A new class of silicone resins for coatings

A new class of silicone has been developed for coatings or as coating additives. Cycloaliphatic silane monomers were prepared and reacted into more easily handled cyclic oligomers. These cyclic oligomers were ring-opened into siloxane polymers. The polymers were functionalized with a variety of groups, including: amino, glycidyl epoxide, cyclohexene epoxide, acrylic, and alkoxysilane. The cycloaliphatic silicones have been designed for a number of different curing conditions: (1) ambient temperature-cure (amino and glycidyl epoxide), (2) cationic ultraviolet (UV)-cure (cyclohexene epoxide), (3) radical UV-cure (acrylic), and (4) moisture-cure (alkoxysilane). The end usages thus far have been focused on silicone coatings; however, usage as coating additives will be a focus for future research. The cycloaliphatic silicone has been UV-cured with mixed sol–gel precursors for usage as aerospace coatings. The cycloaliphatic silicones have also been ambient temperature-cured for release coatings, and have application as anti-fouling coatings. The inherent low surface energy makes the cycloaliphatic silicones prime candidates for surface tension additives. Presented at the 2006 FutureCoat! Conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans, LA, on November 1–3, 2006.     

Design Verification through virtual prototyping techniques based on Systems Engineering

The increasing offer of software tools for product development introduces methodological questions to design engineers in terms of the easiness of tool integration and design activities’ sequencing. Nowadays, Design Verification and Validation through prototyping techniques have been enriched with software solutions enabling virtual prototyping to take more product’s behaviors into consideration during analysis and simulation. It is the case of the Systems Engineering module in CATIA? V6 that proposes a sequential “Requirements–Functional–Logical–Physical Design” (RFLP) approach to link conceptual design activities with 3D-models and simulation. Since some practitioners traditionally use these concepts, this article presents an analysis, based on action research, to evaluate the Design Verification activities as well as the tools integration offered by the new Product Lifecycle Management vision of CATIA? V6. The analysis enabled authors to refine and propose a model’s nature-dependent design method, enriched from the basic RFLP concept. Additionally, the presented results also showed the benefits of using integrated approaches when designing complex products, represented in a case study on virtual Design Verification of an automotive sub-system.     

Novel use of waste glass powder: Production of geopolymeric tiles

In industry, as well as in cities, a large amount of solid waste is produced, some of which is partially recycled or is disposed of in its entirety in landfills, thereby generating negative environmental effects. Of this waste, industrial waste glass from numerous application sources is a major source of pollution because only an estimated 30% is reused globally. In the search for an alternative outcome for waste, various applications have arisen, some of which are related to constructions sector. This research study concerns the use of waste from glass bottles, fluorescent lamps and soda-lime window glass, used in its entirety as a raw material in the manufacture of tiles by applying the technique of alkaline activation to generate an alkaline cementitious material. The feasibility of using the waste for the development of this type of cementitious material is enabled by the high content of silica in the glassy state. NaOH was used as activator in a concentration range from 4 to 10?M. Manually produced tiles, exhibit good properties as compressive strength of 178?(kg/cm²) and maximum load supported before rupture of 1006?(N). The use of these wastes contributes to environmental sustainability and generating more friendly building products.     

Synthesis of molecular sieves from Chilean kaolinites: 1. Synthesis of NaA type zeolites

The synthesis of NaA type zeolites has been studied at autogenous pressure using Chilean kaolins as starting materials. The ratios of SiO₂/Al₂O₃, Na₂O/SiO₂, H₂O/Na₂O have been set at 1.9 or 2.5, 0.6 or 1.0 and 50 or 90, respectively. Reaction times have been 5 or 15 h and reaction temperature 80 or 100°C. The influence of these parameters on the textural and structural properties of the zeolite has been studied. All samples have been characterized by X‐ray diffraction, infrared spectroscopy, scanning electron microscopy, differential thermal analysis and cation exchange capacity. The best conditions for synthesis are: SiO₂/Al₂O₃=2.5, Na₂O/SiO₂=1.0, H₂O/Na₂O=50 and 15 h reaction time at 100°C. © 1999 Society of Chemical Industry     

