Alloy Definition and Examples in Chemistry

An alloy is a substance made by melting two or more elements together, at least one of them metal. An alloy crystallizes upon cooling into a solid solution, mixture, or intermetallic compound. The components of alloys cannot be separated using a physical means. An alloy is homogeneous and retains the properties of a metal, even though it may include metalloids or nonmetals in its composition. Alternate Spellings: alloys, alloyed Alloy Examples Examples of alloys include stainless steel, brass, bronze, white gold, 14k gold, and  sterling silver. Although exceptions exist, most alloys are named for their primary or base metal, with an indication of other elements in order of mass percent. Uses of Alloys Over 90% of metal used is in the form of alloys. Alloys are used because their chemical and physical properties are superior for an application than that of the pure element components. Typical improvements include corrosion resistance, improved wear, special electrical or magnetic properties, and heat resistance. Other times, alloys are used because they retain the key properties of component metals, yet are less expensive. Example Alloys Steel: the name given to an alloy of iron with carbon, usually with other elements, such as nickel and cobalt. The other elements add a desired quality to the steel, such as hardness or tensile strength.Stainless Steel: another iron alloy, which typically contains chromium, nickel, and other elements to resist rust or corrosion.18k Gold: this is 75% gold. The other elements typically include copper, nickel, or zinc. This alloy retains the color and luster of pure gold, yet is harder and stronger, making it better suited for jewelry.Pewter: an alloy of tin, with other elements such as copper, lead, or antimony. The alloy is malleable, yet stronger than pure tin, plus it resists the phase change of tin that can make it crumble at low temperatures.Brass: a mixture of copper with zinc and sometimes other elements. Brass is hard and durable, making it suitable for plumbing fixtures and machined parts.Sterling Silver: is 92.5% silver with copper and other metals. Alloying silver makes it h arder and more durable, although the copper tends to lead to greenish-black oxidation (tarnish).Electrum: Some alloys, like electrum, occur naturally. This alloy of silver and gold was highly prized by ancient man.Meteoritic Iron: While meteorites may consist of any number of materials, some are natural alloys of iron and nickel, with extraterrestrial origins. These alloys were used by ancient cultures to make weapons and tools.Amalgams: These are mercury alloys. The mercury makes the alloy much like a paste. Amalgams may be used in  dental fillings, with the mercury intact, although another use is to spread the amalgam and then heat it to vaporize the mercury, leaving a coating of another metal.

Essay about Uganda - 1984 Words

Uganda 1. Historical background The country known as Uganda was once a British colony just like the majority of its neighbors in East Africa. It was initially intruded into by the Arab traders led by Speke and the British explorers led by Stanley in 1862 and 1875 respectively. They both paid homage to Mutesa who was the King (kabaka) of the Buganda. Uganda remained predominantly under the colony of the British until 1962 when they were granted internal self government by Britain (History World, 2011). Uganda is a country that covers 7,108 sq mi in area and a host of 33.3 million people found in East Africa. It is bordered by Congo on the West, Kenya on the East, Tanzania and Rwanda on the south and Sudan on the North. It†¦show more content†¦Malaria is another disease that is predominant as well as the water borne diseases. Some of the most emerging and re-emerging agents of the waterborne diseases are; Cholera which is caused by the ingestion of water that is infected by Vibrio Cholerae. This is a painless form of diarrhea characterized by watery stool. Dysentery which is caused by Escherichia Coli. Typhoid that is caused by Salmonella typhi which is usually accompanied by fever is yet another disease. Gastroenteritis diseases caused by Giardia and Cryptosporodia and some species of hepatitis are also known to be caused by water (CDC, 2011). These disease causing agents find their way into the human body through infected water that people from the poorer communities in Uganda use and have no option of cleaner water. Some of the measures that the government has encouraged to help curb the problem is boiling of water. This is the cheapest option since the government cannot afford offering iodine tablets and the water filters. The Uganda Red Cross Society has also done its best during every outbreak of cholera like the severe 2006 incidence where more than 300,000 people within the capital city of Kampala were affected directly by the cholera pandemic (Disaster Relief Emergency Fund, 2008). However, this is treatment and not a preventive measure. Even so, this cheapest optionShow MoreRelatedA Brief Note On Uganda And Uganda Are Neighbours892 Words   |  4 PagesIntroduction: Kenya and Uganda are neighbours. They are all within East Africa together with Tanzania, Rwanda, Burundi and South Sudan. Even though they are within the same region; their development status in agriculture, industrialization, democracy, health, and education economies differ greatly. Discussion: Uganda: Uganda has considerably natural resources. These include fertile soils, regular rainfall, small deposits of copper, gold, and other minerals, and recently they discovered oil. 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Mobile Phone and Broadband Network Free Essays

