Effects of combined drip irrigation and sub-surface pipe drainage on water and salt transport of saline-alkali soil in Xinjiang, China

Developing effective irrigation and drainage strategies to improve the quality of saline-alkali soil is vital for enhancing agricultural production and increasing economic returns. In this study, we explored how irrigation and drainage modes (flood irrigation, drip irrigation, and sub-surface pipe drainage under drip irrigation) improve the saline-alkali soil in Xinjiang, China. We aimed to study the transport characteristics of soil water and salt under different irrigation and drainage modes, and analyze the effects of the combination of irrigation and drainage on soil salt leaching, as well as its impacts on the growth of oil sunflower. Our results show that sub-surface pipe drainage under drip irrigation significantly reduced the soil salt content and soil water content at the 0–200 cm soil depth. Under sub-surface pipe drainage combined with drip irrigation, the mean soil salt content was reduced to below 10 g/kg after the second irrigation, and the soil salt content decreased as sub-surface pipe distance decreased. The mean soil salt content of flood irrigation exceeded 25 g/kg, and the mean soil desalination efficiency was 3.28%, which was lower than that of drip irrigation. The mean soil desalination rate under drip irrigation and sub-surface pipe drainage under drip irrigation was 19.30% and 58.12%, respectively. After sub-surface drainage regulation under drip irrigation, the germination percentage of oil sunflower seedlings was increased to more than 50%, which further confirmed that combined drip irrigation and sub-surface pipe drainage is very effective in improving the quality of saline-alkali soil and increasing the productivity of agricultural crops.

Heavy Metals Removal from Swine Wastewater Using Constructed Wetlands with Horizontal Sub-Surface Flow

The removal efficiency of Cu and Zn from swine wastewater was evaluated as effected by three variables: the hydraulic retention time (HRT) (24, 48, 72 and 96 hours), two different plant species (Typha domingensis Pers. and Eleocharis cellulosa) and two different sizes of filter media (5 and 15 mm) using a horizontal sub-surface flow constructed wetland. From the results, a significant difference was observed in the removal efficiency of Cu and Zn with respect to different hydraulic retention times. The best results were obtained in the HRT of 96 hours for Zn where 96% removal of Zn with Typha domingensis Pers. specie with gravel of 15 mm (experimental unit 6) was achieved. For Cu, at 72 hours of HRT, the efficiency was nearly 100% in five of the six study units (1, 2, 3, 5 and 6). In contrast, in experimental unit 4 with gravel of 15 mm and without plants, only 86% Cu removal was achieved.

A sub-surface eddy at inertial current layer in the Canada Basin,Arctic Ocean

An Arctic Ocean eddy in sub-surface layer is analyzed in this paper by use of temperature, salinity and current profiles data obtained at an ice camp in the Canada Basin during the second Chinese Arctic Expedition in summer of 2003. In the vertical temperature section, the eddy shows itself as an isolated cold water block at depth of 60 m with a minimum temperature of - 1.5℃, about 0.5℃ colder than the ambient water. Isopycnals in the eddy form a pattern of convex, which indicates the eddy is anticyclonic. Although maximum velocity near 0.4 m s^-1 occurs in the current records observed synchronously, the current pattern is far away from a typical eddy. By further analysis, inertial frequency osci/lations with amplitudes comparable with the eddy velocity are found in the sub-surface layer currents. After filter the inertial current and mean current, an axisymmetric current pattern of an eddy with maximum velocity radius of 5 km is obtained. The analysis of the T-S characteristics of the eddy core water and its ambient waters supports the conclusion that the eddy was formed on the Chukchi Shelf and migrated northeastward into the northern Canada Basin.

Sound Scattering From Rough Bubbly Ocean Surface Based on Modified Sea Surface Acoustic Simulator and Consideration of Various Incident Angles and Sub-surface Bubbles＇ Radii

