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Journal IOP Conference Series: Materials Science and Engineering

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M A Zarin, J S Tan, R Ahmad, N Z Jin, N F H A Aziz
IOP Conference Series: Materials Science and Engineering, Volume 716; doi:10.1088/1757-899x/716/1/012018

Abstract:Determination of inhibition of calcium oxalate (CaOx) crystallisation in vitro by nucleation assay is based on the rates of nucleation by comparing the slope of the turbidity of a control system with that of one exposed to the extract, which was found to be inaccurate when the CaOx crystals were formed and precipitated. A need exists for improved methods to determine the inhibition activity in nucleation assay for the study of anti-urolithiasis activity. In this study, the size reduction of CaOx crystals after treated with methanolic extract of Musa acuminate x balbisiana Colla cv. Pisang Awak Legor bagasse was measured under light microscopy and correlated to the turbidity and percentage of inhibition. Different concentrations of bagasse extract (2, 10, 30, 50 and 100 mg/ml) were investigated and the result shows that high concentration of extract would promote reduction in CaOx's stone size, but it increased the amount of sediment crystals, resulting high turbidity. The stone size was reduced up to 93.76±0.19% in the presence of 100 mg/mL extract while the inhibition percentage was negative (-102.17±0.04%) as the optical density (OD) of the extract was higher than control in the turbidity calculation. The results of this study are expected to provide an understanding on the way of calculating the activity in nucleation assay.
Zhiqiang Sun, Sciprofile linkShaohua Yin, Zhongbing Chen, Sciprofile linkJianlin Zhang, Sciprofile linkJianlu Shang, Sciprofile linkYishi Lv
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012008

Abstract:This paper put its eyes on the PWR's underwater components which have the risk of early failure after long-term inservice because the material tends to deteriorate and embrittle due to irradiation and other factors, and should be maintenanced. In this paper, we contrastively analyse two main technologies used as underwater welding, named underwater wet laser welding and underwater local dry laser welding. It is difficult to obtain high quality weld seam by underwater wet laser welding for the reason of some disadvantages on laser beam underwater, such as water attenuation, bubble reflection and so on. On constract, underwater local dry laser-welding can obtain high quality weld-joints, and becomes the current hotshot. But, there are still some problems to be settled, such as the way to obtain stable underwater chamber and the protection of back of full penetration weld. Analysis of the retrieva of underwater laser welding on Web Science, we can find that underwater laser welding technology has step out laboratory to engineering application and the in-depth theoretical research is also actively carried out on the fields of picosecond, femtosecond laser.
Sciprofile linkShihan Li, Xiaolin Wang, Wei Zhao, Zunzhao Li
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012026

Abstract:The microstructure and mechanical properties of two high strength steels with different carbon content were studied by means of metallographic microscope, scanning electron microscope, transmission electron microscope and mechanical testing machine. The results showed that the microstructure of the 0.2C (wt.%) steel and 0.4C (wt.%) steel was tempered sorbite, a large number of granular carbides dispersed on the ferritic matrix. The carbides contained Fe3C and M6C (Fe3Mo3C) phase. Compared with 0.2C steel, the content of the carbides of 0.4C steel was larger, while the particle size was smaller. The tensile and yield strength of 0.4C steel were higher, but the elongation was lower and the toughness was worse. In addition, the hardness values of the two materials were basically the same.
Jun Liu, Lu Hu, Yingqiu Song
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012053

Abstract:In the coastal atmospheric environment, corrosive media exists due to natural and man-made pollution, which has a great impact on the durability of concrete structures. Taking the environment of Shenzhen coastal salt spray area as an example, the environmental parameters were observed on site, and the content of carbon dioxide in the atmosphere was measured. The influence of steel corrosion on steel was analyzed. The study found that the annual temperature change range of the coastal salt spray area is 15 °C to 37.9 °C, and the change is first rising and then decreasing. The temperature rises in the first half of the year, and the temperature gradually decreases in the second half of the year. The highest humidity in the measurement area is 74.7%. The minimum is 56%, and the overall level is maintained at a high level, which is between 55% and 75%. The carbon dioxide content of the five measuring points is consistent throughout the year, and the carbon dioxide content is high in spring and winter.
Jie Wen, Yilin Wang, Guangru Sun, Shujing Liu, Weihua Zhang
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012050

Abstract:In our study, five stations of Poyang Lake were selected: Nanchang, Boyang, Jingde, Lushan and Jing'an. The three observational values of temperature, precipitation and evaporation in these five stations from 1988 to 2017 were analyzed. Through average, extreme value, linear regression and cumulative anomaly analysis, the interannual temperature variation trend of the five stations is consistent and is expected to continue to rise over the next 20 years; precipitation shows different changes in different periods; evaporation is decreasing year by year. This study is of great significance to the maintenance of ecological function and security of Poyang Lake.
Sciprofile linkJianguo Feng, Deshuai Ji, Zongjun Gao, Tongmin Lu, Minghao He
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012048

