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RISS 인기검색어
- 검색키워드
- 저자 : Qiang Joshua Li (검색결과 4 건)
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Automated Runway Groove Measurement and Evaluation
Lin Li,Kelvin C. P. Wang,Qiang Joshua Li,Wenting Luo 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.3
Grooves are frequently used on airport runways to address safety concerns by improving frictional properties and drainage capacity during wet weather. Groove performance deteriorates over time mostly due to traffic loading, accordingly periodic measurement and evaluation of groove dimensions are important for runway to maintain adequate frictional properties and avoid hydroplaning risks. However, such evaluation is difficult to perform due to lack of sufficient technologies to identify shallow and abrasive or worn grooves. This paper proposes new methodologies for automatic airport groove identification, measurement, and evaluation using high resolution texture data collected by point laser based profiling equipment developed by Federal Aviation Administration (FAA). Euler-Bernoulli beam filter and geometry contour based algorithms are developed to locate dips within a profile for potential groove identification. Subsequently improved moving average filter, forward and backward traversal methods are implemented to determine the starting and ending positions of each dip. Finally groove dimensions are computed per the FAA AC No. 150/5320-12C. The algorithm performance of the proposed method is evaluated based on Precision-Recall (PR) graphs with that of the FAA ProGroove software. Results indicate that the proposed methodology is more robust and accurate in runway groove identification. With the proposed method, operators of airfield runway pavements have a robust tool set to access groove performance and provide corrective maintenance actions.
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Wavelet based Macrotexture Analysis for Pavement Friction Prediction
Guangwei Yang,Qiang Joshua Li,You Jason Zhan,Kelvin C. P. Wang,Chaohui Wang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1
Pavement friction and texture characteristics are important aspects of road safety. Despite extensive studies conducted in the past decades, knowledge gaps still remain in understanding the relationship between pavement macrotexture and surface skid resistance. This paper implements discrete wavelet transform to decompose pavement surface macrotexture profile data into multi-scale characteristics and investigate their suitability for pavement friction prediction. Pavement macrotexture and friction data were both collected within the wheel-path from six High Friction Surface Treatment sites in Oklahoma using a high-speed profiler and a Grip Tester. The collected macrotexture profiles are decomposed into multiple wavelengths, and the total and relative energy components are calculated as indicators to represent macrotexture characteristics at various wavelengths. Correlation analysis is performed to examine the contribution of the energy indicators on pavement friction. The macrotexture energy within wavelengths from 0.97 mm to 3.86 mm contributes positively to pavement friction while that within wavelengths from 15.44 mm to 61.77 mm shows negative impacts. Subsequently, pavement friction prediction model is developed using multivariate linear regressive analysis incorporating the macrotexture energy indicators. Comparisons between predicted and monitored friction data demonstrates the robustness of the proposed friction prediction model.
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Laboratory and Field Performance Evaluation of Warm Mix Asphalt Incorporating RAP and RAS
Guangwei Yang,Kelvin Wang,Joshua Qiang Li,Matt Romero,Wenyao Liu 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.1
Pavement sustainability draws attention from different stakeholders in recent years. Warm mix asphalt (WMA) incorporating reclaimed asphalt pavement (RAP) or reclaimed asphalt shingles (RAS) has been widely recognized as a sustainable combo for pavement construction by conserving natural resources and reducing greenhouse gas emission. However, as their usage surges, little research has been conducted to date through a comprehensive laboratory and field evaluation to verify the performance of WMA incorporating RAP and RAS compared to traditional hot mix asphalt (HMA). In this research, five WMA sections with different WMA techniques and one control HMA section constructed in Oklahoma were continuously monitored for four years. The aggregate consensus, source, and gradation properties were tested in the laboratory. Mixture characteristics for lab-compacted samples including cracking resistance, rutting performance, moisture susceptibility, and water permeability were measured to compare WMA to HMA incorporating RAP and RAS. In addition, pavement surface conditions in terms of pavement cracking, rutting, roughness, texture, and friction were collected from the field site ten times in four years by using several state-of-the-art high-speed devices without traffic control. The laboratory and four-years field monitoring results demonstrate that WMA incorporating RAP and RAS accomplishes desired performance while providing sustainable benefits.
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( Miao Wang ),( Shao Hua Wang ),( Gong Li Zong ),( Zhong Wen Hou ),( Fei Liu ),( D Joshua Liao ),( Xi Qiang Zhu ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.2
Natamycin is a widely used antifungal antibiotic. For natamycin biosynthesis, the gene pimE encodes cholesterol oxidase, which acts as a signalling protein. To confirm the positive effect of the gene pimE on natamycin biosynthesis, an additional copy of the gene pimE was inserted into the genome of Streptomyces gilvosporeus 712 under the control of the ermE* promoter (permE*) using intergeneric conjugation. Overexpression of the target protein engendered 72% and 81% increases in the natamycin production and cell productivity, respectively, compared with the control strain. Further improvement in the antibiotic production was achieved in a 1 L fermenter to 7.0 g/l, which was a 153% improvement after 120 h cultivation. Exconjugants highly expressing pimE and pimM were constructed to investigate the effects of both genes on the increase of natamycin production. However, the co-effect of pimE and pimM did not enhance the antibiotic production obviously, compared with the exconjugants highly expressing pimE only. These results suggest not only a new application of cholesterol oxidase but also a useful strategy to genetically engineer natamycin production.
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