Control of Water Tree Length and Density in Cable Insulation Polyethylenes

This paper was presented at the IEEE International Symposium on Electrical Insulation, June 2006. ©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.Digital Object Identifier: 10.1109/ELINSL.2006.1665284The goal of this paper is to study the influence of the chemical crosslinking of polyethylene on the water tree initiation and propagation in polymer insulation. For this, the water tree resistances of crosslinked and thermoplastic low density polyethylene were compared. Three types of crosslinked polyethylene systems were evaluated: one containing only peroxide and the other two having, beside peroxide, a free retarding additive system. The results were compared with those obtained on their thermoplastic correspondents. The data show that there are differences in both the water tree length and density that can be ascribed to the polyethylene systems. However, only differences in the water tree density could be ascribed to the material form (thermoplastic or crosslinked). The observed results are consistent with differences, on microscopic level, in permittivities and local breakdown strengths.This work was partly supported by the Romanian Ministry of Education and Research, in the frame of Grant CNCSIS A-1461

Extraction of oak volatiles and ellagitannins compounds and sensory profile of wine aged with French winewoods subjected to different toasting methods: Behaviour during storage

a b s t r a c t In Merlot wines the evolution of volatile and non-volatile (ellagitannins) compounds extracted from winewoods while being macerated for 12 months was studied. Seven types of winewoods subjected to different toasting methods were used. Different rates of extraction, depending mainly on wood compounds origin (toasting or naturally present in wood) and on the watering process during toasting, were observed, which were reflected in sensory differences. Globally, volatile phenols together with aldehydes, phenols and lactones showed an increase with increasing maceration time. Ellagitannins were extracted faster during the first 3 months; after 6 months an important decrease was observed. Wines with winewoods subjected to watering during toasting were lower in ellagitannins concentrations and demonstrated the greatest decrease of these compounds during maceration. Astringency and bitterness intensified with increasing ellagitannins. Lactones induced positive sweetness sensations, whereas furanic and guaiacol compounds influenced bitterness and astringency. Spicy and vanilla descriptors were related to eugenol, vanillin and other odorous chemicals

Les Sources de Campos do Jordão

A região do Planalto de Campos do Jordão está situada na parte nordeste do Estado de São Paulo e é composta de rochas do pré-Cambriano, representadas essencialmente, por migmatitos homogêneos e heterogêneos. Esse complexo é cortado por numerosas carnadas de quartzito e dolomito, assim como por corpos de granito. Essas estruturas geológicas favorecem a emergência de fontes de contato ou de dissolução nos dolomitos. As fontes têm vazões bastante fortes mas fornecem águas pouco mineralizadas. Segundo as análises físico-químicas, constata-se a existência de 2 tipos de água: um tipo é proveniente de rochas graníticas e dolomíticas com teores de sais dissolvidos mais elevados; outro tipo emerge de rochas gnaissicas e de alteração refletindo uma circulação superficial. Segundo esses critérios e considerando sua origem pouco profunda as águas são classificadas como bicarbonatadas calcicas, calco-magnesianas ou cloretadas magnesianas. As águas de algumas fontes podem ser incluídas na categoria de águas minerais fracamente radioativas e as restantes como águas de mesa.La région du plateau de Campos do Jordão, située au NE de l'État de São Paulo, est formée par des roches précambriennes, essentiellement représentées par des migmatites homogènes et hétérogènes. De nombreux massifs granitiques et filons de quartzite et dolomite à pendage subvertical les recoupent longitudinalement. Telles structures géologiques font apparaître des sources de contact ou de dissolution dans les dolomites, sources à très forts débits, mais donnant des eaux peu minéralisées. D'après les résultats des analyses physico-chimiques, on peut mettre en évidence deux types d'eaux: un type provenant des roches granitiques et dolomitiques avec des teneurs en sels dissous plus élevées par rapport à celui qui provient des roches gneissiques et d'altération qui reflète une circulation superficielle. Suivant ces critères et en fonction de leur origine peu profunde, les eaux sont classées comme bicarbonatées caldque, calco-magnésiennes ou chlorurées magnésiennes. Leur faible minéralisation, aliée à la base radioactivité, les encadre dans la catégorie des eaux de table faiblement radioactives

Impact of oak wood ageing modalities on the (non)-volatile composition and sensory attributes of red wines

