. Although in heavy-ion therapy, the quantum molecular dynamics (QMD) model is one of the most fundamental physics models providing an accurate daughter-ion production yield in the final state, there ...are still non-negligible differences with the experimental results. The aim of this study is to improve fragment production in water phantoms by developing a more accurate QMD model in Geant4.
. A QMD model was developed by implementing modern Skyrme interaction parameter sets, as well as by incorporating with an ad hoc
-cluster model in the initial nuclear state. Two adjusting parameters were selected that can significantly affect the fragment productions in the QMD model: the radius to discriminate a cluster to which nucleons belong after the nucleus-nucleus reaction, denoted by
, and the squared standard deviation of the Gaussian packet, denoted by
. Squared Mahalanobis's distance of fragment yields and angular distributions with 1, 2, and the higher atomic number for the produced fragments were employed as objective functions, and multi-objective optimization (MOO), which make it possible to compare quantitatively the simulated production yields with the reference experimental data, was performed.
. The MOO analysis showed that the QMD model with modern Skyrme parameters coupled with the proposed
-cluster model, denoted as SkM
, can drastically improve light fragments yields in water. In addition, the proposed model reproduced the kinetic energy distribution of the fragments accurately. The optimized
in SkM
was confirmed to be realistic by the charge radii analysis in the ground state formation.
. The proposed framework using MOO was demonstrated to be very useful in judging the superiority of the proposed nuclear model. The optimized QMD model is expected to improve the accuracy of heavy-ion therapy dosimetry.
Measurement of wheel–rail contact forces is very important, but it is not executed so often because of its difficulties. A new measuring method introduced in this paper can measure such contact ...forces without special wheelsets equipped with strain gauges and slip rings or telemeters. In this method the lateral contact force is measured from the lateral distortion of wheel measured directly by several non-contact gap sensors. Normal and longitudinal contact forces are also measured from the deflection of spring or the strain of parts of the bogies except wheelsets. According to the results of full-size bogie stand tests and train running tests, it is verified that the new method has sufficient practicability of monitoring the contact forces on commercial lines.
By using non-contact gap sensors equipped on non-rotating parts of a bogie, a new measuring method of wheel/rail contact forces has been developed. The developed system has been verified to have ...sufficient durability for continuous measurement on in-service trains and sufficient practical accuracy after various stand tests and train running tests. After a long-period of continuous measurement on a commercial subway line, some important characteristics of wheel/rail contact mechanics were found by the analysis of measured data. Numerical simulations of curving with a full vehicle model using multi-body dynamics software were carried out, and according to the comparison with measured data, simulation results agree well with measured data in the steady-state values of derailment coefficients considering friction coefficient.
A new measuring method introduced in this paper can measure contact forces between wheel and rail without special wheel-set with slip rings or telemeters. In this method the lateral contact force is ...measured from the lateral distortion of wheel measured directly by several non-contact gap sensors. Normal and longitudinal contact forces are also measured from the deflection of spring or the strain of parts of the bogies except special wheel-set. This new method, unlike the conventional method, is able to store the data everyday on every curve of commercial lines, which change according to friction coefficient and train running speed and so on. In this paper the authors describe the new measuring method without strain-gauge-equipped wheel-set, estimations of comparing the new method and the conventional method, and data analysis of measurements by commercial service trains. Practicable use of this new method enables us to easily obtain the statistical data of derailment coefficients with an on-board measuring method. Statistically analyzing the variation of rail-lubrication conditions and characteristics of wheel-rail contact force on every curve with this new system can help to improve track conditions for maintenance.
