A Review of the Methods of Identifying and Testing Plant Cold Resistance

Low-temperature stress is a major abiotic stress influencing plant growth,economic yield and quality worldwide. Precise and reliable identification and test of plant cold resistance is a foundation for exploring low-temperature damages,cold resistance mechanism of plants,cultivating and innovating quality cold-resistant germplasm resources,which is rather important for woody plants because their perennial and large-sized characteristics. Generally,most researches on plant cold-resistant physiology focused on identification and utilization of cold resistance worldwide,and a few on test methods of cold resistance,but cold resistance mechanism has been less reported. Therefore,researches on methods of identifying and testing plant resistance have achieved considerable progress,accumulated much experience and formed characteristics gradually in terms of methodology. Current methods of identifying plant cold resistance include open field / outdoor cultivation evaluation,cold and frost damage investigation,simulated cold weather,and mathematical model forecast. And the methods of testing plant cold resistance include growth condition test,frozen index investigation,electrolyte leakage,bioelectrical impedance mapping and so on. Synthesizing the methods of identifying and testing plant cold resistance should be a key matter in the present and future researches and application of plant cold resistance physiology,improvement and innovation of the identification and test will be an important direction of the future researches. Identification and test of plant cold resistance based on genomics,metabonomics and proteomics should be the new trend of the researches on physiology and ecology of plant cold resistance.

Obtaining 2D Soil Resistance Profiles from the Integration of Electrical Resistivity Data and Standard Penetration Test (SPT) and Light Dynamic Penetrometer (DPL) Resistance Tests—Applications in Mass Movements Studies

In Brazil and various regions globally, the initiation of landslides is frequently associated with rainfall;yet the spatial arrangement of geological structures and stratification considerably influences landslide occurrences. The multifaceted nature of these influences makes the surveillance of mass movements a highly intricate task, requiring an understanding of numerous interdependent variables. Recent years have seen an emergence in scholarly research aimed at integrating geophysical and geotechnical methodologies. The conjoint examination of geophysical and geotechnical data offers an enhanced perspective into subsurface structures. Within this work, a methodology is proposed for the synchronous analysis of electrical resistivity geophysical data and geotechnical data, specifically those extracted from the Light Dynamic Penetrometer (DPL) and Standard Penetration Test (SPT). This study involved a linear fitting process to correlate resistivity with N10/SPT N-values from DPL/SPT soundings, culminating in a 2D profile of N10/SPT N-values predicated on electrical profiles. The findings of this research furnish invaluable insights into slope stability by allowing for a two-dimensional representation of penetration resistance properties. Through the synthesis of geophysical and geotechnical data, this project aims to augment the comprehension of subsurface conditions, with potential implications for refining landslide risk evaluations. This endeavor offers insight into the formulation of more effective and precise slope management protocols and disaster prevention strategies.

Research of Test Method on Abrasion Resistance at Elevated Temperatures of Refractories

In this work,the factors and parameters of a test method on abrasion resistance at elevated temperatures were discussed and researched.First of all,the precision tests of the test method on abrasion resistance at elevated temperatures were conducted in 8 laboratories.The results such as the standard deviation and reproducibility show good repeatability and reliability.The relationship between the stability of refractory performance and the standard deviation of their wear value was analyzed.Then the impact of the heat treatment condition of unshaped refractories and oxidation of SiC sand as abrasive on the lost volume of the tested specimens was researched.

A New Test Method for Hot Abrasion Resistance on Refractories

Test methods for hot abrasion resistance of refractories in China and overseas were briefly introduced.A new test method for hot abrasion resistance was researched.The new method inherits test principle of cold abrasion resistance in Chinese standard totally,adopts compressed air pre-heating and electricity heating samples,and is featured with complete structure,good controllability,simple operation,and small size.The characteristics and operating procedure of HAT-14A tester were introduced.The hot abrasion resistance of various refractories at different temperatures was tested.

