Free Essays on Livvie

â€Å"Livvie†, A Celebration of life Eudora Welty’s â€Å"Livvie†, is a great story on how life should be celebrated. The story is about a young woman , who marries and old man, that in a since imprisons her. The young girl gets a second chance at life when a younger man (someone her own age) enters her life and the older man is about to die. The theme Welty is trying to get across is live life to the fullest. Welty shows the theme through the character, setting, and symbols. Characters played a big role in the story. First, Solomon who is the husband of young woman. His name kind of explains what type of man he is going to be in the story. Solomon was the king of Israel and in the story Welty provides information that Solomon is playing a king type role. Welty says Solomon had a bed â€Å"like a throne† (511). â€Å"Solomon had never let Livvie go any farther than the chicken house and the well. (515). Welty shows the control Solomon has over Livvie (the young girl). Another sign of control that Welty shows in the story is, â€Å"Solomon would not have let Livvie look at them, just as he would not let her look at a field hand or a field hand look at her† (512 about cosmetics, Livvie gets so excited about the color of the lipstick. It must remind her of something in life. Cash’s youth attracts Livvie. The setting also plays a signi... Free Essays on Livvie Free Essays on Livvie â€Å"Livvie†, A Celebration of life Eudora Welty’s â€Å"Livvie†, is a great story on how life should be celebrated. The story is about a young woman , who marries and old man, that in a since imprisons her. The young girl gets a second chance at life when a younger man (someone her own age) enters her life and the older man is about to die. The theme Welty is trying to get across is live life to the fullest. Welty shows the theme through the character, setting, and symbols. Characters played a big role in the story. First, Solomon who is the husband of young woman. His name kind of explains what type of man he is going to be in the story. Solomon was the king of Israel and in the story Welty provides information that Solomon is playing a king type role. Welty says Solomon had a bed â€Å"like a throne† (511). â€Å"Solomon had never let Livvie go any farther than the chicken house and the well. (515). Welty shows the control Solomon has over Livvie (the young girl). Another sign of control that Welty shows in the story is, â€Å"Solomon would not have let Livvie look at them, just as he would not let her look at a field hand or a field hand look at her† (512 about cosmetics, Livvie gets so excited about the color of the lipstick. It must remind her of something in life. Cash’s youth attracts Livvie. The setting also plays a signi...

Cohabitation Essay Example | Topics and Well Written Essays - 2500 words

Cohabitation - Essay Example The leveling of the divorce rate is covering up the instability in the rising rates of cohabitation that is being passed from generation to generation. Cohabitation outside marriage sociologically changes the formation of the family unit. In a cohabitation arrangement, there is no legal commitment on the part of the spouses in regards to property and long-term child care arrangements. Because it leaves the children at risk, and due to religious and moral values, the act of cohabitation often carries a certain amount of social stigma with it. Yet, research has also shown that couples who cohabitate are significantly more likely to get divorced if the cohabitation progresses into marriage. A study by DeMaris and Rao (1992) concluded that "cohabitors have a higher hazard of dissolution at any given time since marriage. [and] cohabitors are estimated to have a hazard of dissolution that is about 46% higher than for noncohabitors" (p.183). The increased rate of divorce among previously cohabitating couples may be a product of an instability in the relationship from the beginning. According to Bumpass, Sweet, and Cherlin (1991), "About 4 0% of cohabiting unions in the United States break up without the couple getting married, and this tends to occur rather quickly. By about one and one-half years, half of cohabiting couples have either married or broken up" (p.917). Whether the cohabitation arrangement dissolves quickly, or ends in divorce after a later marriage, the prospects for a cohabitating couple are significantly worse than for a couple that marries without ever cohabitating. The rates of divorce and cohabitation have been historically measured by the Census Bureau. According to Fitch, Goeken, and Ruggles (2005), "The acronym POSSLQ-"Persons (or Partners) of Opposite Sex Sharing Living Quarters"-was coined by Census Bureau staff in the late 1970s. POSSLQ households-termed "Unmarried Couple Households" by the Census Bureau-are composed of two unrelated adults of the opposite sex (one of whom is the householder) who share a housing unit with or without the presence of children under 15 years old" (p.2). Divorce rates in theUnited States rose sharply in the period of 1960-1980 followed Chart 1: Source (Schoen & Canudus-Romo) by a leveling off period through the year 2000 (See Chart 1). During this same period, the Percentage of Opposite Sex Sharing Living Quarters rates have continued to rise sharply (See Chart 2). Chart 2: Source (Fitch, Goeken, & Ruggles) An interesting aspect of the divorce and cohabitation rates is that as the cohabitation rate was low and remained steady from 1960-1970, the divorce rate rose sharply. However, during the period of 1975-2005, cohabitation rates have risen dramatically, while the divorce rate has remained steady. From a psychological standpoint, it would seem that a relationship that has transgressed from a cohabitation arrangement to a marriage would have a better chance of success. The partners would be familiar with each other's living habits and the commitment to marriage would be based on a well informed couple. As would be expected, cohabitation has a higher dissolution rate than marriage, but this also extends to the couples who have married and now experience a higher divorce rate. Several studies have confirmed that couples who have

Athletes drug use Essay Example | Topics and Well Written Essays - 1000 words

Athletes drug use - Essay Example Covered in the subsequent paragraphs are types of drugs abused by athletes, reasons as to why they abuse drugs, associated effects, policies and punishments and finally, possible solutions to the problem. The sole aim of one taking part in a sporting completion, just like is the case with any other kind of completion is to emerge victorious. However, sometimes the prediction of the outcome may leave the competitor feel like he/she has already lost to his/her opponents even before the real competition. This is the main drive behind use of drugs by some athletes, just to ensure that they emerge winners and land their hands on the gold medal for their country while at the same time ensuring personal accomplishment satisfaction. . The former refers to the kinds of drugs which are usually taken with the aim of one getting the ability to perform better especially in athletics. With respect to Examples of PEDs include stimulants, human growth hormone (HGH), anabolic steroids, erythropoietin and diuretics (Audran et al, 1999). The second type of drugs (recreational drugs) comprise of those drugs, usually narcotic which are taken for the purpose of helping an individual alter his/her mood. In other words, these are drugs which are taken non-medically for the purpose of enjoyment and not because one is sick. Examples of drugs other this category include psychedelic mushrooms, cannabis, barbiturates, opium, amphetamines and heroin. An athlete will feel satisfied if at the completion of the game it turns out that he/she emerged the winner. However, as it is obvious, one cannot be said to have won the race if he/she has not yet taken part in a given completion. It is both the victorious feeling associated with winning and the intense feeling of competition that leaves some athletes with no option but to abuse some certain drugs. When an athlete wins a race, he/she is sure of taking home (to his/her home country) a medal, getting a good

Global Retail and the Transfer of Management Knowledge Case Study

