Non-destructive detection of surface-bond defects in carbon composite-strengthened concrete structures

For almost 15 years, carbon fibre-reinforced polymer (CFRP) plates and sheets have been used for strengthening and repair of civil engineering structures. CFRP plates were applied to upgrade structures for change in use or increasing traffic load. CFRP laminates have also been used to repair deteriorated structures such as multi-storey parking or bridges. The execution quality and condition of the strengthening measure in terms of bond integrity were neither monitored nor tested systematically. Inspectors eventually applied simple hammer knocking during regular main inspection for subjective noise distinction as a measure for eventual insufficient bond. This paper presents the feasibility and the limitations of low-frequency transversal ultrasonic waves with dry-coupling point-contact sensors for inspection and defect detection between CFRP laminate and concrete surfaces. The German Centre of Competence in Civil Engineering (DIBt) has initiated a national research project [Helmerich et al. (2012). Condition analysis of bonded CFRP-applications on concrete structures by means of non-destructive testing [in German: Zustandsuntersuchung von CFK-Klebeverstärkungen an Betonbauteilen mittels zerstörungsfreier Prüfung (ZfP)]. Final, internal project report], carried out at the Federal Institute for Materials Research and Testing (BAM), Germany. The aim of the project was to present a potential non-destructive testing method for bond defect detection as a measure for the durability of the strengthening system more than 10 years after application.     

Nonlinear regularized reaction-diffusion filters for denoising of images with textures

Denoising is always a challenging problem in natural imaging and geophysical data processing. In this paper, we consider the denoising of texture images using a nonlinear reaction-diffusion equation and directional wavelet frames. In our model, a curvelet shrinkage is used for regularization of the diffusion process to preserve important features in the diffusion smoothing and a wave atom shrinkage is used as the reaction in order to preserve and enhance interesting oriented textures. We derive a digital reaction-diffusion filter that lives on graphs and show convergence of the corresponding iteration process. Experimental results and comparisons show very good performance of the proposed model for texture-preserving denoising.     

Synthesis of new open‐chain alkoxyamines and their evaluation for nitroxide‐mediated radical polymerization

New readily available open‐chain alkoxyamines have been synthesized and evaluated as unimolecular initiators for nitroxide‐mediated radical polymerization of styrene and n‐butyl acrylate. The observed moderate control of polymerization is explained by the low thermostability of the parent nitroxide. Copyright © 2004 Society of Chemical Industry     

Untersuchungen zur Betriebscharakteristik pulsierter Füllkörperkolonnen für die Flüssig/Flüssig-Extraktion

Studies on the operating characteristics of pulsed packed-columns for liquid/liquid extraction. The dependence of capacity limit and extraction efficiency on the operating conditions, the properties, and the packing material is illustrated with the aid of experiments on two test mixtures in pilot plant columns. The direction of mass transfer has a large influence on the capacity limit and extraction efficiency. From the practical point of view, the operating characteristics of pulsed packed-columns provide the chemical engineer with reference data for the estimation of column dimensions and rational planning of pilot plant experiments. Methods for the precalculation of capacity limits and extraction efficiencies of pulsed packed-columns are reported in the literature. A comparison of the results obtained by these methods with the experimental data indicates the feasibilities and limits of such a calculation.     

Lipoprotein lipase in cholesterol-fed and control guinea pigs

A study of the in vitro activity of lipoprotein lipase of guinea pigs has shown that (a) the lipolytic activity of activated post-heparin serum is depressed in hypercholesteremic guinea pigs compared to the serum of normocholesteremic guinea pigs; and (b) this depressed lipolytic activity in hypercholesteremic guinea pigs is not due to the presence of an inhibitor.     

Koaleszenzprobleme in chemischen Prozessen

Coalescence problems in chemical processes . Separation of liquid/liquid dispersions is a process step which often gives rise to considerable difficulties on an industrial scale. A number of selected examples taken from chemical processes demonstrates where phase separations occur, the consequences they may have, and what industrially practicable methods are available for their solution. The problem analysis presented starts from the mechanism of generation of the dispersion and leads to a qualitative characterization of the various coalescence problems without presuming any knowledge of the droplet spectrum. This procedure acquires important knowledge from an assessment of prior process steps. Measures for improvement are deduced from the causes of poor phase separation: modification of physical properties, change of dispersion, use of mechanical separation aids (packings, coalescing filters), application of an electrical field, centrifuges and hydrocyclones, coalescence-promoting chemical additives. Industrially applicable methods are reported for design of equipment for implementation of these approaches.     

Man-made linear flow paths at catchment scale: Identification, factors and consequences for the efficiency of vegetated filter strips

A vegetated filter strip (VFS) gains the best retention potential when surface runoff enters the strip as sheet runoff. However, surface runoff convergence may take place in linear flow structures long before approaching the river system. Limited information is available about the extent of these linear flow pathways and the factors that may influence their occurrence in the landscape. To better understand these effects, we carried out detailed field surveys in ten small headwater catchments in different climatic regions in Austria. Ditches and channels directly connected to the stream network were mapped. Surface flow pathways were calculated either with or without integrating the mapped structures. Effective placement of retention structures may also be influenced by the accuracy of digital elevation model (DEM) resolution. We therefore used three different DEMs with varying resolution. The catchment areas connected directly to the stream network via linear drainage structures were identified. In seven out of the ten catchments such unprotected areas (UA) were found. Their extent varied between 10% and 38% of the total catchment area. Factors influencing the extent of UA were length of the road network and annual precipitation. Without integrating the mapped linear structures, UA could not be detected in the broad-gridded DEMs. After integration of mapped linear structures, DEM resolution did not influence the calculated extent of UA. For our environmental setting, GIS-based design of placement of retention structures leads to considerable errors and should be verified by fieldwork.     

Brief coping skills treatment for cocaine abuse: 12-month substance use outcomes.

Patients (N?=?108) in a study of cocaine-specific coping skills training (CST), which was found to reduce cocaine use during a 3-month follow-up, were followed for an additional 9 months. CST involved coping skills training in the context of high-risk situations. Control treatment used meditation-relaxation. Both were added to comprehensive private substance abuse treatment. Patients in CST who relapsed had significantly fewer cocaine use days than did the control group during the first 6 months, then both conditions did equally well. Patients in CST also drank alcohol more frequently in the last 6 months than did contrast patients but did not differ in heavy drinking days. For cocaine use outcomes, no interaction of treatment was found with gender, education, route of administration, drug use severity, sociopathy, or depression. Implications include the need to investigate different lengths and combinations of treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thirty years after Harrison and Saeed: Does the medium make the message?

In 1977, Harrison and Saeed published what became the classic study of personal advertisements. They found that women tended to offer youth and attractiveness, while seeking financial security or wealth. Men, in turn, sought youth and attractiveness, while offering financial security. The purpose of the current study was to determine if changes in the medium used for personal ads (Internet versus print) has had an impact on stated preferences in mate selection. Our results duplicated the Harrison and Saeed (1977) findings, suggesting that neither the medium, nor the societal changes of the last 30 years, have had any effect on mate selection. In a supplementary analysis of women in the 50–69 age group, however, we found that these women were less willing to date older men, preferring younger partners.