This work shows the results of the biosynthesis of silver nanoparticles using the microalga Chlorella sp, using growth media with different concentrations of glycerol, between 5%–20%, and different light and temperature conditions. The synthesis of nanoparticles was studied using supernatants and pellets from autotrophic, heterotrophic and mixotrophic cultures of the microalga. The presence of nanoparticles was verified by ultraviolet-visible spectroscopy and the samples showing the highest concentration of nanoparticles were characterized by scanning electron microscopy. The mixotrophic growth conditions favored the excretion of exopolymers that enhanced the reduction of silver and thus the formation of nanoparticles. The nanoparticles obtained presented predominantly ellipsoidal shape with dimensions of 108 nm × 156 nm and 87 nm × 123 nm for the reductions carried out with the supernatants of the mixotrophic cultures with 5% and 10% glycerol, respectively.
An image adaptive noise reduction enhancement algorithm based on NSCT is proposed to perform image restoration preprocessing on the defocused image obtained under the microscope. Defocused images acquired under micro-nano scale optical microscopy, usually with inconspicuous details, edges and contours, affect the accuracy of subsequent observation tasks. Due to its multi-scale and multi-directionality, the NSCT transform has superior transform functions and can obtain more textures and edges of images. Combined with the characteristics of micro-nanoscale optical defocus images, the NSCT inverse transform is performed on all sub-bands to reconstruct the image. Finally, the experimental results of the standard 500 nm scale grid, conductive probe and triangular probe show that the proposed algorithm has a better image enhancement effect and significantly improves the quality of out-of-focus images.
In this study, optical and microwave satellite observations are integrated to estimate soil moisture at the same spatial resolution as the optical sensors (5km here) and applied for drought analysis in the continental United States. A new refined model is proposed to include auxiliary data like soil texture, topography, surface types, accumulated precipitation, in addition to Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) used in the traditional universal triangle method. It is found the new proposed soil moisture model using accumulated precipitation demonstrated close agreements with the U.S. Drought Monitor (USDM) spatial patterns. Currently, the USDM is providing a weekly map. Recently, “flash” drought concept appears. To obtain drought map on daily basis, LST is derived from microwave observations and downscaled to the same resolution as the thermal infrared LST product and used to fill the gaps due to clouds in optical LST data. With the integrated daily LST available under nearly all weather conditions, daily soil moisture can be estimated at relatively higher spatial resolution than those traditionally derived from passive microwave sensors, thus drought maps based on soil moisture anomalies can be obtained on daily basis and made the flash drought analysis and monitoring become possible.
Providing and using energy efficiently is hampered by concerns about the environment and the unpredictability of fossil fuel prices and quantities. To address these issues, energy planning is a crucial tool. The aim of the study was to prioritize renewable energy options for use in Mae Sariang’s microgrid using an analytical hierarchy process (AHP) to produce electricity. A prioritization exercise involved the use of questionnaire surveys to involve five expert groups with varying backgrounds in Thailand’s renewable energy sector. We looked at five primary criteria. The following four combinations were suggested: (1) Grid + Battery Energy Storage System (BESS); (2) Grid + BESS + Solar Photovoltaic (PV); (3) Grid + Diesel Generator (DG) + PV; and (4) Grid + DG + Hydro + PV. To meet demand for electricity, each option has the capacity to produce at least 6 MW of power. The findings indicated that production (24.7%) is the most significant criterion, closely followed by economics (24.2%), technology (18.5%), social and environmental (18.1%), and structure (14.5%). Option II is strongly advised in terms of economic and structural criteria, while option I has a considerable advantage in terms of production criteria and the impact on society and the environment. The preferences of options I, IV, and III were ranked, with option II being the most preferred choice out of the four.
Disease epidemics may spread quickly and easily throughout nations and continents in our current global environment, having a devastating effect on public health and the world economy. There are over 513 million people worldwide who have been infected, and more than 6.2 million have died due to SARS-CoV-2. There are treatments but no cures for most viruses. Nevertheless, the spread of viruses can be limited by introducing antiviral coatings on public area surfaces and personal protective equipment (e.g., face masks). This work aims to fabricate a polymer-based coating with acrylic resin as a binder that possesses great antiviral activity against the Feline coronavirus (FCov). The chosen polymer, polyethylene glycol (PEG), is used as an antiviral agent because it contains “green” chemistry benefits such as non-toxicity, being inexpensive, readily recyclable, safe, natural, non-flammable, biocompatible, and biodegradable. The PEG/acrylic coating systems of different weight percentages were coated on the glass substrates by the spray-coating method and cured at room temperature for 24 hours. The developed PEG/acrylic coating system that contains 20 wt% of PEG exhibits the highest anti-viral activities (99.9% against FCov) compared to the other weight percentages. From this study, it has been observed that the hydrophilicity of the coating plays an important role in its antiviral activity. The developed coating has a hydrophilic property, in which the contact angle was measured at 83.28 ± 0.5°. The FTIR reveals that there are no existing toxic components or new components contained in the coating samples.
Branched micro/nano Se was prepared by the redaction of L-Cys•HCl and H2SeO3 in hydrothermal method, as β-CD was used as soft template. The structures of products were characterized by SEM, TEM and XRD. Some important factors influencing the morphology of products were studied and discussed, including the amounts of soft template, the reaction temperature and the reaction time. The results showed that external causes had a potent effect on the morphology of micro/nano Se. The uniform branched micro/nano Se prepared under the optimal reaction condition was rhombohedral trigonal selenium t-Se0, but its crystallinity degree was low.
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