Anisotropic creep behavior of soft-hard interbedded rock masses based on 3D printing and digital imaging correlation technology

Three-dimensional(3D)printing technology is increasingly used in experimental research of geotechnical engineering.Compared to other materials,3D layer-by-layer printing specimens are extremely similar to the inherent properties of natural layered rock masses.In this paper,soft-hard interbedded rock masses with different dip angles were prepared based on 3D printing(3DP)sand core technology.Uniaxial compression creep tests were conducted to investigate its anisotropic creep behavior based on digital imaging correlation(DIC)technology.The results show that the anisotropic creep behavior of the 3DP soft-hard interbedded rock mass is mainly affected by the dip angles of the weak interlayer when the stress is at low levels.As the stress level increases,the effect of creep stress on its creep anisotropy increases significantly,and the dip angle is no longer the main factor.The minimum value of the long-term strength and creep failure strength always appears in the weak interlayer within 30°–60°,which explains why the failure of the layered rock mass is controlled by the weak interlayer and generally emerges at 45°.The tests results are verified by comparing with theoretical and other published studies.The feasibility of the 3DP soft-hard interbedded rock mass provides broad prospects and application values for 3DP technology in future experimental research.

Teaching Reform of Building Construction Course under the Background of New Digital Technology

With the advent of the information age,all walks of life have paid more and more attention to the development and application of digital technology.At the same time,the construction industry,which is a traditionally important industry,is not an exception.A series of high-tech digital technologies have been widely used in architectural design and construction,such as BIM technology,3D printing technology,and VR technology.In view of the teaching link of architectural talent training,it is necessary to keep up with the development trend of the digital age,integrate these three kinds of technology into architectural teaching,and impart knowledge to students from planar 2D textbooks to 3D visual digital models,and further transform it from 3D digital to physical perceive or virtual simulation level,and reform teaching methods in all dimensions and in all dimensions to improve teaching effect.In this paper,the feasibility and necessity of integration of the above three architectural digital techniques into the teaching process of"building construction"from the aspects of teaching content,teaching method and teaching evaluation were discussed,and a new teaching model under the background of digital technology was proposed,which has certain teaching reference significance.

Development and prospects of digital orthopedics in Hubei province

Based on the development and application of new technology,as a new interdisciplinary subject,digital orthopedics becomes an important development direction of modern medicine in the past years.Using digital orthopedics technology,such as 3D digital printing technology,mixed reality technology,provides new impetus of orthopedic surgery and indicates its great potential of precision medicine and personalized therapy for orthopedic disorders.In 2017,Hubei Branch of China Digital Orthopaedic Society of SociétéInternationale de Chirurgie Orthopédique et de Traumatologie(SICOT)was founded.It is an important milestone and academic event for the development of digital orthopedics in Hubei.After that,Hubei's digital orthopedics professionals have made great progress in clinical,scientific research,conference and social activities.The development of 5G technologies in China will provide more opportunities and challenges for global digital orthopedics in the near future.

Accuracy of Orthodontic 3D Printed Retainers versus Thermoformed Retainers

Background: The integration of the current technology of CBCT and 3D CAD/CAM technology has great potential in the field of orthodontics, which is not yet fully investigated. The purpose of this article is to evaluate the accuracy of 3D printed retainers in comparison to vacuum formed retainers. Methods: Alginate impressions were taken for ten patients who have a CBCT scan. A 3D printed retainer and vacuum formed retainer were fabricated. Linear measure-ments were measured by two assessors using digital caliper. Every measure-ment on the 3D printed retainer was compared to the corresponding measure-ment on the thermoformed retainer. The linear measurements were Inter-canine width, Inter-premolar width (first and second premolars), Inter-molar width, Canine-midline length (both sides) and Canine-molar length (both sides). Intra-observer, and inter-observer reliability measurements were done. Results: Results showed excellent intra-observer reliability for the thermoformed retainer and the 3D printed retainer. Inter-observer measurements showed strong agreement between the measurements of the two assessors, for both retainers. The comparison of the thermoformed retainer to the 3D printed retainer showed high statistical agreement, except for the canine-molar on the right side, but with no clinical significance, p value of 0.038 and mean difference 0.19. Conclusions: The new method for fabricating a 3D printed retainer is accurate and reliable in comparison to the vacuum formed retainer (conventional method). CBCT proved to be efficient for fabrication of a custom made appliances.

