New Hanger Design Approach of Tied-Arch Bridge to Enhance Its Robustness

Wenqing Wu,Hao Wang,Yan-Jie Zhu,Jiangyu Yu,Hao Zhao,Hui Zhang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.11

As the crucial components among the tied-arch bridge, the local failure of hangers may trigger a progressive collapse through the entire tied-arch bridge. However, the current design guidance as regards hangers still lacks consideration of structure robustness under an extreme hazard. To improve the structural robustness of tied-arch bridge under extreme conditions, a new hanger design method is proposed, which is termed as asymmetric parallel double-hanger system. Based on Miner’s linear cumulative damage law, an analysis on the fatigue life of the double-hanger system was conducted to verify the feasibility of the proposal, and then a dynamic time-history analysis was employed to simulate the transitory fracture impact due to one or more hangers fracturing. According to the simulation results, the structural robustness is greatly enhanced with asymmetric parallel-double hanger system design, when compared with single hanger system design. When one or more hangers reveal local damage, it will not trigger a progress failure to the whole structure in particular. Several practical suggestions of bridge system’s load-carrying capacity are also put forward for the future arch bridge design at the end of this paper.

Detection of reactive oxygen species generated by microwave electrodeless discharge lamp and application in photodegradation of H2S

Jiang Yu,Yang Yu,Tingting Zhang,Liqiong Zheng 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.7

The photodegradation of hydrogen sulfide (H2S) was examined using a self-made microwave electrodeless discharge lamp (MEDL). The features of the MEDL had been tested. The results showed that the MEDL absorbed 18.3, 32.7 and 41.8W power at the microwave (MW) output power of 165, 330 and 660W, respectively. The intensity of the emitted light increased with increasing MW output power. The reactive oxygen species (ROS) generated by irradiated air and nitrogen were detected, respectively. It was illustrated that the irradiated air could generate a number of ROS, at least including 1O2 and •OH. And the amount of ROS increased with increasing MW output power. In photodegradation of H2S process, the effects of MW output power and gas composition were investigated. The removal efficiency of H2S under nitrogen was obviously lower compared with that under air. The removal efficiency of H2S increased with increasing MW output power.

GROWTH OF Chlamydomonas reinhardtii AND ITS NUTRIENT UPTAKE UNDER DIFFERENT NITROGEN AND PHOSPHORUS LEVELS

Jiang Yu,Ziyi Su,Ci Wang 한국수산과학회 양식분과 2015 한국수산과학회 양식분과 학술대회 Vol.2015 No.5

Simulation of non-Gaussian stochastic processes by amplitude modulation and phase reconstruction

Jiang, Yu,Tao, Junyong,Wang, Dezhi Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.18 No.6

Stochastic processes are used to represent phenomena in many diverse fields. Numerical simulation method is widely applied for the solution to stochastic problems of complex structures when alternative analytical methods are not applicable. In some practical applications the stochastic processes show non-Gaussian properties. When the stochastic processes deviate significantly from Gaussian, techniques for their accurate simulation must be available. The various existing simulation methods of non-Gaussian stochastic processes generally can only simulate super-Gaussian stochastic processes with the high-peak characteristics. And these methodologies are usually complicated and time consuming, not sufficiently intuitive. By revealing the inherent coupling effect of the phase and amplitude part of discrete Fourier representation of random time series on the non-Gaussian features (such as skewness and kurtosis) through theoretical analysis and simulation experiments, this paper presents a novel approach for the simulation of non-Gaussian stochastic processes with the prescribed amplitude probability density function (PDF) and power spectral density (PSD) by amplitude modulation and phase reconstruction. As compared to previous spectral representation method using phase modulation to obtain a non-Gaussian amplitude distribution, this non-Gaussian phase reconstruction strategy is more straightforward and efficient, capable of simulating both super-Gaussian and sub-Gaussian stochastic processes. Another attractive feature of the method is that the whole process can be implemented efficiently using the Fast Fourier Transform. Cases studies demonstrate the efficiency and accuracy of the proposed algorithm.

