Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “phosphate”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

The chemical/physical and microbiological characteristics of typical bath and laundry waste waters

Chemical/physical and microbiological characteristics are studied of typical bath and laundry waters collected during a 12 day test in which the untreated waste waters were reused for toilet flush. Most significant changes were found for ammonia, color, methylene blue active substances, phosphates, sodium, sulfates, total organic carbon, total solids, and turbidity in comparison with tap water baseline. The mean total number of microorganisms detected in the waste waters ranged from 1 million to 10 to the 7th power cells/m1 and the mean number of possible coliforms ranged from 10 to the 5th power to 1 million. An accumulation of particulates and an objectible odor were detected in the tankage used during the 12 day reuse of the untreated waste waters. The combined bath and laundry waste waters from a family of four provided 91 percent of the toilet flush water for the same family.

Hypes, W. D.↗
NASA NTRS1974

Effect of chlorine purification on oxidation resistance of some mechanical carbons

Oxidation experiments were conducted with some experimental and commercial mechanical carbons at 650 C in dry air flowing at 28 cc/sec (STP). In general, purification of these carbon-graphites with chlorine at 2800 C improved oxidation resistance. Additional improvements in oxidation resistance were obtained from purification followed by an antioxidant (zinc phosphate) treatment. For the commercial materials, purification alone gave greater oxidation resistance than the antioxidant treatment alone. The reverse, however, was the case for the experimental materials.

Wisander, D. W.↗
NASA NTRS1974

Geologic interpretation of ERTS-1 satellite images for West Aswan Area, Egypt

ERTS-1 images of West Aswan area were interpreted in terms of geology, drainage, and structure. Twenty-two geological units were distinguished on ERTS-1 images in West Aswan area covering geological formations and erosional levels within some formations ranging from the Precambrian to the Quaternary. Apart from the distinction of Aswan monumental granite the investigated area shows very interesting exposures of sedimentary rocks ranging from the Cretaceous to the Quaternary. Of special interest is the delineation of the iron-ore member of the Nubian Sandstone and the phosphate-bearing formation. The tracing of the geological formations from south to north and the distinction of the varied geological units within the Pliocene and Quaternary, and the discussion on the origin of tufa are of particular significance. Also, the tracing on these images of major fractures and faults intercepting Aswan Dam Reservoir and their significance on the seepage and possible future development of diversion channels from reservoir is emphasized.

Elshazly, E. M.↗
NASA NTRS1973

Geochemistry of primordial Pb, Bi, and Zn in Apollo 15 samples

Primordial Pb as Pb-204 is present in Apollo 15 samples in concentrations ranging from less than 0.2 ppb in basalts to 6 ppb in soils. An acid soluble, pH-5-6, readily volatile component of this Pb is present, possibly as PbBr2; the remainder is correlated with the metal content of the sample. Leachable Bi and Pb-204 are correlated; residual Bi is probably present in a phosphate, possibly apatite. Zn is also highly leachable; residual Zn and Pb-204 are correlated.

Allen, R. O., Jr.↗
NASA NTRS1974

Enrichment of heavy nuclei in the April 17, 1972 solar flare

Cosmic ray nuclei from the April 17, 1972 solar flare were recorded in polycarbonate plastic and phosphate glass track detectors exposed on the Apollo 16 flight. The energy spectra of iron group nuclei and of carbon and heavier nuclei were measured down to about 0.02 MeV/nucleon, revealing that the enrichment of iron relative to carbon and heavier nuclei increases markedly in this very low energy region.

Fleischer, R. L.↗
NASA NTRS1974

Effect of 14 days of bed rest on urine metabolite excretion and plasma enzyme levels

After 1 week of ambulatory base-line measurement, a group of 8 men 19-26 years of age remained continuously recumbent for 14 days. Studies were continued for 1 week following the prolonged recumbency. Urine excretion rates for a number of constituents were determined 2 days before bed rest, on day 14 of bed rest, and day 6 after bed rest. Blood plasma samples were also obtained at these times, and analyzed for several enzymes. On day 14 of bed rest significant increases were observed in urine excretion of total osmotically-active substances, magnesium, calcium, phosphate, creatinine, hydroxyproline, and 17-OH corticosteroids. A decrease occurred in urinary glucose excretion. Plasma levels of alkaline phosphatase and LDH-3 were depressed, while plasma GPT was elevated. Many of these changes persisted on day 6 after bed rest, and are interpreted as concomitants of the disuse atrophy of the musculoskeletal system that characterizes prolonged bed rest and weightlessness.

