harsh environment
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2022 ◽  
Vol 34 (1) ◽  
pp. 2270009
Xiaohu Hou ◽  
Xiaolong Zhao ◽  
Ying Zhang ◽  
Zhongfang Zhang ◽  
Yan Liu ◽  

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Tingzhong Wang ◽  
Lingli Zhu ◽  
Miaomiao Fu ◽  
Tingting Zhu ◽  
Ping He

Repetitive transients are usually generated in the monitoring data when a fault occurs on the machinery. As a result, many methods such as kurtogram and optimized Morlet wavelet and kurtosis method are proposed to extract the repetitive transients for fault diagnosis. However, one shortcoming of these methods is that they are constructed based on the index of kurtosis and are sensitive to the impulsive noise, leading to failure in accurately diagnosing the fault of the machinery operating under harsh environment. To address this issue, an optimized SES entropy wavelet method is proposed. In the proposed method, the optimized parameters including bandwidth and central frequency of Morlet wavelets are selected. Then, based on the wavelet coefficients decomposed using the optimized Morlet wavelet, the SES entropy is calculated to select the scales of wavelet coefficients. Finally, the repetitive transients are reconstructed based on the denoising wavelet coefficients of the selected scales. One simulation case and vibration data collected from the experimental setup are used to verify the effectiveness of the proposed method. The simulated and experimental analyses showed that the signal-to-noise ratio (SNR) of the proposed method has the largest value. Specifically, the SNR in the experimental analysis of the proposed method is 0.6, while that of the other three methods is 0.043, 0.0065, and 0.0045, respectively. Therefore, the result shows that the proposed method is superior to the traditional methods for repetitive transient extraction from the vibration data suffered from impulsive noise.

2021 ◽  
Prashant S. Alegaonkar ◽  
Vasant N. Bhoraskar ◽  
Sudha V. Bhoraskar

Polyimide (PI, PMDA-ODA, C22H11N2O5, Kapton-H), is a class of polymer, extensively used in microelectronics and space technology, due to its exceptional mechanical, dielectric, and chemical properties. In space, PI heat shield experiences a harsh environment of energetic electrons, ultra-violet radiation, and atomic oxygen, causing degradation and erosion. Radiation-assisted physicochemical surface modulations in PI, in view of understanding and reducing the degradation in laboratory-based systems, are discussed in the chapter. Strategies for the design and development of 2D, flat, and flexible electromechanical devices by swift heavy ion induced bulk modifications in PI are also described. Fabrication of a couple of such devices, including their performance analysis, is presented.

Eiji Yamamura

A summer high school baseball tournament is held every mid-summer in Koshien Stadium. “Koshien Baseball” is very popular in Japan; however, it faces the problem of extremely high temperatures during games. Thus, high school players are threatened by the harsh environment. For this reason, Internet surveys were conducted twice to purposefully engage the same individuals. Then, information on their views regarding the Koshien tournament before and after the provision of information regarding environmental change in Japan was gathered. Using data, this study examined how their views changed after having the information. Compared with the view before, it was found that (1) respondents were more likely to agree that the management rule of the Koshien tournaments should be altered to protect player’s health, and (2) the impact of providing information is larger for female respondents, young people, and highly educated respondents.

Solar Energy ◽  
2021 ◽  
Vol 230 ◽  
pp. 1070-1084
Sara Lakhouil ◽  
Sofia Boukheir ◽  
Abdelouahed Chbihi ◽  
Sanae Naamane

2021 ◽  
Muhabaw Amare Alebachew ◽  
Anil Kumar Nayak ◽  
Amalendu Patnaik

Abstract this paper is studied on a microstrip based pressure sensor for harsh environment applications which can sensing at a distance. A microstrip based pressure sensor for harsh environment was investigated with good results by using Rogers’s 3210 substrate material with a dielectric constant of 10.2, 1.28mm thickness and 2.4 GHz resonant frequency, and also both the patch side and the ground side are made from copper metal. The simulation of a proposed antenna was designed and tested by using HFSS software, the result of the designed antenna’s resonance frequency is inversely proportional with the displacement gap of the reflection plate and an antenna. The operating principles of this sensor, when a pressure (load) is applied on the reflection metal plate, the distance will decrease from the reflection plate and the resonant frequency will increase. Therefore, the applied pressure (load) can determined by measuring the changing resonance frequencies. Certainly, the simulation and the experimental results of performances and validates are clearly discussed.

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Jing Zhang ◽  
Yajing Hu ◽  
Hongliang Li

For smart city wireless sensing network construction needs, a network positioning algorithm based on genetic algorithm is proposed. The genetic algorithm uses a real number encoding, and the positioning model is constructed by analyzing the communication constraint between unknown nodes and a small amount of anchor nodes and constructs the positioning model, and the model is solved. The results show that when the ranging error is 50%, the positioning error is only increased by approximately 15% compared to the nonranging error. In a more harsh environment, if the ranging error is equal to the node wireless range, the ranging error is 100%, and the positioning error and the positioning ratio are not significantly changed. The scheme obtained by this algorithm can be well approarded with an ideal limit. In the case where the sensor node is given, the algorithm can obtain the maximum coverage.

2021 ◽  
Joseph Shepherd

<p>It may be considered that architecture does not as a discipline, acknowledge the changes a building will go through after construction completion. Therefore, weathering of materials occurs without direction forcing a building to degrade over time rather than mature. We may accept that materials have a given lifespan and that it is simply a question of time before that material is no longer suitable for its original use. However, the impermanence of materials through weathering need not be considered a negative element throughout the life of a building. It may give us the impression that we can grasp the effects of time in a tangible way through its visual expressions, reminding us of our own place in the cycle of time. This thesis was design led by firstly producing material experiments, and going on site to understand the conditions of weathering on materials. This lead to a number of questions – firstly, may architecture direct its own visual expression of time through embracing the inevitable process of weathering within its materials and site? Can these actualizations of time documenting the events of a buildings life promote the build up of personal memory between the user and the architecture they experience? These questions were tested through the design of temporary research accommodation units located at Te Raekaihau Point on the south coast of Wellington. Being an extremely harsh environment, the full force of a weathered trace could be illustrated. Through design, the idea of architecture as an evolving image was explored. The contrasting material time frames of concrete and wood were understood in their relation to one another and how one may act as a framework for the other. Concrete surfaces expressed positive and negative detail, directing the weather to enhance certain patterns over time. The organic nature of timber was interpreted throughout the site with varied levels of exposure. Original traces of weather on site were used to understand future interpretations. These traces influenced material placement, orientation and gave an understanding of the processes that will affect architecture in time. Accepting that no material is permanent, certain details explored the idea that one materials death may bring about the birth of another. Over time, a timber walkway connecting two areas of the site was designed to erode, revealing a concrete stairway hidden beneath. These design considerations lead to the conclusion that architecture must be considered over time, with careful consideration of the natural forces that will affect its development. A site analysis does not occur in one visit, it must be a more thorough process considering all aspects that affect materials in time and how best to work with these inevitable facts as opposed to against them. This will result in a building capable of capturing the actualisations of time promoting memory through the weathered trace.</p>

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