GRID COMPUTING AND DISCLOSURE CONTROL

A grid is a distributed network of computers that can be used as a single information and computational resource for multiple datasets and sources. One of the key challenges of grid computing is that information in different datasets and different types of data such as text and image are likely to have different levels of sensitivity, disclosure risk and terms of use. This paper provides an overview of the development of grid computing and an examination of the disclosure risks poses. The research, funded under the Economic and Social Research Council's (ESRC) e-Social Science Programme, specifically examined the development of grid computing in social science and the work of the e-Social Science grid pilot projects. The paper concludes that while a number of innovative grid enablement projects are in development there has only been a limited assessment of the additional disclosure risks grid computing may pose. The incorporation of effective confidentiality and disclosure control systems will be central in encouraging data holders to share their data and computational resources.     

Variations occurring in the light scattering film test

Variation in the results obtained in the Light Scattering Film (LSF) Test, also referred to as the Fog Test, presents problems both for the investigator as well as the formulator. The results are often confusing (two similar formulas will produce widely different results) and seldom repeatable. In the Fog Test high fog values are desired because high fog values mean less fog. The results of this study demonstrate that the standard deviation for multiple tests on the same sample decreases with increasing fog value. The values obtained when little LSF is produced (high fog values) vary only slightly while the values obtained for heavy LSF (low fog values) fluctuate as much as 30 points. Several explanations are offered for this lack of repeatability, but they condense down to the fact that all of the variables which affect the results are not presently controlled. The tests cited in this report were conducted using Di-2-ethylhexyl phthalate, Diisodecyl phthalate, and Di-(1-heptyl, nonyl, undecyl) phthalate as neat plasticizers from commerical suppliers. DOP was used because it is currently used by the SAE as an industry standard. The remaining two plasticizers were used because they are typically used in flexible PVC for automotive interiors. Results of this study confirm that the variations encountered in the LSF Test are inherent in the test itself and not due to the material being evaluated. Fluctuations which occur around a given LSF value occur to the same degree irrespective of the material producing the light scattering film.     

微孔二氧化硅负载络合铂催化1-辛烯硅氢加成反应

以微孔二氧化硅为载体,制备了微孔二氧化硅负载的铂胶体催化剂,并进行了表征。在密闭反应器中将催化剂用于催化1-辛烯与甲基氢二氯硅烷硅氢加成反应,结果显示该催化剂在常温常压下有很高的催化活性和重复实用性。无溶剂、40℃温度下反应10 h,甲基氢二氯硅烷的转化率可达99.11%,区域选择性β-加成产物100%。催化剂性能稳定,回收使用25次无明显失活。     

Optical properties of carbonized preoxidized vitrinites

The optical properties at 546 nm of three vitrinites (daf carbon contents 82.5, 88.0 and 93.1%) have been examined after pre-oxidation for 14 days at 105 °C and carbonization at intervals of 50 °C within the temperature range 300–800 °C. In general, pre-oxidation prior to carbonization produces only relatively small changes in the trends of optical parameters with temperature that were observed for the same vitrinites when carbonized fresh; the properties of the anthracitic vitrinite displayed little modification. Reflectivities of carbonized pre-oxidized vitrinites of bituminous rank are higher than those for the equivalent fresh vitrinites up to 500 °C, supporting the suggestion that oxidation raises aromaticity and consequently the reflectivity. The most noticeable optical difference occurs with the bituminous-rank vitrinites, in the variation with carbonization temperature of their refractive-index curves, which parallel the behaviour of the L_c curves of X-ray diffraction studies. In particular, the refractive-index track for the carbonized pre-oxidized vitrinite of coking-coal rank no longer shows the same marked contrast to the refractive-index tracks of vitrinites of higher and lower rank, as it does at temperatures above 600 °C when carbonized fresh. The absorptive indices follow similar trends to the reflectivities for all the chars.     

LTCC Fabrication for a Leaf Spring Vertical Actuator

Ceramic laminate systems (LTCC) provide an alternative to silicon for three-dimensional actuator fabrication. The results of a LTCC vertical actuator study are presented. Based on a multi-fold leaf spring design, appearing as a series of cantilevers oriented in opposite directions, vertical motion is achieved via electrostatic actuation to compress and release the structure. Single and multi-fold proof-of-concept devices were modeled, fabricated, and tested. The device can vertically actuate 10-μm per fold under an applied voltage of 35 V. The actuation per fold may be controlled at 0.33-μm/V, over the range of 5–35 V.     

The effect of relative humidity on adsorption of sulphur dioxide on to metal surfaces

Previous studies of the influence of relative humidity on ³⁵SO₂ adsorption on to iron and zinc surfaces are supplemented by using a continuous flow exposure method. This gives results which agree closely with those from the previously reported interrupted-flow method for most areas studied. It is found that sample preparation before exposure has a considerable effect on the results achieved.A desorption process from the zinc-zinc oxide-SO₂ surface system has been found, with a pseudo-first order half-life of the reaction of approx 7·2 ks. Desorption from some iron samples was also observed, but could not be quantified.     

An investigation of the dynamic absorber effect in high-speed machining

In order to achieve increased material removal rates in high-speed machining, stable cutting conditions may be selected based on the system dynamics. In this paper, we apply Receptance Coupling Substructure Analysis to develop models for a stacked flexure setup and a spindle-holder–tool assembly in order to investigate the ‘dynamic absorber effect’ that can improve the system dynamic stiffness and, therefore, increase the critical stability limit in machining. The dynamic absorber effect results from an interaction between modes associated with the individual substructures, e.g. the spindle-holder and tool in the spindle-holder–tool assembly. Experimental results are provided for: (1) a two degree-of-freedom stacked flexure assembly; and (2) a machining center. These results can be considered in the selection of assembly parameters, such as tool overhang length, as well as in the design of spindle, holder, and tool components in order to improve dynamic stiffness and, consequently, material removal rates.     

Applicability of sheep and pig models for cancellous bone in human vertebral bodies

The mineral content of cancellous bone from sheep and pig vertebral bodies was determined by ashing at 800 degrees C. The results were compared with published results for human vertebral cancellous bone. The results for sheep (0.37 +/- 0.06 gcm(-3), mean +/- standard deviation) were not significantly different (p = 0.127) to those from pigs (0.33 +/- 0.03 gcm(-3)). The results from both species were significantly higher (p < 0.001) than those from human bones (0.15 +/- 0.02 gcm(-3)). This means that cancellous bone from sheep and pig vertebral bodies is not a good model for corresponding human bone. However, sheep and pig bone are useful, for example, for providing stringent tests of cutting instruments to be used in human spinal surgery.     

ROTATING TOOL POINT FREQUENCY RESPONSE PREDICTION USING RCSA

This article describes the prediction of rotating tool point frequency response functions using receptance coupling substructure analysis (RCSA). In this approach, the at-speed spindle-machine dynamics are identified by impact tests of a rotating cylindrical standard artifact. After removing the portion of the artifact beyond the holder flange in simulation, models of arbitrary tool-holder combinations are coupled to the spindle response to predict the speed-dependent tool point frequency response. Given this information, process dynamics predictions for spindles that exhibit dynamic changes with rotating speed are made possible without detailed knowledge of the spindle geometry, assembly tolerances, etc. Experimental results and comparisons with prediction are provided.