Application of Instantaneous Rotational Speed to Detect Gearbox Faults Based on Double Encoders

Considerable studies have been carried out on fault diagnosis of gears, with most of them concentrated on conventional vibration analysis. However, besides the complexity of gear dynamics, the diagnosis results in terms of vibration signal are easily misjudged owing to the interference of sensor position or other components. In this paper, an alternative gearbox fault detection method based on the instantaneous rotational speed is proposed because of its advantages over vibration analysis. Depending on the timer/counter-based method for the pulse signal of the optical encoder, the varying rotational speed can be obtained e ectively. Owing to the coupling and meshing of gears in transmission, the excitations are the same for the instantaneous rotational speed of the input and output shafts. Thus, the di erential signal of instantaneous rotational speeds can be adopted to eliminate the e ect of the interference excitations and extract the associated feature of the localized fault e ectively. With the experiments on multistage gearbox test system, the di erential signal of instantaneous speeds is compared with other signals. It is proved that localized faults in the gearbox generate small angular speed fluctuations, which are measurable with an optical encoder. Using the di erential signal of instantaneous speeds, the fault characteristics are extracted in the spectrum where the deterministic frequency component and its harmonics corresponding to crack fault characteristics are displayed clearly.

nsights into battles between Mycobacterium tuberculosis and macrophages

As the first line of immune defense for Mycobacterium tuberculosis （Mtb）, macrophages also provide a major habitat for Mtb to reside in the host for years. The battles between Mtb and macrophages have been constant since ancient times. Triggered upon Mtb infection, multiple cellular pathways in macrophages are activated to initiate a tailored immune response toward the invading pathogen and regulate the cellular fates of the host as well. Toll-like receptors （TLRs） expressed on macrophages can recognize pathopatterns （PAMPs） on Mtb and mediate the production of immune-regulatory cytokines such as tumor necrosis factor （TNF） and type I Interferons （IFNs）. In addition, Vitamin D receptor （VDR） and Vitamin D-1- hydroxylase are up-regulated in Mtb-infected macrophages, by which Vitamin D participates in innate immune respon- ses. The signaling pathways that involve TNF, type I IFNs and Vitamin D are inter-connected, which play critical roles in the regulation of necroptosis, apoptosis, and autophagy of the infected macrophages. This review article summarizes cur- rent knowledge about the interactions between Mtb and macrophages, focusing on cellular fates of the Mtb-infected macrophages and the regulatory molecules and cellular pathways involved in those processes.

复杂性–稳定性研究:数学模型的进展

对自然生态系统的观察给人们以复杂的群落更稳定的直观印象,但数学模型却得出了截然相反的结论。这一"悖论"使得复杂性–稳定性研究自20世纪70年代以来成为长期的热点。本文对这一领域的数学模型研究进行简要综述。首先对这一论题进行概念剖析,然后将各类模型分为线性和非线性两大类,前者即群落矩阵法,后者包括相互作用矩阵法、复杂网络数值模拟法和食物网构件动力学法。它们分别基于不同的群落构建方法和稳定性判断标准,探求各物种是如何相互作用并实现共存的。总体而言,在随机构建的群落模型中,多样性和连接度的增长不利于系统稳定;而在更接近真实自然群落的模型中,相互作用方式、网络拓扑结构、相互作用强度分布等方面的机制提供了稳定效应,按此组织的生态网络可达到很高的复杂度。然而,复杂性–稳定性的研究还远未结束,当前的模型仍不足以反映自然群落中的复杂相互作用,稳定性的概念也有待拓展。对这一议题的深入研究在生态学理论和生态系统管理实践方面都具有重大价值。

Baseline Characteristics and Treatment Patterns of the Patients Recruited to the China Registry of Hepatitis B

