Papers by Keyword: Internal Structure

Abstract: One of the methods of curing (Cured-In-Place Pipe) CIPP pipes is the curing using ultraviolet (UV) light. The main difference from common CIPP types is in the structure of the liner material. In terms of material, it is a woven fiber glass fabric which is saturated with vinyl ester or polyester resin. In general, these pipes are more resistant to chemicals and achieve higher values of flexural properties. The paper focuses on the investigation of the short-term mechanical properties using three-point bending test and structure of UV cured CIPP liners. The computed tomography (CT) was used for the analysis of CIPP internal structure and composition.

Abstract: The alkali–silica reaction (ASR) causes internal corrosion of concrete. The aim of this work is to verify the possibility of ultrasonic method in detection of concrete internal structure changes, which were initiated by the alkali-silica reaction. For this purpose, we prepared samples that contained aggregates of two types, namely one with 98% of SiO₂ content and one with a greywacke. The dependence of ultrasonic impulse propagation velocity on the changes in the structure of mortars containing aggregates from these rocks was researched. The results of this work are not unambiguous yet and therefore it is necessary to carry out more extensive investigation with using of other methods that will allow to examine changes in the internal structure of composites more detailed.

Abstract: The paper addresses the use of laser ultrasonic structuroscopy to study how weathering affects the internal structure of rocks used for facing buildings. For 1,250 hours rock samples were subjected to 150 cycles of freezing (at-20°C) and thawing in water (at +20°C) to determine their frost resistance. Also, moistened every 30 minutes, rock samples were exposed to thermal and ultraviolet radiation for 480 hours to determine their weather resistance. The frequency-dependent phase velocity and attenuation coefficient of longitudinal ultrasonic pulses in the samples were measured. It is found that the rock samples are most seriously damaged when exposed to sharp changes in temperature. As a result of freeze-thaw processes, the velocity of elastic waves decreases by 10% on average, and the attenuation coefficient increases by a factor of 1.5 in the range of 300kHz-500kHz and more than 3 times in the range of 1.0MHz-1.5MHz. The coefficient of the relative power of “structural” noise (K parameter) is introduced to characterize the degree of degradation of rock samples. The parameter K is defined as the ratio of the power of noise component in the spectrum of scattered waves to the power of reference signal. It is shown that the parameter K increases almost by a factor of 10 as a result of various weathering processes.

Abstract: X-ray micro computed tomography (Micro-CT) is a non-destructive technique that can provide information on the internal structure of materials. The purpose of micro-CT is to assess the presence of defects as well as characterizing internal structures and potential damage present in the produced part. Simple shear is an interesting deformation mechanism for woven fabric draping. The internal structure change of the carbon fibre twill fabric after shear deformation is chosen as a subject of this paper. Parameters of the mesoscopic internal structure of the woven fabric like cross section, shape, area, and middle line coordinates can be obtained from micro-CT images through image processing procedures. Details of the image data processing for sheared fabric cross sections are discussed. This paper illustrates the possibilities of micro-focus computer tomography in materials research, namely for defining geometrical properties of textile. Image processing is also used for the recognition of fibre direction in the yarns. Described methodology can be applied for determining structure of a fabric, and the results can be used for further micromechanical modelling. Identification of the fibres orientation is important for estimation of the mechanical properties of composites and can be achieved with image processing techniques.

Abstract: Digital image technology – based computer aided design for asphalt concrete is a new direction of asphalt pavement research. This paper focuses on description of research progress achieved by the author’s research institute in the direction, mainly including two-dimensional digital image technology – based research in the internal structure and volume of asphalt concrete, industrial CT-based identification of different substances in the asphalt concrete and acquisition of morphological characteristics for coarse aggregate and three-dimensional digital image technology – based virtual reconstruction of asphalt concrete and simple mechanical behavior simulation.

Abstract: We go deep into the internal structure of the Boolean functions values, and study the relationship of algebraic immunity and algebraic degree of Boolean functions with the Hamming weight with the diffusion included. Then we get some theorems which relevance together algebraic immunity, annihilators and algebraic degree of H Boolean functions by the e-derivative which is a part of the H Boolean function. Besides, we also get the results that algebraic immunity and algebraic degree of Boolean functions can be linked together by the e-derivative of H Boolean functions and so on.

Abstract: The filtration effect of automobile engine oil filter materials have two different expression index,such as nominal filtration accuracy and absolute filtration accuracy.In fact,the nominal filtration accuracy is labeled by manufacturer,however,the absolute filtration accuracy is needed experiment testing only to know.After testing the absolute filtration accuracy of these ten kinds of oil filter materials,it is turned out that there is an obvious difference between these two filtration accuracy.So this paper is based on the results of the two filtration precision and established a linear regression equation of absolute filtration accuracy=2.922+0.631×nominal filtration accuracy.If only knowing of the nominal filtration accuracy of oil filter materials,then the absolute filtration accuracy can be computed from the linear regression equation instead of experimental testing of absolute filtration accuracy.What’s more,this linear regression equation is easy and simple and has some application value and practical significance.

Abstract: The morphologies and microstructures of cornstarches with different amylose/amylopectin ratios (waxy: 0/100; maize: 23/77; Gelose 50: 50/50; Gelose 80: 80/20) were studied by a combined SEM and confocal laser scanning microscope (CLSM). CLSM allowed the visualization of cross-sections of starch granules without the need for sectioning techniques that lead to destruction of the microstructure of sample. The influence of the amylose/amylopectin ratio on the internal structures and morphologies was able to be revealed by this choice of techniques. It was found that the granules of the high-amylopectin starches were more regular in shape than those of the high-amylose starches, but the surfaces of the high-amylose starches were smoother than those of the high-amylopectin starches. The high-amylose starches (G50 and G80) were brighter than that of low-amylopectin starches (waxy and maize) under confocal laser light, and the average fluorescence intensity sequence of the granules was G80>G50>maize>waxy. Waxy and maize starches show clearly cavities and channels while G50 and G80 present bright core.

Abstract: Abstract: The characteristic of internal structure of filament wound composite is investigated by experiment in this article. Cylinders manufactured by two kinds of fiber, E-glass and carbon, and epoxy resin, are cut into several pieces along the winding direction. The sections of pieces are observed with optic microscope. The result shows that there are two kinds of structure in filament wound composite, laminate area and undulating area, consisting of interwoven fiber band in different directions. Undulating quantity is measured at a series of points along undulating fiber band; a linear model is adopted to model geometrical shape of undulation.

Abstract: Polystyrene/clay nanocomposite with organically modified montmorillonite was synthesized via emulsion polymerization. Organic styrene monomer was first intercalated into intergalley of the clay hosts, followed by a typical emulsion polymerization with surfactant and initiator. To investigate the effect of clay loading, we also prepared PS/clay nanocomposites with different clay contents. Wide angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that the emulsion polymerization of PS in the presence of clay produces partially exfoliated and intercalated nanocomposites. In order to study their rheological properties, the melt pallets of composite materials were prepared and measured via a rotational rheometer with a parallel plate geometry.