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1
Strobl, Susanne, Roland Haubner und Wolfgang Scheiblechner. „New Steel Combinations Produced by the Damascus Technique“. Advanced Engineering Forum 27 (April 2018): 14–21. http://dx.doi.org/10.4028/www.scientific.net/aef.27.14.
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Multilayered forged steel plates, which combine the properties of diverse steel qualities, are referred to as Damascus steels. Since the 3rd century AD blades and weapons have been produced by the Damascus technique in Europe. In this work four different steel combinations were investigated. Combining Fe with carbon steel C60 resulted in a ferritic-pearlitic microstructure. By forging two heat-treatable steels C40 and C60 martensite with an inhomogeneous carbon distribution was formed. Combining Fe with an austenitic stainless steel showed ferrite and austenite with grain boundary carbides and segregation bands. The last combination of two cold working steels K110 and K600 led to a complex microstructure with martensite, retained austenite and two special types of carbides. After metallographic preparation and using of different etchants the various microstructures were characterized by light optical microscopy and confirmed by Vicker ́s microhardness measurements. Of high interest are the interfaces and the quality of the weld between the individual steel layers. In some regions oxidation and carbon diffusion were observed.
2
Xiao, Liang Li, Xiao Yu und Jian Wei Han. „Analysis on Axial Compression Bearing Capacity of Steel Reinforced Concrete Sandwich Node“. Applied Mechanics and Materials 501-504 (Januar 2014): 685–89. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.685.
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According to the limit values of axial compression ratio of steel reinforced concrete given by technical specification for steel reinforced concrete composite structure (JGJ138-2001), the axial force of steel reinforced concrete sandwich nodes calculated by MIDAS and the axial bearing capacity calculated by limit values of axial compression ratio are compared with an actual project. The results show that steel concrete columns with designed strength of C60, the strength more than of column concrete strength higher than C50 is the least requirement as to meet the axial compression ratio. The result provides a theoretical basis for the future of safety work and the sandwich joint construction.
3
Zheng, Yuanxun, Xiaolong Wu, Guangxian He, Qingfang Shang, Jianguo Xu und Yikai Sun. „Mechanical Properties of Steel Fiber-Reinforced Concrete by Vibratory Mixing Technology“. Advances in Civil Engineering 2018 (12.07.2018): 1–11. http://dx.doi.org/10.1155/2018/9025715.
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As a kind of important engineering material, steel fiber-reinforced concrete was used widely in civil engineering. Up to now, steel fiber-reinforced concrete was usually produced by the traditional mixing method. For the reason of uniform distribution of fiber, the reinforcement of mechanical properties of concrete was inadequately performed. In this paper, C50 steel fiber-reinforced concrete and C60 steel fiber-reinforced concrete were manufactured by traditional mixing and vibratory mixing methods, respectively, and then, the cube compression test, flexural test, splitting tensile test, and the bending test were carried out. The reinforcement effects of mechanical properties were analyzed by comparing the traditional mixing and vibratory mixing methods. The results show that vibratory mixing can effectively improve the distribution of steel fibers in concrete and can increase the density of steel fiber concrete, and therefore, it effectively improves the mechanical properties of steel fiber-reinforced concrete when compared to the traditional mixing method.
4
Li, Fang Hua. „Performance Test of C60 Self-Compacting Steel Fiber Concrete“. Key Engineering Materials 871 (Januar 2021): 330–39. http://dx.doi.org/10.4028/www.scientific.net/kem.871.330.
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Self-compacting steel fiber concrete must meet the strength standard after steel fiber is added and must have good fluidity. The test results show that the addition of steel fiber to concrete will affect the fluidity of concrete. Compared with ordinary concrete, the addition of steel fiber will improve the compressive strength and flexural tensile strength of concrete to varying degrees. The mix proportion test can be carried out in stages, i.e. the mix proportion meeting all performance indexes used is determined first, then steel fiber is added and adjusted to determine the best mix proportion.
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Zhao, Wei, Jinke Tang, Ashok Puri, Ray L. Sweany, Yuxin Li und Liquan Chen. „Tribological properties of fullerenes C60 and C70 microparticles“. Journal of Materials Research 11, Nr. 11 (November 1996): 2749–56. http://dx.doi.org/10.1557/jmr.1996.0349.
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The frictional behaviors of fullerenes C60 and C70 were studied because they were speculated to be solid lubricants. For the sublimated pure C60 films on Si(001), a high friction coefficient (0.55–0.8) was observed under different loads and pin materials. For the C70 film, the friction coefficient showed a pin dependence, which changed from 0.5 with an Al2O3 pin to about 0.9 with a 440 stainless steel pin. The relatively high friction coefficients of C60 and C70 films were due to the tendency of the C60 and C70 particles to clump and compress into high shear strength layers rather than due to the impurities in the fullerenes. The benzene-solvated C60 · 4C6H6 and C70 ·xC6H6 showed a lowered friction coefficient (0.25 for C60 · 4C6H6 and 0.3 for C70 · xC6H6), which might result from the lowered shear strength of the hcp structure of C60 · 4C6H6 and C70 ·xC6H6 molecular crystals in which the benzene molecules were intercalated.
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Lv, Jing, Tianhua Zhou, Qiang Du, Kunlun Li und Liangwei Jin. „Research on the Bond Behavior of Preplaced Aggregate Concrete-Filled Steel Tube Columns“. Materials 13, Nr. 2 (09.01.2020): 300. http://dx.doi.org/10.3390/ma13020300.
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In order to investigate the bond behavior of preplaced aggregate concrete-filled steel tube (CFT-PAC) columns and the difference of bond behavior between CFT-PAC columns and normal concrete-filled steel tube (CFT-NC) columns, a total of 11 columns were prepared and the push-out tests were conducted. The experimental parameters included the type of concrete (preplaced aggregate concrete and normal concrete), concrete strength (C40, C50 and C60), cross-section dimension (D = 219 mm, 299 mm and 351 mm) and the thickness of steel tube (t = 6 mm and 8 mm). The results indicated that the CTF-PAC columns had a similar load-slip curves with CFT-NC columns. The bond stresses of the CFT-PAC columns were higher than that of the PAC-NC columns at the same concrete strength. Increasing compressive strength of PAC increased the critical bond strength and bond strength of CFT-PAC columns. With an increase of the L/D ratio, both of the slip corresponding to peak load and bond strength of CFT-PAC columns exhibited an increasing trend. A rise in the D/t ratio led to a decrease in the bond stress of CFT-PAC columns and an increase in slip corresponding to the peak load of CFT-PAC columns. The proposed bond stress–slip relationship model considerably matched the bond stress–slip relationship of CFT-PAC columns.
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Uhlmann, E., S. Thom, L. Prasol, K. Haberbosch und S. Drieux. „Elektromechanisches Glattwalzen von Stahllegierungen*/Electromechanical burnishing of steel alloys. Principal investigation of electromechanical burnishing of steel alloys“. wt Werkstattstechnik online 109, Nr. 07-08 (2019): 598–604. http://dx.doi.org/10.37544/1436-4980-2019-07-08-88.
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Das elektromechanische Glattwalzen (EMG) beschreibt ein Umformverfahren, welches aufgrund des zusätzlich durch das Werkstück fließenden Stroms ein kombiniertes Fertigungsverfahren darstellt. Der Stromfluss induziert, bedingt durch den Ohmschen Widerstand R, in der oberflächennahen Randschicht des Werkstücks einen Wärmeeintrag. Hieraus resultiert eine temperaturbedingte Abnahme der Dehngrenze beziehungsweise Streckgrenze sowie der Zugfestigkeit im Werkstück. Der nachgelagerte Umformprozess durch eine Glattwalzrolle erfolgt somit bei einem lokal erhöhten Formänderungsvermögen. Im Beitrag wird das Potenzial des EMG für die Bearbeitung der Stahllegierungen C60 und 41Cr4 aufgezeigt. Electromechanical burnishing (EMG) is a further development of burnishing (MG). By joining a forming process (MG) with an electrical current, EMG results in a combined manufacturing process. Due to the heating process – induced by current flow – an increased material formability occurs in the forming zone. In this paper, the influence of EMG on the surface and metallographic properties of the steel alloys C60 and 41Cr4 is analyzed.
