Evaluating the soil evaporation loss rate in a gravel-sand mulching environment based on stable isotopes data

In order to cope with drought and water shortages,the working people in the arid areas of Northwest China have developed a drought-resistant planting method,namely,gravel-sand mulching,after long-term agricultural practices.To understand the effects of gravel-sand mulching on soil water evaporation,we selected Baifeng peach(Amygdalus persica L.)orchards in Northwest China as the experimental field in 2021.Based on continuously collected soil water stable isotopes data,we evaluated the soil evaporation loss rate in a gravel-sand mulching environment using the line-conditioned excess(lc-excess)coupled Rayleigh fractionation model and Craig-Gordon model.The results show that the average soil water content in the plots with gravel-sand mulching is 1.86%higher than that without gravel-sand mulching.The monthly variation of the soil water content is smaller in the plots with gravel-sand mulching than that without gravel-sand mulching.Moreover,the average lc-excess value in the plots without gravel-sand mulching is smaller.In addition,the soil evaporation loss rate in the plots with gravel-sand mulching is lower than that in the plots without gravel-sand mulching.The lc-excess value was negative for both the plots with and without gravel-sand mulching,and it has good correlation with relative humidity,average temperature,input water content,and soil water content.The effect of gravel-sand mulching on soil evaporation is most prominent in August.Compared with the evaporation data of similar environments in the literature,the lc-excess coupled Rayleigh fractionation model is better.Stable isotopes evidence shows that gravel-sand mulching can effectively reduce soil water evaporation,which provides a theoretical basis for agricultural water management and optimization of water-saving methods in arid areas.

Optimization of Maturation of Radio-Cephalic Arteriovenous Fistula Using a Model Relating Energy Loss Rate and Vascular Geometric Parameters

The main reason for the early failure of radio-cephalic arteriovenous fistula (RCAVF) is non-maturity, which means that the blood flow rate in the fistula cannot increase to the expected value for dialysis. From a mechanical perspective, the vascular resistance at the artificially designed anastomosis causes an energy loss that affects blood flow rate growth and leads to early failure. This research studied how to maximize the RCAVF maturity and primary patency by controlling the energy loss rate. We theoretically analyzed and derived a model that evaluates the energy loss rate Eavf in RCAVF as a function of its blood vessel geometric parameters (GPs) for given flow rates. There was an aggregate of five controllable GPs in RCAVF: radial artery diameter (Dra), cephalic vein diameter (Dcv), blood vessel distance between artery and vein (h), anastomotic diameter (Da), and anastomotic angle (θ). Through this analysis, it was found that Eavf was inversely proportional to Dra, Dcv, Da, and θ, whereas proportional to h. Therefore, we recommended surgeons choose the vessels with large diameters, close distance, and increase the diameter and angle of the anastomosis to decrease the early failure of RCAVF. Simultaneously, we could explain the results of many clinical empiricisms with our formula. We found that increasing Dcv and θ was more significant in reducing Eavf than increasing Dra and Da. Based on our model, we could define two critical energy loss rates (CELa, CELb) to help surgeons evaluate the blood vessels and choose the ideal range of θ, and help them design the preoperative RCAVF plan for each patient to increase the maturity and the primary patency of RCAVF.

THE ANALYSIS OF CELL LOSS RATES IN AN ATM MUX WITH LOSS PRIORITIES

The analysis of cell loss rates in an ATM Mux with loss priorities is an important problem in the-study of traffic control in ATM networks. In this paper, the loss rates of the cells with different priorities in an ATM Mux are analyzed by approximating the actual input process with two-state MMDP and fluid flow technique, and the analytical expressions of the relation between the loss rates and the buffer size are obtained. Simulation shows that the approach is sulliciently accurate for applications.

