Irradiation Cycles Research Articles

Thermal coagulum formation and hemostasis during repeated multipulse Nd:YAG laser treatment of cutaneous vascular lesions: animal experiment study.

Laser therapy has been widely used to treat port-wine stain (PWS) and other cutaneous vascular lesions via selective photothermolysis. High incident laser fluence is always prohibited in clinic to prevent the thermal damage in normal skin tissue, leading to insufficient energy deposition on the target blood vessel and incomplete clearance of PWS lesion. In this study, repeated multipulse laser (RMPL) irradiation was proposed to induce acute thermal damage to target blood vessels with low incident fluence (40J/cm2 for 1064-nm Nd:YAG laser). The feasibility of the method was investigated using animal models. Repeated multipulse irradiation cycles with 10-min intervals were performed in RMPL. A hamster dorsal skin chamber model with a visualization system was constructed to investigate the instant generation of thermal coagulum and relevant hemostasis by thrombus formation during and after irradiation under 1064nm Nd:YAGsinglemultipulse laser (SMPL) and RMPLirradiation. The diameter of the target blood vessel and the size of thermal coagula were measured before and after laser irradiation. The reflectance spectra of the dorsal skin were measured by a reflectance spectrometer during RMPL. Stasis thermal coagula that clogged the vessel lumen were generated during SMPL irradiation with low incident fluence. However, there was no acute thermal damage of blood vessels. Reflectance spectra measurement showed that the generation of thermal coagula and subsequent thrombus formation increases blood absorption by more than 10% within the first 10min after laser irradiation. Acute vessel thermal damage could be induced in the target blood vessel by RMPL with low incident fluence of 40J/cm2. Compared with our previous SMPL study, nearly 30% reduction in incident laser fluence was achieved by RMPL. Low fluence RMPL may be a promising approach to improve the therapeutic outcome for patients with cutaneous vascular lesions by improving energy deposition on the target blood vessel.

The use of in vivo dosimetry within the
 combined treatment of uterine body
 cancer

Relevance: Radiotherapy is the standard post-surgery
 treatment in patients with uterine cancer. However, radiotherapy affects 90.0–100.0% of the volume of risk organs. Information on the actual dose delivered to critical structures is needed
 to ensure the quality of radiotherapy.
 The purpose of this study was to determine the impact
 of the type of ionizing radiation on the dose load on the rectal
 mucosa using in vivo dosimetry.
 Results: At the first and tenth sessions of treatment using a
 cobalt apparatus, the in vivo dosimetry showed that the minimum value of the dose received during the tenth cycle was
 higher by 0.1 Gy. That is, the deviations from the planned dose
 were less at the same maximum values. Both the average value
 and the median during the tenth cycle were also moderately
 higher. The relative difference between the dose planned and
 received during the tenth cycle was higher than during the first
 cycle by an average of 1.12575%, with a median of 0.82214.
 When conducting radiotherapy using a linear accelerator, the
 average and median values were higher in the second measurement despite almost identical minimum and maximum
 values. The relative difference between the planned and received doses during the tenth cycle was higher than during
 the first cycle by an average of 0.55619%, with a median of
 0.42948.
 Conclusion: The conducted study showed an intro- and
 interindividual variability of in vivo dosimetry results during
 radiotherapy of genital cancer patients. In vivo dosimetric
 control showed that the relative difference between the doses
 calculated and received by the rectal mucosa upon reaching of
 20.0 Gy dose in comparison to the first irradiation cycle were
 twice higher on the ROCUS-AM cobalt apparatus vs. the Clinac
 600 C linear accelerator.
 The data obtained during the investigation indicates the
 need to develop innovative approaches to topometric preparation of genital cancer patients and to continue their dosimetric monitoring to establish the causes of discrepancies in the
 results.

