LUBRICATION FILM FORMATION MECHANISM OF SLIPPER PAIRS IN LOW SPEED HIGH TORQUE HYDRAULIC MOTORS

Pressure-flow analytical formulas of lubrication film of slipper pairs on camshaft connecting rod type low speed high torque （LSHT） hydraulic motors are put forward. The bottom surface of slipper pairs is rectangle, and the effect of squeeze flow and pressure differential flow is considered. The dynamic process of lubrication film formation through squeezing is numerically studied by computer simulation. Effects of supply pressure, initial lubrication film thickness, velocity damping coefficient, loading impact and gravity, etc are studied. Advantages of novel slipper pairs with large oil cavity area are pointed out.

Risk evaluation of natural disasters based on connection function

There are many uncertain factors,such as stochastic,fuzzy and gray information in the risk analysis on natural hazard.The set pair analysis(SPA)deals effectively with the various uncertain factors contributing to evaluation of the risk level of natural disasters.The evaluation indicators and standards of natural disasters risk are analyzed by identity-discrepancycontrary(IDC).The result,the connection numbers,still has uncertainty information.Thus,yielding the risk evaluation model of natural disasters based on connection function,which construct a set pair relation between the indicators of connection numbers and comprehensive evaluation standards,and describe uncertainty of the connection numbers by using connection function.The study showed that the proposed model takes into account only the uncertainty of risk evaluation indicator identification on natural disasters,also the uncertainty of result connection numbers.This approach gives full consideration to the uncertainty of systematic evaluation process along with the actual meaning of comprehensive evaluation functions.Therefore,this means it is able to reduce the uncertainty of final evaluation results and improve the accuracy and reasonability of evaluation results.This model is capable of reflecting actual situation of the risk evaluation on natural disaster affected by various uncertain factors and has a promotional value in the natural disaster risk assessment.

A Research for Regional Contribution Rate of Internal Source and External Source of PM_(2.5) Based on Set Pair Analysis Method

A problem of the air pollution control in China is getting to know a regional contribution rate of internal and external source of PM2.5. In this paper,Set Pair Analysis（ SPA） method is proposed to calculate the contribution rate of PM2.5in Dongguan City. Due to geographic,meteorological factors and the low concentration of air pollutants in Qingxi area,the PM2.5in this place is mainly contributed by the regional transport of air pollutants from other inside areas of Dongguan,and less affected by the outside of Dongguan. So the concentration of PM2.5in Qingxi area can reflect the Dongguan＇s basic background concentration of PM2.5. On the basis of the basic background concentration,firstly the concentration of each pollutant components is divided into the internal part and the mixed part. Secondly using the source apportionment samples of five monitoring sites in Dongguan we can respectively construct a sample set A and an evaluation set B. Thirdly the SPA is operated onto the mixed part in terms of set B.At last the connection degree between the concentration of each pollutant components and external source and internal source will be calculated,that is the contribution rate. The research reveals that the contribution rate of internal source and external source of PM2.5in Dongguan City is 83%and 17% respectively,which roughly met expectations. This method is simple and effective and it can provide a reference for the government taking reduction measures to control PM2.5pollutants emission.

Exploration and determination of the principles of rotary-percussive underground slimhole drilling

A possibility of the efficient use of rotary percussive drilling to provide drilling smaller diameter holes(40–70 mm) both in mining and prospecting is disclosed herein. A new construction designed for the nipple thread connection is described. The relative amplitude variation, change of power pulse time and energy in their propagation throughout the drilling tool are determined. A possibility of the efficient power pulse transfer along the drill string to the rock destruction tools with new nipple connections which allow automating the make-up and breakout system of drill pipe was supported by experiments.

