Vision-based quantitative assessment of microcracks on reactor internal components of nuclear power plants

Ageing power facilities are increasingly susceptible to the onset of damage related to long exposure to stress, radiation, elevated temperatures and environmental conditions. One failure mechanism of particular concern is the onset of stress corrosion cracking. Currently, a technician manually measures the crack thicknesses at few points along a microcrack in a microscopic image, and the results are quantified by the Root Mean Square (RMS) of these measurements. This approach is time-consuming and subjective. In addition, the crack thickness is an important but difficult characteristic to accurately describe in a single numerical value, since it can vary considerably along the length of a crack. In this paper, a vision-based methodology is proposed for accurate quantification of microcracks that provides the thickness measurements for each pixel along the crack centreline. The proposed approach provides the minimum, maximum, mean, standard deviation, RMS and the histogram of crack thicknesses, which in most cases yields thousands of measurements. This approach provides more comprehensive insight regarding the condition of a microcrack. A region-growing method is used for segmenting microcracks from complex backgrounds. The microcrack thicknesses are then automatically computed along the lines orthogonal to the crack centreline. The fast marching method is used to accurately estimate the centreline of microcracks. Several real microcracks are examined to evaluate the performance of the proposed methodology.     

Behavior of T-shaped reinforced concrete beams partially confined by structural steel

External confinement of reinforced concrete (R/C) members with structural steel sections or fiber reinforcing wraps is commonly used to improve the flexural behavior of structural members. Flexural strengthening of R/C beams by external steel members is among the most effective and convenient techniques. A study is presented in this paper investigating the flexural behavior of R/C beams having T cross-sections partially confined (P/C) by a combination of various steel members connected together by intermittent batten plates. Four R/C specimens, representing dropped beams in solid slabs, were tested. One control beam had no confinement whereas the three other beams had four steel angles simply wrapped and tied around the stem by batten plates, two angles at the bottom corners of the stem and the other two angles at the stem-flange junctions. Two plates were placed on the top surface of the flange and connected by studs to the two angles at the bottom of the flange. The resulting P/C beams are categorized as partial composite beams because no shear connectors were used between the R/C beam and the jacketing bottom-tension steel angles as in the case of conventional composite beams. All specimens were tested in positive bending under two points loading. Test results revealed an enhancement in the flexural behavior, particularly in the post-yield range of loading, and ductility due to the proposed strengthening and partial composite effect. The number and spacing of the intermittent battens played a significant role in the behavior of the strengthened specimens. Analytical values of loads and deformations at yield and ultimate loading showed good agreement with the measured values.     

Achieving dialogue with children with severe autism in an adaptive multisensory interaction: the "MEDIAte" project

This paper presents an adaptive physical environment that allows children with severe autism to successfully interact with multimodal stimuli, giving them a sense of control of the interaction and, hence, providing them with a sense of agency. This has been an extremely important effort for two main reasons: 1) This user group cannot be typified, hence making the design of an interactive system to fit all the spectrum of individuals a very complex task; 2) each individual PAS (person on the autistic spectrum) user must be able to develop himself within the environment according to his own capacities and potentiality. Qualitative evaluation by psychologists shows very good results and sketches an encouraging future for research on these environments.     

Integrated planning information systems: Context, design requirements, and prospects

This research contributes to the theoretical basis for appropriate design of computer-based, integrated planning information systems. The research provides a framework for integrating relevant knowledge, theory, methods, and technology. Criteria for appropriate system design are clarified. The requirements for a conceptual system design are developed based on “diffusion of innovation” theory, lessons learned in the adoption and use of existing planning information systems, current information-processing technology (including expert system technology), and methodology for evaluation of mitigation strategies for disaster events. Research findings focus on the assessment of new information systems technology. Chief among these findings is the utility of case-based reasoning for discovering and formalizing the meta rules needed by expert systems, the role of the “diffusion of innovation” theory in establishing design criteria, and the definition of client interests served by integrated planning information systems. The work concludes with the selection of a prototyping exercise. The prototype is developed in a forthcoming technical paper (Masri & Moore, 1994).     

Lipase-mediated plant oil hydrolysis—Toward a quantitative glycerol recovery for the synthesis of pure allyl alcohol and acrylonitrile

Plant based triacylglycerides are a sustainable feedstock for the chemical, bioenergy, food and cosmetic sector. While fatty acids conversion has been intensively studied, processes for glycerol valorization have been scarce. In contrast to chemical hydrolysis of plant triacylglycerides enzymatic hydrolysis methods provide a cleaner glycerol stream. This study focuses on the selection of a commercial lipase capable of quantitative hydrolysis of rapeseed- and high oleic sunflower oils. Enzymatic process using only water as the reaction medium allows simplified recovery of pure glycerol. Among the six commercial lipase preparations tested, Candida rugosa lipase was identified as the most effective biocatalyst. Catalytic behavior in buffer and pure water was equivalent. Glycerol generated using a washed lipase was recovered by just three purification steps. The FTIR spectrum of the recovered glycerol was equivalent to pure glycerol standard. Over the entire recovery process, 82%–88% of the theoretical glycerol yield could be obtained. Purified glycerol was further didehydroxylated to allyl alcohol by a formic acid mediated open distillation process. The enriched allyl alcohol had a quality, which allows to use it for the synthesis of bio-based acrylonitrile.     

Fault localization based on information flow coverage

Failures triggered by hard to debug defects usually involve complex interactions between many program elements. This paper hypothesizes that information flows present a good model for such interactions and presents a new fault localization technique based on information flow coverage. Using a test suite, the technique ranks the statements in a program in terms of their likelihood of being faulty by comparing the information flows induced by the failing runs with the ones induced by the passing runs. The ranking of the statements associated with a given flow is primarily determined by contrasting the percentage of failing runs to the percentage of passing runs that induced it. Generally, a higher percentage of failing runs implies a higher rank. To show its potential, the technique was applied to several open‐source Java programs and was compared, with respect to its fault localization effectiveness, with three other coverage techniques that use similar style metrics that are defined for statements, branches, and def–use pairs, respectively. The results revealed that information flow, branch, and def–use coverage performed consistently better than statement coverage. In addition, in a considerable number of cases information flow coverage performed better than branch and def–use coverage. Specifically, it was always safer but not always more precise. Copyright © 2009 John Wiley & Sons, Ltd.