A novel box-counting method for quantitative fractal analysis of threedimensional pore characteristics in sandstone

Fractal theory offers a powerful tool for the precise description and quantification of the complex pore structures in reservoir rocks,crucial for understanding the storage and migration characteristics of media within these rocks.Faced with the challenge of calculating the three-dimensional fractal dimensions of rock porosity,this study proposes an innovative computational process that directly calculates the three-dimensional fractal dimensions from a geometric perspective.By employing a composite denoising approach that integrates Fourier transform(FT)and wavelet transform(WT),coupled with multimodal pore extraction techniques such as threshold segmentation,top-hat transformation,and membrane enhancement,we successfully crafted accurate digital rock models.The improved box-counting method was then applied to analyze the voxel data of these digital rocks,accurately calculating the fractal dimensions of the rock pore distribution.Further numerical simulations of permeability experiments were conducted to explore the physical correlations between the rock pore fractal dimensions,porosity,and absolute permeability.The results reveal that rocks with higher fractal dimensions exhibit more complex pore connectivity pathways and a wider,more uneven pore distribution,suggesting that the ideal rock samples should possess lower fractal dimensions and higher effective porosity rates to achieve optimal fluid transmission properties.The methodology and conclusions of this study provide new tools and insights for the quantitative analysis of complex pores in rocks and contribute to the exploration of the fractal transport properties of media within rocks.

Rectangular tunnel heading stability in three dimensions and its predictive machine learning models

Tunnel heading stability in two dimensions(2D)has been extensively investigated by numerous scholars in the past decade.One significant limitation of 2D analysis is the absence of actual tunnel geometry modeling with a considerable degree of idealization.Nevertheless,it is possible to study the stability of tunnels in three dimensions(3D)with a rectangular shape using finite element limit analysis(FELA)and a nonlinear programming technique.This paper employs 3D FELA to generate rigorous solutions for stability numbers,failure mechanisms,and safety factors for rectangular-shaped tunnels.To further explore the usefulness of the produced results,multivariate adaptive regression spline(MARS)is used for machine learning of big dataset and development of design equations for practical design applications.The study should be of great benefit to tunnel design practices using the developed equations provided in the paper.

SAR regional all-azimuth observation orbit design for target 3D reconstruction

Three-dimensional(3D) synthetic aperture radar(SAR)extends the conventional 2D images into 3D features by several acquisitions in different aspects. Compared with 3D techniques via multiple observations in elevation, e.g. SAR interferometry(InSAR) and SAR tomography(TomoSAR), holographic SAR can retrieve 3D structure by observations in azimuth. This paper focuses on designing a novel type of orbit to achieve SAR regional all-azimuth observation(AAO) for embedded targets detection and holographic 3D reconstruction. The ground tracks of the AAO orbit separate the earth surface into grids. Target in these grids can be accessed with an azimuth angle span of360°, which is similar to the flight path of airborne circular SAR(CSAR). Inspired from the successive coverage orbits of optical sensors, several optimizations are made in the proposed method to ensure favorable grazing angles, the performance of 3D reconstruction, and long-term supervision for SAR sensors. Simulation experiments show the regional AAO can be completed within five hours. In addition, a second AAO of the same area can be duplicated in two days. Finally, an airborne SAR data process result is presented to illustrate the significance of AAO in 3D reconstruction.

A combination of digital design and three-dimensional printing to assist treatment of thoracolumbar compression fractures using percutaneous kyphoplasty

Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tures.Methods:From January 2018 to August 2020,we obtained data of 99 patients diagnosed thoracolumbar compression fractures.These patients were divided into control group(n=50)underwent traditional PKP surgery,and observation group(n=49)underwent preoperative digital design combined with 3D printing model assisted PKP treatment.The clinical efficacy was evaluated with five parameters,including operation time,number of intraoperative radiographs,visual analogue scale(VAS)score,Cobb Angle change,and high compression rate of injured vertebrae.Results:There were statistically significant differences of operation time and number of intraoperative radio graphs between the two groups(P<0.05).For VAS score,Cobb Angle change and vertebral height compression rate,all of these three parameters were significantly improved when the patients accepted surgery teatment in two groups(P<0.05).However,there were no significant differences between control group and observation group for these three parameters either before or after surgery(P>0.05).Conclusions:Through the design of preoperative surgical guide plate and the application of 3D printing model to guide the operation,the precise design of preoperative surgical puncture site and puncture Angle of the injured vertebra was realized,the number of intraoperative radiographs was reduced,the operation time was shortened and the operation efficiency was improved.

Design and Application of Modern Interior Design Style System Based on Unity3D

With the constant change of fashion trends,interior design styles are changing day by day.Based on Unity3D technology,this paper develops a system for modern interior-style design and application.Taking the residential interior as a case study,the interior style design is achieved through 3D modeling and texture rendering and then combined with the Unity3D engine to achieve scene roaming and interactive design.The system enables designers to express design concepts more intuitively and efficiently and also improves customer participation and satisfaction.Through the experience of designers and customers,the system is verified to have more practical value than traditional interior design solutions.

