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Rapid synthesis of ZnO nanoparticles by waste thyme (Thymus vulgaris L.)
摘要： Synthesis of nanoparticles by utilizing microorganisms and plants in green methods is a feasible procedure. This method can be used instead of chemical procedures as an eco-friendly procedure. Antibacterial activity of zinc oxide nanoparticles as one of the best multifunctional nanoparticles is well known. In this study, ZnO nanoparticles were produced by waste thyme (Thymus vulgaris L.) extract. SEM, XRD, UV–Vis, visual analysis and FTIR spectroscopic techniques were used for characterizing ZnO nanoparticles. The absorption of wavelengths of the UV–Vis in the region of 290–320 nm confirmed the formation of zinc oxide nanoparticles. The average size of ZnO nanoparticles was estimated 10–35 nm by SEM technique. An eco-friendly method for the synthesis of ZnO nanoparticles can be used in which the waste thyme extract is used as a stabilizing agent. Therefore, the use of waste thyme extract is an alternative to the chemical methods. Biological methods are rapid, green, economical and simple to perform.
关键词： Medicinal plants,SEM,ZnO nanoparticles,UV–Vis,Green chemistry,XRD
更新于2025-09-11 14:15:04
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[IEEE 2018 International conference on computation of power, energy, Information and Communication (ICCPEIC) - Chennai, India (2018.3.28-2018.3.29)] 2018 Internat2018 International Conference on Computation of Power, Energy, Information and Communication (ICCPEIC)ional conference on computation of power, energy, Information and Communication (ICCPEIC) - Modelling and Control of BESS for Solar Integration for PV Ramp Rate Control
摘要： PV power varies with the passing of clouds; these variations can affect power quality and system uniformity. PV system is combining with a storage device to mitigate the variations in power. During the fast movement of clouds causes sudden changes in power. Sudden changes can limit through ramp rate control. In this work employing a ramp rate control with energy storage system is capable of maintaining the system stability. This work is aimed to design a battery-based storage system integration with considered 500 kW solar photovoltaic power plant using ramp rate control method. The control scheme is tested and validated using MATLAB/Simulink environment.
关键词： solar PV,Power fluctuations smoothing,energy storage,battery,grid-connected PV plants,ramp rate control
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Estimation Model for Dust-Retention Content of Main Green Plants in South China Based on the Red Edge of Reflectance
摘要： Estimating dust-retention content (DRC) on plants leaves is important to the protection and improvement of the atmospheric environment, which can be helpful to the human health and social development. Due to lacking of well-used estimation model, the current studies about dust-retention based on remote sensing are scarce. This paper aims to establish an estimation model for DRC of main green plants based on 56 in situ samples collected in 2014-2016 from Guangzhou, South China. After pre-processing and laboratory analysis, the correlation coefficient between leaf reflectance spectral data and DRC was calculated under MATLAB environment. The results showed that the relationship between red edge (720 nm) of reflectance spectra and DRC is relatively higher. Therefore, a model for estimating DRC based on red edge position was established. It was found that the exponential model showed a high calibration accuracy (DRC: 0.019-1.1 g/m2, R2=0.71, N=40, P-value < 0.001) and had an acceptable validation accuracy (DRC: 0.154-0.978 g/m2, RMSE = 0.157 g/m2, MRE=33.8%, N=16). Although the red edge of vegetation was generally used to monitor the health status of plants, the results of this study indicated that red edge of reflectance can be applied for estimating the DRC on plants leaves as well. Based on the DRC retrieval model, there is potential to monitor and estimate the dynamic changes of dust-retention in a large region from multi-source satellite and unnamed aerial vehicle platform.
关键词： dust-retention content,green plants,red edge,South China,estimation model
更新于2025-09-10 09:29:36
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Electromagnetic Acoustic Transducers Applied to High Temperature Plates for Potential Use in the Solar Thermal Industry
摘要： Concentrated Solar Plants (CSPs) are used in solar thermal industry for collecting and converting sunlight into electricity. Parabolic trough CSPs are the most widely used type of CSP and an absorber tube is an essential part of them. The hostile operating environment of the absorber tubes, such as high temperatures (400–550 °C), from creep, contraction/expansion, and vibrations, may lead them to suffer thermo-mechanical fatigue, and hot corrosion. Hence, their condition monitoring is of crucial importance and a very challenging task as well. Electromagnetic Acoustic Transducers (EMATs) are a promising, non-contact technology of transducers that has the potential to be used for the inspection of large structures at high temperatures by exciting Guided Waves. In this paper, a study regarding the potential use of EMATs in this application and their performance at high temperature is presented. A Periodic Permanent Magnet (PPM) EMAT with a racetrack coil, designed to excite Shear Horizontal waves (SH0), has been theoretically and experimentally evaluated at both room and high temperatures.
关键词： non-destructive testing,high temperatures,Electromagnetic Acoustic Transducer (EMAT),solar thermal plants,guided waves
更新于2025-09-09 09:28:46
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Remote sensing of forest health and vitality: a South African perspective
摘要： Commercial forestry plantations are an important and valuable segment of the South African economy and forest managers are required to maximise and sustain forest productivity. However, various factors such as the outbreak of damaging agents are constantly hampering forest health and thus decrease productivity. It is therefore important to detect the presence and spread of these agents within plantation forests, a task efficiently achieved using remote sensing technology. A wide assortment of sensors with varying resolutions are available and have been extensively used for this purpose. This paper reviews the current status of remote sensing of forest health in South Africa by providing insight on the latest developments on the use of the technology in forest plantations. A systematic search was executed on Google Scholar, ScienceDirect? and EBSCOhost? databases that identified 627 articles of which 29 made reference to remote sensing of forest health in South Africa. Four key results were found: (1) the latest technology is capable of detecting and monitoring forest health with great accuracy, especially with the adoption of machine learning methods; (2) studies employing remote sensing to characterise forest health have burgeoned since 2006 with even more applying hyperspectral data; (3) most studies were spatially concentrated in the KwaZulu-Natal Midlands region around Pietermaritzburg with only a few over the Western Cape; and (4) the remote detection of pest outbreaks and pathogens have received much attention followed by alien invasive plants and a few studies directed to fragmentation. Present and future partnerships may open up opportunities for exploiting remote sensing further; this should address growing expectations from government and industry for more detailed and accurate information concerning the health and condition of South Africa’s plantation forests.