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Wang, Yu Dong, und Xiao Chun Fan. „Experimental Research on Physical and Mechanical Properties of Steel Fiber High-Strength Concrete“. Advanced Materials Research 168-170 (Dezember 2010): 1061–64. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1061.
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Based on experiment, the mix proportion matching with the design and construction requirements is obtained. It meets with the requirement of pump structure on the basis of meeting the strength requirement. On this basis, the basic physical and mechanical performance is studied and the conclusion is that steel fiber high-strength concrete has excellent resistance to splitting, bending and drying shrinkage. The splitting strength and bending strength of steel fiber high-strength concrete named CF60-2 is respectively 38.7% and 56.8% higher than that of plane concrete named C60. The drying shrinkage rate of CF60-2 is 45.5% lower than that of C60 in three days. The results have an important guiding significance to steel fiber high-strength concrete in theoretical and engineering practice.
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Wang, Hai Yang, Pei Yan Huang, Xiao Hong Zheng und Xin Yan Guo. „Thermal Fatigue Performance of Steel Fiber Reinforced Polymer High Strength Concrete“. Applied Mechanics and Materials 174-177 (Mai 2012): 1060–66. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.1060.
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To discover the fatigue behavior and durability of the new type fiber concrete named “steel fiber reinforced polymer high strength concrete (SFPHC)”, considering climatic conditions in Guangdong Province, using research method of theoretical analysis combined with experimental study, thermal fatigue behavior of SFPHC used in bridge superstructure in three different temperatures (20°C，50°C，80°C) is discussed and compared with concrete C60 which has similar static mechanical properties at room temperature. The results show that the thermal fatigue performance of SFPHC can be described effectively with the proposed computing formula, and the fatigue performance has been greatly enhanced compared with the C60 concrete.
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Gupta, B. K., Bharat Bhushan, C. Capp und J. V. Coe. „Materials characterization and effect of purity and ion implantation on the friction and wear of sublimed fullerene films“. Journal of Materials Research 9, Nr. 11 (November 1994): 2823–38. http://dx.doi.org/10.1557/jmr.1994.2823.
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In previous studies, sublimed C60-rich fullerene films on silicon, when slid against a 52100 steel ball under dry conditions, have exhibited low coefficient of friction (∼0.12). Films with different purities can be produced by sublimation at different substrate temperatures. In this paper, effects of purity of fullerene films and ion implantation of the films with Ar ions on the friction and wear properties of sublimed fullerene films are reported. C60-rich films (called here films with high purity) exhibit low macroscale friction. An increased amount of C70 and impurities in the fullerene film determined using Raman and Fourier transform infrared (FTIR), increases its coefficient of friction. Microscale friction measurements using friction force microscopy also exhibited similar trends. Low coefficient of friction of sublimed C60-rich films on silicon is probably due to the formation of a tenacious transfer film of C60 molecules on the mating 52100 steel ball surface. Based on scanning tunneling microscopy (STM), transmission electron microscopy (TEM), and high resolution TEM (HRTEM), we found that fullerene films primarily consisted of C60 molecules in a fcc lattice structure. Nanoindenter was used to measure hardness and elastic modulus of the as-deposited films. Ion-implantation with 1 × 1016 Ar+ cm−2 reduced macroscale friction down to about 0.10 from 0.12 with an increase in wear life by a factor of 4; however, doses of 5 × 1016 ions cm−2 gave three times higher friction and poorer wear life; higher doses disintegrated the C60 molecules. Based on STM, TEM, Raman, FTIR, and laser desorption Fourier-transform ion cyclotron resonance mass spectrometer (LD/FT/ICR) studies, we found that the ion implantation with a dose of 1 × 1016 Ar+ cm−2 resulted in smoothening of the fullerene film surface probably by compacting clusters, but without disintegrating the C60 molecules. However, a high dose of 5 × 1016 Ar+ cm−2 damaged the C60 molecules, converting it to an amorphous carbon. Nanoindentation studies show that ion implantation with a dose of 1 × 1016 Ar+ cm−2 resulted in an increase in the hardness from about 1.2 to 4.0 GPa and in elastic modulus from about 70 to 75 GPa and modified the elastic-plastic deformation behavior.
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Yu, Xin Wen, Yu Hai Gao, Dong Hao, Shu Zhi Li und Lan Ying Wang. „The Research and Application of Self-Compacting Concrete“. Key Engineering Materials 302-303 (Januar 2006): 384–90. http://dx.doi.org/10.4028/www.scientific.net/kem.302-303.384.
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Self-compacting concrete (SCC) has the environmentally friendly effect. The SCC can be prepared by using the technical approaches of “Double adding” (adding mineral admixtures and chemical admixtures and) low W/B (the ratio of water to composite binder). According to the requirements of design and construction, SCC of C30～C60 can be produced by selecting materials used and adjusting the amount and composition of composite binder, the dosage and composition of high performance chemical admixture as well as W/B, based on the reasonable component of SCC with volume. It had been applied successfully in some construction works in several, such as concrete filled steel pipe column and strengthening of concrete structure.
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Zhu, Tao, Hongjun Liang, Yiyan Lu, Weijie Li und Hong Zhang. „Axial behaviour of slender concrete-filled steel tube square columns strengthened with square concrete-filled steel tube jackets“. Advances in Structural Engineering 23, Nr. 6 (16.11.2019): 1074–86. http://dx.doi.org/10.1177/1369433219888726.
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This article investigates the behaviour of slender concrete-filled steel tube square columns strengthened by concrete-filled steel tube jacketing. The columns were realised by placing a square outer steel tube around the original slender concrete-filled steel tube column and pouring strengthening concrete into the gap between the inner and outer steel tubes. Three concrete-filled steel tube square columns and seven retrofitted columns ranging from 1200 to 2000 mm were tested to failure under axial compression. The experimental parameters included three length-to-width ( L/ B1) ratios, three width-to-thickness ( B1/ t1) ratios and three strengths of concrete jacket (C50-grade, C60-grade and C70-grade). Experimentally, the retrofitted columns failed in a similar manner to traditional slender concrete-filled steel tube columns. After strengthening, the retrofitted columns benefitted greatly from the component materials, with their load-bearing capacity and ductility notably enhanced. These enhancements were mainly brought about by sectional enlargement and good confinement of concrete. A finite element model was developed using ABAQUS to better understand the axial behaviour of the retrofitted specimens. A parametric study was conducted, with parameters including the length of the column, thickness of the outer steel tube, strength of the concrete jacket, yield strength of the outer steel tube, thickness of the inner steel tube and strength of the inner concrete. Furthermore, the finite element model was adopted to study the behaviour of rust-damaged and post-fire slender concrete-filled steel tube square columns strengthened by square concrete-filled steel tube jacketing. A modified formula was proposed to predict the load-bearing capacity of retrofitted specimens, and the numerical results agreed well with the experiments and the finite element results of undamaged, rust-damaged and post-fire specimens. It could be used as a reference for practical application.
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Sahil, Thakur, Singh Supreet und Kumar Manoj. „Hot Corrosion Behavior and study of Friction Stir Processed C60 Steel“. Indian Journal of Science and Technology 11, Nr. 28 (01.07.2018): 1–6. http://dx.doi.org/10.17485/ijst/2018/v11i28/130796.
