Skeletal System Research Paper Example | Topics and Well Written Essays - 250 words

Skeletal System - Research Paper Example 2. Differentiate between the processes of bone growth by length and width. 3. After a recent visit to her doctor, Gina was told that she has early signs of osteoporosis. The doctor recommended she participate in low impact exercises to strengthen her bones. Based on your reading, define osteoporosis and explain how low impact exercises will improve Gina's bone density and strength. 4. Explain the function of bone marrow and its importance in individuals with blood loss or decreased efficiency. 5. George is going in for laser treatment to his lower back. George has been experiencing pain running down his right leg for the past few weeks and has forced him to stay home from work for the past week. He hurt his back when he twisted and bent to the side to pick up some heavy lumber. Based on the case information, describe the injury that George sustained and the structures involved. 1. In cases such as car crashed, potential injuries that are likely to occur include back injury, knee dama ge, whiplash, brain and head trauma, broken or fractured ribs and spinal cord injury. In cases such as car crashes, the body is most probable to suffer trauma (Caldwell D.S., 2011). Trauma varies in intensity, ranging from serious burns or traffic accidents (Hall J et al 1995).

School segregation Essay Example for Free

School segregation Essay As I walk through our schools and communit people living and socializing where they feel it is most affordable and comfortable. Individuals in society live to their own standards, producing their own living conditions. I was interested in writing about how the racial segregation came about in America at first. However, I noticed that the topic is too broad and after reading several articles regarding racial segregation in America, I noticed how interesting that this racial issue have caused an effect to the education system around the states. Schools around the United States are getting more and more heavily segregated by different races which could also cause an imbalance of income groups. For example, in New York City, we can see that the majority of the black people or minorities would prefer to live in areas such as Harlem or Brooklyn which relatively have a lower cost of living compared to Manhattan or downtown. Educational segregation was once widely viewed as a result of white racism. Roberts v. Boston was the first case to challenge segregation in public schools. In  this case, five-year-old Sarah Roberts was barred from her local primary school because she was black, and was forced to travel a great distance to get to school every morning. Her father sued the city of Boston to allow his daughter to attend a school in their neighborhood. The case was heard by the Massachusetts Supreme Judicial Court on Dec. 4, 1849. The following April, the court ruled that school segregation was constitutional. However, the fight to end public school segregation did not end there. This example shows that educational segregation had been  around for a long time and it is not getting any better. Besides that, it is known that public schools in one of the most racially diverse states in the country, New York are the most highly segregated, with minority and poor students increasingly isolated by race and class, according to a new report released by a civil rights policy group at the University of California, Los Angeles. The proportion of Latino and Asian students in the state of New York nearly doubled from 1989 to 2010, but their exposure to white students in public schools decreased during that time, the report said. And as minority student populations increased, the proportion of low-income students in those minority-majority public schools also rose, making the schools â€Å"severely segregated† in terms of both race and class, according to the report. This means that the children who most depend on the public schools for any chance in life are concentrated in schools struggling with all the dimensions of family and neighborhood poverty and isolation. Imagine how unfair the opportunities that these students could have gotten. Based on the Department of Education statistics looking at public  school enrollment in New York City within the past 20 years, it is found that while nearly 50 percent of public school students in New York state are considered low-income, black and Latino students tend to enroll at schools where about 70 percent of students are low-income, while white students attend schools where 30 percent of students are low-income. What’s more, the proportion of black students attending public schools considered â€Å"intensely segregated† which is define as having a student body that’s less than 10 percent white is on the rise. For example,  the country’s largest school system which is in New York City has 60 percent of the state’s black public school students attend school in the five boroughs, along with two-thirds of the state’s Asian and Latino students but only 10 percent of New York state’s white students. So, how did all this segregation came about? The changing demographics in the state paired with a lack of diversity-focused policies which include subpar transportation systems for students and restrictive admissions standards is one of the factor that caused the increasing segregation of public school students. Integration problems also started with parents choosing where to live. They are most definitely influenced by the perception that whites wont treat them equally, whether that perception is real or not, and whether its rooted in formal education or pop culture. Basically this residential segregation is defined as â€Å"the physical separation of cultural groups based on residence and housing,† which sorts different populations into their own sectors. The main â€Å"issue† of residential segregation is the wealthier white community not allowing blacks to move into their neighborhoods, which is  true in some atypical cases. However, it doesn’t make sense why anyone would want to live in a neighborhood where they feel threatened or unwelcome, pertaining to the minuscule amount of neighborhoods that still practice racism. Some real estate companies are assumed to sell certain properties to individuals based on race. Yet, this point is not valid. Buyers give real estate agents a budget for what they can afford and this is the factor that limits them to specific neighborhoods. Statistically, minorities’ average income is less than that of a white person. Most of  minorities such as Asian are still struggling to get a high paid job compared to the white people . Therefore, they can only afford certain size houses in particular neighborhoods. For example, in New York City, the Chinese people tend to live in Flushing and Chinatown where houses and the cost of living are relatively cheaper than other parts of the cities. In reality, people living where they can afford causes this so called residential segregation which then leads to our problem of discussion, the education segregation. I would like to research deeper on how racial inequality in America causes  education segregation in our society today and also why are people still stuck to this norm. I had read many interesting articles regarding education segregation which can further improve my knowledge on how economical imbalance can be connected to education segregation as well as residential segregation around the states. I will also get a better understanding on how education segregation causes inequality to the people and why is this issue still going on after so much efforts had been taken via the article â€Å"Still Separate, Still Unequal† by Jonathan Kozol. This racial segregation in education has to be solved efficiently really soon before it gets even worst. The United States of America is blessed with people from all over the world and is one of the richest country in terms of diversity and cultures. We should be grateful that America is able to bring together people of different races and therefore should try the best to promote equality among everyone and also prevent stereotyping. It is important that the government try to think of a more effective way for city planning, housing development, and even school district demographics to ensure that America’s education.

