Fracture mechanics defect assessment diagram on pipe from steel P264GH with a notch

The design for a pipeline component is considered a tough challenge once defects in the base material develop. To address this issue, we present a gouge defect located in a pipe submitted to internal pressure. This problem is often encountered in the field of pipeline network and boiler components because of structural imperfection. To simulate the activity of such pressurized pipeline, a longitudinal cylindrical shell under pressure from a material of steel P264GH were involved in the research. Secondly, by this paper we propose a safety methodology to detect the boundary of failure assessment diagram (FAD), as a new solution to predict the service life of pipeline products. The methodology is connected to the modified FAD approach, whereas the specific parameters were settled using the Volumetric Method calculation, based on the notch Stress Intensity Factor, determined in the elasto-plastic field. This new modified FAD methodology entails an accurate solution, suitable to be used as expert tool for the assessment of workability and reliability of pipes network, in the case of corrosion defects presence.     

Using geometrical routing for overlay networking in MMOGs

At a first glance, transmitting update information to a geographic region in the virtual space seems to be an attractive primitive in Massively Multiplayer Online Gaming (MMOG) applications where players are constantly moving and need to send updates to their neighbors who are in the same region of the virtual space. The system would become more scalable if entities did not need to keep track of each other or send messages directly to one another. Rather, an entity could just send a message to a specific region in the virtual space (its area of effect), as opposed to sending packets to specific IP addresses, significantly reducing tracking and routing overhead. Fundamentally speaking, update message exchange is mostly based on users’ visibility range, which is mainly affected by proximity; i.e., avatars are interested in nodes within a specific distance around them. Therefore MMOG applications require a routing scheme that can deliver messages to specified locations in the virtual space. Such location based routing motivates the use of geographical routing, which has been introduced and successfully used in the context of wireless networks; however, in its current form it is not well suited for MMOGs which run on wired networks. In this article, we propose a scalable MMOG networking architecture based on hierarchical multi-grid geographical routing that is well suited for MMOG networks. We present our concept and design of hierarchical geometrical routing based on locality sensitive hashing, demonstrate its performance, and discuss both the strengths and shortcomings of our approach.     

Explicit and implicit animation with fuzzy constraints of a versatile multi‐body system for virtual hand surgery

This work is designed to control the movement of hand structural agents under external action, using the implicit animation driven by explicit animation technique (AI‐CAE technique). Starting from the configuration of a hand at rest obtained by a 3D scanner and after meshing of the structural agents, we seek the configuration of the rigid agents under orthopaedic surgeon external action and interacting reliance of deformable and rigid agents. We have developed a model and software tools to answer this interactive application with adaptive execution. The first contribution comes from notations and definition of a versatile multi‐body system dedicated to the explicit and implicit animation. The second contribution comes from the implicit animation driven by explicit animation itself, and from its ability to mimic the role of cartilages and ligaments. The resulting technique is applied to the bone structure consistency of a specific human hand in the context of virtual hand orthopaedic surgery. The versatile specific multi‐body is made up of hierarchical interacting agents conceivable as a construction set of rigid bones with cartilages–ligaments and underlying links. The explicit animation produces a desired configuration from geometric command parameters of torsion, flexion, pivot and axis shifting, given in a scenario subdivided into temporal sequences. The implicit animation controls the movement by implementing a physics‐based model and fuzzy constraints of position and orientation. It gives better configuration than the explicit animation because it takes into account the interactions between agents, and it gives a neat solution without the problems of complexity due to geometric modelling. A methodology based on the AI‐CAE technique is discussed, medical expertise and validation tests are presented. Copyright © 2011 John Wiley & Sons, Ltd.     

Experimental and numerical study of stress–strain state of pressurised cylindrical shells with external defects

Work presents the experimental technique with using of strain gauges for determining of strain distribution near longitudinal external defects of semielliptical shape in pressurised cylindrical shells and an appropriate procedure of numerical calculation based on a finite element method (FEM) for assessment of strain state near such defects. Numerical assessment of elastic stress distribution at bottom of external semielliptical notch in pressurised cylindrical shell is in a good agreement with the data received on the base of different analytical models. Here, the FEM results and data based on Glinka-Newport model are the most close for maximal stress. A comparison an experimental and calculation results showed on their acceptable coincidence and this fact gives the ground for using the numerical calculations instead labour-intensive and expensive experimental tests.     

