Development Of Fuel-Flexible Gas Turbine Combustor

LectureGrowing global energy demands are motivating the gas turbine industry to seek fuel-flexible gas turbines capable of burning a wide variety of fuels as a means of increasing energy supply stability and security. These fuel-flexible gas turbines require diluent-free (“dry”), low nitrogen oxide (NOx) and flashback-resistant combustors for various fuels in order to achieve low NOx emissions and high plant efficiency for low carbon dioxide (CO2) emissions. This paper describes the development of a state-of-the-art dry low-NOx and flashback-resistant combustor for fuel-flexible gas turbines. This advanced combustor consists of multiple fuel nozzles and multiple air holes. One fuel nozzle and one air hole are installed coaxially to give one key element, and a cluster of key elements constitutes one burner, which forms one flame. Multiple cluster burners constitute a can combustor, and several can combustors are installed on a gas turbine. In this paper, the burner is called a “cluster burner,” and the combustor is called a “multi-cluster combustor.” The essence of the burner concept is the integration of two key technologies: low-NOx combustion due to the enhancement of fuel-air mixing; and flashback-resistant combustion due to short premixing sections, air-stream-surrounded fuel jets and lifted flames. The development approach of the multi-cluster combustor consists of three steps: burner development; combustor development; and feasibility demonstration for practical plants. The first step optimizes burner configurations by fundamental research at atmospheric pressure. The second step optimizes combustor configurations by single-can combustor testing at medium to high pressures. The third step demonstrates the feasibility of the combustor by field testing with real gas turbines. This paper describes the development work in each step of the multi-cluster combustor developed particularly for hydrogen content syngas fuels in a coal-based integrated gasification combined cycle (IGCC), and the field test in an IGCC pilot plant demonstrates the feasibility of the combustor for practical plants. This paper also describes applications of this combustion technology to expand fuel flexibility

The Effect of Prior Knowledge of Color on Behavioral Responses and Event-Related Potentials During Go/No-go Task

In daily life, the meaning of color plays an important role in execution and inhibition of a motor response. For example, the symbolism of traffic light can help pedestrians and drivers to control their behavior, with the color green/blue meaning go and red meaning stop. However, we don’t always stop with a red light and sometimes start a movement with it in such a situation as drivers start pressing the brake pedal when a traffic light turns red. In this regard, we investigated how the prior knowledge of traffic light signals impacts reaction times (RTs) and event-related potentials (ERPs) in a Go/No-go task. We set up Blue Go/Red No-go and Red Go/Blue No-go tasks with three different go signal (Go) probabilities (30, 50, and 70%), resulting in six different conditions. The participants were told which color to respond (Blue or Red) just before each condition session but didn’t know the Go probability. Neural responses to Go and No-go signals were recorded at Fz, Cz, and Oz (international 10–20 system). We computed RTs for Go signal and N2 and P3 amplitudes from the ERP data. We found that RT was faster when responding to blue than red light signal and also was slower with lower Go probability. Overall, N2 amplitude was larger in Red Go than Blue Go trial and in Red No-go than Blue No-go trial. Furthermore, P3 amplitude was larger in Red No-go than Blue No-go trial. Our findings of RT and N2 amplitude for Go ERPs could indicate the presence of Stroop-like interference, that is a conflict between prior knowledge about traffic light signals and the meaning of presented signal. Meanwhile, the larger N2 and P3 amplitudes in Red No-go trial as compared to Blue No-go trial may be due to years of experience in stopping an action in response to a red signal and/or attention. This study provides the better understanding of the effect of prior knowledge of color on behavioral responses and its underlying neural mechanisms

Cutaneous information processing differs with load type during isometric finger abduction

博士(保健学)Doctor of Philosophy in Health Science広島大学Hiroshima Universit

Per-rectal Portal Scintigraphy with Technetium-99m Pertechnetate for Esophageal Varices

Per-rectal portal scintigraphy is a non-invasive method in which a radioisotope is used for imaging of the portal collaterals. Per-rectal portal scintigraphy with 99m-technetium pertechnetate (99mTcO4-) was performed in 42 subjects to evaluate the portal hemodynamics. Ten healthy controls, 13 cases of liver cirrhosis without esophageal varices, 15 cases of liver cirrhosis with esophageal varices, and 4 cases of portal systemic shunt were included in this study. Moreover, in 4 patients who underwent transabdominal esophageal transection, per-rectal portal scintigraphy was repeated one month postoperatively. Portosystemic shunt index was calculated by the following equation. Shunt Index (%) = (99mTcO4 Counts of Heart/99mTcO4 Counts of Liver and Heart) × 100. The results, expressed as shunt index (SI) were: 8.8 ± 5.2 in controls, 21.2 ± 8.0 in cirrhotic patients without esophageal varices, 31.0 ± 18.5 in cirrhotic patients with esophageal varices, and 49.0 ± 6.9 in patients with portosystemic shunt. After transabdominal esophageal transection, the shunt indices were decreased in all four cases. Morphological improvements of the esophageal varices were also observed. These results suggest that the shunt index measured by perrectal portal scintigraphy may be useful for assessment of portal collaterals, especially for patients with esophageal varices

Event-related potentials evoked by skin puncture reflect activation of Aβ fibers: comparison with intraepidermal and transcutaneous electrical stimulations

