Evaluation and Prediction on the Hydraulic Abrasion Performance of High Belite Cement-Based Concrete

Chunmeng Jiang,Linhua Jiang,Cheng Chen,Jingwei Gong,Shuangxi Li 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.6

High belite cement (HBC) concrete is increasingly applied to the hydraulic projects, where much attention should be paid to the abrasion performance. In this paper, the mass loss, abrasion rate and morphology indexes such as depth of abrasion, volume loss and fractal dimension of HBC-based concrete at different wear periods were determined through underwater method. Moreover, a new method by transforming the survey area of worn surface was put forward to simulating practical erosion conditions, based on which, the abrasion performance prediction model was built by Projection Pursuit Regression (PPR) theory. Results show that the compounding addition of 30% mineral admixtures had little contribution to the abrasion resistance of HBC concrete after being long-term cured, while reducing water-binder (w/b) ratios was still an effective way for improving that. The worn surface of concrete specimens was divided into three regions for abrade zone, transitional zone and sound zone, and the abrasion evolution was found to be related to the wear duration and space position. Furthermore, there were good correlations between mass loss rate, depth of abrasion, volume loss and fractal dimension, and the fitting formulas were also proposed with good coefficients. Eventually, the PPR model based on the data of transformed survey area was proved to be a promising approach for predicting the abrasion performance.

Experimental research and molecular dynamics simulation on thermal properties of capric acid/ethylene-vinyl/graphene composite phase change materials

Yue Gu,Linhua Jiang,Weizhun Jin,Zhenhua Wei,Xing Liu,Mingzhi Guo,Kailun Xia,Lei Chen 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

In this paper, a new series of phase change materials (PCMs) composed of capric acid/ethylene-vinylacetate/graphene (CA/EVA/GR) were prepared and thermal properties were investigated using moleculardynamics simulation. The composite PCMs were characterized by Fourier transform infraredspectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanningcalorimetry (DSC) and thermal conductivity measurement. FT-IR, XRD and SEM results manifest that CAcan be successfully wrapped by EVA and GR additives, and there is no chemical reaction between CA, EVAand GR. DSC results indicate that adding GR into CA/EVA can result in composite PCMs maintain the highlatent heat, while too much GR will cause a significant reduction in latent heat. Thermal conductivityobtained from experimental tests reveal that GR can gradually enhance the thermal conductivity of CA/EVA with increasing dosage of GR. The experimental results of thermal conductivity fall close to that ofmolecular dynamics (MD) simulation at GR dosages below 1.8 wt%, but the experimental results present atrend which is contrary to MD simulation at higher GR dosages. The mean square displacement (MSD)results manifest that composite PCMs containing 1.8 wt% GR has the highest diffusion coefficient, whilehigher GR dosage will reduce the diffusion coefficient gradually.

Modeling of damage in cement paste subject to external sulfate attack

Chuansheng Xiong,Linhua Jiang,Yan Zhang,Hongqiang Chu 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.16 No.6

This study aimed to develop models of sulfate diffusion and ettringite content profile in cement paste for the predication of the damage behavior in cement paste subject to external sulfate. In the models, multiphase reaction equilibrium between ions in pore solution and solid calcium aluminates phases and the microstructure changes in different positions of cement paste were taken into account. The distributions of expansive volume strain and expansion stress in cement paste were calculated based on the ettringite content profile model. In addition, more sulfate diffusion tests and SEM analyses were determined to verify the reliability and veracity of the models. As the results shown, there was a good correlation between the numerical simulation results and experimental evidences. The results indicated that the water to cement ratio (w/c) had a significant influence on the diffusion of sulfate ions, ettringite concentration profile and expansion properties in cement paste specimens. The cracking points caused by ettringite growth in cement paste specimens were predicted through numerical methods. According to the simulation results, the fracture of cement paste would be accelerated when the specimens were prepared with higher w/c or when they were exposed to sulfate solution with higher concentration.

