Optimization of Rotor Critical Speeds by Change of Features of Machine’s Bearings

2004 ◽  
Author(s):  
Jozef Rybczynski
Keyword(s):  
Critical Speeds ◽  
Mean Temperature ◽  
The Subject ◽  
Operation Parameters ◽  
Turbo Compressor

The subject of this article is an analysis of the influence of changes of certain construction and operation parameters of slide bearings on the critical speeds and corresponding forms of vibrations of rotors supported in such bearings. An exemplary analysis has been made for a typical, average sized turbo-compressor train consisting of three rotors. It has been found that critical speeds of a rotor are most sensitive to the bearings clearance; less sensitive to the bearings length, and least sensitive to the oil mean temperature. Found relations permit to avoid an accidental search for a way to change the rotor critical speeds if there is such a necessity and when it is impossible to change the geometry of the rotor itself. The results of the analysis allow optimization of the process of detuning the machine from resonance.

V. Some observations on the heat of wells and springs in the island of Jamaica, and on the temperature of the Earth below the surface in different climates

1788 ◽  
Vol 78 ◽  
pp. 53-65
Keyword(s):  
The Earth ◽  
Mean Temperature ◽  
The Subject ◽  
The Mean ◽  
Different Climates

The Following observation on the heat of springs and wells, and their application towards determining the mean temperature of the earth in the different climates, were suggested by you in some observation on the subject, previous to my going to Jamaica in 1780.

scholarly journals Multiple-criteria decision analysis of the transformable low-rise building technological construction process

2018 ◽  
Vol 193 ◽  
pp. 03042 ◽  
Author(s):  
Elena Korol ◽  
Alexander Pleshivcev
Keyword(s):  
Construction Industry ◽  
Sandwich Panel ◽  
Indicator Function ◽  
Multiple Criteria ◽  
Construction Process ◽  
Technological Processes ◽  
Overground Part ◽  
The Subject ◽  
Operation Parameters ◽  
The Relationship

One of the promising areas of improving the constructive and technological solutions of low-rise buildings is the fast-erecting systems. Increase of efficiency of the erection process of these systems can be implemented on the basis of the results of a multiple-criteria analysis of the organizational and technological processes by decomposing it into separate technological processes and operations and assessing their impact on the overall building erection process. The structure of a multiple-criteria model includes such indexes as the duration of separate technological processes and the operation of the overground part in the building erection. The subject of the study – technological operation parameters during the installation process of the transformable low-rise buildings with sandwich panel walls. Based on selection, classification, and systematization of the factors determining the resultant indicators, the relationship between the effective indicator (function) and the factors (arguments) was studied and their forms of dependence were determined based on the linkage modeling. The calculation of the influence of various factors and their assessment on the change in value of the effective indicator was performed. The selected factors include several parameters in the form of technological operations, which are expressed in hours. The simulation of technological process using a multiple-criteria model allows determining the efficiency reserves of the developed technology. Its application in installation control processes could help the construction industry with transformable low-rise building erection.

The Turbo - Compressor and the Supercharging of Aero Engines

1931 ◽  
Vol 35 (251) ◽  
pp. 1047-1074
Author(s):  
F/O. F. Whittle
Keyword(s):  
General Problem ◽  
Aircraft Engines ◽  
General State ◽  
High Altitudes ◽  
Brief Treatment ◽  
The Subject ◽  
Turbo Compressor ◽  
Aero Engines

If the amount of printed matter published on a technical subject is any guide to the general state of knowledge on that subject, then neither the turbo-compressor nor the general problem of the supercharging of aircraft engines can be very well understood at present, much less the combination of the two. Apart from the brief treatment accorded to the behaviour of engines at high altitudes, and supercharging in the well-known text-books on engines, the only printed matter available on the subject is contained in papers published in technical journals (so far as one knows), viz.:—“ Supercharged Aero Engines,” R. F. R. Pierce, the Journal of October, 1926.

scholarly journals On solar changes of temperature and variations in rainfall in the region surrounding the Indian Ocean

1901 ◽  
Vol 67 (435-441) ◽  
pp. 409-431 ◽  
Keyword(s):  
Indian Ocean ◽  
The Sun ◽  
Abnormal Behaviour ◽  
Sunspot Maximum ◽  
Sunspot Minimum ◽  
Mean Temperature ◽  
The Indian Ocean ◽  
The Subject ◽  
The Mean

