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Archive for May, 2011

ஒரு சந்தேகம்!

May 23rd, 2011 No comments

சிறையிலிட்ட சிலைகளிடம்
சில்லரையிட்டு;
சிக்கல்களுக்கு
சீக்கிரமாகவும், சிக்கனமாகவும், சிரமமில்லாமலும்
சிந்தையாலேயே சரிகட்ட
சிரம் தாழ்த்தி
சங்கல்பம்கொள்ளும் சிறியோர்க்கு
சிவனே சித்தமேற்றாலும்
சீக்கருக்கத்தான் முடியுமோ!

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Ramanashramam going Green

May 20th, 2011 No comments

Ramanashramam is probably the first bigger house that I know of and that’s open for public going GREEN on electricity usage.  The ashram management has enforced usage of LED fixtures as a replacement for incandescent bulbs and CFLs.  They have meticulously changed the focus lamps, 4″ tubes, roof lamps, flood lights, etc to power LED based fixtures despite their initial costs.  A most welcomed gesture to save the planet!

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Symmetric Sigmoid

May 14th, 2011 No comments
When unknown signed intervals are expected to be normalized to -1 to +1, a symmetric sigmoid function could prove very useful.  A Symmetric Sigmoid function is a modified version of the Sigmoid function by stretching it across the Y axis.  As per wikipedia, it is defined as a symmetric function is a special case of logistic function whose plot appears like a ‘S’ with the Y-axis intercept as 0.5 and min/max as 0/1 respectively.

The function definition for a sigmoid is:

In programming languages the implementation should be in order to overcome the numerical overflow and underflow issues:

if ( t < 0 )
    exp( t ) / ( 1.0 + ::exp( t ) )
else
    1.0 / ( 1.0 + ::exp( -t ) )

 

 

 

 

 

 

 

 

 

 

 

 

In the plot, if the curve is stretched in Y-axis to make the Y-intercept at 0.0, the lower bound would get stretched to -1.0.
The function definition for a symmetric sigmoid is:
P symmetric (t) = 2.0 * P(t) – 1.0

The function can also be defined in terms of hyperbolic tangent as:
P symmetric (t) = tanh(t)

With sigmoid functions, it becomes possible to normalize any range in [-∞, +∞] onto [-1.0, +1.0].

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Pizza Hut, Taylor’s Road

May 13th, 2011 3 comments

This is the scenario at Taylor’s Road, Kilpauk where Pizza Hut using Taylor’s Road as it’s private and permanent parking lot.  Although that is the lane allowed for parking by the Traffic police, it is not justified to occupy the public place for private parking!  This what the North Indians say as “Yeh desh mey sab chalega!”.

Another interesting observation that could be made is that, a bicycle is being used for delivering pizzas.  Taylor’s road Pizza hut uses Bajaj Platina as it’s preferred delivery vehicle.  But, today while having tea at the corner shop, I notice a bicycle parked (see the picture) which had the pizza cabinet fitted in the carrier.  I think, to combat hiking petrol prices, Pizza hut has decided to use bicycle for short distance deliveries, a very well welcomed idea, a green implementation too!
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Oil Cooler Assembly for Royal Enfield Thunderbird 350 AVL

May 9th, 2011 12 comments
The performance of a IC engine is directly dependent on the difference between the ambient temperature and the exhaust temperature.  If you had learned about IC engines, it is apparent that the power generated is proportional to the temperature difference between the inlet and the outlet feed for the engine.  So, it is critical to operate the engine under low temperature such that maximum power is generated by the engine.  To keep the engine cool, engine oil is used, which also serves as the lubricant for the moving parts.  Engine oil is the blood for an engine and it’s circulation is crucial for maintaining the temperature and low frictional loses.  There is no oil cooler assembly for TB, or for that matter any RE bikes in India. 

Chinmay Dhangre from Pune generously offered to supply a modified oil cooler.  I was excited to read a blog post by Chinmay at http://www.indiancarsbikes.in/automotive-technology/royal-enfield-avl-engine-oil-cooler-update-real-world-data-4175/. When I contacted Chinmay at macasp@gmail.com, he was readily helping me to get the necessary fitments and hardware.

