Search results for: event element

Authors: Elyas Palantei, Dewiani, Farid Armin, Ardiansyah

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High precision of printed microwave sensor utilized for sensing and monitoring the potential breast cancer existed in women breast tissue was optimally computed. The single element of UWB printed sensor that successfully modeled through several numerical optimizations was multiple fabricated and incorporated with woman bra to form the spherical sensors array. One sample of UWB microwave sensor obtained through the numerical computation and optimization was chosen to be fabricated. In overall, the spherical sensors array consists of twelve stair patch structures, and each element was individually measured to characterize its electrical properties, especially the return loss parameter. The comparison of S11 profiles of all UWB sensor elements is discussed. The constructed UWB sensor is well verified using HFSS programming, CST programming, and experimental measurement. Numerically, both HFSS and CST confirmed the potential operation bandwidth of UWB sensor is more or less 4.5 GHz. However, the measured bandwidth provided is about 1.2 GHz due to the technical difficulties existed during the manufacturing step. The configuration of UWB microwave sensing and monitoring system implemented consists of 12 element UWB printed sensors, vector network analyzer (VNA) to perform as the transceiver and signal processing part, the PC Desktop/Laptop acting as the image processing and displaying unit. In practice, all the reflected power collected from whole surface of artificial breast model are grouped into several numbers of pixel color classes positioned on the corresponding row and column (pixel number). The total number of power pixels applied in 2D-imaging process was specified to 100 pixels (or the power distribution pixels dimension 10x10). This was determined by considering the total area of breast phantom of average Asian women breast size and synchronizing with the single UWB sensor physical dimension. The interesting microwave imaging results were plotted and together with some technical problems arisen on developing the breast sensing and monitoring system are examined in the paper.

Keywords: UWB sensor, UWB microwave imaging, spherical array, breast cancer monitoring, 2D-medical imaging

Procedia PDF Downloads 194

Authors: M. Amparo Nunez-Andres, Nieves Lantada

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One of the most harmful geological risks is rockfalls. They cause both economic lost, damaged in buildings and infrastructures, and personal ones. Therefore, in order to estimate the risk of the exposed elements, it is necessary to know the mechanism of this kind of events, since the characteristics of the rock walls, to the propagation of fragments generated by the initial detached rock mass. In the framework of the research RockModels project, several inventories of rockfalls were carried out along the northeast of the Spanish peninsula and the Mallorca island. These inventories have general information about the events, although the important fact is that they contained detailed information about fragmentation. Specifically, the IBSD (Insitu Block Size Distribution) is obtained by photogrammetry from drone or TLS (Terrestrial Laser Scanner) and the RBSD (Rock Block Size Distribution) from the volume of the fragment in the deposit measured by hand. In order to share all this information with other scientists, engineers, members of civil protection, and stakeholders, it is necessary a platform accessible from the internet and following interoperable standards. In all the process, open-software have been used: PostGIS 2.1., Geoserver, and OpenLayers library. In the first step, a spatial database was implemented to manage all the information. We have used the data specifications of INSPIRE for natural risks adding specific and detailed data about fragmentation distribution. The next step was to develop a WMS with Geoserver. A previous phase was the creation of several views in PostGIS to show the information at different scales of visualization and with different degrees of detail. In the first view, the sites are identified with a point, and basic information about the rockfall event is facilitated. In the next level of zoom, at medium scale, the convex hull of the rockfall appears with its real shape and the source of the event and fragments are represented by symbols. The queries at this level offer a major detail about the movement. Eventually, the third level shows all elements: deposit, source, and blocks, in their real size, if it is possible, and in their real localization. The last task was the publication of all information in a web mapping site (www.rockdb.upc.edu) with data classified by levels using libraries in JavaScript as OpenLayers.

Keywords: geological risk, web mapping, WMS, rockfalls

Procedia PDF Downloads 160

Authors: Veronique Jubera, Guillaume Salek, Manuel Gaudon, Alain Garcia, Alain Demourgues

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Luminescence of transition metal and rare earth elements cover ultraviolet to far infrared wavelengths. Applications of phosphors are numerous. One can cite lighting, sensing, laser, energy, medical or military applications. But regarding each domain, specific criteria are required and they can be achieved with a strong control of the chemical composition. Emission of doped materials can be tailored with modifications of the local environment of the cations. For instance, the increase of the crystal field effect shifts the divalent manganese radiative transitions from the green to the red color. External factor as heat-treatment can induce changes of the doping element location or modify the unit cell crystalline symmetry. By controlling carefully the synthesis route, it is possible to initiate emission shift and to establish the thermal history of a compound. We propose to demonstrate through the luminescence of divalent manganese and trivalent rare earth doped oxide, that it is possible to follow the thermal history of a material. After optimization of the synthesis route, structural and optical properties are discussed. Finally, thermal calibration graphs are successfully established on these doped compounds. This makes these materials promising probe for thermal sensing.

Keywords: emission, thermal sensing, transition metal, rare eath element

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Authors: Jakub Bartus

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In general, composite steel and concrete structures present an effective structural solution utilizing full potential of both materials. As they have a numerous advantages on the construction side, they can reduce greatly the overall cost of construction, which is the main objective of the last decade, highlighted by the current economic and social crisis. The study represents not only an analysis of composite beams’ behaviour having web openings but emphasizes the influence of these openings on the total strain distribution at the level of steel bottom flange as well. The major investigation was focused on a change of structural performance with respect to various layouts of openings. Examining this structural modification, an improvement of load carrying capacity of composite beams was a prime object. The study is devided into analytical and numerical part. The analytical part served as an initial step into the design process of composite beam samples, in which optimal dimensions and specific levels of utilization in individual stress states were taken into account. The numerical part covered description of imposed structural issue in a form of a finite element model (FEM) using strut and shell elements accounting for material non-linearities. As an outcome, a number of conclusions were drawn describing and explaining an effect of web opening presence on the structural performance of composite beams.

