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[en] The paper presents the results of the study aimed at determining the elastoplastic properties of an Al/Cu bimetallic sheet consisting of aluminum and copper layers, which were joined by cold rolling. The values of elasticity coefficients in three orthotropic planes as well as the Kirchhoff modulus, and coefficient of internal friction in the perpendicular direction to the lamination were determined. The subjects of the analysis were also the values of limit stresses, uniform energy of elastic and plastic strain per unit volume, and coefficients of the hardening curve and normal anisotropy. The tests were carried out on bimetallic specimens with varying thicknesses of the copper layer, cut from the Al/Cu sheet in the direction of rolling and in the direction perpendicular to it. Two methods of determining the directional values of mechanical parameters were used in the tests, i.e., the uniaxial quasi-static tensile test and the dynamic acoustic resonance method. It was concluded that these methods made it possible to determine directional elastoplastic properties of the Al/Cu bimetallic sheet taking into account the variable share of components in the bimetal and the direction of cutting out specimens from cold-rolled sheet.
[en] Punta Begoña Galleries, built in 1918 and located in the municipality of Getxo (Bizkaia, Spain) have a remarkable glazed ceramic decoration, whose current state of conservation presents an advanced level of deterioration. The study of the historical cultural property is framed within a multidisciplinary project, which aims to restore, recover and improve its historical and artistic value. In this sense, the recovery of the ceramic tiles is one of the crucial points, since it involves one of the visually most notorious elements. On the surface of the tiles, different degradations were observed, being the yellowish patina, one of the most significant. In order to carry out a cleaning treatment, the nature of the patina was evaluated, whose coating is a consequence of atmospheric contamination, as the chemical analyzes showed. Furthermore, a comparison was performed among four reactants both applied in reproduced pieces and in situ. To evaluate the effectiveness of the products, a quantitative evaluation was applied by colorimetry. In addition, this work shows an interdisciplinary methodology based on the scientific method as the best guide to achieve durable, safe and effective restoration methods.
[es]Las Galerías Punta Begoña, construidas en 1918 y ubicadas en el municipio de Getxo (Bizkaia, España) poseen una destacable decoración de cerámica vidriada, cuyo actual estado de conservación presenta un avanzado nivel de deterioro. El estudio del inmueble histórico cultural está enmarcado dentro de un proyecto multidisciplinario, que tiene como fin restaurar, recuperar y mejorar su valor histórico y artístico. En este sentido, la recuperación de la cerámica es uno de los puntos más cruciales, ya que supone uno de los elementos visualmente más notorios. En la superficie de los azulejos, se observaron diferentes degradaciones, siendo la pátina amarillenta, una de las más significativas. Con el fin de llevar a cabo una limpieza de la misma, se evaluó la naturaleza de la pátina, cuya veladura es consecuencia de la contaminación atmosférica, como mostraron los análisis químicos. A continuación se llevo a cabo una comparación entre cuatro disolventes orgánicos, aplicados tanto en probeta como in situ. Para evaluar la efectividad de los reactivos, se realizó una valoración cuantitativa mediante colorimetría. Además, el presente trabajo muestra una metodología interdisciplinaria basada en el método científico como la mejor guía a seguir para lograr métodos de restauración duraderos, seguros y efectivos.
[en] This recommendation is written to improve the assessment of the in situ. Compressive strength of concrete in existing structures by combining core strength values and non-destructive measurements. Both average strength and its scatter are considered. Deriving a characteristic strength from the assessment results is not considered here. The recommendation applies for most common techniques (ultrasonic pulse velocity, rebound hammer, pull-out) but also for less common techniques (penetration test, etc.). The recommendation does not apply to situations in which no core has been taken from the existing structure and is limited to situations where NDT is combined with cores. The recommendation introduces the concept of Estimation Quality Level, corresponding to the target of assessment, and which is put in relation with the means and strategy developed for assessing concrete. The text details all steps that must be followed from the data gathering to the checking of the quality of the final estimations. For more clarity, an illustrative example is described for each step of the assessment process.
[en] Among the applications of Materials Science and Engineering carried out by the Center for Technological Applications and Nuclear Development (CEADEN) is the use of various physical techniques to support the restoration and maintenance of buildings and other work objects of historical, cultural and social interest in Havana city. The field of Defectoscopy is addressed in this paper, where the applied Nondestructive testings also contributed to restore the cultural heritage, to upgrade the structural conditions at an important sport facility in Havana, and in a greater extent, to the safety of facilities of social significance, such as amusement parks. In this regard, three examples are presented: the inspection of structures during the restoration of the City Hall in the Museum of the Havana City at the Palace of Captains General; the welded joints testing during the restoration of the lighting system and the installation of the digital screen at the Latin American Stadium in Cerro municipality; and finally, the inspection systematically performed at maintenance works to critical elements and related devices at amusement parks.
