High-shear Process Research Articles

Novel Magnesium Nanocomposite for Wire-Arc Directed Energy Deposition.

Magnesium alloys play an essential role in metallic lightweight construction for modern mobility applications due to their low density, excellent specific strength, and very good castability. For some years now, degradable implants have also been made from magnesium alloys, which, thanks to this special functionality, save patients a second surgery for explantation. New additive manufacturing processes, which are divided into powder-based and wire-based processes depending on the feedstock used, can be utilized for these applications. Therefore, magnesium alloys should also be used here, but this is hardly ever implemented, and few literature reports exist on this subject. This is attributable to the high affinity of magnesium to oxygen, which makes the use of powders difficult. Therefore, magnesium wires are likely to be used. In this paper, a magnesium-based nanocomposite wire is made from an AM60 (Mg-6Al-0.4Mn) (reinforced with 1 wt% AlN nanoparticles and containing calcium to reduce flammability), using a high-shear process and then extruded into wires. These wires are then used as feedstock to build up samples by wire-arc directed energy deposition, and their mechanical properties and microstructure are examined. Our results show that although the ductility is reduced by adding calcium and nanoparticles, the yield strength in the welding direction and perpendicular to it is increased to 131 MPa.

The Effect of Water, Nanoparticulate Silica and Dry Water on the Flow Properties of Cohesionless Sand

Cement hydration within particle bed concrete 3D printing processes can be benefited by storing water in the otherwise dry aggregate bulk material. Additional water also has the advantage of acting as a source of passive cooling. However, even small amounts of liquid lead to detrimental effects on bulk properties, such as the flowability. For that reason, this study proposes implementing dry water (DW) in order to store large amounts of water in a bulk material of non-absorbent, coarse sand whilst maintaining its initial bulk properties. DW is essentially created by mixing water and hydrophobic fumed silica in a high shear process, leading to water droplets surrounded by a protective silica shell. Herein, several DW variants, distinguished by their deionised water to hydrophobic silica ratio, were mixed with non-absorbent, coarse sand particles. In addition, mixtures were produced to contain a specific overall water content of up to wH2O = 5% within the bulk material. It was shown that dry water can be used to incorporate large amounts of water into a granular bulk material and simultaneously preserve flow properties. The decisive factor is the proportion of hydrophobic silica for a given water content as the DW capsules may otherwise not endure mechanical stress during mixing. However, even minimal quantities of silica can prevent liquid capillary bridges from forming and, thus, inhibit bulk property degradation.

Effect of ash in paper sludge on enzymatic hydrolysis

The valorization of paper sludge is a high-potential process to develop renewable fuels and chemicals, which can be integrated with pulp and paper mills. Calcium carbonate is the main ash component in sludge, which plays a role in buffering pH and potentially lowering the conversion during enzymatic hydrolysis. Therefore, it is important to investigate the effect of ash on sugar yields and examine pH change to introduce efficient and economical enzymatic hydrolysis of sludge. Carbohydrate conversion was enhanced when the ash was removed by fractionation. On the other hand, the highest sugar recovery was obtained when the sludge contained 20% ash content. The pH change during enzymatic hydrolysis was influenced by ash and explained why sludge-derived hydrolysate showed lower carbohydrate conversion. Therefore, a high shear process with the increased acid amount is suggested to prohibit the negative effect of ash and enhance the accessibility of cellulase to fibers. This study highlights the feasibility of using wet waste streams generated by the paper industry.

Circular Manufacturing and Direct Recycling of Li-Ion Batteries Electrodes Via Solventless Melt Process

