IELTS Academic Reading Practice Test 143

In the last decades of the nineteenth century, the industrial world ran on steam. Steam engines drove locomotives, ships and factories, but they wasted most of the energy in their fuel: even the best designs turned perhaps a tenth of it into useful work, and the rest escaped as heat. Efficiency was limited by the temperature the boiler could withstand. Rudolf Diesel, a German engineer, became convinced that an engine of a different kind could do considerably better.

Diesel was born in Paris in 1858 to German parents and trained as a mechanical engineer in Munich. His early career was spent not with engines but in refrigeration, designing machines that cooled air and, in some cases, compressed it to very high pressures. That experience shaped his thinking, and so did the teaching of Carl von Linde, the refrigeration pioneer who insisted on the importance of thermodynamics. In the early 1890s Diesel set out to build an engine in which air alone would be squeezed so hard that it became hot enough to ignite fuel, a process later known as compression ignition.

Diesel patented the idea in 1892 and published a short book describing it the following year. The theory was elegant, but turning it into metal proved far harder. The first experimental engines were fragile and unpredictable: one ran under its own power for no more than a minute before it failed. Years of redesign followed, with Diesel and his assistants rebuilding pistons, valves and fuel systems again and again. The work was financed by two engineering firms, Maschinenfabrik Augsburg and Krupp, which supported the experiments for several years.

In 1897, at the Augsburg works, Diesel demonstrated an engine that finally justified the effort. It produced about 25 horsepower and converted roughly a quarter of the energy in its fuel into mechanical work, well over twice the efficiency of the best steam engines of the day. Licences to build diesel engines were quickly sold to manufacturers in several countries. The machine was heavy and ran slowly, but for the first time an internal combustion engine could compete with steam on running costs.

A petrol engine draws a mixture of fuel and air into a cylinder and ignites it with an electric spark. A diesel engine does something close to the opposite. Its cylinder takes in air alone, and the piston compresses that air to roughly a fifteenth or a twentieth of its original volume. Compression on this scale raises the temperature of the air to more than 500°C, far hotter than the point at which diesel fuel will burn. When fuel is sprayed into the cylinder at the end of the compression stroke it ignites on its own. The engine needs no ignition system at all.

Most vehicle engines run on a four-stroke cycle. On the first stroke the piston travels down and air is drawn in through an open valve. On the second it rises, closing the valve and squeezing the air. On the third, the power stroke, fuel is injected and burns, and the expanding gases force the piston down. On the fourth the piston rises once more, pushing the burnt gases out through the exhaust valve. A four-cylinder engine staggers these strokes so that one cylinder is always delivering power.

Diesel intended his engine to run on whatever fuel was cheapest and most easily obtained, and he experimented widely. Coal dust was tried and abandoned after it proved abrasive and dangerous. At the Paris Exposition of 1900 one of his engines was run on peanut oil, a demonstration that interested countries with little access to petroleum. In 1912 he remarked that the use of vegetable oils as fuel might seem insignificant at the time but could in future become as important as petroleum.

Diesel did not live to see his engine dominate any form of transport. In September 1913 he boarded the steamer Dresden to cross the English Channel and disappeared during the voyage; his body was found in the water some days later, and the circumstances have never been explained satisfactorily. The engine's early progress was slow, because it was heavy, costly to build and demanding of clean fuel. Its first great success came at sea: in 1912 a Danish cargo ship, the Selandia, had become the first ocean-going vessel powered by diesel engines, and navies soon took an interest.

Two developments transformed the engine during the twentieth century. The first was turbocharging, patented in 1905 by the Swiss engineer Alfred Büchi, which uses the energy of the exhaust gases to drive a turbine that forces more air into the cylinder. The second was the arrival in the 1920s of compact high-speed fuel-injection pumps, which made small diesel engines practical for lorries and buses. By the middle of the century the diesel had become the standard power unit for heavy road transport and for ships.

