There is now a simple explicit expression for the vapor rate in a single column in terms of the feed to the column. In order to use this expression to screen column sequences, the vapor rate in each column must be calculated according to Eq. (5.8), assuming a sharp separation in each column, and the individual vapor rates summed.  [c.137]

The ultimate reference in guiding process changes to reduce utility costs and utility waste is the plus/minus principle. However, process changes so identified prompt changes in the capital/energy tradeoff and utility selection. Using the total cost targeting techniques described in Chaps. 6 and 7, it is possible to effectively screen a wide range of options using relatively simple computation. In the next three chapters we shall focus in detail on heat integration of reactors and heat-driven separators.  [c.323]

C (decomp.) It is made by the oxidation of toluene-o-sulphonamide with alkaline permanganate. Saccharin has about 550 times the sweetening power of sucrose, and is used extensively as a sweetening agent, usually in the form of the sodium salt. The use of saccharin is restricted in the U.S.  [c.350]

Ozone, known for its beneficial role as a protective screen against ultraviolet radiation in the stratosphere, is a major pollutant at low altitudes (from 0 to 2000 m) affecting plants, animals and human beings. Ozone can be formed by a succession of photochemical reactions that preferentially involve hydrocarbons and nitrogen oxides emitted by the different combustion systems such as engines and furnaces.  [c.261]

In the internal gravel pack shown, carefully sorted sand grains, called gravel, are placed between a wire wrapped screen and the perforations with the objective of stopping  [c.228]

The upi-SO screen display ( Figure 7 ) shows the A-scan signal (top) and the resulting B-scan image (bottom) for the tandem arrangement of Figure 6. The flaw reflection is seen on the left.  [c.167]

Figure 7 upi-SO screen display.  [c.167]

There are several important partial results. (1) Definition of quality of the CT-data in relation to the imaging task, including a model of the X-ray paths and how it is used to predict the optimal performance. (2) A model and method to determine how the information of the imaged object transfer from the detector entrance screen through the detector chain to CT  [c.208]

The theoretical model of the CT-data collection process is shown schematically in figure 5. The X-ray spectrum generated in the X-ray source is shown to the left. Spectra for the actual X-ray source were measured with high accuracy with a Compton spectrometer [4, 5]. The spectrum chosen is pre-shaped with filters and then divided into three paths. Sj penetrates the object beside the defect, S2 penetrates both object and defect, and So passes beside the object. The X-ray spectrum will be filtered differently along each path, that is, both by number of photons and change of energy distribution. The expectation value for the energy imparted to the detector screen at each path, Ei(e) where i=0-2, is a product of the expectation value for the number of photons in each spectra, Ei(N), and the expectation value of the single event distribution, Ei(e ). The single event distributions for paths S0.2 in the middle in the figure represent the detector screen simulated with Monte Carlo technique [6].  [c.210]

Information of the energy imparted to the entrance screen is then transferred through a number of conversions in the detector chain, which introduce pixel-to-pixel correlation, before it is stored as digital data. This correlation has to be considered to be able to predict absolute signal and noise levels in the stored, data the noise would otherwise be overestimated.  [c.211]

Finally, the multiple visualization used by the P-Scan allows to have available A, B, C and D-Scans to the screen representation.  [c.226]

The sizing defect method consists in selecting a defect in C-Scan image and framing it by an adjustable window in length and in width. Then, results are printed on the screen of the computer.  [c.227]

Conventional eddy current probes induce eddy currents in the material parallel to the surface. Corrosion forces these currents to seek different paths, resulting in a change in their magnetic fields and hence a change in the impedance of an absolute sensing or receiving coil. This impedance change, shown on the screen of an eddy current instrument, is primarily an indication of the average volumetric metal loss.  [c.283]

A typical RTR system consists of a image intensifier, CCD camera, image processor and high resolution TV monitor in addition to radiographic source. Image intensifiers used in X-radiography employ Csl as the input detector. With the increased use of neutrons as radiation source, real time neutron radiography is also being practised widely. Image intensifiers used in neutron radiography employ gadolinium as the input screen. Typical resolutions attainable with present day X-ray and neutron image intensifiers is of the order 45 Ip/cm in the nornial mode. It is well known that rare earth screens such as gadolinium oxysulphide are sensitive to photons as well. While such screens have been used in fluoroscopy, no systematic study has been made to evaluate their potential usage for real time applications using X-rays. One possible reason for this could be due to their non-linear response over the X-ray energy range. A systematic study was undertaken by the authors to study the resolution and sensitivities achievable on using Gadolinium based image intensifier systems along with X-rays as the source of radiation. Both performance curves and contrast response curves of such systems were experimentally detennined which is presented in this paper.  [c.443]