Notes concerning Codazzi pairs on almost anti-Hermitian manifolds

Let∇be a linear connection on a 2n-dimensional almost anti-Hermitian manifold M equipped with an almost complex structure J,a pseudo-Riemannian metric g and the twin metric G=g◦J.In this paper,we first introduce three types of conjugate connections of linear connections relative to g,G and J.We obtain a simple relation among curvature tensors of these conjugate connections.To clarify the relations of these conjugate connections,we prove a result stating that conjugations along with an identity operation together act as a Klein group,which is analogue to the known result for the Hermitian case in[2].Secondly,we give some results exhibiting occurrences of Codazzi pairs which generalize parallelism relative to∇.Under the assumption that(∇,J)being a Codazzi pair,we derive a necessary and sufficient condition the almost anti-Hermitian manifold(M,J,g,G)is an anti-K¨ahler relative to a torsion-free linear connection∇.Finally,we investigate statistical structures on M under∇(∇is a J−parallel torsion-free connection).

基于SPA的涂料企业重大危险源安全风险评价

提出了一种针对涂料企业重大危险源安全风险等级的评价模型,从固有危险因子和危险抵消因子两个方面,构建了重大危险源评价指标体系,采用组合赋权判断各级指标权重,通过集对分析法(SPA)建立联系数函数,求出各指标单项联系数和整体联系数,以此为依据判定重大危险源的安全风险等级。结果表明:此模型可有效地解决评价中存在的重大危险源定量困难的难题,评价结果既能对企业安全状况作出分析,又能对企业未来的安全趋势作出合理的预测,可以为重大危险源的安全监管和事故预防工作提供理论支持。

Application of Improved SPA Method in the Comprehensive Assessment of Groundwater Environment Quality:A Case Study of Jinjiang, Fujian Province

This paper applied the set pair analysis with improved five-element connection degree to assess shallow groundwater quality of Jinjiang City, Fujian Province, and used map to show the spatial distribution. The assessment results showed that most groundwater in the district was in the grade I and II, i.e. the overall groundwater environment in this area was favorable; groundwater of grade III(poorer level) was mainly distributed in Dongshi Town in the coastal region, and the total area was smaller. Major out-of-limit factors are TDS, nitrate, nitrite, ammonia nitrogen, and chloride, therefore, industrial and agricultural development, human activities and seawater invasion were major causes for the aggravation of water quality.

150t BOF-LF-RH-CC-CR工艺试制石油钻杆连接套用钢SAE4137M

本钢采用铁水预处理-150t复吹转炉-LF-RH-350mm×470mm连铸、M-EMS-连轧工艺生产φ130～170 mm石油钻杆连接套用钢SAE4137M(/%:0.35～0.38C、0.15～0.35Si、0.85～1.00Mn、≤0.015P、≤0.008S、0.90～1.20Cr、0.28～0.33Mo、≤0.005Ca、≤0.0090N)。通过转炉出钢过程加复合脱氧剂,LF扩散脱氧全程吹氩搅拌,RH"软吹氩",严格控制喂钙线量,控制连铸钢水过热度20～30℃,使钢材中氧含量为(13～15)×10^(-6),氢含量(0.4～0.5)×10^(-6),氮含量为(35～44)×10^(-6),残余钙含量(12～18)×10^(-6),并保证钢中Al/N≥2,满足石油用钢的要求。

Debris Flow Hazard Assessment Using Set Pair Analysis Models:Take Beichuan County as an Example

Assessment of debris flow hazards is important for developing measures to mitigate the loss of life and property and to minimize environmental damage. Two modified uncertainty models, Set Pair Analysis(SPA) and modified Set Pair Analysis(mSPA), were suggested to assess the regional debris flow hazard. A case study was conducted in seven towns of the Beichuan county,Sichuan Province, China, to test and compare the application of these two models in debris flow hazard assessment. The results showed that mSPA only can fit for value-variables, but not for non value-variable assessment indexes, Furthermore, as for a given assessment index xi, mSPA only considers two cases,namely, when grade value increases with xi and when grade value decreases with xi. Thus, mSPA can not be used for debris flow hazard assessment but SPA is credible for the assessment because there are no limitations when using SPA model to assess the debris flow hazard. Therefore, in this study SPA is proposed for assessing debris flow hazard.

