1,054 research outputs found
Regional price targets appropriate for advanced coal extraction
A methodology is presented for predicting coal prices in regional markets for the target time frames 1985 and 2000 that could subsequently be used to guide the development of an advanced coal extraction system. The model constructed is a supply and demand model that focuses on underground mining since the advanced technology is expected to be developed for these reserves by the target years. Coal reserve data and the cost of operating a mine are used to obtain the minimum acceptable selling price that would induce the producer to bring the mine into production. Based on this information, market supply curves can be generated. Demand by region is calculated based on an EEA methodology that emphasizes demand by electric utilities and demand by industry. The demand and supply curves are then used to obtain the price targets. The results show a growth in the size of the markets for compliance and low sulphur coal regions. A significant rise in the real price of coal is not expected even by the year 2000. The model predicts heavy reliance on mines with thick seams, larger block size and deep overburden
R-Process Nucleosynthesis In Neutrino-Driven Winds From A Typical Neutron Star With M = 1.4 Msun
We study the effects of the outer boundary conditions in neutrino-driven
winds on the r-process nucleosynthesis. We perform numerical simulations of
hydrodynamics of neutrino-driven winds and nuclear reaction network
calculations of the r-process. As an outer boundary condition of hydrodynamic
calculations, we set a pressure upon the outermost layer of the wind, which is
approaching toward the shock wall. Varying the boundary pressure, we obtain
various asymptotic thermal temperature of expanding material in the
neutrino-driven winds for resulting nucleosynthesis. We find that the
asymptotic temperature slightly lower than those used in the previous studies
of the neutrino-driven winds can lead to a successful r-process abundance
pattern, which is in a reasonable agreement with the solar system r-process
abundance pattern even for the typical proto-neutron star mass Mns ~ 1.4 Msun.
A slightly lower asymptotic temperature reduces the charged particle reaction
rates and the resulting amount of seed elements and lead to a high
neutron-to-seed ratio for successful r-process. This is a new idea which is
different from the previous models of neutrino-driven winds from very massive
(Mns ~ 2.0 Msun) and compact (Rns ~ 10 km) neutron star to get a short
expansion time and a high entropy for a successful r-process abundance pattern.
Although such a large mass is sometimes criticized from observational facts on
a neutron star mass, we dissolve this criticism by reconsidering the boundary
condition of the wind. We also explore the relation between the boundary
condition and neutron star mass, which is related to the progenitor mass, for
successful r-process.Comment: 14 pages, 2 figure
Surface erosion and modification by highly charged ions
Analyses were conducted of various models and mechanisms of highly charged ion HCI and swift-heavy ion energy transfer into a solid target, such as hollow atom formation, charge screening, neutralization, shock wave generation, crater formation, and sputtering. A plasma model of space charge neutralization based on impact ionization of semiconductors at high electric fields was developed and applied to analyze HCI impacts on Si and W. Surface erosion of semiconductor and metal surfaces caused by HCI bombardments were studied by using a molecular dynamics simulation method, and the results were compared with experimental sputtering data
Residue gamma 153Cys is essential for the formation of the complexes A alpha gamma and B beta gamma, assembly intermediates for the A alpha B beta gamma complex and intact fibrinogen
ArticleCLINICA CHIMICA ACTA. 353(1-2): 157-164 (2005)journal articl
Moderate exercise improves cognitive performance and decreases cortical activation in the go/no-go task
Background: A lot of studies have reported that physical activity has a beneficial influence not only on physical and mental disorders but also on cognitive and brain function. Performance of a go/no-go task improves after exercise. However, few studies have compared neural activity in a go/no-go task performed before and after exercise to identify brain regions that may respond to exercise and underlie this result. Therefore, the purpose of this study was to examine the brain blood flow and compare the cortical activation pattern during a go/no-go task performed before and after exercise.Method: Fifteen healthy subjects performed a go/no-go task before and after exercise. Functional near-infrared spectroscopy (fNIRS) was used to measure oxygenated hemoglobin concentration at 44 locations over both hemispheres. The exercise was of moderate intensity, defined as 50% of peak oxygen uptake.Result: The reaction time on the go/no-go task was significantly faster after exercise than before. The oxygenated hemoglobin concentration quantified across the whole brain was lower after exercise, and this was the case for go trials and no-go trials. In go trials, the oxygenated hemoglobin concentration in dorsolateral prefrontal cortex and supplementary motor area were significantly lower after exercise.Conclusion: These results suggest that the dorsolateral prefrontal cortex and supplementary motor area had lower activity in go trials in the go/no-go task performed after exercise than in go trials in the go/no-go task performed before exercise.ArticleBAOJ Medical and nursing.1(1):002(2015)journal articl
Comparison of the Effects of Two Types of Stretching Warm Ups for Rehabilitation
This pilot study compares the effects of static therapeutic trunk stretching using an unstable flex chair, a stretching bench and a stretching stick on physical fitness with those of a general Japanese style of static stretching. The participants underwent physical fitness tests. Before and after warming up using a general Japanese style of stretching and trunk treatment stretching. Twenty-three healthy college students (age, 20.7 ± 1.2 years; height, 165.3 ± 7.6 cm; weight, 59.0 ± 9.7 kg; BMI 21.4 ± 2.3) were enrolled in this study. The physical fitness test assesses grip strength, sit-ups, eyes-closed single-leg stance, sit-and-reach flexibility, six-minute walk, and ten-meter obstacle course. The participants performed vertical jump, forward standing flexion measured using the analog flexion meter, thoracolumbar extension, horizontal flexure, deep forward bow. These results suggest that trunk stretching improves flexibility, walking ability, endurance and explosive power more effectively than the general Japanese style of stretching. Three static trunk stretches can improve flexibility, walking ability, endurance and explosive power. Trunk treatment stretching before physical activity might reduce the incidence of injury and improve the physical performance of individuals who participate in exercise, athletes and injured persons undergoing rehabilitation.ArticleBAOJ Medical and nursing.1(1):003(2015)journal articl
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