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Supreme Court's Obamacare decision established new limits on federal authority, IU paper says

Supreme Court's Obamacare decision established new limits on federal authority, IU paper says


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31-Oct-2013



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Contact: George Vlahakis
vlahakis@iu.edu
812-855-0846
Indiana University





BLOOMINGTON, Ind. -- A new paper by an Indiana University professor sheds new light on the U.S. Supreme Court's rejection of legal challenges to the Affordable Care Act, which many critics said threatens state sovereignty and individual liberties.


The paper comes at a time when problems with the act's implementation, particularly the creation of state health care exchanges, highlight the limits of federal capabilities and the importance of state cooperation in the success of domestic government programs.


In an article in Business Horizons, a journal published by IU's Kelley School of Business, Tim Lemper argues that the court's decision in National Federation of Independent Business v. Sebelius actually established new limits on the power of the federal government.


"The court was heavily criticized for betraying the principles of federalism and limited government in the U.S. Constitution," Lemper said. "In reality, the court's decision placed groundbreaking limits on Congress' power to regulate commerce and use federal funds to pressure states into doing its bidding.


"These aspects of the court's decision received less attention in the popular media but may actually prove to have a more significant impact on the scope of federal power in the future," said Lemper, a clinical professor of business law at Kelley.


In his research, Lemper often takes a more critical approach to overlooked details in legislation and jurisprudence. Earlier research brought to light a drafting error in the federal trademark dilution statute, which led Congress to amend the law last fall.


In his paper, "The Supreme Struggle: 'Obamacare' and the New Limits on Federal Regulation," Lemper bases his arguments on two points raised in the court's opinion: new limits on Congress' power to regulate interstate commerce and to coerce states with the threat of losing federal funding.


In his majority opinion, Chief Justice John Roberts explained that the limits on Congress' power in the Constitution, and the reservation of powers to the states, were intended to protect individual liberty.


Details overlooked in media reports about the decision include what Justice Ruth Bader Ginsburg, in dissent, called "a novel constraint" on Congress' power to regulate interstate commerce, a sweeping and seemingly unlimited power that has been used to uphold a broad range of federal regulations on activity far beyond traditional commercial transactions, Lemper said.


"Set in historical context, the court's decision is significant because it establishes a new limit on Congress' expansive power under the Commerce Clause," he wrote. "Five of the nine justices concluded that the Commerce Clause gives Congress the power to regulate existing commercial activity, but does not allow Congress to compel individuals to become active in commerce.


"In other words, Congress can regulate activity under the Commerce Clause, but it cannot regulate inactivity."


Applying this rationale to the Affordable Care Act, the majority on the court concluded that the individual mandate (requiring individuals to buy health insurance or pay a tax penalty) exceeded Congress' power to regulate commerce because it compelled people to engage in commerce by buying health insurance.


"That the court still upheld the individual mandate as a valid exercise of Congress' more limited power to lay and collect taxes does not diminish the significance of the limit that it placed on Congress' more expansive power to regulate interstate commerce," Lemper said. "Congress' power to lay and collect taxes is more limited and less coercive than its power to regulate interstate commerce, which -- before this decision -- increasingly appeared to have no limit."


"The court's decision precludes Congress from venturing into new regulatory territory under the guise of regulating commerce," he said. "At the very least, it forecloses future governmental regulation that uses a person's inaction as a basis to compel them to act."


Lemper said the court's decision also broke new ground in restricting Congress' power under the Spending Clause. Seven of the justices -- "a majority of rare size for this court" -- held that the Affordable Care Act wrongly coerced states into accepting the Medicare expansion by threatening them with the loss of all Medicare funding (a significant portion of states' budgets) if they refused to do so.


"The court's decision is remarkable because it is the first time that the court has ever struck down a federal law under the Spending Clause on the ground that it runs counter to the system of federalism in the Constitution," he added. "For decades, the court has recognized the possibility that the federalism principles could limit Congress' power under the Spending Clause, but it had never actually done so until its decision on the Affordable Care Act.


"Its landmark holding gives real teeth to limits on Congress' power that had previously only existed in theory."



