The layout and operation of a piston engine Assignment

The layout and operation of a piston engine - Assignment Example 1. Stationery parts These include all parts that hold the engine in place and resist the motion of the entire structure due to moments created by the dynamic moving parts. Source: Griffiths Denis, 1997 It also houses the jackets for the cylinder cooling system and the sump for storing the engine lubricating oil. Some of these parts include (i) Bed Plate- The main functions of the bedplate includes providing a support for the main engine bearing and provides a cover space for the lower portion of the crankcase. The sump for the lubricating oil is also contained in this area. (Anderson Henrik, 2007) (ii) Main Bearings- This supports the crankshaft and takes up the load that is transmitted from the piston onto the crankshaft. Explosions or unequal generation of torque can affect the bearing severely which can be easily replaced thus preventing replacement of the entire crankshaft.( Calder Nigel, 1987) Source: RTA84T Sulzer Engine, 2004 (iii) Frame- This houses the entire upper portion o f the crankcase and provides stability to the cylinder block. In marine engines these are also referred to as the ‘A’ Frame. ... ource: RTA84T Sulzer Engine, Liner 2004 (vi) Cylinder Heads- This is the top portion of the cylinder liner and seals the liner thus creating a confined space required for combustion. (vii) Valves or Ports- The function of valves or ports is to allow the entry of fresh air required for combustion and to allow the exit of exhaust gas after the combustion is over. Valves are an additional entity usually housed on top of the cylinder head while ports are holes and openings situated on the cylinder liner which open or close according to the position of the piston skirt with respect to the cylinder liner. (Calder Nigel, 1987) 2. Moving Parts (i) Piston- The face of the piston acts as the other end of the confined space in which combustion occurs. The piston slides in and out of the cylinder contributing to each stroke of the engine. To prevent metal to metal contact between the liner and the piston sides a small clearance is maintained; the sealing achieved by a number of sealing rings hou sed in grooves at the upper end of the piston. The sealing ring prevents the air or exhaust gas from passing on to the underside of the piston. The bottom end of piston is called the ‘skirt’ while the upper portion is called the ‘crown’. Source:RTA84T Sulzer Engine,Pistons, 2004 (ii) Connecting rod- The connecting rod can be construed as a bar which has bearings at both ends. It acts as an interface between the piston and the crankshaft. The thrust developed on the piston is transmitted to the crankshaft via the connecting rod. (Anderson Henrik, 2007) (iii) Connecting Rod Bolts- The connecting rod connected to the crankpin of the crankshaft has a split bottom end. This split end is held in place by these bolts. (iv) Crankshaft- The reciprocating motion of the piston in the cylinder