The expansion of the electric vehicles (EV) market demands new green fabrication methods of lithium-ion batteries (LIBs), a crucial component of EVs. At the same time, it provokes a dramatic increase of production scrap volume of LIBs with more and more EV batteries reaching end-of-life in the next years. LIBs are hazardous, posing chemical and fire risks, especially at their end-of-life. Considering their growing volume, disposal in landfill is no more an acceptable option. Furthermore, LIBs contain high-value materials (cobalt, nickel, lithium...), many of which are mined and produced via unsustainable or unethical supply chains. Thus, it becomes important to manufacture, salvage and recycle LIBs safely, responsibly and by minimizing production residues. Current recycling processes, namely pyrometallurgy and hydrometallurgy are complex, energy intensive and/or requiring large amounts of water and other chemicals for the separation of valuable elements and the preparation of new active materials.We have developed an inexpensive original melt solventless high-shear process for the manufacturing of Li-ion cathodes and anodes as well as the direct recycling of scrap electrodes and used electrodes. This process is adapted to a variety of electrodes morphologies and chemistries. This process consists in the following steps:- First, active filler dispersions are obtained in the melt using a combination of a permanent binder at low content < 3 wt% and an inexpensive commercial sacrificial binder. The sacrificial binder is a mixture of commercially available polymers made from conversion of carbon dioxide CO2.- The dispersions are then cast on the current collector using a calendaring process to yield 50-250 µm coatings depending on the final application (both high-energy and high-rate are possible).- The sacrificial binder is then degraded thermally at high speed at low temperature below 250°C to yield an electrode of tailored porosity possessing an improved adhesion to the collector compared to conventional PVDF solvent processed electrodes.Melt formulations were developed for several conventional Li-ion cathodes, namely LFP, NCA, NMC and conventional Li-ion anodes. A large range of loadings could be achieved, from 4 to 40 mg/cm2. Electrochemical performances in half cells will be presented, demonstrating high capacity and cyclability for high loadings, as well as the performances at high rates, up to 10 C.Important benefit of our process is reusage of already manufactured electrode material. Fabricated electrode material can be mixed with fresh blend to process a new electrode. Both cathode (NMC 622 and LFP) and anode (graphite) scraps were sucessfully remanufactured. The reprocessing does not alter electrode performance, even if we completely reuse old electrode material without diluting it into a fresh melt. That means that all scrap could be subsequently reprocessed without change in electrode performance.Moreover, the developed melt process is capable to reintegrate used cathode or anode material removed from its current collector (i.e. black mass) giving a new functional electrode. Such electrode material to be recycled can be initially manufactured via conventional solvent (NMP or aqueous) process with conventional binders (PVDF, CMC). Direct incorporation of up to 25 wt% recycled electrode materials including binders and conductive additives from used lithium-ion batteries into fresh electrode compositions in one step has been demonstrated. At our knowledge, that is a sole process able to directly recycle all electrode material without separation of active material from conductive carbon black and binder. Therefore, the presented melt process will illustrate shortening and better valuation of the battery production supply chain. Figure 1

The Dimerization of Acetylene Catalyzed by Modified Catalyst and Enhanced by High Shear Process

The Dimerization of Acetylene Catalyzed by Modified Catalyst and Enhanced by High Shear Process

Production of Sacha Inchi oil emulsions by high‐shear and high‐intensity ultrasound emulsification: Physical properties and stability

This study investigated the physical properties and stability of Sacha Inchi oil-in-water emulsions prepared by means of high-shear and high-intensity ultrasound-assisted emulsification, using maltodextrin and a modified starch (Hi-Cap® 100) as stabilizing agents. The obtained emulsions exhibited particle sizes between 0.10 and 2.75 μm, and span values ranging from 1.39 to 2.64. Their ζ-potentials around −25 mV and the high resistance to aggregation by electrolytes suggest a predominantly electrosteric stabilization mechanism. Both the preparation method and the oil loading influenced the properties and stability of the emulsions. Ultrasound-assisted emulsification produced emulsions with slightly wider droplet size distribution, higher viscosity, and lower stability over time, than those obtained via the high-shear process. As the oil loading increased from 20% to 30%, the viscosity significantly increases, and all emulsions exhibited a shear-thinning behavior that fits well to the Herschel-Bulkley model. Practical applications Sacha Inchi oil is a promising product for applications in the formulation of functional foods. However, because of its high degree of unsaturation, it is not easy to add into food products due to its oxidation susceptibility. Oil-in-water emulsions are suitable systems with a wide range of applications in the food industry. Sacha Inchi oil emulsions prepared by either high-shear or ultrasound-assisted emulsification offer an alternative to taking advantage of the unique nutritional properties of this oil, rich in alpha-linolenic and linoleic acids, which have proved to have bioactive properties.

Virtual Experiments of Particle Mixing Process with the SPH-DEM Model.

