, 2011). To date, such programs are currently running in four Canadian provinces and 43 U.S. states, as well as in Australia, the United Kingdom, Italy, and India…

  2. Perceptions and Reflections on the Role of the Teaching Assistant in the Classroom Environment

    Science.gov (United States)

    Tucker, Stanley

    2009-01-01

    This literature-based article examines a range of factors directly influencing and shaping perceptions of the role of the teaching assistant within UK classrooms. Drawing directly on research gathered and analysed through three systematic literature reviews into "pupils" support and academic engagement' and other contemporary literature,…

  3. The role of Hydrogen and Creep in Intergranular Stress Corrosion Cracking of Alloy 600 and Alloy 690 in PWR Primary Water Environments ? a Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Hua, F H

    2004-07-12

    Intergranular attack (IGA) and intergranular stress corrosion cracking (IGSCC) of Alloy 600 in PWR steam generator environment has been extensively studied for over 30 years without rendering a clear understanding of the essential mechanisms. The lack of understanding of the IGSCC mechanism is due to a complex interaction of numerous variables such as microstructure, thermomechanical processing, strain rate, water chemistry and electrochemical potential. Hydrogen plays an important role in all these variables. The complexity, however, significantly hinders a clearer and more fundamental understanding of the mechanism of hydrogen in enhancing intergranular cracking via whatever mechanism. In this work, an attempt is made to review the role of hydrogen based on the current understanding of grain boundary structure and chemistry and intergranular fracture of nickel alloys, effect of hydrogen on electrochemical behavior of Alloy 600 and Alloy 690 (e.g. the passive film stability, polarization behavior and open-circuit potential) and effect of hydrogen on PWSCC behavior of Alloy 600 and Alloy 690. Mechanistic studies on the PWSCC are briefly reviewed. It is concluded that further studies on the role of hydrogen on intergranular cracking in both inert and primary side environments are needed. These studies should focus on the correlation of the results obtained at different laboratories by different methods on materials with different metallurgical and chemical parameters.

  4. Analysis of Reference Design for Nuclear-Assisted Hydrogen Production at 750°C Reactor Outlet Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. McKellar; Edwin A. Harvego

    2010-05-01

    The use of High Temperature Electrolysis (HTE) for the efficient production of hydrogen without the greenhouse gas emissions associated with conventional fossil-fuel hydrogen production techniques has been under investigation at the Idaho National Engineering Laboratory (INL) for the last several years. The activities at the INL have included the development, testing and analysis of large numbers of solid oxide electrolysis cells, and the analyses of potential plant designs for large scale production of hydrogen using a high-temperature gas-cooled reactor (HTGR) to provide the process heat and electricity to drive the electrolysis process. The results of this research led to the selection in 2009 of HTE as the preferred concept in the U.S. Department of Energy (DOE) hydrogen technology down-selection process. However, the down-selection process, along with continued technical assessments at the INL, has resulted in a number of proposed modifications and refinements to improve the original INL reference HTE design. These modifications include changes in plant configuration, operating conditions and individual component designs. This report describes the resulting new INL reference design coupled to two alternative HTGR power conversion systems, a Steam Rankine Cycle and a Combined Cycle (a Helium Brayton Cycle with a Steam Rankine Bottoming Cycle). Results of system analyses performed to optimize the design and to determine required plant performance and operating conditions when coupled to the two different power cycles are also presented. A 600 MWt high temperature gas reactor coupled with a Rankine steam power cycle at a thermal efficiency of 44.4% can produce 1.85 kg/s of hydrogen and 14.6 kg/s of oxygen. The same capacity reactor coupled with a combined cycle at a thermal efficiency of 42.5% can produce 1.78 kg/s of hydrogen and 14.0 kg/s of oxygen.

  5. Hydrogen generation by metal corrosion in simulated Waste Isolation Pilot Plant environments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Telander, M.R.; Westerman, R.E. [Battelle Pacific Northwest Lab., Richland, WA (United States)

    1997-03-01

    The corrosion and gas-generation characteristics of four material types: low-carbon steel (the current waste packaging material for the Waste Isolation Pilot Plant), Cu-base and Ti-base (alternative packaging) materials, and Al-base (simulated waste) materials were determined in both the liquid and vapor phase of Brine A, a brine representative of an intergranular Salado Formation brine. Test environments consisted primarily of anoxic brine with overpressures of N{sub 2}, CO{sub 2}, H{sub 2}S, and H{sub 2}. Limited tests of low-carbon steel were also performed in simulated-backfill environments and in brine environments with pH values ranging from 3 to 11. Low-carbon steel reacted at a slow, measurable rate with anoxic brine, liberating H{sub 2} on an equimolar basis with Fe reacted. Presence of CO{sub 2} caused the initial reaction to proceed more rapidly, but CO{sub 2}-induced passivation stopped the reaction if the CO{sub 2} were present in sufficient quantities. Addition of H{sub 2}S to a CO{sub 2}-passivated system caused reversal of the passivation. Low-carbon steel immersed in brine with H{sub 2}S showed no reaction, apparently because of passivation of the steel by formation of FeS. Addition of CO{sub 2} to an H{sub 2}S-passivated system did not reverse the passivation. Cu- and Ti-base materials showed essentially no corrosion when exposed to brine and overpressures of N{sub 2}, CO{sub 2}, and H{sub 2}S except for the rapid and complete reaction between Cu-base materials and H{sub 2}S. The Al-base materials reacted at approximately the same rate as low-carbon steel when immersed in anoxic Brine A; considerably more rapidly in the presence of CO{sub 2} or H{sub 2}S; and much more rapidly when iron was present in the system as a brine contaminant. High-purity Al was much more susceptible to corrosion than the 6061 alloy. No significant reaction took place on any material in any environment in the vapor-phase exposures.

  6. Electrochemical Mitigation of hydrogen Environment Embrittlement of Ultra-High Strength AerMet(Trademark) 100

    Science.gov (United States)

    2006-01-01

    Environments A single edge notch specimen of UNS K92580 was machined, 10.2mm wide x 2.54mm thick. The notch was electrospark -machined to 0.065mm wide...low values in Fig. 17. Unfortunately, its use is limited to overpotentials above r1 = -0.5V, below which Zn deposits from solution. Again, the...white film is noticed on the specimen surface indicating the deposition of Ce(OH) 3 due to the shift in local pH at the sample/electrolyte interface

  7. Tribology in Gaseous Hydrogen

    Science.gov (United States)

    Sawae, Yoshinori; Sugimura, Joich

    Hydrogen is expected as a clean and renewable energy carrier for future environment-friendly society. Many machine elements in hydrogen energy systems should be operating within hydrogen gas and tribological behavior, such as friction and wear, of bearings and seals are affected by the hydrogen environment through some interactions between material surfaces and gaseous hydrogen, i.e., physisorption of hydrogen molecules and following chemisorptions of dissociated atoms on metal surfaces, formation of metal hydride and reduction of metal oxide layer by hydrogen atoms diffused into bulk. Therefore, friction and wear characteristics of tribomaterials in the hydrogen environment should be appropriately understood to establish a design guideline for reliable hydrogen utilizing systems. This paper reviews the current knowledge about the effect of hydrogen on friction and wear of materials, and then describes our recent progress of hydrogen research in the tribology field.

  8. High temperature oxidation of fuel cladding candidate materials in steam-hydrogen environments

    Science.gov (United States)

    Pint, B. A.; Terrani, K. A.; Brady, M. P.; Cheng, T.; Keiser, J. R.

    2013-09-01

    Alternative fuel cladding materials to Zr alloys are being investigated for enhanced accident tolerance, which specifically involves oxidation resistance to steam or steam-H2 environments at ⩾1200 °C for short times. Based on a comparison of a range of commercial and model alloys, conventional austenitic steels do not have sufficient oxidation resistance with only ˜18Cr-10Ni. Higher alloyed type 310 stainless steel is protective but Ni is not a desirable alloy addition for this application. Results at 1350 °C indicated that FeCrAl alloys and CVD SiC remain oxidation resistant in steam. At 1200 °C, high (⩾25% Cr) ferritic alloys appear to be good candidates for this application. Higher pressures (up to 20.7 bar) and H2 additions appeared to have a limited effect on the oxidation behavior of the most oxidation resistant alloys, but higher pressures accelerated the maximum metal loss for less oxidation resistant steels and less metal loss was observed for type 317 L tubing in a H2-50%H2O environment at 10.3 bar compared to 100% H2O.

  9. Causes and Countermeasures of Hydrogen Knobbing for the Head of Circumfluence Tank in Wet Hydrogen Sulfide Environment%湿硫化氢环境回流罐封头氢鼓包原因分析

    Institute of Scientific and Technical Information of China (English)

    张转连

    2011-01-01

    The cause and influence factors of hydrogen knobbing for inner surface of the head of circumfluence tank were analyzed in the refinery.Appropriate preventive measures have been proposed to prevent a similar situation in wet hydrogen sulfide environment.%通过对某炼油厂生产装置中回流罐进气端封头内表面产生氢鼓包的原因及影响因素的分析,提出了在湿硫化氢环境下防止回流罐产生类似情况的预防措施.

  10. Hydrogen production performance of membrane-less bio-electrochemically assisted microbial reactor%无膜生物电化学制氢反应器的产气特性

    Institute of Scientific and Technical Information of China (English)

    李金来; 李伟; 王丽梅; 贾永强; 万新华; 冯亚青

    2011-01-01

    Hydrogen production performance of a membrane-less bio-electrochemically assisted microbial reactor was studied in this paper. Membrane-less microbial reactor consisted of carbon felt as anode, carbon plate supported by self-made Ni-Al-Sn alloy powders (Ni-50% ,Al-45% ,Sn-5% ) as cathode and acetate as electrolyte for generating hydrogen. Its principle was that the organic was degraded by microbe to produce electron and protons in the anode chamber, and then protons arriving at cathode got electron and generated hydrogen through an applied voltage between two electrodes of membrane-less microbial reactor. The influences of carbon felt amount used for the anode, environment temperature, and applied voltage, etc. on hydrogen production rate and hydrogen selectivity were studied. And the optimal results demonstrated that the rate of hydrogen production reached at 4.21 m3/(d·m3) and the highest hydrogen selectivity was 70.4% when the anode surface area was 900 cm2, the environment temperature was 30 ℃ and the applied voltage was 0. 9 V.%研究了无膜生物电化学制氢反应器的设计及产气特性。设计和组装的电化学制氢反应器为无膜电化学制氢反应器。它是以碳毡作为阳极,以负载一定量Ni-A1-Sn(Ni-50%、Al-45%、Sn-5%)合金粉催化剂的石墨板作为阴极,乙酸钠作为电解质。其工作原理是在两极间外加一定电压,阳极区的微生物降解有机物产生电子到达阴极,质子在阴极得到电子生成氢气。主要考察了阳极碳毡数量、环境温度、外加电压等因素对产气速率和氢气选择性的影响。结果表明,当阳极面积为900 cm2、环境温度为30℃、外加电压为0.9 V时,反应器产气速率最高可达4.21 m3/(d·m3),氢气选择性最高为70.4%。

  11. Interview with Susan Morrisey Livingstone, Assistant Secretary of the Army for Installations, Logistics and Environment

    Science.gov (United States)

    2007-03-01

    US Army Corps of Engineers, Engineer Research and Development Center - The Army Environmental History Project Interview with Susan Morrisey...The Army Environmental History Project ERDC/CERL M-07-1 March 2007 Interview with Susan Morrisey Livingstone, Assistant Secretary of the Army for...Environmental Quality," Work Item 6HF9K5, "The Army Environmental History Project." The technical monitor was John J. Fittipaldi, Army Environmental

  12. An HL7-FHIR-based Object Model for a Home-Centered Data Warehouse for Ambient Assisted Living Environments.

    Science.gov (United States)

    Schwartze, Jonas; Jansen, Lars; Schrom, Harald; Wolf, Klaus-Hendrik; Haux, Reinhold; Marschollek, Michael

    2015-01-01

    Current AAL environments focus on assisting a single person with seperated technologies. There is no interoperability between sub-domains in home environments, like building energy management or housing industry services. BASIS (Building Automation by a Scalable and Intelligent System) aims to integrate all sensors and actuators into a single, efficient home bus. First step is to create a semtically enriched data warehouse object model. We choose FHIR and built an object model mainly based on the Observation, Device and Location resources with minor extensions needed by AAL-foreign sub domains. FHIR turned out to be very flexible and complete for other home related sub-domains. The object model is implemented in a separated software-partition storing all structural and procedural data of BASIS.

  13. Controlling the quantum-memory-assisted entropic uncertainty relation by quantum-jump-based feedback control in dissipative environments

    Science.gov (United States)

    Yu, Min; Fang, Mao-Fa

    2017-09-01

    The dynamic properties of the quantum-memory-assisted entropic uncertainty relation for a system comprised of a qubit to be measured and a memory qubit are investigated. We explore the behaviors of the entropic uncertainty and its lower bound in three different cases: Only one of the two qubits interacts with an external environment and subjects to quantum-jump-based feedback control, or both of the two qubits independently experience their own environments and local quantum-jump-based feedback control. Our results reveal that the quantum-jump-based feedback control with an appropriate feedback parameter can reduce the entropic uncertainty and its lower bound, and for the three different scenarios, the reduction in the uncertainty relates to different physical quantities. Besides, we find out that the quantum-jump-based feedback control not only can remarkably decrease the entropic uncertainty, but also can make the uncertainty reach its lower bound where the dynamical map becomes unital.

  14. Virtual environment: assistance in nursing care for the deaf based on the protocol of primary care

    National Research Council Canada - National Science Library

    Rodrigues, Silvia Cristina Martini; Damião, Gardênia Costa

    2014-01-01

    Presenting a Virtual Environment (VE) based on the Protocol of Treatment of Hypertension and Diabetes Mellitus type 2, used in Primary Care for evaluation of dietary habits in nursing consultations...

  15. Virtual Environment: assistance in nursing care for the deaf based on the protocol of Primary Care

    National Research Council Canada - National Science Library

    Rodrigues, Silvia Cristina Martini; Damião, Gardênia Costa

    2014-01-01

    Objective: Presenting a Virtual Environment (VE) based on the Protocol of Treatment of Hypertension and Diabetes Mellitus type 2, used in Primary Care for evaluation of dietary habits in nursing consultations. Method...

  16. Fast environment-friendly ball mill-assisted deep eutectic solvent-based extraction of natural products.

    Science.gov (United States)

    Wang, Man; Wang, Jiaqin; Zhang, Yue; Xia, Qian; Bi, Wentao; Yang, Xiaodi; Chen, David Da Yong

    2016-04-22

    A fast environment-friendly extraction method, ball mill-assisted deep eutectic solvent-based extraction, was used for the extraction of natural products from plants. In this study, tanshinones were selected as target compounds to evaluate the efficiency of the developed extraction method. Under the optimized experimental conditions, cryptotanshinone (0.176 mg/g), tanshinone I (0.181 mg/g), and tanshinone II A (0.421 mg/g) were extracted from Salvia miltiorrhiza Bunge, and the developed method was found to be greener, more efficient, and faster than conventional, environmentally harmful extraction methods such as methanol-based ultrasound-assisted extraction and heat reflux extraction. The analytical performances including recovery, reproducibility (RSD, n=5), correlation of determination (r(2)), and the limit of detection, with the ranges of 96.1-103.9%, 1.6-1.9%, 0.9973-0.9984, and 5-8 ng/mL, were respectively obtained. Application of ball mill-assisted deep eutectic solvent-based extraction may fundamentally shape the future development of extraction methods.

  17. Ambient and smartphone sensor assisted ADL recognition in multi-inhabitant smart environments

    OpenAIRE

    Roy, Nirmalya; Misra, Archan; Cook, Diane

    2015-01-01

    Activity recognition in smart environments is an evolving research problem due to the advancement and proliferation of sensing, monitoring and actuation technologies to make it possible for large scale and real deployment. While activities in smart home are interleaved, complex and volatile; the number of inhabitants in the environment is also dynamic. A key challenge in designing robust smart home activity recognition approaches is to exploit the users' spatiotemporal behavior and location, ...

  18. Status of activities on the inactive uranium mill tailings sites remedial action program. Office of the Assistant Secretary for Environment

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    This report on the status of the Office of Environment's program for inactive uranium mill tailings sites is an analysis of the current status and a forecast of future activities of the Office of Environment. The termination date for receipt of information was September 30, 1980. Aerial radiological surveys and detailed ground radiological assessments of properties within the communities in the vicinity of the designated processing sites in Canonsburg, Pennsylvania, Salt Lake City, Utah, and Boise, Idaho led to the designation of an initial group of vicinity properties for remedial action. The potential health effects of the residual radioactive materials on or near these properties were estimated, and the Assistant Secretary for Environment recommended priorities for performing remedial action to the Department's Assistant Secretary for Nuclear Energy. In designating these properties and establishing recommended priorities for performing remedial action, the Office of Environment consulted with the Environmental Protection Agency, the Nuclear Regulatory Commission, representatives from the affected State and local governments, and individual property owners. After notifying the Governors of each of the affected States and the Navajo Nation of the Secretary of Energy's designation of processing sites within their areas of jurisdiction and establishment of remedial action priorities, a Sample Cooperative Agreement was developed by the Department in consultation with the Nuclear Regulatory Commission and provided to the affected States and the Navajo Nation for comments. During September 1980, a Cooperative Agreement with the Commonwealth of Pennsylvania for the designated Canonsburg processing site was executed by the Department. It is anticipated that a Cooperative Agreement between the State of Utah and the Department to perform remedial actions at the designated Salt Lake City site will be executed in the near future.

  19. Effect of Simulated High Hydrogen Content Combustion Environments on Abradable Properties of Ceramic Turbine Coatings

    Science.gov (United States)

    Basu Majumder, Madhura

    Air plasma sprayed (APS) abradable coatings are used in the turbine hot section to reduce the stator-rotor gap, minimizing gas leakage. These coatings are designed to exhibit controlled removal of material in thin layers when the turbine blades sweep through the coating, which protects the mechanical integrity of the turbine blade. In an effort to lower CO2 emissions, high H2 content fuel is being explored. This change in chemical composition of the fuel may affect the microstructure, abradability and durability of the coatings at turbine operational temperatures. The presence of high water vapor in the combustion chamber leads to accelerated degradation of the sacrificial coating materials. In this work, zirconia based composite materials with a machinable phase and varied porosity have been used to study microstructural evolution, thermal and chemical stability of the phases and abradable characteristics of baseline coating systems in both humid and dry environments. Investigation of the mechanisms that control the removal of materials and performance of abradable coatings through thermo-mechanical tests will be discussed.

  20. Evaluation of hydrogen trapping mechanisms during performance of different hydrogen fugacity in a lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Silverstein, R., E-mail: barrav@post.bgu.ac.il [Department of Material Science and Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Eliezer, D. [Department of Material Science and Engineering, Ben-Gurion University of the Negev, Beer-Sheva (Israel); Glam, B.; Eliezer, S.; Moreno, D. [Soreq Nuclear Research Center, Yavne, 81800 (Israel)

    2015-11-05

    Hydrogen trapping behavior in a lean duplex stainless steel (LDS) is studied by means of thermal desorption spectrometry (TDS). The susceptibility of a metal to hydrogen embrittlement is directly related to the trap characteristics: source or sink (reversible or irreversible, respectively). Since trapping affects the metal's diffusivity, it has a major influence on the hydrogen assisted cracking (HAC) phenomenon. It is known from previously published works that the susceptibility will depend on the competition between reversible and irreversible traps; meaning a direct relation to the hydrogen's initial state in the steel. In this research the trapping mechanism of LDS, exposed to different hydrogen charging environments, is analyzed by means of TDS. The TDS analysis was supported and confirmed by means of X-ray diffraction (XRD), hydrogen quantitative measurements and microstructural observations. It was found that gaseous charging (which produces lower hydrogen fugacity) creates ∼22% higher activation energy for hydrogen trapping compared with cathodic charging (which produces higher hydrogen fugacity). These results are due to the different effects on the hydrogen behavior in LDS which causes a major difference in the hydrogen contents and different hydrogen assisted phase transitions. The highest activation energy value in the cathodic charged sample was ascribed to the dominant phase transformation of γ → γ{sup ∗}, whereas in the gaseous charged sample it was ascribed to the dominant formation of intermetallic compound, sigma (σ). The relation between hydrogen distribution in LDS and hydrogen trapping mechanism is discussed in details. - Highlights: • The relation between hydrogen distribution and trapping in LDS is discussed. • Hydrogen's initial state in LDS causes different microstructural changes. • Gaseous charged LDS creates higher trapping energy compared to cathodic charged LDS. • The dominant phase transformation in

  1. Hydrogen and electricity production in a light-assisted microbial photoelectrochemical cell with CaFe2O4 photocathode

    Science.gov (United States)

    Chen, Qing-Yun; Zhang, Kai; Liu, Jian-Shan; Wang, Yun-Hai

    2017-04-01

    A microbial photoelectrochemical cell (MPEC) was designed with a p-type CaFe2O4 semiconductor as the photoelectrode for simultaneous hydrogen and electricity production under light illumination. The CaFe2O4 photoelectrode was synthesized by the sol-gel method and well characterized by x-ray diffraction, field emission scanning electron microscope, and UV-Vis-NIR spectrophotometer. The linear sweep voltammogram of the CaFe2O4 photoelectrode presented the cathodic photocurrent output. For the MPEC, with an external resistance of 2000 Ω, the maximum power density of 143 mW was obtained. Furthermore, with an external resistance of 100 Ω, the maximum hydrogen production rate of 6.7 μL·cm-2 could be achieved. The MPEC with CaFe2O4 photocathode was compared to MPEC with other photocathodes as well as photocatalytic water splitting technology.

  2. Catalytic hydrogen/oxygen reaction assisted the proton exchange membrane fuel cell (PEMFC) startup at subzero temperature

    Science.gov (United States)

    Sun, Shucheng; Yu, Hongmei; Hou, Junbo; Shao, Zhigang; Yi, Baolian; Ming, Pingwen; Hou, Zhongjun

    Fuel cells for automobile application need to operate in a wide temperature range including freezing temperature. However, the rapid startup of a proton exchange membrane fuel cell (PEMFC) at subfreezing temperature, e.g., -20 °C, is very difficult. A cold-start procedure was developed, which made hydrogen and oxygen react to heat the fuel cell considering that the FC flow channel was the characteristic of microchannel reactor. The effect of hydrogen and oxygen reaction on fuel cell performance at ambient temperature was also investigated. The electrochemical characterizations such as I- V plot and cyclic voltammetry (CV) were performed. The heat generated rate for either the single cell or the stack was calculated. The results showed that the heat generated rate was proportional to the gas flow rate when H 2 concentration and the active area were constant. The fuel cell temperature rose rapidly and steadily by controlling gas flow rate.

  3. Time-dependent density functional theory study on the excited-state hydrogen-bonding characteristics of polyaniline in aqueous environment

    Science.gov (United States)

    Zhang, Yahong; Duan, Yuping; Liu, Jin

    2017-01-01

    A theoretical study was carried out to study the excited-state of hydrogen-bonding characteristics of polyaniline (PANI) in aqueous environment. The hydrogen-bonded PANI-H2O complexes were studied using first-principles calculations based on density functional theory (DFT). The electronic excitation energies and the corresponding oscillator strengths of the low-lying electronically excited states for hydrogen-bonded complexes were calculated by time-dependent density functional theory (TDDFT). The ground-state geometric structures were optimized, and it is observed that the intermolecular hydrogen bonds Csbnd N ⋯ Hsbnd O and Nsbnd H ⋯ Osbnd H were formed in PANI-H2O complexes. The formed hydrogen bonds influenced the bond lengths, the charge distribution, as well as the spectral characters of the groups involved. It was concluded that all the hydrogen-bonded PANI-H2O complexes were primarily excited to the S1 states with the largest oscillator strength. In addition, the orbital transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) involved intramolecular charge redistribution resulting to increase the electron density of the quinonoid rings.

  4. Microwave-assisted modulated synthesis of zirconium-based metal–organic framework (Zr-MOF) for hydrogen storage applications

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2014-05-01

    Full Text Available Zirconium-based metal–organic framework (Zr-MOF) was synthesized using a microwave-assisted modulated method in a short reaction time of 5 min. The Zr-MOF material was highly crystalline with well-defined octahedral shaped crystals, and it exhibited...

  5. Co-Designing Ambient Assisted Living (AAL Environments: Unravelling the Situated Context of Informal Dementia Care

    Directory of Open Access Journals (Sweden)

    Amy S. Hwang

    2015-01-01

    Full Text Available Ambient assisted living (AAL aims to help older persons “age-in-place” and manage everyday activities using intelligent and pervasive computing technology. AAL research, however, has yet to explore how AAL might support or collaborate with informal care partners (ICPs, such as relatives and friends, who play important roles in the lives and care of persons with dementia (PwDs. In a multiphase codesign process with six (6 ICPs, we envisioned how AAL could be situated to complement their care. We used our codesigned “caregiver interface” artefacts as triggers to facilitate envisioning of AAL support and unpack the situated, idiosyncratic context within which AAL aims to assist. Our findings suggest that AAL should be designed to support ICPs in fashioning “do-it-yourself” solutions that complement tacitly improvised care strategies and enable them to try, observe, and adapt to solutions over time. In this way, an ICP could decide which activities to entrust to AAL support, when (i.e., scheduled or spontaneous and how a system should provide support (i.e., using personalized prompts based on care experience, and when adaptations to system support are needed (i.e., based alerting patterns and queried reports. Future longitudinal work employing participatory, design-oriented methods with care dyads is encouraged.

  6. Virtual Environment: assistance in nursing care for the deaf based on the protocol of Primary Care

    Directory of Open Access Journals (Sweden)

    Silvia Cristina Martini Rodrigues

    2014-08-01

    Full Text Available Objective: Presenting a Virtual Environment (VE based on the Protocol of Treatment of Hypertension and Diabetes Mellitus type 2, used in Primary Care for evaluation of dietary habits in nursing consultations. Method: An experimental study applied by two nurses and a nurse manager, in a sample of 30 deaf patients aged between 30 and 60 years. The environment was built in Visual Basic NET and offered eight screens about feeding containing food pictures, videos in Libras (Brazilian sign language and audio. The analysis of the VE was done through questionnaires applied to patients and professionals by the Poisson statistical test. Results: The VE shows the possible diagnostics in red, yellow, green and blue colors, depending on the degree of patients’ need. Conclusion: The environment obtained excellent acceptance by patients and nurses, allowing great interaction between them, even without an interpreter. The time in consultation was reduced to 15 minutes, with the preservation of patient privacy.

  7. [Virtual environment: assistance in nursing care for the deaf based on the protocol of primary care].

    Science.gov (United States)

    Rodrigues, Silvia Cristina Martini; Damião, Gardênia Costa

    2014-08-01

    Presenting a Virtual Environment (VE) based on the Protocol of Treatment of Hypertension and Diabetes Mellitus type 2, used in Primary Care for evaluation of dietary habits in nursing consultations. An experimental study applied by two nurses and a nurse manager, in a sample of 30 deaf patients aged between 30 and 60 years. The environment was built in Visual Basic NET and offered eight screens about feeding containing food pictures, videos in Libras (Brazilian sign language) and audio. The analysis of the VE was done through questionnaires applied to patients and professionals by the Poisson statistical test. The VE shows the possible diagnostics in red, yellow, green and blue colors, depending on the degree of patients' need. The environment obtained excellent acceptance by patients and nurses, allowing great interaction between them, even without an interpreter. The time in consultation was reduced to 15 minutes, with the preservation of patient privacy.

  8. Preparation of high-quality hydrogenated amorphous silicon film with a new microwave electron cyclotron resonance chemical vapour deposition system assisted with hot wire

    Institute of Scientific and Technical Information of China (English)

    Zhu Xiu-Hong; Chen Guang-Hua; Yin Sheng-Yi; Rong Yan-Dong; Zhang Wen-Li; Hu Yue-Hui

    2005-01-01

    The preparation of high-quality hydrogenated amorphous silicon (a-Si:H) film with a new microwave electron cyclotron resonance-chemical vapour deposition (MWECR-CVD) system assisted with hot wire is presented. In this system the hot wire plays an important role in perfecting the microstructure as well as improving the stability and the optoelectronic properties of the a-Si:H film. The experimental results indicate that in the microstructure of the a-Si:H film, the concentration of dihydride is decreased and a trace of microcrystalline occurs, which is useful to improve its stability, and that in the optoelectronic properties of the a-Si:H film, the deposition rate reaches above 2.0nm/s and the photosensitivity increases up to 4.71× 105.

  9. Effects of hydrogen water chemistry on corrosion fatigue behavior of cold-worked 304L stainless steel in simulated BWR coolant environments

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, M.F., E-mail: mfchiang@iner.gov.tw [Institute of Nuclear Energy Research, Division of Nuclear Fuels and Materials, Lungtan, Taoyuan 325, Taiwan (China); Young, M.C.; Huang, J.Y. [Institute of Nuclear Energy Research, Division of Nuclear Fuels and Materials, Lungtan, Taoyuan 325, Taiwan (China)

    2011-04-15

    Corrosion fatigue behavior of stainless steel 304L (SS304L) in a simulated BWR coolant with hydrogen injection was investigated. Hydrogen water chemistry slightly mitigated the corrosion fatigue degradation of the as-received SS304L specimens, but, on the contrary, it slightly increased the corrosion fatigue crack growth rates (CFCGRs) of the cold-worked specimens. All the CFCGR-tested specimens showed similar fracture features, except for the amounts of deposited corrosion debris. The results indicated that decreasing the oxygen concentration of water environment is not an effective measure to suppress the fatigue crack growth rate of cold-worked SS304L. The CFCGRs of the SS304L were determined by an interaction between corrosion, oxide-induced crack closure and cold work in corrosive environments. At a specific level of reduction, cold work could enhance the corrosion fatigue resistance of SS304 both in the air-saturated and HWC coolant environments.

  10. Effects of hydrogen water chemistry on corrosion fatigue behavior of cold-worked 304L stainless steel in simulated BWR coolant environments

    Science.gov (United States)

    Chiang, M. F.; Young, M. C.; Huang, J. Y.

    2011-04-01

    Corrosion fatigue behavior of stainless steel 304L (SS304L) in a simulated BWR coolant with hydrogen injection was investigated. Hydrogen water chemistry slightly mitigated the corrosion fatigue degradation of the as-received SS304L specimens, but, on the contrary, it slightly increased the corrosion fatigue crack growth rates (CFCGRs) of the cold-worked specimens. All the CFCGR-tested specimens showed similar fracture features, except for the amounts of deposited corrosion debris. The results indicated that decreasing the oxygen concentration of water environment is not an effective measure to suppress the fatigue crack growth rate of cold-worked SS304L. The CFCGRs of the SS304L were determined by an interaction between corrosion, oxide-induced crack closure and cold work in corrosive environments. At a specific level of reduction, cold work could enhance the corrosion fatigue resistance of SS304 both in the air-saturated and HWC coolant environments.

  11. The operational performance of hydrogen masers in the Deep Space Network (the performance of laboratory reference frequency standards in an operational environment)

    Science.gov (United States)

    Ward, S. C.

    1981-01-01

    Spacecraft navigation to the outer planets (Jupiter and beyond) places very stringent demands upon the performance of frequency and time (F&T) reference standards. The Deep Space Network (DSN) makes use of hydrogen masers as an aid in meeting the routine F&T operational requirements within the 64 m antenna network. Results as of October 1980 indicate the hydrogen masers are performing within the required specifications. Two problem areas are discussed: insufficient control over the environment in which the reference standards reside; and frequency drift.

  12. Semi-autonomous mobility assistance for power wheelchair users navigating crowded environments.

    Science.gov (United States)

    Ashley, Daniel; Ashley, Kyle; Alqasemi, Redwan; Dubey, Rajiv

    2017-07-01

    Power wheelchair users suffering from cognitive or physical impairment often face difficulties in maneuvering their wheelchairs through crowded environments. Currently, users need to be continuously aware of all traffic around them to actively avoid all collisions. This is an especially difficult task since many wheelchair users are unable to accurately view or perceive their surroundings. Additionally, imprecise joystick control, slowed reaction time, or imperfect interpretation of the environment can lead to unintended collisions with objects in the environment. This work looks to augment user's input with data gathered from an ultrasonic sensor ring to prevent accidental collisions. Using data gathered from the sensors, we detect objects within a certain radius of the chair. This sensor information is combined with the user input from a joystick to generate a potential field description for the intended motion of the wheelchair. An optimal motion vector is calculated which works to avoid collision with obstacles. Ultimately, this control method reduces the cognitive load on the user and enables them to navigate complex environments by providing simple and/or imprecise input to the system.

  13. Roles of Intramolecular and Intermolecular Hydrogen Bonding in a Three-Water-Assisted Mechanism of Succinimide Formation from Aspartic Acid Residues

    Directory of Open Access Journals (Sweden)

    Ohgi Takahashi

    2014-08-01

    Full Text Available Aspartic acid (Asp residues in peptides and proteins are prone to isomerization to the β-form and racemization via a five-membered succinimide intermediate. These nonenzymatic reactions have relevance to aging and age-related diseases. In this paper, we report a three water molecule-assisted, six-step mechanism for the formation of succinimide from Asp residues found by density functional theory calculations. The first two steps constitute a stepwise iminolization of the C-terminal amide group. This iminolization involves a quintuple proton transfer along intramolecular and intermolecular hydrogen bonds formed by the C-terminal amide group, the side-chain carboxyl group, and the three water molecules. After a conformational change (which breaks the intramolecular hydrogen bond involving the iminol nitrogen and a reorganization of water molecules, the iminol nitrogen nucleophilically attacks the carboxyl carbon of the Asp side chain to form a five-membered ring. This cyclization is accompanied by a triple proton transfer involving two water molecules, so that a gem-diol tetrahedral intermediate is formed. The last step is dehydration of the gem-diol group catalyzed by one water molecule, and this is the rate-determining step. The calculated overall activation barrier (26.7 kcal mol−1 agrees well with an experimental activation energy.

  14. Quantitative characterization of cleavage and hydrogen-assisted quasi-cleavage fracture surfaces with the use of confocal laser scanning microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Merson, E. [Institute of Advanced Technologies, Togliatti State University, 445667 (Russian Federation); Kudrya, A.V.; Trachenko, V.A. [Department of Physical Metallurgy and the Physics of Strength, NUST MISiS, Moscow 119490 (Russian Federation); Merson, D. [Institute of Advanced Technologies, Togliatti State University, 445667 (Russian Federation); Laboratory for Advanced Materials, Kazan Federal University, Naberezhnye Chelny 423812, Republic of Tatarstan (Russian Federation); Danilov, V. [Institute of Advanced Technologies, Togliatti State University, 445667 (Russian Federation); Vinogradov, A. [Institute of Advanced Technologies, Togliatti State University, 445667 (Russian Federation); Department of Engineering Design and Materials, Norwegian University of Science and Technology – NTNU, N-7491 Trondheim (Norway)

    2016-05-17

    “True” cleavage (TC) and quasi-cleavage (QC) fracture surfaces of low-carbon steel specimens tested in liquid nitrogen and after hydrogen charging respectively were investigated by quantitative confocal laser scanning microscopy (CLSM) and conventional scanning electron microscopy (SEM) with electron-backscattered diffraction (EBSD). Topological and crystallographic features of the TC fracture surface are found in good agreement with the generally accepted cleavage mechanism: TC facets diameters correspond to those of grains; the crack path strictly follows the crystallographic orientation of grains and the most of the cleavage cracks are parallel to {100} planes. On the 2D SEM images, the QC facets appeared resembling the TC ones in terms of river line patterns, shapes and sizes. However, the substantial differences between the topography of these two kinds of fracture surfaces were revealed by 3D CLSM: the average misorientation angle between QC facets and the roughness of the QC fracture surface were much lower than those measured for TC. It is demonstrated that all these features are attributed to the specific fracture mechanism operating during hydrogen-assisted cracking.

