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Minh-Trung Duong,Yon-Do Chun,Pil-Wan Han,Byoung-Gun Park,Deok-Je Bang,Jin-Kyu Lee 한국자기학회 2017 Journal of Magnetics Vol.22 No.3
This paper deals with the design of an electromagnetic energy harvesting generator for the suspension system of a sport utility vehicle. The proposed generator is composed of a single coreless type permanent magnet layer, which increases flux density across the coil windings and eliminates flux leakage by using the Halbach PM array, thus improving the machine’s performance, including flux linkage and output power. The goal of the system is to regenerate energy from the kinetic energy of the suspension system of the sport utility vehicle. The proposed generator physically combines electrical and mechanical components, in which permanent magnets, coil windings, and back iron are attached to the body of the shock absorber. The design’s performance was investigated using the finite element method (FEM) and validated by comparison with experimental data.
Thermal Analysis of a High Speed Induction Motor Considering Harmonic Loss Distribution
Minh-Trung Duong,Yon-Do Chun,Byoung-Gun Park,Dong-Jun Kim,Jae-Hak Choi,Pil-Wan Han 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.4
In this paper, a thermal analysis of a high speed induction motor with a PWM voltage source was performed by considering harmonic loss components. The electromagnetic analysis of the high speed induction motor was conducted using the time-varying finite element method, and its thermal characteristics were carried out using the lump-circuit method. Harmonic losses from tests in the high frequency region were divided into core loss and conductor loss components using various ratios, in order to determine the loss distributions for the thermal analysis. The results from both the calculations and experiment were validated using a high speed induction motor prototype operating at 20,000rpm.
Minh-Trung Duong,Yon-Do Chun 한국자기학회 2018 Journal of Magnetics Vol.23 No.3
To harvest the kinetic energy from the vehicle suspension system, a tubular generator, which is composed of a single permanent magnet layer coreless model, was proposed in the previous study. Despite the excessive volume of the generator, both output power and power density are significantly lower than other conventional machines. This paper examines different designs of the tubular generator with the goal to enhance the performance, including a double permanent magnet layers coreless model and a cored model. By using a commercial finite element method (FEM) software, two proposed generators are theoretically analyzed and compared with the conventional generator. Analyzed results reveal that under the same operating conditions, the cored model can regenerate the largest amount of the power density. These results indicate that cored model can be considered as a promising candidate for the application to the electromagnetic shock absorber in sport utility vehicle (SUV).
Thermal Analysis of a High Speed Induction Motor Considering Harmonic Loss Distribution
Duong, Minh-Trung,Chun, Yon-Do,Park, Byoung-Gun,Kim, Dong-Jun,Choi, Jae-Hak,Han, Pil-Wan The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.8 No.1
In this paper, a thermal analysis of a high speed induction motor with a PWM voltage source was performed by considering harmonic loss components. The electromagnetic analysis of the high speed induction motor was conducted using the time-varying finite element method, and its thermal characteristics were carried out using the lump-circuit method. Harmonic losses from tests in the high frequency region were divided into core loss and conductor loss components using various ratios, in order to determine the loss distributions for the thermal analysis. The results from both the calculations and experiment were validated using a high speed induction motor prototype operating at 20,000rpm.
