Hearts

Actually I came across this quite some time back but never really understood why won't it work.

Wiki it if you need a memory jog~

anyway quote from wiki

 

Although at first sight the Brownian ratchet seems to extract useful work from Brownian motion, Feynman demonstrated that if the entire device is at the same temperature, the ratchet will not rotate continuously in one direction but will move randomly back and forth, and therefore will not produce any useful work. A simple way to visualize how the machine might fail is to remember that a ratchet and pawl small enough to move in response to individual molecular collisions also would be small enough to undergo Brownian motion as well. The pawl therefore will intermittently fail, allowing the ratchet to slip backward. Feynman demonstrated that if the temperature T₂ of the ratchet and pawl is the same as the temperature T₁ of the paddle, then the failure rate must equal the rate at which the ratchet ratchets forward, so that no net motion results over long enough periods or in an ensemble averaged sense.^[2] A simple but rigorous proof that no net motion occurs no matter what shape the teeth are was given by Magnasco. ^[3]

 

and from another site,http://www.elmer.unibas.ch/bm/index.html.

The energy does not come from the heat bath but from the ratchet potential when it is switched on. At that moment the potential energy of the particle will be suddenly increased. In the simulation this can be seen by a sudden increase of the energy bar. But most of the energy pushed into the system will be just dissipated into the heat bath due to the relaxation of the particle into a potential minima. Only a tiny portion will be used for doing work. Thus a Brownian motor does not violate any law of thermodynamics it only turns one type of work into another one.

I'm not entirely convinced yet though~

I thought thermo's second law don't work on extremely small scales..

can anyone explain the problem wih this motor?

Perhaps it was how they drew atoms in books or show on tv. It was based on a old model if I'm not mistaken, not extremely accurate but good for explaining things.

My chem teacher told me that the electrons are not necessarily located in the those fixed orbitals , they just are more probable to be there. Heck the electron of an atom could be halfway across the universe (or maybe I'm exegerating too much?) but it will be extremely unlikely. And yea, not all orbitals are spherical, only the S ones, if I remember.

I'm also rusty though, anyone feel free to correct me.

@Horza :Lol, are you seriously asking a 9th grader to invent a new drug?

Anyway I hope I'm not too late..

@Danis: I like Horza's idea on green energy. Maybe you can try making a solar cell (there are sites that will show you how, discuss with your teacher and get adult help!) or make a working model of a hydroelectric dam/ wind turbines. (hint: use a dynamo). Then you can discuss the viability of the greener energy of your project. Be warned ! Green energy may not be as green as you think, they all have cons, some of them may actually be far worse than your conventional coal fired plant. Do a little research. Who knows, maybe one day you'll end up doing this branch of science/engineering .

It's okay =) you've been a great help~

Really appreciate your efforts.

Thanks.

Other than your pressure-meter-at-regular-intervals (I can't believe I didn't think of that ), I also found out that they use a sensitive sound measuring/hearing device to detect underground leaks. Simple concept but I think determining the exact location of the leak depends largely on the skill of the person operating the device.

http://www.nrc-cnrc....s/ctus-n40.html

A person in my country on average consume around 300 litres of water a day!

Source: http://www.competiti...s/mcr05/lee.pdf (pg 6) and the words of my lecturer.

Assuming water demand haven't increased significantly for the last 5 years..

Pretty scary when considering that 6 litres of drinking water can keep me hydrated for a few days.

Btw, about the size of the project..

The system is to last for around 50 years.

Past data

year population

1980 3000

1990 5700

2000 6400

2010 9600

The village include

few Terrace houses

few Semi-D s

few Bungalows

few Apartments

one Mosque

one Daily school

one Boarding school

two Kindergartensfew Shop lots (single-storey)

two Petrol station

one Wet market

one Light industry workshop

I haven't actually calculated the water demand yet..I'm sorry for not making clear the size of this project.

Hope this gives you a rough idea ~

Going to see a lecturer with actual experience in this later =D

Wish me luck~ he can be a little unforgiving sometimes, especially to the ones that did not do their homework.

Forgive me but you haven't mention the reason why canals are preferred. I found out the closest river to the village is 4.6 kilometers away. I don't think it makes economic sense to cordon off that much length of land. (The people here use it to plant paddy/rice).

Btw I cant watch the video you linked.

My university believes youtube is bad for us.

hmm..okay..thanks for the pointer,

but why open air ducts (canals) are used? wouldn't it risk even more contamination?

The water recycling part is a good idea.. there are some paddy fields around the village that could use irrigation~

unproductive week anyway, got addicted to Heroes 5, and I suspect that I won't get any reply from 'guys responsible for the water distribution in the state'

hmm, underground pipes? They don't interfere with anything above ground cause they are well, underground, but should any of the pipe leak along the way, they will be a pain to detect and replace/repair, especially if something has already been built on top of it.

how do they do that anyway? Do they insert some sort of radioactive substance with short half lives and then check with a gieger counter?