3D数字打印导航模板技术在青少年脊柱侧弯手术中的应用

目的 探讨3D数字打印导航模板技术在青少年脊柱侧弯手术中的应用效果。方法 选取2021年1月至2023年1月郑州市骨科医院收治的72例青少年脊柱侧弯患者为研究对象。按照随机数字表法分为对照组与观察组,每组36例。对照组以常规手段进行椎弓根螺钉固定矫形术治疗,观察组以3D数字打印导航模板技术辅助椎弓根螺钉固定矫形术。对比两组手术情况、并发症发生率、术中置钉有效率、脊柱活动度等。结果 观察组手术时间、术中出血量、术中透视次数、术后住院时间均小于对照组(P<0.05)。观察组并发症发生率(5.56%,2/36)低于对照组(22.22%,8/36),差异有统计学意义(χ^(2)=4.181,P=0.041<0.05)。治疗后,观察组置钉有效率(91.67%,33/36)高于对照组(72.22%,26/36),差异有统计学意义(χ^(2)=4.600,P=0.032<0.05)。术前,两组脊柱活动度比较差异未见统计学意义(P>0.05);术后3个月,两组脊柱活动度均高于术前,且观察组脊柱活动度均高于对照组,差异均有统计学意义(P均<0.05)。结论 3D数字打印导航模板技术在青少年脊柱侧弯手术中应用效果良好,能够减少患者术后出血量,缩短手术时间,提高螺钉置钉准确率,降低术后并发症发生率,提高患者术后脊柱活动度。

Exploring innovative techniques for damage control during natural disasters

The study critically examines the principles,mechanisms,and effectiveness of different damage control tech-niques in dealing with natural disasters,emphasizing their pivotal role in minimizing casualties and economic losses.Each of these damage control techniques is mapped based on their applications and relevance in the key areas of natural disaster management.By utilizing various real-world instances,the present study shows that the effective implementation of various innovative techniques is shaping the space of natural disaster management in a global context.The integration of different innovative techniques into the existing natural disaster management system has improved the survival rate,economic performance,and sustainable development.The study finds that innovative disaster financing models,clear strategies,and creating awareness among communities can improve the overall efficiency of innovative techniques that are currently used for damage control during natural disaster events.Despite the substantial advantages of these creative strategies,the study acknowledges challenges such as financial constraints,unclear policy goals,and community adaptation requirements.The study also indicates that in the future,automatic damage restoration,quick prototyping,and additive engineering will play a vital role in controlling damage from catastrophic events,while it acknowledges limitations in temporal scope,generaliz-ability,andfinancial constraints.

数字化快速成型技术在全膝关节置换术中应用

目的探究数字化快速成型技术在全膝关节置换术(TKA)中应用的可行性及临床疗效。方法选择1例需行TKA的骨性关节炎患者,通过三维重建得到患者膝关节的DICOM格式数据;借助于医学影像控制系统Mimics 15.0和三维工程设计软件Unigraphics NX 9.0进行计算分析、图像处理等操作,建立与患者股骨髁和胫骨平台三维互补的膝关节截骨导向板的数字模型;然后,依靠快速成型技术打印制作的截骨导向板实物模型,通过截骨导航模板与膝关节紧密贴合,按照预先设计的截骨通道进行膝关节截骨。结果患者截骨操作顺利,TKA手术时间115 min,术中出血约450 ml;术后X线影像显示,膝关节假体在位正常,关节间隙变宽,膝关节外翻畸形完全矫正;术后2周膝关节HSS功能评分为89.6。结论数字化快速成型技术在TKA的个体治疗中,具有快速性、个体化、精确性高及损伤小等优点,临床疗效确切。