Irradiation Time Research Articles

Electric properties for thin films of microwave treated hydrophilic graphite fabricated by liquid-liquid interface

Abstract This paper reports the results of an attempt to combine microwave treated hydrophilic graphite (MwHG), a new carbon material that is both hydrophilic and electrically conductive, with a new deposition method using the interface between the aqueous and organic phases, the liquid-liquid interface deposition method (L-L method). The synthesized MwHG was characterized by X-ray diffraction (XRD) and Raman spectroscopy, and the deposited MwHG films were characterized by scanning electron microscopy (SEM) and electrical properties. It was found that the crystallinity of MwHG was changed by changing the microwave irradiation time during the synthesis of MwHG. It was also found that the high electrical conductivity was related to the microwave irradiation time or the order in which the films were deposited. Furthermore, the surface morphology of the films consisted of agglomerations of particles of different sizes with pores, and the size of the particles decreased with the number of depositions.

Degradation of Decabromodiphenyl Ether Dispersed in Poly (Acrylo-Butadiene-Styrene) Using a Rotatory Laboratory Pilot Under UV-Visible Irradiation.

The growing volume of plastics derived from electronic waste (e-waste) underscores the imperative for environmentally sustainable strategies for the management of this waste. In light of the paramount importance of this issue, a pilot demonstrator for the decontamination of polymers containing Brominated Flame Retardants (BFRs) has been developed. The objective is to investigate the potential for decontaminating BFR-containing polymers from e-waste via UV-visible irradiation using a rotatory laboratory pilot operating under primary vacuum conditions. This report focuses on binary model blends composed of 90 weight% (wt%) poly(Acrylo-Butadiene-Styrene) (ABS) pellets and 10 wt% Deca-Bromo-Diphenyl Ether (DBDE), which is one of the most toxic BFRs. The efficiency of the irradiation process was evaluated as a function of pellet diameter and irradiation time using Fourier Transform InfraRed spectroscopy (FTIR) and High-Resolution Laser Desorption/Ionization Mass Spectroscopy (HR-LDI-MS). As a consequence, ABS + DBDE achieved a decontamination efficiency of 97% when irradiated with pellets of less than 1 mm in diameter for a period of 4 h. Additionally, the thermal behavior of the irradiated samples was investigated through thermogravimetric analysis and differential scanning calorimetry. It was thus established that the application of UV-visible irradiation had no significant impact on the overall thermal properties of ABS.

Experimental Study on Optimizing Hydrogen Production from Sludge by Microwave Catalytic Pyrolysis Using Response Surface Methodology.

Catalytic pyrolysis technology is a harmless and useful solid waste treatment method. Studying the catalytic pyrolysis of sludge for hydrogen production is of practical significance. Therefore, this paper prepared a bifunctional catalyst with both microwave absorption and catalytic properties from electroplating sludge through carbonization and acid modification processes and then was characterized by XRD, BET, SEM, XPS, and FTIR. An experimental study employed a conventional-then-microwave pyrolysis method to investigate the catalytic pyrolysis process of municipal sludge. Combining central composite design (CCD) and response surface methodology (RSM) with three factors and five levels, this paper investigated the interactive effects of the conventional pyrolysis temperature, microwave irradiation time, and catalyst addition ratio on the unit hydrogen production (UHP) of sludge. A predictive model based on a second-order polynomial regression equation was developed. The results revealed that the catalyst possesses a specific surface area and pore structure and that the second-order polynomial model fits well. The conventional pyrolysis temperature, microwave irradiation time, catalyst addition ratio, and interaction between the latter two significantly affected the UHP of sludge. The optimal operation conditions of conventional pyrolysis temperature, microwave irradiation time, and catalyst addition ratio were 462.7 °C, 8.8 min, and 12.4%, respectively. Under these optimal conditions, the UHP was 13.22 mmol/g, with a relative error of only 1.12% compared to the predicted model value of 13.37 mmol/g.

