Solar cell efficiency tables (version 47)

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since July 2015 are reviewed. Copyright © 2015 John Wiley & Sons, Ltd.     

Generalized Titanate Ceramic Waste Form for Advanced Purex Reprocessing

Alternative dissolution processes for spent nuclear fuel lead to highly active waste streams rich in zirconium, iron, chromium, and nickel at levels that vary with fuel assembly design. A titanate ceramic phase assemblage has been developed with the flexibility to accommodate these variations in waste stream composition. Waste loadings range from 42 to 50 wt%. Leach rates are comparable to those from Synroc C.     

Estimating average daytime and daily temperature profiles within Europe

We present a methodology for estimating the average profiles of daytime and daily ambient temperature from a spatially-continuous database for any location within Europe. The primary database with 1-km grid resolution was developed by interpolation of monthly averages of 7 daily values of temperature: minimum and maximum and 5 measurements at 3-h intervals from 6:00 to 18:00 hours Greenwich Mean Time. With a little over 800 meteorological stations available, we obtained a cross-validation root mean square error of 1.0–1.2 °C, while the interpolation error is lower, at 0.5–0.7 °C.A polynomial fit was applied to estimate the daytime temperature profile (assuming only time from sunrise to sunset) from the interpolated 3-h measurements for each month. The curve fit coefficients make it possible to calculate a number of derived data, such as average daytime temperature, maximum daytime temperature and time of its occurrence within the region. An example demonstrates the coupling of the simulated daytime temperature profile with a model for assessing the relative efficiency of electricity generation by crystalline silicon photovoltaic modules.As an alternative to the polynomial fitting, a double-cosine method was applied to enable calculation of daily (24-h) temperature profiles for each month using interpolated minimum and maximum temperatures. Compared to the polynomial curve-fitting, this method does not offer lower errors, but it provides data which are more suitable for estimation of solar thermal heating or calculation of degree days for building heating/cooling.     

GRAFLOG: Understanding Drawings through Natural Language

This paper describes an experimental interactive graphics interface, GRAFLOG, in which drawings receive linguistic interpretations. It is possible to emulate linguistic interaction in situations where graphics is thought to be necessary. The paper presents examples of such a kind of dialogue and the architecture of the implementation. The paper explains how representations of drawings can be constructed by treating graphical symbols as "objects", and how a parallel linguistic interpretation for these symbols can be constructed. It highlights the relevance of "deictic expressions" and "spatial prepositions" in building the interface mechanisms between these two kinds of representations. Lastly, it shows how a reasoning component is constructed for making deductions from premises that are found in both the graphical and linguistic domains. Using GRAFLOG, it is possible to represent knowledge through words and pictures. GRAFLOG is implemented, using an object oriented programming style, in PROLOG and GKS.     

First Isolation of Legionella Pneumophila from the Canadian Great Lakes

Two of 52 water samples collected during September and October 1981 from the Canadian Great Lakes were found to contain the organism Legionella pneumophila. Both positive samples contained only Legionella pneumophila serogroup six.     

Fate and impact of organics in an immersed membrane bioreactor applied to brine denitrification and ion exchange regeneration

The application of membrane bioreactors (MBRs) to brine denitrification for ion exchange regeneration has been studied. The developed culture was capable of complete brine denitrification at 50 gNaCl.l⁻¹. Denitrification reduced to c.60% and c.70% when salinity was respectively increased to 75 and 100 g.l⁻¹, presumed to be due to reduced growth rate and the low imposed solids retention time (10 days). Polysaccharide secretion was not induced by stressed cells following salt shocking, implying that cell lysis did not occur. Fouling propensity, monitored by critical flux, was steady at 12-15 l.m⁻².h⁻¹ during salinity shocking and after brine recirculation, indicating that the system was stable following perturbation. Low molecular weight polysaccharide physically adsorbed onto the nitrate selective anion exchange resin during regeneration reducing exchange capacity by c.6.5% when operating up to complete exhaustion. However, based on a breakthrough threshold of 10 mgNO₃⁻-N.l⁻¹ the exchange capacity was comparative to that determined when using freshly produced brine for regeneration. It was concluded that a denitrification MBR was an appropriate technology for IEX spent brine recovery and reuse.     

Expansion behaviour of glass aggregates in different testing for alkali-silica reactivity

The potential for reaction between amorphous silica in recycled glass used as aggregate in concrete and alkalis in cement is the subject of debate in current concrete literature. Whilst the ASTM C1260 accelerated mortar bar method is conventionally used for rapid ASR assessment, there is doubt about its suitability for glass aggregates. This paper reports upon a comparison of the relative ASR reactivity of various colours of recycled glass aggregates using the ASTM C1260 and C227 test methodologies. The results show that with limited exception the ASTM C1260 method does not cause glass aggregates to react by the end of the prescribed test period. In contrast, the ASTM C227 method causes all glass aggregates to react within 2 weeks, despite the test being designed for 12 months or even longer if necessary. This paper compares and contrasts the results of the two methods over a wide range of glass aggregate and cementitious systems made with two sizes of mortar bar, draws conclusions about the reasons for the differences observed and makes remarks on the expansion behaviour of glass aggregates in cementitious systems.     

Comparison of potential solar electricity output from fixed‐inclined and two‐axis tracking photovoltaic modules in Europe

We present an approach to determine the potential energy gains of flat plate non‐concentrating photovoltaic systems for the case of two‐axis tracking and two inclination angles with fixed orientation (assuming biannual adjustment) compared to the configuration of single fixed optimum angle. The calculation is based on the Photovoltaic Geographic Information System (PVGIS), which integrates modelling tools with the pan‐European solar radiation database. The results indicate that in the case of a PV system with two seasonal inclination angles, the maximum yearly gains, compared to the single fixed optimum angle, do not exceed 60–70 kWh per kW_p in the Mediterranean region, while in the Baltic and North Sea regions this configuration gives less than 20 kWh extra. For the case of two‐axis tracking, the relative energy gain compared to single fixed optimum angle is highest in the Northern latitudes but the absolute gain is much higher in the South. Typical yearly gains in Portugal and the Mediterranean region are in the range of 400–600 kWh per kW_p. The smallest absolute increase is found in the Northwest and Central Europe including the British Isles, where it is lower than 250 kWh per kW_p. For crystalline silicon we also investigate the effects of temperature and shallow‐angle reflectivity on the comparison between fixed and tracking systems. While both effects reduce the overall energy output, the temperature degradation is stronger for tracking systems while the reflectivity reduces output more for fixed systems. The combined effect is almost equal for fixed and two‐axis tracking systems. Copyright © 2007 John Wiley & Sons, Ltd.     

Environmental sensor system for expanded capability of PEM fuel cell use in high air contaminant conditions

A novel device called the Environmental Sensor System has been designed and demonstrated to provide real time environmental air contaminant analysis and monitoring to allow fuel cell control systems to protect the integrity of the fuel cell from environmental contaminants. This is accomplished through continuous sampling of the ambient air used to provide oxygen to the fuel cell. Electrochemical sensors are used in this prototype device to monitor hydrogen sulfide, sulfur dioxide, nitric oxide, nitrogen dioxide and volatile organic compounds. The air is monitored before and after the air filter to allow for preventative maintenance and emergency protection. The integration of this ancillary device will allow fuel cell systems to safely and reliably operate in high air contaminant conditions which previously would have resulted in stack poisoning from air contaminants. Preliminary demonstration of this technology to protect the stack on a fuel cell electric bus is reported.