Etika : Bertanya dan mencari jawaban

Buku ini menerangkan secara mudah bagaimana menemukan makna hidup yang baik. Persoalan etis tidak hanya memusingkan orang yang terpaksa memecahkan masalah besar. Dalam kehidupan sehari-hari kita semua menghadapi pertanyaan bagaimana cara memperlakukan orang lain. Pengarang mengemukakan banyak contoh seperti sejarah dari bangsa-bangsa di dunia untuk menjelaskan pokok persoalan yang harus dihadapi jika harus mengambil keputusan

Letter to Dr. Gideonse from the Chairman of the Work Camp Committee

Letter inviting Dr. Gideonse to a meeting on April 23, 1941 to discuss the upcoming work camp. April 14, 1941

Book Review (First You Shave Your Head)

Abstract not availabl

Impact-echo: Experimental and numerical study of acoustic wave propagation

Impact echo is an acoustic NDT method successfully used for the investigation of concrete structures. For the interpretation of the measurements a detailed investigation of the acoustic wave propagation is highly relevant. This paper describes useful techniques for that purpose. By using a scanning laservibrometer it is possible to obtain a visualization of sound waves propagating along the surface of a concrete specimen. The interaction of the sound waves with tendon ducts as well as their behaviour when reaching the backwall of the specimen are investigated. Impact-echo measurements in transmission arrangement, in which the transducer is placed on the opposite side to the excitation, enable further investigation of the so-called geometry effects, which disturb the signals obtained from structures with limited dimensions. In order to visualize the surface wave propagation an arrangement showing the instantaneous wave field on all planes of the specimen in phase with the excitation is used. Time slices then show the instantaneous wave field for all points on the surface of the specimen. The experimental results are compared with numerical simulations

Demonstration of measurements using impulse-radar, ultrasonic echo and impact-echo on a pre-stressed concrete railway bridge in Duisburg / Germany : Sustainable Bridges Background document SB 3.17

Non-destructive test- (NDT-) methods are not yet commonly used for inspection of concrete structures. The automated application of enhanced methods as impulse radar, ultra sonic echo and impact-echo during inspection and condition assessment of existing prestressed concrete bridge structures is tested in this deliverable. These methods were used at a railway bridge in Duisburg/Germany to determine thickness of structures and to localize reinforcementand tendon ducts. The automated tests were performed in October 2005. As results, the tendon ducts in the area of the bridge deck and the web were located using impulse-radar and ultrasonic echo. Advantage of echo-measurement set-up is the accessibility only from one side. The accuracy of the determination of the thickness of the structures or the concrete cover of rebar and tendons depends on the calculation of the wave velocities. Structural elements of known thickness or the radar CMP (Common Mid Point) measurements might be used as references for calibration of the wave velocities. Accurate information about the localisation of tendons was not achieved with impact-echo at this bridge. But investigations have shown that geometry-effects can be reduced by measurements in transmission arrangement.EC Sixth Framework ProgramSustainable Bridges – Assessment for Future Traffic Demands and Longer LivesTIP3-CT-2003-001653</p

Experimental study of elastic waves in concrete for NDE in civil engineering

Laser vibrometric contactless sound field measurements it a concrete test block are presented. Both excitation by an ultrasonic probe and by an impactor were used. The wave modes can be identified by their geometric wave forms and propagation velocities. Additionally, numerical simulation of the experimental situation is used to support this interpretation. Possible applications of the presented technique are discussed

Fundamental techniguies in veterinary surgery

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