Reaction Rate of Liquid-Quenchied Water-Floating Alloy

1994 ◽  
Vol 362 ◽  
Author(s):  
T. Aida ◽  
Y. Nishi
Keyword(s):  
Activation Energy ◽  
Specific Gravity ◽  
Apparent Activation Energy ◽  
Reaction Rate ◽  
Water Diffusion ◽  
Hydrogen Gas ◽  
The Other ◽  
Al Alloy ◽  
Other Hand ◽  
Early Reaction

AbstractWe investigate a reaction rate of Mg-Li Al alloy (specific gravity is 0.95) in water. The hydrogen gas is mainly generated as follows : Li + H2O → LiOH + 1/2 H2 ↑. Using the volume of hydrogen gas, the reaction rate is estimated. The apparent activation energy (E) is 4.63 kcal/mol for the early reaction period. It is approximately equal to that of the water diffusion. On the other hand, the E is 9 kcal/mol after the early reaction period at the 2 ml (the volume of hydrogen gas). Furthermore, we succeed to prevent the sample against the reaction by the use of coating paints.

Organic Sulfides and Polysulfides. III. Reactions with Amines

1958 ◽  
Vol 31 (3) ◽  
pp. 615-617 ◽  
Author(s):  
Yuji Minoura
Keyword(s):  
Aromatic Amines ◽  
Glycolic Acid ◽  
Reaction Rate ◽  
Thioglycolic Acid ◽  
The Other ◽  
Relative Ease ◽  
Organic Sulfides ◽  
Other Hand ◽  
Organic Polysulfides

Abstract 1. Mono-, di-, and trimethylamine when treated with benzyl and tolyl mercaptan give disufides ; on the other hand, thioglycolic acid gives the monosulfide. 2. Aniline and diphenylamine do not react with mercaptans or organic sulfides. 3. Mono-, di- and trimethylamine react with organic polysulfides. The tri- and tetrasulfides of the tolyl and benzyl series give disulfides by desulfurization. The glycolic acud sulfides are desulfurized to monosulfide. 4. The relative desulfurization activities of mono-, di- and trimethylamine are (CH3)3N < CH3NH2 < (CH3)2NH. This order is the same as for the basicity of these amines. Aromatic amines, because of their weak basicity, do not react with organic polysulfides. 5. The relative ease of desulfurization is in the order glycolic acid > benzyl > tolyl. The more sulfur a polysulfide contains, the more readily it desulfurizes. The mercaptan to disulfide reaction rate is faster than desulfurization of polysulfides.

High Temperature Oxidation of SiC Powder in Oxidizing Atmosphere Containing Water Vapor

2008 ◽  
Vol 403 ◽  
pp. 197-200 ◽  
Author(s):  
T. Akashi ◽  
Miho Kasajima ◽  
Chiharu Muraoka ◽  
Hajime Kiyono
Keyword(s):  
Activation Energy ◽  
Water Vapor ◽  
Weight Gain ◽  
Apparent Activation Energy ◽  
High Temperature Oxidation ◽  
Oxidation Process ◽  
Water Vapor Pressure ◽  
The Other ◽  
Silica Layer ◽  
Temperature Oxidation

Oxidation of SiC powder was studied at 1373 K to 1873 K in Ar-O2, Ar-H2O, and Ar-O2-H2O using thermogravimetry. At 1373 K to 1573K, the weight gain increased with increasing water vapor pressure. The oxidation rate was evaluated on the basis of the Ginstering-Brounshtein kinetic model. In this temperature region, the apparent activation energy for the oxidation was almost the same (139-191 kJmol-1) independent of the atmosphere, suggesting that the same oxidation process proceeds. On the other hand, at temperatures >1673 K, the weight gain in the dry O2 (Ar-O2) was greater than that in the wet and wet O2 (Ar-H2O and Ar-O2-H2O). The apparent activation energy in the dry O2 (442 kJmol-1) was much greater than that in the wet and wet O2. We propose that water molecule diffused in silica layer in the wet and wet O2 atmosphere at 1373 K to 1873 K.

scholarly journals Instantaneous activation energy of alkali activated materials

2019 ◽  
Vol 3 ◽  
pp. 121-123
Author(s):  
Shiju Joseph ◽  
Siva Uppalapati ◽  
Ozlem Cizer
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Reaction Rate ◽  
Arrhenius Equation ◽  
Isothermal Calorimetry ◽  
Traditional Methods ◽  
Cement Based Materials ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Alkali Activated

