Jominy End Essay Example for Free

Jominy End Essay To determine the hardenability of plain carbon steel. Theory Hardenability is the ability of a steel to be hardened and form martensite during quenching. Hardenability indicates the depth of hardness which is obtained from quenching process, and it is very important to the components of machine especially tool steel. One of the methods to determine the hardenability of steels is Jominy End-Quench Test. Hardening usually involves quenching where the steel is heated to austenite phase and fast cooling in the quench medium such as water, oil, salt solution, or air to produce microstructure of martensite. The martensite gives hard and brittle properties of steel. Usually, for heavy steel components, the hardness decreases at the core of component because the microstructure formed is ferrite and pearlite. While at the surface of the component have higher hardness. The difference of the hardness between the core and surface can be explained by Continuous Cooling Transformation or CCT diagram of the steel. If the cooling rate of steel does not cross the transformation curve of the diagram, then the hardness on the whole steel can be obtained. CCT diagrams allow prediction of the final microstructure of the steel taking into account the continuous nature of the process during cooling of austenite. Other than that, CCT diagrams take into consideration continuous cooling during quenching; the cooling curve assumes a constant cooling rate. As we can see from the diagram, martensite form at the temperature below than 200? C, it mean that the specimen with faster cooling rate will able to form more martensite and higher hardness. Continuous Cooling Transformation diagram | | The above diagram show the time-temperature isothermal transformation diagram for the plain carbon steel Apparatus Specimen of plain carbon steel, furnace, Jominy End-Quench Unit, and Vickers Harness Tester. Experimental Procedure (a) Heat the specimen to temperature of 850Â °C and soak at that temperature for 20 minutes. After that, its remain almost constant while the distance increase. In our experiment, there are some test errors where we are having small rise in our reading of the hardenability value which suppose decrease continuously. This is due to the uneven surface of the tested specimen or cause by the unbalanced cooling rate throughout the specimen. (b) Gives your opinion on the correlation between cooling rate of specimen and the graph obtained. The cooling rate at the end of the plain carbon steel are much higher compare to the. Thus, in the graph it shows the highest hardness at the early stage and then slowly decreases when approaching to the core of the steel. We also can say that, at the end of the steel has the highest hardness which cause by the high content of martensite. However, the content of the martensite and hardness will drop when approaching to the centre of the steel. We can conclude that the cooling rate decreases from the end-quench to the centre of the steel, resulting in decreasing of the hardness.

Free Essays on The Crucible: John Proctor :: Essay on The Crucible

The Crucible - John Proctor, a man with pride John Proctor plays the leading role in The Crucible by Arthur Miller. He was persistent, honest, and full of integrity. He was simply, a man with pride. A wise woman once said, "Do what you feel in your heart to be right--for you'll be criticized anyway. You'll be damned if you do, and damned if you don't." (Eleanor Roosevelt). Proctor was the protagonist of the dramatic piece of literature. When the play sets in to action, John has had a past affair with his servant Abigail Williams. His wife, Elizabeth Proctor is very forgiving of his sin, but John has his mind set that he will not confess to anyone else, in fear of ruining his good name, and reputation. The affair between John and Abigail caused the start of chaotic witchery and accusation. After the affair, Abigail became horribly jealous of Elizabeth Proctor. Proctor realizes there is only one way to stop all the witch hysteria in Salem, and that would be to confess his sin of adultery. Although he knows he should, he continues to be determined not to confess. Also in the beginning Reverend Paris is new to town, and John insist continually that he is only speaking of hell, and hardly ever of God, as Proctor goes on to say to Parris, "Can you speak one minute without we land in Hell again? I am sick of Hell!" (Miller 30). In the drama, Mary Warren places a needle in a poppet she gave to Elizabeth; John fi rmly demands that Mary Warren tell the courts that she really put the needle in the poppet that day. Proctor says to her, "You're coming to the court with me, Mary. You will tell it in the court." (Miller 80). Furthermore, at the end of the play Proctor is persistent by saying that no matter what anyone says to convince him differently, he would rather die an honest man and save his name. John Proctor took pride in his thoughts, feelings, values, and his name. It took persistency to make his intent clear to others. For many reasons, John Proctor is an honest man. By no means is Proctor afraid to tell you what is on his mind.

