• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.539-543
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• 2009

When the suction pressure of compressor decreases under its limit, the compression ratio is increased causing the malfunctions of compressor. As the method to decrease the compression ratio, hot gas bypass system is usually adopted in heat pump system. In the hot gas bypass system, the discharged gas from the compressor is bypassed into the compressor suction, which causes the increase of suction pressure and the decrease of compression ratio. In this study, the characteristics and performances of the hot gas bypass system in heat pump was investigated experimentally with a variation of the bypass flow rate ratio. With the increase of the bypass rate ratio, the compressor suction pressure was increased, even though the total capacity and COP was decreased. From the analysis of the experimental results, the optimum pressure control algorithm was suggested in this study.

• Journal of Chest Surgery
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• v.49 no.4
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• pp.225-231
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• 2016

Throughout its 30-year history, the right gastroepiploic artery (GEA) has been useful for in situ grafts in coronary artery bypass grafting (CABG). The early graft patency rate is high, and the late patency rate has improved by using the skeletonized GEA graft and proper target selection, which involves having a target coronary artery with a tight >90% stenosis. Total arterial revascularization with the internal thoracic artery and GEA grafts is an option for achieving better outcomes from CABG procedures.

• Journal of Chest Surgery
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• v.26 no.12
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• pp.920-925
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• 1993

Extra-anatomic bypass was proposed by Freeman in 1952 and has been used for patient with lower extremity arterial occlusion who had very high operative risk, especially elderly or severly illed patient.We had performed 14 cases of extra-anatomic bypasses from Jan. 1991 till July 1993 and having been following up them. Their results were summarized as follow. Among total 14 patients, 13 was male. Their mean age was 64.8 years old, ranged from 48 to 80. The most common complaint was pain on lower limb and they visited hospital 6.1 months in average after onset of symptom. Frequently, they were associated with systemic diseases such as generalized atherosclersis, hypertension, diabetes mellius, etc. Axillary artery was used as donor artery in 8 cases and crossover femoro-femoral or femoro-popliteal bypass was performed in 6 cases. Postoperative complications were notedd in 8 cases so their morbidity rate was 42.8%. Except for two contraindicated cases, one or more anticoagulants were used routinely . Among them, combined use of aspirin and persantine was most commonly applied.After bypass graft, nine cases were occluded beteween 10 and 53 months. So their average duration of freedom from reocclusion was 35.7 months and 3-year patency rate was 63%.

• Archives of Plastic Surgery
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• v.46 no.1
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• pp.46-56
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• 2019

Background When performing lymphovenous anastomosis, it is sometimes difficult to find venules in the proximity of an ideal lymphatic vessel that have a similar diameter to that of the lymphatic vessel. In this situation, larger venules can be used. Methods The authors evaluated the efficacy of and patient satisfaction with lymphovenous bypass with sleeve-in anastomosis. Between January 2014 and December 2016, we performed this procedure in 18 patients (eight upper extremities and 10 lower extremities) with secondary lymphedema. Lymphovenous bypass with sleeve-in anastomosis was performed under microscopy after injecting indocyanine green dye. The circumferential diameter was measured before lymphovenous bypass and at 1, 2, and 6 months after the procedure. An outcomes survey that included patients' qualitative satisfaction with lymphovenous bypass was conducted at 6 months postoperatively. Results Almost all patients showed quantitative improvements after surgery. The circumferential reduction rate in patients with stage II lymphedema of both the upper and lower extremities was significantly greater than in their counterparts with stage III/IV lymphedema. The circumferential reduction rate was lower in lower-extremity patients than in upper-extremity patients. Conclusions Lymphovenous bypass surgery with sleeve-in anastomosis in lymphedema patients is beneficial, and appears to be effective, when adequately-sized venules cannot be found in the proximity of an ideal lymphatic vessel.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.1
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• pp.11-19
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• 2001

To establish optimum cycle of the inverter-driven heat pump with a variation of frequency, the bypass orifice, which was a short tube haying a bypass hole in the middle, was designed and tested. Flow characteristics of the bypass orifice were measured as a function of orifice geometry and operating conditions. Flow trends with respect to frequency were compared with those of short tube orifices and capillary tubes. Generally, the bypass orifice showed the best flow trends among them. and it would enhance the seasonal energy efficiency ratio of an inverter heat pump system, Based on experimental data, a semi-empirical flow model was developed to predict mass flow rate through bypass orifices. The maximum difference between measured data and model`s prediction was within $\pm$5%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.109-116
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• 1999

