Lead acid batteries

Lead acid batteries are widely used in UPSes and in automobiles. Unlike the more sophisticated brethren, like, say, the lithium polymer battery, the lead acid battery is not supported by chips and software. The onus of maintaining the battery falls on the user. What can be done if the battery has not been charged for a while? The usual case is a battery which cannot be charged at all, so that you can give it back and claim whatever recycling credit your locality offers. However, there are circuits available that will attempt to rejuvenate the battery. This consists of circuits which send in a pulsed current to induce changes in the battery structure. The parameters for this operation are not clear, as there is no off the shelf solution. Various hobbyist designs are available.

The high density of lead makes the transportation of the batteries difficult. Perhaps it is also a security measure for car batteries–they cannot be easily stolen :-).

Plant Physics

Plants produce oxygen from carbon dioxide during photosynthesis during the day. At night, they produce carbon dioxide. Some claim that you should not have a plant in your bedroom. Or that if you have one, you should move it out at night. The reason given is that they produce carbon dioxide which is harmful to you. However, the question to be asked is, how much carbon dioxide is produced? A plant that is about a foot tall, will weigh only a few hundred grams at worst. Considering that mammals produce gases in proportion to their body mass, the amount produced should be minuscule indeed. In fact, if you are so worried about carbon dioxide in the room, you should sleep alone! To put some numbers here, we have the oxygen consumption at about 200 gal during one night for an adult human being. This is around 10 % of the mass of the gas in an average room. BTW, this also underlines the importance of ventilation. Consider the reaction C6H12O6 + 6O2 = 6CO2 + 6H2O. In this case, the amount of CO2 produced is 44/32 times the O2 consumed, around 2.5 lbs.

Plants require nutrients from the soil: namely nitrogen, phosphorous and potassium. In addition, they also need micro-nutrients. Natural fertilizer include mulch, which is organic matter which will decay and give nutrients to the soil. They also retain moisture, so that watering needs are reduced. Before planting, you will need to test the soil to see the pH etc. A better way is to have raised beds where you can add store bought soil, which will give you a much shallower learning curve. Note that compost has a lead time of 3 to 12 months.

Back to Metal!

Plastics are a pervasive feature of modern life. If you take a look around you as you are reading this, you would find more plastic components than metal. Plastic is so cheap to produce and to manufacture, most of the throwaway items that you get is also made of plastic. However, recycling plastic is entirely another issue. Since there is such a large variety of plastics in the market, it cannot really be recycled, and has to be buried in landfills.

How can you deal with the above situation? First of all, when offered some gadget or knick-knack which is of questionable value to you, just say no. If you use a plastic pen, make sure you get one without the rubber parts so that you don’t have to throw it away after a couple of months when it starts to rot. If offered some plastic bags to carry your purchase, see if you can carry it without it. Many machines now come with rubber bushes rather than metal springs. These need frequent replacement, which is a hassle and a drain on your wallet. If you have a choice, go for the solid metal one.

Plastic movable components are really a recipe for disaster. USB drives of the slider type are a good example. Perhaps all is not lost–many systems can have the plastic parts replaced with metal. Of course, this implies a good machining center to get the tolerances required.

This brings me to the main idea in this post–namely, replace as many plastic parts with metal! What if you have to throw away a metal part, you ask? Well, feel free to do so–there is always someone who can make a living off that scrap. It is actually profitable to extract metal from scrap and reuse it.

Another material which can replace plastic is wood. Now, wooden parts are not so easy to manufacture as plastic ones, and this would definitely limit the kind of products which you could avail, but every little step is important. Note, however, that when wood is used to build something in these modern times, there are add-ons that you would not have expected hundred years ago. Wood is treated with chemicals which are not exactly environment friendly to prevent it from drying out too fast after cutting (fast drying causes splits). The recommended material for coating wooden furniture these days is plastic! So you can’t really throw away your broken wooden furniture or burn it—it has to be recycled like plastics.

Many metals can be recycled almost completely—the lead in storage batteries comes to mind. With the current level of inflation, it would not be surprising to get more money out of a well maintained battery than what you originally paid for it.

One way you yourself can reuse metal is by melting it. One useful metal which has really low melting point is aluminum. It melts around 1400 F, and is lightweight and corrosion proof. Until about a 100 years ago, it was a rare metal, but now it is ubiquitous and cheap. Aluminum sand casting can produce many structural parts for day to day use.

Renewable Energy

There has been many an attempt made to produce the so called renewable energy. The machines required for this need to have certain characteristics–namely, the ability to work without wear and tear for a long time. An automobile or a lawn mower engine, with its limited duty cycle will simply not do. A modern car is designed to work for about 4000 hours between major overhauls.

Eco-Friendly Vehicles?

Another trend in hyping of these new fangled machines is the undue importance given to the most “eco-friendly” component of the system.

Hybrids

A hybrid is considered more environmentally benign choice compared to the standard gasoline engine. However, consider this–the hybrid is really two machines in one, and instead of driving a single car, you are now simultaneously driving two! The environmental impact of manufacturing a single car would be enormous. In fact, several sources give the amount of money that you might spend on gas in the couple of years you own a car–considering a reasonable distance of 30,000 miles, you would spend less than $5k even at the highest prices. This means that the cost of the vehicle, which is mostly manufacturing cost, would be about an order of magnitude larger than the fuel cost. Since the energy cost is significant factor in determining the manufacturing cost, this is definitely something to be considered during purchase.