The reason for keep the inlet at a higher position than the outlet is to ensure that some oil is pre-stored in the oil cooler compartment all the time.  When the engine is started, it takes >10 seconds for the oil to reach the rocker, tappet assembly through the Y pipe.  If I had put the oil cooler in the middle, it would take more time to fill the oil cooler and then reach the rocker assembly.  Having this inverted connection helps the oil start its circulation faster.

The oil cooler assembly and the Y pipes are connect via a nylon coated reinforced rubber tube.  While fitting so, care should be taken for keep the pipes away from the silencer tube.  Also, it is to be ensured the the joints don’t leak after they are secured by clamps.  In the above picture, one clamp is missing!

I had used one clamp to offset the nylon pipe from the silencer tube.  I will have to use some other method for this offseting, as I am indeed wasting a good clamp!

While draining the oil during oil replacement, one has to take care of removing the oil in the oil-cooler compartment by opening the bottom vent.  Otherwise, sludge can start to accumulate inside the oil cooler assembly, which could eventually block the oil flow later.  So, it should be practice that the oil cooler assembly is cleaned every time the engine is serviced.

The completed bike is able to keep the engine oil temperature lower by allowing the natural air flow cooling off the oil through the oil-cooler fins.  Do mind that while the bike is stationery, the oil cooler cannot provide any help as it needs air flow for cooling.
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Windows Server 2008 R2 Itatic font problem

May 5th, 2011 1 comment
    While doing some automatic windows updates, the default font for Windows 2008 R2 Server changed to Italics.  After getting perplexed about this problem and few hours of Internet searching, the solution was found at http://www.techsupportforum.com/forums/f217/problem-with-italic-fonts-everywhere-arial-233328.html.  Basically, it recommended a registry fix (see below), which seemed working perfectly. The replacement font prescribed in the registry fix sounded weird to me, so checked the name in http://en.wikipedia.org/wiki/Segoe and found that it belongs to the Sans-serif font category.
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\FontSubstitutes]
"MS Shell Dlg 2"="Segoe UI"
"MS Shell Dlg"="Segoe UI"
"Helv"="Segoe UI"
"MS Sans Serif 8,10,12,14,18,24"="Segoe UI"
"MS Serif 8,10,12,14,18,24"="Segoe UI"
"MS Sans Serif"="Segoe UI"
"System"="Segoe UI"
"Microsoft Sans Serif"="Segoe UI"
"Tahoma"="Segoe UI"
"MS Serif"="Segoe UI"
"Times New Roman"="Segoe UI"
"Times"="Segoe UI"
"Small Fonts"="Segoe UI"
"Tms Rmn"="Segoe UI"
"Arial"="Segoe UI"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts]
"Arial (TrueType)"="segoeui.ttf"
"Arial Italic (TrueType)"="segoeuii.ttf"
"Arial Bold (TrueType)"="segoeuib.ttf"
"Arial Bold Italic (TrueType)"="segoeuiz.ttf"
"Times New Roman (TrueType)"="segoeui.ttf"
"Times New Roman Italic (TrueType)"="segoeuii.ttf"
"Times New Roman Bold (TrueType)"="segoeuib.ttf"
"Times New Roman Bold Italic (TrueType)"="segoeuiz.ttf"
"Tahoma (TrueType)"="segoeui.ttf"
"Tahoma Bold (TrueType)"="segoeuib.ttf"
"Microsoft Sans Serif (TrueType)"="segoeui.ttf"
"MS Sans Serif 8,10,12,14,18,24 (VGA res)"="segoeui.ttf"
"MS Serif 8,10,12,14,18,24 (VGA res)"="segoeui.ttf"

[HKEY_CLASSES_ROOT\Local Settings\Software\Microsoft\Windows\Shell\MuiCache]
"@themeui.dll,-2037"="{Segoe UI, 8 pt}"
"@themeui.dll,-2038"="{Segoe UI, 8 pt}"
"@themeui.dll,-2039"="{Segoe UI, 8 pt}"
"@themeui.dll,-2040"="{Segoe UI, 8 pt}"
"@themeui.dll,-2041"="{Segoe UI, 8 pt}"
"@themeui.dll,-2042"="{Segoe UI, 8 pt}"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\FontMapper\FamilyDefaults]
"Swiss"="Segoe UI"
"Roman"="Segoe UI"

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ஆமை புகுந்த வீடும், “ஆமை”ரிக்கா புகுந்த நாடும் உருப்படுமா?

