African and american politics of social change Essay - 1

African and american politics of social change - Essay Example Before the era of the civil rights movement, there was no existing political or social movement in America with profound effects on the political and legal institution (Wendy, 2008). The civil right movement sought to restore the missing and the violated rights of the black people living in America as guaranteed by the fourteenth and fifteens amendment. The movement altered the relation between the state and the federal government; this is because many of the times the federal government was forced to enforce laws protecting the black people in America. The civil right movement resulted to the reemergence of the judiciary in America; this included the Supreme Court whose role was to protect the individual liberties against the majority power. Even with the incredible progress from this movement, the existing racialism and inequity between the black and the white proved difficult to eliminate. With the progress, the blacks still faced lower wages, racial discrimination, and their neighborhoods still had higher crime rates. For the younger black the movement was too mainstream to generate the intended social changes, they wanted something that could give blacks th e same opportunities as the whites both economically and socially. They felt that the movement comprised more of the white perceptions than the black perception. The head for the civil rights movement was reverend martin Luther king; he was also the head of the "southern Christian leadership conference." (Wendy, 2008) The black power movement, on the other hand, rose mainly after the civil rights movement gained momentum, this in the early 960s going on. The movement marked the turning point for the differing relationships between the blacks and the whites in the United States of America. The movement had some proactive and positive force which aimed at helping

Great Mosque of the Masjid-i-Jami Isfanhan, Iran 1088 Essay

Great Mosque of the Masjid-i-Jami Isfanhan, Iran 1088 - Essay Example The capital city was planned to be near the Friday mosque and due to Seljuks rich authoritative powers, they situated the city to the northern side of the mosque. Figure 1: The Masjid-i Jami, Isfahan According to Oleg (1990), the present mosque was rebuilt again after the destruction by earthquake and fire. It was begun by the Ghurid ruler between 1162 and1202. The mosque was constructed to bring forth the present appearance and design on how to construct mosques. This mosque has been of great concern since there has come times when the mosque was to be demolished by fire from the capture by the Tughril Beg. This capture was accompanied by riot and religious conflicts which led to the destruction of the building before it reconstruction. There were two sects in the riots which included the Hanafite and the Shafi'ite. These riots were the cause of fire which destroyed the ornamental look of the great building. During its construction the mosque was planned and the structure was to be rectangular, inner diameter of a length of 65 meters and a width of 55 meters. There are walls which are used for prayers and cover a large area with several bays. To the west are 7 bays. 4 bays are in the southern side of the mosque and 3 bays to the North West (Oleg, 1990). There are also additional four chambers to the existing bays. The mosque fits the city settings with variety of gates and entrances which allows mass entrance within a short time. The mosque covers a speculated area distinct from the city square. It fits the requirements in construction of a mosque which ensures that it should cover its special area distinct from the main city. The mosque has been the visual landmark to the city of Isfahan with large domes to the northern and the southern side of it. The other neighboring buildings are situated in a manner to show that they give space to the holy mosque. Recently, they have situated a gate to the south eastern side of the mosque. There is an inscription to the space between the building and the gate which mentions Muzaffarid sultan Mahmud who used to rule isfanhan during the year of 1358 to1374.There is another gate to the south which mentions abbas rule and this was designed in the year 1590.A northern gate which is no longer in use describes the eternal rest from Quranic Surah 76 which was constructed in 1366 (Oleg, 1990). A unique forth gate is designed which is no longer in use. It is decorated using bricks unlike the other gates which are colored and has attractive tiles. This gate explains how the mosque was reconstructed after its destruction with fire in the year 1121. The mosque court is well decorated with colored tiles of variety of colors which are; blue, yellow, white and other dark colors. This shows how the residents are united and the degree of harmonious relationships within that area. Bunce (2008) asserts that there are screens installed in the four courts on the passage way of the mosque leading to the sacred places of worship. The doomed chamber has also been constructed with an area of 15 side meters and a height of 30 meters. It was the work of architect Abul fath who did this after the fire tragedy. The southern dome carries inscription of the famous Abu Malik Shah and Nizam al-Mulk.

