Impact Mill Research Articles

Effect of Joining Mechanism on the Mechanical Recycling of Polymer–Metal Composite Parts

In order to be able to recycle composite components made of polymer and metal, which are used in the automotive industry, the joints must be broken. The success of the separation is influenced by the stress and also by the joining mechanism between the polymer and the metal. Here, force-fit and form-fit connected components are produced and crushed in a rotor impact mill with two different rotors. The results show that the crushing results differ significantly for the different rotors and for the various joining processes. In short, the hammer-type rotor provides much finer and better-separated fragments and the force-fit joints enable a better separation of metal and polymers. The additional cooling of the samples also changes the result in a way, where deep cooling significantly improves the separation of the metal and the polymer. Different types of polymers also led to a different separation result with both rotors.

Unravelling the bread-making functionality of gluten-rich sub-aleurone flour obtained by dry fractionation of wheat miller’s bran

The residual endosperm of wheat miller’s bran is rich in gluten proteins due to the presence of protein-rich sub-aleurone cells. Here, the goal was to gain insight into the bread-making functionality of sub-aleurone gluten-enriched fractions obtained through dry fractionation of miller’s bran and the inherent bread-making functionality of sub-aleurone gluten. Therefore, two sub-aleurone gluten-enriched fractions (Sub-alF and Sub-alC), differing in particle size distribution and chemical composition, were prepared from miller’s bran using impact milling, sieving, and air classification. Substituting 22.5 % of white flour with Sub-alF, Sub-alC, commercial gluten A (GluA) and B (GluB), all standardised to a protein content of 20.6 % with wheat starch, led to an increase in specific loaf volume of 14.8 %, 14.0 %, 14.3 %, and 21.8 %, respectively. Despite their higher level of bran contamination and lower relative gluten content, Sub-alF and Sub-alC were equally functional as commercial gluten (GluA). This could be due to wet fractionation, which is used in commercial gluten production, reducing the functionality of gluten, as indicated by comparing the functionality of gluten in Sub-alC and gluten isolated via wet fractionation from Sub-alC with GluA. Substituting 6 % of white flour with gluten isolated via wet fractionation from Sub-alC and from the corresponding flour increased the specific volume by 27.2 % and 29.4 %, respectively. Sub-aleurone gluten and flour gluten were, hence, functionally comparable. In conclusion, the sub-aleurone’s high content of functional gluten enables the production of functional gluten-enriched ingredients from miller’s bran.

Impact Mill

An impact mill has been developed to produce powders from shavings of refractory metals using impact grinding method for reuse in electrometallurgy in devices with screw feed, for example, in 3D printers. The proposed device provides high uniformity of grinding with a minimum content of dust fraction and impurity content at low technical and economic costs. The result is achieved by using a Laval nozzle, which operates in the supersonic jet formation mode. In the area of the first Mach disk there are rod fenders arranged in a cascade, and the impact plate is located in the turbulence zone and is equipped with winglets with holes for separating crushed metal.

Modification of cement-based circulating fluidized bed combustion slag: Physical grinding and chemical excitation

This study investigates the effects of physical grinding (ball, impact, and jet milling) and chemical modification (using various dosages of Na2SO4, CaO, triethanolamine (TEA), and their composite modifiers) on CFBCS. The fluidity, flexural strength, compressive strength, and expansion rate of different modification methods were tested. Microstructural and phase composition analyses were conducted using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, mercury intrusion porosimetry, and thermogravimetry-differential thermogravimetry. The results indicated that impact milling improved mortar fluidity by 2.9 % compared to ball milling, while jet milling reduced it by 5.7 %. Chemical modifications decreased paste fluidity but increased mortar strength and reduced expansion rates. Impact milling and jet milling improved 28-day compressive strength by 13.76 % and 16.01 %, respectively, and reduced the 90-day expansion rate by 0.007 % and 0.012 %, respectively. Composite chemical modification (CM-C) enhanced 28-day compressive strength by 23.88 % and reduced the 90-day expansion rate by 0.019 %. Microscopic analysis shows that modification reduced the pores and pore size of the mortar while increasing the hydration products. After TEA modification, rod-shaped AFt forms a reticulated structure, with C–S–H gel and CH crystals adhering to it. The hydration products of CFBCS mortar formed a network after jet milling, and the addition of composite modifiers resulted in a layered, dense structure.

