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possible dangerous effects of improper recycling methods on pollution levels and people’s health;

harmful effects of modern personal computers; safety check results of some recycling centers;

measures that should be taken to solve the problem of hightech waste disposal.

Are Recycled PCs Harming the Earth?

For years, environmentalists and responsible PC makers have encouraged computer users to recycle their old computers instead of simply throwing them out. Millions of environmentally loyal consumers and businesses have heeded the call. Instead of tossing their old PCs and other hardware into a dumpster, these users have donated them to charitable or given them to recycling centers.

In the United States today, there are thousands of individual computer recycling centers in operation. Many of them keep the old computers in house, stripping away parts that can be used, then safely recycling the unusable parts.

More often, however, recyclers ship the old hardware overseas, and millions of tons end up in China, India, and developing nations. There, often in impoverished villages with little or no other industry, workers dismantle old PCs by hand, exposing themselves to harmful chemicals and releasing thousands of pollutants into the air, water, and the ground.

Now, environmentalists have issued a new plea: that responsible governments and industries work together to stop this practice. If it continues unabated, experts argue, we can expect thousands of recycling workers to become ill, and for pollution levels to rise to unprecedented levels in areas where improper recycling methods are used.

Understanding the problem

Despite their increasing user-friendliness, computers are anything but friendly to the environment. Today’s computers contain any number of agents that can be harmful to the environment, if not processed correctly. The average cathode ray tube (CRT) monitor, for example, contains several pounds of lead, which is a known poison. Further, CRTs can explode if not handled properly, scattering glass fragments and other materials.

Laptop computers offer their own threats to the environment. The vast

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majority of portable systems use batteries that contain poisonous heavy metals, such as cadmium. If not disposed of properly, these batteries can become damaged into the environment. A computer’s wires and circuit boards are still another issue. When burned, these components can create toxic fumes. When simply tossed into a landfill, they will last virtually forever.

These problems are compounded by the fact that millions of obsolete PCs are discarded every year. Only a small fraction of these systems are properly recycled in the United States, because the process is expensive and yields a relatively small amount of reusable components or materials. Recyclers have found it cheaper and easier simply to ship the old PCs to other countries, which take charge of “processing” the hardware and reclaiming usable materials.

In recent months, environmentalists from developed nations have visited these recycling centers and been alarmed by the conditions they found. Overseas recyclers, however, generally do not follow standard practices for recycling, placing workers, communities, and the environment at risk. In some cases, workers strip old computers with their bare hands and minimal tools; around them, fires burn discarded plastic and silicon and fill the air with a constant haze of toxic fumes and ash. Little care is taken to protect local water supplies or food sources from toxins.

Finding solutions

In the past few months, several European countries and Japan passed laws declaring waste (such as old computer hardware) cannot be exported. This forces recyclers to handle cast-off computers properly instead of dumping them somewhere else.

At a global level, the United Nation’s Environmental Program has overseen the Basel Convention for several years. This international group studies the problem of global environmental hazards and develops treaties; member nations pledge to follow strict guidelines for dealing with various kinds of waste. The Basel Convention is working on strengthening its coverage of “e-waste”, or pollution stemming from technology components. In the United States, a task force of lawmakers and computer-industry experts is working on legislation governing the disposal of high-tech waste. There is no timetable for passing that legislation, however. Traditionally, American computer makers have

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opposed such legislation, but have since joined in the push for reform. Despite their willingness to help, however, the issue of recycling forces manufacturers to face a new problem. That is, who will pay for recycling? One idea is for computer makers to build a recycling fee into the price of new computers. Then, at the end of a computer’s life, the user could return it to the manufacturer or to an approved PC recycler, with the recycling fee already paid up-front.

PC makers worry about a consumer backlash against such a fee, and environmentalists worry that despite paying such a fee, many consumers will simply toss their old PCs into the trash without attempting to recycle them. No matter what solution develops, consumers will have to bear at least a portion of the cost.

(http://www.interconrecycling.com/recycled_pc.htm)

2.2.In the paragraphs you have marked in task 2.1 underline the key words and key phrases that express the main points of the paragraphs.

2.3.Summarize the main points of the whole article using the phrases below:

The article suggests the problem of … . The effects of … on … are considered. The article covers such points as … .

It is claimed that … . Attention is given to … .

