Super-Aerophilic Biomimetic Cactus for Underwater Dispersed Microbubble Capture,Self-Transport,Coalescence, and Energy Harvesting

Human ocean activities are inseparable from the supply of energy. The energy contained in the gas-phase components dispersed in seawater is a potential universal energy source for eupelagic or deep-sea equipment. However, the low energy density of bubbles dispersed in water introduces severe challenges to the potential energy harvesting of gas-phase components. Here, a super-aerophilic biomimetic cactus is developed for underwater dispersive microbubble capture and energy harvesting. The bubbles captured by the super-aerophilic biomimetic cactus spines, driven by the surface tension and liquid pressure, undergo automatic transport, coalescence, accumulation, and concentrated release. The formerly unavailable low-density dispersive surface free energy of the bubbles is converted into high-density concentrated gas buoyancy potential energy, thereby providing an energy source for underwater in situ electricity generation. Experiments show a continuous process of microbubble capture by the biomimetic cactus and demonstrate a 22.76-times increase in output power and a 3.56-times enhancement in electrical energy production compared with a conventional bubble energy harvesting device. The output energy density is 3.64 times that of the existing bubble energy generator. This work provides a novel approach for dispersive gas-phase potential energy harvesting in seawater, opening up promising prospects for wide-area in situ energy supply in underwater environments.     

能源计量和建模技术的研究与应用

应用动态多参数在线能源计量技术对企业范围内各用能部门的实时能耗数据进行了准确、稳定、实时的采集和存储,形成了巨量的能源数据库。依据物质平衡和能量守恒原理,运用能耗基准因数法和e-p分析方法,建立了企业生产和能量转换过程的数学模型;评估和计算了设备和工序能耗、产品能值和单位能耗;建立了单位综合能耗模型。该模型成功地应用到北京某啤酒集团的能源计量系统中,通过设备和工序能耗的分析对比,指导工艺优化和节能空间的评估,对工艺和设备能耗进行合理预测。     

Design of balanced energy savings performance contracts

Energy savings performance contracts between the energy users and the energy service companies (ESCO) are used to finance energy efficiency investments by using the future energy savings that will result from these investments. We present an analytical model to characterise the energy savings performance contracts and discuss how the risks of estimating the energy savings affect the energy user and the service provider. This characterisation allows determination of the contract parameters for a balanced contract with the information about the energy savings that are expected from the planned energy-efficiency investments. Since it is difficult to get the statistical information about the energy savings before investing in an energy-efficiency project, we develop a distribution-free contract that sets the guaranteed energy savings level based on the mean and the standard deviation of the energy savings and the profit-sharing ratio between the ESCO and the energy user. We show that a simple distribution-free balanced contract performs satisfactorily when the distribution of the energy savings is not known and its mean and the standard deviation are estimated with error. Our analytical results show that the energy savings contracts with the right parameters can mitigate the risks related to realisation of the anticipated energy savings.     

基于能量有限元法的功能梯度梁振动分析

功能梯度材料(Functionally Graded Material,FGM)由于其优良的结构性能和重要的应用价值,近些年来得到了广泛的研究和关注。采用能量有限元法对功能梯度梁和耦合梁的弯曲振动特性进行研究,推导了功能梯度材料梁的能量密度控制方程、能量有限元矩阵方程以及耦合梁的能量有限元方程,从而得到梁中的能量密度和能量流。以一简支功能梯度梁为例,分别采用该方法和传统有限元法计算了梁弯曲振动时的能量密度,通过对比验证了能量有限元法求解的准确性。在此基础上进一步对耦合功能梯度梁结构的能量密度和能量流进行了求解,得到其能量分布特征。该研究为基于能量有限元法分析复杂功能梯度材料结构的振动特性提供了理论基础。     

An energy‐based critical fatigue life prediction method for AL6061‐T6

An energy‐based critical fatigue life prediction method is developed and analysed. The original energy‐based fatigue life prediction theory states that the number of cycles to failure is estimated by dividing the total energy accumulated during a monotonic fracture by the strain energy per cycle. Because the accuracy of this concept is heavily dependent on the cyclic behaviour of the material, a precise understanding of the strain energy behaviour throughout each failure process is necessary. Examination of the stress and strain during fatigue tests shows that the cyclic strain energy behaviour is not perfectly stable as initially presumed. It was discovered that fatigue hysteresis energy always accumulates to the same amount of energy by the end of the stable energy region, which has led to a new ‘critical energy’ material property. Characterization of strain energy throughout the fatigue process has thus improved the understanding of an energy‐based fatigue life prediction method.     

High‐Capacity Cathode Material with High Voltage for Li‐Ion Batteries

Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high‐capacity electrode materials. According to the concept of energy quality, a high‐voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high‐capacity Li‐rich cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after‐treatment, and the specific energy is improved from 912 to 1033 Wh kg^?1. The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality.     

