Search results for: strain localization

Authors: Sarah K. Hagi, Majdi Alnowaimi

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In the last decade, there were immense advancements in the medical imaging modalities. These advancements can scan a whole volume of the lung organ in high resolution images within a short time. According to this performance, the physicians can clearly identify the complicated anatomical and pathological structures of lung. Therefore, these advancements give large opportunities for more advance of all types of lung cancer treatment available and will increase the survival rate. However, lung cancer is still one of the major causes of death with around 19% of all the cancer patients. Several factors may affect survival rate. One of the serious effects is the breathing process, which can affect the accuracy of diagnosis and lung tumor treatment plan. We have therefore developed a semi automated algorithm to localize the 3D lung tumor positions across all respiratory data during respiratory motion. The algorithm can be divided into two stages. First, a lung tumor segmentation for the first phase of the 4D computed tomography (CT). Lung tumor segmentation is performed using an active contours method. Then, localize the tumor 3D position across all next phases using a 12 degrees of freedom of an affine transformation. Two data set where used in this study, a compute simulate for 4D CT using extended cardiac-torso (XCAT) phantom and 4D CT clinical data sets. The result and error calculation is presented as root mean square error (RMSE). The average error in data sets is 0.94 mm ± 0.36. Finally, evaluation and quantitative comparison of the results with a state-of-the-art registration algorithm was introduced. The results obtained from the proposed localization algorithm show a promising result to localize alung tumor in 4D CT data.

Keywords: automated algorithm , computed tomography, lung tumor, tumor localization

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Authors: Xing Ping Hu, Yuexun Tian, Jerome Hogsette

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Housefly, Musca domestica L., is a serious urban nuisance and public health/food safety concern. This study evaluated the topical toxicity of 17 essential oil components and 3 plant essential oils against permethrin-resistant adult females and insecticide-susceptible house fly strains. Results show that thymol had the lowest LD₅₀ values against permethrin-resistant strain (43.77 and 41.10 ug per fly) and permethrin-susceptible strain (35.19 and 29.16 ug per fly) at both 24- and 48-hours post treatments; (+)-Pulegone had the lowest LD₉₅ values against the permethrin-resistant strain (0.15 and 0.10 mg per fly) at 24- and 48-hours post treatments, whereas plant thyme oil had the lowest LD₉₅ value of 0.17 mg per fly at post-24h and post-48h against the permethrin-susceptible strain. Additionally, the LD₅₀s was slightly but not significantly negatively correlated with the boiling points of the compounds tested; but showed no correlation with the density and LogP. These results indicate that specific essential oils and compounds have topical insecticidal properties against house flies with low dose. They may have the potential for development as botanical insecticides.

Keywords: urban pest, public health, pest management, botanical chemical

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Authors: Subodh Nath Patel, Raja Raman, Mananshi Adhikary, Jitendra Mathur, Sandip Bhattacharyya

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The composition adjustment by sealed argon bubbling–oxygen blowing (CAS-OB) process is a process designed for adjusting steel composition and temperature during secondary metallurgy. One of the equipment in the said process is a snorkel or bell, fixed to a movable bracket. Snorkel serves the purpose of feeding ferroalloys into the liquid metal simultaneously removing gases to the gas cleaning system through its port at its top. The bell-shaped snorkel consists of two parts. The upper part has an inside liner, and the lower part is lined on both side with high-alumina castable reinforced with 2% stainless steel needles. Both the parts are coupled with a flange bolt system. These flanges were found to get buckled during operation, and the gap was generating between them. This problem was chronic since its. It was expected to give a life of 80 heats, but it was failing within 45-50 heats. After every 25-30 heats, it had to be repaired by changing and/or tightening its nuts and bolts. Visual observation, microstructural analysis through optical microscopes and SEM, hardness measurement and thermal strain calculation were carried out to find out the root cause of this problem. The calculated thermal strain was compared with actual thermal strain; comparison of the two revealed that thermal strain was responsible for buckling. Finite element analysis (FEA) was carried out to reaffirm the effect temperature on the flanges. FEA was also used in the modification in the design of snorkel flange to accommodate thermal strain. Thermal insulation was also recommended which increased its life from 45 heats to 65 heats, impacting business process positively.

Keywords: CAS OB process, finite element analysis, snorkel, thermal strain

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Authors: Prashant Motwani, Arghadeep Laskar

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The transfer of prestress force from prestressing strands to the surrounding concrete is dependent on the bond between the two materials. It is essential to understand the actual bond stress distribution along the transfer length to determine the transfer zone in pre-tensioned concrete. A 3-D nonlinear finite element model has been developed to simulate the transfer of prestress force from steel to concrete in pre-tensioned bridge girders through thermal strain technique using commercially available package ABAQUS. Full-scale bridge girder has been analyzed with thermal strain approach where the damage plasticity constitutive model has been used to model concrete. Parameters such as concrete strain, effective prestress, upward camber and longitudinal stress have been compared with analytical results. The discrepancy between numerical and analytical values was within 20%. The paper also presents a convergence study on mesh density and aspect ratio of the elements to perform the finite element study.

