Semi-Active Reaction Force Compensation for a Linear Motor Motion Stage

Duc Canh Nguyen,안형준 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.7

Acceleration and deceleration of a mover excite unwanted vibration to the system base, causing a significant reduction of life and productivity to manufacturing equipment. The system base vibration of a linear motor motion stage can be reduced with a passive reaction force compensation (RFC) mechanism. However, the passive RFC mechanism cannot provide the capability to adjust its stiffness and damping coefficient in real-time. Therefore, resonance may occur if the frequency of the passive RFC mechanism accidentally matches with the frequency components of applied motion profile. This paper presents a semi-active RFC method for a linear motor motion stage using an additional fixed coil. The semi-active RFC mechanism can adjust damping coefficient by changing the resistor load or switching the period of the additional fixed coil. The semi-active RFC mechanism also does not require an additional amplifier or control axis. Mathematical analysis of the semi-active RFC is presented to demonstrate the adjustable damping capability by changing the load resistor. Finally, the effectiveness of the proposed semi-active RFC mechanism is verified via simulations and experiments.

Rainfall-Storage-Utilization-Discharge model for flood mitigation and water conservation

Nguyen, Duc Canh,Han, Mooyoung IWA PUBLISHING 2018 WATER SCIENCE AND TECHNOLOGY -WATER SUPPLY- Vol.18 No.4

<P>Climate change and the increase of impermeable surfaces due to urbanization have led to an increase in the frequency of flooding events. The occurrence of water shortage problems is attributed to an increased population and water pollution. Traditional methods of draining rainwater from rooftops, based on the Rainfall-Discharge (R-D) model, are challenged. By storing some of the rainfall that falls on building rooftops, flooding of nearby sewer systems can be mitigated, and the reduction of peak runoff can then calculated using the Rainfall-Storage-Discharge (R-S-D) model. By utilizing stored rainfall in or near a building, flooding can be further mitigated while conserving water, and the reduction of peak runoff and the amount of used rainwater can also be calculated using the Rainfall-Storage-Utilization-Discharge (R-S-U-D) model. The R-S-U-D model uses site-specific rainfall characteristics; thus, we take Seoul, Korea as a study case. The reduced peak flow and increased design return period for a combination of tank volume and utilization rate can be calculated and presented by a curve, which can be used in the design and operation of sewer systems. Results from the R-S-U-D model can help in designing methods to reduce the flooding risk in existing sewer systems without increasing their capacity, thus reducing expenses. Water conservation is an additional benefit.</P>

A Sustainability Assessment of the Rainwater Harvesting System for Drinking Water Supply: A Case Study of Cukhe Village, Hanoi, Vietnam

Nguyen, Duc Canh,Dao, Anh Dung,Kim, Tschung-Il,Han, Mooyoung Korean Society of Environmental Engineers 2013 Environmental Engineering Research Vol.17 No.1

In Cukhe, a village located in the outskirts of Hanoi, Vietnam, people suffer from a shortage of high-quality water due to an arsenic contaminated supply water resource. We installed catchments, filters and settled tanks in the existing rainwater harvesting facility to improve water quality, and ten portable rainwater tanks to provide good-quality drinking water to the poor households and kindergartens in the dry season. The triple bottom line considerations, as well as the environmental, economic, and social impacts of the rainwater harvesting (RWH) systems are examined. RWH is a sustainable method to obtain good-quality drinking water at low cost and with little energy expenditure. Education of the system also encourages that continuation of the system and expansion can lead into economic prosperity, as the safe drinking water can be sold to the community. Hence, RWH is a unique proposal as sustainable drinking supply water for improving the lives and health of residents in Cukhe and other sites where water supply sources are contaminated.

A Sustainability Assessment of the Rainwater Harvesting System for Drinking Water Supply

Duc Canh Nguyen,Anh Dung Dao,Tschung Il Kim,Moo Young Han 대한환경공학회 2013 Environmental Engineering Research Vol.18 No.2

In Cukhe, a village located in the outskirts of Hanoi, Vietnam, people suffer from a shortage of high-quality water due to an arsenic contaminated supply water resource. We installed catchments, filters and settled tanks in the existing rainwater harvesting facility to improve water quality, and ten portable rainwater tanks to provide good-quality drinking water to the poor households and kindergartens in the dry season. The triple bottom line considerations, as well as the environmental, economic, and social impacts of the rainwater harvesting (RWH) systems are examined. RWH is a sustainable method to obtain good-quality drinking water at low cost and with little energy expenditure. Education of the system also encourages that continuation of the system and expansion can lead into economic prosperity, as the safe drinking water can be sold to the community. Hence, RWH is a unique proposal as sustainable drinking supply water for improving the lives and health of residents in Cukhe and other sites where water supply sources are contaminated.

Dynamic Analysis and Iterative Design of a Passive Reaction Force Compensation Device for a Linear Motor Motion Stage

Nguyen, Duc Canh,Ahn, Hyeong Joon Korean Society for Precision Engineering 2014 International Journal of Precision Engineering and Vol.15 No.11

Acceleration and deceleration of a mover excites vibration of the system base so as to reduce life as well as productivity of manufacturing equipment. Vibration of the system base of a linear motor motion stage can be significantly reduced with reaction force compensation (RFC) mechanisms. However, transmitted force to the system base is minimized without considering dynamics of the system base in the previous research. In this paper, dynamic analysis of the RFC system with a movable magnet track is performed considering dynamics of its system base. Furthermore, we propose an iterative design procedure for the linear motor motion stage to minimize the vibration of the system base. First, a 5 DOF dynamic model of RFC mechanism including the system base and the mover is derived and its dynamic characteristic is investigated. In addition, dynamic responses of the linear motor motion stage to both long and short stroke motions are analyzed with simulations. Secondly, an iterative design procedure of the RFC mechanism for given input motion profiles is proposed to minimize the vibration of the system base. The proposed design procedure consists of two main steps: RFC design and the system base design. Finally, effectiveness of the proposed design is verified with simulations.