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14
Shi, Qi Yin, Chao Liu, Li Lin Cao und Zhen Wang. „Study on the Performance of the New High-Strength Steel-Encased Concrete Composite Beam (SCCB)“. Advanced Materials Research 756-759 (September 2013): 161–65. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.161.
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On the basis of the theoretical study and application of ordinary steel-encased concrete composite beam, this paper will focus on a new high-strength steel-encased concrete composite beam, and mainly studies high-performance steel Q420 and Q460, as well as high-strength concrete C60 and C80. Besides, an experimental study of 5 simply-supported beams is made, and the load-deflection curves of new SCCB are analyzed. The calculation formula of load which changes with depth of section and bending strength of the cross section is also analyzed. It is suggested that the calculated results announced should be identical with the experimental results.
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Abbood et al., Amal. „Synthesis of C60 Nanotube from Pyrolysis of Plastic Waste (Polypropylene) with Catalyst“. Baghdad Science Journal 17, Nr. 2(SI) (21.06.2020): 0624. http://dx.doi.org/10.21123/bsj.2020.17.2(si).0624.
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Fullerene nanotube was synthesized in this research by pyrolysis of plastic waste Polypropylene (PP) at 1000 ° C for two hours in a closed reactor made from stainless steel using molybdenum oxide (MoO3) as a catalyst and nitrogen gas. The resultant carbon was purified and characterized by energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD). The surface characteristics of C60 nanotubes were observed with the Field emission scanning electron microscopy (FESEM). The carbon is evenly spread and has the highest concentration from SEM-EDX characterization. The result of XRD and FESEM shows that C60 nanotubes are present in Nano figures, synthesized at 1000 ° C and with pyrolysis temperature 400° C. The synthesis operation doing in one reactor and limited time.
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Chen, Shang Jiang, und Xiao Ning Zhang. „Preparation and Application of Self-Compacting Concrete-Filled Steel Tube Using Polymer Admixtures“. Advanced Materials Research 415-417 (Dezember 2011): 265–71. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.265.
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Self-compacting concrete-filled steel tube is different from ordinary self-compacting concrete in many aspects. According to the demands of on-site construction conditions and construction technology of continuous pumping lift-up method for the project of Huaxi No.1 steel tube arch bridge, property requirements of self-compacting concrete filled steel tube were proposed in this paper. By using the preparation techniques such as optimization of basic parameters of concrete mix proportion, admixture composition and mineral admixture addition, self-compacting concrete filled steel tube was prepared with the properties such as initial slump more than 24cm, initial slump flow above 650mm, T50 between 5s and 15s, no slump loss for 4h, no bleeding, strength grade above C60 and shrinkage-compensation etc. It was applied in the steel tube arch bridge project successfully using the construction technology of pumping lift-up method.
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Duplák, Ján, Michal Hatala, František Botko und Miroslav Kormoš. „Analysis of Cutting Tools Durability Importance in Turning Process of Steel C60“. Key Engineering Materials 669 (Oktober 2015): 319–26. http://dx.doi.org/10.4028/www.scientific.net/kem.669.319.
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Durability of cutting tools consists form several partial sections. Determination of durability for each specific turning knife, milling head or cutting insert is very complicated. Wide spectrum of factors affects durability of cutting tools, which is important to study and analyze to point out the differences in this process. Major factor influencing cutting process is technological system, which consists of machine, toll, work piece and cutting conditions. In addition to used cutting material there are more parameters affecting cutting process. Properly selected cutting conditions and coating of cutting tool can accelerate production process, improve quality of products or vice versa economically disadvantages. Article deal with analyze of durability of selected cutting materials and compares results of experiment with F.W. Taylor rules and standard ISO 3685. Article highlights on differences developed due to different technological systems in turning process of steel C60. The article also describes process how to define and analytically expressT-vcdependence.
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Xiao, Jian Zhuang, Chuan Zeng Zhang und Horst Falkner. „Bond Strength and Damage of Long Rebar Anchored in HPC under Static and Fatigue Loading“. Key Engineering Materials 324-325 (November 2006): 867–70. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.867.
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This paper presents an experimental study on the anchorage behaviour of long high-strength steel rebars embedded in high-performance concrete (HPC) under both static loading and fatigue loading. The HPC was designed as C60 with its cube compressive strength larger than 60 MPa, and the high-strength steel bar was adopted as HRB500 with its characteristic yield strength equals 500 MPa. Under 3×106 fatigue loading cycles and then followed by a monotonous static loading, the strain and the stress state of the reinforcement bar, and the bond stress between the concrete and the 700 mm-long bar were investigated. Based on the test results and the ANSYS finite element analysis, the bond behaviour between HPC and long high-strength steel bars is discussed.
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Liu, Xiaohu, Zhishu Yao, Weipei Xue, Xuesong Wang und Xianwen Huang. „Experimental Study of the Failure Mechanism of the Anchorage Interface under Different Surrounding Rock Strengths and Ambient Temperatures“. Advances in Civil Engineering 2021 (30.04.2021): 1–17. http://dx.doi.org/10.1155/2021/6622418.
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In order to study the anchoring instability mechanism of surrounding rock in deep roadway, the failure mechanism of the bolt-anchoring agent interface was studied by simulating different strength rock mass and ground temperature environment, using C20, C40, and C60 strength concrete and steel pipe to simulate different surrounding rock strength environments. Indoor pull-out tests were carried out to study the pull-out load displacement relationship, ultimate pull-out force, residual anchoring force, the distribution law of axial stress and tangential stress along the bar, and the energy consumption value of drawing failure at 20, 50, and 70°C. The test results show that, with the decrease of surrounding rock strength or the increase of ambient temperature, the pull-out force, residual anchoring force, and energy consumption value of anchorage interface gradually decrease; under different axial forces, the axial force distribution of the rod body decreases exponentially from the anchoring end to the opposite end; and the shear stress transfers to the deep part of the anchor body with the increase of the load. According to the failure phenomenon of the specimen, the failure modes of the bolt bolt-anchorage agent interface can be divided into shear slip mode and shear expansion slip mode. The shear expansion slip formula of anchorage interface is derived. Using high-strength and temperature-resistant resin anchoring agent for comparative test, the rationality of the mechanism analysis is proved, which provides more clear guidance for the construction of anchor support.
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Miyazaki, Yuya, Shimpei Miyamato, Kyosuke Yoshimi und Kouichi Maruyama. „Novel Low-temperature Solid-carburizing Using C60 Fullerene for Austenitic Stainless Steel SUS316L“. ISIJ International 52, Nr. 11 (2012): 2076–82. http://dx.doi.org/10.2355/isijinternational.52.2076.
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Kawulok, Rostislav, Ivo Schindler, Petr Kawulok, Janusz Dänemark, Petr Opěla und Stanislav Rusz. „Study of Phase Transformation of Medium Carbon Steel after Hot Plastic Deformation“. Solid State Phenomena 258 (Dezember 2016): 599–602. http://dx.doi.org/10.4028/www.scientific.net/ssp.258.599.
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The CCT and DCCT diagrams of steel C60 (with approx. 0.6 % C) were constructed on the basis of dilatation tests with and/or without an influence of the previous deformation and they were then compared, order to make an evaluation of the influence of the previous deformation on the phase transformation kinetics. For the execution of the experiment, the dilatation module of the plastometer Gleeble 3800 was used. The accuracy of the diagrams was faced with metallographic analyses and measurements. The previous deformation expressly retarded a bainite transformation and slightly accelerated ferrite and pearlite transformations. The martensite start temperature was practically not influenced by the previous deformation; however, the applied deformation caused the creation of the martensite at lower cooling rates.