Keywords: aspect ratio, bridge girder, centre of gravity of strand, mesh density, finite element model, pretensioned bridge girder

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Authors: Fatna Benmessaoud, Mohammed Cheikh, Vencent Velay, Vanessa Vidal, Farhad Rezai-Aria, Christine Boher

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Ti-6Al-4V titanium alloy is one of the most widely used materials in aeronautical and aerospace industries. Because of its high specific strength, good fatigue, and corrosion resistance, this alloy is very suitable for moderate temperature applications. At room temperature, Ti-6Al-4V mechanical behavior is generally controlled by the behavior of alpha phase (beta phase percent is less than 8%). The plastic strain of this phase notably based on crystallographic slip can be hindered by various obstacles and mechanisms (crystal lattice friction, sessile dislocations, strengthening by solute atoms and grain boundaries…). The grains aspect of alpha phase (its morphology and texture) and the nature of its crystallographic lattice (which is hexagonal compact) give to plastic strain heterogeneous, discontinuous and anisotropic characteristics at the local scale. The aim of this work is to develop a multi-scale model for Ti-6Al-4V mechanical behavior using crystal plasticity approach; this multi-scale model is used then to investigate grains size, dispersion of grains size, crystallographic texture and slip systems activation effects on Ti-6Al-4V mechanical behavior under monotone quasi-static loading. Nine representative elementary volume (REV) are built for taking into account the physical elements (grains size, dispersion and crystallographic) mentioned above, then boundary conditions of tension test are applied. Finally, simulation of the mechanical behavior of Ti-6Al-4V and study of slip systems activation in alpha phase is reported. The results show that the macroscopic mechanical behavior of Ti-6Al-4V is strongly linked to the active slip systems family (prismatic, basal or pyramidal). The crystallographic texture determines which family of slip systems can be activated; therefore it gives to the plastic strain a heterogeneous character thus an anisotropic macroscopic mechanical behavior of Ti-6Al-4V alloy modeled. The grains size influences also on mechanical proprieties of Ti-6Al-4V, especially on the yield stress; by decreasing of the grain size, the yield strength increases. Finally, the grains' distribution which characterizes the morphology aspect (homogeneous or heterogeneous) gives to the deformation fields distribution enough heterogeneity because the crystallographic slip is easier in large grains compared to small grains, which generates a localization of plastic deformation in certain areas and a concentration of stresses in others.

Keywords: multi-scale modeling, Ti-6Al-4V alloy, crystal plasticity, grains size, crystallographic texture

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Authors: Mikhail O. Eremin

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Seismic activity around the world is clearly a threat to people's lives, as well as infrastructure and capital construction. It is the instability of the latter to powerful earthquakes that most often causes human casualties. Therefore, during construction it is necessary to take into account the risks of large-scale natural disasters. The task of assessing the risks of natural disasters is one of the most urgent at the present time. The final goal of any study of earthquakes is forecasting. This is especially important for seismically active regions of the planet where earthquakes occur frequently. Gorni Altai is one of such regions. In work, we developed the physical-mathematical model of stress-strain state evolution of loaded geomedium with the purpose of numerical simulation of seismic process accompanying the formation of Chuya-Kuray fault zone Gorni Altay, Russia. We build a structural model on the base of seismotectonic and paleoseismogeological investigations, as well as SRTM-data. Base of mathematical model is the system of equations of solid mechanics which includes the fundamental conservation laws and constitutive equations for elastic (Hooke's law) and inelastic deformation (modified model of Drucker-Prager-Nikolaevskii). An initial stress state of the model correspond to gravitational. Then we simulate an activation of a buried dextral strike-slip paleo-fault located in the basement of the model. We obtain the stages of formation and the structure of Chuya-Kuray fault zone. It is shown that results of numerical simulation are in good agreement with field observations in statistical sense. Simulated seismic process is strongly bound to the faults - lineaments with high degree of inelastic strain localization. Fault zone represents en-echelon system of dextral strike-slips according to the Riedel model. The system of surface lineaments is represented with R-, R'-shear bands, X- and Y-shears, T-fractures. Simulated seismic process obeys the laws of Gutenberg-Richter and Omori. Thus, the model describes a self-similar character of deformation and fracture of rocks and geomedia. We also modified the algorithm of determination of separate slip events in the model due to the features of strain rates dependence vs time.

Keywords: Drucker-Prager model, fault zone, numerical simulation, Riedel bands, seismic process, strike-slip fault

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Authors: Ahmad Idi

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The biosynthesis and properties of polyhydroxyalkanoate (PHA) are determined by the bacterial strain and the culture condition. Hence this study elucidates the structure and properties of PHA produced by a newly isolated strain of photosynthetic bacterium, Rhodobacter sphaeroides ADZ101 grown under the optimized culture condition. The properties of the accumulated PHA were determined via FTIR, NMR, TGA, and GCMS analyses. The results showed that acetate and ammonia chloride had the highest PHA accumulation with a ratio of 32.5 mM at neutral pH. The structural analyses showed that the polymer comprises both short and medium-chain length monomers ranging from C5, C13, C14, and C18, as well as the presence of novel PHA monomers. The thermal analysis revealed that the maximum temperature of decomposition occurred at 395°C and 454°C, indicating two major decomposition reactions. Thus this bacterial strain, optimized culture condition, and the abundance of novel monomers enhanced the thermostability of the accumulated PHA.

