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[IEEE 2018 4th International Conference on Renewable Energies for Developing Countries (REDEC) - Beirut, Lebanon (2018.11.1-2018.11.2)] 2018 4th International Conference on Renewable Energies for Developing Countries (REDEC) - Modeling, P&O MPPT and PI controls and performance analysis of PV/Energy storage hybrid power system
摘要： The variable nature of renewable energy sources, coupled with unpredictable changes in load, requires the simultaneous implementation of high power and high energy density storage systems. This work addresses dynamic modeling, a PV/Batteries/Ultra capacitor hybrid energy system connected to a DC load in a remote house located around the town of Rouyn Noranda (Quebec-Canada) during one day in winter period. The P&O MPPT control is used to extract the maximum power of a photovoltaic generator which is considered as the main energy source of the hybrid system. In this paper, batteries and ultra-capacitors (UC) are serving as an energy storage system (ESS) and a main source in winter period. The UC are used for facing high frequency variations of the load, such as in transient state, while the batteries are in charge of slow load/source variations. Classical control of battery current and ultra-capacitor current allows choosing the suitable storage element in order to face correctly the production/consummation variations. Classical PI control strategy is proposed in manner to stabilize the DC bus voltage by controlling the attached DC/DC bidirectional converters. Simulations during 00 AM to 3 PM (during a snowy day) are carried out using Matlab/Simulink which confirm the good performances of the hybrid system and associated control systems.
关键词： energy storage system,performance analysis,Photovoltaic,hybrid energy system
更新于2025-09-23 15:22:29
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Green method by diffuse reflectance infrared spectroscopy and spectral region selection for the quantification of sulphamethoxazole and trimethoprim in pharmaceutical formulations
摘要： An alternative method for the quantification of sulphametoxazole (SMZ) and trimethoprim (TMP) using diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) and partial least square regression (PLS) was developed. Interval Partial Least Square (iPLS) and Synergy Partial Least Square (siPLS) were applied to select a spectral range that provided the lowest prediction error in comparison to the full-spectrum model. Fifteen commercial tablet formulations and forty-nine synthetic samples were used. The ranges of concentration considered were 400 to 900 mg g-1 SMZ and 80 to 240 mg g-1 TMP. Spectral data were recorded between 600 and 4000 cm-1 with a 4 cm-1 resolution by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The proposed procedure was compared to high performance liquid chromatography (HPLC). The results obtained from the root mean square error of prediction (RMSEP), during the validation of the models for samples of sulphamethoxazole (SMZ) and trimethoprim (TMP) using siPLS, demonstrate that this approach is a valid technique for use in quantitative analysis of pharmaceutical formulations. The selected interval algorithm allowed building regression models with minor errors when compared to the full spectrum PLS model. A RMSEP of 13.03 mg g-1 for SMZ and 4.88 mg g-1 for TMP was obtained after the selection the best spectral regions by siPLS.
关键词： green analytical method,diffuse reflectance infrared Fourier transform spectroscopy,interval partial least squares (iPLS),chemometrics,synergy partial least squares (siPLS),high performance liquid chromatography
更新于2025-09-23 15:22:29
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Smart lighting as basic building block of smart city: An energy performance comparative case study
摘要： The aim of this work is to simulate and compare the energy savings potentially applicable to the consumption data of the Smart Street pilot system located at the ENEA Casaccia R.C. (Rome). The astronomical lighting system energy consumption (baseline) is compared to the simulation of a pre-defined regulation: it allows the lights dimming (and therefore a reduction of consumptions) based on a statistics average of the traffic flow rate, differentiated according to the day of the week. Then the baseline consumption is compared to the simulation of an adaptive configuration based on the traffic flow rate.