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Supreme Court's Obamacare decision established new limits on federal authority, IU paper says


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PUBLIC RELEASE DATE:

31-Oct-2013



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Contact: George Vlahakis
vlahakis@iu.edu
812-855-0846
Indiana University





BLOOMINGTON, Ind. -- A new paper by an Indiana University professor sheds new light on the U.S. Supreme Court's rejection of legal challenges to the Affordable Care Act, which many critics said threatens state sovereignty and individual liberties.


The paper comes at a time when problems with the act's implementation, particularly the creation of state health care exchanges, highlight the limits of federal capabilities and the importance of state cooperation in the success of domestic government programs.


In an article in Business Horizons, a journal published by IU's Kelley School of Business, Tim Lemper argues that the court's decision in National Federation of Independent Business v. Sebelius actually established new limits on the power of the federal government.


"The court was heavily criticized for betraying the principles of federalism and limited government in the U.S. Constitution," Lemper said. "In reality, the court's decision placed groundbreaking limits on Congress' power to regulate commerce and use federal funds to pressure states into doing its bidding.


"These aspects of the court's decision received less attention in the popular media but may actually prove to have a more significant impact on the scope of federal power in the future," said Lemper, a clinical professor of business law at Kelley.


In his research, Lemper often takes a more critical approach to overlooked details in legislation and jurisprudence. Earlier research brought to light a drafting error in the federal trademark dilution statute, which led Congress to amend the law last fall.


In his paper, "The Supreme Struggle: 'Obamacare' and the New Limits on Federal Regulation," Lemper bases his arguments on two points raised in the court's opinion: new limits on Congress' power to regulate interstate commerce and to coerce states with the threat of losing federal funding.


In his majority opinion, Chief Justice John Roberts explained that the limits on Congress' power in the Constitution, and the reservation of powers to the states, were intended to protect individual liberty.


Details overlooked in media reports about the decision include what Justice Ruth Bader Ginsburg, in dissent, called "a novel constraint" on Congress' power to regulate interstate commerce, a sweeping and seemingly unlimited power that has been used to uphold a broad range of federal regulations on activity far beyond traditional commercial transactions, Lemper said.


"Set in historical context, the court's decision is significant because it establishes a new limit on Congress' expansive power under the Commerce Clause," he wrote. "Five of the nine justices concluded that the Commerce Clause gives Congress the power to regulate existing commercial activity, but does not allow Congress to compel individuals to become active in commerce.


"In other words, Congress can regulate activity under the Commerce Clause, but it cannot regulate inactivity."


Applying this rationale to the Affordable Care Act, the majority on the court concluded that the individual mandate (requiring individuals to buy health insurance or pay a tax penalty) exceeded Congress' power to regulate commerce because it compelled people to engage in commerce by buying health insurance.


"That the court still upheld the individual mandate as a valid exercise of Congress' more limited power to lay and collect taxes does not diminish the significance of the limit that it placed on Congress' more expansive power to regulate interstate commerce," Lemper said. "Congress' power to lay and collect taxes is more limited and less coercive than its power to regulate interstate commerce, which -- before this decision -- increasingly appeared to have no limit."


"The court's decision precludes Congress from venturing into new regulatory territory under the guise of regulating commerce," he said. "At the very least, it forecloses future governmental regulation that uses a person's inaction as a basis to compel them to act."


Lemper said the court's decision also broke new ground in restricting Congress' power under the Spending Clause. Seven of the justices -- "a majority of rare size for this court" -- held that the Affordable Care Act wrongly coerced states into accepting the Medicare expansion by threatening them with the loss of all Medicare funding (a significant portion of states' budgets) if they refused to do so.


"The court's decision is remarkable because it is the first time that the court has ever struck down a federal law under the Spending Clause on the ground that it runs counter to the system of federalism in the Constitution," he added. "For decades, the court has recognized the possibility that the federalism principles could limit Congress' power under the Spending Clause, but it had never actually done so until its decision on the Affordable Care Act.


"Its landmark holding gives real teeth to limits on Congress' power that had previously only existed in theory."



