Interactions Between Electromagnetic and Thermal Fields in Microwave Heating of Hardened Type I-Cement Paste Using a Rectangular Waveguide (Influence of Frequency and Sample Size)

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
P. Rattanadecho ◽  
N. Suwannapum ◽  
W. Cha-um
Keyword(s):  
Microwave Heating ◽  
Cement Paste ◽  
Power Distribution ◽  
Rectangular Waveguide ◽  
Three Dimensional ◽  
Heating Time ◽  
Detailed Knowledge ◽  
Type I ◽  
Two Dimensional ◽  
Materials Research

Microwave heating-drying of hardened Type I-cement paste using a rectangular waveguide is a relatively new area of cement-based materials research. In order to gain insight into the phenomena that occur within the waveguide together with the temperature distribution in the heated cement paste samples, a detailed knowledge of absorbed power distribution is necessary. In the present paper, a three-dimensional finite difference time domain scheme is used to determine electromagnetic fields (TE10-mode) and microwave power absorbed by solving transient Maxwell’s equations. Two-dimensional heat transport within the cement paste located in rectangular waveguide is used to evaluate the variations of temperature with heating time at different frequencies and sample sizes. A two-dimensional heating model is then validated against experimental results and subsequently used as a tool for efficient computational prototyping.

Stability Analysis Of Cracks Propagating In Three Dimensional Solids

1995 ◽  
Vol 409 ◽  
Author(s):  
H. Larralde ◽  
A. A. Al-Falou ◽  
R. C. Ball
Keyword(s):  
Perturbation Theory ◽  
Stability Analysis ◽  
Fracture Surface ◽  
Three Dimensional ◽  
Type I ◽  
Two Dimensional ◽  
Singular Terms ◽  
First Order ◽  
Left Behind ◽  
First Order Perturbation

AbstractWe present a theory for the morphology of the fracture surface left behind by slowly propagating cracks in linear, isotropic and homogeneous three dimensional solids. Our results are based on first order perturbation theory of the equations of elasticity for cracks whose shape is slightly perturbed from planar. For cracks propagating under pure type I loading we find that all perturbation modes are linearly stable, from which we can predict the roughness of the fracture surface induced by fluctuations in the material. We compare our results with the classical results for cracks propagating in two dimensional systems, and discuss the effects in the three dimensional analysis which result from taking into account contributions from non-singular terms of the stress field, as well as the effects arising from finite speeds of crack propagation.

scholarly journals Crystal structure of a three-dimensional neodymium(III) coordination polymer, [Nd2(H2O)6(glutarato)(SO4)2] n

2022 ◽  
Vol 78 (2) ◽  
Author(s):  
Saranphong Yimklan ◽  
Yothin Chimupala ◽  
Sutsiri Wongngam ◽  
Nippich Kaeosamut
Keyword(s):  
Crystal Structure ◽  
Coordination Polymer ◽  
Hydrogen Bonds ◽  
Microwave Heating ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Coordination Network ◽  
Dinuclear Cluster ◽  
Trigonal Prismatic

A three-dimensional coordination polymer, poly[hexaaqua(μ4-glutarato)bis(μ3-sulfato)dineodymium(III)], [Nd2(H2O)6(glutarato)(SO4)2] n (glutarato2– = C5H6O4 2–), 1, consisting of cationic {Nd2(H2O)6(SO4)2} n 2n+ layers linked by bridging glutarate ligands, was synthesized by the microwave-heating technique within few minutes. The crystal structure of 1 consists of two crystallographically independent TPRS-{NdIIIO9} (TPRS is tricapped trigonal–prismatic geometry) units that form an edge-sharing dinuclear cluster interconnected to neighbouring dimers by the μ3-SO4 2– anions, yielding a cationic two-dimensional {Nd2(H2O)6(SO4)2} n 2n+ sheet. Adjacent cationic layers are then linked via the μ4-glutarato2– ligands into a three-dimensional coordination network. Strong O—H...O hydrogen bonds are the predominant interaction in the crystal structure.

