Defects examination

In a number of diseases, the patient develops multiple coagulation defects. Examination of the blood demonstrates slow formation of a loose and friable clot in vitro, even when thrombin is present. This results from increased fibrinolytic activity in plasma. These clinical entities will be further reviewed after the mechanism of plasminogen activation to plasmin is discussed. 

Defects in condoms were examined, characterised and compared with defects introduced using various techniques. Eighty-five percent of the condom defects examined were classified as either a hole (void in material) or a slit (puncture). Laser drilling and puncturing with a 160 micrometre diameter acupuncture needle artificially introduced similar types of defects. Microscopic examination of the created defects, before and after FDA water leak testing. 

To examine the accumulation effect activity ( A ZT) in the adhesive joints of the carbon plastic, the artificial defects were made. The samples were loaded up to the stress of 0,6"Zf. The test has showed (table 2) that in the weak samples the acoustic emission, at the repeated loading, will start at the point, which is smaller, than initial loading. While, the weaker sample, the bigger value of the "S. ... 

Representative set of weldments was examined site welds (with pearlitic type weld metal) and two types of site weld repair zones with different welding technologies using Cr-Ni filler metals and Ni-based alloy. Results of AUGUR 4.2 inspection were compared with manual ultrasonic inspection ones in terms of defect detection, characterization, positioning and sizing in order to estimate correlation between these data. 

Information supplied by flaw visualization systems has decisive influence on fracture assessment of the defect. Results of expert ultrasonic examination show that in order to take advantage of AUGUR4.2 potentialities in full measure advanced methods of defect assessment should be applied using computer modelling, in-site data of material mechanical properties and load monitoring [4]. 

But, with the use of digitization, 2D quantitative measurements are allowed for industrial radiography. These can be done by powerful tools, like estimation of defect extension, automatic segmentation, recognition of individual defects and image analysis (figure 7). For validation, results can be compared with destractive examination of metallic objects. 

For detection of defect dimensions defectometers were used made of examined sample material allowing to reveal defects of 0.25-1% x-rayed steel layer thickness in range of 100-500mm thickness at 11 MeV. 

A particular attention must be given to the examination of spectra, because they can be an error source. The magnetic spectrum presence is very important, because it conditions the testing sanction. Generally we proceed to an identification of the real defect nature which has lead to the formation of the spectrum... 

Speckle shearing interferometry, or shearography, is a full field optical inspection teclmique that may be used for the nondestructive detection of surface and, sometimes, subsurface defects. Whilst being more sensitive in the detection of surface defects, it may also be considered for pipe inspection and the monitoring of internal conoslon. In contrast, laser ultrasound and other forms of ultrasound, are point by point measurement techniques, so that scanning facilities and significant data processing is required before information on local defects is extracted from any examination of extensive areas [1 - 3]. 

Manual ultrasonic testing offers the advantages of low equipment cost combined with the flexibility of the human operator to provide good access and complex scanning capability. However, a total reliance on the capabilities of the ultrasonic technician to visualise the physical situation leads to a number of drawbacks, including lack of accuracy and consistency of defect size and location measurements, lack of verification that the required scan coverage has been fully achieved, and lack of consistency in flaw classification. A further disadvantage is that the ultrasonic data is not permanently recorded there is therefore no opportunity for the data to be re-examined at a later date if required. 

Often repair of the found defects is extremely undesirable. Therefore, for discontinuities which are potentially hazardous, it is very important to have a onfirmation of their stability. In this case monitoring of potentially hazardous discontinuities is well supported by automated UT systems and based on the comparative analysis results, the actual data from examination of a section of the welded joint of a (hydrogen) separator are given in Figures 5,6. 

This study detects the defect of the void and the exfoliation in the solid phase diffusion bonding interface of ductile cast iron and stainless steel with a nickel insert metal using ultrrasonic testing method, and examine the influence of mutual interference of the reflectional wave both the defect and the interface. 

First of all, the influence of the thickness of the insert metal ( on the echo height F/B when not defective is examined. 

F/B due to the changing defect area s ratio as follows is examined, when f/ X is a constant value. 

After the performance demonstration a number of damaged rotor blades were scanned followed by a number of destructive verifications of the results achieved by ultrasonic scanning. Based on this examination it was concluded that the wind turbine rotor blade scanner is capable of detecting defects such as delaminations, inclusions, missing adhesion, lack of adhesive, porosities and variations in thickness. 

Edcfy-cufrent NDT inspections using spatial data (sampled scans) ha >e many benefits. They separate the two conflicting aspects of an inspection scanning and signal interpretation. An instrument/display (client/server) based NDT inspection based on sampled scan data aides in the training and certification of inspectors. It can be used over the Internet or in-house Intranet networks to train or examine inspectors at multiple or remote sites. This saves travel time and resources as defects, instrumentation and teaching can all be consolidated Samples can be maintained and distributed from a central certification body providing more control andflexibility. 

Sampled scan data would be a benefit when it comes to certification of new inspectors or re-certification of existing staff. A large database of scans could be compiled and used randomly at test centres, which would help to avoid the samples becoming too familiar. Examinations could also be more easily tailored to the probes, types of materials and types of defects the inspector is likely to see. 

Dislocation theory as a portion of the subject of solid-state physics is somewhat beyond the scope of this book, but it is desirable to examine the subject briefly in terms of its implications in surface chemistry. Perhaps the most elementary type of defect is that of an extra or interstitial atom—Frenkel defect [110]—or a missing atom or vacancy—Schottky defect [111]. Such point defects play an important role in the treatment of diffusion and electrical conductivities in solids and the solubility of a salt in the host lattice of another or different valence type [112]. Point defects have a thermodynamic basis for their existence in terms of the energy and entropy of their formation, the situation is similar to the formation of isolated holes and erratic atoms on a surface. Dislocations, on the other hand, may be viewed as an organized concentration of point defects they are lattice defects and play an important role in the mechanism of the plastic deformation of solids. Lattice defects or dislocations are not thermodynamic in the sense of the point defects their formation is intimately connected with the mechanism of nucleation and crystal growth (see Section IX-4), and they constitute an important source of surface imperfection. 

To examine the soUd as it approaches equUibrium (atom energies of 0.025 eV) requires molecular dynamic simulations. Molecular dynamic (MD) simulations foUow the spatial and temporal evolution of atoms in a cascade as the atoms regain thermal equiUbrium in about 10 ps. By use of MD, one can foUow the physical and chemical effects that induence the final cascade state. Molecular dynamics have been used to study a variety of cascade phenomena. These include defect evolution, recombination dynamics, Hquid-like core effects, and final defect states. MD programs have also been used to model sputtering processes. 

MgCl2-Supported Catalysts. Examination of polymerizations with TiCl catalysts has estabUshed that only a small percentage of titanium located on lateral faces, edges, and along crystal defects is active (52) (see Titanium and titanium alloys). This led to the recognition that much of the catalyst mass acted only as a support, promoting considerable activity aimed at finding a support for active titanium that would not be detrimental to polymer properties. 

Mercury thermometers are subject to separation of the mercury column or to inclusion of bubbles of the fiU gas. These may result from shipping and handling and cause a scale offset which can usually be seen upon visual examination, and they are always recogni2ed by a 0°C verification check. Manufacturers will suggest means by which these temporary defects may be cured. 

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