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Large-Scale Model of a Landslide with Flexible Anti-Slide Piles

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Journal of Earth Science 2020年

作者： Chang Zhou Xinli Hu dwayne d.tannant Chu Xu Qiang Wang Faculty of Engineering China University of Geosciences School of Engineering University of British Columbia

A large-scale physical model was constructed to study the effect that flexible, anti-slide piles would have on the Majiagou landslide, and how their performance would compare with the no pile or rigid pile cases. A large-scale physical model was constructed to study the behavior of the Majiagou landslide. The landslide model contained six 0.57 m long piles made of polyurethane. A load was applied in a stepwise increasing manner to the rear of the landslide model to simulate a thrust force. Instrumentation included soil pressure cells, strain gauges, a 3d laser scanner, and digital photography. The bending moment in the pile exhibits a triangular distribution, peaking at the base of the sliding zone. The pile initially moved in unison with the landslide deformations. The coordinated deformation of the pile and the landslide created a more uniform distribution of soil pressures in the landslide compared to another model that used rigid piles. The modeling results suggest that landslides stabilized with flexible piles can sustain higher thrust loads and larger landslide displacements before shear surfaces develop through the landslide. Thus, our results suggest that a landslide stabilized with flexible piles would fail less catastrophically than would an otherwise identical one stabilized with rigid piles.

关键词： Landslide physical model test flexible anti-slide piles pile stiffness

Soybean Response to Weed Residues in the Soil

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Agricultural Sciences 2024年第8期15卷 801-811页

作者： dwayne d. Joseph Michael W. Marshall Matthew Cutulle department of Plant and Environmental Sciences Clemson University Clemson SC USA Edisto Research and Education Center Clemson University Blackville SC USA Coastal Research and Education Center Clemson University Charleson SC USA

Soybean production systems that return plant residues to the soil surface are gaining in popularity. As these practices become more widespread, more crop and weed residues are being introduced into the upper soil profile. Greenhouse studies were conducted to determine the effects of varying concentrations of Palmer amaranth and pitted morningglory plant residues (aboveground portion of the plant) on soybean production. The study was arranged in a completely randomized experimental design with five treatments and five replications. Palmer amaranth and pitted morningglory residues were incorporated into soil at 20,000, 40,000, 80,000 and 160,000 ppm. Inert plastic residue at the same residue levels was included as a check. Soybean dry weight, leaf area and leaf tissue nutrient content were recorded during the study. A decrease in soybean dry weight and leaf area was observed as Palmer amaranth residue in the soil increased. Palmer amaranth residues of 160,000 ppm and 80,000 ppm in the soil significantly reduced soybean dry weight by 69% and 59%, respectively, and soybean leaf area by 60% and 57%, respectively. In contrast, pitted morningglory and inert plastic residues had no observable effect on soybean growth and development. This study demonstrated Palmer amaranth residues in the soil impacted early season soybean growth and development.

关键词： Reduced Tillage Plant Residues Allelopathy Glycine max L.

Centrifuge and numerical modeling of h-type anti-slide pile reinforced soil-rock mixture slope

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Journal of Mountain Science 2023年第5期20卷 1441-1457页

作者： ZHANG Hao XING Hao-feng XUE dao-rui tannant dwayne department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China School of Urban Construction and Transportation Hefei UniversityHefei 230601China School of Engineering University of British ColumbiaKelowna BC V1V 1V7Canada Guangdong Communication Planning and design Institute Group Co. Ltd.Guangzhou 510507China

due to the loose structure,high porosity and high permeability of soil-rock mixture slope,the slope is unstable and may cause huge economic losses and *** h-type anti-slide pile is regarded as an effective means to prevent the instability of soilrock mixture *** this paper,a centrifuge model test was conducted to investigate the stress distribution of the h-type anti-slide pile and the evolution process of soil arching during the loading.A numerical simulation model was built based on the similar relationship between the centrifuge model and the prototype to investigate the influence factors of the pile spacing,anchored depth,and crossbeam stiffness,and some recommendations were proposed for its *** results show that the bending moment distribution of the rear pile exhibits Wshaped,while for the front pile,its distribution resembles *** soil arching evolution process during loading is gradually dissipated from bottom to top and from far to *** the loading,the change of bending moment can be divided into three stages,namely,the stabilization stage,the slow growth stage,and the rapid growth *** engineering projects,the recommended values of the pile spacing,anchored depth,and crossbeam stiffness are 4.0d,2.0d,and 2.0EI,where d and EI are the diameter and bending stiffness of the h-type anti-slide pile respectively.

