Sunday, December 28, 2008
It was long after Avogadro that the idea of a mole was introduced. Since a molecular weight in grams (mole) of any substance contains the same number of molecules, then according to Avogadro's Principle, the molar volumes of all gases should be the same. The number of molecules in one mole is now called Avogadro's number. It must be emphasised that Avogadro, of course, had no knowledge of moles, or of the number that was to bear his name. Thus the number was never actually determined by Avogadro himself.
As we all know today, Avogadro's number is very large, the presently accepted value being 6.0221367 x 1023. The size of such a number is extremely difficult to comprehend. There are many awe-inspiring illustrations to help visualize the enormous size of this number. For example:
- An Avogadro's number of standard soft drink cans would cover the surface of the earth to a depth of over 200 miles.
- If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.
- If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.
Determination of the number
Cannizarro, around 1860, used Avogadro's ideas to obtain a set of atomic weights, based upon oxygen having an atomic weight of 16. In 1865, Loschmidt used a combination of liquid density, gaseous viscosity, and the kinetic theory of gases, to establish roughly the size of molecules, and hence the number of molecules in 1 cm3 of gas.
During the latter part of the nineteenth century, it was possible to obtain reasonable estimates for Avogadro's number from sedimentation measurements of colloidal particles. Into the twentieth century, then Mullikan's oil drop experiment gave much better values, and was used for many years.
A more modern method is to calculate the Avogadro number from the density of a crystal, the relative atomic mass, and the unit cell length, determined from x-ray methods. To be useful for this purpose, the crystal must be free of defects. Very accurate values of these quantities for silicon have been measured at the National Institute for Standards and Technology (NIST).
To use this approach, it is necessary to have accurate values of atomic weights, often obtained by measuring the mass of atomic ions. For example, an ion trap, employing extremely uniform and stable magnetic and electric fields should allow such measurements to be made to better than 1 part in 1010. The relative atomic mass of silicon is particularly important, since silicon crystals are used in the x-ray methods mentioned above.
As a continuation of this approach, one of the 1999 NIST Precision Measurement Grants was awarded to David Pritchard, physics professor at the Massachusetts Institute of Technology. He will conduct cyclotron frequency measurements on ions that could achieve a 100-fold improvement in the accuracy of atomic mass measurements. MIT has developed the world's most accurate mass spectrometer capable of measuring the atomic mass of atoms to one part in 10 billion. Pritchard proposes to simultaneously measure the cyclotron frequencies of two different ions in order to improve the values of several fundamental constants, including Avogadro's number.
At the present time, information on Avogadro's number from many different experiments is pooled with other observations on other physical constants. A most probable and self-consistent set of physical constants that best fits all reliable data is then found by statistical methods.
The size of Avogadro's number is determined by our definition of the mole. What it does demonstrate is how small an atom or molecule is compared to the amounts of material we are familiar with in everyday life, since the definition of the mole involves amounts of material we are completely familiar with.
Wednesday, December 10, 2008
- Gears is not fully implemented, just try Google Docs offlineBad, bad, bad! They created a kickass browser and then stranded its users with no add-ons.
- There are no toolbars or useful plugins
- A crashed process in one tab is not supposed to crash the browser, but it will
- Google continues to create plug-ins and toolbars for FireFox and IE but not for Chrome.
Monday, December 1, 2008
Triple Helix: Designing a New Molecule of Life: Scientific American
Triple Helix: Designing a New Molecule of Life
Friday, November 28, 2008
"Several benchmarks show Lua as the fastest language in the realm of interpreted scripting languages. Lua is fast not only in fine-tuned benchmark programs, but in real life too. A substantial fraction of large applications have been written in Lua."
Roberto IerusalimschyAssociate Professor, Departamento de Informática, PUC-Rio
Departamento de Informática, PUC-Rio
Rua M. S. Vicente 225
22451-900 Rio de Janeiro, Brazil
+(55)(21)3527-1506, ext. 4343
Wednesday, November 26, 2008
On the list:
- Cloud computing
- Servers – beyond blades
- Web-oriented architectures
- Enterprise mashups
- Specialized systems
- Social software and social networking
- Unified communications
- Business intelligence
- Green IT
Thursday, November 20, 2008
Saturday, November 15, 2008
Thursday, November 6, 2008
Wednesday, November 5, 2008
Scobleizer - Tech geek blogger - Blog Archive Never underestimate Microsoft;s ability to turn a corner.
1. On day 1 of the PDC they announced Azure, which is a set of cloud services that competes with Amazon’s S3 and Rackspace’s Mosso and will radically change enterprises’ acceptance of cloud services for a whole lot of reasons.