Keywords: composite beam, web opening, steel flange, totalstrain, finite element analysis

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Authors: Yasir Alotaibi

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The aim of this paper is to discuss the syntactic analysis of aspectual or phasal verbs in Modern Standard Arabic (MSA). Aspectual or phasal verbs refer to a class of verbs that require a verbal complement and denote the inception, duration, termination ...etc. of a state or event. This paper will discuss two groups of aspectual verbs in MSA. The first group includes verbs such as ̆gacala, tafiqa, ?akhatha, ?ansha?a, sharaca and bada?a and these verbs are used to denote the inception of an event. The second group includes verbs such as ?awshaka, kaada and karaba and the meaning of these verbs is equivalent to be near/almost . The following examples illustrate the use of the verb bada?a ‘begin’ which is from the first group: a. saalim-un bada?a yuthaakiru. Salem-NOM begin.PFV.3SGM study.IPFV.3SGM ‘Salem began to study’ b.*saalim-un bada?a ?an yuthaakiru. Salem-NOM begin.PFV.3SGM COMP study.IPFV.3SGM ‘Salem began to study’ The example in (1a) is grammatical because the aspectual verb is used with a verbal complement that is not introduced by a complementizer. In contrast, example (1b) is not grammatical because the verbal complement is introduced by the complementizer ?an ‘that’. In contrast, the following examples illustrate the use of the verb kaada ‘be almost’ which is from the second group. However, the two examples are grammatical and this means that the verbal complement of this verb can be without (as in example (2a)) or with ( as in example (2b)) a complementizer. (2) a. saalim-un kaada yuthaakiru. Salem-NOM be.almost.PFV.3SGM study.IPFV.3SGM ‘Salem was almost to study’ b. saalim-un kaada ?an yuthaakiru. Salem-NOM be.almost.PFV.3SGM COMP study.IPFV.3SGM ‘Salem was almost to study’ The salient properties of this class of verbs are that they require a verbal complement, there is no a complementizer that can introduce the complement with the first group while it is possible with the second and the aspectual verb and the embedded verb share and agree with the same subject. To the best of knowledge, aspectual verbs in MSA are discussed in traditional grammar only and have not been studied in modern syntactic theories. This paper will consider the analysis of aspectual verbs in MSA within the Lexical Functional Grammar (LFG) framework. It will use some evidence such as modifier or negation to find out whether these verbs have PRED values and head their f-structures or they form complex predicates with their complements. If aspectual verbs show the properties of heads, then the paper will explore what kind of heads they are. In particular, they should be raising or control verbs. The paper will use some tests such as agreement, selectional restrictions...etc. to find out what kind of verbs they are.

Keywords: aspectual verbs, biclausal, monoclausal, raising

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Authors: Mohamed M. El-heweity, Ahmed Shamel Fahmy, Mostafa Shawky, Ahmed Sherif

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Cold-formed steel (CFS) lipped channel sections are popular as load-bearing members in building structures. These sections are used in the construction industry because of their high strength-to-weight ratio, lightweight, quick production, and ease of construction, fabrication, transportation, and handling. When those cold formed sections with high slenderness ratios are subjected to compression bending, they do not reach failure when reaching their ultimate bending stress, however, they sustain much higher loads due stress re-distribution. Hence, there is a need to study the sectional nominal capacity of CFS lipped channel beams with different web openings subjected to pure bending and uniformly distributed loads. By using finite element (FE) simulations using ANSYS APDL for numerical analysis. The results were verified and compared to previous experimental results. Then a parametric study was conducted and validated FE model to investigate the effect of different openings shapes on their nominal capacities. The results have revealed that CFS sections with hexagonal openings and intermediate notch can resist higher nominal capacities when compared to other sectional openings.

Keywords: cold-formed steel, nominal capacity, finite element, lipped channel beam, numerical study, web opening

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Authors: Masoud Mohammadpour, Nima Yazdian, Radovan Kovacevic

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The Oil and Gas industries are vigorously looking for new ways to increase the efficiency of their pipeline constructions. Besides the other approaches, implementing of new welding methods for joining pipes can be the best candidate on this regard. Hybrid Laser Arc Welding (HLAW) with the capabilities of high welding speed, deep penetration, and excellent gap bridging ability can be a possible alternative method in pipeline girth welding. This paper investigates the feasibility of applying the HLAW to join ASTM A106-B as the mostly used piping material for transporting high-temperature and high-pressure fluids and gases. The experiments were carried out on six-inch diameter pipes with the wall thickness of 10mm. AWS ER 70 S6 filler wire with diameter of 1.2mm was employed. Relating to this welding procedure, characterization of welded samples such as hardness, tensile testing and Charpy V-notch testing were performed and the results will be reported in this paper. In order to have better understanding about the thermal history and the microstructural alterations caused by the welding heat cycle, a comprehensive Finite Element (FE) model was also conducted. The obtained results have shown that the Gas Metal Arc Welding (GMAW) procedure with the minimum number of 5 passes to complete the wall thickness, was reduced to only single pass by using the HLAW process with the welding time less than 15s.

Keywords: finite element modeling, high-temperature service, hybrid laser/arc welding, welding pipes

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Authors: Helia Barzegar Sedigh, Farzaneh Hamedi, Payam Ashtari

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There are some limitations in common structural systems, such as providing appropriate lateral stiffness, adequate ductility, and architectural openings at the same time. Consequently, the concept of T-Resisting Frame (TRF) has been introduced to overcome all these deficiencies. The configuration of TRF in this study is a Vertical Plate Girder (VPG) which is placed within the span and two Horizontal Plate Girders (HPGs) connect VPG to side columns at each story level by the use of rigid connections. System performance is improved by utilizing rigid connections in side columns base joint. Shear yield of HPGs causes energy dissipation in TRF; therefore, high plastic deformation in web of HPGs and VPG affects the ductility of system. Moreover, in order to prevent shear buckling in web of TRF’s members and appropriate criteria for placement of web stiffeners are applied. In this paper, an experimental study is conducted by applying cyclic loading and using finite element models and numerical studies such as push over method are assessed on shear and flexural yielding of HPGs. As a result, seismic parameters indicate adequate lateral stiffness, and high ductility factor of 6.73, and HPGs’ shear yielding achieved as a proof of TRF’s better performance.