关键词： Centrifugemodel test Numerical simulation h-type anti-slide pile Soil-rock mixture slop Soil arching

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深凹露天转地下开采高陡边坡变形与破坏规律

北京科技大学学报 2010年第2期32卷 145-151页

作者：宋卫东杜建华杨幸才 dwayne d.tannant 北京科技大学土木与环境工程学院北京100083 加拿大不列颠哥伦比亚大学(奥克那根分校)工程学院

以大冶铁矿为工程背景,采用相似材料模型实验和数值模拟计算相结合的方法,对深凹露天转地下开采高陡边坡的变形和破坏规律进行了系统研究.首先,模型相似实验中,采用百分表、压力传感器和近景摄影测量等手段监测模型的应力应变和破坏特征... 详细信息

以大冶铁矿为工程背景,采用相似材料模型实验和数值模拟计算相结合的方法,对深凹露天转地下开采高陡边坡的变形和破坏规律进行了系统研究.首先,模型相似实验中,采用百分表、压力传感器和近景摄影测量等手段监测模型的应力应变和破坏特征,对围岩位移和破坏裂纹进行系统分析,揭示了高陡边坡的变形和破坏基本规律.其次,采用有限差分软件,从地表沉降量、应力值变化和塑性区分布等方面与相似材料实验结果进行了对比分析.结果表明,高边坡竖向最大沉降为28.2mm,围岩破坏程度随着开采深度的增加递增,塑性区范围不断扩大,剪切破坏主要集中在两侧边坡的边脚部位.相似模型实验和数值模拟相结合可以较好地揭示深凹露天转地下开采过程中高陡边坡的变形和破坏基本特征,是一种较好的理论研究方法.

关键词：地下开采露天矿高陡边坡变形与破坏模型实验

In vitro and in vivo application of RNA interference for targeting genes involved in peritrophic matrix synthesis in a lepidopteran system

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Insect Science 2013年第1期20卷 92-100页

作者： Umut Toprak doug Baldwin Martin Erlandson Cedric Gillott Stephanie Harris dwayne d. Hegedus Agriculture and Agri-Food Canada Ottawa Ontario Canada department of Biology University of Saskatchewan Canada department of Plant Protection Faculty of Agriculture University of Ankara Turkey department of Food and Bioproduct Sciences University of Saskatchewan Saskatoon SK Canada

The midgut of most insects is lined with a semipermeable acellular tube, the peritrophic matrix （PM）, composed of chitin and proteins. Although various genes encoding PM proteins have been characterized, our understanding of their roles in PM structure and function is very limited. One promising approach for obtaining functional information is RNA interference, which has been used to reduce the levels of specific mRNAs using double-stranded RNAs administered to larvae by either injection or feeding. Although this method is well documented in dipterans and coleopterans, reports of its success in lepidopterans are varied. In the current study, the silencing midgut genes encoding PM proteins （insect intestinal mucin 1, insect intestinal mucin 4, PM protein 1） and the chitin biosynthetic or modifying enzymes （chitin synthase-B and chitin deacetylase 1） in a noctuid lepidopteran, Mamestra configurata, was examined in vitro and in vivo. In vitro studies in primary midgut epithelial cell preparations revealed an acute and rapid silencing （by 24 h） for the gene encoding chitin deacetylase 1 and a slower rate of silencing （by 72 h） for the gene encoding PM protein 1. Genes encoding insect intestinal mucins were slightly silenced by 72 h, whereas no silencing was detected for the gene encoding chitin synthase-B. In vivo experiments focused on chitin deacetylase 1, as the gene was silenced to the greatest extent in vitro. Continuous feeding of neonates and fourth instar larvae with double-stranded RNA resulted in silencing of chitin deacetylase 1 by 24 and 36 h, respectively. Feeding a single dose to neonates also resulted in silencing by 24 h. The current study demonstrates that genes encoding PM proteins can be silenced and outlines conditions for RNA interference by per os feeding in lepidopterans.