关键词： pre-defined regulation,adaptive regulation,energy performance,TAI,smart street,smart lighting,smart city
更新于2025-09-23 15:22:29
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Performance characteristics of the digital Biograph Vision PET/CT system
摘要： This study evaluates the performance of the Siemens Biograph Vision digital PET/CT system (Siemens Healthineers, Knoxville, USA) according to the NEMA NU 2‐2012 standard (published by the National Electrical Manufacturers Association (NEMA)) to allow for a reliable, reproducible, and inter‐system comparable performance measurement. Methods: The new digital PET/CT features silicon photomultiplier (SiPM)‐based detectors with 3.2 mm lutetium oxyorthosilicate (LSO) crystals and full coverage of the scintillator area. The PET components incorporate eight rings of 38 detector blocks and each block contains 4x2 mini‐blocks. Each mini‐block consists of a 5x5 LSO‐array of 3.2x3.2x20 mm crystals coupled to a SiPM‐array of 16x16 mm, resulting in an axial field of view (FOV) of 26.1 cm. In this study PET/CT system performance will be evaluated conform the NEMA NU 2‐2012 standard with additional measurements described in the new NEMA NU 2‐2018 standard. Spatial resolution, sensitivity, count‐rate performance, accuracy of attenuation and scatter correction, Time‐of‐Flight (TOF) performance, and image quality will be determined. Measurements will be directly compared to results from its predecessor, the Biograph mCT Flow, using existing literature. Moreover, feasibility to comply with the European Association of Nuclear Medicine (EANM) Research Ltd (EARL) criteria will be evaluated and some illustrative patient PET images will be shown. Results: The Biograph Vision shows a transverse (resp. axial) spatial resolution at Full Width Half Maximum (FWHM) of 3.6 mm (resp. 3.5 mm) at 1 cm offset of the center of the FOV (measured with a 22Na 0.25 mm point‐source), a NEMA sensitivity of 16.4 kcps/MBq, and a NEMA peak NECR of 306 kcps at 32 kBq/mL. TOF resolution varied from 210 to 215 as count‐rate increased up to the peak NECR. The overall image contrast seen with the NEMA image quality phantom ranged from 77.2% to 89.8%. Furthermore, the system was able to comply with the current and future EARL performance criteria. Conclusions: The Biograph Vision outperforms the analog Biograph mCT Flow and the system is able to meet European harmonizing performance standards.
关键词： PET/CT,Digital detectors,NEMA,performance evaluation
更新于2025-09-23 15:22:29
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A new TRNSYS type for thermosiphon flat-plate solar thermal collectors: validation and optimization procedure
摘要： This paper presents a new TRNSYS Type (called Type 99) which can be used for the energy assessment of thermosiphon Flat-Plate solar thermal Collectors (FPCs) for water heating. The accuracy of this new type is higher than the standard type (Type 45a) available in TRNSYS library, since the density and specific heat of water are estimated according to the operating fluid temperature. The results of a suitable experimental campaign are also presented for different commercial FPCs system layouts. The developed Type 99 is successfully validated, proven by the very good agreement achieved between the simulation and experimental results. By the new Type 99 a suitable Design of Experiment (DoE) analysis is carried out with the aim to assess the design and operating parameters mostly affecting the energy and economic performance of two types of FPCs. Specifically, collector pipe diameters, slope, storage tank volume, and thermal insulation thickness are investigated. The analysis is carried out for three case studies which refer to residential Domestic Hot Water (DHW) production applications and to three different European weather zones (Freiburg, Naples and Larnaca). For these case studies an optimization procedure is also carried out by varying the same design and operating parameters for two different objective functions: best energy behaviour [maximum Primary Energy Saving (PES)] and best economic performance [minimum Simple Pay Back (SPB)]. Interesting novel design criteria and encouraging economic results are obtained.
