Search results for: lifshitz formula

Authors: Mahesh Koti

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In this paper, we present a quantum transport study of a quantum dot in steady state in the presence of static gate potential. We consider a quantum dot coupled to the two metallic leads. The quantum dot under study is modeled through Anderson Impurity Model (AIM) with hopping parameter modulated through voltage drop between leads and the central dot region. Based on the Landauer's formula derived from Nonequilibrium Green's Function and Single Electron Theory, the essential ingredients of transport properties are revealed. We show that the results out of two approaches closely agree with each other. We demonstrate that Landauer current response derived from single electron approach converges with non-zero interaction through gate potential whereas Landauer current response derived from Nonequilibrium Green's Function (NEGF) hits a pole.

Keywords: Anderson impurity model (AIM), nonequilibrium Green's function (NEGF), Landauer's formula, single electron analysis

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Authors: Li Yin, Xiaoqin Wang

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Background and purpose: Cancer diagnosis is part of a complex stochastic process, in which patients' personal and social characteristics influence the choice of diagnosing methods, diagnosing methods, in turn, influence the initial assessment of cancer stage, the initial assessment, in turn, influences the choice of treating methods, and treating methods in turn influence cancer outcomes such as cancer survival. To evaluate diagnosing methods, one needs to estimate and test the causal effect of a regime of cancer diagnosis and treatments. Recently, Wang and Yin (Annals of statistics, 2020) derived a new general formula, which expresses these causal effects in terms of the point effects of treatments in single-point causal inference. As a result, it is possible to estimate and test these causal effects via point effects. The purpose of the work is to estimate and test causal effects under various regimes of cancer diagnosis and treatments via point effects. Challenges and solutions: The cancer stage has influences from earlier diagnosis as well as on subsequent treatments. As a consequence, it is highly difficult to estimate and test the causal effects via standard parameters, that is, the conditional survival given all stationary covariates, diagnosing methods, cancer stage and prognosis factors, treating methods. Instead of standard parameters, we use the point effects of cancer diagnosis and treatments to estimate and test causal effects under various regimes of cancer diagnosis and treatments. We are able to use familiar methods in the framework of single-point causal inference to accomplish the task. Achievements: we have applied this method to stomach cancer survival from a clinical study in Sweden. We have studied causal effects under various regimes, including the optimal regime of diagnosis and treatments and the effect moderation of the causal effect by age and gender.

Keywords: cancer diagnosis, causal effect, point effect, G-formula, sequential causal effect

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Authors: Jessyca A. Bessa, Darlan A. Barroso, Jonas P. Reges, Auzuir R. Alexandria

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This work aims to study the rocker. This is a device of the suspension of Formula SAE vehicle that receives efforts from the motion scrolling of the vehicle and transmits them to the chassis frame minimized by a momentum ratio and smoothed by the set spring - damper. A review of parameters used in vehicle dynamics and a geometric analysis of the forces and stresses caused by such was carried out. The main function of the rocker is to reduce the force transmitted to the frame due to movement of rolling and subsequent application of the suspension. This functions is taken as satisfactory, since the force applied to the wheel and which would be transmitted to the chassis is reduced from 3833.9N to 3496.48N. From these values can be further more detailed simulations using the finite element method aimed at mass reduction or even rocker manufacturing feasibility aluminum. Then, the analysis by the finite element method was applied. This analysis uses the theory of discretization of systems and examines the strength of the component based on the distortion energy, determining the maximum straining experienced by the component and the region of higher demand.

Keywords: rocker, suspension, the finite element method, mechatronics engineering

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Authors: Sergei P. Efimov

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The anomalous magnetic moment of the electron is calculated by introducing the effective mass of the virtual part of the electron structure. In this case, the anomalous moment is inversely proportional to the effective mass Meff, which is shown to be a linear combination of the neutron, proton, and electrostatic electron field masses. The spin of a rotating structure is assumed to be equal to 3/2, while the spin of a 'bare' electron is equal to unity, the resultant spin being 1/2. A simple analysis gives the coefficients for a linear combination of proton and electron masses, the approximation precision giving here nine significant digits after the decimal point. The summand proportional to α² adds four more digits. Thus, the conception of the effective mass Meff leads to the formula for the total magnetic moment of the electron, which is accurate to fourteen digits. Association with the virtual beta-decay reaction and possible reasons for simplicity of the derived formula are discussed.

