Search Results (181)

Surface mining in the southeastern Gobi Desert has significant environmental impacts, primarily due to the creation of large coal piles that are highly susceptible to aeolian processes. Using spaceborne remote sensing and numerical simulations, we investigated erosional processes and their environmental impacts. Our primary tool was Interferometric Synthetic Aperture Radar (InSAR) data from Sentinel-1 imagery collected between 2017 and 2022. We analyzed these data using phase angle information from the Small Baseline InSAR time series framework. The time series analyses revealed intensive aeolian erosion in the coal piles, represented as thin deformation patterns along the potential pathways of aerodynamic transportation. Further analysis of multispectral data, combined with correlations between wind patterns and trajectory simulations, highlighted the detrimental impact of coal dust on the surrounding environment and the mechanism of aeolian erosion. The lack of mitigation measures, such as water spray, appeared to exacerbate erosion and dust generation. This study demonstrates the feasibility of using publicly available remote sensing data to monitor coal mining activities and their environmental hazards. Our findings contribute to a better understanding of coal dust generation processes in surface mining operations as well as the aeolian erosion mechanism in desert environments. Full article

Glycerol, a byproduct of biodiesel, has moderate energy but high viscosity, making clean combustion challenging. Quickly evaporating fine fuel sprays mix well with air and burn cleanly and efficiently. Unlike conventional air-blast atomizers discharging a jet core/film, a newly developed swirl burst (SB) injector generates fine sprays at the injector’s immediate exit, even for high-viscosity fuels, without preheating, using a unique two-phase atomization mechanism. It thus resulted in ultra-clean combustion for glycerol/methanol (G/M) blends, with complete combustion for G/M of 50/50 ratios by heat release rate (HRR). Lower combustion efficiencies were observed for G/M 60/40 and 70/30, representing crude glycerol. Hence, this study investigates the effect of premixed methane amount from 0–3 kW, and the effect of atomizing gas to liquid mass ratio (ALR) on the dual-fuel combustion efficiency of G/M 60/40-methane in a 7-kW lab-scale swirl-stabilized gas turbine combustor to facilitate crude glycerol use. Results show that more methane and increased ALR cause varying flame lift-off height, length, and gas product temperature. Regardless, mainly lean-premixed combustion, near-zero CO and NOx emissions (≤2 ppm), and ~100% combustion efficiency are enabled for all the cases by SB atomization with the assistance of a small amount of methane. Full article

This paper investigates how stationary gravity waves generated by flow over orography enhance rainfall, with particular attention to the role of induced waves in the melting level. The findings reveal a new mechanism by which gravity wave flow focuses precipitation, amplifying rainfall intensity downwind of hills. This mechanism, which depends on the differential velocities of rain and snow, offers fresh insights into how orographic effects can intensify rainfall. A two-dimensional diagnostic model based on linear gravity wave theory is used to investigate the record-breaking rainfall of December 2015 in the Lake District of northwest England. The pattern of ascent is shown to have a qualitatively good fit to that of the Met Office’s operational high-resolution UKV model averaged over 24 h, suggesting that orographically excited stationary waves were the principal cause of the rain. Precipitation trajectories imply that a persistent downstream elevated wave caused by the Isle of Man supported a spray of seeding ice particles directed towards the Lake District, and that these grew whilst suspended in strong upslope flow before being focused by the undulating melting-level into intense shafts of rain. Full article

The article investigates the potential for producing hydrogen by combining the methods of water splitting under cavitation and the chemical activation of aluminum in a high-speed cavitation–jet flow generated by a specialized hydrodynamic reactor. The process of cavitation and water spraying causes the liquid heating itself until it reaches saturated vapor pressure, resulting in the creation of vapor–gaseous products from the splitting of water molecules. The producing of vapor–gaseous products can be explained through the theory of non-equilibrium low-temperature plasma formation within a high-speed cavitation–jet flow of fluid. Special focus is also given to the interactions occurring at the interface boundary phase of aluminum and liquid under cavitation condition. The primary solid products formed on aluminum surfaces are bayerite, copper oxides (I and II), iron carbide, and a compound of magnesium oxides and aluminum hydroxide. A high hydrogen yield of 60% was achieved when using a 0.1% sodium hydroxide solution as a working liquid compared to demineralized water. Moreover, hydrogen methane was also detected in the volume of the vapor–gas mixture, which could be utilized to address the challenges of decarbonization and the recycling of aluminum-containing solid industrial and domestic waste. This work provides a contribution to the study of the mechanism of hydrogen generation by cavitation–jet processing of water and aqueous alkali solutions, in which conditions are created for double cavitation in the cavitation–jet chamber of the hydrodynamic reactor. Full article

