Design and Testing of a Mechanical Power Take-off System for Rolling-type Wave Energy Converter

Yichen Jiang,Yuhao Peng,Yuan Sun,Zhi Zong,Lei Sun 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.5

Salter’s Duck can convert wave energy to mechanical energy with high efficiency up to 90%. The limitations and challenges in the usage of Salter’s Duck for energy production include preventing hydraulic system from the risk of leaking hydraulic oil and removing complex huge fixed bracket. This paper presents the conceptual design and an experimental investigation of a mechanical power-take-off (PTO) system for the floating Salter’s Duck. The PTO system is fully installed inside of the Salter’s Duck. It consists of double counter-rotating flywheels converting the bi-directional rotation of the wave energy converter into a stable unidirectional rotation that drives a rotary generator to produce electricity. The bi-to-unidirectional function is achieved through inertial wheels, thus the novel PTO system is free of large supporting structures and hydraulic cylinders. In this paper, a detailed conceptual PTO design is proposed firstly. Further, the influence of the swing amplitude and rotation period of the wave energy converter on the power extraction efficiency is investigated. Then, the influence of the electrical load on the power-extraction efficiency is researched. In the end, the effect of the speed increasing ratio on the mechanical efficiency is examined. The experimental results show that the new type of generator mechanism can produce electricity stably.

Analysis of Status of Smartphone Photography and Socialization among the Elderly People in Nanjing Community

Jiabei Jiang,Weiwei Zhang,Jihong Jeung,Yuhao Huang 한국HCI학회 2020 한국HCI학회 학술대회 Vol.2020 No.2

With the ubiquity of smart devices and the aging population,more and more elderly people begin to use smart devices. Their main application ranges from phone calls and messaging to payment and navigation. Many studies have been conducted on the evaluation of usability of smart device for the elderly. However, few of them were focused on the characteristics and difficulties of the elderly people in smartphone photography. This study took the elderly people as the target to research on their experience of using photo-shooting applications. Based on questionnaires and interviews, combined with qualitative and quantitative researches, this paper explores the social influence of taking pictures with smartphones on both the physical and the psychological aspects. The results show: 1)The majority of elderly people use smartphone photography; gender and living conditions are the main factors affecting shooting experience, while age is not; Smartphone photography has changed the way they think and their life habits; 2)Very few of the elderly share their photos on social network service(SNS) because of the risk of privacy leakage and mis-operation; while viewing family and friends’ photos could bring them senses of participation; 3)The main difficulties for the elderly are album management and the lack of affordance of the interface elements; 4)The needs of the elderly people in smartphone photography cannot be ignored.

Study on Tribological Properties of Laser-Textured Plunger in Methanol Engine

Bifeng Yin,Yuhao Jiang,Bo Xu,Hekun Jia,Xuefeng Wang 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.4

Considering the eccentricity and deformation of the plunger, a lubrication model of laser-textured plunger pair was established to research friction-and-wear performance of typical surface texture on the plunger under diesel and methanol lubrication. The calculation results show that for the non-textured plunger, the oil film thickness and fluid friction under methanol lubrication are lower than diesel lubrication, and the asperity friction was greater than diesel lubrication, indicating that methanol may deteriorate the lubrication performance of the plunger surface. After texturing the plunger, the oil film thickness and fluid friction during methanol lubrication are greater than the non-textured scheme, and the asperity friction is lower than the non-textured scheme, which means that the surface texture has the potential to improve the lubrication performance of the plunger. The friction and wear tests results indicate that the average friction coefficient of the textured plunger is reduced by 3.4 ~ 6.2 % compared with the non-textured plunger in methanol lubrication. The lubrication performance of the textured plunger during methanol lubrication reaches the level of the non-textured plunger in diesel lubrication. After the wear test, the surface wear depth of the textured plunger is reduced by 16.2 % compared with the non-textured plunger in methanol lubrication condition.

