GaAlAs


Single reactions. In a single reaction such as Eq. (2.2) which produces a byproduct, there can be no influence on the relative amount of product and byproduct formed. Thus, with single reactions such as Eqs. (2.1) to (2.3), the goal is to minimize the reactor capital cost (which usually means minimizing reactor volume) for a given reactor conversion. Increasing the reactor conversion increases size and hence cost of the reactor but, as we shall see later.  [c.25]

Multiple reactions. The arguments presented for minimizing reactor volume for single reactions can be used for the primary reaction when dealing with multiple reactions. However, the goal at this stage of the design, when dealing with multiple reactions, is to maximize selectivity rather than to minimize volume for a given conversion.  [c.41]

If the goal is to maximize profit, NPV is used. If the supply of capital is restricted (which is usual), DCFRR is used to decide which projects will use the capital most efficiently.  [c.424]

Disulphur monoxide, S2O, SSO. Unstable, glow discharge on SOj.  [c.379]

Cementation describes the glueing together of components. The glue often consists of material like quartz or various carbonate minerals. They may be introduced to the system by either percolating pore water and/or by precipitation of minerals as a result of changes in pressure and temperature. Compaction may for instance lead to quartz dissolution at the contact point of individual grains where pressure is highest. In areas of slightly lower pressure, e.g. space between the pores, precipitation of quartz may result (Fig. 5.11 ).  [c.86]

The main goal during the pneumatic test (loading and pressure holds) is to have a pre-warning system against any catastrophic failure during the pneumatic loading (gas pressure test).(4)  [c.32]

The main goal achieved by the proposed pattern recognition analysis for the signature recognition of AE signals, is the reliable identification of distinct damage stages which in turn enables the definition of evaluation eriteria based on the presence or absence of each class of signals. The results prove the great help the method provides to the AE analyst in order to discover the statistical nature of AE signals, as well as to make useful correlation with the source of emission.  [c.44]

II- 3,1 0,1 Of the border carbon plastic -glue  [c.87]

II- 9,9 >1 0,4 Of the border carbon plastic -glue  [c.87]

In the experiments, the probabilities were estimated from the processed signal by means of a histogram. It is well known that the entropy is large for nearly uniform distributions and small for distributions with few peaks. Thus it is an interesting candidate as a performance measure when the goal is to process a signal to become more easily interpreted.  [c.91]

The goal of this presentation is to propose a more or less general approach based on Gibbs statistics to the basic problem of introducing a priori knowledge into the reconstruction algorithms. The application to three-level structure reconstruction, which is quite actual for NDT, will be chosen as object to illustrate the proposed approach. It will be shown that Bayesian Reconstruction technique using Gibbs priors gives a straight forward way to implement fast algorithms for image restoration from extremely limited number of projections and views of multi-level structures.  [c.114]

This paper deals with a specific Non-Destructive Evaluation technique, the characterization of anomalies in conductive media by eddy current tomography. The goal is thus to build up an image of a spatial map (the object function which is representative of the flaw) from measurements of a scattered field. A coil is used to induce eddy currents in the inspected flawed region. Eddy currents interact with the flaw and we take samples of the normal component of the scattered magnetic field near the air-conductor interface. The inverse scattering problem then consists of reconstructing the object function from the measurements (observed data). This tomographic approach in non-destructive evaluation brings up many questions and difficulties.  [c.326]

The demonstrator whose goal is to establish feasibility studies and to size specific industrial tools is now operating in FRAMATOME Technical Center.  [c.397]

The standard will make a substantial contribution toward the achievement of the goal "Radioscopy - as much as possible radiography - as much as necessary .  [c.441]

We have demonstrated that the IP-ND can be effectively used in direct NR for NDT. Since the neutron flux and other characteristics of the present NR facility of the Ljubljana TRIGA Mark reactor, as L/D ratio of about 60-80 and gamma-ray dose rate of I 5 10 mSv/s, are just in the range of performances of modern neutron generators we can conclude that the IP-ND are prospective neutron image detectors in the NR with mobile neutron sources. A NR image of part of an helicopter standing strut is presented in Fig. 2 Details in the distribution of the glue between the metal plates can be clearly resolved as well as few corroded A1 structural parts (upper Al skin)  [c.509]

The actual goal of the development was not to replace glass tubes in their main markets, but to open new markets for X-ray tubes in general.  [c.532]

The primary goal of fixer desilvering is to remove silver from the fixer solution. This desilvering occurs at the cathode, and in good desilvering units, it is performed with an efficiency of well above 90%.  [c.606]

Accurate modelling of the field radiated by ultrasonic transducers is an essential step forward considering the final goal of the complete simulation of pulse echo experiments.  [c.735]

