Search results for: magnetic circuit material

Authors: Sumit Kumar Vishawakarma, Tapas Ranjan Panihari

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The article investigates the propagation behavior of SV-wave, SH-wave, and P-wave in a continuously inhomogeneous cross-anisotropic material, where the material properties such as Young's moduli, shear modulus, and density vary as an arbitrary continuous function of depth. In the considered model, Hook's law, strain-displacement relations along with equilibrium equations have been used to derive the governing equation. The mathematical formulation of this physical problem gives rise to an eigenvalue problem with displacement components as fundamental variables. This leads to achieving the closed-form expressions for quasi-wave velocities of SV-wave, SH-wave, and P-wave in the considered framework. These characteristics of wave propagation along with the above-stated variation have been scrutinized based on their numerical results. This parametric study reveals that wave velocity remarkably fluctuates as the magnitude of inhomogeneity parameters increases and decreases. The prominent effect has been shown depicting the dependence of wave velocity on the degree of material anisotropy. The influence of phase angle and depth of the medium has been remarkably established. The present study may facilitate the theoretical foundation and practical application in the field of earthquake source mechanisms.

Keywords: cross-anisotropic, inhomogeneity, P-wave, SH-wave, SV-wave, shear modulus, Young’s modulus

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Authors: Edwin Calderon-Mendoza, Patrick Schweitzer, Serge Weber

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Series arc faults appear frequently and unpredictably in low voltage distribution systems. Many methods have been developed to detect this type of faults and commercial protection systems such AFCI (arc fault circuit interrupter) have been used successfully in electrical networks to prevent damage and catastrophic incidents like fires. However, these devices do not allow series arc faults to be located on the line in operating mode. This paper presents a location algorithm for series arc fault in a low-voltage indoor power line in an AC 230 V-50Hz home network. The method is validated through simulations using the MATLAB software. The fault location method uses electrical parameters (resistance, inductance, capacitance, and conductance) of a 49 m indoor power line. The mathematical model of a series arc fault is based on the analysis of the V-I characteristics of the arc and consists basically of two antiparallel diodes and DC voltage sources. In a first step, the arc fault model is inserted at some different positions across the line which is modeled using lumped parameters. At both ends of the line, currents and voltages are recorded for each arc fault generation at different distances. In the second step, a fault map trace is created by using signature coefficients obtained from Kirchhoff equations which allow a virtual decoupling of the line’s mutual capacitance. Each signature coefficient obtained from the subtraction of estimated currents is calculated taking into account the Discrete Fast Fourier Transform of currents and voltages and also the fault distance value. These parameters are then substituted into Kirchhoff equations. In a third step, the same procedure described previously to calculate signature coefficients is employed but this time by considering hypothetical fault distances where the fault can appear. In this step the fault distance is unknown. The iterative calculus from Kirchhoff equations considering stepped variations of the fault distance entails the obtaining of a curve with a linear trend. Finally, the fault distance location is estimated at the intersection of two curves obtained in steps 2 and 3. The series arc fault model is validated by comparing current registered from simulation with real recorded currents. The model of the complete circuit is obtained for a 49m line with a resistive load. Also, 11 different arc fault positions are considered for the map trace generation. By carrying out the complete simulation, the performance of the method and the perspectives of the work will be presented.

Keywords: indoor power line, fault location, fault map trace, series arc fault

Procedia PDF Downloads 137

Authors: Lingju Wu, Hao Hua

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This paper presents a digital fashion production methodology and workflow based on fused deposition modeling additive manufacturing technology, as demonstrated through a 3D printed fashion show held at Southeast University in Nanjing, China. Unlike traditional fashion, 3D printed fashion allows for the creation of complex geometric shapes and unique structural designs, facilitating diverse reconfiguration and sustainable production of textile fabrics. The proposed methodology includes two components: morphogenesis and the 3D printing process. The morphogenesis part comprises digital design methods such as mesh deformation, structural reorganization, particle flow stretching, sheet partitioning, and spreading methods. The 3D printing process section includes three types of methods: sculptural objects, multi-material composite fabric, and self-forming composite fabrics. This paper focuses on multi-material composite fabrics and self-forming composite fabrics, both of which involve weaving fabrics with 3D-printed material sandwiches. Multi-material composite fabrics create specially tailored fabric from the original properties of the printing path and multiple materials, while self-forming fabrics apply pre-stress to the flat fabric and then print the sandwich, allowing the fabric's own elasticity to interact with the printed components and shape into a 3D state. The digital design method and workflow enable the integration of abstract sensual aesthetics and rational thinking, showcasing a digital aesthetic that challenges conventional handicraft workshops. Overall, this paper provides a comprehensive framework for the production of 3D-printed fashion, from concept to final product.

