Dividends

Groupe Laperriere &; Verreault Inc (GL&;V) has signed an agreement with its banking syndicate to redefine the terms of the bank credit arrangement set up in November 2002 for the acquisition of Eimco Process Equipment.     

Fourth Meeting on Fire Retardant Polymers

Abstract

The Fourth Meeting on Fire Retardant Polymers was held from September 9 to 11, 1992 in Albert-Ludwigs-University of Freiburg (Germany) by the Freiburg Materials Research Center (F.M.F). Close collaboration was provided by the University of Torino, Department of Chemistry. IPM. Torino (Italy), Universite Louis Pasteur and Ecole d'Application des Hauts Polymers-EAHF, Strasbourg (France), and the University of Kaiserslautern (Germany) with support from the European Polymer Federation (EPF) and the Groupe Francais des Polymers (GPF). The Organizing Committee included Chairman R. Miilhaupt (Germany), G. Camino (Italy). W. Becker (Germany), J. Brossas (France) and L. Costa (Italy).     

Dermatitis-inducing furanocoumarins on leaf surfaces of eight species of Rutaceous and Umbelliferous plants

Eight species of Rutaceae or Umbelliferae, known to cause or suspected of causing photophytodermatitis, had the linear furanocoumarins psoralen, bergapten, and xanthotoxin on their leaf surfaces, in concentrations varying from 0.014 to 1800 /gmg/g fresh weight, equivalent to 0.17–56% of the total leaf concentration. The higher percentage generally observed for spring leaves compared to autumn leaves suggests a higher rate of transfer of these furanocoumarins to the surface in the younger leaves. Among the plants studied,Ruta graveolens had the highest surface concentrations of all three furanocoumarins. The relatively high effectiveness in causing dermatitis of some species with low surface concentrations may be explained by a more effective mechanism of transfer of the furanocoumarins to the skin. A role in the defense of the plant is suggested by their accumulation on the plant surface.A paper based on the work reported here was presented at the Groupe Polyphénols conference, Brock University, St. Catharines, Ontario, Canada, August 19–19, 1988.     

Energy production from biomass pyrolysis: a new coefficient of pyrolytic valorisation

The use of renewable energy sources is becoming increasingly necessary to diminish the greenhouse effect gases production. Biomass is the most common form of renewable energy, widely used in the third world. Pyrolysis, which corresponds to the thermal decomposition of biomass under the action of heat and without any oxidant, is particularly well-adapted to the valorisation of lignocellulosic products such as wood or straw. The BIOCARB programme of the Commissariat à l'Energie Atomique (CEA), to which the Groupe de Recherche sur l'Environnement et la Chimie Atmosphérique (GRECA) contributes, aims to produce carburant from the gasification of biomass. This fuel can be either pure hydrogen, or gasoil produced by the Fischer-Tropsch process after the pyrolysis and syngas production. It is absolutely necessary to control the different parameters of the pyrolysis (gas composition, formation of tars) to maximise the production of hydrogen or syngas. The new coefficient of pyrolytic valorisation presented here helps to meet this requirement. This work presents also experiments on the pyrolysis of straw and fescue in a 550-650 °C temperature range with different residence times, on which was based our investigation.     

Comite international pour la caracterisation et la terminologie du carbone “Publication de 14 definitions”

The following is a French translation of the 14 definitions originally published in Carbon23, 601–603 (1985). Some notes concerning the different meanings of some English terms and their French equivalents are also included. Correspondence regarding this material should be sent to Prof. A. Marchand, Centre de Recherche Paul Pascal, Domaine Universitaire, 33405 Talence Cedex, France.

Résumé

On trouvera ci-dessous la traduction en français, effectuée sous l'égide du Groupe Français d'Etude des Carbones (G.F.E.C.), de 14 définitions publiées précédemment en anglais [Carbon23, 601–603 (1985)]. L'uge des divers termes français est parfois assez différent de l'uge de leurs équivalents anglais. Certaines définitions sont donc suivies des “observations des traducteurs” qui présentent les remarques nécesires aux scientifiques et techniciens francophones. Toute correspondence relative à ces définitions doit être adressée au Professeur A. Marchand (Centre de Recherche Paul Pascal, Domaine Universitaire. 33405 Talence Cédex, France).     

