Sand screens that are widely used in petroleum industry, can fail due to erosion. Since carrying fluid type can have a considerable effect on erosion, in this study, dense discrete phase model (DDPM) was utilized to model sand screen erosion using a CFD-based technique under air, water, and oil flows with four different sand types. The results showed that, erosion was much greater in liquid flows than in air flows. For liquids flows, erosion increases as the uniformity and the sorting coefficients of sand decrease. It has been concluded that, when sand contains various sizes under a certain fluid type, the significance and contribution of particles related parameters on erosion depend on sorting and uniformity of the produced sand.

This study presented a controlled oxygen vacancy formation on stabilization of tetragonal zirconia particles via a nonthermal atmospheric pressure plasma jet (APPJ) with varying the supplied power. The characteristic analyses based on X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy (HR-TEM), Raman, ultraviolet–visible spectroscopy, and ultraviolet photoemission spectroscopy confirm the existence of oxygen vacancies in tetragonal zirconia particles. Production of oxygen vacancies in the prepared zirconia powder is related to the presence of surface defects by observing HR-TEM and further decreases the bandgap as indicated by optical characterization. Thus, it can be anticipated that the research of defect engineering is a promising way to improve the optoelectronic and photocatalytic performance of oxide material via the APPJ method.

In the present work, solid residues and gaseous products after the initial explosion of coal dust were collected by self-made devices, respectively, and their explosiveness was further studied to assess the re-explosion hazard. The results show that the solid residue can explode again, and its explosion pressure (Pex) and pressure rise rate ((dP/dt)ex) both increase gradually as dust concentration and ignition energy increase, but decrease with the larger particle size. Solid residue is characterized by a lower deflagration index (Kst) than raw lignite dust, but it can produce greater severity than some raw high-rank coal dust in some cases. The gaseous products of coal dust explosion are mainly composed of CO, H2 and CH4, and some trace gases. The volume fraction of CO and H2 in the gaseous products rises in proportion to the concentration of coal dust. For coal dust explosion with a concentration >200 g/m3, the gaseous products collected are flammable and have a wider explosion limit and a lower limited oxygen content. This research provides valuable information and reference for future prevention and control of secondary explosion disasters in coal mines.

Supercritical CO2 (S-CO2) power cycle has become one of the most efficient and low-pollution cycle schemes to improve thermal power generation efficiency and reduce energy consumption around the world. In this study, the 3D physical model of a 1000 MW S-CO2 circulating fluidized bed (CFB) boiler with annular furnace is established to simulate the gas-solid combustion process based on the MP-PIC method under the Eulerian-Lagrangian framework. By comparing with the conventional water steam CFB boiler, the S-CO2 CFB boiler has a smooth and stable gas-solid flow pattern with good uniformity of the particle concentration and velocity distribution, indicating that the annular structure and the layout of the heating surfaces is conducive to the gas-solid flow uniformity. The gas-solid phase temperature distributes uniformly basically without sudden rise or sudden drop, and the temperature difference between the solid phase and the gas phase is not large, which reflects the good combustion uniformity of the S-CO2 CFB boiler. Compared with 300 MW and 600 MW S-CO2 CFB boilers, the 1000 MW one shows a higher carbon conversion rate, lower desulphurization effect, and lower nitrogen removal performance with the CO, NO, and SO2 outlet concentration of 0.002%, 5.8 mg/m3, and 125 mg/m3, respectively.

Particle suspension in a turbulent flow can seriously affect the performance of manufactured products in many industrial processes in which the motion of particles cannot be modeled using the numerical method because of the enormous number of particles. Therefore, in this study, a full-scale computational fluid dynamics (CFD) simulation and a 1/5 scaled-down water model experiment were employed to investigate the flow pattern and dynamic behavior of particles in a continuously stirred vessel system. Based on the understanding of the suspension mechanism of settling particles, a particle-suppression device was designed to realize the harmless movement and deposition of particles. The results showed that the flow guidance and division mechanisms of the particle-suppression device led to the inhibition of particle suspensions. In addition, the optimal parameter combination for the device from the water model experiment combined with the orthogonal experimental design, resulted in a 98.3% reduction in the concentration of suspended particles. The suspension of particles was effectively suppressed, which improves product quality and production efficiency. Reliable results can be achieved by combining CFD simulations and water model experiments.