The Use Of Backscattered Electron Microscopy And Image Analysis To Study The Porosity Of Cement Paste

1988 ◽  
Vol 137 ◽  
Author(s):  
Karen L. Scrivener
Keyword(s):  
Electron Microscopy ◽  
Image Analysis ◽  
Cement Paste ◽  
Serial Section ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Image Analyser ◽  
Backscattered Electron ◽  
Solid Phases ◽  
Serial Section Reconstruction

AbstractIn backscattered electron images of polished sections of cement paste pores can be identified down to a size of about 0.05 microns. Moreover, the contrast between pores and the solid phases is sufficient to allow the pores to be distinguished and quantified by an image analyser. There is a good correlation between measures of porosity obtained by this technique and those obtained by methanol absorbtion methods despite the lower limit to resolution.The bse method can also be used to study the distribution of the porosity in space. However, as only two dimensional sections can be examined, there are difficulties in determining the connectivity by this method. The possibility of using serial section reconstruction is examined and discussed.Despite the difficulty in relating two dimensional characterisation to three dimensional properties, several techniques have been used with some success for sandstones. Results from these techniques for cement paste are presented and discussed.

scholarly journals The effect of poloidal magnetic field on type I planetary migration

2007 ◽  
Vol 3 (S249) ◽  
pp. 401-406
Author(s):  
Takayuki Muto ◽  
Masahiro N. Machida ◽  
Shu-ichiro Inutsuka
Keyword(s):  
Magnetic Field ◽  
Numerical Calculation ◽  
Strong Field ◽  
Three Dimensional ◽  
Rotational Instability ◽  
Linear Perturbation ◽  
Type I ◽  
Two Dimensional ◽  
Poloidal Magnetic Field ◽  
Planetary Migration

AbstractWe study the effect of poloidal magnetic field on type I planetary migration by linear perturbation analysis with the shearing-sheet approximation and the analytic results are compared with numerical calculation. We investigate the cases where magneto-rotational instability (MRI) does not occur: either the disk is two-dimensional, or a very strong field is exerted. We derive formulae for torque exerted on the planet for both cases. We find that two-dimensional torque is suppressed when plasma beta is less than 1 and three-dimensional modes dominate, in contrast to unmagnetized case.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

A linearity test for thick specimens imaged by HVEM over a 180° angular range

1991 ◽  
Vol 49 ◽  
pp. 552-553
Author(s):  
Yu Liu
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Angular Range ◽  
Two Dimensional ◽  
Back Projection ◽  
Line Integral ◽  
Exponential Law ◽  
Transmission Electron ◽  
Absorption Law ◽  
Linearity Test

The image obtained in a transmission electron microscope is the two-dimensional projection of a three-dimensional (3D) object. The 3D reconstruction of the object can be calculated from a series of projections by back-projection, but this algorithm assumes that the image is linearly related to a line integral of the object function. However, there are two kinds of contrast in electron microscopy, scattering and phase contrast, of which only the latter is linear with the optical density (OD) in the micrograph. Therefore the OD can be used as a measure of the projection only for thin specimens where phase contrast dominates the image. For thick specimens, where scattering contrast predominates, an exponential absorption law holds, and a logarithm of OD must be used. However, for large thicknesses, the simple exponential law might break down due to multiple and inelastic scattering.

An Image Reconstruction System Applied to High Voltage Microscopy

1975 ◽  
Vol 33 ◽  
pp. 292-293
Author(s):  
D. E. Johnson
Keyword(s):  
High Voltage ◽  
Prior Information ◽  
Block Diagram ◽  
Three Dimensional ◽  
Real Space ◽  
Two Dimensional ◽  
Efficient Manner ◽  
Fourier Methods ◽  
Tilt Series ◽  
Methods Of Reconstruction

Increased specimen penetration; the principle advantage of high voltage microscopy, is accompanied by an increased need to utilize information on three dimensional specimen structure available in the form of two dimensional projections (i.e. micrographs). We are engaged in a program to develop methods which allow the maximum use of information contained in a through tilt series of micrographs to determine three dimensional speciman structure.In general, we are dealing with structures lacking in symmetry and with projections available from only a limited span of angles (±60°). For these reasons, we must make maximum use of any prior information available about the specimen. To do this in the most efficient manner, we have concentrated on iterative, real space methods rather than Fourier methods of reconstruction. The particular iterative algorithm we have developed is given in detail in ref. 3. A block diagram of the complete reconstruction system is shown in fig. 1.

Computer Assisted Image Reconstruction of Oligomer Structure

1976 ◽  
Vol 34 ◽  
pp. 472-473
Author(s):  
A.M. Jones ◽  
A. Max Fiskin
Keyword(s):  
Three Dimensional ◽  
Depth Of Field ◽  
Computer Assisted ◽  
Projection Data ◽  
Two Dimensional ◽  
Single Particles ◽  
Dimensional Reconstruction ◽  
Computer Assisted Image ◽  
The Fourier Transform ◽  
Space Approach

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.

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