Study of accelerated aging of 15 kv XLPE and EPR cable insulation by switching impulses and elevated AC voltage

Accelerated aging of 15 kV Cross-linked Polyethylene (XLPE) and Ethylene Propylene Rubber (EPR) power cables was carried out in the experiments set for the study of this thesis. The degradation of cable insulation under different aging conditions was studied and compared. The study helped to understand the effects of different factors on the aging of XLPE and EPR cable insulation. In the study, degradation of XLPE cable insulation caused by switching impulses was investigated. The deterioration of EPR cable insulation initiated by elevated ac voltage and switching impulses were also studied. Measurements of partial discharge parameters, capacitance, and dissipation factor were analyzed to evaluate the condition of cable insulation during accelerated aging process. Measurement of ac breakdown voltage provided evidence of the cables’ remaining dielectric strength after accelerated aging

The Multi-Stress Aging of 15 kV EPR Power Cables

This research is focused on the multi-stress aging phenomena and lifetime estimation of 15 kV EPR cable. In order to gain the suitable parameters for the lifetime estimation, the aging study on the EPR cable samples as well as on the cable layers’ dielectrics samples was carried out at the High Voltage Laboratory of Mississippi State University. During the multi-stress aging study of 15 kV EPR cable samples, the EPR cable samples underwent electrical stress, thermal stress, and environmental effects. The aging time for the EPR cables varied from 650 hrs to 1300 hrs. An empirical aging model describing the cables’ lifetime was derived from the partial discharge measurements results. The aging study on the EPR cable layers’ dielectrics was achieved as well. The EPR insulation material samples were aged by combined electrical and thermal stress, while the material samples of inner semi-conducting layer, outer semi-conducting layer, and outer low-density polyethylene (LDPE) jacket were aged by thermal stress. The measurement data was used for the newly proposed lifetime estimation method. A new lifetime estimation method was introduced for the EPR cables. The method assumed that the failures of cables results from the expansion of voids/cavities initiated from the defects in the EPR insulation layer. The proposed lifetime estimation method applied the finite element method (FEM) to solve the electric field distribution inside the EPR cable with the existence of voids/cavities. The parameters were derived from the aging study on the EPR insulation material samples. Assuming the voids/cavities would expand in the direction of the maximum electric field stress, the lifetime of the EPR cables was then estimated through the iteration. The introduced method helped to establish a relationship between the aging study of insulation material samples and the aging of EPR cable samples, which was long missing in the past studies. It also provided a new way to assess the reliability of the EPR cable

Graph-Skeleton: ~1% Nodes are Sufficient to Represent Billion-Scale Graph

Due to the ubiquity of graph data on the web, web graph mining has become a hot research spot. Nonetheless, the prevalence of large-scale web graphs in real applications poses significant challenges to storage, computational capacity and graph model design. Despite numerous studies to enhance the scalability of graph models, a noticeable gap remains between academic research and practical web graph mining applications. One major cause is that in most industrial scenarios, only a small part of nodes in a web graph are actually required to be analyzed, where we term these nodes as target nodes, while others as background nodes. In this paper, we argue that properly fetching and condensing the background nodes from massive web graph data might be a more economical shortcut to tackle the obstacles fundamentally. To this end, we make the first attempt to study the problem of massive background nodes compression for target nodes classification. Through extensive experiments, we reveal two critical roles played by the background nodes in target node classification: enhancing structural connectivity between target nodes, and feature correlation with target nodes. Followingthis, we propose a novel Graph-Skeleton1 model, which properly fetches the background nodes, and further condenses the semantic and topological information of background nodes within similar target-background local structures. Extensive experiments on various web graph datasets demonstrate the effectiveness and efficiency of the proposed method. In particular, for MAG240M dataset with 0.24 billion nodes, our generated skeleton graph achieves highly comparable performance while only containing 1.8% nodes of the original graph.Comment: 21 pages, 11 figures, In Proceedings of the ACM Web Conference 2024 (WWW'24

DEVELOPMENT OF A KIND OF FLAVORING TABLETS FOR CHILDREN'S USE

Objective: In this study, based on children's medication preferences, Synsepalum dulcificum and Siraitia grosvenorii as raw material were used to develop a flavoring medicine for children. Methods:  Synsepalum dulcificum and Siraitia grosvenorii as the raw material were applied to extract the Synsepalum dulcificum powder and Siraitia grosvenorii powder respectively, according to the orthogonal test design; the optimal proportion of flavoring powder was obtained. Low-substituted hydroxypropyl cellulose(L-HPC), polyvinylpolypyrrolidone(PVPP), sodium carboxymethyl starch(CMS-Na）, microcrystalline cellulose(MCC) were taken, according to the orthogonal test design the optimum proportion of auxiliary materials, then the flavoring tablets was prepared according to the preparation process. Results: Through orthogonal test design, the optimum ratio of Synsepalum dulcificum: Siraitia grosvenorii was 1:3, and mixing them up in proportion; the optimum ratio of L-HPC: PVPP: CMS-Na: MCC was 10: 8: 3: 6, and mix them up in proportion. Equal amounts of sugar and salt were obtained by mass ratio of 1 to 1. Mixing 1/3 amount of flavoring powder with 3/4 amount of auxiliary materials, using 20% ethanol as a wetting agent, using the remaining sugar as a filler, and granulating. After the granules were dried and whole grain, add the remaining auxiliary materials and magnesium stearate were added, then the flavoring tablets were prepared. Conclusion: The effects of this formula were prominent, which could effectively intervene the taste of children's medicine; solve the practical problems concerning taking medications in children. Keywords: Synsepalum dulcificum; Siraitia grosvenorii; drug use in children; flavoring tabletsÂ