Modern diesel engines are the most efficient practical engines for road and sea transport. Large marine versions convert more than half of the energy in their fuel into motion, and car engines can approach 45 per cent under favourable conditions. Their weakness is the exhaust. Because the fuel burns unevenly, diesel engines produce nitrogen oxides and tiny particles of soot, both of which damage human health. Modern vehicles therefore carry filters and treatment systems for these pollutants, and the revelation in 2015 that the Volkswagen group had used software to evade emissions tests in the United States damaged the engine's reputation.

Few products are discarded as quickly as electronic ones. A mobile phone may be kept for two or three years, a laptop for four or five, and a television for longer, but all of them eventually join a growing mountain of waste. The most recent global estimate put the annual total at about 62 million tonnes, a figure rising several times faster than the world's population. Less than a quarter of that mass was documented as collected and properly recycled; the rest was stored in cupboards, buried in landfill or handled by informal workers. The raw materials locked up in this waste are reckoned to be worth tens of billions of dollars every year. Europe generates the most per person, while the fastest growth is in countries where households are acquiring their first refrigerators and air conditioners.

Collection is the weakest link. Even in countries with modern recycling plants, the plants often run below capacity, because so much old equipment is left in drawers, exported illegally or thrown out with ordinary rubbish. Persuading people to part with a working device is proving harder than building a factory to process it.

The reason electronic waste is both a problem and an opportunity lies in what it contains. A single smartphone holds dozens of chemical elements: copper in its wiring, aluminium in its frame, gold and silver in minute quantities on its circuit boards, cobalt in its battery and small amounts of rare earth elements in its screen and speaker. Printed circuit boards are commonly many times richer in gold than the ore taken from a working gold mine. The same devices also contain lead, mercury, cadmium and brominated flame retardants, substances that are hazardous in themselves and become more so when they are burned or dissolved.

Recycling such an object is not simply a matter of melting it down. Devices are designed for performance and for miniaturisation, not for disassembly: batteries are glued into place, components are soldered to boards that may contain a dozen different materials, and the valuable metals are dispersed in quantities too small to be picked out one by one. A process that extracts one material efficiently may make another harder to recover.

The first stage of formal recycling is mechanical. Collected equipment is sorted, and batteries are taken out by hand before they can catch fire or contaminate everything else. The remaining equipment is shredded and then separated by physical means: strong magnets lift out steel, rapidly changing magnetic fields induce currents in aluminium and flick it away from the plastics, and tanks of liquid divide the fragments by density. What emerges is a set of concentrates, each of which must be treated separately.

The oldest and still the most widely used treatment for circuit boards is smelting. Concentrates are fed into a furnace at temperatures above 1,000°C, where the plastics burn away and copper, gold, silver and palladium collect in a molten metal layer. The method is robust and accepts almost any mixture, but it is energy-hungry and undiscriminating: aluminium and lithium, together with much of the glass and ceramic material, end up in the slag, from which they are rarely recovered.

Hydrometallurgy offers a more selective alternative. Instead of heat it uses liquids: the circuits are dissolved in acids or other solvents, and the metals are then separated from one another by chemical means. Because the process runs at modest temperatures and can be tuned to particular metals, it recovers a wider range of materials and consumes less energy than smelting. Its drawback is the large volume of liquid waste it produces, which must itself be treated, and the difficulty of applying it to very mixed material.

A great deal of recycling happens outside such facilities. In parts of West Africa and South-East Asia, workers buy discarded equipment, break it apart by hand, burn cables in the open air to recover copper and use acid to strip gold from circuit boards. The practice recovers metals at very low cost and supports thousands of families, but it releases toxic fumes and leaves contaminated soil and water. Lead and mercury from the waste accumulate in the workers and in the children who live beside the yards.

Researchers are trying to replace these methods with gentler ones. Certain bacteria and fungi produce acids that dissolve metals from waste at ordinary temperatures and pressures. Bioleaching has been used for decades to extract copper from low-grade ore, and laboratories have shown that it can also release metals from circuit boards and spent batteries. Some teams are now testing whether the same organisms can recover rare earth elements, which are among the least recycled of all materials and are currently produced mainly in China. The technique is slow, however, and has so far been demonstrated only at small scale.