The use of in vivo dosimetry within the combined
 treatment of uterine corpus cancer

Relevance: Radiotherapy is the standard post-surgery treatment in patients with uterine corpus cancer. However, radiotherapy affects 90.0–100.0% of the volume of risk organs. Information on the actual dose delivered to critical structures is
 needed to ensure the quality of radiotherapy.
 The purpose of this study was to determine the impact of the type of ionizing radiation on the dose load on the rectal
 mucosa using in vivo dosimetry.
 Results: At the first and tenth sessions of treatment using a cobalt apparatus, the in vivo dosimetry showed that the minimum value of the dose received during the tenth cycle was higher by 0.1 Gy. That is, the deviations from the planned dose were
 less at the same maximum values. Both the average value and the median during the tenth cycle were also moderately higher.
 The relative difference between the dose planned and received during the tenth cycle was higher than during the first cycle by
 an average of 1.12575%, with a median of 0.82214. When conducting radiotherapy using a linear accelerator, the average and
 median values were higher in the second measurement despite almost identical minimum and maximum values. The relative
 difference between the planned and received doses during the tenth cycle was higher than during the first cycle by an average
 of 0.55619%, with a median of 0.42948.
 Conclusion: The conducted study showed an intro- and interindividual variability of in vivo dosimetry results during radiotherapy of genital cancer patients. In vivo dosimetric control showed that the relative difference between the doses calculated
 and received by the rectal mucosa upon reaching of 20.0 Gy dose in comparison to the first irradiation cycle was twice higher
 on the ROCUS-AM cobalt apparatus vs. the Clinac 600 C linear accelerator.
 The data obtained during the investigation indicates the need to develop innovative approaches to topometric preparation
 of genital cancer patients and to continue their dosimetric monitoring to establish the causes of discrepancies in the results.

Diatom evidence for mid-Holocene peatland water-table variations and their possible link to solar forcing

Peatlands located at the northern edge of the East Asian monsoon (EAM) are well placed to provide a terrestrial record of past climate and hydrological changes for this globally sensitive region. Here we present a middle to late Holocene, diatom-derived water-table records from a peatland in the Greater Hinggan Mountains, northeastern China. An age-depth model was achieved through AMS14C dating and Bayesian piece-wise linear accumulation modelling. The diatom-based water-table reconstructions show that the peatland water-table rose from 5100 to 3500 cal. yr BP, but fell approximately 3500 cal. yr BP. From about 2800 to 1500 cal. yr BP, the peatland water-table stabilized. After about 1500 cal. yr BP, several rapid hydrological shifts, which correspond with global climate anomalies such as ice-rafted debris (IRD) events, were registered in the reconstructed water-tables. Compared with other paleoclimate records in East Asia, the general trend of peatland water-table fluctuations follows the variations in the East Asian summer monsoon (EASM) intensity. Spectrum analysis of the water-table profile yielded a statistically significant periodicity of 470-year that may be related to the “~500-year” inherent solar irradiation cycles. In addition, positive correlation between the peatland water-table levels and cosmic-isotope-reconstructed sunspot numbers underscores the role of the sun in regulating hydrological processes in the EASM margin area. The data suggest that the regional climate and hydrological variations at the EASM margin were first triggered by changes in solar output, but may have been amplified by interactions with oceanic and atmospheric circulations.

Microstructural evolution and shear performance of AuSn20 solder joint under gamma-ray irradiation and thermal cycling

Owing to the excellent stability and mechanical strength, AuSn20 solder is of particular importance to the die attachment in aerospace power modules. An elevated requirement was put forward to improve the performance of solder joints for next-generation aerospace electronics. To this context, the microstructural evolution and mechanical performance of AuSn20 solder joints under independent γ-ray irradiation and thermal cycling were investigated in this work. The experimental results reveals that the shear forces of AuSn20 micro-joints were reduced by 17.5% and 25.3% after 1000 h of γ-ray irradiation and 200 thermal cycles, respectively, which are caused by the increase of interfacial IMC (intermetallic compound) layers and voids. Generally, the experimental data presented here are highly prospective because it provides new insights for the solder joint reliability in space environment, which could advance the research progress of aerospace devices without RHBD (radiation hardening by design) and ATCS (active thermal control system).