Flocculation. The Nalgonda technique (named after the village in India where the method was pioneered) employs this principle. Alum (hydrate aluminium salts) - a coagulant commonly used for water treatment - is used to flocculate fluoride ions in the water. Since the process is best carried out under alkaline conditions, lime is added; bleaching powder can also be added to disinfect the water. After a thorough stirring, the chemical elements coagulate into flocs that are heavier than water and settle to the bottom of the container. The operation can be carried out on a large or small scale, and the technique is suitable for both community or household use. One household version uses a pair of 20-litre buckets, with a settling time of one hour and not more than two hours: after coagulation and settling are complete, the treated water is withdrawn through a tap 5 cm above the bottom of the first bucket, safely above the sludge level, and stored for the day's drinking in the second bucket.

 

• Adsorption. The other approach is to filter water down through a column packed with a strong adsorbent, such as activated alumina (Al2O3), activated charcoal, or ion exchange resins. This method, too, is suitable for both community and household use. When the adsorbent becomes saturated with fluoride ions, the filter material has to be backwashed with a mild acid or alkali solution to clean and regenerate it. The effluent from backwashing is rich in accumulated fluoride and must therefore be disposed of carefully to avoid recontaminating nearby groundwater.

Both the community and household defluoridation systems have pros and cons. Defluoridation equipment connected to a community handpump is theoretically cheaper per capita than a household unit because of economies of scale; but ensuring proper maintenance of a commonly owned facility is often problematic, so good community organization is necessary. The household units are more convenient for filtering the small amounts of water intended for drinking only, and people usually take better care of them; but an extensive and efficient service system is required to ensure that the filters are replaced or regenerated at the right time. Technology is only part of the issue: local capacity building, including entrepreneurial capabilities, can be a far more critical and difficult task.

source: http://www.nofluorid...nicef_fluor.htm

First, list down all the pros and cons of each 'solution-to-the-problem' you find.

Next pick the most practical one in terms of effectiveness, cost, availability, speed of treatment...

Find out how fluoride reacts with (chemical-u-wanna-use) to form the precipitate..

From your equation balance, determine how much of chemical-u-wanna-use you'll need.

check out the section on 'jar test'

pg 39, section 3 fluoride reduction here

http://www.ijcea.org...s/72-B30028.pdf

the rest were 'too long didn't read' for me though.

out of topic but I don't understand why would anyone consume gold..?

It shouldn't be tasty..should it?

Michel: Nope, I don't think so. Not this particular one anyway. Anyway it's a she and she's not a professor yet, still studying for it I think.

Sent an email to the guys responsible for the water distribution in the state. Still awaiting reply.

Meanwhile I'm googling stuff here and there~

I dread calculating head loss.

Anyway why is political map important? Can we pretend there's no red tape?

Captainpanic: about 'overdimensioning', I found..

Excessive capacity

The system should not have excessive capacity (which will result in long transit

times) unless this excess capacity is required to meet a known increase in future

demand.

source : http://www.who.int/water_sanitation_health/dwq/en/piped3.pdf

3. Design and operation of distribution networks

3.2 DESIGN AND OPERATION OF PIPED NETWORKS

3.2.1 Hydraulics

second paragraph.

Distribution pipes

..Since water pipes will be used for at least 50 years, most communities look ahead to expanded service and often use bigger pipe than the minimum. Too large a pipe, however, can lead to water quality problems. If water stands too long in large pipes, the chlorine residual diminishes, metals can dissolve in the water, and biological films can grow.

source: http://ohioline.osu.edu/b910/b910_13.html

Thx for the replies..it helped to get the ball rolling

1. Introduction

As engineer in the consultantfirm, your group are assigning to design a water supply system for the proposedhousing and public development project in Pauh, Perlis.

2. Scope of Work

The scope of work shallcomprise the following;

(a) ProjectDescription

(b) Populationprojection

© Computationof water demand

(d) ProposeWater Intake Collection and Water Intake Structure

(e) Determination of Water Quality Index (WQI)

(f) Proposeand design water treatment plant

(g) Proposewater distribution layout

3. Project Description

Shouldincludes; the purpose of design project, study of project area (such as projectlocation and existing environment i.e. land use, topography, geology and meteorology (wind profileand rainfall)) and projectelements (electricity, telecommunication, access road, drainage and sewerage.)

4. Population Projection

Previousdata from thepopulation and housing census done by Department of Statistics in Pauh, Perlis isgiven in the following table.