Attention is also concentrated on … .

Text 3

3.1.Read the title and the subtitle of the article and discuss what you already know about nanotube circuits. Read the article to learn more about this technology.

Nanotube Circuits

Carbon nanotubes combine high performance and flexibility for electronics

(1) New research suggests that networks of single-walled carbon nanotubes printed onto bendable plastic perform well as semiconductors in integrated circuits. Researchers from the University of Illinois at

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Urbana-Champaign (UIUC) and Purdue University say that these nanotube networks could replace organic semiconductors in applications such as flexible displays.

(2)Development of flexibe electronics has recently focused on organic molecules because, unlike silicon, they are compatible with bendable plastic substrates. Flexible electronics have potential in such applications as lowpower electronic newspapers or PDAs that roll up into the size and shape of a pen. The problem with existing organic-electronic devices, however, is that “they aren’t well developed for long-term reliability, and they perform far worse than silicon,” says John A. Rogers, an engineering professor at UIUC.

(3)Carbon-nanotube networks, on the other hand, combine the performance of silicon with the flexibility of organic films on plastic. Rogers says that the speed of the nanotube device compares favorably with the speed of commercially used single-crystal silicon circuits. The transistors can also switch between on and off states in the range of several kilohertz, which is similar to the range of those used for liquid crystal displays and radio frequency identification (RFID) sensors. However, the on-off current ratio for carbon nanotubes is still a few orders of magnitude lower than that for silicon transistors.

(4)The researchers made the networks by depositing nanotubes onto plastic by standard printing methods, which could lead to low-cost, largescale fabrication. And the printed circuits can bend to a radius of about five millimeters without compromising the electrical performance of the device. “This method is good for flexible electronics that need to be printed over a large area,” says Ali Javey, an assistant professor of electrical engineering at the University of California, Berkeley.

(5)Using a technique called transfer printing, the researchers deposited randomly aligned carbon nanotubes onto a 50-micrometer-thick sheet of plastic, and then patterned gold electrodes and other circuit components onto the substrate. Because about one-third of the nanotubes in any network are metallic, the researchers then etched narrow parallel lines through the network with soft lithography. By cutting the nanotubes, they can effectively eliminate the possibility of a purely metallic pathway connecting two electrodes while preserving the performance of the device.

(6)Several challenges still remain before the nanotubes networks are

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ready for actual products. Devices need to be made in which the performance from device to device doesn’t vary; billions of individual nanotubes have to be made with high purity and the right dimensions for optimal performance. The printing process also needs development, says George Gruner, a professor of physics at the University of California, Los Angeles. Gruner suggests that nanotubes could be dissolved into ink and then printed onto plastic. “These devices have to be cheap and disposable,” especially for devices like RFID tags in food packaging, he adds. Rogers’s group’s immediate goals are to work toward lower power and higher speed in the devices. “We want to push the limits to see how far we can go,” he says.

(Lauren Rugani, http://www.technologyreview.com/computing/21119, July 2010)

3.2.Read paragraph 1 and condense it using the phrases below:

The article deals with the problem of … The purpose of the research is to …

3.3.Read paragraphs 2 and 3 that describe the advantages of nanotube networks. Present the content of these paragraphs using the phrases:

A detailed description is given to …. It is shown that … .

It is reported that … .

3.4.Read paragraphs 4 and 5 that describe the main techniques for producing nanotube networks. Compress these paragraphs into statements using the phrases:

It is found that … .

It is said/ recognized that… . The fact that … is stressed.

3.5.Read paragraph 6 and name some challenges that still remain unsolved. Present the content of this paragraph using the phrases:

It is believed that… .

The research has given rise to …

3.6.Summarize the content of the whole article.

Text 4

4.1.Read the title of the article and make predictions on its content. Check your predictions.

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USB Flash Drives Revolutionize Portable Storage but Pose Security Risks for Organizations

Over the last few years USB Flash Drives have become a must-have item for computer users everywhere. We rely on them to transport all kinds of data including letters, spreadsheets, presentations, music and even movies. The capacity, physical size and speed of these drives has increased rapidly, and with that prices have come down making them an affordable accessory rather than luxury item. They have now completely replaced the humble Floppy Disk as the dominant format for re-writeable, portable storage, and rightfully so – Floppy Disks were well past their sell-by date at the turn of the 21st century.