Immigration and Population Growth Essay Example for Free

Immigration and Population Growth Essay Immigration is when someone or people move to a country from another country. It can be due to various purposes like a student going for study, getting married to a national of another country or to take up an employment. Immigration has been known to cause population growth. Population growth is the quantifiable change of population in an area. Immigration can be defined into two that of high skilled personnel and that of low skilled personnel. Economic impacts of immigration depend on the skills of immigration. The impacts are felt by both the country from which the people are moving from and the country they are going to. Negative Impacts Immigration and population growth causes scarcity of resources. Economics standard definition is the allocation of scarce resources among competing ends. Immigration and population growth makes the task more difficult because it create more competing ends hence bad economic outcome. In other terms if there are more people living in the same land with the same amount of resources then there will be fewer resources and land available per person thus less wealth. There is also overburdening on the infrastructure talk of roads, social amenities like water, hospital beds and others. They existing facilities cannot cope with the increasing population growth before we put into consideration immigration (Holzer, 2005). Immigration and population growth cause wages decrease, this is due to increased labor supply. An increase in labor supply relative to capital supply and supply of natural resources will in a free labor market cause wages to fall. Unemployment is the other major impact of immigration; the local residents miss jobs to the immigrants who come to their country. These create more risk of unemployment. Shortage of affordable housing, this may lead to people living from hand to mouth due to increased cost of living. It in turn reduces chances of investments. Most of the income goes to up keep hence little savings and investment. Environmental degradation due to the huge population growth results to massive loss of biodiversity and wide spread degradation of the landscape. This leads to salinity of t he soil and topsoil erosion this have adverse effects on the productivity of the nation. All these have impacts on the economy in that no people can work while hungry and food is a key element of economic development. If reduced it causes a decline in the work output hence on income of a nation (Nilsson, 2005). Positive Impacts Immigration and population growth produce increased and cheap labor. Many business and public service make use of the skills and hard work of immigrants. Immigrants may never mind the amount of work they do and money they are being paid. This increases the productivity of a county in that they work for more hours and do the kind of jobs the normal civilians of a nation may not be willing to take. This increased productivity improves the income levels of a country hence the living standards are increased. The immigrants are paid declined wages due to saturation of laborers in the market hence the cost of production is low this leads to increased profit to the industries hence to the nation. Immigration increases the economy in terms of labor demand, thus creating new vacancies. Immigration improves the way of life of the residents of the country they move to; they carry out duties that are a bother to the residents like dish washing, cooking, laundry work and many more. Immigration of high skilled personnel fills the labor and skills shortages. These increase the productivity of a country. The skills also improve existing skills and train others hence labor force of a country and reduced threat of immigration (Rowthorn, 2004). Conclusion In conclusion immigration and population growth are interrelated and are beneficial though they also have negative impacts.The benefits depends on the type of skill immigrating. References: Holzer, H. J. , (2005): Economic Impacts of Immigration. Retrieved on 6th Jan, 2009 from: http://www. urban. org/UploadedPDF/900908_Holzer_111605. pdf Nilsson, T. , (2005): Negative economic impacts of immigration and population growth. Retrieved on 6th Jan, 2009 from: http://www. pc. gov. au/__data/assets/pdf_file/0005/9572/sub009. pdf Rowthorn, R. , (2004): The Economic Impact of Immigration. Retrieved on 6th Jan, 2009 from: http://www. civitas. org. uk/pdf/Rowthorn_Immigration. pdf

Control The Speed Of The DC Motor Engineering Essay

Control The Speed Of The DC Motor Engineering Essay Direct current (DC) motor is applied in a wide range of applications particularly in automation technology due to minimal voltage consumption. In the proposal DC motor plays an effective role in Hardware implementation. The main principle behind the project is to use the cascade control to run the DC motor; its one of best feedback controllers. For estimating the velocity and the armature current of the DC motor with 24 volts and a dsPIC Microcontroller is programmed .The above all operation is done in a closed control loop function. Table of Contents 1.2 Objective 2. Specific Aims of the project Chapter 1 1. Introduction 1.1 Background Brushed DC Motor DC motor model Digital control of dc motor Advantages of dc with respect to speed control Analogue control of dc motor 2.1 ds PIC dsPIC30f 3010 2.2 MPLAB IDE 3. Design and Research Cascade control Currentloop dynamics Speed loop dynamics 3.1 Components for controlling 24v brushed Dc motor 3.1. Flexible inverted board 3.2.1 Generating PWM wave forms 3.1.2 H-Bridge converter 3.2 Software techniques used in DC motor Programming microcontroller in Flexible inverted board 4. Results and Discussion 5. Conclusion 6. Appendix List of Figures FIGURE 1: Operation of BRUSHED DC Motor FIGURE2: General block diagram of speed loop and current loop of DC Motor FIGURE3: H-bridge converter with different voltage VÃŽÂ ± VÃŽÂ ² CHAPTER 1 1. INTRODUCTION 1.1 Objective The main function of the project is to control the speed of the DC Motor using a dsPIC30f3010 microcontroller. For that implement a separate hardware to satisfy the main function of the project. 1.2 Specific Aim of the project In order to achieve the main core of the project, construct Hardware for controlling the speed control of DC motor. The main hardware requirements are ds PIC microcontroller ICD interface connector for system interface DC power supply MOSFET Current sensors The above components are required to construct a hardware called Flexible Inverted Board [4]. 