• Title/Summary/Keyword: Non-isolated technique

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A Study on the Mixing Characteristics in Complex Turbulent Flow by a Laser Induced Fluorescence Method (레이저 형광여기법(LIF)를 이용한 복잡 난류유동장의 혼합특성에 관한 연구)

  • Kim, Kyung-Chun;Jeong, Eun-Ho
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.542-547
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    • 2001
  • A non-intrusive Planar Laser-Induced Fluorescence(PLIF) technique was applied to study the turbulent mixing process in a Rushton turbine reactor. Instantaneous and ensemble averaged concentration fields are obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by a thin Nd:Yag laser sheet illuminating the whole center plane of the stirred tank. The gray level images captured by a 14-bit cooled CCD camera can be transformed to the local concentration values using a calibration matrix. The dye injection point was selected at the tank wall with three quarter height (3/4H) from the tank bottom to observe the mixing characteristics in upper bulk flow region. There exist distinct two time scales: the rapid decay of mean concentration in each region after the dye infusion reflects the large scale mixing while the followed slow decay reveals the small scale mixing. The temporal change of concentration probability functions conjectures the two sequential processes in the batch type mixing. An inactive column of water existed above the impeller disk, in which the fluid rotates with the shaft but is isolated from the mean bulk flow.

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A Study on the Mixing Characteristics in a Rushton Turbine Reactor by a Laser Induced Fluorescence Method (레이저 형광여기법(LIF)를 이용한 러쉬톤 터빈 교반기의 혼합특성에 관한 연구)

  • Jeong, Eun-Ho;Kim, Gyeong-Cheon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.8
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    • pp.1145-1152
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    • 2002
  • A non-intrusive Planar Laser-Induced Fluorescence(PLIF) technique was applied to study the turbulent mixing process in a Rushton turbine reactor. Instantaneous and ensemble averaged concentration fields was obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by a thin Nd:Yag laser sheet illuminating the whole center plane of the stirred tank. The gray level images captured by a 14-bit cooled CCD camera could be transformed to the local concentration values using a calibration matrix. The dye injection point was selected at the tank wall with three quarter. height (3/4H) from the tank bottom to observe the mixing characteristics in upper bulk flow region. There exist distinct two time scales: the rapid decay of mean concentration after the dye infusion reflects the large scale turbulent mixing while the fellowed slow decay reveals the small scale molecular mixing. The temporal change of concentration variance field conjectures the two sequential processes for the batch type mixing. An inactive column of water is existed above the impeller disk, in which the fluid rotates with the shaft but is isolated from the mean bulk flow.

A Non-isolated High Step-up DC/DC Converter with Low EMI and Voltage Stress for Renewable Energy Applications

  • Baharlou, Solmaz;Yazdani, Mohammad Rouhollah
    • Journal of Electrical Engineering and Technology
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    • v.12 no.3
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    • pp.1187-1194
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    • 2017
  • In this paper, a high step-up DC-DC PWM converter with continuous input current and low voltage stress is presented for renewable energy application. The proposed converter is composed of a boost converter integrated with an auxiliary step-up circuit. The auxiliary circuit uses an additional coupled inductor and a balancing capacitor with voltage doubler and switching capacitor technique to achieve high step-up voltage gain with an appropriate switch duty cycle. The switched capacitors are charged in parallel and discharged in series by the coupled inductor, stacking on the output capacitor. In the proposed converter, the voltage stress on the main switch is clamped, so a low voltage switch with low ON resistance can be used to reduce the conduction loss which results in the efficiency improvement. A detailed discussion on the operating principle and steady-state analyses are presented in the paper. To justify the theoretical analysis, experimental results of a 200W 40/400V prototype is presented. In addition, the conducted electromagnetic emissions are measured which shows a good EMC performance.

Effects of Zinc on Spontaneous Miniature GABA Release in Rat Hippocampal CA3 Pyramidal Neurons

  • Choi, Byung-Ju;Jang, Il-Sung
    • The Korean Journal of Physiology and Pharmacology
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    • v.10 no.2
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    • pp.59-64
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    • 2006
  • The effects of $Zn^{2+}$ on spontaneous glutamate and GABA release were tested in mechanically dissociated rat CA3 pyramidal neurons which retained functional presynaptic nerve terminals. The spontaneous miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs, respectively) were pharmacologically isolated and recorded using whole-cell patch clamp technique under voltage-clamp conditions. $Zn^{2+}$ at a lower concentration $(30{\mu}M)$ increased GABAergic mIPSC frequency without affecting mIPSC amplitude, but it decreased both mIPSC frequency and amplitude at higher concentrations $({\ge}300{\mu}M)$. In contrast, $Zn^{2+}$ (3 to $100{\mu}M$) did not affect glutamatergic mEPSCs, although it slightly decreased both mIPSC frequency and amplitude at $300{\mu}M$ concentration. Facilitatory effect of $Zn^{2+}$ on GABAergic mIPSC frequency was occluded either in $Ca^{2+}$-free external solution or in the presence of $100{\mu}M$ 4-aminopyridine, a non-selective $K^{+}$ channel blocker. The results suggest that $Zn^{2+}$ at lower concentrations depolarizes GABAergic nerve terminals by blocking $K^{+}$ channels and increases the probability of spontaneous GABA release. This $Zn^{2+}$-mediated modulation of spontaneous GABAergic transmission is likely to play an important role in the regulation of neuronal excitability within the hippocampal CA3 area.