Keywords: bioplastic polyhydroxyalkanoates Rhodobacter sphaeroides ADZ101 thermostable PHA

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Authors: Ana Pego

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Environmental technologies were developed for decades. Clean technologies emerged a few years ago. In these perspectives, the use of cleantech technologies has become very important due the fact of new era of environmental feats. As such, the market itself has become more competitive, more collaborative towards a better use of clean technologies. This paper shows the importance of clean technologies in offshore energy sector in Portuguese market, its localization and its impact on economy. Clean technologies are directly related with renewable cluster and concomitant with economic and social resource optimization criteria, geographic aspects, climate change and soil features. Cleantech is related with regional development, socio-technical transitions in organisations. There are an economical and social combinations which allow specialisation of regions in activities, higher employment, reduce of energy costs, local knowledge spillover and, business collaboration and competitiveness. The methodology used will be quantitative (IO matrix for Portugal 2013) and qualitative (questionnaires to stakeholders). The mix of both methodologies will confirm whether the use of technologies will allow a positive impact on economic and social variables used on this model. It is expected a positive impact on Portuguese economy both in investment and employment taking in account the localization of offshore renewable activities. This means that the importance of offshore renewable investment in Portugal has a few points which should be pointed out: the increase of specialised employment, localization of specific activities in territory, and increase of value added in certain regions. The conclusion will allow researchers and organisation to compare the Portuguese model to other European regions in order to a better use of natural and human resources.

Keywords: cleantech, economic impact, localisation, territory dynamics

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Authors: Aboussalih Amira, Zarza Tahar, Fedaoui Kamel, Hammoudi Saleh

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This work focuses on the simulation of the prediction of the behaviour of austenitic stainless steel (SS) 304L under complex loading in stress and imposed strain. The Chaboche model is a cable to describe the response of the material by the combination of two isotropic and nonlinear kinematic work hardening, the model is implemented in the ZébuLon computer code. First, we represent the evolution of the axial stress as a function of the plastic strain through hysteresis loops revealing a hardening behaviour caused by the increase in stress by stress in the direction of tension/compression. In a second step, the study of the ratcheting phenomenon takes a key place in this work by the appearance of the average stress. In addition to the solicitation of the material in the biaxial direction in traction / torsion.

Keywords: damage, 304L, Ratcheting, plastic strain

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Authors: A. Hocine, A. Ghouaoula, S. M. Medjdoub, M. Cherifi

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The present paper proposed a meso–macro model describing the mechanical behaviour composite laminates of staking sequence [+θ/-θ]s under tensil loading. The behaviour of a layer is ex-pressed through elasticity coupled to damage. The elastic strain is due to the elasticity of the layer and can be modeled by using the classical laminate theory, and the laminate is considered as an orthotropic material. This means that no coupling effect between strain and curvature is considered. In the present work, the damage is associated to cracking of the matrix and parallel to the fibers and it being taken into account by the changes in the stiffness of the layers. The anisotropic damage is completely described by a single scalar variable and its evolution law is specified from the principle of maximum dissipation. The stress/strain relationship is investigated in plane stress loading.

Keywords: damage, behavior modeling, meso-macro model, composite laminate, membrane loading

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Authors: Kim Alvin De Lara

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The research aimed to assess the level of acceptability of the developed activity sheets in Science 5 integrating climate change adaptation of grade 5 science teachers in the District of Pililla school year 2016-2017. In this research, participants were able to recognize and understand the importance of environmental education in improving basic education and integrating them in lessons through localization and contextualization. The researcher conducted the study to develop a material to use by Science teachers in Grade 5. It served also as a self-learning resource for students. The respondents of the study were the thirteen Grade 5 teachers teaching Science 5 in the District of Pililla. Respondents were selected purposively and identified by the researcher. A descriptive method of research was utilized in the research. The main instrument was a checklist which includes items on the objectives, content, tasks, contextualization and localization of the developed activity sheets. The researcher developed a 2-week lesson in Science 5 for 4th Quarter based on the curriculum guide with integration of climate change adaptation. The findings revealed that majority of respondents are female, 31 years old and above, 10 years above in teaching science and have units in master’s degree. With regards to the level of acceptability, the study revealed developed activity sheets in science 5 is very much acceptable. In view of the findings, lessons in science 5 must be contextualized and localized to improve to make the curriculum responds, conforms, reflects, and be flexible to the needs of the learners, especially the 21st century learners who need to be holistically and skillfully developed. As revealed by the findings, it is more acceptable to localized and contextualized the learning materials for pupils. Policy formation and re-organization of the lessons and competencies in Science must be reviewed and re-evaluated. Lessons in science must also be integrated with climate change adaptation since nowadays, people are experiencing change in climate due to global warming and other factors. Through developed activity sheets, researcher strongly supports environmental education and believes this to serve as a way to instill environmental literacy to students.