Improvement of Water Use Efficiency in Winter Wheat byBreeding Lines with Low Rate of Water Loss of Excised-Leaves

A study was conducted with the objective of improvement of water use efficiency (WUE) and yield of winter wheat for Lowland Dryland Farming systems through a breeding approach. Various genotypes were screened in 1988 for rate of water loss of excised leaves (RWL) , followed by inter-crossing of diverse parents in 1993. Analysis of the relationship between RWL and yield components and plant traits demonstrated significant differences in RWL among genotypes. Under most circumstances, RWL was correlated negatively with yield and grain weight, and positively with plant height. The results demonstrated a basis for simultaneous selection for high yield and low RWL. It was found that genotypic rank varied with the duration of water loss. Correlation between RWL and yield was reduced by extended water loss duration. Analysis of the genetic variation and segregation of RWL of progenies and the effect of simultaneous screening for RWL and agronomic traits showed that good lines with improved yield and water use performance could be obtained.

Role of neutrino form factors in the energy loss rates of the pair annihilation process

The stellar energy loss rates due to the production of neutrino pairs e^(+)e^(-) → (W, Z, γ) → veve are calculated using the minimal extension of the Standard Model with the electromagnetic properties of the Dirac neutrinos, which takes the contributions of the neutrino charge radius, anapole moment, and dipole moments into account. We show that the contribution of the electron neutrino's dipole moment is small compared with that of the charge radius. The obtained results are also compared with the results obtained using the Standard Model.

A minimization problem of the risk probability in first passage semi-Markov decision processes with loss rates

This paper is the first attempt to investigate the risk probability criterion in semi-Markov decision processes with loss rates. The goal is to find an optimal policy with the minimum risk probability that the total loss incurred during a first passage time to some target set exceeds a loss level. First, we establish the optimality equation via a successive approximation technique, and show that the value function is the unique solution to the optimality equation. Second, we give suitable conditions, under which we prove the existence of optimal policies and develop an algorithm for computing ?-optimal policies. Finally, we apply our main results to a business system.

Metabolic rate and evaporative water loss in the silky starling （Sturnus sericeus）

To better understand the physiological characteristics of the silky starling(Sturnus sericeus), its body temperature(Tb), basal metabolic rate(BMR), evaporative water loss(EWL) and thermal conductance(C) elicited by different ambient temperatures(Ta)(5-30 °C) were determined in the present study. Our results showed that they have a high Tb(41.6±0.1 °C), a wide thermal neutral zone(TNZ)(20-27.5 °C) and a relatively low BMR within the TNZ(3.37±0.17 mL O2/g·h). The EWL was nearly stable below the TNZ(0.91±0.07 mg H2O/g·h) but increased remarkably within and above the TNZ. The C was constant below the TNZ, with a minimum value of 0.14±0.01 mL O2/g·h·°C. These findings indicate that the BMR, Tb and EWL of the silky starling were all affected by Ta, especially when Ta was below 20 °C and the EWL plays an important role in thermal regulation.

分离禽蛋壳膜粉碎装置刀片的设计与试验

为高效分离回收蛋壳膜,设计了一款采用剪切和碾压的粉碎方式专用于分离禽蛋壳膜的粉碎装置。采用干燥的蛋壳膜进行试验,通过理论分析和预试验确定刀片类型、刀片间隙、转子转速、筛网目数为主要影响因素,根据实际生产情况确定各因素的试验水平,以分离率和损耗率为评价指标进行四因素三水平响应面试验;利用Design-Expert 12.0对试验结果进行响应面分析,研究不同影响因素对评价指标的影响规律。验证试验结果表明:当调整转子转速为1374r/min、安装2目筛网、刀片间隙为1mm的50°剪切式刀片时,分离率为86.72%,损耗率为3.71%,大粒径蛋膜较多。试验装置有效提高了粉碎蛋壳膜后蛋膜的分离效果,降低了损耗率,具有极大的优越性。

基于PLC技术的联合收割机电气控制系统设计

以联合收割机电气控制系统为研究对象,利用可编程控制器(PLC)对联合收割机电气控制系统进行改进,以提高联合收割机运行效率和可靠性。通过对联合收割机的工作原理和液压作动系统进行分析,基于可编程控制器(PLC)进行联合收割机电气系统整体设计,并对电气系统的运行效果进行测试分析。试验结果表明:系统运行可靠,能够获得良好的收割效果,可将收割损失率控制在2%以内,验证了系统运行过程稳定性。

