Visualized experimental investigation on the hydraulic characteristics of two-phase flow in a single smooth and single rough rock fractures

Chen Wang,Yujing Jiang,Jiankang Liu,Changsheng Wang,Satoshi Sugimoto 한국지질과학협의회 2021 Geosciences Journal Vol.25 No.3

In present engineering applications, calculations of hydraulic properties in two-phase flow are still highly dependent on empirical or semi-empirical equations obtained from experiments. However, the empirical equations that can reproduce the experiment data on a certain fracture specimen may have errors on other specimens. Researchers have obtained results that show quite different evolution forms of hydraulic characteristics of two-phase flow, which is induced by the variety of the influencing factors in two-phase flow. This paper aims at expanding the experimental results on the hydraulic characteristics of two-phase flow in rock fractures. With a newly developed experiment system, visualized two-phase flow experiments were introduced. The difference in the surface morphology of the fractures leads to totally different flow structures, which indicates the role of capillary pressure differs due to different fracture surfaces. The relative permeability in the rough specimen approximately follows the Corey model, which confirmed that the pressure drop is in this rough fracture is dominated by the capillary pressure, but the relative permeability is not only the function of saturation, but also the function of water flow velocities. However, the relative permeability is not perfect for evaluating the difference of two-phase hydraulic characteristics induced by the fracture surface morphology. On the contrary, the Lockhart-Martinelli model is appropriate for evaluating the difference in the two-phase hydraulic characteristics between the smooth fracture and the rough fracture, which indicates that the two-phase flow turbulence is obviously increased by the fracture roughness.

Periosteum-inspired in situ CaP generated nanocomposite hydrogels with strong bone adhesion and superior stretchability for accelerated distraction osteogenesis

Lou Tengfei,Chen Kai,Luo Qiyu,Liu Changsheng,Yuan Yuan,Fan Cunyi 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Distraction osteogenesis (DO) is an efficacious but lengthy procedure to reconstruct segmental bone defects under the principle of tension-stress, during which the periosteum-mediated mechanical stimulation plays a pivotal role. Inspired by the dynamic process of DO and the mechanical stimulation of periosteum, a new design of bionic periosteum was developed to simulate the mechanical transduction of natural periosteum for the application in DO procedure.In this study, an injectable organic-inorganic hybrid hydrogel was developed based on a novel combination of the PEGylated poly (glycerol sebacate) (PEGS) polymer network and in situ formed CaP nanoparticles (ICPNs). Rat bone marrow mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs) were cultured and tested in vitro to evaluate biocompatibility, cell adhesion, proliferation, and pro-osteogenic and pro-angiogenic activity. In vivo experiments were conducted in the rat tibial model of distraction osteogenesis.The developed nanocomposite hydrogels exhibited excellent injectability, robust bone adhesion, superior stretchability, and enhanced osteogenic activity. The results of in vitro and in vivo studies showed that PEGS/ICPN hydrogels could promote new bone formation and mineralization during the dynamic distraction process through the synergistic effects of angiogenesis and osteogenesis.This periosteum-inspired nanocomposite hydrogel represents a mechanobiology approach for effectively restoring large bone defects through the dynamic DO process.

Characterization of Hot Deformation Behavior and Processing Map of As‑Cast H13 Hot Work Die Steel

Yahui Han,Changsheng Li,Jinyi Ren,Chunlin Qiu,En LI,Shuaishuai Chen 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

