MEASUREMENT OF THE SPECIFIC SURFACE AREA OF POWDERS BY THIN LAYER WICKING

The specific surface areas (A) of different clay mineral powders were measured by both the BET method and by thin layer wicking. The values of A for the BET and the wicking experiments coincided within a few percent. Thus, the simple and inexpensive thin layer wicking approach may well suffice to obtain reliable specific surface area values for most powders. From the wicking data it is also possible to obtain a rough estimate of the average particle size.     

Direct finite element design optimisation of the cagelessreluctance synchronous machine

The finite element analysis method is used directly in optimisation algorithms to optimise in multidimensions the design of the cageless reluctance synchronous machine. Two optimisation methods are evaluated to minimise or maximise the function value. These are the direction set method of Powell and the quasi-Newton algorithm. Both methods proved to be successful, with some advantages and disadvantages. Using these methods at a power level below 10 kW, results are given of structures of the reluctance synchronous machine which have been optimised according to specific criteria. Calculated and measured results show that the maximum torque optimum designed reluctance synchronous machine has the advantages of high power density and high efficiency     

Comparison between normal and reverse thin crystalline silicon solar cells

The newly developed ingot growing techniques, as the three-grain and the columnar multigrain ingot processes, are now offering the possibility of slicing thinner wafers (≤ 100 μm). In this paper we present the results obtained on p type large area (≥ 100 cm²) and 100 μm thick wafers by using both conventional and reverse cell manufacturing technologies.The conventional cells are provided with aluminium or boron BSF plus screen-printed silver mirror or a silver-aluminium net; the reverse cells have a FSF and the deep back junction completely covered by a screen-printed or CVD silver layer.The constructing parameters have been chosen on the base of one and two dimensions modeling and both raw material and devices have been completely characterized.This work shows that very thin wafers do not introduce serious problems for the conventional manufacturing of solar cells. The efficiencies of the normal and of the reverse cells are found to be comparable and are of the same order than those of thicker cells, however at a significant lower cost. The main obtained result has to be related to the demonstration of a cell manufacturing feasibility starting from very thin wafers.     

Contribution of listeners' approaching motion to auditory distance perception.

Of the several sources of acoustic information for distance perception, those arising from motion of the listener or sound source have received little attention. This motion-related information (recently called acoustic tau) is described, and experiments evaluating its utilization are presented. Accuracy and consistency at walking to the locations of briefly presented sounds were better when people listened while walking than while standing still. Manipulations of the sound to simulate shorter or longer target distances produced appropriate undershooting but not overshooting. The results indicate that people use motion-related acoustic information about distance to guide their locomotor actions, although they do not take full advantage of this information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mine operating accurate stability control with optical fibersensing and Bragg grating technology: the European BRITE/EURAM STABILOSproject

Recent developments of stability control in mines, essentially based on Ge-doped fiber Bragg gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, sensor network topology and multiplexing method, user interface design and sensor packaging     

Worldwide experience with the Finetech-Brindley sacral anterior root stimulator

BACKGROUND: Serum creatinine has been reported in previous studies to be a prognostic indicator for overall mortality, in particular in a hypertensive population. METHODS: The Program on the Surgical Control of the Hyperlipidemias (POSCH) was a randomized, controlled clinical trial. All patients had survived a single myocardial infarction, were normotensive, were not obese, were not having heart failure, and were free of diabetes mellitus and renal disease at entry into the study. POSCH had followed its control group patients (N = 417) for a minimum of 7.0 years. In this group, a prospective post hoc analysis of the relationship of baseline serum creatinine with subsequent overall and atherosclerotic coronary heart disease mortality was performed. RESULTS: The baseline serum creatinine values in the control group patients ranged from 0.7 to 1.9 mg/dL (60 to 170 mumol/L), and were found to be independent predictors (P < .01) of both overall mortality and atherosclerotic coronary heart disease mortality. Each 0.1 mg/dL (9 mumol/L) increment in the baseline serum creatinine increased the relative risk for subsequent overall mortality by 36% and the relative risk for subsequent atherosclerotic coronary heart disease mortality by 47%. CONCLUSIONS: These results demonstrate that a serum creatinine value, obtained in normotensive, nonobese, normoglycemic survivors of a myocardial infarction without preexistent renal disease or heart failure, provides independent prognostic information regarding subsequent overall and atherosclerotic coronary heart disease mortality.     

Young children's (Homo sapiens) understanding of knowledge formation in themselves and others.

Three- and 4-yr-old children were tested for comprehension of knowledge formation. In Exp 1, 34 Ss watched as a surprise was hidden under 1 of 4 obscured cups. The experimenter then pointed to the cup. All children searched under the correct cup, but no 3-yr-olds (in contrast to most 4-yr-olds) could explain how they knew where to look. Ss then discriminated between simultaneous pointing by 2 adults, one who had hidden a surprise and one who had left the room before the surprise was hidden. Most 4-yr-olds (but no 3-yr-olds) showed clear discrimination between the adults. In Exp 2, 16 Ss were tested with procedures designed to make the source of their own knowledge more obvious, but this had no effect on performance. It is concluded that studies using very similar procedures with chimpanzees and rhesus macaques were measuring an ability (or inability) to understand how knowledge states form. (PsycINFO Database Record (c) 2010 APA, all rights reserved)