Search results for: switching flux permanent magnet (SFPM) motor

Authors: Aaidha Hammad

Abstract:

This study examines the phenomenon of code switching among teenagers in the Maldives while they carry out conversations through Facebook in the form of “Facebook Chatting”. The current study aims at evaluating the frequency of code-switching and it investigates between what languages code-switching occurs. Besides the study identifies the types of words that are often codeswitched and the triggers for code switching. The methodology used in this study is mixed method of qualitative and quantitative approach. In this regard, the chat log of a group conversation between 10 teenagers was collected and analyzed. A questionnaire was also administered through online to 24 different teenagers from different corners of the Maldives. The age of teenagers ranged between 16 and 19 years. The findings of the current study revealed that while Maldivian teenagers chat in Facebook they very often code switch and these switches are most commonly between Dhivehi and English, but some other languages are also used to some extent. It also identified the different types of words that are being often code switched among the teenagers. Most importantly it explored different reasons behind code switching among the Maldivian teenagers in Facebook chatting.

Keywords: code-switching, Facebook, Facebook chatting Maldivian teenagers

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Authors: Shefeen Maliyakkal, Pranav Satheesh, Steve Simon, Sharath Kuruppath

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This paper researches the impact of battery voltage sag on the performance and efficiency of E-motor in electric cars. Terminal voltage of battery reduces with the S.o.C. This results in the downward shift of torque-speed curve of E-motor and increased copper losses in E-motor. By introducing a buck-boost inverter between the battery and E-motor, an additional degree of freedom was achieved. By boosting the AC voltage, the dependency of voltage sag on the performance of E-motor was eliminated. A strategy was also proposed for the operation of the buck-boost inverter to minimize copper and iron losses in E-motor to maximize efficiency. MATLAB-SIMULINK model of E-drive was used to obtain simulation results. The temperature rise in the E-motor was reduced by 14% for a 10% increase in AC voltage. From the results, it was observed that a 20% increase in AC voltage can result in improvement of running torque and maximum torque of E-motor by 44%. Hence it was concluded that using a buck-boost inverter for E-drive significantly improves both performance and efficiency of E-motor.

Keywords: buck-boost, E-motor, battery, voltage sag

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Authors: H. Fazlinejad, A. Halvaee

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In this study, characteristics of ATIG welds using ZnO flux on aluminum was investigated and compared with TIG welds. Autogenously AC-ATIG bead on plate welding was applied on Al1050 plate with a coating of ZnO as the flux. Different levels of welding current and flux layer thickness was considered to study the effect of heat input and flux quantity on ATIG welds and was compared with those of TIG welds. Geometrical investigation of the weld cross sections revealed that penetration depth of the ATIG welds with ZnO flux, was increased up to 2 times in some samples compared to the TIG welds. Optical metallographic and Scanning Electron Microscopy (SEM) observations revealed similar microstructures in TIG and ATIG welds. Composition of the ATIG welds slag was also analyzed using X-ray diffraction. In both TIG and ATIG samples, the lowest values of microhardness were observed in the HAZ.

Keywords: ATIG, active flux, weld penetration, Al 1050, ZnO

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Authors: Ali Asghar Memon

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The simulation modeling of switched reluctance (SR) machine often relies and uses the three data tables identified as static torque characteristics that include flux linkage characteristics, co energy characteristics and static torque characteristics separately. It has been noticed from the literature that the data of static torque used in the simulation model is often calculated so far the literature is concerned. This paper presents the simulation model that include the data of measured and calculated static torque separately to see its effect on instantaneous torque profile of the machine. This is probably for the first time so far the literature review is concerned that static torque from co energy information, and measured static torque directly from experiments are separately used in the model. This research is helpful for accurate modeling of switched reluctance drive.

