Electrochemical Hydriding of Mg-Based Alloys

2011 ◽  
Vol 312-315 ◽  
pp. 882-887
Author(s):  
Dalibor Vojtěch ◽  
Vítězslav Knotek ◽  
Pavel Novák
Keyword(s):  
Hydrogen Storage ◽  
High Temperatures ◽  
Room Temperature ◽  
Hydrogen Atmosphere ◽  
The Other ◽  
High Hydrogen ◽  
Hydrogen Saturation ◽  
Other Hand ◽  
Mechanism And Kinetics ◽  
Storage Methods

Mg-based alloys are prospective materials for reversible hydrogen storage in the form of metallic hydrides. Usually, hydrogen saturation is carried out at high temperatures and high hydrogen pressures. This is the reason for the high cost of metallic hydrides in comparison with other hydrogen storage methods. Electrochemical hydriding, on the other hand, can be realized at room temperature. Moreover, this process does not need any hydrogen atmosphere. In the presented work, electrochemical hydriding of several Mg-Ni-Mm-based alloys (Mm = mishmetal) is performed. Hydriding efficiency, mechanism and kinetics are described. It is shown that the additions of Ni, Mm and the formation of eutectic structures support hydriding of alloys.

scholarly journals Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

2013 ◽  
Vol 9 ◽  
pp. 8-14 ◽  
Author(s):  
Yan Sun ◽  
Jing Sun ◽  
Chao-Guo Yan
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Room Temperature ◽  
The Other ◽  
Other Hand ◽  
Three Component Reaction ◽  
High Yields

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

Diversification of α–Ketoamides via Transamidation Reactions with Alkyl and Benzyl Amines at Room Temperature

2021 ◽  
Author(s):  
Shweta Singh ◽  
Sureshbabu Popuri ◽  
Qazi Mohammad Junaid ◽  
Sabiah Shahul Hameed ◽  
Jeyakumar Kandasamy
Keyword(s):  
Room Temperature ◽  
The Other ◽  
Alkyl Amines ◽  
Other Hand ◽  
Wide Range

A wide range of N-tosyl α–ketoamides underwent transamidation with various alkyl amines in the absence of catalyst, base, or additives. On the other hand, transamidation in N-Boc α–ketoamides is achieved...

scholarly journals Effects of Heating Rate on Formation of Globular and Acicular Austenite during Reversion from Martensite

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 266 ◽  
Author(s):  
Xianguang Zhang ◽  
Goro Miyamoto ◽  
Yuki Toji ◽  
Tadashi Furuhara
Keyword(s):  
Heating Rate ◽  
High Temperatures ◽  
The Other ◽  
Growth Mode ◽  
High Heating Rate ◽  
Heating Rates ◽  
Other Hand ◽  
High Heating ◽  
Martensite Matrix

The effects of heating rate on the formation of acicular and globular austenite during reversion from martensite in Fe–2Mn–1.5Si–0.3C alloy have been investigated. It was found that a low heating rate enhanced the formation of acicular austenite, while a high heating rate favored the formation of globular austenite. The growth of acicular γ was accompanied by the partitioning of Mn and Si, while the growth of globular γ was partitionless. DICTRA simulation revealed that there was a transition in growth mode from partitioning to partitionless for the globular austenite with an increase in temperature at high heating rate. High heating rates promoted a reversion that occurred at high temperatures, which made the partitionless growth of globular austenite occur more easily. On the other hand, the severer Mn enrichment into austenite at low heating rate caused Mn depletion in the martensite matrix, which decelerated the reversion kinetics in the later stage and suppressed the formation of globular austenite.

Capillary Densification of Hydrogen in Nanoporous, Amorphous Carbons

2006 ◽  
Vol 927 ◽  
Author(s):  
Steven R. Lustig ◽  
Mark Shiflett ◽  
David Corbin ◽  
Pratibha Gai ◽  
Konstantinos Kourtakis
Keyword(s):  
Hydrogen Storage ◽  
Amorphous Carbon ◽  
Capillary Condensation ◽  
Hydrogen Atmosphere ◽  
Hydrogen Treatment ◽  
Tem Analysis ◽  
High Hydrogen ◽  
Synthesis Conditions ◽  
Palladium Catalyzed ◽  
Comparison Of The Results