Keywords: anomalous magnetic moment of electron, comparison with quantum electrodynamics. effective mass, fifteen significant figures, proton and neutron masses

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Authors: Erik Vassøy Olsen, Hirpa G. Lemu

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Inspired by the Formula-1 competition, IMechE (Institute of Mechanical Engineers) and Formula SAE (Society of Mechanical Engineers) organize annual competitions for University and College students worldwide to compete with a single-seat race car they have designed and built. The design of the chassis or the frame is a key component of the competition because the weight and stiffness properties are directly related with the performance of the car and the safety of the driver. In addition, a reduced weight of the chassis has a direct influence on the design of other components in the car. Among others, it improves the power to weight ratio and the aerodynamic performance. As the power output of the engine or the battery installed in the car is limited to 80 kW, increasing the power to weight ratio demands reduction of the weight of the chassis, which represents the major part of the weight of the car. In order to reduce the weight of the car, ION Racing team from the University of Stavanger, Norway, opted for a monocoque design. To ensure fulfilment of the above-mentioned requirements of the chassis, the monocoque design should provide sufficient torsional stiffness and absorb the impact energy in case of a possible collision. The study reported in this article is based on the requirements for Formula Student competition. As part of this study, diverse mechanical tests were conducted to determine the mechanical properties and performances of the monocoque design. Upon a comprehensive theoretical study of the mechanical properties of sandwich composite materials and the requirements of monocoque design in the competition rules, diverse tests were conducted including 3-point bending test, perimeter shear test and test for absorbed energy. The test panels were homemade and prepared with an equivalent size of the side impact zone of the monocoque, i.e. 275 mm x 500 mm so that the obtained results from the tests can be representative. Different layups of the test panels with identical core material and the same number of layers of carbon fibre were tested and compared. Influence of the core material thickness was also studied. Furthermore, analytical calculations and numerical analysis were conducted to check compliance to the stated rules for Structural Equivalency with steel grade SAE/AISI 1010. The test results were also compared with calculated results with respect to bending and torsional stiffness, energy absorption, buckling, etc. The obtained results demonstrate that the material composition and strength of the composite material selected for the monocoque design has equivalent structural properties as a welded frame and thus comply with the competition requirements. The developed analytical calculation algorithms and relations will be useful for future monocoque designs with different lay-ups and compositions.

Keywords: composite material, Formula student, ION racing, monocoque design, structural equivalence

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Authors: Jorge Gonzalez Camus, Valentin Keyantuo, Mahamadi Warma

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In this work, we obtain representation results for solutions of a time-fractional differential equation involving the discrete fractional Laplace operator in terms of generalized Wright functions. Such equations arise in the modeling of many physical systems, for example, chain processes in chemistry and radioactivity. The focus is on the linear problem of the simplified Moore - Gibson - Thompson equation, where the discrete fractional Laplacian and the Caputo fractional derivate of order on (0,2] are involved. As a particular case, we obtain the explicit solution for the discrete heat equation and discrete wave equation. Furthermore, we show the explicit solution for the equation involving the perturbed Laplacian by the identity operator. The main tool for obtaining the explicit solution are the Laplace and discrete Fourier transforms, and Stirling's formula. The methodology mainly is to apply both transforms in the equation, to find the inverse of each transform, and to prove that this solution is well defined, using Stirling´s formula.

Keywords: discrete fractional Laplacian, explicit representation of solutions, fractional heat and wave equations, fundamental

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Authors: T. J. Stepien, L. T. Stepien

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This abstract concerns an extremely fundamental issue. Namely, the fundamental problem of science is the issue of consistency. In this abstract, we present the theorem saying that the classical calculus of quantifiers is inconsistent in the traditional sense. At the beginning, we introduce a notation, and later we remind the definition of the consistency in the traditional sense. S1 is the set of all well-formed formulas in the calculus of quantifiers. RS1 denotes the set of all rules over the set S1. Cn(R, X) is the set of all formulas standardly provable from X by rules R, where R is a subset of RS1, and X is a subset of S1. The couple < R,X > is called a system, whenever R is a subset of RS1, and X is a subset of S1. Definition: The system < R,X > is consistent in the traditional sense if there does not exist any formula from the set S1, such that this formula and its negation are provable from X, by using rules from R. Finally, < R0+, L2 > denotes the classical calculus of quantifiers, where R0+ consists of Modus Ponens and the generalization rule. L2 is the set of all formulas valid in the classical calculus of quantifiers. The Main Result: The system < R0+, L2 > is inconsistent in the traditional sense.

Keywords: classical calculus of quantifiers, classical predicate calculus, generalization rule, consistency in the traditional sense, Modus Ponens

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Authors: Sumachaya Harnsukworapanich, Tetsuo Ichimori

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The apportionment method is used by many countries, to calculate the distribution of seats in political bodies. For example, this method is used in the United States (U.S.) to distribute house seats proportionally based on the population of the electoral district. Famous apportionment methods include the divisor methods called the Adams Method, Dean Method, Hill Method, Jefferson Method and Webster Method. Sometimes the results from the implementation of these divisor methods are unfair and include errors. Therefore, it is important to examine the optimization of this method by using a bias measurement to figure out precise and fair results. In this research we investigate the bias of divisor methods in the U.S. Houses of Representatives toward large and small states by applying the Stolarsky Mean Method. We compare the bias of the apportionment method by using two famous bias measurements: The Balinski and Young measurement and the Ernst measurement. Both measurements have a formula for large and small states. The Third measurement however, which was created by the researchers, did not factor in the element of large and small states into the formula. All three measurements are compared and the results show that our measurement produces similar results to the other two famous measurements.

Keywords: apportionment, bias, divisor, fair, measurement

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Authors: Nopadol Nimsuwan, Sumet Prom-in

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The purpose of this study was to investigate the body types, size, and body compositions of softball players in the 39th National Games of Thailand. The population of this study was 352 softball players who participated in the 39th National Games of Thailand from which a sample size of 291 was determined using the Taro Yamane formula and selection is made with stratified sampling method. The data collected were weight, height, arm length, leg length, chest circumference, mid-upper arm circumference, calf circumference, subcutaneous fat in the upper arm area, the scapula bone area, above the pelvis area, and mid-calf area. Keys and Brozek formula was used to calculate the fat quantity, Kitagawa formula to calculate the muscle quantity, and Heath and Carter method was used to determine the values of body dimensions. The results of the study can be concluded as follows. The average body dimensions of the male softball players were the endo-mesomorph body type while the average body dimensions of female softball players were the meso-endomorph body type. When considered according to the softball positions, it was found that the male softball players in every position had the endo-mesomorph body type while the female softball players in every position had the meso-endomorph body type except for the center fielder that had the endo-ectomorph body type. The endo-mesomorph body type is suitable for male softball players, and the meso-endomorph body type is suitable for female softball players because these body types are suitable for the five basic softball skills which are: gripping, throwing, catching, hitting, and base running. Thus, people related to selecting softball players to play in sports competitions of different levels should consider factors in terms of body type, size, and body components of the players.

Keywords: body types, softball players, national games of Thailand, social sustainability

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Authors: Yuan Yan Tang, Lina Yang, Hong Li

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Harmonic model is a very important approximation for the image transform. The harmanic model converts an image into arbitrary shape; however, this mode cannot be described by any fixed functions in mathematics. In fact, it is represented by partial differential equation (PDE) with boundary conditions. Therefore, to develop an efficient method to solve such a PDE is extremely significant in the image transform. In this paper, a novel Integral Equation-Wavelet based method is presented, which consists of three steps: (1) The partial differential equation is converted into boundary integral equation and representation by an indirect method. (2) The boundary integral equation and representation are changed to plane integral equation and representation by boundary measure formula. (3) The plane integral equation and representation are then solved by a method we call wavelet collocation. Our approach has two main advantages, the shape of an image is arbitrary and the program code is independent of the boundary. The performance of our method is evaluated by numerical experiments.

Keywords: harmonic model, partial differential equation (PDE), integral equation, integral representation, boundary measure formula, wavelet collocation

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Authors: Yazid Alkraimeen

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Precise prediction of dielectric stresses and high voltages of power transformers require the accurate calculation of frequency-dependent parameters. A lack of accuracy can result in severe damages to transformer windings. Transient conditions is stuided by digital computers, which require the implementation of accurate models. This paper analyzes the computation of frequency-dependent skin and proximity losses included in the transformer winding model, using analytical equations and Finite Element Method (FEM). A modified formula to calculate the proximity and the skin losses is presented. The results of the frequency-dependent parameter calculations are verified using the Finite Element Method. The time-domain transient voltages are obtained using Numerical Inverse Laplace Transform. The results show that the classical formula for proximity losses is overestimating the transient voltages when compared with the results obtained from the modified method on a simple transformer geometry.

Keywords: fast front transients, proximity losses, transformer winding modeling, skin losses

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Authors: Mohsen Farahat, Tsuyoshi Hirajima

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Surface characteristics of Bacillus megaterium strain were investigated; zeta potential, FTIR and contact angle were measured. Surface energy components including Lifshitz-van der Waals, Hamaker constant, and acid/base components (Lewis acid/Lewis base) were calculated from the contact angle data. The results showed that the microbial cells were negatively charged over all pH regions with high values at alkaline region. A hydrophilic nature for the strain was confirmed by contact angle and free energy of adhesion between microbial cells. Adsorption affinity of the strain toward dolomite was studied at different pH values. The results showed that the cells had a high affinity to dolomite at acid pH comparing to neutral and alkaline pH. Extended DLVO theory was applied to calculate interaction energy between B. megaterium cells and dolomite particles. The adsorption results were in agreement with the results of Extended DLVO approach. Surface changes occurred on dolomite surface after the bio-treatment were monitored; contact angle decreased from 69° to 38° and the mineral’s floatability decreased from 95% to 25% after the treatment.

Keywords: Bacillus megaterium, surface modification, flotation, dolomite, adhesion energy

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Authors: Rashmi Shahu

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Flexibility is becoming a more widely accepted aspect of project management. Although contingency theory in project management states that the unknowns are controllable, complexity theory believes that the best way to handle the unknowns would be to have a flexible approach rather than rigidity. Designing a flexible system is a method of managing uncertainty. The present research work aims to evaluate flexibility in the initial design phase of projects taking examples of construction projects. Flexibility in the initial design phase is modeled in order to know the advantage in future. The comparison between the extra cost of flexibility in the initial design phase and the discount that can be achieved in future due to this premium will help the developers in making strategic decisions. This research uses a methodology for valuing flexibility by developing a mathematical formula for predicting future saving of cost. Two case studies were considered in this research to validate the mathematical formula. This research explains three case studies of an educational institution 28 years old for explaining the concept and giving benefits of flexible design for modification/renovation work of building.

Keywords: flexibility, future saving, flexibility cost, construction projects

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Authors: Dionysios Kakaroumpas, Jesseka Farago, Stephen Webber

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Athletes and spectators depend on the tennis ranking system to represent the truest caliber of athletic prowess; a careful look at the current ranking system though, reveals its main weakness: it undermines expectations of fans and players. Our study proposes several key changes to the existing ranking formula that provide a fair and accurate approach to measure player performance. The study proposes a modification of the system to value: participation, continued advancement, and overall achievement. The new ranking formula facilitates closing the trust gap, encouraging competition equality, engaging the fan base, attracting investment, and promoting tennis involvement worldwide. To probe the crux of our main contention we performed week-by-week comparisons between results procured from the current and proposed formulae. After performing this rigorous case-study of top players of each gender, the findings strongly indicated that there is identifiable inflation in the ranks and enhanced the conviction that the current system should be updated. The new system is accompanied by a web-based software package freely available to anyone involved or interested in tennis rankings. The software package is designed to automatically calculate new player rankings based on a responsive, multi-faceted formula that also generates projected point scenarios and provides separate rankings for the three different court surfaces. By taking a critical look at the current tennis ranking system with consideration to the perspective of fans, players, and businesses involved, an upgrade is in order for it to maintain the balance of trust between fans and the evaluation process. In closure, this proposed solution increases fair play competition, eliminates rank inflation, and better engages fans, players, and sponsors by bringing in a new era of professional tennis.

Keywords: measurement and evaluation, rules and regulations, sports management and marketing, tennis ranking system

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Authors: Piotr Ciuman, Barbara Lipska

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The aim of presented research was to improve numerical predictions of air parameters distribution in the actual natatorium by the selection of calculation formula of mass flux of moisture emitted from the pool. Selected correlation should ensure the best compliance of numerical results with the measurements' results of these parameters in the facility. The numerical model of the natatorium was developed, for which boundary conditions were prepared on the basis of measurements' results carried out in the actual facility. Numerical calculations were carried out with the use of ANSYS CFX software, with six formulas being implemented, which in various ways made the moisture emission dependent on water surface temperature and air parameters in the natatorium. The results of calculations with the use of these formulas were compared for air parameters' distributions: Specific humidity, velocity and temperature in the facility. For the selection of the best formula, numerical results of these parameters in occupied zone were validated by comparison with the measurements' results carried out at selected points of this zone.

Keywords: experimental validation, indoor swimming pool, moisture emission, natatorium, numerical calculations CFD, thermal and humidity conditions, ventilation

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Authors: Indira priyadarshini, B. Tulja Lal, K. Anusha, P. Sai Varun

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Formula One cars are the fastest road course racing cars in the world, owing to very high cornering speeds achieved through the generation of large amounts of aerodynamic downforce. The main intentions and goals of this paper are to reduce the accidents and improving the safety without affecting the visibility of the driver by redesigning Halo that was developed by Mercedes in conjunction with the FIA to deflect flying debris, such as a loose wheel, away from a driver’s head while the hinged locking mechanism can quickly be removed for easy access. Halo design has been modified in order to reduce the weight without affecting the aerodynamics of the car. CFD simulation is carried out to observe the flow over the Halo. The velocity profile and pressure contours were analyzed. Halo is designed using SOLIDWORKS Furthermore, using the software ANSYS FLUENT 3D simulation of the airflow contour around the Halo in order to make changes in the geometry to improve the design by reducing air resistance and improving aerodynamics. According to our assumption, new 3D Halo model has better aerodynamic properties in order to analyse possible improvements compared to the initial design. Structural analysis is also done by using ANSYS by making an F1 tire colliding with Halo at 225 kmph in order to know the deflections in the structure.

Keywords: aerodynamics, Halo, safety, visibility

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Authors: Ritu Vashistha, Jitender Kumar

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Clustering using the K-means algorithm is a very common way to understand and analyze the obtained output data. When a similar object is grouped, this is called the basis of Clustering. There is K number of objects and C number of cluster in to single cluster in which k is always supposed to be less than C having each cluster to be its own centroid but the major problem is how is identify the cluster is correct based on the data. Formulation of the cluster is not a regular task for every tuple of row record or entity but it is done by an iterative process. Each and every record, tuple, entity is checked and examined and similarity dissimilarity is examined. So this iterative process seems to be very lengthy and unable to give optimal output for the cluster and time taken to find the cluster. To overcome the drawback challenge, we are proposing a formula to find the clusters at the run time, so this approach can give us optimal results. The proposed approach uses the Euclidian distance formula as well melanosis to find the minimum distance between slots as technically we called clusters and the same approach we have also applied to Ant Colony Optimization(ACO) algorithm, which results in the production of two and multi-dimensional matrix.

Keywords: ant colony optimization, data clustering, centroids, data mining, k-means

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Authors: Aniketh Ravukutam, Rajath Rao M., Pradyumna S. A.

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In the past few decades there has been great advancement in use of aerodynamics in cars. Now its use has been evident from commercial cars to race cars for achieving higher speeds, stability and efficiency. This paper focusses on studying the effects of aerodynamics in Formula Student car. These cars weigh around 200kgs with an average speed of 60kmph. With increasing competition every year, developing a competitive car is a herculean task. The race track comprises mostly of tight corners and little or no straights thus testing the car’s cornering capabilities. Higher cornering speeds can be achieved by increasing traction at the tires. Studying the aerodynamics helps in achieving higher traction without much addition in overall weight of car. The main focus is to develop an aerodynamic package involving front wing, under tray and body to obtain an optimum value of down force. The initial process involves the detail study of geometrical constraints mentioned in the rule book and calculating the limiting value of drag as per the engine specifications. The successive steps involve conduction of various iterations in ANSYS for selection of airfoils, deciding the number of elements, designing the nose for low drag, channelizing the flow under the body and obtain an optimum value of down force within the limits defined in the initial process. The final step involves design of model using these results in Virtual environment called OptimumLap® for detailed study of performance with and without the presence of aerodynamics. The CFD analysis results showed an overall down force of 377.44N with a drag of 164.08N. The corresponding parameters of the last model were applied in OptimumLap® and an improvement of 3.5 seconds in lap times was observed.

Keywords: aerodynamics, formula student, traction, front wing, undertray, body, rule book, drag, down force, virtual environment, computational fluid dynamics (CFD)

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Authors: Farhad Shafiepour Motlagh, Narges Salehi

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The aim of the present study was to investigate the relationship between inspirational leadership style and perceived social capital through the mediation of organizational knowledge resource development. The research method was descriptive-correlational. The statistical population consisted of all 3537 secondary school teachers in Isfahan. Sample selection was based on Cochran's formula volume formula for 338 people and multi-stage random sampling. The research instruments included a researcher-made inspirational leadership style questionnaire, a perceived social capital questionnaire (Putnam, 1999), and a researcher-made questionnaire of perceived organizational knowledge resources. Kolmogorov statistical tests, Pearson correlation, stepwise multiple regression, and structural equation modeling were used to analyze the data. In general, the results showed that there is a significant relationship between inspirational leadership style and the use of perceived social capital at the level of P <0.05. Also, the development of organizational knowledge resources mediates the relationship between inspirational leadership style and the use of perceived social capital at the level of P <0.05.

Keywords: inspirational leadership style, perceived social capital, perceived organizational knowledge

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Authors: Aida Nurul Safitri, Rosita Sari

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Physics is science, which in its learning there are some product such as theory, fact, concept, law and formula. So that to understand physics lesson students not only need a theory or concept but also mathematical calculation to solve physics problem through formula or equation. This is can be taken from mathematics lesson which obtained by students. This research is to know the influence of mathematics learning outcomes towards physics ability in Senior High School through authentic assessment system. Based on the researches have been discussed, is obtained that mathematic lesson have an important role in physics learning but it according to one aspect only, namely cognitive aspect. In Indonesia, curriculum of 2013 reinforces displacement in the assessment, from assessment through test (measuring the competence of knowledge based on the result) toward authentic assessment (measuring the competence of attitudes, skills, and knowledge based on the process and results). In other researches are mentioned that authentic assessment system give positive responses for students to improve their motivation and increase the physics learning in the school.

Keywords: authentic assessment, curriculum of 2013, mathematic, physics

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Authors: Shinji Kajiwara, Tadamasa Fukuoka

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The formula project of Kinki University has been involved in the student Formula SAE of Japan (JSAE) since the second year the competition was held. The vehicle developed in the project uses a ZX-6R engine, which has been manufactured by Kawasaki Heavy Industries for the JSAE competition for the eighth time. The limited performance of the concept vehicle was improved through the development of a power train. The supercharger loading, engine dry sump, and engine cooling management of the vehicle were also enhanced. The supercharger loading enabled the vehicle to achieve a maximum output of 59.6 kW (80.6 PS)/9000 rpm and a maximum torque of 70.6 Nm (7.2 kgf m)/8000 rpm. We successfully achieved 90% of the engine’s torque band (4000–10000 rpm) with 50% of the revolutions in regular engine use (2000–12000 rpm). Using a dry sump system, we periodically managed hydraulic pressure during engine operation. A system that controls engine stoppage when hydraulic pressure falls was also constructed. Using the dry sump system at 80 mm reduced the required engine load and the vehicle’s center of gravity. Even when engine motion was suspended by the electromotive force exerted by the water pump, the circulation of cooling water was still possible. These findings enabled us to create a cooling system in accordance with the requirements of the competition.

Keywords: engine, combustion, cooling system, numerical simulation, power, torque, mechanical super charger

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Authors: Hamid Ahmadi, Neda Azari Dodaran

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This paper aims to study the structural behavior of tubular KT-joints subjected to axial loading at fire induced elevated temperatures. At first, a finite element (FE) model was developed and validated against the data available from experimental tests. Then, a set of 810 FE analyses were performed to study the influence of temperature and dimensionless geometrical parameters (β, γ, θ, and τ) on the ultimate strength and initial stiffness. The joints were analyzed under two types of axial loading and five different temperatures (20 ºC, 200 ºC, 400 ºC, 550 ºC, and 700 ºC). Results show that the ultimate strength and initial stiffness of KT-joints decrease considerably by increasing the temperature. In the joints having bigger values of the β, the temperature elevation leads to less reduction in ultimate strength; while in the joints with bigger values of the γ, the temperature elevation results in more reduction in ultimate strength. The influence of the θ on the ultimate strength is independent from the temperature. To our knowledge, there is no design formula available for determining the ultimate strength of KT-joints at elevated temperatures. Hence, after parametric study, two equations were developed through nonlinear regression, for calculating the ultimate strength of KT-joints at elevated temperatures.

Keywords: axial loads, fire condition, parametric formula, static strength, tubular KT-joint

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Authors: Maha Awad M. Almuttairi

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This research aimed to measure the impact of the use of a mobile learning (iTunes U) app for the development of metacognition skills delivered in the enrichment program offered to gifted students at the secondary level in Jeddah. The author targeted a group of students on an experimental scale to evaluate the achievement. The research sample consisted of a group of 38 gifted female students. The scale of evaluation of the metacognition skills used to measure the performance of students in the enrichment program was as follows: Satisfaction scale for the assessment of the technique used and the final product form after completion of the program. Appropriate statistical treatment used includes Paired Samples T-Test Cronbach’s alpha formula and eta squared formula. It was concluded in the results the difference of α≤ 0.05, which means the performance of students in the skills of metacognition in favor of using iTunes U. In light of the conclusion of the experiment, a number of recommendations and suggestions were present; the most important benefit of mobile learning applications is to provide enrichment programs for gifted students in the Kingdom of Saudi Arabia, as well as conducting further research on mobile learning and gifted student teaching.

Keywords: enrichment program, gifted students, metacognition skills, mobile learning

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Authors: Hrishit Mitra, Saptarshi Mandal

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The study of aerodynamics for Formula 1 cars is very crucial in determining their performance. In the current F1 industry, when each engine manufacturer exhibits a torque and peak speed that differ by less than 5%, the emphasis on maximizing performance is dependent heavily on the utilization of aerodynamics. This work examines the aerodynamic characteristics of an F1 car by utilizing computational fluid dynamics in order to substantiate the hypothesis that an F1 car can go upside down in a tunnel without any external assistance, only due to the downforce it produces. In addition to this, this study also suggests the implementation of a 'flexi-wing' front in F1 cars to optimize downforce and reduce drag. Furthermore, this paper provides a concise overview of the historical development of aerodynamics in F1, with a specific emphasis on the progression of aerodynamics and the impact of downforce on the dynamics of vehicles. Next, an examination of wings has been provided, comparing the performance of the suggested wing at high speeds and low speeds. Three simulations have been conducted: one to test the complete aerodynamics and validate the hypothesis discussed above, and two specifically focused on the flexi wing, one at high speed and one at low speed. The collected results have been examined to analyze the performance of the front flexi wing. Performance analysis was conducted from the measurement of downforce and drag coefficient, as well as the pressure and velocity distributions.

