Centrifuge model test on performance of thermosyphon cooled sandbags stabilizing warm oil pipeline buried in permafrost

The thaw settlement of pipeline foundation soils in response to the operation of the first China-Russia Crude Oil Pipeline along the eastern flank of the northern Da Xing'anling Mountains in Northeast China was simulated in a physical model test(with a similitude ratio of 1/73) in a geotechnical centrifuge. Two pipes of a supported and an unsupported section were evaluated over a testing period for simulating 20 years of actual pipeline operation with seasonal cyclically changing oil and ambient temperatures. The results show that pipe settlement of the supported pipe was 45% of settlement of the unsupported pipe. Settlement for the unsupported section was approximately 35% of the thaw bulb depth below the initial pipe elevation, only 30% of that for the supported pipe due to the influence of the supports. The final thaw bulbs extended approximately 3.6 and 1.6 times of the pipe diameter below the unsupported and supported pipe bottom elevations, respectively. The sandbag supports kept frozen during the test period because of cooling effect of the thermosyphons. The maximum bending stress induced over the 20 m span length from bearing of the full cover over the pipe would be equivalent to40% specified minimum yield strength(SMYS). Potential buckling of the pipe should be considered as the ground thaws.This study also offers important data for calibration and validation of numerical simulation models.

Study on Toxicity of 9 Biocontrol Microbial Products to Adult Population of Tobacco Beetle,Lasioderrma serricorne(Fabricius)

[Objectives]The paper was to study the toxicity of 9 biocontrol microbial products to adult population of Lasioderrma serricorne.[Methods]Nine biocontrol microbes were used as test materials to study their toxicity to the experimental population of L.serricorne adults.[Results]The toxicities of these biocontrol microbes from low to high at 5 d post spraying were:Luhai Beauveria bassiana powder(LC_(50)=462.752×10^(8) spores/L),Meichongzhi B.bassiana powder(LC_(50)=9713.157×10^(8) spores/L),Yiqiang Bio B.bassiana powder(LC_(50)=11203.321×10^(8)spores/L),Nongbao Bio B.bassiana powder(LC_(50)=12188.866×10^(8) spores/L),Yeshengwang B.bassiana powder(LC_(50)=21685.532×10^(8) spores/L);Fatu Bacillus thuringiensis suspension(LC_(50)=1.0844×10^(8) IU/L),Laojite B.thuringiensis suspension(LC_(50)=2.056×10^(8) IU/L),Lujinwa B.thuringiensis powder(LC_(50)=2.273×10^(8) IU/L),Nongbao Bio B.thuringiensis powder(LC_(50)=18.399×10^(8) spores/L).The toxicities of these biocontrol microbes from low to high at 10 d post spraying were:Nongbao Bio B.bassiana powder(LC_(50)=0.072×10^(8) spores/L),Yiqiang Bio B.bassiana powder(LC_(50)=2.484×10^(8) spores/L),Luhai B.bassiana powder(LC_(50)=44.551×10^(8) spores/L),Meichongzhi B.bassiana powder(LC_(50)=96.447×10^(8) spores/L),Yeshengwang B.bassiana powder(LC_(50)=723.347×10^(8) spores/L);Lujinwa B.thuringiensis powder(LC_(50)=0.0001×10^(8) IU/L),Fatu B.thuringiensis suspension(LC_(50)=0.045×10^(8) IU/L),Laojite B.thuringiensis suspension(LC_(50)=0.0644×10^(8) IU/L),Nongbao Bio B.thuringiensis powder(LC_(50)=1.899×10^(8) spores/L).The toxicities of these biocontrol microbes from low to high at 15 d post spraying were:Meichongzhi B.bassiana powder(LC_(50)=0.001×10^(8) spores/L),Nongbao Bio B.bassiana powder(LC_(50)=0.01×10^(8) spores/L),Yiqiang Bio B.bassiana powder(LC_(50)=0.084×10^(8) spores/L),Luhai B.bassiana powder(LC_(50)=2.370×10^(8) spores/L),Yeshengwang B.bassiana powder(LC_(50)=8.915×10^(8)spores/L);Lujinwa B.thuringiensis powder(LC_(50)=0.16×10^(4) IU/L),Laojite B.thuringiensis suspension(LC_(50)=0.185×10^(4) IU/L),Fatu B.thuringiensis suspension(LC_(50)=32.211×10^(4) IU/L),Nongbao Bio B.thuringiensis powder(LC_(50)=1590×10^(4) spores/L).[Conclusions]According to the three stages of tube rubbing,it is found that the control effects of Lujinwa B.thuringiensis powder and Meichongzhi B.bassiana powder are the best,and the results will provide technical support for the biological control of L.serricorne adults.

