1/12-scale physical modeling experiments in support of tank 241-SY- 101 hydrogen mitigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fort, J.A.; Bamberger, J.A.; Bates, J.M.

1993-01-01

Hanford tank 241-SY-101 is a 75-ft-dia double-shell tank that contains approximately 1.1 M gal of radioactive fuel reprocessing waste. Core samples have shown that the tank contents are separated into two main layers, a article laden supernatant liquid at the top of the tank and a more dense slurry on the bottom. Two additional layers may be present, one being a potentially thick sludge lying beneath the slurry at the bottom of the tank and the other being the crust that has formed on the surface of the supernatant liquid. The supernatant is more commonly referred to as the convectivemore » layer and the slurry as the non-convective layer. Accumulation of gas (partly hydrogen) in the non-convective layer is suspected to be the key mechanism behind the gas burp phenomena, and several mitigation schemes are being developed to encourage a more uniform gas release rate (Benegas 1992). To support the full-scale hydraulic mitigation test, scaled experiments were performed to satisfy two objectives: 1. provide an experimental database for numerical- model validation; 2. establish operating parameter values required to mobilize the settled solids and maintain the solids in suspension.« less

1/12-scale physical modeling experiments in support of tank 241-SY- 101 hydrogen mitigation. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fort, J.A.; Bamberger, J.A.; Bates, J.M.

1993-01-01

Hanford tank 241-SY-101 is a 75-ft-dia double-shell tank that contains approximately 1.1 M gal of radioactive fuel reprocessing waste. Core samples have shown that the tank contents are separated into two main layers, a article laden supernatant liquid at the top of the tank and a more dense slurry on the bottom. Two additional layers may be present, one being a potentially thick sludge lying beneath the slurry at the bottom of the tank and the other being the crust that has formed on the surface of the supernatant liquid. The supernatant is more commonly referred to as the convectivemore » layer and the slurry as the non-convective layer. Accumulation of gas (partly hydrogen) in the non-convective layer is suspected to be the key mechanism behind the gas burp phenomena, and several mitigation schemes are being developed to encourage a more uniform gas release rate (Benegas 1992). To support the full-scale hydraulic mitigation test, scaled experiments were performed to satisfy two objectives: 1. provide an experimental database for numerical- model validation; 2. establish operating parameter values required to mobilize the settled solids and maintain the solids in suspension.« less

On fast solid-body rotation of the solar core and differential (liquid-like) rotation of the solar surface

NASA Astrophysics Data System (ADS)

Pashitskii, E. A.

2017-07-01

On the basis of a two-component (two-fluid) hydrodynamic model, it is shown that the probable phenomenon of solar core rotation with a velocity higher than the average velocity of global rotation of the Sun, discovered by the SOHO mission, can be related to fast solid-body rotation of the light hydrogen component of the solar plasma, which is caused by thermonuclear fusion of hydrogen into helium inside the hot dense solar core. Thermonuclear fusion of four protons into a helium nucleus (α-particle) creates a large free specific volume per unit particle due to the large difference between the densities of the solar plasma and nuclear matter. As a result, an efficient volumetric sink of one of the components of the solar substance—hydrogen—forms inside the solar core. Therefore, a steady-state radial proton flux converging to the center should exist inside the Sun, which maintains a constant concentration of hydrogen as it burns out in the solar core. It is demonstrated that such a converging flux of hydrogen plasma with the radial velocity v r ( r) = -β r creates a convective, v r ∂ v φ/∂ r, and a local Coriolis, v r v φ/ r,φ nonlinear hydrodynamic forces in the solar plasma, rotating with the azimuthal velocity v φ. In the absence of dissipation, these forces should cause an exponential growth of the solid-body rotation velocity of the hydrogen component inside the solar core. However, friction between the hydrogen and helium components of the solar plasma due to Coulomb collisions of protons with α-particles results in a steady-state regime of rotation of the hydrogen component in the solar core with an angular velocity substantially exceeding the global rotational velocity of the Sun. It is suggested that the observed differential (liquid-like) rotation of the visible surface of the Sun (photosphere) with the maximum angular velocity at the equator is caused by sold-body rotation of the solar plasma in the radiation zone and strong turbulence in the tachocline layer, where the turbulent viscosity reaches its maximum value at the equator. There, the tachocline layer exerts the most efficient drag on the less dense outer layers of the solar plasma, which are slowed down due to the interaction with the ambient space plasma (solar wind).

Oxygen-free atomic layer deposition of indium sulfide

DOEpatents

Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

2016-07-05

A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

Superior Electrical Conductivity in Hydrogenated Layered Ternary Chalcogenide Nanosheets for Flexible All-Solid-State Supercapacitors.

PubMed

Hu, Xin; Shao, Wei; Hang, Xudong; Zhang, Xiaodong; Zhu, Wenguang; Xie, Yi

2016-05-04

As the properties of ultrathin two-dimensional (2D) crystals are strongly related to their electronic structures, more and more attempts were carried out to tune their electronic structures to meet the high standards for the construction of next-generation smart electronics. Herein, for the first time, we show that the conductive nature of layered ternary chalcogenide with formula of Cu2 WS4 can be switched from semiconducting to metallic by hydrogen incorporation, accompanied by a high increase in electrical conductivity. In detail, the room-temperature electrical conductivity of hydrogenated-Cu2 WS4 nanosheet film was almost 10(10) times higher than that of pristine bulk sample with a value of about 2.9×10(4)  S m(-1) , which is among the best values for conductive 2D nanosheets. In addition, the metallicity in the hydrogenated-Cu2 WS4 is robust and can be retained under high-temperature treatment. The fabricated all-solid-state flexible supercapacitor based on the hydrogenated-Cu2 WS4 nanosheet film shows promising electrochemical performances with capacitance of 583.3 F cm(-3) at a current density of 0.31 A cm(-3) . This work not only offers a prototype material for the study of electronic structure regulation in 2D crystals, but also paves the way in searching for highly conductive electrodes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Si substrates texturing and vapor-solid-solid Si nanowhiskers growth using pure hydrogen as source gas

NASA Astrophysics Data System (ADS)

Nordmark, H.; Nagayoshi, H.; Matsumoto, N.; Nishimura, S.; Terashima, K.; Marioara, C. D.; Walmsley, J. C.; Holmestad, R.; Ulyashin, A.

2009-02-01

Scanning and transmission electron microscopies have been used to study silicon substrate texturing and whisker growth on Si substrates using pure hydrogen source gas in a tungsten hot filament reactor. Substrate texturing, in the nanometer to micrometer range of mono- and as-cut multicrystalline silicon, was observed after deposition of WSi2 particles that acted as a mask for subsequent hydrogen radical etching. Simultaneous Si whisker growth was observed for long residence time of the source gas and low H2 flow rate with high pressure. The whiskers formed via vapor-solid-solid growth, in which the deposited WSi2 particles acted as catalysts for a subsequent metal-induced layer exchange process well below the eutectic temperature. In this process, SiHx species, formed by substrate etching by the H radicals, diffuse through the metal particles. This leads to growth of crystalline Si whiskers via metal-induced solid-phase crystallization. Transmission electron microscopy, electron diffraction, and x-ray energy dispersive spectroscopy were used to study the WSi2 particles and the structure of the Si substrates in detail. It has been established that the whiskers are partly crystalline and partly amorphous, consisting of pure Si with WSi2 particles on their tips as well as sometimes being incorporated into their structure.

Surface structure and electrochemical characteristics of Ti-V-Cr bcc-type solid solution alloys sintered with Ni

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuji, Yoichiro; Yamamoto, Osamu; Matsuda, Hiromu

2000-07-01

Ti-V-Cr bcc-type solid solution alloys can absorb a large amount of hydrogen and be applied to active materials of the negative electrode in Ni-MH batteries. However, because of the insolubility of Ni into these alloys, the electrochemical characteristics like discharge capacity and cycle life were poor. In order to increase the discharge capacity of hydrogen absorbing alloy electrodes, Ti-V-Cr bcc-type alloy powders were sintered with Ni in order to form Ni contained surface layer on the alloy surface. As sintering temperature rose up, the surface composition changed from TiNi to Ti{sub 2}Ni. TiNi surface layer showed better electrochemical characteristics. Formore » the Ni adding method, Ni electroless plating was preferred because of good adhesion. As a result of optimized conditions, a discharge capacity of 570 mAh/g and an improvement of cycle life were achieved.« less

Phase transition detection by surface photo charge effect in liquid crystals

NASA Astrophysics Data System (ADS)

Ivanov, O.; Petrov, M.; Naradikian, H.; Perez-Diaz, J. L.

2018-05-01

The surface photo charge effect (SPCE) was applied for the first time at structure and phase transitions study of hydrogen bonded in dimer liquid crystals (HBDLCs). Due to the high sensitivity of this method, besides first-order phase transitions, characteristic for the p,n-octyloxibenzoic acids (8OBA), an order transition was definitely detected within the nematic range. We state that the SPCE, arising at the solid-HBDLCs interface due to the double electrical layer, is invariably concomitant with solid surface-liquid interfaces, and indicates that the changes of the characteristics of this layer, under incident optical irradiation, induce surface charge rearrangement and alternating potential difference. A mechanism of induction of the SPCE at the interface of solid surface-anisotropic liquids is proposed. We also indicate that this mechanism can be adapted for solid surface-isotropic liquid interface, including colloids (milk) and fog (aerosols)-condensed medium.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gil, D.M.; Osiry, H.; Pomiro, F.

The hydrogen bond and π-π stacking are two non-covalent interactions able to support cooperative magnetic ordering between paramagnetic centers. This contribution reports the crystal structure and related magnetic properties for VO[Fe(CN){sub 5}NO]·2H{sub 2}O, which has a layered structure. This solid crystallizes with an orthorhombic unit cell, in the Pna2{sub 1} space group, with cell parameters a=14.1804(2), b=10.4935(1), c=7.1722(8) Å and four molecules per unit cell (Z=4). Its crystal structure was solved and refined from powder X-ray diffraction data. Neighboring layers remain linked through a network of hydrogen bonds involving a water molecule coordinated to the axial position for the Vmore » atom and the unbridged axial NO and CN ligands. An uncoordinated water molecule is found forming a triple bridge between these last two ligands and the coordinated water molecule. The magnetic measurements, recorded down to 2 K, shows a ferromagnetic interaction between V atoms located at neighboring layers, with a Curie-Weiss constant of 3.14 K. Such ferromagnetic behavior was interpreted as resulting from a superexchange interaction through the network of strong OH····O{sub H2O}, OH····N{sub CN}, and OH····O{sub NO} hydrogen bonds that connects neighboring layers. The interaction within the layer must be of antiferromagnetic nature and it was detected close to 2 K. - Graphical abstract: Coordination environment for the metals in vanadyl (II) nitroprusside dihydrate. Display Omitted - Highlights: • Crystal structure of vanadyl nitroprusside dehydrate. • Network of hydrogen bonds. • Magnetic interactions through a network of hydrogen bonds. • Layered transition metal nitroprussides.« less

Solid-State Water Electrolysis with an Alkaline Membrane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leng, YJ; Chen, G; Mendoza, AJ

2012-06-06

We report high-performance, durable alkaline membrane water electrolysis in a solid-state cell. An anion exchange membrane (AEM) and catalyst layer ionomer for hydroxide ion conduction were used without the addition of liquid electrolyte. At 50 degrees C, an AEM electrolysis cell using iridium oxide as the anode catalyst and Pt black as the cathode catalyst exhibited a current density of 399 mA/cm(2) at 1.80 V. We found that the durability of the AEM-based electrolysis cell could be improved by incorporating a highly durable ionomer in the catalyst layer and optimizing the water feed configuration. We demonstrated an AEM-based electrolysis cellmore » with a lifetime of > 535 h. These first-time results of water electrolysis in a solid-state membrane cell are promising for low-cost, scalable hydrogen production.« less

Chemical Conversion of Anhydrous Hydrogen Fluoride for Safe Disposal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blake, Thomas A.; Brauer, Carolyn S.; Bachmann, William J.

A procedure for the safe conversion of a small (~ 1 gram) quantity of anhydrous hydrogen fluoride to calcium fluoride is described. The purpose of the conversion is to put the toxic, corrosive, gaseous compound into a chemical form that is a less toxic solid (calcium fluoride) and easier to dispose of. The hydrogen fluoride, which was contained in a 50 cc metal sample cylinder, was drawn by a small mechanical vacuum pump through an all-metal gas manifold and into a metal trap containing alternating layers of calcium oxide powder and Teflon turnings. The anhydrous hydrogen fluoride reacts with themore » calcium oxide to produce calcium fluoride and water vapor. Because some of the calcium oxide powder was drawn out of the trap and into the vacuum tubing, it was not possible to quantify the amount of anhydrous hydrogen fluoride converted to calcium fluoride. However, it was noted that there was a temperature rise in the trap when the gas was flowing through it, and no HF gas was detected at the vacuum pump exhaust at this time using a colorimetric Dräger tube. The trap was sealed and disposed of as solid chemical waste.« less

Ionic liquids for metal extraction from chalcopyrite: solid, liquid and gas phase studies.

PubMed

Kuzmina, O; Symianakis, E; Godfrey, D; Albrecht, T; Welton, T

2017-08-16

We studied leaching of Cu and Fe from naturally occurring chalcopyrite ore using aqueous solutions of ionic liquids (ILs) based on imidazolium and ethylammonium cations and hydrogensulfate, nitrate, acetate or dicyanamide anions. Liquid, solid and gas phases of the leaching systems were characterised. We have shown that nonoxidative leaching is greatly dependant not only on temperature and pH, but on the anion species of the IL. Solutions of 1-butylimidazolium hydrogen sulfate exhibited the best leaching performance among hydrogen sulphate ILs. We have suggested that the formation of an oxide layer in some ILs may be responsible for a reduced leaching ability. The analysis of the gas phase showed the production of CO 2 and CS 2 in all leached samples. Our results suggested that the CS 2 produced upon leaching could be responsible for decreasing the sulfur, but not oxide, layer on the surface of chalcopyrite samples and therefore more efficient leaching. This is the first study, to our knowledge, to provide a systematic comparison of the leaching performance of ILs composed of different anions and cations and without added oxidants.

Enhanced Hydrogen Storage Properties and Reversibility of LiBH4 Confined in Two-Dimensional Ti3C2.

PubMed

Zang, Lei; Sun, Weiyi; Liu, Song; Huang, Yike; Yuan, Huatang; Tao, Zhanliang; Wang, Yijing

2018-05-30

LiBH 4 is of particular interest as one of the most promising materials for solid-state hydrogen storage. Herein, LiBH 4 is confined into a novel two-dimensional layered Ti 3 C 2 MXene through a facile impregnation method for the first time to improve its hydrogen storage performance. The initial desorption temperature of LiBH 4 is significantly reduced, and the de-/rehydrogenation kinetics are remarkably enhanced. It is found that the initial desorption temperature of LiBH 4 @2Ti 3 C 2 hybrid decreases to 172.6 °C and releases 9.6 wt % hydrogen at 380 °C within 1 h, whereas pristine LiBH 4 only releases 3.2 wt % hydrogen under identical conditions. More importantly, the dehydrogenated products can partially rehydrogenate at 300 °C and under 95 bar H 2 . The nanoconfined effect caused by unique layered structure of Ti 3 C 2 can hinder the particles growth and agglomeration of LiBH 4 . Meanwhile, Ti 3 C 2 could possess superior effect to destabilize LiBH 4 . The synergetic effect of destabilization and nanoconfinement contributes to the remarkably lowered desorption temperature and improved de-/rehydrogenation kinetics.

Joint Experimental and Computational 17O and 1H Solid State NMR Study of Ba 2In 2O 4(OH) 2 Structure and Dynamics

DOE PAGES

Dervisoglu, Riza; Middlemiss, Derek S.; Blanc, Frederic; ...

2015-05-01

Here, a structural characterization of the hydrated form of the brownmillerite-type phase Ba 2In 2O 5, Ba 2In 2O 4(OH) 2, is reported using experimental multinuclear NMR spectroscopy and density functional theory (DFT) energy and GIPAW NMR calculations. When the oxygen ions from H 2O fill the inherent O vacancies of the brownmillerite structure, one of the water protons remains in the same layer (O3) while the second proton is located in the neighboring layer (O2) in sites with partial occupancies, as previously demonstrated by Jayaraman et al. (Solid State Ionics 2004, 170, 25–32) using X-ray and neutron studies. Calculationsmore » of possible proton arrangements within the partially occupied layer of Ba 2In 2O 4(OH) 2 yield a set of low energy structures; GIPAW NMR calculations on these configurations yield 1H and 17O chemical shifts and peak intensity ratios, which are then used to help assign the experimental MAS NMR spectra. Three distinct 1H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer. The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. 1H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C. Three distinct types of oxygen atoms are evident from the DFT GIPAW calculations bare oxygens (O), oxygens directly bonded to a proton (H-donor O), and oxygen ions that are hydrogen bonded to a proton (H-acceptor O). The 17O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by 1H– 17O double resonance experiments.« less

Joint Experimental and Computational 17O and 1H Solid State NMR Study of Ba2In2O4(OH)2 Structure and Dynamics.

PubMed

Dervişoğlu, Rıza; Middlemiss, Derek S; Blanc, Frédéric; Lee, Yueh-Lin; Morgan, Dane; Grey, Clare P

2015-06-09

A structural characterization of the hydrated form of the brownmillerite-type phase Ba 2 In 2 O 5 , Ba 2 In 2 O 4 (OH) 2 , is reported using experimental multinuclear NMR spectroscopy and density functional theory (DFT) energy and GIPAW NMR calculations. When the oxygen ions from H 2 O fill the inherent O vacancies of the brownmillerite structure, one of the water protons remains in the same layer (O3) while the second proton is located in the neighboring layer (O2) in sites with partial occupancies, as previously demonstrated by Jayaraman et al. (Solid State Ionics2004, 170, 25-32) using X-ray and neutron studies. Calculations of possible proton arrangements within the partially occupied layer of Ba 2 In 2 O 4 (OH) 2 yield a set of low energy structures; GIPAW NMR calculations on these configurations yield 1 H and 17 O chemical shifts and peak intensity ratios, which are then used to help assign the experimental MAS NMR spectra. Three distinct 1 H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer. The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. 1 H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C. Three distinct types of oxygen atoms are evident from the DFT GIPAW calculations bare oxygens (O), oxygens directly bonded to a proton (H-donor O), and oxygen ions that are hydrogen bonded to a proton (H-acceptor O). The 17 O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by 1 H- 17 O double resonance experiments.

Joint Experimental and Computational 17O and 1H Solid State NMR Study of Ba2In2O4(OH)2 Structure and Dynamics

PubMed Central

2015-01-01

A structural characterization of the hydrated form of the brownmillerite-type phase Ba2In2O5, Ba2In2O4(OH)2, is reported using experimental multinuclear NMR spectroscopy and density functional theory (DFT) energy and GIPAW NMR calculations. When the oxygen ions from H2O fill the inherent O vacancies of the brownmillerite structure, one of the water protons remains in the same layer (O3) while the second proton is located in the neighboring layer (O2) in sites with partial occupancies, as previously demonstrated by Jayaraman et al. (Solid State Ionics2004, 170, 25−32) using X-ray and neutron studies. Calculations of possible proton arrangements within the partially occupied layer of Ba2In2O4(OH)2 yield a set of low energy structures; GIPAW NMR calculations on these configurations yield 1H and 17O chemical shifts and peak intensity ratios, which are then used to help assign the experimental MAS NMR spectra. Three distinct 1H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer. The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. 1H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C. Three distinct types of oxygen atoms are evident from the DFT GIPAW calculations bare oxygens (O), oxygens directly bonded to a proton (H-donor O), and oxygen ions that are hydrogen bonded to a proton (H-acceptor O). The 17O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by 1H–17O double resonance experiments. PMID:26321789

LEED-AES-Thin Layer Electrochemical Studies of Hydrogen Adsorption on Platinum Single Crystals.

DTIC Science & Technology

1982-08-01

of the voltametry sweep and has been observed in HF but not H2SO4 as the electrolyte (1). This anomalous behavior is not easily explained by any...Fig. 3. Cyclic linear sweep voltametry curve for Pt(3ll) in 0.1 N WF. Sveep rate: 50 uV/s. Solid line: secoad cycle 0.05 to 0.5 V; dotted line: fourth...Without such cycling, the hydrogen region of the voltametry curves usually does not yield well defined peaks in either polycrystalline or single crystal

Atomic Layer Deposition for the Conformal Coating of Nanoporous Materials

DOE PAGES

Elam, Jeffrey W.; Xiong, Guang; Han, Catherine Y.; ...

2006-01-01

Amore » tomic layer deposition ( LD ) is ideal for applying precise and conformal coatings over nanoporous materials. We have recently used LD to coat two nanoporous solids: anodic aluminum oxide ( O ) and silica aerogels. O possesses hexagonally ordered pores with diameters d ∼ 40 nm and pore length L ∼ 70 microns. The O membranes were coated by LD to fabricate catalytic membranes that demonstrate remarkable selectivity in the oxidative dehydrogenation of cyclohexane. dditional O membranes coated with LD Pd films show promise as hydrogen sensors. Silica aerogels have the lowest density and highest surface area of any solid material. Consequently, these materials serve as an excellent substrate to fabricate novel catalytic materials and gas sensors by LD .« less

Graphene oxide/metal nanocrystal multilaminates as the atomic limit for safe and selective hydrogen storage.

PubMed

Cho, Eun Seon; Ruminski, Anne M; Aloni, Shaul; Liu, Yi-Sheng; Guo, Jinghua; Urban, Jeffrey J

2016-02-23

Interest in hydrogen fuel is growing for automotive applications; however, safe, dense, solid-state hydrogen storage remains a formidable scientific challenge. Metal hydrides offer ample storage capacity and do not require cryogens or exceedingly high pressures for operation. However, hydrides have largely been abandoned because of oxidative instability and sluggish kinetics. We report a new, environmentally stable hydrogen storage material constructed of Mg nanocrystals encapsulated by atomically thin and gas-selective reduced graphene oxide (rGO) sheets. This material, protected from oxygen and moisture by the rGO layers, exhibits exceptionally dense hydrogen storage (6.5 wt% and 0.105 kg H2 per litre in the total composite). As rGO is atomically thin, this approach minimizes inactive mass in the composite, while also providing a kinetic enhancement to hydrogen sorption performance. These multilaminates of rGO-Mg are able to deliver exceptionally dense hydrogen storage and provide a material platform for harnessing the attributes of sensitive nanomaterials in demanding environments.

Non-invasive NMR stratigraphy of a multi-layered artefact: an ancient detached mural painting.

PubMed

Di Tullio, Valeria; Capitani, Donatella; Presciutti, Federica; Gentile, Gennaro; Brunetti, Brunetto Giovanni; Proietti, Noemi

2013-10-01

NMR stratigraphy was used to investigate in situ, non-destructively and non-invasively, the stratigraphy of hydrogen-rich layers of an ancient Nubian detached mural painting. Because of the detachment procedure, a complex multi-layered artefact was obtained, where, besides layers of the original mural painting, also the materials used during the procedure all became constitutive parts of the artefact. NMR measurements in situ enabled monitoring of the state of conservation of the artefact and planning of minimum representative sampling to validate results obtained in situ by solid-state NMR analysis of the samples. This analysis enabled chemical characterization of all organic materials. Use of reference compounds and prepared specimens assisted data interpretation.

Analytical Modeling of Variable Density Multilayer Insulation for Cryogenic Storage

NASA Technical Reports Server (NTRS)

Hedayat, A.; Hastings, L. J.; Brown, T.; Cruit, Wendy (Technical Monitor)

2001-01-01

A unique foam/Multilayer Insulation (MLI) combination concept for orbital cryogenic storage was experimentally evaluated at NASA Marshall Space Flight Center (MSFC) using the Multipurpose Hydrogen Test Bed (MHTB). The MLI was designed for an on-orbit storage period of 45 days and included several unique features such as: a variable layer density and larger but fewer perforations for venting during ascent to orbit. Test results with liquid hydrogen indicated that the MLI weight or heat leak is reduced by about half in comparison with standard MLI. The focus of this paper is on analytical modeling of the Variable Density MLI (VD-MLI) on-orbit performance (i.e. vacuum/low pressure environment). The foam/VD-MLI combination model is considered to have five segments. The first segment represents the optional foam layer. The second, third, and fourth segments represent three MLI segments with different layer densities. The last segment is considered to be a shroud that surrounds the last MLI layer. Two approaches are considered. In the first approach, the variable density MLI is modeled layer by layer while in the second approach, a semi-empirical model is applied. Both models account for thermal radiation between shields, gas conduction, and solid conduction through the layer separator materials.

Weak hydrogen bonding interactions influence slip system activity and compaction behavior of pharmaceutical powders.

PubMed

Khomane, Kailas S; Bansal, Arvind K

2013-12-01

Markedly different mechanical behavior of powders of polymorphs, cocrystals, hydrate/anhydrate pairs, or structurally similar molecules has been attributed to the presence of active slip planes system in their crystal structures. Presence of slip planes in the crystal lattice allows easier slip under the applied compaction pressure. This allows greater plastic deformation of the powder and results into increased interparticulate bonding area and greater tensile strength of the compacts. Thus, based on this crystallographic feature, tableting performance of the active pharmaceutical ingredients can be predicted. Recently, we encountered a case where larger numbers of CH···O type interactions across the proposed slip planes hinder the slip and thus resist plastic deformation of the powder under the applied compaction pressure. Hence, attention must be given to these types of interactions while identifying slip planes by visualization method. Generally, slip planes are visualized as flat layers often strengthened by a two-dimensional hydrogen-bonding network within the layers or planes. No hydrogen bonding should exist between these layers to consider them as slip planes. Moreover, one should also check the presence of CH···O type interactions across these planes. Mercury software provides an option for visualization of these weak hydrogen bonding interactions. Hence, caution must be exercised while selecting appropriate solid form based on this crystallographic feature. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

"Solid State" Chemistry in Titan Ice Particles

NASA Image and Video Library

2016-09-20

Scientists from NASA's Cassini mission suggested in a 2016 paper that the appearance of a cloud of dicyanoacetylene (C4N2) ice in Titan's stratosphere may be explained by "solid-state" chemistry taking place inside ice particles. The particles have an inner layer of cyanoacetylene (HC3N) ice coated with an outer layer of hydrogen cyanide (HCN) ice. Left: When a photon of light penetrates the outer shell, it can interact with the HC3N, producing C3N and H. Center: The C3N then reacts with HCN to yield C4N2 and H (shown at right). Another reaction that also yields C4N2 ice and H also is possible, but the researchers think it is less likely. http://photojournal.jpl.nasa.gov/catalog/PIA20715

An infrared spectroscopic study of the structural phase transition in the perovskite-type layer compound [ n-C 16H 33NH 3] 2CoCl 4

NASA Astrophysics Data System (ADS)

Ning, Guo; Guangfu, Zeng; Shiquan, Xi

1992-12-01

The solid-solid phase transitions in the perovskite-type layer compound [ n-C 16H 33NH 3] 2CoCl 4 have been studied by infrared spectroscopy. A new phase transition at 340 K was found by comparison with differential scanning calorimetry results. A temperature dependence study of the infrared spectra provides evidence of the occurrence of structural phase transitions related to the dynamics of the alkylammonium ions and hydrogen bonds. The main transition at 374 K corresponds to the conformational order-disorder change in the chain, which probably couples with reorientational motions of the NH 3 polar heads. GTG or GTG' defects appear in the high temperature disordered phase.

Sandwich-type electrode

DOEpatents

Lu, Wen-Tong P.; Garcia, Earl R.

1983-01-01

Disclosed is an improvement on a method of making an electrode wherein a suspension in a liquid is prepared of a powdered catalyst containing a noble metal, carbon powder and a binder, and the suspension is poured over a carbon substrate dried, compressed and sintered to form a solid catalyst layer bonded to the carbon substrate. The improvement is placing a carbon paper on the catalyst layer prior to compressing. The improved electrode can be used as either a cathode or an anode in a sulfur dioxide depolarized electrolyzer in a process for producing hydrogen from water.

Modeling Deuterium Release from Plasma Implanted Surfaces

NASA Astrophysics Data System (ADS)

Grossman, A. A.; Doerner, R.; Hirooka, Y.; Luckhardt, S. C.; Sze, F. C.

1997-11-01

When energetic ions or atoms of hydrogen isotopes interact with a solid surface, they may either be reflected or they may be implanted, a slowing down process within the subsurface layer of the energetic particles to thermal velocities. Subsequent interactions of the thermalized particles are those of diffusion and trapping within the material and the possibility of re-emission from the solid via desorption. The diffusion equation and its boundary conditions govern the transport of this thermalized hydrogen within the material. Diffusivities obey an Arrhenius law over as much as fourteen orders of magnitude for the temperature range of interest for a fusion reactor first wall and divertor plate. Using TMAP4, a variety of diffusion models are set up for comparison with experiments on PISCES which involve implantation and desorption of deuterium from beryllium, tungsten, carbon and boron carbide. The parameters and characteristics of the models which give the closest fit to the experimental data are reported. At the high fluences of these experiments, it is necessary to take into account saturation effects during implantation using a separate implantation layer with thickness given by TRIM and a higher trapping to lattice ratio than in the bulk in order to model the experimental data.

Metal Hydride Nanoparticles with Ultrahigh Structural Stability and Hydrogen Storage Activity Derived from Microencapsulated Nanoconfinement.

PubMed

Zhang, Jiguang; Zhu, Yunfeng; Lin, Huaijun; Liu, Yana; Zhang, Yao; Li, Shenyang; Ma, Zhongliang; Li, Liquan

2017-06-01

Metal hydrides (MHs) have recently been designed for hydrogen sensors, switchable mirrors, rechargeable batteries, and other energy-storage and conversion-related applications. The demands of MHs, particular fast hydrogen absorption/desorption kinetics, have brought their sizes to nanoscale. However, the nanostructured MHs generally suffer from surface passivation and low aggregation-resisting structural stability upon absorption/desorption. This study reports a novel strategy named microencapsulated nanoconfinement to realize local synthesis of nano-MHs, which possess ultrahigh structural stability and superior desorption kinetics. Monodispersed Mg 2 NiH 4 single crystal nanoparticles (NPs) are in situ encapsulated on the surface of graphene sheets (GS) through facile gas-solid reactions. This well-defined MgO coating layer with a thickness of ≈3 nm efficiently separates the NPs from each other to prevent aggregation during hydrogen absorption/desorption cycles, leading to excellent thermal and mechanical stability. More interestingly, the MgO layer shows superior gas-selective permeability to prevent further oxidation of Mg 2 NiH 4 meanwhile accessible for hydrogen absorption/desorption. As a result, an extremely low activation energy (31.2 kJ mol -1 ) for the dehydrogenation reaction is achieved. This study provides alternative insights into designing nanosized MHs with both excellent hydrogen storage activity and thermal/mechanical stability exempting surface modification by agents. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unraveling Complexity in the Solid Form Screening of a Pharmaceutical Salt: Why so Many Forms? Why so Few?

PubMed Central

2017-01-01

The solid form landscape of 5-HT2a antagonist 3-(4-(benzo[d]isoxazole-3-yl)piperazin-1-yl)-2,2-dimethylpropanoic acid hydrochloride (B5HCl) proved difficult to establish. Many crystalline materials were produced by solid form screening, but few forms readily grew high quality crystals to afford a clear picture or understanding of the solid form landscape. Careful control of crystallization conditions, a range of experimental methods, computational modeling of solvate structures, and crystal structure prediction were required to see potential arrangements of the salt in its crystal forms. Structural diversity in the solid form landscape of B5HCl was apparent in the layer structures for the anhydrate polymorphs (Forms I and II), dihydrate and a family of solvates with alcohols. The alcohol solvates, which provided a distinct packing from the neat forms and the dihydrate, form layers with conserved hydrogen bonding between B5HCl and the solvent, as well as stacking of the aromatic rings. The ability of the alcohol hydrocarbon moieties to efficiently pack between the layers accounted for the difficulty in growing some solvate crystals and the inability of other solvates to crystallize altogether. Through a combination of experiment and computation, the crystallization problems, form stability, and desolvation pathways of B5HCl have been rationalized at a molecular level. PMID:29018305

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Eun Seon; Ruminski, Anne M.; Aloni, Shaul

Interest in hydrogen fuel is growing for automotive applications; however, safe, dense, solid-state hydrogen storage remains a formidable scientific challenge. Metal hydrides offer ample storage capacity and do not require cryogens or exceedingly high pressures for operation. However, hydrides have largely been abandoned because of oxidative instability and sluggish kinetics. We report a new, environmentally stable hydrogen storage material constructed of Mg nanocrystals encapsulated by atomically thin and gas-selective reduced graphene oxide (rGO) sheets. This material, protected from oxygen and moisture by the rGO layers, exhibits exceptionally dense hydrogen storage (6.5 wt% and 0.105 kg H 2 per litre inmore » the total composite). As rGO is atomically thin, this approach minimizes inactive mass in the composite, while also providing a kinetic enhancement to hydrogen sorption performance. In conclusion, these multilaminates of rGO-Mg are able to deliver exceptionally dense hydrogen storage and provide a material platform for harnessing the attributes of sensitive nanomaterials in demanding environments.« less

Dense, layered membranes for hydrogen separation

DOEpatents

Roark, Shane E.; MacKay, Richard; Mundschau, Michael V.

2006-02-21

This invention provides hydrogen-permeable membranes for separation of hydrogen from hydrogen-containing gases. The membranes are multi-layer having a central hydrogen-permeable layer with one or more catalyst layers, barrier layers, and/or protective layers. The invention also relates to membrane reactors employing the hydrogen-permeable membranes of the invention and to methods for separation of hydrogen from a hydrogen-containing gas using the membranes and reactors. The reactors of this invention can be combined with additional reactor systems for direct use of the separated hydrogen.

The structure and unconventional dihydrogen bonding of a pressure-stabilized hydrogen-rich (NH 3BH 3)(H 2) x(x = 1.5) compound

DOE PAGES

Lin, Yu; Welchman, Evan; Thonhauser, Timo; ...

2017-03-15

Combining X-ray diffraction, Raman spectroscopy, and ab initio simulations we characterize an extremely hydrogen-rich phase with the chemical formula (NH 3BH 3)(H 2) x (x = 1.5). This phase was formed by compressing ammonia borane (AB, NH 3BH 3) in an environment with an excess of molecular hydrogen (H 2). This compound can store a total of 26.8 wt% hydrogen, both as molecular hydrogen and chemically bonded hydrogen in AB, making it one of the most hydrogen-rich solids currently known. The new compound possesses a layered AB structure where additional H 2 molecules reside in channels created through the weavingmore » of AB layers. The unconventional dihydrogen bonding network of the new compound is significantly modified from its parent AB phase and contains H•••H contacts between adjacent AB molecules and between AB and H 2 molecules. H–H can be either a proton donor or a proton acceptor that forms new types of dihydrogen bonding with the host AB molecules, which are depicted as H–H•••H–B or H–H•••H–N, respectively. Furthermore, this study not only demonstrates the strategy and the promise of using pressure for new material synthesis, but also unleashes the power of combining experiments and ab initio calculations for elucidating novel structures and unusual bonding configurations in dense low-Z materials.« less

The structure and unconventional dihydrogen bonding of a pressure-stabilized hydrogen-rich (NH 3BH 3)(H 2) x(x = 1.5) compound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yu; Welchman, Evan; Thonhauser, Timo

Combining X-ray diffraction, Raman spectroscopy, and ab initio simulations we characterize an extremely hydrogen-rich phase with the chemical formula (NH 3BH 3)(H 2) x (x = 1.5). This phase was formed by compressing ammonia borane (AB, NH 3BH 3) in an environment with an excess of molecular hydrogen (H 2). This compound can store a total of 26.8 wt% hydrogen, both as molecular hydrogen and chemically bonded hydrogen in AB, making it one of the most hydrogen-rich solids currently known. The new compound possesses a layered AB structure where additional H 2 molecules reside in channels created through the weavingmore » of AB layers. The unconventional dihydrogen bonding network of the new compound is significantly modified from its parent AB phase and contains H•••H contacts between adjacent AB molecules and between AB and H 2 molecules. H–H can be either a proton donor or a proton acceptor that forms new types of dihydrogen bonding with the host AB molecules, which are depicted as H–H•••H–B or H–H•••H–N, respectively. Furthermore, this study not only demonstrates the strategy and the promise of using pressure for new material synthesis, but also unleashes the power of combining experiments and ab initio calculations for elucidating novel structures and unusual bonding configurations in dense low-Z materials.« less

Structural Properties, Order–Disorder Phenomena, and Phase Stability of Orotic Acid Crystal Forms

PubMed Central

2016-01-01

Orotic acid (OTA) is reported to exist in the anhydrous (AH), monohydrate (Hy1), and dimethyl sulfoxide monosolvate (SDMSO) forms. In this study we investigate the (de)hydration/desolvation behavior, aiming at an understanding of the elusive structural features of anhydrous OTA by a combination of experimental and computational techniques, namely, thermal analytical methods, gravimetric moisture (de)sorption studies, water activity measurements, X-ray powder diffraction, spectroscopy (vibrational, solid-state NMR), crystal energy landscape, and chemical shift calculations. The Hy1 is a highly stable hydrate, which dissociates above 135 °C and loses only a small part of the water when stored over desiccants (25 °C) for more than one year. In Hy1, orotic acid and water molecules are linked by strong hydrogen bonds in nearly perfectly planar arranged stacked layers. The layers are spaced by 3.1 Å and not linked via hydrogen bonds. Upon dehydration the X-ray powder diffraction and solid-state NMR peaks become broader, indicating some disorder in the anhydrous form. The Hy1 stacking reflection (122) is maintained, suggesting that the OTA molecules are still arranged in stacked layers in the dehydration product. Desolvation of SDMSO, a nonlayer structure, results in the same AH phase as observed upon dehydrating Hy1. Depending on the desolvation conditions, different levels of order–disorder of layers present in anhydrous OTA are observed, which is also suggested by the computed low energy crystal structures. These structures provide models for stacking faults as intergrowth of different layers is possible. The variability in anhydrate crystals is of practical concern as it affects the moisture dependent stability of AH with respect to hydration. PMID:26741914

Bacteria-directed construction of hollow TiO2 micro/nanostructures with enhanced photocatalytic hydrogen evolution activity.

PubMed

Zhou, Han; Fan, Tongxiang; Ding, Jian; Zhang, Di; Guo, Qixin

2012-03-12

A general method has been developed for the synthesis of various hollow TiO2 micro/nanostructures with bacteria as templates to further study the structural effect on photocatalytic hydrogen evolution properties. TiO2 hollow spheres and hollow tubes, served as prototypes, are obtained via a surface sol-gel process using cocci and bacillus as biotemplates, respectively. The formation mechanisms are based on absorption of metal-alkoxide molecules from solution onto functional cell wall surfaces and subsequent hydrolysis to give nanometer-thick oxide layers. The UV-Vis absorption spectrum shows that the porous TiO2 hollow spheres have enhanced light harvesting property compared with the corresponding solid counterpart. This could be attributed to their unique hollow porous micro/nanostructures with microsized hollow cavities and nanovoids which could bring about multiple scattering and rayleigh scattering of light, respectively. The hollow TiO2 structures exhibit superior photocatalytic hydrogen evolution activities under UV and visible light irradiation in the presence of sacrificial reagents. The hydrogen evolution rate of hollow structures is about 3.6 times higher than the solid counterpart and 1.5 times higher than P25-TiO2. This work demonstrates the structural effect on enhancing the photocatalytic hydrogen evolution performance which would pave a new pathway to tailor and improve catalytic properties over a broad range.

Graphene oxide/metal nanocrystal multilaminates as the atomic limit for safe and selective hydrogen storage

DOE PAGES

Cho, Eun Seon; Ruminski, Anne M.; Aloni, Shaul; ...

2016-02-23

Interest in hydrogen fuel is growing for automotive applications; however, safe, dense, solid-state hydrogen storage remains a formidable scientific challenge. Metal hydrides offer ample storage capacity and do not require cryogens or exceedingly high pressures for operation. However, hydrides have largely been abandoned because of oxidative instability and sluggish kinetics. We report a new, environmentally stable hydrogen storage material constructed of Mg nanocrystals encapsulated by atomically thin and gas-selective reduced graphene oxide (rGO) sheets. This material, protected from oxygen and moisture by the rGO layers, exhibits exceptionally dense hydrogen storage (6.5 wt% and 0.105 kg H 2 per litre inmore » the total composite). As rGO is atomically thin, this approach minimizes inactive mass in the composite, while also providing a kinetic enhancement to hydrogen sorption performance. In conclusion, these multilaminates of rGO-Mg are able to deliver exceptionally dense hydrogen storage and provide a material platform for harnessing the attributes of sensitive nanomaterials in demanding environments.« less

Insight into hydrogen bonding of uranyl hydroxide layers and capsules by use of 1H magic-angle spinning NMR spectroscopy [Insight into the hydrogen bonding for uranyl hydroxides using 1H MAS NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alam, Todd M.; Liao, Zuolei; Nyman, May

Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO 2(OH) 2] (α-UOH) and hydrated uranyl hydroxide [(UO 2) 4O(OH) 6·5H 2O (metaschoepite). For the metaschoepite material, proton resonances of the μ 2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H– 1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Furthermore, these NMR correlations allowed characterization ofmore » local hydrogen-bond environments in uranyl U 24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.« less

Insight into hydrogen bonding of uranyl hydroxide layers and capsules by use of 1H magic-angle spinning NMR spectroscopy [Insight into the hydrogen bonding for uranyl hydroxides using 1H MAS NMR spectroscopy

DOE PAGES

Alam, Todd M.; Liao, Zuolei; Nyman, May; ...

2016-04-27

Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO 2(OH) 2] (α-UOH) and hydrated uranyl hydroxide [(UO 2) 4O(OH) 6·5H 2O (metaschoepite). For the metaschoepite material, proton resonances of the μ 2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H– 1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Furthermore, these NMR correlations allowed characterization ofmore » local hydrogen-bond environments in uranyl U 24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.« less

Atomically layer-by-layer diffusion of oxygen/hydrogen in highly epitaxial PrBaCo2O5.5+δ thin films

NASA Astrophysics Data System (ADS)

Bao, Shanyong; Xu, Xing; Enriquez, Erik; Mace, Brennan E.; Chen, Garry; Kelliher, Sean P.; Chen, Chonglin; Zhang, Yamei; Whangbo, Myung-Hwan; Dong, Chuang; Zhang, Qinyu

2015-12-01

Single-crystalline epitaxial thin films of PrBaCo2O5.5+δ (PrBCO) were prepared, and their resistance R(t) under a switching flow of oxidizing and reducing gases were measured as a function of the gas flow time t in the temperature range of 200-800 °C. During the oxidation cycle under O2, the PrBCO films exhibit fast oscillations in their dR(t)/dt vs. t plots, which reflect the oxidation processes, Co2+/Co3+ → Co3+ and Co3+ → Co3+/Co4+, that the Co atoms of PrBCO undergo. Each oscillation consists of two peaks, with larger and smaller peaks representing the oxygen/hydrogen diffusion through the (BaO)(CoO2)(PrO)(CoO2) layers of PrBCO via the oxygen-vacancy-exchange mechanism. This finding paves a significant avenue for cathode materials operating in low-temperature solid-oxide-fuel-cell devices and for chemical sensors with wide range of operating temperature.

Zwitterionic 4-bromo-6-meth-oxy-2-{[tris-(hy-droxy-meth-yl)methyl]-iminiumyl-meth-yl}phenolate: crystal structure and Hirshfeld surface analysis.

PubMed

Lee, See Mun; Lo, Kong Mun; Tan, Sang Loon; Tiekink, Edward R T

2016-08-01

In the solid state, the title compound, C12H16BrNO5 [systematic name: 4-bromo-2-((1E)-{[1,3-dihy-droxy-2-(hy-droxy-meth-yl)propan-2-yl]iminium-yl}meth-yl)-6-meth-oxy-benzen-1-olate], C12H16BrNO5, is found in the keto-amine tautomeric form, with an intra-molecular iminium-N-H⋯O(phenolate) hydrogen bond and an E conformation about the C=N bond. Both gauche (two) and anti relationships are found for the methyl-hydroxy groups. In the crystal, a supra-molecular layer in the bc plane is formed via hy-droxy-O-H⋯O(hy-droxy) and charge-assisted hy-droxy-O-H⋯O(phenolate) hydrogen-bonding inter-actions; various C-H⋯O inter-actions provide additional cohesion to the layers, which stack along the a axis with no directional inter-actions between them. A Hirshfeld surface analysis confirms the lack of specific inter-actions in the inter-layer region.

Membrane for hydrogen recovery from streams containing hydrogen sulfide

DOEpatents

Agarwal, Pradeep K.

2007-01-16

A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

Paramagnetic Attraction of Impurity-Helium Solids

NASA Technical Reports Server (NTRS)

Bernard, E. P.; Boltnev, R. E.; Khmelenko, V. V.; Lee, D. M.

2003-01-01

Impurity-helium solids are formed when a mixture of impurity and helium gases enters a volume of superfluid helium. Typical choices of impurity gas are hydrogen deuteride, deuterium, nitrogen, neon and argon, or a mixture of these. These solids consist of individual impurity atoms and molecules as well as clusters of impurity atoms and molecules covered with layers of solidified helium. The clusters have an imperfect crystalline structure and diameters ranging up to 90 angstroms, depending somewhat on the choice of impurity. Immediately following formation the clusters aggregate into loosely connected porous solids that are submerged in and completely permeated by the liquid helium. Im-He solids are extremely effective at stabilizing high concentrations of free radicals, which can be introduced by applying a high power RF dis- charge to the impurity gas mixture just before it strikes the super fluid helium. Average concentrations of 10(exp 19) nitrogen atoms/cc and 5 x 10(exp 18) deuterium atoms/cc can be achieved this way. It shows a typical sample formed from a mixture of atomic and molecular hydrogen and deuterium. It shows typical sample formed from atomic and molecular nitrogen. Much of the stability of Im-He solids is attributed to their very large surface area to volume ratio and their permeation by super fluid helium. Heat resulting from a chance meeting and recombination of free radicals is quickly dissipated by the super fluid helium instead of thermally promoting the diffusion of other nearby free radicals.

Integrated lunar materials manufacturing process

NASA Technical Reports Server (NTRS)

Gibson, Michael A. (Inventor); Knudsen, Christian W. (Inventor)

1990-01-01

A manufacturing plant and process for production of oxygen on the moon uses lunar minerals as feed and a minimum of earth-imported, process materials. Lunar feed stocks are hydrogen-reducible minerals, ilmenite and lunar agglutinates occurring in numerous, explored locations mixed with other minerals in the pulverized surface layer of lunar soil known as regolith. Ilmenite (FeTiO.sub.3) and agglutinates contain ferrous (Fe.sup.+2) iron reducible by hydrogen to yield H.sub.2 O and metallic Fe at about 700.degree.-1,200.degree. C. The H.sub.2 O is electrolyzed in gas phase to yield H.sub.2 for recycle and O.sub.2 for storage and use. Hydrogen losses to lunar vacuum are minimized, with no net hydrogen (or any other earth-derived reagent) consumption except for small leaks. Feed minerals are surface-mined by front shovels and transported in trucks to the processing area. The machines are manned or robotic. Ilmenite and agglutinates occur mixed with silicate minerals which are not hydrogen-reducible at 700.degree.-1,200.degree. C. and consequently are separated and concentrated before feeding to the oxygen generation process. Solids rejected from the separation step and reduced solids from the oxygen process are returned to the mine area. The plant is powered by nuclear or solar power generators. Vapor-phase water electrolysis, a staged, countercurrent, fluidized bed reduction reactor and a radio-frequency-driven ceramic gas heater are used to improve thermal efficiency.

Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

DOEpatents

Lessing, Paul A [Idaho Falls, ID

2008-07-22

An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

DOEpatents

Lessing, Paul A.

2004-09-07

An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

Solid Hydrogen Experiments for Atomic Propellants: Image Analyses

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan

2002-01-01

This paper presents the results of detailed analyses of the images from experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Solid particles of hydrogen were frozen in liquid helium, and observed with a video camera. The solid hydrogen particle sizes, their agglomerates, and the total mass of hydrogen particles were estimated. Particle sizes of 1.9 to 8 mm (0.075 to 0.315 in.) were measured. The particle agglomerate sizes and areas were measured, and the total mass of solid hydrogen was computed. A total mass of from 0.22 to 7.9 grams of hydrogen was frozen. Compaction and expansion of the agglomerate implied that the particles remain independent particles, and can be separated and controlled. These experiment image analyses are one of the first steps toward visually characterizing these particles, and allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

Method of production of pure hydrogen near room temperature from aluminum-based hydride materials

DOEpatents

Pecharsky, Vitalij K.; Balema, Viktor P.

2004-08-10

The present invention provides a cost-effective method of producing pure hydrogen gas from hydride-based solid materials. The hydride-based solid material is mechanically processed in the presence of a catalyst to obtain pure gaseous hydrogen. Unlike previous methods, hydrogen may be obtained from the solid material without heating, and without the addition of a solvent during processing. The described method of hydrogen production is useful for energy conversion and production technologies that consume pure gaseous hydrogen as a fuel.

Solid-state chelation of metal ions by ethylenediaminetetraacetate intercalated in a layered double hydroxide.

PubMed

Tarasov, Konstantin A; O'Hare, Dermot; Isupov, Vitaly P

2003-03-24

The solid-state chelation of transition metal ions (Co(2+), Ni(2+), and Cu(2+)) from aqueous solutions into the lithium aluminum layered double hydroxide ([LiAl(2)(OH)(6)]Cl x 0.5H(2)O or LDH) which has been pre-intercalated with EDTA (ethylenediaminetetraacetate) ligand has been investigated. The intercalated metal cations form [M(edta)](2)(-) complexes between the LDH layers as indicated by elemental analysis, powder X-ray diffraction, and IR and UV-vis spectroscopies. If metal chloride or nitrate salts are used in the reaction with the LDH then co-intercalation of either the Cl(-) or NO(3)(-) anions is observed. In the case of metal acetate salts the cations intercalate without the accompanying anion. This can be explained by the different intercalation selectivity of the anions in relation to the LDH. In the latter case the introduction of the positive charge into LDH structure was compensated for by the release from the solid of the equivalent quantity of lithium and hydrogen cations. Time-resolved in-situ X-ray diffraction measurements have revealed that the chelation/intercalation reactions proceed very quickly. The rate of the reaction found for nickel acetate depends on concentration as approximately k[Ni(Ac)(2)](3).

Electrochemical investigation of mixed metal oxide nanocomposite electrode for low temperature solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Abbas, Ghazanfar; Raza, Rizwan; Ashfaq Ahmad, M.; Ajmal Khan, M.; Jafar Hussain, M.; Ahmad, Mukhtar; Aziz, Hammad; Ahmad, Imran; Batool, Rida; Altaf, Faizah; Zhu, Bin

2017-10-01

Zinc-based nanostructured nickel (Ni) free metal oxide electrode material Zn0.60/Cu0.20Mn0.20 oxide (CMZO) was synthesized by solid state reaction and investigated for low temperature solid oxide fuel cell (LTSOFC) applications. The crystal structure and surface morphology of the synthesized electrode material were examined by XRD and SEM techniques respectively. The particle size of ZnO phase estimated by Scherer’s equation was 31.50 nm. The maximum electrical conductivity was found to be 12.567 S/cm and 5.846 S/cm in hydrogen and air atmosphere, respectively at 600∘C. The activation energy of the CMZO material was also calculated from the DC conductivity data using Arrhenius plots and it was found to be 0.060 and 0.075 eV in hydrogen and air atmosphere, respectively. The CMZO electrode-based fuel cell was tested using carbonated samarium doped ceria composite (NSDC) electrolyte. The three layers 13 mm in diameter and 1 mm thickness of the symmetric fuel cell were fabricated by dry pressing. The maximum power density of 728.86 mW/cm2 was measured at 550∘C.

Performance evaluation of a liquid tin anode solid oxide fuel cell operating under hydrogen, argon and coal

NASA Astrophysics Data System (ADS)

Khurana, Sanchit; LaBarbera, Mark; Fedkin, Mark V.; Lvov, Serguei N.; Abernathy, Harry; Gerdes, Kirk

2015-01-01

A liquid tin anode solid oxide fuel cell is constructed and investigated under different operating conditions. Electrochemical Impedance Spectroscopy (EIS) is used to reflect the effect of fuel feed as the EIS spectra changes significantly on switching the fuel from argon to hydrogen. A cathode symmetric cell is used to separate the impedance from the two electrodes, and the results indicate that a major contribution to the charge-transfer and mass-transfer impedance arises from the anode. The OCP of 0.841 V for the cell operating under argon as a metal-air battery indicates the formation of a SnO2 layer at the electrolyte/anode interface. The increase in the OCP to 1.1 V for the hydrogen fueled cell shows that H2 reduces the SnO2 film effectively. The effective diffusion coefficients are calculated using the Warburg element in the equivalent circuit model for the experimental EIS data, and the values of 1.9 10-3 cm2 s-1 at 700 °C, 2.3 10-3 cm2 s-1 at 800 °C and 3.5 10-3 cm2 s-1 at 900 °C indicate the system was influenced by diffusion of hydrogen in the system. Further, the performance degradation over time is attributed to the irreversible conversion of Sn to SnO2 resulting from galvanic polarization.

Boron-Based Hydrogen Storage: Ternary Borides and Beyond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vajo, John J.

DOE continues to seek reversible solid-state hydrogen materials with hydrogen densities of ≥11 wt% and ≥80 g/L that can deliver hydrogen and be recharged at moderate temperatures (≤100 °C) and pressures (≤100 bar) enabling incorporation into hydrogen storage systems suitable for transportation applications. Boron-based hydrogen storage materials have the potential to meet the density requirements given boron’s low atomic weight, high chemical valance, and versatile chemistry. However, the rates of hydrogen exchange in boron-based compounds are thus far much too slow for practical applications. Although contributing to the high hydrogen densities, the high valance of boron also leads to slowmore » rates of hydrogen exchange due to extensive boron-boron atom rearrangements during hydrogen cycling. This rearrangement often leads to multiple solid phases occurring over hydrogen release and recharge cycles. These phases must nucleate and react with each other across solid-solid phase boundaries leading to energy barriers that slow the rates of hydrogen exchange. This project sought to overcome the slow rates of hydrogen exchange in boron-based hydrogen storage materials by minimizing the number of solid phases and the boron atom rearrangement over a hydrogen release and recharge cycle. Two novel approaches were explored: 1) developing matched pairs of ternary borides and mixed-metal borohydrides that could exchange hydrogen with only one hydrogenated phase (the mixed-metal borohydride) and only one dehydrogenated phase (the ternary boride); and 2) developing boranes that could release hydrogen by being lithiated using lithium hydride with no boron-boron atom rearrangement.« less

Combined inelastic neutron scattering and solid state DFT study of dynamics of hydrogen atoms in trioctahedral 1M phlogopite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smrčok, Ľubomír; Kolesnikov, Alexander I; Rieder, Milan

2012-01-01

Inelastic neutron scattering (INS) was used to study vibrational dynamics of the hydrogen atoms in natural trioctahedral phlogopite, K0.93Na0.03(Mg2.47Fe0.22Al0.16Fe0.04Tl0.06)[Si2.84Al1.16]O10OH1.71F0.28Cl0.01, within the 50-1000 cm-1 energy range. The INS spectra collected using direct geometry spectrometer SEQUOIA at ORNL were interpreted by means of the solid-state DFT calculations covering both normal mode analysis and molecular dynamics. To optimize the structure and to calculate the vibrational modes under harmonic approximation both a hybrid PBE0 and the AM05 functional were used, while the molecular dynamics calculations (60ps/1fs) were performed only with the computationally less-demanding AM05 functional. The main contributions to the dominant band within ~750-550more » cm-1 are symmetric and antisymmetric Mg-O-H bending modes, overlapping with the skeletal stretching and bending modes causing weaker secondary movements of H atoms of inner hydroxyl groups. Signatures of the Mg-O-H bending modes appear down to ~400 cm-1, where a region of octahedra deformation modes starts. These deformations cause just shallow movements of the hydrogen atoms and are mirrored by the modes with close vibrational energies. The region from ~330 cm-1 down to the low energy end of the spectrum portrays induced vibrations of the H atoms caused by deformation of individual polyhedra, translational vibrations of the parts of the 2:1 layer relative one to another, and librational and translational vibrations of the layer. The main difference between the INS spectrum of dioctahedral Al-muscovite and trioctahedral Mg-phlogopite is that the Mg-O-H modes are all assigned to in-plane vibrations of the respective hydrogen atoms.« less

Combined inelastic neutron scattering and solid-state DFT study of dynamics of hydrogen atoms in trioctahedral 1 M phlogopite

NASA Astrophysics Data System (ADS)

Smrčok, L'ubomír; Kolesnikov, Alexander I.; Rieder, Milan

2012-10-01

Inelastic neutron scattering (INS) was used to study the vibrational dynamics of the hydrogen atoms in natural trioctahedral phlogopite, K0.93Na0.03(Mg2.47Fe0.22Al0.16Fe0.04Tl0.06)[Si2.84Al1.16]O10OH1.71F0.28Cl0.01, within the 50-1,000 cm-1 energy range. The INS spectra collected using direct geometry spectrometer SEQUOIA (ORNL) were interpreted by means of the solid-state DFT calculations covering both normal mode analysis and molecular dynamics. To optimize the structure and to calculate the vibrational modes under harmonic approximation, both a hybrid PBE0 and the AM05 functional were used, while the molecular dynamics calculations (60 ps/1 fs) were performed only with the computationally less-demanding AM05 functional. The main contributions to the dominant band within ~750-550 cm-1 are symmetric and antisymmetric Mg-O-H bending modes, overlapping with the skeletal stretching and bending modes causing weaker secondary movements of H atoms of inner hydroxyl groups. Signatures of the Mg-O-H bending modes appear down to ~400 cm-1, where a region of octahedra deformation modes starts. These deformations cause just shallow movements of the hydrogen atoms and are mirrored by the modes with close vibrational energies. The region from ~330 cm-1 down to the low-energy end of the spectrum portrays induced vibrations of the H atoms caused by deformation of individual polyhedra, translational vibrations of the parts of the 2:1 layer relative one to another, and librational and translational vibrations of the layer. The main difference between the INS spectrum of dioctahedral Al-muscovite and trioctahedral Mg-phlogopite is that the Mg-O-H modes are all assigned to in-plane vibrations of the respective hydrogen atoms.

Investigation of a para-ortho hydrogen reactor for application to spacecraft sensor cooling

NASA Technical Reports Server (NTRS)

Nast, T. C.

1983-01-01

The utilization of solid hydrogen in space for sensor and instrument cooling is a very efficient technique for long term cooling or for cooling at high heat rates. The solid hydrogen can provide temperatures as low as 7 to 8 K to instruments. Vapor cooling is utilized to reduce parasitic heat inputs to the 7 to 8 K stage and is effective in providing intermediate cooling for instrument components operating at higher temperatures. The use of solid hydrogen in place of helium may lead to weight reductions as large as a factor of ten and an attendent reduction in system volume. The results of an investigation of a catalytic reactor for use with a solid hydrogen cooling system is presented. Trade studies were performed on several configurations of reactor to meet the requirements of high reactor efficiency with low pressure drop. Results for the selected reactor design are presented for both liquid hydrogen systems operating at near atmospheric pressure and the solid hydrogen cooler operating as low as 1 torr.

Functionalized graphene-Pt composites for fuel cells and photoelectrochemical cells

DOEpatents

Diankov, Georgi; An, Jihwan; Park, Joonsuk; Goldhaber, David J. K.; Prinz, Friedrich B.

2017-08-29

A method of growing crystals on two-dimensional layered material is provided that includes reversibly hydrogenating a two-dimensional layered material, using a controlled radio-frequency hydrogen plasma, depositing Pt atoms on the reversibly hydrogenated two-dimensional layered material, using Atomic Layer Deposition (ALD), where the reversibly hydrogenated two-dimensional layered material promotes loss of methyl groups in an ALD Pt precursor, and forming Pt-O on the reversibly hydrogenated two-dimensional layered material, using combustion by O.sub.2, where the Pt-O is used for subsequent Pt half-cycles of the ALD process, where growth of Pt crystals occurs.

Nanointerface-driven reversible hydrogen storage in the nanoconfined Li-N-H system

DOE PAGES

Wood, Brandon C.; Stavila, Vitalie; Poonyayant, Natchapol; ...

2017-01-20

Internal interfaces in the Li 3N/[LiNH 2 + 2LiH] solid-state hydrogen storage system alter the hydrogenation and dehydrogenation reaction pathways upon nanosizing, suppressing undesirable intermediate phases to dramatically improve kinetics and reversibility. Finally, the key role of solid interfaces in determining thermodynamics and kinetics suggests a new paradigm for optimizing complex hydrides for solid-state hydrogen storage by engineering internal microstructure.

System for operating solid oxide fuel cell generator on diesel fuel

NASA Technical Reports Server (NTRS)

Singh, Prabhu (Inventor); George, Raymond A. (Inventor)

1997-01-01

A system is provided for operating a solid oxide fuel cell generator on diesel fuel. The system includes a hydrodesulfurizer which reduces the sulfur content of commercial and military grade diesel fuel to an acceptable level. Hydrogen which has been previously separated from the process stream is mixed with diesel fuel at low pressure. The diesel/hydrogen mixture is then pressurized and introduced into the hydrodesulfurizer. The hydrodesulfurizer comprises a metal oxide such as ZnO which reacts with hydrogen sulfide in the presence of a metal catalyst to form a metal sulfide and water. After desulfurization, the diesel fuel is reformed and delivered to a hydrogen separator which removes most of the hydrogen from the reformed fuel prior to introduction into a solid oxide fuel cell generator. The separated hydrogen is then selectively delivered to the diesel/hydrogen mixer or to a hydrogen storage unit. The hydrogen storage unit preferably comprises a metal hydride which stores hydrogen in solid form at low pressure. Hydrogen may be discharged from the metal hydride to the diesel/hydrogen mixture at low pressure upon demand, particularly during start-up and shut-down of the system.

Molecular dynamics studies of interfacial water at the alumina surface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Argyris, Dr. Dimitrios; Ho, Thomas; Cole, David

2011-01-01

Interfacial water properties at the alumina surface were investigated via all-atom equilibrium molecular dynamics simulations at ambient temperature. Al-terminated and OH-terminated alumina surfaces were considered to assess the structural and dynamic behavior of the first few hydration layers in contact with the substrates. Density profiles suggest water layering up to {approx}10 {angstrom} from the solid substrate. Planar density distribution data indicate that water molecules in the first interfacial layer are organized in well-defined patterns dictated by the atomic terminations of the alumina surface. Interfacial water exhibits preferential orientation and delayed dynamics compared to bulk water. Water exhibits bulk-like behavior atmore » distances greater than {approx}10 {angstrom} from the substrate. The formation of an extended hydrogen bond network within the first few hydration layers illustrates the significance of water?water interactions on the structural properties at the interface.« less

HIGH-PRESSURE PHYSICS. Direct observation of an abrupt insulator-to-metal transition in dense liquid deuterium.

