Absorbing and Mechanical Properties of Cement-Based Composites with Nano-Titanic Oxide Absorbent

2010 ◽  
Vol 177 ◽  
pp. 558-561 ◽  
Author(s):  
Guo Xuan Xiong ◽  
Min Deng ◽  
Hai Qing Huang ◽  
Ming Shu Tang
Keyword(s):  
Mechanical Properties ◽  
Electromagnetic Wave ◽  
Portland Cement ◽  
Titanium Oxide ◽  
Cement Paste ◽  
Frequency Range ◽  
Absorbing Materials ◽  
Relationship Of ◽  
The Relationship

The cement-based composite absorbing materials was made of portland cement and nano-titanic oxide absorbent. The relationship of electromagnetic wave reflectivity and nanometer TiO2 contents, dispersed means, samples thickness, and effect of nanometer titanium oxide on mechanical properties of cement-based composites were discussed in details. The experiment results revealed: 1) The reflectivity of cement-based composites with nanometer titanium oxide is less than -7 dB at 8~18 GHz frequency range; 2) The least reflectivity is -16.34 dB at 16.24 GHz and the bandwidth for -10 dB is 4.5 GHz; 3) The mechanical properties of cement-based composites with nanometer titanium oxide are superior to that of cement paste.

scholarly journals The Development of Snow and Glacier Research in Switzerland

1948 ◽  
Vol 1 (04) ◽  
pp. 192-201 ◽  
Author(s):  
R. Haefeli
Keyword(s):  
Mechanical Properties ◽  
Snow Cover ◽  
Laboratory Experiments ◽  
Relationship Of ◽  
The Relationship ◽  
Research Institute

The evolution of snow and glacier research in Switzerland is outlined. The settling, creep, viscosity and slipping of the snow cover are discussed in detail and the relationship of these comparatively simple processes to the more complex movements in a glacier are described. The importance of further research in glacier physics in connection with the crystallographic and mechanical properties of ice is stressed; certain preliminary laboratory experiments and some subjects for further research in the field are suggested. The Great Aletsch Glacier is recommended for this owing to the proximity of the Jungfraujoch Research Institute and facilities for transport by the Jungfraujoch Railway.

The Influence of Pore-Strucrure on the Campressive Strength of Hardened Cement Paste

1984 ◽  
Vol 42 ◽  
Author(s):  
Huang Yiun-Yuan ◽  
Ding Wei ◽  
Lu Ping
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cement Paste ◽  
Total Porosity ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
New Information ◽  
The Relationship ◽  
Empirical Constants

AbstractThe pore-structure strongly influences the carpressive strength of hardened cement paste (hcp) and other porous materials, as well as other mechanical properties. The simplest but most currently used expression representing the relationship between the pore-structure and compressive strength is fram Balshin: σ = σ0 (l-P)A, in which only the total porosity P is involved as a single parameter and σ0 and A are empirical constants. The influence of pore size distribution and pore shapes etc. are not considered.The authors introduce second parameter w - the factor of relative specific surface area of the pores other than the total porosity P into consideration and a new expression is proposed:σc=K11-p/1+2p(K2(1-p))K3w+K4 all the constants K1 - K4 can be determined experimentally. By using of this expression the new information relating the influence of pore-structure on the caopressive strength of hcp can be predicted.

The Effect of Boron and its Compounds on Setting of Portland Cement

2014 ◽  
Vol 1000 ◽  
pp. 16-19 ◽  
Author(s):  
Jiří Kratochvíl ◽  
Tomáš Opravil ◽  
Pavel Diviš
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Portland Cement ◽  
Boric Acid ◽  
Cement Paste ◽  
Kinetics Of

The aim of this work is to study the influence of boron and its compounds, boric acid and borax, on the hydration of Portland cement. The samples – cement paste modified by the addition of boron, borax and boric acid in different concentrations were prepared. The results are obtained from the evaluation of calorimetric curves, mechanical properties and phase composition. The goal is to describe the kinetics of targeted retarded process of hydration and to find such addition which would suspend the setting of boron modified system entirely. The comparison of effects of each boron-containing compound is based on its concentration and on its kind.

