Measurements of Air Leakage through Revolving Doors of Institutional Building

Exterior doors and entrances of nonresidential buildings are major sources of energy losses caused by air infiltration or exfiltration due to the frequent use of doors and the pressure difference across each door, created by the wind, stack effect, or ventilation systems. Information regarding the air leakage characteristics of manually or power-operated revolving doors is available in the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE) publications, based on studies carried out in the 1950s and 1960s. This paper presents results from a recent study carried out to investigate the air leakage characteristics of four revolving doors of a large institutional building in Montreal. These results are compared with data available in ASHRAE publications, as well as with the specifications of the Model National Energy Code of Canada for Buildings and ASHRAE Standard 90.1. The impact of the quality of seals on the annual heating costs is also evaluated.     

Cold weldability of aluminium: Contribution of the mechanical loadings to the formation of metallic bonds

In solid-state welding, temperature generally has an important role (diffusion, recrystallization, etc.) however, a mechanical loading is also necessary for breaking down the thin oxide layer (Al₂O₃) which naturally covers aluminium alloys. As the oxide layers have a melting point of around 2000 °C meanwhile aluminium alloys generally melt at only 600 °C; the heat supply alone cannot lead to the welding and a mechanical loading is always needed. This work aims at understanding the influence of the mechanical loadings on the formation of metallic bonds. To this end a new weldability test has been introduced. A symmetric cyclic shear is run on the welding interface without external heat supply. A tube-shaped sample is cut through its cross-section and undergone both a compression and a cyclic torsion loading. The influence of some parameters has been studied. Among them, surface condition (roughness and cleanliness), torsion angle (low amplitude) and number of cycles are the most significant. The welded joints have been then mechanically tested and microscopically observed (FEG-SEM and EBSD): the joining is achieved on a 1.5 μm thick layer, as things stand, on about 50% of the welding interface. Moreover, a thermomechanical model concludes that the internal intrinsic heat involved in this experimental process is too low to imply a significant increase of temperature in the specimen; thus the joining is only achieved due to mechanical effects of elastoplastic type.     

Technico‐economical assessment of MFI‐type zeolite membranes for CO2 capture from postcombustion flue gases

A detailed survey of the effect of moisture on the CO₂/N₂ permeation and separation performance of Mobile Five (MFI) zeolite membranes in view of downstream postcombustion CO₂ capture applications in power plants and incinerators is presented. The membranes, displaying a nanocomposite architecture, have been prepared on α‐alumina tubes by pore‐plugging hydrothermal synthesis at 443 K for 89 h using a precursor clear solution with molar composition 1 SiO₂:0.45 tetrapropylammonium hydroxide:27.8 H₂O. The synthesized membranes present reasonable permeation and CO₂/N₂ separation properties even in the presence of high water concentrations in the gas stream. A critical discussion is also provided on the technico‐economical feasibility (i.e., CO₂ recovery, CO₂ purity in the permeate, module volume, and energy consumption) of a membrane cascade unit for CO₂ capture and liquefaction/supercritical storage from standard flue gases emitted from an incinerator. Our results suggest that the permeate pressure should be kept under primary vacuum to promote the CO₂ driving force within the membrane. © 2011 American Institute of Chemical Engineers AIChE J, 58: 3183–3194, 2012     

Fat and salt contents affect the in-mouth temporal sodium release and saltiness perception of chicken sausages

In cooked meats, sodium chloride is involved in taste, texture and flavour release. So a reduction in the salt content may have an impact on overall perception and acceptability. The aim of this study was to evaluate the influence of composition on sodium release and saltiness intensity in chicken sausages. The rheological properties of the sausages differed according to composition. Temporal sodium release and temporal saltiness intensity were evaluated by four selected subjects when eating sausages. At each time point, the effect of the salt level in sausages on sodium release was positive and highly significant. The effect of lipids on sodium release was negative. Concerning perception, the amount of salt used had a positive effect on saltiness intensity, and lipids seemed to exert a masking effect. Generally, clear relationships between salt levels, sodium release and saltiness intensity were found but the masking effect of lipids on saltiness intensity probably also involved texture or fat perception mechanisms.     

An international study on the importance of androstenone and skatole for boar taint: IV. Simulation studies on consumer dissatisfaction with entire male pork and the effect of sorting carcasses on the slaughter line, main conclusions and recommendations

An international study has been conducted in order to determine the respective contributions of androstenone and skatole to boar taint and their possible variations according to production systems and consumer populations. The presentation of the study and the main results concerning skatole and androstenone levels and data from sensory evaluation or consumer surveys are reported in companion papers. The present paper summarises the main conclusions of the study and gives tentative recommendations. A simulation study was conducted, based on the skatole and androstenone levels currently observed in European populations of entire male pigs and on the results of the consumer surveys. The first part of the simulation study demonstrated that, overall, 6.5% (odour) and 3.0% (flavour) more consumers were dissatisfied with entire male than with gilt pork. The differences were, however, very variable according to countries. Consumer dissatisfaction for the odour of entire male pork was mostly associated with high skatole levels, while androstenone had little influence on it. On the other hand, androstenone and skatole had similar contributions to the level of dissatisfaction for flavour. From the present study it is not possible to determine clear cut-off levels for androstenone/skatole. The regression equations presented in [Matthews, K. R., Homer, D. B., Punter, P., Béague, M. P., Gispert, M., Siret, F., Leask, H., Fonti i Furnols, M., & Bonneau, M. (2000). An international study on the importance of androstenone, skatole for boar taint: III. Consumer survey in seven European countries. Meat Science, 54, 271-283] provide a basis for decision making. However, due to methodological limitations, the results may underestimate consumer reaction to entire male pork. The second part of the simulation study demonstrated that sorting carcasses on the basis of androstenone/skatole would reduce, but not eliminate, differences in consumer dissatisfaction between entire male and gilt pork. For odour, taking androstenone into account did not improve the efficiency obtained from sorting using skatole only. For flavour, sorting using both compounds was more efficient than sorting using skatole only. Sorting out 15% of the entire males, on the basis of skatole only, would result in a difference in the proportion of dissatisfied consumers of 4.2% (odour) or 2.0% (flavour) between entire male and gilt pork. The results of the last part of the simulation study demonstrated that decreasing skatole in entire male pig populations, to levels as low as 0.10 ppm, would still result in a difference in the proportion of dissatisfied consumers of 3.2% (odour) or 1.6% (flavour). To reduce this difference further, the levels of both compounds would have to be reduced still further. The lowest difference that can be achieved is 2.3% (odour) or 0.4% (flavour). The conclusions of the present study may differ according to whether immediate commercial applications or long-term goals are considered. On the basis of the skatole and androstenone levels currently observed in entire male pig populations, sorting out procedures based on skatole is the easiest way to rapidly achieve a significant decrease in consumer dissatisfaction with entire male pork. In most countries, however, this will not be sufficient to obtain the same level of acceptability as with gilts. In the long term, a sharp reduction in both skatole and androstenone would have to be achieved in entire male pig populations to obtain low differences in acceptability between entire male and gilt pork.     

An international study on the importance of androstenone and skatole for boar taint: III. Consumer survey in seven European countries

There has long been debate over the relative importance for consumer acceptability of androstenone and skatole. The objective of this study was to investigate consumer reaction to pig meat of varying levels of androstenone and skatole in seven member states of the European Union. Over 4000 entire male pigs (and 233 gilts as a control) were produced in six European countries, and a sub-sample of 420 were selected to represent a range of androstenone and skatole levels. Loin samples from these pigs were distributed to the seven participating countries. Samples were prepared and cooked according to standardised procedures in each of the countries and presented to pork consumers. Each consumer rated samples from five pigs for liking of flavour and liking of odour. Although there were significant differences between country panels in their liking of meat from entire males generally, there was a greater degree of dislike as both androstenone and skatole increased. This reaction was stronger for skatole than androstenone and consumers reacted more negatively in terms of odour than flavour.