1,549 research outputs found
Supplemental Material, sj-pdf-1-arx-10.1177_17298814221075931 - Research on the reconstruction configuration and motion behavior of unmanned metamorphic vehicle
No full textSupplemental Material, sj-pdf-1-arx-10.1177_17298814221075931 for Research on the reconstruction configuration and motion behavior of unmanned metamorphic vehicle by Jun Liu, Pengliang Yang, Mingming Lu, Lei Sun and He Huang in International Journal of Advanced Robotic Systems</p
Relating quantitative soil structure metrics to saturated hydraulic conductivity
No full textSoil structure affects saturated hydraulic conductivity (Ks) by creating highly conductive macropores that preferentially transmit soil water. In this study, we explore the relationship between Ks and macropores in an Oxyaquic Vertic Argiudoll in northeastern Kansas. Macropores were quantified from an excavation wall using multistripe laser triangulation (MLT) scanning. Soil water contents were measured at four depths within a soil lysimeter installed within 2 meters of the MLT-scanned soil profile and adjacent to an Ameriflux tower monitoring precipitation, air temperature, and solar radiation. Selected hydraulic properties of soil horizons within the lysimeter were optimized to water content data using a Markov chain Monte Carlo technique in combination with the mobile-immobile water (MIM) model in HYDRUS-1D. Estimates of Ks varied between 4198 cm d-1 in the A horizon and 0.6 cm d-1 in a 2Btss2 horizon with strongly expressed wedge structure. Approximately 87% of the variation in Ks was explained by the geometric mean of the widths of pores quantified with the MLT technique and modified by the coefficient of extensibility (COLE). The use of COLE allows the widths of the macropores obtained at dry conditions to be approximated at saturation. Two models that predict Ks from either texture or water retention data resulted in Ks estimates that were similar to each other, but significantly lower than Ks values predicted with MIM in horizons where structural pores dominate water flow. This technique shows a great deal of promise in better understanding and predicting the relationship of soil structure to water flow.Peer reviewe
A randomly structured composite PDMS/PTFE ferroelectret soft smart material
No full textPolydimethylsiloxane (PDMS) based ferroelectrets are an attractive material for the fabrication of human-based applications given their soft and compliant mechanical properties. The typical fabrication approach is to exploit specifically engineered void geometries fabricated by moulding and bonding layers together. Charge instability can be addressed by the addition of polytetrafluoroethylene (PTFE) particles but this prevents the bonding of PDMS films. This paper illustrates a new approach to obtaining PDMS ferroelectret with random voids by promoting and trapping bubbles to create cavities within a PDMS film. A mathematical model is presented to explore the connection between the percentage of trapped bubbles in the PDMS and the equivalentpiezoelectric coefficient, d33e. The process is compatible with the addition of PTFE powder to the PDMS formulation and a ratio of PTFE to PDMS of 1:3 by weight was found to increase performance achieving an initial d33e of 384 pC/N which reached a steady state value of 186 pC/N measured after 2 months after poling. The energy harvesting potential of the random void PDMS/PTFE ferroelectret was explored by cyclically compressing with a force of 300 N applied at 1 Hz. The output of the ferroelectret was found to charge a 10μF capacitor to 0.26 V after 40 seconds. The ferroelectret's performance as a pressure sensor from 0 to 300 N was explored, and the optimum formulation achieved a sensitivity of 25.2 mV/N, a nonlinearity of 4%, and hysteresis of 4.2%, demonstrating a considerable improvement over the pure PDMS ferroelectret
Contour Points based P2P Algorithm for Shape Matching and Image Retrieval
No full textBased on the extracted contours of objects from images, one point to point (P2P) method is proposed for shape matching and image retrieval. Taking contour of one object as reference, contour of another object is transformed to reach their best match, during which the similarity is evaluated by comparison of two corresponding sets of contour points. Translation, scaling and rotation are all considered in transformation, thus the algorithm is robust to objects with different position, size and posture. The experimental results are presented and compared with those from two popular shape based techniques, Hu invariant moments and Zernike moments. Performance of our new approach has proved its efficiency in both matching accuracy and computational expense, and it can be used in related applications together with the other kinds of shape features or even color features, texture features, et
