Fine Powder Research Articles

Phenomenological Study of the Atomization Process in Pre‐Filming Nozzles Typically Used for Steel Atomization

Liquid steel atomization using close‐coupled nozzles is highly dependent on the relationship between momentum flux ratio, gas–liquid ratio, aspiration pressure, and operating pressure of inert gases. A strong correlation between these parameters and the final powder must be assumed. Understanding these parameters, their influence on the process, and their interactions with each other is indispensable for efficient powder production. In particular, the industrial application of close‐coupled atomization nozzles, which develop a thin pre‐film on the nozzle tip, is not yet fully understood. A model experiment is presented to investigate interactions between the flow conditions of the gaseous and liquid phases, focusing on recirculation phenomena inside the atomization zone. The experiments show the influence of liquid and gas flow conditions on the spray geometry and the liquid core length, as well as the strong dependence of the liquid mass flux on the gas flow. The aspiration pressure below the liquid nozzle is sensitive to gas pressure and has a major influence on the development of the liquid core and the pre‐film, as it increases the liquid mass flux. For practical application, the results confirm an optimal operating point of interacting system parameters, which leads to high‐quality atomization with minimal use of resources.

Industrial manufacturing method and characterization of Ayurvedic marine drugs: mother pearl, cowry, coral and pearl

Introduction: Ayurvedic marine drugs derived from mollusc shells and coral are regularly used by Ayurvedic physicians to treat several disease conditions like acid peptic disease, irritable bowel syndrome, osteoporosis, etc. However, standard operating procedures for manufacturing these drugs and their complete characterization have not been published in the Ayurvedic Formulary and Ayurvedic Pharmacopeia of India to date. Methods: Present study describes the traditional manufacturing process and thorough characterization using classical and advanced analytical tools. The raw materials characters, in-process parameters, and finished product specifications have been elaborated to develop monographs. Especially, the identity and purity of raw coral and pearl were checked by Raman Spectroscopy and Energy Dispersive X-ray Fluorescence analysis. Results: In the finished product analysis, the X-Ray Diffraction study revealed that incineration after trituration with Aloe barbadensis leaf pulp or rose water converted the aragonite phase of calcium carbonate into calcite phase in mother pearl, cowry, and pearl while the calcite form of raw coral was retained. The prominent bands around 1390, 870, and 712 cm−1 detected by Fourier Transform-Infrared Spectroscopy and mass loss between 39–44% (w/w) revealed by thermogravimetric analysis confirmed the carbonate form of these calcium-based drugs. The finished products were very fine grayish-white powders constituted by irregularly shaped nano-micro particulate calcium carbonate exhibiting particle size between 600 nm (D10 value) to 1.2 µm (D90 value). Conclusion: The quality control and assurance achieved in this study may be further utilized by the pharmaceutical industries to manufacture quality marine drugs and conduct efficacy studies.

Arch formation mechanism and discharge process of cohesive fine powder in a vibrated silo

The arch formation mechanism and discharge process of a very cohesive fine powder (calcium carbonate) in a vibrated silo was investigated by experiments and discrete element method (DEM) simulations. An experimental setup is built to study the flow behaviors with the proposed image-based flow rate measurement method. A cohesive DEM model is used to investigate the dynamic behaviors of the powder bed. Results indicate that the arch formation depends on the vibration acceleration amplitude and is slightly affected by the frequency. The powder discharge flow rate increases with vibration acceleration amplitude and decreases with frequency. When the acceleration amplitude exceeds 15 g, the flow rate tends to stabilize. When the acceleration amplitude exceeds 1 g, there is separation and collision between the powder bed and the silo bottom. This collision leads to a significant increase in the contact force.

