Optimum Particle Size Research Articles

Engineering electronic and geometric structures of Fe, N-doped carbon polyhedrons toward organic contaminant oxidation

A universal gas diffusion strategy was developed to derive highly efficient PMS-activation catalysts comprising isolated Fe atoms coordinated with N species embedded in carbon polyhedrons (Fe-NC). Their electronic and geometric structures were modulated by altering the precursor ratio and calcination temperature. Benefiting from the maximized atomic utilization, the obtained catalysts exhibited superior catalytic performances, outperforming almost all previously reported metal materials. The enhanced activity is likely due to an optimal particle size and Fe content, favorable Fe-Nx active sites, and conductive carbon materials. Scavenging and probing experiments indicated that surface Fe-NC and the defective edges with oxygen functional groups were the active sites for PMS activation to produce surface-bonding active complexes (Fe-NC-PMS) and high-valent iron oxo species (FeV = O) for organic degradation, unlike the reported radicals and singlet oxygen mediated degradation. Overall, this work provides a universal gas diffusion strategy to design dimension-controlled Fe-NC catalysts for the elimination of organic pollutants.

Aspen adsorption simulation on biosorption between water hyacinth (Eichhornia crassipes) and Pb (II) ions in packed bed column

Biosorption offers low capital and operating cost on removal of heavy metals from contaminated aqueous wastewater. This research study evaluated the effect of flow rates, initial concentration of Pb (II) ions, bed height and operating conditions of the continuous flow adsorption process on the breakthrough time of the bed column containing water hyacinth as biosorbent through simulation by using Aspen Adsorption. The simulation was conducted whereby the flow rates (Q) were varied between 0.2 L/s and 0.8 L/s, the initial concentration of Pb (II) ions (Co) were varied between 20 mg/L and 200 mg/L, and the bed height (h) were varied between 0.25m and 1.00 m. The objectives are achieved whereby, when Q decrease, Co decreases and the h increases, the breakthrough time increases. When Q is 0.2 L/s, Co is 20 mg/L and h is 1.00 m, the maximum breakthrough times achieved for Study A, B and C, are 7.70 hours, 9.27 hours and 6.2 hours respectively. Study B has the longest maximum breakthrough time due to it having operating temperature of 35 °C as well as having the optimum water hyacinth biosorbent particle size which is 0.75×10-3 m.

Predicting the recovery and grade of a rougher flotation circuit from liberation data

A flotation model has been validated against the survey data obtained from a copper rougher flotation circuit with a circulating load. The model was developed using the hydrophobic force as a kinetic parameter, which made it possible to use the contact angles of the free and composite particles as input parameters so that the model can predict both recoveries and grades. The model also recognizes the role of bubble coarsening in determining the froth phase recoveries and grades. The model predictions are in good agreement with the survey data. The size-by-size recovery curve as predicted from the model shows an optimum particle size range that is consistent with most of the operating data reported in the literature. The model suggests that the upper particle size limit may be determined by the instability of the froth phase rather than the turbulence in the pulp phase of a flotation cell.

Topical Application Using Non-ionic Surfactant for Formulation and Evaluation of Flavonoid Proniosomes

It is the goal of this research to examine the topical use of non-ionic surfactant for the Formulation and Evaluation of Flavonoid Proniosomes developed for the transdermal delivery of Rutin. The Proniosomal topical gel was prepared using the slurry technique involved with a non-ionic surfactant, Maltodextrin, Cholestrol and Glycerin. A robust design of experiments was used to optimize the various formulation variables. The optimized PG4 formulation was evaluated for entrapment efficiency, SEM, ATR –FTIR, Viscosity, Spreadability, Drug content, in-vitro diffusion study, and stability studies. PG4 formulation showed the highest entrapment efficiency and the higher percent of drug content. Evaluated for viscosity and spreadability which indicated the ratio of span 80: cholesterol demonstrated presenting some fluctuation. The SEM exhibited spherical vesicles and the optimal particle size for proniosome. In vitro drug release was better drug release throughout the process. After 3 months of storage at refrigerator temperatures, the stability in the presence of the percentage drug content of Rutin proniosomal gel formulation 4. There are several benefits to using Span 80 as the nonionic surfactant in these Proniosomal gel formulations, including increased drug accumulation in the different skin layers and increased carrier potential for the topical administration of rutin for the treatment of rheumatoid arthritis.