The more radical suggestion is to design waste out of the system. One small Dutch manufacturer sells a phone whose parts the owner can replace with a screwdriver, and France now requires electrical goods to carry a score showing how easy they are to repair. Longer use is, on any calculation, more effective than recycling: the greenest device is the one that is never replaced.

Every few years the question resurfaces: can video games be art? In 2010 the American film critic Roger Ebert answered it in a blog post with an emphatic no. He had, he wrote, never encountered a game that affected him as great films, poetry or music had, and he doubted that the medium could ever produce such an experience. The post provoked a storm of comment. More than a decade later the argument is no closer to resolution, and the reason, I think, is that both sides have been asking the wrong question.

The strongest objection to calling games art rests on the role of the player. A novel, a painting or a symphony is complete before its audience arrives; a game is not. Someone has to press the buttons, and what appears on the screen depends on how well, how quickly and how imaginatively that person acts. A clumsy reader may miss the beauty of a paragraph, but a clumsy player may never reach the part where the beauty begins. The designer, on this argument, surrenders control of the work to someone whose ability and commitment are unknown.

This objection is more interesting than it first appears, but it does not separate games from the other arts as cleanly as its supporters suppose. A score is not a symphony; it becomes one only when musicians play it, and a poor orchestra can ruin a masterpiece. Theatre depends on the actors of the evening, and no two performances of a play are ever quite the same. What distinguishes games is the extent of the audience's contribution, not its existence. Games are unusual in asking that audience to make decisions, but they are not unique in requiring it to do something.

A second objection is that games are made to be sold and to be fun, and that entertainment and commerce are incompatible with art. This is a strange argument to make about a medium that includes the novel. Dickens published his novels in instalments for a mass readership and was paid by the word; Shakespeare wrote for a popular theatre that needed to fill its seats. Neither is thought less of for it. Commercial motives may explain why a work was made, but they do not determine whether it is any good.

The positive case is stronger than either objection suggests, and it rests on what games can do that other media cannot. A game is built from rules, and rules can carry meaning as surely as sentences or brushstrokes. In a game about a border post, the player must decide which travellers to admit while supporting a family on a meagre salary; the difficulty of that decision is not described in dialogue but built into the mechanics. The player feels the pressure of the system rather than being told about it. That is an aesthetic effect produced by design, and it is available to no other art form.

The other side of that coin is authorship. A game is made by teams of dozens or hundreds of people, and no single person can be credited with the whole in the way that a novelist or a painter can. Yet the same could be said of a cathedral, a film or an opera, and nobody concludes that these are not art. What matters is whether the result was shaped deliberately by someone with something to express; in games the shaping is done through systems and rules, and the intention can be read in them by anyone who plays attentively.

Institutions have already begun to treat games in this light. In 2012 the Museum of Modern Art in New York acquired fourteen games for its collection of design, and the Smithsonian American Art Museum mounted an exhibition on the history of the medium in the same year. None of these decisions settles the philosophical question; a museum can collect anything it likes. But they change how games are kept, catalogued and discussed.

Here the argument about the word 'art' becomes practical. What the label usually secures is not admiration but infrastructure: funding, conservation, scholarship and criticism. A medium whose best works are not preserved cannot be studied, and games are unusually vulnerable to loss. Servers are switched off, formats become unreadable and hardware wears out, so that games barely two decades old are already difficult to play. Yet the label can also mislead. It tempts us to sort games into an artistic elite and dismiss the rest as mere entertainment, which is where most of the medium's invention has always happened.

The deeper difficulty is that nobody agrees what art is. The word has no agreed definition, and attempts to supply one have usually ended by excluding something that later generations admired. Since the early twentieth century, philosophers have largely accepted that a work becomes art partly because institutions and audiences treat it as such, which makes the question circular. That is not a satisfying answer, but it may be closer to the truth than any list of essential properties.

My own view is that games belong to the arts without being especially noble for it. The medium has produced work of genuine beauty and, at its best, a kind of involvement that films and novels cannot offer. But the question 'are games art?' has never been the important one. The useful questions are which games deserve to survive, what they are saying, and who is equipped to explain them, and those can be answered without settling a definition. The medium is young; it has existed for well under a century, and the work it will be judged by may not yet have been made.