The ability of gene transfer with the pore-forming subunit of the human maxi-K channel (hSlo) to ameliorate the decline in erectile capacity commensurate with 12-24 wk of streptozotocin ...(STZ)-diabetes was examined in 181 Fischer-344 rats. A 2-mo period of STZ-diabetes was induced before gene transfer, and erectile capacity was evaluated by measuring the intracavernous pressure response (ICP) to cavernous nerve (CN) stimulation (ranging from 0.5 to 10 mA). In the first series of experiments, ANOVA revealed increased CN-stimulated ICP responses at 1 and 2 mo postinjection of 100 microg pcDNA-hSlo compared with control values. A second series of experiments further examined the dose dependence and duration of gene transfer. The ICP response to submaximal (0.5 mA) and maximal (10 mA) nerve stimulation was evaluated 3 or 4 mo postinjection of a single dose of pcDNA-hSlo ranging from 10 to 1,000 microg. ANOVA again revealed that hSlo overexpression was associated with increased CN-stimulated ICP responses compared with responses in corresponding control animals. Histological studies revealed no immune response to the presence of hSlo. PCR analysis documented that expression of both plasmid and transcript were largely confined to the corporal tissue. In the third series of pharmacological experiments, hSlo gene transfer in vivo was associated with iberiotoxin-sensitive relaxation responses to sodium nitroprusside in corporal tissue strips in vitro. The latter data indicate that gene transfer produces functional maxi-K channels that participate in the modulation of corporal smooth muscle cell tone. Taken together, these observations suggest a fundamental diabetes-related change in corporal myocyte maxi-K channel regulation, expression, or function that may be corrected by expression of recombinant hSlo.
This paper presents the curving performance of railway vehicles with air suspensions. Air suspensions sometimes cause reduction of wheel load at transition curve. In previous studies it was found ...that the air suspensions have non-linear characteristics at low speed and that the performance is influenced by the initial condition, the entrance transition curve condition and so on, by computer simulation and experiments using one-car-modeled test bench. Proposed new concept devices have functions to make the link rod of air suspension systems extend or shorten. These proposed control methods were examined by the experiments using one-car-modeled test bench and simulations. In this study, a new type of Leveling Valve (LV) with two-step characteristic was proposed to enhance the control performance to prevent Wheel Load reduction, and at the same time, the control device was sure of fail-safe. Wheel Load reduction of 1st axle outside was prevented further more experimentally, and derailment coefficient reduction effect was convinced by full car tight curve passing simulation using multi-body dynamics analysis software.
Controlling the friction between wheel and rail is direct and very effective measures to improve the curving performances of railway trucks, because the curving performances of truck depend much on ...friction characteristics. Authors have proposed a method, “friction control”, which utilizes friction modifier (KELTRACKTM HPF) with onboard spraying system. With the method, not only friction coefficient, but also friction characteristics are able to he controlled as expected. In this paper, results of fundamental experiments are reported which play an important role to realize the new method.
This paper presents the curving performance of railway vehicles with air suspensions. Air suspensions sometimes cause reduction of wheel load at transition curve, so it is very important to evaluate ...the performance on transition curve and to control air suspensions properly. In previous study it was found that the air suspensions have non-linear characteristics at low speed and that the performance is influenced by the initial condition, the entrance transition curve condition and so on by computer simulation and experiments using one-car-modeled test bench. In this study, the new concept devices, which have functions to make the link rod of air suspension systems extend or shorten, were proposed. The control strategies to compensate the difference of initial condition at the curve entry and prevent the reduction of wheel load at exit transition curve at low speed were also proposed. These proposed control methods were examined by the experiments using one-car-modeled test bench and simulations. As the result, expected performance was obtained so that reduction of wheel load was restraint very much.
The authors propose a new concept of the active steering bogie, which has simple mechanism and high curving performance. Active-bogie-steering bogie has the steering mechanism only between car-body ...and bogie frame and no mechanism in wheelsets. On curved track, the bogie frames are steered towards radial steering direction by actuators according to active control law. In this paper, we show that the lateral contact force of the leading-outside wheel can be reduced to zero even on very sharp curve by this mechanism. Validity tests were carried out by using a full-size test bogie on the rolling test stand, which can simulate curve-running condition. Bogie parameters and steering actuator characteristics are identified in order to compare the experimental results with multibody dynamics simulation. After these stand tests and simulation, we successfully verified the effectiveness of the proposed bogie mechanism and control.
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