Particle Breakdown Research Articles

Enhanced thermal stability in additive friction stir deposited ODS IN9052 Al alloy

Mechanically alloyed (MA) oxide dispersion strengthened (ODS) IN9052 Al alloy exhibits excellent strength both at ambient and high temperatures (up to 300 °C). The limited ductility at ambient temperatures, stemming primarily from the inherent microstructure, impede its practical appeal in structural applications. The present study signifies a maiden effort to additively manufacture MA-ODS IN9052 alloy using solid-state additive friction stir deposition (AFSD) process which has added advantages of uniform particle dispersion, severe particle breakdown, and a recrystallized microstructure. This study indicates a remarkable transition from the initial strain softening behavior in the as received alloy to significant work hardening in the AFSD condition, while maintaining satisfactory yield strength of ∼380 MPa at ambient temperature highlighting a favorable strength-ductility synergy. Importantly, exceptional thermal stability has been achieved in the AFSD alloy by systematically optimizing the process parameters to engineer microstructural heterogeneity. The AFSD alloy demonstrated an impressive high temperature strength, with ∼22 % and ∼49 % increase in yield strength as compared to forged alloy at 240 °C and 340 °C, respectively. Enhancing high temperature strength in aluminum alloys has been a long standing goal and the current results outperform other commercially available high temperature Al alloys. Excellent thermal stability in the AFSD processed alloy is attributed to the nano-scale carbon-rich cluster formation around oxides and carbides in the matrix. These particles restrict grain boundary sliding and are more effective in dislocation-particle interaction. The findings are supported by detailed TEM and atom probe tomography analysis.

SolidStir technology: A novel solid-state integrated manufacturing process for structural fabrication

Present study introduces SolidStir® as an integrated solid-state manufacturing technique for extrusion of rods, wires, tubes, and metal-matrix composites with an additional additive manufacturing (AM) capability. The technology has the advantage of using plug-and-play components to enable multiple end products. The extrudates benefit from an equiaxed, and refined microstructure (∼15 µm). AM of Al-15Ce-3Zr alloy showed severe particle breakdown and exhibited better mechanical properties (∼27 % and ∼900 % increase in strength and ductility) compared to the as-cast counterpart. Leveraging the advantages of solid-state manufacturing, this work establishes SolidStir® as a unique solution for modular manufacturing far and beyond the frontiers of earth.

Toward the production of biopolyethylene‐based ecocomposites with improved performance: The potential of eggshell particles as an ecological additive

AbstractLow‐density biopolyethylene (BioLDPE) ecocomposites added with particles of eggshell (ES) residue were produced using linear low‐density polyethylene grafted with maleic anhydride (LDPE‐g‐MA) as a compatibilizing agent. BioLDPE/ES and BioLDPE/ES/LDPE‐g‐MA compounds were processed in a twin‐screw extruder, and the specimens were injection molded. Torque rheometry increased and melt flow index reduced more prominently for the BioLDPE/LDPE‐g‐MA biocomposite with 20 phr ES, suggesting higher viscosity. Consequently, there was a higher level of ES particles breakdown, generating greater distribution and dispersion, as verified in optical microscopy and scanning electron microscopy images. This finding was supported by Fourier transform infrared spectroscopy, considering the intense absorption band at 871 cm−1 for BioLDPE/ES (20 phr)/LDPE‐g‐MA biocomposite, indicating a higher level of ES particles dispersion in BioLDPE matrix. Therefore, BioLDPE/ES (20 phr)/LDPE‐g‐MA biocomposite increased the elastic modulus, tensile strength, Shore D hardness, and heat deflection temperature by 51.4%, 16.9%, 16.4%, and 14, 6%, respectively, related to BioLDPE. Additionally, the flexibility was kept as seen in the elongation at break and impact strength, including not fractured during the impact test. Reported results for the biocomposites are valuable mainly for the polymer additive sector, since the ES has the potential to improve BioLDPE properties, expanding the range of applications.