Global Retail and the Transfer of Management Knowledge - Case Study Example There was much friction to be overcome if convenience stores were to be successful in Japan. This was mainly because of the overwhelming presence of small shops in the area. A lot of laws and regulations were put into place to try to protect these small shop owners, such as laws restricting large retailers-such as department stores-from certain activities (Bernstein, 2008). The company was brought to Japan mainly because of Toshifumi Suzuki. The company which he represented, Ito-Yokado, did not support the idea of bringing the convenience store to Japan as a franchise. However, Suzuki did support the idea and claimed that not only could profits be generated by convenience stores, but that the concept could also result in lessened friction between stores of different sizes. The number of small stores in the country was seen to Suzuki as an opportunity rather than a challenge. His idea was to build a franchise system of convenience stores and, in exchange for a cut of their profits, offer them managerial expertise and other guidance. He obtained knowledge from Southland with regards to how to operate a franchising system. Eventually, Suzuki was able to convince Masatoshi Ito to at least look into the idea (Bernstein, 2008). There were quite a few right moves by the company that led to it being such a large success in Japan. The company sent its amateurs for training in the United States. They knew to avoid price competition with supermarkets. They utilized Southland's accounting system. The setup of the store itself was perceived to the Japanese as being foreign, which had an appeal of its own. Ito-Yokado had such a great market power that Seven-Eleven Japan was able to leverage it to acquire wholesalers. The company positioned its stores in urban areas to attract individuals who only wanted a few items and were in a hurry. They carried a broad array of items for sale (Bernstein, 2008). When the model was re-exported to the United States, the Japanese had learned what mistakes to avoid by observing Southland's slow demise. They used some of the techniques that they utilized in their own country in order to make the convenience store change successful in the United States. One of the biggest keys to doing this was through adapting the latest in information technology. Since that concept had been so successful in Japan, the Japanese figured it could only do the same for the United States. In conclusion, this was a relatively unforeseen event-at least of its scope-in Japanese history. Japanese companies in the retailing industries were not seen worldwide as being efficient. Their distribution systems were archaic at best, and large retail giants such as Wal-Mart were few and far between. Using the skills they learned from Southland and their own parent company, Seven-Eleven Japan was very successful (Bernstein, 2008). Why did 7-Eleven thrive while Southland declined and eventually went bankrupt' Why, more in general, are there so many successful global retailers of non-US origin' 7-Eleven thrived not only because of the reasons discussed above, but also because of several other key factors. These include its franchise system and market dominance strategy, the rationalization

Chili’s Bar Essay Example for Free

Chili’s Bar Essay In the decision making process, it helps to look at all the information. This SWOT is comparing Chili’s restaurant to two of its competitors, Ruby Tuesday’s and Applebee’s. Company History Chili’s restaurants are part of the company, Brinker International Corporation. Chili’s Bar Grill is a casual dining restaurant that was founded in 1975 and has expanded to include 1,200 restaurants located domestically and internationally. There menu consists of fresh and healthy American dishes and limited amount of southwestern style Mexican dishes. In the last 30 years, Chili’s has created an identifiable, recognizable brand name, just think of the commercials. Chili’s Strengths Chili’s is the one of the largest full service restaurant chains with over 1,200 stores, second only to Applebee’s which has about 1,900 stores. Their competitor Ruby Tuesday has less than 900 stores with many of those franchises. Chili’s is part of Brinker Intl. , which is world’s second largest casual dining restaurant operator, the first being Darden restaurants. This allows them to offer affordable prices, because they can negotiate product rates for all of their stores, unlike a smaller company. They have also expanded their company to include Chili’s Too, Small Town Chili’s, and offer catering services. They update their menu one to two times a year, unlike Ruby Tuesday’s which updates their menu every three to four months. Chili’s has a popular menu that keeps people coming back, so they tweak it a bit to keep up with trends, but keep their core items. At this time they serve the same menu in every store, which allows for consistency throughout the company. They have a very broad market with a recognizable brand name and they focus on customer satisfaction. The restaurant business can be very competitive, but they have unusually high management retention and that may be in part to extremely competitive starting salaries and excellent benefit packages. Their competitor, Ruby Tuesday, has franchised many of its stores, creating varied salaries, salary caps, and benefits, when going from a franchise to a corporate store, which can make it difficult to retain managers. When Chili’s is looking for hourly employees, it offers several opportunities to them. They can apply and interview online, receive benefits and have the opportunity to grow with the company. Their hourly employee turnover rate is also lower than the industry average. Chili’s Weaknesses Even though the Chili’s brand is recognizable, it doesn’t appeal to the upper class. The casual dining concept, no matter how different, is still the same. They receive much of their food frozen, unlike Ruby Tuesday which receives all of their meat and produce fresh, making some items not the best of quality. During the busy times, servers are pressured to decrease their table turn time, the time from when a guest sits at the table until they leave and the table is ready for another guest, which can make it difficult to build a rapport with their guests, but at the same time they want their PPA (per person average) to be higher. Many of their restaurants are focused around the bar, which segregates some consumers that do not want to be in that environment. It also makes their seating area than some of their competitors. Chili’s Opportunities There are several things Chili’s can do to remain competitive in the casual dining industry. They can continue to expand internationally, beyond the 20 countries they are already in. Their competitors have yet to exceed that with Ruby Tuesday’s being in about twelve countries and Applebee’s is in almost twenty. They have a very well known brand which will allow them to continue expansion at a rapid rate with the backing of their parent company, Brinker Intl. They are launching a program to try international cuisines at some of their foreign locations. If consumers react positively this could be a great growth opportunity, if it is not taken to, it could be a threat to their international stores if they continue it. They can enlarge their restaurants or configure different models, based on the demographics of the area, to include more seating for guests and not just the bar area. They can continue to expand their brand recognition apparel and glassware. Chili’s Threats The largest threat to the Chili’s brand is the competition of casual dining restaurants, which are easy to duplicate. Applebee’s and Ruby Tuesday’s both had higher 1-year sales growths, with 10% and 17. %, respectively, compared to Chili’s at 6. 1%. Chili’s saturated some U. S. markets and has no where else to expand in those areas. They need to keep up with current trends and eating habits, because they change often, to stay current with the market. Summary Chili’s has managed to saturate the US and foreign markets better than its competitors. Their sales are higher and they retain their employees longer. They need to look at a few things like following eating trends and standing out from the competition a bit more, but they are a highly competitive company that keeps people coming back.