Keywords: static characteristics, current chopping, flux linkage characteristics, switched reluctance motor

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Authors: Sebastian Kehne, Alexander Epple, Werner Herfs

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A new method for optimal selection of components for multi-axes forward-feed drive systems is proposed in which the choice of motors, gear boxes and ball screw drives is optimized. Essential is here the synchronization of electrical and mechanical frequency behavior of all axes because even advanced controls (like H∞-controls) can only control a small part of the mechanical modes – namely only those of observable and controllable states whose value can be derived from the positions of extern linear length measurement systems and/or rotary encoders on the motor or gear box shafts. Further problems are the unknown processing forces like cutting forces in machine tools during normal operation which make the estimation and control via an observer even more difficult. To start with, the open source Modelica Feed Drive Library which was developed at the Laboratory for Machine Tools, and Production Engineering (WZL) is extended from one axis design to the multi axes design. It is capable to simulate the mechanical, electrical and thermal behavior of permanent magnet synchronous machines with inverters, different gear boxes and ball screw drives in a mechanical system. To keep the calculation time down analytical equations are used for field and torque producing equivalent circuit, heat dissipation and mechanical torque at the shaft. As a first step, a small machine tool with a working area of 635 x 315 x 420 mm is taken apart, and the mechanical transfer behavior is measured with an impulse hammer and acceleration sensors. With the frequency transfer functions, a mechanical finite element model is built up which is reduced with substructure coupling to a mass-damper system which models the most important modes of the axes. The model is modelled with Modelica Feed Drive Library and validated by further relative measurements between machine table and spindle holder with a piezo actor and acceleration sensors. In a next step, the choice of possible components in motor catalogues is limited by derived analytical formulas which are based on well-known metrics to gain effective power and torque of the components. The simulation in Modelica is run with different permanent magnet synchronous motors, gear boxes and ball screw drives from different suppliers. To speed up the optimization different black-box optimization methods (Surrogate-based, gradient-based and evolutionary) are tested on the case. The objective that was chosen is to minimize the integral of the deviations if a step is given on the position controls of the different axes. Small values are good measures for a high dynamic axes. In each iteration (evaluation of one set of components) the control variables are adjusted automatically to have an overshoot less than 1%. It is obtained that the order of the components in optimization problem has a deep impact on the speed of the black-box optimization. An approach to do efficient black-box optimization for multi-axes design is presented in the last part. The authors would like to thank the German Research Foundation DFG for financial support of the project “Optimierung des mechatronischen Entwurfs von mehrachsigen Antriebssystemen (HE 5386/14-1 | 6954/4-1)” (English: Optimization of the Mechatronic Design of Multi-Axes Drive Systems).

Keywords: ball screw drive design, discrete optimization, forward feed drives, gear box design, linear drives, machine tools, motor design, multi-axes design

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Authors: Nakarin Prempri

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Single-phase induction motors are widely used in industry. Most manufacturing processes use capacitor-run single-phase induction motors to drive mechanical loads. The selection of a suitable motor for driving is important. The optimum operating range of the motor can help the motor operate efficiently. Thus, this paper presents an operating range analysis of capacitor-run single-phase induction motors and a determination of suitability between motor and mechanical loads. an observational study found that the optimum operating range of the motor can be used to determine the suitability between the motor and the mechanical load. Such considerations ensure that the motor uses no more current than necessary and operates efficiently.

Keywords: single phase induction motor, operating range, torque curve, efficiency curve

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Authors: Gondu Vykunta Rao, Madhuri Bayya, Aruna Bharathi M., Paramesw Chidamparam, B. Murali

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The increase in software content in today’s electric vehicles is increasing attention to having vast, unique topographies from low emission to high efficiency, whereas the chemical batteries have huge short comes, such as limited cycle life, power density, and cost. As for understanding and visualization, the companies are turning toward the virtual vehicle to test their design in software which is known as a simulation in the loop (SIL). In this project, in addition to the electric vehicle (EV) technology, we are adding a dynamo with the vehicle for regenerative braking. Traditionally the principle of dynamos is used in lighting the purpose of the bicycle. Here by using the same mechanism, we are running the vehicle as well as charging the vehicle from system-level simulation to the model in the loop and then to the Hardware in Loop (HIL) by using model-based development.

Keywords: electric vehicle, simulation in the loop (SIL), model in loop (MIL), hardware in loop (HIL), dynamos, model-based development (MBD), permanent magnet synchronous motor (PMSM), current control (CC), field-oriented control (FOC), regenerative braking

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Authors: Rachid Taleb, M’hamed Helaimi, Djilali Benyoucef, Ahmed Derrouazin

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Multilevel inverters are well used in high power electronic applications because of their ability to generate a very good quality of waveforms, reducing switching frequency, and their low voltage stress across the power devices. This paper presents the Optimal Minimization of the Total Harmonic Distortion (OMTHD) strategy of a uniform step asymmetrical seven-level inverter (USA7LI). The OMTHD approach is compared to the well-known sinusoidal pulse-width modulation (SPWM) strategy. Simulation results demonstrate the better performances and technical advantages of the OMTHD controller in feeding a High Power Induction Motor (HPIM).