Method to determine α in rough set model based on connection degree

An improvement of tolerance relation is proposed in regard to rough set model based on connection degree by which reflexivity of relation can be assured without loss of information. Then, a method to determine optimal identity degree based on relative positive region is proposed so that the identity degree can be computed in an objective method without any preliminary or additional information about data, which is consistent with the notion of objectivity in rough set theory and data mining theory. Subsequently, an algorithm is proposed, and in two examples, the global optimum identity degree is found out. Finally, in regard to optimum connection degree, the method of rules extraction for connection degree rough set model based on generalization function is presented by which the rules extracted from a decision table are enumerated.

Efficiency Evaluation for the Annual Equipment Maintenance Based on Set Pair Analysis

Most traditional assessment methods, which have complicated mathematic formulas,are difficult for calculation and application in system efficiency evaluation. A new approach to annual equipment maintenance system efficiency assessment,the set pair analysis method( SPAM),has been proposed based on the principle of set pair analysis( SPA). Firstly,the evaluation index system of the annual equipment maintenance is proposed. Secondly,the evaluation model of the annual equipment maintenance efficiency based on the SPAM is built. Then the application processes of the SPAM are introduced. At the end of the paper,a real application example is given. The results of the application indicate that the proposed model is feasible and effective. It can give strong supports to improve the evaluation effect of the unit equipment maintenance support.

A Project Risk Ranking Approach Based on Set Pair Analysis

Set Pair Analysis (SPA) is a new methodology to describe and process system uncertainty. It is different from stochastic or fuzzy methods in reasoning and operation, and it has been applied in many areas recently. In this paper, the application of SPA in risk ranking is presented, which includes review of risk ranking, introduction of Connecting Degree (CD) that is a key role in SPA., Arithmetic and Tendency Grade (TG) of CDs, and a risk ranking approach proposed. Finally a case analysis is presented to illustrate the reasonability of this approach. It is found that this approach is very convenient to operate, while the ranking result is more comprehensible.

Paired, Total, and Connected Domination on the Queen’s Graph Revisited

The question associated with total domination on the queen’s graph has a long and rich history, first having been posed by Ahrens in 1910 [1]. The question is this: What is the minimum number of queens needed so that every square of an n × n board is attacked? Beginning in 2005 with Amirabadi, Burchett, and Hedetniemi [2] [3], work on this problem, and two other related problems, has seen progress. Bounds have been given for the values of all three domination parameters on the queen’s graph. In this paper, formations of queens are given that provide new bounds for the values of total, paired, and connected domination on the queen’s graph, denoted , , and respectively. For any n × n board size, the new bound of is arrived at, along with the separate bounds of , for with , and , for with .

New design method of unequal taper thread(UTT)pairs and its application in API NC38 thread improvement