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Morse, K., T. P. Weihs, A. V. Hamza, M. Balooch, Z. Jiang und D. B. Bogy. „Nanomechanical Properties of SiC Films Grown From C60 Precursors Using Atomic Force Microscopy“. Journal of Tribology 119, Nr. 1 (01.01.1997): 26–30. http://dx.doi.org/10.1115/1.2832475.
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The mechanical properties of SiC films grown via C60 precursors were determined using atomic force microscopy (AFM). Conventional silicon nitride and diamond-tipped steel AFM cantilevers were employed to determine the film hardness, friction coefficient, and elastic modulus. The hardness is found to be 26 GPa by nanoindentation of the film with a Berkovich diamond tip. The friction coefficient for the silicon nitride tip on the SiC film is about one half to one third that for silicon nitride sliding on a silicon substrate. By combining nanoindentation and AFM measurements an elastic modulus of ~300 GPa is estimated for these SiC films.
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Mulewicz, Bartłomiej, Grzegorz Korpala, Jan Kusiak und Ulrich Prahl. „Autonomous Interpretation of the Microstructure of Steels and Special Alloys“. Materials Science Forum 949 (März 2019): 24–31. http://dx.doi.org/10.4028/www.scientific.net/msf.949.24.
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The main objective of presented research is an attempt of application of techniques taken from a dynamically developing field of image analysis based on Artificial Intelligence, particularly on Deep Learning, in classification of steel microstructures. Our research focused on developing and implementation of Deep Convolutional Neural Networks (DCNN) for classification of different types of steel microstructure photographs received from the light microscopy at the TU Bergakademie, Freiberg. First, brief presentation of the idea of the system based on DCNN is given. Next, the results of tests of developed classification system on 8 different types (classes) of microstructure of the following different steel grades: C15, C45, C60, C80, V33, X70 and carbide free steel. The DCNN based classification systems require numerous training data and the system accuracy strongly depend on the size of these data. Therefore, created data set of numerous micrograph images of different types of microstructure (33283 photographs) gave the opportunity to develop high precision classification systems and segmentation routines, reaching the accuracy of 99.8%. Presented results confirm, that DCNN can be a useful tool in microstructure classification.
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Szweda, Zofia, und Zbigniew Buliński. „Application of inverse methodology to estimation of chloride diffusion coefficient in concrete of prestressed precast slab“. MATEC Web of Conferences 174 (2018): 01008. http://dx.doi.org/10.1051/matecconf/201817401008.
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Work presents an investigation of chloride penetration of HC-500 prestressed concrete slabs made of precast concrete. This type of concrete slabs is widely used to construct floors in steel or reinforced concrete framing buildings. In such solutions ceiling can be considered as a simple-supported beam. Considered precast concrete was made of C50/C60 concrete with use of Portland cement CEM II 52.5 R. Investigated specimens were sampled directly from the upper part of prestressed concrete slabs. The process of chloride penetration in concrete can be described by the non-linear diffusion equation. In the paper Bayesian inverse technique was applied to estimate diffusion coefficient of chloride in concrete treated as a saturated porous material. Unknown distribution of estimated parameters was sampled with use of Metropolis-Hastings algorithm which allowed us to obtain unknown values and their error bounds. Obtained values of diffusion coefficient were confronted against values obtained with use of norms: NT BUILD 443 and ASTM C 1556 - 03 and against previously developed methodology based on the analytical solution of the diffusion equation.
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Lan, Wen Jian, Baohong Wu und Zhi Yong Liu. „Effect of Surface Applied Inhibitor on Corrosion Rate of Steel Bar in High Strength Concrete with Various Admixed Chlorides“. Applied Mechanics and Materials 174-177 (Mai 2012): 1184–87. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.1184.
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Effect of surface applied inhibitor on the durability of high strength reinforced concrete with various chloride content has been investigated in this paper. The C60 concrete specimens contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials were prepared and experienced in months exposure tests after painting with 400 g/m2 inhibitor. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) of the steel rebar in specimens was tested. The results indicate that after surface painting the inhibitor for 28d the bars in concrete specimens with 0.5% NaCl and bar with 25mm cover in specimen with 1% NaCl show the average corrosion rate lower than that of control one (No.0, no painted inhibitor). While the corrosion current of rebar (38mm cover) for No.2 specimen with 1% NaCl and bars for No.3 specimen with 1.5% NaCl are still higher than that of the control one (No.0). The results indicate that the surface painted inhibitor on C60 concrete are effective to inhibit the corrosion of bar concrete at low or middle chloride conditions and not enough to repair the bars in high chloride contaminated concrete. The lower organic nitrogen content in 40-50mm depth also indicates that the inhibitor is harder to penetrate into deeper parts of high strength concrete compared with low or middle grade concrete.
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Ye, Taoping, Wanlin Cao, Yixuan Zhang und Zhengwen Yang. „Flexural Behavior of Corroded Reinforced Recycled Aggregate Concrete Beams“. Advances in Materials Science and Engineering 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/2957036.
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Recycling concrete not only reduces the use of virgin aggregate but also decreases the pressure on landfills. As a result, recycled coarse aggregate (RCA) is extensively recommended for new construction projects. However, the flexural behavior of corroded reinforced recycled aggregate concrete (RAC) beams is uncertain. The experimental research presented in this paper was performed to investigate the flexural behavior of corroded reinforced RAC beams compared to that of corroded reinforced natural aggregate concrete (NAC) beams and consequently explore the possibility of using RAC beams in corrosive environments. Four different percentages of RCA in total mass of coarse aggregate in concrete mixtures (0%, 33%, 66%, and 100%) and two different concrete strengths (C30, C60) were the governing parameters. The electrochemical method was adopted to accelerate steel corrosion. Full-scale tests were performed on eight simply supported beams until the failure load was reached. Comparison of load-deflection behavior, crack patterns, failure modes, ductility, and ultimate flexural capacity of corroded reinforced NAC and RAC beams was made based on the experimental results obtained. The comparison results show that the flexural behavior of corroded reinforced RAC beams with an appropriate percentage of RCA is satisfactory compared to the behavior of NAC beams.
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Abouridouane, Mustapha, Gottfried Laschet, Viktor Kripak, Jens Dierdorf, Ulrich Prahl, Guido Wirtz und Thomas Bergs. „Microstructure-based approach to predict the machinability of the ferritic-pearlitic steel C60 by cutting operations“. Procedia CIRP 82 (2019): 107–12. http://dx.doi.org/10.1016/j.procir.2019.04.013.
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Duplák, Ján, Michal Hatala, Jozef Zajac, Karol Vasilko, Miroslav Kormoš und Slavko Jurko. „The Comprehensive Comparison of the Selected Cutting Materials with Standard ISO 3685 in Machining Process of Steel C60“. Applied Mechanics and Materials 718 (Dezember 2014): 93–98. http://dx.doi.org/10.4028/www.scientific.net/amm.718.93.
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The main part of Standard ISO 3685 is T-vc dependence for various cutting materials. The Standard ISO 3685 contains main properties and characteristics for three most important cutting materials those are used in engineering practice. These cutting materials are used for cutting tools made of high speed steel, cutting ceramic and sintered carbide. Some types of cutting materials are defined by means of descriptions in standards ISO, some types by means of catalogues from the manufacturer. There are a lot of types of cutting materials they have not been defined theirs properties exactly yet and theirs properties have to be defined on experiments. There is a presumption that descriptions in standards ISO are not correct and these standards have to be examined and verified, because that this fact have to be confirmed or disproved. Accuracy and completeness technical standards ISO are very important part quality of manufacturing. Article describes process how to define T-vc dependence for cutting tools made of high speed steel, cutting ceramic and sintered carbide, because were found deficiencies in valid standard ISO 3685.
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Wu, Jing, Fa Zhou Wang, Yue Li, Wen Yang und Shu Guang Hu. „Experimental Research on Seismic Behavior of RC Column with Different Concrete under Horizontal Low Cyclic Loading“. Advanced Materials Research 374-377 (Oktober 2011): 2041–45. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.2041.
