Coupled Sub-Synchronous Vibration Of Lateral And Axial Directions

Case Studypg. 537-55

A Comparison of Manufacturing Methods, Accuracy, Quality Control and Testing Methods a They Relate to High Head Low Flow Impeller Efficiency and Overall Compressor Performance

LectureThis paper presents a detailed analysis and evaluation of impeller efficiency and overall compressor performance as they relate to specific impeller manufacturing methods, manufacturing tolerances, and quality control. The manufacturing process used in the construction of an impeller has a direct influence on the impeller’s performance The authors explain and compare different manufacturing methods and introduce the Taguchi Method Application as an available tool for statistical evaluation of key manufacturing parameters influence on impeller performance. As a best practice, manufacturing techniques for one piece impeller production are presented. In the case of high pressure centrifugal compressor applications with very narrow tip width impellers, and corrosive gas applications requiring special materials, EDM (Electrical Discharge Machining) and ECM (Electrolytic Machining) can be applied as a manufacturing process to improve quality control over conventional manufacturing methods. In response to a compressor performance discrepancy encountered during OEM FAT, a review was initiated into improving quality control and performance prediction based on enhanced impeller manufacturing processes for narrow tip width impellers. In this analysis, two compressor rotors are evaluated and compared; the first using traditional, two piece welded impellers and the second with one piece impellers machined via EDM and ECM. The resulting data from both series of tests suggests a significant improvement in individual impeller performance, as well as overall compressor performance for the single piece impeller compared to the two piece impeller

Train Performance - Evaluation and Monitoring by Torque Meter Applications and Process Gas Compressor / Steam Turbine Train Fouling and Washing Mitigation

LectureThe systematic monitoring and evaluation of turbomachinery is an important diagnostic tool in the execution of a long-term maintenance plan as well as the prevention of unexpected outages due to machinery breakdown. This paper introduces the typical causes of performance deterioration in compressors and steam turbines and the phenomena related to their causes. In addition, this paper also introduces how to evaluate performance, based on site monitoring techniques are explained by combining typical evaluation results with torque measurement and maximum power limit control. Evaluation of these results can determine if deterioration in performance, caused by a change in the internal flow conditions, has occurred. Finally, typical results from on-line washing techniques for compressors and steam turbines will be introduced and the power recovery rate after on-line washing, measured by the torque meter, will be discussed

Investigation Results for Surge Phenomena of Centrifugal Compressor Related with Piping Arrangements and Test Conditions

LectureThe shop performance test of a hydrogen recycle gas compressor for refinery plant was conducted with the suction pressure of 50barA based on ASME PTC-10 Type-2 test. During testing, a surge phenomenon was observed at a flow rate 15 % higher than the predicted surge flow. From the FFT results of the shaft vibration and the pressure pulsation at the discharge of the compressor, the peaks of sub-synchronous components were observed at two frequencies of 2Hz and 30Hz near surge flow. The sub-synchronous vibration at 30Hz was considered to be caused by rotating stall, but the 2Hz was too low to be attributable to rotating stall. As an assumption of the root cause, the acoustic characteristics of shop test loop were checked. The calculated and measured Helmholtz resonance frequency of the shop test loop was in agreement with the sub-synchronous frequency of 2Hz. For further investigation, additional tests were carried out with a fully instrumented test loop. Many different test cases were carried out by changing the suction pressure and piping size, with and without installing a perforated plate near the compressor. The originating flow points of the surge were different in each case. The originating flow point of the surge was small when the suction pressure was high and/or the perforated plate was installed. From the investigation results, it was found that the mode of the acoustic characteristics of test loop was related with the originating flow point of surge. In case the compressor discharge is the node of pressure pulsation, it becomes the anti-node of flow fluctuation. In this case, if the flow approaches surge, the flow fluctuation at the compressor discharge is increased. It transmits to the compressor suction, and it would cause the surge of the compressor. In case the perforated plate was installed near the compressor discharge, the pressure pulsation at the compressor discharge was increased. It decreased the flow fluctuation of the compressor discharge, and the surge became suppressed

Correlation between optic nerve head circulation and visual function before and after anti-VEGF therapy for central retinal vein occlusion : prospective, interventional case series