  15. The effect of the gas composition on hydrogen-assisted NH3-SCR over Ag/Al2O3

    DEFF Research Database (Denmark)

    Tamm, Stefanie; Fogel, Sebastian; Gabrielsson, Pär;

    2013-01-01

    In addition to high activity in hydrocarbon-SCR, Ag/Al2O3 catalysts show excellent activity for NOx reduction for H2-assisted NH3-SCR already at 200°C. Here, we study the influence of different gas compositions on the activity of a pre-sulfated 6wt% Ag/Al2O3 catalyst for NOx reduction, and oxidat...

  16. Robot Assisted Wireless Sensor Network for Monitoring and Detection of Explosives in Indoor Environment

    Directory of Open Access Journals (Sweden)

    Joshua D Freeman,

    2011-05-01

    Full Text Available In recent years, remote environment monitoring has been significantly improved with wireless sensor networking technology. This paper presents the real time streaming of an indoor environment using a wireless sensor network and a set of self-navigating robots. Mobile robots with mounted sensors will autonomously navigate through an indoor area with unknown obstacles. The robots will be able toavoid obstacles and move around the region. The robots sense the environmental parameters of the region, and send that data to the remote monitoring terminals using an underlying wireless sensornetwork. This design is applicable to networks where some of the sensors may not have sufficient range to sense data more accurately and closer monitoring is required. Effective path planning for the mobile robot is achieved by combining a map of the area, the sensor readings and the radio strength of the sensor network. Email alerts can be sent to officials if the sensed data goes above a predefined threshold level, thus successfully detecting the presence of explosives in a given area. This system streams the data in realtimeto the Internet making it possible for authorized personnel to view the status of the environment online.

  17. Hydrogen isotopic characteristics and their genetic relationships for individual n-alkanes in plants and sediments from Zoigê marsh sedimentary environment

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To understand internal relations of their hydrogen isotopic compositions in typical marsh environment, we, using GC-IRMS analytical technique, measured the hydrogen isotopes of individual n-alkanes in the herbaceous plant, woody plant leaf, and sediments from Zoigê marsh in China. The results show significant differences in the hydrogen isotopic compositions of n-alkanes among the different kinds of plants and the different species in the same kind. δD values of n-alkanes in the herbaceous plants (from -254‰ to -184‰) are lighter than those in woody plant leaf ( from -195‰ to -142‰ ), and the hydrogen isotopic compositions of n-alkanes in K. tibetica P. are lighter than P. pratensis L. The mean δD values of n-alkanes in the sediments from Zoigê marsh reflect that they were derived from herbaceous plants, which is consistent with the peat samples being composed mainly of herbaceous plant remnants. The significant differences in hydrogen isotopic compositions of n-alkanes among the sedimentary samples are caused possibly by environment factors and the difference in input quantity of different herbaceous plants. A certain negative correlation exists between the δ13C and δD values of n-alkanes in the samples, and plant types can be distinguished using the cross plot of δD vs. δ13C values of n-alkanes in the plants. These data and recognitions provide scientific basis for hydrogen isotopic applied research of individual n-alkanes.

  18. Environmentally assisted cracking behavior of dissimilar metal weldments in simulated BWR coolant environments

    Science.gov (United States)

    Huang, J. Y.; Chiang, M. F.; Jeng, S. L.; Huang, J. S.; Kuo, R. C.

    2013-01-01

    The environmentally assisted cracking behavior of dissimilar metal (DM) welds, including Alloy 52-A 508 and Alloy 82-A508, under simulated BWR coolant conditions was studied. Effects of postweld heat treatment and sulfur content of the base metal on the corrosion fatigue and SCC growth rates of DM welds were evaluated. The crack growth rates for the DM weld heat-treated at 621 °C for 24 h were observed to be faster than those for the as-welded. But the DM weld heat-treated at 621 °C for 8 h + 400 °C for 200 h showed better SCC resistance than the as-welded. The longer the heat treatment at 621 °C, the higher the chromium carbides density along the grain boundary was observed. Sulfur could diffuse out of the base metal and segregate along the grain boundaries of the dilution zone, leading to weakening the grain boundary strength and the SCC resistance of the Alloy 52-A508 weld.

  19. FACTORS AFFECTING TEACHING THE CONCEPT of RENEWABLE ENERGY in TECHNOLOGY ASSISTED ENVIRONMENTS AND DESIGNING PROCESSES in THE DISTANCE EDUCATION MODEL

    Directory of Open Access Journals (Sweden)

    A. Seda YUCEL

    2007-01-01

    Full Text Available The energy policies of today focus mainly on sustainable energy systems and renewable energy resources. Chemistry is closely related to energy recycling, energy types, renewable energy, and nature-energy interaction; therefore, it is now an obligation to enrich chemistry classes with renewable energy concepts and related awareness. Before creating renewable energy awareness, the factors thought to affect such awareness should be determined. Knowing these factors would facilitate finding out what to take into account in creating renewable energy awareness. In this study, certain factors thought to affect the development of renewable energy awareness were investigated. The awareness was created through a technology-assisted renewable energy module and assessed using a renewable energy assessment tool. The effects of the students’ self-directed learning readiness with Guglielmino (1977, inner-individual orientation, and anxiety orientation on the awareness were examined. These three factors were found to have significant effects on renewable energy, which was developed through technology utilization. In addition, based on the finding that delivering the subject of renewable energy in technology assisted environments is more effective, the criteria that should be taken into consideration in transforming this subject into a design model that is more suitable for distance education were identified.

  20. Learning English Vocabulary in a Mobile Assisted Language Learning (MALL Environment: A Sociocultural Study of Migrant Women

    Directory of Open Access Journals (Sweden)

    Kham Sila Ahmad

    2015-05-01

    Full Text Available This paper reports on a case study of a group of six non-native English speaking migrant women’s experiences learning English vocabulary in a mobile assisted language learning (MALL environment at a small community centre in Western Australia. A sociocultural approach to learning vocabulary was adopted in designing the MALL lessons that the women undertook. The women provided demographic information, responded to questions in a pre-MALL semi-structured interview, attended the MALL lessons, and completed a post-MALL semi-structured interview. This study explores the sociocultural factors that affect migrant women’s language learning in general, and vocabulary in particular. The women’s responses to MALL lessons and using the tablet reveal a positive effect in their vocabulary learning.

  1. Use of hydrogen peroxide treatment and crystal violet agar plates for selective recovery of bacteriophages from natural environments

    Energy Technology Data Exchange (ETDEWEB)

    Asghari, A.; Farrah, S.R.; Bitton, G. (Univ. of Florida, Gainesville (United States))

    1992-04-01

    Hydrogen peroxide inactivated bacteriophages and bacteria at different rates. A concentration of 0.1% hydrogen peroxide reduced the numbers of several bacteria by an average of 94% but caused an average of 25% inactivation in the numbers of bacteriophages tested. Treating natural samples with hydrogen peroxide selectively reduced the indigenous bacterial flora and permitted better visualization of plaques of lawns of Escherichia coli C-3000. In some cases indigenous gram-positive bacteria were relatively resistant to hydrogen peroxide, but their growth could be limited by incorporation of crystal violet into the bottom agar used for plaque assays. The use of hydrogen peroxide treatment and crystal violet-containing plates permitted recovery of more phages from natural samples than did other procedures, such as chloroform pretreatment or the use of selective plating agar such as EC medium.

  2. Lewis‐Acid‐assisted Hydrogen Atom Transfer to Manganese(V)‐Oxo Corrole through Valence Tautomerization

    OpenAIRE

    Bougher, Curt J.; Abu‐Omar, Mahdi M.

    2016-01-01

    Abstract The kinetics of formation of the valence tautomers (tpfc⋅)MnIV(O−LA)] n+ [where LA=ZnII, CaII, ScIII, YbIII, B(C6F5)3, and trifluoroacetic acid (TFA); tpfc=5,10,15‐tris(pentafluorophenyl) corrole] from (tpfc)MnV(O) were followed by UV/Vis spectroscopy, giving second‐order rate constants ranging over five orders of magnitude from 10−2 for Ca to 103  m −1 s−1 for Sc. Hydrogen atom transfer (HAT) rates from 2,4‐di‐tert‐butyl phenol (2,4‐DTBP) to the various Lewis acid valence tautomers ...

  3. Environment assisted crack growth in nickel-base superalloys at elevated temperature

    Science.gov (United States)

    Evans, Jeffrey Lee

    The environmental effect on the fatigue crack growth rate of Ni-base superalloys at elevated temperature was evaluated in this study. A set of crack growth tests was performed on the turbine disk alloy ME3 at 704°C (1300°F) in vacuum and in air at 0 and 10 second hold times using two microstructures developed with two different cooling rates from the solution heat treat temperature. Fatigue crack growth tests were also conducted at 25°C (77°F) with the two microstructures. Also, a set of oxidation experiments was conducted in order to evaluate the high temperature oxidation behavior of ME3. The microstructure was analyzed and the main differences between the two cooling rates were in the amounts of minor phase particles and size of secondary gamma prime particles. The crack growth rate results suggest that there is no measurable effect of environment or microstructure at room temperature. For the tests conducted in air at elevated temperature, both hold time and microstructural effects were evident. A coupling effect was also observed between the microstructure and the environment. The samples that were slow cooled, and had larger secondary gamma prime particles, had slower crack growth rates and less intergranular fracture in air than the fast cooled samples. A possible explanation for this would be excess free chromium available along grain boundaries due to its low solubility in gamma prime, providing for greater oxidation resistance. An elevated temperature fatigue crack growth rate model for Ni-base superalloys is also proposed.

  4. Recent trends in robot-assisted therapy environments to improve real-life functional performance after stroke

    Directory of Open Access Journals (Sweden)

    Johnson Michelle J

    2006-12-01

    Full Text Available Abstract Upper and lower limb robotic tools for neuro-rehabilitation are effective in reducing motor impairment but they are limited in their ability to improve real world function. There is a need to improve functional outcomes after robot-assisted therapy. Improvements in the effectiveness of these environments may be achieved by incorporating into their design and control strategies important elements key to inducing motor learning and cerebral plasticity such as mass-practice, feedback, task-engagement, and complex problem solving. This special issue presents nine articles. Novel strategies covered in this issue encourage more natural movements through the use of virtual reality and real objects and faster motor learning through the use of error feedback to guide acquisition of natural movements that are salient to real activities. In addition, several articles describe novel systems and techniques that use of custom and commercial games combined with new low-cost robot systems and a humanoid robot to embody the " supervisory presence" of the therapy as possible solutions to exercise compliance in under-supervised environments such as the home.

  5. A strategy to assist management in workforce engagement and employee retention in the high tech engineering environment.

    Science.gov (United States)

    Kennedy, Elizabeth; Daim, Tugrul U

    2010-11-01

    Many companies use survey methods in an attempt to gauge employees' attitudes and opinions toward the company. These attitudes and opinions are directly related to an employee's engagement within the company. In many instances, employees wait in vain for the survey response and the subsequent employer actions, but the truth is sometimes management does not know what to do with the results. For this reason, we theorize that this type of survey, typically utilizing the Likert-scale, is not adequately assisting management in addressing employee engagement and retention issues. For instance, in many occasions, once the survey results are tabulated, companies are doing little or nothing to address the issues. In fact, far too many companies make the mistake of conducting employee engagement surveys, and then ignore the answers. Thus, we propose that a company should take advantage of the survey results, and utilize them to provide data to bridge employees' needs and goals with stakeholders' responsibilities and goals by refining and incorporating them into a hierarchical decision model (HDM). Thus, this would essentially be utilizing the quantitative data to determine what to measure qualitatively. We use a case from the high tech industry, specifically focusing on the engineering environment. Engineering environments are known to be more creative and such approaches would be more beneficial. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  6. Slow Strain Rate Tensile Testing to Assess the Ability of Superalloys to Resist Environment-Assisted Intergranular Cracking

    Science.gov (United States)

    Gabb, Timothy P.; Telesman, Jack; Banik, Anthony; McDevitt, Erin

    2014-01-01

    Intergranular fatigue crack initiation and growth due to environmental degradation, especially at notched features, can often limit the fatigue life of disk superalloys at high temperatures. For clear comparisons, the effects of alloy composition on cracking in air needs to be understood and compared separately from variables associated with notches and cracks such as effective stress concentration, plastic flow, stress relaxation, and stress redistribution. The objective of this study was to attempt using simple tensile tests of specimens with uniform gage sections to compare the effects of varied alloy composition on environment-assisted cracking of several powder metal and cast and wrought superalloys including ME3, LSHR, Udimet 720, ATI 718Plus alloy, Haynes 282, and Inconel 740. Slow and fast strain-rate tensile tests were found to be a useful tool to compare propensities for intergranular surface crack initiation and growth. The effects of composition and heat treatment on tensile fracture strain and associated failure modes were compared. Environment interactions were determined to often limit ductility, by promoting intergranular surface cracking. The response of various superalloys and heat treatments to slow strain rate tensile testing varied substantially, showing that composition and microstructure can significantly influence environmental resistance to cracking.

  7. Properties of Erbium Doped Hydrogenated Amorphous Carbon Layers Fabricated by Sputtering and Plasma Assisted Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2008-01-01

    Full Text Available We report about properties of carbon layers doped with Er3+ ions fabricated by Plasma Assisted Chemical Vapor Deposition (PACVD and by sputtering on silicon or glass substrates. The structure of the samples was characterized by X-ray diffraction and their composition was determined by Rutherford Backscattering Spectroscopy and Elastic Recoil Detection Analysis. The Absorbance spectrum was taken in the spectral range from 400 nm to 600 nm. Photoluminescence spectra were obtained using two types of Ar laser (λex=514.5 nm, lex=488 nm and also using a semiconductor laser (λex=980 nm. Samples fabricated by magnetron sputtering exhibited typical emission at 1530 nm when pumped at 514.5 nm. 

  8. Environment

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the origin...... and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....

  9. Effects of Ligand Environment in Zr(IV) Assisted Peptide Hydrolysis.

    Science.gov (United States)

    Zhang, Tingting; Sharma, Gaurav; Paul, Thomas J; Hoffmann, Zachary; Prabhakar, Rajeev

    2017-05-22

    In this DFT study, activities of 11 different N2O4, N2O3, and NO2 core containing Zr(IV) complexes, 4,13-diaza-18-crown-6 (I'N2O4), 1,4,10-trioxa-7,13-diazacyclopentadecane (I'N2O3), and 2-(2-methoxy)ethanol (I'NO2), respectively, and their analogues in peptide hydrolysis have been investigated. Based on the experimental information, these molecules were created by altering protonation states (singly protonated, doubly protonated, or doubly deprotonated) and number of their ligands. The energetics of the I'N2O4, and I'NO2 and their analogues predicted that both stepwise and concerted mechanisms occurred either with similar barriers, or the latter was more favorable than the former. They also showed that the doubly deprotonated form hydrolyzed the peptide bond with substantially lower barriers than the barriers for other protonation states. For NO2 core possessing complexes, Zr-(NO2)(OH(H))(H2O/OH)n for n = 1-3, the hydroxyl group containing molecules were found to be more reactive than their water ligand possessing counterparts. The barriers for these complexes reduced with an increase in the coordination number (6-8) of the Zr(IV) ion. Among all 11 molecules, the NO2 core possessing and two hydroxyl group containing I'DNO2-2H complex was found to be the most reactive complex with a barrier of 28.9 kcal/mol. Furthermore, barriers of 27.5, 28.9, and 32.0 kcal/mol for hydrolysis of Gly-Glu (negative), Gly-Gly (neutral), and Gly-Lys (positive) substrates, respectively, by this complex were in agreement with experiments. The activities of these complexes were explained in terms of basicity of their ligand environment and nucleophilicity of the Zr(IV) center using metal-ligand distances, charge on the metal ion, and the metal-nucleophile distance as parameters. These results provide a deeper understanding of the functioning of these complexes and will help design Zr(IV)-based synthetic metallopeptidases.

  10. Investigation of zinc recovery by hydrogen reduction assisted pyrolysis of alkaline and zinc-carbon battery waste.

    Science.gov (United States)

    Ebin, Burçak; Petranikova, Martina; Steenari, Britt-Marie; Ekberg, Christian

    2017-10-01

    Zinc (Zn) recovery from alkaline and zinc-carbon (Zn-C) battery waste were studied by a laboratory scale pyrolysis process at a reaction temperature of 950°C for 15-60min residence time using 5%H2(g)-N2(g) mixture at 1.0L/min gas flow rate. The effect of different cooling rates on the properties of pyrolysis residue, manganese oxide particles, were also investigated. Morphological and structural characterization of the produced Zn particles were performed. The battery black mass was characterized with respect to the properties and chemical composition of the waste battery particles. The thermodynamics of the pyrolysis process was studied using the HSC Chemistry 5.11 software. A hydrogen reduction reaction of the battery black mass (washed with Milli-Q water) takes place at the chosen temperature and makes it possible to produce fine Zn particles by rapid condensation following the evaporation of Zn from the pyrolysis batch. The amount of Zn that can be separated from the black mass increases by extending the residence time. Recovery of 99.8% of the Zn was achieved at 950°C for 60min residence time using 1.0L/min gas flow rate. The pyrolysis residue contains MnO and Mn2O3 compounds, and the oxidation state of manganese can be controlled by cooling rate and atmosphere. The Zn particles exhibit spherical and hexagonal particle morphology with a particle size varying between 200nm and 3µm. However the particles were formed by aggregation of nanoparticles which are primarily nucleated from the gas phase. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Simple electro-assisted immobilization of ciprofloxacin on carbon nanotube modified electrodes: its selective hydrogen peroxide electrocatalysis.

    Science.gov (United States)

    Sornambikai, Sundaram; Kumar, Annamalai Senthil

    2014-09-01

    Ciprofloxacin (Cf) is a synthetic fourth generation fluoroquinolone class antibiotic used for the treatment of gram-positive, gram-negative and mycobacterium species infections. Electrochemical characteristic of the Cf antibiotic on carbon nanotube modified glassy carbon electrode (GCE/CNT) in pH 7 phosphate buffer solution has been investigated. Electrochemically oxidized radical byproduct of the Cf drug, which is formed as intermediate, gets immobilized on the GCE/CNT (GCE/Cf@CNT) and showed stable and well defined surface confined redox peak at -0.220 V versus Ag/AgCl. Control electrochemical experiment with unmodified GCE failed to show any such immobilization and redox features. Physicochemical characterizations of the Cf@CNT by transmission electron microscope, scanning electron microscope, infrared spectroscopy, UV-Vis and gas chromatography coupled mass spectroscopic analyses of Cf@CNT collectively revealed presence of native form of the Cf antibiotic molecule onto the CNT. The interaction between the Cf molecule and the CNT tubes are revealed from the decreased intensity in the Raman spectrum. The GCE/Cf@CNT showed excellent electrocatalytic response to hydrogen peroxide reduction reaction in pH 7 phosphate buffer solution. Amperometric i-t analysis for the detection of H2O2 showed a current linearity plot upto [H2O2] = 200 μM at an applied potential - 0.1 V versus Ag/AgCl with a current sensitivity value 678 μA mM(-1) cm(-2). No interferences were noticed with ascorbic acid, uric acid, cysteine and nitrite. The present study can be highly helpful to understand the interaction between the Cf and H2O2 in physiological systems and for the removal of Cf from the antibiotic polluted water samples especially in the aquaculture and agricultural systems.

  12. Template-assisted hydrothermally obtained titania-ceria composites and their application as catalysts in ethyl acetate oxidation and methanol decomposition with a potential for sustainable environment protection

    Science.gov (United States)

    Tsoncheva, Tanya; Mileva, Alexandra; Issa, Gloria; Dimitrov, Momtchil; Kovacheva, Daniela; Henych, Jiří; Scotti, Nicola; Kormunda, Martin; Atanasova, Genoveva; Štengl, Vaclav

    2017-02-01

    High surface area mesoporous ceria-titania binary materials with high Lewis acidity and improved reduction properties were synthesized using template assisted hydrothermal technique. The obtained materials were characterized by low temperature nitrogen physisorption, XRD, SEM, TEM, Raman, UV-vis, XPS, FTIR, FTIR of adsorbed pyridine and thermo-programmed reduction with hydrogen. Their catalytic activity was tested in total oxidation of ethyl acetate and methanol decomposition to CO and hydrogen with a potential application in VOCs elimination and alternative fuels, respectively. The structural changes in the binary materials, which could be tuned by the variation in the Ce/Ti ratio and the temperature of hydrothermal treatment, provoked significant changes in their textural, surface and redox properties, which is in close relation to the catalytic activity and selectivity in various catalytic processes. The intimate contact between the individual oxides results in the formation of different catalytic active sites and their role in the studied catalytic reactions was discussed in details.

  13. Contributing influences of work environment on sleep quantity and quality of nursing assistants in long-term care facilities: A cross-sectional study.

    Science.gov (United States)

    Zhang, Yuan; Punnett, Laura; McEnany, Geoffry Phillips; Gore, Rebecca

    2016-01-01

    The effect of shift work on nurses' sleep is well-studied, but there are other challenging aspects of health care work that might also affect the sleep of direct caregivers. This study examined the influence of the long-term care work environment on sleep quantity and quality of nursing assistants. A cross-sectional survey collected data from 650 nursing assistants in 15 long-term care facilities; 46% reported short sleep duration and 23% reported poor sleep quality. A simple additive index of the number of beneficial work features (up to 7) was constructed for analysis with Poisson regression. With each unit increase of beneficial work features, nursing assistants were 7% less likely to report short sleep duration and 17% less likely to report poor sleep quality. These results suggest that effective workplace interventions should address a variety of work stressors, not only work schedule arrangements, in order to improve nursing assistants' sleep health.

  14. Evaluation Of Methods To Measure Hydrogen Generation Rate In A Shielded Cell Environment And A Method Recommendation

    Energy Technology Data Exchange (ETDEWEB)

    Stone, M. E.

    2012-11-07

    The purpose of this document is to describe the current state of the art for determination of hydrogen generation rates of radioactive slurries and solutions to provide a basis for design, fabrication, testing, and implementation of a measurement method for Hydrogen Generation Rate (HGR) during qualification of waste feeds for the Hanford Waste Treatment and Immobilization Plant (WTP). The HGR measurement will be performed on samples of the Low Activity Waste (LAW) and High Level Waste (HLW) staged waste feeds for the WTP as well as on samples from selected unit operations testing during the qualification program. SRNL has performed a review of techniques utilized to measure HGR of high level radioactive waste slurries, evaluated the Hanford 222-S Laboratory method for measurement of hydrogen, and reviewed the hydrogen generation rate models for Hanford waste.Based on the literature review, method evaluation, and SRNL experience with measuring hydrogen generation rate, SRNL recommends that a continuous flow system with online gas analysis be used as the HGR measurement method during waste qualification.

  15. Evaluation Of Methods To Measure Hydrogen Generation Rate In A Shielded Cell Environment And A Method Recommendation

    Energy Technology Data Exchange (ETDEWEB)

    Stone, M. E.

    2012-11-07

    The purpose of this document is to describe the current state of the art for determination of hydrogen generation rates of radioactive slurries and solutions to provide a basis for design, fabrication, testing, and implementation of a measurement method for Hydrogen Generation Rate (HGR) during qualification of waste feeds for the Hanford Waste Treatment and Immobilization Plant (WTP). The HGR measurement will be performed on samples of the Low Activity Waste (LAW) and High Level Waste (HLW) staged waste feeds for the WTP as well as on samples from selected unit operations testing during the qualification program. SRNL has performed a review of techniques utilized to measure HGR of high level radioactive waste slurries, evaluated the Hanford 222-S Laboratory method for measurement of hydrogen, and reviewed the hydrogen generation rate models for Hanford waste.Based on the literature review, method evaluation, and SRNL experience with measuring hydrogen generation rate, SRNL recommends that a continuous flow system with online gas analysis be used as the HGR measurement method during waste qualification.

  16. The Effect of Web Assisted Learning with Emotional Intelligence Content on Students' Information about Energy Saving, Attitudes towards Environment and Emotional Intelligence

    Science.gov (United States)

    Ercan, Orhan; Ural, Evrim; Köse, Sinan

    2017-01-01

    For a sustainable world, it is very important for students to develop positive environmental attitudes and to have awareness of energy use. The study aims to investigate the effect of web assisted instruction with emotional intelligence content on 8th grade students' emotional intelligence, attitudes towards environment and energy saving, academic…

  17. Highly selective hydrogenation of CO2 to methanol over CuO-ZnO-ZrO2 catalysts prepared by a surfactant-assisted co-precipitation method

    Science.gov (United States)

    Li, Li; Mao, Dongsen; Yu, Jun; Guo, Xiaoming

    2015-04-01

    A series of CuO-ZnO-ZrO2 catalysts are synthesized by a surfactant-assisted co-precipitation method and tested for the synthesis of methanol from CO2 hydrogenation. The effects of calcination temperature on the physicochemical properties of as-prepared catalysts are investigated extensively by TG-DSC, N2 adsorption/desorption, XRD, N2O chemisorption, SEM/TEM, EDX, XPS, TPR, H2-TPD and CO2-TPD techniques. The results show that the size of copper particles increases with the increase in calcination temperature, leading to the decrease in turnover frequency (TOF) for methanol formation. Moreover, compared with the counterparts prepared by the conventional co-precipitation method, the CuO-ZnO-ZrO2 catalysts prepared by this novel method show significantly high methanol selectivity. The superior property of the prepared CuO-ZnO-ZrO2 catalyst can be attributed to the formation of more amounts of Cu-ZnOx and/or Cu-ZrOx species resulted from the homogeneous element distribution, intimate interface contact of Cu species with ZnO and/or ZrO2, and to porous structure with larger pore size.

  18. Biomolecule-assisted synthesis of defect-mediated Cd1-xZnxS/MoS2/graphene hollow spheres for highly efficient hydrogen evolution.

    Science.gov (United States)

    Du, Ruifeng; Zhang, Yihe; Li, Baoying; Yu, Xuelian; Liu, Huijuan; An, Xiaoqiang; Qu, Jiuhui

    2016-06-28

    Moderate efficiency and the utilization of noble metal cocatalysts are the key factors that restrict the large-scale application of photocatalytic hydrogen production. To develop more efficient photocatalysts based on earth abundant elements, either a new material strategy or a fundamental understanding of the semiconductor/cocatalyst interfaces is highly desirable. In this paper, we studied the feasibility of in situ formation of defect-rich cocatalysts on graphene-based photocatalysts. A facile biomolecule-assisted strategy was used to self-assmble Cd1-xZnxS/MoS2/graphene hollow spheres. The defect-mediated cocatalyst and synergetic charge transfer around heterostructured interfaces exhibit a significant impact on the visible-light-driven photocatalytic activity of multicomponent solid solutions. With engineered interfacial defects, Cd0.8Zn0.2S/MoS2/graphene hollow spheres exhibited a 63-fold improved H2 production rate, which was even 2 and 3.8 times higher than those of CdS/MoS2/graphene hollow spheres and Cd0.8Zn0.2S/Pt. Therefore, our research provides a promising approach for the rational design of high-efficiency and low-cost photocatalysts for solar fuel production.

  19. Free MoS2 Nanoflowers Grown on Graphene by Microwave-Assisted Synthesis as Highly Efficient Non-Noble-Metal Electrocatalysts for the Hydrogen Evolution Reaction

    Science.gov (United States)

    Cao, Jiamu; Zhang, Xuelin; Zhang, Yufeng; Zhou, Jing; Chen, Yinuo; Liu, Xiaowei

    2016-01-01

    Advanced approaches to preparing non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER) are considered to be a significant breakthrough in promoting the exploration of renewable resources. In this work, a hybrid material of MoS2 nanoflowers (NFs) on reduced graphene oxide (rGO) was synthesized as a HER catalyst via an environmentally friendly, efficient approach that is also suitable for mass production. Small-sized MoS2 NFs with a diameter of ca. 190 nm and an abundance of exposed edges were prepared by a hydrothermal method and were subsequently supported on rGO by microwave-assisted synthesis. The results show that MoS2 NFs were distributed uniformly on the remarkably reduced GO and preserved the outstanding original structural features perfectly. Electrochemical tests show that the as-prepared hybrid material exhibited excellent HER activity, with a small Tafel slope of 80 mV/decade and a low overpotential of 170 mV. PMID:27556402

  20. Solvent-Assisted Oxygen Incorporation of Vertically Aligned MoS2 Ultrathin Nanosheets Decorated on Reduced Graphene Oxide for Improved Electrocatalytic Hydrogen Evolution.

    Science.gov (United States)

    Liu, Aiping; Zhao, Li; Zhang, Junma; Lin, Liangxu; Wu, Huaping

    2016-09-28

    Three-dimensional oxygen-incorporated MoS2 ultrathin nanosheets decorated on reduced graphene oxide (O-MoS2/rGO) had been successfully fabricated through a facile solvent-assisted hydrothermal method. The origin of the incorporated oxygen and its incorporation mechanism into MoS2 were carefully investigated. We found that the solvent N,N-dimethylformamide (DMF) was the key as the reducing agent and the oxygen donor, expanding interlayer spaces and improving intrinsic conductivity of MoS2 sheets (modulating its electronic structure and vertical edge sites). These O dopants, vertically aligned edges and decoration with rGO gave effectively improved double-layer capacitance and catalytic performance for hydrogen evolution reaction (HER) of MoS2. The prepared O-MoS2/rGO catalysts showed an exceptional small Tafel slope of 40 mV/decade, a high current density of 20 mA/cm(2) at the overpotential of 200 mV and remarkable stability even after 2000th continuous HER test in the acid media.

  1. Comparison of walking overground and in a Computer Assisted Rehabilitation Environment (CAREN in individuals with and without transtibial amputation

    Directory of Open Access Journals (Sweden)

    Gates Deanna H

    2012-11-01

    Full Text Available Abstract Background Due to increased interest in treadmill gait training, recent research has focused on the similarities and differences between treadmill and overground walking. Most of these studies have tested healthy, young subjects rather than impaired populations that might benefit from such training. These studies also do not include optic flow, which may change how the individuals integrate sensory information when walking on a treadmill. This study compared overground walking to treadmill walking in a computer assisted virtual reality environment (CAREN in individuals with and without transtibial amputations (TTA. Methods Seven individuals with traumatic TTA and 27 unimpaired controls participated. Subjects walked overground and on a treadmill in a CAREN at a normalized speed. The CAREN applied optic flow at the same speed that the subject walked. Temporal-spatial parameters, full body kinematics, and kinematic variability were collected during all trials. Results Both subject groups decreased step time and control subjects decreased step length when walking in the CAREN. Differences in lower extremity kinematics were small (○ and did not exceed the minimal detectable change values for these measures. Control subjects exhibited decreased transverse and frontal plane range of motion of the pelvis and trunk when walking in the CAREN, while patients with TTA did not. Both groups exhibited increased step width variability during treadmill walking in the CAREN, but only minor changes in kinematic variability. Conclusions The results of this study suggest that treadmill training in a virtual environment should be similar enough to overground that changes should carry over. Caution should be made when comparing step width variability and step time results from studies utilizing a treadmill to those overground.

  2. Energy systems programs funded by the Assistant Secretary for Environment, Safety and Health: FY 1993--FY 1994

    Energy Technology Data Exchange (ETDEWEB)

    Buttram, A.W. [ed.

    1994-12-31

    This document presents an overview of work at Martin Marietta Energy Systems, Inc., (Energy Systems) during FY 1993--FY 1994 that was funded by the Department of Energy`s (DOE`s) Assistant Secretary for Environment, Safety and Health (ASEH). To illustrate the programmatic breadth of Energy Systems and to establish the context within which this work was accomplished, this document also includes representative descriptions of ASEH-related work at Energy Systems done for other sponsors. Activities for ASEH cover a wide variety of subjects that are geared towards the environmental, safety, and health aspects of DOE operations. Subjects include the following: environmental compliance, environmental guidance, environmental audits, NEPA oversight, epidemiology and health surveillance, transportation and packaging safety, safety and quality assurance; technical standards, performance indicators, occurrence reporting, health physics instrumentation, risk management, security evaluations, and medical programs. The technical support section describes work in progress for ASEH, including specific program accomplishments. The work for others section describes work for non-ASEH sponsors that reinforces and supplements the ASEH work. Appendix A includes a list of FY 1993--FY 1994 publications related to the ASEH work.

  3. A simulation environment for assisting system design of coherent laser doppler wind sensor for active wind turbine pitch control

    Science.gov (United States)

    Shinohara, Leilei; Pham Tran, Tuan Anh; Beuth, Thorsten; Umesh Babu, Harsha; Heussner, Nico; Bogatscher, Siegwart; Danilova, Svetlana; Stork, Wilhelm

    2013-05-01

    In order to assist a system design of laser coherent Doppler wind sensor for active pitch control of wind turbine systems (WTS), we developed a numerical simulation environment for modeling and simulation of the sensor system. In this paper we present this simulation concept. In previous works, we have shown the general idea and the possibility of using a low cost coherent laser Doppler wind sensing system for an active pitch control of WTS in order to achieve a reduced mechanical stress, increase the WTS lifetime and therefore reduce the electricity price from wind energy. Such a system is based on a 1.55μm Continuous-Wave (CW) laser plus an erbium-doped fiber amplifier (EDFA) with an output power of 1W. Within this system, an optical coherent detection method is chosen for the Doppler frequency measurement in megahertz range. A comparatively low cost short coherent length laser with a fiber delay line is used for achieving a multiple range measurement. In this paper, we show the current results on the improvement of our simulation by applying a Monte Carlo random generation method for positioning the random particles in atmosphere and extend the simulation to the entire beam penetrated space by introducing a cylindrical co-ordinate concept and meshing the entire volume into small elements in order to achieve a faster calculation and gain more realistic simulation result. In addition, by applying different atmospheric parameters, such as particle sizes and distributions, we can simulate different weather and wind situations.