Occurrence Regularity and Life History of Cigarette Beetle Lasioderrma serricorne(Fabricius)in Tobacco Leaf Threshing and Redrying Workshop

[Objectives]The paper was to study the occurrence regularity and life history of cigarette beetle Lasioderrma serricorne(Fabricius)in tobacco leaf threshing and redrying workshop.[Methods]With the tobacco leaf threshing and redrying workshop as the survey site,the occurrence regularity of L.serricorne was investigated,and the life history table was inferred according to its biological characteristics.The temperature,humidity and duration of tobacco leaf threshing and redrying were simulated in the laboratory to study the survival rate of all states of L.serricorne in this environment.[Results]The lifecycle of L.serricorne in tobacco leaf threshing and redrying workshop was:the overwintering generation pupated in late February;the pupa began to emerge in early March,and reached its peak in late March.The first-generation eggs started hatching in late March,pupated in late May,emerged in early June,and reached the peak eclosion of the first-generation adults in mid-July.The second-generation eggs began to hatch in late July,pupated in mid-August,emerged in late August,and reached the peak eclosion of the second-generation adults in mid-September.The third-generation eggs began to hatch in mid-September;most of the larvae began to overwinter,some pupated in mid-November and survived the winter as pupae,and some pupae emerged to adults.The survival test results of different states of L.serricorne under simulated temperature,humidity and duration in the tobacco leaf threshing and redrying process showed that the mortality rates of eggs in simulated 1,2 and 3 conditions were about 51.22%,90.24% and 100%,and the mortalities of larvae in simulated 1,2 and 3 conditions were about 18.30%,81.25%and 100%,respectively.The mortalities of pupae in simulated 1,2 and 3 conditions were about 69.39%,100% and 100%,and the mortalities of adults in simulated 1,2 and 3 conditions were about 100%,100% and 100%,respectively.[Conclusions]L.serricorne of different states can be killed by appropriately raising the temperature during threshing and redrying.

GEE-Based monitoring method of key management nodes in cotton production

The high-temporal-resolution monitoring of key management nodes in cotton management via agricultural remote sensing is vital forfield cotton macro-statistics,particularly for predicting cotton production and obtaining comprehensive data.This study examines Shihezi,Xinjiang as a case study,utilizing Sentinel-1 and Sentinel-2 data from 2019 to 2021.Three machine learning models(RF,SVM,and CART)were employed to extract annual crop classification area rasters,monitor weekly cultivation progress,and monitor abandoned cropland during the cultivation period.The results demonstrate that the random forest model has produced satisfactory results in gridded extraction for cotton classification areas,achieving the producer’s accuracy of the cotton category reached 98.5%,and the kappa coefficient is 0.947.Cotton cultivated in 2021 began is a week later than in 2020,yet exhibited a faster cultivate speed.The proportion of abandoned cottonfields in the study area rose in 2020 compared to 2019.The methodology presented in this study has a certain reference value for exploring the monitoring of continuous changes in crops over the years and macro-monitoring of important activities in the entire growth cycle.

Droplets deposition and harvest-aid efficacy for UAV application in arid cotton areas in Xinjiang,China

With the development of Unmanned Aerial Vehicle(UAV)sprayers,the application of low-volume spraying of harvest-aid and other agrochemicals to cotton using UAVs is becoming a new agronomic trend worldwide.The effect of spray volume and canopy density for UAV spraying is significant but was rarely studied.In this study,five representative spray volumes were explored to examine the effect of spray volume on deposition and harvest-aid efficacy for cotton using a UAV sprayer.To explore the effect of canopy density,similar tests were carried out in a field located nearby with a lower leaf area index(LAI).A conventional trailer boom sprayer was selected for comparison.Different spray volumes had a significant effect on defoliation,but had no significant effect on boll opening and fiber quality.A higher defoliation rate was achieved in the lower LAI field.The total rate of defoliation using the UAV was inferior to the boom sprayer in the high LAI field for lower deposition and defoliation rate in the lower canopy.Considering the deposition,defoliation rate,and working efficiency,a spray volume of 15.0 L/hm^(2) with an average droplet size of 150μm is recommended for UAV application.