hi,

this is a much awaited reply of the post longwaited replies by ZERO.

I appreciate your endevour in digging out information and viewing the whole thing scientifically.

Your calculations are well performed and what i understand as a jist of it ,that human power can be limited upto 500 watts,but a vaccum cleaner may require upto 2200 watts,right?

But what i fail to understand is that how vaccum cleaner may run on just 150 watts?

I checked Eureka forbes website(http://www.eurekaforbes.com/products/product.php?catid=34&&prid=22)
and(http://www.eurekaforbes.com/products/product.php?catid=34&&prid=21)

and found this data:

For some product of theirs:

Rated Voltage 230 V AC, 50 Hz
Rated Current 0.65 amps
Rated Power 150 watts
Maximum Suction 4116 Pascals
(420 mm water column)
Dimension (l*d*h) 480 * 100 * 100 mm
Net Weight (main unit) 1.10 kg
Std. Accessories 4

And yet for another product,what you said was true:

Voltage 230 V AC, 50 HZ
Input power 2100 Watts
Suction 1600 mm/H20 or 15680 Pascals
Dimension (L * B * H) 400 * 355 * 500 mm
Net Weight 14.2 Kg

It boggles me how the first one runs on 150 watts power.
So,i think it might just not be impossible to build a mechanical vaccum cleaner.

What say?
Hugs for a great new year,
sameer



 

Longawaited replies

This is to reply to two posts I found close to my heart.
Going by chronological order.

1. Mechanical vacuums.

This reply will be a bit technical but do excuse me.
Bernoulli's principle as far as I understand is a clever restatement of the law of coservation of energy. Hence I will proceed with conservation of energy itself to check the feasibility of a mechanical vacuum.

Let us consider that the vacuum has a circular cross section nozzle with a radius of 1 cm.
A standard vacuum generates 20kPa pressure difference between outside and inside.
By Bernoulli's principle,
(1/2)*d*v^2 = (P2-P1)
Thus, v = 180 m/sec
Now, Power = (energy)/time = ((1/2)*m*v^2)/t = (1/2) *d*A*v^3
= (1/2)*(pi*(o.o1^2))*1.2*180^3 = 1100 watts
Assuming a modest efficiency for the mechanics at 50%.
Total input power = 2200 watts.
Power output of a human being working hard physically = 500 watts.
Hence I would tend to believe this is not feasible.

NOTES :
d= 1.2 kg/ m^3......density of dry air.
Standard data such as pressure diff. in vacuums and output of a human courtesy Wikipedia.

2. Mission to the moon

Construction of moon bases is not as easy as it seems.
NASA's press release though impressive, I believe is over optimistic.
The ISS which is one thirtieth the distance to the moon remains incomplete inspite of regular shuttle flight and the co-operation of 16 countries. In this context it is highly improbable that a habitable base on the moon will be built within the next 50 yrs. Chandrayan has a more modest completion date i.e. by 2008.

More importantly if robots are to be sent than a moon base itself is irrelevant. The robot will survive of solar power and will explore when it is fully charged. Why would we need a moon base.

- By Zero.

P.S.
The last post on the moon issue was by me. Didn't realize my name wouldn't show up.

Misson on moon.

I wrote a post before about the proposed manned mission on moon from India and a score of other nations. Then I told that there are few better options, rather than going for a manned mission on moon, and India should place a larger picture for the global audience. After all such things are just to show your international poweress.
NASA is now trying to make a permanent station on either of the poles of moon. It could have been ISRO's idea, if I would have been working with them. Yes it will take much more money than sending a man or two to the moon. But hey sending such rockets is not a monthly business, rather in many cases its a life time opportunity. So, tax more and make a thing which we can call The First. Moreover, to me, its a far better idea to set up a permanent station on moon, though not human, but robotic(NASA are going for manned station and I am not ready to pay that much tax).
It would certainly be working there for much more time than a human can work. And if some one tells me that India is not that good in robotics then I would like to remind them that Indian is possible to do any thing in a time span which is unimaginable by many others. We can easily develop robotics, more over this is era of multinational activities.

You can read my previous article here.
And a follow-up by my friend here.

Youth Against AIDS.

Today I am happy, very happy that I have materialized one of my old dream, a truly social site against HIV, that too free of cost. I thought about it in summer last year, then now nearly after year and half, when I am deep in social blogging, after materializing few of my other projects suddenly this old idea of mine struck me once again on another World AIDS Day. I dont know weather this idea of mine is unique or not, it doesn't matter, the thing which matter is that we will need lot of people, that to youth to mobilize whole world against AIDS.
So make your presence felt at Youth Against AIDS