国内外己内酰胺生产现状及市场分析

世界上最大的5家己内酰胺生产商是德国BASF公司,生产能力为55.5万T/a;荷兰DSM公司,生产能力为42.0万t/a;美国Allied-Signal公司,生产能力为32.7万t/a;日本宇部兴产公司,生产能力为26.8万t/a;日本东丽公司,生产能力为17.0万t/a。这5家公司的已内酰胺生产能力合计为174万t/a,约占世界总产量的50％。中国目前有4套己内酰胺生产装置,岳阳巴陵鹰山石化厂,2000年生产能力为7万t/a;南京东方公司,生产能力为6万t/a;石家庄化纤公司,生产能力为5万t/a;浙江巨化公司锦纶厂,生产能力为0.45万t/a,全国合计年生产能力为18.45万t/a。国外己内酰胺的主要消费领域为纤维、工程塑料和食品包装膜;国内已内酰胺的主要消费领域为帘子布、民用丝、工程塑料,所占比例分别为70％、28％、2％。国内己内酰胺需求一直大于国内产量,但由于技术力量薄弱、资金有限及下游产品结构不合理等原因制约了己内酰胺的应用,目前国内的已内酰胺主要应用在中低档产品中,高档产品所需己内酰胺仍要依靠进口。     

Structure of AB block copolymers with a polypeptide block: Effect of the chain conformation

The structure of AB copolymers with a polypeptide block has been studied by X-ray diffraction, electron microscopy, infrared spectroscopy, and circular dichroism. Copolymers with a polyvinyl block (polybutadiene or polystyrene) and a hydrophobic polypeptide block (polybenzyl-L-glutamate or polycarbobenzoxy-L-lysine) exhibit a lamellar structure in the dry state and in solution in dioxane or in different chlorinated solvents. This lamellar structure consists of plane, parallel, equidistant sheets. Each sheet results from the superposition of two layers: one formed by the polyvinyl chains in amore or less random coil conformation, the other formed by the polypeptide chains in an α-helix conformation, arranged in a hexagonal array and generally folded. Copolymers with a polyvinyl block and a hydrophilic polypeptide block (poly-Llysine or poly-L-glutamic acid) exhibit a larnellar structure in water solution and in the dry state. The difference between this lamellar structure and the preceding one consists in the conformation of the polypeptide chains: an intramolecular mixture of coiled chains, α-helices, and β chains. Copolymers with a polysaccharide block and a hydrophobic polypeptide block exhibit in DMSO solution and in the dry state a lamellar structure similar to that of copolymers with a polyvinyl block and a hydrophobic polypeptide block.     

Measurement of short-term changes in heart rate and in plasma concentrations of cortisol and catecholamine in a small marsupial

Using a chronically placed jugular catheter and a silver electrode, it was possible to monitor short-term changes in the plasma concentration of cortisol and catecholamine in the marsupial sugar glider (Petaurus breviceps) and to monitor both heart and respiration rates. Males judged to be low in the social hierarchy of a particular group were exposed to the whole-body odor of a dominant male from the same social group, a foreign dominant male, or a castrate male. While there was no evidence of a change in any of the physiological parameters when a male was exposed to either a castrate male or a female, a rapid increase occurred in heart rate and plasma concentrations of cortisol, glucose and catecholamine when the donor was a dominant male from the same or a different social group.     

国内外乙二醇现状及发展前景

2005年,全球乙二醇的总生产能力为1779.2万t,总消费量为1605.5万t。预计到2010年总生产能力将达到约2821.0万t,总消费量将达到约2130.0万t。目前我国乙二醇的总生产能力为169.8万t,2005年产量为110.1万t,消费量为508.8万t,预计到2010年我国乙二醇的总生产能力将达到约400.0万t,消费量将达到约710.0万t。针对存在的问题,提出了我国乙二醇今后的发展建议。     

Alteration of fractured cementitious materials

The alteration of cement materials in a fractured repository was investigated by experimental and modelling techniques to predict the long-term evolution of a cementitious repository for the safety assessment of radioactive waste disposal. A flow-through experiment with an artificially fractured cement column sample was carried out, and the evolution of a chemical composition in discharged water and the distribution of mineral components in a solid matrix, which was dominated by the dissolution of portlandite and calcium-silicate hydrate (C-S-H), were observed. A coupling transport and chemical equilibrium calculation code, which includes a thermodynamic incongruent dissolution model of C-S-H, was developed to predict the alteration of the fractured cement materials. The advection transport of a component in a solution within a crack and the diffusion of a component in a solid matrix were modelled in the calculations. With the proposed model, the possible alteration of cement materials along a crack was described.     