StarHub is Singapore’s fully-integrated info-communications company, offering a full range of information, communications and entertainment services for both consumer and corporate markets. StarHub operates a HSPA+ mobile network that delivers up to 42Mbps for downlink to complement its nationwide GSM network, and an LTE network that provides connection speeds of up to 75Mbps in key business areas. It also manages an island-wide HFC network that delivers multi-channel pay TV services (including HDTV, Internet TV and on-demand services) as well as ultra-high speed residential broadband services. We will write a custom essay sample on Mobile Phone and Broadband Network or any similar topic only for you Order Now StarHub operates an extensive fixed business network that provides a wide range of data, voice and wholesale services. Over Singapore’s fibre-based Next Generation Nationwide Broadband Network, StarHub offers a broad range of home and business broadband plans along with a host of advanced media-rich value-added services. Launched in 2000, StarHub has become one of Singapore’s most innovative info-communications providers, and the pioneer in ‘hubbing’ – the ability to deliver unique integrated and converged services to all its customers. StarHub, listed on the main board of the Singapore Exchange since October 2004, is a component stock of the Straits Times Index and the MSCI Singapore Free Index. Personal Solutions Mobile * Innovative price plans that include cost-saving features such as Free Incoming Local Calls, Per Second Billing, Flat Roaming Rates, All Day Flat Calling Rate, and Free IDD 018 Calls to 18 destinations * Green Pre-paid service * BlackBerry service, the world’s leading secure wireless email platform * Mobile broadband service delivered over StarHub’s 4G and 3. G network * Mobile data service offers a price cap for data access packages, so customers can surf with peace-of-mind from the mobile phone * StarHub TV on Mobile service that streams pay TV channels including National Geographic Channel and CNN over StarHub’s advanced mobile broadband network * Home Zone, a 3G femtocell service which allows customers to make mobile calls at home through their broadband cable connection * International Roaming service to more than 230 destinations * StarHub is a member of the Conexus Mobile Alliance, which was formed to enhance member’s ompetitiveness in international roaming and corporate mobile services in their own counties and across Asia Pacific. It is now Asia’s largest alliance of mobile operators with a coverage footprint to over 350 million subscribers in more than 12 countries and regions pfingo pfingo (short for phone, freedom, Internet, on the go) is a VoIP service developed by StarHub. pfingo enables users to make and receive local and overseas calls from their computer or SIP-enabled mobile phones at low rates, regardless of the mobile or broadband network users are connected to. The pfingo account is free and calls between pfingo users are also free. Other rich features that pfingo offers include SMS, fax, free push email (Google Mail, Yahoo! Mail, or any POP3 email services), multi-headed chat (Yahoo! Messenger, Google Chat, Windows Live Messenger, ICQ Chat), and foreign number services. For as little as S$2/month, pfingo users enjoy the use of a 3-series Singapore phone number with free incoming calls. To find out more, visit  www. pfingo. com Wireless Broadband StarHub Wireless Broadband is available at Suntec Convention Centre and certain areas of Suntec Retail Mall, Singapore Expo, all The Coffee Bean ; Tea Leaf outlets, as well as selected areas in Changi Airport Terminals 1, 2 and 3 * StarHub customers enjoy free wireless broadband access at all StarHub hotspots in Singapore. In addition, they can get free access to Wireless@SG services through a Memorandum of Understanding reached between StarHub and QMax Communications. As a pioneer member of the Wireless Broadband Alliance, StarHub together with other member operators, has been driving the adoption of wireless broadband technologies and services around the world by developing a common commercial, technical and marketing framework for wireless network interoperability. StarHub has enabled wireless broadband international roaming capabilities in Australia, Japan, Malaysia, UK, the USA and more. IDD StarHub’s IDD offerings include the StarHub IDD 008 and 018 services, HomeConnect (pre-paid IDD card) and the StarHub International Calling Card (post-paid IDD card) * StarHub’s post-paid and pre-paid mobile customers enjoy free IDD 018 calls to 18 selected destinations. Home Solutions Pay TV * StarHub is Singapore’s largest pay TV operator, offering a