1.3 OUTLINE OF PROJECT Step1 In this paper a flexible inverted board is constructed with the series of hardware components Step2 Then communicate the Flexible inverted board with system using MPLAB IDE software with ICD-3 interface [4].the language used in the MPLAB software is C-language. Step3 The speed loop and the current loop are the two important functions for controlling the speed of the Dc motor. In our project the key point is to control both the loops by C-programming language using MPLAB ICD-3. The speed loop of the microcontroller is called speed controller and the current loop of the microcontroller is called current controller. CHAPTER 2 THEORITICAL TECHNIQUES AND THEIR REVIEWS 2 Background 2.1 Brushed DC Motor In automotive industries DC motor is used widely in fuel pump control, electronic steering control, engine control and electric vehicle control [6]for its cost effective and it is used in many applications like pulp and paper industries, fan pumps, press, winder motors [2],home appliances, washers, dryers and compressors[6] are some of the best examples. DC motor is one of the important hardware employed in this paper, it consists of a rotor and stator, and the parts are placed in a permanent magnetic field. Commutator and brush are placed in between the rotor and stator. Positioning the brush at a particular direction in the rotor is classified into some categories and they are radial, trailling or leading [3] positions. When the rotor rotates the commutator and carbon brush interface at a point, which produces an enormous amount of magnetic field from the brush of the motor and it produces current to the armature winding of the Dc motor. FIGURE 1: Operation of BRUSHED DC Motor[a] 2.2 DC Motor model [8] Each motor will have different specification and requirements. According to motor requirements and details the model can be designed. The aim of motor model, deals with controlling the applied voltage of both speed and current. The basic model for a Dc Motor is shown below FIGURE2: DC Motor model The above diagram is a simple RL circuit. RL circuit is called resistance inductance circuit and a 24v DC Motor. All these components combine to form RL circuit. Now the derivation part of the RL circuit is explained below T (t) = J w is the Angular velocity J is the moment of inertia B is the friction T is the armature Torque T (t) = (t) is the Torque constant is Armature current According to Kirchhoffs law (t) (t) = (t) + and are the inductance and resistance for the armature current (ia) The electromotive of the motor can be determined by multiplying the back emf with speed The relationship for the electromotive force is shown below (t) = The state model for any DC motor using ia and w (speed) is mentioned below. = + 2.3 ds PIC -microchip ds PIC stands for Programmable Interface Controller or programmable intelligent computer, which act as an important controlling unit for entire system. The main objective of this project is to make the ds PIC to generate 6PWM waveform. In an ideal condition the waveform from the pulse width modulation can control the H-bridge converter. It not only serves as an interface controllers but also plays a role of a programmable logic controller (PLC). [16,20] ds pic has a memory of 16bit microcontroller that has two major functions. Firstly it can act as a software part serving software functions and the other is a hardware part serving hardware functions. The input signals that are attain from the feedback serve system are received by the software part which in turn utilizes the codes that are written on the chip on C language to analyze the input and operate the hardware. Finally the software makes sure the hardware runs based on the software functions to gain the required output. [18, 20] Our project concentrated on working experiments that were run at lab conditions. Since a couple of systems have certain differences from the stimulation that have been run in real conditions compared to ideal conditions. This in turn is the working of the microcontroller. dsPIC30F 3010, 2010 4011 and 3012 are the series of chips that have been available in the Lab. The letter F in ds PIC30F and such chip states that the chip contains flash memory. The reason for considering this flash memory product is because 30F has an ex-ordinary performance when compared to EPROM (Erasable Programmable Read-Only Memory) and one time programmable chips (OTP). This has been a major requirement for the running of this project to get the required output. 16-bit modified Harvard architecture has been added to the CPU containing ds PIC30F for utilizing the data and upgrading the set of guide lines for running digital signal processing (DSP) [14]. There is a lengthy flexible opcode field which has been installed in the CPU that has a 24 bit wide user programmer memory area and the total addressing speed can go up to 4MÃÆ'-24 bit. This programming model has sixteen 16bit working registers in ds PIC30F chip. There are two classes of introduction controlling unit that have been integrated and used for execution they are integrated and used for execution [2]. 2.3.1 dsPIC30F 3010 This section is about the pin configuration and the components available in dsPIC30F3010 microcontroller. Normally the memory allocation in dsPIC30F 3010 can classified in to three categories they are SRAM in Bytes EEPROM in Bytes Programmable memory in Bytes/instruction 2.3.1.1 SRAM SRAM stands for static RAM (Random Access Memory). According to the tabulation shown below the data limit for static RAM should not exceed 1024 bytes. The memory in the function can classified in two types they are X Data RAM Y Data RAM The static RAM uses X -RAM and Y_RAM for storing datas. 2.3.1.2EEPROM The memory allocation for EEPROM is same as static RAM. In read only memory one of the important types of ROM used to store memory is EEPROM. The main function of this ROM is based on two parameters they are endurance and retention [2]. Endurance is to retain the data even after the ROM fails. Therefore the data cant be deleted at any instant. Time period is required to store data that is taken care by retention [2]. 