A mechanical filter is a signal processing filter usually used in place
of an electronic filter at radio frequencies to allow a range of signal
frequencies to pass, but to block others. The filter acts on mechanical
vibrations. Transducers at the input and output of the filter convert
the electrical signal into, and then back from, these mechanical
vibrations. The mechanical elements obey mathematical functions which
are identical to their corresponding electrical elements. Electrical
theory has developed a large library of mathematical forms that produce
useful filter frequency responses for use in the design of mechanical
filters. Steel and nickel–iron alloys are common materials for
mechanical filter components. Resonators in the filter made from these
materials need to be machined to precisely adjust their resonance
frequency prior to final assembly. The high "quality factor", Q, that
mechanical resonators can attain, far higher than that of an
all-electrical LC circuit, made possible the construction of mechanical
filters with excellent selectivity. Good selectivity, being important
in radio receivers, made such filters highly attractive. Contemporary
researchers are working on microelectromechanical filters, the
mechanical devices corresponding to electronic integrated circuits.
Read the rest of this article:
<http://en.wikipedia.org/wiki/Mechanical_filter>
_______________________________
Today's selected anniversaries:
1905:
In a sign of support for the December Uprising in Moscow, the Council
of Workers' Deputies of Kiev decided to stage a mass uprising,
establishing the Shuliavka Republic in the city.
<http://en.wikipedia.org/wiki/Shuliavka_Republic>
1946:
The United Nations General Assembly created UNICEF, originally to help
provide emergency food and health care to children in countries that
had been devastated by World War II.
<http://en.wikipedia.org/wiki/UNICEF>
1962:
Arthur Lucas, convicted of murder, was the last person to be executed
in Canada.
<http://en.wikipedia.org/wiki/Capital_punishment_in_Canada>
1981:
About 900 civilians in El Salvador were killed in the El Mozote
massacre.
<http://en.wikipedia.org/wiki/El_Mozote_massacre>
2008:
American stock broker Bernard Madoff was arrested and charged with
securities fraud in a $50 billion Ponzi scheme, the largest such in
history.
<http://en.wikipedia.org/wiki/Bernard_Madoff>
_____________________________
Wiktionary's word of the day:
undownable (adj):
1. Undeniably important; describing that which cannot be played down or
ignored.
2. Invincible; describing that which cannot be brought down or
overcome
<http://en.wiktionary.org/wiki/undownable>
___________________________
Wikiquote quote of the day:
If only there were evil people somewhere insidiously committing evil
deeds, and it were necessary only to separate them from the rest of us
and destroy them. But the line dividing good and evil cuts through the
heart of every human being. And who is willing to destroy a piece of
his own heart?
--Aleksandr Solzhenitsyn
<http://en.wikiquote.org/wiki/Aleksandr_Solzhenitsyn>
The Exelon Pavilions are four structures which generate electricity
from solar energy and provide access to underground parking in
Millennium Park in the Loop community area of Chicago in Cook County,
Illinois, US. The pavilions provide sufficient energy to power the
equivalent of 14 Energy star-rated energy-efficient houses in Chicago.
The four pavilions, which cost $7 million, were designed in January
2001; construction began in January 2004. The South Pavilions were
completed and opened in July 2004, while the North Pavilions were
completed in November 2004, with a grand opening on April 30, 2005. In
addition to producing energy, three of the four pavilions provide
access to the parking garages below the park, while the fourth serves
as the park's welcome center and office. Exelon, a company that
generates the electricity transmitted by its subsidiary Commonwealth
Edison, donated $5.5Â million for the pavilions. Chicago Tribune
architecture critic Blair Kamin praised the South Pavilions as "minor
modernist jewels", but criticized the North Pavilions as "nearly all
black and impenetrable". The North Pavilions have received the
Leadership in Energy and Environmental Design (LEED) silver rating from
the United States Green Building Council, as well as an award from the
American Society of Heating, Refrigerating and Air-Conditioning
Engineers.
