New-Age Transport
It looks as if it came straight from the set of Star Wars. It has four-wheel drive and rises above rocky surfaces. It lowers and raises its nose when going up and down hills.And when it comes to a river, it turns amphibious: two hydrojet power it along by blasting water under its body. There is room for two passengers and a driver, who sit inside a glass bubble operating electronic, aircraft-type controls.A、vehicle so daring on land and water needs windscreen wipers--but it doesn’t have any. Water molecules are disintegrated on the screen’s surface by ultrasonic sensors.
This unusual vehicle is the Racoon. It is an invention not of Hollywood but of Renault, a rather conservative French state-owned car-maker, better known for its family hatchbacks. Renault built the Racoon to explore new freedoms for designers and engineers created by advances in materials and manufacturing processes. Renault is thinking about startlingly different cars; other producers have radical new ideas for trains, boats and aeroplanes.
The first of the new freedoms is in design. Powerful computer-aided designCAD、systems can replace with a click of a computer mouse hours of laborious work done on thousands of drawing boards. So new products, no matter how complicated, can be developed much faster. For the first time,Boeing will not have to build a giant replica of its new airliner, the 777, to make sure all the bits fit together. ItsCA
D、system will take care of that.
But Renault is takingCA
D、further. It claims the Racoon is the world’s first vehicle to be designed within the digitised world of virtual reality.Complex programs were used to simulate the vehicle and the terrain that it was expected to cross. This allowed a team led by Patrick G. M. Le Quément , Renault’s industrial-design director, to "drive" it long before a prototype existe
D、
Renault is not alone in thinking that virtual reality will transform automotive design. InDetroit, Ford is also investigating its potential. Jack Turner, the firm’s head of design, would like designers in different parts of the world to work more closely together, linked by computers. They would do more than style cars. Virtual reality will allow engineers to peer inside the working part of a vehicle.Designers will watch beatings move, oil flow, gears mesh and hydraulics pump.As these techniques catch on, even stranger vehicles are likely to come along.
Transforming these creations from virtual reality to actual reality will also become easier, especially with advances in materials. Firms that once bashed everything out of steel now find that new alloys or composite materials (which can be made from mixtures of plastic, resin, ceramics and metals, reinforced with fibres such as glass or carbon) are changing the rules of manufacturing.At the same time, old materials keep getting better, as their producers try to secure their place in the factory of the future.
This competition is increasing the pace of development of all materials.
One company in this field is ScaledComposites.
It was started in 1982 byBurr Rutan, an aviator who has devised many unusual aircraft.
It has also worked on composite sails for theAmerica’sCup yacht race and on General Motors’ Ultralite, a 100-miles per-gallon experimental family car built from carbon fibre.
Again, the Racoon reflects this race between the old and the new. It uses conventional steel and what Renault describes as a new "high-limit elastic steel" in its chassis. This steel is 30% lighter than the usual kin
D、The Racoon also has parts made from c

Innovations in MedievalEuropeanAgriculture
1. In the year 1,000CE,Europe’s societies were organized under a system known as Manorialism. The basic unit was the manor, a village or villages including large areas of farmland and ruled over by a lord, who provided military protection for the local peasant population in return for their labor and a share of their harvested crops. Unfortunately, the agricultural techniques in practice at the time were rather undevelopeD、Farmers had to work arduously every day to produce just enough food to survive.But then, in the eleventh century, several changes took place that allowed for a significant increase in crop yields.
2. Several factors may have played a role in this transformation. There is evidence, for example, that the global climate began to warm slightly in the ninth century.
Historians also note that the frequency of violent invasions by neighboring peoples had decreased by the year 1,000.
Yet, even more important were several specific technological innovations, some of which were introduced from other parts of the world,
European farmers had, to some extent, already been influenced by outsiders; the waterwheels and windmills used during Manorialism originated in the Muslim world, for instance.
It was the tools and techniques that made their way onto the continent after 1,000CE, however, that drastically changed the course ofEuropean agriculture.
3. Prior to the eleventh century, most farmers practiced the old Roman two-field system of crop rotation.A、plot of land would be divided into two halves. The two halves were then rotated every six months, with one being planted and the other going unuseD、This system worked in the Mediterranean region, where soil quality was generally lower. However, first in Germany, then elsewhere inEurope, farmers finally figured out that the local conditions could support more crops, and they began to implement a three-field system.Each parcel of land was now divided into thirds, with two growing crops and one lying fallow at any given time.This simple modification yielded 33% more food while requiring less labor and also encouraged the planting of a greater variety of crops.As diets improved and peasants acquired more free time, they were able to undertake the clearing of land by cutting trees and draining marshes, thus creating more farmland and further increasing food production.
4.Another shift toward greater agricultural efficiency came as the result of a new tool. Up until this time, most peasants used a simple wooden plow to cut furrows in the fields. Likely introduced by the Slavs ofEasternEurope, the heavy plow made this job much easier. It featured a large iron blade to slice through the thick soil and other features that reduced the amount of time it took to dig adequate furrows.Due to its weight, a team of eight oxen was needed to pull the heavy plow, and, because most peasants were lucky to own one ox, their new tool led to greater collaboration among farmers. Single-family fields were combined to create large communal plots, and cooperation boosted efficiency.Another change was that, since a team of eight oxen was very difficult to turn, long vertical strips of farmland took the place of the standard square fielD、
5.As time went on, the use of oxen in plow teams was abandoned in favor of the horse. This resulted from both the invention of the horseshoe around 900CE, which enabled horses to work without damaging their hooves, and the introduction of the horse collar, giving the animals the ability to pu