Short Duration Voltage Variations Engineering Essay

Short Duration Voltage Variations Engineering Essay For long time, the main concern of consumers in power system was the reliability of supply which means that the continuity of electricity. However, it is not only the reliability that consumers want these days, quality of electricity supply is also very important for consumers. The term, electric power quality, broadly refers to maintaining a nearly sinusoidal bus voltage at specified magnitude and frequency in an uninterrupted manner from the reliability point of view. For a well-designed generating plant, which generates voltages almost perfectly sinusoidal at rated magnitude and frequency, power quality problems start with transmission system and stay applicable until end users in distribution system. The power quality in power system are categorized as temporary phenomena and steady state phenomena The power qualities are characterized in the power system by different terms suggested by Padiyar, K.R.,(2007) under these two categorizes are summarized as follows: 1.2. TEMPORARY PHENOMENA Transients: Transients are short-duration, high-amplitude pulses superimposed on a normal voltage waveform. They can vary widely from twice the normal voltage to several thousand volts and last from less than a microsecond up to a few hundredths of a second. Transients can be classified as impulsive transients and oscillatory transients. Impulse transients are mainly caused by the impact of lightning strikes to the power system. The typical causes of oscillatory transients are capacitor or transformer energization and converter switching. While impulsive transient is a sudden and has non-power frequency change in voltage and current with a fast rise and decaying time, oscillatory transient has one or more sinusoidal components with frequencies in the range from power frequency (50Hz) to 500 kHz and decays in time. Short Duration Voltage Variations: Short Duration Voltage Variations are defined as the variations in the supply voltage for durations not exceeding one minute and caused by faults, energization of large loads that having large inrush currents or rapidly varying large reactive power demands of the loads. These are further classified as voltage sags, voltage swells and interruption. Long Duration Voltage Variations: Long Duration Voltage Variations are defined as the rms variations in the supply voltage at fundamental frequency for exceeding one minute, such as overvoltage, under voltage and sustained interruption. The causes of overvoltage (or under voltage) may be the switching off (or on) of a large load having poor power factor, or the energization of a large capacitor bank or reactors. Voltage Unbalance: Voltage Unbalance is the condition in which three phase voltages of the supply are not equal in magnitude and may not be equally displaced in time. The primary causes are the single phase loads, open circuit in any one phase of a balanced 3phase loads and unequal loads connected in each phase of a poly phase systems. Waveform Distortion: Waveform Distortion is defined as steady-state deviation in the voltage or current waveform from an ideal sine wave. These distortions are classified as dc-offset, harmonics and notching. The causes of dc offsets in power systems are geomagnetic disturbances, especially at higher altitudes and half-wave rectifications. These may increase the peak value of the flux in the transformer, pushing it into saturation and resulting in heating in the transformer. Power electronics equipments like UPS, adjustable speed drives injects harmonics in the power systems. Notching is a periodic voltage distortion due to the operation of power converters when current commutates from one phase to another. Voltage Fluctuations: Voltage Fluctuations are defined as the rapid, systematic and random variations in the supply voltage. This is also called as Voltage Flicker and is caused by rapid and large variations in current magnitude of loads having poor power factor such as arc furnaces. These large variations in load current causes severe dip in the supply voltage unless the supply bus is very stiff. Power Frequency Variations: Power Frequency Variations are the variations that are caused by rapid changes in the load connected to the system, such as the operation of draglines connected to a comparatively low inertia system. Since the frequency is directly related to rotational speeds of the generators, large variations in power frequency may reduce the life span of turbine blades on the shaft connected to the generator. Although these above terms are not new, customer awareness on power quality has increased. In recent times, power quality issues and custom solutions have generated tremendous amount of interest among power system authorities and engineers. International Electro technical Commission (IEC) and Institute of Electrical and Electronics Engineers (IEEE) have proposed various standards on power quality. This led to more stringent regulations and limits imposed by electricity authorities although they differ from one country to another in a limited extend. Although terms of power quality are valid for transmission and distribution systems, their approach to power quality has different concerns. An engineer of transmission system deals with the control of active and reactive power flow in order to maximize both the loading capability and stability limits of the transmission system. On the other hand, an engineer of distribution system deals with load compensation either by means of individua l or group compensation in order to maintain power quality for each load in the distribution system (Sankaran.C, 2002, John J.Paserba et al, 2000). The utilization of power electronic based power conditioning devices brought the solution for these power quality issues in distribution system. 1.2 FACTS CONTROLLERS In recent years, many multinational software companies and automobile industries established their units in India. In turn, it initiates many other small industries to supply their needs. The growth of these industries is found to be very fast and it pollutes the power system by injecting harmonics into it. These industries need electrical power for its operation. Establishing new power generation unit is not so easy in India due to the initial cost. In addition it has many constraints like fuel constraints, political constraints, economical constraints and technological constraints. This makes to think an alternate solution for the scarcity of power by improving the quality of existing power. Reducing the wastages and improving the quality of available power is equivalent to generation of power. To improve the reliability and deliver energy at the lowest possible cost with improved power quality, power supply industries require increased flexibility in the transmission and in the di stribution systems. The power industries are handling these challenges with the power electronics based technology of Flexible AC Transmission systems (FACTS). This term covers the whole family of power electronic controllers, some of which may have achieved maturity within the industries, while some others are yet in the design stage. As Higorani et al (1999) described the various VSC based FACTS controllers are available for power quality improvement. FACTs has been defined by the IEEE as follows. Power electronics based system and other static equipment that provide control of one or more AC transmission system parameters to enhance controllability and increase power transfer capability. In general, FACTs controllers can be classified as follows Series Controllers Shunt Controllers Combined series and shunt Controllers Combined shunt and series Controllers Based on the power electronic devices used in the controller, the FACTS controllers can be classified as: (A) Variable impedance type FACTS Controller (B) Voltage Source Converter (VSC) based FACTS Controller The variable impedance type controllers include: (i) Shunt connected- Static Var Compensator (SVC) (ii) Series Connected-Thyristors Controlled Series Capacitor or Compensator (TCSC) (iii) Combined shunt and series connected Thyristors Controlled Phase Shifting Transformer (TCPST) of Static PST The VSC based FACTS controllers are: (i) Static synchronous Compensator (STATCOM) (shunt connected) (ii) Static Synchronous Series Compensator (SSSC) (series connected) (iii) Interline Power Flow Controller (IPFC) (combined series-series) (iv) Unified Power Flow Controller (UPFC) (combined shunt-series) The VSC based FACTS controllers have several advantages over the variable impedance type. VSC based STATCOM response is much faster than a variable impedance type SVC. STATCOM requires less space than SVC for same rating. It can supply required reactive power even at low values of the bus voltage. In addition, a STATCOM can supply active power if it has an energy source or large energy storage at its DC terminals. It can also be designed to have in built, short-term overload capability. The only drawback with VSC based controllers is that it requires use of self-commutating power semiconductor switches such as Gate Turn-off (GTO) thyristors, Insulated Gate Bipolar Transistors (IGBT), Integrated Gate Commutated Thyristors (IGCT). However, the VSC based controllers build with emerging power semiconductor devices using silicon carbide technology will lead to the wide spread use of VSC based controllers in future. Among FACTs