The fact that the abnormal behaviour of the widened lines in the spectra of sunspots since 1894 had been accompanied by irregularities in the rainfall of India suggested the study and correlation of various series of facts which might be expected to throw light upon the subject. The conclusions already arrived at from bringing together the results of several investigations undertaken with this view may be stated as follows:— (1.) It has been found, from a discussion of the chemical origin of lines most widened in sunspots at maxima and minima periods, that there is a considerable rise above the mean temperature of the sun around the years of sunspot maximum and a considerable fall around the years of sunspot minimum.

scholarly journals Durability Control of Brickwork's Material Including Operation Parameters of the Building Enclosure

2021 ◽  
Vol 8 (6) ◽  
pp. 871-880
Author(s):  
Dmitry Zheldakov ◽  
Radik Mustafin ◽  
Vladimir Kozlov ◽  
Askar Gaysin ◽  
Dmitriy Sinitsin ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Chemical Processes ◽  
Laboratory Research ◽  
Material Degradation ◽  
Chemical Corrosion ◽  
Building Enclosure ◽  
Building Enclosures ◽  
The Subject ◽  
Operation Parameters ◽  
Material Durability

This paper aims to develop a method to determine material durability based on physicochemical laws that describe chemical corrosion in building enclosures. The subject of this research is studying the chemical corrosion in the material in building constructions. The object of this research is the material of building ceramics. Methods that the authors used for reaching this goal include developing a multi-staged process of material degradation of building ceramics, conduction of thermodynamic calculations, and conducting laboratory research on process kinetics. The results of kinetic researches are generalized based on a developed mathematical model. This comprehensive approach to solving the goal task allowed obtaining the following results: research methods of chemical processes in brick material and its plaster on humidification were developed. A mathematical model for evaluating material degradation in time with the changing climatic influence on enclosure was developed.

Words

PMLA ◽  
1935 ◽  
Vol 50 (4) ◽  
pp. 1320-1327
Author(s):  
Colbert Searles
Keyword(s):  
Subject Matter ◽  
Assistant Professor ◽  
The Subject

THE germ of that which follows came into being many years ago in the days of my youth as a university instructor and assistant professor. It was generated by the then quite outspoken attitude of colleagues in the “exact sciences”; the sciences of which the subject-matter can be exactly weighed and measured and the force of its movements mathematically demonstrated. They assured us that the study of languages and literature had little or nothing scientific about it because: “It had no domain of concrete fact in which to work.” Ergo, the scientific spirit was theirs by a stroke of “efficacious grace” as it were. Ours was at best only a kind of “sufficient grace,” pleasant and even necessary to have, but which could, by no means ensure a reception among the elected.

Artificial satellite orbit computations

1966 ◽  
Vol 25 ◽  
pp. 363-371
Author(s):  
P. Sconzo
Keyword(s):  
Artificial Satellite ◽  
Satellite Orbit ◽  
Artificial Satellites ◽  
Orbital Elements ◽  
Differential Correction ◽  
Gravitational Effects ◽  
Short Intervals ◽  
The Subject ◽  
Introductory Discussion ◽  
Orbit Computation

In this paper an orbit computation program for artificial satellites is presented. This program is operational and it has already been used to compute the orbits of several satellites.After an introductory discussion on the subject of artificial satellite orbit computations, the features of this program are thoroughly explained. In order to achieve the representation of the orbital elements over short intervals of time a drag-free perturbation theory coupled with a differential correction procedure is used, while the long range behavior is obtained empirically. The empirical treatment of the non-gravitational effects upon the satellite motion seems to be very satisfactory. Numerical analysis procedures supporting this treatment and experience gained in using our program are also objects of discussion.

C. Wire Cabling for Telescope Systems

1966 ◽  
Vol 27 ◽  
pp. 159-161
Keyword(s):  
The Subject ◽  
Data Multiplexing

Rule: I'd like at this point to bring up the subject of cables and wireways around the telescope. We've touched upon this twice during previous sessions: the cable wrap up problem, the communications problem, and data multiplexing problem. I think we'll ask Bill Baustian if he will give us a brief run down on what the electrical run problems are, besides doubling the system every year.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Direct Observations of the Epitaxial Growth of Sputtered Ag on Si

1973 ◽  
Vol 31 ◽  
pp. 122-123
Author(s):  
J. S. Maa ◽  
Thos. E. Hutchinson
Keyword(s):  
Epitaxial Growth ◽  
Film Growth ◽  
Ion Beam ◽  
Ion Beam Sputtering ◽  
Microscopy Technique ◽  
Direct Observations ◽  
In Situ Electron Microscopy ◽  
Beam Sputtering ◽  
The Subject

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.

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