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On the premise of maintaining certain vertical bearing capacity, the frame structure dissipates seismic energy by elastic-plastic deformation in elastic-plastic stage of earthquake action. Using lightweight concrete in structure not only can reduce the its dead weight, decrease the earthquake power; also meet the concrete strength, stiffness and elastic modulus requirements of important structure, so as to improve its energy dissipation capacity. This paper researched the effect of concrete materials, including or such as C60 high strength Lightweight concrete (HSLC), high strength concrete (HSC) and high strength Light weight aggregate concrete (HSLAC), on the seismic behavior of RC column under horizontal low cyclic loading, respectively and the match relationship between concrete and steel reinforcement cage was analyzed.
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Liu, Yuan, Wei Wang, Changqing Wang, Shuosong Bi und Jianming Zhu. „D-Shaped Concrete-Filled Steel Tube Structure in Bridge Engineering“. Advances in Civil Engineering 2021 (08.03.2021): 1–12. http://dx.doi.org/10.1155/2021/6611003.
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With the continuous progress of the construction industry, the requirements for concrete in the bridge engineering are getting higher and higher. This research mainly discusses the detection of D-shaped concrete-filled steel tube structure in bridge engineering. In this study, the D-shaped concrete-filled steel tube member was used as the research object, and the load-displacement curve of the D-shaped concrete-filled steel tube compression-bending member was analyzed by the fiber model program. In the determination of the bonding state of the concrete-filled steel tube interface, in order to avoid the impact of mechanical and manual vibrating and the difference in concrete pouring methods on the test, the study uses C60 self-compacting microexpansion concrete. While pouring the specimens, three sets of cube specimens with a side length of 100 mm are reserved to determine the mechanical properties of the concrete simultaneously. In the temperature shock measurement of the concrete-filled steel tube specimen, the concrete-filled steel tube specimen was placed in a resistance heater during the simulated heating stage and heated to 20°C, 40°C, 60°C, and 80°C at room temperature. When measuring the mechanical properties of the specimen under the axial load, the specimen is heated from room temperature to the temperature of the entire section to reach 20°C, 40°C, 60°C, and 80°C. After preloading, the load of each level is 10t for continuous operation. Load and record the strain of the steel pipe and concrete under each load. If only the radial effect of the steel tube on concrete is considered, the temperature of 11°C, 20°C, and 80°C is the best ambient temperature. The results show that the D-shaped steel tube concrete interface state can provide a certain theoretical and experimental reference for the optimization of the steel tube concrete interface, ensuring the long-term working performance of the steel tube concrete under the harsh environment.
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Panda, Anton, Ján Duplák, Jozef Jurko, Marcel Behún und Marek Jančík. „The Analysis of Ceramic Cutting Tools Durability in Machining Process of Steel C60 Applied According to Standard ISO 3685“. Applied Mechanics and Materials 275-277 (Januar 2013): 2190–94. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.2190.
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Very important cutting tool property is its durability. Durability of cutting tool defines lifetime of this cutting tool and it determines its suitability for select technological operation. Technical science defines a lot of different factors, that they may be cause of shorter cutting tool lifetime. For increase cutting tool durability is necessary maximally possible elimination of these factors. Determination of cutting tool durability is very important, because provides comprehensive information how to determine appropriate technological conditions for selected cutting tool. In engineering is for determination of cutting tools durability used T-vc dependence. The article describes process how to create durability dependence for cutting tools made of cutting ceramic by means of T-vc dependence in machining process of C60.
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Wawrzeńczyk, Jerzy, Agnieszka Molendowska und Adam Kłak. „Frost durability of steel fiber self-compacting concrete for pavements“. Baltic Journal of Road and Bridge Engineering 11, Nr. 1 (25.03.2016): 35–42. http://dx.doi.org/10.3846/bjrbe.2016.04.
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The paper presents the results from the research on self-compacting concrete with different steel fibre type addition. The reference self-compacting concrete mix with water/binder = 0.33 was prepared, then modified with steel fibres in the amounts of 0–60 kg/m3 and air entrained with polymer microspheres (40 μm diameter). The major objective of the research was to determine the effect of steel fibre and air content on the self-compacting concrete mix properties and hardened concrete frost durability. The tests also included internal cracking and scaling resistance evaluation for concrete specimens subjected to cyclic freeze-thaw process − two beams were frozen in air and two beams were partially submerged in water and then frozen. The scaling resistance was tested using the slab method on the specimens with sawn surface and on the specimens with natural finished surface. Non-air entrained steel fibrereinforced concretes, despite their high strength class (C55/67–C60/75) and medium absorption (4.34–5.11%), showed unsatisfactory resistance to internal cracking and scaling tests. The beams partially submerged in water failed after 100 freeze-thaw cycles, which confirms a significant influence of water uptake from moist environment during freeze-thaw cycles and the acceleration of the damage process. Test results indicate that air entrainment with polymer microspheres is a very effective method and allows obtaining very good air pore structure parameters and frost resistance results. The specimens with top − finished surface exhibited less damage in the scaling resistance tests in relation to the specimens with sawn surface.
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Graf, Marcel, Madlen Ullmann, Grzegorz Korpala, Hendrik Wester, Birgit Awiszus, Rudolf Kawalla und Bernd-Arno Behrens. „Forming and Oxidation Behavior During Forging with Consideration of Carbon Content of Steel“. Metals 8, Nr. 12 (27.11.2018): 996. http://dx.doi.org/10.3390/met8120996.
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Developments in technology rely increasingly on the numerical simulation of single process steps up to whole process chains using commercially available or user-written software systems, mostly based on the finite element method (FEM). However, detailed simulations require realistic models. These models consider the relevant material-specific parameters and coefficients for the basic material, surface phenomena, and dies, as well as machine kinematics. This knowledge exists to some extent for certain materials, but not in general for groups of steel that depend on alloying elements. Nevertheless, the basic material and its behavior before, during, and after hot deformation must be understood when designing and describing die-forging processes by experimental and numerical simulations. This is why a new mathematical approach has been formulated for forming behavior and recrystallization kinetics, taking into account the carbon content of the base material, the initial microstructure, and the reheating mode. Furthermore, there have been no studies investigating the influence of varying a single chemical element, such as the carbon content, with regard to the oxidation behavior, including the internal structure (e.g., pores) at high temperatures. In this context the majority of studies were performed with steel grade C45 (material no. 1.0503), which was chosen as base material for the experiments conducted. To identify the effects of the alloying element carbon on the material and oxidation behavior, steel grades C15 (material no. 1.0401) and C60 (material no. 1.0601) were also investigated. The investigations revealed a dependence of the material behavior (microstructure and surface) on the alloying system. Based on the experimental results, the mathematical models formulated were parameterized and implemented in the FE-software Simufact Forming (Simufact Engineering GmbH, Hamburg, Germany) by means of user subroutines. Furthermore, a correlation between the thickness of the oxide scale layer and friction was determined in ring compression tests and accounted for in the software code. Finally, real forging tests were carried out under laboratory conditions, with all three investigated steels for calibration of the materials as well as the FE models.
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Ma, Qian, Dan Wu, Xu Dong Shi und Xiu Gen Jiang. „Numerical Analysis of Anti-Impact Performances of the Reinforced Concrete Slab“. Applied Mechanics and Materials 249-250 (Dezember 2012): 1063–68. http://dx.doi.org/10.4028/www.scientific.net/amm.249-250.1063.