controllers, the shunt controllers have shown feasibility in terms of cost effectiveness in a wide range of problem solving from transmission to distribution levels. For more than a decade, it has been recognized that the transmittable power through transmission lines could be increased and the voltage profile along the transmission line could be controlled by an appropriate amount of compensated reactive power. Moreover, the shunt controller can improve transient stability and can damp power oscillation during a post-fault event. Using a high speed power converter, the shunt controller can further alleviate the flicker problem caused by electrical arc furnaces. .1 SERIES CONTROLLERS Static synchronous series compensator (SSSC) is series reactive power compensation devices used in transmission level. The series compensation is obtained by controlling the equivalent impedance of a transmission line, to regulate the power flow through the line. The SSSC can be considered as a static synchronous generator that acts as a series compensator whose output voltage is fully controllable, independent of line current and kept in quadrature with it, with the aim of increasing or decreasing the voltage drop across the line, thus controlling the power flow. The basic structure of a SSSC connected with the network is shown in Figure 1.1. Line C VSC TF Figure.1.1 Series Connected SSSC The SSSC injects a voltage Vq in quadrature with line current. It can provide either capacitive compensation if Vq leads the line current by à Ã¢â€š ¬/2 rad or inductive compensation if Vq lags line current by à Ã¢â€š ¬/2 rad. A relatively small active power exchange is required to compensate for coupling transformer and switching losses, and maintain the required DC voltage. 1.2.2 SHUNT CONTROLLERS STATCOM The schematic diagram of a STATCOM is shown in Figure.1.2. In principle, all shunt type controllers inject additional current into the system at the point of common coupling (PCC). VSC that uses charged capacitors as the input dc source and produces a 3à Ã¢â‚¬ ¢ ac voltage output in synchronism and in phase with the ac systems. The converter is connected in shunt to a bus by means of the impedance of a coupling transformer. A control on the output voltage of this converter is either lower or higher than the connecting bus voltage, controls the reactive power drawn from or supplied to the connected bus. The impedance of the shunt controller, which is connected to the line causes a variable current to flow and hence represents an injection of current into the line. As long as the injected current is in phase quadrature with the line voltage, the shunt controller can either supply or consume variable reactive power. Line C VSC TF Figure.1.2 Shunt Connected STATCOM A six pulse Voltage Source Converter (VSC) with suitable controller, the phase angle and the magnitude of the AC voltage injected by the VSC can be controlled. The Phase Lock Loop (PLL) ensures that the sinusoidal component of the injected voltage is synchronized (matching in frequency and required phase angle) with the AC bus voltage to which VSC is connected through a coupling inductor. Often, the leakage impedance of the interconnecting transformer serves as the coupling inductor. It also serves as harmonic filter for the voltage injected by the VSC. The injection of harmonic voltages can also be minimized by multi-pulse (12, 24 or 48), and/or multilevel convertors. At low power levels, the pulse width modulation (PWM) technique is sufficient to control the magnitude of the fundamental component of the injected voltage. The high voltage IGBT devices can be switched at high frequency (2 kHz and above) of sinusoidal modulation enables the use of simple LC-low pass filters to reduce harmonic components. 1.2.3 COMBINED SHUNT AND SERIES CONTROLLERS (a). Unified Power Flow Controller (UPFC): The Unified Power Flow Controller (UPFC) is the most versatile FACTS controller for the regulation of voltage and power flow in a transmission line. It consists of two-voltage source converters (VSC) in which one connected in shunt and the other one connected in series. The DC capacitors of the two converters are connected as shown in Figure.1.3. the shunt connected converters work as STATCOM and controls the reactive current injected in to the line. Series connected converter work as SSSC and control reactive voltage injected series with the line. The combination of these two converters enables to exchange active power flow between the two converters. The series connected converter can supply or absorb the active power. VSC Line VSC C STATCOM SSSC Figure 1.3 Schematic of UPFC The controllable power source on the DC side of the series connected converter, results in the control of both real and reactive power flow in the line at the receiving end of the line. The shunt-connected converter provides the required reactive power and injects the reactive current at the converter bus. Thus, a UPFC has 3 degrees of freedom whereas other FACTS controllers have only one degree of freedom or control variable. The concept of combining two or more converters can be extended to provide flexibility and additional degrees of freedom. A Generalized UPFC refers to the use of three or more converters out of which one shunt connected while the remaining converters are series connected (b). Interline Power Flow Controller (IPFC): An Interline Power Flow Controller (IPFC) refers to the configuration of two or more series connected voltage source converters sharing a common DC bus as shown in Figure 1.4. The Interline Power Flow Controller (IPFC) is used reactive (series) compensation of each individual line. In addition to this, the IPFC is capable of exchanging real power between the two or more compensated lines. To achieve this AC side of the series connected VSCs are connected in different lines and on the DC side, all the DC capacitors of individual converters are connected in parallel. This is possible because all the series converters are located inside the substation in close proximity. VSC1 Line-1 VSC2 C SSSC1 SSSC-2 Line-2 Figure 1.4 Schematic of IPFC for two transmission line using two VSC An IPFC is similar to a UPFC in that the magnitude and phase angle of the injected voltage in the line (main system) can be controlled by exchanging real power with the second line (support system) in which a series converter is connected. The basic difference with a UPFC is that the support system in the UPFC is the shunt converter instead of a series converter. The series converter associated with the main system of one IPFC is termed as the master converter while the series converter associated with the support system is termed as the slave converter. The master converter controls both active and reactive voltage within limits while the slave converter controls the DC voltage across the capacitor and the reactive voltage magnitude. 1.3 APPLICATION FACTS CONTROLLERS IN DISTRIBUTION SYSTEMS Although the concept of FACTS was developed originally for transmission network, later on this has been extended since last decade for improvement of Power Quality (PQ) in distribution systems operating at low or medium voltages. In the early days, the power quality referred primarily to the uninterrupted power supply at acceptable voltage and frequency. In the modern context, power quality problem is defined as any problem manifested in voltage, current or frequency deviations that result in failure or malfunctioning of customer equipment. However, the increase in the use of computers, microprocessors and power electronic systems has resulted in power quality issues involving transient disturbances in voltage magnitude, waveform and frequency. The nonlinear loads not only cause power quality (PQ) problems but also very sensitive to the voltage deviations. The unbalanced load in the distribution system like single-phase railway loading creates power quality problem at the distributio n level. The highly inductive load like arc furnace is a major source of creating power quality problems in distribution network. Hingorani et al (1999), was the first to propose FACTS controllers for improving power quality in distribution systems. They have called it as Custom Power Devices. These are based on VSC with appropriate controller. Based on the types of connection with the distribution network the custom power devices classifications are given below; 1. Series connected Dynamic Voltage Restorer (DVR) 2. Shunt connected Distribution STATCOM (DSTATCOM) 3. Combined shunt and series connected Unified Power Quality Conditioner (UPQC). The Dynamic Voltage Restorer (DVR) is a series connected custom power device in the distribution systems. The DVR is analogous to a SSSC in the transmission system. The main function of a DVR is to reduce voltage sags seen by sensitive loads such as semiconductor manufacturing plant or a paper mill. They have been designed to compensate three phase voltage sags up to 35% for duration of time less than half a second (depending on the requirement). If the voltage sag occurs only in one phase as in the case of Single Line to Ground (SLG) faults then the DVR may be designed to provide compensation for sags exceeding 50%. The capacitor is designed to store energy in the range of 0.2 to 0.4 MJ per MW of load served. A DVR is connected in series with the distribution feeder through a transformer. The low voltage winding of the transformer is connected to the converter. If a DVR is used