Atlantic Salmon Average Fat Content Estimated by Near-Infrared Transmittance Spectroscopy

Near-infrared transmittance spectroscopy was used to determine the average fat content in farmed Atlantic salmon fillets with skin and scales. The fat content was 5.7–17.6% and weight range 1.0–5.4 kg. A partial least square regression including 43 salmon resulted in a multivariate prediction correlation of 0.97 and a root mean square error of cross validation of 0.75%. Regression models using 6 to 9 wavelengths in the 850–1048 nm range gave somewhat lower prediction errors than a model using 100 wavelengths. Results showed that NIR transmittance was suited to determine fat content nondestructively in whole salmon fillets with skin and scales.     

应用神经网络模型对大学毕业生就业质量的预测

目的:尝试应用BP人工神经网络模型预测大学毕业生的就业质量。方法:以476名大学毕业生为研究对象,将毕业生的各种心理特质作为预测因子,利用Clementine数据挖掘软件构建大学毕业生就业质量的BP人工神经网络模型。结果:神经网络模型的拟合精度达到99.98%,对就业质量的平均绝对预测误差值为0.083。结论:该神经网络模型可用来预测和诊断大学毕业生找到工作后的就业质量,为就业指导工作提供技术与理论依据。     

MEASUREMENT TECHNIQUES AND DATA INTERPRETATIONS FOR VALIDATING CFD MULTI PHASE REACTOR MODELS

One problem associated with the use of Computational Fluid Dynamics(CFD) in reactor modeling is the proper validation of the models. Proper validation in this context means that the physical fluid dynamic model, the mathematical implementation and the data used for validation must be consistent. The present paper addresses this issue and to provide appropriate relations between experimental method and modeling approach

A critical review of currently used measurement techniques for characterizing multiphase now systems is presented. The interpretation of the data obtained from the various techniques is discussed as well as how these data can be used for validation of various CFD model formulations

Steady state models can be validated using time averaged data, making sure that the averaging time for the experimental data is long enough so that low frequency periodic oscillations also are evened out. If homogeneous systems are considered, then a volume average approach may be used for modeling, If the system cannot be considered homogeneous and steady, as is the most common case, then a dynamic ensemble averaging technique should be preferred. The validation of such models must be done with methods fast enough to resolve periodic fluctuating structures of interest. These methods are cumbersome and tedious to operate and the ergodic hypothesis may be invoked enabling the use of volume or time averaged data for the validation of ensemble averaged models.     

THE USE OF CO2 IN PACKAGING OF FRESH RED MEATS AND ITS EFFECT ON CHEMICAL QUALITY CHANGES IN THE MEAT: A REVIEW

The antimicrobial effect of carbon dioxide (CO₂) is well documented but comparison of the large number of often contradictory studies investigating the effect of CO₂ on chemical quality changes is lacking. The amount of absorbed CO₂ varies from 0 - 1.79 L CO₂/kg meat depending on the applied packaging and storage conditions, which clearly demonstrates the necessity of optimizing these conditions with respect to the required amount of CO₂. Absorption of large amounts of CO₂ in meat tissue can cause a minor decrease in pH due to the dissociation of the produced carbonic acid to bicarbonate and hydrogen ions. A decrease in pH might affect other chemical quality parameters but this is not observed to be the case in the reviewed studies and general detrimental effects of CO₂ cannot be found for color, weight loss or lipid oxidation. However, elevated CO₂ levels can cause pore formation in cooked meat.