Fine Powder Research Articles

Unravelling the emulsifying properties of unfractionated plant powders: From interface to bulk

Crude plant-based by-product powders can stabilise emulsions. Their chemical composition varies substantially depending on both the source plant and the manufacturing process, resulting in different emulsifying properties. This diversity was assessed by studying the emulsifying properties of three chemically different by-products (apple seed cake: protein-rich, apple pomace: non-protein soluble-rich, and liquorice root: mostly water-insoluble) ground into fine and coarse powders. The properties (droplet size, particle anchoring ratio, rheological properties) of the powder-stabilised emulsions were monitored for one month and linked to powder suspensions properties assessed in the presence and absence of solid particles. The interfacial scale was emphasized as the primary location to study the interactions between mixed emulsifiers. The interfacial properties of the powders, and especially the competition between solid particles and soluble compounds, were successfully linked to emulsions properties. Protein-rich powder-stabilised emulsions contained smaller droplets, whose diameter varied slightly with particle size, confirming soluble macromolecules dominance at interfaces. With the soluble powder, particles and soluble macromolecules acted synergistically at both interfacial and bulk scales, indicating mixed interfaces. Particle size determined the properties of the emulsions stabilised with insoluble powder, suggesting interfaces mostly composed of solid particles. Solid particles ensured the gravitational and thermodynamic stability of all powder-stabilised emulsions.

The investigation on the ceiling of inlet velocity regarding to fine particle separation in a cyclone

The maximum efficiency inlet velocity (MEIV) serves as the upper limit for the inlet velocity that defines the separation efficiency in cyclone design and operation. In this paper, a combination of numerical and experimental methods is used to study MEIV. Experimental findings indicate that the MEIV is 22 m/s for a median particle size of 12.39 μm (coarse powder) and 35 m/s for a median particle size of 2.93 μm (fine powder). Meanwhile, the amount of escaped fine powder is reduced by 25% compared to that at an inlet velocity of 22 m/s. Computational fluid dynamics (CFD) simulations have shown that the inconsistency between tangential and axial velocity growth of inlet velocity with respect to various powder diameters can explain this phenomenon. As the inlet velocity increases, the peak axial velocity exhibits a stepwise increase. When the peak value remains constant, the peak width increases. This phenomenon is called stagnation of the axial velocity. During the axial velocity stagnation step, the residence time of back-mixed particles vary. In contrast, the tangential velocity increases linearly with the inlet velocity, resulting in an enhanced secondary separation of the inner vortex. Both factors hinder the escape of fine particles due to entrainment by a rapid upward airflow. The inlet velocity range corresponding to the stagnation step of the fine powder is larger than that of the coarse powder. Therefore, the MEIV of the fine powder is higher.

Preparation and Characterization of Duplex PEO/UV-Curable Powder Coating on AZ91 Magnesium Alloys

Preparation and Characterization of Duplex PEO/UV-Curable Powder Coating on AZ91 Magnesium Alloys

Study on the effect of recycled fine powder on the properties of cement mortar and concrete

With the development of the city, a large amount of waste concrete and broken bricks will be produced. The development and utilization of waste concrete will produce recycled coarse aggregate, recycled fine aggregate and recycled powder. Therefore, this paper studies the influence of these powders on the performance of cement mortar and cement concrete, and analyzes the performance of the powder instead of cement and fine aggregate. The results show that the strength of the mortar is greater than the reference strength after the powder is mixed, and the powder substitution rate is 17 %. Replacing cement with 14 % powder and replacing fine aggregate with 20 % powder, that is, the content of powder is 34 %. After replacing recycled fine aggregate with a certain proportion of recycled powder, the strength of concrete can be improved under the premise of less reduction of workability.