Future Solutions to HIV AIDS :: Biology Disease

Introduction to HIV What is HIV? First Things First: What is HIV? The Human Immunodeficiency Virus (HIV) is one of the most evasive viruses that the medical world has to experience. We use the word evasive because HIV targets the CD4 cells (T-helper cells), which are the exact cells that are used to protect your body against diseases. Once HIV enters the body, it will infect the CD4 cells and begin to use those cells as its own â€Å"HIV factory.† HIV will therefore begin to destroy your immune system leaving you susceptible to opportunistic diseases. HIV targets your immune system... What does HIV infect and how? HIV affects your immune system. Your immune system can be thought of as your body’s defense line! In which, you have millions of 'soldiers' (T-helper cells) helping you ward off almost any foreign invaders. Now, it is important to note that just like in a army defense line, your body also has different levels of protection. Introduction to HIV Cont. Your skin is the first line of defense... †¢ First line of defense: the skin o Your skin is an amazing organ, which helps you ward off invaders from the outside. Special cells called Dendritic cells and macrophages are white blood cells that try to fight off infection before it becomes a major problem. T-Cells of the humoral immune response are the second line of defense... †¢ Second line of defense: T-Cells o Once a virus has invaded the body, T-Cells (CD4 cells) relay signals to the rest of the immune system, which causes the immune system to activate by sending out the â€Å"reinforcements.† These T-killer cells (CD8 cells) do exactly what the name suggests, they â€Å"kill† almost any foreign invader, through apoptosis or programmed cell death. Other CD4 activated cells are part of your body's line of defenses... †¢ Other Cells activated by CD4 Cells o B-Cells- Once activated, B-cells / Plasma cells begin producing antibodies against a virus o Natural Killer Cells (NK)- Help your body by destroying infected cells Introduction to HIV Cont. All viruses must be able to bind to a cell in order to enter it. In the case of HIV, the virus has a cell membrane with embedded viral proteins that enables it to do so, but this works only when it binds with two specific receptors. One is called the main receptor, and the other a coreceptor. There are two types of HIV; M-tropic and T-tropic. The M-tropic variant targets macrophages while the T-tropic variant targets the T cells. Future Solutions to HIV AIDS :: Biology Disease Introduction to HIV What is HIV? First Things First: What is HIV? The Human Immunodeficiency Virus (HIV) is one of the most evasive viruses that the medical world has to experience. We use the word evasive because HIV targets the CD4 cells (T-helper cells), which are the exact cells that are used to protect your body against diseases. Once HIV enters the body, it will infect the CD4 cells and begin to use those cells as its own â€Å"HIV factory.† HIV will therefore begin to destroy your immune system leaving you susceptible to opportunistic diseases. HIV targets your immune system... What does HIV infect and how? HIV affects your immune system. Your immune system can be thought of as your body’s defense line! In which, you have millions of 'soldiers' (T-helper cells) helping you ward off almost any foreign invaders. Now, it is important to note that just like in a army defense line, your body also has different levels of protection. Introduction to HIV Cont. Your skin is the first line of defense... †¢ First line of defense: the skin o Your skin is an amazing organ, which helps you ward off invaders from the outside. Special cells called Dendritic cells and macrophages are white blood cells that try to fight off infection before it becomes a major problem. T-Cells of the humoral immune response are the second line of defense... †¢ Second line of defense: T-Cells o Once a virus has invaded the body, T-Cells (CD4 cells) relay signals to the rest of the immune system, which causes the immune system to activate by sending out the â€Å"reinforcements.† These T-killer cells (CD8 cells) do exactly what the name suggests, they â€Å"kill† almost any foreign invader, through apoptosis or programmed cell death. Other CD4 activated cells are part of your body's line of defenses... †¢ Other Cells activated by CD4 Cells o B-Cells- Once activated, B-cells / Plasma cells begin producing antibodies against a virus o Natural Killer Cells (NK)- Help your body by destroying infected cells Introduction to HIV Cont. All viruses must be able to bind to a cell in order to enter it. In the case of HIV, the virus has a cell membrane with embedded viral proteins that enables it to do so, but this works only when it binds with two specific receptors. One is called the main receptor, and the other a coreceptor. There are two types of HIV; M-tropic and T-tropic. The M-tropic variant targets macrophages while the T-tropic variant targets the T cells.

