Desorption‐ and Decomposition‐Based Techniques for the Regeneration of Activated Carbon

Activated carbon (AC) is an adsorbent used in most adsorption processes related to micro removal of pollutants from the water phase, but the application is limited due to high costs and environmental issues related to the disposal after saturation. Different regeneration techniques, reducing costs and minimizing environmental impact, are reported for the reuse of saturated AC. These techniques can be performed via two separate strands: regeneration based only on desorption of adsorbed compounds in AC, or based on the decomposition of pollutants adsorbed on AC. Literature on the regeneration of saturated ACs is reviewed and promising techniques are highlighted. One of the most challenging bottlenecks preventing the commercial application of regeneration technologies is the difficulty of scaling‐up.     

Application of titanium machining chips in welding consumables for wear-resistant hardfacing

Equipment of sugar cane plants and mineral extraction are submitted to severe abrasive wear conditions. Welded hardfacings are usually applied to repair this kind of damage, where commercial chromium/carbon-rich welding consumables have usually been employed. In the present work we investigated the microstructure of experimental hardfacings made by addition of residues (chips) collected from the machining of ASTM F67 (unalloyed Ti, grade 4) alloy. Mixtures with different carbide-formers (Cr/Nb ferro-alloys) were also tested. Two layers of ‘pure’ chips (Ti), chips plus Fe–Cr (Ti–Cr), and chips plus Fe–Nb (Ti–Nb) were applied on low-carbon steel specimens by the GTAW/TIG process. The microstructure of hardfacing layers was observed by optical and scanning electron microscopy (SEM) equipped with EDS microanalysis. The microstructural characterization has determined that carbide distributions change significantly with the chemical nature of the hardfacing. SEM observations coupled with EDS microanalysis have confirmed the formation of complex carbides within the metal weld, whose stoichiometry was determined by X-ray diffraction (XRD) analysis. Mixed carbides of MC type and some cementite have been found. As a result it was suggested that use of ASTM F67 chips as carbide formers for composition of welding consumables can contribute to improved wear resistance of hardfacings, if compared with traditional chromium-based hardfacings.     

Student perceptions of model-based estimating

The use of building information modeling (BIM) is well established in architecture, engineering and construction. However, previous studies note a lack of BIM expertise in academia, leading to slow adoption and limited knowledge on which to base BIM-related content. To improve course development, it is important to understand students’ perceptions of BIM-related subject matter. This study exposed estimating students (n = 214) to a model-based quantity takeoff (QTO) tutorial using Revit. Students’ perceptions of a Revit-based BIM’s usefulness for easily providing reliable and accurate material quantities were measured using a pre-test, tutorial and post-test design. Results revealed significant differences in students’ mean levels of agreement that an accurate QTO is completed for an estimator with the click of a button when a design team generated BIM model is available. Results also revealed significant differences in students’ level of agreement that a Revit-based BIM makes performing QTO by hand obsolete. This study provides educators’ insight into students’ perceptions of BIM use in QTO. Understanding student perceptions is paramount for construction management educators when designing a course and attempting to convey the value of foundational estimating skills while acknowledging the existence of more technologically advance estimating methods. Limitations and opportunities for further research are discussed.     

Effect of Silicon and Graphite Degeneration on High-Temperature Oxidation of Ductile Cast Irons in Open Air

Oxidation of Metals - The use of high silicon ductile irons is increasing as they offer some advantages with respect to conventional pearlitic–ferritic grades such as high elongation at...     

Experimental Design Applied for Cost and Efficiency of Antioxidants in Biodiesel

Oxidation stability is a parameter of great importance for biodiesel quality control to both producers and subsequent consumers. To maintain the quality of biodiesel, currently the most effective and economical method is the addition of antioxidants that prevent or retard the biofuel oxidation reaction. In this study, efficiency and cost of synthetic antioxidants added to B100 biodiesel from soybean oil and pork fat were evaluated, using butylhydroxyanisole (BHA), butylhydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ), in pure form or in mixtures, according to a simplex-centroid mixture experimental design. Results demonstrate an increased induction period (IP) in all trials when compared to the control sample, and TBHQ was the only antioxidant alone that met all the specification standards, while BHT and BHA alone met only the American standard specifications. The antioxidant mixture that presented the highest synergistic effect was that of TBHQ and BHA. Multi-response optimization indicated an optimum formulation containing 75 % TBHQ and 25 % BHA with an IP of 7.27 h at 110 °C and the antioxidant mixture cost of 31.31 USD, to be added for a ton of biodiesel. This simplex-centroid mixture experimental design shows an ability to be applied in the biodiesel, oils and fats industry to evaluate the oxidation stability and the occurrence of synergism between different mixtures of synthetic or natural antioxidants and their costs.     