Diode Laser Irradiation Effects on Physical Properties of Titanium Dioxide Nano Fillers Doped Polyvinyl Alcohol Films

Study effect of diode laser (wavelength 650 nm) irradiation for different irradiant times (0.25, 0.5, 1.00, 3.00, and 4.00 hrs) on the physical properties of titanium dioxide (TiO2) possess particle size of 15.7 nm doped polyvinyl alcohol (PVA) films were experimentally investigated. The solution casting process has been utilized to create as-prepared TiO2/PVA nanocomposite films. Ultraviolet-Visible (UV-Vis) spectroscopy investigates the samples' optical characteristics by analyzing optical absorption spectra in a wavelength range of (200 - 900 nm) at room temperature (RT) of 300 K. The PVA matrix could be used to describe the influence. All optical constants produced artificially through laser radiation, like absorption, refraction index, extinction coefficient and complex dielectric constants, have decreased with increasing radiation times. On the contrary of optical energy gap they increased with increasing radiation times, according to the study's findings. TiO2 Nanoparticles (NPs) additions significantly impacted the PVA host's optical characteristics. When FTIR-spectrum regarding the TiO2/PVA nanocomposite films was examined in various ratios of irradiation times, the peak positions or bonds did not change; instead, they became smaller or larger as the irradiation time increased.

Pea Pod–Derived Biochar–Zeolitic Imidazolate Framework Composite for the Photocatalytic Degradation of Two Organic Dyes Crystal Violet and Victoria Blue

ABSTRACTThe rapid increase of water pollution globally is a vital environmental concern that requires the immediate attention of researchers to find new innovative ways to remove unwanted environmental pollutants from our water sources. With the advances in the field of sustainable engineering, there is a high demand for the effective utilization of biomass resources for the removal of aqueous environmental contaminants. Biochar is carbon carbon‐enriched substance obtained by biomass pyrolysis; it is inexpensive and has received wide attention in the field of wastewater treatment. Herein, we describe the synthesis of pea pod (PO) biochar‐reinforced zeolitic imidazolate framework (ZIF‐8) nanocomposite (PO@ZIF‐8) through the in situ precipitation of ZIF‐8 onto the biochar surface. The crystal growth, morphology, chemical composition, and optical characteristics of fabricated PO@ZIF‐8 nanocomposite were scrutinized through PXRD, SEM, TEM, UV‐DRS, PL, and XPS analysis. The dodecahedral‐shaped PO@ZIF‐8 particles have an average size between 140 and 160 nm. The biochar‐reinforced ZIF‐8 nanocomposite showed significantly higher photocatalytic activity than the pure ZIF‐8 for the degradation of two commonly found organic dyes crystal violet (CV) and Victoria Blue (VB) in the presence of direct sunlight irradiation. The PO@ZIF‐8 nanocomposite showed the highest degradation efficiency of ~87% and ~80% within 50 min of irradiation time at a catalyst dosage of 20 mg for 30 ppm CV and VB dye solutions at pH 8. First‐order kinetics were obeyed during the photodegradation with 0.041 and 0.030 min−1 as the constant of degradation for the removal of CV and VB. The radical scavenger experiment and the photoluminescence analysis confirm the active participation of ·OH radical in the degradation of both dyes. LC–MS and TOC analysis was also performed to determine the degradation products and for evaluation of the degradation progress. Moreover, the synthesized PO@ZIF‐8 composite also exhibit good stability till the fourth cycle with high degradation efficiency thus making it a good choice of catalyst in the field of environmental decontamination.

Highly Efficient Sunlight‐Driven Photocatalytic Activity of Cu‐Doped BiOBr/g‐C3N4 Nanocomposite via Z‐Scheme Design

AbstractPharmaceutical pollutants introduce highly intricate compounds into the environment due to extensive structural and functional alterations resulting in adverse health effects on organisms. Herein, a novel nanocomposite is designed comprising Cu‐doped BiOBr nanoflakes and g‐C3N4 to form a dual absorber based on the organic‐inorganic electronic interface for photocatalytic degradation of tetracycline (TC). With incorporating Cu in BiOBr and compositing with g‐C3N4, the band gap decreased from 2.74 eV to 2.36 eV for BiOBr:Cu/g‐C3N4, and also light harvesting ability increased. The investigation into the degradation rate considered factors such as pH, TC concentration, photocatalyst dosage, and irradiation time, resulting in a TC degradation efficiency of 98 % within 60 min. In the prepared nanocomposite, photo‐generated electrons of BiOBr can recombine via Cu atoms as a mediator with holes in the valence band of g‐C3N4 due to their band structure position which leads to improved electron/hole separation and enhanced photocatalytic activity. The predominant active species involved in the degradation process were found to be superoxide radicals. Additionally, the photocatalyst exhibited excellent stability, retaining 88 % of its photocatalytic activity after four cycles.