The aim of the present study is to improve the capabilities and precision of a recently introduced Sea Surface Acoustic Simulator(SSAS) developed based on optimization of the Helmholtz–Kirchhoff–Fresnel(HKF) method. The improved acoustic simulator, hereby known as the Modified SSAS(MSSAS), is capable of determining sound scattering from the sea surface and includes an extended Hall–Novarini model and optimized HKF method. The extended Hall–Novarini model is used for considering the effects of sub-surface bubbles over a wider range of radii of sub-surface bubbles compared to the previous SSAS version. Furthermore, MSSAS has the capability of making a three-dimensional simulation of scattered sound from the rough bubbly sea surface with less error than that of the Critical Sea Tests(CST) experiments. Also, it presents scattered pressure levels from the rough bubbly sea surface based on various incident angles of sound. Wind speed, frequency, incident angle, and pressure level of the sound source are considered as input data, and scattered pressure levels and scattering coefficients are provided. Finally, different parametric studies were conducted on wind speeds, frequencies, and incident angles to indicate that MSSAS is quite capable of simulating sound scattering from the rough bubbly sea surface, according to the scattering mechanisms determined by Ogden and Erskine. Therefore, it is concluded that MSSAS is valid for both scattering mechanisms and the transition region between them that are defined by Ogden and Erskine.

Quantitative relations between blowhole and coating components of stainless steel electrode

Using uniform design method and computer program, the experiment has been arranged, the mathematical model between blowhole resistance of stainless steel electrode and 12 coating components has been regressed. And the trend diagrams of effects of. every ingredient on the blowhole resistance have been drawn out. The mathematical model and trend diagrams revealed the complex laws between the mark of blowhole resistance and coating components. The effect of each ingredient on the mark of blowhole resistance is different, such as the mark of blowhole resistance increases with calcite increases. There are interactions among the coating components, such as the mark of blowhole resistance decreases with fluorite increases when calcite content is lower; but it increases when calche content is higher. The sieving and forecasting can be done using mathematical model and computer program.

Optimizing the Interpretation of Sub-surface Resistivity in Relation with Borehole Productivity in Basement Area Applied to Seno Province （Burkina Faso）

This study aims at identifying possible correlations between shapes, types of geophysical anomalies and borehole productivity according to geological and hydrogeotogical contexts. The methodology adopted was a two-pronged one--the first step sought to： （1） interpret the electrical resistivity values from horizontal profiling and vertical electrical sounding implemented in Seno province that preceded the drilling of 513 boreholes; （ii） interpret data from pumping tests carried out on boreholes having a discharge superior to 1 m3/h （＂positive borehole＂） by using Cooper-Jacob＇s method. In the second step, according to geology, authors tried to identify possible correlations between each of the qualitative geophysical parameters： ~shape of anomaly〉〉, tttype of anomaly〉〉 and ~〈type curve〉〉 on the one hand, and hydrogeological parameters such as discharge, alteration thickness, transmissivity and saturated level on the other. The results of this study have shown that the chances of having a positive borehole in Seno province are higher when the type of anomaly is TCC （80%）, shape of anomaly is ＂W＂ and when type curve is ＂H＂ （80%） for all geological formations. Granitic formations are those that record higher discharges while schists record high transmissivity values.

Sub-Surface Drip Irrigation in Associated with H_(2)O_(2) Improved the Productivity of Maize under Clay-Rich Soil of Adana, Turkey

Maize being sub-tropical crop is sensitive to water deficit during the early growth stages;particularly clay-rich soil,due to the compaction of the soil.It is well-documented that potential sub-surface drip irrigation(SDI)(Full irrigation;SDIFull(100%field capacity(FC)),Deficit irrigation;SDIDeficit(70%FC))improves water use efficiency,which leads to increased crop productivity;since it has a constraint that SDI excludes soil air around the root-zone during irrigation events,which alter the root function and crop performance.Additionally,in clay-rich soils,the root system of plants generally suffers the limitation of oxygen,particularly the temporal hypoxia,and occasionally from root anoxia;while SDI system accomplishes with the aerating stream of irrigation in the rhizosphere could provide oxygen root environment.The oxygen can be introduced into the irrigation stream of SDI through two ways:the venturi principle,or by using solutions of hydrogen peroxide through the air injection system.Therefore,the application of hydrogen peroxide(H_(2)O_(2);HP)can mitigate the adverse effect of soil compactness and also lead to improving the growth,yield and yield attributes of maize in clay-rich soil.Considering the burning issue,a field study was conducted in consecutive two seasons of 2017 and 2018;where hybrid maize was cultivated as a second crop,to evaluate the effect of liquid-injection of H_(2)O_(2)(HP)into the irrigation stream of SDI on the performance of maize in a clay-rich soil field of Adana,Turkey.When soil water content decreased in 50%of avail-able water,irrigation was performed.The amount of water applied to reach the soil water content to the field capacity is SDIFull(100%FC)and 70%FC of this water is SDIDeficit(70%FC).In the irrigation program,hydrogen peroxide(HP)was applied at intervals of 7 days on average according to available water with and without HP:SDIFull(100%FC)+0 ppm HP with full SDI irrigation;SDIFull(100%FC)+250 ppm HP with deficit SDI irrigation;SDIDeficit(70%FC)+0 ppm HP,SDIDeficit(70%FC)+250 ppm HP and SDIDeficit(70%FC)+500 ppm HP.Deficit irrigation(SDIDeficit(70%FC))program was started from tasseling stage and continued up to the physiological maturity stage with sub-soil drip irrigation.H_(2)O_(2) was applied 3 times during the growing season.Two years’results revealed that the liquid-injection of H_(2)O_(2) into the irrigation stream of SDI improved the growth and yield-related attributes and grain yield of maize.Based on the obtained results,during the extreme climatic condition in the year 2017,SDIFull(100%FC)+250 ppm HP was more effective than SDIFull(100%FC)+0 ppm HP on all traits for relative to full irrigation.While,during the favourable climatic condition in the 2018 season,SDIFull(100%FC)+250 ppm HP was more effective than full irrigation with SDIFull(100%FC)+0 ppm HP for the grain yield,grains,and SPAD value.Accordingly,the most effective treatment was SDIFull(100%FC)+250 ppm HP,as it gave the highest growth and yield-related attributes and grain yield of maize followed by SDIDeficit(70%FC)+250 ppm HP.Therefore,SDIFull with 250 ppm H_(2)O_(2) using as liquid-injection may be recommended to mitigate the adverse effect of soil compactness particularly water-deficit stress in clay-rich soil for the sustainability of maize production.