Database Design P1, M1 & D1 Essay

Database is a place to store lots of data, imagine it as a giant virtual filling cabinet that can be organized in many ways. There’s software called (DBMS) which stands for database management system which allows the user to manage data in database such as; create, delete or update. Entities Entities are objects with significant mass and purpose, in database entities are tables. Every table contains many fields/attributes. The user must create a table before inputting any data. When creating a table you need to define a few things, data type, fields name & a description. Fields Name This is a column heading, this will display the title for the column etc first name, last name, address. Data Type This is the content of the data & the data type decides what content can be inputted & the file size. Description This is used to explain the content & shows a list of ‘limitations’ the user can change to get a more accurate reading etc. input mask. Attributes A characteristic, for example; a field has many attributes such as data like numbers or letters. Attributes can be used as a synonym for a â€Å"field†. In DOS systems, each files has an attribute, each file has many properties that shows if the file is â€Å"read only†, visible or encrypted. Queries A query is use for searching some specific record. It allow user to set conditions and then search the record which match the conditions. User also is able to make the search mix up with other table and sort the order of the result. Reports A Report is a summary of record. Everything you plain to print should put inside. Its purpose is for user to view information quickly and easily so display the result simply and efficiently is the main point. Forms Form is used for collect and edits information and transfers them to table. It is similar to application forms that allow user to fill in or delete their data easily and it also able to let user design own user interface. User can insert as much control as they like to build the user interface beautifully. Relationships Relationship types Database relationships are very similar in that they’re associations between tables. There are three types of relationships: One-to-one: both tables of the relationship have one field that matches up, for example; a married couple that both have a child that has no relation to the other partner. This rarely ever happens in a business organization One-to-many: one-to-many is where one table has none/one or many relations with the other table’s fields but the other table has only none/one field. For example, you have only one mother, but your mother may have several children. Many-to-many: Both tables have one/many relations to each other’s fields. Usually in this instance there are usually 3 tables. Benefits The benefits of having databases online are that it’s easier & quicker to do. The amount of paper saved & room is very beneficial. Its quicker & easier for the user to find important data in the database. The user can make forms to find & read information easier. The user can set rules to make the data input more accurate & legit. You can save the information on multiple storage units (hard drives) So if the information has been tampered with, there’s always a spare copy somewhere safe. Task 2 Primary key The primary key of a relational table uniquely identifies each attribute in the table. Primary keys could be a unique attribute such as â€Å"social security number† for a person or student etc. Primary keys may consist of a single attribute or multiple attributes in combination. Primary keys connect tables together in relationships Referential integrity There is a feature with databases called relational database management systems (RDBMS’s) that prevents users or applications from entering inconsistent data. Most RDBMS’s have referential integrity rules that you can apply when you create a relationship between two entities. For example, suppose Table B has a foreign key that points to a field in Table A. Referential integrity would prevent you from adding a record to Table B that cannot be linked to Table A. In addition, if I deleted a attribute in table A, if it is linked to table B, the data that is connecting both attributes will be deleted. This is called cascading delete. Finally, the referential integrity rules could specify that whenever you modify the value of a linked field in Table A, all records in Table B that are linked to it will also be modified accordingly. This is called cascading update. D1: Analyse Potential Errors in the Design & Construction of a Database and explain how these can be avoided There are many common errors that could occur while using database, it’s important to understand how these common error happen & what causes them. Deletion of records & fields Deleting important records & fields happen quite commonly, it’s caused by the user or by accident. If this does happen its always safe to know there is a copy of the data saved somewhere else in case this happens. It’s good to have a refresh back up time for 1 hour so every hour, the data renews itself. Human error leads to corruption or loss of fields so to ensure this doesn’t happen it would be best to set administrative rights to the right users so only the right people can edit or delete fields, if the wrong people try to use the database, an error or password will be shown. Making more than 1 copy of the data is wise just in case something happens to the first copy. Incorrect data types To decrease the chances of getting incorrect data types in database, its best to put input masks on the fields. This stops incorrect data being imputed on data forms like sign-up sheets. It’s also wise to have multiple choice questions & drop down menus; this makes it more accurate to get correct data. Using drop down menus makes it easier & quicker for the user to get a positive & effective data results. By using the drop down menus & multiple choice questions, it ensures correct spelling & grammar of important information. Validation To ensure the data is imputed clean & correct you need to use validation rules. This is done by setting rules in the design view where the user can set what data can be imputed & what is invalid. An effective tool is the â€Å"limit checker† where the user can set a limit to the amount of characters that can be imputed into the database. Range checks are effective to ensure etc. birthdays, it sets the month from 1-12 & has a set range to when the  person was born etc. 1950-2014 (we are currently on 2014 so I don’t need to extend the range). Grammar checks are there to make sure the data isn’t misspelt, it also makes personal information & letters easier to produce. There’s a rule that can be set up on database that checks the inputted data for any incorrect information, if it finds something wrong, an error message will pop up & notify the user. Null Values Null values is similar to validation in where the user needs to input data & there are a set of rules to ensure the user inputs the correct/legitimate data however null values are shown when no data has been inputted into a specific textbox. An error message will pop up if no data is put into a specific field, this rule is usually put on by the user as when starting database, you get a lot of blank fields. This rule is useful for fields that need data in them such as â€Å"personal details†, â€Å"bank details† etc. If the user doesn’t type in anything into the textbox & clicks â€Å"accept† or â€Å"enter† an error message will pop up notifying the user about the null values. The boxes with errors are marked differently to the textboxes without errors, this is to clearly identify where the error is & makes its easier & quicker for the user to resolve.