  4. Photocatalytic hydrogen generation over porous ZnIn{sub 2}S{sub 4} microspheres synthesized via a CPBr-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xuefeng, E-mail: bxuefeng@163.net [Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin 150040 (China); School of Chemistry and Materials, Heilongjiang University, Harbin 150070 (China); Li, Jinshu [School of Chemistry and Materials, Heilongjiang University, Harbin 150070 (China)

    2011-07-15

    Graphical abstract: ZnIn{sub 2}S{sub 4} porous microspheres were synthesized via a cetylpyridinium bromide (CPBr)-assisted hydrothermal method. It could be seen from the SEM image that the flowerlike microspheres were composed of numerous nanosheets. Many slit-like pores were formed among the curved nanosheets. The porous structure benefited the adsorption of reactants, the diffuseness of products, the charge separation on surface, the transfer of the interfacial charge carriers and the charge carrier trapping. And porous ZnIn{sub 2}S{sub 4} photocatalyst exhibited higher photocatalytic activity than nonporous ZnIn{sub 2}S{sub 4} material. Highlights: {yields} A series of unique flower-like porous ZnIn{sub 2}S{sub 4} microspheres of hexagonal crystal phase as efficient visible-light photocatalysts have been synthesized through CPBr-assisted hydrothermal method. {yields} The CPBr addition would visibly influence the self-assemble growing and the crystal structure including the position and intensity of some peaks. {yields} We also found that the pH value plays a crucial role in the formation of ZnIn{sub 2}S{sub 4} porous microspheres and the influence of the pH on the structure of product has been first reported in our paper. {yields} The results showed that our as-synthesized porous ZnIn{sub 2}S{sub 4} microspheres possessed a specific surface area of 165.4 m{sup 2} g{sup -1} and performed higher visible-light photocatalytic activity than bulk ZnIn{sub 2}S{sub 4} for hydrogen evolution. The maximum H{sub 2} evolution rate of ZnIn{sub 2}S{sub 4} reaches 1544.8 {mu}mol/(h g). -- Abstract: Hexagonal ZnIn{sub 2}S{sub 4} porous microspheres were synthesized via a cetylpyridinium bromide (CPBr)-assisted hydrothermal method. The structure, morphology and optical property of these prepared products were characterized by wide angle X-ray diffraction (WAXRD), small angle X-ray diffraction (SAXRD), UV-Vis diffusive reflectance spectroscopy (DRS), field emission scanning

  5. Effect of short-term infusion of hydrogen on enteric gas production and rumen environment in dairy cows

    NARCIS (Netherlands)

    Olijhoek, Dana; Hellwing, A.L.F.; Weisbjerg, M.R.; Dijkstra, J.; Højberg, A.L.; Lund, Peter

    2016-01-01

    Methane (CH4) production by rumen methanogens lowers hydrogen (H2) pressure and, in theory, prevents inhibition of fermentation processes by H2 accumulation. The present study aimed at examining effects of short-term H2 infusion on CH4 productio

  6. Microoxic Niches within the Thylakoid Stroma of Air-Grown Chlamydomonas reinhardtii Protect [FeFe]-Hydrogenase and Support Hydrogen Production under Fully Aerobic Environment1[OPEN

    Science.gov (United States)

    Liran, Oded; Milrad, Yuval; Eilenberg, Haviva; Weiner, Iddo

    2016-01-01

    Photosynthetic hydrogen production in the microalga Chlamydomonas reinhardtii is catalyzed by two [FeFe]-hydrogenase isoforms, HydA1 and HydA2, both irreversibly inactivated upon a few seconds exposure to atmospheric oxygen. Until recently, it was thought that hydrogenase is not active in air-grown microalgal cells. In contrast, we show that the entire pool of cellular [FeFe]-hydrogenase remains active in air-grown cells due to efficient scavenging of oxygen. Using membrane inlet mass spectrometry, 18O2 isotope, and various inhibitors, we were able to dissect the various oxygen uptake mechanisms. We found that both chlororespiration, catalyzed by plastid terminal oxidase, and Mehler reactions, catalyzed by photosystem I and Flavodiiron proteins, significantly contribute to oxygen uptake rate. This rate is considerably enhanced with increasing light, thus forming local anaerobic niches at the proximity of the stromal face of the thylakoid membrane. Furthermore, we found that in transition to high light, the hydrogen production rate is significantly enhanced for a short duration (100 s), thus indicating that [FeFe]-hydrogenase functions as an immediate sink for surplus electrons in aerobic as well as in anaerobic environments. In summary, we show that an anaerobic locality in the chloroplast preserves [FeFe]-hydrogenase activity and supports continuous hydrogen production in air-grown microalgal cells. PMID:27443604

  7. Hydrogen atom in a quantum plasma environment under the influence of Aharonov-Bohm flux and electric and magnetic fields

    CERN Document Server

    Falaye, Babatunde James; Silva-Ortigoza, Ramón; Dong, Shi-Hai

    2016-01-01

    This study presents the confinement influences of Aharonov-Bohm-flux (AB-flux), electric and magnetic fields directed along $z$-axis and encircled by quantum plasmas, on the hydrogen atom. The all-inclusive effects result to a strongly attractive system while the localizations of quantum levels change and the eigenvalues decrease. We find that, the combined effect of the fields is stronger than solitary effect and consequently, there is a substantial shift in the bound state energy of the system. We also find that to perpetuate a low-energy medium for hydrogen atom in quantum plasmas, strong electric field and weak magnetic field are required, where AB-flux field can be used as a regulator. The application of perturbation technique utilized in this paper is not restricted to plasma physics, it can also be applied in molecular physics.

  8. Environmental fatigue of an Al-Li-Cu alloy. I - Intrinsic crack propagation kinetics in hydrogenous environments

    Science.gov (United States)

    Piascik, Robert S.; Gangloff, Richard P.

    1991-01-01

    Deleterious environmental effects on steady-state, intrinsic fatigue crack propagation (FCP) rates (da/dN) in peak aged Al-Li-Cu alloy 2090 are established by electrical potential monitoring of short cracks with programmed constant delta K and K(sub max) loading. The da/dN are equally unaffected by vacuum, purified helium, and oxygen but are accelerated in order of decreasing effectiveness of aqueous 1 percent NaCl with anodic polarization, pure water vapor, moist air, and NaCl with cathodic polarization. While da/dN depends on delta K(sup 4.0) for the inert gases, water vapor and chloride induced multiple power-laws, and a transition growth rate 'plateau'. Environmental effects are strongest at low delta K. Crack tip damage is ascribed to hydrogen embrittlement because of the following: (1) accelerated da/dN due to part-per-million levels of H2O without condensation; (2) impeded molecular flow model predictions of the measured water vapor pressure dependence of da/dN as affected by mean crack opening; (3) the lack of an effect of film-forming O2; (4) the likelihood for crack tip hydrogen production in NaCl; and (5) the environmental and delta K-process zone volume dependencies of the microscopic cracking modes. For NaCl, growth rates decrease with decreasing loading frequency, with the addition of passivating Li2CO3, and upon cathodic polarization. These variables increase crack surface film stability to reduce hydrogen entry efficiency. The hydrogen environmental FCP resistance of 2090 is similar to other 2000 series alloys and is better than 7075.

  9. Environmental fatigue of an Al-Li-Cu alloy. Part 1: Intrinsic crack propagation kinetics in hydrogenous environments

    Science.gov (United States)

    Piascik, Robert S.; Gangloff, Richard P.

    1991-01-01

    Deleterious environmental effects on steady-state, intrinsic fatigue crack propagation (FCP) rates (da/dN) in peak aged Al-Li-Cu alloy 2090 are established by electrical potential monitoring of short cracks with programmed constant delta K and K(sub max) loading. The da/dN are equally unaffected by vacuum, purified helium, and oxygen but are accelerated in order of decreasing effectiveness by aqueous 1 percent NaCl with anodic polarization, pure water vapor, moist air, and NaCl with cathodic polarization. While da/dN depends on delta K(sup 4.0) for the inert gases, water vapor and chloride induced multiple power-laws, and a transition growth rate 'plateau'. Environmental effects are strongest at low delta K. Crack tip damage is ascribed to hydrogen embrittlement because of the following: (1) accelerated da/dN due to part-per-million levels of H2O without condensation; (2) impeded molecular flow model predictions of the measured water vapor pressure dependence of da/dN as affected by mean crack opening; (3) the lack of an effect of film-forming O2; (4) the likelihood for crack tip hydrogen production in NaCl, and (5) the environmental and delta K-process zone volume dependencies of the microscopic cracking modes. For NaCl, growth rates decrease with decreasing loading frequency, with the addition of passivating Li2CO3, and upon cathodic polarization. These variables increase crack surface film stability to reduce hydrogen entry efficiency. The hydrogen environmental FCP resistance of 2090 is similar to other 2000 series alloys and is better than 7075.

  10. Solid oxide fuel cell anode degradation by the effect of hydrogen chloride in stack and single cell environments

    Science.gov (United States)

    Madi, Hossein; Lanzini, Andrea; Papurello, Davide; Diethelm, Stefan; Ludwig, Christian; Santarelli, Massimo; Van herle, Jan

    2016-09-01

    The poisoning effect by hydrogen chloride (HCl) on state-of-the-art Ni anode-supported solid oxide fuel cells (SOFCs) at 750 °C is evaluated in either hydrogen or syngas fuel. Experiments are performed on single cells and short stacks and HCl concentration in the fuel gas is increased from 1 ppm(v) up to 1000 ppm(v) at different current densities. Characterization methods such as cell voltage monitoring vs. time and electrochemical impedance response analysis (distribution of relaxation times (DRT), equivalent electrical circuit) are used to identify the prevailing degradation mechanism. Single cell experiments revealed that the poisoning is more severe when feeding with hydrogen than with syngas. Performance loss is attributed to the effects of HCl adsorption onto nickel surfaces, which lowered the catalyst activity. Interestingly, in syngas HCl does not affect stack performance even at concentrations up to 500 ppm(v), even when causing severe corrosion of the anode exhaust pipe. Furthermore, post-test analysis suggests that chlorine is present on the nickel particles in the form of adsorbed chlorine, rather than forming a secondary phase of nickel chlorine.

  11. Rapid screening of stainless steels for environmentally assisted cracking in H{sub 2}S/CO{sub 2}/Cl{sup {minus}} environments using the slow strain rate test

    Energy Technology Data Exchange (ETDEWEB)

    Joia, C.J.B.M. [PETROBRAS, Rio de Janeiro (Brazil). Centre de Pesquisas; Small, A.L.L.T.; Ponciano, J.A.C. [Univ. Federal do Rio de Janeiro (Brazil); Kane, R.D. [CLI International, Inc., Houston, TX (United States)

    1997-08-01

    Stress corrosion cracking (SCC) and hydrogen embrittlement (HE) susceptibility of three different steels were determined using the methodology of the slow strain rate (SSR) testing as currently discussed within ASTM G129 and more specifically in the proposed NACE T-1F-9e test method. The materials included 13% Cr and 13%Cr-5% Ni-2% Mo martensitic stainless steels and 22%CR-5%Ni-3%Mo (22Cr) duplex stainless steel. They were tested under slow strain rate experiments, conducted in simulated service environments containing H{sub 2}S, CO{sub 2} and Cl{sup {minus}} containing brine. The parameters selected to quantify the susceptibility to environmentally assisted cracking (EAC) were ductility (as measured by elongation and reduction in area), fracture energy (as measured by the area under stress versus strain curves) and time to failure. These parameters were analyzed considering the ratio of the property in the corrosive environment to the result in an inert environment at the same temperature. The classification of fracture type defined by the proposed NACE T-1F-9 test method was also used. It was concluded that the SSR testing was able to screen corrosion resistant alloys for stress corrosion cracking in sour oil field service. It was shown that, although 22Cr (duplex steel) had a higher corrosion resistance compared to 13Cr-5Ni-2Mo and of 13Cr martensitic stainless steels, there was a region, pH above 4, temperatures up to 150 C, H{sub 2}S partial pressure below 1.5 psia and CO{sub 2} partial pressure of 130 psia, where 13Cr failed but where 13Cr-5Ni-2Mo gave acceptable results. It was concluded that pH and temperature of the environment work together and play an important role on the mechanism of failure.

  12. Solid H2 versus solid noble-gas environment: Influence on photoinduced hydrogen-atom transfer in matrix-isolated 4(3H)-pyrimidinone

    Science.gov (United States)

    Lapinski, Leszek; Nowak, Maciej J.; Rostkowska, Hanna

    2017-03-01

    UV-induced transformations have been studied for 4(3H)-pyrimidinone monomers isolated in low-temperature Ar, Ne, n-D2, and n-H2 matrices. The observed photochemical behavior of the compound drastically depended on the solid matrix environment. For 4(3H)-pyrimidinone isolated in solid Ar, the UV-induced phototautomeric transformation was clearly the dominating process, leading to a nearly quantitative conversion of the oxo reactant into the hydroxy product. For solid Ne environment, the oxo → hydroxy transformation was still the major photoprocess, but yielding less of the hydroxy product (ca. 64% of the yield in solid Ar). For 4(3H)-pyrimidinone isolated in solid n-H2, the oxo → hydroxy phototautomeric conversion did not occur (or occurred at a very tiny scale). Also for deuterated 4(3D)-pyrimidinone isolated in solid hydrogen, the analogous oxo → deuteroxy phototransformation was not observed. Finally, for the compound trapped in solid n-D2, the oxo → hydroxy phototautomerism clearly occurred, but the yield of the hydroxy tautomer was small (ca. 18% of the yield in solid Ar). Apart from hydrogen-atom-transfer processes, two other phototransformations: generation of open-ring conjugated ketene and valence Dewar isomer were observed for the compound isolated in Ar, Ne, n-D2, and n-H2 matrices.

  13. Ubiquitous Computing at its best: Serious exercise games for older adults in ambient assisted living environments – a technology acceptance perspective

    Directory of Open Access Journals (Sweden)

    Philipp Brauner

    2015-07-01

    Full Text Available Ubiquitous computing and ambient assisted living environments offer promising solutions to meet the demographic change. An example are serious games for health care: Regular exercises mediated through games increase health, well-being, and autonomy of the residents whilst at the same time reducing the costs for caregiving. To understand which factors contribute to an increased acceptance of such exercise games in ambient assisted living environments, a prototypic game was evaluated with 32 younger and 32 older players. Game performance is influenced by age, need for achievement, and also gender. Acceptance and projected use are related to the believe in making the game a habit, current gaming frequency, and social influences. Notably, the game increased the perceived health of the subjects, which is an important issue. This article concludes with guidelines to successfully introduce serious exercise games into health care and future ideas to realize social inclusion in game design.

  14. Technical basis for the initiation and cessation of environmentally-assisted cracking of low-alloy steels in elevated temperature PWR environments

    Energy Technology Data Exchange (ETDEWEB)

    James, L.A.

    1997-10-01

    The Section 11 Working Group on Flaw Evaluation of the ASME B and PV Code Committee is considering a Code Case to allow the determination of the conditions under which environmentally-assisted cracking of low-alloy steels could occur in PWR primary environments. This paper provides the technical support basis for such an EAC Initiation and Cessation Criterion by reviewing the theoretical and experimental information in support of the proposed Code Case.

  15. Charge-Assisted Hydrogen-Bonded Networks of NH4+ and [Co(NH36]3+ with the New Linker Anion of 4-Phosphono-Biphenyl-4′-Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Christian Heering

    2016-02-01

    Full Text Available The new linker molecule 4-phosphono-biphenyl-4′-carboxylic acid (H2O3P-(C6H42-COOH, H3BPPA has been structurally elucidated in hydrogen-bonded networks with the ammonium cation NH4(H2BPPA(H3BPPA (1 and the hexaamminecobalt(III cation [Co(NH36](BPPA·4H2O (2. The protic O-H and N-H hydrogen atoms were found and refined in the low-temperature single-crystal X-ray structures. The hydrogen bonds in both structures are so-called charge-assisted; that is, the H-bond donor and/or acceptor carry positive and/or negative ionic charges, respectively. The H-bonded network in 1 consists of one formally mono-deprotonated 4-phosphonato-biphenyl-4′-carboxylic acid group; that is, a H2BPPA− anion and a neutral H3BPPA molecule, which together form a 3D hydrogen-bonded network. However, an almost symmetric resonance-assisted hydrogen bond (RAHB bond [O···H = 1.17 (3 and 1.26 (3 Å, O···H···O = 180 (3°] signals charge delocalization between the formal H2BPPA− anion and the formally neutral H3BPPA molecule. Hence, the anion in 1 is better formulated as [H2BPPA···H···H2BPPA]−. In the H-bonded network of 2 the 4-phosphonato-biphenyl-4′-carboxylic acid is triply deprotonated, BPPA3−. The [Co(NH36]3+ cation is embedded between H-bond acceptor groups, –COO− and –PO3− and H2O molecules. The incorporation of sixteen H2O molecules per unit cell makes 2 an analogue of the well-studied guanidinium sulfonate frameworks.

  16. Hydrogen assisted biological biogas upgrading

    DEFF Research Database (Denmark)

    Bassani, Ilaria

    , produced by water electrolysis, using excess of electricity from wind mills, is coupled with the CO2 contained in the biogas to convert them to CH4. This process is defined as biological biogas upgrading and is carried out by hydrogenotrophic methanogenic archaea that couples CO2 with H2 to produce...... of several recurrent microbial groups, including resilient methanogenic archaea such as Methanoculleus and Methanotermobacter and bacteria belonging to phylum Proteobacteria and genus Synthrophomonas. Moreover, upon H2 addition, the concomitant proliferation of hydrogenotrophic methanogens and syntrophic...... bacteria, such as Desulfovibrio, and some Thermoanaerobacteraceae and Syntrophomonadaceae, and the reduction of aceticlastic methanogens and fermentative bacteria state the role of the H2 moving biomethanation process toward the final steps stimulating CO2 consumption and therefore biogas upgrading....

  17. Hydrogen diffusion into fatigue cracks of aluminium alloy 6013 in a corrosive environment; Wasserstoffeinlagerung an Ermuedungsrissen der Aluminiumlegierung 6013 unter korrosiver Umgebung

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, Christian Alexander

    2009-08-13

    The author attempted a time-resolved detection of raised hydrogen concentrations in the plastic deformation region of fatigue cracks in an aluminium test piece deformed by cyclic stress in a corrosive environment. Mechanical material parameters like the crack propagation velocity under cyclic stress change dramatically in a corrosive environment. This is assumed to be caused by hydrogen diffusion, but so far there is no method that reliably measures additional hydrogen from the corrosive environment. For this reason, a special analytical configuration was set up which makes use of the thermal desorption method. First, chips with a thickness of about 20 micrometers are sawed out of the test specimen in high-vacuum conditions. The chips fall into a hot melting vessel in a UHV chamber, where the hydrogen contained in the chips is released. The resulting pressure increase is recorded by a mass spectrometer. A hydrogen profile of the test specimen is obtained by assigning the chip position to the signal. For the corrosive medium in which the test specimen is immersed during crack initiation, i.e. NaCl solution, heavy water was used. This makes it possible to distinguish between the hydrogen contained in a piece of technical aluminium alloy (AA6013) and the deuterium diffusing in from the corrosive fluid. The deuterium is found exclusively in the test piece volume in the strongly plastically deformed region surrounding the fatigue crack. (orig.) [German] Das Ziel der vorliegenden Arbeit besteht im ortsaufgeloesten Nachweis einer erhoehten Wasserstoffkonzentration im plastisch deformierten Bereich von Ermuedungsrissen einer unter korrosiver Umgebung zyklisch verformten Aluminiumprobe. Mechanische Materialparameter wie z.B. die Rissausbreitungsgeschwindigkeit unter zyklischer Belastung aendern sich drastisch in korrosiver Umgebung. Als Ursache fuer dieses Verhalten wird eine Eindiffusion von Wasserstoff vermutet, jedoch gibt es bisher keine Messung die den zusaetzlichen

  18. Intelligent Temporal Data Driven World Actuation in Ambient Environments Case Study: Anomaly Recognition and Assistance Provision in Smart Home

    Data.gov (United States)

    National Aeronautics and Space Administration — Abstract — A possible resident of smart home is an old person or an Alzheimer patient that should be assisted continuously for the rest of his life; however,...

  19. Structural characteristics of copper/hydrogenated amorphous carbon composite films prepared by microwave plasma-assisted deposition processes from methane-argon and acetylene-argon gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Thiery, F.; Pauleau, Y.; Grob, J.J.; Babonneau, D

    2004-11-01

    Copper/hydrogenated amorphous carbon (Cu/a-C:H) composite films have been deposited on silicon substrates by a hybrid technique combining microwave plasma-assisted chemical vapor deposition and sputter-deposition from methane-argon and acetylene-argon gas mixtures. The major objective of this work was to investigate the effect of the carbon gas precursor on the structural characteristics of Cu/a-C:H composite films deposited at ambient temperature. The major characteristics of CH{sub 4}-argon and C{sub 2}H{sub 2}-argon plasmas were analyzed by Langmuir probe measurements. The composition of films was determined by Rutherford backscattering spectroscopy, energy recoil detection analyses and nuclear reaction analyses. The carbon content in the films was observed to vary in the range 20-77 at.% and 7.5-99 at.% as the CH{sub 4} and C{sub 2}H{sub 2} concentrations in the gas phase increased from 10 to 100%, respectively. The atom number ratio H/C in the films was scattered approximately 0.4 whatever the carbon gas precursor used. The crystallographic structure and the size of copper crystallites incorporated in the a-C were determined by X-ray diffraction techniques. The copper crystallite size decreased from 20 nm in pure copper films to less than 5 nm in Cu/a-C:H films containing more than 40 at.% of carbon. Grazing incidence small angle X-ray scattering measurements were performed to investigate the size distribution and distance of copper crystallites as functions of the deposition parameters. The structural characteristics of copper crystallites were dependent on the hydrocarbon gas precursor used. The crystallite size and the width of the size distribution were homogeneous in films deposited from CH{sub 4}. Copper crystallites with an anisotropic shape were found in films deposited from C{sub 2}H{sub 2}. The major radicals formed in the plasma and condensed on the surface of growing films, namely CH and C{sub 2}H radicals for films produced from CH{sub 4} and C

  20. Atomic scale fabrication of dangling bond structures on hydrogen passivated Si(0 0 1) wafers processed and nanopackaged in a clean room environment

    Science.gov (United States)

    Kolmer, Marek; Godlewski, Szymon; Zuzak, Rafal; Wojtaszek, Mateusz; Rauer, Caroline; Thuaire, Aurélie; Hartmann, Jean-Michel; Moriceau, Hubert; Joachim, Christian; Szymonski, Marek

    2014-01-01

    Specific surfaces allowing the ultra-high vacuum (UHV) creation of electronic interconnects and atomic nanostructures are required for the successful development of novel nanoscale electronic devices. Atomically flat and reconstructed Si(0 0 1):H surfaces are serious candidates for that role. In this work such Si:H surfaces were prepared in a cleanroom environment on 200 mm silicon wafers with a hydrogen bake and were subsequently bonded together to ensure the surface protection, and allow their transportation and storage for several months in air. Given the nature of the bonding, which was hydrophobic with weak van der Waals forces, we were then able to de-bond them in UHV. We show that the quality of the de-bonded Si:H surface enables the "at will" construction of sophisticated and complex dangling bond (DB) nanostructures by atomically precise scanning tunneling microscope (STM) tip induced desorption of hydrogen atoms. The DB structures created on slightly doped Si:H samples were characterized by scanning tunneling microscopy and spectroscopy (STM/STS) performed at 4 K. Our results demonstrate that DB nanostructures fabricated on UHV de-bonded Si(0 0 1):H wafers could be directly incorporated in future electronics as interconnects and parts of nanoscale logic circuits.

  1. Atomic scale fabrication of dangling bond structures on hydrogen passivated Si(0 0 1) wafers processed and nanopackaged in a clean room environment

    Energy Technology Data Exchange (ETDEWEB)

    Kolmer, Marek; Godlewski, Szymon; Zuzak, Rafal; Wojtaszek, Mateusz [Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Reymonta Str. 4, PL 30-059 Krakow (Poland); Rauer, Caroline; Thuaire, Aurélie; Hartmann, Jean-Michel; Moriceau, Hubert [CEA, LETI, Minatec Campus, 17, Avenue des Martyrs, 38 054 Grenoble Cedex 9 (France); Joachim, Christian [Nanosciences Group and MANA Satellite, CEMES-CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse (France); Szymonski, Marek, E-mail: marek.szymonski@uj.edu.pl [Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Reymonta Str. 4, PL 30-059 Krakow (Poland)

    2014-01-01

    Specific surfaces allowing the ultra-high vacuum (UHV) creation of electronic interconnects and atomic nanostructures are required for the successful development of novel nanoscale electronic devices. Atomically flat and reconstructed Si(0 0 1):H surfaces are serious candidates for that role. In this work such Si:H surfaces were prepared in a cleanroom environment on 200 mm silicon wafers with a hydrogen bake and were subsequently bonded together to ensure the surface protection, and allow their transportation and storage for several months in air. Given the nature of the bonding, which was hydrophobic with weak van der Waals forces, we were then able to de-bond them in UHV. We show that the quality of the de-bonded Si:H surface enables the “at will” construction of sophisticated and complex dangling bond (DB) nanostructures by atomically precise scanning tunneling microscope (STM) tip induced desorption of hydrogen atoms. The DB structures created on slightly doped Si:H samples were characterized by scanning tunneling microscopy and spectroscopy (STM/STS) performed at 4 K. Our results demonstrate that DB nanostructures fabricated on UHV de-bonded Si(0 0 1):H wafers could be directly incorporated in future electronics as interconnects and parts of nanoscale logic circuits.

  2. Early establishment response of different Pinus nigra ssp. salzmanii seed sources on contrasting environments: Implications for future reforestation programs and assisted population migration.

    Science.gov (United States)

    Taïbi, K; del Campo, A D; Aguado, A; Mulet, J M

    2016-04-15

    Forest restoration constitutes an important issue within adaptive environmental management for climate change at global scale. However, effective implementation of these programs can only be achieved by revising current seed transfer guidelines, as they lack inherent spatial and temporal dynamics associated with climate change. In this sense, provenance trials may provide key information on the relative performance of different populations and/or genotypes under changing ecological conditions. This study addresses a methodological approach to evaluate early plantation performance and the consequent phenotypic plasticity and the pattern of the adaptation of different seed sources in contrasting environments. To this end, six seed sources of Salzmann pine were tested at three contrasting trial sites testing a hypothetical assisted population migration. Adaptation at each site was assessed through Joint Regression and Additive Main effect and Multiplication Interaction (AMMI) models. Most of the observed variation was attributed to the environment (above 90% for all traits), even so genotype and genotype by environment interaction (GxE) were significant. Seedlings out-planted under better site conditions did not differ in survival but in height growth. However, on sites with higher constraints, survival differed among seed sources and diameter growth was high. The adaptation analyses (AMMI) indicated that the cold-continental seed source 'Soria' performed as a generalist seed source, whereas 'Cordilleras Béticas', the southernmost seed source, was more adapted to harsh environments (frost and drought) in terms of survival. The results supported partially the hypothesis that assisted migration of seed sources makes sense within limited transfer distances, and this was reinforced by the GxE results. The present study could be valuable to address adaptive transfer of seedings in ecological restoration and to determine the suitable seed sources for reforestation programs

  3. Significantly Dense Two-Dimensional Hydrogen-Bond Network in a Layered Zirconium Phosphate Leading to High Proton Conductivities in Both Water-Assisted Low-Temperature and Anhydrous Intermediate-Temperature Regions.

    Science.gov (United States)

    Gui, Daxiang; Zheng, Tao; Xie, Jian; Cai, Yawen; Wang, Yaxing; Chen, Lanhua; Diwu, Juan; Chai, Zhifang; Wang, Shuao

    2016-12-19

    A highly stable layered zirconium phosphate, (NH4)2[ZrF2(HPO4)2] (ZrP-1), was synthesized by an ionothermal method and contains an extremely dense two-dimensional hydrogen-bond network that is thermally stable up to 573 K, leading to combined ultrahigh water-assisted proton conductivities of 1.45 × 10(-2) S cm(-1) at 363 K/95% relative humidity and sustainable anhydrous proton conductivity of 1.1 × 10(-5) S cm(-1) at 503 K.

  4. Marker-assisted assessment of genotype by environment interaction: a case study of single nucleotide polymorphism-mortality association in broilers in two hygiene environments.

    Science.gov (United States)

    Long, N; Gianola, D; Rosa, G J M; Weigel, K A; Avendaño, S

    2008-12-01

    Interplay between genetic and environmental factors, genotype x environment interactions (G x E), affect phenotypes of complex traits. A methodology for assessing G x E was investigated by detecting hygiene (low and high) environment-specific SNP subsets associated with broiler chicken mortality, followed by an examination of consistency between SNP subsets selected from the 2 environments. The trait was mean progeny mortality rate in 253 sire families, after adjusting records for nuisance effects affecting mortality at the individual bird level. Over 5,000 whole-genome SNP were narrowed down via a machine-learning (filter-wrapper) feature selection procedure applied to mortality rates in each of the 2 environments. For both early and late mortality, it was found that the selected SNP subsets differed across hygiene environments, in terms of either across-environment predictive ability or extent of linkage disequilibrium between the subsets. Reduction in predictive ability due to G x E was assessed by the ratio of 2 predicted residual sum of squares statistics, one associated with SNP selected from the same hygiene environment and the other associated with the SNP subset from a different environment. Reduction was 30 and 20% for early and late mortality, respectively. An extremely low level of linkage disequilibrium between SNP subsets selected under low and high hygiene also indicated G x E. Findings suggest that there may not be a universally optimal SNP subset for predicting mortality and that interactions between genome and environmental factors need to be considered in association analysis of complex traits.

  5. How Artefacts Mediate Small-Group Co-Creation Activities in a Mobile-Assisted Seamless Language Learning Environment?

    Science.gov (United States)

    Wong, L. -H.; Chen, W.; Jan, M.

    2012-01-01

    The rich learning resources and contexts learners experience in their everyday life could play important roles in complementing formal learning, but are often neglected by learners and teachers. In this paper, we present an intervention study in "Move, Idioms!", a mobile-assisted Chinese language learning approach that emphasizes contextualized…

  6. Studies on membrane acid electrolysis for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marco Antonio Oliveira da; Linardi, Marcelo; Saliba-Silva, Adonis Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Celulas a Combustivel e Hidrogenio], Email: saliba@ipen.br

    2010-07-01

    Hydrogen represents great opportunity to be a substitute for fossil fuels in the future. Water as a renewable source of hydrogen is of great interest, since it is abundant and can decompose, producing only pure H{sub 2} and O{sub 2}. This decomposition of water can be accomplished by processes such as electrolysis, thermal decomposition and thermochemical cycles. The electrolysis by membrane has been proposed as a viable process for hydrogen production using thermal and electrical energy derived from nuclear energy or any renewable source like solar energy. In this work, within the context of optimization of the electrolysis process, it is intended to develop a mathematical model that can simulate and assist in parameterization of the electrolysis performed by polymer membrane electrolytic cell. The experimental process to produce hydrogen via the cell membrane, aims to optimize the amount of gas produced using renewable energy with noncarbogenic causing no harm by producing gases deleterious to the environment. (author)

  7. Pacific Northwest Laboratory annual report for 1979 to the DOE Assistant Secretary for Environment. Part 5. Environmental assessment, control, health, and safety

    Energy Technology Data Exchange (ETDEWEB)

    Baalman, R.W.; Dotson, C.W. (eds.)

    1980-02-01

    Part 5 of the 1979 Annual Report to the Department of Energy Assistant Secretary for the Environment presents Pacific Northwest Laboratory's progress on work performed for the Office of Technology Impacts, the Office of Environmental Compliance and Overview, and the Office of Health and Environmental Research. The report is in four sections, corresponding to the program elements: technology impacts, environmental control engineering, operational and environmental compliance, and human health studies. In each section, articles describe progress made during FY 1979 on individual projects.

  8. Stress Corrosion Analysis and Control for Equipment in Wet Sulfide Hydrogen Environment%湿硫化氢环境中设备应力腐蚀分析及控制

    Institute of Scientific and Technical Information of China (English)

    邵昀启

    2012-01-01

      文章阐述了硫化氢应力腐蚀机理,分析和探讨了在湿硫化氢环境中影响应力腐蚀的相关因素,并针对这些影响因素提出了相应的防止硫化氢应力腐蚀的技术和工艺措施。%  The article discusses the mechanism of sulfide hydrogen stress corrosion, analysis and discussion of the influencing factors of sulfide hydrogen stress corrosion in wet sulfide hydrogen environment, and in view of these factors put forward a number of technology and process measures to prevent sulfide hydrogen stress corrosion.

  9. Pacific Northwest Laboratory annual report for 1980 to the DOE Assistant Secretary for Environment. Part 5. Environmental assessment, control, health and safety

    Energy Technology Data Exchange (ETDEWEB)

    Baalman, R.W.; Hays, I.D. (eds.)

    1981-02-01

    Pacific Northwest Laboratory's (PNL) 1980 annual report to the DOE Assistant Secretary for Environment describes research in environment, health, and safety conducted during fiscal year 1980. Part 5 includes technology assessments for natural gas, enhanced oil recovery, oil shale, uranium mining, magnetic fusion energy, solar energy, uranium enrichment and industrial energy utilization; regional analysis studies of environmental transport and community impacts; environmental and safety engineering for LNG, oil spills, LPG, shale oil waste waters, geothermal liquid waste disposal, compressed air energy storage, and nuclear/fusion fuel cycles; operational and environmental safety studies of decommissioning, environmental monitoring, personnel dosimetry, and analysis of criticality safety; health physics studies; and epidemiological studies. Also included are an author index, organization of PNL charts and distribution lists of the annual report, along with lists of presentations and publications. (DLS)

  10. Modeling of Plasma-Assisted Conversion of Liquid Ethanol into Hydrogen Enriched Syngas in the Nonequilibrium Electric Discharge Plasma-Liquid System

    CERN Document Server

    Levko, Dmitry; Naumov, Vadim; Chernyak, Valery; Yukhymenko, Vitaly; Prysiazhnevych, Irina; Olszewski, Sergey

    2008-01-01

    In this work we report recent results of our experimental and theoretical studies related to plasma conversion of liquid ethanol into hydrogen-enriched syngas in the plasma-liquid system with the electric discharge in a gas channel with liquid wall using available diagnostics and numerical modeling.

  11. Computer assisted dynamic adaptive policy design for sustainable water management in river deltas in a changing environment

    NARCIS (Netherlands)

    Kwakkel, J.H.; Haasnoot, M.

    2012-01-01

    Sustainable water management in a changing environment full of uncertainty is a profound challenge. To deal with uncertainties, dynamic adaptive policies can be used. Such policies can change over time in response to how the future unfolds, to what we learn about the system, to changes in environmen

  12. Fostering Self-Regulated Learning in a Blended Environment Using Group Awareness and Peer Assistance as External Scaffolds

    Science.gov (United States)

    Lin, J-W.; Lai, Y-C.; Lai, Y-C.; Chang, L-C.