Numerical Simulation on the Resistance Performance of Ice-Going Container Ship Under Brash Ice Conditions

Ice resistance prediction is a critical issue in the preliminary design of ships navigating brash ice conditions, which is closely related to the safety of a ship to navigate encounter brash ice, and has significant effects on the kinds of propellers and motor power needed. In research on this topic, model tests and full-scale tests on ships have thus far been the primary approaches. In recent years, the application of the finite element method(FEM) has also attracted interest. Some researchers have conducted numerical simulations on ship–ice interactions using the fluid–structure interaction(FSI) method. This study used this method to predict and analyze the resistance of an ice-going ship, and compared the results with those of model ship tests conducted in a towing tank with synthetic ice to discuss the feasibility of the FEM. A numerical simulation and experimental methods were used to predict the brash ice resistance of an ice-going container ship model in a condition with three concentrations of brash ice(60%, 80%, and 90%). A comparison of the results yielded satisfactory agreement between the numerical simulation and the experiments in terms of both observed phenomena and resistance values, indicating that the proposed numerical simulation has significant potential for use in related studies in the future.

Discrete element modelling of railway ballast performance considering particle shape and rolling resistance

To simulate ballast performance accurately and efficiently,the input in discrete element models should be carefully selected,including the contact model and applied particle shape.To study the effects of the contact model and applied particle shape on the ballast performance(shear strength and deformation),the direct shear test(DST)model and the large-scale process simulation test(LPST)model were developed on the basis of two types of contact models,namely the rolling resistance linear(RRL)model and the linear contact(LC)model.Particle shapes are differentiated by clumps.A clump is a sphere assembly for one ballast particle.The results show that compared with the typical LC model,the RRL method is more efficient and realistic to predict shear strength results of ballast assemblies in DSTs.In addition,the RRL contact model can also provide accurate vertical and lateral ballast deformation under the cyclic loading in LPSTs.

Discussion on pile axial load test methods and their applicability in cold regions

The measurement of pile axial load is of great significance to determining pile foundation design parameters such as skin friction and end bearing capacity and analyzing load transfer mechanisms.Affected by the temperature and ice content of frozen ground,the interface contact relationship between pile foundation and frozen soil is complicated,making pile axial load measurements more uncertain than that in non-frozen ground.Therefore,it is necessary to gain an in-depth understanding of the current pile axial load test methods.Four methods are systematically reviewed:vibrating wire sensors,strain gauges,sliding micrometers,and optical fiber strain sensors.At the same time,the applicability of the four test methods in frozen soil regions is discussed in detail.The first two methods are mature and commonly used.The sliding micrometer is only suitable for short-term measurement.While the Fiber Bragg grating(FBG)strain gauge meets the monitoring requirements,the Brillouin optical time-domain reflectometer(BOTDR)needs further verification.This paper aims to provide a technical reference for selecting and applying different methods in the pile axial load test for the stability study and bearing capacity assessment of pile foundations in cold regions.

Nondestructive testing and assessment of consolidation effects of earthen sites

Earthen sites are widely distributed throughout China,and most of them belong to archaeological sites with significant values,which not only directly witness the origin,formation and development of Chinese civilization,but also possess important values for conservation and exhibition.Many researches and practices on their conservation and consolidation have been carried out:however,the consolidation effect is mainly judged by visual observation and expert evaluation.Scientific assessment of conservation and consolidation effects is a challenging issue.Many instruments in other fields cannot be directly applied to the conservation of cultural relics due to their peculiarity.In order to assess the effects of field conservation experiments,this paper tries to understand the consolidation effects at Liangzhu site using nondestructive or micro-damage methods,including thermo-physical parameters testing,infrared thermal imaging,high-density microelectrode resistivity testing,portable microscope observation,and hydrophilic and hydrophobic testing,and thereby explores the practicable methods for evaluating the properties of consolidation materials for earthen sites treatment.

考虑约束作用的混凝土柱耐火试验加载方式研究

为找到一种在构件耐火试验中能有效考虑整体结构对受火构件约束作用的加载方式,建立了2层2跨的钢筋混凝土框架和受火单柱的有限元模型,对比分析荷载比为0.2、0.4和0.6时,恒载、变位移加载、变力加载和交互加载方式下受火单柱与整体结构的内力、变形和耐火极限的差异。研究结果表明:恒载单柱不能准确反映整体结构受火柱的变形、轴力和耐火极限;变位移加载和变力加载在荷载比为0.2时能较好考虑整体结构中的约束作用,在荷载比为0.4和0.6时误差增大也不能准确反映整体结构的抗火性能;交互加载的相对误差随荷载比增大而增大,且最大误差小于20%。恒载、变位移加载、变力加载和交互加载中,交互加载可以较好考虑整体结构中的约束作用,近似达到整体结构试验的效果。