Synergism between Brønsted acid sites and metal sulfide particles in the hydrodesulfurization of thiophene on ultrastable Y zeolite catalysts W/USY and Ni/USY

The influence of the acidity of ultrastable Y (USY) zeolite-supported tungsten or nickel sulfide catalysts, prepared at different pH values, on thiophene hydrodesulfurization activity has been studied. The acidity affects the catalysts' deactivation. The results of the initial activity clearly show a synergic effect between the metal sulfide centers and the Brønsted acid sites present in the zeolites. © 1998 SCI     

Development of fragmentation models for solid fuel combustion and gasification as subroutines for inclusion in CFD codes

This work arises from substantial problems found in the modelling of the gasification and combustion of solid fuel, both coal and biomass in the following different systems:

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Coal fired non-slagging cyclone combustors.

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Pre-calciners on cement plant.

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Fuel rich inverted cyclone combustors used to simulate the time temperature history of large utility boilers.

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Cyclonic gasifiers for sawdust and direct firing of small gas turbines.

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Deposition studies for slagging and fouling in large utility boilers.

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Prediction of final carbon in ash from pulverised coal systems.

Commercial CFD codes such as Fluent are well developed and have well proven routines for lagrangian tracking of burning particles through complex flow fields. However what has become apparent in numerous studies is that existing models for solid fuel combustion can be adjusted to predict the initial flow field aerodynamics, sometimes the temperature, but fall down when particles have to be followed completely through a system. This is manifested with cyclone combustors and gasifiers via enhanced retention of burning particles in centrifugal force fields, which can only be resolved by changes in the particle size distribution and thus fragmentation as the particle gasify or burn. This problem also becomes apparent in studies of processes in pre-calciners and in deposition in large utility boilers and furnaces.The paper will review the literature of the fragmentation of pulverised coal and biomass during gasification, devolatilisation and combustion and relate it to observed phenomena in the type of system under consideration. The difficulties of incorporating models of fragmentation in CFD codes such as Fluent are discussed. Then the implementation of such a model in Fluent is described, together with results from a number of different systems. It is concluded that the model so implemented shows improved prediction in many difficult areas, but still needs development to better reflect actual fragmentation conditions in different experimental systems.It is concluded that the model needs to be further extended beyond the single step fragmentation at present used, especially to include many of the fine particles known to be generated in such systems.     

Phenolics and antioxidant capacity of table grape (Vitis vinifera L.) cultivars grown in Chile

Grapes (Vitis vinifera L.) possess health-promoting effects attributed to their supply of a wide variety of bioactive phenolics. Juice and skin fractions of 4 varieties of table grapes: Red Globe, Crimson Seedless, Autumn Royal, and Ribier were prepared to determine and compare their total phenolics content, antioxidant capacity (DPPH, FRAP, and ORAC), anthocyanins, and specific phenolics (caffeic acid, gallic acid, resveratrol, and catechin) content, since a series of positive health benefits are expected from the intake of any of these fractions. Higher amounts of total phenolics and antioxidant capacity were observed in the skin fractions (P < 0.05). Blue grapes (Autumn Royal and Ribier) exhibited higher phenolics content and antioxidant capacity (P < 0.05) than red grapes. The most abundant phenolic compound observed was catechin (P < 0.05). Significant correlations between the antioxidant capacity and total phenolics were observed in grape juice and skin fractions. Autumn Royal juice provides a very high amount of phenolics, anthocyanins, and exhibits the highest antioxidant capacity, offering the best health promoting properties compared with the other grape varieties studied. PRACTICAL APPLICATION: Grapes possess health-promoting effects attributed to their supply of a wide variety of bioactive phenolics. Grape juice made with blue grapes (Autumn Royal, Ribier) exhibit higher phenolics content and antioxidant capacity than juice elaborated with red grapes (Red Globe, Crimson Seedless). The skin is a good source of phenolics and has a high antioxidant capacity. Specific health-promoting phenolics are more abundant in blue grapes, mainly in their skin fraction, which should not be discarded.     

