Search results for "leakage"
showing 10 items of 146 documents
Innovative thermoeconomic diagnosis of multiple faults in air conditioning units: Methodological improvements and increased reliability of results
2013
Abstract Thermoeconomic faults diagnosis of air conditioning units is a pioneeristic approach to detect single or multiple faults and quantify their impact in terms of additional energy consumption. The poor reliability of conventional thermoeconomic approaches has been limiting the interest for practical applications of this technique. In this paper an improved thermoeconomic diagnosis is proposed and applied to a reference 120 kW c air-cooled air conditioning system; a simulator is used to evaluate thermodynamic data under normal and faulty conditions. Four faults are individually or simultaneously imposed: fouling at condenser and evaporator, refrigerant undercharge and compressor valve …
Efficient Monolithic Perovskite/Perovskite Tandem Solar Cells
2016
Thin-film solar cells suffer from various types of recombination, of which leakage current usually dominates at lower voltages. Herein, we demonstrate first a three-order reduction of the shunt loss mechanism in planar methylammonium lead iodide perovskite solar cells by replacing the commonly used hole transport layer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with a better hole-selective polyarylamine. As a result, these cells exhibit superior operation under reduced light conditions, which we demonstrate for the extreme case of moonlight irradiance, at which open-circuit voltages of 530 mV can still be obtained. By the shunt removal we also observe the VOC to dro…
Perimeter leakage current in polymer light emitting diodes
2009
Observation of leakage current paths through the device perimeter in standard poly(phenylene vinylene)-based light-emitting devices is reported. Perimeter leakage currents govern the diode performance in reverse and low positive bias and exhibit an ohmic character. Current density correlates with the perimeter-to-area ratio thus indicating that leakage currents are mainly confined on polymer regions in the vicinity of metallic contact limits (device perimeter). © 2008 Elsevier B.V. All rights reserved.
The effect of oxygenation on the radiation hardness of silicon studied by surface photovoltage method
2002
The effect of oxygenation on the radiation hardness of silicon detectors was studied. Oxygen-enriched and standard float-zone silicon pin-diodes and oxidized samples were processed and irradiated with 15-MeV protons. After the irradiations, the surface photovoltage (SPV) method was applied to extract minority carrier diffusion lengths of the silicon samples. Adding oxygen to silicon was found to improve the radiation hardness of silicon. The effect was visible in minority carrier diffusion lengths as well as in reverse bias leakage currents. The suitability of SPV method for characterizing irradiated silicon samples was proved.
Electrochemical Oxidation of Hf-Nb Alloys as a Valuable Route to Prepare Mixed Oxides of Tailored Dielectric Properties
2018
Metal oxides with high dielectric constant are extensively studied in the frame of substituting SiO2 as gate dielectric in nanoelectronic devices. Here, high-k mixed HfO2/Nb2O5 oxides are prepared by a facile electrochemical route starting from sputtering-deposited Hf–Nb alloys with several compositions. Transmission electron microscopy, grazing incidence X-ray diffraction, and glow discharge optical emission spectroscopy are employed to study the oxide structures, disclosing a crystalline–amorphous transition of the electrochemically prepared oxides by increasing the Nb content. Photo-electrochemical measurements allow the observation of optical transitions ascribed to localized states ins…
Predictive value of IL-6 and IL-10 serum levels in anastomotic leakage in elderly patients undergoing surgery for colorectal cancer
2009
Methods The study group is yet represented by 33 patients: 17 males and 16 females (median age 76, range 70–89). The location of cancer was respectively: 5 (15, 15%) in the rectum, 15 (45, 45%) in the left colon, 11 (33, 33%) in the right colon, 1 (3, 3%) in the transverse colon, 1 (3, 3%) synchronous in the caecum and the sigmoid colon. The associated diseases observed were: chronic obstructive pulmonary disease, hypertension, diabetes mellitus, ischemic heart disease arterial vasculopathy.
Worldwide Techniques and Outcomes in Robot-assisted Minimally Invasive Esophagectomy (RAMIE): Results From the Multicenter International Registry
2022
OBJECTIVE: This international multicenter study by the Upper GI International Robotic Association aimed to gain insight in current techniques and outcomes of RAMIE worldwide.BACKGROUND: Current evidence for RAMIE originates from single-center studies, which may not be generalizable to the international multicenter experience.METHODS: Twenty centers from Europe, Asia, North-America, and South-America participated from 2016 to 2019. Main endpoints included the surgical techniques, clinical outcomes, and early oncological results of ramie.RESULTS: A total of 856 patients undergoing transthoracic RAMIE were included. Robotic surgery was applied for both the thoracic and abdominal phase (45%), o…
PS02.147: MANAGEMENT OF A SIMULTANEOUS HIGH ESOPHAGO-TRACHEAL FISTULA CAUSED BY ESOPHAGEAL STENT DUE TO ANASTOMOTIC LEAKAGE AFTER IVOR-LEWIS ESOPHAGE…
2018
Abstract Background Esophagotracheal perforation is a very severe complication. However, an esophagotracheal perforation caused due to an esophageal stent after anastomotic leakage after ivor-lewis resection, is even more complex and associated with high mortality. Therefore we present a case how we managed a high esophagotracheal perforation and anastomotic leakage after ivor-lewis resection of esophageal cancer, prior treated with neoadjuvant radiochemotherapy. Methods Case report A 71-year old patient was transferred to our center due to an esophagotracheal perforation at the proximal stent—and at 18–20 cm from the front teeth row. The stent had been placed due to anastomotic leakage aft…
P126 HIGH ESOPHAGOTRACHEAL FISTULA DURING STENT TREATMENT OF AN ANASTOMOTIC LEAKAGE AFTER ESOPHAGECTOMY
2019
Abstract Aim We present a case of a 71 year old female with a combined anastomotic leakage after ivor-lewis resection and esophagotracheal perforation. Background & Methods Anastomotic leakage after esophageal resection is still associated with high morbidity and mortality throughout hospitalization. Nowadays there are several methods to accomplish sufficient closure of the anastomotic leakage such as clipping and using fibrin sealant in smaller leakages. Severe insufficiencies are commonly treated using esophageal stents. In our case the use of such a stent (10cm covered) placed to an anastomotic leak following esophagectomy with high intrathoracic anastomosis lead to an esophagotrache…
ABSTRACTS: 9 Phenotype characterization of the anti-inflammatory behavior of decidual endothelial cells
2008
Problem: During pregnancy, an adequate inflammatory control is essential for normal intrauterine foetus development. Vascular endothelium is known to play a critical role in regulation of inflammatory processes. We hypothesize a different ability of decidual endothelial cells (DEC) compared to endothelium from other districts to respond to inflammatory stimuli. Material and Methods: DEC were isolated and activated with inflammatory stimuli and their response in term of adhesion molecules expression, vascular leakage and cytokines production was evaluated. These data were compared to the data obtained with HUVEC and microvascular endothelial cells isolated from human skin (ADMEC) and from …