关键词： economic assessment,DoE analysis,Building solar thermal systems,dynamic energy performance analysis,experimental validation
更新于2025-09-23 15:22:29
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Microwave transmission performance of fused silica ceramics in microwave high-temperature heating
摘要： Compared with traditional heating methods, microwave heating is widely used in many industrial heating fields because of its advantages, such as material-selective heating, volumetric heating and high-efficiency heating. However, previous studies have shown that the heating mode depends on the transmission performance of refractory insulation materials. In this study, a commonly used refractory material (fused silica ceramics) for microwave heating was studied, according to the law of electromagnetic wave propagation in a single-layer plate, the power transmission coefficient (PTC) of the material at different thickness, temperature and frequency (915 MHz and 2360 MHz) was calculated and analysed, in order to design the refractory structure which has good microwave transmission performance in the whole microwave heating process. The results show that the transmission performance of fused silica ceramics fluctuates regularly with increasing thickness, and there are several microwave transmission peaks in the PTC patterns, the thicknesses corresponding to the transmission peaks at frequency 2360 MHz are in order 0.033 m, 0.065 m and 0.098 m; as the temperature increases, the position of the transmission peaks will shift to a smaller thickness, the transmission performance of fused silica ceramics decreases slightly with increasing temperature. Comparing the transmission performance of mullite, alumina (Al2O3) and fused silica ceramics, it was found that the fused silica ceramics have excellent transmission properties; especially it is at high temperature. The results of this study can provide guidance for the selection of refractory structure materials and sizes as well as the optimization of heating process parameters in high-temperature microwave heating.
关键词： A. Microwave heating,D. Transmission performance,B. Fused silica ceramic,C. High temperature wave transmitting material
更新于2025-09-23 15:22:29
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Annual performance analysis and optimization of a solar tower aided coal-fired power plant
摘要： The integration of solar energy into coal-fired power plants has been proven as a potential approach in the utilization of solar energy to reduce coal consumption. Moreover, solar augmentation offers low cost and low risk alternatives to stand-alone solar thermal power plants. In this study, the annual performance of a solar tower aided coal-fired power (STACP) system is investigated, and the influence of thermal storage system capacity on the annual solar generating power and annual solar-to-electricity efficiency is explored. The thermal storage system capacity is optimized to obtain the lowest levelized cost of electricity (LCOE). At the same time, the influence and sensitivity of several important economic factors are explored and assessed. Results demonstrate that compared to a coal-fired power system, the reduction in the annual average coal consumption rate of the STACP system with high direct normal irradiance (DNI), medium DNI, and low DNI are 5.79, 4.52, and 3.22 g/kWh, respectively. At a minimum, the annual coal consumption can be reduced by 14,000 t in a 600 MWe power generation unit. Because the same solar field is considered under different DNI conditions, the LCOE in the high DNI, medium DNI, and low DNI scenarios are all fairly similar (6.37, 6.40, and 6.41 ￠/kWh, respectively). When the solar multiple is 3.0, the optimal thermal storage capacity of the STACP system, with high, medium, and low DNIs are 6.73, 4.42, and 2.21 h, respectively. The sensitivity analysis shows that the change in economic parameters exerts more influence on the STACP system with the high DNI compared with the other two scenarios.
关键词： Thermal energy storage capacity,Solar multiple,Annual performance,Optimization,Solar tower aided coal-fired power plant
更新于2025-09-23 15:22:29
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Enhancing the performance of photo-bioelectrochemical fuel cell using graphene oxide/cobalt/polypyrrole composite modified photo-biocathode in the presence of antibiotic
摘要： Photo-bioelectrochemical fuel cell (PBFC) holds a great potential to harvest sustainable electrical energy from wastewater, but low power output limits its applications due to poor electrochemical performance of photo-biocathode. Additionally, antibiotics are ubiquitous in wastewater streams, but little is known regarding their effects on photo-biocathode performance of the PBFC. This study attempted to increase power output of PBFC through improvement of the photo-biocathode performance by modifying the biocathode with graphene oxide/cobalt/polypyrrole (GO/Co/PPy) composite in the presence of oxytetracycline. The GO/Co/PPy composite modified electrode fabricated by one-step electropolymerization method exhibited more excellent catalytic activity toward oxygen reduction compared to Co-alone and Co/PPy modified electrode. The PBFC with GO/Co/PPy composite modified biocathode produced a maximum power density of 19 mW/m2, which was almost 4-fold higher than that produced with the bare biocathode (4.9 mW/m2) due to improved bio-electrocatalytic performance of the bicathode by the GO/Co/PPy composite. The maximum power density of the PBFC was further increased 4.6 (105.5 mW/m2), 3.7 (88.7 mW/m2), 2.9 (74.6 mW/m2) and 1.9 (56 mW/m2) fold by exposure to 5, 10, 20, and 50 mg/L OTC, respectively. The further increases in power was due to reduced cathode's charge transfer resistance using degradation products of OTC as mediators and OTC-stimulated growth of species with extracellular electron transfer ability. However, the photosynthesis and growth of alga was negatively affected by OTC concentration higher than 10 mg/L, resulting performance deterioration of bicathode.
