Experiment-simulation Study on Noise Reduction of Cylinder Shell with Horn Helmholtz Resonator

This paper focuses on the noise reduction of the cylindrical structure at low frequency (130 Hz-180 Hz). The low-frequency noise response spectrum in the cylindrical cavity is obtained by using the Helmholtz resonator (HR) to reduce the noise peak amplitude. The acoustic simulation software Virtual.Lab is used to establish the finite element model of the cylindrical shell with HR, and to obtain the low-frequency acoustic response in the cylindrical cavity. The simulation model is validated by the experimental results. Then, the influence of installation position, the number of installed resonators and the resonators with different resonance frequencies in the cylindrical cavity are discussed. The results indicate that both the noise reduction band and peak amplitude are increased by installing the HR\u27s on the cylinder shell. The noise reduction of the cylinder shell with HR installed on the upper position is larger than other situations. As the number of resonators increased, the frequency range of the noise reduction in the cylindrical cavity gradually increases, and the noise reduction of the cylinder cavity increases first and then decreases

Addressing Wealth Inequality Problem in Blockchain-Enabled Knowledge Community with Reputation-Based Incentive Mechanism

An increasing number of online knowledge communities have started incorporating the cut-edge FinTech, such as the tokenbased incentive mechanism running on blockchain, into their ecosystems. However, the improper design of incentive mechanisms may result in reward monopoly, which has been observed to harm the ecosystems of exiting communities. This study is aimed to ensure that the key factors involved in users’ reward distribution can truly reflect their contributions to the community so as to increase the equity of wealth distribution. It is one of the first to comprehensively balance a user’s historical and current contributions in reward distribution, which has not received sufficient attention from extant research. The simulation analysis demonstrates that the proposed solution of amending the existing incentive mechanism by incorporating a refined reputation indicator significantly increases the equity of rewards distribution and effectively enlarges the cost of achieving reward monopoly

The gon-1 Gene Is Required for Gonadal Morphogenesis in Caenorhabditis elegans

AbstractIn wild-type Caenorhabditis elegans, the gonad is a complex epithelial tube that consists of long arms composed predominantly of germline tissue as well as somatic structures specialized for particular reproductive functions. In gon-1 mutants, the adult gonad is severely disorganized with essentially no arm extension and no recognizable somatic structure. The developmental defects in gon-1 mutants are limited to the gonad; other cells, tissues, and organs appear to develop normally. Previous work defined the regulatory “leader” cells as crucial for extension of the gonadal arms (J. E. Kimble and J. G. White, 1981, Dev. Biol. 81, 208–219). In gon-1 mutants, the leader cells are specified correctly, but they fail to migrate and gonadal arms are not generated. In addition, gon-1 is required for morphogenesis of the gonadal somatic structures. This second role appears to be independent of that required for leader migration. Parallel studies have shown that gon-1 encodes a secreted metalloprotease (R. Blelloch and J. Kimble, 1999, Nature 399, 586–590). We discuss how a metalloprotease may control two aspects of gonadal morphogenesis

A Fault Diagnosis Scheme for Gearbox Based on Improved Entropy and Optimized Regularized Extreme Learning Machine

The performance of a gearbox is sensitive to failures, especially in the long-term high speed and heavy load field. However, the multi-fault diagnosis in gearboxes is a challenging problem because of the complex and non-stationary measured signal. To obtain fault information more fully and improve the accuracy of gearbox fault diagnosis, this paper proposes a feature extraction method, hierarchical refined composite multiscale fluctuation dispersion entropy (HRCMFDE) to extract the fault features of rolling bearing and the gear vibration signals at different layers and scales. On this basis, a novel fault diagnosis scheme for the gearbox based on HRCMFDE, ReliefF and grey wolf optimizer regularized extreme learning machine is proposed. Firstly, HRCMFDE is employed to extract the original features, the multi-frequency time information can be evaluated simultaneously, and the fault feature information can be extracted more fully. After that, ReliefF is used to screen the sensitive features from the high-dimensional fault features. Finally, the sensitive features are inputted into the optimized regularized extreme learning machine to identify the fault states of the gearbox. Through three different types of gearbox experiments, the experimental results confirm that the proposed method has better diagnostic performance and generalization, which can effectively and accurately identify the different fault categories of the gearbox and outperforms other contrastive methods.</p

Elephant Culture Matter for China’s Asian Elephants Conservation

Traditional anthropogenic impacts such as hunting, using as war-elephant, trading of ivory, paying tribute to the imperial court and so on, were once thought to be directly responsible for the rapid decline of Asian elephants in China. But in Yunnan Province, China, a unique human factor such as the traditional elephant culture of local ethnic minorities, is an important factor in the conservation of Asian elephants. In these areas, we investigated by means of village interviews, field surveys and data collection, the results show that the elephant culture of ethnic minorities has a great impact on people's thoughts and behaviors, these traditional culture and belief (that mean taking elephant as the God, holding elephant as a belief, worshipping elephant and praise it) urges people to actively protect elephants and avoid more human-elephant conflicts. To enhance the public awareness of Asian elephant conservation, the Chinese Government or international environmental organizations should give higher attention and support to these elephant cultures.

Research on the Interventional Effects of Stress Psychological Nursing Method on Patients with Acute Coronary Syndrome

Objective: To investigate the interventional effects of stress psychological nursing method on patients with acute coronary syndrome (ACS). Methods: 100 patients with ACS who were rescued in the emergency department and department of cardiology of our hospital between January 2017 and December 2017 were enrolled. According to the random number method, the patients were divided into control group and observation group. There were 50 patients in each group. The interventions were given as routine nursing and stress psychological nursing, and the results of the two interventions were compared. Results: Before the intervention, there was no difference in the general clinical data between the control group and the observation group, which was not statistically signifcant; after the intervention for anxiety and depression, average hospitalization time, and off-bed time, the difference in data between the control group and the observation group on anxiety and depression was statistically signifcant. Moreover, the values of all the observation groups were lower than those of the control group. Conclusion: Applying stress psychological nursing method to the nursing of the patients with ACS can signifcantly improve their anxiety and depression, which signifcantly improves their quality of life, and enables the patients to better grasp the relevant health knowledge, at the same time, it obtains good intervention effects, which is worth promoting in a wider clinical scope