• Journal of Sensor Science and Technology
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• v.26 no.5
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• pp.331-337
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• 2017

A readout circuit for a tactile sensor pad based on force sensing resistors was proposed, which was composed of an analog signal conditioning circuit and a digital circuit with a microcontroller. The conventional signal conditioning circuit has a dc offset voltage in the output signal, which results from the reference voltage applied to the FSR devices. The offset voltage reduces the dynamic range of the circuit and makes it difficult to operate the circuit under a low voltage power supply. In the proposed signal conditioning circuit, the dc offset voltage was removed completely. The microcontroller with A/D converter and D/A converter was used to enlarge the measurement range of pressure. For this, the microcontroller adjusts the FSR reference voltage according to the resistance magnitude of FSR under pressure. The operation of the proposed readout circuit which was connected to a tactile sensor pad with $5{\times}10$ FSR array was verified experimentally. The experimental results show the proposed readout circuit has the wider measurement range of pressure than the conventional circuit. The proposed circuit is suitable for low voltage and low power applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.622-628
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• 2016

As the suction pad-supporting bike carrier attached to a car may be subject to an excessive dynamic load due to random vibrations and centrifugal forces during driving, its structural safety is of great concern. To examine this, the finite-element method with a fluid-structure interaction should be used because the pressure on the pad bottom is changed in real time according to the fluctuations of the force or the moment applied on the pad. This method, however, has high computing costs in terms of modeling efforts and software expense. Moreover, the accuracy of computation is not easily guaranteed. Therefore, a new method combining the experiment and computation is proposed in this paper: the bottom pressure and contact area of the pad under varying loads was measured in real time and the acquired data are then used in the nonlinear elastic finite-element calculations. The computational and experimental results obtained with the product under development showed that the safety margin of the pad under the axial loading is relatively sufficient, whereas with an excessive rotational loading, the pad is vulnerable to separation or a local surface damage; hence, the safety margin may not be secured. The predicted contact behavior under the variation of the magnitude and type of the loading were in good agreement with the one from the experiment. The proposed analysis method in this study could be used in the design of similar vacuum pad systems.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.55-67
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• 2010

The electrical properties of a back drilled via-hole (BDH) without the open-stub and the plated through via-hole (PTH) with the open-stub, which is called the conventional structure, in a high-count multi~layered (HCML) printed circuit board (PCB) were investigated for a high-speed digital system, and a selected inner layer to transmit a high-speed signal was farthest away from the side to mount the component. Within 10 GHz of the broadband frequency, a design of experiment (DOE) methodology was carried out with three cause factors of each via-hole structure, which were the distance between the via-holes, the dimensions of drilling pad and the anti-pad in the ground plane, and then the relation between cause and result factors which were the maximum return loss, the half-power frequency, and the minimum insertion loss was analyzed. Subsequently, the empirical formulae resulting in a macro model were extracted and compared with the experiment results. Even, out of the cause range, the calculated results obtained from the macro model can be also matched with the measured results within 5 % of the error.

• Tribology and Lubricants
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• v.33 no.2
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• pp.71-78
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• 2017

The drag torque in the wet clutch system of a dual clutch transmission system is investigated because it is relatively high, up to 10 of the total output torque of the engine, even when the clutch is in the disengagement state with zero torque transfer. Drag torque results from the shear resistance of the DCTF between the friction pad and separator plate. To reduce the drag torque for ensuring fuel economy, the groove pattern of the wet clutch friction pad is designed to have a high flow rate through the pattern groove. In this study, four types of groove patterns on the friction pad are designed. The volume fraction of the DCTF (VOF) and hydrodynamic pressure developments in the gap between the friction pad and separator plate are computed to correlate with the computation of the drag torque. From the computational results, it is found that a high VOF and hydrodynamics increase the drag torque resulting from the shear resistance of the DCTF. Therefore, a patterned groove design should be used for increasing the flow rate to have more air parts in the gap to reduce the drag torque. In this study, ANSYS FLUENT is used to solve the flow analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.245-252
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• 2016

In this study, an alternative bend design is proposed to overcome the aging problem in piping bends. In this design, the foam pad is not included. Finite element analysis was performed based on the total pipe diameter. From this analysis, the shape of the Shear Control Ring (SCR) was determined. Temperature, stress, and other data of the proposed reinforced pipe were acquired and analyzed after the test was performed. The value of the thermal stress for the reinforced steel pipe satisfied the required standard without the foam pad based on the manufacturing of the reinforced fitting and construction site of the test. The reinforcement provided a shear strength level for the foam pad that resulted in maximum shear stress less than stress based on the original foam pad applied at the pipe bend. Additionally, an increasing factor of safety effect for the reinforced fitting application was discovered.