3D printing of cementitious composites with seashell particles: Mechanical and microstructural analysis

Seashells are abundantly available as waste products from the seafood industry and from coastal areas. Accordingly, processed shells can be used to partially replace aggregates in traditional concrete. This paper investigates the effects of different proportions of seashell particles on the mechanical and microstructural properties of 3D-printed cementitious composites. The seashells were crushed and milled to be transformed into seashell particles, replacing the river sand at 15 wt% and 30 wt%. It was found that when the seashell particle content increased to 15 wt% and 30 wt%, the mechanical strengths all decreased significantly, which could be attributed to the increasing volumetric proportion of voids and the lower elastic modulus of seashell particles compared to river sand. However, when the seashell particle proportion further rose from 15 wt% to 30 wt%, the mechanical strengths did not continue decreasing substantially. Instead, the compressive and indirect tensile strengths nearly levelled off with minor fluctuations. Based on the microstructural analysis results, it was inferred that the fine seashell powders as part of the seashell particles, which were comprised of aragonite-based calcium carbonate, participated in the cement hydration process that could help with microstructure densification of the cement matrix. This positive effect brought by the fine seashell powders was thought to prevent the further weakening of mechanical properties. Overall, this study aims to understand the role of seashell particles on the mechanical performance of 3D-printed cementitious composites from the perspectives of microstructural characteristics, further promoting the utilisation of waste seashells in 3D concrete printing applications.

Effect of Exhaust Pipe Size on Separation Efficiency of Cyclone Separator Used in Power Plant

In order to grasp the influence of exhaust pipe size on cyclone flow fields and improve the recovery and utilization rate of coal powder in power plant, the flow characteristics and the separation capacity of the fine coal powder separator in power plant were investigated through numerical simulation. The Reynolds stress model was employed to model the turbulent flow. The Eulerian-Lagrangian computational procedure was used to predict particles tracking in the cyclone. The particle trajectories were simulated using the discrete random walk. Five cyclone types with different insertion lengths of the exhaust pipe at the same other geometric dimensions were considered. It was found that tangential velocity played a dominant role in the radial distribution of particles, which was mainly represented by Rankine vortex. When the insertion length of the exhaust pipe was increased from 1638 mm to 5100 mm, the grade efficiency of 5–12 μm particles was increased by 19%, and the pressure drop reduced by 8%.

Additive Manufacturing of Biodegradable Molybdenum - From Powder to Vascular Stent.

Magnesium, iron, and zinc-based biodegradable metals are widely recognized as promising candidate materials for the next generation of bioresorbable stent (BVS). However, none of those metal BVSs are perfect at this stage. Here, a brand-new BVS based on a novel biodegradable metal (Molybdenum, Mo) through additive manufacturing is developed. Nearly full-dense and crack-free thin-wall Mo is directly manufactured through selective laser melting (SLM) with fine Mo powder. Systemic analyses considering the forming quality, wall-thickness, microstructure, mechanical properties, and in vitro degradation behaviors are performed. Then, Mo-based thin-strut (≤ 100µm) stents are successfully obtained through an optimized single-track laser melting route. The SLMed thin-wall Mo owns comparable strength to its Mg and Zn based counterparts (as-drawn), while, it exhibits remarkable biocompatibility in vitro. Vessel related cells are well adhered and spread on SLMed Mo, and it exhibits a low risk of hemolysis and thrombus. The SLMed stent is compatible to vessel tissues in rat abdominal aorta, and it can provide sufficient support in an animal model as an extravascular stent. This work possibly opens a new era of manufacturing Mo-based stents through additive manufacturing.

First report of Macrophomina phaseolina causing сharcoal rot in soybean (Glycine max (L.) Merr.) plants in Uzbekistan.

