• Title/Summary/Keyword: output force

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Fiscal Convergence and Total Factor Productivity: Firm-Level Evidence from Pakistan

  • KHAN, Usman Shaukat;KHAN, Muhammad Arshad;NAWAZ, Saima;RAHMAN, Abdul
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.10
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    • pp.555-569
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    • 2020
  • This study examines the impact of corporate tax, a fiscal measure along with trade liberalization and research and development on total factor productivity for a panel of 153 industrial firms listed on the Pakistan Stock Exchange over the period 1997-2017. For empirical analysis, we employ the system generalized method of moment estimator. In the first step, we estimate industrial production function and the results reveal that raw material, industrial labour force and energy play vital role in enhancing industrial production. Whereas, industrial capital exerts negative impact on industrial output. We also measured total factor productivity using the production elasticities. In the second step, we examine the impact of corporate tax, trade liberalization and research and development on total factor productivity. The results indicate that higher level of corporate tax exerts negative impact on total factor productivity. The findings reveal that higher corporate taxation discourages industrial firms to undertake research and development thereby exerting adverse impact on total factor productivity of firms. The impact of trade liberalization proxied by average tariff is positive while customs duty and sales tax negatively impact firm-level total factor productivity. These findings provide useful insights for managers, investors and policy makers in Pakistan.

Study on the frequency of self-excited pulse jet

  • Wang, Jian;Li, Jiangyun;Guan, Kai;Ma, Tianyou
    • International Journal of Fluid Machinery and Systems
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    • v.6 no.4
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    • pp.206-212
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    • 2013
  • Self-excited pulse jet is a specific nozzle with a closed chamber which can change a continuous jet into a pulse one. Energy of the pulse jet can be output not only unevenly but also with multifrequency. With the peak pressure of pulse jet, the hitting power would be 2~2.5 times higher than that of continuous jet. In order to reveal the correlation between the self-excited pulse frequency and nozzle diameter ratio, nozzle spacing and operating pressure, the model of 3D unsteady cavitation model has been used. We found that with the same nozzle structure parameters and the different operating pressure, the self-excited frequency and the width of peak crest are different, but the wave profiles are similar. With FFT, we also found that the less bandwidth of amplitude in low frequency range will lead to the wider wave crest of outlet velocity in its time domain, and the larger force of the strike will be gained. By studying the St of self-excite nozzle, not only the frequency of a certain nozzle can be predicted, but also a nozzle structure with a certain frequency can be designed.

Modal Testing of Mechanical Structures Subject to Operational Excitation Forces

  • Gade, Svend;Moller, Nis B.;Herlufsen, Henrik;Brincker, Rune;Andersen, Palle
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1162-1165
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    • 2001
  • Operational Modal Analysis also known as Output Only Modal Analysis has in the recent years been used for extracting modal parameters of civil engineering structures and is now becoming popular for mechanical structures. The advantage of the method is that no artificial excitation need to be applied to the structure or force signals to be measured. All the parameter estimation is based upon the response signals, thereby minimising the work of preparation for the test. This test case is a controlled lab set-up enabling different parameter estimation methods techniques to be used and compared to the Operational Modal Analysis. For Operational Modal Analysis two different estimation techniques are used: a non-parametric technique based on Frequency Domain Decomposition (FDD), and a parametric technique working on the raw data in time domain, a data driven Stochastic Subspace Identification (SS!) algorithm. These are compared to other methods such as traditional Modal Analysis.

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A Study on the Characteristic of Energy Harvesting Mechanism for Batteryless Wireless Switch (배터리없는 무선 스위치를 위한 에너지 하베스팅 메커니즘의 특성 연구)

  • Choi, Yeon-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.5
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    • pp.3114-3120
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    • 2014
  • Wireless emergency call switch used in industry, the most important thing is the sustainable power supply. This paper describes the development and performance test results of a compact electromagnetic energy harvesting mechanism for batteryless wireless switch. This paper summarizes proposed structure design and magnetic field analysis results of the mechanism to generate an induced electromotive force using 2mm stroke of a single push action. This analysis results show the power output of the proposed mechanism up to VDC $4.5V{\pm}25%$ and it can hold up to 65ms of the power generation with greater than 2.5V.

Fuzzy Sky-hook Control of Semi-active Suspension System Using Rotary MR Damper (회전형 MR 댐퍼를 이용한 반능동 현가장치의 퍼지 스카이-훅 제어)

  • Cho, Jeong-Mok;Joh, Joong-Seon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.5
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    • pp.701-706
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    • 2007
  • Recently, a number of researches about linear magnetorheological(MR) damper using valve-mode characteristics of MR fluid have sufficiently undertaken, but researches about rotary MR damper using shear-mode characteristics of MR fluid are not enough. In this paper, we performed vibration control of shear-mode MR damper for unlimited rotating actuator of mobile robot. Also fuzzy logic based vibration control for shear-mode MR damper is suggested. The parameters, like scaling factor of input/output and center of the triangular membership functions associated with the different linguistic variables, are tuned by genetic algorithm. Simulation results demonstrate the effectiveness of the fuzzy-skyhook controller for vibration control of shear-mode MR damper under impact force.

