Error Corrections in a Sampling Sliding Along a Pulse Envelope Based on Decoding Tables

Code combinations of 2 ⁿ symbols +1 and –1 suggested for identification of characteristic features leading edge, trailing edge, maximum, minimum, horizontal portion, start of leading edge, end of leading edge, start of trailing edge, and end of trailing edge in a binary-code envelope of a pulse measured by an eddy-current transducer (ECT) scanning a tested surface generate a group code. This group code ensures for four levels of noise immunity the maximal likelihood in identification of reference sequences distorted by noise. The structure of a product code, which is also generated by the reference fragments, results in a higher capability of correcting for errors in moving samplings of signal envelopes, in particular, it reduces the degree of uncertainty in identification of the most important features of ECT pulses. The paper suggests simple decoding algorithms and regular logical structures that provide a high efficiency of the procedure eliminating errors in binary sequences of coded envelopes.     

A Helical Magnetic-Cumulation Generator with a Compact Transformer

Experimental data on a helical magnetic-cumulation generator with an output step-up transformer formed by two coaxial solenoids is presented. The inner diameter of the helix is 50 mm. Compared with the transformers described earlier, this transformer has a smaller size. The transformer can feed an energy of 1 kJ into a 100-H high-impedance load.     

Development of a knowledge-based manufacturing modelling system based on IDEF0 for the metal-cutting industry

This paper looks into a new area for knowledge-based system application, that of manufacturing modelling. The objective is to develop a knowledge-based manufacturing modelling system that can be used to build company-specific as-is and to-be IDEF0 models, and can therefore greatly reduce the turnaround time and effort involved in IDEF0 modelling of manufacturing systems, which can be time-consuming if done manually or even with the aid of a commercially available software package like DESIGN/IDEF. This is especially so when the systems being modelled are large and complex. Besides, there is also the inconsistency problem associated with conventional IDEF0 modelling systems owing to the terms and terminologies in IDEF0 not being precisely defined, and hence being subject to individual interpretations. In this paper, a knowledge-based IDEF0 modelling system that can not only automate the tiresome and time-consuming process of manufacturing modelling but can also eliminate the inconsistency problem is proposed. The paper explains the knowledge-based approach to automated generation of IDEF0 models, and also identifies the kinds of domain knowledge that are required for the construction of the knowledge-based manufacturing modelling system.     

A Vacuum Feedthrough Insulator at a Voltage of ∼1 MV

The design and results of tests of a vacuum feedthrough insulator for a pulsed electron accelerator with a voltage of 1 MV, a current of 20 kA, and a half-height voltage-pulse duration of 400 ns are presented. A method for distributing the voltage over the sections of the insulator due to an electron emission from specially created surfaces is proposed.     

Plastic snapfit fastener design

This paper presents a systematic procedure for selecting and designing snapfits integrated into plastic parts. A classification is proposed based on the geometry of the parts to be assembled and the ease of dismantling. The part geometry influences the type and shape of the snapfit. Depending on the space available, recommendations are made for choosing from a classical straight beam shape, a tapered shape, an L shape and a U shape. The snapfit fastener may be separable if so designed. A distinction should be made between: dismantling with or without a tool (screwdriver or specialised tool); access to the insertion face only; access to insertion face and opposite or lateral faces.     

Modelling and forecasting industrial innovations via the transfer function S-shaped learning curve

Algorithms are derived for the four-parameter transfer function S-shaped curve, using a least-squared-error (LSE) method for an exponential function. The S-shaped curve is just one in a family of industrial dynamics learning-curve models of increasing complexity which may be used to replicate and forecast the start-up of industrial innovations.Controlled experiments are undertaken, via simulation of message and noise, to test the modelling and forecasting capabilities of the algorithms. A number of strategies are introduced to improve forecasting performance, such as boots-trapping, sequential and parallel adaptation, and alternatively adopting the simplified three-parameter S-curve model.Four examples of modelling industrial innovations via the transfer function learning curve models are presented. The paper concludes that although there is now the capability to model the general four-parameter S-curve, its applications are limited. This is because simpler (and hence less accurate) transfer function models tend to be more robust.     

Reconstruction of Coordinates of Scintillations in a Large-Size Cylindrical Detector with Radially Arranged Photomultipliers

An algorithm for calculating the scintillation coordinates developed for a large-size coordinate-sensitive detector is developed. The detector based on a liquid scintillator has nine radially arranged -174 photomultipliers. The results of simulation of the dependence of the coordinate resolution at the detector center on -quanta energy between 0.2 and 8 MeV are presented. The experimental data obtained with a collimated beam of -quanta from a ⁶⁰Co source, which irradiated the central part of the detector, were processed by using this algorithm. The -ray spectrum measured by the detector and the results of determining the scintillation coordinates for a -quanta beam are presented. The accuracy of coordinate measurements at the central region of the detector with this algorithm is 10 mm.     

