Flow structure of conical distributed multiple gas jets injected into a water chamber

Jiajun Zhao,Yonggang Yu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4

Based on an underwater gun firing project, a mock bullet with several holes on the head was designed and experimented to observe the combustion gas injected into a cylindrical water chamber through this mock bullet. The combustion gas jets contain one vertical central jet and 4 to 8 slant lateral jets. A high speed camera system was used to record the expansion of gas jets in the experimental study. In numerical simulations, the Euler two-fluid model and volume of fluid method were adopted to describe the gas-liquid flow. The results show the backflow zone in lateral jet is the main factor influencing the gas-liquid turbulent mixing in downstream. On cross sections, the gas volume fraction increased with time but the growth rate decreased. With a change of nozzle structure, the gas fraction was more affected than the shock structure.

A Novel Framework for Online Amnesic Trajectory Compression in Resource-Constrained Environments

Liu, Jiajun,Zhao, Kun,Sommer, Philipp,Shang, Shuo,Kusy, Brano,Lee, Jae-Gil,Jurdak, Raja IEEE 2016 IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERIN Vol.28 No.11

<P>State-of-the-art trajectory compression methods usually involve high space-time complexity or yield unsatisfactory compression rates, leading to rapid exhaustion of memory, computation, storage, and energy resources. Their ability is commonly limited when operating in a resource-constrained environment especially when the data volume (even when compressed) far exceeds the storage limit. Hence, we propose a novel online framework for error-bounded trajectory compression and ageing called the Amnesic Bounded Quadrant System (ABQS), whose core is the Bounded Quadrant System (BQS) algorithm family that includes a normal version (BQS), Fast version (FBQS), and a Progressive version (PBQS). ABQS intelligently manages a given storage and compresses the trajectories with different error tolerances subject to their ages. In the experiments, we conduct comprehensive evaluations for the BQS algorithm family and the ABQS framework. Using empirical GPS traces from flying foxes and cars, and synthetic data from simulation, we demonstrate the effectiveness of the standalone BQS algorithms in significantly reducing the time and space complexity of trajectory compression, while greatly improving the compression rates of the state-of-the-art algorithms (up to 45 percent). We also show that the operational time of the target resource-constrained hardware platform can be prolonged by up to 41 percent. We then verify that with ABQS, given data volumes that are far greater than storage space, ABQS is able to achieve 15 to 400 times smaller errors than the baselines. We also show that the algorithm is robust to extreme trajectory shapes.</P>

Fermentation characteristics and microbial community composition of wet brewer's grains and corn stover mixed silage prepared with cellulase and lactic acid bacteria supplementation

Guoqiang Zhao,Hao Wu,Yangyuan Li,Li Li,Jiajun He,Xinjian Yang,Xiangxue Xie Asian Australasian Association of Animal Productio 2024 Animal Bioscience Vol.37 No.1

Objective: The objective of this study was to investigate how cellulase or/and lactic acid bacteria (LAB) affected the fermentation characteristic and microbial community in wet brewer's grains (WBG) and corn stover (CS) mixed silage. Methods: The WBG was mixed thoroughly with the CS at 7:3 (w/w). Four treatment groups were studied: i) CON, no additives; ii) CEL, added cellulase (120 U/g fresh matter [FM]), iii) LAB, added LAB (2×10⁶ cfu/g FM), and iv) CLA, added cellulase (120 U/g FM) and LAB (2×10⁶ cfu/g FM). Results: All additive-treated groups showed higher fermentation quality over the 30 d ensiling period. As these groups exhibited higher (p<0.05) LAB counts and lactic acid (LA) content, along with lower pH value and ammonia-nitrogen (NH₃-N) content than the control. Specifically, cellulase-treated groups (CEL and CLA) showed lower (p<0.05) neutral detergent fiber and acid detergent fiber contents than other groups. All additives increased the abundance of beneficial bacteria (Firmicutes, Lactiplantibacillus, and Limosilactobacillus) while they decreased abundance of Proteobacteria and microbial diversity as well. Conclusion: The combined application of cellulase and LAB could effectively improve the fermentation quality and microbial community of the WBG and CS mixed silage.

Effects of applying cellulase and starch on the fermentation characteristics and microbial communities of Napier grass (Pennisetum purpureum Schum.) silage

( Guoqiang Zhao ),( Hao Wu ),( Li Li ),( Jiajun He ),( Zhichao Hu ),( Xinjian Yang ),( Xiangxue Xie ) 한국축산학회 2021 한국축산학회지 Vol.63 No.6

This study investigated the effects of applying cellulase and starch on the fermentation characteristics and microbial communities of Napier grass silage after ensiling for 30 d. Three groups were studied: No additives (control); added cellulase (Group 1); and added cellulase and starch (Group 2). The results showed that the addition of cellulase and starch decreased the crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and pH significantly (p < 0.05) and increased water-soluble carbohydrate (WSC) content (p < 0.05). The addition of additives in two treated groups exerted a positive effect on the lactic acid (LA) content, lactic acid bacteria (LAB) population, and lactic acid / acetic acid (LA/AA) ratio, even the changes were not significant (p > 0.05). Calculation of Flieg’s scores indicated that cellulase application increased silage quality to some extent, while the application of cellulase and starch together significantly improved fermentation (p < 0.05). Compared with the control, both additive groups showed increased microbial diversity after ensiling with an abundance of favorable bacteria including Firmicutes and Weissella, and the bacteria including Proteobacteria, Bacteroidetes, Acinetobacter increased as well. For alpha diversity analysis, the combined application of cellulase and starch in Group 2 gave significant increases in all indices (p < 0.05). The study demonstrated that the application of cellulase and starch can increase the quality of Napier grass preserved as silage.