Persuasive Essay Racism - 1958 Words

America the Great or America the Racist? In middle school, I remember getting into an argument with a white girl over a brown color pencil. I planned on letting her have it, until she called me the N- word and told me, â€Å"Go back to Africa!† At that time, my class was half white, and they thought it was hilarious, hi-fiving each other and laughing. The other side looked at her shocked until she called them the N- word also, and all hell broke loose. We learned about racism in the past, but in 2013, but we never thought we would experience it. Racism is discrimination or discrimination against another race , from one that believes that their race is superior. One of the biggest debates in America is whether or not racism exist. Racism is†¦show more content†¦African Americans make up 12% of the U.S. population, but they make up 40% of the of all prison inmates and 42% of those sentenced to death (Costly, 1). Even though African Americans make up less than 15% of the population, we take up four-tenths of th e prison population for crimes whites commit and get probation for. Minorities are the majority that are institutionalized and are treated the worst. The graph above is from a study conducted by U.S. Sentencing Bureau in 2004. I am going to be using this graph and the paragraph above to show how the disparity changes in a course of about 6 years. In 2004, blacks made up 15% of the population and about 47% of the prison population. In 2010, they only made up 12% of the population and about 42% of the prison population. The population of blacks have went down and so has the incarceration rates because police are more likely to shoot blacks than to actually try arrest them. Some police officers claim to fear for their lives when arresting a black male because they do not know whether or not they will try to kill them so most officers just shoot. Racism is present in American and our justice system proves it everyday. The U.S. Bureau of Justice Statistics reported that black boys are five times and Latino boys are nearly three times as likely as white boys to go to jail (Quigley, 1). Blacks are more likely to be targeted than Latino’s, Latina s are more likely to be targetedShow MoreRelatedPersuasive Essay On Racism1138 Words   |  5 Pages It was during the first week of INT that I started to feel more in depth with the racism and its different terms. We talked in detail on intent, reverse racism, and white supremacy after watching few videos for each matter. It turned out that there are deeper meaning and context to these terms than the mere definition. A number of cases regarding intent have suggested that it’s solely up to someone’s motives if they are being racist or not. For instance, we talked in class about this one teacherRead MorePersuasive Essay On Racism1654 Words   |  7 Pageshas still not been accomplished. People get judged on their skin color and many other things all the time and it isn’t right. Not everybody of the same race, or religion, or sexual orientation are all the same. Racism is a horrible, horrible thing that many people in America experience. Racism and slavery go back many, many years ago. All the way back starting in the 17th century. Since then we have had the Trail of Tears during President Jackson’s presidency when he threw the Native Americans off theirRead MorePersuasive Essay On Racism1271 Words   |  6 Pagesthe options to chose our race. Yet we are still being ridiculed from what we are born with. Racism is one of many elements that in the United States of Americ a affects our society. However, there is a hidden problem that promotes racism. It is the fact that a lot of people try to make themselves believe that racism doesn t exist. But unfortunately, it still does. Everyone knows about the problem of racism but don t realize that they are supporting the problem by discriminating against other peopleRead MorePersuasive Essay On Racism701 Words   |  3 PagesRacism Racism is an issue in America that has been growing, Martin Luther King was a famous black citizen for his bravery of black people as equals. We can respond to and eradicate racism only through a peaceful stand for the love for humanity. The call of Pope Francis to take â€Å" a clear stand for creative and active nonviolence and against all forms of violence† echoes the Reverend Dr. Martin Luther King’s dream of a nation without racism. Inspired by Dr. King’s concept of a creative and constructiveRead MorePersuasive Essay On Racism882 Words   |  4 Pagesword to me, eventually I have come to understand her intentions during that week. Little did I know that this would not be the last time I would endure a situation like this. ‘Subtle Racism’ in America is common in society. It can come from all sides, and can have as deep an effect as blatant racism. Subtle racism to me is shown from someone who may not consider themselves to be racist, and may see themselves as a supporter of all ethnicities, but expresses certain behaviors and phrases that canRead MorePersuasive Essay On Racism1018 Words   |  5 Pagesit s working at 7/11, always smelling like curry, or mocking us with our thick accents. Stereotypes have always been around, they have been used to make some funny jokes, but others have used it personally and criticize people with it. That is why racism is a big problem in this world with people using stereotypes to verbally attack people, thinking those things are true for every race and not getting to know people before judging them. My friends always turn to these jokes when they want to makeRead MorePersuasive Essay On Racism1317 Words   |  6 Pages Is America Racist? As a privileged white female in the United States, I don’t personally deal with any racism. But millions of Americans are impacted by racism on a daily basis. They are exposed to ignorant slurs and racial violence constantly. Some people say that not everyone is America is racist. That America as a whole is accepting and welcoming. If so, why did we elect a president whose immigration policies will limit entry of millions of non-white people into our country? How is itRead MorePersuasive Essay On Racism1926 Words   |  8 Pagesdifferent culture or has different skin color? Racism is the major issues today and it still exists in our schools, works, and society. Racism at the workplace is responsible for continuous mood changes, aggressive behavior, and have a bad feeling in the minds of the affected persons. This turn bad for the employer and the society. Everyone has right to do something so why do people become races. Today it was better than years ago but still, racism exists in the United States and other countriesRead MorePersuasive Essay On Racism1752 Words   |  8 PagesRacism is contagious to this society. It has been a growing concern in the United States for many decades now, however, no major improvements are made by any political officials in reducing it. Many individuals of color are treated unfairly just because they are of pigment. Not too long ago, many individuals in the African American communities sparked out in outrage when individuals such as Michael Brown and much more were racially profiled by were brutally attacked by the law enforcers. Racism doesRead MorePersuasive Essay On Racism1839 Words   |  8 PagesThroughout America, racism is a very prominent topic that affects thousands of American’s. Although racism has been fought for many of years in America, Americans find themselves still talking about the social divide. The subject of racism is all over the news and has even made it’s way to America’s game, football. The kneeling during the national anthem has been a very big controversy that many American’s are furious about. However, for black Americans, it is an outcry that should be heard. Many