PubMed

Knudson, M D; Desjarlais, M P; Becker, A; Lemke, R W; Cochrane, K R; Savage, M E; Bliss, D E; Mattsson, T R; Redmer, R

2015-06-26

Eighty years ago, it was proposed that solid hydrogen would become metallic at sufficiently high density. Despite numerous investigations, this transition has not yet been experimentally observed. More recently, there has been much interest in the analog of this predicted metallic transition in the dense liquid, due to its relevance to planetary science. Here, we show direct observation of an abrupt insulator-to-metal transition in dense liquid deuterium. Experimental determination of the location of this transition provides a much-needed benchmark for theory and may constrain the region of hydrogen-helium immiscibility and the boundary-layer pressure in standard models of the internal structure of gas-giant planets. Copyright © 2015, American Association for the Advancement of Science.

Thermodynamic characterization of hydrogen interaction with iridium polyhydride complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zidan, R.A.; Rocheleau, R.E.

1999-01-01

Hydrogen interaction with solid iridium complexes IrXH{sub 2}(PPr3{sup i}){sub 2} (X=Cl, I) was investigated. Gaseous hydrogen was found to react reversibly with solid chloro-iridium complex IrClH{sub 2}(PPr3{sup i}){sub 2} forming IrClH{sub 2}(PPr3{sup i}){sub 2}H{sub 2}. The relative partial molal enthalpy and entropy were obtained from equilibrium isotherms at different hydrogen concentrations. The decrease in entropy with increasing hydrogen concentration and the absence of plateaus in the equilibrium isotherms were consistent with a single phase solid solution with two chemical components. Hydrogen release from solid iodo-iridium complex IrIH{sub 2}(PPr3{sup i}){sub 2}H{sub 2} was not observed at temperatures up to 350 K,more » indicating stronger hydrogen bonding. {copyright} {ital 1999 Materials Research Society.}« less

Achieving High Efficiency and Eliminating Degradation in Solid Oxide Electrochemical Cells Using High Oxygen-Capacity Perovskite.

PubMed

Jun, Areum; Kim, Junyoung; Shin, Jeeyoung; Kim, Guntae

2016-09-26

Recently, there have been efforts to use clean and renewable energy because of finite fossil fuels and environmental problems. Owing to the site-specific and weather-dependent characteristics of the renewable energy supply, solid oxide electrolysis cells (SOECs) have received considerable attention to store energy as hydrogen. Conventional SOECs use Ni-YSZ (yttria-stabilized zirconia) and LSM (strontium-doped lanthanum manganites)-YSZ as electrodes. These electrodes, however, suffer from redox-instability and coarsening of the Ni electrode along with delamination of the LSM electrode during steam electrolysis. In this study, we successfully design and fabricate highly efficient SOECs using layered perovskites, PrBaMn2 O5+δ (PBM) and PrBa0.5 Sr0.5 Co1.5 Fe0.5 O5+δ (PBSCF50), as both electrodes for the first time. The SOEC with layered perovskites as both-side electrodes shows outstanding performance, reversible cycling, and remarkable stability over 600 hours. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method and means for producing solid evacuated microspheres of hydrogen

DOEpatents

Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

1976-01-01

A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

Solid evacuated microspheres of hydrogen

DOEpatents

Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

1982-01-01

A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

Shape-dependent hydrogen-storage properties in Pd nanocrystals: which does hydrogen prefer, octahedron (111) or cube (100)?

PubMed

Li, Guangqin; Kobayashi, Hirokazu; Dekura, Shun; Ikeda, Ryuichi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Matsumura, Syo; Kitagawa, Hiroshi

2014-07-23

Pd octahedrons and cubes enclosed by {111} and {100} facets, respectively, have been synthesized for investigation of the shape effect on hydrogen-absorption properties. Hydrogen-storage properties were investigated using in situ powder X-ray diffraction, in situ solid-state (2)H NMR and hydrogen pressure-composition isotherm measurements. With these measurements, it was found that the exposed facets do not affect hydrogen-storage capacity; however, they significantly affect the absorption speed, with octahedral nanocrystals showing the faster response. The heat of adsorption of hydrogen and the hydrogen diffusion pathway were suggested to be dominant factors for hydrogen-absorption speed. Furthermore, in situ solid-state (2)H NMR detected for the first time the state of (2)H in a solid-solution (Pd + H) phase of Pd nanocrystals at rt.

Hydrogen isotope and light element profiling in solid tritium targets used for neutron production

NASA Astrophysics Data System (ADS)

Earwaker, L. G.; England, J. B. A.; Goldie, D. J.

1987-04-01

Five targets consisting of titanium tritide layers on copper backings have been investigated using nuclear reaction analysis. As these targets are commonly used to produce monoenergetic neutrons via the T(p, n) 3 He and T(d, n) 4 He reactions, it is important to know of the presence of other elements which may produce neutrons at different energies. The thicknesses of the titanium tritide layers were measured by observing the T(p, n) 3 He threshold yield curve and also the energy spread of the neutrons using a 3He-filled gridded ion chamber. Elastic recoil analysis with a particle identifying system was used to measure the hydrogen, deuterium, tritium and 3He content, and elastic scattering was used to study the carbon and oxygen. Surprisingly high concentrations of both hydrogen and oxygen were found on all targets, including the three which had never been used. Also surprising was the 3He content which was approximately the same for targets of all ages and conditions of use. As expected, the carbon content increased strongly with use, originating no doubt, from vacuum pump oil. Up to 3% deuterium atoms were observed in unused targets with much higher contents being recorded in used targets.

Study of a solid hydrogen cooler for spacecraft instruments and sensors

NASA Astrophysics Data System (ADS)

Sherman, A.

1980-08-01

The results of tests and studies to investigate the utilization of solid hydrogen for cooling of spacecraft instruments and sensors are presented. The results are presented in two sections; the first describing the tests in which an existing single stage solid cooler was filled and tested with solid hydrogen and the second which describes the analysis and design of a catalytic converter which will be tested in the vent line of the cooler.

Study of a solid hydrogen cooler for spacecraft instruments and sensors

NASA Technical Reports Server (NTRS)

Sherman, A.

1980-01-01

The results of tests and studies to investigate the utilization of solid hydrogen for cooling of spacecraft instruments and sensors are presented. The results are presented in two sections; the first describing the tests in which an existing single stage solid cooler was filled and tested with solid hydrogen and the second which describes the analysis and design of a catalytic converter which will be tested in the vent line of the cooler.

One step growth of GaN/SiO2 core/shell nanowire in vapor-liquid-solid route by chemical vapor deposition technique

NASA Astrophysics Data System (ADS)

Barick, B. K.; Yadav, Shivesh; Dhar, S.

2017-11-01

GaN/SiO2 core/shell nanowires are grown by cobalt phthalocyanine catalyst assisted vapor-liquid-solid route, in which Si wafer coated with a mixture of gallium and indium is used as the source for Ga and Si and ammonia is used as the precursor for nitrogen and hydrogen. Gallium in the presence of indium and hydrogen, which results from the dissociation of ammonia, forms Si-Ga-In alloy at the growth temperature ∼910 °C. This alloy acts as the source of Si, Ga and In. A detailed study using a variety of characterization tools reveals that these wires, which are several tens of micron long, has a diameter distribution of the core ranging from 20 to 50 nm, while the thickness of the amorphous SiO2 shell layer is about 10 nm. These wires grow along [ 1 0 1 bar 0 ] direction. It has also been observed that the average diameter of these wires decreases, while their density increases as the gallium proportion in the Ga-In mixture is increased.

Analysis and Thermodynamic Prediction of Hydrogen Solution in Solid and Liquid Multicomponent Aluminum Alloys

NASA Astrophysics Data System (ADS)

Anyalebechi, P. N.

Reported experimentally determined values of hydrogen solubility in liquid and solid Al-H and Al-H-X (where X = Cu, Si, Zn, Mg, Li, Fe or Ti) systems have been critically reviewed and analyzed in terms of Wagner's interaction parameter. An attempt has been made to use Wagner's interaction parameter and statistic linear regression models derived from reported hydrogen solubility limits for binary aluminum alloys to predict the hydrogen solubility limits in liquid and solid (commercial) multicomponent aluminum alloys. Reasons for the observed poor agreement between the predicted and experimentally determined hydrogen solubility limits are discussed.

Composite hydrogen separation element and module

DOEpatents

Edlund, D.J.

1996-03-12

There are disclosed improvements in multicomponent composite metal membranes useful for the separation of hydrogen, the improvements comprising the provision of a flexible porous intermediate layer between a support layer and a nonporous hydrogen-permeable coating metal layer, and the provision of a textured coating metal layer. 15 figs.

Visible light photoreactivity from Carbon nitride bandgap states in Nb and Ti oxides

NASA Astrophysics Data System (ADS)

Lee, Hosik; Ohno, Takahisa; Icnsee Team

2011-03-01

Lamellar niobic and titanic solid acids (HNb3O8 , H2Ti4O9) are photocatalysts which can be used for environmental cleanup application and hydrogen production through water splitting. To increase their efficiency, bandgap adjustment which can induce visible light reactivity in addition to ultraviolet light has been one of hot issue in this kinds of photo-catalytic materials. Nitrogen-doping was one of the direction and its microscopic structures are disputed in this decade. In this work, we calculate the layered niobic and titanic solid acids structure and bandgap. Bandgap reduction by carbon nitride absorption are observed computationally. It is originated from localized nitrogen state which is consistent with previous experiments.

Conductive-probe atomic force microscopy characterization of silicon nanowire

PubMed Central

2011-01-01

The electrical conduction properties of lateral and vertical silicon nanowires (SiNWs) were investigated using a conductive-probe atomic force microscopy (AFM). Horizontal SiNWs, which were synthesized by the in-plane solid-liquid-solid technique, are randomly deployed into an undoped hydrogenated amorphous silicon layer. Local current mapping shows that the wires have internal microstructures. The local current-voltage measurements on these horizontal wires reveal a power law behavior indicating several transport regimes based on space-charge limited conduction which can be assisted by traps in the high-bias regime (> 1 V). Vertical phosphorus-doped SiNWs were grown by chemical vapor deposition using a gold catalyst-driving vapor-liquid-solid process on higly n-type silicon substrates. The effect of phosphorus doping on the local contact resistance between the AFM tip and the SiNW was put in evidence, and the SiNWs resistivity was estimated. PMID:21711623

Hydrogen ion microlithography

DOEpatents

Tsuo, Y. Simon; Deb, Satyen K.

1990-01-01

Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing.

Zinc-coordinated MOFs complexes regulated by hydrogen bonds: Synthesis, structure and luminescence study toward broadband white-light emission

NASA Astrophysics Data System (ADS)

Duan, Hui; Dan, Wenyan; Fang, Xiangdong

2018-04-01

Two new compounds, namely {[Zn(apc)2]·H2O}n (1) and [Zn(apc)2(H2O)2] (2), have been designed and synthesized with a multi-functional ligand 2-aminopyrimidine-5-carboxylic acid (Hapc). Both compounds were characterized by single crystal X-ray diffraction analysis (SC-XRD), elemental analysis (EA), infrared spectroscopy (IR), and thermogravimetric analysis (TG). In solid-state structures, 1 features a two-fold interpenetrating pillared-layer 3D framework with point symbol {83}2{86}, referring to tfa topology; while 2 exhibits a 3D framework based on super unit of Zn(apc)2(H2O)2 interconnected via hydrogen bonds. Furthermore, the luminescent properties of 1 and 2 were discussed.

The Liquid Annular Reactor System (LARS) propulsion

NASA Technical Reports Server (NTRS)

Powell, James; Ludewig, Hans; Horn, Frederick; Lenard, Roger

1990-01-01

A concept for very high specific impulse (greater than 2000 seconds) direct nuclear propulsion is described. The concept, termed the liquid annular reactor system (LARS), uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (approximately 6000 K). Operating pressure is moderate (approximately 10 atm), with the result that the outlet hydrogen is virtually 100 percent dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use seven rotating fuel elements, are beryllium moderated, and have critical radii of approximately 100 cm (core L/D approximately equal to 1.5).

Dynamics of Crust Dissolution and Gas Release in Tank 241-SY-101

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rassat, Scot D.; Stewart, Charles W.; Wells, Beric E.

2000-01-24

Due primarily to an increase in floating crust thickness, the waste level in Tank 241-SY-101 has grown appreciably and the flammable gas volume stored in the crust has become a potential hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from the nonconvective layer at the bottom of the tank, SY-101 will be diluted to dissolve a large fraction of the solids that allow the waste to retain gas. The plan is to transfer some waste out and back-dilute with water in several steps. In this work, mechanisms and rates of waste solidsmore » dissolution and gas releases are evaluated theoretically and experimentally. Particular emphasis is given to crust dissolution processes and associated gas releases, although dissolution and gas release from the mixed-slurry and nonconvective layers are also considered. The release of hydrogen gas to the tank domespace is modeled for a number of scenarios. Under the tank conditions expected at the time of back-dilution, no plausible continuous or sudden gas release scenarios resulting in flammable hydrogen concentrations were identified.« less

Probing hydrogen bonding in cocrystals and amorphous dispersions using (14)N-(1)H HMQC solid-state NMR.

PubMed

Tatton, Andrew S; Pham, Tran N; Vogt, Frederick G; Iuga, Dinu; Edwards, Andrew J; Brown, Steven P

2013-03-04

Cocrystals and amorphous solid dispersions have generated interest in the pharmaceutical industry as an alternative to more established solid delivery forms. The identification of intermolecular hydrogen bonding interactions in a nicotinamide palmitic acid cocrystal and a 50% w/w acetaminophen-polyvinylpyrrolidone solid dispersion are reported using advanced solid-state magic-angle spinning (MAS) NMR methods. The application of a novel (14)N-(1)H HMQC experiment, where coherence transfer is achieved via through-space couplings, is shown to identify specific hydrogen bonding motifs. Additionally, (1)H isotropic chemical shifts and (14)N electric field gradient (EFG) parameters, both accessible from (14)N-(1)H HMQC experiments, are shown to be sensitive to changes in hydrogen bonding geometry. Numerous indicators of molecular association are accessible from this experiment, including NH cross-peaks occurring from intermolecular hydrogen bonds and changes in proton chemical shifts or electric field gradient parameters. First-principles calculations using the GIPAW approach that yield accurate estimates of isotropic chemical shifts, and EFG parameters were used to assist in assignment. It is envisaged that (14)N-(1)H HMQC solid state NMR experiments could become a valuable screening technique of solid delivery forms in the pharmaceutical industry.

Effect of plasma nitriding on the structural stability and hydrogen absorption capability of Pd-coated Nb during thermal treatment

NASA Astrophysics Data System (ADS)

Ohtsu, Naofumi; Kozuka, Taro; Shibata, Yuga; Yamane, Misao

2017-11-01

Plasma nitriding was explored for improving the thermal stability of a composite hydrogen permeable membrane comprising a Pd coating on Nb substrate. A NbN intermediate layer was formed on the Nb substrate, and the progress of interdiffusion and deterioration of hydrogen absorption behavior after a thermal treatment at 573 and 773 K, respectively, were investigated. The intermediate layer significantly suppressed the interdiffusion between the coating and the substrate. Furthermore, an increase in the NbN concentration of the intermediate layer enhanced the suppression efficiency. However, the hydrogen permeability of the intermediate layer was significantly low, and hence, an increase in NbN concentration further decreased the hydrogen permeability. We concluded that the nitride layer with a high NbN content was unsuitable as an intermediate layer owing to its low hydrogen permeability, while the partial nitride layer with a low NbN content was inefficient in suppressing the interdiffusion.

Solid Hydrogen Experiments for Atomic Propellants

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan

2001-01-01

This paper illustrates experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Solid particles of hydrogen were frozen in liquid helium, and observed with a video camera. The solid hydrogen particle sizes, their molecular structure transitions, and their agglomeration times were estimated. article sizes of 1.8 to 4.6 mm (0.07 to 0. 18 in.) were measured. The particle agglomeration times were 0.5 to 11 min, depending on the loading of particles in the dewar. These experiments are the first step toward visually characterizing these particles, and allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

Phonons in quantum solids with defects. [lattice vacancies and interstitials in solid helium and metallic hydrogen

NASA Technical Reports Server (NTRS)

Jacobi, N.; Zmuidzinas, J. S.

1974-01-01

A formalism was developed for temperature-dependent, self-consistent phonons in quantum solids with defects. Lattice vacancies and interstitials in solid helium and metallic hydrogen, as well as electronic excitations in solid helium, were treated as defects that modify properties of these systems. The information to be gained from the modified phonon spectrum is discussed.

Zwitterionic 4-bromo-6-meth­oxy-2-{[tris­(hy­droxy­meth­yl)methyl]­iminiumyl­meth­yl}phenolate: crystal structure and Hirshfeld surface analysis

PubMed Central

Lee, See Mun; Lo, Kong Mun; Tan, Sang Loon; Tiekink, Edward R. T.

2016-01-01

In the solid state, the title compound, C12H16BrNO5 [systematic name: 4-bromo-2-((1E)-{[1,3-dihy­droxy-2-(hy­droxy­meth­yl)propan-2-yl]iminium­yl}meth­yl)-6-meth­oxy­benzen-1-olate], C12H16BrNO5, is found in the keto–amine tautomeric form, with an intra­molecular iminium-N—H⋯O(phenolate) hydrogen bond and an E conformation about the C=N bond. Both gauche (two) and anti relationships are found for the methyl­hydroxy groups. In the crystal, a supra­molecular layer in the bc plane is formed via hy­droxy-O—H⋯O(hy­droxy) and charge-assisted hy­droxy-O—H⋯O(phenolate) hydrogen-bonding inter­actions; various C—H⋯O inter­actions provide additional cohesion to the layers, which stack along the a axis with no directional inter­actions between them. A Hirshfeld surface analysis confirms the lack of specific inter­actions in the inter-layer region. PMID:27536419

Variable Density Multilayer Insulation for Cryogenic Storage

NASA Technical Reports Server (NTRS)

Hedayat, A.; Brown, T. M.; Hastings, L. J.; Martin, J.

2000-01-01

Two analytical models for a foam/Variable Density Multi-Layer Insulation (VD-MLI) system performance are discussed. Both models are one-dimensional and contain three heat transfer mechanisms, namely conduction through the spacer material, radiation between the shields, and conduction through the gas. One model is based on the methodology developed by McIntosh while the other model is based on the Lockheed semi-empirical approach. All models input variables are based on the Multi-purpose Hydrogen Test Bed (MHTB) geometry and available values for material properties and empirical solid conduction coefficient. Heat flux predictions are in good agreement with the MHTB data, The heat flux predictions are presented for the foam/MLI combinations with 30, 45, 60, and 75 MLI layers

Thin-film metal hydrides.

PubMed

Remhof, Arndt; Borgschulte, Andreas

2008-12-01

The goal of the medieval alchemist, the chemical transformation of common metals into nobel metals, will forever be a dream. However, key characteristics of metals, such as their electronic band structure and, consequently, their electric, magnetic and optical properties, can be tailored by controlled hydrogen doping. Due to their morphology and well-defined geometry with flat, coplanar surfaces/interfaces, novel phenomena may be observed in thin films. Prominent examples are the eye-catching hydrogen switchable mirror effect, the visualization of solid-state diffusion and the formation of complex surface morphologies. Thin films do not suffer as much from embrittlement and/or decrepitation as bulk materials, allowing the study of cyclic absorption and desorption. Therefore, thin-metal hydride films are used as model systems to study metal-insulator transitions, for high throughput combinatorial research or they may be used as indicator layers to study hydrogen diffusion. They can be found in technological applications as hydrogen sensors, in electrochromic and thermochromic devices. In this review, we discuss the effect of hydrogen loading of thin niobium and yttrium films as archetypical examples of a transition metal and a rare earth metal, respectively. Our focus thereby lies on the hydrogen induced changes of the electronic structure and the morphology of the thin films, their optical properties, the visualization and the control of hydrogen diffusion and on the study of surface phenomena and catalysis.

Hydrogen ion microlithography

DOEpatents

Tsuo, Y.S.; Deb, S.K.

1990-10-02

Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing. 6 figs.

Direct Evidence for Solid-like Hydrogen in a Nanoporous Carbon Hydrogen Storage Material at Supercritical Temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ting, Valeska P.; Ramirez-Cuesta, Anibal J.; Bimbo, Nuno

Here in this paper we report direct physical evidence that confinement of molecular hydrogen (H 2) in an optimized nanoporous carbon results in accumulation of hydrogen with characteristics commensurate with solid H 2 at temperatures up to 67 K above the liquid vapor critical temperature of bulk H 2. This extreme densification is attributed to confinement of 112 molecules in the optimally sized micropores, and occurs at pressures as low as 0.02 MPa. The quantities of contained, solid-like H 2 increased with pressure and were directly evaluated using in situ inelastic neutron scattering and confirmed by analysis of gas sorptionmore » isotherms. The demonstration of the existence of solid-like H 2 challenges the existing assumption that supercritical hydrogen confined in nanopores has an upper limit of liquid H 2 density. Thus, this insight offers opportunities for the development of more accurate models for the evaluation and design of nanoporous materials for high capacity adsorptive hydrogen storage.« less

Direct Evidence for Solid-like Hydrogen in a Nanoporous Carbon Hydrogen Storage Material at Supercritical Temperatures

DOE PAGES

Ting, Valeska P.; Ramirez-Cuesta, Anibal J.; Bimbo, Nuno; ...

2015-07-14

Here in this paper we report direct physical evidence that confinement of molecular hydrogen (H 2) in an optimized nanoporous carbon results in accumulation of hydrogen with characteristics commensurate with solid H 2 at temperatures up to 67 K above the liquid vapor critical temperature of bulk H 2. This extreme densification is attributed to confinement of 112 molecules in the optimally sized micropores, and occurs at pressures as low as 0.02 MPa. The quantities of contained, solid-like H 2 increased with pressure and were directly evaluated using in situ inelastic neutron scattering and confirmed by analysis of gas sorptionmore » isotherms. The demonstration of the existence of solid-like H 2 challenges the existing assumption that supercritical hydrogen confined in nanopores has an upper limit of liquid H 2 density. Thus, this insight offers opportunities for the development of more accurate models for the evaluation and design of nanoporous materials for high capacity adsorptive hydrogen storage.« less

Properties of Surface-Modification Layer Generated by Atomic Hydrogen Annealing on Poly(ethylene naphthalate) Substrate

NASA Astrophysics Data System (ADS)

Heya, Akira; Matsuo, Naoto

2008-01-01

The surface of a poly(ethylene naphthalate) (PEN) substrate was modified by atomic hydrogen annealing (AHA). In this method, a PEN substrate was exposed to atomic hydrogen generated by cracking hydrogen molecules on heated tungsten wire. The properties of the surface-modification layer by AHA were evaluated by spectroscopic ellipsometry. It is found that the thickness of the modified layer was 5 nm and that the modification layer has a low refractive index compared with the PEN substrate. The modification layer relates to the reduction reaction of the PEN substrate by AHA.

Tailoring gadolinium-doped ceria-based solid oxide fuel cells to achieve 2 W cm(-2) at 550 °C.

PubMed

Lee, Jin Goo; Park, Jeong Ho; Shul, Yong Gun

2014-06-04

Low-temperature operation is necessary for next-generation solid oxide fuel cells due to the wide variety of their applications. However, significant increases in the fuel cell losses appear in the low-temperature solid oxide fuel cells, which reduce the cell performance. To overcome this problem, here we report Gd0.1Ce0.9O1.95-based low-temperature solid oxide fuel cells with nanocomposite anode functional layers, thin electrolytes and core/shell fibre-structured Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Gd0.1Ce0.9O1.95 cathodes. In particular, the report describes the use of the advanced electrospinning and Pechini process in the preparation of the core/shell-fibre-structured cathodes. The fuel cells show a very high performance of 2 W cm(-2) at 550 °C in hydrogen, and are stable for 300 h even under the high current density of 1 A cm(-2). Hence, the results suggest that stable and high-performance solid oxide fuel cells at low temperatures can be achieved by modifying the microstructures of solid oxide fuel cell components.

Solid Hydrogen Experiments for Atomic Propellants: Particle Formation Energy and Imaging Analyses

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan

2002-01-01

This paper presents particle formation energy balances and detailed analyses of the images from experiments that were conducted on the formation of solid hydrogen particles in liquid helium during the Phase II testing in 2001. Solid particles of hydrogen were frozen in liquid helium and observed with a video camera. The solid hydrogen particle sizes and the total mass of hydrogen particles were estimated. The particle formation efficiency is also estimated. Particle sizes from the Phase I testing in 1999 and the Phase II testing in 2001 were similar. Though the 2001 testing created similar particles sizes, many new particle formation phenomena were observed. These experiment image analyses are one of the first steps toward visually characterizing these particles and it allows designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

FLUSH: A tool for the design of slush hydrogen flow systems

NASA Technical Reports Server (NTRS)

Hardy, Terry L.

1990-01-01

As part of the National Aerospace Plane Project an analytical model was developed to perform calculations for in-line transfer of solid-liquid mixtures of hydrogen. This code, called FLUSH, calculates pressure drop and solid fraction loss for the flow of slush hydrogen through pipe systems. The model solves the steady-state, one-dimensional equation of energy to obtain slush loss estimates. A description of the code is provided as well as a guide for users of the program. Preliminary results are also presented showing the anticipated degradation of slush hydrogen solid content for various piping systems.

Phase Transition of H 2 in Subnanometer Pores Observed at 75 K

DOE PAGES

Olsen, Raina J.; Gillespie, Andrew K.; Contescu, Cristian I.; ...

2017-10-30

In this paper, we report a phase transition in H 2 adsorbed in a locally graphitic Saran carbon with subnanometer pores 0.5–0.65 nm in width, in which two layers of hydrogen can just barely squeeze, provided they pack tightly. The phase transition is observed at 75 K, temperatures far higher than other systems in which an adsorbent is known to increase phase transition temperatures: for instance, H 2 melts at 14 K in the bulk, but at 20 K on graphite because the solid H 2 is stabilized by the surface structure. Here we observe a transition at 75 Kmore » and 77–200 bar: from a low-temperature, low-density phase to a high-temperature, higher density phase. We model the low-density phase as a monolayer commensurate solid composed mostly of para-H 2 (the ground nuclear spin state, S = 0) and the high-density phase as an orientationally ordered bilayer commensurate solid composed mostly of ortho-H 2 (S = 1). We attribute the increase in density with temperature to the fact that the oblong ortho-H 2 can pack more densely. The transition is observed using two experiments. The high-density phase is associated with an increase in neutron backscatter by a factor of 7.0 ± 0.1. Normally, hydrogen produces no backscatter (scattering angle >90°). This backscatter appears along with a discontinuous increase in the excitation mass from 1.2 amu to 21.0 ± 2.3 amu, which we associate with collective nuclear spin excitations in the orientationally ordered phase. Film densities were measured using hydrogen adsorption. Finally, no phase transition was observed in H 2 adsorbed in control activated carbon materials.« less

Phase Transition of H 2 in Subnanometer Pores Observed at 75 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olsen, Raina J.; Gillespie, Andrew K.; Contescu, Cristian I.

In this paper, we report a phase transition in H 2 adsorbed in a locally graphitic Saran carbon with subnanometer pores 0.5–0.65 nm in width, in which two layers of hydrogen can just barely squeeze, provided they pack tightly. The phase transition is observed at 75 K, temperatures far higher than other systems in which an adsorbent is known to increase phase transition temperatures: for instance, H 2 melts at 14 K in the bulk, but at 20 K on graphite because the solid H 2 is stabilized by the surface structure. Here we observe a transition at 75 Kmore » and 77–200 bar: from a low-temperature, low-density phase to a high-temperature, higher density phase. We model the low-density phase as a monolayer commensurate solid composed mostly of para-H 2 (the ground nuclear spin state, S = 0) and the high-density phase as an orientationally ordered bilayer commensurate solid composed mostly of ortho-H 2 (S = 1). We attribute the increase in density with temperature to the fact that the oblong ortho-H 2 can pack more densely. The transition is observed using two experiments. The high-density phase is associated with an increase in neutron backscatter by a factor of 7.0 ± 0.1. Normally, hydrogen produces no backscatter (scattering angle >90°). This backscatter appears along with a discontinuous increase in the excitation mass from 1.2 amu to 21.0 ± 2.3 amu, which we associate with collective nuclear spin excitations in the orientationally ordered phase. Film densities were measured using hydrogen adsorption. Finally, no phase transition was observed in H 2 adsorbed in control activated carbon materials.« less

Structural and kinetic studies of metal hydride hydrogen storage materials using thin film deposition and characterization techniques

NASA Astrophysics Data System (ADS)

Kelly, Stephen Thomas

Hydrogen makes an attractive energy carrier for many reasons. It is an abundant chemical fuel that can be produced from a wide variety of sources and stored for very long periods of time. When used in a fuel cell, hydrogen emits only water at the point of use, making it very attractive for mobile applications such as in an automobile. Metal hydrides are promising candidates for on-board reversible hydrogen storage in mobile applications due to their very high volumetric storage capacities---in most cases exceeding even that of liquid hydrogen. The United States Department of Energy (DOE) has set fuel system targets for an automotive hydrogen storage system, but as of yet no single material meets all the requirements. In particular, slow reaction kinetics and/or inappropriate thermodynamics plague many metal hydride hydrogen storage materials. In order to engineer a practical material that meets the DOE targets, we need a detailed understanding of the kinetic and thermodynamic properties of these materials during the phase change. In this work I employed sputter deposited thin films as a platform to study materials with highly controlled chemistry, microstructure and catalyst placement using thin film characterization techniques such as in situ x-ray diffraction (XRD) and neutron reflectivity. I observed kinetic limitations in the destabilized Mg2Si system due to the slow diffusion of the host Mg and Si atoms while forming separate MgH2 and Si phases. Conversely, I observed that the presence of Al in the Mg/Al system inhibits hydrogen diffusion while the host Mg and Al atoms interdiffuse readily, allowing the material to fall into a kinetic and/or thermodynamic trap by forming intermetallic compounds such as Mg17Al 12. By using in situ XRD to analyze epitaxial Mg films grown on (001) oriented Al2O3 substrates I observed hydride growth consistent with a model of a planar hydride layer growing into an existing metal layer. Subsequent film cycling changes the hydrogen absorption and desorption kinetics and degrades the material texture. Cycling the films to greater hydrogen loading accelerates the changes to the kinetics and material texture. In addition to in situ XRD experiments, in situ neutron reflectivity experiments on epitaxial Mg films exposed to hydrogen gas reveal details about the microstructural development of the growing hydride layer as the film absorbs and releases hydrogen. Small (10 wt%) additions of Ti to epitaxial Mg films during growth result in metastable solid solution films of Ti in Mg that deposit epitaxially on (001) Al2O3 substrates with epitaxy similar to the pure Mg films. These metastable alloy films absorb hydrogen faster than pure Mg films under identical conditions. Subsequent film cycling results in altered reaction kinetics and a transition to a different kinetic mechanism during desorption than for pure Mg films.

Chemical storage of hydrogen in few-layer graphene

PubMed Central

Subrahmanyam, K. S.; Kumar, Prashant; Maitra, Urmimala; Govindaraj, A.; Hembram, K. P. S. S.; Waghmare, Umesh V.; Rao, C. N. R.

2011-01-01

Birch reduction of few-layer graphene samples gives rise to hydrogenated samples containing up to 5 wt % of hydrogen. Spectroscopic studies reveal the presence of sp3 C-H bonds in the hydrogenated graphenes. They, however, decompose readily on heating to 500 °C or on irradiation with UV or laser radiation releasing all the hydrogen, thereby demonstrating the possible use of few-layer graphene for chemical storage of hydrogen. First-principles calculations throw light on the mechanism of dehydrogenation that appears to involve a significant reconstruction and relaxation of the lattice. PMID:21282617

Solid hydrogen coated graphite particles in the interstellar medium. I.

NASA Technical Reports Server (NTRS)

Swamy, K. S. K.; Wickramasinghe, N. C.

1969-01-01

Solid para hydrogen coated graphite particles expulsion into interstellar medium from star formation regions, considering mantles stability and particles extinction efficiency, albedo and phase function

All-Diamond Microelectrodes as Solid State Probes for Localized Electrochemical Sensing.

PubMed

Silva, Eduardo L; Gouvêa, Cristol P; Quevedo, Marcela C; Neto, Miguel A; Archanjo, Braulio S; Fernandes, António J S; Achete, Carlos A; Silva, Rui F; Zheludkevich, Mikhail L; Oliveira, Filipe J

2015-07-07

The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron-hydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al-Cu-CFRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell.

Hydrogen pickup mechanism of zirconium alloys

NASA Astrophysics Data System (ADS)

Couet, Adrien

Although the optimization of zirconium based alloys has led to significant improvements in hydrogen pickup and corrosion resistance, the mechanisms by which such alloy improvements occur are still not well understood. In an effort to understand such mechanisms, a systematic study of the alloy effect on hydrogen pickup is conducted, using advanced characterization techniques to rationalize precise measurements of hydrogen pickup. The hydrogen pick-up fraction is accurately measured for a specially designed set of commercial and model alloys to investigate the effects of alloying elements, microstructure and corrosion kinetics on hydrogen uptake. Two different techniques to measure hydrogen concentrations were used: a destructive technique, Vacuum Hot Extraction, and a non-destructive one, Cold Neutron Prompt Gamma Activation Analysis. The results indicate that hydrogen pickup varies not only from alloy to alloy but also during the corrosion process for a given alloy. For instance Zircaloy type alloys show high hydrogen pickup fraction and sub-parabolic oxidation kinetics whereas ZrNb alloys show lower hydrogen pickup fraction and close to parabolic oxidation kinetics. Hypothesis is made that hydrogen pickup result from the need to balance charge during the corrosion reaction, such that the pickup of hydrogen is directly related to (and indivisible of) the corrosion mechanism and decreases when the rate of electron transport or oxide electronic conductivity sigmao xe through the protective oxide increases. According to this hypothesis, alloying elements (either in solid solution or in precipitates) embedded in the oxide as well as space charge variations in the oxide would impact the hydrogen pick-up fraction by modifying sigmaox e, which drives oxidation and hydriding kinetics. Dedicated experiments and modelling were performed to assess and validate these hypotheses. In-situ electrochemical impedance spectroscopy (EIS) experiments were performed on Zircaloy-4 tubes to directly measure the evolution of sigma oxe as function of exposure time. The results show that sigmao xe decreases as function of exposure time and that its variations are directly correlated to the instantaneous hydrogen pickup fraction variations. The electron transport through the oxide layer is thus altered as the oxide grows, reasons for which are yet to be exactly determined. Preliminary results also show that sigma oxe of ZrNb alloys would be much higher compared with Zircaloy-4. Thus, it is confirmed that sigmaox e is a key parameter in the hydrogen and oxidation mechanism. Because the mechanism whereby alloying elements are incorporated into the oxide layer is critical to changing sigmao xe, the evolution of the oxidation state of two common alloying elements, Fe and Nb, when incorporated into the growing oxide layers is investigated using X-Ray Absorption Near-Edge Spectroscopy (XANES) using micro-beam synchrotron radiation on cross sectional oxide samples. The results show that the oxidation of both Fe and Nb is delayed in the oxide layer compared to that of Zr, and that this oxidation delay is related to the variations of the instantaneous hydrogen pick-up fraction with exposure time. The evolution of Nb oxidation as function of oxide depth is also compatible with space charge compensation in the oxide and with an increase in sigmaox e of ZrNb alloys compared to Zircaloys. Finally, various successively complex models from the well-known Wagner oxidation theory to the more complex effect of space charge on oxidation kinetics have been developed. The general purpose of the modeling effort is to provide a rationale for the sub-parabolic oxidation kinetics and demonstrate the correlation with hydrogen pickup fraction. It is directly demonstrated that parabolic oxidation kinetics is associated with high sigmao xe and low space charges in the oxide whereas sub-parabolic oxidation kinetics is associated with lower sigmaox e and higher space charge in the oxide. All these observations helped us to propose a general corrosion mechanism of zirconium alloys involving both oxidation and hydrogen pickup mechanism to better understand and predict the effect of alloying additions on the behavior of zirconium alloys.

Analysis of quasi-hybrid solid rocket booster concepts for advanced earth-to-orbit vehicles

NASA Technical Reports Server (NTRS)

Zurawski, Robert L.; Rapp, Douglas C.

1987-01-01

A study was conducted to assess the feasibility of quasi-hybrid solid rocket boosters for advanced Earth-to-orbit vehicles. Thermochemical calculations were conducted to determine the effect of liquid hydrogen addition, solids composition change plus liquid hydrogen addition, and the addition of an aluminum/liquid hydrogen slurry on the theoretical performance of a PBAN solid propellant rocket. The space shuttle solid rocket booster was used as a reference point. All three quasi-hybrid systems theoretically offer higher specific impulse when compared with the space shuttle solid rocket boosters. However, based on operational and safety considerations, the quasi-hybrid rocket is not a practical choice for near-term Earth-to-orbit booster applications. Safety and technology issues pertinent to quasi-hybrid rocket systems are discussed.

Cooling by conversion of para to ortho-hydrogen

NASA Technical Reports Server (NTRS)

Sherman, A. (Inventor)

1983-01-01

The cooling capacity of a solid hydrogen cooling system is significantly increased by exposing vapor created during evaporation of a solid hydrogen mass to a catalyst and thereby accelerating the endothermic para-to-ortho transition of the vapor to equilibrium hydrogen. Catalyst such as nickel, copper, iron or metal hydride gels of films in a low pressure drop catalytic reactor are suitable for accelerating the endothermic para-to-ortho conversion.

Supramolecular assemblies of tetrafluoroterephthalic acid and N-heterocycles via various strong hydrogen bonds and weak Csbnd H⋯F interactions: Synthons cooperation, robust motifs and structural diversity

NASA Astrophysics Data System (ADS)

Hu, Yanjing; Hu, Hanbin; Li, Yingying; Chen, Ruixin; Yang, Yu; Wang, Lei

2016-10-01

A series of organic solid states including three salts, two co-crystals, and three hydrates based on tetrafluoroterephthalic acid (H2tfBDC) and N-bearing ligands (2,4-(1H,3H)-pyrimidine dione (PID), 2,4-dihydroxy-6-methyl pyrimidine (DHMPI), 2-amino-4,6-dimethyl pyrimidine (ADMPI), 2-amino-4,6-dimenthoxy pyrimidine (ADMOPI), 5,6-dimenthyl benzimidazole (DMBI), 2-aminobenzimidazole (ABI), 3,5-dimethyl pyrazole (DMP), and 3-cyanopyridine (3-CNpy)), namely, [(PID)2·(H2tfBDC)] (1), [(DHMPI)2·(H2tfBDC)] (2), [(H-ADMPI+)2·(tfBDC2-)·2(H2O)] (3), [(H-ADMOPI+)2·(tfBDC2-)·(H2O)] (4), [(H-DMBI+)2·(tfBDC2-)·2(H2O)] (5), [(H-ABI+)2·(tfBDC2-)] (6), [(H-DMP+)·(HtfBDC-)] (7), and [(H-3-CNpy+)·(HtfBDC-)] (8), were synthesized by solvent evaporation method. Crystal structures analyses show that the F atom of the H2tfBDC participates in multiple Csbnd H⋯F hydrogen bond formations, producing different supramolecular synthons. The weak hydrogen bonding Csbnd H⋯F and Nsbnd H⋯F play an important part in constructing the diversity structures 2-8, except in crystal 1. In complexes 1-3, they present the same synthon R22(8) with different N-heterocyclic compounds, which may show the strategy in constructing the supramolecular. Meanwhile, the complex 3 exhibits a 2D layer, and the independent molecules of water exist in the adjacent layers. In complexes 4 and 5, the water molecules connect the neighboring layers to form 3D network by strong Osbnd H⋯O hydrogen bonding. These crystals 1-8 were fully characterized by single-crystal X-ray crystallography, elemental analysis, infrared spectroscopy (IR), and thermogravimetric analysis (TGA).

Porous framework of T{sub 2}[Fe(CN){sub 6}].xH{sub 2}O with T=Co, Ni, Cu, Zn, and H{sub 2} storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avila, M.; Reguera, L.; Rodriguez-Hernandez, J.

2008-11-15

The materials under study were prepared from aqueous solutions of ferrocyanic acid and salts of the involved transition metals and their crystal structure solved and refined from X-ray powder diffraction data. Complementary information from thermogravimetric, infrared and Moessbauer data was also used for the structural study. Three different crystal structures were found: hexagonal (P-3) for Zn with the zinc atom coordinated to three N ends of CN groups plus a water molecule, cubic (Pm-3m) for Ni and Cu, and monoclinic (P2{sub 1}/m) for Co. For Ni and Cu the obtained solids have an open channel framework related to 50% ofmore » vacancies for the building unit, [Fe(CN){sub 6}]. In the as-synthesized material the framework free volume is occupied by coordinated and hydrogen-bonded water molecules. These of hexacyanoferrates (II) have received certain attention as prototype of materials for the hydrogen storage. In the anhydrous phase of Ni and Cu, 50% of the metal (T) coordination sites, located at the cavities surface, will be available to interact with the hydrogen molecule. However, when the crystal waters are removed the porous frameworks collapse as it is suggested by H{sub 2} and CO{sub 2} adsorption data. For Co, a structure of stacked layers was found where the cobalt atoms have both tetrahedral and octahedral coordination. The layers remain together through a network of hydrogen-bonding interactions between coordinated and weakly bonded water molecules. No H{sub 2} adsorption was observed in the anhydrous phase of Co. For Zn, the porous framework remains stable on the water removal but with a system of narrow channels and a small available volume, also inaccessible to H{sub 2}. - Graphical abstract: Structure of stacked layers for CO{sub 2}[Fe(CN){sub 6}].xH{sub 2}O.« less

Hydrogen combustion in a flat semi-confined layer with respect to the Fukushima Daiichi accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuznetsov, M.; Yanez, J.; Grune, J.

2012-07-01

The hydrogen accumulation at the top of containment or reactor building may occur due to an interaction of molten corium and water followed by a severe accident of a nuclear reactor (TMI, Chernobyl, Fukushima Daiichi). The hydrogen, released from the reactor, accumulates usually as a stratified semi-confined layer of hydrogen-air mixture. A series of large scale experiments on hydrogen combustion and explosion in a semi-confined layer of uniform and non-uniform hydrogen-air mixtures in presence of obstructions or without them was performed at the Karlsruhe Inst. of Technology (KIT). Different flame propagation regimes from slow subsonic to relative fast sonic flamesmore » and then to the detonations were experimentally investigated in different geometries and then simulated with COMSD code with respect to evaluate amount of burnt hydrogen taken place during the Fukushima Daiichi Accident (FDA). The experiments were performed in a horizontal semi-confined layer with dimensions of 9x3x0.6 m with/without obstacles opened from below. The hydrogen concentration in the mixtures with air was varied in the range of 0-34 vol. % without or with a gradient of 0-60 vol. %H{sub 2}/m. Effects of hydrogen concentration gradient, thickness of the layer, geometry of the obstructions, average and maximum hydrogen concentration on flame propagation regimes were investigated with respect to evaluate the maximum pressure loads of internal structures. Blast wave strength and dynamics of propagation after explosion of the layer of hydrogen-air mixture was numerically simulated to reproduce the hydrogen explosion process during the Fukushima Daiichi Accident. (authors)« less

Controlled drive-in and precipitation of hydrogen during plasma hydrogenation of silicon using a thin compressively strained SiGe layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okba, F.; Departement Optique et Mecanique de Precision, Faculte des Sciences de l'Ingenieur, Universite Ferhat Abbas, Setif 19000; Cherkashin, N.

2010-07-19

We have quantitatively studied by transmission electron microscopy the growth kinetics of platelets formed during the continuous hydrogenation of a Si substrate/SiGe/Si heterostructure. We have evidenced and explained the massive transfer of hydrogen from a population of platelets initially generated in the upper Si layer by plasma hydrogenation towards a population of larger platelets located in the SiGe layer. We demonstrate that this type of process can be used not only to precisely localize the micro-cracks, then the fracture line at a given depth but also to 'clean' the top layer from pre-existing defects.

The role of hydrogen in zirconium alloy corrosion

NASA Astrophysics Data System (ADS)

Ensor, B.; Lucente, A. M.; Frederick, M. J.; Sutliff, J.; Motta, A. T.

2017-12-01

Hydrogen enters zirconium metal as a result of the corrosion process and forms hydrides when present in quantities above the solubility limit at a given temperature. Zircaloy-4 coupons of different thicknesses (0.4 mm-2.3 mm) but identical chemistry and processing were corroded in autoclave at 360 °C for various times up to 2800 days. Coupons were periodically removed and weighed to determine weight gain, which allows follow of the corrosion kinetics. Coupon thickness differences resulted in different volumetric concentrations of hydrogen, as quantified using hot vacuum extraction. The thinnest coupons, having the highest concentration of hydrogen, demonstrated acceleration in their corrosion kinetics and shorter transition times when compared to thicker coupons. Furthermore, it was seen that the post-transition corrosion rate was increased with increasing hydrogen concentration. Corrosion rates increased only after the terminal solid solubility (TSS) was exceeded for hydrogen in Zircaloy-4 at 360 °C. Therefore, it is hypothesized that the corrosion acceleration is caused by the formation of hydrides. Scanning electron microscope (SEM) examinations of fractured oxide layers demonstrate the oxide morphology changed with hydrogen content, with more equiaxed oxide grains in the high hydrogen samples than in those with lower hydrogen content. Additionally, locations of advanced oxide growth were correlated with locations of hydrides in the metal. A hypothesis is proposed to explain the accelerated corrosion due to the presence of the hydrides, namely that the metal, locally, is less able to accommodate oxide growth stresses and this leads to earlier loss of oxide protectiveness in the form of more frequent oxide kinetic transitions.

Communication—Electrolysis at High Efficiency with Remarkable Hydrogen Production Rates

DOE PAGES

Wood, Anthony; He, Hongpeng; Joia, Tahir; ...

2016-01-20

Solid Oxide Electrolysis (SOE) can be used to produce hydrogen with very high efficiencies at remarkable hydrogen production rates. Through microstructural and compositional modification, conventional low cost Solid Oxide Fuel Cell (SOFC) materials have been used to create a Solid Oxide Electrolysis Cell (SOEC) that can achieve remarkable current density at cell voltages allowing higher conversion efficiency than current commercial electrolysers. Current densities in excess of 6 A/cm2 have been achieved at 800°C with a cell voltage of < 1.67 V. This cell shows a more than 3-fold increase in hydrogen production rate at higher efficiency than established commercial electrolysers.

A novel accelerated oxidative stability screening method for pharmaceutical solids.

PubMed

Zhu, Donghua Alan; Zhang, Geoff G Z; George, Karen L S T; Zhou, Deliang

2011-08-01

Despite the fact that oxidation is the second most frequent degradation pathway for pharmaceuticals, means of evaluating the oxidative stability of pharmaceutical solids, especially effective stress testing, are still lacking. This paper describes a novel experimental method for peroxide-mediated oxidative stress testing on pharmaceutical solids. The method utilizes urea-hydrogen peroxide, a molecular complex that undergoes solid-state decomposition and releases hydrogen peroxide vapor at elevated temperatures (e.g., 30°C), as a source of peroxide. The experimental setting for this method is simple, convenient, and can be operated routinely in most laboratories. The fundamental parameter of the system, that is, hydrogen peroxide vapor pressure, was determined using a modified spectrophotometric method. The feasibility and utility of the proposed method in solid form selection have been demonstrated using various solid forms of ephedrine. No degradation was detected for ephedrine hydrochloride after exposure to the hydrogen peroxide vapor for 2 weeks, whereas both anhydrate and hemihydrate free base forms degraded rapidly under the test conditions. In addition, both the anhydrate and the hemihydrate free base degraded faster when exposed to hydrogen peroxide vapor at 30°C under dry condition than at 30°C/75% relative humidity (RH). A new degradation product was also observed under the drier condition. The proposed method provides more relevant screening conditions for solid dosage forms, and is useful in selecting optimal solid form(s), determining potential degradation products, and formulation screening during development. Copyright © 2011 Wiley-Liss, Inc.

Quantitative analysis of hydrogen in SiO{sub 2}/SiN/SiO{sub 2} stacks using atom probe tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunimune, Yorinobu, E-mail: yorinobu.kunimune.vz@renesas.com; Shimada, Yasuhiro; Sakurai, Yusuke

2016-04-15

We have demonstrated that it is possible to reproducibly quantify hydrogen concentration in the SiN layer of a SiO{sub 2}/SiN/SiO{sub 2} (ONO) stack structure using ultraviolet laser-assisted atom probe tomography (APT). The concentration of hydrogen atoms detected using APT increased gradually during the analysis, which could be explained by the effect of hydrogen adsorption from residual gas in the vacuum chamber onto the specimen surface. The amount of adsorbed hydrogen in the SiN layer was estimated by analyzing another SiN layer with an extremely low hydrogen concentration (<0.2 at. %). Thus, by subtracting the concentration of adsorbed hydrogen, the actualmore » hydrogen concentration in the SiN layer was quantified as approximately 1.0 at. %. This result was consistent with that obtained by elastic recoil detection analysis (ERDA), which confirmed the accuracy of the APT quantification. The present results indicate that APT enables the imaging of the three-dimensional distribution of hydrogen atoms in actual devices at a sub-nanometer scale.« less

FLUSH - PREDICTION OF FLOW PARAMETERS OF SLUSH HYDROGEN

NASA Technical Reports Server (NTRS)

Hardy, T.

1994-01-01

Slush hydrogen, a mixture of the solid and liquid phases of hydrogen, is a possible source of fuel for the National Aerospace Plane (NASP) Project. Advantages of slush hydrogen over liquid hydrogen include greater heat capacity and greater density. However, practical use of slush hydrogen as a fuel requires systems of lines, valves, etc. which are designed to deliver the fuel in slush form with minimal solid loss as a result of pipe heating or flow friction. Engineers involved with the NASP Project developed FLUSH to calculate the pressure drop and slush hydrogen solid fraction loss for steady-state, one-dimensional flow. FLUSH solves the steady-state, one-dimensional energy equation and the Bernoulli equation for pipe flow. The program performs these calculations for each two-node element--straight pipe length, elbow, valve, fitting, or other part of the piping system--specified by the user. The user provides flow rate, upstream pressure, initial solid hydrogen fraction, element heat leak, and element parameters such as length and diameter. For each element, FLUSH first calculates the pressure drop, then figures the slush solid fraction exiting the element. The code employs GASPLUS routines to calculate thermodynamic properties for the slush hydrogen. FLUSH is written in FORTRAN IV for DEC VAX series computers running VMS. An executable is provided on the tape. The GASPLUS physical properties routines which are required for building the executable are included as one object library on the program media (full source code for GASPLUS is available separately as COSMIC Program Number LEW-15091). FLUSH is available in DEC VAX BACKUP format on a 9-track 1600 BPI magnetic tape (standard media) or on a TK50 tape cartridge. FLUSH was developed in 1989.

New Propellants and Cryofuels

NASA Technical Reports Server (NTRS)

Palasezski, Bryan; Sullivan, Neil S.; Hamida, Jaha; Kokshenev, V.

2006-01-01

The proposed research will investigate the stability and cryogenic properties of solid propellants that are critical to NASA s goal of realizing practical propellant designs for future spacecraft. We will determine the stability and thermal properties of a solid hydrogen-liquid helium stabilizer in a laboratory environment in order to design a practical propellant. In particular, we will explore methods of embedding atomic species and metallic nano-particulates in hydrogen matrices suspended in liquid helium. We will also measure the characteristic lifetimes and diffusion of atomic species in these candidate cryofuels. The most promising large-scale advance in rocket propulsion is the use of atomic propellants; most notably atomic hydrogen stabilized in cryogenic environments, and metallized-gelled liquid hydrogen (MGH) or densified gelled hydrogen (DGH). The new propellants offer very significant improvements over classic liquid oxygen/hydrogen fuels because of two factors: (1) the high energy-release, and (ii) the density increase per unit energy release. These two changes can lead to significant reduced mission costs and increased payload to orbit weight ratios. An achievable 5 to 10 percent improvement in specific impulse for the atomic propellants or MGH fuels can result in a doubling or tripling of system payloads. The high-energy atomic propellants must be stored in a stabilizing medium such as solid hydrogen to inhibit or delay their recombination into molecules. The goal of the proposed research is to determine the stability and thermal properties of the solid hydrogen-liquid helium stabilizer. Magnetic resonance techniques will be used to measure the thermal lifetimes and the diffusive motions of atomic species stored in solid hydrogen grains. The properties of metallic nano-particulates embedded in hydrogen matrices will also be studied and analyzed. Dynamic polarization techniques will be developed to enhance signal/noise ratios in order to be able to detect low concentrations of the introduced species. The required lifetimes for atomic hydrogen and other species can only be realized at low temperatures to avoid recombination of atoms before use as a fuel.

Effects of hydrogen on thermal creep behaviour of Zircaloy fuel cladding

NASA Astrophysics Data System (ADS)

Suman, Siddharth; Khan, Mohd Kaleem; Pathak, Manabendra; Singh, R. N.

2018-01-01

Zirconium alloys are extensively used for nuclear fuel cladding. Creep is one of the most likely degradation mechanisms for fuel cladding during reactor operating and repository conditions. Fuel cladding tubes undergo waterside corrosion during service and hydrogen is produced as a result of it-a fraction of which is picked up by cladding. Hydrogen remains in solid solution up to terminal solid solubility and it precipitates as brittle hydride phase in the zirconium metal matrix beyond this limiting concentration. Hydrogen, either in solid solution or as precipitated hydride, alters the creep behaviour of zirconium alloys. The present article critically reviews the influence of hydrogen on thermal creep behaviour of zirconium alloys, develops the systematic understanding of this multifaceted phenomenon, and delineates the thrust areas which require further investigations.

Gradiently Polymerized Solid Electrolyte Meets with Micro/Nano-Structured Cathode Array.

PubMed

Dong, Wei; Zeng, Xian-Xiang; Zhang, Xu-Dong; Li, Jin-Yi; Shi, Ji-Lei; Xiao, Yao; Shi, Yang; Wen, Rui; Yin, Ya-Xia; Wang, Tai-Shan; Wang, Chun-Ru; Guo, Yu-Guo

2018-05-02

The poor contact between the solid-state electrolyte and cathode materials leads to high interfacial resistance, severely limiting the rate capability of solid Li metal batteries. Herein, an integrative battery design is introduced with a gradiently polymerized solid electrolyte (GPSE), a micro-channel current collector array and nano-sized cathode particles. In-situ formed GPSE encapsulates cathode nanoparticles in the micro-channel with ductile inclusions to lower interfacial impedance, and the stiff surface layer of GPSE toward anode suppresses Li dendrites growth. Li metal batteries based on GPSE and Li-free hydrogenated V2O5 (V2O5-H) cathode exhibit an outstanding high-rate response of up to 5 C (the capacity ratio of 5 C / 1 C is 90.3%) and an ultralow capacity fade rate of 0.07% per cycle over 300 cycles. Other Li-containing cathodes as LiFePO4 and LiNi0.5Mn0.3Co0.2O2 can also operate effectively at 5 C and 2 C rate, respectively. Such an ingenious design may provide new insights into other solid metal batteries through interfacial engineering manipulation at micro and nano level.

Process for removing copper in a recoverable form from solid scrap metal

DOEpatents

Hartman, Alan D.; Oden, Laurance L.; White, Jack C.

1995-01-01

A process for removing copper in a recoverable form from a copper/solid ferrous scrap metal mix is disclosed. The process begins by placing a copper/solid ferrous scrap metal mix into a reactor vessel. The atmosphere within the reactor vessel is purged with an inert gas or oxidizing while the reactor vessel is heated in the area of the copper/solid ferrous scrap metal mix to raise the temperature within the reactor vessel to a selected elevated temperature. Air is introduced into the reactor vessel and thereafter hydrogen chloride is introduced into the reactor vessel to obtain a desired air-hydrogen chloride mix. The air-hydrogen chloride mix is operable to form an oxidizing and chloridizing atmosphere which provides a protective oxide coating on the surface of the solid ferrous scrap metal in the mix and simultaneously oxidizes/chloridizes the copper in the mix to convert the copper to a copper monochloride gas for transport away from the solid ferrous scrap metal. After the copper is completely removed from the copper/solid ferrous scrap metal mix, the flows of air and hydrogen chloride are stopped and the copper monochloride gas is collected for conversion to a recoverable copper species.

Hydrogen production by high-temperature water splitting using electron-conducting membranes

DOEpatents

Lee, Tae H.; Wang, Shuangyan; Dorris, Stephen E.; Balachandran, Uthamalingam

2004-04-27

A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at disassociation temperatures the hydrogen from the disassociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the disassociation of steam producing hydrogen and oxygen.

Bridging the gap between homogeneous and heterogeneous catalysis: ortho/para H(2) conversion, hydrogen isotope scrambling, and hydrogenation of olefins by Ir(CO)Cl(PPh(3))(2).

PubMed

Matthes, Jochen; Pery, Tal; Gründemann, Stephan; Buntkowsky, Gerd; Sabo-Etienne, Sylviane; Chaudret, Bruno; Limbach, Hans-Heinrich

2004-07-14

Some transition metal complexes are known to catalyze ortho/para hydrogen conversion, hydrogen isotope scrambling, and hydrogenation reactions in liquid solution. Using the example of Vaska's complex, we present here evidence by NMR that the solvent is not necessary for these reactions to occur. Thus, solid frozen solutions or polycrystalline powdered samples of homogeneous catalysts may become heterogeneous catalysts. Comparative liquid- and solid-state studies provide novel insight into the reaction mechanisms.

Mesoporous Phosphate Heterostructures: Synthesis and Application on Adsorption and Catalysis

NASA Astrophysics Data System (ADS)

Moreno-Tost, Ramón; Jiménez-Jiménez, José; Infantes-Molina, Antonia; Cavalcante, Celio L.; Azevedo, Diana C. S.; Soriano, María Dolores; López Nieto, José Manuel; Jiménez-López, Antonio; Rodríguez-Castellón, Enrique

Porous phosphate heterostructures (PPHs) are solids formed by a layered metal(IV) phosphate expanded with silica galleries obtained by combining the two main strategies for obtaining mesoporous materials [pillared layered structures (PLS') and MCM-41]. The different synthetic pathways for obtaining mesoporous phosphate structures with silica galleries with Zr- or Ti-doped silica, the study of their structural, textural and acid properties, its functionalisation with different organic substances such as propionitrile, 3-aminopropyl triethoxysilane, (3-mercaptopropyl)trimethoxysilane, vinyltrimethoxysilane, phenyltriethoxysilane and 3-(triethoxysilyl)propionitrile are discussed. The preparation of metal-supported catalysts and their application in gas separation, adsorption and catalysis are reviewed. Specifically, the use of Cu- and Fe-exchanged PPH for the adsorption of benzothiophene and the separation of propane/propene is the main application as adsorbent. The hydrotreating of aromatic hydrocarbons using ruthenium-impregnated catalysts via hydrogenation and hydrogenolysis/hydrocracking for the production of clean diesel fuels, the selective catalytic reduction of NO from stationary and mobile sources by using Cu-PPH with 1, 3 and 7 wt% of Cu and the selective oxidation of hydrogen sulphide to sulphur with vanadium-containing PPH are the three catalytic reactions of environmental interest studied.

Hydrogen generation via anaerobic fermentation of paper mill wastes.

PubMed

Valdez-Vazquez, Idania; Sparling, Richard; Risbey, Derek; Rinderknecht-Seijas, Noemi; Poggi-Varaldo, Héctor M

2005-11-01

The objective of this work was to determine the hydrogen production from paper mill wastes using microbial consortia of solid substrate anaerobic digesters. Inocula from mesophilic, continuous solid substrate anaerobic digestion (SSAD) reactors were transferred to small lab scale, batch reactors. Milled paper (used as a surrogate paper waste) was added as substrate and acetylene or 2-bromoethanesulfonate (BES) was spiked for methanogenesis inhibition. In the first phase of experiments it was found that acetylene at 1% v/v in the headspace was as effective as BES in inhibiting methanogenic activity. Hydrogen gas accumulated in the headspace of the bottles, reaching a plateau. Similar final hydrogen concentrations were obtained for reactors spiked with acetylene and BES. In the second phase of tests the headspace of the batch reactors was flushed with nitrogen gas after the first plateau of hydrogen was reached, and subsequently incubated, with no further addition of inhibitor nor substrate. It was found that hydrogen production resumed and reached a second plateau, although somewhat lower than the first one. This procedure was repeated a third time and an additional amount of hydrogen was obtained. The plateaux and initial rates of hydrogen accumulation decreased in each subsequent incubation cycle. The total cumulative hydrogen harvested in the three cycles was much higher (approx. double) than in the first cycle alone. We coined this procedure as IV-SSAH (intermittently vented solid substrate anaerobic hydrogen generation). Our results point out to a feasible strategy for obtaining higher hydrogen yields from the fermentation of industrial solid wastes, and a possible combination of waste treatment processes consisting of a first stage IV-SSAH followed by a second SSAD stage. Useful products of this approach would be hydrogen, organic acids or methane, and anaerobic digestates that could be used as soil amenders after post-treatment.

Double-disk solid-phase extraction--Simultaneous cleanup and trace enrichment of herbicides and metabolites from environmental samples

USGS Publications Warehouse

Ferrar, Imma; Barceló, Damià; Thurman, E.M.

1999-01-01

Phenylurea and triazine herbicides, including some metabolites, were isolated from water and soil extracts by solid-phase extraction using a layered system of two extraction disks, a method called double-disk solid-phase extraction. The first disk consisted of strong anion exchange (SAX) of 10-μm styrene divinylbenzene (SDB) particles embedded in Teflon, and the second disk was a C18 disk of 10-μm particles also embedded in Teflon. A volume of 500 mL of water or aqueous soil extract is passed through the layered system with the SAX disk first. The purpose of the SAX disk is to remove the humic and fulvic acids from the water or aqueous soil extract by ion exchange through their carboxyl groups. Even during methanol elution of herbicides, the humic substances remain bound to the SAX disk with >85% retention. Elution with methanol results in more than 90% recovery of the herbicides from the layered extraction disks. Removal of the humic and fulvic acids results in greater sensitivity for diode array detection quantitation (0.05 μg/L for herbicides) by substantially reducing the absorbance of the humic peak on the LC chromatogram. The herbicides adsorb to the SAX disk either through hydrogen bonding to the anion-exchange sites or by hydrophobic interaction with the SDB surface of the anion-exchange disk. The method was tested for the analysis of natural water samples from the Mississippi Embayment, a cotton-growing area of the southeastern United States.

In situ Van der Pauw measurements of the Ni/YSZ anode during exposure to syngas with phosphine contaminant

NASA Astrophysics Data System (ADS)

Demircan, Oktay; Xu, Chunchuan; Zondlo, John; Finklea, Harry O.