Influence of Dry-Mixing and Solvent Casting Blending Techniques on the Mechanical and Biological Behavior of Novel Biocompatible Poly(ε-caprolactone)/Alumina-Toughened Zirconia Scaffolds Obtained by 3D Printing

This work focuses on the study and comparison of two mixing methods for the dispersion of Alumina-Toughened Zirconia (ATZ) within the polymer matrix of Poly(ε-caprolactone) (PCL). The dry-mixing method using solvent-free impact milling (M) and the solvent casting method with chloroform (SC) were investigated. Samples were produced by 3D printing, and specimens were printed at increasing ATZ loadings (namely, 10, 20, and 40 wt.%). The chemico-physical, mechanical, and cell interaction characteristics of the materials prepared with both mixing methods were studied. Solvent mixing allowed better dispersion of the ATZ in the polymer matrix with respect to dry mixing. In addition, dry mixing affected the molecular weight of the PCL/ATZ composites much more than the solvent casting method. For these reasons, materials obtained by solid mixing exhibited the worst mechanical performance with respect to those obtained by solvent casting, which showed increased Young’s moduli with increasing ATZ amounts. The in vitro biological response elicited in a mesenchymal stem cell model seemed to be influenced by the mixing method, with a preference for the composites obtained through solvent mixing and containing 20 or 40 wt.% of ATZ.

Early adopter insights on physical impact mill technology for harvest weed seed control in Canada

The evolution and spread of herbicide resistance among the weed community has increased interest in alternative weed management strategies such as harvest weed seed control. Western Canadian producers have begun adopting physical impact mills as an additional weed management strategy. A survey of early adopters of physical impact mill technology in Canada was conducted to better understand the motivations behind producers adopting, initial experiences, and research needs. Ten producers responded to the survey, accounting for 18 out of an estimated 30 impact mills in use in Canada, believed to be located primarily in the Canadian Prairies. These producers were mainly from larger farms (>4000 ha), equipped the majority of their combines (75% average) and used the mills in essentially all crops grown. The majority of respondents were located in Saskatchewan, with two mills being used in Alberta. Wild oat ( Avena fatua L.) (60%) and kochia ( Bassia scoparia (L.) A.J. Scott) (50%) were the weeds most frequently mentioned as specific motivators of impact mill adoption. Average increased fuel cost from the mill was estimated at CAD$3.46 ha−1, with average annual maintenance costs of about $1500 per impact mill. Producers relied on information from mill companies and other early-adopting farmers primarily, followed by extension talks and social media. Research needs were also identified by producers that could inform the future direction of harvest weed seed control research in Canada. Future research should focus on confirming efficacy, optimizing combine settings, and looking at integrated systems with precision agriculture technologies.

Field testing of a physical impact mill in the Canadian Prairies

Herbicide resistance in western Canada has increased interest in alternative weed management strategies. Physical impact mills, a form of harvest weed seed control, have been identified as a strategy that may be well suited for Canadian use. The efficacy of the Harrington Seed Destructor, a physical impact mill, was evaluated in 20 producer fields in Alberta on a wide spectrum of weed species over 3 years. Significant differences in weed densities between the physical impact mill treatment and the regular harvest densities were few; however, some population density reductions were observed. Measurable reductions in weed densities may have been limited by the short timeframe of the experiment, the high initial densities of the weeds, or the targeted weed species having dormancy or longer term seedbanks. Additionally, identified knowledge gaps on how best to optimize physical impact mill efficacy may have reduced the efficacy of the physical impact mill in this study. This study showed no conclusive evidence for the efficacy of a physical impact mill on tested weed species under field conditions. However, it did provide a number of important considerations for future studies.

Comparing electrostatic separation of soy and lupin: Effect of de-oiling by solvent extraction

Electrostatic separation is a sustainable dry separation technique based on triboelectric charging of different cellular tissue components (i.e. protein bodies and fibres). This research aimed to determine the mechanism behind the ineffective electrostatic separation of soy and if it could be altered by de-oiling. Several scenarios were compared, which involved electrostatic separation of soy and lupin de-oiled with different solvents (none, acetone, ethanol and hexane). Separation of lupin resulted in a higher true protein content (58.5%DM (dry matter) (Nfactor = 5.7)) than separation of soy (45.0%DM protein). Separation was less effective for soy because its protein bodies were still embedded in the cellular structure after impact milling, which was also reflected in the larger particle size and lower small particle dispersibility. De-oiling soy with hexane and extra milling improved the purity of soy protein-enriched fractions (59.6%DM protein) reaching more similar purity as for lupin protein-enriched fractions. The protein purity of lupin fractions could be increased most via the use of polar solvents (acetone and ethanol). Better electrostatic separation after de-oiling and extra milling for soy could be explained by increased liberated protein bodies, which was key towards the improved separation of soy obtaining protein purities closer to that of pure protein bodies.

