Post-fire Study on Mechanical Properties of Damaged Ultra-high Strength Concrete

Xiao Lyu,Guang-Hao Jia,Gan-Ping Shu,Xin Zhang,Er-Feng Du,Wen-Ming Wang 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.6

In order to study the eff ect of steel tube, pre-load and temperature on residual performance of heated ultra-high strength concrete (UHSC), an experimental program was carried out to investigate the physical and mechanical properties of UHSC post-fi re in room temperature. With total of 54 standard cylindrical concrete specimens subjected to various temperatures ranging from 62 °C to 496 °C, their residual compressive strength, elastic modulus, peak strain was measured after natural cooling down. By comparing the test results of standard cylindrical concrete specimens with the results of the bare specimens in and after fi re, it is known that the residual compressive strength of standard cylindrical concrete specimens decayed more serious after exposing to same temperature. Seen from the results, the temperature which the specimens suff ered was found to be responsibility to the reduction of the compressive strength, elastic modulus, peak strain. As the temperature up to 300 °C, the strength reduction coeffi cient of UHSC was 0.67 ~ 0.68 and the elastic modulus reduction coeffi cient of UHSC was 0.41 ~ 0.51 with peak strain coeffi cient ε cr ( T ) /ε 0 1.57 ~ 1.67. Finally, based on the analysis of test results, simple formulae were proposed to describe the eff ect of temperature on residual performance of heated UHSC which infi lled the steel tube.

Parameters Effect on Predicting Fire Resistance of Ultra-high Strength Concrete Filled Protected Square Steel Tubular Columns

Xiao Lyu,Gan-Ping Shu,Er-Feng Du 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.5

Ultra-high strength concrete (UHSC) with compressive strength greater than 100 MPa at room temperature has been developed for concrete fi lled square steel tubular column for use in high-rise buildings. The fi re resistance of UHSC fi lled protected square steel tubular columns exposed to the standard ISO fi re is investigated in this paper. For this purpose, numerical heat transfer analysis and nonlinear thermal stress analysis were conducted by taking into account the existing material properties, such as the thermal and mechanical properties of UHSC and high strength steel. The numerical analyses were carried out and the results were validated against the test results in terms of heat distribution and mechanical behavior. Comparison with the test results showed a reasonable agreement with fi nite element results in terms of temperature fi eld prediction and load displacement behavior during the fi re. Finally, based on the validated fi nite element model, the eff ects of fi re protection thickness, load ratio, the strengths of concrete and steel, steel contribution ratio, and relative slenderness ratio on the fi re resistance of UHSC fi lled square steel tubular columns were carried out and discussed.

Implementation of design of experiment for structural optimization of annular jet pumps

Qiao Lyu,Zhihuai Xiao,Qinlong Zeng,Longzhou Xiao,Xinping LONG 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.2

The DOE (Design of experiments) method together with CFD (Computational fluid dynamics) was applied to optimize structural combination of the Annular jet pumps (AJPs). An AJP with an area ratio of 1.75 was selected as the simulation prototype and the numerical results were validated by experiments. According to the DOE method, four impact factors were selected for simulation. The results showed that two-factor’s reciprocal action is more applicable than that of single factor on the AJP’s performance, especially the two groups ,α*l t and l t *β, respectively. The structure of AJPs with different area ratios ranging from 1.5 to 40 were optimized by the DOE method. The corresponding optimum structural parameters and performance curves were plotted to acquire the performance envelope lines, the efficiency envelope line and the peak efficiency lines, which are useful for AJP’s structure design and obtaining its operation condition.

