Film thickness measurement with an ultrasonic transducer

A technique for measuring condensate film thickness using an ultrasonic transducer is described. In the experiment, the condensate film thickness with R-113 and FC-72 (a fluorinert compound developed by the 3M Company) condensing on the horizontal lower surface of a rectangular duct was measured at several locations. From the measured values a power law relation between the condensate film thickness and the axial distance from the leading edge of the condensing surface was derived by regression analysis. Assuming a linear temperature profile in the condensate film, local and average heat transfer coefficients were computed from the condensate film thickness. The average heat transfer coefficients were compared with the values obtained by measuring the heat transfer rate to the coolant. The two values were within ±12% of each other. As yet there is no satisfactory analytical model to predict the local heat transfer coefficient even in the annular condensation regime. One of the main difficulties in modeling the condensation is the lack of a suitable model to predict the interfacial shear stress. With the measurement of the film thickness it is possible to determine the interfacial shear stress. It is hoped that the shear stresses so determined will lead to the development of a satisfactory model for interfacial shear stress with condensation.     

Atmospheric Plasma Sterilization and Deodorization of Dielectric Surfaces

A method is presented for rapid and uniform sterilization and deodorization of dielectric surfaces. The technology is applicable to the inside surface of PET or glass bottles, polymer caps, plastic tubes, etc. The treatment is based on a pulsed RF discharge in air at atmospheric pressure (eventually with addition of argon) creating a nonequilibrium plasma on the treated surface. The plasma effectively destroys microorganisms in vegetative or sporulent form. It also slightly etches the polymeric material, removing some atomic layers and, thereby, cleaning it from aromatic organic components (deodorization). The process is short: PET bottles 1.5 L, in particular, can be treated in about 20 msec. The results of surface analysis and microbiological, chromatography, and spectroscopy tests are discussed. A device has been developed and integrated into an industrial-filling machine for online sterilization and deodorization of the inside surface of PET bottles before filling, and for sterilization of caps and bottle necks before seaming. It allows cold asceptic filling at a rate of 36,000 bottles per hour.     

Helium atom inside boxes with paraboloidal walls

The ground-state energy of the helium atom inside boxes with paraboloidal walls, with the nucleus at the common focus, is calculated variationally. The variational functions are products of geometry-adapted hydrogenic functions, and the interelectronic Coulomb repulsion is represented through its harmonic expansion in parabolic coordinates. The energy, pressure, quadrupole moment, and polarizability of the atom are determined as functions of the positions of the walls for symmetrical boxes. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 66 : 123–130, 1998     

爆炸荷载下沉箱重力式码头模型毁伤效应

在野外条件下开展了不同爆炸荷载条件下沉箱重力式码头模型毁伤效应实验,得到了沉箱重力式码头模型在1 kg TNT当量空中爆炸、水下爆炸以及结构内部爆炸后的毁伤模式,并针对不同毁伤模式给出了相应的抢修建议。实验结果表明：空中爆炸荷载下码头仅面板局部破坏形成爆坑;水下爆炸荷载下码头迎爆面及相近区域形成大量裂缝;结构内部爆炸荷载下码头仓格大变形破坏且中间面板被掀飞;从横向对比来看,在相同爆炸当量下空中爆炸荷载下码头毁伤程度最小,结构内部爆炸荷载下码头毁伤程度最大。

     

Two‐electron atomic systems confined within spheroidal boxes

The direct variational method is used to estimate some interesting physical properties of the He atom and the Li⁺ ion confined within impenetrable spheroidal boxes. A comparative investigation of the ground‐state energy, pressure, polarizability, dipole, and quadrupole moments with those of the He atom inside boxes with paraboloidal walls is made. The overall results show a similar qualitative behavior. However, for Li⁺ there are quantitative differences on such properties due to its major nuclear charge, as expected. The trial wave function is constructed as a product of two hydrogenic wave functions adapted to the geometry of the confining boxes. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 509–515, 2000     

Factorization theory of root closed monoids of small rank

In this note, we investigate ideal and factorization-theoretic properties of some root closed cancellative commutative monoids of rank at most two.     

半无限弹性空间域内点加振格林函数的计算

本文给出了满足全部自由面边界条件的半无限弹性空间域内点加振的Ｇｒｅｅｎ函数，利用变形的Ｈａｎｋｅｌ函数，在复数域内进行无限积分的有限化，从而使Ｇｒｅｅｎ函数的计算变得比较简单和方便。     

Detecting dark energy in long baseline neutrino oscillations

In this paper, we discuss a possibility of studying properties of dark energy in long baseline neutrino oscillation experiments. We consider two types of models of neutrino dark energy. For one type of models the scalar field is taken to be quintessence-like and for the other phantom-like. In these models the scalar fields couple to the neutrinos to give rise to spatially varying neutrino masses. We will show that the two types of models predict different behaviors of the spatial variation of the neutrino masses inside the Earth and consequently result in different signals in long baseline neutrino oscillation experiments.     

非定常流函数涡量方程的一种数值解法的研究

对非定常流函数涡量方程的数值求解方法进行了改进,其中流函数一阶导数即速度项采用四阶精度的Hermitian公式,对流项由一般二阶精度的中心差分提高到四阶精度离散差分,包含温度方程在内的离散方程组采用ADI迭代方法求得定常解．以无内热体及有一内热体的封闭方腔内自然对流为例,进行了不同瑞利数（Ra）条件下的数值研究．结果表明,该方法推导简单,求解精度高且计算稳定,适用于封闭腔内高瑞利数复杂混合对流的数值模拟．