Keywords: high speed flexi wing, low speed flexi wing, F1 car aerodynamics, F1 car drag reduction

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Authors: Ashraf Mohammed M. Eid, Hossam El Badry

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The bored pile friction resistance may be affected by many factors such as the method of construction, pile length and diameter, the soil properties, as well as the depth below ground level. These factors can be represented analytically to study the influence of diameter on the unit skin friction. In this research, the Egyptian Code of soil mechanics is used to assess the skin friction capacity for either the ordinary pile diameter as well as for the large pile diameter. The later is presented in the code and through the work of some researchers based on the results of investigations adopted for a sufficient number of field tests. The comparative results of these researchers with respect to the Egyptian Code are used to check the adequacy of both methods. Based on the results of this study, the traditional static formula adopted for piles of diameter less than 60 cm may be continually used for larger piles by correlating the analyzed formulae. Accordingly, the corresponding modified angle of internal friction is concluded demonstrating a reduction of shear strength due to soil disturbance along the pile shaft. Based on this research the difference between driven piles and bored piles constructed in same soil can be assessed and a better understanding can be evaluated for the effect of different factors on pile skin friction capacity.

Keywords: large piles, static formula, friction piles, sandy soils

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Authors: Pin-Wei Chiang, Wen-Liang Chang, Ruey-Huei Yeh

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This paper investigates optimal replacement and preventative maintenance policies of secondhand products under a Finite Planning Horizon (FPH). Any consumer wishing to replace their product under FPH would have it undergo minimal repairs. The replacement provided would be required to undergo periodical preventive maintenance done to avoid product failure. Then, a mathematical formula for disbursement cost for products under FPH can be derived. Optimal policies are then obtained to minimize cost. In the first of two segments of the paper, a model for initial product purchase of either new or secondhand products is used. This model is built by analyzing product purchasing price, surplus value of product, as well as the minimal repair cost. The second segment uses a model for replacement products, which are also secondhand products with no limit on usage. This model analyzes the same components as the first as well as expected preventative maintenance cost. Using these two models, a formula for the expected final total cost can be developed. The formula requires four variables (optimal preventive maintenance level, preventive maintenance frequency, replacement timing, age of replacement product) to find minimal cost requirement. Based on analysis of the variables using the expected total final cost model, it was found that the purchasing price and length of ownership were directly related. Also, consumers should choose the secondhand product with the higher usage for replacement. Products with higher initial usage upon acquisition require an earlier replacement schedule. In this case, replacements should be made with a secondhand product with less usage. In addition, preventative maintenance also significantly reduces cost. Consumers that plan to use products for longer periods of time replace their products later. Hence these consumers should choose the secondhand product with lesser initial usage for replacement. Preventative maintenance also creates significant total cost savings in this case. This study provides consumers with a method of calculating both the ideal amount of usage of the products they should purchase as well as the frequency and level of preventative maintenance that should be conducted in order to minimize cost and maintain product function.

Keywords: finite planning horizon, second hand product, replacement, preventive maintenance, minimal repair

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Authors: Wipharat Saimo, Benjawan Thumthanaruk, Panida Banjongsinsiri, Nowwapan Noojuy

Abstract:

Thai northern style sausage (sai-ou) is originally cuisine made of chili paste, pork, and lard. It always serves with curry paste, vegetable, and rice. The meat and lard ingredients used can be substituted by Shiitake mushroom (Lentinus edodes) and King oyster (Pleurotus eryngii) mushroom (50:50 w/w) which is suitable for all people, especially vegetarians. However, the texture of mushroom type sai-ou had no homogenous texture due to no adhesiveness property of mushroom. Therefore, this research aimed to study the ratio of hydrocolloids (konjac flour (0-100%), konjac gel (0-100%) and Citri-fi®100 FG (0-2%)) on the physicochemical properties mushroom type sai-ou. The mixture design was applied by using Minitab 16 software. Nine formula were designed for the test. The values of moisture content and water activity of nine formula were ranged from 66.25-72.17% and 0.96-0.97. The pH values were 5.44-5.89. The optimal ratio of konjac flour, konjac gel and Citri-fi®100 FG (74.75:24.75:0.5 (w/w)) yielded the highest texture profiles (hardness, springiness, cohesiveness, gumminess and chewiness) as well as color parameters (L*, a* and b*). Sensory results showed had higher acceptability scores in term of overall liking with the level of ‘like moderately’ (5.9 on 7 pointed scale). The mushroom type sai-ou sausage could be an alternative food for health-conscious consumers.

