Abstract: A steel wire which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present embodiment consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, N: 0.0070% or less, Ca: 0 to 0.0050%, and Nb: 0 to 0.020%, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/?m2.

Abstract: A valve spring includes a nitrided layer, and a core portion that is further inward than the nitrided layer. A chemical composition of the core portion consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr: 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Ca: 0.0001 to 0.0050%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, and N: 0.0070% or less, with the balance being Fe and impurities. In the core portion, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 per ?m2, and in the core portion, a numerical proportion of Ca sulfides with respect to a total number of oxide-based inclusions and sulfide-based inclusions is 0.20% or less.

Abstract: An upcoated optical fiber includes an optical fiber having a ultra-violet (UV) curable upcoating and a slip layer disposed between the optical fiber and the upcoating. The upcoating is mechanically strippable from the optical fiber and may be colored for identification of the optical fiber. In one embodiment, the slip layer and upcoating both have predetermined glass transition temperatures that are within about 15° C. of each other for improving mechanical characteristics. The slip layer may be essentially the same color as the upcoating for identification of the optical fiber after the upcoating is removed or it may be uncolored. In suitable embodiments, the slip layer may include a micronized poly-tetra-fluoro-ethylene (PTFE), a silicone, and/or a dispersing agent for enhancing the strip performance of the upcoating over a range of temperatures.

Abstract: An upcoated optical fiber includes an optical fiber having a ultra-violet (UV) curable upcoating and a slip layer disposed between the optical fiber and the upcoating. The upcoating is mechanically strippable from the optical fiber and may be colored for identification of the optical fiber. In one embodiment, the slip layer and upcoating both have predetermined glass transition temperatures that are within about 15° C. of each other for improving mechanical characteristics. The slip layer may be essentially the same color as the upcoating for identification of the optical fiber after the upcoating is removed or it may be uncolored. In suitable embodiments, the slip layer may include a micronized poly-tetra-fluoro-ethylene (PTFE), a silicone, and/or a dispersing agent for enhancing the strip performance of the upcoating over a range of temperatures.

Abstract: A ventilator of the heat exchange type includes an air passageway communicating between an interior of a room to be ventilated and the outdoors, a first centrifugal fan for introducing outdoor air to the interior of the room, a second centrifugal fan for discharging indoor air outdoors, both centrifugal fans being disposed within the air passageway so that outlet areas communicates to each other, and two electric motors for alternately driving the centrifugal fans respectively. At least any one of the centrifugal fans is formed of a heat-accumulative material so that heat contained in the indoor air is accumulated in the centrifugal fan formed of the heat-accumulative material and that the heat accumulated in the centrifugal fan is dissipated to the suction air. Heat exchange is thus performed by accumulating the heat in one of the centrifugal fans during indoor air discharge operation and by dissipating the heat to the outdoor air during outdoor air suction operation.

Abstract: A heat exchanger device including a core having a stack of parallel heat-conductive plates which are formed with corrugations for channeling air between the plates, each plate being fabricated from a single sheet. The corrugations of successive plates are offset from each other for providing both separation and support of the plates with respect to each other. The heat exchanger is the combination of the core and a ventilation unit in a single housing for ventilating primary and secondary air through respectively alternating pairs of successive plates.