Insertion Hole Research Articles

Correction Procedures for The measurement of Permittivities with the Cavity Perturbation Method

At elevated temperatures cavity perturbation measurements with small cylindrical samples are well suited because homogeneous heating is possible and the insertion holes do not disturb the electromagnetic field around the sample. Measurements in several modes increase certainty and make cavity cooling superfluous. A careful evaluation of transmission data with a sample shape correction procedure is necessary for a good accuracy of permittivity measurement. In addition, a method is presented for the accurate determination of reference material data including the verification of reference data. To verify the theoretical considerations, a temperature controlled measurement apparatus with laser heating and temperature measurement via a pyrometer has been developed.

A Statistical Analysis of Bushing, Sleeve, and Oversize Hole Effects on the Bolted Joint Strength of Graphite/Epoxy Laminates

A test program was conducted to determine the influence of metallic hole inserts (bushings and sleeves) and over-sized fastener holes on the ultimate strength of bolted joints in IM7/8551 graphite/epoxy. Single-shear specimens were used to simulate in-service constraints; the test fixture was designed to load the test specimen at the geometric center in the thickness direction minimizing the single-shear bending problem. Protruding-head and countersunk-head fastener tests were conducted on laminate lay-ups with ply percentages of 42/50/8 and 12/80/8. The width-to-diameter ratio was held constant at 4.0, but four distinct edge distance-to-diameter ratios, 1.0, 1.5, 2.0, and 3.0, were tested for each factor. Three replicate tests were conducted for each set of parameter combinations. An analysis-of-variance of the data was conducted for each factor to determine whether or not that factor significantly influenced ultimate joint strength. Fisher's Protected Least Significant Difference procedure was then applied to the geometric and laminate lay-up parameter combinations for each factor to identify the parameter combinations where significant joint strength differences exist between the standard and nonstandard hole joints.

On a system of understanding assembly illustrations in an assembly manual

This paper presents an assembly illustration understanding system. The system is eventually expected to be applied to a robot which specializes in automated mechanical assembly. Assembly illustrations in an assembly manual usually have two features: 1) In addition to the figures corresponding to mechanical parts, several special line-drawings referred to as auxiliary lines in this paper are often employed for the visualization of the assembly relations among mechanical parts; 2) The assembly illustrations in an assembly manual are disposed sequentially so that the subgoal of an assembly illustration will definitely appear in its succeeding illustrations as an assemblage. Both features are important clues to the analysis and understanding of assembly illustrations. By extracting the auxiliary lines, the system recognizes assembly relations among mechanical parts, and the 3D shape of the mechanical parts as well. Moreover, based on the assembly relations, it conjectures the structural details of mechanical parts such as insertion holes which are usually invisible. After that, it characterizes the appearance of the completed assemblage described by the current illustration. The system finally verifies the result by matching with the figures in a succeeding illustration in which the completed assemblage is given as a subpart.

Low-noise chain and chain power transmission apparatus using the low-noise chain

A low-noise chain (1) preventing a roller (6) or a bush from contacting with a bottom portion of a sprocket (10) thus reducing impact noise. The low-noise chain includes pairs of inner link plates (2) and pairs of outer link plates (3) alternately lined up with each other, each of the link plates having two insertion holes (21, 31); connecting pins (5) inserted into the insertion holes of the link plates to couple the inner and outer link plates; and bushes or rollers (6) disposed around the connecting pin, whereby the roller (6) or bush has a substantially triangular configuration in transverse cross section and has three intermeshing surfaces (62) on its outer circumference.

Field analysis of new coaxial dielectrometer

A field analysis of a composite sample insertion hole in a coaxial re-entrant cavity is performed via a mode-matching formulation. The formulation and the numerical method are presented, and the numerical results are discussed with attention focused on the hole effects on the dielectric loaded cavity. Based on the analysis, and the structure that allows for the sample insertion holes, a dielectrometer featuring both ease of sample insertion and accuracy in dielectric determinations is obtained. It is demonstrated that solid, liquid, or powdered samples can be readily accommodated and measured, and the dielectric data obtained via two theoretically calculated calibration curves are in good agreement with published data. >

Improvements in the analysis of a TH0mp cavity for precise complex permittivity measurements

AbstractAn analysis of the relationship between complex permittivity and complex resonance frequency is proposed for a cylindrical cavity oscillating in a TM0mp mode. Effects of wall conductivity, coupling loops, and holes for the insertion of dielectric samples are fully taken into account. With dielectric samples of small radii, insertion holes produce the most important corrections. Their effect is modelled through a finite difference solution of the field equations in the neighbourhood of the holes. A computer program is described for the analysis, the use of which is illustrated with results of measurements.

Mechanical type ultrasonic scanner

First Page

Shift of the complex resonance frequency of a dielectric-loaded cavity produced by small sample insertion holes

The presence of small sample insertion holes in a cylindrical cavity produces a shift in the complex resonance frequency of the cavity. A mathematical model is proposed to compute the shift when the cavity oscillates in an axially symmetric TM/sub 0mp/ mode The treatment applies to samples with arbitrary complex permittivity. The model is compared to other treatments and checked against measured results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Heat resultant of uniaxial stress field in rock

Laboratory experiments on cylindrical samples of sandstone and bituminous coal were undertaken dealing with precise measurements of temperature change during uniaxial compression of test pieces until failure occured. Temperature gradients are quoted as a function of stress, and the internal stress field is defined. Effect of the rate of stress and heat dissipation in time under steady load were determined experimentally. Thermal stress concentration factor at the gage insert holes was calculated to facilitate conversion of apparent thermal gradients into real internal heat values. The internal energy balance based on measurements of modulus of elasticity, strain hysteresis, and thermal properties of rocks, and calculated heat flow, is submitted. A rheologic interpretation of the measured effects based on the results of previous rheology-of-rock investigations, and Burgers' body strain energy calculation, is quoted. Satisfactory agreement of theoretical and experimental results was obtained.

Biology ofEvechinus chloroticus(Echinoidea: Echinometridae) from different localities

Summary During late December 1967 and January 1968, 310 Evechinus chloroticus (Val.) were tagged with anchor tags at four marked subtidal sites in Third Bay, Kaikoura. Tag recoveries after 3, 6 and 9 months were approximately 57%, 26% and 17%. Tagged urchins were recovered only at the marked sites and only small numbers (6% at 3 months and 10% at 6 months) had moved between sites; these urchins had moved ‘from the nearest neighbouring sites, the maximum distance between these being 4.8 m. Gonad condition and amount of food in the gut were compared for 50 tagged and 30 untagged urchins 9 months after tagging. Of tagged urchins, only five had gonads of normal size and appearance and only 18 could be sexed. Mean gonad indices of tagged and untagged urchins were 0.43 and 1.12. The amount of food in the gut of tagged specimens was generally less than that of untagged specimens. Tag insertion holes were not sealed by regenerated test and no significant changes in test diameter had occurred in tagged specimens a...

Errors in Dielectric Measurements Due to a Sample Insertion Hole in a Cavity

The measurement of complex permittivities of isotropic media at microwave frequencies is performed with high precision by means of cylindrical cavity resonators. However, a hole in the cavity wall, for inserting the sample causes a frequency pulling of the resonator, which in turn introduces an error in the measured dielectric constant. These effects are measured, and with perturbation theory as a guide, correction factors are developed.