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Structural Elucidation of Some Borate Glass Specimen by Employing Ultrasonic and Spectroscopic Studies  [PDF]
S. Thirumaran,N. Karthikeyan
Journal of Ceramics , 2013, DOI: 10.1155/2013/485317
Abstract: Quantitative analysis has been carried out in order to obtain more information about the structure of two glass systems, namely, (B2O3-MnO2-PbO) (BML glass system) and (B2O3-Na2CO3-P2O5) (BSP glass system). Their structural elucidation has been carried out by studying the ultrasonic velocities (longitudinal velocities and shear velocities ) and density of these glass samples. The present investigation has been interpreted by focusing more on elastic and mechanical properties of glass specimen through ultrasonic study and the elemental analysis study through spectroscopic studies. The scanning electron microscopic (SEM) study was also carried out with a view to throwing more light on their morphological aspects. The results are corroborated in the light of the role of borate (B2O3) glasses in the formation of glassy structural network. 1. Introduction The acoustical properties are particularly suitable for describing glasses as a function of composition because they give some information about both the microstructure and the dynamics of the glasses. The elastic properties are related to microscopic properties through the behavior of the network and the modifier. Attempts have been made to measure and interpret the acoustical properties of borate glasses in terms of structural changes [1–3]. Bahatti and Singh [4] discussed the composition dependence of ultrasonic velocity. The ultrasonic nondestructive testing has been found to be one of the best techniques to study the microstructure, characterization, mechanical properties, and phase changes as well as to evaluate elastic constants. One can also characterize the materials such as semiconducting glasses, superconducting glasses, glass ceramics and bioactive glasses by this nondestructive testing technique. The propagation of ultrasonic wave in solids such as glass provides valuable information regarding the solid state motion in the material. Interest in glasses has rapidly increased in recent years because of diverse applications in electronic, nuclear, solar energy and acoustooptic devices. The acoustic wave propagation in bulk glasses has been of considerable interest to understand the mechanical properties [5]. The velocity of sound is particularly suitable for characterising glasses as function of composition because it gives information about the microstructure and dynamics of glasses [6]. The study of elastic properties of the glasses has inspired many researches [7, 8] and significant information about the same has been obtained. The elastic moduli of glasses are influenced by the many physical
Ultrasonic characterisation of calcium phosphate glasses and glass-ceramics with addition of TiO2
A. V. Gayathri Devi,V. Rajendran,,N. Rajendran
International Journal of Engineering Science and Technology , 2010,
Abstract: Calcium phosphate based glasses with different concentrations of TiO2 (0 to 2.5 mol%) were prepared and their corresponding glass-ceramics were obtained by controlled heat treatments. The amorphous nature of glasses and the presence of crystalline phases in glass-ceramics were studied through XRD studies. Density, molar volume, ultrasonic velocities, attenuation, elastic constants and microhardness of glass and glass-ceramics were used to study structural and mechanical properties. The results indicate that the added TiO2 increases the cross link density of phosphate glasses and thus results in higher network stability. The glass-ceramics exhibits higher mechanicalstrength when compared with its corresponding glasses.
Comparison of Elastic Modulus and Compressive Strength of Ariadent and Harvard Polycarboxylate Cement and Vitremer Resin Modified Glass Ionomer  [cached]
Ahmadian Khoshemehr Leila,Arbabi Kalati Rasoul,Arbabi Kalati Parvin
Zahedan Journal of Research in Medical Sciences , 2009,
Abstract: Background: Luting agents are used to attach indirect restoration into or on the tooth. Poor mechanical properties of cement may be a cause of fracture of this layer and lead to caries and restoration removal. The purpose of this study was to compare the elastic modulus and compressive strength of Ariadent (A Poly) and Harvard polycarboxylate (H Poly) cements and Vitremer resin modified glass ionomer (RGl).Materials & Methods: In this experimental study 15 specimens were prepared form each experimental cement in Laboratory of Tehran Oil Refining Company. The cylindrical specimens were compressed in Instron machine after 24 hours. Elastic modulus and compressive strength were calculated from stress/strain curve of each specimen. One way ANOVA and Tukey tests were used for statistical analysis and P values<0.05 were considered to be statistically significant.Results: The mean elastic modulus and mean compressive strength were 2.2 GPa and 87.8MPa in H poly, 2.4 GPa and 56.5 MPa in A Poly, and 0.8GPa and 105.6 MPa in RGI, respectively. Statistical analysis showed that compressive strength and elastic modulus of both polycarboxylate cements were significantly different from hybrid ionomer (P<0.05), but the difference between elastic modulus of two types of polycarboxilate cements was not statistically significant. Compressive strength of two polycarboxilate cements were significantly different (P<0.05). Conclusion: An ideal lutting agent must have the best mechanical properties. Between the tested luttins RGl cement had the lowest elastic modulus and the highest compressive strength, but the A poly cement had the highest elastic modulus and the lowest compressive strength. Therefore none of them was the best.