The hot-working behavior of as-cast H13 hot work die steel was investigated in the method of isothermal compression testinvolving the wide deformation temperatures of 900–1150 °C and strain rates of 0.01–10 s−1, with the true strain to 0.8, onthe MMS-200 thermo-mechanical simulator. Two characteristic parameters involving the critical strain for DRX initiation(c ) and the strain for peak stress (p ) were identified. The ratio of critical strain to peak strain ranged from 0.26 to 0.6, whichdecreased with the increase in temperature and decrease in strain rate. Processing maps were established using dynamicmaterial model at strains of 0.2, 0.4, 0.6, 0.8. The power dissipation maps were not significantly affected by the strain, whilethe instability maps were sensitivity with the strain when it was over 0.4. The area of instability domain at strain of 0.8 wasthe largest. The instable characteristics contained the mixed grain structure, adiabatic shear band, intense deformation inserious deformation area and brittle elemental segregation area. The chief effect on the power dissipation was the strain rate,the optimum hot working parameters at strain of 0.8 (910–985 °C, 1010–1150 °C and 0.01–0.05 s−1) were determined. Inthis filed, the original coarse as-cast grains were gradually refined by dynamic recrystallization mechanism and the DRXgrain numbers had a significant increase with the increase of power dissipation efficiency.

Effect of Homogenisation Temperature on the Microstructure and Microhardness of As-Cast H13 Steel

Yahui Han,Changsheng Li,Shuai He,Cairu Gao,Shuaishuai Chen,En Li 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.3

This study determined that the homogenisation temperature range of experimental as-cast H13 steel was from 1150 to1230 °C, whilst the effect of homogenisation temperature range on the microstructural evolution and microhardness wastested. The enrichment of alloying elements in the dendrite segregation region decreased the solidus temperature of matrix,whose total content determined the maximum homogenisation temperature. The secondary dendrite branches were mostdissolved at 1150 °C, and overheating appeared at 1230 °C in the segregation region. Moreover, the primary carbidesunderwent shrinking, passivation, fragmentation and dissolution. The secondary carbides M23C6and M6Cwere formed atthe interfaces of MC/γ and M7C3/γ, respectively. As the homogenisation temperature increased from 1150 to 1230 °C, thevalue of microhardness gradually decreased from 771 to 740 HV. Nevertheless, the standard deviation value decreased firstand then increased, which reached the minimum 32 HV at 1200 °C, indicating that the hardness homogeneity was the best.

Collaborative optimization of NURBS curve cross-section in a telescopic boom

Aimin Ji,Changsheng Chen,Liping Peng,Pin Lv,Xiaodi He 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

To improve the carrying capacity and reduce the weight of telescopic boom structure in a truck crane, a Collaborative optimization (CO) approach was applied to solve the problems of strength, stiffness and local stability in the telescopic boom structure. First, the complex optimization problem of the telescopic boom structure was decomposed into two-level optimizations: the system level and two subsystem levels for strength and local stability. Second, the underside curve of the boom’s cross-section was constructed by the Nonuniform rational B-Splines (NURBS) curve. 3D parametric solid model and the parametric finite element analysis model for the strength and the local stability were then established. Third, the mathematical models of the strength and local stability for the subsystem levels, and the system level were optimized, respectively. The adaptive relaxation factor algorithm and the penalty function approach were applied to improve the efficiency of CO. Next, the CO process which integrates the ANSYS package with ISIGHT platform was implemented. The optimal results show that the carrying capacity of the telescopic boom structure can be significantly improved and its weight efficiently is reduced. Finally, with the comparison of the stress values obtained from both the experimental test and the theoretical computation, highly coincident results could be obtained to verify the reliability of CO of a telescopic boom.

Experimental study on the controlled air oxidation of sawdust in a packed-bed reactor

Meng Qingmin,Chen Xiaoping,Bu Changsheng,Ma Jiliang 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.4