The fundamental parameters of radiographic image quality on film are contrast, unsharpness or definition and graininess. In RTR, graininess is replaced by the noise. The quality of the radiological images can be defined as the ability of the image to reflect the spatial variations in the attenuation of X-rays by the examined object. In practice several physical factors such as I) finite source size 2) geometric and spatial resolution 3) beam scatter 4) screen absorption and emission efficiency 5) object motion can degrades the image. Periodic assessment of the image  [c.443]

The sensitivity curves are plots of maximum achieved sensitivity as a function of thickness of the object for a given focal spot size and source to detector distance. The best attainable sensitivity in image intensifier systems is a function of tube voltage, current, scattered radiation and the screen gamma. As a first step, stainless steel plates with thicknesses ranging from 5 mm-30 mm in steps of 5 mm were chosen. These plates had a length of 950 mm and width of 280 mm. The plate is positioned very close and at the center to the LI. tube. The extraneous  [c.444]

It can be observed from the Figure 1 that the sensitivity of I.I. system is quite low at lower thicknesses and improves as the thicknesses increase. Further the sensitivity is low in case of as observed images compared to processed images. This can be attributed to the quantum fluctuations in the number of photons received and also to the electronic and screen noise. Integration of the images reduces this noise by a factor of N where N is the number of frames. Another observation of interest from the experiment was that if the orientation of the wires was horizontal there was a decrease in the observed sensitivity. It can be observed from the contrast response curves that the response for defect detection is better in magnified modes compared to normal mode of the II tube. Further, it can be observed that the vertical resolution is better compared to horizontal which is in line with prediction by the sensitivity curves.  [c.446]

Proximate testing and a product quality control is conducted by an operator, using an object image on a screen, when processing control results using special program, defective areas are marked and measured, including their maximal extent in the direction of X-raying. Then weld  [c.450]

Testing results are fixed in files and, when necessary, represented on a paper or magnetic medium. After completion of a testing process a single file forms a complete image of an object or a weld that can also be brought to a monitor screen or a paper tape in a real image scale. This is most suitable for testing of welds in pipelines of a large diameter. By imposition of an image upon an X-rayed weld one can quickly locate a defective area.  [c.450]

Mode Screen Diameter Center 70 % radius 90 % radius  [c.456]

The sensitivity of the luminescence IP s in the systems employed here decreases with increasing x-ray energy more strongly than in the case of x-ray film. Therefore, this phenomenon must be compensated by using thicker lead front and back screens. The specific contrast c,p [1,3] is an appropriate parameter for a comparison between IP s and film, since it may be measured independently of the spatial resolution. Since the absorption coefficient p remains roughly constant for constant tube voltage and the same material, it suffices to measure and compare the scatter ratio k. Fig. 2 shows k as a function of the front and back screen thickness for the IP s for 400 keV and different wall thicknesses. The corresponding measured scatter ratios for x-ray films with 0,1 mm front and back screens of lead are likewise shown. The equivalent value for the front and back screen thicknesses is found from the intersection of the curves for the IP s and the film value.  [c.470]

Table 1 Equivalent screen thickness for IP s (BAS HI) Table 1 Equivalent screen thickness for IP s (BAS HI)
The object is rotated by a CNC turntable. The detector is a 22 cm Csl fluorescence screen and an image intensifier. The digital data fi om the image intensifier is mathematically projected into a 3D array, where it is being summed according to the angle of rotation and the position in the object. Here, the effect achieved previously by rotating the film is reached by rotating the data the image intensifier generates, [7]. In this way, the array that represents the summation image of the whole 3D examined object is obtained, and different layers inside the object can be chosen for examination. The method has the advantages of real-time digital processing, beside the generation of the 3D tomographic image at a single exposure.  [c.477]

There are two kinds of geometric distortion introduced by the image intensifier, radial distortion and S distortion. Radial distortion is due to the curvature of the input surface of the image intensifier. The mapping of electrons from the curved input surface to the flat output screen causes larger object magnification at the image periphery than at the center. In addition, the projection of objects onto the curved input surface contributes to the total radial distortion. S distortion is due to the surrounding magnetic field, for example, the earth magnetic field or nearby man-made magnetic fields. The severity of the S distortion varies with the position of the image intensifier relative to the magnetic field direction [2, 4]. The transverse component of the magnetic field causes the image to he displaced while the longitudinal field tends to rotate the image. Some minor distortions are introduced by the CCD camera.  [c.485]

The flexible large area screen with photostimulable phosphor called the imaging plate, which temporarily stores the image induced by the ionizing radiation, e g. by X-rays, electrons or other charged particles  [c.505]