Structural and electrophysical properties of nanoporous carbon materials obtained from apricot pits

The dependencies of the electrophysical characteristics of nanoporous carbon material (NCM) on the compaction degree of its particles have been investigated in the presented study. It has been found that the maximum value of the electrical conductivity is achieved at a pressure of 2.5 MPa. Furthermore, it has been revealed that the formation of O-compounds on the surface of the studied materials leads to a decrease in electrical conductivity. The correlation between structural-adsorption and electrical-conductive properties of NCMs has been established. Moreover, it has been demonstrated that an increase in the amount of potassium hydroxide results in a decrease in electrical conductivity due to the breakdown of small carbon particles and an increase in contact resistance, while the specific surface area enlarges due to the development of porosity and an increase in the total pore volume.

Effects of destruction of Euglena gracilis by ultrasonic cavitation

Euglena gracilis has attracted attention because it contains the polysaccharide paramylon. In this study, we aimed to destruct E. gracilis by applying ultrasonic cavitation and to elucidate the mechanism. We also examined the breakdown of paramylon particles and attempted to extract paramylon nanofibers. It was suggested that the damage caused by ultrasonic waves was frequency dependent and influenced by the size ratio of the cell to cavitation bubbles, yield strength, and inhibition of cavitation bubble growth in suspension. It is also assumed that the cell destruction rate decreased because it was also dependent on the initial cell density, and an increase in the initial cell density resulted in a decrease in acoustic pressure. The fracture strength of the paramylon particles was much greater than the microjet stress at the acoustic power used in this study, and the paramylon particles did not fracture.

Sustainable microcrystalline cellulose extracted from biowaste Albezia lebeck L. leaves: Biomass exfoliation and physicochemical characterization.

There is a focus on sustainability when manufacturing materials. Utilizing biobased materials and replacing fossil-based products is the main research focus. Bio-composite materials are applied to packaging, filler coatings, and pharmaceuticals. Here, we used the leaves of the agro-waste plant Albizia lebeck L. to extract cellulose. Chemical treatment causing strong acid hydrolysis successfully extracted the cellulose content from the leaves. The cellulose obtained was then strengthened with polylactic acid to make a biobased film for future applications. Fourier transform spectroscopy, scanning electron microscopy, thermal analysis, particle size analysis, visible UV and elemental analysis were all used to characterize the extracted cellulose. SEM and mechanical property analysis were used to check and describe the quality of the reinforced biofilm. The greatest cellulose yield from this raw material was 50.2%. The crystallinity index and crystallite size (CI 70.3% and CS 11.29 nm) were high in the extracted cellulose. The TG (DTG) curve analysis derivative revealed cellulose particle breakdown was initiated around 305.2°C and can endure temperatures up to 600°C. Biofilms reinforced with polylactic acid cellulose (1, 2, 3, and 5% by weight %) exhibited a smooth and parallel surface. As the filler concentration increased, minor agglomeration occurred. The tensile strength of pure polylactic acid (PLA) (34.72 MPa) was extended up to 38.91 MPa for 5% filler. Similarly, Young's modulus also increased to 5.24 MPa. However, the elongation break decreases with the increase of filler content, and the least value of decrease is 7.5 MPa. Concerning prospective implementations, it is expected that the biobased film and cellulose particles will prove to be more functional.

Current rate flash sintering of nickel at ambient temperature in <1 min

AbstractWe show that powder pressed specimens of nickel can be sintered to 99.96% density by injecting electrical current, without the use of a furnace. Full sintering could be accomplished in 10 to 52 s by changing the current rate from 5 to 1 A/s. In all instances, the samples sintered abruptly at a current density of ∼20 A mm−2. The grain size of the sintered samples was somewhat larger than the nickel powder particle size (∼60 μm vs. 40 μm). Tensile testing yielded a yield strength of 98 MPa, ultimate tensile stress of 323 MPa, and ductility of ∼17%. Four in‐operando measurements are reported: (i) sintering, (ii) the change in resistance with current density, (iii) the temperature, and (iv) electroluminescence. The change in resistance during flash sintering exhibited a high peak followed by a steep decline in resistance; the transient is attributed to the breakdown of particle–particle interface resistance. The same cycle repeated with the flash‐sintered, dense sample, did not show the spike, and gave reproducible results. The resistance data for these latter cycles, when viewed as a function of temperature exhibited sigmoidal behavior: initially lower, and then higher than the literature values. This unusual behavior reflects the influence of defects generated during flash. We have also measured the endothermic enthalpy, expressed by the difference between the in situ input electrical energy and the radiation, convection, and specific heat losses. Dividing by the formation energy of Frenkel pairs yields the concentration of defects, estimated to be 0.3–0.4 mol %. These concentrations are far above thermal equilibrium; it is concluded that flash of metals is a far from equilibrium phenomenon.

