Infertility and embryonic mortality are economically important for the commercial broiler industry because they are components of hatchability. Embryonic mortality in chickens is not uniformly distributed over the course of incubation; two phases of embryonic mortality are characteristic of chicken development. The objective of this paper was to develop a mathematical model to assess infertility and to characterize the distribution over time of embryonic mortality in chickens. A model was constructed based on evidence in the literature for multiple phases of embryonic mortality before and during incubation. A multiphasic model, with two phases, included parameters for the proportion of eggs that were infertile and the proportion that were fertile but the embryo died before or during incubation. For those eggs that were fertile but the embryo died, the model included the proportion of embryonic mortality during each phase, day of peak mortality, and duration of phase. Data on embryonic mortality for white Cornish chickens were used to illustrate the multiphasic model. Model parameters could be estimated easily and interpreted with clear biological meaning. Estimates of parameters, in general, were reasonably precise and consistent with the literature. With multiphasic analysis, one can assess infertility and characterize the distribution of embryonic mortality in chickens, which can lead to a useful understanding of management and genetic aspects of these components of hatchability.

No abstract

Probabilistic two-phase flow map pressure drop and void fraction models are developed for 6-port microchannels in order to provide a more accurate and common means of predicting void fraction and pressure drop.The models are developed for R134a, R410A, and air-water in 6-port microchannels at 10 o C saturation temperatures, qualities from 0 to 1, and mass fluxes varying from 50 to 300kg/m 2 -s. The probabilistic flow map models developed are found to accurately predict void fraction and pressure drop for the entire quality range and for all three fluids.

No abstract

No abstract