铝合金缸盖重力铸造顶注式工艺分析与应用

铝合金缸盖是汽车发动机上的核心部件,尺寸精度及力学性能要求较高。针对EZ缸盖复杂结构和铸造成形难等特点,开展了重力顶注式铸造工艺的研究与验证,通过重力顶注半封闭式浇注系统、冒口、组合砂芯等设计以及产品结构细节优化和浇注工艺改进与验证;生产验证表明,铸件X射线探伤及T6热处理后力学性能等检测结果均满足技术要求,为批量生产合格铸件提供保障。

基于CAE分析的铝合金二合一壳体压铸工艺设计与优化

介绍了某新能源汽车二合一壳体结构特点。设计了初始压铸工艺并进行试产。借助CAE软件对壳体试件局部缺陷进行深入研究,分析其产生原因,确定了浇注系统优化改进方向,解决了铸件内部气孔和渣孔缺陷。

一种小型变速箱体气孔缺陷成因分析及对策

结合生产实际分析了某款变速箱体局部气孔缺陷产生的原因,通过采取增强铸型排气能力、降低铁液流动阻力等多方面的改进措施,有效降低了变速箱体局部气孔缺陷发生比例,降低了铸件生产成本,提高了铸件外观质量。

一种小型连体缸盖的铸造工艺

研究一种三缸连体缸盖在生产过程中出现的气孔、内腔披缝、断芯等铸造问题。通过减小底注截面积、降低浇注温度、采用发气量低透气性好的涂料等措施解决了气孔问题。利用低温固化工艺等解决了砂芯变形导致的披缝问题。通过制芯预填芯砂并设计制作二次组芯辅助装置等措施解决断芯问题。通过工艺改进,产品的质量由15%的废品率降至5%以下。

气缸体气孔缺陷产生原因及预防措施

分析了WP10气缸体铸造过程中气孔缺陷产生的条件和原因。气孔主要集中在上箱(最后凝固位置),表现为表面或近表面大小不等的圆形、长形或不规则形气孔。通过控制型芯发气量、优化浇注温度和速度、增加压边出气冒口以及改进浇注系统等措施,有效抑制了气孔缺陷的产生,显著提高了铸件质量。

大型复杂结构铸件表面气孔缺陷解决对策

以一种大型机体气孔缺陷为例,总结了复杂结构机体上表面气孔缺陷的解决方法。通过铸造仿真模拟分析了气孔缺陷形成机理,主要原因为:(1)铁水到达上表面时温度降低至1210℃附近,不利于侵入性气体上浮排出;(2)机体上表面缺少纵向排气通道、气眼和溢流冒口;(3)凸轮轴上部为拱形薄壁结构,浇注后期铁水粘稠,气体流动不畅无法顺利排出。通过改进机体上表面结构、提高排气能力等方案,解决了铸件表面气孔缺陷。