Keywords: digital fashion, composite fabric, self-forming structure, additive manufacturing, generating design

Procedia PDF Downloads 123

Authors: Erva Akin

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– The use of copyrighted material for machine learning purposes is a challenging issue in the field of artificial intelligence (AI). While machine learning algorithms require large amounts of data to train and improve their accuracy and creativity, the use of copyrighted material without permission from the authors may infringe on their intellectual property rights. In order to overcome copyright legal hurdle against the data sharing, access and re-use of data, the use of copyrighted material for machine learning purposes may be considered permissible under certain circumstances. For example, if the copyright holder has given permission to use the data through a licensing agreement, then the use for machine learning purposes may be lawful. It is also argued that copying for non-expressive purposes that do not involve conveying expressive elements to the public, such as automated data extraction, should not be seen as infringing. The focus of such ‘copy-reliant technologies’ is on understanding language rules, styles, and syntax and no creative ideas are being used. However, the non-expressive use defense is within the framework of the fair use doctrine, which allows the use of copyrighted material for research or educational purposes. The questions arise because the fair use doctrine is not available in EU law, instead, the InfoSoc Directive provides for a rigid system of exclusive rights with a list of exceptions and limitations. One could only argue that non-expressive uses of copyrighted material for machine learning purposes do not constitute a ‘reproduction’ in the first place. Nevertheless, the use of machine learning with copyrighted material is difficult because EU copyright law applies to the mere use of the works. Two solutions can be proposed to address the problem of copyright clearance for AI training data. The first is to introduce a broad exception for text and data mining, either mandatorily or for commercial and scientific purposes, or to permit the reproduction of works for non-expressive purposes. The second is that copyright laws should permit the reproduction of works for non-expressive purposes, which opens the door to discussions regarding the transposition of the fair use principle from the US into EU law. Both solutions aim to provide more space for AI developers to operate and encourage greater freedom, which could lead to more rapid innovation in the field. The Data Governance Act presents a significant opportunity to advance these debates. Finally, issues concerning the balance of general public interests and legitimate private interests in machine learning training data must be addressed. In my opinion, it is crucial that robot-creation output should fall into the public domain. Machines depend on human creativity, innovation, and expression. To encourage technological advancement and innovation, freedom of expression and business operation must be prioritised.

Keywords: artificial intelligence, copyright, data governance, machine learning

Procedia PDF Downloads 83

Authors: Florian Tille, Heide Weishaar, Bernhard Gibis, Susanne Schnitzer

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Introduction: The quality of patient-doctor communication and of written health information is central to organizational health literacy (HL). Whether patients understand their doctors’ explanations and textual material on health, however, is understudied. This study identifies the overall levels of patient understanding of health information and its associations with patients’ social characteristics in outpatient health care in Germany. Materials & Methods: This analysis draws on data collected via a 2017 national health survey with a sample of 6,105 adults. Quality of communication was measured for consultations with general practitioners (GPs) and specialists (SPs) via the Ask Me 3 program questions, and through a question on written health material. Correlations with social characteristics were explored employing bivariate and multivariate logistic regression analyses. Results: Over 90% of all respondents reported that they had understood their doctors’ explanations during the last consultation. Failed understanding was strongly correlated with patients’ very poor health (Odds Ratio [OR]: 5.19; 95% confidence interval [CI]: 2.23–12.10; ref. excellent/very good health), current health problem (OR: 6.54, CI: 1.70–25.12; ref. preventive examination) and age 65 years and above (OR: 2.97, CI: 1.10–8.00; ref. 18 to 34 years). Fewer patients answered they understood written material well (86.7% for las visit at GP, 89.7% at SP). Understanding written material poorly was highly associated with basic education (OR: 4.20, CI: 2.76–6.39; ref. higher education) and 65 years old and above (OR: 2.66, CI: 1.43–4.96). Discussion: Overall ratings of oral patient-doctor communication and written communication of health information are high. Yet, a considerable share of patients reports not-understanding their doctors and poor understanding of the written health-related material. Interventions that can contribute to improving organizational HL in outpatient care in Germany include HL training for doctors, reducing system barriers to easily-accessible health information for patients and combining oral and written health communication means. Conclusion: This work adds to the study of organizational HL in Germany. To increase patient understanding of health-relevant information and thereby possibly reduce health disparities, meeting the communication needs especially of persons in different age groups, with basic education and in very poor health is suggested.

Keywords: health survey, organizational health literacy, patient-doctor communication, social characteristics, outpatient care, Ask Me 3

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Authors: F. Rarbi, D. Dzahini, W. Uhring

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In this paper, a dynamic and power efficient 8-bit and 100-MSPS Successive Approximation Register (SAR) Analog-to-Digital Converter (ADC) is presented. The circuit uses a non-differential capacitive Digital-to-Analog (DAC) architecture segmented by 2. The prototype is produced in a commercial 65-nm 1P7M CMOS technology with 1.2-V supply voltage. The size of the core ADC is 208.6 x 103.6 µm². The post-layout noise simulation results feature a SNR of 46.9 dB at Nyquist frequency, which means an effective number of bit (ENOB) of 7.5-b. The total power consumption of this SAR ADC is only 1.55 mW at 100-MSPS. It achieves then a figure of merit of 85.6 fJ/step.

Keywords: CMOS analog to digital converter, dynamic comparator, image sensor application, successive approximation register

Procedia PDF Downloads 418

Authors: A. Benhamena, L. Aminallah, A. Aid, M. Benguediab, A. Amrouche

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The goal of this work is to analyze the severity of interfacial stress distribution in the single lap adhesive joint under tensile loading. The three-dimensional and non-linear finite element method based on the computation of the peel and shear stresses was used to analyze the fracture behaviour of single lap adhesive joint. The effect of the loading magnitude and the overlap length on the distribution of peel and shear stresses was highlighted. A good correlation was found between the FEM simulations and the analytical results.