API standard threads are the most commonly used thread configurations for drill pipe joints in the petroleum industry.Recently with the increasing application of horizontal wells and extended-reach wells in drilling engineering,drill pipe joint threads are subjected to complex loads,and drill pipe joint thread breakage accidents occur frequently.The API NC38 threaded pair used in the SU36-8-4H2 well suffered a fracture accident.Macroscopic analysis found that the fracture sites were located near the root of the first engagement pin-thread where the stress was greatest.Therefore,it is necessary to find an alternative method to reduce the largest stress of NC38 threads.Then,a new design method of unequal taper thread(UTT)pairs is proposed that the taper of pin thread,slightly smaller than the taper of matched-box thread,is not equal to one of box-thread.In the UTT pairs of API NC38 thread,the taper of box thread is kept as the standard taper of 1:6,but the taper of pin thread is,respectively,1:6.1(UTT-I),1:6.2(UTT-Ⅱ),1:6.3(UTT-Ⅲ)and 1:6.4(UTT-IV).The 3D finite element models of four UTT pairs and one standard pair based on NC38 thread were developed,and the mechanical properties of five thread pairs bearing such typical working loads as torque,axial compression,axial tension,bending moment,internal and external pressure,were analyzed.The results show that four UTT pairs are superior to the standard pair of API NC38,and UTT-Ⅲ has the most performance in all of four UTT pairs.Compared with the standard pair of API NC38,UTT-Ⅲ pair can improve the bearing capacity such as torsion strength,compression strength,tensile strength,bending strength,strength against internal and external pressure,by 24.8%,13.2%,22%,9.99%and 14.2%,respectively.The new design method of UTT pair enhances the bearing capacity of API NC38 thread,and has been applied in Changqing Drilling Company of CNPC Chuanqing Drilling Engineering Company Limited.The UTT-thread pair method is not only applicable for API series threads to improve the connection performance,but also suitable for various non-API taper connection threads to promote existing working ability such as air tightness,stress corrosion resistance,fatigue resistance et al.

基于相对联系数的区域水利高质量发展评价指标体系筛选方法

为综合判断在区域水利高质量发展目标、发展途径、发展条件相互作用下区域水资源-经济社会-生态环境复合系统不断协同优化的系统高质量发展水平状态,构建了由发展目标、发展途径和发展条件3个子系统组成的区域水利高质量发展初步评价指标体系。为定量分析初步评价指标体系的专家咨询信息,根据专家指标排序合理性模糊关系的取值区间特点提出了相对联系数,用相对联系数的平均集对势估计各专家指标排序合理性的权重,进而可得各指标重要性的专家综合排序值,据此筛选初步评价指标体系,构建了基于相对联系数的区域水利高质量发展评价指标体系筛选方法(SM-RCN)。SM-RCN在陕西省的应用结果表明:筛选后的指标体系汇聚了各专家对区域水利高质量发展主要影响指标的综合评判;SM-RCN可克服评价指标体系构建过程缺乏定量分析依据的不足,可识别不同专家、同一专家对不同评价方面的指标排序合理性的程度。该筛选方法在区域水利现代化、水资源空间均衡、水资源承载力等评价指标体系构建过程中具有应用前景。

水资源集对系统中的对立关系分析

水资源集对系统中同一项和对立项构成的对立关系是水资源集对分析辩证思维的集中体现,是构建集对系统联系数的基石。通过五种常见对立关系类型的概念解析与其应用之间对应关系的分析,以及面向五类对立关系的水资源集对系统差异项不确定性分析,在对立关系复杂、深刻的涵义方面取得了一些新的认识:在水资源集对系统中常见的反比型、互斥型、正负型、互补型和虚实型对立关系可分别由模糊、随机、涨落、分配和存在型不确定性对应产生并进行分析计算;在集对系统中最基本的对立关系是反比型、互斥型对立关系,对应的模糊性、随机性是事件发生的内容性质、事件发生的结果数量方面的不确定性;差异项不确定性的变化是导致联系数中同异反三类关系变化的原因,是“一分为三”辩证思维的一种典型展开,反映了量变到质变的转化规律;在差异项表征的五类不确定性中最常见的是模糊不确定性,模糊不确定性变量的运算可通过随机模拟技术转化为随机不确定性变量的运算。模糊和随机的不确定性分析分别注重物理内涵解析和数学定量计算,这反映了水资源集对分析学科属于计算思维领域,对进一步推动模糊水文学、随机水文学、水资源集对分析、结构水资源学等学科发展无疑具有明显的启发作用和指导意义。