Solid oxide fuel cells (SOFCs) represent an option to provide a bridging technology for energy conversion (coal syngas) as well as a long-term technology (hydrogen from biomass). Whether the fuel is coal syngas or hydrogen from biomass, the effect of impurities on the performance of the anode is a vital question. The anode resistivity during SOFC operation with phosphine-contaminated syngas was studied using the in situ Van der Pauw method. Commercial anode-supported solid oxide fuel cells (Ni/YSZ composite anodes, YSZ electrolytes) were exposed to a synthetic coal syngas mixture (H 2, H 2O, CO, and CO 2) at a constant current and their performance evaluated periodically with electrochemical methods (cyclic voltammetry, impedance spectroscopy, and polarization curves). In one test, after 170 h of phosphine exposure, a significant degradation of cell performance (loss of cell voltage, increase of series resistance and increase of polarization resistance) was evident. The rate of voltage loss was 1.4 mV h -1. The resistivity measurements on Ni/YSZ anode by the in situ Van der Pauw method showed that there were no significant changes in anode resistivity both under clean syngas and syngas with 10 ppm PH 3. XRD analysis suggested that Ni 5P 2 and P 2O 5 are two compounds accumulated on the anode. XPS studies provided support for the presence of two phosphorus phases with different oxidation states on the external anode surface. Phosphorus, in a positive oxidation state, was observed in the anode active layer. Based on these observations, the effect of 10 ppm phosphine impurity (or its reaction products with coal syngas) is assigned to the loss of performance of the Ni/YSZ active layer next to the electrolyte, and not to any changes in the thick Ni/YSZ support layer.

Development of a microwave-type densimeter for slush hydrogen

NASA Astrophysics Data System (ADS)

Ohira, K.; Nakamichi, K.; Kihara, Y.

2003-10-01

Slush hydrogen is a two-phase solid-liquid cryogenic fluid consisting of solid hydrogen particles in liquid hydrogen, various applications for which are anticipated, including fuel for reusable space shuttles. The authors of the current study have measured the density of slush hydrogen by using the phase shift that takes place when microwaves are propagated through slush hydrogen, i.e., using the change in the specific dielectric constant. This new technique, unlike the conventional method using a waveguide and horn antenna, features a coaxial cable and patch antenna that can be used at cryogenic temperatures, leading to the development of a slush hydrogen densimeter with a high accuracy of within ±0.5%.

Atomic hydrogen storage method and apparatus

NASA Technical Reports Server (NTRS)

Woollam, J. A. (Inventor)

1978-01-01

Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compound is maintained at liquid helium temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

Atomic hydrogen storage method and apparatus

NASA Technical Reports Server (NTRS)

Woollam, J. A. (Inventor)

1980-01-01

Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compounds maintained at liquid helium temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

Atomic hydrogen storage. [cryotrapping and magnetic field strength

NASA Technical Reports Server (NTRS)

Woollam, J. A. (Inventor)

1980-01-01

Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compound is maintained at liquid temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

A two-dimensional layered Cd(II) coordination polymer with a three-dimensional supramolecular architecture incorporating mixed multidentate N- and O-donor ligands.

PubMed

Huang, Qiu-Ying; Su, Ming-Yang; Meng, Xiang-Ru

2015-06-01

The combination of N-heterocyclic and multicarboxylate ligands is a good choice for the construction of metal-organic frameworks. In the title coordination polymer, poly[bis{μ2-1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole-κ(2)N(3):N(4)}(μ4-butanedioato-κ(4)O(1):O(1'):O(4):O(4'))(μ2-butanedioato-κ(2)O(1):O(4))dicadmium], [Cd(C4H4O4)(C9H8N6)]n, each Cd(II) ion exhibits an irregular octahedral CdO4N2 coordination geometry and is coordinated by four O atoms from three carboxylate groups of three succinate (butanedioate) ligands and two N atoms from two 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) ligands. Cd(II) ions are connected by two kinds of crystallographically independent succinate ligands to generate a two-dimensional layered structure with bimt ligands located on each side of the layer. Adjacent layers are further connected by hydrogen bonding, leading to a three-dimensional supramolecular architecture in the solid state. Thermogravimetric analysis of the title polymer shows that it is stable up to 529 K and then loses weight from 529 to 918 K, corresponding to the decomposition of the bimt ligands and succinate groups. The polymer exhibits a strong fluorescence emission in the solid state at room temperature.

Optical hydrogen sensors based on metal-hydrides

NASA Astrophysics Data System (ADS)

Slaman, M.; Westerwaal, R.; Schreuders, H.; Dam, B.

2012-06-01

For many hydrogen related applications it is preferred to use optical hydrogen sensors above electrical systems. Optical sensors reduce the risk of ignition by spark formation and are less sensitive to electrical interference. Currently palladium and palladium alloys are used for most hydrogen sensors since they are well known for their hydrogen dissociation and absorption properties at relatively low temperatures. The disadvantages of palladium in sensors are the low optical response upon hydrogen loading, the cross sensitivity for oxygen and carbon, the limited detection range and the formation of micro-cracks after some hydrogen absorption/desorption cycles. In contrast to Pd, we find that the use of magnesium or rear earth bases metal-hydrides in optical hydrogen sensors allow tuning of the detection levels over a broad pressure range, while maintaining a high optical response. We demonstrate a stable detection layer for detecting hydrogen below 10% of the lower explosion limit in an oxygen rich environment. This detection layer is deposited at the bare end of a glass fiber as a micro-mirror and is covered with a thin layer of palladium. The palladium layer promotes the hydrogen uptake at room temperature and acts as a hydrogen selective membrane. To protect the sensor for a long time in air a final layer of a hydrophobic fluorine based coating is applied. Such a sensor can be used for example as safety detector in automotive applications. We find that this type of fiber optic hydrogen sensor is also suitable for hydrogen detection in liquids. As example we demonstrate a sensor for detecting a broad range of concentrations in transformer oil. Such a sensor can signal a warning when sparks inside a high voltage power transformer decompose the transformer oil over a long period.

Development and characterization of direct ethanol fuel cells using alkaline anion-exchange membranes

NASA Astrophysics Data System (ADS)

Lim, Peck Cheng

2009-08-01

Alkaline membrane fuel cell (AMFC) is a relatively new fuel cell technology that is generating considerable interests. It offers the electrocatalytic advantages of conventional alkaline fuel cells, and the manufacturing and cost advantages of solid polymer electrolyte fuel cells. This project was carried out to develop and characterize high performance membrane electrode assemblies (MEAs) for all-solid-state AMFCs. The primary fuel of interests is ethanol, but hydrogen was used in the development stages to facilitate the diagnostic and evaluation of the fuel cell performance. In the preliminary investigation, AMFC was assembled using off-the-shelf electrodes and anion-exchange membrane (AEM). It was found that the performance of AMFC operating on ethanol fuel was limited by a large high-frequency resistance (HFR) value. The advantage of using non-toxic ethanol fuel was also compromised by the need to add hydrazine and potassium hydroxide to the fuel blend. Subsequently, a high performance MEA was developed for an all-solid-state AMFC, in which liquid electrolyte or other additives were not required during the operation of the fuel cell. Ionomer was incorporated in the formulation of catalyst ink, and the catalyst ink was directly coated on the anion-exchange membrane (AEM). An ionomer content of 20 wt.% was found to be the optimum amount required in the catalyst layers. It was demonstrated that the AMFC generated a maximum power density of 365 mW/cm2 and 213 mW/cm 2 with the use of hydrogen/oxygen and hydrogen/pure air, respectively. The performance of the AMFC was also found to be influenced by exposure to carbon dioxide in the air. Hence, the CCMs were pre-treated in potassium hydroxide solution and pure oxygen was used to condition the fuel cell to maximize the power output from the AMFCs. Although satisfactory performance was demonstrated in the AMFC, its stability during cell operation remains a major issue. The poor stability was attributed to degradation of ionomer in the catalyst layers, especially at the catalyst/ionomer interfaces. Ethanol was also used as a fuel in the AMFC with newly developed MEAs. Wetproof gas diffusion layers (GDLs) was found to enhance mass transport in liquid-fed AMFC. With the use of 1M ethanol, the AMFC exhibited a maximum power density of 6.482 mW/cm2 and 3.380 mW/cm2 with pure oxygen and ambient air as oxidant, respectively. These maximum power density values are the highest reported to-date. However, significant work is still necessary in advancing the AMFC technology for direct alcohol fuel cell applications.

Energy and fuels from electrochemical interfaces

NASA Astrophysics Data System (ADS)

Stamenkovic, Vojislav R.; Strmcnik, Dusan; Lopes, Pietro P.; Markovic, Nenad M.

2017-01-01

Advances in electrocatalysis at solid-liquid interfaces are vital for driving the technological innovations that are needed to deliver reliable, affordable and environmentally friendly energy. Here, we highlight the key achievements in the development of new materials for efficient hydrogen and oxygen production in electrolysers and, in reverse, their use in fuel cells. A key issue addressed here is the degree to which the fundamental understanding of the synergy between covalent and non-covalent interactions can form the basis for any predictive ability in tailor-making real-world catalysts. Common descriptors such as the substrate-hydroxide binding energy and the interactions in the double layer between hydroxide-oxides and H---OH are found to control individual parts of the hydrogen and oxygen electrochemistry that govern the efficiency of water-based energy conversion and storage systems. Links between aqueous- and organic-based environments are also established, encouraging the 'fuel cell' and 'battery' communities to move forward together.

Space Electrochemical Research and Technology Conference, 2nd, Cleveland, OH, Apr. 11-13, 1989, Proceedings

NASA Technical Reports Server (NTRS)

O'Donnell, Patricia M. (Editor)

1990-01-01

Attention is given to topics of advanced concepts, hydrogen-oxygen fuel cells and electrolyzers, nickel electrodes, and advanced rechargeable batteries. Papers are presented on human exploration mission studies, advanced rechargeable sodium batteries with novel cathodes, advanced double-layer capacitors, recent advances in solid-polymer electrolyte fuel cell technology with low platinum loading electrodes, electrocatalysts for oxygen electrodes in fuel cells and water electrolyzers for space applications, and the corrosion testing of candidates for the alkaline fuel cell cathode. Other papers are on a structural comparison of nickel electodes and precursor phases, the application of electrochemical impedance spectroscopy for characterizing the degradation of Ni(OH)2/NiOOH electrodes, advances in lightweight nickel electrode technology, multimission nickel-hydrogen battery cell for the 1990s, a sodium-sulfur battery flight experiment definition study, and advances in ambient-temperature secondary lithium cells.

MIS-based sensors with hydrogen selectivity

DOEpatents

Li,; Dongmei, [Boulder, CO; Medlin, J William [Boulder, CO; McDaniel, Anthony H [Livermore, CA; Bastasz, Robert J [Livermore, CA

2008-03-11

The invention provides hydrogen selective metal-insulator-semiconductor sensors which include a layer of hydrogen selective material. The hydrogen selective material can be polyimide layer having a thickness between 200 and 800 nm. Suitable polyimide materials include reaction products of benzophenone tetracarboxylic dianhydride 4,4-oxydianiline m-phenylene diamine and other structurally similar materials.

Improving the photoresponse spectra of BaSi2 layers by capping with hydrogenated amorphous Si layers prepared by radio-frequency hydrogen plasma

NASA Astrophysics Data System (ADS)

Xu, Zhihao; Gotoh, Kazuhiro; Deng, Tianguo; Sato, Takuma; Takabe, Ryota; Toko, Kaoru; Usami, Noritaka; Suemasu, Takashi

2018-05-01

We studied the surface passivation effect of hydrogenated amorphous silicon (a-Si:H) layers on BaSi2 films. a-Si:H was formed by an electron-beam evaporation of Si, and a supply of atomic hydrogen using radio-frequency plasma. Surface passivation effect was first investigated on a conventional n-Si(111) substrate by capping with 20 nm-thick a-Si:H layers, and next on a 0.5 μm-thick BaSi2 film on Si(111) by molecular beam epitaxy. The internal quantum efficiency distinctly increased by 4 times in a wide wavelength range for sample capped in situ with a 3 nm-thick a-Si:H layer compared to those capped with a pure a-Si layer.

Adsorption of iodine on hydrogen-reduced silver-exchanged mordenite: Experiments and modeling

DOE PAGES

Nan, Yue; Tavlarides, Lawrence L.; DePaoli, David W.

2016-08-03

The adsorption process of iodine, a major volatile radionuclide in the off-gas streams of spent nuclear fuel reprocessing, on hydrogen-reduced silver-exchanged mordenite (Ag 0Z) was studied at the micro-scale. The gas-solid mass transfer and reaction involved in the adsorption process were investigated and evaluated with appropriate models. Optimal conditions for reducing the silver-exchanged mordenite (AgZ) in a hydrogen stream were determined. Kinetic and equilibrium data of iodine adsorption on Ag 0Z were obtained by performing single-layer adsorption experiments with experimental systems of high precision at 373–473 K over various iodine concentrations. Results indicate approximately 91% to 97% of the iodinemore » adsorption was through the silver-iodine reaction. The effect of temperature on the iodine loading capacity of Ag 0Z was discussed. In conclusion, the Shrinking Core model describes the data well, and the primary rate controlling mechanisms were macro-pore diffusion and silver-iodine reaction. © 2016 American Institute of Chemical Engineers AIChE J, 2016« less

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis.

PubMed

Wilde, Markus; Ohno, Satoshi; Ogura, Shohei; Fukutani, Katsuyuki; Matsuzaki, Hiroyuki

2016-03-29

Nuclear reaction analysis (NRA) via the resonant (1)H((15)N,αγ)(12)C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a (15)N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the (1)H isotope in depths up to about 2 μm from the target surface. Surface H coverages are measured with a sensitivity in the order of ~10(13) cm(-2) (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~10(18) cm(-3) (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal (15)N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, (1)H((15)N,αγ)(12)C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of (15)N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

PubMed Central

Wilde, Markus; Ohno, Satoshi; Ogura, Shohei; Fukutani, Katsuyuki; Matsuzaki, Hiroyuki

2016-01-01

Nuclear reaction analysis (NRA) via the resonant 1H(15N,αγ)12C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a 15N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the 1H isotope in depths up to about 2 μm from the target surface. Surface H coverages are measured with a sensitivity in the order of ~1013 cm-2 (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~1018 cm-3 (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal 15N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, 1H(15N,αγ)12C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of 15N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100). PMID:27077920

Solid Hydrogen Experiments for Atomic Propellants: Particle Formation, Imaging, Observations, and Analyses

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan

2005-01-01

This report presents particle formation observations and detailed analyses of the images from experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Hydrogen was frozen into particles in liquid helium, and observed with a video camera. The solid hydrogen particle sizes and the total mass of hydrogen particles were estimated. These newly analyzed data are from the test series held on February 28, 2001. Particle sizes from previous testing in 1999 and the testing in 2001 were similar. Though the 2001 testing created similar particles sizes, many new particle formation phenomena were observed: microparticles and delayed particle formation. These experiment image analyses are some of the first steps toward visually characterizing these particles, and they allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

Partial oxidation of methane (POM) assisted solid oxide co-electrolysis

DOEpatents

Chen, Fanglin; Wang, Yao

2017-02-21

Methods for simultaneous syngas generation by opposite sides of a solid oxide co-electrolysis cell are provided. The method can comprise exposing a cathode side of the solid oxide co-electrolysis cell to a cathode-side feed stream; supplying electricity to the solid oxide co-electrolysis cell such that the cathode side produces a product stream comprising hydrogen gas and carbon monoxide gas while supplying oxygen ions to an anode side of the solid oxide co-electrolysis cell; and exposing the anode side of the solid oxide co-electrolysis cell to an anode-side feed stream. The cathode-side feed stream comprises water and carbon dioxide, and the anode-side feed stream comprises methane gas such that the methane gas reacts with the oxygen ions to produce hydrogen and carbon monoxide. The cathode-side feed stream can further comprise nitrogen, hydrogen, or a mixture thereof.

Thin film hydrogen sensor

DOEpatents

Lauf, Robert J.; Hoffheins, Barbara S.; Fleming, Pamela H.

1994-01-01

A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

Thin film hydrogen sensor

DOEpatents

Lauf, R.J.; Hoffheins, B.S.; Fleming, P.H.

1994-11-22

A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed. 6 figs.

Plasmonic hydrogen sensor based on integrated microring resonator

NASA Astrophysics Data System (ADS)

Yi, Ya Sha; Wu, Da Chuan

2017-12-01

We have proposed and demonstrated numerically an ultrasmall and highly sensitive plasmonic hydrogen sensor based on an integrated microring resonator, with a footprint size as small as 4×4 μm2. With a palladium (Pd) or platinum (Pt) hydrogen-sensitive layer coated on the inner surface of the microring resonator and the excitation of surface plasmon modes at the interface from the microring resonator waveguide, the device is highly sensitive to low hydrogen concentration variation, and the sensitivity is at least one order of magnitude larger than that of the optical fiber-based hydrogen sensor. We have also investigated the tradeoff between the portion coverage of the Pd/Pt layer and the sensitivity, as well as the width of the hydrogen-sensitive layer. This ultrasmall plasmonic hydrogen sensor holds promise for the realization of a highly compact sensor with integration capability for applications in hydrogen fuel economy.

Detector and energy analyzer for energetic-hydrogen in beams and plasmas

DOEpatents

Bastasz, Robert J.; Hughes, Robert C.; Wampler, William R.

1988-01-01

A detector for detecting energetic hydrogen ions and atoms ranging in energy from about 1 eV up to 1 keV in an evacuated environment includes a Schottky diode with a palladium or palladium-alloy gate metal applied to a silicondioxide layer on an n-silicon substrate. An array of the energetic-hydrogen detectors having a range of energy sensitivities form a plasma energy analyzer having a rapid response time and a sensitivity for measuring fluxes of energetic hydrogen. The detector is sensitive to hydrogen and its isotopes but is insensitive to non-hydrogenic particles. The array of energetic-hydrogen detectors can be formed on a single silicon chip, with thin-film layers of gold metal applied in various thicknesses to successive detectors in the array. The gold layers serve as particle energy-filters so that each detector is sensitive to a different range of hydrogen energies.

Detector and energy analyzer for energetic-hydrogen in beams and plasmas

DOEpatents

Bastasz, R.J.; Hughes, R.C.; Wampler, W.R.

1988-11-01

A detector for detecting energetic hydrogen ions and atoms ranging in energy from about 1 eV up to 1 keV in an evacuated environment includes a Schottky diode with a palladium or palladium-alloy gate metal applied to a silicon-dioxide layer on an n-silicon substrate. An array of the energetic-hydrogen detectors having a range of energy sensitivities form a plasma energy analyzer having a rapid response time and a sensitivity for measuring fluxes of energetic hydrogen. The detector is sensitive to hydrogen and its isotopes but is insensitive to non-hydrogenic particles. The array of energetic-hydrogen detectors can be formed on a single silicon chip, with thin-film layers of gold metal applied in various thicknesses to successive detectors in the array. The gold layers serve as particle energy-filters so that each detector is sensitive to a different range of hydrogen energies. 4 figs.

Microwave plasma generation of arsine from hydrogen and solid arsenic

NASA Astrophysics Data System (ADS)

Omstead, Thomas R.; Annapragada, Ananth V.; Jensen, Klavs F.

1990-12-01

The generation of arsine from the reactions of hydrogen and elemental arsenic in a microwave plasma reactor is described. The arsenic is evaporated from a solid source upstream and carried into the microwave plasma region by a mixture of hydrogen and argon. Stable reaction products, arsine and diarsine are observed by molecular beam sampled mass spectroscopy along with partially hydrogenated species (e.g., AsH and AsH2). The effect of composition and flow rate of the argon/hydrogen carrier gas mixture on the amount of arsine generated is investigated. The arsine production reaches a maximum for an argon-to-hydrogen ratio of unity indicating that metastable argon species act as energy transfer intermediates in the overall reaction. The generation of arsine and diarsine from easily handled solid arsenic by this technique makes it attractive as a possible arsenic source for the growth of compound semiconductors by low-pressure metalorganic chemical vapor deposition.

Chloride ions induce order-disorder transition at water-oxide interfaces

NASA Astrophysics Data System (ADS)

Deshmukh, Sanket; Kamath, Ganesh; Ramanathan, Shriram; Sankaranarayanan, Subramanian K. R. S.

2013-12-01

Water can form quasi-two-dimensional ordered layers near a solid interface. The solvation dynamics and ionic transport phenomena through this ordered water structure is of direct relevance to a variety of problems in interface science. Molecular dynamics simulations are used to study the impact of local fluctuation of the chloride ion density in the vicinity of an oxide surface on the structure and dynamics of water layers. We demonstrate that local increase in chloride ions beyond a threshold concentration near the water-MgO (100) interface introduces an order-disorder transition of this two-dimensional layered network into bulklike water, leading to increased diffusional characteristics and reduced hydrogen bonding lifetimes. We find that the extent of this order-disorder transition can be tuned by modifying the defect chemistry and nature of the underlying substrate. The kinetic fluidity resulting from order-disorder transition at high chloride ion concentration has significance for a broad range of phenomena, ranging from freezing point depression of brine to onset of aqueous corrosion.

High sensitivity, solid state neutron detector

DOEpatents

Stradins, Pauls; Branz, Howard M; Wang, Qi; McHugh, Harold R

2015-05-12

An apparatus (200) for detecting slow or thermal neutrons (160). The apparatus (200) includes an alpha particle-detecting layer (240) that is a hydrogenated amorphous silicon p-i-n diode structure. The apparatus includes a bottom metal contact (220) and a top metal contact (250) with the diode structure (240) positioned between the two contacts (220, 250) to facilitate detection of alpha particles (170). The apparatus (200) includes a neutron conversion layer (230) formed of a material containing boron-10 isotopes. The top contact (250) is pixilated with each contact pixel extending to or proximate to an edge of the apparatus to facilitate electrical contacting. The contact pixels have elongated bodies to allow them to extend across the apparatus surface (242) with each pixel having a small surface area to match capacitance based upon a current spike detecting circuit or amplifier connected to each pixel. The neutron conversion layer (860) may be deposited on the contact pixels (830) such as with use of inkjet printing of nanoparticle ink.

High sensitivity, solid state neutron detector

DOEpatents

Stradins, Pauls; Branz, Howard M.; Wang, Qi; McHugh, Harold R.

2013-10-29

An apparatus (200) for detecting slow or thermal neutrons (160) including an alpha particle-detecting layer (240) that is a hydrogenated amorphous silicon p-i-n diode structure. The apparatus includes a bottom metal contact (220) and a top metal contact (250) with the diode structure (240) positioned between the two contacts (220, 250) to facilitate detection of alpha particles (170). The apparatus (200) includes a neutron conversion layer (230) formed of a material containing boron-10 isotopes. The top contact (250) is pixilated with each contact pixel extending to or proximate to an edge of the apparatus to facilitate electrical contacting. The contact pixels have elongated bodies to allow them to extend across the apparatus surface (242) with each pixel having a small surface area to match capacitance based upon a current spike detecting circuit or amplifier connected to each pixel. The neutron conversion layer (860) may be deposited on the contact pixels (830) such as with use of inkjet printing of nanoparticle ink.

Cathodic electrocatalyst layer for electrochemical generation of hydrogen peroxide

NASA Technical Reports Server (NTRS)

Tennakoon, Charles L. K. (Inventor); Singh, Waheguru Pal (Inventor); Rhodes, Christopher P. (Inventor); Anderson, Kelvin C. (Inventor)

2011-01-01

A cathodic gas diffusion electrode for the electrochemical production of aqueous hydrogen peroxide solutions. The cathodic gas diffusion electrode comprises an electrically conductive gas diffusion substrate and a cathodic electrocatalyst layer supported on the gas diffusion substrate. A novel cathodic electrocatalyst layer comprises a cathodic electrocatalyst, a substantially water-insoluble quaternary ammonium compound, a fluorocarbon polymer hydrophobic agent and binder, and a perfluoronated sulphonic acid polymer. An electrochemical cell using the novel cathodic electrocatalyst layer has been shown to produce an aqueous solution having between 8 and 14 weight percent hydrogen peroxide. Furthermore, such electrochemical cells have shown stable production of hydrogen peroxide solutions over 1000 hours of operation including numerous system shutdowns.

Thin-thick hydrogen target for nuclear physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gheller, J.-M.; Juster, F.-P.; Authelet, G.

In spectroscopic studies of unstable nuclei, hydrogen targets are of key importance. The CHyMENE Project aims to provide to the nuclear physics community a thin and pure solid windowless hydrogen or deuterium target. CHyMENE project must respond to this request for the production of solid Hydrogen. The solid hydrogen target is produced in a continuous flow (1 cm/s) by an extrusion technique (developed with the PELIN laboratory) in a vacuum chamber. The shape of the target is determined by the design of the nozzle at the extrusion process. For the purpose, the choice is a rectangular shape with a widthmore » of 10 mm and a thickness in the range of 30-50 microns necessary for the physics objectives. The cryostat is equipped with a GM Cryocooler with sufficient power for the solidification of the hydrogen in the lower portion of the extruder. In the higher part of the cryostat, the hydrogen gas is first liquefied and partially solidified. It is then compressed at 100 bars in the cooled extruder before expulsion of the film through the nozzle at the center of the reaction vacuum chamber. After the previous step, the solid hydrogen ribbon falls by gravity into a dedicated chamber where it sublimes and the gas is pumped and evacuated in a exhaust line. This paper deals with the design of the cryostat with its equipment, with the sizing of the thermal bridge (Aluminum and copper), with the results regarding the contact resistance as well as with the vacuum computations of the reaction and recovery hydrogen gas chambers.« less

Solid Aluminum Borohydrides for Prospective Hydrogen Storage.

PubMed

Dovgaliuk, Iurii; Safin, Damir A; Tumanov, Nikolay A; Morelle, Fabrice; Moulai, Adel; Černý, Radovan; Łodziana, Zbigniew; Devillers, Michel; Filinchuk, Yaroslav

2017-12-08

Metal borohydrides are intensively researched as high-capacity hydrogen storage materials. Aluminum is a cheap, light, and abundant element and Al 3+ can serve as a template for reversible dehydrogenation. However, Al(BH 4 ) 3 , containing 16.9 wt % of hydrogen, has a low boiling point, is explosive on air and has poor storage stability. A new family of mixed-cation borohydrides M[Al(BH 4 ) 4 ], which are all solid under ambient conditions, show diverse thermal decomposition behaviors: Al(BH 4 ) 3 is released for M=Li + or Na + , whereas heavier derivatives evolve hydrogen and diborane. NH 4 [Al(BH 4 ) 4 ], containing both protic and hydridic hydrogen, has the lowest decomposition temperature of 35 °C and yields Al(BH 4 ) 3 ⋅NHBH and hydrogen. The decomposition temperatures, correlated with the cations' ionic potential, show that M[Al(BH 4 ) 4 ] species are in the most practical stability window. This family of solids, with convenient and versatile properties, puts aluminum borohydride chemistry in the mainstream of hydrogen storage research, for example, for the development of reactive hydride composites with increased hydrogen content. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The phase diagram of hydrogen in ultra thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jisrawi, N.M.; Ruckman, M.W.; Reisfeld, G.

This paper, we discuss changes in the phase diagram of hydrogen in both bilayer (i.e. 200-2000 {Angstrom} Nb/100 {Angstrom} Pd on glass) and multilayer configurations. Comparison of x-ray diffraction, electrical resistivity and volumetric measurements of the films before and after hydrogen charging indicate that the phase equilibria between a correlated (high concentration) and a dilute phase of hydrogen in Nb is not sensitive to the number of layers in the films. On the other hand, the experimental methods show different behavior for 200 {Angstrom} thick Nb films and thicker (>400 {Angstrom}) Nb layers. The diffraction results also show that, whilemore » charging with hydrogen, the Nb layers mainly expand along the surface normal of the films, while the Pd layers expand in all directions equally, and transform to the bulk {alpha} phase.« less

Preparation of a self-humidifying membrane electrode assembly for fuel cell and its performance analysis

NASA Astrophysics Data System (ADS)

Wang, Cheng; Mao, Zongqiang; Xu, Jingming; Xie, Xiaofeng; Yang, Lizhai

2003-10-01

A novel nano-porous material SiO2-gel was prepared. After being purified by H2O2, then protonized by H2SO4 and desiccated in vacuum, the SiO2-gel, mixed with Nafion solution, was coated between an electrode and a solid electrolyte, which made a new type of self-humidifying membrane electrode assembly. The SiO2 powder was characterized by FTIR, BET and XRD. The surface of the electrodes was characterized by SEM and EDS. The performances of the self-humidifying membrane electrodes were analyzed by polarization discharge and AC impedance under the operation modes of external humidification and self-humidification respectively. Experimental-results indicated that the SiO2 powder held super-hydrophilicity, and the layer of SiO2 and Nafion polymer between electrode and solid electrolyte expanded three-dimension electrochemistry reac-tion area, maintained stability of catalyst layer and enhanced back-diffusion of water from cathode to anode, so the PEM Fuel cell can generate electricity at self-humidification mode. The power density of single PEM fuel cell reached 1.5 W/cm2 under 0.2 Mpa, 70°C and dry hydrogen and oxygen.

Stability of surface and subsurface hydrogen on and in Au/Ni near-surface alloys

DOE PAGES

Celik, Fuat E.; Mavrikakis, Manos

2015-01-12

Periodic, self-consistent DFT-GGA (PW91) calculations were used to study the interaction of hydrogen atoms with the (111) surfaces of substitutional near-surface alloys (NSAs) of Au and Ni with different surface layer compositions and different arrangements of Au atoms in the surface layer. The effect of hydrogen adsorption on the surface and in the first and second subsurface layers of the NSAs was studied. Increasing the Au content in the surface layer weakens hydrogen binding on the surface, but strengthens subsurface binding, suggesting that the distribution of surface and subsurface hydrogen will be different than that on pure Ni(111). While themore » metal composition of the surface layer has an effect on the binding energy of hydrogen on NSA surfaces, the local composition of the binding site has a stronger effect. For example, fcc hollow sites consisting of three Ni atoms bind H nearly as strongly as on Ni(111), and fcc sites consisting of three Au atoms bind H nearly as weakly as on Au(111). Sites with one or two Au atoms show intermediate binding energies. The preference of hydrogen for three-fold Ni hollow sites alters the relative stabilities of different surface metal atom arrangements, and may provide a driving force for adsorbate-induced surface rearrangement.« less

Stability of Surface and Subsurface Hydrogen on and in Au/Ni Near-Surface Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Celik, Fuat E.; Mavrikakis, Manos

2015-10-01

Periodic, self-consistent DFT-GGA (PW91) calculations were used to study the interaction of hydrogen atoms with the (111) surfaces of substitutional near-surface alloys (NSAs) of Au and Ni with different surface layer compositions and different arrangements of Au atoms in the surface layer. The effect of hydrogen adsorption on the surface and in the first and second subsurface layers of the NSAs was studied. Increasing the Au content in the surface layer weakens hydrogen binding on the surface, but strengthens subsurface binding, suggesting that the distribution of surface and subsurface hydrogen will be different than that on pure Ni(111). While themore » metal composition of the surface layer has an effect on the binding energy of hydrogen on NSA surfaces, the local composition of the binding site has a stronger effect. For example, fcc hollow sites consisting of three Ni atoms bind H nearly as strongly as on Ni(111), and fcc sites consisting of three Au atoms bind H nearly as weakly as on Au(111). Sites with one or two Au atoms show intermediate binding energies. The preference of hydrogen for three-fold Ni hollow sites alters the relative stabilities of different surface metal atom arrangements, and may provide a driving force for adsorbate-induced surface rearrangement.« less

Stability of surface and subsurface hydrogen on and in Au/Ni near-surface alloys

NASA Astrophysics Data System (ADS)

Celik, Fuat E.; Mavrikakis, Manos

2015-10-01

Periodic, self-consistent DFT-GGA (PW91) calculations were used to study the interaction of hydrogen atoms with the (111) surfaces of substitutional near-surface alloys (NSAs) of Au and Ni with different surface layer compositions and different arrangements of Au atoms in the surface layer. The effect of hydrogen adsorption on the surface and in the first and second subsurface layers of the NSAs was studied. Increasing the Au content in the surface layer weakens hydrogen binding on the surface, but strengthens subsurface binding, suggesting that the distribution of surface and subsurface hydrogen will be different than that on pure Ni(111). While the metal composition of the surface layer has an effect on the binding energy of hydrogen on NSA surfaces, the local composition of the binding site has a stronger effect. For example, fcc hollow sites consisting of three Ni atoms bind H nearly as strongly as on Ni(111), and fcc sites consisting of three Au atoms bind H nearly as weakly as on Au(111). Sites with one or two Au atoms show intermediate binding energies. The preference of hydrogen for three-fold Ni hollow sites alters the relative stabilities of different surface metal atom arrangements, and may provide a driving force for adsorbate-induced surface rearrangement.

Multiphysics Computational Analysis of a Solid-Core Nuclear Thermal Engine Thrust Chamber

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Canabal, Francisco; Cheng, Gary; Chen, Yen-Sen

2007-01-01

The objective of this effort is to develop an efficient and accurate computational heat transfer methodology to predict thermal, fluid, and hydrogen environments for a hypothetical solid-core, nuclear thermal engine - the Small Engine. In addition, the effects of power profile and hydrogen conversion on heat transfer efficiency and thrust performance were also investigated. The computational methodology is based on an unstructured-grid, pressure-based, all speeds, chemically reacting, computational fluid dynamics platform, while formulations of conjugate heat transfer were implemented to describe the heat transfer from solid to hydrogen inside the solid-core reactor. The computational domain covers the entire thrust chamber so that the afore-mentioned heat transfer effects impact the thrust performance directly. The result shows that the computed core-exit gas temperature, specific impulse, and core pressure drop agree well with those of design data for the Small Engine. Finite-rate chemistry is very important in predicting the proper energy balance as naturally occurring hydrogen decomposition is endothermic. Locally strong hydrogen conversion associated with centralized power profile gives poor heat transfer efficiency and lower thrust performance. On the other hand, uniform hydrogen conversion associated with a more uniform radial power profile achieves higher heat transfer efficiency, and higher thrust performance.

Effect of hydrogen on the device performance and stability characteristics of amorphous InGaZnO thin-film transistors with a SiO2/SiNx/SiO2 buffer

NASA Astrophysics Data System (ADS)

Han, Ki-Lim; Ok, Kyung-Chul; Cho, Hyeon-Su; Oh, Saeroonter; Park, Jin-Seong

2017-08-01

We investigate the influence of the multi-layered buffer consisting of SiO2/SiNx/SiO2 on amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs). The multi-layered buffer inhibits permeation of water from flexible plastic substrates and prevents degradation of overlying organic layers. The a-IGZO TFTs with a multi-layered buffer suffer less positive bias temperature stress instability compared to the device with a single SiO2 buffer layer after annealing at 250 °C. Hydrogen from the SiNx layer diffuses into the active layer and reduces electron trapping at loosely bound oxygen defects near the SiO2/a-IGZO interface. Quantitative analysis shows that a hydrogen density of 1.85 × 1021 cm-3 is beneficial to reliability. However, the multi-layered buffer device annealed at 350 °C resulted in conductive characteristics due to the excess carrier concentration from the higher hydrogen density of 2.12 × 1021 cm-3.

Hydrogen bonding pattern in N-benzoyl(- DL-)- L-phenylalanines as revealed by solid-state NMR spectroscopy

NASA Astrophysics Data System (ADS)

Potrzebowski, M. J.; Schneider, C.; Tekely, P.

1999-11-01

The nature of the hydrogen bonding pattern has been investigated in N-benzoyl- DL-phenylalanine ( 1) and N-benzoyl- L-phenylalanine ( 2) polymorphes by solid-state NMR spectroscopy. It has been shown that the multiple resonances of carboxyl carbon in 2 are directly connected to different types of hydrogen bonding. The differences in intermolecular distances of carboxyl groups involved in different types of hydrogen bonding have been visualized by the 2D exchange and 1D ODESSA experiments. Potential applications of such a new approach include the exploration of intermolecular distances in hydrogen bonded compounds with singly labeled biomolecules.

Systems and methods for selective hydrogen transport and measurement

DOEpatents

Glatzmaier, Gregory C

2013-10-29

Systems and methods for selectively removing hydrogen gas from a hydrogen-containing fluid volume are disclosed. An exemplary system includes a proton exchange membrane (PEM) selectively permeable to hydrogen by exclusively conducting hydrogen ions. The system also includes metal deposited as layers onto opposite sides or faces of the PEM to form a membrane-electrode assembly (MEA), each layer functioning as an electrode so that the MEA functions as an electrochemical cell in which the ionic conductors are hydrogen ions, and the MEA functioning as a hydrogen selective membrane (HSM) when located at the boundary between a hydrogen-containing fluid volume and a second fluid.

Relationship Between Particle and Plasma Properties and Coating Characteristics of Samaria-Doped Ceria Prepared by Atmospheric Plasma Spraying for Use in Solid Oxide Fuel Cells

NASA Astrophysics Data System (ADS)

Cuglietta, Mark; Kesler, Olivera

2012-06-01

Samaria-doped ceria (SDC) has become a promising material for the fabrication of high-performance, intermediate-temperature solid oxide fuel cells (SOFCs). In this study, the in-flight characteristics, such as particle velocity and surface temperature, of spray-dried SDC agglomerates were measured and correlated to the resulting microstructures of SDC coatings fabricated using atmospheric plasma spraying, a manufacturing technique with the capability of producing full cells in minutes. Plasmas containing argon, nitrogen and hydrogen led to particle surface temperatures higher than those in plasmas containing only argon and nitrogen. A threshold temperature for the successful deposition of SDC on porous stainless steel substrates was calculated to be 2570 °C. Coating porosity was found to be linked to average particle temperature, suggesting that plasma conditions leading to lower particle temperatures may be most suitable for fabricating porous SOFC electrode layers.

Anode protection system for shutdown of solid oxide fuel cell system

DOEpatents

Li, Bob X; Grieves, Malcolm J; Kelly, Sean M

2014-12-30

An Anode Protection Systems for a SOFC system, having a Reductant Supply and safety subsystem, a SOFC anode protection subsystem, and a Post Combustion and slip stream control subsystem. The Reductant Supply and safety subsystem includes means for generating a reducing gas or vapor to prevent re-oxidation of the Ni in the anode layer during the course of shut down of the SOFC stack. The underlying ammonia or hydrogen based material used to generate a reducing gas or vapor to prevent the re-oxidation of the Ni can be in either a solid or liquid stored inside a portable container. The SOFC anode protection subsystem provides an internal pressure of 0.2 to 10 kPa to prevent air from entering into the SOFC system. The Post Combustion and slip stream control subsystem provides a catalyst converter configured to treat any residual reducing gas in the slip stream gas exiting from SOFC stack.

Coal liquefaction process wherein jet fuel, diesel fuel and/or ASTM No. 2 fuel oil is recovered

DOEpatents

Bauman, Richard F.; Ryan, Daniel F.

1982-01-01

An improved process for the liquefaction of coal and similar solid carbonaceous materials wherein a hydrogen donor solvent or diluent derived from the solid carbonaceous material is used to form a slurry of the solid carbonaceous material and wherein the naphthenic components from the solvent or diluent fraction are separated and used as jet fuel components. The extraction increases the relative concentration of hydroaromatic (hydrogen donor) components and as a result reduces the gas yield during liquefaction and decreases hydrogen consumption during said liquefaction. The hydrogenation severity can be controlled to increase the yield of naphthenic components and hence the yield of jet fuel and in a preferred embodiment jet fuel yield is maximized while at the same time maintaining solvent balance.

Composite metal membrane

DOEpatents

Peachey, Nathaniel M.; Dye, Robert C.; Snow, Ronny C.; Birdsell, Stephan A.

1998-01-01

A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

Composite metal membrane

DOEpatents

Peachey, N.M.; Dye, R.C.; Snow, R.C.; Birdsell, S.A.

1998-04-14

A composite metal membrane including a first metal layer of Group IVB met or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof is provided together with a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a nonporous composite metal membrane including a first metal of Group IVB metals or Group VB metals, the first metal layer sandwiched between two layers of an oriented metal of palladium, platinum or alloys thereof, and, separating hydrogen from a second side of the nonporous composite metal membrane.

Method and Pd/V2 O5 device for H2 detection

DOEpatents

Liu, Ping [San Diego, CA; Tracy, C Edwin [Golden, CO; Pitts, J Roland [Lakewood, CO; Smith, II, R. Davis; Lee, Se-Hee [Lakewood, CO

2011-12-27

Methods and Pd/V.sub.2O.sub.5 devices for hydrogen detection are disclosed. An exemplary method of preparing an improved sensor for chemochromic detection of hydrogen gas over a wide response range exhibits stability during repeated coloring/bleaching cycles upon exposure and removal of hydrogen gas. The method may include providing a substrate. The method may also include depositing a V.sub.20.sub.5 layer that functions as a H.sub.2 insertion host in a Pd/V.sub.20.sub.5 hydrogen sensor to be formed on said substrate. The method may also include depositing a Pd layer onto said V.sub.20.sub.5 layer; said Pd layer functioning as an optical modulator.

Study on monatomic fraction improvement with alumina layer on metal electrode in hydrogen plasma ion source.

PubMed

Jung, Bong-Ki; Chung, Kyoung-Jae; Dang, Jeong-Jeung; Hwang, Y S

2012-02-01

A high monatomic beam fraction is an important factor in a hydrogen ion source to increase the application efficiency. The monatomic fraction of hydrogen plasmas with different plasma electrode materials is measured in a helicon plasma ion source, and aluminum shows the highest value compared to that with the other metals such as copper and molybdenum. Formation of an aluminum oxide layer on the aluminum electrode is determined by XPS analysis, and the alumina layer is verified as the high monatomic fraction. Both experiments and numerical simulations conclude that a low surface recombination coefficient of the alumina layer on the plasma electrode is one of the most important parameters for increasing the monatomic fraction in hydrogen plasma ion sources.

Study on monatomic fraction improvement with alumina layer on metal electrode in hydrogen plasma ion sourcea)

NASA Astrophysics Data System (ADS)

Jung, Bong-Ki; Chung, Kyoung-Jae; Dang, Jeong-Jeung; Hwang, Y. S.

2012-02-01

A high monatomic beam fraction is an important factor in a hydrogen ion source to increase the application efficiency. The monatomic fraction of hydrogen plasmas with different plasma electrode materials is measured in a helicon plasma ion source, and aluminum shows the highest value compared to that with the other metals such as copper and molybdenum. Formation of an aluminum oxide layer on the aluminum electrode is determined by XPS analysis, and the alumina layer is verified as the high monatomic fraction. Both experiments and numerical simulations conclude that a low surface recombination coefficient of the alumina layer on the plasma electrode is one of the most important parameters for increasing the monatomic fraction in hydrogen plasma ion sources.

Cooling by Para-to-Ortho-Hydrogen Conversion

NASA Technical Reports Server (NTRS)

Sherman, A.; Nast, T.

1983-01-01

Catalyst speeds conversion, increasing capacity of solid hydrogen cooling system. In radial-flow catalytic converter, para-hydrogen is converted to equilibrium mixture of para-hydrogen and ortho-hydrogen as it passes through porous cylinder of catalyst. Addition of catalyst increases capacity of hydrogen sublimation cooling systems for radiation detectors.

DEGRADATION ISSUES IN SOLID OXIDE CELLS DURING HIGH TEMPERATURE ELECTROLYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. S. Sohal; J. E. O'Brien; C. M. Stoots

2012-02-01

Idaho National Laboratory (INL) is performing high-temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells (SOECs). The project goals are to address the technical and degradation issues associated with the SOECs. This paper provides a summary of various ongoing INL and INL sponsored activities aimed at addressing SOEC degradation. These activities include stack testing, post-test examination, degradation modeling, and a list of issues that need to be addressed in future. Major degradation issues relating to solid oxide fuel cells (SOFC) are relatively better understood than those for SOECs. Some of the degradation mechanisms in SOFCs include contact problemsmore » between adjacent cell components, microstructural deterioration (coarsening) of the porous electrodes, and blocking of the reaction sites within the electrodes. Contact problems include delamination of an electrode from the electrolyte, growth of a poorly (electronically) conducting oxide layer between the metallic interconnect plates and the electrodes, and lack of contact between the interconnect and the electrode. INL's test results on high temperature electrolysis (HTE) using solid oxide cells do not provide a clear evidence whether different events lead to similar or drastically different electrochemical degradation mechanisms. Post-test examination of the solid oxide electrolysis cells showed that the hydrogen electrode and interconnect get partially oxidized and become non-conductive. This is most likely caused by the hydrogen stream composition and flow rate during cool down. The oxygen electrode side of the stacks seemed to be responsible for the observed degradation due to large areas of electrode delamination. Based on the oxygen electrode appearance, the degradation of these stacks was largely controlled by the oxygen electrode delamination rate. University of Utah (Virkar) has developed a SOEC model based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic non-equilibrium. This model is under continued development. It shows that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, within the electrolyte. The chemical potential within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just under the oxygen electrode (anode)/electrolyte interface, leading to electrode delamination. This theory is being further refined and tested by introducing some electronic conduction in the electrolyte.« less

DEGRADATION ISSUES IN SOLID OXIDE CELLS DURING HIGH TEMPERATURE ELECTROLYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. E. O'Brien; C. M. Stoots; V. I. Sharma

2010-06-01

Idaho National Laboratory (INL) is performing high-temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells (SOECs). The project goals are to address the technical and degradation issues associated with the SOECs. This paper provides a summary of various ongoing INL and INL sponsored activities aimed at addressing SOEC degradation. These activities include stack testing, post-test examination, degradation modeling, and a list of issues that need to be addressed in future. Major degradation issues relating to solid oxide fuel cells (SOFC) are relatively better understood than those for SOECs. Some of the degradation mechanisms in SOFCs include contact problemsmore » between adjacent cell components, microstructural deterioration (coarsening) of the porous electrodes, and blocking of the reaction sites within the electrodes. Contact problems include delamination of an electrode from the electrolyte, growth of a poorly (electronically) conducting oxide layer between the metallic interconnect plates and the electrodes, and lack of contact between the interconnect and the electrode. INL’s test results on high temperature electrolysis (HTE) using solid oxide cells do not provide a clear evidence whether different events lead to similar or drastically different electrochemical degradation mechanisms. Post-test examination of the solid oxide electrolysis cells showed that the hydrogen electrode and interconnect get partially oxidized and become non-conductive. This is most likely caused by the hydrogen stream composition and flow rate during cool down. The oxygen electrode side of the stacks seemed to be responsible for the observed degradation due to large areas of electrode delamination. Based on the oxygen electrode appearance, the degradation of these stacks was largely controlled by the oxygen electrode delamination rate. University of Utah (Virkar) has developed a SOEC model based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic non-equilibrium. This model is under continued development. It shows that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, within the electrolyte. The chemical potential within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just under the oxygen electrode (anode)/electrolyte interface, leading to electrode delamination. This theory is being further refined and tested by introducing some electronic conduction in the electrolyte.« less

Electrolysis-induced protonation of VO2 thin film transistor for the metal-insulator phase modulation

NASA Astrophysics Data System (ADS)

Katase, Takayoshi; Endo, Kenji; Ohta, Hiromichi

2016-02-01

Compared to state-of-the-art modulation techniques, protonation is the most ideal to control the electrical and optical properties of transition metal oxides (TMOs) due to its intrinsic non-volatile operation. However, the protonation of TMOs is not typically utilized for solid-state devices because of imperative high-temperature annealing treatment in hydrogen source. Although one solution for room temperature (RT) protonation of TMOs is liquid-phase electrochemistry, it is unsuited for practical purposes due to liquid-leakage problem. Herein we demonstrate solid-state RT-protonation of vanadium dioxide (VO2), which is a well-known thermochromic TMO. We fabricated the three terminal thin-film-transistor structure on an insulating VO2 film using a water-infiltrated nanoporous glass, which serves as a solid electrolyte. For gate voltage application, water electrolysis and protonation/deprotonation of VO2 film surface occurred, leading to reversible metal-insulator phase conversion of ~11-nm-thick VO2 layer. The protonation was clearly accompanied by the structural change from an insulating monoclinic to a metallic tetragonal phase. Present results offer a new route for the development of electro-optically active solid-state devices with TMO materials by engineering RT protonation.

Thermophilic anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW) with food waste (FW): Enhancement of bio-hydrogen production.

PubMed

Angeriz-Campoy, Rubén; Álvarez-Gallego, Carlos J; Romero-García, Luis I

2015-10-01

Bio-hydrogen production from dry thermophilic anaerobic co-digestion (55°C and 20% total solids) of organic fraction of municipal solid waste (OFMSW) and food waste (FW) was studied. OFMSW coming from mechanical-biological treatment plants (MBT plants) presents a low organic matter concentration. However, FW has a high organic matter content but several problems by accumulation of volatile fatty acids (VFAs) and system acidification. Tests were conducted using a mixture ratio of 80:20 (OFSMW:FW), to avoid the aforementioned problems. Different solid retention times (SRTs) - 6.6, 4.4, 2.4 and 1.9 days - were tested. It was noted that addition of food waste enhances the hydrogen production in all the SRTs tested. Best results were obtained at 1.9-day SRT. It was observed an increase from 0.64 to 2.51 L H2/L(reactor) day in hydrogen productivity when SRTs decrease from 6.6 to 1.9 days. However, the hydrogen yield increases slightly from 33.7 to 38 mL H2/gVS(added). Copyright © 2015 Elsevier Ltd. All rights reserved.

Current Development in Treatment and Hydrogen Energy Conversion of Organic Solid Waste

NASA Astrophysics Data System (ADS)

Shin, Hang-Sik

2008-02-01

This manuscript summarized current developments on continuous hydrogen production technologies researched in Korea advanced institute of science and technology (KAIST). Long-term continuous pilot-scale operation of hydrogen producing processes fed with non-sterile food waste exhibited successful results. Experimental findings obtained by the optimization processes of growth environments for hydrogen producing bacteria, the development of high-rate hydrogen producing strategies, and the feasibility tests for real field application could contribute to the progress of fermentative hydrogen production technologies. Three major technologies such as controlling dilution rate depending on the progress of acidogenesis, maintaining solid retention time independently from hydraulic retention time, and decreasing hydrogen partial pressure by carbon dioxide sparging could enhance hydrogen production using anaerobic leaching beds reactors and anaerobic sequencing batch reactors. These findings could contribute to stable, reliable and effective performances of pilot-scale reactors treating organic wastes.

Water structuring and collagen adsorption at hydrophilic and hydrophobic silicon surfaces.

PubMed

Cole, Daniel J; Payne, Mike C; Ciacchi, Lucio Colombi

2009-12-28

The adsorption of a collagen fragment on both a hydrophobic, hydrogen-terminated and a hydrophilic, natively oxidised Si surface is investigated using all-atom molecular dynamics. While favourable direct protein-surface interactions via localised contact points characterise adhesion to the hydrophilic surface, evenly spread surface/molecule contacts and stabilisation of the helical structure occurs upon adsorption on the hydrophobic surface. In the latter case, we find that adhesion is accompanied by a mutual fit between the hydrophilic/hydrophobic pattern within the protein and the layered water structure at the solid/liquid interface, which may provide an additional driving force to the classic hydrophobic effect.

Interaction of water vapor with silicate glass surfaces: Mass-spectrometric investigations

NASA Astrophysics Data System (ADS)

Kudriavtsev, Yu.; Asomoza-Palacio, R.; Manzanilla-Naim, L.

2017-05-01

The secondary ion mass-spectroscopy technique was used to study the results of hydration of borosilicate, aluminosilicate, and soda-lime silicate glasses in 1H2 18O water vapor containing 97% of the isotope 18O. It is shown that hydration of the surface of the soda-lime silicate glass occurs as a result of the ion-exchange reaction with alkali metals. In the case of borosilicate and aluminosilicate glasses, water molecules decompose on the glass surface, with the observed formation of hydrogenated layer in the glass being the result of a solid-state chemical reaction—presumably, with the formation of hydroxides from aluminum and boron oxides.

Infrared laboratory studies of synthetic planetary atmospheres

NASA Technical Reports Server (NTRS)

Williams, D.

1977-01-01

Topics covered include: the broadening of individual lines in the CO fundamental by various gases; total band absorptance as a function of absorber thickness and total effect pressure at various temperatures for bands of CO and N2O; nitric acid vapor content in the region of the ozone layer; optical properties of solid NH3; HSO4 concentration in Venus clouds; Burch's law of multiplicative transmittance for mixing absorbing gases when their lines are broadened by helium and hydrogen; ling strength and self-broadening parameters in the v3 fundamental of CO2 and N2O; optical constants of liquid ammonia, liquid methane, saturated hydrocarbons, ammonium hydride and ammonium salts.

Recovery of lithium and cobalt from spent lithium-ion batteries using organic acids: Process optimization and kinetic aspects.

PubMed

Golmohammadzadeh, Rabeeh; Rashchi, Fereshteh; Vahidi, Ehsan

2017-06-01

An environmentally-friendly route based on hydrometallurgy was investigated for the recovery of cobalt and lithium from spent lithium ion batteries (LIBs) using different organic acids (citric acid, Dl-malic acid, oxalic acid and acetic acid). In this investigation, response surface methodology (RSM) was utilized to optimize leaching parameters including solid to liquid ratio (S/L), temperature, acid concentration, type of organic acid and hydrogen peroxide concentration. Based on the results obtained from optimizing procedure, temperature was recognized as the most influential parameter. In addition, while 81% of cobalt was recovered, the maximum lithium recovery of 92% was achieved at the optimum leaching condition of 60°C, S/L: 30gL -1 , citric acid concentration: 2M, hydrogen peroxide concentration: 1.25Vol.% and leaching time: 2h. Furthermore, results displayed that ultrasonic agitation will enhance the recovery of lithium and cobalt. It was found that the kinetics of cobalt leaching is controlled by surface chemical reaction at temperatures lower than 45°C. However, diffusion through the product layer at temperatures higher than 45°C controls the rate of cobalt leaching. Rate of lithium reaction is controlled by diffusion through the product layer at all the temperatures studied. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogen Bonding: Between Strengthening the Crystal Packing and Improving Solubility of Three Haloperidol Derivatives.

PubMed

Saluja, Hardeep; Mehanna, Ahmed; Panicucci, Riccardo; Atef, Eman

2016-06-01

The purpose of this study is to confirm the impact of polar functional groups on inter and intra-molecular hydrogen bonding in haloperidol (HP) and droperidol (DP) and, hence, their effects on dissolution using a new approach. To confirm our theory, a new molecule: deshydroxy-haloperidol (DHP) was designed and its synthesis was requested from a contract laboratory. The molecule was then studied and compared to DP and HP. Unlike DHP, both the HP and DP molecules have hydrogen donor groups, therefore, DHP was used to confirm the relative effects of the hydrogen donor group on solubility and crystal packing. The solid dispersions of the three structurally related molecules: HP, DP, and DHP were prepared using PVPK30, and characterized using XRPD and IR. A comparative dissolution study was carried out in aqueous medium. The absence of a hydrogen bonding donor group in DHP resulted in an unexpected increase in its aqueous solubility and dissolution rate from solid dispersion, which is attributed to weaker crystal pack. The increased dissolution rate of HP and DP from solid dispersions is attributed to drug-polymer hydrogen bonding that interferes with the drug-drug intermolecular hydrogen bonding and provides thermodynamic stability of the dispersed drug molecules. The drug-drug intermolecular hydrogen bond is the driving force for precipitation and crystal packing.

Effect of dual-dielectric hydrogen-diffusion barrier layers on the performance of low-temperature processed transparent InGaZnO thin-film transistors

NASA Astrophysics Data System (ADS)

Tari, Alireza; Wong, William S.

2018-02-01

Dual-dielectric SiOx/SiNx thin-film layers were used as back-channel and gate-dielectric barrier layers for bottom-gate InGaZnO (IGZO) thin-film transistors (TFTs). The concentration profiles of hydrogen, indium, gallium, and zinc oxide were analyzed using secondary-ion mass spectroscopy characterization. By implementing an effective H-diffusion barrier, the hydrogen concentration and the creation of H-induced oxygen deficiency (H-Vo complex) defects during the processing of passivated flexible IGZO TFTs were minimized. A bilayer back-channel passivation layer, consisting of electron-beam deposited SiOx on plasma-enhanced chemical vapor-deposition (PECVD) SiNx films, effectively protected the TFT active region from plasma damage and minimized changes in the chemical composition of the semiconductor layer. A dual-dielectric PECVD SiOx/PECVD SiNx gate-dielectric, using SiOx as a barrier layer, also effectively prevented out-diffusion of hydrogen atoms from the PECVD SiNx-gate dielectric to the IGZO channel layer during the device fabrication.

Cyclic etching of tin-doped indium oxide using hydrogen-induced modified layer

NASA Astrophysics Data System (ADS)

Hirata, Akiko; Fukasawa, Masanaga; Nagahata, Kazunori; Li, Hu; Karahashi, Kazuhiro; Hamaguchi, Satoshi; Tatsumi, Tetsuya

2018-06-01

The rate of etching of tin-doped indium oxide (ITO) and the effects of a hydrogen-induced modified layer on cyclic, multistep thin-layer etching were investigated. It was found that ITO cyclic etching is possible by precisely controlling the hydrogen-induced modified layer. Highly selective etching of ITO/SiO2 was also investigated, and it was suggested that cyclic etching by selective surface adsorption of Si can precisely control the etch rates of ITO and SiO2, resulting in an almost infinite selectivity for ITO over SiO2 and in improved profile controllability.

Prediction of a new graphenelike Si2BN solid

NASA Astrophysics Data System (ADS)

Andriotis, Antonis N.; Richter, Ernst; Menon, Madhu

2016-02-01

While the possibility to create a single-atom-thick two-dimensional layer from any material remains, only a few such structures have been obtained other than graphene and a monolayer of boron nitride. Here, based upon ab initio theoretical simulations, we propose a new stable graphenelike single-atomic-layer Si2BN structure that has all of its atoms with s p2 bonding with no out-of-plane buckling. The structure is found to be metallic with a finite density of states at the Fermi level. This structure can be rolled into nanotubes in a manner similar to graphene. Combining first- and second-row elements in the Periodic Table to form a one-atom-thick material that is also flat opens up the possibility for studying new physics beyond graphene. The presence of Si will make the surface more reactive and therefore a promising candidate for hydrogen storage.

Modeling of hydrogen/deuterium dynamics and heat generation on palladium nanoparticles for hydrogen storage and solid-state nuclear fusion.

PubMed

Tanabe, Katsuaki

2016-01-01

We modeled the dynamics of hydrogen and deuterium adsorbed on palladium nanoparticles including the heat generation induced by the chemical adsorption and desorption, as well as palladium-catalyzed reactions. Our calculations based on the proposed model reproduce the experimental time-evolution of pressure and temperature with a single set of fitting parameters for hydrogen and deuterium injection. The model we generated with a highly generalized set of formulations can be applied for any combination of a gas species and a catalytic adsorbent/absorbent. Our model can be used as a basis for future research into hydrogen storage and solid-state nuclear fusion technologies.

A fast response hydrogen sensor with Pd metallic grating onto a fiber's end-face

NASA Astrophysics Data System (ADS)

Yan, Haitao; Zhao, Xiaoyan; Zhang, Chao; Li, Qiu-Ze; Cao, Jingxiao; Han, Dao-Fu; Hao, Hui; Wang, Ming

2016-01-01

We demonstrated an integrated hydrogen sensor with Pd metallic grating fabricated on a fiber end-face. The grating consists of three thin metal layers in stacks, Au, WO3 and Pd. The WO3 is used as a waveguide layer between the Pd and Au layer. The Pd layer is etched by using a focused ion beam (FIB) method, forming a Pd metallic grating with period of 450 nm. The sensor is experimentally exposed to hydrogen gas environment. Changing the concentration from 0% to 4% which is the low explosive limit (LEL), the resonant wavelength measured from the reflection experienced 28.10 nm spectral changes in the visible range. The results demonstrated that the sensor is sensitive for hydrogen detection and it has fast response and low temperature effect.

Passivation mechanism in silicon heterojunction solar cells with intrinsic hydrogenated amorphous silicon oxide layers

NASA Astrophysics Data System (ADS)

Deligiannis, Dimitrios; van Vliet, Jeroen; Vasudevan, Ravi; van Swaaij, René A. C. M. M.; Zeman, Miro

2017-02-01

In this work, we use intrinsic hydrogenated amorphous silicon oxide layers (a-SiOx:H) with varying oxygen content (cO) but similar hydrogen content to passivate the crystalline silicon wafers. Using our deposition conditions, we obtain an effective lifetime (τeff) above 5 ms for cO ≤ 6 at. % for passivation layers with a thickness of 36 ± 2 nm. We subsequently reduce the thickness of the layers using an accurate wet etching method to ˜7 nm and deposit p- and n-type doped layers fabricating a device structure. After the deposition of the doped layers, τeff appears to be predominantly determined by the doped layers themselves and is less dependent on the cO of the a-SiOx:H layers. The results suggest that τeff is determined by the field-effect rather than by chemical passivation.

Analytical Models for Variable Density Multilayer Insulation Used in Cryogenic Storage

NASA Technical Reports Server (NTRS)

Hedayat, A.; Hastings, L. J.; Brown, T.

2001-01-01

A unique multilayer insulation concept for orbital cryogenic storage was experimentally evaluated at NASA Marshall Space Flight Center (MSFC) using the Multipurpose Hydrogen Test Bed (MHTB). A combination of foam/Multi layer Insulation (MLI) was used. The MLI (45 layers of Double Aluminized Mylar (DAM) with Dacron net spacers) was designed for an on-orbit storage period of 45 days and included several unique features such as: a variable layer density and larger but fewer DAM perforations for venting during ascent to orbit. The focus of this paper is on analytical modeling of the variable density MLI performance during orbital coast periods. The foam/MLI combination model is considered to have five segments. The first segment represents the foam layer. The second, third, and fourth segments represent the three layers of MLI with different layer densities and number of shields. Finally, the last segment is considered to be a shroud that surrounds the last MLI layer. The hot boundary temperature is allowed to vary from 164 K to 305 K. To simulate MLI performance, two approaches are considered. In the first approach, the variable density MLI is modeled layer by layer while in the second approach, a semi-empirical model is applied. Both models account for thermal radiation between shields, gas conduction, and solid conduction through the separator materials. The heat flux values predicted by each approach are compared for different boundary temperatures and MLI systems with 30, 45, 60, and 75 layers.

Solid fuel volatilization to produce synthesis gas

DOEpatents

Schmidt, Lanny D.; Dauenhauer, Paul J.; Degenstein, Nick J.; Dreyer, Brandon J.; Colby, Joshua L.

2014-07-29

A method comprising contacting a carbon and hydrogen-containing solid fuel and a metal-based catalyst in the presence of oxygen to produce hydrogen gas and carbon monoxide gas, wherein the contacting occurs at a temperature sufficiently high to prevent char formation in an amount capable of stopping production of the hydrogen gas and the carbon monoxide gas is provided. In one embodiment, the metal-based catalyst comprises a rhodium-cerium catalyst. Embodiments further include a system for producing syngas. The systems and methods described herein provide shorter residence time and high selectivity for hydrogen and carbon monoxide.

Hydrogen slush density reference system

NASA Technical Reports Server (NTRS)

Weitzel, D. H.; Lowe, L. T.; Ellerbruch, D. A.; Cruz, J. E.; Sindt, C. F.