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The influence of the structure parameters on the anti-impact performances of the reinforced concrete slab is studied in the article. The reinforced concrete model is established by using ANSYS 13.0/LS-DYNA and nonlinear finite element theory and the parameterized modeling is achieved. The results show that the increase of the thickness of the slab and the steel bar diameter result in the enhancement of impact resistant capability of the slab; a appropriate quantity of reinforcement is significant; Increasing the concrete strength has a distinct impact on the slab’s impact resistance when using relatively low strength concrete. However the influence becomes weak after the concrete strength comes to C60 and higher. The fruits are useful to the designing of reinforced concrete slabs.
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Vaitkus, Audrius, Judita Gražulytė, Ovidijus Šernas, Martynas Karbočius und Rafal Mickevič. „Concrete Modular Pavement Structures with Optimized Thickness Based on Characteristics of High Performance Concrete Mixtures with Fibers and Silica Fume“. Materials 14, Nr. 12 (21.06.2021): 3423. http://dx.doi.org/10.3390/ma14123423.
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Usually, C30/37 strength class concrete is used to construct concrete pavements on a rigid, semi-rigid or flexible base. Concrete with such a strength delivers essential design characteristics: flexural strength and tensile splitting strength are between 4.5–5.4 MPa and 2.8–3.7 MPa, respectively. Design characteristics can be significantly increased by densifying the concrete mixture, i.e., adding silica fume, steel or polypropylene macro fibers. As high-performance concrete characteristics are 20–60% higher than those for standard concrete (C30/37), new possibilities to reduce the thickness of concrete pavement slabs appear. The theoretical analysis of concrete pavement structures with high-performance concrete mixtures (C40/50, C45/55 and C50/60) showed that slab thickness could be reduced by 6–39% compared to a standard concrete pavement structure depending on the concrete properties and design method. From all those pavement structures, three concrete mixtures were determined as the most rational ones in terms of PCP thickness reduction and total pavement cost: (i) with 49.5 kg/m3 of steel fibers and 25.2 kg/m3 of silica fume; (ii) with 10.0 kg/m3 of polypropylene fibers (type A); (iii) with 49.5 kg/m3 of steel fibers.
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Hassan, Nazly, und Rudolf Holze. „A comparative electrochemical study of electrosorbed 2- and 4-mercaptopyridines and their application as corrosion inhibitors at C60 steel“. Journal of Chemical Sciences 121, Nr. 5 (September 2009): 693–701. http://dx.doi.org/10.1007/s12039-009-0083-y.
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Yuan, Jian Song, Dan Ying Gao und Lin Yang. „Research on Strength of Steel Fiber Reinforced Concrete at Low Fiber Volume Fraction Based on Binary Variance Analysis“. Advanced Materials Research 742 (August 2013): 243–48. http://dx.doi.org/10.4028/www.scientific.net/amr.742.243.
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Based on the strength tests, including compressive strength, split tensile strength, shear strength , of steel fiber reinforced concrete (SFRC) with different concrete strength grades (C20~C50) at low fiber volume fraction (0~0.7%), the influences of concrete strength grades and steel fiber volume on concrete strengths were studied, and the effect significance levels of the two factors was analyzed through the binary variance analysis. The results show that when the concrete strength grades are amongst C20 ~ C50 and steel fiber volume rates lie in the range 0~0.7%,the strengths of SFRC rises as concrete strength grade and steel fiber volume ratio increase ; the influence of concrete grade is more significant than that of steel fiber volume ratio on compressive strength and split tensile strength of SFRC; the influence of steel fiber volume fraction is less significant than that of concrete strength grades on shear strength of SFRC.
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Wang, Yan Ming, Ke Liu, Wen Wen Yang und Ji Zheng Sun. „Properties of Flexible Fiber and Rigid Fiber Reinforced Cement Concrete Used on Surface Layer of Wharf Pavement“. Advanced Materials Research 224 (April 2011): 70–78. http://dx.doi.org/10.4028/www.scientific.net/amr.224.70.
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Different fiber reinforced concrete was experimentally investigated by adding flexible fiber and rigid fiber respectively into C20, C30 and C40 plain concrete. First the workability of fiber reinforced concrete was tested. Then the mechanical property and frost resistance property was tested after curing on standard condition for 28 days. The flexible fiber is American Durafiber and domestic nylon fiber. The rigid fiber is domestic steel fiber. The result shows that fiber concrete can improve cohesiveness and water retention, the flexible fiber reinforced concrete presents more apparent. Compared with plain concrete, the slump and setting time decreases a little for flexible fiber reinforced concrete and increases a little for rigid fiber reinforced concrete. The compressive strength and flexural strength of fiber reinforced concrete can be increased compared with plain concrete. The rigid fiber reinforced concrete presents more obviously. For example, the compressive strength and the flexural strength of C30 concrete with the addition of steel fiber were increased by 24% and 34% respectively. The frost resistance of fiber reinforced concrete improves compared with plain concrete. The flexible fiber reinforced concrete presents more noticeably. For example, after 250 freezing-thawing cycles, the mass loss of C30 concrete with the addition of Durafiber is decreased by 15% and the relative dynamic elastic modulus is increased by 6% compared with plain concrete.
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Kim, Jaesung, Hongshin Lee, Ju-Yeon Lee, Kang-Hee Park, Woongseob Kim, Jeong Hoon Lee, Hyun-Jin Kang et al. „Photosensitized Production of Singlet Oxygen via C60 Fullerene Covalently Attached to Functionalized Silica-coated Stainless-Steel Mesh: Remote Bacterial and Viral Inactivation“. Applied Catalysis B: Environmental 270 (August 2020): 118862. http://dx.doi.org/10.1016/j.apcatb.2020.118862.
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Yao, Zhishu, Yu Fang, Ping Zhang und Xianwen Huang. „Experimental Study on Durability of Hybrid Fiber-Reinforced Concrete in Deep Alluvium Frozen Shaft Lining“. Crystals 11, Nr. 7 (23.06.2021): 725. http://dx.doi.org/10.3390/cryst11070725.
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This article proposes hybrid fiber-reinforced concrete (HFRC) mixed with polyvinyl alcohol fiber (PVA) and polypropylene steel fiber (FST) as a wall construction material to improve the bearing capacity and durability of frozen shaft lining structures in deep alluvium. According to the stress characteristics and engineering environment of the frozen shaft lining, the strength, impermeability, freeze–thaw damage, and corrosion resistance are taken as the evaluation and control indexes. The C60 concrete commonly used in freezing shaft lining is selected as the reference group. Compared to the reference group, the test results show that the compressive strength of HFRC is similar to that of the reference concrete, but its splitting tensile strength and flexural strength are higher; according to the strength test, the optimum mixed content of 1.092 kg/m3 PVA and 5 kg/m3 FST are obtained. According to the impermeability test results, the mixing of PVA and FST can improve the impermeability resistance of concrete. For the freeze–thaw cycle test results, the mixing of PVA and FST can improve the frost resistance of concrete; based on the 120 days sulfate corrosion test, the mixing of PVA and FST will improve the corrosion resistance of concrete.
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Szmigiera, Elzbieta, Wojciech Zoltowski und Miroslaw Siennicki. „RESEARCH ON LOAD CAPACITY OF CONCRETE FILLED COLUMNS WITH BATTENED STEEL SECTIONS“. JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 16, Nr. 3 (30.09.2010): 313–19. http://dx.doi.org/10.3846/jcem.2010.36.