Keywords: aluminum 2024-T3 alloy, single-lap adhesive joints, Interface stress distributions, material nonlinear analysis, adhesive, bending moment, finite element method

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Authors: Mostefa Bendouba, Djebli Abdelkader, Abdelkrim Aid, Mohamed Benguediab

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The damage evolution mechanism is one of the important focuses of fatigue behaviour investigation of composite materials and also is the foundation to predict fatigue life of composite structures for engineering application. This paper is dedicated to a damage investigation under two block loading cycle fatigue conditions submitted to composite material. The loading sequence effect and the influence of the cycle ratio of the first stage on the cumulative fatigue life were studied herein. Two loading sequences, i.e., high-to-low and low-to-high cases are considered in this paper. The proposed damage indicator is connected cycle by cycle to the S-N curve and the experimental results are in agreement with model expectations. Some experimental researches are used to validate this proposition.

Keywords: fatigue, damage acumulation, composite, evolution

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Authors: Meng Miao, Jeongwoo Han, Cam Nguyen

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Ultra-wideband (UWB) time-domain impulse communication and radar systems use ultra-short duration pulses in the sub-nanosecond regime, instead of continuous sinusoidal waves, to transmit information. The pulse directly generates a very wide-band instantaneous signal with various duty cycles depending on specific usages. In UWB systems, the total transmitted power is spread over an extremely wide range of frequencies; the power spectral density is extremely low. This effectively results in extremely small interference to other radio signals while maintains excellent immunity to interference from these signals. UWB devices can therefore work within frequencies already allocated for other radio services, thus helping to maximize this dwindling resource. Therefore, impulse UWB technique is attractive for realizing high-data-rate, short-range communications, ground penetrating radar (GPR), and military radar with relatively low emission power levels. UWB antennas are the key element dictating the transmitted and received pulse shape and amplitude in both time and frequency domain. They should have good impulse response with minimal distortion. To facilitate integration with transmitters and receivers employing microwave integrated circuits, UWB antennas enabling direct integration are preferred. We present the development of two UWB antennas operating from 3.1 to 10.6 GHz and 0.3-6 GHz for UWB systems that provide direct integration with microwave integrated circuits. The operation of these antennas is based on the principle of wave propagation on a non-uniform transmission line. Time-domain EM simulation is conducted to optimize the antenna structures to minimize reflections occurring at the open-end transition. Calculated and measured results of these UWB antennas are presented in both frequency and time domains. The antennas have good time-domain responses. They can transmit and receive pulses effectively with minimum distortion, little ringing, and small reflection, clearly demonstrating the signal fidelity of the antennas in reproducing the waveform of UWB signals which is critical for UWB sensors and communication systems. Good performance together with seamless microwave integrated-circuit integration makes these antennas good candidates not only for UWB applications but also for integration with printed-circuit UWB transmitters and receivers.

Keywords: antennas, ultra-wideband, UWB, UWB communication systems, UWB radar systems

Procedia PDF Downloads 238

Authors: Bachir Kacimi, Fatiha Teklal, Arezki Djebbar

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Forming processes induce residual deformations on the reinforcement and sometimes lead to mesoscopic defects, which are more recurrent than macroscopic defects during the manufacture of complex structural parts. This study deals with the influence of the fabric shear and buckles defects, which appear during draping processes of composite, on the impact behavior of a glass fiber reinforced polymer. To achieve this aim, we produced several specimens with different amplitude of deformations (shear) and defects on the fabric using a specific bench. The specimens were manufactured using the contact molding and tested with several impact energies. The results and measurements made on tested specimens were compared to those of the healthy material. The results showed that the buckle defects have a negative effect on elastic parameters and revealed a larger damage with significant out-of-plane mode relatively to the healthy composite material. This effect is the consequence of a local fiber impoverishment and a disorganization of the fibrous network, with a reorientation of the fibers following the out-of-plane buckling of the yarns, in the area where the defects are located. For the material with calibrated shear of the reinforcement, the increased local fiber rate due to the shear deformations and the contribution to stiffness of the transverse yarns led to an increase in mechanical properties.

Keywords: Defects, Forming, Impact, Induced properties, Textiles

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Authors: Irena Vuković-Kwiatkowska, Halina Kaczmarek

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Poly (lactic acid) is well known polymer, often called green material because of its origin (renewable resources) and biodegradability. This biopolymer can be used in the packaging industry very often. Poor resistance to permeation of gases is the disadvantage of poly (lactic acid). The permeability of gases and vapor through the films applied for packages and bottles generally should be very low to prolong products shelf-life. We propose innovation method of PLA gas barrier modification using electromagnetic radiation in ultraviolet range. Poly (lactic acid) (PLA) and multifunctional acrylate monomers were mixed in different composition. Final films were obtained by photochemical reaction (photocrosslinking). We tested permeability to water vapor and carbon dioxide through these films. Also their resistance to UV radiation was also studied. The samples were conditioned in the activated sludge and in the natural soil to test their biodegradability. An innovative method of PLA modification allows to expand its usage, and can reduce the future costs of waste management what is the result of consuming such materials like PET and HDPE. Implementation of our material for packaging will contribute to the protection of the environment from the harmful effects of extremely difficult to biodegrade materials made from PET or other plastic

Keywords: interpenetrating polymer network, packaging films, photocrosslinking, polyacrylates dipentaerythritol pentaacrylate DPEPA, poly (lactic acid), polymer biodegradation

Procedia PDF Downloads 478

Authors: Chang, Ya-Ju, Hsieh, Pei-Hsin, Wu, Jui-Chuang, Chen-Yang, Yui Whei

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A mesoporous silica material was prepared to apply to the lateral-flow immunochromatography for detecting a model biosample. The probe antibody is immobilized on the silica surface as the test line to capture its affinity antigen, which laterally flows through the chromatography strips. The antigen is labeled with nano-gold particles, such that the detection can be visually read out from the test line without instrument aids. The result reveals that the mesoporous material provides a vast area for immobilizing the detection probes. Biosening surfaces corresponding with a positive proportion of detection signals is obtained with the biosample loading.