The soybean production area is expanding in Uzbekistan. Soybeans were planted on an area of 10 thsd ha and the harvest amounted to 30 thsd metric tons in 2023 (IPAD, https://ipad.fas.usda.gov/countrysummary). Macrophomina phaseolina (Mp) is a soil- and seed-borne fungal pathogen causing economically important diseases of legume crops (Pennerman et al. 2024). Drought stress and a warm climate are favorable to this pathogen (Irulappan et al. 2022). Under these conditions, its microsclerotia survive for a longer period and become more virulent (Chamorro et al. 2015). In August 2022, typical symptoms of charcoal rot were observed in about 25% of "Orzu" soybean cultivar affecting 6 ha located on the experimental base "Durmon" of our institute. Diseased plants displayed the following charcoal rot symptoms: leaves turn yellow, then wilt, die, and remain attached to the plant; the lower portion of the stem and tap root have a light gray or ashy black discoloration; tiny black specks on the lower stem and root; after splitting the stem, it has the appearance of fine charcoal powder. In order to determine the causal agent of these symptoms, a total of 17 diseased plants were collected from focal lesions in soybean plantings. From each plant, twelve sections of stem and root tissue were selected, cut into small 5-mm pieces, and surface sterilized with 1% sodium hypochlorite for four minutes, then rinsed three times with sterile distilled water. The disinfected tissues were dried on sterile filter paper for 5 min and placed on PDA Petri plates, which were incubated in an incubation chamber for 3 days (16 h light (26oC) and 8 h dark (18oC)). Fungi were subsequently subcultured on PDA and incubated for 7 days to obtain pure cultures. Six monohyphal colonies were purified. The colonies showed dense growth, with a gray initial mycelium becoming darker with aging. After 8 days on PDA, black-colored microsclerotia with spherical to oblong shapes were observed. On average, they measured 60 µm in width and 130 µm in length (n = 30). From six isolated monohyphal colonies, one has been chosen for molecular-genetic identification. Molecular-genetic analysis was conducted by amplification and sequencing of the ITS region with the ITS1 and ITS4 primers (White et al. 1990). The resulting sequence was deposited in the NCBI database under accession number OQ073450. After BLAST analysis (Altschul et al. 1990) it was 100% identical with the reference sequences of Mp (accession MT039671, MT039663 and MH496040) isolated in sugar beet, maize and sunflower, respectively, from Serbia. In order to verify the pathogenicity, soybean seedlings (cv. Orzu) were dipped into spore suspension (1 × 107 spores/ml) of sequenced strain R-17 for 1 minute and transferred to a 15 cm diameter plastic pot with 350 g of sterilized soil mix. After 25 days, the inoculated plants showed classic charcoal rot symptoms, while the control plants remained healthy. The pathogen was successfully reisolated from the infected seedlings onto PDA, fulfilling Koch's postulate. The identity of the re-isolated strain was confirmed by morphological features and sequencing of the ITS region. It should be noted that in Uzbekistan, Mp has not been documented in any plants. Therefore, according to our knowledge, this is the first report of this fungus affecting soybean plants in Uzbekistan. Since molecular-genetic analysis of the R-17 strain showed clustering with strains from Serbia, we speculate that there may have been a recent introduction of Mp from Serbia into Uzbekistan. This assumption is additionally confirmed by the fact that Serbia is the largest seed exporter in Uzbekistan. The increase in charcoal rot disease poses a major challenge to soybean production in Uzbekistan. Understanding the genetic diversity of Mp can be utilized to manage this disease, improve soybean yield, and help soybean breeding programs in Uzbekistan.

Exploration of improved, roller-based spreading strategies for cohesive powders in additive manufacturing via coupled DEM-FEM simulations

Spreading of fine (D50 ≤20μm) powders into thin layers, such as required by layer-wise additive manufacturing (AM) processes, typically requires a mechanism such as a roller that provides adequate shear and compression to overcome the cohesive forces between particles. We explore improved, roller-based spreading strategies for highly cohesive powders using an integrated discrete element-finite element (DEM-FEM) framework. We find that optimal roller-based spreading, quantified by maximum packing density and uniformity of layer thickness, relies on a combination of surface friction of the roller and roller kinematics, e.g., counter-rotation or angular oscillation, that impart sufficient kinetic energy to break cohesive bonds between powder particles. However, excess rotation speed (or shear stress) can impart excessive kinetic energy to the powder causing ejection of particles and a non-uniform layer, suggesting the existence of a process window of optimal spreading parameters. Interestingly, the identified optimal parameters for both investigated roller kinematics, i.e., angular velocity for counter-rotation as well as angular frequency and amplitude for rotational oscillation, result in a very similar range of roller surface velocities, suggesting roller surface velocity as the critical kinematic parameter. When these conditions are chosen appropriately, layers with packing fractions beyond 50% are predicted for layer thicknesses as small as ∼2 times D90 of the exemplary cohesive powder, and the layer quality is robust with respect to substrate adhesion over a 10-fold range. The latter is an important consideration given the spatially varying substrate conditions in AM due to the combination of fused/bound and bare powder regions. As compared to counter-rotation, the proposed rotational oscillation kinematics are particularly attractive because they can overcome practical issues with mechanical runout of roller mechanisms (which limit their precision).