Hazai képződményekből szeparált kvarcok jellemzői az OSL kormeghatározás szempontjából

Az OSL (Optically Stimulated Luminescence) kormeghatározás alkalmazása a Magyar Állami Földtani Intézetben 2004-ben kezdődött, majd a jogutód Magyar Földtani és Geofizikai Intézetben folytatódott, és a Magyar Bányászati és Földtani Szolgálatban jelenleg is folyik. A felső-pleisztocén és holocén üledékek OSL kormeghatározása során tett megfigyeléseink szerint a kvarcok lumineszcens tulajdonságai és OSL kormeghatározásra való alkalmassága helyi eltéréseket mutat. Ezeknek az eltéréseknek az okait kerestük. Vizsgáltuk a kvarc eltérő forráskőzeteinek hatását olyan kvarcgazdag magmás, metamorf és idősebb üledékes képződményekből nyert kvarcszeparátumokon, amelyek hazánkban jelenleg a felszínen is előfordulnak, és anyaguk a negyedidőszaki üledékbe is bekerülhetett. Az OSL mérések mellett a kvarcszemcsék kristályrács hibáit okozó szennyeződések kimutatására LA-ICP-MS, mikro-FTIR és IR spektrometriai méréseket alkalmaztunk. A kvarcszeparátumok pontosabb jellemzéséhez fénymikroszkópos vizsgálatot, valamint termoanalitikai és röntgen-pordiffrakciós elemzéseket végeztünk. A kvarcokat befoglaló képződmények radioaktív elemtartalmát gamma-spektrometriai mérések segítségével határoztuk meg.
 OSL mérési eredményeink alapján az üledékes képződmények és egyes vulkáni tufák kvarcszeparátumai fényesebb, nagyobb intenzitású lumineszcenciát adtak, mint a vizsgált metamorf és mélységi magmás kőzetek. Közvetlenül, az első mállási és szállítási ciklus után az üledékekbe kerülve csupán néhány üledékes képződmény kvarcszemcséi lennének alkalmasak a kormeghatározásra.
 A kvarcok OSL tulajdonságait meghatározó kristályrács hibáit az LA-ICP-MS vizsgálat szerint Li, Na, Al, P, K, Ti és Ba beépülése okozhatja, és a mikro-FTIR mérésekkel kimutatott, a Si4+ iont helyettesítő Al3+ + H+, azaz AlOH szerkezeti hidroxil, valamint molekuláris víz. A nagyobb intenzitású OSL-t adó kvarcszeparátumok befoglaló képződményei kisebb K- és Th-tartalommal rendelkeznek, mint a gyengébb OSL-t kibocsátóké.
 A negyedidőszaki üledékek kvarcainak lumineszcens tulajdonságaiban és OSL kormeghatározásra való alkalmasságában mutatkozó helyi eltérések oka az eltérő forráskőzeteik, valamint különböző hő- és üledékes történetük lehet. A mélységi magmás és metamorf kőzetek elsődleges lepusztulásából származó kvarcok kedvezőtlen OSL tulajdonságát az eredményezheti, hogy bár magas hőmérsékleten képződve sok kristályrács hiba alakult ki bennük, de azok nagy részét lassú kihűlésük során elvesztették. Az üledékes képződmények kvarcszemcséinek kedvezőbb OSL tulajdonságai elsősorban a szállításuk és áthalmozódásuk során az ismétlődő radioaktív besugárzási, azaz OSL felépülési, és napfényen az OSL lenullázódási ciklusoknak köszönhető, melyek növelik a kvarc lumineszcens érzékenységét.

Pineoblastoma in children less than six years of age: The Head Start I, II, and III experience.

We report the outcomes of patients with pineoblastoma and trilateral retinoblastoma syndrome enrolled on the Head Start (HS) I-III trials. Twenty-three children were enrolled prospectively between 1991 and 2009. Treatment included maximal surgical resection followed by five cycles of intensive chemotherapy and consolidation with marrow-ablative chemotherapy and autologous hematopoietic cell rescue (HDCx/AuHCR). Irradiation following consolidation was reserved for children over six years of age or those with residual tumor at the end of induction. Median age was 3.12 years (range, 0.44-5.72). Three patients withdrew from the study treatment and two patients experienced chemotherapy-related death. Eight patients experienced progressive disease (PD) during induction chemotherapy and did not proceed to HDCx/AuHCR. Ten patients received HDCx/AuHCR; eight experienced PD post-consolidation. Seven patients received craniospinal irradiation (CSI) with a median dose of 20.7Gy (range, 18-36Gy) with boost(s) (median dose 27Gy; range, 18-36Gy); three received CSI as adjuvant therapy (two post-HDCx/AuHCR) and four upon progression/recurrence. The five-year progression-free survival (PFS) and overall survival (OS) were 9.7% (95% confidence intervals [CI]: 2.6%-36.0%) and 13% (95% CI: 4.5%-37.5%), respectively. Only three patients survived beyond five years. Favorable OS prognostic factors were CSI (hazard ratio [HR]=0.30 [0.11-0.86], P=0.025) and HDCx/AuHCR (HR=0.40 [0.16-0.99], P=0.047). Within the HS I-III trials, CSI and HDCx/AuHCR were statistically associated with improved survival. The high PD rate during later induction cycles and following consolidation chemotherapy warrants consideration of fewer induction cycles prior to consolidation and the potential intensification of consolidation with multiple cycles of marrow-ablative chemotherapy and irradiation.

3D-VAR Data Assimilation of SEVIRI Radiances for the Prediction of Solar Irradiance in Italy Using WRF Solar Mesoscale Model—Preliminary Results

Solar power generation is highly fluctuating due to its dependence on atmospheric conditions. The integration of this variable resource into the energy supply system requires reliable predictions of the expected power production as a basis for management and operation strategies. This is one of the goals of the Solar Cloud project, funded by the Italian Ministry of Economic Development (MISE)—to provide detailed forecasts of solar irradiance variables to operators and organizations operating in the solar energy industry. The Institute of Methodologies for Environmental Analysis of the National Research Council (IMAA-CNR), participating to the project, implemented an operational chain that provides forecasts of all the solar irradiance variables at high temporal and horizontal resolution using the numerical weather prediction Advanced Research Weather Research and Forecasting (WRF-ARW) Solar version 3.8.1 released by the National Center for Atmospheric Research (NCAR) in August 2016. With the aim of improving the forecast of solar irradiance, the three-dimensional (3D-Var) data assimilation was tested to assimilate radiances from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) aboard the Meteosat Second Generation (MSG) geostationary satellite into WRF Solar. To quantify the impact, the model output is compared against observational data. Hourly Global Horizontal Irradiance (GHI) is compared with ground-based observations from Regional Agency for the Protection of the Environment (ARPA) and with MSG Shortwave Solar Irradiance estimations, while WRF Solar cloud coverage is compared with Cloud Mask by MSG. A preliminary test has been performed in clear sky conditions to assess the capability of the model to reproduce the diurnal cycle of the solar irradiance. The statistical scores for clear sky conditions show a positive performance of the model with values comparable to the instrument uncertainty and a correlation of 0.995. For cloudy sky, the solar irradiance and the cloud cover are better simulated when the SEVIRI radiances are assimilated, especially in the short range of the simulation. For the cloud cover, the Mean Bias Error one hour after the assimilation time is reduced from 41.62 to 20.29 W/m2 when the assimilation is activated. Although only two case studies are considered here, the results indicate that the assimilation of SEVIRI radiance improves the performance of WRF Solar especially in the first 3 hour forecast.

