Mass transfer kinetics of pulsed vacuum osmotic dehydration of guavas

The effects of vacuum pulse and solution concentration on mass transfer of osmotically dehydrated guava slices were studied. Kinetics of weight reduction (WR), water loss (WL), solid gain (SG) and water activity (a_w) were obtained using sucrose solutions at 40, 50 and 60 °Brix and vacuum pulse of 100 mbar for 0, 10 and 15 min at the process beginning. Higher solution concentrations and the vacuum pulse application caused an increase on WL of osmotically dehydrated guavas and reduced the samples water activity. The SG was reduced by the increase on osmotic solution concentration and favored by vacuum application. Two different models of kinetics diffusion were tested to obtain diffusivity and to compare the accuracy of these models. The effective diffusivity estimated by the hydrodynamic model well reproduced the effects of process variables on mass transfer kinetics and showed a better agreement to the experimental data than the diffusional model.     

A systems approach to improving fleet policy compliance within the US Federal Government

To reduce dependence on foreign sources of energy, address climate change, and improve environmental quality, the US government has established a goal of reducing petroleum fuel use in its federal agencies. To this end, the government requires its agencies to purchase alternative fuel vehicles, use alternative fuel, and adopt other strategies to reduce petroleum consumption. Compliance with these requirements, while important, creates challenges for federal fleet managers who oversee large, geographically dispersed fleets. In this study, a group of 25 experienced federal fleet managers participated in a pilot study using a structured methodology for developing strategies to comply with fleet requirements while using agency resources as efficiently as possible. Multi-criteria decision making (MCDM) methods were used to identify and quantify agency priorities in combination with a linear programming model to optimize the purchase of fleet vehicles. The method was successful in quantifying tradeoffs and decreasing the amount of time required to develop fleet management strategies. As such, it is recommended to federal agencies as a standard tool for the development of these strategies in the future.     

New perspectives on autobiographical memory: The integration of narrative processing and autobiographical reasoning.

Researchers from diverse psychological subdisciplines have increasingly turned their attention to the storied aspect of human thought. Narrative processing and autobiographical reasoning are 2 forms of this conscious thought. Narrative processing is the tendency to create thought units that use vivid imagery, sequential plots, characters, and salient goals. Autobiographical reasoning consists of interpreting and evaluating remembered experiences. Both forms of thought are discussed in D. P. McAdams's (see record 2001-06545-002) personality theory and D. B. Pillemer's (see record 2001-06545-003) cognitive research. S. Bluck and T. Habermas (see record 2001-06545-004) highlight developmental aspects of narrative processing and autobiographical reasoning, particularly in adolescent identity formation. U. M. Staudinger (see record 2001-06545-005) illustrates how autobiographical reasoning about memories and life stories serves as a springboard for wisdom at different stages of the life cycle. Implications for integrating subdisciplines of psychology are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The scope for potential energy savings in the flocculation process

Water treatment plants traditionally use coagulation/flocculation process to remove organics and turbidity particles in drinking water. As a result of the chemical optimisation of the coagulation process having such a strong influence, it is believed that the current hydraulic conditions for flocculation cited under best practice could be out of date. A 450 Mld plant treating upland water was chemically optimised, and it was observed that the total mixing energy input could be reduced by 66% without any detrimental impact upon the clarified water being observed. Under the new mixing regime, energy costs could be reduced by £37 300 pa equating to approximately a 280 t reduction in CO ₂.     

Solvation-Involved Nanoionics: New Opportunities from 2D Nanomaterial Laminar Membranes

Nanoporous laminar membranes composed of multilayered 2D nanomaterials (2D-NLMs) are increasingly being exploited as a unique material platform for understanding solvated ion transport under nanoconfinement and exploring novel nanoionics-related applications, such as ion sieving, energy storage and harvesting, and in other new ionic devices. Here, the fundamentals of solvation-involved nanoionics in terms of ionic interactions and their effect on ionic transport behaviors are discussed. This is followed by a summary of key requirements for materials that are being used for solvation-involved nanoionics research, culminating in a demonstration of unique features of 2D-NLMs. Selected examples of using 2D-NLMs to address the key scientific problems related to nanoconfined ion transport and storage are then presented to demonstrate their enormous potential and capabilities for nanoionics research and applications. To conclude, a personal perspective on the challenges and opportunities in this emerging field is presented.     