mainly to regulate the voltage at the load bus, it injects a series voltage of the required magnitude if i t detects a voltage sag else remains in stand-by mode during which the converter is bypassed or it is not injecting voltage. It is necessary to protect the DVR against the fault currents as in the case of a SSSC. A DVR with IGBT/IGCT devices can be controlled to act as a series active filter to reduce the voltage harmonics on the source side. It is also possible to balance the voltage on the load side by injecting negative and/or zero sequence voltages in addition to harmonic voltages. The distribution STATCOM (DSTATCOM) is similar to a STATCOM in transmission system that it uses a VSC of the required rating. However, the VSC used in a DSTATCOM is a 6-pulse converter with SPWM or Space Vector Modulated PWM (SVPWM) control over the magnitude of the injected AC voltage while maintaining a constant DC voltage across the capacitor. In DSTATCOM, faster power semiconductor devices such as IGBT or IGCT are used instead of GTO as in STATCOM. The rapid switching capability provided by IGBT (or IGCT) switches enables the use of DSTATCOM for balancing, active filtering and flicker mitigation. The unbalanced system is balanced by injecting negative sequence current to the system. The active filtering is done by injecting harmonic currents in the system. A DSTATCOM can be viewed as a controlled variable current source. If more power that is reactive is required for compensation in distribution system, dynamic capacitor rating is increased. To increase the dynamic rating in the capacitive range, a fixed capacitor can be connected in parallel with DSTATCOM. By connecting energy storage device such as a Superconducting Magnetic Energy Storage (SMES) or a battery charged by a separate charging system on the DC side, it is possible to exchange real power with the network for momentary interruptions or large voltage sags for a limited time. The combination of shunt and series active filters which are connected on the common DC side as shown in Figure.1.5 used as Unified Power Quality Conditioner. This configuration is inspired by the UPFC in the transmission system. Akagi.H (1996), suggest the possibility of a centralized UPQC at the distribution substation that will provide harmonic isolation between the sub-transmission system and distribution system. The series branch of UPQC provides this harmonic isolation in addition to voltage regulation and imbalance compensation. The shunt branch provides for harmonic and negative sequence current compensation in addition to DC link voltage regulation. A UPQC can be considered as the combination of DSTATCOM and DVR. A DSTATCOM is utilized to eliminate the harmonics from the source currents and balance them in addition to providing reactive power compensation to improve power factor or regulate the load bus voltage (Padiyar.K.R. 2007). DVR DSTATCOM Load VSC1 Line VSC2 C Vs PCC I_AF VL +VAF Figure 1.5 Schematic of a Unified Power Quality Controller (UPQC) The terminology is yet to be standardized. The term `active filters or `power conditioners is also employed to describe the custom power devices. Irrespective of the name, the trend is to increasingly apply VSC based compensators for power quality improvement. LITERATURE REVIEW Development of gate turn off capability of semiconductor switches opened a way to second-generation FACTs controller using voltage source converter (VSC). This VSC can be operated at high switching frequency to provide a faster response. The STATCOM is a shunt connected power converter based compensating device. Van Zyl. A, et.al proposed an idea for Converter based solution to power quality problems on radial distribution lines (1996). This is a first power converter based shunt compensator. The concept of STATCOM was disclosed by Gyuayi,.L (1988). The concept gives the characteristics of VSC that are suitable for grid connected FACTS controller application. In the older version of reactive power compensation device, the reactive power is drawn from energy storage devices such as capacitor in the case of Static Var Compensator (SVC), but in STATCOM power is circulated within the connected network. The energy storage components used in the STATCOM is much smaller in capacity than tho se used in the SVC. In 1995, the first +100MVA STATCOM was installed at the Sullivan substation of Tennessee Valley Authority (TVA) in northeastern Tennessee. This device is mainly used to regulate 161kV bus during the daily load variation to reduce the operation of the tap changer of a 1.2GVA 161kV/500kV transformer. The VSC used in this STATCOM is made up of eight two level VSC resulting a 48 pulse VSC. The output of each VSC is integrated by a complex interface zigzag connected interfacing transformers, because this is a two-level VSC, a series connection of five of gate-turn-off (GTO) thyristor is used as a main switch. The staircase type switching scheme at fundamental frequency (60Hz) was used as a control scheme for this STATCOM. Due to slow switching speed of the GTOs; the firing angles of the output wave form are fixed. Therefore, the amplitude of each output waveform is controlled by exchanging real power of the DC-link capacitor with the power grid. The power quality problem at distribution level like voltage regulation, harmonics reduction, power factor correction, reactive power compensation and unbalance compensations need to be carried out at distribution level. The DSTATCOM, connected to the grid through the coupling inductor at the point of common coupling (PCC) is controlled in such a way that it exchanges only reactive power with the grid. This is achieved by injecting current in quadrature with the grid voltage. The DSTATCOM is developed from the STATCOM used in transmission system for voltage regulation. Hingorani, N.G,. et al (1999) explored the concept and technology of Flexible AC Transmission Systems. The detailed modeling and average modeling of DSTATCOM and its performance for voltage regulation application is studied by Pierre Giroux et al (2000). This gives the concept of PWM controlled DSTATCOM in dq coordinate system. Sen Sarma. P.S., et al (2001) Analyzed and evaluated the performance of a distribution STATCOM for compensating voltage Fluctuations. Sao, C.K et al (2002) proposed the application of DSTATCOM from voltage regulation to reactive power compensation, power factor correction, mitigation of voltage sag and swell in distribution system and created a benchmark system to test all these performance. This DSTATCOM is controlled by PI controller in dq coordinate using parks transformation matrix. This work reduced the computation time of the controller by avoiding Inverse Parks transformation. The application of DSTATCOM is extended to compensate the reactive power for isolated induction generator by Bhim Singh et al (2003). This gave the mathematical modeling of induction generator and DSTATCOM. As the DSTATCOM is suitable for distribution system and stand alone system researcher focused to increase the performance of the controller. The concept of using DSTATCOM as a shunt active filter to reduce the current harmonics in the industrial application and gradually extended to power systems application by Georges, S. et al (2006) and Kannan, H.Y. et al (2008). The concept of Generalized Instantaneous Reactive Power Theory for Three-phase Power Systems is exploited by Akagi, P., et al (1984) and Fang Z heng Peng et al (1996). The concept of instantaneous reactive and real power is brought by them in to the design of controller for closed loop operation of VSC. A Survey of Current Control Techniques for Three-Phase Voltage-Source PWM Converters is brought by Marian P., et al (1998). These current control techniques provided a path way for direct control of VSC output current. Design and Implementation of DSTATCOM for fast load compensation of unbalanced loads was implemented by Wei-Neng Chang et al (2009). The controller for unbalanced system was built by phase sequence method and pulses are generated by current regulated PWM method. The Space Vector Modulation (SVM) PWM technique was an emerging control technique used in Voltage Source Converter (VSC) for controlling its output voltage by Atif Iqbal et al (2010). A New Vector-Based Hysteresis Current Control Scheme for Three-Phase PWM Voltage-Source Inverters was developed by Mansour Mohseni et al (2010). This thesis tries to appl y Vector-Based Hysteresis Current Control Scheme for DSTATCOM for power factor improvement. This research is focusing to use the SVM based PWM technique for DSTATCOM operation in addition to PI controlled SPWM in dq coordinate systems. This also extends the application SVM based HCC from inverter to DSTATCOM. 1.5 PROBLEM STATEMENT The voltage at distribution systems need to be maintained at 1pu at all conditions. The reactive power control plays an important role in maintaining the bus voltage at 1pu in the distribution bus.Classical reactive power controllers like fixed capacitors, switched capacitors, TCR, SVC etc have slow response and bulky. A DSTATCOM, though a costlier device it has faster response. Hence it is preferred when faster correction of voltages is required. It is required to design specific controllers for voltage regulation, power factor correction and unbalanced system compensations. All the above problems can be solved by installing a DSTATCOM with proper controllers. 