• Title/Summary/Keyword: low velocity

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A review of herbal medicines for chemotherapy induced peripheral neuropathy (한약을 이용한 chemotherapy-induced peripheral neuropathy (CIPN) 치료 관련 무작위 배정 임상 시험에 대한 고찰)

  • Park, Bongki
    • Journal of Korean Traditional Oncology
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    • v.21 no.2
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    • pp.51-61
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    • 2016
  • Background : Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse effect in cancer patients who were exposed to chemotherapy. CIPN impacts on the quality of life and could delay chemotherapy. The aim of this review was to assess the therapeutic effectiveness of herbal medicine in CIPN patients. Methods : Randomized controlled trials (RCTs) were included in this review. We searched MEDLINE, Cochrane database, EMBASE, CNKI, Wanfang and four Korean databases without restrictions on time or language. The risk of bias was assessed using the Cochrane risk of bias tool. Results : Eleven RCTs involving 706 patients met the inclusion criteria. Eleven different herbal medicines were examined in the included trials. Almost RCTs showed insufficiency in the reporting randomization method and allocation concealment. One trial used allocation concealment and a double-blinding method. Five studies reported that participants dropped out of RCTs and conducted an 'as-treated analysis'. One trials reported adverse effects of herbal medicine. In ten of the eleven trials, the use of herbal medicine had shown significant differences in clinical symptoms or nerve conduction velocity. Conclusions : The use of herbal medicines for CIPN showed significant improvements in the management of CIPN. However, conclusions cannot be drawn because of the generally low quality of methodology and low quantity of data for each single herbal medicine. Further rigorous trials are needed.

Flame simulation on the two stage heavy oil combustion (이단중유연소 버너의 수치해석적 연구)

  • Lee, Sung-Soo;Kim, Hyuck-Ju;Park, Byoung-Sik;Kim, Jong-Jin;Choi, Gyu-Sung
    • 한국연소학회:학술대회논문집
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    • 2002.11a
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    • pp.209-214
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    • 2002
  • Computations were performed to investigate the flow, temperature and pollutants in two stage heavy-oil combustion burner. The burner geometry and flow conditions were provided by a burner company. The goal of the study is to understand combustion phenomena according to each air inlet's velocity, excessive air ratio and air temperature through CFD. Air flow rates at two inlets are adjusted by a damper inside a burner. Here, injection conditions of liquid fuel are kept constant throughout all simulations. This assumption is made in order to limit the complexity of oil combustion though it may cause some disagreement. The final goal of this research is to design a Low-NOx heavy oil combustion burner through comparison between computational study and experimental ones. Besides experiments, simulation works can give us insights into heavy oil combustion and help us design a Low NOx burner while saving time and cost. The computational study is based on k-e model, P-1 radiation model(WSGGM) and PDF, and is implemented on a commercial code, FLUENT.

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An Investigation on Flow and Structural Characteristics of Heat Exchanger in Rankine Steam Cycle for Co-generation System (기관 폐열 회수를 위한 열교환기의 Baffle 길이 변경에 따른 성능 예측에 관한 수치 해석적 연구)

  • Ryu, Kyuhyenn;Kim, Kusung;Lee, Younghum;Kang, Seokho;Park, Gibeom
    • New & Renewable Energy
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    • v.9 no.4
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    • pp.32-39
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    • 2013
  • A 2-loop waste heat recovery system with Rankine steam cycles for the improvement of fuel efficiency of gasoline vehicles has been investigated. A high temperature loop is used to recover waste heat from exhaust gas and a low temperature loop is used to recover waste heat from cold engine coolant. This paper has dealt with a layout of low temperature loop system, the review of the velocity contours through numerical analysis. According to the result of analysis, the designed heat exchanger. And comparing with flow analysis results, LT Boiler is safe to operation.