Keywords: uniform step asymmetrical seven-level inverter (USA7LI), optimal minimization of the THD (OMTHD), sinusoidal PWM (SPWM), high power induction motor (HPIM)

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Authors: Anjali Sharma, R. R. K. Sharma

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The purpose of this study is to examine relationships between personality factors and customer switching for services. Earlier research was directed towards establishing relationship between individual personality traits and customer switching variables considering five-factors model comprised of five personality dimensions (OCEAN), in which personality was not the only influencing factor. Moreover, these works were found to be focused on products and not services. In contrast, the current study is aimed at investigating role of personality using Myer Briggs Type indicator (MBTI) as well as Five-Big Factors, on customer switching and building the conceptual framework on services rather than products. MBTI also known as four opposite pairs or dichotomies of personality dimensions are studied using different levels Involvement (High, Low) of consumer and Value of service-offering (Value for money and Premium) as moderators associated with Consumer Switching. The study is unique in sense that consequences of these indicators of personality on switching behavior has never been studied using considering moderating effect of involvement and value of services. According to our prepositions for a more Extrovert, Intuitive Personality the switching is going to be high whereas the switching is going to be less for an Introvert, Judgmental kind of personality. Similarly, for a consumer with high Neuroticism and Agreeableness the switching would be less as compared to an Open and Conscious Personality type. These level differs with level of a consumer’s involvement and type of a service being offered based on its value.

Keywords: consumer switching, involvement, Myer Briggs personality type indicators, personality, value of service

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Authors: Shehroz Mukhtar, Maqsood Ahmed, Abdullah Mukhtar, Choudhry Shahid, Waqar Javaid

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Code switching is a common phenomenon, generally observed in multilingual communities across the globe. A critical look at code switching literature reveals that mostly code switching has been studied in classroom in learning and teaching context while code switching outside classroom in settings such as café, hostel and so on have been the least explored areas. Current research investigated the reasons for code switching in the interactive practices of students and their perceptions regarding the same outside the classroom settings. This paper is the study of the common practice that prevails in the Universities of Sialkot that bilinguals mix two languages when they speak in different class room situations. In Pakistani classrooms where Multilingual are in abundance i.e. they can speak two or more than two languages at the same time, the code switching or language combination is very common. The teachers of Sialkot switch from one language to another consciously or unconsciously while teaching English in the class rooms. This phenomenon has not been explored in the Sialkot’s teaching context. In Sialkot private educational institutes does not encourage code-switching whereas the public or government institutes use it frequently. The crux of this research is to investigate and identify the importance of code switching by taking its users in consideration. Survey research method and survey questionnaire will be used to get exact data from teachers and students. We will try to highlight the functions and importance of code switching in foreign language classrooms of Sialkot and will explore why this trend is emerging in Sialkot.

Keywords: code switching, bilingual context, L1, L2

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Authors: Shehroz Mukhtar, Maqsood Ahmed, Abdullah Mukhtar, Choudhry Shahid, Waqar Javaid

Abstract:

Code switching is a common phenomenon, generally observed in multilingual communities across the globe. A critical look at code-switching literature reveals that mostly code-switching has been studied in the classrooms in learning and teaching contexts, while code-switching outside the classroom in settings such as café, hostels and so on has been the least explored areas. The current research investigated the reasons for code-switching in the interactive practices of students and their perceptions regarding the same outside the classroom settings. This paper is the study of the common practice that prevails in the Universities of Sialkot that bilinguals mix two languages when they speak in different classroom situations. In Pakistani classrooms where Multilingual is in abundance, i.e. they can speak two or more two languages at the same time, code-switching or language combination is very common. The teachers of Sialkot switch from one language to another consciously or unconsciously while teaching English in the classrooms. This phenomenon has not been explored in Sialkot’s teaching context. In Sialkot, private educational institutes do not encourage code-switching, whereas public or government institutes use it frequently. The crux of this research is to investigate and identify the importance of code-switching by taking its users into consideration. The survey research method and survey questionnaire will be used to get exact data from teachers and students. We will try to highlight the functions and importance of code switching in foreign language classrooms of Sialkot and will explore why this trend is emerging in Sialkot.