Pace, N.↗
NASA NTRS1974

The prebiotic synthesis of deoxythymidine oligonucleotides

Deoxythymidine 5 prime-triphosphate in the presence of deoxythymidine 5 prime-phosphate, cyanamide and 4-amino-5-imidazole carboxamide polymerizes under drying conditions at moderate temperatures (60 to 90 C) to yield oligonucleotides of up to four units in length. Enzymatic analysis indicated that the majority of these oligomers contained natural 3 prime-5 prime phosphodiester bonds. This reaction offers a possible method for the formation of deoxyoligonucleotides under primitive earth conditions.

Stephen-Sherwood, E.↗
NASA NTRS1975

Improved ion exchange membrane

Membrane, made from commercially-available hollow fibers, is used in reverse osmosis, or dialysis. Fiber has skin layers which pass only small molecules. Macromolecules cannot penetrate skin. Fibers can also be used to remove other undesirable anions, such as phosphate, sulfate, carbonate, and uranium in form of uranium-sulfate complex.

Rembaum, A.↗
NASA NTRS1974

In vivo measurement of human body composition

The female bed rest study has shown that, the response of women to prolonged recumbency of 2 to 3 weeks duration is very similar to that displayed by men. Some of the key findings in the women after 17 days of continuous recumbency are: (1) a decrease in plasma volume of 12-13 per cent; (2) a small decrease in total body water; (3) a decrease in total body potassium of 3 to 4 per cent; (4) a decrease in plasma potassium concentration of 4 to 5 per cent; (5) a decrease in total circulating plasma protein of 11 to 12 per cent; (6) a decrease in urinary norepinephrine excretion rate of 27 to 28 per cent; (7) a possible increase in urinary magnesium, calcium, and phosphate excretion rates; and (8) a possible increase in urinary citrate excretion rate.

Pace, N.↗
NASA NTRS1975

Wear and friction of oxidation-resistant mechanical carbon graphites at 650 C in air

Studies were conducted to determine the friction and wear properties of experimental carbon-graphites. Hemispherically tipped carbon-graphite rider specimens were tested in sliding contact with rotating Inconel X-750 disks in air. A surface speed of 1.33 m/sec, a load of 500 g, and a specimen temperature of 650 C were used. Results indicate: (1) hardness is not a major factor in determining friction and wear under the conditions of these studies. (2) Friction and wear as low as or lower than those observed for a good commercial seal material were attained with some of the experimental materials studied. (3) The inclusion of boron carbide (as an oxidation inhibitor) has a strong influence on wear rate. (4) Phosphate treatment reduces the friction coefficient when boron carbide is not present in the base material.

Allen, G. P.↗
NASA NTRS1975

Aquatic plants for removal of mevinphos from the aquatic environment

Fragrant waterlily (Nymphaea odorata, Ait.), joint-grass (Paspalum distichum L.), and rush (Juncus repens, Michx.) were used to evaluate the effectiveness of vascular aquatic plants in removing the insecticide mevinphos (dimethyl-1-carbomethoxy-1propen-2-yl phosphate) from waters contaminated with this chemical. The emersed aquatic plants fragrant waterlily and joint-grass removed 87 and 93 ppm of mevinphos from water test systems in less than 2 weeks without apparent damage to the plants; whereas rush, a submersed plant, removed less insecticide than the water-soil controls. Water-soil control still contained toxic levels of this insecticide, as demonstrated by fish bioassay studies, after 35 days.

Wolverton, B. C.↗
NASA NTRS1975

Study of the thermal degradation mechanism of a composite propellant

The current experimental program was designed to systematically investigate the role of the oxidizer in the thermal degradation process of composite propellants. The scanning electron microscope (SEM) was used to examine the failure sites in thermally degraded propellant samples. The formulation variables tested were oxidizer purity, oxidizer particle size, and oxidizer to binder bonding agent. The binder, a saturated hydrocarbon, was kept constant throughout the experiments. The oxidizers were: AP, chlorate-doped AP, arsenate-doped AP, and phosphate-doped AP. The oxidizer particle size distribution was 60% of the large fraction and 40% of the small fraction. The bonding agent, when present, was used at the 0.15% level. The data showed that both the oxidizer purity and particle size had an important affect on the thermal degradation process. The affect of the oxidizer particle size was more noticeable at the higher temperature and stress levels. An examination of the failure site, by SEM, of propellants subject to these latter conditions indicated that the fracturing of the large oxidizer particles led to the propellant cracking.