Keywords: Citri-fi® 100 FG, konjac flour, konjac gel, Thai northern style sausages

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Authors: Aji Budi Rinekso, Revika Niza Artiyana, Lisa Widayanti

Abstract:

English is one of the international languages in the world. People use this language to communicate with each other in the international forums, international events or international organizations. As same as other languages, English has a rule which is called grammar. Grammar is the part of english which has a role as the language systems. In grammar, there are tenses which provide a time period system for past, present and future. Sometimes it is difficult for some English learner to remember all of the tenses completely. Especially for those with special needs or exceptional children with vision restrictiveness. The aims of this research are 1) To know the design of Special Grammar Circle (Spegraci) as the media for blind people to learn english grammar. 2) To know the work of Special Gramar Circle (Spegraci) as the media for blind people to learn english grammar. 3) To know the function of this device in increasing tenses ability for blind people. The method of this research is Research and Development which consists of several testing and revision of this device. The implementation of Special Grammar Circle (Spegraci) is to make blind people easily to learn the tenses. This device is easy to use. Users only roll this device and find out the tense formula and match to the name of the formula in braille. In addition, this device also enables to be used by normal people because normal written texts are also provided.

Keywords: blind people, media innovation, spegraci, tenses

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Authors: Harminder Kaur, Manpreet Kaur, Akanksha Kapila, Reenu

Abstract:

Schiff base with general formula H₂L was derived from condensation of o-vanillin and 3-nitro-o-phenylenediamine. This Schiff base was used for the synthesis of organotin(IV) complexes with general formula R₂SnL [R=Phenyl or n-octyl] using equimolar quantities. Elemental analysis UV-Vis, FTIR, and multinuclear spectroscopic techniques (¹H, ¹³C, and ¹¹⁹Sn) NMR were carried out for the characterization of the synthesized complexes. These complexes were coloured and soluble in polar solvents. Computational studies have been performed to obtain the details of the geometry and electronic structures of ligand as well as complexes. Geometry of the ligands and complexes have been optimized at the level of Density Functional Theory with B3LYP/6-311G (d,p) and B3LYP/MPW1PW91 respectively followed by vibrational frequency analysis using Gaussian 09. Observed ¹¹⁹Sn NMR chemical shifts of one of the synthesized complexes showed tetrahedral geometry around Tin atom which is also confirmed by DFT. HOMO-LUMO energy distribution was calculated. FTIR, ¹HNMR and ¹³CNMR spectra were also obtained theoretically using DFT. Further IRC calculations were employed to determine the transition state for the reaction and to get the theoretical information about the reaction pathway. Moreover, molecular docking studies can be explored to ensure the anticancer activity of the newly synthesized organotin(IV) complexes.

Keywords: DFT, molecular docking, organotin(IV) complexes, o-vanillin, 3-nitro-o-phenylenediamine

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Authors: P. Jayaram, Prasoon Prasannan, N. K. Deepak, P. P. Pradyumnan

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Indium and Zirconium co doped zinc oxide (InZrZnO) thin films are prepared by chemical spray pyrolysis method on pre-heated quartz substrates. The films are subjected to vacuum annealing at 400ᵒC for three hours in an appropriate air (10-5mbar) ambience after deposition. X-ray diffraction, Scanning electron microscopy, energy dispersive spectra and photoluminescence are used to characterize the films. Temperature dependent electrical measurements are conducted on the films and the films exhibit exceptional conductivity at higher temperatures. XRD analysis shows that all the films prepared in this work have hexagonal wurtzite structure. The average crystallite sizes of the films were calculated using Scherrer’s formula, and uniform deformation model (UDM) of Williamson-Hall method is used to establish the micro-strain values. The dislocation density is determined from the Williamson and Smallman’s formula. Intense, broad and strongly coupled multiple photoluminescence were observed from photoluminescence spectra. PL indicated relatively high concentration defective oxygen and Zn vacancies in the film composition. Strongly coupled ultraviolet near blue emissions authenticate that the dopants are capable of inducing modulated free excitonic (FX), donor accepter pair (DAP) and longitudinal optical phonon emissions in thin films.

Keywords: PL, SEM, TCOs, thin films, XRD

Procedia PDF Downloads 238