Development and optimisation by means of sensory analysis of new beverages based on different fruit juices and sherry wine vinegar

BACKGROUND: Despite the long history of sherry wine vinegar, new alternatives of consumption are being developed, with the aim of diversifying its market. Several new acetic‐based fruit juices have been developed by optimising the amount of sherry wine vinegar added to different fruit juices: apple, peach, orange and pineapple. Once the concentrations of wine vinegar were optimised by an expert panel, the aforementioned new acetic fruit juices were tasted by 86 consumers. Three different aspects were taken into account: habits of consumption of vinegar and fruit juices, gender and age. RESULTS: Based on the sensory analysis, 50 g kg^?1 of wine vinegar was the optimal and preferred amount of wine vinegar added to the apple, orange and peach juices, whereas 10 g kg^?1 was the favourite for the pineapple fruit. Based on the olfactory and gustatory impression, and ‘purchase intent’, the acetic beverages made from peach and pineapple juices were the most appreciated, followed by apple juice, while those obtained from orange juice were the least preferred by consumers. CONCLUSION: New opportunities for diversification of the oenological market could be possible as a result of the development of this type of new product which can be easily developed by any vinegar or fruit juice maker company. © 2012 Society of Chemical Industry     

Molecular characterization of Escherichia coli O157:H7 hide contamination routes: feedlot to harvest

This study was conducted to identify the origin of Escherichia coli O157:H7 contamination on steer hides at the time of harvest. Samples were collected from the feedlot, transport trailers, and packing plant holding pens and from the colons and hides of feedlot steers. A total of 50 hide samples were positive for E. coli O157:H7 in two geographical locations: the Midwest (25 positive hides) and Southwest (25 positive hides). Hide samples were screened, and the presence of E. coli O157: H7 was confirmed. E. coli O157:H7 isolates were fingerprinted by pulsed-field gel electrophoresis and subjected to multiplex PCR procedures for amplification of E. coli O157:H7 genes stx1, stx2, eaeA, fliC, rfbEO157, and hlyA. Feedlot water trough, pen floor, feed bunk, loading chute, truck trailer side wall and floor, packing plant holding pen floor and side rail, and packing plant cattle drinking water samples were positive for E. coli O157:H7. Pulsed-field gel electrophoresis banding patterns were analyzed after classifying isolates according to the marker genes present and according to packing plant. In this study, hide samples positive for E. coli O157:H7 were traced to other E. coli O157:H7-positive hide, colon, feedlot pen floor fecal, packing plant holding pen drinking water, and transport trailer side wall samples. Links were found between packing plant side rails, feedlot loading chutes, and feedlot pens and between truck trailer, different feedlots, and colons of multiple cattle. This study is the first in which genotypic matches have been made between E. coli O157:H7 isolates obtained from transport trailer side walls and those from cattle hide samples within the packing plant.     

Toxicity of a polymer-graphene oxide composite against bacterial planktonic cells, biofilms, and mammalian cells

It is critical to develop highly effective antimicrobial agents that are not harmful to humans and do not present adverse effects on the environment. Although antimicrobial studies of graphene-based nanomaterials are still quite limited, some researchers have paid particular attention to such nanocomposites as promising candidates for the next generation of antimicrobial agents. The polyvinyl-N-carbazole (PVK)-graphene oxide (GO) nanocomposite (PVK-GO), which contains only 3 wt% of GO well-dispersed in a 97 wt% PVK matrix, presents excellent antibacterial properties without significant cytotoxicity to mammalian cells. The high polymer content in this nanocomposite makes future large-scale material manufacturing possible in a high-yield process of adiabatic bulk polymerization. In this study, the toxicity of PVK-GO was assessed with planktonic microbial cells, biofilms, and NIH 3T3 fibroblast cells. The antibacterial effects were evaluated against two Gram-negative bacteria: Escherichia coli and Cupriavidus metallidurans; and two Gram-positive bacteria: Bacillus subtilis and Rhodococcus opacus. The results show that the PVK-GO nanocomposite presents higher antimicrobial effects than the pristine GO. The effectiveness of the PVK-GO in solution was demonstrated as the nanocomposite "encapsulated" the bacterial cells, which led to reduced microbial metabolic activity and cell death. The fact that the PVK-GO did not present significant cytotoxicity to fibroblast cells offers a great opportunity for potential applications in important biomedical and industrial fields.