Enhancing the Techno-Functional Properties of Lentil Protein Isolate Dispersions Using In-Line High-Shear Rotor-Stator Mixing.

In response to global challenges such as climate change and food insecurity, plant proteins have gained interest. Among these, lentils have emerged as a promising source of proteins due to their good nutritional profile and sustainability considerations. However, their widespread use in food products has been impeded by limited solubility. This study aimed to investigate the potential of high-shear mixing, a resource-efficient technique, to enhance lentil protein solubility and its functional properties. Red lentil protein isolate powders were rehydrated and subjected to a semi-continuous in-line high-shear treatment at 10,200 rpm for a timespan ranging from 0 to 15 min. The results highlighted a significant (p < 0.05) increase in solubility from 46.87 to 68.42% after 15 min of shearing and a reduction in particle size as a result of the intense shearing and disruption provided by the rotor and forced passage through the perforations of the stator. The volume-weighted mean diameter decreased from 5.13 to 1.72 µm after 15 min of shearing, also highlighted by the confocal micrographs which confirmed the breakdown of larger particles into smaller and more uniform particles. Rheological analysis indicated consistent Newtonian behaviour across all dispersions, with apparent viscosities ranging from 1.69 to 1.78 mPa.s. Surface hydrophobicity increased significantly (p < 0.05), from 830 to 1245, indicating exposure of otherwise buried hydrophobic groups. Furthermore, colloidal stability of the dispersion was improved, with separation rates decreasing from 71.23 to 24.16%·h-1. The significant enhancements in solubility, particle size reduction, and colloidal stability, highlight the potential of in-line high-shear mixing in improving the functional properties of lentil protein isolates for formulating sustainable food products with enhanced techno-functional properties.

Morphological and Spectral Characterization of Lunar Regolith Breakdown due to Water Ice

Remote sensing observations of the Moon suggest that the lunar polar regolith environment is affected by several natural processes that may cause the regolith in these regions to become more porous and fine particulate. One of these processes may be the mechanical breakdown of regolith particles through the interaction of water ice and regolith by frost wedging. We present morphological and spectral analyses of high-fidelity lunar regolith simulants LHS-1 (lunar highlands simulant-1) and LMS-1 (lunar mare simulant-1) that have been exposed to varying concentrations of water ice (1, 10, and 30 wt%) over extended periods of time (1, 3, and 6 months) to evaluate the extent at which lunar regolith may be weathered by ice-regolith interactions in the Moon’s polar regions. To characterize changes in regolith particle morphology, we explored grain size and shape parameters with the CILAS ExpertShape suite and characterized the abundance and evolution of clinging fines with scanning electron microscopy and energy dispersive X-ray spectroscopy. Reflectance spectra were taken from 1.0–22.5 μm (444.4–10,000 cm−1) to characterize any differences in spectral features that may occur as a result of regolith breakdown. Both the morphological and spectral investigations display trends that show simulant particle degradation as a function of composition, increasing water concentration, and freezing time. Our study demonstrates that the lunar regolith is susceptible to mechanical breakdown in the presence of water ice and that water ice is likely a contributor to the weathering environment within permanently shadowed regions on the lunar surface.

Theoretical study of the process of grain materials grinding in agriculture machinery

This paper outlines the findings of theoretical investigations into the grain materials grinding process in agriculture, focusing on the particle breakdown occurring at the moving edge of the rotor groove relative to the fixed edge of the stator. The choice of grinding methods is influenced by the processed feed, its intended purpose, the adopted feed preparation technology, and the specific farm animals involved. The study highlights the significant variations in the grinding process due to differences in dimensional characteristics and strength properties of grain materials, which impact the selection of working chamber parameters and operating modes. The paper introduces a hexagonal rotary crusher design and technological scheme, which offers the flexibility to adjust the amplitude-frequency characteristics of the working elements, energy of the process, and grinding quality within a wide range. Further research on the system dynamics requires experimental studies of grain material grinders utilizing diverse destruction methods. This study aims to advance understanding of the grain materials grinding process and optimize feed processing techniques for improved livestock productivity and product quality.

