Search results for "photo"
showing 10 items of 11789 documents
Technical Rules for Connecting PV Systems to the Distribution Grid: A Critical Comparison of the Italian and Vietnamese Frameworks
2018
In the last two decades, starting from the Kyoto protocol, decarbonization has promoted worldwide the rise of distributed generation from renewable energy sources. Currently, Vietnam is still showing a strong dependence on fossil fuels but with a great interest in investing in renewable, especially in photovoltaic (PV) systems. In this paper, the current Vietnamese technical and administrative framework for the connection of PV systems to the power grid is presented and critically compared to the Italian one, in order to define the bases for future cooperation in distributed generation and renewable sectors.
Optimization of photovoltaic solar power plant locations in northern Chile
2017
The optimization of photovoltaic solar power plants location in Atacama Desert, Chile, is presented in this study. The study considers three objectives: (1) Find sites with the highest solar energy potential, (2) determine sites with the least impact on the environment, and (3) locate the areas which produce small social impact. To solve this task, multi-criteria decision analyses (MCDAs) such as analytical hierarchy process and ordered weighted averaging were applied in a GIS environment. In addition, survey results of social impacts were analyzed and included into the decision-making process, including landscape values. The most suitable sites for solar energy projects were found near roa…
Homography based egomotion estimation with a common direction
2017
International audience; In this paper, we explore the different minimal solutions for egomotion estimation of a camera based on homography knowing the gravity vector between calibrated images. These solutions depend on the prior knowledge about the reference plane used by the homography. We then demonstrate that the number of matched points can vary from two to three and that a direct closed-form solution or a Gröbner basis based solution can be derived according to this plane. Many experimental results on synthetic and real sequences in indoor and outdoor environments show the efficiency and the robustness of our approach compared to standard methods.
Modular Contact-Free Conveyors for Handling Planar Fragile Objects
2017
Recent studies show that the handling of thin wafers in the photovoltaic industry can lead to unacceptable yields due to cell scratching and breaking. This paper presents the concept and design of a novel modular conveyor that is intended for handling planar fragile objects at a high speed without contact. Each element of the conveyor is a square block that is able to generate tilted air jets that lift and push the object in a single direction. Various handling functions can thus be achieved by the assembly of several blocks. To manage the complexity of assembling systems composed of hundreds of blocks, an automatized design methodology is proposed. This process gives the best topology of t…
Power losses in power-split CVTs: A fast black-box approximate method
2018
Abstract This paper addresses the mechanical losses of planetary transmissions, with particular attention to power-split CVTs in their hybrid electric versions. It provides unified layout-independent analytical relationships, which can be used for both analysis, design and control purposes, and a simplified approach; the latter overcomes the necessity to segment the operating range of the power-split CVT in order to keep its loss model physically consistent. An example of application to a real hybrid electric PS-CVT is performed to show the simplicity, accuracy and generality of the proposed method.
The numerical simulation of heat transfer during a hybrid laser–MIG welding using equivalent heat source approach
2014
International audience; The present study is dedicated to the numerical simulation of an industrial case of hybrid laser-MIG welding of high thickness duplex steel UR2507Cu with Y-shaped chamfer geometry. It consists in simulation of heat transfer phenomena using heat equivalent source approach and implementing in finite element software COMSOL Multiphysics. A numerical exploratory designs method is used to identify the heat sources parameters in order to obtain a minimal required difference between the numerical results and the experiment which are the shape of the welded zone and the temperature evolution in different locations. The obtained results were found in good correspondence with …
Assessing the accuracy of industrial robots through metrology for the enhancement of automated non-destructive testing
2016
This work presents the study of the accuracy of an industrial robot KR5 arc HW, used to perform quality inspections of components with complex shapes. Metrology techniques such as laser tracking and large volume photogrammetry were deployed to quantify both pose and dynamic path accuracies of the robot in accordance with ISO 9283:1998. The overall positioning pose inaccuracy of the robot is found to be almost 1 mm and path inaccuracy at 100% of the robot rated velocity is 4.5 mm. The maximum pose orientation inaccuracy is found to be 14 degrees and the maximum path orientation inaccuracy is 5 degrees. Despite of the significant maximum inaccuracies, uncertainty of a robotic scanning applica…
Design and Calibration of a Specialized Polydioptric Camera Rig
2017
International audience; It has been observed in the nature that all creatures have evolved highly exclusive sensory organs depending on their habitat and the form of resources availability for their survival. In this project, a novel omnidirectional camera rig, inspired from natural vision sensors, is proposed. It is exclusively designed to operate for highly specified tasks in the field of mobile robotics. Navigation problems on uneven terrains and detection of the moving objects while the robot is itself in motion are the core problems that omnidirectional systems tackle. The proposed omnidirectional system is a compact and a rigid vision system with dioptric cameras that provide a 360° f…
Microscopic Revelation of Charge-Trapping Sites in Polymeric Carbon Nitrides for Enhanced Photocatalytic Activity by Correlating with Chemical and El…
2019
The influences of chemical and electronic structures on the photophysical properties of polymeric carbon nitrides (PCNs) photocatalysts, which govern the microscopic mechanisms of the superior photocatalytic activity under visible-light irradiation, have been resolved in this work. Time-resolved photoluminescence and in situ electron paramagnetic resonance measurements indicate that the photoexcited electrons in the fractured PCNs swiftly transfer to the C2p-localized states where the trapped photoelectrons exhibit longer lifetime compared to those in the ordinary PCNs. Moreover, the structure deviation at the carbon (Cb) atoms around the bridging sites of heptazine ring units, where trappe…
Two-qubit entanglement dynamics for two different non-Markovian environments
2009
We study the time behavior of entanglement between two noninteracting qubits each immersed in its own environment for two different non-Markovian conditions: a high-$Q$ cavity slightly off-resonant with the qubit transition frequency and a nonperfect photonic band-gap, respectively. We find that revivals and retardation of entanglement loss may occur by adjusting the cavity-qubit detuning, in the first case, while partial entanglement trapping occurs in non-ideal photonic-band gap.