Health status assessment of axial piston pump under variable speed

The axial piston pump usually works under variable speed conditions.It is important to evaluate the health status of the axial piston pump under the variable speed condition.Aiming at the characteristic signals obtained under different wear levels of the port plate,a feature signal extraction method under variable speed conditions is proposed.Firstly,the combination of complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)energy spectrum and fast spectral kurtosis principle is used to accurately extract the intrinsic mode function(IMF)component containing the sensitive information of the degraded feature.Then,the aspect ratio analysis method of the angle domain variational mode decomposition(VMD)is used to process the feature index containing the sensitive information of the degraded feature.In order to evaluate the health status of the axial piston pump under variable speed,the vibration reliability analysis method for axial piston pump based on Weibull proportional failure rate model is proposed.The experimental results show that the proposed method can accurately evaluate the health status of the axial piston pump.

Nutrients distribution and trophic status assessment in the northern Beibu Gulf, China

Using historical and 2010 field data, the distribution of nutrients in the northern Beibu Gulf of China is described. There was a decreasing trend in the concentration of nutrients from the north coast to offshore waters of the northern Beibu Gulf, reflecting the influence of inputs from land-based sources. High concentrations of dissolved inorganic nitrogen （DIN） and phosphate （PO4-P） occurred mainly at Fangchenggang Bay, Qinzhou Bay, and Lianzhou Bay. Four different methods were used to assess eutrophication. The trophic status of the Beibu Gulf was characterized using the single factor, Eutrophication index （El）, Trophic index （TRIX） and Assessment of Estuarine Trophic Status （ASSETS） methods. Based on nutrient concentrations, 73.9% of DIN and 26.7% of PO4-P samples exceeded the fourth grade Seawater Quality Standard of China. Eutrophication index values varied widely, but higher levels of eutrophication were generally found in bays and estuaries. TRIX values ranged from 2.61 to 7.27, with an average of 4.98, indicating a mesotrophic and moderately productive system. A positive correlation between TRIX and harmful algal species richness and abundance was observed. The ASSETS model evaluates eutrophication status based on a Pressure-State-Response approach, including three main indices： influencing factors, overall eutrophic condition, and future outlook. The Beibu Gulf was graded as moderate using ASSETS. The single factor and Chinese nutrient index methods were considered inadequate for the assessment of trophic status. TRIX can be used as an indicator of trophic state and ASSETS showed good potential to assess eutrophication. The results of TRIX and ASSETS depend on threshold values. To establish these values, further research is required within the northern Beibu Gulf.

Forest status assessment in China with SDG indicators based on high-resolution satellite data

To assess the status and change trend of forest in China,an indicator framework was developed using SDG sub-indicators.In this paper,we propose an improved methodology and a set of workflows for calculating SDG indicators.The main modification include the use of moderate and high spatial resolution satellite data,as well as state-of-the-art machine learning techniques for forest cover classification and estimation of forest above-ground biomass(AGB).This research employs GF-1 and GF-2 data with enhanced texture information to map forest cover,while time series Landsat data is used to estimate forest AGB across the whole territory of China.The study calculate two SDG sub-indicators:SDG_(15.1.1) for forest area and SDG_(15.2.1) for sustainable forest management.The evaluation results showed that the total forest area in China was approximately 219 million hectares at the end of 2021,accounting for about 23.51%of the land area.The average annual forest AGB from 2015 to 2021 was estimated to be 105.01Mg/ha,and the overall trend of forest AGB change in China was positive,albeit with some spatial differences.

Spatial distribution of ecological security status assessment of West-Liaohe River based on geographic information system

Eco-security assessment is a hot research area in resource and environmental science,which involves data with much spatial,non-linear,and random features.Geographic information system(GIS),as a useful tool to analyze and manage spatial information,has a superior advantage in this field.A case study in the western part of the Liaohe River featuring a method of eco-security spatial differences(ESSD)based on GIS is developed in this paper.The method includes four steps:1)developing the pressure-state-response(P-S-R)framework with site data;2)digitizing West-Liaohe River and setting its GRID database of eco-security assessment indicators;3)figuring out the relative membership degree(RMD)of eco-security indicators by using the analytical hierarchy process with the weight of indicator;4)classifying the security zone and mapping the assessment result of eco-security status in grid by GIS method of assigning and clustering.The visual spatial differences of eco-security based on GIS enables decision makers to know the status of eco-security better in making policies for achieving sustainability.

