DAMAGE HEALING IN SINGLE COMPONENT IRREVERSIBLE REACTION PROCESSES

1995 ◽  
Vol 09 (09) ◽  
pp. 565-571
Author(s):  
EZEQUIEL V. ALBANO

The spreading of a globally distributed damage, created in the stationary regime, is studied in single component irreversible reaction processes on one-dimensional lattices. Each model exhibits an irreversible phase transition between a stationary reactive state and an inactive (absorbing) state. It is found that the processes are immune in the sense that even 100% of initial damage is healed within a finite healing period (T H ). Within the reactive regime, T H diverges when approaching criticality and the corresponding exponent is independent of the process, i.e. it seems to be universal for one-component systems.

1995 ◽  
Vol 48 (10) ◽  
pp. 650-658 ◽  
Author(s):  
J. R. Philip

We review the phenomenological approach, on the macroscopic or Darcy scale, to flow and volume change in clays and other swelling media. The formulation represents the generalization to media subject to volume change of the well-established phenomenological approach to flow in non-swelling media primarily established in the context of soil physics. The one-dimensional generalization to swelling media is straightforward, and may be usefully applied to practical one-dimensional systems, including three-component systems with solid particles, water, and air. On the other hand, the further generalizations to two- and three-dimensional systems have not yet been developed fully convincingly. Difficult questions include the mode of stress transmission and the tensorial stress-strain relations in multidimensional and multi-component systems. One means of gaining insight into these questions for media of high colloid content (such as clays) is through relevant solutions of the Poisson-Boltzmann equation governing electrical double-layer interactions in dense arrays of colloidal particles. These solutions give pertinent information on both the macroscopic and the microscopic scales. We present a progress report on work along these lines.


2003 ◽  
Vol 31 (3) ◽  
pp. 258-268 ◽  
Author(s):  
Singiresu S. Rao ◽  
David E. Foster

Due to the demands on the engineering profession, all products and systems are expected to satisfy certain availability requirements. The availability is a measure of the readiness of a product or system for use at any specified time. In this work, the availability of single-component systems is addressed. Monte Carlo simulation is used to estimate the availability of the system, assuming that the failure and repair times follow exponential, normal (Gaussian), and uniform probability distributions. The results are compared. Although the availability functions look very different, the steady-state availability is the same for all. Also, the availability of a component whose hazard function follows the bathtub curve is estimated, and it is found that the exponential distribution is not a good approximation, especially at the earliest stages of operation.


2005 ◽  
Vol 68 (2) ◽  
pp. 375-383 ◽  
Author(s):  
YANN GUIAVARC'H ◽  
FRANÇOIS ZUBER ◽  
ANN VAN LOEY ◽  
MARC HENDRICKX

Two original, highly dehydrated, small single-component enzymatic time-temperature integrator (TTI) systems, TTIL and TTIS, were prepared. Their z-values were 13.9 and 16.4°C, respectively, and they were based on Bacillus licheniformis αamylase and Bacillus subtilis α-amylase, respectively. The isothermal calibration of these two TTIs revealed that (i) they can be used in the temperature range of 100 to 140°C, (ii) results can be read within 5 min, and (iii) they can be used individually for the measurements of process values 13.9°CF121.1°C and 16.4°CF121.1°C up to 98 min and 85 min, respectively. Because these two TTIs have different z-values above 10°C, they could be used in combination with the multicomponent TTI concept to estimate process values 10°CF121.1°C inside particles of a solid or liquid food submitted to rotary processing. Raviolis in tomato sauce sterilized in an industrial-scale reel and spiral continuous retort were examined in this study. Two methods, based on the combination of a one-dimensional explicit finite difference heat-transfer model with the experimental responses of the TTIs, were used to take into account the possible deviations in evaluation of 10°CF121.1°C values. A process value 10°CF121.1°C of 23.6 min with a standard deviation of 1.5 min was determined inside raviolis using the multicomponent TTI approach, and a process value 10°CF121.1°C of 33.6 min with a standard deviation of 1.5 min inside the sauce was calculated from the temperature recording data.


2019 ◽  
Vol 275 ◽  
pp. 849-858 ◽  
Author(s):  
G. Shanker ◽  
A. Bindushree ◽  
K. Chaithra ◽  
P. Pratap ◽  
Ravindra Kumar Gupta ◽  
...  

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