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Size-selective procedures were developed for the preparation of fiber fractions of uniform size of chrysotile, crocidolite, amosite and glass. The raw material was first ground to a suitable fineness, then prescreened in a vibrating bed aerosol generator and finally suspended in liquids by ultrasonic agitation. Size-separation was then achieved by slow(More)
Emissions of fibrous aerosols were measured on buildings with weathered and corroded asbestos-cement-plates (roofing and facade shingles) by means of an already published equipment and procedure. The measured emission factors for asbestos fibers longer than 5 microns were in the range of 10(6) to 10(8) fibers/m2.h. They depended on the type of the AC-plates(More)
In structurally disordered solids, some atoms or small groups of atoms are able to quantum mechanically tunnel between two nearly equivalent sites. These atomic tunneling systems have been identified as the cause of various low-temperature anomalies of bulk glasses and as a source of decoherence of superconducting qubits where they are sparsely present in(More)
In preparing fiber suspensions for biological applications, as well as in many analytical procedures, the fibers--e.g. asbestos and glass--often have to be mechanically diminished and ultrasonically treated. Such treatments may sometimes produce changes in the physical and chemical properties of the original fiber samples. Measurements have been made to(More)
Parasitic two-level tunnelling systems originating from structural material defects affect the functionality of various microfabricated devices by acting as a source of noise. In particular, superconducting quantum bits may be sensitive to even single defects when these reside in the tunnel barrier of the qubit's Josephson junctions, and this can be(More)
We report investigations of conductance fluctuations (with 1/f(alpha) power spectra) in doped silicon at low temperatures (T<20 K) as it is tuned through the metal-insulator transition (MIT) by changing the carrier concentration n. The scaled magnitude of noise, gamma(H), increases with decreasing T following an approximate power law gamma(H) approximately(More)
Recent progress with microfabricated quantum devices has revealed that an ubiquitous source of noise originates in tunneling material defects that give rise to a sparse bath of parasitic two-level systems (TLSs). For superconducting qubits, TLSs residing on electrode surfaces and in tunnel junctions account for a major part of decoherence and thus pose a(More)
Ambient air concentrations of fibrous dusts were measured in the vicinity of buildings with weathered and corroded asbestos-cement (AC)-products during 1983-1985. The concentrations of the total dust (TSP) were higher (mean value of 150 micrograms/m3) than the background concentrations. The mean value of ambient air asbestos concentrations lay at 750(More)
It could be already shown that fibrous particulates can be emitted from weathered and corroded surfaces of asbestos-cement-(AC)-products and that these fibers increase the total ambient air concentration after having been dispersed in the atmosphere. In this investigation we studied the influence of the polluted atmosphere on physical and chemical(More)