scholarly journals Correction to: Dominant physical mechanisms governing the forced-convective cooling process of white mushrooms (Agaricus bisporus)

Author(s):  
Razieh Salamat ◽  
Hamid Reza Ghassemzadeh ◽  
Seyed Faramarz Ranjbar ◽  
Jochen Mellmann ◽  
Hossein Behfar

A correction to this paper has been published: https://doi.org/10.1007/s13197-021-05166-6

2020 ◽  
Vol 57 (10) ◽  
pp. 3696-3707
Author(s):  
Razieh Salamat ◽  
Hamid Reza Ghassemzadeh ◽  
Seyed Faramarz Ranjbar ◽  
Jochen Mellmann ◽  
Hossein Behfar

1998 ◽  
Vol 120 (4) ◽  
pp. 840-857 ◽  
Author(s):  
M. P. Dyko ◽  
K. Vafai

A heightened awareness of the importance of natural convective cooling as a driving factor in design and thermal management of aircraft braking systems has emerged in recent years. As a result, increased attention is being devoted to understanding the buoyancy-driven flow and heat transfer occurring within the complex air passageways formed by the wheel and brake components, including the interaction of the internal and external flow fields. Through application of contemporary computational methods in conjunction with thorough experimentation, robust numerical simulations of these three-dimensional processes have been developed and validated. This has provided insight into the fundamental physical mechanisms underlying the flow and yielded the tools necessary for efficient optimization of the cooling process to improve overall thermal performance. In the present work, a brief overview of aircraft brake thermal considerations and formulation of the convection cooling problem are provided. This is followed by a review of studies of natural convection within closed and open-ended annuli and the closely related investigation of inboard and outboard subdomains of the braking system. Relevant studies of natural convection in open rectangular cavities are also discussed. Both experimental and numerical results obtained to date are addressed, with emphasis given to the characteristics of the flow field and the effects of changes in geometric parameters on flow and heat transfer. Findings of a concurrent numerical and experimental investigation of natural convection within the wheel and brake assembly are presented. These results provide, for the first time, a description of the three-dimensional aircraft braking system cooling flow field.


1996 ◽  
Vol 118 (1) ◽  
pp. 65-72 ◽  
Author(s):  
P. K. Maciejewski

This experimental study explores the possibility that warm water may freeze in less time than cold water due to natural convection alone, i.e., in the absence of significant cooling by evaporation. This possibility is rooted in the following two hypotheses: (1) The Rayleigh number associated with a sample of warm water may exceed a critical value above which the convective motions within the water sample may become turbulent and enhance the rate of convective cooling, and (2) the inversion of the flow field that is expected to occur in the vicinity of maximum density, i.e., at 4°C, will occur at different points in the cooling process for identical samples of water at different levels of initial temperature and result in an enhanced rate of convective cooling after the flow field inversion for those cases at higher levels of initial temperature that enter the flow field inversion with higher kinetic energy. The results of this study establish that, under certain circumstances, a sample of water that is initially warm will freeze in less time than an identical sample of water that is initially cold due to natural convection alone.


Author(s):  
K. S. McCarty ◽  
R. F. Weave ◽  
L. Kemper ◽  
F. S. Vogel

During the prodromal stages of sporulation in the Basidiomycete, Agaricus bisporus, mitochondria accumulate in the basidial cells, zygotes, in the gill tissues prior to entry of these mitochondria, together with two haploid nuclei and cytoplasmic ribosomes, into the exospores. The mitochondria contain prominent loci of DNA [Fig. 1]. A modified Kleinschmidt spread technique1 has been used to evaluate the DNA strands from purified whole mitochondria released by osmotic shock, mitochondrial DNA purified on CsCl gradients [density = 1.698 gms/cc], and DNA purified on ethidium bromide CsCl gradients. The DNA appeared as linear strands up to 25 u in length and circular forms 2.2-5.2 u in circumference. In specimens prepared by osmotic shock, many strands of DNA are apparently attached to membrane fragments [Fig. 2]. When mitochondria were ruptured in hypotonic sucrose and then fixed in glutaraldehyde, the ribosomes were released for electron microscopic examination.


Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.


Author(s):  
Koenraad G F Janssens ◽  
Omer Van der Biest ◽  
Jan Vanhellemont ◽  
Herman E Maes ◽  
Robert Hull

There is a growing need for elastic strain characterization techniques with submicrometer resolution in several engineering technologies. In advanced material science and engineering the quantitative knowledge of elastic strain, e.g. at small particles or fibers in reinforced composite materials, can lead to a better understanding of the underlying physical mechanisms and thus to an optimization of material production processes. In advanced semiconductor processing and technology, the current size of micro-electronic devices requires an increasing effort in the analysis and characterization of localized strain. More than 30 years have passed since electron diffraction contrast imaging (EDCI) was used for the first time to analyse the local strain field in and around small coherent precipitates1. In later stages the same technique was used to identify straight dislocations by simulating the EDCI contrast resulting from the strain field of a dislocation and comparing it with experimental observations. Since then the technique was developed further by a small number of researchers, most of whom programmed their own dedicated algorithms to solve the problem of EDCI image simulation for the particular problem they were studying at the time.


2000 ◽  
Vol 660 ◽  
Author(s):  
Thomas M. Brown ◽  
Ian S. Millard ◽  
David J. Lacey ◽  
Jeremy H. Burroughes ◽  
Richard H. Friend ◽  
...  

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.


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