Year

Population

Assume the design years of the watersupply scheme. Choose one of the following methods of population projection andestimate your population:

i) arithmetic growth

ii) geometric growth

iii) incremental increase

iv) decreasing rate of increase

5. Water Demand

The daily water demand for thewhole development is ………….. L/day and is computed based on guideline providedby JBA Perlis:

Housing and Public Development

1.

Terrace house

2.

Semi-D

3.

Bungalow

4.

Apartment

5.

Mosque

6.

Daily school

7.

Boarding school

8.

Kindergarten

Total

Trade Development

1.

Shop lots (single-storey)

2.

Petrol station

3.

Wet market

4.

Light industry workshop

Total

6. Water Demand Fluctuations

Average annual demand is not sufficient for design ofwater systems due to water demand fluctuations. Generally, monthly fluctuation is used for design of damand storage tank. Flow of water required during maximum daily demand can beused to design water treatment plant, while flow required at peak hour demandcan be used for design of water distribution system (pumping, service tank,water mains).

Given:

Maximum daily demand = 180% of annual average demand

Maximum weekly demand = 148% of annual average demand

Maximum monthly demand = 128% of annual average demand

Maximum hourly demand = 150% of maximum daily demand

6. Propose Water Intake Collection and WaterIntake Structure

- Type of water collection: justify your selection

-Type of water intake structure: justify your selection

7. Determination of Water Quality

Water quality studyis an important criterion in the design of water treatment plant. Therefore,each group of student is needed to carry out field work by collecting “river water sample”for the analysis of its waterquality. All the parameters that been selected should can be calculated for the WaterQuality Index (WQI). Therefore, each group of student is required to classifythe water quality level for the selected “river water sample” based on theresult obtained from the WQI.

8. Propose Water Treatment System

Prepare a design for the proposed water treatment systemat new housing and public development project in Pauh, Perlis. A design should include an estimate of the flow tobe treated, the water quality of the water, specification of the unit processesto be included in the treatment system, the size of the treatment units (i.e.,dimensions, flow capacities, etc.), and an estimate of the water quality thatwould result from the system.

9. Propose Water DistributionSystem

Should includes, description ofmethod and layout water distribution system, description of material used indistribution system and prepare overall layout of water distribution.

Mined some really useful notes from a forgotten part in my computer. Happy

@michel123456 : Unfortunately, estimating population growth IS part of the question

Predicting water demand due to future development of the area wasn't really asked but the lecturer did mention the importance of it in one of his classes.

Estimating the water demand has been taught, but we only know it in theory.

The lecturer will give us the data soon.

The business aspect of it is something I don't want to go into either (and it's not asked anyway). Had a brief course on engineering entrepreneurship back a while ago, but due to general disinterest in the subject, I came away with nothing more than a slide show and format for a business plan.

@CaptainPanic :

Due to the little resource we have (Google and books from the library we hardly understand), We are allowed to make some of the data up. It must be believable though. Here's a map of the area. A, (kampung ulu pauh) is the village we want to provide water for. The river doesn't look feasible from here, too many obstacles. The lake though..hmm..wad do u think?

Anyway I think the village should already has its own water supply and distribution system and I'm still looking it up. Nothing relevant appeared yet though.

I think I'll start with estimating the water demand first~

how would I know if the population growth follows an arithmetic or a geometric progression? (I can get past data, not much of it though,)

and If I want the system to last for a long time, how far ahead can I safely predict the numbers?

I have to leave room for possible development of the area in the future too. How can I do this practically?

Did try googling them, but only very simple cases (involves nothing more than just plugging numbers into the equation) turned up.

For our assignment, we have to design a system that will draw water from a source, calculate it's quality, treat it and then distribute it.

I'm not really sure where to start or what to do and would really appreciate guidance on what to do.

what are trace quantities?

...

I would suggest you try googling it first.

hmm... got some digesting to do~

Hmm, now I think that most, if not all of our definitions (of anything) are just expressions of it in other terms. And since concepts like time, space, matter and energy are so fundamental in nature that expressing them in other terms (defining it) is impossible. But if there are no proper way of telling what they really are, how come there are so much physics revolving these concepts?

Hmm,

@mr skeptic: I can't help but feel that your definition of space is akin to defining time as....

the second has been defined to be

the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.~ wikipedia

I probably misunderstood~

ah I see..

is there any formal definition of space? I know not everyone agreed on one for time yet...

any useful (beginner-friendly) links on this for me? my physics is kinda rusty.

Much appreciated and thanks

Why isn't time considered another dimension of space?

 

Hi Newbies_Kid,

Where did you get the information regarding disappearing airships?

Actually I think he meant ships( that travel on water). The term (air)plane is more commonly used nowadays (at least, in my environment)~

I did hear about disappearing planes~ which disappear without even trying to radio for help...spooky

Anyway~ back to topic please.

