The Present

Thanks to the perfecting of chemical, physical, and enzymic methodologies during the past few years (for reviews, see Refs. 8,10,13,14, 17,27, and 28), the structures of glycans have been determined by the dozen (for reviews, see Refs. 8, 10, 11, 13, 14, 16, 17, and 29-34). In particular, the development by our laboratory, in association with the Dutch group of J. F. G. Vliegenthart, of a process based uniquely on permethylation and 360-MHz, n.m.r. spectroscopy (see later) allows the rapid determination of glycan structures of the N-acetyl-lactosa-minic type (see Fig. 3). 

whereas a period of several years had been necessary for the determination of the first, definitive structures of glycans (the glycans of serotransferrin35,38 and of IgG immunoglobins37), a matter of weeks 

Structure 1 of Glycans O-Glycosylically Conjugated Through the Linkage a-GalNAc-(l— 3)-Ser or Thr 

Origin of glycans Galactose 2-Acetamido-2-deoxy galactose References 

N Blood-group f a-NeuAo(2— 3) 1 a-N euAo(2— 3)-Gal none none 47,62,63 64 

Since 1973, progress in the petrochemical industry has been rather like a roller-coaster ride. Major rises in the price of crude oil in 1973-1974 and again in the late 1970s fed through most quickly into petrochemical products, affecting demand worldwide. This period saw many proposals to replace petroleum-based chemical feedstocks, and even hydrocarbon fuels. 

Despite some closures, postponements and cancellations of new projects during the downs , the ups prompted new investment, much of it in the less well-developed countries of the Far East, Middle East, Africa and Central/South America to reduce their dependence on imports. New construction is almost inevitably in very large blocks the total output from a petrochemical complex may exceed 1 million tonnes (Mt) per annum. The fall in export potential contributed to something like a 60% excess of nominal capacity over actual requirements in both Europe and the U.S.A. during 1982, and 1982 U.S. production figures for major chemicals were only slightly higher than for 1973. 

The price of oil fell in 1986, providing a boost during a further period of growth, but the late 1980s saw the onset of another worldwide recession. New investment continued, especially in the Far East outside Japan Japan s share of Asian ethylene capacity has fallen from 75% to 45% in the last 10 years. (South Korean ethylene production tripled between 1990 and 1993 to l 5Mt per annum, for example.) In contrast, the chemical industries of Eastern European countries and the former Soviet republics are heavily depressed, though we may soon see new investment targeted initially at export markets. 

In the West the situation remains rather fluid while many downstream products remain depressed, polyolefins and other thermoplastic resins are showing continued growth, leading to increased demand for the major intermediates. 1993 saw U.S. production reach 18 7 Mt ethylene, 10 2 Mt propylene, 5 6 Mt benzene, 15 6Mt ammonia and 4 8 Mt methanol In western Europe, now including all Germany, 1993 production figures for ethylene and propylene were over 15Mt and 9Mt, respectively. 

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At moderate densities. Equation (3-lOb) provides a very good approximation. This approximation should be used only for densities less than (about) one half the critical density. As a rough rule, the virial equation truncated after the second term is valid for the present range... 

Thus the appropriate placement of heat pumps is that they should be placed across the pinch. Note that the principle needs careful interpretation if there are utility pinches. In such circumstances, heat pump replacement above the process pinch or below it can be economic, providing that the heat pump is placed across a utility pinch. Such considerations are outside the scope of the present text. 

From graph theory the main result needed in the present context is that the number of independent loops for a graph is given by ... 

Figure 8.4 shows the cost tradeoffs for the present case. At high conversions, the raw materials costs due to byproduct formation are dominant. This is so because the reaction to the undesired... 

Net present value (NPV). Since money can be invested to earn interest, money received now has a greater present value than money received at some time in the future. The net present value of a project is the sum of the present values of each individual cash flow. In this case, the present is taken to be the start of a project. 

The flash points obtained experimentally according to the different procedures differ slightly. The present estimation refers to the flash point called the closed cup method. 