The controlled air oxidation technology is a promising way of disposing medical waste, which has been a huge challenge in China. It converts waste through partial oxidation into a gaseous mixture, small quantities of char and condensable compounds. But operational performance of the primary chamber of the controlled air incinerator is poorly understood, leading to difficulty in control. In this paper, a packed-bed reactor was established to study the effect of O2 concentration on sawdust oxidation. The feed gas flow rate was kept constant at 0.6 m3/h at room temperature (26 oC) with O2 concentrations varied from 6% to 12%. Temperature profiles of the beds, product yields and gas compositions in the out-of-bed fuel gas were measured in detail. The results showed that the sawdust beds achieved low temperatures for the given O2 concentrations and leveled off in the oxidation processes. The bed temperatures increased and the solid yields decreased with the increase of O2 concentrations. When the O2 concentration was 10%, the gas yield reached a minimum and the liquid reached a maximum correspondingly. When the O2 concentration increased from 6% to 10%, the peak concentrations of CO and CH4 in the gas yield increased. However, when the O2 concentration exceeded 10%, CO and CH4 concentrations decreased. As O2 concentration varied from 6% to 12%, CO2 concentration increased continuously. This study provides a fundamental insight that the reaction processes could be well regulated by means of adjusting the feed air in practical units.

Risk of New Vertebral Fracture and Combination Therapy with Zoledronic Acid and Teriparatide in Diabetic Patients after Percutaneous Kyphoplasty

Zhang Jian,Yan Bin,Chen Zhe,Zheng Zhaomin,Yang Changsheng 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.5

Study Design: This was a retrospective clinical study. Purpose: This study aimed to evaluate the effect of combination therapy with zoledronic acid and teriparatide on the risk of new vertebral fracture (NVF) in type 2 diabetes mellitus (T2DM) patients after percutaneous kyphoplasty (PKP). Overview of Literature: Although T2DM had been associated with bone fragility and increased fracture risk, it remains unknown whether patients with T2DM could expect similar benefit from the combination therapy with zoledronic acid and teriparatide following PKP. Methods: Total 106 diabetic patients who had undergone PKP and had received anti-osteoporosis treatment for osteoporotic vertebral compression fracture were enrolled and allocated into the following two groups: group I (n=52, zoledronic acid) and group II (n=54, zoledronic acid plus teriparatide). The operating time, bone cement volume, and complications related to anti-osteoporosis treatment or PKP, if any, were recorded. The Visual Analog Scale (VAS) score and Oswestry Disability Index (ODI) were assessed at admission, at discharge, and at the final follow-up. Dual-energy X-ray absorptiometry scan of the hip for the measurement of the bone mineral density (BMD) was performed preoperatively and at the final follow-up for all the patients. Results: There was no significant difference in the age, body mass index, bone cement volume, or follow-up time of the groups. The mean follow-up duration was 22.5±1.6 months. All the patients had improved VAS and ODI, and group II had significantly better clinical outcomes than group I. All the patients had increased BMD at the latest follow-up, while group II exhibited significantly more improvement. The prevalence of NVF was lower in group II (11.5% vs. 7.4%, p=0.523). Male patients had a higher prevalence of NVF although the difference was not statistically significant. Conclusions: Combination therapy with zoledronic acid and teriparatide could improve the clinical outcomes, and BMD and had the potential to reduce NVF in diabetic patients following PKP.

Correlation Between the Microstructural Defects and Residual Stress in a Single Crystal Nickel-Based Superalloy During Different Creep Stages

Fangjie Mo,Erdong Wu,Changsheng Zhang,Hong Wang,Zhengye Zhong,Jian Zhang,Bo Chen,Michael Hofmann,Weimin Gan,Guangai Sun 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5

The present work attempts to reveal the correlation between the microstructural defects and residual stress in the singlecrystal nickel-based superalloy, both of which play the signifi cant role on properties and performance. Neutron diff ractionwas employed to investigate the microstructural defects and residual stresses in a single crystal (SC) nickel-based superalloy,which was subjected to creeping under 220 MPa and 1000 °C for different times. The measured superlattice andfundamental lattice refl ections confi rm that the mismatch and tetragonal distortions with c / a > 1 exist in the SC superalloy. At the initially unstrained state, there exists the angular distortion between γ and γ’ phases with small triaxial compressivestresses, ensuring the structural stability of the superalloy. After creeping, the tetragonal distortion for the γ phase is largerthan that for the γ’ phase. With increasing the creeping time, the mismatch between γ and γ’ phases increases to the maximum,then decreases gradually and fi nally remains unchanged. The macroscopic residual stress shows a similar behaviorwith the mismatch, indicating the correlation between them. Based on the model of shear and dislocations, the evolution ofmicrostructural defects and residual stress are reasonably explained. The effect of shear is dominant at the primary creepstage, which greatly enlarges the mismatch and the residual stress. The dislocations weaken the effect of shear for the furthercreep stage, resulting in the decrease of the mismatch and relaxation of the residual stress. Those fi ndings add some helpfulunderstanding into the microstructure-performance relationship in the SC nickel-based superalloy, which might provide theinsight to materials design and applications.