Antibacterial Activitiy of Triterpeniod Compounds

The goal of the study was to ascertain whether particular pathogenic bacteria could be inhibited by triterpeniod substances obtained from Rosmarinus officinalis (rosemary) extracts. The time frame for completing this construction was July 2023–April 2024. At the beginning, 100 specimens were taken from patients who were undergoing treatment at the Burn Cure Center in Nineveh Governorate, Iraq Routine biochemical testing were used to determine burn infections caused by bacteria, and the Vitek2 compact system was used to confirm the diagnosis. Acinetobacter baumani and Pseudomonas auroginosa were the most common isolates. In order to extract the substance, rosemary (R. officinalis) leaves were air-dried in the shade and then processed into a fine powder using a grinding machine. A soxhlet device was used to extract 50 g of powdered leaves for six hours at 40–60 °C using 250 ml of 75% petroleum ether. Afterwards, the mixture was dried out at 40°C in a rotating evaporator. After being weighed, the extract residue was stored until needed. Using gas chromatography/mass spectrometry (GC/MS), the crude extract was examined. Ursolic acid (1.38), oleanolic acid (3.27), and other triterpeniod substances with varying ratios were identified by GC-MS analysis. The antibacterial activity of triterpeniod compounds was assessed at concentrations of 12.5%, 25%, 50%, and 100% using the well-diffusion Kirby-Bauer method. The test was evaluated in comparison to six bacterial strains. The results indicated that staphylococcus aureus (50%:22mm – 100%: 26mm), staphylococcus haemolyticus (100%: 17mm), and Acinetobacter baumani (50%:18mm – 100%: 22mm) had the highest inhibitory.

Fabrication of 3D printed hydroxyapatite/polymeric bone scaffold

ABSTRACT Reconstruction in cases of osteoporosis or accidents often requires the use of synthetic bones or scaffolds, with hydroxyapatite standing out as a preferred material due to its biocompatibility. This study focuses on the production and characterization of hydroxyapatite-coated 3D-printed bone scaffolds. The 3D-printed structures were fabricated by blending hydroxyapatite powder, synthesized through the solution combustion technique, with a liquid photopolymer, followed by exposure to UV irradiation. The resulting hydroxyapatite/photopolymer scaffolds were characterized by a uniform distribution of fine hydroxyapatite powder on the surface. Subsequently, these scaffolds underwent coating with a hydroxyapatite slurry, experimenting with various coating and sintering conditions. Despite the decomposition of the photopolymer during the sintering process, the coated scaffold displayed an increased thickness of the infill line within the pattern, resulting in reduced void size and enhanced compressive strength. Weibull analysis of the compressive strength indicated a high likelihood of survival at 4 MPa, falling within the acceptable range for cancellous bone strength. This comprehensive study showcased the potential of hydroxyapatite-coated 3D-printed bone scaffolds with a favorable microstructure and mechanical strength, making them promising for applications in bone reconstruction.

Effect of recycled fine powder as a calcium source on fresh and hardened properties of geopolymer mortar

This study explores the efficacy of Recycled Fine Powder (RFP) derived from construction and demolition waste as a sustainable substitute for Ordinary Portland Cement (OPC) as a Calcium (Ca) source in geopolymer mortar. Fresh properties of Geopolymer Mortar (GPM) were evaluated in terms of slump-flow, initial-final setting time, whereas hardened properties were evaluated in terms of Compressive Strength (CS), Water Absorption (WA), porosity, acid attack, and dry shrinkage at both ambient and heat curing. Results indicate that the RFP performs well in all mixes. However, mix C10R10 shows the overall best results, as 17% higher compressive strength was observed as compared to mix C20R0, which further increases to 88% when compared to mix C0R0. Thus, RFP provides sufficient Ca content as an activator in GPM.

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene as an Environmentally Friendly Modifier for Polyurethane Powder Coatings with Increased Thermal Stability and Corrosion Resistance.

