Deep River Science Academy

Knowledge of the dielectric properties (complex permittivities) of biomasses is critical for understanding their behaviors in a microwave field and for designing large-scale microwave systems. The present research was focused on determining the dielectric properties of different types of biomasses (sawdust, bark, fiber reject, grass, and straw) at temperatures from 25 to 700°C and frequencies in the range of 397 to 2985MHz, using cavity perturbation technique. The dielectric properties decreased during the drying (25 to 200°C) and the pyrolysis stages (200 to 400°C), but sharply increased during the biochar formation stage (400 to 700°C). At 912MHz, straw, grass, and fiber reject exhibited the greatest half-power depths at approximately 300°C, and sawdust and bark at approximately 350°C, suggesting that from room temperature to 350°C, larger material volumes can reduce costs; above 500°C, the sample size must not exceed the microwave half-power depth to prevent hot spots or uneven heating. The interaction mechanisms of microwaves with biomass can be explained as follows, during biomass drying, the dielectric changes are driven by dipolar polarization of water molecules; during pyrolysis, by polar molecules and functional groups; and during carbonization, by scattering and interface polarization within the biochar. Furthermore, the addition of the produced biochar to the raw biomass could increase the loss tangent up to 400°C, enabling faster heating and reducing energy consumptions and residence times. The dielectric properties data provided in this study can be used to design large-scale microwave systems, including selection of column diameter, sample size, and microwave frequency.

Abstract In 2013, Atomic Energy of Canada Limited (now Canadian Nuclear Laboratories) experimentally measured the damping of a straight tube with a variety of tube supports to examine low-frequency damping. These tests were motivated by the discovery of severe tube damage caused by in-plane fluidelastic instability (FEI) in the U-bend regions of new replacement recirculating steam generators (SG). The measurements were intended to assess the applicability of existing design guidelines for estimating the support-related damping of a tube. In the tests, the damping ratios of a single steam generator tube were measured using both log-decrement and power-based methods. Noncontacting excitation and position-sensing techniques were employed to improve accuracy. Initial baseline tests explored configurations with no support and drilled-hole supports of different hole sizes, and these results were compared with previously published work. Subsequent tests were performed to measure damping of tube vibration parallel to flat-bar supports. Most of the tests were performed with the tube fully submerged in still water. The tests examined the effects of fluid (water or air), natural frequency, gap width, preload, and vibration normal to the bars. This paper describes the test apparatus, methods, and analysis techniques. A summary of the results is presented. The initial baseline results showed that the damping ratios measured without any supports and with a drilled-hole support were consistent with previously published data. However, the subsequent measurements showed that, contrary to a published design guideline, the anti-vibration bars resulted in no significant additional viscous or squeeze-film damping when the vibration was parallel to the bars. On the other hand, the results did show that anti-vibration bars could introduce significant in-plane Coulomb-type damping if there was sufficient tube-to-support preload or impacting.

Veterinary RecordVolume 181, Issue 21 p. 571-571 Letters and notices Clifford Warwick, lead author of ‘Future of keeping pet reptiles and amphibians: animal welfare and public health perspective’, responds: Clifford Warwick, Corresponding Author Clifford Warwick cliffordwarwick@gmail.com Riverside House, River Lawn Road, Tonbridge, TN9 1EPe-mail: cliffordwarwick@gmail.comSearch for more papers by this author Clifford Warwick, Corresponding Author Clifford Warwick cliffordwarwick@gmail.com Riverside House, River Lawn Road, Tonbridge, TN9 1EPe-mail: cliffordwarwick@gmail.comSearch for more papers by this author First published: 25 November 2017 https://doi.org/10.1136/vr.j5413Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume181, Issue21November 2017Pages 571-571 RelatedInformation

Abstract Data sets on wetlands required for the representation of aquatic ecosystem biodiversity and systematic wetland conservation planning are typically not available or are inadequate, particularly at country‐wide scale, which hinders conservation planning. The improvement in hierarchical classification systems and increased availability of broad‐scale data sets offers new opportunities to overcome these limitations. This study demonstrates replicable methods for classifying wetland ecosystem types and condition country‐wide using broad‐scale data sets in data‐scarce countries. A country‐wide data set, compiled primarily using remote sensing techniques, was combined with regional and landscape‐setting data sets to reflect the ecological and geomorphic biodiversity of wetlands. Geographical Information Systems (GIS) were employed to model wetland types, disturbance indices and identify priority wetlands through threatened faunal species associations using existing data. Accuracy of the national data was assessed through a congruency with two local data sets. Most of the 1 680 306 ha of inland wetlands were classified as Natural (80%), of which the majority were located on Valley Floors (68%). However, the national data were found only to represent 54% of wetlands mapped at a local scale, and comparison with local data showed inaccuracies in the types and condition classifications. Problems regarding spatial data quality and scale are discussed and suggestions for improvement are provided. The desktop classification steps can be reproduced easily for other data‐scarce countries. Data sets on freshwater ecosystems can assist in raising awareness and influence policy at a national scale. Copyright © 2015 John Wiley & Sons, Ltd.