N‐Arylphenothiazines and N,N‐Diarylphenazines as Tailored Organophotoredox Catalysts for the Reductive Activation of Alkenes

AbstractA small library of N‐arylphenothiazines, N‐arylbenzo[b]phenothiazines and N,N‐diarylphenazines has been synthesized as strongly reducing organophotocatalysts without the need for sacrificial reagents or electrochemistry. Their opto‐electronic properties and their suitability as organophotoredox catalysts for the efficient activation of olefins was investigated using the addition of methanol to α‐methylstyrene as a model reaction. The findings were supported by DFT calculations. Three photocatalysts were identified that allowed quantitative yields with 10 mol % catalyst loading and 20 h irradiation by a 365 nm LED. The catalyst loading was gradually reduced to 0.5 mol % and the irradiation time was reduced to only 20 min. These experiments revealed that N,N‐diisobutyl‐4′‐(10H‐phenothiazin‐10‐yl)‐[1,1′‐biphenyl]‐4‐amine is the most efficient photocatalyst among the N‐arylphenothiazines. This chromophore combines high electron density introduced by the diisobutylamino phenyl group with high absorptivity at 365 nm caused by the phenylene bridge to the phenothiazine core. In an attempt to shift the excitation wavelength into the visible light range for selectivity and sustainability purposes (potential use of sunlight as a light source), N‐arylbenzo[b]phenothiazines N,N‐diarylphenazines were designed that exhibit a red‐shifted and broad absorbance shoulder into the visible range, but only N,N‐diarylphenazines allow photocatalysis and the one‐electron activation of alkenes by visible light (450 nm LED).

Decolorization of Acid Red 337 dye with hydroxyl and sulfate radical based advanced oxidation processes using different iron Catalyst: An experimental and statistical Investigation

The removal efficiencies of Acid Red 337 dye were investigated by combining advanced oxidation processes based on OH and SO4− radicals. The photocatalytic oxidation processes were carried out at the natural pH (5.4) and acidic pH (3.0) values of the dye solution. In the experiments, iron (II) sulfate (Fe2+) and potassium ferrioxalate (FeOx) were used as catalysts, hydrogen peroxide (H2O2) and peroxymonosulfate (PMS) were used as oxidants to compare dye removal efficiency and to determine the optimum doses. This comparison provided the opportunity to identify suitable catalysts and oxidants for dye removal. Furthermore, time-based comparisons were conducted from 2 to 10 min using the optimum catalyst doses. It was obtained that PMS was more effective as an oxidant in the presence of both iron catalysts for colour removal. The colour removal efficiency of 98.2 % was achieved in the PMS/Fe2+/UV process with doses of 1 mM PMS and 0.1 mM Fe2+ at pH 5.4 and an irradiation time of 10 min. In experiments using light-sensitive ferrioxalate (FeOx), colour removal was achieved in the PMS/FeOx/UV process with an efficiency of 97.8 %. Additionally, an artificial neural networks (ANNs) model effectively optimized the oxidation parameters, with predicted values closely matching the experimental data. The ANNs model yielded excellent statistical performance, with a root mean square error (RMSE) of 0.0317, 0.0223 and coefficient of determination (R2) of 0.9690 and 0.9854 for UV/Fe2+/H2O2-UV/FeOx/H2O2 and UV/Fe2+/PMS-UV/FeOx/PMS oxidation systems respectively.

Green synthesis of silver nanoparticles using Lepidium sativum seed mucilage as a bioreductant/capping agent for efficient antibacterial and photocatalytic activities

Contamination of aquatic resources with organic dyes and pathogenic bacteria ranks among the most serious threats to human survival and the environment. The current work investigated L. sativum seed mucilage as a reducing and capping agent for Ag NPs. From UV–vis spectroscopy, the characteristic surface plasmon resonance peak and the band gap energy of as-fabricated NPs were 440 nm and 2.07 eV, respectively. SEM revealed irregular-shaped NPs with an average diameter of 73.85 nm and EDX disclosed Ag along with C, O, and Si from mucilage’s biomolecules. The antibacterial and antibiofilm results showed higher inhibitory effects against the Gram-positive (B. cereus) than the Gram-negative (E. coli, and E. aerogenes) bacteria. The biosynthesized NPs were impressive in degrading methylene blue (MB, 89.45 %) and methyl orange (MO, 84.78 %) under optimized conditions viz., dye solution (20 ppm), photocatalyst dose (5 mg), light intensity (UV index of 10 +), and irradiation time (120 min). The kinetic data strongly supported the pseudo-first order model with maximum adsorption capacities of 787.40 and 724.64 mg/g for MB and MO, respectively as determined through the Langmuir isotherm model. The photocatalyst exhibited sufficient stability even after six repeated cycles, highlighting its suitability for industrial and commercial applications.