1971-01-01

A hydrogen slush density reference system was designed for calibration of field-type instruments and/or transfer standards. The device is based on the buoyancy principle of Archimedes. The solids are weighed in a low-mass container so arranged that solids and container are buoyed by triple-point liquid hydrogen during the weighing process. Several types of hydrogen slush density transducers were developed and tested for possible use as transfer standards. The most successful transducers found were those which depend on change in dielectric constant, after which the Clausius-Mossotti function is used to relate dielectric constant and density.

Standardized Testing Program for Solid-State Hydrogen Storage Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Michael A.; Page, Richard A.

2012-07-30

In the US and abroad, major research and development initiatives toward establishing a hydrogen-based transportation infrastructure have been undertaken, encompassing key technological challenges in hydrogen production and delivery, fuel cells, and hydrogen storage. However, the principal obstacle to the implementation of a safe, low-pressure hydrogen fueling system for fuel-cell powered vehicles remains storage under conditions of near-ambient temperature and moderate pressure. The choices for viable hydrogen storage systems at the present time are limited to compressed gas storage tanks, cryogenic liquid hydrogen storage tanks, chemical hydrogen storage, and hydrogen absorbed or adsorbed in a solid-state material (a.k.a. solid-state storage). Solid-statemore » hydrogen storage may offer overriding benefits in terms of storage capacity, kinetics and, most importantly, safety.The fervor among the research community to develop novel storage materials had, in many instances, the unfortunate consequence of making erroneous, if not wild, claims on the reported storage capacities achievable in such materials, to the extent that the potential viability of emerging materials was difficult to assess. This problem led to a widespread need to establish a capability to accurately and independently assess the storage behavior of a wide array of different classes of solid-state storage materials, employing qualified methods, thus allowing development efforts to focus on those materials that showed the most promise. However, standard guidelines, dedicated facilities, or certification programs specifically aimed at testing and assessing the performance, safety, and life cycle of these emergent materials had not been established. To address the stated need, the Testing Laboratory for Solid-State Hydrogen Storage Technologies was commissioned as a national-level focal point for evaluating new materials emerging from the designated Materials Centers of Excellence (MCoE) according to established and qualified standards. Working with industry, academia, and the U.S. government, SwRI set out to develop an accepted set of evaluation standards and analytical methodologies. Critical measurements of hydrogen sorption properties in the Laboratory have been based on three analytical capabilities: 1) a high-pressure Sievert-type volumetric analyzer, modified to improve low-temperature isothermal analyses of physisorption materials and permit in situ mass spectroscopic analysis of the sample’s gas space; 2) a static, high-pressure thermogravimetric analyzer employing an advanced magnetic suspension electro-balance, glove-box containment, and capillary interface for in situ mass spectroscopic analysis of the sample’s gas space; and 3) a Laser-induced Thermal Desorption Mass Spectrometer (LTDMS) system for high thermal-resolution desorption and mechanistic analyses. The Laboratory has played an important role in down-selecting materials and systems that have emerged from the MCoEs.« less

Influence of hydrogen effusion from hydrogenated silicon nitride layers on the regeneration of boron-oxygen related defects in crystalline silicon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilking, S., E-mail: Svenja.Wilking@uni-konstanz.de; Ebert, S.; Herguth, A.

The degradation effect boron doped and oxygen-rich crystalline silicon materials suffer from under illumination can be neutralized in hydrogenated silicon by the application of a regeneration process consisting of a combination of slightly elevated temperature and carrier injection. In this paper, the influence of variations in short high temperature steps on the kinetics of the regeneration process is investigated. It is found that hotter and longer firing steps allowing an effective hydrogenation from a hydrogen-rich silicon nitride passivation layer result in an acceleration of the regeneration process. Additionally, a fast cool down from high temperature to around 550 °C seems tomore » be crucial for a fast regeneration process. It is suggested that high cooling rates suppress hydrogen effusion from the silicon bulk in a temperature range where the hydrogenated passivation layer cannot release hydrogen in considerable amounts. Thus, the hydrogen content of the silicon bulk after the complete high temperature step can be increased resulting in a faster regeneration process. Hence, the data presented here back up the theory that the regeneration process might be a hydrogen passivation of boron-oxygen related defects.« less

Electron-stimulated reactions in nanoscale water films adsorbed on α-Al 2O 3 (0001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrik, Nikolay G.; Kimmel, Gregory A.

The radiation-induced decomposition and desorption of nanoscale amorphous solid water (D2O) films adsorbed on -Al2O3(0001) surface was studied at low temperature in ultrahigh vacuum using temperature programmed desorption (TPD) and electron stimulated desorption (ESD) with a mono-energetic, low energy electron source. ESD yields of molecular products ( D2, O2 and D¬2O) and the total sputtering yield increased with increasing D2O coverage up to ~15 water monolayers (i.e. ~15 1015 cm-2) to a coverage-independent level for thicker water films. Experiments with isotopically-layered water films (D2O and H2O) demonstrated that the highest water decomposition yields occurred at the interfaces of the nanoscalemore » water films with the alumina substrate and vacuum. However, the increased reactivity of the water/alumina interface is relatively small compared to the enhancements in the non-thermal reactions previously observed at the water/Pt(111) and water/TiO2(110) interfaces. We propose that the relatively low activity of Al2O3(0001) for the radiation-induced production of molecular hydrogen is associated with lower reactivity of this surface with hydrogen atoms, which are likely precursors for the molecular hydrogen.100 eV electrons are stopped in the H 2O portion of the isotopically-layered nanoscale film on α-Al 2O 3(0001) but D 2is produced at the D 2O/alumina interface by mobile electronic excitations and/or hydronium ions.« less

MultiLayer solid electrolyte for lithium thin film batteries

DOEpatents

Lee, Se -Hee; Tracy, C. Edwin; Pitts, John Roland; Liu, Ping

2015-07-28

A lithium metal thin-film battery composite structure is provided that includes a combination of a thin, stable, solid electrolyte layer [18] such as Lipon, designed in use to be in contact with a lithium metal anode layer; and a rapid-deposit solid electrolyte layer [16] such as LiAlF.sub.4 in contact with the thin, stable, solid electrolyte layer [18]. Batteries made up of or containing these structures are more efficient to produce than other lithium metal batteries that use only a single solid electrolyte. They are also more resistant to stress and strain than batteries made using layers of only the stable, solid electrolyte materials. Furthermore, lithium anode batteries as disclosed herein are useful as rechargeable batteries.

H.sub.2O doped WO.sub.3, ultra-fast, high-sensitivity hydrogen sensors

DOEpatents

Liu, Ping [Denver, CO; Tracy, C Edwin [Golden, CO; Pitts, J Roland [Lakewood, CO; Lee, Se-Hee [Lakewood, CO

2011-03-22

An ultra-fast response, high sensitivity structure for optical detection of low concentrations of hydrogen gas, comprising: a substrate; a water-doped WO.sub.3 layer coated on the substrate; and a palladium layer coated on the water-doped WO.sub.3 layer.

Adsorption, hydrogenation and dehydrogenation of C2H on a CoCu bimetallic layer

NASA Astrophysics Data System (ADS)

Wu, Donghai; Yuan, Jinyun; Yang, Baocheng; Chen, Houyang

2018-05-01

In this paper, adsorption, hydrogenation and dehydrogenation of C2H on a single atomic layer of bimetallic CoCu were investigated using first-principles calculations. The CoCu bimetallic layer is formed by Cu replacement of partial Co atoms on the top layer of a Co(111) surface. Our adsorption and reaction results showed those sites, which have stronger adsorption energy of C2H, possess higher reactivity. The bimetallic layer possesses higher reactivity than either of the pure monometallic layer. A mechanism of higher reactivity of the bimetallic layer is proposed and identified, i.e. in the bimetallic catalyst, the catalytic performance of one component is promoted by the second component, and in our work, the catalytic performance of Co atoms in the bimetallic layer are improved by introducing Cu atoms, lowing the activation barrier of the reaction of C2H. The bimetallic layer could tune adsorption and reaction of C2H by modulating the ratio of Co and Cu. Results of adsorption energies and adsorption configurations reveal that C2H prefers to be adsorbed in parallel on both the pure Co metallic and CoCu bimetallic layers, and Co atoms in subsurface which support the metallic or bimetallic layer have little effect on C2H adsorption. For hydrogenation reactions, the products greatly depend on the concentration and initial positions of hydrogen atoms, and the C2H hydrogenation forming acetylene is more favorable than forming vinylidene in both thermodynamics and kinetics. This study would provide fundamental guidance for hydrocarbon reactions on Co-based and/or Cu-based bimetallic surface chemistry and for development of new bimetallic catalysts.

Glass for Solid State Devices

NASA Technical Reports Server (NTRS)

Bailey, R. F.

1982-01-01

Glass film has low intrinsic compressive stress for isolating active layers of magnetic-bubble and other solid-state devices. Solid-state device structure incorporates low-stress glasses as barrier and spacer layers. Glass layers mechanically isolate substrate, conductor, and nickel/iron layers.

Post-experimental analysis of a solid oxide fuel cell stack using hybrid seals

NASA Astrophysics Data System (ADS)

Thomann, O.; Rautanen, M.; Himanen, O.; Tallgren, J.; Kiviaho, J.

2015-01-01

A post-experimental analysis of a SOFC stack is presented. The stack was operated for 1800 h at 700 °C with air and hydrogen and contained hybrid glass-Thermiculite 866 seals. The goal of this work was to investigate the sealing microstructure and possible corrosion during mid-term operation. It was found that hybrid seals could effectively compensate for manufacturing tolerances of cells and other components due to the compliance of the glass layer. Additionally, different interfaces were investigated for corrosion. Corrosion was not observed at two-phase interfaces such as Crofer 22 APU/glass, glass/electrolyte and glass/Thermiculite 866. The three-phase interface between Crofer 22 APU/glass/hydrogen exhibited no corrosion. Some evidence of non-systematic corrosion was found at the Crofer 22 APU/glass/air interface. The possible reasons for the corrosion are discussed. Lastly, dual exposure to humid hydrogen and air of the 0.2 mm Crofer 22 APU interconnect had no detrimental effect on the corrosion compared to air exposure. Overall the hybrid seals used in combination with the thin interconnects were found to be a promising solution due to the low leak rate and limited material interactions.

Hydrogen-isotope permeation barrier

DOEpatents

Maroni, Victor A.; Van Deventer, Erven H.

1977-01-01

A composite including a plurality of metal layers has a Cu-Al-Fe bronze layer and at least one outer layer of a heat and corrosion resistant metal alloy. The bronze layer is ordinarily intermediate two outer layers of metal such as austenitic stainless steel, nickel alloys or alloys of the refractory metals. The composite provides a barrier to hydrogen isotopes, particularly tritium that can reduce permeation by at least about 30 fold and possibly more below permeation through equal thicknesses of the outer layer material.

Enhanced kinetics of Al{sub 0.97}Ga{sub 0.03}As wet oxidation through the use of hydrogenation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Du, M.; Sagnes, I.; Beaudoin, G.

2006-09-11

This letter reports on a different kinetic behavior of the wet thermal oxidation process resulting in Al{sub x}O{sub y} material depending on the AlAs material growth method, molecular beam epitaxy (MBE) or metal organic vapor phase epitaxy (MOVPE). A higher oxidation rate for MOVPE-grown materia is systemically found. Considering the major role of hydrogen in the wet oxidation reaction, it is believed this observation could be linked with the higher hydrogen residual concentration in MOVPE layers. Using a hydrogen plasma, MBE-grown Al{sub 0.97}Ga{sub 0.03}As layers were hydrogened prior to oxidation. This hydrogenated sample showed a ten times enhanced oxidation ratemore » as compared to the nonhydrogenated Al{sub 0.97}Ga{sub 0.03}As sample. This behavior is mainly attributed to a hydrogen induced modification of the diffusion limited regime, enhancing the diffusion length of oxidizing species and reaction products in the oxidized layers.« less

Effects of hydrogen on majority carrier transport and minority carrier lifetimes in long wavelength infrared HgCdTe on Si

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boieriu, P.; Grein, C.H.; Velicu, S.

2006-02-06

We present the results of using an electron cyclotron resonance (ECR) plasma to incorporate hydrogen into long wavelength infrared HgCdTe layers grown by molecular beam epitaxy. Both as-grown and annealed layers doped in situ with indium were hydrogenated. Secondary ion mass spectroscopy confirmed the incorporation of hydrogen. Hall and photoconductive lifetime measurements were used to assess the effects of the hydrogenation. Increases in the electron mobilities and minority carrier lifetimes were observed for almost all ECR conditions.

Combination moisture and hydrogen getter

DOEpatents

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.

Combination moisture and hydrogen getter

DOEpatents

Harrah, Larry A.; Mead, Keith E.; Smith, Henry M.

1983-01-01

A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) 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.

Combination moisture and hydrogen getter

DOEpatents

Not Available

1982-04-29

A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) 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 reusltant hydrogen.

Re-fermentation of washed spent solids from batch hydrogenogenic fermentation for additional production of biohydrogen from the organic fraction of municipal solid waste.

PubMed

Muñoz-Páez, Karla M; Ríos-Leal, Elvira; Valdez-Vazquez, Idania; Rinderknecht-Seijas, Noemí; Poggi-Varaldo, Héctor M

2012-03-01

In the first batch solid substrate anaerobic hydrogenogenic fermentation with intermittent venting (SSAHF-IV) of the organic fraction of municipal solid waste (OFMSW), a cumulative production of 16.6 mmol H(2)/reactor was obtained. Releases of hydrogen partial pressure first by intermittent venting and afterward by flushing headspace of reactors with inert gas N(2) allowed for further hydrogen production in a second to fourth incubation cycle, with no new inoculum nor substrate nor inhibitor added. After the fourth cycle, no more H(2) could be harvested. Interestingly, accumulated hydrogen in 4 cycles was 100% higher than that produced in the first cycle alone. At the end of incubation, partial pressure of H(2) was near zero whereas high concentrations of organic acids and solvents remained in the spent solids. So, since approximate mass balances indicated that there was still a moderate amount of biodegradable matter in the spent solids we hypothesized that the organic metabolites imposed some kind of inhibition on further fermentation of digestates. Spent solids were washed to eliminate organic metabolites and they were used in a second SSAHF-IV. Two more cycles of H(2) production were obtained, with a cumulative production of ca. 2.4 mmol H(2)/mini-reactor. As a conclusion, washing of spent solids of a previous SSAHF-IV allowed for an increase of hydrogen production by 15% in a second run of SSAHF-IV, leading to the validation of our hypothesis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Investigation for the amorphous state of ER-34122, a dual 5-lipoxygenase/cyclooxygenase inhibitor with poor aqueous solubility, in HPMC solid dispersion prepared by the solvent evaporation method.

PubMed

Kushida, Ikuo; Gotoda, Masaharu

2013-10-01

ER-34122, a poorly water-soluble dual 5-lipoxygenase/cyclooxygenase inhibitor, exists as a crystalline form. According to an Oak Ridge thermal ellipsoid plot drawing, carbonyl oxygen O (5) makes an intermolecular hydrogen bond with the hydrogen bonded to N (3) in the crystal structure. The FTIR and the solid-state ¹³C NMR spectra suggest that the network is spread out in the amorphous state and the hydrogen bonding gets weaker than that in the crystalline phase, because the carbonyl signals significantly shift in both spectra. When amorphous ER-34122 was heated, crystallization occurred at around 140°C. Similar crystallization happened in the solid dispersion; however, the degree of crystallization was much lower than that observed in the pure amorphous material. Also, the DSC thermogram of the solid dispersion did not show any exothermic peaks implying crystallization. The heat of fusion (ΔHf) determined in the pure amorphous material was nearly equal to that for the crystalline form, whereas the ΔHf value obtained in the solid dispersion was less than a third of them. These data prove that crystallization of the amorphous form is dramatically restrained in the solid dispersion system. The carbonyl wavenumber shifts in the FTIR spectra indicate that the average hydrogen bond in the solid dispersion is lower than that in the pure amorphous material. Therefore, HPMC will suppress formation of the intermolecular network observed in ER-34122 crystal and preserve the amorphous state, which is thermodynamically less stable, in the solid dispersed system.

Use of π-π forces to steer the assembly of a NTA complex of Cu(II) into hydrogen bonded supramolecular layers (H 3NTA = nitrilotriacetic acid)

NASA Astrophysics Data System (ADS)

Dey, Biswajit; Choudhury, Somnath Ray; Suresh, Eringathodi; Jana, Atish Dipankar; Mukhopadhyay, Subrata

2009-03-01

We propose a crystal engineering principle where we show that it might be possible to direct the organization of molecular complexes into hydrogen bonded supramolecular layers through the use of suitable co-ligands possessing both the hydrogen-bonding as well as π-π stacking capability. This principle has been tested for the organization of [Cu(NTA) 2] units (H 3NTA = nitrilotriacetic acid, N(CH 2CO 2H) 3) in the molecular complex with formula (2-A-PH) 4[Cu(NTA) 2]·6H 2O ( 1), where 2-A-PH is protonated 2-amino-4-picoline. In 1, the 2-amino-4-picoline co-ligands have been utilized to direct the organization of [Cu(NTA) 2] units into hydrogen bonded layers. The linear stacking of π-π bonded protonated 2-amino-4-picoline molecules can be thought as the influencing agent for the organization of [Cu(NTA) 2] units into hydrogen bonded layers.

Ab initio study of structural and mechanical property of solid molecular hydrogens

NASA Astrophysics Data System (ADS)

Ye, Yingting; Yang, Li; Yang, Tianle; Nie, Jinlan; Peng, Shuming; Long, Xinggui; Zu, Xiaotao; Du, Jincheng

2015-06-01

Ab initio calculations based on density functional theory (DFT) were performed to investigate the structural and the elastic properties of solid molecular hydrogens (H2). The influence of molecular axes of H2 on structural relative stabilities of hexagonal close-packed (hcp) and face-centered cubic (fcc) structured hydrogen molecular crystals were systematically investigated. Our results indicate that for hcp structures, disordered hydrogen molecule structure is more stable, while for fcc structures, Pa3 hydrogen molecular crystal is most stable. The cohesive energy of fcc H2 crystal was found to be lower than hcp. The mechanical properties of fcc and hcp hydrogen molecular crystals were obtained, with results consistent with previous theoretical calculations. In addition, the effects of zero point energy (ZPE) and van der Waals (vdW) correction on the cohesive energy and the stability of hydrogen molecular crystals were systematically studied and discussed.

Process for the liquefaction of solid carbonaceous materials wherein nitrogen is separated from hydrogen via ammonia synthesis

DOEpatents

Stetka, Steven S.; Nazario, Francisco N.

1982-01-01

In a process for the liquefaction of solid carbonaceous materials wherein bottoms residues are upgraded with a process wherein air is employed, the improvement wherein nitrogen buildup in the system is avoided by ammonia synthesis. In a preferred embodiment hydrogen from other portions of the liquefaction process will be combined with hydrogen produced as a result of the bottoms upgrading to increase the H.sub.2 :N.sub.2 ratio in the ammonia reactor.

Epitaxial thin films

DOEpatents

Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

2006-04-25

Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

PubMed Central

Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

2014-01-01

The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nan, Yue; Tavlarides, Lawrence L.; DePaoli, David W.

The adsorption process of iodine, a major volatile radionuclide in the off-gas streams of spent nuclear fuel reprocessing, on hydrogen-reduced silver-exchanged mordenite (Ag 0Z) was studied at the micro-scale. The gas-solid mass transfer and reaction involved in the adsorption process were investigated and evaluated with appropriate models. Optimal conditions for reducing the silver-exchanged mordenite (AgZ) in a hydrogen stream were determined. Kinetic and equilibrium data of iodine adsorption on Ag 0Z were obtained by performing single-layer adsorption experiments with experimental systems of high precision at 373–473 K over various iodine concentrations. Results indicate approximately 91% to 97% of the iodinemore » adsorption was through the silver-iodine reaction. The effect of temperature on the iodine loading capacity of Ag 0Z was discussed. In conclusion, the Shrinking Core model describes the data well, and the primary rate controlling mechanisms were macro-pore diffusion and silver-iodine reaction. © 2016 American Institute of Chemical Engineers AIChE J, 2016« less

Measurements of the Activation Energies for Atomic Hydrogen Diffusion on Pure Solid CO

NASA Astrophysics Data System (ADS)

Kimura, Y.; Tsuge, M.; Pirronello, V.; Kouchi, A.; Watanabe, N.

2018-05-01

The diffusion of hydrogen atoms on dust grains is a key process in the formation of interstellar H2 and some hydrogenated molecules such as formaldehyde and methanol. We investigate the adsorption and diffusion of H atoms on pure solid CO as an analog of dust surfaces observed toward some cold interstellar regions. Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods to detect H atoms directly, the relative adsorption probabilities and diffusion coefficients of the H atoms are measured on pure solid CO at 8, 12, and 15 K. There is little difference between the diffusion coefficients of the hydrogen and deuterium atoms, indicating that the diffusion is limited by thermal hopping. The activation energies controlling the H-atom diffusion depend on the surface temperature, and values of 22, 30, and ∼37 meV were obtained for 8, 12, and 15 K, respectively.

Feasibility of solid oxide fuel cell dynamic hydrogen coproduction to meet building demand

NASA Astrophysics Data System (ADS)

Shaffer, Brendan; Brouwer, Jacob

2014-02-01

A dynamic internal reforming-solid oxide fuel cell system model is developed and used to simulate the coproduction of electricity and hydrogen while meeting the measured dynamic load of a typical southern California commercial building. The simulated direct internal reforming-solid oxide fuel cell (DIR-SOFC) system is controlled to become an electrical load following device that well follows the measured building load data (3-s resolution). The feasibility of the DIR-SOFC system to meet the dynamic building demand while co-producing hydrogen is demonstrated. The resulting thermal responses of the system to the electrical load dynamics as well as those dynamics associated with the filling of a hydrogen collection tank are investigated. The DIR-SOFC system model also allows for resolution of the fuel cell species and temperature distributions during these dynamics since thermal gradients are a concern for DIR-SOFC.

Preparation and Evaluation of Multi-Layer Anodes of Solid Oxide Fuel Cell

NASA Technical Reports Server (NTRS)

Santiago, Diana; Farmer, Serene C.; Setlock, John A.

2012-01-01

The development of an energy device with abundant energy generation, ultra-high specific power density, high stability and long life is critical for enabling longer missions and for reducing mission costs. Of all different types of fuel cells, the solid oxide fuel cells (SOFC) is a promising high temperature device that can generate electricity as a byproduct of a chemical reaction in a clean way and produce high quality heat that can be used for other purposes. For aerospace applications, a power-to-weight of (is) greater than 1.0 kW/kg is required. NASA has a patented fuel cell technology under development, capable of achieving the 1.0 kW/kg figure of merit. The first step toward achieving these goals is increasing anode durability. The catalyst plays an important role in the fuel cells for power generation, stability, efficiency and long life. Not only the anode composition, but its preparation and reduction are key to achieving better cell performance. In this research, multi-layer anodes were prepared varying the chemistry of each layer to optimize the performance of the cells. Microstructure analyses were done to the new anodes before and after fuel cell operation. The cells' durability and performance were evaluated in 200 hrs life tests in hydrogen at 850 C. The chemistry of the standard nickel anode was modified successfully reducing the anode degradation from 40% to 8.4% in 1000 hrs and retaining its microstructure.

Can Csbnd H⋯Fsbnd C hydrogen bonds alter crystal packing features in the presence of Nsbnd H⋯Odbnd C hydrogen bond?

NASA Astrophysics Data System (ADS)

Yadav, Hare Ram; Choudhury, Angshuman Roy

2017-12-01

Intermolecular interactions involving organic fluorine have been the contemporary field of research in the area of organic solid state chemistry. While a group of researchers had refuted the importance of "organic fluorine" in guiding crystal structures, others have provided evidences for in favor of fluorine mediated interactions in the solid state. Many systematic studies have indicated that the "organic fluorine" is capable of offering weak hydrogen bonds through various supramolecular synthons, mostly in the absence of other stronger hydrogen bonds. Analysis of fluorine mediated interaction in the presence of strong hydrogen bonds has not been highlighted in detail. Hence a thorough structural investigation is needed to understand the role of "organic fluorine" in crystal engineering of small organic fluorinated molecules having the possibility of strong hydrogen bond formation in the solution and in the solid state. To fulfil this aim, we have synthesized a series of fluorinated amides using 3-methoxyphenylacetic acid and fluorinated anilines and studied their structural properties through single crystal and powder X-ray diffraction methods. Our results indicated that the "organic fluorine" plays a significant role in altering the packing characteristics of the molecule in building specific crystal lattices even in the presence of strong hydrogen bond.

Ultraslow Phase Transitions in an Anion-Anion Hydrogen-Bonded Ionic Liquid.

PubMed

Faria, Luiz F O; Lima, Thamires A; Ferreira, Fabio F; Ribeiro, Mauro C C

2018-02-15

A Raman spectroscopy study of 1-ethyl-3-methylimidazolium hydrogen sulfate, [C 2 C 1 im][HSO 4 ], as a function of temperature, has been performed to reveal the role played by anion-anion hydrogen bond on the phase transitions of this ionic liquid. Anion-anion hydrogen bonding implies high viscosity, good glass-forming ability, and also moderate fragility of [C 2 C 1 im][HSO 4 ] in comparison with other ionic liquids. Heating [C 2 C 1 im][HSO 4 ] from the glassy phase results in cold crystallization at ∼245 K. A solid-solid transition (crystal I → crystal II) is barely discernible in calorimetric measurements at typical heating rates, but it is clearly revealed by Raman spectroscopy and X-ray diffraction. Raman spectroscopy indicates that crystal I has extended ([HSO 4 ] - ) n chains of hydrogen-bonded anions but crystal II has not. Raman spectra recorded at isothermal condition show the ultraslow dynamics of cold crystallization, solid-solid transition, and continuous melting of [C 2 C 1 im][HSO 4 ]. A brief comparison is also provided between [C 2 C 1 im][HSO 4 ] and [C 4 C 1 im][HSO 4 ], as Raman spectroscopy shows that the latter does not form the crystalline phase with extended anion-anion chains.

CO2 in solid para-hydrogen: spectral splitting and the CO2···(o-H2)n clusters.

PubMed

Du, Jun-He; Wan, Lei; Wu, Lei; Xu, Gang; Deng, Wen-Ping; Liu, An-Wen; Chen, Yang; Hu, Shui-Ming

2011-02-17

Complicated high-resolution spectral structures are often observed for molecules doped in solid molecular hydrogen. The structures can result from miscellaneous effects and are often interpreted differently in references. The spectrum of the ν(3) band of CO(2) in solid para-H(2) presents a model system which exhibits rich spectral structures. With the help of the potential energy simulation of the CO(2) molecule doped in para-hydrogen matrix, and extensive experiments with different CO(2) isotopologues and different ortho-hydrogen concentrations in the matrix, the spectral features observed in p-H(2) matrix are assigned to the CO(2)···(o-H(2))(n) clusters and also to energy level splitting that is due to different alignments of the doped CO(2) molecules in the matrix. The assignments are further supported by the dynamics analysis and also by the spectrum recorded with sample codoped with O(2) which serves as catalyst transferring o-H(2) to p-H(2) in the matrix at 4 K temperature. The observed spectral features of CO(2)/pH(2) can potentially be used as an alternative readout of the temperature and orthohydrogen concentration in the solid para-hydrogen.

Structural consequences of hydrogen intercalation of epitaxial graphene on SiC(0001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emery, Jonathan D., E-mail: jdemery@anl.gov, E-mail: bedzyk@northwestern.edu; Johns, James E.; McBriarty, Martin E.

2014-10-20

The intercalation of various atomic species, such as hydrogen, to the interface between epitaxial graphene (EG) and its SiC substrate is known to significantly influence the electronic properties of the graphene overlayers. Here, we use high-resolution X-ray reflectivity to investigate the structural consequences of the hydrogen intercalation process used in the formation of quasi-free-standing (QFS) EG/SiC(0001). We confirm that the interfacial layer is converted to a layer structurally indistinguishable from that of the overlying graphene layers. This newly formed graphene layer becomes decoupled from the SiC substrate and, along with the other graphene layers within the film, is vertically displacedmore » by ∼2.1 Å. The number of total carbon layers is conserved during the process, and we observe no other structural changes such as interlayer intercalation or expansion of the graphene d-spacing. These results clarify the under-determined structure of hydrogen intercalated QFS-EG/SiC(0001) and provide a precise model to inform further fundamental and practical understanding of the system.« less

Desulfurization apparatus and method

DOEpatents

Rong, Charles; Jiang, Rongzhong; Chu, Deryn

2013-06-18

A method and system for desulfurization comprising first and second metal oxides; a walled enclosure having an inlet and an exhaust for the passage of gas to be treated; the first and second metal oxide being combinable with hydrogen sulfide to produce a reaction comprising a sulfide and water; the first metal oxide forming a first layer and the second metal oxide forming a second layer within the walled surroundings; the first and second layers being positioned so the first layer removes the bulk amount of the hydrogen sulfide from the treated gas prior to passage through the second layer, and the second layer removes substantially all of the remaining hydrogen sulfide from the treated gas; the first metal oxide producing a stoichiometrical capacity in excess of 500 mg sulfur/gram; the second metal oxide reacts with the hydrogen sulfide more favorably but has a stoichometrical capacity which is less than the first reactant; whereby the optimal amount by weight of the first and second metal oxides is achieved by utilizing two to three units by weight of the first metal oxide for every unit of the second metal oxide.

Japan's Sunshine Project

NASA Astrophysics Data System (ADS)

1992-07-01

A summary report is given on the results of hydrogen energy research and development achieved during 1991 under the Sunshine Project. In hydrogen manufacturing, regenerative cells that can also generate power as fuel cells were discussed by using solid macromolecular electrolytic films for the case where no electrolysis is carried out with water electrolysis. Yttria stabilized zirconia (YSZ), an oxide solid electrolyte was used for the basic research on high-temperature steam electrolysis. Compositions of hydrogen storage alloys and their deterioration mechanisms were investigated to develop hydrogen transportation and storage technologies. High-density hydrides were searched, and fluidization due to paraffin was discussed. Electrode materials and forming technologies were discussed to develop a hydrogen to power conversion system using hydrogen storage alloys as reversible electrodes. Hydrogen-oxygen combustion was studied in terms of reactive theories, and so was the control of ignition and combustion using ultraviolet ray ignition plasma. Studies were made on hydrogen brittlement in welds on materials in hydrogen utilization and its preventive measures. Surveys were given on technical movements and development problems in high-efficiency, pollution-free hydrogen combustion turbines.

Compensated amorphous silicon solar cell

DOEpatents

Devaud, Genevieve

1983-01-01

An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon over said substrate and having regions of differing conductivity with at least one region of intrinsic hydrogenated amorphous silicon. The layer of hydrogenated amorphous silicon has opposed first and second major surfaces where the first major surface contacts the electrically conductive substrate and an electrode for electrically contacting the second major surface. The intrinsic hydrogenated amorphous silicon region is deposited in a glow discharge with an atmosphere which includes not less than about 0.02 atom percent mono-atomic boron. An improved N.I.P. solar cell is disclosed using a BF.sub.3 doped intrinsic layer.

Corrosion characteristics of Ni-base superalloys in high temperature steam with and without hydrogen

NASA Astrophysics Data System (ADS)

Kim, Donghoon; Kim, Daejong; Lee, Ho Jung; Jang, Changheui; Yoon, Duk Joo

2013-10-01

The hot steam corrosion behavior of Alloy 617 and Haynes 230 were evaluated in corrosion tests performed at 900 °C in steam and steam + 20 vol.% H2 environments. Corrosion rates of Alloy 617 was faster than that of Haynes 230 at 900 °C in steam and steam + 20 vol.% H2 environments. When hydrogen was added to steam, the corrosion rate was accelerated because added hydrogen increased the concentration of Cr interstitial defects in the oxide layer. Isolated nodular MnTiO3 oxides were formed on the MnCr2O4/Cr2O3 oxide layer and sub-layer Cr2O3 was formed in steam and steam + 20 vol.% H2 for Alloy 617. On the other hand, a MnCr2O4 layer was formed on top of the Cr2O3 oxide layer for Haynes 230. The extensive sub-layer Cr2O3 formation resulted from the oxygen or hydroxide inward diffusion in such environments. When hydrogen was added, the initial surface oxide morphology was changed from a convex shape to platelets because of the accelerated diffusion of cations under the oxide layer.

The solubility of hydrogen in rhodium, ruthenium, iridium and nickel.

NASA Technical Reports Server (NTRS)

Mclellan, R. B.; Oates, W. A.

1973-01-01

The temperature variation of the solubility of hydrogen in rhodium, ruthenium, iridium, and nickel in equilibrium with H2 gas at 1 atm pressure has been measured by a technique involving saturating the solvent metal with hydrogen, quenching, and analyzing in resultant solid solutions. The solubilities determined are small (atom fraction of H is in the range from 0.0005 to 0.00001, and the results are consistent with the simple quasi-regular model for dilute interstitial solid solutions. The relative partial enthalpy and excess entropy of the dissolved hydrogen atoms have been calculated from the solubility data and compared with well-known correlations between these quantities.

Translational vibrations between chains of hydrogen-bonded molecules in solid-state aspirin form I

NASA Astrophysics Data System (ADS)

Takahashi, Masae; Ishikawa, Yoichi

2013-06-01

We perform dispersion-corrected first-principles calculations, and far-infrared (terahertz) spectroscopic experiments at 4 K, to examine translational vibrations between chains of hydrogen-bonded molecules in solid-state aspirin form I. The calculated frequencies and relative intensities reproduce the observed spectrum to accuracy of 11 cm-1 or less. The stronger one of the two peaks assigned to the translational mode includes the stretching vibration of the weak hydrogen bond between the acetyl groups of a neighboring one-dimensional chain. The calculation of aspirin form II performed for comparison gives the stretching vibration of the weak hydrogen bond in one-dimensional chain.

Cover and startup gas supply system for solid oxide fuel cell generator

DOEpatents

Singh, P.; George, R.A.

1999-07-27

A cover and startup gas supply system for a solid oxide fuel cell power generator is disclosed. Hydrocarbon fuel, such as natural gas or diesel fuel, and oxygen-containing gas are supplied to a burner. Combustion gas exiting the burner is cooled prior to delivery to the solid oxide fuel cell. The system mixes the combusted hydrocarbon fuel constituents with hydrogen which is preferably stored in solid form to obtain a non-explosive gas mixture. The system may be used to provide both non-explosive cover gas and hydrogen-rich startup gas to the fuel cell. 4 figs.

Cover and startup gas supply system for solid oxide fuel cell generator

DOEpatents

Singh, Prabhakar; George, Raymond A.

1999-01-01

A cover and startup gas supply system for a solid oxide fuel cell power generator is disclosed. Hydrocarbon fuel, such as natural gas or diesel fuel, and oxygen-containing gas are supplied to a burner. Combustion gas exiting the burner is cooled prior to delivery to the solid oxide fuel cell. The system mixes the combusted hydrocarbon fuel constituents with hydrogen which is preferably stored in solid form to obtain a non-explosive gas mixture. The system may be used to provide both non-explosive cover gas and hydrogen-rich startup gas to the fuel cell.

Hydrogen-bond Specific Materials Modification in Group IV Semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tolk, Norman H.; Feldman, L. C.; Luepke, G.

Executive summary Semiconductor dielectric crystals consist of two fundamental components: lattice atoms and electrons. The former component provides a crystalline structure that can be disrupted by various defects or the presence of an interface, or by transient oscillations known as phonons. The latter component produces an energetic structure that is responsible for the optical and electronic properties of the material, and can be perturbed by lattice defects or by photo-excitation. Over the period of this project, August 15, 1999 to March 31, 2015, a persistent theme has been the elucidation of the fundamental role of defects arising from the presencemore » of radiation damage, impurities (in particular, hydrogen), localized strain or some combination of all three. As our research effort developed and evolved, we have experienced a few title changes, which reflected this evolution. Throughout the project, ultrafast lasers usually in a pump-probe configuration provided the ideal means to perturb and study semiconductor crystals by both forms of excitation, vibrational (phonon) and electronic (photon). Moreover, we have found in the course of this research that there are many interesting and relevant scientific questions that may be explored when phonon and photon excitations are controlled separately. Our early goals were to explore the dynamics of bond-selective vibrational excitation of hydrogen from point defects and impurities in crystalline and amorphous solids, initiating an investigation into the behavior of hydrogen isotopes utilizing a variety of ultrafast characterization techniques, principally transient bleaching spectroscopy to experimentally obtain vibrational lifetimes. The initiative could be divided into three related areas: (a) investigation of the change in electronic structure of solids due to the presence of hydrogen defect centers, (b) dynamical studies of hydrogen in materials and (c) characterization and stability of metastable hydrogen impurity states under transient compression. This research focused on the characterization of photon and ion stimulated hydrogen related defect and impurity reactions and migration in solid state matter, which requires a detailed understanding of the rates and pathways of vibrational energy flow, of the transfer channels and of the coupling mechanisms between local vibrational modes (LVMs) and phonon bath as well as the electronic system of the host material. It should be stressed that researchers at Vanderbilt and William and Mary represented a unique group with a research focus and capabilities for low temperature creation and investigation of such material systems. Later in the program, we carried out a vigorous research effort addressing the roles of defects, interfaces, and dopants on the optical and electronic characteristics of semiconductor crystals, using phonon generation by means of ultrafast coherent acoustic phonon (CAP) spectroscopy, nonlinear characterization using second harmonic generation (SHG), and ultrafast pump-and-probe reflectivity and absorption measurements. This program featured research efforts from hydrogen defects in silicon alone to other forms of defects such as interfaces and dopant layers, as well as other important semiconducting systems. Even so, the emphasis remains on phenomena and processes far from equilibrium, such as hot electron effects and travelling localized phonon waves. This program relates directly to the mission of the Department of Energy. Knowledge of the rates and pathways of vibrational energy flow in condensed matter is critical for understanding dynamical processes in solids including electronically, optically and thermally stimulated defect and impurity reactions and migration. The ability to directly probe these pathways and rates allows tests of theory and scaling laws at new levels of precision. Hydrogen embedded in model crystalline semiconductors and metal oxides is of particular interest, since the associated local mode can be excited cleanly, and is usually well-separated in energy from the phonon bath. These basic dynamical studies have provided new insights for example into the fundamental mechanisms that control proton diffusion in these oxides. This area of materials science has largely fulfilled its promise to identify degradation mechanisms in electronic and optoelectronic devices, and to advance solid oxide proton conductors for fuel cells, gas sensors and proton-exchange membrane applications. It also provides the basis for innovations in materials synthesis involving atomic-selective diffusion and desorption.« less

Solid-phase microextraction may catalize hydrogenation when using hydrogen as carrier in gas chromatography.

PubMed

Fiorini, D; Boarelli, M C

2016-07-01

When hydrogen is used as carrier gas, carbon-carbon double bonds may be hydrogenated in the hot gas chromatograph (GC) injector if introduced by solid-phase microextraction (SPME). SPME fibers coated with polydimethylsiloxane (PDMS)/carboxen/divinylbenzene (DVB), PDMS/carboxen, polyacrylate, PDMS/DVB and PDMS on fused silica, stableflex or metal alloy core have been tested with fatty acid methyl esters (FAMEs) from olive oil. Using coatings containing DVB, hydrogenation took place with high conversion rates (82.0-92.9%) independently of the core material. With all fibers having a metal core, hydrogenation was observed to a certain extent (27.4-85.3%). PDMS, PDMS/carboxen and polyacrylate coated fibers with a fused silica or stableflex core resulted in negligible hydrogenation (0.2-2.5%). The occurrence of hydrogenation was confirmed also with other substances containing carbon-carbon double bonds (n-alkenes, alkenoic acids, mono- and polyunsaturated fatty acid methyl and ethyl esters). Copyright © 2016 Elsevier B.V. All rights reserved.

Estimation of polymer-surface interfacial interaction strength by a contact AFM technique.

PubMed

Dvir, H; Jopp, J; Gottlieb, M

2006-12-01

Atomic force microscopy (AFM) measurements were employed to assess polymer-surface interfacial interaction strength. The main feature of the measurement is the use of contact-mode AFM as a tool to scratch off the polymer monolayer adsorbed on the solid surface. Tapping-mode AFM was used to determine the depth of the scraped recess. Independent determination of the layer thickness obtained from optical phase interference microscopy (OPIM) confirmed the depth of the AFM scratch. The force required for the complete removal of the polymer layer with no apparent damage to the substrate surface was determined. Polypropylene (PP), low-density polyethylene (PE), and PP-grafted-maleic anhydride (PP-g-ma) were scraped off silane-treated glass slabs, and the strength of surface interaction of the polymer layer was determined. In all cases it was determined that the magnitude of surface interaction force is of the order of van der Waals (VDW) interactions. The interaction strength is influenced either by polymer ability to wet the surface (hydrophobic or hydrophilic interactions) or by hydrogen bonding between the polymer and the surface treatment.

Synthesis, structure and characterization of two new organic template-directed gallium phosphate/phosphite-oxalates

NASA Astrophysics Data System (ADS)

Xue, Zhen-Zhen; Pan, Jie; Li, Jin-Hua; Wang, Zong-Hua; Wang, Guo-Ming

2017-06-01

Two new gallium phosphate/phosphite-oxalates hybrid solids, {[H2dmpip][Ga2(HPO4)2(PO4)(C2O4)0.5]·H2O} (1) and [H2apm][Ga2(H2PO3)2(HPO3)2(C2O4)] (2), where dmpip = 2,6-dimethyl-piperazine and apm = N-(3-aminopropyl)morpholine, have been synthesized and structurally characterized. Both of compounds 1 and 2 are formed by the connectivity of the Ga-based polyhedral, phosphite/phosphate groups as well as oxalate units. Compound 1 possesses a two-dimensional layer structure, in which the C2O4 units via an in-plane linkage connect two Ga center within the sheet. While in 2, the C2O4 units serve as bis-bidentates ligands bridging two GaO6 octahedra from two distinct gallium-phosphite chains to give rise to inorganic-organic hybrid layer with 8-membered rings. In these materials, the structure-directing amines reside in the interlayer region and interact with the layers by way of hydrogen-bonds.

Influence of EDTA in poly(acrylic acid) binder for enhancing electrochemical performance and thermal stability of silicon anode

NASA Astrophysics Data System (ADS)

Lee, Sun-Young; Choi, Yunju; Hong, Kyong-Soo; Lee, Jung Kyoo; Kim, Ju-Young; Bae, Jong-Seong; Jeong, Euh Duck

2018-07-01

The crucial roles of ethylenediaminetetraacetic acid (EDTA) in the poly(acrylic acid) (PAA)-binder system were investigated for the high electrochemical performance silicon anode in lithium-ion batteries. The EDTA supports the construction of a mechanically robust network through the formation of sbndCOOH linkage with the SiO2 layer of the Si nanoparticles. The mixture of the PAA/EDTA binder and the conductive agent exhibited an improved elastic modulus and peeling strength. The creation of hydrogen fluoride (HF) was effectively suppressed through the elimination of the H2O. An H2O-phosphorous pentafluoride (PF5) reaction, which is known for its use in the etching of metal oxides including its creation of the solid electrolyte interphase (SEI) layer, generates the HF. A remarkably sound cyclability with a discharge capacity of 2540 mA h g-1 was achieved as a result of the synergistic effect between robust mechanical properties and suppression of the HF creation for the stability of the SEI layer.

Sustained release and permeation of timolol from surface-modified solid lipid nanoparticles through bioengineered human cornea.

PubMed

Attama, A A; Reichl, S; Müller-Goymann, C C

2009-08-01

The aim of the study was to formulate and evaluate surface-modified solid lipid nanoparticles sustained delivery system of timolol hydrogen maleate, a prototype ocular drug using a human cornea construct. Surface-modified solid lipid nanoparticles containing timolol with and without phospholipid were formulated by melt emulsification with high-pressure homogenization and characterized by particle size, wide-angle X-ray diffraction, encapsulation efficiency, and in vitro drug release. Drug transport studies through cornea bioengineered from human donor cornea cells were carried out using a modified Franz diffusion cell and drug concentration analyzed by high-performance liquid chromatography. Results show that surface-modified solid lipid nanoparticles possessed very small particles (42.9 +/- 0.3 nm, 47.2 +/- 0.3 nm, 42.7 +/- 0.7 nm, and 37.7 +/- 0.3 nm, respectively for SM-SLN 1, SM-SLN 2, SM-SLN 3, and SM-SLN 4) with low polydispersity indices, increased encapsulation efficiency (> 44%), and sustained in vitro release compared with unmodified lipid nanoparticles whose particles were greater than 160 nm. Permeation of timolol hydrogen maleate from the surface-modified lipid nanoparticles across the cornea construct was sustained compared with timolol hydrogen maleate solution in distilled water. Surface-modified solid lipid nanoparticles could provide an efficient way of improving ocular bioavailability of timolol hydrogen maleate.

Hydrogen speciation in hydrated layers on nuclear waste glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aines, R.D.; Weed, H.C.; Bates, J.K.

1987-12-31

The hydration of an outer layer on nuclear waste glasses in known to occur during leaching, but the actual speciation of hydrogen (as water or hydroxyl groups) in these layers has not been determined. As part of the Nevada Nuclear Waste Storage Investigations Project, we have used infrared spectroscopy to determine hydrogen speciations in three nuclear waste glass compositions (SRL-131 & 165, and PNL 76-68), which were leached at 90{sup 0}C (all glasses) or hydrated in a vapor-saturated atmosphere at 202{sup 0}C (SRL-131 only). Hydroxyl groups were found in the surface layers of all the glasses. In addition, molecular watermore » was found in the surface of SRL-131 and PNL 76-68 glasses that had been leached for several months in deionized water, and in the vapor-hydrated sample. The water/hydroxyl ratio increases with increasing reaction time; molecular water makes up most of the hydrogen in the thick reaction layers on vapor-phase hydrated glass while only hydroxyl occurs in the least reacted samples. The hydrated layer on the nuclear waste glasses appears to be of relatively low water content (4 to 7% by weight) and is not substantially hydroxylated. Thus, these layers do not have many of the properties associated with gel layers.« less

System for rapid biohydrogen phenotypic screening of microorganisms using a chemochromic sensor

DOEpatents

Seibert, Michael; Benson, David K.; Flynn, Timothy Michael

2002-01-01

Provided is a system for identifying a hydrogen gas producing organism. The system includes a sensor film having a first layer comprising a transition metal oxide or oxysalt and a second layer comprising a hydrogen-dissociative catalyst metal, the first and second layers having an inner and an outer surface wherein the inner surface of the second layer is deposited on the outer surface of the first layer, and a substrate adjacent to the outer surface of the second layer, the organism isolated on the substrate.

Method and apparatus for rapid biohydrogen phenotypic screening of microorganisms using a chemochromic sensor

DOEpatents

Seibert, Michael; Benson, David K.; Flynn, Timothy Michael

2001-01-01

The invention provides an assay system for identifying a hydrogen-gas-producing organism, including a sensor film having a first layer comprising a transition metal oxide or oxysalt and a second layer comprising hydrogen-dissociative catalyst metal, the first and second layers having an inner and an outer surface wherein the inner surface of the second layer is deposited on the outer surface of the first layer, and a substrate disposed proximally to the outer surface of the second layer, the organism being isolated on the substrate.

Rechargeable solid polymer electrolyte battery cell

DOEpatents

Skotheim, Terji

1985-01-01

A rechargeable battery cell comprising first and second electrodes sandwiching a solid polymer electrolyte comprising a layer of a polymer blend of a highly conductive polymer and a solid polymer electrolyte adjacent said polymer blend and a layer of dry solid polymer electrolyte adjacent said layer of polymer blend and said second electrode.

Photocatalytic activity and reusability of ZnO layer synthesised by electrolysis, hydrogen peroxide and heat treatment.

PubMed

Akhmal Saadon, Syaiful; Sathishkumar, Palanivel; Mohd Yusoff, Abdull Rahim; Hakim Wirzal, Mohd Dzul; Rahmalan, Muhammad Taufiq; Nur, Hadi

2016-08-01

In this study, the zinc oxide (ZnO) layer was synthesised on the surface of Zn plates by three different techniques, i.e. electrolysis, hydrogen peroxide and heat treatment. The synthesised ZnO layers were characterised using scanning electron microscopy, X-ray diffraction, UV-visible diffuse reflectance and photoluminescence spectroscopy. The photocatalytic activity of the ZnO layer was further assessed against methylene blue (MB) degradation under UV irradiation. The photocatalytic degradation of MB was achieved up to 84%, 79% and 65% within 1 h for ZnO layers synthesised by electrolysis, heat and hydrogen peroxide treatment, respectively. The reusability results show that electrolysis and heat-treated ZnO layers have considerable photocatalytic stability. Furthermore, the results confirmed that the photocatalytic efficiency of ZnO was directly associated with the thickness and enlarged surface area of the layer. Finally, this study proved that the ZnO layers synthesised by electrolysis and heat treatment had shown better operational stability and reusability.

First-principles quantum-mechanical investigations of biomass conversion at the liquid-solid interfaces

NASA Astrophysics Data System (ADS)

Dang, Hongli; Xue, Wenhua; Liu, Yingdi; Jentoft, Friederike; Resasco, Daniel; Wang, Sanwu

2014-03-01

We report first-principles density-functional calculations and ab initio molecular dynamics (MD) simulations for the reactions involving furfural, which is an important intermediate in biomass conversion, at the catalytic liquid-solid interfaces. The different dynamic processes of furfural at the water-Cu(111) and water-Pd(111) interfaces suggest different catalytic reaction mechanisms for the conversion of furfural. Simulations for the dynamic processes with and without hydrogen demonstrate the importance of the liquid-solid interface as well as the presence of hydrogen in possible catalytic reactions including hydrogenation and decarbonylation of furfural. Supported by DOE (DE-SC0004600). This research used the supercomputer resources of the XSEDE, the NERSC Center, and the Tandy Supercomputing Center.

Liquid-solid phase transition of hydrogen and deuterium in silica aerogel

NASA Astrophysics Data System (ADS)

Van Cleve, E.; Worsley, M. A.; Kucheyev, S. O.

2014-10-01

Behavior of hydrogen isotopes confined in disordered low-density nanoporous solids remains essentially unknown. Here, we use relaxation calorimetry to study freezing and melting of H2 and D2 in an ˜85%-porous base-catalyzed silica aerogel. We find that liquid-solid transition temperatures of both isotopes inside the aerogel are depressed. The phase transition takes place over a wide temperature range of ˜4 K and non-trivially depends on the liquid filling fraction, reflecting the broad pore size distribution in the aerogel. Undercooling is observed for both H2 and D2 confined inside the aerogel monolith. Results for H2 and D2 are extrapolated to tritium-containing hydrogens with the quantum law of corresponding states.

Materials Engineering and Scale Up of Fluid Phase Chemical Hydrogen Storage for Automotive Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westman, Matthew P.; Chun, Jaehun; Choi, Young Joon

Among candidates for chemical hydrogen storage in PEM fuel cell automotive applications, ammonia borane (AB, NH3BH3) is considered to be one of the most promising materials due to its high hydrogen content of 14-16 wt% below 200°C and high volumetric density. In our previous paper, we selected AB in silicone oil as a role model for a slurry hydrogen storage system. Materials engineering properties were optimized by increasing solid loading by using an ultra-sonic process. In this paper, we proceeded to scale up to liter size batches with solid loadings up to 50 wt% (8 wt% H2) with dynamic viscositiesmore » less than 1000cP at 25°C. The use of a non-ionic surfactant, Triton X-15, shows significant promise in controlling the level of foaming produced during the thermal dehydrogenation of the AB. Through the development of new and efficient processing techniques and the ability to adequately control the foaming, stable homogenous slurries of high solid loading have been demonstrated as a viable hydrogen delivery source.« less

The role of hydrogenated amorphous silicon oxide buffer layer on improving the performance of hydrogenated amorphous silicon germanium single-junction solar cells

NASA Astrophysics Data System (ADS)

Sritharathikhun, Jaran; Inthisang, Sorapong; Krajangsang, Taweewat; Krudtad, Patipan; Jaroensathainchok, Suttinan; Hongsingtong, Aswin; Limmanee, Amornrat; Sriprapha, Kobsak

2016-12-01

Hydrogenated amorphous silicon oxide (a-Si1-xOx:H) film was used as a buffer layer at the p-layer (μc-Si1-xOx:H)/i-layer (a-Si1-xGex:H) interface for a narrow band gap hydrogenated amorphous silicon germanium (a-Si1-xGex:H) single-junction solar cell. The a-Si1-xOx:H film was deposited by plasma enhanced chemical vapor deposition (PECVD) at 40 MHz in a same processing chamber as depositing the p-type layer. An optimization of the thickness of the a-Si1-xOx:H buffer layer and the CO2/SiH4 ratio was performed in the fabrication of the a-Si1-xGex:H single junction solar cells. By using the wide band gap a-Si1-xOx:H buffer layer with optimum thickness and CO2/SiH4 ratio, the solar cells showed an improvement in the open-circuit voltage (Voc), fill factor (FF), and short circuit current density (Jsc), compared with the solar cells fabricated using the conventional a-Si:H buffer layer. The experimental results indicated the excellent potential of the wide-gap a-Si1-xOx:H buffer layers for narrow band gap a-Si1-xGex:H single junction solar cells.

Cu-PDC-bpa solid coordination frameworks (PDC=2,5-pyrindinedicarboxylate; bpa=1,2-DI(4-pyridil)ethane)): 2D and 3D structural flexibility producing a 3-c herringbone array next to ideal

NASA Astrophysics Data System (ADS)

Llano-Tomé, Francisco; Bazán, Begoña; Urtiaga, Miren-Karmele; Barandika, Gotzone; Antonia Señarís-Rodríguez, M.; Sánchez-Andújar, Manuel; Arriortua, María-Isabel

2015-10-01

Combination of polycarboxylate anions and dipyridyl ligands is an effective strategy to produce solid coordination frameworks (SCF) which are crystalline materials based on connections between metal ions through organic ligands. In this context, this work is focused on two novel CuII-based SCFs exhibiting PDC (2,5-pyridinedicarboxylate) and bpa (1,2-di(4-pyridyl)ethane), being the first structures reported in literature containing both ligands. Chemical formula are [Cu2[(PDC)2(bpa)(H2O)2]·3H2O·DMF (1), and [Cu2(PDC)2(bpa)(H2O)2]·7H2O (2), where DMF is dimethylformamide. Compounds 1 and 2 have been characterized by means of X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric (TG) analysis, differential thermal analysis (DTA) and dielectric measurements. The crystallographic analysis revealed that compounds 1 and 2 can be described as herringbone-type layers formed by helicoidal Cu-PDC-Cu chains connected through bpa ligands. Solvent molecules are crystallized between the layers, providing the inter-layer connections through hydrogen bonds. Differences between both compounds are attributable to the flexibility of bpa (in 2D) as well as to the 3D packing of the layers which is solvent dependent. This fact results in the fact that compound 2 is the most regular 3-c herringbone array reported so far. The structural dynamism of these networks is responsible for the crystalline to-amorphous to-crystalline (CAC) transformation from compound 1 to compound 2. Crystallochemical features for both compounds have also been studied and compared to similar 3-connected herringbone-arrays.

Hydrogen Generator

NASA Technical Reports Server (NTRS)

1983-01-01

A unit for producing hydrogen on site is used by a New Jersey Electric Company. The hydrogen is used as a coolant for the station's large generator; on-site production eliminates the need for weekly hydrogen deliveries. High purity hydrogen is generated by water electrolysis. The electrolyte is solid plastic and the control system is electronic. The technology was originally developed for the Gemini spacecraft.

Water Transport in the Micro Porous Layer and Gas Diffusion Layer of a Polymer Electrolyte Fuel Cell

NASA Astrophysics Data System (ADS)

Qin, C.; Hassanizadeh, S. M.

2015-12-01

In this work, a recently developed dynamic pore-network model is presented [1]. The model explicitly solves for both water pressure and capillary pressure. A semi-implicit scheme is used in updating water saturation in each pore body, which considerably increases the numerical stability at low capillary number values. Furthermore, a multiple-time-step algorithm is introduced to reduce the computational effort. A number of case studies of water transport in the micro porous layer (MPL) and gas diffusion layer (GDL) are conducted. We illustrate the role of MPL in reducing water flooding in the GDL. Also, the dynamic water transport through the MPL-GDL interface is explored in detail. This information is essential to the reduced continua model (RCM), which was developed for multiphase flow through thin porous layers [2, 3]. C.Z. Qin, Water transport in the gas diffusion layer of a polymer electrolyte fuel cell: dynamic pore-network modeling, J Electrochimical. Soci., 162, F1036-F1046, 2015. C.Z. Qin and S.M. Hassanizadeh, Multiphase flow through multilayers of thin porous media: general balance equations and constitutive relationships for a solid-gas-liquid three-phase system, Int. J. Heat Mass Transfer, 70, 693-708, 2014. C.Z. Qin and S.M. Hassanizadeh, A new approach to modeling water flooding in a polymer electrolyte fuel cell, Int. J. Hydrogen Energy, 40, 3348-3358, 2015.

Simple Hydrogen Plasma Doping Process of Amorphous Indium Gallium Zinc Oxide-Based Phototransistors for Visible Light Detection.

PubMed

Kang, Byung Ha; Kim, Won-Gi; Chung, Jusung; Lee, Jin Hyeok; Kim, Hyun Jae

2018-02-28

A homojunction-structured amorphous indium gallium zinc oxide (a-IGZO) phototransistor that can detect visible light is reported. The key element of this technology is an absorption layer composed of hydrogen-doped a-IGZO. This absorption layer is fabricated by simple hydrogen plasma doping, and subgap states are induced by increasing the amount of hydrogen impurities. These subgap states, which lead to a higher number of photoexcited carriers and aggravate the instability under negative bias illumination stress, enabled the detection of a wide range of visible light (400-700 nm). The optimal condition of the hydrogen-doped absorption layer (HAL) is fabricated at a hydrogen partial pressure ratio of 2%. As a result, the optimized a-IGZO phototransistor with the HAL exhibits a high photoresponsivity of 1932.6 A/W, a photosensitivity of 3.85 × 10 6 , and a detectivity of 6.93 × 10 11 Jones under 635 nm light illumination.

Hydrogen production by high temperature water splitting using electron conducting membranes

DOEpatents

Balachandran, Uthamalingam; Wang, Shuangyan; Dorris, Stephen E.; Lee, Tae H.

2006-08-08

A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing protons or hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at dissociation temperatures the hydrogen from the dissociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the dissociation of steam producing hydrogen and oxygen. The oxygen is thereafter reacted with methane to produce syngas which optimally may be reacted in a water gas shift reaction to produce CO₂ and H₂.

High-pressure melting curve of hydrogen.

PubMed

Davis, Sergio M; Belonoshko, Anatoly B; Johansson, Börje; Skorodumova, Natalia V; van Duin, Adri C T

2008-11-21

The melting curve of hydrogen was computed for pressures up to 200 GPa, using molecular dynamics. The inter- and intramolecular interactions were described by the reactive force field (ReaxFF) model. The model describes the pressure-volume equation of state solid hydrogen in good agreement with experiment up to pressures over 150 GPa, however the corresponding equation of state for liquid deviates considerably from density functional theory calculations. Due to this, the computed melting curve, although shares most of the known features, yields considerably lower melting temperatures compared to extrapolations of the available diamond anvil cell data. This failure of the ReaxFF model, which can reproduce many physical and chemical properties (including chemical reactions in hydrocarbons) of solid hydrogen, hints at an important change in the mechanism of interaction of hydrogen molecules in the liquid state.

In situ fabrication of silver nanoparticle-filled hydrogen titanate nanotube layer on metallic titanium surface for bacteriostatic and biocompatible implantation

PubMed Central

Wang, Zheng; Sun, Yan; Wang, Dongzhou; Liu, Hong; Boughton, Robert I

2013-01-01

A silver nanoparticle (AgNP)-filled hydrogen titanate nanotube layer was synthesized in situ on a metallic titanium substrate. In the synthesis approach, a layer of sodium titanate nanotubes is first prepared on the titanium surface by using a hydrothermal method. Silver nitrate solution is absorbed into the nanotube channels by immersing a dried nanotube layer in silver nitrate solution. Finally, silver ions are reduced by glucose, leading to the in situ growth of AgNPs in the hydrogen titanate nanotube channels. Long-term silver release and bactericidal experiments demonstrated that the effective silver release and effective antibacterial period of the titanium foil with a AgNP-filled hydrogen titanate nanotube layer on the surface can extend to more than 15 days. This steady and prolonged release characteristic is helpful to promote a long-lasting antibacterial capability for the prevention of severe infection after surgery. A series of antimicrobial and biocompatible tests have shown that the sandwich nanostructure with a low level of silver loading exhibits a bacteriostatic rate as high as 99.99%, while retaining low toxicity for cells and possessing high osteogenic potential. Titanium foil with a AgNP-filled hydrogen titanate nanotube layer on the surface that is fabricated with low-cost surface modification methods is a promising implantable material that will find applications in artificial bones, joints, and dental implants. PMID:23966780

Hydrogen Atomic Positions of O-H···O Hydrogen Bonds in Solution and in the Solid State: The Synergy of Quantum Chemical Calculations with ¹H-NMR Chemical Shifts and X-ray Diffraction Methods.

PubMed

Siskos, Michael G; Choudhary, M Iqbal; Gerothanassis, Ioannis P

2017-03-07

The exact knowledge of hydrogen atomic positions of O-H···O hydrogen bonds in solution and in the solid state has been a major challenge in structural and physical organic chemistry. The objective of this review article is to summarize recent developments in the refinement of labile hydrogen positions with the use of: (i) density functional theory (DFT) calculations after a structure has been determined by X-ray from single crystals or from powders; (ii) ¹H-NMR chemical shifts as constraints in DFT calculations, and (iii) use of root-mean-square deviation between experimentally determined and DFT calculated ¹H-NMR chemical shifts considering the great sensitivity of ¹H-NMR shielding to hydrogen bonding properties.

Analysis of Material Sample Heated by Impinging Hot Hydrogen Jet in a Non-Nuclear Tester

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Foote, John; Litchford, Ron

2006-01-01

A computational conjugate heat transfer methodology was developed and anchored with data obtained from a hot-hydrogen jet heated, non-nuclear materials tester, as a first step towards developing an efficient and accurate multiphysics, thermo-fluid computational methodology to predict environments for hypothetical solid-core, nuclear thermal engine thrust chamber. The computational methodology is based on a multidimensional, finite-volume, turbulent, chemically reacting, thermally radiating, unstructured-grid, and pressure-based formulation. The multiphysics invoked in this study include hydrogen dissociation kinetics and thermodynamics, turbulent flow, convective and thermal radiative, and conjugate heat transfers. Predicted hot hydrogen jet and material surface temperatures were compared with those of measurement. Predicted solid temperatures were compared with those obtained with a standard heat transfer code. The interrogation of physics revealed that reactions of hydrogen dissociation and recombination are highly correlated with local temperature and are necessary for accurate prediction of the hot-hydrogen jet temperature.