2.3.1.3Program memory In a particular program ds PIC30f microcontroller has a separate memory allocation for storing both the address and data. The memory limit for the program memory is 24K. program address space anda data address space TABLE 1: Tabulation for memory allocation in ds PIC30f3010 The pin configuration of dsPIC30f3010 is described below FIGURE 3: Pin configuration of dsPIC30F 3010[2] Pin descriptions (PWM1L and PWM1H), (PWM2L and PWM2H) (PWM3L and PWM3H) [2] these are six different types PWM channels used in the pin configuration. In which each PWM pair generates three duty cycles with one high output (H) and one low output (L). INT0, INT1INT2 are the interrupt buffers used in the PIC. VSS and VDD [2] are the supply voltage and ground in the PIC controller. U1RX U1TX, U1ARX U1ATX [2] are the series of pins used for communicating PIC microcontroller with PC, in other system interface operation can be done by UART function. In that RX stands for receiver and TX stands for transmitter. The above pin function plays an important in our project. CHAPTER 3 METHODOLOGY 3.1 Components for controlling 24v brushed Dc motor Since the project is fully based on hard ware so many components are available and how they work in that operation. 3.1.1Cascade control operation in Dc Motor: The below operation is done by using Double cascaded layout, it consists of two loops they are current controller with current reference and speed controller with speed reference [5] as shown in . FIGURE4: General block diagram of speed loop and current loop of DC Motor [b] The current loop is covered by the speed loop, in the block diagram it has the two circles inner circle is called inner loop and the outer circle is called outer loop since the inner circle operation is always quicker than the outer circle. In other words inner circle performance is multiple of ten times quicker than the remaining one. The cascade control principle is mainly used in our project to maintain the speed of the motor at a constant level and the current loop in the cascade control is the armature current and it is otherwise called as torque. Sometimes armature current may exceed the limit to avoid this situation in cascade control, it has limiter, and the main function of the limiter is to limit the values of the armature current. For example To limit the armature current to 64volt i.e. 1 ampere. So that the armature wont exceed those limits since the limiter is available in cascade control. The speed controller in the cascade control used to produce demand current ia*. Th e motor runs to overcome the demand current values. The demand current value will always higher than the normal current values. So that the speed motor gradually increases. PI controller(proportional Integral controller) Current controller Speed controller The above all components construct a cascade controller and the function each component is described below 3.1.1.1PI controller (proportional and integral controller) In cascade controller function various controllers are used for detecting the speed and control of the motor, but PI controller is recommended as high efficient controller because it consist to constant gain Kip and Kid. By manually tuning the gain of both Kii and Kpi will reduce the steady state error and the stability of the system will be increased. In recent survey more than 70% cascade controller used PI controller for controlling the speed control DC Motor. In order to reduce the steady state error in the closed loop system, gradually increase the proportional gain constant Kp. As the gain of the Kp increases the steady state error in the system decreases. But the stability of the system will not be stable. To make the system stable, integral term Ki is introduced in the system. When both the proportional and integral term sum each other to reduce the steady state error and make the system stable .the above two functions can be done simultaneously in the PI controller. The math ematical expression for PI controller is explained below. FIGURE 5: PI controller of a closed loop function [1] Kp-proportional gain Ki-Intergral gain Y- Output of the PI controller Err-Error in the PI controller At the beginning error (Err) will pass through both Kp and Ki. For proportional gain the output is Kp Err y1= Kp Err eqn1 [1] y2 = eqn 2 [1] y = y1 + y2 eqn 3 [1] eqn 4 [1] The key point in this PI controller is the error Err in intergral gain Ki will be integrated. so that the steady error will be reduced and the system will be stable. 3.1.1.2Current controller The current controller in the closed loop functions of the cascade control. The current loop is also called as current controller. It is used to protect cascade circuit from damage. The main function of the cascade function is to control the speed. Before controlling the speed the current of the controller should be controlled. The current obtained from the closed loop function is from armature circuit of the DC Motor [7].the input in the current controller is the back emf (ia*). Power converter is mainly used to improve the control in the system. It has high switching frequency, since the power converter in the current loop is very quick. The output of the converter is armature voltage (Va). (-E) is the disturbance occurred in the current loop, in order avoid the disturbance -E ia ia* RL CIRCUITT Power Converter PI FIGURE 6: Functional block diagram of Current controller The disturbance is added along with RL circuit, and the equation is shown below Va = (S La + Ra) ia + E The function of the RL circuit is reduce complexity Va is Armature voltage. ia is armature current (trying to control) Ra is Armature resistance E is Disturbance RL = 1/(S La + Ra) Current loop is carried out by transmitting the from ia(armature current) to ia*(demand armature current). As quick as possible without making the over shoot getting so high. If the over shoot is high it creates problem to the converter. Similarly when the gain values (Kp and Ki) increases in PI controller the over shoot value reduces, but the same time there is more amount of oscillation which may affect the system. Care should be taken in choosing both Kp and Ki values. ts ia ia** FIGURE 7: graph for armature current vs settling time ia Armature current ia* Demand armature current ts Settling time 3.1.2 Flexible inverted board The major hardware has been designed and implemented as Flexible inverted board. It consists of many components they are dsPIC30F3010 microcontroller, H-bridge converter and dc motor. The functions of these hardware components are explained earlier. The above all operation