Search results for "Forensic engineering"
showing 10 items of 116 documents
Laser-air hybrid ultrasonic technique for dynamic railroad inspection applications
2005
The Laser-Air Hybrid Ultrasonic Technique (LAHUT) combines laser generation with air-coupled detection of ultrasound. The technique is non-contact and has the characteristic of operating from remote distances. Acoustic wave laser-generation apparatus can be metres away from the interrogated surface, while air-coupled detection stand-off can be on the order of several centimetres. The technique has the unique capability of interrogating structural materials in their true industrial environment. Dynamic tests are performed on parts with complex geometry, limited accessibility and curved surfaces. Also, dark and rough finish surfaces, which significantly reduce the efficiency of optical detect…
Fatigue life prediction under wide band random loading
2004
In this paper, a method for the high-cycle fatigue life prediction of components subjected to gaussian, stationary, wide band random loading is presented. It allows the user to evaluate the fatigue life of components subjected to uniaxial stress states directly from the stress power spectral density (PSD), avoiding onerous simulations in time domain. The proposed method can be applied to random stress processes having PSD of any shape, and the fatigue life predictions obtained are more accurate than that provided by most of the frequency domain techniques proposed in literature.
A Simple Model for the Axial Thrust in V-Belt Drives
1996
Simple formulas can relate axial thrust and torque of rubber V-belt drives, taking into consideration the radial penetration of the belt.
Solving underwater crimes: development of latent prints made on submerged objects.
2013
Underwater crime scenes always present a challenge for forensic researchers, as the destructive effect of water considerably complicates the chances of recovering material of evidential value. The aim of this study is to tackle the problem of developing marks that have been left on submerged objects. Fingermark deposition was randomly made on two surfaces - glass and plastic whilst the material was submerged under tap water and then left for one to fifteen days before drying and development. For their later development, various reagents - Black Powder, Silver Metallic Powder, Fluorescent Powder, Sudan Black (powder and solution) and Small Particle Reagent - were used and the effectiveness o…
Highlighting inconsistencies regarding metal biosorption.
2015
Thousands of articles have been devoted to examine different types of biosorbents and their use in cleaning polluted waters. An important objective of some studies has been the identification of the biosorption mechanisms. This type of investigation is not always performed, as it can only be done if scientists are aware of all mechanisms that, at least theoretically, control the removal of the target substances. Mistakes are often made, even in highly cited review articles, where biosorption mechanisms are named and/or grouped. The aim of this article is to highlight errors and inaccuracies as well as to discuss different classification systems of the biosorption mechanisms. This article se…
In-situ NDT testing procedure as an integral part of failure analysis of historical masonry arch bridges
2015
Abstract A nineteenth-century masonry arch bridge was analyzed as an illustrative example to explain the role of in-situ test campaigns in failure analysis and retrofit design. Test results were studied to find out the advantages of each technique, with the aim of proposing an optimized in-situ testing procedure. Standard static penetrometer, flat jack, thermographic and georadar in-situ tests were conducted. Traffic effects were analyzed by means of vibrational tests. The experimental analysis performed to investigate damage on the bridge structures shows the degree of reliability offered by each technique in evaluating specific information and reproducing the global behavior of the struct…
Tool Wear and Damage
2008
This chapter provides comprehensive knowledge regarding tool wear mechanisms and characterizes their physical fundamentals. Adhesion, abrasion, diffusion and oxidation are selected as predominant mechanisms controlling tool wear, depending on the mechanical and thermal conditions at the rake and flank faces. The analytical models describing the wear rate and volumetric material loss for different wear mechanisms are provided. The tool wear indicators related to crater, flank and notch wear specified in ISO 3685 are presented for both flat-faced and grooved tools. Tool life is defined and corresponding models, including the influence of cutting speed, feed and the depth of cut, are derived. …
On the Influence of the Radius Between Face and Flank on the Tool Life of Sintered Carbides
1985
Experimental investigations carried out by the authors in interrupted cutting, show that if the cutting edge survives to few impacts, then fracture will take place to very high number of impacts. Early fractures can be explained by assuming the presence of microscopic defects on the tool edge; a longer life can be referred to an increase tool strengthness due to rounding of the edge as a consequence of the wear process. In order to study the effects of the rounding of the edge, experimental tests have been carried out on several inserts of sintered carbides with different values of the radius of the edge between face and flank obtained by a tumbling process. The results show that the greate…
Time Dependent Deterioration of the X-Ray Dental Diagnostic Equipment
2013
Modern dental X-ray examinations are essential for diagnosis. The goal of this paper is to demonstrate time dependent behavior of dose providing parameters, which help to determine equipment’s age effects on the x-ray machine parameters. Also the comparisons between two different dental X-ray generator equipment types half-period and high frequency was made.