In pipelines for transporting oil and gas, multiple cracks often exist in weld joints. The interaction among the should be considered as it directly affects life span of pipeline structures. current investigation, based on fluid–solid magnetic coupling model, virtual crack-closure technique (VCCT) is applied to systematically study multi-crack dynamic effect welds during crack propagation proce...

S OF RECENT SCIENTIFIC PUBLICATIONS OF THE N.V. PHll..IPS' GLOEU,AMPENF ABRIEKEN Reprints of these papers not marked with an asterisk can be obtained free of charge upon application to the Administration of the Research Laboratory, Kastanjelaan, Eindhoven, Netherlands. 1880:' J. ter Berg and G. J. van Wijnen: The porosity of welds (Welding J. 28, 269 S-271 S, 1949, No. ,6). A study of external ...

Laser-enhanced gas metal arc welding (GMAW) is an innovative process recently proposed and developed at the University of Kentucky (Refs. 1–3), shown in Fig. 1. It adds a relatively low-power laser to conventional GMAW, and the objective is to provide an auxiliary force to help detach the droplet at a desired diameter with a desired welding current. In laserenhanced GMAW, the droplet size is a ...

Welded constructions play a vital role in power plant components. Power industry utilization of radiography for integrity of welds is a common practice in the vessel manufacturing industry. Recent developments in the field of ultrasonic utilize Time of Flight Diffraction Technique (ToFD) for evaluation of welds with respect to Engineering Critical Assessment approach for evaluation of welds. Re...

We present a methodology for automatic corrosion detection in digital images of carbon steel storage tanks and pipelines from a petroleum refinery. The database consists of optical digital images taken from equipments exposed to marine atmosphere during their operational life. This new approach focuses on color and texture descriptors to accomplish corroded and noncorroded surface area discrimi...

Local strength of friction stir (FS) welds and FS processed aluminium alloys in heat treatable aluminium alloys is dominated by precipitation hardening. Strengthening due to stored dislocations is generally limited to 40MPa, and grain size strengthening is generally less than 10MPa. Local crystallographic texture can cause yield strength variation on the order of 5%. Published models for streng...

The goal of the work is the research of formation mechanism of the spot resistance welds in the case of copper wires with nickel and tin coatings. The existing approaches for investigation of the formation mechanisms of welds of wires with and without coatings are analysed. A new approach for modeling of welding joint formation is offered. The analog model of the heat input during resistance we...

Ultrasonic phased arrays are a new technology that offers considerable potential for inspecting construction welds. Using electronic control of the beam, phased arrays can scan, sweep, steer and focus the ultrasound. Since welds typically produce defects of known character and orientation, phased arrays can be programmed to optimize weld inspections. These inspections include standard ASME-type...

For an arbitrary (3,L) QC-LDPC code with a girth of twelve, a tight lower bound of the consecutive lengths is proposed. For an arbitrary length above the bound the resultant code necessarily has a girth of twelve, and for the length meeting the bound, the corresponding code inevitably has a girth smaller than twelve. The conclusion can play an important role in the proofs of the existence of la...

Graph G is the square of graph H if two vertices x, y have an edge in G if and only if x, y are of distance at most two in H . Given H it is easy to compute its square H, however Motwani and Sudan proved that it is NP-complete to determine if a given graph G is the square of some graph H (of girth 3). In this paper we consider the characterization and recognition problems of graphs that are squ...