Keywords: mesoporous silica, immunochromatography, lateral-flow strips, biosensors, nano-gold particles

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Authors: Xiaoqing Liu, Kurt Friese, Karsten Rinke

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Lacustrine sediment archives rich paleoenvironmental information in lake and surrounding environment. Additionally, modern sediment is used as an effective medium for the monitoring of lake. Organic carbon in sediment is a heterogeneous mixture with varying turnover times and qualities which result from the different biogeochemical processes in the deposition of organic material. Therefore, the isolation of different carbon pools is important for the research of lacustrine condition in the lake. However, the numeric available fractionation procedures can hardly yield homogeneous carbon pools on terms of stability and age. In this work, a multi-step fractionation protocol that treated sediment with hot water, HCl, H2O2 and Na2S2O8 in sequence was adopted, the treated sediment from each step were analyzed for the isotopic and structural compositions with Isotope Ratio Mass Spectrometer coupled with element analyzer (IRMS-EA) and Solid-state 13C Nuclear Magnetic Resonance (NMR), respectively. The sequential extractions with hot-water, HCl, and H2O2 yielded a more homogeneous and C3 plant-originating OC fraction, which was characterized with an atomic C/N ratio shift from 12.0 to 20.8, and 13C and 15N isotopic signatures were 0.9‰ and 1.9‰ more depleted than the original bulk sediment, respectively. Additionally, the H2O2- resistant residue was dominated with stable components, such as the lignins, waxes, cutans, tannins, steroids and aliphatic proteins and complex carbohydrates. 6M HCl in the acid hydrolysis step was much more effective than 1M HCl to isolate a sedimentary OC fraction with higher degree of homogeneity. Owing to the extremely high removal rate of organic matter, the step of a Na2S2O8 oxidation is only suggested if the isolation of the most refractory OC pool is mandatory. We conclude that this multi-step chemical fractionation procedure is effective to isolate more homogeneous OC pools in terms of stability and functional structure, and it can be used as a promising method for OC pools fractionation of sediment or soil in future lake research.

Keywords: 13C-CPMAS-NMR, 13C signature, lake sediment, OC fractionation

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Authors: Parisa Khoshvaght, Mehdi Hosseinzadeh

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During the past few years, the Residue Number System (RNS) has been receiving considerable interest due to its parallel and fault-tolerant properties. This system is a useful tool for Digital Signal Processing (DSP) since it can support parallel, carry-free, high-speed and low power arithmetic. One of the drawbacks of Residue Number System is the fractional numbers, that is, the corresponding circuit is very hard to realize in conventional CMOS technology. In this paper, we propose a method in which the numbers of transistors are significantly reduced. The related delay is extremely diminished, in the first glance we use this method to solve concerning problem of one decimal functional number some how this proposition can be extended to generalize the idea. Another advantage of this method is the independency on the kind of moduli.

Keywords: computer arithmetic, residue number system, number system, one-Hot, VLSI

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Authors: Soledad Carinelli, Iñigo Fernández, José Luis González-Mora, Pedro A. Salazar-Carballo

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Mastitis is the most relevant inflammatory disease in cattle, affecting the animal health and causing important economic losses on dairy farms. This disease takes place in the mammary gland or udder when some opportunistic microorganisms, such as Staphylococcus aureus, Streptococcus agalactiae, Corynebacterium bovis, etc., invade the teat canal. According to the severity of the inflammation, mastitis can be classified as sub-clinical, clinical and chronic. Standard methods for mastitis detection include counts of somatic cells, cell culture, electrical conductivity of the milk, and California test (evaluation of “gel-like” matrix consistency after cell lysed with detergents). However, these assays present some limitations for accurate detection of subclinical mastitis. Currently, haptoglobin, an acute phase protein, has been proposed as novel and effective biomarker for mastitis detection. In this work, an electrochemical biosensor based on polydopamine-modified magnetic nanoparticles (MNPs@pDA) for haptoglobin detection is reported. Thus, MNPs@pDA has been synthesized by our group and functionalized with hemoglobin due to its high affinity to haptoglobin protein. The protein was labeled with specific antibodies modified with alkaline phosphatase enzyme for its electrochemical detection using an electroactive substrate (1-naphthyl phosphate) by differential pulse voltammetry. After the optimization of assay parameters, the haptoglobin determination was evaluated in milk. The strategy presented in this work shows a wide range of detection, achieving a limit of detection of 43 ng/mL. The accuracy of the strategy was determined by recovery assays, being of 84 and 94.5% for two Hp levels around the cut off value. Milk real samples were tested and the prediction capacity of the electrochemical biosensor was compared with a Haptoglobin commercial ELISA kit. The performance of the assay has demonstrated this strategy is an excellent and real alternative as screen method for sub-clinical bovine mastitis detection.