Aristotle’s Elements of Tragedy Essay -- Creek, Poetics, Tragedy

Aristotle is one of the most important western philosophers in history that has influenced our society in many aspects. Many of Aristotle’s teachings have affected our world for many years and still continue to have such a big impact. Some of the subjects Aristotle has influenced include: logic, physics, government and poetry. Aristotle’s study of poetry mainly focused on the elements to a good tragedy. Some of his elements have been used in Greek tragedies and modern movies. The Greek play, Medea, and the modern movie, No Country for Old Men, use elements from Aristotle philosophy, while using similar and different techniques but both achieving an effective tragedy. In Aristotle’s book, Poetics, he defines tragedy as, â€Å"an imitation of an action that is serious, complete, and possessing magnitude; in embellished language, each kind of which is used separately in the different parts; in the mode of action and not narrated; and effecting through pity and fear† (Aristotle 1149). Tragedy creates a cause and effect chain of actions that clearly gives the audience ideas of possible events. The six parts to Aristotle’s elements of tragedy are: Plot, character, language, thought, spectacle, and melody. According to Aristotle, the most important element is the plot. Aristotle writes in Poetics that, â€Å"It is not for the purpose of presenting their characters that the agents engage in action, but rather it is for the sake of their actions that they take on the characters they have† (Aristotle 1150). Plots should have a beginning, middle, and end that have a unity of actions throughout the play making it complete. In addi tion, the plot should be complex making it an effective tragedy. The second most important element is character. Characters... ...hough the two demonstrate the elements in different ways, they both achieve an effective tragedy. Now after learning about Aristotle’s philosophy on tragedy, one can examine any type of tragic poetry, play, movie and analysis if the elements are portrayed. Its interesting to see how much of Aristotle’s philosophy has effected poetry in the art of the Greek tragedy, Medea, and the modern movie, No Country for Old Men. Works Cited Aristotle. Poetics. Trans. Gerald F. Else. Ann Arbor: U of Michigan P, 1967. Dorsch, T. R., trans. and ed. Aristotle Horace Longinus: Classical Literary Criticism. New York: Penguin, 1965. Ley, Graham. The Ancient Greek Theater. Chicago: U of Chicago P, 1991. Reinhold, Meyer. Classical Drama, Greek and Roman. New York: Barrons, 1959. Puchner, Martin. The Norton Anthology of World Literature. Vol. A. New York: W.W. Norton &, 2012. Print.

Plc Programmable Logic Controller

AUTOMATIC CONTROL OF HYDRAULIC SYSTEM USING PLC * Company Products & Services * Abstract * Hydraulic System * Bow Compression Machine * Circuit Diagram * Description * Chiller Unit * Solenoid valve * Introduction To PLC * Software * Advantages Of PLC * Introduction To PLC * Existing System * Proposed System * Ladder Logic Diagram * Ladder Logic Description * Energy Saving Calculation * For Existing Method * For Proposed Method * Advantages & Applications * Conclusion * References ABSTRACT :One of the challenging factor in factories, for the proper functioning of the machine for the long duration with efficiency is to keep certain parameters within a specific range. Thus, in this paper, we have designed a ladder diagram for running PLC with the objective to automatically control the hydraulic system. Our main requirement is to design a PLC which can be connected to hydraulic system to implement the parameters and operations like Temperature detection, Pressure detection, Lubrication, Automatic machine operation and Oil level detection.The mentioned parameters and operations can be sensed and operated through PLC without any manual checking and operation. This saves more power to industries by reducing the power consumption. INTRODUCTION In the last decades, the machines used in the industries were operated manually. So keeping its certain important parameters in a specific range was difficult. Also they can not be checked out frequently. This results in improper functioning of the machine. Also, the machines cannot work efficiently for a long time.For example, if the temperature of the oil goes beyond the desired value it will affect the machine function. Hence the machine accessories cannot withstand this high temperature. This leads to the damage in machine and the durability of the machine also gets reduced. Thus, the working machine requires frequent checking of certain parameters to maintain the value within the specified range for proper operation. The var ious parameters to be checked frequently are: 1. Temperature detection 2. Lubrication 3. Automatic machine operation 4. Oil level detection . Pressure Thus we are using a PLC to control all these parameters. We are designing a ladder diagram to control all the parameters automatically. In this paper, we are describing about the hydraulic drive system in which PLC is used to control its working. An introduction of PLC is provided and also the ladder diagram overview. We will be discussing about the advantages of PLC and also the power saving estimation in the industries by using PLC. The machine which we have taken under consideration for implementation is BOW CORRECTION MACHINE.Also, the chiller unit is described as it plays a major role for the power saving purpose. HYDRAULIC DRIVE SYSTEM : A  hydraulic drive system  is a drive or  transmission  system that uses pressurized  hydraulic fluid  to drive  hydraulic machinery. The term hydrostatic refers to the transfer of energy from flow and pressure, not from the  kinetic energy  of the flow. Principle of a hydraulic drive Pascal's law  is the basis of hydraulic drive systems. As the pressure in the system is the same, the force that the fluid gives to the surroundings is therefore equal to pressure ? rea. In such a way, a small piston feels a small force and a large piston feels a large force. For an understanding of how a hydraulic system works, we must know the basic principles, or laws, of hydraulics, that is, of confined liquids under pressure. This will be made easier, however, if we first examine the somewhat simpler laws governing the behavior of liquids when  unconfined, that is, in open containers. 