Model of Water Application under Pivot Sprinkler. I: Theoretical Grounds

A model describing the application pattern produced by a single sprinkler is proposed. Based on calibrated statistical distributions and free from any ballistic consideration, this model uses a mixture of beta probability distributions in which parameters are first estimated with water application data measured in zero wind condition. Data measured in field conditions are then used to assess the wind effect on the shift of the center of gravity of the irrigated area, on the range of the sprinkler in various directions, and on the values of the beta distributions' parameters. The computation of the water application amounts at any point of the irrigated area is finally resolved in the use of a single equation, which can be easily implemented in a software package to simulate application patterns under a series of sprinklers attached to a center pivot or moving lateral irrigation machine.     

水性闪光底漆的制备与性能研究

采用水性聚丙烯酸或水性聚氨酯作为成膜基料,与水性闪光颜料、各种涂料添加剂等配制底漆。讨论了树脂和助剂的种类及其配比对颜料颗粒取向的影响。对涂膜的机械性能、闪光效果以及视觉丰满度、流平性、稳定性等的检测结果表明,漆膜具有良好的性能。     

Thermal aggregation of whey proteins in the presence of buttermilk concentrate

The objective of this study was to assess the impact of adding buttermilk concentrate to the denaturation and microparticulation process of cheese whey protein concentrate. For this purpose, the two concentrates were mixed and co-denatured (pH 4.6, 90 °C,) and homogenized. The presence of buttermilk significantly increased aggregation yield and decreased water-holding capacity of aggregates up to a buttermilk:whey protein ratio of 75:25. Modification of rheological properties suggests that denatured whey protein interacted with casein. A thiol blocker, N-ethylmaleimide, was added before heating to measure the role of disulphide bond formation in the aggregation process. Results showed that both covalent and non-covalent interactions were involved in aggregate formation. Ultrasound treatment was applied during denaturation process and was shown to influence aggregate formation. It appeared that under increased turbulence and cavitation conditions, aggregation yield was increased and water-holding capacity decreased.     

Tribological properties of fluid phase phospholipid bilayers

Our recent studies showed that solid phase phospholipid bilayers play an important role in joint lubrication mechanism. We investigate the tribological properties of fluid phase bilayers depending on various experimental parameters. Bilayers containing a fluorescent lipid with a large head-group and surfaces covered with only one bilayer poorly lubricate meaning that the slip plane during shear is located in the thin aqueous layer between the bilayers. Lubrication and resistance to normal and tangential stresses are greatly improved in buffered saline solution. Bilayers prepared by vesicle fusion method improve the tribological properties of even very rough substrates by smoothing their topographical defects.     

Microoptical elements for single mode fibre arrays free-space interconnections

The purpose of this paper is to investigate the performance of microoptics for telecommunication systems using free-space interconnects. This concerns mainly distribution or switching and routing tasks. In order to evaluate the interconnection capability of free-space microoptics, we impose severe conditions on the interconnects. These conditions correspond to the use of single mode fibre arrays at both the input and the output systems. This point is shown to become very critical when dealing with optical switches involving reconfigu-rable links. These points are illustrated by two examples : one with fixed and the other with reconfigurable interconnects but both using arrays of microoptical elements.     

Comparison of gas exchange and hemodynamic variables during 2 types of exercise tests. Cycle-ergometry and the ergometric table

The development of stress echocardiography on an ergometric table has increased the number of stress tests in the decubitus position, whereas most of the information currently available concerns stress tests in the sitting position or on the treadmill. In order to study the influence of this position of stress testing, the authors compared the results obtained in a series of 15 patients without cardiac disease (Group I) and another series of 15 coronary patients (Group II) undergoing the two types of stress testing, in the vertical position on a bicycle ergometer and in the lateral decubitus position on the ergometric table. Effort tolerance on the bicycle ergometer was significantly greater in terms of work load (202 +/- 35 vs 180 +/- 36 watts (p < 0.001) in the controls, and 120 +/- 32 vs 106 +/- 22 watts (p < 0.05) in the coronary group), of duration of effort (19 +/- 3 vs 16 +/- 3 minutes (p < 0.001) in the controls and 10 +/- 3 vs 8 +/- 2 minutes (p < 0.05) in the coronary patients), of heart rate (190 +/- 10 vs 172 +/- 21 beats/min (p < 0.005) in controls and 118 +/- 19 vs 111 +/- 14 beats/min (p < 0.05) in the coronary patients). On the other hand, blood pressure and O2 saturation tended to be greater during exercise in the decubitus position: SBP 200 +/- 23 vs 196 +/- 27 mmHg (NS) in the controls and 158 +/- 21 vs 166 +/- 23 mmHg (NS) in the coronary patients; DBP 97 +/- 10 vs 102 +/- 27 mmHg (NS) in the controls and 85 +/- 6 vs 90 +/- 10 mmHg (NS) in the coronary patients; O2 sat 96.8 +/- 1 vs 97.6 +/- 0.8% (p < 0.05) in the coronary patients. The anaerobic threshold and peak VO2 were much higher during exercise in the sitting position: oxygen consumption at the threshold 14.8 +/- 3.8 vs 12.6 +/- 2.3 ml.kg-1.min-1 (p < 0.01), peak VO2 22.2 +/- 5.9 vs 18.8 +/- 4.7 ml.kg-1.min-1 (p < 0.01) in the coronary patients. The results of this study show that the cardiovascular stimulation obtained in the decubitus position is not identical to that obtained by traditional exercise stress testing, particularly in coronary patients.     

A 4D Ray Tracing

We are going to present a survey of techniques using temporal coherence in between frames to render animation sequences with ray tracing. A new method using temporal coherence in the ray space (lightpath of rays) is proposed. The goal of this technique is to factorize intersection and illumination calculations over the frames of the sequence. An optical event springing out many times in the sequence is computed once. The method is based upon 4D intersection calculations between temporal rays and moving objects. At the end of this paper, we present measurements showing the number of rays we need not calculate with our solution. These results come from simulating the algorithm behavior through a graphic and statistic ray analyser tool.     

A simple canonical representation of rational numbers

We propose to use a simple inductive type as a basis to represent the field of rational numbers. We describe the relation between this representation of numbers and the representation as fractions of non-zero natural numbers. The usual operations of comparison, multiplication, and addition are then defined in a naive way. The whole construction is used to build a model of the set of rational numbers as an ordered archimedian field. All constructions have been modeled and verified in the Coq proof assistant.