Glass Capsules Research Articles

Measurement of void fraction in magnetic two-phase fluids

A solenoid sensor has been used to measure the void fraction in two-phase ferrofluid flow. The system of the solenoid sensor consists of a thin wire wounded around a glass tube, an ammeter and a band-pass filter. New theoretical equations were derived. In this magnetic technique, because the relative permeability of glass is equal to that of air, glass capsules were used as a stationary non-flow simulation for bubbly flow. Annular and core flows were simulated by the insertion of glass tubes with different diameters. Different wave forms (that is, sine, triangular, square and linear) were tested and used.

Direct-Drive Implosion Experiments on the SG-II Laser Facility

SG-II, a 8-beam Nd:glass laser with an output energy capability of 6kJ at 1.053μm, was built and direct-drive implosions were successfully performed early in 2000. Both exploding pusher and ablative targets were imploded using glass capsules with diameters of 200 and 500μm, and a wall thickness of about 1μm. The deuterium and tritium (DT) gas pressure filled in these capsules were 2.0 and 0.5MPa, respectively. Sophisticated diagnostics were deployed to measure laser absorption, hot electron temperature and fraction, thermal electron temperature, neutron yields, ion temperature, temporally resolved x-ray images, fuel areal density, alpha particle image, and so on. Significant results, such as neutron yields up to 4 × 109 for exploding pushers with 100-ps laser pulse irradiation and 6 × 108 for ablative targets with 1-ns pulses and clear x-ray images to see the compression process, were obtained. Numerical simulations were conducted to optimize target and laser parameter design and to duplicate the results afterwards with the specific shot parameters used in the experiment.

Pb diffusion in clinopyroxene

Chemical diffusion of Pb under anhydrous, pO 2-buffered conditions has been measured in natural clinopyroxenes of two different compositions: one a near-end-member diopside and the other of more iron-rich composition (∼40% diopside component). The sources of diffusant were fused and finely ground mixtures of PbS powder and ground pyroxene. Experiments were run in sealed silica glass capsules with a solid buffer (to buffer at QFM). Rutherford backscattering spectrometry (RBS) was used to measure diffusion profiles. The following Arrhenius parameters were obtained for diffusion normal to (110) over the temperature range 800–1100°C under QFM-buffered conditions: D=4.03×10 2exp(−544±40 kJ mol −1/ RT) m 2 s −1 (for Di 95) D=2.20×10 −4exp(−387±31 kJ mol −1/ RT) m 2 s −1 (for Di 40). Diffusion in the more iron-rich clinopyroxene is faster and activation energy for diffusion lower than that for the near-end-member diopside. Little dependence of Pb diffusion on crystallographic orientation was noted in diopside. Diffusion of Pb is comparable to that of Sr in natural diopside, but faster than many other species in clinopyroxenes. The activation energy for Pb diffusion in diopside is relatively high and Pb diffusivities are fairly slow when compared with the extant diffusion data for other minerals. It follows as consequence of these relatively slow diffusivities that Pb closure temperatures are higher in diopside than for most other minerals, with the exception of a few phases such as zircon and garnet. The faster diffusivities that characterize Fe-rich clinopyroxenes will lead to somewhat depressed closure temperatures, but clinopyroxenes in general should be fairly retentive of Pb isotopic information when subjected to all but the most extreme thermal events.

Organo-thermal crystal growth of α6 thiophene

Abstract Organic solvents contained in sealed glass capsules in the temperature range 150–250°C can dissolve 0.5 to ∼ 18 wt% of moderate molecular weight organic oligomers often as much as 10–100 × previously reported solubility. We report solubilities of α-hexathiophene (a promising thin film transistor material) as high as 18% and describe the growth of small crystals by slow cooling. This work suggests that previously recalcitrant organics may be grown as single crystals under “organo-thermal” conditions.

Mechanical Properties of Hydroxyapatite/Mica Composite

Bend specimens of the inorganic synthetic materials hydroxyapatite (HA) and a composite of hydroxyapatite/muscovite mica have been prepared and tested mechanically. Sintering followed by hot isostatic pressing (HIP) without encapsulation gave an increased strength for HA alone, but no significant increase in strength compared with sintering alone for HA/mica composites. The bend strength of the HA/mica composite was inferior to that of HA alone, the reason being inadequate bonding between HA and mica. HIP in glass capsules and an increased cold compaction pressure tended to improve the bend strength of the composite. Corrosion in tris for 7 d did not affect the bend strength of the investigated materials significantly.