Keywords: experimental study, finite element model, flexural and shear yielding, t-resisting frame

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Authors: Rui Liu, Pengyu Cui, Nan Jiang

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At present, there is much research on the application of centralized management and cross-integration application of basic geographic information. However, the idea of information integration and sharing between land, sea, and air navigation targets is not deeply applied into the research of navigation information service, especially in the information expression. Targeting at this problem, the paper carries out works about the expression pattern of navigation electronic map for ground vehicles under air and land united navigation mechanism. At first, with the support from multi-source information fusion of GIS vector data, RS data, GPS data, etc., an air and land united information expression pattern is designed aiming at specific navigation task of emergency rescue in the earthquake. And then, the characteristics and specifications of the united expression of air and land navigation information under the constraints of map load are summarized and transferred into expression rules in the rule bank. At last, the related navigation experiment is implemented to evaluate the effect of the expression pattern. The experiment selects evaluation factors of the navigation task accomplishment time and the navigation error rate as the main index, and make comparisons with the traditional single information expression pattern. To sum up, the research improved the theory of navigation electronic map and laid a certain foundation for the design and realization of united navigation system in the aspect of real-time navigation information delivery.

Keywords: navigation electronic map, united navigation, multi-element expression pattern, multi-source information fusion

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Authors: Ranju Chowdhury, Santosh K. Sarkar

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Trace element accumulation potential of ten mangrove species in individual plant tissues (leaves, bark and root/pneumatophore) along with host sediments was carried out at 2 study sites of diverse environmental stresses of Indian Sundarban Wetland, a UNESCO world heritage site. The study was undertaken with the following objectives: (i) to investigate the extent of accumulation and the distribution of trace metals in plant tissues (ii) to determine whether sediment trace metal levels are correlated with trace metal levels in tissues and (iii) to find out the suitable candidate for phytoremediation species. Mangrove sediments showed unique potential in many- fold increase for most trace metals than plant tissues due to their inherent physicochemical properties. The concentrations of studied 11 trace elements (expressed in µg g -1) showed wide range of variations in host sediment with the following descending order: Fe (2865.31-3019.62) > Mn (646.04- 648.47 > Cu (35.03- 41.55) > Zn (32.51- 36.33) > Ni (34.4- 36.60) > Cr (27.5- 29.54) > Pb (11.6- 20.34) > Co (6.79- 8.55) > As (3.22- 4.41) > Cd (0.19- 0.22) > Hg (0.06- 0.07). The ranges of concentration of trace metals (expressed in µg g -1) for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissues were 0.006- 0.31, 0.02- 2.97, 0.10- 4.80, 0.13- 6.49, 4.46- 48.30, 9.20- 938.13, 0.02- 0.13, 9.8- 1726.24, 5.41- 11.34, 0.04 - 7.64, 3.81- 52.20 respectively. Among all trace elements, Cd and Zn were highly bioaccumulated in Excoecaria agallocha (2.97 and 52.20 µg g -1 respectively). The bio- concentration factor (BCF) showed its maximum value (15.5) in E. agallocha for Cd, suggesting that it can be considered as a high-efficient plant for trace metal bioaccumulation. Therefore, phytoremediation could be extensively used for the removal of the toxic contaminants for sustainable management of Sundarban coastal regions.

Keywords: Indian Sundarban, mangroves, phytoremediation, trace elements

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Authors: Derya Gül Ünlü, Oguz Kuş

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The branding of a country means that the country has its own position different from other countries in its region and thus it is perceived more specifically. It is made possible by the branding efforts of a country and the uniqueness of all the national structures, by presenting it in a specific way, by creating the desired image and attracting tourists and foreign investors. Establishing a national brand involves, in a sense, the process of managing the perceptions of the citizens of the other country about the target country, by structuring the image of the country permanently and holistically. By this means, countries are not easily affected by their crisis of international relations. Therefore, within the scope of the research that will be carried out from this point, it is aimed to show how the warplane downing crisis between Turkey and Russia is perceived on social media. The Russian warplane was downed by Turkey on November 24, 2015, on the grounds that Turkey violated the airspace on the Syrian border. Whereupon the relations between the two countries have been tensed, and Russia has called on its citizens not to go to Turkey and citizens in Turkey to return to their countries. Moreover, relations between two countries have been weakened, for example, tourism tours organized in Russia to Turkey and visa-free travel were canceled and all military dialogue was cut off. After the event, various news sites on social media published plenty of news related to topic and the readers made various comments about the event and Turkey. In this context, an investigation into the perception of Turkey's national brand before and after the warplane downing crisis has been conducted. through comments fetched from the reports on the BBC World, and from Al Jazeera English news sites on Facebook accounts, which takes place widely in the social media. In order to realize study, user comments were fetched from jet downing-related news which are published on Facebook fan-page of BBC World Service, and Al Jazeera English. Regarding this, all the news published between 24.10.2015-24.12.2015 and containing Turk and Turkey keyword in its title composed data set of our study. Afterwards, comments written to these news were analyzed via text mining technique. Furthermore, by sentiment analysis, it was intended to reveal reader’s emotions before and after the crisis.

