Search results for: reaction wheels modeling

Authors: Geeta Partap, Nitika Chugh

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The present paper deals with the flexural vibrations of homogeneous, isotropic, generalized micropolar microstretch thermoelastic thin Euler-Bernoulli beam resonators, due to Exponential time varying load. Both the axial ends of the beam are assumed to be at simply supported conditions. The governing equations have been solved analytically by using Laplace transforms technique twice with respect to time and space variables respectively. The inversion of Laplace transform in time domain has been performed by using the calculus of residues to obtain deflection.The analytical results have been numerically analyzed with the help of MATLAB software for magnesium like material. The graphical representations and interpretations have been discussed for Deflection of beam under Simply Supported boundary condition and for distinct considered values of time and space as well. The obtained results are easy to implement for engineering analysis and designs of resonators (sensors), modulators, actuators.

Keywords: microstretch, deflection, exponential load, Laplace transforms, residue theorem, simply supported

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Authors: Nicoleta O. Tanase, Ciprian S. Mateescu

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This paper is concerned with the numerical study of the flow through porous media. The purpose of this project is to determine the permeability of a medium and its connection to porosity to be able to identify how the permeability of said medium can be altered without changing the porosity. The numerical simulations are performed in 2D flow configurations with the laminar solvers implemented in Workbench - ANSYS Fluent. The direction of flow of the working fluid (water) is axial, from left to right, and in steady-state conditions. The working fluid is water. The 2D geometry is a channel with 300 mm length and 30 mm width, with a different number of circles that are positioned differently, modelling a porous medium. The permeability of a porous medium can be altered without changing the porosity by positioning the circles differently (by missing the same number of circles) in the flow domain, which induces a change in the flow spectrum. The main goal of the paper is to investigate the flow pattern and permeability under controlled perturbations induced by the variation of velocity and porous medium. Numerical solutions provide insight into all flow magnitudes, one of the most important being the WSS distribution on the circles.

Keywords: CFD, porous media, permeability, flow spectrum

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Authors: Nima Farshidfar, Navid Daryasafar

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In this paper, the seismic stability of reinforced soil slopes is studied using pseudo-dynamic analysis. Equilibrium equations that are applicable to the every kind of failure surface are written using Horizontal Slices Method. In written equations, the balance of the vertical and horizontal forces and moment equilibrium is fully satisfied. Failure surface is assumed to be log-spiral, and non-linear equilibrium equations obtained for the system are solved using Newton-Raphson Method. Earthquake effects are applied as horizontal and vertical pseudo-static coefficients to the problem. To solve this problem, a code was developed in MATLAB, and the critical failure surface is calculated using genetic algorithm. At the end, comparing the results obtained in this paper, effects of various parameters and the effect of using pseudo - dynamic analysis in seismic forces modeling is presented.

Keywords: soil slopes, pseudo-dynamic, genetic algorithm, optimization, limit equilibrium method, log-spiral failure surface

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Authors: Mohammad S. Rouhi, Magdalena Juntikka

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Processing of polymer fiber composites has a remarkable influence on their mechanical performance. These mechanical properties are even more influenced when using recycled reinforcement. Therefore, we place particular attention on the evaluation of micromechanical models to estimate the mechanical properties and compare them against the experimental results of the manufactured composites. For the manufacturing process, an epoxy matrix and carbon fiber production cut-offs as reinforcing material are incorporated using a vacuum infusion process. In addition, continuous textile reinforcement in combination with the epoxy matrix is used as reference material to evaluate the kick-down in mechanical performance of the recycled composite. The experimental results show less degradation of the composite stiffness compared to the strength properties. Observations from the modeling also show the same trend as the error between the theoretical and experimental results is lower for stiffness comparisons than the strength calculations. Yet still, good mechanical performance for specific applications can be expected from these materials.

Keywords: composite recycling, carbon fibers, mechanical properties, micromechanics

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Authors: Seyed Mohamad Rasool Mirkarimi, David Chiaramonti, Samir Bensaid

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Catalytic methane decomposition (CMD, reaction 4) is a one-step process for hydrogen production where carbon in the methane molecule is sequestered in the form of stable and higher-value carbon materials. Metallic catalysts and carbon-based catalysts are two major types of catalysts utilized for the CDM process. Although carbon-based catalysts have lower activity compared to metallic ones, they are less expensive and offer high thermal stability and strong resistance to chemical impurities such as sulfur. Also, it would require less costly separation methods as some of the carbon-based catalysts may not have an active metal component in them. Since the regeneration of metallic catalysts requires burning of the C on their surfaces, which emits CO/CO2, in some cases, using carbon-based catalysts would be recommended because regeneration can be completely avoided, and the catalyst can be directly used in other processes. This work focuses on the effect of biochar as a carbon-based catalyst for the conversion of methane into hydrogen and carbon. Biochar produced from the pyrolysis of poplar wood and activated biochar are used as catalysts for this process. In order to observe the impact of carbon-based catalysts on methane conversion, methane cracking in the absence and presence of catalysts for a gas stream with different levels of methane concentration should be performed. The results of these experiments prove conversion of methane in the absence of catalysts at 900 °C is negligible, whereas in the presence of biochar and activated biochar, significant growth has been observed. Comparing the results of the tests related to using char and activated char shows the enhancement obtained in BET surface area of the catalyst through activation leads to more than 10 vol.% methane conversion.

Keywords: hydrogen production, catalytic methane decomposition, biochar, activated biochar, carbon-based catalyts

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Authors: Pius Babuna

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Sustainable water use is important for the existence of the human race. Water resources carrying capacity (WRCC) measures the sustainability of water use; however, the calculation and optimization of WRCC remain challenging. This study used a mathematical model (the Logistics Growth of Water Resources -LGWR) and a linear objective function to model water sustainability. We tested the validity of the models using data from Ghana. Total freshwater resources, water withdrawal, and population data were used in MATLAB. The results show that the WRCC remains sustainable until the year 2132 ±18, when half of the total annual water resources will be used. The optimized water treatment cost suggests that Ghana currently wastes GHȼ 1115.782± 50 cedis (~$182.21± 50) per water treatment plant per month or ~ 0.67 million gallons of water in an avoidable loss. Adopting an optimized water treatment scheme and a watershed management approach will help sustain the WRCC.

Keywords: water resources carrying capacity, smart water management, optimization, sustainable water use, water withdrawal

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Authors: S. Daqiqeh Rezaei, S. Mohajerzadeh, M. R. Sharifi

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Pedicle screws are used to stabilize vertebrae and treat several types of spinal diseases and injuries. Multiaxial pedicle screws are a type of pedicle screw that increase surgical versatility, but they also increase design complexity. Failure of multiaxial pedicle screws caused by static loading, dynamic loading and fatigue can lead to irreparable damage to the patient. Inappropriate deformation of the multiaxial pedicle screw tulip can cause system failure. Investigation of deformation and stress in these tulips can be employed to optimize multiaxial pedicle screw design. The sensitivity of this matter necessitates precise analyzing and modeling of pedicle screws. In this work, three commercial multiaxial pedicle screw tulips and a newly designed tulip are investigated using finite element analysis. Employing video measuring machine (VMM), tulips are modeled. Afterwards, utilizing ANSYS, static analysis is performed on these models. In the end, stresses and displacements of the models are compared.

Keywords: pedicle screw, multiaxial pedicle screw, finite element analysis, static analysis

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Authors: Abbas Ahmed Albu Shaqraa

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The concept of a safe environment and low greenhouse gas emissions is a common concern especially in the construction industry. The produced carbon dioxide (CO2) emissions are nearly a ton in producing only one ton of Portland cement, which is the primary ingredient of concrete. Current studies had investigated the utilization of several waste materials in producing a cement free concrete. The geopolymer concrete is a green material that results from the reaction of aluminosilicate material with an alkaline liquid. A summary of several recent researches in geopolymer concrete will be presented in this manuscript. In addition, the offered presented review considers the use of several waste materials including fly ash, granulated blast furnace slag, cement kiln dust, kaolin, metakaolin, and limestone powder as binding materials in making geopolymer concrete. Moreover, the mechanical, chemical and thermal properties of geopolymer concrete will be reviewed. In addition, the geopolymer concrete applications and limitations will be discussed as well. The results showed a high early compressive strength gain in geopolymer concrete when dry- heating or steam curing was performed. Also, it was stated that the outstanding acidic resistance of the geopolymer concrete made it possible to be used where the ordinary Portland cement concrete was doubtable. Thus, the commercial geopolymer concrete pipes were favored for sewer system in case of high acidic conditions. Furthermore, it was reported that the geopolymer concrete could stand up to 1200 °C in fire without losing its strength integrity whereas the Portland cement concrete was losing its function upon heating to some 100s °C only. However, the geopolymer concrete still considered as an emerging field and occupied mainly by the precast industries.

Keywords: geopolymer concrete, Portland cement concrete, alkaline liquid, compressive strength

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Authors: Feiying Wu

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Chatbots are computer programs that attempt to engage a human in a dialogue, which originated in the 1960s with MIT's Eliza. However, they have become widespread more recently as advances in language technology have produced chatbots with increasing linguistic quality and sophistication, leading to their potential to serve as a tool for Computer-Assisted Language Learning(CALL). The aim of this article is to assess the feasibility of using two chatbots, Mitsuku and CleverBot, as pedagogical tools for learning English as a second language by stimulating L2 learners with distinct English proficiencies. Speaking of the input of stimulated learners, they are measured by AntWordProfiler to match the user's expected vocabulary proficiency. Totally, there are four chat sessions as each chatbot will converse with both beginners and advanced learners. For evaluation, it focuses on chatbots' responses from a linguistic standpoint, encompassing vocabulary and sentence levels. The vocabulary level is determined by the vocabulary range and the reaction to misspelled words. Grammatical accuracy and responsiveness to poorly formed sentences are assessed for the sentence level. In addition, the assessment of this essay sets 25% lexical and grammatical incorrect input to determine chatbots' corrective ability towards different linguistic forms. Based on statistical evidence and illustration of examples, despite the small sample size, neither Mitsuku nor CleverBot is ideal as educational tools based on their performance through word range, grammatical accuracy, topic range, and corrective feedback for incorrect words and sentences, but rather as a conversational tool for beginners of L2 English.

Keywords: chatbots, CALL, L2, corrective feedback

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Authors: Sara Mohammad Atef Sabaika

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Background: The development of factor VIII (FVIII) inhibitor and hemophilic arthropathy in patients with hemophilia A (PWHA) are a great challenge for hemophilia care. Both genetic and environmental factors led to complications in PWHA. The development of inhibitory antibodies is usually induced by the immune response. Tumor necrosis factor α (TNF-α), one of the cytokines, might contribute to its polymorphism. Aim: Study the association between tumor necrosis alpha level and genotypes in pediatric patients with hemophilia A and its relation to inhibitor development and joint status. Methods: A cross-sectional study was conducted among a sufficient number of PWHA attending the Pediatric Hematology and Oncology Unit, Pediatric department in Menoufia University hospital. The clinical parameters, FVIII, FVIII inhibitor, and serum TNF-α level were assessed. The genotyping of −380G > A TNF-α gene polymorphism was performed using real time polymerase chain reaction. Results: Among the 50 PWHA, 28 (56%) were identified as severe PWHA. The FVIII inhibitor was identified in 6/28 (21.5%) of severe PWHA. There was a significant correlation between serum TNF-α level and the development of inhibitor (p = 0:043). There was significant correlation between polymorphisms of −380G > A TNF-α gene and hemophilic arthropathy development (p = 0:645). Conclusion: The prevalence of FVIII inhibitor in severe PWHA in Menoufia was 21.5%. The frequency of replacement therapy is a risk factor for inhibitor development. Serum TNF-α level and its gene polymorphism might be used to predict inhibitor development and joint status in pediatric patients with hemophilia A.

Keywords: hemophilic arthropathy, TNF alpha., patients witb hemophilia A PWHA, inhibitor

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Authors: Mohamed Shaban, Adel Yahya

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The goal of this paper study is to schedule the power generation units to minimize fuel consumption cost based on a model that solves unit commitment problems. This can be done by utilizing forward dynamic programming method to determine the most economic scheduling of generating units. The model was applied to a power station, which consists of four generating units. The obtained results show that the applications of forward dynamic programming method offer a substantial reduction in fuel consumption cost. The fuel consumption cost has been reduced from $116,326 to $102,181 within a 24-hour period. This means saving about 12.16 % of fuel consumption cost. The study emphasizes the importance of applying modeling schedule programs to the operation of power generation units. As a consequence less consumption of fuel, less loss of power and less pollution

Keywords: unit commitment, forward dynamic, fuel cost, programming, generation scheduling, operation cost, power system, generating units

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Authors: Bhaven N. Tandel, Athira Rajeev

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Sequencing batch reactor process is a suspended growth process operating under non-steady state conditions which utilizes a fill and draw reactor with complete mixing during the batch reaction step (after filling) and where the subsequent steps of aeration and clarification occur in the same tank. All sequencing batch reactor systems have five steps in common, which are carried out in sequence as follows, (1) fill (2) react (3) settle (sedimentation/clarification) (4) draw (decant) and (5) idle. The study was carried out in a sequencing batch reactor of dimensions 44cmx30cmx70cm with a working volume of 40 L. Mechanical stirrer of 100 rpm was used to provide continuous mixing in the react period and oxygen was supplied by fish tank aerators. The duration of a complete cycle of sequencing batch reactor was 8 hours. The cycle period was divided into different phases in sequence as follows-0.25 hours fill phase, 6 hours react period, 1 hour settling phase, 0.5 hours decant period and 0.25 hours idle phase. The study consisted of two runs, run 1 and run 2. Run 1 consisted of 6 hours aerobic react period and run 2 consisted of 3 hours aerobic react period followed by 3 hours anoxic react period. The influent wastewater used for the study had COD, BOD, NH3-N and TKN concentrations of 308.03±48.94 mg/L, 100.36±22.05 mg/L, 14.12±1.18 mg/L, and 24.72±2.21 mg/L respectively. Run 1 had an average COD removal efficiency of 41.28%, BOD removal efficiency of 56.25%, NH3-N removal efficiency of 86.19% and TKN removal efficiency of 54.4%. Run 2 had an average COD removal efficiency of 63.19%, BOD removal efficiency of 73.85%, NH3-N removal efficiency of 90.74% and TKN removal efficiency of 65.25%. It was observed that run 2 gave better performance than run 1 in the removal of COD, BOD and TKN.

Keywords: municipal waste water, aerobic, anoxic, sequencing batch reactor

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Authors: Sarah Devi Silvian, Hanna Shobrina Iqomatul Haq, Fara Cholidatun Nabila, Agustin Krisna Wardani

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Bacteria ability to survive in antibiotic is controlled by the presence of gene that encodes the antibiotic resistance protein. The instability of the antibiotic resistance gene can be observed by exposing the bacteria under the lethal dose of antibiotic. Low concentration of antibiotic can induce mutation, which may take a role in bacterial adaptation through the antibiotic concentration. Lactobacillus casei FNCC 0090 is one of the probiotic bacteria that has an ability to survive in tetracycline by expressing the tetM gene. The aims of this study are to observe the possibilities of mutation happened in L.casei FNCC 0090 by exposing in sub-lethal dose of tetracycline and also observing the instability of the tetM gene by comparing the sequence between the wild type and mutant. L.casei FNCC 0090 has a lethal dose in 60 µg/ml, low concentration is applied to induce the mutation, the range from 10 µg/ml, 15 µg/ml, 30 µg/ml, 45 µg/ml, and 50 µg/ml. L.casei FNCC 0090 is exposed to the low concentration from lowest to the highest concentration to induce the adaptation. Plasmid is isolated from the highest concentration culture which is 50 µg/ml by using modified alkali lysis method with the addition of lysozyme. The tetM gene is isolated by using PCR (Polymerase Chain Reaction) method, then PCR amplicon is purified and sequenced. Sequencing is done on both samples, wild type and mutant. Both sequences are compared and the mutations can be traced in the presence of nucleotides changes. The changing of the nucleotides means that the tetM gene is instable.

Keywords: L. casei FNCC 0090, probiotic, tetM, tetracycline

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Authors: Amina Lyria Deghal Cheridi, Abla Chaker, Ahcene Loubar

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Relap5 system code is one among powerful tools, which is used in the area of design and safety evaluation. This work aims to simulate the behavior of a radiant steam boiler at the steady-state conditions using Relap5 code system. To perform this study, a detailed Relap5 model is built including all the parts of the steam boiler. The control and regulation systems are also considered. To reproduce the most important parameters and phenomena with an acceptable accuracy and fidelity, a strong qualification work is undertaken concerning the facility nodalization. It consists of making a comparison between the code results and the plant available data in steady-state operation mode. Therefore, the model qualification results at the steady-state are in good agreement with the steam boiler experimental data. The steam boiler Relap5 model has proved satisfactory; and the model was capable of predicting the main thermal-hydraulic steady-state conditions of the steam boiler.

Keywords: industrial steam boiler, model qualification, natural circulation, relap5/mod3.2, steady state simulation

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Authors: F. Massri, M. Shkarneh, B. Almassri

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Water scarcity and increasing water demand especially for residential use are major challenges facing Palestine. The need to accurately forecast water consumption is useful for the planning and management of this natural resource. The main objective of this paper is to (i) study the major factors influencing the water consumption in Palestine, (ii) understand the general pattern of Household water consumption, (iii) assess the possible changes in household water consumption and suggest appropriate remedies and (iv) develop prediction model based on the Artificial Neural Network to the water consumption in Palestinian cities. The paper is organized in four parts. The first part includes literature review of household water consumption studies. The second part concerns data collection methodology, conceptual frame work for the household water consumption surveys, survey descriptions and data processing methods. The third part presents descriptive statistics, multiple regression and analysis of the water consumption in the two Palestinian cities. The final part develops the use of Artificial Neural Network for modeling the water consumption in Palestinian cities.

Keywords: water management, demand forecasting, consumption, ANN, Ramallah

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Authors: Jaime Martín-de-Nicolás, David Mata-Moya, Nerea del-Rey-Maestre, Pedro Gómez-del-Hoyo, María-Pilar Jarabo-Amores

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Ship detection is nowadays quite an important issue in tasks related to sea traffic control, fishery management and ship search and rescue. Although it has traditionally been carried out by patrol ships or aircrafts, coverage and weather conditions and sea state can become a problem. Synthetic aperture radars can surpass these coverage limitations and work under any climatological condition. A fast CFAR ship detector based on a robust statistical modeling of sea clutter with respect to sea states in SAR images is used. In this paper, the minimum SNR required to obtain a given detection probability with a given false alarm rate for any sea state is determined. A Gaussian target model using real SAR data is considered. Results show that SNR does not depend heavily on the class considered. Provided there is some variation in the backscattering of targets in SAR imagery, the detection probability is limited and a post-processing stage based on morphology would be suitable.

Keywords: SAR, generalized gamma distribution, detection curves, radar detection

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Authors: Mohammad Reza Ghaani, Niall English

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Hydrogen is looked upon as the next-generation clean-energy carrier; the search for an efficient material and method for storing hydrogen has been, and is, pursued relentlessly. Clathrate hydrates are inclusion compounds wherein guest gas molecules like hydrogen are trapped in a host water-lattice framework. These types of materials can be categorised as potentially attractive hosting environments for physical hydrogen storage (i.e., no chemical reaction upon storage). Non-equilibrium molecular dynamics (NEMD) simulations have been performed to investigate thermal-driven break-up of propane-hydrate interfaces with liquid water at 270-300 K, with the propane hydrate containing either one or no hydrogen molecule in each of its small cavities. In addition, two types of hydrate-surface water-lattice molecular termination were adopted, at the hydrate edge with water: a 001-direct surface cleavage and one with completed cages. The geometric hydrate-ice-liquid distinction criteria of Báez and Clancy were employed to distinguish between the hydrate, ice lattices, and liquid-phase. Consequently, the melting temperatures of interface were estimated, and dissociation rates were observed to be strongly dependent on temperature, with higher dissociation rates at larger over-temperatures vis-à-vis melting. The different hydrate-edge terminations for the hydrate-water interface led to statistically-significant differences in the observed melting point and dissociation profile: it was found that the clathrate with the planar interface melts at around 280 K, whilst the melting temperature of the cage-completed interface was determined to be circa 270 K.

Keywords: hydrogen storage, clathrate hydrate, molecular dynamics, thermal dissociation

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Authors: Easa Ali Abbasi, Akbar Allahverdizadeh, Reza Jahangiri, Behnam Dadashzadeh

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Electrical current measurement is a suitable method for the performance determination of electrical devices. There are two contact and noncontact methods in this measuring process. Contact method has some disadvantages like having direct connection with wire which may endamage the system. Thus, in this paper, a bimorph piezoelectric cantilever beam which has a permanent magnet on its free end is used to measure electrical current in a noncontact way. In mathematical modeling, based on Galerkin method, the governing equation of the cantilever beam is solved, and the equation presenting the relation between applied force and beam’s output voltage is presented. Magnetic force resulting from current carrying wire is considered as the external excitation force of the system. The results are compared with other references in order to demonstrate the accuracy of the mathematical model. Finally, the effects of geometric parameters on the output voltage and natural frequency are presented.

Keywords: cantilever beam, electrical current measurement, forced excitation, piezoelectric

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Authors: Sana Bembli, Nahla Khraief Haddad, Safya Belghith

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This paper deals with a robust model free terminal sliding mode with gravity compensation approach used to control an exoskeleton-upper limb system. The considered system is a 2-DoF robot in interaction with an upper limb used for rehabilitation. The aim of this paper is to control the flexion/extension movement of the shoulder and the elbow joints in presence of matched disturbances. In the first part, we present the exoskeleton-upper limb system modeling. Then, we controlled the considered system by the model free terminal sliding mode with gravity compensation. A stability study is realized. To prove the controller performance, a robustness analysis was needed. Simulation results are provided to confirm the robustness of the gravity compensation combined with to the Model free terminal sliding mode in presence of uncertainties.

Keywords: exoskeleton- upper limb system, model free terminal sliding mode, gravity compensation, robustness analysis

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Authors: W. Nootcharin, S. Sujittra, K. Mayuso, K. Kornphimol, M. Rawiwan

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Silver has distinct antibacterial properties and has been used as a component of commercial products with many applications. An increasing number of commercial products cause risks of silver effects for human and environment such as the symptoms of Argyria and the release of silver to the environment. Therefore, the detection of silver in the aquatic environment is important. The colorimetric chemosensor is designed by the basic of ligand interactions with a metal ion, leading to the change of signals for the naked-eyes which are very useful method to this application. Dithizone ligand is considered as one of the effective chelating reagents for metal ions due to its high selectivity and sensitivity of a photochromic reaction for silver as well as the linear backbone of dithizone affords the rotation of various isomeric forms. The present study is focused on the conformation and interaction of silver ion and silver nanoparticles (AgNPs) with dithizone using density functional theory (DFT). The interaction parameters were determined in term of binding energy of complexes and the geometry optimization, frequency of the structures and calculation of binding energies using density functional approaches B3LYP and the 6-31G(d,p) basis set. Moreover, the interaction of silver–dithizone complexes was supported by UV–Vis spectroscopy, FT-IR spectrum that was simulated by using B3LYP/6-31G(d,p) and 1H NMR spectra calculation using B3LYP/6-311+G(2d,p) method compared with the experimental data. The results showed the ion exchange interaction between hydrogen of dithizone and silver atom, with minimized binding energies of silver–dithizone interaction. However, the result of AgNPs in the form of complexes with dithizone. Moreover, the AgNPs-dithizone complexes were confirmed by using transmission electron microscope (TEM). Therefore, the results can be the useful information for determination of complex interaction using the analysis of computer simulations.

Keywords: silver nanoparticles, dithizone, DFT, NMR

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Authors: Nesrine Benarous, Hassiba Bougueria, Nabila Moussa Slimane, Aouatef Cherouana

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Crystal polymorphism is important for the synthesis of more potent and bioactive pharmaceutical compounds, including their different properties, such as packing arrangement and conformation. In fact, polymorphism plays a vital role in drug development. Different parameters affect the crystallization and give their degree of freedom. Severalproperties affected polymorphism, like kinetics, thermodynamics, spectroscopy, and mechanical property. Various techniques are used for characterizing polymorphs, are crystallography, morphology, phase transitions, molecular motion, and chemical environment. In this work, crystal structures of two polymorphs (I and II) of the Schiff base (SB) title compound were prepared by condensation reaction. The crystal structures of both polymorphs were determined by single X-ray analysis. The two polymorphs crystallize in two different space groups: P21/c for I and Pbca for II. The dihedral angles between the two phenyl rings are 4.81º for I and 82.27º for II. Both crystal structures are built on the basis of moderate and weak hydrogen bonds, 𝜋-stacking, and halogen⋯halogeninteractions. On the other hand, Hirshfeld surface (HS) analysis indicates that the most important contributions to the crystal packing for the two polymorphs are from Cl⋯H/H⋯Cl, H⋯H, and N⋯H/H⋯N contacts. These are followed by C⋯H/H⋯C for compound I and C⋯C and by C⋯H/H⋯C contacts for compound II. Afterwards, the in vitro antibacterial activity revealed that the SB have been found effective against G- bacteria Klebsiella pneumonia andG+ bacteria Staphylococcus aureuswith MIC value of14.37μg/mL. Moreover, the SBexhibited moderate toxicity against Brine Shrimp with LC50 value of 44.19μg/mL.

Keywords: polymorph, crystal structure, hirshfeld surface analysis, in vitro antibacterial activity, toxicity

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Authors: D. Šedivý, S. Fialová

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The main purpose of this study is to show differences between the numerical solution of the flow through the artificial heart valve using Newtonian or non-Newtonian fluid. The simulation was carried out by a commercial computational fluid dynamics (CFD) package based on finite-volume method. An aortic bileaflet heart valve (Sorin Bicarbon) was used as a pattern for model of real heart valve replacement. Computed tomography (CT) was used to gain the accurate parameters of the valve. Data from CT were transferred in the commercial 3D designer, where the model for CFD was made. Carreau rheology model was applied as non-Newtonian fluid. Physiological data of cardiac cycle were used as boundary conditions. Outputs were taken the leaflets excursion from opening to closure and the fluid dynamics through the valve. This study also includes experimental measurement of pressure fields in ambience of valve for verification numerical outputs. Results put in evidence a favorable comparison between the computational solutions of flow through the mechanical heart valve using Newtonian and non-Newtonian fluid.

Keywords: computational modeling, dynamic mesh, mechanical heart valve, non-Newtonian fluid

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Authors: Harshkumar K. Desai, Anuj K. Desai, Jay P. Patel, Snehal V. Trivedi, Yogendrasinh Parmar

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The need of continuous improvement in a product or process in this era of global competition leads to apply value engineering for functional and aesthetic improvement in consideration with economic aspect too. Solar industries located at G.I.D.C., Makarpura, Vadodara, Gujarat, India; a manufacturer of variety of CNC Machines had a challenge to analyze the structural design of column, base, carriage and table of CNC Milling Machine in the account of reduction of overall weight of a machine without affecting the rigidity and accuracy at the time of operation. The identified task is the first attempt to validate and optimize the proposed design of ribbed structure statically using advanced modeling and analysis tools in a systematic way. Results of stress and deformation obtained using analysis software are validated with theoretical analysis and found quite satisfactory. Such optimized results offer a weight reduction of the final assembly which is desired by manufacturers in favor of reduction of material cost, processing cost and handling cost finally.

Keywords: CNC milling machine, optimization, finite element analysis (FEA), weight reduction

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Authors: Zeynep Dikmen, Vural Bütün

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Electron donor or acceptor capability to participate in electron conjugation is the requirement for an electroactive material. Conjugated molecules and polymers bearing heterocyclic units have potential as optically electroactive materials. Thiazolo thiazole based compounds have attention for last two decades, because they have attractive electronic and optical properties, these compounds are useful for electronic application areas such as dye sentisized solar cells (DSSCs), organic light emitting diodes (OLEDs) and field effect transistors (FETs). Thiazolo[5,4-d]thiazole is bicyclic aromatic structure contains N and S atoms which act as electron donor. A new electron accepting or donating group bound to thiazolo [5,4-d] thiazole fused ring can change the electronic, spectroscopic, stability and dyeing properties of the new material. Polyphenylene(thiazolo [5,4-d] thiazole) (p-PhTT) compound was synthesized via condensation reaction of terephthalaldehyde with dithiooxamide. The chemical structure was determined with solid state 13C NMR spectroscopy. Optical properties (i.e. absorbance and band gap) was determined via solid UV-vis spectroscopy. The insoluble polymer was quarternized with 4-vinylbenzyl chloride (VBC). Colorless VBC changed into a yellow liquid. AgNO3 complex were prepared and optical properties were investigated with UV-Vis, fluorescence spectroscopy and X-ray spectroscopy and cyclic voltammetry studies were examined in this research. This structure exhibits good absorbance and fluorescence in UV-vis region. Synthesis scheme of PyTT and preparation of metal complexes are given. PyTT has absorbance at ~360 nm and fluorescence at ~420 nm.

Keywords: thiazolo thiazole, quarternized polymers, polymeric ligands, Ag complexes

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Authors: Somayyeh Naeemi, Ezhar Tamam

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In most of the countries, Facebook allocated high rank of usage among other social network sites. Several studies have examined the effect of Facebook intensity on individuals’ psychological well-being. However, few studies have investigated its effect on eudaimonic well-being. The current study explored how emotional dependency to Facebook relates to psychological well-being in terms of eudaimonic well-being. The number of 402 adolescents 13-16 years old who studied in upper secondary school in Malaysia participated in this study. It was expected to find out a negative association between emotional dependency to Facebook and time spent on Facebook and psychological well-being. It also was examined the moderation effects of self-efficacy on psychological well-being. The results by Structural Equation Modeling revealed that emotional dependency to Facebook has a negative effect on adolescents’ psychological well-being. Surprisingly self-efficacy did not have moderation effect on the relationship between emotional dependency to Facebook and psychological well-being. Lastly, the emotional dependency to Facebook and not the time spent on Facebook lessen adolescents’ psychological well-being, suggesting the value of investigating Facebook usage among college students in future studies.

Keywords: emotional dependency to facebook, psychological well-being, eudaimonic well-being, self-efficacy, adolescent

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Authors: Alex Soares Castro, Matheus Manoel Teles de Menezes, Larissa Silva de Azevedo, Ana Carolina Caleffi Patelli, Osmair Vital de Oliveira, Aline Thais Bruni, Marcelo Firmino de Oliveira

Abstract:

Considering the problem of the seizure of illicit drugs, as well as the development of electrochemical sensors using chemically modified electrodes, this work shows the study of the electrochemical activity of cocaine in carbon paste electrode chemically modified with Cu (II) trans 3-MeO salcn complex. In this context, cyclic voltammetry was performed on 0.1 mol.L⁻¹ KCl supporting electrolyte at a scan speed of 100 mV s⁻¹, using an electrochemical cell composed of three electrodes: Ag /AgCl electrode (filled KCl 3 mol.L⁻¹) from Metrohm® (reference electrode); a platinum spiral electrode, as an auxiliary electrode, and a carbon paste electrode chemically modified with Cu (II) trans 3-MeO complex (as working electrode). Two forms of cocaine were analyzed: cocaine hydrochloride (pH 3) and cocaine free base form (pH 8). The PM7 computational method predicted that the hydrochloride form is more stable than the free base form of cocaine, so with cyclic voltammetry, we found electrochemical signal only for cocaine in the form of hydrochloride, with an anodic peak at 1.10 V, with a linearity range between 2 and 20 μmol L⁻¹ had LD and LQ of 2.39 and 7.26x10-5 mol L⁻¹, respectively. The study also proved that cocaine is adsorbed on the surface of the working electrode, where through an irreversible process, where only anode peaks are observed, we have the oxidation of cocaine, which occurs in the hydrophilic region due to the loss of two electrons. The mechanism of this reaction was confirmed by the ab-inito quantum method.

Keywords: ab-initio computational method, analytical method, cocaine, Schiff base complex, voltammetry

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Authors: Rahul Arora, S. S. Dhami

Abstract:

This paper implements the design structure of industrial robot along with the different transmission components like gear assembly and analysis of complete industrial robot. In this paper, it gives the overview on the most efficient types of modeling and different analysis results that can be obtained for an industrial robot. The investigation is executed in regards to two classifications i.e. the deformation and the stress tests. SolidWorks is utilized to design and review the 3D drawing plan while ANSYS Workbench is utilized to execute the FEA on an industrial robot and the designed component. The CAD evaluation was conducted on a disentangled model of an industrial robot. The study includes design and drafting its transmission system. In CAE study static, modal and dynamic analysis are presented. Every one of the outcomes is divided in regard with the impact of the static and dynamic analysis on the situating exactness of the robot. It gives critical data with respect to parts of the industrial robot that are inclined to harm under higher high force applications. Therefore, the mechanical structure under different operating conditions can help in optimizing the manipulator geometry and in selecting the right material for the same. The FEA analysis is conducted for four different materials on the same industrial robot and gear assembly.

Keywords: CAD, CAE, FEA, robot, static, dynamic, modal, gear assembly

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Authors: Shilpa Kulkarni, Sujata Patrikar

Abstract:

A single-mode fiber directional coupler is modeled and simulated for its application in medical field. Various fiber devices based on evanescent field absorption, interferometry, couplers, resonators, tip coated fibers, etc, have been developed so far, suitable for medical application. This work focuses on the possibility of sensing by single mode fiber directional coupler. In the preset work, a fiber directional coupler is modeled to detect the changes taking place in the surrounding medium optoelectronically. In this work, waveguiding characteristics of the fiber are studied in depth. The sensor is modeled and simulated by finding photocurrent, sensitivity and detection limit by varying various parameters of the directional coupler. The device is optimized for the best possible output. It is found that the directional coupler shows measurable photocurrents and good sensitivity with coupling length in micrometers. It is thus a miniature device, hence, suitable for medical applications.

Keywords: single mode fiber directional coupler, modeling and simulation of fiber directional coupler sensor, biomolecular sensing, medical sensor device

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Authors: Mohammed Kachtali, Imad Fenjiro, Jamal Alkarkouri

Abstract:

Wind erosion is a serious environmental problem in arid and semi-arid regions. Indeed, wind erosion easily removes the finest particles of the soil surface, which also contribute to losing soil fertility. The siltation of infrastructures and cultivated areas and the negative impact on health are additional consequences of wind erosion. In Morocco, wind erosion constitutes the main factor of silting up in coast and Sahara. The aim of our study is to use an equation of wind erosion in order to estimate the soil loses by wind erosion in the coast of Gharb (North of Morocco). The used equation in our model includes the geographic data, climatic data of 30 years and edaphic data collected from area study which contained 11 crossing of 4 stations. Our results have shown that the values of wind erosion are higher and very different between some crossings (p < 0.001). This difference is explained by topography, soil texture, and climate. In conclusion, wind erosion is higher in Gharb coast and varies from station to another; this problem required several methods of control and mitigation.

Keywords: Gharb coast, modeling, silting, wind erosion

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Authors: Minhas Alam, Muhammad Hidayat Rasool, Mohsin Khurshid, Bilal Aslam

Abstract:

Acinetobacter baumannii is a notorious bacterial pathogen that is an emerging nightmare in clinical settings and is mainly involved in severe nosocomial infections. However, the data related to carbapenem-resistant A. baumannii (CRAB) from veterinary settings is limited, especially in developing countries like Pakistan. To investigate the genetic diversity and molecular basis of carbapenem resistance in Acinetobacter baumannii isolates from Cattle, a total of 1960 samples were collected from cattle from Punjab, Pakistan. The isolates were analyzed by routine microbiological procedures and confirmed by polymerase chain reaction (PCR). The isolates were further screened for antimicrobial susceptibility and the presence of multiple antimicrobial-resistant determinants by PCR. Multilocus sequence typing (MLST) was performed. The results of the current study revealed that the overall prevalence of A. baumannii in cattle was 3.28% (65/1980). Among cattle 27.7% (18/65) were found CRAB strains. The CRAB isolates harbor class D β- lactamases genes, e-g, blaOXA-23 and blaOXA-51, 94.4% (17/18). CRAB isolates carry class B β- lactamases gene blaIMP, and only one isolate carries the blaNDM-1 gene. The MLST results of CRAB isolates from cattle demonstrated 5 STs and one new ST. The commonly found sequence types in CRAB isolates were ST2 (n=10, 55.5%), followed by ST642 (n=5, 27.8%) and ST600 & ST889 (n=1, 5.55%). The presence of CRAB isolates in cattle indicates an alarming situation in Punjab, Pakistan. Immediate control measures should be taken to stop the transmission of CRAB isolates within cattle, to the environment, and to clinical settings.

Keywords: acinetobacter baumannii, carbapenemases, veterinary, drug resistance

Procedia PDF Downloads 47