Read the rest of this article:
<http://en.wikipedia.org/wiki/Exelon_Pavilions>
_______________________________
Today's selected anniversaries:
1684:
Edmond Halley presented the paper De motu corporum in gyrum, containing
Isaac Newton's derivation of Kepler's laws from his theory of gravity,
to the Royal Society.
<http://en.wikipedia.org/wiki/De_motu_corporum_in_gyrum>
1898:
Forces led by Nguyen Trung Truc, an anti-colonial guerrilla leader in
southern Vietnam, sank the French lorcha L'Esperance.
<http://en.wikipedia.org/wiki/Nguyen_Trung_Truc>
1907:
During the Brown Dog affair, about 1,000 protesters marched through
London and then clashed with 400 police officers in Trafalgar Square
over the existence of a memorial for animals which have been
vivisected.
<http://en.wikipedia.org/wiki/Brown_Dog_affair>
1936:
Edward VIII of the United Kingdom, out of a desire to marry American
socialite Wallis Simpson against widespread opposition, abdicated the
royal throne, the first and only British monarch to have done so since
the Anglo-Saxon period.
<http://en.wikipedia.org/wiki/Edward_VIII_abdication_crisis>
1979:
The Kuomintang (KMT) dictatorship of Taiwan arrested a larger number of
opposition leaders who had organized pro-democracy demonstrations, an
incident credited with ending the KMT's rule in 2000.
<http://en.wikipedia.org/wiki/Kaohsiung_Incident>
_____________________________
Wiktionary's word of the day:
intempestivity (n):
Unseasonability; untimeliness
<http://en.wiktionary.org/wiki/intempestivity>
___________________________
Wikiquote quote of the day:
We despise and abhor the bully, the brawler, the oppressor, whether in
private or public life, but we despise no less the coward and the
voluptuary. No man is worth calling a man who will not fight rather
than submit to infamy or see those that are dear to him suffer wrong.
--Theodore Roosevelt
<http://en.wikiquote.org/wiki/Theodore_Roosevelt>
John Lennon (1940–1980) was an English musician and singer-songwriter
who achieved worldwide fame as a founding member of The Beatles, one of
the most commercially successful and critically acclaimed acts in the
history of popular music. Born and raised in Liverpool, Lennon had a
rebellious nature and acerbic wit, and at 16-years-old, formed a
skiffle group which evolved into The Beatles in 1960. With bandmate
Paul McCartney, he established the Lennon/McCartney songwriting
partnership, which provided the bulk of the Beatles' catalogue until
they dissolved at the end of the decade. Lennon then embarked on a solo
career that produced the critically acclaimed albums John
Lennon/Plastic Ono Band and Imagine. He became controversial through
his work as a peace activist; his iconic songs, "Give Peace a Chance"
and "Imagine", were adopted as anthems of the anti-war movement. With
his wife and muse Yoko Ono, he moved to New York City in 1971, where
his criticism of the Vietnam War resulted in a lengthy attempt by
Richard Nixon's administration to deport him. He took a sabbatical from
the music business in 1975 to devote time to his family, reemerging in
1980 with a new album, Double Fantasy, but was murdered on December 8,
three weeks after its release.
Read the rest of this article:
<http://en.wikipedia.org/wiki/John_Lennon>
_______________________________
Today's selected anniversaries:
1432:
Lithuanian Civil War: The first battle between the forces of
Švitrigaila and Sigismund Kęstutaitis was fought near the modern town
of Ashmyany.
<http://en.wikipedia.org/wiki/Lithuanian_Civil_War_%281431%E2%80%931435%29>
1609:
Milan's Biblioteca Ambrosiana opened its reading room to the public,
becoming the second public library in Europe.
<http://en.wikipedia.org/wiki/Biblioteca_Ambrosiana>
1963:
After being hit by a lightning strike while in a holding pattern, Pan
Am Flight 214 crashed near Elkton, Maryland, USA, killing all 81 people
on board.
<http://en.wikipedia.org/wiki/Pan_Am_Flight_214>
1998:
The Australian Cricket Board's cover-up of Shane Warne and Mark Waugh's
involvement with bookmakers was revealed.
