Investigation of Grinding Characteristic using Nanofluid Minimum Quantity Lubrication

Cong Mao,Xiaojun Tang,Hongfu Zou,Xiangming Huang,Zhixiong Zhou 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

Conventional grinding fluid is widely used in grinding process, which results in high consumption and impacting the environment. The promising alternative to conventional dry and fluid coolant application is minimum quantity lubrication (MQL). It is known that the cooling and lubrication performance of the grinding fluid is the key technical area for the success application of MQL grinding process. In this study, Water based Al2O3 nanofluid was applied to grinding process with MQL approach for its excellent convection heat transfer and thermal conductivity properties. The grinding characteristics of hardened AISI 52100 steel were investigated and compared with those of wet, dry and pure water MQL grinding. Experimental results show that water based Al2O3 nanofluid MQL grinding can significantly reduce the grinding temperature, decrease the grinding forces, improve the ground surface morphology and reduce the surface roughness in comparison to pure water MQL grinding. Furthermore, the cooling and lubricating mechanism for nanofluid MQL grinding was discussed in detail.

Carbon-silica composites supported Pt as catalyst for asymmetric hydrogenation of ethyl 2-oxo-4-phenylbutyrate

Cong Mao,Jie Zhang,Meitian Xiao,Yongjun Liu,Xueqin Zhang 한국물리학회 2018 Current Applied Physics Vol.18 No.12

Mesoporous carbon-silica composites supported Pt nanoparticle catalysts (Pt/MCS) were firstly applied to the heterogeneous asymmetric hydrogenation of ethyl 2-oxo-4-phenylbutyrate (EOPB). A series of different silica contents were investigated in the fabrication of this mesoporous material. When the volume of added tetraethyl orthosilicate (TEOS) during the preparation of composites is 8 mL, Pt/MCS-8 holds carbon and silica as the main components and possesses relatively strong acidity, mesoporous structures with micropores, appropriate Pt nanoparticle size and high dispersibility showing by XRD, XPS, TPD, N2 sorption and TEM. These properties cause its good catalytic performance in the heterogeneous asymmetric hydrogenation of EOPB with the enantiomeric excess value and conversion up to 85.6% and 97.8%, respectively.

Tensile Behaviors of Laser-Discrete-Quenched Substrate/Nickel Coating of Electroplated Grinding Wheel

Cong Mao,Yujie Zhong,Yongle Hu,Weidong Tang,Z. M. Bi,Zhaohong Lei,Changchun Jiang,Aimin Tang 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.5

Electroplated grinding wheel has significant advantages, such as longer service life, higher removal rate, reduction of preparation work, reapplication of the wheel bub. Then it is an efficient, green and eco-friendly abrasive tool. In order to reveal the mechanism that the service life of the electroplated grinding wheel is increased by pre-quenched substrate, the tensile behavior and interfacial stresses of the laser-discrete-quenched substrate/nickel coating were studied through tensile experiment and simulation. The results show that random initial cracks appear in the nickel coating over the unquenched zone before the tensile experiment. There is an inter-diffusion region at the interface of steel substrate and nickel coating; in comparison with the unquenched zone, the size of the inter-diffusion region in the laser-quenched zone was decreased significantly (e.g., 1.2 μm in comparison with 2.6 μm). In tensile testing, the coating over the pre-quenched specimen remains bonded with the substrate firmly even the fracture occurs. In contrast, the damages in the forms of blistering, stripping and exfoliating occurred in the coating over the unquenched specimen. When a fracture occurs, there is a significant difference of the ultimate strains of quenched and unquenched zones; the ultimate strain of quenched zone is 0.0714, while that of the unquenched zone is 0.1667. At the bonding interface, the pre-quenched specimen ensured the overall shear stress and the maximum normal stress, which are lower than those of unquenched specimen. The initial cracks in pre-quenched specimen propagate during stretching, the effect of the absorbed strain energy reduces strain mismatch between the substrate and coating at the interface, and this improves the bonding strength at the interface of the laser-discrete-quenched specimen significantly.

Review of the Research on the Optimization of the Energy Consumption of the Cloud Platform

Chun-mao Jiang,Yi-bing Li,Li Zhi-cong 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.8

Cloud platform is a basic platform to support large data, large-scale and high-frequency access computing. The high-energy consumption of the cloud platform and the schedule of multi-constrained combination in cloud applications is challenging issues faced by the cloud computing. We conducted a systematic review in this paper for the energy consumption of a cloud platform, and pointed out the existing problems, and put forward ideas to solve the above problems by constructing the four-level system. Firstly, by conducting virtualization management to the physical resources in the cloud to form the layer of virtual resource. Then, named as presentation layer, to build a formal model of cloud application multi_attribute with effective description, measurement, calculation. Based on this proposed scheduling application layer enables cloud applications to meet the multiple objectives with multi-attribute, heuristic, feedback, iterative scheduling and cloud resources, energy optimization. It laid the foundation for the formation of cloud platform architecture, key technologies and algorithms, which satisfy the multiple objectives: the maximum possible scheduling of the multi-attribute combination constraint application, the optimization for energy consumption and resources in cloud computing.

Porous Titanium Scaffolds with Aligned Lamellar Pore Channels by Directional Freeze‑Casting from Aqueous TiH2 Slurries

Mengchen Mao,Yufei Tang,Kang Zhao,Zihao Duan,Cong Wu 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2

Porous titanium scaffolds with aligned lamellar pore channels and smooth inner walls were fabricated by directional freezecasting using aqueous TiH2slurries. The formation of dendrites was inhibited by increasing the TiH2content in slurry. Thepore structures and compression strengths of porous titanium scaffolds that were made with different solid contents werecharacterized. The formation mechanism of aligned lamellar pore channels and the reason for the improvement of compressionstrength were analyzed. With increasing TiH2content in slurry, the open porosity reduced from 38.57 to 29.03% whilelamellar spacing decreased. Young’s modulus was decreased with the increasing open porosity. Directional lamellar porechannels were obtained by controlling the TiH2content in slurry, which can reduce the number of branches and preventstress concentrations during compression. Also, the porous titanium scaffolds prepared by this process had a good biocompatibilitywith osteoblasts.