Keystone taxa enhance the stability of soil bacterial communities and multifunctionality under steelworks disturbance
No full textLitter quality modulates changes in bacterial and fungal communities during the gut transit of earthworm species of different ecological groups
No full textAbstract Earthworms are keystone animals stimulating litter decomposition and nutrient cycling. However, earthworms comprise diverse species which live in different soil layers and consume different types of food. Microorganisms in the gut of earthworms are likely to contribute significantly to their ability to digest organic matter, but this may vary among earthworm species. Here, we analyse the effect of food (litter) quality on gut microbiota and their changes during the gut passage (from foregut to hindgut) of earthworms of different ecological groups. The endogeic (soil living) species Aporrectodea caliginosa and the anecic (litter feeding) species Lumbricus terrestris were fed with high- (rape leaves) and low-quality litter (wheat straw) in a microcosm experiment for 18 weeks. Irrespective of earthworm species, alpha diversity of bacterial and fungal communities changed little during the gut passage, with the composition and diversity of microbial communities in the gut generally resembling those in soil more than in litter. In addition, the low-quality litter supported higher alpha diversity and more complex communities than high-quality litter. Further, gut microbial communities of the anecic L. terrestris changed less during gut passage than those of the endogeic A. caliginosa, especially when fed low-quality litter. Our findings indicate that earthworm gut microbial communities are predominantly shaped by the soil they ingest, but are modulated by the quality of litter they feed on and earthworm ecological group. Overall, the results suggest that earthworms primarily influence soil microbiota by mixing and spreading microorganisms from different microhabitats through bioturbation rather than by digesting microorganisms.Open-Access-Publikationsfonds 202
Weighted spiking neural P systems with structural plasticity working in sequential mode based on maximum spike number
No full textVarieties of alternatives
No full textThis dissertation concerns two focus particles (jiu, dou) and wh-expressions (shenme ‘what’, na geren ‘which person’) in Mandarin Chinese. These items are systematically ‘ambiguous’ and have played important roles in various aspects of Mandarin grammar. An idea based on alternatives and varieties of alternatives in particular – following Chierchia’s 2013 analysis of the polarity system – is pursued to account for the systematic ambiguities. Unambiguous semantics of jiu, dou and wh-expressions is maintained and ‘ambiguity’ explained through varieties of alternatives interacting with other independently motivated aspects of the structure they occur in. A better understanding of a large array of phenomena that involve these items – exhaustivity, distributivity, questions and conditionals – is achieved.Ph.D.Includes bibliographical referencesby Mingming Li
Bacteriophages assisted bacteria to facilitate soil multifunctionality under organochlorine pesticide contamination
No full textTransmission of macro shocks to loan losses in a deep crisis: the case of Finland
No full textBuilding on the work of Sorge and Virolainen (2006), we revisit the data on aggregate Finnish bank loan losses from the corporate sector, which covers the ‘Big Five’ crisis in Finland in the early 1990s. Several extensions to the empirical model are considered. These extensions are then used in the simulations of the aggregate loan loss distribution. The simulation results provide some guidance as to what might be the most important dimensions in which to improve the basic model. We found that making the average LGD depend on the business cycle seems to be the most important improvement. We also compare the empirical fit of the annual expected losses over a long period. In scenario-based analyses we find that a prolonged deep recession (as well as simultaneity of various macro shocks) has a convex effect on cumulative loan losses. This emphasizes the importance of an early policy response to a looming crisis. Finally, a comparison of the loan loss distribution on the eve of the 1990s crisis with the most recent distribution demonstrates the greatly elevated risk level prior to the 1990s crisis.credit risk; bank loan losses; banking crisis; macro shocks; default rates; stress testing
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