The Evaluation of the Hydrogeological Parameters of a Field Pumping Test within Multi-layer Unconfined Pebble Aquifers: A Case Study

Jianjun Ma,Da Li,Man Wang 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.10

This paper presents a case study of field pumping tests and the evaluation of the hydrogeological parameters of the unconfined pebble aquifers in the test site located at Shijiawan station in Luoyang City, China, which guarantees the construction safety of Metro Line 1. Multiple groups of single-well pumping tests and one group-well pumping test were conducted to obtain the aquifers' hydrogeological parameters. Then, a combination of theoretical analysis and numerical simulation was used to evaluate the aquifers' hydrogeological parameters. The analytical solutions were obtained for the unconfined, anisotropic pebble aquifers using the Neuman model. The numerical simulation was established via the finite element method (FEM). The calculation results indicate that the theoretical analysis and numerical simulation parameters are well matched. Moreover, the results of the numerical method which considers the heterogeneous and horizontal isotropic characteristics of the pebble stratum, as well as the hydrogeological parameters are more reliable than the results obtained by the theoretical analysis. The pumping tests also indicate that the supporting structure plays a significant role in waterproofing during dewatering construction.

Effect of residual stress on the hydrogen diffusion near the crack tip in the weldment

Jianjun Chen,Yong Wha Ma,Doo Il Won,Kwan-Ju Lee,Kee Bong Yoon 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

In this paper the hydrogen diffusion in the weld structure containing defect was analyzed by the finite element method. The effect of the welding residual stress on the hydrogen distribution has been studied using a coupling analysis procedure conducted by Abaqus code. The hydrogen diffusion without the residual stress was also simulated for comparison. The results show that the hydrogen distribution changed significantly due to the existence of the residual stress. It is found that the residual stress not only increases the hydrogen concentration but also reduces the hydrogen concentration at different regions ahead of the crack tip.

The effects of a short sequence enhancer (50-GTGAAATAAATGCAAATAAAGT) and its derived sequences on green fluorescent protein expression

Zhihong Ma,Zhanjun Lv,Xiu-Fang Wang,Xiangyang Jing,Jianjun Cheng 한국유전학회 2014 Genes & Genomics Vol.36 No.4

Cis-regulatory elements are regions of DNAthat regulate the expression of genes located on that samemolecule of DNA. Though these elements are important forgene expression regulation, the functions of cis elementsremain largely unknown. To explore the mechanisms ofgene activation by short sequence enhancers, we examinedthe enhancer activity of short sequence DNA and itsderived sequences using a GFP expression system. Wefound that AA sequence (50-GTGAAATAAATGCAAATAAAGT) induced strong GFP gene expression, while7pieA (50-GTGAAAAAAATGCAAAAAAAGT) did not. We mutated the five T bases of the AA sequence to A, C orG. Our findings indicated that sequences retaining the 7thand/or 17th Ts possessed strong enhancer activity. RT-PCRand RNA synthesis inhibition analysis using actinomycin Drevealed that the enhanced GFP gene expression inducedby the AA sequence occurred at the transcriptional level. To determine whether the AA sequence formed a secondarystructure via atypical complementation, PAGE methodwas used, and the results showed that the AA sequenceformed a secondary structure. Our results support previousevidence that AATAAA is an important composition of ciselements (enhancer/promoter), and suggest that the formationof an unstable stem-loop structure via atypicalcomplementation may be a new mechanism of enhanceractivity.

Finite element study for determination of material's creep parameters from small punch test

Chen, Jianjun,Ma, Young-Wha,Yoon, Kee-Bong 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.6

Compared with the conventional tensile creep test, it is much more difficult to obtain the creep properties of a material by the small punch creep test due to the complex deformation response and stress distribution in the miniature specimen of the material. Although creep behavior has been investigated by the small punch test, most studies have been limited to a specimen geometry and therefore, cannot be extended to other conditions conveniently. In this study, a new developed analysis routine is presented to derive the creep parameters of a material using data obtained from the small punch creep test. With the aid of the finite element method, the displacement and the displacement rate of the small punch are obtained for different load levels. The relationship between the stress and creep strain of the specimen and the applied load and the punch displacement is obtained by a dimensional analysis and the membrane stretching model. The creep properties obtained from small punch tests and the conventional creep tests are also compared. The values of the creep properties between the two types of tests agree well with each other within an acceptable accuracy range. This indicates that it is possible to obtain the creep parameters of a material from the small punch creep test instead of the conventional creep test by the analysis routines proposed in this study. Some suggestions for data reduction of the small punch creep tests are also presented to obtain more accurate material creep parameters.