New porous water ice metastable at atmospheric pressure obtained by emptying a hydrogen-filled ice

PubMed Central

del Rosso, Leonardo; Celli, Milva; Ulivi, Lorenzo

2016-01-01

The properties of some forms of water ice reserve still intriguing surprises. Besides the several stable or metastable phases of pure ice, solid mixtures of water with gases are precursors of other ices, as in some cases they may be emptied, leaving a metastable hydrogen-bound water structure. We present here the first characterization of a new form of ice, obtained from the crystalline solid compound of water and molecular hydrogen called C0-structure filled ice. By means of Raman spectroscopy, we measure the hydrogen release at different temperatures and succeed in rapidly removing all the hydrogen molecules, obtaining a new form of ice (ice XVII). Its structure is determined by means of neutron diffraction measurements. Of paramount interest is that the emptied crystal can adsorb again hydrogen and release it repeatedly, showing a temperature-dependent hysteresis. PMID:27819265

Path-integral simulation of solids.

PubMed

Herrero, C P; Ramírez, R

2014-06-11

The path-integral formulation of the statistical mechanics of quantum many-body systems is described, with the purpose of introducing practical techniques for the simulation of solids. Monte Carlo and molecular dynamics methods for distinguishable quantum particles are presented, with particular attention to the isothermal-isobaric ensemble. Applications of these computational techniques to different types of solids are reviewed, including noble-gas solids (helium and heavier elements), group-IV materials (diamond and elemental semiconductors), and molecular solids (with emphasis on hydrogen and ice). Structural, vibrational, and thermodynamic properties of these materials are discussed. Applications also include point defects in solids (structure and diffusion), as well as nuclear quantum effects in solid surfaces and adsorbates. Different phenomena are discussed, as solid-to-solid and orientational phase transitions, rates of quantum processes, classical-to-quantum crossover, and various finite-temperature anharmonic effects (thermal expansion, isotopic effects, electron-phonon interactions). Nuclear quantum effects are most remarkable in the presence of light atoms, so that especial emphasis is laid on solids containing hydrogen as a constituent element or as an impurity.

Process for liquefying carbonaceous materials of high molecular weight and for separating liquefaction products

DOEpatents

Malek, John M.

1977-01-01

Process characterized by comprising successively a dissolution zone fed with carbonaceous solids and with a solvent, a high pressure hydrogenation zone provided with a source of hydrogen, and a hydrogenation products separation zone, wherein the improvement consists mainly in chemical upgrading of the liquidform products derived from the separation zone, and recycling a part of the upgraded products to the dissolution zone, this recycled part being of either positively acidic or positively basic properties for enhancing the dissolution - decomposition of base-acid structures present in the carbonaceous solid feed.

Materials and Morphology Study for Templated Hydrogen Solidification

DOE PAGES

Shin, Swanee J.; Kozioziemski, Bernard J.

2017-11-29

In this work, we performed a series of experiments to elucidate the characteristics of a good template for solid hydrogen nucleation. Zinc stands out among several materials with comparable size and shape. Nucleation could be observed to occur on top of sharp features, such as grain boundaries and cracks, but our attempts proved unsuccessful to fabricate or replicate such features. The variations of the supercooling (ΔT) values measured for comparable samples and the dependence of ΔT on the cell temperature cycling revealed that templated nucleation of solid hydrogen is a very delicate process.

Nuclear conversion theory: molecular hydrogen in non-magnetic insulators

NASA Astrophysics Data System (ADS)

Ilisca, Ernest; Ghiglieno, Filippo

2016-09-01

The hydrogen conversion patterns on non-magnetic solids sensitively depend upon the degree of singlet/triplet mixing in the intermediates of the catalytic reaction. Three main `symmetry-breaking' interactions are brought together. In a typical channel, the electron spin-orbit (SO) couplings introduce some magnetic excitations in the non-magnetic solid ground state. The electron spin is exchanged with a molecular one by the electric molecule-solid electron repulsion, mixing the bonding and antibonding states and affecting the molecule rotation. Finally, the magnetic hyperfine contact transfers the electron spin angular momentum to the nuclei. Two families of channels are considered and a simple criterion based on the SO coupling strength is proposed to select the most efficient one. The denoted `electronic' conversion path involves an emission of excitons that propagate and disintegrate in the bulk. In the other denoted `nuclear', the excited electron states are transients of a loop, and the electron system returns to its fundamental ground state. The described model enlarges previous studies by extending the electron basis to charge-transfer states and `continui' of band states, and focuses on the broadening of the antibonding molecular excited state by the solid conduction band that provides efficient tunnelling paths for the hydrogen conversion. After working out the general conversion algebra, the conversion rates of hydrogen on insulating and semiconductor solids are related to a few molecule-solid parameters (gap width, ionization and affinity potentials) and compared with experimental measures.

Nuclear conversion theory: molecular hydrogen in non-magnetic insulators

PubMed Central

Ghiglieno, Filippo

2016-01-01

The hydrogen conversion patterns on non-magnetic solids sensitively depend upon the degree of singlet/triplet mixing in the intermediates of the catalytic reaction. Three main ‘symmetry-breaking’ interactions are brought together. In a typical channel, the electron spin–orbit (SO) couplings introduce some magnetic excitations in the non-magnetic solid ground state. The electron spin is exchanged with a molecular one by the electric molecule–solid electron repulsion, mixing the bonding and antibonding states and affecting the molecule rotation. Finally, the magnetic hyperfine contact transfers the electron spin angular momentum to the nuclei. Two families of channels are considered and a simple criterion based on the SO coupling strength is proposed to select the most efficient one. The denoted ‘electronic’ conversion path involves an emission of excitons that propagate and disintegrate in the bulk. In the other denoted ‘nuclear’, the excited electron states are transients of a loop, and the electron system returns to its fundamental ground state. The described model enlarges previous studies by extending the electron basis to charge-transfer states and ‘continui’ of band states, and focuses on the broadening of the antibonding molecular excited state by the solid conduction band that provides efficient tunnelling paths for the hydrogen conversion. After working out the general conversion algebra, the conversion rates of hydrogen on insulating and semiconductor solids are related to a few molecule–solid parameters (gap width, ionization and affinity potentials) and compared with experimental measures. PMID:27703681

Effect of Hydrogen Charging on the Stress Corrosion Behavior of 2205 Duplex Stainless Steel Under 3.5 wt.% NaCl Thin Electrolyte Layer

NASA Astrophysics Data System (ADS)

Zhao, Tianliang; Liu, Zhiyong; Hu, Shanshan; Du, Cuiwei; Li, Xiaogang

2017-05-01

The effect of hydrogen charging on the stress corrosion cracking (SCC) behavior of 2205 duplex stainless steel (DSS) under 3.5 wt.% NaCl thin electrolyte layer was investigated on precharged samples through hydrogen determination, electrochemical measurement, and slow strain rate tensile test. Results show that hydrogen charging weakens the passive film without inducing any obvious trace of localized anodic dissolution. Therefore, hydrogen charging increases the SCC susceptibility of 2205 DSS mainly through mechanism of hydrogen embrittlement rather than mechanism of localized anodic dissolution. 2205 DSS shows a more susceptibility to hydrogen under the TEL when hydrogen charging current density (HCCD) is between 20 and 50 mA cm-2. The increasing trend is remarkable when hydrogen charging current density increases from 20 to 50 mA cm-2 and fades after 50 mA cm-2.

Pd/V.sub.2O.sub.5 device for colorimetric H.sub.2 detection

DOEpatents

Liu, Ping [San Diego, CA; Tracy, C Edwin [Golden, CO; Pitts, J Roland [Lakewood, CO; Smith, II, R. Davis; Lee, Se-Hee [Lakewood, CO

2008-09-02

A sensor structure for chemochromic optical detection of hydrogen gas over a wide response range, that exhibits stability during repeated coloring/bleaching cycles upon exposure and removal of hydrogen gas, comprising: a glass substrate (20); a vanadium oxide layer (21) coated on the glass substrate; and a palladium layer (22) coated on the vanadium oxide layer.

Composition design for Laves phase-related body-centered cubic-V solid solution alloys with large hydrogen storage capacities.

PubMed

Wang, H B; Wang, Q; Dong, C; Yuan, L; Xu, F; Sun, L X

2008-03-19

This paper analyzes the characteristics of alloy compositions with large hydrogen storage capacities in Laves phase-related body-centered cubic (bcc) solid solution alloy systems using the cluster line approach. Since a dense-packed icosahedral cluster A(6)B(7) characterizes the local structure of AB(2) Laves phases, in an A-B-C ternary system, such as Ti-Cr (Mn, Fe)-V, where A-B forms AB(2) Laves phases while A-C and B-C tend to form solid solutions, a cluster line A(6)B(7)-C is constructed by linking A(6)B(7) to C. The alloy compositions with large hydrogen storage capacities are generally located near this line and are approximately expressed with the cluster-plus-glue-atom model. The cluster line alloys (Ti(6)Cr(7))(100-x)V(x) (x = 2.5-70 at.%) exhibit different structures and hence different hydrogen storage capacities with increasing V content. The alloys (Ti(6)Cr(7))(95)V(5) and Ti(30)Cr(40)V(30) with bcc solid solution structure satisfy the cluster-plus-glue-atom model.

Surface-initiated phase transition in solid hydrogen under the high-pressure compression

NASA Astrophysics Data System (ADS)

Lei, Haile; Lin, Wei; Wang, Kai; Li, Xibo

2018-03-01

The large-scale molecular dynamics simulations have been performed to understand the microscopic mechanism governing the phase transition of solid hydrogen under the high-pressure compression. These results demonstrate that the face-centered-cubic-to-hexagonal close-packed phase transition is initiated first at the surfaces at a much lower pressure than in the volume and then extends gradually from the surface to volume in the solid hydrogen. The infrared spectra from the surface are revealed to exhibit a different pressure-dependent feature from those of the volume during the high-pressure compression. It is thus deduced that the weakening intramolecular H-H bonds are always accompanied by hardening surface phonons through strengthening the intermolecular H2-H2 coupling at the surfaces with respect to the counterparts in the volume at high pressures. This is just opposite to the conventional atomic crystals, in which the surface phonons are softening. The high-pressure compression has further been predicted to force the atoms or molecules to spray out of surface to degrade the pressure. These results provide a glimpse of structural properties of solid hydrogen at the early stage during the high-pressure compression.

Enhancing the stability of copper chromite catalysts for the selective hydrogenation of furfural using ALD overcoating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hongbo; Lei, Yu; Kropf, A. Jeremy

2014-08-01

The stability of a gas-phase furfural hydrogenation catalyst (CuCr2O4 center dot CuO) was enhanced by depositing a thin Al2O3 layer using atomic layer deposition (ALD). Based on temperature-programed reduction (TPR) measurements, the reduction temperature of Cu was raised significantly, and the activation energy for furfural reduction was decreased following the ALD treatment. Thinner ALD layers yielded higher furfural hydrogenation activities. X-ray absorption fine structure (XAFS) spectroscopy studies indicated that Cu1+/Cu-0 are the active species for furfural reduction.

A Novel Hybrid Axial-Radial Atmospheric Plasma Spraying Technique for the Fabrication of Solid Oxide Fuel Cell Anodes Containing Cu, Co, Ni, and Samaria-Doped Ceria

NASA Astrophysics Data System (ADS)

Cuglietta, Mark; Kuhn, Joel; Kesler, Olivera

2013-06-01

Composite coatings containing Cu, Co, Ni, and samaria-doped ceria (SDC) have been fabricated using a novel hybrid atmospheric plasma spraying technique, in which a multi-component aqueous suspension of CuO, Co3O4, and NiO was injected axially simultaneously with SDC injected radially in a dry powder form. Coatings were characterized for their microstructure, permeability, porosity, and composition over a range of plasma spray conditions. Deposition efficiency of the metal oxides and SDC was also estimated. Depending on the conditions, coatings displayed either layering or high levels of mixing between the SDC and metal phases. The deposition efficiencies of both feedstock types were strongly dependent on the nozzle diameter. Plasma-sprayed metal-supported solid oxide fuel cells utilizing anodes fabricated with this technique demonstrated power densities at 0.7 V as high as 366 and 113 mW/cm2 in humidified hydrogen and methane, respectively, at 800 °C.

Thermal stress analysis of sulfur deactivated solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Zeng, Shumao; Parbey, Joseph; Yu, Guangsen; Xu, Min; Li, Tingshuai; Andersson, Martin

2018-03-01

Hydrogen sulfide in fuels can deactivate catalyst for solid oxide fuel cells, which has become one of the most critical challenges to stability. The reactions between sulfur and catalyst will cause phase changes, leading to increase in cell polarization and mechanical mismatch. A three-dimensional computational fluid dynamics (CFD) approach based on the finite element method (FEM) is thus used to investigate the polarization, temperature and thermal stress in a sulfur deactivated SOFC by coupling equations for gas-phase species, heat, momentum, ion and electron transport. The results indicate that sulfur in fuels can strongly affect the cell polarization and thermal stresses, which shows a sharp decrease in the vicinity of electrolyte when 10% nickel in the functional layer is poisoned, but they remain almost unchanged even when the poisoned Ni content was increased to 90%. This investigation is helpful to deeply understand the sulfur poisoning effects and also benefit the material design and optimization of electrode structure to enhance cell performance and lifetimes in various hydrocarbon fuels containing impurities.

Critical evaluation of dipolar, acid-base and charge interactions I. Electron displacement within and between molecules, liquids and semiconductors.

PubMed

Rosenholm, Jarl B

2017-09-01

Specific dipolar, acid-base and charge interactions involve electron displacements. For atoms, single bonds and molecules electron displacement is characterized by electronic potential, absolute hardness, electronegativity and electron gap. In addition, dissociation, bonding, atomization, formation, ionization, affinity and lattice enthalpies are required to quantify the electron displacement in solids. Semiconductors are characterized by valence and conduction band energies, electron gaps and average Fermi energies which in turn determine Galvani potentials of the bulk, space charge layer and surface states. Electron displacement due to interaction between (probe) molecules, liquids and solids are characterized by parameters such as Hamaker constant, solubility parameter, exchange energy density, surface tension, work of adhesion and immersion. They are determined from permittivity, refractive index, enthalpy of vaporization, molar volume, surface pressure and contact angle. Moreover, acidic and basic probes may form adducts which are adsorbed on target substrates in order to establish an indirect measure of polarity, acidity, basicity or hydrogen bonding. Acidic acceptor numbers (AN), basic donor numbers (DN), acidic and basic "electrostatic" (E) and "covalent" (C) parameters determined by enthalpy of adduct formation are considered as general acid-base scales. However, the formal grounds for assignments as dispersive, Lifshitz-van der Waals, polar, acid, base and hydrogen bond interactions are inconsistent. Although correlations are found no of the parameters are mutually fully compatible and moreover the enthalpies of acid-base interaction do not correspond to free energies. In this review the foundations of different acid-base parameters relating to electron displacement within and between (probe) molecules, liquids and (semiconducting) solids are thoroughly investigated and their mutual relationships are evaluated. Copyright © 2017 Elsevier B.V. All rights reserved.

Binder Jetting: A Novel Solid Oxide Fuel-Cell Fabrication Process and Evaluation

NASA Astrophysics Data System (ADS)

Manogharan, Guha; Kioko, Meshack; Linkous, Clovis

2015-03-01

With an ever-growing concern to find a more efficient and less polluting means of producing electricity, fuel cells have constantly been of great interest. Fuel cells electrochemically convert chemical energy directly into electricity and heat without resorting to combustion/mechanical cycling. This article studies the solid oxide fuel cell (SOFC), which is a high-temperature (100°C to 1000°C) ceramic cell made from all solid-state components and can operate under a wide range of fuel sources such as hydrogen, methanol, gasoline, diesel, and gasified coal. Traditionally, SOFCs are fabricated using processes such as tape casting, calendaring, extrusion, and warm pressing for substrate support, followed by screen printing, slurry coating, spray techniques, vapor deposition, and sputter techniques, which have limited control in substrate microstructure. In this article, the feasibility of engineering the porosity and configuration of an SOFC via an additive manufacturing (AM) method known as binder jet printing was explored. The anode, cathode and oxygen ion-conducting electrolyte layers were fabricated through AM sequentially as a complete fuel cell unit. The cell performance was measured in two modes: (I) as an electrolytic oxygen pump and (II) as a galvanic electricity generator using hydrogen gas as the fuel. An analysis on influence of porosity was performed through SEM studies and permeability testing. An additional study on fuel cell material composition was conducted to verify the effects of binder jetting through SEM-EDS. Electrical discharge of the AM fabricated SOFC and nonlinearity of permeability tests show that, with additional work, the porosity of the cell can be modified for optimal performance at operating flow and temperature conditions.

Influence of deposition rate on the structural properties of plasma-enhanced CVD epitaxial silicon.

PubMed

Chen, Wanghua; Cariou, Romain; Hamon, Gwenaëlle; Léal, Ronan; Maurice, Jean-Luc; Cabarrocas, Pere Roca I

2017-03-06

Solar cells based on epitaxial silicon layers as the absorber attract increasing attention because of the potential cost reduction. In this work, we studied the influence of the deposition rate on the structural properties of epitaxial silicon layers produced by plasma-enhanced chemical vapor deposition (epi-PECVD) using silane as a precursor and hydrogen as a carrier gas. We found that the crystalline quality of epi-PECVD layers depends on their thickness and deposition rate. Moreover, increasing the deposition rate may lead to epitaxy breakdown. In that case, we observe the formation of embedded amorphous silicon cones in the epi-PECVD layer. To explain this phenomenon, we develop a model based on the coupling of hydrogen and built-in strain. By optimizing the deposition conditions to avoid epitaxy breakdown, including substrate temperatures and plasma potential, we have been able to synthesize epi-PECVD layers up to a deposition rate of 8.3 Å/s. In such case, we found that the incorporation of hydrogen in the hydrogenated crystalline silicon can reach 4 at. % at a substrate temperature of 350 °C.

Influence of deposition rate on the structural properties of plasma-enhanced CVD epitaxial silicon

PubMed Central

Chen, Wanghua; Cariou, Romain; Hamon, Gwenaëlle; Léal, Ronan; Maurice, Jean-Luc; Cabarrocas, Pere Roca i

2017-01-01

Solar cells based on epitaxial silicon layers as the absorber attract increasing attention because of the potential cost reduction. In this work, we studied the influence of the deposition rate on the structural properties of epitaxial silicon layers produced by plasma-enhanced chemical vapor deposition (epi-PECVD) using silane as a precursor and hydrogen as a carrier gas. We found that the crystalline quality of epi-PECVD layers depends on their thickness and deposition rate. Moreover, increasing the deposition rate may lead to epitaxy breakdown. In that case, we observe the formation of embedded amorphous silicon cones in the epi-PECVD layer. To explain this phenomenon, we develop a model based on the coupling of hydrogen and built-in strain. By optimizing the deposition conditions to avoid epitaxy breakdown, including substrate temperatures and plasma potential, we have been able to synthesize epi-PECVD layers up to a deposition rate of 8.3 Å/s. In such case, we found that the incorporation of hydrogen in the hydrogenated crystalline silicon can reach 4 at. % at a substrate temperature of 350 °C. PMID:28262840

Separation membrane development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, M.W.

1998-08-01

A ceramic membrane has been developed to separate hydrogen from other gases. The method used is a sol-gel process. A thin layer of dense ceramic material is coated on a coarse ceramic filter substrate. The pore size distribution in the thin layer is controlled by a densification of the coating materials by heat treatment. The membrane has been tested by permeation measurement of the hydrogen and other gases. Selectivity of the membrane has been achieved to separate hydrogen from carbon monoxide. The permeation rate of hydrogen through the ceramic membrane was about 20 times larger than Pd-Ag membrane.

Decomposition of poly(amide-imide) film enameled on solid copper wire using atmospheric pressure non-equilibrium plasma.

PubMed

Sugiyama, Kazuo; Suzuki, Katsunori; Kuwasima, Shusuke; Aoki, Yosuke; Yajima, Tatsuhiko

2009-01-01

The decomposition of a poly(amide-imide) thin film coated on a solid copper wire was attempted using atmospheric pressure non-equilibrium plasma. The plasma was produced by applying microwave power to an electrically conductive material in a gas mixture of argon, oxygen, and hydrogen. The poly(amide-imide) thin film was easily decomposed by argon-oxygen mixed gas plasma and an oxidized copper surface was obtained. The reduction of the oxidized surface with argon-hydrogen mixed gas plasma rapidly yielded a metallic copper surface. A continuous plasma heat-treatment process using a combination of both the argon-oxygen plasma and argon-hydrogen plasma was found to be suitable for the decomposition of the poly(amide-imide) thin film coated on the solid copper wire.

Liquid–solid phase transition of hydrogen and deuterium in silica aerogel

DOE PAGES

Van Cleve, E.; Worsley, M. A.; Kucheyev, S. O.

2014-10-30

Behavior of hydrogen isotopes confined in disordered low-density nanoporous solids remains essentially unknown. Here, we use relaxation calorimetry to study freezing and melting of H 2 and D 2 in an ~85%-porous base-catalyzed silica aerogel. In this work, we find that liquid–solid transition temperatures of both isotopes inside the aerogel are depressed. The phase transition takes place over a wide temperature range of ~4 K and non-trivially depends on the liquid filling fraction, reflecting the broad pore size distribution in the aerogel. Undercooling is observed for both H 2 and D 2 confined inside the aerogel monolith. Lastly, results formore » H 2 and D 2 are extrapolated to tritium-containing hydrogens with the quantum law of corresponding states.« less

Amyloid Hydrogen Bonding Polymorphism Evaluated by (15)N{(17)O}REAPDOR Solid-State NMR and Ultra-High Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

PubMed

Wei, Juan; Antzutkin, Oleg N; Filippov, Andrei V; Iuga, Dinu; Lam, Pui Yiu; Barrow, Mark P; Dupree, Ray; Brown, Steven P; O'Connor, Peter B

2016-04-12

A combined approach, using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and solid-state NMR (Nuclear Magnetic Resonance), shows a high degree of polymorphism exhibited by Aβ species in forming hydrogen-bonded networks. Two Alzheimer's Aβ peptides, Ac-Aβ(16-22)-NH2 and Aβ(11-25), selectively labeled with (17)O and (15)N at specific amino acid residues were investigated. The total amount of peptides labeled with (17)O as measured by FTICR-MS enabled the interpretation of dephasing observed in (15)N{(17)O}REAPDOR solid-state NMR experiments. Specifically, about one-third of the Aβ peptides were found to be involved in the formation of a specific >C═(17)O···H-(15)N hydrogen bond with their neighbor peptide molecules, and we hypothesize that the rest of the molecules undergo ± n off-registry shifts in their hydrogen bonding networks.

Cardboard proportions and total solids contents as driving factors in dry co-fermentation of food waste.

PubMed

Capson-Tojo, Gabriel; Trably, Eric; Rouez, Maxime; Crest, Marion; Bernet, Nicolas; Steyer, Jean-Philippe; Delgenès, Jean-Philippe; Escudié, Renaud

2018-01-01

This study evaluated the influence of the co-substrate proportions (0-60% of cardboard in dry basis) and the initial total solid contents (20-40%) on the batch fermentation performance. Maximum hydrogen yields were obtained when mono-fermenting food waste at high solids contents (89mlH 2 ·gVS -1 ). The hydrogen yields were lower when increasing the proportions of cardboard. The lower hydrogen yields at higher proportions of cardboard were translated into higher yields of caproic acid (up to 70.1gCOD·kgCOD bio -1 ), produced by consumption of acetic acid and hydrogen. The highest substrate conversions were achieved at low proportions of cardboard, indicating a stabilization effect due to higher buffering capacities in co-fermentation. Clostridiales were predominant in all operational conditions. This study opens up new possibilities for using the cardboard proportions for controlling the production of high added-value products in dry co-fermentation of food waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mechanochemical activation and synthesis of nanomaterials for hydrogen storage and conversion in electrochemical power sources.

PubMed

Wronski, Zbigniew S; Varin, Robert A; Czujko, Tom

2009-07-01

In this study we discuss a process of mechanical activation employed in place of chemical or thermal activation to improve the mobility and reactivity of hydrogen atoms and ions in nanomaterials for energy applications: rechargeable batteries and hydrogen storage for fuel cell systems. Two materials are discussed. Both are used or intended for use in power sources. One is nickel hydroxide, Ni(OH)2, which converts to oxyhydroxide in the positive Ni electrode of rechargeable metal hydride batteries. The other is a complex hydride, Mg(AIH4)2, intended for use in reversible, solid-state hydrogen storage for fuel cells. The feature shared by these unlikely materials (hydroxide and hydride) is a sheet-like hexagonal crystal structure. The mechanical activation was conducted in high-energy ball mills. We discuss and demonstrate that the mechanical excitation of atoms and ions imparted on these powders stems from the same class of phenomena. These are (i) proliferation of structural defects, in particular stacking faults in a sheet-like structure of hexagonal crystals, and (ii) possible fragmentation of a faulted structure into a mosaic of layered nanocrystals. The hydrogen atoms bonded in such nanocrystals may be inserted and abstracted more easily from OH- hydroxyl group in Ni(OH)2 and AlH4- hydride complex in Mg(AlH4)2 during hydrogen charge and discharge reactions. However, the effects of mechanical excitation imparted on these powders are different. While the Ni(OH)2 powder is greatly activated for cycling in batteries, the Mg(AlH4)2 complex hydride phase is greatly destabilized for use in reversible hydrogen storage. Such a "synchronic" view of the structure-property relationship in respect to materials involved in hydrogen energy storage and conversion is supported in experiments employing X-ray diffraction (XRD), differential scanning calorimetry (DSC) and direct imaging of the structure with a high-resolution transmission-electron microscope (HREM), as well as in property characterization.

Simple Electrolyzer Model Development for High-Temperature Electrolysis System Analysis Using Solid Oxide Electrolysis Cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

JaeHwa Koh; DuckJoo Yoon; Chang H. Oh

2010-07-01

An electrolyzer model for the analysis of a hydrogen-production system using a solid oxide electrolysis cell (SOEC) has been developed, and the effects for principal parameters have been estimated by sensitivity studies based on the developed model. The main parameters considered are current density, area specific resistance, temperature, pressure, and molar fraction and flow rates in the inlet and outlet. Finally, a simple model for a high-temperature hydrogen-production system using the solid oxide electrolysis cell integrated with very high temperature reactors is estimated.

First-principles study of the solid solution of hydrogen in lanthanum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoellhammer, Gunther; Herzig, Peter; Wolf, Walter

2011-09-01

Results from first-principles investigations of the energetical, structural, electronic, and vibrational properties of model structures probing the metal-rich region of the lanthanum-hydrogen system, i.e., the region of the solid solution of hydrogen in lanthanum, are presented. We have studied the site preference and the ordering tendency of hydrogen atoms interstitially bonded in close-packed lanthanum. Spatially separated hydrogen atoms have turned out to exhibit an energetical preference for the occupation of octahedral interstitial sites at low temperature. Indications for a reversal of the site preference in favor of the occupation of tetrahedral interstitial sites at elevated temperature have been found. Linearmore » arrangements consisting of pairs of octahedrally and/or tetrahedrally coordinated hydrogen atoms collinearly bonded to a central lanthanum atom have turned out to be energetically favorable structure elements. Further stabilization is achieved if such hydrogen pairs are in turn linked together so that extended chains of La-H bonds are formed. Pair formation and chain linking counteract the energetical preference for octahedral coordination observed for separated hydrogen atoms.« less

Engineering New Layered Solids from Exfoliated Inorganics: a Periodically Alternating Hydrotalcite – Montmorillonite Layered Hybrid

PubMed Central

Chalasani, Rajesh; Gupta, Amit; Vasudevan, Sukumaran

2013-01-01

Two-dimensional (2D) nanosheets obtained by exfoliating inorganic layered crystals have emerged as a new class of materials with unique attributes. One of the critical challenges is to develop robust and versatile methods for creating new nanostructures from these 2D-nanosheets. Here we report the delamination of layered materials that belonging to two different classes - the cationic clay, montmorillonite, and the anionic clay, hydrotalcite - by intercalation of appropriate ionic surfactants followed by dispersion in a non-polar solvent. The solids are delaminated to single layers of atomic thickness with the ionic surfactants remaining tethered to the inorganic and consequently the nanosheets are electrically neutral. We then show that when dispersions of the two solids are mixed the exfoliated sheets self-assemble as a new layered solid with periodically alternating hydrotalcite and montmorillonite layers. The procedure outlined here is easily extended to other layered solids for creating new superstructures from 2D-nanosheets by self-assembly. PMID:24336682

Solid-phase molecular recognition of cytosine based on proton-transfer reaction. Part II. supramolecular architecture in the cocrystals of cytosine and its 5-Fluoroderivative with 5-Nitrouracil

PubMed Central

2011-01-01

Background Cytosine is a biologically important compound owing to its natural occurrence as a component of nucleic acids. Cytosine plays a crucial role in DNA/RNA base pairing, through several hydrogen-bonding patterns, and controls the essential features of life as it is involved in genetic codon of 17 amino acids. The molecular recognition among cytosines, and the molecular heterosynthons of molecular salts fabricated through proton-transfer reactions, might be used to investigate the theoretical sites of cytosine-specific DNA-binding proteins and the design for molecular imprint. Results Reaction of cytosine (Cyt) and 5-fluorocytosine (5Fcyt) with 5-nitrouracil (Nit) in aqueous solution yielded two new products, which have been characterized by single-crystal X-ray diffraction. The products include a dihydrated molecular salt (CytNit) having both ionic and neutral hydrogen-bonded species, and a dihydrated cocrystal of neutral species (5FcytNit). In CytNit a protonated and an unprotonated cytosine form a triply hydrogen-bonded aggregate in a self-recognition ion-pair complex, and this dimer is then hydrogen bonded to one neutral and one anionic 5-nitrouracil molecule. In 5FcytNit the two neutral nucleobase derivatives are hydrogen bonded in pairs. In both structures conventional N-H...O, O-H...O, N-H+...N and N-H...N- intermolecular interactions are most significant in the structural assembly. Conclusion The supramolecular structure of the molecular adducts formed by cytosine and 5-fluorocytosine with 5-nitrouracil, CytNit and 5FcytNit, respectively, have been investigated in detail. CytNit and 5FcytNit exhibit widely differing hydrogen-bonding patterns, though both possess layered structures. The crystal structures of CytNit (Dpka = -0.7, molecular salt) and 5FcytNit (Dpka = -2.0, cocrystal) confirm that, at the present level of knowledge about the nature of proton-transfer process, there is not a strict correlation between the Dpka values and the proton transfer, in that the acid/base pka strength is not a definite guide to predict the location of H atoms in the solid state. Eventually, the absence in 5FcytNit of hydrogen bonds involving fluorine is in agreement with findings that covalently bound fluorine hardly ever acts as acceptor for available Brønsted acidic sites in the presence of competing heteroatom acceptors. PMID:21888640

Trapped-mode-induced Fano resonance and acoustical transparency in a one-dimensional solid-fluid phononic crystal

NASA Astrophysics Data System (ADS)

Quotane, Ilyasse; El Boudouti, El Houssaine; Djafari-Rouhani, Bahram

2018-01-01

We investigate theoretically and numerically the possibility of existence of Fano and acoustic-induced transparency (AIT) resonances in a simple though realistic one-dimensional acoustic structure made of solid-fluid layers inserted between two fluids. These resonances are obtained by combining appropriately the zeros of transmission (antiresonance) induced by the solid layers and the local resonances induced by the solid or combined solid-fluid layers with surface free boundary conditions. In particular, we show the possibility of trapped modes, also called bound states in continuum, which have recently found a high renewal interest. These modes appear as resonances with zero width in the transmission spectra as well as in the density of states (DOS). We consider three different structures: (i) a single solid layer inserted between two fluids. This simple structure shows the possibility of existence of trapped modes, which are discrete modes of the solid layer that lie in the continuum modes of the surrounding fluids. We give explicit analytical expressions of the dispersion relation of these eigenmodes of the solid layer which are found independent of the nature of the surrounding fluids. By slightly detuning the angle of incidence from that associated to the trapped mode, we get a well-defined Fano resonance characterized by an asymmetric Fano profile in the transmission spectra. (ii) The second structure consists of a solid-fluid-solid triple layer embedded between two fluids. This structure is found more appropriate to show both Fano and acoustic-induced transparency resonances. We provide detailed analytical expressions for the transmission and reflection coefficients that enable us to deduce a closed-form expression of the dispersion relation giving the trapped modes. Two situations can be distinguished in the triple-layer system: in the case of a symmetric structure (i.e., the same solid layers) we show, by detuning the incidence angle θ , the possibility of existence of Fano resonances that can be fitted following a Fano-type expression. The variation of the Fano parameter that describes the asymmetry of such resonances as well as their width versus θ is studied in detail. In the case of an asymmetric structure (i.e., different solid layers), we show the existence of an incidence angle that enables to squeeze a resonance between two transmission zeros induced by the two solid layers. This resonance behaves like an AIT resonance, its position and width depend on the nature of the fluid and solid layers as well as on the difference between the thicknesses of the solid layers. (iii) In the case of a periodic structure (phononic crystal), we show that trapped modes and Fano resonances give rise, respectively, to dispersionless flat bands with zero group velocity and nearly flat bands with negative or positive group velocities. The analytical results presented here are obtained by means of the Green's function method which enables to deduce in closed form: dispersion curves, transmission and reflection coefficients, DOS, as well as the displacement fields. The proposed solid-fluid layered structures should have important applications for designing acoustic mirrors and acoustic filters as well as supersonic and subsonic materials.

Optical fingerprints of solid-liquid interfaces: a joint ATR-IR and first principles investigation

NASA Astrophysics Data System (ADS)

Yang, L.; Niu, F.; Tecklenburg, S.; Pander, M.; Nayak, S.; Erbe, A.; Wippermann, S.; Gygi, F.; Galli, G.

Despite the importance of understanding the structural and bonding properties of solid-liquid interfaces for a wide range of (photo-)electrochemical applications, there are presently no experimental techniques available to directly probe the microscopic structure of solid-liquid interfaces. To develop robust strategies to interpret experiments and validate theory, we carried out attenuated total internal reflection (ATR-IR) spectroscopy measurements and ab initio molecular dynamics (AIMD) simulations of the vibrational properties of interfaces between liquid water and well-controlled prototypical semiconductor substrates. We show the Ge(100)/H2O interface to feature a reversible potential-dependent surface phase transition between Ge-H and Ge-OH termination. The Si(100)/H2O interface is proposed as a model system for corrosion and oxidation processes. We performed AIMD calculations under finite electric fields, revealing different pathways for initial oxidation. These pathways are predicted to exhibit unique spectral signatures. A significant increase in surface specificity can be achieved utilizing an angle-dependent ATR-IR experiment, which allows to detect such signatures at the interfacial layer and consequently changes in the hydrogen bond network. Funding from DOE-BES Grant No. DE-SS0008939 and the Deutsche Forschungsgemeinschaft (RESOLV, EXC 1069) are gratefully acknowledged.

Calculated Properties of Fully Hydrogenated Single Layers of BN, BC2N, and Graphene: Graphane and Its BN-Containing Analogues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Averill, Frank; Morris, James R; Cooper, Valentino R

2009-01-01

Carbon is an attractive material for hydrogen adsorption, due to its light weight, variety of structures, and ability to both physisorb and chemisorb hydrogen. Recently, fully hydrogenated graphene layers ( graphane ) have been predicted to exist [J.O. Sofo et al., Phys. Rev. B 75, 15340 (2007)], and experimentally observed [D.C. Elias et al., Science 323, 610 (2009)]. In this work, we examine analogues of graphane, in particular BNH2 and BC2NH4. Unlike graphene, these materials have a band gap without hydrogenation. Our results indicate that the hydrogenation product of BN is metastable: the fully hydrogenated compound BNH2 is higher inmore » energy than hexagonal BN sheets plus H2 molecules, in sharp contrast with graphane. We find that BC2NH4 is energetically very close to hexagonal BC2N+2H2 molecules. Furthermore our examination of the relative binding strengths of rows of symmetry related hydrogen atoms on BC2NH4shows that this compound is marginally higher in energy than BC2NH2 plus an H2 molecule, with the hydrogen atoms in BC2NH2 absorbed on the carbon sites. These remaining hydrogen atoms are not as strongly bound as in graphane, indicating that the average hydrogen chemisorption energy is controllable by changing the carbon content in the B-C-N layer.« less

Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. [Polyetherimide, cellulose acetate and ethylcellulose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-01-01

The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with anmore » ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.« less

Preparation and characterization of azithromycin--Aerosil 200 solid dispersions with enhanced physical stability.

PubMed

Li, Xuechao; Peng, Huanhuan; Tian, Bin; Gou, Jingxin; Yao, Qing; Tao, Xiaoguang; He, Haibing; Zhang, Yu; Tang, Xing; Cai, Cuifang

2015-01-01

The main purpose of this study was to investigate the feasibility of azithromycin (AZI)--Aerosil 200 solid dispersions specifically with high stability under accelerated condition (40 °C/75% RH). Ball milling (BM) and hot-melt extrusion (HME) were used to prepare AZI solid dispersions. The physical properties of solid dispersions were evaluated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). For solid dispersions prepared with both methods, no crystalline of AZI was detected (except for AZI: Aerosil 200=75:25) by DSC or PXRD, indicating the amorphous state of AZI in solid dispersions. The FT-IR results demonstrated the loss of crystallization water and the formation of hydrogen bonds between Aerosil 200 and AZI during the preparation of solid dispersions. After 4 weeks storage under accelerated condition, the degree of crystallinity of AZI increased in solid dispersions prepared by BM, whereas for solid dispersions containing AZI, Aerosil 200 and glyceryl behenate (GB) prepared by HME, no crystalline of AZI was identified. This high stability can be attributed to the hydrophobic properties of GB and the presence of hydrogen bonds. Based on the above results, it is inferred the protection of hydrogen bonds between AZI and Aerosil 200 formed during preparation process effectively inhibited the recrystallization of AZI and improved the physical stability of amorphous AZI in the presence of Aerosil 200. Copyright © 2015 Elsevier B.V. All rights reserved.

On the solid phase crystallization of In{sub 2}O{sub 3}:H transparent conductive oxide films prepared by atomic layer deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macco, Bart; Verheijen, Marcel A.; Black, Lachlan E.

2016-08-28

Hydrogen-doped indium oxide (In{sub 2}O{sub 3}:H) has emerged as a highly transparent and conductive oxide, finding its application in a multitude of optoelectronic devices. Recently, we have reported on an atomic layer deposition (ALD) process to prepare high quality In{sub 2}O{sub 3}:H. This process consists of ALD of In{sub 2}O{sub 3}:H films at 100 °C, followed by a solid phase crystallization step at 150–200 °C. In this work, we report on a detailed electron microscopy study of this crystallization process which reveals new insights into the crucial aspects for achieving the large grain size and associated excellent properties of the material. Themore » key finding is that the best optoelectronic properties are obtained by preparing the films at the lowest possible temperature prior to post-deposition annealing. Electron microscopy imaging shows that such films are mostly amorphous, but feature a very low density of embedded crystallites. Upon post-deposition annealing, crystallization proceeds merely from isotropic crystal grain growth of these embedded crystallites rather than by the formation of additional crystallites. The relatively high hydrogen content of 4.2 at. % in these films is thought to cause the absence of additional nucleation, thereby rendering the final grain size and optoelectronic properties solely dependent on the density of embedded crystallites. The temperature-dependent grain growth rate has been determined, from which an activation energy of (1.39 ± 0.04) eV has been extracted. Finally, on the basis of the observed crystallization mechanism, a simple model to fully describe the crystallization process has been developed. This model has been validated with a numerical implementation thereof, which accurately predicts the observed temperature-dependent crystallization behaviour.« less

Layered solid sorbents for carbon dioxide capture

DOEpatents

Li, Bingyun; Jiang, Bingbing; Gray, McMahan L; Fauth, Daniel J; Pennline, Henry W; Richards, George A

2013-02-25

A solid sorbent for the capture and the transport of carbon dioxide gas is provided having at least one first layer of a positively charged material that is polyethylenimine or poly(allylamine hydrochloride), that captures at least a portion of the gas, and at least one second layer of a negatively charged material that is polystyrenesulfonate or poly(acryclic acid), that transports the gas, wherein the second layer of material is in juxtaposition to, attached to, or crosslinked with the first layer for forming at least one bilayer, and a solid substrate support having a porous surface, wherein one or more of the bilayers is/are deposited on the surface of and/or within the solid substrate. A method of preparing and using the solid sorbent is provided.

Layered solid sorbents for carbon dioxide capture

DOEpatents

Li, Bingyun; Jiang, Bingbing; Gray, McMahan L; Fauth, Daniel J; Pennline, Henry W; Richards, George A

2014-11-18

A solid sorbent for the capture and the transport of carbon dioxide gas is provided having at least one first layer of a positively charged material that is polyethylenimine or poly(allylamine hydrochloride), that captures at least a portion of the gas, and at least one second layer of a negatively charged material that is polystyrenesulfonate or poly(acryclic acid), that transports the gas, wherein the second layer of material is in juxtaposition to, attached to, or crosslinked with the first layer for forming at least one bilayer, and a solid substrate support having a porous surface, wherein one or more of the bilayers is/are deposited on the surface of and/or within the solid substrate. A method of preparing and using the solid sorbent is provided.

Silicon based multilayer photoelectrodes for photoelectrolysis of water to produce hydrogen from the sun

NASA Astrophysics Data System (ADS)

Faruque, Faisal

The main objective of this work is to study different materials for the direct photosynthesis of hydrogen from water. A variety of photocatalysts such as titanium dioxide, titanium oxy-nitride, silicon carbide, and gallium nitride are being investigated by others for the clean production of hydrogen for fuel cells and hydrogen economy. Our approach was to deposit suitable metallic regions on photocatalyst nanoparticles to direct the efficient synthesis of hydrogen to a particular site for convenient collection. We studied different electrode metals such as gold, platinum, titanium, palladium, and tungsten. We also studied different solar cell materials such as silicon (p- and n-types), silicon carbide and titanium dioxide semiconductors in order to efficiently generate electrons under illumination. We introduced a novel silicon-based multilayer photosynthesis device to take advantage of suitable properties of silicon and tungsten to efficiently produce hydrogen. The device consisted of a silicon (0.5mm) substrate, a deposited atomic layer of Al2O 3 (1nm), a doped polysilicon (0.1microm), and finally a tungsten nanoporous (5-10nm) layer acting as an interface electrode with water. The Al2O 3 layer was introduced to reduce leakage current and to prevent the spreading of the diffused p-n junction layer between the silicon and doped polysilicon layers. The surface of the photoelectrode was coated with nanotextured tungsten nanopores (TNP), which increased the surface area of the electrodes to the electrolyte, assisting in electron-hole mobility, and acting as a photocatalyst. The reported device exhibited a fill factor (%FF) of 27.22% and solar-to-hydrogen conversion efficiency of 0.03174%. This thesis describes the structures of the device, and offers a characterization and comparison between different photoelectrodes.

A new family of metal borohydride guanidinate complexes: Synthesis, structures and hydrogen-storage properties

NASA Astrophysics Data System (ADS)

Wu, Hui; Zhou, Xiuquan; Rodriguez, Efrain E.; Zhou, Wei; Udovic, Terrence J.; Yildirim, Taner; Rush, John J.

2016-10-01

We report on a new class of complex hydrides: borohydride guanidinate complexes (MBH4·nCN3H5, M=Li, Mg, and Ca). They can be prepared via facile solid-state synthesis routes. Their crystal structures were successfully determined using a combination of X-ray diffraction, first-principles calculations and neutron vibrational spectroscopy. Among these compounds, Mg(BH4)2·6CN3H5 is composed of large complex Mg[CN3H5]62+ cations and surrounding BH4- ions, while Ca(BH4)2·2CN3H5 possesses layers of corner-sharing Ca[BH4]4(CN3H5)2 octahedra. Our dehydrogenation results show that ≈10 wt% hydrogen can be released from MBH4·nCN3H5 (M=Li, Mg, and Ca) at moderate temperatures with minimal ammonia and diborane contamination thanks to the synergistic effect of C-N bonds from guanidine and hydridic H from borohydrides leading to a weakening of the N-H bonds, thus impeding ammonia gas liberation. Further tuning the dehydrogenation with different cation species indicates that Mg(BH4)2·nCN3H5 can exhibit the optimum properties with nearly thermally neutral dehydrogenation and very high purity hydrogen release.

Electron-stimulated reactions in nanoscale water films adsorbed on (alpha)-Al2O3(0001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrik, Nikolay G.; Kimmel, Gregory A.

2018-05-11

The radiation-induced decomposition and desorption of nanoscale amorphous solid water (D2O) films adsorbed on -Al2O3(0001) surface was studied at low temperature in ultrahigh vacuum using temperature programmed desorption (TPD) and electron stimulated desorption (ESD) with a mono-energetic, low energy electron source. ESD yields of molecular products ( D2, O2 and D¬2O) and the total sputtering yield increased with increasing D2O coverage up to ~15 water monolayers (i.e. ~15 1015 cm-2) to a coverage-independent level for thicker water films. Experiments with isotopically-layered water films (D2O and H2O) demonstrated that the highest water decomposition yields occurred at the interfaces of the nanoscalemore » water films with the alumina substrate and vacuum. However, the increased reactivity of the water/alumina interface is relatively small compared to the enhancements in the non-thermal reactions previously observed at the water/Pt(111) and water/TiO2(110) interfaces. We propose that the relatively low activity of Al2O3(0001) for the radiation-induced production of molecular hydrogen is associated with lower reactivity of this surface with hydrogen atoms, which are likely precursors for the molecular hydrogen.« less

Electron-stimulated reactions in nanoscale water films adsorbed on α-Al 2 O 3 (0001)

DOE PAGES

Petrik, Nikolay G.; Kimmel, Greg A.

2018-04-11

The radiation-induced decomposition and desorption of nanoscale amorphous solid water (D 2O) films adsorbed on an α-Al 2O 3(0001) surface was studied at low temperature in ultrahigh vacuum using temperature programmed desorption (TPD) and electron stimulated desorption (ESD) with a mono-energetic, low energy electron source. ESD yields of molecular products (D 2, O 2 and D 2O) and the total sputtering yield increased with increasing D 2O coverage up to ~15 water monolayers (i.e. ~15 x 10 15 cm -2) to a coverage-independent level for thicker water films. Experiments with isotopically-layered water films (D 2O and H 2O) demonstrated thatmore » the highest water decomposition yields occurred at the interfaces of the nanoscale water films with the alumina substrate and vacuum. However, the increased reactivity of the water/alumina interface is relatively small compared to the enhancements in the non-thermal reactions previously observed at the water/Pt(111) and water/TiO 2(110) interfaces. Here, we propose that the relatively low activity of Al 2O 3(0001) for the radiation-induced production of molecular hydrogen is associated with lower reactivity of this surface with hydrogen atoms, which are likely precursors for the formation of molecular hydrogen.« less

Continuous Steelmaking Directly from Ore

NASA Astrophysics Data System (ADS)

Warner, Noel A.

2014-12-01

In-line continuous processing of high-grade hematite ore (crushed ore or fines) with a pure hydrogen reductant is assessed. An appraisal is made of the rate controlling mechanisms involved in the reduction of a pure layer of molten wustite being transported by floating on a molten carrier iron carbon-free medium at temperatures just in excess of the iron melting point. Published research clearly indicates that under these conditions the kinetics are principally controlled by molecular gaseous diffusion. Thus, the rate is essentially not influenced by total gas pressure above 1 atmosphere. Accordingly, on safety grounds it is recommended that high pressure should not be used for hydrogen steelmaking in the future, but the operation should be conducted close to atmospheric pressure with low pressure steam encapsulation of the plant items involved. Using hydrogen as the reductant means that sub-surface nucleation of CO bubbles cannot disrupt continuous processing. The operation is then no different to processing a normal liquid phase. The off-gases from the reduction zone of a melt circulation loop are super-clean and only contaminated with iron vapor. Accordingly, the best available technology becomes available for energy conservation without risk of non-fusible solids deposition. The net result is that the energy requirements are expected to be superior to other potential processes.

Electron-stimulated reactions in nanoscale water films adsorbed on α-Al 2 O 3 (0001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrik, Nikolay G.; Kimmel, Greg A.

The radiation-induced decomposition and desorption of nanoscale amorphous solid water (D 2O) films adsorbed on an α-Al 2O 3(0001) surface was studied at low temperature in ultrahigh vacuum using temperature programmed desorption (TPD) and electron stimulated desorption (ESD) with a mono-energetic, low energy electron source. ESD yields of molecular products (D 2, O 2 and D 2O) and the total sputtering yield increased with increasing D 2O coverage up to ~15 water monolayers (i.e. ~15 x 10 15 cm -2) to a coverage-independent level for thicker water films. Experiments with isotopically-layered water films (D 2O and H 2O) demonstrated thatmore » the highest water decomposition yields occurred at the interfaces of the nanoscale water films with the alumina substrate and vacuum. However, the increased reactivity of the water/alumina interface is relatively small compared to the enhancements in the non-thermal reactions previously observed at the water/Pt(111) and water/TiO 2(110) interfaces. Here, we propose that the relatively low activity of Al 2O 3(0001) for the radiation-induced production of molecular hydrogen is associated with lower reactivity of this surface with hydrogen atoms, which are likely precursors for the formation of molecular hydrogen.« less

Solid-state structure of 1-(diaminomethylene)thiouron-1-ium propionate

NASA Astrophysics Data System (ADS)

Janczak, Jan

2017-10-01

The single crystals of 1-(diaminomethylene)thiouron-1-ium propionate suitable for the X-ray analysis were grown using a solution growth technique room temperature. The compound crystallises in the centrosymmetric C2/c space group of the monoclinic system. The conformation of the 1-(diaminomethylene)thiouron-1-ium cation is not strictly planar, but slightly twisted. Both planar arms of the cation are oppositely rotated by 2.1(1)° around the Csbnd N bonds involving the central N atom. The propionate(-) anion is also non-planar, the carboxylate group is turned by 4.3(1)° in relation to the planar carbon chain. The arrangement of oppositely charged components, i.e. 1-(diaminomethylene)thiouron-1-ium cations and propionate(-) anions in the crystal is mainly determined by ionic and Nsbnd H⋯O hydrogen bonding interactions forming two-dimensional network aligned to (100) plane. The neighbouring 2D layers interact via much weaker Nsbnd H⋯S hydrogen bonds forming three-dimensional hydrogen bonded network. Hirshfeld surface and the analysis of 2D fingerprint plots are illustrating both quantitatively and qualitatively interactions governing the supramolecular assemblies. The compound was also characterised by the FT-IR and Raman spectroscopy. The vibrational assignments have been supported by the isotopic frequency shift.

The evaluation of layered separators for nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Gahn, Randall F.

1991-01-01

The concept of using layered separators to achieve the required electrolyte retention and bubble pressure fo nickel-hydrogen cells was evaluated in a boilerplate cell test. Zircar cloth, polyethylene paper and polypropylene felt were combined with a layer of radiation-grafted polyethylene film to achieve the required properties. Three cells of each layered separator were built and tested by characterization cycling and by low earth orbit cycling for 5000 cycles at 80 percent DOD. Three cells containing asbestos separators were used as the reference.

Ferrocenylaniline based amide analogs of methoxybenzoic acids: Synthesis, structural characterization and butyrylcholinesterase (BChE) inhibition studies

NASA Astrophysics Data System (ADS)

Altaf, Ataf Ali; Kausar, Samia; Hamayun, Muhammad; Lal, Bhajan; Tahir, Muhammad Nawaz; Badshah, Amin

2017-10-01

Three new ferrocene based amides were synthesized with slight structural difference. The general formula of the amides is C5H5FeC5H4C6H4NHCOC6H4(OCH3). The synthesized compounds were characterized by instrumental techniques like elemental analysis, FTIR and NMR spectroscopy. Structure of the two compounds was also studied by single crystal X-rays diffraction analysis. Structural studies provide the evidence that pMeO (one of the synthesized compounds) is an example of amides having no intermolecular hydrogen bonding in solid structure. In the BChE inhibition assay, compound (oMeO) having strong intermolecular force in the solid structure is less active than the compound (pMeO) with weak intermolecular forces in the solid structure. The docking studies proved that hydrogen bonding between inhibitor and BChE enzyme is of more importance for the activity, rather than intermolecular hydrogen bonding in the solid structure of inhibitor.

Near-infrared analysis of hydrogen-bonding in glass- and rubber-state amorphous saccharide solids.

PubMed

Izutsu, Ken-ichi; Hiyama, Yukio; Yomota, Chikako; Kawanishi, Toru

2009-01-01

Near-infrared (NIR) spectroscopic analysis of noncrystalline polyols and saccharides (e.g., glycerol, sorbitol, maltitol, glucose, sucrose, maltose) was performed at different temperatures (30-80 degrees C) to elucidate the effect of glass transition on molecular interaction. Transmission NIR spectra (4,000-12,000 cm(-1)) of the liquids and cooled-melt amorphous solids showed broad absorption bands that indicate random configuration of molecules. Heating of the samples decreased an intermolecular hydrogen-bonding OH vibration band intensity (6,200-6,500 cm(-1)) with a concomitant increase in a free and intramolecular hydrogen-bonding OH group band (6,600-7,100 cm(-1)). Large reduction of the intermolecular hydrogen-bonding band intensity at temperatures above the glass transition (T(g)) of the individual solids should explain the higher molecular mobility and lower viscosity in the rubber state. Mixing of the polyols with a high T(g) saccharide (maltose) or an inorganic salt (sodium tetraborate) shifted both the glass transition and the inflection point of the hydrogen-bonding band intensity to higher temperatures. The implications of these results for pharmaceutical formulation design and process monitoring (PAT) are discussed.

Mg/Ti multilayers: Structural and hydrogen absorption properties

NASA Astrophysics Data System (ADS)

Baldi, A.; Pálsson, G. K.; Gonzalez-Silveira, M.; Schreuders, H.; Slaman, M.; Rector, J. H.; Krishnan, G.; Kooi, B. J.; Walker, G. S.; Fay, M. W.; Hjörvarsson, B.; Wijngaarden, R. J.; Dam, B.; Griessen, R.

2010-06-01

Mg-Ti alloys have uncommon optical and hydrogen absorbing properties, originating from a “spinodal-like” microstructure with a small degree of chemical short-range order in the atomic distribution. In the present study we artificially engineer short-range order by depositing Pd-capped Mg/Ti multilayers with different periodicities. Notwithstanding the large lattice mismatch between Mg and Ti, the as-deposited metallic multilayers show good structural coherence. On exposure to H2 gas a two-step hydrogenation process occurs with the Ti layers forming the hydride before Mg. From in situ measurements of the bilayer thickness Λ at different hydrogen pressures, we observe large out-of-plane expansions of Mg and Ti layers on hydrogenation, indicating strong plastic deformations in the films and a consequent shortening of the coherence length. On unloading at room temperature in air, hydrogen atoms remain trapped in the Ti layers due to kinetic constraints. Such loading/unloading sequence can be explained in terms of the different thermodynamic properties of hydrogen in Mg and Ti, as shown by diffusion calculations on a model multilayered systems. Absorption isotherms measured by hydrogenography can be interpreted as a result of the elastic clamping arising from strongly bonded Mg/Pd and broken Mg/Ti interfaces.

Slow positron studies of hydrogen activation/passivation on SiO2/Si(100) interfaces

NASA Astrophysics Data System (ADS)

Lynn, K. G.; Asoka-Kumar, P.

The hydrogen atoms are one of the most common impurity species found in semiconductor systems owing to its large diffusivity, and are easily incorporated either in a controlled process like in ion implantation or in an uncontrolled process like the one at the fabrication stage. Hydrogen can passivate dangling bonds and dislocations in these systems and hence can be used to enhance the electrical properties. In a SiO2/Si system, hydrogen can passivate electronic states at the interface and can alter the fixed or mobile charges in the oxide layer. Since hydrogen is present in almost all of the environments of SiO2/Si wafer fabrication, the activation energy of hydrogen atoms is of paramount importance to a proper understanding of SiO2/Si based devices and has not been measured on the technologically most important Si(100) face. There are no direct, nondestructive methods available to observe hydrogen injection into the oxide layer and subsequent diffusion. The positrons are used as a 'sensitive', nondestructive probe to observe hydrogen interaction in the oxide layer and the interface region. A new way is described of characterizing the changes in the density of the interface states under a low temperature annealing using positrons.

Apparatus and methods for storing and releasing hydrogen

DOEpatents

Heung, Leung K.

2001-01-01

A rechargeable device that stores and discharges hydrogen is described. The device stores hydrogen in a solid form and supplies hydrogen as a gas when needed. The solid storage medium may be metal hydride in a ground particle form that avoids the need for compaction or other treatment. Dividers partition a container into separate chambers, each provided with a matrix, formed from an appropriate material like a thermally-conductive aluminum foam, which forms a number of cells. For proper chamber size, the ratio of chamber length to container diameter should be between about 0.5 and 2. Metal hydride particles (or other hydrogen storage medium) may be placed within the cells, which help prevent excessive particle settling. The container is provided with a hydrogen transfer port through which hydrogen gas passes upon either discharging from or charging of the metal hydride particles. A filter may be placed within the port to allow hydrogen to flow but prevent particles from escaping. A heat transferring surface is formed by, for instance, a channel that is thermally coupled with the aluminum foam. Fluid flows through the channel to deliver or remove heat during the respective hydrogen discharging or charging processes.

Apparatus and methods for storing and releasing hydrogen

DOEpatents

Heung, Leung K.

2000-01-01

A rechargeable device that stores and discharges hydrogen is described. The device stores hydrogen in a solid form and supplies hydrogen as a gas when needed. The solid storage medium may be metal hydride in a ground particle form that avoids the need for compaction or other treatment. Dividers partition a container into separate chambers, each provided with a matrix, formed from an appropriate material like a thermally-conductive aluminum foam, which forms a number of cells. For proper chamber size, the ratio of chamber length to container diameter should be between about 0.5 and 2. Metal hydride particles (or other hydrogen storage medium) may be placed within the cells, which help prevent excessive particle settling. The container is provided with a hydrogen transfer port through which hydrogen gas passes upon either discharging from or charging of the metal hydride particles. A filter may be placed within the port to allow hydrogen to flow but prevent particles from escaping. A heat transferring surface is formed by, for instance, a channel that is thermally coupled with the aluminum foam. Fluid flows through the channel to deliver or remove heat during the respective hydrogen discharging or charging processes.

Air Force Phillips Laboratory Battery Program overview

NASA Technical Reports Server (NTRS)

House, Shaun

1992-01-01

Battery development and testing efforts at Phillips Laboratory fall into three main categories: nickel hydrogen, sodium sulfur, and solid state batteries. Nickel hydrogen work is broken down into a Low Earth Orbit (LEO) Life Test Program, a LEO Pulse Test Program, and a Hydrogen Embrittlement Investigation. Sodium sulfur work is broken down into a Geosynchronous Earth Orbit (GEO) Battery Flight Test and a Hot Launch Evaluation. Solid state polymer battery work consists of a GEO Battery Development Program, a Pulse Power Battery Small Business Innovation Research (SBIR), and an in-house evaluation of current generation laboratory cells. An overview of the program is presented.

Two polymorphs of safinamide, a selective and reversible inhibitor of monoamine oxidase B.

PubMed

Ravikumar, Krishnan; Sridhar, Balasubramanian

2010-06-01

Two polymorphs of safinamide {systematic name: (2S)-2-[4-(3-fluorobenzyloxy)benzylamino]propionamide}, C(17)H(19)FN(2)O(2), a potent selective and reversible monoamine oxidase B (MAO-B) inhibitor, are described. Both forms are orthorhombic and regarded as conformational polymorphs due to the differences in the orientation of the 3-fluorobenzyloxy and propanamide groups. Both structures pack with layers in the ac plane. In polymorph (I), the layers have discrete wide and narrow regions which are complementary when located next to adjacent layers. In polymorph (II), the layer has long flanges protruding from each side, which interdigitate when packed with the adjacent layers. N-H...O hydrogen bonds are present in both structures, whereas N-H...F hydrogen bonding is seen in polymorph (I), while N-H...N hydrogen bonding is seen in polymorph (II).

Cryogenic target system for hydrogen layering

DOE PAGES

Parham, T.; Kozioziemski, B.; Atkinson, D.; ...

2015-11-24

Here, a cryogenic target positioning system was designed and installed on the National Ignition Facility (NIF) target chamber. This instrument incorporates the ability to fill, form, and characterize the NIF targets with hydrogen isotopes needed for ignition experiments inside the NIF target bay then transport and position them in the target chamber. This effort brought to fruition years of research in growing and metrologizing high-quality hydrogen fuel layers and landed it in an especially demanding operations environment in the NIF facility. D-T (deuterium-tritium) layers for NIF ignition experiments have extremely tight specifications and must be grown in a very highlymore » constrained environment: a NIF ignition target inside a cryogenic target positioner inside the NIF target bay. Exquisite control of temperature, pressure, contaminant level, and thermal uniformity are necessary throughout seed formation and layer growth to create an essentially-groove-free single crystal layer.« less

Hydrogen speciation in hydrated layers on nuclear waste glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aines, R.D.; Weed, H.C.; Bates, J.K.

1987-01-15

The hydration of an outer layer on nuclear waste glasses is known to occur during leaching, but the actual speciation of hydrogen (as water or hydroxyl groups) in these layers has not been determined. As part of the Nevada Nuclear Waste Storage Investigations Project, we have used infrared spectroscopy to determine hydrogen speciations in three nuclear waste glass compositions (SRL-131 & 165, and PNL 76-68), which were leached at 90{sup 0}C (all glasses) or hydrated in a vapor-saturated atmosphere at 202{sup 0}C (SRL-131 only). Hydroxyl groups were found in the surface layers of all the glasses. Molecular water was foundmore » in the surface of SRL-131 and PNL 76-68 glasses that had been leached for several months in deionized water, and in the vapor-hydrated sample. The water/hydroxyl ratio increases with increasing reaction time; molecular water makes up most of the hydrogen in the thick reaction layers on vapor-phase hydrated glass while only hydroxyl occurs in the least reacted samples. Using the known molar absorptivities of water and hydroxyl in silica-rich glass the vapor-phase layer contained 4.8 moles/liter of molecular water, and 0.6 moles water in the form hydroxyl. A 15 {mu}m layer on SRL-131 glass formed by leaching at 90{sup 0}C contained a total of 4.9 moles/liter of water, 2/3 of which was as hydroxyl. The unreacted bulk glass contains about 0.018 moles/liter water, all as hydroxyl. The amount of hydrogen added to the SRL-131 glass was about 70% of the original Na + Li content, not the 300% that would result from alkali=hydronium ion interdiffusion. If all the hydrogen is then assumed to be added as the result of alkali-H{sup +} interdiffusion, the molecular water observed may have formed from condensation of the original hydroxyl groups.« less

High-rate/high-temperature capability of a single-layer zicar-separator nickel-hydrogen cell

NASA Technical Reports Server (NTRS)

Wheeler, James R.

1995-01-01

A 50 Ampere-hour nickel-hydrogen cell with a single-layer Zircar separator stack design was fully charged and then discharged at a 2C current rate to an end voltage of 1 volt. This extreme test resulted in high temperatures which were recorded at three locations on the cell, i.e., the cell wall, the boss (barrel of the compression seal), and a terminal. The results provide new information about the high-temperature and high-discharge-rate capabilities of nickel-hydrogen cells. This information also adds to the growing data base for single-layer zirconium-oxide-cloth (Zircar) separator cell designs.

Misfit-layered Bi1.85 Sr2 Co1.85 O7.7-δ for the hydrogen evolution reaction: beyond van der Waals heterostructures.

PubMed

Chua, Chun Kiang; Sofer, Zdeněk; Jankovský, Ondřej; Pumera, Martin

2015-03-16

Recent research on stable 2D nanomaterials has led to the discovery of new materials for energy-conversion and energy-storage applications. A class of layered heterostructures known as misfit-layered chalcogenides consists of well-defined atomic layers and has previously been applied as thermoelectric materials for use as high-temperature thermoelectric batteries. The performance of such misfit-layered chalcogenides in electrochemical applications, specifically the hydrogen evolution reaction, is currently unexplored. Herein, a misfit-layered chalcogenide consisting of CoO2 layers interleaved with an SrO-BiO-BiO-SrO rock-salt block and having the formula Bi1.85 Sr2 Co1.85 O7.7-δ is synthesized and examined for its structural and electrochemical properties. The hydrogen-evolution performance of misfit-layered Bi1.85 Sr2 Co1.85 O7.7-δ , which has an overpotential of 589 mV and a Tafel slope of 51 mV per decade, demonstrates the promising potential of misfit-layered chalcogenides as electrocatalysts instead of classical carbon. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mixture including hydrogen and hydrocarbon having pressure-temperature stability

NASA Technical Reports Server (NTRS)

Mao, Wendy L. (Inventor); Mao, Ho-Kwang (Inventor)

2009-01-01

The invention relates to a method of storing hydrogen that employs a mixture of hydrogen and a hydrocarbon that can both be used as fuel. In one embodiment, the method involves maintaining a mixture including hydrogen and a hydrocarbon in the solid state at ambient pressure and a temperature in excess of about 10 K.

Mixture including hydrogen and hydrocarbon having pressure-temperature stability

DOEpatents

Mao, Wendy L [Washington, DC; Mao, Ho-Kwang [Washington, DC

2009-08-18

The invention relates to a method of storing hydrogen that employs a mixture of hydrogen and a hydrocarbon that can both be used as fuel. In one embodiment, the method involves maintaining a mixture including hydrogen and a hydrocarbon in the solid state at ambient pressure and a temperature in excess of about 10 K.

Photoelectrochemical cells for conversion of solar energy to electricity and methods of their manufacture

DOEpatents

Skotheim, Terje

1984-04-10

A photoelectric device is disclosed which comprises first and second layers of semiconductive material, each of a different bandgap, with a layer of dry solid polymer electrolyte disposed between the two semiconductor layers. A layer of a polymer blend of a highly conductive polymer and a solid polymer electrolyte is further interposed between the dry solid polymer electrolyte and the first semiconductor layer. A method of manufacturing such devices is also disclosed.

An NMR Study of Biomimetic Fluorapatite – Gelatine Mesocrystals

PubMed Central

Vyalikh, Anastasia; Simon, Paul; Rosseeva, Elena; Buder, Jana; Scheler, Ulrich; Kniep, Rüdiger

2015-01-01

The mesocrystal system fluoroapatite—gelatine grown by double-diffusion is characterized by hierarchical composite structure on a mesoscale. In the present work we apply solid state NMR to characterize its structure on the molecular level and provide a link between the structural organisation on the mesoscale and atomistic computer simulations. Thus, we find that the individual nanocrystals are composed of crystalline fluorapatite domains covered by a thin boundary apatite-like layer. The latter is in contact with an amorphous layer, which fills the interparticle space. The amorphous layer is comprised of the organic matrix impregnated by isolated phosphate groups, Ca3F motifs and water molecules. Our NMR data provide clear evidence for the existence of precursor complexes in the gelatine phase, which were not involved in the formation of apatite crystals, proving hence theoretical predictions on the structural pre-treatment of gelatine by ion impregnation. The interfacial interactions, which may be described as the glue holding the composite materials together, comprise hydrogen bond interactions with the apatite PO43− groups. The reported results are in a good agreement with molecular dynamics simulations, which address the mechanisms of a growth control by collagen fibers, and with experimental observations of an amorphous cover layer in biominerals. PMID:26515127

Ultrathin platinum nanowires grown on single-layered nickel hydroxide with high hydrogen evolution activity.

PubMed

Yin, Huajie; Zhao, Shenlong; Zhao, Kun; Muqsit, Abdul; Tang, Hongjie; Chang, Lin; Zhao, Huijun; Gao, Yan; Tang, Zhiyong

2015-03-02

Design and synthesis of effective electrocatalysts for hydrogen evolution reaction in alkaline environments is critical to reduce energy losses in alkaline water electrolysis. Here we report a hybrid nanomaterial comprising of one-dimensional ultrathin platinum nanowires grown on two-dimensional single-layered nickel hydroxide. Judicious surface chemistry to generate the fully exfoliated nickel hydroxide single layers is explored to be the key for controllable growth of ultrathin platinum nanowires with diameters of about 1.8 nm. Impressively, this hybrid nanomaterial exhibits superior electrocatalytic activity for hydrogen evolution reaction in alkaline solution, which outperforms currently reported catalysts, and the obviously improved catalytic stability. We believe that this work may lead towards the development of single-layered metal hydroxide-based hybrid materials for applications in catalysis and energy conversion.

Citrate bridges between mineral platelets in bone

PubMed Central

Davies, Erika; Müller, Karin H.; Wong, Wai Ching; Pickard, Chris J.; Reid, David G.; Skepper, Jeremy N.; Duer, Melinda J.

2014-01-01

We provide evidence that citrate anions bridge between mineral platelets in bone and hypothesize that their presence acts to maintain separate platelets with disordered regions between them rather than gradual transformations into larger, more ordered blocks of mineral. To assess this hypothesis, we take as a model for a citrate bridging between layers of calcium phosphate mineral a double salt octacalcium phosphate citrate (OCP-citrate). We use a combination of multinuclear solid-state NMR spectroscopy, powder X-ray diffraction, and first principles electronic structure calculations to propose a quantitative structure for this material, in which citrate anions reside in a hydrated layer, bridging between apatitic layers. To assess the relevance of such a structure in native bone mineral, we present for the first time, to our knowledge, 17O NMR data on bone and compare them with 17O NMR data for OCP-citrate and other calcium phosphate minerals relevant to bone. The proposed structural model that we deduce from this work for bone mineral is a layered structure with thin apatitic platelets sandwiched between OCP-citrate–like hydrated layers. Such a structure can explain a number of known structural features of bone mineral: the thin, plate-like morphology of mature bone mineral crystals, the presence of significant quantities of strongly bound water molecules, and the relatively high concentration of hydrogen phosphate as well as the maintenance of a disordered region between mineral platelets. PMID:24706850

Liquid–solid phase transition of hydrogen and deuterium in silica aerogel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Cleve, E.; Worsley, M. A.; Kucheyev, S. O., E-mail: kucheyev@llnl.gov

2014-10-28

Behavior of hydrogen isotopes confined in disordered low-density nanoporous solids remains essentially unknown. Here, we use relaxation calorimetry to study freezing and melting of H{sub 2} and D{sub 2} in an ∼85%-porous base-catalyzed silica aerogel. We find that liquid–solid transition temperatures of both isotopes inside the aerogel are depressed. The phase transition takes place over a wide temperature range of ∼4 K and non-trivially depends on the liquid filling fraction, reflecting the broad pore size distribution in the aerogel. Undercooling is observed for both H{sub 2} and D{sub 2} confined inside the aerogel monolith. Results for H{sub 2} and D{sub 2}more » are extrapolated to tritium-containing hydrogens with the quantum law of corresponding states.« less

Carbon reactivation kinetics in GaAs: Its dependence on dopant precursor, doping level, and layer thickness

NASA Astrophysics Data System (ADS)

Mimila-Arroyo, J.; Bland, S.; Barbé, M.

2002-05-01

The reactivation kinetics of the acceptor behavior of carbon, its dependence on dopant precursors, doping level, layer thickness, and annealing temperature, as well as the behavior of carbon-hydrogen complexes in GaAs grown by metalorganic chemical vapor deposition are studied. Independent of the carbon source, in the "as grown" material, systematically carbon hydrogen complexes are present and the hole concentration is lower than the corresponding carbon concentration. The carbon reactivation kinetics was achieved by ex situ rapid thermal annealing through a series of multistage annealing experiments and assessed at each annealing stage by infrared absorption, hydrogen secondary ion mass spectroscopy profiling, and hole concentration measurements. Carbon reactivation occurs solely by the debonding of hydrogen from the isolated carbon acceptor and its out-diffusion from the sample. The carbon reactivation kinetics can be treated as a first order one with an activation energy, Ea=1.42±0.01 eV, independent of doping precursors, doping level, and layer thickness. The reactivation constant results to decrease as doping level and layer thickness increase. An empirical formula has been obtained that allows one to calculate the reactivation constant as a function of the carbon doping, layer thickness, and annealing temperature, allowing one to determine the optimal carbon reactivation conditions for any C:GaAs layer.

Hydrogen-Helium shock Radiation tests for Saturn Entry Probes

NASA Technical Reports Server (NTRS)

Cruden, Brett A.

2016-01-01

This paper describes the measurement of shock layer radiation in Hydrogen/Helium mixtures representative of that encountered by probes entering the Saturn atmosphere. Normal shock waves are measured in Hydrogen-Helium mixtures (89:11% by volume) at freestream pressures between 13-66 Pa (0.1-0.5 Torr) and velocities from 20-30 km/s. Radiance is quantified from the Vacuum Ultraviolet through Near Infrared. An induction time of several centimeters is observed where electron density and radiance remain well below equilibrium. Radiance is observed in front of the shock layer, the characteristics of which match the expected diffusion length of Hydrogen.

Effect of hydrogenation on the electrical and optical properties of CdZnTe substrates and HgCdTe epitaxial layers

NASA Astrophysics Data System (ADS)

Sitharaman, S.; Raman, R.; Durai, L.; Pal, Surendra; Gautam, Madhukar; Nagpal, Anjana; Kumar, Shiv; Chatterjee, S. N.; Gupta, S. C.

2005-12-01

In this paper, we report the experimental observations on the effect of plasma hydrogenation in passivating intrinsic point defects, shallow/deep levels and extended defects in low-resistivity undoped CdZnTe crystals. The optical absorption studies show transmittance improvement in the below gap absorption spectrum. Using variable temperature Hall measurement technique, the shallow defect level on which the penetrating hydrogen makes complex, has been identified. In 'compensated' n-type HgCdTe epitaxial layers, hydrogenation can improve the resistivity by two orders of magnitude.

Miniaturized Metal (Metal Alloy)/PdO(x)/SiC Hydrogen and Hydrocarbon Gas Sensors

NASA Technical Reports Server (NTRS)

Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

2008-01-01

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO(x)). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600 C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sided sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. Quarterly technical progress report for the period ending March 31, 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-12-31

The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with anmore » ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.« less

Synthesis and Stability of Lanthanum Superhydrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geballe, Zachary M.; Liu, Hanyu; Mishra, Ajay K.

Recent theoretical calculations predict that megabar pressure stabilizes very hydrogen-rich simple compounds having new clathrate-like structures and remarkable electronic properties including room-temperature superconductivity. X-ray diffraction and optical studies demonstrate that superhydrides of lanthanum can be synthesized with La atoms in an fcc lattice at 170 GPa upon heating to about 1000 K. The results match the predicted cubic metallic phase of LaH10 having cages of thirty-two hydrogen atoms surrounding each La atom. Upon decompression, the fcc-based structure undergoes a rhombohedral distortion of the La sublattice. The superhydride phases consist of an atomic hydrogen sublattice with H-H distances of about 1.1more » Å, which are close to predictions for solid atomic metallic hydrogen at these pressures. With stability below 200 GPa, the superhydride is thus the closest analogue to solid atomic metallic hydrogen yet to be synthesized and characterized.« less

Study of Hydrogen Production Method using Latent Heat of Liquefied Natural Gas

NASA Astrophysics Data System (ADS)

Ogawa, Masaru; Seki, Tatsuyoshi; Honda, Hiroshi; Nakamura, Motomu; Takatani, Yoshiaki

In recent years, Fuel Cell Electrical Vehicle is expected to improve urban environment. Particularly a hydrogen fuel type FCEV expected for urban use, because its excellent characters such as short startup time, high responsibility and zero emission. On the other hand, as far as hydrogen production is concerned, large amount of CO2 is exhausted into the atmosphere by the process of LNG reforming. In our research, we studied the utilization of LNG latent heat for hydrogen gas production process as well as liquefied hydrogen process. Furthermore, CO2---Capturing as liquid state or solid state from hydrogen gas production process by LNG is also studied. Results of research shows that LNG latent heat is very effect to cool hydrogen gas for conventional hydrogen liquefied process. However, the LNG latent heat is not available for LNG reforming process. If we want to use LNG latent heat for this process, we have to develop new hydrogen gas produce process. In this new method, both hydrogen and CO2 is cooled by LNG directly, and CO2 is removed from the reforming gas. In order to make this method practical, we should develop a new type heat-exchanger to prevent solid CO2 from interfering the performance of it.

Two-Dimensional Nanoporous Networks Formed by Liquid-to-Solid Transfer of Hydrogen-Bonded Macrocycles Built from DNA Bases.

PubMed

Bilbao, Nerea; Destoop, Iris; De Feyter, Steven; González-Rodríguez, David

2016-01-11

We present an approach that makes use of DNA base pairing to produce hydrogen-bonded macrocycles whose supramolecular structure can be transferred from solution to a solid substrate. A hierarchical assembly process ultimately leads to two-dimensional nanostructured porous networks that are able to host size-complementary guests. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fe–Ni solid solutions in nano-size dimensions: Effect of hydrogen annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Asheesh, E-mail: asheeshk@barc.gov.in; Meena, S.S.; Banerjee, S.

Highlights: • Fe–Ni solid solution with nano-size dimensions were prepared and characterized. • Both as prepared and hydrogenated solid solutions have FCC structure of Ni. • Paramagnetic and ferromagnetic domains coexist in these samples. - Abstract: Nanoparticles of Ni{sub 0.50}Fe{sub 0.50} and Ni{sub 0.75}Fe{sub 0.25} alloys were prepared by chemical reduction in ethylene glycol medium. XRD and {sup 57}Fe Mössbauer studies have confirmed the formation of Fe–Ni solid solution in nano-size dimensions with FCC structure. These samples consist of both ferromagnetic and paramagnetic domains which have been attributed to the coexistence of large and small particles as confirmed by atomicmore » force microscopic (AFM) and {sup 57}Fe Mössbauer spectroscopic studies. Improved extent of Fe–Fe exchange interaction existing in Ni{sub 0.50}Fe{sub 0.50} alloy compared to Ni{sub 0.75}Fe{sub 0.25} alloy explains the observed increase in the relative extent of ferromagnetic domains compared to paramagnetic domains in the former sample. Increase in the relative extent of ferromagnetic domains for hydrogenated alloys is due to increase in particle size brought about by the high temperature activation prior to hydrogenation.« less

SSH2S: Hydrogen storage in complex hydrides for an auxiliary power unit based on high temperature proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Baricco, Marcello; Bang, Mads; Fichtner, Maximilian; Hauback, Bjorn; Linder, Marc; Luetto, Carlo; Moretto, Pietro; Sgroi, Mauro

2017-02-01

The main objective of the SSH2S (Fuel Cell Coupled Solid State Hydrogen Storage Tank) project was to develop a solid state hydrogen storage tank based on complex hydrides and to fully integrate it with a High Temperature Proton Exchange Membrane (HT-PEM) fuel cell stack. A mixed lithium amide/magnesium hydride system was used as the main storage material for the tank, due to its high gravimetric storage capacity and relatively low hydrogen desorption temperature. The mixed lithium amide/magnesium hydride system was coupled with a standard intermetallic compound to take advantage of its capability to release hydrogen at ambient temperature and to ensure a fast start-up of the system. The hydrogen storage tank was designed to feed a 1 kW HT-PEM stack for 2 h to be used for an Auxiliary Power Unit (APU). A full thermal integration was possible thanks to the high operation temperature of the fuel cell and to the relative low temperature (170 °C) for hydrogen release from the mixed lithium amide/magnesium hydride system.

Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

PubMed Central

Kawasaki, Shin-ichiro; Suzuki, Akira

2013-01-01

Summary The inner surface of a metallic tube (i.d. 0.5 mm) was coated with a palladium (Pd)-based thin metallic layer by flow electroless plating. Simultaneous plating of Pd and silver (Ag) from their electroless-plating solution produced a mixed distributed bimetallic layer. Preferential acid leaching of Ag from the Pd–Ag layer produced a porous Pd surface. Hydrogenation of p-nitrophenol was examined in the presence of formic acid simply by passing the reaction solution through the catalytic tubular reactors. p-Aminophenol was the sole product of hydrogenation. No side reaction occurred. Reaction conversion with respect to p-nitrophenol was dependent on the catalyst layer type, the temperature, pH, amount of formic acid, and the residence time. A porous and oxidized Pd (PdO) surface gave the best reaction conversion among the catalytic reactors examined. p-Nitrophenol was converted quantitatively to p-aminophenol within 15 s of residence time in the porous PdO reactor at 40 °C. Evolution of carbon dioxide (CO2) was observed during the reaction, although hydrogen (H2) was not found in the gas phase. Dehydrogenation of formic acid did not occur to any practical degree in the absence of p-nitrophenol. Consequently, the nitro group was reduced via hydrogen transfer from formic acid to p-nitrophenol and not by hydrogen generated by dehydrogenation of formic acid. PMID:23843908

Catalytic fast pyrolysis of biomass impregnated with potassium phosphate in a hydrogen atmosphere for the production of phenol and activated carbon

NASA Astrophysics Data System (ADS)

Lu, Qiang; Zhang, Zhen-xi; Wang, Xin; Guo, Hao-qiang; Cui, Min-shu; Yang, Yong-ping

2018-02-01

A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K3PO4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K3PO4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K3PO4 at 550 oC in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO2 activation method, the specific surface area was as high as 1605 m2/g.

Catalytic Fast Pyrolysis of Biomass Impregnated with Potassium Phosphate in a Hydrogen Atmosphere for the Production of Phenol and Activated Carbon

PubMed Central

Lu, Qiang; Zhang, Zhen-xi; Wang, Xin; Guo, Hao-qiang; Cui, Min-shu; Yang, Yong-ping

2018-01-01

A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K3PO4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K3PO4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K3PO4 at 550°C in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO2 activation method, the specific surface area was as high as 1,605 m2/g. PMID:29515994

Catalytic Fast Pyrolysis of Biomass Impregnated with Potassium Phosphate in a Hydrogen Atmosphere for the Production of Phenol and Activated Carbon.

PubMed

Lu, Qiang; Zhang, Zhen-Xi; Wang, Xin; Guo, Hao-Qiang; Cui, Min-Shu; Yang, Yong-Ping

2018-01-01

A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K 3 PO 4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K 3 PO 4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K 3 PO 4 at 550°C in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO 2 activation method, the specific surface area was as high as 1,605 m 2 /g.

Integrated process for the solvent refining of coal

DOEpatents

Garg, Diwakar

1983-01-01

A process is set forth for the integrated liquefaction of coal by the catalytic solvent refining of a feed coal in a first stage to liquid and solid products and the catalytic hydrogenation of the solid product in a second stage to produce additional liquid product. A fresh inexpensive, throw-away catalyst is utilized in the second stage hydrogenation of the solid product and this catalyst is recovered and recycled for catalyst duty in the solvent refining stage without any activation steps performed on the used catalyst prior to its use in the solvent refining of feed coal.

Structure, photoluminescent properties and photocatalytic activities of a new Cd(II) metal-organic framework.

PubMed

Zhang, Cheng Yan; Ma, Wei Xing; Wang, Ming Yan; Yang, Xu Jie; Xu, Xing You

2014-01-24

A new metal-organic framework, [Cd(TDC)(bix)(H2O)]n (H2TDC = thiophene-2,5-dicarboxylic acid; bix = 1,4-bis(imidazol-1-ylmethyl)benzene), has been synthesized under hydrothermal conditions and structurally characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, UV-vis and single X-ray diffraction. Cd-MOF is a 2D infinite layer framework, which is further interconnected by hydrogen-bond interactions leading to a 3D supramolecular architecture. The photoluminescent properties of the Cd-MOF were investigated and this compound shows intense fluorescent emissions in the solid state. In addition, it exhibits good photocatalytic activities for the degradation of methyl organic under UV light irradiation. Copyright © 2013 Elsevier B.V. All rights reserved.

Immobilization of molecular catalysts in supported ionic liquid phases.

PubMed

Van Doorslaer, Charlie; Wahlen, Joos; Mertens, Pascal; Binnemans, Koen; De Vos, Dirk

2010-09-28

In a supported ionic liquid phase (SILP) catalyst system, an ionic liquid (IL) film is immobilized on a high-surface area porous solid and a homogeneous catalyst is dissolved in this supported IL layer, thereby combining the attractive features of homogeneous catalysts with the benefits of heterogeneous catalysts. In this review reliable strategies for the immobilization of molecular catalysts in SILPs are surveyed. In the first part, general aspects concerning the application of SILP catalysts are presented, focusing on the type of catalyst, support, ionic liquid and reaction conditions. Secondly, organic reactions in which SILP technology is applied to improve the performance of homogeneous transition-metal catalysts are presented: hydroformylation, metathesis reactions, carbonylation, hydrogenation, hydroamination, coupling reactions and asymmetric reactions.

Surface Design and Engineering Toward Wear-Resistant, Self-Lubricant Diamond Films and Coatings. Chapter 10

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1999-01-01

This chapter describes three studies on the surface design, surface engineering, and tribology of chemical-vapor-deposited (CVD) diamond films and coatings toward wear-resistant, self-lubricating diamond films and coatings. Friction mechanisms and solid lubrication mechanisms of CVD diamond are stated. Effects of an amorphous hydrogenated carbon on CVD diamond, an amorphous, nondiamond carbon surface layer formed on CVD diamond by carbon and nitrogen ion implantation, and a materials combination of cubic boron nitride and CVD diamond on the adhesion, friction, and wear behaviors of CVD diamond in ultrahigh vacuum are described. How surface modification and the selected materials couple improved the tribological functionality of coatings, giving low coefficient of friction and good wear resistance, is explained.

Electrochemical characterization of Fe-air rechargeable oxide battery in planar solid oxide cell stacks

NASA Astrophysics Data System (ADS)

Fang, Qingping; Berger, Cornelius M.; Menzler, Norbert H.; Bram, Martin; Blum, Ludger

2016-12-01

Iron-air rechargeable oxide batteries (ROB) comprising solid oxide cells (SOC) as energy converters and Fe/metal-oxide redox couples were characterized using planar SOC stacks. The charge and discharge of the battery correspond to the operations in the electrolysis and fuel cell modes, respectively, but with a stagnant atmosphere consisting of hydrogen and steam. A novel method was employed to establish the stagnant atmosphere for battery testing during normal SOC operation without complicated modification to the test bench and stack/battery concept. Manipulation of the gas compositions during battery operation was not necessary, but the influence of the leakage current from the testing system had to be considered. Batteries incorporating Fe2O3/8YSZ, Fe2O3/CaO and Fe2O3/ZrO2 storage materials were characterized at 800 °C. A maximum charge capacity of 30.4 Ah per layer (with an 80 cm2 active cell area) with ∼0.5 mol Fe was reached with a current of 12 A. The charge capacity lost 11% after ∼130 ROB cycles due to the increased agglomeration of active materials and formation of a dense oxide layer on the surface. The round trip efficiencies of the tested batteries were ≤84% due to the large internal resistance. With state-of-the-art cells, the round trip efficiency can be further improved.

Formulation of itraconazole nanococrystals and evaluation of their bioavailability in dogs.

PubMed

De Smet, Lieselotte; Saerens, Lien; De Beer, Thomas; Carleer, Robert; Adriaensens, Peter; Van Bocxlaer, Jan; Vervaet, Chris; Remon, Jean Paul

2014-05-01

The aim of the study is to increase the bioavailability of itraconazole (ITRA) using nanosized cocrystals prepared via wet milling of ITRA in combination with dicarboxylic acids. Wet milling was used in order to create a nanosuspension of ITRA in combination with dicarboxylic acids. After spray-drying and bead layering, solid state was characterized by MDSC, XRD, Raman and FT-IR. The release profiles and bioavailability of the nanococrystalline suspension, the spray-dried and bead layered formulation were evaluated. A monodisperse nanosuspension (549±51nm) of ITRA was developed using adipic acid and Tween®80. Solid state characterization indicated the formation of nanococrystals by hydrogen bounds between the triazole group of ITRA and the carboxyl group of adipic acid. A bioavailability study was performed in dogs. The faster drug release from the nanocrystal-based formulation was reflected in the in vivo results since Tmax of the formulations was obtained 3h after administration, while Tmax of the reference formulation was observed only 6h after administration. This fast release of ITRA was obtained by a dual concept: manufacturing of nanosized cocrystals of ITRA and adipic acid via wet milling. Formation of stable nanosized cocrystals via this approach seems a good alternative for amorphous systems to increase the solubility and obtain a fast drug release of BCS class II drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

Small stack performance of intermediate temperature-operating solid oxide fuel cells using stainless steel interconnects and anode-supported single cell

NASA Astrophysics Data System (ADS)

Bae, Joongmyeon; Lim, Sungkwang; Jee, Hyunjin; Kim, Jung Hyun; Yoo, Young-Sung; Lee, Taehee

We are developing 1 kW class solid oxide fuel cell (SOFC) system for residential power generation (RPG) application supported by Korean Government. Anode-supported single cells with thin electrolyte layer of YSZ (yttria-stabilized zirconia) or ScSZ (scandia-stabilized zirconia) for intermediate temperature operation (650-750 °C), respectively, were fabricated and small stacks were built and evaluated. The LSCF/ScSZ/Ni-YSZ single cell showed performance of 543 mW cm -2 at 650 °C and 1680 mW cm -2 at 750 °C. The voltage of 15-cell stack based on 5 cm × 5 cm single cell (LSM/YSZ/Ni-YSZ) at 150 mW was 12.5 V in hydrogen as fuel of 120 sccm per cell at 750 °C and decreased to about 10.9 V at 500 h operation time. A 5-cell stack based on the LSCF/YSZ/FL/Ni-YSZ showed the maximum power density of 30 W, 25 W and 20 W at 750 °C, 700 °C and 650 °C, respectively. LSCF/ScSZ/Ni-YSZ-based stack showed better performance than LSCF/YSZ/Ni-YSZ stack from the experiment temperature range. I- V characteristics by using hydrogen gas and reformate gas of methane as fuel were investigated at 750 °C in LSCF/ScSZ/FL/Ni-YSZ-based 5-cell stack.

Experimental measurements of the ground cloud effluents and cloud growth for the May 20, 1975, Titan 3C launch at Air Force Eastern Test Range, Florida

NASA Technical Reports Server (NTRS)

Gregory, G. L.; Storey, R. W., Jr.

1977-01-01

The experiment included surface level and airborne in situ cloud measurements of the exhaust effluents from the Titan IIIC solid rocket boosters. Simultaneous visible spectrum photographic pictures of the ground cloud as well as infrared imaging of the cloud were obtained to study the cloud rise, growth, and direction of travel within the earth's surface mixing layer. The NASA multilayer diffusion model predictions of cloud growth, direction of travel, and expected surface level effluent concentrations were made prior to launch and after launch using measured meteorological conditions. Prelaunch predictions were used to position the effluent monitoring instruments, and the postlaunch predictions were compared with the measured data. Measurement results showed that surface level effluent values were low, often below the detection limits of the instrumentation. The maximum surface level hydrogen chloride concentration measured 50 parts per billion at about 8 km from the launch pad. The maximum observed in-cloud (airborne measurement) hydrogen chloride concentration was 7 per million.

Study of the Charge Transfer Process of LaNi5 Type Electrodes in Ni-MH Batteries

NASA Astrophysics Data System (ADS)

Le, Xuan Que; Nguyen, Phu Thuy

2002-12-01

As a result of the charge process of LaNi5 type electrode, hydrogen is reversibly absorbed on the electrode surface. The process consists two principal steps. During the both processes, the first reaction step occurs in the interface solid/liquid, negatively charged, with high static electric field, where the double layer structure became more compact. The transfer of charge under high electric field depends on many factors, principally on compositions of the electrode materials. Effects on that of Co, Fe, Mn substitutes, with different concentrations, have been comparatively studied using electrochemical technique. The analyse of interface C -.V study results has been realised, respecting Mott-Schottky relation. Optimal contents of some additives have been discussed. Some advantages of the applied electrochemical methods have been confirmed. The mechanism of the charges transfer and of the hydrogen reversible storage in the crystal structure in the batteries has been discussed. With the proposed mechanism, one can more explicitly understand the difference of the magnetic effect of the electrode materials before and after charge-discharge process can be explained.

Nonepitaxial Thin-Film InP for Scalable and Efficient Photocathodes.

PubMed

Hettick, Mark; Zheng, Maxwell; Lin, Yongjing; Sutter-Fella, Carolin M; Ager, Joel W; Javey, Ali

2015-06-18

To date, some of the highest performance photocathodes of a photoelectrochemical (PEC) cell have been shown with single-crystalline p-type InP wafers, exhibiting half-cell solar-to-hydrogen conversion efficiencies of over 14%. However, the high cost of single-crystalline InP wafers may present a challenge for future large-scale industrial deployment. Analogous to solar cells, a thin-film approach could address the cost challenges by utilizing the benefits of the InP material while decreasing the use of expensive materials and processes. Here, we demonstrate this approach, using the newly developed thin-film vapor-liquid-solid (TF-VLS) nonepitaxial growth method combined with an atomic-layer deposition protection process to create thin-film InP photocathodes with large grain size and high performance, in the first reported solar device configuration generated by materials grown with this technique. Current-voltage measurements show a photocurrent (29.4 mA/cm(2)) and onset potential (630 mV) approaching single-crystalline wafers and an overall power conversion efficiency of 11.6%, making TF-VLS InP a promising photocathode for scalable and efficient solar hydrogen generation.

Atomistic Modeling of the Fluid-Solid Interface in Simple Fluids

NASA Astrophysics Data System (ADS)

Hadjiconstantinou, Nicolas; Wang, Gerald

2017-11-01

Fluids can exhibit pronounced structuring effects near a solid boundary, typically manifested in a layered structure that has been extensively shown to directly affect transport across the interface. We present and discuss several results from molecular-mechanical modeling and molecular-dynamics (MD) simulations aimed at characterizing the structure of the first fluid layer directly adjacent to the solid. We identify a new dimensionless group - termed the Wall number - which characterizes the degree of fluid layering, by comparing the competing effects of wall-fluid interaction and thermal energy. We find that in the layering regime, several key features of the first layer layer - including its distance from the solid, its width, and its areal density - can be described using mean-field-energy arguments, as well as asymptotic analysis of the Nernst-Planck equation. For dense fluids, the areal density and the width of the first layer can be related to the bulk fluid density using a simple scaling relation. MD simulations show that these results are broadly applicable and robust to the presence of a second confining solid boundary, different choices of wall structure and thermalization, strengths of fluid-solid interaction, and wall geometries.

Pyrolysis process for producing condensed stabilized hydrocarbons utilizing a beneficially reactive gas

DOEpatents

Durai-Swamy, Kandaswamy

1982-01-01

In a process for recovery of values contained in solid carbonaceous material, the solid carbonaceous material is comminuted and then subjected to pyrolysis, in the presence of a carbon containing solid particulate source of heat and a beneficially reactive transport gas in a transport flash pyrolysis reactor, to form a pyrolysis product stream. The pyrolysis product stream contains a gaseous mixture and particulate solids. The solids are separated from the gaseous mixture to form a substantially solids-free gaseous stream which comprises volatilized hydrocarbon free radicals newly formed by pyrolysis. Preferably the solid particulate source of heat is formed by oxidizing part of the separated particulate solids. The beneficially reactive transport gas inhibits the reactivity of the char product and the carbon-containing solid particulate source of heat. Condensed stabilized hydrocarbons are obtained by quenching the gaseous mixture stream with a quench fluid which contains a capping agent for stabilizing and terminating newly formed volatilized hydrocarbon free radicals. The capping agent is partially depleted of hydrogen by the stabilization and termination reaction. Hydrocarbons of four or more carbon atoms in the gaseous mixture stream are condensed. A liquid stream containing the stabilized liquid product is then treated or separated into various fractions. A liquid containing the hydrogen depleted capping agent is hydrogenated to form a regenerated capping agent. At least a portion of the regenerated capping agent is recycled to the quench zone as the quench fluid. In another embodiment capping agent is produced by the process, separated from the liquid product mixture, and recycled.

Progress in hydrogen energy; Proceedings of the National Workshop on Hydrogen Energy, New Delhi, India, July 4-6, 1985

NASA Astrophysics Data System (ADS)

Dahiya, R. P.

1987-06-01

The present conference on the development status of hydrogen energy technologies considers electrolytic hydrogen production, photoelectrolytic hydrogen production, microorganic hydrogen production, OTEC hydrogen production, solid-state materials for hydrogen storage, and a thin-film hydrogen storage system. Also discussed are the cryogenic storage of hydrogen; liquid hydrogen fuel for ground, air, and naval vehicles; hydrogen-fuel internal combustion engines; the use of hydrogen for domestic, commercial, and industrial applications; hydrogen fuel-cell development; enzyme electrodes for the use of hydrogen-rich fuels in biochemical fuel cells; an analysis of H2-O2 MHD generators; and hydrogen energy technology characterization and evaluation on the basis of an input-output structure.

Magnetic levitation of condensed hydrogen

NASA Technical Reports Server (NTRS)

Paine, C. G.; Seidel, G. M.

1991-01-01

Liquid and solid molecular hydrogen has been levitated using a pair of small superconducting solenoids. The hydrogen samples, up to 3 mm in dimension, were trapped in a magnetic potential having either a discrete minimum or a minimum in the form of a ring 1 cm in diameter. The hydrogen could be moved about in the magnetic trap by applying an electric field.

Non-Implanted Gallium-Arsenide and its Subsequent Annealing Effects.

NASA Astrophysics Data System (ADS)

Liou, Lih-Yeh

Infrared spectroscopy is used to study ion-implanted GaAs and its subsequent annealing effects. The damage in the implantation region causes a change in dielectric constant resulting in an infrared reflection spectrum which shows the interference pattern of a multilayer structure. Reflection data are fitted by values calculated from a physically realistic model by using computer codes. The first part in this work studies the solid state regrowth of amorphous GaAs made by Be implantation at -100(DEGREES)C. The regrowth temperature is around 200(DEGREES)C. The regrowth starts with a narrowing of the transition region and the transformation of the implanted layer from as-implanted amorphous (a-l) state to thermally-stablized amorphous (a-ll) state. The non-epitaxial recrystallization from both the surface and the interfacial region follows. The final regrown layer has a slightly higher refractive index than the crystalline value, indicating a high residual defect concentration. The temperature dependent regrowth velocity and the activation energy for this process are determined. The second part studies the free carrier activation in Be-implanted GaAs. Free holes are activated with prolonged annealing at 400(DEGREES)C ((TURN)50 hours) or a shorter time at higher temperature. The carrier contribution to the dielectric constant is calculated from the classical model and best fit to the reflection results show that the carrier profile can be approximated by a two half-Gaussians joined smoothly at their peaks. The peak position for the profile occurs deeper than that for the Be impurity profile measured by SIMS. The carrier distribution is speculated to be the result of the Be impurity, Ga vacancy and possible compensating defect distributions. The final part studies the free carrier removal by proton implantation in heavily doped, high carrier density, n-type GaAs. The as-implantation region is highly compensated until annealed at 550(DEGREES)C. After annealing between 300 and 400(DEGREES)C, the infrared results show a partially compensated region diffused deeply into substrate from the as-implanted region. The SIMS measurements show a well correlated hydrogen diffusion layer which suggests that the compensation defect is hydrogen related. After 500(DEGREES)C, the hydrogen diffusion layer is still observed, but the compensation layer has disappeared. The diffusion coefficient of the compensating defect and the activation energy for this process are determined. Carbon -implanted GaAs having a high carrier density substrate is also measured and compared with the H-implanted cases. (Copies available exclusively from Micrographics Department, Doheny Library, USC, Los Angeles, CA 90089 -0182.).

Lithium-ion batteries having conformal solid electrolyte layers

DOEpatents

Kim, Gi-Heon; Jung, Yoon Seok

2014-05-27

Hybrid solid-liquid electrolyte lithium-ion battery devices are disclosed. Certain devices comprise anodes and cathodes conformally coated with an electron insulating and lithium ion conductive solid electrolyte layer.

Thermal treatment of electronic waste in a fluidised bed and chemical digestion of solid products.

PubMed

Woynarowska, Amelia; Żukowski, Witold; Żelazny, Sylwester

2016-07-01

The article presents the results of e-waste thermal treatment in a fluidised bed reactor and solid products digestion under acidic conditions. During the processes, measurements of carbon monoxide, carbon dioxide, volatile organic compounds, nitrogen oxides, sulphur dioxide, hydrogen chloride, hydrogen bromide, hydrogen cyanide, ammonia, phenol, aliphatic and aromatic hydrocarbons, hydrogen fluoride and phosgene were carried out. Several digestion tests of the solid residue in sulphuric acid (VI) at 25 °C-65 °C, for 55 min-24 h were conducted. In each case, the dilution method was used, i.e. preliminary digestion in concentrated sulphuric acid (VI) (95%) for 40 min, and then dilution to expected concentrations (30%-50%). Most preferred results were obtained using sulphuric acid (VI) with a target concentration of 40% at 65 °C, where the leaching degrees were 76.56% for copper, 71.67% for iron, 91.89% for zinc and 97.40% for tin. The time necessary to effectively carry out the digestion process was 220 min. © The Author(s) 2016.

Calcium looping process for high purity hydrogen production integrated with capture of carbon dioxide, sulfur and halides

DOEpatents

Ramkumar, Shwetha; Fan, Liang-Shih

2013-07-30

A process for producing hydrogen comprising the steps of: (i) gasifying a fuel into a raw synthesis gas comprising CO, hydrogen, steam, sulfur and halide contaminants in the form of H.sub.2S, COS, and HX, wherein X is a halide; (ii) passing the raw synthesis gas through a water gas shift reactor (WGSR) into which CaO and steam are injected, the CaO reacting with the shifted gas to remove CO.sub.2, sulfur and halides in a solid-phase calcium-containing product comprising CaCO.sub.3, CaS and CaX.sub.2; (iii) separating the solid-phase calcium-containing product from an enriched gaseous hydrogen product; and (iv) regenerating the CaO by calcining the solid-phase calcium-containing product at a condition selected from the group consisting of: in the presence of steam, in the presence of CO.sub.2, in the presence of synthesis gas, in the presence of H.sub.2 and O.sub.2, under partial vacuum, and combinations thereof.

Solid oxide fuel cell operable over wide temperature range

DOEpatents

Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

2001-01-01

Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

Interfacial material for solid oxide fuel cell

DOEpatents

Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

1999-01-01

Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

Hydrogenation of passivated contacts

DOEpatents

Nemeth, William; Yuan, Hao-Chih; LaSalvia, Vincenzo; Stradins, Pauls; Page, Matthew R.

2018-03-06

Methods of hydrogenation of passivated contacts using materials having hydrogen impurities are provided. An example method includes applying, to a passivated contact, a layer of a material, the material containing hydrogen impurities. The method further includes subsequently annealing the material and subsequently removing the material from the passivated contact.

Hydrogen in thin Pd-based layers deposited on reticulated vitreous carbon-A new system for electrochemical capacitors

NASA Astrophysics Data System (ADS)

Łukaszewski, M.; Żurowski, A.; Czerwiński, A.

Reticulated vitreous carbon (RVC) has been used as a matrix for electrodeposition of thin layers of Pd and Pd-rich Pd-Rh alloys. It was found that RVC substrate does not affect qualitatively hydrogen absorption behavior of Pd-based deposits. Similarly to thin Pd or Pd alloy layers deposited on Au wires, the α-β phase transition controls the overall rate of hydrogen absorption and desorption into/from Pd-based/RVC electrodes. The possibility of the application of these materials as phase charging-discharging systems was investigated. The values of specific pseudocapacitance, specific power and specific energy were comparable with those for supercapacitors utilizing various redox reactions.

Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

NASA Technical Reports Server (NTRS)

Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

2011-01-01

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x ). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

NASA Technical Reports Server (NTRS)

Xu, Jennifer C. (Inventor); Hunter, Gary W. (Inventor); Lukco, Dorothy (Inventor)

2008-01-01

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

Crystal structure of solid molecular hydrogen under high pressures

NASA Astrophysics Data System (ADS)

Cui, T.; Ma, Y.; Zou, G.

2002-11-01

In an effort to achieve a comprehensive understanding of the structure of dense H2, we have performed path-integral Monte Carlo simulations for three combinations of pressures and temperatures corresponding to three phases of solid hydrogen. Our results suggest three kinds of distribution of molecules: orientationally disordered hexagonal close packed (hcp), orientationally ordered hcp with Pa3-type local orientation order and orientationally ordered orthorhombic structure of Cmca symmetry, for the three phases.

NO ICE HYDROGENATION: A SOLID PATHWAY TO NH{sub 2}OH FORMATION IN SPACE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congiu, Emanuele; Dulieu, Francois; Chaabouni, Henda

2012-05-01

Icy dust grains in space act as catalytic surfaces onto which complex molecules form. These molecules are synthesized through exothermic reactions from precursor radicals and, mostly, hydrogen atom additions. Among the resulting products are species of biological relevance, such as hydroxylamine-NH{sub 2}OH-a precursor molecule in the formation of amino acids. In this Letter, laboratory experiments are described that demonstrate NH{sub 2}OH formation in interstellar ice analogs for astronomically relevant temperatures via successive hydrogenation reactions of solid nitric oxide (NO). Inclusion of the experimental results in an astrochemical gas-grain model proves the importance of a solid-state NO+H reaction channel as amore » starting point for prebiotic species in dark interstellar clouds and adds a new perspective to the way molecules of biological importance may form in space.« less

Method for improving the durability of ion insertion materials

DOEpatents

Lee, Se-Hee; Tracy, C. Edwin; Cheong, Hyeonsik M.

2002-01-01

The invention provides a method of protecting an ion insertion material from the degradative effects of a liquid or gel-type electrolyte material by disposing a protective, solid ion conducting, electrically insulating, layer between the ion insertion layer and the liquid or gel-type electrolyte material. The invention further provides liquid or gel-type electrochemical cells having improved durability having a pair of electrodes, a pair of ion insertion layers sandwiched between the pair of electrodes, a pair of solid ion conducting layers sandwiched between the ion insertion layers, and a liquid or gel-type electrolyte material disposed between the solid ion conducting layers, where the solid ion conducting layer minimizes or prevents degradation of the faces of the ion insertion materials facing the liquid or gel-type electrolyte material. Electrochemical cells of this invention having increased durability include secondary lithium batteries and electrochromic devices.

Catalytic hydrotreating process

DOEpatents

Karr, Jr., Clarence; McCaskill, Kenneth B.

1978-01-01

Carbonaceous liquids boiling above about 300.degree. C such as tars, petroleum residuals, shale oils and coal-derived liquids are catalytically hydrotreated by introducing the carbonaceous liquid into a reaction zone at a temperature in the range of 300.degree. to 450.degree. C and a pressure in the range of 300 to 4000 psig for effecting contact between the carbonaceous liquid and a catalytic transition metal sulfide in the reaction zone as a layer on a hydrogen permeable transition metal substrate and then introducing hydrogen into the reaction zone by diffusing the hydrogen through the substrate to effect the hydrogenation of the carbonaceous liquid in the presence of the catalytic sulfide layer.

Impact of hydrogen dilution on optical properties of intrinsic hydrogenated amorphous silicon films prepared by high density plasma chemical vapor deposition for solar cell applications

NASA Astrophysics Data System (ADS)

Chen, Huai-Yi; Lee, Yao-Jen; Chang, Chien-Pin; Koo, Horng-Show; Lai, Chiung-Hui

2013-01-01

P-i-n single-junction hydrogenated amorphous silicon (a-Si:H) thin film solar cells were successfully fabricated in this study on a glass substrate by high density plasma chemical vapor deposition (HDP-CVD) at low power of 50 W, low temperature of 200°C and various hydrogen dilution ratios (R). The open circuit voltage (Voc ), short circuit current density (Jsc ), fill factor (FF) and conversion efficiency (η) of the solar cell as well as the refractive index (n) and absorption coefficient (α) of the i-layer at 600 nm wavelength rise with increasing R until an abrupt drop at high hydrogen dilution, i.e. R > 0.95. However, the optical energy bandgap (Eg ) of the i-layer decreases with the R increase. Voc and α are inversely correlated with Eg . The hydrogen content affects the i-layer and p/i interface quality of the a-Si:H thin film solar cell with an optimal value of R = 0.95, which corresponds to solar cell conversion efficiency of 3.85%. The proposed a-Si:H thin film solar cell is expected to be improved in performance.

Tandem junction amorphous silicon solar cells

DOEpatents

Hanak, Joseph J.

1981-01-01

An amorphous silicon solar cell has an active body with two or a series of layers of hydrogenated amorphous silicon arranged in a tandem stacked configuration with one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon arranged in tandem configuration can have the same bandgap or differing bandgaps.

Evaluation of stress stabilities in amorphous In-Ga-Zn-O thin-film transistors: Effect of passivation with Si-based resin

NASA Astrophysics Data System (ADS)

Ochi, Mototaka; Hino, Aya; Goto, Hiroshi; Hayashi, Kazushi; Fujii, Mami N.; Uraoka, Yukiharu; Kugimiya, Toshihiro

2018-02-01

Fabrication process conditions of a passivation (PV) layer correlated with stress stabilities of amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs). In etch-stop layer (ESL)-TFTs, by inserting a Si-based resin between SiN x and SiO x PV layers, the peak intensity in the photoinduced transient spectroscopy (PITS) spectrum was notably reduced. This suggested the suppression of hydrogen incorporation into a-IGZO, which led to the improvement of stability under negative bias thermal illumination stress (NBTIS). In contrast, the hydrogen-related defects in the a-IGZO were easily formed by the back-channel etch (BCE) process. Furthermore, it was found that, under NBTIS, the transfer curves of the BCE-TFTs shifted in parallel owing to the positive fixed charge located in the back channel of the a-IGZO TFTs. The hump-shaped shift increased with stress time. This is because hydrogen atoms located at the back-channel surfaces of the a-IGZO and/or PV layers were incorporated into the channel region of the BCE-TFTs and induced the hydrogen-related defects.

Evidence for Bulk Ripplocations in Layered Solids

NASA Astrophysics Data System (ADS)

Gruber, Jacob; Lang, Andrew C.; Griggs, Justin; Taheri, Mitra L.; Tucker, Garritt J.; Barsoum, Michel W.

2016-09-01

Plastically anisotropic/layered solids are ubiquitous in nature and understanding how they deform is crucial in geology, nuclear engineering, microelectronics, among other fields. Recently, a new defect termed a ripplocation-best described as an atomic scale ripple-was proposed to explain deformation in two-dimensional solids. Herein, we leverage atomistic simulations of graphite to extend the ripplocation idea to bulk layered solids, and confirm that it is essentially a buckling phenomenon. In contrast to dislocations, bulk ripplocations have no Burgers vector and no polarity. In graphite, ripplocations are attracted to other ripplocations, both within the same, and on adjacent layers, the latter resulting in kink boundaries. Furthermore, we present transmission electron microscopy evidence consistent with the existence of bulk ripplocations in Ti3SiC2. Ripplocations are a topological imperative, as they allow atomic layers to glide relative to each other without breaking the in-plane bonds. A more complete understanding of their mechanics and behavior is critically important, and could profoundly influence our current understanding of how graphite, layered silicates, the MAX phases, and many other plastically anisotropic/layered solids, deform and accommodate strain.

Fluid transition layer between rigid solute and liquid solvent: is there depletion or enrichment?

PubMed

Djikaev, Yuri S; Ruckenstein, Eli

2016-03-21

The fluid layer between solute and liquid solvent is studied by combining the density functional theory with the probabilistic hydrogen bond model. This combination allows one to obtain the equilibrium distribution of fluid molecules, taking into account the hydrogen bond contribution to the external potential whereto they are subjected near the solute. One can find the effective width of the fluid solvent-solute transition layer and fluid average density in that layer, and determine their dependence on temperature, solvent-solute affinity, vicinal hydrogen bond (hb) energy alteration ratio, and solute radius. Numerical calculations are performed for the solvation of a plate and spherical solutes of four different radii in two model solvents (associated liquid and non-associated one) in the temperature range from 293 K to 333 K for various solvent-solute affinities and hydrogen bond energy alteration ratios. The predictions of our model for the effective width and average density of the transition layer are consistent with experiments and simulations. The small-to-large crossover lengthscale for hydrophobic hydration is expected to be about 3-5 nm. Remarkably, characterizing the transition layer with the average density, one can observe that for small hydrophobes, the transition layer becomes enriched with rather than depleted of fluid when the solvent-solute affinity and hb-energy alteration ratio become large enough. The boundary values of solvent-solute affinity and hb-energy alteration ratio, needed for the "depletion-to-enrichment" crossover (in the smoothed density sense), are predicted to decrease with increasing temperature.

Ejection of the Massive Hydrogen-rich Envelope Timed with the Collapse of the Stripped SN 2014C

PubMed Central

Margutti, Raffaella; Kamble, A.; Milisavljevic, D.; Zapartas, E.; de Mink, S. E.; Drout, M.; Chornock, R.; Risaliti, G.; Zauderer, B. A.; Bietenholz, M.; Cantiello, M.; Chakraborti, S.; Chomiuk, L.; Fong, W.; Grefenstette, B.; Guidorzi, C.; Kirshner, R.; Parrent, J. T.; Patnaude, D.; Soderberg, A. M.; Gehrels, N. C.; Harrison, F.

2017-01-01

We present multi-wavelength observations of SN 2014C during the first 500 days. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays ~40 keV. SN 2014C shows ordinary explosion parameters (Ek ~ 1.8 × 1051 erg and Mej ~ 1.7 M⊙). However, over an ~1 year timescale, SN 2014C evolved from an ordinary hydrogen-poor supernova into a strongly interacting, hydrogen-rich supernova, violating the traditional classification scheme of type-I versus type-II SNe. Signatures of the SN shock interaction with a dense medium are observed across the spectrum, from radio to hard X-rays, and revealed the presence of a massive shell of ~1 M⊙of hydrogen-rich material at ~6 × 1016 cm. The shell was ejected by the progenitor star in the decades to centuries before collapse. This result challenges current theories of massive star evolution, as it requires a physical mechanism responsible for the ejection of the deepest hydrogen layer of H-poor SN progenitors synchronized with the onset of stellar collapse. Theoretical investigations point at binary interactions and/or instabilities during the last nuclear burning stages as potential triggers of the highly time-dependent mass loss. We constrain these scenarios utilizing the sample of 183 SNe Ib/c with public radio observations. Our analysis identifies SN 2014C-like signatures in ~10% of SNe. This fraction is reasonably consistent with the expectation from the theory of recent envelope ejection due to binary evolution if the ejected material can survive in the close environment for 103–104 years. Alternatively, nuclear burning instabilities extending to core C-burning might play a critical role. PMID:28684881

Icosahedral quasicrystalline (Ti₁.₆V₀.₄Ni)₁₀₀₋xScx alloys: Synthesis, structure and their application in Ni-MH batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Wen; State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, CAS, Changchun 130022, Jilin; Yi, Jianhong

2013-06-01

Thanks to the revolutionary discovery of 5-fold symmetry contributed by Shechtman, quasicrystal is now recognized as another solid-state existing form. As the second largest class of quasicrystals, titanium-based icosahedral quasicrystals are very promising for hydrogen storage applications owing to their inherent abundant interstitial sites and favorable hydrogen-metal chemistry. In this context, (Ti₁.₆V₀.₄Ni)₁₀₀₋xScx (x=0.5–6) quaternary icosahedral quasicrystals have been successfully synthesized via arc-melting and subsequent melt-spinning techniques, and then their electrochemical performance toward hydrogen is explored. When the molar ratio of Sc addition is under 1%, a maximum discharge capacity of about 270 mA h g⁻¹ can be delivered. With furthermore » increasing Sc amount to 6%, good cycling stability as well as significantly retarded self-discharge rate (capacity retention 94% after 24 h relaxation) is observed. But meanwhile, the discharge capacities fall into 250-240 mA h g⁻¹, and the electrocatalytic activity improvement is highly demanded. - Graphical abstract: Quasicrystalline Ti–V–Ni–Sc hydrogen storage materials: Sc addition into Ti₁.₆V₀.₄Ni alloy forms the icosahedral phase (see picture). With optimal Sc dosage, the anodic cycling stability and self-discharge property are greatly enhanced. - Highlights: • Crystalline disallowed 5-fold symmetry is present in (Ti₁.₆V₀.₄Ni)₁₀₀₋xScx alloys. • Ti-based metastable quasicrystalline alloys can store hydrogen electrochemically. • A maximum discharge capacity of 270 mA h g⁻¹ can be delivered. • Advantageous cycle stability and self-discharge property benefit from Sc addition. • Ti and V dissolution is suppressed by an oxide layer resulting from Sc corrosion.« less

Hubble Sees a “Behemoth” Bleeding Atmosphere Around a Warm Exoplanet

NASA Image and Video Library

2015-06-24

Astronomers using NASA’s Hubble Space Telescope have discovered an immense cloud of hydrogen dubbed “The Behemoth” bleeding from a planet orbiting a nearby star. The enormous, comet-like feature is about 50 times the size of the parent star. The hydrogen is evaporating from a warm, Neptune-sized planet, due to extreme radiation from the star. This phenomenon has never been seen around an exoplanet so small. It may offer clues to how other planets with hydrogen-enveloped atmospheres could have their outer layers evaporated by their parent star, leaving behind solid, rocky cores. Hot, rocky planets such as these that roughly the size of Earth are known as Hot-Super Earths. “This cloud is very spectacular, though the evaporation rate does not threaten the planet right now,” explains the study’s leader, David Ehrenreich of the Observatory of the University of Geneva in Switzerland. “But we know that in the past, the star, which is a faint red dwarf, was more active. This means that the planet evaporated faster during its first billion years of existence because of the strong radiation from the young star. Overall, we estimate that it may have lost up to 10 percent of its atmosphere over the past several billion years.” Caption: This artist's concept shows "The Behemoth," an enormous comet-like cloud of hydrogen bleeding off of a warm, Neptune-sized planet just 30 light-years from Earth. Also depicted is the parent star, which is a faint red dwarf named GJ 436. The hydrogen is evaporating from the planet due to extreme radiation from the star. A phenomenon this large has never before been seen around any exoplanet. Credits: NASA, ESA, and G. Bacon (STScI)

Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition

PubMed Central

Nakayama, Hirokazu; Hayashi, Aki

2014-01-01

The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids. PMID:25080007

Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition.

PubMed

Nakayama, Hirokazu; Hayashi, Aki

2014-07-30

The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

Probing hydrogen bond networks in half-sandwich Ru(II) building blocks by a combined 1H DQ CRAMPS solid-state NMR, XRPD, and DFT approach.

PubMed

Chierotti, Michele R; Gobetto, Roberto; Nervi, Carlo; Bacchi, Alessia; Pelagatti, Paolo; Colombo, Valentina; Sironi, Angelo

2014-01-06

The hydrogen bond network of three polymorphs (1α, 1β, and 1γ) and one solvate form (1·H2O) arising from the hydration-dehydration process of the Ru(II) complex [(p-cymene)Ru(κN-INA)Cl2] (where INA is isonicotinic acid), has been ascertained by means of one-dimensional (1D) and two-dimensional (2D) double quantum (1)H CRAMPS (Combined Rotation and Multiple Pulses Sequences) and (13)C CPMAS solid-state NMR experiments. The resolution improvement provided by homonuclear decoupling pulse sequences, with respect to fast MAS experiments, has been highlighted. The solid-state structure of 1γ has been fully characterized by combining X-ray powder diffraction (XRPD), solid-state NMR, and periodic plane-wave first-principles calculations. None of the forms show the expected supramolecular cyclic dimerization of the carboxylic functions of INA, because of the presence of Cl atoms as strong hydrogen bond (HB) acceptors. The hydration-dehydration process of the complex has been discussed in terms of structure and HB rearrangements.

Lowering the temperature of solid oxide fuel cells.

PubMed

Wachsman, Eric D; Lee, Kang Taek

2011-11-18

Fuel cells are uniquely capable of overcoming combustion efficiency limitations (e.g., the Carnot cycle). However, the linking of fuel cells (an energy conversion device) and hydrogen (an energy carrier) has emphasized investment in proton-exchange membrane fuel cells as part of a larger hydrogen economy and thus relegated fuel cells to a future technology. In contrast, solid oxide fuel cells are capable of operating on conventional fuels (as well as hydrogen) today. The main issue for solid oxide fuel cells is high operating temperature (about 800°C) and the resulting materials and cost limitations and operating complexities (e.g., thermal cycling). Recent solid oxide fuel cells results have demonstrated extremely high power densities of about 2 watts per square centimeter at 650°C along with flexible fueling, thus enabling higher efficiency within the current fuel infrastructure. Newly developed, high-conductivity electrolytes and nanostructured electrode designs provide a path for further performance improvement at much lower temperatures, down to ~350°C, thus providing opportunity to transform the way we convert and store energy.

Hydrogen uptake causes molecular "avalanches" in palladium | Argonne

Science.gov Websites

experimental and calculated strain distributions in the hydrogen-poor phase. The strains are consistent with a trapped hydrogen-rich surface layer. Middle: Comparison between experimental and calculated strain transformation. Comparison between experimental and calculated strain distributions in the hydrogen-poor phase

Calculation of eddy viscosity in a compressible turbulent boundary layer with mass injection and chemical reaction, volume 1. [theoretical analysis

NASA Technical Reports Server (NTRS)

Omori, S.

1973-01-01

The turbulent kinetic energy equation is coupled with boundary layer equations to solve the characteristics of compressible turbulent boundary layers with mass injection and combustion. The Reynolds stress is related to the turbulent kinetic energy using the Prandtl-Wieghardt formulation. When a lean mixture of hydrogen and nitrogen is injected through a porous plate into the subsonic turbulent boundary layer of air flow and ignited by external means, the turbulent kinetic energy increases twice as much as that of noncombusting flow with the same mass injection rate of nitrogen. The magnitudes of eddy viscosity between combusting and noncombusting flows with injection, however, are almost the same due to temperature effects, while the distributions are different. The velocity profiles are significantly affected by combustion; that is, combustion alters the velocity profile as if the mass injection rate is increased, reducing the skin-friction as a result of a smaller velocity gradient at the wall. If pure hydrogen as a transpiration coolant is injected into a rocket nozzle boundary layer flow of combustion products, the temperature drops significantly across the boundary layer due to the high heat capacity of hydrogen. At a certain distance from the wall, hydrogen reacts with the combustion products, liberating an extensive amount of heat. The resulting large increase in temperature reduces the eddy viscosity in this region.

Hydrogen-Induced Plastic Deformation in ZnO

NASA Astrophysics Data System (ADS)

Lukáč, F.; Čížek, J.; Vlček, M.; Procházka, I.; Anwand, W.; Brauer, G.; Traeger, F.; Rogalla, D.; Becker, H.-W.

In the present work hydrothermally grown ZnO single crystals covered with Pd over-layer were electrochemically loaded with hydrogen and the influence of hydrogen on ZnO micro structure was investigated by positron annihilation spectroscopy (PAS). Nuclear reaction analysis (NRA) was employed for determination of depth profile of hydrogen concentration in the sample. NRA measurements confirmed that a substantial amount of hydrogen was introduced into ZnO by electrochemical charging. The bulk hydrogen concentration in ZnO determined by NRA agrees well with the concentration estimated from the transported charge using the Faraday's law. Moreover, a subsurface region with enhanced hydrogen concentration was found in the loaded crystals. Slow positron implantation spectroscopy (SPIS) investigations of hydrogen-loaded crystal revealed enhanced concentration of defects in the subsurface region. This testifies hydrogen-induced plastic deformation of the loaded crystal. Absorbed hydrogen causes a significant lattice expansion. At low hydrogen concentrations this expansion is accommodated by elastic straining, but at higher concentrations hydrogen-induced stress exceeds the yield stress in ZnO and plastic deformation of the loaded crystal takes place. Enhanced hydrogen concentration detected in the subsurface region by NRA is, therefore, due to excess hydrogen trapped at open volume defects introduced by plastic deformation. Moreover, it was found that hydrogen-induced plastic deformation in the subsurface layer leads to typical surface modification: formation of hexagonal shape pyramids on the surface due to hydrogen-induced slip in the [0001] direction.

Supramolecular structures and assembly and luminescent properties of quinacridone derivatives.

PubMed

Ye, Kaiqi; Wang, Jia; Sun, Hui; Liu, Yu; Mu, Zhongcheng; Li, Fei; Jiang, Shimei; Zhang, Jingying; Zhang, Hongxing; Wang, Yue; Che, Chi-Ming

2005-04-28

The synthesis and single-crystal X-ray structures of two quinacridone derivatives, N,N'-di(n-butyl)quinacridone (1) and N,N'-di(n-butyl)-1,3,8,10-tetramethylquinacridone (2), are reported, and the 1H NMR, absorption, photoluminescent (PL), and electroluminescent (EL) characteristics are presented. Both these crystal structures are characterized by intermolecular pi...pi and hydrogen bonding interactions. The intermolecular pi...pi interactions lead to the formation of molecular columns in the solids of 1 and 2, and the interplanar contact distances between two adjacent molecules are 3.48 and 3.55 angstroms, respectively. Crystals of 1 display shorter intermolecular pi...pi contacts and higher density than 2. These results suggest that tighter intermolecular interactions exist in 1. The 1H NMR, absorption, and PL spectra of 1 and 2 in solutions exhibit concentration-dependent properties. The PL quantum yields of 1 in solutions decrease more quickly with the increase of concentration compared to that of 2 in solutions. For solid thin films of Alq3:1 (Alq3 = tris(8-hydroxyquinolinato)aluminum), emission intensities dramatically decrease and obvious red shifts are observed when the dopant concentration is above 4.2%, while for films of Alq3:2, a similar phenomenon occurs when the concentration is above 6.7%. EL devices with Alq3:1 as emitting layer only show high efficiencies (20.3-14.5 cd/A) within the narrow dopant concentration range of 0.5-1.0%. In contrast, high efficiencies (21.5-12.0 cd/A) are achieved for a wider dopant concentration range of 0.5-5.0% when Alq3:2 films are employed as emitting layer. The different PL and EL concentration-dependent properties of the solid thin films Alq3:1 and Alq3:2 are attributed to their different molecular packing characteristics in the solid state.

Detection of hydrogen dissolved in acrylonitrile butadiene rubber by 1H nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Nishimura, Shin; Fujiwara, Hirotada

2012-01-01

Rubber materials, which are used for hydrogen gas seal, can dissolve hydrogen during exposure in high-pressure hydrogen gas. Dissolved hydrogen molecules were detected by solid state 1H NMR of the unfilled vulcanized acrylonitrile butadiene rubber. Two signals were observed at 4.5 ppm and 4.8 ppm, which were assignable to dissolved hydrogen, in the 1H NMR spectrum of NBR after being exposed 100 MPa hydrogen gas for 24 h at room temperature. These signals were shifted from that of gaseous hydrogen molecules. Assignment of the signals was confirmed by quantitative estimation of dissolved hydrogen and peak area of the signals.

Prediction of Ablation Rates from Solid Surfaces Exposed to High Temperature Gas Flow

NASA Technical Reports Server (NTRS)

Akyuzlu, Kazim M.; Coote, David

2013-01-01

A mathematical model and a solution algorithm is developed to study the physics of high temperature heat transfer and material ablation and identify the problems associated with the flow of hydrogen gas at very high temperatures and velocities through pipes and various components of Nuclear Thermal Rocket (NTR) motors. Ablation and melting can be experienced when the inner solid surface of the cooling channels and the diverging-converging nozzle of a Nuclear Thermal Rocket (NTR) motor is exposed to hydrogen gas flow at temperatures around 2500 degrees Kelvin and pressures around 3.4 MPa. In the experiments conducted on typical NTR motors developed in 1960s, degradation of the cooling channel material (cracking in the nuclear fuel element cladding) and in some instances melting of the core was observed. This paper presents the results of a preliminary study based on two types of physics based mathematical models that were developed to simulate the thermal-hydrodynamic conditions that lead to ablation of the solid surface of a stainless steel pipe exposed to high temperature hydrogen gas near sonic velocities. One of the proposed models is one-dimensional and assumes the gas flow to be unsteady, compressible and viscous. An in-house computer code was developed to solve the conservations equations of this model using a second-order accurate finite-difference technique. The second model assumes the flow to be three-dimensional, unsteady, compressible and viscous. A commercial CFD code (Fluent) was used to solve the later model equations. Both models assume the thermodynamic and transport properties of the hydrogen gas to be temperature dependent. In the solution algorithm developed for this study, the unsteady temperature of the pipe is determined from the heat equation for the solid. The solid-gas interface temperature is determined from an energy balance at the interface which includes heat transfer from or to the interface by conduction, convection, radiation, and ablation. Two different ablation models are proposed to determine the heat loss from the solid surface due to the ablation of the solid material. Both of them are physics based. Various numerical simulations were carried out using both models to predict the temperature distribution in the solid and in the gas flow, and then predict the ablation rates at a typical NTR motor hydrogen gas temperature and pressure. Solid mass loss rate per foot of a pipe was also calculated from these predictions. The results are presented for fully developed turbulent flow conditions in a sample SS pipe with a 6 inch diameter.

Compact hydrogen production systems for solid polymer fuel cells

NASA Astrophysics Data System (ADS)

Ledjeff-Hey, K.; Formanski, V.; Kalk, Th.; Roes, J.

Generally there are several ways to produce hydrogen gas from carbonaceous fuels like natural gas, oil or alcohols. Most of these processes are designed for large-scale industrial production and are not suitable for a compact hydrogen production system (CHYPS) in the power range of 1 kW. In order to supply solid polymer fuel cells (SPFC) with hydrogen, a compact fuel processor is required for mobile applications. The produced hydrogen-rich gas has to have a low level of harmful impurities; in particular the carbon monoxide content has to be lower than 20 ppmv. Integrating the reaction step, the gas purification and the heat supply leads to small-scale hydrogen production systems. The steam reforming of methanol is feasible at copper catalysts in a low temperature range of 200-350°C. The combination of a small-scale methanol reformer and a metal membrane as purification step forms a compact system producing high-purity hydrogen. The generation of a SPFC hydrogen fuel gas can also be performed by thermal or catalytic cracking of liquid hydrocarbons such as propane. At a temperature of 900°C the decomposition of propane into carbon and hydrogen takes place. A fuel processor based on this simple concept produces a gas stream with a hydrogen content of more than 90 vol.% and without CO and CO2.

Solid-state membrane module

DOEpatents

Gordon, John Howard [Salt Lake City, UT; Taylor, Dale M [Murray, UT

2011-06-07

Solid-state membrane modules comprising at least one membrane unit, where the membrane unit has a dense mixed conducting oxide layer, and at least one conduit or manifold wherein the conduit or manifold comprises a dense layer and at least one of a porous layer and a slotted layer contiguous with the dense layer. The solid-state membrane modules may be used to carry out a variety of processes including the separating of any ionizable component from a feedstream wherein such ionizable component is capable of being transported through a dense mixed conducting oxide layer of the membrane units making up the membrane modules. For ease of construction, the membrane units may be planar.

Hydrogen assisted cracking and CO2 corrosion behaviors of low-alloy steel with high strength used for armor layer of flexible pipe

NASA Astrophysics Data System (ADS)

Liu, Zhenguang; Gao, Xiuhua; Du, Linxiu; Li, Jianping; Zhou, Xiaowei; Wang, Xiaonan; Wang, Yuxin; Liu, Chuan; Xu, Guoxiang; Misra, R. D. K.

2018-05-01

In this study, hydrogen induced cracking (HIC), sulfide stress corrosion cracking (SSCC) and hydrogen embrittlement (HE) were carried out to study hydrogen assisted cracking behavior (HIC, SSCC and HE) of high strength pipeline steel used for armor layer of flexible pipe in ocean. The CO2 corrosion behavior of designed steel with high strength was studied by using immersion experiment. The experimental results demonstrate that the corrosion resistance of designed steel with tempered martensite to HIC, SSCC and HE is excellent according to specific standards, which contributes to the low concentration of dislocation and vacancies previously formed in cold rolling process. The corrosion mechanism of hydrogen induced cracking of designed steel, which involves in producing process, microstructure and cracking behavior, is proposed. The designed steel with tempered martensite shows excellent corrosion resistance to CO2 corrosion. Cr-rich compound was first formed on the coupon surface exposed to CO2-saturated brine condition and chlorine, one of the corrosion ions in solution, was rich in the inner layer of corrosion products.

Hydrogenation behavior of Ti-implanted Zr-1Nb alloy with TiN films deposited using filtered vacuum arc and magnetron sputtering

NASA Astrophysics Data System (ADS)

Kashkarov, E. B.; Nikitenkov, N. N.; Sutygina, A. N.; Bezmaternykh, A. O.; Kudiiarov, V. N.; Syrtanov, M. S.; Pryamushko, T. S.

2018-02-01

More than 60 years of operation of water-cooled reactors have shown that local or general critical hydrogen concentration is one of the basic limiting criteria of zirconium-based fuel element claddings. During the coolant radiolysis, released hydrogen penetrates and accumulates in zirconium alloys. Hydrogenation of zirconium alloys leads to degradation of their mechanical properties, hydride cracking and stress corrosion cracking. In this research the effect of titanium nitride (TiN) deposition on hydrogenation behavior of Ti-implanted Zr-1Nb alloy was described. Ti-implanted interlayer was fabricated by plasma immersion ion implantation (PIII) at the pulsed bias voltage of 1500 V to improve the adhesion of TiN and reduce hydrogen penetration into Zr-1Nb alloy. We conducted the comparative analysis on hydrogenation behavior of the Ti-implanted alloy with sputtered and evaporated TiN films by reactive dc magnetron sputtering (dcMS) and filtered cathodic vacuum arc deposition (FVAD), respectively. The crystalline structure and surface morphology were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The elemental distribution was analyzed using glow-discharge optical emission spectroscopy (GD-OES). Hydrogenation was performed from gas atmosphere at 350 °C and 2 atm hydrogen pressure. The results revealed that TiN films as well as Ti implantation significantly reduce hydrogen absorption rate of Zr-1Nb alloy. The best performance to reduce the rate of hydrogen absorption is Ti-implanted layer with evaporated TiN film. Morphology of the films impacted hydrogen permeation through TiN films: the denser film the lower hydrogen permeation. The Ti-implanted interface plays an important role of hydrogen accumulation layer for trapping the penetrated hydrogen. No deterioration of adhesive properties of TiN films on Zr-1Nb alloy with Ti-implanted interface occurs under high-temperature hydrogen exposure. Thus, the fabrication of Ti-implanted layer with dense TiN films can be an effective way to protect Zr-1Nb alloy from hydrogen embrittlement.

Importance of interlayer H bonding structure to the stability of layered minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conroy, Michele; Soltis, Jennifer A.; Wittman, Rick S.

2017-10-16

The exact atomic structures of layered minerals have been difficult to characterize because the layers often possess out-of-plane hydrogen atoms that cannot be detected by many analytical techniques. However, the ordering of these bonds are thought to play a fundamental role in the structural stability and solubility of layered minerals. We report a new strategy of using the intense radiation field of a focused electron beam to probe the effect of differences in hydrogen bonding networks on mineral solubility while simultaneously imaging the dissolution behavior in real time via liquid cell electron microscopy. We show the loss in hydrogens frommore » interlayers of boehmite (γ-AlOOH) resulted in 2D nanosheets exfoliating from the bulk that subsequently and rapidly dissolved. However gibbsite (γ-Al(OH)3), with its higher concentration of OH terminating groups, was more accommodating to the deprotonation and stable under the beam.« less

Evaluation and simultaneous optimization of bio-hydrogen production using 3 2 factorial design and the desirability function

NASA Astrophysics Data System (ADS)

Cuetos, M. J.; Gómez, X.; Escapa, A.; Morán, A.

Various mixtures incorporating a simulated organic fraction of municipal solid wastes and blood from a poultry slaughterhouse were used as substrate in a dark fermentation process for the production of hydrogen. The individual and interactive effects of hydraulic retention time (HRT), solid content in the feed (%TS) and proportion of residues (%Blood) on bio-hydrogen production were studied in this work. A central composite design and response surface methodology were employed to determine the optimum conditions for the hydrogen production process. Experimental results were approximated to a second-order model with the principal effects of the three factors considered being statistically significant (P < 0.05). The production of hydrogen obtained from the experimental point at conditions close to best operability was 0.97 L Lr -1 day -1. Moreover, a desirability function was employed in order to optimize the process when a second, methanogenic, phase is coupled with it. In this last case, the optimum conditions lead to a reduction in the production of hydrogen when the optimization process involves the maximization of intermediary products.

New solid state forms of antineoplastic 5-fluorouracil with anthelmintic piperazine

NASA Astrophysics Data System (ADS)

Moisescu-Goia, C.; Muresan-Pop, M.; Simon, V.

2017-12-01

The aim of the present study was to asses the formation of solid forms between the 5-fluorouracil chemotherapy drug and the anthelmintic piperazine. Two new solid forms of antineoplastic agent 5-fluorouracil with anthelmintic piperazine were obtained by liquid assisted ball milling and slurry crystallization methods. The Nsbnd H hydrogen bonding donors and C = O hydrogen bonding acceptors of 5-fluorouracil allow to form co-crystals with other drugs delivering improved properties for medical applications, as proved for other compounds of pharmaceutical interest. Both new solid forms were investigated using X-ray powder diffraction (XRD), differential thermal analysis (DTA) and Fourier transform infrared (FTIR) spectroscopy. The XRD results show that by both methods were successfully synthesized new solid forms of 5-fluorouracil with piperazine. According to FTIR results the form prepared by lichid assisted grinding process was obtained as co-crystal and the other one, prepared by slurry method, resulted as a salt.

Sequential desorption energy of hydrogen from nickel clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deepika,; Kumar, Rakesh, E-mail: rakesh@iitrpr.ac.in; R, Kamal Raj.

2015-06-24

We report reversible Hydrogen adsorption on Nickel clusters, which act as a catalyst for solid state storage of Hydrogen on a substrate. First-principles technique is employed to investigate the maximum number of chemically adsorbed Hydrogen molecules on Nickel cluster. We observe a maximum of four Hydrogen molecules adsorbed per Nickel atom, but the average Hydrogen molecules adsorbed per Nickel atom decrease with cluster size. The dissociative chemisorption energy per Hydrogen molecule and sequential desorption energy per Hydrogen atom on Nickel cluster is found to decrease with number of adsorbed Hydrogen molecules, which on optimization may help in economical storage andmore » regeneration of Hydrogen as a clean energy carrier.« less

Key study on the potential of hydrazine bisborane for solid- and liquid-state chemical hydrogen storage.

PubMed

Pylypko, Sergii; Petit, Eddy; Yot, Pascal G; Salles, Fabrice; Cretin, Marc; Miele, Philippe; Demirci, Umit B

2015-05-04

Hydrazine bisborane N2H4(BH3)2 (HBB; 16.8 wt %) recently re-emerged as a potential hydrogen storage material. However, such potential is controversial: HBB was seen as a hazardous compound up to 2010, but now it would be suitable for hydrogen storage. In this context, we focused on fundamentals of HBB because they are missing in the literature and should help to shed light on its effective potential while taking into consideration any risk. Experimental/computational methods were used to get a complete characterization data sheet, including, e.g., XRD, NMR, FTIR, Raman, TGA, and DSC. From the reported results and discussion, it is concluded that HBB has potential in the field of chemical hydrogen storage given that both thermolytic and hydrolytic dehydrogenations were analyzed. In solid-state chemical hydrogen storage, it cannot be used in the pristine state (risk of explosion during dehydrogenation) but can be used for the synthesis of derivatives with improved dehydrogenation properties. In liquid-state chemical hydrogen storage, it can be studied for room-temperature dehydrogenation, but this requires the development of an active and selective metal-based catalyst. HBB is a thus a candidate for chemical hydrogen storage.

Formation of Nitrogen and Hydrogen-bearing Molecules in Solid Ammonia and Implications for Solar System and Interstellar Ices

NASA Astrophysics Data System (ADS)

Zheng, Weijun; Jewitt, David; Osamura, Yoshihiro; Kaiser, Ralf I.

2008-02-01

We irradiated solid ammonia (NH3) in the temperature range of 10-60 K with high-energy electrons to simulate the processing of ammonia-bearing ices in the interstellar medium and in the solar system. By monitoring the newly formed molecules online and in situ, the synthesis of hydrazine (N2H4), diazene (N2H2 isomers), hydrogen azide (HN3), the amino radical (NH2), molecular hydrogen (H2), and molecular nitrogen (N2) has been confirmed. Our results show that the production rates of hydrazine, diazene, hydrogen azide, molecular hydrogen, and molecular nitrogen are higher in amorphous ammonia than those in crystalline ammonia; this behavior is similar to the production of molecular hydrogen, molecular oxygen, and hydrogen peroxide found in electron-irradiated water ices. However, the formation of hydrazine in crystalline ammonia does not show any temperature dependence. Our experimental results give hints to the origin of molecular nitrogen in the Saturnian system and possibly in the atmospheres of proto-Earth and Titan; our research may also guide the search of hitherto unobserved nitrogen-bearing molecules in the interstellar medium and in our solar system.

Solid-state membrane module

DOEpatents

Hinklin, Thomas Ray; Lewinsohn, Charles Arthur

2015-06-30

A module for separating oxygen from an oxygen-containing gaseous mixture comprising planar solid-state membrane units, each membrane unit comprising planar dense mixed conducting oxides layers, planar channel-free porous support layers, and one or more planar intermediate support layers comprising at least one channeled porous support layer. The porosity of the planar channeled porous support layers is less than the porosity of the planar channel-free porous support layers.

An Overview of Natural Gas Conversion Technologies for Co-Production of Hydrogen and Value-Added Solid Carbon Products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagle, Robert A.; Dagle, Vanessa; Bearden, Mark D.

This report was prepared in response to the U.S. Department of Energy Fuel Cell Technologies Office Congressional Appropriation language to support research on carbon-free production of hydrogen using new chemical processes that utilize natural gas to produce solid carbon and hydrogen. The U.S. produces 9-10 million tons of hydrogen annually with more than 95% of the hydrogen produced by steam-methane reforming (SMR) of natural gas. SMR is attractive because of its high hydrogen yield; but it also converts the carbon to carbon dioxide. Non-oxidative thermal decomposition of methane to carbon and hydrogen is an alternative to SMR and produces COmore » 2-free hydrogen. The produced carbon can be sold as a co-product, thus providing economic credit that reduces the delivered net cost of hydrogen. The combination of producing hydrogen with potentially valuable carbon byproducts has market value in that this allows greater flexibility to match the market prices of hydrogen and carbon. That is, the higher value product can subsidize the other in pricing decisions. In this report we highlight the relevant technologies reported in the literature—primarily thermochemical and plasma conversion processes—and recent research progress and commercial activities. Longstanding technical challenges include the high energetic requirements (e.g., high temperatures and/or electricity requirements) necessary for methane activation and, for some catalytic processes, the separation of solid carbon product from the spent catalyst. We assess current and new carbon product markets that could be served given technological advances, and we discuss technical barriers and potential areas of research to address these needs. We provide preliminary economic analysis for these processes and compare to other emerging (e.g., electrolysis) and conventional (e.g., SMR) processes for hydrogen production. The overarching conclusion of this study is that the cost of hydrogen can be potentially reduced to target levels of $2/kg with the co-production and sale of a sufficiently high-value carbon product. Technological advances are required to understand the reaction conditions and design reactor systems that can achieve high yields of the select carbon products and segregate or separate the high-value carbon products, and optimize the production process for both hydrogen and carbon.« less

Pulsed laser vaporization synthesis of boron loaded few layered graphene (Conference Presentation)

NASA Astrophysics Data System (ADS)

Tennyson, Wesley D.; Tian, Mengkun; More, Karren L.; Geohegan, David B.; Puretzky, Alexander A.; Papandrew, Alexander B.; Rouleau, Christopher M.; Yoon, Mina

2017-02-01

The bulk production of loose graphene flakes and its doped variants are important for energy applications including batteries, fuel cells, and supercapacitors as well as optoelectronic and thermal applications. While laser-based methods have been reported for large-scale synthesis of single-wall carbon nanohorns (SWNHs), similar large-scale production of graphene has not been reported. Here we explored the synthesis of doped few layered graphene by pulsed laser vaporization (PLV) with the goal of producing an oxidation resistant electrode support for solid acid fuel cells. PLV of graphite with various amounts of boron was carried out in mixtures in either Ar or Ar/H2 at 0.1 MPa at elevated temperatures under conditions typically used for synthesis of SWNHs. Both the addition of hydrogen to the background argon, or the addition of boron to the carbon target, was found to shift the formation of carbon nanohorns to two-dimensional flakes of a new form of few-layer graphene material, with sizes up to microns in dimension as confirmed by XRD and TEM. However, the materials made with boron exhibited superior resistance to carbon corrosion in the solid acid fuel cell and thermal oxidation resistance in air compared to similar product made without boron. Mechanisms for the synthesis and oxidation resistance of these materials will be discussed based upon detailed characterization and modeling. •Synthesis science was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. Material processing and characterization science supported by ARPA-E under Cooperative Agreement Number DE-AR0000499 and as a user project at the Center for Nanophase Materials Sciences, a Department of Energy Office of Science User Facility.

The effect of surface oxide layer on the rate of hydrogen emission from aluminum and its alloys in a high vacuum

NASA Technical Reports Server (NTRS)

Makarova, V. I.; Zyabrev, A. A.

1979-01-01

The influence of surface oxide layers on the kinetics of hydrogen emission at the high vacuum of 10 to the minus 8th power torr was investigated at temperatures from 20 to 450 C using samples of pure AB00 aluminum and the cast alloy AMg. Cast and deformed samples of AMts alloy were used to study the effect of oxide film thickness on the rate of hydrogen emission. Thermodynamic calculations of the reactions of the generation and dissociation of aluminum oxide show that degasification at elevated temperatures (up to 600 C) and high vacuum will not reduce the thickness of artificially-generated surface oxide layers on aluminum and its alloys.

A two-dimensional hydrogen-bonded water layer in the structure of a cobalt(III) cubane complex.

PubMed

Qi, Ji; Zhai, Xiang-Sheng; Zhu, Hong-Lin; Lin, Jian-Li

2014-02-01

A tetranuclear Co(III) oxide complex with cubane topology, tetrakis(2,2'-bipyridine-κ(2)N,N')di-μ2-carbonato-κ(4)O:O'-tetra-μ3-oxido-tetracobalt(III) pentadecahydrate, [Co4(CO3)2O4(C10H8N2)4]·15H2O, with an unbounded hydrogen-bonded water layer, has been synthesized by reaction of CoCO3 and 2,2'-bipyridine. The solvent water molecules form a hydrogen-bonded net with tetrameric and pentameric water clusters as subunits. The Co4O4 cubane-like cores are sandwiched between the water layers, which are further stacked into a three-dimensional metallo-supramolecular network.

Effect of Mass Proportion of Municipal Solid Waste Incinerator Bottom Ash Layer to Municipal Solid Waste Layer on the Cu and Zn Discharge from Landfill.

PubMed

Kong, Qingna; Yao, Jun; Qiu, Zhanhong; Shen, Dongsheng

2016-01-01

Municipal solid waste incinerator (MSWI) bottom ash is often used as the protection layer for the geomembrane and intermediate layer in the landfill. In this study, three sets of simulated landfills with different mass proportion of MSWI bottom ash layer to municipal solid waste (MSW) layer were operated. Cu and Zn concentrations in the leachates and MSW were monitored to investigate the effect of MSWI bottom ash layer on the Cu and Zn discharge from the landfill. The results showed that the Zn discharge was dependent on the mass proportion of MSWI bottom ash layer. The pH of landfill was not notably increased when the mass proportion of MSWI bottom ash layer to MSW layer was 1 : 9, resulting in the enhancement of the Zn discharge. However, Zn discharge was mitigated when the mass proportion was 2 : 8, as the pH of landfill was notably promoted. The discharge of Cu was not dependent on the mass proportion, due to the great affinity of Cu to organic matter. Moreover, Cu and Zn contents of the sub-MSW layer increased due to the MSWI bottom ash layer. Therefore, the MSWI bottom ash layer can increase the potential environmental threat of the landfill.

Method of controllong the deposition of hydrogenated amorphous silicon and apparatus therefor

DOEpatents

Hanak, Joseph J.

1985-06-25

An improved method and apparatus for the controlled deposition of a layer of hydrogenated amorphous silicon on a substrate. Means is provided for the illumination of the coated surface of the substrate and measurement of the resulting photovoltage at the outermost layer of the coating. Means is further provided for admixing amounts of p type and n type dopants to the reactant gas in response to the measured photovoltage to achieve a desired level and type of doping of the deposited layer.

Quinary wurtzite Zn-Ga-Ge-N-O solid solutions and their photocatalytic properties under visible light irradiation

PubMed Central

Xie, Yinghao; Wu, Fangfang; Sun, Xiaoqin; Chen, Hongmei; Lv, Meilin; Ni, Shuang; Liu, Gang; Xu, Xiaoxiang

2016-01-01

Wurtzite solid solutions between GaN and ZnO highlight an intriguing paradigm for water splitting into hydrogen and oxygen using solar energy. However, large composition discrepancy often occurs inside the compound owing to the volatile nature of Zn, thereby prescribing rigorous terms on synthetic conditions. Here we demonstrate the merits of constituting quinary Zn-Ga-Ge-N-O solid solutions by introducing Ge into the wurtzite framework. The presence of Ge not only mitigates the vaporization of Zn but also strongly promotes particle crystallization. Synthetic details for these quinary compounds were systematically explored and their photocatalytic properties were thoroughly investigated. Proper starting molar ratios of Zn/Ga/Ge are of primary importance for single phase formation, high particle crystallinity and good photocatalytic performance. Efficient photocatalytic hydrogen and oxygen production from water were achieved for these quinary solid solutions which is strongly correlated with Ge content in the structure. Apparent quantum efficiency for optimized sample approaches 1.01% for hydrogen production and 1.14% for oxygen production. Theoretical calculation reveals the critical role of Zn for the band gap reduction in these solid solutions and their superior photocatalytic acitivity can be understood by the preservation of Zn in the structure as well as a good crystallinity after introducing Ge. PMID:26755070

Quinary wurtzite Zn-Ga-Ge-N-O solid solutions and their photocatalytic properties under visible light irradiation.

PubMed

Xie, Yinghao; Wu, Fangfang; Sun, Xiaoqin; Chen, Hongmei; Lv, Meilin; Ni, Shuang; Liu, Gang; Xu, Xiaoxiang

2016-01-12

Wurtzite solid solutions between GaN and ZnO highlight an intriguing paradigm for water splitting into hydrogen and oxygen using solar energy. However, large composition discrepancy often occurs inside the compound owing to the volatile nature of Zn, thereby prescribing rigorous terms on synthetic conditions. Here we demonstrate the merits of constituting quinary Zn-Ga-Ge-N-O solid solutions by introducing Ge into the wurtzite framework. The presence of Ge not only mitigates the vaporization of Zn but also strongly promotes particle crystallization. Synthetic details for these quinary compounds were systematically explored and their photocatalytic properties were thoroughly investigated. Proper starting molar ratios of Zn/Ga/Ge are of primary importance for single phase formation, high particle crystallinity and good photocatalytic performance. Efficient photocatalytic hydrogen and oxygen production from water were achieved for these quinary solid solutions which is strongly correlated with Ge content in the structure. Apparent quantum efficiency for optimized sample approaches 1.01% for hydrogen production and 1.14% for oxygen production. Theoretical calculation reveals the critical role of Zn for the band gap reduction in these solid solutions and their superior photocatalytic acitivity can be understood by the preservation of Zn in the structure as well as a good crystallinity after introducing Ge.

Quinary wurtzite Zn-Ga-Ge-N-O solid solutions and their photocatalytic properties under visible light irradiation

NASA Astrophysics Data System (ADS)

Xie, Yinghao; Wu, Fangfang; Sun, Xiaoqin; Chen, Hongmei; Lv, Meilin; Ni, Shuang; Liu, Gang; Xu, Xiaoxiang

2016-01-01

Wurtzite solid solutions between GaN and ZnO highlight an intriguing paradigm for water splitting into hydrogen and oxygen using solar energy. However, large composition discrepancy often occurs inside the compound owing to the volatile nature of Zn, thereby prescribing rigorous terms on synthetic conditions. Here we demonstrate the merits of constituting quinary Zn-Ga-Ge-N-O solid solutions by introducing Ge into the wurtzite framework. The presence of Ge not only mitigates the vaporization of Zn but also strongly promotes particle crystallization. Synthetic details for these quinary compounds were systematically explored and their photocatalytic properties were thoroughly investigated. Proper starting molar ratios of Zn/Ga/Ge are of primary importance for single phase formation, high particle crystallinity and good photocatalytic performance. Efficient photocatalytic hydrogen and oxygen production from water were achieved for these quinary solid solutions which is strongly correlated with Ge content in the structure. Apparent quantum efficiency for optimized sample approaches 1.01% for hydrogen production and 1.14% for oxygen production. Theoretical calculation reveals the critical role of Zn for the band gap reduction in these solid solutions and their superior photocatalytic acitivity can be understood by the preservation of Zn in the structure as well as a good crystallinity after introducing Ge.

Advantages of InGaN/GaN multiple quantum wells with two-step grown low temperature GaN cap layers

NASA Astrophysics Data System (ADS)

Zhu, Yadan; Lu, Taiping; Zhou, Xiaorun; Zhao, Guangzhou; Dong, Hailiang; Jia, Zhigang; Liu, Xuguang; Xu, Bingshe

2017-11-01

Two-step grown low temperature GaN cap layers (LT-cap) are employed to improve the optical and structural properties of InGaN/GaN multiple quantum wells (MQWs). The first LT-cap layer is grown in nitrogen atmosphere, while a small hydrogen flow is added to the carrier gas during the growth of the second LT-cap layer. High-resolution X-ray diffraction results indicate that the two-step growth method can improve the interface quality of MQWs. Room temperature photoluminescence (PL) tests show about two-fold enhancement in integrated PL intensity, only 25 meV blue-shift in peak energy and almost unchanged line width. On the basis of temperature-dependent PL characteristics analysis, it is concluded that the first and the second LT-cap layer play a different role during the growth of MQWs. The first LT-cap layer acts as a protective layer, which protects quantum well from serious indium loss and interface roughening resulting from the hydrogen over-etching. The hydrogen gas employed in the second LT-cap layer is in favor of reducing defect density and indium segregation. Consequently, interface/surface and optical properties are improved by adopting the two-step growth method.

C sbnd H…F hydrogen bonds as the organising force in F-substituted α-phenyl cinnamic acid aggregates studied by the combination of FTIR spectroscopy and computations

NASA Astrophysics Data System (ADS)

Tolnai, B.; Kiss, J. T.; Felföldi, K.; Pálinkó, I.

2009-04-01

Various F-substituted E-2,3-diphenyl propenoic acid molecules were synthesised and their aggregation behaviour was studied by experimental (FT-IR spectroscopy) and computational (semiempirical and DFT) methods. Experimental approach embraced the identification of potential hydrogen bonding sites through finding the relevant IR bands and monitoring their shifts upon increasing the acid concentration and on going to the solid state. It was found that fluorine engaged in C sbnd H…F hydrogen bonding easily, where the carbon atom could be of any kind available in the molecule (aromatic, aliphatic or olefinic). Shifts were found even in moderately concentrated solutions and in the solid state too. Hydrogen bonding sites could be assigned and relevant aggregate models could be built. Molecular modelling allowed obtaining good estimates for hydrogen bond lengths and angles and visualisation of the geometric arrangements even of extended networks also became feasible.

Improving the photovoltaic performance of the all-solid-state TiO2 NR/CuInS2 solar cell by hydrogen plasma treatment.

PubMed

Chen, Bingfeng; Niu, Wenzhe; Lou, Zirui; Ye, Zhizhen; Zhu, Liping

2018-07-06

The interfacial properties of the heterojunction between p-type and n-type materials play an important role in the performance of the solar cell. In this paper, a p-type CuInS 2 film was deposited on TiO 2 nanorod arrays by spin coating to fabricate an all-solid-state solar cell and the TiO 2 nanorod arrays were treated with hydrogen plasma(H:TiO 2 ) to ameliorate the interfacial properties. The influence of the hydrogen plasma treatment on the performance of the solar cell was investigated. The short-circuit current density was obviously raised and the power conversion efficiency of the solar cell improved to 0.30%, which is three times that of solar cells without hydrogen plasma treatment. The enhancement of the performance is attributed to not only the enhancement of carrier separation and transport, but the reduction of the recombination of electrons and holes, which is caused by hydrogen plasma treatment.

Improving the photovoltaic performance of the all-solid-state TiO2 NR/CuInS2 solar cell by hydrogen plasma treatment

NASA Astrophysics Data System (ADS)

Chen, Bingfeng; Niu, Wenzhe; Lou, Zirui; Ye, Zhizhen; Zhu, Liping

2018-07-01

The interfacial properties of the heterojunction between p-type and n-type materials play an important role in the performance of the solar cell. In this paper, a p-type CuInS2 film was deposited on TiO2 nanorod arrays by spin coating to fabricate an all-solid-state solar cell and the TiO2 nanorod arrays were treated with hydrogen plasma(H:TiO2) to ameliorate the interfacial properties. The influence of the hydrogen plasma treatment on the performance of the solar cell was investigated. The short-circuit current density was obviously raised and the power conversion efficiency of the solar cell improved to 0.30%, which is three times that of solar cells without hydrogen plasma treatment. The enhancement of the performance is attributed to not only the enhancement of carrier separation and transport, but the reduction of the recombination of electrons and holes, which is caused by hydrogen plasma treatment.

Quantum Monte Carlo study of the phase diagram of solid molecular hydrogen at extreme pressures

PubMed Central

Drummond, N. D.; Monserrat, Bartomeu; Lloyd-Williams, Jonathan H.; Ríos, P. López; Pickard, Chris J.; Needs, R. J.

2015-01-01

Establishing the phase diagram of hydrogen is a major challenge for experimental and theoretical physics. Experiment alone cannot establish the atomic structure of solid hydrogen at high pressure, because hydrogen scatters X-rays only weakly. Instead, our understanding of the atomic structure is largely based on density functional theory (DFT). By comparing Raman spectra for low-energy structures found in DFT searches with experimental spectra, candidate atomic structures have been identified for each experimentally observed phase. Unfortunately, DFT predicts a metallic structure to be energetically favoured at a broad range of pressures up to 400 GPa, where it is known experimentally that hydrogen is non-metallic. Here we show that more advanced theoretical methods (diffusion quantum Monte Carlo calculations) find the metallic structure to be uncompetitive, and predict a phase diagram in reasonable agreement with experiment. This greatly strengthens the claim that the candidate atomic structures accurately model the experimentally observed phases. PMID:26215251

H-Coal process and plant design

DOEpatents

Kydd, Paul H.; Chervenak, Michael C.; DeVaux, George R.

1983-01-01

A process for converting coal and other hydrocarbonaceous materials into useful and more valuable liquid products. The process comprises: feeding coal and/or other hydrocarbonaceous materials with a hydrogen-containing gas into an ebullated catalyst bed reactor; passing the reaction products from the reactor to a hot separator where the vaporous and distillate products are separated from the residuals; introducing the vaporous and distillate products from the separator directly into a hydrotreater where they are further hydrogenated; passing the residuals from the separator successively through flash vessels at reduced pressures where distillates are flashed off and combined with the vaporous and distillate products to be hydrogenated; transferring the unseparated residuals to a solids concentrating and removal means to remove a substantial portion of solids therefrom and recycling the remaining residual oil to the reactor; and passing the hydrogenated vaporous and distillate products to an atmospheric fractionator where the combined products are fractionated into separate valuable liquid products. The hydrogen-containing gas is generated from sources within the process.

METHOD OF COMBINING HYDROGEN AND OXYGEN

DOEpatents

McBride, J.P.

1962-02-27

A method is given for the catalytic recombination of radiolytic hydrogen and/or deulerium and oxygen resulting from the subjection or an aqueous thorium oxide or thorium oxide-uranium oxide slurry to ionizing radiation. An improved catalyst is prepared by providing paliadium nitrate in an aqueous thorium oxide sol at a concentration of at least 0.05 grams per gram of thorium oxide and contacting the sol with gaseous hydrogen to form flocculated solids. The solids are then recovered and added to the slurry to provide a palladium concentration of 100 to 1000 parts per million. Recombination is effected by the calalyst at a rate sufficient to support high nuclear reactor power densities. (AEC)

Dipolar induced para-hydrogen-induced polarization.

PubMed

Buntkowsky, Gerd; Gutmann, Torsten; Petrova, Marina V; Ivanov, Konstantin L; Bommerich, Ute; Plaumann, Markus; Bernarding, Johannes

2014-01-01

Analytical expressions for the signal enhancement in solid-state PHIP NMR spectroscopy mediated by homonuclear dipolar interactions and single pulse or spin-echo excitation are developed and simulated numerically. It is shown that an efficient enhancement of the proton NMR signal in solid-state NMR studies of chemisorbed hydrogen on surfaces is possible. Employing typical reaction efficacy, enhancement-factors of ca. 30-40 can be expected both under ALTADENA and under PASADENA conditions. This result has important consequences for the practical application of the method, since it potentially allows the design of an in-situ flow setup, where the para-hydrogen is adsorbed and desorbed from catalyst surfaces inside the NMR magnet. Copyright © 2014 Elsevier Inc. All rights reserved.

Measurement of backbone hydrogen-deuterium exchange in the type III secretion system needle protein PrgI by solid-state NMR

NASA Astrophysics Data System (ADS)

Chevelkov, Veniamin; Giller, Karin; Becker, Stefan; Lange, Adam

2017-10-01

In this report we present site-specific measurements of amide hydrogen-deuterium exchange rates in a protein in the solid state phase by MAS NMR. Employing perdeuteration, proton detection and a high external magnetic field we could adopt the highly efficient Relax-EXSY protocol previously developed for liquid state NMR. According to this method, we measured the contribution of hydrogen exchange on apparent 15N longitudinal relaxation rates in samples with differing D2O buffer content. Differences in the apparent T1 times allowed us to derive exchange rates for multiple residues in the type III secretion system needle protein.

Hydrogen sorption characteristics of nanostructured Pd–10Rh processed by cryomilling

DOE PAGES

Yang, Nancy; Yee, Joshua K.; Zhang, Zhihui; ...

2014-10-03

Palladium and its alloys are model systems for studying solid-state storage of hydrogen. Mechanical milling is commonly used to process complex powder systems for solid-state hydrogen storage; however, milling can also be used to evolve nanostructured powder to modify hydrogen sorption characteristics. In the present study, cryomilling (mechanical attrition milling in a cryogenic liquid) is used to produce nanostructured palladium-rhodium alloy powder. Characterization of the cryomilled Pd-10Rh using electron microscopy, X-ray diffraction, and surface area analysis reveals that (i) particle morphology evolves from spherical to flattened disk-like particles; while the (ii) crystallite size decreases from several microns to less thanmore » 100 nm and (iii) dislocation density increases with increased cryomilling time. Hydrogen absorption and desorption isotherms as well as the time scales for absorption were measured for cryomilled Pd-10Rh, and correlated with observed microstructural changes induced by the cryomilling process. In short, as the microstructure of the Pd-10Rh alloy is refined by cryomilling: (i) the maximum hydrogen concentration in the α-phase increases, (ii) the pressure plateau becomes flatter, and (iii) the equilibrium hydrogen capacity at 760 Torr increases. In addition, the rate of hydrogen absorption was reduced by an order of magnitude compared to non-cryomilled (atomized) powder.« less

Origin of the OH vibrational blue shift in the LiOH crystal.

PubMed

Hermansson, Kersti; Gajewski, Grzegorz; Mitev, Pavlin D

2008-12-25

The O-H vibrational frequency in crystalline hydroxides is either upshifted or downshifted by its crystalline surroundings. In the LiOH crystal, the experimental gas-to-solid O-H frequency upshift ("blue shift") is approximately +115 cm(-1). Here plane-wave DFT calculations for the isotope-isolated LiOH crystal have been performed and we discuss the origin of the OH frequency upshift, and the nature of the OH group and the interlayer interactions. We find that (1) the vibrational frequency upshift originates from interactions within the LiOH layer; this OH upshift is slightly lessened by the interlayer interactions; (2) the interlayer O-H - - - H-O interaction is largely electrostatic in character (but there is no hydrogen bonding); (3) the gas-to-solid vibrational shift for OH in LiOH(s) and its subsystems qualitatively adheres to a parabola-like "frequency vs electric field strength" correlation curve, which has a maximum for a positive electric field, akin to the correlation curve earlier found in the literature for an isolated OH(-) ion in an electric field.

Influence of anode thickness on the power output of solid oxide fuel cells with (La,Sr)(Co,Fe)-type cathode

NASA Astrophysics Data System (ADS)

Menzler, Norbert H.; Haanappel, Vincent A. C.

The influence of the thickness of the anode (functional layer) on the power output of anode-supported solid oxide fuel cells with a lanthanum-strontium-cobalt-ferrite cathode was investigated. The anode was applied by vacuum slip casting and the thickness varied between 1 and 22 μm. All other material and microstructural parameters were kept constant. Single cells with dimensions of 50 mm × 50 mm and with an active cathode area of 40 mm × 40 mm were manufactured and tested in an alumina housing with air as oxidant and hydrogen with 3% water vapour as the fuel gas. Results have shown that SOFCs with anodes between 1 and 13 μm have slightly better performance than those with thicker anodes (∼1.7 A cm -2 versus 1.5 A cm -2 at 800 °C and 0.7 V). The current densities were discussed with respect to cell area specific resistance, helium leak rate of the half-cell, and microstructure.

Mechanical properties of turbine blade alloys in hydrogen at elevated temperatures

NASA Technical Reports Server (NTRS)

Deluca, D. P.

1981-01-01

The mechanical properties of single crystal turbine blade alloys in a gaseous hydrogen environment were determined. These alloys are proposed for use in space propulsion systems in pure or partial high pressure hydrogen environments at elevated temperatures. Mechanical property tests included: tensile, creep, low fatigue (LCF), and crack growth. Specimens were in both transverse and longitudinal directions relative to the casting solidification direction. Testing was conducted on solid specimens exposed to externally pressurized environments of gaseous hydrogen and hydrogen-enriched steam.

Multi-layered proton-conducting electrolyte

DOEpatents

Lee, Tae H.; Dorris, Stephen E.; Balachandran, Uthamalingam

2017-06-27

The present invention provides a multilayer anode/electrolyte assembly comprising a porous anode substrate and a layered solid electrolyte in contact therewith. The layered solid electrolyte includes a first dense layer of yttrium-doped barium zirconate (BZY), optionally including another metal besides Y, Ba, and Zr (e.g., a lanthanide metal such as Pr) on one surface thereof, a second dense layer of yttrium-doped barium cerate (BCY), and an interfacial layer between and contacting the BZY and BCY layers. The interfacial layer comprises a solid solution of the BZY and BCY electrolytes. The porous anode substrate comprises at least one porous ceramic material that is stable to carbon dioxide and water (e.g., porous BZY), as well as an electrically conductive metal and/or metal oxide (e.g., Ni, NiO, and the like).

Origin of hydrogen-inclusion-induced critical current deviation in Nb/AlOx/Al/Nb Josephson junctions

NASA Astrophysics Data System (ADS)

Hinode, Kenji; Satoh, Tetsuro; Nagasawa, Shuichi; Hidaka, Mutsuo

2010-04-01

We investigated the mechanisms that change the critical current density (Jc) of Nb/AlOx/Al/Nb Josephson junctions due to the inclusion of hydrogen in the Nb electrodes. Our investigations were performed according to three aspects: the superconductivity change, the change in thickness of the barrier layer, and the change in the barrier height due to the electronic effect. The results are as follows: (a) the hydrogen-inclusion-accompanied changes in the superconductivity parameters, such as the junction gap voltage, were much less than those of the critical current density, (b) the effect of hydrogen inclusion on Jc varied depending on the electrodes, i.e., the upper electrode above the barrier layer was the most affected, (c) the junctions with increased Ics due to hydrogen exclusion showed the identical amount of decrease in the junction resistance measured at room temperature, and (d) the hydrogen exclusion from the junction electrodes had no influence on the Nb/Al/AlOx/Al/Nb junctions, which had an extra Al layer. Based on these results we conclude that the Jc change is mainly caused by the change in junction resistance. A one order of magnitude smaller effect is caused by the superconductivity change. We believe the Jc change is caused by a Nb work function increase due to the hydrogen inclusion, resulting in an increase in barrier height.

Uniform Atomic Layer Deposition of Al2O3 on Graphene by Reversible Hydrogen Plasma Functionalization

PubMed Central

2017-01-01

A novel method to form ultrathin, uniform Al2O3 layers on graphene using reversible hydrogen plasma functionalization followed by atomic layer deposition (ALD) is presented. ALD on pristine graphene is known to be a challenge due to the absence of dangling bonds, leading to nonuniform film coverage. We show that hydrogen plasma functionalization of graphene leads to uniform ALD of closed Al2O3 films down to 8 nm in thickness. Hall measurements and Raman spectroscopy reveal that the hydrogen plasma functionalization is reversible upon Al2O3 ALD and subsequent annealing at 400 °C and in this way does not deteriorate the graphene’s charge carrier mobility. This is in contrast with oxygen plasma functionalization, which can lead to a uniform 5 nm thick closed film, but which is not reversible and leads to a reduction of the charge carrier mobility. Density functional theory (DFT) calculations attribute the uniform growth on both H2 and O2 plasma functionalized graphene to the enhanced adsorption of trimethylaluminum (TMA) on these surfaces. A DFT analysis of the possible reaction pathways for TMA precursor adsorption on hydrogenated graphene predicts a binding mechanism that cleans off the hydrogen functionalities from the surface, which explains the observed reversibility of the hydrogen plasma functionalization upon Al2O3 ALD. PMID:28405059

Hydrogen adsorption site on the Ni?110?-p(1 × 2)-H surface from time-of-flight scattering and recoiling spectrometry (TOF-SARS)

NASA Astrophysics Data System (ADS)

Bu, H.; Roux, C. D.; Rabalais, J. W.

The adsorption site of hydrogen on the Ni{110}-p(1 × 2)-H surface resulting from saturation exposure to H 2 at ˜ 310-350 K has been investigated by time-of-flight scattering and recoiling spectrometry (TOF-SARS). The recoiled neutral plus ion hydrogen atom flux resulting from 2-5 keV Ar + or Ne + pulsed ion beams incident on the surface was monitored as a function of crystal azimuthal angle and beam incidence angle. From classical trajectory calculations and shadowing and blocking analyses, it is concluded that hydrogen atoms are localized at the pseudo-three-fold sites on the (1 × 2) missing-row (MR) reconstructed Ni{110} surface; the (1 × 2) MR reconstruction is induced by hydrogen adsorption shown elsewhere [Surf. Sci. 259 (1991) 253]. Only the pseudo-three-fold site is consistent with all of the experimental data. The coordinates of the hydrogen adsorption site with respect to the nickel lattice were determined. The lateral distance of hydrogen from the 1st-layer Ni <1 overline10> rows is 1.56 ± 0.12 Å and the vertical distance above the substrate is 0.21 ± 0.12 Å, providing NiH bond lengths of 2.0 Å to the two-layer Ni atoms and 1.5 Å to the 2nd-layer Ni atom.

Strain-tolerant ceramic coated seal

DOEpatents

Schienle, James L.; Strangman, Thomas E.

1994-01-01

A metallic regenerator seal is provided having multi-layer coating comprising a NiCrAlY bond layer, a yttria stabilized zirconia (YSZ) intermediate layer, and a ceramic high temperature solid lubricant surface layer comprising zinc oxide, calcium fluoride, and tin oxide. An array of discontinuous grooves is laser machined into the outer surface of the solid lubricant surface layer making the coating strain tolerant.

Stable catalyst layers for hydrogen permeable composite membranes

DOEpatents

Way, J. Douglas; Wolden, Colin A

2014-01-07

The present invention provides a hydrogen separation membrane based on nanoporous, composite metal carbide or metal sulfide coated membranes capable of high flux and permselectivity for hydrogen without platinum group metals. The present invention is capable of being operated over a broad temperature range, including at elevated temperatures, while maintaining hydrogen selectivity.

Association of 2-acylaminopyridines and benzoic acids. Steric and electronic substituent effect studied by XRD, solution and solid-state NMR and calculations

NASA Astrophysics Data System (ADS)

Ośmiałowski, Borys; Kolehmainen, Erkki; Ejsmont, Krzysztof; Ikonen, Satu; Valkonen, Arto; Rissanen, Kari; Nonappa

2013-12-01

Eight single crystal X-ray structures, solid-state NMR spectroscopic, and theoretical studies utilizing QTAIM methodology were used to characterize the 2-acyl (alkyl in acyl = methyl, ethyl, t-butyl, and 1-adamantyl) amino-6-R-pyridine/4-R‧-benzoic acid (R,R‧ = H or Me) cocrystals. As expected among alkyl groups 1-adamantyl due to its bulkiness has the most significant effect on the relative positions of molecules in cocrystals. In addition, the subtle electronic and steric effects by the methyl substituents were observed. The theoretical calculations with full geometry optimizations are in agreement with the experimental findings (geometry, energy of hydrogen bonds). Based on the crystal structures and calculations it is concluded that p-methyl substituent in benzoic acid increase the hydrogen bond accepting ability of the CO oxygen and decreases the hydrogen bond donating ability of OH proton. The 15N solid-state (CP MAS) NMR chemical shifts prove that molecules in cocrystal are held together by hydrogen bonding. The biggest variation in the 15N chemical shift of acylamino nitrogen can be related with the size of the alkyl group in acyl moiety.

New criteria to determine the destabilization of the acidogenic anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW) with mixed sludge (MS).

PubMed

Angeriz-Campoy, R; Fdez-Güelfo, L A; Tyagi, Vinay Kumar; Álvarez-Gallego, C J; Romero-García, L I

2018-01-01

Effect of hydraulic retention time (HRT) on bio-hydrogen production from co-digestion of organic fraction of municipal solid waste (OFMSW) and mixed sludge (MS) in dry thermophilic conditions (55°C and 20% total solids) was investigated. A decreasing sequence of six HRTs, from 2.9 to 0.8-days, was performed to evaluate the stability of the system and the influence of HRT on the organic matter solubilization, the daily hydrogen production (HP) and the specific hydrogen production (SHP). Best results were obtained operating at 1.2-days HRT: HP of 3.67L H 2 /L reactor /day, SHP of 33.8mL H 2 /gVS added and hydrogen percentage in biogas of 52.4%. However, HRTs lower than 1.2-days induce failure in the system due to an unbalance of the hydrolytic phase. This fact was corroborated through the evaluation of two indirect parameters, "non-solubilized carbon" (NSC) and "acidogenic substrate as carbon" (ASC), and the relationships of NSC/TOC and ASC/TOC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Compositional, Atomic and Molecular Analysis in Support of Materials Needs of the U.S. Air Force.

DTIC Science & Technology

1982-09-01

internally hydrogen-bonded monomer in .which the keto group is involved in the hydrogen bond but the acid carbonyl is not. 3 ) 3 - Bromopyruvic Acid...The spectra and structure of 3 - bromopyruvic acid were investigated and compared to those of pyruvic acid. It has been found that the spectra of 3 ...phase, cyclic monomer in dilute solution). The solid state spectra are quite different, however. The solid states spectra of 3 - bromopyruvic acid show a

Liquefaction of solid carbonaceous material with catalyst recycle

DOEpatents

Gupta, Avinash; Greene, Marvin I.

1992-01-01

In the two stage liquefaction of a carbonaceous solid such as coal wherein coal is liquefied in a first stage in the presence of a liquefaction solvent and the first stage effluent is hydrogenated in the presence of a supported hydrogenation catalyst in a second stage, catalyst which has been previously employed in the second stage and comminuted to a particle size distribution equivalent to 100% passing through U.S. 100 Mesh, is passed to the first stage to improve the overall operation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Swanee J.; Kozioziemski, Bernard J.

In this work, we performed a series of experiments to elucidate the characteristics of a good template for solid hydrogen nucleation. Zinc stands out among several materials with comparable size and shape. Nucleation could be observed to occur on top of sharp features, such as grain boundaries and cracks, but our attempts proved unsuccessful to fabricate or replicate such features. The variations of the supercooling (ΔT) values measured for comparable samples and the dependence of ΔT on the cell temperature cycling revealed that templated nucleation of solid hydrogen is a very delicate process.

Gas storage materials, including hydrogen storage materials

DOEpatents

Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

2013-02-19

A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

Gas storage materials, including hydrogen storage materials

DOEpatents

Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

2014-11-25

A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material, such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

Aryl C—H···Cl– Hydrogen Bonding in a Fluorescent Anion Sensor

PubMed Central

Tresca, Blakely W.; Zakharov, Lev N.; Carroll, Calden N.; Johnson, Darren W.; Haley, Michael M.

2014-01-01

A new phenyl-acetylene receptor containing a carbonaceous hydrogen bond donor activates anion binding in conjunction with two stabilizing ureas. The unusual CH···Cl– hydrogen bond is apparent in solution by large 1H NMR chemical shifts and by a short, linear contact in the solid state. PMID:23843050

Effect of layer thickness on the thermal release from Be-D co-deposited layers

NASA Astrophysics Data System (ADS)

Baldwin, M. J.; Doerner, R. P.

2014-08-01

The results of previous work (Baldwin et al 2013 J. Nucl. Mater. 438 S967-70 and Baldwin et al 2014 Nucl. Fusion 54 073005) are extended to explore the influence of layer thickness on the thermal D2 release from co-deposited Be-(0.05)D layers produced at ˜323 K. Bake desorption of layers of thickness 0.2-0.7 µm are explored with a view to examine the influence of layer thickness on the efficacy of the proposed ITER bake procedure, to be carried out at the fixed temperatures of 513 K on the first wall and 623 K in the divertor. The results of experiment and modelling with the TMAP-7 hydrogen transport code, show that thicker Be-D co-deposited layers are relatively more difficult to desorb (time-wise) than thinner layers with the same concentrations of intrinsic traps and retained hydrogen isotope fraction.

Temperature dependence of the spectrum of electrons levitating above solid hydrogen

NASA Astrophysics Data System (ADS)

Grigor'ev, P. D.; Dyugaev, A. M.; Lebedeva, E. V.

2008-03-01

A theory of photoresonance transitions for the electrons localized above the solid H2 surface is proposed on the basis of the experimental data obtained by V. V. Zav’yalov and I. I. Smol’yaninov [Pis’ma Zh. Éksp. Teor. Fiz. 44, 142 (1986); Zh. Éksp. Teor. Fiz. 92, 339 (1987); Zh. Éksp. Teor. Fiz. 94, 307 (1988)] and a simple model of condensed hydrogen, H2. A new explanation is offered for the strong dependence of the transition frequency v on the hydrogen vapor pressure revealed in the above-cited works. In contrast to the notions that were proposed by V. V. Zav’yalov and I. I. Smol’yaninov [Zh. Éksp. Teor. Fiz. 92, 339 (1987); Zh. Éksp. Teor. Fiz. 94, 307 (1988)]; and V. B. Shikin and S. N. Nazin [Pis’ma Zh. Éksp. Teor. Fiz. 82, 752 (2005)] and based on the effects of the quantum refraction of electrons by hydrogen vapor atoms, the temperature dependence of the frequency ν = ν ( T) is attributed here to the H2 vapor inhomogeneity. The nonanalytic dependence of ν on the vapor density n ν , ν( n ν ) - ν(0) ˜ n {/ν γ } ˜ e-Δ/ T , γ ≅ 0.56 has been revealed from the experimental data. The activation energy Δ corresponds to the “incomplete evaporation” of solid hydrogen [see J. I. Frenkel, Z. Phys. 26, 37 (1924); Kinetic Theory of Liquids (Nauka, Leningrad, 1945; Clarendon, Oxford, 1946)]. The parameter Δ is lower than the energy of the “complete evaporation” of solid H2 equal to 92.6 K.

In situ measurements of fuel retention by laser induced desorption spectroscopy in TEXTOR

NASA Astrophysics Data System (ADS)

Zlobinski, M.; Philipps, V.; Schweer, B.; Huber, A.; Stoschus, H.; Brezinsek, S.; Samm, U.; TEXTOR Team

2011-12-01

In future fusion devices such as ITER tritium retention due to tritium co-deposition in mixed material layers can be a serious safety problem. Laser induced desorption spectroscopy (LIDS) can measure the hydrogen content of hydrogenic carbon layers locally on plasma-facing components, while hydrogen is used as a tritium substitute. For several years, this method has been applied in the TEXTOR tokamak in situ during plasma operation to monitor the hydrogen content in space and time. This work shows the LIDS signal reproducibility and studies the effects of different plasma conditions, desorption distances from the plasma and different laser energies using a dedicated sample with constant hydrogen amount. Also the LIDS signal evaluation procedure is described in detail and the detection limits for different conditions in the TEXTOR tokamak are estimated.

The influence of reaction time on hydrogen sulphide removal from air by means of Fe(III)-EDTA/Fiban catalysts

NASA Astrophysics Data System (ADS)

Wasag, H.; Cel, W.; Chomczynska, M.; Kujawska, J.

2018-05-01

The paper deals with a new method of hydrogen sulphide removal from air by its filtration and selective catalytic oxidation with the use of fibrous carriers of Fe(III)-EDTA complex. The basis of these filtering materials includes fibrous ion exchangers with the complex immobilized on their functional groups. It has been established that the degree of catalytic hydrogen sulphide decomposition depends on the reaction time. Thus, the required degree of hydrogen sulphide removal from air could be easily controlled by applying appropriate thickness of the filtering layer under a given filtering velocity. It allows applying very thin filtering layers of the Fe(III)-EDTA/Fiban AK-22 or Fiban A-6 catalysts. The obtained results of the research confirm the applicability of these materials for deep air purification from hydrogen sulphide.

Hydrogen blistering under extreme radiation conditions

NASA Astrophysics Data System (ADS)

Sznajder, Maciej; Geppert, Ulrich; Dudek, Miroslaw

2018-01-01

Metallic surfaces, exposed to a proton flux, start to degradate by molecular hydrogen blisters. These are created by recombination of protons with metal electrons. Continued irradiation progresses blistering, which is undesired for many technical applications. In this work, the effect of the proton flux magnitude onto the degradation of native metal oxide layers and its consequences for blister formation has been examined. To study this phenomenon, we performed proton irradiation experiments of aluminium surfaces. The proton kinetic energy was chosen so that all recombined hydrogen is trapped within the metal structure. As a result, we discovered that intense proton irradiation increases the permeability of aluminium oxide layers for hydrogen atoms, thereby counteracting blister formation. These findings may improve the understanding of the hydrogen blistering process, are valid for all metals kept under terrestrial ambient conditions, and important for the design of proton irradiation tests.

40 CFR 60.591 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Bitumen) is a black or dark brown solid or semi-solid thermo-plastic material possessing waterproofing and... hydrogen ratio. It is essentially non-volatile at ambient temperatures with closed cup flash point of 445...

Effect of hydrogen on fatigue crack propagation in vanadium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, D.W.; Stoloff, N.S.

The influence of hydrogen on fatigue crack propagation in unalloyed vanadium and several hydrogen-charged vanadium alloys has been investigated. The Paris--Erdogan equation, da/dN = C(..delta..K)/sup m/, was approximately obeyed for all alloys. Crack growth rates were lowest in vanadium and dilute vanadium-hydrogen alloys, and were not very sensitive to volume fraction of hydrides in more concentrated alloys. The crack growth exponent, m, is inversely proportional to the cyclic strain hardening rate, n', and the rate constant C is inversely proportional to the square of the ultimate tensile stress, sigma/sub UTS/: metallographic examination showed hydride reorientation and growth in the originallymore » hydrided alloys. No stress-induced hydrides were observed in V-H solid-solution alloys. Fractures in hydrided materials exhibited cleavage-like features, while striations were noted in unalloyed vanadium and dilute solid-solution alloys.« less

Effect of hydrogen on fatigue crack propagation in vanadium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, D.W.; Stoloff, N.S.

The influence of hydrogen on fatigue crack propagation in unalloyed vanadium and several hydrogen-charged vanadium alloys has been investigated. The Paris--Erdogan equation, da/dN = C(..delta..K)/sup m/, was approximately obeyed for all alloys. Crack growth rates were lowest in vanadium and dilute vanadium--hydrogen alloys, and were not very sensitive to volume fraction of hydrides in more concentrated alloys. The crack growth exponent, m, is inversely proportional to the cyclic strain hardening rate, n', and the rate constant C is inversely proportional to the square of the ultimate tensile stress, sigma/sub UTS/: metallographic examination showed hydride reorientation and growth in the originallymore » hydrided alloys. No stress-induced hydrides were observed in V--H solid-solution alloys. Fractures in hydrided materials exhibited cleavage-like features, while striations were noted in unalloyed vanadium and dilute solid-solution alloys.« less

Terraced spreading of simple liquids on solid surfaces

NASA Technical Reports Server (NTRS)

Yang, Ju-Xing; Koplik, Joel; Banavar, Jayanth R.

1992-01-01

We have studied the spreading of liquid drops on a solid surface by molecular-dynamics simulations of coexisting three-phase Lennard-Jones systems of liquid, vapor, and solid. We consider both spherically symmetric atoms and diatomic molecules, and a range of interaction strengths. As the attraction between liquid and solid increases we observe a smooth transition in spreading regimes, from partial to complete to terraced wetting. In the terraced case, where distinct monomolecular layers spread with different velocities, the layers are ordered but not solid, with substantial molecular diffusion both within and between layers. The quantitative behavior resembles recent experimental findings, but the detailed dynamics differ. In particular, the layers exhibit an unusual spreading law, where their radii vary in time as R-squared approximately equal to log10t, which disagrees with experiments on polymeric liquids as well as recent calculations.

A review on on-board challenges of magnesium-based hydrogen storage materials for automobile applications

NASA Astrophysics Data System (ADS)

Rahman, Md. Wasikur

2017-06-01

The attempt of the review is to realize on-board hydrogen storage technologies concerning magnesium based solid-state matrix to allow fuel cell devices to facilitate sufficient storage capacity, cost, safety and performance requirements to be competitive with current vehicles. Hydrogen, a potential and clean fuel, can be applied in the state-of-the-art technology of `zero emission' vehicles. Hydrogen economy infrastructure both for stationary and mobile purposes is complicated due to its critical physico-chemical properties and materials play crucial roles in every stage of hydrogen production to utilization in fuel cells in achieving high conversion efficiency, safety and robustness of the technologies involved. Moreover, traditional hydrogen storage facilities are rather complicated due to its anomalous properties such as highly porous solids and polymers have intrinsic microporosity, which is the foremost favorable characteristics of fast kinetics and reversibility, but the major drawback is the low storage capacity. In contrast, metal hydrides and complex hydrides have high hydrogen storage capacity but thermodynamically unfavorable. Therefore, hydrogen storage is a real challenge to realize `hydrogen economy' that will solve the critical issues of humanity such as energy depletion, greenhouse emission, air pollution and ultimately climate change. Magnesium based materials, particularly magnesium hydride (MgH2) has been proposed as a potential hydrogen storage material due to its high gravimetric and volumetric capacity as well as environmentally benign properties to work the grand challenge out.

Proton conducting membranes for high temperature fuel cells with solid state water free membranes

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram R. (Inventor); Yen, Shiao-Pin S. (Inventor)

2006-01-01

A water free, proton conducting membrane for use in a fuel cell is fabricated as a highly conducting sheet of converted solid state organic amine salt, such as converted acid salt of triethylenediamine with two quaternized tertiary nitrogen atoms, combined with a nanoparticulate oxide and a stable binder combined with the converted solid state organic amine salt to form a polymeric electrolyte membrane. In one embodiment the membrane is derived from triethylenediamine sulfate, hydrogen phosphate or trifiate, an oxoanion with at least one ionizable hydrogen, organic tertiary amine bisulfate, polymeric quaternized amine bisulfate or phosphate, or polymeric organic compounds with quaternizable nitrogen combined with Nafion to form an intimate network with ionic interactions.

Hydrogen generation via photoelectrochemical water splitting using chemically exfoliated MoS{sub 2} layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, R. K., E-mail: r.joshi@unsw.edu.au, E-mail: alwarappan@cecri.res.in; Sahajwalla, V.; Shukla, S.

2016-01-15

Study on hydrogen generation has been of huge interest due to increasing demand for new energy sources. Photoelectrochemical reaction by catalysts was proposed as a promising technique for hydrogen generation. Herein, we report the hydrogen generation via photoelectrochecmial reaction using films of exfoliated 2-dimensional (2D) MoS{sub 2}, which acts as an efficient photocatalyst. The film of chemically exfoliated MoS{sub 2} layers was employed for water splitting, leading to hydrogen generation. The amount of hydrogen was qualitatively monitored by observing overpressure of a water container. The high photo-current generated by MoS{sub 2} film resulted in hydrogen evolution. Our work shows thatmore » 2D MoS{sub 2} is one of the promising candidates as a photocatalyst for light-induced hydrogen generation. High photoelectrocatalytic efficiency of the 2D MoS{sub 2} shows a new way toward hydrogen generation, which is one of the renewable energy sources. The efficient photoelectrocatalytic property of the 2D MoS{sub 2} is possibly due to availability of catalytically active edge sites together with minimal stacking that favors the electron transfer.« less

On the Mechanism of In Nanoparticle Formation by Exposing ITO Thin Films to Hydrogen Plasmas.

PubMed

Fan, Zheng; Maurice, Jean-Luc; Chen, Wanghua; Guilet, Stéphane; Cambril, Edmond; Lafosse, Xavier; Couraud, Laurent; Merghem, Kamel; Yu, Linwei; Bouchoule, Sophie; Roca I Cabarrocas, Pere

2017-10-31

We present our systematic work on the in situ generation of In nanoparticles (NPs) from the reduction of ITO thin films by hydrogen (H 2 ) plasma exposure. In contrast to NP deposition from the vapor phase (i.e., evaporation), the ITO surface can be considered to be a solid reservoir of In atoms thanks to H 2 plasma reduction. On one hand, below the In melting temperature, solid In NP formation is governed by the island-growth mode, which is a self-limiting process because the H 2 plasma/ITO interaction will be gradually eliminated by the growing In NPs that cover the ITO surface. On the other hand, we show that above the melting temperature In droplets prefer to grow along the grain boundaries on the ITO surface and dramatic coalescence occurs when the growing NPs connect with each other. This growth-connection-coalescence behavior is even strengthened on In/ITO bilayers, where In particles larger than 10 μm can be formed, which are made of evaporated In atoms and in situ released ones. Thanks to this understanding, we manage to disperse dense evaporated In NPs under H 2 plasma exposure when inserting an ITO layer between them and substrate like c-Si wafer or glass by modifying the substrate surface chemistry. Further studies are needed for more precise control of this self-assembling method. We expect that our findings are not limited to ITO thin films but could be applicable to various metal NPs generation from the corresponding metal oxide thin films.

Hydrogen bonded binary molecular adducts derived from exobidentate N-donor ligand with dicarboxylic acids: Acid⋯imidazole hydrogen-bonding interactions in neutral and ionic heterosynthons

NASA Astrophysics Data System (ADS)

Kathalikkattil, Amal Cherian; Damodaran, Subin; Bisht, Kamal Kumar; Suresh, Eringathodi

2011-01-01

Four new binary molecular compounds between a flexible exobidentate N-heterocycle and a series of dicarboxylic acids have been synthesized. The N-donor 1,4-bis(imidazol-1-ylmethyl)benzene (bix) was reacted with flexible and rigid dicarboxylic acids viz., cyclohexane-1,4-dicarboxylic acid (H 2chdc), naphthalene-1,4-dicarboxylic acid (H 2npdc) and 1H-pyrazole-3,5-dicarboxylic acid (H 2pzdc), generating four binary molecular complexes. X-ray crystallographic investigation of the molecular adducts revealed the primary intermolecular interactions carboxylic acid⋯amine (via O-H⋯N) as well as carboxylate⋯protonated amine (via N-H +⋯O -) within the binary compounds, generating layered and two-dimensional sheet type H-bonded networks involving secondary weak interactions (C-H⋯O) including the solvent of crystallization. Depending on the differences in p Ka values of the selected base/acid (Δp Ka), diverse H-bonded supramolecular assemblies could be premeditated. This study demonstrates the H-bonding interactions between imidazole/imidazolium cation and carboxylic acid/carboxylate anion in providing sufficient driving force for the directed assembly of binary molecular complexes. In the two-component solid form of hetero synthons involving bix and dicarboxylic acid, only H 2chdc exist as cocrystal with bix, while all the other three compounds crystallized exclusively as salt, in agreement with the Δp Ka values predicted for the formation of salts/cocrystals from the base and acid used in the synthesis of supramolecular solids.

Synergizing Noncovalent Bonding Interactions in the Self-Assembly of Organic Charge-Transfer Ferroelectrics and Metal-Organic Frameworks

NASA Astrophysics Data System (ADS)

Cao, Dennis

Contemporary supramolecular chemistry---chemistry beyond the molecule---seeks to leverage noncovalent bonding interactions to generate emergent properties and complexity. These aims extend beyond the solution phase and into the solid state, where crystalline organic materials have attracted much attention for their ability to imitate the physical properties of inorganic crystals. This Thesis outlines my efforts to understand the properties of the solid-state materials that are self-assembled with noncovalent bonding motifs which I have helped to realize. In the first five Chapters, I chronicle the development of the lock-arm supramolecular ordering (LASO) paradigm, which is a general molecular design strategy for amplifying the crystallization of charge transfer complexes that revolves around the synergistic action of hydrogen bonding and charge transfer interactions. In an effort to expand upon the LASO paradigm, I identify a two-point halogen-bonding motif which appears to operate orthogonally from the hydrogen bonding and charge transfer interactions. Since some of these single crystalline materials are ferroelectric at room temperature, I discuss the implications of these experimental observations and reconcile them with the centrosymmetric space groups assigned after X-ray crystallographic refinements. I conclude in the final two Chapters by recording my endeavors to control the assembly of metal-organic frameworks (MOFs) with noncovalent bonding interactions between [2]catenane-bearing struts. First of all, I describe the formation of syndiotactic pi-stacked 2D MOF layers before highlighting a two-component MOF that assembles with a magic number ratio of components that is independent of the molar proportions present in the crystallization medium.

Numerical modeling of heat transfer during hydrogen absorption in thin double-layered annular ZrCo beds

NASA Astrophysics Data System (ADS)

Cui, Yehui; Zeng, Xiangguo; Kou, Huaqin; Ding, Jun; Wang, Fang

2018-06-01

In this work a three-dimensional (3D) hydrogen absorption model was proposed to study the heat transfer behavior in thin double-layered annular ZrCo beds. Numerical simulations were performed to investigate the effects of conversion layer thickness, thermal conductivity, cooling medium and its flow velocity on the efficiency of heat transfer. Results reveal that decreasing the layer thickness and improving the thermal conductivity enhance the ability of heat transfer. Compared with nitrogen and helium, water appears to be a better medium for cooling. In order to achieve the best efficiency of heat transfer, the flow velocity needs to be maximized.

Laser treatment of plasma-hydrogenated silicon wafers for thin layer exfoliation

NASA Astrophysics Data System (ADS)

Ghica, Corneliu; Nistor, Leona Cristina; Teodorescu, Valentin Serban; Maraloiu, Adrian; Vizireanu, Sorin; Scarisoreanu, Nae Doinel; Dinescu, Maria

2011-03-01

We have studied by transmission electron microscopy the microstructural effects induced by pulsed laser annealing in comparison with thermal treatments of RF plasma hydrogenated Si wafers aiming for further application in the smart-cut procedure. While thermal annealing mainly produces a slight decrease of the density of plasma-induced planar defects and an increase of the size and number of plasma-induced nanocavities in the Si matrix, pulsed laser annealing of RF plasma hydrogenated Si wafers with a 355 nm wavelength radiation results in both the healing of defects adjacent to the wafer surface and the formation of a well defined layer of nanometric cavities at a depth of 25-50 nm. In this way, a controlled fracture of single crystal layers of Si thinner than 50 nm is favored.

Effect of Mass Proportion of Municipal Solid Waste Incinerator Bottom Ash Layer to Municipal Solid Waste Layer on the Cu and Zn Discharge from Landfill

PubMed Central

Kong, Qingna; Qiu, Zhanhong; Shen, Dongsheng

2016-01-01

Municipal solid waste incinerator (MSWI) bottom ash is often used as the protection layer for the geomembrane and intermediate layer in the landfill. In this study, three sets of simulated landfills with different mass proportion of MSWI bottom ash layer to municipal solid waste (MSW) layer were operated. Cu and Zn concentrations in the leachates and MSW were monitored to investigate the effect of MSWI bottom ash layer on the Cu and Zn discharge from the landfill. The results showed that the Zn discharge was dependent on the mass proportion of MSWI bottom ash layer. The pH of landfill was not notably increased when the mass proportion of MSWI bottom ash layer to MSW layer was 1 : 9, resulting in the enhancement of the Zn discharge. However, Zn discharge was mitigated when the mass proportion was 2 : 8, as the pH of landfill was notably promoted. The discharge of Cu was not dependent on the mass proportion, due to the great affinity of Cu to organic matter. Moreover, Cu and Zn contents of the sub-MSW layer increased due to the MSWI bottom ash layer. Therefore, the MSWI bottom ash layer can increase the potential environmental threat of the landfill. PMID:28044139

Environment-dependent conformation investigation of 3-amino-1,2,4-triazole (3-AT): Raman Spectroscopy and density functional theory

NASA Astrophysics Data System (ADS)

Meng, Shuang; Zhao, Yanying; Xue, Jiadan; Zheng, Xuming

2018-02-01

In the paper, diverse tautomers of 3-amino-1,2,4-triazole (3AT) in solid and polar solvent have been explored by FT-IR, FT-Raman and 488 nm Raman experiments combing with quantum chemical theoretical calculation using PCM solvent model and normal mode analysis. The vibrational spectra prefer the 3-amino-1,2,4-2H-triazole (2H-3AT) dimer in solid, while in a polar solvent 3AT is apt to the 3-amino-1,2,4-2H-triazole (2H-3AT) monomer. The significant wavenumber difference and Raman intensity patterns in solid and different solvents are induced by hydrogen bond perturbation along > NH ⋯ N ≤ hydrogen bonds on five-membered N-heterocyclic ring. The ground state proton transfer reaction mechanism along the five-membered N-heterocyclic ring is supported by intermolecular hydrogen bonding between 3AT and protonic solvent molecules.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramkumar, Shwetha; Fan, Liang-Shih

A process for producing hydrogen comprising the steps of: (i) gasifying a fuel into a raw synthesis gas comprising CO, hydrogen, steam, sulfur and halide contaminants in the form of H.sub.2S, COS, and HX, wherein X is a halide; (ii) passing the raw synthesis gas through a water gas shift reactor (WGSR) into which CaO and steam are injected, the CaO reacting with the shifted gas to remove CO.sub.2, sulfur and halides in a solid-phase calcium-containing product comprising CaCO.sub.3, CaS and CaX.sub.2; (iii) separating the solid-phase calcium-containing product from an enriched gaseous hydrogen product; and (iv) regenerating the CaO bymore » calcining the solid-phase calcium-containing product at a condition selected from the group consisting of: in the presence of steam, in the presence of CO.sub.2, in the presence of synthesis gas, in the presence of H.sub.2 and O.sub.2, under partial vacuum, and combinations thereof.« less

Process for hydrocracking carbonaceous material in liquid carrier

DOEpatents

Duncan, Dennis A.

1980-01-01

Solid carbonaceous material is hydrocracked to provide aliphatic and aromatic hydrocarbons for use as gaseous and liquid fuels or chemical feed stock. Particulate carbonaceous material such as coal in slurry with recycled product oil is preheated in liquid state to a temperature of 600.degree.-1200.degree. F. in the presence of hydrogen gas. The product oil acts as a sorbing agent for the agglomerating bitumins to minimize caking within the process. In the hydrocracking reactor, the slurry of oil and carbonaceous particles is heated within a tubular passageway to vaporize the oil and form a gas-solid mixture which is further heated to a hydropyrolysis temperature in excess of 1200.degree. F. The gas-solid mixture is quenched by contact with additional oil to condense normally liquid hydrocarbons for separation from the gases. A fraction of the hydrocarbon liquid product is recycled for quenching and slurrying with the carbonaceous feed. Hydrogen is recovered from the gas for recycle and additional hydrogen is produced by gasification of residual char.

The electrochemistry of "solid/water" interfaces involved in PEM-H2O reactors: part I. The "Pt/water" interfaces.

PubMed

Wang, Qiang; Cha, Chuan-Sin; Lu, Juntao; Zhuang, Lin

2009-01-28

The nature and properties of Pt surfaces in contact with pure water in PEM-H2O reactors were mimetically studied by employing CV measurements with microelectrode techniques. These "Pt/water" interfaces were found to be electrochemically polarizable, and the local interfacial potential relative to reversible hydrogen electrode (RHE) potential in pure water is numerically the same as the potential value measured against a RHE in contact with PEM as the reference electrode. However, the structural parameters of the electric double layer at the "Pt/water" interfaces can be quite different from those at the "Pt/PEM" interfaces, and the kinetics of electrode processes could be seriously affected by the structure of electric double layer in pure water media. Besides, there is active diffusional flow of intermediates of electrode reactions between the "Pt/water" and the "Pt/PEM" interfaces, thus facilitating the active involvement of the "Pt/water" interfaces in the current-generation mechanism of PEM fuel cells and other types of PEM-H2O reactors.

Putting Cocrystal Stoichiometry to Work: A Reactive Hydrogen-Bonded "Superassembly" Enables Nanoscale Enlargement of a Metal-Organic Rhomboid via a Solid-State Photocycloaddition.

PubMed

Chu, Qianli; Duncan, Andrew J E; Papaefstathiou, Giannis S; Hamilton, Tamara D; Atkinson, Manza B J; Mariappan, S V Santhana; MacGillivray, Leonard R

2018-04-11

Enlargement of a self-assembled metal-organic rhomboid is achieved via the organic solid state. The solid-state synthesis of an elongated organic ligand was achieved by a template directed [2 + 2] photodimerization in a cocrystal. Initial cocrystals obtained of resorcinol template and reactant alkene afforded a 1:2 cocrystal with the alkene in a stacked yet photostable geometry. Cocrystallization performed in the presence of excess template resulted in a 3:2 cocrystal composed of novel discrete 10-component hydrogen-bonded "superassemblies" wherein the alkenes undergo a head-to-head [2 + 2] photodimerization. Isolation and reaction of elongated photoproduct with Cu(II) ions afforded a metal-organic rhomboid of nanoscale dimensions that hosts small molecules in the solid state as guests.

Solid state transport-based thermoelectric converter

DOEpatents

Hu, Zhiyu

2010-04-13

A solid state thermoelectric converter includes a thermally insulating separator layer, a semiconducting collector and an electron emitter. The electron emitter comprises a metal nanoparticle layer or plurality of metal nanocatalyst particles disposed on one side of said separator layer. A first electrically conductive lead is electrically coupled to the electron emitter. The collector layer is disposed on the other side of the separator layer, wherein the thickness of the separator layer is less than 1 .mu.m. A second conductive lead is electrically coupled to the collector layer.

High Pressure and High Temperature State of Oxygen Enriched Ice

NASA Astrophysics Data System (ADS)

LI, M.; Zhang, S.; Jeanloz, R.; Militzer, B.

2016-12-01

Interior models for Uranus and Neptune include a hydrogen/helium/water outer envelope and a core of rock and metal at the center, with superionic water-rich ice proposed as comprising an intermediate layer. Here we consider an oxygen-enriched ice, such as H2O2 hydrogen peroxide (± water), that could form through chemical reaction between water-rich and underlying rocky (i.e., oxygen-rich) layers. As oxygen and its compounds (e.g., H2O, SiO2) form metallic fluids at pressures above 100-150 GPa, the problem amounts to considering oxygen alloying of semiconducting or metallic water. The density of H2O2 is 1.45 g/cc at ambient pressure and 0° C, increasing to 1.71 g/cc in the solid state at about -20° C. There are no Hugoniot data beyond 30 GPa, so we estimated Hugoniots for H2O2 with different initial densities, using both a mixing model based on Hugoniot data for H2O2 and 1/2 O2 (molar volume summation under pressure) and ab initio calculations for unreacted H2O2. The results agree with each other to pressures of about 200 GPa, and the ab initio calculations show evidence of a superionic state at temperatures as low as 500 K, much lower than for water ice. Hydrogen peroxide is expected to be liquid along planetary isentropes for Uranus and Neptune, suggesting that H2O2 may not be present as a pure compound in these planets. Instead, oxygen-enriched H2O ice may be the relevant form of water and oxygen, and might be produced in the laboratory by way of dynamic compression of H2O2 or laser-heating of statically compressed H2O + O2 and/or H2O2.

Fabrication and characterization of solid oxide cells for energy conversion and storage

NASA Astrophysics Data System (ADS)

Yang, Chenghao

2011-12-01

There has been an increasing interest in clean and renewable energy generation for highlighted energy and environmental concerns. Solid oxide cells (SOCs) have been considered as one of the promising technologies, since they can be operated efficiently both in electrolysis mode by generating hydrogen through steam electrolysis and fuel cell mode by electrochemically combining fuel with oxidant. The present work is devoted to performing a fundamental study of SOC in both fuel cell mode for power generation and electrolysis mode for fuel production. The research work on SOCs that can be operated reversibly for power generation and fuel production has been conducted in the following six projects: (1) High performance solid oxide electrolysis cell (SOEC) Fabrication of novel structured SOEC oxygen electrode with the conventional and commercial solid oxide fuel cell materials by screen-printing and infiltration fabrication methods. The microstructure, electrochemical properties and durability of SOECs has been investigated. It was found that the LSM infiltrated cell has an area specific resistance (ASR) of 0.20 Ω cm2 at 900°C at open circuit voltage with 50% absolute humidity (AH), which is relatively lower than that of the cell with LSM-YSZ oxygen electrode made by a conventional mixing method. Electrolysis cell with LSM infiltrated oxygen electrode has demonstrated stable performance under electrolysis operation with 0.33 A/cm2 and 50 vol.% AH at 800°C. (2) Advanced performance high temperature micro-tubular solid oxide fuel cell (MT-SOFC) Phase-inversion, dip-coating, high temperature co-sintering process and impregnation method were used to fabricate micro-tubular solid oxide fuel cell. The micro-structure of the micro-tubular fuel cell will be investigated and the power output and thermal robustness has been evaluated. High performance and rapid start-up behavior have been achieved, indicates that the MT-SOFC developed in this work can be a promising technology for portable applications. (3) Promising intermediate temperature micro-tubular solid oxide fuel cells for portable power supply applications Maximum power densities of 0.5, 0.38 and 0.27 W/cm2 have been obtained using H2-15% H2O as fuel at 550, 600 and 650°C, respectively. Quick thermal cycles performed on the intermediate temperature MT-SOFC stability demonstrate that the cell has robust performance stability for portable applications. (4) Micro-tubular solid oxide cell (MT-SOC) for steam electrolysis The electrochemical properties of MT-SOC will be investigated in detail in electrolysis mode. The mechanism of the novel hydrogen electrode structure benefiting the cell performance will be demonstrated systematically. The high electrochemical performance of the MT-SOC in electrolysis mode indicates that MT-SOC can provide an efficient hydrogen generation process. (5) Micro-tubular solid oxide cell (MT-SOC) for steam and CO2 co-electrolysis The MT-SOC will be operated in co-electrolysis mode for steam and CO 2, which will provide an efficient approach to generate syngas (H2+CO) without consuming fossil fuels. This can potentially provide an alternative superior approach for carbon sequestration which has been a critical issue facing the sustainability of our society. (6) Steam and CO2 co-electrolysis using solid oxide cells fabricated by freeze-drying tape-casting Tri-layer scaffolds have been prepared by freeze-drying tape casting process and the electrode catalysts are obtained by infiltrating the porous electrode substrates. Button cells will be tested for co-electrolysis of steam and CO2. The mechanism and efficiency of steam and CO2 co-electrolysis will be systemically investigated. In conclusion, SOCs have been fabricated with conventional materials and evaluated, but their performance has been found to be limited in either SOFC or SOEC mode. The cell performance has been significantly improved by employing an infiltrated LSM-YSZ electrode, due to dramatically decreased polarization resistance. However, mass transport limitation has been observed, particularly in electrolysis mode. By utilizing micro-tubular SOCs with novel hydrogen electrode produced via a phase inversion method, mass transport limitation has been mitigated. Finally, mass transport has been further improved by using cells with electrodes fabricated through a freeze-drying tape-casting method. (Abstract shortened by UMI.)

Influence of surface oxides on hydrogen-sensitive Pd:GaN Schottky diodes

NASA Astrophysics Data System (ADS)

Weidemann, O.; Hermann, M.; Steinhoff, G.; Wingbrant, H.; Lloyd Spetz, A.; Stutzmann, M.; Eickhoff, M.

2003-07-01

The hydrogen response of Pd:GaN Schottky diodes, prepared by in situ and ex situ deposition of catalytic Pd Schottky contacts on Si-doped GaN layers is compared. Ex situ fabricated devices show a sensitivity towards molecular hydrogen, which is about 50 times higher than for in situ deposited diodes. From the analysis of these results, we conclude that adsorption sites for atomic hydrogen in Pd:GaN sensors are provided by an oxidic intermediate layer. In addition, in situ deposited Pd Schottky contacts reveal lower barrier heights and drastically higher reverse currents. We suggest that the passivation of the GaN surface before ex situ deposition of Pd also results in quenching of leakage paths caused by structural defects.

8-Hy­droxy­quinolin-1-ium hydrogen sulfate monohydrate

PubMed Central

Damous, Maamar; Dénès, George; Bouacida, Sofiane; Hamlaoui, Meriem; Merazig, Hocine; Daran, Jean-Claude

2013-01-01

In the crystal structure of the title salt hydrate, C9H8NO+·HSO4 −·H2O, the quinoline N—H atoms are hydrogen bonded to the bis­ulfate anions. The bis­ulfate anions and water mol­ecules are linked together by O—H⋯O hydrogen-bonding inter­actions. The cations and anions form separate layers alternating along the c axis, which are linked by N—H⋯O and O—H⋯O hydrogen bonds into a two-dimensional network parallel to (100). Further O—H⋯O contacts connect these layers, forming a three-dimensional network, in which two R 4 4(12) rings and C 2 2(13) infinite chains can be identified. PMID:24427083

Three-dimensional supramolecular architecture in imidazolium hydrogen 2,3,5,6-tetrafluoroterephthalate.

PubMed

Yu, Li-Li; Cheng, Mei-Ling; Liu, Qi; Zhang, Zhi-Hui; Chen, Qun

2010-04-01

The asymmetric unit of the title salt formed between 2,3,5,6-tetrafluoroterephthalic acid (H(2)tfbdc) and imidazolium (ImH), C(3)H(5)N(2)(+).C(8)HF(4)O(4)(-), contains one Htfbdc(-) anion and one ImH(2)(+) cation, joined by a classical N-H...O hydrogen bond. The acid and base subunits are further linked by N-H...O and O-H...O hydrogen bonds into infinite two-dimensional layers with R(6)(5)(32) hydrogen-bond motifs. The resulting (4,4) network layers interpenetrate to produce an interlocked three-dimensional structure. The final three-dimensional supramolecular architecture is further stabilized by the linkages of two C-H...O interactions.

Solid-state acid-base interactions in complexes of heterocyclic bases with dicarboxylic acids: crystallography, hydrogen bond analysis, and 15N NMR spectroscopy.

PubMed

Li, Z Jane; Abramov, Yuriy; Bordner, Jon; Leonard, Jason; Medek, Ales; Trask, Andrew V

2006-06-28

A cancer candidate, compound 1, is a weak base with two heterocyclic basic nitrogens and five hydrogen-bonding functional groups, and is sparingly soluble in water rendering it unsuitable for pharmaceutical development. The crystalline acid-base pairs of 1, collectively termed solid acid-base complexes, provide significant increases in the solubility and bioavailability compared to the free base, 1. Three dicarboxylic acid-base complexes, sesquisuccinate 2, dimalonate 3, and dimaleate 4, show the most favorable physicochemical profiles and are studied in greater detail. The structural analyses of the three complexes using crystal structure and solid-state NMR reveal that the proton-transfer behavior in these organic acid-base complexes vary successively correlating with Delta pKa. As a result, 2 is a neutral complex, 3 is a mixed ionic and zwitterionic complex and 4 is an ionic salt. The addition of the acidic components leads to maximized hydrogen bond interactions forming extended three-dimensional networks. Although structurally similar, the packing arrangements of the three complexes are considerably different due to the presence of multiple functional groups and the flexible backbone of 1. The findings in this study provide insight into the structural characteristics of complexes involving heterocyclic bases and carboxylic acids, and demonstrate that X-ray crystallography and 15N solid-state NMR are truly complementary in elucidating hydrogen bonding interactions and the degree of proton transfer of these complexes.

Crystal structures of 2-[(4,6-di-amino-pyrimidin-2-yl)sulfan-yl]-N-(naphthalen-1-yl)acetamide and 2-[(4,6-di-amino-pyrimidin-2-yl)sulfan-yl]-N-(4-fluoro-phen-yl)acetamide.

PubMed

Subasri, S; Kumar, Timiri Ajay; Sinha, Barij Nayan; Jayaprakash, Venkatesan; Viswanathan, Vijayan; Velmurugan, Devadasan

2017-02-01

The title compounds, C 16 H 15 N 5 OS, (I), and C 12 H 12 FN 5 OS, (II), are [(di-amino-pyrimidine)-sulfan-yl]acetamide derivatives. In (I), the pyrimidine ring is inclined to the naphthalene ring system by 55.5 (1)°, while in (II), the pyrimidine ring is inclined to the benzene ring by 58.93 (8)°. In (II), there is an intra-molecular N-H⋯N hydrogen bond and a short C-H⋯O contact. In the crystals of (I) and (II), mol-ecules are linked by pairs of N-H⋯N hydrogen bonds, forming inversion dimers with R 2 2 (8) ring motifs. In the crystal of (I), the dimers are linked by bifurcated N-H⋯(O,O) and C-H⋯O hydrogen bonds, forming layers parallel to (100). In the crystal of (II), the dimers are linked by N-H⋯O hydrogen bonds, also forming layers parallel to (100). The layers are linked by C-H⋯F hydrogen bonds, forming a three-dimensional architecture.

Kinetics and Catalysis Demonstrations.

ERIC Educational Resources Information Center

Falconer, John L.; Britten, Jerald A.

1984-01-01

Eleven videotaped kinetics and catalysis demonstrations are described. Demonstrations include the clock reaction, oscillating reaction, hydrogen oxidation in air, hydrogen-oxygen explosion, acid-base properties of solids, high- and low-temperature zeolite reactivity, copper catalysis of ammonia oxidation and sodium peroxide decomposition, ammonia…

Continuous catalytic decomposition of methane

NASA Technical Reports Server (NTRS)

Clifford, J. E.; Hillenbrand, L. J.; Kim, B. C.; Kolic, E. S.; Zupan, J.

1973-01-01

Water is conserved by employing sequence of reactions whereby 75 percent of methane from Sabatier reaction is decomposed to solid carbon and hydrogen; hydrogen is then separated from residual methane and utilized in usual Sabatier reaction to reduce remaining metabolic carbon dioxide.

High permeance sulfur tolerant Pd/Cu alloy membranes

DOEpatents

Ma, Yi Hua; Pomerantz, Natalie

2014-02-18

A method of making a membrane permeable to hydrogen gas (H.sub.2.uparw.) is disclosed. The membrane is made by forming a palladium layer, depositing a layer of copper on the palladium layer, and galvanically displacing a portion of the copper with palladium. The membrane has improved resistance to poisoning by H.sub.2S compared to a palladium membrane. The membrane also has increased permeance of hydrogen gas compared to palladium-copper alloys. The membrane can be annealed at a lower temperature for a shorter amount of time.

Final Technical Report, Oct 2004 - Nov. 2006, High Performance Flexible Reversible Solid Oxide Fuel Cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guan, Jie; Minh, Nguyen

This report summarizes the work performed for the program entitled “High Performance Flexible Reversible Solid Oxide Fuel Cell” under Cooperative Agreement DE-FC36-04GO14351 for the U. S. Department of Energy. The overall objective of this project is to demonstrate a single modular stack that generates electricity from a variety of fuels (hydrogen and other fuels such as biomass, distributed natural gas, etc.) and when operated in the reverse mode, produces hydrogen from steam. This project has evaluated and selected baseline cell materials, developed a set of materials for oxygen and hydrogen electrodes, and optimized electrode microstructures for reversible solid oxide fuelmore » cells (RSOFCs); and demonstrated the feasibility and operation of a RSOFC multi-cell stack. A 10-cell reversible SOFC stack was operated over 1000 hours alternating between fuel cell (with hydrogen and methane as fuel) and steam electrolysis modes. The stack ran very successfully with high power density of 480 mW/cm2 at 0.7V and 80% fuel utilization in fuel cell mode and >6 SLPM hydrogen production in steam electrolysis mode using about 1.1 kW electrical power. The hydrogen generation is equivalent to a specific capability of 2.59 Nm3/m2 with electrical energy demand of 3 kWh/Nm3. The performance stability in electrolysis mode was improved vastly during the program with a degradation rate reduction from 8000 to 200 mohm-cm2/1000 hrs. This was accomplished by increasing the activity and improving microstructure of the oxygen electrode. Both cost estimate and technology assessment were conducted. Besides the flexibility running under both fuel cell mode and electrolysis mode, the reversible SOFC system has the potentials for low cost and high efficient hydrogen production through steam electrolysis. The cost for hydrogen production at large scale was estimated at ~$2.7/kg H2, comparing favorably with other electrolysis techology.« less

In-plane InSb nanowires grown by selective area molecular beam epitaxy on semi-insulating substrate.

PubMed

Desplanque, L; Bucamp, A; Troadec, D; Patriarche, G; Wallart, X

2018-07-27

In-plane InSb nanostructures are grown on a semi-insulating GaAs substrate using an AlGaSb buffer layer covered with a patterned SiO 2 mask and selective area molecular beam epitaxy. The shape of these nanostructures is defined by the aperture in the silicon dioxide layer used as a selective mask thanks to the use of an atomic hydrogen flux during the growth. Transmission electron microscopy reveals that the mismatch accommodation between InSb and GaAs is obtained in two steps via the formation of an array of misfit dislocations both at the AlGaSb buffer layer/GaAs and at the InSb nanostructures/AlGaSb interfaces. Several micron long in-plane nanowires (NWs) can be achieved as well as more complex nanostructures such as branched NWs. The electrical properties of the material are investigated by the characterization of an InSb NW MOSFET down to 77 K. The resulting room temperature field effect mobility values are comparable with those reported on back-gated MOSFETs based on InSb NWs obtained by vapor liquid solid growth or electrodeposition. This growth method paves the way to the fabrication of complex InSb-based nanostructures.

Modification of the Near Surface Region Metastable Phases and Ion Induced Reactions

DTIC Science & Technology

1984-02-03

cell Si Dave Lilienfeld - amorphous Si layer thickness Au diffusion in metallic glasses Dave Lilienfeld & - low temperature Cu diffusion in Si Tim...Sullivan Fritz Stafford - defect characterization in implanted & annealed silicon-on-sapphire Peter Zielinski - Composition of CuZr metallic glass...ribbons 5. Prof. Johnson Dave Kuhn - measurement of Pd layer thickness Alexandra Elve - hydrogen profiles in metals Lauren Heitner - hydrogen diffusion in

Camera flash heating of a three-layer solid composite: An approximate solution

NASA Astrophysics Data System (ADS)

Jibrin, Sani; Moksin, Mohd Maarof; Husin, Mohd Shahril; Zakaria, Azmi; Hassan, Jumiah; Talib, Zainal Abidin

2014-03-01

Camera flash heating and the subsequent thermal wave propagation in a solid composite material is studied using the Laplace transform technique. Full-field rear surface temperature for a single-layer, two-layer and three-layer solid composites are obtained directly from the Laplace transform conversion tables as opposed to the tedious inversion process by integral transform method. This is achieved by first expressing the hyperbolic-transcendental equation in terms of negative exponentials of square root of s/α and expanded same in a series by the binomial theorem. Electrophoretic deposition (EPD) and dip coating processes were used to prepare three-layer solid composites consisting ZnO/Cu/ZnO and starch/Al/starch respectively. About 0.5ml of deionized water enclosed within an air-tight aluminium container serves as the third three layer sample (AL/water/AL). Thermal diffusivity experiments were carried out on all the three samples prepared. Using Scaled Levenberg-Marquardt algorithm, the approximate temperature curve for the three-layer solid composite is fitted with the corresponding experimental result. The agreement between the theoretical curve and the experimental data as well as that between the obtained thermal diffusivity values for the ZnO, aluminium and deionized water in this work and similar ones found in literature is found to be very good.

Hydrogen-bromine fuel cell advance component development

NASA Technical Reports Server (NTRS)

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.

Hydrogen leak detection using laser-induced breakdown spectroscopy.

PubMed

Ball, A J; Hohreiter, V; Hahn, D W

2005-03-01

Laser-induced breakdown spectroscopy (LIBS) is investigated as a technique for real-time monitoring of hydrogen gas. Two methodologies were examined: The use of a 100 mJ laser pulse to create a laser-induced breakdown directly in a sample gas stream, and the use of a 55 mJ laser pulse to create a laser-induced plasma on a solid substrate surface, with the expanding plasma sampling the gas stream. Various metals were analyzed as candidate substrate surfaces, including aluminum, copper, molybdenum, stainless steel, titanium, and tungsten. Stainless steel was selected, and a detailed analysis of hydrogen detection in binary mixtures of nitrogen and hydrogen at atmospheric pressure was performed. Both the gaseous plasma and the plasma initiated on the stainless steel surface generated comparable hydrogen emission signals, using the 656.28 Halpha emission line, and exhibited excellent signal linearity. The limit of detection is about 20 ppm (mass) as determined for both methodologies, with the solid-initiated plasma yielding a slightly better value. Overall, LIBS is concluded to be a viable candidate for hydrogen sensing, offering a combination of high sensitivity with a technique that is well suited to implementation in field environments.

Structure of H2Ti3O7 and its evolution during sodium insertion as anode for Na ion batteries.

PubMed

Eguía-Barrio, Aitor; Castillo-Martínez, Elizabeth; Zarrabeitia, Maider; Muñoz-Márquez, Miguel A; Casas-Cabanas, Montse; Rojo, Teófilo

2015-03-14

H2Ti3O7 was prepared as a single phase material by ionic exchange from Na2Ti3O7. The complete ionic exchange was confirmed by (1)H and (23)Na solid state Nuclear Magnetic Resonance (NMR). The atomic positions of H2Ti3O7 were obtained from the Rietveld refinement of powder X-ray diffraction (PXRD) and neutron diffraction experimental data, the latter collected at two different wavelengths to precisely determine the hydrogen atomic positions in the structure. All H(+) cations are hydrogen bonded to two adjacent [Ti3O7](2-) layers leading to the gliding of the layers and lattice centring with respect to the parent Na2Ti3O7. In contrast with a previous report where protons were located in two different positions of H2Ti3O7, 3 types of proton positions were found. Two of the three types of proton are bonded to the only oxygen linked to a single titanium atom forming an H-O-H angle close to that of the water molecule. H2Ti3O7 is able to electrochemically insert Na(+). The electrochemical insertion of sodium into H2Ti3O7 starts with a solid solution regime of the C-centred phase. Then, between 0.6 and 1.2 inserted Na(+) the reaction proceeds through a two phase reaction and a plateau at 1.3 V vs. Na(+)/Na is observed in the voltage-composition curve. The second phase resembles the primitive Na2Ti3O7 cell as detected by in situ PXRD. Upon oxidation, from 0.9 to 2.2 V, the PXRD pattern remains mostly unchanged probably due to H(+) removal instead of Na(+), with the capacity quickly fading upon cycling. Conditioning H2Ti3O7 for two cycles at 0.9-2.2 V before cycling in the 0.05-1.6 V range yields similar specific capacity and better retention than the original Na2Ti3O7 in the same voltage range.

The supramolecular architecture of tris(naphthalene-1,5-diaminium) bis(5-aminonaphthalen-1-aminium) octakis[hydrogen (5-carboxypyridin-3-yl)phosphonate].

PubMed

Wilk, Magdalena; Janczak, Jan; Videnova-Adrabinska, Veneta

2012-09-01

The asymmetric unit of the title compound, 3C(10)H(12)N(2)(2+)·2C(10)H(11)N(2)(+)·8C(6)H(5)NO(5)P(-), contains one and a half naphthalene-1,5-diaminium cations, in which the half-molecule has inversion symmetry, one 5-aminonaphthalen-1-aminium cation and four hydrogen (5-carboxypyridin-3-yl)phosphonate anions. The crystal structure is layered and consists of hydrogen-bonded anionic monolayers between which the cations are arranged. The acid monoanions are organized into one-dimensional chains along the [101] direction via hydrogen bonds established between the phosphonate sites. (C)O-H···N(py) hydrogen bonds (py is pyridine) crosslink the chains to form an undulating (010) monolayer. The cations serve both to balance the charge of the anionic network and to connect neighbouring layers via multiple hydrogen bonds to form a three-dimensional supramolecular architecture.

Apparatus and method for transient thermal infrared emission spectrometry

DOEpatents

McClelland, John F.; Jones, Roger W.

1991-12-24

A method and apparatus for enabling analysis of a solid material (16, 42) by applying energy from an energy source (20, 70) top a surface region of the solid material sufficient to cause transient heating in a thin surface layer portion of the solid material (16, 42) so as to enable transient thermal emission of infrared radiation from the thin surface layer portion, and by detecting with a spectrometer/detector (28, 58) substantially only the transient thermal emission of infrared radiation from the thin surface layer portion of the solid material. The detected transient thermal emission of infrared radiation is sufficiently free of self-absorption by the solid material of emitted infrared radiation, so as to be indicative of characteristics relating to molecular composition of the solid material.

Multilayer heterostructures and their manufacture

DOEpatents

Hammond, Scott R; Reese, Matthew; Rupert, Benjamin; Miedaner, Alexander; Curtis, Clavin; Olson, Dana; Ginley, David S

2015-11-04

A method of synthesizing multilayer heterostructures including an inorganic oxide layer residing on a solid substrate is described. Exemplary embodiments include producing an inorganic oxide layer on a solid substrate by a liquid coating process under relatively mild conditions. The relatively mild conditions include temperatures below 225.degree. C. and pressures above 9.4 mb. In an exemplary embodiment, a solution of diethyl aluminum ethoxide in anhydrous diglyme is applied to a flexible solid substrate by slot-die coating at ambient atmospheric pressure, and the diglyme removed by evaporation. An AlO.sub.x layer is formed by subjecting material remaining on the solid substrate to a relatively mild oven temperature of approximately 150.degree. C. The resulting AlO.sub.x layer exhibits relatively high light transmittance and relatively low vapor transmission rates for water. An exemplary embodiment of a flexible solid substrate is polyethylene napthalate (PEN). The PEN is not substantially adversely affected by exposure to 150.degree. C

Biosurfactant-enhanced hydrogen production from organic fraction of municipal solid waste using co-culture of E. coli and Enterobacter aerogenes.

PubMed

Sharma, Preeti; Melkania, Uma

2017-11-01

The effect of biosurfactants (surfactin and saponin) on the hydrogen production from organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. The biosurfactants were applied in the concentration ranges of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 5.0% each. Cumulative hydrogen production (P), maximum hydrogen production rate (Rmax) and lag phases (λ) were analyzed using modified Gompertz model. Results revealed that both the biosurfactants were effective in hydrogen production enhancement. The maximum cumulative hydrogen production of 743.5±14.4ml and 675.6±12.1ml and volumetric hydrogen production of 2.12L H2 /L substrate and 1.93L H2 /L substrate was recorded at 3.5% surfactin and 3.0% saponin respectively. Corresponding highest hydrogen yields were 79.2mlH 2 /gCarbo initial and 72.0mlH 2 /gCarbo initial respectively. Lag phase decreased from 12.5±2.0h at control to a minimum of 9.0±2.8h and 9.5±2.1h at 3.5% surfactin and 3.0% saponin respectively. Volatile fatty acid generation was increased with biosurfactants addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solid state photosensitive devices which employ isolated photosynthetic complexes

DOEpatents

Peumans, Peter; Forrest, Stephen R.

2009-09-22

Solid state photosensitive devices including photovoltaic devices are provided which comprise a first electrode and a second electrode in superposed relation; and at least one isolated Light Harvesting Complex (LHC) between the electrodes. Preferred photosensitive devices comprise an electron transport layer formed of a first photoconductive organic semiconductor material, adjacent to the LHC, disposed between the first electrode and the LHC; and a hole transport layer formed of a second photoconductive organic semiconductor material, adjacent to the LHC, disposed between the second electrode and the LHC. Solid state photosensitive devices of the present invention may comprise at least one additional layer of photoconductive organic semiconductor material disposed between the first electrode and the electron transport layer; and at least one additional layer of photoconductive organic semiconductor material, disposed between the second electrode and the hole transport layer. Methods of generating photocurrent are provided which comprise exposing a photovoltaic device of the present invention to light. Electronic devices are provided which comprise a solid state photosensitive device of the present invention.

Highly efficient and stable ultraviolet photocathode based on nanodiamond particles

NASA Astrophysics Data System (ADS)

Velardi, L.; Valentini, A.; Cicala, G.

2016-02-01

Nanodiamond (ND) layers on silicon substrate are deposited by the pulsed spray technique starting from nanoparticles of about 250 nm dispersed in 1,2-dichloroethane solvent. The aim of this letter is to investigate the quantum efficiency (QE) of photocathodes based on ND particles in the vacuum ultraviolet spectral range. Various ND layers are examined employing as-received and hydrogenated nanoparticles. As expected, the hydrogen plasma treatment improves strongly the photoemission of the layer giving a QE of 22% at 146 nm. Indeed, this efficiency value is achieved only if the particles are treated in H2 microwave plasma before the growth of the sprayed layer rather than to hydrogenate the already formed one. These QE values are higher than those of photocathodes based on plasma chemical vapor deposition diamond films, but with the advantage of being much stable, too. The highest QE values are explained to be due to the intrinsic chemical and structural features of utilized ND particles.

Release properties of tannic acid from hydrogen bond driven antioxidative cellulose nanofibrous films.

PubMed

Zhou, Bin; Hu, Xiaoqian; Zhu, Jinjin; Wang, Zhenzhen; Wang, Xichang; Wang, Mingfu

2016-10-01

Layer-by-layer (LBL) assembled films have been exploited for surface-mediated bioactive compound delivery. Here, an antioxidative hydrogen-bonded multilayer electrospun nanofibrous film was fabricated from tannic acid (TA), acting as a polyphenolic antioxidant, and poly(ethylene glycol) (PEG) via layer-by-layer assembly. It overcame the burst release behavior of nanofibrous carrier, due to the reversible/dynamic nature of hydrogen bond, which was responded to external stimuli. The PEG/TA nanofibrous films disassembled gradually and released TA to the media, when soaked in aqueous solutions. The release rate of TA increased with increasing bilayer number, pH and temperature, but decreased with enhancing ionic strength. The surface morphology of the nanofibrous mats was observed by scanning electron microscopy (SEM). The following antioxidant activity assay revealed that it could scavenge DPPH free radicals and ABTS(+) cation radicals, a major biological activity of polyphenols. This technology can be used to fabricate other phenolic-containing slowly releasing antioxidative nanofibrous films. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrochemical Visualization of Intracellular Hydrogen Peroxide at Single Cells.

PubMed

He, Ruiqin; Tang, Huifen; Jiang, Dechen; Chen, Hong-yuan

2016-02-16

In this Letter, the electrochemical visualization of hydrogen peroxide inside one cell was achieved first using a comprehensive Au-luminol-microelectrode and electrochemiluminescence. The capillary with a tip opening of 1-2 μm was filled with the mixture of chitosan and luminol, which was coated with the thin layers of polyvinyl chloride/nitrophenyloctyl ether (PVC/NPOE) and gold as the microelectrode. Upon contact with the aqueous hydrogen peroxide, hydrogen peroxide and luminol in contact with the gold layer were oxidized under the positive potential resulting in luminescence for the imaging. Due to the small diameter of the electrode, the microelectrode tip was inserted into one cell and the bright luminescence observed at the tip confirmed the visualization of intracellular hydrogen peroxide. The further coupling of oxidase on the electrode surface could open the field in the electrochemical imaging of intracellular biomolecules at single cells, which benefited the single cell electrochemical detection.

dl-Asparaginium nitrate

PubMed Central

Moussa Slimane, Nabila; Cherouana, Aouatef; Bendjeddou, Lamia; Dahaoui, Slimane; Lecomte, Claude

2009-01-01

In the title compound, C4H9N2O3 +·NO3 −, alternatively called (1RS)-2-carbamoyl-1-carboxy­ethanaminium nitrate, the asymmetric unit comprises one asparaginium cation and one nitrate anion. The strongest cation–cation O—H⋯O hydrogen bond in the structure, together with other strong cation–cation N—H⋯O hydrogen bonds, generates a succession of infinite chains of R 2 2(8) rings along the b axis. Additional cation–cation C—H⋯O hydrogen bonds link these chains into two-dimensional layers formed by alternating R 4 4(24) and R 4 2(12) rings. Connections between these layers are provided by the strong cation–anion N—H⋯O hydrogen bonds, as well as by one weak C—H⋯O inter­action, thus forming a three-dimensional network. Some of the cation–anion N—H⋯O hydrogen bonds are bifurcated of the type D—H⋯(A 1,A 2). PMID:21577586

Surface properties of hydrogenated nanodiamonds: a chemical investigation.

PubMed

Girard, H A; Petit, T; Perruchas, S; Gacoin, T; Gesset, C; Arnault, J C; Bergonzo, P

2011-06-28

Hydrogen terminations (C-H) confer to diamond layers specific surface properties such as a negative electron affinity and a superficial conductive layer, opening the way to specific functionalization routes. For example, efficient covalent bonding of diazonium salts or of alkene moieties can be performed on hydrogenated diamond thin films, owing to electronic exchanges at the interface. Here, we report on the chemical reactivity of fully hydrogenated High Pressure High Temperature (HPHT) nanodiamonds (H-NDs) towards such grafting, with respect to the reactivity of as-received NDs. Chemical characterizations such as FTIR, XPS analysis and Zeta potential measurements reveal a clear selectivity of such couplings on H-NDs, suggesting that C-H related surface properties remain dominant even on particles at the nanoscale. These results on hydrogenated NDs open up the route to a broad range of new functionalizations for innovative NDs applications development. This journal is © the Owner Societies 2011

Reduction of friction stress of ethylene glycol by attached hydrogen ions

PubMed Central

Li, Jinjin; Zhang, Chenhui; Deng, Mingming; Luo, Jianbin

2014-01-01

In the present work, it is shown that the friction stress of ethylene glycol can decrease by an order of magnitude to achieve superlubricity if there are hydrogen ions attached on the friction surfaces. An ultra-low friction coefficient (μ = 0.004) of ethylene glycol between Si3N4 and SiO2 can be obtained with the effect of hydrogen ions. Experimental result indicates that the hydrogen ions adsorbed on the friction surfaces forming a hydration layer and the ethylene glycol in the contact region forming an elastohydrodynamic film are the two indispensable factors for the reduction of friction stress. The mechanism of superlubricity is attributed to the extremely low shear strength of formation of elastohydrodynamic film on the hydration layer. This finding may introduce a new approach to reduce friction coefficient of liquid by attaching hydrogen ions on friction surfaces. PMID:25428584

Ortho-para-hydrogen equilibration on Jupiter

NASA Technical Reports Server (NTRS)

Carlson, Barbara E.; Lacis, Andrew A.; Rossow, William B.

1992-01-01

Voyager IRIS observations reveal that the Jovian para-hydrogen fraction is not in thermodynamic equilibrium near the NH3 cloud top, implying that a vertical gradient exists between the high-temperature equilibrium value of 0.25 at depth and the cloud top values. The height-dependent para-hydrogen profile is obtained using an anisotropic multiple-scattering radiative transfer model. A vertical correlation is found to exist between the location of the para-hydrogen gradient and the NH3 cloud, strongly suggesting that paramagnetic conversion on NH3 cloud particle surfaces is the dominant equilibration mechanism. Below the NH3 cloud layer, the para fraction is constant with depth and equal to the high-temperature equilibrium value of 0.25. The degree of cloud-top equilibration appears to depend on the optical depth of the NH3 cloud layer. Belt-zone variations in the para-hydrogen profile seem to be due to differences in the strength of the vertical mixing.

Thermal Hydraulics Design and Analysis Methodology for a Solid-Core Nuclear Thermal Rocket Engine Thrust Chamber

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Canabal, Francisco; Chen, Yen-Sen; Cheng, Gary; Ito, Yasushi

2013-01-01

Nuclear thermal propulsion is a leading candidate for in-space propulsion for human Mars missions. This chapter describes a thermal hydraulics design and analysis methodology developed at the NASA Marshall Space Flight Center, in support of the nuclear thermal propulsion development effort. The objective of this campaign is to bridge the design methods in the Rover/NERVA era, with a modern computational fluid dynamics and heat transfer methodology, to predict thermal, fluid, and hydrogen environments of a hypothetical solid-core, nuclear thermal engine the Small Engine, designed in the 1960s. The computational methodology is based on an unstructured-grid, pressure-based, all speeds, chemically reacting, computational fluid dynamics and heat transfer platform, while formulations of flow and heat transfer through porous and solid media were implemented to describe those of hydrogen flow channels inside the solid24 core. Design analyses of a single flow element and the entire solid-core thrust chamber of the Small Engine were performed and the results are presented herein

Conceptual Launch Vehicles Using Metallic Hydrogen Propellant

NASA Astrophysics Data System (ADS)

Cole, John W.; Silvera, Isaac F.; Foote, John P.

2008-01-01

Solid molecular hydrogen is predicted to transform into an atomic solid with metallic properties under pressures >4.5 Mbar. Atomic metallic hydrogen is predicted to be metastable, limited by some critical temperature and pressure, and to store very large amounts of energy. Experiments may soon determine the critical temperature, critical pressure, and specific energy availability. It is useful to consider the feasibility of using metastable atomic hydrogen as a rocket propellant. If one assumes that metallic hydrogen is stable at usable temperatures and pressures, and that it can be affordably produced, handled, and stored, then it may be a useful rocket propellant. Assuming further that the available specific energy can be determined from the recombination of the atoms into molecules (216 MJ/kg), then conceptual engines and launch vehicle concepts can be developed. Under these assumptions, metallic hydrogen would be a revolutionary new rocket fuel with a theoretical specific impulse of 1700 s at a chamber pressure of 100 atm. A practical problem that arises is that rocket chamber temperatures may be too high for the use of this pure fuel. This paper examines an engine concept that uses liquid hydrogen or water as a diluent coolant for the metallic hydrogen to reduce the chamber temperature to usable values. Several launch vehicles are then conceptually developed. Results indicate that if metallic hydrogen is experimentally found to have the properties assumed in this analysis, then there are significant benefits. These benefits become more attractive as the chamber temperatures increase.

Polyimide Precursor Solid Residuum

NASA Technical Reports Server (NTRS)

Weiser, Erik S. (Inventor); St.Clair, Terry L. (Inventor); Echigo, Yoshiaki (Inventor); Kaneshiro, Hisayasu (Inventor)

2001-01-01

A polyimide precursor solid residuum is an admixture of an aromatic dianhydride or derivative thereof and an aromatic diamine or derivative thereof plus a complexing agent, which is complexed with the admixture by hydrogen bonding. The polyimide precursor solid residuum is effectively employed in the preparation of polyimide foam and the fabrication of polyimide foam structures.

A hydrogen leak-tight, transparent cryogenic sample container for ultracold-neutron transmission measurements

NASA Astrophysics Data System (ADS)

Döge, Stefan; Hingerl, Jürgen

2018-03-01

The improvement of the number of extractable ultracold neutrons (UCNs) from converters based on solid deuterium (sD2) crystals requires a good understanding of the UCN transport and how the crystal's morphology influences its transparency to the UCNs. Measurements of the UCN transmission through cryogenic liquids and solids of interest, such as hydrogen (H2) and deuterium (D2), require sample containers with thin, highly polished and optically transparent windows and a well defined sample thickness. One of the most difficult sealing problems is that of light gases like hydrogen and helium at low temperatures against high vacuum. Here we report on the design of a sample container with two 1 mm thin amorphous silica windows cold-welded to aluminum clamps using indium wire gaskets, in order to form a simple, reusable, and hydrogen-tight cryogenic seal. The container meets the above-mentioned requirements and withstands up to 2 bar hydrogen gas pressure against isolation vacuum in the range of 10-5 to 10-7 mbar at temperatures down to 4.5 K. Additionally, photographs of the crystallization process are shown and discussed.

Large Scale Production of Densified Hydrogen Using Integrated Refrigeration and Storage

NASA Technical Reports Server (NTRS)

Notardonato, William U.; Swanger, Adam Michael; Jumper, Kevin M.; Fesmire, James E.; Tomsik, Thomas M.; Johnson, Wesley L.

2017-01-01

Recent demonstration of advanced liquid hydrogen storage techniques using Integrated Refrigeration and Storage (IRAS) technology at NASA Kennedy Space Center led to the production of large quantities of solid densified liquid and slush hydrogen in a 125,000 L tank. Production of densified hydrogen was performed at three different liquid levels and LH2 temperatures were measured by twenty silicon diode temperature sensors. System energy balances and solid mass fractions are calculated. Experimental data reveal hydrogen temperatures dropped well below the triple point during testing (up to 1 K), and were continuing to trend downward prior to system shutdown. Sub-triple point temperatures were seen to evolve in a time dependent manner along the length of the horizontal, cylindrical vessel. Twenty silicon diode temperature sensors were recorded over approximately one month for testing at two different fill levels (33 67). The phenomenon, observed at both two fill levels, is described and presented detailed and explained herein., and The implications of using IRAS for energy storage, propellant densification, and future cryofuel systems are discussed.

Symmetrical solid oxide fuel cells with impregnated SrFe0.75Mo0.25O3-δ electrodes

NASA Astrophysics Data System (ADS)

Meng, Xie; Liu, Xuejiao; Han, Da; Wu, Hao; Li, Junliang; Zhan, Zhongliang

2014-04-01

Here we report nominally symmetrical solid oxide fuel cells that feature thin La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) electrolytes and impregnated SrFe0.75Mo0.25O3-δ (SFMO)-LSGM composite electrodes. Operation on hydrogen fuels and air oxidants can produce maximum power densities of 0.39 W cm-2 at 650 °C and 0.97 W cm-2 at 800 °C. Impedance measurements indicate that the anode and the cathode polarizations are 0.22 and 0.04 Ω cm2 at 800 °C, respectively. Hydrogen partial pressure and temperature dependence of impedance data in humidified hydrogen shows that hydrogen oxidation kinetics is largely determined by hydrogen adsorption on the SFMO catalysts at high temperatures and charge transfer reactions along the SFMO|LSGM interfaces at low temperatures. Carbon tolerance of the present fuel cells is also examined in iso-octane fuels balanced by nitrogen at 800 °C that yields stable maximum power densities of 0.39 W cm-2.

Hydrogen generation from deliquescence of ammonia borane using Ni-Co/r-GO catalyst

NASA Astrophysics Data System (ADS)

Chou, Chang-Chen; Chen, Bing-Hung

2015-10-01

Hydrogen generation from the catalyzed deliquescence/hydrolysis of ammonia borane (AB) using the Ni-Co catalyst supported on the graphene oxide (Ni-Co/r-GO catalyst) under the conditions of limited water supply was studied with the molar feed ratio of water to ammonia borane (denoted as H2O/AB) at 2.02, 3.97 and 5.93, respectively. The conversion efficiency of ammonia borane to hydrogen was estimated both from the cumulative volume of the hydrogen gas generated and the conversion of boron chemistry in the hydrolysates analyzed by the solid-state 11B NMR. The conversion efficiency of ammonia borane could reach nearly 100% under excess water dosage, that is, H2O/AB = 3.97 and 5.93. Notably, the hydrogen storage capacity could reach as high as 6.5 wt.% in the case with H2O/AB = 2.02. The hydrolysates of ammonia borane in the presence of Ni-Co/r-GO catalyst were mainly the mixture of boric acid and metaborate according to XRD, FT-IR and solid-state 11B NMR analyses.

Behavior of tritium permeation induced by water corrosion of alpha iron around room temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Otsuka, T.; Hashizume, K.

2015-03-15

Tritium (T) permeation leakage to surroundings is a great safety concern in fission and fusion reactor systems. T permeation potentially occurs from T contaminated water through cooling tubes or storage tank made of metals which dissolve some T evolved by water corrosion. In order to understand behaviors of hydrogen uptake and permeation in pure α-iron (αFe) during water corrosion around room temperature, hydrogen permeation experiments for an αFe membrane have been conducted by means of tritium tracer techniques. The present study suggests that hydrogen produced by water corrosion of αFe is trapped in product oxide layers to delay hydrogen uptakemore » in αFe for a moment. However, the oxide layers do not work as a sufficient barrier for hydrogen uptake. Some of hydrogen dissolved in αFe normally diffuses and permeates through the bulk in the early stage of permeation. In a later stage, hydrogen permeation could be apparently stopped by the disappearance of concentration difference of tritium. Hydrogen partial pressure at the water/αFe interface could be ranged from 0.7 to 9.5 kPa around room temperature.« less

The role of surface oxides on hydrogen sorption kinetics in titanium thin films

NASA Astrophysics Data System (ADS)

Hadjixenophontos, Efi; Michalek, Lukas; Roussel, Manuel; Hirscher, Michael; Schmitz, Guido

2018-05-01

Titanium is presently discussed as a catalyst to accelerate the hydrogenation kinetics of hydrogen storage materials. It is however known that H absorption in Ti decisively depends on the surface conditions (presence or absence of the natural surface oxide). In this work, we use Ti thin films of controlled thickness (50-800 nm) as a convenient tool for quantifying the atomic transport. XRD and TEM investigations allow us to follow the hydrogenation progress inside the film. Hydrogenation of TiO2/Ti bi-layers is studied at 300 °C, for different durations (10 s to 600 min) and at varying pressures of pure H2 atmosphere. Under these conditions, the hydrogenation is found to be linear in time. By comparing films with and without TiO2, as well as by studying the pressure dependence of hydrogenation, it is demonstrated that hydrogen transport across the oxide represents the decisive kinetic barrier rather than the splitting of H2 molecules at the surface. Hydrogenation appears by a layer-like reaction initiated by heterogeneous nucleation at the backside interface to the substrate. The linear growth constant and the H diffusion coefficient inside the oxide are quantified, as well as a reliable lower bound to the hydrogen diffusion coefficient in Ti is derived. The pressure dependence of hydrogen absorption is quantitatively modelled.

Modelling of adsorption and intercalation of hydrogen on/into tungsten disulphide multilayers and multiwall nanotubes.

PubMed

Martínez, José I; Laikhtman, Alex; Moon, Hoi Ri; Zak, Alla; Alonso, Julio A

2018-05-07

Understanding the interaction of hydrogen with layered materials is crucial in the fields of sensors, catalysis, fuel cells and hydrogen storage, among others. Density functional theory, improved by the introduction of van der Waals dispersion forces, provides an efficient and practical workbench to investigate the interaction of molecular and atomic hydrogen with WS 2 multilayers and nanotubes. We find that H 2 physisorbs on the surface of those materials on top of W atoms, while atomic H chemisorbs on top of S atoms. In the case of nanotubes, the chemisorption strength is sensitive to the nanotube diameter. Diffusion of H 2 on the surface of WS 2 encounters quite small activation barriers whose magnitude helps to explain previous and new experimental results for the observed dependence of the hydrogen concentration with temperature. Intercalation of H 2 between adjacent planar WS 2 layers reveals an endothermic character. Intercalating H atoms is energetically favorable, but the intercalation energy does not compensate for the cost of dissociating the molecules. When H 2 molecules are intercalated between the walls of a double wall nanotube, the rigid confinement induces the dissociation of the confined molecules. A remarkable result is that the presence of a full H 2 monolayer adsorbed on top of the first WS 2 layer of a WS 2 multilayer system strongly facilitates the intercalation of H 2 between WS 2 layers underneath. This opens up an additional gate to intercalation processes.

1H, 13C, 15N NMR analysis of sildenafil base and citrate (Viagra) in solution, solid state and pharmaceutical dosage forms.

PubMed

Wawer, Iwona; Pisklak, Maciej; Chilmonczyk, Zdzisław

2005-08-10

Sildenafil citrate (SC) (Viagra) and sildenafil base in pure form are easily and unequivocally characterized by multinuclear NMR spectroscopy. Analysis of chemical shifts indicates that: (i) N6-H forms intramolecular hydrogen bonds, (ii) N25 is protonated in the salt and (iii) intermolecular OH...N hydrogen bonds involving N2 and N4 are present in the solid sildenafil citrate. 13C CPMAS NMR method has been proposed for the identification and quantitation of Viagra in its pharmaceutical formulations.

Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa.

PubMed

Eggert, J H; Karmon, E; Hemley, R J; Mao, A; Goncharov, A F

1999-10-26

We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway.

Methods for improved growth of group III nitride semiconductor compounds

DOEpatents

Melnik, Yuriy; Chen, Lu; Kojiri, Hidehiro

2015-03-17

Methods are disclosed for growing group III-nitride semiconductor compounds with advanced buffer layer technique. In an embodiment, a method includes providing a suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. The method includes forming an AlN buffer layer by flowing an ammonia gas into a growth zone of the processing chamber, flowing an aluminum halide containing precursor to the growth zone and at the same time flowing additional hydrogen halide or halogen gas into the growth zone of the processing chamber. The additional hydrogen halide or halogen gas that is flowed into the growth zone during buffer layer deposition suppresses homogeneous AlN particle formation. The hydrogen halide or halogen gas may continue flowing for a time period while the flow of the aluminum halide containing precursor is turned off.

Carbon Dioxide-Free Hydrogen Production with Integrated Hydrogen Separation and Storage.

PubMed

Dürr, Stefan; Müller, Michael; Jorschick, Holger; Helmin, Marta; Bösmann, Andreas; Palkovits, Regina; Wasserscheid, Peter

2017-01-10

An integration of CO 2 -free hydrogen generation through methane decomposition coupled with hydrogen/methane separation and chemical hydrogen storage through liquid organic hydrogen carrier (LOHC) systems is demonstrated. A potential, very interesting application is the upgrading of stranded gas, for example, gas from a remote gas field or associated gas from off-shore oil drilling. Stranded gas can be effectively converted in a catalytic process by methane decomposition into solid carbon and a hydrogen/methane mixture that can be directly fed to a hydrogenation unit to load a LOHC with hydrogen. This allows for a straight-forward separation of hydrogen from CH 4 and conversion of hydrogen to a hydrogen-rich LOHC material. Both, the hydrogen-rich LOHC material and the generated carbon on metal can easily be transported to destinations of further industrial use by established transport systems, like ships or trucks. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Organosulfide-plasticized solid-electrolyte interphase layer enables stable lithium metal anodes for long-cycle lithium-sulfur batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Guoxing; Gao, Yue; He, Xin

Lithium metal is a promising anode candidate for the next-generation rechargeable battery due to its highest specific capacity (3860 mA h g -1) and lowest potential, but low Coulombic efficiency and formation of lithium dendrites hinder its practical application. Here, we report a self-formed flexible hybrid solid-electrolyte interphase layer through co-deposition of organosulfides/organopolysulfides and inorganic lithium salts using sulfur-containing polymers as an additive in the electrolyte. The organosulfides/organopolysulfides serve as “plasticizer” in the solid-electrolyte interphase layer to improve its mechanical flexibility and toughness. The as-formed robust solid-electrolyte interphase layers enable dendrite-free lithium deposition and significantly improve Coulombic efficiency (99% overmore » 400 cycles at a current density of 2mAcm -2). A lithium-sulfur battery based on this strategy exhibits long cycling life (1000 cycles) and good capacity retention. This study reveals an avenue to effectively fabricate stable solid-electrolyte interphase layer for solving the issues associated with lithium metal anodes.« less