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Source: http://www.eurekalert.org/pub_releases/2013-10/iu-sco103113.php
Category: julianne hough   Alexian Lien   liam hemsworth   anthony weiner   Gia Allemand  

Suzaku study points to early cosmic 'seeding'

Suzaku study points to early cosmic 'seeding'


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Contact: Francis Reddy
francis.j.reddy@nasa.gov
301-286-4453
NASA/Goddard Space Flight Center






Most of the universe's heavy elements, including the iron central to life itself, formed early in cosmic history and spread throughout the universe, according to a new study of the Perseus Galaxy Cluster using Japan's Suzaku satellite.


Between 2009 and 2011, researchers from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), jointly run by Stanford University and the Department of Energy's SLAC National Accelerator Laboratory in California, used Suzaku's unique capabilities to map the distribution of iron throughout the Perseus Galaxy Cluster.


What they found is remarkable: Across the cluster, which spans more than 11 million light-years of space, the concentration of X-ray-emitting iron is essentially uniform in all directions.


"This tells us that the iron -- and by extension other heavy elements -- already was widely dispersed throughout the universe when the cluster began to form," said KIPAC astrophysicist Norbert Werner, the study's lead researcher. "We conclude that any explanation of how this happened demands lead roles for supernova explosions and active black holes."


The most profligate iron producers are type Ia supernovae, which occur either when white dwarf stars merge or otherwise acquire so much mass that they become unstable and explode. According to the Suzaku observations, the total amount of iron contained in the gas filling the cluster amounts to 50 billion times the mass of our sun, with about 60 percent of that found in the cluster's outer half.


The team estimates that at least 40 billion type Ia supernovae contributed to the chemical "seeding" of the space that later became the Perseus Galaxy Cluster.


Making the iron is one thing, while distributing it evenly throughout the region where the cluster formed is quite another. The researchers suggest that everything came together during one specific period of cosmic history.


Between about 10 and 12 billion years ago, the universe was forming stars as fast as it ever has. Abundant supernovae accompany periods of intense star formation, and the rapid-fire explosions drove galaxy-scale outflows. At the same time, supermassive black holes at the centers of galaxies were at their most active, rapidly accreting gas and releasing large amounts of energy, some of which drove powerful jets. Together, these galactic "winds" blew the chemical products of supernovae out of their host galaxies and into the wider cosmos.


Sometime later, in the regions of space with the largest matter densities, galaxy clusters formed, scooping up and mixing together the cosmic debris from regions millions of light-years across.


"If our scenario is correct, then essentially all galaxy clusters with masses similar to the Perseus Cluster should show similar iron concentrations and smooth distributions far from the center," said co-author Ondrej Urban, also at KIPAC.


Galaxy clusters contain hundreds to thousands of galaxies, as well as enormous quantities of diffuse gas and dark matter, bound together by their collective gravitational pull.


New gas entering the cluster falls toward its center, eventually moving fast enough to generate shock waves that heat the infalling gas. In the Perseus Cluster, gas temperatures reach as high as 180 million degrees Fahrenheit (100 million C), so hot that the atoms are almost completely stripped of their electrons and emit X-rays.


The Perseus Galaxy Cluster, which is located about 250 million light-years away and named for its host constellation, is the brightest extended X-ray source beyond our own galaxy, and the brightest and closest cluster for which Suzaku has attempted to map outlying gas.


The team used Suzaku's X-ray telescopes to make 84 observations of the Perseus Cluster, resulting in radial maps along eight different directions. Thanks to the sensitivity of the spacecraft's instruments, the researchers could measure the iron distribution of faint gas in the cluster's outermost reaches, where new gas continues to fall into it.


The findings will be published in the Oct. 31 issue of the journal Nature.


Suzaku (Japanese for "red bird of the south") was launched as Astro-E2 on July 10, 2005, and renamed in orbit. The observatory was developed by the Japan Aerospace Exploration Agency's Institute of Space and Astronautical Science in collaboration with NASA and other Japanese and U.S. institutions. NASA Goddard supplied Suzaku's X-ray telescopes and data-processing software and continues to operate a facility that supports U.S. astronomers who use the spacecraft.


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Suzaku study points to early cosmic 'seeding'


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PUBLIC RELEASE DATE:

31-Oct-2013



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Contact: Francis Reddy
francis.j.reddy@nasa.gov
301-286-4453
NASA/Goddard Space Flight Center






Most of the universe's heavy elements, including the iron central to life itself, formed early in cosmic history and spread throughout the universe, according to a new study of the Perseus Galaxy Cluster using Japan's Suzaku satellite.


