Composites made from a soybean oil biopolyurethane and cellulose nanocrystals

Cellulose nanocrystals (CNC) obtained by acidic hydrolysis from microcrystalline cellulose were dispersed in a biopolyurethane matrix to prepare composite films. The polyurethane was prepared from a hydroxylated soybean oil (SO‐OH) and a polymeric diphenyldiisocyanate (pMDI), using a organotin compound as the catalyst. The composite films contained different concentrations of nanocelullose, without any macroscopic aggregates in all cases. Thermal, tensile and dynamic mechanical properties of the films were determined for all the samples. In particular, it was observed that the glass transition temperature of the nanocomposites slightly increased with the concentration of the cellulose nanocrystals. The nanocomposite with 1 wt% of nanocellulose showed the highest tensile strength of the series. POLYM. ENG. SCI., 58:125–132, 2018. © 2017 Society of Plastics Engineers     

Measuring the refractive state of an eye based on the intensity of the retinal reflex

When examining the fundus of the eye with an ophthalmoscope, the intensity of the retinal reflex depends on the refractive state of the eye. In this study, application of this phenomenon for measuring the refractive state of the eye is demonstrated. First, a calibration curve relating the intensity of the retinal reflex and the refractive state was obtained using a model eye. Next, the intensity of the retinal reflex was measured while subjects were viewing a checker-board pattern, the distance of which was varied within the range from 0.17 to 1 m. Further, the relation between the refractive state and the optical power of the stimulus could be determined based on the measured light intensity and the calibration curve. Generally, the measured refractive state increased with the optical power of the stimulus. However, blinking and fluctuations in accommodation had undesired effects on the results.     

High-power individually addressable monolithic four-beam array ofGaAlAs window diffusion stripe lasers

A window structure has been applied, for the first time, to the individually addressable monolithic array of GaAlAs high-power lasers. A 100-μm spaced array of four window diffusion stripe lasers with a long-cavity of 600 μm has been fabricated by controllable open-tube two-step diffusion and single-step metalorganic chemical vapor deposition. The window structure and the p-type active stripes with a sufficiently narrow width around 2 μm are formed by diffusion of zinc, which just passes through an n-type active layer. CW output power up to 120 mW without catastrophic damage and a threshold current around 30 mA have been achieved for each element in the wavelength range of 830 nm. Excellent uniformity of device characteristics across an array chip is confirmed. Thermal crosstalk of the elements operating simultaneously is investigated     

Design of novel efficient sensitizing dye for nanocrystalline solar cell; tripyridine-thiolato (4,,-tricarboxy-2,:,-terpyridine)ruthenium(II)

We have designed tripyridine-thiolato (4,4^′,4^″-tricarboxy-2,2^′:6^′,2^″-terpyridine)ruthenium(II) [complex 1], a novel efficient sensitizing dye for dye sensitized TiO₂ solar cells, based on the DFT MO calculations with PBE0 functional. Complex 1 is a modified BD (black dye: trithiocyanato (4,4^′,4^″-tricarboxy-2,2^′:6^′,2^″-terpyridine)ruthenium(II) complex) molecule where NCS ligands of BD are replaced by C₅H₄NS ligands. Molecular and electronic structures of complex 1 have been theoretically characterized. Complex 1 is expected to have the following two advantages over BD, in addition to the advantage of high electron transfer rate from the photoexcited dye to TiO₂ realized in BD: (1) higher electron transfer rate from redox systems to oxidized dyes; (2) higher absorption efficiency to solar spectrum. We propose complex 1 as a novel efficient sensitizing dye which provides the higher efficiency than does BD for dye sensitized solar cells.     

Uniform and high-power characteristics of 780-nm AlGaAs TQW laserdiodes fabricated by large-scale MOCVD

An approach to large-scale fabrication of high-power laser diodes lasing at a wavelength of around 780 nm is described. Heterostructures with AlGaAs triple quantum well (TQW) active layers are grown by using a metalorganic chemical vapor deposition (MOCVD) system which has a capacity of more than 12 2-in φ wafers. Taking the limitations of uniformity and the controllability of the MOCVD growth into account, we have designed the TQW-SCH (separate confinement heterostructure) structure which is suitable for high-power operation. The designed TQW-SCH structures are formed with sufficient controllability by the MOCVD. In the lasers sampled from ten epitaxial wafers grown at one time, the various room temperature characteristics exhibited excellent uniformity. The linear CW light output power versus current characteristics up to 100 mW even at 60°C are uniformly obtained over each epitaxial wafer. In preliminary aging tests at 60°C and 50 mW, a highly stable operation over 500 h has been realized. A maximum CW output power of 170 mW and a fundamental transverse mode up to 100 mW are realized at room temperature. Even at 95°C, a CW light output power of 100 mW is obtained     

Energy Planning in Small Municipalities Based on Monitoring Results and Demand Side Management

Recent estimates state that the European Union is on course to achieve only half of the 20% energy consumption reduction target by 2020. As the first governmental stakeholders involved in the implementation of energy saving initiatives, municipalities play a strategic role in the energy planning process. This paper focuses on establishment of an energy planning methodology for small municipalities with numbers of inhabitants in range of 1,000-10,000 which often face common problems associated with low efficient district heat supply systems and decreasing energy consumption in buildings. Particular attention is paid to DSM （demand side management） activities. DSM scheme includes legislative and financial flows with small investments from municipality side. Based on increased information and motivation it promotes reduction of energy consumption in all kinds of buildings. Practical experience has shown that application of DSM measures allows achieving 20% energy savings in municipal buildings during the first year.