Separation at the Interface of a Circular Inclusion and the Surrounding Medium Under an Incident Compressive Wave

1970 ◽  
Vol 37 (2) ◽  
pp. 298-304 ◽  
Author(s):  
J. D. Achenbach ◽  
J. H. Hemann ◽  
F. Ziegler
Keyword(s):  
Focal Point ◽  
Characteristic Impedance ◽  
Surrounding Medium ◽  
Circular Inclusion ◽  
Front Face ◽  
Analytical Treatment ◽  
Compressive Wave ◽  
Tensile Wave ◽  
Shadow Side ◽  
Dynamic Loading Conditions

Separation at the interface of a circular inclusion embedded in a matrix of lower characteristic impedance and subjected to incident compressive waves is investigated, both experimentally and analytically. In the experiment, the compressive waves were generated by small explosive charges. For small charges, separation was not observed. As the explosive charge was increased, separation was observed at the “shadow side” of the inclusion. For still higher charges, separation was observed at the front face as well as at the shadow side of the inclusion. The qualitative analytical treatment is based on the methods of propagating stress discontinuities. It is shown that a compressive stress wave is converted into a tensile wave after a refraction and a reflection inside the inclusion. The reflected discontinuity of the tensile stress at the wave front is magnified upon passage through a focal point before reaching the shadow side of the inclusion. A divergence factor in conjunction with the closer proximity of the caustic to the back face reduces the level of tensile stresses reaching the front face. Separation is thus less likely to occur at the front face, which was verified experimentally. The results of this paper apply to the behavior of fiber-reinforced composites under dynamic loading conditions.

Culture Features in Car’s Headlights Form Design

2013 ◽  
Vol 706-708 ◽  
pp. 2079-2082
Author(s):  
Hui Ling Zhou ◽  
Kai Ling Li
Keyword(s):  
Focal Point ◽  
Front Face ◽  
Cultural Perspective ◽  
Development Trends ◽  
Genetic Characteristics ◽  
Organization Structures ◽  
Internal Relations ◽  
Form Design

Headlights are the focal point of the car-front-face. The genetic characteristics and development trends of Camry headlights were summarized by comparing their organization structures and making analogy with eyes. From cultural perspective, the internal relations between headlights characteristics and the esthetical psychology featured "quietude、shadows、harmony“ were suggested.

scholarly journals An investigation into the development of a portable, ultrasonic, density measuring instrument

1987 ◽  
Author(s):  
◽  
Nigel Douglas Hulse
Keyword(s):  
Physical Properties ◽  
Ultrasonic Transducer ◽  
Characteristic Impedance ◽  
Surrounding Medium ◽  
Density Measurement ◽  
Mining Industry ◽  
Organic Liquids ◽  
Probe Design ◽  
Measuring Instrument ◽  
Mineral Slurry

In the gold mining industry, one of the significant physical properties of the mineral slurry is its density and it is important to be able to measure this parameter in most processes. There are many techniques for determining the density of fluids, but because of the hostile, abrasive nature of mineral slurry, very few of these are suitable, This dissertation describes the deveiopment, construction and testing of a portable, ultrasonic, density measuring instrument. The instrument uses an ultrasonic transducer as the primary measuring element, and system operation is based on the fact that the driving impedance of the transducer varies with changes in the physical properties, and hence the characteristic impedance, of the surrounding medium into which the ultrasonic energy is being transferred. The technique may a-Lao be used to measure the relative concentrations of two liquids in a mixture or emulsion, provided that the characteristic impedances of the liquids are sufficiently dissimilar. The electronic circuitry is fairly straightforward, consisting essentially of an oscillator, driving circuit for the transducer and a voltage monitor to provide a d.c. voltage proportional to the impedance of the transducer, and hence to the density of the surrounding medium. Most of the research has been concentrated on the probe design, as the type of transducer, the type and thickness of facing material and the method of construction all contribute to the sensitivity of the instrument. A design of probe assembly has been developed that may be used for both slurry density measurement and the measurement of the ratio of aqueous to organic liquids in emulsion.

scholarly journals Mathematical theory and analytical solutions for the wave catching-up phenomena in a nonlinearly elastic composite bar

2012 ◽  
Vol 468 (2148) ◽  
pp. 3882-3901 ◽  
Author(s):  
Shou-Jun Huang ◽  
Hui-Hui Dai ◽  
Zhen Chen ◽  
De-Xing Kong
Keyword(s):  
Mathematical Theory ◽  
Multiple Reflections ◽  
Compressive Wave ◽  
Catching Up ◽  
Tensile Wave ◽  
Wave Patterns ◽  
Quantitative Results ◽  
Material Composite ◽  
Nonlinearly Elastic ◽  
General Mathematical Theory