The goal of URT is to obtain reflectivity images from back-scattered measurements. This consists in a Fourier synthesis problem, and the first task is to correctly cover the frequency space of the "object" r. Let for simplicity the dimension of the physical space be 2.  [c.745]

The diagnostic goal Methods and means  [c.912]

Over the past years FORCE Institute has modified the P-scan system for several applications on a wide range of composite structures. By means of flexible scanner units combined with the P-scan processor, F ORCE Institute has achieved promising results with on-site automated ultrasonic inspection of fibre-reinforced polymers, such as aircraft structures, GFRP-pipes, vessels, tanks and ship structures. These results have initiated a close co-operation between FORCE Institute, RISO and two major producers of wind turbine rotor blades with the main goal to improve non-destructive inspection techniques for inspection of modern wind turbine rotor blades. Today modern rotor blades are mainly produced as a large GFRP-structure. As a consequence of application of larger and larger rotor blades, safety considerations mandate new requirements for inspection techniques that can be used to gain information of the quality of these blades.  [c.980]

Historically the legal framework in the North Sea has been prescriptive in nature, that is specifying through statute precisely what should be undertaken and when. Following Piper Alpha, a comprehensive review of all aspects of health and safety in the North Sea was undertaken by Lord Cullen and his team. The resulting Cullen Report (ref 1) included consideration of the way in which other industries in the UK were regulated and in particular the goal setting philosophy advocated in the Robens Report (ref 2) which was published in 1974. In this Robens recognised that the best interests of health and safety require the commitment and involvement of two key parties - those who create the risks and those who are affected by them. The role of the government in this approach should be to set the minimum objectives and enforce them, not dictate the detail and prescribe the means to meet the set objectives. Robens stated in his report  [c.1010]

The usual practical situation is that in which two solids are bonded by means of some kind of glue or cement. A relatively complex joint is illustrated in Fig. XII-14. The strength of a joint may be measured in various ways. A common standard method is the peel test in which the normal force to separate the joint  [c.455]

Multiple reactions in parallel producing byproducts. Raw materials costs usually will dominate the economics of the process. Because of this, when dealing with multiple reactions, whether parallel, series, or mixed, the goal is usually to minimize byproduct formation (maximize selectivity) for a given reactor conversion. Choice of reactor conditions should exploit diflTerences between the kinetics and equilibrium effects in the primary and secondary reactions to favor the formation of the desired product rather than the byproduct, i.e., improve selectivity. Making an initial guess for conversion is more difficult than with single reactions, since the factors that affect conversion also can have a significant effect on selectivity.  [c.26]

The sponsoring editor for this book was Gail F. Nalven, the editing supervisor was Peggy Lamb, and the production supervisor was Donald F. Schmidt. This book was set in Century Schoolbook by The Universities Press (Belfast) Ltd.  [c.464]

C7H6O5. Colourless crystals with one molecule of water, m.p. 253" C, sparingly soluble in water and alcohol. It occurs free in woody tissue, in gall-nuts and in tea, and is a constituent of the tannins, from which it can be obtained by fermentation or by acid hydrolysis. It gives a blue-black colour with Fe and is used in the manufacture 6f inks. On heating it gives pyrogallol.  [c.185]

Note, however, the particular cases of sulfur in crude oil from Rozel Point (Utah, USA) 13.95% in crudes from Etzel (Germany) 9.6% or crude from Gela  [c.320]

Table 2 shows total results of the registered parameters. A big dispersion of the shift resistance value of the adhesive joints was recorded. This can be explained by presence of defects in the main material or in the gluey process. For example, according to the data of fraction-graphical analysis, the destruction of the weak adhesive joints has a mixed character that is the destruction is taking place partly in the glue layer (thick glue layer), and, partly -in the adhesive joint (places without glue, with weak adhesion and etc.). The solid adhesive joints have the destruction, as a rule, on the carbon plastic.  [c.85]

The main goal of ultrasonic grain noise suppression in material flaw detection is to improve the perceptual possibilities of the operator to observe defect echoes. The suppression is defined as perceptually ideal when a received signal (or image) which contains echoes buried in noise is filtered to yield nonzero values only at the positions of the defect echoes.  [c.89]

This article presents methods of synthesis and objective control of special flat optical elements (computer-synthesized holograms) as elements of protection. Due to the limited number of pages, we cannot go into great detail to explain the technology of how computer-synthesized holograms are created. The goal of this publication is to discuss following subjects  [c.264]

It cannot be expected that IP s with their different characteristics in comparison to the film can be applied in the same way. Special filters must be configured to optimize the exposure arrangement. The comparison to the film should be performed generally under optimized conditions for both systems. The image quality achieved by the NDT-film system classes is the basis for the comparison and evaluation of the CR by IP s. The exposure process and the handling of the IP s is optimized with the goal to achieve the same or better image quality than film systems. Similar factors influence the image quality due to optical scattering, limitations of data processing and monitor properties. For the performed measurements systems from AGFA and Fuji-Film were tested.  [c.467]