But there are some risks associated with such a small device capable of storing vast amounts of data being kept in the pockets and on the key chains of millions of workers at companies/organizations across the world. Let’s take a look at some of these risks in detail.

The first risk is a loss of productivity; workers could use their USB Flash Drives to bring in software that is not suitable for the workplace, such as games or “joke” applications that could cause disruption. Employees could also use the fast internet access usually provided in the corporate network to download illegal or unsavoury material onto their USB Flash Drives that could damage the company’s reputation and potentially cause spyware or adware infections. The second risk is of workers bringing viruses, trojans, malware or adware into the workplace on USB Flash Drives. An example of this would be an employee with poor security on their home computer bringing a file he/she has been working on at home into the workplace on their USB Flash Drive and plugging it into a company machine. This could expose the corporate network to all kinds of viruses or malicious code that may have been transferred on the USB Flash Drive from an unprotected computer. The third and most serious risk is the theft of confidential data or

“data leakage” as it has come to be known. There have been many cases in the past where workers are given access to confidential information and abuse their position by copying sensitive data onto a USB Flash Drive. If this data is later leaked, it could cause embarrassment to the company involved with the possibility of negative press coverage, and they may even be subject to legal action. There is also the possibility of a USB Flash Drive containing confidential information being lost or misplaced by accident. A worst case scenario would be a USB Flash Drive dropping out of the pocket of a worker

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when out on their lunch break; this could mean a database with thousands of records of private information falling into the hands of unscrupulous people. There is now a solution to the problem of data leakage – a USB Flash Drive with strong 256-bit AES hardware-based. The SanDisk Cruzer Enterprise, available from Lucid IT Security, is the answer IT professionals needing to protect information on company-issued USB flash drives have been looking for. It is specifically designed to meet the unique USB security, compliance and manageability needs of enterprises. Rather than rely upon users to secure files, it imposes mandatory access control on all files, storing them in a hardware-encrypted, password-protected partition. The Cruzer Enterprise is also the first secure USB flash drive to fully support Apple Mac OS X computers, and can be initialized from either a Macintosh or a Windows computer. By supporting both Macintosh and Microsoft Windows environments, IT professionals can more effectively use SanDisk Cruzer Enterprise to protect information on company-issued secure USB flash drives across their organizations. Server-side software is also available to manage the Cruzer Enterprise drives-SanDisk CMC (Central Management and Control) adds a higher level of control to Cruzer Enterprise. It centrally manages the drive’s complete lifecycle, from initial userdeployment, through password administration and data backup, and finally to drive termination if lost or stolen.

(Alex Culshaw, http://www.articlesphere.com, January, 2009)

4.2.Indicate the paragraph that explains the advantages of USB Flash Drives and their popularity with computer users. Read this paragraph and define its main point. Summarize the paragraph in no more than two sentences. Begin with:

The article informs…

The article discusses/analyzes …. The article raises up a question of…

4.3.Indicate the paragraphs that describe some of the risks associated with such small devices. Read them again and condense their content into 4 statements using the phrases:

The article also considers … . Attention is given to … .

The article touches upon … . . Particular emphasis is placed on … .

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4.4.Indicate the paragraphs where the solution to the problem of data leakage is suggested. Read these paragraphs and compress their content into statements using the phrases:

A solution to the problem of … is proposed. Special emphasis is placed on…

The article is of particular interest beсause… .

The article is of little professional interest, because… .

4.5.Summarize the content of the article.

Text 5

5.1.Read the title and the subtitle of the article and think what exactly it is going to be about. Check your guesses.

How to Really Trust a Mathematical Proof

Mathematicians develop computer proof-checking systems in order to realize century-old dreams of fully precise, accurate mathematics

The one source of truth is mathematics. Every statement is a pure logical deduction from foundational axioms, resulting in absolute certainty. Since

Andrew Wiles proved Fermat’s Last Theorem, you’d be safe betting your life on it.

Well … in theory. The reality, though, is that mathematicians make mistakes. And as mathematics has advanced, some proofs have gotten immensely long and complex, often drawing on expertise from far-flung areas of math. Errors can easily creep in. Furthermore, some proofs now rely on computer code, and it’s hard to be certain that no bug lurks within, messing up the result.

Bet your life on Wiles’ proof of Fermat? Many mathematicians might decline.

