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The rapid development of advanced metering infrastructure provides a new data source—building electrical load profiles with high temporal resolution. Electric load profile characterization can generate useful information to enhance building energy modeling and provide metrics to represent patterns and variability of load profiles. Such characterizations can be used to identify changes to building electricity demand due to operations or faulty equipment and controls. In this study, we proposed a two-path approach to analyze high temporal resolution building electrical load profiles: (1) time-domain analysis and (2) frequency-domain analysis. The commonly adopted time-domain analysis can extract and quantify the distribution of key parameters characterizing load shape such as peak-base load ratio and morning rise time, while a frequency-domain analysis can identify major periodic fluctuations and quantify load variability. We implemented and evaluated both paths using whole-year 15-minute interval smart meter data of 188 commercial office building in Northern California. The results from these two paths are consistent with each other and complementary to represent full dynamics of load profiles. The time- and frequency-domain analyses can be used to enhance building energy modeling by: (1) providing more realistic assumptions about building operation schedules, and (2) validating the simulated electric load profiles using the developed variability metrics against the real building load data.

Ancillary services and other interconnected services are important especially in a competitive operation environment. Since these services are costs related, they should be allocated in order to send the correct price signal to market participants. An average sensitivity method is proposed for allocating services to simultaneous transactions. It can provide results close to power flow-based methods, while requiring as little computational time as traditional sensitivity-based approaches. Except for rare cases, it satisfies the requirement of allocation quantity, allocation ratio, and application feasibility. Test results indicate that the average sensitivity method is a successful allocation algorithm.

上下方向に単調和振動をする水平面上におかれた非反発性物体の運動解析を振動加速度の大きい範囲に対してまず行なった。次に二れの延長として個々のものは反発性てある鍋球で形成された層の運動について検討した。この場合には, 衝撃を受けて鋼球群の充てん構造が変化する二とおよび反発によってランダムに運動をする層上部の鋼球群が下部層の運動を抑制するという働きによって, 層の大部分は規則正しい運動をすることが認められた。そこでこれに対する上下方向の運動方程式として非反発性物体の場合をも包含したかたちの式を提示し, 実教によりこれを確かめた。このよ5な検討結果は主として振動ミルによる粉砕現象を検討するさいの基礎として役立つものと思われる。

Abstract The anodic polarization behaviour of iron whisker crystals was investigated in a neutral solution with or without the presence of chloride ion, with special attention to the role played by surface defects in the dissolution, the passivation and the pitting of iron. The grown whisker used was substantially dislocation-free and the defect density was varied by twisting of whisker. With increase in the angle of twisting, the anodic dissolution current increased in a chloride-free solution, whereas it decreased in a chloride-containing solution. The defect density in the substrate had no remarkable effect on passivation but the thickness of the passive film was slightly increased on twisted whiskers. The anodic polarization curve of a grown whisker in a chloride-containing solution did not exhibit a distinct pitting potential. By twisting of whisker, however, a current rise due to pitting appeared on the polarization curve and the apparent pitting potential shifted in the negative direction with increasing angle of twisting. Potentiostatic polarization experiments in a chloride-containing solution showed the emergence of random current pulses due to the breakdown of passive film and to repassivation. It is highly probable that the breakdown of the passive film occurs at the physical or chemical inhomogeneities in the passive film not associated with dislocation termini but that pitting occurs only when the breakdown occurs at emergent dislocation sites.

AbstractRevolutionary changes in energy storage technology have put forward higher requirements on next‐generation anode materials for lithium‐ion battery. Recently, a new class of materials with complex stoichiometric ratios, high‐entropy oxide (HEO), has gradually emerging into sight and embracing the prosperity. The ideal elemental adjustability and attractive synergistic effect make HEO promising to break through the integrated performance bottleneck of conventional anodes and provide new impetus for the design and development of electrochemical energy storage materials. Here, the research progress of HEO anodes is comprehensively reviewed. The driving force behind phase stability, the role of individual cations, potential mechanisms for controlling properties, as well as state‐of‐the‐art synthetic strategies and modification approaches are critically evaluated. Finally, we envision the future prospects and related challenges in this field, which will bring some enlightening guidance and criteria for researchers to further unlock the mysteries of HEO anodes.image

Control methods based on global positioning systems (GPS) are reported in multiple literatures recently, which achieve a fixed frequency operation of the microgrid and therefore has the tremendous benefit that any problems related to frequency instability are eliminated. However, the possible interruption of GPS timing signals may cause current circulating and finally leads to instability of the microgrid, yet it is largely neglected in literatures. This paper presents an angle synchronizing mechanism which utilizes the timing signal from GPS satellites and an auxiliary frequency droop loop to ensure synchronization during GPS offline events. Smooth transfer is guaranteed between primary and auxiliary control loops with discrete control architecture. Also, to allow microgrid using GPS-based control to work in tandem with the bulk power system or another frequency droop microgrid, an extra synchronization algorithm is proposed. The viability and performance of the proposed control structure is validated by case studies.

AbstractShipbuilding is an energy-intensive industrial sector that produces a significant amount of waste, pollution and air emissions. However, the International Maritime Organization concentrates only on reducing emissions during the operational phase. In order to completely phase out emissions from the shipping industry, a life-cycle approach must be taken. The study implemented the proposed transdisciplinary energy management framework in a Bangladeshi shipyard. The framework aims to support shipyard decision makers in making rational and optimized decisions to make shipyards sustainable, while maintaining good product quality and reducing relative cost. This is achieved by applying the Fuzzy Analytical Hierarchy Process and Fuzzy Order of Preference by Similarity to Ideal Solution methods to identify optimal solutions. In addition to making shipyards more sustainable, the framework can enhance both the business and socio-economic prospects of the shipyard and promote the reputation of the shipyard and improve its competitiveness and, in line with this, lead to the promotion of nationally determined contributions under the Paris Agreement for States. The implementation of the framework shows that the political and legal discipline, the social criteria and the implementation of ISO 14001 and cyber security were the most important criteria and options for the yard's decision makers.

The paper comprises a systematic experimental investigation into the influence of AC test source parameters on the leakage current pulses, voltage fluctuations and flashover voltages of polluted insulators. The test techniques include both salt-and clean-fog methods, while the test insulators comprise long-rod and cap and pin strings of different lengths as well as support columns.

A fundamental objective of rangeland managers all over the world is to take measures to ensure that the rangeland being managed stays away from irreversible states in which it provides little or no consumptive and non-consumptive services to humans. Nevertheless, despite a manager's best attempts, the rangeland under study may still hit an irreversible state. Accordingly, given a particular management regime, it is useful to know the length of time taken to hit an irreversible state. In this paper, we conduct a theoretical analysis of this hitherto unstudied question. We first provide a probabilistic description of two range management regimes. Next, we calculate the mean time until an irreversible state is hit for both these regimes. Finally, we provide a numerical example to demonstrate the working of our model and then we discuss the ramifications of our findings for rangeland management in general.