1. Liquids in open containers. a. Density and specific gravity. The first characteristic of an unconfined liquid which interests us is its density.The density of a fluid is the  weight of a unit volume of it. The unit of volume normally used in this text is the cubic foot; the unit o f weight normally used is the pound. The standard of density, to which the densities of all other liquids are referred, is that of pure water at zero degrees centigrade (32 degrees Fahrenheit), and at sea-level atmospheric pressure. b. Force and pressure. A liquid has no shape of its own. It acquires the shape of its container up to the level to which it fills the container. However, we know that liquids have weight.This weight exerts a force upon all sides of the container, and this force can be measured. Therefore, for unconfined liquids, that is, liquids in open containers, the pressure in pounds per square inch exerted by the liquid on the bottom of the container is equal to the weight of the liquid on each square inch of the bottom of the container. It must be emphasized that the  weight  of the liquid is here thought of as a  forceexerted on the bottom of the container. Expressed as a formula, we have: Pressure = Force per unit areaIt is understood that the word pressure , when not otherwise qualified, means  pressure in pounds per square inch. This is called the total force and is obtained by the formula: Total Force = Pressure X Area The pressure exerted by a liquid on the bottom of a container is independent of the shape of the container, and depends only on the height and density of the liquid. 2. Liquids in enclosed systems. a. Liquids are practically incompressible. The following two basic principles will help to explain the behavior of liquids when enclosed: a) Liquids are practically incompressible. ) The applied pressure is transmitted equally in all directions at once. b. Increase of force with area. The ratio between the  force applied to the smaller piston  and the  force applied to the larger piston  is the same as the ratio between the  area of the smaller pistonand the  area of the larger piston. Expressed as a proportion, then, we have: Force on larger piston/Force on smaller piston = Area of larger piston/Area of small er piston This means that the mechanical advantage obtainable by such an arrangement is equal to the ratio between the areas of the two pistons.Since the area of the larger cylinder is 10 times as great as that of the smaller cylinder, pushing the smaller piston downward a distance of 1 inch will move the larger piston upward only 1/10 of an inch. The ratio between the displacement of liquid in the smaller cylinder and the displacement of liquid in the larger cylinder is once again equal to the ratio between their areas. so that the amount of work (force X distance) done by the larger piston is exactly the same as the amount done by the smaller piston. c. Multiple units.It is not necessary to confine our system to a single line from the source of hydraulic power. Hydraulic power may be transmitted in many directions to do multiple jobs. PUMP – In practice we usually need some device which will deliver, over a period of time, a definite volume of fluid at the required pressure , and which will continue to deliver it as long as we desire it to do so. Such a device is called a  pump. Basic principles of pumps. A hydraulic pump is a mechanical device which forcibly moves, or displaces, fluids.Various pumping principles are employed in the different types of hydraulic pumps, but one fundamental principle applies to all: a volume of fluid entering the intake opening, or port, is moved by mechanical action and forced out the discharge port. Hydraulic fluids. Almost any free-flowing liquid is suitable as a hydraulic fluid, as long as it will not chemically injure the hydraulic equipment. For example, an acid, although free-flowing, would obviously be unsuitable because it would corrode the metallic parts of the system. a. Basic units of a hydraulic system. 1.A reservoir, or supply tank, containing oil which is supplied to the system as needed and into which the oil from the return line flows. 2. A pump, which supplies the necessary working pressure. 3. A hydra ulic cylinder, or actuating cylinder, which uses the hydraulic energy developed in the pump to move the door. 4. A cut-out valve, by means of which the pressure in the actuating cylinder may be maintained or released as desired. 5. A check valve, placed in the return line to permit fluid to move in only one direction. 6. â€Å"Hydraulic lines,† such as piping or hose, to connect the units to each other.The supply tank must have a capacity large enough to keep the entire system filled with oil and furnish additional oil to make good the inevitable losses from leakage. The tank is vented to the atmosphere; thus atmospheric pressure (14. 7 pounds per square inch) forces the oil into the inlet, or suction, side of the pump. The tank is generally placed at a higher level than the other units in the system, so that gravity assists in feeding oil into other units. The pump is the hand-operated, reciprocating piston type. SOLENOID VALVE : A  solenoid valve  is an  electromechan ically  operated  valve.The valve is controlled by an  electric current  through asolenoid: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports. Multiple solenoid valves can be placed together on a  manifold. Solenoid valves are the most frequently used control elements in  fluidics. Their tasks are to shut off, release, dose, distribute or mix fluids. They are found in many application areas. Solenoids offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power and compact design.There are many valve design variations. Ordinary valve can have many ports and fluid paths. A 2-way valve, for example, has 2 ports; if the valve is  closed, then the two ports are connected and fluid may flow between the ports; if the valve is  open, then ports are isolated. If the valve is open when the solenoid is n ot energized, then the valve is termed  normally open  (N. O. ). Similarly, if the valve is closed when the solenoid is not energized, then the valve is termednormally closed. [1]  There are also 3-way and more complicated designs.A 3-way valve has 3 ports; it connects one port to either of the two other ports (typically a supply port and an exhaust port). Solenoid valve are also characterized by how they operate. A small solenoid can generate a limited force. If that force is sufficient to open and close the valve, then a  direct acting  solenoid valve is possible. An approximate relationship between the required solenoid force  Fs, the fluid pressure  P, and the orifice areaA  for a direct acting solenoid value is: Where  d  is the orifice diameter. A typical solenoid force might be 15  N (3.   