White paper – On the use of LiDAR data at AmeriFlux sites

Our aim is to inform the AmeriFlux community on existing and upcoming LiDAR technologies (atmospheric Doppler or Raman LiDAR often deployed at flux sites are not considered here), how it is currently used at flux sites, and how we believe it could, in the future, further contribute to the AmeriFlux vision. Heterogeneity in vegetation and ground properties at various spatial scales is omnipresent at flux sites, and 3D mapping of canopy, understory, and ground surface can help move the science forward

Application and Development of Advanced Engineering Geographical Information Systems for Pipeline Design

This thesis proposes the use of an Advanced Engineering Geographical Information System (AEGIS) for the improved design of onshore pipelines, from concept to operation. The system is novel in that it is function rather than discipline or software specific. The thesis statement has been developed, and an aim and set of research objectives identified (along with the success criteria for the evaluation of the system), based on a review of current pipeline design methods. Drawing on a design science research methodology (DSRM), the thesis proposes the development of the system as an artefact in order to validate the proposed constructs, models, methods and implementations. The thesis discusses the underlying issues of data interoperability, the application of open data standards, and the integration of computer aided design (CAD) and geographical information systems (GIS). These challenges are addressed in the thesis and demonstrated through the implementation of the system. To support the development of the system, research was undertaken in the fields of pipeline engineering, environmental engineering and engineering design. As part of this research, a number of peer-reviewed journal papers were published, and conference papers presented in Kampala, Houston, London and Split. These papers covered the key fields contained in the thesis including, fluid mechanics, bio-systems engineering, environmental engineering,CAD/GIS integration (CGI), and the application and development of geospatial pipeline data models. The thesis concludes that the approach is valid, offering significant improvement across all fields compared to the current method of pipeline design. By taking a functional approach to the challenges of the design of pipelines, a system has been developed that addresses the requirements of the pipeline engineer, environmental engineer and engineering designer. The system enables the user to select the software of their choice, thereby reducing the problems associated with data interoperability, retraining and system integration. The sharing of data and outputs from analysis carried out within the system, provides an integrated approach, which can subsequently be used for the integrity management of the pipeline during the operational phase of the project. The scope for further development of this approach to pipeline design is also discussed. In addition to the inclusion of further engineering and environmental analysis, there is the potential for using the system for the design of subsea pipelines

Effect of cutting tool assisted with vibrations on turning machined C45 samples

This thesis aims to analyse the effect of a cutting tool assisted (VAM) with 40-kHz vibration on C45 steel samples. It exposes the improvement of surface finish through vibration application and the different effects thus generated while machining process. The vibratory movement of the cutting tool is one-dimensional, and cutting tests are performed on a lathe machine. The study is mainly divided into two stages: the analyses of the effect of vibration assistance, feed and tool angle on the cutting force and roughness by means of a design of experiment. Then, the observation and characterisation of the chips removal mechanism with a high-speed camera to characterize the influence of the vibratory effect on its formation. The state of art section provide knowledge to understand the subject by exposing all the research and studies similar from our topic to justify the experiments that will be carried out. All procedures to achieve the research objectives are described, including the experimental design, experimental setup and the materials used to conduct them. It is concluded that one dimensional vibration assisted machining (VAM) offers distinct advantages over conventional machining (NVAM). The surface quality is improved when the cutting parameters are carefully implemented; adding vibration is the most significant effect on the surface quality providing lower Ra values than NVAM. VAM has demonstrated that applying vibration as a significative influence on the chip removal mechanism. Indeed, the chip fragmentation is facilitated by the VAM process by forming arc loose chips which ultimately improve the surface quality and tool wear resistance by limiting the friction due to enhanced evacuation of the chip. The texturization effects of VAM to obtain specific surface texture are also observed. From VAM to NVAM, two different patterns are easily detected (linear and mesh shape), the level intensity depends mainly on the feed rate

Power system real-time thermal rating estimation

This Thesis describes the development and testing of a real-time rating estimation algorithm developed at Durham University within the framework of the partially Government-funded research and development project “Active network management based on component thermal properties”, involving Durham University, ScottishPower EnergyNetworks, AREVA-T&D, PB Power and Imass. The concept of real time ratings is based on the observation that power system component current carrying capacity is strongly influenced by variable environmental parameters such as air temperature or wind speed. On the contrary, the current operating practice consists of using static component ratings based on conservative assumptions. Therefore, the adoption of real-time ratings would allow latent network capacity to be unlocked with positive outcomes in a number of aspects of distribution network operation. This research is mainly focused on facilitating renewable energy connection to the distribution level, since thermal overloads are the main cause of constraints for connections at the medium and high voltage levels. Additionally its application is expected to facilitate network operation in case of thermal problems created by load growth, delaying and optimizing network reinforcements. The work aims at providing a solution to part of the problems inherent in the development of a real-time rating system, such as reducing measurements points, data uncertainty and communication failure. An extensive validation allowed a quantification of the performance of the algorithm developed, building the necessary confidence for a practical application of the system developed

Objective homogeneity quantification of a periodic surface using the Gini coefficient

The significance of periodic surface structuring methods, such as direct laser interference patterning, is growing steadily. Thus, the ability to objectively and consistently evaluate these surfaces is increasingly important. Standard parameters such as surface roughness or the arithmetic average height are meant to quantify the deviation of a real surface from an ideally flat one. Periodically patterned surfaces, however, are an intentional deviation from that ideal. Therefore, their surface profile has to be separated into a periodic and a non-periodic part. The latter can then be analyzed using the established surface parameters and the periodic nature allows a quantification of structure homogeneity, e.g. based on Gini coefficient. This work presents a new combination of established methods to reliably and objectively evaluate periodic surface quality. For this purpose, the periodicity of a given surface is extracted by Fourier analysis, and its homogeneity with respect to a particular property is determined for the repeating element via a Gini analysis. The proposed method provides an objective and reliable instrument for evaluating the surface quality for the selected attribute regardless of the user. Additionally, this technique can potentially be used to both identify a suitable surface structuring technique and determine the optimal process parameters

Compact Modeling Technique for Outdoor Navigation

16 pages, 46 figures.In this paper, a new methodology to build compact local maps in real time for outdoor robot navigation is presented. The environment information is obtained from a 3-D scanner laser. The navigation model, which is called traversable region model, is based on a Voronoi diagram technique, but adapted to large outdoor environments. The model obtained with this methodology allows a definition of safe trajectories that depend on the robot's capabilities and the terrain properties, and it will represent, in a topogeometric way, the environment as local and global maps. The application presented is validated in real outdoor environments with the robot called GOLIAT.This work was supported by the Spanish Government through the MICYT project DPI2003-01170.Publicad