ABSTRACTWe have studied the effect of synthesis conditions on the nanostructure of advanced carbons that show moderate to high hydrogen storage. We have performed in situ studies of the dynamic pyrolysis of palladium catalyzed multifunctional polymers (MFP) in nitrogen environments, to understand the effect of process parameters and to utilize the results in the development of optimum nanostructures to meet the storage requirements. Carbon sorbents have been synthesized from polysaccharides including chitosan, chitin, and cellulose. Pyrolysis in a hydrogen atmosphere at 1373 K and 24 h has lead to microporous carbons with an optimum surface area and pore volume exceeding 2000 m2 g−1 and 2.0 cc g−1, respectively. Gravimetric microbalance studies indicate that these materials physically absorb hydrogen and store between 7 to 10 mass percent at 10 bar and 100 K. TEM micrographs indicate that the amorphous carbon shows additional ordering with prolonged hydrogen treatment from 2 to 24 h which has proven beneficial in increasing hydrogen storage. X-ray diffraction, TEM analysis, and porosimetry measurements also indicate that extending hydrogen exposure beyond 24 h leads to decreasing hydrogen storage due to the continuation of a loss in carbon relative to metal contaminants (P, Ca, Na) in the starting materials and increased crystallinity. Comparison of the results have shown that for advanced carbons derived from polymers or natural products treated with hydrogen at high temperatures, the optimum nanostructure is substantially disordered (turbostratic) graphite, whereas for materials derived from MFP, it is primarily amorphous carbon. The experiments have also revealed the optimum temperature region for storage where sorption/desorption curves show evidence of capillary condensation/densification.

scholarly journals An electric furnace for experiments in vacuo at temperatures

1912 ◽  
Vol 87 (598) ◽  
pp. 519-524
Keyword(s):  
High Temperatures ◽  
Electric Furnace ◽  
Cuprous Oxide ◽  
The Other ◽  
Resistance Furnace ◽  
Heterogeneous Equilibrium ◽  
Other Hand ◽  
Large Current ◽  
Dissociation Pressures ◽  
Reduction Of Oxides

This furnace was designed with a view to investigating at temperatures up to 1500° C. certain cases of heterogeneous equilibrium in which the equilibrium is defined by the pressure of the system. Instances are the dissociation of certain oxides, nitrides, and carbonates, and the reduction of oxides by carbon. The furnace could not be constructed of carbon, as carbon would react with some of the gases of which the pressure had to be measured, and also because it is almost impossible to remove the adsorbed gases from large quantities of carbon. Tubes of Royal Berlin porcelain in a platinum-wound resistance furnace may be used for temperatures up to 1200°, but at about this temperature they become soft, while the glaze runs and combines with any boat or other substance in the furnace. Tubes of silica are not suitable, because they are porous at high temperatures, and because they disintegrate owing to crystallisation taking place. It was decided to make the furnace of a platinum tube and to heat it by passing a large current through it. As some of the substances which it would be necessary to place in the furnace react with platinum, e. g . copper formed by the dissociation of cuprous oxide, it was necessary to make the furnace sufficiently large to take a boat or crucible of magnesia large enough to contain the reacting substance and thick enough to protect the tube. On the other hand, the tube ought to be as small as possible, in order that in determining the dissociation pressures all the charge should not be decomposed before the equilibrium is attained.

High Temperature Implantation in Graphite

1983 ◽  
Vol 27 ◽  
Author(s):  
G. Braunstein ◽  
B.S. Elman ◽  
M.S. Dresselhaus ◽  
G. Dresselhaus ◽  
T. Venkatesan
Keyword(s):  
High Temperature ◽  
Radiation Damage ◽  
High Temperatures ◽  
Room Temperature ◽  
Pyrolytic Graphite ◽  
Rutherford Backscattering ◽  
The Other ◽  
Highly Oriented Pyrolytic Graphite ◽  
Graphite Lattice ◽  
Partial Annealing

ABSTRACTIn previous studies it was found that when highly oriented pyrolytic graphite (HOPG) is implanted at room temperature, the damage caused by the implantation could be completely annealed by heating the sample to temperatures higher than ∼ 2500°C. However at these high temperatures, the implanted species was found to diffuse out of the sample, as evidenced by the disappearance of the impurity peak in the Rutherford backscattering (RBS) spectrum. If, on the other hand, the HOPG crystal was held at a high temperature (≥ 600°C) during the implantation, partial annealing could be observed. The present work further shows that it is possible to anneal the radiation damage and simultaneously to retain the implants in the graphite lattice by means of high temperature implantation (Ti ≥ 450°C) followed by annealing at 2300°C.