Primary ciliary dyskinesia: diagnosis and standards of care

Primary ciliary dyskinesia (PCD) is characterized by disease of the upper and lower respiratory tract, in association with visceral mirror image arrangement in 50% of cases, due to abnormal structure and/or function of cilia. The purpose of this paper is to review the clinical features, diagnosis and management of PCD. Presentations include neonatal respiratory distress, recurrent lower respiratory tract infection, chronic rhinosinusitis and male infertility. PCD enters the differential diagnosis of bronchiectasis, atypical asthma, and unusually severe upper airway disease. Diagnosis is by a cascade of investigations, starting with the saccharin test in patients older than 10 yrs; ciliary beat frequency and pattern on light microscopy; and electron microscopy to assess ciliary morphology and orientation. It is important not to confuse primary and secondary ciliary abnormalities. Nasal nitric oxide is low in PCD, and this measurement shows promise as a screening test for PCD. Diagnosis is important, in order to prevent the development of bronchiectasis and to avoid any unnecessary otorhinolaryngological procedures. Regular follow-up is essential, and management should be multidisciplinary, with input from centres with a special interest in PCD, having access to paediatric and adult chest physicians, otolaryngologists and audiological physicians, physiotherapists, counselling services and fertility clinics. The prognosis is good, but morbidity can be considerable if PCD is incorrectly managed.     

Experimental study of generalized self-filtering unstable resonators in an ablative-wall flash-lamp-pumped dye laser

The performance of a generalized self-filtering unstable resonator (GSFUR) that consists of two curved mirrors in a nonconfocal scheme with a low magnification of M = -1.62 in an ablative-wall flash-lamp dye laser is reported. The objective was to study the near- and far-field intensity distribution and the divergence of the laser beam. It was found that the output beam has a nearly Gaussian distribution with a pulse duration of ~400 ns FWHM, almost independent of the diameter of the field-limiting aperture, but increases slightly with the pumping rate. A diffraction-limited laser beam of 1.1 mrad was obtained from this laser cavity. The output energy was ~1 mJ when an intracavity glass plate was used as an output coupler. The required relations needed for the GSFUR design were also derived.     

Differential effects of cyclo-oxygenase and thromboxane synthetase inhibition on ventilation-perfusion relationships in acid aspiration-induced acute lung injury

Cyclo-oxygenase metabolites are important regulators of pulmonary vascular and airway tone and may act to regulate ventilation-perfusion (VA/Q) relationships. Hypoxemia that follows aspiration of gastric acid is associated with increased venous admixture, and plasma levels of thromboxane (TX) B2 and 6-keto-PGF2 alpha are increased after experimental acid-induced acute lung injury. The present study was designed to determine the effects of cyclo-oxygenase metabolites on VA/Q relationships in canine acid aspiration. Eighteen anesthetized dogs received 0.2 mL/kg 0.1 N HCl intratracheally; six were pretreated with ibuprofen (IBU), a cyclo-oxygenase inhibitor, 12.5 mg/kg IV, and six other dogs received OKY-046 (OKY), a TX synthetase inhibitor, 0.5 mg/kg IV. The remaining six animals (ACID) served as controls. Continuous distributions of ventilation and perfusion were evaluated with the multiple inert gas elimination technique. Within 30 minutes, acid injury resulted in significant (p < 0.05) decreases in PaO2 from baseline values by 44.7 +/- 5.4 and 47.6 +/- 4.8 mm Hg in the ACID and OKY groups, respectively. Although decreased, the change in PaO2 of 21.0 +/- 4.8 mm Hg in IBU animals was significantly (p < 0.05) attenuated in comparison with the other groups. Ibuprofen increased pulmonary vascular resistance, attenuated perfusion to shunt and low VA/Q areas, and reduced ventilation to unperfused areas for the first 2 hours after acid injury (all p < 0.05), whereas OKY exacerbated hypoxemia and VA/Q inequality.(ABSTRACT TRUNCATED AT 250 WORDS)