the nature of technology brian arthur pdf

... to show the relative positions and movements of the sun, planets, and moon as they cir- cled the earth. As the center of the uni- verse, the earth was a sphere in the center of the orrery. The other ... of the last two centuries has been the discovery of the vast expanse of geologic time. Early methods of calculating the age of the earth relied on measures of the rate of sedimenta- tion or the ... movements of the planets given the laws of motion that Newton derived. As a result of the steady accumu- lation of evidence, the theological interpre- tation of celestial movements gave way to the...

Ngày tải lên: 27/06/2014, 18:20

... copper. Smelting of oxide and carbonate copper ores It seems that towards the end of the fourth millennium BC, the supplies of native copper accessible to the ancient world were incapable of satisfying ... well below their melting point to soften them after cold forging, or in the furnaces where crystals were melted together. Apart from gold, silver and the other noble metals, copper is the only ... think for themselves. This is a concept that to many people appears ridiculous and to many others a threat to the dignity of themselves as members of the human race or worse, a threat to the very existence...

Ngày tải lên: 04/07/2014, 01:20

... Salindres to reduce the melting point and viscosity of the slag, and to dissolve the thin layers of alumina which formed on the surface of the reduced globules of aluminium, thus enabling them to coalesce. ... furnace. The furnace charge consisted of 100kg (220lb) of the double chloride, 45kg (99lb) of cryolite and 35kg (77lb) of sodium. The function of the cryolite was to act as a flux and dissolve the ... a very high thermal conductivity. This encouraged its use for cooking utensils. The first authenticated use of aluminium as a roofing material is provided by the dome of the Church of San Gioacchino...

Ngày tải lên: 04/07/2014, 01:20

... one above the other to prevent loss of gas. The top bell is opened and the raw materials fall on the lower one, which is closed and sealing the furnace. Then the top bell is closed and the bottom ... production. The wrought iron balls as they came from the furnace were always hammered out into a bloom, but the next stage depended on the grade of iron being made. Figure 2.2: The product of the puddling ... When the pig iron was brought up to melting point, some of it formed magnetic oxide (Fe 3 O 4 ) which made slag with the silica in the sand lining of the furnace. This was the source of the waste;...

Ngày tải lên: 04/07/2014, 01:20

... diameter the operator tried the gauge which should pass the ‘Go’ anvil but not pass the ‘No Go’ end. The difference in the anvil dimensions is the tolerance allowed on the dimension to which the part ... dimensional standards for the whole world by 1926 and he is referred to as the ‘Master of Measurement’. The use of gap gauges also became common for the inspection of screw threads based on the idea of William ... these industries. With the coming of the motor industry this firm grew to become one of the most famous machine tool manufacturers in the world, Alfred Herbert Ltd. Frederick Lanchester was the...

Ngày tải lên: 04/07/2014, 01:20

... protection against the weather for the rider. The design of the moped originated in the folding scooters such as the Corgi used by paratroops during the war. Another development of the same period, ... to the diamond- shaped frame of the ‘safety’ pedal bicycle. Coventry was again the centre of the industry which really took off with the repeal of the ‘Red Flag’ Act in 1896, a maximum speed of ... for some years, was the bubble-car. Heinkel and Messerschmitt were both prominent makes of these machines, the designs of which owed much to the cockpits of the aircraft which these companies had...

Ngày tải lên: 04/07/2014, 01:20

... and their size increased. It was further improved in the 1880s but the construction in the 1950s of the St Lambert and Côte Ste Catherine locks on the St Lawrence Seaway spelled the end of the ... In the south also at the beginning of the eighteenth century, a start was made on linking the Volga and the Don so that traffic could go to either the Black Sea or the Caspian Sea. At the end of ... from the upper level above the power station on to the crest of the dam and a second plane lowering the boats into the tail water PART THREE: TRANSPORT 506 when the vital importance of the canal...

Ngày tải lên: 04/07/2014, 01:20

Ngày tải lên: 04/07/2014, 01:20

Ngày tải lên: 04/07/2014, 01:20

Ngày tải lên: 04/07/2014, 01:20

Ngày tải lên: 04/07/2014, 01:20

Ngày tải lên: 04/07/2014, 01:20

Ngày tải lên: 04/07/2014, 01:20

Ngày tải lên: 04/07/2014, 01:20

... divined in the cellar of the City branch of one of the principal London banks. Mr. Merryweather is the chairman of directors, and he will explain to you that there are reasons why the more daring ... "it was perfectly obvious from the first that the only possible object of this rather fantastic business of the advertisement of the League, and the copying of the Encyclopaedia, must be to ... rogue has the temporary office, the other rogue incites the man to apply for it. and together they manage to secure his absence every morning in the week. From the time that I heard of the assistant...

Ngày tải lên: 15/12/2013, 14:15

... how we broke the sad news to the terrified girl, how we conveyed her by the morning train to the care of her good aunt at Harrow, of how the slow process of official inquiry came to the conclusion ... data. The presence of the gypsies, and the use of the word 'band,' which was used by the poor girl, no doubt to explain the appearance which she had caught a hurried glimpse of by the ... laid it on the corner of the table. Holmes had brought up a long thin cane, and this he placed upon the bed beside him. By it he laid the box of matches and the stump of a candle. Then he...

Ngày tải lên: 24/12/2013, 20:15

... from the very heads of your profession. Still, of course, if you would like to draw out of the business, there is plenty of time to do so.' "I thought of the fifty guineas, and of ... during the years of our intimacy, there were only two which I was the means of introducing to his notice that of Mr. Hatherley's thumb, and that of Colonel Warburton's madness. Of these ... cold, dank grasp, he hurried from the room. THE ADVENTURES OF SHERLOCK HOMES ARTHUR CONAN DOYLE The Adventure of the Engineer's Thumb Of all the problems which have been submitted...

Ngày tải lên: 22/01/2014, 01:20

... mouth. It was the clank of the levers and the swish of the leaking cylinder. He had set the engine at work. The lamp still stood upon the floor where I had placed it when examining the trough. ... into the darkness. "I glanced at the books upon the table, and in spite of my ignorance of German I could see that two of them were treatises on science, the others being volumes of poetry. ... on. The ceiling of this small chamber is really the end of the descending piston, and it comes down with the force of many tons upon this metal floor. There are small lateral columns of water...

Ngày tải lên: 22/01/2014, 01:20

... of the by the Statistical Office of Finland showed that 30% of the elderly women used washing machines, whereas 7% of men used these electrical devices 14 . According to the results of the ... devices were in perfect line with the level of perception of the elderly. From the results of the present study, it is evident that the use of new technologies by the elderly population significantly ... ignored the services and opportunities provided by the machines of this type. On the contrary, 5.9% of participants reported that they were aware of all the services and capabilities of ATMs. The...

Ngày tải lên: 28/03/2014, 19:21

... by 0.0167 gặcm )3 , from the start of the experiment. By the end of the measurement, the thickness had increased by 0.342 nm, the mass had increased by 0.10 ngặmm )2 and the density had decreased ... fluores- cence. The subsequent plateau phase is associated with a decrease in the concentration of small species, or the aggregation and precipitation of fibrils [37]. The kinet- ics of these three stages of ... min. In the main, the pres- ence of a-crystallin significantly decreased formation of this large aggregate. As a result of the interaction of a-crystallin with reduced j-casein, a complex of similar mass...

Ngày tải lên: 30/03/2014, 04:20