1.6 OBJECTIVES The main aim of this thesis is to design and implement the controller for DSTATCOM to improve the power quality namely voltage regulation, voltage sag or swell, reactive power compensation, power factor improvement and unbalance compensation. The controllers presented in this work will aid the design engineers to develop an integrated controller with multiple control objectives. The main objectives of this thesis include To study the concepts of DSTATCOM and bring out the design procedure of it. To understand the controller principle for various applications and explore it for novel controller design. To design the new control algorithm namely PI controlled Space Vector Pulse Width modulation method and Study the performance of DSTATCOM for this controller to improve the power quality issues such as voltage regulation, power factor improvement and reactive power compensation. To compare this SVPWM controller performance with the performance of existing Sine Pulse Width Modulation (SPWM) method. To modify the basic SVPWM method so as to extend its controller to directly control the flow of current of DSTATCOM. This method of controller is called SVPWM based Hysteris Current Controller (HCC) method. To suggest a new control techniques for unbalanced system compensations using sequence analyzing method and validate its performance for power quality improve improvement. To explore the design of DSTATCOM components. To identify the controller for compensating balanced and unbalanced systems. 1.7 THESIS ORGANISATION This thesis contains seven chapters summarized as follows: In Chapter 1 need for improving the quality of power is discussed the power quality issues and various Flexible AC Transmission System (FACTS) controllers available for the power quality improvements in the transmission systems and distribution systems. This chapter also includes the review of the literature, outlines the research objectives and the organization of the thesis. Chapter 2 describes the general method for designing a DSTATCOM for power quality improvement. The DSTATCOM consists of a DC capacitor, a VSC, a coupling inductor and the controller. This chapter gives a method of designing the coupling inductor, the DC capacitor and selecting the power electronic switches for the VSC. It also focuses on analyzing the controllers of DSTATCOM for power quality improvements. In Chapter 3, the mathematical modeling of a two-level VSC based DSTATCOM is described. This Chapter also presents the PI controlled Sine Pulse Width Modulation (SPWM) and Space Vector PWM (SVPWM) switching techniques for voltage regulation applications. The comparative performance of these switching techniques is carried out. The control logic is developed from the power invariant property of the Parks transformation of

Evidence-Based Practice on Wound Packing

Evidence-Based Practice on Wound Packing Evidence-Based Practice on Wound Packing Following Incision and Drainage Arlena Davis The first article was related to MD’s not using any packing when it comes to treating I D’s. Many times packing is used to debride the wound and keep fluids from pooling under the skin as well as keep area free of infection. In order to understand the outcome we need to fully understand what is involved.An abscess is a collection of pus, surrounded by inflamed tissue and usually localized (Pfenninger Fowler, 2010).The reason we need the packing is related to having an abscess and we need to keep the area clean. Leinwand 2013states packing is thought to aid hemostasis, and prevent reorganization of the abscess, we sought to determine whether packing could be omitted with equal efficacy. The second article I chose was Alimov, V., Lovecchio, F., Sinha, M., Foster, K. N., Drachman, D. (2013)to the use ofa silver-containing hydrofiber dressing for filling abscess cavity following incision and drainage in the emergency department. Is using packing always effective? Can we have equal efficacy when there is no packing used? These are questions that were sought after and answered in this particular article. At the end of the trial the patients reported faster heling and les pain as it relates to traditional packing. In the research that was conducted in the first article entitled  Use of Silver-containing hydro fiber dressing in filling the cavity related after incision and drainage at the emergency department: a randomized controlled trial. Advances in skin wound care, (Alimov, Lovecchio, Sinha, Foster, Drachman, 2013), clinical study design was used. This study design took the form of prospective randomized control trial. The sample size in this case was ninety-two patients (Alimov, Lovecchio, Sinha, Foster, Drachman, 2013). These patients were more than 18 years of age and were suffering from cutaneous abscess. The ninety-two study participants had been randomly assigned into two groups. These are the intervention group (Skillman, Aquacel, New Jersey, and Convatec) and the iodoform group (Alimov, Lovecchio, Sinha, Foster, Drachman, 2013). The iodoform group is the control group in this case. Of these two groups, it was noted that there were no differences in terms of demography as well as their clinical characteristics. The weaknesses that are evident in data collection are that the researchers should have randomly selected the patients in two equal groups that is 46 persons per each group. The follow-up period is also not consistent. Inconsistency comes in whereby the study claims that patients were followed up in a span of the first two weeks (Alimov, Lovecchio, Sinha, Foster, Drachman, 2013), though the follow-up was not continuous. However, the strength of this study is that it had both the intervention group and the control group. The intervention group comprised of four subgroups depending on the intended intervention. These four groups were based on interventions such as Convatec, New Jersey, Aquacel, and Skillman) (Alimov, Lovecchio, Sinha, Foster, Drachman, 2013).The other strength of the study is that it was able to provide a comparison on the level of pain between the patients initial visit and the first follow-up. In relation to the second article that dealt with the incision and the drainage of the subcutaneous abscess without packing, (Leinwand, Downing, Slater, Beck, Burton, Moyer, 2013) clinical study design was also used. In this regard, the clinical study took the form of retrogressive randomized control trial. The sample size in this study was a hundred patients, who were reported to be suffering from subcutaneous abscesses back in between May 2008 and December 2010. These 100 patients were assigned into two groups namely, the packing and the non-packing groups (Leinwand, Downing, Slater, Beck, Burton, Moyer, 2013). In this case, there were some exceptions in that some patients portraying some given conditions could not be considered. Such conditions include; patients who are immunosuppressed, or rather those suffering from diabetes. The other exception was in case the patient had a perineal or a pilonidal abscess. Last but not least, the other exception was on whether the abscess is secondary to the previous operation. These exceptions can be used as a basis for comparison among the sample, to the patients who will be seeking treatment. There are several weaknesses of the study in terms of data collection, with one of them being that it was not age specific. Apart from that, the other weakness is that; the patients were only clinically evaluated, in case there was suspicion of recurrence in the follow-up calls on the day seven and thirty (Leinwand, Downing, Slater, Beck, Burton, Moyer, 2013). These two days were referred to as postoperative. The other weakness is that, of the 100 patients, only 85 patients managed to complete the study. The study does not indicate the whereabouts of the 15 patients. On the other hand, the strength of this study is that it omitted other patients who had some other conditions that could interfere with the results. Such exceptional cases were the diabetic, immunosuppressed (Leinwand, Downing, Slater, Beck, Burton, Moyer, 2013), among others. Identification, critical appraisal, and synthesis of evidence from research articles is an essential skill in evidence-based practice (EBP) (Titler, 2008). This paper will critique two primary research articles related to the issue of wound packing following incision and drainage. The first article is authored by Leinwand et al. (2013) and is entitled â€Å"Incision and drainage of subcutaneous abscesses without the use of packing†. The second article is authored by Alimov et al. (2013) and is entitled â€Å"Use of a silver-containing hydrofiber dressing for filling abscess cavity following incision and drainage in the emergency department: A randomized controlled trial†. The study by Leinwand et al. (2013) sought to determine whether omission of the wound packing component in the management of subcutaneous abscess has similar efficacy to wound packing. The study employed a prospective randomized controlled trial design whereby 100 participants were randomized to either the wound packing group or to the non-packing group. The study enrolled pediatric participants aged less than 18 years with subcutaneous abscesses. The sample size for the study was small (100). Consequently, the study did not have significant statistical power as a sample size of 4000 was required to gain power of 80%. The researchers, however, accepted the small sample size as it was practical for the purposes of the study. The