In view of the current situation where research on the dust diffusion laws of different dust source points is limited and the gap with the actual field situation is too large; this study employs an innovative gas–liquid–solid triphase coupling method to investigate how dust moves and spreads in the fully mechanized excavation face 431305 at the Liangshuijing Mine; focusing on both the dust field and the dust–fog coupled field. The results indicate that using the long-pressure short-suction ventilation method; dust movement in the roadway is primarily influenced by the airflow; which can be classified into vortex; jet; and return flow regions. The analysis reveals that different dust source points affect dust distribution patterns. Dust source 1 generates the highest dust concentration; primarily accumulating on the duct side and return air side of the roadway. By contrast; dust source 2’s dust mainly gathers at the heading and the front of the cutting head. Dust sources 3 and 4 show lower dust concentrations near the top of the roadway. Dust source 5 achieves the most effective dust removal; aided by airflow and a suction fan; showcasing superior dust performance. A comprehensive comparison indicates that dust source 1 has the highest overall dust concentration. Therefore; further simulation of the distribution law of dust generated at dust source 1 under the action of water mist reveals that the dust concentration near the heading face is reduced from 2000 mg/m³ under the action of single air flow to about 1100 mg/m³. At t = 5 s; the spray droplets almost cover the entire tunneling face; leading to a significant decrease in dust concentration within 10–25 m from the tunneling face. Within 40 s; both coal dust and spray droplets are significantly reduced. The field measurement results verify the accuracy of the simulation results and provide certain guidance for promoting the sustainable development of the coal industry. Full article

Firmly, the bearing capacity test of 1:1 equal ratio pillar under different constraint forms and different filling medium conditions was carried out. The results show that the binding pillar-forming effect is relatively good. The constraint ability of unconstrained, metal mesh, polyester mesh, hooked iron flat-hoop bushing, bellows, and spiral iron pipe is enhanced, in turn, and the carrying capacity is improved successfully. The homogeneity of high-water materials is better than concrete, and they have better compressibility, but their carrying capacity is relatively weak. The carrying capacity of concrete pillars is generously higher than that of high-water materials, but the compressibility is poor. Second, the migration characteristics of the surrounding rock structure of the gob-side entry retaining and the rule of side support are analyzed, the requirements of the side support are pointed out, and the side-support technology of the binding pillar is proposed. Taking Hijiata Mine’s 50108 working face gob-side entry retaining as an example, the bellows pump-filled concrete pillar is used as the side support body, supplemented by handling steel mesh and air-duct cloth, and toughness material is sprayed between the pillars to seal the goaf, meeting the requirements of side support and road stability. The pillar has the characteristics of high early strength, strong final consolidation carrying capacity, good crimping effect, high mechanism degree, fast construction speed, less concrete consumption, low comprehensive cost, etc., and it has a good application prospect in the gob-side entry retaining or rapid advanced working face. Full article