The WWR-K Reactor Experimental Base for Studies of the Tritium Release from Materials Under Irradiation

The WWR-K is 6-MW(thermal) light-water, tank-type reactor with thermal neutron spectrum. It is the exclusive multipurpose research reactor in the Republic of Kazakhstan. The WWR-K is owned by the Institute of Nuclear Physics of the Ministry of Energy of the Republic of Kazakhstan. The coolant is desalted water. The moderator and the reflector are desalted water and beryllium. The reactor operates on uranium dioxide that is enriched to 19.7% by 235U. The reactor is equipped with irradiation channels with the following characteristics: the thermal neutron flux density in the core center comprises 2 · 1014 cm−2s−1, whereas the fast neutron flux density (En > 0.1 MeV) comprises ~8 · 1013 cm−2s−1; in the core periphery, fluxes of the thermal and fast neutrons comprise, respectively, ~8 · 1013 and ~6 · 1012 cm−2s−1. The regular irradiation cycle length is 21 days. The annual number of cycles is ten.Since WWR-K reactor startup, the studies of various prospective reactor materials and fuels have been carried out in its core. Since 2000, activities on in-reactor tests of fusion reactor materials have been performed at the WWR-K reactor, such as experiments on tritium release out of lithium ceramics. Tests forced development and fabrication of an installation for in-reactor studies of tritium release from various candidate materials of fusion reactor blankets in the inert gas environment of an ampoule with specimens under study. Also, a technique has been developed for assessment of the time of tritium retention in materials under irradiation.In 2018, the WWR-K reactor facility was upgraded for studies of fusion reactor materials under irradiation, which makes it possible to carry out experiments on irradiation of specimens at vacuum conditions.This work presents the experimental facility description and block circuit along with its general technical capacities as applied to the expected studies of tritium release of fusion reactor materials at the WWR-K reactor. The developed irradiation ampoule device is presented schematically as well. Also, the obtained results of the neutron-physical, thermophysical, and vacuum calculations for the in-reactor experiment on irradiation of fusion reactor blanket materials are given.

Use of Neutron Absorbers to Influence the Neutron Transmutation Doping Process in Silicon

Neutron transmutation doping is used to create high-quality silicon with a specific target resistivity. By implementing neutron absorbers, it is possible to obtain a broader range of postirradiation resistivities. To develop this method, the influence of neutron absorbers on the reactor spectrum in Belgian Reactor 1 was numerically simulated and experimentally verified. A comparison between the modeled reactor spectrum and the spectrum obtained through activation foils showed good agreement. These data were used to calculate the resistivity of silicon under cadmium and hafnium foils with different thicknesses after neutron irradiation. Experimental four-point probe measurements confirmed the calculated resistivities. Hence, the research shows that tailoring the reactor spectrum using neutron absorbers allows for a large range of final resistivities or doping concentrations in silicon during a single irradiation cycle.

Depletion uncertainty analysis to the MYRRHA fuel assembly model

In this work, the objective is to perform an uncertainty analysis on a MYRRHA -Rev.1.6 irradiation cycle study, being applied to a depletion scenario of a single fresh fuel assembly while assuming reflective boundary conditions. Such analysis is statistically based on the application of Wilk’s method of building tolerance limits after 100 depletion calculations were performed with the SERPENT2 code. Due to the computational burden of such type of simulations, this propagation of nuclear data covariances study (allowed by the fast computational performance of SERPENT2) was done at constant power, constant flux and, in a final exercise, at constant power with the addition of fission yield uncertainties (all of these cases employed ENDF/B-VII.1 data). It was observed that while depleting at constant power, the statistical variation of key fission products such as148Nd is almost not present because of the normalization factor applied to the flux. In contrast, the irradiation at constant flux reveals dependence on burnup. Finally, the added fission yield uncertainties make clear the fact that they directly impact the degree of final uncertainty computed for fission products exemplified by148Nd and135Xe important for burnup estimation and reactor operation, respectively.