Experimental Study on the Performance and Microstructure of Rubberized Lightweight Aggregate Concrete

2012 ◽  
Vol 28 (4) ◽  
pp. 147-156 ◽  
Author(s):  
Guiming Wang ◽  
Bin Zhang ◽  
Zhonghe Shui ◽  
Daoyi Tang ◽  
Yun Kong
Keyword(s):  
Mechanical Properties ◽  
Cement Paste ◽  
Lightweight Aggregate ◽  
Crumb Rubber ◽  
Bonding Interface ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Micro Level ◽  
Airport Runway ◽  
The Relationship

It is of great significance to improve the flexibility of concrete for specific applications, such as a tunnel pavement or an airport runway. This paper presents the structural properties of the rubberized lightweight aggregate concrete at the macro- and micro-level. The relationship between mechanical properties and microstructure features was further explored. An experimental programme was developed to use crumb rubber and shale ceramsite to produce a flexible concrete. Much attention was paid to the influence of the crumb rubber dosage. The compressive strength and elastic modulus of the rubberized lightweight aggregate concrete were measured. Furthermore, the corresponding microstructure was evaluated by microhardness assessment and microscopic observation. Experimental results show that with the increase of crumb rubber dosage, the bonding interface between the rubber and cement paste, as well as between the shale ceramsite and cement paste, gradually became weakened or flexible. In addition, the width of the weak bonding interface became wider. As a result the flexibility of lightweight aggregate concrete can be effectively improved by correctly adjusting the crumb rubber dosage.

Effect of Sintering Temperature on Microstructure and Properties of VС/Fe Composite

2012 ◽  
Vol 430-432 ◽  
pp. 978-983
Author(s):  
Guo Jun Zhang ◽  
Zhi Ping Sun ◽  
Li Yan Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Sintering Temperature ◽  
Growth Trend ◽  
Flexure Strength ◽  
Microstructure And Properties ◽  
Whole Process ◽  
Relationship Of ◽  
The Relationship ◽  
Composite Samples

VC/Fe composite samples were fabricated by sintering at 1050, 1100 and 1150°C in vacuum. The microstructure and mechanical properties of samples were examined, and the relationship of structure and mechanical properties for VC/Fe composite sintered at different temperature were studied. The results show that fracture toughness, hardness and density is increasing obviously at 1050-1100°Cwith the increasing sintering temperature, but the growth trend increases slowly at 1100-1150°C; in whole process with temperature increased, Flexure strength heighten trend obviously. The microstructure of VC/Fe composite changed from particles piled up together to the microstructure particles closely, VC particles set gradually into Fe with temperature increased, and the gap reduced gradually.

Electromagnetic Wave Shielding and Fire Retardant Multifunctional Polymer Composites

2008 ◽  
Vol 47-50 ◽  
pp. 77-80 ◽  
Author(s):  
Vitaliy G. Shevchenko ◽  
Vladimir P. Volkov ◽  
Alexander N. Zelenetsky ◽  
Anatoliy T. Ponomarenko ◽  
Oleg Figovsky
Keyword(s):  
Mechanical Properties ◽  
Electromagnetic Wave ◽  
Wave Reflection ◽  
Fire Retardant ◽  
Polymeric Composites ◽  
Thermal And Mechanical Properties ◽  
Frequency Range ◽  
Flame Resistance ◽  
Composites Materials ◽  
Set Up

Novel PE- and PP-based electromagnetic wave shielding and absorbing materials with low combustibility, enhanced thermal and mechanical properties, containing graphite, grinded wood and fire retardants, were developed and investigated. Their flame-resistance, thermal and mechanical properties are investigated. Electromagnetic wave reflection coefficients of the materials over the frequency range 20-40 GHz were measured; despite low concentration (10%) of functional filler, reflection coefficient can be as low as -15 dB. Criteria of incombustibility of polymeric composites are formulated: thermochemical, kinetic, thermal, physical and mass transfer. These criteria allowed to set up the principles of decreasing combustibility of polymeric composites. Materials requirements, allowing to choose the most effective shielding and fireproof systems for multicomponent composites, containing polymers, wood and other fillers, were formulated.