Numerical study of shock/vortex interaction in diatomic gas flows

Xiao, H.,Tang, K.,Xu, Z. Z.,Li, D. y.,Lyu, S. K. Springer Science + Business Media 2016 International Journal of Precision Engineering and Vol.17 No.1

<P>The particle-based direct simulation of Monte Carlo(DSMC) was present and validated for the investigation of non-equilibrium effects in diatomic gas flows. All the validations show that the results of the present DSMC is in agreement with the experimental data. Then, the numerical studies of micro scale shock/composite-vortex interactions in diatomic gas flows were conducted The substantial attenuation of enstrophy in diatomic gas flow is observed Differ from the sharp decreasing in diatomic gas, the time evolution of enstrophy in monatomic gas flow decrease linearly in the whole process. This study also shows that the vortex deformation through a shock, in particular, is observed to be strongly dependent on the shock and vortex strengths. Also, it is also found that strong interaction can also cause voracity production in microscale shock/vortex interaction for diatomic gas flow The attenuation, analogous to DSMC results, overwhelms the vorticity generation only in a limited set of regimes with low shock Mach number; small vortex size, or weak vortex. Besides, in diatomic gas flow, viscous voracity generation is also most dominant in the three dynamical processes of voracity transportation, followed by dilatational and baroclinicvorticity generation. The present study conform that shock/vortex present different features in strong and weak interactions for monatomic and diatomic gas flows. Furthermore, it provides a new way for the investigation of non-equilibrium effects.</P>

Coloration and Decoloration of Textiles Using a TiO2 Composite Pigment

Xiao Wang,Yunzhe Xie,Cheng Huang,Yongzhu Cui,Lihua Lyu,Yuping Zhao,Ju Wei 한국섬유공학회 2018 Fibers and polymers Vol.19 No.7

A colorable pigment was prepared by dye adsorption onto titanium dioxide and subsequent silane coating. The effects of pH value, dye concentration, and adsorption times on dye adsorption were discussed. Large adsorption capacity of an anionic dye was obtained at pH value of 2 and the adsorption process was well described by the Langmuir isotherm model. Good dyeability and color fastness of pigment dyed fabric were achieved in the normal life cycle under sunlight. The decoloration of pigment was realized through photocatalytic degradation of dye molecules by titanium dioxide under ultraviolet irradiation when reusing the pigment dyed textiles after disposal. The new absorption peaks in the FTIR spectrum at 2924.95 cm-1, 1714.91 cm-1, 1461.17 cm-1, and 1289 cm-1 verified silane modification. Silane modification improved fixation of dyes onto the pigment and immobilization of pigments onto substrates. The close attachment of silane coating layer to titanium dioxide was conducive to photodegradation of dye molecules in the pigment.

Synthesis and Properties of Thioether-containing Aliphatic Polyesters

Xiao-Wei Kan,An Lyu,Qi-Yuan Wang,Ling-Gao Li,Zi-Chen Li 한국고분자학회 2018 한국고분자학회 학술대회 연구논문 초록집 Vol.43 No.2

Experimental Research on a Hypersonic Configuration with Blunt Forebody Edges

Xiao, Hong,Xu, Zhe-Zhu,Kim, Lae-Sung,Li, Dong-yang,Lyu, Sung-Ki Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.10

A design method, for hypersonic forebody configuration with blunt edges, was developed by lift body and waverider. Experimental study was conducted. It was showed that the difference of pressure coefficient, at centre-line and side-line on forebody pre-compression surface, was between 2.5% and 16.7% within the Mach number 5 to 7 and attack angle 0 to 12. These differences were slightly bigger than those of non-blunt-edges forebody. However, experimental data also show that the present configuration can achieve the closed shockwave, and can also realize the automatic overflow of boundary layer on forebody pre-compression surface. It is also observed that the present forebody gets a good aerodynamic performance at high Mach numbers. But with increasing attack angle, the advantage was weakened gradually. And, at the degree of side-slip exceeding 8, the side-line pressure is higher than that of center-line, which indicates that the forebody boundary layer does not achiev automatically overflowing to side surface.