May 4th, 2011 No comments

ஆமை புகுந்த வீடு தேராது என்பது பழமொழி. ஆனால் ஆமை என்பது நீரிலும் நிலத்திலும் வாழும் ஆமையை குறிக்காது. அது கல்லாமை, பொல்லாமை, இல்லாமை, போன்ற {\b.*ஆமை}களை குறிக்கின்றன!

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யுவன் சங்கர் ராஜாவின் யுக்தி

May 4th, 2011 No comments
வித்தியாசமான ஒலிகளை எழுப்பும் கருவிகளை தத்தம் இசையமைத்த பாடல்களில் உபயோகிப்பதில் யுவன் மிகவும் கைதேர்ந்திருக்கிறார். எப்போது கேட்ட ஒலிகளை தாண்டி, தனித்த ஒலிகளை கேட்கும்போது வரும் கிறக்கமே தனிதான்.  ஹாரீஸ் ஜெயராஜ் கூட இதே யுக்தியை பயன்படுத்துகிறார்.

ஆண்டு படம் பாடல் இசை
2011 மங்காத்தா விளையாடு மங்காத்தா.. யுவன்
2011 பேசு வெண்ணிற இரவுகள், I have a dream.. யுவன்
2011 கோ அக நக ஹாரீஸ்
2010 நான் மகான் அல்ல கண்ணோரம் காதல் வந்தால்.. யுவன்
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HT12E & HT12D Rosc values

May 1st, 2011 1 comment

Choosing a appropriate value of ROSC is critical for the functioning of HT12E and HT12D pair during Muxing and DeMuxing.  The following are the value pairs that are found to be working correctly at 5V power supply for both the ICs.  Although, they support variety of voltages, it is always better to keep them at the same voltage to avoid confusion on the internal oscillator frequency.  If the data sheet is seen, it becomes apparent that the internal oscillator frequency is function of (Vdd, Rosc).

HT12E ROSC HT12D ROSC
1M 47K
1.1M 51K
750K 33K
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Modern wet grinder

May 1st, 2011 No comments

image

When I went to Kanchipuram to visit Ekambareswarar, I came across this shop where I’d stopped by to have some tea.  Though the tea tasted like neemcake soaked in hot water, I was intrigued to find that the gentleman in picture was preparing rice batter in a machine, that is typically used for dry grinding.  During my schooling days, I had been to flour mills several times to grind rice, wheat, chilly powder, etc.  There I used to observe how those grinding machines indeed work to grind the items quickly.

Not withstanding my curiousity, I went and asked the gentleman about the machine that he was using to make rice batter.  He said, such machines are available in use for quite some time, about 8 years.  But I have never seen this type of wet grinder before.  He said, these machines are quick and can produce batter that is very fine, unlike the traditional stone type wet grinders.  With him permission, I clicked this photo.

For the uneducated people, here is how the dry grinder work.  The machine’s main component is a pair of gear like perforated steel plates, where one is rotated by a heavy 3 phase motor and the other is stationary.  The plates operate very much like a clutch plate in an automobile.  The distance between the plates is controlled by a wheel.  Upon rotating it clockwise, the stationary plate gets closer to the rotating plate and vice versa.  The material to be ground, is feed through these plates where they are broken into smaller pieces.  Upon 2-3 iteration of grinding, the material can be ground to whatever finer requirement is by keeping the plates closer to each other.

Although, the above wet grinder is quick and capable of finer batter, I am wondering how it should be cleaner.  The process to be messy unlike the easy cleaning process of the stoned wet grinder.  May be, that’s the reason for the unpopularity of this wonderful machinery!

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