Optimization of Parameters of the New Turner-Fairbank Alkali-Silica Reactivity Susceptibility Test (T-Fast)

Abstract Prevention is an effective strategy to avoid damage caused by the alkali-silica reaction (ASR) in concrete structures. The effectiveness of this strategy heavily depends on the use of reliable accelerated tests to determine if an aggregate used in the concrete has the potential to cause ASR. Recently, a new provisional standard test, AASHTO TP 144-21, Determining the Potential Alkali–Silica Reactivity of Coarse Aggregates (TFHRC-TFAST), has been approved by the American Association of State Highway and Transportation Officials. The test accurately predicted the ASR-induced expansion of aggregates used in more than 50 different mortar and concrete samples, including concrete blocks in outdoor testing facilities and concrete in the field. This manuscript presents the results of the collaborative study among three laboratories conducted as part of an overall effort to standardize the new AASHTO TP 144-21. The objectives of the study were to evaluate the suitability of wavelength dispersive x-ray fluorescence (WDXRF) spectroscopy as the main analytical technique, determine the optimal particle size and effect of moisture on calcium oxide (CaO), and evaluate sample preparation on the results. A total of 18 aggregates were evaluated under the TP 144-21 using 4 different CaO samples and 2 sample preparation protocols. The results indicated that the alkali-silica reactivity of the aggregates can be accurately determined by using WDXRF. Upon exposure to the atmosphere, CaO reacts rapidly with moisture to produce calcium hydroxide [Ca(OH)2]. The particle size distribution and amount of Ca(OH)2 in the CaO influenced the ASR classification of marginal (moderately and slow reactive) and nonreactive aggregates. The researchers obtained optimal results using a reagent grade powder CaO with an average particle size of 4.6 μm and less than 5 % of Ca(OH)2. These conclusions were important to validate and optimize the TP 144-21 protocol before launching a wider interlaboratory study.

Passive Filler-Loaded Silicon Oxycarbide Coating on Nickle Alloy with High Thermal Shocking Behavior and Oxidation Resistance.

Polymer-derived ceramic (PDC) coatings of considerable thickness can offer promising protection for metallic and superalloy substrates against oxidation and corrosion, yet the preparation remains challenging. Here, a SiOC/Al2O3/YSZ coating was prepared on a nickel alloy with a spraying method using Al2O3 and yttria-stabilized zirconia (YSZ) as passive fillers. The thickness can reach up to 97 μm with the optimal mass fraction and particle sizes of the passive fillers. A small or isolated SiOC phase is formed in the coating, which can effectively alleviate the shrinkage and cracking during the pyrolysis. The SiOC/Al2O3/YSZ coating exhibits low thermal conductivity and high bonding strength with the substrate. Moreover, the coating shows good thermal shock resistance between 800 °C-room temperature cycles and oxidation resistance at 1000 °C for 36 h. This work provides an effective guide for the design of thick PDC coatings to further promote their application in the thermal protective field.

Application of wood powder for asphalt CO2 emission reduction

In this study, we examined the capacities of three additives, viz. wood powder, Al(OH)3-loaded wood powder, and Mg(OH)2-loaded wood powder, to reduce the emission of CO2 from heated asphalt. We analyzed the effects of particle size and amount of wood powder additive, as well as the loading quantity of Al(OH)3/Mg(OH)2, on the concentration of CO2 emission from heated asphalt. We performed surface morphology and elemental analyses of the modified and unmodified wood powders by scanning electron microscopy in combination with energy-dispersive X-ray spectroscopy. The results indicated that using wood powder additives reduced the emission of CO2 from asphalt at high temperatures. Loading Al(OH)3/Mg(OH)2 was also found to improve the results. The optimal wood powder particle size, amount of wood powder additive, and Mg(OH)2 loading amount were determined to be 80–100 mesh, 2%, and 4%, respectively. Specifically, the rate of reduction of CO2 emission from asphalt reached 92.9–97.9% under these optimal conditions.