Speciation in experimental C-O-H fluids produced by the thermal dissociation of oxalic acid dihydrate

Fluid speciations and their related reaction pathways were studied in C-O-H-system fluids produced by the thermal dissociation of oxalic acid dihydrate (OAD: H 2C 2O 4 · 2H 2O) sealed in silica glass capsules. Experiments were conducted in the temperature range 230–750°C, with bulk fluid densities in the range 0.01–0.53 g/cm 3. Pressure was controlled by temperature and density in the isochoric systems. The quenched products of dissociation experiments were an aqueous liquid and one (supercritical fluid) or, rarely, two (vapor plus liquid) carbonic phase (s). In-situ Raman microanalyses were performed on the quenched carbonic phases at room temperature, at which fluid pressures ranged from about 50 to 340 bars. Bulk fluid speciations were reconstructed from the Raman analyses via mass balance constraints, and appear to monitor the true fluid speciations at run conditions. In experiments from the lowtemperature range (230–350°C), fluid speciations record the dissociation of OAD according to the reaction OAD = CO 2 + CO + 3 H 2 O. A process of the form CO + H 2 O = CO 2 + H 2 is driven to the right with increasing temperature. The hydrogen gas produced tends to escape from the sample systems via diffusion into/through the silica glass capsules, shifting bulk compositions toward equimolar binary H 2O-CO 2 mixtures. The speciations of fluids in experiments with minimal hydrogen loss show poor agreement with speciations calculated for equilibrium fluids by the corresponding-states model of Saxena and Fei (1988). Such disagreement suggests that the formations of CH 4 and graphite are metastably inhibited in the current experiments, which correlates with their absence or trivial abundances in experimental products. Moreover, calculations in which the stabilities of methane and graphite are suppressed suggest that such metastable equilibrium is approached only in experiments at temperatures greater than about 600–650°C. These results have applications to fluid processes in geological environments, in addition to considerations of using oxalate compounds as volatile sources in experimental studies. It is possible that disequilibrium or metastable fluids may be entrapped as inclusions; re-speciation (toward metastable or stable equilibrium) during P-T evolution of a given terrain would place the fluid inclusion on a new isochore that would not project through the original conditions of entrapment. Moreover, the disequilibrium to metastable nature of dissociation reactions, coupled with the diffusional mobility of hydrogen gas observed in the current experiments, suggests that the predominance of binary H 2O-CO 2 fluid mixtures in natural inclusions from medium- to high-grade metamorphic terrains may be more than a coincidence of similar initial bulk compositions.

The long-term stability and reliability of photomultipliers used in Anger scintillation cameras

A test instrument has been designed to measure the stability of PMTs (photomultiplier tubes) used in Anger scintillation cameras. The instrument is composed of a number of glass capsules containing beta-emitting tritium with a blue phosphor to provide a very stable light source along with a data logger to monitor anode current. Three hundred and sixty PMTs were simultaneously tested for anode luminous sensitivity, dark current, long-term drift rate, erratic gain instabilities, and RMS noise. Results on the use of the instrument to test over 300000 PMTs are discussed, and the impact upon Anger camera reliability is assessed. It is concluded that the use of the test instrument has improved the reliability of the Anger scintillation camera through the elimination of PMTs that could compromise operating reliability. Field service of Anger cameras has been reduced by pretesting and accelerated aging of PMTs before installation into the instrument. The failure rate of PMTs tested by the instrument is less than one in 10/sup 7/ camera hours of operation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Igneous origin for the Na in the cloud of Io

We heated mixtures of sulfur and Na‐bearing silicates in evacuated silica glass capsules to temperatures between 600°C and 950°C. At or above 850°C, Na‐silicate glass reacts with elemental S to form a (Na,K) sulfide. Mobilization of this phase may account for the presence of Na and K on the surface of Io, and hence in the material sputtered into the Jovian magnetosphere.

Tritium handling facility at KMS Fusion Inc.

The tritium facility at KMS Fusion, Inc. supports the inertial confinement fusion research program. The main function of the facility is to fill glass and polymer Microshell (TM) capsules (small fuel containers) to a maximum pressure of 100 atm with tritium (T2) or deuterium–tritium (DT). The recent upgrade of the facility allows us to fill Microshell capsules to a maximum pressure of 200 atm. A second fill port allows us to run long term fills of Macroshell (TM) capsules (large fuel containers) concurrently. The principle processes of the system are: (1) storage of the tritium as a uranium hydride; (2) pressure intensification using cryogenics; and (3) filling of the shells by permeation at elevated temperatures. The design of the facility was centered around a NRC license limit of 6000 Ci.

