Bridge health evaluation has been a challenging issue due to high assessment errors with imbalanced and insufficient monitoring data of correlative bridge monitoring factors. We propose a data augmentation model as the preprocessing of bridge health evaluation to expand existing monitoring data of bridge monitoring factors on the basis of generative adversarial nets (GAN), named as information-GAN (InfoGAN)-multi-scale-filtering. In this model, new data of bridge monitoring factors are produced by the InfoGAN-based model with regards to learning coupling relations among bridge monitoring factors. To resolve generalization issues from the parameter matrix in traditional InfoGAN, we improve the discriminator with spectral normalization to optimize the weight training process. To deal with the instability of InfoGAN performance, which creates defective samples, a multi-scale filtering scheme is designed to obtain effective samples from the InfoGAN-based model. The scheme picks credible samples from both quantitative and qualitative aspects with the multiple scale filtering procedure. Additionally, inherent properties of bridge monitoring factors (e.g. distributions) are discovered within the generation process. Finally, filtered data are mixed into raw monitoring data to train classifiers. Simulation results imply that the proposed model performs effectively in data generation of real-world bridge monitoring factors and improves the performance of bridge health evaluation.
Nuclear power generation has become an increasingly attractive alternative in the global power market due to growing demand for electric power, increasing global competition for fossil fuels, concern over greenhouse gas emissions and their potential impact on climate change, and the desire for energy independence. Nuclear energy plays an integral role in providing carbon free energy for sustainable development of global electric power generation. Assuring the protection of people and the environmental is a prime consideration in the design, construction, and operation of nuclear power plants. Potential environmental and safety concerns must be carefully evaluated and addressed. In order to assure that the nuclear power plant designs are sufficiently robust, the U.S. Nuclear Regulatory Commission (USNRC) requires that applicants for early site permits (ESP) and construction/operating licenses (COL) identify the most severe natural phenomena historically reported for the site and surrounding area to ensure sufficient design margin exists, considering the limited accuracy, quantity, and time in which the associated data has been collected. Because these permits are valid for a period up to 40 years, the potential impacts of climate change on the severity of natural phenomena, as it relates to the design basis and nuclear safety and environmental impacts are of increasing interest. Although no conclusive evidence or consensus of opinion is available on the long-term climatic changes resulting from human or natural causes, the USNRC has requested that climate change forecasts be considered for their potential affecting the most severe natural phenomena. The specific subject areas of concern include: • Extreme temperature and extreme precipitation (liquid & frozen) statistics – review 100 years of data around the site versus a review of the previous 30 years of data. • Extreme wind/basic wind speed – review previous 100 years of tropical cyclone data (including hurricanes) in the site vicinity versus previous 30 years of data. • Tornado – review of frequency and intensity trends and forecasts. • Drought – review of water availability / water supply during drought conditions and drought of record. • Stagnation Potential – review of conditions that would result in restrictive dispersion of greenhouse gas emissions. This paper examines the challenges and constraints in identifying and developing appropriate design- and operating-basis site/regional meteorological conditions while accounting for potential climate change during preparation of an ESP and/or COL. Because there is no regulatory guidance or quantitative acceptance criteria currently available, the methodology used to address climate change in a recent issued ESP will be discussed as an example.
Aiming at the problem of excessive mechanical loss of the conventional vane compressor, this paper proposes a novel vane compressor structure. This compressor can significantly reduce the mechanical frictional loss through converting sliding friction between vane tip and cylinder into rolling friction by using a rolling bearing. The structure and operation principle are introduced in this paper, and mechanical friction loss calculation models of these two kinds of compressor are theoretically analyzed. The results show that mechanical loss of the novel vane compressor can be reduced by nearly 38% under the same working conditions. At the same time, the actual tested results indicated that the total power consumption of compressor decreased 160.1W (6.89%), and the COP increased by 11.89%.
As an aftermath of the natural disasters affecting the Fukushima Daiichi nuclear power plants in Japan, there has been great attention to provide assurance of safety of nuclear power plants around the world. Accordingly, many countries are requiring “stress tests” for their plants to assess the ability to withstand disaster scenarios for which they were not originally designed. Additional efforts are underway to capture lessons learned related to the operation of critical or major systems. Each operator and each country’s regulatory authority may be at different levels of completion for these activities. However, effects on non-safety related or peripheral systems have not been specifically addressed as standalone items or in an integrated systems approach. This paper seeks to produce an initial assessment of vulnerable systems, structures or components of non-safety related areas that may become critical to the safe operation of a nuclear plant or to the first steps to maintain stability of the plant during a postulated beyond design basis event. The same assessment is valid for events of significant magnitude, or for events affecting the entire site or region, even if a plant’s design basis is not exceeded. The initial assessment is based on widespread events, such as at the Fukushima Daiichi station, with focus on large nuclear power reactors. Certain peripheral plant systems support plant operators and staff or emergency responders such as by affording communication or physical access to plant areas. Other peripheral systems support plant operation or recovery, for example provision of diverse power supply or cooling means. Passive components common to multiple systems such as cables and piping are also assessed. Once vulnerable systems, structures or components are identified, various modifications or mitigation approaches will be discussed.
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