Large deflection beam transport with screened Rutherford scattering

We consider the steady-state monoenergetic searchlight problem involving screened Rutherford scattering. A recently reported formalism is modified to improve upon its accuracy for large beam deflections. Comparisons with benchmark Monte Carlo calculations demonstrate the improved accuracy of this modified formalism.     

Developing utility functions for environmental decision making

The selection of a technology for the cleanup of a contaminated site is complicated by the involvement of multiple stakeholders with conflicting objectives. Multi-attribute decision analysis can be employed to assess the impact of the alternative technologies on a number of performance measures and to rank these alternatives according to the preferences of each stakeholder. In this paper, we present an approach to constructing the utility functions that decision analysis requires using stakeholder input. The proposed approach is based on the Analytic Hierarchy Process and accounts for linguistic imprecision in the stakeholder assessments. The experience from a real case study is reported and discussed.     

Pollution effects on stone benches of the Eagle Warriors Precinct at the Major Temple, Mexico City

During Major Temple archaeological site excavations in Downtown Mexico City, the precinct of one of the most important Mexica military caste, the Eagle Warriors, was discovered. The ceremonial enclosure is composed of three rooms surrounded by paintings on 11 stone benches placed against the walls. Nowadays, these paintings and the stones present the effects of different deterioration processes produced by the underground water level, high humidity, and the presence of soil, water, and air pollutants. Ion beam analysis of samples from the benches and wall paintings was performed using PIXE and RBS techniques. Using enrichment factors of elements relative to iron concentrations, possible contamination by sulfur and chlorine salts was found, as well as airborne zinc scavenged by rain.     

Heat transfer during boiling of a liquid metal during emergency cooldown of a fast-neutron reactor

The physics of the processes, the characteristics, and the stability of different regimes, of boiling (nucleate, projectile, disperse-ring), which are observed in experiments investigating the boiling of liquid-metal coolant in a model of a fuel assembly for a fast-neutron reactor in the emergency cooldown regime with low circulation velocity, are analyzed. The experimental setup, the, methods for performing measurements, and the experimental data on the boiling of a liquid metal are described. A mathematical model of the process of boiling of a liquid-metal, coolant in a natural-circulation loop is described, and the results of test calculations for regimes with an increase in heating and with sharp pressure drop are prresented. 7 figures, 12 references. State Science Center of the Russian Federration–A. I. Leipunskii Physics and Power Engineering Institute. Translated from Atomnaya énergiya, Vol. 87, No. 5, pp. 337–342, November, 1999.     

Observation of atomic steps on single crystal surfaces by a commercial scanning electron microscope.

Atomic steps on (111) and (100) crystal surfaces of Pt were observed using a commercial scanning electron microscope (SEM) in secondary electron mode. By comparing the SEM images and those by reflection electron microscopy (REM), the observed contrast was confirmed to be that from atomic steps on crystal surfaces. The contrast mechanism is briefly discussed. One application of this imaging technique is also shown.     

弹性金属塑料瓦推力轴承的滑移问题研究

本文对流体力学的经典雷诺方程中固液界面无滑移假设对于弹性金属塑料瓦的适用性提出疑问，从理论上论证在一些表面能低的聚合物表面存在滑移的可能性，并进行对比实验，实验证明在聚四氟乙烯与润滑油的界面上存在滑移现象，发现滑移是在剪切速率和油膜厚度达到一定值才出现的，滑移速度随着转速的提高和膜厚的减小而增大。在分析以聚四氟乙烯为表面的弹性金属塑料轴瓦的润滑机理时，应当对雷诺方程进行修正，计入滑移因素的影响。     

A high shear rate, high pressure microviscometer

The development of a high shear rate, high pressure microviscometer is described. This viscometer was developed specifically to examine a highly loaded, dynamic contact generated in a small volume of fluid. The viscometer was used to examine the fluid film formed by the mechanism of elastohydrodynamic lubrication in the presence of an SAE 50 oil. A complete numerical analysis of the resulting elastohydrodynamic contact was performed.     

The effects of thermosetting and castable encapsulation methods on the metallographic preparation of ceramic thermally sprayed coatings—A technical note

Accurate microstructural analysis of thermally sprayed coatings is possible only if specimen preparation produces a surface that clearly reveals the true microstructure. Comparison of similar specimens pre-pared by different laboratories, or different personnel in the same laboratory, often shows significant dif-ferences or variations in the microstructures, producing conflicting information that lowers the confi-dence level of microstructural analysis. A study was conducted on an alumina coating and an 8 wt% yttria-stabilized zirconia coating, both sprayed on metal substrates, to evaluate the effects of two differ-ent encapsulating procedures.