Abstract:Karst water resources is about 24% of the total amount of groundwater resources that can be exploited in China. Among the 15 groundwater sources in Tailai Basin, there are 12 karst water sources, accounting for 80%. With the survey and evaluation data of groundwater sources in Shandong Province, hydrochemical types analysis of karst water is carried out by Schukalev classification and The trilinear chart by Piper, and it is of great significance to development and utilization of karst water. The hydrochemical types of karst water is dominated by HCO3SO4-Ca water. However, if the naming of hydrochemical types involve nitrate, excess 39% of the karst water hydrochemical types changes. In addition, historical data shows that the concentration of nitrate in karst water has gradually increased, so it is recommended to increase nitrate indicators in the classification of hydrochemical types.
Chenghong Peng, Weiheng Zhu, Ling Chen, Xiaoke Zhu, Zhiling Chen
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012020

Abstract:This study analyzed the cause of fracture for the chain pin shaft of an escalator ladder, and found that the pin material satisfied the chemical composition content requirements of the GB 20CrMo steel standard and similar to ASTM A29/A29M-2012 grade 4120. Abnormal metallurgical quality defects were not found in the pin. The pin shaft was carburized, and internal oxidation defects were not observed on the surface as a result of carburization. The internal structure of the material was uneven, there existed a mixed grain structure, and the martensite structure was coarse at particular regions, to seven grade. Additionally, the martensite structure in the carburized layer was slightly coarser, four to five grade, which had an adverse effect on the pin strength. The pin break was a fatigue fracture caused by multiple cumulative damages. The fracture originated on the surface of the pin, and may have been caused by indentation on the pin's surface.
Yao Xu, Sciprofile linkShaohua Yin, Sciprofile linkChunpo Tang, Long Zhou
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012014

Abstract:In order to explore the cause of cracking of the main steam pipe of an ultra-supercritical unit, A series of corresponding physical and chemical tests for crack failure pipelines. Including chemical composition analysis, room temperature tensile test, high temperature tensile test, impact test, bending test of HAZ(Heat Affected Zone)and base metal, it's also including metallographic observation and section scanning electron microscopy analysis of crack tip, overall force analysis of pipeline, etc. The results show: Failure crack has obvious characteristics of crack type IV. for example, a large number of creep holes appear in the fine-grained region of the HAZ, Creep holes accumulate, grow up, and form microcracks. In addition, the stress analysis shows that the outer arc side of the pipe is subjected to large tensile stress. In conclusion, the pipe cracking failure is caused by the combination of tensile stress and type IV crack.
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012017

Abstract:Considering a finite time horizon crossing over multiple stages of a product life cycle, this study presents a genetic algorithm to deal with an economic order quantity model with multiple demand rates under a non-periodic policy. In real, the demand of the product life cycle is a non-linear function but we assumes it as four-segment linear or constant approximations in this work. In addition, a multiple-segment to be combined with linear or constant functions can be approximated a nonlinear function. This study does not focus on this, but it provides a genetic algorithm to deal with this proposed inventory problems. The particular of this research is that we develop a proposed replenishment scheme by the differentiating equation of the total cost with respect to replenishment time. Then, calculate the total cost of the proposed scheme as the fitness function to evaluate the populations. In this paper, an explicit procedure to obtain an approximating solution is provided and numerical examples to illustrate the proposed model are shown as well.
Sciprofile linkXiaojuan Cui, Zhirong Zhang, Tao Pang, Hua Xia, Pengshuai Sun, Bian Wu, Runqing Yu
IOP Conference Series: Materials Science and Engineering, Volume 730; doi:10.1088/1757-899x/730/1/012005

Abstract:A compact laser spectrometry instrument was developed for high precision measurements of isotope ratio of CO2 by tunable diode laser absorption spectroscopy in the mid-infrared at 2.7 μm. The experimental spectrum of carbon isotopologues in the gas phase near 3641 cm−1 is very suitable for real-time analysis of these isotopologues. Simultaneous measurements of the mixing ratio and the corresponding δ13C values of CO2 in the atmosphere were performed. The achieved standard deviation (1σ) of δ13C was 1.8‰. The Allan analysis of the time series of the mixing ratio of CO2 shows a measurement precision of 0.2‰ for δ13C with an optimum integration time of about 130 s. The spectrometer is capable of real-time measurements of stable carbon isotope ratios of CO2 under ambient conditions.
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