    2016-01-01

    Most systems for training self-regulated learning (SRL) behaviour focus on the provision of a learner-centred environment. Such systems repeat the training process and place learners alone to experience that process iteratively. According to the relevant literature, external scaffolds are more promising for effective SRL training. In this work,…

  13. Early retirement among Danish female cleaners and shop assistants according to work environment characteristics and upper extremity complaints

    DEFF Research Database (Denmark)

    Jensen, Lone Donbæk; Bonde, Jens Peter Ellekilde; Christensen, Michael Victor

    2016-01-01

    -year cohort study with registry-based follow-up of 1430 female cleaners and 579 shop assistants. In subsequent analyses of female cleaners, disability pension and voluntary early retirement were modeled according to work characteristics and upper extremity complaints. RESULTS: The adjusted hazard rate......BACKGROUND: Studies have shown a negative social gradient in the incidence of early retirement. To prevent undesired early retirement, there is a need for knowledge of specific predictors in addition to social factors with a limited potential for change. The main purpose of this study...... was to examine musculoskeletal complaints and working conditions as predictors of early retirement among Danish female cleaners. METHODS: Using Cox regression with an adjustment for extraneous factors, we compared the risk of disability pension and retirement before the nominal retirement age (65 years) in an 11...

  14. Distributed Denial of Service Attack Source Detection Using Efficient Traceback Technique (ETT) in Cloud-Assisted Healthcare Environment.

    Science.gov (United States)

    Latif, Rabia; Abbas, Haider; Latif, Seemab; Masood, Ashraf

    2016-07-01

    Security and privacy are the first and foremost concerns that should be given special attention when dealing with Wireless Body Area Networks (WBANs). As WBAN sensors operate in an unattended environment and carry critical patient health information, Distributed Denial of Service (DDoS) attack is one of the major attacks in WBAN environment that not only exhausts the available resources but also influence the reliability of information being transmitted. This research work is an extension of our previous work in which a machine learning based attack detection algorithm is proposed to detect DDoS attack in WBAN environment. However, in order to avoid complexity, no consideration was given to the traceback mechanism. During traceback, the challenge lies in reconstructing the attack path leading to identify the attack source. Among existing traceback techniques, Probabilistic Packet Marking (PPM) approach is the most commonly used technique in conventional IP- based networks. However, since marking probability assignment has significant effect on both the convergence time and performance of a scheme, it is not directly applicable in WBAN environment due to high convergence time and overhead on intermediate nodes. Therefore, in this paper we have proposed a new scheme called Efficient Traceback Technique (ETT) based on Dynamic Probability Packet Marking (DPPM) approach and uses MAC header in place of IP header. Instead of using fixed marking probability, the proposed scheme uses variable marking probability based on the number of hops travelled by a packet to reach the target node. Finally, path reconstruction algorithms are proposed to traceback an attacker. Evaluation and simulation results indicate that the proposed solution outperforms fixed PPM in terms of convergence time and computational overhead on nodes.

  15. Development of an audio-based virtual gaming environment to assist with navigation skills in the blind.

    Science.gov (United States)

    Connors, Erin C; Yazzolino, Lindsay A; Sánchez, Jaime; Merabet, Lotfi B

    2013-03-27

    Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind. Using only audio based cues and set within the context of a video game metaphor, users gather relevant spatial information regarding a building's layout. This allows the user to develop an accurate spatial cognitive map of a large-scale three-dimensional space that can be manipulated for the purposes of a real indoor navigation task. After game play, participants are then assessed on their ability to navigate within the target physical building represented in the game. Preliminary results suggest that early blind users were able to acquire relevant information regarding the spatial layout of a previously unfamiliar building as indexed by their performance on a series of navigation tasks. These tasks included path finding through the virtual and physical building, as well as a series of drop off tasks. We find that the immersive and highly interactive nature of the AbES software appears to greatly engage the blind user to actively explore the virtual environment. Applications of this approach may extend to larger populations of visually impaired individuals.

  16. Hydrogen Embrittlement of Structural Steels

    Energy Technology Data Exchange (ETDEWEB)

    Somerday, Brian P.; San Marchi, Christopher W

    2014-08-01

    Carbon-manganese steels are candidates for the structural materials in hydrogen gas pipelines; however, it is well known that these steels are susceptible to hydrogen embrittlement. Decades of research and industrial experience have established that hydrogen embrittlement compromises the structural integrity of steel components. This experience has also helped identify the failure modes that can operate in hydrogen containment structures. As a result, there are tangible ideas for managing hydrogen embrittlement in steels and quantifying safety margins for steel hydrogen containment structures. For example, fatigue crack growth aided by hydrogen embrittlement is a well-established failure mode for steel hydrogen containment structures subjected to pressure cycling. This pressure cycling represents one of the key differences in operating conditions between current hydrogen pipelines and those anticipated in a hydrogen delivery infrastructure. Applying structural integrity models in design codes coupled with measurement of relevant material properties allows quantification of the reliability/integrity of steel hydrogen pipelines subjected to pressure cycling. Furthermore, application of these structural integrity models is aided by the development of physics-based predictive models, which provide important insights such as the effects of microstructure on hydrogen-assisted fatigue crack growth. Successful implementation of these structural integrity and physics-based models enhances confidence in the design codes and enables decisions about materials selection and operating conditions for reliable and efficient steel hydrogen pipelines.

  17. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  18. Pacific Northwest Laboratory annual report for 1979 to the DOE Assistant Secretary for Environment. Part 2. Ecological sciences

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, B.E.

    1980-02-01

    Research in Environment, Health, and Safety conducted during fiscal year 1979 is reported. This volume consists of project reports from the Ecological Sciences research department. The reports are grouped under the following subject areas: National Environmental Research Park and land use; Alaskan resource research; shale oil; synfuels; nuclear waste; fission; marine research programs; statistical development of field research; nuclear fusion; pumped storage and hydroelectric development; pathways modelling, assessment and Hanford project support; electric field and microwave research; and energy research for other agencies. (ACR)

  19. More Than Just a Break from Treatment: How Substance Use Disorder Patients Experience the Stable Environment in Horse-Assisted Therapy

    Science.gov (United States)

    Kern-Godal, Ann; Brenna, Ida Halvorsen; Arnevik, Espen Ajo; Ravndal, Edle

    2016-01-01

    Inclusion of horse-assisted therapy (HAT) in substance use disorder (SUD) treatment is rarely reported. Our previous studies show improved treatment retention and the importance of the patient–horse relationship. This qualitative study used thematic analysis, within a social constructionist framework, to explore how eight patients experienced contextual aspects of HAT’s contribution to their SUD treatment. Participants described HAT as a “break from usual treatment”. However, four interrelated aspects of this experience, namely “change of focus”, “activity”, “identity”, and “motivation,” suggest HAT is more than just a break from usual SUD treatment. The stable environment is portrayed as a context where participants could construct a positive self: one which is useful, responsible, and accepted; more fundamentally, a different self from the “patient/self” receiving treatment for a problem. The implications extend well beyond animal-assisted or other adjunct therapies. Their relevance to broader SUD policy and treatment practices warrants further study.

  20. Nanochemistry in confined environments: polyelectrolyte brush-assisted synthesis of gold nanoparticles inside ordered mesoporous thin films.

    Science.gov (United States)

    Calvo, Alejandra; Fuertes, M Cecilia; Yameen, Basit; Williams, Federico J; Azzaroni, Omar; Soler-Illia, Galo J A A

    2010-04-20

    A robust and straightforward strategy allowing the controlled confinement of metal nanoparticles within the 3D framework of mesoporous films is presented. The chemical methodology is based on the inner surface modification of mesoporous silica films with polyelectrolyte brushes. We demonstrate that the macromolecular building blocks significantly enhance the site-selective preconcentration of nanoparticle precursors in the inner environment of the mesoporous film. Then, chemical reduction of the preconcentrated precursors led to the formation of metal nanoparticles locally addressed in the mesoporous structure. We show that the synergy taking place between two versatile functional nanobuilding blocks (ordered mesocavities and polymer brushes) can produce stable embedded nanoparticles with tuned optical properties in a very simple manner. As a general framework, the strategy can be easily adapted to different sets of polymer brushes and mesoporous films in order to regulate the monomer-precursor interactions and, consequently, manipulate the site-selective character of the different chemistries taking place in the film. We consider that the "integrative chemistry" approach described in this work provides new pathways to manipulate the physicochemical characteristics of hybrid organic-inorganic advanced functional assemblies based on the rational design of chemistry and topology in confined environments.

  1. Concept of an immersive assistance system with augmented reality for the support of manual activities in radioactive production environments; Konzept eines immersiven Assistenzsystems mit Augmented Reality zur Unterstuetzung manueller Aktivitaeten in radioaktiven Produktionsumgebungen

    Energy Technology Data Exchange (ETDEWEB)

    Eursch, Andreas A.

    2010-06-29

    The thesis on an immersive assistance system concept with augmented reality for the support of manual activities in radioactive production environments covers the following topics: analysis of the situation: production and use of radioactive materials, problem analysis of the work in the production facilities, necessity of manual activities, automation, prediction in hot cells; status of research and development; assistance system concept, immersive camera system; augmented reality support in hot cells; economic evaluation and generalization.

  2. Hydrogen induced plastic deformation of stainless steel

    NARCIS (Netherlands)

    Gadgil, V.J.; Keim, Enrico G.; Geijselaers, Hubertus J.M.

    1998-01-01

    Hydrogen can influence the behaviour of materials significantly. The effects of hydrogen are specially pronounced in high fugacities of hydrogen which can occur at the surface of steels in contact with certain aqueous environments. In this investigation the effect of high fugacity hydrogen on the

  3. Pressure-assisted cold denaturation of hen egg white lysozyme: the influence of co-solvents probed by hydrogen exchange nuclear magnetic resonance

    Directory of Open Access Journals (Sweden)

    Vogtt K.

    2005-01-01

    Full Text Available COSY proton nuclear magnetic resonance was used to measure the exchange rates of amide protons of hen egg white lysozyme (HEWL in the pressure-assisted cold-denatured state and in the heat-denatured state. After dissolving lysozyme in deuterium oxide buffer, labile protons exchange for deuterons in such a way that exposed protons are substituted rapidly, whereas "protected" protons within structured parts of the protein are substituted slowly. The exchange rates k obs were determined for HEWL under heat treatment (80ºC and under high pressure conditions at low temperature (3.75 kbar, -13ºC. Moreover, the influence of co-solvents (sorbitol, urea on the exchange rate was examined under pressure-assisted cold denaturation conditions, and the corresponding protection factors, P, were determined. The exchange kinetics upon heat treatment was found to be a two-step process with initial slow exchange followed by a fast one, showing residual protection in the slow-exchange state and P-factors in the random-coil-like range for the final temperature-denatured state. Addition of sorbitol (500 mM led to an increase of P-factors for the pressure-assisted cold denatured state, but not for the heat-denatured state. The presence of 2 M urea resulted in a drastic decrease of the P-factors of the pressure-assisted cold denatured state. For both types of co-solvents, the effect they exert appears to be cooperative, i.e., no particular regions within the protein can be identified with significantly diverse changes of P-factors.

  4. Estuarine refugia and fish responses to a large anoxic, hydrogen sulphide, “black tide” event in the adjacent marine environment

    Science.gov (United States)

    Lamberth, S. J.; Branch, G. M.; Clark, B. M.

    2010-01-01

    The fish fauna of the Berg River Estuary was sampled from the mouth to 40 km upstream using a small-meshed seine-net before (summer 1993), during (summer 1994) and after (summer 1996) a low-oxygen, hydrogen sulphide "black tide" event that caused a mass mortality of fish in St Helena Bay. These data were compared to determine how the species composition, abundance and distribution of the fish fauna of the Berg River Estuary differed before, during and after the event as well as to ascertain which species, if any, found refuge in the estuary. The overall catch-per-unit-effort of 1637 fish.haul -1 during the event was almost double the 932 fish.haul -1 and 643 fish.haul -1 in the years before and after respectively. All the fish recorded alive in the estuary during the event were species known to have some degree of estuarine association. No representatives of the purely marine species found dead on the adjacent shoreline were recorded live in the estuary during the event. Of the 10 estuarine-associated species sampled, 5 extended their range and/or modal peaks of abundance further upstream during the event. One species, Liza richardsonii, was abundant enough to examine its size distribution in different breaches of the estuary. Large/adult fish were concentrated further upstream than small/juvenile fish, which appeared to be unable to escape tidal currents and were concentrated at the edge of the low-oxygen front. Collectively this circumstantial evidence indicates that (1) fish used the Berg Estuary as a refuge from low-oxygen conditions in the marine environment during the "black tide" event, and (2) the ability to secure refuge in the estuary was restricted to species described as "estuarine-associated" or "estuarine-dependent".

  5. Mercaptosilane-assisted synthesis of sub-nanosized Pt particles within hierarchically porous ZSM-5/SBA-15 materials and their enhanced hydrogenation properties

    Science.gov (United States)

    Gao, Daowei; Zheng, Anmin; Zhang, Xin; Sun, Hui; Dai, Xiaoping; Yang, Ying; Wang, Hai; Qin, Yuchen; Xu, Shutao; Duan, Aijun

    2015-06-01

    A novel catalyst that consists of sub-nanosized Pt particles within hierarchically porous ZSM-5/SBA-15 materials was synthesized. This catalyst exhibited high stability and a hierarchically porous structure of a micro-mesoporous composite and possessed a high density of active sites by confinement of sub-nanosized Pt particles within small-pore zeolites, showing high catalytic properties for the hydrogenation of 1,3-butadiene and cyclooctadiene at room temperature.A novel catalyst that consists of sub-nanosized Pt particles within hierarchically porous ZSM-5/SBA-15 materials was synthesized. This catalyst exhibited high stability and a hierarchically porous structure of a micro-mesoporous composite and possessed a high density of active sites by confinement of sub-nanosized Pt particles within small-pore zeolites, showing high catalytic properties for the hydrogenation of 1,3-butadiene and cyclooctadiene at room temperature. Electronic supplementary information (ESI) available: Experimental details, characterization, reaction data. See DOI: 10.1039/c5nr02749g

  6. Morphology Evolution of (331)A High-Index Surfaces During Atomic Hydrogen Assisted Molecular Beam Epitaxy (MBE)%原子氢辅助分子束外延GaAs(331)A表面形貌演化

    Institute of Scientific and Technical Information of China (English)

    牛智红; 任正伟; 贺振宏

    2008-01-01

    Step like morphology of (331)A high-index surfaces during atomic hydrogen assisted molecular beam epitaxy (MBE) growth has been investigated. Atomic Force Microscope (AFM) measurements show that in conventional MBE, the step heights and terrace widths of GaAs layers increase monotonically with increasing substrate temperatures. The terrace widths and step densities increase with increasing the GaAs layer thickness and then saturates. And, in atomic hydrogen assisted MBE, the terrace width reduces and density increases when depositing the same amount of GaAs. It attributes this to the reduced surface migration length of Ga adatoms with atomic hydrogen. Laterally ordered InAs self-aligned nano-wires were grown on GaAs (331)A surfaces and its optical polarization properties were revealed by photoluminescence measurements.%研究了GaAs高指数面(331)A在原子氢辅助下分子束外延形貌的演化.原子力显微镜测试表明:在常规分子束外延情况下,GaAs外延层台阶的厚度和台面的宽度随衬底温度的升高而增加,增加外延层厚度会导致台阶的密度和台面的宽度增加然后饱和.而在原子氢辅助分子束外延情况下,当GaAs淀积量相同时GaAs外延层台阶的密度增大宽度减小.认为这是由于原子氢的作用导致Ga原子迁移长度的减小.在GaAs(331)A台阶基底上生长出InAs自组织纳米线,用光荧光测试研究了其光学各项异性特征.

  7. Effects of the use of assisted reproductive technologies and an obesogenic environment on resistance artery function and diabetes biomarkers in mice offspring.

    Directory of Open Access Journals (Sweden)

    Francisco I Ramirez-Perez

    Full Text Available Maternal obesity affects the incidence of cardiovascular disease and diabetes in offspring. Also the use of assisted reproductive technologies (ART has been associated with cardiovascular deficiencies in offspring. Obese women often suffer from infertility and use ART to achieve a pregnancy, but the combined effects of maternal obesity and ART on cardiovascular health and incidence of diabetes in the offspring is not known. Here, we report the effects of the use of ART within an obesogenic environment, consisting of feeding a western diet (WD to dams and offspring, on resistance artery function and presence of diabetes biomarkers in juvenile mice offspring. Our results indicate that WD and ART interacted to induce endothelial dysfunction in mesenteric resistance arteries isolated from 7-week-old mice offspring. This was determined by presence of a reduced acetylcholine-induced dilation compared to controls. The arteries from these WD-ART mice also had greater wall cross-sectional areas and wall to lumen ratios indicative of vascular hypertrophic remodeling. Of the diabetes biomarkers measured, only resistin was affected by a WD×ART interaction. Serum resistin was significantly greater in WD-ART offspring compared to controls. Diet and sex effects were observed in other diabetes biomarkers. Our conclusion is that in mice the use of ART within an obesogenic environment interacts to favor the development of endothelial dysfunction in the resistance arteries of juvenile offspring, while having marginal effects on diabetes biomarkers.

  8. The unhealthy food environment does not modify the association between obesity and participation in the Supplemental Nutrition Assistance Program (SNAP) in Los Angeles County.

    Science.gov (United States)

    Chaparro, M Pia; Harrison, Gail G; Wang, May C; Seto, Edmund Y W; Pebley, Anne R

    2017-01-14

    Participation in the Supplemental Nutrition Assistance Program (SNAP) has been linked to an increased risk of obesity, but not much is known about the mechanisms behind this association. The objective of this study was to determine if the neighborhood density of unhealthy food outlets modifies the association between obesity and participation in SNAP. Data comes from the first wave of the Los Angeles Family and Neighborhood Survey; included are a subsample of adults (18+ years) who were SNAP participants or eligible non-participants (N = 1,176). We carried out multilevel analyses with obesity (BMI ≥ 30 Kg/m(2)), SNAP participation, and the neighborhood density of unhealthy food outlets as dependent, independent and modifying variables, respectively, controlling for age, gender, race/ethnicity, marital status, working status, mental health, and neighborhood poverty. SNAP participants had double the odds of obesity compared to eligible non-participants (OR = 2.02; 95%CI = 1.44-2.83). However, the neighborhood density of unhealthy food outlets did not modify this association. SNAP participation was associated with higher odds of obesity in our primarily Hispanic sample in Los Angeles County, with no effect modification found for the unhealthy portion of the food environment. More research is needed with additional food environment measures to confirm our null findings. Additional research is needed to elucidate the mechanisms linking SNAP participation and obesity as they remain unclear.

  9. Perceptron system to assist in decision making and monitoring of quality of software development in Information Technology environments

    Directory of Open Access Journals (Sweden)

    Chau Sen Shia

    2016-07-01

    Full Text Available - Classical methods for software development require high costs and problems of communication between development teams, project risks and delays in the delivery of its services. In this work, the aim is to develop a perceptron model to demonstrate the ability to control, service quality assessment and decision-making in IT (Information Technology. For this, we used perceptron network techniques, standards of service quality measures and risk analysis model of applied projects in software engineering. With the network perceptron model implementation was possible to simulate the application of development in several requests for applications for software, in order to meet the management of schedules in all phases of the life cycle of the projects carried out. The tests with the perceptron model were applied in it environments to meet service requests from various fields. The results and analyses presented in these projects demonstrate that communication between development teams were more consistent. It was also possible to predict with more accuracy the delivery of services, decision making and risk reduction projects.

  10. Effect of water chemistry on environmentally assisted cracking of alloy 600 in simulated primary side PWR environments

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, M. [Studsvik Nuvlear (Sweden); Lidar, P. [GSE Power Systems (Sweden); Engstroem, J. [Ringhals NPP (Sweden); Gott, K. [SKI Sweden (Sweden)

    2002-07-01

    Environmental aspects of crack growth due to intergranular stress corrosion cracking (IGSCC) of Alloy 600 in simulated primary side PWR environments have been studied. The purpose of the study was to quantify the effects of the water chemistry (Li, B and H{sub 2} concentrations, and the pH-value by adding KOH) on the crack growth rate, da/dt. 12.5 mm thick compact tension (CT) specimens were used for testing at a constant maximum stress intensity factor in the range of 26-32 MPa{open_square}m. The crack growth was continuously monitored using a direct current potential drop system. Intergranular crack growth due to IGSCC was dominant in the specimens, although there were also small fractions of transgranular cracking. Multivariate analysis was used on the results from the present work together with results from previous tests on the same material. Temperature and the stress intensity were also included as factors in the analysis. A partial least squares regression was developed and interaction effects between the factors were found to affect the crack growth rate. The Partial Least Square regression predicts the observed crack growth rates reasonably well. (authors)

  11. Including parameterization of the discrete ablation process into a planning and simulation environment for robot-assisted laser osteotomy.

    Science.gov (United States)

    Burgner, Jessica; Kahrs, Lüder Alexander; Raczkowsky, Jörg; Wörn, Heinz

    2009-01-01

    Material processing using laser became a widely used method especially in the scope of industrial automation. The systems are mostly based on a precise model of the laser process and the according parameterization. Beside the industrial use the laser as an instrument to treat human tissue has become an integral part in medicine as well. Human tissue as an inhomogeneous material to process, poses the question of how to determine a model, which reflects the interaction processes with a specific laser.Recently it could be shown that the pulsed CO2 laser is suitable to ablate bony and cartilage tissue. Until now this thermo-mechanical bone ablation is not characterized as a discrete process. In order to plan and simulate the ablation process in the correct level of detail, the parameterization is indispensable. We developed a planning and simulation environment, determined parameters by confocal measurements of bony specimen and use these results to transfer planned cutting trajectories into a pulse sequence and corresponding robot locations.

  12. Florida Hydrogen Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Block, David L

    2013-06-30

    The Florida Hydrogen Initiative (FHI) was a research, development and demonstration hydrogen and fuel cell program. The FHI program objectives were to develop Florida?s hydrogen and fuel cell infrastructure and to assist DOE in its hydrogen and fuel cell activities The FHI program funded 12 RD&D projects as follows: Hydrogen Refueling Infrastructure and Rental Car Strategies -- L. Lines, Rollins College This project analyzes strategies for Florida's early stage adaptation of hydrogen-powered public transportation. In particular, the report investigates urban and statewide network of refueling stations and the feasibility of establishing a hydrogen rental-car fleet based in Orlando. Methanol Fuel Cell Vehicle Charging Station at Florida Atlantic University ? M. Fuchs, EnerFuel, Inc. The project objectives were to design, and demonstrate a 10 kWnet proton exchange membrane fuel cell stationary power plant operating on methanol, to achieve an electrical energy efficiency of 32% and to demonstrate transient response time of less than 3 milliseconds. Assessment of Public Understanding of the Hydrogen Economy Through Science Center Exhibits, J. Newman, Orlando Science Center The project objective was to design and build an interactive Science Center exhibit called: ?H2Now: the Great Hydrogen Xchange?. On-site Reformation of Diesel Fuel for Hydrogen Fueling Station Applications ? A. Raissi, Florida Solar Energy Center This project developed an on-demand forecourt hydrogen production technology by catalytically converting high-sulfur hydrocarbon fuels to an essentially sulfur-free gas. The removal of sulfur from reformate is critical since most catalysts used for the steam reformation have limited sulfur tolerance. Chemochromic Hydrogen Leak Detectors for Safety Monitoring ? N. Mohajeri and N. Muradov, Florida Solar Energy Center This project developed and demonstrated a cost-effective and highly selective chemochromic (visual) hydrogen leak detector for safety

  13. An Entropy-Based Kernel Learning Scheme toward Efficient Data Prediction in Cloud-Assisted Network Environments

    Directory of Open Access Journals (Sweden)

    Xiong Luo

    2016-07-01

    Full Text Available With the recent emergence of wireless sensor networks (WSNs in the cloud computing environment, it is now possible to monitor and gather physical information via lots of sensor nodes to meet the requirements of cloud services. Generally, those sensor nodes collect data and send data to sink node where end-users can query all the information and achieve cloud applications. Currently, one of the main disadvantages in the sensor nodes is that they are with limited physical performance relating to less memory for storage and less source of power. Therefore, in order to avoid such limitation, it is necessary to develop an efficient data prediction method in WSN. To serve this purpose, by reducing the redundant data transmission between sensor nodes and sink node while maintaining the required acceptable errors, this article proposes an entropy-based learning scheme for data prediction through the use of kernel least mean square (KLMS algorithm. The proposed scheme called E-KLMS develops a mechanism to maintain the predicted data synchronous at both sides. Specifically, the kernel-based method is able to adjust the coefficients adaptively in accordance with every input, which will achieve a better performance with smaller prediction errors, while employing information entropy to remove these data which may cause relatively large errors. E-KLMS can effectively solve the tradeoff problem between prediction accuracy and computational efforts while greatly simplifying the training structure compared with some other data prediction approaches. What’s more, the kernel-based method and entropy technique could ensure the prediction effect by both improving the accuracy and reducing errors. Experiments with some real data sets have been carried out to validate the efficiency and effectiveness of E-KLMS learning scheme, and the experiment results show advantages of the our method in prediction accuracy and computational time.

  14. Effect of hydrogen peroxide on Dagang vacuum residue oxidation depolymerization assisted with photo-catalytic%过氧化氢对光催化氧化解聚大港减压渣油的影响

    Institute of Scientific and Technical Information of China (English)

    解恒参; 宗志敏; 陈恒宝; 魏贤勇

    2015-01-01

    应用过氧化氢在光催化辅助下对大港减压渣油进行氧化,并进行气相色谱-质谱( GC/MS)和傅里叶红外光谱( FTIR)分析.结果表明:过氧化氢在大港重质减压残渣的光催化氧化过程中起到重要促进作用,能使重油原样中约占70%的正构烷烃逐渐转化成极性较强、有利于分离的含氧化合物(含量达92.94%);含氧化合物主要包括36.05%的有机羧酸、14.56%的有机酯以及9.05 %的其他链式含氧化合物(醚、酮和酚类产物等) ,杂环类化合物达到21.57 %,其中五元环醚化合物(呋喃类)占到19.12%;长链烃能被解聚而减小碳链单元数量;过氧化氢、催化剂、重油减渣的用量和溶剂种类等因素对过氧化氢的氧化作用都有影响.%The Dagang vacuum residue ( DVR) was oxidized by hydrogen peroxide assisted with photo-catalytic. And the oxida-tion efficiency was analyzed through gas chromatography-mass spectrometry ( GC-MS) and Fourier transform infrared spectrosco-py ( FTIR ) . The results indicate that hydrogen peroxide plays an important role of promoting the photo-catalytic oxidation process. And about 70% of the alkane in DVR is gradually converted into some strong polar and easily separated oxygenated compounds, and its relative content reaches 92. 94% in DVR. The compounds mainly include 36. 05% organic carboxylic acids, 14. 56% organic esters, and 9. 05% other chain oxygenated compounds ( ether, ketone, and phenol products etc. ) . The heterocyclic compounds reaches 21. 57%, of which five-membered cyclic ether compounds ( furan) accounts for 19. 12%. And the long chain hydrocarbons can be depolymerized through reduced carbon chain unit number. And the amounts of hydrogen peroxide, catalyst and heavy oil, as well as the different solvents have all influences on hydrogen peroxide oxidation.

  15. Cluster-assisted generation of multi-charged ions in nanosecond laser ionization of pulsed hydrogen sulfide beam at 1064 and 532 nm

    Institute of Scientific and Technical Information of China (English)

    Niu Dong-Mei; Li Hai-Yang; Luo Xiao-Lin; Liang Feng; Cheng Shuang; Li An-Lin

    2006-01-01

    The multi-charged sulfur ions of Sq+ (q ≤ 6) have been generated when hydrogen sulfide cluster beams are irradiated by a nanosecond laser of 1064 and 532 nm with an intensity of 1010 ~ 1012W·cm-2. S6+ is the dominant multicharged species at 1064 nm, while S4+, S3+ and S2+ ions are the main multi-charged species at 532 nm. A three-step model (i.e., multiphoton ionization triggering, inverse bremsstrahlung heating, electron collision ionizing) is proposed to explain the generation of these multi-charged ions at the laser intensity stated above. The high ionization level of the clusters and the increasing charge state of the ion products with increasing laser wavelength are supposed mainly due to the rate-limiting step, i.e., electron heating by absorption energy from the laser field via inverse bremsstrahlung, which is proportional to λ2, λ being the laser wavelength.

  16. A kinetic model of the hydrogen assisted selective catalytic reduction of NO with ammonia over Ag/Al2O3

    DEFF Research Database (Denmark)

    Tamm, Stefanie; Olsson, Louise; Fogel, Sebastian;

    2013-01-01

    of the reaction mechanism for NH3-SCR. Therefore, the model needs to be simple and accurately predict the conversion of NOx. The reduction of NO is described by a global reaction, with a molar stoichiometry between NO, NH3 and H2 of 1:1:2. Further reactions included in the model are the oxidation of NH3 to N2......A global kinetic model which describes H2-assisted NH3-SCR over an Ag/Al2O3 monolith catalyst has been developed. The intention is that the model can be applied for dosing NH3 and H2 to an Ag/Al2O3 catalyst in a real automotive application as well as contribute to an increased understanding...... and NO, oxidation of H2, and the adsorption and desorption of NH3. The model was fitted to the results of an NH3-TPD experiment, an NH3 oxidation experiment, and a series of H2-assisted NH3-SCR steady-state experiments. The model predicts the conversion of NOx well even during transient experiments....

  17. Hydrogen attack - Influence of hydrogen sulfide. [on carbon steel

    Science.gov (United States)

    Eliezer, D.; Nelson, H. G.

    1978-01-01

    An experimental study is conducted on 12.5-mm-thick SAE 1020 steel (plain carbon steel) plate to assess hydrogen attack at room temperature after specimen exposure at 525 C to hydrogen and a blend of hydrogen sulfide and hydrogen at a pressure of 3.5 MN/sq m for exposure times up to 240 hr. The results are discussed in terms of tensile properties, fissure formation, and surface scales. It is shown that hydrogen attack from a high-purity hydrogen environment is severe, with the formation of numerous methane fissures and bubbles along with a significant reduction in the room-temperature tensile yield and ultimate strengths. However, no hydrogen attack is observed in the hydrogen/hydrogen sulfide blend environment, i.e. no fissure or bubble formation occurred and the room-temperature tensile properties remained unchanged. It is suggested that the observed porous discontinuous scale of FeS acts as a barrier to hydrogen entry, thus reducing its effective equilibrium solubility in the iron lattice. Therefore, hydrogen attack should not occur in pressure-vessel steels used in many coal gasification processes.

  18. A Cross-Cultural Study of the Effect of a Graph-Oriented Computer-Assisted Project-Based Learning Environment on Middle School Students' Science Knowledge and Argumentation Skills

    Science.gov (United States)

    Hsu, P.-S.; Van Dyke, M.; Chen, Y.; Smith, T. J.

    2016-01-01

    The purpose of this mixed-methods study was to explore how seventh graders in a suburban school in the United States and sixth graders in an urban school in Taiwan developed argumentation skills and science knowledge in a project-based learning environment that incorporated a graph-oriented, computer-assisted application (GOCAA). A total of 42…

  19. A Cross-Cultural Study of the Effect of a Graph-Oriented Computer-Assisted Project-Based Learning Environment on Middle School Students' Science Knowledge and Argumentation Skills

    Science.gov (United States)

    Hsu, P.-S.; Van Dyke, M.; Chen, Y.; Smith, T. J.

    2016-01-01

    The purpose of this mixed-methods study was to explore how seventh graders in a suburban school in the United States and sixth graders in an urban school in Taiwan developed argumentation skills and science knowledge in a project-based learning environment that incorporated a graph-oriented, computer-assisted application (GOCAA). A total of 42…

  20. Future hybrid systems: solar and hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Kazmerski, L.L. [National Renewable Energy Lab., Golden, CO (United States); Broussard, K. [National Renewable Energy Lab., Golden, CO (United States)]|[NREL MURA Intern from Southern Univ., Baton Rouge, LA (United States)

    2003-07-01

    Future solar and hydrogen hybrid systems are discussed in terms of the evolving hydrogen economy. The focus is on distributed hydrogen, relying on the same distributed-energy strengths of solar-photovoltaic electricity in the built environment. Solar-hydrogen residences, as well as solar parks, are presented. Landarea issues are evaluated, and the economics and potential of these approaches are examined in terms of roadmap predictions on PV and hydrogen pathways. (orig.)

  1. The Analysis of Corrosion Situationabout the Spherical Tanks in the Wet Hydrogen Sulfide Environment%湿硫化氢环境下的球罐腐蚀状况分析

    Institute of Scientific and Technical Information of China (English)

    李海涛

    2014-01-01

    The corrosion situation of spherical tanks in the wet hydrogen sulfide environment was introduced , and the corrosion mechanisms were also analyzed in detail , as well as on influence factors of the low temperature wet hydrogen sulfide corrosion of hydro treating unit in petrochemical installations.Some wet hydrogen sulfide corrosion situations in hydro treating unit were summarized.The concrete reason of stress corrosion cracking and hydrogen knobbing with the actual working condition was obtained.The improvement measures and the matters needing attention in use were proposed.%阐述并分析了湿硫化氢环境下的球罐腐蚀状况,对球罐腐蚀机理及状况原因进行了详细的分析,以及对湿硫化氢腐蚀的影响因素,简述了一些加氢处理装置中湿硫化氢腐蚀的具体状况。结合实际工况,分析了其失效原因中发生应力腐蚀开裂或氢鼓包的具体原因,提出了改进措施及使用中的注意事项。

  2. Charge-density analysis using multipolar atom and spherical charge models: 2-methyl-1,3-cyclopentanedione, a compound displaying a resonance-assisted hydrogen bond.

    Science.gov (United States)

    Nassour, Ayoub; Kubicki, Maciej; Wright, Jonathan; Borowiak, Teresa; Dutkiewicz, Grzegorz; Lecomte, Claude; Jelsch, Christian

    2014-04-01

    The experimental charge-density distribution in 2-methyl-1,3-cyclopentanedione in the crystal state was analyzed by synchrotron X-ray diffraction data collection at 0.33 Å resolution. The molecule in the crystal is in the enol form. The experimental electron density was refined using the Hansen-Coppens multipolar model and an alternative modeling, based on spherical atoms and additional charges on the covalent bonds and electron lone-pair sites. The crystallographic refinements, charge-density distributions, molecular electrostatic potentials, dipole moments and intermolecular interaction energies obtained from the different charge-density models were compared. The experimental results are also compared with the theoretical charge densities using theoretical structure factors obtained from periodic quantum calculations at the B3LYP/6-31G** level. A strong intermolecular O-H···O hydrogen bond connects molecules along the [001] direction. The deformation density maps show the resonance within the O=C-C=C-OH fragment and merged lone pair lobes on the hydroxyl O atom. This resonance is further confirmed by the analysis of charges and topology of the electron density.

  3. Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-09-01

    This 2-page fact sheet provides a brief introduction to hydrogen production technologies. Intended for a non-technical audience, it explains how different resources and processes can be used to produce hydrogen. It includes an overview of research goals as well as “quick facts” about hydrogen energy resources and production technologies.

