基于实际预压载作业的自升式平台环境载荷图谱绘制新思路

The environmental load chart is an important technical support required for the jack-up drilling platform to facilitate its adaptation to different operating waters and ensure the safety of operation.This chart is a crucial part of the platform operation manual.The chart data are closely related to external factors such as water depth,wind,wave,and current conditions of the working water,as well as to the structural characteristics of the platform itself and the number of variable loads.This study examines the platform state under extreme wind,wave,and current conditions during preloading.In addition,this study focuses on the difference between the ultimate reaction force of the pile leg during preloading and the reaction force of the pile leg without considering any environmental load before preloading.Furthermore,the relationship between the difference and the new reaction force of the pile leg caused by the combination of different environmental conditions is established to facilitate the construction of a new form of environmental load chart.The newly formed chart is flexible and simple;thus,it can be used to evaluate the environmental adaptability of the platform in the target well location and provides the preloading target demand or variable load limit according to the given environmental constraints.Moreover,the platform can perform personalized preloading operations,thereby improving its capability to cope with complex geological conditions,such as reducing punch-through risks.This condition reduces the load on jacking system devices and increases its service life.

Study on Extraction Process of Sipunculus nudus Polysaccharide and Its Antioxidant Activity

[Objectives] This study was conducted to optimize the extraction process of Sipunculus nudus polysaccharide. [Methods]S. nudus polysaccharide was extracted by ultrasonic water extraction,with the marine S. nudus as a raw material from Sanya City,Hainan Province,by single factor variable method,to find the optimal extraction conditions including ultrasonic power,solid-liquid ratio,ultrasonic extraction temperature,ultrasonic extraction time,ultrasonic extraction times and lye concentration. The absorbance of the polysaccharide was determined by an ultraviolet spectrophotometer,and polysaccharide yield were calculated. The antioxidant activity of scavenging hydroxyl and DPPH radicals was measured at different concentrations. [Results]The optimal extraction conditions for S. nudus polysaccharide were as follows： solid-liquid ratio at 1∶11 mg/ml,extraction temperature at 60 ℃,three times of ultrasonic extraction,ultrasonic power of 960 W,extraction time of 1. 5 h,and lye concentration of 5%,under which the polysaccharide yield was 3. 21%. The scavenging rates of hydroxyl radical and DPPH radical were 12. 58% at the concentration of 0. 20 mg/ml. Moreover,the scavenging rates increased significantly with the increase of concentration. [Conclusions] This method is a new trial with satisfactory results.

Symptoms associated with nucleic acid turning-negative-time in COVID-19 patients?

Objective:To explore on the association between nucleic acid turning-negative-time and traditional Chinese medicine(TCM)symptoms in coronavirus disease 2019(COVID-19)patients with the Omicron variant.Method:For this retrospective cross-sectional study,we enrolled 189 patients with COVID-19(age 20-90 years)were included.multiple linear regression models were used to investigate the TCM symptoms affecting the nucleic acid turning-negative-time of COVID-19 patients,during the process of data analysis,taking with nucleic acid turning-negative-time as the dependent variable,and TCM symptoms as independent variables,and at the same time,sex,age,hypertension,diabetes,and coronary heart disease were as confounding variables.Results:The study found that the most common TCM symptoms of COVID-19 patients with Omicron were cough,dry throat,expectoration,fever,sore throat,pharyngeal itching,running nose,and nasal congestion.Regression analysis showed that the fit regressive equation showed a significant difference(F=4.286,P<0.001),R=0.400,the adjusted R^(2)=0.123,and three variables in the regression equation showed significant difference(P<0.05).The results showed that nucleic acid turningnegative-time was mostly related to constipation,fever,and expectoration.If the patients had the symptoms of constipation,fever,and expectoration;that is,if patients showed these symptoms,the turning-negative-time of nucleic acid in patients with Omicron will be prolonged.Conclusions:Treatment based on symptoms for patients with constipation,fever,and expectoration may have important clinical significance for the COVID-19 patients with Omicron.

Diffusion Analysis and Modeling of Potassium Sorbate in Gelatin Based Antimicrobial Film

The diffusion of potassium sorbate incorporated into gelatin based antimicrobial film was measured. Fick’s second law was applied to investigate the mechanism of potassium sorbate released from the films. The mathematical model was established. The result showed that the diffusion coefficient D increased with the increase of potassium sorbate concentration. The effects of temperature 5?C, 25?C and 35?C on diffusion were investigated. The mechanisms of potassium sorbate diffusion through gelatin films were mainly Fickian and determined by the power law model Mt/M∞ = k × tn. A decrease in temperature from 35?C to 5?C resulted in a reduction of diffusion coefficients from 5.20 × 10?12 to 1.36 × 10?12 m2/s. The diffusion coefficient of potassium sorbate is influenced by receiving solution pH values.

DEM investigation on conveying of non-spherical particles in a screw conveyor

Screw conveyors are extensively used in modern industry such as metallurgy,architecture and pharmaceutical due to their high-efficiency in the transportation of granular materials.And substantial efforts have been devoted to the study of the screw conveyors.Numerical method is an effective way to study screw conveyor.However,previous studies have mainly focused in the regime of spherical particles while the in-depth investigations for non-spherical particles that should be the most encountered in practical applications are still limited.In view of the above situations,discrete element method(DEM),which has been widely accepted in simulating the discrete systems,is utilized to investigate the conveying process of non-spherical particles in a horizontal screw conveyor,with particles being modeled by super-ellipsoids.In addition,a wear model called SIEM(Shear Impact Energy Model)is incorporated into DEM to predict the wear of screw conveyor.The DEM simulation results demonstrate that the particle shape is influential for the flow behaviors of particles and the wear of conveyor.The conveying performance evaluated quantitatively of both mass flow rate and power consumption is subsequently obtained to investigate the effect of sphericity of particle with different operation parameters.Moreover,particle collision frequency and collision energy consumption are acquired to investigate the possible particle breakage between particles and screw blade.The comparisons between particle-particle collision and particle-wall collision reveal that particles with large shape index have more possibility to be damaged in particle-wall impingement.