Zinc determination in common beans by pXRF: An easy and versatile calibration strategy applied to biofortification studies

Zinc deficiency is observed in millions of individuals, especially in underdeveloped countries. Therefore, agronomical strategies have been implemented to mitigate this public health issue, mainly by the biofortification of staple food crops, e.g., common beans, one of the most consumed leguminous grains worldwide. Accurate Zn determination by an analytical method is one of the most relevant steps in these initiatives. This study evaluated three calibration methods for Zn determination by portable X-ray Fluorescence Spectrometry (pXRF) in pelletized common bean samples. A Ti/Al primary filter and a 10-second irradiation time were selected as optimized operating conditions. The sample with the highest Zn content was submitted to acid extraction with diluted HCl and HNO3 to obtain synthetic blanks. Increasing amounts of the original sample were mixed with the obtained blanks to prepare the calibration curves standards. An additional calibration model with plant-based CRMs was also evaluated. Zinc mass fractions calculated using the calibration model of HCl-extracted and mixed samples showed statistical agreement with the reference data as demonstrated by the Student t-test at a 95 % confidence level. The linear correlation factor (r) was greater than 0.99, with a detection limit as low as 2.23 mg kg−1. The obtained calibration model also exhibited high prediction capability, as revealed by the low RMSEP (Root Mean Square Error of Prediction), i.e., 2.16 mg kg−1. We concluded that pXRF is an attractive and cost-effective method for direct, quick, and environmentally friendly Zn determination in common beans.

The role of microwave radiation in extractive desulfurization of real diesel fuel for green environment: an experimental and computational investigation

The process of removing sulfur compounds and aromatic compounds to produce clean fuel is an important and effective contribution to the processes of mitigating and adapting to climate change. In contrast, it is necessary to find an innovative way to remove sulfur and carcinogenic aromatic compounds because clean, low-sulfur diesel is commonly used in all countries of the world at the present time. Therefore, in this work, we have studied the effect of the microwave radiation power and the irradiation time with the use of more than one type of organic solvent; methanol, acetonitrile and ethyl acetoacetate; as an extractant and solvent to feed ratio impact on the removal of sulfur and aromatic compounds of a real diesel fuel feed which has 450 ppm sulfur content and 16 wt% aromatic Content. The results showed that the best solvent used during this work was ethyl acetoacetate. According to the results, high sulfur removal (≈ 92%) was accomplished with microwave-assisted extractive desulfurization technique under the following ideal conditions: the irradiation time is 7 min, the solvent feed ratio is 3:1 and the microwave intensity is 180 W. To reveal the mechanism of microwave-assisted extractive desulfurization via different organic solvents, a theoretical study including structural examination and interaction energy analysis on the interaction between dibenzothiophene (DBT) or dimethyl dibenzothiophene (DMDBT) and the different organic solvents was also conducted.

An S-scheme TiO2/g-C3N4 nanocomposite effectively degrades phenanthrene under visible light

It is a challenge to effectively degrade phenanthrene (PHE) pollutants, which are widely present in aquatic environments, in order to reduce harm to humans and ecosystems. In this study, an S-scheme TiO2/g-C3N4 photocatalytic system is constructed using 0D TiO2 nanospheres and 2D g-C3N4 nanosheets for the removal of PHE from water under sunlight irradiation. The effects of irradiation time, quality ratio of TiO2 to g-C3N4, and cycle time on the performance of the TiO2/CN photocatalyst are investigated. The experimental results show that the ratio of TiO2 to g-C3N4 significantly affects the photocatalytic activity of the photocatalyst. Under the optimal ratio of TiO2 to g-C3N4 (50 % TiO2/CN), the apparent reaction rate constant for phenanthrene reached 0.00796 min−1, which is 11.5 times higher than that of pure TiO2 (0.00069 min−1). The tests of optical performance and photoelectrochemical properties further confirmed that the construction of the TiO2/g-C3N4 S-type photocatalyst successfully enhanced the spatial separation efficiency of photogenerated carriers and ensured a continuous supply of energy during the redox reaction process. Converting highly toxic phenanthrene into a non-toxic green degradation product provides an practical strategy for the safe treatment of PHE in aqueous environments through the use of visible-light-driven heterojunction photocatalysts. Additionally, the data collected on phenanthrene degradation in this study will provide valuable references for developing degradation methods for other PAHs, such as naphthalene, anthracene, and pyrene.