A Passive Reaction Force Compensation Mechanism with a movable additional mass

Duc Canh Nguyen,Yo Han You,Hyeong Joon Ahn 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

Semi-active Reaction Force Compensation (RFC) mechanism for a Linear Motor Motion Stage

Duc-Canh Nguyen,Hyeong-Joon Ahn 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.춘계 No.-

Rapid acceleration or deceleration of a mover transfers large reaction force to system base so that the system base vibrates in very large magnitude. This residual vibration of the system base is one of major reasons to reduce lifespan as well as quality of manufacturing equipment. Vibration of the system base of a linear motor motion stage has been decreased with a passive or active RFC mechanism with a movable magnet track. The cost-effective passive RFC mechanism cannot deal with variation of the motion profile although the high-end active RFC mechanism can be used for any motion profiles. In this paper, we propose semi-active RFC mechanism for a linear motor motion stage. The semi-active RFC mechanism adjusts damping of fixed coil without any external energy. Effectiveness of the semi-active RFC mechanism is confirmed with simulations.

Evaluating the role of dry ports in the port-hinterland settings: Conceptual framework and the case of Vietnam

Nguyen Lam Canh,Thai Vinh V.,Nguyen Duc Minh,Tran Mai Dong 한국해운물류학회 2021 The Asian journal of shipping and Logistics Vol.37 No.4

Analyzing the dry ports’ impacts on different stakeholders is imperative for assessing the feasibility of a dry port project and promoting the collaboration among such parties to optimize the supply chain between inland customers and seaports. This paper aims at developing a conceptual framework to evaluate the role of dry ports from multi-criteria and multi-stakeholder approaches. Based on an extensive literature review, a hierarchy of evaluation criteria was developed from the perspectives of three main stakeholder groups, i.e. dry port users, seaport-based players and community. Interviews were then carried out to verify the face validity of the initially proposed framework given the context of Vietnam, followed by a survey assessing the dry port’s contributions. The findings highlight the major role of dry port users in driving the success of a dry port, while also recognizes significant roles of seaport-based players and the community. The study provides insights into how different stakeholder groups might value the contribution of dry ports and demonstrates that dry port characteristics have apparent impacts on their role as perceived by each group. Finally, this research points out the current issues of the Vietnamese dry port system and provides re commendations and managerial implications accordingly.

Phosphate removal from aqueous solutions using (vinylbenzyl)trimethylammonium chloride grafted onto polyester fibers

Park, HyunJu,Nguyen, Duc Canh,Na, Choo-Ki IWA Publishing 2015 Water Science & Technology Vol.71 No.12

<P>In this study, we investigated the removal of phosphate from aqueous solutions using (vinylbenzyl)-trimethylammonium chloride <B>(</B>VBTAC) grafted onto poly(ethylene terephthalate) (PET) fibers (PET<I>-g-</I>VBTAC). Batch-mode experiments were conducted using various contact times, initial phosphate concentrations, temperatures, pH values, and competing anions, to understand phosphate sorption onto PET<I>-g-</I>VBTAC. The phosphate sorption capacity of PET<I>-g-</I>VBTAC increased with increasing solution pH and was highest near pH 7. The equilibrium data fitted the Langmuir isotherm model well. The maximum sorption capacity (<I>q</I><SUB>m</SUB>) of PET<I>-g-</I>VBTAC for phosphate was 55.6–56.0 mg/g at 25–45 °C. The sorption process followed a pseudo-second-order kinetic model. The obtained values of the mean free energy indicated that sorption of phosphate on PET<I>-g-</I>VBTAC occurs via ion exchange. Thermodynamic parameters, enthalpy change, entropy change, and Gibb's free energy, confirmed that phosphate sorption was spontaneous and endothermic. The adverse effects of competing anions on phosphate removal by PET<I>-g-</I>VBTAC were insignificant. These results demonstrate that PET<I>-g-</I>VBTAC effectively removes phosphate from aqueous solutions by ion exchange.</P>

Deep learning-based functional assessment of piezoelectric-based smart interface under various degradations

Thanh-Truong Nguyen,Jeong-Tae Kim,Quoc-Bao Ta,Duc-Duy Ho,Thi Tuong Vy Phan,Thanh-Canh Huynh 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.1

The piezoelectric-based smart interface technique has shown promising prospects for electro-mechanical impedance (EMI)-based damage detection with various successful applications. During the process of EMI monitoring and damage identification, the operational functionality of the smart interface device is a major concern. In this study, common functional degradations that occurred in the smart interface are diagnosed using a deep learning-based method. Firstly, the effect of functional degradations on the EMI responses is analytically discussed. Secondly, a critical structural joint is selected as the test structure from which EM measurement using the smart interface is conducted. Thirdly, a numerical model corresponding to the experimental model is established and updated to reproduce the measured EMI responses. By using the updated numerical model, the EMI responses of the smart interface under the common functional degradations, such as the shear lag effect, the adhesive debonding, the sensor breakage, and the interface detaching, are simulated; then, the functional degradation-induced EMI changes are characterized. Finally, a convolutional neural network (CNN)-based functional assessment method is newly proposed for the smart interface. The CNN can automatically extract and directly learn optimal features from the raw EMI signals without preprocessing. The CNN is trained and tested using the datasets obtained from the updated numerical model. The obtained results show that the proposed method was successful to classify four types of common defects in the smart interface, even under the effect of noises.