Keywords: code switching, foreign language classrooms, bilingual context, use of L1, importance of L2.

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Authors: Jan Doutreloigne

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The main goal of this paper is to develop a switching amplifier with optimized power efficiency for analog signals with a very high crest factor such as audio or DSL signals. Theoretical calculations show that a switching amplifier architecture based on multi-level pulse width modulation outperforms all other types of linear or switching amplifiers in that respect. Simulations on a 2 W multi-level switching audio amplifier, designed in a 50 V 0.35 mm IC technology, confirm its superior performance in terms of power efficiency. A real silicon implementation of this audio amplifier design is currently underway to provide experimental validation.

Keywords: audio amplifier, multi-level switching amplifier, power efficiency, pulse width modulation, PWM, self-oscillating amplifier

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Authors: Rohollah Asadian Kohestani, Mustafa Hashemzadeh

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The present paper is the outcome of a field research that was conducted with the study objective of influencing factor's effect on the behavior of customers switching in the Saipa Emdad Khodro Company. To achieve this goal, six factors of service quality, service cost, waiting time to receive services, reputation of organization, costs of switching and the way to respond the needs of customers as the independent variables of research and their effect on the customer switching was studied as the variable related to the research. The statistical society of this research included all customers of the Saipa Emdad Khodro company that possess the vehicles of automobile manufacturing group of Saipa throughout the country and the statistical sample included 150 persons of such customers. The results of this research indicated that all under study factors excluding the reputation factor effect on the behavior of customer switching.

Keywords: customer services, switching cost, service price, customer switching behavior

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Authors: Meetty Tomy, Arxhana G Thosar

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This paper provides the implementation of optimal control for an armature-controlled DC motor. The selection of error weighted Matrix and control weighted matrix in order to implement optimal control theory for improving the dynamic behavior of DC motor is presented. The closed loop performance of Armature controlled DC motor with derived linear optimal controller is then evaluated for the transient operating condition (starting). The result obtained from MATLAB is compared with that of PID controller and simple closed loop response of the motor.

Keywords: optimal control, DC motor, performance index, MATLAB

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Authors: Numra Qayyum, Samina Sarwat, Noor ul Ain

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Bilingual speakers generally can speak both languages with the same competency without mixing them intentionally and making mistakes, but sometimes errors occur in language selection. This quantitative study particularly deals with the language errors made by Urdu-English bilinguals. In this research, researchers have given special attention to the part played by bottom-up priming and top-down cognitive control in these errors. Unstable Urdu-English bilingual participants termed pictures and were prompted to shift from one language to another under the pressure of time. Different situations were given to manipulate the participants. The long and short runs trials of the same language were also given before switching to another language. The study is concluded with the findings that bilinguals made more errors when switching to the first language from their second language, and these errors are large in number, especially when a speaker is switching from L2 (second language) to L1 (first language) after a long run. When the switching is reversed, i.e., from L2 to LI, it had no effect at all. These results gave the clear responsibility of all these errors to top-down cognitive control.

Keywords: bottom up priming, language error, language switching, top down cognitive control

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Authors: Wei Zheng, Mao Ji, Zhe Hou, Meng Huang, Bo Qi

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The transformer is the key equipment of the power system. Winding deformation is one of the main transformer defects, and timely and effective detection of the transformer winding deformation can ensure the safe and stable operation of the transformer to the maximum extent. When winding deformation occurs, the size, shape and spatial position of the winding will change, which directly leads to the change of magnetic flux leakage distribution. Therefore, it is promising to study the online detection method of the transformer winding deformation based on magnetic flux leakage characteristics, in which the key step is to study the optimal placement method of magnetic flux leakage sensors inside the transformer. In this paper, a simulation model of the transformer winding deformation is established to obtain the internal magnetic flux leakage distribution of the transformer under normal operation and different winding deformation conditions, and the law of change of magnetic flux leakage distribution due to winding deformation is analyzed. The results show that different winding deformation leads to different characteristics of the magnetic flux leakage distribution. On this basis, an optimized placement of magnetic flux leakage sensors inside the transformer is proposed to provide a basis for the online detection method of transformer winding deformation based on the magnetic flux leakage characteristics.