关键词： Photo-bioelectrochemical fuel cell,Electrode modification,Oxytetracycline,Performance improvement,Power generation
更新于2025-09-23 15:22:29
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Enhanced dielectric permittivity in surface-modified graphene/PVDF composites prepared by an electrospinning-hot pressing method
摘要： In the present work, the surface-modified graphene (SMG)/poly(vinylidene fluoride) (PVDF) fibrous membranes obtained from the electrospinning were treated by the hot pressing in the laminating mode to form the SMG/PVDF composites. The SMG was prepared by subjecting the graphene oxide to silane modification, NaBH4 reduction, and PVDF grafting in sequence. The successful surface modification of graphene was confirmed by TEM, XPS, Raman spectroscopy, FTIR, WAXD, and TGA. Furthermore, the structures of SMG/PVDF composites fabricated by the electrospinning-hot pressing method were studied by SEM, FTIR, and WAXD, which exhibited the well dispersion of SMG in the PVDF matrix. Finally, the investigation showed that the dielectric permittivities of SMG/PVDF composites increased with the SMG content, which were significantly higher than that of pristine PVDF. The dielectric permittivity of SMG (16 wt.%)/PVDF composite (83.8) at 1000 Hz was found to be ten-fold that of the corresponding value of pristine PVDF (8.3) with a relatively low dielectric loss factor (0.34) and a relatively high thermal conductivity (0.679 W/mK).
关键词： surface-modified graphene/PVDF composite,thermal conductivity.,electrospinning-hot pressing method,dielectric performance
更新于2025-09-23 15:22:29
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Facile Synthesis of g-C3N4/CdWO4 with Excellent Photocatalytic Performance for the Degradation of Minocycline
摘要： A novel g-C3N4/CdWO4 composite was formed by hydrothermal process and utilized for the removal of Minocycline (MC) antibiotic under visible light exposure. The XRD patterns of synthesized sample reveal the pure crystalline structure and phase of g-C3N4/CdWO4. The SEM images of g-C3N4/CdWO4 showed regular short rod structure with diameter in the range of 20-60 nm. These images also showed that the g-C3N4/CdWO4 structure has well contacted surfaces which enhanced the interfacial transfer of charge as a result of which the performance of photocatalyst was improved. The energy dispersive spectroscopy (EDS) images of g-C3N4, CdWO4 and g-C3N4/CdWO4 conclude that there were no impurities in the synthesized samples. SEM and EDS results confirm the interface interaction develop between g-C3N4 and CdWO4 due to hybridization. The FTIR spectrum of composite showed that the composite formed had extensively conjugated system and the band gap energies calculated for CdWO4, g-C3N4 and g-C3N4/CdWO4 were 3.31 eV, 2.67 eV and 2.71 eV respectively. A remarkable drop in photoluminescence intensity of g-C3N4/CdWO4 was observed as compared to pure g-C3N4 and CdWO4 which led to lower recombination rate of photo-induced charge carriers and hence a higher photocatalytic performance for the degradation of minocycline under visible-light irradiation.
关键词： Photocatalytic Performance,Photocatalyst,Recombination Rate,Charge Carries,minocycline
更新于2025-09-23 15:22:29