Keywords: activity sheets, climate change adaptation, contextualization, localization

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Authors: Reza Rezaeipour Honarmandzad

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In this paper we propose an ANN for detection and localization of fatigue damage in aircraft structures. We used network of piezoelectric transducers for Lamb-wave measurements in order to calculate damage indices. Data gathered by the sensors was given to neural network classifier. A set of neural network electors of different architecture cooperates to achieve consensus concerning the state of each monitored path. Sensed signal variations in the ROI, detected by the networks at each path, were used to assess the state of the structure as well as to localize detected damage and to filter out ambient changes. The classifier has been extensively tested on large data sets acquired in the tests of specimens with artificially introduced notches as well as the results of numerous fatigue experiments. Effect of the classifier structure and test data used for training on the results was evaluated.

Keywords: ANN, fatigue damage, aircraft structures, piezoelectric transducers, lamb-wave measurements

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Authors: Daniel Pastor, Hyo-Sang Shin

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This paper presents a novel method to use optical flow navigation for long-term navigation. Unlike standard SLAM approaches for augmented reality, OFLAAM is designed for Micro Air Vehicles (MAV). It uses an optical flow camera pointing downwards, an IMU and a monocular camera pointing frontwards. That configuration avoids the expensive mapping and tracking of the 3D features. It only maps these features in a vocabulary list by a localization module to tackle the loss of the navigation estimation. That module, based on the well-established algorithm DBoW2, will be also used to close the loop and allow long-term navigation in confined areas. That combination of high-speed optical flow navigation with a low rate localization algorithm allows fully autonomous navigation for MAV, at the same time it reduces the overall computational load. This framework is implemented in ROS (Robot Operating System) and tested attached to a laptop. A representative scenarios is used to analyse the performance of the system.

Keywords: vision, UAV, navigation, SLAM

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Authors: Wang Jianguo, Ding Xiao, Liu Dong, Wang Haiping, Yang Yanhui, Hu Yang

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The hot deformation behavior of Inconel 718 alloy was studied by uniaxial compression tests under the deformation temperature of 940~1040℃ and strain rate of 0.001-10s⁻¹. The double cone compression (DCC) tests develop strains range from 30% to the 79% strain including all intermediate values of stains at different temperature (960~1040℃). DCC tests were simulated by finite element software which shown the strain and strain rates distribution. The result shows that the peak stress level of the alloy decreased with increasing deformation temperature and decreasing strain rate, which could be characterized by a Zener-Hollomon parameter in the hyperbolic-sine equation. The characterization method of hot processing window containing recrystallization volume fraction and average grain size was proposed for double cone compression test of uniform coarse grain, mixed crystal and uniform fine grain double conical specimen in hydraulic press and screw press. The results show that uniform microstructures can be obtained by low temperature with high deformation followed by high temperature with small deformation on the hydraulic press and low temperature, medium deformation, multi-pass on the screw press. The two methods were applied in industrial forgings process, and the forgings with uniform microstructure were obtained successfully.

Keywords: inconel 718 superalloy, hot processing windows, double cone compression, uniform microstructure

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Authors: Michael Dare Asemoloye, Segun Gbolagade Jonathan, Rafiq Ahmad, Odunayo Joseph Olawuyi, D. O. Adejoye

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Fungi have potentials for degrading hydrocarbons through the secretion of different enzymes. Crude oil tolerance and degradation by Trichoderma harzianum was investigated in this study with its ability to produce peroxidase enzymes (LiP and MnP). Many fungal strains were isolated from rhizosphere of grasses growing on a crude oil spilled site, and the most frequent strain based on percentage incidence was further characterized using morphological and molecular characteristics. Molecular characterization was done through the amplification of Ribosomal-RNA regions of 18s (1609-1627) and 28s (287-266) using ITS1 and ITS4 combinations and it was identified using NCBI BLAST tool. The selected fungus was also subjected to an in-vitro tolerance test at crude oil concentrations of 5, 10, 15, 20 and 25% while 0% served as control. In addition, lignin peroxidase genes (lig1-6) and manganese peroxidase gene (mnp) were detected and expressed in this strain using RT-PCR technique, its peroxidase producing activities was also studied in aliquots (U/ml). This strain had highest incidence of 80%, it was registered in NCBI as Trichoderma harzianum asemoJ KY488466. The strain KY488466 responded to crude oil concentrations as it increase, the dose inhibition response percentage (DIRP) increased from 41.67 to 95.41 at 5 to 25 % crude oil concentrations. All the peroxidase genes are present in KY488466, and expressed with amplified 900-1000 bp through RT-PCR technique. In this strain, lig2, lig4 and mnp genes were over-expressed, lig 6 was moderately expressed, while none of the genes was under-expressed. The strain also produced 90±0.87 U/ml lignin peroxidase and 120±1.23 U/mil manganese peroxidase enzymes in aliquots. These results imply that KY488466 can tolerate and survive high crude oil concentration and could be exploited for bioremediation of oil-spilled soils, the produced peroxidase enzymes could also be exploited for other biotechnological experiments.

