Elevator designers are constrained by the
weight and strength of steel cables to shafts no higher than 600 meters, with large
equipment rooms to contain the massive motor and gearworks. Schindler Management Ltd,
Ebikon, Switzerland, has introduced into the European market the first fully synthetic
elevator ropes, manufactured from aramid. SchindlerAramid ropes provide the same breaking
strength as steel ropes but with much lower weight, and they also have a high coefficient
of friction and high reverse-bending strength. As a result, for a given rated load, much
smaller drive machines can be used, no compensating chains are needed, and greater travel
heights become feasible -- with aramid ropes, travel heights as high as 2,400 meters can
be implemented. Due to the rope's high coefficient of friction and reverse-bending
strength, smaller traction sheaves can be used, and the wear on them is reduced
practically to zero. By comparison with conventional steel ropes, the fully synthetic
elevator ropes give longer service and are also ecologically advantageous since they
require absolutely no lubrication throughout their entire life. Every second strand of the
elevator rope also contains an electrically-conductive carbon fiber, which is used for
permanent electronic monitoring of the slightest damage or wear on the aramid rope. This
makes it possible to diagnose the condition of the ropes either on the spot, or remotely
from anywhere else in the world.
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While conventional wisdom holds that laser
light on an object will cause the object to heat, research at Los Alamos has demonstrated
that cooling can occur under certain circumstances. Optical cooling, based on a principle
known as anti-Stokes fluorescence, occurs when the amount of energy emitted by a
solid, exposed to an energy source, is more than the energy it absorbs. In one device, the
Los Alamos Solid-State Optical Refrigerator, a 1.6W laser cools ytterbium-doped fluoride
glass a total of 97°F, starting from room temperature. Self-contained prototype LASSORs
are now under construction with diode lasers packing 10 times the power of the test
configuration. Such devices can be used in space for cooling detectors and instruments,
and eventually in desktop computers for cooling high-speed superconducting circuits. In
another development, a small heat pipe using lithium inside a molybdenum tube has shown
its capability to transfer large quantities of heat with almost no change in temperature.
After 40 years of research and development at the lab, these tubes can operate at
temperatures approaching 2,200°F, with the vaporized lithium within the tube transferring
heat energy at a power density of around 6 kW per cm2, about the same as the
heat emitted from the sun's surface. Applications include aerospace, chip-cooling and
nuclear reactors.
Elevator designers are constrained by the
weight and strength of steel cables to shafts no higher than 600 meters, with large
equipment rooms to contain the massive motor and gearworks. Schindler Management Ltd,
Ebikon, Switzerland, has introduced into the European market the first fully synthetic
elevator ropes, manufactured from aramid. SchindlerAramid ropes provide the same breaking
strength as steel ropes but with much lower weight, and they also have a high coefficient
of friction and high reverse-bending strength. As a result, for a given rated load, much
smaller drive machines can be used, no compensating chains are needed, and greater travel
heights become feasible -- with aramid ropes, travel heights as high as 2,400 meters can
be implemented. Due to the rope's high coefficient of friction and reverse-bending
strength, smaller traction sheaves can be used, and the wear on them is reduced
practically to zero. By comparison with conventional steel ropes, the fully synthetic
elevator ropes give longer service and are also ecologically advantageous since they
require absolutely no lubrication throughout their entire life. Every second strand of the
elevator rope also contains an electrically-conductive carbon fiber, which is used for
permanent electronic monitoring of the slightest damage or wear on the aramid rope. This
makes it possible to diagnose the condition of the ropes either on the spot, or remotely
from anywhere else in the world.
While conventional wisdom holds that laser
light on an object will cause the object to heat, research at Los Alamos has demonstrated
that cooling can occur under certain circumstances. Optical cooling, based on a principle
known as anti-Stokes fluorescence, occurs when the amount of energy emitted by a
solid, exposed to an energy source, is more than the energy it absorbs. In one device, the
Los Alamos Solid-State Optical Refrigerator, a 1.6W laser cools ytterbium-doped fluoride
glass a total of 97°F, starting from room temperature. Self-contained prototype LASSORs
are now under construction with diode lasers packing 10 times the power of the test
configuration. Such devices can be used in space for cooling detectors and instruments,
and eventually in desktop computers for cooling high-speed superconducting circuits. In
another development, a small heat pipe using lithium inside a molybdenum tube has shown
its capability to transfer large quantities of heat with almost no change in temperature.
After 40 years of research and development at the lab, these tubes can operate at
temperatures approaching 2,200°F, with the vaporized lithium within the tube transferring
heat energy at a power density of around 6 kW per cm2, about the same as the
heat emitted from the sun's surface. Applications include aerospace, chip-cooling and
nuclear reactors.