scholarly journals 2-step reaction kinetics for hydrogen absorption into bulk material via dissociative adsorption on the surface

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Taro Yakabe ◽  
Gaku Imamura ◽  
Genki Yoshikawa ◽  
Naoya Miyauchi ◽  
Masahiro Kitajima ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Dynamic Process ◽  
Hydrogen Absorption ◽  
Hydrogen Pressure ◽  
Absorption Rate ◽  
Bulk Material ◽  
Dissociative Adsorption ◽  
The Other ◽  
Hyperbolic Function ◽  
Square Root

AbstractWe have demonstrated that the process of hydrogen absorption into a solid experimentally follows a Langmuir-type (hyperbolic) function instead of Sieverts law. This can be explained by independent two theories. One is the well-known solubility theory which is the basis of Sieverts law. It explains that the amount of hydrogen absorption can be expressed as a Langmuir-type (hyperbolic) function of the square root of the hydrogen pressure. We have succeeded in drawing the same conclusion from the other theory. It is a 2-step reaction kinetics (2sRK) model that expresses absorption into the bulk via adsorption on the surface. The 2sRK model has an advantage to the solubility theory: Since it can describe the dynamic process, it can be used to discuss both the amount of hydrogen absorption and the absorption rate. Some phenomena with absorption via adsorption can be understood in a unified manner by the 2sRK model.

The mechanism of the production of atomic hydrogen by hot tungsten

1936 ◽  
Vol 32 (4) ◽  
pp. 653-656 ◽  
Author(s):  
J. K. Roberts ◽  
G. Bryce
Keyword(s):  
Temperature Variation ◽  
Atomic Hydrogen ◽  
Hydrogen Molecule ◽  
Hydrogen Pressure ◽  
The Other ◽  
Square Root ◽  
Important Process ◽  
Experimental Conditions ◽  
Tungsten Atom ◽  
Tungsten Surface

The fact that the rate of production of atomic hydrogen at a tungsten surface at a given temperature is proportional to the square root of the hydrogen pressure means either that the important process is the evaporation of atoms from an adsorbed film which over the whole range of experimental conditions is sparsely occupied, or that the production of atoms is in the main due to a process in which a hydrogen molecule strikes a bare tungsten atom in the surface, one atom being adsorbed and the other evaporating and the surface being almost completely covered over the whole range of experimental conditions. Either process leads to a temperature variation in the rate of atom production in agreement with experiment. A definite decision between the two processes cannot yet be made.

scholarly journals Preparation of Mg2FeH6Nanoparticles for Hydrogen Storage Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
N. A. Niaz ◽  
I. Ahmad ◽  
N. R. Khalid ◽  
E. Ahmed ◽  
S. M. Abbas ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Absorption ◽  
Hydrogen Pressure ◽  
Absorption Rate ◽  
Desorption Kinetics ◽  
Prepared Compound ◽  
Hydrogen Storage Properties ◽  
Storage Properties ◽  
Effective Hydrogen ◽  
Type Apparatus

Magnesium (Mg) and iron (Fe) nanoparticles are prepared by thermal decomposition of bipyridyl complexes of metals. These prepared Mg-Fe (2 : 1) nanoparticles are hydrogenated under 4 MPa hydrogen pressure and 673 K for 48 hours to achieve Mg2FeH6. Their structural analysis was assessed by applying manifold techniques. The hydrogen storage properties of prepared compound were measured by Sieverts type apparatus. The desorption kinetics were measured by high pressure thermal desorption spectrometer (HP-TDS). More than 5 wt% hydrogen released was obtained by the Mg2FeH6within 5 min, and during rehydrogenation very effective hydrogen absorption rate was observed by the compound.

Characteristics of Hydrogen Absorption-Desorption Reaction in R-M (R=Y, La, Ce; M=Co, Rh, Ir, Ni, Pd, Pt) Binary Systems

2002 ◽  
Vol 753 ◽  
Author(s):  
H. Mizutani ◽  
K. Hirano ◽  
J. Kadono ◽  
S. Nishiuchi ◽  
S. Yamamoto ◽  
...  
Keyword(s):  
Hydrogen Concentration ◽  
Cohesive Energy ◽  
Hydrogen Absorption ◽  
Absorption Rate ◽  
Binary Systems ◽  
Electronic States ◽  
Experimental Results ◽  
The Other ◽  
Energy Fluctuation ◽  
Desorption Reaction

ABSTRACTThe amount of absorbed hydrogen, the absorption rate and the reversibility of hydrogen absorption-desorption reaction were measured for binary systems R-M (R= Y, La, Ce; M=Co, Rh, Ir, Ni, Pd, Pt). These experimental results were discussed by comparing the number of states unoccupied by electrons, the cohesive energy and the energy fluctuation, which were calculated by the extended Hückel method. The main results are as follows. (a) The more the number of unoccupied electronic states in the compounds, the more hydrogen is absorbed, (b) the critical concentrations of hydrogen in the R-M compounds where the energy fluctuation decreases remarkably correspond to the inflection or saturation points in the absorption curve, and (c) when the cohesive energy of a compound decreases linearly with hydrogen concentration, the compound easily desorbs hydrogen. On the other hand, when a sharp knickpoint is observed in the curve of cohesive energy - hydrogen concentration, the desorption reaction is hard to occur.