Enhanced photocatalytic hydrogen evolution on TiO2 employing vanadium carbide as an efficient and stable cocatalyst

In an attempt to construct efficient and robust photocatalysts/systems for solar H2 evolution from water splitting, the development of highly active and stable H2 evolution cocatalysts is crucial yet remains a great challenge. Herein, we present that vanadium carbide (VC) can serve as an efficient cocatalyst when integrated with TiO2 for photocatalytic H2 evolution. With 15 wt% VC, the obtained TiO2/VC (15 wt%) composite photocatalyst (denoted as TV15) shows the highest photocatalytic H2 evolution rate of 521.4 μmol h−1 g−1, while the pristine TiO2 hardly shows H2 evolution activity. The apparent quantum efficiency (AQE) of H2 evolution reaches up to 2.3% under light irradiation of 365 nm. Notably, the TV15 exhibits excellent photocatalytic stability for H2 evolution over four cycles of continuous light irradiation of 20 h. The enhanced activity of TV15 can be attributed to the cocatalyst effects of VC, which can not only effectively capture the photogenerated electrons of TiO2 to greatly enhance the charge separation efficiency but also significantly reduce the overpotential of H2 evolution reaction, thus enhancing the photocatalytic activity of TiO2/VC towards H2 evolution. This work provides a new insight to rationally design and develop efficient photocatalysts using active and stable transition metal carbides as cocatalysts.

Reversibly photoswitchable gratings prepared from azobenzene-modified tethered poly(methacrylic acid) brush as colored actuator

Line arrays of poly(methacrylic acid) brush gratings (PBGs) were prepared to hybridize azobenzene (Azo) cationic surfactants. The change in the free volume of the Azo unit between the cis-state and its trans counterpart under 365-nm irradiation resulted in geometrical-parameter variations of the PBGs. The effective refractive index (neff) of the PBGs changed from 1.202 to 1.245 under 365-nm irradiation. To observe the color change under 365-nm irradiation, the correlation between the reflection wavelength and the reflection angle at a diffraction order ranging from 1 to 5 was established to obtain the optimal observation angle. The PBG exhibited yellow light initially, which was observed at 60°–70° by the naked eye. This is consistent with our prediction. The yellow changed to red under irradiation at 365 nm and returned to yellow under irradiation at 460 nm. The photomechanical (contraction and expansion) color of the dry polymer brush was reversible with repeated irradiation cycles, indicating potential for applications in photomanipulable sensors or actuators.

Transcriptomic responses of harmful dinoflagellate Prorocentrum donghaiense to nitrogen and light

Prorocentrum donghaiense is a notoriously harmful bloom species in the coastal waters of China. The molecular processes by which P. donghaiense assimilates nitrogen (N) are poorly understood. Expression of 12 genes involved in N transport and assimilation in P. donghaiense was studied under different conditions of N availability, irradiance and diel cycle. We demonstrated that expression of 5 genes was regulated by N limitation and 7 genes regulated by different N sources or irradiances. The diel cycle had little effect on the regulation of the studied genes. The responses of the genes involved in the ornithine-urea cycle (OUC) were different from those found in model diatoms. Constitutive expression of genes related to N transport and assimilation may assist P. donghaiense efficient utilization of different N sources in varying marine environments. The OUC of P. donghaiense may play a minor role in the distribution and repackaging of carbon and N.