Three-Dimensional Concurrent Design System for Walking-Beam Furnace

This paper focuses on the problem of low efficiency and limited non-geometric information handling ability in the process of 2D heating furnace design, proposes a 3D concurrent parametric design system, this method is realized by parametric design technology, which is supported by ActiveX-Automation technology and VBA technology, mutual visit between application programs makes batched modeling become possible, key dimensions are linked with each other by restrictions, so parts can be built concurrently by sharing few parameters between common borders, designer can be free from repeated drawing work during modification, Solid Edge is chosen as the modeling server, a secondary development software is programmed by Visual Basic, this system provides a feasible way to overlap time between different sections, the design efficiency and quality is improved significantly.

The Use of Three-Dimensional Integrated Design System in Smart Substation Design

The traditional power design, construction, has been able to meet the requirements, but it has not been established engineering data database support and the correlation between the data is poor, due to inadequate coordination among design professionals, design easily lead to mistakes, field problems, and design results failed in all aspects of the project to be fully utilized. With the technology of three-dimensional integrated design system penetrates in all walks of life, the introduction of three-dimensional integrated design system substation design solutions and the application of common devices of State Grid Corporation in recent years, which provide technical conditions for the application of virtual reality technology in substation design. According to its own characteristics of substation project, we now propose prospect on virtual reality technology in substation design application.

基于参数化设计的熔融挤压快速成型3D打印织物

针对3D打印织物表面存在单丝压缩性能差的问题,利用熔融挤压快速成型打印技术对织物表面进行设计应用。以常见的几何形体为基础元素,运用三维参数化方式处理织物表面形体结构,利用熔融挤压快速成型技术制备织物单丝,并设计三维立体织物表面形体参数;通过控制打印材料的挤出速度以匹配出丝速度与填充速度,实现织物表面立体设计;并与熔融层积成型技术、选择性激光烧结(SLS)2种3D打印技术进行对比分析。实验结果表明:经参数化设计后,熔融挤压快速成型3D打印技术显著提高了织物单丝的压缩性能,同时强化了织物表面质量,极大提高了3D打印织物的便利性。

Application and Implementation of Quest3D Technology in Garden Landscape Design

The application of virtual reality technology has become more and more influential in garden design. Quest3D as a significant software to realize the virtual reality technology is utilized in this study to make a garden roaming demonstration system with the gardening design of a classical courtyard as an example. Besides, the advantages and disadvantages of applying Quest3D technology in garden landscape design are elaborated from the perspective of the selection of Quest3D technology, basic procedures for the selection and establishment of software and hardware.

基于Design3D的汽轮机低压静叶三维气动优化设计

文章基于商业软件NuMECA的全三维优化设计平台Design3D,采用三维N-S方程流场计算、网格自动生成、三维叶片参数化造型与遗传算法寻优相结合的方法,在级环境下对600MW汽轮机静叶进行了三维叶片型线优化设计。优化目标是在流量基本不变的情况下尽可能地提高级轮周效率。优化设计后的叶片与原叶片相比,透平级的总-总效率提高了0.32%,级的轮周效率提高了0.39%。详细的流场分析表明,优化后叶片性能的提高主要是源于静叶总压损失的减小和透平级动静叶之间匹配的改善。

基于Geomagic Design X的产品建模研究与3D打印成型--以内燃机连杆为例

以工业产品设计为对象,采用某国产手持激光3D扫描仪获取模型点云数据,结合Geomagic Design X软件介绍逆向设计方法与工业产品逆向建模过程,采用3D打印技术进行快速制造完成产品验证。为产品建模优化与成型提供思路和方法,减少产品开发周期。实践证明采用Geomagic Design X软件可以快速高质量的完成产品模型的重构设计,3D打印可以实现模型的再现验证设计。

工科专业课堂“3D(Debate/Design/Doing）”教学法研究

基于当前高校工程教育专业认证的要求,论文首次提出了工科专业课堂“3D(Debate/Design/Doing)”教学法,其核心教学理念是“我思故我想,我想故我说,我说故我做,我做故我会”,即通过课堂辩论(Debate)、项目设计(Design)和项目实施(Do?ing),将教师的课堂讲授信息通过这个过程进行批判性思辨,将理论知识和实际效果联系起来。该研究通过在材料加工工程专业模块课程铸造工艺和造型材料的教学实践,取得了所有选课学生的认同,真正做到了让学习过程由被动变为主动、由无趣变成有趣、由枯燥变为生动,学生由自卑变自信,使院系专业课程课堂教学和工程训练平台实现了无缝联合,对于提高工科专业的课堂教学效果具有广泛的借鉴意义,为达到国际工程专业认证标准提供了很好的教学示范作用。