饱和盐水防塌冲洗液体系在瑞13A采卤对接井中的应用

瑞13A井是建立一进两出或两进一出的采卤方式采卤的一口绿色矿山采卤对接井,设计井深1138.3 m,实际完钻井深1285 m。主要地层为新统官庄组、丰县组、古近系,主要岩性为粉砂岩、泥岩与泥质胶结为主的细砂岩、泥灰岩。夹有一套含有盐类矿物的沉积岩系,岩石类型主要为氯化物岩、硫酸盐岩(硬石膏、钙芒硝)、碳酸盐岩(白云石)及泥质岩、粉砂岩。施工过程中存在坍塌、掉块、摩擦阻力大、地层易缩径等复杂难题。现场优选了YZ(高效抑制剂)、RH(高效润滑剂)等,形成了饱和盐水强抑制防塌冲洗液体系,密度1.25~1.35 g/cm^(3)可调,润滑系数<0.1,滤失量≤5 mL,流变性能好,抑制防塌效果好,取得了较好应用效果,保证了项目的顺利实施。

基于集对分析的区域水利高质量发展评价方法

基于发展目标、发展途径、发展条件相作用形成的区域水利高质量发展系统结构和相对联系数的指标体系筛选方法,构建了由59个评价指标、11个发展方面、3个发展子系统组成的区域水利高质量发展评价指标体系;利用专家咨询和遗传层次分析法确定各指标权重,采用集对分析计算指标、方面、子系统和样本4个层次与区域水利高质量发展评价标准集对间的联系数,应用减法集对势判断4个层次区域水利高质量发展状态,建立了基于集对分析的区域水利高质量发展评价方法(SPA-HDEM),并将其应用于陕西省2020年10个地市的水利高质量发展评价中。结果表明:西安水利高质量发展状态处于中等偏较高等级,咸阳、汉中、渭南、安康、宝鸡、榆林均处于中等等级,延安、商洛、铜川均处于较低偏中等等级;非陕南的7个地市的发展条件均不佳,10个地市的发展途径均相对较低;各地市处于反势的指标中,西安有“人均水资源量”等11个、铜川有“防洪堤防达标率”等32个、宝鸡有“水利投资占GDP比重”等16个、咸阳有“人均生活用水量”等14个、渭南有“水资源开发利用率”等19个、延安有“供水模数”等21个、榆林有“供水模数”等22个、汉中有“防洪堤防达标率”等15个、安康有“防洪堤防达标率”等21个、商洛有“人均工资”等25个,重点调控这些反势指标是全省水利高质量发展工作中的重要任务。SPA-HDEM适用性强,在已知评价等级标准的实际区域水利高质量发展评价问题中具有应用前景。

S135钻杆接头螺纹三维参数化建模及力学特性分析

S135钢级钻杆在矿井勘探、探放水、瓦斯抽采等钻孔施工中得到了广泛使用。然而,由于钻杆接头螺纹承受轴向拉压、扭转、弯曲及其复合载荷的循环作用,导致接头螺纹的使用寿命远远低于其设计寿命,是整个钻杆结构中最薄弱的环节。因此,通过万能拉伸试验获得钻杆接头材料的力学性能参数,经计算转化得到其本构参数,对钻杆接头进行有限元分析。为了提高有限元分析效率,推导垂直于钻杆接头轴线的螺纹截面轮廓几何表达式,基于旋转、抬升、缩径和连接节点的设计思路,提出了一种考虑钻杆接头锥度和台肩的三维螺纹参数化建模方法,并根据单元和节点之间的关系开发了钻杆接头连接的参数化三维六面体网格建模程序,通过与交互式建模方法计算结果的对比验证了其有效性和可行性。此外,对上扣扭矩、压扭及压弯扭复合载荷作用下接头外螺纹的力学特性进行了分析。结果表明:3种工况下钻杆接头外螺纹上的应力近似呈现“浴盆”形态,第1螺纹牙上的应力最大;随着圈次的增加,螺纹牙上的应力迅速下降,最后一圈螺纹牙上的应力呈现上升趋势;在弯矩的作用下,螺纹牙上的应力具有非对称特征。在接头螺纹设计时,必须考虑井眼曲率的影响并且需要重点关注接头压缩边第1螺纹牙上的应力。