Alkali activated materials (AAM) are generally cured at high temperatures to compensate for the low reaction rate. Higher temperature accelerates the reaction of AAM as in cement-based materials and this effect is generally predicted using Arrhenius equation based on the activation energy. While apparent activation energy is calculated from parallel isothermal calorimetry measurements at different temperatures, instantaneous activation energy is typically measured using a differential scanning calorimeter. Compared to the apparent activation energy, instantaneous activation energy has minimal effects on the microstructural changes due to the variation in temperature. In this work, the evolution of activation energy was determined by traditional methods and was compared with the instantaneous activation energy. It was found that while the activation energy changed with the progress of reaction over traditional methods, the instantaneous activation energy did not show any changes / or remained the same. The instantaneous activation energy was also found to be higher compared to the apparent activation energy determined with traditional methods.

scholarly journals Observations on the blood-corpuscles, particularly with reference to opinions expressed and conclusions drawn in papers ‘on the corpuscles of the blood,’ and ‘on fibre,’ recently published in the Philosophical Transactions

1843 ◽  
Vol 4 ◽  
pp. 431-432
Keyword(s):  
Mechanical Properties ◽  
Specific Gravity ◽  
The Other ◽  
Central Portion ◽  
Thick Wall ◽  
Altered State ◽  
Chemical Reagents ◽  
Other Hand ◽  
Double Contour

The author points out what he considers to be important errors in the series of papers by Dr. Martin Barry, which have lately appeared in the Philosophical Transactions, and are entitled, “ On the Corpuscles of the Blood ," and “ On Fibre ." He alleges that Dr. Barry has generally confounded the colourless corpuscles contained in the blood with the red corpuscles of the same fluid; each of which latter kind consists of a vesicle or cell, with thick walls, but in a collapsed and flattened state, and having therefore a biconcave form, and in consequence of its thick wall being doubled on itself, presenting under the microscope a broad circumferential ring, which is illuminated or shaded differently from the depressed central portion, according to the focal adjustment of the instrument: while the colourless corpuscles, on the other hand, are of a globular shape, strongly refractive of light, and granulated on their surface, and are of less specific gravity and of somewhat larger size than the red corpuscles. The author quotes various passages from Dr. Barry’s papers in proof of his assertions, and refers particularly to fig. 23 of his second paper on the corpuscles of the blood. He farther states, that Dr. Barry’s description of the appearances of what he terms the red corpuscles, in paragraphs 53, 68, and 76 of his second paper, can, in fact, apply only to the colourless corpuscles: and he observes, that even when Dr. Barry does, at last, in his “Additional Observations,” advert to the distinction between the red and the colourless globules, he considers the latter as being merely “the discs” contained in the red globules appearing under an altered state. The author regards as wholly erroneous the notion which Dr. Barry entertains that a fibre exists in the interior of the blood-cor­puscle; and that these fibres, after their escape from thence, constitute the fibres which are formed by the consolidation of the fibrin of the liquor sanguinis . The beaded aspect presented by the double contour of the thick wall of the red corpuscle when it has been acted upon either by mechanical causes or by chemical reagents, of which the effect is to corrugate the edge, and to bend it alternately in opposite directions, has, in the opinion of the author, given rise to the illusive appearance of an internal, annular fibre. The appearance of flask-like vesicles presented by some of the red corpuscles, with the alleged fibre protruding from their neck, the author ascribes altogether to the effects of decomposition, which has altered the mechanical properties of the corpuscle, and allowed it to be drawn out, like any other viscid matter, into a thread.

Note on the Beads found embedded in the top of the Two-foot Peat-bed (E) at St. Germans, near King’s Lynn.

1933 ◽  
Vol 70 (4) ◽  
pp. 180-182 ◽  
Author(s):  
Horace C. Beck
Keyword(s):  
Specific Gravity ◽  
Glass Bead ◽  
Small Difference ◽  
Early Period ◽  
The Other ◽  
Other Hand ◽  
La Tène ◽  
The Mediterranean ◽  
La Tene

Seven beads were found, details of which are given below:—Bead No. 1.—Pale cobalt-coloured annular glass bead. Weight, 5·21 g.; sp. gr., 2·412. There are two varieties of this bead which are very similar: one is of the La Tene period, and the other is Saxon. There has been a small difference of specific gravity in practically all the specimens I have examined, but it is so slight that I do not think it is safe to trust as a means of dating them. At the same time it has been fairly consistent, as in twelve specimens from different sites dated to the early period in Britain, France, and the Mediterranean the specific gravity has been below 2·46, and the only other early specimen I have tested was 2·485. On the other hand, all the beads that I have tested which I know to be Saxon have a specific gravity of 2·485 or over. I have, however, recently seen a bead from Lincolnshire with the same specific gravity as this No. 1, which, I think, is probably Saxon. Blue annular Saxon beads of this type, but usually smaller, are more common in the eastern counties than in any other part of England.