Pitfalls in executive information systems (EIS) development

As identified by Watson, EIS failures are due to the following factors: Lack of executive support – The support during the period of development is very essential. The support from the higher management with regard to information transparency and belief for the system would define better activity lifecycle and speed in implementation. Often information gathering from higher management is poorly managed and lacks standard processes for recording mechanism.As not enough documentation is done, the primary stage of IS development is miscarried and entire lifecycle suffers. Undefined system objectives – The system objectives are often revised and requirements are poorly defined. The scope of such systems is open and is never seized, thereafter making the system development in an undefined fashion. The system objective is not understood from the very beginning. The idea is to determine and set right goals for the system. Such initiatives are often neglected and not documented well.Undefined goals push activities to a different path and lack enough direction to succeed (McNurlin, 2009). Inadequate support staff – The support staff are often inadequate and unskilled to handle the development. The high skill individuals are often lacking for the development of EIS, which demands effective resources with years of aligned experience. Such shortages pose a danger to the development. Improper planning – The planning of the EIS system development is often is not adequate and lacks risk management information.The idea is to make the right judgment of the system in conjunction with various organizational objectives and the scope of the system. Such analysis often lacks and thus the system development fails. Planning the EIS system into various sub-systems for development makes the system development planned, however often the system knowhow makes it quite difficult to understand the entire system and thus the development of framework becomes difficu lt. References McNurlin B. C. and Sprague R. H. (2009). Information Systems Management in Practice (8th Ed). Prentice Hall.

The Legacy of Catholicism as Practiced by African Americans

The Haitian Revolution (1791-1803) and the accompanying slave revolt transplanted many refugees from the revolution into North America. Both former slaves and free people of color began to arrive in cities like Baltimore and New Orleans in the late eighteenth century and early nineteenth century. The Maryland Gazette published an announcement of â€Å"six ships [one a Guineaman, with negroes] four brigs, and four schooners, being part of the fleet which sailed from Cape Francois on the 23d ultimo. The passengers and crews amount to 619 persons†¦Ã¢â‚¬  The blacks on board the Guineaman would become the center of the black religious community that was established in the â€Å"chapelle basse† or lower chapel of St. Mary’s Seminary. It was this black†¦show more content†¦Our people should help her to do it. Mary Elizabeth Lange and the Oblate Sisters of Providence In 1829 the Haitian community, which met in the lower chapel of St. Mary’s Seminary in Baltimore, produced the first black American religious community. Mary Elizabeth Lange born circa 1800 in Cuba to Haitian parents arrived in the Baltimore areas sometime after 1817. Lange enlisted the aid of three other women, all of African descent, and began teaching the black children of the community. Jacques Joubert, a French Sulpician priest, was given the task of the religious education of the children of the free, French speaking people of color. His sole purpose of teaching the children of color to read was so that they could recite the catechism, however in the black community’s vision, this education could serve as the solution for overcoming the trials of the black American experience. In 1827 Joubert initiated the Holy Family Society, a lay organization, to support the spiritual growth of Baltimore black Catholics. The priest formed this project among the immigrant black French speaking Haitians of Baltimore just as Lange was already running her own school. Not wanting to alarm anyone with the establishment of an official religious society of women of color, Joubert carefully put in the constitution that the women of color would not make vows but simply make a promise of obedience. The Oblate Sisters of Providence formed the firstShow MoreRelatedA Study Of African History1384 Words   |  6 PagesWest Africa, but little do they know African Americans were trading themselves way before then. Portuguese explorer Prince Henry, known as the navigator, was the first European to methodically explore Africa and the oceanic to the Indies.[1] Many Europeans thought that Africa s history was not important. They argued that Africans were inferior to Europeans and they used this to help justify slavery. However, the reality was very different. 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