Experimental assessment and validation of an oil ferrous wear debris sensors family for wind turbine gearboxes

[EN] Purpose - The purpose of this study was to perform a complete experimental assessment of a family of oil ferrous wear debris sensor is performed. The family comprised the original sensor and its re-engineered evolution, which is capable of detecting both amount and size of wear debris particles trapped by the sensor and some predefined oil condition properties. Design/methodology/approach ¿ In this work, the first step was to perform a design of experiments for the sensor validation. A specially defined test rig was implemented, and different ferrous wear debris was collected. For each sensor, two different tests were performed. The first test was called a ¿void test¿, where quantified amounts of debris were collided with the sensor without oil. The second one was a dynamic test, where the sensor was installed in the test rig and different amounts of wear debris were added at a constant rate. In addition, specific tests related with oil properties detection were studied. Findings ¿ The results show excellent correlation of the sensor output signal with the amount of wear debris and a satisfactory detection of debris size in all ranges. Also, the dynamic test presented adequate representativeness, and sensors performed well in this scenario. Practical implications ¿ This paper shows the practical implementation of this type of sensor and the usual detection range and rate of detection for different debris size and quantities. Originality/value ¿ This work has a great utility for maintenance managers and equipment designers to fully understand the potential of this type of sensor and its suitability for the application required.Authors would like to thank Iberdrola Generacion S.A. for their support in this project and Universitat Politecnica de Valencia for its support through contract FPI-S2-2015-1065 of Programa de Apoyo para la Investigacion y Desarrollo (PAID). Additionally, the authors would like to especially thank Daniel Veintimilla for their help in this work.Macian Martinez, V.; Tormos, B.; Miró Mezquita, G.; Rodes, I. (2018). Experimental assessment and validation of an oil ferrous wear debris sensors family for wind turbine gearboxes. Sensor Review. 38(1):84-91. https://doi.org/10.1108/SR-04-2017-0065S8491381Chiou, Y.-C., Lee, R.-T., & Tsai, C.-Y. (1998). An on-line Hall-effect device for monitoring wear particle in oils. Wear, 223(1-2), 44-49. doi:10.1016/s0043-1648(98)00289-0Du, L., & Zhe, J. (2011). A high throughput inductive pulse sensor for online oil debris monitoring. Tribology International, 44(2), 175-179. doi:10.1016/j.triboint.2010.10.022Holmberg, K., Adgar, A., Arnaiz, A., Jantunen, E., Mascolo, J., & Mekid, S. (Eds.). (2010). E-maintenance. doi:10.1007/978-1-84996-205-6Sheng, S. (2013), Report on Wind Turbine Subsystem Reliability - A Survey of Various Databases, NREL/PR-5000-59111

Nitric Oxide-Releasing Aspirin Suppresses NF-κB Signaling in Estrogen Receptor Negative Breast Cancer Cells in Vitro and in Vivo

Estrogen receptor negative (ER(−)) breast cancer is aggressive, responds poorly to current treatments and has a poor prognosis. The NF-κB signaling pathway is implicated in ER(−) tumorigenesis. Aspirin (ASA) is chemopreventive against ER(+) but not for ER(−) breast cancers. Nitric oxide-releasing aspirin (NO-ASA) is a safer ASA where ASA is linked to an NO-releasing moiety through a spacer. In vitro, we investigated anti-proliferation effects of NO-ASA (para- and meta-isomers) against ER(−) breast cancer cells MDA-MB-231 and SK-BR-23, effects on NF-κB signaling, and reactive oxygen species by standard techniques. In vivo, effects of NO-ASA were evaluated in a mouse xenograft model using MDA-MB-231 cells. p-NO-ASA inhibited the growth of MDA-MB-231 and SK-BR-3 cells at 24 h, the respective IC50s were 13 ± 2 and 17 ± 2 μM; ASA had an IC50 of \u3e3000 μM in both cell lines. The IC50s for m-NO-ASA in MDA-MB-231 and SK-BR-3 were 173 ± 15 and 185 ± 12 μM, respectively, therefore, implying p-NO-ASA as a stronger inhibitor of growth p-NO-ASA reduced cell growth by inhibiting proliferation, inducing apoptosis and causing G0/G1 cell cycle block. Activation of NF-κB was inhibited by both isomers as demonstrated by decreases in NF-κB-DNA binding and luciferase activity at 24 h, However, m-NO-ASA produced transient effects at 3 h such as increased NF-κB-DNA-binding, increased levels of nuclear p50, even though both isomers inhibited IκB degradation. Increase in nuclear p50 by m-NO-ASA was associated with translocation of p50 in to the nucleus as observed by immunoflouresence at 3 h. NO-ASA induced reactive oxygen species (ROS) as evidenced by overall increases in both H2DCFDA (2′,7′-dichlorodihydrofluorescein) and DHE (dihydroethidium)-derived fluorescence. Inhibition of ROS by N-acetyl-cysteine reversed the m-NO-ASA-mediated translocation of p50 in to the nucleus. In xenografts, p-NO-ASA inhibited tumor growth by inhibiting proliferation (PCNA and tumor volume), inducing apoptosis (TUNEL positive cells) and reducing NF-κB expression. Both isomers inhibit cancer cells, inhibit NF-κB pathway and induce ROS, and have potential as anticancer compounds

