Enhancing wind turbine blade protection: Solid particle erosion resistant ceramic oxides-reinforced epoxy coatings

In recent days, it is crucial for the globe to shift fossil fuel energies to renewable energies such as hydroelectric, wind, solar, tidal, geothermal, etc. to mitigate global warming issues. Wind energy has been regarded as one of the renewable energy sources to rely on in the future. In this aspect, wind turbine blade maintenance is quite a challenge in tropical areas like India. One of the main reasons why wind turbine blades get damaged and produce less energy is solid particle erosion. In the present work, epoxy nanocomposite coatings reinforced with Al2O3, ZrO2, and CeO2 nanoparticle fillers have been applied on glass fiber reinforced polymer (GFRP) substrates using a simple spray coating method. These nanoparticles have been prepared in-house by solution combustion synthesis (SCS) route using urea, glycine, and oxalyl dihydrazide fuels, respectively. X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy have been used to characterize the materials and coatings. Epoxy coatings with different Al2O3, ZrO2, and CeO2 nanoparticle concentrations have been subjected to solid particle erosion resistance tests at impinging angles of 30°, 60°, and 90°. ZrO2 and CeO2 nanoparticle-reinforced epoxy coatings show much better resistance to solid particle erosion than Al2O3-reinforced coatings. Estimated average erosion rates are 17 and 11.3 × 10−3 mm3 g−1, respectively, for epoxy coatings with 20 and 40 wt% ZrO2 nanoparticles. However, GFRP substrate and neat epoxy (EP) coating show much higher erosion rates with respect to nanoparticles-reinforced epoxy coatings. To ascertain a correlation between H3/E2 and the solid particle erosion rates of the coatings, nanoindentation tests have been carried out. Tensile strength and initial modulus of all the coatings are found to be directly proportional to the average erosion rates, whereas, elongation at break shows an inverse relationship with the average erosion rate. This correlation of mechanical properties with solid particle erosion performance can play a critical role in the development of realistic simulation of protective coatings for wind turbine blades

Hydrodynamic performance analysis of a new hybrid wave energy converter system using OpenFOAM

In this research study, a newly proposed hybrid device of Wave Energy Converters (WEC) is investigated by considering computational fluid dynamic (CFD)-based numerical wave tanks (NWTs). The open-source CFD code solver, OpenFOAM (Open Field Operation and Manipulation) is implemented, which is numerically solved the Reynolds-averaged Navier–Stokes (RANS) equations to simulate the two-phase flow. The hybrid system consists of an Oscillating Water Column (OWC) and a point absorber (Wavestar) device installed in a shared platform. The main goal is to recognize how wave diffractions caused by the adjacent floating body could affect the rate of power absorption by the Fixed-OWC. This aim is followed by a 2D numerical analysis of three different installation configurations, variable intervals between the Wavestars' buoy and the Fixed-OWCs' front wall, in four different wavelengths with and without Power Take-Off (PTO). Finally, the efficiency characteristics of the integrated system such as free surface velocity and air pressure within the chamber, besides floating body motions are investigated and compared for the hybrid system. Although the overall assessment for 28 different case studies reveals an efficiency reduction in some cases, the superiority of this hybrid plan is recording several incremental efficiency rates

Efficient glycosylation of polyphenols via dynamic complexation of cyclodextrin and synchronous coupling reaction with cyclodextrin glycosyltransferase in water

Glycosylation is an effective way to promote the total intake of polyphenols in humans by increasing the solubility of polyphenols. In this study, an efficient glycosylation system was built via the dynamic complexation of CD with polyphenols and synchronous coupling reaction with cyclodextrin glycosyltransferase (CGTase) in water. The glycosylation efficiencies of quercetin, naringenin, rutin, resveratrol and caffeic acid were 20.9, 3.6, 2.7, 3.4 and 1.5 times higher than the non-complexed system. To quantify conversion rate and determine the rate-limiting step, the mixed product was treated with amyloglucosidase to obtain α-glucosyl rutin, which was identified as rutin 4”-O-α-D-glucopyranoside with purity of 93.6 % and yield of 34.8 % from NMR, MS and HPLC analysis. The results of half-reaction kinetics showed that the catalytic efficiencies of ring-opening of γ-CD (k1) and glycosylation reaction of rutin (k2) were 621.92 and 9.43 mM−1·s−1. The rate-limiting step was clarified for the first time, showing that the ring-opening ability of CGTase to CD was much higher than its glycosylation ability to polyphenols. It is speculated that the rapid ring-opening reaction of CD affected its dynamic complexation, releasing many polyphenols which were not utilized by CGTase in time. Therefore, adjusting the ratio and concentration of CD resulted in an optimal glycosylation molar yield of 84.1 % for rutin, which was the highest yield reported so far in water. This study established a universal system and clarified the rate-limiting step in the enzymatic glycosylation, providing theoretical guidance for efficient production of polyphenol glycosylation

