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We developed a prototype of a high-Tc superconducting (HTS) linear synchronous motor (LSM) and evaluated its operational performances to obtain the preliminary design data for a test vehicle having a speed of 518.4 km/h. The HTS electromagnet was fabricated using a non-insulated (NI) GdBCO HTS coil, which was designed to produce a magnetomotive force of 300 kA-turns at a cooling temperature of 20 K. A two-stage Gifford-McMahon cryocooler was used to cool the electromagnet. The prototype was tested up to 2.7 kN sufficient to the required thrust of the test vehicle. The thrust characteristics shown by changing the operating conditions were also consistent with the simulation results. The HTS electromagnet was successfully operated during the test, and there was no fault in the NI HTS coils. Finally, we confirmed the design feasibility of HTS LSM for a test vehicle.

Motivated by the growing interest in the Hyperloop system, we have researched a new mode of transportation that runs inside a vacuum tube at more than 1,000 km/h. A 2G high-temperature superconducting (HTS) magnet with a detachable cryocooling system has been developed to thrust and levitate the capsule train efficiently; it also reduces its weight. To compensate for performance losses due to increased operating temperature, the HTS coil shape of the on-board superconducting magnet is topologically optimized with respect to cost and performance. With a number of linear constraints converted from nonlinear superconductivity conditions, many linear topology optimization problems are solved, and then the most preferred design is determined by considering its shape, cost, and performance.

Hyperloop allows for improved transportation efficiency at higher speeds and a lower power consumption. Various magnetic levitation technologies in existing high-speed maglev trains are being considered to overcome speed limitations for the development of Hyperloop, which are driven inside vacuum tubes at 1,200 km/h; and superconducting (SC) electrodynamic suspension (EDS) can provide numerous advantages to Hyperloop. such as enabling stable levitation in high-speed driving without control, and increasing the levitation air gap. However, the analysis of the EDS system requires the electromagnetic transient analysis of complex three-dimensional (3D) features, and its computational load generally limits the use of numerical methods, such as the 3D finite element method (FEM) or dynamic circuit theory; This paper presents a novel model that can rapidly and accurately calculate the frequency-dependent equivalent inductance; and it can model the EDS system with the decoupled resistance-inductance (RL) equations of levitation coils. As a design example, the levitation coils of the SC-EDS were designed and analyzed for the Hyperloop, and the results were compared with those of the FEM results to validate the model. In addition, the model was experimentally validated by measuring currents induced by moving pods.

As a maglev levitates with a small air gap and runs very fast, securing the levitation system's stability is crucial. Thus, the high-performance decoupling control between the propulsion control system and the levitation system is of critical importance. The study described in this paper focuses on a high-performance position estimator that minimizes the dynamic coupling between the levitation system and propulsion system in a maglev's propulsion control system using a long-stator linear synchronous motor. To that end, a position estimator using a Kalman filter was designed. Then the stability of the designed filter and its characteristics and problems that result from the change in the measurement covariance value were identified through a stability analysis of the Kalman filter. Moreover, in an attempt to improve it, a Kalman filter with a data rejection filter was proposed. Afterward, to verify the performance of the proposed position estimator, a maglev train model was fabricated and for each Kalman filter measurement covariance value, the dynamic coupling between the propulsion control system and the levitation system was identified through the test. For the Kalman filter using a data rejection filter, it was confirmed that the propulsion control system could minimize the influence on the levitation system when an inaccurate position of the vehicle is renewed.

This study addresses the Hyperloop characterized by a capsule-type vehicle, superconducting electrodynamic suspension (SC-EDS) levitation, and driving in a near-vacuum tube. Because the Hyperloop is different from conventional transportation, various considerations are required in the vehicle-design stage. Particularly, pre-investigation of the vehicle dynamic characteristics is essential because of the close relationship among the vehicle design parameters, such as size, weight, and suspensions. Accordingly, a 1/10 scale Hyperloop vehicle system model, enabling the analysis of dynamic motions in the vertical and lateral directions, was developed. The reduced-scale model is composed of bogies operated by Stewart platforms, secondary suspension units, and a car body. To realize the bogie motion, an operation algorithm reflecting the external disturbance, SC-EDS levitation, and interaction between the bogie and car body, was applied to the Stewart platform. Flexible rubber springs were used in the secondary suspension unit to enable dynamic characteristic analysis of the vertical and lateral motion. Results of the verification tests were compared with simulation results to examine the fitness of the developed model. The results showed that the developed reduced-scale model could successfully represent the complete dynamic characteristics, owing to the enhanced precision of the Stewart platform and the secondary suspension allowing biaxial motions.