Cracking induced by tensile wave at the free surface of an impacted target is an important issue in impact-resistant design. Here, we explore the use of material nonlinearity to undermine the strength of the tensile wave. More specifically, we consider waves in a two-material composite bar subjected to impact loading at one end. Multiple reflections cause a tensile wave being transmitted into the second material. The attention is on analytically and numerically studying the phenomenon that the tensile wave catches the first transmitted compressive wave. It turns out that, depending on the interval of the initial impact, catching-up phenomena can happen in two wave patterns. A general mathematical theory is provided to show the existence of these patterns together with some qualitative information. To gain more insights into such phenomena, asymptotic solutions are also constructed, which provide both qualitative and quantitative results on the requirement of the constitutive relation, the time and place at which the catching takes place, and how the initial impact, material and geometric parameters influence the solutions. Numerical simulations are also performed, confirming the validity of the analytical results. The analysis and results presented here could be useful for designing a composite structure that has a good impact-protection performance.

Integrating perspectives: How the development of second-personal competence lays the foundation for a second-personal morality

2020 ◽  
Vol 43 ◽  
Author(s):  
John Corbit ◽  
Chris Moore
Keyword(s):  
Empirical Evidence ◽  
Developmental Process ◽  
Focal Point ◽  
Personal Information ◽  
Personal Competence ◽  
Triadic Interactions ◽  
Personal Morality ◽  
Integrative Process

Abstract The integration of first-, second-, and third-personal information within joint intentional collaboration provides the foundation for broad-based second-personal morality. We offer two additions to this framework: a description of the developmental process through which second-personal competence emerges from early triadic interactions, and empirical evidence that collaboration with a concrete goal may provide an essential focal point for this integrative process.

CBED Shadow Images and Cs:Aberration Measurement

1982 ◽  
Vol 40 ◽  
pp. 696-697
Author(s):  
R. W. Carpenter ◽  
I.Y.T. Chan ◽  
J. M. Cowley
Keyword(s):  
Focal Point ◽  
Spherical Aberration ◽  
Optic Axis ◽  
Wide Angle ◽  
Caustic Surface ◽  
Convergent Beam

Wide-angle convergent beam shadow images(CBSI) exhibit several characteristic distortions resulting from spherical aberration. The most prominent is a circle of infinite magnification resulting from rays having equal values of a forming a cross-over on the optic axis at some distance before reaching the paraxial focal point. This distortion is called the tangential circle of infinite magnification; it can be used to align and stigmate a STEM and to determine Cs for the probe forming lens. A second distortion, the radial circle of infinite magnification, results from a cross-over on the lens caustic surface of rays with differing values of ∝a, also before the paraxial focal point of the lens.

The Fine Structure of Rat Granulosa Cell Cultures Correlated with Progestin Secretion

1973 ◽  
Vol 31 ◽  
pp. 552-553
Author(s):  
T. M. Crisp ◽  
F.R. Denys
Keyword(s):  
Fine Structure ◽  
Granulosa Cell ◽  
Cell Cultures ◽  
Single Injection ◽  
Surrounding Medium ◽  
Petri Dish ◽  
Female Rats ◽  
Vaginal Smear ◽  
Immature Female ◽  
Serum Gonadotropin

The purpose of this paper is to present observations on the fine structure of rat granulosa cell cultures grown in the presence of an adenohypophyseal explant and to correlate the morphology of these cells with progestin secretion. Twenty-six day old immature female rats were given a single injection of 5 IU pregnant mares serum gonadotropin (PMS) in order to obtain ovaries with large vesicular follicles. At 66 hrs. post-PMS administration (estrus indicated by vaginal smear cytology), the ovaries were removed and placed in a petri dish containing medium 199 and 100 U penicillin/streptomycin (P/S)/ml. Under a 20X magnification dissecting microscope, some 5-8 vesicular follicles/ovary were punctured and the granulosa cells were expressed into the surrounding medium. The cells were transferred to centrifuge tubes and spun down at 1000 rpm for 5 mins.

Electrostatic optics and aberration correction in the 1940s and today

1992 ◽  
Vol 50 (1) ◽  
pp. 6-7
Author(s):  
Gertrude F. Rempfer
Keyword(s):  
Electron Microscope ◽  
Focal Point ◽  
Focal Length ◽  
High Vacuum ◽  
Electron Optics ◽  
Applied Physics ◽  
Electrostatic Lenses ◽  
Commercial Instrument ◽  
The University ◽  
Theory And Experiment

