Wetting front migration model of ion-adsorption rare earth during the multi-hole unsaturated liquid injection

In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distance of wetting fronts are still unclear.Besides,wetting front migration distance and leaching time are usually required to optimize the leaching process.In this study,wetting front migration tests of ionadsorption rare earth ores during the multi-hole fluid injection(the spacing between injection holes was 10 cm,12 cm and 14 cm)and single-hole fluid injection were completed under the constant water head height.At the pre-intersection stage,the wetting front migration laws of ion-adsorption rare earth ores during the multi-hole fluid injection and single-hole fluid injection were identical.At the postintersection stage,the intersection accelerated the wetting front migration.By using the Darcy’s law,the intersection effect of wetting fronts during the multi-hole liquid injection was transformed into the water head height directly above the intersection.Finally,based on the Green-Ampt model,a wetting front migration model of ion-adsorption rare earth ores during the multi-hole unsaturated liquid injection was established.Error analysis results showed that the proposed model can accurately simulate the infiltration process under experimental conditions.The research results enrich the infiltration law and theory of ion-adsorption rare earth ores during the multi-hole liquid injection,and this study provides a scientific basis for optimizing the liquid injection well pattern parameters of ion-adsorption rare earth in situ leaching in the future.

Experimental investigation of key parameters pertinent to multi-hole orifice throttling characteristic

This study firstly defines a set of arrangement rule for perforated holes of multi-hole orifice(MO), and then presents three critical geometrical parameters including total number of performated hole, equivalent diameter ratio and distribution density of perforated holes, which are to quantify MO structure. This paper built the throttling test apparatus for nice test MO plates, which were designed according to orthogonal theory. The experiments were conducted to investigate the effect of three critical geometerical parameters on the pressure loss coefficient of test MOs. Results show that equivalent diameter ratio is the dominant prameter affecting MO throttling characterstic.

Influence of the Hole Chamfer on the Characteristics of a Multi-hole Orifice Flowmeter

In order to analyze the influence of the hole chamfer on the metering performances of a Multi-hole Orifice Flowmeter and optimize the related orifice structure,a multi-hole orifice flowmeter with DN80 and throttle ratio of 0.45 was considered in the present study.The flow field characteristics were determined in the framework of a CFD technique.The results show that the multi-hole orifice flowmeter with filleting transition around the throttle orifice has higher accuracy in a wide range of the space of parameters,and is more suitable for accurate measurement of fluid in process control.

Multi-hole joint acquisition of a 3D-RVSP in a karst area:Case study in the Wulunshan Coal Field,China

Conventional surface seismic exploration in areas with complex surfaces such as karst landforms has been faced with the problem of poor excitation and reception conditions.RVSP(reverse vertical seismic profile)seismic exploration adopts a geometry in which the sources are downhole and receivers are on the ground which can reduce the influence of complex surfaces on seismic wave propagation(to some extent).Through numerical simulations and real data analysis,it was noted that in areas with complex surfaces and large numbers of underground karst caves,seismic waves generated in shallow boreholes are easily affected by various surface and multiple waves as well as by scattering from karst bodies.Therefore,the quality of the reflected seismic data is extremely low.Also,it is difficult to improve the signal to noise ratio(SNR)with conventional noise filtering methods.However,when the source depth is increased,the quality of the reflected waves can be improved.This is exactly what the RVSP method accomplishes.Besides,for the RVSP method,due to its particular geometry,the apparent velocities of the reflected waves and most interference waves are quite different,which can help to filter most noise to further improve the SNR of the reflected signals.In this study,a 3 D-RVSP exploration study using 8-hole joint acquisition was conducted in a typical karst landform.The results show that the 3 D-RVSP method can obtain higher quality seismic data for complex surface conditions that have large numbers of underground karst caves.Furthermore,multi-hole joint acquisition for 3 D-RVSP has higher data collection efficiency and better uniformity of underground coverage.Therefore,in this study,38 faults were accurately revealed and at high resolution based on the 3 D-RVSP imaging results.

Development of a biliary multi-hole self-expandable metallic stent for bile tract diseases: A case report

BACKGROUND Uncovered stents used for malignant obstructions in the biliary tree, especially in the hilar area, are prone to obstruction by tumor ingrowths. In comparison, however, covered stents may block bile duct branches and are at risk of migration. We have developed a multi-hole self-expandable metallic stent (MHSEMS), with a hole in each cell, to prevent the obstruction of bile duct branches. In addition, the holes may prevent migration due to small ingrowths by reducing the tension of the membrane. CASE SUMMARY MHSEMS were placed in five patients with a malignant obstruction and one with post-endoscopic sphincterotomy bleeding. Each MHSEMS was successfully deployed in all cases. Patients showed no complications. Two cases were reviewed. Case 1: A 74-year-old male presented with jaundice and was diagnosed with a sigmoid colon cancer and giant liver metastases in the right liver lobe. A MHSEMS was placed in the left bile duct. The jaundice improved and peroral cholangioscopy was performed. Case 2: A 90-year-old female was admitted to hospital for jaundice and diagnosed with cholangiocarcinoma. A MHSEMS was placed in the left bile duct but after 8 months the stent became obstructed by tumor ingrowth. We treated the patient by ablation therapy. A silicone cover separated the internal bile duct from the surrounding tissue, protecting the latter from thermal injury during treatment by endobiliary ablation of the reobstruction. CONCLUSION A MHSEMS is a new choice of stent for biliary tract diseases.