Hyperloop is a new, alternative, very high-speed mode of transport wherein Hyperloop pods (or capsules) transport cargo and passengers at very high speeds in a near-vacuum tube. Such high-speed operations, however, cause a large aerodynamic drag. This study investigates the effects of pod speed, blockage ratio (BR), tube pressure, and pod length on the drag and drag coefficient of a Hyperloop. To study the compressibility of air when the pod is operating in a tube, the effect of pressure waves in terms of propagation speed and magnitude are investigated based on normal shockwave theories. To represent the pod motion and propagation of pressure waves, unsteady simulation using the moving-mesh method was applied under the sheer stress transport k&ndash, &omega, turbulence model. Numerical simulations were performed for different pod speeds from 100 to 350 m/s. The results indicate that the drag coefficient increases with increase in BR, pod speed, and pod length. In the Hyperloop system, the compression wave propagation speed is much higher than the speed of sound and the expansion wave propagation speed that experiences values around the speed of sound.

There are two major obstacles that prevent a conventional train from achieving high speed: the limitation of wheel–rail adhesion and the increase of instability in the wheel–rail running dynamics. To overcome these problems, a new hybrid train model is introduced in this study. This train utilizes a superconducting linear synchronous motor (SC-LSM), instead of a traction motor, for propulsion; therefore, this train does not have the limitation of adhesion between the wheel and the rail. Using an SC-LSM also improves the stability of the train during high-speed operations. The magnetic stiffness between the train and the guideway is additionally generated by using the SC-LSM, which is favorable for the running stability at a high speed. This study focuses on the magnetic stiffness and its effect on the running stability in the proposed hybrid train model. First, the magnetic stiffness in the SC-LSM is investigated both theoretically and experimentally. Then, a train dynamic model including the magnetic stiffness is developed and the effect of magnetic stiffness on the running stability is analyzed through various simulations.

In this study, numerical simulations were conducted at various pod speeds ( v p o d = 100–350 m/s) using an unsteady, compressible solver with the Reynolds-averaged Navier–Stokes model to analyze the aerodynamic characteristics and pressure wave behavior in the Hyperloop system. Furthermore, the aerodynamic drag and pressure wave behavior were theoretically predicted based on quasi-one-dimensional assumptions. The flow around the pod is classified into three regimes according to the pod speed based on the compressible flow phenomena. In regime 1 ( v p o d = 100–170 m/s), the compression waves develop into normal shock waves even without the occurrence of choking at the throat. In regime 2 ( v p o d = 180–230 m/s), choking occurs at the throat and an oblique shock wave appears within the pod tail section. In regime 3 ( v p o d = 240–350 m/s), a trailing shock wave propagates at the end of the oblique shock wave. Due to fully accelerated flow in this regime, the Mach number of the flow behind the pod in a pod-fixed coordinates remains constant as 2.1, regardless of the pod speed. This constant Mach number causes the drag coefficient to decrease while the pod speed increases. Although non-isentropic conditions such as the formation of a boundary layer and flow separation cause variation between the theoretical prediction and simulation results, the predicted properties of the pressure waves and the aerodynamic drag of the pod concur with the simulation results. Because the boundary layer along the pod is thinner at a higher pod speed, the difference between the theoretical and simulation values of the leading shock pressure decreases from 9.71% to 2.83% and that of the leading shock speed decreases from 4.39% to 1.30% as the pod speed increases from 180 to 350 m/s. Additionally, the theoretically predicted drag of the pod shows good agreement with the simulation results with an error of around 6%.

A levitation system based on sidewall electrodynamic suspension (EDS) is considered for a capsule vehicle, which is a next-generation high-speed transportation system currently being studied. This levitation system does not require controlling of the gap between the guideway and the vehicle on which the superconducting electromagnet is mounted. However, when the vehicle is operated in a levitated state, the ride comfort is worse than that of the levitation system based on electromagnetic suspension (EMS), making it necessary to develop methods that can ensure good riding comfort. In addition, because the EDS system is complex and nonlinear with a combination of electromagnetics and mechanical dynamics, it is complicated to analyze the dynamic characteristics of the capsule vehicle, and the corresponding numerical analysis is time-consuming. Therefore, to easily understand the running dynamics of a capsule vehicle in the sidewall EMS system, the magnetic suspension characteristics corresponding to the primary suspension are simply modeled by considering the levitation stiffness in the vertical direction and the guidance stiffness in the lateral direction, similar to that in the case of the mechanical suspension. In this study, mathematical models of the levitation and guidance stiffnesses with respect to the speed and position of a vehicle body running at high speeds in a levitated state in the sidewall EDS system were derived for three design proposals of the levitation coil. The dynamic behavior of the vehicle based on the three design proposals was investigated by simulating a capsule vehicle model with 15 degrees of freedom.

