Multilabel associative classification categorization of MEDLINE articles into MeSH keywords.

The specific characteristic of classification of medical documents from the MEDLINE database is that each document is assigned to more than one category, which requires a system for multilabel classification. Another major challenge was to develop a scalable method capable of dealing with hundreds of thousand of documents. We proposed a novel system for automated classification of MEDLINE documents to MeSH keywords based on the recently developed data mining algorithm called ACRI, which was modified to accommodate multilabel classification. Five different classification configurations in conjunction with different methods of measuring classification quality were proposed and tested. The extensive experimental comparison showed superiority of methods based on reoccurrence of words in an article over nonrecurrent-based associative classification. The achieved relatively high value of macro F1 (46%) demonstrates the high quality of the proposed system for this challenging dataset. Accuracy of the proposed classifier, defined as the ratio of the sum of TP and TN examples to the total number of examples, reached 90%. Three scenarios were proposed based on the performed tests and different possible objectives. If a goal is to classify the largest number of documents, a configuration that maximizes micro F1 should be chosen. On the other hand, if a system is to work well for categories with a small number of documents, a configuration that maximizes macro F1 is more suitable. A tradeoff can be obtained by using a configuration that optimizes the average between macro and micro F1.     

Stable range enhancement in a symmetric confocal two-rod resonator with 90/spl deg/ optical rotator

We propose a method to eliminate the narrow unstable region of a symmetric two-rod resonator with a 90/spl deg/ optical rotator which is used to compensate for thermal birefringence of the laser rod. The narrow unstable region is caused by the difference between the thermal focal lengths of the radial and tangential directions of a laser rod. Using the g-diagram analysis, we find that the narrow unstable region can be removed in the resonator configuration of a symmetric confocal type. We investigate the effect of the distance between two rods of the proposed resonator on the stability and the beam quality.     

Ultrathin silicon solar microcells for semitransparent, mechanically flexible and microconcentrator module designs

The high natural abundance of silicon, together with its excellent reliability and good efficiency in solar cells, suggest its continued use in production of solar energy, on massive scales, for the foreseeable future. Although organics, nanocrystals, nanowires and other new materials hold significant promise, many opportunities continue to exist for research into unconventional means of exploiting silicon in advanced photovoltaic systems. Here, we describe modules that use large-scale arrays of silicon solar microcells created from bulk wafers and integrated in diverse spatial layouts on foreign substrates by transfer printing. The resulting devices can offer useful features, including high degrees of mechanical flexibility, user-definable transparency and ultrathin-form-factor microconcentrator designs. Detailed studies of the processes for creating and manipulating such microcells, together with theoretical and experimental investigations of the electrical, mechanical and optical characteristics of several types of module that incorporate them, illuminate the key aspects.     

A novel diesel particulate converter

A novel design of an electrochemical reactor for filtering and continuous combustion of soot particles was developed. Such a reactor consists of a porous, oxygen-ion conducting material covered by catalytically active, electron-conductive electrodes, electrical connections and an external power supply. The manufacturing process was developed for high-porosity, ion- and electron-conducting ceramic monoliths from nanosize powders by extrusion followed by coating techniques. The performed catalytic tests proved that the efficiency of the reactor for soot removal is above 90% at low flow conditions (GHSV=13 000⁻¹) and 75% for high flow (GHSV=39 000⁻¹) in the temperature range 250–500 °C.     

Dielectric Characteristics of UV‐Curable CaCu3Ti4O12 Composite Thick Film Capacitors on Cu Foils

Dielectric composite thick films containing a high dielectric constant CaCu₃Ti₄O₁₂ (CCTO) filler in a UV‐cured polymer matrix were investigated as flexible planar capacitors on Cu foils. Dielectric performance depended on the volume fraction and size of CCTO particles dispersed in the cured polymer matrix. As a result, the thick films containing 33.3 vol.% CCTO with an average particle size of 0.47 μm exhibited a dielectric constant of ~80 and a dielectric loss of ~0.06 at 10 kHz. The effective medium theory model incorporating a morphology fitting parameter has been proven to be most close to the experimental values.     

Preparation and properties of a MnCo2O4 for ceramic interconnect of solid oxide fuel cell via glycine nitrate process

MnCo₂O₄ powder was prepared by a wet chemistry method using metal nitrates and glycine in an aqueous solution. The phase stability, sintering behavior, thermal expansion and electrical conductivity were examined to characterize powder suitability as an interconnect material in solid oxide fuel cells (SOFCs). X-ray diffraction indicated that the MnCo₂O₄ spinel synthesized by the glycine nitrate process was stable until 1100 °C and it was possible to obtain a fully densified single phase spinel. On the other hand, the MnCo₂O₄ synthesized by a solid state reaction decomposed into a cubic spinel and CoO after being sintered at 1100 °C. This might be associated with the reduction of Co³⁺ in the octahedral site of the cubic spinel phase. MnCo₂O₄ showed a thermal expansion coefficient comparable to that of other SOFCs components, as well as good electrical conductivity. Therefore, MnCo₂O₄ is a potential candidate for the ceramic interconnects in SOFCs, provided the phase instability under reducing environments can be improved.     

The Fort Totten mercury pollution risk assessment: a case history

Operational activities have resulted in mercury in the sediments surrounding Little Bay in Queens, NY. This is adjacent to Fort Totten, a formerly used defense site. Some of the mercury levels in these sediments exceeded New York State screening values. A human health risk assessment was accomplished, based on conservative assumptions. The risk assessment examined the potential for adverse health effects from direct contact with and ingestion of contaminated sediments/surface water and ingestion of biota. Potential exposures to recreational receptors including adults and children were examined. The highest numerical risk results from finfish ingestion and then second for exposure from dermal contact to the sediments. The only exposure pathway showing a hazard quotient greater than unity is finfish ingestion for the child. In summary, overall risk to this mercury exposure is minimal in spite of the state screening value being exceeded.     

Topology optimization of a PCB substrate considering mechanical constraints and heat conductivity

A material mixing method was suggested to obtain an optimal topology for a multiple material structure with multiple thermal criteria, based on Evolutionary Structural Optimization (ESO). To examine the validity of the method, it was applied to a printed circuit board (PCB) substrate. The overall efficiency of material usage in a PCB substrate was measured in terms of the combination of thermal stress and heat flux density by using a combination strategy with weighting factors. A Pareto optimal topology solution having multiple thermal criteria was obtained. The effects of weighting factors for multiple thermal criteria as well as mechanical boundary conditions on optimal topologies were investigated. It was found that as the weighting factor for heat flux density becomes larger, the sizes of holes at the center portion become larger in order to dissipate thermal energy much more efficiently. It was also found that as the magnitudes of the heat conduction are getting larger, a similar tendency of the optimal topologies is obtained to the above. The thermal stress on the clamped four sides is larger than that on the two sides clamped. It is verified that the suggested material mixing method works very well for topology optimization of a PCB substrate for various mechanical boundary conditions with multiple thermal criteria.