关键词： chitin deacetylase chitin synthase-B lepidoptera peritrophic matrix,peritrophin RNA interference

Proteomics analysis of Trichoplusia ni midgut epithelial cell brush border membrane vesicles

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Insect Science 2019年第3期26卷 424-440页

作者： Muhammad Afzal Javed Cathy Coutu david A. Theilmann Martin A. Erlandson dwayne d. Hegedus Saskatoon Research and development Centre Agriculture and Agri-Food Canada Saskatoon Saskatchewan Canada Summerland Research and development Centre Agriculture and Agri-Food Canada Summerland British Columbia Canada department of Food & Bio-Product Sciences University of Saskatchewan Saskatoon Saskatchewan Canada

The insect midgut epithelium is composed of columnar, goblet, and regenerative cells. Columnar epithelial cells are the most abundant and have membrane protrusions that form the brush border membrane (BBM) on their apical side. These increase surface area available for the transport of nutrients, but also provide opportunities for interaction with xenobiotics such as pathogens, toxins and host plant allelochemicals. Recent improvements in proteomic and bioinfbrmatics tools provided an opportunity to determine the proteome of the T. ni BBM in unprecedented detail. This study reports the identification of proteins from BBM vesicles (BBMVs) using single dimension polyacrylamide gel elec? trophoresis coupled with multi-dimensional protein identification technology. More than 3000 proteins were associated with the BBMV of which 697 were predicted to possess either a signal peptide, at least one transmembrane domain or a GPI-anchor signal. Of these, bioinfbrmatics analysis and manual curation predicted that 185 may be associated with the BBMV or epithelial cell plasma membrane. These are discussed with respect to their predicted functions, namely digestion, nutrient uptake, cell signaling, development, cell-cell interactions, and other functions. We believe this to be the most detailed proteomic analysis of the lepidopteran midgut epithelium membrane to date, which will provide information to better understand the biochemical, physiological and pathological processes taking place in the larval midgut.

关键词： brush border membrane vesicles midgut proteomic analysis Trichoplusiani

基于连续-非连续方法的裂隙破坏与相互作用研究

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工程地质学报 2019年第5期27卷 933-945页

作者：赵海军 dwayne tannant 郭捷冯雪磊马凤山中国科学院地质与地球物理研究所中国科学院页岩气与地质工程重点实验室北京100029 中国科学院地球科学研究院北京100029 不列颠哥伦比亚大学加拿大V1V1V7 中国科学院大学地球与行星科学学院北京100049

岩体内裂隙等非连续结构面对岩体的强度及变形等力学特性有着显著的影响,研究岩体裂隙起裂、扩展、相互作用和贯通机制,对工程岩体力学行为的表征和工程性能的评价十分重要。本文基于连续介质力学模型的离散元方法,通过考虑裂隙分布、... 详细信息

岩体内裂隙等非连续结构面对岩体的强度及变形等力学特性有着显著的影响,研究岩体裂隙起裂、扩展、相互作用和贯通机制,对工程岩体力学行为的表征和工程性能的评价十分重要。本文基于连续介质力学模型的离散元方法,通过考虑裂隙分布、模型加载条件及其与裂隙产状的关系,建立了一系列裂隙力学计算模型,研究了不同模型裂隙扩展演化特征和岩体破裂机制,分析了岩体裂隙扩展规律及其对岩体破坏路径和强度的影响,研究结果表明:(1)裂隙岩体模型加载条件下的破坏起裂点、最终贯通破坏特征及损伤分布受控于裂隙的产状及其与最大主压应力取向角度大小及围压大小。(2)裂隙弱面走向与最大主压应力取向斜交时,裂隙弱面在加载条件下其端部裂隙扩展、贯通破坏表现比较明显,反之,当裂隙弱面走向与最大主压应力取向一致时,裂隙弱面被动影响裂隙模型内新生裂隙的萌生、扩展和贯通模式,自身未出现新的扩展破坏。(3)裂隙数目的增多和围压的增大会显著增加模型内部剪切裂缝的数量和模型破坏后的破碎程度,模型内部的损伤区域主要围绕破裂面呈滑移线型交叉分布,非破裂面区域损伤呈条带状X型分布。(4)裂隙弱面走向与最大主压应力取向斜交时,裂隙对岩体模型强度的弱化程度高于裂隙弱面走向与最大主压应力取向一致的情况,而裂隙模型破坏后的残余强度则正好相反。

关键词：裂隙岩体连续-非连续裂隙形状裂隙起裂裂隙扩展损伤断裂

Identification of the Mamestra configurata （Lepidoptera Noctuidae） peritrophic matrix proteins and enzymes involved in peritrophic matrix chitin metabolism