Keywords: crude oil, enzymes, expression, peroxidase genes, tolerance, Trichoderma harzianum

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Authors: Suman Paik, P. V. Durgaprasad, Bijan K. Dutta

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A study combining experimental and numerical investigation on the deformation behaviour of single crystals of copper is presented in this paper. Cylindrical samples were cut in specific orientations from high purity copper single crystal and subjected to uniaxial compression loading at quasi-static strain rate. The stress-strain curves along two different crystallographic orientations were then extracted. In order to study and compare the deformation responses, a single crystal plasticity model incorporating non-Schmid effects was developed assuming cross-slip plays an important role in orientation of the material. By making use of crystal plasticity finite element method, the model was applied to investigate the orientation dependence of the stress-strain behaviour of two crystallographic orientations. Finally, details of slip activities of deformed crystals were investigated by linking the orientation of slip lines with the theoretical traces of possible crystallographic planes. The experimentally determined active slip modes were matched with those determined by simulations.

Keywords: crystal plasticity, modelling, non-Schmid effects, finite elements, finite strain

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Authors: K. Khelil, H. Ammar, K. Saouchi

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Fiber Bragg Grating (FBG) structure is an periodically modulated optical fiber. It acts as a selective filter of wavelength whose reflected peak is called Bragg wavelength and it depends on the period of the fiber and the refractive index. The simulation of FBG is based on solving the Coupled Mode Theory equation by using the Transfer Matrix Method which is carried out using MATLAB. It is found that spectral reflectivity is shifted when the change of temperature and strain is uniform. Under non-uniform temperature or strain perturbation, the spectrum is both shifted and destroyed. In case of transverse loading, reflectivity spectrum is split into two peaks, the first is specific to X axis, and the second belongs to Y axis. FBGs are used in civil engineering to detect perturbations applied to buildings.

Keywords: Bragg wavelength, coupled mode theory, optical fiber, temperature measurement

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Authors: William Fuentes, Melany Gil

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Numerical simulations of offshore wind turbines (OWTs) in shallow waters demand sophisticated models considering the cyclic nature of the environmental loads. For the case of an OWT founded on sands, rapid loading may cause a reduction of the effective stress of the soil surrounding the structure. This eventually leads to its settlement, tilting, or other issues affecting its serviceability. In this work, a 3D FE model of an OWT founded on sand is constructed and analyzed. Cyclic loading with different histories is applied at certain points of the tower to simulate some environmental forces. The mechanical behavior of the soil is simulated through the recently proposed ISA-hypoplastic model for sands. The Intergranular Strain Anisotropy ISA can be interpreted as an enhancement of the intergranular strain theory, often used to extend hypoplastic formulations for the simulation of cyclic loading. In contrast to previous formulations, the proposed constitutive model introduces an elastic range for small strain amplitudes, includes the cyclic mobility effect and is able to capture the cyclic behavior of sands under a larger number of cycles. The model performance is carefully evaluated on the FE dynamic analysis of the OWT.

Keywords: offshore wind turbine, monopile, ISA, hypoplasticity

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Authors: Sifeddine Abderrahmani, Sonia Bouafia

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The finite element method is the most practical tool for the analysis of structures, whatever the geometrical shape and behavior. It is extensively used in many high-tech industries, such as civil or military engineering, for the modeling of bridges, motor bodies, fuselages, and airplane wings. Additionally, experience demonstrates that engineers like modeling their structures using the most basic finite elements. Numerous models of finite elements may be utilized in the numerical analysis depending on the interpolation field that is selected, and it is generally known that convergence to the proper value will occur considerably more quickly with a good displacement pattern than with a poor pattern, saving computation time. The method for creating finite elements using the strain approach (S.B.A.) is presented in this presentation. When the results are compared with those provided by equivalent displacement-based elements, having the same total number of degrees of freedom, an excellent convergence can be obtained through some application and validation tests using recently developed membrane elements, plate bending elements, and flat shell elements. The effectiveness and performance of the strain-based finite elements in modeling structures are proven by the findings for deflections and stresses.

Keywords: finite elements, plate bending, strain approach, displacement formulation, shell element

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Authors: M. Movahedi Rad

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In this study, a general approach to the reliability based limit analysis of laterally loaded piles is presented. In engineering practice, the uncertainties play a very important role. The aim of this study is to evaluate the lateral load capacity of free head and fixed-head long pile when the plastic limit analysis is considered. In addition to the plastic limit analysis to control the plastic behaviour of the structure, uncertain bound on the complementary strain energy of the residual forces is also applied. This bound has a significant effect for the load parameter. The solution to reliability-based problems is obtained by a computer program which is governed by the reliability index calculation.

Keywords: reliability, laterally loaded pile, residual strain energy, probability, limit analysis

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Authors: Humayun Kabir, Amirul Hasan, Yu Miyaoka, Makiko Yamaguchi, Chisaki Kadota, Kazuaki Takehara

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From field isolates of Newcastle disease virus (NDV) in Japan, one avirulent strain, APMV/northern pintail/Japan/Aomori/2003 (dk-Aomori/03, NDV 261), was selected for its excellent thermostability, and the strain was heat-treated at 56℃ temperatures for 30 min with each passage into Vero cells to maintain thermostability and to adapt Vero cells. After serial 20 passages in Vero cells, it was named NDV Vero20. When growth curves were tested in Vero cells, NDV Vero20 grew well to compare the original NDV261. The HN gene was sequenced, and found motifs that show thermostability. The intracerebral pathogenicity index (ICPI) test score was 0. The thermostability of the virus was confirmed by storing it at different temperatures, including at 37°C. When susceptible chicks were inoculated with NDV Vero20 through eye drops, induced adequate levels of antibody were measured using a serum neutralization test. The results showed that NDV Vero20, a vaccine candidate strain is thermostable, Vero cell adapted, and has immunogenic potential, which would make as an alternative to the traditional embryonated chicken eggs-based vaccine.

Keywords: Newcastle disease virus, thermostability, vaccine, Vero cell adaptability

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Authors: Shiva Emami, Jenny Persson, Bengt Johansson Lindbom

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Group A streptococcus (GAS) is a prevalent human pathogen, causing a wide range of infections and diseases. One of the most well-known virulence factors in GAS is M protein, a surface protein that facilitates bacterial invasion. In this study, we used a recombinant GAS strain (GAS-2W) expressing M protein containing a hyper immunogenic peptide (2W). Mice were immunized three times with heat-killed-GAS subcutaneously at three weeks intervals. Three weeks post last immunization, mice were challenged intraperitoneally with a lethal dose of live GAS. In order to investigate the impact of IFN-ƴ and antibodies in protection against GAS infection, we used a mouse model knock-out for IFN-ƴ (IFN-ƴ KO). We observed immunization with GAS-2W strain can increase protection against GAS infection in mice compared with the original GAS strain. Higher levels of antibodies against M1 protein were measured in GAS-2W-immunized mice. There was also a significant increase in IgG2c response in mice immunized with GAS2W. By using IFN-ƴ KO mice, we showed that not a high level of total IgG, but IgG2c was correlated with protection through the i.p challenge. It also emphasizes the importance of IFN-ƴ cytokine to combat GAS by isotype switching to IgG2c (which is opsonic for phagocytosis). Our data indicate the crucial role of IFN-ƴ in the protective immune response that, together with IgG2c, can induce protection against GAS.

Keywords: Group A streptococcus, IgG2c, IFN-γ, protection

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Authors: Kriangkrai Maneerat, Chutima Prommak

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Indoor wireless localization systems have played an important role to enhance context-aware services. Determining the position of mobile objects in complex indoor environments, such as those in multi-floor buildings, is very challenging problems. This paper presents an effective floor estimation algorithm, which can accurately determine the floor where mobile objects located. The proposed algorithm is based on the confidence interval of the summation of online Received Signal Strength (RSS) obtained from the IEEE 802.15.4 Wireless Sensor Networks (WSN). We compare the performance of the proposed algorithm with those of other floor estimation algorithms in literature by conducting a real implementation of WSN in our facility. The experimental results and analysis showed that the proposed floor estimation algorithm outperformed the other algorithms and provided highest percentage of floor accuracy up to 100% with 95-percent confidence interval.

Keywords: floor estimation algorithm, floor determination, multi-floor building, indoor wireless systems

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Authors: Shifu Hu, Qiong Yu, Wei Xia, Changhong Zhu

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Background: P38α MAPK, which is a member of the canonical MAPK family, is activated in response to various extracellular stresses and plays a role in multiple cellular processes. It is well known that p38α MAPK play vital roles in oocyte maturation, but the localization and functional roles of p38α MAPK during the meiotic maturation of rat oocytes remain unknown. Study Design: In this study, western-blot and immunofluorescent staining were used to investigate the expression and subcellular localization of p38α MAPK during the meiotic maturation of rat oocytes. SB203580, a specific inhibitor of p38α MAPK, was used to study the roles of p38α MAPK in the meiotic cell cycle of rat oocytes. Results: The results found that p38α MAPK phosphorylation (p-p38α MAPK, indicative of p38α MAPK activation) was low at the germinal vesicle (GV) stage, increased 3 h after germinal vesicle breakdown (GVBD), and maintained its maximum at MI (metaphase I) or M II (metaphase II). The p-p38α MAPK mainly accumulated in the germinal vesicle and had no obvious expression in the nucleus. From GVBD to M II, p-p38α MAPK was distributed in the cytoplasm around either the chromosomes or the spindle. We used SB203580, an inhibitor of p38α MAPK, to investigate the possible functional role of p38α MAPK during rat oocyte meiotic maturation. Treatment of GV stage oocytes with 20 μM SB203580 blocked p-p38α MAPK activity, and the spindles appeared abnormal. Additionally, the rate of GVBD after 3h of culture with 20 μM SB203580 (58.8%) was significantly inhibited compared with the control (82.5%, p < 0.05), and the polar body extrusion rate after 12 h of culture with SB203580 was also significantly decreased compared with the control (40.1 vs. 73.3%, p < 0.05). Conclusions: These data indicate that p38α MAPK may play a vital role in rat oocyte meiotic maturation.

Keywords: meiotic maturation, oocyte, p38α MAPK, spindle

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Authors: Surasak Siripornadulsil, Nutt Poomai, Wilailak Siripornadulsil

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Due to a high ethanol demand, the approach for effective ethanol production is important and has been developed rapidly worldwide. Several agricultural wastes are highly abundant in celluloses and the effective cellulose enzymes do exist widely among microorganisms. Accordingly, the cellulose degradation using microbial cellulose to produce a low-cost substrate for ethanol production has attracted more attention. In this study, the cellulose producing bacterial strain has been isolated from rich straw and identified by 16S rDNA sequence analysis as Acinetobacter sp. KKU44. This strain is able to grow and exhibit the cellulose activity. The optimal temperature for its growth and cellulose production is 37 °C. The optimal temperature of bacterial cellulose activity is 60 °C. The cellulose enzyme from Acinetobacter sp. KKU44 is heat-tolerant enzyme. The bacterial culture of 36 h. showed highest cellulose activity at 120 U/mL when grown in LB medium containing 2% (w/v). The capability of Acinetobacter sp. KKU44 to grow in cellulosic agricultural wastes as a sole carbon source and exhibiting the high cellulose activity at high temperature suggested that this strain could be potentially developed further as a cellulose degrading strain for a production of low-cost substrate used in ethanol production.

Keywords: cellulose enzyme, bagasse, rice straw, rice husk, acinetobacter sp. KKU44

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Authors: Bensaid Fatiha

Abstract:

The objective of our present work is the description of the antagonistic capacities of one strain of Pseudomonas fluorescens and the nonpathogenic fungic isolate Fusarium oxysporum against phytopathogenic agent Fusarium oxysporum F. Sp. lycopersici. This work has been achieved in two main parts: the first is interested on the in vitro antagonistic activities; the second was interested to study the soil receptiveness of fusarium wilt tomato. The use of strain of fluorescent Pseudomonas and a non-pathogenic strain of F. oxysporum in the different antagonism tests, has allowed assuring a certain bio-protection from the plants of tomatoes opposite to F. oxysporum F. Sp. lycopersici, agent of a wilt of tomato. These antagonistic have shown a substantial in vitro antagonistic activity on the three mediums (KB, PDA, KB+PDA) against F. oxysporum F. Sp. lycopersici, by inhibiting its growth mycelium with rate of inhibition going until 80 % with non-pathogen of Fusarium oxysporum and 60 % with strain of fluorescens Pseudomonas. Soil microbial balance, between the antagonistic population and that of pathogenic, can be modulated through microbiological variations or abiotic additives influencing directly or indirectly the metabolic behavior microbial. In this experiment, addition of glucose or EDTA, could increase or decrease the resistance of soil by activation of pathogenic or antagonists, as a result of modification and modulation in their metabolic activities.

Keywords: fluorescents, nonpathogenic, fusarium oxysporum, fusarium wilt, antagonism, biological control, soil receptivity

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Authors: A. Baqqal, O. Abduhamid, H. Abdul-Hameed, T. Messager, G. Ayoub

Abstract:

In this contribution, the effect of crystal content on the cyclic response of semi-crystalline polyethylene is studied over a large strain range. Experimental observations on a high-density polyethylene with 72% crystal content and an ultralow density polyethylene with 15% crystal content are reported. The cyclic stretching does appear a thermoplastic-like response for high crystallinity and an elastomeric-like response for low crystallinity, both characterized by a stress-softening, a hysteresis and a residual strain, whose amount depends on the crystallinity and the applied strain. Based on the experimental observations, a unified viscoelastic-viscoplastic constitutive model capturing the polyethylene cyclic response features is proposed. A two-phase representation of the polyethylene microstructure allows taking into consideration the effective contribution of the crystalline and amorphous phases to the intermolecular resistance to deformation which is coupled, to capture the strain hardening, to a resistance to molecular orientation. The polyethylene cyclic response features are captured by introducing evolution laws for the model parameters affected by the microstructure alteration due to the cyclic stretching.