Sorghum (Sorghum bicolor L. Moench) Gluten-Free Bread: The Effect of Milling Conditions on the Technological Properties and In Vitro Bioaccessibility of Polyphenols and Minerals.

The absence of gluten proteins in sorghum allows for the production of baked goods that are suitable for celiacs. Previous studies have shown that the milling process affects the performance of sorghum flour in baked products, especially those that are gluten-free (GF). This study aimed to explore the effects of mill type (impact and roller) on flour properties and GF bread quality by assessing the technological quality, antioxidant activity, and mineral content of the bread. All particle populations of flour obtained via both millings presented a bimodal distribution, and the volume mean diameter (D 4,3) ranged from 431.6 µm to 561.6 µm. The partially refined milled flour obtained via polishing and impact milling produced bread with a soft crumb, fewer but larger alveoli in the crumb, and a structure that did not collapse during baking, showing the best performance in bread quality. In the in vitro bread digestibility assay, the total polyphenol content and antioxidant activity decreased during the digestion steps. High mineral (Cu, Fe, Mn, and Zn) contents were also found in a portion of the bread (120 g) made with whole sorghum flour; however, their potential bioavailability was reduced in the presence of a higher amount of bran.

Re-visitation of Two Models for Predicting Mechanically-Induced Disordering after Cryogenic Impact Milling.

To compare the prediction accuracy of two models used to characterize the complete disordering potential of materials after extensive cryogenic milling. Elastic shear moduli (μs) were simulated in silico. Comparison with available literature values confirmed that computations were reasonable. Complete disordering potential was predicted using the critical dislocation density (ρcrit) and bivariate empirical models. To compare the prediction accuracy of the models, each material added for dataset expansion was cryomilled for up to 5 hr. Mechanical disordering after comminution was characterized using PXRD and DSC, and pooled with previously published results. Simulated μs enabled predictions using the ρcrit model for 29 materials. This model mischaracterized the complete disordering behavior for 13/29 materials, giving an overall prediction accuracy of 55%. The originally published bivariate empirical model classification boundary correctly grouped the disordering potential for 31/32 materials from the expanded dataset. Recalibration of this model retained a 94% prediction accuracy, with only 2 misclassifications. Prediction accuracy of the ρcrit model decreased with dataset expansion, relative to previously published results. Overall, the ρcrit model was considerably less accurate relative to the bivariate empirical model, which retained very high prediction accuracy for the expanded dataset. Although the empirical model does not imply a mechanism, model robustness suggests the importance of glass transition temperature (Tg) and molar volume (Mv) on formation and persistence of amorphous materials following extensive cryomilling.

An Innovative Absorption Propagation System Hollow Block Made of Concrete Modified with Styrene-Butadiene Rubber and Polyethylene Terephthalate Flakes to Reduce the Propagation of Mechanical Vibrations in Walls.

This paper discusses an innovative APS hollow block wall with a frame made of concrete modified with recycled materials. The technical data of the hollow block, the percentages of the recycled materials, including SBR rubber granules and PET flakes in the modified concrete, and the composition of the concrete modified with this mixture of recycled additives, are presented. To demonstrate the effectiveness of the solution in reducing mechanical vibrations, the effect of the interaction of different frequencies of the mechanical wave on reducing these vibrations was evaluated for APS blocks and Alpha comparison blocks. The test was carried out on a developed test stand dedicated to dynamic measurements for sixteen frequencies in the range from 8 to 5000 Hz, forcing a sinusoidal course of vibrations. The results are presented graphically and show that the new type of APS hollow block wall was much more effective in reducing mechanical vibrations. This efficiency was in the range from 10 to 51% for 12 out of the tested 16 frequencies. For the frequencies of 8, 16, 128, and 2000 Hz, the values were obtained with a difference of 3.58% in favor of the APS hollow block. In addition, the study of the damping effectiveness of the APS hollow blocks, in relation to the vibrations generated by an M-400 impact mill, showed that the APS block wall had a higher damping efficiency of 16.87% compared to the Alpha hollow block for the signal reading on the floor next to the mill, and 18.68% for the signal reading on the mill body. The modified concrete used in the production of the APS hollow blocks enabled the effective use of two recycled materials, SBR rubber and polyethylene terephthalate, in the form of PET flakes.

Study of an Impact Mill-Based Mechanical Method for NdFeB Magnet Recycling

Nowadays, the circular economy is gaining more and more attention in sectors where the raw material supply is critical for both cost and geo-political reasons. Moreover, the environmental impact issue calls for recycling. From this perspective, the recovery of rare earth elements represents a strategic point. On the other hand, the high cost and the dangerous standard recovery methods that apply to NdFeB magnets limits options for traditional recycling. A new mechanical method is proposed, not requiring hydrogen, high temperature, or chemical processes, but instead using an impact mill designed to operate in vacuum. A traditional impact mill operating in a glove box filled with Ar atmosphere has also been used for comparison. The obtained NdFeB powders were analyzed in terms of magnetic properties and chemical composition, particularly in terms of the oxygen content.

