29,930 research outputs found
Technologies
Energy technologies to meet the power requirements of future space missions are reviewed. Photovoltaic, solar dynamic, and solar thermal technologies are discussed along with techniques for energy storage and power management and distribution
Enabling Micro-level Demand-Side Grid Flexiblity in Resource Constrained Environments
The increased penetration of uncertain and variable renewable energy presents
various resource and operational electric grid challenges. Micro-level
(household and small commercial) demand-side grid flexibility could be a
cost-effective strategy to integrate high penetrations of wind and solar
energy, but literature and field deployments exploring the necessary
information and communication technologies (ICTs) are scant. This paper
presents an exploratory framework for enabling information driven grid
flexibility through the Internet of Things (IoT), and a proof-of-concept
wireless sensor gateway (FlexBox) to collect the necessary parameters for
adequately monitoring and actuating the micro-level demand-side. In the summer
of 2015, thirty sensor gateways were deployed in the city of Managua
(Nicaragua) to develop a baseline for a near future small-scale demand response
pilot implementation. FlexBox field data has begun shedding light on
relationships between ambient temperature and load energy consumption, load and
building envelope energy efficiency challenges, latency communication network
challenges, and opportunities to engage existing demand-side user behavioral
patterns. Information driven grid flexibility strategies present great
opportunity to develop new technologies, system architectures, and
implementation approaches that can easily scale across regions, incomes, and
levels of development
STUDY OF THE FORMATION MECHANISM OF GAS HYDRATES OF METHANE IN THE PRESENCE OF SURFACE-ACTIVE SUBSTANCES
Досліджено вплив поверхнево-активних
речовин на механізм утворення газових гідратів метану. Визначено значення критичної
концентрації міцелоутворення (ККМ) розчинів дібутілфенола, обробленого окисом етилену (ДБ), а також синтанолів (ДС-10, ДС-20).
Виявлено, що завдяки процесу солюбілізації
відбувається утворення мікрогетерогенних
наночасток, які призводять до зміни складу
газогідратів і швидкості утворення
Ключові слова: газогідрати метану, міцелоутворення, поверхневий натяг, міжфазовий
електричний потенціал, швидкість утворенняИсследовано влияние поверхностно-активных веществ на механизм образования газовых гидратов метана. Определены значения
критической концентрации мицеллообразования (ККМ) растворов дибутилфенола, обработанного окисью этилена (ДБ), а также
синтанолов (ДС-10, ДС-20). Обнаружено, что
благодаря процессу солюбилизации происходит образование микрогетерогенных наночастиц, которые приводят к изменению состава
газогидратов и скорости образования
Ключевые слова: газогидраты метана,
мицеллообразование, поверхностное натяжение, межфазный электрический потенциал,
скорость образовани
Analysis and optimal design of micro-energy harvesting systems for wireless sensor nodes
Presently, wireless sensor nodes are widely used and the lifetime of the system is becoming the biggest problem with using this technology. As more and more low power products have been used in WSN, energy harvesting technologies, based on their own characteristics, attract more and more attention in this area. But in order to design high energy efficiency, low cost and nearly perpetual lifetime micro energy harvesting system is still challenging.
This thesis proposes a new way, by applying three factors of the system, which are the energy generation, the energy consumption and the power management strategy, into a theoretical model, to optimally design a highly efficient micro energy harvesting system in a real environment. In order to achieve this goal, three aspects of contributions, which are theoretically analysis an energy harvesting system, practically enhancing the system efficiency, and real system implementation, have been made. For the theoretically analysis, the generic architecture and the system design procedure have been proposed to guide system design. Based on the proposed system architecture, the theoretical analytical models of solar and thermal energy harvesting systems have been developed to evaluate the performance of the system before it being designed and implemented. Based on the model’s findings, two approaches (MPPT based power conversion circuit and the power management subsystem) have been considered to practically increase the system efficiency. As this research has been funded by the two public projects, two energy harvesting systems (solar and thermal) powered wireless sensor nodes have been developed and implemented in the real environments based on the proposed work, although other energy sources are given passing treatment. The experimental results show that the two systems have been efficiently designed with the optimization of the system parameters by using the simulation model. The further experimental results, tested in the real environments, show that both systems can have nearly perpetual lifetime with high energy efficiency
Orbital angular momentum of photons and the entanglement of Laguerre-Gaussian modes
The identification of orbital angular momentum (OAM) as a fundamental
property of a beam of light nearly twenty-five years ago has led to an
extensive body of research around this topic. The possibility that single
photons can carry OAM has made this degree of freedom an ideal candidate for
the investigation of complex quantum phenomena and their applications. Research
in this direction has ranged from experiments on complex forms of quantum
entanglement to the interaction between light and quantum states of matter.
Furthermore, the use of OAM in quantum information has generated a lot of
excitement, as it allows for encoding large amounts of information on a single
photon. Here we explain the intuition that led to the first quantum experiment
with OAM fifteen years ago. We continue by reviewing some key experiments
investigating fundamental questions on photonic OAM and the first steps into
applying these properties in novel quantum protocols. In the end, we identify
several interesting open questions that could form the subject of future
investigations with OAM.Comment: 17 pages, 7 figures; close to accepted versio
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