Preparation of bioactive nano-hydroxyapatite coating for artificial cornea

Run-Rong Lin,Xuan Mao,Qi-Cong Yu,Bai-Hua Tan 한국물리학회 2007 Current Applied Physics Vol.7 No.s1

Bioactive coatings containing hydroxyapatite(HA) nano crystals were prepared on PHEMA membrane by a sol dipping method.A cellcoating and the aggregation degree of HA particles inuence the adhesion of the cornea broblasts to the membrane, which dependsdramatically on the weight ratio between the nano-HA and the dispersant. The optimal condition of the coating preparation is with adispersant/HA = 1.25 weight ratio. The PHEMA membrane covered with nano-HA coating is promising for articial cornea use.

Synthesis method based on solution regions for planar four-bar straight-line linkages

Yin Lairong,Han Jianyou,Mao Cong,Huang Juan,Yang Tong 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.10

An analytical method for synthesizing and selecting desired four-bar straight-line mechanisms based on solution regions is presented. Given two fixed pivots, the point position and direction of the target straight-line, an infinite number of mechanism solutions can be produced by employing this method, both in the general case and all three special cases. Unifying the straight-line direction and the displacement from the given point to the instant center into the same form with different angles as parameters, infinite mechanism solutions can be expressed with different solution region charts. The mechanism property graphs have been computed to enable the designers to find out the involved mechanism information more intuitively and avoid aimlessness in selecting optimal mechanisms.

Ultrasonic Osteotome Assisted Posterior Endoscopic Cervical Foraminotomy in the Treatment of Cervical Spondylotic Radiculopathy Due to Osseous Foraminal Stenosis

Ye Jiang,Chen Li,Lutao Yuan,Cong Luo,Yuhang Mao,Yong Yu 대한신경외과학회 2023 Journal of Korean neurosurgical society Vol.66 No.4

Objective : To investigate the efficacy and safety of the posterior endoscopic cervical foraminotomy (PECF) using ultrasonic osteotome for the treatment of cervical osseous foraminal stenosis,focusing on introduction of the advantages of ultrasonic osteotome in partial pediculectomy and ventral osteophyte resection in PECF. Methods : Nineteen patients with cervical osseous foraminal stenosis who underwent PECF using ultrasonic osteotome in our institution between April 2018 and April 2021 were enrolled in this study. All the patients were followed up more than 12 months. The patients’ medical data, as well as pre- and postoperative radiologic findings were thoroughly investigated. The visual analogue score (VAS), Japanese Orthopaedic Association (JOA) score, cervical dysfunction index (Neck disability index, NDI), and modified MacNab criteria were used to assess the surgical efficacy. Results : All the patients were successfully treated with PECF using ultrasonic osteotome. The pre- and postoperative VAS, NDI, and JOA scores were significantly improved (p<0.05). According to the modified MacNab criteria, 17 patients were assessed as “excellent”, two patients were assessed as “good” at the last follow-up. There was no dura tear, nerve root damage, incision infection, neck deformity, or other complications. Conclusion : Adequate nerve root decompression can be accomplished successfully with the help of ultrasonic osteotome in PECF, which has the advantage of reducing the probability of damage to the nerve root and dura mater, in addition to the original merits of endoscopic surgery.

Melatonin protects endothelial progenitor L255cells against AGE-induced apoptosis via autophagy flux stimulation and promotes wound healing in diabetic mice

Haiming Jin,Zengjie Zhang,Chengui Wang,Qian Tang,Jianle Wang,Xueqin Bai,Qingqing Wang,Majid Nisar,Naifeng Tian,Quan Wang,Cong Mao,Xiaolei Zhang,Xiangyang Wang 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Wound healing is delayed in diabetic patients. Increased apoptosis and endothelial progenitor cell (EPC) dysfunction are implicated in delayed diabetic wound healing. Melatonin, a major secretory product of the pineal gland, promotes diabetic wound healing; however, its mechanism of action remains unclear. Here, EPCs were isolated from the bone marrow of mice. Treatment of EPCs with melatonin alleviated advanced glycation end product (AGE)-induced apoptosis and cellular dysfunction. We further examined autophagy flux after melatonin treatment and found increased light chain 3 (LC3) and p62 protein levels in AGE-treated EPCs. However, lysosome-associated membrane protein 2 expression was decreased, indicating that autophagy flux was impaired in EPCs treated with AGEs. We then evaluated autophagy flux after melatonin treatment and found that melatonin increased the LC3 levels, but attenuated the accumulation of p62, suggesting a stimulatory effect of melatonin on autophagy flux. Blockage of autophagy flux by chloroquine partially abolished the protective effects of melatonin, indicating that autophagy flux is involved in the protective effects of melatonin. Furthermore, we found that the AMPK/mTOR signaling pathway is involved in autophagy flux stimulation by melatonin. An in vivo study also illustrated that melatonin treatment ameliorated impaired wound healing in a streptozotocin-induced diabetic wound healing model. Thus, our study shows that melatonin protects EPCs against apoptosis and dysfunction via autophagy flux stimulation and ameliorates impaired wound healing in vivo, providing insight into its mechanism of action in diabetic wound healing.