Suszeptibilitätsmessungen an Palladium/Wasserstoff

1969 ◽  
Vol 24 (1) ◽  
pp. 1-6 ◽  
Author(s):  
P. Brill ◽  
J. Voitländer
Keyword(s):  
Phase Transition ◽  
Hydrogen Absorption ◽  
Hydrogen Pressure ◽  
The Other ◽  
Palladium Black ◽  
Helical Springs ◽  
Β Phase ◽  
Faraday Method ◽  
Black Sample ◽  
Magnetic Balance

A magnetic balance using the Faraday method and quartz helical springs is described. The susceptibility of the Palladium hydrogen system is investigated within the temperature range from 50 °C to 100 °C. Hydrogen absorption and desorption of a Palladium black sample are caused by varying the hydrogen pressure. The susceptibility and the weight of the sample are observed con­tinuously and fairly near to the equilibrium PdHn/H2 as a function of pressure. The p (n) -isotherms show the well known hysteresis; on the other hand, the χ (n) -isotherms for absorption and desorp­tion coincide and there is no hysteresis. The χ- n relationship is independent of the a→β phase transition. Finally, the results of the susceptibility measurements are compared with the band struc­ture of Pd determined by Hoare and Yates.

Effect of hydrogen pressure on hydrogen absorption of waste Nd-Fe-B sintered magnets

2019 ◽  
Vol 473 ◽  
pp. 144-147 ◽  
Author(s):  
X.T. Li ◽  
M. Yue ◽  
S.X. Zhou ◽  
C.J. Kuang ◽  
G.Q. Zhang ◽  
...  
Keyword(s):  
Hydrogen Absorption ◽  
Hydrogen Pressure ◽  
Sintered Magnets

scholarly journals Efficacy of Fungicide Applications During and After Anthesis Against Fusarium Head Blight and Deoxynivalenol in Soft Red Winter Wheat

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1387-1397 ◽  
Author(s):  
D. L. D'Angelo ◽  
C. A. Bradley ◽  
K. A. Ames ◽  
K. T. Willyerd ◽  
L. V. Madden ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
The Other ◽  
Square Root ◽  
Head Blight ◽  
Soft Red Winter Wheat ◽  
Untreated Check ◽  
Red Winter Wheat ◽  
Days After Anthesis

Seven field experiments were conducted in Ohio and Illinois between 2011 and 2013 to evaluate postanthesis applications of prothioconazole + tebuconazole and metconazole for Fusarium head blight and deoxynivalenol (DON) control in soft red winter wheat. Treatments consisted of an untreated check and fungicide applications made at early anthesis (A), 2 (A+2), 4 (A+4), 5 (A+5), or 6 (A+6) days after anthesis. Six of the seven experiments were augmented with artificial Fusarium graminearum inoculum, and the other was naturally infected. FHB index (IND), Fusarium damaged kernels (FDK), and DON concentration of grain were quantified. All application timings led to significantly lower mean arcsine-square-root-transformed IND and FDK (arcIND and arcFDK) and log-transformed (logDON) than in the untreated check; however, arcIND, arcFDK, and logDON for the postanthesis applications were generally not significantly different from those for the anthesis applications. Relative to the check, A+2 resulted in the highest percent control for both IND and DON, 69 and 54%, respectively, followed by A+4 (62 and 52%), A+6 (62 and 48%), and A (56 and 50%). A+2 and A+6 significantly reduced IND by 30 and 14%, respectively, relative to the anthesis application. Postanthesis applications did not, however, reduce DON relative to the anthesis application. These results suggest that applications made up to 6 days following anthesis may be just as effective as, and sometimes more effective than, anthesis applications at reducing FHB and DON.

Serum Concentrations of Salicylic Acid following Topically Applied Salicylate Derivatives

1996 ◽  
Vol 30 (9) ◽  
pp. 935-940 ◽  
Author(s):  
Pina Morra ◽  
William R Bartle ◽  
Scott E Walker ◽  
S Nicole Lee ◽  
Susan K Bowles ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Rate Constant ◽  
Maximum Concentration ◽  
Methyl Salicylate ◽  
Absorption Rate ◽  
The Other ◽  
Pharmacokinetic Parameters ◽  
Absorption Rate Constant ◽  
Serum Concentrations ◽  
Women Volunteers