selected sample is appropriate to the population of interest because the participants were experiencing the phenomenon of interest that is abscesses requiring incision and drainage. Regarding data collection, similar pre-intervention data was collected on the operative day for all participants. These data included age, gender, and location and size of the abscess. Post-intervention data was collected through follow-up telephone calls by a pediatric surgery nurse specialist. These calls were made on the 7th and 30th post-operative days and included information on general wound appearance, adherence with warm soaks and antibiotic therapy, presence of fever, and timing of pack removal. The reliance on self-reported information may have introduced information bias due socially desirable responding and problems with recall (Fadnes, Taube, Tylleskar, 2008). Of the 100 participants who enrolled for the study, only 85 completed the study. The study found that the packing group and non-packing groups did not vary statistically with respect to abscess recurrence rates, initial parameters, and incidence of methicillin-resistant staphylococcus aureus (MRSA). Only two abscess recurrences were reported, one for each group. In their discussion, the authors contextualize these findings in light of pre-existing evidence. They note that the findings of their study are identical to those of similar previous studies on both adults and children. The authors also compare the strengths and weaknesses and merits and demerits of their study and intervention with those of previous studies. They also discuss the two cases of treatment failure. Lastly, they provide recommendations for future studies. On the incorporation of evidence into treatment protocols, integration of research findings into treatment protocols/procedures occurs through the process of evidence-based practice. Research articles relevant to a clinical issue of concern are identified, appraised critically, and their findings used to make specific recommendations for practice on incision and drainage (Dontje, 2007). The Purpose of the Alimov et al. (2013) study was to investigate whether packing of abscess cavity with a silver-containing hydrofiber dressing instead of the standard iodoform dressing leads to less pain and faster wound healing. The study employed a prospective randomized controlled trial design whereby participants were randomized to the silver-containing hydrofiber or standard care groups. The study population consisted of adults aged more than 18 years who visited the emergency department of a teaching hospital with cutaneous abscesses >2cm in diameter that required incision and drainage. The selected sample consisted of 92 patients. The sample for the study is appropriate to the selected topic as it focuses on the issue of incision and drainage protocols. Data for the study was collected and documented on a standard form except for pain. The data collected included pertinent demographic and clinical variables. Pain was assessed using a self-report scale, the Wong-Baker FACES Pain Rating Scale. The use of a self-report scale for pain may have introduced social desirability bias. The findings of the study may have also been contaminated by bias due to the manual measurement of the dimensions of the abscess cavities. The primary outcome measures for the study were the proportion of patients with a reduction of 30% or > in the surface area of the abscess at the first follow up visit (between 48 and 72 hours). The other main outcome variable was proportion of patients with 30% or > decrease in the surrounding cellulites at the first visit. The secondary outcome measure was the change in self-reported pain intensity at primary and consequent visits. The study found that 82.6% of the patients in the silver-containing hydrofiber group had a reduction of 30% or > in the surface area of the abscess compared to the 26.1% of the subjects in the iodoform group (p In this article, the number of participating pediatric patients who had subcutaneous abscesses was one hundred. Patients who successfully completed the study were only 85: 43 packing group and 42 non-packing group. There existed an arithmetic variance between the two groups that concerned the initial parameters, recurring abscesses, (single in every group), or incidence of MRSA (81.4 packing groups over 85.7 non-packing group). Subcutaneous abscesses incision, as well as drainage without the utilization of packing, is an effective as well as a safe technique. This article should present the data in a more transparent way. In this article, there was a prospective enrollment of 92 patients and these patients. There was also random assignment of these patients to the iodoform groups or Aquacel Ag. The SD was 12.0, and the average age was 38. The patients in iodoform group were 43 while those in Aquacel group were 49. There two groups lacked disparity in clinical and demographic characteristics. The domino effect of the deterioration study pointed out that the Aquacel Ag was autonomously associated with over 30% abscesses’ surface area reduction. This, however excluded first follow-up cellulitis. The pain intensity also decreased significantly as perceived by the Aquacel group patients. In cutaneous abscesses patients, there was faster wood healing as well as pain reduction while using antimicrobial-hydro fiber ribbon form of dressing than while using iodoform dressing. This article is important as it offers information on which choice is best while dressing. It is recommended thatmore research on this subject as this will provide more information on subcutaneous abscesses treatment. These articles will help me in my career as a nurse practitioner because of the versatility of the procedures and the information provided. In summary, this paper has critiqued two research articles related to the issue of wound packing following incision and drainage. The articles by Leinwand et al. (2013) and Alimov et al. (2013) have been critiqued in terms of their purpose, design, sample, data collection procedures, results, and discussion. References Alimov, V., Lovecchio, F., Sinha, M., Foster, K. N., Drachman, D. (2013). Use of a silver- containing hydrofiber dressing for filling abscess cavity following incision and drainage in the emergency department: A randomised controlled trial. Advances in Skin and Wound Care, 26, 20-25. Dontje, K. J. (2007). Evidence-based practice: Understanding the process. Topics in Advanced Practice Nursing, 7(4). Fadnes, L., Taube, A., Tylleskar, T. (2008). How to identify information bias due to self-reporting in epidemiological research. The Internet Journal of Epidemiology, 7(2). Leinwand, M., Downing, M., Slater, D., Beck, M., Burton, K., Moyer, D. (2013). Incision and drainage of subcutaneous abscesses without the use of packing. Journal of Pediatric Surgery, 48(9), 1962-1965. Titler, M. G. (2008). The evidence for evidence-based practice implementation. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK2659/

Warrior Marks :: essays research papers

Alice Walker, Warrior Marks: Female Genital Mutilation and the Sexual Blinding of Women. New York: Harcourt Brace, 1993, 373pp. Female genital mutilation, also known as female circumcision, is a practice that involves the removal of part or all of the female external genitalia. It occurs throughout the world, but most commonly in Africa where they say that it is a tradition and social custom to keep a young girl pure and a married woman faithful. But to some Westerners, the practice is viewed as being primitive and barbaric. We react with disgust and find it nearly incomprehensible that female genital mutilation can occur in the world today   Ã‚  Ã‚  Ã‚  Ã‚  In Warrior Marks, Alice Walker looks at the reality that millions of African, Asian and Indian women suffer from genital mutilation. The book begins with the re-telling of a story of how she lost one eye. This wound was inflicted on her when she was three years old and for years, she felt handicapped and isolated. Her brother, who caused this accident with a BBgun, is referred to as a â€Å"warrior† and the blinding of her eye is the warrior mark. Her visual mutilation is what helped her see the subject of genital mutilation. She sees it as a terrible form of patriarchal oppression, characterized by â€Å"the feeling of being overpowered and dominated by those you are bound to respect.† The book goes on and discusses the health risks that are involved in the practice. It talks about how the women who perform the surgery have a minimal knowledge of anatomy and hygiene, which results in infections of the genital and often results in the transmission of the HIV virus. Besides the initial pain of the operation, these girls also suffer long-term physiological, sexual and psychological effects. A mother reveals that she would stop the pain and betrayal if she could but because of tradition, she and others would risk banishment, torture and abuse.   Ã‚  Ã‚  Ã‚  Ã‚  In the end, Walker emphasizes that these African women are not victims, but survivors. In the book, the women grow gardens on dry land and trade food, clothing and crafts in the marketplace. Whether a battered wife, a rape survivor or genitally mutilated woman, Walker concludes that a woman warrior learns that if she is injured, she can fight back. She closes by saying, â€Å"Your wound could be your guide.†   Ã‚  Ã‚  Ã‚  Ã‚  Female circumcision is based on gender oppression and degradation of women.