lbf). An application might be a low pressure (e. g. , 10 pounds per square inch (69  kPa)) gas with a small orifice diameter (e. g. ,  3? 8  in (9. 5  mm) fo r an orifice area of 0. 11  sq  in (7. 1? 10? 5  m2) and approximate force of 1. 1  lbf (4. 9  N)). When high pressures and large orifices are encountered, then high forces are required. To generate those forces, an  internally piloted  solenoid valve design may be possible. [1]  In such a design, the line pressure is used to generate the high valve forces; a small solenoid controls how the line pressure is used.Internally piloted valves are used in dishwashers and irrigation systems where the fluid is water, the pressure might be 80 pounds per square inch (550  kPa) and the orifice diameter might be  3? 4  in (19  mm). In some solenoid valves the solenoid acts directly on the main valve. Others use a small, complete solenoid valve, known as a pilot, to actuate a larger valve. While the second type is actually a solenoid valve combined with a pneumatically actuated valve, they are sold and packaged as a single unit referred to as a solenoid valve.Piloted valv es require much less power to control, but they are noticeably slower. Piloted solenoids usually need full power at all times to open and stay open, where a direct acting solenoid may only need full power for a short period of time to open it, and only low power to hold it. A direct acting solenoid valve typically operates in 5 to 10 milliseconds. The operation time of a piloted valve depends on its size; typical values are 15 to 150 milliseconds. Solenoid valves are used in  fluid power  pneumatic and hydraulic systems, to control cylinders, fluid power motors or larger industrial valves.Automaticirrigation sprinkler  systems also use solenoid valves with an automatic  controller. Domestic  washing machines  and  dishwashers  use solenoid valves to control water entry into the machine. Solenoid valves are used in  dentist chairs  to control air and water flow. In the  paintball  industry, solenoid valves are usually referred to simply as â€Å"solenoids. â €  They are commonly used to control a larger valve used to control the propellant (usually compressed air or CO2). In addition to this, these valves are now been used in household water purifiers (RO systems).Besides controlling the flow of air and fluids, solenoids are used in pharmacology experiments, especially for patch-clamp, which can control the application of agonist or antagonist. Many variations are possible on the basic, one-way, one-solenoid valve described above: * one- or two-solenoid valves; * direct current  or  alternating current  powered; * different number of ways and positions; INTRODUCTION TO PLC : A  Programmable Logic Controller, or PLC, is more or less a small computer with a built-in operating system (OS). This OS is highly specialized to handle incoming events in real time, i. . at the time of their occurrence. The PLC has input lines where sensors are connected to notify upon events (e. g. temperature above/below a certain level, liquid level reached, etc. ), and output lines to signal any reaction to the incoming events (e. g. start an engine, open/close a valve, etc. ). The system is user programmable. It uses a language called â€Å"Relay Ladder† or RLL (Relay Ladder Logic). The name of this language implies that the control logic of the earlier days, which was built from relays, is being simulated.The PLC is primarily used to control machinery. A program is written for the PLC which turns on and off outputs based on input conditions and the internal program. In this aspect, a PLC is similar to a computer. However, a PLC is designed to be programmed once, and run repeatedly as needed. In fact, a crafty programmer could use a PLC to control not only simple devices such as a garage door opener, but their whole house, including switching lights on and off at certain times, monitoring a custom built security system, etc.Most commonly, a PLC is found inside of a machine in an industrial environment. A PLC can run an automatic machine for years with little human intervention. They are designed to withstand most harsh environments. When the first electronic machine controls were designed, they used relays to control the machine logic (i. e. press â€Å"Start† to start the machine and press â€Å"Stop† to stop the machine). A basic machine might need a wall covered in relays to control all of its functions. There are a few limitations to this type of control. * Relays fail. * The delay when the relay turns on/off. There is an entire wall of relays to design/wire/troubleshoot. A PLC overcomes these limitations, it is a machine controlled operation. PLCs are becoming more and more intelligent. In recent years PLCs have been integrated into electrical communications  networks  Ã¢â‚¬â€œ i. e. , all the PLCs in an industrial environment have been plugged into a network which is usually hierarchically organized. The PLCs are then supervised by a control center. There exist many propri etary types of networks. One type which is widely known is  SCADA  (Supervisory Control and Data Acquisition).The PLC is a purpose-built machine control computer designed to read digital and analog inputs from various sensors, execute a user defined logic program, and write the resulting digital and analog output values to various output elements like hydraulic and pneumatic actuators, indication lamps, solenoid coils, etc. Scan cycle Exact details vary between manufacturers, but most PLCs follow a ‘scan-cycle' format. Overhead Overhead includes testing I/O module integrity, verifying the user program logic hasn't changed, that the computer itself hasn't locked up (via a watchdog timer), and any necessary communications.Communications may include traffic over the PLC programmer port, remote I/O racks, and other external devices such as HMIs (Human Machine Interfaces). Input scan A ‘snapshot' of the digital and analog values present at the input cards is saved to an i nput memory table. Logic execution The user program is scanned element by element, then rung by rung until the end of the program, and resulting values written to an output memory table. Output scan Values from the resulting output memory table are written to the output modules. Once the output scan is complete the process repeats itself until the PLC is powered down.The time it takes to complete a scan cycle is, appropriately enough, the â€Å"scan cycle time†, and ranges from hundreds of milliseconds (on older PLCs, and/or PLCs with very complex