Chloride diffusion in concrete associated with single, dual and multi cation types

Zijian Song,Linhua Jiang,Ziming Zhang 사단법인 한국계산역학회 2016 Computers and Concrete, An International Journal Vol.17 No.1

Currently, most of the investigations on chloride diffusion were based on the experiments and simulations concerning single cation type chlorides. Chloride diffusion associated with dual or multi cation types was rarely studied. In this paper, several groups of diffusion experiments are conducted using chloride solutions containing single, dual and multi cation types. A multi-ionic model is also proposed to simulate the chloride diffusion behavior in the experimental tests. The MATLAB software is used to numerically solve the nonlinear PDEs in the multi-ionic model. The experimental and simulated results show that the chloride diffusion behavior associated with different cation types is significantly different. When the single cation type chlorides are adopted, it is found that the bound rates of chloride ions combined with divalent cations are greater than those combined with monovalent cations. When the dual/multi cation type chlorides are adopted, the chloride bound rates increase with the Ca2+/Mg2+ percentage in the source solutions. This evidence indicates that the divalent cations would markedly enhance the chloride binding capacity and reduce the chloride diffusivity. Moreover, on the basis of the analysis, it is also found that the complicated cation types in source solutions are beneficial to reducing the chloride diffusivity.

Newly Discovered z ~ 5 Quasars Based on Deep Learning and Bayesian Information Criterion

신수현,임명신,김용정,Linhua Jiang 한국천문학회 2022 Journal of The Korean Astronomical Society Vol.55 No.4

We report the discovery of four quasars with $M_{1450} \gtrsim -25.0$ mag at z ~ 5 and supermassive black hole mass measurement for one of the quasars. They were selected as promising high-redshift quasar candidates via deep learning and Bayesian information criterion, which are expected to be effective in discriminating quasars from the late-type stars and high-redshift galaxies. The candidates were observed by the Double Spectrograph on the Palomar 200-inch Hale Telescope. They show clear Ly$\alpha$ breaks at about 7000--8000 \AA, indicating they are quasars at $4.7 < z < 5.6$. For HSC J233107-001014, we measure the mass of its supermassive black hole (SMBH) using its C IV $\lambda 1549$ emission line. The SMBH mass and Eddington ratio of the quasar are found to be ~10$^8 M_{\odot}$ and ~0.6, respectively. This suggests that this quasar possibly harbors a fast growing SMBH near the Eddington limit despite its faintness ($L_{\rm Bol} < 10^{46} $erg\,s$^{-1}$). Our 100\% quasar identification rate supports high efficiency of our deep learning and Bayesian information criterion selection method, which can be applied to future surveys to increase high-redshift quasar sample.

Reevaluating the overhead of data preparation for asymmetric multicore system on graphics processing

( Songwen Pei ),( Junge Zhang ),( Linhua Jiang ),( Myoung-seo Kim ),( Jean-luc Gaudiot ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.7

As processor design has been transiting from homogeneous multicore processor to heterogeneous multicore processor, traditional Amdahl`s law cannot meet the new challenges for asymmetric multicore system. In order to further investigate the impact factors related to the Overhead of Data Preparation (ODP) for Asymmetric multicore systems, we evaluate an asymmetric multicore system built with CPU-GPU by measuring the overheads of memory transfer, computing kernel, cache missing and synchronization. This paper demonstrates that decreasing the overhead of data preparation is a promising approach to improve the whole performance of heterogeneous system.