基于Design3D的汽轮机低压静叶三维气动优化设计

本文基于商业软件NUMECA的全三维优化设计平台Design3D，采用三维N-S方程流场计算、网格自动生成、三维叶片参数化造型与遗传算法寻优相结合的方法，在级环境下对600MW汽轮机静叶进行了三维叶片型线优化设计，优化目标是在流量基本不变的情况下尽可能的提高级轮周效率。优化设计后的叶片与原叶片相比，透平级的总一总效率提高了0．32％，级的轮周效率提高了O．39％。详细的流场分析表明，优化后叶片性能的提高主要是源于静叶总压损失的减小和透平级动静叶之间匹配的改善。

AutoCAD Civil 3D和3ds Max Design在道路建模中的应用

介绍利用AutoCAD Civil 3D进行道路建模的过程,并将Civil 3D道路模型导入到3ds Max Design中作进一步加工,从而进一步获取道路的三维景观模型。

Three-Dimensional Ocean Sensor Networks:A Survey

The past decade has seen a growing interest in ocean sensor networks because of their wide applications in marine research,oceanography,ocean monitoring,offshore exploration,and defense or homeland security.Ocean sensor networks are generally formed with various ocean sensors,autonomous underwater vehicles,surface stations,and research vessels.To make ocean sensor network applications viable,efficient communication among all devices and components is crucial.Due to the unique characteristics of underwater acoustic channels and the complex deployment environment in three dimensional(3D) ocean spaces,new efficient and reliable communication and networking protocols are needed in design of ocean sensor networks.In this paper,we aim to provide an overview of the most recent advances in network design principles for 3D ocean sensor networks,with focuses on deployment,localization,topology design,and position-based routing in 3D ocean spaces.

Pattern design on 3D triangular garment surfaces

This paper focuses on a pattern design method for a 3D triangular garment surface. Firstly, some definitions of 3D style lines are proposed for designing the boundaries of patterns as drawing straight lines or splines on the triangular surface. Additionally some commonly used style lines are automatically generated to enhance design efficiency. Secondly, after style lines are preprocessed, a searching method is presented for quickly obtaining the boundaries and patches of a pattern on the 3D trian- gular surface. Finally a new pattern design reuse method is introduced by encoding/decoding the style line information. After style lines are encoded, the pattern design information can be saved in a pattern template and when decoding this template on a new garment surface, it automates the pattern generation for made-to-measure apparel products.

3D deformation effect and optimal excavated design of surface mine

The three-dimensional （3D） deformation effect of the slope engineering under the step-by-step excavation for the Antaibao surface mine was analyzed using the FLAC^3D technique. An optimal excavated scheme with a relatively steeper slope angle of 47° instead of 30° was successfully implemented at the west wall in the geological section 73200 of the mine area, where the 3D effect of the nonlinear large deformation of the slope was taken into account. Based on the above research conclusion, put forward the countermeasures of shortening mining length, excavating by different regions, timely foot backfilling to protect the excavated slope, and monitoring and feedback adjustment by studying the nonlinear effect. The results show that these countermeasures are effective in controlling maximum deformation and increasing the stability of the slope.

Surface characteristics analysis of fractures induced by supercritical CO_(2)and water through three-dimensional scanning and scanning electron micrography

Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.

Collaborative Design in PDM / 3D CAD Integrated Environment

Some key issues in supporting collaborative design in product data management（PDM ） system and 3D computer aided design（CAD） system integrated environment are analyzed. The general architecture of the integrated environment is divided into five tiers and employs the transparently integrated mode, with the mode, function calling and information exchanging among independent PDM and CAD processes are carried out via message translation /parse approach. Product layout feature（PLF ） model definition is presented, PLF model is used to represent design intention at the preliminary design phase. The collaborative design methodology employing the PLF model in PDM/3D CAD integrated environment is analyzed. The design methodology can speed up the design process, reduce the investment and improve the product quality.

Review on Applications of 3D Inverse Design Method for Pump

The 3D inverse design method, which methodology is far superior to the conventional design method that based on geometrical description, is gradually applied in pump blade design. However, no complete description about the method is outlined. Also, there are no general rules available to set the two important input parameters, blade loading distribution and stacking condition. In this sense, the basic theory and the mechanism why the design method can suppress the formation of secondary flow are summarized. And also, several typical pump design cases with different specific speeds ranging from centrifugal pump to axial pump are surveyed. The results indicates that, for centrifugal pump and mixed pump or turbine, the ratio of blade loading on the hub to that on the shroud is more than unit in the fore part of the blade, whereas in the aft part, the ratio is decreased to satisfy the same wrap angle for hub and shroud. And the choice of blade loading type depends on the balancing of efficiency and cavitation. If the cavitation is more weighted, the better choice is aft-loaded, otherwise, the fore-loaded or mid-loaded is preferable to improve the efficiency. The stacking condition, which is an auxiliary to suppress the secondary flow, can have great effect on the jet-wake outflow and the operation range for pump. Ultimately, how to link the design method to modem optimization techniques is illustrated. With the know-how design methodology and the know-how systematic optimization approach, the application of optimization design is promising for engineering. This paper summarizes the 3D inverse design method systematically.