On the modularization and reuse of exception handling with aspects

This paper presents an in‐depth study of the adequacy of the AspectJ language for modularizing and reusing exception‐handling code. The study consisted of refactoring existing applications so that the code responsible for implementing error‐handling strategies was moved to newly created exception handler aspects. We have performed quantitative assessments of five systems—four object‐oriented and one aspect‐oriented—based on four key quality attributes, namely separation of concerns, coupling, cohesion, and conciseness. Our investigation also included a multi‐perspective analysis of the refactored systems, including (i) the extent to which error‐handling aspects can be reused, (ii) the beneficial and harmful aspectization scenarios for exception handling, and (iii) the scalability of AOP to support the modularization of exception handling in the presence of other aspects. Copyright © 2009 John Wiley & Sons, Ltd.     

Heuristics for the strip packing problem with unloading constraints

This article addresses the Strip Packing Problem with Unloading Constraints (SPU). In this problem, we are given a strip of fixed width and unbounded height, and n items of C different classes. As in the well-known two-dimensional Strip Packing problem, we have to pack all items minimizing the used height, but now we have the additional constraint that items of higher classes cannot block the way out of lower classes items. This problem appears as a sub-problem in the Two-Dimensional Loading Capacitated Vehicle Routing Problem (2L-CVRP), where one has to optimize the delivery of goods, demanded by a set of clients, that are transported by a fleet of vehicles of limited capacity based at a central depot. We propose two approximation algorithms and a GRASP heuristic for the SPU problem and provide an extensive computational experiment with these algorithms using well know instances for the 2L-CVRP problem as well as new instances adapted from the Strip Packing problem.     

Model for Analysis of Short Columns of Concrete Confined by Fiber-Reinforced Polymer

This paper presents a numerical model for evaluating the behavior of axially loaded rectangular and cylindrical short columns of concrete confined by fiber-reinforced polymer (FRP) composites. The proposed formulation considers, for unconfined and confined compressed concrete, a uniaxial constitutive relation that utilizes the area strain as a parameter of measure of the material secant axial stiffness. For unconfined concrete, the model adopts an explicit relationship between axial strain and lateral strain, while for confined concrete, an implicit relation is considered. For this last case, the model employs a simple iterative-incremental approach that describes the entire stress-strain response of the columns. The behavior of the FRP is considered linear elastic until the rupture. To validate the model, a number of columns were analyzed and the numerical results were compared with experimental values published by other authors. This comparison between experimental and numerical results indicates that the model provides satisfactory predictions of the stress-strain response of the columns.     

Carbon dioxide of Pu`u`O`o volcanic plume at Kilauea retrieved by AVIRIS hyperspectral data

A remote sensing approach permits for the first time the derivation of a map of the carbon dioxide concentration in a volcanic plume. The airborne imaging remote sensing overcomes the typical difficulties associated with the ground measurements and permits rapid and large views of the volcanic processes together with the measurements of volatile components exolving from craters. Hyperspectral images in the infrared range (1900-2100 nm), where carbon dioxide absorption lines are present, have been used. These images were acquired during an airborne campaign by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over the Pu`u` O`o Vent situated at the Kilauea East Rift zone, Hawaii. Using a radiative transfer model to simulate the measured up-welling spectral radiance and by applying the newly developed mapping technique, the carbon dioxide concentration map of the Pu`u` O`o Vent plume were obtained. The carbon dioxide integrated flux rate were calculated and a mean value of 396 ± 138 t d^− 1 was obtained. This result is in agreement, within the measurements errors, with those of the ground measurements taken during the airborne campaign.