Letters to the Editor

PEDIATRICS ◽  
1973 ◽  
Vol 52 (2) ◽  
pp. 309-309
Author(s):  
C. Warren Bierman
Keyword(s):  
Room Temperature ◽  
Skin Testing ◽  
The Other ◽  
Letters To The Editor ◽  
Other Hand ◽  
Number Of Patients ◽  
Testing Solution

Dr. Bergner is quite correct in pointing out that skin testing with a freshly prepared penicillin solution will select out only about 30% of patients who are anaphylacticly sensitive to penicillin.1 On the other hand, the use of a sterile solution of benzylpenicillin diluted with alkaline buffered saline (pH 7.6) and permitted to stand at room temperature for at least two weeks appreciably increases the number of patients so detected.2 We would agree that the availability of a penicilloyl polylysine (PPL) testing solution and a stabilized minor determinent mixture (MDM) would greatly enhance the armamentarium of the clinician to detect anaphylactic sensitivity to penicillin.3

The Role of the Haemocytes in the Growth and Moulting of an Insect, Rhodnius Prolixus (Hemiptera)

1955 ◽  
Vol 32 (4) ◽  
pp. 649-663
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
High Temperatures ◽  
Blood Cells ◽  
Trypan Blue ◽  
Secretory Activity ◽  
Rhodnius Prolixus ◽  
Crystalline Material ◽  
The Other ◽  
Full Activity ◽  
Other Hand

Moulting in Rhodnius is greatly delayed by the injection of trypan blue, indian ink or iron saccharate, which are taken up by the phagocytic blood cells (amoebocytes). This delay occurs only when the injections are made during the first 3 days after feeding, not on the fourth day or later. On the fourth day after feeding the amoebocytes become filled with secretory vacuoles which restrict the uptake of indian ink or iron saccharate. When the amoebocytes are blocked by such injections within a day after feeding, the secretory activity of the thoracic gland is greatly reduced. This is proved histologically and experimentally. On the other hand, moulting induced by implantation of a fully active thoracic gland is not delayed by blocking the haemocytes. It is therefore concluded that some substance secreted by the haemocytes is necessary for the full activity of the thoracic glands. The crystalline hormone isolated by Butenandt & Karlson from the silkworm will induce moulting in the decapitated Rhodnius larva and in the isolated abdomen. Its action is not inhibited or delayed by the injection of indian ink or iron saccharate. This supports the conclusion that it is the product of the thoracic gland. Sublethal high temperatures will inhibit moulting in Rhodnius even when it is provided with abundant hormone by injection of the crystalline material or by joining in parabiosis with a moulting larva.

PRECOCIOUS TERMINATION OF “OBLIGATORY” DIAPAUSE IN FIELD-COLLECTED PUPAE OF ANTHERAEA POLYPHEMUS

1968 ◽  
Vol 100 (2) ◽  
pp. 134-139 ◽  
Author(s):  
A. Mansingh ◽  
B. N. Smallman
Keyword(s):  
Adult Development ◽  
Room Temperature ◽  
The Other ◽  
Mortality Factor ◽  
Natural Mortality ◽  
Antheraea Polyphemus ◽  
Other Hand ◽  
Heavy Mortality

AbstractAntheraea polyphemus Cramer pupae, collected in early August, were found to maintain adult development at room temperature and natural daylength of late August and early September. These pupae had almost no coldhardiness, and heavy mortality occurred in the group of pupae stored at 6 °C. On the other hand, the pupae of A. polyphemus collected in late September were in diapause and were perfectly coldhardy. The possible relationship between the date of pupation and the incidence of diapause, and its significance as a natural mortality factor, is discussed.

Economics of the Abrasive Cutoff Operation

1967 ◽  
Vol 89 (3) ◽  
pp. 514-518
Author(s):  
D. A. Farmer ◽  
M. C. Shaw
Keyword(s):  
Wear Rate ◽  
High Temperatures ◽  
Feed Rate ◽  
Minimum Cost ◽  
The Other ◽  
Minimum Rate ◽  
Other Hand ◽  
The Cost ◽  
Minimum Wear

A minimum rate of wear exists at a particular downfeed rate in the abrasive cutoff operation. When the feed rate is lower than this value, wear is excessive due to high temperatures in the outer portions of the wheel. On the other hand, when the feed rate is higher than the minimum wear rate value, wear is also excessive due to insufficient space between active grains to accommodate the chips. In practice, a feed rate somewhat higher than the mininum wear rate value should be chosen since this will correspond to minimum cost per cut. Methods of arriving at the cost optimum downfeed rate for the abrasive cutoff operation are presented, including special charts for use in the workshop.

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