A New Approach For Dielectric Measurements At High Temperatures

1996 ◽  
Vol 430 ◽  
Author(s):  
C. Groffils ◽  
P. J. Luypaert ◽  
Y. Zhou ◽  
O. Van der Biest
Keyword(s):  
Perturbation Method ◽  
High Temperatures ◽  
Dielectric Constants ◽  
Dielectric Measurements ◽  
New Approach ◽  
Extraction Algorithm ◽  
Frequency Scan ◽  
Different Temperatures ◽  
Cold Cavity ◽  
Full Network

AbstractMost of the algorithms for cavity dielectric measurements use a full network frequency scan for the perturbation method. At high temperature the measurement points in one frequency scan will have different temperatures due to the fast cooling of the sample inside the cold cavity. This paper presents a new approach for the perturbation method to measure dielectric constants at high temperatures with a two port, two piston cylindrical cavity and external furnace. Special features of this cavity are the possibility to work with different modes and different relative positions of the coupling aperture.The dielectric properties are extracted from the full sets of S-parameters for two successive frequency points corresponding to approximately the same temperatures. An extraction algorithm is developed and programmed.

scholarly journals New Approach to the Planetary Theory

1979 ◽  
Vol 81 ◽  
pp. 69-72 ◽  
Author(s):  
Manabu Yuasa ◽  
Gen'ichiro Hori
Keyword(s):  
Perturbation Method ◽  
Canonical Form ◽  
Equations Of Motion ◽  
Disturbing Function ◽  
Averaging Principle ◽  
The Sun ◽  
Planetary Theory ◽  
New Approach ◽  
Canonical Perturbation ◽  
Relative Coordinates

A new approach to the planetary theory is examined under the following procedure: 1) we use a canonical perturbation method based on the averaging principle; 2) we adopt Charlier's canonical relative coordinates fixed to the Sun, and the equations of motion of planets can be written in the canonical form; 3) we adopt some devices concerning the development of the disturbing function. Our development can be applied formally in the case of nearly intersecting orbits as the Neptune-Pluto system. Procedure 1) has been adopted by Message (1976).

Influence of Heat on Seed Germination of Cistus Laurifolius and Cistus Ladanifer

1992 ◽  
Vol 2 (1) ◽  
pp. 15 ◽  
Author(s):  
L Valbuena ◽  
R Tarrega ◽  
E Luis
Keyword(s):  
Seed Germination ◽  
High Temperatures ◽  
Exposure Time ◽  
Germination Rate ◽  
Heat Exposure ◽  
Cistus Ladanifer ◽  
Different Temperatures ◽  
Petri Dishes ◽  
Germinated Seeds

The influence of high temperatures on germination of Cistus laurifolius and Cistus ladanifer seeds was analyzed. Seeds were subjected to different temperatures for different times, afterwards they were sowed in plastic petri dishes and monitored for germinated seeds over two months.The germination rate observed in Cistus ldanifer was greater than in Cistus laurifolius. In both species, heat increased germination percentages. For Cistus laurifolius higher temperatures or longer exposure times were needed. Germination percentages of Cistus ladanifer were lower when heat exposure time was 15 minutes.It must be emphasized that germination occurred when seeds were not treated, while seeds exposed to 150�C for 5 minutes or more did not germinate.

Linear and non-linear analysis on two-dimensional steel frame under different temperatures

2019 ◽  
Vol 10 (1) ◽  
pp. 48-55
Author(s):  
Parthasarathi N. ◽  
Satyanarayanan K.S. ◽  
Prakash M. ◽  
Thamilarasu V.
Keyword(s):  
High Temperatures ◽  
Progressive Collapse ◽  
Transient State ◽  
Steel Frame ◽  
Frame Structure ◽  
Two Dimensional ◽  
Content Type ◽  
Frame Building ◽  
Different Temperatures ◽  
Steel Frame Structure

Purpose Progressive collapse because of high temperatures arising from an explosion, vehicle impact or fire is an important issue for structural failure in high-rise buildings. Design/methodology/approach The present study, using ABAQUS software for the analysis, investigated the progressive collapse of a two-dimensional, three-bay, four-storey steel frame structure from high-temperature stresses. Findings After structure reaches the temperature results like displacement, stress axial load and shear force are discussed. Research limitations/implications Different temperatures were applied to the columns at different heights of a structure framed with various materials. Progressive collapse load combinations were also applied as per general service administration guidelines. Originality/value This study covered both steady-state and transient-state conditions of a multistorey-frame building subjected to a rise in temperature in the corner columns and intermediate columns. The columns in the framed structure were subjected to high temperatures at different heights, and the resulting displacements, stresses and axial loads were obtained, analysed and discussed.