2. On day 2 of the PDC they showed off Windows 7 which is getting high praise from my blogging friends who were lent laptops with it on there (I didn’t get Windows 7 yet).
3. On day 3 of the PDC they showed off new Web-based versions of Microsoft Office that were really nice. Will the new PowerPoint have the collaborative features, of, say, SlideRocket? Will Zoho go out of business? No, and no, but this is a significant move into the Web for a group that’s tried to pretend that the Web didn’t matter that much.
4. They also released new Mac and Mobile versions of Mesh and further explained how that’ll enable new kinds of Internet-connected apps to be built.
Some really great resources on all this:
Microsoft put up videos of every session at the PDC.
Ars Technica covered it well.
Microsoft’s own Channel 9 has a ton of videos.
Monday, November 3, 2008
Saturday, November 1, 2008
Thursday, October 30, 2008
About Microsoft ClearType
Microsoft ClearType is an unprecedented innovation in font display technology that dramatically improves font display resolution and marks a genuine breakthrough in screen readability.
Internet Explorer 8 Beta 1 Users
Installing IE8 Beta1 on Windows XP SP3 is fully supported, so go ahead and upgrade your computers to XPSP3 and then install IE8 Beta 1 to try out our new features. You will be able to uninstall IE8 Beta 1 at any point to revert back to either IE7 or IE6 depending on what you were using before.
However, if you already have IE8 Beta 1 installed on XPSP2, Windows XP SP3 will not be offered to you via Windows Update. This is because after you update your system to XPSP3, you will no longer be able to uninstall IE8 Beta 1 and the Remove option will be grayed out under the Add/Remove programs in Control Panel. The reason is the same as in IE7 case described above. Since people are more likely to uninstall beta software, we strongly recommend uninstalling IE8 Beta 1 prior to upgrading to Windows XP SP3 to eliminate any deployment issues and install IE8 Beta 1 after XPSP3 is on your machine.
Tuesday, October 28, 2008
Wednesday, October 22, 2008
- Right-click on the application file and choose "Properties" (if you right-click on a shortcut, choose "Find Target" to get to the application file, then go to step 1)
- Choose the "Compatibility" tab
- Click the checkbox "Turn off advanced text services for this program."
Thursday, September 18, 2008
Torvalds pans Apple with 'utter crap' putdown - Technology - smh.com.au:
"Torvalds was in Melbourne last week for the linux.conf.au conference and was invited to pass judgement on OS X versus Windows Vista in a wide-ranging interview.
'I don't think they're equally flawed - I think Leopard is a much better system,' he said. '(But) OS X in some ways is actually worse than Windows to program for. Their file system is complete and utter crap, which is scary.'"
Sunday, September 14, 2008
Benefits of XForms include:
- Clear separation between data captured and presentation (separation of concerns)
- Flexible, structured XML-based data model: define your data model as an XML document, then create forms accessing the data
- Built-in facilities for validation and data integrity based on XML Schema and/or assertions
- Declarative approach requiring less / no scripting at all, in particular thanks to declarative events and actions
- Ease of internationalization
- Support for a variety of devices
- W3C standard
- Not tied to a particular platform or language such as Java or .NET
The W3C on XForms.
Saturday, September 13, 2008
Saturday, September 6, 2008
Friday, September 5, 2008
What it is you have to experience to understand.
KallOut(TM) opens video, content, definitions, searches - everything - in dialog balloons, just like you have imagined the Web could be.
At this rate, we will have flying cars in no time.
Thursday, September 4, 2008
Tuesday, August 26, 2008
Wednesday, August 20, 2008
Another reason for using Ruby is that it really is fun. One of the goals that Yukihiro 'Matz' Matsumoto, Ruby's creator, gave for creating the language is to make programming easy and fun. Once you begin to use Ruby, you seem to recapture some of the joy and wonder that you had when you started your programming.
Tuesday, August 19, 2008
Agile home ground:
Requirements change very often
Small number of developers
Culture that thrives on chaos
Plan-driven home ground:
Requirements don't change too often
Large number of developers
Culture that demands order
Isolation, and Durability.
Atomicity means that operations with the database can be grouped
together and treated as a single unit.
Consistency guarantees that either all the operations in this single
unit (or transaction) are performed successfully, or none of them is
performed. In other words, a database can't be in an unfinished state.