Detection of IgG and IsM Antibodies with Immunofluoreseent Antibody Technique in Buman Trichomoniasis (질트리코모나스증에서 간접형광항체법을 이용한 혈청내 항질트리코모나스 IgG 및 IgM 항체의 측정)

  • 윤경찬;김경민;안명희;민득영;차동수
    • Parasites, Hosts and Diseases
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    • v.25 no.1
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    • pp.7-12
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    • 1987
  • The indirect fluorescent antibody(IFA) test was used to detect serum IgG and IgM antibodies to Trichomonas vaginalis in 31 vaginal trichomoniasis, 7 candidiasis and in 20 non-infected healthy women with antigen prepared from axonic culture of Trichomenas vaginalis isolated from vulvovaginitis patient. The results were as follows: 1. In 31 vaginal trichomoniasis the positive reactions of IgG antibody were 27 in the 1/8 dilution or higher and :l in the 1/4 dilution whereas in healthy women the reaction showed significantly low as in the 1/4 dilution or below. 2. The sensitivity and specificity of IFA test for IgG antibody to trichomonad antigen in this study were 87.1% and 100%, respectively. 3. No significant difference of IgM antibody levels between vaginal trichomoniasis and healthy women was observed. 4. No relation between the levels of IgG and IsM antibodies to trichomonad antigen by IFA test was observed. 5. No relation between the time lapse and the level of serum IgG antibodies in IFA test of vaginal trichomoniasis was regarded. In conclusion the present study suggests that IFA test in trichomoniasis could be a useful tool for detection of anti-trichomonad IgG antibodies and applicable as an immunodiagnostic method.

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Effectiveness of seismic isolation in a reinforced concrete structure with soft story

  • Hakan Ozturk;Esengul Cavdar;Gokhan Ozdemir
    • Structural Engineering and Mechanics
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    • v.87 no.5
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    • pp.405-418
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    • 2023
  • This study focused on the effectiveness of seismic isolation technique in case of a reinforced concrete structure with soft story defined as the stiffness irregularity between adjacent stories. In this context, a seismically isolated 3-story reinforced concrete structure was analyzed by gradually increasing the first story height (3.0, 4.5, and 6.0 m). The seismic isolation system of the structure is assumed to be composed of lead rubber bearings (LRB). In the analyses, isolators were modeled by both deteriorating (temperature-dependent analyses) and non-deteriorating (bounding analyses) hysteretic representations. The deterioration in strength of isolator is due to temperature rise in the lead core during cyclic motion. The ground motion pairs used in bi-directional nonlinear dynamic analyses were selected and scaled according to codified procedures. In the analyses, different isolation periods (Tiso) and characteristic strength to weight ratios (Q/W) were considered in order to determine the sensitivity of structural response to the isolator properties. Response quantities under consideration are floor accelerations, and interstory drift ratios. Analyses results are compared for both hysteretic representations of LRBs. Results are also used to assess the significance of the ratio between the horizontal stiffnesses of soft story and isolation system. It is revealed that seismic isolation is a viable method to reduce structural damage in structures with soft story.

Endoscopic ultrasound-guided intervention for inaccessible papilla in advanced malignant hilar biliary obstruction

  • Partha Pal;Sundeep Lakhtakia
    • Clinical Endoscopy
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    • v.56 no.2
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    • pp.143-154
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    • 2023
  • Advanced malignant hilar biliary obstruction (MHBO) with inaccessible papilla poses a significant challenge to endoscopists, as drainage of multiple liver segments may be warranted. Transpapillary drainage may not be feasible in patients with surgically altered anatomy, duodenal stenosis, prior duodenal self-expanding metal stent, and after initial transpapillary drainage, but require re-intervention for draining separated liver segments. Endoscopic ultrasound-guided biliary drainage (EUS-BD) and percutaneous trans-hepatic biliary drainage are the feasible options in this scenario. The major advantages of EUS-BD over percutaneous trans-hepatic biliary drainage include a reduction in patient discomfort and internal drainage away from the tumor, thus reducing the possibility of tissue or tumor ingrowth. With innovations, EUS-BD is helpful not only for bilateral communicating MHBO but also for non-communicating systems with bridging hilar stents or isolated right intra-hepatic duct drainage by hepatico-duodenostomy. EUS-guided multi-stent drainage with specially designed cannulas and guidewires has become a reality. A combined approach with endoscopic retrograde cholangiopancreatography for re-intervention, interventional radiology, and intraductal tumor ablative therapies has been reported. Stent migration and bile leakage can be minimized with proper stent selection and technique, and stent blocks can be managed with EUS-guided interventions in a majority of cases. Future comparative studies are required to establish the role of EUS-guided interventions in MHBO as rescue or primary therapy.