In Silico and In Vitro Evaluation of Bioactive Compounds of Vallisneria spiralis L. against Candida albicans

Background This study focused on the extraction, isolation, characterization, and molecular docking of phytochemicals from Vallisneria spiralis L. to determine its antifungal activity. Natural products and structural analogs have always played an important role in pharmacotherapy, particularly in the treatment of infections and malignancies. Methods Vallisneria spiralis L. leaves were pulverized into a fine powder and extracted using a Soxhlet apparatus, and the crude chloroform extract was separated by flash column chromatography. Thin-layer chromatography was used to assess the obtained fractions. Infrared spectra were obtained using a Perkin Elmer spectrometer. NMR spectra were collected using a Bruker spectrometer. Qualitative phytochemical investigations were performed to identify compounds in the extracts. The susceptibility of the test compound to Candida albicans was assessed using disk diffusion. A docking study was conducted to dock the three-dimensional structures of the extracted phytocompounds of Vallisneria spiralis L. into the receptor site of the target proteins using Autodock software. MD simulations were used to study the dynamic behavior, conformational changes, and stability of the proteins using the top three hit chemicals. Results These results suggest that Vallisneria spiralis L. extract contains various phytoconstituents, including carbohydrates, tannins, flavonoids, steroids, terpenoids, and glycosides. The distinctive functional groups of the extract were identified using a Fourier-Transform Infrared (FTIR) spectrophotometer. Nuclear Magnetic Resonance (NMR) spectroscopy was used to determine the structures of the isolated and purified extracts. The antifungal activity of Vallisneria spiralis L. extract against Candida albicans was found to be significantly stronger at a concentration of 200 mg/mL. Conclusion The findings of the study were obtained using in vitro and in silico methods to investigate the antifungal effect of Vallisneria spiralis L., which highlighted it as a potential natural antifungal treatment for Candida infection, which could be further investigated.

Study on the Preparation and Performance of Lightweight Wallboards from MSWIBA Foam Concrete.

To reduce land use and avoid further pollution, incineration for power generation has become the main method for municipal solid waste treatment. This research focused on the potential for transforming Municipal Solid Waste Incineration Bottom Ash (MSWIBA) into a finely ground powder. The impact of the powder's fineness and the amount of water used on its effectiveness was analyzed using a method called grey theory. MSWIBA was used as a partial substitute for cement in making MSWIBA foam concrete and lightweight wall panels. By modifying the fineness and water utilization of the recycled micro-powder, its maximum activity index can be increased to 90.1. This study determined the influence of factors including apparent dry density, water-cement ratio, foaming agent dilution ratio, and admixture dosage on the strength of the recycled foam concrete, and established the optimal mix ratio. This study employed a combination of physical experiments and numerical simulations to elucidate the impact of panel material, core layer thickness, and layer sequence on sound insulation performance. The simulation results were in close agreement with the experimental findings.

Carbon Dioxide Adsorption by Variation in Operating Parameters of Sound Assisted Fluidization Using Coal Based Fine Activated Carbon

This research delves into the promising domain of CO2 capture through fine solid activated carbon adsorbent, offering a more energy-efficient alternative to traditional adsorption methods. The central challenge addressed here is the utility of cheaper CO2 adsorbent, fine powder materials whose properties can be precisely tailored via molecular-level fictionalization. Equally vital is selecting an optimal fluidizing column configuration that maximizes CO2 interaction with adsorption particles and enhances adsorption efficiency. The proposed solution is a fluidized bed column uniquely equipped with integrated acoustic vibrations to counteract interparticle forces common in fine powders. For adsorption evaluations, sound-assisted fluidized-bed experimentation on a laboratory size was set up. Adsorbent material activated carbon made up of coal underwent rigorous testing between a range of 20 Hz-200 Hz and 20 dB-135 dB. Results reveal the beneficial effects of acoustic enhancement of fluidization quality and adsorption efficiency, increased adsorption capacity, enhanced bed utilization, and accelerated adsorption rates. Extensive research has been conducted on the detailed effects of major operational variables on adsorption performance, notably frequency, sound intensity, and minimum fluidization velocity. The findings highlight the pivotal role of particle size with mean size 75 microns range as a determinant of adsorption capacity at 100 Hz and 125 dB. At the end of experimentation, the adsorbent considered for the experiment is compared to the study adsorption capacity at operating conditions. The research concludes with a discussion on the effects of influencing parameters for adsorption on employing sound vibrations using fluidization technique adsorption for CO2 capture.