Between 2009 and 2011, researchers from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), jointly run by Stanford University and the Department of Energy's SLAC National Accelerator Laboratory in California, used Suzaku's unique capabilities to map the distribution of iron throughout the Perseus Galaxy Cluster.


What they found is remarkable: Across the cluster, which spans more than 11 million light-years of space, the concentration of X-ray-emitting iron is essentially uniform in all directions.


"This tells us that the iron -- and by extension other heavy elements -- already was widely dispersed throughout the universe when the cluster began to form," said KIPAC astrophysicist Norbert Werner, the study's lead researcher. "We conclude that any explanation of how this happened demands lead roles for supernova explosions and active black holes."


The most profligate iron producers are type Ia supernovae, which occur either when white dwarf stars merge or otherwise acquire so much mass that they become unstable and explode. According to the Suzaku observations, the total amount of iron contained in the gas filling the cluster amounts to 50 billion times the mass of our sun, with about 60 percent of that found in the cluster's outer half.


The team estimates that at least 40 billion type Ia supernovae contributed to the chemical "seeding" of the space that later became the Perseus Galaxy Cluster.


Making the iron is one thing, while distributing it evenly throughout the region where the cluster formed is quite another. The researchers suggest that everything came together during one specific period of cosmic history.


Between about 10 and 12 billion years ago, the universe was forming stars as fast as it ever has. Abundant supernovae accompany periods of intense star formation, and the rapid-fire explosions drove galaxy-scale outflows. At the same time, supermassive black holes at the centers of galaxies were at their most active, rapidly accreting gas and releasing large amounts of energy, some of which drove powerful jets. Together, these galactic "winds" blew the chemical products of supernovae out of their host galaxies and into the wider cosmos.


Sometime later, in the regions of space with the largest matter densities, galaxy clusters formed, scooping up and mixing together the cosmic debris from regions millions of light-years across.


"If our scenario is correct, then essentially all galaxy clusters with masses similar to the Perseus Cluster should show similar iron concentrations and smooth distributions far from the center," said co-author Ondrej Urban, also at KIPAC.


Galaxy clusters contain hundreds to thousands of galaxies, as well as enormous quantities of diffuse gas and dark matter, bound together by their collective gravitational pull.


New gas entering the cluster falls toward its center, eventually moving fast enough to generate shock waves that heat the infalling gas. In the Perseus Cluster, gas temperatures reach as high as 180 million degrees Fahrenheit (100 million C), so hot that the atoms are almost completely stripped of their electrons and emit X-rays.


The Perseus Galaxy Cluster, which is located about 250 million light-years away and named for its host constellation, is the brightest extended X-ray source beyond our own galaxy, and the brightest and closest cluster for which Suzaku has attempted to map outlying gas.


The team used Suzaku's X-ray telescopes to make 84 observations of the Perseus Cluster, resulting in radial maps along eight different directions. Thanks to the sensitivity of the spacecraft's instruments, the researchers could measure the iron distribution of faint gas in the cluster's outermost reaches, where new gas continues to fall into it.


The findings will be published in the Oct. 31 issue of the journal Nature.


Suzaku (Japanese for "red bird of the south") was launched as Astro-E2 on July 10, 2005, and renamed in orbit. The observatory was developed by the Japan Aerospace Exploration Agency's Institute of Space and Astronautical Science in collaboration with NASA and other Japanese and U.S. institutions. NASA Goddard supplied Suzaku's X-ray telescopes and data-processing software and continues to operate a facility that supports U.S. astronomers who use the spacecraft.


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Source: http://www.eurekalert.org/pub_releases/2013-10/nsfc-ssp103113.php
Tags: Pumpkin Carving Ideas   penn state   NASA   anthony weiner   Lisa Robin Kelly  

Inside The Dungeon of Doom: Kevin Sullivan on wrestling's wackiest group










In summer 1995, one year before the emergence of The nWo, WCW was stuck in a seemingly inescapable limbo. The era of Ric Flair’s thrilling rivalries against Vader, Sting and Ricky Steamboat was in the rearview mirror. Hulk Hogan had arrived one year prior, but he wasn’t being accepted by Atlanta crowds with the same maniacal frenzy that had stirred up WWE fans in the ’80s.

