Papers by Keyword: X-Ray Method

Abstract: This paper is an investigation of the humidity behavior of clay according to the design of historical monuments related to different dynasties in Morocco and classified as a world cultural heritage by UNESCO. The first step consisted of a diagnosis of the capillarity behavior of different design wall’s dynasties’. The second step consisted of a comparison of the humidity behavior of clay according to a different kind of the wall’s design located in Rabat as c and Fez as a dry and continental climate cities built by those dynasties’ Al Mohade and Alaouite. The method X-Ray was used for the identification of the material studied and samples were produced to analyze the humidity behavior of walls, according to their design: full walls or hollowed ones. Results indicate that the hallowed walls loosed water quickly in a very short time doesn’t exceed five days, however, the full ones keep water until the tenth day. According to the results authors’ advice on the manner of preservation of historical monuments to increase their lifetime.

Abstract: Nowadays, one of the most crucial focus in the aluminium-foundry sector is the production of high-quality castings. Mainly, High-Pressure Die Casting (HPDC) is broadly adopted, since by this process is possible to realize aluminium castings with thin walls and high specific mechanical properties. On the other hand, this casting process may cause tensile states into the castings, namely residual stresses. Residual stresses may strongly affect the life of the product causing premature failure of the casting. Various methods can assess these tensile states, but the non-destructive X-Ray method is the most commonly adopted. Namely, in this work, the residual stress analysis has been performed through Sinto-Pulstec μ-X360s. Detailed measurements have been done on powertrain components realized in aluminium alloy EN AC 46000 through HPDC processes to understand and prevent dangerous residual stress state into the aluminium castings. Furthermore, a comparison with stresses induced by Rheocasting processes is underway. In fact, it is well known that Semi-Solid metal forming combines the advantages of casting and forging, solving safety and environmental problems and possibly even the residual stress state can be positively affected.

Abstract: The residual stress on X groove welding plate of high performance bridge steel 4MnNbq is analyzed. The X-ray diffraction method, hole drilling method and indentation method are respectively used to test the residual stress on welding line, heat-affected zone and base metal. The longitudinal and transversal residual stress are analyzed and compared. The results show that the stress along welding line direction is far larger than the transversal one and the stress on base metal are comparatively smaller than the welding line. The testing results of three methods match well, while the results of X-ray method and hole drilling method are much closer, the relative error of indentation method is comparatively larger.

Abstract: In this paper a typical box beam structure on certain high speed power car was taken as study object, Based on the finite element analysis software SYSWELD, established the material parameters database for SMA490BW weathering steel, and performed the numerical simulation for the welding of typical box beam structure of side beam of high speed bogie, comparison between the simulation results and that of experiment test verified the existing welding procedures. For the purpose of studying the influence of welding sequence on the residual stress and providing theoretical support for actual production, the residual stress under different welding sequences was investigated then.

Abstract: In this study, ferroelectric materials with Bi-layered structure BaBi2Nb2O9 with excess x wt% Bi2O3 (x=0, 1.5, and 3) are investigated as the main compositions, and the sintering is proceeded from 1000oC~1100oC. The effect of Bi2O3 on the morphologies, crystal structure, and dielectric characteristics of BaBi2Nb2O9 ceramics is developed with the aid of SEM, X-ray diffraction, and dielectric-temperature curves. Dielectric properties are investigated in the temperature of 25oC~ 465oC at frequency 10KHz~1MHz. It is found that sintering temperature and Bi2O3 content has no apparent influence on the Curie temperatures, but they have large influence on the maximum dielectric constants.

Abstract: Our efforts were directed to the preparation of bismuth titanate – Bi4Ti3O12 (BIT) by mechanically assisted synthesis. The mechanical activation was applied to prepare bismuth titanate, Bi4Ti3O12, from bismuth oxide, Bi2O3, and titanium oxide, TiO2 (in an anatase crystal form). Mechanochemical synthesis was performed in a planetary ball mill in air atmosphere. Bismuth titanate ceramics was obtained by sintering at 1000 oC. The formation of Bi4Ti3O12 in the sintered samples was confirmed by X-ray diffraction analysis. Scanning electron microscopy, SEM, was used to study the particle size and powder morphology. The obtained results indicate that Bi4Ti3O12 from the powder synthesized by high-energy ball milling exhibits good sinterability, showing advantage of the mechanochemical process over conventional solid-state reaction.

Abstract: Ceramic compound with the formula BaLi2Ti6O14 was prepared by sol-gel method at basic conditions, using ammonium hydroxide as hydrolysis catalyst. Some portions of gel sample obtained were heat treated at 200, 400, 600, and 800°C. Samples were characterized by X-ray diffraction (XRD), thermal analysis (DTA-TGA), UV-Vis and FTIR. Crystalline phase was formed when a sample was treated at 800°C for 6h. This material has been previously synthesized by solid state reaction using temperatures as high as 900-1150°C for 2 to 10 days. The crystal structure of BaLi2Ti6O14 is similar to that corresponding strontium containing phase, SrLi2Ti6O14, which has been reported as catalyst for oxidative dehydrogenation of lower alkanes.

Abstract: We have investigated the ferroelectric and electrical properties of PZT 40/60 films on the bottom La_1/2Sr_1/2CoO₃(LSCO) electrode. The LSCO bottom electrode was sputtered on the SiO₂/Si(100). As the annealing temperature of PZT capacitors on the LSCO is increased, the ferroelectric properties gradually increase with the annealing temperature up to 650°C. However, for the PZT capacitors annealed above 650°C, electrical measurement cannot be performed.