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High-density polyethylene (HDPE) nanocomposites were prepared by a melting-compounding process with a polymethylsilsesquioxane (PMSQ) as nanofiller. In this process, the PMSQ nanoparticles were swollen in an organic solvent using a Ultra-Turrax system and sonication and blended with molten HDPE using a twin-screw extruder. This was followed by solvent removal. Nanocomposites with different PMSQ mass contents from 0 to 1% were prepared. The nanocomposites were characterized with Fourier transformed infrared, transmission electron microscopy, differential scanning calorimetry, scanning electron microscopy and by thermal conductivity. The mechanical and thermomechanical properties of the materials were studied. The HDPE–PMSQ nanocomposites presented a remarkable increase in the elastic modulus (E′) compared to the neat HDPE. The obtained mechanical and thermomechanical properties of HDPE–PMSQ nanocomposites were found to be related to the barrier effect of the PMSQ nanoparticles.

The ladder polymethylsilsesquioxane (PMSQ) nanoparticles with average diameter size of 15 and 20 nm were synthesized by hydrolysis and condensation of methyltrimethoxysilane (MTMS). An ex situ kinetic study in acidic medium of MTMS hydrolysis was followed by Raman spectroscopy. The PMSQ nanoparticles was studied by infrared spectroscopy, 29Si and 13C nuclear magnetic resonance and by X-ray diffraction. The thermal stability was examined by thermogravimetric analysis. PMSQ nanoparticles have a degradation temperature of 390 °C under nitrogen and 380 °C under oxygen, an excellent specific area (397.21 m2/g), a density of 1.42 g/m3 and hydrophobic surface (apparent contact angle 148° ± 3).

The forest floor of boreal forest stores large amounts of organic C that may react to a warming climate and increased N deposition. It is therefore crucial to assess the impact of these factors on the temperature sensitivity of this C pool to help predict future soil CO2 emissions from boreal forest soils to the atmosphere. In this study, soil warming (+2–4°C) and canopy N addition (CNA; +0.30–0.35 kg·N·ha-1·yr-1) were replicated along a topographic gradient (upper, back and lower slope) in a boreal forest in Quebec, Canada. After nine years of treatment, the forest floor was collected in each plot, and its organic C composition was characterized through solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Forest floor samples were incubated at four temperatures (16, 24, 32 and 40°C) and respiration rates (RR) measured to assess the temperature sensitivity of forest floor RR (Q10 = e10k) and basal RR (B). Both soil warming and CNA had no significant effect on forest floor chemistry (e.g., C, N, Ca and Mg content, amount of soil organic matter, pH, chemical functional groups). The NMR analyses did not show evidence of significant changes in the forest floor organic C quality. Nonetheless, a significant effect of soil warming on both the Q10 of RR and B was observed. On average, B was 72% lower and Q10 45% higher in the warmed, versus the control plots. This result implies that forest floor respiration will more strongly react to changes in soil temperature in a future warmer climate. CNA had no significant effect on the measured soil and respiration parameters, and no interaction effects with warming. In contrast, slope position had a significant effect on forest floor organic C quality. Upper slope plots had higher soil alkyl C:O-alkyl C ratios and lower B values than those in the lower slope, across all different treatments. This result likely resulted from a relative decrease in the labile C fraction in the upper slope, characterized by lower moisture levels. Our results point towards higher temperature sensitivity of RR under warmer conditions, accompanied by an overall down-regulation of RR at low temperatures (lower B). Since soil C quantity and quality were unaffected by the nine years of warming, the observed patterns could result from microbial adaptations to warming.

Transformer oils are vulnerable to moisture, which can have adverse effects including a dramatic reduction in dielectric strength, accelerating the aging of the solid insulation (cellulose depolymerization) and the formation of decompositional gasses at high temperatures. Moisture may be generated inside the transformer due to degradation of the oil-paper insulation or there may be ingress of moisture due to free-breathing arrangements. A moisture content exceeding 50% of oil saturation greatly reduces the breakdown voltage, resulting in catastrophic failures as well as the potential for transformer fires [1]. The detrimental effect of water within a transformer is not only limited to the breakdown voltage of the oil. The rate of degradation of paper insulation increases in direct proportion to the water content [2], [3]. Moisture also has a decisive effect on the maximum temperature that the transformer can run at before moisture-induced failure occurs. Consequently, transformer life expectancy can be calculated from water content and temperature [3]. A failure of transformer accessories such as condenser bushings sometimes leads to a transformer failure and long-term outage. Often, moisture is a cause of explosion for service-aged bushings [4].

The aim of this study was to compare gaseous and particulate matter (PM) emissions from the combustion of agricultural (switchgrass, fast-growing willow and the dried solid fraction of pig manure) and forest (wood mixture of Black Spruce and Jack Pine) biomasses in a small-scale unit (17.58 kW). Concentrations of CO2, CO, CH4, NO2, NH3, N2O, SO2, HCl, and H2O were measured by Fourier transform infrared spectroscopy and converted into emission rates. Opacity was also evaluated and particulates were sampled. Results showed significantly higher emissions of SO2, NO2 and PM with the combustion of agricultural biomass compared to the forest biomass. However, further studies should be carried out so regulations can be adapted in order to permit the combustion of agricultural biomass in small-scale combustion units.

