Admissible Deviations Research Articles

A method for organizing the access to the slow-control channels of the ZEUS detector

The slow-control system operation consists in periodic polling of all parameters that need to be controlled and comparing values obtained with admissible deviations from normal values. This is necessary for the safe functioning of the facility and for reliability of the experimental data obtained. For modern experimental setups, when a large number of parameters need to be monitored, the problem of access to the slow-control data becomes complex. In this paper, a method for organizing the access to the slow-control channels is described. The method is based on using two search structures corresponding to the common database for channels and parameters.

Reliable PVD coatings on components: aspects of deposition and characterization for quality management

Although the characteristics of PVD coatings in research and development papers are very promising, in the field of tribology the industrial application of these types of coating has until now been restricted to special market segments. The deposition of hard coatings is state-of-the-art on tools, whereas PVD-coated machine components are quite rare. This is caused by the profile of properties of the coatings, their various surroundings and the demands for application reliability. This last aspect is the main topic of this contribution. Reliability is especially important for machine components, because tools may fail after a relatively short lifetime as compared to machine parts. Besides this, tools and the corresponding production equipment are designed for fast tool replacement, in contrast to other machines which should work without standstill and with a minimum of maintenance. Characteristics of coated systems must be guaranteed in practice, and theory and laboratory experiments have to show what is possible. On the one hand, reproduction of the deposition process must be guaranteed to fulfil application fields with high demands for reliability, while on the other hand, characterization of coated systems must be standardized with admissible deviations which can be communicated between coaters and users. These aspects are important for decisions concerning the use of coating substrate systems in tribology as well as decisions concerning technical functions. The present investigation details the main reasons for deviations in the results of investigations of PVD coatings.

Deposition of PVD Coatings on different geometries and local characterization for reliable properties

AbstractAlthough the characteristics of PVD coatings in research and development papers are very promising, in the field of tribology the industrial application of these coating types is restricted to special market segments up to now: the deposition of hard coatings is state of the art on tools, whereas PVD coated machine components are quite rare.This is caused by the coatings profile of properties, the various surroundings and the demands for application reliability. The last aspect is the main topic of this contribution. Reliability is especially important for machine components, because tools may fail after relative short life time compared to machine parts. Besides this tools and the corresponding production equipment are designed for fast tool replacement in contrast to other machines, which should work without standstill and with a minimum of maintenance.Characteristics of coated systems must be guaranteed in practice theory and laboratory experiments have to show what is possible. On the one hand reproduction of the deposition process must be guaranteed to enter application fields with high demands for reliability, on the other hand characterization of coated systems must be standardized with admissible deviations for communication between coaters and users. These aspects are important for decisions concerning the use of coating substrate systems in tribology besides the topics of technical function.The present investigation shows main reasons for deviations in results of PVD coatings.

Computation of enamel mixtures with complex composition

A computer software for computing complex charge compositions is described. It is shown that when using waste oxide catalysts of petroleum organic synthesis as a raw material, the fraction of oxides introduced by them into the composition of the enamel can reach 95 wt. % at admissible deviations of the computed composition from the specified one.

An analysis of peculiarities of the satellite autonomous navigation in sighting unknown landmarks on the planet surface

An analysis of characteristics of autonomous navigation by using optical sighting of unknown landmarks was carried out for artificial satellites in circular orbits around the Earth with altitudes from 300 to 900 km. It is shown that navigational errors vary approximately in inverse proportion to duration of measurements. Also they decrease with an increasing number of sighted landmarks. The errors poorly depend on the orbit altitude if the duration of measurement for each landmark is chosen in proportion to the orbit altitude, or a maximal zenith angle of sighting the landmark remains constant. Some characteristics of the navigational algorithm are given. Admissible deviations of initial orbital elements from their exact values are investigated. For a properly chosen measurement procedure the algorithm proves to be stable even for rather crudely given initial parameters.