A New Method for Piping Risk Evaluation on Unconfined Aquifers under Dewatering of Deep Foundation Pits

Da Li,Jianjun Ma,Chaosheng Wang,Xiaojuan Gao,Mingjing Fang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

This paper presents a new method to evaluate the piping risk of unconfined sandy cobble aquifers during the dewatering of deep foundation pits. Firstly, the possibility of piping is judged according to the particle size distribution and pore diameter of the sandy cobble stratum. Secondly, the critical hydraulic gradients of particles with different sizes are calculated according to the pipe flow model. Thirdly, the hydraulic gradient around the foundation pit during the dewatering process is calculated by numerical method. Then, combined with the distribution of hydraulic gradient around the foundation pit and the critical hydraulic gradients of particles with different sizes, the range of moveable particles with different sizes in the surrounding stratum is evaluated. Finally, according to the sandy cobble aquifers conditions and the influence of particle movement on the stratum, the level of piping risk is determined. This method was successfully applied to evaluate the piping risk of Tawan Station in Luoyang Metro Line No.1, and according to the risk evaluation the pensile curtain was recommended for the retaining structure in this case. From the satisfied applications, this method is a reference for the evaluation of piping risk and selection of retaining structure when considering the impact of the dewatering in deep foundation pit with unconfined aquifers on the surrounding stratum.

An interval approach to robust design with parameter uncertainty

Ouyang, Linhan,Ma, Yizhong,Byun, Jai-Hyun,Wang, Jianjun,Tu, Yiliu Taylor Francis 2016 INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH - Vol.54 No.11

<P>In robust design, it is common to estimate empirical models that relate an output response variable to controllable input variables and uncontrollable noise variables from experimental data. However, when determining the optimal input settings that minimise output variability, parameter uncertainties in noise factors and response models are typically neglected. This article presents an interval robust design approach that takes parameter uncertainties into account through the confidence regions for these unknown parameters. To avoid obtaining an overly conservative design, the worst and best cases of mean squared error are both adopted to build an optimisation approach. The midpoint and radius of the interval are used to measure the location and dispersion performances, respectively. Meanwhile, a data-driven method is applied to obtain the relative weights of the location and dispersion performances in the optimisation approach. A simulation example and a case study using automobile manufacturing data from the dimensional tolerance design process are used to demonstrate the effectiveness of the proposed approach. The proposed approach of considering both uncertainties is shown to perform better than other approaches.</P>

Effect of keratinase on ileal amino acid digestibility in five feedstuffs fed to growing pigs

Chengfei Huang,Dongli Ma,Jianjun Zang,Bo Zhang,Brian Sun,Ling Liu,Shuai Zhang 아세아·태평양축산학회 2018 Animal Bioscience Vol.31 No.12

Objective: This study was conducted to evaluate the effect of keratinase (KE) on the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) in rice bran, cottonseed meal (CSM), rapeseed meal (RSM), corn distillers dried grains with solubles (DDGS), and peanut meal (PNM). Methods: Twelve crossbred barrows (Duroc×Landrace×Yorkshire, 50.5±1.4 kg body weight [BW]) fitted with T-cannulas at the terminal ileum were allotted to a 12×6 Youden Square design with 12 diets and 6 periods. The treatment diets included rice bran, CSM, RSM, corn DDGS, PNM, or corn-soybean meal (cSBM) supplemented with 0.05% KE or not. Diets were given to pigs at a level of 3% BW in two equal meals. The endogenous AA losses were the mean results of three previously experiments determined by a same nitrogen-free diet fed to pigs. Pigs had free access to water during the experiment. Results: The KE supplementation improved (p<0.05) the AID and SID of Met, Thr, Val, Asp, Cys, and Tyr in rice bran. Inclusion of KE increased (p<0.05) the AID and SID of Met and Val in CSM. The KE supplementation decreased (p<0.05) the AID and SID of His in RSM and all measured AA except for Arg, Met, Trp, Val, Gly, and Pro in corn DDGS. There was an increase (p<0.05) in AID and SID of Leu, Ile, Met, Ala, Cys, Ser, and Tyr in PNM supplemented with KE compared with that without KE. Inclusion of KE increased (p<0.05) the AID and SID of crude protein, Leu, Ile, Phe, Thr, Asp, and Ser in cSBM. Conclusion: This study indicated that KE had different effects on ileal AA digestibility of feedstuffs for growing pigs, which can give some usage directions of KE in swine feed containing those detected feedstuffs.