  4. Hydrogen storage

    NARCIS (Netherlands)

    Peters, C.J.; Sloan, E.D.

    2005-01-01

    The invention relates to the storage of hydrogen. The invention relates especially to storing hydrogen in a clathrate hydrate. The clathrate hydrate according to the present invention originates from a composition, which comprises water and hydrogen, as well as a promotor compound. The promotor comp

  5. Imaging Hydrogen Bond in Real Space

    CERN Document Server

    Chen, Xiu; Liu, Lacheng; Liu, Xiaoqing; Cai, Yingxing; Liu, Nianhua; Wang, Li

    2013-01-01

    Hydrogen bond is often assumed to be a purely electrostatic interaction between a electron-deficient hydrogen atom and a region of high electron density. Here, for the first time, we directly image hydrogen bond in real space by room-temperature scanning tunneling microscopy (STM) with the assistance of resonant tunneling effect in double barrier mode. STM observations demonstrate that the C=O:HO hydrogen bonds lifted several angstrom meters above metal surfaces appear shuttle-like features with a significant contrast along the direction connected the oxygen and hydrogen atoms of a single hydrogen bond. The off-center location of the summit and the variance of the appearance height for the hydrogen bond with scanning bias reveal that there are certain hybridizations between the electron orbitals of the involved oxygen and hydrogen atoms in the C=O:HO hydrogen bond.

  6. Shape-Controlled Generation of Gold Nanoparticles Assisted by Dual-Molecules: The Development of Hydrogen Peroxide and Oxidase-Based Biosensors

    Directory of Open Access Journals (Sweden)

    Chifang Peng

    2014-01-01

    Full Text Available With the assist of dual-molecules, 2-(N-morpholinoethanesulfonic acid (MES and sodium citrate, gold nanoparticles (GNPs with different shapes can be generated in the H2O2-mediated reduction of chloroauric acid. This one-pot reaction can be employed to sensitively detect H2O2, probe substrates or enzymes in oxidase-based reactions as well as prepare branched GNPs controllably. By the “naked eye,” 20 μM H2O2, 0.1 μM glucose, and 0.26 U/mL catalase could be differentiated, respectively. By spectrophotometer, the detected limits of H2O2, glucose, and catalase were 1.0 μM, 0.01 μM, and 0.03 U/mL, respectively, and the detection linear ranges for them were 5.0–400 μM, 0.01–0.3 mM, and 0.03–0.78 U/mL, respectively. The proposed “dual-molecules assist” strategy probably paves a new way for the fabrication of nanosensors based on the growth of anisotropic metal nanoparticles, and the developed catalase sensor can probably be utilized to fabricate ultrasensitive ELISA methods for various analytes.

  7. The operational performance of hydrogen masers in the deep space network: The performance of laboratory reference frequency standards in an operational environment

    Science.gov (United States)

    Ward, S. C.

    1981-01-01

    Hydrogen masers used as aids in meeting the routine frequency and time operational requirements within the 64 m antenna Deep Space Network. Both the operational syntonation (frequency synchronization) and the the clock (epoch) synchronization requirements were established through the use of specifically calibrated H-P E215061A flying clock. The sync/synt to UTC was maintained using LORAN and TV in simultaneous reception mode. The sync/synt within the 64 m net was maintained through the use of very long base interferometry. Results indicate that the hydrogen masers perform well within the required specifications.

  8. Corrosion Resistance of AISI 316L Coated with an Air-Cured Hydrogen Silsesquioxane Based Spin-On-Glass Enamel in Chloride Environment

    DEFF Research Database (Denmark)

    Lampert, Felix; Bruun Christiansen, Alexander; Din, Rameez Ud

    2017-01-01

    The efficiency of thin hydrogen silsesquioxane (HSQ) -based corrosion barrier coatings on 316 Lsubstrates after oxidative thermal curing at 400-550 ºC in air was investigated. Infrared spectroscopy and electrochemical impedance spectroscopy showed that an increasing curing temperature leads to pr...

  9. Single crystal electron paramagnetic resonance spectra of Cu(II) ions in Cu(tyrosine)(2): a study of weak exchange interactions mediated by resonance assisted hydrogen bonds (RAHB).

    Science.gov (United States)

    Paredes-García, Verónica; Santana, Ricardo C; Madrid, Rosa; Baldo, Bianca; Vega, Andrés; Spodine, Evgenia

    2012-09-01

    EPR measurements have been performed on single crystals of [Cu(L-tyrosine)(2)](∞) at 33.8 GHz and at room temperature. The EPR spectra display partially resolved EPR lines for most orientations of the magnetic field in the ab plane, and only one resonance for orientations close to the crystal axes, while only a single line is observed along any direction in the ca and cb crystal planes. This behavior is a result of the selective collapse of the resonances corresponding to the four copper sites in the unit cell produced by the exchange interactions between the copper ions. The magnitudes of the exchange interactions between the copper ions were evaluated from the angular variation of the line width and the collapse of the EPR lines. The value |J(AD)/k(B)|=0.8 K between neighboring copper atoms at 4.942 Å is assigned to a syn-anti equatorial-apical carboxylate bridge with a total bond length of 6.822 Å, while the small value |J(AB)/k(B)|=0.004 K is assigned to a long bridge of 11 atoms with a total bond length of 19.186 Å, that includes one resonance assisted hydrogen bond (RAHB). This finding is discussed in terms of values obtained for similar paths in other model compounds and in proteins.

  10. Hydrogen Spectrum

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    The series of absorption or emission lines that are characteristic of the hydrogen atom. According to the Bohr theory of the hydrogen atom, devised by Danish physicist Neils Bohr (1885-1962) in 1913, the hydrogen atom can be envisaged as consisting of a central nucleus (a proton) around which a single electron revolves. The electron is located in one of a number of possible permitted orbits, each...

  11. Phased Array Detection and Tolerance Analysis on the Base Metal Interlayer of Pressure Equipment in the Hydrogen Environment%临氢承压设备母材夹层的相控阵检测及容限分析

    Institute of Scientific and Technical Information of China (English)

    李修能; 路笃辉; 姜海一; 陈彦泽; 吴远建; 孙小华

    2015-01-01

    When the pressure equipment runs in the hydrogen and wet hydrogen sulifde environment, it’s easy to form interlayer lfaws which will directly affect the quality and safety of pressure equipment. To ifnd a new useful testing method solving this problem, we used Phased Array Ultrasonic Testing (PAUT) to detect an interlayer lfaw and brielfy analyzed it. At the same time, according to the API 579—2007, Allowable Limit Analysis is used to analyze the surrounding hydrogen blistering of the interlayer lfaw to assess the security of continued using.%当钢制承压设备在临氢以及湿硫化氢环境下运行时,很容易形成夹层缺陷,直接影响到承压设备的质量和安全,带来严重的后果。本文利用相控阵检测技术(PAUT)对夹层缺陷进行了检测,并对检测结果进行简要分析,以期为夹层缺陷检测提供另一种可行的检测方法。同时,依据API 579—2007对夹层缺陷的周围的氢鼓泡进行容限分析,以评估承压设备继续使用的安全性。

  12. In-situ oxide layer analysis of alloy 182 using electrochemical impedance spectroscopy in high dissolved hydrogen condition in PWR environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho-Sub; Subramanian, Gokul Obulan; Hong, Jong-Dae; Lee, Junho; Jang, Changheui [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    Alloy 82/182 weld metals had been extensively used in joining the components of the PWR primary system. Unfortunately, the cracking caused by PWSCC usually occurs on Alloy 82/182 dissimilar metal welds (DMW). Previous studies indicated that the susceptibility of PWSCC is closely related to the oxide characteristics which are dependent on water chemistry condition, especially dissolved hydrogen (DH). Furthermore, in primary system of pressurized water reactor (PWR), crack initiation resulted from electrochemical instability of oxide film of Ni-base structural materials in various hydrogen concentrations. In this study, in-situ oxide analysis of Alloy 182 using electrochemical impedance spectroscopy (EIS) was performed in high dissolved hydrogen condition. Especially, to understand the effects of tensile loading on the oxide characteristics, we tried to characterize the oxides formed on the tensile loaded specimen using in-situ EIS analysis. The EIS analysis of oxide on Alloy 182 was performed. The increase of oxide film thickness was observed with the increase of exposure time. To analysis the multi-layer structure of oxides, an equivalent model was obtained by fitting EIS data. It is assumed that overall oxide structures were composed of 3 layers approximately.

  13. Color Changing Hydrogen Sensors

    Science.gov (United States)

    Roberson, Luke B.; Williams, Martha; Captain, Janine E.; Mohajeri, Nahid; Raissi, Ali

    2015-01-01

    During the Space Shuttle Program, one of the most hazardous operation that occurred was the loading of liquid hydrogen (LH2) during fueling operations of the spacecraft. Due to hydrogen's low explosive limit, any amount leaked could lead to catastrophic event. Hydrogen's chemical properties make it ideal as a rocket fuel; however, the fuel is deemed unsafe for most commercial use because of the inability to easily detect the gas leaking. The increased use of hydrogen over traditional fossil fuels would reduce greenhouse gases and America's dependency on foreign oil. Therefore a technology that would improve safety at NASA and in the commercial sector while creating a new economic sector would have a huge impact to NASA's mission. The Chemochromic Detector for sensing hydrogen gas leakage is a color-changing detector that is useful in any application where it is important to know not only the presence but also the location of the hydrogen gas leak. This technology utilizes a chemochromicpigment and polymer matrix that can be molded or spun into rigid or pliable shapes useable in variable temperature environments including atmospheres of inert gas, hydrogen gas, or mixtures of gases. A change in color of the detector material indicates where gaseous hydrogen leaks are occurring. The irreversible sensor has a dramatic color change from beige to dark grey and remains dark grey after exposure. A reversible pigment changes from white to blue in the presence of hydrogen and reverts back to white in the presence of oxygen. Both versions of the sensor's pigments were comprised of a mixture of a metal oxide substrate and a hydro-chromic compound (i.e., the compound that changed color in the presence of hydrogen) and immediately notified the operator of the presence of low levels of hydrogen. The detector can be used in a variety of formats including paint, tape, caulking, injection molded parts, textiles and fabrics, composites, and films. This technology brings numerous

  14. Hydrogen Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-01

    The Hydrogen Bibliography is a compilation of research reports that are the result of research funded over the last fifteen years. In addition, other documents have been added. All cited reports are contained in the National Renewable Energy Laboratory (NREL) Hydrogen Program Library.

  15. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  16. Hydrogen carriers

    Science.gov (United States)

    He, Teng; Pachfule, Pradip; Wu, Hui; Xu, Qiang; Chen, Ping

    2016-12-01

    Hydrogen has the potential to be a major energy vector in a renewable and sustainable future energy mix. The efficient production, storage and delivery of hydrogen are key technical issues that require improvement before its potential can be realized. In this Review, we focus on recent advances in materials development for on-board hydrogen storage. We highlight the strategic design and optimization of hydrides of light-weight elements (for example, boron, nitrogen and carbon) and physisorbents (for example, metal-organic and covalent organic frameworks). Furthermore, hydrogen carriers (for example, NH3, CH3OH-H2O and cycloalkanes) for large-scale distribution and for on-site hydrogen generation are discussed with an emphasis on dehydrogenation catalysts.

  17. Florida Hydrogen Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Block, David L

    2013-06-30

    The Florida Hydrogen Initiative (FHI) was a research, development and demonstration hydrogen and fuel cell program. The FHI program objectives were to develop Florida?s hydrogen and fuel cell infrastructure and to assist DOE in its hydrogen and fuel cell activities The FHI program funded 12 RD&D projects as follows: Hydrogen Refueling Infrastructure and Rental Car Strategies -- L. Lines, Rollins College This project analyzes strategies for Florida's early stage adaptation of hydrogen-powered public transportation. In particular, the report investigates urban and statewide network of refueling stations and the feasibility of establishing a hydrogen rental-car fleet based in Orlando. Methanol Fuel Cell Vehicle Charging Station at Florida Atlantic University ? M. Fuchs, EnerFuel, Inc. The project objectives were to design, and demonstrate a 10 kWnet proton exchange membrane fuel cell stationary power plant operating on methanol, to achieve an electrical energy efficiency of 32% and to demonstrate transient response time of less than 3 milliseconds. Assessment of Public Understanding of the Hydrogen Economy Through Science Center Exhibits, J. Newman, Orlando Science Center The project objective was to design and build an interactive Science Center exhibit called: ?H2Now: the Great Hydrogen Xchange?. On-site Reformation of Diesel Fuel for Hydrogen Fueling Station Applications ? A. Raissi, Florida Solar Energy Center This project developed an on-demand forecourt hydrogen production technology by catalytically converting high-sulfur hydrocarbon fuels to an essentially sulfur-free gas. The removal of sulfur from reformate is critical since most catalysts used for the steam reformation have limited sulfur tolerance. Chemochromic Hydrogen Leak Detectors for Safety Monitoring ? N. Mohajeri and N. Muradov, Florida Solar Energy Center This project developed and demonstrated a cost-effective and highly selective chemochromic (visual) hydrogen leak detector for safety

  18. Dental Assistants

    Science.gov (United States)

    ... Z INDEX | OOH SITE MAP | EN ESPAÑOL Healthcare > Dental Assistants PRINTER-FRIENDLY EN ESPAÑOL Summary What They ... of workers and occupations. What They Do -> What Dental Assistants Do About this section Assistants prepare and ...

  19. Surgical Assisting

    Science.gov (United States)

    ... Insert and remove Foley urinary bladder catheter Place pneumatic tourniquet Confirm procedure with surgeon Drape patient within ... Technology and Surgical Assisting (NBSTSA) offers the CertifiedSurgical First Assistant (CSFA) credential, and the National Surgical Assistant ...

  20. The formation and structure of the oxide and hydroxide chemisorbed phases at the aluminum surface, and relevance to hydrogen embrittlement

    Science.gov (United States)

    Francis, Michael; Kelly, Robert; Neurock, Matthew

    2010-03-01

    Aluminum alloys used in aerospace structures are susceptible to environmentally assisted cracking (EAC) induced by hydrogen embrittlement (HE) (Gangloff and Ives 1990). Crack growth experiments have demonstrated a linear relation between the relative humidity of the environment and crack growth rates, indicating the importance of water (Speidel and Hyatt 1972). While the presence of water has been demonstrated to be necessary for EAC of aluminum, crack growth rates have been linked to the diffusivity of hydrogen in aluminum (Gangloff 2003) and hydrogen densities at the crack tip as high as Al2H have been observed (Young and Scully 1998). While the mechanism by which hydrogen embrittles aluminum is yet not well understood, without the entry of hydrogen into the aluminum matrix, embrittlement would not occur. While at the crack tip high hydrogen concentrations exist, the solubility of hydrogen in aluminum is normal near 1 ppm (Wolverton 2004). In this work combined first principles and kinetic Monte Carlo methods will be used to examine the oxide and hydroxide structure resulting from exposure of aluminum to H2O or O2 and relevance to hydrogen entry as well as EAC is discussed.

  1. Hydrogen Assisted Fracture of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sugar, Joshua Daniel; Somerday, Brian P.; Homer, Mark; Vitale, Suzy; Matsuda, Junko

    2016-02-01

    The Enhanced Surveillance Sub-program has an annual NNSA requirement to submit a comprehensive report on all our fiscal year activities right after the start of the next calendar year. As most of you know, we collate all of our PI task submissions into a single volume that we send to NNSA, our customers, and use for other programmatic purposes. The functional objective of this report is to formally document the purpose, status, and accomplishments and impacts of all our work. For your specific submission, please follow the instructions described below and use the template provided. These are essentially the same as was used last year. We recognize this report may also include information on specific age-related findings that you will provide again in a few months as input to the Stockpile Annual Assessment process (e.g., in the submittal of your Component Assessment Report). However, the related content of your ES AR input should provide an excellent foundation that can simply be updated as needed for your Annual Assessment input.

  2. Identifying Reaction Pathways and their Environments

    DEFF Research Database (Denmark)

    Maronsson, Jon Bergmann

    )2 and Mg(BH4)2, experiments on low temperature rotational dynamics were performed. The work presented here revolved around assisting in the data analysis by performing density functional theory calculations on the possible dynamical events. For the Mg(BH4)2, in good agreement with the experiments, C2-type...... extensions to further identify the reaction environment for a more accurate rate. Complex borohydrides are materials of high hydrogen storage capacity and high thermodynamic stability (too high for hydrogen storage). In an effort to gain insight into the structural transitions of two such materials, Ca(BH4...... rotations occur at lower temperature than C3-type rotations and approximately 15% of the BH4 units activate at a lower temperature than the rest. For the Ca(BH4)2, in addition to the rotational dynamics, an unidentified event was detected which, according to the calculations was most likely due to H2...

  3. Studies on the Tolerating Mechanism for Sulfide in Urechis unicinctus ( Echiura : Urechidae) ——Cytological Observation on Urechis unicinctus in Different Hydrogen Sulfide Environment

    Institute of Scientific and Technical Information of China (English)

    张志峰; 邵明瑜; 康庆浩; 金在敏

    2003-01-01

    This study on the cytological changes of the body wall, aspiratory intestine and crissalbursa in Urechis unicinctus by light microscope (LM) and transmission electron microscope (TEM)showed that the difference between the body wall and the natural environment rich in H2 S was notobvious; that the wall color of the aspiratory intestine in H2 S rich environment changed from normalsemitransparency to dark brown; that its epithelia were disassembled and the electron density of itscytoplasm matrix was lower; and that in H2 S rich enviromnent many basophilic granules occurred inthe epithelia of the crissal bursa. Granules with single membrane and myelinefingure were foundwith TEM.

  4. Applied Stress Affecting the Environmentally Assisted Cracking

    Science.gov (United States)

    Vasudevan, A. K.

    2013-03-01

    Stress corrosion cracking (SCC) is affected by the mode of applied stress, i.e., tension, compression, or torsion. The cracking is measured in terms of initiation time to nucleate a crack or time to failure. In a simple uniaxial loading under tension or compression, it is observed that the initiation time can vary in orders of magnitude depending on the alloy and the environment. Fracture can be intergranular or transgranular or mixed mode. Factors that affect SCC are solubility of the metal into surrounding chemical solution, and diffusion rate (like hydrogen into a tensile region) of an aggressive element into the metal and liquid metallic elements in the grain boundaries. Strain hardening exponent that affects the local internal stresses and their gradients can affect the diffusion kinetics. We examine two environments (Ga and 3.5 pct NaCl) for the same alloy 7075-T651, under constant uniaxial tension and compression load. These two cases provide us application to two different governing mechanisms namely liquid metal embrittlement (7075-Ga) and hydrogen-assisted cracking (7075-NaCl). We note that, in spite of the differences in their mechanisms, both systems show similar behavior in the applied K vs crack initiation time plots. One common theme among them is the transport mechanism of a solute element to a tensile-stress region to initiate fracture.

  5. Assessment of biological Hydrogen production processes: A review

    Science.gov (United States)

    Najafpour, G. D.; Shahavi, M. H.; Neshat, S. A.

    2016-06-01

    Energy crisis created a special attention on renewable energy sources. Among these sources; hydrogen through biological processes is well-known as the most suitable and renewable energy sources. In terms of process yield, hydrogen production from various sources was evaluated. A summary of microorganisms as potential hydrogen producers discussed along with advantages and disadvantages of several bioprocesses. The pathway of photo-synthetic and dark fermentative organisms was discussed. In fact, the active enzymes involved in performance of biological processes for hydrogen generation were identified and their special functionalities were discussed. The influential factors affecting on hydrogen production were known as enzymes assisting liberation specific enzymes such as nitrogenase, hydrogenase and uptake hydrogenase. These enzymes were quite effective in reduction of proton and form active molecular hydrogen. Several types of photosynthetic systems were evaluated with intension of maximum hydrogen productivities. In addition dark fermentative and light intensities on hydrogen productions were evaluated. The hydrogen productivities of efficient hydrogen producing strains were evaluated.

  6. Nitrogen-Doped Nanoporous Carbon Membranes with Co/CoP Janus-Type Nanocrystals as Hydrogen Evolution Electrode in Both Acidic and Alkaline Environments

    KAUST Repository

    Wang, Hong

    2017-03-31

    Self-supported electrocatalysts being generated and employed directly as electrodes for energy conversion has been intensively pursued in the fields of materials chemistry and energy. Herein, we report a synthetic strategy to prepare freestanding hierarchically structured, nitrogen-doped nanoporous graphitic carbon membranes functionalized with Janus-type Co/CoP nanocrystals (termed as HNDCM-Co/CoP), which were successfully applied as a highly efficient, binder-free electrode in the hydrogen evolution reaction (HER). Benefited from multiple structural merits, such as a high degree of graphitization, three-dimensionally interconnected micro/meso/macropores, uniform nitrogen doping, well-dispersed Co/CoP nanocrystals, as well as the confinement effect of the thin carbon layer on the nanocrystals, HNDCM-Co/CoP exhibited superior electrocatalytic activity and long-term operation stability for HER under both acidic and alkaline conditions. As a proof-of-concept of practical usage, a 5.6 cm × 4 cm × 60 μm macroscopic piece of HNDCM-Co/CoP was prepared in our laboratory. Driven by a solar cell, electroreduction of water in alkaline conditions (pH 14) was performed, and H was produced at a rate of 16 mL/min, demonstrating its potential as real-life energy conversion systems.

  7. Hydrogen program overview

    Energy Technology Data Exchange (ETDEWEB)

    Gronich, S. [Dept. of Energy, Washington, DC (United States). Office of Utility Technologies

    1997-12-31

    This paper consists of viewgraphs which summarize the following: Hydrogen program structure; Goals for hydrogen production research; Goals for hydrogen storage and utilization research; Technology validation; DOE technology validation activities supporting hydrogen pathways; Near-term opportunities for hydrogen; Market for hydrogen; and List of solicitation awards. It is concluded that a full transition toward a hydrogen economy can begin in the next decade.

  8. Hydrogen and OUr Energy Future

    Energy Technology Data Exchange (ETDEWEB)

    Rick Tidball; Stu Knoke

    2009-03-01

    In 2003, President George W. Bush announced the Hydrogen Fuel Initiative to accelerate the research and development of hydrogen, fuel cell, and infrastructure technologies that would enable hydrogen fuel cell vehicles to reach the commercial market in the 2020 timeframe. The widespread use of hydrogen can reduce our dependence on imported oil and benefit the environment by reducing greenhouse gas emissions and criteria pollutant emissions that affect our air quality. The Energy Policy Act of 2005, passed by Congress and signed into law by President Bush on August 8, 2005, reinforces Federal government support for hydrogen and fuel cell technologies. Title VIII, also called the 'Spark M. Matsunaga Hydrogen Act of 2005' authorizes more than $3.2 billion for hydrogen and fuel cell activities intended to enable the commercial introduction of hydrogen fuel cell vehicles by 2020, consistent with the Hydrogen Fuel Initiative. Numerous other titles in the Act call for related tax and market incentives, new studies, collaboration with alternative fuels and renewable energy programs, and broadened demonstrations--clearly demonstrating the strong support among members of Congress for the development and use of hydrogen fuel cell technologies. In 2006, the President announced the Advanced Energy Initiative (AEI) to accelerate research on technologies with the potential to reduce near-term oil use in the transportation sector--batteries for hybrid vehicles and cellulosic ethanol--and advance activities under the Hydrogen Fuel Initiative. The AEI also supports research to reduce the cost of electricity production technologies in the stationary sector such as clean coal, nuclear energy, solar photovoltaics, and wind energy.

  9. A cohesive zone framework for environmentally assisted fatigue

    DEFF Research Database (Denmark)

    del Busto, Susana; Betegón, Covadonga; Martínez Pañeda, Emilio

    2017-01-01

    We present a compelling finite element framework to model hydrogen assisted fatigue by means of a hydrogen- and cycle-dependent cohesive zone formulation. The model builds upon: (i) appropriate environmental boundary conditions, (ii) a coupled mechanical and hydrogen diffusion response, driven...

  10. Hydrogen-bond acidity of OH groups in various molecular environments (phenols, alcohols, steroid derivatives, and amino acids structures): experimental measurements and density functional theory calculations.

    Science.gov (United States)

    Graton, Jérôme; Besseau, François; Brossard, Anne-Marie; Charpentier, Eloïse; Deroche, Arnaud; Le Questel, Jean-Yves

    2013-12-12

    The hydrogen-bond (H-bond) donating strengths of a series of 36 hydroxylic H-bond donors (HBDs) with N-methylpyrrolidinone have been measured in CCl4 solution by FTIR spectrometry. These data allow the definition of a H-bond acidity scale named pKAHY covering almost three pK units, corresponding to 16 kJ mol(-1). These results are supplemented by equilibrium constants determined in CH2Cl2 for one-third of the data set to study compounds showing a poor solubility in CCl4. A systematic comparison of these experimental results with theoretical data computed in the gas phase using DFT (density functional theory) calculations has also been carried out. Quantum electrostatic parameters appear to accurately describe the H-bond acidity of the hydroxyl group, whereas partial atomic charges according to the Merz-Singh-Kollman and CHelpG schemes are not suitable for this purpose. A substantial decrease of the H-bond acidity of the OH group is pointed out when the hydroxyl moiety is involved in intramolecular H-bond interactions. In such situations, the interactions are further characterized through AIM and NBO analyses, which respectively allow localizing the corresponding bond critical point and the quantification of a significant charge transfer from the available lone pair to the σ*OH antibonding orbital. Eventually, the H-bond ability of the hydroxyl groups of steroid derivatives and of lateral chains of amino acids are evaluated on the basis of experimental and/or theoretical data.

  11. ROBOTIC ASSISTANCE IN SPINE SURGERY

    Directory of Open Access Journals (Sweden)

    N. A. Konovalov

    2010-01-01

    Full Text Available Robotic assistance recently gains increasing popularity in spinal surgery. Robotic assistance provides higher effectiveness and safety especially in complex anatomy environment. 16 patients with degenerative disc disease were operated with robotic assistance device («SpineAssist»; MAZOR Surgical Technologies, Caesarea, Israel. The robot was used for automated intraoperative positioning of the instruments according to preoperatively planned trajectories. Robotic assistance enabled optimal screw placement even in complex anatomical cases (thin pedicles and rotational deformity. No implant-related complications were recorded.

  12. Assistive Technology

    Science.gov (United States)

    ... Page Resize Text Printer Friendly Online Chat Assistive Technology Assistive technology (AT) is any service or tool that helps ... be difficult or impossible. For older adults, such technology may be a walker to improve mobility or ...

  13. Assistive Technologies

    Science.gov (United States)

    Auat Cheein, Fernando A., Ed.

    2012-01-01

    This book offers the reader new achievements within the Assistive Technology field made by worldwide experts, covering aspects such as assistive technology focused on teaching and education, mobility, communication and social interactivity, among others. Each chapter included in this book covers one particular aspect of Assistive Technology that…

  14. Metallic Hydrogen

    Science.gov (United States)

    Silvera, Isaac; Zaghoo, Mohamed; Salamat, Ashkan

    2015-03-01

    Hydrogen is the simplest and most abundant element in the Universe. At high pressure it is predicted to transform to a metal with remarkable properties: room temperature superconductivity, a metastable metal at ambient conditions, and a revolutionary rocket propellant. Both theory and experiment have been challenged for almost 80 years to determine its condensed matter phase diagram, in particular the insulator-metal transition. Hydrogen is predicted to dissociate to a liquid atomic metal at multi-megabar pressures and T =0 K, or at megabar pressures and very high temperatures. Thus, its predicted phase diagram has a broad field of liquid metallic hydrogen at high pressure, with temperatures ranging from thousands of degrees to zero Kelvin. In a bench top experiment using static compression in a diamond anvil cell and pulsed laser heating, we have conducted measurements on dense hydrogen in the region of 1.1-1.7 Mbar and up to 2200 K. We observe a first-order phase transition in the liquid phase, as well as sharp changes in optical transmission and reflectivity when this phase is entered. The optical signature is that of a metal. The mapping of the phase line of this transition is in excellent agreement with recent theoretical predictions for the long-sought plasma phase transition to metallic hydrogen. Research supported by the NSF, Grant DMR-1308641, the DOE Stockpile Stewardship Academic Alliance Program, Grant DE-FG52-10NA29656, and NASA Earth and Space Science Fellowship Program, Award NNX14AP17H.

  15. Hydrogen embrittlement and galvanic corrosion of titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Soh, Jeong Ryong; Jeong, Y. H.; Choi, B. K.; Baek, J. H.; Hwang, D. Y.; Choi, B. S.; Lee, D. J

    2000-06-01

    The material properties including the fracture behavior of titanium alloys used as a steam generator tube in SMART can be degraded de to the hydrogen embrittlement and the galvanic corrosion occurring as a result of other materials in contact with titanium alloys in a conducting corrosive environment. In this report the general concepts and trends of hydrogen embrittlement are qualitatively described to adequately understand and expect the fracture behavior from hydrogen within the bulk of materials and under hydrogen containing environments because hydrogen embrittlement may be very complicated process. And the characteristics of galvanic corrosion closely related to hydrogen embrittlement is qualitatively based on wimple electrochemical theory.

  16. Saga of hydrogen civilization

    Energy Technology Data Exchange (ETDEWEB)

    Veziroglu, T.N. [Univ. of Miami, Coral Gables, FL (United States). Clean Energy Research Institute

    2008-09-30

    In the 1960s, air pollution in cities became an important issue hurting the health of people. The author became interested in environmental issues in general and air pollution in particular. He started studying possible vehicle fuels, with a view of determining the fuel which would cause little or no pollution. He particularly studied methanol, ethanol, ammonia and hydrogen as well as the gasohols (i.e., the mixtures of gasoline and methanol and/or ethanol). His investigation of fuels for transportation lasted five years (1967-1972). The result was that hydrogen is the cleanest fuel, and it is also the most efficient one. It would not produce CO (carbon monoxide), CO{sub 2} (carbon dioxide), SO{sub x}, hydrocarbons, soot and particulates. If hydrogen was burned in oxygen, it would not produce NO{sub x} either. If it burned in air, there would then be some NO{sub x} produced. Since the author has always believed that engineers and scientists should strive to find solutions to the problems facing humankind and the world, he established the Clean Energy Research Institute (CERI) at the University of Miami in 1973. The mission of the Institute was to find a solution or solutions to the energy problem, so the world economy can function properly and provide humankind with high living standards. To find clean forms of energy was also the mission of the Institute, so that they would not produce pollution and damage the health of flora, fauna and humans, as well as the environment of the planet Earth as a whole. CERI looked at all of the possible primary energy sources, including solar, wind, currents, waves, tides, geothermal, nuclear breeders and thermonuclear. Although they are much cleaner and would last much longer than fossil fuels, these sources were not practical for use. They were not storable or transportable by themselves, except nuclear. They could not be used as a fuel for transportation by themselves, except nuclear for marine transportation. In order to solve

  17. Evaluation of Environmentally Assisted Cracking of Armour Wires in Flexible Pipes, Power Cables and Umbilicals

    Science.gov (United States)

    Zhang, Zhiying

    Environmentally assisted cracking (EAC) of armour wires in flexible pipes, power cables and umbilicals is a major concern with the development of oil and gas fields and wind farms in harsh environments. Hydrogen induced cracking (HIC) or hydrogen embrittlement (HE) of steel armour wires used in deep-water and ultra-deep-water has been evaluated. Simulated tests have been carried out in simulated sea water, under conditions where the susceptibility is the highest, i.e. at room temperature, at the maximum negative cathodic potential and at the maximum stress level expected in service for 150 hours. Examinations of the tested specimens have not revealed cracking or blistering, and measurement of hydrogen content has confirmed hydrogen charging. In addition, sulphide stress cracking (SSC) and chloride stress cracking (CSC) of nickel-based alloy armour wires used in harsh down-hole environments has been evaluated. Simulated tests have been carried out in simulated solution containing high concentration of chloride, with high hydrogen sulphide partial pressure, at high stress level and at 120 °C for 720 hours. Examinations of the tested specimens have not revealed cracking or blistering. Subsequent tensile tests of the tested specimens at ambient pressure and temperature have revealed properties similar to the as-received specimens.

  18. Housing Assistance

    Directory of Open Access Journals (Sweden)

    Emma Baker

    2013-07-01

    Full Text Available In Australia, an increasing number of households face problems of access to suitable housing in the private market. In response, the Federal and State Governments share responsibility for providing housing assistance to these, mainly low-income, households. A broad range of policy instruments are used to provide and maintain housing assistance across all housing tenures, for example, assisting entry into homeownership, providing affordability assistance in the private rental market, and the provision of socially owned and managed housing options. Underlying each of these interventions is the premise that secure, affordable, and appropriate housing provides not only shelter but also a number of nonshelter benefits to individuals and their households. Although the nonshelter outcomes of housing are well acknowledged in Australia, the understanding of the nonshelter outcomes of housing assistance is less clear. This paper explores nonshelter outcomes of three of the major forms of housing assistance provided by Australian governments—low-income mortgage assistance, social housing, and private rent assistance. It is based upon analysis of a survey of 1,353 low-income recipients of housing assistance, and specifically measures the formulation of health and well-being, financial stress, and housing satisfaction outcomes across these three assistance types. We find clear evidence that health, finance, and housing satisfaction outcomes are associated with quite different factors for individuals in these three major housing assistance types.

  19. Ventricular assist device

    Science.gov (United States)

    VAD; RVAD; LVAD; BVAD; Right ventricular assist device; Left ventricular assist device; Biventricular assist device; Heart pump; Left ventricular assist system; LVAS; Implantable ventricular assist device

  20. Hydrogen generation from renewable resources

    Energy Technology Data Exchange (ETDEWEB)

    Loges, Bjoern

    2009-09-04

    In this thesis, the hydrogen generation by dehydrogenation of 2-propanol and formic acid as model substances for renewable resources have been studied, which is of importance for hydrogen storage. For the base-assisted dehydrogenation of 2-propanol, a ruthenium diamine catalyst system has been investigated. For the selective decomposition of formic acid to hydrogen and carbon dioxide, a system has been established containing ruthenium catalysts and formic acid amine adducts as substrates. The best catalyst activity and productivity have been achieved with in situ generated ruthenium phosphine catalysts, e.g. [RuCl{sub 2}(benzene)]{sub 2} / dppe (TOF = 900 h{sup -1}, TON = 260,000). The gas evolved has been directly used in fuel cells. Furthermore, the influence of irradiation with visible light has been described for the ruthenium phosphine catalysts. (orig.)

