166 research outputs found
Peak Stir Zone Temperatures during Friction Stir Processing
The stir zone (SZ) temperature cycle was measured during the friction stir processing (FSP) of NiAl bronze plates. The FSP was conducted using a tool design with a smooth concave shoulder and a 12.7-mm step-spiral pin. Temperature sensing was accomplished using sheathed thermocouples embedded in the tool path within the plates, while simultaneous optical pyrometry measurements of surface temperatures were also obtained. Peak SZ temperatures were 990 â°Cto 1015 â°C (0.90 to 0.97 TMelt) and were not affected by preheating to 400â°C, although the dwell time above 900 â°C was increased by the preheating. Thermocouple data suggested little variation in peak temperature across the SZ, although thermocouples initially located on the advancing sides and at the centerlines of the tool traverses were displaced to the retreating sides, precluding direct assessment of the temperature variation across the SZ. Microstructure-based estimates of local peak SZ temperatures have been made on these and on other similarly processed materials. Altogether, the peak-temperature determinations from these different measurement techniques are in close agreement
Near-Infrared Imaging Polarimetry of Inner Region of GG Tau A Disk
By performing non-masked polarization imaging with Subaru/HiCIAO, polarized
scattered light from the inner region of the disk around the GG Tau A system
was successfully detected in the band with a spatial resolution of
approximately 0.07\arcsec, revealing the complicated inner disk structures
around this young binary. This paper reports the observation of an arc-like
structure to the north of GG Tau Ab and part of a circumstellar structure that
is noticeable around GG Tau Aa extending to a distance of approximately 28 AU
from the primary star. The speckle noise around GG Tau Ab constrains its disk
radius to <13 AU. Based on the size of the circumbinary ring and the
circumstellar disk around GG Tau Aa, the semi-major axis of the binary's orbit
is likely to be 62 AU. A comparison of the present observations with previous
ALMA and near-infrared (NIR) H emission observations suggests that the
north arc could be part of a large streamer flowing from the circumbinary ring
to sustain the circumstellar disks. According to the previous studies, the
circumstellar disk around GG Tau Aa has enough mass and can sustain itself for
a duration sufficient for planet formation; thus, our study indicates that
planets can form within close (separation 100 AU) young binary
systems.Comment: Accepted for publication in AJ, 12 pages, 5 figure
Comparative proteomics using 2-D gel electrophoresis and mass spectrometry as tools to dissect stimulons and regulons in bacteria with sequenced or partially sequenced genomes
We propose two-dimensional gel electrophoresis (2-DE) and mass spectrometry to define the protein components of regulons and stimulons in bacteria, including those organisms where genome sequencing is still in progress. The basic 2-DE protocol allows high resolution and reproducibility and enables the direct comparison of hundreds or even thousands of proteins simultaneously. To identify proteins that comprise stimulons and regulons, peptide mass fingerprint (PMF) with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS) analysis is the first option and, if results from this tool are insufficient, complementary data obtained with electrospray ionization tandem-MS (ESI-MS/MS) may permit successful protein identification. ESI-MS/MS and MALDI-TOF-MS provide complementary data sets, and so a more comprehensive coverage of a proteome can be obtained using both techniques with the same sample, especially when few sequenced proteins of a particular organism exist or genome sequencing is still in progress
Skeletal muscle and performance adaptations to high-intensity training in elite male soccer players: speed endurance runs versus small-sided game training.
PURPOSE: To examine the skeletal muscle and performance responses across two different exercise training modalities which are highly applied in soccer training. METHODS: Using an RCT design, 39 well-trained male soccer players were randomized into either a speed endurance training (SET; nâ=â21) or a small-sided game group (SSG; nâ=â18). Over 4 weeks, thrice weekly, SET performed 6-10âĂâ30-s all-out runs with 3-min recovery, while SSG completed 2âĂâ7-9-min small-sided games with 2-min recovery. Muscle biopsies were obtained from m. vastus lateralis pre and post intervention and were subsequently analysed for metabolic enzyme activity and muscle protein expression. Moreover, the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) was performed. RESULTS: Muscle CS maximal activity increased (Pâ<â0.05) by 18% in SET only, demonstrating larger (Pâ<â0.05) improvement than SSG, while HAD activity increased (Pâ<â0.05) by 24% in both groups. Na(+)-K(+) ATPase α1 subunit protein expression increased (Pâ<â0.05) in SET and SSG (19 and 37%, respectively), while MCT4 protein expression rose (Pâ<â0.05) by 30 and 61% in SET and SSG, respectively. SOD2 protein expression increased (Pâ<â0.05) by 28 and 37% in SET and SSG, respectively, while GLUT-4 protein expression increased (Pâ<â0.05) by 40% in SSG only. Finally, SET displayed 39% greater improvement (Pâ<â0.05) in Yo-Yo IR2 performance than SSG. CONCLUSION: Speed endurance training improved muscle oxidative capacity and exercise performance more pronouncedly than small-sided game training, but comparable responses were in muscle ion transporters and antioxidative capacity in well-trained male soccer players
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