Keywords: Al Jazeera English, BBC World, country branding, social media, text mining

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Authors: Lara Dutil-Fafard, Caroline Rhéaume, Patrick Archambault, Daniel Lafond, Neal W. Pollock

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Improving resources for medical autonomy of astronauts in prolonged space missions, such as a Mars mission, requires not only technology development, but also decision-making support systems. The Advanced Crew Medical System - Medical Condition Requirements study, funded by the Canadian Space Agency, aimed to create knowledge content and a scenario-based query capability to support medical autonomy of astronauts. The key objective of this study was to create a prototype tool for identifying medical infrastructure requirements in terms of medical knowledge, skills and materials. A multicriteria decision-making method was used to prioritize the highest risk medical events anticipated in a long-term space mission. Starting with those medical conditions, event sequence diagrams (ESDs) were created in the form of decision trees where the entry point is the diagnosis and the end points are the predicted outcomes (full recovery, partial recovery, or death/severe incapacitation). The ESD formalism was adapted to characterize and compare possible outcomes of medical conditions as a function of available medical knowledge, skills, and supplies in a given mission scenario. An extensive literature review was performed and summarized in a medical condition database. A PostgreSQL relational database was created to allow query-based evaluation of health outcome metrics with different medical infrastructure scenarios. Critical decision points, skill and medical supply requirements, and probable health outcomes were compared across chosen scenarios. The three medical conditions with the highest risk rank were acute coronary syndrome, sepsis, and stroke. Our efforts demonstrate the utility of this approach and provide insight into the effort required to develop appropriate content for the range of medical conditions that may arise.

Keywords: decision support system, event-sequence diagram, exploration mission, medical autonomy, scenario-based queries, space medicine

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Authors: Behzad Babaei, B. Gangadhara Prusty

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The objective of this study is to assess the hypotheses that a restored tooth with a class II occlusal-distal (OD) cavity can be strengthened by designing an optimized cavity geometry, as well as selecting the composite restoration with optimized elastic moduli when there is a sharp de-bonded edge at the interface of the tooth and restoration. Methods: A scanned human maxillary molar tooth was segmented into dentine and enamel parts. The dentine and enamel profiles were extracted and imported into a finite element (FE) software. The enamel rod orientations were estimated virtually. Fifteen models for the restored tooth with different cavity occlusal depths (1.5, 2, and 2.5 mm) and internal cavity angles were generated. By using a semi-circular stone part, a 400 N load was applied to two contact points of the restored tooth model. The junctions between the enamel, dentine, and restoration were considered perfectly bonded. All parts in the model were considered homogeneous, isotropic, and elastic. The quadrilateral and triangular elements were employed in the models. A mesh convergence analysis was conducted to verify that the element numbers did not influence the simulation results. According to the criteria of a 5% error in the stress, we found that a total element number of over 14,000 elements resulted in the convergence of the stress. A Python script was employed to automatically assign 2-22 GPa moduli (with increments of 4 GPa) for the composite restorations, 18.6 GPa to the dentine, and two different elastic moduli to the enamel (72 GPa in the enamel rods’ direction and 63 GPa in perpendicular one). The linear, homogeneous, and elastic material models were considered for the dentine, enamel, and composite restorations. 108 FEA simulations were successively conducted. Results: The internal cavity angles (α) significantly altered the peak maximum principal stress at the interface of the enamel and restoration. The strongest structures against the contact loads were observed in the models with α = 100° and 105. Even when the enamel rods’ directional mechanical properties were disregarded, interestingly, the models with α = 100° and 105° exhibited the highest resistance against the mechanical loads. Regarding the effect of occlusal cavity depth, the models with 1.5 mm depth showed higher resistance to contact loads than the model with thicker cavities (2.0 and 2.5 mm). Moreover, the composite moduli in the range of 10-18 GPa alleviated the stress levels in the enamel. Significance: For the class II OD cavity models in this study, the optimal geometries, composite properties, and occlusal cavity depths were determined. Designing the cavities with α ≥100 ̊ was significantly effective in minimizing peak stress levels. The composite restoration with optimized properties reduced the stress concentrations on critical points of the models. Additionally, when more enamel was preserved, the sturdier enamel-restoration interface against the mechanical loads was observed.

Keywords: dental composite restoration, cavity geometry, finite element approach, maximum principal stress

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Authors: Mohamed Djalil Zaafour, Samir Chekchaki, Mohamed Benslama

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The Landfill of El Matrouha is located in El-Tarf town (extreme north east of Algeria), the Landfill is present as a gigantic wild dump. This waste dump occupies an area of over four hectares, tons of rubbish that is sent daily are scattered over kilometers, reaching farmland located west of the town, the landfill is close to a temporary Oued, which supply Oued Guergour the last tributary Oued El Kebir. The landfills are causing serious environmental damage, following the infiltration of leachates, which contribute to the degradation of water quality, in the context of this problem, the purpose of the work is focused on assessing the impact of this landfill on Oued El-Kebir, for this a series of sampling and analysis of the soil and water of this Oued was performed; The results show that the soil collected reveal the sandy texture facilitating infiltration and percolation of leachate from the landfill; the physicochemical analysis of the quality of the river water reveals high levels of sulfates in fact this element is one of the essential constituents of the mineral fraction of the waste presenting a risk of pollution by this element, The recorded values for nutrients are sub-standard, for trace elements analysis shows very low metal load on the river except for lead, which is present at high concentrations exceeding all standard.