The Hyperloop system is a new concept that allows a train to travel through a near-vacuum tunnel at transonic speeds. Aerodynamic drag is one of the most important factors in analyzing such systems. The blockage ratio (BR), pod speed/length, tube pressure, and temperature affect the aerodynamic drag, but the specific relationships between the drag and these parameters have not yet been comprehensively examined. In this study, we investigated the flow phenomena of a Hyperloop system, focusing on the effects of changes in the above parameters. Two-dimensional axisymmetric simulations were performed in a large parameter space covering various BR values (0.25, 0.36), pod lengths (10.75–86 m), pod speeds (50–350 m/s), tube pressures (~100–1000 Pa), and tube temperatures (275–325 K). As BR increased, the pressure drag was significantly affected. This is because of the smaller critical Mach number for a larger BR. As the pod length increased, the total drag and pressure drag did not change significantly, but there was a considerable influence on the friction drag. As the pod speed increased, strong shock waves occurred near the end of the pod. At this point, the flows around the pod were severely choked at both BR values, and the ratio of the pressure drag to the total drag converged to its saturation level. At tube pressures above 500 Pa, the friction drag increased significantly under the rapidly increased turbulence intensity near the pod surface. High tube temperatures increase the speed of sound, and this reduces the Mach number for the same pod speed, consequently delaying the onset of choking and reducing the aerodynamic drag. The results presented in this study are applicable to the fundamental design of the proposed Hyperloop system.

Although H-1 parvovirus is used as an antitumor agent, not much is known about the relationship between its specific tropism and oncolytic activity. We hypothesize that VP2, a major capsid protein of H-1 virus, determines H-1-specific tropism. To assess this, we constructed chimeric H-1 viruses expressing Kilham rat virus (KRV) capsid proteins, in their complete or partial forms. Chimeric H-1 viruses (CH1, CH2 and CH3) containing the whole KRV VP2 domain could not induce cytolysis in HeLa, A549 and Panc-1 cells. However, the other chimeric H-1 viruses (CH4 and CH5) expressing a partial KRV VP2 domain induced cytolysis. Additionally, the significant cytopathic effect caused by CH4 and CH5 infection in HeLa cells resulted from preferential viral amplification via DNA replication, RNA transcription and protein synthesis. Modeling of VP2 capsid protein showed that two variable regions (VRs) (VR0 and VR2) of H-1 VP2 protein protrude outward, because of the insertion of extra amino-acid residues, as compared with those of KRV VP2 protein. This might explain the precedence of H-1 VP2 protein over KRV in determining oncolytic activity in human cancer cells. Taking these results together, we propose that the VP2 protein of oncolytic H-1 parvovirus determines its specific tropism in human cancer cells.

A suspension system is one of the integral parts of a hyperloop capsule train, which is used to isolate the car-body from bogie vibration to provide a safer and comfortable service. A semi-active suspension system is one of the best candidates for its advantageous features. The performance of a semi-active suspension system relies greatly on the control strategy applied. In this article, Skyhook (SH) and mixed Skyhook-Acceleration Driven Damper (SH-ADD) controlling algorithms are adopted for a nonlinear quarter-car model of a capsule with semi-active magnetorheological damper. The nonlinear vertical dynamic response and performance of the proposed control algorithms are evaluated under MATLAB Simulink environment and hardware-in-loop-system (HILS) environment. The SH controlled semi-active suspension system performance is found to be better at the first resonance frequency and worse at the second resonance frequency than the passive MR damper, but the mixed SH-ADD controlled semi-active suspension system performs better than the passive at all frequency domains. Taking the root-mean-square (RMS) value of sprung mass vertical displacement as an evaluation criterion, the response is reduced by 58.49% with mixed SH-ADD controller and by 54.49% with the SH controller compared to the passive MR damper suspension.