Another Heart of Darkness Essay -- essays research papers

Ignorance and Racism Joseph Conrad develops themes of personal power, individual responsibility, and social justice in his book Heart of Darkness. His book has all the trappings of the conventional adventure tale - mystery, exotic setting, escape, suspense, unexpected attack. Chinua Achebe concluded, "Conrad, on the other hand, is undoubtedly one of the great stylists of modern fiction and a good story-teller into the bargain" (Achebe 252). Yet, despite Conrad's great story telling, he has also been viewed as a racist by some of his critics. Achebe, Singh, and Sarvan, although their criticisim differ, are a few to name. Normal readers usually are good at detecting racism in a book. Achebe acknowledges Conrad camouflaged racism remarks, saying, "But Conrad chose his subject well - one which was guaranteed not to put him in conflict with psychological pre- disposition..." (Achebe, 253). Having gone back and rereading Heart of Darkness, but this time reading between the lines, I have discovered some racism Conrad felt toward the natives that I had not discovered the first time I read the book. Racism is portrayed in Conrad's book, but one must acknowledge that back in the eighteen hundreds society conformed to it. Conrad probably would have been criticized as being soft hearted rather than a racist back in his time. Conrad constantly referred to the natives, in his book, as black savages, niggers, brutes, and "them", displaying ignorance toward the African history and racism towards the African people. Conrad wrote, "Black figures strolled out listlessly... the beaten nigger groaned somewhere" (Conrad 28). "They passed me with six inches, without a glance, with the complete, deathlike indifference of unhappy savages" (Conrad 19). Achebe, also, detected Conrad's frequent use of unorthodox name calling, "Certainly Conrad had a problem with niggers. His in ordinate love of that word itself should be of interest to psychoanalysts" (Achebe 258). Conrad uses Marlow, the main character in the book, as a narrator so he himself can enter the story and tell it through his own philosophical mind. Conrad used "double speak" throughout his book. Upon arriving at the first station, Marlow commented what he observed. "They were dying slowly - it was very clear. They were not enemies, they were not cri... ... (Singh 278). Conrad didn't write his book to the extreme of racism. Overall, the natives appeared better humans than the Europeans in Heart of Darkness. Conrad's ignorance led to his conformity to racism. His ignorance of not completely "granting the natives human status" leads him to social categorization. C. P. Sarvan wrote in his criticism, quoting Achebe, "Racism and the Heart of Darkness," "Conrad sets up Africa 'as a foil to Europe, a place of negations... in comparison with which Europe's own state of spiritual grace will be manifest.' Africa is 'the other world,'..." (281). Achebe, Chinua [An Image of Africa: Racism in Conrad's Heart of Darkness.] Heart of Darkness. By Joseph Conrad 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical 1988. Conrad, Joseph Heart of Darkness 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical, 1988. Sarvan, C. P. [Racism and the Heart of Darkness.] Heart of Darkness. By Joseph Conrad 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical 1988. Singh, Frances B. [The Colonialistic Bias of Heart of Darkness.] Heart of Darkness. By Joseph Conrad 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical 1988. Another Heart of Darkness Essay -- essays research papers Ignorance and Racism Joseph Conrad develops themes of personal power, individual responsibility, and social justice in his book Heart of Darkness. His book has all the trappings of the conventional adventure tale - mystery, exotic setting, escape, suspense, unexpected attack. Chinua Achebe concluded, "Conrad, on the other hand, is undoubtedly one of the great stylists of modern fiction and a good story-teller into the bargain" (Achebe 252). Yet, despite Conrad's great story telling, he has also been viewed as a racist by some of his critics. Achebe, Singh, and Sarvan, although their criticisim differ, are a few to name. Normal readers usually are good at detecting racism in a book. Achebe acknowledges Conrad camouflaged racism remarks, saying, "But Conrad chose his subject well - one which was guaranteed not to put him in conflict with psychological pre- disposition..." (Achebe, 253). Having gone back and rereading Heart of Darkness, but this time reading between the lines, I have discovered some racism Conrad felt toward the natives that I had not discovered the first time I read the book. Racism is portrayed in Conrad's book, but one must acknowledge that back in the eighteen hundreds society conformed to it. Conrad probably would have been criticized as being soft hearted rather than a racist back in his time. Conrad constantly referred to the natives, in his book, as black savages, niggers, brutes, and "them", displaying ignorance toward the African history and racism towards the African people. Conrad wrote, "Black figures strolled out listlessly... the beaten nigger groaned somewhere" (Conrad 28). "They passed me with six inches, without a glance, with the complete, deathlike indifference of unhappy savages" (Conrad 19). Achebe, also, detected Conrad's frequent use of unorthodox name calling, "Certainly Conrad had a problem with niggers. His in ordinate love of that word itself should be of interest to psychoanalysts" (Achebe 258). Conrad uses Marlow, the main character in the book, as a narrator so he himself can enter the story and tell it through his own philosophical mind. Conrad used "double speak" throughout his book. Upon arriving at the first station, Marlow commented what he observed. "They were dying slowly - it was very clear. They were not enemies, they were not cri... ... (Singh 278). Conrad didn't write his book to the extreme of racism. Overall, the natives appeared better humans than the Europeans in Heart of Darkness. Conrad's ignorance led to his conformity to racism. His ignorance of not completely "granting the natives human status" leads him to social categorization. C. P. Sarvan wrote in his criticism, quoting Achebe, "Racism and the Heart of Darkness," "Conrad sets up Africa 'as a foil to Europe, a place of negations... in comparison with which Europe's own state of spiritual grace will be manifest.' Africa is 'the other world,'..." (281). Achebe, Chinua [An Image of Africa: Racism in Conrad's Heart of Darkness.] Heart of Darkness. By Joseph Conrad 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical 1988. Conrad, Joseph Heart of Darkness 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical, 1988. Sarvan, C. P. [Racism and the Heart of Darkness.] Heart of Darkness. By Joseph Conrad 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical 1988. Singh, Frances B. [The Colonialistic Bias of Heart of Darkness.] Heart of Darkness. By Joseph Conrad 3rd ed. Ed. Robert Kimbrough. New York: Norton Critical 1988.

