The purpose of the study was to investigate the immediate effects of negative pressure soft tissue therapy on muscle tone, muscle stiffness and balance in patients with stroke. In total, 20 patients with stroke and assigned to the negative pressure soft tissue therapy group (NPST, n=10) or, placebo-negative pressure soft tissue therapy group(Placebo-NPST, n=10). Both groups underwent NPST or placebo-NPST once a day during the experimental period. MyotonPRO was used to assess the parameters for muscle tone and stiffness. Biorescue was used to assess the parameters for balance. Each group showed improvements in muscle tone, muscle stiffness, and balance ability (p<.05). Especially, Muscle tone, muscle stiffness, and anterior length in the limit of stability were the significant improvement on NPST group (p<.05). The results of the study suggest that the NPST is effective in improving muscle tone, muscle stiffness, and balance ability in patients with stroke.

Muscle tone

Muscle stiffness

Stroke

10.20540/jiaptr.2018.9.2.1468

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Citations (3)

Influence of blade pass frequency vibrations on MCSA-based rotor fault detection of induction motors

2022 IEEE Energy Conversion Congress and Exposition (ECCE) (2016)

Yonghyun Park Myung Jeong Sang Bin Lee Jose A. Antonino‐Daviu Mike Teska

Motor current signature analysis (MCSA) has recently become widespread in industry for on-line detection of rotor cage faults in induction motors for preventing forced outages. Although it can provide low cost, remote monitoring of rotor faults, cases of false indications have been reported, where the causes of some false indications are still unknown. It is shown for the first time in this work that high-amplitude blade pass frequency (BPF) vibrations produced in pumps, fans, or compressors can cause false rotor fault indications, if the number of motor poles is an integer multiple of the number of blades. The influence of BPF vibration on MCSA based rotor fault detection is analyzed, and it is shown that the interaction between BPF vibration and rotor faults can produce false positive and negative fault indications. Alternative test methods capable of separating the influence of the BPF vibration and rotor faults are suggested for avoiding false MCSA alarms. The claims made in the paper are verified experimentally on a custom-built 380 V induction motor-centrifugal pump system setup.

Wound rotor motor

Condition Monitoring

10.1109/ecce.2016.7855199

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Citations (11)

Bezoar formation and obstruction caused by a surgical nylon thread after gastric bypass surgery

Endoscopy (2013)

Hyo Jin Kang Jong Jin Hyun Seung Han Kim Sung Yoon Jung Ja Seol Koo

A 58-year-old man presented with postprandial pain that radiated to the right shoulder and right flank. He had undergone a laparoscopy-assisted distal gastrectomy with Billroth II anastomosis 2 months previously for Borrmann type III advanced gastric cancer. The operation had been uneventful and he had been discharged without any complications. However, about a week after being discharged he developed abdominal discomfort that worsened after eating. Because of the progressive postprandial abdominal pain, which was unrelated to gastric dumping syndrome or blind loop syndrome, his oral intake had reduced and he had lost 6 kg since the time of the operation.

Dumping syndrome

Gastric Outlet Obstruction

10.1055/s-0033-1344991

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Citations (2)

Electrical Monitoring of Mechanical Looseness for Induction Motors With Sleeve Bearings

IEEE Transactions on Energy Conversion (2016)

Junyeong Jung Sang Bin Lee Chaewoong Lim Chang-Hee Cho Kwon-Hee Kim

Mechanical looseness in induction motors is a common problem caused by loose bolts, structural damage, improper fit, or increased clearance between components, and results in increased vibration and wear. Detection of mechanical looseness in the sleeve bearing of industrial motors mainly relies on vibration analysis. However, there are many motor applications in the field where vibration analysis cannot be applied due to cost, environmental, and/or sensitivity limitations. The feasibility of using existing voltage/current measurements available in the motor control center for remote, low-cost monitoring of mechanical looseness due to improper fit between the bearing-housing and bearing-shaft is evaluated in this paper. It is shown through experimental testing on a custom built sleeve bearing test setup and on a 6.6 kV, 2250 hp motor that monitoring of the one-half and one-third subsynchronous components in the instantaneous power spectrum can serve as a reliable indicator of mechanical looseness.

