High-emittance coatings on metal substrates

High-emittance coatings of iron, calcium, and zirconium titanates thermally sprayed on stainless steel, columbium-1 percent zirconium, and beryllium substrates promote and control radiative heat transfer from the metal substrates. Adherence, compatibility and emittance stability at elevated temperature and high vacuum were evaluated

Determination of the emissivity of materials Semiannual progress report, 15 May - 14 Nov. 1966

Emittance and thermal cycling tests of stainless steel tubes coated with iron and calcium titanate, and niobium-zirconium tubes coated with iron titanat

Properties of high emittance materials

High emittance coating materials for beryllium, niobium-zirconium compounds, and stainless steel used in spacecraft radiator

Determination of the emissivity of materials Semiannual progress report, May 15 - Nov. 14, 1965

Selection of high emittance coatings for nuclear space power plant radiators - characteristics of iron titanate, calcium titanate, and aluminum oxide-aluminum titanate coating

Time-courses in the retention of food material in the bivalves \u3cem\u3ePotamocorbula amurensis\u3c/em\u3e and \u3cem\u3eMacoma balthica\u3c/em\u3e: significance to the absorption of carbon and chromium

Time courses for ingestion, retention and release via feces of microbial food was investigated using 2 bivalves with different feeding strategies, Potamocorbula amurensis, and Macoma balthica. The results showed 2 pathways for the uptake of food material in these clams. The first is represented by an initial label pulse in the feces. The second pathway operates over longer time periods. Inert 51Cr-labeled beads were used to determine time frames for these pathways. The first pathway, involving extracellular digestion and intestinal uptake, is relatively inefficient in the digestion of bacterial cells by P. amurensis but more efficient in M. balthica. The second pathway involving intracellular digestion within the digestive gland of both clams, was highly efficient in absorbing bacterial carbon, and was responsible for most chromium uptake. Differences in the overall retention of microbial 51Cr and 14C relate not to gut passage times but to the processing and release strategies of the food material by these 2 clams

Humic and fulvic acids: sink or source in the availability of metals to the marine bivalves \u3cem\u3eMacoma balthica\u3c/em\u3e and \u3cem\u3ePotamocorbula amurensis\u3c/em\u3e?

Humic acids (HA) and fulvic acids (FA) are common forms of organic matter in marine sediments, and are routinely ingested by deposit- and suspension-feeding animals. These compounds may be a sink for metals, implying that once metals are bound to humic substances they are no longer available to food webs. A series of experiments was conducted to quantitatively examine this premise using 2 estuarine bivalves from San Francisco Bay, USA: the suspension feeder Potarnocorbula arnurensis and the facultative deposit feeder Macoma balthica. HA and FA, isolated from marine sediments, were bound as organic coatings to either hydrous ferric oxides (HFO) or silica particles. Cd and Cr(III) were adsorbed to the organic coatings or directly to uncoated HFO and silica particles. Pulse-chase laboratory feeding experiments using 109Cd and 51Cr(III) were then conducted to determine absorption efficiencies of Cd and Cr for individual specimens using each of the particle types. The results demonstrated that: (1) absorption of Cr(III) from all types of non-living particles was consistently low (\u3c 11%). Ingested Cd showed greater bioavailability than Cr(III), perhaps due to differences in metal chemistry. (2) Bivalves absorbed Cd bound to uncoated HFO or silica particles (i.e. with no HA or FA present). (3) The presence of organic coatings on particles reduced Cd bioavailability compared with uncoated particles. (4) Both geochemical and biological conditions affected the food chain transfer of Cd. The data suggest that in marine systems inorganic and organic-coated particles are predominantly a sink for Cr in sediments. In the transfer of Cd to consumer animals, inorganic particles and humic substances can act as a link (although not a highly efficient one) under oxidized conditions

The role of bacterial exopolymer and suspended bacteria in the nutrition of the deposit-feeding clam, Macoma balthica

Potential nutritional contributions of bacterial exopolymer and suspended bacteria to the detritus feeding estuarine clam, Macoma balthica, were examined separately in laboratory 14C labelling experiments. Significant removal and assimilation of suspended bacteria by M. balthica was observed within two days, although the low clearance rates suggested planktonic bacteria may not be among its major food sources. Sediment-bound and dissolved bacterial exopolymer did not appear to be directly metabolized by M. balthica, as evidenced by the 1–2 week lag in 14C uptake into clam tissue

Determination of the emissivity of materials Semiannual progress report, 15 Nov. 1965 - 14 May 1966

Emissivity of titanate-coated stainless steel, niobium-zirconium alloy, and beryllium for space radiator

Wind-tunnel Studies at Subsonic and Transonic Speeds of a Multiple-mission Variable-wing-sweep Airplane Configuration

Wind tunnel studies at supersonic and transonic speeds to determine aerodynamic characteristics of variable sweep wing aircraft - configuratio

Local in time master equations with memory effects: Applicability and interpretation

Non-Markovian local in time master equations give a relatively simple way to describe the dynamics of open quantum systems with memory effects. Despite their simple form, there are still many misunderstandings related to the physical applicability and interpretation of these equations. Here we clarify these issues both in the case of quantum and classical master equations. We further introduce the concept of a classical non-Markov chain signified through negative jump rates in the chain configuration.Comment: Special issue on loss of coherence and memory effects in quantum dynamics, J. Phys. B., to appea