184 research outputs found
Train Performance - Evaluation and Monitoring by Torque Meter Applications and Process Gas Compressor / Steam Turbine Train Fouling and Washing Mitigation
LectureThe systematic monitoring and evaluation of
turbomachinery is an important diagnostic tool in the execution
of a long-term maintenance plan as well as the prevention of
unexpected outages due to machinery breakdown. This paper
introduces the typical causes of performance deterioration in
compressors and steam turbines and the phenomena related to
their causes.
In addition, this paper also introduces how to evaluate
performance, based on site monitoring techniques are explained
by combining typical evaluation results with torque
measurement and maximum power limit control. Evaluation of
these results can determine if deterioration in performance,
caused by a change in the internal flow conditions, has
occurred.
Finally, typical results from on-line washing techniques for
compressors and steam turbines will be introduced and the
power recovery rate after on-line washing, measured by the
torque meter, will be discussed
Superwind-Driven Intense H_2 Emission in NGC 6240
We have performed a long-slit K band spectroscopic observation of the
luminous infrared galaxy NGC 6240. The peak position of the H_2 v=1-0 S(1)
emission in the slit is located ~0.3" - 0.4" north of the southern nucleus. It
is almost the midpoint between the southern nucleus and the peak position of
the ^12CO J=1-0 emission. Based on the line-ratio analyses, we suggest the
excitation mechanism of H_2 is pure thermal at most positions. In the southern
region we find the following three velocity components in the H_2 emission: the
blueshifted shell component (~-250 km s^-1 with respect to V_sys) which is
recognized as a distinct C-shape distortion in the velocity field around the
southern nucleus, the high-velocity blueshifted ``wing'' component (~-1000 km
s^-1 with respect to V_sys), and the component indicating possible line
splitting of ~500 km s^-1. The latter two components are extended to the south
from the southern nucleus. We show that the kinematic properties of these three
components can be reproduced by expanding motion of a shell-like structure
around the southern nucleus. The offset peak position of the H_2 emission can
be understood if we assume that the shell expanding to the north interacts with
the extragalactic molecular gas. At the interface between the shell and the
molecular gas concentration the cloud-crushing mechanism proposed by Cowie et
al. (1981) may work efficiently, and the intense H_2 emission is thus expected
there. All these findings lead us to propose a model that the most H_2 emission
is attributed to the shock excitation driven by the superwind activity of the
southern nucleus.Comment: 33 pages, 9 figures, accepted for publication in PAS
The Japan Monkey Centre Primates Brain Imaging Repository for comparative neuroscience: an archive of digital records including records for endangered species
Advances in magnetic resonance imaging (MRI) and computational analysis technology have enabled comparisons among various primate brains in a three-dimensional electronic format. Results from comparative studies provide information about common features across primates and species-specific features of neuroanatomy. Investigation of various species of non-human primates is important for understanding such features, but the majority of comparative MRI studies have been based on experimental primates, such as common marmoset, macaques, and chimpanzee. A major obstacle has been the lack of a database that includes non-experimental primates’ brain MRIs. To facilitate scientific discoveries in the field of comparative neuroanatomy and brain evolution, we launched a collaborative project to develop an open-resource repository of non-human primate brain images obtained using ex vivo MRI. As an initial open resource, here we release a collection of structural MRI and diffusion tensor images obtained from 12 species: pygmy marmoset, owl monkey, white-fronted capuchin, crab-eating macaque, Japanese macaque, bonnet macaque, toque macaque, Sykes’ monkey, red-tailed monkey, Schmidt’s guenon, de Brazza’s guenon, and lar gibbon. Sixteen postmortem brain samples from the 12 species, stored in the Japan Monkey Centre (JMC), were scanned using a 9.4-T MRI scanner and made available through the JMC collaborative research program (http://www.j-monkey.jp/BIR/index_e.html). The expected significant contributions of the JMC Primates Brain Imaging Repository include (1) resources for comparative neuroscience research, (2) preservation of various primate brains, including those of endangered species, in a permanent digital form, (3) resources with higher resolution for identifying neuroanatomical features, compared to previous MRI atlases, (4) resources for optimizing methods of scanning large fixed brains, and (5) references for veterinary neuroradiology. User-initiated research projects beyond these contributions are also anticipated
Treatment of Patients with Neuroblastoma with High Dose Cyclophosphamide as an Optimal Method of Administration
Visualization of nerve fibers around the carotid bifurcation with use of a 9.4 Tesla microscopic magnetic resonance diffusion tensor imaging with tractography
BACKGROUND: Precise imaging of nerves have been challenging in the head and neck region, mainly due to low spatial resolution. Here, we investigated how nerves in the head and neck region could be visualized using an ultra-high magnetic field MR system. METHODS: We used formol-carbol-fixed human cadaveric necks and obtained MR diffusion tensor images (DTIs) using a 9.4 Tesla (T) ultra-high magnetic field MR system. Afterward, we prepared tissue sections and checked the anatomic relationships between the neurons and the carotid artery in order to confirm that the visualized fibers are indeed neuron fibers. RESULTS: We were able to identify nerves, including the vagus nerve, the hypoglossal nerve, and the spinal-accessory nerve. Hematoxylin-eosin stained histological sections confirmed neuron fibers in the same anatomic position. CONCLUSION: This technique has the feasibility to be applied for a more accurate anatomic understanding, maybe even close to a histological level
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Three-Dimensional Quantitative Assessment of Ablation Margins Based on Registration of Pre- and Post-Procedural MRI and Distance Map
Purpose: Contrast-enhanced MR images are widely used to confirm the adequacy of ablation margin after liver ablation for early prediction of local recurrence. However, quantitative assessment of the ablation margin by comparing pre- and post-procedural images remains challenging. We developed and tested a novel method for three-dimensional quantitative assessment of ablation margin based on non-rigid image registration and 3D distance map. Methods: Our method was tested with pre- and post-procedural MR images acquired in 21 patients who underwent image-guided percutaneous liver ablation. The two images were co-registered using non-rigid intensity-based registration. After the tumor and ablation volumes were segmented, target volume coverage, percent of tumor coverage, and Dice Similarity Coefficient were calculated as metrics representing overall adequacy of ablation. In addition, 3D distance map around the tumor was computed and superimposed on the ablation volume to identify the area with insufficient margins. For patients with local recurrences, the follow-up images were registered to the post-procedural image. Three-D minimum distance between the recurrence and the areas with insufficient margins were quantified. Results: The percent tumor coverage for all non-recurrent cases was 100%. Five cases had tumor recurrences, and the 3D distance map revealed insufficient tumor coverage or a 0-millimeter margin. It also showed that two recurrences were remote to the insufficient margin. Conclusions: Non-rigid registration and 3D distance map allows us to quantitatively evaluate the adequacy of the ablation margin after percutaneous liver ablation. The method may be useful to predict local recurrences immediately following ablation procedure
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