The efect of low-dose gamma radiation on the development of plants from irradiated Pisum sativum sprouts in laboratory experiments

The problem of radiation exposure to organisms is relevant for areas where nuclear industry enterprises are located. Plant biotests are widely used for biotesting of anthropogenic factors affecting the environment, including radiation. The sensitivity of growth and cytogenetic parameters of the biotest based on Pisum sativum to the action of gamma irradiation n has been shown before, but only at high doses. The purpose of this work was to evaluate the influence of low-dose gamma irradiation on the development of Pisum sativum over 6-10 days after irradiating the sprouts. In the experiments, seeds of the Radomir sowing variety from the collection of the pea breeding laboratory of Krasnoyarsk Research Institute of Agriculture - Federal Research Centre Krasnoyarsk Scientific Center SB RAS were used. Pea sprouts were irradiated with a 137Cs source for 24 and 72 hours, with the absorbed dose being 20 and 62 mGy. After irradiation, the sprouts were grown in a climatic chamber on hydroponics for 10 days (240 hours). The control consisted of non-irradiated sprouts grown under identical conditions. The experiments for the first time provided reliable data on the negative effects of gamma irradiation (20 and 62 mGy) on the development of sowing peas 6-10 days after irradiation. A negative effect of gamma irradiation on the growth of the main and lateral roots of young plants was revealed. The experiments with irradiated pea sprouts confirmed the previously known fact that plant roots are more sensitive to irradiation compared to shoots. The pattern of change in the length of the main root of peas over time during germination at a dose of 20 mGy is described by a linear equation, while for a higher dose of irradiation, 62 mGy, the data can be approximated by a logarithmic equation with saturation. The different character of root length dependence on the time of cultivation after irradiation indicates a possible trend in plant growth under various doses of irradiation and cultivation times.

Optimization of microwave-assisted pectin extraction from walnut shells and evaluation of its physicochemical and biological attributes

Walnuts, known for their high nutritional value, generate significant waste in the form of husks and shells, the disposal of which contributes to environmental pollution. The utilization of this walnut waste for the production of beneficial compounds remains underexplored. In the current study, extraction time, temperature, microwave power, and solid-to-solvent ratio were optimized using response surface methodology. This technique significantly reduced the extraction time, yielding pectin at 34.13 ± 3.83 % under optimal conditions: temperature (74 °C), microwave power (400 W), irradiation time (16 min), and solid-solvent ratio (1:25). XRD characterization revealed the crystalline nature of the extracted pectin, while FTIR confirmed the presence of major functional groups. The extracted pectin exhibited an equivalent weight of 576.99 ± 7.63 g/mol with a degree of esterification of 59.88 ± 0.28 %, making it suitable for food, pharmaceutical, and cosmetic applications. Further, the extracted pectin demonstrated significant antioxidant activity with IC50 values of 5.08 ± 0.08 mg/ml for DPPH and 2.87 ± 0.023 mg/ml for ABTS assays. It also showed antibacterial activity against both gram-positive Staphylococcus aureus MTCC 96 and gram-negative Pseudomonas aeruginosa MTCC 424, with zones of inhibition measuring 25.33 ± 0.58 mm and 28.33 ± 0.58 mm, respectively. SEM analysis revealed changes in cell morphology of S. aureus and P. aeruginosa when treated with the extracted pectin. These findings suggest that microwave-assisted extraction offers a rapid, eco-friendly, and cost-effective method for pectin extraction from walnut shells, promoting sustainable utilization of this waste resource and providing a potential pectin source with enhanced biological activity.

Ultraviolet Irradiation Surface Treatment to Enhance the Bonding Strength of Polyamide-Based Carbon Fiber-Reinforced Thermoplastic Polymers.