Minh, Le Quang,Duong, Pham Luu Trung,Goncalves, Jorge,Kwok, Ezra,Lee, Moonyong Elsevier 2017 Journal of the Taiwan Institute of Chemical Engine Vol.78 No.-
<P><B>Abstract</B></P> <P>Uncertainties associated with estimates of model parameters are inevitable when simulating and modeling chemical processes and significantly affect safety, consistency, and decision making. Quantifying those uncertainties is essential for emulating the actual system behaviors because they can change the management recommendations that are drawn from the model. The use of conventional approaches for uncertainty quantification (<I>e.g</I>., Monte-Carlo and standard polynomial chaos methods) is computationally expensive for complex systems with a large/moderate number of uncertainties. This paper develops a two-stage approach to quantify the uncertainty of complex chemical processes with a moderate/large number of uncertainties (greater than 5). The first stage applies a multiplicative dimensional reduction method to approximate the variance-based global sensitivity measures (Sobol's method), and to simplify the model for the uncertainty quantification stage. The second stage uses the generalized polynomial chaos approach to quantify uncertainty of the simplified model from the first stage. A rigorous simulation illustrates the proposed approach using an interface between MATLAB and HYSYS for three complex chemical processes. The proposed method was compared with conventional approaches, such as the Quasi Monte-Carlo sampling-based method and standard polynomial chaos-based method. The results revealed the clear advantage of the proposed approach in terms of the computational efforts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A two-stage approach of M-DRM and gPC proposed to UQ and SA. </LI> <LI> Sobol's indices detect non-influential inputs with little computational burden. </LI> <LI> The proposed method was compared with conventional gPC/QMC/MC methods. </LI> <LI> The computational cost was reduced by 10–100 times in comparison with the QMC method. </LI> <LI> The proposed method addresses global SA with UQ with large number of uncertain parameters. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Minh, Le Quang,Duong, Pham Luu Trung,Lee, Moonyong American Chemical Society 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.14
<P>This study presents a global sensitivity analysis to simplify a surrogate-model-based uncertainty quantification of a crude distillation unit with a large number of uncertainties. To overcome the computational limitation of a conventional surrogate model-based approach where the number of simulations required grows exponentially as the input dimension increases, a novel two-stage approach was proposed in this study: in the first stage, a multiplicative dimensional reduction method is applied to identify factors that exert the highest influence on the model outputs. In the second stage, the Gaussian process regression is exploited for uncertainty quantification from the simplified model derived in the first stage. As a result, the computational efforts for uncertainty quantification were significantly reduced (approximately more than 95%) compared to the conventional Quasi Monte Carlo, while the predicted density functions by the proposed method closely matched with those from the Quasi Monte Carlo. The proposed two-stage approach was executed for sensitivity analysis and uncertainty quantification of a crude distillation unit by an interface between MATLAB and HYSYS. The economic revenue and the operating cost per unit of crude oil processed were selected as the output of interests for the crude distillation unit. The global sensitivity analysis result showed that the flow rates of crude oil and naphtha products are critical for both the economic revenue and the operating cost.</P> [FIG OMISSION]</BR>
Le, Minh Tam,Nguyen, Thi Tam An,Nguyen, Thi Thai Thanh,Nguyen, Van Trung,Le, Dinh Duong,Nguyen, Vu Quoc Huy,Cao, Ngoc Thanh,Aints, Alar,Salumets, Andres The Korean Society for Reproductive Medicine 2018 Clinical and Experimental Reproductive Medicine Vol.45 No.3
Objective: In frozen and thawed embryos, the zona pellucida (ZP) can be damaged due to hardening. Laser-assisted hatching (LAH) of embryos can increase the pregnancy rate. This study compared thinning and drilling of the ZP before frozen embryo transfer (FET). Methods: Patients were randomly allocated into two groups for LAH using thinning or drilling on day 2 after thawing. Twenty-five percent of the ZP circumference and 50% of the ZP thickness was removed in the thinning group, and a hole $40{\mu}m$ in diameter was made in the drilling group. Results: A total of 171 in vitro fertilization/intracytoplasmic sperm injection FET cycles, including 85 cycles with drilling LAH and 86 cycles with thinning LAH, were carried out. The thinning group had a similar ${\beta}$-human chorionic gonadotropin-positive rate (38.4% vs. 29.4%), implantation rate (16.5% vs. 14.4%), clinical pregnancy rate (36.0% vs. 25.9%), miscarriage rate (5.8% vs. 2.4%), ongoing pregnancy rate (30.2% vs. 23.5%), and multiple pregnancy rate (7.0% vs. 10.6%) to the drilling LAH group. There were no significant differences in pregnancy outcomes between subgroups defined based on age (older or younger than 35 years) or ZP thickness (greater or less than $17{\mu}m$) according to the LAH method. Conclusion: The present study demonstrated that partial ZP thinning or drilling resulted in similar outcomes in implantation and pregnancy rates using thawed embryos, irrespective of women's age or ZP thickness.