国内外苯酚的供需现状及发展前景

目前,全球苯酚的总生产能力约为926万ta/,2004年总消费量为774.5万t,预计到2009年总消费量将达到约945.2万t。2005年我国苯酚的总生产能力约为54.0万ta/,产量为44.3万t,消费量约为73.3万t。预计到2007年和2010年我国苯酚的总生产能力将分别达到约85万ta/和110万ta/,消费量将分别达到约85.0万t和96.0万t。针对目前存在的问题,提出了我国苯酚今后的发展建议。     

A perspective on surrogate endpoints in controlled clinical trials

The last couple of decades have seen a large amount of activity in the area of surrogate marker and surrogate endpoint validation, both from a clinical and a statistical perspective. Prentice made a pivotal contribution in the context of a single trial. Subsequently, the framework he proposed has been discussed, criticized, and extended. An important class of extensions considers several rather than a single trial. Recently, a lot of work has been done in this so-called hierarchical or meta-analytic framework. In this paper, we review both the single trial and the hierarchical framework. A number of applications, scattered throughout the literature, are brought together. We outline the statistical issues involved in trying to validate surrogate endpoints. Clearly statistical evidence should only be seen as a component in a decision making process that also involves a number of clinical and biological considerations.     

Filamentary extrusion of microcellular polymers using a rapid decompressive element

An extrusion process for manufacturing microcellular plastics is presented. In the past, microcellular structures have been produced in batch processes by using a thermodynamic instability of a polymer/gas system. In order to utilize such a thermodynamic instability in a continuous extrusion process, a large amount of gas must be dissolved quickly in a molten plastic flowing in the machine, and a rapid drop in the gas solubility must be induced in the flowing polymer/gas solution. Since the solubility of a gas in a polymer is a sensitive function of pressure, a thermodynamic instability for producing a microcellular structure can be induced by rapidly lowering the pressure. This paper presents a means for continuously forming the polymer/gas solution at an industrial processing rate and a means of nucleating microcells in the polymer/gas solution using a nozzle. Finally, a process model for controlling the cell morphology is presented by identifying the key parameters that control microcellular foaming in a continuous process. The experimental results agree with theoretical analyses, confirming the fact that the processing pressure strongly affects the microcellular foaming process through its effects on the amount of gas dissolved in the polymer and the magnitude of the pressure drop in the nucleation device.     

Effects of abrupt expansion geometries on flow‐induced fiber orientation and concentration distributions in slit channel flows of fiber suspensions

Flow‐induced fiber orientation and concentration distributions were measured in channel flows of fiber suspension. The test fluids used are a concentrated fiber suspension (CFS), a semidilute one (SDFS), and a dilute one (DFS). The channel has a thin slit geometry with a 1:16 expansion. In the present work, fiber orientation and concentration distributions are quantitatively evaluated by direct observation of fibers even in the CFS flow. It is found that the weak fiber–fiber interaction of the SDFS largely affects the fiber orientation in the flow with a sudden change such as in the expansion flow, while it is ineffective upon the fiber orientation in the flow without a sudden change such as in the far downstream region. Fiber concentration in the CFS has a flat distribution over a channel width in both the entrance region of the expansion and the downstream region. However, fiber concentration distributions in the SDFS and the DFS have a small and a large peak near the sidewall in the entrance region, respectively, due to the fiber‐wall interaction at the channel wall. These peaks, however, disappeared in the far downstream region after the fibers passed through the expansion. POLYM. COMPOS., 26:660–670, 2005. © 2005 Society of Plastics Engineers.     

