Changes in volatile composition during fruit development and ripening of ‘Alphonso’ mango

BACKGROUND: Volatile blends of five developing and five ripening stages of mango (Mangifera indica L. cv. Alphonso) were investigated along with those of flowers and leaves. Raw and ripe fruits of cv. Sabja were also used for comparison. RESULTS: A total of 55 volatiles belonging to various chemical classes such as aldehydes, alcohols, mono‐ and sesquiterpene hydrocarbons, lactones and furanones were identified. In all Alphonso tissues monoterpenes quantitatively dominated, with 57–99% contribution; in particular, (Z)‐ocimene was found in the highest amount. Ripeness was characterized by the de novo appearance of lactones and furanones in the blend of monoterpenes. Sabja was distinguished by the abundance of monoterpene hydrocarbons in the raw fruit, and that of sesquiterpene hydrocarbons and their derivatives in the ripe stage. CONCLUSION: Various stages of the Alphonso fruit during transition from flower to ripe fruit are characterized by unique volatile signatures that are distinguished from each other by the qualitative and quantitative appearance of different volatile compounds. Thus volatiles can be highly informative markers while studying the development and ripening of mango. Copyright © 2009 Society of Chemical Industry     

Mobile robot interception using human navigational principles: Comparison of active versus passive tracking algorithms

We examined human navigational principles for intercepting a projected object and tested their application in the design of navigational algorithms for mobile robots. These perceptual principles utilize a viewer-based geometry that allows the robot to approach the target without need of time-consuming calculations to determine the world coordinates of either itself or the target. Human research supports the use of an Optical Acceleration Cancellation (OAC) strategy to achieve interception. Here, the fielder selects a running path that nulls out the acceleration of the retinal image of an approaching ball, and maintains an image that rises at a constant rate throughout the task. We compare two robotic control algorithms for implementing the OAC strategy in cases in which the target remains in the sagittal plane headed directly toward the robot (which only moves forward or backward). In the “passive” algorithm, the robot keeps the orientation of the camera constant, and the image of the ball rises at a constant rate. In the “active” algorithm, the robot maintains a camera fixation that is centered on the image of the ball and keeps the tangent of the camera angle rising at a constant rate. Performance was superior with the active algorithm in both computer simulations and trials with actual mobile robots. The performance advantage is principally due to the higher gain and effectively wider viewing angle when the camera remains centered on the ball image. The findings confirm the viability and robustness of human perceptual principles in the design of mobile robot algorithms for tasks like interception. Thomas Sugar works in the areas of mobile robot navigation and wearable robotics assisting gait of stroke survivors. In mobile robot navigation, he is interested in combining human perceptual principles with mobile robotics. He majored in business and mechanical engineering for his Bachelors degrees and mechanical engineering for his Doctoral degree all from the University of Pennsylvania. In industry, he worked as a project engineer for W. L. Gore and Associates. He has been a faculty member in the Department of Mechanical and Aerospace Engineering and the Department of Engineering at Arizona State University. His research is currently funded by three grants from the National Sciences Foundation and the National Institutes of Health, and focuses on perception and action, and wearable robots using tunable springs. Michael McBeath works in the area combining Psychology and Engineering. He majored in both fields for his Bachelors degree from Brown University and again for his Doctoral degree from Stanford University. Parallel to his academic career, he worked as a research scientist at NASA—Ames Research Center, and at the Interval Corporation, a technology think tank funded by Microsoft co-founder, Paul Allen. He has been a faculty member in the Department of Psychology at Kent State University and at Arizona State University, where he is Program Director for the Cognition and Behavior area, and is on the Executive Committee for the interdisciplinary Arts, Media, and Engineering program. His research is currently funded by three grants from the National Sciences Foundation, and focuses on perception and action, particularly in sports. He is best known for his research on navigational strategies used by baseball players, animals, and robots.     

