Papers by Keyword: Density

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Authors: Jan Pošta, Jakub Dolejs, Lubomír Vítek
Abstract: Structural timber is a traditional construction material. Timber structures belong to essential parts of almost all historical buildings, especially roof and ceiling structures. Their actual condition affects durability of the whole building, therefore it is necessary to check the conditions of the structure regularly and take care of possible undesirable changes. If these structures have historical value we have to use non-destructive or semi-destructive methods during this investigation. Penetration methods in combination with ultrasonic method are used nowadays [. Penetration devices are suitable to determine the density, surface and internal biological degradation, growth defects and moisture content of the element. The density and the velocity of ultrasonic wave represent input information to derive dynamical modulus of elasticity. Penetration devices work on the principle of measuring the depth of penetration of a steel tip or on the principle of resistance drilling. Another method of determining the density of inbuilt element is the radial core. These methods are semi-destructive. It is the subject matter of the authors research to replace these penetration methods by radiometric measure of mass density. This method is based on the principle of gamma rays dispersion or on the principle of gamma rays absorption in a timber element. Radiometry as a measurement of density is often used for concrete constructions and asphalt pavement now. This measurement can be applied to the inbuilt elements, which is its a main advantage.
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Authors: Ying Liao, Wei Xu Hao
Abstract: Wireless sensor networks (WSNs) detect and monitor the outside physical state by the sensor nodes organizing automatically. Utilizing clustering algorithm to form hierarchical network topology is the common method which implements managing network and aggregating data in WSNs. Different from the previous clustering algorithms, this article proposes a clustering algorithm for WSNs based on distance and distribution to generate clusters considering residual energy of nods in WSNs with inhomogeneous distribution. The simulation result indicates that the algorithm can establish more balanceable clustering structure effectively and enhance the network life cycle obviously.
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Authors: Hyun Rok Cha, K.S. Lee, Cheol Ho Yun, Hyeon Taek Son, Tea Uk Jung
Abstract: In this paper, we suggested the new standards of motor design in using of Soft magnetic composite (SMC) material. Previous motor design in using of SMC material executed the same procedures of silicon steel. These procedures assumed that all places of material have the same density distribution and B-H curves. But we showed that the SMC material has inequality density distribution. By using powder forming analysis with FEM analysis, we showed that difference of density distribution could not be avoided because of the shear stress on powder, surface of the mold and punch. Therefore the magnetic characteristic was not the same in all places of material. So, we suggested the new method of motor design which considered the inequality density distribution in using of SMC material. And we compared previous method results and new method results and showed the differences of the result values. The density deviation of the SMC motor core was 5.8% and efficiency deviation was 3%. Especially the output value was different above 11% when we got the results by using previous method.
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Authors: E.S. Gorkunov
Abstract: The effect of plastic tensile deformation on changes in density and magnetic behaviour has been studied on low-carbon steel specimens under hydrostatic pressure of 0.1 to 500 MPa in a test chamber. It has been shown that the parameters of minor magnetic hysteresis loops can be used to estimate the amount of plastic strain and the strain-related structural damage of metal.
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Authors: Zheng Dong Li, Qiang Guo, Yin Xu He, Ke Tu, Yi Wei
Abstract: Gas monitor system based on wireless sensor network technology and ZigBee overtakes the limitation of traditional system that the situation in mine is unknown in time. With this system, the security manager can real-time monitor the gas density of multi-location .Compared with traditional system, this system is portable and extensible and it also has advantage of physical size and power consumption. This paper describes both the whole system architecture and the structure of single node. The results show that the system is safe, stable and guarantee the security of miners.
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Authors: Souad A.M. Al-Bat’hi, Souad A.M. AlBat’hi, Yose Fachmi Buys, Muhammad Hazwan Hadzari, Maizatulnisa Othman
Abstract: Nowadays, people have built mega-watt scales of wind turbines to generate electricity from wind energy. These big scales of wind turbine blade need lighter materials in order to optimize the generation of electricity. Due to this issue, purpose of this paper is to find a light material which is suitable to be used in making wind turbine blades. The use of natural fiber as a reinforcement agent in composite seems to have a big potential as natural fibers show desired characteristic needed for wind turbine blades' material. In this research, rice straw fiber was used as reinforced agent in composite with polypropylene as matrix. The composite produced was then characterized by mechanical testing which include tensile, flexural and impact as well as density measurement, dynamic mechanical testing (DMA) and Scanning Electron Microscopy (SEM). From the result obtained, it is found that the introduction of rice straw fiber to polypropylene matrix able improve the mechanical properties of the composite. The results of the composite obtained were then compared with current materials used.
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Authors: En Yang Wang, Masaki Omiya
Abstract: A Microscopic Study on Local Strain Rate Sensitivity of Polypropylene Syntactic Foam with Microballoons
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Authors: Long Shi Peng, Min Gong, Lan Qiao
Abstract: The gross volume density of mix asphalt material compacted specimen is a crucial indicator in the design of asphalt mixture and quality control of asphalt pavement, and it directly determines the asphalt aggregate ratio and the degree of compaction. It has a great practical significance to distinguish and choose the test method of gross volume density correctly. The specific aspects of the methods to determine gross volume density have been controversial. A new method named brush wax method is put forward for these issues. The density, priority, VMA and compactness of asphalt mixture were measured by different methods in the tests. By comparison of the new method and the other methods, the main technical indexes of asphalt mixture obtained by the brush wax method are the only one which greatly satisfies the technical requirements.
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Authors: Rong Lin Chen, Zhi Xing Zeng, Ke Min Zhou
Abstract: This paper is an overview of research about the concrete with expanded polystyrene beads as its aggregate in the past. First, a brief introduction to the expanded polystyrene beads concrete is given. Then, the researches of these years is presented and discussed, and the important studies are described in detail. Finally, the paper gives a summary of the research status and prospects of expanded polystyrene beads concrete.
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Authors: Parnuwat Chimalawong, Jakrapong Kaewkhao, Keerati Kirdsiri, Pichet Limsuwan
Abstract: Soda-lime-silicate glasses in the compositions of (65-x)SiO2-25Na2O-10CaO-xHo2O3 (where x = 0.0, 0.50, 1.00, 1.50, 2.00 and 2.50 mol % ) were prepared by melt-quenching technique and characterized. The results show that, the absorption spectra of Ho3+ doped in soda-lime-silicate glass correspond with several bands, which are assigned from the ground state, 5I8 to 3H6 (360 nm), 5G4 (380 nm), 5G5 (417 nm), 5G6 (453 nm), 5F3 (479 nm), 5F4 (538 nm), 5F5 (639 nm), and 5I5 (880 nm). The refractive index and density of glasses were increase with increasing of Ho2O3 concentration. The color of glass samples is light amber with doped Ho2O3 in glass matrix.
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