Positive association between serum lactate dehydrogenase levels and blood pressure: evidence from NHANES 2015–2016

BackgroundSerum lactate dehydrogenase (sLDH) is an enzyme implicated in tissue injury and inflammatory responses. Despite its established role in these pathophysiological processes, the association between sLDH and blood pressure remains underexplored. The present findings suggest that sLDH could emerge as a valuable biomarker for blood pressure regulation and may hold significant promise in the management of hypertension.MethodsOur investigation utilized data from the National Health and Nutrition Examination Survey (NHANES) 2015–2016, comprising 3,469 participants after excluding those under the age of 20, individuals on antihypertensive therapies, and cases with incomplete data. sLDH levels were categorized into tertiles, while blood pressure measurements were conducted under standardized protocols. To elucidate the relationship between sLDH levels and blood pressure, multivariate regression analyses and smooth curve fitting techniques were employed, adjusting for 17 covariates, including age, sex, and body mass index.ResultssLDH corresponds with both systolic blood pressure (SBP) and diastolic blood pressure (DBP). The adjusted smooth curve fitting diagram demonstrates a linear positive connection between sLDH and SBP, with an increment of 0.053 mmHg (95% CI: 0.032, 0.074; p < 0.001) in SBP for every 1 U/L increment in LDH concentrations. The connection between sLDH and DBP is non-linear. sLDH concentrations below 123 U/L have a linear positive connection with DBP, increasing 0.079 mmHg (95% CI: 0.042, 0.115, p < 0.001). When sLDH concentrations exceed 123 U/L, there is not a substantial connection with DBP (P = 0.574).ConclusionOur study demonstrates a linear positive correlation between sLDH and SBP. A non-linear association was observed between sLDH and DBP, with a positive relationship for sLDH levels below 123 U/L. These findings underscore the potential of sLDH as a biomarker for blood pressure regulation

Efficacy and safety of Danggui Niantong Decoction in patients with gout: a systematic review and meta-analysis

Background: This study aims to evaluate the efficacy and safety of Danggui Niantong Decoction (DGNT) systematically on gout treating.Methods: This study was registered in PROSPERO, and the registration number was CRD42021271607. By the end of December, 2022, literature research was conducted among eight electronic databases. Main results of this study were blood uric acid (BUA) and Creactive protein (CRP). Secondary outcomes were erythrocyte sedimentation rate (ESR), serum creatinine (Scr), urinary protein quantified at 24 h (Upro), and interleukin-8 (IL-8). Study screening, data collection, as well as quality assessment were performed by two reviewers independently, and analysis was completed using Stata (SE15.0) and Review Manager (5.4).Results: A total number of 13 studies were included in our meta-analysis (n = 1,094 participants). Results showed DGNT combined with conventional western medicine (CWM) was more effective than WM alone in BUA (weighted mean differences (WMD) = −3.49, 95% confidence interval (CI) [−50.36, −32.59], p = 0.000), CRP (WMD = −41.48, 95% CI [−4.32, −2.66], p = 0.017), ESR (WMD = −6.23, 95% CI [−9.28, −3.17], p = 0.019), Scr (WMD = −18.64, 95% CI [−23.09, −14.19], p = 0.001), Upro (WMD = −0.72, 95% CI [−0.91, −0.53], p = 0.000), and IL-8 (WMD = −4.77, 95% CI [−11.48, 1.94], p = 0.000). None of the adverse effects noted were severe, and no life-threatening event was reported.Conclusion: This study shows that DGNT combined with CWM seems to have an effective clinical therapeutic potential. In addition, it also provides a scientific basis for better clinical application of DGNT in the future.Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021271607; Identifier: PROSPERO, CRD42021271607

A review on radiation-induced nucleation and growth of colloidal metallic nanoparticles

This review presents an introduction to the synthesis of metallic nanoparticles by radiation-induced method, especially gamma irradiation. This method offers some benefits over the conventional methods because it provides fully reduced and highly pure nanoparticles free from by-products or chemical reducing agents, and is capable of controlling the particle size and structure. The nucleation and growth mechanism of metallic nanoparticles are also discussed. The competition between nucleation and growth process in the formation of nanoparticles can determine the size of nanoparticles which is influenced by certain parameters such as the choice of solvents and stabilizer, the precursor to stabilizer ratio, pH during synthesis, and absorbed dose