full suite of quality international channels of news, movies, entertainment, sports, music and education, and seven local free-to-air channels. StarHub’s digital platform allows customers to enjoy interact ive applications and advanced features. * Operates the Digital Terrestrial Television (DTTV) system which offers better quality service and a compelling selection of channels for corporate customers. * Offers Southeast Asia’s first commercial High Definition Television (HDTV) service. Currently carries six HD Channels. * Offers Demand TV and Internet TV Residential Broadband * MaxOnline, StarHub’s cable modem service is the first â€Å"always-on†, unlimited broadband Internet access plan launched in Singapore. Offers MaxInfinity fibre broadband service, offering download speeds of up to 1Gbps * Offers Anytime TV which allows customers to access StarHub TV’s on-demand library of more than 6,500 TV shows and movies as well as 12 complimentary pay-TV channels. Residential Voice * Digital Voice, a personal fixed line voice service that is delivered over StarHub’s broadband network. * For a low monthly subscription fee, customers can enjoy outgoing/inco ming local calls for free. Online Value-added Services Online music portal * Email service * Content filtering service * Online storage service Business Solutions StarHub offers a host of services for businesses of every size. We customise our solutions to meet our customers’ needs, and help them stay ahead of the competition. Our services include: Business Voice ; IDD * StarHub IDD 008, StarHub IDD 018, domestic and international ISDN, business voice services, fixed number related services, and domestic toll-free services (1800 services) Data Services Ethernet Leased Line (ELL), Switched Ethernet (SWE), Super Direct Service (SDS), Domestic Leased Circuit (DLC), International Ethernet Private Line (IEPL), International Private Leased Circuit (IPLC) IP/Internet Services * Business Broadband (ADSL and Enterprise Web), Business Internet (Internet Leased Line), IP Transit Service (Velocity and StarHub IP Exchange/SiX), Switched Ethernet IP Services (SWE), Internet Clean Pipe, Onl ine Storage – Business Global Managed Services * Arcstar Global Managed Services, BT Global Managed Services StarHub Global Conferencing Services StarHub Global Conferencing Services International Wholesale Voice Services * Carriers around the world, as well as Service-Based and Facilities-Based Operators in Singapore, use StarHub’s International Wholesale Voice service to help them reach the destinations they need via StarHub’s established international interconnections. Logo The StarHub identity is an expression of our intention to be a proactively innovative company. We want to do things differently, to enhance customer choices for info-communications services and therefore, their quality of life. We recognise that the world in which we live in is changing rapidly, and in order to enable our customers to get the most out of life and their choice of communications services, StarHub will have to explore new horizons and broaden our perspective. Our visual identity is a positive expression of this goal. It recognises people as individuals and that everyone has the power to change for the better. It is confident, forward-looking and dynamic as expressed by the vibrant colours. The transition from Blue to Green, emphasizes the transformation that we want to bring to people’s lives through innovative and integrated info-communications solutions. StarHub’s corporate logo embodies the essence of a Chinese proverb which when translated means â€Å"green is derived from blue and green will become more brilliant than blue†; in short, the pupil shall surpass the teacher. Like the star depicted in its corporate identity, StarHub will adopt a dynamic and forward-looking stance, poised to transform the industry landscape and service mindset in a brand new way. Culture StarHub Vision To be Singapore’s first choice for information, communications and entertainment services. StarHub Mission To provide every person, home and business in Singapore with world-class multimedia services and content StarHub Core Values ExCITe : Excellence, Creativity, Integrity, Teamwork. 2010 Milestones November * Introduced Singapore’s first solar-powered mobile base station enabled vehicle. September * Introduced a broad range of home and business broadband plans along with a host of advanced media-rich value-added services over Singapore’s fibre-based Next Generation Nationwide Broadband Network. July Adopted world’s first smartphone signalling solution to further enhance network performance and improve end-user smartphone experience. * Launched Singapore’s first full DRM-free unified music store. May * Made available Singapore’s first microSIM card to support compatible mobile devices. * Scored broadcast rights to the 2010 FIFA World Cup. Ma rch * Commenced HSPA+ network upgrade to support up to 42. 2Mbps on the downlink. January * Launched new mobile TV client to enhance TV viewing on smartphones. * Partnered Golden Village and launched Singapore’s first movie-ticketing service on television. How to cite Mobile Phone and Broadband Network, Papers