scholarly journals The State of Water in Human and Dog Red Cell Membranes

1970 ◽  
Vol 55 (4) ◽  
pp. 451-466 ◽  
Author(s):  
F. L. Vieira ◽  
R. I. Sha'afi ◽  
A. K. Solomon
Keyword(s):  
Activation Energy ◽  
Cell Membrane ◽  
Apparent Activation Energy ◽  
Water Diffusion ◽  
Red Cells ◽  
Red Cell ◽  
Kcal Mole ◽  
Red Cell Membrane ◽  
Temperature Range ◽  
Human Red Cells

The apparent activation energy for the water diffusion permeability coefficient, Pd, across the red cell membrane has been found to be 4.9 ± 0.3 kcal/mole in the dog and 6.0 ± 0.2 kcal/mole in the human being over the temperature range, 7° to 37°C. The apparent activation energy for the hydraulic conductivity, Lp, in dog red cells has been found to be 3.7 ± 0.4 kcal/mole and in human red cells, 3.3 ± 0.4 kcal/mole over the same temperature range. The product of Lp and the bulk viscosity of water, η, was independent of temperature for both dog and man which indicates that the geometry of the red cell membrane is not temperature-sensitive over our experimental temperature range in either species. In the case of the dog, the apparent activation energy for diffusion is the same as that for self-diffusion of water, 4.6–4.8 kcal/mole, which indicates that the process of water diffusion across the dog red cell membrane is the same as that in free solution. The slightly, but significantly, higher activation energy for water diffusion in human red cells is consonant with water-membrane interaction in the narrower equivalent pores characteristic of these cells. The observation that the apparent activation energy for hydraulic conductivity is less than that for water diffusion across the red cell membrane is characteristic of viscous flow and suggests that the flow of water across the membranes of these red cells under an osmotic pressure gradient is a viscous process.

Effect of Electroless Ni-P Plating on Mechanical Properties of Al-4%Ge Alloy

2016 ◽  
Vol 879 ◽  
pp. 897-902
Author(s):  
Teruto Kanadani ◽  
Norihito Nagata ◽  
Makoto Hino ◽  
Koji Murakami ◽  
Keitaro Horikawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Aging Treatment ◽  
Hydrogen Desorption ◽  
Hydrogen Gas ◽  
The Other ◽  
Breaking Elongation ◽  
Other Hand ◽  
Stress Region ◽  
Electroless Ni

In this study, the effect of electroless Ni-P plating on the mechanical properties of Al-4%Ge alloy was investigated. As the results, the following points were clarified. (i) Tensile strength of the specimen subjected to the Ni-P plating after aging treatment or furnace cooling treatment was improved by about 10% in comparison to one of the non-processed specimens. (ii) Breaking elongation of the specimen subjected to the Ni-P plating after aging treatment showed no significant changes in comparison to one of the non-processed specimens. On the other hand, breaking elongation of the specimen subjected to Ni-P plating after a furnace cooling treatment was reduced to 70% in comparison to one of the non-processed specimens. (iii) Fatigue strength of the specimen subjected to the Ni-P plating after a furnace cooling treatment was overall reduced rather than one of non-processed specimens. (iv) Fatigue strength of the specimen subjected to the Ni-P plating after aging treatment was overall reduced, except for the low-stress region, rather than one of the non-processed specimens. (v) In the specimen subjected to Ni-P plating after a furnace cooling treatment or aging treatment, clear hydrogen desorption was recognized. On the other hand, there was only hydrogen desorption from a few of the non-processed specimens. Especially, it is considered that the poor fatigue strength and ductility of the plating materials are mainly due to the interaction between the surface precipitates and hydrogen gas.

