Strength Of Agglomerates Research Articles

Particle agglomeration via resonant acoustic mixer for dry powder inhalation

The work presented in this paper employed a resonant acoustic mixing (RAM) process to optimize the fine particle agglomeration process for dry powder inhalation to achieve efficient pulmonary delivery of melatonin. The formulation prepared by acoustic mixing with the double layer grids demonstrated superior agglomerate particle size distribution and approximately 90% of the metered dose in the dosing chamber was emitted from Turbuhaler® (90% emitted dose). Acceleration force during acoustic mixing significantly affected the packing fraction of mixtures and mechanical strength of agglomerates resulting in improved fine particle fraction. The particle agglomeration via RAM can improve the efficiency of agglomerate production by utilizing the internal space of the mixer to induce more particle collision. The agglomerates formulation exhibited ideal fine particle fraction of 47.65 ± 1.46% and 56.02 ± 2.55% at flow rates of 30 and 60 L/min, respectively. The fine particle deposition was only slightly affected at the lower air-flow rate, suggesting a reliable inhalation performance in vivo.

Microplastic removal from water using modified maifanite with rotating magnetic field affected

Magnetic separation of microplastics from water is a new generation technology that is cost effective and environmentally friendly, and can avoid secondary pollution. The influence of magnetic Maifanite on polystyrene removal from water was investigated under a magnetic field action time, solution pH, magnetic carrier dosage, and polystyrene concentration, using a developed rotating magnetic field generator. Additionally, the polystyrene removal mechanism by the rotating magnetic field was revealed based on characterization and process simulation. The results showed that Maifanite can increase the number of surface adsorption sites and improve the adsorption performance after high temperature and acid impregnated modification. Specifically, the surface morphology of the modified Maifanite exhibited skirted stripes and a multilayered pore structure. And the specific surface area increased from 3.26 to 20.83 m2/g. The removal process is based on chemical adsorption, supplemented by physical adsorption. The magnetic carrier is tightly wrapped around the polystyrene surface by π bonds between the metal and hydroxy groups, ensuring agglomeration strength. Additionally, the rotating magnetic field generator designed can provide a rotating dynamic magnetic field, and the magnetic particles in the mixed system present a multi-directional helical motion trajectory, thus the walking displacement increases and the capture time decreases. And the probability of collision with non-magnetic particles and the formation of magnetic agglomerates are greatly increased. Thus the adsorption and removal of microplastics are enhanced theoretically. The polystyrene removal efficiency from water using modified Maifanite by rotating magnetic field affected increased by 19.49 %, reaching 98.46 %, and stabilizing at 86.53 % over 25 operation cycles. This study holds promise for advancing magnetic separation technology for microplastics from water.

Precise particle size control during spherical agglomeration of benzoic acid by modification of the bridging liquid phase using TWEEN 20

The interest in spherical agglomeration processes in the pharmaceutical industry is rising due to the possibility of direct tableting of Active Pharmaceutical Ingredients and enhancements in bulk powder properties translating into improved powder processability. While agglomerating needle-shaped particles into spheres offers numerous advantages, such as improved flowability, filterability, and particle density, achieving precise control over the particle size and shape of the agglomerates remains a significant challenge. More specifically, the obtained agglomerate size rarely reaches values below 500 μm, which is the desired size range for pharmaceutical applications. To address this challenge, the current research investigates the effectiveness of incorporating surfactants at varying concentrations as a means to control the particle size and shape of the resulting agglomerates. Reversed addition antisolvent crystallization experiments were performed in ethanol/water using benzoic acid as a model compound, followed by the addition of a bridging liquid (toluene), which wets and bridges the single crystals into agglomerates. To modify the interfacial tension between the two immiscible liquid phases, different concentrations of the tween 20 surfactant were used, leading to a range of interfacial tensions spanning from 0.50 to 16.38 × 10−3 N/m. Both crystallization and agglomeration processes were monitored in situ using in-process microscopy tools. The experimental results demonstrated that by adjusting the surfactant concentration and thus the corresponding interfacial tension of the bridging liquid, highly tunable agglomerate sizes were achieved, ranging from 160 μm to 4412 μm. A higher surfactant concentration is correlated with smaller agglomerates and is key to control the final agglomerate size. However, it should be noted that the introduction of surfactants in the spherical agglomeration process negatively impacted the agglomerate's strength. Nonetheless, this method remains a promising and innovative technique for controlling the final particle size during spherical agglomeration.