Evaluation of Residual Strength of Carbon/Epoxy Laminates Due to Low Velocity Impact Damage (Carbon/Epoxy 적층판의 저속충격손상에 따른 잔류강도 평가)

  • Kang, Min-Sung;Choi, Jung-Hun;Kim, Sang-Young;Koo, Jae-Mean;Seok, Chang-Sung
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.2
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    • pp.102-108
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    • 2010
  • Recently, carbon fiber reinforced plastic(CFRP) composite materials have been widely used in various fields of engineering because of its advanced properties. Also, CFRP composite materials offer new design flexibilities, corrosion and wear resistance, low thermal conductivity and increased fatigue life. However CFRP composite materials are susceptible to impact damage due to their lack of through-thickness reinforcement and it causes large drops in the load-carrying capacity of a structure. Therefore, the impact damage behavior and subsequently load-carrying capacity of impacted composite materials deserve careful investigation. In this study, the residual strength and impact characteristics of plain-woven CFRP composites with impact damage are investigated under axial tensile test. By using obtained residual strength and Tan-Cheng failure criterion, residual strength of CFRP laminate with arbitrary fiber angle were evaluated.

Intelligent control of pneumatic actuator using MPWM (MPWM을 이용한 공압 실린더의 지능제어)

  • 송인성;표성만;안경관;양순용;이병룡
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.530-535
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    • 2002
  • Pneumatic control system has been applied to build many industrial automation systems. But most of them are sequence control type because of their low costs, safety, reliability, etc. Pneumatic servo system is rarely applied to real industrial fields because accurate position control is very difficult due to its nonlinearity and compressibility of air. In pneumatic servo control system, a pneumatic servo valve can be applied, But it is very expensive and has no advantage of low cost compared with a common pneumatic system. This paper is concerned with the accurate position control of a rodless pneumatic cylinder using on/off solenoid valve. A novel Intelligent Modified Pulse Width Modulation(MPWM) is newly proposed. The control performance of this pneumatic cylinder depends on the external loads. To overcome this problem, switching of control parameter using artificial neural network is newly proposed, which estimates external loads on rodless pneumatic cylinder using this training neural network. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied in the switching control the system. The effectiveness of the proposed control algorithms are demonstrated through experiments nth various loads.

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Crash Discrimination Algorithm with Two Crash Severity Levels Based on Seat-belt Status (안전띠 착용 유무에 근거한 두 단계의 충돌 가혹도 수준을 갖는 충돌 판별 알고리즘)

  • 박서욱;이재협
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.2
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    • pp.148-156
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    • 2003
  • Many car manufacturers have frequently adopted an aggressive inflator and a lower threshold speed for airbag deployment in order to meet an injury requirement for unbolted occupant at high speed crash test. Consequently, today's occupant safety restraint system has a weakness due to an airbag induced injury at low speed crash event. This paper proposes a new crash algorithm to improve the weakness by suppressing airbag deployment at low speed crash event in case of belted condition. The proposed algorithm consists of two major blocks-crash severity algorithm and deployment logic block. The first block decides crash severity with two levels by means of velocity and crash energy calculation from acceleration signal. The second block implemented by simple AND/OR logic combines the crash severity level and seat belt status information to generate firing commands for airbag and belt pretensioner. Furthermore, it can be extended to adopt additional sensor information from passenger presence detection sensor and safing sensor. A simulation using real crash data for a 1,800cc passenger vehicle has been conducted to verify the performance of proposed algorithm.