Effects of particle size on the separation efficiency in a rotary-drum eddy current separator

Eddy current separation is a technology for recovering non-ferrous metals. The influence of particle size on the separation is of significant importance due to the variety of materials. It was investigated by combining simulations and physical experiments. A strong correlation between the simulation and the experiment was found by Pearson correlation analysis. Then the interaction effects between the particle size and the material type, rotational speed, magnetic pole arrangement were investigated. It shows that an optimal particle size exists for a specific condition, and the separation efficiency of fine particles can be improved by increasing rotational speed, magnetic pole number, and the electrical conductivity/density of material, as well as utilizing torque of Lorentz force. The underlying mechanism of particle size affecting separation was discovered by analyzing eddy current distribution and field gradient. These results provide insight into the design and optimization of eddy current separation for particles of various sizes. • The correlation between simulation and physical experiment was established. • There is an optimal particle size for separation under a specific condition. • The rotation of the particles increases with the decrease of the particle size. • The magnitude and distribution of eddy current is related to the particle size. • Some optimization principles of the eddy current separator were proposed.

Mechanical properties and frost resistance of self-healing concrete based on expended perlite immobilized bacteria

• Self-healing concrete was prepared by pre-wet with SHA. • The compressive strength of self-healing concrete with SHA of 0.6 m 3 was 36.1 MPa. • SHA can improve the frost resistance of concrete. The existing research on self-healing concrete based on Microbial-induced carbonate precipitation (MICP) focuses on the crack-healing effect. However, there are limited studies on the physical and mechanical properties of such concretes. In this paper, the effects of different mixing methods and self-healing agent (SHA) particle size on SHA crushing rate, apparent density, and mixture strength are experimentally investigated. The optimal particle size of the SHA was determined as 1–2.36 mm. Also, it was shown that the SHA should be put in first when mixing. Considering the particle size and mixing method, self-healing concrete specimens with two different sizes and five dosage gradients were prepared. The resulting change in compressive strength and splitting tensile strength of concrete with the SHA amount was determined. Also, the change in frost resistance of specimens after 200 freeze–thaw cycles was evaluated. The results indicate that the compressive strength and splitting tensile strength of concrete gradually decrease with the increasing amount of the SHA. The splitting tensile strength decreases slightly compared with the compressive strength of self-healing concrete. However, the frost resistance of concrete increases firstly and then decreases with the increase of SHA content. Therefore, when the content of the SHA is 0.4 m 3 , the frost resistance of concrete is the best.

Determining concrete properties for different optimized combined concrete mixtures: Novel mathematical approach

Gradation of the granular skeleton significantly influences almost all of the concrete performances. The main purpose of this research work is to develop a mathematical model to characterize the properties of various dry concrete mixtures. The starting point of this work is to propose a single equation to describe continuous aggregate gradations, by combining several ideal grading curves used to design different concrete mixtures, to achieve higher freedom in optimizing the particle-size distribution (PSD) of a concrete mixture. At the design procedure stage, the concrete constituents are selected so that the overall grading of the mix closely follows a given ideal grading curve for specific properties. Using the gradation equation afore-mentioned, a mathematical framework is established to outline several intrinsic factors in the optimized granular skeleton of concrete, characterized by a wide range of particle sizes. The factors developed, directly measured based on the PSD, include the specific surface area and the fineness modulus of the combined grading of the concrete mix particles, as well as the ratio between the granular fractions determined either by area or by weight, and the surface area of the total concrete mixture. The resulting model expressions relate the characteristics of the size distribution of the concrete skeleton, to the parameters in the proposed gradation equation, in particular the distribution exponent. The proposed model could be implemented in the study of the solid phase of concrete, design aggregate gradation to meet certain requirements, or even predict some attributes of the dry concrete mixture. • A unified equation of well-known optimal particle size distributions is developed. • A model is proposed to accurately calculate some properties of the concrete mixes. • The distribution exponent in the proposed equation is the most relevant parameter. • Optimal PSDs are fractal and converge mathematically to the Fung & Dinger model. • The proposed model is suitable for systems with a wide range of particle sizes.