During fermentation or ageing of wines, oak wood is commonly used in form of barrels, casks or derived oak products (chips, winewoods, tankstaves, among others). It is well known that aroma, structure, astringency, bitterness, aromatic persistence and colour may change as a result of wine-wood contact. A full-scale experimentation was performed under different oak ageing conditions in order to evaluate colour, phenolic, aromatic and sensory differences among final red wines (9-months ageing). Oenological parameters and wine colour were not impacted by ageing modality. At the end of ageing, no differences were found in total phenolic and tannin contents. Regardless of the ageing modality, total content and profile of fruity volatiles were globally maintained with regard to control (? 86 %). In contrast, the higher the surface of wine-wood contact per unit of wine volume, the greater the extraction of woody aromas. Thus, barrels led to wines with the highest level of woody aromas (515-864 ?g/L), followed by cask modalities (430-470 ?g/L). From a sensory point of view, descriptors highlighting the woody character of wine (vanilla, spicy) were enhanced in all oak-aged wines when compared to control. However, our results indicate that a masking effect of fruity aroma by oak wood did not occur, since all modalities were perceived as fruity as the control. Thus, each oak ageing modality may lead to wines with a different woody character, without no impact on fruity perception, allowing wineries to achieve the targeted aromatic profile, good structure and just the right balance between fruity and woody aromas

Migration of polyphenols from natural and microagglomerated cork stoppers to hydroalcoholic solutions and their sensory impact

During bottling aging, the wine comes into contact with the cork stopper due to the horizontal position of the bottle. The release of compounds, such as cork phenolic compounds, thus take place between the cork and the wine, depending on the type of cork stopper and the surface treatments applied. Many publications describe the extraction of these phenolic compounds in wine or hydroalcoholic solutions from natural corks, but few address microagglomerated corks, which are increasingly used by winemakers to seal their bottles. The aim of this study was therefore to compare the polyphenols, mainly hydrolysable tannins, transferred from natural and microagglomerated corks treated with supercritical CO2 into hydroalcoholic solutions. For this purpose, polyphenols released in macerates of natural and microagglomerated cork stoppers were identified and quantified by HPLC-DAD-ESI-QQQ. Suberic acid was also quantified. In this study, despite the high intra-“natural cork stopper” variability, significant differences were found between both types of stoppers for all polyphenols, the agglomerated corks releasing significantly less polyphenols; i.e., 25 times less. In contrast, suberic acid was extracted from both types of corks in similar concentrations; therefore, its extractability was not impacted by the type of stopper. A sensory profile was also carried out on the macerates. Macerates of natural cork stoppers were perceived with notes of “cardboard, dust, plank, wood” and “cork taint” significantly higher than supercritical CO2 treated microagglomerated cork stopper macerates. Moreover, the natural cork macerate with the highest content in polyphenol was perceived as being more bitter than that of microagglomerated cork stoppers

Different application dosages of a specific inactivated dry yeast (SIDY) : effect on the polysaccharides, phenolic and volatile contents and color of Sauvignon blanc wines

Aim: The aims of this study were to (i) study the effect of different application dosages of a commercial specific inactivated dry yeast (SIDY) on several compounds (polysaccharides, phenolic and volatile compounds) and attributes (color parameters) related to the quality of white wines, and (ii) acquire better knowledge about the use of different dosages of SIDY in white wines with the objective to improve their quality. Methods and results: Three different dosages were applied (10, 20 and 40 g hL-1). Treated wines were followed after a contact time period of two months and after a bottle aging period of three months. Total phenolic content, color intensity, CIELab coordinates, polysaccharides, low molecular weight phenolic compounds and volatile compounds were evaluated. Conclusions: Higher dosages of this SIDY resulted in a greater release of polysaccharides into the wine. In parallel, a positive effect on the reduction or prevention of wine oxidation was observed due to the interaction with certain phenolic compounds. The application of the highest dosage seems to lead to an adsorption or retention effect of the major identified volatile compounds. This effect seems to be more evident after the contact time period than after the bottle storage period. Significance and impact of the study: This study can contribute to improve our knowledge on how applying different dosages of SIDY affects the physical and chemical quality of white wines.CONICYT-PAI, República de Chile (concurso nacional inserción en el sector productivo, convocatoria 2014) No. 781403003FONDECYT (República de Chile) 11140275FONDECYT (República de Chile) 1140882FONDEQUIP (República de Chile) EQM- 13012

Wine acidification methods: a review

Global warming is directly linked to a lower concentration in organic acids in grape berries, leading to higher pHs in wine. Because of this lack of acidity, many important factors are impacted, as wine acidity and pH play a crucial role in various equilibriums. Indeed, the lower acidity and the higher pH modify the parameters of wine, such as free and molecular sulfur dioxide availability, colour and sensory aspects. Therefore, it is an ongoing challenge for winemakers to deal with wine acidification and thus preserve wine physico-chemical properties and prevent early spoilage due to microbiological instability induced by high pH. Different acidification methods are allowed by the OIV, chemical acidification being one the most common, followed by physical acidification and microbiological acidification. This review examines these three methods of acidification. The first part details chemical acidification and gives a complete description of various organic acids used in winemaking, and their different properties and regulations; the second part focuses on physical acidification, such as cation exchange resins and electrodialysis; and the last part briefly reviews the novelty of microbiological acidification in wine