不同葡萄砧木抗寒抗抽干能力比较研究

[目的]气候变化新形势下,进一步筛选适宜西北地区抗寒、抗抽干葡萄砧木品种,可为葡萄免埋土栽培推广提供理论依据和技术支撑。[方法]本文以41Bmgt、Riparia、420Bmgt、101-14、196-17、44-53ma、110R、Rupestris du Lot、SO4、161-490、1103P、5BB、3309、Leon Millt共14种13年生葡萄砧木为试材,通过测定离体一年生枝条累计失水速率,结合田间调查葡萄砧木存活率和离体一年生枝条抽干率,以此来评价不同葡萄砧木品种抗抽干能力;结合前人研究及砧木品种特性,采用高低温交变试验箱模拟低温的方法,设置4(对照)、-15、-20、-25和-30℃一系列温度梯度水平,测定不同葡萄砧木一年生枝条相对电导率、丙二醛、游离脯氨酸、可溶性糖及可溶性蛋白5个生理生化指标,利用隶属函数法进行综合评价不同葡萄砧木的抗寒性。[结果]不同葡萄砧木的抗抽干能力由强到弱依次为:3309>161-490>196-17>Leon Millt>420Bmgt>44-53ma>Riparia>110R>1103P>SO4>101-14>41Bmgt>5BB>Rupestris du Lot;随着处理温度的降低,不同葡萄砧木枝条的抗寒指标总体呈现上升趋势,但不同品种之间存在差异。根据隶属函数的综合分析,结果显示各葡萄砧木的抗寒性由强到弱依次为:SO4>196-17>Leon Millt>5BB>Riparia>44-53ma>420Bmgt>1103P>3309>110R>Rupestris du Lot>101-14>41Bmgt>161-490。[结论]Riparia、196-17、44-53ma和Leon Millt具有较强的抗抽干能力和抗寒性,可作为我国西北地区免埋土葡萄砧木使用。

水下方向控制阀质量测试方法的设计

以API STD 17F—2017标准规定的水下方向控制阀(DCV)测试项目为基础,制定了具有可操作性的DCV质量测试方法。测试项目包括外压、内压、内泄漏、功能和连续性、污染流体循环、寿命、环境筛选和绝缘电阻测试,针对每一个测试项目给出了详细的测试目的、标准要求和测试步骤。本文方法通过了挪威船级社审核,并成功应用于渤海油气田浅水水下方向控制阀工程化产品的挪威船级社认证。

抗滑挡墙加固小型滑坡墙背推力研究

以西南山区某小型村寨滑坡为对象,采用数值模拟方法,研究抗滑挡墙墙背滑坡推力的分布形式,并引入正交试验,采用极差分析法探讨多物理参数对滑坡推力的影响。结果表明:抗滑挡墙墙背滑坡推力的分布曲线为“鼓肚形”,在靠近坡面一定范围内滑坡推力趋于零;滑带黏聚力、内摩擦角的折减系数及抗滑挡墙埋深对滑坡推力的影响较大;抗滑挡墙埋深对作用点高度的影响较大;滑坡推力作用点介于挡墙底部向上垂直高度20%~29%的位置,与刚体极限平衡法中的假设存在偏差。

环氧砂浆的三种非过流面耐磨性测试方法适用性分析

阐述了现有的非过流面耐磨性测试方法对环氧砂浆不适用的原因。通过调整三种测试方法的参数,绘制相应的磨损量-磨损时间(转数)曲线图,结合机械磨损理论的磨损过程图,分析三种非过流面耐磨性测试方法对环氧砂浆的适用性。最后,对三种非过流面耐磨性测试方法做出调整并进行适用性评价。

电炉冶炼复杂物料高温电阻测量方法的研究

电炉作为清洁能源装备,用于工业固废冶炼处理,实现复杂物料高附加值利用。然而工业固废物料成分较为复杂,物料在高温冶炼过程中涉及化学反应、温度场、电场、磁场等相互耦合作用,电阻等基本物理参数极其复杂、不稳定。以钛渣电炉为研究对象,研究电炉冶炼钛渣高温电阻测量方法,动态监测电炉实际冶炼过程中高温炉渣在不同冶炼阶段、不同工况情况下的电流、电压,通过对测量数据进行统计分析和理论计算,分析计算出高温钛渣在不同冶炼阶段、不同工况下的热态阻值,从而归纳总结出电炉冶炼反应合理用电参数,为电炉供电制度优化、电气参数设计提供基础数据理论支撑。