Keywords: magnetic flux leakage, sensor placement method, transformer, winding deformation

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Authors: Chaouch Souad, Abdou Latifa, Larbi Chrifi Alaoui

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This paper deals with sensorless backstepping control of induction motor using MRAS technique associated to sliding mode approach. A high order genetic algorithm structure is used to approximate a control law designed by the Backstepping technique, and to find the best parameters globally optimized. However, the Backstepping control approach is unsuitable for high performance applications because the need of a speed sensor for increased accuracy and the absence of any error decay mechanism. In this paper a nonlinear observer, obtained by combining sliding mode structure and model reference adaptive system (MRAS), is designed for the rotor flux and rotor speed estimations. To validate the proposed method, the results are presented for showing the improved drive characteristics and performances.

Keywords: Backstepping Control, Induction Motor, Genetic Algorithm, Sliding Mode observer

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Authors: W. Kritsarikan, T. Patcharawit, T. Yingnakorn, S. Khumkoa

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Neodymium-iron-boron (NdFeB) magnets classified as high-power magnets are widely used in various applications such as electrical and medical devices and account for 13.5 % of the permanent magnet’s market. Since its typical composition of 29 - 32 % Nd, 64.2 – 68.5 % Fe and 1 – 1.2 % B contains a significant amount of rare earth metals and will be subjected to shortages in the future. Domestic NdFeB magnet waste recycling should therefore be developed in order to reduce social, environmental impacts toward a circular economy. Most research works focus on recycling the magnet wastes, both from the manufacturing process and end of life. Each type of wastes has different characteristics and compositions. As a result, these directly affect recycling efficiency as well as the types and purity of the recyclable products. This research, therefore, focused on the recycling of manufacturing NdFeB magnet waste obtained from the sintering stage of magnet production and the waste contained 23.6% Nd, 60.3% Fe and 0.261% B in order to recover high purity neodymium oxide (Nd₂O₃) using hybrid metallurgical process via oxidative roasting and selective leaching techniques. The sintered NdFeB waste was first ground to under 70 mesh prior to oxidative roasting at 550 - 800 °C to enable selective leaching of neodymium in the subsequent leaching step using H₂SO₄ at 2.5 M over 24 h. The leachate was then subjected to drying and roasting at 700 – 800 °C prior to precipitation by oxalic acid and calcination to obtain neodymium oxide as the recycling product. According to XRD analyses, it was found that increasing oxidative roasting temperature led to an increasing amount of hematite (Fe₂O₃) as the main composition with a smaller amount of magnetite (Fe₃O₄) found. Peaks of neodymium oxide (Nd₂O₃) were also observed in a lesser amount. Furthermore, neodymium iron oxide (NdFeO₃) was present and its XRD peaks were pronounced at higher oxidative roasting temperatures. When proceeded to acid leaching and drying, iron sulfate and neodymium sulfate were mainly obtained. After the roasting step prior to water leaching, iron sulfate was converted to form hematite as the main compound, while neodymium sulfate remained in the ingredient. However, a small amount of magnetite was still detected by XRD. The higher roasting temperature at 800 °C resulted in a greater Fe₂O₃ to Nd₂(SO₄)₃ ratio, indicating a more effective roasting temperature. Iron oxides were subsequently water leached and filtered out while the solution contained mainly neodymium sulfate. Therefore, low oxidative roasting temperature not exceeding 600 °C followed by acid leaching and roasting at 800 °C gave the optimum condition for further steps of precipitation and calcination to finally achieve neodymium oxide.

Keywords: NdFeB magnet waste, oxidative roasting, recycling, selective leaching

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Authors: Woranittha Kritsarikan

Abstract:

Neodymium-iron-boron (NdFeB) magnets classified as high-power magnets are widely used in various applications such as electrical and medical devices and account for 13.5 % of the permanent magnet’s market. Since its typical composition of 29 - 32 % Nd, 64.2 – 68.5 % Fe and 1 – 1.2 % B contains a significant amount of rare earth metals and will be subjected to shortages in the future. Domestic NdFeB magnet waste recycling should therefore be developed in order to reduce social, environmental impacts toward the circular economy. Most research works focus on recycling the magnet wastes, both from the manufacturing process and end of life. Each type of wastes has different characteristics and compositions. As a result, these directly affect recycling efficiency as well as the types and purity of the recyclable products. This research, therefore, focused on the recycling of manufacturing NdFeB magnet waste obtained from the sintering stage of magnet production and the waste contained 23.6% Nd, 60.3% Fe and 0.261% B in order to recover high purity neodymium oxide (Nd₂O₃) using hybrid metallurgical process via oxidative roasting and selective leaching techniques. The sintered NdFeB waste was first ground to under 70 mesh prior to oxidative roasting at 550 - 800 ᵒC to enable selective leaching of neodymium in the subsequent leaching step using H₂SO₄ at 2.5 M over 24 hours. The leachate was then subjected to drying and roasting at 700 – 800 ᵒC prior to precipitation by oxalic acid and calcination to obtain neodymium oxide as the recycling product. According to XRD analyses, it was found that increasing oxidative roasting temperature led to the increasing amount of hematite (Fe₂O₃) as the main composition with a smaller amount of magnetite (Fe3O4) found. Peaks of neodymium oxide (Nd₂O₃) were also observed in a lesser amount. Furthermore, neodymium iron oxide (NdFeO₃) was present and its XRD peaks were pronounced at higher oxidative roasting temperature. When proceeded to acid leaching and drying, iron sulfate and neodymium sulfate were mainly obtained. After the roasting step prior to water leaching, iron sulfate was converted to form hematite as the main compound, while neodymium sulfate remained in the ingredient. However, a small amount of magnetite was still detected by XRD. The higher roasting temperature at 800 ᵒC resulted in a greater Fe2O3 to Nd2(SO4)3 ratio, indicating a more effective roasting temperature. Iron oxides were subsequently water leached and filtered out while the solution contained mainly neodymium sulfate. Therefore, low oxidative roasting temperature not exceeding 600 ᵒC followed by acid leaching and roasting at 800 ᵒC gave the optimum condition for further steps of precipitation and calcination to finally achieve neodymium oxide.

Keywords: NdFeB magnet waste, oxidative roasting, recycling, selective leaching

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Authors: Nabil A. Ahmed

Abstract:

DC-DC converters are necessary to interface low-voltage fuel cell power generation systems to a higher voltage DC bus system. A system and method for generating a regulated output power from fuel cell power generation systems is proposed in this paper, this includes a soft-switching isolated DC-DC converter to reduce the idling and circulating currents. The system incorporates a high-frequency center tap transformer link DC-DC converter using secondary-side soft switching control. Snubber capacitors including the parasitic capacitance of the switching devices and the transformer leakage inductance are utilized to achieve zero-voltage switching (ZVS) in the primary side of the high-frequency transformer. Therefore, no extra resonant components are required for ZVS. The inherent soft-switching capability allows high power density, efficient power conversion, and compact packaging. A prototype rated at 6.5 kW is proposed and simulated. Simulation results confirmed a wide range of soft-switching operation and consequently high conversion efficiency will be achieved.

Keywords: secondary-side, phase-shift, high-frequency transformer, zero voltage, zero current, soft switching operation, switching losses

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Authors: Najib Belhadj Messaoud, Slim Souissi

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The non-linear dynamic behavior of a single stage spur gear reducer is studied in this paper in transient regime. Driving and driver rotors are, respectively, powered by a motor torque Cm and loaded by a resistive torque Cr. They are supported by two identical Active Magnetic Bearings (AMBs). Gear excitation is induced by the motor torque and load variation in addition to the fluctuation of meshing stiff-ness due to the variation of input rotational speed. Three models of AMBs were used with four, six and eight magnets. They are operated by P.D controller and powered by control and bias currents. The dynamic parameters of the AMBs are modeled by stiffness and damping matrices computed by the derivation of the electromagnetic forces. The equations of motion are solved iteratively using Newmark time integration method. In the first part of the study, the model is powered by an electric motor and by a four strokes four cylinders diesel engine in the second part. The numerical results of the dynamic responses of the system come to confirm the significant effect of the transient regime on the dynamic behavior of a gear set, particularly in the case of engine acyclism condition. Results also confirm the influence of the magnet number by AMBs on the dynamic behavior of the system. Indeed, vibrations were more important in the case of gear reducer supported by AMBs with four magnets.

Keywords: motor, stiffness, gear, acyclism, fluctuation, torque

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Authors: Zhemi Xu, Dewei Chu, Sean Li

Abstract:

Well self-assembled pure and Mn-doped SnO2 nanocubes were synthesized by interface thermodynamic method, which is ideal for highly homogeneous large scale thin film deposition on flexible substrates for various electric devices. Mn-doped SnO2 shows very good resistive switching with high On/Off ratio (over 103), endurance and retention characteristics. More important, the resistive state can be tuned by multi-layer fabrication by alternate pure SnO2 and Mn-doped SnO2 nanocube layer, which improved the memory capacity of resistive switching effectively. Thus, such a method provides transparent, multi-level resistive switching for next generation non-volatile memory applications.

Keywords: metal oxides, self-assembly nanoparticles, multi-level resistive switching, multi-layer thin film

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Authors: Crista Arangala

Abstract:

Light switching games are both popular and well studied. This paper introduces a cellular automata called Langton’s turmite to several different light switching scenarios and discusses when Langton’s turmite can solve these games.

Keywords: cellular automata, lights out, alien tiles, chaos, Langton's Turmite

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Authors: Jae-Woo Kim, Kyung-Jung Lee, Hyun-Sik Ahn

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This paper presents a design methodology for the motor driven automotive subsystems with the consideration of the functional safety. There are many such modules in vehicles which use DC/AC motors for an electronic throttle control system, a motor driven power steering, a motor driven seat belt systems and for HVAC systems. The functional safety for the automotive electrical and electronic parts are standardized as ISO 26262, but the development procedure is very complex to be followed. We focus on the functional safe motor controller design process and show the designed motor controller hardware satisfies the required safety integrity level by using metric calculations with the safety mechanism.

Keywords: AUTOSAR, MDPS, Simulink, software component

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Authors: Yasunori Kobori, Futoshi Fukaya, Takuya Arafune, Nobukazu Tsukiji, Nobukazu Takai, Haruo Kobayashi

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This paper proposes an EMI spread spectrum technique to enable to set notch frequencies using pulse coding method for DC-DC switching converters of communication equipment. The notches in the spectrum of the switching pulses appear at the frequencies obtained from empirically derived equations with the proposed spread spectrum technique using the pulse coding methods, the PWM (Pulse Width Modulation) coding or the PCM (Pulse Cycle Modulation) coding. This technique would be useful for the switching converters in the communication equipment which receives standard radio waves, without being affected by noise from the switching converters. In our proposed technique, the notch frequencies in the spectrum depend on the pulse coding method. We have investigated this technique to apply to the switching converters and found that there is good relationship agreement between the notch frequencies and the empirical equations. The notch frequencies with the PWM coding is equal to the equation F=k/(WL-WS). With the PCM coding, that is equal to the equation F=k/(TL-TS).

Keywords: notch frequency, pulse coding, spread spectrum, switching converter

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Authors: Won Jung, Wan Emri

Abstract:

Ferrite magnet is widely used in many automotive components such as motors and alternators. Magnets used inside the components must be in good quality to ensure the high level of performance. The purpose of this study is to design input parameters that optimize the ferrite magnet production process to ensure the quality and reliability of manufactured products. Design of Experiments (DOE) and Statistical Process Control (SPC) are used as mutual supplementations to optimize the process. DOE and SPC are quality tools being used in the industry to monitor and improve the manufacturing process condition. These tools are practically used to maintain the process on target and within the limits of natural variation. A mixed Taguchi method is utilized for optimization purpose as a part of DOE analysis. SPC with proportion data is applied to assess the output parameters to determine the optimal operating conditions. An example of case involving the monitoring and optimization of ferrite magnet process was presented to demonstrate the effectiveness of this approach. Through the utilization of these tools, reliable magnets can be produced by following the step by step procedures of proposed framework. One of the main contributions of this study was producing the crack free magnets by applying the proposed parameter design.