is implemented in a single hard ware called flexible inverted board. FIGURE 8: Functional block diagram of Flexible inverted board 3.1.2.1 IR2130 gate drive circuit: There are three input signal generator blocks which are capable of providing two outputs each gives the inputs to the six output drivers. L1, L2 and L3 are signal generators which drive precisely the three low-side output drivers although H1, H2 and H3 signal generators must be level shifted before it is fed to the high-side output drivers. The floating points of the driver, gate charge requirements of the power switch and the maximum power switch ON times receives power from three bootstrap capacitors C1, C2 and C3. Bootstrap capacitors also feed supply to the internal floating driver current. Once these energy requirements are met there must be considerable amount of charge still on the 8.3V nominal to prevent stopping. D7, D8 and D9 should be super-fast. VCC level seen by an under-voltage detector circuit gives an input to outlaw six outputs of the signal generator circuits. Current sensor R1 derives the ITRIP signal in the main power circuit of the motor when it is segregated with a 0.5 volt reference to outlaw the six signal generator outputs. ITRIP inputs sets up a fault logic circuit which in turn gives open drain TTL output for system gesture. FIGURE 9: Circuit diagram for IR2130 gate drive circuit 3.1.2.2Trim port function with PWM Trim port are small in size and they are very small in size .it is mainly used in many PCB construction board since its occupies less space. The trim port act like a potentiometer and it is otherwise called as trimmer [ ]. By tuning the trim port, resistance value can be minimized or maximized. For example if a 50ohm resistance can be tuned by trim port from 0 50. The two leg of H-bridge converter produce two pulse wave form one with low output (1L) and another one with high output (1H). The duty ratio of the PWM wave form can adjust using trim port. 3.1.2.3DC MOTOR ENCLOSED WITH A ENCODER The best methods of calculating the speed of the DC motor is using optical encoder method. It consists of a disk, Light Emitting Diode (LED) and optical sensor [6]. The disk is fitted with the rotor, as the rotor rotates the disk starts spinning along with the rotor and it is placed in between the LED source and the light sensor. Once the rotation starts the disk passes through the LED source and the optical sensor gets started, from which the speed of the motor can be calculated because the optical sensor acts like a tachometer. In other words the encoder in the DC motor is otherwise called as speed detecting sensors. [6] 3.1.2.4 H-Bridge converter DC motor runs differential speed, but the applied voltage of the motor varies at every interval of time. Since the voltage is directly proportional speed, as the voltage increases the speed of the motor also increases. Speed can be calculated by tachometer which is in build in the DC motors, the applied voltage can be supplied and controlled by a converter called h-bridge converter. GD GD Gate Drive Circuit FIGURE 10: H-bridge converter with different voltage VÃŽÂ ± VÃŽÂ ²[c] In this H-bridge circuit it produces two unipolar pulse width modulations because it has two leg inverter. Effective modulation takes place only in the first half of the inverter. As a result two variable voltages are generated on either side of the armature winding. In H-bridge, modulation index is represented as (+mi) and the reciprocal of modulation index is represent as (-mi).the motor in our project actually experiencing two pulse width. Both the pulses are inversely proportional to each other producing a unipolar PWM. The two legs in the converter are called the switching signals or switching frequency. Bigger converter relatively has lower frequency and smaller converter has higher frequency. If the frequency in the leg1 is high in contrast the frequency in the leg2 will be low. In our project consider VÃŽÂ ± and VÃŽÂ ² are the switching channels of the H- bridge converter . they are inversely proportional to each other. The carrier signal is called the input frequency . the carrier frequency used in our project is 10khz. According to the carrier frequency the time period of VÃŽÂ ± and VÃŽÂ ² differs. In C coding VÃŽÂ ± and VÃŽÂ ² is mentioned as PDC1and PDC2 from the below graph FIGURE 11 graphical representation of PWM signals in H- Bridge converter. The output voltage of the h-bridge converter can be obtained both negative and positive voltage distribution [1]. Pulse width modulation in the h-bridge converter helps to control the armature circuit of the DC motor [1]. Maximum armature current (torque) can be obtained by comparing time constant of both field winding and the armature winding [1]. Since the motor is connected directly to the field windings supply voltage in the field winding is more when compared with the armature winding. To maintain equal time constant in both field and armature winding [1], the applied voltage in the armature winding should be increased, as the armature current increases the torque output is maximized [1]. 3.1.3 Generating PWM wave forms As the torque output gets maximized, pulse width modulation is introduced in the H-bridge system to avoid the disturbance in the armature current.it can be done by increasing the frequency level of the H-bridge converter at a higher range. As the torque output gets maximized, pulse width modulation is introduced in the H-bridge system to avoid the disturbance in the armature current.it can be done by increasing the frequency level of the H-bridge converter at a higher range. FIGURE 12: Diagrammatic representation of the pulse width modulation is shown below [6] The below specification is referred from [6] Ton Time is ON (applied voltage) Toff Time OFF (applied voltage) T Time period. Duty cycle =. The average voltage of the DC motor can be shown in an equation below Average = Duty cycle ÃÆ'- Vin [6] When the motor is running at a constant speed the back emf of the motor is also remain constant. As the back emf remain the same the motor running at constant speed and the armature current (Ia) is zero. PWM is one main part that is required for the operation of cascade control. 