Design of Sectoral Antennas Using a Metallic EBG Structure and Multiple Sources Feeding for Base Station Applications

This work aims to study and design base station antennas with metallic electromagnetic band gap (EBG) materials able to create a sectoral radiation pattern presenting at least a 60∘ beamwidth. The use of metallic structures offers a new approach to industrial partners seeking to reduce costs and facilitate design procedures. A new method allowing the improvement of both the directivity and the bandwidth by using a printed antenna array is studied

Perturbation expansion for 2-D Hubbard model

We develop an efficient method to calculate the third-order corrections to the self-energy of the hole-doped two-dimensional Hubbard model in space-time representation. Using the Dyson equation we evaluate the renormalized spectral function in various parts of the Brillouin zone and find significant modifications with respect to the second-order theory even for rather small values of the coupling constant U. The spectral function becomes unphysical for $U \simeq W$, where W is the half-width of the conduction band. Close to the Fermi surface and for U<W, the single-particle spectral weight is reduced in a finite energy interval around the Fermi energy. The increase of U opens a gap between the occupied and unoccupied parts of the spectral function.Comment: 17 pages, 11 Postscript figures, Phys. Rev. B, accepte

Transcatheter Aortic Valve Implantation in Dialysis Patients

Background/Aims: Transcatheter aortic valve implantation (TAVI) has emerged as a new therapeutic option for high-risk patients. However, dialysis patients were excluded from all previous studies. The aim of this study is to compare the outcomes of TAVI for dialysis patients with those for patients with chronic kidney disease (CKD) stages 3 and 4 and to compare TAVI with open surgery in dialysis patients. Methods: Part I: comparison of 10 patients on chronic hemodialysis with 116 patients with non-dialysis-dependent CKD undergoing TAVI. Part II: comparison of transcatheter (n = 15) with open surgical (n = 24) aortic valve replacement in dialysis patients. Results: Part I: dialysis patients were significantly younger (72.3 vs. 82.0 years; p < 0.01). Hospital stay was significantly longer in dialysis patients (21.8 vs. 12.1 days; p = 0.01). Overall 30-day mortality was 3.17%, with no deaths among dialysis patients. Six-month survival rates were similar (log-rank p = 0.935). Part II: patient age was comparable (66.5 vs. 69.5 years; p = 0.42). Patients in the surgical group tended to stay longer in hospital than TAVI patients (29.5 vs. 22.5 days; p = 0.35). Conclusion: TAVI is a safe procedure in patients on chronic hemodialysis. Until new data become available, we find no compelling reason to refuse these patients TAVI. Copyright (C) 2012 S. Karger AG, Base

Incidence, Predictors, and Prognostic Impact of Late Bleeding Complications After Transcatheter Aortic Valve Replacement

AbstractBackgroundThe incidence and prognostic impact of late bleeding complications after transcatheter aortic valve replacement (TAVR) are unknown.ObjectivesThe aim of this study was to identify the incidence, predictors, and prognostic impact of major late bleeding complications (MLBCs) (≥30 days) after TAVR.MethodsClinical and echocardiographic outcomes of patients who underwent TAVR within the randomized cohorts and continued access registries in the PARTNER (Placement of Aortic Transcatheter Valves) trial were analyzed after stratifying by the occurrence of MLBCs. Predictors of MLBCs and their association with 30-day to 1-year mortality were assessed.ResultsAmong 2,401 patients who underwent TAVR and survived to 30 days, MLBCs occurred in 142 (5.9%) at a median time of 132 days (interquartile range: 71 to 230 days) after the index procedure. Gastrointestinal complications (n = 58 [40.8%]), neurological complications (n = 22 [15.5%]), and traumatic falls (n = 11 [7.8%]) were identified as the most frequent types of MLBCs. Independent predictors of MLBCs were the presence of low hemoglobin at baseline, atrial fibrillation or flutter at baseline or 30 days, the presence of moderate or severe paravalvular leak at 30 days, and greater left ventricular mass at 30 days. MLBCs were identified as a strong independent predictor of mortality between 30 days and 1 year (adjusted hazard ratio: 3.91; 95% confidence interval: 2.67 to 5.71; p < 0.001).ConclusionsMLBCs after TAVR were frequent and associated with increased mortality. Better individualized and risk-adjusted antithrombotic therapy after TAVR is urgently needed in this high-risk population. (THE PARTNER TRIAL: Placement of AoRTic TraNscathetER Valve Trial; NCT00530894

Acute kidney injury following transcatheter aortic valve implantation: predictive factors, prognostic value, and comparison with surgical aortic valve replacement