Error Accumulation and Transfer Effects of the Retrieved Aerosol Backscattering Coefficient Caused by Lidar Ratios

Houtong Liu,Zhenzhu Wang,Jianxin Zhao,Jianjun Ma 한국광학회 2018 Current Optics and Photonics Vol.2 No.2

The errors in retrieved aerosol backscattering coefficients due to different lidar ratios are analyzed quantitatively in this paper. The actual calculation shows that the inversion error of the aerosol backscattering coefficients using the Fernald backward-integration method increases with increasing inversion distance. The greater the error in the lidar ratio, the faster the error in the aerosol backscattering coefficient increases. For the same error in lidar ratio, the smaller actual aerosol backscattering coefficient will get the larger relative error of the retrieved aerosol backscattering coefficient. The errors in the lidar ratios for dust or the cirrus layer have great impact on the retrievals of backscattering coefficients. The interval between the retrieved height and the reference range is one of the important factors for the derived error in the aerosol backscattering coefficient, which is revealed quantitatively for the first time in this paper. The conclusions of this article can provide a basis for error estimation in retrieved backscattering coefficients of background aerosols, dust and cirrus layer. The errors in the lidar ratio of an aerosol layer influence the retrievals of backscattering coefficients for the aerosol layer below it.

The Nedd8-activating enzyme inhibitor MLN4924 suppresses colon cancer cell growth via triggering autophagy

Lv, Yongzhu,Li, Bing,Han, Kunna,Xiao, Yang,Yu, Xianjun,Ma, Yong,Jiao, Zhan,Gao, Jianjun The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.6

Neddylation is a post-translational protein modification process. MLN4924 is a newly discovered pharmaceutical neddylation inhibitor that suppresses cancer growth with several cancer types. In our study, we first investigated the effect of MLN4924 on colon cancer cells (HCT116 and HT29). MLN4924 significantly inhibited the neddylation of cullin-1 and colon cancer cell growth in a time and dose-dependent manner. MLN4924 induced G2/M cell cycle arrest and apoptosis in HCT116 and HT29 cells. Moreover, MLN4924 also triggered autophagy in HCT116 and HT29 cells via suppressing the PI3K/AKT/mTOR pathway. Inhibiting autophagy by autophagy inhibitor 3-MA or ATG5 knockdown reversed the function of MLN4924 in suppressing colon cancer cell growth and cell death. Interestingly, MLN4924 suppresses colon cell growth in a xenograft model. Together, our finding revealed that blocking neddylation is an attractive colon cancer therapy strategy, and autophagy might act as a novel anti-cancer mechanism for the treatment of colon cancer by MLN4924.

The Nedd8-activating enzyme inhibitor MLN4924 suppresses colon cancer cell growth via triggering autophagy

Yongzhu Lv,Bing Li,Kunna Han,Yang Xiao,Xianjun Yu,Yong Ma,Zhan Jiao,Jianjun Gao 대한생리학회-대한약리학회 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.6

Neddylation is a post-translational protein modification process. MLN4924 is a newly discovered pharmaceutical neddylation inhibitor that suppresses cancer growth with several cancer types. In our study, we first investigated the effect of MLN4924 on colon cancer cells (HCT116 and HT29). MLN4924 significantly inhibited the neddylation of cullin-1 and colon cancer cell growth in a time and dose-dependent manner. MLN4924 induced G2/M cell cycle arrest and apoptosis in HCT116 and HT29 cells. Moreover, MLN4924 also triggered autophagy in HCT116 and HT29 cells via suppressing the PI3K/AKT/mTOR pathway. Inhibiting autophagy by autophagy inhibitor 3-MA or ATG5 knockdown reversed the function of MLN4924 in suppressing colon cancer cell growth and cell death. Interestingly, MLN4924 suppresses colon cell growth in a xenograft model. Together, our finding revealed that blocking neddylation is an attractive colon cancer therapy strategy, and autophagy might act as a novel anti-cancer mechanism for the treatment of colon cancer by MLN4924.