Local High-Frequency Magnetron Reactive-Ionic Quartz Etching

A high-frequency magnetron reactive-ion etching system for the high-speed quartz glass surface treatment is described. The scanning assembly of the magnetron is located in a separate chamber pumped down to a pressure of 10^–2 Pa. This ensures a highly uniform etching and a high magnetic induction on samples, making it possible to reduce the cathode thickness. The quartz etching was studied in SF₆, CF₄, and CHF₃ with the magnetron operation with and without scanning. The maximum etching rates of 1.6 m/min (with scanning) and 4.2 m/min (without scanning) were attained in CHF₃ with a 1-Pa pressure and 700-W discharge power. 150-m-depth 4-mm-diameter pits were obtained by the quartz etching without scanning. With an increase in the pit depth from 150 to 250 m, the etching rate was reduced from 4.2 to 2.5 m/min.     

Thickness Measurements of Thin CsI(Tl) Scintillators

A -activation method for measuring the thickness of thin CsI(Tl) polycrystalline films deposited by evaporation on large-area (150 cm²) backings is described. Scintillators specially prepared to be used in the FASA installation as detectors of intermediate-mass fragment multiplicity were measured. It was shown that the distribution of the film thickness along the scintillator surface can be determined by -activity scanning. It has been shown that the film thickness decreases from the middle of the backing to its periphery by 25% for scintillators with a linear size of 140 mm.     

A novel representation of tandem systems with inter-stage storage applied to on-line system monitoring

One of the goals of operating a tandem manufacturing system with finite inter-stage storage and asynchronous operations is to meet the demand without over-producing, under-producing or carrying large quantities of material in storage. We believe that analysing the operation of such a system on a real-time basis helps achieve this goal. The first step in this real-time analysis would be to quantitatively associate the causes and effects of over-production or under-production as they occur. This requires determining the cumulative effect that the performance that any stage has on the system, based on its history, the current system state and the interrelationships between the stages. This paper proposes a method which first represents uniquely and completely each stage and surrounding storage as an element. While this system, which consists only of this simple type of element functions in exactly the same way as the original one, each element is put into an ideal world for decoupled measurement. Though an element behaves in exactly the same way whether it is in the ideal world or in the real world, the elapsed times in the two worlds since the beginning of production can be different, since the responses (occurrences and durations of the blockings and starvations) of the two worlds can be different. A phase parameter is introduced for each element to represent this difference. Once the formation of the phase parameter of the output element is formulated, quantitative relationships between causes and effects of over-producing or under-producing can be explained as they occur.     

Assessment of the Hazard Level (Depth) of Flaws Using a ВД-12НФМ Eddy Current Flaw Detector

The operation features and the main technical characteristics of the -12 eddy current flaw detector are considered. A method is proposed for testing complex-shaped parts with the use of holding attachments and a specialized transducer with a slanted sensitive element. The capabilities of the device in assessing the hazard level (depth) of a flaw are shown. The distinctive features of the -12 eddy current flaw detector are presented.     

Influence of Radiation on Luminescence Properties of Quartz Glasses and Fibers

The results of an X-ray luminescence investigation of K and K-1 quartz glasses and quartz fibers of variable composition and sizes exposed to X-ray doses of 10²–10⁷ Gy are presented. Two luminescence bands at 410 and 450–470 nm were discovered as a result of an analysis of the X-ray luminescence spectra of glasses and fibers and comparison of the experimental data in glass spectra. The possibility of using the data obtained for quartz glasses for interpretation of the results referring to quartz fibers is considered. The dose dependences of the X-ray luminescence intensities measured for each luminescence band were examined to clear up the nature of the relevant centers. A luminescence band of 410 nm in quartz glasses and fibers is suggested to be due to oxygen-deficient Ge centers damaged during -irradiation, and a 450- to 470-nm band, due to E"-centers, the number of which increases with the absorbed dose. A protective role of OH groups against the generation of luminescent centers induced under the -irradiation of quartz glasses and fibers was confirmed.     