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The paper presents experimental and numerical results for selected built‐up steel columns filled with concrete. The laboratory tests were accompanied by numerical analysis carried out using general purpose, finite element program ABAQUS. Based on heretofore research presented in this paper, one may assumes that the application of concrete filled columns with battened steel sections is economically very profitable. For columns filled with concrete strength class C20/25 the increase of load bearing capacity was 42% and for elements filled with concrete strength class C50/60 ‐ above 100%. The application of the shorter distance between battens allowed to obtain additional increase of ultimate load (for concrete C20/25 ‐ about 8%). The numerical analysis also confirmed the increase of the load capacity for the columns. The best correlation between numerical and experimental results was obtained for the assumed eccentricity of 1 mm. Moreover the higher rigidity of those members in relation to steel columns is not connected with significant increase of the cost. The study was conducted as a part of the research project nr 4TO7E01528, founded by the Polish Ministry of Science and Higher Education. Santrauka Straipsnyje pristatomi plieniniu kolonu, užpildytu dvieju tipu betonu, eksperimentiniai ir skaitiniai tyrimu rezultatai. La‐boratoriniai bandymai ir skaitine analize buvo atliekami naudojant bendrosios paskirties baigtiniu elementu programa ABAQUS. Remiantis šiame straipsnyje pateiktais tyrimo rezultatais, galima daryti prielaida, kad kolonos iš standžiu plieniniu skerspjūviu, užpildytu betonu, yra labai ekonomiškos. Kolonos, užpildytos C20/25 betonu, laikomoji galia padidejo 42 %, o elemento, užpildyto C50/60, ‐ daugiau negu 100 %. Kai atstumas tarp sutvirtintu vietu trumpesnis, galima padidinti didžiausiaja apkrova (naudojant betono klase C20/25 ‐ apie 8 %). Skaitine analize patvirtino padidejusia kolonu laikomaja galia. Geriausia koreliacija tarp eksperimentiniu ir skaitiniu rezultatu buvo gauta esant tariamam 1 mm ekscentricitetui. Be to, didesnis šiu elementu standumas, palyginti su plieninemis kolonomis, nera susijes su išlaidu padidejimu. Šis mokslinis tyrimas buvo mokslinio projekto Nr. 4TO7E01528, kuri inicijavo Lenkijos studiju ir aukštojo mokslo ministerija, dalis.
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Zhang, Qian, Wenqing Zhang, Yu Fang, Yongjie Xu und Xianwen Huang. „Experimental Study on Mechanical Properties of High Performance Hybrid Fiber Concrete for Shaft Lining“. Applied Sciences 11, Nr. 17 (27.08.2021): 7926. http://dx.doi.org/10.3390/app11177926.
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In order to solve the problem of highly brittle shaft lining under dynamic loading, a combination of hybrid fiber concrete mixed with steel and polypropylene fiber is proposed to make shaft lining. C60, the concrete commonly used in shaft lining, was selected as the reference group. The static mechanical properties, dynamic mechanical properties, and crack failure characteristics of the hybrid fiber concrete were experimentally studied. The test results showed that compared to the reference group concrete, the compressive strength of the hybrid fiber-reinforced concrete did not significantly increase, but the splitting tensile strength increased by 60.4%. The split Hopkinson compression bar results showed that the optimal group peak stress and peak strain of the hybrid fiber concrete increased by 58.2% and 79.2%, respectively, and the dynamic toughness increased by 68.1%. The strain distribution before visible cracks was analyzed by the DIC technology. The results showed that the strain dispersion phenomenon of the fiber-reinforced concrete specimen was stronger than that of the reference group concrete. By comparing the crack failure forms of the specimens, it was found that compared to the reference group concrete, the fiber-reinforced concrete specimens showed the characteristics of continuous and slow ductile failure. The above results suggest that HFRC has significantly high dynamic splitting tensile strength and compressive deformation capacity, as well as a certain anti-disturbance effect. It is an excellent construction material for deep mines under complex working conditions.
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Yang, Hui, Shu Qiang Yuan, Feng Tao Liu, Jiong Chen, Chun Hua Zhou, Fang Wang und Zheng Xiang Shen. „Effect of Tempering Temperature on Mechanical Properties of 40CrMnSiB Steel“. Applied Mechanics and Materials 496-500 (Januar 2014): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.3.
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40CrMnSiB steel is a new type of B-containing structural steel. To research the effect of tempering temperature on mechanical properties of 40CrMnSiB steel, forging, normalizing and quenching are carried out on material firstly, then temper respectively at 350°C400°C450°C500°C550°C600°C650°C and 700°C. After tempering, mechanical properties are tested. Also the hardness, along a radius of section, of the material after tempering at 300°C is measured and the effect of tempering temperature on mechanical properties of 40CrMnSiB steel is analyzed. The results show that: the mechanical properties of 40CrMnSiB steel is sensitive to temper temperature, properties range a large scale with temper temperature; it has a strength of 1800MPa (or more) with good ductility, toughness and fine comprehensive mechanical properties; the hardness of the material after tempering at 300°C is over 50HRC, hardenability is fine, the main microstructure is martensite.
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Wang, Hai Chao, Xi Quan Xu und Li Jun Zhou. „The Experimental Study on Concrete-Filled Thin-Walled Square Steel Box Short Columns Fixed with Composite Steel Bar“. Applied Mechanics and Materials 94-96 (September 2011): 1590–95. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1590.
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The method of construction about the concrete-filled thin-walled square steel box short columns is studied in this paper. Composite steel is designed inside of the concrete-filled thin-walled square steel box short columns. The use of the transverse steel bars’ constraining effect on the concrete and bonding effect on the walls enhances the local stability and bearing capacity of the wall. According to the concrete strength C30/C35/C40 and the thickness of the steel 1.25mm/1.75mm/2.5mm,42 short column specimens are made and the size of all specimens is 200mm×200mm×690mm.The static bearing capacity test is done by the 500-ton electro-hydraulic serve testing machine. The whole curve is made .The composite steel and the thin-walled steel’s strain is tested. The results show that this method of construction has a certain effect on constrainting concrete and bonding effect on the walls, significantly improving their mechanical properties, increasing the carrying capacity and ductility, and it is easy to be accomplished.
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Valcuende, Manuel, Josep R. Lliso-Ferrando, Marta Roig-Flores und José M. Gandía-Romero. „Porous Structure of Ultra-High-Performance Fibre-Reinforced Concretes“. Materials 14, Nr. 7 (26.03.2021): 1637. http://dx.doi.org/10.3390/ma14071637.
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The aim of this experimental work was to study the porous structure of Ultra-High-Performance Fibre-Reinforced Concretes (UH) made with different fibre volume contents (0%, 1%, 2%) under several curing conditions (laboratory environment, 20 °C, 60 °C, 90 °C), comparing the results with those recorded for ordinary, high strength and very high strength concretes. Scanning electron microscopy, mercury intrusion porosimetry, thermogravimetry, water absorption and oxygen permeability tests were carried out. The results showed a low portlandite content in UH (in the order of 75% lower than in concrete C50) and a low degree of hydration, but they rise with curing temperature. These concretes have a very fine porous structure, with a high concentration of pores on the nanoscale level, below 0.05 µm. Their porosity accessible to water is consequently around 7-fold lower than in conventional (C30), 6-fold lower than in high-strength (C50) and 4-fold lower than in very high-strength (C90) concretes. Their oxygen permeability is at least one order of magnitude lower than in C90, two orders of magnitude lower than in C50 and three orders of magnitude lower than in C30. The percentage of added steel fibre does not affect the UH porous structure.
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Semberova, Jana, Karel Holada, Olga Simakova, Monique P. Gelderman-Fuhrmann und Jan Simak. „Carbon Nanotubes Activate Platelets by Facilitating Extracellular Ca2+ Influx“. Blood 112, Nr. 11 (16.11.2008): 992. http://dx.doi.org/10.1182/blood.v112.11.992.992.