Review on impacts of micro- and nano-plastic on aquatic ecosystems and mitigation strategies

The rapid proliferation of microplastics (MPs) and nanoplastics (NPs) in our environment presents a formidable hazard to both biotic and abiotic components. These pollutants originate from various sources, including commercial production and the breakdown of larger plastic particles. Widespread contamination of the human body, agroecosystems, and animals occurs through ingestion, entry into the food chain, and inhalation. Consequently, the imperative to devise innovative methods for MPs and NPs remediation has become increasingly apparent. This review explores the current landscape of strategies proposed to mitigate the escalating threats associated with plastic waste. Among the array of methods in use, microbial remediation emerges as a promising avenue for the decomposition and reclamation of MPs and NPs. In response to the growing concern, numerous nations have already implemented or are in the process of adopting regulations to curtail MPs and NPs in aquatic habitats. This paper aims to address this gap by delving into the environmental fate, behaviour, transport, ecotoxicity, and management of MPs and NPs particles within the context of nanoscience, microbial ecology, and remediation technologies. Key findings of this review encompass the intricate interdependencies between MPs and NPs and their ecosystems. The ecological impact, from fate to ecotoxicity, is scrutinized in light of the burgeoning environmental imperative. As a result, this review not only provides an encompassing understanding of the ecological ramifications of MPs and NPs but also highlights the pressing need for further research, innovation, and informed interventions.

Challenges and optimization of PEMFC system in vehicles

Switching from fossil fuel energy to clean and renewable energy to minimize car emissions is becoming more and more vital and crucial in the current condition of severe environmental pollution and serious fossil fuel shortage. However, there are still several issues with current fuel cell systems that prevent their widespread use. Due to Proton Exchange Membrane Fuel Cells’ (PEMFCs) poor performance and the expensive operating costs of their catalysts, fuel cells are presently not widely accessible on the market. Fuel cells are seen as a potential method to reach the goal of zero emissions since they offer excellent benefits in terms of zero emissions and high efficiency. They do this by converting chemical energy into electrical energy using hydrogen. In this study, the three main parameters that affect the performance of PMFCs and the way in which the fuel cell converts chemical energy into electrical energy are investigated. Carbon corrosion damages PEMFCs performance because of high cathode potential during startup and shutdown. The breakdown of platinum particles employed as catalysts reduces the lifetime of PEMFCs and raises costs. The improvement of fuel cell systems is reviewed, along with methods for gas purification and catalysts produced from various cutting-edge materials including graphitized carbon. In order to address any potential environmental issues with fuel cells and seek to lower greenhouse gas emissions, this paper intends to explore better alternatives and give better remedies for PEMFC performance improvement and cost reduction.

Mechanical Digestion of Broccoli through Chewing and its Impact on Myrosinase Activity

Myrosinase activity on broccoli glucosinolates has been widely and extensively discussed. Purpose: Studies on cruciferous vegetables, especially broccoli, have gained significance in the fight against cancer. Glucosinolates in broccoli transformation into sulforaphane occur after its exposure through chewing. However, the relationship between individual chewing patterns and denture morphology has not been studied extensively. Research on human digestion has demonstrated how the mechanical breakdown of larger food particles into smaller ones is a crucial precursor to chemical food breakdown. This study is a comparative analysis of how chewing on broccoli tissues by different individuals enables the enzyme myrosinase to break down broccoli glucosinolates chemically. We investigate the individual chewing patterns linked to the surface anatomy of the pre-molars and molars and the myrosinase activity on broccoli glucosinolates. Methods: Three individuals chewed a 4-millimeter broccoli floret four times sequentially (2 grams), and we measured the floret length at each bite until the sample was ground. Then, we combined the chewed broccoli with distilled water, filtered it, and myrosinase activity was measured using photo spectrometric measurements and an agar diffusion test. Individual pre-molars and molars samples were measured in millimetres. Results: Data from the three human chewing mechanisms compared to the mechanical breakdown performed by an automatic mixer shows different and individually specific values. Conclusion: Individual chewing patterns link to the unique surface anatomy of the pre-molars and molars, subsequently impacting the myrosinase activity on broccoli glucosinolates’ breakdown individually

Fabrication, physicochemical properties and structural characteristics of nanoparticles from carrot pomace and its insoluble dietary fiber