Keywords: cyclic loading unloading, polyethylene, semi-crystalline polymer, viscoelastic-viscoplastic constitutive model

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Authors: Martin Arguelles Perez, Woosoon Yim, Alexander Barzilov

Abstract:

High-fidelity radiation monitoring is an essential component in the enhancement of the situational awareness capabilities of the Department of Energy’s Office of Environmental Management (DOE-EM) personnel. In this paper, multiple units of unmanned aerial vehicles (UAVs) each equipped with a cadmium zinc telluride (CZT) gamma-ray sensor are used for radiation source localization, which can provide vital real-time data for the EM tasks. To achieve this goal, a fully autonomous system of multicopter-based UAV swarm in 3D tetrahedron formation is used for surveying the area of interest and performing radiation source localization. The CZT sensor used in this study is suitable for small-size multicopter UAVs due to its small size and ease of interfacing with the UAV’s onboard electronics for high-resolution gamma spectroscopy enabling the characterization of radiation hazards. The multicopter platform with a fully autonomous flight feature is suitable for low-altitude applications such as radiation contamination sites. The conventional approach uses a single UAV mapping in a predefined waypoint path to predict the relative location and strength of the source, which can be time-consuming for radiation localization tasks. The proposed UAV swarm-based approach can significantly improve its ability to search for and track radiation sources. In this paper, two approaches are developed using (a) 2D planar circular (3 UAVs) and (b) 3D tetrahedron formation (4 UAVs). In both approaches, accurate estimation of the gradient vector is crucial for heading angle calculation. Each UAV carries the CZT sensor; the real-time radiation data are used for the calculation of a bulk heading vector for the swarm to achieve a UAV swarm’s source-seeking behavior. Also, a spinning formation is studied for both cases to improve gradient estimation near a radiation source. In the 3D tetrahedron formation, a UAV located closest to the source is designated as a lead unit to maintain the tetrahedron formation in space. Such a formation demonstrated a collective and coordinated movement for estimating a gradient vector for the radiation source and determining an optimal heading direction of the swarm. The proposed radiation localization technique is studied by computer simulation and validated experimentally in the indoor flight testbed using gamma sources. The technology presented in this paper provides the capability to readily add/replace radiation sensors to the UAV platforms in the field conditions enabling extensive condition measurement and greatly improving situational awareness and event management. Furthermore, the proposed radiation localization approach allows long-term measurements to be efficiently performed at wide areas of interest to prevent disasters and reduce dose risks to people and infrastructure.

Keywords: radiation, unmanned aerial system(UAV), source localization, UAV swarm, tetrahedron formation

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Authors: Jerry John T. M., Sylas V. P., Shijo Joy

Abstract:

Hydrogen is the most essential gas that can be used for many purposes. During the production of hydrogen using raw materials like Soil and leftover cooked rice water (kanjivellam), the major by-product formed is water. Soil is collected from three different places in kottayam district: Kallara, Meenachilar, and Athirampuzha. Collected samples are mixed with rice water and tested for traces of hydrogen using a biohydrogen sensor after 72 hours. The result was the presence of hydrogen in all the 3 samples. After streaking, PCR and gel electrophoresis detected the bacteria which produced the hydrogen. RGCB Thiruvananthapuram conducted the sequencing of the PCR resultant. And identified the bacterial strains. Five variants of Bacillus bacteria ( (1) Bacillus cereus strain JTM GenBank: OP278839.1 (2) Bacillus toyonensis strain JTM2 GenBank: OP278841.1 (3) Bacillus anthracis strain JTM_SR2989-3-R_H08 GenBank: OP278960.1 (4) Bacillus thuringiensis strain JRY1 GenBank: OP278976.1 (5) Bacillus anthracis strain JTM_SR2989-3-F_H07 GenBank: OP278959.1 ) are identified and successfully registered in NCBI Gen bank. These Bacillus bacteria are major types of Rhizobacteria that can form spores and can survive in the soil for a long time period under harsh environmental conditions. Also, plant growth is enhanced by PGPR (Plant growth promoting rhizobacteria) through the induction of systemic resistance, antibiosis, and competitive omission. The molecular sequencing was submitted to the NCBI Gen Bank, and the accession numbers were allotted for the bacterial cultures.

Keywords: bio hydrogen production, bacterial bio hydrogen production, plant related to bacillus bacteria., bacillus bacteria study

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Authors: Hongbo Zhang, Xinlu Tang, Jiangwei Li, Chi Yan

Abstract:

Home zone parking pilot (HPP) is a fast-growing segment in low-speed autonomous driving applications. It requires the car automatically cruise around a parking lot and park itself in a range of up to 100 meters inside a recurrent home/office parking lot, which requires precise parking lot mapping and localization solution. Although Lidar is ideal for SLAM, the car OEMs favor a low-cost fish-eye camera based visual SLAM approach. Recent approaches have employed segmentation models to extract semantic features and improve mapping accuracy, but these AI models are memory unfriendly and computationally expensive, making deploying on embedded ADAS systems difficult. To address this issue, we proposed a new method that utilizes object detection models to extract robust and accurate parking lot features. The proposed method could reduce computational costs while maintaining high accuracy. Once combined with vehicles’ wheel-pulse information, the system could construct maps and locate the vehicle in real-time. This article will discuss in detail (1) the fish-eye based Around View Monitoring (AVM) with transparent chassis images as the inputs, (2) an Object Detection (OD) based feature point extraction algorithm to generate point cloud, (3) a low computational parking lot mapping algorithm and (4) the real-time localization algorithm. At last, we will demonstrate the experiment results with an embedded ADAS system installed on a real car in the underground parking lot.

Keywords: ADAS, home zone parking pilot, object detection, visual SLAM

Procedia PDF Downloads 42