Keywords: ferrite magnet, crack, reliability, process optimization, Taguchi method

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Authors: Heiko Weiß, Andreas Meister, Christoph Ament, Nils Dreifke

Abstract:

Linear actuators are deployed in a wide range of applications. This paper presents the modeling and system identification of a variable excited linear direct drive (LDD). The LDD is designed based on linear hybrid stepper technology exhibiting the characteristic tooth structure of mover and stator. A three-phase topology provides the thrust force caused by alternating strengthening and weakening of the flux of the legs. To achieve best possible synchronous operation, the phases are commutated sinusoidal. Despite the fact that these LDDs provide high dynamics and drive forces, noise emission limits their operation in calm workspaces. To overcome this drawback an additional excitation of the magnetic circuit is introduced to LDD using additional enabling coils instead of permanent magnets. The new degree of freedom can be used to reduce force variations and related noise by varying the excitation flux that is usually generated by permanent magnets. Hence, an identified simulation model is necessary to analyze the effects of this modification. Especially the force variations must be modeled well in order to reduce them sufficiently. The model can be divided into three parts: the current dynamics, the mechanics and the force functions. These subsystems are described with differential equations or nonlinear analytic functions, respectively. Ordinary nonlinear differential equations are derived and transformed into state space representation. Experiments have been carried out on a test rig to identify the system parameters of the complete model. Static and dynamic simulation based optimizations are utilized for identification. The results are verified in time and frequency domain. Finally, the identified model provides a basis for later design of control strategies to reduce existing force variations.

Keywords: force variations, linear direct drive, modeling and system identification, variable excitation flux

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Authors: Omotayo Olalere

Abstract:

The relevance of code-switching for intercultural communication through literary translation cannot be overemphasized. The translation of code-switching and its implications for translations studies have been studied in the context of African literature. In these cases, code-switching was examined in the more general terms of its usage in source text and not particularly in Ngugi’s novels and its translations. In addition, the functions of translation and code-switching in the lyrics of some popular African songs have been studied, but this study is related more with oral performance than with written literature. As such, little has been done on the German translation of code-switching in African works. This study intends to fill this lacuna by examining the concept of code-switching in the German translations in Ngugi’s Petals of Blood. The aim is to highlight the significance of code-switching as a phenomenon in this African (Ngugi’s) novel written in English and to also focus on its representation in the two German translations. The target texts to be used are Verbrannte Blueten and Land der flammenden Blueten. “Abrogration“ as a concept will play an important role in the analysis of the data. Findings will show that the ideology of a translator plays a huge role in representing the concept of “abrogration” in the translation of code-switching in the selected source text. The study will contribute to knowledge in translation studies by bringing to limelight the need to foreground aspects of language contact in translation theory and practice, particularly in the African context. Relevant translation theories adopted for the study include Bandia’s (2008) postcolonial theory of translation and Snell-Hornby”s (1988) cultural translation theory.

Keywords: code switching, german translation, ngugi wa thiong’o, petals of blood

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Authors: Bachir Belmadani, Rachid Taleb, Zinelaabidine Boudjema, Adil Yahdou

Abstract:

Carrier-based methods have been used widely for switching of multilevel inverters due to their simplicity, flexibility and reduced computational requirements compared to space vector modulation (SVM). This paper focuses on Multicarrier Sinusoidal Pulse Width Modulation (MCSPWM) strategy for the three phase Five-Level Flying Capacitor Inverter (5LFCI). The inverter is simulated for Induction Motor (IM) load and Total Harmonic Distortion (THD) for output waveforms is observed for different controlling schemes.

Keywords: flying capacitor inverter, multicarrier sinusoidal pulse width modulation, space vector modulation, total harmonic distortion, induction motor

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Authors: Alireza Moghtaderi, Negin Khakpour

Abstract:

Disc Herniation is a common complication in the society and it is one of the main reasons for referring to physical medicine and rehabilitation clinics. Despite of various methods proposed for treatingthis disease, still there is disagreement on success of these methods especially in non-surgical methods, and thus current study aims at determining effect of laser beam and magnet on treatment of Intervertebral Disc Herniation. During a clinical trial study, 80 patients with Intervertebral Disc Herniation underwent a combined package of treatment including magnet, laser beam, PRP and Prolotherapy during 6 months. Average age of patients was 51.25 ± 10.7 with range of 25 – 71 years. 30 men (37.5%) and 50 women (62.5%) took part in the study. average weight of patients was 64.3 ± 7.2 with range of 49 – 79 kg. highest level of Disc Herniation was L5 – S1 with frequency of 17 cases (21.3%). Disc Herniation was severe in 30 cases before treatment, but it reduced to 3 casesafter treatment. This study indicates effect of combined treatment using non-invasive laser beam and magnet therapy on disco genic diseases and mechanical pains of spine is highly effective.

Keywords: hallux, valgus, botulinum toxin a, pain

Procedia PDF Downloads 75