Nickel wheel

Molecular structure of the nickel wheel. The bridging pyridone and terminal THF ligands point alternately above and below the mean plane of the twelve nickel atoms. From A. J. Blake, C. M. Grant, S. Parsons, J. M. Rawson and R. E. P. Winpenny. Chem. Commun., 2363—4 (1994). 

Manganese is presently absent from this family. Our attempts to make an Mn wheel similar to the cobalt and nickel wheels led to a one-dimensional polymer [Mn2(chp)2(02CMe)2(Me0H)2] [52]. There is in this structure curvature within each trinuclear unit, however, in neighbouring units the structure curves in opposite directions, leading to a zigzag polymer rather than a wheel. There must be a fine balance between these two alternative structures. 

The greatest use of cubic boron nitride is as an abrasive under the name Bora2on, in the form of small crystals, 1—500 p.m in si2e. Usually these crystals are incorporated in abrasive wheels and used to grind hard ferrous and nickel-based alloys, ranging from high speed steel tools and chilled cast-iron to gas turbine parts. The extreme hardness of the crystals and their resistance to attack by air and hot metal make the wheels very durable, and close tolerances can be maintained on the workpieces. 

The bulk of synthetic industrial diamond production consists of the smaller crystal sizes up to 0.7-mm particle size (25 mesh). This size range has wide utihty in industry, and a significant fraction of the world s need for diamond abrasive grit is now met by synthetic production yielding thousands of kilograms per year. Because the raw materials are plentiful, synthetic production could, if necessary, supply the world demand for diamond abrasive. Development work continues in order to improve size and utility of the manufactured product and to realize the full potential of diamonds at minimum cost. An appreciable increase in performance has been obtained by coating the diamonds with a thin layer of nickel or copper, before incorporating them into wheels. The thin layer of metal apparendy improves adhesion and heat transfer. 

The Peugeot Quark ATV uses an air-cooled fuel cell with a 40 cell nickel metal hydride battery. The 9 liter hydrogen tank can be pressurized to 10,150 psi for a range of up to 80 miles. The tank is designed to be exchanged for a full one when empty. Each 17 inch wheel has its own electric motor that can produce 74 pound-feet of torque. The motors also supply regenerative braking. 

In 1994 and 1995, H-Power (Belleville, New Jersey) headed a team that built three PAFC/battery hybrid transit buses (24,25). These 9 meter (30 foot), 25 seat (with space for two wheel chairs) buses used a 50 kW fuel cell and a 100 kW, 180 amp-hour nickel cadmium battery. 

Copper electrorefining plays a major role in the production and recycling of copper. In the production of copper, copper-bearing sulfide concentrates are first smelted to copper matte. The molten matte is oxidized to blister copper by a Peirce-Smith converter and the blister copper is fire refined and cast to copper anodes. Blister copper contains about 99% copper and impurities such as arsenic, bismuth, iron, nickel, lead, antimony, selenium, tellurium, and precious metals. It is cast into flat anodes, most often on a rotating horizontal wheel. The mold shape includes lugs by which the anodes are... 

There is a large group of polynuclear cages of 3d-metals in moderate oxidation states which do not fit within the above classifications. These are the metal wheels . There are rings known for the metals fi-om titanium to nickel (with the exception of manganese), and with nuclearities varying from 8 to 12. This is in itself another family of structures. 

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