Papers by Keyword: Tomography

Abstract: Scaling in pipelines has become a major issue, resulting in creating financial losses for geothermal industries and uneven distribution of electricity in Indonesia. An automation system prototype for a mobile gamma scan tomography device has been developed to carry out scaling measurement within geothermal pipelines. This aims to preemptively address potential scaling-related issues, enhance work efficiency, and ensure the safety of workers from radiation exposure without disrupting ongoing production activities. The automation system is designed with Arduino Mega 2560 as microcontroller and radiation counter, stepper motors as actuators, NaI(Tl) scintillation detector for radiation detection, limit switch as the trigger for zero point position setup, Human-Machine Interface (HMI) display as the system interface, and microSD card to store radiation-counting data. The automation system will drive the detector and source collimator together to perform a radiation scan and counting along the pipe diameter. The radiation is scanned in 32 projections, achieved by executing translational and rotational movements. The automation system was examined through three kinds of tests: radiation-counting system test, translational movement test, and rotational movement test. The radiation-counting system test was performed by detecting radiation at 5 random points to test its stability and quality. Meanwhile, the translational and rotational movement tests were conducted by performing radiation scanning five times on each sample of the pipe diameter: 500 mm, 600 mm, and 700 mm. The results from the examination were analyzed using quantitative statistical methods: Chi square for the stability and quality of the radiation-counting system and the detector, as well as RMSE and Standard Deviation for the accuracy and precision value of the actuator. This research has successfully built an automation system prototype for a mobile gamma scan tomography device with the stability and quality of the radiation counting system falls within the acceptable range of 3.325 to 16.919 at 95% confidence level, accuracy value of 95.12% and precision value of 93.58% for its actuators.

Abstract: Typha australis is an invasive plant from Senegal also found in wetlands. In order to limit its proliferation, typha australis is used in the energy sector but also in construction. This study contributes to the valorisation of typha australis in the field of biocomposites. For this purpose, typha fibres were used. The fibres were extracted manually using a plastic comb, then subdivided into three zones, namely the bottom, middle and top, and dried. The resulting fibres were characterised physically by measuring density, water content and absorption coefficient, and morphologically by determining the morphology but also of the section of the fibres. many respects, the physical property results concerning density show an average of the three areas of 1.53 g/cm³ with a water content between 6 and 10% and an absorption coefficient showing two main absorption phases. As for the tomography results, we directly notice the presence of fibre bundles and not of individual fibres due to the manual extraction method used. Nevertheless, the results obtained suggest a behaviour comparable to that of the most commonly used natural fibres, namely flax.

Abstract: 3D imaging techniques have an enormous potential to understand the microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this conference paper we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. We demonstrate showcases of ceramics and composite materials, where microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. We present in situ analysis of the damage evolution in an Al/Al₂O₃ metal matrix composite during tensile load and the identification of void formation (different kinds of defects, particularly unsintered powder hidden in pores, and small inhomogeneity’s like cracks) in Ti64 parts produced by selective laser melting using synchrotron X-ray refraction radiography and tomography.

Abstract: The paper deals with the possibility of using two different types of fly ash contaminated by flue gas denitrification (Selective Non-Catalytic Reduction (SNCR)) as a filler into the polymer anchor based on epoxy resin. Due to the problematic use of contaminated fly ash in silicate materials, the use of such fly ash in polymer materials seems to be effective because by mixing with polymers such as polyester and epoxy resins, toxic gas ammonia (NH₃) does not release. Determination of optimal percentage of filling by the fly ash was performed in order to achieve the best possible physical and mechanical properties of the epoxy anchor material. It was found out that the 45% addition of both used of contaminated fly ashes seems to be the most appropriate, when the polymer anchor material exhibited better tensile properties than reference anchors containing quartz sand Dorsilit. Furthermore, it was found that the optimal addition of contaminated fly ash also positively influenced the maximum anchoring force found in the tug test. Detailed connection of anchor material with anchored bar and concrete was observed on tomography images.