气缸体铸件排气工艺设计的应用研究

基于气缸体铸件浇注系统排气工艺设计,通过对厚大砂芯掏空减重,减少砂芯发气量,并结合铸件结构和造型工艺考虑砂型、砂芯排气及补缩能力,有效解决铸件浇注过程中排气问题,减少铸件气孔等缺陷。

H13钢电渣锭起弧端气孔产生原因与控制

H13模具钢是热作模具钢中应用最为广泛的材料之一。我国正处在模具钢产品飞速发展阶段,产品性能与国际先进企业相比存在较大差距,提高产品质量、降低生产成本、提高竞争力是模具钢企业发展的重中之重。张宣科技在完成特材产线建设后,将H13模具钢作为主研产品,但在研发过程中电渣锭起弧端内部出现气孔现象,气孔直径6~20 mm,数量较多且分布不均匀,无法满足下道工序对坯料钢锭的制备要求,只能通过切除电渣锭起弧端气孔后方可使用,造成了电渣锭起弧端切损大、成材率低、成本居高不下的情况。为此,张宣科技分析了H13模具钢电渣锭起弧端气孔产生的原因,对原辅料、设备、生产准备工艺进行筛查试验,找到了气孔产生的关键原因是氢含量高,并提出渣料烘烤、电极锭制备、设备设施干燥、优化起弧化渣工艺和渣系等措施。通过不断试验及生产工艺优化,彻底消除了H13模具钢电渣锭起弧端内部气孔缺陷,电渣锭产品质量得到大幅提升,电渣锭成材率提高近10%。

钢板边裂缺陷原因分析及整改措施研究

利用金相显微镜、扫描电镜、能谱仪等相关试验手段,研究了钢板边裂缺陷原因,结果表明:引起钢板边裂的原因基本分为四种:夹杂物引起的边裂,钢板边部脱碳严重引起的边裂,横向冷却不均匀引起的边裂和聚集的气泡引起的边裂。针对相关原因通过采取优化炼钢工艺、连铸工艺、加热炉加热工艺以及轧制段横向冷却工艺等措施,板坯边裂缺陷率由原来的30%,降至5.1%,减少了切边量。对实际生产及质量异议钢板处理具有一定指导意义。

树干自流式注药法中影响药剂吸收因子研究

采用4%吡虫啉注干液剂,研究自流式注药过程中注药孔孔径、注药器通气孔孔径、树种、树干基径及季节等因素对药剂吸收的影响。结果表明:注药孔孔径及树种对药剂吸收影响较大,其次为树干基径和季节,注药器通气孔孔径对药剂吸收的影响不显著。5mm注药孔孔径下树体对药剂的吸收显著高于2,3mm注药孔,注药后10h树体对药剂的吸收一般可达6～8mL;两种通气孔孔径(0.5,1mm)下树体对药剂吸收的速度差异较小;9种树种对药剂的吸收能力依次为:毛白杨>白梨>李>侧柏>水杉>悬铃木、国槐、垂柳>合欢;树干基径对药剂吸收的影响因树种而异,国槐表现为基径较大的树体对药剂的吸收能力较强,侧柏与之相反,毛白杨不同基径树体对药剂吸收的差异不显著;5月份树体对药剂的吸收能力高于9月份。

钢件铸挂青铜结合面的气孔及防止途径

分析了柱塞泵转子钢坯上熔铸青铜的结合面(也称熔合面)出现气孔的各种可能原因或机理,针对这些气孔产生的原因或机理,提出了相应的防止途径或方法,并在铸造生产中保证此类零件铸挂结合面的质量方面取得了显著效果。

阀门堆焊产生气孔和裂纹原因的分析

通过测定阀门经加工后的残余应力、观察裂纹断口微观组织等，分析了阀门产生气孔和裂纹的原因，并提出改进阀门质量的实施方案。

超声波处理时间对铝合金铸锭内的气孔生成及细化的影响

研究了超声波处理时间对铝合金铸锭内气孔的影响,考察了超声波处理时间对铝合金铸锭组织细化的影响,分析了超声波处理时间对铝合金铸锭内气孔影响的原因。结果表明,当以适当的超声波处理时间施加时,可以得到良好的除气效果;处理时间过长,会导致气孔的增加。随着超声波处理时间的增加,铸锭细化率呈急剧增加的趋势,当增加到一定值后,细化率变化幅度变小。细化作用可以大幅度提高铸锭的致密度。