<http://en.wikipedia.org/wiki/John_the_bookmaker_controversy>
2004:
Twelve South American countries signed the Cusco Declaration,
announcing the foundation of what is now the Union of South American
Nations, an intergovernmental union modelled after the European Union.
<http://en.wikipedia.org/wiki/Union_of_South_American_Nations>
_____________________________
Wiktionary's word of the day:
John Lennon glasses (n):
A pair of eyeglasses (spectacles) with round lenses
<http://en.wiktionary.org/wiki/John_Lennon_glasses>
___________________________
Wikiquote quote of the day:
I am not bound over to swear allegiance to any master; where the storm
drives me I turn in for shelter.
--Horace
<http://en.wikiquote.org/wiki/Horace>
Daniel Lambert (1770–1809) was a gaol keeper and animal breeder from
Leicester, England, famous for his unusually large size. He was a keen
sportsman and extremely strong, on one occasion fighting a bear in the
streets of Leicester. He was an expert in sporting animals, widely
respected for his expertise on dogs, horses and fighting cocks. In 1805
the gaol of which Lambert was keeper closed. By this time he weighed
50Â stone (700Â lb; 320Â kg), and had become the heaviest authenticated
person in recorded history up to that time. Unemployed and sensitive
about his bulk, he became a recluse. Poverty forced Lambert to put
himself on exhibition to raise money, and in April 1806 he moved to
London, charging spectators to enter his apartments to meet him.
Visitors were impressed by his intelligence and personality, and
visiting him became highly fashionable. After a few months, Lambert
returned wealthy to Leicester and soon began making short fundraising
tours. In June 1809 he died suddenly in Stamford. At the time of his
death he weighed 52Â stone 11Â lb (739Â lb; 335Â kg). It took 20 men almost
half an hour to drag his casket into the trench in the burial ground at
St Martin's Church. Though no longer the heaviest person in history,
Daniel Lambert remains a popular character in Leicester.
Read the rest of this article:
<http://en.wikipedia.org/wiki/Daniel_Lambert>
_______________________________
Today's selected anniversaries:
1869:
American outlaw Jesse James committed his first confirmed bank robbery
in Gallatin, Missouri.
<http://en.wikipedia.org/wiki/Jesse_James>
1936:
Australian cricketer Jack Fingleton became the first player to score
centuries in four consecutive Test innings.
<http://en.wikipedia.org/wiki/Jack_Fingleton>
1941:
World War II: The Imperial Japanese Navy made its surprise attack on
Pearl Harbor in Hawaii, intending to neutralize the United States
Pacific Fleet from influencing the war Japan was planning to wage in
Southeast Asia.
<http://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor>
1949:
Chinese Civil War: The government of the Republic of China relocated
from Mainland China to Taipei on the island of Taiwan.
<http://en.wikipedia.org/wiki/Taipei>
2007:
A crane barge that had broken free from a tugboat crashed into an oil
tanker near Daesan, South Korea, causing the country's worst-ever oil
spill.
<http://en.wikipedia.org/wiki/2007_Korea_oil_spill>
_____________________________
Wiktionary's word of the day:
animadversion (n):
A criticism; a critical remark
<http://en.wiktionary.org/wiki/animadversion>
___________________________
Wikiquote quote of the day:
There are some things you learn best in calm, and some in storm. You
learn the delivery of a part only before an audience.
--Willa Cather
<http://en.wikiquote.org/wiki/Willa_Cather>
Rock Steady is the fifth album by American rock band No Doubt, released
December 11, 2001, on Interscope Records. The band began writing the
album with initial recording sessions in Los Angeles and San Francisco,
then traveled to London and Jamaica to work with various performers,
songwriters, and producers. Sly & Robbie, The Neptunes, and William
Orbit were among the many artists the band collaborated with on the
album. As a result of the many collaborations, Rock Steady touches on
many musical styles. The album focuses more on dub, synthpop, and dance
styles. The band attempted to capture the vibe of Jamaican dancehall
music, and experimented with writing songs without its standard
instrumentation. Singer Gwen Stefani wrote her lyrics quickly in
comparison to previous records, and dealt with topics ranging from
partying to ruminations on her relationship with Gavin Rossdale. Rock
Steady received mostly positive reviews from music critics, and it was
nominated for Best Pop Vocal Album at the 45th Grammy Awards. The album
served as a commercial comeback for the band, surpassing sales of its
previous offering, Return of Saturn, released in 2000. Rock Steady
spawned four singles, two of which won the Grammy Award for Best Pop
Performance by a Duo or Group with Vocal.
