170,246 research outputs found
The effect of temperature distribution on parabolic triangular-based CPVT system performances: Electrical and thermal perspectives
No full textThe performance of photovoltaic (PV) and photovoltaic-thermal (PVT) systems is affected by environmental parameters and working conditions such as, partial shading, refrigerant and operating temperature. This study focuses on the investigation of the operating conditions and performance of a low concentrated parabolic-trough PVT (CPVT) system. Electro-thermal (electrical and thermal) analysis of the CPVT system was investigated. In the electrical analysis, the effect of series, serial-parallel (SP), total cross-tied (TCT) and grouped connection forms were investigated using a single diode model. In thermal analyses, temperature distribution of the CPVT system was investigated using finite volume methods considering different fluid inlet temperatures. Firstly, thermal analysis was carried out under certain conditions of the CPVT system. Then the obtained temperature distribution was applied to the electrical model. Thus, the electrical and thermal performance of the CPVT system under certain conditions was estimated. Obtained results show that series connection is negligibly better than TCT connections. According to identical mass and pressure and under operating conditions, fluid inlet and outlet temperature differences is 8.77 °C for water. PV module temperature increases up to 110 °C, when fluid inlet temperature is 50 °C for R134a. So, the PV module output power significantly decreases. When the electrical and thermal efficiencies of the CPVT system were evaluated, water obtains better results than the other fluids due to its high specific heat. Therefore, fluid, fluid mass and pressure have to be carefully selected and designed before system's experimental design. Finally, fluid mass should be selected at more and more rates in high temperature applications
Comparison of PV Power Production Estimation Methods Under Non-homogeneous Temperature Distribution for CPVT Systems
No full textThe way to increase energy generation in a standard photovoltaic (PV) or photovoltaic/thermal (PV/T) system is the tracking of the sun and/or concentrating to increase the solar energy coming into the field. As the radiation is increased in both concentrated PV and PV/T systems, both PV power output and PV module temperature increase. The fact that the PV module temperature increases and exceeds the reasonable level reduces the life of solar cells and permanently damages the cells. The way to prevent this is to cool the PV modules. In other words, thermal energy is absorbed by integrating the thermal system. Thus, both electrical and thermal energy needs will be met easily, and a concentrating photovoltaic thermal (CPVT) system produces both electricity and thermal energy from the sun. Electrical and thermal behavior analyzes of CPVT systems are important issues in order to robust and accurate deciding for electrical and thermal power production. In a previous study, finite volume methods were applied for thermal analysis of the CPVT system. Temperature distribution of the PV modules and CPVT surfaces was done. In the numerical analysis; power/temperature coefficient-based method was used for electrical power estimation. In this chapter, power/temperature coefficient-based and five parameter models of PV modules were presented and discussed for forecasting of electrical power production. Decided to PV module temperature in power/temperature coefficient model and temperature distribution applications on diode model were discussed. Power/temperature-based power estimation methods are depending on first, medium, and end PV module temperature. However, different case studies for CPVT electrical power production forecasting methods were investigated. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Performance analysis of a multi crystalline Si photovoltaic module under Mugla climatic conditions in Turkey
No full text0000-0002-4943-6644WOS: 000313134500064Commercially available, a multi crystalline silicon (mc-Si) photovoltaic (PV) module has been monitored outdoors under Mugla climatic conditions in Turkey. Electricity yield of this module is calculated from the uninterruptible measured current-voltage curves from sunrise to sunset during a year. Calculated electricity yield from the measured plane of array or in-plane (POA) irradiation is compared with the calculated electricity from the manufacturer's electrical values of the module and the measured electricity from the photovoltaic system consisting 26 mc-Si PV modules from the same manufacturer. Calculated annual energy rating for the PV system is 1415.79 kW h/kW p and 1414.18 kW h/kW p from the manufacturer data and tested module respectively. The measured energy rating value is 1412.78 kW h/kW p. Comparison of results from this study with those obtained from the measurements show that the average difference in monthly electricity values varies between +/- 12% with an annual average value less than 1% and a performance ratio (PR) of 0.72. (C) 2012 Elsevier Ltd. All rights reserved
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration
No full textAccurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25%) with both low-cost PCB and stable metal-alloy shunts.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
An Article About Albertus C. Van Raalte, Author Unknown, Except for Parts Taken from an Article by Anna C. Post
No full textAn article about Albertus C. Van Raalte, author unknown, except for parts taken from an article by Anna C. Post. The author knew first generation persons in the Holland settlement and therefore, the article has some value.https://digitalcommons.hope.edu/vrp_1890s/1012/thumbnail.jp
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