4. Software used to drive the Motors 4.1 Programming microcontroller in Flexible inverted board using C-language In the flexible inverter board PIC microcontroller plays a major position in directing the pulse width modulation. The Ton time in the pulse width modulation (PWM) signal can be modulated or controlled by the microcontroller, as the microcontroller varies the time, the velocity of the motor changes with respect to time. The Programing language used in microcontroller is embedded C. The programming codes are downloaded in the microcontroller chip, the downloading approach can be done by a software development tool called MPLAB, this software exists in monitoring the systems, this software should be first installed in the PC, the programmers will write the codes to modulate the PI controller to acquire Applicable source from the current loop of the cascade control function. Once the codes are accepted according to the current loop [1], the programs can be downloaded in the microcontroller through universal serial bus or in circuit Debugger (ICD); ICD is a bus which interfaces PC system and the flexible inverter Board. [6] In order to program the microcontroller examine whether the hardware components are interfaced with the controller. The programming language used for programming the controller is C language. In c-language the datas are classified in to input data and output data. The microcontroller send the information in analogue signal, where the C-language wont accept analogue signals .To avoid the situation ADC converter and encoder interface are introduced in the system. ADC stands for analogue to digital converter; it converts the analogue signal in to digital signals. Then the digital signals get received by the C-program as input data. In turns c-program will send the output data to the PWM unit. UART communication system is a bidirectional so that microcontroller and PC can communicate simultaneously. UART stands for universal asynchronous receiver transmitter. The basic diagrammatic representation for system communication with C-language is shown below FIGURE 13: System communication in C Programming Language. In C-language firstly initialise all the functions required for the speed control of motor. 4.1.1Current sensor input: The current in the motor coils is one important parameter in the effective running of the motor. So it is essential to measure the value of this current. The measurement of the current is performed by using special sensors call Hall Effect Sensors. The range of the current is determined by the rating of the motor. Any over current in the motor can badly damage the motor. The Hall Effect sensors produce a voltage corresponding to the phase current. This is fed to the ADC inputs of the micro controller where it is converted into the digital signals. This is then fed into the microcontroller program. Hence the current needs to be limited within specific limits.CL1, CL2 and CL3 are the three current sensors variables used in this coding. The bit ratio of the ADC input is 10 so the input data ranges from 0 to 1023. The maximum data limit for the current sensor is 1023.so the current sensor value in the C- code is initiated as CL1 = 511; CL2 = 511; CL3 = 0; 4.1.2 Encoder input: For any speed controller, the actual speed of the rotor forms the basis for the control signals. The speed control signal can be changed only if there is an error between the actual speed of the rotor and the desired speed of the rotor. If the measured speed is less than the desired speed then the PWM pulses are varying accordingly to increase the speed. To perform this action a shaft encoder is used. The shaft encoder uses an opto-mechanical system to generate pulses. These pulses then are used to derive the speed of the rotor. A reference pulse is used as an indicator to count the pulse. This information is fed to the microcontroller, which then uses a special timing circuit that processes these encoder pulses. The motor speed to be accessed by the microcontroller needs to be stored in a variable within the micro controller code. The variable used in this program is a variable called rpm. This variable is accessed to calculate all functions related to the motor speed. 4.1.3 Pulse Width Modulation: The MOSFETs in the circuit is used as switches. These MOSFETs are switched according to a PWM. To drive these MOSFETs a gate driver circuit is required. The gate drive signal generates the voltage required for the operation of these MOSFETs. The PWM is generated by the microcontroller according to the program and is supplied to the gate drive circuit. The PWM signals are separate for each if the 3 legs of the MOSFET inverter. Each of the PWM requires a modulation index to generate the signal. These modulation indexes are stored in a register. The registers are named as PDC1, PDC2, and PDC3. These variables are very crucial in generating the PWM signals for the MOSFET drivers. Since data limit is 1023. 4.1.4 Initializing the code in C language Before performing any function in C-language, it requires an initialisation. It is important to initializing the variable of a function. Some the functions are initialized below. Init PORT () This function initialize the digital input and output port or analogue input and analogue output of the microcontroller. Init UART () It is one of pin in the microcontroller .The main function of the UART is used for bidirectional communication with PC. Since UART can able to detect the transmission speed in data transfer between the microcontroller and PC. The maximum transmission speed is around 19200.the data transfer wont exceed the limit. Init PWM ( ) The input frequency of our PWM signal is 10kHz.the time limit for the modulation index is around 0-1474.in the h-bridge converter has two legs so each leg produces a PWM signal with a maximum time limit of 0-737. Hence the Ton time of PWM signal will be in 1:1 duty ratio. Init ADC ( ) It is used to convert the analogue signals in to digital signals. In the microcontroller there are five pins reserved for the ADC inputs. During the data transmission ADC functions plays a important role in interrupting the signal. An initialisation is required for the interrupt to perform any function in C- language. Init CAPTURE ( ) The capture function is mainly used to measure the frequency and time period of the PWM wave form generated from the two legs J30 and J31 pins of the H-bridge converter InitTimer3 ( ) and InitTimer1 ( ) To set initial time in the microcontroller for the capture function and timer 1 set the starting time for the interrupt function happened in the UART communication system. Interrupts: Interrupts are occurred