砂岩储层应力敏感性及其对单井产能的影响——以四川盆地JQ气田为例

近年来,四川盆地JQ气田致密砂岩储层展现出良好的勘探开发潜力。然而,在油气藏开发实践过程中,致密砂岩储层岩石存在应力敏感伤害,将影响气井产能。为了明确储层岩石应力敏感性及其对单井产能的影响,助力气藏的高效开发,针对四川盆地JQ气田中侏罗统沙溪庙组致密砂岩储层,在地层温度下开展变围压和变回压两种方式应力敏感性评价实验。结果表明:①变围压方式下储层岩石渗透率损失率在78.83%~95.85%,应力敏感普遍偏强。②变回压方式下储层岩石渗透率损失率在1.48%~64.02%,渗透率较低的样品,应力敏感表现为无~弱;渗透性越好,应力敏感越强。③6号砂体的应力敏感比8号砂体强。④应力敏感对气井产能有较为严重的影响,产量由1.75×10^(4)m^(3)/d降至0.17×10^(4)m^(3)/d,升降出口压力次数越多,获得的产量越低。因此,在制订生产措施时,渗透能力好的储层或压裂改造后的储层应选择合适的生产压差,防止在过高的生产压差下,喉道、裂缝提前闭合,尽可能降低应力敏感程度,提高单井产能和采收率,保障致密砂岩气藏的长期稳产。

原油裂解气资源评价的理论技术创新与评价应用——以四川盆地震旦系—寒武系为例

四川盆地震旦系—寒武系天然气资源丰富。近年来,在四川盆地川中古隆起和北部斜坡区先后获得了两个万亿级大气区的重大发现。为了明确该领域天然气的资源规模以及未来的勘探方向和创建一套切实可行的原油裂解气资源量的评估方法,本次研究基于该区天然气为古油藏原油裂解的基本认识,按照干酪根生油,再到古油藏裂解生气的技术路线对原油裂解气的资源量进行计算。应用成因法,采用PetroMod 3D盆地模拟软件,输入地层等厚图、岩相古地理图、烃源岩综合评价图、剥蚀量展布图以及生油动力学参数图版,建立整个盆地的三维地质模型,并切分为5个区块分别计算生油量,然后探讨了石油运聚系数、石油裂解率、天然气散失率以及寒武系石油运移的分配系数,并创建了天然气散失系数计算公式。在以上基础上,恢复了盆地及5个构造单元的生油史,并明确了古油藏形成的关键时刻,最终得到全盆地震旦系—寒武系常规天然气资源量为13.43×10^(12)m^(3),其中寒武系为5.43×10^(12)m^(3),震旦系为8.0×10^(12)m^(3)。并指出除了川中地区以外,川南和川东具有巨大的勘探潜力,尤其是位于川南地区德阳—安岳裂陷槽两侧的台缘带和台内颗粒滩是下一步勘探的现实领域。本次研究在理论创新和勘探实践中都具有重要意义。

钛合金铸锭冒口损失率差异性成因分析及对策研究

VAR熔炼的钛合金铸锭,熔炼末期需要采用补缩工艺制度,降低铸锭冒口损失率,提高成材率。在实际生产过程中,钛合金铸锭冒口损失率受各种因素影响,每个铸锭之间存在较大差异,且波动范围大,损失严重。为了分析钛合金铸锭冒口损失率差异性的影响因素,应用Minitab统计软件,采用多因子方差分析方法进行研究,找出了熔炼工班次、补缩时间班次、探伤操作者、补缩期操作稳定性、补缩过程是否频繁短路等显著影响因子,排除了不显著的因子交互作用,并针对各显著因子,制定了相应的改进对策,有效降低了钛合金铸锭冒口损失率以及铸锭间的差异性,提高了成品率。