The lead producer of WCW at the time, Kevin Sullivan – a Boston-bred veteran brawler – needed to come up with something. He needed to do it fast. And what he came up with might be the single most absurd narrative that has ever unfolded in one of the major sports-entertainment organizations — The Dungeon of Doom.

View photos of The Dungeon of Doom's members | Watch the absurd videos inside The Dungeon's lair

A cadre of cartoonish villains that assembled in a haunted fortress, The Dungeon grew and grew to amass no fewer than 20 individual members, each more ridiculous than the next. Watching the group’s television segments today is a surreal experience and plays like a B-movie out of the mind of Troma’s Lloyd Kauffman. There were bizarre sci-fi elements like teleportation, Hogan’s turn to “the dark side” long before going Hollywood and even the first on-screen appearance of Big Show.

With the rise of YouTube, the group's run has developed a cult following thanks to its cheap production values and endlessly quotable lines like, “It’s not hot!” Fascinated by the the macabre world of The Dungeon of Doom, and the notion that its existence overlapped with the intense realism of The nWo, WWEClassics.com set out to discover the inside story. We sat down with Kevin Sullivan, the Dungeon's Taskmaster, to find out what made the group tick and why it even happened at all.












Source: http://www.wwe.com/classics/kevin-sullivan-on-the-dungeon-of-doom
Category: Beyond Two Souls   lsu football   Vma Miley Cyrus   Chelsea Manning   Hyperloop  

Video: What's new in Android 4.4 design

For the more visually minded folks, Google's whipped up a video with Android's Nick Butcher, Adam Koch and Roman Nurik discussing some of the new design elements in Android 4.4 KitKat. Have at it!


    






Source: http://feedproxy.google.com/~r/androidcentral/~3/brjdWorUgV0/story01.htm
Category: day of the dead   USA vs Costa Rica   Rihanna   area 51   whitney houston  

Google's Search Results Can Deep-Link To Your Android Apps


It should be clear by now that there’s much more at play in Android 4.4 KitKat than some early reports alluded to, and one of the more interesting (to me, anyway) tidbits managed to escape the early leak treatment.


Tucked away toward the tail-end of Google’s Nexus 5/KitKat presentation was a mention of a feature called App Indexing that should get companies (and the Android app developers that work for them) a little worked up. That’s because Google has developed a way to deep-link to the contents of an app from within a user’s Google search results with a feature it calls App Indexing.


Here’s how it works. Say you’re using the Google Search app to dig up some dirt on that Ender’s Game movie that doesn’t look very good. If you happen to have the IMDb app installed on your device while you search, you’ll be treated to an info card in that results stream that includes an “Open in app” button. Give it a quick tap and the IMDb app will spring to life and immediately direct you to its Ender’s Game listing.


Naturally, the feature isn’t just limited to showing off movie details — so far the full list of supporters includes Allthecooks, AllTrails, Beautylish, Etsy, Expedia, Flixster, Healthtap, IMDb, Moviefone, Newegg (yes!), OpenTable, and Trulia.


The way Google sees it, the move is all about providing these companies with a choice. If they think their mobile interfaces are enough to keep users engaged, they can simple go about their business. But if they already have an Android app (or are in the process of building one) that can do a better job of engaging with its users, a little extra work to implement those deep links may be well worth it.


It’s not hard to look at this as a move to bolster Android app development, either. There’s little doubting that Android is a global force — which may be only compounded by the fact that Android 4.4 KitKat may drive device sales in developing markets by bringing a more advanced feature set to cheap hardware — and in many cases the Google Search app is going along for the ride. That means that with any luck, huge swaths of the global Android community will be searching for stuff using the Google search app and seeing those deep-linked “Open in app” buttons when they’ve got the right apps installed. Tell me that’s not a compelling reason for a company to develop an Android app if they haven’t already.


Despite the buy-in from all those app partners, it’ll be some time before users like me will actually start getting those results in the wild. Google is testing the feature with those previously listed partners, but the updated cards that will display that information won’t actually roll out until some time in November.