Harvest weed seed control in soybean with an impact mill

AbstractThe distribution of herbicide-resistant weeds such as waterhemp has resulted in a greater need for a more integrated approach to weed management, especially in U.S. soybean production systems. Previous research has shown harvest weed seed control (HWSC) to be an effective method of reducing the amount of weed seed returning to the soil. One form of HWSC is the use of impact mills to destroy weed seed exiting the combine during harvest. In 2019 and 2020, we investigated the efficacy and operating costs of the Seed TerminatorTM impact mill in five Missouri soybean fields that contained significant waterhemp infestations. Results indicated that 22% to 40% of the available waterhemp seed in the field at harvest drops to the soil surface because of shatter whenever the combine reel contacts waterhemp plants. Across all locations, an average of 94% of waterhemp seed exiting the Seed Terminator™ was substantially damaged and considered nonviable. Consecutive seasons of use of the Seed TerminatorTM on the same field in two of the locations resulted in a 96% to 97% reduction of waterhemp in the soil seed bank the spring following the second harvest. The estimated increased operating cost of using a Seed Terminator™ was $14.18 ha–1 compared to harvesting with a conventional combine alone. Engine load increased by 12.5%, fuel consumption was 11.3 L h–1 and 1 L ha–1 greater with the Seed Terminator™, but there was no reduction in productivity when harvesting with a combine equipped with a Seed TerminatorTM compared to a conventional combine. The use of impact mills could play a significant role in reducing soil weed seed banks in soybean production systems in at least the Midwest region of the United States in the future.

On Charles Mills’s “Black Radical Kantianism”

In this remembrance essay I reflect on my seventeen years of friendship and apprenticeship with Charles W. Mills. I focus on Mills’s “Black Radical Kantianism,” (2018) situating it in light of his earlier work on Kant, history of philosophy, political philosophy, and race, and demonstrating the lasting impact of Mills’s work especially on Kant Studies and Kantian moral-legal-political philosophy. In this analysis, I both acknowledge Mills’s radicalization of Kantianism as a major win toward making white supremacy visible in Kant Studies and political philosophy and remain skeptical of Mills’s strategy of revising liberalism and especially Kantianism for reparative justice projects. After all, holding multiple and seemingly contradictory truths at once is something I have learned from Charles, as it will become clear.

Structure characteristics and physicochemical property of starch, dietary fiber, protein in purple corn flour modified by low temperature impact mill

The structural changes of macromolecules (starch, dietary fiber and protein) in purple corn flour (PCF) modified by a low temperature impact mill (LTIM) at different air classifier speed (ACS) were investigated. LTIM changed the multi-scale structure of starch, which was characterized by increased starch damage, stronger destruction of relative crystallinity (from 37.85 % to 15.53 %) and short-range ordered structure (R1047/1022, from 1.21 to 0.73) with the increased ACS. The structure of dietary fiber was also destroyed on multi-level, including decreased particle size, destructive morphology, and slightly changed crystalline structure. Additionally, LTIM showed high damage on the senior structure (surface hydrophobicity, disulfide bond, secondary structure) of protein. Due to the structure changes modified by LTIM, starch, dietary fiber and protein played different role on hydration property of PCF. Starch had positive effect, while dietary fiber and protein had negative effect. Our experimental results may provide valuable information for further analysis of other quality changes (oil holding capacity, cation exchange capacity, ability to produce high-quality dough or end-out products, etc.) of purple corn flour after LTIM treatment.

Electrostatic separation of pea proteins assisted by COMSOL simulation

To address the dilemma of inefficient plant protein electrostatic separation, some optimization strategies were proposed by combining experimental analysis with COMSOL Multiphysics simulation. Micronized pea powder was obtained by airflow impact mill. The design of a near-cylindrical buffer zone (diameter 6.2 cm, height 10 cm) above the separation chamber can convert the turbulent flow from the tribo-charging system into laminar, slow down the airflow velocity and weaken propulsion on the particles. Moderate particle charge (464.8 ± 24.9 nC/g) and high electric field strength (2.0 kV/cm) can ensure the required electric field force for separation while reducing inter-particle aggregation. The formation of a steady magnetic field by two neodymium magnets, placed perpendicular to the electric field, was a potentially valuable auxiliary force in the separation of charged particles, but strictly limited by the magnetic field strength. With those improvements, pea protein concentrate purity was increased from 27.8 ± 0.5% (db) to 62.6 ± 0.6% (db) after one-step electrostatic separation. Combined with the visualization of simulation, this study provided a new insight into improving the electrostatic separation efficiency of micronized powder. • Pre-slowing airflow velocity through buffer zone improves separation efficiency. • Particle aggregation due to high charge negatively impacts separation. • Moderate particle charging and high separation voltage is the optimal strategy. • High intensity magnetic field can separate different charged particles exclusively. • Numerical simulation of separation field, airflow and charged particle trajectory.

Steam bread made by superfine purple corn flour: Texture characteristics and in vitro starch digestibility

The performance of purple corn flour (PCF) with various size pulverized by low temperature impact mill (LTIM) in making steamed bread was investigated. Results indicated that decreased diameter of PCF showed richer red with increased a* (4.43–7.34), stronger adhesiveness (0.04–2.25 N s), more appropriate hardness (15.20–48.30 N), lower water fluidity (T2, ranged from 19.05 to 14.12 ms), and more cross-linking structure to purple corn dough (PCD). PCD texture characteristics were significantly affected by starch network and filler-like effect of dietary fiber based on the additional adding dietary fiber to starch. Steamed bread made by finer size PCF (56 μm) exhibited favorable quality supported by smooth skin, regular shape, porous structure, appropriate texture properties and low starch digestibility, which was mainly due to the higher α-amylase inhibitory activity of dietary fiber. These results confirmed that using PCF prepared by LTIM could be a suitable option to get good-quality whole grain food.

Intact aleurone cells limit the hydrolysis of endogenous lipids in wheat bran during storage

This work aimed to elucidate the effect of aleurone cell integrity on the hydrolysis of endogenous lipids in wheat bran and flour. The distribution of lipases in the bran dissected layers (aleurone layer, outer pericarp and intermediate layer) and the lipid hydrolysis in the bran fractions and flour containing the aleurone cells with different integrity were investigated. The results indicated that 80% of the lipase activities in bran layers were associated with the aleurone layer. After centrifugal impact milling, the aleurone layer in commercial bran could be detached into the monolayer cell clusters with decreasing integrities as the particle size decreased. In the oil phase, intact aleurone cells did not limit the lipase activities in the bran fractions because the oil could penetrate into aleurone cells. During storage, the hydrolysis rates of endogenous lipids in the bran fractions and their mixed flour increased as the integrity of aleurone cells decreased; while after the aleurone cells were broken, the hydrolysis rates of endogenous lipids increased to be in line with the lipase activities in bran fractions, indicating the limitation of intact aleurone cells on lipid hydrolysis. These results gave a new understanding of the effect of aleurone cell structure on the interaction between lipases and lipids in wheat bran, and will facilitate the production of stable wheat bran and whole wheat flour.

Raman Spectroscopy and Electron Microscopy Studies of Ga FIB and Post-FIB Ar Ion Milling's Impact on Si TEM Specimens

Raman Spectroscopy and Electron Microscopy Studies of Ga FIB and Post-FIB Ar Ion Milling's Impact on Si TEM Specimens

Effect of tempering conditions and mill type on physicochemical and functional properties of sorghum ( Sorghum bicolor [L.] Moench) flour

The objective of this study was to determine the effect of mill type and moisture content of sorghum (Sorghum bicolor [L.] Moench) grains on the flour yield and the physicochemical and functional properties of flour. Three commercial hybrids of sorghum grains were tempered between 8.2% and 15.5% of water content and milled by both roller and pearling-impact processes. The increase in pearling time decreased the milling yield and the ash content of the flour, reaching values between 47.20–78.02% and 0.44–0.76%, respectively, at 180 s of pearling time. A similar effect was shown in flours produced by roller milling with high moisture content; obtaining values between 47.99–55.82% flour yield, and 0.42–0.64% ash content, at 15.5% moisture content. The pasting viscosity and lightness of the flour ranged from 1197.5–2971.5 cP and 65.5–87.0 respectively; both parameters increased with higher pearling times and moisture content. Practical applications In this research, we produce sorghum flours from two hybrids of brown and one white sorghum. The pearling process followed by impact milling, and roller milling are commonly used in the industry, but there is not enough in-depth knowledge about the characteristics of the sorghum flour produced. This work emphasizes the different alternatives for grain conditioning before milling and also evaluates the physicochemical and technological properties of the flours obtained. We consider that the results represent a very important contribution to the sorghum flour industry. These provide relevant information to choose the most suitable milling conditions to obtain flour with the desired characteristics depending on its final use.