Enhanced Photo-Catalytic Performance of Activated Carbon Fibers for Water Treatment

The synthesis, characterization, and performance of composite photocatalytic adsorbents are investigated in this work using the dip-coating and the electrophoretic coating methods for the deposition of titanium dioxide (TiO2) on porous activated carbon fiber (ACF) substrates. The adsorption and photocatalytic efficiency of the synthesized catalytic adsorbents were compared using phenol as the model pollutant. Both immobilization techniques resulted in composite ACF/TiO2 adsorbents characterized by large surface area (844.67 ± 45.58 m2 g−1), uniform distribution of TiO2 nanoparticles on the activated carbon fibers, and high phenol adsorption. The method and the treatment time affected the phenol adsorption, while the highest sorption was determined in the case of the ACF/TiO2 sample prepared by the electrophoretic coating method (at 20 V) for an electrolysis time of 120 s (7.93 mgphenol g−1ACF/TiO2). The UV-A irradiation of most ACF/TiO2 samples led to a faster removal of phenol from water as a result of the combined sorption and heterogeneous photocatalysis. The stability and the effective regeneration of the most promising composite photocatalytic adsorbent was proved by multiple filtration and UV-A irradiation cycles.

Design of carbon loaded porous TiO2 foams by the hydrothermal-assisted annealing carbonization of fruit residue for solar-driven water evaporation

Solar-dirven water evaporation is an effective way to utilize solar energy for the fresh water production. In this paper, we constructed a hybrid photothermal conversion material including porous TiO2 foams as the water molecule transfer layer and carbon as the photothermal sensitizer. The amorphous TiO2 porous layer was prepared by the anodization of Ti foam, and then carbon materials were deposited on the surface of TiO2 layers by the hydrothermal-assisted annealing carbonization of fruit (cherry, grape, orange and apple) residue. The investigation indicated that the TiO2 substrate prepared with anodization voltage of 30 V showed the excellent microstructure and photothermal conversion efficiency, and the carbon produced from grape residue had the high evaporation rate of 1.42 kg m−2 h−1 and photothermal conversion efficiency of 59.43% under 1.5 sun irradiation (150 kW/m2). The influence of irradiation power intensity on the water evaporation was also explored, and the photothermal membrane also showed high evaporation efficiency of seawater, and the evaporation rate and photothermal conversion efficiency nearly maintained the stable value, showing superstability after 12 irradiation cycles. Based on our experimental data, the design strategy of hybrid photothermal membranes would provide effective guidance for photothermal materials in applications of seawater desalination and wastewater treatment.

Waterborne bio-based epoxy coatings for the corrosion protection of metallic substrates

Corrosion of engineering metals and alloys poses a threat to the safety and reliability of engineering structures. In this work, an environmentally-friendly hydrophobic coating was developed based on a bio-based epoxy with addition of nanoparticles, a silane coupling agent (3-glycidyloxypropyl) trimethoxysilane (GLYMO), and a hydrophobic curing agent. This coating was applied onto Fe substrates via spin-coating. The water contact angle of ˜153.0° and sliding angle of ˜14.3° were obtained for an optimal coating with 25.0 wt.% nanoparticles loading. The prepared coating exhibited high hydrophobic performance when immersed in water and common solvents including ethanol and acetone for 48 h. Besides, after exposure to continuous cycles of UV irradiation and water condensation for 24 h, this optimal coating was able to retain a high hydrophobicity at contact angle of ˜142.7°, indicating its good weathering resistance. Furthermore, the electrochemical measurements demonstrated that the optimized coating displayed a 2-orders-of-magnitude reduction in its corrosion current density and a positive shift of 0.344 V in its corrosion potential. The corresponding inhibition efficiency was 93.75%. The adsorption energy and diffusion coefficient were calculated using molecules dynamic simulation to further understand the corrosion inhibition behavior at the molecular scale. This green and bio-based water-repellent epoxy coating holds great potential towards corrosion inhibition for other metallic structures in harsh working environment.