Determination of granulometric composition of technogenic raw materials for producing composite fuel

Purpose. To determine the granulometric composition of technogenic raw materials for agglomeration by the adhesive-chemical method. This approach allows for determining the optimal particle size distribution for obtaining the prepared agglomerated fuel, which has the form of cylindrical rods with a diameter of 30 mm and a length of 50200 mm. Methodology. The granulometric composition of technogenic raw materials was determined using sieve and sedimentation analyses. 38 representative samples of carbon-containing raw materials were subjected to the investigation. Findings. The sieve analysis results of representative samples of coal sludge and culms are presented; their graphical characteristics is given. Sieve analysis of the granulometric composition of samples of carbon-containing raw materials and sedimentation analysis of solid fuel samples with a fraction of fewer than 50 microns is carried out. It has been established that all samples with sizes of more than 56 mm should be subjected to further grinding. Originality. For the first time, studies and comparative analysis of granulometric compositions of technogenic raw materials have been realized, which allows for a reasonable approach to obtaining composite fuel from carbon-containing wastes by the adhesive-chemical method, using various compositions of components. Practical value. The results can process technogenic raw materials to get agglomerated fuel of specified parameters by the adhesive-chemical method and other processing areas, including using carbon-containing waste from various productions.

Meropenem-Loaded Nanostructured Lipid Carriers For Skin and Soft Tissue Infection Caused by Staphylococcus aureus: Formulation, Design, and Evaluation.

Meropenem hydrochloride (MpM)-loaded nanostructured lipid carriers were designed for the effective management of skin infection caused by Staphylococcus aureus via topical route.The solvent evaporation tactic was preferred to develop nanostructured lipid carriers (NLCs). Stearic acid was used as a solid fatty acid; oleic acid was used as liquid fatty acid and Tween 80 as a surfactant. The Staphylococcus aureus burden was analyzed by pharmacodynamic studies. The skin retention was analyzed by fluorescence microscopy.Spherical shape of NLCs was confirmed by TEM. The optimum particle size of the MpM-NLCs was ~ 126.5 ± 0.9 nm with 79.1 ± 2.3% entrapment (EE) and 0.967 mV zeta potential. The in vitro release studies revealed 81.5 ± 3.1% release of drug in 48 h, while the pure drug was almost completely released (98.4 ± 1.4%) within 24 h confirming the potential of NLCs for sustained topical drug delivery. Skin permeation study also revealed better permeation of drug from NLCs than of plain drug. The prepared MpM-NLCs when stored at 4 ± 2°C for 90 days were found to be more stable when the formulation was stored at 28 ± 2°C. The S. aureus burden was analyzed by evaluating the zone of inhibition (ZOI). The ZOI of MpM alone and MpM-NLC gel was measured and compared with that of the control group. The MpM was found significantly effective when its gel was prepared with NLCs because of its enhanced adhesion property occlusion and ability to sustain release.In overall, the study's outcomes validated the relevance of NLC's composition as a vehicle for topical MpM administration in skin diseases caused by Staphylococcus aureus.

Influence of freeze–thaw cycling on properties of cementitious systems doped with fly ash having optimized particle size distribution

Influence of freeze–thaw cycling on properties of cementitious systems doped with fly ash having optimized particle size distribution

In vitro characterization of tofacitinib loaded novel nanoemulgel for topical delivery for the management of rheumatic arthritis

The purpose of the current study is to prepare the tofacitinib (TFB) nanoemulgel (NEG) for topical administration with optimized particle size, high loading efficiency, and better penetration through the skin for the treatment of rheumatic arthritis. The topical delivery of this drug avoids the hazards associated with oral delivery like upper respiratory tract infections and neutropenia. The formulations were prepared using the high-energy ultrasonication method. Oleic acid, tween 80, and propylene glycol were used to prepare TFB nanoemulsion (NE) which is then homogenized with carbopol-934 hydrogel to get the NEG loaded with TFB. The concentration of independent variables such as X 1 (oil phase), X 2 (surfactant), and X 3 (cosurfactant) was optimized using the Box–Behnken design to check its impact on dependent variables such as Y 1 (particle size) and Y 2 (loading efficiency) of the NE. The minimum particle size of 106.3 ± 2.8 nm and maximum loading efficiency of 19.3 ± 1.8% were obtained for NE. The NEGs were evaluated for different organoleptic and physicochemical stability which were found within the normal range. The in vitro release studies showed 89.64 ± 0.97% cumulative release of TFB from NEG over the period of 24 h. The drug release data were fitted in different kinetic models and it followed Higuchi and Korsmeyer-Peppas model clearly showing the non-Fickian drug release from matrix system. As a result, the TFB NEG that have been produced could be a viable delivery mechanism for topical route.