Source: http://feedproxy.google.com/~r/Techcrunch/~3/tPCTBkHPhm0/
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How the Nexus 5 Compares to Its Toughest Smartphone Competition

How the Nexus 5 Compares to Its Toughest Smartphone Competition

Finally, the long-awaited Nexus 5 has arrived in the form of 5 inches of pure, unfiltered Android just the way Google always intended. That all sounds nice, but as Google's flagship response to other big dogs like the iPhone 5S and Lumia 1020, does the refreshed Nexus have the specs to keep up with the competition (at least one paper)? We put together the comparison charts below to find out.

Read more...


    






Source: http://feeds.gawker.com/~r/gizmodo/full/~3/PQTkbYDuCZw/how-the-nexus-5-compares-to-its-toughest-smartphone-com-1456332159
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Breakthrough research produces brighter, more efficiently produced lighting

Breakthrough research produces brighter, more efficiently produced lighting


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PUBLIC RELEASE DATE:

30-Oct-2013



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Contact: Sonia Fernandez
sonia.fernandez@ia.ucsb.edu
805-893-4765
University of California - Santa Barbara






(Santa Barbara, Calif.) By determining simple guidelines, researchers at UC Santa Barbara's Solid State Lighting & Energy Center (SSLEC) have made it possible to optimize phosphors a key component in white LED lighting allowing for brighter, more efficient lights.


"These guidelines should permit the discovery of new and improved phosphors in a rational rather than trial-and-error manner," said Ram Seshadri, a professor in the university's Department of Materials as well as in its Department of Chemistry and Biochemistry, of the breakthrough contribution to solid-state lighting research. The results of this research, performed jointly with materials professor Steven DenBaars and postdoctoral associate researcher Jakoah Brgoch, appear in The Journal of Physical Chemistry.


LED (light-emitting diode) lighting has been a major topic of research due to the many benefits it offers over traditional incandescent or fluorescent lighting. LEDs use less energy, emit less heat, last longer and are less hazardous to the environment than traditional lighting. Already utilized in devices such as street lighting and televisions, LED technology is becoming more popular as it becomes more versatile and brighter.


According to Seshadri, all of the recent advances in solid-state lighting have come from devices based on gallium nitride LEDs, a technology that is largely credited to UCSB materials professor Shuji Nakamura, who invented the first high-brightness blue LED. In solid-state white lighting technology, phosphors are applied to the LED chip in such a way that the photons from the blue gallium nitride LED pass through the phosphor, which converts and mixes the blue light into the green-yellow-orange range of light. When combined evenly with the blue, the green-yellow-orange light yields white light.


The notion of multiple colors creating white may seem counterintuitive. With reflective pigments, mixing blue and yellow yields green; however, with emissive light, mixing such complementary colors yields white.



Art to science


Until recently, the preparation of phosphor materials was more an art than a science, based on finding crystal structures that act as hosts to activator ions, which convert the higher-energy blue light to lower-energy yellow/orange light.


"So far, there has been no complete understanding of what make some phosphors efficient and others not," Seshadri said. "In the wrong hosts, some of the photons are wasted as heat, and an important question is: How do we select the right hosts?"


As LEDs become brighter, for example a they are used in vehicle front lights, they also tend to get warmer, and, inevitably, this impacts phosphor properties adversely.


"Very few phosphor materials retain their efficiency at elevated temperatures," Brgoch said. "There is little understanding of how to choose the host structure for a given activator ion such that the phosphor is efficient, and such that the phosphor efficiency is retained at elevated temperatures."


However, using calculations based on density functional theory, which was developed by UCSB professor and 1998 Nobel Laureate Walter Kohn, the researchers have determined that the rigidity of the crystalline host structure is a key factor in the efficiency of phosphors: The better phosphors possess a highly rigid structure. Furthermore, indicators of structural rigidity can be computed using density functional theory, allowing materials to be screened before they are prepared and tested.


This breakthrough puts efforts for high-efficiency, high-brightness, solid-state lighting on a fast track. Lower-efficiency incandescent and fluorescent bulbs which use relatively more energy to produce light could become antiquated fixtures of the past.