Mercury bioaccumulation and assimilation in marine plankton in meltwater influenced fjords and shelf waters along the east coast of Greenland

The rapid melting of the Arctic cryosphere due to climate change will result in significant freshwater input into Arctic marine ecosystems. This might also cause the release of legacy mercury (Hg) stored in the cryosphere, increasing Hg concentration and its subsequent effects on the marine biota. However, there is scarce knowledge on the concentration of Hg in the lower trophic level organisms at the base of the Arctic pelagic food web. This is particularly important since these organisms modulate the transfer of Hg to higher trophic levels, including fish and marine mammals. We quantified the Hg concentration in two plankton size classes (> 200 and 50 - 200 μm) in coastal waters along the east Greenland coast and investigated the potential assimilation efficiency of both inorganic Hg (IHg) and methyl Hg (MeHg) in mesozooplankton and their faecal pellets in experimental incubations. The concentration of Hg in plankton ranged from 12 to 109 ng (g dw)-1 without clear trends between geographic locations or between fjords and coastal areas. Also, the concentrations did not vary between the different plankton size fractions. MeHg concentrations were lower in the mesozooplankton faecal pellets than IHg, which may be due to the higher assimilation of MeHg than IHg in mesozooplankton tissue. Our results confirm that Arctic zooplankton assimilates MeHg more efficiently than IHg and may contribute significantly to the partitioning and cycling of different Hg types in Arctic marine ecosystems

<i>Saccharomyces boulardii</i> enhances anti-inflammatory effectors and AhR activation via metabolic interactions in probiotic communities

Metabolic exchanges between strains in gut microbial communities shape their composition and interactions with the host. This study investigates the metabolic synergy between potential probiotic bacteria and Saccharomyces boulardii, aiming to enhance anti-inflammatory effects within a multi-species probiotic community. By screening a collection of 85 potential probiotic bacterial strains, we identified two strains that demonstrated a synergistic relationship with S. boulardii in pairwise co-cultivation. Furthermore, we computationally predicted cooperative communities with symbiotic relationships between S. boulardii and these bacteria. Experimental validation of 28 communities highlighted the role of S. boulardii as a key player in microbial communities, significantly boosting the community’s cell number and production of anti-inflammatory effectors, thereby affirming its essential role in improving symbiotic dynamics. Based on our observation, one defined community significantly activated the aryl hydrocarbon receptor—a key regulator of immune response—280-fold more effectively than the community without S. boulardii. This study underscores the potential of microbial communities for the design of more effective probiotic formulations

Self-aggregation and microhydration mechanisms of monoethanolamine:Far-infrared identification of large-amplitude hydrogen bond libration

The strong tendency for self-aggregation together with an intriguing mechanism for the microhydration of monoethanolamine (MEA) have been explored by low-temperature far-infrared cluster spectroscopy in doped neon “quantum” matrices at 4 K complemented by high-level quantum chemical modeling. In addition to the assignment of new mid-infrared perturbed intramolecular transitions, a distinct far-infrared transition is unambiguously assigned to the concerted large-amplitude hydrogen bond librational motion of the MEA homodimer. This observation confirms a global “head-to-head” intermolecular potential energy minimum associated with the formation of a compact doubly intermolecular OH⋯N hydrogen-bonded cyclic structure, where both monomeric intramolecular OH⋯N hydrogen bonds are broken upon complexation. By means of relative mixing ratio dependencies, dedicated annealing procedures, and selective complexation between MEA and isotopic H 2 16 O and H 2 18 O samples, distinct far-infrared transitions associated with large-amplitude intra-molecular hindered OH torsional motion and inter-molecular H2O librational (hindered c-type overall rotational) motion of the MEA monohydrate are furthermore assigned unambiguously for the first time. These spectroscopic observations reveal an intriguing metastable conformation, where H2O acts as a OH⋯O hydrogen bond donor to the hydroxy group instead of the amino group of MEA upon microhydration in the cryogenic neon environment, where the microhydration strengthens the intramolecular OH⋯N hydrogen bond of MEA due to hydrogen bond cooperativity.</p

