Synthesis and photovoltaic properties of novel PPV-derivatives tethered with spiro-bifluorene unit for polymer solar cells

New thermally robust photoactive arylenevinylene-based conjugated polymers, poly[3,6-bis(3,7-dimethyloctyloxy)-9,9-spirobifluorenyl-2,7-vinylene] [(OC₁₀)₂-spiro-PFV] and poly[{3,6-bis(3,7-dimethyloctyloxy)-9,9-spirobifluorenyl-2,7-vinylene}-co-2-{methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene}] [(OC₁₀)₂-spiro-PFV-co-MEH-PPV], were synthesized and used to fabricate polymer solar cells. Bulk heterojunction solar cells fabricated by blending the new copolymers, spiro-PFV and (OC₁₀)₂-spiro-PFV-co-MEH-PPV, as an electron donor with the fullerene derivative, [6,6]-phenyl C₆₁ butyric acid methyl ester (PCBM) as an electron acceptor. The effects of electron donor to acceptor ratio, thickness of photoactive layer, and the cathode structures on the power conversion efficiency (PCE) in polymer solar cells were studied. The copolymer feed ratio was found to have a considerable effect on the PCE. The maximum PCE of 1.30% was achieved with (OC₁₀)₂-spiro-PFV-co-MEH-PPV.     

Application of pulsed corona induced plasma chemical process to an industrial incinerator

Pulsed corona induced plasma chemical process (PPCP) has been investigated for the simultaneous removal of NO(x) (nitrogen oxides) and SO2 (sulfur dioxide) from the flue gas emission. It is one of the world's largest scales of PPCP for treating NO(x) and SO2 simultaneously. A PPCP unit equipped with an average 120 kW modulator has been installed and tested at an industrial incinerator with the gas flow rate of 42 000 m3/h. To improve the removal efficiency of SO2 and NO(x), ammonia (NH3) and propylene (C3H6) were used as chemical additives. It was observed that the pulsed corona induced plasma chemical process made significant NO(x) and SO2 conversion with reasonable electric power consumption. The ammonia injection was very effective in the enhancement of SO2 removal. NO removal efficiency was significantly improved by injecting a C3H6 additive. In the experiments, the removal efficiencies of SO2 and NO(x) were approximately 99 and 70%, respectively. The specific energy consumption during the normal operation was approximately 1.4 Wh/m3, and the nanopulse conversion efficiency of 64.3% was achieved with the pulsed corona induced plasma chemical process.     

Effects of Repeated Microcellular Foaming Process on Cell Morphology and Foaming Ratio of Microcellular Plastics

Microcellular plastics (MCPs) are manufactured through a batch process comprised of saturation and foaming stages. In the saturation process, gas molecules are dissolved into plastic in a high-pressure vessel. Following the saturation process, micro-cells are formed inside the plastic as the gas-dissolved plastic sample undergoes the foaming process. In this paper, we investigate the effects of repeating the batch process on the formation of MCPs. Because the plastic sample after the first batch process has developed microcells, these pre-existing cells are expected to affect the second round of the batch process. Of particular interest is the effect of repeated saturation at different saturation pressures. Experiments show that repeating the batch process can lead to favorable outcomes in terms of foaming ratio and cell morphology, which are otherwise unattainable particularly with a single batch process.     

Active control of low-frequency noise in bubbly water-filled pipes

This paper describes an active silencer system for low-frequency noise in water-filled pipes, with implementation in marine vessels and structures in mind. Active noise control in underwater environment has its unique challenges arising from bubbles. In this light the effect of bubbles on active noise control in water-filled pipes is explored, and a design guideline for a robust active silencer is proposed. The silencer consists of an underwater sound source, an error hydrophone, and an electronic controller programmed with an adaptive filter. The adaptive filter is updated using the filtered-x least mean square algorithm. Estimation of the incoming noise is performed using an adaptive notch filter. The performance of the active silencer is tested for pure tone noises below 500 Hz in a water-filled pipe connected to a reservoir. Notable reduction of noise is achieved with varying degrees of success at different bubble fractions.

     

Hybrid solar cells based on tetrapod nanocrystals: The effects of compositions and type II heterojunction on hybrid solar cell performance

We synthesized oleic acid capped tetrapod nanocrystals of CdSe, CdTe and type II heterostructured CdTe/CdSe to investigate the effects of nanocrystal compositions and type II heterojunction on the photovoltaic properties of hybrid solar cells. The hybrid solar cell based on the blend of CdSe tetrapod nanocrystals and P3HT with a weight ratio of 6:1 showed the maximum power conversion efficiency of 1.03% under AM 1.5 G condition, and the maximum incident photon to current conversion efficiency of the solar cell was 43% at 415 nm. Although CdTe and CdTe/CdSe tetrapod nanocrystals showed relatively poor performance, the power conversion efficiency and the short circuit current density of the hybrid solar cell based on type II heterostructured CdTe/CdSe tetrapod nanocrystals was 4.4 and 3.9 times higher than that of the solar cell based on CdTe tetrapod nanocrystals, respectively. These results can be explained by the effects of nanocrystal compositions and type II heterojunction on the photovoltaic properties of hybrid solar cells.     