Data-driven intelligent computational design for products: method, techniques, and applications

Yang Maolin,Jiang Pingyu,Zang Tianshuo,Liu Yuhao 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.4

Data-driven intelligent computational design (DICD) is a research hotspot that emerged under fast-developing artificial intelligence. It emphasizes utilizing deep learning algorithms to extract and represent the design features hidden in historical or fabricated design process data and then learn the combination and mapping patterns of these design features for design solution retrieval, generation, optimization, evaluation, etc. Due to its capability of automatically and efficiently generating design solutions and thus supporting human-in-the-loop intelligent and innovative design activities, DICD has drawn the attention of both academic and industrial fields. However, as an emerging research subject, many unexplored issues still limit the development and application of DICD, such as specific dataset building, engineering design-related feature engineering, systematic methods and techniques for DICD implementation in the entire product design process, etc. In this regard, a systematic and operable road map for DICD implementation from a full-process perspective is established, including a general workflow for DICD project planning, an overall framework for DICD project implementation, the common mechanisms and calculation principles during DICD, key enabling technologies for detailed DICD implementation, and three case scenarios of DICD application. The road map can help academic researchers to locate their specific research directions for the further development of DICD and provide operable guidance for the engineers in their specific DICD applications.

Involvement of DJ-1 in the pathogenesis of intervertebral disc degeneration via hexokinase 2-mediated mitophagy

Lin Jialiang,Wang Longjie,Wu Yuhao,Xiang Qian,Zhao Yongzhao,Zheng Xuanqi,Jiang Shuai,Sun Zhuoran,Fan Dongwei,Li Weishi 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Intervertebral disc degeneration (IDD) is an important pathological basis for degenerative spinal diseases and is involved in mitophagy dysfunction. However, the molecular mechanisms underlying mitophagy regulation in IDD remain unclear. This study aimed to clarify the role of DJ-1 in regulating mitophagy during IDD pathogenesis. Here, we showed that the mitochondrial localization of DJ-1 in nucleus pulposus cells (NPCs) first increased and then decreased in response to oxidative stress. Subsequently, loss- and gain-of-function experiments revealed that overexpression of DJ-1 in NPCs inhibited oxidative stress-induced mitochondrial dysfunction and mitochondria-dependent apoptosis, whereas knockdown of DJ-1 had the opposite effect. Mechanistically, mitochondrial translocation of DJ-1 promoted the recruitment of hexokinase 2 (HK2) to damaged mitochondria by activating Akt and subsequently Parkin-dependent mitophagy to inhibit oxidative stress-induced apoptosis in NPCs. However, silencing Parkin, reducing mitochondrial recruitment of HK2, or inhibiting Akt activation suppressed DJ-1-mediated mitophagy. Furthermore, overexpression of DJ-1 ameliorated IDD in rats through HK2-mediated mitophagy. Taken together, these findings indicate that DJ-1 promotes HK2-mediated mitophagy under oxidative stress conditions to inhibit mitochondria-dependent apoptosis in NPCs and could be a therapeutic target for IDD.

ADAPTABILITY OF LASER TEXTURED LINER TO THE EFFECTS OF METHANOL DILUTING OIL ON TRIBOLOGICAL PROPERTIES

Jia He Kun,Xu Bo,Yin Bifeng,Jiang Yuhao,Hu Nanrong 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.2

With the increase of methanol diluting lubrication oil, the dynamic viscosity of the mixture presents a downward trend, the total acid number grows while the total base number declines, and the corrosion degree of copper strip upgrades, which indicates that methanol dilution has negative effects on lubrication and anti-corrosion performance of oil. According to ball-on-plate friction test results, the friction coefficient and surface wear of this pair increase in turn with the rising methanol dilution rate, which tends to deteriorate the tribological performance of key friction pairs in methanol engine. After laser surface texturing cylinder liner, the friction coefficient of ring/liner pair is reduced, and the anti-friction effect is enhanced with the rising methanol dilution rate, because the oil storage capacity of textured micro-dimples on liner surface can improve the lubrication of ring/liner pair and reduce asperity contact. Moreover, the micro-dimples can store debris generated in the reciprocating friction process of this pair, so as to alleviate surface wear caused by abrasive wear, and improve the wear resistance of cylinder liner. Therefore, laser texturing cylinder liner can compensate the deterioration of friction and wear performance of ring/liner pair caused by methanol diluting oil with good lubrication adaptability.