Protection against fire and the corrosion of metals is necessary to ensure human safety. Most of the fire and corrosion inhibitors do not meet the ecological requirements. Therefore, effective and ecological methods of protecting metals are currently a challenge for researchers. In this work, the influence of hexakis(4-(hydroxymethyl)phenoxy)cyclotriphosphazene (HHPCP) on the characteristics of powder coatings was examined. The coatings' properties were investigated by measuring the roughness, hardness, adhesion to the steel surface, cupping, gloss, scratch resistance, and water contact angle. The thermal stability was studied by furnace test and TGA analysis. The corrosion resistance test was carried out in a 3.5% NaCl solution. The distribution of phosphazene-derived segments in the coating was examined by GD-EOS analysis. Modified coatings show better corrosion and thermal resistance and can be used for the protection of the steel surface. Their better corrosion resistance is due to the electroactive properties of the phosphazene ring and its higher concentration at the coating surface, confirmed by GD-EOS analysis. The increase in thermal resistance is due to the effect of the formation of phosphoric metaphosphoric and polyphosphoric acids during the decomposition of HHCPC, which remain in the condensed char phase and play a crucial role in surface protection.

Effects of superfine grinding Tremella fuciformis stem on the texture and quality of dough for steamed bun

Tremella fuciformis (TF) stem accounts for about 10% of the whole mushroom, and most of them are dumped without utilization. To effectively utilize the waste, the effects of fine grinding and superfine grinding technology on the processing characteristics and physicochemical properties of Tremella fuciformis stem powder (TFSP) were investigated, and the effects of TFSP on the quality of steamed bun were analyzed. The findings indicate that the specific surface area of superfine Tremella fuciformis stem powder (STFSP) is 1.6 times larger than that of fine Tremella fuciformis stem powder (FTFSP). Despite this, the infrared spectra of STFSP and FTFSP are similar. The water solubility index and oil holding capacities of STFSP saw an increase of 18.81%, whereas its water holding capacity decreased by 11.34%. Superfine grinding not only enhanced the processing characteristics but also stabilized the powder form. Moreover, steamed buns incorporating 4% STFSP were judged to have the optimal taste. Superfine grinding significantly influences the physicochemical properties of TFSP, resulting in enhanced quality of steamed buns.

Structural Modification of Fine Powders of Overburden Rocks of Saponite-Containing Bentonite Clay

Structural Modification of Fine Powders of Overburden Rocks of Saponite-Containing Bentonite Clay

Development of Dry Fruits Laddoo

Abstract: The aim is to prepare Balls (ladoo) as a nutritional point of view and to provide convenience to the consumer. The ingredient which was used for preparation of balls is Dates (Phoenix dactylifera) which contains Energy: 282 cal, Protein: 2.5 g. Carbohydrates: 75 g, Fat: 0.4 g etc. Vitamin B-6 (PYRIDOXINE) is present. Minerals such as Calcium, iron, Magnesium are present in Dates. The flax seeds are very important in regular diet for humans especially for females. They increase nutrient absorption, help in weight loss, gluten free, rich in antioxidants and omega 3 fatty acids. Owing to these health benefits, dietitians and doctors advise to take flax seeds every day. Balls (ladoo) are good and typically made from various flours and dry fruits by various ways. Balls (ladoo) are usually round, sweet, small or large in size. For preparation of Balls (ladoo) ingredients used are pitted dates,flax seeds, almonds, cashews, Jaggery syrup, oats etc. all these ingredients were finely grounded. The formulation was made by varying levels of ingredients. For preparation of Balls (ladoo) all ingredients were roasted and then grounded into fine powder. The dates were pitted and then grounded in mixer grinder. All these grounded ingredients were made into dough by adding Jaggerysyrup. Three trials have been done T1, T2, and T3 by varying proportion of all ingredients and T3 has been selected. Proximate composition of ladoo ware fat content was found out to be 7.08 ± 0.02%, the protein content is 7.85 +0.09 %, the total carbs are 58.40 ± 0.07 %, the energy in ladoo was 328.72 kcal and ash content is about 2.01 ± 0.11% respectively). It was concluded that the Balls (ladoo) can be store for one month in High density polyethylene pouches at room temperature. These balls are rich source of iron so they satisfy consumer’s needs.