Salem Telephone Company – Essay

Salem Telephone Company 1. ) Variable and Fixed Costs The variable costs that Salem Data Services incurs with respect to revenue hours are power usage and hourly personnel wages. Power usage is a variable cost because the monthly power expense changes as a result of how much of the computer service is used. The hourly personnel wages are a variable cost as well because hourly workers are required to work when the computer service is operational. The revenue hours change each month and this causes the hourly workers salary to change too.The fixed costs, with respect to revenue hours, are rent and custodial services for the space that is leased by Salem Data Services as well as the computer leases, maintenance, depreciation of the computer equipment and the depreciation of the office equipment and fixtures. Other fixed costs include the salaried staff in charge of operations, the salaried staff that are in charge of the systems development and maintenance, the administration staff and the sales staff, which are also salaried. These are all fixed costs because they stay the same each month and are not affected by the change in revenue hours each month.The last two fixed costs are sales promotion and corporate services. Sales promotion is considered a fixed cost because the expense is not related to the current level of work. This cost was determined by the managers’ estimation of how much they needed to spend in order to acquire new clients. Corporate services are also considered a fixed cost because they not related to the level of work or monthly revenue hours that are generated. Exhibit 1A on the attached worksheet shows the variable and fixed cost breakdown for each month. 2. ) Cost Per Revenue HourFor the power variable cost, the cost per revenue hour is found by taking the power expense for each month and dividing it by the total revenue hours for each month. For January, the power expense is $1,546 and the total revenue hours are 329. The cost per re venue hour is $4. 70 ($1,546/329). For February, the power expense is $1,485 and the total revenue hours are 316. The cost per revenue is $4. 70 as well ($1,485/316). For March, the power expense is $1,697 and the total revenue hours are 361. Cost per revenue is again $4. 70 ($1,697/361).For the hourly personnel, the steps taken above are used to compute the cost per revenue. For January, the hourly personnel wages are $7,896 and the total revenue hours are 329. The cost per revenue hour is $24 ($7,896/329). In February, the hourly personnel wages are $7,584 and total revenue hours are 316. The cost per revenue hour is again $24 ($7,584/316). Finally in March, the hourly personnel wages are $8,664 and the total revenue hours are 361. The cost per revenue hour comes out to be $24 ($8,664/361). The total cost per revenue hour for each is $28. 0 and this is computed by adding the cost per revenue hour for the power expense and the hourly personnel together. These calculations can be fo und in Exhibit 2A on the attached worksheet. 3. ) Contribution Margin Income Statement Exhibit 3A on the attached worksheet shows the contribution margin income statement for Salem Data Services when Salem Telephone usage is 205 hours and the commercial usage is at the March level of 138 hours. The total sales are $192,400 of which $82,000 belongs to sales made from Salem Telephone at a $400 sales price and $110,400 of this belongs to commercial usage at a sales price of $800.The total variable costs are $9,844. 10. This was found by taking the total cost per revenue hour of $28. 70 and multiplying it by the total revenue hours, which were 343 (205+138). The contribution margin is $182,555. 90. This was determined by taking the total sales of $192,400 and subtracting out the variable costs of $9,844. 10. To get the net income, the total fixed costs of $212,939 are subtracted from the contribution margin, which produces a loss of ($30,383. 10). 4. ) Breakeven Point In order for Salem Data Services to breakeven each month, they will need to produce roughly 178 hours.Exhibit 4A on the attached worksheet shows the equation and calculation for the breakeven point. The equation for breakeven point is total sales equals total cost (variable and fixed). The total sales for Salem Data Services was the intracompany sales of $82,000 (205 hours X $800) plus the commercial sales of $800(X). The (X) represents the amount of unknown commercial hours that we are trying to find. The total costs are the cost per revenue hour of $28. 70 multiplied by both the 205 intracompany hours and the unknown commercial hours (X) plus the fixed costs of $212,939.The breakeven point is 40 more hours than Salem Data Services sold in March. Overall, from January to March, the amount of commercial hours sold has increased, but in small increments. Salem Data could reach this breakeven point in a future month if their hours continue to increase, but they will be susceptible to an increase in the ir variable costs and an increase in a couple of their fixed costs, such as sales promotion and corporate services. 5. ) Income Effect Estimation In option 1, Flores has suggested that Wu increase the price to commercial customers from $800 to $1,000.He projects that this will decrease demand by 30%. If this were to occur, the net income would be a loss of ($42,995). Exhibit 5A on the attached worksheet illustrates how this number was determined. Total sales were $178,600, variable costs were $8,656, and fixed costs were $212,939. When the variable fixed costs were subtracted from the total sales, this produced the loss mentioned above. Option 1 would not be a viable option for Salem Data Services because it still produces a negative net income.In option 2, Flores suggested that Wu decrease the price to $600 for commercial customers. Making this change is projected to increase demand by 30%. In this projection, net income will still be a loss of ($34,331). Exhibit 5B illustrates how this number was determined. Total Sales were $189,640, variable costs were $11,032, and fixed costs were $212,939. After the variable and fixed costs were subtracted from the total sales, the effect was a loss. Option 2 would also not be a viable option for Salem Data Services because again it still produces a negative net income.In option 3, Flores has suggested to Wu that increased promotion would increase revenue by 30%, but Wu is not sure how much promotion would be needed. To find how much promotion would be needed, we calculated the effect of the 30% increase. The price in this option remained at $800 for commercial customers. Exhibit 5C illustrates this. The total sales were $225,520, variable costs remained the same as in option 2 of $11,032, and fixed costs were still $212,939. When the variable and fixed costs were subtracted from the total sales, this produced a positive net income of $1,549.Wu should increase the sales promotion expense by this amount to generate positi ve income. This, however, is contingent upon the demand increasing by 30%. 6. ) Based on my analysis, Salem Data Services is a problem to Salem Telephone Company right now because even with a price increase or a demand increase, the company will still produce a loss. If Flores were to close down Salem Data Services, he would save Salem Telephone Company the following costs: Rent| $8,000| Maintenance| $5,400| Power| $1,697| Operations: Salaried Staff| $21,600| Operations: Hourly Personnel| $8,664|Systems Development and Maintenance| $12,000| Administration| $9,000| Sales| $11,200| Sales Promotion| $8,083| Total| $85,644| The custodial services and the expenses for the equipment and depreciation are not included in this list because the custodial services were based on an estimated annual cost per square foot and will still have to be paid for the remaining months of the year. The leases for are noncancelable and will still have to be paid until the lease period is up. The depreciatio n will also still occur while Salem Telephone has the equipment in their possession.Moreover, I did not include the corporate services in this list because I assume that Salem Telephone will still have to collect some accounts receivable and will still try to collect on past-due accounts, even after Salem Data Services is closed. Furthermore, if Flores decides to shut down Salem Data Services, he will have to outsource his computer services to another company and pay the market price of $800 instead of $400, which is currently being paid to Salem Data Services. If Salem Telephone were to use the 205 hours as estimated previously, then the company would have to pay $164,000 (205 hours X $800) monthly to another ompany. This means that Salem Telephone would end up paying $78,356 ($164,000-$85,644) more to another company rather than keeping Salem Data Services in business. My recommendation to Flores would be to keep Salem Data Services open. I believe as Wu does that given time, the company will start to generate a profit. In the meantime, Flores should have Wu keep the price of commercial usage at $800, but try to increase demand by 30% to at least breakeven each month. Once this occurs, then Wu should increase sales promotion to try to obtain more customers and increase commercial usage.