Search results for: fully modified OLS

Authors: Samiya Siddique, Taslima Akter Elma, Shahrina Mahzabin, Tamanna Jerin, Mohammed Russedul Islam

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In the maneuver and designing of highway engineering, pavement performance is a principal concern. Quality of construction and materials, traffic volume, climate, etc. are the factors that affect the performance of asphalt concrete. Modified asphalt requires to attain greater strength and stability even at inimical circumstances. In this point of view, pyrolytic carbon black (PCB), which is a by-product of waste tire pyrolysis, holds incomparable properties that individualizes it from other conventional fillers by making it an imminent modifier of bitumen. Optimum asphalt content of 60/70 penetration grade asphalt is determined 5% through the Marshall Stability and Flow test for the wearing course of flexible pavement. 5, 10, and 15 percentages of PCB are then used with neat asphalt for modification. Deviations of physical and rheological properties are investigated on both PCB modified and neat asphalt by going through several laboratory tests such as penetration, softening point, and ductility tests. The obtained results reveal that the performance of paving asphalt can be upgraded by modifying it with PCB. With the increasing percentage of PCB, ductility is gradually decreased, and also penetration grade is gradually reduced from 60/70 to 30/40. Furthermore, asphalt mixtures modified with PCB demonstrate higher stability and lower flow values. The research discloses that the apposite percentage of PCB used in asphalt concrete plays a significant role in the advancement of pavement performances and reutilizing of waste tires.

Keywords: asphalt modification, pavement performances, pyrolytic carbon black, marshall stability, wearing course

Procedia PDF Downloads 144

Authors: Hamed Khani Arani, Mohammad Shariyat, Armaghan Mohammadian

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In the present study, the free vibration of magnetostrictive nano-plate (MsNP) resting on the Pasternak foundation is investigated. Firstly, the modified couple stress (MCS) and nonlocal elasticity theories are compared together and taken into account to consider the small scale effects; in this paper not only two theories are analyzed but also it improves the MCS theory is more accurate than nonlocal elasticity theory in such problems. A feedback control system is utilized to investigate the effects of a magnetic field. First-order shear deformation theory (FSDT), Hamilton’s principle and energy method are utilized in order to drive the equations of motion and these equations are solved by differential quadrature method (DQM) for simply supported boundary conditions. The MsNP undergoes in-plane forces in x and y directions. In this regard, the dimensionless frequency is plotted to study the effects of small scale parameter, magnetic field, aspect ratio, thickness ratio and compression and tension loads. Results indicate that these parameters play a key role on the natural frequency. According to the above results, MsNP can be used in the communications equipment, smart control vibration of nanostructure especially in sensor and actuators such as wireless linear micro motor and smart nano valves in injectors.

Keywords: feedback control system, magnetostrictive nano-plate, modified couple stress theory, nonlocal elasticity theory, vibration analysis

Procedia PDF Downloads 128

Authors: Preeti Pal, Anjali Pal

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Chitosan is an effective sorbent for removal of contaminants from wastewater. However, the ability of pure chitosan is specific because of its cationic charge. It causes repulsion in the removal process of various cationic charged molecules. The present study has been carried out for the successful removal of Pb²⁺ ions from aqueous solution by modified chitosan beads. Surface modification of chitosan (CS) beads was performed by using the anionic surfactant (AS), sodium dodecyl sulfate (SDS). Micelle aggregation property of SDS has been utilized for the formation of bilayer over the CS beads to produce surfactant modified chitosan (SMCS) beads. Prepared adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) in order to find out their composition and surface morphology. SMCS beads, when compared to the pure CS beads, showed three times higher adsorption. This higher adsorption is believed to be due to the adsolubilization of Pb²⁺ ions on SDS bilayer. This bilayer provides more adsorption sites for quick and effective removal of Pb²⁺ ions from the aqueous phase. Moreover, the kinetic and adsorption isotherm models were employed to the obtained data for the description of the lead adsorption processes. It was found that the removal kinetics follows pseudo-second order model. Adsorption isotherm data fits well to the Langmuir model. The maximum adsorption capacity obtained is 100 mg/g at the dosage of 0.675 g/L for 50 mg/L of Pb²⁺. The adsorption capacity is subject to increase with increasing the Pb²⁺ ions concentration in the solution. The results indicated that the prepared hydrogel beads are efficient adsorbent for removal of Pb²⁺ ions from the aqueous medium.

Keywords: adsolubilisation, anionic surfactant, bilayer, chitosan, Pb²⁺

Procedia PDF Downloads 231

Authors: Mahdieh Farzin Asanjan, Erkan Unal Mumcuoglu

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Mitochondria are cytoplasmic organelles of the cell, which have a significant role in the variety of cellular metabolic functions. Mitochondria act as the power plants of the cell and are surrounded by two membranes. Significant morphological alterations are often due to changes in mitochondrial functions. A powerful technique in order to study the three-dimensional (3D) structure of mitochondria and its alterations in disease states is Electron microscope tomography. Detection of mitochondria in electron microscopy images due to the presence of various subcellular structures and imaging artifacts is a challenging problem. Another challenge is that each image typically contains more than one mitochondrion. Hand segmentation of mitochondria is tedious and time-consuming and also special knowledge about the mitochondria is needed. Fully automatic segmentation methods lead to over-segmentation and mitochondria are not segmented properly. Therefore, semi-automatic segmentation methods with minimum manual effort are required to edit the results of fully automatic segmentation methods. Here two editing tools were implemented by applying spline surface dragging and interactive live-wire segmentation tools. These editing tools were applied separately to the results of fully automatic segmentation. 3D extension of these tools was also studied and tested. Dice coefficients of 2D and 3D for surface dragging using splines were 0.93 and 0.92. This metric for 2D and 3D for live-wire method were 0.94 and 0.91 respectively. The root mean square symmetric surface distance values of 2D and 3D for surface dragging was measured as 0.69, 0.93. The same metrics for live-wire tool were 0.60 and 2.11. Comparing the results of these editing tools with the results of automatic segmentation method, it shows that these editing tools, led to better results and these results were more similar to ground truth image but the required time was higher than hand-segmentation time

Keywords: medical image segmentation, semi-automatic methods, transmission electron microscopy, surface dragging using splines, live-wire

Procedia PDF Downloads 166

Authors: Karine Pimenta Teixeira, Jessica Flores, Isadora PerdigãO Rocha, Leticia De Sá Carneiro, Mahsa Kamali, Ali Ghahremaninezhad

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The advent of nanotechnology has enabled innovative solutions towards improving the behavior of infrastructure materials. Nanomaterials have the potential to revolutionize the construction industry by improving the performance and durability of construction materials, as well as imparting new functionalities to these materials. Due to variability in the environmental temperature during mixing and curing of cementitious materials in practice, it is important to understand how curing temperature influences the behavior of cementitious materials. In addition, high temperature curing is relevant in applications such as oil well cement and precast industry. Knowledge of the influence of temperature on the performance of cementitious materials modified with nanoparticles is important in the nanoengineering of cementitious materials in applications such as oil well cement and precast industry. This presentation aims to investigate the influence of temperature on the hydration, mechanical properties and durability of cementitious materials modified with TiO2 nanoparticles. It was found that temperature improved the early hydration. The cement pastes cured at high temperatures showed an increase in the compressive strength at early age but the strength gain decreased at late ages. The electrical resistivity of the cement pastes cured at high temperatures was shown to decrease more noticeably at late ages compared to that of the room temperature cured cement paste. SEM examination indicated that hydration product was more uniformly distributed in the microstructure of the cement paste cured at room temperature compared to the cement pastes cured at high temperature.

Keywords: cement paste, nanoparticles, temperature, hydration

Procedia PDF Downloads 315

Authors: Cavidan Yakupoglu, Kurt Rohloff

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In this study, we aim to provide a novel parameter selection model for the BFVrns scheme, which is one of the prominent FHE schemes. Parameter selection in lattice-based FHE schemes is a practical challenges for experts or non-experts. Towards a solution to this problem, we introduce a hybrid principles-based approach that combines theoretical with experimental analyses. To begin, we use regression analysis to examine the parameters on the performance and security. The fact that the FHE parameters induce different behaviors on performance, security and Ciphertext Expansion Factor (CEF) that makes the process of parameter selection more challenging. To address this issue, We use a multi-objective optimization algorithm to select the optimum parameter set for performance, CEF and security at the same time. As a result of this optimization, we get an improved parameter set for better performance at a given security level by ensuring correctness and security against lattice attacks by providing at least 128-bit security. Our result enables average ~ 5x smaller CEF and mostly better performance in comparison to the parameter sets given in [1]. This approach can be considered a semiautomated parameter selection. These studies are conducted using the PALISADE homomorphic encryption library, which is a well-known HE library. The abstract goes here.

Keywords: lattice cryptography, fully homomorphic encryption, parameter selection, LWE, RLWE

Procedia PDF Downloads 146

Authors: Redouane Krini, Lutz Nuhn, Hicham El Mard Cheol Woo Ha, Yoondeok Han, Kwang-Sup Lee, Dong-Yol Yang, Jinsoo Joo, Rudolf Zentel

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To use Quantum Dots (QDs) in the two photon initiated polymerization technique (TPIP) for 3D patternings, QDs were modified on the surface with photosensitive end groups which are able to undergo a photopolymerization. We were able to fabricate fluorescent 3D lattice structures using photopatternable QDs by TPIP for photonic devices such as photonic crystals and metamaterials. The QDs in different diameter have different emission colors and through mixing of RGB QDs white light fluorescent from the polymeric structures has been created. Metamaterials are capable for unique interaction with the electrical and magnetic components of the electromagnetic radiation and for manipulating light it is crucial to have a negative refractive index. In combination with QDs via TPIP technique polymeric structures can be designed with properties which cannot be found in nature. This makes these artificial materials gaining a huge importance for real-life applications in photonic and optoelectronic. Understanding of interactions between nanoparticles and biological systems is of a huge interest in the biomedical research field. We developed a synthetic strategy of polymer functionalized nanoparticles for biomedical studies to obtain hybrid systems of QDs and copolymers with a strong binding network in an inner shell and which can be modified in the end through their poly(ethylene glycol) functionalized outer shell. These hybrid systems can be used as models for investigation of cell penetration and drug delivery by using measurements combination between CryoTEM and fluorescence studies.

Keywords: biomedical study models, lithography, photo induced polymerization, quantum dots

Procedia PDF Downloads 519

Authors: JaeYoon Lee, Gi-Hoon Yang, JongHan Ha, MyungGu Yeo, SeungHyun Ahn, Hyeongjin Lee, HoJun Jeon, YongBok Kim, Minseong Kim, GeunHyung Kim

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One of the important factors in tissue engineering is to design optimal biomedical scaffolds, which can be governed by topographical surface characteristics, such as size, shape, and direction. Of these properties, we focused on the effects of nano- to micro-sized hierarchical surface. To fabricate the hierarchical surface structure on poly(ε-caprolactone) (PCL) film, we employed a micro-casting technique by pressing the mold and nano-etching technique using a modified plasma process. The micro-sized topography of PCL film was controlled by sizes of the micro structures on lotus leaf. Also, the nano-sized topography and hydrophilicity of PCL film were controlled by a modified plasma process. After the plasma treatment, the hydrophobic property of the PCL film was significantly changed into hydrophilic property, and the nano-sized structure was well developed. The surface properties of the modified PCL film were investigated in terms of initial cell morphology, attachment, and proliferation using osteoblast-like-cells (MG63). In particular, initial cell attachment, proliferation and osteogenic differentiation in the hierarchical structure were enhanced dramatically compared to those of the smooth surface. We believe that these results are because of a synergistic effect between the hierarchical structure and the reactive functional groups due to the plasma process. Based on the results presented here, we propose a new biomimetic surface model that maybe useful for effectively regenerating hard tissues.

Keywords: hierarchical surface, lotus leaf, nano-etching, plasma treatment

Procedia PDF Downloads 372

Authors: Tatiana Marques Pessanha, Aurora Perez-Gramatges, Regina Sandra Veiga Nascimento

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Emulsions are commonly used in applications involving oil/water dispersions, where handling of interfaces becomes a crucial aspect. The use of emulsion technology has greatly evolved in the last decades to suit the most diverse uses, ranging from cosmetic products and biomedical adjuvants to complex industrial fluids. The stability of these emulsions is influenced by factors such as the amount of oil, size of droplets and emulsifiers used. While commercial surfactants are typically used as emulsifiers to reduce interfacial tension, and therefore increase emulsion stability, these organic amphiphilic compounds are often toxic and expensive. A suitable alternative for emulsifiers can be obtained from the chemical modification of polysaccharides. Our group has been working on modification of polysaccharides to be used as additives in a variety of fluid formulations. In particular, we have obtained promising results using chitosan, a natural and biodegradable polymer that can be easily modified due to the presence of amine groups in its chemical structure. In this way, it is possible to increase both the hydrophobic and hydrophilic character, which renders a water-soluble, amphiphilic polymer that can behave as an emulsifier. The aim of this work was the synthesis of chitosan derivatives structurally modified to act as surfactants in stable oil-in-water. The synthesis of chitosan derivatives occurred in two steps, the first being the hydrophobic modification with the insertion of long hydrocarbon chains, while the second step consisted in the cationization of the amino groups. All products were characterized by infrared spectroscopy (FTIR) and carbon magnetic resonance (13C-NMR) to evaluate the cationization and hydrofobization degrees. These modified polysaccharides were used to formulate oil-in water (O:W) emulsions with different oil/water ratios (i.e 25:75, 35:65, 60:40) using mineral paraffinic oil. The formulations were characterized according to the type of emulsion, density and rheology measurements, as well as emulsion stability at high temperatures. All emulsion formulations were stable for at least 30 days, at room temperature (25°C), and in the case of the high oil content emulsion (60:40), the formulation was also stable at temperatures up to 100°C. Emulsion density was in the range of 0.90-0.87 s.g. The rheological study showed a viscoelastic behaviour in all formulations at room temperature, which is in agreement with the high stability showed by the emulsions, since the polymer acts not only reducing interfacial tension, but also forming an elastic membrane at the oil/water interface that guarantees its integrity. The results obtained in this work are a strong evidence of the possibility of using chemically modified polysaccharides as environmentally friendly alternatives to commercial surfactants in the stabilization of oil-in water formulations.

Keywords: emulsion, polymer, polysaccharide, stability, chemical modification

Procedia PDF Downloads 349

Authors: Kaan Karaoglu, Raif Bayir

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In this study, a cartesian robot is developed to improve the performance and efficiency of wireless charging of electric vehicles. The cartesian robot has three axes, each of which moves linearly. Magnetic positioning is used to align the cartesian robot transmitter charging pad. There are two different wireless charging methods, static and dynamic, for charging electric vehicles. The current state of charge information (SOC State of Charge) and location information are received wirelessly from the electric vehicle. Based on this information, the power to be transmitted is determined, and the transmitter and receiver charging pads are aligned for maximum efficiency. With this study, a fully automated cartesian robot structure will be used to charge electric vehicles with the highest possible efficiency. With the wireless communication established between the electric vehicle and the charging station, the charging status will be monitored in real-time. The cartesian robot developed in this study is a fully automatic system that can be easily used in static wireless charging systems with vehicle-machine communication.

Keywords: electric vehicle, wireless charging systems, energy efficiency, cartesian robot, location detection, trajectory planning

Procedia PDF Downloads 67

Authors: K. G. R. M. Jayathilake, S. Rudra

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Wood degradation in hot compressed water is modeled with a Computational Fluid Dynamics (CFD) code using cellulose, xylan, and lignin as model compounds. Model compounds are reacted under catalyst-free conditions in a temperature range from 250 to 370 °C. Using a simplified reaction scheme where water soluble products, methanol soluble products, char like compounds and gas are generated through intermediates with each model compound. A modified multistage shrinking core model is developed to simulate particle degradation. In the modified shrinking core model, each model compound is hydrolyzed in separate stages. Cellulose is decomposed to glucose/oligomers before producing degradation products. Xylan is decomposed through xylose and then to degradation products where lignin is decomposed into soluble products before producing the total guaiacol, organic carbon (TOC) and then char and gas. Hydrolysis of each model compound is used as the main reaction of the process. Diffusion of water monomers to the particle surface to initiate hydrolysis and dissolution of the products in water is given importance during the modeling process. In the developed model the temperature variation depends on the Arrhenius relationship. Kinetic parameters from the literature are used for the mathematical model. Meanwhile, limited initial fast reaction kinetic data limit the development of more accurate CFD models. Liquefaction results of the CFD model are analyzed and validated using the experimental data available in the literature where it shows reasonable agreement.

Keywords: computational fluid dynamics, liquefaction, shrinking-core, wood

Procedia PDF Downloads 115

Authors: Milad Zoghi, M. Zahangir Kabir

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Performance of armchair graphene nanoribbon (AGNR) resonant tunneling diodes (RTD) alter if they go under strain. This may happen due to either using stretchable substrates or real working conditions such as heat generation. Therefore, it is informative to understand how mechanical deformations such as uniaxial strain can impact the performance of AGNR RTDs. In this paper, two platforms of AGNR RTD consist of width-modified AGNR RTD and electric-field modified AGNR RTD are subjected to both compressive and tensile uniaxial strain ranging from -2% to +2%. It is found that characteristics of AGNR RTD markedly change under both compressive and tensile strain. In particular, peak to valley ratio (PVR) can be totally disappeared upon strong enough strain deformation. Numerical tight binding (TB) coupled with Non-Equilibrium Green's Function (NEGF) is derived for this study to calculate corresponding Hamiltonian matrices and transport properties.

Keywords: armchair graphene nanoribbon, resonant tunneling diode, uniaxial strain, peak to valley ratio

Procedia PDF Downloads 174

Authors: Md. Soebur Rahman, Mahbuba Begum, Raquib Ahsan

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Composite column is a structural member that uses a combination of structural steel shapes, pipes or tubes with or without reinforcing steel bars and reinforced concrete to provide adequate load carrying capacity to sustain either axial compressive loads alone or a combination of axial loads and bending moments. Composite construction takes the advantages of the speed of construction, light weight and strength of steel, and the higher mass, stiffness, damping properties and economy of reinforced concrete. The most usual types of composite columns are the concrete filled steel tubes and the partially or fully encased steel profiles. Fully encased composite column (FEC) provides compressive strength, stability, stiffness, improved fire proofing and better corrosion protection. This paper reports experimental and numerical investigations of the behaviour of concrete encased steel composite columns subjected to short-term axial load. In this study, eleven short FEC columns with square shaped cross section were constructed and tested to examine the load-deflection behavior. The main variables in the test were considered as concrete compressive strength, cross sectional size and percentage of structural steel. A nonlinear 3-D finite element (FE) model has been developed to analyse the inelastic behaviour of steel, concrete, and longitudinal reinforcement as well as the effect of concrete confinement of the FEC columns. FE models have been validated against the current experimental study conduct in the laboratory and published experimental results under concentric load. It has been observed that FE model is able to predict the experimental behaviour of FEC columns under concentric gravity loads with good accuracy. Good agreement has been achieved between the complete experimental and the numerical load-deflection behaviour in this study. The capacities of each constituent of FEC columns such as structural steel, concrete and rebar's were also determined from the numerical study. Concrete is observed to provide around 57% of the total axial capacity of the column whereas the steel I-sections contributes to the rest of the capacity as well as ductility of the overall system. The nonlinear FE model developed in this study is also used to explore the effect of concrete strength and percentage of structural steel on the behaviour of FEC columns under concentric loads. The axial capacity of FEC columns has been found to increase significantly by increasing the strength of concrete.

Keywords: composite, columns, experimental, finite element, fully encased, strength

Procedia PDF Downloads 286

Authors: Sara Kanzi, Izzet Sakalli

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The effect of Lorentz symmetry breaking (LSB) on the Hawking radiation of Schwarzschild-like black hole found in the bumblebee gravity model (SBHBGM) is studied in the framework of quantum gravity. To this end, we consider Hawking radiation spin-0 (bosons) and spin-12particles (fermions), which go in and out through the event horizon of the SBHBGM. We use the modified Klein-Gordon and Dirac equations, which are obtained from the generalized uncertainty principle (GUP) to show how Hawking radiation is affected by the GUP and LSB. In particular, we reveal that independent of the spin of the emitted particles, GUP causes a change in the Hawking temperature of the SBHBGM. Furthermore, we compute the semi-analytic greybody factors (for both bosons and fermions) of the SBHBGM. Thus, we reveal that LSB is effective on the greybody factor of the SBHBGM such that its redundancy decreases the value of the greybody factor. Our findings are graphically depicted.

Keywords: bumblebee gravity model, Hawking radiation, generalized uncertainty principle, Lorentz symmetry breaking

Procedia PDF Downloads 132

Authors: K. A. Chinmaya, M. Udaya Bhaskar

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Multiphase motor drives are now a day considered for numerous applications due to the advantages that they offer when compared to their three-phase counterparts. Proper modeling of inverters and motors are important in devising an appropriate control algorithm. This paper develops a complete modeling of a five-phase inverter and five-phase space vector modulation schemes which can be used for five-phase motor drives. A novel modified algorithm is introduced which enables the sinusoidal output voltages up to certain voltage value. The waveforms of phase to neutral voltage are compared with the different modulation techniques and also different modulation indexes in terms of Low-order Harmonic (LH) voltage of 3rd and 7th present. A detailed performance evolution of existing and newly modified schemes is done in terms of Total Harmonic Distortion (THD).

Keywords: multi-phase drives, space vector modulation, voltage source inverter, low order harmonic voltages, total harmonic distortion

Procedia PDF Downloads 399

Authors: Courtney Evans, Yuto Morimitsu, Tsubasa Hisadome, Futo Inomoto, Masahiro Yoshida, Takayuki Takei

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Hydrogels are useful biomaterials due to their highly biocompatible nature and their ability to absorb large quantities of liquid and mimic soft tissue. They are often used as therapeutic drug delivery systems. However, it is sometimes difficult to sustain controlled release when using hydrophobic medicines, as hydrogels are frequently hydrophilic. As such, this research shows the success of chitosan hydrogels modified through hydrophobic interaction. This was done through the imide bonding of the alkyl groups in fatty aldehydes and the amino groups in chitosan, followed by reductive animation. The resulting cryogels could be optimized for strength as well as sorption and desorption (of a hydrophobic dye used to mimic hydrophobic medicine) by varying the alkyl chain length and the substitution degree of the fatty aldehyde. Optimized cryogels showed potential as biomedical materials, particularly as drug delivery systems.

Keywords: biomedical materials, chitosan, drug carriers, hydrophobic modification

Procedia PDF Downloads 227

Authors: Souad Hassene Daouadji, Larbi Hammadi, Abdelkrim Hazzab

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The slips intended for the manufacture of ceramics must have rheological properties well-defined in order to bring together the qualities required for the casting step (good fluidity for feeding the molds easily settles while generating a regular settling of the dough and for the dehydration phase of the dough in the mold a setting time relatively short is required to have a sufficient refinement which allows demolding both easy and fast). Many additives haveadded in slip of ceramic in order to improve their rheological properties. In this study, we investigated the impact of xanthan gumon rheological properties of ceramic Slip. The modified Cross model is used to fit the stationary flow curves of ceramic slip at different concentration of xanthan added. The thixotropic behavior studied of mixture ceramic slip-xanthan gumat constant temperature is analyzed by using a structural kinetic model (SKM) in order to account for time dependent effect.

Keywords: ceramic slip, xanthan gum, modified cross model, thixotropy, viscosity

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Authors: Jyh Sheen, Yong-Lin Wang

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This research dedicates to find a different measurement procedure of microwave dielectric properties of ceramic materials with high dielectric constants. For the composite of ceramic dispersed in the polymer matrix, the dielectric constants of the composites with different concentrations can be obtained by various mixture equations. The other development of mixture rule is to calculate the permittivity of ceramic from measurements on composite. To do this, the analysis method and theoretical accuracy on six basic mixture laws derived from three basic particle shapes of ceramic fillers have been reported for dielectric constants of ceramic less than 40 at microwave frequency. Similar researches have been done for other well-known mixture rules. They have shown that both the physical curve matching with experimental results and low potential theory error are important to promote the calculation accuracy. Recently, a modified of mixture equation for high dielectric constant ceramics at microwave frequency has also been presented for strontium titanate (SrTiO3) which was selected from five more well known mixing rules and has shown a good accuracy for high dielectric constant measurements. However, it is still not clear the accuracy of this modified equation for other high dielectric constant materials. Therefore, the five more well known mixing rules are selected again to understand their application to other high dielectric constant ceramics. The other high dielectric constant ceramic, TiO2 with dielectric constant 100, was then chosen for this research. Their theoretical error equations are derived. In addition to the theoretical research, experimental measurements are always required. Titanium dioxide is an interesting ceramic for microwave applications. In this research, its powder is adopted as the filler material and polyethylene powder is like the matrix material. The dielectric constants of those ceramic-polyethylene composites with various compositions were measured at 10 GHz. The theoretical curves of the five published mixture equations are shown together with the measured results to understand the curve matching condition of each rule. Finally, based on the experimental observation and theoretical analysis, one of the five rules was selected and modified to a new powder mixture equation. This modified rule has show very good curve matching with the measurement data and low theoretical error. We can then calculate the dielectric constant of pure filler medium (titanium dioxide) by those mixing equations from the measured dielectric constants of composites. The accuracy on the estimating dielectric constant of pure ceramic by various mixture rules will be compared. This modified mixture rule has also shown good measurement accuracy on the dielectric constant of titanium dioxide ceramic. This study can be applied to the microwave dielectric properties measurements of other high dielectric constant ceramic materials in the future.

Keywords: microwave measurement, dielectric constant, mixture rules, composites

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Authors: Xuejiao Shao, Jianguo Chen, Xiaolong Fu

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In this paper, the elastoplastic strain correction factor computed by software of ANSYS was modified, and the fatigue usage factor in air was also corrected considering in water under reactor operating condition. The fatigue of key parts on control rod drive mechanisms was analyzed considering the influence of environmental fatigue caused by the coolant in the react pressure vessel. The elastoplastic strain correction factor was modified by analyzing thermal and mechanical loads separately referring the rules of RCC-M 2002. The new elastoplastic strain correction factor Ke(mix) is computed to replace the original Ke computed by the software of ANSYS when evaluating the fatigue produced by thermal and mechanical loads together. Based on the Ke(mix) and the usage cycle and fatigue design curves, the new range of primary plus secondary stresses was evaluated to obtain the final fatigue usage factor. The results show that the precision of fatigue usage factor can be elevated by using modified Ke when the amplify of the primary and secondary stress is large to some extent. One approach has been proposed for incorporating the environmental effects considering the effects of reactor coolant environments on fatigue life in terms of an environmental correction factor Fen, which is the ratio of fatigue life in air at room. To incorporate environmental effects into the RCCM Code fatigue evaluations, the fatigue usage factor based on the current Code design curves is multiplied by the correction factor. The contribution of environmental effects to results is discussed. Fatigue life decreases logarithmically with decreasing strain rate below 10%/s, which is insensitive to strain rate when temperatures below 100°C.

Keywords: environmental fatigue, usage factor, elastoplastic strain correction factor, environmental correction

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Authors: Jianhong Xiang, Hao Xiang, Linyu Wang

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Compressed sensing (CS) has a wide range of applications in sparse signal reconstruction. Aiming at the problems of low recovery accuracy and long reconstruction time of existing reconstruction algorithms in medical imaging, this paper proposes a corrected smoothing L0 algorithm based on compressed sensing (CSL0). First, an approximate hyperbolic tangent function (AHTF) that is more similar to the L0 norm is proposed to approximate the L0 norm. Secondly, in view of the "sawtooth phenomenon" in the steepest descent method and the problem of sensitivity to the initial value selection in the modified Newton method, the use of the steepest descent method and the modified Newton method are jointly optimized to improve the reconstruction accuracy. Finally, the CSL0 algorithm is simulated on various images. The results show that the algorithm proposed in this paper improves the reconstruction accuracy of the test image by 0-0. 98dB.

Keywords: smoothed L0, compressed sensing, image processing, sparse reconstruction

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Authors: Hilary Limo Rutto

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To better understand the application of diatomite as an adsorbent for the removal of Pb2+ from heavy metal-contaminated water, in this paper, diatomite was used to adsorb Pb2+ from aqueous solution under various conditions. The intrinsic exchange properties were further improved by heating the raw diatomite with fluxing agent at different temperatures and modification with manganese oxides. It is evident that the mass of the adsorbed Pb2+ generally increases after thermal treatment and modification with manganese oxides. The adsorption characteristics of lead on diatomite were studied at pH range of 2.5–12. The favourable pH range was found to be 7.5-8.5. The thermodynamic parameters (i.e.,∆H° ∆G° ∆S°) were evaluated from the temperature dependent adsorption isotherms. The results indicated that the adsorption process of Pb2+ on diatomite was spontaneous, endothermic and physical in nature. The equilibrium data have been analyzed using Langmuir and freundlich isotherm. The Langmuir isotherm was demonstrated to provide the best correlation for the adsorption of lead onto diatomite. The kinetics was studied using Pseudo- first and second-order model on the adsorption of lead onto diatomite. The results give best fit in second-order studies and it can be concluded that the adsorption of lead onto diatomite is second order reaction.

Keywords: thermally modified, diatomite, adsorption, lead

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Authors: Muhammad Safder Shafi, Uzma Javed, Tooba Qasim

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The purpose of this paper is to find out the relationship between training and turnover intention in the presence of mediating variables promotion opportunities and job satisfaction among IT professionals in project based industry. It investigates the relationship directly between 1 independent variable training and dependent variable turnover intention. It also investigates the relationship between independent variable to the mediating variables and mediating variables to the turnover intention. Promotion opportunities and job satisfaction act as a mediator. The study sample comprised of 186 IT professionals from Pakistan, who work on different IT projects. Linear regression and Baron and Kenny approach were used to test the direct and mediated relationship between variables. The survey results demonstrated that job satisfaction fully mediate the relationship between promotion opportunities and turnover intention. Promotion opportunities fully mediate the relationship between employee training and job satisfaction. Promotion opportunities and job satisfaction mediates the relationship between training and turnover intention. The findings from the collected data may help top management to improve organizational strategies to cope up with improving different HR practices like training, pay structure and promotions in order to retain their workforce.

Keywords: HCT, SET, career growth opportunities, job satisfaction, training, turnover intention

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Authors: Ziba Talaeizadeh, Taghi Ebadi

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Hospitals and medical centers generate a wide array of infectious waste on a daily basis, leading to pressing environmental concerns associated with proper disposal. Disposable plastic items and spun-bond clothing, commonly made from polypropylene, pose a significant risk of disease transmission, necessitating specialized waste management strategies. Incorporating these materials into bituminous asphalt production offers a potential solution, as it can modify asphalt mixtures and reduce susceptibility to cracking. This study aims to assess the crack resistance of asphalt mixtures modified with hospital spun-bond waste. Asphalt mixtures were prepared using the Marshall method, with spun-bond waste added in varying proportions (5% to 20%). The Semi-Circular Bending (SCB) test was conducted to evaluate asphalt fracture behavior under Mode I loading at controlled speeds of 5, 20, and 50 millimeters per minute and an average temperature of 25°C. Parameters such as fracture energy (FE) and Crack Resistance Index (CRI) were quantified. The results indicate that the addition of 10% to 15% spun-bond polypropylene polymer enhances the performance of the modified mixture, resulting in an 18% increase in fracture energy and an 11% reduction in cracking stiffness compared to the control sample. Further investigations involving factors like compaction level, bitumen type, and aggregate grading are recommended to address medical waste management and mitigate asphalt pavement cracking issues.

Keywords: asphalt cracking, hospital waste, semi-circular bending test, spun-bond

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Authors: Aydin Teymourifar, Gurkan Ozturk, Ozan Bahadir

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NSGA-II is one of the most well-known and most widely used evolutionary algorithms. In addition to its new versions, such as NSGA-III, there are several modified types of this algorithm in the literature. In this paper, a hybrid NSGA-II algorithm has been suggested for solving the multi-objective flexible job shop scheduling problem. For a better search, new neighborhood-based crossover and mutation operators are defined. To create new generations, the neighbors of the selected individuals by the tournament selection are constructed. Also, at the end of each iteration, before sorting, neighbors of a certain number of good solutions are derived, except for solutions protected by elitism. The neighbors are generated using a constraint-based neural network that uses various constructs. The non-dominated sorting and crowding distance operators are same as the classic NSGA-II. A comparison based on some multi-objective benchmarks from the literature shows the efficiency of the algorithm.

Keywords: flexible job shop scheduling problem, multi-objective optimization, NSGA-II algorithm, neighborhood structures

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Authors: Tachita Vlad-Bubulac, Ionela-Daniela Carja, Diana Serbezeanu, Corneliu Hamciuc, Vicente Javier Forrat Perez

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The present work describes the preparation of new organophosphorus compounds with high content of phosphorus followed by the incorporation of these compounds into epoxy resin systems in order to investigate the phosphorus effect in terms of thermal stability, flame-retardant and mechanical properties of modified epoxy resins. Thus, two new organophosphorus compounds have been synthesized and fully characterized. 6-Oxido-6H-dibenz[c,e][1,2]oxaphosphorinyl-phenylcarbinol has been prepared by the addition reaction of P–H group of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to carbonyl group of benzaldehyde. By treating the phenylcarbinol derivative with POCl3 a new phosphorus compound was obtained, having a content of 12.227% P. The organophosphorus compounds have been purified by recrystallization while their chemical structures have been confirmed by melting point measurements, FTIR and HNMR spectroscopies. In the next step various flame-retardant epoxy resins with different content of phosphorus have been prepared starting from a commercial epoxy resin and using dicyandiamide (DICY) as a latent curing agent in the presence of an accelerator. Differential scanning calorimetry (DSC) has been applied to investigate the behavior and kinetics of curing process of thermosetting systems. The results showed that the best curing characteristic and glass transition temperature are obtained at a ratio of epoxy resin: DICY: accelerator equal to 94:5:1. The thermal stability of the phosphorus-containing epoxy resins was investigated by thermogravimetric analysis in nitrogen and air, DSC, SEM and LOI test measurements.

Keywords: epoxy resins, flame retardant properties, phosphorus-containing compounds, thermal stability

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Authors: Maher Aburrous, Adel Khelifi, Manar Abu Talib

Abstract:

Transactions performed by financial institutions on daily basis require XML encryption on large scale. Encrypting large volume of message fully will result both performance and resource issues. In this paper a novel approach is presented for securing financial XML transactions using classification data mining (DM) algorithms. Our strategy defines the complete process of classifying XML transactions by using set of classification algorithms, classified XML documents processed at later stage using element-wise encryption. Classification algorithms were used to identify the XML transaction rules and factors in order to classify the message content fetching important elements within. We have implemented four classification algorithms to fetch the importance level value within each XML document. Classified content is processed using element-wise encryption for selected parts with "High", "Medium" or “Low” importance level values. Element-wise encryption is performed using AES symmetric encryption algorithm and proposed modified algorithm for AES to overcome the problem of computational overhead, in which substitute byte, shift row will remain as in the original AES while mix column operation is replaced by 128 permutation operation followed by add round key operation. An implementation has been conducted using data set fetched from e-banking service to present system functionality and efficiency. Results from our implementation showed a clear improvement in processing time encrypting XML documents.

Keywords: XML transaction, encryption, Advanced Encryption Standard (AES), XML classification, e-banking security, fuzzy classification, cryptography, intelligent encryption

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Authors: Habib Shaban

Abstract:

Nanocomposites of isotactic polypropylene (iPP) and date wood fiber were prepared after modification of the host matrix by reactive extrusion grafting of maleic anhydride. Chemical and mechanical treatment of date wood flour (WF) was conducted to obtain nanocrystalline cellulose. Layered silicates (clay) were partially intercalated with date wood fiber, and the modified layered silicate was used as filler in the PP matrix via a melt-blending process. The tensile strength of composites prepared from wood fiber modified clay was greater than that of the iPP-clay and iPP-WF composites at a 6% filler concentration, whereas deterioration of mechanical properties was observed when clay and WF were used alone for reinforcement. The dispersion of the filler in the matrix significantly decreased after clay modification with cellulose at higher concentrations, as shown by X-ray diffraction (XRD) data.

Keywords: nanocomposites, isotactic polypropylene, date wood flour, intercalated, melt-blending

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Authors: Josef Sepitka, Petr Vlcak, Tomas Horazdovsky, Vratislav Perina

Abstract:

An ion implantation technique was used for designing the surface area of a titanium alloy and for irradiation-enhanced hardening of the surface. The Ti6Al4V alloy was treated by nitrogen ion implantation at fluences of 2·10¹⁷ and 4·10¹⁷ cm^-2 and at ion energy 90 keV. The depth distribution of the nitrogen was investigated by Rutherford Backscattering Spectroscopy. The gradient of mechanical properties was investigated by nanoindentation. The continuous measurement mode was used to obtain depth profiles of the indentation hardness and the reduced storage modulus of the modified surface area. The reduced storage modulus and the hardness increase with increasing fluence. Increased fluence shifts the peak of the mechanical properties as well as the peak of nitrogen concentration towards to the surface. This effect suggests a direct relationship between mechanical properties and nitrogen distribution.

Keywords: nitrogen ion implantation, titanium-based nanolayer, storage modulus, hardness, microstructure

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Authors: Taekyong Lee, Joon-Young Kim, Jae-Min Cha

Abstract:

Piping and instrumentation diagram (P&ID) is an essential design drawing describing the interconnection of process equipment and the instrumentation installed to control the process. P&IDs are modified and managed throughout a whole life cycle of a process plant. For the ease of data transfer, P&IDs are generally handed over from a design company to an engineering company as portable document format (PDF) which is hard to be modified. Therefore, engineering companies have to deploy a great deal of time and human resources only for manually converting P&ID images into a computer aided design (CAD) file format. To reduce the inefficiency of the P&ID conversion, various symbols and texts in P&ID images should be automatically recognized. However, recognizing information in P&ID images is not an easy task. A P&ID image usually contains hundreds of symbol and text objects. Most objects are pretty small compared to the size of a whole image and are densely packed together. Traditional recognition methods based on geometrical features are not capable enough to recognize every elements of a P&ID image. To overcome these difficulties, state-of-the-art deep learning models, RetinaNet and connectionist text proposal network (CTPN) were used to build a system for recognizing symbols and texts in a P&ID image. Using the RetinaNet and the CTPN model carefully modified and tuned for P&ID image dataset, the developed system recognizes texts, equipment symbols, piping symbols and instrumentation symbols from an input P&ID image and save the recognition results as the pre-defined extensible markup language format. In the test using a commercial P&ID image, the P&ID information recognition system correctly recognized 97% of the symbols and 81.4% of the texts.

Keywords: object recognition system, P&ID, symbol recognition, text recognition

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Authors: Hossein Aghababaei, Sergio Vitale, Giampaolo Ferraioli

Abstract:

In the context of Synthetic Aperture Radar (SAR) data, polarization is an important source of information for Earth's surface monitoring. SAR Systems are often considered to transmit only one polarization. This constraint leads to either single or dual polarimetric SAR imaging modalities. Single polarimetric systems operate with a fixed single polarization of both transmitted and received electromagnetic (EM) waves, resulting in a single acquisition channel. Dual polarimetric systems, on the other hand, transmit in one fixed polarization and receive in two orthogonal polarizations, resulting in two acquisition channels. Dual polarimetric systems are obviously more informative than single polarimetric systems and are increasingly being used for a variety of remote sensing applications. In dual polarimetric systems, the choice of polarizations for the transmitter and the receiver is open. The choice of circular transmit polarization and coherent dual linear receive polarizations forms a special dual polarimetric system called hybrid polarimetry, which brings the properties of rotational invariance to geometrical orientations of features in the scene and optimizes the design of the radar in terms of reliability, mass, and power constraints. The complete characterization of target scattering, however, requires fully polarimetric data, which can be acquired with systems that transmit two orthogonal polarizations. This adds further complexity to data acquisition and shortens the coverage area or swath of fully polarimetric images compared to the swath of dual or hybrid polarimetric images. The search for solutions to augment dual polarimetric data to full polarimetric data will therefore take advantage of full characterization and exploitation of the backscattered field over a wider coverage with less system complexity. Several methods for reconstructing fully polarimetric images using hybrid polarimetric data can be found in the literature. Although the improvements achieved by the newly investigated and experimented reconstruction techniques are undeniable, the existing methods are, however, mostly based upon model assumptions (especially the assumption of reflectance symmetry), which may limit their reliability and applicability to vegetation and forest scenarios. To overcome the problems of these techniques, this paper proposes a new framework for reconstructing fully polarimetric information from hybrid polarimetric data. The framework uses Deep Learning solutions to augment hybrid polarimetric data without relying on model assumptions. A convolutional neural network (CNN) with a specific architecture and loss function is defined for this augmentation problem by focusing on different scattering properties of the polarimetric data. In particular, the method controls the CNN training process with respect to several characteristic features of polarimetric images defined by the combination of different terms in the cost or loss function. The proposed method is experimentally validated with real data sets and compared with a well-known and standard approach from the literature. From the experiments, the reconstruction performance of the proposed framework is superior to conventional reconstruction methods. The pseudo fully polarimetric data reconstructed by the proposed method also agree well with the actual fully polarimetric images acquired by radar systems, confirming the reliability and efficiency of the proposed method.

Keywords: SAR image, polarimetric SAR image, convolutional neural network, deep learnig, deep neural network

Procedia PDF Downloads 65