Background: To determine the correlation between the optic nerve head (ONH) circulation determined by laser speckle flowgraphy and the best-corrected visual acuity or retinal sensitivity before and after intravitreal bevacizumab or ranibizumab for central retinal vein occlusion. Methods: Thirty-one eyes of 31 patients were treated with intravitreal bevacizumab or ranibizumab for macular edema due to a central retinal vein occlusion. The blood flow in the large vessels on the ONH, the best-corrected visual acuity, and retinal sensitivity were measured at the baseline, and at 1, 3, and 6 months after treatment. The arteriovenous passage time on fluorescein angiography was determined. The venous tortuosity index was calculated on color fundus photograph by dividing the length of the tortuous retinal vein by the chord length of the same segment. The blood flow was represented by the mean blur rate (MBR) determined by laser speckle flowgraphy. To exclude the influence of systemic circulation and blood flow in the ONH tissue, the corrected MBR was calculated as MBR of ONH vessel area – MBR of ONH tissue area in the affected eye divided by the vascular MBR – tissue MBR in the unaffected eye. Pearson’s correlation tests were used to determine the significance of correlations between the MBR and the best-corrected visual acuity, retinal sensitivity, arteriovenous passage time, or venous tortuosity index. Results: At the baseline, the corrected MBR was significantly correlated with the arteriovenous passage time and venous tortuosity index (r = -0.807, P < 0.001; r = -0.716, P < 0.001; respectively). The corrected MBR was significantly correlated with the best-corrected visual acuity and retinal sensitivity at the baseline, and at 1, 3, and 6 months (all P < 0.050). The corrected MBR at the baseline was significantly correlated with the best-corrected visual acuity at 6 months (r = -0.651, P < 0.001) and retinal sensitivity at 6 months (r = 0.485, P = 0.005). Conclusions: The pre-treatment blood flow velocity of ONH can be used as a predictive factor for the best-corrected visual acuity and retinal sensitivity after anti-VEGF therapy for central retinal vein occlusion. Trial registration: Trial Registration number: UMIN000009072. Date of registration: 10/15/2012

Offshore-origin warm water inflows toward Totten Ice Shelf, East Antarctica

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Thu. 5 Dec. / 2F Auditorium , National Institute of Polar Researc

Novel quantitative immunohistochemical analysis for evaluating PD-L1 expression with phosphor-integrated dots for predicting the efficacy of patients with cancer treated with immune checkpoint inhibitors

IntroductionProgrammed cell death ligand 1 (PD-L1) expression in tumor tissues is measured as a predictor of the therapeutic efficacy of immune checkpoint inhibitors (ICIs) in many cancer types. PD-L1 expression is evaluated by immunohistochemical staining using 3,3´-diaminobenzidine (DAB) chronogenesis (IHC-DAB); however, quantitative and reproducibility issues remain. We focused on a highly sensitive quantitative immunohistochemical method using phosphor-integrated dots (PIDs), which are fluorescent nanoparticles, and evaluated PD-L1 expression between the PID method and conventional DAB method.MethodsIn total, 155 patients with metastatic or recurrent cancer treated with ICIs were enrolled from four university hospitals. Tumor tissue specimens collected before treatment were subjected to immunohistochemical staining with both the PID and conventional DAB methods to evaluate PD-L1 protein expression.ResultsPD-L1 expression assessed using the PID and DAB methods was positively correlated. We quantified PD-L1 expression using the PID method and calculated PD-L1 PID scores. The PID score was significantly higher in the responder group than in the non-responder group. Survival analysis demonstrated that PD-L1 expression evaluated using the IHC-DAB method was not associated with progression-free survival (PFS) or overall survival (OS). Yet, PFS and OS were strikingly prolonged in the high PD-L1 PID score group.ConclusionQuantification of PD-L1 expression as a PID score was more effective in predicting the treatment efficacy and prognosis of patients with cancer treated with ICIs. The quantitative evaluation of PD-L1 expression using the PID method is a novel strategy for protein detection. It is highly significant that the PID method was able to identify a group of patients with a favorable prognosis who could not be identified by the conventional DAB method

The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search