Reduction Kinetics of Bayan Obo Coexisted Iron and Niobium Ore by Carbon-Bearing Pellet

2011 ◽  
Vol 418-420 ◽  
pp. 346-352 ◽  
Author(s):  
Fu Shun Zhang ◽  
Zeng Wu Zhao ◽  
Yan Li ◽  
Nai Xiang Feng
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Reaction Rate ◽  
Mass Loss Rate ◽  
Reduction Process ◽  
Inert Atmosphere ◽  
Reaction Rate Constant ◽  
Carbon Gasification ◽  
Reaction Rate Constants ◽  
Two Stages

The mass loss rate of carbon-bearing pellet of coexisted iron and niobium ore during reduction process was investigated between 900 and 1050°C in inert atmosphere. The reduction mechanism was studied by analyzing reaction rate constant, apparent activation energy，and the controlling step. The results show that temperature has the significant effect on the reduction of carbon-bearing pellet. The reduction processes include the faster reaction stage and the slower reduction stage, and respective reaction rate constants in two stages are k1=exp (21.025-40484/(RT)) and k2= exp (21.060-42516/(RT))，while respective apparent activation energy are 337 and 353 KJ/mol. Both steps are controlled by carbon gasification.

Kinetics of Aqueous Alteration of P0798 Simulated Waste Glass in the Presence of Bentonite

2006 ◽  
Vol 932 ◽  
Author(s):  
K. Yamaguchi ◽  
Y. Inagaki ◽  
T. Saruwatari ◽  
K. Idemitsu ◽  
T. Arima ◽  
...  
Keyword(s):  
Secondary Phase ◽  
Model Analysis ◽  
Water Diffusion ◽  
Experimental Results ◽  
The Other ◽  
Protective Effects ◽  
Aqueous Alteration ◽  
Other Hand ◽  
Initial Stage ◽  
Good Agreement

ABSTRACTStatic aqueous alteration tests were performed with a Japanese simulated HLW glass, P0798, in the presence of bentonite in order to understand the effects of bentonite on the glass alteration kinetics and on the associated Cs release. Analogous alteration tests were performed in 0.001M NaOH solution without bentonite for comparison. The results indicated that; 1) at the initial stage of alteration up to 50 days, no remarkable difference was observed in the alteration rate between both cases “with” and “without” bentonite, 2) at the later stage beyond 50 days, however, the rate in the case “with” bentonite was larger than that in the case “without” bentonite. These results on the alteration rate were analyzed by use of a water-diffusion model. In the case “without” bentonite, a good agreement was observed between the model analysis and the experimental results at the initial stage of alteration up to 50 days, however, the model analysis deviated from the experimental results at the later stage beyond 50 days. In the case “with” bentonite, on the other hand, a good agreement was observed even at the later stage to give the value of the apparent diffusion coefficient, Di of 3.5×10−21m2/s. The comparison between both cases suggests that the alteration rate is controlled by the water diffusion in both cases “with” and “without” bentonite, however, the rate is depressed in the case “without” bentonite probably by the protective effects of the alteration layer developing at the glass surface. In the case “with” bentonite, on the other hand, the alteration layer is expected to be less protective. Cesium desorption tests performed for the altered glass and bentonite indicated that most of the cesium dissolved from the glass is retained in the secondary phase of smectite developing in the precipitated layer by sorption with ion-exchange in the case “without” bentonite. In the case “with” bentonite, however, it is likely to be sorbed at bentonite surface.

scholarly journals Studying the Effect of Paracetamol Drug on the Conductivity of 0.5M Hydrochloric Acid Solution at Different Temperatures

2013 ◽  
Vol 11 (7) ◽  
pp. 2725-2745
Author(s):  
Hadi.Z. Al-Sawaad
Keyword(s):  
Activation Energy ◽  
Hydrochloric Acid ◽  
Acid Solution ◽  
Molar Conductance ◽  
Chloride Ions ◽  
The Other ◽  
Constant Concentration ◽  
Enthalpy Of Activation ◽  
Other Hand ◽  
Different Temperatures

In this study paracetamol drug is used to reduce the conductivity of 0.5M hydrochloric acid at different concentrations for each one of them at different temperatures ranged (30-60)°C. Generally , increasing of the concentration of  the inhibitor leads to reducing in conductivity of the acid at constant temperature. On the other hand, at constant concentration of  inhibitor, the conductivity is reduced as temperature increased i.e., paracetamol can adsorbed chemically on the metal or alloy. Furthermore the kinetic study of the molar conductance process reveal that in presence of paracetamol the activation energy and enthalpy of activation are negative compared with their values in absence of paracetamol where they are negative because the reducing the conductivity in presence of paracetamol where the non spontaneous property for the conductance of acid is increased as the paracetamol concentration increased in addition to increasing the negative value of entropy in presence of paracetamol that indicate to restrict for the mobility of hydrogen and chloride ions which correspond to 90.47% as efficiency of reducing the conductance of acid by paracetamol. On the other hand thermodynamic study is achieved which explained the adsorption of paracetamol obey to Freundlisch model. 

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