A Monte Carlo simulation is fast to perform on a computer, and the presentation of the results is attractive. However, one cannot guarantee that the outcome of a Monte Carlo simulation run twice with the same input variables will yield exactly the same output, making the result less auditable. The more simulation runs performed, the less of a problem this becomes. The simulation as described does not indicate which of the input variables the result is most sensitive to, but one of the routines in Crystal Ball and Risk does allow a sensitivity analysis to be performed as the simulation is run.This is done by calculating the correlation coefficient of each input variable with the outcome (for example between area and UR). The higher the coefficient, the stronger the dependence between the input variable and the outcome. 

What we have calculated is the present value (at a particular reference date) of a future sum of money, using a specified discount rate. In any discounting calculation, it is important to quote the reference date and the discount rate. 

The cashflow discussed in Section 13.2 did not take account of the time value of money, and was therefore an undiscounted cashflow. The discounting technique discussed can now be applied to this cashflow to determine the present value of each annual cashflow at a specified reference date. 

The total undiscounted cash surplus (the ultimate cash surplus) is 190 m. The total discounted cash surplus ( 24.8 m) is called the net present value (NPV) of the project. Since in this example the discount rate applied is 20%, this figure would be the 20% NPV also annotated NPV(20). This is the present value at the beginning of Year 1 of the total project, assuming a 20% discount rate. 

One way of calculating the IRR is to plot the NPV against discount rate, and to extrapolate/ interpolate to estimate the discount rate at which the NPV becomes zero, as in the Present Value Profile in Figure 13.16. The alternative method of calculating IRR is by... 

Although the presented results prove the efficiency of radioscopy, this system have certain characteristics which justify to develop and employ further process integrated testing systems. One of this characteristics is that the integration of radioscopy in industrial applications is doubtful because of reasons of radiation protection. This means, that the results from radioscopy should rather be used to fit other systems (acoustic emission analysis or temperature analysis) for industrial applications. 

The authors thank the german research community (DFG) for the support of the presented investigations whieh were realized inside the Special Research Area 326, named, J rocess Integrated Quality Control with Quality Information System for Metallic Parts in Mechanical Engineering, and special thanks to the scientific bilateral project between Brazil and Germany supported by the CNPq, KFA and DLR to realize the presented investigations in advanced radioscopy and tomography. 

The paper focuses on the presentation and discussion of the results of the application of long term, continuous, AE structural monitoring to 2 large superheated (SH) steam outlet headers, belonging to 2 different full-size (600 MW, supercritical multifuel) ENEL power units. Continuous AE surveillance of the 2 SH headers started in October 1996 and is still ongoing. 

The present work was done with the aim to evaluate the efficiency of the acoustic emission method as a diagnostic tool for analysing a carbon plastic composite and its adhesive joints. The samples of the carbon plastic type UKN-5000 were used in the test. Non-defected samples and samples with artificial defects were tested. 

Case-Based Reasoning. Case-Based Reasoning (CBR) systems base their solutions on previously solved problems (cases) which are stored in a case-base [Watson Marir, 1994]. When a new problem is presented to a CBR system a similar case(s) is/are retrieved from the case-base. Depending on the differences between the retrieved and the presented problem the retrieved solution may have to be more or less adapted to obtain a solution to the new problem. The solved problem may be retained in the case base if deemed useful. 

Finally, it is shown in terms of the presented example that the proposed adaptive reconstruction algorithm is valuable for image reconstruction from projections without any prior information even in the case of noisy data. The number of required projections can be determined by investigating the convergence properties of the reconstruction algorithm. 

There are different possibilities to address the above set of equations which can be solved provided 2in > 3i, and provided the measured ToF information varies between measurement points. For the purpose of the present work we have taken two simplifying assumptions (a) one virtual source predominates at each measurement point, m and (b) each virtual source predominates at more than one measurement point. Note that assumption (b) ensures the condition 2m > 3i that is necessary to obtain solutions for Equations (2) and (3). These assumptions are justified by considering the defect surface as an acoustic secondary field source. At each measurement point the transducer predominantly receives signals from an... 

Segmentation method based on the analysis by Co-Occurrence Matrix is developed. We try to increase the quality of the obtained results by means of the application of two dimensional (2D) processing. We use Co-Occurrence Matrix for ultrasonic image segmentation. This tool, introduced by Haralick (1), was selected for the present study as several general considerations were favourable ... 

