The Thermal Explosion Confined by a Constant Temperature Boundary:I—The Induction Period Solution

1980 ◽  
Vol 39 (3) ◽  
pp. 412-430 ◽  
Author(s):  
D. R. Kassoy ◽  
Justin Poland
Keyword(s):  
Induction Period ◽  
Thermal Explosion ◽  
Constant Temperature ◽  
Period Solution

Calculation of the induction period of thermal explosion

1997 ◽  
Vol 33 (1) ◽  
pp. 1-8
Author(s):  
R. S. Burkina ◽  
I. G. Dik
Keyword(s):  
Induction Period ◽  
Thermal Explosion

Effect of reactant consumption on the induction period and critical condition for a thermal explosion

1961 ◽  
Vol 262 (1309) ◽  
pp. 192-206 ◽  
Keyword(s):  
Theoretical Model ◽  
Theoretical Analysis ◽  
Induction Period ◽  
Thermal Explosion ◽  
Numerical Solutions ◽  
Critical Value ◽  
Maximum Temperature ◽  
Analytic Expressions ◽  
Effective Transfer ◽  
Explosion Parameter

An approximate theoretical analysis is given of a thermal explosion or ignition. The treat­ment leads to analytic expressions for the effect of reactant consumption on the critical explosion parameter and the induction period for a theoretical model, where spatial varia­tion of temperature is treated by considering only the maximum temperature at the centre of the reacting material and an effective transfer coefficient between the centre and the environment. The results are found to agree satisfactorily with detailed numerical solutions by Rice, Allen & Campbell (1935) and Todes & Melentiev (1939, 1940) where these are applicable. The effect of reactant consumption on the critical value of the explosion para­meter is shown to be more than twice that calculated by Frank-Kamenetskii (1946).

THE THERMAL EXPLOSION OF LEAD AZIDE

1947 ◽  
Vol 25b (6) ◽  
pp. 548-565 ◽  
Author(s):  
A. S. Hawkes ◽  
C. A. Winkler
Keyword(s):  
Induction Period ◽  
Thermal Explosion ◽  
Crystal Size ◽  
Dibutyl Phthalate ◽  
Volume Ratio ◽  
Lead Azide ◽  
Sharp Change ◽  
Induction Periods ◽  
Self Heating

The minimum explosion temperatures for service and dextrin azides (about 315 °C. and 275 °C., respectively) are increased considerably by increase of surface: volume ratio of the container and by compressing or wetting the charge with dibutyl phthalate before explosion. When wetted, the two azides were found to be similar in respect of minimum explosion temperatures and induction periods prior to explosion. Sensitization of service azide by preheating was found to be permanent. A limit to sensitization below the minimum explosion temperature was observed, and probably exists also for sensitization above this temperature. Wetting the charge with phthalate nullifies the sensitization. Although dextrin azide alone is more thermally sensitive than service azide, mixtures of the two containing 70% or more service azide show a sharp change to service azide properties; the mixtures apparently are not exploded by the dextrin azide they contain. The value of E in the expression [Formula: see text] + constant, where t is the induction period, has been determined for both the initial and final stages of reaction preceding explosion and found to be essentially unaltered. Minimum explosion temperature of single large crystals was shown to increase with crystal size. The data are interpreted as showing that the thermal explosion of lead azide may result from self-heating, the heat of the pre-explosion reaction not being sufficiently dissipated from the material.

Fibrin Formation: The Role of the Fibrinogen-Fibrin Monomer Complex

1976 ◽  
Vol 36 (01) ◽  
pp. 037-048 ◽  
Author(s):  
Eric P. Brass ◽  
Walter B. Forman ◽  
Robert V. Edwards ◽  
Olgierd Lindan
Keyword(s):  
Particle Size ◽  
Induction Period ◽  
Fibrin Clot ◽  
Clot Formation ◽  
Appreciable Amount ◽  
Buffer System ◽  
Homeostatic Mechanism ◽  
Fibrin Formation ◽  
Fibrin Monomer

SummaryThe process of fibrin formation using highly purified fibrinogen and thrombin was studied using laser fluctuation spectroscopy, a method that rapidly determines particle size in a solution. Two periods in fibrin clot formation were noted: an induction period during which no fibrin polymerization occurred and a period of rapid increase in particle size. Direct measurement of fibrin monomer polymerization and fibrinopeptide release showed no evidence of an induction period. These observations were best explained by a kinetic model for fibrin clot formation incorporating a reversible fibrinogen-fibrin monomer complex. In this model, the complex serves as a buffer system during the earliest phase of fibrin formation. This prevents the accumulation of free polymerizable fibrin monomer until an appreciable amount of fibrinogen has reacted with thrombin, at which point the fibrin monomer level rises rapidly and polymerization proceeds. Clinically, the complex may be a homeostatic mechanism preventing pathological clotting during periods of elevated fibrinogen.

Improvement in the Fock test for determining the reactivity of dissolving pulp

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 21-26 ◽  
Author(s):  
CHAO TIAN ◽  
LINQIANG ZHENG ◽  
QINGXIAN MIAO ◽  
CHRIS NASH ◽  
CHUNYU CAO ◽  
...  
Keyword(s):  
Moisture Content ◽  
Sodium Hydroxide ◽  
Constant Temperature ◽  
Carbon Disulfide ◽  
Testing Procedure ◽  
Dissolving Pulp ◽  
Water Bath ◽  
Testing Conditions ◽  
Pulp Sample ◽  
Fock Reactivity

The Fock test is widely used for assessing the reactivity of dissolving pulp. The objective of this study was to modify the method to improve the repeatability of the test. Various parameters that affect the repeatability of the Fock test were investigated. The results showed that Fock reactivity is dependent on testing conditions affecting the xanthation between cellulose and carbon disulfide, such as the moisture content of the pulp sample, sodium hydroxide (NaOH) concentration, xanthation temperature, carbon disulfide dosage, and xanthation time. The repeatability of the test was significantly improved using the following modified testing procedure: air dried sample in the constant temperature/humidity room, xanthation temperature of 66°F (19°C) in a water bath, xanthation time of 3 h, NaOH concentration of 9% (w/w), and 1.3 mL carbon disulfide.

ACTION OF ENZYME DIGESTED PITUITARY GLANDS OF THE SKIPPER-FROG ON THE OVULATION OF THE SAME

1960 ◽  
Vol XXXIII (II) ◽  
pp. 255-260 ◽  
Author(s):  
L. S. Ramaswami ◽  
A. B. Lakshman
Keyword(s):  
Pituitary Gland ◽  
Constant Temperature ◽  
Constant Temperature Bath ◽  
Predominant Role ◽  
Lower Vertebrates ◽  
Pituitary Glands ◽  
Stimulating Factor

ABSTRACT By using enzymes, the gonadotrophic factors in the skipper-frog pituitary glands have been selectively inactivated or destroyed. By incubating a known number of pituitary gland homogenate with ptyalin in a constant temperature bath for 5–6 h the follicle-stimulating factor is inactivated; with trypsin or pepsin, the luteinizing factor is inactivated. Bioassay on gravid skipper-frogs indicate that the ptyalin digested homogenate brings about profuse spawning while the trypsin or pepsin digested homogenates do not. When a combination of ptyalin digested and trypsin digested homogenates is injected into fresh gravid skipper-frogs, poor spawning is brought about. These experiments show that the luteinizing factor alone brings about more profuse spawning than when it is combined with the follicle-stimulating factor. It is likely, therefore, that in the lower vertebrates the luteinizing factor of the pituitary gland plays a more predominant role. The exact proportions in which the different dosages for the control and test animals are administered are also tabulated.

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