Modifying insoluble dietary fiber (IDF) to improve its application has received a growing interest in the food industry. In this study, carrot pomace and extracted IDF nanoparticles (CPNPs and IDFNPs, respectively) were produced in the sequence of milling, homogenization, and ultrasonication which resulted in the breakdown of particles and subsequently, the formation of NPs with sizes of ∼200 nm. The results demonstrated that nanosizing treatment effectively pulverized the particle sizes of CP (279 μm–203 nm). As the particle size decreased, ζ-potential (−17.9 to −22.9 mV), WHC (17.1–19.7%), and OHC (3.7–19.3%) tended to increase significantly (p < 0.05), in which, the highest WHC (21.29 g/g), OHC (25.49 g/g), as well as the absolute value of the ζ-potential (−38.8 mV) and the smallest contact angle (23.795°) were detected for IDFNPs. SEM images also revealed an increment in surface porosity after nanosizing process. However, based on XRD analysis, the crystalline structure of particles was not obviously different, which was confirmed by the results of FTIR spectroscopy. The results revealed carrot pomace NPs could be suitable for typical nanoparticle applications, such as Pickering stabilizers, emulsifiers, thickeners, and even fat replacers.

Particle size and water content impact breakdown and starch digestibility of chickpea snacks during in vitro gastrointestinal digestion

Chickpeas are an agriculturally-important legume that are an excellent source of protein, fiber, and minerals. Developing chickpea-based snacks could provide consumers with snack products rich in protein and other nutrients. In this study, chickpea puree (high moisture content) and cracker (low moisture content) were each produced with large (7 mm sieve; coarse) or small (2 mm sieve; fine) particle size to investigate the impact of initial particle size and moisture content on particle breakdown, starch hydrolysis, and protein hydrolysis during in vitro digestion. All treatments underwent static in vitro oral digestion, dynamic gastric digestion in the Human Gastric Simulator (HGS), and static in vitro small intestinal digestion. The emptying rate from the HGS was significantly (p < 0.05) higher for fine puree compared to the other treatments, due to higher saturation ratio and smaller initial particle size. The reducing sugars and free amino groups released (representing starch and protein hydrolysis, respectively) from fine puree were higher than coarse puree, and fine cracker was higher than coarse cracker due to the influence of initial particle size. For example, after 360 min total in vitro digestion, the starch hydrolysis of the fine cracker (48.1 ± 3.2%) was significantly higher than (p < 0.05) the coarse cracker (36.3 ± 5.8%). Overall, crackers had higher protein and starch hydrolysis compared to puree in the liquid phase during digestion. The study showed that both the smaller initial particle size and drying significantly (p < 0.05) increased the particle size reduction during gastric digestion and starch and protein digestibility in chickpea-based snacks.

Characterization of microplastics and its pollution load index in freshwater Kumaraswamy Lake of Coimbatore, India

Microplastics are less than 5 mm in diameter that enters the ecosystem through the breakdown of large plastic particles or climate and human activity. This study examined the geographical and seasonal distribution of microplastics in the surface water of Kumaraswamy Lake, Coimbatore. During seasons, including summer, pre-monsoon, monsoon, and post-monsoon, samples were collected from the lake's inlet, centre, and outlet. All sampling points contained linear low-density polyethylene, high-density polyethylene, polyethylene terephthalate, and polypropylene microplastics. Water samples contained fibre, thin, fragment, and film microplastics in black, pink, blue, white, transparent, and yellow colours. Lake's microplastic pollution load index was under 10, indicating risk I. Over four seasons, microplastic content was 8.77 ± 0.27 particles per litre. The monsoon season had the highest microplastic concentration, followed by pre-monsoon, post-monsoon, and summer. These findings imply that the spatial and seasonal distribution of microplastics may be harmful to the fauna and flora of the lake.

Effect of Fat to Lean Meat Ratios on the Formation of Volatile Compounds in Mutton Shashliks.