Valorization of agricultural and food by-products (agri-food waste) and maximum utilization of this raw material constitute a highly relevant topic worldwide. Agri-food waste contains different types of phytochemical compounds such as polyphenols, that display a set of biological properties, including anti-inflammatory, chemo-preventive, and immune-stimulating effects. In this work, the microencapsulation of strawberry (Fragaria vesca) plant extract was made by spray-drying using individual biopolymers, as well as binary and ternary blends of pectin, alginate, and carrageenan. The microparticle morphologies depended on the formulation used, and they had an average size between 0.01 μm and 16.3 μm considering a volume size distribution. The encapsulation efficiency ranged between 81 and 100%. The kinetic models of Korsmeyer–Peppas (R²: 0.35–0.94) and Baker–Lonsdale (R²: 0.73–1.0) were fitted to the experimental release profiles. In general, the releases followed a “Fickian Diffusion” mechanism, with total release times varying between 100 and 350 (ternary blends) seconds. The microparticles containing only quercetin (one of the main polyphenols in the plant) showed higher antioxidant power compared to the extract and empty particles. Finally, the addition of the different types of microparticles to the gelatine (2.7 mPa.s) and to the aloe vera gel (640 mPa.s) provoked small changes in the viscosity of the final gelatine (2.3 and 3.3 mPa.s) and of the aloe vera gel (621–653 mPa.s). At a visual level, it is possible to conclude that in the gelatine matrix, there was a slight variation in color, while in the aloe vera gel, no changes were registered. In conclusion, these microparticles present promising characteristics for food, nutraceutical, and cosmetic applications. Full article

When a plant is infected by a pathogen, endogenous immune responses are initiated. When the initiation of these defense responses is induced by a pathogen-associated molecular pattern (PAMP) of a pathogen, it is called PAMP-triggered immunity (PTI). Previous studies have shown that Bacillus amyloliquefaciens PMB05 can enhance PTI signals and improve disease control of bacterial soft rot and wilt in Arabidopsis thaliana. In the context of controlling bacterial wilt disease, the involvement of a mitogen-activated protein kinase (MAPK) signaling pathway has been established. Nevertheless, it remains unclear whether this pathway is also required for B. amyloliquefaciens PMB05 in controlling bacterial soft rot. In this study, A. thaliana ecotype Columbia (Col-0) and its mutants on a MAPK pathway-related pathway were used as a model and established that the ability of B. amyloliquefaciens PMB05 to control soft rot requires the participation of the MAPK pathway. Moreover, the enhancement of disease resistance by PMB05 is highly correlated with the activation of reactive oxygen species generation and stomata closure, rather than callose deposition. The spray inoculation method was used to illustrate that PMB05 can enhance stomatal closure, thereby restricting invasion by the soft rot bacterium. This control mechanism has also been demonstrated to require the activation of the MAPK pathway. This study demonstrates that B. amyloliquefaciens PMB05 can accelerate stomata closure via the activation of the MAPK pathway during PTI, thereby reducing pathogen invasion and achieving disease resistance against bacterial soft rot. Full article

The process of obtaining powders from the 5–50 μm fraction of a W-Ni-Fe system consisting of particles with predominantly spherical shapes was investigated. Experimental studies on the plasma–chemical synthesis of a nanopowder composed of WNiFe-90 were carried out in a plasma reactor with a confined jet flow. A mixture of tungsten trioxide, nickel oxide, and iron oxide powders interacted with a flow of hydrogen-containing plasma generated in an electric-arc plasma torch. The parameters of the spray-drying process and the composition of a suspension consisting of WNiFe-90 nanoparticles were determined, which provided mechanically strong nanopowder microgranules with a rounded shape and a homogeneous internal structure that contained no cavities. The yield of the granule fraction under 50 μm was 60%. The influence of the process parameters of the plasma treatment of the nanopowder microgranules in the thermal plasma flow on the degree of spheroidization and the microstructure of the obtained particles, seen as their bulk density and fluidity, was established. It was shown that the plasma spheroidization of the microgranules of the W-Ni-Fe system promoted the formation of a submicron internal structure in the obtained spherical particles, which were characterized by an average tungsten grain size of 0.7 μm. Full article