Single-mode low threshold current multi-hole vertical-cavity surface-emitting lasers

A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of an oxidation- confined 850 nm VCSEL. The single-mode output power of 2.6 mW, threshold current of 0.6 mA, full width of half maximum lasing spectrum of less than 0.1 nm, side mode suppression ratio of 28.4 dB, and far-field divergence angle of about 10% are obtained. The effects of different hole depths on the optical characteristics are simulated and analysed, including far-field divergence, spectrum and lateral cavity mode. The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter hole spacing and the scattering loss at the bottom of the holes, particularly for higher order modes.

A new analytical-numerical method for calculating interacting stresses of a multi-hole problem under both remote and arbitrary surface stresses

Based on the elementary solutions and new integral equations,a new analytical-numerical method is proposed to calculate the interacting stresses of multiple circular holes in an infinite elastic plate under both remote stresses and arbitrarily distributed stresses applied to the circular boundaries.The validity of this new analytical-numerical method is verified by the analytical solution of the bi-harmonic stress function method,the numerical solution of the finite element method,and the analytical-numerical solutions of the series expansion and Laurent series methods.Some numerical examples are presented to investigate the effects of the hole geometry parameters(radii and relative positions)and loading conditions(remote stresses and surface stresses)on the interacting tangential stresses and interacting stress concentration factors(SCFs).The results show that whether the interference effect is shielding(k<1)or amplifying(k>1)depends on the relative orientation of holes(α)and remote stresses(σ^∞x,σ^∞y).When the maximum principal stress is aligned with the connecting line of two-hole centers andσ^∞y<0.5σ^∞x,the plate containing two circular holes has greater stability than that containing one circular hole,and the smaller circular hole has greater stability than the bigger one.This new method not only has a simple formulation and high accuracy,but also has an advantage of wide applications over common analytical methods and analytical-numerical methods in calculating the interacting stresses of a multi-hole problem under both remote and arbitrary surface stresses.

Experimental study of a simple pressure loss coefficient model for multi-hole orifice

A throttling experiment for the multi-hole orifice （MO） using water was conducted based on the conclusion of key parameters affecting the MO throttling performance. Testing MOs and standard orifice plates （ SO ） were designed for the throttling experiment to compare the throttling effect using the equivalent diameter ratio （RED） and diameter ratio （RD ） as key parameters, respectively. Meanwhile, effective metrical conditions were provided for experimental accuracy. The throttling model form was determined according to the theoretical throttling model of SO. Then the unknown parameters involved were identified by experimental data. A good concordance between the modeling computation and experimental results shows a validation of the MO throtting model.

Optimization Design of Multi-hole and Varied Diameter Pipe Based on RAGA

Combining real accelerating genetic algorithm(RAGA) with the optimization design of multi-hole and varied diameter pipe, the authors solved the problem of optimizing multi-dimensional parameters at the same time. In which the advanced convergence and easily to run into partial optimization were avoid. Applied the RAGA to solving the problem in the optimization design of fixed piping sprinkler irrigation system. The optimized parameters, such as diameters and the length of pipe were calculated and the result was reasonable, which provides as a reference to readers who work at related research.

Stability Analysis of a Multi-holes Shell Under Axial Compression

The paper presents a multi-holes shell with one hundred and eighty circular holes which has been used in engineering. Using a buckling module of the finite element analysis software, stability behavior and destroy mode along geometry parameters are studied. Results show the destroy mode depends on the geometry parameter greatly. Curves of buckling critical load and strength limited load along geometry parameters have a point of intersection. The point implies the multi-holes shell has different destroy mode and the value of point is change in geometry parameters.