Background and Aims: Chronic hepatitis B virus(HBV)in-fection remains a major public health problem globally.Here,we describe the baseline characteristics and treatment pro-files of HBV-infected patients recruited to the China Registry of Hepatitis B.Methods: Inclusion criteria were patients with different stages of chronic HBV infection and complete key data.Exclusion criteria were patients with hepatocellular car-cinoma.The baseline clinical,laboratory and treatment pro-files were analyzed.Results: Finally,40,431 patients were included.The median age was 43 years,with 65.2%being men and 51.3%being positive for hepatitis B e antigen(HBeAg).The most common initial diagnosis was chronic hep-atitis B(81.0%),followed by cirrhosis(9.3%),inactive carrier of hepatitis B surface antigen(HBsAg)(6.7%),and immune tolerant phase of hepatitis B infection(3.0%).Among the 21,228 patients who were on treatment,88.0%,10.0%and 2.0%received nucleos(t)ide analogues(NAs),interferon or combination of NAs and interferon,respectively.The propor-tion of patients who received preferred NAs(entecavir or te-nofovir disoproxil fumarate)had increased from 13.5%in 2003 to 79.7%in 2016.Conclusions: We concluded that middle-aged men accounted for most of the patients with chronic hepatitis B in this cross-sectional study.About half of the patients were HBeAg-positive.NAs were the most com-monly used therapy,and use of the preferred NAs had steadily increased in the past decade.

Tacholess order-tracking approach for wind turbine gearbox fault detection

Monitoring of wind turbines under variablespeed operating conditions has become an important issue in recent years. The gearbox of a wind turbine is the most important transmission unit; it generally exhibits complex vibration signatures due to random variations in operating conditions. Spectral analysis is one of the main approaches in vibration signal processing. However, spectral analysis is based on a stationary assumption and thus inapplicable to the fault diagnosis of wind turbines under variable-speed operating conditions. This constraint limits the application of spectral analysis to wind turbine diagnosis in industrial applications. Although order-tracking methods have been proposed for wind turbine fault detection in recent years, current methods are only applicable to cases in which the instantaneous shaft phase is available. For wind turbines with limited structural spaces, collecting phase signals with tachometers or encoders is difficult. In this study, a tacholess order-tracking method for wind turbines is proposed to overcome the limitations of traditional techniques. The proposed method extracts the instantaneous phase from the vibration signal, resamples the signal at equiangular increments, and calculates the order spectrum for wind turbine fault identification. The effectiveness of the proposed method is experimentally validated with the vibration signals of wind turbines.

Social-ecological transformations of Inner Mongolia:a sustainability perspective

Introduction:Sustainability requires the reconciling of human needs with the healthy natural ecosystem,which should be achieved within the grand course of industrialization and modernization.Systematic transitions on demography,economy,technology,and institutions are required,while different civilizations may take their respective paths.In this study,we analyze the social-ecological transitions of Inner Mongolia Autonomous Region of China during the past century,focusing on major changes in its environmental,demographic,and socioeconomic conditions.Results:A two-level social-ecological system analysis framework was proposed,and four stages of transition were identified:traditional nomadism,primitive industrial civilization,collectivization era,and economic reform/opendoor policy era.Our analysis showed that Inner Mongolia has made great achievements in its socioeconomic domains but is faced with numerous challenging environmental problems.Overconsumption of resources and failure to curtail ecological degradation may lead to a trap of unsustainability.Conclusions:However,the slowing-down population growth,improvements of the economic structure,and many new sustainability initiatives and strong support from the central government together give hope for a sustainable future of the region.

Klebsiella pneumoniae NdpA suppresses ERK pathway-mediated host early inflammatory responses and is degraded through the ubiquitin-proteasome pathway

Klebsiella pneumoniae （KP） pathogen causing commun infections. When the host is an important opportunistic ty-acquired and nosocomial is immunocompromised, the pathogen would infect the host and cause diseases, such as pneumoniae, sepsis, liver abscess, meningitis, urinary tract inflammation and wound infection （Karaiskos et al., 2016; Park et al., 2015）. The phenomenon that K. pneumoniae has a preference to infect immunocompromised populations, especially seniors suggests that the outcomes of K. pneumoniae infection depend on the pathogen-host interactions, but up to now, the molecular mechanisms underlying K. pneumoniae-host interactions remain largely unknown.

Optimal cash holding decision with uncertain control

The decision-making of cash holdings is very important for the daily operation of enterprises.This present paper tries to establish uncertain optimal cash holding models with the constraint of safe cash holding area,and discusses the solutions of the models by establishing Lagrange function under KKT condition.On the one hand,this paper enriches the existing cash holding models,on the other hand,it is also a comprehensive discussion on the application of uncertainty theory in cash holding management.