Regenerative Braking

Another much touted feature in such cars is regenerative braking. Whereas you need energy to accelerate your car, you can theoretically get it back when braking. These cars claim to have brakes that will feed the energy into batteries while braking improving fuel efficiency. However, this needs some qualification—it is only available if you brake gently. In that case you might

Historical Energy Sources

A common sight in the middle ages was the truly renewable energy source of a dog wheel. A small dog would be made to run inside a giant hamster wheel. Now, we make jokes about things powered by hamsters, but the few watts produced by a small canine was very useful in those days. Farmers used small animals like sheep to run small machines, the ones that did not require “horse power”. Here the animal walks on an inclined tread mill, which drives a small machine.

The earliest machines were powered by water, and it was used to power fountains and carry water from a lower level to a higher level. Hopefully, the source of water was a stable one, like the palaces of Louis XIV in Versailles. Some of the kingdoms in south east Asia were not so fortunate, the river having shifted course, rendering their elaborate constructions useless.

Inherent Inefficiencies of Local Power Generation

Small machines inherently have greater frictional resistance when operated in a piston cylinder arrangement. Large machines have their own problems, mainly the manufacture of such large cylinders and fitting pistons. However, since the surface area per unit volume for the smaller machines were much larger, the frictional losses were larger too.

Limitations

The amount of free space available on free webmail providers, and the free photo sites has been increasing to GB levels. The kind of content that can be posted is quite narrow however. Blogs are good for rants and the like, but unless there is something like pinning a blog as you would find in some web boards, it has limited utility. Photo sites seem to have started off to make money out of prints of photos, but they now seem to work on the network effect (volume will pay). This is quite dubious, but considering how the cost of storage is falling, not that outlandish. On the other hand, Yahoo seems to have abandoned geocities altogether, with the amount of space there stuck at 15 MB forever. I find that there are some sites offering 1 GB, but I don’t see much being written about it. But then, how much content can you really generate? If you are into video, there is always Youtube, which provides unlimited storage. Note that Youtube is afflicted with Google’s obsession with storing every little thing that you do.

Search Engines

Google

Automated searching may get you the exact opposite of what you are looking for . A search in Google for “aspire one benchmark linux” has a bunch of links from CNET which talks about “the couldn’t run a benchmark on aspire one. ” Here Google outdoes itself by getting you the exact opposite of what you want. Keep up the good work!

I have the following theory about why the search quality is so bad: it is function of what people are searching for. If you look at the main pages at MSN or Yahoo, we can see that most of the search terms are the names of celebrities, and the “engine” doesn’t really have to do much work. What is pretty bad is that the bulk of the revenue of the search sites come from such searches, and they really don’t need to improve these other “marginal” searches to be effective. Specific technical queries in Google are really hopeless.

Cloud Computing

Cloud computing is a new term for a concept which is seen to be a big application of Web 2.0—namely running apps on the web. Now we have the application as well as the data stored on remote servers. If this sounds like a really bad idea to you, you are not alone.
While fierce competition has forced blogging sites to be very open about the data, this will not be the case for the kinds of software that are hosted in the “Cloud”. The only way to use the data would be to have the same apps running locally, which may not be possible technically or legally. If the company goes belly-up, are you supposed to run your own server with that software? When Sun was planning to release some code, they claimed that it was not possible because they had to get a release for every last bit of code that they had. Just look at the delay in getting Sun’s JDK into mainstream Linux distributions after it had become “open source”.

School Arithmetic

The product rule – x – = + is taught in schools without proof. While a geometric proof may be messy, it is easy to see that (1 – 1)x(1 – 1) = 0 x 0 = 0, so that -1 x -1 = 1. This is enough to show that the product of any two negative numbers m and n is positive, as m can be expressed as -1x -m, where -m is positive. While you may think that this proof is rather naive, whereas correct treatments are found elsewhere, for instance Russell’s Principia Mathematica, where 2+2 = 4 is proved in 1200 pages, it should be pointed out that the great Euler also provided the proof in his book (never mind that he was widely ridiculed for it).

The reluctance to deal with negative numbers is a common occurrence in the school system. One example is a ball thrown up from the ground. Using negative numbers, the same formula can be used for the entire duration of flight, but “positivists” will split this into two, complicating matters. Another example is the sum to n terms of the geometric series with first term ‘a’ and common ratio ‘r’. The formula can be expressed as a(1-r^n)/(1-r). However, this is given as _two_ formulas, the other one being a(r^n -1)/(r-1) in order to avoid division by a negative number.

Another aspect of teaching math in school is the emphasis on the visual approach as more advanced or “modern”. While many people may think visually, there are others who find it more difficult than solving the original problem. The abacus based learning methods would be one way of performing this visual learning. The proponents of such tools posit that this is faster even as a general purpose computational tool. However, as Feynman has pointed out in his autobiography, computations are much faster if your mathematical background is wider. For instance, the cube root of 1729 would be very easy to compute using series expansion.

DSLR

The fundamental problem with dSLRs is that it has a moving mechanical component which adds to the vibration.  Why have a separate viewfinder and the whole swiveling lens mechanism when you can just see the image you are about to capture on the LCD?  Still, most of the experienced users swear that they will never buy a camera without a viewfinder.  Alas, as Max Planck pointed out, the only way for new ideas to get accepted is for old proponents to die. I look forward to the day non-SLR cameras have all the advanced features that go into a dSLR without the drawback of the movable prism.