To establish optimum cycle of the inverter-driven heat pump with a variation of frequency, the bypass orifice, which is a short tube having a bypass hole in the middle, was designed and tested. Flow characteristics of the bypass orifice were measured as a function of orifice geometry and operating conditions. Flow trends with respect to frequency were compared with those of short tube orifices and capillary tubes. Generally, the bypass orifice showed the best flow trends among them, that will enhance the seasonal energy efficiency ratio of an inverter heat pump system. Based on experimental data, the semi-empirical flow model was developed to predict mass flow rate through bypass orifices. The maximum difference between measured data and model's prediction was within ${\pm}5%$.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.437-440
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• 2005

In the present work, characteristics of the flow in CAGE of a steam turbine LP/HP Bypass control valve for thermal power plant are investigated. The flow field is analyzed numerically by solving steady three-dimensional Reynolds-averaged Navier-Stokes equations. Shear stress transport (SST) model is used as turbulence closure.

• Journal of Chest Surgery
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• v.23 no.2
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• pp.333-341
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• 1990

aortoiliac pattern, Group II; femoropopliteal pattern and Group g; tibioperoneal pattern. A majority of patients belonged to group I [27 cases], 8 patients came under group II .and none in group g. Thirty patients underwent bypass operation with autogenous saphenous vein or synthetic graft with or without concomitant lumbar sympathectomy. Remaining 5 patients were operated on with sympathectomy only, Bypass procedures were anatomic bypass in 22 cases: aortoiliac artery bypass in 11 cases, femoropopliteal artery bypass in 10 cases, sequential femoropopliteal artery bypass in one case and extra-anatomic bypass in 8 cases, axillary-bifemoral artery bypass in one case and femorofemoral artery bypass in 7 cases. Postoperative complications which mainly composed of superficial wound infection[5 cases] which were treated without any significant sequel in all cases and thrombosis[2 cases]. Three patients died whose causes of death were acute renal failure in 2 cases and myocardial infarction in other, The overall patency, rate was 70Zo in 5 years. In conclusion, the clinical pattern and operative outcome were similar to he western pattern and all cases of death did not related to operative procedures and ischemic symptoms were relieved by bypass operations except several cases. I think and recommend that all patients suffering chronic arterial insufficiency by atherosclerosis obliterans ought to be managed with urgent and adequate operative procedure.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.57-66
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• 1997

Successful energy conservation and good indcfor air quality (IAQ) are highly dependent on ventilation system. Air filtration is a primary solution of indoor air control strategies in terms of reducing energy consumption and improving ihdoor air quality. A conventional system with bypass filter, as it is called variable-air-volume/bypass filtration system (VAV/BPFS), is a variation of the conventional variable air volume (VAV) systems, which is designed to eliminate indoor air pollutant and to save energy. Bypass filtration system equipped with a high-efficiency particulate filter and carbon absorbent provides additional cleaned air into indoor environments and maintain good IAQ for human health. The objectives of this research were to compare the relative total decay rate of indoor air pollutant concentrations, and to develop a mathematical model simulating the performance of VAV/BPFS. All experiments were performed in chamber under the controlled conditions. The specific conclusions of this research are: 1. The VAV/BPFS system is more efficient than the VAV system in removing indoor air pollutant concentration. The total decay rates of aerosol, and total volatile organic compound (TVOC) for the VAV/BPFS system were higher than those of the conventional VAV system. 2. IAQ model predictions of each pollutant agree closely with the measured values. 3. According to IAQ model evaluation, reduction of outdoor supply air results in decreased dilution removal rate and on increased bypass filtration removal rate with the VAV/BPFS. As a results, we recommends the VAV/BPFS as an alternative to conventional VAV systems.

• Journal of Chest Surgery
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• v.27 no.10
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• pp.846-849
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• 1994

Extra-anatomic bypass is indicated for the limb salvage of patients with threatened limb loss especially those who have high risk of infection and death after general anesthesia. We did extra-anatomic bypass procedure nineteen times over a seven year, two month period on sixteen patients. Their mean follow up period was 41.3 months. Male to female ratio was 7:1. Major complaints were resting pain[36.8%], claudication[31.6%], cyanosis[15.8%] and ulcerative change[15.8%]. Associated diseases were hypertension, tuberculosis, chronic renal failure, atrial fibrillation, complete heart block and laryngeal cancer. Postoperative patency rates were 76.9% at 1 year, 72.7% at 2 years and 70% at 3 years. Limb salvage rate was 78.9%. Postoperative mortality rate was 10.5%.