基于集成树和MoE的馈线统计线损率双层估计模型

统计线损率是衡量电力系统经济运行的重要指标。然而,用户用电数据采集异常、数据传输中断等因素会导致统计线损率异常或缺失,这严重阻碍了智能配电网的线损精益化管理与经济高效运行。针对馈线统计线损率合理值的估计问题,该文提出了一种基于集成树和混合专家系统(MoE)的馈线统计线损率双层估计模型。首先,使用最大信息系数以更有效地分析统计线损率与其相关特征间的非线性关系,并采用鲁棒性强的K-Medoids聚类算法对馈线进行精细划分;然后,使用Stacking集成学习框架,基于基估计和元估计双层模型对馈线统计线损率进行两阶段估计,选用决策树和各类集成树模型作为基估计模型对统计线损率进行初步估计,将各基估计模型输出结果输入元估计模型MoE中进行最终估计,使用方均根误差(RMSE)和平均绝对误差(MAE)来衡量模型所估计统计线损率的合理性;最后,通过算例分析表明,与其他模型相比,该文所提馈线统计线损率双层估计模型具有更低的RMSE和MAE,对馈线统计线损率的估计效果更好。

玉米联合收获机清选控制系统设计与试验

玉米联合收获机清选系统工况复杂,存在收获质量差、效率不高等问题。基于此,设计一套清选损失率控制为主同时兼顾含杂率的自动控制系统。首先分析以风机转速、振动筛转速和喂入量为影响因素,损失率、含杂率为评价指标的正交试验数据,获取影响损失率和含杂率的主次因素,提出清选系统自动控制策略;其次,为开展控制策略和算法的研究,建立清选系统中的风机转速、振动筛转速调节装置以及收获机纵向运动的数学模型,设计离散化PID控制算法。最后,基于MATLAB/dSPACE软硬件环境,搭建清选控制系统的硬件在环仿真平台,并进行控制器在环测试。试验证明:本文设定的双目标联合控制策略和控制算法,能够有效降低清选损失率、含杂率,其中清选损失率降到2.7%左右,含杂率为2.8%左右。

Comparison of Success Rate and Radiological Bone Loss in Patients with Mini-Implant versus Conventional-Sized Implant Removable Prostheses: A Meta-Analysis

Background: The objective of this meta-analysis was to assess whether mini-implants have added benefit in terms of implants success rate and average bone loss over conventional-sized implants after one year of follow-up. Methods: An electronic search of randomized clinical trials was conducted in MEDLINE (via PubMed), Cochrane Central Register of Clinical Trials (CENTRAL) and Web of Science for studies including complete or partial edentulous patients requiring two or four mini-implants or conventional/ standard-sized implants in the maxilla or mandible for implant-supported removable prostheses who completed 12 months of follow-up. Results: The search provided 194 unique articles which were screened for title and abstract. Screening generated 12 articles which went through full-text analysis using eligibility criteria, and 4 articles were included for meta-analysis. Meta-analysis of these studies indicated a non-significant difference in the success rate between the two interventions (OR = 1.69 [0.74, 3.85;p = 0.21]). Bone loss estimates resulted in a significant bone reduction (Mean Difference = -0.74 [-0.95, -0.53;p < 0.05]) in favor of two mini-implants when compared with two conventional-sized implants, but when compared four mini- with two conventional-sized implants, the estimates were non-significant (Mean Difference = -0.24 [-0.69, 0.20;p = 0.29]). Conclusion: The current evidence does not provide solid evidence of the benefits of one intervention over the other. More studies with follow-up times of 10 and more years are needed as current studies have described the short-term outcomes.