Urea and nitrate-based fuel cells have emerged as promising electricity generation devices. However, most of these catalysts are expensive and limited in supply, which limits their practical applications. Hence, metal-organic frameworks (MOF) have been explored as catalysts due to their low cost, easy preparation, and high redox activity. Here, we synthesize nickel-based MOF (Ni-MOF) via one-pot solvothermal technique as bifunctional electrocatalyst for the direct urea and nitrate fuel cell. The as-synthesized Ni-MOF is deposited on nickel foam (NF) and used as working electrode (Ni-MOF/NF) which demonstrates a peak current density of 188 mA/cm2 for urea oxidation reaction (UOR) and −14 mA/cm2 for nitrate reduction reaction (NRR) at an onset potential of ∼ 1.58 V (vs RHE), and ∼ 1.12 V (vs RHE), respectively The enhanced functionality of the Ni-MOF/NF electrode can be attributed to the high catalytic efficacy of the Ni-MOF. This is mainly due to the presence of multiple oxidation states of N (i.e., Ni2+/3+) and excellent electronic conductivity of the organic ligands in MOF structure. Moreover, Ni-MOF/NF electrodes retain ∼ 71.2% and ∼ 83.9% capacity after 20000 s of UOR and NRR, respectively. This efficacy of the as-fabricated electrocatalyst proves MOF as a promising platform for direct fuel cell applications.

Titanium powder is easily oxidized in the forming and sintering process due to its active chemistry. In this study, a passivation coating is formed on Ti powder surface via SnCl4-Ti gas–solid fluidization reaction using fluidized bed. It is found that at 200–350 ℃, Ti-Sn-Cl-O passivation layer is formed on Ti powder surface on account of the reaction among SnCl4, oxide film on powder surface, and Ti matrix. Upon further increasing the temperature to above 500℃, deoxygenation reaction occurs accompanied by the formation of gaseous TiClm and TiOxCly escaping from Ti powder matrix, resulting in the decreasing of surface oxygen content. Besides, elemental Sn and Ti-Sn compounds are formed on Ti powder surface, and part of Sn is diffused into titanium matrix. The passivation behavior is mainly consisted of oxygen film destruction and oxygen removal with the fluidization temperature increasing. Overall, the suitable temperature is about 350℃ to form a passivation coating on Ti powder surface, which can achieve oxidation isolation and deoxygenation in subsequent forming and sintering process.

Oxygen reduction reaction (ORR) is an important reaction which is widely applied in advanced oxidative processes (AOP) through the in-situ electrogeneration of hydrogen peroxide. Oxygen gas can either be reduced to hydrogen peroxide via two-electron pathway or be converted to water in a competitive way via four-electron pathway. In this study, we report the effective enhancement of H2O2 generation in K2SO4 0.1 mol/L (pH 2) through the application of Printex L6 carbon (PL6C) modified with zirconium/niobium (ZrNb) and zirconium/molybdenum (ZrMo) oxides compared to unmodified PL6C. The proposed catalysts were prepared by the polymeric precursors synthesis method (on carbon). The catalysts were analyzed by X-ray fluorescence (FRX), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), and were electrochemically characterised by cyclic voltammetry (CV) and hydrodynamic linear sweep voltammetry (LSV). The electroactivity of ZrNb/PL6C and ZrMo/PL6C oxides was analyzed in the ratio of 50/50 w/w. The results obtained from the electrochemical characterisations of the electrodes showed that the application of 5% ZrNb/PL6C and 1% ZrMo/PL6C yielded H2O2 selectivity of 84.3 and 77%, respectively, compared to 84.3% recorded for the unmodified PL6C. Also, based on the application of a determined current density, 5% ZrNb/PL6C and 1% ZrMo/PL6C recorded a potential shift of 200 and 400 mV to less negative potentials, respectively, compared to the unmodified PL6C, which implies in less energy consumption. The results obtained from the morphological and surface characterisations of the materials pointed to a practically homogeneous distribution of ZrO2, Nb2O5, and MoO3 with particle size of ca. 5 nm on the PL6C surface compared to the unmodified PL6C which exhibited particle size of ca. 30–50 nm.

p-Toluenesulfonamide (PTS) is a developing small molecular anticancer agent with good lipophilic ability. Microparticle production of PTS is an approach to enhance the dissolution profile and explore the potential for novel drug delivery system design. This study employed the rapid expansion of supercritical solutions (RESS) process to produce microparticles of PTS using supercritical carbon dioxide as the solvent. To meet the concept of quality by design in the pharmaceutical industry, the effects of process parameters in RESS operation were investigated and optimized by a design of experiments approach, the Box-Behnken Design (BBD). The design space for microparticle production of PTS was shown, and the analysis of variance (ANOVA) confirmed the significance of process parameters. According to the BBD study, at the optimal operating condition, PTS microparticles were successfully generated from the unprocessed mean size of 240.3 μm to 1.3 μm. The solid-state property of the unprocessed and micronized PTS powders was compared and confirmed consistent through the PXRD, DSC, and FTIR analysis. Finally, the dissolution profiles of PTS before and after the RESS process were determined, and the dissolution rate of RESS-produced PTS microparticles was enhanced 1500 times compared with the unprocessed PTS.

