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61.
Josep Serra Bonvehi & Francesc Ventura Coll 《International Journal of Food Science & Technology》2009,44(3):456-466
The possibilities of detecting hazelnut paste adulterated with refined and non-refined vegetable oils have been studied. Research was focussed mainly on peanut, high oleic-acid sunflower, corn and soybean oils which have a similar composition to hazelnut oil. The analytical procedures to detect fatty acid (FA), triacylglycerol (TAG) and tocopherol profiles as indicators of adulteration were determined. The better indicators experimentally determined were seven FA (palmitic, stearic, linoleic, linolenic, arachidonic, behenic and lignoceric acids) and different TAG with three unsaturated FA (the code letters used for FA are: P = C16:0 ; S = C18:0 ; O = C18:1 ; L = C18:2;; Ln = C18:3 ) (LLLn , LLL and OOO), two unsaturated FA (POL, PLL and SOO), and one unsaturated FA (PPL). As expected, when refined vegetable oils were added to hazelnut paste, the increment of stigmasta-3,5-diene allowed detection at levels of 2% oil added. Limits of detection were measured using standard and adulterated hazelnut with different amounts of non-refined vegetable oils added (5%, 10%, 20% and 30%). The distribution of tocopherols and tocotrienols is highly useful, except in the case of added sunflower oil. The differences between the experimental and theoretical values of the TAG with equivalent carbon number (ΔECN) of 42 does not improve the detection limit of hazelnut paste adulterated with peanut or sunflower oils. Similarly, tocopherols usually added to refined vegetable oils as an antioxidant were also determined. 相似文献
62.
The theoretical foundations of quantitative image analysis and its implementation in the Leitz T.A.S. have been discussed in the preceeding paper [4]. Especially the Mathematical Morphology and its recent developments have been pointed out. Sequential image transformations are a new approach of morphological analysis. Elementary transform steps, which are hardwired in the device, performed in specific sequences, which are implemented as macroinstructions in the programming language have proven to be a very useful tool in image analysis. A specific sequence of elementary steps will be referred to as morphological function. This new approach will be illustrated by four general examples: analysis of fibers, computing the number of edges for metallic grains, separation of overlapping cells, analysis of minerals which occur free and locked to another one. 相似文献
63.
64.
Contends that both the interpretation of an effect size and the actual estimation of a coefficient of determination are partially theory-dependent. Two theoretical models for the variables cases are considered. In a variety of circumstances where the square of the correlation is used, the required assumptions are not tenable. In the alternate model, the absolute value of the correlation provides a coefficient of determination. The correlation coefficient is recommended for use as an effect-size indicator, because evaluating effect size in terms of variance accounted for may lead to interpretations that grossly underestimate the magnitude of a relation. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Let T be a minimal generating subset of a group G . Let Γ be the Cayley graph defined on G by . Let d
2
be the minimal cardinality of the boundary of two points. We show that, for |S|>4 , every cutset with cardinality less than d
2
must isolate a single vertex.
Received April 1996, and in final form February 1999. 相似文献
66.
67.
68.
Michael Serra 《Nexus Network Journal》2002,4(2):113-115
Michael Serra describes a class project for constructing arches and examining their properties. The objective was for students
to review and apply the properties of isosceles triangles, trapezoids, regular polygons, and of interior and exterior angle
sums. They were to practice communicating mathematically and modeling in two and three dimensions. It is a fun two-day activity
of hands-on mathematics and problem solving. 相似文献
69.
E. Serra A. Calza Bini G. Cosoli L. Pilloni 《Journal of the American Ceramic Society》2005,88(1):15-18
The aim of this work is to measure the hydrogen transport and solubility parameters in the commercial alumina. Measurements are conducted using a time-dependent permeation method over the temperature range 1273–1673 K with hydrogen driving pressures in the range 104 –105 Pa (100–1000 mbar). A half-power pressure dependence (diffusion-limited permeation) of the permeation flux for alumina is observed. The Arrhenius expressions for the hydrogen permeability, diffusivity, and Sieverts' constant values obtained from a fitting to the whole temperature range are as follows:
70.
Effect of blend ratio and elongation flow on the morphology and properties of epoxy resin‐poly(trimethylene terephthalate) blends 下载免费PDF全文
C. Sarath Chandran Rene Muller M. Bouquey C. Serra S. Thomas 《Polymer Engineering and Science》2015,55(7):1679-1688
The effect of processing conditions on the morphology of polymer blends is a topic of tremendous practical interest especially for thermoset–thermoplastic blends. The effect of blend ratio and the nature of the flow field (shear flow vs. elongation flow) on the morphology is followed here using blends of diglycidyl ether of bisphenol A (DGEBA)‐poly(trimethylene terephthalate) (PTT). Morphology of the blends prepared by the conventional melt mixing technique is compared with that prepared by using an elongation mixer (RMX device invented by Muller et al.). The blends prepared by the elongation mixer showed excellent transparency and higher storage modulus at room temperature than the conventional mixer. In the case of samples prepared by the RMX device Tg of the epoxy phase has been shifted to lower temperatures indicating a molecular level mixing between PTT and DGEBA. However the conventional melt mixed samples showed only a marginal shift in Tg to low temperatures indicating that the system is not as miscible as that prepared by the RMX device. The use of RMX device for thermoset–thermoplastic blends is novel and no work has been reported in this relation. The properties of the blends were strongly affected by the composition and the crystallization of the semicrystalline PTT phase. POLYM. ENG. SCI., 55:1679–1688, 2015. © 2014 Society of Plastics Engineers 相似文献