A Subnanosecond Voltage Divider on Coupled Lines

The divider consists of two electrically and magnetically coupled coaxial lines inserted one into the other and having a single common outer conductor. One is an oil-filled line transmitting the main high-voltage pulse, and the other is a low-impedance measuring line, whose input is connected through a cable to the input of an oscilloscope. The experiment has confirmed the calculated division factor of 300 and a reproduction of the shape of the recorded pulse by the divider without distortions. The divider was used for recording bipolar pulses with ±120-kV amplitudes, a duration of 0.8 ns, and a rise time of 0.2 ns.     

Detection of the Increment of an Instantaneous Phase in a Long-Base Laser Meter of Small Vibrations

A phase meter for processing signals of a laser meter of small displacements and vibrations at long base distances is described. Vibrations of objects are transformed into small increments of a signal phase at an RF carrier, which are detected by the phase meter and are outputted as signals proportional to microvibrations in the acoustic range. At a given carrier frequency f _c = 10.7 MHz, vibrations are detected within a band f = 3 kHz. Such vibrations produce phase fluctuations of 10^–42, which correspond to magnitudes of 1 nm for a laser wavelength 10 m.     

A Self-Initiated Periodically Pulsed Light Source on Chlorine and Krypton Chloride Molecules

An electric-discharge light source, operating in the spectral range of 170–270 nm on a system of bands of Cl₂ ( = 200 and 257 nm) and KrCl ( = 222 nm) molecules is described. The radiator is pumped by a low-pressure volume discharge in a spherical anode-flat cathode system of electrodes with an interelectrode distance of 6 cm, so that the plasma has no contact with the quartz envelope of the lamp. The working mixtures are P(Kr)/P(Cl₂) = (40–640)/(40–280) Pa. When a dc voltage U 1 kV is applied to the discharge gap, a volume discharge exists only in a periodically pulsed mode (f = 0.1–50 kHz) and represents a source of short-wave radiation with a cylindrical working surface (1 cm in diameter and 6 cm long) and a mean radiation power of 3 W.     

Automated Devices for the Testing of Mill Rolls

Multichannel -type devices developed at TsNIITMASh for the automated ultrasonic inspection of cylindrical objects, such as mill rolls, shafts of turbines and compressor units, circular welded joints of thick-walled shell rings, etc., are described. These devices feature from two to eight acoustoelectronic channels. Acoustic contact occurs through industrial water. The testing is performed under workshop conditions; the object being inspected is rotated by a turning lathe or any other handling mechanism. Sonication is simultaneously performed by piezoelectric transducers (PETs) with input angles of 0, 40, 50, 60, and 70° and also by surface and head waves in order to reveal surface and subsurface flaws. A wide-span eddy-current transducer of special design is also used for this purpose. All data are stored in flash memory and retrieved on a PC located in an office. The inspection results are displayed as C- and B-type scanning defectograms. Moreover, it is possible to obtain an isometric image of flaw zones. -type devices have been used for over one and a half years in two workshops at OAO Severstal'.     

How Radical Was IT-Enabled BPR? Evidence on Financial and Business Impacts

Many large claims have been made about the payoffs that can and must be made from business process reengineering (BPR). Information technology is usually ascribed a critical role in BPR success. There is still a shortage of detailed information on the BPR phenomenon in terms of costs and results. This paper uses data from 168 UK-based organizations surveyed in the BPR heyday (1994–1996 period) to establish the size of expenditure, types of costs, and the types and size of benefits anticipated and experienced among these organizations. The majority were found to be aiming low and hitting low, though there was evidence of a small minority of organizations achieving something approaching what could be described as breakthrough results. The reasons for these results are discussed in detail and are related to the wider literature.     

A Mediator Spectrometric Unit

The mediator unit (mediator) generates a strobe pulse when a scintillation signal is at its maximum (peak moment). The strobe pulse starts the analog-to-digital converter, which performs digitization on a special command. The parameters of the mediator circuit presented are optimized to handle the signals from the detection unit, which comprises a CsI(Tl) scintillator, a silicon p–i–n photodiode, and a squaring amplifier. The maximum input-signal amplitude is 5 V, and the time of rise to the maximum is 7 s (quasi-Gaussian signal). When such signals are used, the strobe pulse is shifted in time with respect to the signal peak by 5 ns if the amplitude of the analyzed signals varies from 5 to 0.2 V. The unit is tested in operation (with minimal circuit alterations) over a rise-time range from 1 s (NaI(Tl)) to 20 s. The mediator includes a baseline-potential restorer and an adjustable-threshold comparator. Owing to these features, the mediator can also be used as an amplitude integral discriminator and can operate from signal sources with unstable base levels, including systems that require a signal time lock. When the recorded signals are superimposed on the leading and trailing edges, a considerable part of the superimposed signals is rejected.     