To understand why these characteristics are important, think about a
bank transaction during which money is transferred from a savings
account into a checking account. If the transfer process fails after
subtracting the money from your savings account and before it was
added to your checking account, you would become poorer, and the bank
would have an angry (ex)customer! Atomicity enables the two operations
-- the subtraction from the savings account and the addition to the
checking account -- to be treated as a single transaction. Consistency
guarantees that both operations in the transaction either succeed or
fail. That way, your money isn't lost.
Isolation means that independent sets of database transactions are
performed in such a way that they don't conflict with each other.
Continuing the bank analogy, consider two customers who transfer funds
between accounts at the same time. The database must track both
transfers separately; otherwise, the funds could go into the wrong
accounts, and the bank might be left with two angry (ex)customers.
Durability guarantees that the database is safe against unexpected
terminations. It may be a minor inconvenience if your television or
computer won't work when the power goes out, but the same can't be
said for a database. If the bank's computers lose power when
transferring your funds, you won't be a happy customer if the
transaction is lost. Durability guarantees that if the database
terminates abnormally during a funds transfer, then when the database
is brought back up, it will be able to recover the transaction and
continue with normal operations.
Sunday, August 17, 2008
Saturday, August 16, 2008
The device driver for your network card is preventing PC from entering standby or hibernation - BeyondTeck
This page gives a super simple solution to this problem.
Tuesday, August 12, 2008
Nasa hopes its Orion ship will take it back to the Moon.
Nasa has pushed back by a year its internal target date for flying the successor to the shuttle.
Agency officials say they are now aiming for September 2014 for the first crewed mission of the Orion ship.
This is a year later than Nasa had hoped for, but still inside its March 2015 absolute deadline."
Friday, August 8, 2008
Monday, August 4, 2008
Thanks to Google App Engine, you don't have to worry about any of that. App Engine's infrastructure takes care of all of the distribution, replication and load balancing of data behind a simple API—and you get a powerful query engine and transactions as well."
Wednesday, July 23, 2008
Tuesday, July 8, 2008
1. Data: symbols
2. Information: data that are processed to be useful; provides answers to 'who', 'what', 'where', and 'when' questions
3. Knowledge: application of data and information; answers 'how' questions
4. Understanding: appreciation of 'why'
5. Wisdom: evaluated understanding."
Monday, June 9, 2008
CWDM - Coarse Wave Division Multiplexed
DCE - Dynamic Channel Equalizer
DWDM - Dense Wavelength Division Multiplexed
MEMS - Micro Electro Mechanical Systems
OADM - Optical Add Drop Multiplexer
ROADM - Reconfigurable Optical Add Drop Multiplexer
WSS - Wavelength Selective Switch
Thursday, June 5, 2008
- Ludwig Wittgenstein
You can only be young once. But you can always be immature.
- Dave Barry
Talent hits a target no one else can hit; Genius hits a target no one else can see.
- Arthur Schopenhauer
Thursday, May 22, 2008
Saturday, May 10, 2008
1. Insert a blank disc.
2. Start Disk Utility.
3. From the File menu, choose Open Disk Image and select the ISO to be burned.
4. In the list of volumes, you will now see an item representing the ISO file. Select it.
5. Click the Burn button and follow the instructions."
Thursday, May 8, 2008
Add support for the scroll wheel to the Microsoft Visual Basic for Applications 6 environment - Help and How-to - Microsoft Office Online
Wednesday, March 5, 2008
Twinkling in the sky is a diamond star of 10 billion trillion trillion carats, astronomers have discovered.
Tuesday, February 26, 2008
by James Baughn
SILICON VALLEY, CALIFORNIA (SVC) -- According to a recent study by the Blartner Group, 99.5% of all possible five letter combinations have already been appropriated for computer industry acronyms. The impending shortage of 5LC's is casting a dark shadow over the industry, which relies heavily on short, easy-to-remember acronyms for everything from product names to inside jokes.
"Acronym namespace collisions (ANCs) are increasing at a fantastic rate and threaten the very fabric of the computing world," explained one ZD pundit. "For example, when somebody talks about XP, I don't know whether they mean eXtreme Programming or Microsoft's eXceptionally Pathetic operating system. We need to find a solution to this problem fast or chaos could be the result."
Leaders of several SVC companies have floated the idea of an "industry-wide acronym conservation protocol" (IWACP -- one of the few 5LCs not already appropriated). Explained Bob Smith, CTO of IBM, "If companies would voluntarily limit the creation of new acronyms while recycling outdated names, we could reduce much of the pollution within the acronym namespace without the use of new government regulations or programs. The last thing we want is for Congress to get involved and try to impose a solution for this SAS (Severe Acronym Shortage -- also a software program) that would likely only create dozens of new acronyms in the process."