Particle mixing process is critical for the design and quality control of concrete and composite production. This paper develops an algorithm to simulate the high-shear mixing process of a granular flow containing a high proportion of solid particles mixed in a liquid. DEM is employed to simulate solid particle interactions; whereas SPH is implemented to simulate the liquid particles. The two-way coupling force between SPH and DEM particles is used to evaluate the solid-liquid interaction of a multi-phase flow. Using Darcy’s Law, this paper evaluates the coupling force as a function of local mixture porosity. After the model is verified by two benchmark case studies, i.e., a solid particle moving in a liquid and fluid flowing through a porous medium, this method is applied to a high shear mixing problem of two types of solid particles mixed in a viscous liquid by a four-bladed mixer. A homogeneity metric is introduced to characterize the mixing quality of the particulate mixture. The virtual experiments with the present algorithm show that adding more liquid or increasing liquid viscosity slows down the mixing process for a high solid load mix. Although the solid particles can be mixed well eventually, the liquid distribution is not homogeneous, especially when the viscosity of liquid is low. The present SPH-DEM model is versatile and suitable for virtual experiments of particle mixing process with different blades, solid particle densities and sizes, and liquid binders, and thus can expedite the design and development of concrete materials and particulate composites.

Apple puree's texture is independent from fruit firmness

How cellular and molecular structure of raw fruits impact puree's texture is still an unresolved question. Texture variations of purees obtained from four apple cultivars of contrasted texture (Braeburn, Gala, Golden Delicious, Granny Smith) and two modalities (mealiness, fruit load) after two contrasted processes were investigated. Although puree's viscosity strongly varied between cultivars (562–1368 mPa s), it did not correlate with apple firmness, except for Granny Smith. This cultivar had the firmest fruits (3.2 N) and the most viscous purees (1368 mPa.s), in accordance with large particles (around 650 μm), high pulp wet mass and serum viscosity. Mealy Braeburn apples showed lower puree's viscosity (562 mPa.s) than their not-mealy homologues (779 mPa.s). This was due to reduced cell adhesion, maybe because of lower (arabinose + galactose)/rhamnose ratio, leading to smaller particles during processing. Process also impacted puree's viscosity (692–939 mPa s), with more viscous purees obtained with the high temperature-low shear process.

Evaluation of amaranth flour processing for noodle making

Amaranth is an ancient grain that is high in gluten-free protein and is a drought tolerant crop. Due to growing consumer interest in nutrition and environment, there is a renewed interest in ancient crops such as amaranth. The objective of this study was to evaluate processing methods such as dry roasting and jet-cooking of amaranth flours for making high protein, gluten-free noodles. Commercial amaranth flour was processed by dry roasting and excess steam jet-cooking. The raw and processed flours were evaluated for proximate and amino acid composition, physical properties such as bulk density, water absorption, and pasting and properties and compared to wheat flour. The noodle dough and noodles made using the three amaranth flours and wheat flour were evaluated for texture, color, and cooking quality. Raw amaranth flour had higher protein, ash, and fat content but lower starch content when compared to wheat flour. Processing of amaranth flour did not affect the protein, starch, and ash content of amaranth flours. Bulk density of raw amaranth flour was significantly lower than wheat flour roasting did not affect the bulk density, but jet-cooking decreased the bulk density. Raw amaranth flour had higher peak viscosity than wheat flour. The jet-cooked amaranth flour had a shorter hydration time, lower peak viscosity, and low setback. Raw Amaranth noodle dough was softer but roasted amaranth flour did not significantly differ in dough hardness from wheat flour dough. The noodles made from raw and processed amaranth flours were softer than wheat flour noodles. Amaranth flour noodles had a softer bite than wheat flour noodles, roasting increased the hardness of the amaranth flour noodles. Raw and roasted amaranth flours had similar cooking yields as wheat flour, but jet-cooked amaranth flour noodles had higher cooking losses and partially disintegrated during cooking. Roasted amaranth flour has potential for replacing wheat flour in the preparation of acceptable gluten-free, nutritive noodles. Practical Application Roasted amaranth flour has potential for replacing wheat flour in the preparation of acceptable gluten-free, nutritive noodles. Amaranth crop is drought tolerant, and amaranth grain is high in protein, rich in essential amino acids and is gluten- free. Roasting a simple dry heat process and jet-cooking a high heat and shear process was applied to improve the nutrition and digestibility of amaranth flour. The raw, roasted, and jet-cooked amaranth flour was evaluated, and characteristics compared to wheat flour. Noodles made from amaranth flours were compared to wheat flour noodles. This work demonstrates that roasting improved the cooking yield and texture of cooked noodles. This will expand utilization of amaranth and contribute to the sustainability of U.S. agriculture in the era of climate change.