Recent progress in mechanistic insights into cation effects on electrochemical CO₂ reduction reaction

The impact of cations in the local reaction environment has garnered attention as a crucial factor in tailoring the selectivity of CO2 reduction, although the mechanism remains under debate. Understanding these cation effects through first-principles computations can facilitate the design of efficient reaction networks and gas diffusion layers in electrolyzers. In this minireview, the latest insights into cation effects on CO2 reduction reactions are presented, covering aspects such as tuning the interfacial electric field, coordinating reaction intermediates, altering the interfacial water structure, and modulating local CO2 concentration and pH. Future research directions in this area are also discussed

Mean and maximum two dimensional wind force on an open-grown tree

The accurate quantification of the wind loading on trees is crucial for estimating the risk of tree damage. Here, we present an experimental quantification of the wind force on a rural, open-grown, deciduous tree. We first demonstrate that the amplitude and direction of the two-dimensional force vector can be estimated using two strain gauges mounted on the bottom of the stem. Secondly, we show that the dynamic response of the tree along the mean wind direction shows differences from that in the transverse direction, indicating the importance of studying both force components. Subsequently, the analysis is focused on the mean and maximum wind force over a wide wind speed range. During winter, both the mean and maximum force is described by a quadratic wind speed dependence, whereas during summer, an adjustment is needed to account for the reconfiguration of the leaves. This adjustment is parameterized using the same functional relationship for the mean and maximum force. Overall, in the wind speed range between 4–11 ms−1 the maximum wind load was 49%–66% and 52%–79% larger than the mean, during the summer and winter, respectively

Predicting the solubility of gases in imidazolium-based ionic liquids with SAFT-VR Mie EoS by a novel approach based on COSMO

This theoretical study presents a novel approach to predict the solubility of CO2 and CH4 in Ionic Liquids (ILs) under various pressures and temperatures using the predictive SAFT-VR-Mie equation of state combined with the COSMO calculations. This approach involves estimating the segment number, diameter, and segment energy of the ionic liquid using the molecular volume from the COSMO model. The 2B and 4C association schemes were examined for ILs. The predicting results obtained through this innovative strategy demonstrate excellent accuracy in predicting gas solubility. The average absolute relative deviation of the most optimal association scheme scenario ranges from 4.8 to 14.2% for CO2 and 5.7 to 6.4% for CH4, respectively, without the need for binary interaction parameters

The impact of sunlight on fouling behaviors and microbial communities in membrane bioreactors

Membrane fouling is a significant obstacle to applying membrane bioreactors (MBRs) for wastewater treatment. Here we report the impact of sunlight irradiation on membrane fouling, biopolymers, signal molecules, and microbial communities in MBRs. The degradation of signal molecules, which induce membrane biofouling, occurred through solar photolysis in batch tests. However, MBR sludge exposed to sunlight exhibited different biological behaviors creating more soluble microbial products (SMP) and signal molecules (particularly autoinducer-2). Cell lysis and deflocculation occurred when the MBR mixed liquor was exposed to sunlight. MBR fouling rates coincided with the temporal concentration profiles of SMP and signal molecules. Sunlight caused drastic changes in the MBR microbial community, stimulating the preferential growth of specific bacteria (e.g., Deinococcus Runella, Flavitalea, Glaiimonas, and Rurimicrobium). The nonmetric multidimensional scaling analysis of the MBR community structures with and without sunlight irradiation showed two distinct microbial community clusters and their reversibility. Network analysis based on Spearman's rank correlations revealed that with sunlight irradiation, fouling rates had significant positive connections with SMP proteins and the Flavitalea genus. The findings of this study demonstrate that sunlight is a considerable factor affecting membrane fouling and microbial ecology in MBRs, needing shade for fouling mitigation and sustainable operation