关键词： fragmentation,pest and pathogens,remote sensing,alien invasive plants,forest health
更新于2025-09-09 09:28:46
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A new methodology for the determination of silicon in plants by wavelength dispersive X-ray fluorescence
摘要： Silicon is an important element for plants at their structure and physiology and plays an important role in bone mineralization and soft tissue development in human beings. Furthermore, its determination is being requested more frequently due to nutritional requirements. However, the methods found in the literature to determine silicon in this type of samples require a sample preparation step, which makes them time‐consuming and provides high uncertainties. In this paper, a method for the determination of silicon in plants by wavelength dispersive X‐ray fluorescence (WD‐XRF) spectrometry has been developed. Horsetail (Equisetum arvense L.) and nettle leaf (Urtica dioica) have been used as a source of silicon due to its medical use. Sample preparation involved calcining the sample at 700°C and preparing fused beads from the calcined sample. Calibration standards for WD‐XRF measurement were prepared by mixing certified reference materials and chemical products to reproduce the samples matrix. The linear range for silicon concentration ranges from 6 to 55 wt% SiO2. The validation of the method was performed measuring a reference material (NCS DC73349 Bush branches and leaves) and comparing the results obtained by WD‐XRF with those obtained by an independent method by atomic absorption spectrometry. The developed methodology is rapid and accurate, provides low uncertainties, and is environmentally friendly, as it does require the use of less hazardous reagents.
关键词： silicon,WD‐XRF,wavelength dispersive X‐ray fluorescence,sample preparation,plants,fused beads
更新于2025-09-04 15:30:14
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Raman Spectroscopy and Applications || Raman Mapping: Emerging Applications
摘要： Raman mapping is a noninvasive, label‐free technique with high chemical specificity and high potential to become a leading method in biological and biomedical applications. As opposed to Raman spectroscopy, which provides discrete chemical information at distinct positions within the sample, Raman mapping provides chemical information coupled with spatial information. The laser spot scans the investigated sample area with a preset step size and acquires Raman spectra pixel by pixel. The Raman spectra are then discriminated from each other by chemometric analysis, and the end result is a false color map, an image of the sample that contains highly precise structural and chemical information. Raman imaging has been successfully used for label‐free investigations at cellular and subcellular level. Cell compartments, cell responses to drugs and different stages of the cell cycle from the stem cell to the completely differentiated cell were successfully distinguished. This technique is also able to differentiate between healthy and cancer cells, indicating great potential for replacing conventional cancer detection tools with Raman detection in the future.
关键词： plants,algae,cells,medical diagnosis,tissues,Raman imaging,Raman mapping,Raman spectroscopy
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - The design of dust barriers to reduce collector mirror soiling in CSP plants
摘要： In this work we investigate, design, and evaluate a number of dust barrier designs that would be appropriate to reduce soiling of glass mirror solar collectors in the solar field of an existing CSP plant. The principal objective was to reduce the amount of soiling (and hence the amount of cleaning water consumed) by 50% in comparison with current cleaning procedures (considering particles of size >25μm). “Fluent” CFD software was used to model of a range of potential dust barrier shapes, sizes, and porosities. Airflows and wind loadings were analyzed in this way. A number of potential designs were then taken forward for experimental validation. Initial validation involved wind tunnel evaluation of a small number of potential designs, using a new wind tunnel specifically designed and built for this project. Larger-scale outdoor validation was carried out both at Cranfield University in the UK and at CIEMAT-PSA (Plataforma Solar de Almeria) in Spain. Initial results were independent of location and barrier shape and showed that the percentage of particles that were stopped completely or travelled less than 1m beyond the barrier was in the range 45.8 ± 5%.
关键词： soiling,dust barriers,CSP plants,wind tunnel testing,CFD modelling
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Revisiting field layout designs for large STE tower plants
摘要： Solar Thermal Electricity (STE/CSP) Tower Plants suffer a reduction on the solar field efficiency when their size increases. As plant-size is an important driver for the reduction of generation costs of STE plants - due to the relative impact of the power block and the O&M costs - plant-size could be a big disadvantage for tower plants. To cope with this issue a new rationale is proposed for designing the new generation of large tower plants. This paper demonstrates the performance benefits of the multitower approach, with single storage and power block and with northern fields versus large surrounded type; all at different latitudes and different atmospheric transmittance conditions. Field sizes of 50 MW equivalent - for plants with medium storage - appears to be a kind of standard for locations with relatively clear atmosphere while, in hazy locations, smaller sizes around 30 MW should be preferred. Besides the efficiency advantages, standardizing the designs and making them modular could also contribute to reduction of soft costs for this technology. As the improvement achieved in the solar field seems to offset the investment of an additional but smaller tower and receiver, the multitower approach might lead to a certain cost reduction of STE tower plants.
关键词： field efficiency,CSP,multitower approach,STE,northern fields,Tower Plants,Solar Thermal Electricity,atmospheric transmittance
更新于2025-09-04 15:30:14