Improving the Efficiency of Ultrasonic Testing Based on Additional Information on Defect Scattering Indicatrices

2019 ◽  
Vol 55 (5) ◽  
pp. 353-362
Author(s):  
R. Kh. Rafikov
Keyword(s):  
Ultrasonic Testing ◽  
Additional Information ◽  
Scattering Indicatrices

APPLICATION OF INCLINED LONGITUDINAL ULTRASONIC WAVES TO IMPROVE THE EFFICIENCY OF RAIL FLAW DETECTION

2021 ◽  
pp. 4-13
Author(s):  
A. A. Markov ◽  
V. V. Mosyagin ◽  
S. L. Molotkov ◽  
G. A. Ivanov
Keyword(s):  
Mathematical Modeling ◽  
Ultrasonic Testing ◽  
Flaw Detection ◽  
Flaw Detector ◽  
Ultrasonic Waves ◽  
Shadow Method ◽  
Additional Information ◽  
Location Depth ◽  
Definition Of ◽  
Longitudinal Ultrasonic Waves

The article is devoted to the question of rail ultrasonic testing confidence. At present there is a range of flaw orientation angles in within which the testing is absent and, therefore such flaws can be lost. To except this drawback the current sound testing scheme in flaw detector railcars is to be supplemented with inclined probes exciting longitudinal wave. Experimental checks using echomethod showed the good results on an October railway section with flaw models and on a loaded Zabaycalskaya railway section. The next step was idea of mirror-shadow method using as well as echomethod by turning of probes towards each other. Envelope analysis of bottom signals allows receiving additional information about flaws: location depth of its center and form. But using of pair of probes was not enough for unambiguous definition of other geometric flaws characteristics. That is why the bottom signal envelope of straight probe was to be analyzed additionally. A mobile (as well removable) searching system of rail checking means has such probe as a rule. In the process of writing the article previously obtained formulas to calculate depth, inclination angle and plane size of revealed flaw were modified. Values changing during testing process are absent now. Algorithm of flaws identification on the basis of bottom signals envelope is given. The approach is confirmed by mathematical modeling in CIVA-UT.

IDENTIFICATION AND RELIABILITY OF CONTROL IN ULTRASONIC FLAW DETECTION AND DEFECTOMETRY

2020 ◽  
pp. 4-17
Author(s):  
V. G. Badalyan
Keyword(s):  
Ultrasonic Testing ◽  
Flaw Detection ◽  
Roc Curves ◽  
Probability Of Detection ◽  
Ultrasonic Control ◽  
Ultrasonic Flaw Detection ◽  
Control Techniques ◽  
Additional Information ◽  
Ultrasonic Flaw ◽  
Non Destructive

The effectiveness of methods and means of ultrasonic non-destructive control (ultrasonic control) is evaluated by the probability of detecting defects and the reliability of the results of the control. In this work, we reserch the behavior of PoD(a) – the defect detection function, which describes the dependence of the probability of detection of defects on their height, and estimates the reliability of control by means of ROC analysis of the control data. An analysis of the PoD curves obtained by ultrasonic testing with ultrasonic flaw detection and ultrasonic flaw detection instruments demonstrates significantly greater reliability of the use of defectometry techniques and devices. ROC curves constructed using ultrasonic defectometry data make it possible to evaluate the reliability of control of defects of various heights. Analysis of ROC curves provides additional information for optimizing ultrasonic control techniques. The studies were carried out on the data array of ultrasonic testing of welded joints with real cracks.

Production of New and Revised A.A.V.S.O. Charts

1979 ◽  
Vol 46 ◽  
pp. 368
Author(s):  
Clinton B. Ford
Keyword(s):  
Variable Star ◽  
Standard Form ◽  
Original Data ◽  
University Of Pennsylvania ◽  
Standard Format ◽  
Additional Information ◽  
The Gift ◽  
The University

A “new charts program” for the Americal Association of Variable Star Observers was instigated in 1966 via the gift to the Association of the complete variable star observing records, charts, photographs, etc. of the late Prof. Charles P. Olivier of the University of Pennsylvania (USA). Adequate material covering about 60 variables, not previously charted by the AAVSO, was included in this original data, and was suitably charted in reproducible standard format.Since 1966, much additional information has been assembled from other sources, three Catalogs have been issued which list the new or revised charts produced, and which specify how copies of same may be obtained. The latest such Catalog is dated June 1978, and lists 670 different charts covering a total of 611 variables none of which was charted in reproducible standard form previous to 1966.

