Droplet impact and spreading on lecithinated anhydrous milkfat surfaces

Droplet impact and spreading is an important phenomenon that contributes to the quality of the coatings applied to food powders in air-suspension coating operations. This work investigates the dynamics of spreading 2.8 mm droplets containing maltodextrin DE5 at 20 wt% and 40 wt% in water, at an impact velocity of 2.6 m s⁻¹. The impact surface was anhydrous milkfat which was treated with three food-grade lecithin products to alter the surface hydrophobicity. Results were analysed with respect to the maximum spread diameter achieved 2 ms after impact and the final spread diameter achieved 2–4 s later. Lecithination of the surface did not affect the maximum spread diameter but resulted in greater final spread diameters. This is because lecithination reduces the equilibrium contact angle of the droplet on the surface. However, addition of lecithin to the droplet produced the same final spread diameters regardless of the surface treatment. This has the processing advantage where only the coating formulation need be manipulated to obtain the best spreading characteristics and avoid the extra processing step to modify the chemical characteristics of the substrate surface.     

Ultra-low-noise indium-phosphide MMIC amplifiers for 85-115 GHz

This paper describes a high-performance indium-phosphide monolithic microwave integrated circuit (MMIC) amplifier, which has been developed for cooled application in ultra-low-noise imaging-array receivers. At 300 K, the four-stage amplifier exhibits more than 15-dB gain and better than 10-dB input and output return loss from 80 to 110 GHz. The room-temperature noise figure is typically 3.2 dB, measured between 90-98 GHz. When cooled to 15 K, the gain increases to more than 18 dB and the noise figure decreases to 0.5 dB. Only one design pass was required to obtain very good agreement between the predicted and measured characteristics of the circuit. The overall amplifier performance is comparable to the best ever reported for MMIC amplifiers in this frequency band     

Energy Exchange Alpen Adria: Marktmodell und Implementierung

The deregulation and opening of energy markets give consumers the possibility to select their supplier. This liberalization process can be seen as requirement for more open and frequent energy trading transactions which should lead to more transparent and decreasing electricity prices for the consumers. Hence, up-coming power exchanges enable participants to benefit from possible price margins at transparent energy trading places. This paper describes the market model and the software system for the auction algorithm of the EXAA — Energy Exchange Alpen Adria. As a first step a spot market will be implemented only. The system is fully web based and very user friendly in order to attract many market participants.     

Hiperlan/2 and IEEE 802.11a—Two novel standards for high speed wireless multimedia networking in the 5 GHz band

Two major standardization bodies, the IEEE in the US, and ETSI BRAN in Europe, have recently approved standards for broadband wireless multimedia communications in the 5 GHz band. The physical layers (PHYs) of the two standards, IEEE 802. 11a and ETSI BRAN Hiperlan/2, respectively, have largely been harmonized, while the medium access control (MAC) layers differ significantly. In this paper we give an overview of the physical layers of the two standards, and we present PHY performance simulation results for typical indoor environments.     

A bright future

“I'm very encouraged to see the current level of interest in renewables and hope that the firm policy directives that are increasingly coming from Government will translate into funding and local action,” says Dr Mary Archer, current president of the UK section of ISES. She explained to Nina Morgan how she believes that growing public awareness combined with government environmental targets will help promote the use and development of renewable energy sources in the UK.     

The hard science of Rorschach research: What do we know and where do we go?

As the final article in the Special Series on "The Utility of the Rorschach for Clinical Assessment," the authors provide an overview of this instrument's current status. They begin with a thorough review of global and focused meta-analyses, including an expanded analysis of K. C. H. Parker et al's (see record 1989-14153-001) data set, and conclude that Rorschach, MMPI, and IQ scales each produce roughly similar effect size magnitudes, although all tests have greater validity for some purposes than for others. Because this evidentiary foundation justifies addressing other issues, the authors build on contributions to the Special Series to identify 11 salient theoretical and empirical gaps in the Rorschach knowledge base and make recommendations for addressing these challenges to further the evolution of the Rorschach and document its strengths and inherent limitations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A general method to estimate wind farm power using artificial neural networks

An artificial neural network (ANN) is trained and validated using a large dataset of observations of wind speed, direction, and power generated at an offshore wind farm (Lillgrund in Sweden). In its traditional form, the ANN is used to generate a new two‐dimensional power curve, which predicts with high accuracy (bias ～?0.5% and absolute error ～2%) the power of the entire Lillgrund wind farm based on wind speed and direction. By contrast, manufacturers only provide one‐dimensional power curves (i.e., power as a function of wind speed) for a single turbine. The second innovative application of the ANN is the use of a geometric model (GM) to calculate two simple geometric properties to replace wind direction in the ANN. The resulting GM‐ANN has the powerful feature of being applicable to any wind farm, not just Lillgrund. A validation at an onshore wind farm (Nørrekær in Denmark) demonstrates the high accuracy (bias ～?0.7% and absolute error ～6%) and transfer‐learning ability of the GM‐ANN.