Strawberries are susceptible to various diseases during their growth, and leaves may show signs of diseases as a response. Given that these diseases generate yield loss and compromise the quality of strawberries, timely detection is imperative. To automatically identify diseases in strawberry leaves, a KTD-YOLOv8 model is introduced to enhance both accuracy and speed. The KernelWarehouse convolution is employed to replace the traditional component in the backbone of the YOLOv8 to reduce the computational complexity. In addition, the Triplet Attention mechanism is added to fully extract and fuse multi-scale features. Furthermore, a parameter-sharing diverse branch block (DBB) sharing head is constructed to improve the model’s target processing ability at different spatial scales and increase its accuracy without adding too much calculation. The experimental results show that, compared with the original YOLOv8, the proposed KTD-YOLOv8 increases the average accuracy by 2.8% and reduces the floating-point calculation by 38.5%. It provides a new option to guide the intelligent plant monitoring system and precision pesticide spraying system during the growth of strawberry plants. Full article

This work presents a study on the optical and mechanical degradation of parabolic trough collector absorber coatings produced through the spray coating application technique of in-house developed paint. The main aim of this investigation is to prepare, cure, load, and analyze the absorber coating on the substrate under conditions that mimic the on-field thermal properties. This research incorporates predicted isothermal and cyclic loads for parabolic trough systems as stresses. Biweekly inspections of loaded, identical samples monitored the degradation process. We further used the cascade of data from optical, oxide-thickening, crack length, and pull-off force measurements in mathematical modelling to predict the service life of the parabolic trough collector. The results collected and used in modelling suggested that cyclic load in combination with iso-thermal load is responsible for coating fatigue, influencing the solar absorber optical values and resulting in lower energy transformation efficiency. Finally, easy-to-apply coatings made out of spinel-structured black pigment and durable binder could serve as a low-cost absorber coating replacement for a new generation of parabolic trough collectors, making it possible to harvest solar energy to provide medium-temperature heat to decarbonize future food, tobacco, and paint production industrial processes. Full article

Softening and subsequent deformation are significant challenges in additive manufacturing of thermal-curable thermosets. This study proposes an approach to address these issues, involving the preparation of thermosetting composite powders with distinct curing temperatures, the utilization of cold spray additive manufacturing (CSAM) for sample fabrication, and the implementation of stepwise curing for each component. To validate the feasibility of this approach, two single-component thermosetting powders P1 and P2 and their composite powder C were subjected to CSAM and stepwise curing. From the sample morphology observation and deposition/curing mechanism investigation based on thermomechanical analysis and differential scanning calorimetry, it is found that severe plastic deformation occurs during the CSAM process, accompanied by heat generation, leading to local melting to promote a good bond at the contact surface of the particles and form small pores. During the progressive curing, the samples printed using C demonstrate superior deformation resistance compared with those using P1 and P2, and the curing time is reduced from 16.7 h to 1.5 h, due to the sequential curing reactions of P1 and P2 components in composite C, allowing the uncured P2 and cured P1 to alternately remain solid for providing structural support and minimizing deformation. Full article

Sandblasting materials used for dental restoration are a valuable preconditioning technique that enhances the physical properties and promotes osseointegration and cell adhesion. Triplicate groups of Ti medical grade 4 and Ti6Al4V were blasted with 16 series of various naturally occurring and synthetically produced spraying materials of controlled granulometry at three spraying durations each and two spraying pressures, and the results were tested for the determination of the surface roughness taken as an average of 80 points ±5 points for each particular series of operating parameters. SEM analysis and specific tests to see whether or not cell cultures proliferate on the treated materials were also conducted. It was found that in all cases, regardless of the spraying material or working conditions, the roughness profile achieved is a uniformly distributed one. A reduction in the blasting pressure by half led to a decrease in the roughness between 30 and 35%. The use of glass balls as blasting material led to decreased roughness and more uniformly distributed roughness values for Ti as well as for Ti6Al4V, regardless of spraying duration or applied pressure compared to other spraying materials. Blasting with olivine led to increased, as well as uniformly distributed, values, and hence the conclusion that one may control the roughness size by choosing one or another of the above materials without the need to change any other operating parameters. In the case of Ti, the achieved roughness is greater than in the case of Ti4Al6V, regardless of the blasting material; the differences are smaller the softer the sandblasting material due to the fact that Ti alloys have better mechanical properties and increased hardness compared to pure Ti. SEM analysis showed that the use of sintered hydroxyapatite as an additive to the blasting material does not necessarily lead to a substantial deposition of hydroxyapatite on the substrate materials; only traces of it were identified during the analysis. As a general conclusion, this study showed that by sandblasting Ti and Ti6Al4V with different spraying materials, one may control the surface roughness, and this technique may be an attractive method for preconditioning these materials for restorative dentistry. Full article

