We relate possible cosmological variations in the mass ratio μ ≡ m p /m e and the fine structure constant α to long range composition-dependent forces mediated by a scalar field. The differential acceleration η in Eötvös-type experiments is bounded below by 10 −14 , except in cases where one or more scalar couplings vanish. We consider what values for these couplings could arise from unified theories. By considering the contribution of the scalar field to the cosmological energy density we use bounds on η to put upper bounds on the current rate of change of μ and α.
A new type semiconductor, which shows an abrupt resistance change of 2–4 orders of magnitude at about 68°C with negative temperature coefficient, has been prepared by sintering a mixture of V2O5 and an acidic oxide (B, Si or P oxide) or a basic oxide (Mg, Ca, Sr or Ba oxide) in a suitable reducing atmosphere. It has been found that there are some optimum conditions of sintering and reducing for obtaining such remarkable characteristics.
Life of the samples obtained under suitable conditions is theoretically estimated to be several ten years in air at 200°C. The large temperature coefficient of resistance of this newly developed semiconductor, which is thirty times as large as the magnitude of the usual thermistor, suggests many useful applications.
A heat engine called a pulse tube engine has been recently proposed, which consists of only a few parts, namely, differentially heated stacked metal meshes in a cylinder and one piston, coupled to a flywheel. We built the prototype engine and tested its working mechanism from the standpoint of a thermoacoustic framework. We measured the work flux density distribution over the cross section of the pulse tube to elucidate the work source of the engine. This engine belongs to the standing wave engine group and the work source resides not in the stacked metal meshes but in the pulse tube.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.