Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.

Error 404--Not Found

Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.

Top 15 Technologies
4. Fuel cells

Daimler-Benz (DB) has moved fuel cell technology nearer to production reality with an on-board system for generating hydrogen from methanol. The company, now working with the Canadian company Ballard Power Systems, claimed the system as a "world first" when it gave details at the Frankfurt Motor Show. DB calls the research vehicle NECAR (New Electric Car) 3. It is based on Mercedes-Benz's latest model, the A-class. A reformer is carried that converts the methanol into hydrogen by water vapor reformation. The hydrogen gas is fed to fuel cells to react with atmospheric oxygen which in turn produces electrical energy to power the car. The great attraction of methanol is that it can easily fit into the existing gasoline/diesel infrastructure of filling stations and does not need highly specialized equipment or handling. It is also easy to store on board the vehicle, unlike hydrogen, which needs heavy and costly tanks. DB says NECAR3 has a range of about 400 km on a 40 liter methanol tank; it has decided methanol is a more efficient fuel for hydrogen generation than either gasoline or diesel, both of which are being researched by other manufacturers and suppliers. However, consideration is, initially at least, being given by DB to multi-fuel hydrogen sourcing.

Detailing the research car, DB says the methanol reformer technology used has benefited from developments that have allowed the system to become smaller and more efficient compared to earlier efforts. But performance and dynamic response have been improved. The result is a compact, 47-cm-high unit. Located in the rear of the A-class, the reformer directly injects hydrogen "on-line" into the fuel cells. Hydrogen production occurs at a temperature of some 280 C. Methanol and water vaporize to yield hydrogen (H), carbon dioxide (CO2), and carbon monoxide (CO). Following catalytic oxidation of the CO, the purified gas is fed to the negative pole of the fuel cell. A special plastic foil, which is coated with a platinum catalyst and sandwiched between two electrodes, is located at this position. The conversion of the hydrogen into positively charged protons and negatively charged electrons begins with the arrival of oxygen at the positive pole. Since the foil is only permeable to protons, an electrical voltage, which can be used to drive the electric motor, builds up across the fuel cell.

By Stuart Birch

Error 404--Not Found

Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.