programs) to only a few milliseconds on newer PLCs, and/or PLCs executing short, simple code. ADVANTAGES OF PLC: * PLC’s have flexibility (i. e. ) it is possible to use just one model of PLC to run any one of the 15 machines. * In a PLC program circuit the PLC program can be used from any keyboard sequence in a matter of minute and rewriting is required. PLC has a large number of contacts for each coil in its programming. * I ncreased technology makes it possible to compact move functions into smaller and less expensive packages. * A PLC programmed circuit can be pre-un ad evaluated in the officer or lab. The program can be typed in tested observed and modified if needed. * PLC circuit operation can be seen during operation directly on a CRT screen. * The operation speed for the PLC program is very fast. * PLC is more reliable. * A PLC programmer who works in digital or Boolean control system can easily perform PLC programming. PLC’s program can’t be made unless the PLC properly unlocked and programmed. LADDER LOGIC DIAGRAM : What is a Ladder Diagram? A Ladder Diagram is one of the simplest methods used to program a PLC. It is a graphical programming language evolved from electrical relay circuits. Each program statement is represented with a line, called the rung, that has all relevant inputs to the left and the output to the right. The output device of a rung is energized if electric powe r can conceptually flow from the left side of the rung to the right side.Input devices are assumed to block the flow of power if they are not activated. During the execution of a ladder diagram, the PLC reads the states of all inputs, then determines the states of all outputs starting from the rung at the top side, going down to the last rung, and finally updates the state of the output devices. * Naming Convention During the development of a PLC program, we must use specific names to identify the inputs, outputs, memory flags, timers and counters. PLC manufactures use a variety of approaches in naming the inputs, outputs and other resources.A typical naming convention is to identify inputs with the letter â€Å"I† and outputs with the letter â€Å"O†, followed be a 1-digit number that identifies the slot number and a 2-digit number that identifies the position of the input or output in the slot. For example: I1:00 refers to the first input of slot 1 O2:00 refers to th e first output of slot 2. Some manufactures number the inputs or outputs starting from 00, while others use the number 01 to identify the first input or output. It is also common to use numbers like 400 e. t. c. The state of an output can be also used as an input in a ladder diagram.In such a case the PLC uses the state of the specific output device that is stored in the output image memory. * Relay Logic Instructions (XIC and XIO) Examine if Closed (XIC) —–[ ]—— Use the XIC instruction in your ladder program to determine if a bit is On. When the instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as true. When the instruction is executed, if the bit addressed is off (0), then the instruction is evaluated as false. Examine if Open (XIO) ——-[/]—— Use the XIO instruction in your ladder program to determine if a bit is Off.When the instruction is executed, if the bit addressed is off (0), the n the instruction is evaluated as true. When the instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as false * Relay Logic Instructions: Input Transition Sensing Positive Transition Sense (PTS) The condition of the right link is ON for one ladder rung evaluation when a change from OFF to ON at the specified input is sensed. Negative Transition Sense (NTS) The condition of the right link is ON for one ladder rung evaluation when a change from ON to OFF at the specified input is sensed. * Output Instructions Output Energize (OTE) —-( )—– If the condition of the left link of the OTE is ON then the corresponding bit in the output data memory is set. The device wired to this output is also energized. Negative Output Energize (NOE) ——(/)—– If the condition of the left link of the OTE is OFF then the corresponding bit in the output data memory is set. The device wired output is also energized. Output L atch/Set (OTL) and Output Unlatch/Reset (OTU) If the condition of the left link of the OTL is momentary ON then the corresponding bit in the output data memory is set, and remains set even if the condition switches to the OFF state.The output will remain set until the condition of the left link of the OTU is momentary ON * Basic Logic Functions (OR, AND) Two Input OR Function The output is ON only if the two inputs are OFF. Two Input AND Function The output is ON if both of the two inputs are ON. * Basic Logic Functions (NAND,NOR) Two Input NAND Function The output is ON if any of the two inputs is OFF. Two Input NOR Function The output is ON if both of the two inputs are OFF. * Basic Logic Functions (EXOR, EXNOR) Two Input EXOR Function The output is ON if any of the two inputs is ON, but not both. Two Input EXNOR FunctionThe output is ON if both of the two inputs are either OFF or ON. * Set/Reset Latch Set/Reset Latch using a Hold-in contact Set/Reset Latch using Latch/Unlatch out puts Notes: O1:00’ means that the output is unchanged If both inputs are ON then normally the output is OFF, since the Unlatch rung appears last in the ladder diagram. * Timer Instructions Timer Instructions are output instructions used to time intervals for which their rung conditions are true (TON), or false (TOF). These are software timers. Their resolution and accuracy depends on a tick timer maintained by the microprocessor.Each timer instruction has two values (integers) associated with it: Accumulated Value (ACC): This is the current number of ticks (time-base intervals) that have been counted from the moment that the timer has been energized. Preset Value (PR): This is a predetermined value set by the programmer. When the accumulated value is equal to, or greater than the preset value, a status bit is set. This bit can be used to control an output device. Each timer is associated with two status bits: Timer Enable Bit (EN): This bit is set when the rung condition to t he left of the timer instruction are true.When this bit is set, the accumulated value is incremented on each time-base interval, until it reaches the preset value. Done Bit (DN): This bit is set when the accumulated value is equal to the preset value. It is reset when the rung condition becomes false. * Timer On-Delay (TON) Instruction The TON instruction begins count when its input rung conditions are true. The