Archive for the ‘Technology’ Category

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Aluminium

Saturday, May 10th, 2008

Prising elements out of the Earth’s crust, purifying their essence and moulding them into crafts highlights the technical age of humanity. Steel becomes ploughshares, silicon melts into transistors and aluminium shines into pots and pans. By learning the characteristics of many elements and compounds, humans specialize material into being capable aids to our everyday existence.

Yet, no wizard’s wand transforms rock. Human labour, our sweat and skill, do it. However, somewhat magically, machines aid our tolling. Great shovels dig dirt, roaring blast furnaces separate and shape the elements. As such, aluminium requires about 200 MJ for every kilogram produced (Smil, 2008).

The world production of aluminium in 2007 was 36 000 thousand metric tons (USGS). In total then, we used about 7.2e18 joules of energy to transform the Earth’s material into our devices. That’s 1.58% of the global total of primary energy usage. In other words, we consider one element to be so precious that we allocate 1.58% of our annual supplies of non-renewable energy resources to extract it.

And, what do we do with it? In the U.S., the partition was; 38% transportation, 22% packaging, 16 % buildings, 7% electrical, 7% machinery, 7% consumer durables, and 3% others (USGS). Is this the best distribution of our energy resources? If supplies fail to meet demand, how should the partitioning change?

Ingot

Photo Alupro

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Library of Alexandria

Friday, April 11th, 2008

Gold makes peoples’ eyes widen with desire. Platinum excites those with a richer taste. Greater than both these is knowledge. Skilled craftsmen turn metal into fiery chariots that carry humans to space. A touch on a keyboard lays before us the depths of our existence. With it, humans are the most advanced species on the planet. Without it, we suffer causal existence.

Many years ago, the Greeks extolled the value of knowledge. From this eagerness arose the Royal Library of the Ptolemies. For hundreds of years this developed and flourished to become the cornerstone of the Great Library of Alexandria. This amazing institute brought scholars and information together. Sadly, its contribution is less clear.

In its days the library usually used papyrus scrolls to record information. Assume a scroll had an area of about a metre by a metre and was about a millimetre thick. With 500 000 scrolls, the library had about 500 cubic metres of papyrus which has a mass of about 50 000kg. In burning (as was said to be the fate of the library), this releases about 5.4e10 joules of energy.

Yet, the library had about 40 full time scholars and a vast complex to record and preserve data. Their dietary energy requirements over 300 hundred years is nearly 5e13 joules. The energy costs for making the paper and ink and acquiring the information is much extra. Apparently, just recording the information cost a thousand times more energy than the storage medium. Filtering and dissemination were activities not yet accrued.

Some estimates put the information content on the Internet at a few thousand petabytes (1e18) and growing. Without electricity to maintain the Internet, what becomes of the information? How will we record our knowledge in the future? Or, must we ensure available electricity (energy) at any cost?

Alexandria

Photo University of Texas

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Earth Hour

Monday, March 24th, 2008

A hectic rush becomes synonymous with our daily passage through another day. We allocate less time to enjoy simple pleasures and more time to complete the to-do list. Recover a sense of balance by stepping away from the treadmill. On a personal scale, we close our eyes and meditate. On a global scale, there’s Earth Hour.

The simple act of darkening a light bulb has many consequences. If we let darkness envelope us then we can’t be distracted by reading or watching television. Extending our senses, we can envision the consequences of everyday energy shortfalls. Work and entertainment would get limited to daylights hours. Nightfall could bring on quiet reflection.

According to British Petroleum’s statistical review, in 2006 we used about 4.6e20 joules of primary energy (oil, coal, gas, nuclear, hydro). There are 8760 hours in a year. Assume we use the same amount of energy in 2008. And, assume humans use no energy for one hour. Then, we would relinquish 5.2e16 joules of energy. This is the typical wood harvest from 4e9 acres of woodlot (assuming 5 cords of wood each acre every ten years). The province of Ontario, larger than France and Spain combined, has 2e8 acres of forest. Hence, one hour of humanity’s energy consumption is equal to the energy from forests 20 times larger than the one covering most of this province.