A Study of Hydraulic Actuator Based On Electro Servo Valve For A Walking Robot (보행 로봇을 위한 서보밸브 구동 유압 액추에이터의 특성 분석)

  • Cho, Jung San
    • Journal of Drive and Control
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    • v.13 no.2
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    • pp.26-33
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    • 2016
  • This paper describes of a mathematical and real experimental analysis for a walking robot which uses servo valve driven hydraulic actuator. Recently, many researchers are developing a walking robot based on hydraulic systems for the difficult and dangerous missions such as walking in the rough terrain and carrying a heavy load. In order to design and control a walking robot, the characteristics of the hydraulic actuators in the joint through the view point of walking such as controllability and backdrivability must be analyzed. A general mathematical model was used for analysis and proceeds to position and pressure changes characteristic of the input and backdrivability experiment. The result shows the actuator is a velocity source, had a high impedance, the output stiffness is high in contact with the rigid external force. So stand above the controller and instruments that complement the design characteristics can be seen the need to apply a hydraulic actuator in walking robot.

A Case Study on the Reduction of Noise and Vibration at the Backpass Heat Surface in the Power Plant Boiler (300MW급 증기터빈의 베어링 윤활유 온도조정에 의한 오일휩 제거방법에 관한 연구)

  • Hwang, Dal-Yeon;Moon, Seung-Jae;Lee, Jae-Heon
    • Plant Journal
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    • v.4 no.4
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    • pp.56-61
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    • 2008
  • The phenomena of oil whip in steam turbines take place for the unbalance force between a rotor shaft and bearing oil film. The several parameters that affect onset of oil whip have been well known. However, the major parameter of oil whip is shaft mis-alinement. A oil whip causes the high vibration and the shutdown of rotor system. We mostly stop the steam turbine to adjust a shaft re-alinement concerning oil whip. In this case, it needs many costs for maintenance and long shutdown times. In this study, we study and observe the oil whip of the 300MW steam turbine in many years and we conduct the field test for another steam turbine for reducing vibration from oil whip. The results of this study are that a oil whip takes place with a particular rotating speed or a particular turbine output and the oil temperature change is a very effective method for on-line oil whip treatment.

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Vibration characteristics of caisson breakwater for various waves, sea levels, and foundations

  • Lee, So-Young;Huynh, Thanh-Canh;Dang, Ngoc-Loi;Kim, Jeong-Tae
    • Smart Structures and Systems
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    • v.24 no.4
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    • pp.525-539
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    • 2019
  • In this study, vibration characteristics of a gravity-based caisson-foundation breakwater system are investigated for ambient and geometric parameters such as various waves, sea levels, and foundation conditions. To achieve the objective, following approaches are implemented. Firstly, operational modal analysis methods are selected to identify vibration modes from output-only dynamic responses. Secondly, a finite element model of an existing caisson-foundation breakwater system is established by using a structural analysis program, ANSYS. Thirdly, forced vibration analyses are performed on the caisson-foundation system for two types of external forces such as controlled impacts and wave-induced dynamic pressures. For the ideal impact, the wave force is converted to a triangular impulse function. For the wave flow, the wave pressure acting on the system is obtained from wave field analysis. Fourthly, vibration modes of the caisson-foundation system are identified from the forced vibration responses by combined use of the operational modal analysis methods. Finally, vibration characteristics of the caisson-foundation system are investigated under various waves, sea levels, and foundations. Relative effects of foundation conditions on vibration characteristics are distinguished from that induced by waves and sea levels.

Contact Resistance between Flexible Tactile Sensor Fabricated by Direct Write and Copper Alloy Terminals (Direct write 기술로 제작된 유연촉각센서와 동합금 단자의 접촉저항)

  • Kim, Jindong;Bae, Yonghwan;Yun, Haeyong;Lee, Inhwan;Kim, Hochan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.10
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    • pp.111-116
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    • 2020
  • Flexible tactile sensors, which are primarily used as grippers in robots, are mainly used to handle highly elastic or highly flexible objects. That is, flexible grippers are used when an object cannot be sufficiently controlled by applying a specific output force or taking a specific grabbing action. This is because a flexible tactile sensor needs to measure the pressure applied directly to held objects while deforming according to the shape of the object to be handled. CNT-based sensors used to be made from a highly flexible polymer to give flexibility and it is known that the sensors are greatly affected by the contact resistance of the terminal that connects the sensor to an electrical circuit; therefore, this paper clarifies the contact resistance of MWCNTs-based flexible tactile sensors and terminals. The effects of main and plating materials for terminals are investigated and the combinations of main and plating materials that exhibit contact resistance are measured in a typical industrial environment.

Optimized AI controller for reinforced concrete frame structures under earthquake excitation

  • Chen, Tim;Crosbie, Robert C.;Anandkumarb, Azita;Melville, Charles;Chan, Jcy
    • Advances in concrete construction
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    • v.11 no.1
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    • pp.1-9
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    • 2021
  • This article discusses the issue of optimizing controller design issues, in which the artificial intelligence (AI) evolutionary bat (EB) optimization algorithm is combined with the fuzzy controller in the practical application of the building. The controller of the system design includes different sub-parts such as system initial condition parameters, EB optimal algorithm, fuzzy controller, stability analysis and sensor actuator. The advantage of the design is that for continuous systems with polytypic uncertainties, the integrated H2/H∞ robust output strategy with modified criterion is derived by asymptotically adjusting design parameters. Numerical verification of the time domain and the frequency domain shows that the novel system design provides precise prediction and control of the structural displacement response, which is necessary for the active control structure in the fuzzy model. Due to genetic algorithm (GA), we use a hierarchical conditions of the Hurwitz matrix test technique and the limits of average performance, Hierarchical Fitness Function Structure (HFFS). The dynamic fuzzy controller proposed in this paper is used to find the optimal control force required for active nonlinear control of building structures. This method has achieved successful results in closed system design from the example.