Ultrasonic methods in diagnostics of glass-polyester composites  [PDF]
G. Wróbel,?. Wierzbicki
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: The aim of the work was to find relationship between the ultrasonic wave velocity and the strenghtand Young’s module in a glass-polyester composite.Design/methodology/approach: The experiments have been performed in three distinct phases. During the firstphase, typical glass-polyester composite was ageing to get different mechanical properties. In the second phase,strength and ultrasonic properties of composite was testing. In the last of phases we compare changes of properties.Findings: The experimental results showed relationship between velocity of ultrasonic wave and strength andYoung’s module.Research limitations/implications: In those applications, in which polymer structural composites were subjectedto a heat and mechanical load, it is essential to test the strength characteristics of the composites in the use of nondestructivemethods. That enables contemporaneous status check of the structure and makes it possible to replacethe bivalent evaluation scale (good – bad) with an incessantly gradable strength degradation scale for a material.Practical implications: The results of the investigation have shown possibility of using ultrasonic methodto diagnosis of strength changes in composites. This method allowed to test working parts of machines orbuildings, without destruction.Originality/value: The results of the investigations allow to confirm, that ultrasonics can be used to nondestructivetesting of the strength and Young’s modulus changes.
DYNA , 2011,
Abstract: the elastic mechanical behavior of elastic materials is modeled by a pair of independent constants (young's modulus and poisson's coefficient). a precise measurement for both constants is necessary in some applications, such as the quality control of mechanical elements and standard materials used for the calibration of some equipment. ultrasonic techniques have been used because wave velocity depends on the elastic properties of the propagation medium. the ultrasonic test shows better repeatability and accuracy than the tensile and indentation test. in this work, the theoretical and experimental aspects related to the ultrasonic through-transmission technique for the characterization of elastic solids is presented. furthermore, an amorphous material and some polycrystalline materials were tested. results have shown an excellent repeatability and numerical errors that are less than 3% in high-purity samples.
The effect of fiber content on the ultrasonic wave velocity in glass/polyester composites  [PDF]
G. Wróbel,S. Pawlak
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: The primary purpose of the present study was to find relationship between ultrasonic wave velocityand the fiber content in glass/polyester composites. In addition, further tests were conducted to determine howother factors can affect the ultrasonic wave velocity.Design/methodology/approach: Experimental data have been obtained using ultrasonic wave velocitymeasurements and standard destructive analysis. For ultrasonic non-destructive testing, through-transmissiontechnique was used.Findings: Experimental results have shown that the longitudinal wave velocity increases almost linearly withan increase of the fiber content in investigated specimens.Research limitations/implications: The propagation velocity of the ultrasonic waves can be affected, apartfrom fiber content, by interfacial stresses and changes of elastic modulus in polymer matrix during long-lastingconditioning. These factors overlap and which of the two can affect the ultrasonic wave to a higher degree is yetto established. Further work is needed in this area.Practical implications: Ultrasonic wave velocity measurement seems to be an effective method of fiber contentevaluation, but for any different composites, distinct relationships should be determined.Originality/value: The results obtained would be of considerable importance in industrial applications toachieve a first estimate of fiber content variations in composite materials.
Ultrasonic Measurement of Corrosion Depth Development in Concrete Exposed to Acidic Environment  [PDF]
Fan Yingfang,Hu Zhiqiang,Liu Jianglin
International Journal of Corrosion , 2012, DOI: 10.1155/2012/749185
Abstract: Corrosion depth of concrete can reflect the damage state of the load-carrying capacity and durability of the concrete structures servicing in severe environment. Ultrasonic technology was studied to evaluate the corrosion depth quantitatively. Three acidic environments with the pH level of 3.5, 2.5, and 1.5 were simulated by the mixture of sulfate and nitric acid solutions in the laboratory. 354 prism specimens with the dimension of 150?mm × 150?mm × 300?mm were prepared. The prepared specimens were first immersed in the acidic mixture for certain periods, followed by physical, mechanical, computerized tomography (CT) and ultrasonic test. Damage depths of the concrete specimen under different corrosion states were obtained from both CT and ultrasonic test. Based on the ultrasonic test, a bilinear regression model is proposed to estimate the corrosion depth. It is shown that the results achieved by ultrasonic and CT test are in good agreement with each other. Relation between the corrosion depth of concrete specimen and the mechanical indices such as mass loss, compressive strength, and elastic modulus is discussed in detail. It can be drawn that the ultrasonic test is a reliable nondestructive way to measure the damage depth of concrete exposed to acidic environment. 