Adhesive bonding is a suitable joining method to satisfy the increasing industrial demand for carbon fiber-reinforced polymers without the need for a machining process. However, thermoplastic-based carbon fiber-reinforced polymers have small adhesive strength with structural thermoset adhesives. In this study, an ultraviolet irradiation surface treatment was developed to improve the adhesive bonding strength for polyamide-based carbon fiber-reinforced polymer. The type of ultraviolet wavelength, irradiation distance and irradiation time were optimized. Surface treatment with simultaneous UV irradiation of 185 nm and 254 nm wavelength generated unbound N-H stretching that was capable of chemical bonding with epoxy adhesives through a photo-scission reaction of the amide bond of polyamide matrix. Therefore, ultraviolet irradiation treatment improved the wettability and functional groups of the polyamide-based carbon fiber-reinforced polymers for adhesive bonding. As a result, the adhesive strength of the polyamide-based carbon fiber-reinforced polymers was increased by more than 230%.

Eco-friendly synthesis of CuO/Bi2O3 nanocomposite for efficient photocatalytic degradation of rhodamine B dye.

Plant-mediated synthesized materials are receiving more attention than conventional ones due to their wide availability, ease of access, simple preparation methods, environmental benign, and possess superior physicochemical properties. In this work, plant extract-mediated CuO, Bi2O3, and CuO/Bi2O3 nanocomposite samples were successfully synthesized using bamboo leaves extract as a capping agent. These materials were utilized for the photodegradation of Rhodamine B (RhB) dye, which served as a model organic dye pollutant. The physicochemical characterization techniques such as XRD, SEM-EDS, FTIR, and DRS-UV-vis spectrophotometry provide insight into the crystal structure, morphology, surface functional groups, and optical properties. These analyses confirm the effective formation of CuO, Bi2O3, and CuO/Bi2O3 materials. Surprisingly, upon calcination at 450°C for 4h, the color of the nanocomposite changed from pale green to gray greenish, providing evidence for the formation of the CuO in CuO/Bi2O3 nanocomposite. The photocatalytic optimization parameters such as pH (4), catalyst load (35mg), irradiation time (180min) and concentration of RhB (10 mg L-1) dye were investigated. By coupling CuO with Bi2O3 nanoparticles resulted in an improved photocatalytic property for the degradation of RhB dye under optimal conditions. As a result, CuO/Bi2O3 nanocomposite exhibited a significantly boosted photocatalytic degradation efficiency (95.6%) compared to pure CuO (40.2%) and Bi2O3 (80.5%) photocatalysts, with good reusability. For comparison purpose, the photocatalytic degradation of RhB dye using selected photocatalyst was evaluated under dark and sunlight systems. This eco-friendly approach holds great potential for synthesis new nanocomposite with modified properties, thereby enabling the practical application of high-efficiency photocatalysts. The plausible mechanism of the electrons and holes transfer was proposed.

Photocatalytic Degradation of Mancozeb Pesticide Residue using Nanoceria Doped Zinc Oxide Nanoparticles under Natural Solar Irradiation

Introduction: Excessive applications of agrochemicals to meet the high food demand from ever-increasing populations are becoming a major issue for both health practitioners and environmental managers. Chemicals such as ethylene bis-dithiocarbamate pesticide mancozeb (MCZ) are known to have deleterious effects on the ecosystem. AIM: This study, aimed at assessing the suitability of cerium-doped zinc oxide (Ce-ZnO) for efficient degradation of MCZ fungicide. Method: The photocatalysts were synthesized using the coprecipitation method with zinc nitrate hexahydrate, cerium nitrate hexahydrate, and sodium hydroxide. The synthesized nanocomposites were further characterized by Powder X-ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDAX). The average crystallite size of the as-synthesized particles was found to be 31.42 nm, with very sharp PXRD peaks revealing the pure crystal nature of the particles. The photocatalytic degradation activity was evaluated following a series of experiments under natural environmental conditions. The optimal conditions for the degradation of MCZ fungicide using Ce-ZnO were found to be 10 ppm initial concentration of MCZ, 20 mg dose of the Ce- ZnO photocatalyst, 180 minutes irradiation time, and 10-11 atmospheric UV index. Result: At the optimum conditions, the degradation efficiency was found to be about 90% after 180 minutes. The reported photocatalytic degradation of MCZ using Ce-ZnO fits a pseudo-firstorder kinetic model with an R2 value of 0. 9677. Similarly, the reusability of the as-synthesized photocatalyst was evaluated and found to be active for five rounds with little change in the activity. Conclusion: Thus, the degradation method in the current study can be suitable for the degradation and removal of MCZ in agricultural runoff in the field.