Schmidt, W. G.↗
NASA NTRS1974

Prebiotic chemistry and nucleic acid replication

Recent work is reviewed on some reactions that could have occurred on the primitive earth and that could have played a part in the evolution of a self-replicating system. The transition from the primitive atmosphere to the simplest replicating molecules is considered in four stages: (1) the formation of a 'prebiotic soup' of organic precursors, including the purine and pyrimidine bases and the pentose sugars; (2) the condensation of these precursors and inorganic phosphate to form monomeric nucleotides and activated nucleotide derivatives; (3) the polymerization of nucleotide derivatives to oligonucleotides; and (4) the complementary replication of oligonucleotides in a template-directed process that depends on Watson-Crick base pairing.

Orgel, L. E.↗
NASA NTRS1975

An optical/digital processor - Hardware and applications

A real-time two-dimensional hybrid processor consisting of a coherent optical system, an optical/digital interface, and a PDP-11/15 control minicomputer is described. The input electrical-to-optical transducer is an electron-beam addressed potassium dideuterium phosphate (KD2PO4) light valve. The requirements and hardware for the output optical-to-digital interface, which is constructed from modular computer building blocks, are presented. Initial experimental results demonstrating the operation of this hybrid processor in phased-array radar data processing, synthetic-aperture image correlation, and text correlation are included. The applications chosen emphasize the role of the interface in the analysis of data from an optical processor and possible extensions to the digital feedback control of an optical processor.

Casasent, D.↗
NASA NTRS1975

Discrete component bonding and thick film materials study

The results are summarized of an investigation of discrete component bonding reliability and a fundamental study of new thick film resistor materials. The component bonding study examined several types of solder bonded components with some processing variable studies to determine their influence upon bonding reliability. The bonding reliability was assessed using the thermal cycle: 15 minutes at room temperature, 15 minutes at +125 C 15 minutes at room temperature, and 15 minutes at -55 C. The thick film resistor materials examined were of the transition metal oxide-phosphate glass family with several elemental metal additions of the same transition metal. These studies were conducted by preparing a paste of the subject composition, printing, drying, and firing using both air and reducing atmospheres. The resulting resistors were examined for adherence, resistance, thermal coefficient of resistance, and voltage coefficient of resistance.

Kinser, D. L.↗
NASA NTRS1976

Plasticized phenolphthalein polycarbonate

Phenolphthalein polycarbonate was successfully plasticized with polychlorinated biphenyls (e.g., Aroclor 1231) or tricresyl phosphate and cast from tetrahydrofuran to give clear films without loss of fire resistance. At loadings of 20 to 30 percent plasticizer the Tg was lowered to approximately 100 C which would render phenolphthalein polycarbonate easily moldable. Although these materials had some mechanical integrity as shown by their film forming ability, the room temperature toughness of the plasticized polymer was not significantly improved over unmodified polymer.

Harrison, E. S.↗
NASA NTRS1976

Response of selected microorganisms to experimental planetary environments

Results are presented on the anaerobic conversion of phosphite to phosphate. It is demonstrated that in the presence of both phosphite and hypophosphite, the phosphite is the preferred phosphorous source. An investigation in which P-32 labeled hypophosphite was added to the basal medium demonstrates that the labeled hypophosphite was incorporated into the metabolic reactions of the cell. Other data show that as cell growth occurs, the phosphite and/or hypophosphite levels decrease. The Bacillus sp. capable of anaerobic utilization of phosphite was isolated from Cape Canaveral soil samples, and it is partially characterized. Also included are continued investigations of omnitherms. The data presented show that some of these possess significant resistance to the Viking dry-heat cycle, and that they retain their omnithermic characteristic after recovery from the heat cycle. Other physiological characteristics of these isolates are also presented. It is demonstrated that omnitherms can be isolated from Cape Canaveral soil.

Foster, T. L.↗
NASA NTRS1975

Cyanogen induced phosphorylation of D-fructose

It has been demonstrated that a phosphorylated sugar, identified as alpha-D-fructopyranose, can be formed as the result of cyanogen-induced phosphorylation of D-fructose at pH 8.8. The product was isolated from barium and cyclohexylammonium salts and identified on the basis of its chromatographic and electrophoretic properties, its lability to hydrolysis by alkaline phosphatase, the rate of its acid-catalyzed hydrolysis, and the results of periodate oxidation and optical rotatory measurements. These results support the suggestion that the cyanogen-induced phosphorylation of free sugars could be a possible process for formation of sugar phosphates under prebiotic conditions (Halman et al., 1969).

Degani, CH.↗