[en] Plants are constantly challenged when trying to examine hard-to-reach areas. Execution of inspections during outages, where time pressure is an issue, calls for rapid performance without compromising precision and reliability. Inside NDE of primary piping especially for smaller diameters requires dedicated solutions. Combining long-term experience in remote-operated crawlers with expert knowledge in nondestructive examination (NDE) Framatome provides various technologies for inspection of hardly accessible areas. In-pipe manipulators have several advantages for flexible application in vertical or horizontal piping including elbows. The paper will give an overview on the present in-pipe manipulator development for pipe ID 75 to 110 mm. Focus is on the capabilities and features for visual inspection (VT), eddy-current (ECT) and ultrasonic testing (UT) as well as result assessment. (author)
[en] Seven factors play a role in the quality of a weld: 1) the metals of the parts to be welded, 2) the materials brought by the welding process that will be incorporated in the weld, 3) the welding process itself, 4) welder's technical skills, 5) the welding equipment, 6) the technical referential, and 7) the regulatory referential. In nuclear industry, technical and regulatory requirements concern the first 5 factors. The aim is to reinforce the high quality of the welds and to be sure that they have been properly made following the rules of the RCC-M construction code. The RCC-M code foresees a gradation of requirements for the welds according to the safety standard of the equipment. 3 levels have been defined: N1, N2 and N3, N3 corresponding to the highest level that is applicable to the primary and secondary cooling circuits of reactors. (A.C.)
[en] Applications of additive manufacturing (AM) are diversified, but found with preponderance in the automotive, aerospace, and medical fields. The field of additive manufacturing/material 3D printing is advancing extremely fast, and covers a broad range of materials, spanning from plastics to metals, ceramics, and even to biological tissue. In the aerospace industry one of the main points of attraction is that parts with complex shapes can be built on demand while reducing the weight at the same time. The process can also aid in the fabrication of rare parts and replacement components that are no longer in production. It is commonly understood that AM parts would have different types of defects than those found in conventionally manufactured ones, while major gaps in knowledge exists in terms of the defect type, the effect-of-defect, and the critical defect size and location. One of the shortcomings is related to the lack of physical reference blocks for calibration and performance verification of proposed non-destructive evaluation (NDE) techniques. Also, there are no standards for NDE techniques as applied to AM. This article discusses how NDE could better position itself to help AM gain the trust of aerospace industry. (author)
[en] To ensure the quality of material, nondestructive testing is necessary, and radiography testing is the nondestructive technique most commonly used today. For inspection, the quality of a radiographic image is critical, and there are many image artifacts that can reduce inspection accuracies such as noise or blurring. The deterioration in spatial resolution caused by blur in both the X-ray imaging itself and the noise reduction process are particular problems. To tackle them, we implemented a non-blind deconvolution method that employs the alternating direction method of multipliers (ADMM) after noise reduction. Experimental results confirm that the proposed algorithm effectively restores edge sharpness. The 50% modulation transfer function of the restored image of a slit-camera was about 3.54 line-pairs per mm, which is about 2.5 times higher than that of the denoised image. Moreover, the edge preservation index values are about 0.82, 0.54, and 0.75 for the restored, denoised, and acquired images, respectively. Consequentially, the proposed method has the potential to increase inspection efficiency in industrial applications.
[en] One of the most important applications of gamma based NDA technique is the assay of low-density 200 L waste drums containing low/intermediate level of activity. Segmented gamma-ray scanning (SGS) is the most commonly employed technique for the assay of such heterogeneous samples. This technique accounts for the variation of matrix materials in different segments but assumes both the source and matrix to be homogeneously distributed in each segment. For situations where the radionuclide source distribution as well as matrix distribution is significantly heterogeneous, SGS technique may lead to large errors. Another advanced NDA technique to assay radioactive waste is tomographic gamma scanning (TGS). The TGS combines transmission and emission reconstructive tomography techniques in an effort to improve the accuracy of the measurement, when the radionuclide is distributed non-uniformly in a heterogeneous matrix. With this aim, an integrated segmented and tomographic gamma scanning system (ISTGS) has been designed and fabricated for the assay of alpha active waste in 200 L drum. The system can operate in both modes, SGS mode for measuring nearly homogeneous waste and in TGS mode, for measuring heterogeneous waste. It consists of a sample platform capable of translating and rotating drum. The system also consists of a highly collimated 152Eu source (7 mCi) with motorized shutter for the transmission scan, named as the transmission source assembly. Another motorized collimator system is placed in front of the detector with a length of ~44 cm and variable aperture, thereby making the system capable of being used for low as well as high count rate samples. All the collimators have been made of high purity lead (97%)