There are two principal neutron imaging techniques in NR - direct and transfer (indirect). In the former the neutron converter and the detector are simultaneously exposed in the neutron beam while in the transfer technique only the converter screen is exposed and activated by the neutrons, and transfered out of the neutron beam to subsequently expose the detector. Various types of IP can be used in both of neutron imaging techniques.  [c.507]

Due to the better sensitivity of IP-ND and IP the neutron exposure times could be reduced for a factor about 125 in comparison with the Gd screen/radiographic SR film method. In the later technique neutron exposure time of more than 90 min in the thermal neutron flux of 4.5 10 n cm s are required, while for the obtaining a neutron image of comparable quality using IP-ND the exposure time could reduced to only 10-40 seconds In Fig. 1 NR images of a Incite step wedge, Fe step wedge and BPI and SI neutron standard objects obtained with an IP-ND at neutron fluence of about 1.13 lO cm (Fig. la) and 5.6 10 cm (Fig. lb) are presented. The corresponding values of the recorded signal of the free neutron beam are 655 PSL/mm and only 26 6 PSL/mm . respectively. Both images are underexposed for factor of about 1.5 and 38 respectively. However, the image on Fig. la clearly reveals all three holes in the first 6 steps of the Fe wedge. The thickness of steps varies from 1-9 as 3 mm, 2 mm, 1.5 mm, 1.0 mm, 0.57 mm, 0.5 mm, 0.375 mm, 0.25 mm and 0.125 mm respectively. In the step 7 only 2T and 4T holes (T=step thickness, corresponding hole diameters 0.7 mm and 1.5 mm respectively) and in the step 8 the hole 4T are visible. Ail steps in the Incite calibration wedge can be resolved. Here the film neutron radiograph using single coated fine grained radiographic film and Gd metal screen obtained at neutron fluence of about 2 10 cm reveals also the holes 2T and 4T in the step 8. The NR image obtained with IP-ND at neutron fluence of only 5.6 10 cm still reveals all 3 holes in the first 4 steps and first 6 steps in the Incite wedge. The images of BPI and SI neutron standards can still be used for the neutron beam quality evaluation. The neutron image at so low fluence is rather noisy, however it demonstrates the feasibility of direct NR even with extremely weak neutron sources.  [c.508]

Whatever the method used to screen possible sequences, it is important not to give exclusive attention to the one that appears to have the lowest vapor load or lowest total cost. There is often little to choose in this respect between the best few sequences, particularly when the number of possible sequences is large. Other considerations such as heat integration, safety, and so on also might have an important bearing on the final decision. Thus the screening of sequences should focus on the best few sequences rather th2in exclusively on the single best sequence.  [c.142]

Aerobic digestion is normally capable of removing up to 95 percent of the BOD. Anaerobic digestion is capable of removing less, in the range 75 to 85 percent. With municipal treatment processes, which treat a mixture of domestic and industrial efiluent, at minimum, some disinfection of the efiluent is usually required to destroy any disease-causing organisms before discharge to the environment. Tertiaiy treatment processes vary, but they constitute the final stage of effluent treatment to ensure that the effluent meets specifications for disposal. Processes used include the following a. Filtration. Examples of such processes are microstrainers (a fine screen with openings ranging from 20 to 60 mm) and sand filters. TABLE 11.3 Typical Effluent Quality for Various Receiving Waters  [c.318]

After often a lengthy period (several months) of acquisition and processing, the data may be loaded onto a seismic workstation for interpretation. These workstations are UNIX based, dual screen systems (sections on one side, maps on the other, typically) where all the trace data is stored on fast access disk, and where the picked horizons and faults can be digitised from the screen Into a database. Of vital Importance is access to all existing well data in the area for establishing the well - seismic tie. 2D data will be interpreted line by intersecting line, and 3D as a volume.  [c.20]

Due to the spherical form of the input screen of the image identifyer tube and electromagnetical disturbances the image values are globaly and localy distorted.  [c.13]


Figure 8 describes the results of the VIGRAL algorithm as displayed on the screen after processing. The graph at the top plots the results of the tirae-of-flight and amplitude measurements from the B-scan empty circles show the ToF measurements at each X position. The filled circles show the corresponding peak amplitude. The graph on the lower right hand comer shows the resulting extent and position of the flaw in the plane of the measurement the X-Y plane. In the example shown, the surface of the flaw is located at a  [c.167]