Gluten extraction from deoxynivalenol contaminated wheat by wet milling

The wet milling process can be a valuable alternative for deoxynivalenol (DON) contaminated wheat grain, taking advantage of DON water solubility. The present research was conducted on hard red spring wheat (HRSW) and durum wheat (DW) samples contaminated with DON. The wheat samples were dry milled into farina and semolina, which were further subjected to three different small-scale wet milling tests, dough-washing (Martin process), moderately sheared dough-water dispersion (medium shear) process, and highly sheared flour-water dispersion (high shear) process. Gluten samples extracted from all the wet milling processes had DON levels below the limit of quantification (<0.2 mg/kg) because of the high water solubility of DON. Size-exclusion HPLC revealed that gluten samples obtained from medium shear and high shear processes were composed of more unextractable (sonication extractable) glutenin macropolymers and less gliadin fractions than those obtained from the Martin process. This yielded better rheological performance for the gluten samples, so that they were quite similar to the control (commercial wheat gluten), which means the gluten samples exhibited a potential application as food ingredients.

Determination of significant factors in high-shear granulation process of sucrose with aqueous solution of sodium lauryl sulphate using partial least square regression approach

Sucrose as one of the most commonly used raw materials in pediatric formulations is soluble and sticky excipient and its manipulation in high shear granulators may be very difficult. Therefore, to determine the correct amount of liquid binder is very important because it falls in a very narrow range and may vary due to small variations in the material properties or environmental conditions. The possibility of using the sugar as powder for granulation may be very challenging because of solubility and moisture adsorption properties of crystalline sugar, especially if the binder solution is water. The aim of this study was trying to solve these problems and produce sucrose granules using high share granulation and water as a binding liquid, with properties required for final product good performance. By reducing the sucrose particle size and improving the uniformity of the size distribution, the differences of the processes of nucleation and growth for small and large particles might be reduced. According to the variable importance or VIP scores from the developed partial least square (PLS) model, raw material particle size is as influential variable as the quantity and composition of the granulation liquid (Gra), granulation time (Grn) and impeller rate (Imp). Keywords: sucrose, particle size distribution, high-shear granulation, partial least square

Stability, physical properties and acceptance of salad dressings containing saffron (Crocus sativus) or pomegranate juice powder as affected by high shear (HS) and ultrasonication (US) process

The influence of preparation method, high shear (HS) or ultrasonic (US) homogenization on stability, physical and sensory attributes of salad dressings containing saffron and pomegranate juice has been investigated upon 6 months of ambient storage. Emulsified dressings were evaluated for stability, microstructure, viscoelastic properties, and acceptance. All samples processed by HS showed higher apparent viscosity, yield stress (τ0), storage and loss moduli (G′, G″), particle diameters, yellow-blue color (b values) and lower lightness (L) compared to their US counterparts. Ambiguous results depending on added constituents (saffron or pomegranate juice) were obtained regarding long term stability and red-green color (a), whereas total color change (TCD) of samples was unaffected. Pomegranate dressings prepared with HS exhibited enhanced viscoelastic character and high stability during storage (Back scattering variation, dBS ∼ 1%). US samples were equally accepted as their HS counterparts by panelists for most sensory attributes, but sonication clearly improved the color likeness of samples containing pomegranate by 51%. Saffron addition significantly improved the taste of the dressings.This study shows that ultrasonication may be used to ameliorate color attributes related to pomegranate juice addition homogenizating successfully these products without detrimental effects on their long-term stability i.e. product syneresis.