Finite element simulation of phase field model for nanoscale martensitic transformation

A finite element framework of a phase field model for nanoscale martensitic transformation is proposed on the basis of time-dependent Ginzburg–Landau kinetic equations. The bulk total free energy consists of the chemical driving energy, the interfacial energy, the elastic energy, the inertial energy (for a dynamic case), the energy due to applied field and the effects of surface energy which need to be considered at the nanoscale. Single-variant and multi-variant martensitic phase transformations in a nano-sized NiAl plate are considered. The numerical results show the effects of each energy item on the phase transformation and the self-accommodating twinned morphologies as the result of strain energy minimization.     

Comparative analysis of energy resources

This paper examines the problems encountered by a growing demand for energy consumption and a dwindling reserve of conventional energy sources Development of alternative clean energy sources should be vigorously pursued in order to improve or maintain the quality of life. The search for new energy sources has indicated the need for developing approaches to evaluate feasibility and competitiveness of the alternative sources. Frequently mentioned as alternative energy sources are wind power, water power, tidal power, coal, fission energy with or without breeders, geothermal energy, ocean thermal energy conversion, low temperature solar energy, solar power through photosynthesis and solar electric: generation. Factors considered in comparing these energy sources are given. An illustration based on United States energy consumption rates and available energy resources provide revealing information about future directions in energy production.

Requirements for economic comparative models are discussed and an example is given.     

广州某高校建筑能耗现状及节能策略分析

我国高校建筑能耗在社会总能耗中占到较大比例,存在较大节能潜力。本文通过对采用区域供冷的广州某高校近三年建筑能耗进行统计,分析获得了该校建筑能耗现状及特点,并提出了相应的节能改造措施。     

碳中和背景下氢能利用关键技术及发展现状

氢能作为一种二次能源,因其绿色、灵活、来源广泛等特点,将在可再生能源占主导的未来能源体系中发挥重要作用。决定氢能产业大规模发展的核心是实现低廉、高效的原料来源和储运。为此,从可再生能源电解水制氢和储氢运输2个方面,对实现氢能清洁和高效利用的关键技术进行了综述。总结了欧洲和日本作为氢能利用的领先国家在氢能发展方面的一些思路与进展,也对氢能的成本因素进行了讨论。分析了我国氢能发展的趋势,对于未来我国氢能产业发展的前景,提出以下建议:建立健全法规与政策体系;重视氢源供应及储运的发展;积极探索发展各类氢能利用方式。     

能源总线系统多热源混水和热回收过程变分析

在能源互联网时代,区域供冷供热系统将由原本单一形式的热源向多种形式热源并存转变,尤其是可再生能源和未利用能源。不同形式不同品位的热源集成必将引起系统能量变化。能源总线系统是集成化规模化应用区域内可再生能源及未利用能源的多源多用户能源系统。本文针对能源总线系统相对常规分散系统而言特有的多源多用户特征进行系统混水和热回收过程的变分析,将能源总线系统抽象为一系列工作在高温热源和低温热源之间的劳伦兹循环的集成,通过建立能源总线系统与常规分散系统的理想热力学模型,找到能源总线系统混水和热回收过程变的规律及影响因素。结果表明:系统的变化与各子系统低温热源进出口温度、高温热源进口温度以及高低温热源质量流量比相关,不同的设计参数会导致混水过程能量发生增加或者减小,亦或不变。通过分析得到热回收过程影响源侧总线热量变化的相关参数并找到热量变化规律,并得到最佳总线供水温度TEBS1的确定方法。     

物理学与中国能源可持续发展——献给2005世界物理年

物理学与工程技术有着密切的相互联系，能源工程技术与物理学的关系具有典型的代表性，物理学的应用可以对我国能源事业的发展做出重要的贡献。文章着重阐述了原子核物理学和核能工程（包括裂变核能和聚变核能），光电效应与光伏发电，风能、生物质能与物理学，物理化学与煤的多联产、洁净化技术，地球物理学与能源资源勘探等能源问题；讨论了物理学在节能中的三个应用：节能照明、建筑节能和交通节能；分析了中国能源的可持续发展前景     

A model of energy management analysis,case study of a sugar factory in Turkey

This study presents a case study of energy management in a sugar factory in Turkey. The main idea of the study is to analyse energy consumption, the quantity of material production, and figure out a suitable energy efficiency for the case study of a sugar factory subsequently. Firstly, a material production and energy consumption audit were performed for the sugar factory. Secondly, energy efficiency was calculated from the energy data. The SPSS (Statistical Package for the Social Sciences) statistical software was used to ensure the accuracy of the data. The factory’s energy consumption was calculated as 43,590.25 toe (tons of oil equivalent) over the last year. These results were used for CUSUM (Cumulative Sum Deviation Method) graphics. This research poses the consumption of energy, cost of energy and the relationship between energy usage and material production of sugar. The unit of energy cost was 688.22 [$/toe] for the last year. This result showed that the factory decreased the unit of energy by optimisation. The results indicated that the investigated sugar factory should pay attention to the energy management issue in order to comply with the Energy Efficiency of Turkish Law and Directives.     

Z型梁结构压电式能量采集性能分析

振动能量采集能够将外部环境中的振动能转化为电能,具有绿色可持续、节能环保、设计灵活等优势,在工业、生物、医学、军事等领域具有广阔的应用前景.为使振动型能量采集器适应更为复杂多变的工作环境,提高其采集功率和工作频带,提出一种多梁结构-Z型梁结构压电式能量采集器.理论分析了该采集器的固有振动特性,并通过有限元分析了结构尺寸...     