Densification, Microstructural, and Mechanical Properties of Al-Mn-Mg-Er-Zr Alloy Fabricated by Laser Powder Bed Fusion

Jiang Yu,Yaoxiang Geng,Zhijie Zhang,Hongbo Ju 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11

To address the high cost of raw materials for laser powder bed fusion (L-PBF) processed high-performance Al-Mn-Mg-Sc-Zr alloy, a novel Er- and Zr-modified Al-Mn-Mg alloy was fabricated by L-PBF using pre-alloyed powder in this study. The large internal stress and the existence of the keyhole together caused cracks in most of the L-PBF processed samples. The as-built sample exhibited a heterogeneous grain structure, including main columnar α-Al grains in the inner region ofthe molten pool and a few ultrafine α-Al equiaxed grains at the fusion boundary. Al3Ernanoparticles were attached to theAl6Mnphase, and both mainly precipitated at the grain boundary of α-Al. The existence of Mn in the alloy reduced thegrain refining effect of Er elements. The yield strength (YS), ultimate tensile strength (UTS) and elongation of the as-builtalloy were 327 ± 5 MPa, 502 ± 3 MPa, and 12.2 ± 1% respectively. When the aging temperature was over 350 ℃, the primaryprecipitates in the sample grew up, and needle-shaped secondary Al6Mnnanoparticles precipitated from α-Al. 350 ℃-6 haging alloy exhibited maximum Vickers hardness of 171 ± 1 HV with YS, UTS and elongation of 339 ± 2 MPa, 508 ± 1 MPaand 8.1 ± 1%, respectively. During the tensile process of the alloy, micro-cracks mainly originated from the fusion boundary. At last, the authors also shared some prospects for future work.

Recognition and Positioning Method of Rice Seedlings Based on Machine Vision

Jiang Yu,Cui Hongwei,Qi Long,Zheng Wenhan,Zhao Liulin 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.9

Enhancing the Photovoltaic Performance of Polymer Solar Cells by Manipulating Photoactive/Metal Interface

Jiang, Yu,Sai-Anand, Gopalan,Xu, Binrui,Lee, Jae-Sung,Kim, Sae-Wan,Yeom, Se-Hyuk,Bae, Jin-Hyuk,Kang, Shin-Won American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.11

<P>In this work, a hybrid system composed of inorganic zinc oxide nanocrystals (ZnO NCs) and the organic conjugated polymer (poly[(9,9-bis(3'-(N, N-dimethylamino) propyl)-2,7-fluorene)-alt-2,7-( 9,9-dioctylfluorene)]) (PFN) was utilized as an electron selective interlayer (ESIL) to improve the electro-optical characteristics of bulk-heterojunction (BHJ) polymer solar cells (PSCs). To accomplish, water/alcohol-soluble cationic polyelectrolyte, PFN, was introduced into ZnO NCs (ZnO-PFN), aiming to enhance the electron extraction capability between the photoactive layer and the metal (Al) electrode in standard geometry BHJ PSCs. Importantly, the ZnO-PFN blend system achieved a higher power conversion efficiency (PCE) than pristine (ZnO NCs) ESILs. Moreover, an optimized photovoltaic (PV) performance was obtained with a low volume of PFN incorporated into the ZnO NCs ESIL. To validate the PV performance, PSCs were fabricated based on co-polymer of thienyl substituted BDT with TT:phenyl-C71-butyric acid methyl ester (PBDTTT-C-T:PC71BM) and poly(3-hexylthiophene-2,5-diyl): phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) photoactive systems and observed superior PV characteristics for ZnO-PFN hybrid ESILs. The optical transparency, microstructure, and morphological characteristics were evaluated using appropriate characterization techniques to demonstrate the superiority of the hybrid ZnO-PFN blend system. PSCs based on this ZnO-PFN composite based ESIL suggested an alternative practical approach to enhance the efficiency of the fabricated devices.</P>