"Our target is to get to 90 percent efficiency, or 300 lumens per watt," said DenBaars, who also is a professor of electrical and computer engineering and co-director of the SSLEC. Current incandescent light bulbs, by comparison, are at roughly 5 percent efficiency, and fluorescent lamps are a little more efficient at about 20 percent.


"We have already demonstrated up to 60 percent efficiency in lab demos," DenBaars said.


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Breakthrough research produces brighter, more efficiently produced lighting


[ Back to EurekAlert! ]

PUBLIC RELEASE DATE:

30-Oct-2013



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Contact: Sonia Fernandez
sonia.fernandez@ia.ucsb.edu
805-893-4765
University of California - Santa Barbara






(Santa Barbara, Calif.) By determining simple guidelines, researchers at UC Santa Barbara's Solid State Lighting & Energy Center (SSLEC) have made it possible to optimize phosphors a key component in white LED lighting allowing for brighter, more efficient lights.


"These guidelines should permit the discovery of new and improved phosphors in a rational rather than trial-and-error manner," said Ram Seshadri, a professor in the university's Department of Materials as well as in its Department of Chemistry and Biochemistry, of the breakthrough contribution to solid-state lighting research. The results of this research, performed jointly with materials professor Steven DenBaars and postdoctoral associate researcher Jakoah Brgoch, appear in The Journal of Physical Chemistry.


LED (light-emitting diode) lighting has been a major topic of research due to the many benefits it offers over traditional incandescent or fluorescent lighting. LEDs use less energy, emit less heat, last longer and are less hazardous to the environment than traditional lighting. Already utilized in devices such as street lighting and televisions, LED technology is becoming more popular as it becomes more versatile and brighter.


According to Seshadri, all of the recent advances in solid-state lighting have come from devices based on gallium nitride LEDs, a technology that is largely credited to UCSB materials professor Shuji Nakamura, who invented the first high-brightness blue LED. In solid-state white lighting technology, phosphors are applied to the LED chip in such a way that the photons from the blue gallium nitride LED pass through the phosphor, which converts and mixes the blue light into the green-yellow-orange range of light. When combined evenly with the blue, the green-yellow-orange light yields white light.


The notion of multiple colors creating white may seem counterintuitive. With reflective pigments, mixing blue and yellow yields green; however, with emissive light, mixing such complementary colors yields white.



Art to science


Until recently, the preparation of phosphor materials was more an art than a science, based on finding crystal structures that act as hosts to activator ions, which convert the higher-energy blue light to lower-energy yellow/orange light.


"So far, there has been no complete understanding of what make some phosphors efficient and others not," Seshadri said. "In the wrong hosts, some of the photons are wasted as heat, and an important question is: How do we select the right hosts?"


As LEDs become brighter, for example a they are used in vehicle front lights, they also tend to get warmer, and, inevitably, this impacts phosphor properties adversely.


"Very few phosphor materials retain their efficiency at elevated temperatures," Brgoch said. "There is little understanding of how to choose the host structure for a given activator ion such that the phosphor is efficient, and such that the phosphor efficiency is retained at elevated temperatures."


However, using calculations based on density functional theory, which was developed by UCSB professor and 1998 Nobel Laureate Walter Kohn, the researchers have determined that the rigidity of the crystalline host structure is a key factor in the efficiency of phosphors: The better phosphors possess a highly rigid structure. Furthermore, indicators of structural rigidity can be computed using density functional theory, allowing materials to be screened before they are prepared and tested.


This breakthrough puts efforts for high-efficiency, high-brightness, solid-state lighting on a fast track. Lower-efficiency incandescent and fluorescent bulbs which use relatively more energy to produce light could become antiquated fixtures of the past.


"Our target is to get to 90 percent efficiency, or 300 lumens per watt," said DenBaars, who also is a professor of electrical and computer engineering and co-director of the SSLEC. Current incandescent light bulbs, by comparison, are at roughly 5 percent efficiency, and fluorescent lamps are a little more efficient at about 20 percent.


"We have already demonstrated up to 60 percent efficiency in lab demos," DenBaars said.


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Source: http://www.eurekalert.org/pub_releases/2013-10/uoc--brp103013.php
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