Elemental analyses of feldspathic to basaltic soils and rocks on the moon using laser-induced breakdown spectroscopy

In-situ analysis of major elements using laser-induced breakdown spectroscopy (LIBS) is essential for future lunar landing missions, yet its performance under lunar conditions remains not fully understood. This uncertainty arises from the absence of an atmosphere and the diverse range of surface materials, which vary in chemical composition from anorthosites to basalts, and in physical properties from fine regolith to boulders. To address these challenges, we developed and cross-validated a multivariate LIBS calibration model by measuring 169 compressed fine powders of geologic samples under vacuum. These samples fully encompass the bulk composition range of lunar meteorites. We investigated the applicability of the model to a wider range of samples by measuring lunar meteorites, terrestrial anorthites, and lunar simulants in various physical forms, including rock chips and soils with different grain sizes and bulk densities. For powder samples, the quantification accuracy, assessed using root mean squared error (RMSE), resulted in 2.5 wt% SiO2, 0.25 wt% TiO2, 1.2 wt% Al2O3, 1.3 wt% MgO, 1.2 wt% CaO, 0.33 wt% Na2O, 0.47 wt% K2O (0.060 wt% K2O in the <1 wt% range), and 1.5 wt% T-Fe2O3. For rock chip samples, the RMSEs were 3.1 wt% SiO2, 0.32 wt% TiO2, 2.2 wt% Al2O3, 2.5 wt% MgO, 2.0 wt% CaO, 0.33 wt% Na2O, 0.089 wt% K2O, and 2.1 wt% T-Fe2O3. Despite significant differences in physical conditions between powders and rocks, their RMSEs remained consistent within a factor of two. Changes in grain size or bulk density of soils had relatively minor effects on the RMSE. These RMSEs confirm that the quantification accuracy of LIBS is sufficient to distinguish the subgroups within the lunar anorthosite suite (e.g., anorthosites vs. norites) and basalts (e.g., high-Ti vs. low-Ti) across a range of soil types, from coarse to fine and from loose to compact, as well as rocks. Furthermore, our analysis shows that LIBS can differentiate between “purest” and “pure” anorthosites (98 and 95 vol% plagioclase, respectively) based on the 3σ detection limits of Mg and Fe lines. These capabilities of LIBS align well with the goals of future lunar exploration, such as locating ilmenite-rich soils for resource extraction, detecting purest anorthosites to understand early lunar evolution, and identifying noritic impact melts to refine lunar chronology. Overall, our results demonstrate that LIBS serves as a versatile tool for rapid geochemical characterization on the Moon.

Investigation and quantification of composition variability in urinary stone analysis.

To investigate the variability in urinary stone composition analysis due to sampling and suggest potential solutions. We collected 1,135 stone fragments from 149 instances that had undergone a stone removal at Hanoi Medical University Hospital from January 2022 to August 2022. Each fragment was ground into fine powder and divided into separate specimens if the amount was abundant. For composition analyzing every specimen, Fourier transform infrared spectroscopy was performed. The composition of a given fragment was the average of its belonging specimens. The variability in composition was assessed on the fragment level (i.e., between fragments of an instance). We defined an instance as "significantly variable" if the maximum difference in any composition across its belonging fragments was equal to or greater than a given threshold. On average, there were 7.6±3.3 stone fragments per instance and 2.3±0.5 specimens per fragment. We found that the variability could be substantial on the fragment level. Eighty-nine (69.5%) and 70 (54.7%) out of 128 multiple-component instances were significantly variable if the threshold was set at 20% and 30%, respectively. The variability of an instance on the fragment level was correlated with the size of fragment and the number of components. Our study demonstrated the significant variability in urinary stone composition and showed that it correlated with the size and the impurity of samples. Mapping denotation while sampling and analyzing as well as reporting the composition of individual fragments could be valuable to reduce potential variability.

