CO2 process intensification of algae oil extraction to biodiesel

Algae-to-biodiesel processes are hindered by high costs and low energy return on investment.^1,2. Herein, three foci in research improve algae-to-biodiesel processes by: (1) reducing high installation and energy costs in the CO₂ sequestration, cultivation, and harvesting stages; (2) improving oil extraction and biodiesel generation; and (3) increasing utilization of the proteins in lipid-extracted biomass (e.g., for animal feed), as well as the omega-3 fatty acids for nutraceuticals and food supplements. A process is introduced that uses carbon dioxide to aid in all three of these foci. CO₂ is used first in the form of microbubbles to lyse algae cell walls, releasing triglyceride oils. CO₂ also aids with transesterification of these triglycerides using methanol. At low temperatures (353.15–368.15 K) and intermediate pressures (5–10 MMPa), carbon dioxide causes methanol to dissolve partially in the triglyceride phase and triglyceride to dissolve partially in the methanol phase, increasing the transesterification reaction rate. Due to the nondestructive nature of these processes, other metabolites can also be harvested providing improvements in both mass and economic efficiency with an overall sharp reduction in the modeled price of biodiesel.     

Microstructural Analysis and Transport Properties of Thermally Sprayed Multiple-Layer Ceramic Coatings

Multilayer, graded ceramic/metal coatings were prepared by an air plasma spray method on Ti-6Al-4V, 4140 steel and graphite substrates. The coatings were designed to provide thermal barriers for diesel engine pistons to operate at higher temperatures with improved thermal efficiency and cleaner emissions. A systematic, progressive variation in the mixture of yttria-stabilized zirconia and bondcoat alloys (NiCoCrAlYHfSi) was designed to provide better thermal expansion match with the substrate and to improve thermal shock resistance and cycle life. Heat transfer through the layers was evaluated by a flash diffusivity technique based on a model of one-dimensional heat flow. The aging effect of the as-sprayed coatings was captured during diffusivity measurements, which included one heating and cooling cycle. The hysteresis of thermal diffusivity due to aging was not observed after 100-h annealing at 800 °C. The measurements of coatings on substrate and freestanding coatings allowed the influence of interface resistance to be evaluated. The microstructure of the multilayer coating was examined using scanning electron microscope and electron probe microanalysis.     

Effect of Active Lengthening and Shortening on Small-Angle X-ray Reflections in Skinned Skeletal Muscle Fibres

Our purpose was to use small-angle X-ray diffraction to investigate the structural changes within sarcomeres at steady-state isometric contraction following active lengthening and shortening, compared to purely isometric contractions performed at the same final lengths. We examined force, stiffness, and the 1,0 and 1,1 equatorial and M3 and M6 meridional reflections in skinned rabbit psoas bundles, at steady-state isometric contraction following active lengthening to a sarcomere length of 3.0 µm (15.4% initial bundle length at 7.7% bundle length/s), and active shortening to a sarcomere length of 2.6 µm (15.4% bundle length at 7.7% bundle length/s), and during purely isometric reference contractions at the corresponding sarcomere lengths. Compared to the reference contraction, the isometric contraction after active lengthening was associated with an increase in force (i.e., residual force enhancement) and M3 spacing, no change in stiffness and the intensity ratio I_1,1/I_1,0, and decreased lattice spacing and M3 intensity. Compared to the reference contraction, the isometric contraction after active shortening resulted in decreased force, stiffness, I_1,1/I_1,0, M3 and M6 spacings, and M3 intensity. This suggests that residual force enhancement is achieved without an increase in the proportion of attached cross-bridges, and that force depression is accompanied by a decrease in the proportion of attached cross-bridges. Furthermore, the steady-state isometric contraction following active lengthening and shortening is accompanied by an increase in cross-bridge dispersion and/or a change in the cross-bridge conformation compared to the reference contractions.     

Prediction of plasticizer solvency using hansen solubility parameters

The solvating strength of a plasticizer for poly(vinyl chloride) resin is a measure of the interactive forces between these two materials. Hansen's three-dimensional solubility parameters provide a quantitative measure of these interactive forces. By using CO-ACT^SM service, a computer program designed for solvent systems with various resins, plasticizers were found to lie near the edge of the solvency “sphere” of PVC. The relative positions of various plasticizer structures are in the expected order, while known solvents show strong association and lubricating additives fall outside the solvency sphere of PVC.     

