scholarly journals THE PARASITE PHENOMENON IN A TCAVE CANAL

2011 ◽  
Vol 1 (5) ◽  
pp. 6
Author(s):  
J. Kravtchenko ◽  
L. Santon
Keyword(s):  
Longitudinal Axis ◽  
Recording Apparatus ◽  
The Subject ◽  
Wave Profiles ◽  
Wave Filters ◽  
Wave Recording

A detailed study of wave profiles undertaken by our laboratory and making use of a wave recording apparatus, which is the subject of another paper, has drawn our attention to a parasite phenomenon. In certain conditions this phenomenon has a period twice that of the principal movement. The phenomenon appears only over a certain range of periods and has been shown to be the result of a transversal clapotis. The appearance of a transversal clapotis in wave canals is not rare and in practice it is eliminated by placing vertical guides parallel to the longitudinal axis of the canal. We have succeeded in eliminating the transversal clapotis reasonably well, by the use of wave filters. But a progressive phenomenon, with the period of the clapotis, has remained and it has been possible to analyse it.

Problems of metrologic assurance with wave recording apparatus

1990 ◽  
Vol 33 (11) ◽  
pp. 1113-1117
Author(s):  
A. P. Aleksandrov ◽  
�. S. Vaindruk ◽  
G. Yu. Narodnitskii
Keyword(s):  
Recording Apparatus ◽  
Wave Recording

Rotating Aerofoils and Flaps

1963 ◽  
Vol 67 (625) ◽  
pp. 47-63 ◽  
Author(s):  
S. Neumark
Keyword(s):  
Longitudinal Axis ◽  
Short Review ◽  
Control Device ◽  
Theoretical Research ◽  
Circular Cylinders ◽  
Small Scale ◽  
Axis Of Rotation ◽  
Aerodynamic Properties ◽  
Magnus Effect ◽  
The Subject

Some aerodynamic properties of auto-rotating or forcibly rotated cylinders and aerofoils were investigated even prior to the beginning of aviation and, somewhat surprisingly, it was Maxwell who wrote the earliest (1853) known paper on the subject. That entirely non-mathematical paper tried to explain the curious behaviour of an oblong card which, left to fall freely in the air, started immediately to rotate about its longitudinal axis while deviating from the vertical in the horizontal direction perpendicular to the axis of rotation. Steady “terminal” conditions are soon reached in which speed, rate of rotation, and path angle, are all constant. This simple experiment revealed at once two important properties of an “aerofoil of large aspect ratio“: (1) ability to autorotate, and (2) ability, when rotating in an air stream, to create an asymmetrical pressure distribution resulting in a force normal to both axis of rotation and mainstream velocity. About the same time, the famous “Magnus effect” on rotating circular cylinders was discovered, but it was not before the Kutta-Joukowski theory of aerodynamic lift appeared some 50 years later that a more general understanding of the “lift through circulation” principle became possible. Magnus effect found important applications in ballistics, and one serious (although not economically successful) attempt was made to apply it in maritime navigation (Flettner's rotorship). As to the use of aerofoils rotating about a horizontal transverse axis for generating lift in aircraft, very little indeed has been done apart from some early publications. The concept of a wing with rotating flap as a lift-augmenting or control device arose from suggestions by Riabouchinsky and Chappedelaine, and there were some early French and German patents based on this concept. However, the matter was soon abandoned. It was taken up again during the last war in Germany, where some interesting experimental and theoretical research was done on a small scale. The subject has apparently never attracted any attention in Britain until 1957 when a short review of the existing information was given by Crabtree. This was followed by the lecturer's own effort which concentrated on the relevant mathematical theory.

scholarly journals Narrow-band filter for satellite communication systems

2021 ◽  
Vol 10 (3) ◽  
pp. 198
Author(s):  
Alexander Vladimirovich Strizhachenko ◽  
Sergey Nikolayevich Shulga
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Narrow Band ◽  
Longitudinal Axis ◽  
Center Frequency ◽  
Narrow Bandwidth ◽  
Band Filter ◽  
Narrow Band Filter ◽  
Paper Filter ◽  
The Subject

Design narrow-band compact filters, based on high-quality waveguide-dielectric resonators with anisotropic materials is the subject of this paper. Filter represents a segment of a rectangular waveguide rotated around the longitudinal axis of the waveguide 90 degrees and containing one or more dielectric inserts that completely fill the resonator along the narrow wall of the waveguide and partially along the wide one. A distinctive feature of the proposed filter is higher slope steepness of the amplitude-frequency characteristic, and high manufacturability in the centimeter range. The designed narrow-band filter satisfies contradictory requirements: it combines narrow bandwidth (≈ 0.1% of center frequency <em>f</em><sub>0</sub>) with low passband insertion loss (≤ 1 dB).

scholarly journals The dissipation of energy by electric currents induced in an iron cylinder when rotated in a magnetic field

1902 ◽  
Vol 70 (459-466) ◽  
pp. 359-374
Keyword(s):  
Magnetic Field ◽  
Electromotive Force ◽  
Relative Phase ◽  
Longitudinal Axis ◽  
Electric Currents ◽  
King's College ◽  
The Subject ◽  
Energy Dissipated ◽  
Present Section ◽  
Assistant Lecturer

The effect which induced electric currents have upon the distribution of magnetism in an iron cylinder, when rotated in a magnetic field, has formed the subject of a communication, and it is the object of this paper to deal with the energy dissipated by these electric currents. A comparison will be made between the results of experiment and theory. In connection with the latter, I have to thank J. B Dale, Esq., M. A., Assistant Lecturer in Mathematics, King's College, London, for a contribution which at his wish I append to this paper. The cylinder used in the experiments has diameter and length each 10 inches (25·4 cm.). Since the previous experiments were made additional holes have been drilled in a plane containing the longitudinal axis of the cylinder, and its present section is shown m fig. 1. Insulated copper conductors have been threaded through these holes, and inclose areas indicated by the thick lines in fig. 1. The coils are numbered 1, 2', and 4, and inclose areas of 25·8, 232, and 654 sq. cm. respectively. As in the previous experiments, the electromotive force in each coil has been calculated from the observed deflection of the needle of a D’Arsonval galvanometer placed in each circuit. The deflections were observed simultaneously, thus enabling the relative phase-displacements to be determined.

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.

Effects of Hyperoxia on Lung Utrastructure

1970 ◽  
Vol 28 ◽  
pp. 26-27
Author(s):  
Gladys Harrison
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Light Microscopy ◽  
Oxygen Effects ◽  
Age Dependent ◽  
The Central Nervous System ◽  
The Subject ◽  
Space Age ◽  
Alveolar Septa ◽  
Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

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