Computational fluid dynamics studies on pasteurisation of canned milk

Pasteurisation is a vital unit operation to inactivate the spoilage organisms and enzymes present in the milk. Computational fluid dynamics (CFD) modelling can be used as a tool to determine the temperature distribution pattern inside canned milk during thermal processing. In this study, a CFD model was developed for the pasteurisation process of canned milk at 74°C and 85°C and validated with the experimental measurements. Moreover, the effect of can rotation (5, 50 and 100 rpm) on processing time and pasteurisation value was investigated. This study predicted rotation of can with 5 rpm was more effective than stationary positioned can during pasteurisation.     

ACCOUNTING FOR HUMAN ACTIVITY THROUGH PHYSICS

Accounting for human activity through physics does not require anything more than a switch of mind. Objectivity needs first to be recognized as an epistemological principle that should mostly be ignored when modeling human activity, lest it is decided that methods from physics should not apply to man out of principle. Second, it needs to be understood that two dimensions of human activity are specific to coordinating behavior and should be regarded in earnest as being of a physical nature. The notion of field is appropriate when referring to both language and the economy. Language needs to be analyzed as a field allowing “action at distance”; the way it provides the economy with its structuring process needs to be fully acknowledged and explained.     

VISCOELASTIC BEHAVIOR OF FRIED POTATO CRUST*

A restructured potato model system was fried for 5, 10 or 15 min at 170, 180, or 190C and tested in a dynamic mechanical analyzer. Stress relaxation phenomena was described by a two‐element Maxwell model with a parallel spring. The viscoelastic behavior of the crust resulted from its porous structure of open and closed foam cells embedded in oil. Relaxation of stress in the fried crust was a result of slippage of the dispersed oil through the crust and from rearrangements of the air cells. Elastic modulus of the fried crust increased for higher frying times and temperatures and were the most significant elements in distinguishing between samples.     

等离子体浸没离子注入及表面强化工艺的进展

等离子体浸没离子注入 (PIII)消除了传统束线离子注入 (IBII)固有的视线限制 ,是一种更适合于处理复杂形状工件的手段 .近十年来 ,PIII及其工业应用在国内外得到了迅速发展 .然而 ,随着PIII的研究与开发的深入 ,发现仍有若干重要的物理与技术问题 ,诸如浅的注入层、离子注入不均匀性、气体 (氮 )等离子体的有限应用范围等等 ,阻碍了PIII工业应用的发展 .目前 ,这些问题已成为国内外学者关注的焦点 .我实验室近年来在注入过程鞘层动力学的计算机理论模拟、离子注入剂量不均匀性改善、圆筒内表面注入研究、新型长射程阴极弧金属等离子体源研制、气体及金属等离子体的综合性表面改性工艺研究、以及低能高温PIII新工艺研究等方面进行了研究工作 .     

Effect of Yttrium Pre-Implantation on Implantation Behavior of Ti-6Al-4V Alloy in Nitrogen Plasma Immersion Ion Implantation

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Growth and dry matter partitioning of Pinot Noir (Vitis vinifera L.) in relation to leaf area and crop load

Treatments varying source:sink ratio (leaf number per vine in relation to crop load) on container-grown Pinot Noir grapevines produced differences in vine growth and dry matter accumulation and partitioning. Vines with (+) and those without (-) fruit were subject to a range of leaf removal treatments. All treatments retained leaves at nodes 1–4 from the shoot base and then had: 100% (control); 66%; 33%; or 0% leaves retained from node 5 to the apex of the shoot. Leaf removal was done as leaves appeared. Leaf removal reduced vine weight. The presence of crop and the number of leaves influenced nodes per shoot and dry weight of the shoots. Removal of leaves did not influence shoot length although un cropped vines were larger in all of the above categories. Removal of either leaves or crop had an impact on leaf number, area per vine, area per leaf and leaf dry weight.'crop' vines carried fewer, and smaller leaves then the 'crop' vines. Carbon partitioning between above ground vegetative organs and roots followed the same relationship, regardless of harvest date, crop status or defoliation treatment. The 'crop 33% leaf retained' vines compensated for leaf removal by increasing their leaf size and dry weight over the '66% leaf retained' and the control.     

ETHYLENE CAPSULE PROMOTES EARLY RIPENING OF 'd'ANJOU' PEARS PACKED IN MODIFIED ATMOSPHERE BAGS

‘d'Anjou’ pears (Pyrus communis, L.) harvested commercially with flesh firmness of 64.5 N were incapable of ripening normally at 20C within 60 days of air storage at ‐1C (denoted as “under‐chilled” fruits). When under‐chilled ‘d'Anjou’ fruits (8 fruits, total fruit weight of 1.8 kg) were packed in a 3.8‐liter perforated bag inserted with an ethylene capsule, fruit would ripen normally at 20C. The ethylene concentration in the packed bag maintained no less than 100 ppm after 4 days at 20C, and declined to about 25 ppm on day 7. Regardless of the storage length, ripened fruit induced by the ethylene capsule developed high buttery and juicy texture. If ‘d’ Anjou’ fruit had been stored at ‐1C for less than 30 days, ripened fruit lacked high flavor quality. Flavor quality of ripened fruit improved rapidly when the fruit had been stored for longer than 30 days.     

Abrasive Surface Deformation of Sapphire

The depth of slip and the size of deformation twins introduced into sapphire by abrasive grinding depend on surface orientation. Enhanced depths of slip minimize surface chipping and striations, and grinding can result in basal slip depths of 30 μm and twins 75 μm in size. Basal twins in nonbasal surfaces are largest for single-point diamond abrasion directions parallel to a 〈1100〉 basal twin shear direction, whereas optically detectable rhombohedral twins are produced only in 30° and 60° surfaces.