Integrating noble-metal-free metallic vanadium carbide cocatalyst with CdS for efficient visible-light-driven photocatalytic H2 evolution

Developing highly active and stable cocatalysts at lower costs is greatly crucial for high-performance semiconductor-based photocatalytic H2 evolution from water splitting. Herein, we report that noble-metal-free metallic vanadium carbide (VC) can function as a superior cocatalyst when integrated with CdS for efficient photocatalytic H2 evolution under visible light irradiation (≥420 nm). The most efficient CdS/VC (15 wt.%) composite photocatalyst exhibits an exceptionally high photocatalytic H2 evolution rate of 14.2 mmol h−1 g−1, up to 12 times higher than that of pristine CdS. The apparent quantum efficiency (AQE) of H2 evolution reaches up to 8.7% at 420 nm. Moreover, the CdS/VC (15 wt.%) shows good stability for H2 evolution after eight consecutive cycles of continuous light irradiation of 40 h. Most notably, the H2 evolution activity of CdS/VC is even higher than or comparable to that of platinized CdS (CdS/Pt) prepared by photoreduction or chemical reduction at the same cocatalyst loading (1 wt.%). Furthermore, VC can also serve as an efficient H2 evolution cocatalyst on various semiconductor photocatalysts (TiO2 and g-C3N4) and in a dye-sensitized photocatalytic system. Electrochemical and photoelectrochemical measurements reveal that VC can function as an efficient electrocatalyst not only to reduce the overpotential of H+/H2O reduction to H2 but also to effectively capture the photogenerated electrons of CdS for enhancing the separation efficiency of photogenerated carriers thanks to its outstanding metallic conduction, thus substantially improving the photocatalytic H2 evolution activity of CdS/VC photocatalyst. This work demonstrates that noble-metal-free VC is a promising alternative to Pt as an efficient H2 evolution catalyst for electrocatalytic and photocatalytic energy conversion.

Effect of laser radiation on the gamma activity of aqueous salt solutions containing 152Eu

We report an experimental study of the effect of laser irradiation of aqueous salt solutions containing the 152Eu isotope in the presence of nickel nanoparticles on the gamma activity of the isotope. Nickel nanoparticles are generated using laser ablation of the target in water and added to the radionuclide solution before irradiation. Two types of Nd : YAG lasers with a pulse duration of 10 ns and different repetition rates are used to irradiate the solutions. It is found that the 152Eu activity as a result of repeated irradiation of solutions by a series of pulses decreases with each irradiation cycle. The obtained results are compared with data on the effect of maser radiation with a wavelength of 8 mm on the activity of the same isotope. Possible mechanisms of the effect of electromagnetic radiation on the 152Eu gamma activity are discussed.

Searching for solar-like interannual to bidecadal effects on temperature and precipitation over a Southern Hemisphere location

Precipitation and temperature over Tucuman (26.8°S, 65.2°W), a province located in the Northwestern region of Argentina, is analyzed for the interval 1889–2018 in search of any plausible statistical associations with impacts and responses from solar variability. The aim of the study was to contribute data to the controversial issue of climate variations in response to both anthropogenic and natural forcings. The long-term behavior of Tucuman climatic series involves overall warming and augmented precipitation tendencies, possibly linked to the increasing greenhouse gases concentration or even other local man-made factors like increasing urbanization. In addition, we identified sporadic ~4 and ~8-year periodicities, and a ~20-year oscillation after the 1950–1960's. Based on the physical hint that bidecadal periodicities detected in climate parameters are probably not linked to the solar 11-year-like irradiance cycles, we expand our scope of investigations to include another effect which has been recently considered in the dynamics of large rivers as “the planetary hypothesis of the solar cycles”. This new hypothesis supposes that the barycentric dynamics of the Sun could be involved in modulations of the intrinsic solar magnetic and radiative output cycles and therefore Earth-bound climatic responses. Thus, we present a wide-ranging statistical analysis of correlation, cross spectrum, and coherence between Tucuman's climatic series and solar orbital parameters, including also the analysis of hemispheric mean temperatures. Our results show significant coherence at the ~20-year cycle, which is clearly present in the Sun's barycentric dynamic that could in turn be linked to some features of the quasi-decadal solar activity variations.