Background Recently, event-related potentials (ERPs) evoked by skin puncture, commonly used for blood sampling, have received attention as a pain assessment tool in neonates. However, their latency appears to be far shorter than the latency of ERPs evoked by intraepidermal electrical stimulation (IES), which selectively activates nociceptive Aδ and C fibers. To clarify this important issue, we examined whether ERPs evoked by skin puncture appropriately reflect central nociceptive processing, as is the case with IES. Methods In Experiment 1, we recorded evoked potentials to the click sound produced by a lance device (click-only), lance stimulation with the click sound (click+lance), or lance stimulation with white noise (WN+lance) in eight healthy adults to investigate the effect of the click sound on the ERP evoked by skin puncture. In Experiment 2, we tested 18 heathy adults and recorded evoked potentials to shallow lance stimulation (SL) with a blade that did not reach the dermis (0.1 mm insertion depth); normal lance stimulation (CL) (1 mm depth); transcutaneous electrical stimulation (ES), which mainly activates Aβ fibers; and IES, which selectively activates Aδ fibers when low stimulation current intensities are applied. White noise was continuously presented during the experiments. The stimulations were applied to the hand dorsum. In the SL, the lance device did not touch the skin and the blade was inserted to a depth of 0.1 mm into the epidermis, where the free nerve endings of Aδ fibers are located, which minimized the tactile sensation caused by the device touching the skin and the activation of Aβ fibers by the blade reaching the dermis. In the CL, as in clinical use, the lance device touched the skin and the blade reached a depth of 1 mm from the skin surface, i.e., the depth of the dermis at which the Aβ fibers are located. Results The ERP N2 latencies for click-only (122 ± 2.9 ms) and click+lance (121 ± 6.5 ms) were significantly shorter than that for WN+lance (154 ± 7.1 ms). The ERP P2 latency for click-only (191 ± 11.3 ms) was significantly shorter than those for click+lance (249 ± 18.6 ms) and WN+lance (253 ± 11.2 ms). This suggests that the click sound shortens the N2 latency of the ERP evoked by skin puncture. The ERP N2 latencies for SL, CL, ES, and IES were 146 ± 8.3, 149 ± 9.9, 148 ± 13.1, and 197 ± 21.2 ms, respectively. The ERP P2 latencies were 250 ± 18.2, 251 ± 14.1, 237 ± 26.3, and 294 ± 30.0 ms, respectively. The ERP latency for SL was significantly shorter than that for IES and was similar to that for ES. This suggests that the penetration force generated by the blade of the lance device activates the Aβ fibers, consequently shortening the ERP latency. Conclusions Lance ERP may reflect the activation of Aβ fibers rather than Aδ fibers. A pain index that correctly and reliably reflects nociceptive processing must be developed to improve pain assessment and management in neonates

Higher synchronization stability with piano experience: relationship with finger and presentation modality

Abstract Background Synchronous finger tapping to external sensory stimuli is more stable for audiovisual combined stimuli than sole auditory or visual stimuli. In addition, piano players are superior in synchronous tapping and manipulating the ring and little fingers as compared to inexperienced individuals. However, it is currently unknown whether the ability to synchronize to external sensory stimuli with the ring finger is at the level of the index finger in piano players. The aim of this study was to compare the effect of piano experience on synchronization stability between the index and ring fingers using auditory, visual, and audiovisual combined stimuli. Methods Thirteen piano players and thirteen novices participated in this study. They were instructed to tap with their index or ring finger synchronously to auditory, visual, and audiovisual combined stimuli. The stimuli were presented from an electronic metronome at 1 Hz, and the tapping was performed 30 times in each condition. We analyzed standard deviation of intervals between the stimulus onset and the tap onset as synchronization stability. Results Synchronization stability for visual stimuli was lower during ring than index finger tapping in novices; however, this decline was absent in piano players. Also, piano players showed the higher synchronization stability for audiovisual combined stimuli than sole visual and auditory stimuli when tapping with the index finger. On the other hand, in novices, synchronization stability was higher for audiovisual combined stimuli than only visual stimuli. Conclusions These findings suggest that improvements of both sensorimotor processing and finger motor control by piano practice would contribute to superior synchronization stability

Transient Modulation of Working Memory Performance and Event-Related Potentials by Transcranial Static Magnetic Field Stimulation over the Dorsolateral Prefrontal Cortex

Transcranial static magnetic field stimulation (tSMS) can modulate human cortical excitability and behavior. To better understand the neuromodulatory effect of tSMS, this study investigates whether tSMS applied over the left dorsolateral prefrontal cortex (DLPFC) modulates working memory (WM) performance and its associated event-related potentials (ERPs). Thirteen healthy participants received tSMS or sham stimulation over the left DLPFC for 26 min on different days. The participants performed a 2-back version of the n-back task before, during (20 min after the start of stimulation), immediately after, and 15 min after the stimulation. We examine reaction time for correct responses, d-prime reflecting WM performance, and the N2 and P3 components of ERPs. Our results show that there was no effect of tSMS on reaction time. The d-prime was reduced, and the N2 latency was prolonged immediately after tSMS. These findings indicate that tSMS over the left DLPFC affects WM performance and its associated electrophysiological signals, which can be considered an important step toward a greater understanding of tSMS and its use in studies of higher-order cognitive processes