ROBUST TECHNIQUES FOR BUILDING FOOTPRINT EXTRACTION IN AERIAL LASER SCANNING 3D POINT CLOUDS

The building footprint is crucial for a volumetric 3D representation of a building that is applied in urban planning, 3D city modeling, cadastral and topographic map generation. Aerial laser scanning (ALS) has been recognized as the most suitable means of large-scale 3D point cloud data (PCD) acquisition. PCD can produce geometric detail of a scanned surface. However, it is almost impossible to get point clouds without noise and outliers. Besides, data incompleteness and occlusions are two common phenomena for PCD. Most of the existing methods for building footprint extraction employ classification, segmentation, voting techniques (e.g., Hough-Transform or RANSAC), or Principal Component Analysis (PCA) based methods. It is known that classical PCA is highly sensitive to outliers, even RANSAC which is known as a robust technique for shape detection is not free from outlier effects. This paper presents a novel algorithm that employs MCMD (maximum consistency within minimum distance), MSAC (a robust variant of RANSAC) and a robust regression to extract reliable building footprints in the presence of outliers, missing points and irregular data distributions. The algorithm is successfully demonstrated through two sets of ALS PCD

Predicting power consumption in continuous oscillatory baffled reactors

Continuous oscillatory baffled reactors (COBRs) have been proven to intensify processes, use less energy and produce fewer wastes compared with stirred tanks. Prediction of power consumption in these devices has been based on simplistic models developed for pulsed columns with single orifice baffles several decades ago and are limited to certain flow conditions. This work explores the validity of existing models to estimate power consumption in a COBR using CFD simulation to analyse power density as a function of operating conditions (covering a range of net flow and oscillatory Reynolds numbers: Renet=6-27/Reo=24-96) in a COBR with a single orifice baffle geometry. Comparison of computed power dissipation with that predicted by the empirical quasi-steady flow models shows that this model is not able to predict correctly the values when the flow is not fully turbulent, which is common when operating COBRs. It has been demonstrated that dimensionless power density is inversely proportional to the total flow Reynolds number in laminar flow and constant in turbulent flow, as is the case for flow in pipes and stirred tanks. For the geometry studied here P/V∗=330/ReT in laminar flow and P/V∗=1.92 in turbulent flow

Mixing performance in continuous oscillatory baffled reactors

In the current literature, there is limited information on the influence of operating parameters on spatial mixing quality and how a secondary feed should be introduced into continuous oscillatory baffled reactors (COBR) to achieve good mixing quality. This work explores for the first time the impact of the position of a secondary feed (passive non-reactive tracer) on spatial mixing performance in a COBR using transient laminar CFD simulations. Three theoretical feed positions are studied covering a range of net flow and oscillatory Reynolds numbers (Renet=6-27/Reo=24-96), the range being chosen to ensure that the flow field remains two-dimensional in all cases. Macromixing is evaluated by analysing the spatial uniformity of the tracer with the areal distribution method developed by Alberini et al. (2014a). Introduction of the secondary stream at the reactor wall or upstream of the edge of the first baffle greatly improves mixing quality due to the recirculation eddies, which assist radial mixing. However, introduction of the secondary feed at the centreline results in high axial dispersion with limited radial mixing. With an adequate introduction position, mixing quality typically increases with an increment in the velocity ratio. Nevertheless, if the net flow is too low, mixing performance decreases because the secondary stream is pushed upstream of the baffles, where it does not benefit from flow recirculation

The Geysers Geothermal Field Update1990/2010

In this report, we have presented data in four sections: (1) THE GEYSERS HISTORICAL UPDATE 1990-2010 - A historical update of the primary developments at The Geysers between 1990 and 2010 which uses as its start point Section IIA of the Monograph - 'Historical Setting and History of Development' that included articles by James Koenig and Susan Hodgson. (2) THE GEYSERS COMPREHENSIVE REFERENCE LIST 1990-2010 - In this section we present a rather complete list of technical articles and technical related to The Geysers that were issued during the period 1990-2010. The list was compiled from many sources including, but not limited to scientific journals and conference proceedings. While the list was prepared with care and considerable assistance from many geothermal colleagues, it is very possible that some papers could have been missed and we apologize to their authors in advance. The list was subdivided according to the following topics: (1) Field characterization; (2) Drilling; (3) Field development and management; (4) Induced seismicity; (5) Enhanced Geothermal Systems; (6) Power production and related issues; (7) Environment-related issues; and (8) Other topics. (3) GRC 2010 ANNUAL MEETING GEYSERS PAPERS - Included in this section are the papers presented at the GRC 2010 Annual Meeting that relate to The Geysers. (4) ADDITIONAL GEYSERS PAPERS 1990-2010 - Eighteen additional technical papers were included in this publication in order to give a broad background to the development at The Geysers after 1990. The articles issued during the 1990-2010 period were selected by colleagues considered knowledgeable in their areas of expertise. We forwarded the list of references given in Section 2 to them asking to send us with their selections with a preference, because of limited time, to focus on those papers that would not require lengthy copyright approval. We then chose the articles presented in this section with the purpose of providing the broadest possible view across all technical fields, as related to The Geysers steam-dominated geothermal system. The Geysers has seen many fundamental changes between 1990-2010 and yet the geothermal resource seems still to be robust to the extent that, long after its anticipated life span, we are seeing new geothermal projects being developed on the north and west peripheries of the field. It is hoped that this report provides a focused data source particularly for those just starting their geothermal careers, as well as those who have been involved in the interesting and challenging field of geothermal energy for many years. Despite many hurdles The Geysers has continued to generate electrical power for 50 years and its sustainability has exceeded many early researchers expectations. It also seems probable that, with the new projects described above, generation will continue for many years to come. The success of The Geysers is due to the technical skills and the financial acumen of many people, not only over the period covered by this report (1990-2010), but since the first kilowatt of power was generated in 1960. This Special Report celebrates those 50 years of geothermal development at The Geysers and attempts to document the activities that have brought success to the project so that a permanent record can be maintained. It is strongly hoped and believed that a publication similar to this one will be necessary in another 20 years to document further activities in the field