Beneficent impact of mixed molecular magnet/neodymium powder for facilitating ethanol dehydration in the pervaporation process

The focus of the study concerned the application of alginate membranes enriched with a mixture of Magnequench Fine Powder (MQFP) and a Molecular Magnet [Fe4(acac)6(Br-mp)2] (MM) in different proportions to improve ethanol dehydration via pervaporation. The paper concentrated on how the combined fillers affected the membranes ability to transport the ethanol/water solution components. It was observed that the integration of MM into MQFP not only improved the magnetic properties but also provided a uniform distribution of the filler in the alginate matrix. By merging the properties of two different fillers, we achieved membranes with outstanding separation process performance. This efficiency was unattainable using each filler separately, highlighting the synergistic effect of combining the two fillers. The membrane with 1 wt% MQFP and 9 wt% MM proved to be the most efficient, with the highest Pervaporation Separation Index and separation factor, reaching 40974 kg⋅m−2⋅h−1 and 12735.14, respectively.

Modeling on rapid prediction and cause diagnosis of boiler combustion efficiency

Presently, a method for determining pulverized coal burnout rate (PCBR) was developed on kinetics combustion model. Proposed method can promptly track influence of air coal ratio (ACR), boiler load, uniformity index (UI), coal powder fineness (CPF), particle size, and air powder mixing uniformity (PMUC) on PCBR. Moreover, developed method with fewer computations, time-saving, simplicity and low-cost can be exploited to diagnose decreasing causation of combustion efficiency.Results indicate, for anthracite and lean coal, ACR should be maintained near optimal value with 9.39–11.59 kg/kg to achieve consummate combustion efficiency. Correspondingly, higher and appropriate ACR with 10.87–12.0 kg/kg and 7.18–7.94 kg/kg should be maintained for bituminous coal and lignite. 0.1 UI improving achieves 0.18 % upgrading in PCBR. PCBR is more sensitive to UI variation above 75 % BMCR. More significant effect is presented for lean coal and lignite with changing PMUC especially below 50 % BMCR. Basically 0.1 PMUC improving achieves 0.55 enhancement in PCBR below 50 % BMCR. Concurrently 0.7 increment is delivered for anthracite and lean coal. Coal with high volatile content causes larger particle sizes of coal powder to burn out at furnace outlet. Investigation result can predict potential financial savings from unburnt carbon (UC) reduction.

Hybrid Alloyed Sinter Hardening Steels Based on Different Prealloyed Powders

Abstract Sinter hardening grade steels were prepared using hybrid alloying by combining Cr-Mo and Mo prealloyed powders with fine Mn-Si masteralloy powders. Compacts from both base powders showed the “internal getter” effect, which however was much more pronounced for the Cr-Mo powders because of the markedly high starting oxygen content. Combining the base powders with the masteralloy resulted in the desired sinter hardenability, the Mo prealloyed powder resulting in somewhat better properties because of more complete dissolution of the masteralloy and lower residual oxygen content.

Ultrasound-Assisted Extraction, Characterization and Assessment of Vegetable Tannins from Guava (Psidium guajava) Leaves for Leather Tanning

For commercial leather processing, chrome tanning is the most used approach but it significantly contributes to environmental pollution. Vegetable tannins, which are large polyphenolic compounds, form strong interactions with proteins and carbohydrates, thereby enhancing the adaptability and value of vegetable-tanned leather as well as reducing environmental impact. In this study, vegetable tannins were extracted from the leaves of Guava plants (Psidium guajava) using ethanol as the solvent, facilitated by ultrasound. Extracted tannins were quantified using the Folin–Ciocâlteu reagent with ultraviolet-visible spectroscopic method. Ultrasound enhanced the extraction process producing a high yield in less time due to its mechanical, thermal, and cavitation impacts. The extracted tannins were characterized by a variety of spectroscopic techniques, including Proton (1H) Nuclear magnetic resonance, Fourier-transform infrared, and ultraviolet-visible spectroscopy. The effect of various process variables, such as temperature, solid-liquid ratio, ultrasonic power, extraction period, and powder fineness, were also investigated to optimize the extraction process. Finally, the extracted tannins were employed in leather tanning processes to assess their potential as tanning agents. The extracted tannins ensured uniform diffusion of tannins, improved thermal stability and reduced the number of tannins in effluent by 68% making it an environmentally friendly leather tanning process.