Fabrication of graphene oxide/ammonium molybdophosphate composite membrane for decontamination of cesium ions from seawater

Efficient separation of radioactive cesium ions (Cs+) from complicated aqueous environmental media has attracted considerable interest, especially seawater. Ammonium molybdophosphate (AMP) is regarded as a promising adsorbent for Cs+, but its fine powder dramatically inhibits the potential for practical applications. Herein, graphene oxide (GO) was utilized as a support for the in-situ growth of AMP, and after vacuum filtration, GO/AMP composite membrane was successfully fabricated. It was found that the GO/AMP membrane exhibited excellent adsorptive filtration performance (47.3 L m−2h−1 bar−1 water flux and 99.2 % rejection for Cs+ with 20 ppm initial concentration, 30 mL feed solution). Influent pH and coexisting metallic ions had scarcely effects on Cs+ rejection. Over five cycles, the water permeability and Cs+ rejection remained essentially unchanged. Moreover, the decontamination of Cs+ from real seawater was demonstrated with the rejection ratio as high as 87.4 % and a relatively inhibitory flux of 14 L m−2h−1 bar−1. Based on FT-IR, XPS, and EXAFS analyzes, the rejection of Cs+ was mainly ascribed to the exchange of NH4+ in AMP with Cs+ in solution, and an inner-sphere coordination of Cs+ rather than a weak outer-sphere interaction between hydrated Cs+ ions and adsorbent occurred.

Sustainable lignin-based powder coatings doped with ZnO displayed excellent UV resistance properties

Sustainable lignin-based powder coatings doped with ZnO displayed excellent UV resistance properties

An experimental and theoretical study on effects of particle size distribution on flowability and film properties of organic powder coatings

An experimental and theoretical study on effects of particle size distribution on flowability and film properties of organic powder coatings

Synthesizing a novel cerium-modified graphene powder to achieve long-term anticorrosion performance of epoxy powder coatings

Synthesizing a novel cerium-modified graphene powder to achieve long-term anticorrosion performance of epoxy powder coatings

Lasers Powder Coatings Quickly and Energy-Efficiently

Lasers Powder Coatings Quickly and Energy-Efficiently

Oil-based drilling cutting pyrolysis residues-recycled fine powder sintered ceramsite: Basic properties, microsintering mechanism, lightweight concrete application and heavy metals solidification

Oil-based Drilling Cutting Pyrolysis Residue (ODPR) is a waste produced during oilfield drilling using oil-based mud. Recycled Fine Powder (RFP) consists of particles less than 0.16 mm, crushed and sieved from waste concrete. China's solid waste is characterized by high production, low utilization rates, and high pollution levels. This study explores the feasibility of preparing ceramsite from ODPR and RFP. By examining the effects of varying temperatures and proportions on the macroscopic and microscopic properties of ODPR-RFP ceramsite (ORC), the optimal process was determined: ODPR: RFP = 7:3, 2 % borax flux, 10 minutes ball milling, 1200℃ sintering temperature, and 30 minutes insulation. The resulting ORC, with a bulk density of 1120 kg/m³, cylinder compression strength of 10.50 MPa, and water absorption rate of 7.8 %, meets the "Lightweight aggregates and its test methods (GT/B17431.2)" standard. Batch production of ORC products of various sizes was conducted to evaluate their practical application in LC30 lightweight aggregate concrete. Replacing the aggregate in lightweight concrete with ORC yielded a concrete with excellent mixing performance, reaching a maximum strength of 31.2 MPa after 7d and 44.8 MPa after 28d. The damage pattern of ORC lightweight concrete is characterized by longitudinal splitting, with varied crack initiation and expansion paths. In the interfacial transition zone of ORC concrete, the ORC form a strong bond with the cement mortar, enhancing the strength of the lightweight concrete. Additionally, the leaching of heavy metals (HMs) from the ORC was examined to assess potential environmental pollution. The results indicated that preparing ORC from these two types of solid waste can effectively immobilize HMs, with a solidification rate of up to 92.10 %. Pb with high content is mainly solidified in the form of solid solution to form (Ba, Pb) SO4. The ecological risk assessment method for HMs shows that using this solid waste and process to prepare ORC does not pose HMs risks and is an environmentally friendly building material.