Local Bond Stress-Slip Model of High-Strength Stainless Steel Wire Ropes in ECC

Ke Li,Dapeng Zhao,Jiajun Fan,Juntao Zhu 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.5

Engineered cementitious composites (ECC) reinforced with high-strength stainless steel wire ropes (HSSSWR) is a new composite that has attracted much attention. Comprehensive understanding of the local bond stress-slip relationship of HSSSWR in ECC is a significant aspect to popularize the application of this new composite. In this research, the local bond stress-slip relationship between HSSSWR and ECC was investigated experimentally and theoretically, considering the influences of bond lengths, nominal diameters of HSSSWR and compressive strength of ECC. In order to accurately predict the bond stress and slip at different positions along the embedded length, a local bond stress-slip model was proposed for HSSSWR-ECC interface, and the model parameters were determined based on the pull-out test results and microsegment analysis of HSSSWR in ECC by using a nested iteration procedure. Furthermore, the three-dimension (3D) nonlinear finite element (FE) modeling method by using the proposed model was used to predict the bond-slip performance of HSSSWR in ECC. Finally, the global load-slip relationships calculated by using the iterative procedure and the 3D FE modeling method were compared with test results, which validated the acceptability of the developed local bond stress-slip model and the FE modeling method.

Chronic ethanol feeding impairs AMPK and MEF2 expression and is associated with GLUT4 decrease in rat myocardium

LiYong Chen,Jing Zhou,JiaJun Zhao,FuRong Wang,XiangLan Sun,Ling Gao,YuLian Jiao,XiaoLei Hou,ChengYong Qin 생화학분자생물학회 2010 Experimental and molecular medicine Vol.42 No.3

Chronic and heavy alcohol consumption is one of the causes of heart diseases. However, the effects of ethanol on insulin sensitivity in myocardium has been unclear. To investigate the effects of ethanol on the expression of AMP-activated protein kinase (AMPK), myocyte enhancer factor 2 (MEF2) and glucose transporter 4 (GLUT4), all of which are involved in the regulation of insulin sensitivity, in the myocardium, we performed three parts of experiments in vivo and in vitro. I: Rats were injected with 5-amino-4-imidazolecarboxamide ribonucleotide (AICAR, 0.8 mg.kg-1) for 2 h. II:Rats received different dose (0.5, 2.5 or 5 g.kg-1.d-1) of ethanol for 22-week. III: Primary neonatal rat cardiomyocytes were isolated and treated with or without 100 mM ethanol or 1 mM AICAR for 4 h. The cardiac protein and mRNA expression of AMPKα subunits, MEF2and GLUT4 were observed by western-blotting and RT-PCR, respectively. Serum TNFα levels were assessed by ELISA. The results showed chronic ethanol exposure induced insulin resistance. Ethanol decreased the mRNA levels of AMPKα1 and α2, the protein levels of total- and phospho-AMPKα in cardiomyocytes. Similarly, ethanol showed inhibitory effects on both the mRNA and protein levels of MEF2A and 2D,and GLUT4 in a dose-response-like fashion. Correlation analysis implied an association between phospho-AMPKα and MEF2A or MEF2D, and between the levels of MEF2 protein and GLUT4 transcription. In addition,ethanol elevated serum TNFα level. Taken together,chronic ethanol exposure decreases the expression of AMPKα and MEF2, and is associated with GLUT4 decline in rat myocardium.

Co-simulation of self-propelled artillery based on virtual prototype technology

Zhangxia Guo,Zekun Yuan,Yuliang Yang,Yanxiang Jin,Jiajun Zhao,Taiyang Li 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

In present study, a virtual prototype of self-propelled artillery was constructed based on virtual prototype technology, and the whole impact process of artillery firing simulation was completed using ADAMS and AMEsim software. Results showed that the constructed artillery firing simulation system was reasonable. It could add a recoil dynamic response suitable for live firing to the tested artillery and could detect the vibration response characteristics of the artillery through the test device. Through numerical simulation, a quantitative analysis of artillery firing stability, stress state, and fatigue life under different working conditions was performed. All simulation results were in good agreement with the real situation. This research provides a certain reference for the evaluation of artillery firing stability and lays a good theoretical foundation for the engineering development and practical application of the test device.

Effects of Diosgenin on Cell Proliferation Induced by IGF-1 in Primary Human Thyrocytes

Dezhi Bian,Zhiwei Li,Hongyan Ma,Sumin Mu,Chunyan Ma,Bin Cui,Ling Gao,Jiajun Zhao 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.6

Others and our previous studies showed that the increase of IGF-1 was involved in the formation of goiter. Our aim here was to evaluate the possible effects of diosgenin on cell proliferation induced by IGF-1 in primary human thyroid cells. The cells were treated with or without different concentrations of diosgenin in the present or absent of IGF-1 for 24, 48 and 72 h, respectively. Cell viability was determined by MTT, and cell proliferation was tested by EdU assay, and cell cycle analysis was performed by FACS. In addition, Cyclin D1 and B1 protein expression was tested by Western Blotting, respectively. We found that IGF-1 promoted cell cycle progression to S phase and increased the primary human thyroid cells proliferation. Diosgenin decreased the protein expression of cyclin D1 and resulted in cell G_0 /G_1 arrest. Importantly, when the human thyrocytes were exposed to diosgenin in the present of IGF-1,the IGF-1 inducing proliferation was significantly decreased and the proportion of the cells in G_0 /G_1 phase was increased, while that of S phase was decreased. This study shows that diosgenin inhibited cell proliferation, caused G_0 /G_1 arrest, and could inhibit cell proliferation induced by IGF-1 in primary human thyroid cells.