COMBUSTION AND EMISSION CHARACTERISTICS OF A TURBOCHARGED DIESEL ENGINE FUELLED WITH DIMETHYL ETHER

  • Wu, J.;Huang, Z.;Qiao, X.;Lu, J.;Zhang, L.;Zhang, J.
    • International Journal of Automotive Technology
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    • v.7 no.6
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    • pp.645-652
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    • 2006
  • This paper is concerned with an experimental study of a turbocharged diesel engine operating on dimethyl ether(DME). The combustion and emission characteristics of DME engine were investigated. The results showed that the maximum torque and power with DME could achieve a greater level compared to diesel operation, particularly at low speeds; the brake specific fuel consumption with DME was lower than the diesel at low and middle engine speeds. The injection delay of DME was longer than that of diesel. However, the maximum cylinder pressure, maximum pressure rise rate and combustion noises of DME engine were lower than those of diesel. The combustion velocity of DME was faster than that of diesel, resulting in a shorter combustion duration of DME. Compared with the diesel engine, $NO_x$ emissions of the DME engine were reduced by 41.6% on ESC data. The DME engine was smoke free at all operating points of the engine.

Parametric Studies and Performance Analysis of a Biplane Micro Air Vehicle

  • Maqsood, Adnan;Go, Tiauw Hiong
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.3
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    • pp.229-236
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    • 2013
  • This paper presents the experimental investigation of a biplane micro air vehicle. The effects of geometric parameters, gap, stagger, and decalage angle are investigated at low Reynolds number (~150,000) in a low-speed wind tunnel. A rigid flat plate with an aspect ratio of one and square planform shape is used to evaluate all three geometric parameters. The side dimension of the single flat plate is 0.15 m. The goal is to find an optimal biplane configuration that should exceed monoplane performance by generating high lift and flying as slow as possible, in order to capture high-quality visual recordings. This configuration will directly help to fly at a lower velocity and to make tighter turns that are advantageous in restricted environments. The results show that the aerodynamic performance of the biplane MAV is significantly enhanced through the combination of gap and stagger effects. A performance comparison demonstrates the superiority of the optimal biplane configuration compared to a monoplane in cruise and glide phases. Moreover, no significant compromise is found for the range, endurance, and climb performance.

Prevention of Back Side Humping in Laser Welding of Al 5J32 Alloy by Using Laser Power Modulation (Al 5J32 합금의 레이저 용접에서 레이저출력 모듈레이션을 이용한 이면 험핑 비드의 안정화)

  • Ahn, Do-Chang;Kim, Cheol-Hee;Kim, Jae-Do
    • Journal of Welding and Joining
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    • v.29 no.4
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    • pp.80-84
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    • 2011
  • In the 5xxx series Al-Mg alloy, magnesium addition can increase the strength of aluminum alloy by solid solution strengthening but it has a relatively low melting and boiling temperature. During full -penetration laser welding of the Al-Mg alloys, its low boiling point and high vapor pressure brings about the spiky humping bead on the bottom side. Under back-side shielding, the spiking of back bead can be reduced but it restraints the process flexibility. In this study, a square pulse waveform modulation was employed to stabilize keyhole and back bead surface without back-side shielding. By using an experimental design, the bead shapes were evaluated for various process parameters such as the focal position, welding velocity and waveform parameters and the smooth back bead shape could be achieved.

Gravity Compensator for the Roll-pitch Rotation (Roll-pitch 중력 보상 기구 설계)

  • Cho, Chang-Hyun;Lee, Woo-Sub;Kang, Sung-Chul
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.7
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    • pp.688-694
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    • 2010
  • This paper presents a gravity compensator for the manipulator of a service robot. The manipulator of a service robot is operated with low velocity for the safety reason in most cases. In this situation gravitational torques generated by the mass of links are often much greater than dynamic torques for motion. A gravity compensator can counterbalance the gravitational torques, thereby enabling to utilize relatively low power motors. In this paper the gravity compensation for the roll-pitch rotation is considered which is often used for the shoulder joints of the manipulator of a service robot or humanoid robot. A gimbals is implemented and two 1-dof gravity compensators are equipped at the base. One compensates the gravitational torque at the roll joint and another provides the compensational torque for the gimbals. Various analyses showed that the proposed compensator can counterbalance the gravitational torques of 87% at the pitch joint and 50% at the roll joint. It is verified from dynamic simulations that the proposed compensator effectively counterbalances the gravitational torques.