Increasing particle-size by air-flow modification – An experimental study

Ambient particulate are characterize by submicron particles that may penetrate deep into the lungs, where they become harmful due to their morphology and composition, or due to their role as carriers of harmful chemicals or biological agents. Particle filtration technologies have in general a lower efficiency at diameter size around 0.1–0.3 μm. This study examines the concept of particle grouping as a means to overcome this size-gap, for improving air purification or filtration systems. The grouping manipulation is induced by a controlled rotating valve which creates a sinusoidal flow in the experimental tube, and by modules with varying diameter, forcing a wavy flow. Fine particles with a known size distribution which are introduced into the manipulated flow, exhibit groups of particles in the outflow, hence increase the effective size of the particles. Former successful studies were performed with high flow velocity and particle load of industrial duct and car engine outflow, while in the current study smaller particle loads representing ambient to indoor levels are in operation. Although the low velocity and particle load are challenging, this study shows a promising shift of the particle size distribution from a peak at 0.2–0.3 μm, towards larger particle diameters. Fine powder of dolomite is used in this study and preliminary results of adhesion experiments related to dolomite are also reported.

Graphene oxide with different oxygen content produced from natural and synthetic graphite sources for methylene blue sorption

Graphene oxide (GO) is of great interest due to its unique structure and properties and potential applications, including water purification. In this work, we report the synthesis of GO samples with different oxidation degree from two different sources of graphite using Hummers method. Natural flake graphite with a high degree of crystallinity, and synthetic fine powder graphite were used. All produced materials were characterized by CHNS analysis, X-Ray Diffractive analysis (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). It was shown that the oxidation process for natural and synthetic graphite sources proceeds in different ways. The factors, affecting for the structure and properties of GO are the degree of crystallinity and the lateral size of the graphite flakes. The sorption activity of underoxidized, normally oxidized and overoxidized GO was compared toward the methylene blue (MB) dye in aqueous solution. The most efficient sorption was registered for GO produced from synthetic graphite with the use of 2.0 and 4.5 wt. eq. KMnO4. The sorbents removed 94 % and 100 % of MB from the solution, respectively, in approximately 10 min. Our results reveal that the structure and sorption properties of GO can be tuned by varying the oxidation degree as well as the graphite source, which may open the way to new developments in the GO-based materials applications.

The effects of raw materials particle sizes on the solid-state reaction progress, morphology and magnetic properties of M-type strontium hexaferrites

In this work, the effects of SrCO3 and Fe2O3 particle size on the reaction process, morphology and magnetic properties of M-type strontium hexaferrites (SrM) have been further studied. Pure strontium hexaferrite magnetic sample based on SrCO3 and Fe2O3 molar ratio of 1:6 has been successfully prepared at 1150 °C. The results indicated that Fe2O3 particle size was the main factor of affecting the formation of SrM, a pure SrM phase magnetic sample was able to obtain at lower calcination temperatures by using fine Fe2O3 powder as raw material, and at the same calcination temperature, a sample using fine Fe2O3 powder as raw material was able to obtain pure SrM phase magnetic sample with shorter holding time. When the mean particle size of Fe2O3 was below 60 nm, a pure SrM phase magnetic sample was able to form at 1150 °C at a molar ratio of 1:6 of SrCO3 and Fe2O3. In this case, the magnetic parameters of the sample with the optimum magnetic parameters were saturation magnetization MS = 77.8 emu/g and coercive force HC = 4122 Oe. And the solid-state reaction process of the corresponding samples was slightly faster when the mean particle size ratio of Fe2O3 and SrCO3 was between 0.35 and 0.36. Assuming that a SrCO3 particle is surrounded by Fe2O3 particles, it can be inferred that the corresponding molar ratio of Fe and Sr of the nearest raw material particles is between 3.6 and 3.8.

A Volcanic Tephra-Based Non-Portland Cement System for Well Cementing Sustainability

Summary Although Portland cement (PC) is extensively used in oil and gas well cementing for different applications such as zonal isolation and plugging, it does have technical and environmental drawbacks. PC is responsible for approximately 8% of global carbon dioxide (CO2) emissions and consumes massive energy while manufacturing. Geopolymer cements, which are made from nontraditional, non-PC ingredients, have garnered attention as potential candidates for oilwell cementing due to their low CO2 footprint and less energy consumption. This work introduces a proposed non-PC system that totally replaces PC using volcanic tephra (VT) and an alkaline solution. The study started by collecting, crushing, and sieving VT until it became a fine VT powder. Rheological properties, thickening time, unconfined compressive strength, and dynamic elastic properties were also assessed for the developed formulation. Sedimentation evaluation was conducted using the API method and nuclear magnetic resonance (NMR). The experimental evaluation included thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray fluorescence, and particle-size distribution. The developed 15.8 ppg VT-based geopolymer used a 4 M sodium hydroxide (NaOH) solution and VT only. The 24-hour unconfined compressive strength was 2,900 psi, with a Poisson’s ratio of 0.29 and a Young’s modulus (YM) of 1.11 Mpsi. The developed formulation had a thickening time of 3.5 hours at a bottomhole circulation temperature of 170°F without using any retarder. The density variation between the top and bottom sections was only 0.65%. This work introduces a new cement system made of VT without any processing except milling and sieving. This reduces the overall carbon footprint and costs of oilwell cementing operations.

