Application of axial fan theory to horizontal‐axis wind turbine

In this work a simple method is developed to evaluate the design parameters of a horizontal‐axis wind turbine (HAWT). The method applies the available data of an axial fan to a HAWT for the same arc profile blade in both machines. The method is illustrated by a numerical example with a complete design procedure in which the pitch angle and the chord of the blade are calculated. These calculated results agree with the measured data of a commercial HAWT blade. Copyright © 2006 John Wiley & Sons, Ltd.     

Use of epoxy reactivity for compatibilization of PP/PBT and PP/LCP blends

Binary blends of a reactive ethylene-based terpolymer with polybutylene terephthalate (PBT) and with a liquid crystalline polyester (LCP) were studied to clarify the possible interactions between the blended polymers. The aim was to determine the suitability of the reactive terpolymer containing epoxy reactivity as a compatibilizer in blends of polypropylene (PP) and these two polyesters. The binary blends exhibited increased viscosity during blending, changes in the crystallization of the PBT phase, and an intimate contact between the blended polymers, which pointed to strong interactions or chemical reactions between the compatibilizer and both PBT and LCP. FTIR analysis confirmed the reaction of the epoxide and formation of new esters. Most probably the carboxyl end groups of the polyesters reacted with the epoxy group of the compatibilizer. In the second part of the work the same terpolymer was shown to act as a compatibilizer in PP/PBT and PP/LCP blends. This behavior was based on good mixing with the PP phase and on the chemical reactivity or strong interactions with the polyesters demonstrated in the investigations on binary blends. Addition of 5 wt% of the compatibilizer improved the impact strength, especially in PP/PBT blends where synergistic behavior was found at compositions of 80/20 and 20/80. In PP/LCP blends, the compatibilizer significantly improved the impact strength of unnotched samples at 20 wt % LCP content. In both blends, the compatibilizer reduced the size of the dispersed domains and caused them to attach better in the matrix. © 1995 John Wiley & Sons, Inc.     

Interactive multi-frame reconstruction for mobile devices

The small size of handheld devices, their video capabilities and multiple cameras are under-exploited assets. Properly combined, the features can be used for creating novel applications that are ideal for pocket-sized devices, but may not be useful in laptop computers, such as interactively capturing and analyzing images on the fly. In this paper we consider building mosaic images of printed documents and natural scenes from low resolution video frames. High interactivity is provided by giving a real-time feedback on the video quality, while simultaneously guiding the user’s actions. In our contribution, we analyze and compare means to reach interactivity and performance with sensor signal processing and GPU assistance. The viability of the concept is demonstrated on a mobile phone. The achieved usability benefits suggest that combining interactive imaging and energy efficient high performance computing could enable new mobile applications and user interactions.     

Influence of atomic layer deposition chemistry on high-k dielectrics for charge trapping memories

In this work we report the performance of the SiO₂/Si₃N₄/HfO₂ and SiO₂/Si₃N₄/ZrO₂ stacks with emphasis on the influence of atomic layer deposition chemistry used for forming the HfO₂ and ZrO₂ blocking layers. Two Hf precursors were employed – tetrakis(ethylmethylamino)hafnium (TEMAH) and bis(methylcyclopentadienyl)methoxymethyl hafnium (HfD-04). For ZrO₂, tetrakis(ethylmethylamino)zirconium (TEMAZ) and bis(methylcyclopentadienyl)methoxymethyl zirconium (ZrD-04) were used as metal precursors. Ozone was used as the oxygen source. The structural characteristics of the stacks were examined by transmission electron microscopy and grazing incidence X-ray diffraction. The electrical properties of the stacks were studied using platinum-gated capacitor structures. The memory performance of the stacks was evaluated by write/erase (W/E) measurements, endurance and retention testing. Endurance measurements revealed the most important difference between the stacks. The films grown from TEMAH and TEMAZ could withstand a significantly higher number of W/E pulses (>3 × 10⁵ in the 10 V/?11 V, 10 ms regime), in comparison to the stacks made from HfD-04 and ZrD-04 precursors (<5 × 10³ W/E cycles). This difference in endurance characteristics is attributed mainly to the different deposition temperatures suited for these two precursors and the nature of the layer formed at the Si₃N₄/HfO₂ and the Si₃N₄/ZrO₂ interfaces.     