  1. Saga of hydrogen civilization

    Energy Technology Data Exchange (ETDEWEB)

    Veziroglu, T.N. [Clean Energy Research Inst., Univ. of Miami, Coral Gables, Florida (United States)

    2009-07-01

    'Full text': Fossil fuels (i.e., petroleum, natural gas and coal), which meet most of the world's energy demand today, are being depleted quickly. Also, their combustion products are causing global problems such as the greenhouse effect, ozone layer depletion, acid rains and pollution, all of which are posing great danger for our environment and eventually for the life on our planet. Many engineers and scientists agree that the solution to these global problems would be to replace the existing fossil fuel system by the hydrogen energy system. Hydrogen is a very efficient and clean fuel. Its combustion will produce no greenhouse gases, no ozone layer depleting chemicals, and little or no acid rain ingredients and pollution. Hydrogen, produced from renewable energy (e.g., solar) sources, would result in a permanent energy system which we would never have to change. However, there are other energy systems proposed for the post-petroleum era, such as a synthetic fossil fuel system. In this system, synthetic gasoline and synthetic natural gas will be produced using abundant deposits of coal. In a way, this will ensure the continuation of the present fossil fuel system. The two possible energy systems for the post-fossil fuel era (i.e., the solar-hydrogen energy system and the synthetic fossil fuel system) are compared with the present fossil fuel system by taking into consideration production costs, environmental damages and utilization efficiencies. The results indicate that the solar-hydrogen energy system is the best energy system to ascertain a sustainable future, and it should replace the fossil fuel system before the end of the 21st century. (author)

  2. Accessibility and assistive products

    Science.gov (United States)

    Rodríguez-Porrero, Cristina

    2009-01-01

    Introduction Accessibility and assistive products and technologies are needed to ensure the rights of persons with disabilities and older persons. Many developments have been implemented in laws, standards, markets and from the consumers perspective, at international, European and national levels. The real issue is that not all the potential users benefit from the use of assistive products or accessible measures. Discussion Innovative methods are needed to allow all potential users to have real advantage of assistive technologies and accessible and design for all facilities. Best practices will be presented and existing gaps and recommendations will be discussed. Cost-benefits aspects will also be presented. Conclusion In order to get advantages from opportunities of globalization, hard work and responsibilities of all stakeholders are needed, so that assistive products and accessibility reach a whole range of situations and environments and contribute to ensure quality of life in a society for all.

  3. Mobile Autonomous Humanoid Assistant

    Science.gov (United States)

    Diftler, M. A.; Ambrose, R. O.; Tyree, K. S.; Goza, S. M.; Huber, E. L.

    2004-01-01

    A mobile autonomous humanoid robot is assisting human co-workers at the Johnson Space Center with tool handling tasks. This robot combines the upper body of the National Aeronautics and Space Administration (NASA)/Defense Advanced Research Projects Agency (DARPA) Robonaut system with a Segway(TradeMark) Robotic Mobility Platform yielding a dexterous, maneuverable humanoid perfect for aiding human co-workers in a range of environments. This system uses stereo vision to locate human team mates and tools and a navigation system that uses laser range and vision data to follow humans while avoiding obstacles. Tactile sensors provide information to grasping algorithms for efficient tool exchanges. The autonomous architecture utilizes these pre-programmed skills to form human assistant behaviors. The initial behavior demonstrates a robust capability to assist a human by acquiring a tool from a remotely located individual and then following the human in a cluttered environment with the tool for future use.

  4. Walker use, but not falls, is associated with lower physical functioning and health of residents in an assisted-living environment

    Directory of Open Access Journals (Sweden)

    Daniel A Andersen

    2007-04-01

    Full Text Available Daniel A Andersen1,5, Bernard A Roos1–4, Damian C Stanziano1,3, Natasha M Gonzalez3, Joseph F Signorile1–31Stein Gerontological Institute, Miami, FL; 2Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Miami, FL; 3Department of Exercise and Sport Sciences, University of Miami, Coral Gables, FL; 4Departments of Medicine and Neurology, University of Miami Miller School of Medicine, Miami, FL; 5Department of Epidemiology and Public Health, University of Miami School of Medicine, Miami, FL, USAAbstract: The relationship between perceived health and walker use has seldom been addressed. Concerns over falls and falls risk are precursors to walker use. We compared the SF-36 scores of 26 women and 14 men, mean age 86.8 ± 6.0 years based on walker use and faller status. An analysis of covariance (ANCOVA with age as the covariate, compared groups for the SF-36 constructs and totals score. Significant differences were noted between walker users and nonusers in physical functioning, role limitations due to physical problems, general health, and the total SF-36 score. Pairwise comparisons favored nonusers, while no differences were seen due to faller status. Walker use is associated with lower self-perceptions of physical functioning, role limitations due to physical problems, and general health in assisted-living residents. Faller status is not associated with self-perceived health status. Although walker use aids mobility and lowers the probability of falls, further research is needed to determine if the prescription of assistive devices has a more negative impact on self-perceived health than does falling. This possibility could be explained, in part, by the greater activity levels of those individuals who do not depend on walkers.Keywords: physical function, threshold, walking aid, elderly, perceived health

  5. Hydrogen as a fuel

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    A panel of the Committee on Advanced Energy Storage Systems of the Assembly of Engineering has examined the status and problems of hydrogen manufacturing methods, hydrogen transmission and distribution networks, and hydrogen storage systems. This examination, culminating at a time when rapidly changing conditions are having noticeable impact on fuel and energy availability and prices, was undertaken with a view to determining suitable criteria for establishing the pace, timing, and technical content of appropriate federally sponsored hydrogen R and D programs. The increasing urgency to develop new sources and forms of fuel and energy may well impact on the scale and timing of potential future hydrogen uses. The findings of the panel are presented. Chapters are devoted to hydrogen sources, hydrogen as a feedstock, hydrogen transport and storage, hydrogen as a heating fuel, automotive uses of hydrogen, aircraft use of hydrogen, the fuel cell in hydrogen energy systems, hydrogen research and development evaluation, and international hydrogen programs.

  6. The hydrogen; L'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The hydrogen as an energy system represents nowadays a main challenge (in a scientific, economical and environmental point of view). The physical and chemical characteristics of hydrogen are at first given. Then, the challenges of an hydrogen economy are explained. The different possibilities of hydrogen production are described as well as the distribution systems and the different possibilities of hydrogen storage. Several fuel cells are at last presented: PEMFC, DMFC and SOFC. (O.M.)

  7. Gaseous hydrogen embrittlement of high strength steels

    Science.gov (United States)

    Gangloff, R. P.; Wei, R. P.

    1977-01-01

    The effects of temperature, hydrogen pressure, stress intensity, and yield strength on the kinetics of gaseous hydrogen assisted crack propagation in 18Ni maraging steels were investigated experimentally. It was found that crack growth rate as a function of stress intensity was characterized by an apparent threshold for crack growth, a stage where the growth rate increased sharply, and a stage where the growth rate was unchanged over a significant range of stress intensity. Cracking proceeded on load application with little or no detectable incubation period. Gaseous hydrogen embrittlement susceptibility increased with increasing yield strength.

  8. The development of aqueous transfer hydrogenation catalysts.

    Science.gov (United States)

    Robertson, Andrew; Matsumoto, Takahiro; Ogo, Seiji

    2011-10-28

    This review discusses the development of aqueous phase, homogeneous, transfer hydrogenation catalysis. Transfer hydrogenation catalysts, based on Ru, Ir and Rh, reduce organic substrates in water by assisting the transfer of hydrogen from simple donor species. These catalysts are expected to have significant benefits when compared with organic phase catalysts, including greater activity, greater selectivity and smaller environmental impact. They will therefore be expected to make a significant contribution to homogeneous catalysis and 'green chemistry'. Here, we comprehensively examine these catalysts, paying special attention to structural features.

  9. Conversion of glycerol to hydrogen rich gas.

    Science.gov (United States)

    Tran, Nguyen H; Kannangara, G S Kamali

    2013-12-21

    Presently there is a glut of glycerol as the by-product of biofuel production and it will grow as production increases. The conundrum is how we can consume this material and convert it into a more useful product. One potential route is to reform glycerol to hydrogen rich gas including synthesis gas (CO + H2) and hydrogen. However, there is recent literature on various reforming techniques which may have a bearing on the efficiency of such a process. Hence in this review reforming of glycerol at room temperature (normally photo-catalytic), catalysis at moderate and high temperature and a non-catalytic pyrolysis process are presented. The high temperature processes allow the generation of synthesis gas with the hydrogen to carbon monoxide ratios being suitable for synthesis of dimethyl ether, methanol and for the Fischer-Tropsch process using established catalysts. Efficient conversion of synthesis gas to hydrogen involves additional catalysts that assist the water gas shift reaction, or involves in situ capture of carbon dioxide and hydrogen. Reforming at reduced temperatures including photo-reforming offers the opportunity of producing synthesis gas or hydrogen using single catalysts. Together, these processes will assist in overcoming the worldwide glut of glycerol, increasing the competitiveness of the biofuel production and reducing our dependency on the fossil based, hydrogen rich gas.

  10. Genetic Gains in Yield and Yield Related Traits under Drought Stress and Favorable Environments in a Maize Population Improved Using Marker Assisted Recurrent Selection

    Directory of Open Access Journals (Sweden)

    Folusho Bankole

    2017-05-01

    Full Text Available The objective of marker assisted recurrent selection (MARS is to increase the frequency of favorable marker alleles in a population before inbred line extraction. This approach was used to improve drought tolerance and grain yield (GY in a biparental cross of two elite drought tolerant lines. The testcrosses of randomly selected 50 S1 lines from each of the three selection cycles (C0, C1, C2 of the MARS population, parental testcrosses and the cross between the two parents (F1 were evaluated under drought stress (DS and well watered (WW well as under rainfed conditions to determine genetic gains in GY and other agronomic traits. Also, the S1 lines derived from each selection types were genotyped with single nucleotide polymorphism (SNP markers. Testcrosses derived from C2 produced significantly higher grain field under DS than those derived from C0 with a relative genetic gain of 7% per cycle. Also, the testcrosses of S1 lines from C2 showed an average genetic gain of 1% per cycle under WW condition and 3% per cycle under rainfed condition. Molecular analysis revealed that the frequency of favorable marker alleles increased from 0.510 at C0 to 0.515 at C2, while the effective number of alleles (Ne per locus decreased from C0 (1.93 to C2 (1.87. Our results underscore the effectiveness of MARS for improvement of GY under DS condition.

  11. Mechanisms and Kinetics of Environmentally Assisted Cracking: Current Status, Issues, and Suggestions for Further Work

    Science.gov (United States)

    Lynch, S. P.

    2013-03-01

    Mechanisms and kinetics of metal-induced embrittlement, hydrogen-embrittlement, and stress-corrosion cracking are discussed, and long-standing controversies are addressed by reviewing critical observations. Recommendations are also made regarding further work (including repetition of previous work using more advanced measurement and characterisation techniques) that should be carried out in order to resolve some of the contentious issues. The evidence to date suggests that adsorption-based mechanisms, involving weakening of substrate interatomic bonds so that dislocation emission or decohesion is facilitated, accounts for embrittlement in many systems. Embrittling adsorbed species include some metal atoms, hydrogen, and complex ions produced by de-alloying. Other viable mechanisms of embrittlement include those based on (1) dissolution of anodic grain-boundary regions, and (2) decohesion at grain boundaries owing to segregated hydrogen and impurities. The hydrogen-enhanced localised-plasticity mechanism, based on solute hydrogen facilitating dislocation activity in the plastic zone ahead of cracks, makes a contribution in some cases, but is relatively unimportant compared with these other mechanisms for most fracture modes. The film-induced cleavage mechanism, proposed especially for stress-corrosion cracking in systems involving de-alloying at crack tips, is questionable on numerous grounds, and is probably not viable. Rate-controlling processes for environmentally assisted cracking are not well established, except for solid-metal induced embrittlement where surface self-diffusion of embrittling atoms to crack tips controls cracking kinetics. In some systems, adsorption kinetics are probably rate-controlling for liquid-metal embrittlement, hydrogen-environment embrittlement, and stress-corrosion cracking. In other cases, rate-controlling processes could include the rate of anodic or cathodic reactions at and behind crack tips (responsible for producing embrittling

  12. Task Group report to the Assistant Secretary for Environment, Safety and Health on oversight of chemical safety at the Department of Energy. Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    This report presents the results of a preliminary review of chemical safety within the Department of Energy (DOE). The review was conducted by Chemical Safety Oversight Review (CSOR) Teams composed of Office of Environment, Safety and Health (EH) staff members and contractors. The primary objective of the CSOR was to assess, the safety status of DOE chemical operations and identify any significant deficiencies associated with such operations. Significant was defined as any situation posing unacceptable risk, that is, imminent danger or threat to workers, co-located workers, the general public, or the environment, that requires prompt action by EH or the line organizations. A secondary objective of the CSOR was to gather and analyze technical and programmatic information related to chemical safety to be used in conjunction with the longer-range EH Workplace Chemical Accident Risk Review (WCARR) Program. The WCARR Program is part of the ongoing EH oversight of nonnuclear safety at all DOE facilities. `` The program objective is to analyze DOE and industry chemical safety programs and performance and determine the need for additional or improved safety guidance for DOE. During the period June 6, 1992, through July 31, 1992, EH conducted CSORs at five DOE sites. The sites visited were Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 Plant (Y-12), Oak Ridge National Laboratory (ORNL), and Lawrence Livermore National Laboratory (LLNL).

  13. English Learning Adaption under Multi-media and Web-assisted Environment%多媒体网络辅助环境下英语学习适应性研究

    Institute of Scientific and Technical Information of China (English)

    于莹

    2015-01-01

    Learners’ adaption to web-assisted English learning environment is analyzed, mainly from five dimen-sions that include 33 sub-dimensions, i.e.learning motivation, web environment and resources, learning strate-gies, learning abilities and learning contents.The results indicate that learners’ motivation types are mainly in-strumental rather than cultural, interactive or integrative, with certain recreational tendency, that learners are a-daptive to web environment in terms of Internet skills and techniques but lack abilities to utilize English websites offered by English speaking countries and resources in English on websites related to their majors, that self-su-pervision and on-line study planning are both difficult for English learners and learners’ on-line interactive abili-ty is relatively poor, that most learners only practice reading and listening via Internet and are less adaptive to on-line oral or writing tasks.Based on the research, the advice and solutions to the above problems are given for the purpose of improving learners’ adaption under multi-media and web-assisted learning environment.%从学习动机、网络环境和资源、学习策略、学习能力和学习内容5个方面33个子维度,对学习者的网络英语学习适应性进行了调查和分析。研究发现,学习者借助网络方式学习英语的动机类型以工具性为主,呈现出一定的娱乐化倾向,缺乏借助网络实现文化融入和交际目的的动力;对网络环境的技术层面适应度较好,但是对原版英语网站和专业英语网络资源的使用能力不足;缺乏自我监督与网络学习的规划能力,网络互动能力较差;网络学习内容仍以阅读和听力形式为主,对口语和写作训练适应度较差。基于以上研究提出了改善学习者多媒体网络辅助环境下英语学习适应性的建议。

  14. 40 CFR 180.130 - Hydrogen Cyanide; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Hydrogen Cyanide; tolerances for... § 180.130 Hydrogen Cyanide; tolerances for residues. (a) General. A tolerance for residues of the insecticide hydrogen cyanide from postharvest fumigation as a result of application of sodium cyanide is...

  15. Computer Vision Assisted Virtual Reality Calibration

    Science.gov (United States)

    Kim, W.

    1999-01-01

    A computer vision assisted semi-automatic virtual reality (VR) calibration technology has been developed that can accurately match a virtual environment of graphically simulated three-dimensional (3-D) models to the video images of the real task environment.

  16. Computer Vision Assisted Virtual Reality Calibration

    Science.gov (United States)

    Kim, W.

    1999-01-01

    A computer vision assisted semi-automatic virtual reality (VR) calibration technology has been developed that can accurately match a virtual environment of graphically simulated three-dimensional (3-D) models to the video images of the real task environment.

  17. Hydrogen Outgassing from Lithium Hydride

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, L N; Schildbach, M A; Smith, R A; Balazs1, B; McLean II, W

    2006-04-20

    Lithium hydride is a nuclear material with a great affinity for moisture. As a result of exposure to water vapor during machining, transportation, storage and assembly, a corrosion layer (oxide and/or hydroxide) always forms on the surface of lithium hydride resulting in the release of hydrogen gas. Thermodynamically, lithium hydride, lithium oxide and lithium hydroxide are all stable. However, lithium hydroxides formed near the lithium hydride substrate (interface hydroxide) and near the sample/vacuum interface (surface hydroxide) are much less thermally stable than their bulk counterpart. In a dry environment, the interface/surface hydroxides slowly degenerate over many years/decades at room temperature into lithium oxide, releasing water vapor and ultimately hydrogen gas through reaction of the water vapor with the lithium hydride substrate. This outgassing can potentially cause metal hydriding and/or compatibility issues elsewhere in the device. In this chapter, the morphology and the chemistry of the corrosion layer grown on lithium hydride (and in some cases, its isotopic cousin, lithium deuteride) as a result of exposure to moisture are investigated. The hydrogen outgassing processes associated with the formation and subsequent degeneration of this corrosion layer are described. Experimental techniques to measure the hydrogen outgassing kinetics from lithium hydride and methods employing the measured kinetics to predict hydrogen outgassing as a function of time and temperature are presented. Finally, practical procedures to mitigate the problem of hydrogen outgassing from lithium hydride are discussed.

  18. A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-05-11

    Titanium alloy degradation modes are reviewed in relation to their performance in repository environments. General corrosion, localized corrosion, stress corrosion cracking, hydrogen induced cracking, microbially influenced corrosion, and radiation-assisted corrosion of Ti alloys are considered. With respect to the Ti Grade 7 drip shields selected for emplacement in the repository at Yucca Mountain, general corrosion, hydrogen induced cracking, and radiation-assisted corrosion will not lead to failure within the 10,000 year regulatory period; stress corrosion cracking (in the absence of disruptive events) is of no consequence to barrier performance; and localized corrosion and microbially influenced corrosion are not expected to occur. To facilitate the discussion, Ti Grades 2, 5, 7, 9, 11, 12, 16, 17, 18, and 24 are included in this review.

  19. System for the co-production of electricity and hydrogen

    Science.gov (United States)

    Pham, Ai Quoc; Anderson, Brian Lee

    2007-10-02

    Described herein is a system for the co-generation of hydrogen gas and electricity, wherein the proportion of hydrogen to electricity can be adjusted from 0% to 100%. The system integrates fuel cell technology for power generation with fuel-assisted steam-electrolysis. A hydrocarbon fuel, a reformed hydrocarbon fuel, or a partially reformed hydrocarbon fuel can be fed into the system.

  20. Environmentally Assisted Cracking of Nickel Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2004-02-06

    Environmentally Assisted Cracking (EAC) is a general term that includes phenomena such as stress corrosion cracking (SCC), hydrogen embrittlement (HE), sulfide stress cracking (SSC), liquid metal embrittlement (LME), etc. EAC refers to a phenomenon by which a normally ductile metal looses its toughness (e.g. elongation to rupture) when it is subjected to mechanical stresses in presence of a specific corroding environment. For EAC to occur, three affecting factors must be present simultaneously. These include: (1) Mechanical tensile stresses, (2) A susceptible metal microstructure and (3) A specific aggressive environment. If any of these three factors is removed, EAC will not occur. That is, to mitigate the occurrence of EAC, engineers may for example eliminate residual stresses in a component or limit its application to certain chemicals (environment). The term environment not only includes chemical composition of the solution in contact with the component but also other variables such as temperature and applied potential. Nickel alloys are in general more resistant than stainless steels to EAC. For example, austenitic stainless steels (such as S30400) suffer SCC in presence of hot aqueous solutions containing chloride ions. Since chloride ions are ubiquitous in most industrial applications, the use of stressed stainless steels parts is seriously limited. On the other hand, nickel alloys (such as N10276) are practically immune to SCC in presence of hot chloride solutions and therefore an excellent alternative to replace the troubled stainless steels. Nonetheless, nickel alloys are not immune to other types of EAC. There are several environments (such as hot caustic and hot hydrofluoric acid) that may produce embrittlement in nickel alloys (Crum et al, 2000) (Table 1). The conditions where nickel alloys suffer EAC are highly specific and therefore avoidable by the proper design of the industrial components.

  1. Hydrogen Bonds in Excited State Proton Transfer

    Science.gov (United States)

    Horke, D. A.; Watts, H. M.; Smith, A. D.; Jager, E.; Springate, E.; Alexander, O.; Cacho, C.; Chapman, R. T.; Minns, R. S.

    2016-10-01

    Hydrogen bonding interactions between biological chromophores and their surrounding protein and solvent environment significantly affect the photochemical pathways of the chromophore and its biological function. A common first step in the dynamics of these systems is excited state proton transfer between the noncovalently bound molecules, which stabilizes the system against dissociation and principally alters relaxation pathways. Despite such fundamental importance, studying excited state proton transfer across a hydrogen bond has proven difficult, leaving uncertainties about the mechanism. Through time-resolved photoelectron imaging measurements, we demonstrate how the addition of a single hydrogen bond and the opening of an excited state proton transfer channel dramatically changes the outcome of a photochemical reaction, from rapid dissociation in the isolated chromophore to efficient stabilization and ground state recovery in the hydrogen bonded case, and uncover the mechanism of excited state proton transfer at a hydrogen bond, which follows sequential hydrogen and charge transfer processes.

  2. Environmentally assisted cracking in light water reactors.

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, O. K.; Chung, H. M.; Clark, R. W.; Gruber, E. E.; Shack, W. J.; Soppet, W. K.; Strain, R. V.

    2007-11-06

    This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) from January to December 2002. Topics that have been investigated include: (a) environmental effects on fatigue crack initiation in carbon and low-alloy steels and austenitic stainless steels (SSs), (b) irradiation-assisted stress corrosion cracking (IASCC) of austenitic SSs in BWRs, (c) evaluation of causes and mechanisms of irradiation-assisted cracking of austenitic SS in PWRs, and (d) cracking in Ni-alloys and welds. A critical review of the ASME Code fatigue design margins and an assessment of the conservation in the current choice of design margins are presented. The existing fatigue {var_epsilon}-N data have been evaluated to define the effects of key material, loading, and environmental parameters on the fatigue lives of carbon and low-alloy steels and austenitic SSs. Experimental data are presented on the effects of surface roughness on fatigue crack initiation in these materials in air and LWR environments. Crack growth tests were performed in BWR environments on SSs irradiated to 0.9 and 2.0 x 10{sup 21} n x cm{sup -2}. The crack growth rates (CGRs) of the irradiated steels are a factor of {approx}5 higher than the disposition curve proposed in NUREG-0313 for thermally sensitized materials. The CGRs decreased by an order of magnitude in low-dissolved oxygen (DO) environments. Slow-strain-rate tensile (SSRT) tests were conducted in high-purity 289 C water on steels irradiated to {approx}3 dpa. The bulk S content correlated well with the susceptibility to intergranular SCC in 289 C water. The IASCC susceptibility of SSs that contain >0.003 wt. % S increased drastically. bend tests in inert environments at 23 C were conducted on broken pieces of SSRT specimens and on unirradiated specimens of the same materials after hydrogen charging. The results of the tests and a review of other data in the literature

  3. High Pressure Hydrogen Materials Compatibility of Piezoelectric Films

    Energy Technology Data Exchange (ETDEWEB)

    Alvine, Kyle J.; Shutthanandan, V.; Bennett, Wendy D.; Bonham, Charles C.; Skorski, Daniel C.; Pitman, Stan G.; Dahl, Michael E.; Henager, Charles H.

    2010-12-02

    Abstract: Hydrogen is being considered as a next-generation clean burning fuel. However, hydrogen has well known materials issues, including blistering and embrittlement in metals. Piezoelectric materials are used as actuators in hydrogen fuel technology. We present studies of materials compatibility of piezoelectric films in a high pressure hydrogen environment. Absorption of high pressure hydrogen was studied with Elastic Recoil Detection Analysis (ERDA) and Rutherford Back Scattering (RBS) in lead zirconate titanate (PZT) and barium titanate (BTO) thin films. Hydrogen surface degradation in the form of blistering and Pb mixing was also observed.

  4. Hydrogen in metals

    CSIR Research Space (South Africa)

    Carter, TJ

    2001-04-01

    Full Text Available of hydrogen in metals processing and treatment identified, and mechanisms for hydrogen entry into a ferritic surface are discussed. The differences between hydrogen attack of ferritic steels and copper alloys are contrasted, and an unusual case study...

  5. Long-term environmental and socio-economic impact of a hydrogen energy program in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Lutero Carmo de [Uberlandia Univ., Dept. of Mechanical Engineering, Uberlandia, MG (Brazil); Veziroglu, T. Nejat [Miami Univ., Clean Energy Research Inst., Coral Gables, FL (United States)

    2001-07-01

    In this study, a program of electrolytic hydrogen generation for Brazil through the assistance of photovoltaic cell panels is proposed. The generated hydrogen will serve as an energy carrier and will be used in every application where fossil fuels are being used today. Three scenarios have been considered: fast hydrogen introduction, slow hydrogen introduction, and no hydrogen introduction. The results show that hydrogen introduction (1) will increase the energy consumption, (2) will increase the gross national product per capita, (3) will reduce pollution, and (4) will increase the quality of life in Brazil. Fast hydrogen introduction brings the benefits by 20 years earlier. (Author)

  6. Hydrogen heat treatment of hydrogen absorbing materials

    Science.gov (United States)

    Park, Choong-Nyeon

    2000-12-01

    This study introduces the hydrogen heat treatment of hydrogen absorbing materials and its applicability for practical use. This treatment is somewhat different from normal heat treatment because of the interaction between metal atoms and hydrogen. Since hydrogen can be removed very fast by pumping it out the hydrogen-induced new lattice phase which can not be obtained without hydrogen can be preserved in a meta-stable state. A thermodynamic interpretation of the hydrogen heat treatment established previously was reformulated for graphical and analytical methods and applied to Pd-Pt-H and Pd-Ag-H alloy systems and a fair correlation between the calculation and experimental results was shown. The feasibility of applying the thermodynamic interpretation to intermetallic compounds-hydrogen systems was also discussed.

  7. Catalytic membrane reactors based on macroporous silicon for hydrogen production

    OpenAIRE

    Vega Bru, Didac; Hernández Díaz, David; López, E. (Eduardo); Jiménez, Nuria; Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Alcubilla González, Ramón; Llorca Piqué, Jordi

    2010-01-01

    The typology of using hydrogen as an energy carrier and its implementation in portable fuel cells has motivated a considerable research interest in the development of new efficient hydrogen production technologies. Hydrogen storage and manipulation is however a problematic and hazardous issue. Therefore, the low temperature on-site steam reforming of alcohols for hydrogen supply offers a nice solution to safety and storage issues, while providing several environment advantages […] Peer Rev...

  8. Effective hydrogen storage: a strategic chemistry challenge.

    Science.gov (United States)

    David, William I F

    2011-01-01

    This paper gives an overview of the current status and future potential of hydrogen storage from a chemistry perspective and is based on the concluding presentation of the Faraday Discussion 151--Hydrogen Storage Materials. The safe, effective and economical storage of hydrogen is one of the main scientific and technological challenges in the move towards a low-carbon economy. One key sector is transportation where future vehicles will most likely be developed around a balance of battery-electric and hydrogen fuel-cell electric technologies. Although there has been a very significant research effort in solid-state hydrogen storage, high-pressure gas storage combined with conventional metal hydrides is still seen as the current intermediate-term candidate for car manufacturers. Significant issues have arisen in the search for improved solid-state hydrogen storage materials; for example, facile reversibility has been a major challenge for many recently studied complex hydrides while physisorption in porous structures is still restricted to cryogenic temperatures. However, many systems fulfil the majority of necessary criteria for improved hydrogen storage--indeed, the discovery of reversibility in multicomponent hydride systems along with recent chemistry breakthroughs in off-board and solvent-assisted regeneration suggest that the goal of both improved on-board reversible and off-board regenerated hydrogen storage systems can be achieved.

  9. Assisted Living

    Science.gov (United States)

    ... if needs change. Assisted living costs less than nursing home care. It is still fairly expensive. Older people or their families usually pay for it. Health and long-term care insurance policies may cover ...

  10. Revisiting the solar hydrogen alternative

    Energy Technology Data Exchange (ETDEWEB)

    Tomkiewicz, M. [Brooklyn College of CUNY, NY (United States)

    1996-09-01

    Research aimed at the development of technology to advance the solar-hydrogen alternative is per definition mission oriented. The priority that society puts on such research rise and fall with the priorities that we associate with the mission. The mission that we associate with the hydrogen economy is to provide a technological option for an indefinitely sustainable energy and material economies in which society is in equilibrium with its environment. In this paper we try to examine some global aspects of the hydrogen alternative and recommend formulation of a {open_quotes}rational{close_quotes} tax and regulatory system that is based on efforts needed to restore the ecological balance. Such a system, once entered into the price structure of the alternative energy schemes, will be used as a standard to compare energy systems that in turn will serve as a base for prioritization of publicly supported research and development.

  11. Deposition of thin layers of boron nitrides and hydrogenated microcrystalline silicon assisted by high current direct current arc plasma; Deposition assistee par un plasma a arc a haut courant continu de couches minces de Nitrure de Bore et de Silicium microcristallin hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Franz, D. [Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne (Switzerland)

    1999-09-01

    In the frame of this thesis, a high current direct current arc (HCDCA) used for the industrial deposition of diamond, has been adapted to study the deposition of two types of coatings: a) boron nitride, whose cubic phase is similar to diamond, for tribological applications, b) hydrogenated microcrystalline silicon, for applications in the semiconductor fields (flat panel displays, solar cells,...). For the deposition of these coatings, the substrates were placed in the diffusion region of the arc. The substrate heating is mainly due to atomic species recombining on its surface. The deposition temperature, varying from 300 to 900 {sup o}C according to the films deposited, is determined by the substrate position, the arc power and the injected gas fluxes, without the use of any external heating or cooling system. Measurements performed on the arc plasma show that the electronic temperature is around 2 eV (23'000 K) while the gas temperature is lower than 5500 K. Typical electronic densities are in the range of 10{sup 12}-10{sup 1'}3 cm{sup -3}. For the deposition of boron nitride films, different boron precursors were used and a wide parameter range was investigated. The extreme difficulty of synthesising cubic boron nitride films by chemical vapour deposition (CVD) did not allow to stabilize the cubic phase of boron nitride in HCDCA. Coatings resulted in hexagonal or amorphous boron nitride with a chemical composition close to stoichiometric. The presence of hydrogen leads to the deposition of rough and porous films. Negative biasing of the samples, for positive ion bombardment, is commonly used to stabilize the cubic phase. In HCDCA and in our biasing range, only a densification of the films could be observed. A boron nitride deposition plasma study by infrared absorption spectroscopy in a capacitive radio frequency reactor has demonstrated the usefulness of this diagnostic for the understanding of the various chemical reactions which occur in this kind

  12. Hydrogen sulphide.

    Science.gov (United States)

    Guidotti, T L

    1996-10-01

    Hydrogen sulphide (H2S) is the primary chemical hazard in natural gas production in 'sour' gas fields. It is also a hazard in sewage treatment and manure-containment operations, construction in wetlands, pelt processing, certain types of pulp and paper production, and any situation in which organic material decays or inorganic sulphides exist under reducing conditions. H2S dissociates into free sulphide in the circulation. Sulphide binds to many macromolecules, among them cytochrome oxidase. Although this is undoubtedly an important mechanism of toxicity due to H2S, there may be others H2S provides little opportunity for escape at high concentrations because of the olfactory paralysis it causes, the steep exposure-response relationships, and the characteristically sudden loss of consciousness it can cause which is colloquially termed 'knockdown.' Other effects may include mucosal irritation, which is associated at lower concentrations with a keratoconjunctivitis called 'gas eye' and at higher concentrations with risk of pulmonary oedema. Chronic central nervous system sequelae may possibly follow repeated knockdowns: this is controversial and the primary effects of H2S may be confounded by anoxia or head trauma. Treatment is currently empirical, with a combination of nitrite and hyperbaric oxygen preferred. The treatment regimen is not ideal and carries some risk.

  13. Assistive Technology Based on Robotics and Rise in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaoyu; WANG Kaixuan

    2013-01-01

    The concept of assistive technology based on robotics,rehabilitation robot and intelligent assistive devices.Domestic intelligence assistive devices include intelligent prosthetics,intelligent orthotics,intelligent walker,assistive devices for smart home environment control,intelligent life assistive devices; Domestic intelligent rehabilitation robot include upper limb rehabilitation robot,hand rehabilitation robot,lower limb rehabilitation robot,robotic smart wheelchair,intelligent nursing bed,daily care robot,the development trend of intelligent assistive devices and rehabilitation robot.

  14. 13 CFR 302.1 - Environment.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Environment. 302.1 Section 302.1 Business Credit and Assistance ECONOMIC DEVELOPMENT ADMINISTRATION, DEPARTMENT OF COMMERCE GENERAL TERMS AND CONDITIONS FOR INVESTMENT ASSISTANCE § 302.1 Environment. EDA will undertake environmental...

  15. Hydrogen: the future energy carrier.

    Science.gov (United States)

    Züttel, Andreas; Remhof, Arndt; Borgschulte, Andreas; Friedrichs, Oliver

    2010-07-28

    Since the beginning of the twenty-first century the limitations of the fossil age with regard to the continuing growth of energy demand, the peaking mining rate of oil, the growing impact of CO2 emissions on the environment and the dependency of the economy in the industrialized world on the availability of fossil fuels became very obvious. A major change in the energy economy from fossil energy carriers to renewable energy fluxes is necessary. The main challenge is to efficiently convert renewable energy into electricity and the storage of electricity or the production of a synthetic fuel. Hydrogen is produced from water by electricity through an electrolyser. The storage of hydrogen in its molecular or atomic form is a materials challenge. Some hydrides are known to exhibit a hydrogen density comparable to oil; however, these hydrides require a sophisticated storage system. The system energy density is significantly smaller than the energy density of fossil fuels. An interesting alternative to the direct storage of hydrogen are synthetic hydrocarbons produced from hydrogen and CO2 extracted from the atmosphere. They are CO2 neutral and stored like fossil fuels. Conventional combustion engines and turbines can be used in order to convert the stored energy into work and heat.

  16. Non-covalent O$\\cdots$O interactions among isopolyanions using a cis-{MoO2} moiety by the assistance of N-H$\\cdots$O hydrogen bonds

    Indian Academy of Sciences (India)

    T Arumuganathan; A Srinivasa Rao; Samar K Das

    2008-05-01

    An inorganic-organic hybrid material, [2-AmpH]4[Mo8O26] (1) has been isolated by the reaction of Na2MoO4·2H2O with 2-aminopyrimidine (2-Amp) from an acidic aqueous medium. In this low pH synthesis, the organic molecule (2-Amp) gets mono-protonated (2-AmpH+) and acts as the cation in stabilizing the octamolybdate anion in 1. Compound 1 crystallizes in the triclinic space group -1 with = 9.925(3), = 10.020(3), = 10.414(3) Å, = 88.811(4), = 64.907(4), = 89.506(4)°, = 1. An interesting three-dimensional supramolecular structure, having well-defined channels, is formed through N-H$\\cdots$O and C-H$\\cdots$O hydrogen bonds, in which the protonated organic cation plays a significant role. The crystal structure also reveals an unusual cluster-cluster (non-covalent O$\\cdots$O) interaction using cis-(MoO2} moieties of the isopolyanion. N-H$\\cdots$O hydrogen bonds, originated from pyridimidinium cation and isopolyanion, are found to influence to attain such non-covalent O$\\cdots$O interactions among polyoxometalate anions. An interesting helical arrangement, formed from isopolyanion and organic cation, is observed.