1. Introduction Since 1940s, pollution of acid rain has become to be a significant environmental problem confronting the environmentalists. In the past two decades, it is reported that acid rain falls have become more and more serious worldwide [1–6]. It is well known that concrete has become and will continue to be the most widely used construction material in civil engineering. However, when concrete is subject to acid rain, physical and chemical reactions occurred. The complex reactions will alter the internal structure of concrete, which will result in the change of its material property. Many famous buildings, such as Emei Mountain, Leshan Grand Buddha, Acropolis monument in Greece, and the Statue of Liberty in the United States, have been strongly damaged by acid rain in the previous decades. The damage effect of acid rain on concrete structures has attracted more and more attention of civil engineers gradually. A better understanding of the material properties of concrete exposed to acidic environment can help to discover the damage process of the in-service structures. Some experimental studies have been performed to discover the corrosion mechanism of acid rain attacking concrete, and simulation test of the acid rain attacking concrete was analyzed [7–12]. However, it is still
Joaquim Carlos Gon?alez,Ailton Teixeira do Valle,Alexandre Florian da Costa
CERNE , 2001,
Abstract: The objective of this work was to estimate wood elastic constants, applying utrasonic non destructive tests. Wood from: Fava Amargosa (Vataireopsis speciosa), Jequitiba Rosa (Cariniana micrantha), Peroba d'Agua (Rauwolfia paraensis) e Peroba Mico (Aspidosperma macrocarpum) was used. The main wood elastic constants were estimated by means of the determination of the velocities of ultrassonic propagation, based on the equation : V2 =Ei / p ; were: V – wave propagation velocity; Ei – modulus of the wood elasticity in relation to the axis (longitudinal, radial or tangential ); p – volumetric mass. Mean values obtained for ultrasonic velocity in the three wood perpendicular directions (longitudinal, radial or tangential) showed always a statiscally significant difference for the species studied, at 1% level of probability (F test). These differences in the ultrassonic waves propagation, in relation to the wood axe, are explained by the anatomic structure of the material. The ultra sonic non-destructive methodology showed to be an alternative for studying wood mechanical properties, mainly on the elastic constants determination.
An alternative ultrasonic method for measuring the elastic properties of cortical bone  [PDF]
Martine Pithioux,P. Lasaygues,P. Chabrand
Physics , 2005,
Abstract: We studied the elastic properties of bone to analyze its mechanical behavior. The basic principles of ultrasonic methods are now well established for varying isotropic media, particularly in the field of biomedical engineering. However, little progress has been made in its application to anisotropic materials. This is largely due to the complex nature of wave propagation in these media. In the present study, the theory of elastic waves is essential because it relates the elastic moduli of a material to the velocity of propagation of these waves along arbitrary directions in a solid. Transducers are generally placed in contact with the samples which are often cubes with parallel faces that are difficult to prepare. The ultrasonic method used here is original, a rough preparation of the bone is sufficient and the sample is in rotation. Moreover, to analyze heterogeneity of the structure we measure velocities in different points on the sample. The aim of the present study was to determine in vitro the anisotropic elastic properties of cortical bones. For this purpose, our method allowed measuring longitudinal and transversal velocities (CL and CT) in longitudinal (fiber direction) and radial directions (orthogonal to the fiber direction) of compact bones. Young's modulus E and Poisson's ratio ?, were then deduced from the velocities measured considering the compact bone as transversely isotropic or orthotropic. The results are in line with those of other methods.
A comparative study on viscoelastic properties of polymeric composites measured by a longitudinal free vibration non-destructive test and dynamic mechanical thermal analysis  [PDF]
Mohammad Mehdi Jalili,Amir Soheil Pirayeshfar,Seyyed Yahya Mousavi
Physics , 2015, DOI: 10.1007/s13726-012-0069-3
Abstract: In this study, viscoelastic properties of polymeric composites were investigated through a non-destructive test (NDT) method based on longitudinal free vibration. First, three different polyester composites reinforced separately with carbon, glass, and hemp fibers, as well as, one polyester composite sample reinforced with poplar wood powder were manufactured via pultrusion and hand lay-up methods, respectively. In the proposed resonant free vibration non-destructive method, each rod-shaped test specimen was hit by a hammer at one end of specimen and immediately the acoustic response of the specimen was recorded by a microphone at the other end of the sample. Subsequently, the recorded sounds were analysed using fast Fourier transform technique. Then, frequency of the first mode of vibration for each composite specimen was utilised to calculate modulus of elasticity. Further, decrement in vibration energy as a function of time was examined to obtain loss parameter (tan {\delta}) of the provided composites. Moreover, parameters (i.e., elastic modulus and tan {\delta}) were also compared with those determined by dynamic mechanical thermal analysis (DMTA). It is found that the results obtained from the examined non-destructive test method are in consistent with those measured by DMTA approach, providing reliable, accurate and quick responses.
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