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Insect Science 2016年第5期23卷 656-674页

作者： Umut Toprak Martin Erlandson doug Baldwin Steve Karcz Lianglu Wan Cathy Coutu Cedric Gillott dwayne d. Hegedus Agriculture and Agri-Food Canada Saskatoon SK Canada department of Biology University of Saskatchewan Saskatoon SK Canada department of Plant Protection Faculty of Agriculture University of Ankara Ankara Turkey department of Food and Bioproduct Sciences University of Saskatchewan Saskatoon SK Canada plant Biotechnology Institute National Research Council of Canada Saskatoon SK Canada

The peritrophic matrix （PM） is essential for insect digestive system physiol- ogy as it protects the midgut epithelium from damage by food particles, pathogens, and toxins. The PM is also an attractive target for development of new pest control strategies due to its per os accessibility. To understand how the PM performs these functions, the molecular architecture of the PM was examined using genomic and proteomic approaches in Mamestra configurata （Lepidoptera： Noctuidae）, a major pest of cruciferous oilseed crops in North America. Liquid chromatography-tandem mass spectrometry analyses of the PM identified 82 proteins classified as：（i） peritrophins, including a new class with a CBdIII domain; （ii） enzymes involved in chitin modification （chitin deacetylases）, di- gestion （serine proteases, aminopeptidases, carboxypeptidases, lipases and ^-amylase） or other reactions （/^-l,3-glucanase, alkaline phosphatase, dsRNase, astacin, pantetheinase）; （iii） a heterogenous group consisting of polycalin, REPATs, serpin, C-Type lectin and Lsti99/Lsti201 and 3 novel proteins without known orthologs. The genes encoding PM proteins were expressed predominantly in the midgut, cdNAs encoding chitin synthase-2 （McCHS-2）, chitinase （McCHI）, and fl-N-acetylglucosaminidase （McNAG） enzymes, in- volved in PM chitin metabolism, were also identified. McCHS-2 expression was specific to the midgut indicating that it is responsible for chitin synthesis in the PM, the only chitinous material in the midgut. In contrast, the genes encoding the chitinolytic enzymes were expressed in multiple tissues. McCHS-2, McCHI, and McNAG were expressed in the midgut of feeding larvae, and NAG activity was present in the PM. This information was used to generate an updated model of the lepidopteran PM architecture.

关键词： chitin Mamestra configurata peritrophic matrix protein

Evaluation of 2,4-d-Choline Based Herbicide Systems in 2,4-d Tolerant Soybean (<i>Glycine max</i>L.)

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Agricultural Sciences 2017年第5期8卷 385-396页

作者： dwayne d. Joseph Colton H. Sanders Michael W. Marshall department of Plant and Environmental Sciences Clemson University Clemson SC USA Edisto Research and Education Center Clemson University Blackville SC USA

Weeds are the most limiting factor in soybean production in South Carolina. With early emergence and rapid growth, weeds effectlively compete for water, nutrients, and light resources. The recent evolution of herbicide resistant weeds has made it increasingly difficult for growers to effectively control weeds in soybean. Glyphosate and ALS-resistant Palmer amaranth biotypes have spread rapidly throughout South Carolina, especially in areas where resistance management is lacking. Soybean varieties have been recently developed with tolerance to 2,4-d. Field experiments were conducted at the Clemson University Edisto Research and Education Center located near Blackville, SC in 2012 and 2013 to evaluate selected 2,4-d choline based herbicide programs for weed management in 2,4-d tolerant soybean. Overall, all herbicide treatments were effective in controlling weeds at the POST2 timing. Palmer amaranth control was excellent;however, pitted morningglory was the most difficult. The 2,4-d plus glyphosate pre-mixture provided excellent control for all three weed species with >95% control at POST2 timing. In these treatments, the rate of 2,4-d choline plus glyphosate (1.09 kg ae ha-1 or 1.64 kg ae ha-1) did not have a significant effect on weed control (P = 0.3772). There was a decrease in pitted morningglory control 3 WAP in 2012 vs 2013 in plots treated with S-metolachlor + fomesafen because of a lack of activating soil moisture in 2012. Results from this study showed that all treatments evaluated provided good to excellent control of all 3 weed species. Based on the herbicide programs evaluated in the study, herbicide resistant weeds, such as Palmer amaranth, can be effectively controlled when treated at the correct growth stage.

关键词： Glyphosate Resistance 2 4-d Choline Weeds Soybean