Keywords: Algeria, landfill, leachates, Oued El-kebir

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Authors: Jui-Pui Hung, Yu-Sheng Lai, Tzuo-Liang Luo, Kung-Da Wu, Yun-Ji Zhan

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This study presented the investigation of the influence of the tool holder interface stiffness on the dynamic characteristics of a spindle tool system. The interface stiffness was produced by drawbar force on the tool holder, which tends to affect the spindle dynamics. In order to assess the influence of interface stiffness on the vibration characteristic of spindle unit, we first created a three dimensional finite element model of a high speed spindle system integrated with tool holder. The key point for the creation of FEM model is the modeling of the rolling interface within the angular contact bearings and the tool holder interface. The former can be simulated by a introducing a series of spring elements between inner and outer rings. The contact stiffness was calculated according to Hertz contact theory and the preload applied on the bearings. The interface stiffness of the tool holder was identified through the experimental measurement and finite element modal analysis. Current results show that the dynamic stiffness was greatly influenced by the tool holder system. In addition, variations of modal damping, static stiffness and dynamic stiffness of the spindle tool system were greatly determined by the interface stiffness of the tool holder which was in turn dependent on the draw bar force applied on the tool holder. Overall, this study demonstrates that identification of the interface characteristics of spindle tool holder is of very importance for the refinement of the spindle tooling system to achieve the optimum machining performance.

Keywords: dynamic stiffness, spindle-tool holder, interface stiffness, drawbar force

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Authors: Junwon Seo, Bipin Adhikari, Euiseok Jeong

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This paper is intended to evaluate the structural performance of welded electronic road signs under various damage scenarios (DSs) using a finite element (FE) model calibrated with full-scale ultimate load testing results. The tested electronic road sign specimen was built with a back skin made of 5052 aluminum and two channels and a frame made of 6061 aluminum, where the back skin was connected to the frame by welding. The size of the tested specimen was 1.52 m long, 1.43 m wide, and 0.28 m deep. An actuator applied vertical loads at the center of the back skin of the specimen, resulting in a displacement of 158.7 mm and an ultimate load of 153.46 kN. Using these testing data, generation and calibration of a FE model of the tested specimen were executed in ABAQUS, indicating that the difference in the ultimate load between the calibrated model simulation and full-scale testing was only 3.32%. Then, six different DSs were simulated where the areas of the welded connection in the calibrated model were diminished for the DSs. It was found that the corners at the back skin-frame joint were prone to connection failure for all the DSs, and failure of the back skin-frame connection occurred remarkably from the distant edges.

Keywords: computational analysis, damage scenarios, electronic road signs, finite element, welded connections

Procedia PDF Downloads 92

Authors: Runliang Wang, Jianhua Liu, Duo Jia, Xiaoyu Ding

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The contact between sealing surfaces plays a vital role in guaranteeing the sealing performance of various seals. To date, analyses of sealing structures have rarely considered both structural parameters (macroscale) and surface roughness information (microscale) of sealing surfaces due to the complex modeling process. Meanwhile, most of the contact analyses applied to seals were conducted only under normal loading, which still existssome distance from real loading conditions in engineering. In this paper, a multiscale rough contact model, which took both macrostructural parameters of seals and surface roughness information of sealing surfaces into consideration for the cone-cone seal, was established. By using the finite element method (FEM), the combined normal and tangential loading was applied to the model to simulate the assembly process of the cone-cone seal. The evolution of the contact behaviors during the assembly process, such as the real contact area (RCA), the distribution of contact pressure, and contact status, are studied in detail. The results showed the non-linear relationship between the RCA and the load, which was different from the normal loading cases. In addition, the evolution of the real contact area of cone-cone seals with isotropic and anisotropic rough surfaces are also compared quantitatively.

Keywords: contact mechanics, FEM, randomly rough surface, real contact area, sealing

Procedia PDF Downloads 183

Authors: Ahmed Hammad, Yehia Abdel-Nasser, Mohamed Shamma

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The main configuration of ship construction consists of standard and fabricated stiffening members which are commonly used in shipbuilding such as fabricated T-sections. During the welding process, the non-uniform heating and rapid cooling lead to the inevitable presence of out-of-plane distortion and welding induced residual stresses. Because of these imperfections, the fabricated structural members may not attain their design load to be carried. The removal of these imperfections will require extra man-hours. In the present work, controlling these imperfections has been investigated at both design and fabrication stages. A typical fabricated T-girder is selected to investigate the problem of these imperfections using double-side welding. A numerical simulation based on finite element (FE) modeling has been used to investigate the effect of different parameters of the selected fabricated T-girder such as geometrical properties and welding sequences on the magnitude of welding imperfections. FE results were compared with the results of experimental model of a double-side fillet weld. The present work concludes that: Firstly, in the design stage, the optimum geometry of the fabricated T- girder is determined based on minimum steel weight and out- of- plane distortion. Secondly, in the fabrication stage, the best welding sequence is determined on the basis of minimum welding out- of- plane distortion.

Keywords: fabricated T-girder, FEM, out-of-plane distortion, section modulus, welding residual stresses

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Authors: M. Vieira, V. Infante, P. Serrão, A. Ribeiro

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The Portuguese guitar is a pear-shaped plucked chordophone particularly known for its role in Fado, the most distinctive traditional Portuguese musical style. The acknowledgment of the dynamic behavior of the Portuguese guitar, specifically of its modal and mode shape response, has been the focus of different authors. In this research, the experimental results of the dynamic behavior of the guitar, which were previously obtained, are correlated with a vibro-acoustic finite element model of the guitar. The modelling of the guitar offered several challenges which are presented in this work. The results of the correlation between experimental and numerical data are presented and indicate good correspondence for the studied mode shapes. The influence of the air inside the chamber, for the finite element analysis, is shown to be crucial to understand the low-frequency modes of the Portuguese guitar, while, for higher frequency modes, the geometry of the guitar assumes greater relevance. Comparison is made with the classical guitar, providing relevant information about the intrinsic differences between the two, such as between its tones and other acoustical properties. These results represent a sustained base for future work, which will allow the study of the influence of different location and geometry of diverse components of the Portuguese guitar, being as well an asset to the comprehension of its musical properties and qualities and may, furthermore, represent an advantage for its players and luthiers.