基于产量损失率的气井合理配产方法研究

合理配产对气井生产具有非常重要的作用。现有的配产方法一般是按照无阻流量的1/6∼1/3来进行。在研究气体在地层中的非达西效应的基础上,提出了产量损失率的概念,通过量化非达西效应造成的产量损失,建立了气井产量损失率与无因次产量的图版。对于每一个配产,可得到与其相应的产量损失率,非达西效应对气井产量的影响就有了定量化的表征。因此,可根据产量损失率来进行合理配产。对于某些高压气藏,由于地层压力高,气体压缩程度大,地层条件下非达西效应并不强,产量损失率比较低,这类气井就可以将产量配高一些。该配产方法可实现量化储层气体非达西渗流损失,实现气井合理配产。该研究成果能在气井常规配产方法的基础上,进一步优化气井配产制度,更好地满足气井长期稳产、高效开发的需求,为气藏开发提供有益的借鉴。

加速碳化条件下不同养护制度对碱矿渣混凝土钢筋锈蚀的影响

研究了加速碳化环境(CO_(2)浓度为20%)下,标准养护、饱和Ca(OH)_(2)溶液养护和蒸压养护对CaO+Na_(2)CO_(3)为激发剂的碱矿渣混凝土(CNC)中钢筋锈蚀的影响。结果表明,与标准养护相比,饱和Ca(OH)_(2)溶液养护不改变CNC的水化产物,但使其早期水化更加充分,因此平均孔径减小;蒸压养护使CNC水化产物由C-S-H凝胶转化为水榴石与11-?型的托勃莫来石,平均孔径和总孔隙率显著减小。在相同的加速碳化龄期下,与标准养护相比,饱和Ca(OH)_(2)溶液养护和蒸压养护的CNC碳化深度降低、CNC中钢筋发生高概率锈蚀时间延缓、钢筋失重率下降。与相同养护条件下的普通硅酸盐混凝土相比,标准养护和饱和Ca(OH)_(2)溶液养护的CNC中钢筋抗锈蚀能力远小于普通硅酸盐混凝土,而蒸压养护的CNC中钢筋抗锈蚀能力大于普通硅酸盐混凝土。

无量纲化方法选择及最优无量纲化方法构建

文章针对综合评价过程中无量纲化方法难以选择的问题,首先,基于分布特征不变性和变异特征不变性对无量纲化方法进行初步筛选,结果发现,只有伸缩法能同时保持指标的分布特征和变异特征不变;其次,构建无量纲化有效性的统计检验方法,并检验各种伸缩法的有效性,结果发现,并非所有的伸缩法都能有效消除指标间的量纲差异;然后,建立无量纲化信息损失速率的度量模型,提出无量纲化方法选择的主要步骤,并以无量纲化应在有效消除指标间量纲差异的情况下尽可能减小指标内的信息损失速率为原则,构建一种最优无量纲化模型;最后,通过大量的数值模拟实验来进行无量纲化方法选择,并求解最优无量纲化模型。结果发现,基于以上步骤能更加科学准确地进行无量纲化方法选择;构建的最优无量纲化方法不同于任何一种现有的无量纲化方法,其不仅可以有效消除指标间的量纲差异,而且可以防止对数据的过度处理,造成不必要的信息损失。

盐冻耦合环境下再生砖粉ECC的耐久性研究

利用再生砖粉取代工程水泥基复合材料(ECC)中的石英砂,制备再生砖粉ECC,采用混凝土快速冻融试验,研究了氯盐、硫酸盐及复合盐(氯盐+硫酸盐)溶液侵蚀作用下再生砖粉ECC的质量损失率和相对动弹性模量变化规律,建立了ECC在盐冻侵蚀环境下的损伤模型,并对其耐久性进行评价。结果表明:冻融循环300次后,再生砖粉ECC在清水、氯盐、硫酸盐及复合盐四种介质中的质量损失率分别为2.884%、4.984%、1.955%和6.891%,相对动弹性模量分别下降了6.468%、16.300%、24.303%和39.861%;再生砖粉ECC在单一盐冻情况下的抗冻等级大于F300,在复合盐冻情况下的抗冻等级大于F250,具有良好的抗盐冻性能;建立的冻融损伤模型可较好地反映ECC在不同冻融介质下的损伤度Dn与冻融循环次数的关系,可以为严寒地区的结构耐久性设计提供有效参考。