Layered 50Cr6Ni2/Stellite X-40 Multi-material Fabricated by Direct Laser Deposition: Characterization and Properties

Hongjie Wu,Suiyuan Chen,Chenyi Zhang,Jing Liang,Changsheng Liu,Mei Wang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.1

Fretting damage under high temperature corrosion and wear condition is one of the main factors that cause the failure of thekey parts of mechanical and electrical equipment, and laser cladding wear-resistant and corrosion-resistant coating is the maintechnology to repair these failure key parts. In this paper, the layered 50Cr6Ni2/Stellite X-40 multi-material was prepared bydirect laser deposition (DLD) using wear-resistant Fe-based alloy and corrosion-resistant Co-based alloy, to meet the needsof repair and remanufacturing of key parts with fretting damage. The results show that the layered 50Cr6Ni2/Stellite X-40composite material retains their respective microstructures and excellent properties. The microstructure of the 50Cr6Ni2layer mainly contains martensite and granular bainite, the microstructure of the Stellite X-40 layer consists of dendrite andeutectic structure. The layered 50Cr6Ni2/Stellite X-40 composite material has both good wear resistance (wear mass loss is1.0 mg) and good corrosion resistance (− 0.37549 of Ecorrand 0.00032 of icorr). The DLD layered 50Cr6Ni2/Stellite X-40composite material could meet the demand of short stress path rolling mill remanufacturing.

Laser Cladding Novel NiCrSiFeBW–CeO2 Coating with Both High Wear and Corrosion Resistance

Min Guo,Suiyuan Chen,Fanmin Shang,Jing Liang,Tong Cui,Changsheng Liu,Mei Wang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8

In order to obtain the high wear- and corrosion-resistant nickel based alloy coatings for laser remanufacturing fretting damaged metal parts which are serviced under high-temperature corrosion and wear conditions, a novel NiCrSiFeBW–CeO2alloy powder was designed by increasing the content of B and Si, adding tungsten and CeO2 using JMatpro software onthe basis of Ni60 alloy powder composition, and the NiCrSiFeBW–CeO2 coating was successfully cladded on 45# steelunder diferent laser energy area densities. The microstructure, wear and corrosion behaviors of the NiCrSiFeBW–CeO2coatings were systematically studied. The results show that novel NiCrSiFeBW–CeO2 coating produced by laser claddingnot only has no cracks but also has both high wear resistance and corrosion resistance due to some ultra-fne compoundparticle phases in situ generated in its structure. Among these phases, the B3Cr5, CrB4, (Cr, Ni)3C2, Cr7C3, W3Cr12Si5 and(Fe, Ni)5Si3 played a signifcant role in reinforcing the wear resistance of the coating, while the B3Cr5, W3Cr12Si5 and CrB4enhanced the corrosion resistance of the coating. The novel NiCrSiFeBW–CeO2 coating prepared under 100 J/mm2EADhas the best comprehensive performance, the wear loss is 7.53×10−5 mm3/N, the Ecorr is − 0.1738 V. Compared with Ni60alloy coating, the novel Ni-based coating not only has a better laser cladded formability but also similar wear resistance andbetter corrosion-resistance. It provides a reference for repairing fretting damaged metal parts by laser cladding the nickelbased coating with high wear and corrosion resistance.