Implicit modelling of complex particulate structures: The effect of particle packing on agglomerate strength

Understanding the mechanical behaviors of agglomerate structures is significant in the powder industry for various applications. In this paper, we used a novel Implicit Modelling method to create complex agglomerate structures with controlled structural parameters. Our focus is on the effect of particle packing on the mechanical property of agglomerates by designing two sets of agglomerate structures: random and segregated ones based on primary particle sizes. We used 3D printing to manufacture the agglomerate structures into multiple copies. Through static compression and Finite Element Analysis (FEA), the random agglomerates exhibited overall higher mechanical strength than the segregated ones with the same porosity level. The experimental and numerical methods showed a consistent quantitative analysis of different mechanical property indicators of pre-designed agglomerate structures. Meanwhile, the relationship between different structural parameters and their respective mechanical properties were developed. The results help broaden our understanding of the complex influential factors governing agglomerate strength.

Micromechanics and strength of agglomerates produced by spray drying

Micromechanics and strength of agglomerates produced by spray drying

Fused silica with sub‐angstrom roughness and minimal surface defects polished by ultrafine nano‐CeO2

AbstractSurface quality of fused silica, particularly surface defect and surface roughness, is a key factor affecting the performance of high‐power laser and short‐wave optical instrument, and so on. Herein, the super smooth surface of fused silica with roughness of sub‐angstrom level and exceedingly few submicron defects was achieved by using ultrafine nano‐CeO2 with primary particle size less than 4 nm, low secondary particle agglomeration strength, and high Ce3+ concentration. Furthermore, CeO2 involve in polishing process in the form of primary particle was certified by experiment. Moreover, the cause for the generation of submicron defects on fused silica surface was investigated for the first time from the perspective of secondary particle agglomeration strength of CeO2. The concentration of Ce3+ in CeO2 was characterized by the redshift of the band‐gap energy, and the analysis of material removal rate (MRR) and contact angle of polished fused silica shows that Ce3+ enhances MRR through increasing the silanol group on fused silica.

A method for increasing the agglomerate strength by improving the charge pelletization

Since 2016 to the present, JSC Tulachermet has been systematically working to improve the quality of the iron ore part of the blast-furnace charge, which consists of at least 75% of the sinter of its own production. Within the framework of the article, research work was carried out on the selection and application of a line of technological additives for preparing sinter charge for sintering. The article describes the experience of using polymeric binders in laboratory and industrial conditions of sinter production, presents the results of the influence of various organizational and technical measures on the performance of sintering and blast furnace processes of JSC Tulachermet.

Reinforcement of Pellet Consolidation Strength Based on Iron Filings: Microstructural Evolution and Mechanism

In order to study the effect of adding finely ground iron filings as iron-based solid wastes to the pellets’ raw materials on the consolidation strength of pellets, this article uses scanning electron microscopy (SEM) and an image recognition system to identify the microstructure inside iron ore agglomerates, including grain size and porosity. Compressive strength measurements are carried out to quantitatively characterize the consolidation strength of agglomerates. The results demonstrate that when the proportion of iron filings increases, the proportion of particles above 6000 px2 in samples increases from 12.35% to 25.00%, and the internal porosity of agglomerates drops from 22.44% to 10.57%. The compressive strength of agglomerates increases from 2934.00 to 3712.50 N when the particle size of iron filings decreases. The compressive strength of agglomerates increases as preheating temperature drops at the same roasting temperature. When the preheating system is the same, the compressive strength of agglomerates increases as the roasting temperature rises. By adding low-oxidation iron filings to pellets, Fe2O3 generated through the preheating process has a high chemical reaction activity, allowing the oxidation to be completed at a lower preheating temperature and promoting the crystal bonding of Fe2O3 to form solid-phase consolidation with high compressive strength.

Particle Agglomeration of Acid-Modified Tapioca Starches: Characterization and Use as Direct Compression Fillers in Tablets.

Acid-modified tapioca starches (AMTSs) possessed good compressibility but showed poor particle flowability for preparing tablets by the direct compression method. The aims of this work were to prepare and characterize AMTS agglomerates using polyvinylpyrrolidone (PVP) as an agglomerating agent. The dilution potential and stability studies of the AMTS agglomerates were investigated. The results showed that particle enlargement of TS and AMTS could be achieved via agglomeration using PVP. The thermal behavior and molecular interaction of the agglomerates were revealed using DSC and FTIR spectroscopy, respectively. An increase in PVP concentrations resulted in greater particle strength of the TS agglomerates and a higher acid concentration for modification enhanced the strength of the AMTS agglomerates. All agglomerates presented good particle flowability. Moreover, the AMTS agglomerates provided higher compressibility hardness than the TS agglomerates. The addition of PVP could extend the disintegration time and slow drug dissolution from the agglomerate tablets. The humidity of the storage conditions influenced the thickness and hardness of the AMTS agglomerate tablets, and good physical and chemical stability of the tablets was obtained under ambient conditions and in the refrigerator. Furthermore, the AMTS agglomerates displayed good carrying capacity and possessed desirable characteristics for use in direct compression tablets.

DEM simulations of agglomerates impact breakage using Timoshenko beam bond model

Attrition and breakage of agglomerates are prevalent during production and handling processes in many industries. Therefore, it is highly desirable to be able to model and analyse the agglomerate breakage process under various loading conditions. The ensemble strength and breakage patterns of agglomerates are still not well understood despite a significant amount of research being carried out. In this study, three-dimensional discrete element method (DEM) simulation of the impact breakage behaviour of agglomerates were performed using a Timoshenko beam bond model which considers axial, shear, twisting and bending behaviours on the bonds. An advantage of the Timoshenko beam bond model is the pertinent parameters of the bond contact have clear physical meaning and therefore could be determined through corresponding experimental characterisations. The mechanical properties of the bonds in this study were firstly calibrated using experimental measurements. The validation of the Timoshenko beam bond model was then undertaken by direct comparisons between the numerical simulation and experimental results of impact tests. It was shown that the time evolution of the agglomerate breakage process obtained from simulation had good agreement with experimental observations. Numerical results indicate that most of the damage happens at the early stage of the impact and a cone shape fracture zone is formed quickly inside the agglomerate where strong compressive stresses are concentrated. It is found that the exterior of the fracture zone is surrounded by an arch shape tensile stress which dominates the fracture propagation.

Effects of lightweight particle content on the mechanical strength of cylindrical aggregates


 
 
 
 By using an extensive three-dimensional discrete element method, we numerically investigate the effects of lightweight particle content on the mechanical strength of the cylindrical aggregates, randomly composed of two different groups of primary particles: light (low stiffness) and heavy (high stiffness), and the stress contribution of the heavy-heavy, light-heavy, and light-light interactions on the mechanical behavior of such aggregates, subjected to the compression test by using a constant downward velocity. The interactions between primary particles are modeled by using the frictional-contact force law with a giving approximate analytical expression of capillary cohesion forces. We found that the lightweight particle content significantly affects the mechanical stress of aggregates and stress contribution obtained by different interaction types above, and the stress obtained by heavy-heavy interactions strongly dominates the mechanical strength of agglomerates. Remarkably, meanwhile, the stress obtained by the heavy-heavy contacts gradually decreases with increasing the lightweight particle content up to 20%, leading to the decrease of the mechanical strength, the stresses obtained by light-light and light-heavy contacts increase gradually. For higher lightweight particle contents, the results continuously show the same tendencies but with lower rates.
 
 
 

POTENTIAL AGGLOMERATION OF SMALL FOOD INDUSTRY IN PALEMBANG, SOUTH SUMATRA INDONESIA

The pattern of the spread of small food industries in Palembang show has led to the establishment of concentration patterns or clusters. This is evident from the grouping type of food industries in certain regions of the city of Palembang. The pattern of industrial activity concentration is spatially often identified with the agglomeration. It is, therefore, necessary to study the level of concentration and agglomeration force for small food industries. The population in this study was small food industries scattered throughout the districts in the city of Palembang. The analytical tool used Herfindahl index, locational Gini index, and the Agglomeration Strength Index. The results showed industrial concentration is highest in the district food Ilir Timur II at 1.4177 with labor contribution of 4.75 percent. Rated power at small industrial agglomeration in Palembang foods obtained at 0.03042, with a specialization level of 0.03036. Overall there are 488 units of small food industry businesses in Palembang and 21.7 percent are in the district of East Ilir II predominantly small soft drink industry with a total production amounting to Rp. 11,779,574. This suggests that small soft drink industry potential for development because it has a fairly wide market prospect and raw materials are relatively easy to obtain, although the potential for agglomeration is still relatively weak. Therefore, developing soft drink industry needs to consider the use of a cluster-based industrial strategy which is based on industry specialization driven by the occurrence of agglomeration in an effort to develop a competitive advantage in the face of competition in the free market era.Keywords: Spatial Concentration, Agglomeration, Herfindahl index, locational Gini index, Agglomeration Strength IndexJEL Classification: L66DOI: https://doi.org/10.32479/ijefi.11300

Increase in strength of manganese agglomerate during processing humate solution

The object of the research is the metallurgical technology of involving finely dispersed manganese concentrates, which are formed during the extraction and enrichment of raw materials, in the production of manganese agglomerate. The purpose of the work is to develop innovative technological solutions and recommendations for the sintering tec hnology of agglomerate with an increased up to 60% share in the charge of grade 2 finely dispersed concentrate based on the results of the analysis of physicochemical processes during the sintering of manganese agglomerate and experimental studies. Research methods – theoretical studies of concentrate agglomeration processes are based on the basic principles of physical chemistry and the theory of metallurgical processes. Calculations of the thermodynamic equilibrium of oxide systems, adequate for agglomeration, are based on the Gibbs theory and implemented using the computer program "FASTSage 6.0"; the method of mathematical statistics was used to process the results. Research results. A rational scheme for preliminary preparation of finely dispersed manganese ore enrichment waste for use in metallurgical processes has been determined; a rational amount of manganese ore beneficiation waste in the initial charge has been established; the proven possibility of returning 50...70% (against the usual 10...15%) of finely di spersed (0-1 mm fractions) grade 2 manganese concentrate to the batch for the production of manganese agglomerate due to the use of the peat hydroxide reagent (PTH) in the amount of 5...7% with a simultaneous increase the strength of the agglomerate granules is doubled. The original carbonate manganese ore was treated at the stage of dosing it into the batch and the obtained agglomerate with humic peat extract to strengthen the agglomerate and reduce dust formation

Scaling behavior of the tensile strength of viscocohesive granular aggregates

We numerically analyze the tensile strength of a single wet agglomerate modeled as a viscocohesive aggregate impacting a flat surface by using the discrete-element simulations. The viscocohesive agglomerate composed of primary spherical particles with the inclusion of the interstitial liquid in the form of the capillary bridges characterized by the cohesive and viscous forces between particles is extracted from a cuboidal sample of granular materials by applying a spherical probe. The tensile strength is measured from the impact test of a wet agglomerate by systematically varying different values of the surface tension of the interstitial liquid, the liquid viscosity, and the impact speed. We show that the tensile stress increases immediately when the collision occurs between the agglomerate and the flat surface. The peak of the tensile stress obtained after the collision, then decreases smoothly with increasing the particle movement. The maximum tensile stress is defined to be the tensile strength of such agglomerate. It is remarkable that the normalized tensile strength of such agglomerate can be well described as a function of a dimensionless impact number that incorporates the capillary number and Stokes number (calculated from the surface tension and the viscosity of the liquid and the impact rate of the agglomerate), thus providing the confirmation for the unified representation of the liquid properties and the impact rate of wet granular media.

Technological parameters determining the sintering process intensity

The sintering intensity is an important factor determining techno-economic efficiency of sinter production which provides the blast-furnace process with the main type of agglomerated iron ore raw materials. The charge sintering rate depends on technological parameters of the sintering process. Therefore, a systematic study of sintering technological parameters, which determine its intensity, is of practical and scientific interest. Indicators of the sintering process intensity are considered that assess it from both the mechanical and heat engineering positions. It is shown that in its purest form the sintering process intensity is characterized by the vertical agglomeration rate and combustion intensity of the sintering charge carbon. Two other indexes − the specific productivity for suitable sinter and intensity of heat output in the combustion zone – are less representative for the comparative estimation of sintering intensity, since their values depend on sintered mass strength and thermal effect of carbon combustion respectively. These factors go beyond the essence of the sintering intensity concept. Since content of fines of 5 – 0 mm at different sinter plants is not equal, representative performance comparison of sintering process is possible only taking into account the total amount of fines generated throughout the agglomerate transport path from sinter machine to blast furnace or the results of testing the agglomerate strength in a drum. A comprehensive systematic classification of techniques has been developed to intensify the sintering process based on the material-component principle using four levels of separation – objects, directions, paths and methods in which each subsequent level concretizes and develops the previous one. Its value is universality, which makes it possible to apply a systematization and separation system for almost all already known and future methods of sintering process intensification.

The Effect of Binder Loading on the Pore Size of 3D Printed PMMA.

Binder jetting is known to produce porous objects by depositing the binder selectively layer by layer on a powder bed. In this study, the pore size of printed parts and the correlating mechanical properties are investigated on a commercially available PMMA powder binder system. Pore sizes are measured via capillary flow porometry and mechanical properties via tensile tests. Porometry indicates that the pore size stays at a constant level of 22 µm at 5 to 10 wt% binder loading before decreasing to 6 µm at loadings of 30 wt% or higher. The results were compared with the mechanical testing and related to the agglomerate strength model of Rumpf. The highlights of the article are the application of a binder jetted part as a filter and the identification of a close relationship between porosity and mechanical strength, similar to phenomena in agglomeration science.

Impact of powder-binder interactions on 3D printability of pharmaceutical tablets using drop test methodology

In this study, a pre-screening test has been developed for the binder-jet 3D printing process (BJ3DP) which has been validated using statistical analysis. The pre-screening test or drop test has been adapted from the wet granulation field and modified later on to be used for tablet manufacturing in BJ3DP. Initially, a total of eight powders and ten water-based binder solutions have been introduced in the preliminary test to understand the powder-binder interactions. Afterward, based on the preliminary test results, three blends were developed which had undergone the same drop test. All these powder and binder combinations were then used for 3D printing. The key parameters such as mechanical strength and shape factors of the drop test agglomerates and 3D printed tablets were then compared using multiple linear regressions. Few dimensionless parameters were introduced in this study such as binding capacity and binding index to capture the printability properties of the powders used in this study.Significant relations (p<0.05) were found between the drop test and the BJ3DP process. Application of drop test was carried out to establish a prescreening test, ii) to develop new blend formulations as well as iii) to develop a fundamental understanding of powder-binder interaction during BJ3DP process

Biosilicated collagen/\u03b2-tricalcium phosphate composites as a BMP-2-delivering bone\u2010graft substitute for accelerated craniofacial bone regeneration

BackgroundBioceramic β-tricalcium phosphate (β-TCP) is used as a bone-grafting material and a therapeutic drug carrier for treatment of bone defects in the oral and maxillofacial regions due to the osteoconductivity and biocompatibility. However, the low mechanical strength and limited osteoinductivity of β-TCP agglomerate restrict bone regenerating performance in clinical settings.MethodsHerein, a biomimetic composite is proposed as a bone morphogenetic protein-2 (BMP-2)-delivering bone graft substitute to achieve a robust bone grafting and augmented bone regeneration.ResultsThe sequential processes of brown algae-inspired biosilicification and collagen coating on the surface of β-TCP enable the effective incorporation of BMP-2 into the coating layer without losing its bioactivity. The sustained delivery of BMP-2 from the biosilicated collagen and β-TCP composites promoted in vitro osteogenic behaviors of pre-osteoblasts and remarkedly accelerated in vivo bone regeneration within a rat calvarial bone defect.ConclusionsOur multicomposite bone substitutes can be practically applied to improve bone tissue growth in bone grafting applications with further expansion to general bone tissue engineering.

Dispersion of Graphite Nanoplates in Polypropylene by Melt Mixing: The Effects of Hydrodynamic Stresses and Residence Time.

This work combines experimental and numerical (computational fluid dynamics) data to better understand the kinetics of the dispersion of graphite nanoplates in a polypropylene melt, using a mixing device that consists of a series of stacked rings with an equal outer diameter and alternating larger and smaller inner diameters, thereby creating a series of converging/diverging flows. Numerical simulation of the flow assuming both inelastic and viscoelastic responses predicted the velocity, streamlines, flow type and shear and normal stress fields for the mixer. Experimental and computed data were combined to determine the trade-off between the local degree of dispersion of the PP/GnP nanocomposite, measured as area ratio, and the absolute average value of the hydrodynamic stresses multiplied by the local cumulative residence time. A strong quasi-linear relationship between the evolution of dispersion measured experimentally and the computational data was obtained. Theory was used to interpret experimental data, and the results obtained confirmed the hypotheses previously put forward by various authors that the dispersion of solid agglomerates requires not only sufficiently high hydrodynamic stresses, but also that these act during sufficient time. Based on these considerations, it was estimated that the cohesive strength of the GnP agglomerates is in the range of 5–50 kPa.

Textural Implications in Assessment of Physico-Mechanical behaviour of Metavolcanic Rocks from Dir Upper, north western Pakistan

The Dir-Utror meta-volcanics from the south western portion of the Kohistan arc in northern Pakistan areanalyzed in term of their petrography, physico-mechanical properties. Field observations and petrography show thecollected representative samples to be fine-grained meta-andesites (FMA), coarse-grained meta-andesites (CMA) andagglomerate (AG). The relationship between petrography and physico-mechanical properties has been investigatedwhich inferred the grain size to be the major factor, alongside grains’ shape, arrangement and size distribution as wellas degree of mineral alteration significantly affecting the mechanical behavior of rocks. The CMA yield more strength(98 MPa) than FMA (93 MPa) due to its lesser degree of mineral alteration, inequigranular texture, lack of preferredmineral alignment, relatively low porosity and water absorption. The lower strength of agglomerate (57 MPa)corresponds to abundance of soft minerals (calcite), exotic rock fragments and coarse-grained texture. Based onphysico-mechanical properties including specific gravity, bulk density, aggregate impact value, Los Angeles abrasionvalue and unconfined compressive strength (UCS), these rocks fall within permissible range to be utilized for multipleengineering purposes including dimension stones and foundation materials for other civil structures. However,petrographic investigations reveal excessive amount of reactive silica in these rocks making them prone to alkali-silicareactivity in concrete works with ordinary Portland cement (OPC). Hence these rocks are not recommended for use assole aggregate material or low-alkali cement is recommended, if used.