Read the rest of this article:
<http://en.wikipedia.org/wiki/Rock_Steady_%28album%29>
_______________________________
Today's selected anniversaries:
1590:
Niccolò Sfondrati became Pope Gregory XIV, succeeding Pope Urban VII
who died two months earlier.
<http://en.wikipedia.org/wiki/Pope_Gregory%C2%A0XIV>
1791:
Wolfgang Amadeus Mozart died without completing his Requiem mass in D
minor.
<http://en.wikipedia.org/wiki/Requiem_%28Mozart%29>
1945:
Flight 19, a squadron of five U.S. naval TBF Avenger torpedo bombers,
disappeared in the area now known as the Bermuda Triangle.
<http://en.wikipedia.org/wiki/Flight_19>
1972:
Gough Whitlam took office as the 21st Prime Minister of Australia and
formed a duumvirate with his deputy Lance Barnard, ending 23 years of
Liberal-Country Party government.
<http://en.wikipedia.org/wiki/Gough_Whitlam>
1974:
The Birmingham Americans won the only World Bowl in World Football
League history.
<http://en.wikipedia.org/wiki/Birmingham_Americans>
_____________________________
Wiktionary's word of the day:
consternation (n):
Amazement or horror that confounds the faculties, and incapacitates for
reflection; terror, combined with amazement
<http://en.wiktionary.org/wiki/consternation>
___________________________
Wikiquote quote of the day:
Faith I have, in myself, in humanity, in the worthwhileness of the
pursuits in entertainment for the masses. But wide awake, not blind
faith, moves me. My operations are based on experience, thoughtful
observation and warm fellowship with my neighbors at home and around
the world.
--Walt Disney
<http://en.wikiquote.org/wiki/Walt_Disney>
Pedro II (1825–1891) was the second and last ruler of the Empire of
Brazil, reigning for over 58 years. Born in Rio de Janeiro, he was the
seventh child of Emperor Dom Pedro I of Brazil and Empress Maria
Leopoldina and thus a member of the Brazilian branch of the House of
Braganza. His father's abrupt abdication and flight to Europe in 1831
left a five-year-old Pedro as Emperor and led to a grim and lonely
childhood and adolescence. Obliged to spend his time studying in
preparation for rule, he knew only brief moments of happiness and
encountered few friends of his age. His experiences with court
intrigues and political disputes during this period greatly affected
his later character. Pedro II grew into a man with a strong sense of
duty and devotion toward his country and his people. On the other hand,
he increasingly resented his role as monarch. Inheriting an empire on
the verge of disintegration, Pedro II turned Brazil into an emerging
power. The nation grew to be distinguished from its Hispanic neighbors
on account of its political stability, zealously-guarded freedom of
speech, respect for civil rights, vibrant economic growth and
especially for its form of government: a functional, representative
parliamentary monarchy.
Read the rest of this article:
<http://en.wikipedia.org/wiki/Pedro_II_of_Brazil>
_______________________________
Today's selected anniversaries:
1763:
The Touro Synagogue, the oldest surviving Jewish synagogue building in
North America, was formally dedicated.
<http://en.wikipedia.org/wiki/Touro_Synagogue>
1804:
The coronation of Napoleon I of France was held at Notre Dame
Cathedral in Paris.
<http://en.wikipedia.org/wiki/Coronation_of_Napoleon_I>
1823:
U.S. President James Monroe issued the Monroe Doctrine, a proclamation
of opposition to European colonialism in the New World.
<http://en.wikipedia.org/wiki/Monroe_Doctrine>
1956:
Cuban Revolution: The yacht Granma, carrying Fidel Castro, Che Guevara
and 80 other members of the 26th of July Movement, reached the shores
of Cuba.
<http://en.wikipedia.org/wiki/Granma_%28yacht%29>
2008:
Thai political crisis: The Constitutional Court of Thailand dissolved
three political parties, including the governing People's Power Party,
leading to the resignation of Prime Minister Somchai Wongsawat.
<http://en.wikipedia.org/wiki/Somchai_Wongsawat>
_____________________________
Wiktionary's word of the day:
sententious (adj):
1. (obsolete) Full of meaning.
2. Using as few words as possible; pithy and concise.
3. Tending to
use aphorisms, especially given to trite moralizing
<http://en.wiktionary.org/wiki/sententious>
___________________________
Wikiquote quote of the day:
I do think that if I had to choose one word to which hope can be tied
it is hospitality. A practice of hospitality— recovering threshold,
table, patience, listening, and from there generating seedbeds for
virtue and friendship on the one hand — on the other hand radiating out
for possible community, for rebirth of community.
--Ivan Illich
<http://en.wikiquote.org/wiki/Ivan_Illich>
The Clemuel Ricketts Mansion is a Georgian style house made of
sandstone, built in 1852 or 1855 on the shore of Ganoga Lake in Colley
Township, Sullivan County, Pennsylvania, in the United States. It was
home to several generations of the Ricketts family, including R. Bruce
Ricketts and William Reynolds Ricketts. Originally built as a hunting
lodge, it was also a tavern and post office, and served as part of a
hotel for much of the 19th century. After 1903 the house served as the
Ricketts family's summer home, they kept it even as they sold over
65,000Â acres (26,000 ha) to the state of Pennsylvania from 1920 to
1950. The house was included in the Historic American Buildings Survey
in 1936 and listed on the National Register of Historic Places in 1983.
The original mansion is an L-shaped structure, two-and-a-half stories
high, with stone walls 2Â feet (0.6 m) thick. It was built in a clearing
surrounded by old-growth forest with a view to the lake 900Â feet (270
m) to the east. In 1913 a two-and-a-half story wing was added to the
north side of the house and the original structure was renovated. The
house has twenty-eight rooms, four porches, and its original hardware
and woodwork. Dormers and some windows were added in the renovation,
and electrical wiring and modern plumbing have been added since.
According to the NRHP nomination form, the Clemuel Ricketts Mansion "is
a stunning example of Georgian vernacular architecture".
Read the rest of this article:
<http://en.wikipedia.org/wiki/Clemuel_Ricketts_Mansion>
_______________________________
Today's selected anniversaries:
1833:
The Parliament of the United Kingdom abolished slavery throughout most
of the British Empire, with the exceptions of Ceylon, Saint Helena, and
the territories owned by the East India Company.
<http://en.wikipedia.org/wiki/Slavery_Abolition_Act_1833>
1913:
The Buenos Aires Metro in Argentina, the first underground railway
system in the Southern Hemisphere and in Latin America, began
operations.
<http://en.wikipedia.org/wiki/Buenos_Aires_Metro>
1934:
Soviet politician Sergey Kirov was assassinated at the Smolny
Institute in Leningrad.
<http://en.wikipedia.org/wiki/Sergey_Kirov>
1955:
African-American Civil Rights Movement: Seamstress Rosa Parks was
arrested for violating the racial segregation laws of Montgomery,
Alabama, after refusing to give up her seat on a public bus to a white
man, precipitating the Montgomery Bus Boycott.
<http://en.wikipedia.org/wiki/Rosa_Parks>
1990:
Channel Tunnel workers from the United Kingdom and France met 40Â metres
(131 ft) beneath the English Channel seabed.
<http://en.wikipedia.org/wiki/Channel_Tunnel>
_____________________________
Wiktionary's word of the day:
hebetude (n):
Mental lethargy or dullness
<http://en.wiktionary.org/wiki/hebetude>
___________________________
Wikiquote quote of the day:
The AIDS crisis is evidence of a world in which nothing important is
regional, local, limited; in which everything that can circulate does,
and every problem is, or is destined to become, worldwide.
--Susan Sontag
<http://en.wikiquote.org/wiki/Susan_Sontag>