I became involved in electron optics in early 1945, when my husband Robert and I were hired by the Farrand Optical Company. My husband had a mathematics Ph.D.; my degree was in physics. My main responsibilities were connected with the development of an electrostatic electron microscope. Fortunately, my thesis research on thermionic and field emission, in the late 1930s under the direction of Professor Joseph E. Henderson at the University of Washington, provided a foundation for dealing with electron beams, high vacuum, and high voltage.At the Farrand Company my co-workers and I used an electron-optical bench to carry out an extensive series of tests on three-electrode electrostatic lenses, as a function of geometrical and voltage parameters. Our studies enabled us to select optimum designs for the lenses in the electron microscope. We early on discovered that, in general, electron lenses are not “thin” lenses, and that aberrations of focal point and aberrations of focal length are not the same. I found electron optics to be an intriguing blend of theory and experiment. A laboratory version of the electron microscope was built and tested, and a report was given at the December 1947 EMSA meeting. The micrograph in fig. 1 is one of several which were presented at the meeting. This micrograph also appeared on the cover of the January 1949 issue of Journal of Applied Physics. These were exciting times in electron microscopy; it seemed that almost everything that happened was new. Our opportunities to publish were limited to patents because Mr. Farrand envisaged a commercial instrument. Regrettably, a commercial version of our laboratory microscope was not produced.

A confocal laser scanning microscope for fluorescence and reflection at video rates

1989 ◽  
Vol 47 ◽  
pp. 134-135
Author(s):  
P.M. Houpt ◽  
A. Draaijer
Keyword(s):  
Light Source ◽  
Laser Scanning ◽  
Focal Point ◽  
Confocal Laser Scanning Microscope ◽  
Confocal Laser ◽  
Point Light Source ◽  
Volume Of Interest ◽  
Ion Laser ◽  
Point Light ◽  
Point Detector

In confocal microscopy, the object is scanned by the coinciding focal points (confocal) of a point light source and a point detector both focused on a certain plane in the object. Only light coming from the focal point is detected and, even more important, out-of-focus light is rejected.This makes it possible to slice up optically the ‘volume of interest’ in the object by moving it axially while scanning the focused point light source (X-Y) laterally. The successive confocal sections can be stored in a computer and used to reconstruct the object in a 3D image display.The instrument described is able to scan the object laterally with an Ar ion laser (488 nm) at video rates. The image of one confocal section of an object can be displayed within 40 milliseconds (1000 х 1000 pixels). The time to record the total information within the ‘volume of interest’ normally depends on the number of slices needed to cover it, but rarely exceeds a few seconds.

Atomic Imaging of Crystals using Large-Angle Electron Scattering in STEM

1990 ◽  
Vol 48 (1) ◽  
pp. 74-75
Author(s):  
D.E. Jesson ◽  
S. J. Pennycook
Keyword(s):  
Wave Function ◽  
Electron Scattering ◽  
Numerical Solutions ◽  
Large Angle ◽  
Real Space ◽  
High Angle ◽  
Analytical Treatment ◽  
Order Zero ◽  
Experimental Conditions ◽  
Ewald Sphere

It is well known that conventional atomic resolution electron microscopy is a coherent imaging process best interpreted in reciprocal space using contrast transfer function theory. This is because the equivalent real space interpretation involving a convolution between the exit face wave function and the instrumental response is difficult to visualize. Furthermore, the crystal wave function is not simply related to the projected crystal potential, except under a very restrictive set of experimental conditions, making image simulation an essential part of image interpretation. In this paper we present a different conceptual approach to the atomic imaging of crystals based on incoherent imaging theory. Using a real-space analysis of electron scattering to a high-angle annular detector, it is shown how the STEM imaging process can be partitioned into components parallel and perpendicular to the relevant low index zone-axis.It has become customary to describe STEM imaging using the analytical treatment developed by Cowley. However, the convenient assumption of a phase object (which neglects the curvature of the Ewald sphere) fails rapidly for large scattering angles, even in very thin crystals. Thus, to avoid unpredictive numerical solutions, it would seem more appropriate to apply pseudo-kinematic theory to the treatment of the weak high angle signal. Diffraction to medium order zero-layer reflections is most important compared with thermal diffuse scattering in very thin crystals (<5nm). The electron wave function ψ(R,z) at a depth z and transverse coordinate R due to a phase aberrated surface probe function P(R-RO) located at RO is then well described by the channeling approximation;

A preliminary study on the potential of front face fluorescence spectroscopy for the discrimination of Moroccan virgin olive oils and the prediction of their quality

2021 ◽  
Author(s):  
Hicham Zaroual ◽  
El Mestafa El Hadrami ◽  
Romdhane Karoui
Keyword(s):  
Fluorescence Spectroscopy ◽  
Olive Oil ◽  
Virgin Olive Oil ◽  
Front Face ◽  
Virgin Olive Oils ◽  
Olive Oils ◽  
Preliminary Study

This study examines the feasibility of using front face fluorescence spectroscopy (FFFS) to authenticate 41 virgin olive oil (VOO) samples collected from 5 regions in Morocco during 2 consecutive crop seasons.

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