Hedgehog Signalling Modulates Immune Response and Protects against Experimental Autoimmune Encephalomyelitis

The Hedgehog (Hh) pathway is essential for the embryonic development and homeostatic maintenance of many adult tissues and organs. It has also been associated with some functions of the innate and adaptive immune system. However, its involvement in the immune response has not been well determined. Here we study the role of Hh signalling in the modulation of the immune response by using the Ptch-1-LacZ^+/− mouse model (hereinafter referred to as ptch^+/−), in which the hemizygous inactivation of Patched-1, the Hh receptor gene, causes the constitutive activation of Hh response genes. The in vitro TCR stimulation of spleen and lymph node (LN) T cells showed increased levels of Th2 cytokines (IL-4 and IL-10) in ptch^+/−cells compared to control cells from wild-type (wt) littermates, suggesting that the Th2 phenotype is favoured by Hh pathway activation. In addition, CD4⁺ cells secreted less IL-17, and the establishment of the Th1 phenotype was impaired in ptch^+/− mice. Consistently, in response to an inflammatory challenge by the induction of experimental autoimmune encephalomyelitis (EAE), ptch^+/− mice showed milder clinical scores and more minor spinal cord damage than wt mice. These results demonstrate a role for the Hh/ptch pathway in immune response modulation and highlight the usefulness of the ptch^+/− mouse model for the study of T-cell-mediated diseases and for the search for new therapeutic strategies in inflammatory diseases.     

Supervised Multivariate Analysis of Hyper-spectral NIR Images to Evaluate the Starch Index of Apples

Fruit maturity indexes are crucial in harvest time determination and commercial context. The harvest time of apples, matching the desired commercial characteristics, is assessed through starch–iodine test in practice. Fruit halves are dipped into iodine solution and patterns are visually evaluated by experts comparing them to reference charts. Aim of the work was to study the relationships of near infrared (NIR) spectral images (1,000–1,700 nm), starch/starch-free patterns visually assessed and RGB color images. Spectral images of 88 Golden Delicious Klon B apples were sampled at seven different maturity stages. Partial least-squares discriminant analysis (PLSDA) technique was used on hyper-spectral NIR images to classify single pixels using its NIR reflectance spectrum. The response variable (i.e. the classification for each pixel) was identified through the matching of single pixel obtained with the color images, segmented in two classes (starch and starch-free), and the NIR hyper-spectral matrix. Mean hyper-spectral classification obtained through PLSDA modeling on individual apple correctly classified 80.81% of the total pixels, while the unique model, i.e. a single model including all the fruits, resulted in 66.33%. In the latter case, the relationship with the RGB classification showed high values (Pearson correlation coefficient r = 0.95). The present work shows the feasibility of NIR imaging spectroscopy as a tool for apple fruit maturity determination, avoiding expert’s subjective interpretation by traditional starch index assignments.     

A Fluorometric Enzymatic Assay for Quantification of Steryl Glucosides in Biodiesel

Steryl glucosides (SG) are common contaminants in biodiesel that form precipitates, which form and cause problems due to fouling during transport and storage. Therefore, their quantification is necessary to assess the quality of this fuel. The methods currently available for SG analysis require expensive instrumentation, need a previous concentration step by solid‐phase extraction (SPE) or are of limited use for the quantitative assessment. We developed an enzymatic method for SG quantification in biodiesel samples based on the hydrolysis of the glucoside catalyzed by a broadly specific beta glucosidase and the subsequent determination of the glucose released by the reaction. The method is non‐expensive, sensitive and was adapted to 96‐well format fluorescence plate reader, making it useful for the parallel assay of multiple samples. The enzymatic assay presented here represent a valuable tool for both quality control and the development of improved biodiesel production and purification procedures.     

The relationship between environmental management systems and organizational innovations

This study provides empirical evidence of the nature of the relationship between environmental management systems and organizational innovations. Using a sample of Spanish manufacturing firms, the study reports on the implementation of the International Organization for Standardization (ISO) 14000 environmental quality standards and the relationship of such implementation with organizational innovations in the firm. The study presents several implications of interest for practitioners, academics, and policy makers. © 2012 Wiley Periodicals, Inc.