This study aimed to investigate the release of volatile compounds in mutton shashliks (named as FxLy, x-fat cubes: 0-4; y-lean cubes: 4-0) with different fat-lean ratios before and during consumption, respectively. In total, 67 volatile compounds were identified in shashliks using gas chromatography/mass spectrometry. Aldehyde, alcohol, and ketone were the major volatile substances, accounting for more than 75% of the total volatile compounds. There were significant differences in the volatile compounds of mutton shashliks with different fat-lean ratios. With the increase of the fat content, the types and content of volatile substances released also increase. However, when the percentage of fat exceeded 50%, the number of furans and pyrazine, which were characteristic of the volatile compounds of roasted meat, was decreased. The release of volatiles during the consumption of mutton shashliks was measured using the exhaled breath test and the results showed that adding an appropriate amount of fat (<50%) helps to enrich the volatile compound components in the mouth. However, shashliks with higher fat-lean ratios (>2:2) shorten the mastication duration and weaken the breakdown of bolus particles in the consumption process, which is not conducive to the release potential of volatile substances. Therefore, setting the fat to lean ratio to 2:2 is the best choice for making mutton shashliks, as it (F2L2) can provide rich flavor substances for mutton shashliks before and during consumption.

Fe-SiC-Sn-Mn reinforced surface composite via FSP: A comprehensive analysis

This investigation reports a maiden work on the fabrication of surface composite through hybrid reinforcement powders by adding Fe, Mn, and Sn metallic powders to ceramics (SiC) in aluminum AA5083 alloy matrix via friction stir processing. Stitched micrographs were employed to demonstrate the variation in grain size distribution from the stir zone (10 µm) to the base metal (52.68 µm) during the processing. With the aid of scanning electron microscopy, energy dispersive spectroscopy, area mapping and X-ray diffraction analysis, it has been determined how reinforcement was distributed and what phases evolved in the stir zone. Tensile test was performed to evaluate the strength of the fabricated composite and micro-hardness maps indicated a 54.4 % increase in hardness after processing.The observed enhancement is attributed to the Hall-Petch and pinning effect. A potentiodynamic polarization test was carried out to study the corrosion behavior and it was ascertained that corrosion resistance of the processed sample got enhanced because of grain refinement, formation of galvanic couple and breakdown of second phase particles owing to intense stirring.

Experimental Study of the Dynamic Mechanical Behavior and Degradation Mechanism of Red Sandstone in Acid Dry-Wet Cycles

In this paper, the slit Hopkinson pressure bar (SHPB) experiments were conducted to investigate the dynamic mechanical characteristics of red sandstone during acid dry-wet cycles. The appearance of the samples was evaluated using scanning electron microscopy, and the process of red sandstone degradation under acid dry-wet cycles was examined. The results reveal that, as compared to neutral solution, acid solution enhances the degree of degradation induced by dry-wet cycles in red sandstone. The dynamic compressive strength and elastic modulus of red sandstone steadily decline as the number of dry-wet cycles increases, and the lower the pH of solution, the greater the reduction. The mechanism of degradation of red sandstone during acid dry-wet cycles may be explained in two ways. First, the chemical interaction between the mineral components in the sample, such as cement and feldspar, and H+ in the acid solution has accelerated the formation of secondary pores and fractures, resulting in a decrease in the cementation capacity between mineral particles. Second, partial breakdown of the major mineral particles softens the mineral skeleton.

Attributes of intergranular corrosion in AA6061-AA7075 double sided friction stir weld

The present study aims to observe the distinguishable progression of intergranular corrosion (IGC) in dissimilar AA6061-AA7075 double-sided friction stir welds (DSFSW) with and without employing secondary heating. Transverse weld specimen sectioned along the weld line, to separate advancing and retreating side, are electrochemically corroded. Secondary heating helps in impeding the most accelerated corrosion rate dominated over the AA7075 region by approximately 50%. The double stirred region remains least susceptible to corrosion due to the dissolution and break down of precipitates. The degree of homogenization during stirring of dissimilar alloy controls the degree of material depletion during corrosion, making intercalated structure unfavourable in terms of corrosion. IGC is found more aggressive in AA7075 structurally intercalated with AA6061 in stir zone. The coarse grain, wider precipitate free zones and continuity of the precipitates along grain boundary (GB) are interpreted as most influential factors. Additional/secondary heating resulted into retardation of IGC within the AA7075 but resulted continuous IGC along the GBs of AA6061. Low angle GBs appears more resistive against IGC as they allow the formation of lean precipitates on contrary to high angle GBs. Secondary heating boosts breakdown and dissolution of corrosion sensitive secondary phase particles reducing the intergranular corrosion tendency.