Boosting multi-hole water oxidation catalysis on hematite photoanodes under low bias

The accumulation of multiple surface holes is considered to be the key to efficient photoelectrochemical(PEC)water oxidation.Previous PEC water oxidation studies commonly apply high potentials(>1.2 VRHE)to achieve this key.But how to complete multi-hole transfer under low bias(<1.2 VRHE)remains unknown.Herein,we find that,on a typical visible-light photoanode,hematite(α-Fe_(2)O_(3)),UV excitation plays a indispensable role in driving multi-hole water oxidation under low bias.Compared with the visible-light excitation,the UV excitation promotes the formation of adjacent surface-trapped holes onα-Fe_(2)O_(3) at 0.9VRHE,thereby increasing the reaction order of surface holes from~1 to~2 and improving the PEC water oxidation activity by one order of magnitude.The UV irradiation reduces the formation probability of self-trapped excitons and results in~3 to 5-fold increase of surface holes.These advantages enable the UV excitation to contribute about 40%to the total photocurrent under 1 solar illumination,even though its energy only occupies 6%of the incident light.This mechanism is also applicable to boost selective two-hole oxidation of thioether at 0.1 VFc/Fc+and nitrite at 0.9 VRHE.

Influence of Multi-hole Arrangement on Cooling Film Development

A series of computations is conducted for many multi-hole arrangements at several blowing ratios to further investigate the evolution of the film from multi-holes. The influence of multi-hole arrangement on effusion film cooling is analyzed and a preliminary relationship evaluating the film development from developing state to developed state is brought forward. Results show that the coolant jets from front rows of multi-holes merge rapidly and the strength of the kidney vortices due to mainstream-coolant jet interaction in the downstream region are mitigated under super-long-diamond arrangement where the streamwise hole-to-hole pitch is bigger than spanwise hole-to-hole pitch. The holes array arranged in super-long-diamond mode is not only in favor of obtaining developed film layer, but also improving averaged adiabatic film cooling effectiveness.

Research on error compensation of robot based on multi-hole measurement technology and particle swarm optimization

Robot error compensation is a technique for enhancing the positioning accuracy of the system. This paper presented an error measuring technique for serial robots based on the multi-hole measuring method, combined with the intelligent particle swarm optimisation(PSO) to obtain the optimal solution of the robot’s error compensation values, thereby improving the positioning accuracy of the robot. In the experiment, the robot error was measured using self-made multi-hole measuring plates and probes, and the experimental data were combined with PSO for the error comprehensive analysis. The results showed that on this type of serial robot, the multi-hole measuring method and PSO algorithm had obvious error compensation effects, which effectively improved the positioning accuracy of the robot, with the error reduced by 35% after compensation.

A novel method for simulating nuclear explosion with chemical explosion to form an approximate plane wave: Field test and numerical simulation

A nuclear explosion in the rock mass medium can produce strong shock waves,seismic shocks,and other destructive effects,which can cause extreme damage to the underground protection infrastructures.With the increase in nuclear explosion power,underground protection engineering enabled by explosion-proof impact theory and technology ushered in a new challenge.This paper proposes to simulate nuclear explosion tests with on-site chemical explosion tests in the form of multi-hole explosions.First,the mechanism of using multi-hole simultaneous blasting to simulate a nuclear explosion to generate approximate plane waves was analyzed.The plane pressure curve at the vault of the underground protective tunnel under the action of the multi-hole simultaneous blasting was then obtained using the impact test in the rock mass at the site.According to the peak pressure at the vault plane,it was divided into three regions:the stress superposition region,the superposition region after surface reflection,and the approximate plane stress wave zone.A numerical simulation approach was developed using PFC and FLAC to study the peak particle velocity in the surrounding rock of the underground protective cave under the action of multi-hole blasting.The time-history curves of pressure and peak pressure partition obtained by the on-site multi-hole simultaneous blasting test and numerical simulation were compared and analyzed,to verify the correctness and rationality of the formation of an approximate plane wave in the simulated nuclear explosion.This comparison and analysis also provided a theoretical foundation and some research ideas for the ensuing study on the impact of a nuclear explosion.

加强筋位置对半穿甲战斗部侵彻多层钢靶性能影响研究

为了研究加强筋位置对半穿甲战斗部侵彻多层钢靶性能的影响,通过试验及数值仿真,研究了加强筋在弹体轴向不同位置处的2种半穿甲战斗部,以一定速度(710 m/s)、着角(20°)侵彻8层钢靶的弹道偏转、弹孔尺寸、余速的差异。研究结果表明:加强筋位置由弹尖向质心位置逼近时弹道偏转角减小、弹孔长轴减小、穿甲能力提升;弹道偏转角增量与靶间距呈正相关关系;弹道偏转角、侵彻余速、弹头侵蚀量及弹孔仿真结果与试验实测值最大偏差为8.82%,仿真与试验结果符合较好。研究结果可为半穿甲战斗部方案设计提供参考。