The war itself also drove the development of improved and miniaturised electronic components for creating oscillators and amplifiers and, ultimately, semiconductors, which made practical the electronic systems needed in portable eddy current test instruments. The refinement of those systems continues to the present day and advances continue to be triggered by performance improvements of components and systems. In the same way that today s pocket calculator outperforms the large, hot room full of intercormected thermionic valves that I first saw in the 50 s, so it is with eddy current instrumentation. Today s handheld eddy current inspection instrument is a powerful tool which has the capability needed in a crack detector, corrosion detector, metal sorter, conductivity meter, coating thickness meter and so on. 

The purpose of the nondestructive control consists in detecting local modifications of the material parameters which, by their presence can endanger the quality of the half-finished or finished products. The electromagnetic nondestructive control permits to render evident surface and subsurface discontinuities in the electroconductive material under test. The present tendency of this control is to pass from a qualitative evaluation (the presence or absence of the material discontinuities which give at the output of the control equipment a signal higher or at least equal to that coming from a standard discontinuity whose shape and severity has been prescribed by the product standards) to a quantitative one, which enables to locate as exactly as possible the discontinuity and to make predictions over its shape and severity. 

The paper presents the results from systematic comparisons of contrast and resolution obtained with different types of radiation sources on steel thicknesses from 5 to 40 mm. These results have been taken into account with the definitions of the European standard for radiographic inspection of weldments (EN 1435) that is approved since 1997. Conclusions from practical investigations on pipe line sites, in petrochcemical plants and in nuclear power stations will be discussed as well. Furthermore, the presentation will stipulate a variety of advantages obtained from the new source in terras of coUimation and radiation protection. 

For some years now, standards for radioscopic applications have been in the drafting stage. This paper will discuss the present state of the preparations that the ad hoc working group "Radioscopy" of IIW, CEN and ISO is involved in. 

The method developed in the present study is based on the principles of the above mentioned technique. 

Due to the technical limitations of the present equipment, some blurring of the images was caused by the stability of the turntable rotation axis and its horizontal leveling. 

It was found that that in the case of soft beta and X-ray radiation the IPs behave as an ideal gas counter with the 100% absorption efficiency if they are exposed in the middle of exposure range ( 10 to 10 photons/ pixel area) and that the relative uncertainty in measured intensity is determined primarily by the quantum fluctuations of the incident radiation (1). The thermal neutron absorption efficiency of the present available Gd doped IP-Neutron Detectors (IP-NDs) was found to be 53% and 69%, depending on the thicknes of the doped phosphor layer ( 85pm and 135 pm respectively). No substantial deviation in the IP response with the spatial variation over the surface of the IP was found, when irradiated by the homogeneous field of X-rays or neutrons and deviations were dominated by the incident radiation statistics (1). 

Concerning the spatial resolution of NR images the present IP are not adequate to the best film based direct neutron imaging techniques. However, with time-and the development of new IP technology there are good possibilities to improve the inherent unsharpness of the IP systems to the level even better than with Gd/film combination ... 

The accuracy of the presented methods was verified using test pipes with various diameters and wall thickness of which the wall thickness was measured independently using a slide-rule. Both on film and on the monitor the wall thickness could be determined within an accuracy of ca. 0.2 - 0.3 mm. 

The investigations show that the microfocus high speed radioscopy system is suitable for monitoring the hard particle transport during laser beam dispersing. It is possible to observe and analyse the processes inside the molten bath with the presented test equipment. As a consequence a basis for correlation with the results of a simulation is available. 

Figure I represents a two-dimensional damage distribution of an impact in a 0/90° CFRP laminate of 3 mm thickness. Unlike in ultrasonic testing, which is usually the standard method for this problem, there is no shadowing effect on the successive layers by delamination echos. With the method of X-ray refraction the exact concentration of debonded fibers can be calculated for each position averaged over the wall thickness. Additionally the refraction allows the selection of the fiber orientation. The presented X-ray refraction topograph detects selectively debonded fibers of the 90° direction.

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