Aims: Very few data exist on the occurrence of acute kidney injury (AKI) associated with transcatheter aortic valve implantation (TAVI). The objectives of the present study were (i) to determine the incidence, predictive factors, and prognostic value of AKI following TAVI, and (ii) to compare the occurrence of AKI in TAVI vs. surgical aortic valve replacement (SAVR) in patients with pre-procedural chronic kidney disease (CKD). Methods and results: A total of 213 patients (mean age 82 ± 8 years) undergoing TAVI for the treatment of severe aortic stenosis were included in the study. Acute kidney injury was defined as a reduction of >25% in estimated glomerular filtration rate (eGFR) within 48 h following the procedure or the need for haemodialysis during index hospitalization. Those patients with pre-procedural CKD (eGFR <60 mL/min/1.73 m2, n = 119) were compared with 104 contemporary patients with CKD who underwent isolated SAVR. The incidence of AKI following TAVI was 11.7%, with 1.4% of the patients requiring haemodialysis. Predictive factors of AKI were hypertension (OR: 4.66; 95% CI: 1.04–20.87), chronic obstructive pulmonary disease (OR: 2.64, 95% CI: 1.10–6.36), and peri-operative blood transfusion (OR: 3.47, 95% CI: 1.30–9.29). Twenty-one patients (9.8%) died during index hospitalization, and the logistic EuroSCORE (OR: 1.03 for each increase of 1%; 95% CI: 1.01–1.06) and occurrence of AKI (OR: 4.14, 95% CI: 1.42–12.13) were identified as independent predictors of postoperative mortality. Patients with CKD who underwent TAVI were older, had a higher logistic EuroSCORE and lower pre-procedural eGFR values compared with those who underwent SAVR (P < 0.0001 for all). The incidence of AKI was lower (P = 0.001; P = 0.014 after propensity score adjustment) in CKD patients who underwent TAVI (9.2%, need for haemodialysis: 2.5%) compared with those who underwent SAVR (25.9%, need for haemodialysis: 8.7%). Conclusion: Acute kidney injury occurred in 11.7% of the patients following TAVI and was associated with a greater than four-fold increase in the risk of postoperative mortality. Hypertension, chronic obstructive pulmonary disease, and blood transfusion were predictive factors of AKI. In those patients with pre-procedural CKD, TAVI was associated with a significant reduction of AKI compared with SAVR

The value of international volunteers experience to the NHS.

BACKGROUND: Global Engagement works with health partnerships to establish workforce and educational translation on a global scale to support the National Health Service (NHS). There is growing evidence on how international experiences (through volunteering, exchanges and placements) benefit the NHS through an innovative workforce that develops international best practice and promotes lifelong learning. Most of this evidence has been captured though surveys to returned international volunteers. However, there is limited evidence about how to quantify the value that returned international healthcare volunteers bring back to their country of residence. METHODS: This paper identifies the various benefits to the NHS from returned international healthcare volunteers. The outcomes from returned international volunteers, which have been identified as relevant form a NHS perspective, are linked to three key areas in a multisector analytical framework used by the World Bank to evaluate labour market programmes: (1) Investment climate and Infrastructure, (2) Labor market regulations and institutions, and (3) Education and skills development. The monetary value of these outcomes is quantified through productivity indices which capture the economic value that the achievement of these outcomes have on the quality of the NHS labor force. This model is applied to a dataset of international volunteers provided by the Global Engagement health partnerships. RESULTS: The results suggest that international volunteering generates average productivity gains of up to 37% for doctors and up to 62% for nurses. Average productivity gains estimated from health partnerships data vary depending on duration of volunteering periods and occupational category mix. CONCLUSIONS: Our analysis offers a value for money rationale for international volunteering programmes purely from a domestic and NHS perspective. The valuation method considers only one of the aims of international volunteering programmes: the development of the existing and future NHS workforce. Broader benefits for health system strengthening at a global level are acknowledged but not accounted for. Overall, we conclude that if the acquisition of volunteering outcomes is realised, the NHS can accrue a productivity increase of between 24 and 41% per volunteer, with a value ranging from £13,215 to £25,934 per volunteer.HEE and the Global Engagement directorat

MIMO-OFDM WDM PON with DM-VCSEL for femtocells application

Globalization, rapid technological changes, and growing competition not only facilitate but also make the supply chain more complex and fragile. Any disruption can disturb many organizations and even the whole system. There are many theories and frameworks that present a solution but no study is available that theoretically development framework for supply chain risk management. The focus of this study is to develop a novel framework for identifying the potential risks and assessment of their effects on supply chain performance. Additionally, evaluate the role of supply chain interaction in risk mitigation and performance improvement in Malaysian manufacturing. This is a conceptual paper, systematic as well as content analysis have been done for the literature review. For future study, there is a need to empirically verification of this theoretical framework. The proposed methodology to achieve this framework is; a questionnaire will be developed from a pool and will be validated by exploratory view for risk identification. This questionnaire will be distributed among Malaysian manufacturing and data will be analyzed through Structural Equation Modelling (SEM) for risk assessment and mitigation. The theoretical contribution of this study is support of the theory of swift, even flow as underpinning theory and information processing theory as supportive theory