Multi-stage and multi-colour liquid crystal reflections using a chiral triptycene photoswitchable dopant.

The photomodulation of the helical pitch of cholesteric liquid crystals results in dynamic and coloured canvases that can potentially be used in applications ranging from energy-efficient displays to colour filters, anti-counterfeiting tags and liquid crystal (LC) lasers. Here we report on the analysis of a series of photoswitchable chiral dopants that combine the large geometrical change and bistability of hydrazone switches with the efficient helical pitch induction of the chiral motif, triptycene. We elucidate the effects that conformational flexibility, dispersion forces and π-π interactions have on the chirality transfer ability of the dopant. We then use the irradiation time with visible light (442 nm) combined with a simple digital light processing microscope projection set-up to draw numerous stable multi-coloured images on an LC canvas, showcasing the fine control this dopant yields over the LC assembly.

Benchmark of estimated solar irradiance data at high latitude locations

Estimated solar irradiances from CAMS, PVGIS SARAH-2, Solargis, Meteonorm, PVGIS ERA5, and NASA POWER are benchmarked against measurements conducted at 34 ground stations in Norway at latitudes between 58 and 76°N. We find that the data products that mainly rely on high-resolution, geostationary satellite images, i.e., CAMS, PVGIS SARAH-2, and Solargis, have higher accuracy with lower relative Mean Absolute Error (rMAE) and relative Mean Bias Error. By dividing the stations in distinct categories, such as above 65°N, snow-affected and horizon-shaded, challenges with irradiance estimation that are common in Norway and at high latitudes in general are highlighted and discussed. The accuracy of the data products is dependent on latitude, and by excluding stations above 65°N, the median rMAE of the different data products improves 3.2 – 9.4 %abs compared to the median rMAE when including all stations, depending on data product. Similarly, by excluding snow-affected stations, the median rMAE improves 1.9 – 8.1 %abs, depending on data product. The improvement in rMAE by excluding snow-affected stations is partially related to the difficulty of separating snow on the ground from cloud cover in satellite images. This difficulty is illustrated by concrete examples of irradiance time series from clear sky days when the ground is covered in snow. Although the performance of the data products is dependent on the categorization of stations, i.e., latitude, snow conditions, and local topography, the relative performance between the products is maintained regardless of sub-division.

Accurate measurements of delayed neutron data for reactor applications: methodology and application to 235U(nth,f)

Large inconsistencies still exist in nuclear data libraries regarding the kinetic parameters of delayed neutron (DN) precursors. As an example, there is a 17% gap between ENDF-B/VIII.0 and JEFF-3.3 on the average lifetime T1/2 of DN precursors from thermal fission of 235U. This parameter is of major importance for reactivity predictions of nuclear reactors in nominal or accidental configurations. In this context, CEA is actively participating to the ALDEN project (Average number and Lifetime of DElayed Neutrons) which aims at providing the nuclear data community with new data sets of DN from thermal and fast neutron induced fission of various actinides. A dedicated experimental setup was designed and optimized for that purpose and is presented in this paper. It consists of a “long counter” detector containing 16 proportional counters filled with 3He, embedded in a high density polyethylene matrix. The detector surrounds a fissile target prepared in the form of a miniature fission chamber, containing a few hundreds of micro-grams of fissile material. This set-up is connected to fast and efficient neutron shutters that can produce step-irradiations of variable durations. The equations driving the DN counting following step-irradiations of the fissile target are established and discussed in the perspective of DN yield or group parameter measurement. A comprehensive analysis of the different steps of data reduction is detailed: dead time characterization, Region of Interest (ROI) determination, absolute and relative efficiency calibration, fission rate estimation, irradiation time and background determination, DN decay curve production and physical parameter fitting. Following a prototype experiment performed in 2018 at the PF1b cold neutron beam line of Institute Laue Langevin (ILL, Grenoble, France), we discuss here the analysis of two campaigns occurring in 2019 and 2021 in which significant improvements were achieved in terms of background minimization, counting statistics and fission rate determination. The achievements of this work are the measurement of the delayed neutron emission per fission for the thermal neutron induced fission of 235U, estimated at (1.625 ± 0.010) % and the group parameters leading to an estimated lifetime of T1/2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${T}_{1/2}$$\\end{document} = (8.87 ± 0.10) s. Those results are consistent with the values recommended by the IAEA/CRP work and they come with reduced uncertainties compared with previously published results.