Painéis fenólicos para aplicação em fachadas exteriores

Dissertação para obtenção do grau de Mestre em Engenharia Civil

Use of a cashew nut shell liquid resin as a potential replacement for phenolic resins in the preparation of panels - a review

The Cashew Nut Shell Liquid (CNSL) can be considered as a versatile raw material with wide applications in the form of surface coatings, paints and varnishes, as well as the production of polymers. Within this context, the chemical constituents of CNSL (anarcadic acid, cardanol, 2-cardol and methylcardol) become promising in the development of new materials components. Once separated, CNSL can be used in the research and development of additives, surfactants, pharmaceuticals, pesticides, polymers, resins and others. Being a byproduct, CNSL used in the preparation of new materials is characterized as a truly technological innovation.

Use of expert panels in highway safety: A critique

Expert panels have been used extensively in the development of the "Highway Safety Manual" to extract research information from highway safety experts. While the panels have been used to recommend agendas for new and continuing research, their primary role has been to develop accident modification factors—quantitative relationships between highway safety and various highway safety treatments. Because the expert panels derive quantitative information in a “qualitative” environment and because their findings can have significant impacts on highway safety investment decisions, the expert panel process should be described and critiqued. This paper is the first known written description and critique of the expert panel process and is intended to serve professionals wishing to conduct such panels.

Influence of parameters on the heterogeneous photocatalytic degradation of pesticides and phenolic contaminants in wastewater : a short review

In recent years, the application of heterogeneous photocatalytic water purification process has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible light spectrum. This paper aims to review and summarize the recently published works on the titanium dioxide (TiO2) photocatalytic oxidation of pesticides and phenolic compounds, predominant in storm and waste water effluents. The effect of various operating parameters on the photocatalytic degradation of pesticides and phenols are discussed. Results reported here suggested that the photocatalytic degradation of organic compounds depends on the type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, catalyst application mode, and calcinations temperature in water environment. A substantial amount of research has focused on the enhancement of TiO2 photocatalysis by modification with metal, non-metal and ion doping. Recent developments in TiO2 photocatalysis for the degradation of various pesticides and phenols are also highlighted in this review. It is evident from the literature survey that photocatalysis has shown good potential for the removal of various organic pollutants. However, still there is a need to find out the practical utility of this technique on commercial scale.

Comparative effects of thermal and high pressure processing on phenolic phytochemicals in different strawberry cultivars

Abstract It is widely considered that high pressure processing (HPP) results in better retention of micronutrients and phytochemicals compared to thermal pasteurization (TP), although some studies indicate that this may not be true in all cases. The aims of this study were (1) to objectively compare the effects of HPP under commercial processing conditions with thermal pasteurization (TP) on the stability of phenolic antioxidants in strawberries following processing and during storage and (2) to evaluate the influence of varietal differences and hence differences in biochemical composition of strawberries on the stability of phenolic antioxidants. Strawberry puree samples from cultivars Camarosa, Rubygem, and Festival were subjected to HPP (600 MPa/20 °C/5 min) and TP (88 °C/2 min). The activities of oxidative enzymes were evaluated before and after processing. Furthermore, the antioxidant capacity (total phenolic content (TPC), oxygen radical absorbance capacity (ORAC), and ferric reducing antioxidant power (FRAP)) and individual anthocyanins (by HPLC) were determined prior to and following processing and after three months of refrigerated storage (4 °C). Depending on the cultivar, HPP caused 15–38% and 20–33% inactivation of polyphenol oxidase and peroxidase, respectively, compared to almost complete inactivation of these enzymes by TP. Significant decreases (p < 0.05) in ORAC, FRAP, TPC and anthocyanin contents were observed during processing and storage of both HPP and TP samples. Anthocyanins were the most affected with only 19–25% retention after three months of refrigerated storage (4 °C). Slightly higher (p < 0.05) loss of TPC and antioxidant capacity were observed during storage of HPP samples compared to TP. Industrial Relevance: The results of the study demonstrated that both high pressure processing and thermal pasteurization result in high retention of phenolic phytochemicals in strawberry products. Under the conditions investigated, high pressure processing did not result in a better retention of phenolic phytochemicals compared to thermal pasteurization. In fact, a slightly higher loss of total polyphenol content and antioxidant capacity were observed during refrigerated storage of HPP processed samples. Our results showed that, high pressure processing may not always be a better alternative to thermal processing for strawberry puree processing if the main objective is better retention of phenolic antioxidants. However, it should be noted that other quality attributes such as sensory properties, where distinct advantages of HPP are expected, were outside the scope of this study.