Evaluation of Secondary Flow between Rotating Concentric Spheres Using a Perturbation Method

2021 ◽  
Vol 412 ◽  
pp. 49-72
Author(s):  
R. Leticia Corral Bustamante ◽  
Antonino H. Pérez ◽  
Alfredo L. Márquez
Keyword(s):  
Perturbation Method ◽  
Secondary Flow ◽  
Analytical Method ◽  
Analytic Solution ◽  
Previous Analysis ◽  
Secondary Flows ◽  
Newtonian Flow ◽  
New Approach ◽  
Concentric Spheres ◽  
Method Show

A new approach to evaluate the Newtonian flow between concentric rotating spheres is introduced in this paper. A general analytic solution to the problem is deduced using a perturbation method that takes into account the primary and secondary flows produced between the spheres, as well as an alternative analytical method. In order to exemplify the results of the previous analysis, six particular cases were studied. The results of the perturbation method show that under certain circumstances the secondary flow is no negligible, as is usually considered, but it is comparable to the value of the primary one. While the analytical method allows us to simulate the flow with results very similar to those of other authors.

scholarly journals Effects of High Temperatures on the Physical and Mechanical Properties of Carbonated Ordinary Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Qifang Xie ◽  
Lipeng Zhang ◽  
Shenghua Yin ◽  
Baozhuang Zhang ◽  
Yaopeng Wu
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Elastic Modulus ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Time Service ◽  
Different Temperatures ◽  
Cooling Methods

Fires are always known for seriously deteriorating concrete in structures, especially for those with certain carbonation due to long-time service. In this paper, 75 prism specimens were prepared and divided into four groups (three carbonated groups and one uncarbonated group). Specimens were tested under different temperatures (20, 300, 400, 500, 600, and 700°C), exposure times (3, 4, and 6 hours), and cooling methods (water and natural cooling). Surface characteristics, weight loss rate, and residual mechanical properties (strength, initial elastic modulus, peak, and ultimate compressive strains) of carbonated concrete specimens after elevated temperatures were investigated and compared with that of the uncarbonated ones. Results show that the weight loss rates of the carbonated concrete specimens are slightly lower than that of the uncarbonated ones and that the cracks are increased with raising of temperatures. Surface colors of carbonated concrete are significantly changed, but they are not sensitive to cooling methods. Surface cracks can be evidently observed on carbonated specimens when temperature reaches 400°C. Residual compressive strength and initial elastic modulus of carbonated concrete after natural cooling are generally larger than those cooled by water. The peak and ultimate compressive strains of both carbonated and uncarbonated concrete specimens increase after heating, but the values of the latter are greater than that of the former. Finally, the constitutive equation to predict the compressive behaviors of carbonated concrete after high temperatures was established and validated by tests.

scholarly journals A New Approach to Approximate Solutions for Nonlinear Differential Equation

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Safia Meftah
Keyword(s):  
Differential Equation ◽  
Differential Equations ◽  
Small Parameter ◽  
Perturbation Method ◽  
Periodic Solutions ◽  
Asymptotic Expansions ◽  
Nonlinear Differential Equations ◽  
Approximate Solutions ◽  
Approximation Methods ◽  
New Approach

The question discussed in this study concerns one of the most helpful approximation methods, namely, the expansion of a solution of a differential equation in a series in powers of a small parameter. We used the Lindstedt-Poincaré perturbation method to construct a solution closer to uniformly valid asymptotic expansions for periodic solutions of second-order nonlinear differential equations.

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