Keywords: bovine mastitis, haptoglobin, electrochemistry, magnetic nanoparticles, polydopamine

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Authors: Zi-Gui Huang, Shen-Hsien Hu

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This study proposes a fabrication of phononic-crystal acoustic wave device. A graphene-like atomic structure was adopted as the main research subject, and a graphene-like structure was designed using piezoelectric material zinc oxide and its periodic boundary conditions were defined using the finite element method. The effects of a hexagonal honeycomb structure were investigated regarding the band gap phenomenon. The use of micro-electromechanical systems process technology to make the film etched micron graphics, designed to produce four kinds of different piezoelectric structure (plat, periodic, single defect and double defects). Frequency response signals and phase change were also measured in this paper.

Keywords: MEMS, phononic crystal, piezoelectric material, Zinc oxide

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Authors: Sonia Sassi, Mostapha Tarfaoui, Hamza Benyahia

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Composite materials are increasingly being used as a substitute for metallic materials in many technological applications like aeronautics, aerospace, marine and civil engineering applications. For composite materials, the thermomechanical response evolves with the strain rate. The energy balance equation for anisotropic, elastic materials includes heat source terms that govern the conversion of some of the kinetic work into heat. The remainder contributes to the stored energy creating the damage process in the composite material. In this paper, we investigate the bulk thermomechanical behavior of adhesively-bonded composite assemblies to quantitatively asses the temperature rise which accompanies adiabatic deformations. In particular, adhesively bonded joints in glass/vinylester composite material are subjected to in-plane dynamic loads under a range of strain rates. Dynamic thermomechanical behavior of this material is investigated using compression Split Hopkinson Pressure Bars (SHPB) coupled with a high speed infrared camera and a high speed camera to measure in real time the dynamic behavior, the damage kinetic and the temperature variation in the material. The interest of using high speed IR camera is in order to view in real time the evolution of heat dissipation in the material when damage occurs. But, this technique does not produce thermal values in correlation with the stress-strain curves of composite material because of its high time response in comparison with the dynamic test time. For this reason, the authors revisit the application of specific thermocouples placed on the surface of the material to ensure the real thermal measurements under dynamic loading using small thermocouples. Experiments with dynamically loaded material show that the thermocouples record temperatures values with a short typical rise time as a result of the conversion of kinetic work into heat during compression test. This results show that small thermocouples can be used to provide an important complement to other noncontact techniques such as the high speed infrared camera. Significant temperature rise was observed in in-plane compression tests especially under high strain rates. During the tests, it has been noticed that sudden temperature rise occur when macroscopic damage occur. This rise in temperature is linked to the rate of damage. The more serve the damage is, a higher localized temperature is detected. This shows the strong relationship between the occurrence of damage and induced heat dissipation. For the case of the in plane tests, the damage takes place more abruptly as the strain rate is increased. The difference observed in the obtained thermomechanical response in plane compression is explained only by the difference in the damage process being active during the compression tests. In this study, we highlighted the dependence of the thermomechanical response on the strain rate of bonded specimens. The effect of heat dissipation of this material cannot hence be ignored and should be taken into account when defining damage models during impact loading.

Keywords: adhesively-bonded composite joints, damage, dynamic compression tests, energy balance, heat dissipation, SHPB, thermomechanical behavior

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Authors: Bharat Kumar, Deepak Kumar, Vijay Chaudhry

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Zirconium alloys exhibit low neutron absorption cross-section and excellent mechanical properties. Due to these unique characteristics, these materials are widely used in designing core components of pressurized heavy water reactors (PHWRs). Another material that is widely used in the design of reactor core is stainless steel. Under operating conditions of the reactor, there are possibilities for mechanical and tribological interaction between the components made of zirconium alloy (Zr-2.5 Nb) and stainless steel (SS-410). This may result in wear of the material. To study the tribological characteristics of Zr-2.5 Nb and SS-410, low amplitude reciprocating wear tests are conducted at room temperature and at high temperatures (260 degrees Celsius). The tests are conducted at frequencies ranging from 5 Hz to 25 Hz. The displacement amplitude is varied from 200 µm to 600 µm. The responses are recorded, analyzed and correlated with damage observed using scanning electron microscopy (SEM) and an optical profilometer. Energy dispersive spectroscopy (EDS) is used to study the damage mechanism prevailing at the contact interface. A higher coefficient of friction (COF) is observed at higher temperatures as compared to the one at room temperature. Tests carried out at high temperature reveals adhesive wear as the dominant mechanism resulting in significant material transfer.

Keywords: PHWRs, Zr-2.5Nb, SS-410, wear

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Authors: Zhengyi Kong, Seung-Eock Kim

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Single angle connections, which are bolted to the beam web and the column flange, are studied to investigate moment-rotation behavior. Elastic–perfectly plastic material behavior is assumed. ABAQUS software is used to analyze the nonlinear behavior of a single angle connection. The same geometric and material conditions with Yanglin Gong’s test are used for verifying finite element models. Since Kishi and Chen’s Power model and Lee and Moon’s Log model are accurate only for a limited range, simpler and more accurate hyperbolic function models are proposed. The equation for calculating rotation at ultimate moment is first proposed.

Keywords: finite element method, moment and rotation, rotation at ultimate moment, single-web angle connections

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Authors: G. H. Li, M. Liu, H. J. Qi, Q. Zhu, W. Z. He

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The drilling and riveting processes are widely used in the assembly of carrier rocket, which makes the efficiency and quality of drilling become the important factor affecting the assembly process. According to the problem existing in the drilling of thick stacked plate (thickness larger than 10mm) of carrier rocket, such as drill break, large noise and burr etc., experimental study of the influence of tool material on the drilling was carried out. The cutting force was measured by a piezoelectric dynamometer, the aperture was measured with an outline projector, and the burr is observed and measured by a digital stereo microscope. Through the measurement, the effects of tool material on the drilling were analyzed from the aspects of drilling force, diameter, and burr. The results show that, compared with carbide drill and coated carbide one, the drilling force of high speed steel is larger. But, the application of high speed steel also has some advantages, e.g. a higher number of hole can be obtained, the height of burr is small, the exit is smooth and the slim burr is less, and the tool experiences wear but not fracture. Therefore, the high speed steel tool is suitable for the drilling of thick stacked plate of 2219 Aluminum alloy.