Grinding kinetics of lead–zinc tailing powders and its optimal particle size as a pozzolanic admixture in cement mortar

Recycling lead–zinc tailing powders (LZTPs) as pozzolanic admixtures can effectively solve its stockpiling and hazards problems synchronously, and mechanical grinding can increase the recycling utilization quantity and efficiency of LZTPs. Based on the laser particle size distribution (PSD) and activity index test results, the grinding kinetics, Rosin-Rammler-Bennet (RRB), Swebrec distribution model, and fractal theory of LZTPs have been studied. The results show that the grinding process of LZTPs is described quantitatively in the Divas-Alyaviden grinding kinetics equation, and the grinding efficiency of LZTPs becomes negligible after grinding for 120 min. Moreover, the PSD of LZTPs was remarkably consistent with the RRB, Swebrec distribution model, and fractal theory. The activity index increases with the grinding time. The gray correlational analysis revealed that a particle size range of 3.3 ∼ 6.5 μm presented a maximal positive effect on the activity index. In addition, the leaching toxicity of Pb, Cr, and Cd of LZTPs cement mortar block is below the standard limit of TCLP 1211 and it is safe to use the mortar with the addition of 30% LZTPs. The optimal grinding time for LZTPs was 90 min taking into account the economic and technical benefits.

Experimental Study on the Permeability Damage Mechanism of Gravel Pack Sand Control Medium in Mud Hydrate Reservoirs

Yu, L.; Han, Z.; He, J., and Li, G., 2022. Experimental study on the permeability damage mechanism of gravel pack sand control medium in mud hydrate reservoirs. Journal of Coastal Research, 38(6), 1104–1115. Coconut Creek (Florida), ISSN 0749-0208. The high argillaceous gas hydrate reservoir contains high silt and fine sand content. During the mining process, the fine silt sand will cause blockage of the gravel sand control medium, resulting in reduced medium permeability, that is, penetration damage. Penetration damage will reduce productivity and affect the long-term effectiveness of gravel. For the penetration damage problem of gravel sand control medium, the sand blocking simulation experiment of different reservoir water content, experimental pressure, and gravel specifications were carried out by self-developed sand blocking experiment system. A laser particle size analyzer and electron microscope were used to measure and observe the deposition of sand particles in the upper, middle, and lower layers of gravel layer after the sand retention experiment. The law of permeation damage and the mechanism of media permeation damage were summarized. The research results show that the blockage of sand control media can be divided into four stages: the beginning of blockage, the intensification of blockage, the dredging of blockage, and the balance of blockage. Reservoir water content, experimental pressure, and gravel size all influence permeability damage of gravel. The primary and secondary relationship of the influence of these factors on permeability damage is gravel size, experimental pressure, and reservoir water content. The pressure mainly affects the invasion depth of reservoir sand. The reservoir water content mainly affects the degree of permeability damage. The optimum particle size median ratio D50/d50 is about 25, and the medium has strong antipermeability damage ability and good sand retaining effect.

The Antibacterial Effects of Curcumin-Silver Nanoparticle and Curcumin-Copper Nanoparticle Loaded Niosomes

Background: The threat of antimicrobial resistance is increasing worldwide. Niosomes are a new drug delivery system that increases the antimicrobial potential of antibiotics. Accordingly, this study aimed to evaluate the antibacterial activity of niosomes loaded with curcumin-silver nanoparticles (Cur-AgNPs) and curcumin-copper nanoparticles (Cur-CuNPs). Methods: Initially, a unique combination of metal and curcumin nanoparticles was prepared in free and encapsulated forms to investigate the synergistic effects of the two drugs and to evaluate them through a niosomal carrier. Particle size and polydispersity index were measured using dynamic light scattering (DLS), and entrapment efficiency (EE) was measured through indirect centrifugation. The rate of drug release from the loaded niosomes was assessed through in vitro dialysis. Finally, the antibacterial activity of Cur-AgNPs and Cur-CuNPs loaded niosomes on Staphylococcus aureus and Pseudomonas aeruginosa were measured. Results: The curcumin-loaded niosomal formulations and the simultaneous combination of Cur-AgNPs and Cur-CuNPs had an optimum particle size of less than 200 nm and uniform dispersion. These formulations also showed high entrapment efficiencies and slow release for more than 72 hours. Conclusion: A significant increase in antibacterial activity was observed when using curcumin in combination with metal nanoparticles loaded in niosomes, indicating that the concomitant use of metal nanoparticles and curcumin had a synergistic effect in inhibiting bacterial growth.

Pinocembrin polymeric micellar drug delivery system: preparation, characterisation and anti-hyperuricemic activity evaluation

Aim: Hydrophobic pinocembrin (PCB) was incorporated into a new nano-drug delivery system to enhance solubility, bioavailability and anti-hyperuricemic activity of the drug. Methods: We fabricated PCB loaded polymeric micelles (PCB-FPM) by thin film dispersion method and appropriately determined their physical characteristics. The oral relative bioavailability and anti-hyperuricemic activity of PCB-FPM and free PCB were observed. Results: The optimum particle size of the micelles was 19.90 ± 0.93 nm. PCB-FPM exhibited great stability within 18 days, coupled with lower cytotoxicity and higher biocompatibility. Moreover, the percent cumulative release of PCB-FPM was much higher than free PCB in the dissolution media. The oral bioavailability of PCB-FPM was increased by 2.61 times compared with free PCB. Uric acid (UA) level of rats was reduced in PCB-FPM group (200 mg/kg) by 78.82% comparable to the model control. Conclusion: PCB-FPM may become an ideal strategy to increase oral in-vivo availability and anti-hyperuricemic activity of PCB.

Diagnosing trace metals contamination in ageing stormwater constructed wetlands by portable X-ray Fluorescence Analyzer (pXRF)

In the context of stormwater management in urban areas, more knowledge is needed about sustainable urban drainage systems (SUDS)' long-term performance. This article reports robust calibration of a portable X-ray Fluorescence Analyzer (pXRF) for a purpose of metal accumulation diagnosis in two stormwater constructed wetlands (SCWs). Two 9-year-old SCWs located in Eastern France and composed of a sedimentation pond and a vertical-flow reed-bed filter (RBF#1) respectively a horizontal-flow RBF (RBF#2) are studied. A focus is made on the RBFs where five target metals (Cr, Cu, Ni, Pb, Zn) are monitored to fulfill three objectives: i) develop a robust analyzing method for both field and laboratory scale; ii) compute a distribution mapping of the metals on the substrate; and iii) identify and quantify contamination hotspots. pXRF measurements present an opportunity for a quick field diagnosis of such ageing systems once calibrated. An optimal 63 s beam shooting time was selected for analyses, and optimal particle size distribution was set below 250 μm. As water content is known to be a critical factor influencing measuring quality, correction factors were determined to allow for field campaign up to 30 % of water content. Metals are more accumulated in RBF#1 than in RBF#2 because of the particle size distribution and hydraulic regime of the RBFs. Moreover, RBF#1 displays a higher metal accumulation at the water supply outputs while the distribution pattern in RBF#2 is more diffuse. Only 34 %, resp. 22 % of RBF#1 and RBF#2 surface is contaminated, with corresponding concentrations ranging among the highest 50 % and 25 % concentrations. Eventually, the RBF#1 upper layer (0–5 cm) higher organic matter content generates more metal retention than its deeper layer whereas in RBF#2 metal concentration is homogeneous along depth. These results can be useful to optimize the long-term maintenance and possibly the sizing of such systems.

Preparation of SiCw/Yb2Si2O7 composite powders for environmental barrier coatings

In order to prolong the lifetime of environmental barrier coatings (EBCs) produced by thermal spraying, Yb2Si2O7 powders doped with SiC whisker(SiCw/Yb2Si2O7) as feed stocks was prepared by ball milling, spray drying and vacuum sintering. The morphology, phase composition, particle size, flowability and densification of the powder were analyzed by TG-DSC, XRD, SEM and other methods. The SiC whisker was wrapped into the nanometer agglomerated powder by spray drying. The particle size varied by different spray drying parameters. Powders used for atmospheric plasma spraying were prepared by spray drying, optimal particle size can be obtained under 250 °C inlet temperature, 0.05 MPa atomization pressure, and a peristaltic pump rate of 60 r/min. With the increase of vacuum calcination temperature, the density and flowability of powders are improved, and the composition of the powder changed from Yb2O3 to Yb2SiO5 and finally to Yb2Si2O7. The optimal compactness and flowability of the powders were obtained at the sintering temperature of 1300 °C with minimal surface porosity. SiC whisker was not oxidized during the vacuum sintering and still maintained the original whisker morphology. The densification process of recombinant particles and its mechanism were analyzed in terms of surface morphology and cross section.