Abstract: In this paper, we aim at characterizing three different cast iron alloys and their microstructural features, namely lamellar, compacted and nodular graphite iron. The characterization of microscopic features is essential for the development of methods to optimize the behavior of cast iron alloys; e.g. maximize thermal dissipation and/or maximize ductility while maintaining strength. The variation of these properties is commonly analyzed by metallography on two-dimensional representations of the alloy. However, more precise estimates of the morphologies and material characteristics is obtained by three-dimensional reconstruction of microstructures. The use of X-ray microtomography provides an excellent tool to generate high resolution three-dimensional microstructure images. The characteristics of the graphite constituent in the microstructure, including the size, shape and connectivity, were analyzed for the different cast iron alloys. It was observed that the lamellar and compacted graphite iron alloys have relatively large connected graphite morphologies, as opposed to ductile iron where the graphite is present as nodules. The results of the characterization for the different alloys were ultimately used to generate finite element models.

Abstract: The rapid development of new materials and their application in an extremely wide variety of research and technological fields has lead to the request of increasingly sophisticated characterization methods. In particular residual stress measurements by neutron diffraction, small angle scattering of X-rays and neutrons, as well as 3D imaging techniques with spatial resolution at the micron or even sub-micron scale, like micro-and nano-computerized tomography, have gained a great relevance in recent years.Residual stresses are autobalancing stresses existing in a free body not submitted to any external surface force. Several manufacturing processes, as well as thermal and mechanical treatments, leave residual stresses within the components. Bragg diffraction of X-rays and neutrons can be used to determine residual elastic strains (and then residual stresses by knowing the material elastic constants) in a non-destructive way. Small Angle Scattering of neutrons or X-rays, complementary to Transmission Electron Microscopy, allows the determination of structural features such as volume fraction, specific surface and size distribution of inhomogeneities embedded in a matrix, in a huge variety of materials of industrial interest. X-ray microtomography is similar to conventional Computed Tomography employed in Medicine, allowing 3D imaging of the investigated samples, but with a much higher spatial resolution, down to the sub-micron scale. Some examples of applications of the experimental techniques mentioned above are described and discussed.

Abstract: Nowadays, X-ray tomography is one of the most pertinent directions of the development of non-destructive testing methods. Besides the experimental setup to conduct the X-ray tomographic measurements, it is necessary to have stable and flexible software. In most cases, existing software packages for the reconstruction of tomographic data are not freeware. This makes tomographic experiments not flexible because of the restriction of the source code correction. This papers explains how to implement one of important parts of tomographic research, namely, experimental data simulation, which allows to test reconstruction algorithms further.

Abstract: This work presented an experimental study to observe the inside conditions and damage appearances of fiber reinforced composites material by non destructive testing (NDT) method. In order to achieve this, an open hole specimen of unidirectional glass fiber composite (GFRP) and discontinuous carbon fiber composite (DCFC) had been using as the specimen test under tensile fatigue loading and observed using post failure monitoring techniques of NDT namely computed tomography (CT) scan. The results shown that the tomography observation based on segmentation method of gray value gives a good detection on early damage appearances before final failure of GFRP and DCFC after tensile fatigue loading conditions.

Abstract: The work explores feasibility of 3D finite element modeling (FEM) to study the effective linear properties of porous brittle material microstructures represented by a uniform cubic mesh. Both artificial virtually generated and real 3D tomography specimens are considered in this work. A method for assessment of the critical value of tomography resolution is proposed. A method to build approximations of the linear effective structure properties of interest at virtually zero FE size is developed. The methods do not have to be associated with mechanical modeling only but can be applied in some other cases, e.g. effective thermal conductivity or effective permeability calculations.

Abstract: This paper is a study of cross-sectional imaging of a specimen with gamma transmission tomography system. The aim of this paper is to create the cross-section image of a warhead specimen with the gamma transmission tomography system for inspection the air gaps, cracks find them from the specimen. The compositions of specimen are including cylindrical steel , steel balls ,rubber and plaster. The steel balls are formed in the cylindrical steel and explosive is replaced by plaster. Two holes and a rectangle shape are formed in the plaster. The results from cross-section image from the reconstruction shows holes but the thin rectangle shape is invisible.