Keywords: 2219 aluminum alloy, thick stacked plate, drilling, tool material

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Authors: Ashwini Shripatwar, Mayur Biyani, Nikhil Rao, Rajendra Bodake, Sachin Sane

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This paper documents the correlation of valve cover sealing, cracking, and warpage Finite Element Modelling with observations on engine test development. The valve cover is a component mounted on engine head with a gasket which provides sealing against oil which flows around camshaft, valves, rockers, and other overhead components. Material nonlinearity and contact nonlinearity characteristics are taken into consideration because the valve cover is made of a composite material having temperature dependent elastic-plastic properties and because the gasket load-deformation curve is also nonlinear. The leakage is observed between the valve cover and the engine head due to the insufficient contact pressure. The crack is observed on the valve cover due to force application at a region with insufficient stiffness and with elevated temperature. The valve cover shrinkage is observed during the disassembly process on hot exhaust side bolt holes after the engine has been running. In this paper, an analytical approach is developed to correlate a Finite Element Model with the observed failures and to address the design issues associated with the failure modes in question by making design changes in the model.

Keywords: cracking issue, gasket sealing analysis, nonlinearity of contact and material, valve cover

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Authors: Pablo Lopez Hurtado, Antroine Rouilly, Virginie Vandenbossche

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Cellulose fibre insulation is an eco-friendly building material made from recycled paper fibres, treated with borates for fungal and fire resistance. It is comparable in terms of thermal and acoustic performance to mineral wool insulation and other insulation materials based on non-renewable resources. The main method of application consists in separating and blowing the fibres in attics or closed wall cavities. Another method, known as the “wet spray method” is gaining interest. With this method the fibres are projected with pulverized water, which stick to the wall cavities. The issue with the wet spray technique is that the water dosage could be difficult to control. A high water dosage implies not only a longer drying time, depending on ambient conditions, but also a change in the performance of the material itself. In our work we studied the thermal and mechanical properties of wet spray-cellulose insulation in order to understand how water dosage could affect these properties. The material was first characterized to study the chemical and physical properties of the fibres. Then representative samples of wet sprayed cellulose with varying applied water dosage were subject to thermal conductivity and compression testing in order to better understand how changes in the fibres induced by drying can affect these properties.

Keywords: cellulose fibre, recycled paper, moisture sorption, thermal insulation

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Authors: Q. Ni, J. A. Serna, D. Holland, X. Wang

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The objective of this study is to develop Nuclear Magnetic Resonance (NMR) techniques to enhance bone related research applied on normal and disuse (Biglycan knockout) mice bone in vitro by using both low-field and high-field NMR simultaneously. It is known that the total amplitude of T₂ relaxation envelopes, measured by the Carr-Purcell-Meiboom-Gill NMR spin echo train (CPMG), is a representation of the liquid phase inside the pores. Therefore, the NMR CPMG magnetization amplitude can be transferred to the volume of water after calibration with the NMR signal amplitude of the known volume of the selected water. In this study, the distribution of mobile water, porosity that can be determined by using low-field (20 MHz) CPMG relaxation technique, and the pore size distributions can be determined by a computational inversion relaxation method. It is also known that the total proton intensity of magnetization from the NMR free induction decay (FID) signal is due to the water present inside the pores (mobile water), the water that has undergone hydration with the bone (bound water), and the protons in the collagen and mineral matter (solid-like protons). Therefore, the components of total mobile and bound water within bone that can be determined by low-field NMR free induction decay technique. Furthermore, the bound water in solid phase (mineral and organic constituents), especially, the dominated component of calcium hydroxyapatite (Ca₁₀(OH)₂(PO₄)₆) can be determined by using high-field (400 MHz) magic angle spinning (MAS) NMR. With MAS technique reducing NMR spectral linewidth inhomogeneous broadening and susceptibility broadening of liquid-solid mix, in particular, we can conduct further research into the ¹H and ³¹P elements and environments of bone materials to identify the locations of bound water such as OH- group within minerals and bone architecture. We hypothesize that with low-field and high-field magic angle spinning NMR can provide a more complete interpretation of water distribution, particularly, in bound water, and these data are important to access bone quality and predict the mechanical behavior of bone.