Keywords: dynamic behavior of guitars, instrument acoustics, modal analysis, Portuguese guitar

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Authors: Mohamed A. Shanan, Ashraf H. El-Zanaty, Kamal G. Metwally

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This paper presents the effect of concrete compressive strength and rectangularity ratio on strength and ductility of normal and high strength reinforced concrete columns confined with transverse steel under axial compressive loading. Nineteen normal strength concrete rectangular columns with different variables tested in this research were used to study the effect of concrete compressive strength and rectangularity ratio on strength and ductility of columns. The paper also presents a nonlinear finite element analysis for these specimens and another twenty high strength concrete square columns tested by other researchers using ANSYS 15 finite element software. The results indicate that the axial force – axial strain relationship obtained from the analytical model using ANSYS are in good agreement with the experimental data. The comparison shows that the ANSYS is capable of modeling and predicting the actual nonlinear behavior of confined normal and high-strength concrete columns under concentric loading. The maximum applied load and the maximum strain have also been confirmed to be satisfactory. Depending on this agreement between the experimental and analytical results, a parametric numerical study was conducted by ANSYS 15 to clarify and evaluate the effect of each variable on strength and ductility of the columns.

Keywords: ANSYS, concrete compressive strength effect, ductility, rectangularity ratio, strength

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Authors: Fadi Al-Badour, Nesar Merah, Abdelrahman Shuaib, Abdelaziz Bazoune

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In the current work, a Coupled Eulerian Lagrangian (CEL) model is developed to simulate the friction stir welding (FSW) process of dissimilar Aluminum alloys (Al 6061-T6 with Al 5083-O). The model predicts volumetric defects, material flow, developed temperatures, and stresses in addition to tool reaction loads. Simulation of welding phase is performed by employing a control volume approach, whereas the welding speed is defined as inflow and outflow over Eulerian domain boundaries. Only material softening due to inelastic heat generation is considered and material behavior is assumed to obey Johnson-Cook’s Model. The model was validated using published experimentally measured temperatures, at similar welding conditions, and by qualitative comparison of dissimilar weld microstructure. The FE results showed that most of developed temperatures were below melting and that the bulk of the deformed material in solid state. The temperature gradient on AL6061-T6 side was found to be less than that of Al 5083-O. Changing the position Al 6061-T6 from retreating (Ret.) side to advancing (Adv.) side led to a decrease in maximum process temperature and strain rate. This could be due to the higher resistance of Al 6061-T6 to flow as compared to Al 5083-O.

Keywords: friction stir welding, dissimilar metals, finite element modeling, coupled Eulerian Lagrangian Analysis

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Authors: Sophie Del Fa, Loup Ducol

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This presentation will focus on the discursive practices of Les Soulèvements de la Terre (hereafter SdlT), a French environmentalist group mobilized against agribusiness. More specifically, we will use, as a case study, the violently repressed demonstration that took place in Sainte-Soline on March 25, 2023 (see after for details). The SdlT embodies the renewal of anti-capitalist and environmentalist struggles that began with Occupy Wall Street in 2009 and in France with the Nuit debout in 2016 and the yellow vests movement from 2019 to 2020. These struggles have three things in common: they are self-organized without official leaders, they rely mainly on occupations to reappropriate public places (squares, roundabouts, natural territories) and they are anti-capitalist. The SdlT was created in 2021 by activists coming from the Zone-to-Defend of Notre-Dame-des-Landes, a victorious 10 yearlong occupation movement against an airport near Nantes, France (from 2009 to 2018). The SdlT is not labeled as a formal association, nor as a constituted group, but as an anti-capitalist network of local struggles at the crossroads of ecology and social issues. Indeed, although they target agro-industry, land grabbing, soil artificialization and ecology without transition, the SdlT considers ecological and social questions as interdependent. Moreover, they have an encompassing vision of ecology that they consider as a concern for the living as a whole by erasing the division between Nature and Culture. Their radicality is structured around three main elements: federative and decentralized dimensions, the rhetoric of living alliances and militant creatives strategies. The objective of this reflexion is to understand how these three dimensions are articulated through the SdlT’s discursive practices. To explore these elements, we take as a case study one specific event: the demonstration against the ‘basins’ held in Sainte-Soline on March 25, 2023, on the construction site of new water storage infrastructure for agricultural irrigation in western France. This event represents a turning point for the SdlT. Indeed, the protest was violently repressed: 5000 grenades were fired by the police, hundreds of people were injured, and one person was still in a coma at the time of writing these lines. Moreover, following Saint-Soline’s events, the Minister of Interior Affairs, Gérald Darmin, threatened to dissolve the SdlT, thus adding fuel to the fire in an already tense social climate (with the ongoing strikes against the pensions reform). We anchor our reflexion on three types of data: 1) our own experiences (inspired by ethnography) of the Sainte-Soline demonstration; 2) the collection of more than 500 000 Tweets with the #SainteSoline hashtag and 3) a press review of texts and articles published after Sainte-Soline’s demonstration. The exploration of these data from a turning point in the history of the SdlT will allow us to analyze how the three dimensions highlighted earlier (federative and decentralized dimensions, rhetoric of living alliances and creatives militant strategies) are materialized through the discursive practices surrounding the Sainte-Soline event. This will allow us to shed light on how a new contemporary movement implements contemporary environmental struggles.

