Ethanol production by co-fermentation of hexose and pentose from food wastes using Saccharomyces coreanus and Pichia stipitis

To improve the conversion rate of a saccharification liquid from food wastes containing pentoses and hexoses into bioethanol, after selecting Saccharomyces coreanus and Pichia stipitis, the respective fermentation and co-fermentation properties were investigated. In the fermentation using S. coreanus, the result under anaerobic condition was better than under aerobic conditions. In the anaerobic fermentation, the concentration of the reducing sugar and glucose remaining after 24 hrs was 9.09 and 1.88 g/L, respectively, with 40.59 g/L of ethanol produced; the ethanol productivity was 1.69 g/L-h. Also, even with the fermentation using P. stipitis, the reducing sugars and glucose were rapidly reduced, with a marked production of ethanol, but the ethanol produced was lower than those under anaerobic and aerobic conditions with the use of S. coreanus. Therefore, for the production of a high concentration of bioethanol from food wastes, ethanol fermentation was induced using S. coreanus until the middle of the fermentation, with P. stipitis used during the latter stage of the fermentation, where the circumstance favored its use, and thus, the carbon source not converted by S. coreanus was later converted to ethanol. As a result, both ethanol production of 48.63 g/L and productivity of 2.03 g/L-h increased over those of the anaerobic fermentation using S. coreanus.     

Flavonoids from the fruits of Nepalese sumac (Rhus parviflora) attenuate glutamate-induced neurotoxicity in HT22 cells

Nepalese sumac (Rhus parviflora) is a wild edible fruit used for the treatment of various ailments including neurological complications and stomach disorders in the traditional medicinal system of south Asia (Ayurveda). Four flavonoids were isolated from ethyl acetate (EtOAc) fraction of Nepalese sumac fruits and their chemical structures were determined on the basis of NMR, fast atom bombardment mass spectrometry (FAB/MS), and IR. The efficiency of isolated compounds in attenuating glutamateinduced cell death in an immortalized mouse hippocampal cell line (HT-22) and inhibition of cycline dependent kinase 5 (Cdk5) were investigated. Among the compounds, flavanols, fustin (1) and taxifolin (2), an aurone, aureusidin (3), and a biflavonoid, agathisflavone (4) were found to have protective effect against glutamate induced oxidative injury in HT22 cells. Aureusidin (3), a Cdk5/p25 inhibitor (IC₅₀ 3.5 μM), was the most potent neuroprotector with an EC₅₀ value of 11.90 μM.     

Solution-processable carbazole-based host materials for phosphorescent organic light-emitting devices

In this study, solution-processable carbazole-type host materials, 1,3-bis(3-(3,6-di-n-butylcarbazol-9-yl)phenyl)benzene (BCzPPh) and 4,6-bis(3-(3,6-di-n-butylcarbazol-9-yl)phenyl)pyrimidine (BCzPPm), were synthesized for use in phosphorescent organic light-emitting devices (OLEDs). Both host materials possess a high solubility in common organic solvents and high triplet energy to confine excitons to the phosphorescent emitter. The two nitrogen atoms in the central pyrimidine ring of BCzPPm have a profound effect on the photoluminescence properties and the electron-accepting capability. When doped with the green phosphorescent emitter tris(2-(4-tolyl)phenylpyridine)iridium (III), BCzPPh exhibited power efficiencies and external quantum efficiencies above 30 lm/W and 13%, respectively, in a simple bilayer OLED.     

Hot forging process design of sprocket wheel and environmental effect analysis

Journal of Mechanical Science and Technology - Manufacturing industries have become increasingly conscious of energy wastage and environmental emissions. The energy consumption and environmental...     

A 1.2-V 1.5-Gb/s 72-Mb DDR3 SRAM

A 1.2-V 72-Mb double data rate 3 (DDR3) SRAM achieves a data rate of 1.5 Gb/s using dynamic self-resetting circuits. Single-ended main data lines halve the data line precharging power dissipation and the number of data lines. Clocks phase shifted by 0/spl deg/, 90/spl deg/, and 270/spl deg/ are generated through the proposed clock adjustment circuits. The latter circuits make input data sampled with an optimized setup/hold window. On-chip input termination with a linearity error of /spl plusmn/4.1% is developed to improve signal integrity at higher data rates. A 1.2-V 1.5-Gb/s 72-Mb DDR3 SRAM is fabricated in a 0.10-/spl mu/m CMOS process with five metals. The cell size and the chip size are 0.845 /spl mu/m/sup 2/ and 151.1 mm/sup 2/, respectively.     

Analyzing reliability - a simple yet rigorous approach

Reliability of the electrical power system is a critical factor for continuous process operations. This paper presents an analytical method for determining distribution system reliability that can be easily implemented to form a basis for plant improvement studies. The paper demonstrates the implementation of the failure modes and effects analysis and fault tree analysis techniques based on the IEEE gold book. The analysis provides a basis for informed decisions when selecting systems designed to increase system availability. The analytical techniques are illustrated using two simple distribution schemes and it is shown how the techniques may be applied to systems that are more complex.     

Synthesis of silica-based carbon dot/nanocrystal hybrids toward white LEDs

We report herein the synthesis of silica-based carbon dots (CDs)/nanocrystal (NC) hybrids with white fluorescence and their application in white LEDs. First, silane-functionalized CDs with strong fluorescence (quantum yield = 20 %) were prepared by the hydrothermal method from citric acid and (3-aminopropyl) triethoxysilane (APTES). The optical properties of the CDs were thoroughly investigated, as well as the structural properties. Then silica-based CD/CdS NC hybrids emitting bright white light under UV excitation were realized by co-hydrolyzing the blue fluorescent CDs functionalized by APTES with yellow-emitting CdS NCs modified by (3-mercaptopropyl) trimethoxysilane (MPTMS). The hybrids show many merits, like excellent fluorescence, easy access, low cost, and good compatibility with silicone, suggesting that they could be promising candidates as white phosphors for energy-efficient optoelectronic devices. To realize their potential, a white light-emitting diode (LED) was finally fabricated by the as-prepared CD/CdS NC hybrids as converters, which exhibits white light with a color coordinate of (0.27, 0.32).     

Spray-coated organic solar cells with large-area of 12.25 cm

This study evaluated the possibility of utilizing a spray-coating process for large-area organic solar cells (OSCs) combined with a metal electrode geometry. The effects of the cell area in spray-coated OSCs were investigated systematically by introducing a metal sub-electrode and grid-electrode to realize large-area cells of up to 12.25 cm². The series resistance could be reduced significantly by inserting a metal grid-electrode into the indium tin oxide (ITO) anode, yielding a power conversion efficiency of 2.11% at a cell area of 12.25 cm² and 2.49% at an effective photocurrent generated area of 11.23 cm² under AM.1.5 simulated illumination. This is comparable to the 3.13% obtained in the cell produced by spray-coating at a cell area of 0.38 cm².     

Effect of fluorine content on the crystallization and flexural strength of fluoro-mica glass ceramics

Two glasses with different contents of fluorine were fabricated. A single phase, KMg_3.25Si_3.625O₁₀F₂, precipitated in both of the glass samples after heat treatment. Both the crystallization activation energy (En) and the frequency factor (ν) increased with increasing fluorine content. This means that the fluorine content has a dual effect on the crystallization of fluorosilicic mica glass; the effect on the frequency factor is predominant. The flexural strength of the as-cerammed glass ceramic containing more fluorine is larger than that containing less fluorine when heated to the same temperature.