Health Status Assessment for New Urban Rail Vehicle Traction Systems Based on Cross Entropy and SVM

A health status assessment method based on cross entropy and support vector machine(SVM)is proposed for the new urban rail vehicle traction systems.First,an index system for health assessment of the traction system is established,and combined weights of the index layer are obtained via cross entropy.Then,an SVM assessment model considering actual operating data and each status level of the traction system is established.Finally,the model is simulated in Matlab to obtain assessment results.The results indicate that the proposed method can provide the health status information of the traction system intuitively and complete the health status assessment of the traction system of the new urban rail vehicle effectively,by exploiting the traction system’s layered analysis model.The health status can be assessed accurately and reliably by adopting the cross entropy theory and SVM theory.

Study on Assessment of Mine Environments

Mine environmental evaluation is the key to mine environmental study. On the basis of the characteristics of the mine environmental problems, they are classified into （1） three wastes problem, （2） ground distortion, （3） contradiction among mine drainage, water supply, ecological environment, （4） desertification, and （5） soil erosion. The evaluation is the basis of mine environmental problem classification and investigation, mine environmental rehabilitation, and the information system constructed can be used for subsequent research of evaluation techniques. A synthetic assessment of the 5 kinds of mine environmental problems can be divided into single-factor or multi-factor synthetic assessments; while by the viewpoint of time, the mine environmental assessment can be classified as the historical assessment, the current status assessment and the forecasting assessment.

COVID-19 and liver dysfunction:What nutritionists need to know

The coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus-2 has brought serious challenges for the medical field.Patients with COVID-19 usually have respiratory symptoms.However,liver dysfunction is not an uncommon presentation.Additionally,the degree of liver dysfunction is associated with the severity and prognosis of COVID-19.Prevention,diagnosis,and treatment of malnutrition should be routinely recommended in the management of patients with COVID-19,especially in those with liver dysfunction.Recently,a large number of studies have reported that nutrition therapy measures,including natural dietary supplements,vitamins,minerals and trace elements,and probiotics,might have potential hepatoprotective effects against COVID-19-related liver dysfunction via their antioxidant,antiviral,anti-inflammatory,and positive immunomodulatory effects.This review mainly focuses on the possible relationship between COVID-19 and liver dysfunction,nutritional and metabolic characteristics,nutritional status assessment,and nutrition therapy to provide a reference for the nutritionists while making evidence-based nutritional decisions during the COVID-19 pandemic.

Assessment of iodine nutritional status of people in Qinghai Province after the content of salt iodine decreased

Objective To understand the iodine nutritional status of people in Qinghai Province after implementation of new standard of salt iodine,and provide the basis for prevention and control of iodine deficiency disorders.Methods The monitoring data of 2011 and 2014

Development and preliminary application of a method to assess river ecological status in the Hai River Basin,north China

The river ecosystem in the Hai River Basin（HRB）, an important economic region in China, is seriously degraded. With the aim of river restoration in the HRB, we developed a method to assess the river＇s ecological status and conducted a preliminary application of the method.The established method was a predictive model, which used macroinvertebrates as indicator organisms. The river＇s ecological status was determined by calculating the ratio of observed to expected values（O/E）. The method included ecoregionalization according to natural factors, and the selection of reference sites based on combinations of habitat quality and macroinvertebrate community. Macroinvertebrate taxa included Insecta,Crustacea, Gastropoda, and Oligochaeta, with 39 families and 95 genera identified in the HRB. The HRB communities were dominated by pollution tolerant taxa, such as Lymnaeidae, Chironomus, Limnodrilus, Glyptotendipes, and Tubifex. The average Shannon–Wiener index was 1.40 ± 0.5, indicating a low biodiversity. In the river length of 3.31 × 10^4 km, 55% of the sites were designated poor, with a bad ecological status. Among nine secondary river systems, Luan and Zi-ya had the best and worst river conditions,respectively. Only 17 reference site groups were selected for river management in the 41 ecoregions examined. This study lays the foundation for river restoration and related research in the HRB, and we anticipate further developments of this novel method.