Wear and T.E.M. Studies of P.E.C.V.D. Diamond-like-Carbon Films

Diamond-like-carbon (D.L.C.) films are characterized by a low friction coefficient, a high wear resistance and a high corrosion resistance. D.L.C. films can be obtained by P.V.D., C.V.D. and duplex techniques with solid or gaseous precursors. Depending on the processing, hydrogen concentration ranges between 0 and 60%

In this study, hydrogenated D.L.C. has been deposited with a radio frequency system (13.56 MHz) onto a steel substrate. Wear was studied by pin-on-disc testing at room temperature with an alumina counterpart. Interrupted tests were carried out to go into wear mechanisms. Debris were collected after various given sliding times for transmission electron microscopy (T.E.M.) in addition to scanning electron microscopy (S.E.M.) applied to the wear tracks.     

Measurement techniques for UMTS signals radiated by radio base stations

In the most European countries radio coverage for the third radio mobile generation. i.e, the UMTS (Universal Mobile Telecommunications System), will soon be started. In the past few years, national laws specifying limits on exposure to electromagnetic fields have drawn much attention on electromagnetic test bed and measurement procedures for radio mobile equipment/systems. An overview is given of the UMTS system, showing the main characteristics of the radio access network UTRAN (UMTS Terrestrial Radio Access Network). An analysis is also provided as to the measurement techniques and related instrumentation for the electric field intensity radiated by a UMTS radio station.     

Tissue-characterization of the prostate using radio frequency ultrasonic signals

In this paper, we will present a complete method and system for the detection of prostatic carcinoma, providing color-coded images of the estimated probability of malignancy by processing radio-frequency ultrasonic echo signals. For this, a hardware setup based on a conventional diagnostic sonograph was realized. The image-processing software works on ultrasound images automatically segmented into regions of about 3x3.5 mm. System-dependent effects, as well as tissue attenuation, were measured and compensated for. Tissue-characterisation parameters, which have been used successfully by other authors, were calculated for each segment. To demonstrate the methods of selection of relevant parameters and comparison of different classifiers, a first clinical study using data of 33 patients with local prostatic carcinoma was performed. For these patients, location and extent of the carcinoma were known from histological findings after radical prostatectomy. Classifiers investigated during the study were: the linear and quadratic Bayes classifier, a nearest neighbor classifier, and several classifiers based on Kohonen-maps. The best classifier was used to calculate color-coded result images. Applying a threshold of 50% to the estimated probability of malignancy, produced the encouraging results of 82 and 88% for sensitivity and specificity, respectively.     

Measuring cosmic ray radio signals at the Pierre Auger Observatory

The recent results of the LOPES and CODALEMA experiments open the door to a renewal of the radio technique for cosmic ray induced shower measurements. The demonstration has been done of its potential and performances at energies below 10¹⁸ eV, this upper limit being due to the small scale of the current experiments. A natural stage toward the improvement of the method is thus to install radio detectors in association with a large cosmic ray detector such as Auger. Besides surface and fluorescence detection, radio detection could be an alternative method, providing a complementary information. The Pierre Auger Collaboration has thus engaged a R&D effort which will lead to the installation of a radio engineering array covering 20 km² on its southern site. Outline of the technique, results of the first phase of the tests and current plans for the future engineering array will be presented.     

D. E. Hughes Self-induction and the Skin-Effect

A commonly-encountered circumstance of technical progress is the existence of a phase during which a formerly neglected observation attracts widespread attention. This may follow on some unrelated event such as an unanticipated need or a dispute, in which material previously obscure suddenly rises in importance. The skin-effect¹ in wires was such a dormant issue before 1886. Its existence had been realised by theorists such as Heaviside, Lamb and Maxwell and no doubt, if left to itself, it would in time have found its natural place in the theoretical architecture then being created. However, a Presidential Address made in January, 1886, to the Society of Telegraph Engineers and Electricians by David Edward Hughes gave a sudden impetus to the study of self-inductive phenomena. Hughes's results appeared as a weighty and public challenge to theoretical expectations and provoked an extensive and year-long period of criticism and discussion, during which the skin-effect emerged as a central issue. His experiments and interpretations were to a large, extent discredited and have come to be regarded rather as a scientific solecism, but nevertheless the effects of the debate on the practical applications of electromagnetism were very far-reaching. The skin-effect remained a paradigmatic case in electromagnetic theory, but also the obvious practical implications revealed in the debate imposed upon electrical engineers the need to revise their conceptualisation of the subject and to reevaluate the status of mathematical theory in practical matters. This paper describes the events, mainly of the year 1886, which initiated the tortuous promotion of self-induction to the status of a governing principle in electrical communications.     

Colloque International RILEM-A.B.E.M.

Sans résumé

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RILEM-A.B.E.M. International Symposium Brussels, August 30th–September 1st 1967

     

A modification of the iteration method of M. E. Shvets

A modification of the well-known method of M. E. Shvets [1, 2] is proposed, whereupon the method becomes iterational — interpolational.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 19, No. 1, pp. 84–93, July, 1970.     

Evaluating the sensitivity of a correlation method of measurement of fluctuating radio signals

Correlation techniques are used to measure weak fluctuating signals encountered in various physical problems. A new correlation meter is proposed which operates using higher harmonics of a heterodyne signal. The sensitivity of the proposed device is evaluated, the measurement error caused by the first approximation is estimated, and the influence of nonlinear distortions of the analyzed signals is studied.     

Inelastic dynamic response of R.C. beam column joints by using B.E.M.

A BEM formulation to obtain the inelastic response of R.C. Beam-Column joints subjected to sinusoidal loading along the boundary is presented. The equations of motion are written along with kinematical and constitutive equations. The dynamic reciprocal theorem is presented and the temporal dependence is removed by assuming steady state response.