Condition Monitoring

Main bearing

10.1109/tec.2016.2583473

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Citations (22)

Trailing Edge PM Demagnetization in Surface PM Synchronous Motors: Analysis and Detection

2022 IEEE Energy Conversion Congress and Exposition (ECCE) (2022)

Jigyun Jeong Hyeonjun Lee Marcos Orviz Zapico Sang Bin Lee David Reigosa

Irreversible demagnetization of permanent magnets (PM) in PM synchronous motors (PMSM) degrades the performance and efficiency of the machine and drive system. Demagnetizing MMF applied to PMs operating at high temperature is known as one of the leading root causes of irreversible PM demagnetization. This is most likely to cause of demagnetization on the trailing edge of the PMs in all poles, as will be shown through simulation in this work. However, most of the work on detecting demagnetization faults focus on uniform or partial (local) PM demagnetization. In this paper, a comparative evaluation of back-EMF, stator current/voltage, and airgap flux analysis on the detectability of trailing edge PM demagnetization is given. It is shown that it is difficult to detect this type of fault with back-EMF or stator current/voltage based analysis, since trailing edge demagetization does not produce asymmetry between PMs. An experimental study on a 380 V, 8 pole, 1.8 kW surface PMSM with trailing edge PM demagnetization shows that airgap flux-based detection is the most reliable means of detecting this fault.

Trailing edge

10.1109/ecce50734.2022.9948151

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Citations (3)

Detection and Classification of Stator Turn Faults and High Resistance Electrical Connections for Induction Machines

Conference record (2007)

Jangho Yun Kwangwoon Lee Kwanghwan Lee Sang Bin Lee Jiyoon Yoo

The goal of stator winding turn fault detection is to detect the fault at an early stage, and shut down the machine immediately to prevent catastrophic motor failure due to the large fault current. A number of turn fault detection techniques have been proposed; however, there is currently no method available for distinguishing turn faults from high-resistance(R) connections, which also result in 3 phase system asymmetry. It is important to distinguish the two faults since a high-R connection does not necessarily require immediate motor shutdown. In this paper, new sensorless on-line monitoring techniques for detecting and classifying stator turn faults and high-R electrical connections in induction machines based on the zero sequence voltage or negative sequence current measurements are proposed. An experimental study on a 10 hp induction motor performed under simulated turn faults and high-resistance circuit conditions verifies that the two faults can be reliably detected and classified. The proposed technique helps improve the reliability, efficiency, and safety of the motor system and industrial plant, and also allows maintenance to be performed in a more efficient manner since the course of action can be determined based on the type and severity of the fault.

Fault indicator

10.1109/ias.2007.293

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Citations (2)

Measurement of beauty hadron pair production in 600 GeV/c π− emulsion interactions

Physics Letters B (1993)

K. Kodama N. Ushida A. Mokhtarani V. Paolone J. Volk

Fermilab

Nuclear emulsion

Pair production

10.1016/0370-2693(93)91446-t

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Citations (23)

Detection of broken outer cage bars for double cage induction motors under the startup transient

Jose A. Antonino‐Daviu M. Riera‐Guasp Joan Pons-Llinares Jongbin Park Sang Bin Lee

Unlike single cage rotor fault detection, FFT-based steady state spectrum analysis techniques can fail to detect outer cage faults in double cage induction motors due to the small outer cage current under running conditions. Double cage motors are typically employed in applications that require loaded starts. This makes the outer cage vulnerable to fatigue failure since it must withstand the high starting current and long startup time frequently. However, there are only a few publications that investigate detection techniques specifically for double cage motors. In this paper, considering that the influence of the faulty outer cage is strong at startup due to the large outer cage current, detection of outer cage faults under the startup transient is investigated. A Discrete Wavelet Transform-based method is proposed as a viable solution to detection of outer cage faults for double cage motors. An experimental study on fabricated copper double cage induction motors shows that the proposed method provides sensitive and reliable detection of double cage rotor faults compared to FFT.

Cage

Transient (computer programming)

Squirrel-cage rotor

10.1109/demped.2011.6063594

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Citations (12)