accumulated value is reset when the input rung conditions become false. Timer ladder diagram example. Typical timing diagram (Assume that Preset = 07). * Timer Off-Delay (TOF) InstructionThe TOF instruction begins count when its input rung makes a true-to-false transition, and continues counting for as long as the input rung remains false. The accumulated value is reset when the input rung conditions become false. Timer ladder diagram example. Typical timing diagram (Assume that Preset = 07). * Retentive Timer (RTO) Instruction The RTO instruction begins count when its input rung conditions are true. The accumulated value is retained when the input rung conditions become false, and continues counting after the input rung conditions become true. * Counter InstructionsCounter Instructions are output instructions used to count false-to-true rung transitions. These transitions are usually caused by events occurring at an input. These counters can be UP (incrementing) or DOWN (decrementing). Each counter instruction has two values (integers) associated with it: Accumulated Value (ACC): This is the current number of the counter. The initial value is zero. Preset Value (PR): This is a predetermined value set by the programmer. When the accumulated value is equal to, or greater than the preset value, a status bit is set. This bit can be used to control an output device.Each counter is associated with two status bits: Counter Enable Bit (EN): This bit is set when a false-to-true rung condition to the left of the counter instruction is detected. Done Bit (DN): T his bit is set when the accumulated value is equal to the preset value. It is reset when the rung condition becomes false. The maximum count value is 9999*. After a maximum count is reached, the counters reset and start counting from zero. * Count-up (CTU) Instruction The CTU instruction increments its accumulated value on each false-to-true transition at its input, starting from 0. Counter ladder diagram example.Typical timing diagram (Assume that Preset = 10). * Count-down (CTD) Instruction The CTD instruction decrements its accumulated value on each false-to-true transition at its input, starting from 0. Counter ladder diagram example. Typical timing diagram (Assume that Preset = -10). * The Reset (RES) Instruction The RES instruction resets timing and counting instructions. When the RES instruction is enabled it resets the following. Counters:Accumulated value, Counter Done Bit , Counter Enabled Bit. Timers: Accumulated value, Timer Done Bit, Timer Timing Bit, Timer Enable Bit.R eset ladder diagram example. ADVANTAGES ; APPLICATION: * Automatic control of machine. * Free from manual operation and frequent checking. * Machine fault is reduced. * Energy consumption is reduced. * This method can save more power. * Industrial application mainly used for boiler production. * Drilling and boring applications. * This applications can be implemented for all machines in BHEL. BOW CORRECTION MACHINE : These are the specifications of the bow correction machine currently in use. MACHINE| BOW CORRECTION MACHINE| CAPACITY| 600 TONS| CYLINDER BORE| 550 MM| RAM DIAMETER| 520 MM|DAYLIGHT| 3000 MM| THROAT| 1700 MM| STROKE| 500 MM| CONNECTED LOAD| 60+1+5 HP| TOTAL WEIGHT| 80 TONS| BOLSTER SIZE| 1500*2000*200 MM| SPEEDS OF OPERATION| 15mm/sec – APPROACH6mm/sec – PRESSING60mm/sec – RETURN | PURPOSE. In the pipes used in boilers, small pipes are attached using welding. This welding makes the pipe to bent. Thus its surface becomes uneven and makes it imperfec t to be used in boilers. In this case this machine is used. Using this machine the bents and bows can be straightened and makes the pipes perfect to be used in the boilers. CIRCUIT DIAGRAM : OPERATION.The hydraulic circuit is designed to achieve fast approach speed, slow pressing speed and fast return speeds by use of a single pump. The fast approach speed is achieved by ensuring that the cylinder ram moves down through its self weight or what is termed as gravity fall. To achieve gravity fall of the cylinder of the cylinder it is important to ensure that at all times the pressure in return line is minimum 5 kg/ cm2. On starting the motor the pump delivery is directed to the tank through unloading type relief valve no. 4. The same flow is directed to the Z1 lines of catridge valves 5 ; 7, which ensures that the valves are closed.On operation of solenoid S1 of main relief valve the pump flow is directed to the catridge valves, however due to differential areas the catridges are still closed and pump reaches system pressure and unloads to tank through relief valve 4. On operation of solenoid S2( valve 6) along with S1, Port A of solenoid valve no. 6 is connected to tank Y1 which facilitates opening of catridge valve 5 and hence the oil flows into the forward line of the cylinder resulting in downward movement. At the same time the oil in the return line of the cylinder is connected to tank at the set pressure through valve no. 11.Hence the cylinder moves down with slow pressing speed. On operation of solenoid S4 ( valve 8) along with S1 ; S2 the X port of catridge valve 10 is connected to tank through valve 8, 6 and port Y1 that ensures the opening of the catridge valve 10. Opening of the catridge valve ensures that the return line is connected directly to tank and hence the cylinder oves down with its self weight and fast approach speed is achieved. At the same time prefill valve 14 opens to fill the cylinder forward area with oil. To set the maximum fast appro ach speed valve 10 is provided with a stroke adjustment setting.On operation of solenoid S3(valve 6) along with S1, port B of solenoid valve no. 6 is connected to tank Y1 which facilitates opening of catridge valve 7 and hence oil flows into the return line of the cylinder. At the same time since A port of solenoid valve no. 6 is connected to pump port X4 is also connected to pump, ensures the opening of prefill valve no 14 and that the forward line of the cylinder is connected back to tank. This results in reverse movement of the cylinder. Pressure relief valve 9 is provided to ensure smooth deceleration of the cylinder from fast approach to pressing.The valve ensures that the pressure in X port of the cartridge valve does not exceed set pressure therby ensuring that the valve closes slowly reducing jerks. The hot oil from the machine is then sent to the chiller unit to reduce its temperature. CHILLER UNIT: In the chiller unit, the refrigerant is used to cool down the hot oil from the machine. REFRIGERATION: A liquid whose Saturation temperature at normal atmospheric