@dragonstar: Shaping the pipe like a funnel sounds a lil impratical to me. Are there people already doing this?

If everything must have a beginning, then all beginnings should have beginnings. It means at one point before the beginnings of beginnings, there are no beginnings? Paradoxical.

Anyway back to topic,

First law of thermodynamics. It is not known, nor will it ever be..if the law is actually wrong. Though it has been right so far...and likely to be right all along. Hmm..but one does wonder....

Stop going by car or motorbike, just walk

Well, you forgot to add the time factor in~

what if I can plant a tree/ find a viable alternative energy option/save the entire earth from Global warming/etc etc using the time that would otherwise be wasted if I walked to class instead of taking the bus?

If you look at oil and coal, the theory goes that these were produced by the remains of living organisms over long periods of time. What that means is all the basic components of oil and coal were formerly part of the earth, including all the CO2 that results when we burn these things.

 

When oil burns, we are returning the CO2 back to the earth where it originally came; natural part of the earth. That period of earth history, when all these materials were not yet oil and coal, was not a time of earth destruction. It was a time of earth fertility, producing abundant life that would alter these simple materials into those junkyards of dead life we call oil and coal deposits. Therefore putting this material back to its original state, before life created these dumps and boneyards, would not destroy the world, but simply restore the world to an earlier pristine time when there no such landfills and dumps.

 

The bottom line is fear of change, using the assumption now is the perfect time of the earth. Through rhetoric, reality is distorted to create those misleading messages of world destruction. But as history shows, when all this material was spread over the earth, in simple forms, the earth was not destroyed. The earth was fertile with a potential for change. The earth was pristine with no junk yards of oil and coal.

Co2 is a gas ~ but thats not the point here anyway.

Frankly pioneer, the whole point of environmental preservation/ engineering and all related fields is to make our human lives ( and we might as well include the other critters that roam the earth) comfortable and sustainable. We are trying to save ourselves, not the earth. Imagine the earth without us. Even if it spew lava from every pore and its atmosphere is nothing but methane and co2, it would still be perfectly 'natural' and the minerals there wont complain anyway.

Eat self-cultured food as possible as we can, that is best way to reduce pollution. And wear self-made dress. Let us live in the country. Efficient life make our Earth more polluted.

Our small S(entropy) life makes our surroundings more big entropy state. So it is not easy to reduce pollution.

Back to simpler times eh? well, our population has increased a millionfold since then and not all of us can afford a big enough space for country life now. Contrary to your intuitive, 'efficient life' is better than inefficient life because otherwise we would be wasting energy. Remember energy cannot be destroyed but it only moves one way~ tat is towards increasing entropy, or decreasing 'quality'. So it would be best if we make full use of our energy now before it all becomes useless.

What more can be done to preventing volcanic eruptions?

I thought we cannot prevent them, but at least we can avoid them?

Yes, we can at least avoid them.

Anyway, I feel that if we are able to control where the magma will spill out, besides saving human lives and protecting property, we could create new land ( to relieve the population problem). I've heard that the ground near volcanoes are fertile...so if we do it just right, we could also make a few farmers happy, grow more food to feed us overpopulated humans. As for the problem of the melting drill, why not design it to be single use only? I don't imagine it to have much more of a lifespan anyway if its made to do such heavy work. The new fertile land could help justify the economical aspect of this undoubtly expensive project.

GRAVITY TO ELECTRICAL GENERATION?

PRETTY SIMPLE...PICTURE A BOAT BOBBING OVER THE WAVES IN AN OCEAN..

PICTURE THIS SAME BOAT BOBBING OVER THE WAVES IN AN OCEAN WITH A STRONG WIND.

NOW USE THIS ENERGY...STYROFOAM FLOAT AFFIXED TO A POLE HELD IN PLACE BY BURYING IT IN CONCRETE AT THE BOTTOM OF THE OCEAN, LAKE ETC...

OR SOMETHING SIMILAR LIKE AN AIR FILLED BALL, THAT CAN SLIDE UP AND DOWN THE POLE...A LARGE BALL, HEAVY YET FLOATS, CONNECTED TO AN ARM MAYBE, LIKE A ROCKER ARM IN AN ENGINE THAT DRIVES THE GENERATOR...

VERY MUCH THE SAME MECHANICALS THAT ARE USUED FOR OIL FIELD PUMPS..

WELL? CAN IT WORK..

WOULD LIKE TO HEAR BACK FROM THE EDUCATED ENGINEERS OUT THERE..

My father once told me that fishermen use to tie their boats to poles at high tide. Then at low tide, the weight of the boat(s) will drag the pole down, pushing it into the seabed. They would repeat this process untill the pole got in as deep as they like. Why would they do that? I never asked, prolly so that they have something to tie their boats to or to construct a shaky house/restaurant later on.