Wireless sensor networks as part of a web-based building environmental monitoring system

The presented research shows how advanced wireless sensor technology can be used by engineers to monitor conditions in and around buildings. The objective is split into three different tasks. First, wireless sensor hardware is programmed to process signals from sensors and transmit the data in a suitable format. This task was accomplished through an open-source operating system and a programming language designed specifically for wireless sensor hardware. The second task involved the processing of signals sent by the wireless sensor nodes. In this application, a Java program was written that deciphered messages transmitted from a wireless receiver over a computer's serial port and then placed the data in a database. The structure of that database is discussed to help identify the key pieces of information that are needed to make use of the data. The third piece of the proposed monitoring system is an interface to review the data. A Web-based system was developed that allows a user to mine the database using parameters such as the type of data, location of sensor, and the time of data acquisition. It is anticipated that this research will demonstrate the potential of using wireless sensor networks for monitoring buildings.     

Antioxidant and anticancer effects of extracts from fermented Haliotis discus hannai with Cordyceps militaris mycelia

Food Science and Biotechnology - In this study, Haliotis discus hannai (H. discus hannai) was fermented using Cordyceps militaris (C. militaris) and was investigated for the improvement of its...     

Single-step high-speed nanogranulation of metal alloy around carbon nanotubes by flash light irradiation

We demonstrate to decorate carbon nanotubes (CNTs) with metal alloy nanoparticles by flash light from a xenon lamp highlighting dramatically simplified process and ultrafast speed of millisecond. By managing the pulse energy of the irradiation, we customize the nucleation and growth rates of homogeneous binary and ternary nanoparticles with Pt–Ru and Pt–Ru–Mo thin layers that are e-beam deposited onto CNTs. No damage of CNTs during the light-induced nanogranulation is guaranteed by the rapid and surface-localized heating mechanism. The fabricated nanoparticle/CNT nanostructures are characterized using variety of microscopic and spectroscopic techniques such as SEM, TEM and Raman spectroscopy.     

Multi-pulsed white light sintering of printed Cu nanoinks

Pulse management of white light to maximize the sintering efficiency of a rapid (msec) and substrate-protective method, intense pulsed light (IPL), was studied systematically with a printable Cu nanoink. An excessive pulse energy that induces deleterious defects on the Cu film along with damage on a plastic substrate was dissipated into multiple sub-pulses while maintaining a total energy budget over the threshold level for successful Cu sintering. Electrical properties of the metal layers were analyzed in conjunction with pulse formation factors such as average energy, pulse duration, peak power and pulse number to determine their respective effects on IPL sintering. In the quantitative results, the optimized sintering conditions of copper nanoparticles with a mean diameter of 30 nm and a fixed total irradiated pulse energy of 32 J cm(-2) were a pulse number and pulse width of > 4 and < 3 msec, respectively.     

Size characterization of incinerator fly ash using sedimentation/steric field-flow fractionation

Fly ash particles emitted from municipal solid waste-incinerators are of environmental concern. This study aims to investigate the applicability of sedimentation/steric field-flow fractionation (Sd/StFFF) and to develop a Sd/StFFF method for the separation and size characterization of incinerator fly ash. This study focuses on the fly ash particles larger than approxiamtely 1 microm, which comprise more than 90% (w/w) of the fly ash. Fly ash is a complex mixture of particles having various chemical compositions, sizes, shapes, and densities. Prior to Sd/StFFF analysis, fly ash particles are prefractionated into six density classes using a modified centrifugal procedure. It was found that fly ash particles are most abundant in the density range between 2.4 and 2.8 g/cm3. Different density fractions seem to contain particles of different chemical compositions. The Sd/StFFF conditions for the size-characterization of fly ash are sample concentration, approximately 0.3% (w/v); dispersing medium, 50% ethanol in water; and carrier liquid, water with 1.0% FL-70 (ionic strength approximately 0.012 M). Sd/StFFF data show no significant differences in size distribution among different density fractions. Generally, the sizes obtained from Sd/StFFF are larger than those obtained from a Coulter Multisizer and microscopy, probably because of the irregular shapes of the fly ash particles.