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21.
Oil-in-water emulsions stabilized with nonionic emulsifiers change to water-in-oil emulsions as the temperature rises when the hydrophilic and lipophilic properties of the mixed emulsifier are just balanced. Preparation above the phase inversion temperature followed by rapid cooling yields emulsions that exhibit very fine droplet size and extreme long-term stability. Cosmetic emulsions were prepared by this phase inversion temperature (PIT) method using typical raw materials such as polar oils, e.g. decyl oleate, 2-octyl dodecanol or isopropyl myristate, and nonionic emulsifiers, e.g. ceteareth-12 or polyoxyethylene eicosyl/docosyl ether combined with cetostearyl alcohol as a co-emulsifier. The phase inversion temperature was measured as a function of the oil polarity and the concentration of mixed emulsifier. The relationship between phase inversion temperature, droplet size and emulsion stability was investigated. In addition, self-bodying agents such as cetostearyl alcohol or monoglycerides were added to these thin, fine disperse emulsions to adjust the consistency. The influence of these ingredients on phase inversion temperature, droplet size, yield value and emulsion stability was studied. 相似文献
22.
CJ Laruelle GB Brueren SM Ernst ET Bal GE Mast MJ Suttorp A Brutel de la Rivière TH Plokker 《Canadian Metallurgical Quarterly》1998,79(2):148-152
The effect of bone plug length and Kurosaka screw (DePuy, Warsaw, IN) diameter on graft holding strength of the bone-tendon-bone construct was determined. Random length porcine bone plugs were assigned to fixation with 7 or 9 mm Kurosaka screws. Peak load to failure was determined. There was a significant decrease in peak load to failure of the 5-mm long bone plugs compared with longer bone plugs. No difference was found between longer lengths of bone plug in either the 7- or 9-mm screw diameter groups. The 9-mm diameter screws significantly increased peak load to failure for both 1- and 2-cm bone plug lengths. 相似文献
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LUC SARRAZIN THéRèSE SCHEMBRI PIERRE REBOUILLON 《The International journal of environmental studies》2013,70(4):413-425
A selective method for determining polycyclic aromatic hydrocarbons (PAHs) in sediments using solid‐phase extraction and RP‐HPLC with fluorescence and UV detection is described. The complete analytical method is used to surface sediments from the creek of Cortiou (France). Sewage from the urban area of Marseille is delivered to the creek. PAH levels in sediments (µg/g) range between 2.251 µg/g (for the benzo(a)anthracene) and 0.001 µg/g. The flux of pollution provided by the outfall is preferentially oriented from East to West by the Liguro‐Provenalcal current. The significant values are mainly confined on a perimeter of 2 km around the outfall. The phenanthrene/anthracene and fluoranthene/pyrene ratios indicate pyrolytic and petrogenic contamination. The particulate size observations concerning the sediments show that oxygenated sandy zones, where eliminating mechanisms (desorption, biodegradation) take place, are mainly located on the Chêvres plateau and around Jarre, Plane and Riou Islands. 相似文献
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FRANÇOIS DES ROSIERS MARIUS THÉRIAULT YAN KESTENS PAUL VILLENEUVE 《Housing Studies》2007,22(6):945-964
This paper investigates the effect of environmental features on house values while focusing on the interactions between landscaping attributes and home buyers' profile. The originality of this study rests on the assumption that, while neighbourhood characteristics translate into distinct sub-markets and primarily set the structure of house prices, individual home buyers' preferences, under specific market conditions, also affect values. The study benefits from two distinct, although related data sets on the single-family segment of Quebec City's housing market: while landscaping features were obtained via an extensive field survey of houses sold between 1993 and 2000, a detailed phone survey of related homeowners' family status, age and income profiles is being conducted since 2000. Findings suggest that household profile and structure do shape landscaping preferences and that utility patterns of homeowners may be best understood by looking at interactions between the two sets of variables. Considering that population aging is a major issue for economic and social planners, such a conclusion should be accounted for in housing policy design. 相似文献
27.
J. Friend 《International Transactions in Operational Research》1995,2(3):225-232
A case is developed for recognizing the distinctive contribution which OR scientists can make to the understanding and support of processes of developmental decision making, conceived as processes in which people work progressively (and often collaboratively) to address ever-changing clusters of decisions which are richly connected and non-recurrent. The argument is illustrated through reference to the evolution over the last three decades of the strategic choice approach to planning under uncertainty, as one example of an OR methodology that can be located within an emergent generic field of developmental decision science. It is argued that this perspective can complement that of systems theory in ways which are important not only for the future of OR, but also for the future development of human capacities to address daunting societal problems. 相似文献
28.
A correlation is presented for the extensive series of thermal conductivity measurements of binary methane-ethane mixtures. The composition dependences of the thermal conductivity in the dilute-gas region, dense-gas and liquid region, and critical region are discussed. The average absolute percentage deviation of the thermal conductivity surface as a function of temperature, density, and composition, from the experimental data, is 1.60%. 相似文献
29.
Conjugated polymers such as polyacetylene are semiconductors, and can be chemically doped to give very high values of conductivity (up to 150 000 S cm–1). The semiconducting properties are due to delocalization of the electron system formed along the polymer chain, and this general class of materials shows many desirable semiconductor properties for electrical and optical applications. There are considerable challenges to find synthetic routes to allow processing of the polymer to the forms required for applications, and many of the recent important advances in the field are due to improvements in this area. 相似文献