Catalysis of hydrogen-atom recombination in rocket nozzles

Oxygen and oxygen-nitrogen mixtures as catalysts for hydrogen atom recombination in rocket nozzle

Estimates of nonequilibrium ionization phenomena in the inviscid Apollo plasma sheath

Nonequilibrium ionization in asymmetric plasma sheath determined for Apollo spacecraft at superorbital velocity reentr

Time-division SQUID multiplexers with reduced sensitivity to external magnetic fields

Time-division SQUID multiplexers are used in many applications that require exquisite control of systematic error. One potential source of systematic error is the pickup of external magnetic fields in the multiplexer. We present measurements of the field sensitivity figure of merit, effective area, for both the first stage and second stage SQUID amplifiers in three NIST SQUID multiplexer designs. These designs include a new variety with improved gradiometry that significantly reduces the effective area of both the first and second stage SQUID amplifiers.Comment: 4 pages, 7 figures. Submitted for publication in the IEEE Transactions on Applied Superconductivity, August 201

Strongly quadrature-dependent noise in superconducting micro-resonators measured at the vacuum-noise limit

We measure frequency- and dissipation-quadrature noise in superconducting lithographed microwave resonators with sensitivity near the vacuum noise level using a Josephson parametric amplifier. At an excitation power of 100~nW, these resonators show significant frequency noise caused by two-level systems. No excess dissipation-quadrature noise (above the vacuum noise) is observed to our measurement sensitivity. These measurements demonstrate that the excess dissipation-quadrature noise is negligible compared to vacuum fluctuations, at typical readout powers used in micro-resonator applications. Our results have important implications for resonant readout of various devices such as detectors, qubits and nano-mechanical oscillators.Comment: 13 pages, 4 figure

Gender patterns in dress and outward appearance: an individual choice or fulfillment of cultural expectations?

This study examines the extent to which males and females conform to gender schemas regarding outward appearance and clothing styles. Participants were observed from a distance in various natural settings and were coded based on estimated age, hair length, certain clothing choices, and certain jewelry and accessory choices. We found statistically significant gender differences (with p \u3c.0001) for all characteristics, with the codes for hair length, earrings, and dresses showing the strongest discrepancies. These data showed a pattern of males being more confined to strict gender displays than were females, which can be seen particularly clearly in the wearing of earrings and dresses, as males rarely deviated from the socially acceptable gender signals. These findings imply that the feminist movement loosened feminine standards for dress and appearance; lacking a similar social movement, men remain more strictly confined to traditional displays of gender

Advanced code-division multiplexers for superconducting detector arrays

Multiplexers based on the modulation of superconducting quantum interference devices are now regularly used in multi-kilopixel arrays of superconducting detectors for astrophysics, cosmology, and materials analysis. Over the next decade, much larger arrays will be needed. These larger arrays require new modulation techniques and compact multiplexer elements that fit within each pixel. We present a new in-focal-plane code-division multiplexer that provides multiplexing elements with the required scalability. This code-division multiplexer uses compact lithographic modulation elements that simultaneously multiplex both signal outputs and superconducting transition-edge sensor (TES) detector bias voltages. It eliminates the shunt resistor used to voltage bias TES detectors, greatly reduces power dissipation, allows different dc bias voltages for each TES, and makes all elements sufficiently compact to fit inside the detector pixel area. These in-focal-plane code-division multiplexers can be combined with multi-gigahertz readout based on superconducting microresonators to scale to even larger arrays.Comment: 8 pages, 3 figures, presented at the 14th International Workshop on Low Temperature Detectors, Heidelberg University, August 1-5, 2011, proceedings to be published in the Journal of Low Temperature Physic

High speed imaging and Fourier analysis of the melt plume during close coupled gas atomisation

A high speed digital analysis technique has been used to study the atomisation plume of a superheated sample of Ni–Al in a close coupled gas atomiser. The atomisation, incorporating a generic melt nozzle and die design was captured using a Kodak high speed digital analyser at a frame rate of 18 k frames per second. The resulting 65 536 frames were then analysed using a specially designed routine, which calculates values of optical brightness and position of the intensity maximum for all frames and performs Fourier analysis on the sequence. The data produced from this analysis show that the plume, pulses at low frequencies (<25 Hz) and precesses at higher frequencies (∼360 Hz) around the atomiser's centreline. To aid investigation into the origins of this precession and other phenomena it was decided to conduct further experiments using an analogue system. The analogue atomiser reproduces the important features of the full atomiser but instead of atomising molten metal, the analogue system atomises water, providing a quick and easy way of testing the effects of changing parameters. Using this system it was found that the precession of the melt plume is independent of the atomiser's gas inlet pressure but strongly dependent on both the die and melt nozzle's geometry

Metabolic changes upon GLS inhibition by CB-839 in glioma cell lines

Many tumors use Gln for both energy generation and as a biosynthetic precursor. Glutaminases (GAs) catalyze the first step of glutaminolysis by converting glutamine (Gln) into glutamate and ammonia in the mitochondria. In humans, two genes encode for glutaminases: GLS and GLS2. We examined the metabolic consequences of inhibiting GLS activity in glioma cells by using the clinically relevant inhibitor CB-839. We treated three glioblastoma (GBM) cell lines with CB-839 and performed untargeted metabolomics and isotope tracing experiments using U-13C-labeled Gln and 15N-labeled Gln in the amido group to ascertain the metabolic fates of Gln carbon and nitrogen. Untargeted metabolomics results showed that CB-839 treatment significantly depleted tricarboxylic acid cycle (TCAC) intermediates and related metabolites in the three human glioblastoma cell lines assayed. This result was also confirmed by a lower labeling from U-13C- Gln in these metabolites. U-13C- Gln tracing also revealed reductive carboxylation-related labeling in these cell lines, and this pathways was also suppressed by CB-839. Metabolomics results showed an accumulation of the de novo purine biosynthesis intermediates inosine monophosphate and/or AICAR, and a decrease in uridine monophosphate, while 15N-Gln tracing results showed a decreased labeling from Gln amido group in AMP, GMP, UMP and CTP in T98G cell line when treated with CB-839. Finally, metabolomics showed higher levels of trimethyllysine and, in T98G cells, a 22-fold increase in 5-methyl-cytosine.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech