Optimal Mixing Conditions Research Articles

The Role of Mechanical Mixing and Biologically Active Additives in Enhancing Cutlet Quality

The research relevance is determined by the need to understand the effect of mechanical mixing and the use of biologically active additives on the quality of cutlet mass, which will optimize food technologies and create products with improved texture and nutritional value. This need stems from the fact that the quality and characteristics of culinary products are important criteria for consumers. The research aims to investigate the relationship between mechanical mixing parameters and the use of biologically active additives with structural and mechanical quality parameters of cutlet mass, to improve production processes and develop higher quality food products. Analytical methods, classification methods, functional methods, statistical methods, and synthesis methods were used to determine the quality of the cutlet mass. In the course of the study, a comprehensive analysis of the effect of various parameters of mechanical mixing and the use of various biologically active additives on the structural and mechanical characteristics of the cutlet mass was carried out. It was found that optimal mixing conditions and types of additional components can significantly improve the textural properties of the product. It was found that the use of certain biologically active additives helps to increase the resistance of the mass to mechanical stress and preserve its juiciness. These conclusions allow us to develop more effective strategies for the production of cutlet mass with improved quality and nutritional value. The practical significance of this study is to provide scientifically based recommendations for optimizing food production processes aimed at improving the quality and nutritional value of cutlet mass by studying the effect of mechanical mixing and biologically active additives on its structural and mechanical properties.

Study of moisture sorption thermodynamic in canola oilseed and drying energy requirement considerations

AbstractThe objective of this study is to derive the thermodynamic characteristics from sorption isotherm data for canola. The semi‐gravimetric method was utilized at three different temperatures (25, 40, and 55°C) and seven air relative humidity levels within the range of 11%–90%. The observed data indicated that the equilibrium moisture content of the sample decreased as the temperature increased. The “GAB and BET” models were applied to fit the empirical data, which demonstrated a Type III isotherm, and the monolayer water content was subsequently determined using these models. Thermodynamic properties such as “isosteric heat,” “net isosteric heat,” “differential entropy,” “net integral entropy,” and “net integral enthalpy” were determined from isothermal sorption curves. The results show that as moisture content increases, both the sorption isosteric heat and the differential entropy of sorption decrease. This indicates that at higher moisture levels, the energy required for additional moisture adsorption and the changes in entropy are reduced. Similarly, the net isosteric heat of sorption and the net integral enthalpy of sorption also decrease with increasing moisture content, consistent with the observed reductions in isosteric heat and differential entropy. The specific absorption surface area for each temperature was determined by calculating the monolayer moisture content using both the “GAB and BET models.” The net integral entropy had an increasing trend in the range of 4%–4.5% (db%), while it decreased in the range of 4.5%–6.8% of moisture content. In addition, the spreading pressure at three levels of temperature was reported. Finally, an empirical relation was employed to illustrate the cumulative energy requirement for drying versus moisture content. The results indicated that at low moisture content levels, the drying process required significantly higher energy.Practical applicationsMoisture sorption isotherms are essential for understanding the interaction between water and food ingredients. This knowledge is vital for improving food processing methods such as drying, mixing, cooling, and storage. In industry, isotherms can help determine the best drying method to maintain food quality, identify the optimal mixing conditions to ensure consistency, establish cooling protocols to prevent spoilage, and set storage guidelines to extend shelf life. In addition, understanding thermodynamic properties is crucial for regulating moisture absorption and release, achieving the desired food texture, managing surface characteristics, and calculating the energy needed for effective dehydration processes.

Mild Approach for the Formulation of Chestnut Flour-Enriched Snacks: Influence of Processing Parameters on the Preservation of Bioactive Compounds of Raw Materials.

Third-generation snacks were developed from a triad of flours made up of chestnut, spelt, and chickpea flour. Optimal snack formulations and processing parameters have been established to ensure acceptable workability of the raw dough while protecting the bioactive components of the raw materials. The parameters examined were mixing time, speed, and temperature. The properties of the snack were evaluated by analyzing the expansion ratio, hardness, moisture content, and phenolic and volatile compounds. The optimal mixing conditions that ensure maximum expansion were a temperature of 30 °C, a speed of 30 rpm, and a time of 6 min. The results showed that the proper percentage of water and sodium bicarbonate was 35% and 2%, respectively, and that the developed snacks had an alveolar and homogeneous structure. The proposed approach brings several advantages, including the preservation of bioactive compounds during the production process. Furthermore, the mild operating conditions prevented the development of unwanted or unpleasant compounds, as confirmed by the analysis of volatile compounds. Therefore, this study opens new perspectives in the food industry, satisfying the growing demand for functional products and healthy snacks.

Study on the mechanical behavior of microcapsules during the mixing process of asphalt mixture

To enhance the survival rate of microcapsules during the mixing process of asphalt mixture, the mechanical behavior of microcapsules during this process was investigated through simulation. Initially, the asphalt mixture containing microcapsules was divided into mesoscopic and microscopic scales. Utilizing composite material models, the stepwise inclusion method and high-temperature tensile tests, the equivalent mechanical parameters for the microcapsules, asphalt mastic and asphalt mortar at mixing temperature were estimated. Following this, the mixing process of the asphalt mixture incorporating microcapsules was simulated employing the discrete element method (DEM) coupled with multi-body dynamics (MBD). This simulation was instrumental in identifying optimal mixing parameters and enabled the analysis of force chain transmission across the multi-scale model. Furthermore, the finite element method (FEM) was employed to develop a monomer model of the microcapsules, facilitating the assessment of their mechanical behavior under optimal mixing conditions. Finally, a detailed sensitivity analysis was performed to investigate the influence of various parameters on the mechanical behavior of microcapsules. The results indicated that, at the mixing temperature, the equivalent Young’s modulus and Poisson's ratio for urea-formaldehyde (UF) resin microcapsules, asphalt mastic, and asphalt mortar were determined to be 0.22 GPa and 0.478, 19.87 GPa and 0.4986, and 88.77 GPa and 0.468, respectively. The optimal mixing parameters for AC-16 asphalt mixture including mixing speed, filling rate and mixing duration were identified as 49 rpm, 50 % and 53 s, under which the most adverse load on the microcapsule is 80 mN. Under the most adverse load, microcapsules might rupture from the inside out, and their survival rate was not less than 68.9 %. Increasing the particle size of microcapsules and reducing the relative radius of the microcapsule core could potentially enhance the crack resistance of microcapsules during mixing.

Degradation during Mixing of Silica-Reinforced Natural Rubber Compounds.

The optimal mixing conditions for silica-filled NR compounds dictate the need to proceed at a high temperature, i.e., 150 °C, to achieve a sufficient degree of silanization. On the other hand, natural rubber is prone to degradation due to mechanical shear and thermal effects during mixing, particularly at long exposure times. The present work investigates NR rubber degradation during mixing in relation to prolonged silanization times. The Mooney viscosity and stress relaxation rates, bound rubber content, storage modulus (G'), and delta δ were investigated to indicate the changes in the elastic/viscous responses of NR molecules related to rubber degradation, molecular chain modifications, and premature crosslinking/interaction. In Gum NR (unfilled), an increase in the viscous response with increasing mixing times indicates a major chain scission that causes a decreased molecular weight and risen chain mobility. For silica-filled NR, an initial decrease in the Mooney viscosity with increasing silanization time is attributed to the chain scission first, but thereafter the effect of the degradation is counterbalanced by a sufficient silanization/coupling reaction which leads to leveling off of the viscous response. Finally, the higher viscous response due to degradation leads to the deterioration of the mechanical properties and rolling resistance performance of tire treads made from such silica-filled NR, particularly when the silanization time exceeds 495 s.

Effect of temperature, geometric parameters, and surface conditions on fluid mixing in a vertical port static mixer

This study comprehensively investigates how elevated temperature and surface roughness affect vertical liquid jet mixing in a multi-port nozzle, using both experimental and computational methods. It explores various geometrical parameters and precise nozzle positioning. Experiments, conducted across different temperature and surface roughness conditions, involve adjusting convergent nozzle angles, driving nozzle distance from the throat, and insert presence. Conductivity probes, turbidity meters, and pH meters quantify fluid mixing under diverse conditions. Optimal mixing conditions for vertical flow secondary fluid inlets are determined, along with corresponding mixing efficiencies for each port. Computational fluid dynamics (CFD) simulations with ANSYS Fluent R2 2001 confirm that the highest mixing efficiency of nearly 98% is achieved with an elevated temperature of 50 °C, a rough-surfaced convergent nozzle, a helical insert, and a 45 mm driving nozzle distance, when all vertical ports are open simultaneously. These findings advance understanding of optimizing vertical-flow mixing in multi-port static mixers under varying conditions.

Aeolian sand stabilized by using fiber- and silt-reinforced cement: Mechanical properties, microstructure evolution, and reinforcement mechanism

Northwest China has a large amount of aeolian sand, which exhibits poor gradation, low cohesive force, and loose structure; thus, this sand is difficult to be directly used as engineering construction materials. To solve this problem, this study mixed fiber, silt, and cement to stabilize aeolian sand. The effects of the fiber content (0%, 0.5%, 1%, 2%, 3%, and 4%), fiber length (6, 12, and 19 mm), silt content (10%, 15%, and 20%), and curing time (7, 14, and 28 d) were evaluated by conducting indoor unconfined compressive strength tests, and the strength prediction and constitutive models were established. In addition, the microstructural and pore variation characteristics were studied by performing scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and nuclear magnetic resonance (NMR) tests, and the stability mechanism was elucidated. The results showed that the addition of fibers and silt can significantly improve the strength and ductility of cement-stabilized aeolian sand. Under the optimal mixing conditions (fiber length: 12 mm; fiber content: 2%; silt content: 15%), the strength of the sample increased by 274.2% (reaching 1684 kPa) compared with that of cement-stabilized aeolian sand (450 kPa). A positive correlation was observed between the curing time and strength development of the samples. The established strength prediction model effectively predicted the strength variations in the specimens, whereas the constitutive model accurately reflected the stress-strain relationship of the specimens. The SEM results revealed that the coupling effect of fibers, silt, and cement makes the specimens more compact and improves the overall stability. The results of the NMR showed that the numbers of macropores and mesopores decreased significantly and that the numbers of small pores and micropores increased with 2% fiber content; the porosity of the specimen was 12.3%, which was 28.6% lower than that of ordinary-cement-stabilized aeolian sand. This study advocates making full use of local silt to stabilize aeolian sand, which has significant advantages in terms of improved mechanical properties, environmental protection, and reduced project costs compared with traditional cement-stabilized aeolian sand. The results of this study have important theoretical and practical significance for the engineering and design of projects in aeolian sand areas.

Analysis and optimization of heterogeneously charged surface features in electrokinetic micromixing of non-Newtonian fluids

This study investigates the mixing of non-Newtonian fluids in microfluidic devices using electrokinetic phenomena Micromixing is a crucial operation that finds multiple applications in chemical research and biomedical diagnostics. In order to improve mixing, multiple combinations of heterogeneously charged triangular elements are considered for investigation. The power-law model was used to characterize the non-Newtonian behavior of fluids. The effect of different geometrical parameters (hurdle length, height, number, and shape) and electrical parameters (applied external electric field and zeta potential on hurdles) on mixing are evaluated. The results indicate that the element shape, number, and fluid viscosity significantly affect mixing in microchannels. Moreover, the homogeneity of the mixed fluids increases with the flow behavior index (n). We found that dilatant fluids mix relatively better than pseudoplastic fluids. Finally, the Taguchi technique used to evaluate the combined effect of all factors and obtained optimal mixing conditions for various flow behavior indices (n) of non-Newtonian fluids.

Fluid mixing by an electromagnetically driven floating rotor.

We analyze the mixing properties of a floating stirrer driven electromagnetically in a thin layer of electrolyte, consisting of two free-floating magnets with opposite polarities connected by a rigid coupling. The magnetic rotor is set in circular motion using Lorentz forces created due to the interaction of the magnetic field of the rotor with dc currents actuated in logic sequence. We identify a coherent structure similar to a tripolar vortex whose central vortex rotates in the same direction of the rotor promoting chaotic mixing of the fluid in the laminar regime (Re=45). Dyed water visualization and particle image velocimetry were performed to characterize experimentally the mixing and flow dynamics at the surface of the electrolyte layer. A quasitwo-dimensional numerical simulation based on the immersed boundary method, which incorporates the fluid-solid interaction and reproduces the experimental observations satisfactorily, was carried out. Optimal mixing conditions are determined through the exponential growth of the material interfaces, which are established mainly by varying the distance separating the magnets of the rotor.

고령토 광물을 활용한 저 열팽창 코디어라이트 세라믹스 합성에 관한 연구

Cordierite (2MgO·2Al2O3·5SiO2) in the MgO·Al2O3·SiO2 system exhibits a low thermal expansion coefficient, high thermal shock resistance, low dielectric constant, and excellent electrical insulation properties. However, the material has a narrow sintering-temperature range. If the sintering temperature is too low, the crystal structure of cordierite does not form sufficiently; conversely, if it is slightly higher than ideal, the material decomposes into postelite, spinel, and mullite, leading to a significant increase in its thermal expansion coefficient. To overcome this problem, we adjusted the composition of cordierite by mixing it with predetermined amounts of kaolin minerals. After sintering at 1340℃, the resulting ceramic showed satisfactory physical properties, such as bulk density, absorption rate, and porosity. The optimal mixing conditions included a MgO/Al2O3 molar ratio of 1.006 and SiO2/Al2O3 molar ratio of 2.4277. Given its low thermal expansion coefficient(2.20 × 10−6/℃ at 800℃ and 2.57 × 10−6/℃ at 1000℃) and favorable physical and shrinkage properties, the cordierite prepared in this work may have potential applications in the development of kiln furniture materials for sintering next-generation secondary battery cathode materials.

Nucleation kinetics-based solvent selection for the liquid antisolvent crystallization of a lipophilic intermediate

The fundamental understanding of solubility and nucleation kinetics are two primary pillars for liquid antisolvent crystallization (LASC) process development. In our present work, the solubility of intermediate A in four different solvents and binary mixtures with water, in the temperature range from 273 K to 323 K, was determined using a liquid chromatographic method to acquire the fundamental thermodynamic information for the LASC process. Intermediate A was monitored both in the solid phase and in the liquid phase by in line Raman spectroscopy. The importance of selection of the optimum scale and mixing conditions (volume and fluid dynamics dependency) for conducting metastable zone width (MSZW) measurements for the nucleation kinetics study, due to stochastic nature of nucleation, has been demonstrated to translate the findings to larger industrial scales. The 3.5 mL volume in reactor with a 3 blade downflow overhead impeller in the Crystalline™ (Technobis) was found to be an optimal platform for the data generation for the extraction of nucleation kinetics. The minimum detection threshold value (fN) reported in the literature was experimentally derived for the intermediate A-solvent systems used, covering the effect of supersaturation, reaction volume and agitation rate. The combined polythermal and antisolvent addition approach was applied to determine MSZWs and, subsequently, the kinetic parameters were estimated based on both linearized integral and 3D nucleation models. It was demonstrated how the derived parameters complemented with accurate solubility data are required to guide solvent selection for bottom-up generation of nanosuspensions. The findings were validated by conducting batch and continuous LASC of intermediate A. Particle size distributions derived from electron scanning microscopy obtained at similar driving forces confirmed the solvents selection order based on their nucleation tendency of dissolved intermediate A. These results serve as an example for applying a nucleation kinetics-based fundamental approach for solvent selection in the development of LASC process for generation of long-acting injectable suspensions.

Abstract 21 High-Throughput Blood Separation System for CD34+ Cell Isolation

IntroductionResearch into the therapeutic roles and clinical potential of CD34+ cells is growing [Weissman and Shizuru, Blood. 2008;112(9):3543-3553]. Accordingly, advances in cell isolation methods have risen to meet the research demand. Cord blood banks have a unique opportunity to source CD34+ cells because of their relatively high prevalence in cord blood [Dauber et al. Cytotherapy. 2011;13(4):449-458]. However, current isolation systems are not optimized for processing cord blood, and even blood-compatible systems typically require the blood to be processed before use. FerroBio (www.42bio.com) has developed a magnetic separation system that facilitates scalable, high-volume cell isolation from complex biological fluids, such as blood, without pre-processing. This technology is now being adapted for CD34+ cell isolation from cord blood.ObjectiveIn this study, the conditions in which magnetic beads efficiently bind target cells were explored. The objective of this work was to evaluate optimal blood mixing conditions to bring beads into contact with cells in suspension in the blood. This will allow unmodified cord blood units (CBUs) to flow directly into our apparatus.MethodsThe FerroBio separation process is comprised of three simple steps (Figure 1A). Here, conditions of step 1 were explored to maximize target cell recovery and viability. Variables included type of agitation equipment (Figure 1B), temperature, time, and relative air volume in the blood bag. Recovery and viability were measured via flow cytometry and calculated relative to unprocessed blood from the same CBU.ResultsTwo mixing conditions were identified for maximum recovery of CD34+ cells (Figure 1C, blue bars). While not statistically different from each other, the Drum Roller method only requires one piece of standard equipment, is gentler, and can accommodate multiple CBUs simultaneously. No statistical difference in viability was observed in any conditions (90.7% ± 16.3%, n = 9). Increasing incubation time and the relative amount of air in the bag did not increase recovery (not shown).Figure 1. (A): Overview of the FerroBio Magnetic Separation Process, highlighting step (1) in which magnetic beads are mixed within the CBU to bind the target CD34+ cells. (B): Illustrations of the agitation equipment used to mix the CBU during step (1). (C): The resulting CD34+ recovery (1-way ANOVA, P = .0245). Image credit for panel (A): BioRender.DiscussionThe FerroBio separator can streamline CD34+ cell isolation by processing high blood volumes in a fast, closed system with high recovery rates. Additional studies are under way to evaluate the functionality of the isolated CD34+ cells and efficiency of bead removal.

Continuous Flow Labeling and In-Line Magnetic Separation of Cells

There is an identified need for point-of-care diagnostic systems for detecting and counting specific rare types of circulating cells in blood. By adequately labeling such cells with immunomagnetic beads and quantum dots, they can be efficiently collected magnetically for quantification using fluorescence methods. Automation of this process requires adequate mixing of the labeling materials with blood samples. A static mixing device can be employed to improve cell labeling efficiency and eliminate error-prone laboratory operations. Computational fluid dynamics (CFD) were utilized to simulate the flow of a labeling-materials/blood mixture through a 20-stage in-line static mixer of the interfacial-surface-generator type. Optimal fluid mixing conditions were identified and tested in a magnetic bead/tumor cell model, and it was found that labeled cells could be produced at 1.0 mL/min flow rate and fed directly into an in-line magnetic trap. The trap design consists of a dual flow channel with three bends and a permanent magnet positioned at the outer curve of each bend. The capture of labeled cells in the device was simulated using CFD, finite-element analysis and magnetophoretic mobility distributions of labeled cells. Testing with cultured CRL14777 human melanoma cells labeled with anti-CD146 1.5 μm diameter beads indicated that 90 ± 10% are captured at the first stage, and these cells can be captured when present in whole blood. Both in-line devices were demonstrated to function separately and together as predicted.

Chitosan/alginate composite porous hydrogels reinforced with PHEMA/PEI core–shell particles and pineapple-leaf cellulose fibers: their physico-mechanical properties and ability to incorporate AgNP

In this work, porous chitosan/alginate hydrogels (CS/Alg) were fabricated by the addition of two reinforcing fillers, PHEMA/PEI core–shell particles and pineapple-leaf cellulose fibers, using a freeze-drying method. At the optimum ratio and mixing conditions, the porous hydrogels obtained after freeze-drying showed an interconnected porous structure with pore size in a range of 50–100 µm and porosity in a range of 80–85%. With the incorporation of PHEMA/PEI core–shell particles and pineapple-leaf cellulose fibers, the composite hydrogels (CS/Alg/PF) maintained their structure when submerged in deionized water and acidic and basic media, with low volume shrinkage. Water adsorption reached equilibrium within 30 min, and the percentage water uptake ratios of CS/Alg and CS/Alg/PF in deionized water increased from 1165% to 1391%, largely due to the presence of pineapple-leaf cellulose fibers. However, the presence of both PHEMA/PEI particles and pineapple-leaf cellulose fibers increased the compressive modulus of the resulting hydrogels from 0.028 MPa to 0.083 MPa. Moreover, the pineapple-leaf cellulose fibers improved the storage modulus of the hydrogels as revealed by dynamic mechanical analysis. CS/Alg/PF was also utilized as a template for loading silver nanoparticles (AgNP) through a reduction reaction of silver ions at ambient temperature without the use of any additional chemical reducing agents. The physico-mechanical properties and antibacterial activity of the AgNP-loaded CS/Alg/PF hydrogels were evaluated as well.

Fabrication of extremely conductive high-aspect silver traces buried in hot-embossed polycarbonate films via the direct gravure doctoring method

Depositing inks on a planar substrate by printing is a facile way to fabricate conductive traces and other complicated functional devices. However, irrespective of the printing methods used, the thickness of the inks has an upper limit due to their fluidic property and subsequent wetting on the substrates. Herein, we present a method for creating high-aspect ratio conductive traces by combining hot-embossing and gravure doctoring techniques. Binary-sized colloidal pastes containing Ag nanoparticles and micrometer-sized spherical Ag powder additives were filled using a doctor blade in the grooves of polycarbonate (PC) films inscribed via hot-embossing to create buried traces. Under optimal mixing conditions in which the minimum resistivity was achieved, voids between the microparticles provided a pathway for the volatile solvents to smoothly escape from the filled ink and minimized thickness reduction during the thermal sintering process. A fabricated trace buried in the PC film with an aspect ratio of around 3:1 and a linewidth of 55 μm showed extremely low resistance of less than 10 Ω/m. A flexible transparent heater was developed using the reported binary colloidal paste.

Application of Chitosan from Corbula Faba Hinds shells as a Bio-Coagulant for River Water Treatment

Corbula faba Hinds or white mussel is one of the marine organisms easily found around Sidoarjo, East Java, Indonesia. The main component of its shell is chitin that can be derivate to chitosan. Chitosan is widely used especially in the water treatment process as a coagulant due to its biocompatibility and biodegradability. In this study, chitosan produced from white mussel shells was used as a coagulant for treated Surabaya River water. The initial value of TSS in the sample water was 373.0 mg/L whereas TDS was 59.5 mg/L. The rapid mixing condition, such as speed and time, influenced the result of solids removal. Higher speed and longer time mixing would give better performance of flocs formation, but the flocks would be unstable after reach some points of conditions. The optimum mixing condition was obtained when using140 rpm on speed for 4 minutes with TSS removal up to 94.96% and TDS removal up to 23.32%.

Mathematical and numerical predictions for optimum perfect mixing by bulk convective oscillatory exchange

The mixing quality for bulk convective oscillatory exchange are analyzed, modeled, and simulated for 24 cases mathematically and numerically. A new mathematical model has been derived for heat and mass transfer between two reservoirs to predict the perfect and optimum mixing quality. Two-dimensional axisymmetric simulations are carried out for incompressible viscous oscillatory flows. The computations are run for two reservoirs that are connected by a short duct over a unique range of the fluid’s axial displacements. From the mathematical model, two new equations for the instantaneous temperature in each reservoir have been derived to predict the perfect mixing quality for any bulk convective oscillatory exchange. According to the computational predictions, the mass exchange between the two reservoirs has been classified into five different regions depending on their mixing quality. Optimum perfect mixing conditions were obtained at a normalized fluid’s axial tidal displacement S¯=4.9 with mixing ratio ranged from 97%to100%. A new correlation for predicting the rate of heat transfer enhancement by the bulk convective oscillatory exchange is suggested. It is observed that the effective thermal conductivity has been enhanced by up to O(106) compared with the molecular conductivity of the fluid. Also, the mixing quality for specific mass exchange conditions has enhanced up to160% compared with the perfect mixing case.

Heterogeneous nucleation in citrate synthesis of AgNPs: Effect of mixing and solvation dynamics

The heterogeneity issues in silver nanoparticle nucleation (Lee-Meisel route) have been investigated. The final polydispersity and sphericity of the nanoparticles in the Lee-Meisel scheme are shown to depend upon the early time dynamics of silver-citrate complexation. The formation of macromolecular intermediary complexes in the early stages of the reaction is visualized based on online DLS data, TEM analysis, and the mass balances of silver and citrate ions. The reversible complexation between citrate ions and silver citrate is shown to be the limiting step that governs the directional growth of the nanoparticles. The dynamics of the complexation of citrate are seen to form a very rapid step and intense mixing was required for the complexation to happen uniformly across the reaction. This specific observation is also confirmed from the MD simulations. Thus, to get particles of high sphericity, irrespective of the reaction concentration, temperature, or reactor geometry, the mixing time should be <4 s and Da ~ 0.1. Optimal mixing conditions for isotropic growth are suggested based on the reaction kinetics and are also demonstrated with experimental evidence.

Investigating the Aluminothermic Process for Producing Ferrotitanium Alloy from Ilmenite Concentrate

The aluminothermic process is used for producing ferrotitanium alloy (FeTi) from an ilmenite concentrate. In this study, based on thermodynamic calculations and experiments, we investigated the effects of adding varying amounts of exothermal agent (NaClO3), slag-forming agent (CaO), and reducing agent (Al) on the recovery ratio of Ti in the aluminothermic process. The thermodynamic calculations suggested that the exothermal agent plays a crucial role in producing the FeTi alloy from the ilmenite concentrate and the maximum Ti grade in the FeTi alloy was approximately 30 wt %. Experimentally, it was verified that the FeTi alloy obtained under the optimum mixing conditions contained 30.2–30.8 wt % Ti, 1.1–1.3 wt % Si, 9.5–11.2 wt % Al, and 56.9–58.0 wt % Fe, along with trace impurities and small amounts of gases such as oxygen (0.35–0.66 wt %) and nitrogen (0.01–0.02 wt %). At the optimum mixing conditions, the recovery ratio of Ti into the obtained FeTi alloy phase was 60.6–68.9%. These results matched closely with the thermodynamic calculations. Therefore, the thermodynamic calculations performed herein are expected to significantly contribute toward the development of new processes and improvement in conventional processes for producing various ferroalloys including the FeTi alloy through the aluminothermic process.

Strength Characteristics of Controlled Low-Strength Materials with Waste Paper Sludge Ash (WPSA) for Prevention of Sewage Pipe Damage.

In this study, the effects of the mixing conditions of waste paper sludge ash (WPSA) on the strength and bearing capacity of controlled low-strength material (CLSM) were evaluated, and the optimal mixing conditions were used to evaluate the strength characteristics of CLSM with recyclable WPSA. The strength and bearing capacity of CLSM with WPSA were evaluated using unconfined compressive strength tests and plate bearing tests, respectively. The unconfined compressive strength test results show that the optimal mixing conditions for securing 0.8–1.2 MPa of target strength under 5% of cement content conditions can be obtained when both WPSA and fly ash are used. This is because WPSA and fly ash, which act as binders, have a significant impact on overall strength when the cement content is low. The bearing capacity of weathered soil increased from 550 to 575 kPa over time, and CLSM with WPSA increased significantly, from 560 to 730 kPa. This means that the bearing capacity of CLSM with WPSA was 2.0% higher than that of weathered soil immediately after construction; furthermore, it was 27% higher at 60 days of age. In addition, the allowable bearing capacity of CLSM corresponding to the optimal mixing conditions was evaluated, and it was found that this value increased by 30.4% until 60 days of age. This increase rate was 6.7 times larger than that of weathered soil (4.5%). Therefore, based on the allowable bearing capacity calculation results, CLSM with WPSA was applied as a sewage pipe backfill material. It was found that CLSM with WPSA performed better as backfill and was more stable than soil immediately after construction. The results of this study confirm that CLSM with WPSA can be utilized as sewage pipe backfill material.