自然条件下建筑外墙涂料耐沾污性能的探究

随着人们生活水平的提高和建筑行业的发展,外墙涂料耐沾污性能已经成为一项重要的指标。本研究将外墙涂料试板放置于自然条件下,对其表面反射率进行持续测定,统计分析自然条件和使用标准灰的人工耐沾污试验结果。结果表明,外墙涂料试板在室外放置过程中,表面污染程度不断加大,反射率下降百分比不断上升,7个月后最高达17%。自然条件与人工耐沾污试验测定的结果存在一定差异,这表明相关标准还有待进一步完善以贴合现实情况。最后提出外墙涂料耐沾污测试方法可能的改进思路,为耐沾污外墙涂料产品发展和相关标准修订提供参考。

浅谈汽车地毯防霉性检测标准的对比

汽车驾驶舱内空气质量越来越受到广大消费者的关注,本文通过对部分品牌汽车地毯防霉性的测试方法及其优缺点分析,以及对常见地毯材质的防霉测试结果进行对比和说明,为整车厂防霉标准的制定及汽车地毯选材提供思路。

机车车辆制动电阻温升试验用轻量化测温系统的设计

针对轨道交通机车车辆制动电阻温升试验时温度测量的需求,设计了一款基于图形化编程语言LabVIEW的多通道温度测量系统,可以实现14通道的温度同时采集、显示、绘图及数据保存。为提高系统测量精度,以测量系统的实测值和标准源约定真值作为多项式拟合的数据源,采用最小二乘法曲线拟合的方法对测量系统进行标定,来降低测量误差、提高测量精度。测试结果表明,系统运行稳定可靠,测量精度显著提高。

沥青混合料OT试验研究进展与应用

反射裂缝显著影响沥青路面的寿命,但目前国际和国内尚缺少普遍认可的抗反射裂缝性能评价方法。Overlay Test(OT试验)是一种简单实用、高效快速、成本适宜、重复性较好的抗反射裂缝性能评价方法,研究改进后,有广泛应用的可行性。现综述了OT试验的起源和发展,阐明了目前面临的挑战,并对其可能的应用和研究方向进行了展望。结果表明,OT试验存在结果变异性问题,但相对优于其它疲劳试验方法,可通过规范试验流程、优化评价指标来得到改善。OT试验在反映路面开裂机理、指导工程实践、用作标准测试方法等方面具有应用价值,也可改进推广到钢桥面铺装、机场道面、铁路防水封闭层等其它场景。

基坑渗漏水土流失区的超高密度电阻率法探测数值模拟及试验研究

基坑开挖时常会发生渗漏涌水现象,危及基坑及其周边环境安全。基坑发生涌水险情时对渗漏与水土流失区域进行快速精准探测和针对性注浆封堵尤为重要。本文针对基坑渗漏与水土流失区域的低阻特性,尝试应用超高密度电阻率法实现基坑渗漏与水土流失区域精准定位。首先利用超高密度正反演软件ZZ-RINV2D得到渗漏与水土流失区域的地电响应规律,其次对发生渗漏险情的基坑进行探测试验。结果表明:超高密度电阻率应用于基坑渗漏与水土流失区域探测具有一定的可行性,反演结果结合地质资料能够快速圈定渗漏与水土流失区域的位置,为注浆封堵提供可靠的技术支持。

自平衡法在桩身竖向抗压承载力检测中的应用探讨

结合某钻孔灌注桩工程自平衡法检测桩身竖向抗压承载力应用实例,介绍自平衡法单桩静载荷检测试验原理,对依据规范进行检测和数据分析中遇到的问题进行探讨。自平衡点位置的确定是影响试验结果的关键,实际工程中可增加试桩数量,根据前桩试验情况对后桩平衡点位置进行及时调整,保证能够采用等效转换方式确定桩身极限承载力;依据规范进行等效转换计算时,在上段桩总位移小于下段桩总位移时,会存在某级荷载之后无法进行等效计算的情形;抗压摩阻力转换系数的选取对桩身抗压承载力计算结果影响较大,应结合勘察报告和当地经验合理取值,工程实际中可分别对不同抗压摩阻力转换系数给出不同极限承载力检值。