  17. Safety distances for hydrogen filling stations

    NARCIS (Netherlands)

    Matthijsen, A J C M; Kooi, E S

    2006-01-01

    In the context of spatial planning the Dutch Ministry of Housing, Spatial Planning and the Environment asked the Centre for External Safety of the National Institute for Public Health and the Environment (RIVM) to advice on safe distances pertaining to hydrogen filling stations. The RIVM made use of

  18. Safety distances for hydrogen filling stations

    NARCIS (Netherlands)

    Matthijsen, A J C M; Kooi, E S

    2006-01-01

    In the context of spatial planning the Dutch Ministry of Housing, Spatial Planning and the Environment asked the Centre for External Safety of the National Institute for Public Health and the Environment (RIVM) to advice on safe distances pertaining to hydrogen filling stations. The RIVM made use of

  19. The solar-hydrogen economy: an analysis

    Science.gov (United States)

    Reynolds, Warren D.

    2007-09-01

    The 20th Century was the age of the Petroleum Economy while the 21st Century is certainly the age of the Solar-Hydrogen Economy. The global Solar-Hydrogen Economy that is now emerging follows a different logic. Under this new economic paradigm, new machines and methods are once again being developed while companies are restructuring. The Petroleum Economy will be briefly explored in relation to oil consumption, Hubbert's curve, and oil reserves with emphasis on the "oil crash". Concerns and criticisms about the Hydrogen Economy will be addressed by debunking some of the "hydrogen myths". There are three major driving factors for the establishment of the Solar-Hydrogen Economy, i.e. the environment, the economy with the coming "oil crash", and national security. The New Energy decentralization pathway has developed many progressive features, e.g., reducing the dependence on oil, reducing the air pollution and CO II. The technical and economic aspects of the various Solar-Hydrogen energy options and combinations will be analyzed. A proposed 24-hour/day 200 MWe solar-hydrogen power plant for the U.S. with selected energy options will be discussed. There are fast emerging Solar Hydrogen energy infrastructures in the U.S., Europe, Japan and China. Some of the major infrastructure projects in the transportation and energy sectors will be discussed. The current and projected growth in the Solar-Hydrogen Economy through 2045 will be given.

  20. A hydrogen ice cube

    NARCIS (Netherlands)

    Schrauwers, A.

    2004-01-01

    Hydrogen is considered to be a highly promising energy carrier. Nonetheless, before hydrogen can become the fuel of choice for the future a number of slight problems will have to be overcome. For example, how can hydrogen be safely stored? Motor vehicles running on hydrogen may be clean in concept

  1. A hydrogen ice cube

    NARCIS (Netherlands)

    Schrauwers, A.

    2004-01-01

    Hydrogen is considered to be a highly promising energy carrier. Nonetheless, before hydrogen can become the fuel of choice for the future a number of slight problems will have to be overcome. For example, how can hydrogen be safely stored? Motor vehicles running on hydrogen may be clean in concept b

  2. Hearing Assistive Technology

    Science.gov (United States)

    ... for the Public / Hearing and Balance Hearing Assistive Technology Hearing Assistive Technology: FM Systems | Infrared Systems | Induction ... Assistive Technology Systems Solutions What are hearing assistive technology systems (HATS)? Hearing assistive technology systems (HATS) are ...

  3. 40 CFR 35.4005 - What is a Technical Assistance Grant?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false What is a Technical Assistance Grant... FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Technical Assistance General § 35.4005 What is a Technical Assistance Grant? A Technical Assistance Grant (TAG) provides money for your group to obtain...

  4. Solar Photovoltaic Hydrogen: The Technologies and Their Place in Our Roadmaps and Energy Economics

    Energy Technology Data Exchange (ETDEWEB)

    Kazmerski, L. L.; Broussard, K.

    2004-08-01

    Future solar photovoltaics-hydrogen systems are discussed in terms of the evolving hydrogen economy. The focus is on distributed hydrogen, relying on the same distributed-energy strengths of solar-photovoltaic electricity in the built environment. Solar-hydrogen residences/buildings, as well as solar parks, are presented. The economics, feasibility, and potential of these approaches are evaluated in terms of roadmap predictions on photovoltaic and hydrogen pathways-and whether solar-hydrogen fit in these strategies and timeframes. Issues with the ''hydrogen future'' are considered, and alternatives to this hydrogen future are examined.

  5. Solar photovoltaic hydrogen: the technologies and their place in our road-maps and energy economics

    Energy Technology Data Exchange (ETDEWEB)

    Kazmerski, L.L. [National Renewable Energy Laboratory, Golden, Colorado (United States); Broussard, K. [Southern Univ., Baton Rouge, LA (United States)

    2004-07-01

    Future solar photovoltaic-hydrogen systems are discussed in terms of the evolving hydrogen economy. The focus is on distributed hydrogen, relying on the same distributed-energy strengths of solar-photovoltaic electricity in the built environment. Solar-hydrogen residences/buildings, as well as solar parks, are presented. The economics, feasibility, and potential of these approaches are evaluated in terms of road-map predictions on photovoltaic and hydrogen pathways and whether solar-hydrogen fit in these strategies and time-frames. Issues with the ''hydrogen future'' are considered, and alternatives to this hydrogen future are examined. (authors)

  6. Influences of gaseous environment on low growth-rate fatigue crack propagation in steels. Annual report No. 1, January 1980. Report No. FPL/R/80/1030

    Energy Technology Data Exchange (ETDEWEB)

    Ritchie, R.O.; Suresh, S.; Toplosky, J.

    1980-01-01

    The influence of gaseous environment is examined on fatigue crack propagation behavior in steels. Specifically, a fully martensitic 300-M ultrahigh strength steel and a fully bainitic 2-1/4Cr-1Mo lower strength steel are investigated in environments of ambient temperature moist air and low pressure dehumidified hydrogen and argon gases over a wide range of growth rates from 10/sup -8/ to 10/sup -2/ mm/cycle, with particular emphasis given to behavior near the crack propagation threshold ..delta..K/sub 0/. It is found that two distinct growth rate regimes exist where hydrogen can markedly accelerate crack propagation rates compared to air, (1) at near-threshold levels below (5 x 10/sup -6/ mm/cycle) and (2) at higher growth rates, typically around 10/sup -5/ mm/cycle above a critical maximum stress intensity K/sub max//sup T/. Hydrogen-assisted crack propagation at higher growth rates is attributed to a hydrogen embrittlement mechanism, with K/sub max//sup T/ nominally equal to K/sub Iscc/ (the sustained load stress corrosion threshold) in high strength steels, and far below K/sub Iscc/ in the strain-rate sensitive lower strength steels. Hydrogen-assisted crack propagation at near-threshold levels is attributed to a new mechanism involving fretting-oxide-induced crack closure generated in moist (or oxygenated) environments. The absence of hydrogen embrittlement mechanisms at near-threshold levels is supported by tests showing that ..delta..K/sub 0/ values in dry gaseous argon are similar to ..delta..K/sub 0/ values in hydrogen. The potential ramifications of these results are examined in detail.

  7. Fatigue of stainless steel in hydrogen

    Science.gov (United States)

    Schuster, G.; Altstetter, C.

    1983-10-01

    The fatigue crack growth rates of two austenitic stainless steel alloys, AISI 301 and 302, were compared in air, argon, and hydrogen environments at atmospheric pressure and room temperature. Under the stresses at the crack tip the austenite in type 301 steel transformed martensitically to a’ to a greater extent than in type 302 steel. The steels were also tested in the cold worked condition under hydrogen or argon. Hydrogen was found to have a deleterious effect on both steels, but the effect was stronger in the unstable than in the stable alloy. Cold work decreased fatigue crack growth rates in argon and hydrogen, but the decrease was less marked in hydrogen than in argon. Metallographic, fractographic, and microhardness surveys in the vicinity of the fatigue crack were used to try to understand the reasons for the observed fatigue behavior.

  8. Thin films of hydrogenated amorphous carbon (a-C:H) obtained through chemical vapor deposition assisted by plasma; Peliculas delgadas de carbono amorfo hidrogenado (a-C:H) obtenidas mediante deposito quimico de vapores asistido por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Mejia H, J.A.; Camps C, E.E.; Escobar A, L.; Romero H, S.; Chirino O, S. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Muhl S, S. [IIM-UNAM, 04510 Mexico D.F. (Mexico)

    2004-07-01

    Films of hydrogenated amorphous carbon (a-C:H) were deposited using one source of microwave plasma with magnetic field (type ECR), using mixtures of H{sub 2}/CH{sub 4} in relationship of 80/20 and 95/05 as precursory gases, with work pressures of 4X10{sup -4} to 6x10{sup -4} Torr and an incident power of the discharge of microwaves with a constant value of 400 W. It was analyzed the influence among the properties of the films, as the deposit rate, the composition and the bonding types, and the deposit conditions, such as the flow rates of the precursory gases and the polarization voltage of the sample holders. (Author)

  9. Isothermal Decomposition of Hydrogen Peroxide Dihydrate

    Science.gov (United States)

    Loeffler, M. J.; Baragiola, R. A.

    2011-01-01

    We present a new method of growing pure solid hydrogen peroxide in an ultra high vacuum environment and apply it to determine thermal stability of the dihydrate compound that forms when water and hydrogen peroxide are mixed at low temperatures. Using infrared spectroscopy and thermogravimetric analysis, we quantified the isothermal decomposition of the metastable dihydrate at 151.6 K. This decomposition occurs by fractional distillation through the preferential sublimation of water, which leads to the formation of pure hydrogen peroxide. The results imply that in an astronomical environment where condensed mixtures of H2O2 and H2O are shielded from radiolytic decomposition and warmed to temperatures where sublimation is significant, highly concentrated or even pure hydrogen peroxide may form.

  10. Estimation of optimal capacity of the module through the demand analysis of refinery hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Young-Seek; Kim, Ho-Jin; Kim, Il-Su [SK energy Institution of Technology, Daejeon (Korea, Republic of)] (and others)

    2006-02-15

    Hydrogen is focused as energy carrier, not an energy source on the rising of problems such as exhaustion of fossil fuel and environment pollution. Thermochemical hydrogen production by nuclear energy has potential to efficiently produce large quantities of hydrogen without producing greenhouse gases. The oil refiners and petro-chemical plant are very large, centralized producers and users of industrial hydrogen, and they a high-potential early market for hydrogen produced by nuclear energy. Therefore, hydrogen market of petro-chemical industry as demand site for nuclear hydrogen was investigated and worked for demand forecast of hydrogen in 2020. Also we suggested possible supply plans of nuclear hydrogen considered regional characteristics. The hydrogen production cost was analyzed and estimated for nuclear hydrogen as well as conventional hydrogen production such as natural gas reforming and coal gasification in various range.

  11. Teaching Assistants.

    Science.gov (United States)

    Feinman, Jay M.

    1991-01-01

    A discussion of teaching assistants (TAs) in the law school looks at the TA's cognitive and affective roles and effective ways to use TAs to reinforce usual forms of learning in the large class; introduce a broadened range of materials, skills, and learning methods; and transform the large class experience. (MSE)

  12. Assistive Devices

    Science.gov (United States)

    ... a number of assistive devices. These are tools, products or types of equipment that help you perform tasks and activities. They may help you move around, see, communicate, eat, or get dressed. Some are high-tech tools, such as computers. Others are much simpler, ...

  13. Hydrogen production by biological processes: a survey of literature

    Energy Technology Data Exchange (ETDEWEB)

    Das, Debabrata [Indian Inst. of Technology, Dept. of Biotechnology, Kharagpur (India); Miami Univ., Clean Energy Research Inst., Coral Gables, FL (United States); Veziroglu, T. Nejat [Miami Univ., Clean Energy Research Inst., Coral Gables, FL (United States)

    2001-07-01

    Hydrogen is the fuel of the future mainly due to its high conversion efficiency, recyclability and nonpolluting nature. Biological hydrogen production processes are found to be more environment friendly and less energy intensive as compared to thermochemical and electrochemical processes. They are mostly controlled by either photosynthetic or fermentative organisms. Till today, more emphasis has been given on the former processes. Nitrogenase and hydrogenase play very important roles. Genetic manipulation of cyanobacteria (hydrogenase negative gene) improves the hydrogen generation. The paper presents a survey of biological hydrogen production processes. The micro-organism and biochemical pathways involved in hydrogen generation processes are presented in some detail. Several developmental works are discussed. Immobilised system is found suitable for the continuous hydrogen production. About 28% of energy can be recovered in the form of hydrogen using sucrose as substrate. Fermentative hydrogen production processes have some edge over the other biological processes. (Author)

  14. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  15. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  16. Bio-assisted synthesis and characterization of nanostructured bismuth (III) sulphide using Clostridium acetobutylicum

    Energy Technology Data Exchange (ETDEWEB)

    Kamaraj, Sathish Kumar; Venkatachalam, Ganesh; Arumugam, Palaniappan; Berchmans, Sheela, E-mail: sheelaberchmans@yahoo.com

    2014-02-14

    Nanostructured bismuth (III) sulphide is synthesized at room temperature using a hydrogen sulphide producing microorganism namely Clostridium acetobutylicum. On contrary to chemical routes involving both the high and room temperature methods, the present experimental procedure involves a bio-assisted approach. This method is free from the usage of toxic and hazardous chemicals making it an environment friendly route. The synthesized bismuth sulphide is characterized using transmission electron microscope (TEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). From our experiments we find that bismuth sulphide produced using this bio-assisted approach exhibits a hexagonal shaped plate-like structures and is stabilized by the extracellular proteins present in the culture medium. - Graphical abstract: A green chemistry approach towards the synthesis of bismuth (III) sulphide nanostructures at room temperature using a hydrogen sulphide producing microorganism namely, Clostridium acetobutylicum is demonstrated. - Highlights: • Environmentally benign (greener) route towards synthesis of Bi{sub 2}S{sub 3} nanostructures. • Bio-assisted synthesis of Bi{sub 2}S{sub 3} at room temperature using Clostridium acetobutylicum. • Extracellular proteins in H{sub 2}S producing microorganism as stabilizer for Bi{sub 2}S{sub 3} NPs. • Hexagonal platelets of Bi{sub 2}S{sub 3} possessing an orthorhombic crystalline structure.

  17. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Kreutz, T.G.; Steinbugler, M. [Princeton Univ., NJ (United States)] [and others

    1996-10-01

    In this report the authors describe results from technical and economic assessments carried out during the past year with support from the USDOE Hydrogen R&D Program. (1) Assessment of technologies for small scale production of hydrogen from natural gas. Because of the cost and logistics of transporting and storing hydrogen, it may be preferable to produce hydrogen at the point of use from more readily available energy carriers such as natural gas or electricity. In this task the authors assess near term technologies for producing hydrogen from natural gas at small scale including steam reforming, partial oxidation and autothermal reforming. (2) Case study of developing a hydrogen vehicle refueling infrastructure in Southern California. Many analysts suggest that the first widespread use of hydrogen energy is likely to be in zero emission vehicles in Southern California. Several hundred thousand zero emission automobiles are projected for the Los Angeles Basin alone by 2010, if mandated levels are implemented. Assuming that hydrogen vehicles capture a significant fraction of this market, a large demand for hydrogen fuel could evolve over the next few decades. Refueling a large number of hydrogen vehicles poses significant challenges. In this task the authors assess near term options for producing and delivering gaseous hydrogen transportation fuel to users in Southern California including: (1) hydrogen produced from natural gas in a large, centralized steam reforming plant, and delivered to refueling stations via liquid hydrogen truck or small scale hydrogen gas pipeline, (2) hydrogen produced at the refueling station via small scale steam reforming of natural gas, (3) hydrogen produced via small scale electrolysis at the refueling station, and (4) hydrogen from low cost chemical industry sources (e.g. excess capacity in refineries which have recently upgraded their hydrogen production capacity, etc.).

  18. Polymers for hydrogen infrastructure and vehicle fuel systems :

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Rachel Reina; Simmons, Kevin L.; San Marchi, Christopher W.

    2013-10-01

    This document addresses polymer materials for use in hydrogen service. Section 1 summarizes the applications of polymers in hydrogen infrastructure and vehicle fuel systems and identifies polymers used in these applications. Section 2 reviews the properties of polymer materials exposed to hydrogen and/or high-pressure environments, using information obtained from published, peer-reviewed literature. The effect of high pressure on physical and mechanical properties of polymers is emphasized in this section along with a summary of hydrogen transport through polymers. Section 3 identifies areas in which fuller characterization is needed in order to assess material suitability for hydrogen service.

  19. Concentration of Hydrogen Peroxide

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  20. Hydrogen in semiconductors

    CERN Document Server

    Pankove, Jacques I

    1991-01-01

    Hydrogen plays an important role in silicon technology, having a profound effect on a wide range of properties. Thus, the study of hydrogen in semiconductors has received much attention from an interdisciplinary assortment of researchers. This sixteen-chapter volume provides a comprehensive review of the field, including a discussion of hydrogenation methods, the use of hydrogen to passivate defects, the use of hydrogen to neutralize deep levels, shallow acceptors and shallow donors in silicon, vibrational spectroscopy, and hydrogen-induced defects in silicon. In addition to this detailed cove

  1. Hydrogen Isotope Exchange Properties of Porous Solids Containing Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    HEUNG, LEUNGK.

    2004-08-18

    Porous solids such as activated alumina, silica and molecular sieves generally contain significant amounts of hydrogen atoms in the form of H2O or OH even at high temperature and low humidity environment. A significant amount of this hydrogen is available for reversible isotopic exchange. This exchange reaction is slow under normal conditions and does not render itself to practical applications. But if the exchange kinetics is improved this reaction has the potential to be used for tritium removal from gas streams or for hydrogen isotopic separation.The use of catalysts to improve the exchange kinetics between hydrogen isotope in the gas phase and that in the solid phase was investigated. Granules of alumina, silica and molecular sieve were coated with platinum or palladium as the catalyst. The granules were packed in a 2-cm diameter column for isotope exchange tests. Gas streams containing different concentrations of deuterium in nitrogen or argon were fed through the protium saturated column. Isotope concentration in column effluent was monitored to generate isotope break-through curves. The curves were analyzed to produce information on the kinetics and capacity of the material. The results showed that all materials tested provided some extent of isotope exchange but some were superior both in kinetics and capacity. This paper will present the test results.

  2. A Sentinel Sensor Network for Hydrogen Sensing

    Directory of Open Access Journals (Sweden)

    Andrew J. Mason

    2003-02-01

    Full Text Available A wireless sensor network is presented for in-situ monitoring of atmospheric hydrogen concentration. The hydrogen sensor network consists of multiple sensor nodes, equipped with titania nanotube hydrogen sensors, distributed throughout the area of interest; each node is both sensor, and data-relay station that enables extended wide area monitoring without a consequent increase of node power and thus node size. The hydrogen sensor is fabricated from a sheet of highly ordered titania nanotubes, made by anodization of a titanium thick film, to which platinum electrodes are connected. The electrical resistance of the hydrogen sensor varies from 245 Ω at 500 ppm hydrogen, to 10.23 kΩ at 0 ppm hydrogen (pure nitrogen environment. The measured resistance is converted to voltage, 0.049 V at 500 ppm to 2.046 V at 0 ppm, by interface circuitry. The microcontroller of the sensor node digitizes the voltage and transmits the digital information, using intermediate nodes as relays, to a host node that downloads measurement data to a computer for display. This paper describes the design and operation of the sensor network, the titania nanotube hydrogen sensors with an apparent low level resolution of approximately 0.05 ppm, and their integration in one widely useful device.

  3. Hydrogen sensing characteristics from carbon nanotube field emissions

    Science.gov (United States)

    Dong, Changkun; Luo, Haijun; Cai, Jianqiu; Wang, Fuquan; Zhao, Yangyang; Li, Detian

    2016-03-01

    An innovative hydrogen sensing concept is demonstrated based on the field emission from multi-walled carbon nanotubes, where the low emission currents rise in proportion to hydrogen partial pressures above 10-9 Torr. Experimental and first principles studies reveal that the sensing mechanism is attributed to the effective work function reduction from dissociative hydrogen chemisorption. The embedded Ni catalyst would assist both the hydrogen dissociation and work function reduction. This technique is promising to build miniature low cost hydrogen sensors for multiple applications. This work is valuable for studies of nanocarbon-gas reaction mechanisms and the work function properties in adsorption related applications, including field emission, hydrogen storage, energy cells, and gas sensing.

  4. Final Scientifc Report - Hydrogen Education State Partnership Project

    Energy Technology Data Exchange (ETDEWEB)

    Leon, Warren

    2012-02-03

    Under the leadership of the Department of Energy Hydrogen and Fuel Cells program, Clean Energy States Alliance (CESA) educated and worked with state leaders to encourage wider deployment of fuel cell and hydrogen technologies. Through outreach to state policymakers, legislative leaders, clean energy funds, energy agencies, and public utility commissions, CESA worked to accomplish the following objectives of this project: 1. Provide information and technical assistance to state policy leaders and state renewable energy programs in the development of effective hydrogen fuel cell programs. 2. Identify and foster hydrogen program best practices. 3. Identify and promote strategic opportunities for states and the Department of Energy (DOE) to advance hydrogen technology deployment through partnerships, collaboration, and targeted activities. Over the three years of this project, CESA, with our partner National Conference of State Legislatures (NCSL), was able to provide credible information on fuel cell policies, finance, and technical assistance to hundreds of state officials and other stakeholders. CESA worked with its membership network to effectively educate state clean energy policymakers, program managers, and decision makers about fuel cell and hydrogen technologies and the efforts by states to advance those technologies. With the assistance of NCSL, CESA gained access to an effective forum for outreach and communication with state legislators from all 50 states on hydrogen issues and policies. This project worked to educate policymakers and stakeholders with the potential to develop and deploy stationary and portable fuel cell technologies.

  5. Molecular structure, heteronuclear resonance assisted hydrogen bond analysis, chemical reactivity and first hyperpolarizability of a novel ethyl-4-{[(2,4-dinitrophenyl)-hydrazono]-ethyl}-3,5-dimethyl-1H-pyrrole-2-carboxylate: a combined DFT and AIM approach.

    Science.gov (United States)

    Singh, R N; Kumar, Amit; Tiwari, R K; Rawat, Poonam; Baboo, Vikas; Verma, Divya

    2012-06-15

    A new ethyl-4-{[(2,4-dinitrophenyl)-hydrazono]-ethyl}-3,5-dimethyl-1H-pyrrole-2-carboxylate (EDPHEDPC) has been synthesized and characterized by FT-IR, (1)H NMR, UV-vis, DART-Mass spectroscopy and elemental analysis. Quantum chemical calculations have been performed by DFT level of theory using B3LYP functional and 6-31G(d,p) as basis set. The (1)H NMR chemical shifts are calculated using gauge including atomic orbitals (GIAO) approach in DMSO as solvent. The time dependent density functional theory (TD-DFT) is used to find the various electronic transitions and their nature within molecule. A combined theoretical and experimental wavenumber analysis confirms the existence of dimer. Topological parameters such as electron density (ρ(BCP)), Laplacian of electron density (nabla(2)ρ(BCP)), kinetic electron energy density (G(BCP)), potential electron density (V(BCP)) and the total electron energy density (H(BCP)) at bond critical points (BCP) have been analyzed by Bader's 'Atoms in molecules' AIM theory in detail. The intermolecular hydrogen bond energy of dimer is calculated as -12.51 kcal/mol using AIM calculations. AIM ellipticity analysis is carried out to confirm the presence of resonance assisted intra and intermolecular hydrogen bonds in dimer. The calculated thermodynamic parameters show that reaction is exothermic and non-spontaneous at room temperature. The local reactivity descriptors such as Fukui functions (f(k)(+), f(k)(-)), local softnesses (s(k)(-), s(k)(+)) and electrophilicity indices (ω(k)(+), ω(k)(-)) analyses are performed to determine the reactive sites within molecule. Nonlinear optical (NLO) behavior of title compound is investigated by the computed value of first hyperpolarizability (β(0)). Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Mechanisms of defect complex formation and environmental-assisted fracture behavior of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, B.R.; Muratov, L.S.; Kang, B.S.J.; Li, K.Z. [West Virginia Univ., Morgantown, WV (United States)

    1997-12-01

    Iron aluminide has excellent corrosion resistance in high-temperature oxidizing-sulfidizing environments; however, there are problems at room and medium temperature with hydrogen embrittlement as related to exposure to moisture. In this research, a coordinated computational modeling/experimental study of mechanisms related to environmental-assisted fracture behavior of selected iron aluminides is being undertaken. The modeling and the experimental work will connect at the level of coordinated understanding of the mechanisms for hydrogen penetration and for loss of strength and susceptibility to fracture. The focus of the modeling component at this point is on the challenging question of accurately predicting the iron vacancy formation energy in Fe{sub 3}A{ell} and the subsequent tendency, if present, for vacancy clustering. The authors have successfully performed, on an ab initio basis, the first calculation of the vacancy formation energy in Fe{sub 3}A{ell}. These calculations include lattice relaxation effects which are quite large. This has significant implications for vacancy clustering effects with consequences to be explored for hydrogen diffusion. The experimental work at this stage has focused on the relationship of the choice and concentration of additives to the improvement of resistance to hydrogen embrittlement and hence to the fracture behavior. For this reason, comparative crack growth tests of FA-186, FA-187, and FA-189 iron aluminides (all with basic composition of Fe-28A{ell}-5Cr, at % with micro-alloying additives of Zr, C or B) under, air, oxygen, or water environment have been performed. These tests showed that the alloys are susceptible to room temperature hydrogen embrittlement in both B2 and DO{sub 3} conditions. Test results indicated that FA-187, and FA-189 are intrinsically more brittle than FA-186.

  7. Tritium/hydrogen barrier development

    Energy Technology Data Exchange (ETDEWEB)

    Hollenberg, G.W.; Simonen, E.P. [Pacific Northwest Lab., Richland, WA (United States); Kalinen, G. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany). International Thermonuclear Experimental Reactor (ITER) Team; Terlain, A. [CEA Centre d`Etudes de Fontenay-aux-Roses, 92 (France). Service de la Corrosion, d`Electrochimie et Chimie des Fluides

    1994-06-01

    A review of hydrogen permeation barriers that can be applied to structural metals used in fusion power plants is presented. Both implanted and chemically available hydrogen isotopes must be controlled in fusion plants. The need for permeation barriers appears strongest in Li17-Pb blanket designs, although barriers also appear necessary for other blanket and coolant systems. Barriers that provide greater than a 1000 fold reduction in the permeation of structural metals are desired. In laboratory experiments, aluminide and titanium ceramic coatings provide permeation reduction factors, PRFS, from 1000 to over 100,000 with a wide range of scatter. The rate-controlling mechanism for hydrogen permeation through these barriers may be related to the number and type of defects in the barriers. Although these barriers appear robust and resistant to liquid metal corrosion, irradiation tests which simulate blanket environments result in very low PRFs in comparison to laboratory experiments, i.e., <150. It is anticipated from fundamental research activities that the REID enhancement of hydrogen diffusion in oxides may contribute to the lower permeation reduction factors during in-reactor experiments.

  8. Dynamics of hydrogen in hydrogenated amorphous silicon

    Indian Academy of Sciences (India)

    Ranber Singh; S Prakash

    2003-07-01

    The problem of hydrogen diffusion in hydrogenated amorphous silicon (a-Si:H) is studied semiclassically. It is found that the local hydrogen concentration fluctuations-induced extra potential wells, if intense enough, lead to the localized electronic states in a-Si:H. These localized states are metastable. The trapping of electrons and holes in these states leads to the electrical degradation of the material. These states also act as recombination centers for photo-generated carriers (electrons and holes) which in turn may excite a hydrogen atom from a nearby Si–H bond and breaks the weak (strained) Si–Si bond thereby apparently enhancing the hydrogen diffusion and increasing the light-induced dangling bonds.

  9. Hydrogen transport membranes

    Science.gov (United States)

    Mundschau, Michael V.

    2005-05-31

    Composite hydrogen transport membranes, which are used for extraction of hydrogen from gas mixtures are provided. Methods are described for supporting metals and metal alloys which have high hydrogen permeability, but which are either too thin to be self supporting, too weak to resist differential pressures across the membrane, or which become embrittled by hydrogen. Support materials are chosen to be lattice matched to the metals and metal alloys. Preferred metals with high permeability for hydrogen include vanadium, niobium, tantalum, zirconium, palladium, and alloys thereof. Hydrogen-permeable membranes include those in which the pores of a porous support matrix are blocked by hydrogen-permeable metals and metal alloys, those in which the pores of a porous metal matrix are blocked with materials which make the membrane impervious to gases other than hydrogen, and cermets fabricated by sintering powders of metals with powders of lattice-matched ceramic.

  10. Hydrogen production by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Chaudhuri Surabhi

    2005-12-01

    Full Text Available Abstract The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical, Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source.

  11. Handbook of hydrogen energy

    CERN Document Server

    Sherif, SA; Stefanakos, EK; Steinfeld, Aldo

    2014-01-01

    ""This book provides an excellent overview of the hydrogen economy and a thorough and comprehensive presentation of hydrogen production and storage methods.""-Scott E. Grasman, Rochester Institute of Technology, New York, USA

  12. Hydrogen Technologies Safety Guide

    Energy Technology Data Exchange (ETDEWEB)

    Rivkin, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Burgess, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Buttner, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-01-01

    The purpose of this guide is to provide basic background information on hydrogen technologies. It is intended to provide project developers, code officials, and other interested parties the background information to be able to put hydrogen safety in context. For example, code officials reviewing permit applications for hydrogen projects will get an understanding of the industrial history of hydrogen, basic safety concerns, and safety requirements.

  13. Final Report: Metal Perhydrides for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, J-Y.; Shi, S.; Hackney, S.; Swenson, D.; Hu, Y.

    2011-07-26

    H molecule contains one hydrogen atom because the valence of a Li ion is +1. One MgH2 molecule contains two hydrogen atoms because the valence of a Mg ion is +2. In metal perhydrides, a molecule could contain more hydrogen atoms than expected based on the metal valance, i.e. LiH1+n and MgH2+n (n is equal to or greater than 1). When n is sufficiently high, there will be plenty of hydrogen storage capacity to meet future requirements. The existence of hydrogen clusters, Hn+ (n = 5, 7, 9, 11, 13, 15) and transition metal ion-hydrogen clusters, M+(H2)n (n = 1-6), such as Sc(H2)n+, Co(H2)n+, etc., have assisted the development of this concept. Clusters are not stable species. However, their existence stimulates our approach on using electric charges to enhance the hydrogen adsorption in a hydrogen storage system in this study. The experimental and modeling work to verify it are reported here. Experimental work included the generation of cold hydrogen plasma through a microwave approach, synthesis of sorbent materials, design and construction of lab devices, and the determination of hydrogen adsorption capacities on various sorbent materials under various electric field potentials and various temperatures. The results consistently show that electric potential enhances the adsorption of hydrogen on sorbents. NiO, MgO, activated carbon, MOF, and MOF and platinum coated activated carbon are some of the materials studied. Enhancements up to a few hundred percents have been found. In general, the enhancement increases with the electrical potential, the pressure applied, and the temperature lowered. Theoretical modeling of the hydrogen adsorption on the sorbents under the electric potential has been investigated with the density functional theory (DFT) approach. It was found that the interaction energy between hydrogen and sorbent is increased remarkably when an electric field is applied. This increase of binding energy offers a potential solution for DOE when looking for a compromise

  14. LaNi5-Assisted Hydrogenation of MgNi2 in the Hybrid Structures of La1.09Mg1.91Ni9D9.5 and La0.91Mg2.09Ni9D9.4

    Directory of Open Access Journals (Sweden)

    Roman V. Denys

    2015-04-01

    Full Text Available This work focused on the high pressure PCT and in situ neutron powder diffraction studies of the LaMg2Ni9-H2 (D2 system at pressures up to 1,000 bar. LaMg2Ni9 alloy was prepared by a powder metallurgy route from the LaNi9 alloy precursor and Mg powder. Two La3−xMgxNi9 samples with slightly different La/Mg ratios were studied, La1.1Mg1.9Ni9 (sample 1 and La0.9Mg2.1Ni9 (sample 2. In situ neutron powder diffraction studies of the La1.09Mg1.91Ni9D9.5 (1 and La0.91Mg2.09Ni9D9.4 (2 deuterides were performed at 25 bar D2 (1 and 918 bar D2 (2. The hydrogenation properties of the (1 and (2 are dramatically different from those for LaNi3. The Mg-containing intermetallics reversibly form hydrides with DHdes = 24.0 kJ/molH2 and an equilibrium pressure of H2 desorption of 18 bar at 20 °C (La1.09Mg1.91Ni9. A pronounced hysteresis of H2 absorption and desorption, ~100 bar, is observed. The studies showed that LaNi5-assisted hydrogenation of MgNi2 in the LaMg2Ni9 hybrid structure takes place. In the La1.09Mg1.91Ni9D9.5 (1 and La0.91Mg2.09Ni9D9.4 (2 (a = 5.263/5.212; c = 25.803/25.71 Å D atoms are accommodated in both Laves and CaCu5-type slabs. In the LaNi5 CaCu5-type layer, D atoms fill three types of interstices; a deformed octahedron [La2Ni4], and [La(Mg2Ni2] and [Ni4] tetrahedra. The overall chemical compositions can be presented as LaNi5H5.6/5.0 + 2*MgNi2H1.95/2.2 showing that the hydrogenation of the MgNi2 slab proceeds at mild H2/D2 pressure of just 20 bar. A partial filling by D of the four types of the tetrahedral interstices in the MgNi2 slab takes place, including [MgNi3] and [Mg2Ni2] tetrahedra.

  15. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

    Vigeholm, B.; Kjøller, John; Larsen, Bent

    1980-01-01

    The reaction of hydrogen with commercially pure magnesium powder (above 99.7%) was investigated in the temperature range 250–400 °C. Hydrogen is readily sorbed above the dissociation pressure. During the initial exposure the magnesium powder sorbs hydrogen slowly below 400 °C but during the second...

  16. Biological hydrogen photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Y. [Univ. of Miami, FL (United States)

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  17. Sensitive hydrogen leak detector

    Science.gov (United States)

    Myneni, Ganapati Rao

    1999-01-01

    A sensitive hydrogen leak detector system using passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor.