Flexible Manufacturing Systems' compliance to the safety standards

Safety improvements of Flexible Manufacturing Systems (FMSs) are improving usability of the system usability and also the competitiveness of the manufacturing. The aims of this study were 1) to analyze the deficiencies in and the risks of flexible manufacturing system (FMS) implementations 2) to clarify whether the systems meet the demands of safety standards and 3) to suggest safety system improvements. The study was made by using the Safety Analysis for Production Automation and the Safety Checklist for FMSs. The data were gathered by interviewing key managers and workers employed by 22 Finnish companies with FMS implementations. The study showed that although the companies considered the FM systems as one of their safest functions in the workshops, many of the systems do not fulfill the most common requirements of the safety standards. The requirements were met by 70% of the targets studied. Installation and maintenance functions best meet these requirements, whereas the layout of the systems and their mechanical structure were the most poorly designed areas. Especially poor were the safety and ergonomics of the loading/unloading stations. This paper presents additional information about the deficiencies found in the FM-systems and companies' involvement in them. The results shed new light on safety and ergonomic aspects to be considered in designing and using FM-systems. The data can be used to help industry meet safety demands and to improve the efficiency of new FMS implementations.     

Thermodynamic properties of malonic, succinic, and glutaric acids: evaporation rates and saturation vapor pressures

This work provides thermodynamic data, in particular, liquid-state saturation vapor pressures of three common slightly water soluble secondary organic aerosol components, namely, malonic, succinic, and glutaric acids. A modified tandem differential mobility analyzer system was used to measure evaporation rates of nanometer sized aqueous malonic, succinic, and glutaric acid droplets at relative humidities and temperatures relevant in the lower troposphere. Liquid phase saturation vapor pressures and other thermodynamic properties were derived from the measurements using a binary condensation model. The obtained expressions for liquid phase saturation vapor pressures compare well with extrapolated literature data. The importance of the choice of method for calculating activity coefficients is discussed.     

Extractives in the cones of Pinus species

Amount and composition of lipophilic and hydrophilic extractives were analyzed in the cones of five coniferous species, namely Pinus halepensis, P.?brutia, P.?pinea, P. sylvestris and P.?nigra, growing natively in Turkey. Lipophilic extractives amounts, identified by GC, were found to be the highest in P.?brutia (35.1?mg?g^?1) and P.?halepensis (31.3?mg?g^?1) while the lowest values were found in P.?sylvestris (9.0?mg?g^?1). Resin acids were the major lipophilic group in all cones. The predominant resin acids were abietic acid in P.?pinea, P.?halepensis and P.?brutia, dehydroabietic acid in P.?sylvestris, and isopimaric acid in P.?nigra. Compared to lipophilic extractives, the amount of total hydrophilic extractives showed similar gravimetric values while sugars and sugar alcohols were the dominant group.     

Double-groove, two-depth grating coupler for light guides

A double-groove, two-depth dielectric grating structure for high-efficiency light coupling into a light guide is introduced. We show computationally that the optimized gratings can couple a monochromatic TE- or TM-polarized light beam with nearly 100% efficiency. For an unpolarized light beam 90% efficiency can be reached. In all cases the highest achieved coupling efficiencies require that the refractive index of the grating material be greater than 1.7. The illumination and fabrication tolerances of the couplers are also analyzed.     

Tuning the "roadblock" effect in kinesin-based transport

Major efforts are underway to harness motor proteins for technical applications. Yet how to best attach cargo to microtubules that serve as kinesin-driven "molecular shuttles" without compromising transport performance remains challenging. Furthermore, microtubule-associated proteins (MAPs) can block motor protein-powered transport in neurons, which can lead to neurodegenerative diseases. Again it is unclear how different physical roadblock parameters interfere with the stepping motion of kinesins. Here, we employ a series of MAPs, tailored (strept)avidins, and DNA as model roadblocks and determine how their geometrical, nanomechanical, and electrochemical properties can reduce kinesin-mediated transport. Our results provide insights into kinesin transport regulation and might facilitate the choice of appropriate cargo linkers for motor protein-driven transport devices.