Keywords: discursive practices, Sainte-Soline, Ecology, radical ecology

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Authors: Raoudane Bouziyan, Kawser Mohammad Tawhid

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Microstrip antennas are low in profile, light in weight, conformable in structure and are now developed for many applications. The main difficulty of the microstrip antenna is its narrow bandwidth. Several modern applications like satellite communications, remote sensing, and multi-function radar systems will find it useful if there is dual-band antenna operating from a single aperture. Some applications require covering both transmitting and receiving frequency bands which are spaced apart. Providing multiple antennas to handle multiple frequencies and polarizations becomes especially difficult if the available space is limited as with airborne platforms and submarine periscopes. Dual band operation can be realized from a single feed using slot loaded or stacked microstrip antenna or two separately fed antennas sharing a common aperture. The former design, when used in arrays, has certain limitations like complicated beam forming or diplexing network and difficulty to realize good radiation patterns at both the bands. The second technique provides more flexibility with separate feed system as beams in each frequency band can be controlled independently. Another desirable feature of a dual band antenna is easy adjustability of upper and lower frequency bands. This thesis presents investigation of a new dual-band antenna, which is a hybrid of microstrip and waveguide radiating elements. The low band radiator is a Shorted Annular Ring (SAR) microstrip antenna and the high band radiator is an aperture antenna. The hybrid antenna is realized by forming a waveguide radiator in the shorted region of the SAR microstrip antenna. It is shown that the upper to lower frequency ratio can be controlled by the proper choice of various dimensions and dielectric material. Operation in both linear and circular polarization is possible in either band. Moreover, both broadside and conical beams can be generated in either band from this antenna element. Finite Element Method based software, HFSS and Method of Moments based software, FEKO were employed to perform parametric studies of the proposed dual-band antenna. The antenna was not tested physically. Therefore, in most cases, both HFSS and FEKO were employed to corroborate the simulation results.

Keywords: FEKO, HFSS, dual band, shorted annular ring patch

Procedia PDF Downloads 402

Authors: Mustapha Kamel Mihoubi, Essadik Kerkar, Abdelhamid Hebbouche

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According to the randomness of most of the factors affecting the stability of a gravity dam, probability theory is generally used to TESTING the risk of failure and there is a confusing logical transition from the state of stability failed state, so the stability failure process is considered as a probable event. The control of risk of product failures is of capital importance for the control from a cross analysis of the gravity of the consequences and effects of the probability of occurrence of identified major accidents and can incur a significant risk to the concrete dam structures. Probabilistic risk analysis models are used to provide a better understanding the reliability and structural failure of the works, including when calculating stability of large structures to a major risk in the event of an accident or breakdown. This work is interested in the study of the probability of failure of concrete dams through the application of the reliability analysis methods including the methods used in engineering. It is in our case of the use of level II methods via the study limit state. Hence, the probability of product failures is estimated by analytical methods of the type FORM (First Order Reliability Method), SORM (Second Order Reliability Method). By way of comparison, a second level III method was used which generates a full analysis of the problem and involving an integration of the probability density function of, random variables are extended to the field of security by using of the method of Mont-Carlo simulations. Taking into account the change in stress following load combinations: normal, exceptional and extreme the acting on the dam, calculation results obtained have provided acceptable failure probability values which largely corroborate the theory, in fact, the probability of failure tends to increase with increasing load intensities thus causing a significant decrease in strength, especially in the presence of combinations of unique and extreme loads. Shear forces then induce a shift threatens the reliability of the structure by intolerable values of the probability of product failures. Especially, in case THE increase of uplift in a hypothetical default of the drainage system.

Keywords: dam, failure, limit state, monte-carlo, reliability, probability, sliding, Taylor

Procedia PDF Downloads 318

Authors: Ayşe Duygu Kaçar

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Industrial regions and buildings that have stopped their primary functions are in the interest of the discipline of architecture in the last decades. The renewal of these spaces of production for different functions is a common aspect for contemporary world countries. Totally different functions can be added to the existing as well, which can help improving the social, cultural and aesthetic character of these beings and sustaining their uniqueness. Therefore, these sites linking the past and future can be used as museums, exhibition centers, art ateliers, city parks, recreational centers, botanic gardens, sculpture parks, theatres, etc. in order to continue their place in the collective memory of the cities. The present paper depicts a way of shedding light on the Cotton Textile Industry (İplik ve Dokuma Fabrikası A.Ş), a local industrial site in Antalya, the most popular tourism center of Turkey, as a part of International Architecture Biennale, 2011 and on Lohberg coal mine, a local industrial site in the Ruhr region of Germany. As a transparent, fragile, temporary and economical material, the string was used as a design element in both experiential architecture works with architecture students and the outcomes will be discussed and presented through the theme 'rejecting / reversing architecture'.

Keywords: industrial sites, the Cotton Textile Industry Antalya, Lohberg coal mine, architectural design, identity

Procedia PDF Downloads 309

Authors: Grzegorz Kubinski

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In the proposed paper, we would like to present the phenomenon of disease and disability as an element of discourse redefining the contemporary canons of beauty and the category of normativity. In widely understood media, and above all in social media and fashion industry, the use of the disease as an aesthetic category has long been observed. There is an interesting case of promoting and maintaining a certain, ideal pattern of physical beauty, while at the same time very clear exploitation of various types of illnesses. The categories of disease and disabled body are shown as an element of the expression of the individuality and originality of one's own identity, while at the same time the disabled person is still experiencing social exclusion. Illness or body abnormality as an aesthetic category also functions as an ethical-political category. The analysis of the interrelations of these discourses will be presented on the example of selected projects present in social media, like Instagram or Facebook. We would like to present how old forms of 'curiosities' or 'abnormalities' turned into mainstream forms of a new aesthetic. For marginalized disabled people, there is a new form of expression and built their identity. But, there is an interesting point: are this contemporary forms of using disability and illness really new? Or maybe this is just another form of Wunderkammer or even cabinets of curiosities? We propose to analyze contemporary cultural and social context in order to clarify this issue. On the other hand, we would like to present some examples from personal interviews with disabled internet influencers and statements disabled persons concerning the role of the different body in society (e.g. #bodypositive, #perfeclyflawed).

