Breakage Problem - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Breakage Problem

The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform

Margaritis Kostoglou – 1st expert on this subject based on the ideXlab platform

  • the equal size binary Breakage Problem evolution toward a steady shape or periodic behavior
    Journal of Colloid and Interface Science, 2006
    Co-Authors: Margaritis Kostoglou

    Abstract:

    Abstract During the last few years, the self-similar particle size distribution for a particle population undergoing Breakage in equal size fragments has been derived using approximating, numerical, and analytical means. But very recently it was shown [N.V. Mantzaris, J. Phys. A Math. Gen. 38 (2005) 5111] through transient simulation of the Breakage process that the particle size distribution in case of Breakage in two equal fragments, never attains a steady shape, i.e., a self-similar form. The new results give rise to questions about the real meaning and utility of the previously derived self-similar distributions for these systems. The scope of the present work is to answer these questions and it is attempted using only analytical (exact) means for the solution of the transient Breakage Problem. In doing so, the very interesting and rich underlying structure and properties of the solutions of the equal size Breakage Problem (seemingly, very simple) are revealed. It appears that the utility of the known self-similar distributions for this particular Problem has to be redefined but yet not entirely abandoned.

  • On the self-similar solution of fragmentation equation: Numerical evaluation with implications for the inverse Problem.
    Journal of Colloid and Interface Science, 2005
    Co-Authors: Margaritis Kostoglou, Anastasios J. Karabelas

    Abstract:

    It is well known that the fragmentation equation admits self-similar solutions for evolving particle-size distributions (PSD); i.e., if the shape of PSD is independent of time after an initial transient period. Although an analytical derivations of the self-similar PSD cases have been studied extensively, results for cases requiring numerical solutions are rare. The aim of the present work is to fill this gap for the case of homogeneous Breakage functions. The known analytical and approximate solutions for the self-similar PSD are reviewed and a general algorithm for the numerical solution is proposed. Results for a broad range of Breakage functions (kernel and rate) are presented. Further, the work is focused on the sensitivity of the relation between self-similar PSD and Breakage kernel and its influence on the inverse Breakage Problem, i.e., that of estimating the Breakage kernel from experimental self-similar PSDs. Useful suggestions are made for tackling the inverse Problem.

  • on the Breakage Problem with a homogeneous erosion type kernel
    Journal of Physics A, 2001
    Co-Authors: Margaritis Kostoglou, A J Karabelas

    Abstract:

    The Breakage equation with a homogeneous erosion type kernel is studied herein. This type of kernel renders the handling of the Breakage equation by conventional techniques very difficult, necessitating alternative Problem solving approaches. Exploiting the structure of the erosion-Breakage kernel, a new particle erosion equation is derived as the first-order term of a formal perturbation expansion with respect to kernel parameters. However, even this new equation is very difficult to treat because of the multimodality of its solution associated with the developing generations of fragments. In order to overcome this difficulty, the Problem is decomposed into a system of equations for the size distribution of the generations of fragments which admits unimodal solutions. The properties and the methods of solution (analytical, method of moments, etc) are studied extensively. Using solution techniques developed in this paper, results are reported for some simple cases, revealing a very interesting and rather unusual structure of the solutions of the erosion-Breakage equation. PACS number: 0590

P. M. Khilar – 2nd expert on this subject based on the ideXlab platform

  • VehiHealth: An Emergency Routing Protocol for Vehicular Ad Hoc Network to Support Healthcare System
    Journal of Medical Systems, 2015
    Co-Authors: S. K. Bhoi, P. M. Khilar

    Abstract:

    Survival of a patient depends on effective data communication in healthcare system. In this paper, an emergency routing protocol for Vehicular Ad hoc Network (VANET) is proposed to quickly forward the current patient status information from the ambulance to the hospital to provide pre-medical treatment. As the ambulance takes time to reach the hospital, ambulance doctor can provide sudden treatment to the patient in emergency by sending patient status information to the hospital through the vehicles using vehicular communication. Secondly, the experienced doctors respond to the information by quickly sending a treatment information to the ambulance. In this protocol, data is forwarded through that path which has less link Breakage Problem between the vehicles. This is done by calculating an intersection value I _ v a l u e for the neighboring intersections by using the current traffic information. Then the data is forwarded through that intersection which has minimum I _ v a l u e . Simulation results show VehiHealth performs better than P-GEDIR, GyTAR, A-STAR and GSR routing protocols in terms of average end-to-end delay, number of link Breakage, path length, and average response time.

A G Callagy – 3rd expert on this subject based on the ideXlab platform

  • MALFUNCTIONS OF A STEAM TURBINE MECHANICAL CONTROL SYSTEM
    Failure Analysis Case Studies II, 2020
    Co-Authors: J.h. Bulloch, A G Callagy

    Abstract:

    This paper is aimed at elucidating the cause of a series of malfunctions involving the bending or breaking of main steam turbine throttle valve spindles which occurred at service times ranging from hundreds to several thousand hours in a number of 270 MW steam raising units. It was clearly established, by two distinct approaches (one engineering, one micromechanistic) that the stresses which produced these malfunctions were bending in nature and were the result of out-of-alignment deflections. In the case of the bent spindles the stresses were very high and approached flow strength levels of around 8000 MPa while the broken spindles were the results of fatigue initiation and subsequent growth from a thread root (stress concentration) location on the spindle. Using relevant fatigue crack propagation data for the valve spindle material at 300°C it was demonstrated that fatigue failures occurred at spindle deflections of between 0.9 and 1.6 mm. Finally, it was demonstrated that the fatigue Breakage Problem could be significantly reduced, especially at the lower end of the valve spindle deflection range, by a combination of re-profiling the thread root and shot peening. © 1998 Published by Elsevier Science Ltd. All rights reserved.

  • Malfunctions of a steam turbine mechanical control system
    Engineering Failure Analysis, 1998
    Co-Authors: J.h. Bulloch, A G Callagy

    Abstract:

    This paper is aimed at elucidating the cause of a series of malfunctions involving the bending or breaking of main steam turbine throttle valve spindles which occurred at service times ranging from hundreds to several thousand hours in a number of 270 MW steam raising units. It was clearly established, by two distinct approaches (one engineering, one micromechanistic) that the stresses which produced these malfunctions were bending in nature and were the result of out-of-alignment deflections. In the case of the bent spindles the stresses were very high and approached flow strength levels of around 8000 MPa while the broken spindles were the results of fatigue initiation and subsequent growth from a thread root (stress concentration) location on the spindle. Using relevant fatigue crack propagation data for the valve spindle material at 300°C it was demonstrated that fatigue failures occurred at spindle deflections of between 0.9 and 1.6 mm. Finally, it was demonstrated that the fatigue Breakage Problem could be significantly reduced, especially at the lower end of the valve spindle deflection range, by a combination of re-profiling the thread root and shot peening.