Effect of production parameters and stress conditions on beta-carotene-loaded lipid particles produced with palm stearin and whey protein isolate

Abstract Microencapsulation is currently used by the food industry for different purposes, including the protection of ingredients against factors such as oxidation and volatilization, as well as to increase the bioavailability and bioaccessibility of nutrients. The current study aimed to encapsulate beta-carotene in solid lipid microparticles stabilized with whey protein isolate (WPI), and also investigate their integrity during storage and under stress conditions such as different ionic strengths, sucrose concentrations and thermal treatments. Solid lipid microparticles were produced using palm stearin, a food grade vegetable fat, using a single-step high shear process. Of the different formulations used for lipid microparticle production, characterization studies showed that the greatest stability was obtained with systems produced using 1.25% (w/v) whey protein isolate, 5% (w/v) palm stearin and 0.2% (w/v) xanthan gum. This formulation was applied for the production of beta-carotene-loaded solid lipid microparticles, with different concentrations of alpha-tocopherol, in order to verify its possible antioxidant activity. The results showed that the addition of alpha-tocopherol to the dispersions provided an increase in encapsulation efficiency after 40 days of storage that ranged from 29.4% to 30.8% when compared to the system without it. Furthermore, the solid lipid microparticles remained stable even when submitted to high ionic strength and to heating in the proposed temperature range (40 °C to 80 °C), highlighting their feasible application under typical food processing conditions.

Production of Cornstarch Granules Enriched with Quercetin Liposomes by Aggregation of Particulate Binary Mixtures Using High Shear Process.

This study is an unprecedent association of 2 technologies, nanoencapsulation and wet agglomeration, here used together to enrich cornstarch with quercetin. The agglomeration process was used to obtain granules of cornstarch, an ingredient extremely used in the food industry, enriched with quercetin-loaded lyophilized liposomes. The goals were both the improvement of the nutritional quality and the increase of the added value of the cornstarch.

Melt Conditioning of Light Metals by Application of High Shear for Improved Microstructure and Defect Control

Casting is the first step toward the production of majority of metal products whether the final processing step is casting or other thermomechanical processes such as extrusion or forging. The high shear melt conditioning provides an easily adopted pathway to producing castings with a more uniform fine-grained microstructure along with a more uniform distribution of the chemical composition leading to fewer defects as a result of reduced shrinkage porosities and the presence of large oxide films through the microstructure. The effectiveness of high shear melt conditioning in improving the microstructure of processes used in industry illustrates the versatility of the high shear melt conditioning technology. The application of high shear process to direct chill and twin roll casting process is demonstrated with examples from magnesium melts.

Colloidal Properties of Nanoerythrosomes Derived from Bovine Red Blood Cells.

Liposomes are nanoscale containers that are typically synthesized from lipids using a high-shear process such as extrusion or sonication. While liposomes are extensively used in drug delivery, they do suffer from certain problems including limited colloidal stability and short circulation times in the body. As an alternative to liposomes, we explore a class of container structures derived from erythrocytes (red blood cells). The procedure involves emptying the inner contents of these cells (specifically hemoglobin) and resuspending the empty structures in buffer, followed by sonication. The resulting structures are termed nanoerythrosomes (NERs), i.e., they are membrane-covered nanoscale containers, much like liposomes. Cryo-transmission electron microscopy (cryo-TEM) and small-angle neutron scattering (SANS) are employed for the first time to study these NERs. The results reveal that the NERs are discrete spheres (∼110 nm diameter) with a unilamellar membrane of thickness ∼4.5 nm. Remarkably, the biconcave disc-like shape of erythrocytes is also exhibited by the NERs under hypertonic conditions. Moreover, unlike typical liposomes, NERs show excellent colloidal stability in both buffer as well as in serum at room temperature, and are also able to withstand freeze-thaw cycling. We have explored the potential for using NERs as colloidal vehicles for targeted delivery. Much like conventional liposomes, NER membranes can be decorated with fluorescent or other markers, solutes can be encapsulated in the cores of the NERs, and NERs can be targeted to specifically bind to mammalian cells. Our study shows that NERs are a promising and versatile class of nanostructures. NERs that are harvested from a patient's own blood and reconfigured for nanomedicine can potentially offer several benefits including biocompatibility, minimization of immune response, and extended circulation time in the body.

High shear dispersion of tracers in polyolefins for improving their detection

An efficient recycling of end-of-life products is of crucial interest from an economical and ecological point of view. However, the near infrared spectroscopy often used for the optic sorting processes is limited because of the absorption of carbon black present in black plastics and as it only sorts as a function of chemical formulas. The tracing technology developed in this study is based on the dispersion of lanthanide complexes particles into polymers to give them a code that can be related to their formulation and viscosity that are important parameters for their re-processing. As the success of this technology is conditioned by achieving a fine dispersion of the tracer particles, we also focus on accomplishing a fine dispersion of tracer particles by using a high shear process. Processing under high shear rate (N= 800 rpm) has proved to play a determining role in dispersing finely and homogenously tracer particles within PP matrix. Thanks to the good quality of dispersion, the detection of three tracers at a level of 0.1 wt% has been successfully achieved, even in black matrices for an acquisition time of 10 ms.

Subsurface characterisation of wear on mechanically polished and electro-polished biomedical grade CoCrMo

CoCrMo alloys have been widely used for metal-on-metal total hip replacements (THRs). However, the use of the metal-on-metal implants has recently been seriously called into question due to adverse local tissue reactions due to the response of the body to wear debris and corrosion products. It is important to understand the wear of metal-on-metal THRs, hence to reduce the wear rate and metal ion dissolution. A nanocrystalline layer has been reported on the topmost surface of both in vivo and in vitro CoCrMo THRs and is believed to play a key role in the wear resistance of the material. The current work provides a detailed study of surface damage of biomedical CoCrMo after reciprocating wear testing. Systematic differences in the starting surface structure were investigated through a comparison of a standard mechanical polished and an electropolished surface. Extensive use of cross-sectional transmission electron microscopy (TEM) was applied to evaluate the evolution of the nanocrystalline layer. It was found that the nanocrystalline layer was not observed in cross-section samples from the as-mechanically polished surface, however there was extensive formation of ε-martensite and mechanical twins. In contrast, the electro-polished surface exhibited minimal evidence of deformation. The nanocrystalline layer developed during sliding contact for both starting surfaces, but at different rates. For the mechanically polished surface, the nanocrsytalline layer was far more extensive than for the electro-polished surface. Thus, this suggests that the nanocrystalline layer forms through some high strain shear process from the prior ε-martensite structure, and that a minimum plastic strain is required in the surface before the nanocrystalline layer starts to form. The formation mechanisms are discussed in detail.

Development of a novel pelletization technique through an extremely high-shear process using a mechanical powder processor to produce high-dose small core granules suitable for film coating

We established an extremely high-shear melt pelletization technique using a mechanical powder processor to produce high-dose granules smaller than 300μm with properties suitable for film coating. A mixture of ethenzamide and polyethylene glycol (used as a low-melting binder) at various weight ratios was mechanically treated under various jacket temperatures. When the jacket temperature was set to 50°C or greater, the product temperature reached the melting point of the binder, resulting in pelletization. The drug powder were pelletized with a small amount of binder to yield pellets of approximately 150μm with a drug content of more than 90%. The mechanism of melt pelletization through ultrahigh shearing involves a series of nucleation, consolidation, coalescence and breakage stages. The power consumption profile corresponding to each stage in the pelletization revealed that pellets between 75 and 300μm were effectively obtained at a large power consumption peak. The resultant pellets showed comparative sphericity and smoothness, and higher durability than commercial core granules for film coating. In conclusion, this study demonstrates that the extremely high-shear melt pelletization technique can give drug pellets with desirable properties as core particles for the coating process.

Compartment based population balance modeling of a high shear wet granulation process using data analytics

Population balance models (PBMs) are used extensively to model various particulate processes such as granulation. A high shear granulation process is often assumed to be well mixed and is represented using a single compartment PBM. However, the inhomogeneities existent within the granulator are not effectively addressed using the single PBM representation for the process. Thus, a multi-compartment model is needed to account for the inhomogeneities within the granulator. In this study, the multiple compartments are identified from data mining methods (e.g. clustering) and their average values are thereby obtained. Using regression analysis, a general expression is obtained for the size of the compartments and the average values for different operating conditions. These expressions are then used within a multi-compartment PBM formulation to describe the process dynamics. Validation for the regression expressions also showed good agreement against the varying operating conditions. Also, the multi-compartment model is able to account for mechanical dispersion behaviors that is typically associated with a high-shear process. This study shows that the assumption of a single compartment for a high-shear granulator is often inadequate and the multi-compartment based approach can offer a better physical representation of the process.