环形多孔气体静压止推轴承静态性能研究

为提升气体静压止推轴承的静态性能,设计一种新型环形多孔气体静压止推轴承。依据气体润滑原理、采用有限体积法对环形多孔气体静压止推轴承的三维物理模型进行数值模拟,研究节流器上节流孔数量、直径、分布方式和供气压力对气体静压止推轴承静态性能的影响。结果表明:节流孔数量对环形气体静压止推轴承的承载力影响显著,但孔数增加到一定程度后承载力增速放缓;节流孔直径对承载刚度影响较大,随着节流孔直径逐渐减小最佳刚度逐渐增大;节流孔排布方式和供气压力对气体静压止推轴承的静态性能均有明显影响。

粤港澳大湾区防风暴潮生态海堤核心技术研究及应用

在大湾区灵山岛北岸防风暴潮生态海堤工程的设计中,为解决城市防洪潮和滨海景观生态海堤亲水性的矛盾,在技术理念上由传统单一的防潮海堤向多元化滨海景观生态海堤转变,创新提出了多级消浪平台技术和滨海景观带迎水面系统排水技术来解决消浪与排水的问题,在实践中提出“横向换纵向”“外水外排,内水内排”的理念,打破传统海堤对海浪的“挡”和“抗”硬对硬模式,采用横向多级消浪平台技术消减越浪,并设置多级排水系统实现越浪自排,对迎水面海浪采用“通”和“排”的柔性衔接,可有效降低纵向堤顶高程以破解“堤防围城”的难题,实现海堤成为滨海生态景观的目的。研究成果已应用在该项目中,经过数次风暴潮检验证明达到了预期效果,灵山岛在韧性城市方面尤其是生态堤设计上,以宽度换高度,既能防洪同时又满足亲水、休闲、景观要求,为岭南地区的生态建设乃至中国滨海河口地区同类型建设提供了经验和参考。

梯形内嵌多方孔模块发射药的打印制备及定容燃烧性能

为了设计和制备弧厚小、燃烧时间短、渐增性好的新型发射药,以12.7 mm枪弹装药为对象,设计了梯形内嵌多方孔结构,采用直写成型工艺制备了外层弧厚不同、内嵌多方孔结构的梯形模块发射药。发射药长41 mm,内嵌方孔单边长为0.4 mm,内孔个数为3105。通过密闭爆发器试验,研究了模块发射药和制式药/模块发射药混合装药的定容燃烧性能。结果表明:打印发射药燃烧正常,在相对压力B>0.2后,外层弧厚为1.0 mm的模块发射药的动态燃烧活度相对外层弧厚为0.5 mm的下降较缓;当混合装药质量比为55时,分裂点后移,燃烧渐增性较好;打印发射药在爆发器内燃烧时间小于8 ms,与制式药燃烧时间相当,能满足小口径武器快速燃烧的要求。

基于改进MFO优化空间谱的埋地管道泄漏定位

现有管道泄漏声波定位法仅能提供泄漏所在区域。为实现区域内地下泄漏源的精确定位,基于地面均匀圆形阵列(uniform circular array, UCA),提出选择性反向学习飞蛾火焰优化(selective ppposition based moth-flame optimization, SOMFO)结合双波谱的埋地管道泄漏定位方法。针对土壤P1波和S波共存且波速不明确等问题,构造地面UCA的双波谱函数,以其最大输出为优化目标,使用SOMFO寻优双波速度及泄漏源三维坐标共5个参数,并设计了多孔泄漏定位策略。搭建了埋地管道泄漏试验装置,通过互谱解卷绕相位的直线特性验证了P1波和S波的存在。试验结果表明,基于SOMFO优化双波谱的定位方法可准确估计波速及三维坐标,定位误差最大为0.066 m。此外,研究了多孔泄漏及寻优算法对定位精度的影响。与现有两种精确定位方法相比,新方法对单孔泄漏的定位精度分别提升9.68%和24.32%,多孔泄漏分别提升49.17%和61.15%。

低透气性煤层多孔同步分段水力压裂增透技术研究

为了提高煤层透气性的增透效率,研究了煤层多孔同步分段水力压裂增透技术,介绍了多孔同步分段水力压裂技术的基本原理,通过实验室测试了高压封孔胶囊的耐压强度及多孔同步分段水力压裂系统的自动控制工艺,结果表明:高压封孔胶囊的最小破坏强度为35 MPa,多孔同步分段水力压裂可通过自动控制系统实时监测每个钻孔的压力数据,实现压裂过程的自动控制。同时在三元煤矿进行了现场工业试验,工业试验表明,3#煤层的起裂压力为23.3~25.4 MPa,当压裂距离为10 m时,压裂孔的裂纹扩展时间为26~38 min,裂纹沟通时间为28~40 min,可有效提高压裂效率。经过多孔同步分段水力压裂增透的煤层,相对于未压裂煤层,在30 d的统计时间内,压裂后的平均瓦斯浓度是未压裂的1.12倍,平均混合流量是未压裂的2.17倍,平均瓦斯纯量是未压裂的2.44倍,能够有效的增加煤层透气性,提高瓦斯抽采效果。