Nylon 66 / Nomex Composite Yarn Performance Analysis

2014 ◽  
Vol 568-570 ◽  
pp. 1671-1674
Author(s):  
Gen Yang Cao ◽  
Dan Sheng ◽  
Kai Yang ◽  
Xue Feng Lu ◽  
Wei Lin Xu
Keyword(s):  
Mechanical Properties ◽  
Cluster Analysis ◽  
Performance Analysis ◽  
Confidence Interval ◽  
Polyamide 66 ◽  
Nylon 66 ◽  
Composite Yarn ◽  
Significant Difference ◽  
Relationship Of ◽  
The Relationship

The embedded composite spinning technology was applied in spinning the composite yarn of polyamide 66 and nomex .The relationship of the polyamide 66 and nomex’s content with the mechanical properties of composite yarn and hairiness was discussed. The method of cluster analysis was applied in analyzing the four kinds of yarn’s mechanical properties. And the results show that when the confidence interval is 95%, the significance of two kinds yarns were greater than 0.05. There is no significant difference between the programs. While the analysis of the hairiness data showed that the fourth solution’s harmful hairiness was much lower that the first solution’s. Therefore, the best solution is the fourth solution.

Evaluation of Grinding Performance by Mechanical Properties of Super Abrasive Wheel - Evaluation of Grade by Grinding Force

2015 ◽  
Vol 656-657 ◽  
pp. 266-270 ◽  
Author(s):  
Takekazu Sawa ◽  
Naohiro Nishikawa ◽  
Yasushi Ikuse
Keyword(s):  
Mechanical Properties ◽  
Evaluation Method ◽  
Bending Strength ◽  
Diamond Wheel ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Abrasive Wheel ◽  
Grinding Performance ◽  
Relationship Of ◽  
The Relationship

There is the grade as one of the selection criteria of a grinding wheel like WA whetstone or GC whetstone. The grade of grinding wheel is defined as an index which shows the strength of connection of a grain and a grain, and is usually estimated by bending strength. There are many papers about the relationship between the grade of a grinding wheel and the grinding performance. And, the relationship between the grade of a grinding wheel and the grinding performance is almost clear. Also, the relationship between mechanical properties of a grinding wheel and the grade is also clear. On the other hand, since the grain layer of a super abrasive grinding wheel is thin, it is difficult to apply the conventional evaluation test of the grade. And, the evaluation method of the grade which can be adapted the super abrasive grinding wheel is not established. In addition, since the grade of a super abrasive grinding wheel is a manufacture manufacturer's original standard, there is a minute difference by manufacturer. The super abrasive grinding wheel as well as the grinding wheel is conjectured that the grade influences the grinding performance. Namely, it is important to relate the grade and the mechanical properties of a grain layer. However, researches which relate the grade, the grinding performance and the mechanical properties of a super abrasive grinding wheel are not done so far. Therefore, this study examined the relationship between the mechanical properties of a grain layer of a super abrasive grinding wheel and the grade, the grinding performance. The final objective of this study is to evaluate the grinding performance from mechanical properties of a grain layer of a super abrasive grinding wheel. The purpose of this report is to clarify relationship between the grade and the grinding force in a resinoid bond diamond wheel. The specific experiment procedure is as follows. When carrying out surface grinding of the diamond sticks using a grinding wheel, the relationship of the grade and the grinding force was clarified. And based on the knowledge acquired in this experiment, relationship between the grade of a super abrasive grinding wheel and the grinding force was considered. As the results, it confirmed that the grade of a resinoid bond diamond wheel could be evaluated by the grinding force.

The Noise Characteristics Research in Subway Cars

2014 ◽  
Vol 1051 ◽  
pp. 431-434
Author(s):  
Jian Hui Tian ◽  
Lian Jian ◽  
Bing Li
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Noise Spectrum ◽  
Frequency Range ◽  
Noise Characteristics ◽  
Spectrum Distribution ◽  
Spectrum Characteristics ◽  
Relationship Of ◽  
The Relationship

The noise of different points in four sections of Shenzhen subway was tested by this paper. Real-time SPL and noise spectrum distribution curves at bogie were given, while the equivalent SPL curve was also shown. The relationship of subway speed and noise SPL was investigated. The regular of noise spectrum characteristics and SPL was obtained. The results show that the noise SPL increases with the increase of the speed. Looking from the frequency range, the frequency corresponding to larger noise SPL amplitude mainly concentrates in the lower frequency while the subway stopping, the frequency corresponding to larger noise SPL amplitude mainly concentrates in high frequency while the subway running.

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