Hypervelocity penetration modeling: momentum vs. energy and energy transfer mechanisms

Analytic penetration modeling usually relies on either a momentum balance or an energy-rate balance to predict depth of penetration by a penetrator based on initial geometry and impact velocity. In recent years, fairly sophisticated models of penetration have arisen that develop the three-dimensional flow field within a target. Based on the flow field and constitutive assumptions, it is then possible to derive a momentum or an energy-rate balance. This paper examines the use of assumed flow fields within a target created by impact and then examines the resulting predicted behavior based on either momentum conservation or energy conservation. It is shown that for the energy-rate balance to work, the details of the energy transfer mechanisms must be included in the model. In particular, how the projectile energy is initially transferred into target kinetic energy and elastic compression energy must be included. As impact velocity increases, more and more energy during the penetration event is temporarily deposited within the target as elastic compression and target kinetic energy. This energy will be dissipated by the target at a later time, but at the time of penetration it is this transfer of energy that defines the forces acting on the projectile. Thus, for an energy rate balance approach to successfully model penetration, it must include the transfer of energy into kinetic energy within the target and the storage of energy by elastic compression. Understanding the role of energy dissipation in the target clarifies the various terms in analytic models and identifies their origin in terms of the fundamental physics. Understanding the modes of energy transfer also assists in understanding the hypervelocity result that penetration depth only slowly increases with increasing velocity even though the kinetic energy increases as the square of the velocity.     

基于宽频-多模态的复合俘能器的解析模型与实验研究

为提高单频压电振动俘能器的能量转换效率和工作频带,结合压电和电磁能量转换机制,提出了一种新的混合俘能器系统。该系统由PZT悬臂梁、弹性悬挂磁铁块、粘附于悬臂梁末端磁铁块及谐振器等组成,引入谐振器及磁铁可实现增加系统模态数量和非线性。基于此混合振动俘能器建立了改进型连续体机电耦合解析模型,并由龙格-库塔算法进行了求解。在此基础上,研制了振动俘能器原理样机,并搭建了实验系统,通过实验和解析评估方法完成了单一式和复合式俘能器性能比对和评估;研究表明,所研究的混合型振动俘能器相对常规振动能量俘集原理可实现较宽的频率范围及多模态振动能量俘集,且能量俘集效率明显提高,具有较好的应用前景。     

Energy policy shifts towards sustainable energy future for Malaysia

As a developing country, Malaysia’s prosperity and welfare depends heavily on having access to reliable and secure supplies of energy. As a result, the country’s future energy requirements have become a policy priority in recent years. Energy is essential for human life, and a secure and accessible supply of energy becomes important for the modern societies. Fossil fuels such as coal, oil, and natural gas are currently the world’s primary energy sources and continue to provide energy source to the world. These energy sources have depleted in reserves in recent years and they can also cause irreparably damage to the environment such as global warming and climate change. These environmental concerns can be addressed, to some extent, through more sustainable solutions such as the use of renewable energy resources. In Malaysia, the economic and environmental impacts of fossil fuels use have become hard to ignore. The government has introduced and implemented policy measures to address concerns surrounding the use of fossil fuels and to promote energy efficiency and renewable energy use. In this paper, we review the historical evolution of Malaysian energy policies and initiatives designed to secure diverse energy sources and avoid over-reliance on fossil fuels. In recent years, Malaysia has been catching up with global call to shift to renewable energy use and is now putting a focus on renewable energy in its future energy mix. The paper also discusses challenges and concerns over the future of sustainable energy of the country.     

Energy Harvesting Research: The Road from Single Source to Multisource

Energy harvesting technology may be considered an ultimate solution to replace batteries and provide a long‐term power supply for wireless sensor networks. Looking back into its research history, individual energy harvesters for the conversion of single energy sources into electricity are developed first, followed by hybrid counterparts designed for use with multiple energy sources. Very recently, the concept of a truly multisource energy harvester built from only a single piece of material as the energy conversion component is proposed. This review, from the aspect of materials and device configurations, explains in detail a wide scope to give an overview of energy harvesting research. It covers single‐source devices including solar, thermal, kinetic and other types of energy harvesters, hybrid energy harvesting configurations for both single and multiple energy sources and single material, and multisource energy harvesters. It also includes the energy conversion principles of photovoltaic, electromagnetic, piezoelectric, triboelectric, electrostatic, electrostrictive, thermoelectric, pyroelectric, magnetostrictive, and dielectric devices. This is one of the most comprehensive reviews conducted to date, focusing on the entire energy harvesting research scene and providing a guide to seeking deeper and more specific research references and resources from every corner of the scientific community.     

商场空调系统能耗评价与节能措施的研究

空调能耗是建筑能耗的主要部分,改善空调运行调节,能有效地提高能源利用率.本文提出了大型商场能耗评价方法,计算了能耗指数以分析能源利用率与节能潜力;并在此基础上,提出了空调系统的改进方案,优化运行管理,达到节能的目的.