OBJECTIVE: To compare the rate and extent of systemic salicylate absorption following single and multiple applications of two topically applied analgesics, one containing methyl salicylate and the other containing trolamine salicylate. DESIGN: Two-period, two-treatment, randomized, crossover, multiple-dose study in healthy men and women volunteers. PARTICIPANTS: Six men and six women volunteers, 21–14 years of age. INTERVENTIONS: Subjects applied 5 g of an ointment containing 12.5% methyl salicylate twice daily for 4 days (8 doses) or a cream containing trolamine 10% twice daily for two doses, to a 10-cm2 area on the thigh. Treatment order and leg (right or left) were assigned randomly. Subjects were crossed over to the alternate treatment on the other leg after a minimum washout period of 7 days. MAIN OUTCOME MEASURES: The total amount of salicylate recovered in the urine during two dosing intervals (24 hours) on each study day, relative to the applied dose, was used to calculate the bioavailability of each product. Mean standard pharmacokinetic parameters including area under the curve, maximum concentration (Cmax), time to maximum concentration, and minimum concentrations at steady-state were determined from serum concentrations. Serum concentrations were fit to three pharmacokinetic models and the suitability of each model was evaluated. Estimates of absorption rate constant, clearance, volume, and fraction absorbed on day 1 were estimated by using the best-fitting model. RESULTS: Salicylic acid could not be detected in serum after trolamine application. However, concentrations between 0.31 and 0.91 mg/L were detected within 1 hour of the first application of methyl salicylate and Cmax, between 2 and 6 mg/L were observed following the seventh application on day 4. Both the extent and rate of absorption changed after the first 24 hours. The absorption rate constant increased significantly from the first to the seventh dose (first dose absorption rate constant: 0.16 h−1; seventh dose: 0.28 h−1; p < 0.035). Urinary recovery of total salicylate (salicylic acid and principal metabolites of salicylic acid) during the first 24 hours of the methyl salicylate phase averaged 175.2 mg, exceeding the 6.9 mg (p < 0.05) recovered during the trolamine phase. The recovery of salicylate in the urine in the first 24 hours after application of methyl salicylate was significantly greater than the 1.4% recovered after application of trolamine (p < 0.05). Furthermore, the fraction of methyl salicylate recovered in the urine increased significantly from 15.5% on day 1 to approximately 22% on the second, third, and fourth days. CONCLUSIONS: A considerable amount of salicylic acid may be absorbed through the skin after topical application of methyl salicylate products and this may increase with multiple applications. Caution is warranted in patients for whom systemic salicylate may be hazardous or problematic.

Hölderlins Homburger Folioheft in diachroner Darstellung

2021 ◽  
Vol 35 (1) ◽  
pp. 99-119
Author(s):  
Hans Gerhard Steimer
Keyword(s):  
Genetic Analysis ◽  
Dynamic Process ◽  
Print Media ◽  
Writing Process ◽  
Spatial Arrangement ◽  
The Other ◽  
Dynamic Evolution ◽  
Late Work ◽  
Gradual Process ◽  
Topographic Representation

Abstract Literary compositional drafts and working manuscripts preserve traces of the gradual process of writing and its different stages. In the static medium of print, genetic editions are confronted with the problem of depicting the dynamic evolution of texts. Presenting the variants in line-by-line synoptic display disregards the spatial arrangement on the manuscript pages. On the other hand, giving a topographic representation of the writing in diplomatic transcripts might stratify it into a few chronological layers but is unable to sufficiently reproduce the dynamic process to an elaborate degree. Consequently, the screen is better suited to visualise the writing process. The digital presentation of the ‘Homburg Folio’, the most important manuscript of Friedrich Hölderlin’s late work, offers not only the transcriptional record as known from print media but displays the process of writing and revision on each of the facsimile’s pages itself (https://homburgfolio.wlb-stuttgart.de). Thus, it is possible to visualise writing both as an act in time and its graphic result on the space of a page. It confines itself to the presentation of the genesis without any constitution of a text. The combination of these different operations has often led to errors. Decoupling the genetic analysis from the extrapolation of text reveals its potential.

Terrorism: Group dynamic and interdisciplinary aspects

2021 ◽  
pp. 79-94
Author(s):  
Thomas Wenzel ◽  
Reem Alksiri ◽  
Anthony F. Chen
Keyword(s):  
Human Rights ◽  
Transitional Justice ◽  
Dynamic Process ◽  
The Other ◽  
Dynamic Processes ◽  
Group Dynamic ◽  
Complex Background ◽  
Basic Concepts ◽  
Extreme Violence ◽  
Specific Impact

In this chapter, we offer an interdisciplinary and group-focused model to examine how extreme violence develops, and discuss aspects of interventions for prevention, specifically with regard to terrorism and its many forms. We argue that an analysis of terrorism must be more open, and include research into the perpetrators of extreme violence such as genocide. In general, we see the breakdown of empathy, a group dynamic process that creates the image of ‘the other’ and the violation of basic concepts of humanitarian and human rights laws, as a precondition to terrorism when viewed as a subtype of extreme violence. In recent years, Internet-based and large multinational groups have gained importance, a factor that is insufficiently considered, meaning that more attention is needed on group dynamic processes as drivers of extreme violence. Our interpretation uses models such as that developed by the group analyst Vamik Volkan, and others, including that of chosen trauma. We discuss these factors together with possible strategies to aid transitional justice and contribute to the rehabilitation of victims and perpetrators. The specific impact of each act of terrorism and the needs of victims and society to recover reflect the complex background of each event, and of the contexts in which the crimes were committed.

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