Chronic nicotine and withdrawal effects on radial-arm maze performance in rats

Rats were tested for choice accuracy in an eight-arm radial maze during and after chronic administration of nicotine via subcutaneously implanted glass and Silastic capsules. Nicotine administration significantly improved choice accuracy relative to controls. The effect gradually became apparent over the first 2 weeks of exposure and persisted through the third week. Surprisingly, the significant facilitation of the nicotine-treated rats relative to controls continued for 2 weeks after the end of nicotine administration. No effects of nicotine were seen on choice latency or the strategy to make adjacent arm entries.

Radium Treatment for Hemangioma in Early Childhood: Reconstruction and dosimetry of treatments, 1920–1959

Between 1920 and 1959, a total of 14,647 children younger than 18 months were treated at Radiumhemmet with ionizing radiation for skin hemangioma. Seventy-two percent of the children were treated with radium needles or tubes, which were put into glass capsules and then applied to the hemangioma. The absorbed doses to different organs have been measured in a tissue equivalent phantom, representing a 6-month-old child. For a standard treatment of 8 Gy to the hemangioma the mean absorbed doses to the brain, eye lens, parotid gland, thyroid, breast anlage and gonads from 28 different treatment areas were 0.03-0.2 Gy. The mean absorbed dose to the organs in younger (less than 2 months) and older (14-18 months) children were up to 50% higher (0.04-0.1 Gy) and 33% lower (0.02-0.06 Gy) respectively, than for a 6-month-old child. The uncertainty in organ absorbed doses for each patient depended mostly on the estimation of the distance between the applicator and the site.

HIPing of silicon nitride with additive of BeAl 2O 4

Silicon nitride with a small amount of additive BeAl2O4 was sintered by HIP treatment in glass capsules. The sintered body of Si3N4 was for the most part β phase. BeAl2O4 dissolved into β-Si3N4 completely. The effect of isostatic pressure was significant in HIP sintering. For example, the bulk density of sintered body containing 3wt% BeAl2O4 was almost theoretical, and its microstructure was homogenous when sintered above 1700°C and at an applied pressure 200MPa.

Oxidation of Mild Steel Crevices in high pressure carbon dioxide

AbstractThe oxidation of mild steel crevices in pressurized carbon dioxide containing small amounts of carbon monoxide, hydrogen and water is analysed mathematically. For bulk gas which is hydrogen‐rich with respect to the water‐gas shift reaction equilibrium, conversion of hydrogen to water on magnetite surfaces is rapid. This, and the differential diffusion of hydrogen and water, lead to crevice gas compositions very different from the bulk gas.In restricted crevices, protective oxidation causes enhanced carbon monoxide concentration. In less restricted crevices, enhanced water concentrations are possible. Both situations lead to shorter times to breakaway oxidation than in the bulk gas.Crevice breakaway oxidation rates may be enhanced by a factor of 1.7 for suitable crevice geometry, provided that the bulk gas is not equilibrated at the crevice mouth. In more restricted crevices the rate is depressed.These predictions of the analysis are substantiated by experimental oxidation of mild steel specimens within inert glass capsules having a leak path. Such capsules provide a convenient method of exposing material to a wide range of gas compositions within the same autoclave.

TI3SbS4, eine neue Phase im System Tl?Sb?S Kurze Mitteilung

Tl3SbS4 was synthesized from TlS and TlSbS2 in evacuated silica glass capsules at 200°C in 18 days. DTA and X-ray diffraction data are given, and the problem of cation valencies is discussed.

Preservation of West Mediterranean members of the cruciferous tribe brassiceae

A seed preservation procedure is described whereby small samples are stored in individual glass capsules under anhydrous, anaerobic, and cold conditions. The method is being utilized for setting up a seed-bank of Cruciferae with emphasis on the tribe Brassiceae. This tribe has its maximum variability in the West Mediterranean countries—especially in Morocco, Algeria, and Spain. It includes a number of relatives of important horticultural crops, as well as a high proportion of endangered taxa which occupy small and scattered, relict areas in the region. Moreover, most Brassiceae are good examples of those members of the plant kingdom which are adapted to disturbed or semi-disturbed habitats, and of which protection within ecosystems raises a number of practical difficulties. For these species and lower taxa, gene-banks may play an important complementary role in conservation, as they may simultaneously improve the availability of plant material for research purposes.