  18. Hydrogen separation process

    Science.gov (United States)

    Mundschau, Michael [Longmont, CO; Xie, Xiaobing [Foster City, CA; Evenson, IV, Carl; Grimmer, Paul [Longmont, CO; Wright, Harold [Longmont, CO

    2011-05-24

    A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to a hydrogen separation membrane system comprising a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to an integrated water gas shift/hydrogen separation membrane system wherein the hydrogen separation membrane system comprises a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for pretreating a membrane, comprising: heating the membrane to a desired operating temperature and desired feed pressure in a flow of inert gas for a sufficient time to cause the membrane to mechanically deform; decreasing the feed pressure to approximately ambient pressure; and optionally, flowing an oxidizing agent across the membrane before, during, or after deformation of the membrane. A method of supporting a hydrogen separation membrane system comprising selecting a hydrogen separation membrane system comprising one or more catalyst outer layers deposited on a hydrogen transport membrane layer and sealing the hydrogen separation membrane system to a porous support.

  19. Neutral Hydrogen in Galaxy Groups

    CERN Document Server

    McKay, N P F; Brough, S; Forbes, D A; Barnes, D G

    2002-01-01

    We present preliminary results from a study of the neutral hydrogen (HI) properties of an X-ray selected sample of nearby loose galaxy groups. This forms part of a multi-wavelength investigation (X-ray, optical and radio) of the formation and evolution of galaxies within a group environment. Some initial findings of an ATNF Parkes Multibeam wide-area neutral hydrogen imaging survey of 17 nearby galaxy groups include two new, potentially isolated clouds of HI in the NGC 1052 and NGC 5044 groups and significant amounts of HI within the group virial radii of groups NGC 3557 and IC 1459 - two groups with complex X-ray structures that suggest they may still be in the act of virialisation. Here we present ATCA high-resolution synthesis-imaging follow-up observations of the distribution and kinematics of HI in these four groups.

  20. Materials for hydrogen storage

    Directory of Open Access Journals (Sweden)

    Andreas Züttel

    2003-09-01

    The goal is to pack hydrogen as close as possible, i.e. to reach the highest volumetric density by using as little additional material as possible. Hydrogen storage implies the reduction of an enormous volume of hydrogen gas. At ambient temperature and atmospheric pressure, 1 kg of the gas has a volume of 11 m3. To increase hydrogen density, work must either be applied to compress the gas, the temperature decreased below the critical temperature, or the repulsion reduced by the interaction of hydrogen with another material.

  1. Solar Hydrogen Reaching Maturity

    Directory of Open Access Journals (Sweden)

    Rongé Jan

    2015-09-01

    Full Text Available Increasingly vast research efforts are devoted to the development of materials and processes for solar hydrogen production by light-driven dissociation of water into oxygen and hydrogen. Storage of solar energy in chemical bonds resolves the issues associated with the intermittent nature of sunlight, by decoupling energy generation and consumption. This paper investigates recent advances and prospects in solar hydrogen processes that are reaching market readiness. Future energy scenarios involving solar hydrogen are proposed and a case is made for systems producing hydrogen from water vapor present in air, supported by advanced modeling.

  2. Composite Metal-hydrogen Electrodes for Metal-Hydrogen Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ruckman, M W; Wiesmann, H; Strongin, M; Young, K; Fetcenko, M

    1997-04-01

    The purpose of this project is to develop and conduct a feasibility study of metallic thin films (multilayered and alloy composition) produced by advanced sputtering techniques for use as anodes in Ni-metal hydrogen batteries. The anodes could be incorporated in thin film solid state Ni-metal hydrogen batteries that would be deposited as distinct anode, electrolyte and cathode layers in thin film devices. The materials could also be incorporated in secondary consumer batteries (i.e. type AF(4/3 or 4/5)) which use electrodes in the form of tapes. The project was based on pioneering studies of hydrogen uptake by ultra-thin Pd-capped metal-hydrogen ratios exceeding and fast hydrogen charging and Nb films, these studies suggested that materials with those of commercially available metal hydride materials discharging kinetics could be produced. The project initially concentrated on gas phase and electrochemical studies of Pd-capped niobium films in laboratory-scale NiMH cells. This extended the pioneering work to the wet electrochemical environment of NiMH batteries and exploited advanced synchrotron radiation techniques not available during the earlier work to conduct in-situ studies of such materials during hydrogen charging and discharging. Although batteries with fast charging kinetics and hydrogen-metal ratios approaching unity could be fabricated, it was found that oxidation, cracking and corrosion in aqueous solutions made pure Nb films-and multiiayers poor candidates for battery application. The project emphasis shifted to alloy films based on known elemental materials used for NiMH batteries. Although commercial NiMH anode materials contain many metals, it was found that 0.24 µm thick sputtered Zr-Ni films cycled at least 50 times with charging efficiencies exceeding 95% and [H]/[M] ratios of 0.7-1.0. Multilayered or thicker Zr-Ni films could be candidates for a thin film NiMH battery that may have practical applications as an integrated power source for

  3. Low Cost Nuclear Thermal Rocket Cermet Fuel Element Environment Testing

    Science.gov (United States)

    Bradley, D. E.; Mireles, O. R.; Hickman, R. R.

    2011-01-01

    Deep space missions with large payloads require high specific impulse and relatively high thrust to achieve mission goals in reasonable time frames.1,2 Conventional storable propellants produce average specific impulse. Nuclear thermal rockets capable of producing high specific impulse are proposed. Nuclear thermal rockets employ heat produced by fission reaction to heat and therefore accelerate hydrogen, which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000 K), and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited.3 The primary concern is the mechanical failure of fuel elements that employ high-melting-point metals, ceramics, or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. The purpose of the testing is to obtain data to assess the properties of the non-nuclear support materials, as-fabricated, and determine their ability to survive and maintain thermal performance in a prototypical NTR reactor environment of exposure to hydrogen at very high temperatures. The fission process of the planned fissile material and the resulting heating performance is well known and does not therefore require that active fissile material be integrated in this testing. A small-scale test bed designed to heat fuel element samples via non-contact radio frequency heating and expose samples to hydrogen is being developed to assist in optimal material and manufacturing process selection without employing fissile material. This paper details the test bed design and results of testing conducted to date.

  4. Final Report: Metal Perhydrides for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, J-Y.; Shi, S.; Hackney, S.; Swenson, D.; Hu, Y.

    2011-07-26

    H molecule contains one hydrogen atom because the valence of a Li ion is +1. One MgH2 molecule contains two hydrogen atoms because the valence of a Mg ion is +2. In metal perhydrides, a molecule could contain more hydrogen atoms than expected based on the metal valance, i.e. LiH1+n and MgH2+n (n is equal to or greater than 1). When n is sufficiently high, there will be plenty of hydrogen storage capacity to meet future requirements. The existence of hydrogen clusters, Hn+ (n = 5, 7, 9, 11, 13, 15) and transition metal ion-hydrogen clusters, M+(H2)n (n = 1-6), such as Sc(H2)n+, Co(H2)n+, etc., have assisted the development of this concept. Clusters are not stable species. However, their existence stimulates our approach on using electric charges to enhance the hydrogen adsorption in a hydrogen storage system in this study. The experimental and modeling work to verify it are reported here. Experimental work included the generation of cold hydrogen plasma through a microwave approach, synthesis of sorbent materials, design and construction of lab devices, and the determination of hydrogen adsorption capacities on various sorbent materials under various electric field potentials and various temperatures. The results consistently show that electric potential enhances the adsorption of hydrogen on sorbents. NiO, MgO, activated carbon, MOF, and MOF and platinum coated activated carbon are some of the materials studied. Enhancements up to a few hundred percents have been found. In general, the enhancement increases with the electrical potential, the pressure applied, and the temperature lowered. Theoretical modeling of the hydrogen adsorption on the sorbents under the electric potential has been investigated with the density functional theory (DFT) approach. It was found that the interaction energy between hydrogen and sorbent is increased remarkably when an electric field is applied. This increase of binding energy offers a potential solution for DOE when looking for a compromise

  5. Hydrogen energy assessment

    Energy Technology Data Exchange (ETDEWEB)

    Salzano, F J; Braun, C [eds.

    1977-09-01

    The purpose of this assessment is to define the near term and long term prospects for the use of hydrogen as an energy delivery medium. Possible applications of hydrogen are defined along with the associated technologies required for implementation. A major focus in the near term is on industrial uses of hydrogen for special applications. The major source of hydrogen in the near term is expected to be from coal, with hydrogen from electric sources supplying a smaller fraction. A number of potential applications for hydrogen in the long term are identified and the level of demand estimated. The results of a cost benefit study for R and D work on coal gasification to hydrogen and electrolytic production of hydrogen are presented in order to aid in defining approximate levels of R and D funding. A considerable amount of data is presented on the cost of producing hydrogen from various energy resources. A key conclusion of the study is that in time hydrogen is likely to play a role in the energy system; however, hydrogen is not yet competitive for most applications when compared to the cost of energy from petroleum and natural gas.

  6. Hydrogen energy for beginners

    CERN Document Server

    2013-01-01

    This book highlights the outstanding role of hydrogen in energy processes, where it is the most functional element due to its unique peculiarities that are highlighted and emphasized in the book. The first half of the book covers the great natural hydrogen processes in biology, chemistry, and physics, showing that hydrogen is a trend that can unite all natural sciences. The second half of the book is devoted to the technological hydrogen processes that are under research and development with the aim to create the infrastructure for hydrogen energetics. The book describes the main features of hydrogen that make it inalienable player in processes such as fusion, photosynthesis, and metabolism. It also covers the methods of hydrogen production and storage, highlighting at the same time the exclusive importance of nanotechnologies in those processes.

  7. Photobiological hydrogen production.

    Science.gov (United States)

    Asada, Y; Miyake, J

    1999-01-01

    The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase via cyanobacterial ferredoxin was demonstrated in the presence of light. Genetic transformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum was successful; the active enzyme was expressed in PCC7942. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Coculture of Rhodobacter and Clostriudium was applied for hydrogen production from glucose. A mutant strain of Rhodobacter sphaeroides RV whose light-harvesting proteins were altered was obtained by UV irradiation. Hydrogen productivity by the mutant was improved when irradiated with monochromatic light of some wavelengths. The development of photobioreactors for hydrogen production is also reviewed.

  8. Capacity retention in hydrogen storage alloys

    Science.gov (United States)

    Anani, A.; Visintin, A.; Srinivasan, S.; Appleby, A. J.; Reilly, J. J.; Johnson, J. R.

    1992-01-01

    Results of our examination of the properties of several candidate materials for hydrogen storage electrodes and their relation to the decrease in H-storage capacity upon open-circuit storage over time are reported. In some of the alloy samples examined to date, only about 10 percent of the hydrogen capacity was lost upon storage for 20 days, while in others, this number was as high as 30 percent for the same period of time. This loss in capacity is attributed to two separate mechanisms: (1) hydrogen desorbed from the electrode due to pressure differences between the cell and the electrode sample; and (2) chemical and/or electrochemical degradation of the alloy electrode upon exposure to the cell environment. The former process is a direct consequence of the equilibrium dissociation pressure of the hydride alloy phase and the partial pressure of hydrogen in the hydride phase in equilibrium with that in the electrolyte environment, while the latter is related to the stability of the alloy phase in the cell environment. Comparison of the equilibrium gas-phase dissociation pressures of these alloys indicate that reversible loss of hydrogen capacity is higher in alloys with P(eqm) greater than 1 atm than in those with P(eqm) less than 1 atm.

  9. Low Cost Hydrogen Production Platform

    Energy Technology Data Exchange (ETDEWEB)

    Timothy M. Aaron, Jerome T. Jankowiak

    2009-10-16

    A technology and design evaluation was carried out for the development of a turnkey hydrogen production system in the range of 2.4 - 12 kg/h of hydrogen. The design is based on existing SMR technology and existing chemical processes and technologies to meet the design objectives. Consequently, the system design consists of a steam methane reformer, PSA system for hydrogen purification, natural gas compression, steam generation and all components and heat exchangers required for the production of hydrogen. The focus of the program is on packaging, system integration and an overall step change in the cost of capital required for the production of hydrogen at small scale. To assist in this effort, subcontractors were brought in to evaluate the design concepts and to assist in meeting the overall goals of the program. Praxair supplied the overall system and process design and the subcontractors were used to evaluate the components and system from a manufacturing and overall design optimization viewpoint. Design for manufacturing and assembly (DFMA) techniques, computer models and laboratory/full-scale testing of components were utilized to optimize the design during all phases of the design development. Early in the program evaluation, a review of existing Praxair hydrogen facilities showed that over 50% of the installed cost of a SMR based hydrogen plant is associated with the high temperature components (reformer, shift, steam generation, and various high temperature heat exchange). The main effort of the initial phase of the program was to develop an integrated high temperature component for these related functions. Initially, six independent concepts were developed and the processes were modeled to determine overall feasibility. The six concepts were eventually narrowed down to the highest potential concept. A US patent was awarded in February 2009 for the Praxair integrated high temperature component design. A risk analysis of the high temperature component was

  10. Low Cost Hydrogen Production Platform

    Energy Technology Data Exchange (ETDEWEB)

    Timothy M. Aaron, Jerome T. Jankowiak

    2009-10-16

    A technology and design evaluation was carried out for the development of a turnkey hydrogen production system in the range of 2.4 - 12 kg/h of hydrogen. The design is based on existing SMR technology and existing chemical processes and technologies to meet the design objectives. Consequently, the system design consists of a steam methane reformer, PSA system for hydrogen purification, natural gas compression, steam generation and all components and heat exchangers required for the production of hydrogen. The focus of the program is on packaging, system integration and an overall step change in the cost of capital required for the production of hydrogen at small scale. To assist in this effort, subcontractors were brought in to evaluate the design concepts and to assist in meeting the overall goals of the program. Praxair supplied the overall system and process design and the subcontractors were used to evaluate the components and system from a manufacturing and overall design optimization viewpoint. Design for manufacturing and assembly (DFMA) techniques, computer models and laboratory/full-scale testing of components were utilized to optimize the design during all phases of the design development. Early in the program evaluation, a review of existing Praxair hydrogen facilities showed that over 50% of the installed cost of a SMR based hydrogen plant is associated with the high temperature components (reformer, shift, steam generation, and various high temperature heat exchange). The main effort of the initial phase of the program was to develop an integrated high temperature component for these related functions. Initially, six independent concepts were developed and the processes were modeled to determine overall feasibility. The six concepts were eventually narrowed down to the highest potential concept. A US patent was awarded in February 2009 for the Praxair integrated high temperature component design. A risk analysis of the high temperature component was

  11. A Smart Kitchen for Ambient Assisted Living

    OpenAIRE

    Rubén Blasco; Álvaro Marco; Roberto Casas; Diego Cirujano; Richard Picking

    2014-01-01

    The kitchen environment is one of the scenarios in the home where users can benefit from Ambient Assisted Living (AAL) applications. Moreover, it is the place where old people suffer from most domestic injuries. This paper presents a novel design, implementation and assessment of a Smart Kitchen which provides Ambient Assisted Living services; a smart environment that increases elderly and disabled people’s autonomy in their kitchen-related activities through context and user awareness, appr...

  12. Hydrogen Fluoride in High-mass Star-forming Regions

    NARCIS (Netherlands)

    Emprechtinger, M.; Monje, R. R.; van der Tak, F. F. S.; van der Wiel, M. H. D.; Lis, D. C.; Neufeld, D.; Phillips, T. G.; Ceccarelli, C.

    2012-01-01

    Hydrogen fluoride (HF) has been established to be an excellent tracer of molecular hydrogen in diffuse clouds. In denser environments, however, the HF abundance has been shown to be approximately two orders of magnitude lower. We present Herschel/HIFI observations of HF J = 1-0 toward two high-mass

  13. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  14. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  15. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Steinbugler, M.; Kreutz, T. [Princeton Univ., NJ (United States). Center for Energy and Environmental Studies

    1998-08-01

    In this progress report (covering the period May 1997--May 1998), the authors summarize results from ongoing technical and economic assessments of hydrogen energy systems. Generally, the goal of their research is to illuminate possible pathways leading from present hydrogen markets and technologies toward wide scale use of hydrogen as an energy carrier, highlighting important technologies for RD and D. Over the past year they worked on three projects. From May 1997--November 1997, the authors completed an assessment of hydrogen as a fuel for fuel cell vehicles, as compared to methanol and gasoline. Two other studies were begun in November 1997 and are scheduled for completion in September 1998. The authors are carrying out an assessment of potential supplies and demands for hydrogen energy in the New York City/New Jersey area. The goal of this study is to provide useful data and suggest possible implementation strategies for the New York City/ New Jersey area, as the Hydrogen Program plans demonstrations of hydrogen vehicles and refueling infrastructure. The authors are assessing the implications of CO{sub 2} sequestration for hydrogen energy systems. The goals of this work are (a) to understand the implications of CO{sub 2} sequestration for hydrogen energy system design; (b) to understand the conditions under which CO{sub 2} sequestration might become economically viable; and (c) to understand design issues for future low-CO{sub 2} emitting hydrogen energy systems based on fossil fuels.

  16. Proceedings of the 14. world hydrogen energy conference 2002 : The hydrogen planet. CD-ROM ed.

    Energy Technology Data Exchange (ETDEWEB)

    Venter, R.D.; Bose, T.K. [Quebec Univ., Trois-Rivieres, PQ (Canada). Institut de recherche sur l' hydrogene; Veziroglu, N. [International Association for Hydrogen Energy, Coral Gables, FL (United States)] (eds.)

    2002-07-01

    Hydrogen has often been named as the ultimate fuel because it can be generated from a variety of renewable and non-renewable fuels and its direct conversion to electricity in fuel cells is efficient and results in no emissions other than water vapour. The opportunities and issues associated with the use of hydrogen as the energy carrier of the future were presented at this conference which addressed all aspects of hydrogen and fuel cell development including hydrogen production, storage, hydrogen-fuelled internal combustion engines, hydrogen infrastructure, economics, and the environment. Hydrogen is currently used as a chemical feedstock and a space fuel, but it is receiving considerable attention for bring renewable energy into the transportation and power generation sectors with little or no environmental impact at the point of end use. Canada leads the way in innovative ideas for a hydrogen infrastructure, one of the most challenging tasks for the transportation sector along with hydrogen storage. Major vehicle manufacturers have announced that they will have hydrogen-fueled cars and buses on the market beginning in 2003 and 2004. Solid oxide fuel cells will be used for generating electricity with efficiencies of 70 per cent, and proton exchange membrane (PEM) and other fuel cells are being tested for residential power supply with efficiencies of 85 per cent. The conference included an industrial exposition which demonstrated the latest developments in hydrogen and fuel cell research. More than 300 papers were presented at various oral and poster sessions, of which 172 papers have been indexed separately for inclusion in the database.

  17. Nanodiamond for hydrogen storage: temperature-dependent hydrogenation and charge-induced dehydrogenation.

    Science.gov (United States)

    Lai, Lin; Barnard, Amanda S

    2012-02-21

    Carbon-based hydrogen storage materials are one of hottest research topics in materials science. Although the majority of studies focus on highly porous loosely bound systems, these systems have various limitations including use at elevated temperature. Here we propose, based on computer simulations, that diamond nanoparticles may provide a new promising high temperature candidate with a moderate storage capacity, but good potential for recyclability. The hydrogenation of nanodiamonds is found to be easily achieved, in agreement with experiments, though we find the stability of hydrogenation is dependent on the morphology of nanodiamonds and surrounding environment. Hydrogenation is thermodynamically favourable even at high temperature in pure hydrogen, ammonia, and methane gas reservoirs, whereas water vapour can help to reduce the energy barrier for desorption. The greatest challenge in using this material is the breaking of the strong covalent C-H bonds, and we have identified that the spontaneous release of atomic hydrogen may be achieved through charging of hydrogenated nanodiamonds. If the degree of induced charge is properly controlled, the integrity of the host nanodiamond is maintained, which indicates that an efficient and recyclable approach for hydrogen release may be possible.

  18. MICROWAVE-EXPEDITED OLEFIN EPOXIDATION OVER HYDROTALCITES USING HYDROGEN PEROXIDE AND ACETONITRILE

    Science.gov (United States)

    An efficient microwave-assisted expoxidation of olefins is described over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile. This general and selective protocol is extremely fast and is applicable to a wide variety of subtrates.

  19. Hydrogen Fuelling Stations

    DEFF Research Database (Denmark)

    Rothuizen, Erasmus Damgaard

    This thesis concerns hydrogen fuelling stations from an overall system perspective. The study investigates thermodynamics and energy consumption of hydrogen fuelling stations for fuelling vehicles for personal transportation. For the study a library concerning the components in a hydrogen fuelling...... station has been developed in Dymola. The models include the fuelling protocol (J2601) for hydrogen vehicles made by Society of Automotive Engineers (SAE) and the thermodynamic property library CoolProp is used for retrieving state point. The components in the hydrogen fuelling library are building up....... A system consisting of one high pressure storage tank is used to investigate the thermodynamics of fuelling a hydrogen vehicle. The results show that the decisive parameter for how the fuelling proceeds is the pressure loss in the vehicle. The single tank fuelling system is compared to a cascade fuelling...

  20. Scandinavian hydrogen highway partnership

    Energy Technology Data Exchange (ETDEWEB)

    Sloth, M.; Hansen, J. [H2 Logic A/S, Herning (Denmark); Wennike, F. [Hydrogen Link Denmark Association, Ringkoebing (Denmark)

    2009-07-01

    The Scandinavian Hydrogen Highway Partnership (SHHP) was launched in an effort to build hydrogen filling stations in Scandinavian countries by 2012 in order to enable hydrogen powered vehicles to operate and refuel when needed. Three hydrogen refueling stations are currently in operation in Scandinavia to fuel a fleet of 15 hydrogen-fuelled cars. It is anticipated that by the end of 2009, there will be 14 hydrogen refueling stations and more than 70 vehicles in operation. Beyond 2012, the number of filling stations and vehicles is expected to increase significantly through large scale demonstration, where SHHP aims to attract funding from the European Union. The current activities of SHHP are co-funded by national and regional authorities. The SHHP network is funded by Nordic Energy Research.

  1. Hydrogen storage container

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John; Feng, Zhili; Zhang, Wei

    2017-02-07

    An apparatus and system is described for storing high-pressure fluids such as hydrogen. An inner tank and pre-stressed concrete pressure vessel share the structural and/or pressure load on the inner tank. The system and apparatus provide a high performance and low cost container while mitigating hydrogen embrittlement of the metal tank. System is useful for distributing hydrogen to a power grid or to a vehicle refueling station.

  2. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Steinbugler, M.; Dennis, E. [Princeton Univ., NJ (United States)] [and others

    1995-09-01

    For several years, researchers at Princeton University`s Center for Energy and Environmental Studies have carried out technical and economic assessments of hydrogen energy systems. Initially, we focussed on the long term potential of renewable hydrogen. More recently we have explored how a transition to renewable hydrogen might begin. The goal of our current work is to identify promising strategies leading from near term hydrogen markets and technologies toward eventual large scale use of renewable hydrogen as an energy carrier. Our approach has been to assess the entire hydrogen energy system from production through end-use considering technical performance, economics, infrastructure and environmental issues. This work is part of the systems analysis activity of the DOE Hydrogen Program. In this paper we first summarize the results of three tasks which were completed during the past year under NREL Contract No. XR-11265-2: in Task 1, we carried out assessments of near term options for supplying hydrogen transportation fuel from natural gas; in Task 2, we assessed the feasibility of using the existing natural gas system with hydrogen and hydrogen blends; and in Task 3, we carried out a study of PEM fuel cells for residential cogeneration applications, a market which might have less stringent cost requirements than transportation. We then give preliminary results for two other tasks which are ongoing under DOE Contract No. DE-FG04-94AL85803: In Task 1 we are assessing the technical options for low cost small scale production of hydrogen from natural gas, considering (a) steam reforming, (b) partial oxidation and (c) autothermal reforming, and in Task 2 we are assessing potential markets for hydrogen in Southern California.

  3. Hydrogen production from banyan leaves using an atmospheric-pressure microwave plasma reactor.

    Science.gov (United States)

    Lin, Yuan-Chung; Wu, Tzi-Yi; Jhang, Syu-Ruei; Yang, Po-Ming; Hsiao, Yi-Hsing

    2014-06-01

    Growth of the hydrogen market has motivated increased study of hydrogen production. Understanding how biomass is converted to hydrogen gas can help in evaluating opportunities for reducing the environmental impact of petroleum-based fuels. The microwave power used in the reaction is found to be proportional to the rate of production of hydrogen gas, mass of hydrogen gas produced per gram of banyan leaves consumed, and amount of hydrogen gas formed with respect to the H-atom content of banyan leaves decomposed. Increase the microwave power levels results in an increase of H2 and decrease of CO2 concentrations in the gaseous products. This finding may possibly be ascribed to the water-gas shift reaction. These results will help to expand our knowledge concerning banyan leaves and hydrogen yield on the basis of microwave-assisted pyrolysis, which will improve the design of hydrogen production technologies.

  4. The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs

    Energy Technology Data Exchange (ETDEWEB)

    Committee on Alternatives and Strategies for Future Hydrogen Production and Use

    2004-08-31

    The announcement of a hydrogen fuel initiative in the President’s 2003 State of the Union speech substantially increased interest in the potential for hydrogen to play a major role in the nation’s long-term energy future. Prior to that event, DOE asked the National Research Council to examine key technical issues about the hydrogen economy to assist in the development of its hydrogen R&D program. Included in the assessment were the current state of technology; future cost estimates; CO2 emissions; distribution, storage, and end use considerations; and the DOE RD&D program. The report provides an assessment of hydrogen as a fuel in the nation’s future energy economy and describes a number of important challenges that must be overcome if it is to make a major energy contribution. Topics covered include the hydrogen end-use technologies, transportation, hydrogen production technologies, and transition issues for hydrogen in vehicles.

  5. Hydrogen Production Cost Estimate Using Biomass Gasification: Independent Review

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, M.

    2011-10-01

    This independent review is the conclusion arrived at from data collection, document reviews, interviews and deliberation from December 2010 through April 2011 and the technical potential of Hydrogen Production Cost Estimate Using Biomass Gasification. The Panel reviewed the current H2A case (Version 2.12, Case 01D) for hydrogen production via biomass gasification and identified four principal components of hydrogen levelized cost: CapEx; feedstock costs; project financing structure; efficiency/hydrogen yield. The panel reexamined the assumptions around these components and arrived at new estimates and approaches that better reflect the current technology and business environments.

  6. Hydrogen Production Cost Estimate Using Biomass Gasification: Independent Review

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-10-01

    This independent review is the conclusion arrived at from data collection, document reviews, interviews and deliberation from December 2010 through April 2011 and the technical potential of Hydrogen Production Cost Estimate Using Biomass Gasification. The Panel reviewed the current H2A case (Version 2.12, Case 01D) for hydrogen production via biomass gasification and identified four principal components of hydrogen levelized cost: CapEx; feedstock costs; project financing structure; efficiency/hydrogen yield. The panel reexamined the assumptions around these components and arrived at new estimates and approaches that better reflect the current technology and business environments.

  7. Hydrogen-bromine fuel cell advance component development

    Science.gov (United States)

    Charleston, Joann; Reed, James

    1988-01-01

    Advanced cell component development is performed by NASA Lewis to achieve improved performance and longer life for the hydrogen-bromine fuel cells system. The state-of-the-art hydrogen-bromine system utilizes the solid polymer electrolyte (SPE) technology, similar to the SPE technology developed for the hydrogen-oxygen fuel cell system. These studies are directed at exploring the potential for this system by assessing and evaluating various types of materials for cell parts and electrode materials for Bromine-hydrogen bromine environment and fabricating experimental membrane/electrode-catalysts by chemical deposition.

  8. Liquid hydrogen in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yasumi, S. [Iwatani Corp., Osaka (Japan). Dept. of Overseas Business Development

    2009-07-01

    Japan's Iwatani Corporation has focused its attention on hydrogen as the ultimate energy source in future. Unlike the United States, hydrogen use and delivery in liquid form is extremely limited in the European Union and in Japan. Iwatani Corporation broke through industry stereotypes by creating and building Hydro Edge Co. Ltd., Japan's largest liquid hydrogen plant. It was established in 2006 as a joint venture between Iwatani and Kansai Electric Power Group in Osaka. Hydro Edge is Japan's first combined liquid hydrogen and ASU plant, and is fully operational. Liquid oxygen, liquid nitrogen and liquid argon are separated from air using the cryogenic energy of liquefied natural gas fuel that is used for power generation. Liquid hydrogen is produced efficiently and simultaneously using liquid nitrogen. Approximately 12 times as much hydrogen in liquid form can be transported and supplied as pressurized hydrogen gas. This technology is a significant step forward in the dissemination and expansion of hydrogen in a hydrogen-based economy.

  9. Triethylammonium hydrogen chloranilate

    Directory of Open Access Journals (Sweden)

    Kazuma Gotoh

    2010-12-01

    Full Text Available In the crystal structure of the title compound (systematic name: triethylammonium 2,5-dichloro-4-hydroxy-3,6-dioxocyclohexa-1,4-dien-1-olate, C6H16N+·C6HCl2O4−, two hydrogen chloranilate anions are connected by a pair of bifurcated O—H...O hydrogen bonds into a dimeric unit. The triethylammonium cations are linked on both sides of the dimer via bifurcated N—H...O hydrogen bonds into a centrosymmetric 2:2 aggregate. The 2:2 aggregates are further linked by intermolecular C—H...O hydrogen bonds.

  10. 40 CFR 5.435 - Employment assistance to students.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Employment assistance to students. 5... to students. (a) Assistance by recipient in making available outside employment. A recipient that assists any agency, organization, or person in making employment available to any of its students:...

  11. Electrochemical hydrogen Storage Systems

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Digby Macdonald

    2010-08-09

    As the global need for energy increases, scientists and engineers have found a possible solution by using hydrogen to power our world. Although hydrogen can be combusted as a fuel, it is considered an energy carrier for use in fuel cells wherein it is consumed (oxidized) without the production of greenhouse gases and produces electrical energy with high efficiency. Chemical storage of hydrogen involves release of hydrogen in a controlled manner from materials in which the hydrogen is covalently bound. Sodium borohydride and aminoborane are two materials given consideration as chemical hydrogen storage materials by the US Department of Energy. A very significant barrier to adoption of these materials as hydrogen carriers is their regeneration from 'spent fuel,' i.e., the material remaining after discharge of hydrogen. The U.S. Department of Energy (DOE) formed a Center of Excellence for Chemical Hydrogen Storage, and this work stems from that project. The DOE has identified boron hydrides as being the main compounds of interest as hydrogen storage materials. The various boron hydrides are then oxidized to release their hydrogen, thereby forming a 'spent fuel' in the form of a lower boron hydride or even a boron oxide. The ultimate goal of this project is to take the oxidized boron hydrides as the spent fuel and hydrogenate them back to their original form so they can be used again as a fuel. Thus this research is essentially a boron hydride recycling project. In this report, research directed at regeneration of sodium borohydride and aminoborane is described. For sodium borohydride, electrochemical reduction of boric acid and sodium metaborate (representing spent fuel) in alkaline, aqueous solution has been investigated. Similarly to literature reports (primarily patents), a variety of cathode materials were tried in these experiments. Additionally, approaches directed at overcoming electrostatic repulsion of borate anion from the cathode, not

  12. 40 CFR 415.420 - Applicability; description of the hydrogen cyanide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... hydrogen cyanide production subcategory. 415.420 Section 415.420 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Cyanide Production Subcategory § 415.420 Applicability; description of the hydrogen cyanide production subcategory. This subpart applies to discharges to waters of the United States...

  13. 40 CFR 415.90 - Applicability; description of the hydrogen peroxide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... hydrogen peroxide production subcategory. 415.90 Section 415.90 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Hydrogen Peroxide Production Subcategory § 415.90 Applicability; description of the hydrogen peroxide production subcategory. The provisions of this subpart are applicable to...

  14. 40 CFR 180.1197 - Hydrogen peroxide; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Hydrogen peroxide; exemption from the... Exemptions From Tolerances § 180.1197 Hydrogen peroxide; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of hydrogen peroxide in or on...

  15. Enhancing hydrogen spillover and storage

    Science.gov (United States)

    Yang, Ralph T.; Li, Yingwel; Lachawiec, Jr., Anthony J.

    2011-05-31

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonification as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  16. Enhancing hydrogen spillover and storage

    Science.gov (United States)

    Yang, Ralph T; Li, Yingwei; Lachawiec, Jr., Anthony J

    2013-02-12

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonication as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  17. Combination moisture and hydrogen getter

    Science.gov (United States)

    Harrah, L.A.; Mead, K.E.; Smith, H.M.

    1983-09-20

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (1) a solid acetylenic compound and (2) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  18. Diagnostic experimental results on the hydrogen embrittlement of austenitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Gavriljuk, V.G.; Shivanyuk, V.N.; Foct, J

    2003-03-14

    Three main available hypotheses of hydrogen embrittlement are analysed in relation to austenitic steels based on the studies of the hydrogen effect on the interatomic bonds, phase transformations and microplastic behaviour. It is shown that hydrogen increases the concentration of free electrons, i.e. enhances the metallic character of atomic interactions, although such a decrease in the interatomic bonding cannot be a reason for brittleness and rather assists an increased plasticity. The hypothesis of the critical role of the hydrogen-induced {epsilon} martensite was tested in the experiment with the hydrogen-charged Si-containing austenitic steel. Both the fraction of the {epsilon} martensite and resistance to hydrogen embrittlement were increased due to Si alloying, which is at variance with the pseudo-hydride hypothesis. The hydrogen-caused early start of the microplastic deformation and an increased mobility of dislocations, which are usually not observed in the common mechanical tests, are revealed by the measurements of the strain-dependent internal friction, which is consistent with the hypothesis of the hydrogen-enhanced localised plasticity. An influence of alloying elements on the enthalpy E{sub H} of hydrogen migration in austenitic steels is studied using the temperature-dependent internal friction and a correlation is found between the values of E{sub H} and hydrogen-caused decrease in plasticity. A mechanism for the transition from the hydrogen-caused microplasticity to the apparent macrobrittle fracture is proposed based on the similarity of the fracture of hydrogenated austenitic steels to that of high nitrogen steels.

  19. Intelligent assistive robots recent advances in assistive robotics for everyday activities

    CERN Document Server

    Moreno, Juan; Kong, Kyoungchul; Amirat, Yacine

    2015-01-01

    This book deals with the growing challenges of using assistive robots in our everyday activities along with providing intelligent assistive services. The presented applications concern mainly healthcare and wellness such as helping elderly people, assisting dependent persons, habitat monitoring in smart environments, well-being, security, etc. These applications reveal also new challenges regarding control theory, mechanical design, mechatronics, portability, acceptability, scalability, security, etc.  

  20. Piezoelectric Bimorph Cantilever for Vibration-Producing-Hydrogen

    Directory of Open Access Journals (Sweden)

    Guangming Cheng

    2012-12-01

    Full Text Available A device composed of a piezoelectric bimorph cantilever and a water electrolysis device was fabricated to realize piezoelectrochemical hydrogen production. The obvious output of the hydrogen and oxygen through application of a mechanical vibration of ~0.07 N and ~46.2 Hz was observed. This method provides a cost-effective, recyclable, environment-friendly and simple way to directly split water for hydrogen fuels by scavenging mechanical waste energy forms such as noise or traffic vibration in the environment.