Iodine and Goiter
Iodine is a well-known example of a trace mineral whose lack in the body creates an easily treated disease. When the thyroid gland is not supplied with sufficient iodine to manufacture hormones, it enlarges and forms a goiter or swelling of the neck.At the same time other symptoms, such as fatigue and sluggishness, weight gain, coldness of the body, and depression, may occur.
In the United States goiter was first noted in the Great Lakes region, where in the 1930s, as many as 40 percent of the people in some areas had goiter, due mainly to iodine-deficient soil. This scarcity had been caused by ice age glaciers melting and washing the iodine out of the soil.
The inhabitants of mountainous regions ofEurope had suffered from iodine deficiency for centuries for similar reasons.
It was discovered in the alpine region of Switzerland in the nineteenth century that in areas in which the drinking water contained less than 0.5 micrograms of iodine per liter there was a high incidence of goiter.
In contrast to mountainous or inland regions, areas by oceans or in the vicinity of ocean breezes usually contain enough iodine to prevent this affliction.
As a fairly accurate rule of thumb, if a map is drawn showing the parts of the world where the water supply is deficient in iodine and then superimposed on a map showing the areas where the inhabitants suffer from goiter, the two mapped areas coincide.
To understand how iodine deficiency leads to goiter, it is necessary to look at the underlying physiology of the thyroid glanD、The human thyroid gland is the only place in the body where iodine is stored, and it requires a daily supply of about 150 micrograms of iodine entering the body. When food or water is digested, the iodine it contains is either taken up by the thyroid or eliminated from the body through the kidneys into the urine. When supplies are low, the kidneys still eliminate iodine from the body so the capacity of the thyroid to preserve an adequate supply of raw material is threateneD、
The thyroid gland consists of thousands of balls of cells, called thyroid vesicles, which enclose a space filled with a jellylike protein called thyroglobulin. These cells have an extraordinary ability to trap iodine from the bloodstream, and the efficiency of this trap can be increased if the amount of iodine in the blood circulation decreases. Once the iodine is trapped by the thyroid vesicles it passes into the thyroglobulin, where the actual manufacture of two kinds of thyroid hormones takes place. The hormones are stored here until they travel back through the thyroid vesicles to enter the bloodstream. The thyroid hormones are then taken to every part of the body where they influence the rate at which the chemical processes of every cell proceeD、They have a pervasive effect on the control of oxygen consumption and heat production of the whole body, and they are essential to the healthy growth of body and minD、
The thyroid tries to keep constant the amount of circulating thyroid hormone entering the cells of the body. When iodine supplies are low, the pituitary gland, a small pea-sized gland at the base of the brain, secretes a thyroid-stimulating hormone (TSH) that in turn regulates the power of the thyroid to trap iodine and increase the output of the thyroiD、If the thyroid is continually stimulated by TSH, the cells get larger and eventually the whole gland enlarges with an increase in the number of its cells. The thyroid may have many temporary crises where iodine supplies are not adequate and where swelling in induced unde

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