Although H-1 parvovirus is used as an antitumor agent, not much is known about the relationship between its specific tropism and oncolytic activity. We hypothesize that VP2, a major capsid protein of H-1 virus, determines H-1-specific tropism. To assess this, we constructed chimeric H-1 viruses expressing Kilham rat virus (KRV) capsid proteins, in their complete or partial forms. Chimeric H-1 viruses (CH1, CH2 and CH3) containing the whole KRV VP2 domain could not induce cytolysis in HeLa, A549 and Panc-1 cells. However, the other chimeric H-1 viruses (CH4 and CH5) expressing a partial KRV VP2 domain induced cytolysis. Additionally, the significant cytopathic effect caused by CH4 and CH5 infection in HeLa cells resulted from preferential viral amplification via DNA replication, RNA transcription and protein synthesis. Modeling of VP2 capsid protein showed that two variable regions (VRs) (VR0 and VR2) of H-1 VP2 protein protrude outward, because of the insertion of extra amino-acid residues, as compared with those of KRV VP2 protein. This might explain the precedence of H-1 VP2 protein over KRV in determining oncolytic activity in human cancer cells. Taking these results together, we propose that the VP2 protein of oncolytic H-1 parvovirus determines its specific tropism in human cancer cells.

The water dispersible granule flupoxam showed over 95% of weeding effect on the annual weeds of Poaceae such as Poa annua L., Digitaria ciliaris (Rets.) Koel and broad-leaf weeds. Efficacy of treatment had been lasted over 120 days in the when it was treated from March to April while lasted over 180 days when it was treated from September to October. Because the flupoxam has a high soil absorptivity, a perfected herbicide layer is formed. This results in perfect weeding effect regardless of the presence or absence of thatch. Because the flupoxam has a different mechanism of action from the conventional herbicides such as dinitroanilines, pyridines, and carbamates, it is very effective with the alternative spray. Phytotoxicity symptoms was not observed and/or produced antocyan in new leaves in the landscape trees around the lawngrass by flupoxam treatment.

A new diagnosis equipment is designed to examine the strength of large scale bridge. It is composed of three accelerometers, radio modem, and related electronics parts. Two accelerometers with high accuracy are used for measuring the change of inclination angle of the structure base and two horizontal components of structure vibration. The third accelerometer measures a vertical component of vibration. The equipment is installed in the sidewalk of some Moscow bridges as an application. Several factors such as traffic load, wind, water wave, and etc. cause the vibration of bridge. By means of appropriate processing, the spectral characteristics of the bridge itself are determined. Several month’s test shows that the spectral characteristics remains constant if the bridge state keeps constant, and is changed by the change of the bridge state (for example, before and after repair). If the measured inclination angle of the base is increased to a particular orientation, or the spectrum of bridge is changed, it is assumed that the sagging of the structure base or deformation of its structural members might happen. Periodic or continuous monitoring of the structure state under in-service condition with the help of this diagnosis equipment makes it possible to reveal the beginning of destructive changes in structural members and to prevent the occurrence of an emergency. The study result could be applied to other large structures such as towers and buildings.

In the case of a long-stator linear drive, unlike rotative drives for which speed or position sensors are a single unit attached to the shaft, these sensors extend along the guideway. The position signals transmitted from a maglev vehicle cannot meet the need of the real-time propulsion control in the on-ground inverter power substations. In this paper the design of the propulsion inverter control system with a position estimator for driving a long-stator synchronous motor in a high-speed maglev train is proposed. The experiments have been carried out at the 150 m long guideway at the O-song test track. To investigate the performance of the position estimator, the propulsion control system with, and without, the position estimator are compared. The result confirms that the proposed strategy can meet the dynamic property needs of the propulsion inverter control system for driving long-stator linear synchronous motors.

Purpose: Post-voiding residual urine hasbeen evaluated by urethral catheterization or abdomen ultrasonography in patients with benign prostatic hyperplasia. However, urethral catheterization is invasive and abdomen ultrasonography is not cost-effective for patients with benign prostatic hyperplasia. Therefore, we wished to determine the efficacy of using transrectal ultrasonography for the evaluation of the residual urine volume. Materials and Methods: A total of 37 patients were evaluated. The mean age of the patients was 69 years, ranging from 54-84 years. The empty bladder was instilled with a random volume of saline. In addition, the bladder volume was checked by transrectal ultrasonography. Results: The total mean residual urine volume checked by transrectal ultrasonography and catheterization were different statistically. When we performed a simple linear regression of the residual urine volume determined by each method, the regression coefficient was 0.699 and the determination coefficient was 58.4%. We divided the patients into two groups one group of patients with a residual urine volume of 150ml and the other group of patients with a prostate volume of 40ml. When the residual urine volume was less than 150ml and the prostate volume was less than 40ml, each mean residual urine volume was not different statistically. The determination coefficient was more than 60% by the simple linear regression. Conclusions: We could use transrectal ultrasonography for the purpose of a residual urine volume check. Especially when the residual urine volume was less than 150ml and the prostate volume was less than 40ml, we could estimate the residual urine volume by transrectal ultrasonography more accurately. (Korean J Urol 2007;48:951-955)