Several members of the Internet Engineering Task Force want to place a limit on the number of new acronyms that can be defined per RFC document. "We all know that a huge percentage of the industry's acronyms were given birth in old RFCs," said one IETF participant. "Every Internet protocol has two or three dozen acronyms attached to it. If we could get developers to refrain from acronymizing everything, we could nip the impending 'acronymclysm' in the bud."
Eric S. Raymond has offered to help by requesting that the Internet community refer to him simply as Eric S. Raymond instead of ESR, thus freeing up a coveted 3LC. (RMS, JWZ, and LBT were unavailable for comment at press time.) Mr. Raymond also wants open-source software developers to reconsider using the GPL or BSD licenses instead of inventing another license and creating yet another acronym in the process. "Open Source already depends heavily on a steady supply of acronyms -- 45.7% of projects on Freshmeat use acronyms for their names," he said. "Don't poison the water with acronyms for frivolous licenses -- let's use our precious natural resources wisely."
ICANN Emperor Luart Synn, desperately searching for a reason for his organization to exist, has offered to open up a new Top Level Domain exclusively for registering acronyms. "Within three months, every 5LC from AAAAA (American Association Against Acronym Abuse) to ZZZZZ (Zoe Zephyr's Zero Zucchini Zone [a store that sells only meat products]) will be occupied. What we need is a central registrar for domain names and a way to resolve disputes between competing parties that have claims to the same letter combinations. We can do for acronyms what we did for domain names."
Mr. Synn's proposal has drawn mostly yawns from the CIAL (Computer Industry At Large). It seems clear that BECs (Big Evil Companies) will always win out against SFTDHARPPs (Small Fish That Don't Have Any Real Political Power) in any acronym dispute. At any rate, most developers don't like the idea of submitting an ARR (Acronym Registration Requests) anytime they string a few capital letters together.
Indeed, some people believe that the "acronym shortage" is a myth. "The military and all other government bureaucracies have depleted the acronymspace for years," explained one member of the Humorix Vast Spy Network(tm). "Virtually every 3, 4, 5, and 6 letter acronym has been gobbled up by the US Air Force alone since at least the Reagan administration. Has there been a crisis? Has the government collapsed because people couldn't tell whether a PDO was a Paid Day Off or a Portable Distributed Object or a Pretty Dumb Officer? No! Life will go on no matter how many acronyms we define."
Friday, February 22, 2008
Wednesday, February 20, 2008
Friday, February 15, 2008
US scientists are taking the first step towards testing potentially hazardous chemicals on cells grown in a laboratory, without using live animals.
Thursday, February 14, 2008
Three U.S. agencies aim to end animal testing
An ambitious program announced today by a coalition of government agencies could lead to the end of animal testing to evaluate the safety of new chemicals and drugs.
By Elizabeth Weise, USA TODAY
Sunday, February 10, 2008
VeriSign also has a long partnership with OpenID, said Nico Popp, the company's vice president of innovation. Popp told InternetNews.com that in the future, a top priority will be to ensure that the standards and protocol of OpenID remain open.
Tuesday, February 5, 2008
Friday, February 1, 2008
¶6 of Steve Balmer's letter to the Yahoo! Board:
"While online advertising growth continues, there are significant benefits of scale in
advertising platform economics, in capital costs for search index build-out, and in research
and development, making this a time of industry consolidation and convergence. Today, the
market is increasingly dominated by one player who is consolidating its dominance through
acquisition. Together, Microsoft and Yahoo! can offer a credible alternative for consumers,
advertisers, and publishers. Synergies of this combination fall into four areas:
Scale economics: This combination enables synergies related to scale economics of the
advertising platform where today there is only one competitor at scale. This includes
synergies across both search and non-search related advertising that will strengthen the
value proposition to both advertisers and publishers. Additionally, the combination allows
us to consolidate capital spending.
Expanded R&D capacity: The combined talent of our engineering resources can be focused on
R&D priorities such as a single search index and single advertising platform. Together we
can unleash new levels of innovation, delivering enhanced user experiences, breakthroughs in
search, and new advertising platform capabilities. Many of these breakthroughs are a
function of an engineering scale that today neither of our companies has on its own.
Operational efficiencies: Eliminating redundant infrastructure and duplicative operating
costs will improve the financial performance of the combined entity.
Emerging user experiences: Our combined ability to focus engineering resources that drive
innovation in emerging scenarios such as video, mobile services, online commerce, social
media, and social platforms is greatly enhanced."
Thursday, January 31, 2008
Creating multiple Google Chrome profiles is fairly easy on a PC, there's even a program for doing all the legwork for you . Not so...
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