In radiography the X-ray signal from the path passing beside the object. So, is not interesting, see figure 7. To increase detectability of defects the objective is to maximise the difference between signal S2, that penetrates the object and defect, to signal St, that penetrates the object but pass beside the defect, relative the noise. For CT, on contrary, image reconstruction requires estimation of the number of X-ray photons impinging on the object, lo- It is normally estimated with the signal So- Consequently, So has to be within the detector dynamic range. This alters the optimisation philosophy for CT to maximising the contrasting differences between signals from different X-ray photons paths, S and S2, penetrating the object relative the estimate of So- To find optimal settings it is only necessary to maximise the signal-to-noise ratio in the detector entrance screen, SFR proj since it has a linear relationship to SNRas,ct in the final CT-image. SNR jtprqj was defined as  [c.212]

Further instruments followed from our stable, the next was the HALEC crack detector in 1970, which again is still in use today and the engineer who designed it is still with the company. We were among the first to put microprocessors into instruments to replace front panel switches, and later to put menus on-screen with settings stored in memory. At one point we were working on a digital display technology which we knew we could not sell due to the high cost of memory. Imagine our feelings when at the end of the development project the cost of memory had fallen to a fraction of what it was at the beginning. We had a modest success on our hands, more by luck than anything else. But everyone needs to be lucky from time to time and we have enjoyed rather a good share of good fortune.  [c.273]

The X-ray TV introscope (XTVI) developed in Introscopy Institute in accordance with [1] enables to detect with high resolution pores, cavities, metal and nonmetal inclusions, poor fusions in welded joints and cracks, whose opening plane coincides with X-raying direction. It can also be used to identify geometries of internal details, to detect foreign inclusions, discontinuities, external defects, inaccessible for external inspection, like cuts, bums -through, etc. Introscope operation principle is based on exposure of objects to X-radiation, conversion of a latent X-ray image into a TV signal with subsequent computer processing and image visualization on a monitor screen.  [c.449]

Due to the fact that the area of converters is of limited dimensions, X-raying of large-size objects is usually performed sequentially by sections. In introscope a product is moved by an automatic positioning unit in a control field in accordance with developed methodics of X-raying in a start-stop mode. A selected section of a product is positioned in the field of X-raying and exposed. Using a computer one can select the most informative frame of a TV image, digitize and record in into a separate file on a computer disk and then bring it on a monitor screen. Then the process is repeated cyclically up to the end of a testing algorithm. For testing of circular welded joints of pipelines under field conditions a new automatic positioning unit has been developed that can rotate a radiation source and an X-ray TV camera, mounted axially to it, round a tube.  [c.450]

There are several discussions about the new general rules for radioscopy (prEN 13068) in the committees CEN TC138 WGl AHG 1 and nw Va. The major contradictions are the minimum requirements for the spatial resolution of the systems. Two sources of unsharpness have to be considered F the geometric unsharpness which is defined by the wall thickness in the standards (EN444, EN1435) and 2 the inherent unsharpness which depends on the y/x-ray energy, wall thickness and front screen thickness and -material. Table 2 gives typical values, measured for the inherent unsharpness of film screen systems. Corresponding to this table the IP s can be compared with the film systems in relation to the energy range of application. Finally there exist an proposal to define the minimum spatial resolution for radioscopy in dependence on the wall thickness. CR can achieve much better resolution then required for radioscopy. But in the range of very thin wall thicknesses and low energy CR must be used also with the microfocus technique in the magnifying mode.  [c.472]

The surface visualization is only a representation of areas in the sample volume, defined by a user specified threshold for the local X-ray absorption and the so called Isosurface based on it. The Isosurface represents the sample at the given threshold and is constructed automatically with the Marching Cubes algorithm [15]. This Isosurface is arranged, illuminated and rendered onto the computer screen and so very realistic views of the data at the given threshold are possible. The conversion from the three-dimensional volumetric information to the two-dimensional surface is a reduction of the data. The surface rendering process is therefor carried out by OpenGL compatible graphics hardware to achieve realtime manipulation possibility (Fig. 4 a).  [c.495]

The use of IP might improve or facilitate several already known special NR experimental techniques, where insufficient neutron source intensity often poses a problem for the film based neutron imaging. A typical example is the hydrogen sensitive neutron radiography (HYSEN) (5) the transfer technique might facilitate the hydrogen detection and improve the detection sensitivity. For resonance and fast neutron imaging new converter screens in combination with IP can be effectively employed (7). Completely new NR techniques can be conceived, such as radiography with the mono-energetic neutron beams produced by resonance scattering and using matched resonance neutron detectors (6). Recently first radiographs with mono-energetic neutrons produced by resonance scattering on W and using the W converter screen in combination with the IP have been obtained, demonstrating the feasibilty of the proposed new method (7).  [c.510]

See pages that mention the term Saccharum : [c.415]    [c.242]    [c.350]    [c.353]    [c.382]    [c.228]    [c.168]    [c.211]    [c.450]    [c.509]    [c.509]   
Handbook of hazardous chemical properties (2000) -- [ c.363 ]