only during the data transfer, when the transmission speed that is the baud rate is known means the interrupts can be added to the system easily.in our project the baud rate is 19200.the main function of the interrupt is used synchronize time period of PWM with the speed loop and the current loop of the motor. In our project four different type of interrupt service routine are used. They are ISR_ADCInterput ( ) This interrupt is triggered when the ADC finishes its conversion and hence its get synchronized to the microcontroller PWM time base. From this all the application control code to be implemented in this interrupts service routine. ISR_T1Interput ( ) The various information to the PC is transferred by using the UART communication link in this interrupts service routine. All the variables that are needed to be mentioned in this routine using standard C function sprint ( ). ISR_U1RXInterput( ) Various information is transferred from the PC in to the C program. This routine concedes us to regulate the aspects of the program when it is running. ISR_IC1Interput( ) It measures the speed value from timing data that are attained in the input capture module. FIGURE 14 The connection diagram for the speed control of Dc motor is shown above CHAPTER 5 5 Results and discussion As discussed earlier the various functions of hardware components in this project, this section discusses the details regarding how the project deals with comparing and evaluating the results. Project has a series of steps; each step is assigned with different operation techniques to execute the final results. 5.1 Initial connection test between MPLAB IDE and Flexible inverted Board Initially the system needs to be interfaced using the flexible inverter board. This operation is performed by conne

Torvald Helmer of Henrik Isbens A Dolls House :: A Dolls House Essays

Torvald Helmer of Henrik Isben's A Doll's House In Henrik Isben's A Doll's House, he makes the observation that women in contemporary society posses no independent self unrestricted from the male's image of them; Isben accomplishes this through the character relationship between Torvald Helmer and his wife Nora. Henrik Isben sought to show the psychological complexity of realism underneath the surface of a typical urban bourgeoisie or professional class family. Thus in doing so, brings out the central conflict between the idealistic Torvald and this underlying theme demonstrated through Nora. Ultimately, it is because of Torvald's completely inflexible and self-righteous attitudes towards life and his moralistic values, that Nora is driven from her role of submisiveness in his game of male dominance to seek her own identity. Hel. (walking about the room). What a horrible awakening! All these eight years-she who was my joy and pride-a hypocrite, a liar-worse, worse-a criminal! The unutterable ugliness of it all! For shame! For shame! ...(62) It is only when she has found this sense of a self that she had been denying and sacrificing all these years, that she can truly begin to love others. Hel. Before all else you are a wife and a mother. Nora. I don't believe that any longer. I believe that before all else I am a reasonable human being just as you are-or, at all events, that I must try and become one. (68) This game which she had been playing with her father before, and now with the close-minded Torvald, she finally realizes, is the "Dolls House" she's been living in for all her life, never finding out who she truly is. Nora. But our home has been nothing but a playroom. I have been your doll wife, just as at home I was Papa's doll child; and here the children have been my dolls. I thought it was great fun when you played with me,

Mark Twain is a Great American Author :: Biography Biographies Essays

Mark Twain is a Great American Author In the book Huck Finn, Mark Twain not only writes about the adventures of a young boy, he depicts the struggle that people had to go through in that time period. That is just one of the reasons why some people consider Mark Twain to be the greatest American author of all time. As I was reading the book Huck Finn I started to agree more with what Mencken had to say "Put him beside Emerson, or Whitman, or Hawthorne, or even Poe; he was palpably the superior of all of them". I could really relate to lots of the ideas and emotions that sprang into Tom and Huck's heads at the time. In Huck Finn, Tom gets a group of boys together to form a little club. When I was younger I would do the same thing with friends of mine. We would act out our fantasies just like Tom and Huck did in the story. All of Huck's life he was able to live it the way that he wanted, until he had to move in with Miss Watson. But as you read you find out that every minute he is away from her he is up to his old tricks again. From going out to having a smoke with Tom, or messing up his hair so he could feel at home. You can see that he is still a little boy inside who isn't ready to grow up. Tom Sawyer is one of those type of friends that everybody has, crazy enough to get everybody's attention but smart enough to know when to stop. I read some of the things that Tom had done in the book and some of the lies he would tell and I thought "man he is crazy for doing that" but as I thought about it more it seems reasonable to a kid at that age and why wouldnt he act the way he did ? Mark Twain takes a big step to the side when he writes about one of Miss Watsons slaves. Jim is a strong black slave in about his mid-twenties. As you read about Jim and see what he's had to go through you can start to Mark Twain is a Great American Author :: Biography Biographies Essays Mark Twain is a Great American Author In the book Huck Finn, Mark Twain not only writes about the adventures of a young boy, he depicts the struggle that people had to go through in that time period. That is just one of the reasons why some people consider Mark Twain to be the greatest American author of all time. As I was reading the book Huck Finn I started to agree more with what Mencken had to say "Put him beside Emerson, or Whitman, or Hawthorne, or even Poe; he was palpably the superior of all of them". I could really relate to lots of the ideas and emotions that sprang into Tom and Huck's heads at the time. In Huck Finn, Tom gets a group of boys together to form a little club. When I was younger I would do the same thing with friends of mine. We would act out our fantasies just like Tom