The reaction between boron trichloride vapour and titanium

The reaction between boron trichloride vapour and titanium has been investigated in the temperature range 200–1350°C in sealed glass capsules and by a flow method, in which at the higher temperatures an electrically heated filament served as the reaction site. Under the various experimental conditions, titanium diboride, and titanium tetra- tri- and dichlorides have been obtained as reaction products. Their formation has been related to the experimental conditions and reconciled with the thermochemical properties of the system. In a closed reaction system at ∼450°C the formation of a metallic titanium mirror takes place by an unknown vapour transport and deposition process.

EXPERIMENTAL INVESTIGATION OF CHALCOCITE: ANNEALING AND PLASTIC DEFORMATION AT ELEVATED TEMPERATURES

The recrystallization behavior and deformation of synthetic chalcocite (Cu2S) in the temperature range 400–725 °C was studied microscopically after the compound was annealed in evacuated silica glass capsules and heated under differential pressures in sealed gold capsules. The temperature of recrystallization and grain growth ascribed to the hexagonal cubic inversion, at sulfur vapor pressures much less than 1 atmosphere, was determined at 465 ± 5 °C, with annealing time of [Formula: see text].Experiments involving differential pressures of 8 000 p.s.i. show that chalcocite in the solid state becomes considerably more mobile above 563 ± 10 °C and can readily be injected as a plastic mass to form veins without preservation of deformational textures.Natural bornite and natural galena may also be injected under differential pressure at 640 °C, but some unhealed fractures remain. Flow structure is well-preserved in galena and, under certain conditions, in bornite.Mixtures of bornite and pyrite flowed and recrystallized to chalcopyrite and bornite with exsolved chalcopyrite. No evidence of flowage remained.Chalcopyrite and pyrrhotite are resistant to injection under similar differential pressures and temperatures.

The systems bismuth-tellurium and antimony-tellurium and the synthesis of the minerals hedleyite and wehrlite

The synthesis of alloys in the systems Bi-Te and Sb-Te has been investigated using a technique in which the component elements are simultaneously heated and agitated in glass or silica capsules. Examination of X-ray powder diffraction patterns of alloys in the Bi-Te system shows that there is a range of solid solubility, designated the β-phase, between the composition limits of 32 and 60 at. per cent Te. X-ray diffraction data obtained for the minerals hedleyite and wehrlite show that these are naturally occurring β-phases with Te contents of about 30 and 52 at. per cent respectively. In the Sb-Te system, the range of solid solubility, designated the δ-phase, extends from 11 to 60 at. per cent Te. With the exception of Bi 2Te 3 and Sb 2Te 3 (the former is found in nature as the mineral tellurbismuth), the β- and δ-phases are relatively unstable and disproportionate when heated above their solidus temperatures. An attempt has been made to account for the changes in cell dimensions of the β- and δ-phase alloys, observed with decreasing Te content, in terms of the atomic configurations in the crystal structures of Bi 2Te 3 and Sb 2Te 3 and the derivative solid solutions. Phase equilibrium diagrams for the two systems are given.

Equilibrium relations between pyrrhotite and pyrite from 325 degrees to 743 degrees C

The pyrrhotite solvus that represents the compositions of pyrrhotite coexisting in equilibrium with pyrite was determined in the temperature range 325 degrees C. to 743 degrees C. by experiments conducted in sealed, evacuated, silica glass capsules and at pressures equal to that of the vapor in equilibrium with the condensed phases. Experiments conducted in sealed, collapsible Au tubes demonstrate that confining pressures of 2000 bars do not measurably affect the position of the solvus below 670 degrees C. The compositions of synthetic hexagonal pyrrhotite were measured within + or -0.13 atomic % Fe with the aid of an X -ray determinative curve that relates d (102) to composition. X-ray powder data and a general description are given for an unidentified lamellar iron sulfide phase occurring in rapidly quenched Fe-deficient pyrrhotite. Temperatures of crystallization of 10 natural pyrrhotite-pyrite assemblages are estimated using the pyrrhotite solvus. The temperature of crystallization of sphalerite coexisting with pyrrhotite and pyrite in 4 of these samples was also measured; the estimates obtained from the 2 methods, with very few exceptions, agree well within the experimental error.

Chemical Dosimetry of Gamma Rays, Neutrons and Accelerated Electrons

A ferrous sulfate dosimeter solution was irradiated in pyrex glass capsules from several laboratory Co/sup 60/ sources. The results are plotted in a graph. The standardized sources were then used to determine the effect of formic acid as an organic impurity on the ferrous sulfate dosimeter. (OID)