Perhaps, taking an hour to think about this situation may set people’s minds to thinking about energy sources that will continue long after the fossil fuels have been consumed. This eventuality may come sooner than we expect.

Earth Hour

Forest

Photo from Massachusetts.gov

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Niagara Falls

Thursday, January 31st, 2008

A wonder of the natural world amazes us as 5796 cubic metres of water each second drop 99 metres along the length of the Niagara River. Before 1896, this huge release of energy had the minimal effect of slightly warming the water. However, with the diversion of water, humans now use some of the river to generate 1.4e17 Joules of electrical potential each year at Niagara Falls.

Humans with a standard of living that consumes large amounts of current technology, like North America and Europe, use about 3.4e11 Joules of energy per person each year, not including dietary needs. Thus, the energy from Niagara Falls could maintain about half a million people at this life styles.

It is with no surprise that people flocked to the Niagara Falls area to take advantage of this free energy. Yet, over 2 million people now live within 50 kilometres of the falls. That is, four times the number of people live in the immediate vicinity of the falls than can be supported by the energy derived from the falls.

Though Niagara Falls should continue providing energy for a long time into the future, it is insufficient on its own to meet current demands. Should alternative energy supplies be no longer forth coming, e.g. petroleum supplies cease, then either the number of people in the area must decrease or the living standard must decrease. Should plans be formulated for this or should we wait and see?

Niagara Falls nearly frozen dry in 1912;

Frozen Niagara.

Photo from the Niagara Falls Public Library

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Iron Swords

Friday, January 4th, 2008

Humankind’s Iron Age signifies another technological leap. Using knowledge gained from smelting soft copper and tin into bronze, we started smelting the vast quantities of iron that permeate the Earth’s crust. Out of the forges came wonderful fabrications such as nails, bolts, horseshoes, shields and swords. Forcing rocks into special utilitarian shapes facilitated the endavours of humans and made our species even more successful.

However, iron working was neither simple or cheap. A source of iron (like Magnetite – Fe3O4) had to be found and then mined. Then, the rock had to be purified by removing the oxygen and other unwanted material. A bloomery, or oven, heated the rock so as to force out the unwanted atoms. Introducing charcoal facilitates this process as the charcoal, or carbon, combines with the oxygen to make gaseous carbon dioxide and carbon monoxide which drifts away. The resulting sponge like mass, called a bloom, was again heated and hammered to continue with the removal of impurities and to shape the rock. The result, known as wrought iron, was well on its way to becoming an implement ready for humankind’s desires.

But this process had a high energy cost. Human labour dug the rock, carried it to the bloomery, and hammered the impurities out. Heating the rock (to about 1600C) required large quantities of wood. Most of all though was the charcoal cost. Charcoals is made by roasting wood. Therefore, wood was needed for both the roasting and to be roasted. This energy hungry process caused the denuding of the medieval European landscape.

The Cornwall bloomery consumed 340 acres of wood per year to produce 1000 tons of iron. Neglect the energy costs for the labour and the infrastructure. And, assume this bloomery used virgin, mature stands of trees with about 50 trees per hectare each about 50 metres in height. Using typical energy density values for trees, this results in 8e9 joules (8 GJ) of energy to produce one kilogram of iron.

In 2005 we produced approximately 1544 million metric tons of iron ore. If we still used trees as the energy (and chemical) source we’d need 72 million trees or 1.5 million hectares. Or, we would if this area of mature forest still existed. And, this is for one year’s worth of swords, ploughshares and every other iron implement.

The leaps we’ve accomplished with technology come at a cost. Maintaining a ready supply of iron gives us great quantities of durable goods. But iron will return to its oxidized state eventually. Hence their replacements require a continual energy supply. And, more people with more demands increase the requirements and thus the energy needs. Can we sustain the necessary energy supply to keep us at our desired technological level?

Cornwall

Sword

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