pressure is below the temperature that is to be produced by refrigeration is chosen as the working liquid in the refrigerant.Such a liquid will evaporate at lower temperatures and will absorb hear as it does so. This heat is extracted from the surroundings. The vapour formed in this way is compressed in a compressor. After compression the refrigerant may be in the vapour state or, in the liquid state if its temperature after compression is not greater than the saturation temperature at that increase pressure. The low temperature vapour is condensed in a condenser, in doing so it lowers its temperature below the surroundings . Now the condensed liquid is expanded to a lower pressure and the cycle of refrigeration is repeated.REFRIGERATION CYCLE: * Compressors are used in vapour compression cycles. It is the heart of the system and it sucks low-pressure refrigerant vapour from the evaporator and co mpresses it to a pressure corresponding to the saturation temperature that will be higher than continuously re-circulate the refrigerant through the system. * Air-cooled condensers are heat exchangers,which reject heat from the condensing refrigerant to the atmosphere. * The function of condenser in a refrigerated system is to de-superheat and condense the compressed discharge refrigerant vapour.High-speed fans are mostly used to speed up the process. * At the exit of the condenser the refrigerant loses temperature but still is in high-pressure state. The temperature falls down a little high to the ambient. * Dryers are mainly used to capture the moisture content if any mixed with the refrigerant. When the refrigerant passes through its thin filter mesh the moisture gets trapped on the silica gel and clean refrigerant flows through. * Throttle valve(also called as Expansion valve)is also a very important component of the vapour compression refrigeration system.The function of an exp ansion device is to expand the liquid refrigerant from the condensing pressure to the evaporating pressure. Also it throttles the required flow into the evaporator depending on the load conditions. Commonly used expansion devices are capillary tubes, thermostatic expansion valves and constant pressure expansion valves. * Any liquid when evaporate creates a cooling effect. Same applies here, when the refrigerant exists expansion valve it is partly in vapour state at low temperature and pressure. It flows through the evaporator and exchanges heat with the surroundings. After existing the evaporator it has gained heat from the surrounding media, thus lowering the temperature in the freezing compartment. This superhead vapour passes further and is drawn by the compressor, which compresses it,and delivers to condenser, thus, completing the refrigeration cycle. The ladder diagram used in this machine is : CNT_ON CNT_OFF MEM_1 MEM_1 MEM_1 MOT_ON MOT_ON MOT_OFF VAL4_ONVAL4_ON VAL4_ON MEM _2 MEM_2 S1 S2 S3 S4 S5 FAST_APP FAST_APP S1 S2 S3 S4 S5 PRESS_ON TIMER T1 PRESET 15 ACC 0 PRESS_ON S1 S2 S3 S4 S5 HOLD_ON HOLD_ON HOLD_MEM HOLD_MEM S1 S2 S3 S4 S5 RET_ONRET_ON VAL4_ON COMPARE TEMP_ON;45 TEMP_ON MEM_4 MEM_4 CHILLER_ON TEMP_ON CHILLER_OFF COMPARE TEMP_ON;45 LOW_SEN ALARM_ON V_LOW_SEN TANK_ONPRES_ON VAL14_ON EXISTING SYSTEM : * There is no temperature detection system. Hence, the chiller unit has to function continuously irrespective of hydraulic oil’s temperature. * Possibilities of machine can run due to friction since there is no Indication of oil in tank. * The chiller unit is running continuously hence there is a possibilities of lot of Energy consumption losses. * There is no automatic control for the whole machine. * There is no automatic function for declamping and lubrication. There is no oil level sensor in the hydraulic tank to sense the oil level in the tank. * Relays are used which is not automatic and inefficient. HORIZONTAL BORING MACHINE HY DRAULIC TANK CHILLER UNIT PUMP SOLENOID VALVE PROPOSED SYSTEM: * In this method there is a temperature sensor which is used to sense the temperature of the oil in the hydraulic tank. * The chiller unit will be turned on only when the oil temperature gets increased with the specified value of oil temperature * Friction of the machine can be reduced by implementing the lubrication function. Oil level in the hydraulic tank can be detected by using an oil level sensor . * Two types of oil level sensor is used. I. Low level sensor II. Very low level sensor So that we can avoid the machine running in dangerous condition. * All the operation in one axis (x or y or z) can be operated by a single push button switch. * Declamping and lubrication function takes place automatically. ENERGY SAVING CALCULATION: * WITH CHILLER UNIT WORKING CONTINUOUSLY: For continuous running of chiller unit the motor consumes 18KW. Per day: morning -4hrs night -8hrs so chiller unit runs totally 12hrs a day. 8KW*1 2hrs=216 KWhr The chiller unit consumes 216KWhr per day. For electricity: 1unit= Rs. 5 Therefore 216*5= 1080 So for 216 unit it costs Rs. 1080 per day. 1080*30=Rs. 32,400 For 1month it costs Rs. 32,400 32400*303= Rs. 98,17,200 For 1year it costs Rs. 98,17,200. * WITH PLC: For automatic on/off of chiller unit the motor consumes 10KW. Per day: morning -4hrs night -8hrs so chiller unit runs totally 12hrs a day. 10KW*12hrs=120KWhr The chiller unit consumes 120KWhr per day. For electricity: 1unit= Rs. 5 Therefore 120*5= 600 So for 120unit it costs Rs. 600 per day. 600*30=Rs. 8,000 For 1month it costs Rs. 18,000 18000*303= Rs. 54,54,000 For 1year it costs Rs. 54,54,000. CONCLUSION : This project mainly focuses the oil temperature and oil level detection and also the automatic control of machine. Implementation of this project is simple and very economical. This applications can be implemented for all machines in BHEL. All the functions can be achieved through a single PLC program. The adv antage of our project is used to eliminate manual checking and operation. The above mentioned parameters and operation can be sensed and operated through PLC.This project saves more power to industries by reducing the power consumption. REFERENCES : 1. â€Å"Allen bradely Instruction Set user manual† by Rockwell Automation. 2. Programmable Logic Controllers: Programming Methods and Applications by John R. Hackworth and Frederick D. Hackworth, Jr 3. â€Å"Ladder logic fundamentals† industrial control system fall 2006. 4. DOE FUNDAMENTALS HANDBOOK â€Å"INSTRUMENTATION AND CONTROL Volume 2 of 2†- U. S. Department of Energy Washington, D. C. 20585. 5. â€Å"Automating Manufacturing Systems with PLCs† (Version 5. 0, May 4, 2007) -Hugh Jack