Main Principle Of Operation Research Articles

An expert system concept for diagnosis and monitoring of gas turbine combustion chambers

In this paper, the main principles of operation, the conceptual design and the development of an expert system for fault diagnosis and monitoring of gas turbine combustion chambers are presented. The concept of the gas turbine chamber expert system is based on the monitoring of the spatial and temporal distribution of the heat flux inside the combustion chamber and the simultaneous comparison of respective readings of diagnostic variables with values obtained through numerical model simulation of different situations which lead to the malfunction of combustion chamber and deterioration of its performance. The demonstration of the expert system will be performed at the VTI (All Union Energy Institute, Russia) gas turbine combustion chamber test facility.

A Statistical Sampler for a New On-Line Analog Test Method

This work shows a new strategy to the on-line test of analog circuits. The technique presents a very low analog overhead and it is completely digital. In the System-on-Chip (SoC) environment the on-line test can be developed by using processing power already available in the system. As all the signal processing is done in the digital domain, it allows use of a purely digital tester or a digital BIST technique. The main principle of operation is based on the observation of statistical properties of the circuit under test. Since it has low analog power and performance overhead, the proposed technique can be used to analyze the output of several stages of complex analog systems without the use of switches or analog multiplexors for reconfiguration, and no additional AD converter is needed. This paper presents the fundamentals of the proposed test method and some experimental results illustrating the operation of the Statistical Sampler concerning linear analog systems.

A computational methodology for shape optimization of structures in frictionless contact

This paper presents a computational methodology for shape optimization of structures in frictionless contact, which provides a basis for developing user-friendly and efficient shape optimization software. For evaluation it has been implemented as a subsystem of a general finite element software. The overall design and main principles of operation of this software are outlined. The parts connected to shape optimization are described in more detail. The key building blocks are: analytic sensitivity analysis, an adaptive finite element method, an accurate contact solver, and a sequential convex programing optimization algorithm. Results for three model application examples are presented, in which the contact pressure and the effective stress are optimized.

Transmission line balanced inductive plasma sources

A new class of transmission line balanced inductive plasmasources having discrete inductive zones is reviewed. The problems ofundesirable capacitive currents, azimuthal non-uniformity and the energyefficiency of inductive plasma sources are considered and basically solved.The main principles of operation, discharge performance and the mostinteresting experimental observations are discussed.

Construction and investigation of a post-capillary reactor for trace metal analysis by capillary electrophoresis

This paper describes the construction and investigation of a post-capillary reactor for the determination of trace metals by UV–Vis absorption after formation of intensely coloured complexes. A short review of the present published work on post-capillary systems is followed by a detailed description of the fabrication and performance of a post-capillary reactor. The main principle of operation is based on the infusion of the colorimetric reagent into a small 50 μm gap between the separation capillary and the reaction capillary. The gap is enclosed by a permeable membrane and the flow of reagent is aided by a slight overpressure in the post-capillary reactor cell. Careful choice of colorimetric reagent, electroosmotic flow and pH was required to prevent the post-capillary reagents migrating in the wrong direction. Two reagents were studied in detail, namely, xylenol orange and 4 (2-pyridylazo)resorcinol (PAR). The best separation and detection characteristics were obtained with PAR for Cu, Cd, Co, Ni, Zn and Mn. Good linear calibrations were obtained down to the 0.1 ppm level for all the metals except Cu.

Electromagnetic inductance tomography (EMT): sensor, electronics and image reconstruction algorithm for a system with a rotatable parallel excitation field

The main features and principle of operation of an electromagnetic inductance tomography system are described. The system can image the distribution of electrically conducting and/or magnetically permeable materials and is analogous to the other electrical tomography systems which measure capacitance or resistance. The paper presents a nonintrusive system with a rotatable parallel uniform excitation magnetic field which improves the detectability at the centre of the object space with respect to that near the periphery. The sensor construction, electronics design and image reconstruction are described. A novel electronic compensation scheme is used to condition the output signals from the sensor. This scheme subtracts the empty space background field measurements and consequently increases the overall dynamic range of the data acquisition system. An image reconstruction technique based on a correlation method is described and some images are presented.

A novel technique for the polarized atomic-beam targets production

A novel technique for the polarized atomic-beam target production is suggested. Using this technique shows promise of obtaining the polarized internal beam targets from a wide region of elements with densities of 10 11 – 10 12 atoms/cm 3. It combines the developed new approach to the supersonic internal gas-jet target design with a classical atomic beam method of hyperfine state selection in inhomogeneous magnetic fields. The main operation principles and advantages of the suggested technique are described. The importance of the experimental study at storage rings of spin-dependent scattering of polarized electrons and protons on polarized nuclei is noticed.

Homogeneous nucleation in a laminar flow diffusion chamber: The operation principles and possibilities for quantitative rate measurements

The laminar flow diffusion chamber technique for experimental homogeneous nucleation rate measurements is presented. In this type of chamber the flow containing vapor is rapidly cooled and critical supersaturations for homogeneous nucleation are obtained. Here the main operation principles as well as data reduction methods are investigated and the results are applied to dibutyl phthalate (DBP) vapor, which works well in this type of chamber. The nucleation rate has to be calculated using the profiles of saturation ratio and temperature, and using a theoretical expression for the nucleation rate. We have used three different nucleation theories when investigating the experimental nucleation rate: classical nucleation theory, self-consistent correction to classical theory, and the Dillmann–Meier theory. According to investigations in this work the determination of nucleation rate is general and rather independent of the theory used, and therefore the results can be considered reliable. The volume inside which the nucleation event is calculated to take place is examined experimentally. The comparison between model calculations of the actual nucleation volume and experiments show reasonable agreement.