The threshold density of electrons was taken equal to 10 cm A visible image in GDC is formed by visible radiation of excited atoms of an inert gas or by a visible glow of a luminescent layer. This glowing is induced by UV radiation of gas discharges. The yield of visible radiation of discharges in GDC Xe is of two orders lower, compared with UV radiation and image brightness does not exceed 10 cd/m (for frequency 25 Hz), which is not enough for proper visualization of images and difficult for recording. The source of UV radiation are excimeric molecules of an inert gas, resulting from triple collissions with participation of resonant-excited atoms. The excimer radiation propagates out of a gas discharge volume to a luminescent layer by a radiative way, increasing unsharpness of images on this layer. High intensity of UV radiation is sufficient for nonlinear luminescence of layers and decreases unsharpness of images - by 1,5 times on the layers (5-10) mcm thick, that operate for luminous transmission, that compensates image blurring, related to radiative propagation of UV radiation. The image of good quality can be obtained when recording a charge pattern with a GDC anode (with spatial resolution 3-4 lines/mm).  [c.539]

The Government is making strenuous effort to develop local industries to create employment and reduce dependence on imports in many sectors for ultimate goal of achieving socio economic development of the people. Simultaneously, it is high time now to see that the use of the local NDT expertise is ensured so that the national economic development is supported by promoting quality productivity of industrial enterprises and their competitiveness. Accordingly much progress is to be achieved for the institutional infrastractural developments for application of NDT in Bangladesh in which international community of scientists, engineers researchers including similar institutions also too have great roles to play as her partner in progress.  [c.921]

The competent authority for the elaboration of standards in the European Union is the CEN (Comite Europeen de Normalisation - European Committee for Standardization), which consists of several Technical Committees (TC). Among these ones, CEN/TCI38 ("nondestructive testing") is in charge of the standards concerning qualification and certification of personnel (now published as EN473) and of the "general" standards for each of the main NDT methods [2], To achieve the latter goal, it contains 8 working groups (called "disciplinary working groups" in this paper), each one devoted to a particular method radiography, ultrasonics, eddy currents, penetrant testing, magnetic particle inspection, leak testing, acoustic emission and visual inspection.  [c.923]

Together with LM Glasfiber, FORCE Institute has now developed two new scariners one for inspection of filament winded beams, and one for inspection of bonded joints on rotor blades. The main goal of the project was to develop automated ultrasonic inspection equipment which can be applied on damaged rotor blades, new designs and for production inspection. The two scanners, both controlled by the P-scan system, have been tested with promising results on rotor blades with both artificially and naturally introduced defects such as delaminations, inclusions, missing adhesion, lack of adhesive, porosities and variations in thickness. The newly developed scanners make it possible to scan large bonded areas in a fast and systematic way. The scanners are controlled by the P-scan system, which automatically gives access to a wide range of inspection parameters including a unique visualisation of inspection results.  [c.983]

The detailed examination of the behavior of light passing through or reflected by an interface can, in principle, allow the determination of the monolayer thickness, its index of refiraction and absorption coefficient as a function of wavelength. The subjects of ellipsometry, spectroscopy, and x-ray reflection deal with this goal we sketch these techniques here.  [c.126]

Two models for adhesive joint failure are the following. One is essentially a classic, mechanical picture, relating stored elastic energy and the work of crack propagation, known as the Griffith-Irwin criterion (see Ref. 110). Bik-erman [111], however, has argued that the actual situation is usually one of a weak boundary layer. This was thought to be a thin layer (but of greater than molecular dimensions) of altered material whose mechanical strength was less than that of either bulk phase. While oxides, contamination, and so on, could constitute a weak boundary layer, it was also possible that this layer could be structurally altered but pure material. Interestingly, Schonhom and Ryan [112] found that proper cleaning of a plastic greatly improved the ability to bond it to metal substrates. Good ([113], but see Ref. 110 also) has argued that the molecular interface may often be the weakest layer and that adhesive failure is at the true interface. A rather different idea, especially applicable to the peel test procedure, is due to Deijaguin (see Ref. 114). The peeling of a joint can produce static charging (sometimes visible as a glow or flashing of light), and much of the work may be due to the electrical work of, in effect, separating the plates of a charged condenser.  [c.456]


See pages that mention the term GaAlAs : [c.65]    [c.90]    [c.103]    [c.188]    [c.191]    [c.196]    [c.196]    [c.252]    [c.361]    [c.384]    [c.26]    [c.981]    [c.451]    [c.451]   
Encyclopedia of materials characterization (1992) -- [ c.393 ]