In recent years, inorganic nanoparticles, including calcium hydroxide nanoparticles [Ca Ca(OH)₂ NPs], have attracted significant interest for their ability to impact plant photosynthesis and boost agricultural productivity. In this study, the effects of 15 and 30 mg L⁻¹ oleylamine-coated calcium hydroxide nanoparticles [Ca(OH)₂@OAm NPs] on photosystem II (PSII) photochemistry were investigated on tomato plants at their growth irradiance (GI) (580 μmol photons m⁻² s⁻¹) and at high irradiance (HI) (1000 μmol photons m⁻² s⁻¹). Ca(OH)₂@OAm NPs synthesized via a microwave-assisted method revealed a crystallite size of 25 nm with 34% w/w of oleylamine coater, a hydrodynamic size of 145 nm, and a ζ-potential of 4 mV. Compared with the control plants (sprayed with distilled water), PSII efficiency in tomato plants sprayed with Ca(OH)₂@OAm NPs declined as soon as 90 min after the spray, accompanied by a higher excess excitation energy at PSII. Nevertheless, after 72 h, the effective quantum yield of PSII electron transport (Φ_PSII) in tomato plants sprayed with Ca(OH)₂@OAm NPs enhanced due to both an increase in the fraction of open PSII reaction centers (qp) and to the enhancement in the excitation capture efficiency (Fv’/Fm’) of these centers. However, the decrease at the same time in non-photochemical quenching (NPQ) resulted in an increased generation of reactive oxygen species (ROS). It can be concluded that Ca(OH)₂@OAm NPs, by effectively regulating the non-photochemical quenching (NPQ) mechanism, enhanced the electron transport rate (ETR) and decreased the excess excitation energy in tomato leaves. The delay in the enhancement of PSII photochemistry by the calcium hydroxide NPs was less at the GI than at the HI. The enhancement of PSII function by calcium hydroxide NPs is suggested to be triggered by the NPQ mechanism that intensifies ROS generation, which is considered to be beneficial. Calcium hydroxide nanoparticles, in less than 72 h, activated a ROS regulatory network of light energy partitioning signaling that enhanced PSII function. Therefore, synthesized Ca(OH)₂@OAm NPs could potentially be used as photosynthetic biostimulants to enhance crop yields, pending further testing on other plant species. Full article

Lithium tantalate (LiTaO₃) perovskite finds wide use in pyroelectric detectors, optical waveguides and piezoelectric transducers, stemming from its good mechanical and chemical stability and optical transparency. Herein, we present a method for synthesis of LiTaO₃ nanoparticles using a scalable Flame Spray Pyrolysis (FSP) technology, that allows the formation of LiTaO₃ nanomaterials in a single step. Raman, XRD and TEM studies allow for comprehension of the formation mechanism of the LiTaO₃ nanophases, with particular emphasis on the penetration of Li atoms into the Ta-oxide lattice. We show that, control of the High-Temperature Particle Residence Time (HTPRT) in the FSP flame, is the key-parameter that allows successful penetration of the -otherwise amorphous- Li phase into the Ta₂O₅ nanophase. In this way, via control of the HTPRT in the FSP process, we synthesized a series of nanostructured LiTaO₃ particles of varying phase composition from {amorphous Li/Ta₂O₅/LiTaO₃} to {pure LiTaO₃, 15–25 nm}. Finally, the photophysical activity of the FSP-made LiTaO₃ was validated for photocatalytic H₂ production from H₂O. These data are discussed in conjunction with the role of the phase composition of the LiTaO₃ nanoparticles. More generally, the present work allows a better understanding of the mechanism of ABO₃ perovskite formation that requires the incorporation of two cations, A and B, into the nanolattice. Full article