An analysis of characteristics of the satellite autonomous optical navigation system

The autonomous navigation system characteristics are investigated for an artificial satellite around a planet. Navigation is based on the optical scanning of stars near the planet's horizon. The recognition of stars and the measurement of angles of star elevation above the horizon are carried out. The subsequent statistical processing of the measurements allows one to determine the satellite's orbital elements with an accuracy dependent on the measurement accuracy and procedure. The analysis employs an exact numerical algorithm and approximate numerical-analytical technique. The navigational accuracies are studied in relation to independent and correlated measurement errors. Comparison is made for navigational accuracies determined by the above two methods. It shows that the approximate technique allows rather well (with an error less than 10%) to find navigational errors even at a small number (3–6) of times of measurements per revolution. When this number is increased the methodical error of the approximate technique quickly diminishes. The navigational accuracies are obtained for the satellite in an orbit with altitude of 300 to 36,000 km. The navigational algorithm was tested in direct numerical simulation and its convergence bounds were determined. The latter show admissible deviations of initial values in orbital elements from the exact ones. The analysis shows that the algorithm is stable at rather large errors in giving the elements of initial approximation.

Control of defect parameters of 300D90 pumps after overhaul

This article tests ten overhauled 300D90 pumps in order to determine the admissible deviations of pressure heads and efficiency, and in order to formulate general technical specifications (TS) for the overhaul of D-type pumps. The operation and maintenance of 300D90 pumps under Siberian conditions showed that the inner surfaces of the housing components of the pumps have to be restored by surfacing and the rotors and slot seals have to be replaced by those reconditioned in the repair works. The average head of the overhauled pump was 26.9 m and the average efficiency was 81.3%. A comparison of the values obtained with the specifications of new pumps showed that the overhauled pumps have a head 1.3 times higher and an efficiency 9.1% lower than those specified for new pumps. It is determined that the deviation of the parameters of the overhauled pumps from the rated parameters can be reduced by improving the repair quality.

On the approximations and bifurcations of a dynamic system: PMM vol. 35, no. 5, 1971, pp. 780–796

By means of an example of a classical problem in flight dynamics we examine the influence of approximation on the structure of the partitioning of the phase space and of the parameter space of a dynamic system. For a qualitative investigation of dynamic systems we can use the transition from the original model to a simplified or piece-wise integrable one, by approximating the characteristics in the equations of motion. Here arises the important question of the admissible deviations of the approximating functions from the real characteristics for the preservation of the necessary closeness between the original and the approximating system. The concept of necessary closeness is not unique and is determined by the aims of the investigation. For example, it can be understood as the requirement of retaining for the approximating system the same phase space and parameter space partitioning structure as for the original system [1]. In a general formulation the problem reduces to the question of preserving or losing bifurcations during the transition to the approximating system. The difficulties arisising here are connected with the fact that not all the bifurcations may be kept track of by regular methods, and furthermore, for “fused” approximating systems (piecewise-analytic ones) there may arise new types of bifurcations for which there is no complete classification as yet. Therefore, a comparative analysis of actual dynamic systems under different approximations is of interest. Below we carry out such an analysis on the basis of an example of a classical problem in flight dynamics [2–9]. The choice of this problem was dictated by the fact that in the original system a wide collection of bifurcations is possible (all types of bifurcations of the first degree of structural instability are realized) and by the fact that we have succeeded in establishing strictly the parameter space partitioning structure both for the original system (which had not been done to this time) as well as for the approximating systems. Here differences arise in the partitioning structure of the parameter space and of the phase space, permitting us to evaluate the influence of the approximations on the partitioning structure and to uncover, in particular, the important role played by the “saddle index” [10]. The retention of a quantitative closeness of the characteristics did not prove to be obligatory for the preservation of the qualitative partitioning structure of the system's phase and parameter spaces. The use of the saddle index in the qualitative investigation of “fu/.sed” systems is based on the possibility of carrying over the assertions concerning the stability conditions for a separatrix loop and the conditions for the birth of limit cycles from it, to nonanatytic systems, preserving the loop in whose composition the analytic saddle occurs. Theorems 44 – 49 in [10], with appropriate changes of formulations, remain valid for the systems mentioned because the method by which they were established carry over to these systems.

The Effect of Distortion of Subcavitating Foil Contours on Cavitation-Inception Velocity

The purpose of this paper is to investigate the theoretical effect of distortions on sub-cavitating foil sections in regard to cavitation-inception velocities. The study is intended to give some prediction as to type and size of distortions that may be tolerated in foil construction. It is natural to expect errors in foil shape to occur as a result of inaccurate construction or damage. It is therefore the intention of this paper to provide estimates of admissible deviations from the intended foil geometry in order that cavitation may be prevented or at least anticipated.