Inhibition of the biosynthesis of sterols by phenyl and phenolic compounds in rat liver

The presence of mitochondria increased the incorporation of [2-14C]mevalonate into sterols in a cell-free system from rat liver. Various phenyl and phenolic compounds inhibited the incorporation of mevalonate when added in vitro. p-Hydroxycinnamate, a metabolite of tyrosine, was the most powerful inhibitor among the compounds tested. Catechol, resorcinol and quinol were inhibitory at high concentrations. Organic acids lacking an aromatic ring were not inhibitory. Two hypocholesterolaemic drugs, Clofibrate (α-p-chlorophenoxyisobutyrate) and Clofenapate [α,4-(p-chlorophenyl)phenoxyisobutyrate], which are known to affect some step before the formation of mevalonate in the biosynthesis of cholesterol in vivo, showed inhibition at a step beyond the formation of mevalonate in vitro. The presence of the aromatic ring and the carboxyl group in a molecule appears to be necessary for the inhibition.

Inhibition of the biosynthesis of isoprenoid compounds by phenolic acids in the rat brain

The incorporation of [2-14C]mevalonate into nonsaponifiable lipids by rat brain homogenates is inhibited by phenolic acids derived from tyrosine. The phenyl acids derived from phenylalanine are inhibitory only at very high concentrations compared with phenolic acids. The brain is more sensitive to inhibition by the phenolic acids than the liver. These studies indicate a possible role for phenolic acids in the impairment of cerebral sterol metabolism in phenylketonuria.

The metabolism of phenolic acids in the rat

Some of the enzyme systems in the formation of p-hydroxybenzoate from tyrosine have been studied in the rat liver in vitro. The conversion of p-hydroxycinnamate into p-hydroxybenzoate, which was found in rat liver mitochondria showed a number of differences when compared with the b-oxidation of fatty acids. Studies with p-hydroxy[U-14C]cinnamate indicated that 14CO2 was released during the formation of p-hydroxybenzoate. The formation of p-hydroxycinnamate from tyrosine of p-hydroxyphenyl-lactate could not be demonstrated in vitro. The interconversion of p-hydroxycinnamate and p-hydroxyphenylpropionate was demonstrated in rat liver mitochondria.

Ultimate Strength of RC Wall Panels in One-Way In-Plane Action

Test results of 24 reinforced concrete wall panels in one-way in-plane action are presented. The panels were loaded at a small eccentricity to reflect possible eccentric loading in practice. Influences of slenderness ratio, aspect ratio, vertical steel, and horizontal steel on the ultimate load are studied. An empirical equation modifying two existing methods is proposed for the prediction of ultimate load. The modified equation includes the effects of slenderness ratio, amount of vertical steel, and aspect ratio. The results predicted by the proposed modified method and five other available equations are compared with 48 test data. The proposed modified equation is found to be satisfactory and, additionally, includes the effect of aspect ratio which is not present in other methods.

Ultimate Strength of R.C. Wall Panels in Two-Way In-Plane Action

Test results of 24 reinforced concrete wall panels in two-way action (i.e., supported on all the four sides) and subjected to in-plane vertical load are presented. The load is applied at an eccentricity to represent possible accidental eccentricity that occurs in practice due to constructional imperfections. Influences of aspect ratio, thinness ratio, slendemess ratio, vertical steel, and horizontal steel on the ultimate load are studied. Two equations are proposed to predict the ultimate load carried by the panels. The first equation is empirical and is arrived at from trial and error fitting with test data. The second equation is semi-empirical and is developed from a modification of the buckling strength of thin rectangular plates. Both the equations are formulated so as to give a safe prediction of a large portion of ultimate strength test results. Also, ultimate load cracking load and lateral deflections of identical panels in two-way action (all four sides supported) and oneway action (top and bottom sides only supported) are compared.