Investigation of Proximate Composition and Bioactive Components in Banana (Musa acuminata) Peels Using Advanced Analytical Techniques

Background: Banana peels, often considered waste, contain valuable nutrients and bioactive compounds. This study investigates the proximate composition and bioactive components of banana (Musa acuminata) peels using advanced analytical techniques. Materials and Methods: Banana peels were collected from household wastes and processing facilities, washed, dried, and ground into fine powder. Proximate analysis was performed to determine moisture, carbohydrate, ash, crude fiber, protein, and crude fat content using standard methods. Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FT-IR) were employed to identify and characterize bioactive components and functional groups. Results: The proximate composition revealed moisture (7.36 ± 0.37%), carbohydrate (23.15 ± 0.05%), ash (12.11 ± 0.09%), crude fibre (30.53 ± 0.77%), protein (16.42 ± 0.45%), and crude fat (10.43 ± 0.67%). GC-MS analysis identified various bioactive compounds, including 13-Docosenoic acid methyl ester (12.67%), 1-Docosene (12.63%), and Octadecanal (9.45%). FT-IR analysis indicated the presence of functional groups such as alkane (2746.688 cm^-1), ester (1888.360 cm^-1), and primary amine (3514.793 cm^-1). Conclusion: Banana peels possess significant nutritional and bioactive components, making them a potential resource for various industrial applications. The study highlights the importance of valorizing banana peels for nutritional and therapeutic uses.

Establishment and evaluation of dynamic viscoelasticity constitutive model for asphalt mixtures based on PCA model: Utilizing coal-based synthetic natural gas slag and phosphogypsum whisker as substitute fillers

To promote the secondary utilization of solid waste in asphalt pavement and reduce resource waste and environmental damage, the fine solid waste powder from the secondary treatment of solid waste was used as a substitute filler to prepare asphalt mixtures. To more precisely characterize the effects of filler type and substitution ratio on the dynamic viscoelastic mechanical characteristics of asphalt mixtures, the dynamic modulus test was conducted on asphalt mixtures, while the dynamic modulus master curve of asphalt mixtures was established based on the time-temperature equivalent principle and the Sigmoidal function. The improved generalized Sigmoidal (IGS) model, five-parameter fractional Zener (FFZ) model, six-parameter fractional Zener (SFZ) model and ten-parameter fractional Zener (TFZ) model were used to construct the shrinkage frequency curves of different asphalt mixtures under different constitutive relationships, whereas the applicability of the constitutive models was further evaluated by the principal component analysis (PCA) model. The research results showed that the dynamic modulus and phase angle of the mixture exhibited a similar change rule with the variation of temperature and frequency, and the use of solid waste-based fillers could effectively reduce the effect of frequency variation on the viscoelasticity of the mixture. The dynamic modulus master curve constructed by Sigmoidal function could accurately describe the functional relationship between the dynamic modulus with loading frequency and temperature, and the variation trend of dynamic modulus in a wider frequency range was flattened with the increase in frequency, and this change rule was not affected by the substitution ratio of the filler, while the use of solid waste-based filler could reduce the dependence of the mixture on the temperature. Compared to several fractional constitutive models, the IGS model exhibited a higher fitting accuracy for the dynamic viscoelasticity of several mixtures, and with the use of solid waste-based fillers, the deviation of fitting curves gradually decreased. A comparative study showed that the fractional constitutive model was difficult to accurately describe the dynamic viscoelasticity of the mixture, and the IGS model was preferred to be recommended as a calculation model to investigate the constitutive relationship on the dynamic viscoelasticity of the mixture.