Lead

Lead (/lɛd/) is a chemical element in the carbon group with symbol Pb (from Latin: plumbum) and atomic number 82. It is a soft, malleable and heavy post-transition metal. Freshly cut, solid lead has a bluish-white color that soon tarnishes to a dull grayish color when exposed to air; the liquid metal has shiny chrome-silver luster. Lead is the heaviest (has the highest atomic number) non-radioactive element (two radioactive elements, namely technetium and promethium, are lighter), although the next higher element, bismuth, has one isotope with a half-life that is so long (over one billion times the estimated age of the universe) that it can be considered stable. Lead's four stable isotopes each have 82 protons, a magic number in the nuclear shell model of atomic nuclei. The isotope lead-208 also has 126 neutrons, another magic number, and is hence double magic, a property that grants it enhanced stability: lead-208 is the heaviest known stable nuclide.

Lead is used in building construction, lead-acid batteries, bullets and shot, weights, as part of solders, pewters, fusible alloys, and as a radiation shield.

Cutoff (steam engine)

In a steam engine, cutoff is the point in the piston stroke at which the inlet valve is closed. On a steam locomotive, the cutoff is controlled by the reversing gear.

The point at which the inlet valve closes and stops the entry of steam into the cylinder from the boiler plays a crucial role in the control of a steam engine. Once the valve has closed, steam trapped in the cylinder expands adiabatically. The steam pressure drops as it expands. A late cutoff delivers full steam pressure to move the piston through its entire stroke, for maximum start-up forces. But, since there will still be unexploited pressure in the cylinder at the end of the stroke, this is achieved at the expense of engine efficiency. In this situation the steam will still have considerable pressure remaining when it is exhausted resulting in the characteristic “chuff chuff” sound of a steam engine. An early cutoff has greater thermodynamic efficiency but results in a lower Mean effective pressure so less average force on the piston and is used for running the engine at higher speeds. The steam engine is the only thermodynamic engine design that can provide its maximum torque at zero revolutions per minute.

Lead (electronics)

In electronics, a lead is an electrical connection consisting of a length of wire or metal pad (SMD) that comes from a device. Leads are used for physical support, to transfer power, to probe circuits (see multimeter), to transmit information, and sometimes as a heatsink. The tiny leads coming off through-hole components are also often called pins.

Many electrical components such as capacitors, resistors, and inductors have only two leads where some integrated circuits (ICs) can have several hundred leads to more than a thousand for the largest BGA devices. IC pins often either bend under the package body like a letter "J" (J-lead) or come out, down, and form a flat foot for securing to the board (S-lead or gull-lead).

Most kinds of integrated circuit packaging are made by placing the silicon chip on a lead frame, wire bonding the chip to the metal leads of that lead frame, and covering the chip with plastic. The metal leads protruding from the plastic are then either "cut long" and bent to form through-hole pins, or "cut short" and bent to form surface-mount leads. Such lead frames are used for surface mount packages with leads—such as small-outline integrated circuit (SOIC), Quad Flat Package (QFP), etc. -- and for through-hole packages such as dual in-line package (DIP) etc. -- and even for so-called "leadless" or "no-lead" packages—such as quad-flat no-leads package (QFN), etc.

Lead (disambiguation)

Lead has two different pronunciations and several different meanings, usually related to either the chemical element lead (a heavy metal) or the verb to lead.

When pronounced /ˈlɛd/ (rhymes with "bed")

With this pronunciation, "lead" refers to:

The past tense of the verb to lead is led, pronounced /ˈlɛd/. It is often misspelled as lead.

See also:

When pronounced /ˈliːd/ (rhymes with "need")

With this pronunciation, "lead" generally means "first", "ahead", or "guide":

Lead (band)

Lead is a Japanese hip-hop group, under the Record of Pony Canyon/ Flight Master. Their debut was on July 31, 2002 with their single Manatsu no Magic (Mid-Summer Magic).

Biography

Hiroki Nakadoi, Shinya Taniuchi, and Akira Kagimoto all attended Osaka's "Caless Vocal and Dance School" and became good friends. By March 2002, they began doing live street performances, on the streets of Shiroten, Osaka; under the dance unit name of "remix". By May 2002, they renamed the group from "remix" to "flow". After having the name change, the three decided to recruit a fourth member.

Meanwhile, on April 13, 2002 - the "Kyushu/Fukuoka Starlight Audition" was held in Okinawa, Japan on a search for new talent. At the time, thirteen-year-old Keita Furuya and another contestant were declared winners out of the 8,751 hopefuls that had auditioned. Flow tracked down Keita and he soon joined the now four member group "flow" as of May 18, 2002.

On May 23, 2002 - The group underwent another and final name change, officially becoming "Lead", as they hoped to become a leading group of the age.

News style

News style, journalistic style or news writing style is the prose style used for news reporting in media such as newspapers, radio and television.

News style encompasses not only vocabulary and sentence structure, but also the way in which stories present the information in terms of relative importance, tone, and intended audience. The tense used for news style articles is past tense.

News writing attempts to answer all the basic questions about any particular event—who, what, when, where and why (the Five Ws) and also often how—at the opening of the article. This form of structure is sometimes called the "inverted pyramid", to refer to the decreasing importance of information in subsequent paragraphs.

News stories also contain at least one of the following important characteristics relative to the intended audience: proximity, prominence, timeliness, human interest, oddity, or consequence.

The related term journalese is sometimes used, usually pejoratively, to refer to news-style writing. Another is headlinese.