Leaky-Wave Antennas Based on Noncutoff Substrate Integrated Waveguide Supporting Beam Scanning From Backward to Forward

Yue-Long Lyu,Xiao-Xin Liu,Peng-Yuan Wang,Erni, Daniel,Qun Wu,Cong Wang,Nam-Young Kim,Fan-Yi Meng Institute of Electrical and Electronics Engineers 2016 IEEE transactions on antennas and propagation Vol.64 No.6

<P>In this paper, we propose an approach to realize substrate integrated waveguide (SIW)-based leaky-wave antennas (LWAs) supporting continuous beam scanning from backward to forward above the cutoff frequency. First, through phase delay analysis, it was found that SIWs with straight transverse slots support backward and forward radiation of the -1-order mode with an open-stopband (OSB) in between. Subsequently, by introducing additional longitudinal slots as parallel components, the OSB can be suppressed, leading to continuous beam scanning at least from -40 degrees through broadside to 35 degrees. The proposed method only requires a planar structure and obtains less dispersive beam scanning compared with a composite right/left-handed (CRLH) LWA. Both simulations and measurements verify the intended beam scanning operation while verifying the underlying theory.</P>

A Study on Improvement of Ball Screw System Positioning Error with Liquid-Cooling

Xu, Zhe-Zhu,Liu, Xiao-Jing,Choi, Chong-Hun,Lyu, Sung-Ki 한국정밀공학회 2012 International Journal of Precision Engineering and Vol.13 No.12

The demand for higher productivity and tight part tolerances requires machine tools to have faster and more accurate feed drive systems. As tried and tested technology, ball screw drive systems are still used in a majority of machine tools due to their low cost and high degree of stiffness. A high-speed ball screw drive system generates more heat and results in greater positioning error, adversely affecting the accuracy of machined parts. In this paper, we discuss the placement of a liquid-cooling system using water, coolant oil, light oil and cutting oil as coolants in a ball screw shaft to avoid thermal errors and achieve temperature equilibrium faster. In order to estimate the positioning error and thermal distribution of the ball system and effectiveness of the liquid-cooling system, all possible heat gain-loss sources were analyzed and considered calculation factors. The following paper also presents degree of positioning error improvement when a circulation liquid-cooling system and forced liquid-cooling system were employed. When comparing the predictions and the experimental results, we can see very significant cooling performance and a high degree of consistency between prediction and reality.

Phylogenetic and expression analysis of the angiopoietin-like gene family and their role in lipid metabolism in pigs

Zibin Zheng,Wentao Lyu,Qihua Hong,Hua Yang,Ying Li,Shengjun Zhao,Ying Ren,Yingping Xiao Asian Australasian Association of Animal Productio 2023 Animal Bioscience Vol.36 No.10

Objective: The objective of this study was to investigate the phylogenetic and expression analysis of the angiopoietin-like (ANGPTL) gene family and their role in lipid metabolism in pigs. Methods: In this study, the amino acid sequence analysis, phylogenetic analysis, and chromosome adjacent gene analysis were performed to identify the ANGPTL gene family in pigs. According to the body weight data from 60 Jinhua pigs, different tissues of 6 pigs with average body weight were used to determine the expression profile of ANGPTL1-8. The ileum, subcutaneous fat, and liver of 8 pigs with distinct fatness were selected to analyze the gene expression of ANGPTL3, ANGPTL4, and ANGPTL8. Results: The sequence length of ANGPTLs in pigs was between 1,186 and 1,991 bp, and the pig ANGPTL family members shared common features with human homologous genes, including the high similarity of the amino acid sequence and chromosome flanking genes. Amino acid sequence analysis showed that ANGPTL1-7 had a highly conserved domain except for ANGPTL8. Phylogenetic analysis showed that each ANGPTL homologous gene shared a common origin. Quantitative reverse-transcription polymerase chain reaction analysis showed that ANGPTL family members had different expression patterns in different tissues. ANGPTL3 and ANGPTL8 were mainly expressed in the liver, while ANGPTL4 was expressed in many other tissues, such as the intestine and subcutaneous fat. The expression levels of ANGPTL3 in the liver and ANGPTL4 in the liver, intestine and subcutaneous fat of Jinhua pigs with low propensity for adipogenesis were significantly higher than those of high propensity for adipogenesis. Conclusion: These results increase our knowledge about the biological role of the ANGPTL family in this important economic species, it will also help to better understand the role of ANGPTL3, ANGPTL4, and ANGPTL8 in lipid metabolism of pigs, and provide innovative ideas for developing strategies to improve meat quality of pigs.