Solid concentration and velocity distributions in an annulus turbulent fluidized bed

Solid concentration and particle velocity distributions in the transition section of a?200 mm turbulent fluidized bed (TFB) and a?200 mm annulus turbulent fluidized bed (A-TFB) with a?50 mm central standpipe were mea-sured using a PV6D optical probe. It is concluded that in turbulent regime, the axial distribution of solid concen-tration in A-TFB was similar to that in TFB, but the former had a shorter transition section. The axial solid concentration distribution, probability density, and power spectral distributions revealed that the standpipe hin-dered the turbulence of gas–solid two-phase flow at a low superficial gas velocity. Consequently, the bottom flow of A-TFB approached the bubbling fluidization pattern. By contrast, the standpipe facilitated the turbulence at a high superficial gas velocity, thus making the bottom flow of A-TFB approach the fast fluidization pattern. Both the particle velocity and solid concentration distribution presented a unimodal distribution in A-TFB and TFB. However, the standpipe at a high gas velocity and in the transition or dilute phase section significantly affected the radial distribution of flow parameters, presenting a bimodal distribution with particle concentration higher near the internal and external wal s and in downward flow. Conversely, particle concentration in the middle an-nulus area was lower, and particles flowed upward. This result indicated that the standpipe destroyed the core-annular structure of TFB in the transition and dilute phase sections at a high gas velocity and also improved the particle distribution of TFB. In conclusion, the standpipe improved the fluidization quality and flow homogeneity at high gas velocity and in the transition or dilute phase section, but caused opposite phenomena at low gas ve-locity and in the dense-phase section.     

撑绿竹施肥时期试验研究

研究采用田间随机区组试验,通过对撑绿竹不同施肥时期处理的立竹数、胸径和秆材产量进行比较,寻求撑绿竹最佳的施肥时期.结果表明:与处理5(3、8、12月三次/a)的2007～2009年累计产量(25523.5·kg/hm2)相比,处理4(3、8月两次/a)、处理1(3月一次/a)、处理2(8月一次/a)和处理3(12月一次...     

苯乙烯的供需现状及发展前景

2005年,全球苯乙烯的总生产能力为2745.0万t/a,总消费量为2434.7万t。预计2010年总生产能力将达到约3786.0万t/a,总消费量将达到约3003.0万t。截止到2006年11月我国苯乙烯的总生产能力为285.5万t/a;2005年产量为125.0万t,消费量为405.0万t。预计2010年我国苯乙烯的总生产能力将达到约600.0万t/a,消费量将达到约580.0万t。针对存在的问题,提出了我国苯乙烯今后的发展建议。     

Electrolyte-resistance change due to an insulating sphere in contact with a disk electrode

This work is aimed at improving the quantitative analysis of the electrolyte-resistance (ER) fluctuations generated by two-phase systems with dispersed gaseous, liquid, or solid insulating entities in a conductive electrolyte. The primary potential distribution around a disk electrode in contact with a small insulating sphere, which simulates a spherical particle, drop, or gas bubble sitting on a disk electrode used as a sensor, was calculated with a collocation method in order to derive the increment in ER caused by the sphere. For a sphere of size equal to one-tenth of the electrode size, the values of the ER increments were found to be very low and to depend on the sphere position: 0.3% close to the edge of the electrode and 0.05% at its centre. Despite the influence of variations in the electrolyte temperature and of the approximate horizontality of the electrode, these low values could be measured experimentally by scanning insulating spheres of 1 and 2 mm in diameter above or in contact with a stainless steel electrode of 10 mm in diameter, using the motorized translation stage of a scanning electrochemical microscope and a home-made electronic device measuring low-amplitude ER fluctuations.     

A generalized computer simulation model for obtaining sol-gel distributions in infinite polymeric networks

Computer simulation is well-known to be a very efficient and powerful tool, applicable to a wide variety of situations. The present paper is concerned, in some detail, with a computer simulation model for obtaining the sol and gel fractions in polymeric networks. Apart from yielding the values of these parameters, even in situations that are characterized by a considerable amount of complexity, and where, as a consequence, the relevant mathematical procedures have not yet reached a stage of finality, the model developed in this paper can be of value in arriving at a satisfactory overall perspective of the chemical process as a whole. It yields results which enables one to answer such questions as where a crosslinking can occur or how the sol is distributed. Appropriate modifications that are called for in the model in investigating more complex situations are also indicated in the paper.