Burr detection by using vision image

In this paper, a practical force model for the deburring process is first presented. It will be shown that the force model is more general than Kazerooni's model and it is suitable for both upcut and down-cut grinding. In terms of this force model, an algorithm of burr detection by using a 2D vision image is proposed. In the burr detection algorithm, the relevant data of burrs, such as frequency, cross-section area, and height are simplified so that they are functions of the burr contour only. Then, a fast tracking method of the burr contour (BCTM) is developed to obtain the contour data. Experiments show that the BCTM of this passive (i.e. without lighting) image system can be as fast as 18.2 Hz and its precision is 0.02 mm, so online burr detection and control by using the vision sensor is feasible.Nomenclature A _burr cross-section area of the burr - A _chamfer cross-section area of the chamfer - A _n proportional factor - A _work cross section area in the contact zone while deburringA _work=A _burr+A _chamfer - w cutting width - w _root thickness of the root of the burr - a depth of cut - a _root burr heighta _root=a(w _root) - C ₁ static cutting edge density - D equivalent wheel diameter - d _s wheel diameter - d _w workpiece diameterD=d _w d _s/(d _w±d _s)D=d _s andd _w for the deburring process - F _h horizontal grinding force - F _v vertical grinding force - F _n normal grinding force - F _t tangential grinding force - F _n(K) normal grinding force of the Kazerooni's model - F _t(K) tangential grinding force of the Kazerooni's model - F _o threshold thrust force - f _burr burr frequency - f _n normal grinding force per active grain - f _t tangential grinding force per active grain - f _r first resonant frequency of the robot - f _tool resonant frequency of the end-effector at the normal direction - exponential constant for describing the edge distribution = [(1 +n) + (1 –n)]/2 = (1 +n)/2 for = 0 [21] - K proportional factor of the force model of the grinding processK =A _n ^1–n / - K ₀ specific contact force per contact length - K ₁ specific chip formation force per contact length - V _s wheel speed - V _w workpiece speed - _w metal-removal parameter - K ₂ specific metal-removal parameter per wheel speedK ₂ = _w/V _s - K _c specific chip formation force per area - K _f specific friction force per area - k constant for the parabolic burr - k ₁,k ₂,k ₃,k ₄ constants for the circular burr - L contact width between the wheel and the workpieceL is equal to the chamfer's hypotenuse length, orL=w _root when there is no chamfer - l contact length - l _k contact length between the wheel and the workpiece - m exponential constant for describing the edge shape 0m1m=1 for the deburring process [21] - N _dyn number of engaged cutting edges per wheel surface - n exponential constant for describing the cutting process 0n1n=1 for the pure chip formation process andn=0 for the pure friction process [22] - average contact pressure - p exponential constant for describing the relationship between the static cutting edge and the wheel surface depth 1p2p=1 for linear case [21] - Q magnitude of the individual chip cross-section in the contact zone - r radius of the circular burr - Z _w metal-removal rate - ,, exponential constants for describing the edge distribution [21] = (p –m)/(p + 1) = 0 form = 1,p = 1 =p/(p) + 1 = 1/2 forp = 1 = (1 –n) = 1n/2 for = 1/2 - actual contact area between the wheel and the workpiece - coefficient of the sliding friction - variable of the contact angle - _k maximum contact angle - _m mean rotating angle - _t half of the tip angle of the grains - ratio of tangential chip formation force to the normal chip formation force. Usuihideji has pointed out that = /(4tan_t) [29]     

Multiple Linear Regression of Complex Permittivity of a Till at Frequency Range from 200 MHz to 400 MHz

The complex permittivities of 40 compacted natural clayey till specimens at various water content, density and pore fluid salinity as independent variables are analyzed. A multiple linear regression model is constructed and the statistical analyses for the relative permittivity (') and dielectric loss ( ')-regression equations in the frequency range from 200 to 400MHz are performed. It is concluded that the multiple linear regression model of the complex permittivity is highly significant. The coefficient of determination (R ²) and standard error (SE) of the linear regression equations vary with frequency. At 200MHz for ' -regression and 300MHz for '-regression, all three independent soil variables are significant at a probability of 0.95. The complex permittivity regression model with two variables at 250MHz for 'and 350 for '-regression equations. Upon further study on the effect of soil mineralogy to the complex permittivity, the results obtained in this study may serves as the principle of the characterization of subsurface and detection of soil and groundwater contamination.