The Role of Minimally Invasive Plate Osteosynthesis in Rib Fixation: A Review

  • Bemelman, Michael;van Baal, Mark;Yuan, Jian Zhang;Leenen, Luke
    • Journal of Chest Surgery
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    • v.49 no.1
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    • pp.1-8
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    • 2016
  • More than a century ago, the first scientific report was published about fracture fixation with plates. During the 1950's, open reduction and plate fixation for fractures were standardized by the founders of Arbeitsgemeinschaft $f{\ddot{u}}r$ osteosynthesefragen/Association for the Study of Internal Fixation. Since the introduction of plate fixation for fractures, several plates and screws have been developed, all with their own characteristics. To accomplice more fracture stability, it was thought the bigger the plate, the better. The counter side was a compromised blood supply of the bone, often resulting in bone necrosis and ultimately delayed or non-union. With the search and development of new materials and techniques for fracture fixation, less invasive procedures have become increasingly popular. This resulted in the minimally invasive plate osteosynthesis (MIPO) technique for fracture fixation. With the MIPO technique, procedures could be performed with smaller incisions and thus with less soft tissue damage and a better preserved blood supply. The last 5 years rib fixation has become increasingly popular, rising evidence has becomeavailable suggesting that surgical rib fixation improves outcome of patients with a flail chest or isolated rib fractures. Many surgical approaches for rib fixation have been described in the old literature, however, most of these techniques are obscure nowadays. Currently mostly large incisions with considerable surgical insult are used to stabilize rib fractures. We think that MIPO deserves a place in the surgical treatment of rib fractures. We present the aspects of diagnosis, preoperative planning and operative techniques in regard to MIPO rib fixation.

Studies on Molecular Biological and Immunological Diagnosis of Johne's Disease (분자생물학과 면역학적 방법에 의한 소 요네병 진단의 연구)

  • Kim, Tae-jong;Kim, Yun-sik;Kim, Jae-chun;Yoon, Wha-joong;Lee, Won-chang;Shin, SJ;Chang, YF
    • Korean Journal of Veterinary Research
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    • v.37 no.2
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    • pp.349-358
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    • 1997
  • Mycobacterium paratuberculosis is the etiologic agent of Johne's disease, a chronic inflammatory bowel syndrome in ruminants. The attempts to control or eradicate the disease were severely hampered by the inadequacies of present diagnostic methods. The first purpose of this study was to detect Johne's disease out of 577 cows in the province of Kyunggi, Chungchong, Gangweon and the second purpose was to compare the results of non-absorbed ELISA, absorbed ELISA, PCR, and conventional culture methods. The third purpose was to increase diagnostic specificity, accuracy and rapidity. When non-absorbed ELISA test was conducted with Mycobacterium paratuberculosis antigen, the prevalence of positive was 10.9%. To increase diagnostic specificity, absorbed ELISA test with Mycobacterium phlei was used. In this test, the positive prevalence was 1.7%. For the specific detection of Mycobacterium paratuberculosis, PCR was applied to bacterial culture obtained from fecal samples of cattle. The DNA sequences derived from IS900 were used to prepare DNA primers for detection and identification of Mycobacterium paratuberculosis by PCR. PCR for M paratuberculosis isolated from fecal cultures amplified specific target DNA. PCR was much more rapid than that obtained by conventional culture technique in diagnosis of Johne's disease.

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Results of Protocol-based Perioperative Management in Off-Pump Coronary Artery Bypass Grafting for Patients with Non-dialysis-dependent Chronic Kidney Disease

  • Kim, Jeong-Won;Sim, Hyung Tae;Yoo, Jae Suk;Kim, Dong Jin;Cho, Kwang Ree
    • Journal of Chest Surgery
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    • v.49 no.6
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    • pp.427-434
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    • 2016
  • Background: Recent studies have demonstrated the benefits of off-pump coronary bypass grafting over the on-pump technique in patients with chronic kidney disease (CKD). To further reduce the risk of acute kidney injury and the need for renal replacement therapy, even in patients undergoing off-pump coronary artery bypass grafting, we adopted protocol-based perioperative management for patients with CKD. Methods: From December 2012 to March 2015, 265 patients underwent isolated off-pump coronary artery bypass grafting. To analyze renal function in a stable condition, we excluded 12 dialysis-dependent end stage renal failure and 10 emergency or urgent cases. Among the remaining 243 patients, 208 patients had normal kidney function (normal group), and 35 patients had CKD (CKD group). Minimizing contrast exposure, ensuring adequate hydration, using strict drug dosage adjustment, and optimizing hemodynamic status were key elements of the protocol for the CKD group. Results: The risk of acute kidney injury was about ${\times}3$ higher in the CKD group than in the normal group (p=0.01). Estimated glomerular filtration rates and serum creatinine levels deteriorated until the third postoperative day in the CKD group. However, by adopting protocol-based perioperative management, this transient renal dysfunction recovered to preoperative levels by the fifth postoperative day without requiring renal replacement therapy in all cases. Conclusion: Off-pump coronary bypass surgery combined with this protocol-based perioperative management strategy in patients with non-dialysis-dependent CKD could mostly be performed without renal replacement therapy.