• Journal of Fashion Business
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• v.21 no.2
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• pp.105-112
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• 2017

A string wallcovering is a kind of textile wallcovering which is made of cellulose fiber yarn laminated on base paper. Compared with normal paper or PVC wallpaper, a string wallcovering is preferred continually in the interior design market, as it is not only environmentally friendly but it also has less cost on mass production without the weaving process and has a natural visual effect, excellent functionality such as thermo keeping, permeability, sound absorption. However, in the dyeing process, it is not appropriate to use plenty of energy such as water, electricity, steam or chemicals considering the environmental trend and the government policy plenty of energy such as water, electricity, steam or chemicals. Currently, a string wallcovering is made of raw white yarn and padding with direct dye or pigment which includes toxic elements, especially the use of direct dye is restricted in a part of the developed country due to inclusion of azo. In this study, we researched dyeing based on cold pad batch dyeing of a string wallcovering with reactive dyestuff. The peel strength and bending depth test confirmed that the optimum adhesive type and spread amount improved the water resistance of the string wallcovering. Also, pad batch dyeing with optimum reactive dyestuff enhanced the color fastness to light and rubbing in dry and wet conditions. Additionally, for improvement of color fastness to rubbing in a wet condition, the additional treatment finishing without soaping process which is used water. The results of this study can be used as basic data for environmentally friendly and energy saving of the textile wallcovering.

• Journal of Aerospace System Engineering
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• v.14 no.3
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• pp.51-59
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• 2020

In the case of cubesat, a PCB-based deployable solar panel advantageous in terms of weight reduction and electrical circuit design is widely used considering the limited weight and volume of satellites. However, because of the low thermal conductivity of PCB, there is a limit relative to heat dissipation. In this paper, the thermal gap pad is applied to the contact between the PCB-based solar panel and the aluminum stiffener mounted on the outside of the panel. Thus, the heat transfer from the solar cell to the rear side of the panel is facilitated. It maximizes the heat dissipation performance while maintaining the merits of PCB panel, and thus, it is possible to improve the power generation efficiency from reducing the temperature of the solar cell. The effectiveness of the thermal design of the 6U cubesat's deployable solar panel using the thermal gap pad has been verified through on-orbit thermal analysis based on the results, compared with the conventional PCB-based solar panel.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.1
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• pp.10-19
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• 1986

This is the last part of the four-part describing the development of a packet-switched computer communication network named the KORNET. In this paper we describe the design and implementation of the packet assembler/dissassembler (PAD) protocol for the asynchronous channel service, and of the network management softwares. The line processing module-B(LPMB) system supporting the asynchronous line includes a PAD protocol, a packet mode DTE/DCE protocol converting to the X.25 protocol, and the asynchronous receiver/transmitter(ART) software. The network management software is operated in master central processing module(MCPM) which includes virtual circuit management (VCM) managing the user channel, the routing management and the high level protocol for communication between the network management center (NMC) and the network node processor(NNP). In this paper, the design, implementation and operation of the softwares for the above service functions will be described in detail.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.821-827
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• 2023

In this study, the aircraft technical standards of the Korea and the United States were analyzed to derive the dynamometer test procedure required to prove the compatibility for flight test certification of the metal brake pad for transport aircraft. Since the design modification of the brake systems is classified as a major change, the STC(Supplemental Type Certificate) and the PMA(Parts Manufacturer Approval) are required. In accordance with the TSO-C135a, the technical standard order for brake system in the United States, the design landing-stop test, accelerate-stop test, and most severe landing stop test were selected among the test items for flight test. The conditions for the dynamometer test are determined according to the specifications provided by aircraft manufacturer, and the brake pad condition, deceleration, and the number of test are defined according to the TSO-C135a.

• Tribology and Lubricants
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• v.30 no.1
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• pp.9-14
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• 2014

In this Part II study, rotordynamic stability analyses were carried out to confirm improvements to the stability of a process high-speed lightweight centrifugal compressor, depending on the effects of tilting pad journal bearing designs. The bearing design variables considered were the clearances, LBPs, LOPs, and preloads. The results showed that the rotordynamic stability of the subject compressor rotor-bearing system improves exactly in accordance with the effects of the bearing design variables, which were determined in the preceding Part I study, owing to reduced bearing stiffnesses. Specifically, it was confirmed that the stability of the rotor system can be greatly improved by increasing both the machined and assembled bearing clearances, but there were no stability improvements by simply changing from an LBP to an LOP design. In addition, it was confirmed that for given fixed machined bearing clearances, the stability can be additionally improved by decreasing the preloads, i.e., by increasing the assembled clearances. In conclusion, it may be necessary to improve the designs of the original tilting pad bearings to obtain a sufficient margin of rotordynamic stability against a possible aerodynamic cross-coupled stiffness in a process high-speed centrifugal compressor. Thus, increasing the machined and assembled bearing clearances and decreasing the preload could be effective solutions.