5,223 research outputs found

    Expansion of the whole wheat flour extrusion

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    A new model framework is proposed to describe the expansion of extrudates with extruder operating conditions based on dimensional analysis principle. The Buckingham pi dimensional analysis method is applied to form the basic structure of the model from extrusion process operational parameters. Using the Central Composite Design (CCD) method, whole wheat flour was processed in a twin-screw extruder with 16 trials. The proposed model can well correlate the expansion of the 16 trials using 3 regression parameters. The average deviation of the correlation is 5.9%

    A new engineering method for understanding extrusion cooking process

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    A new engineering method is proposed to understand extrudate expansion and extrusion operation parameters for starch based food extrusion cooking process through dimensional analysis principle, i.e. Buckingham pi theorem. Three dimensionless groups, i.e. pump efficiency, water content and temperature, are suggested to describe the extrudate expansion. Using the three dimensionless groups, an equation is derived to express the extrudate expansion. The model has been used to correlate the experimental data for whole wheat flour and fish feed extrusion cooking. The average deviations of the correlation are respectively 5.9% and 9% for the whole wheat flour and the fish feed extrusion. An alternative 4-coefficient equation is also suggested from the 3 dimensionless groups. The average deviations of the alternative equation are respectively 5.8% and 2.5% in correlation with the same set of experimental data

    Modelling extrudate expansion in a twin-screw food extrusion cooking process through dimensional analysis methodology

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    A new phenomenological modelling framework is proposed to correlate the extrudate expansion and extrusion process parameters through dimensional analysis methodology. As dimensional analysis is independent of system or equipment structure, the proposed equation may provide a general expression for the extrudate expansion behaviours and process operation conditions. This work includes extrusion cooking trials, model development and data analysis

    The covering radius problem for sets of perfect matchings

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    Consider the family of all perfect matchings of the complete graph K2nK_{2n} with 2n2n vertices. Given any collection M\mathcal M of perfect matchings of size ss, there exists a maximum number f(n,x)f(n,x) such that if sf(n,x)s\leq f(n,x), then there exists a perfect matching that agrees with each perfect matching in M\mathcal M in at most x1x-1 edges. We use probabilistic arguments to give several lower bounds for f(n,x)f(n,x). We also apply the Lov\'asz local lemma to find a function g(n,x)g(n,x) such that if each edge appears at most g(n,x)g(n, x) times then there exists a perfect matching that agrees with each perfect matching in M\mathcal M in at most x1x-1 edges. This is an analogue of an extremal result vis-\'a-vis the covering radius of sets of permutations, which was studied by Cameron and Wanless (cf. \cite{cameron}), and Keevash and Ku (cf. \cite{ku}). We also conclude with a conjecture of a more general problem in hypergraph matchings.Comment: 10 page

    More TORC for the gluconeogenic engine

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    Hepatic gluconeogenesis plays a key role in the maintenance of glucose homeostasis. The hormone glucagon stimulates this process, whereas insulin and adiponectin are inhibitory. In a recent report, Koo et al identify the transcriptional regulator TORC2 (Transducer of Regulated CREB activity 2) as a pivotal component of the gluconeogenic program. 1 Both insulin and AMPK increase the phosphorylation of TORC2, while glucagon suppresses it. This in turn regulates the nuclear/cytoplasmic shuttling of TORC2 and its ability to transactivate gluconeogenic genes. Thus, TORC2 might serve as a gluconeogenic “molecular switch” that senses hormones and cellular energy status. BioEssays 28: 231–234, 2006. © 2006 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49523/1/20375_ftp.pd
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