A Fourier transform time-of-flight mass spectrometer. A SIMION calculation approach

A new kind of approach to time-of-flight type spectrometers is presented on the basis of SIMION calculations. The detector studied is a short cylindrical tube capacitor closed with parallel plates at both ends. The main principle of operation is to force ions of equal energy to circulate in the volume between the two tubes on a path of equal radius and measure their flight times pro revolution which corresponds to the frequency of oscillation. By performing spectral analysis on the received signal through transformation from the time domain to frequency space the different masses can be detected. To study the expected performance of the FT-TOF detector, calculations of ion trajectories have been made by varying the dimensions and electric potentials of the electrodes. The effect of the beam position, variations in the angle of entrance and ion energy to the trajectories was calculated to monitor the resolution that is achievable.

An Old Instrument in the New Technological Scenery: The Piston Gauge in Liquid Media up to 1 GPa

A brief historical review, beginning from the first half of the nineteenth century, illustrates the fundamental steps in the development of piston gauges for precise pressure measurements, which were stimulated by the growth of the steam industry and, generally, by hydraulic applications. The main different operational principles and methods for piston gauge characterization are reviewed and the state of the art is discussed from the standpoint of the achievement of the lowest possible measurement uncertainty. An analysis is made of the principal current research problems which are: (i) accurate determination of the effective area of piston-cylinder units at pressures up to several gigapascals; (ii) elastic distortion of piston-cylinder units as a function of applied pressure. This analysis may be a basis for future research work, with a view to acquiring better knowledge of the parameters which limit the accuracy of pressure measurements. Possibilities for the use of modern piston gauges in liquid media to pressures of gigapascal order are summarized.

A new method for the distance control of a scanning Kelvin microscope

A new technique to control the distance between the vibrating Kelvin probe and a sample is described. The main principle of operation relies on the use of the harmonics of the measured displacement current. By a simple signal processing, it is possible to simultaneously monitor, with a high lateral resolution, the topography and the contact potential difference.

Development of a diagnostic expert system for a whipped toppings process

Abstract A diagnostic expert system for the whipped toppings process was developed in an effort to: improve product quality/consistency; improve process efficiency by reducing downtime; improve product yield by minimizing production of marginal product; and standardize diagnostic performance by further educating the plant operators. The expert system is PC-based and has been implemented using VP-Expert, a rule-based development tool, and VP-Info, a database management system. The main principles of operation are as follows. First, the expert system runs off-line and is triggered when the plant operator recognizes, during normal inspection, that a problem exists in the process or with the product. Then, the diagnostic expert system, acting as a consultant to the plant operator, seeks to locate the physical or process malfunctions that are the root causes of the observed process abnormalities. During the course of diagnostic consultations, the expert system serves to focus the attention of the plant operators and aids in coordinating the diagnostic activity of the plant operators and plant maintenance personnel. The expert system proposes corrective actions upon discovery of a malfunction in the plant. The system architecture is of a modular construction so that it may act as a template for future diagnostic expert systems. This paper also includes a discussion of lessons learned from experience in building the expert system.

Control and primary processing of data from the portable spectrometric system ISOCH-111

The basic moduli and software configuration are examined for the spectrometric system ISOCH-111. Brief summary is made on definition of the basic problems to be resolved in the field of remote sensing. The main principles of operation are discussed for the optoelectron conversion bloc (OEC). Its simplified macromodels are examined in brief as well as the procedures for the solution of the reverse problems in the automatic control of sensitivity and dark current, calibration and data correction. The general configuration of ISOCH-111 is given, its main program moduli are described. In conclusion, the experience of the authors is summarised in the provision of mathematical and system software for the device. The possibility for system expansion is also discussed.

The focusing magnetic resonance system with a new type of supersonic atomic beam source

A focusing magnetic resonance system (MRS) with a new type of supersonic atomic - and molecular - beam source is suggested. The beam sources used in the MRS are discussed and the main operation principles of the suggested supersonic beam source as well as the advantages of this type of source over the rest are shown. An optimization procedure for the magnetic resonance system with the effect of the finite source size taken into account is considered. Numerical results are given and analyzed. The MRS with the new type of beam source possesses higher transmission with low background and is simpler and cheeper in construction as compared to the conventional systems.

A Prototype of Multiprocessor Based Distance Relay

This paper concerns the design and realization of a digital relay for EHV systems. It describes the algorithm which has been used and the main principles of operation. Then it shows how a prototype has been built with four 16-bit microprocessors, to allow the simultaneous real-time computation of three apparent impedances. The hardware and software architecture are described. The paper also presents the results of the tests carried out on the relay: a tripping signal is sent within one period of 50 Hz for all faults (half a period for near-by short-circuits). Furthermore, single-phase tripping, directional discrimination and power-swing detection are provided.

An Electropneumatic Cyclic Loading System

Abstract This paper reviews some of the current systems in use for the application of cyclic loads to soil specimens. Their main features and principles of operation are described. A relatively low-cost electropneumatic system recently developed at the University of California at Berkeley is described in detail. This system provides sinusoidal and other shape load traces using normal compressed air controlled electronically and is an assembly of commercially available components.

Conductivity Crystal Counters

This is a brief review article on conductivity crystal counters in which their main properties and basic principles of operation are described. Their present position in the field of nuclear instrumentation is discussed, it being concluded that there are still many serious problems to be solved before the counters can be of practical use. Some of these problems and the present methods of tackling them are surveyed.