Keywords: bone, mice bone, NMR, water in bone

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Authors: Priyanka Kumari Gupta, Punya Prasanna Paltani, Shrivishal Tripathi

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This paper proposes a nonlinear photonic crystal ring resonator-based all-optical 2 × 2 switch. The nonlinear Kerr effect is used to evaluate the essential 2 x 2 components of the photonic crystal-based optical switch, including the bar and cross states. The photonic crystal comprises a two-dimensional square lattice of dielectric rods in an air background. In the background air, two different dielectric materials are used for this comparison study separately. Initially with chalcogenide glass rods, then with GaAs rods. For both materials, the operating wavelength, bandgap diagram, operating power intensities, and performance parameters, such as the extinction ratio, insertion loss, and cross-talk of an optical switch, have also been estimated using the plane wave expansion and the finite-difference time-domain method. The chalcogenide glass material (Ag20As32Se48) has a high refractive index of 3.1 which is highly suitable for switching operations. This dielectric material is immersed in an air background with a nonlinear Kerr coefficient of 9.1 x 10-17 m2/W. The resonance wavelength is at 1552 nm, with the operating power intensities at the cross-state and bar state around 60 W/μm2 and 690 W/μm2. The extinction ratio, insertion loss, and cross-talk value for the chalcogenide glass at the cross-state are 17.19 dB, 0.051 dB, and -17.14 dB, and the bar state, the values are 11.32 dB, 0.025 dB, and -11.35 dB respectively. The gallium arsenide (GaAs) dielectric material has a high refractive index of 3.4, a direct bandgap semiconductor material highly preferred nowadays for switching operations. This dielectric material is immersed in an air background with a nonlinear Kerr coefficient of 3.1 x 10-16 m2/W. The resonance wavelength is at 1558 nm, with the operating power intensities at the cross-state and bar state around 110 W/μm2 and 200 W/μm2. The extinction ratio, insertion loss, and cross-talk value for the chalcogenide glass at the cross-state are found to be 3.36.19 dB, 2.436 dB, and -5.8 dB, and for the bar state, the values are 15.60 dB, 0.985 dB, and -16.59 dB respectively. This paper proposes an all-optical 2 × 2 switch based on a nonlinear photonic crystal using a ring resonator. The two-dimensional photonic crystal comprises a square lattice of dielectric rods in an air background. The resonance wavelength is in the range of photonic bandgap. Later, another widely used material, GaAs, is also considered, and its performance is compared with the chalcogenide glass. Our presented structure can be potentially applicable in optical integration circuits and information processing.

Keywords: photonic crystal, FDTD, ring resonator, optical switch

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Authors: Elmo Thiago Lins Cöuras Ford, Valentina Alessandra Carvalho do Vale, Rubens Maribondo do Nascimento, José Ubiragi de Lima Mendes

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Given the unquestionable need of environmental preservation of discarded industrial residues, The scrape of tires have been seen as a salutary alternative for addictive in concrete, asphalt production and of other composites materials. In this work, grew a composite the base of scrape of tire as reinforcement and latex as matrix, to be used as insulating thermal in "cold" systems (0º). Analyzed the acting of the material was what plays the thermal conservation when submitted the flow of heat. Verified the temperature profiles in the internal surfaces and it expresses of the composite as well as the temperature gradient in the same. As a consequence, in function of the answers of the system, conclusions were reached.

Keywords: cold system, latex, flow of heat, asphalt production

Procedia PDF Downloads 462

Authors: Krishna Nand, Mohammad Taufik

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Fused Filament Fabrication (FFF) is one of the most popular additive manufacturing (AM) technology. In FFF technology, a wire form material (filament) is fed inside a heated chamber, where it gets converted into semi-solid form and extruded out of a nozzle to be deposited on the build platform to fabricate the part. FFF technology is expanding and covering the market at a very rapid rate, so the need of raw materials for 3D printing is also increasing. The cost of 3D printing is directly affected by filament cost. To make 3D printing more economic, a compact and portable filament/wire extrusion system is needed. Wire extrusion systems to extrude ordinary wire/filament made of a single material are available in the market. However, extrusion system to make a composite wire/filament are not available. Hence, in this study, initial efforts have been made to develop a table-top composite wire extruder. The developed system is consisted of mechanical parts, electronics parts, and a control system. A multiple channel hopper, extrusion screw, melting chamber and nozzle, cooling zone, and spool winder are some mechanical parts. While motors, heater, temperature sensor, cooling fans are some electronics parts, which are used to develop this system. A control board has been used to control the various process parameters like – temperature and speed of motors. For the production of composite wire/filament, two different materials could be fed through two channels of hopper, which will be mixed and carried to the heated zone by extrusion screw. The extrusion screw is rotated by a motor, and the speed of this motor will be controlled by the controller as per the requirement of material extrusion rate. In the heated zone, the material will melt with the help of a heating element and extruded out of the nozzle in the form of wire. The developed system occupies less floor space due to the vertical orientation of its heating chamber. It is capable to extrude ordinary filament as well as composite filament, which are compatible with 3D printers available in the market. Further, the developed system could be employed in the research and development of materials, processing, and characterization for 3D printer. The developed system presented in this study could be a better choice for hobbyists and researchers dealing with the fused filament fabrication process to reduce the 3D printing cost significantly by recycling the waste material into 3D printer feed material. Further, it could also be explored as a better alternative for filament production at the commercial level.

