Hydrothermal upgrading of wood biomass: Influence of the addition of K2CO3 and cellulose/lignin ratio

The hydrothermal treatment of two different wood biomass samples such as cherry (hard wood) and cypress (soft wood), whose composition is different i.e. lignin, cellulose and hemicellulose were performed at 280 °C for 15 min with aq. K₂CO₃ with different concentrations (0–1 M). The soft wood biomass contains higher lignin content than hard wood biomass. The cellulose rich cherry wood biomass produced higher proportion of acetic acid than cypress. The lignin rich cypress produced the hydrocarbons with major portion of phenolic hydrocarbons and derivatives than cherry. The total oil yields from both cherry and cypress wood biomass produced 50 wt% of liquid hydrocarbons at 280 °C for 15 min with 0.5 M K₂CO₃ solution. The volatility distribution of liquid hydrocarbons showed the characteristic features of soft and hard wood biomasses.     

Novel Video Memory Reduces 45% of Bitline Power Using Majority Logic and Data-Bit Reordering

We propose a low-power two-port SRAM for real-time video processing that exploits statistical similarity in images. To minimize the discharge power on a read bitline, a majority-logic circuit decides if input data should be inverted in a write cycle, so that ldquo1rdquos are in the majority. In addition, for further power reduction, write-in data are reordered into digit groups from the most significant bit group to the least significant bit group. The measurement result of a 68-kbit video memory in a 90-nm process demonstrates that a 45% power saving is achieved on the read bitline. The speed and area overheads are 4% and 7%, respectively.     

PVC、EPR和CSM材料辐照后热氧化降解的反应动力学分析

采用气相色谱定量测量了聚氯乙烯(PVC)、乙丙橡胶(EPR)和氯磺化聚乙烯(CSM)等线缆绝缘材料经辐照后在不同温度下热老化过程中的O2消耗量.对实验数据进行了反应动力学分析,发现线缆绝缘材料的热氧化降解反应为一级反应.同时获得了不同温度下的反应常数,并与根据Arrhenius 方程计算的理论结果进行了比较.     

Identification of phenolic compounds isolated from pigmented rices and their aldose reductase inhibitory activities

Two anthocyanins (cyanidin-3-O-β-glucoside and peonidin-3-O-β-glucoside) and other phenolic (ferulic acid) were, respectively isolated from black and pigmented brown rices (Oryza sativa L. japonica) and their complete structures were determined by spectroscopic analyses (H NMR, C NMR and MALDI MASS). The HPLC profile of anthocyanins extracted from black rice showed cyanidin-3-O-β-glucoside as the first peak (85%) and peonidin 3-O-β-d-glucoside as the second (15%), while that of pigmented brown rice showed ferulic acid as the first peak (85.7%) and tocols as the second (14.3%). Several tocols were isolated and identified from the unsaponifiable fractions of both rices having some difference on their structures and amounts. The aldose reductase inhibitory activity of isolated compounds was in the following decreasing order: cyanidin-3-glucoside > quercetin > ferulic acid > peonidin-3-glucoside > tocopherol.     

Chemical compositions,fine structure and physicochemical properties of kudzu (Pueraria lobata) starches from different regions

Three commercial kudzu starches from Vietnam, Japan and Korea were used to determine chemical compositions, isoflavone compounds, fine structure and physicochemical properties. The kudzu starch from Vietnam had polygonal granules, whereas the kudzu starches from Japan and Korea contained both polygonal and spherical granules. Total protein, lipid, ash and phosphorus contents present in these kudzu starches were less than 1% (starch basis). The kudzu starch from Vietnam and Korea contained both daidzein and daidzin, whereas the kudzu starch from Japan had only daidzein. These starches had similar actual amylose contents (22.2–22.9%). However, λ_max, blue value and apparent amylose contents of the kudzu starch from Vietnam were lower than those from Japan and Korea. Amylose molecules of the kudzu starch from Vietnam had the largest average degree of polymerization (DP_n) and number of chains (NC), followed by the kudzu starches from Japan and Korea. Amylopectin molecules of the kudzu starch from Vietnam also had the largest DP_n and NC, followed by the kudzu starches from Korea and Japan. X-ray diffraction patterns of the kudzu starches from Vietnam, Japan and Korea were A-type, C-type and B-type, respectively. The kudzu starch from Vietnam was found to have the specific characteristics such as significantly high gelatinization temperature, transition enthalpy and degree of crystallinity as compared to the kudzu starch from Korea and Japan.     

Activated carbon adsorption of trichloroethylene (TCE) vapor stripped from TCE-contaminated water

Ground water contaminated with trichloroethylene (TCE) used in electronic, electric, dry cleaning and the like industries is often treated by air-stripping. In this treatment process, TCE in its vapor form is stripped from ground water by air stream and sometimes emitted into the atmosphere without any additional treatments. Activated carbon adsorption is one of the practical and useful processes for recovering the TCE vapor from the exhaust air stream. However, adsorption of the TCE vapor from the stripping air stream onto activated carbons is not so simple as that from dry air, since in the exhaust air stream the TCE vapor coexists with water vapor with relatively high concentrations. The understanding of the adsorption characteristics of the TCE vapor to be adsorbed on activated carbon in the water vapor-coexisting system is essential for successfully designing and operating the TCE recovery process. In this work, the adsorption equilibrium relations of the TCE vapor adsorption on activated carbons were elucidated as a function of various relative humidity. Activated carbon fibers (ACFs) were used as model activated carbon. The adsorption equilibrium relations were studied by the column adsorption method. The adsorption isotherms of TCE vapor adsorbed on sample ACFs were successfully correlated by the Dubinin-Radushkevich equation for both cases with and without coexistent water vapor. No effects of coexistent water vapor were found on the limiting adsorption volume. However, the adsorption characteristic energy was significantly reduced by the coexistence of water vapor and its reduction was successfully correlated with the equilibrium amount of water vapor adsorbed under the dynamic condition.     

Tomakomai Large Scale Crude Oil Fire Experiments

This paper summarizes the results of large-scale crude oil fire experiments conducted in Tomakomai, Japan, in 1998 to obtain information that could be applied to the development of firefighting strategies for, and the design of, huge petroleum storages. Arabian light-equivalent crude oil was burned in pans 5-, 10-, and 20-m in diameter. Most of the experiments were performed under favorable conditions. Measured data include external radiation, infrared image of the flame, flame temperature, gas concentration inside the flame, and other burning characteristics. The height of the strongest radiant emittance was H/D=0.1 to 0.2, where D=pan diameter and H=height from the initial fuel surface, and a kind of fireball appeared occasionally at the intermittant flame zone. Emitted smoke particles were sampled on the ground and observed with a scanning electron micrograph, and the distribution of the diameters of primary smoke particles was examined. The average diameter of primary smoke particles is 53.0 (±10.5)nm. The dependence of burning characteristics and flame structure on pan diameter is discussed. The flame height of the 20-m diameter pan fire is 1.9 (±0.3) D. The burning rate increases as the pan diameters increase, but the radiative fraction decreases as pan diameter increases.     

Theoretical analysis of atomic-scale friction in frictional-force microscopy

We perform a theoretical analysis of frictional-force microscopy(FFM) images of a cleaved graphite surface. The Tomlinson model with a single-atom tip is powerful for reproducing experimental FFM images. A mapping relation between the tip atom position and the cantilever basal position obtained by a stable equilibrium condition, gives a clear explanation of the physical meaning of FFM image patterns. This revised version was published online in June 2006 with corrections to the Cover Date.