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Edge Penetration Effects in the Low-Loss Electron Image in the SEM

1988 ◽  
Vol 46 ◽  
pp. 202-203
Author(s):  
Oliver C. Wells
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Beam Energy ◽  
Secondary Electron ◽  
Sharp Edge ◽  
Beam Diameter ◽  
Low Loss ◽  
Additional Information ◽  
Electron Image ◽  
Scanning Electron

The low-loss electron (LLE) image in the scanning electron microscope (SEM) is useful for the study of uncoated photoresist and some other poorly conducting specimens because it is less sensitive to specimen charging than is the secondary electron (SE) image. A second advantage can arise from a significant reduction in the width of the “penetration fringe” close to a sharp edge. Although both of these problems can also be solved by operating with a beam energy of about 1 keV, the LLE image has the advantage that it permits the use of a higher beam energy and therefore (for a given SEM) a smaller beam diameter. It is an additional attraction of the LLE image that it can be obtained simultaneously with the SE image, and this gives additional information in many cases. This paper shows the reduction in penetration effects given by the use of the LLE image.

Questions and Answers

2000 ◽  
Vol 5 (2) ◽  
pp. 3-3
Author(s):  
Christopher R. Brigham ◽  
James B. Talmage
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Spinal Nerve ◽  
Sensory Loss ◽  
Residual Symptoms ◽  
Additional Information ◽  
Questions And Answers ◽  
Motor Nerves ◽  
Symptoms And Signs ◽  
Limited Motion

Abstract Lesions of the peripheral nervous system (PNS), whether due to injury or illness, commonly result in residual symptoms and signs and, hence, permanent impairment. The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) describes procedures for rating upper extremity neural deficits in Chapter 3, The Musculoskeletal System, section 3.1k; Chapter 4, The Nervous System, section 4.4 provides additional information and an example. The AMA Guides also divides PNS deficits into sensory and motor and includes pain within the former. The impairment estimates take into account typical manifestations such as limited motion, atrophy, and reflex, trophic, and vasomotor deficits. Lesions of the peripheral nervous system may result in diminished sensation (anesthesia or hypesthesia), abnormal sensation (dysesthesia or paresthesia), or increased sensation (hyperesthesia). Lesions of motor nerves can result in weakness or paralysis of the muscles innervated. Spinal nerve deficits are identified by sensory loss or pain in the dermatome or weakness in the myotome supplied. The steps in estimating brachial plexus impairment are similar to those for spinal and peripheral nerves. Evaluators should take care not to rate the same impairment twice, eg, rating weakness resulting from a peripheral nerve injury and the joss of joint motion due to that weakness.

Markers of arterial stiffness in peripheral arterial disease

VASA ◽  
2015 ◽  
Vol 44 (5) ◽  
pp. 341-348 ◽  
Author(s):  
Marc Husmann ◽  
Vincenzo Jacomella ◽  
Christoph Thalhammer ◽  
Beatrice R. Amann-Vesti
Keyword(s):  
Arterial Stiffness ◽  
Peripheral Arterial Disease ◽  
Pulse Wave ◽  
Augmentation Index ◽  
Arterial Disease ◽  
Care Physician ◽  
Additional Information ◽  
Non Invasive ◽  
Assessment Techniques ◽  
Peripheral Arterial

Abstract. Increased arterial stiffness results from reduced elasticity of the arterial wall and is an independent predictor for cardiovascular risk. The gold standard for assessment of arterial stiffness is the carotid-femoral pulse wave velocity. Other parameters such as central aortic pulse pressure and aortic augmentation index are indirect, surrogate markers of arterial stiffness, but provide additional information on the characteristics of wave reflection. Peripheral arterial disease (PAD) is characterised by its association with systolic hypertension, increased arterial stiffness, disturbed wave reflexion and prognosis depending on ankle-brachial pressure index. This review summarises the physiology of pulse wave propagation and reflection and its changes due to aging and atherosclerosis. We discuss different non-invasive assessment techniques and highlight the importance of the understanding of arterial pulse wave analysis for each vascular specialist and primary care physician alike in the context of PAD.

Heart Rate Variability, Homeostasis, and Brain Function

2012 ◽  
Vol 26 (4) ◽  
pp. 178-203 ◽  
Author(s):  
Francesco Riganello ◽  
Sergio Garbarino ◽  
Walter G. Sannita
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Vegetative State ◽  
Communication Disorders ◽  
Affective States ◽  
Experimental Conditions ◽  
Cardiovascular Research ◽  
Sensory Stimuli ◽  
Additional Information ◽  
Brain Injured

Measures of heart rate variability (HRV) are major indices of the sympathovagal balance in cardiovascular research. These measures are thought to reflect complex patterns of brain activation as well and HRV is now emerging as a descriptor thought to provide information on the nervous system organization of homeostatic responses in accordance with the situational requirements. Current models of integration equate HRV to the affective states as parallel outputs of the central autonomic network, with HRV reflecting its organization of affective, physiological, “cognitive,” and behavioral elements into a homeostatic response. Clinical application is in the study of patients with psychiatric disorders, traumatic brain injury, impaired emotion-specific processing, personality, and communication disorders. HRV responses to highly emotional sensory inputs have been identified in subjects in vegetative state and in healthy or brain injured subjects processing complex sensory stimuli. In this respect, HRV measurements can provide additional information on the brain functional setup in the severely brain damaged and would provide researchers with a suitable approach in the absence of conscious behavior or whenever complex experimental conditions and data collection are impracticable, as it is the case, for example, in intensive care units.

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