Isolation and Characterization of Ether Soluble Sugar-Amino Acid Interaction Products

SUMMARY— A procedure is described for isolating compounds formed during the heating of solutions containing sugars and amino acids. It consists of solvent partition into ethyl ether, concentration of the solvent, high vacuum distillation in an isolated system and a final concentration. Model systems were employed, consisting of one sugar and one source of amino acids from the group: dextrose, lactose, glycine, lysine, valine, and casein. The flavor concentrate had a strong caramel odor.
A total of 38 non-acidic and 5 acidic gas chromatographic components were observed, but none of the systems gave rise to all of these. The differences in the gas chromatographic patterns of extracts containing both sugars and amino acids and those containing sugars alone, were more quantitative than qualitative.
While many of the components remain unidentified, those positively identified were largely sugar dehydration and degradation products. One nitrogen-containing component was identified as 2-acetylpyrrole.     

应用模块化设计扩展机床应用范围

瑞士Reishauer公司推出了新一代RZ260型蜗杆砂轮硬齿面磨齿机。该机床采用模块化设计,可以不同用户的需求。     

Optimizing the Enzymatic Maceration of Foliole Purée from Hard Pieces of Hearts of Palm (Euterpe edulis Mart.) using Response Surface Analysis

Response surface analysis was applied to investigate modifications in viscosity of foliole purée treated with commercial enzyme preparations high in cellulase and endopolygalacturonase (pectinase) with changes in enzyme concentration (0.3–1.2%), incubation time (3.3–6.7 hr) and temperature (40–50°C). Foliole purée was obtained by trituration of hard pieces of hearts of palm (Euterpe edulis) and incubated in a rotating agitator. After treatment with 0.81% cellulase for ～5 hr at 50°C, a fourfold reduction in viscosity was found relative to a control sample. The minimum viscosity for this treatment was within the experimental range investigated. Optimized experimental conditions for treatment with pectinase however were outside the experimental range. The application of the cellulase preparation to the purée resulted in a 10% increase in yield of edible palm.     

MASS TRANSFER ENHANCEMENT BY SMALL FLOW OBSTACLES IN ELECTROCHEMICAL CELLS

Mass transfer enhancement by small obstacles attached to the cathode in electrolytic flow cells of 5x5 mm cross-section and 500 mm length was investigated. Double beam laser interferometry was used to observe the local mass transfer boundary layer thicknesses preceding and following rod-shaped dielectric obstacles placed normal to the direction of electrolyte flow. Flow patterns have been visualized by use of suspensions of small inert particles and dark field photography. For the evaluation of the effectiveness of mass transport enhancement, pressure drops, and limiting currents for the reduction of ferricyanide have been measured in the range of Reynolds Number 80 to 3200. The degree of enhancement increases with decreasing obstacle spacing until an optimal spacing of approximately 15 times the obstacle size is reached. A three to five-fold increase in the average mass transfer coefficient is achieved by the use of obstacles with a small fraction of the pumping power required to obtain the same limiting current by increasing the flow rate in the unobstructed channel. Small obstacles produce efficient mixing near the electrode surface, and corresponding improvement in uniformity and magnitude of mass transport rates, without increasing the energy dissipation in the bulk fluid.     

BRIDGING THE GAPS: HYBRID TRACKING FOR ADAPTIVE MOBILE AUGMENTED REALITY

Tracking accuracy in a location-aware mobile system can change dynamically as a function of the user's location and other variables specific to the tracking technologies used. This is especially problematic for mobile augmented reality systems, which ideally require extremely precise position tracking for the user's head, but which may not always be able to achieve that level of accuracy. While it is possible to ignore variable positional accuracy in an augmented reality user interface, this can make for a confusing system; for example, when accuracy is low, virtual objects that are nominally registered with real ones may be too far off to be of use.

To address this problem, we describe an experimental mobile augmented reality system that: (1) employs multiple position-tracking technologies, including ones that apply heuristics based on environmental knowledge; (2) coordinates these concurrently monitored tracking systems; and (3) automatically adapts the user interface to varying degrees of confidence in tracking accuracy. We share our experiences with managing these multiple tracking technologies, employing various techniques to facilitate smooth and reasonable “hand-offs” between the cooperating systems. We present these results in the context of an intelligent navigational guidance system that helps users to orient themselves in an unfamiliar environment, using path planning to guide them toward destinations they choose, and sometimes towards ones the system infers as equally relevant.