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Abstract Due to a unique combination of their physico-chemical properties, carbon nanotubes (CNTs) are among the principal materials used in biomedical nanotechnologies. Superior mechanical characteristics like elasticity (CNTs 1012Pa vs. steel 108Pa) and tensile strength (CNTs 100 GPa vs. steel 2 GPa) make CNTs very attractive candidates as materials for plastic composites for various biomedical applications including devices for collection, processing, and storage of blood transfusion products. Moreover, CNTs have a profound impact on the development of diagnostic biosensors, drug delivery nanosystems, or imaging nanoprobes for intravascular use. Thus the investigation of CNT activities on platelets is a critical safety issue. We studied the effects of PBS suspensions of structurally different purified CNT materials from different manufacturers (Nanolab, NanoAmor, SES, MER) on human platelets (PLTs) and compared their effects to amorphous carbon black nanoparticles (ACB; > 99%, mean size 30 nm, Aldrich), C60 fullerene (nC60; 99.9%), fullerenol C60(OH)24 (both from MER Corp.), and NIST standard polystyrene nanobeads (PNBs; 20nm and 200nm; Duke Scientific Corp.). Using aggregometry of human platelet rich plasma (PRP), we found that CNT materials induced PLT aggregation in a concentration dependent manner. Single wall CNTs (SWCNTs) at 100 μg/mL showed PLT-aggregation 34 ± 10%, similarly to most tested multiwall CNTs (MWCNTs), which was significantly higher compared to ACB 15 ± 4%; p = 0.03. In contrast, fullerene nC60, fullerenol C60OH24, PNBs, or vehicle (PBS) did not cause any significant PLT aggregation (4 ± 0.5%; positive control collagen 100%). Interestingly, the thicker MWCNTs of d = 60nm (MWCNT60) exhibited significantly higher aggregating activity (27 ± 6%) compared to MWCNTs of d = 15nm (13 ± 3%; p = 0.007). Moreover, the bamboo structured MWCNTs showed only very low aggregating activity (7 ± 6%) compared to the corresponding hollow MWCNTs (33 ± 15%; p = 0.001). The PLT aggregation response (MA, AUC) induced by CNTs was proportional to the extracellular Ca2+concentration and was completely inhibited by 100 μM EDTA. The activation-dependent Ca2+ channel blocker SKF 96365 at 100 μM caused a significant inhibition (64 ± 16%) of MWCNT60-induced PLT-aggregation response. In contrast, no inhibitory effect on CNT-induced PLT-aggregation response was observed with 2-APB (20 μM; IP3 receptor inhibitor), NF 449 (1 μM; P2X1 blocker), MRS 2500 (5 nM; P2Y1 blocker), or TBHQ (20 μM; SERCA3 blocker). The effect of CNTs on intracellular free Ca2+ concentration [Ca2+]i was studied using a ratio fluorometry in platelets loaded with a Ca2+-sensitive probe FURA-2AM. Changes in fluorescence in individual platelets (n=100) were monitored using an epifluorescence/contrast phase microscope with a low light-level CCD camera/microphotometer assembly. We demonstrated that in contrast to ACB or PNBs, MWCNTs induced in platelets a rapid concentration dependent elevation of [Ca2+]i. For example, MWCNT60 at 100 μg/mL caused a 107 ± 4 nM increase in [Ca2+]i in platelets. No response was observed in Ca2+ free buffer. In addition, the flow cytometric analysis demonstrated that CNT-induced PLT activation led to surface exposure of CD62P and CD63 and a release of CD62P+ and CD63+ platelet membrane microparticles (MPs). In conclusion, we demonstrated that CNTs activate platelets and cause a platelet release reaction, aggregation, and release of MPs. The PLT-activating effect of CNTs is structure dependent: the hollow and thicker (60 nm) MWCNTs were most potent. A likely mechanism is that CNTs induce extracellular Ca2+ influx with involvement of activation-dependent Ca2+ channels. Our results warrant further studies on blood compatibility of CNT materials for biomedical applications. Caution needs to be applied when considering CNT materials as additives for plastics for transfusion devices and other devices that come in contact with blood. The findings and conclusions in this study have not been formally disseminated by the Food and Drug Administration and should not be construed to represent any Agency determination or policy.
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Wang, Hai Chao, Xi Quan Xu, Li Jun Zhou, Hong Ying Zhang und Feng Lian Yang. „The Experimental Study on Concrete-Filled Thin-Walled Square Steel Tube Short Columns Fixed U-Shaped Steel Bars“. Applied Mechanics and Materials 94-96 (September 2011): 962–69. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.962.
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Based on the compression characteristics of the concrete-filled thin-walled square steel tube short columns, the U-shaped tie bars are designed in this paper. The U-shaped tie bars and steel pipe walls are connected with each other in T-shape in order to enhance the local stability of the walls under pressure. According to the concrete strength C30/C35/C40 and the thickness of the steel plates 1.25mm/1.75mm/2.5mm,42 short-column specimens are made, and the size of all specimens is 200mm×200mm×690mm.The bearing capacity test is done by the 500-ton electro-hydraulic serve testing machine. The strain of U-shaped tie bar and thin-walled steel are tested, and then the whole curve of compression process is obtained. The results show that the U-shaped tie bar has a very good role in bonding, and has good effects on improving buckling mode and the ductility of the components significantly. Concrete-filled thin-walled square steel tube short column fixed U-shaped tie bar has advantages on stronger post- deformability and more applicable to configuration compared with existing research achievements, and can provide a reference for engineering design.
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Xie, Heng Yan, und Xin Zheng. „Preparation and Basic Mechanical Properties of Self-Compacting Concrete“. Advanced Materials Research 150-151 (Oktober 2010): 354–57. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.354.
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Self- compacting concrete (SCC) has characteristics of good flow-ability, non-vibrating and self-compacting. It is the optimum to be used in concrete members with densely distributed steel bar and concrete is inconvenient to be vibrated. The mixture ratio of design grade of C20 and C40 SCC commonly used in project is given after trial mix. The compression stress-strain relation of SCC prism is obtained by MTS. The Mechanical property indexes of SCC are got. The ultimate compression strain of the extreme fiber is acquired by testing beam made of SCC, and the relation between the ultimate compression strain of the extreme fiber in flexural member and the strain at the peak of the stress-strain curve subjected to uniaxial compression is given.
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Hou, Wen Qi, Mei Xin Ye und Ye Zhi Zhang. „Ultimate Bearing Capacity of Headed Studs in Tensile Concrete Slab“. Advanced Materials Research 163-167 (Dezember 2010): 11–15. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.11.
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Abstract. In the presented paper, reverse push-out test method was put forward and applied in the ultimate bearing capacity experiments of studs with concrete slab in tension. Ultimate bearing capacity experiments were carried out on 22 reverse push-out specimens composed of C50 or C40 concrete, 14MnNbq steel girder and Φ22studs. Results showed that ultimate bearing capacity of studs, pu, in tensile concrete slab is controlled by concrete failur, concrete strength, studs arragement and reinforcement ratio are the main influence factors of pu. Compared with that in compressive concrete, pu of Φ22 studs in tensile concrete is reduced about 30% averagely. According to the test results, a fitted load-slip relationship curve and a regression formula of pu for studs in tensile concrete were put forward, calculated results were in good agreement with the test results.
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Chen, Yu Hui, Yun Huang und Yao Huang. „Optimization Design for Gun-Receiver Materials Belt Grinding Based on Orthogonal Experimental Method and Grey Relational Analysis“. Advanced Materials Research 797 (September 2013): 55–60. http://dx.doi.org/10.4028/www.scientific.net/amr.797.55.
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In order to change the current situation of gun-receiver manual polishing, the paper presents a new process for abrasive belt grinding of gun-receiver material (C50 steel). Orthogonal test were conducted with abrasive belt grinding of C50 steel to do research on material removal rate and surface roughness. The best parameter combination to the optimization design which can guarantee high material removal rate and low surface roughness was obtained by using grey relational analysis method and verified by experiments. The above mentioned research not only can improve the removal rate of C50 steel, but also do help to prolong the service life of the belt. Whats more, it can guide a theoretical significance and practical value to the production practice.