Turbulent winds and pressure effects around a rough cylinder at high Reynolds number

Time histories of the fluctuating wind pressure differential across the shell of a full-scale cooling tower were measured in 1974 by Princeton University personnel. Data were recorded around a single level, at the throat, at a height of ～100 m. A set of simultaneous three-minute records from these data is examined statistically in the present paper. The methods employed include spectral and correlation analyses, plus parametric time-series characterization of the data.Aside from its direct engineering interest as an aid in defining dynamic wind-loading conditions, the fluctuating flow activity around the tower throat may be interpreted as a fair example of turbulent flow about a rough circular cylinder at a Reynolds number approaching 10⁸. This aspect is emphasized in the present paper. In this situation the relation of the spectrum of the incident wind to pressure spectra about the cylindrical section may be of interest in connection with theories of the deformation of turbulence by bluff bodies. Further, the spatial distribution of the “parsimonious” parameters obtained from an autoregressive time-series analysis of the data reveals strong correlations with clearly identifiable flow phenomena around the perimeter, such as key points of the pressure distribution, flow separation, etc.The study, although limited to a single wind record, sixteen peripherally spaced pressure records, and only three minutes of selected time-history data, develops a coherent picture of a turbulent flow phenomenon at high Reynolds number.     

堆叠式LED结构实现紧凑型多通道光学耦合器

现代光学耦合器的核心是输入端的LED和输出端的光电探测器.它们被绝缘的光传导介质隔开.     

Remote,condition-based maintenance for web-enabled robotic system

The current trends in industry include an integration of information and knowledge-base network with a manufacturing system, which coined a new term, e-manufacturing. From the perspective of e-manufacturing any production equipment and its control functions do not exist alone, instead becoming a part of the holistic operation system with distant monitoring, remote quality control, and fault diagnostic capabilities. The key to this new paradigm is the accessibility to a remotely located system and having the means of responding to a changing environment, which is better suited for today's rapidly changing environment. Within the framework of the web-enabled robotic system, this paper focuses on the remote maintenance schemes with an emphasis on condition-based maintenance strategies. Real-time monitoring of robot harmonic drive systems and operational status have been attained over the Web. A mathematical modeling of system availability has been derived in order to account for other failures that might occur in the subsystems of the robot. Compared to the schedule-based maintenance strategies, the proposed approach shows great potential for improving overall production efficiency, while reducing the cost of maintenance.     

A large-scale investigation of lateralization in cortical anatomy and word reading: Are there sex differences?

The authors report findings of a large-scale, multitask investigation of sex differences in both structural asymmetries and lateralization of word reading. Two hundred participants were tested in eight divided visual field lexical tasks, and each received a structural magnetic resonance imaging scan. The authors examined whether there was evidence for sex differences in overall measures of neuroanatomical and behavioral lateralization, in specific language tasks and brain regions, and in variation in asymmetry within and across tasks and brain regions. There was very little evidence for sex differences on any behavioral measure. The few indications of sex differences in the current report accounted for 2% or less of the individual variation in asymmetry and could not be replicated in independent subsamples. No sex differences were observed in the asymmetry of structures in Broca's and Wernicke's areas such as pars triangularis, pars opercularis, the planum temporale, planum parietale, or Heschl's gyrus. There were also no sex differences in the variability of neuroanatomical asymmetries within or between brain regions. However, a significant relationship between planum temporale and behavioral asymmetry was restricted to men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies of sintering of coal ash relevant to pulverized coal utility boilers: 1. Examination of the Raask shrinkage—electrical resistance method

The Raask shrinkage and electrical resistance method for determining the onset of sintering of fly ash has been tested on a soda lime glass, coal ASTM ashes, fly ashes and pulverized synthetic mineral mixtures. Results with the glass confirmed those of Raask and showed that particle size distribution and bulk density affected the resistance values: the sinter point was indicated by a change in the characteristic temperature coefficient of resistance. The shrinkage and electrical sinter points were usually the same, but a high Na content lignite gave 850°C for shrinkage but 600°C for characteristic resistance change. Sinter points were 200°C less for fly ash than for ASTM ash. The fly ashes had a slight enrichment of alkalies and a decrease in Fe content compared to the total ash. Holding a compact at a temperature above the sinter point gave increased strength and shrinkage, but no decrease in electrical resistance, indicating that the decrease in resistance as temperature increased was due to the establishment of contact points between particles, with little effect of the continued growth of a contact neck. Addition of pulverized sodium silicate or iron silicate glasses to a synthetic ash also reduced the sinter points, as did alkali additions, whereas addition of pyrite did not. It was concluded that the method was a valuable tool, but sources of variability had to be determined and controlled.