Optimisation of the secondary ball mill using an on-line ball and pulp load sensor – The Sensomag

The ball load and pulp load have a significant influence on the ball mill product size and production capacity. To improve the circuit performance at industrial scale these variables must be tweaked to levels where the plant can get grind and capacity benefits. In most grinding circuits the influence of these variables are not quantified because it is difficult to obtain precise measurements of the pulp load for an industrial scale mill and the conventional method of obtaining ball load measurements that involves crash stops is not attractive. A comprehensive investigation was performed on an industrial scale mill to quantify the effects of both ball and pulp load. A wide range of ball and pulp loads were tested and the findings are reported in this paper. The Sensomag, a sensor developed by Magotteaux, was used to obtain ball and pulp load measurements during the experimental work.     

Effect of alkali on filaments of poly(ethylene terephthalate) and its copolyesters. II. Presence of quaternary ammonium salt in the alkali-bath

Influence of alkyl (C₁₂–C₁₄)-dimethyl-benzyl ammonium chloride in the solution of sodium hydroxide on the hydrolysis of poly(ethylene terephthalate) (PET), anionically modified poly(ethylene terephthalate) copolyster (CDP), and block polymer of poly(ethylene terephthalate)-poly(ethylene glycol) (EDP), has been studied under a variety of proportions, concentrations, time and temperature of reaction, M : L ratio, etc. Mechanical properties of treated polymeric materials are evaluated. Hydrolysis of two polymers in the same bath is compared with that in separate baths.     

Issues and trends in router design

Future routers must not only forward packets at high speeds, but also deal with nontrivial issues such as scheduling support for differential services, heterogeneous link technologies, and backward compatibility with a wide range of packet formats and routing protocols. The authors outline the design issues facing the next generation of backbone, enterprise, and access routers. The authors also present a survey of advances in router design, identifying important trends, concluding with a selection of open issues     

An empirical evaluation of virtual circuit holding time policies inIP-over-ATM networks

When carrying Internet protocol (IP) traffic over an asynchronous transfer mode (ATM) network, the ATM adaptation layer must determine how long to hold a virtual circuit opened to carry an IP datagram. We present a formal statement of the problem and carry out a detailed empirical examination of various holding time policies taking into account the issue of network pricing. We offer solutions for two natural pricing models, the first being a likely pricing model of future ATM networks, while the second is based on characteristics of current networks. For each pricing model, we study a variety of simple nonadaptive policies as well as easy to implement policies that adapt to the characteristics of the IP traffic. We simulate our policies on actual network traffic, and find that policies based on least recently used (LRU) perform well, although the best adaptive policies provide a significant improvement over LRU     

Properties of filaments spun from poly(ethylene terephthalate) chips containing PET–dust

It is observed that the thick portions in a poly(ethylene terephthalate) (PET) filament differ from the rest in their solution viscosity and birefringence, indicating that they are caused by the inhomogeneity of the polymer melt. To identify the cause of the latter, the PET chips are critically examined. It is found that the waferlike tails on the edge of the PET chips and PET–dust have slightly higher viscosity than the chips. The behavior of the chips and the dust during drying and melt spinning are examined to find whether the dust becomes postpolymerized during drying. Such dried PET–dust exhibits substantially different melting behavior than the chips. The filaments spun from the mixture of chips and PET–dust exhibit significantly higher nonuniformity in properties than the filaments spun from the chips only. It is concluded that the PET–dust entering the extruder with the chips can cause thick portions in the filaments.     

FastFabric: Scaling hyperledger fabric to 20 000 transactions per second

Blockchain technologies are expected to make a significant impact on a variety of industries. However, one issue holding them back is their limited transaction throughput, especially compared to established solutions such as distributed database systems. In this paper, we rearchitect a modern permissioned blockchain system, Hyperledger Fabric, to increase transaction throughput from 3000 to 20 000 transactions per second. We focus on performance bottlenecks beyond the consensus mechanism, and we propose architectural changes that reduce computation and I/O overhead during transaction ordering and validation to greatly improve throughput. Notably, our optimizations are fully plug‐and‐play and do not require any interface changes to Hyperledger Fabric.