Still, the notion that mathematical statements can be deduced from axioms isn’t nonsense. It’s just that mathematicians don’t spell out every little step. There’s a reason for that: When Bertrand Russell and Alfred North Whitehead tried to do so for just the most elementary parts of mathematics, they produced a 2,500-page tome. The result was so difficult to understand that Russell admitted to a friend, “I imagine no human being will ever read through it.”

Where humans falter, computers can sometimes prevail. A group of

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mathematicians and computer scientists believe that with new proofvalidation programs, the dream of a fully spelled-out, rigorous mathematics, with every deduction explicit and correct, can be realized.

Indeed, Freek Wiedijk of Radboud University Nijmegen in the Netherlands says a revolution is already occurring. He writes in the December Notices of the American Mathematical Society that in the future,

“most mathematicians will not consider mathematics to be definitive unless it has been fully formalized”.

The first proof-validation programs were created more than 20 years ago. Until recently, though, they were so cumbersome that the only users were the researchers who had created and were trying to improve them. Furthermore, even those researchers were only tackling relatively simple theorems. In the last five years, though, those users have finally been able to verify some remarkably complex and difficult proofs. Before long, they say, ordinary mathematicians will be using these tools as part of their everyday work.

Perhaps the most remarkable success so far came in 2004, when Georges Gonthier, a computer scientist at Microsoft Research in Cambridge, England, verified the proof of the four-color theorem by computer. The problem dates back to 1852, when a college student noticed that only four colors were needed to fill in a map of the counties in England such that no adjacent counties shared a color. It took until 1976 to mathematically prove that four colors were enough for any map. That proof was more than 500 pages long and relied on computers to check nearly 2,000 special cases. Many mathematicians objected to the proof because it was impossible to check by hand.

Gonthier used a proof-checking software package to formalize the entire proof, reducing both the text and the software for the special cases to an enormously long series of simple deductions.

Of course, if the proof-checking software itself has bugs, Gonthier’s verification of the four-color theorem itself could be invalid. To guard against this possibility, the designers of the proof-checking software make the “kernel” of code that implements the axioms and rules of inference as short and simple as possible. One program, HOL Light, has fewer than 500 lines of code in its kernel, few enough that humans can check it by hand. John Harrison, the creator of HOL Light, has also checked the code using other formal proof-checkers!

The software may not be able to produce perfect certainty, but

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Thomas Hales, a mathematician at the University of Pittsburgh, calls the four-color theorem “one of the most meticulously verified proofs in history.”

Hales is one of the first working mathematicians to embrace the proofcheckers, because he ran up against the limits of mathematical certainty himself. He proved the Kepler Conjecture in 1998, which is another theorem that is simple to state but remarkably hard to prove. The Kepler Conjecture says that the pattern grocers use to stack oranges packs the most oranges into the smallest space. As with the four-color theorem, Hales used a computer to check many, many special cases, and the proof consisted of 300 pages of text and 40,000 lines of computer code.

When he submitted his result for publication, he received only a qualified acceptance. The letter from the editor explained that “the referees put a level of energy into this that is, in my experience, unprecedented.” Nevertheless, the referees ended up only 99 percent certain that the proof was correct. The referees were unable to check the computer code at all.

Hales decided that 99 percent certainty wasn’t good enough for him. He started the “Flyspeck” project (named from the acronym FPK, for

Formal Proof of the Kepler Conjecture) to formalize his entire proof. When he began, he estimated that it would take 20 person-years to complete it (i.e., one person working for 20 years, for example, or 10 people working for two years). He says now that he is about halfway through, and his team has indeed devoted about 10 person-years.

Hales and Gonthier are managing to do more than simply check those particular proofs. In the process, they are creating a library of basic formalized results other mathematicians can use to formalize new proofs. Since new proofs always rely on many, many previous proofs, this library provides the essential foundation mathematicians need to efficiently use the proofverification software programs in their daily work.

Once that library is created, widespread use may not be so far off. Gonthier has been surprised to find that with experience, coding a proof takes little more effort than typesetting an ordinary mathematics article, which mathematicians do regularly. “The actual coding of results seems to go on pretty quickly,” Gonthier says.

The hard part is the early stages, he says, teaching the computer what an early graduate student would know. Mathematicians use many, many

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