Au cours des deux dernières décennies, la recherche partenariale connaît un essor important. Un essor associé à plusieurs facteurs dont le nouvel engouement manifesté par des chercheurs pour cette stratégie de recherche, le fait que nous observons une augmentation des demandes pour des activités de recherche provenant des milieux de la pratique ou encore en raison de l’importance que lui accordent les organismes subventionnaires. Dans le cadre de cet article, nous allons examiner ce mode de recherche à partir du point de vue des praticiens qui ont participé à des recherches partenariales au sein du Réseau québécois de recherche partenariale en économie sociale (RQRP-ÉS). L’analyse des entrevues réalisées auprès de praticiens nous révèlera les raisons de leur participation, les activités auxquelles ils ont pris part et les conditions identifiées par les praticiens pour assurer le bon déroulement d’une recherche partenariale.Partnership research: practitioners’ point of view in QuébecIn the last two decades, partnership research has been rediscovered. The renewal of this interest is directly linked to a positive change of attitudes of researchers, in response to an increase of requests from practitioners for University conducted research and a change of priority in organizations providing research funds. In this article, we will examine this research model in the light of work done in the Réseau québécois de recherche partenariale en économie sociale (RQRP-ÉS). We recently have done an inquiry with practitioners who where partners in research done in the RQRP-ÉS. We present here the results from those interviews in terms of their motivations to work in the context of an academic process of producing new knowledge, the kind of participation they were involved in the research process and finally the conditions of success in conducting that kind of research.La investigación en colaboración: el punto de vista de los investigadores en QuébecEn el transcurso de las dos últimas décadas, la investigación en colaboración ha experimentado un importante auge. Auge asociado a numerosos factores entre los cuales el nuevo interés masivo de los investigadores por esta estrategia de investigación. Observamos un aumento de la demanda por actividades de investigación que provienen de medios en contacto con la realidad social y también por el aumento de subvenciones por parte de diversos organismos. En el marco de este artículo examinamos este tipo de investigación desde el punto de vista de los que intervienen en estas investigaciones colaborativas en el seno del Réseau québécois de recherche partenariale en économie sociale (RQRP-ÉS). El análisis de las entrevistas realizadas sobre diferentes agentes que han realizado este tipo de investigación nos revela las razones de la participación: las actividades en las cuales han tomado parte y las condiciones por ellos delimitadas para que la investigación en colaboración entre diversos agentes sociales pueda ser bien llevada a cabo.

Long-term copper toxicity has been demonstrated in Scenedesmus quadricauda. Upon continuous exposure to copper ions at 250 μg/L, the algae responded by a sharp increase in the synthesis of complexing polypeptides to chelate Cu. Complexing polypeptides gradually decreased, as observed by six sampling tests over 732 h, resembling to a negative exponential curve. This gradual diminution is considered to be a prime mechanism of acclimation or of adaptation to a heavy metal contaminated environment.

Gassing of oil is defined scientifically as the chemical decomposition of certain hydrocarbons, under the impact of electrical and thermal stress. Indeed, the homolytic breakdown of vulnerable covalent bonds generates both small and large free radicals. The small ones become gases dissolved in the oil, while the large fractions generate insoluble colloidal suspensions. Currently, the electrical power industry believes that the gassing of oil is caused solely by hidden incipient electrical failures. Consequently, these are detected and diagnosed by periodic dissolved gas analysis (DGA). This paper provides experimental evidence that the formation in service conditions of undetected oil-born decay products is a contributing factor to the gassing of oil.

L’article qui suit presente le cadre de realisation des travaux de l’ARUC-ES. Cette section rappelle la genese du programme de recherche, ses objectifs, le partenariat qu’il implique et la facon dont les travaux sont conduits. Nous concluons cette section en presentant les principales lecons qui se degagent de notre experience et les defis qui sont toujours a relever. Au nombre de ces defis, nous retrouvons la question liee a l’eternel debat sur la finalite de l’economie sociale et la place et la fonction qu’elle occupe eu egard a la transformation d’ensemble du systeme socioeconomique de la societe quebecoise. Nous developperons quelques elements de reflexion sur cette question, ce qui nous permettra de presenter les trois elements cles qui structureront les travaux de l’ARUC-ES au cours des cinq prochaines annees.

This paper analyses the role of social economy-based local actors in developing social innovation in Montreal. On the basis of a case study in the garment industry, the paper analyses the role played by community economic development corporations in the economic and urban reconversion in the city. The paper has five sections: 1 the problems and the issues facing Montreal’s garment industry 2 the theoretical concepts used in the analysis, i.e., proximity, social innovation, and governance 3 a brief introduction of community economic development corporations (CDEC) in Montreal 4 presentation of a case study in which a CDEC promotes the implementation of a fashion designers’ cluster in a Montreal neighbourhood 5 the analysis of the specific role played by the CDEC in the development of this cluster. The paper shows that innovation is not the exclusive playing field of high-tech sectors and aims to expand our vision of innovation to include stakeholders who mobilise resources that are not academic but rather the result of institutionally and locally-based learning.

There is a general agreement that in service conditions the quality of insulating fluids gradually deteriorates under the impact of electrical, thermal and chemical stresses. An important side effect of oil gassing related to the invisible colloidal suspensions is also investigated. Two ASTM methods are used to monitor the deterioration of liquid insulation step by step. The results obtained using a laboratory-grade spectrophotometer and a ratio-turbidimeter indicate that the absorbance increases by a significant and easily observable margin with ageing rate. A comparison is made between the performances of a naphtenic commercial-based mineral oil and a synthetic and natural ester fluid. Under the same aging condition, the obtained results indicate that esters have a better capability to dissolve sludge. Currently, the gassing of oil is solely related to hidden incipient electrical failures. Consequently, these are detected and diagnosed by periodic dissolved gas analysis. The results performed in laboratory conditions reported in this contribution on oil stability under electrical stress indicate that, undetected oil-born decay products contribute to the gassing of oil.