Time to look for evidence : Results-based approach to biodiversity conservation on farmland in Europe

Increased use of annual payments to land managers for ecological outcomes indicates a growing interest in exploring the potential of this approach. In this viewpoint, we drew on the experiences of all schemes paying for biodiversity outcomes/results on agricultural land operating in the EU and EFTA countries with the aim of reviewing the decisive elements of the schemes' design and implementation as well as the challenges and opportunities of adopting a results-based approach. We analysed the characteristics of results-based schemes using evidence from peer-reviewed literature, technical reports, scheme practitioners and experts in agri-environment-climate policy. We developed a typology of the schemes and explored critical issues influencing the feasibility and performance of results-based schemes. The evidence to date shows that there are at least 11 advantages to the results-based approach not found in management-based schemes with similar objectives, dealing with environmental efficiency, farmers' participation and development of local biodiversity-based projects. Although results-based approaches have specific challenges at every stage of design and implementation, for many of these the existing schemes provide potential solutions. There is also some apprehension about trying a results-based approach in Mediterranean, central and eastern EU Member States. We conclude that there is clear potential to expand the approach in the European Union for the Rural Development programming period for 2021-2028. Nevertheless, evidence is needed about the approach's efficiency in delivering conservation outcomes in the long term, its additionality, impact on the knowledge and attitudes of land managers and society at large, development of ways of rewarding the achievement of actual results, as well as its potential for stimulating innovative grassroots solutions.Peer reviewe

Hydrodynamics in a stirred tank in the transitional flow regime

The hydrodynamics in a stirred tank in the transitional flow regime have been studied experimentally and numerically with data obtained by Particle Image Velocimetry and Computational Fluid Dynamics, respectively, at three Reynolds numbers, Re = 340, 980 and 3000. The effects of impeller rotation speed and fluid properties on the underlying flow structures have been investigated. Data are analysed by mean flow fields, as well as with Proper Orthogonal Decomposition, which gives an insight into the flow dynamics by separating the spatial and temporal characteristics of the flow structures. Experimentally, it has been found that dimensionless velocity fields depend on fluid properties and impeller speed at Re = 340 and 980, whilst they are self-similar at Re = 3000. Coherent flow structures only exist however at Re = 340 and the flow is structurally different than that at higher Re. Characteristic frequencies identified for Re = 980 and 3000 are 0.03N and 0.13N, which are consistent with previous work in the literature. The simulations conducted at Re = 340 are in reasonable agreement with the experimental data, however, they do not predict a dependency of flow characteristics on fluid properties and impeller speed. This inconsistency is attributed to the difficulty of performing experiments that are free of physical perturbations, which may have a significant effect on flows at low transitional Reynolds numbers

dSAP18 and dHDAC1 contribute to the functional regulation of the Drosophila Fab-7 element

It was described earlier that the Drosophila GAGA factor [Trithorax-like (Trl)] interacts with dSAP18, which, in mammals, was reported to be a component of the Sin3–HDAC co-repressor complex. GAGA–dSAP18 interaction was proposed to contribute to the functional regulation of the bithorax complex (BX-C). Here, we show that mutant alleles of Trl, dsap18 and drpd3/hdac1 enhance A6-to-A5 transformation indicating a contribution to the regulation of Abd-B expression at A6. In A6, expression of Abd-B is driven by the iab-6 enhancer, which is insulated from iab-7 by the Fab-7 element. Here, we report that GAGA, dSAP18 and dRPD3/HDAC1 co-localize to ectopic Fab-7 sites in polytene chromosomes and that mutant Trl, dsap18 and drpd3/hdac1 alleles affect Fab-7-dependent silencing. Consistent with these findings, chromatin immunoprecipitation analysis shows that, in Drosophila embryos, the endogenous Fab-7 element is hypoacetylated at histones H3 and H4. These results indicate a contribution of GAGA, dSAP18 and dRPD3/HDAC1 to the regulation of Fab-7 function

Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom