Solid Particle Size Research Articles

The Processing Space of the Spray-Dried Mannitol-Leucine System for Pulmonary Drug Delivery.

Designing spray-dried particles for inhalation aims at specific physicochemical properties including a respirable aerodynamic diameter and adequate powder dispersibility. Leucine, an amphiphilic amino acid, has been shown to aid in optimizing bulk powder properties. Mannitol, a model crystalline active and common bulking agent, was co-sprayed with leucine at several excipient ratios, ethanol/water ratios, and spray dryer outlet temperatures in order to experimentally probe the underlying particle formation mechanisms in this binary crystalline system. During the droplet drying of two crystallizing components, the material that nucleates first will preferentially enrich the surface. It is desired to have a completely crystalline leucine shell to improve powder properties, however, mannitol competes with leucine for the surface depending on excipient concentration and manufacturing parameters. The resulting particles were studied initially and at a two-month timepoint via solid state characterization, visual analysis, and particle size analysis in order to detect changes in bulk powder properties. It was determined that, similar to systems where only leucine can crystallize, initial leucine saturation in the formulation dictates powder characteristics.

Erosion Analysis and Optimal Design of Sand Resistant Pipe Fittings

Erosion of solid particles in a pipe elbow containing a 90° angle is investigated by simulation methods. In the process of shale gas exploitation, the impact of solid particles carried by fluid on the inner surface wall of pipes, as well as the turbulent flow, cause the erosion of pipes, which brings about heavy economic losses for the oil and gas industry. In the impact erosion of the inner surface wall of the pipe, the worst erosion occurs at the elbow. In this study, the erosion of a pipe elbow which has been widely used in actual production is analyzed, and the influence of the fluid velocity, the solid particle size, and the wall roughness on the erosion is investigated. Additionally, the simulation results of the erosion with the rebound and freeze boundary conditions are compared, indicating that setting the freeze boundary condition could significantly improve the computational efficiency by 74% with the acceptable accuracy. In order to reduce the impact erosion in the pipe elbow containing a 90° angle, an optimal design is proposed that can reduce the maximum erosion rate by 52.4%. These results complement the research of elbow erosion and provide ideas for the optimization problem of a pipe elbow containing a 90° angle.

Preparation of Samples for the Study of Rheological Parameters of Digested Pulps in a Bioreactor of an Agricultural Biogas Plant

The studies of the rheology of digested pulp from agricultural biogas plants have often been fragmentary and non-standardised due to their complexity and time-consuming nature. As a result of measurements, it was possible to develop a procedure and range of measurements for the correct determination of the parameters of the carrier substance. The applicability of the coaxial cylinder measurement system was demonstrated for assessing the rheological parameters of digested pulp from a fermenter that utilises agricultural biomass. To determine the characteristics of solid particles, the Zingg diagram was used, inter alia, allowing the comparison of particles from each fraction. The analysis of the shape and size of solid particles may help to describe the onset of motion of this phase, flow type, or sedimentation type. The authors propose a completely new research approach to obtain an appropriate, repeatable test conditions of medium, which is the carrier liquid from the biogas plant reactor. The proposed methodology and the scenario of the entire study make it possible to achieve scalable and comparable test results in any laboratory. The proposed solution eliminates the influence of most external factors on the sample and rheological measurements, and the effectiveness of the presented procedure was confirmed in tests.

The erosion rate prediction for the elbow in shale gas gathering and transportation system: RSM and GA-BP-ANN modeling

Elbow erosion caused by sand mixed in shale gas is a significant issue faced by shale gas gathering and transportation systems, posing a serious threat to the safe and stable production of shale gas. In this paper, the factors affecting elbow erosion in the shale gas gathering and transportation system are identified. The computational fluid dynamics (CFD) two-way coupling Euler-Lagrange method is used to investigate the single-action of various parameters on particle trajectory, erosion morphology, and maximum erosion rate, including pipe inner diameter, pipe R/D ratio, pipe bending angle, pipe bending orientation, solid particle velocity, solid particle size, and solid particle mass flow rate. Subsequently, the response surface methodology (RSM) is employed to quantitatively explore the synergistic interactions between these factors that affect the maximum erosion rate of the elbow, and a surrogate model for simple and rapid evaluation of the maximum erosion rate for elbows at the engineering level is proposed. Finally, the backpropagation artificial neural network (BP-ANN) optimized by genetic algorithm (GA) is used to train the samples obtained by Latin hypercube sampling (LHS) in the multi-factor range. By comparison, the RSM surrogate model and the GA-BP-ANN model reveal a favorable level of agreement with the experimental data, while considering various influential factors. It is important to note that each method possesses distinct advantages, limitations, and specific application environments. This research can provide quantitative references for preventing and controlling erosion within the shale gas gathering and transportation system.

Semi-batch extraction of phenolic compounds from Rosmarinus officinalis: Kinetic study and dimensionless modeling

A transient and one-dimensional mathematical model with two partial differential equations is developed to simulate the extraction of de-oiled rosemary plant in a vertical fixed-bed reactor. The effect of the dimensionless numbers which appear in the final governing equations (Peclet and Damköhler numbers) is studied. The influence of solvent composition, solid particle size and temperature is also investigated. The process is controlled by internal diffusion effects, with the smallest particle size exhibiting the smallest internal diffusion coefficient. Among the different solvents, 80% ethanol shows the highest total phenolics recovery. The antiradical activity is also enhanced by increasing the temperature and the smaller particle size leads to an improvement in the extraction selectivity. Peclet number has a small effect on the results, while Damköhler number strongly affects the process. An increase in bed porosity causes a significant increase in the internal diffusion time.

Effect of Inserting Baffles on the Solid Particle Segregation Behavior in Fluidized Bed Reactor: A Computational Study

In multi-solid, particle-size fluidized bed reactor systems, segregation is commonly observed. When segregation occurred, small solid particles were entrained to the top of the bed and escaped from the reactor. During the combustion process, the small solid particles that escaped from the boiler were burned and subjected to damage around the cyclone separator. This study then employed a computational fluid dynamics approach to investigate solid particle behavior in the reactor using three different sizes of solid particles. The effects of baffle insertion, baffle angle, stage number, and its arrangement were examined. The percentage of segregation was calculated to compare behavior among different reactor systems. The insertion of 45-degree baffles resulted in reduced segregation behavior compared to cases without baffles and with 90-degree baffles, attributed to solid hindering and collision phenomena. Additionally, a double-stage baffle with any arrangement could reduce segregation behavior. The best arrangement was “above-arrangement” due to particles hindering, swirling, and accumulating between the baffle stages. Therefore, to diminish segregation behavior and enhance combustion chemical reactions, the insertion of baffles in the reactor zone is recommended.

Acoustofluidics-Assisted Multifunctional Paper-Based Analytical Devices.

Microfluidic paper-based analytical devices (μPADs) feature an economic and sensitive nature, while acoustofluidics displays contactless and versatile virtue, and both of them gained tremendous interest in the past decades. Integrating μPADs with acoustofluidic techniques provides great potential to overcome the inherent shortcomings and make appealing achievements. Here, we present acoustofluidics-assisted multifunctional paper-based analytical devices that leverage bulk acoustic waves to realize multiple applications on paper substrates, including uniform colorimetric detection, microparticle/cell enrichment, fluorescence amplification, homogeneous mixing, and nanomaterial synthesis. The glucose detection in the range of 5-15 mM was conducted to perform uniform colorimetric detection. Various types (brass powder, copper powder, diamond powder, and yeast cells) and sizes (5-200 μm) of solid particles and biological cells can be enriched on paper in a few seconds or minutes; thus, fluorescence amplification by 3 times was realized with the enrichment. The high-throughput and homogeneous mixing of two fluids can be achieved, and based on the mixing, nanomaterials (ZnO nanosheets) were synthesized on paper. We analyzed the underlying mechanisms of these applications in the devices, which are attributed to Faraday waves and Chladni patterns. With their simple fabrication and prominent effectiveness, the devices open up new possibilities for paper-based microfluidic devices.

Advance review on occurrence state and leaching of lithium in sedimentary bauxite (aluminum) deposits, China

Bauxite-associated type Li resource is mainly discovered in the sedimentary bauxite (aluminum) deposits forming areas, especially Northern Guizhou-Southern Chongqing, Western Henan and Central Guizhou, China. This paper reviews the enrichment mechanism and occurrence states of Li in sedimentary bauxite (aluminum) deposits. The Li in these deposits is derived from underlying carbonate rock, and the favorable sedimentary environment, e.g., alternation climate of dry and humid, the marine-continental transitional zone with reduction-weak oxidation and low salinity, is conducive to the Li enrichment in these deposits. Li is mainly hosted by independent mineral (i.e., cookeite), partly adsorbed by montmorillonite, and rarely adsorbed by illite/kaolinite. Furthermore, the leaching methods and affecting factors of Li from bauxite-associated type Li resource are summarized. Acid solution is the main leaching solution, but its excessive use can generate abundant acidic residues, which have hazards to the environment. Thereby, leaching solution with little or no acid has been recommended. The affecting factors of Li leaching are the calcination temperature, leaching temperature, leaching time, liquid–solid ration and mineral particle size. The above summary deepens the understanding of the enrichment mechanism and occurrence states of Li in the sedimentary bauxite (aluminum) deposits, and has the potential to promote Li resource, initially considered uneconomical, become an important economic source of Li.

A clean and efficient route for extraction of vanadium from vanadium slag by electro-oxidation combined with ultrasound cavitation

Extracting vanadium (V) from vanadium slag (VS) by the traditional roasting-leaching process has disadvantages of high energy consumption and high poisonous gases emission. In this work, a green and efficient route was developed to extract V from VS without roasting by electro-oxidation combined with ultrasound cavitation (EOUC) intensification in sulfuric acid solution. The leaching parameters (e.g., leaching temperature, sulfuric acid concentration, anodic current density, ultrasound power, liquid to solid ratio, leaching time and particle size) were optimized. The leaching mechanism was explored by comparing the leaching behavior and mineralogical evolution of the direct sulfuric acidic leaching (DSL), electro-oxidation-assisted sulfuric acidic leaching (EOSL), ultrasound cavitation-assisted sulfuric acidic leaching (UCSL) and EOUC methods. The results show that introducing electric field strengthens the ultrasound cavitation effect on slag particles in sulfuric acid solution. Under the optimum parameter of EOUC method, the leaching rate of V from VS is as high as 94.64 %. Using EOUC method can open the silicate-wrapped structure of the spinel, increase pore volume of VS from 0.00127 cm3 g−1 to 0.01124 cm3 g−1, decrease slag particle size from 26.8 μm to 16.4 μm and improve specific surface area from 0.508 m2 g−1 to 10.855 m2 g−1, which significantly accelerate V leaching process. The exposed spinel was oxidized by both electrochemical route and chemical route, forming a mixture of V3+ ion and VO2+ ion after leaching.

Effects of varied building solid wastes, particle sizes and substitution ratios on the performance and impedance spectrum of recycled fine aggregate mortar and the feasibility of developing a prediction method

In this study, three solid waste materials (sintered bricks (SB), aerated blocks (AB) and cementitious mortar (CM)) were studied to analysis the influence on the impedance characteristics and mechanical properties of recycled sand mortar. Mortar containing recycled sand obtained similar or even higher compressive strengths as to the control group at 15% substitution rate. The density of the mortar decreased with the substitution rate of recycled sand. The porosity increased by 18% compared to the control group with an inclusion of 45% of SB. The bulk density of recycled mortar was found to be related to the particle size of the recycled sand, for instance, the bulk density of ABCS45 was 6% less than ABFS45. The AC impedance spectrum results showed that the high-frequency arc was the smallest for AB and the largest for CM. The R1 values of AB were 0.27 and 0.14 times that of SB and CM, respectively. The high-frequency arc of the mortar increased with hydration, consuming OH− ions and raising R0 values, while the compacting matrix led to a rise in R1 values. After 28 days curing, mortars containing SB and CM sands displayed higher R1 values, with CMCS45 being approximately 50% higher than the control group. Through analyzing the physical, mechanical, and impedance properties, it revealed a correlation coefficient −0.88 between porosity and R0 values, with bulk density and compressive strength demonstrating stronger correlation with R1 values. These findings offer valuable guidance for utilizing and nondestructively testing recycled materials.

Salting-out effect-mediated size-control of protein nanoparticles towards controllable microstructures for sustained release of eugenol

Size and monodispersity of solid particles are essential to their structuring behaviors at biphasic interfaces. However, delicate control over biomolecular nanoparticle sizes is challenging. In this study, we prepared monodisperse rice protein (RP) nanoparticles by neutralizing RP solutions (pH 12.0) using combined treatments of cationic exchange resins (CERs) and HCl. CERs absorbed Na+ by releasing H+ without producing salt during neutralization. By compromising the usages of CERs and HCl when preparing RPs, the generation of NaCl can be delicately tailored, leading to controllable nanoparticle sizes from 20 nm to 30 nm. By mixing these nanoparticles with eugenol in an aqueous solution, the nanoparticles accommodated eugenol in their cores due to inward diffusion. Furthermore, such eugenol-contained nanoparticles with different sizes demonstrated tunable releases of eugenol due to size-dependent capillary forces, which can be harnessed for suppression of microbial growth on fruit with prolonged effective eugenol concentration.

The Impact of Restricting Air Intake in Self-Aspirated Flotation Cells at Los Pelambres Concentrator

This article describes the impact of restricting the air intake in industrial 250 m3 WEMCO flotation cells at Los Pelambres concentrator. The influence of air restriction on the hydrodynamic and metallurgical performance of this type of machine was evaluated. The experiments were conducted in single flotation cells and entire rougher banks. In all cases, the gas holdup was measured to estimate the effectiveness of the obstruction system to decrease the air concentration. In single cells, axial profiles for solid percentage and particle size were evaluated. In addition, mass balances were conducted to assess the copper recoveries and concentrate features. In individual cells, air restriction led to a decrease in the gas holdup. However, this slight change was enough to obtain a more stable froth zone and a better solid suspension. The latter was observed as: (i) a higher P80 below the pulp–froth interface, (ii) a less diluted pulp at this level, (iii) a slightly higher Cu recovery, and (iv) a coarser concentrate product. A mineralogical analysis of the concentrate sample also showed the presence of coarser liberated Cu-sulfide particles. The results in single cells suggested an improvement in the recovery of coarse particles via more intense solid suspension. The air intake was also restricted in three rougher banks to assess the impact of air obstruction on the overall performance of the respective circuit. Eleven out of fourteen cells were operated with air restriction, which led to a significant improvement in recovery of 0.9%–1.6% (absolute), at a 95% confidence level. Size-by-size mass balances were also conducted for the rougher circuits, which proved that the recovery improvements were justified by the simultaneous increase in the recovery of coarse and fine particles. Thus, a restriction in the air intake showed that a decrease in the gas holdup (and in the bubble surface area flux) was compensated by better solid suspension and a higher collision efficiency in the draft tube. The former promoted the recovery of coarse particles in the quiescent zone, whereas the latter improved the interaction between bubbles and fine particles. Further developments are being made to implement a regulatory control strategy for the air intake in self-aspirated flotation cells and to use this approach for optimizing industrial flotation banks.

Impact of the Solid Electrolyte Particle Size Distribution in Sulfide‐Based Solid‐State Battery Composites

AbstractAll solid‐state batteries are promising, as they are expected to offer increased energy density over conventional lithium‐ion batteries. Here, the microstructure of solid composite electrodes plays a crucial role in determining the characteristics of ionic and electronic pathways. Microstructural aspects that impede charge carrier transport can, for instance, be voids resulting from a general mismatch of particle sizes. Solid electrolyte materials with smaller particle size distribution represent a promising approach to limit the formation of voids and to match the smaller active materials. Therefore, a systematic investigation on the influence of the solid electrolyte particle size on the microstructural properties, charge carrier transport, and rate performance is essential. This study provides an understanding of the influence of the particle sizes of Li6PS5Cl on the charge carrier transport properties and their effect on the performance of solid‐state batteries. In conclusion, smaller Li6PS5Cl particles optimize the charge transport properties and offer a higher interface area with the active material, resulting in improved solid‐state battery performance.

Antimicrobial Activity of Frankincense (Boswellia sacra) Oil and Smoke against Pathogenic and Airborne Microbes.

As they continuously evolve, plants will remain a renewable source for antimicrobial compounds. Omani frankincense is produced by B. sacra trees and is graded into Hojari, Nejdi, Shazri or Sha'bi. Air can be a source for pathogenic or food spoilage microbes; thus, inactivating airborne microbes is necessary in environments such as food and animal production areas. This study investigated the antimicrobial activity and the chemistry of steam-distilled oils of Hojari and Sha'bi grades. It also analyzed the antimicrobial activity of frankincense smoke and the size of its solid particles. Chemical analysis was performed using gas chromatography mass spectrometry (GC-MS). The antimicrobial activity of the oils against Staphylococcus aureus (NCTC 6571), Bacillus spp., Escherichia coli (NCTC 10418), Pseudomonas aeruginosa (NCTC 10662), Saccharomyces cerevisiae, Candida albicans, Aspergillus flavus, Aspergillus ochraceus, Aspergillus niger, Penicillium citrinum, Alternaria alternata and Fusarium solani was determined using well diffusion and micro-well dilution methods. A microscopic technique was used to determine the size of frankincense smoke solid particles. Microbes were exposed to frankincense smoke to test their susceptibility to the smoke. Hojari and Sha'bi oils were similar in composition and contained monoterpenes and sesquiterpenes. The Hojari and the Sha'bi oils possessed broad spectrum antimicrobial activity. The largest growth inhibition zones were obtained with S. cerevisiae and F. solani. An MIC of 1.56% (v/v) was found with E. coli, S. cerevisiae and F. solani. Frankincense smoke contained fine irregular solid particles with a diameter range of 0.8-2287.4 µm, and thus may pose a health risk to susceptible individuals. The smoke had potent antimicrobial activity against S. aureus, E. coli, and airborne bacteria, yeast and mold, with a maximum inhibition of 100%. It was concluded that Hojari and Sha'bi frankincense oils and smoke had significant antimicrobial activity that can be exploited in controlling human, animal and plant pathogenic microbes.

Origins and Influences of Voids in Composite Cathodes for All-Solid-State Batteries

With the exit from fossil-fuel energy becoming more and more urgent, advanced batteries are highly sought after and all-solid-state batteries (ASSBs) are seen as a promising technology potentially enabling lithium metal or reservoir-free anode designs which promote the energy density.Despite high research interest in the field, ASSBs still perform below expectations, the main challenges being elevated interfacial resistances, microstructure effects and processing, particularly at large scale. While the build-up of high resistances due to void formation upon lithium stripping at the anode side is increasingly understood, the void formation and its evolution in the composite cathode as well as the effects on the cell performance are widely unknown.Why consider voids in the cathode at all?In contrast to conventional, liquid electrolytes, solid ion conductors (such as thiophosphates) do not easily infiltrate voids and cracks in the cathode1. They possess a proper particle morphology and, depending on the solid electrolyte particle size distribution, its suitability to the active material particle sizes and morphologies the electrode structure that forms upon manufacturing can be quite different and influences the ion and electron transport as well as the charge transfer capabilities2-5. Experimentally determined void fractions in the composite typically range from 3 to 40 vol%6,7 and are therefore far away from being negligible.Apart from the void formation at manufacturing, scanning electron microscope (SEM) cross sections of cycled composites have also shown that the volume changes of LiNixCoyMn(1-x-y)O2 active material can lead to contact loss at the interface of the solid electrolyte and the active material8 which reinforces the importance of understanding the origins and the influences of voids on the cell performance.In this talk, we will discuss these, mainly from the modeling perspective including percolation network models4, flux-based simulations of the effective conductivity5 and electrochemical charge simulations based on the finite-element method9. Additionally, we use focused ion beam(FIB)-SEM tomography for the reconstruction of cathodes with different microstructures obtained by changing the particle size of the solid electrolyte. We investigate the influence of the solid electrolyte particle size distribution on the void space fraction and distribution and provide guidelines for further cathode optimization. Ruess, R.; Schweidler, S.; Hemmelmann, H.; Conforto, G.; Bielefeld, A.; Weber, D. A.; Sann, J.; Elm, M. T.; Janek, J., J. Electrochem. , 2020, 167, 100532.Minnmann, P.; Quillman, L.; Burkhardt, S.; Richter, F. H.; Janek, J., Electrochem. Soc., 2021 , 168, 040537.Jiang, W.; Zhu, X.; Huang, R.; Zhao, S.; Fan, X.; Ling, M.; Liang, C.; Wang, L., Energy Mater, 2022 , 12, 2103473.Bielefeld, A.; Weber, D. A.; Janek, J., Phys. Chem. C, 2019 , 123, 1626-1634.Bielefeld, A.; Weber, D. A.; Janek, J., ACS Appl. Interfaces, 2020 , 12, 12821-12833.Shi, T.; Zhang, Y.-Q.; Tu, Q.; Wang, Y.; Scott, M. C.; Ceder, G., Mater. Chem. A, 2020 , 8, 17399-17404.Ates, T.; Keller, M.; Kulisch, J.; Adermann, T.; Passerini, S. Energy Storage Mater., 2019 , 17, 204-210.Koerver, R.; Aygün, I.; Leichtweiß, T.; Dietrich, C.; Zhang, W.; Binder, J. O.; Hartmann, P.; Zeier, W. G.; Janek, J., Mater., 2017 , 29, 5574-5582.Bielefeld, A.; Weber, D. A.; Ruess, R.; Glavas, V.; Janek, J., Electrochem. Soc., 2022 , 169, 020539. Figure 1

A modelling approach to investigate the performance of slurry bubble column reactors implementing Fischer–Tropsch synthesis

AbstractA reliable estimation of the reactor performance is a crucial aspect of slurry bubble column reactor design. Hydrodynamics, mass transfer, and reaction rate are the main parameters influencing the overall performance. A new hydrodynamic model was adopted in this study to properly predict the effect of solids loading, particle size, pressure, and temperature on the gas holdup, bubble size distribution, and mass transfer coefficient. The reactor was divided into small cells with individual hydrodynamic parameters. The results were compared with the experimental data and showed that the model can acceptably predict the hydrodynamic and mass transfer parameters in various process situations. A parametric study was accomplished to understand the effect of catalyst loading, superficial gas velocity, H2/CO ratio, L/D ratio, pressure, temperature, and catalyst attrition on the conversion rate, catalyst productivity, and space–time yield. A cobalt/silica catalyst was adopted in this study. Based on the obtained results, the syngas conversion increases by catalyst loading, L/D, and temperature, while it decreases by Ug and pressure. The H2/CO ratio results in a maximum conversion somewhere between 2 and 2.5. Three different scenarios were determined to study the effect of catalyst attrition on the reactor performance. The results show that the attrition decreases the syngas conversion due to the decrease in the catalyst size and the catalyst loss. Also, the performance remains constant if a sufficient amount of fresh catalyst is added to the system continuously.

Biogas upgrading through calcium looping: Experimental validation and study of CO2 capture

The calcium looping technology is one of the most promising technologies for capturing and storing CO2. This technology has been evaluated with a variety of sorbents and conditions in previous works, but the inlet CO2-ladden gas has typically been a flue gas from combustion, which typically has a composition of 10–20% CO2 and 80–90% N2. On the other side, the performance of the calcium looping process for CO2 capture of other gases (i.e., biogas or gases resulting from hydrothermal carbonization) remains largely unstudied. In this work, this knowledge gap is assessed through evaluating the performance of the calcium looping process for biogas (synthesized as 40% CO2, 60% CH4) in terms of carbonation conversion. This experimental study investigates the impact of: (1) using an inlet gas composition representative for biogas instead of combustion flue gas; (2) different biogas compositions; (3) the carbonation temperature; (4) the cooling-down and heating-up of the sorbent material between the reactor and ambient temperatures within cycles; (5) the atmosphere composition during calcination; and (6) the solids particle size. The main result obtained is that the overall CO2-capture performance of calcium looping improves when using biogas as inlet CO2-ladden gas, in comparison with combustion flue gas. One main contribution to this improved performance is shown to be the presence of secondary reactions (i.e., dry reforming, methanation). The impact of the CH4 to CO2 ratio tested is not remarkable, showing that the potentialities of the process in this aspect can be adapted to several biogas producing feedstocks.

Flow irreversibility versus wear of elbow-reducer connection with gas-solid two-phase flow: A numerical study via CFD-DEM coupling method

In industry sectors, such as power, petroleum, and natural gas production, many fluids contain solid particles in gas/liquid-solid two-phase flows. Thus, resistance and wall erosion, which mainly occur at pipe resistance components, such as elbows and reducers, should be considered in the design of conveying pipelines. To examine the interaction of two resistance components, the flow irreversibility versus wear of an elbow-reducer connection with a gas–solid two-phase flow were studied via the CFD–DEM coupling method. The studied connection structures include a reducer at the elbow downstream with distances of 0, 1, and 3 pipe diameters, and a reducer at the elbow upstream with distances of 0, 1, and 3 pipe diameters. Results show that turbulence and wall entropy generation are main reasons for the total entropy generation and flow irreversibility, which are mainly distributed in the interior wall of the elbow and the pipe. The reducer located downstream of the elbow has a good inhibition effect on the fluid with a separation phenomenon. The total entropy generation and maximum erosion rate for the elbow-reducer connections are lower than that for the reducer-elbow connections. Moreover, influences of solid particle mass flow rate and particle size on partial entropy generations, including mean, turbulent, and wall entropy generations, and wall erosion were comparatively analyzed. The simulation results can provide a reference for the design of pipelines to reduce energy consumption and pipeline wear.

Modeling of the Sintered Density in Cu-Al Alloy Using Machine Learning Approaches.

In powder metallurgy materials, sintered density in Cu-Al alloy plays a critical role in detecting mechanical properties. Experimental measurement of this property is costly and time-consuming. In this study, adaptive boosting decision tree, support vector regression, k-nearest neighbors, extreme gradient boosting, and four multilayer perceptron (MLP) models tuned by resilient backpropagation, Levenberg-Marquardt (LM), scaled conjugate gradient, and Bayesian regularization were employed for predicting powder densification through sintering. Yield strength, Young's modulus, volume variation caused by the phase transformation, hardness, liquid volume, liquidus temperature, the solubility ratio among the liquid phase and the solid phase, sintered temperature, solidus temperature, sintered atmosphere, holding time, compaction pressure, particle size, and specific shape factor were regarded as the input parameters of the suggested models. The cross plot, error distribution curve, and cumulative frequency diagram as graphical tools and average percent relative error (APRE), average absolute percent relative error (AAPRE), root mean square error (RMSE), standard deviation (SD), and coefficient of correlation (R) as the statistical evaluations were utilized to estimate the models' accuracy. All of the developed models were compared with preexisting approaches, and the results exhibited that the developed models in the present work are more precise and valid than the existing ones. The designed MLP-LM model was found to be the most precise approach with AAPRE = 1.292%, APRE = -0.032%, SD = 0.020, RMSE = 0.016, and R = 0.989. Lately, outlier detection was applied performing the leverage technique to detect the suspected data points. The outlier detection discovered that few points are located out of the applicability domain of the proposed MLP-LM model.

Population balance modeling of InP quantum dots: Experimentally enabled global optimization to identify unknown material parameters

Despite great progress in the synthetic chemistry of InP QDs, a predictive model to describe their temporal formation is still missing. In this work, we introduce a population balance model incorporating liquid phase reactions, homogeneous nucleation and reaction-limited growth of InP supported with the highly reproducible and reliable experimental data acquired from an automated robotic synthesis platform. A comparison between experimental kinetic data (different initial concentrations and temperatures) and simulations was made. The proposed model describes the temporal evolution of solid concentration, particle diameter and particle size distribution very well. The quantitative agreement between experiments and simulations was only achieved by global optimization to identify unknown and hardly measurable material parameters and kinetic constants such as surface energy, growth rate constants or activation energies. We see this model rendering the first step towards the development of more refined models that enable rigorous optimization and control of the production process for III-V semiconductors.