Keywords: additive manufacturing, 3D Printing, filament extrusion, pellet extrusion

Procedia PDF Downloads 168

Authors: Claudia L. Bianchi, Giuseppina Cerrato, Federico Galli, Federica Minozzi, Valentino Capucci

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At the beginning of the industrial productions, porcelain gres tiles were considered as just a technical material, aesthetically not very beautiful. Today thanks to new industrial production methods, both properties, and beauty of these materials completely fit the market requests. In particular, the possibility to prepare slabs of large sizes is the new frontier of building materials. Beside these noteworthy architectural features, new surface properties have been introduced in the last generation of these materials. In particular, deposition of TiO₂ transforms the traditional ceramic into a photocatalytic eco-active material able to reduce polluting molecules present in air and water, to eliminate bacteria and to reduce the surface dirt thanks to the self-cleaning property. The problem of photocatalytic materials resides in the fact that it is necessary a UV light source to activate the oxidation processes on the surface of the material, processes that are turned off inexorably when the material is illuminated by LED lights and, even more so, when we are in darkness. First, it was necessary a thorough study change the existing plants to deposit the photocatalyst very evenly and this has been done thanks to the advent of digital printing and the development of an ink custom-made that stabilizes the powdered TiO₂ in its formulation. In addition, the commercial TiO₂, which is used for the traditional photocatalytic coating, has been doped with metals in order to activate it even in the visible region and thus in the presence of sunlight or LED. Thanks to this active coating, ceramic slabs are able to purify air eliminating odors and VOCs, and also can be cleaned with very soft detergents due to the self-cleaning properties given by the TiO₂ present at the ceramic surface. Moreover, the presence of dopant metals (patent WO2016157155) also allows the material to work as well as antibacterial in the dark, by eliminating one of the negative features of photocatalytic building materials that have so far limited its use on a large scale. Considering that we are constantly in contact with bacteria, some of which are dangerous for health. Active tiles are 99,99% efficient on all bacteria, from the most common such as Escherichia coli to the most dangerous such as Staphilococcus aureus Methicillin-resistant (MRSA). DIGITALIFE project LIFE13 ENV/IT/000140 – award for best project of October 2017.

Keywords: Ag-doped microsized TiO₂, eco-active ceramic, photocatalysis, digital coating

Procedia PDF Downloads 229

Authors: R. Bensaada, M. Almansba, M. Ould Ouali, R. Ferhoum, N. E. Hannachi

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The aim of this work is to simulate the ductile fracture of SEN specimens in aluminium alloy. The assessment of fracture toughness is performed with the calculation of Jc (the critical value of J-Integral) through the resistance curves. The study is done using finite element code calculation ABAQUSTM including an elastic plastic with damage model of material’s behaviour. The procedure involves specimens of four different thicknesses and four ligament sizes for every thickness. The material of study is an aluminium alloy 6061-T6 for which the necessary parameters to complete the study are given. We found the same results for the same specimen’s thickness and for different ligament sizes when the fracture criterion is evaluated.

Keywords: j-integral, critical-j, damage, fracture toughness

Procedia PDF Downloads 359

Authors: Uliana N. Tumanova, Sergey M. Voevodin, Veronica A. Sinitsyna, Alexandr I. Shchegolev

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An important part of forensic and autopsy research in perinatology is the answer to the question of life and stillbirth. Postmortem magnetic resonance imaging (MRI) is an objective non-invasive research method that allows to store data for a long time and not to exhume the body to clarify the diagnosis. The purpose of the research is to study the possibilities of a postmortem MRI to determine the stillbirth and death of a newborn who had spontaneous breathing and died on the first day after birth. MRI and morphological data of a study of 23 stillborn bodies, prenatally dead at a gestational age of 22-39 weeks (Group I) and the bodies of 16 newborns who died from 2 to 24 hours after birth (Group II) were compared. Before the autopsy, postmortem MRI was performed on the Siemens Magnetom Verio 3T device in the supine position of the body. The control group for MRI studies consisted of 7 live newborns without lung disease (Group III). On T2WI in the sagittal projection was measured MR-signal intensity (SI) in the lung tissue (L) and shoulder muscle (M). During the autopsy, a pulmonary swimming test was evaluated, and macro- and microscopic studies were performed. According to the postmortem MRI, the highest values of mean SI of the lung (430 ± 27.99) and of the muscle (405.5 ± 38.62) on T2WI were detected in group I and exceeded the corresponding value of group II by 2.7 times. The lowest values were found in the control group - 77.9 ± 12.34 and 119.7 ± 6.3, respectively. In the group II, the lung SI was 1.6 times higher than the muscle SI, whereas in the group I and in the control group, the muscle SI was 2.1 times and 1.8 times larger than the lung. On the basis of clinical and morphological data, we calculated the formula for determining the breathing index (BI) during postmortem MRI: BI = SIL x SIM / 100. The mean value of BI in the group I (1801.14 ± 241.6) (values ranged from 756 to 3744) significantly higher than the corresponding average value of BI in the group II (455.89 ± 137.32, p < 0.05) (305-638.4). In the control group, the mean BI value was 91.75 ± 13.3 (values ranged from 53 to 154). The BI with the results of pulmonary swimming tests and microscopic examination of the lungs were compared. The boundary value of BI for the differential diagnosis of stillborn and newborn death was 700. Using the postmortem MRI allows to differentiate the stillborn with the death of the breathing newborn.

Keywords: lung, newborn, postmortem MRI, stillborn

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Authors: M. R. Ashok, S. Srivatsan, S. Vignesh

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Common replacement for glass in composites is the Glass Fiber Reinforced Plastics (GFRP). The GFRP has its own advantages for being a good alternative. The purpose of this research is to find a suitable enhancement for the commonly used composite Glass Fiber Reinforced Plastics (GFRP). The goal is to enhance the material properties of the composite by providing a suitable matrix with Al base. The various mechanical tests are performed to analyze and compare the improvement in the mechanical properties of the composite. As a result, this material can be used as an alternative for the commonly used GFRP in various fields with increased effectiveness in its functioning.

Keywords: alloy based composites, composite materials, glass fiber reinforced plastics, sSuper composites

Procedia PDF Downloads 334