and Huck did in the story. All of Huck's life he was able to live it the way that he wanted, until he had to move in with Miss Watson. But as you read you find out that every minute he is away from her he is up to his old tricks again. From going out to having a smoke with Tom, or messing up his hair so he could feel at home. You can see that he is still a little boy inside who isn't ready to grow up. Tom Sawyer is one of those type of friends that everybody has, crazy enough to get everybody's attention but smart enough to know when to stop. I read some of the things that Tom had done in the book and some of the lies he would tell and I thought "man he is crazy for doing that" but as I thought about it more it seems reasonable to a kid at that age and why wouldnt he act the way he did ? Mark Twain takes a big step to the side when he writes about one of Miss Watsons slaves. Jim is a strong black slave in about his mid-twenties. As you read about Jim and see what he's had to go through you can start to

Morality and Ethics Essay

Morality and ethics are terms often used as if they have the same meaning. At other times, they are used as if they have no relationship to one another. I think most people realize ethics and morality have something to do with the concepts of good and bad. However, English is not like French, which has the Academic Fantasies acting as its linguistic jury – establishing what proper French is. English changes at the impulse of the crowded. One can bomb, and that’s bad, but if one is the bomb, and that’s good. The word â€Å"morality† has been co-opted by groups, such as the Moral Majority, making us think morality only deals with acts these religious groups think aren’t proper, or are therefore immoral. The meanings of the terms â€Å"ethics† and â€Å"morality† can be differentiated based on their origins in ancient Greek and Latin, respectively. As a result, words that come into the English language from the Greeks often have meanings that are primarily philosophical study, while the Latin-derived words imply â€Å"doing the thing. † Ethics comes from the Greek word ethos – moral character or custom. Morality comes from the Latin word moralist – custom or manner. The words both deal with the customs or the manner in which people do things. Their modern meanings relate to the way people act – either good or bad. Morality, strictly speaking, is used to refer to what we would call moral conduct or standards. Morality is looking at how good or bad our conduct is, and our standards about conduct. Ethics is used to refer to the formal study of those standards or conduct. Sometimes, one refers to the study of conduct as moral philosophy, but that is less common than just saying â€Å"ethics. † One might say that morality is ethics in action, but in the end, the two terms can be used interchangeably. The study of ethics or moral philosophy can be divided into three broad areas: descriptive, normative and analytical or met ethics. Ethics deals with such questions at all levels. Its subject consists of the fundamental issues of practical decision making, and its major concerns include the nature of ultimate value and the standards by which human actions can be judged right or wrong. The terms ethics and morality are closely related. We now often refer to ethical judgments or ethical principles where it once would have been more common to speak of moral judgments or moral principles. These applications are an extension of the meaning of ethics. Strictly speaking, however, the term refers not to morality itself but to the field of study, or branch of inquiry, that has morality as its subject matter. In this sense, ethics is equivalent to moral philosophy. Although ethics has always been viewed as a branch of philosophy, its all-embracing practical nature links it with many other areas of study, including anthropology, biology, economics, history, politics, sociology, and theology. Yet, ethics remains distinct from such disciplines because it is not a matter of factual knowledge in the way that the sciences and other branches of inquiry are. Rather, it has to do with determining the nature of normative theories and applying these sets of principles to practical moral problems. Virtually every human society has some form of myth to explain the origin of morality. In the Louvre in Paris there is a black Babylonian column with a relief showing the sun god Shamash presenting the code of laws to Hammurabi. The Old Testament account of God giving the Ten Commandments to Moses on Mt. Sinai might be considered another example. In Plato’s Protagoras there is an avowedly mythical account of how Zeus took pity on the wretched humans, who, living in small groups and with insufficient teeth, weak claws, and lack of speed, were no match for the other beasts. To make up for these deficiencies, Zeus gave humans a moral sense and the capacity for law and justice, so that they could live in larger communities and cooperate with one another. There is some difficulty, already known to Plato, with the view that morality was created by a divine power. In his dialogue Euthyphro, Plato considered the suggestion that it is divine approval that makes an action good. Plato pointed out that if this were the case, we could not say that the gods approve of the actions because the actions are good. Why then do the gods approve of these actions rather than others? Is their approval entirely capricious? Plato considered this impossible and so held that there must be some standards of right or wrong that are independent of the likes and dislikes of the gods. Modern philosophers have generally accepted Plato’s argument because the alternative implies that if the gods had happened to approve of torturing children and to disapprove of helping one’s neighbors, then torture would have been good and neighborliness bad. That morality should be invested with all the mystery and power of divine origin is not surprising. Nothing else could provide such strong reasons for accepting the moral law. By attributing a divine origin to morality, the priesthood became its interpreter and guardian, and thereby secured for itself a power that it would not readily abandon. This link between morality and religion has been so firmly forged that it is still sometimes asserted that there can be no morality without religion. According to this view, ethics ceases to be an independent field of study. It becomes, instead, moral theology.