Performance of corrosion inhibitor extracted from enzymatic hydrolysate of waste Platanus acerifolia leaves

Zijian Song,Huanchun Cai,Qingyang Liu,Linhua Jiang,Hongqiang Chu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-

In this study, an ultrasound-assisted enzymatic extraction (UEE) method was proposed to augment theanti-corrosion performance of the green inhibitor extracted from waste Platanus acerifolia leaves. Chemical compositions and anticorrosive properties of UEE extract were characterized via multiple technologies. The adsorption film on the steel surface was characterized via X-ray photoelectron spectroscopy(XPS). The surface information of corroded steel was also analyzed. Results showed that, compared withthe ultrasound-assisted alkali extraction (UAE), UEE increased the utilization rate of raw plant materialsby 22%39%. After optimized via response surface methodology, the maximum yield of UEE extract couldreach 27.081 mg/g. Electrochemical results showed, compared with 3% UAE extract, the inhibition efficiencyof 3% UEE extract after 72 h in 0.5 M NaCl was increased by 22% while the extraction time wassaved by 90%. Microscopic observations also proved that UEE extract can effectively mitigate the corrosiondegree where the roughness of steel surface decreased by 63.67%. XPS results revealed that a carbonaceousprotecting layer was formed on steel surfaces. The inhibition mechanism analysis suggestedthat flavonoids and their derivatives were apt to adsorb on the steel surface via chelation and surfacephysical adsorption, which could block the pathway of chloride attack.

A state-of-the-art review of self-healing stimuli-responsive microcapsules in cementitious materials

Zilang Huang,Zijian Song,Yunsheng Zhang,Saddick Donkor,Linhua Jiang,Hongqiang Chu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

Cracking is a recurring defect that typically arises during the construction and service periods of cementitiousmaterials. Self-healing based on stimuli-responsive microcapsules has shown to be a cutting-edgetechnology to make cementitious materials sustainable. Despite the reported implementation of microcapsulesin various fields, the strategies toward self-healing of cementitious materials via embeddingmicrocapsules remain a significant challenge. Given this, a review concentrating on the healing explorationof cementitious materials assisted by self-healing stimuli-responsive microcapsules is conductedto bridge the gap. Special attention is given to the encapsulation designs and preparation processes, followedby capsules’ response mechanisms and healing processes. In particular, application scenarios, challengesand future prospects of self-healing stimuli-responsive microcapsules for cementitious materialsare summarized and proposed in detail for the first time. This review attempts to better grasp the futureresearch direction of this field, which provides new perspectives for addressing the cracking issue ofcementitious materials.

The Infrared Medium-deep Survey. IX. Discovery of Two New z ~ 6 Quasars and Space Density down to M1450 ~ -23.5 mag

Yongjung Kim,Myungshin Im,Yiseul Jeon,Minjin Kim,Linhua Jiang,Suhyun Shin 한국천문학회 2022 天文學會報 Vol.47 No.1

TiO 2 SUB-MICROSPHERES AS A BI-FUNCTIONAL SCATTERING LAYER FOR HIGH- PERFORMANCE DYE-SENSITIZED SOLAR CELLS

YONG DING,SONGYUAN DAI,Litao Jia,YANMEI MA,ZHAOQIAN LI,CHANGNENG ZHANG,JIANXI YAO,LIE MO,LINHUA HU,BING ZHANG,LING JIANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.5

The sub-microspheres play multiple roles in enhancing dye adsorption and light-scattering toimprove the performance of dye-sensitized solar cells (DSSCs). In this work, the well-de¯ned TiO 2sub-microspheres with anatase granular-like nanocrystals are prepared in high yield by com-bining hydrolytic process with solvothermal treatment. Scanning electron microscopy (SEM) andtransmission electron microscopy (TEM) results indicated that plenty of rhombic nanoparticleswith ? 18 nm diameter having mutual contacts to neighboring nanoparticles were densely self-assembled into sub-microspheres, and abundant mesopores existed in the whole sub-microsphereswith superior light scattering ability. The appropriate pore diameter and relatively high speci¯csurface area of the as-obtained sub-microsphere result in a higher dye adsorption. As expected, byusing the sub-microspheres as a scattering layer, a higher photovoltaic conversion e±ciency of10.15% is obtained for DSSCs.