Keywords: disability, new media, defect, fashion

Procedia PDF Downloads 188

Authors: Hasan Husnu Korkmaz, Serra Zerrin Korkmaz

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The reinforced concrete (RC) framed structures composed of beams, columns, shear walls and the slabs. The other members are assumed to be nonstructural. Especially the brick infill walls which are used to separate the rooms or spaces are just handled as dead loads. On the other hand, if these infills are constructed within the frame bays, they also have higher shear and compression capacities. It is a well-known fact that, brick infills increase the lateral rigidity of the structure and thought to be a reserve capacity in the design. But, brick infills can create unfavorable failure or damage modes in the earthquake action such as soft story or short columns. The increase in the lateral rigidity also causes an over estimation of natural period of the structure and the corresponding earthquake loads in the design are less than the actual ones. In order to obtain accurate and realistic design results, the infills must be modelled in the structural design and their capacities must be included. Unfortunately, in Turkish Earthquake Code, there is no design methodology for the engineers. In this paper, finite element modelling of infilled reinforced concrete structures are studied. The proposed or used method is compared with the experimental results of a previous study. The effect of infills on the structural response is expressed within the paper.

Keywords: seismic loading, brick infills, finite element analysis, reinforced concrete, earthquake code

Procedia PDF Downloads 314

Authors: Sruthi Raveendran

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Developmental dyslexia, characterized by reading difficulties despite normal intelligence, presents a significant challenge for bilingual children navigating languages with varying degrees of orthographic transparency. This study bridges a critical gap in dyslexia interventions for bilingual populations in India by examining how consistency and predictability of letter-sound relationships in a writing system (orthographic transparency) influence the ability to understand and manipulate the building blocks of sound in language (phonological processing). The study employed a computerized visual rhyme-judgment task with concurrent EEG (electroencephalogram) recording. The task compared reaction times, accuracy of performance, and event-related potential (ERP) components (N170, N400, and LPC) for rhyming and non-rhyming stimuli in two orthographies: English (opaque orthography) and Kannada (transparent orthography). As hypothesized, the results revealed advantages in phonological processing tasks for transparent orthography (Kannada). Children with dyslexia were faster and more accurate when judging rhymes in Kannada compared to English. This suggests that a language with consistent letter-sound relationships (transparent orthography) facilitates processing, especially for tasks that involve manipulating sounds within words (rhyming). Furthermore, brain activity measured by event-related potentials (ERP) showed less effort required for processing words in Kannada, as reflected by smaller N170, N400, and LPC amplitudes. These findings highlight the crucial role of orthographic transparency in optimizing reading performance for bilingual children with dyslexia. These findings emphasize the need for language-specific intervention strategies that consider the unique linguistic characteristics of each language. While acknowledging the complexity of factors influencing dyslexia, this research contributes valuable insights into the impact of orthographic transparency on phonological awareness in bilingual children. This knowledge paves the way for developing tailored interventions that promote linguistic inclusivity and optimize literacy outcomes for children with dyslexia.

Keywords: developmental dyslexia, phonological awareness, rhyme judgment, orthographic transparency, Kannada, English, N170, N400, LPC

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Authors: H. Selcuk Halkacı, Mevlüt Türköz, Ekrem Öztürk, Murat Dilmec

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Various attempts concerning the low formability issue for lightweight materials like aluminium and magnesium alloys are being investigated in many studies. Advanced forming processes such as hydroforming is one of these attempts. In last decades sheet hydroforming process has an increasing interest, particularly in the automotive and aerospace industries. This process has many advantages such as enhanced formability, the capability to form complex parts, higher dimensional accuracy and surface quality, reduction of tool costs and reduced die wear compared to the conventional sheet metal forming processes. There are two types of sheet hydroforming. One of them is hydromechanical deep drawing (HDD) that is a special drawing process in which pressurized fluid medium is used instead of one of the die half compared to the conventional deep drawing (CDD) process. Another one is sheet hydroforming with die (SHF-D) in which blank is formed with the act of fluid pressure and it takes the shape of die half. In this study, transition of cup height according to cup diameter between the processes was determined by performing simulation of the processes in Finite Element Analysis. Firstly SHF-D process was simulated for 40 mm cup diameter at different cup heights chancing from 10 mm to 30 mm and the cup height to diameter ratio value in which it is not possible to obtain a successful forming was determined. Then the same ratio was checked for a different cup diameter of 60 mm. Then thickness distributions of the cups formed by SHF-D and HDD processes were compared for the cup heights. Consequently, it was found that the thickness distribution in HDD process in the analyses was more uniform.

Keywords: finite element analysis, HDD, hydroforming sheet metal forming, SHF-D

Procedia PDF Downloads 429

Authors: Louis N. Y. Wong

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En-echelon fractures are commonly found in rocks, which appear as a special set of regularly oriented and spaced fractures. By using both experimental and numerical approaches, this study investigates the interaction among them, and how this interaction finally contributes to the development of a shear rupture (fault), especially in brittle natural rocks. Firstly, uniaxial compression tests are conducted on marble specimens containing en-echelon flaws. The latter is cut by using the water abrasive jet into the rock specimens. The fracturing processes of these specimens leading to the formation of a fault are observed in detail by the use of a high speed camera. The influences of the flaw geometry on the production of tensile cracks and shear cracks, which in turn dictate the coalescence patterns of the entire set of en-echelon flaws are comprehensively studied. Secondly, a numerical study based on a recently developed contact model, flat-joint contact model using the discrete element method (DEM) is carried out to model the present laboratory experiments. The numerical results provide a quantitative assessment of the interaction of en-echelon flaws. Particularly, the evolution of the stress field, as well as the characteristics of new crack initiation, propagation and coalescence associated with the generation of an eventual shear rupture are studied in detail. The numerical results are found to agree well with the experimental results obtained in both microscopic and macroscopic observations.

Keywords: discrete element method, en-echelon flaws, fault, marble

Procedia PDF Downloads 255