Industrial powders are prompt to be airborne during processing. High dustiness levels may cause process complications like cross-contamination, product loss and filter clogging while increasing the risk of inhalation, dust explosion and fire. Thus, dustiness is often associated with occupational exposure. Despite this, powder products are usually composed of multiple ingredients with silica nanoparticles (S-NP) systematically added to ease their handling. Surprisingly, the relationship between dustiness and product formulation has not been commonly studied. This work investigates the influence of S-NP, SIPERNAT D10 (SD10), on the dustiness of four industrial powders–Avicel PH102, wheat flour, joint filler, and glass beads–using two standard methods: the rotating drum (EN 15051–2) and the vortex shaker (EN 17199–5). Our results show that the dustiness of mixtures powder + SD10 are statistically higher than those of the powder alone and can reach the levels of SD10. TEM micrographs from airborne particles collected in the vortex shaker showed that SD10 detached from the surface of the powder during aerosolisation, emitting nanometric dust; adding SD10 increases the potential for inhalation exposure during industrial processing and handling. Surface energy analysis by inverse gas chromatography (IGC) leads us to conclude that stronger powder-to-SD10 interactions result in less dust emission.

In this research, porous W matrixes for dispenser Ba-W cathodes were prepared by metal injection molding (MIM) using W powders with different particle shapes as raw materials. Other than investigating the effect of the powder particle shape on the pore characteristics of the porous W matrix, the influence of the powder particle shape on the emission properties of the Ba-W cathode was also investigated. Irregular W powder particles had higher surface roughness and specific surface area than the spherical W particles, resulting in sinuous pore channels and higher pore-specific surface area in the prepared W matrix. The emission current density of the cathode processed from the irregular powder was thus improved as the level of Ba–O dipoles, covered on the emission surface, was increased. This is due to the high pore-specific surface area offering a high contact area between W and impregants in the cathode.

Entropy production theory based on the second law of thermodynamics was introduced for evaluating the flow field inside the turbo air classifier. The three new types of rotor cage with the wedge blades, the inverted wedge blades and the spindle blades were designed, and the flow field and the classification performance of the classifiers were investigated. The results show that, compared to the rectangular blades, the productions of total entropy, turbulent entropy and wall entropy of the wedge blades are reduced by 17.3%, 25.86% and 3.34%, respectively. The corresponding effective airflow area increases by 7.5%, and the residence time of 5 μm particle is shorten by 16%. The classifier with the wedge blades has smaller cut size and higher classifying sharpness. The results validate that the turbulent entropy generation can be an indicator for monitoring the overall flow field and the classifiers’ performance.

Amorphous drug nanoplex represents one of the most promising solubility enhancement strategies of poorly-soluble drugs. Solubility enhancement capability of nanoplex hitherto has been demonstrated for nanoplex suspension and lyophilized/spray-dried nanoplex, but not for its oral tablets. Using ciprofloxacin as the model poorly-soluble drug, we investigated spray gelation (SG) of alginate and spray freeze drying (SFD) with cryoprotective mannitol, as the nanoplex’s granulation methods. Both granules were evaluated in terms of their morphology, physical form, flowability, drug content, preparation yield, dissolution profile, drug solubility enhancement, and storage stability. Subsequently, tablets of the granules were prepared and characterized in terms of their drug content uniformity, weight variation, friability, hardness, dissolution profile, and solubility enhancement. The results showed that nanoplex in SG granules was embedded in dense amorphous alginate matrix, while nanoplex in SFD granules was dispersed in porous crystalline mannitol particles. Despite their distinct morphology, physical form, and dissolution profile, the two granules exhibited similar drug solubility enhancements. Both granules were readily compacted into tablets with minimal changes in their dissolution and solubility enhancement after tableting. The present work demonstrated SG and SFD as viable granulation methods of nanoplex, with SG granules exhibiting superior flowability, stability, but lower yield.

Due to its rich mineralogy, fly ash (FA), an industrial waste, has been used to combat erosive, corrosive environments. Powder flowability dictates coating properties. In this investigation, raw FA powder was obtained from a thermal power plant and sieved in various sizes to assess their flowability. Powder's physical characteristics, such as specific surface area, Blaine's fineness number, and bulk density, were determined, and their influence on powder flowability was analyzed. Of these properties, bulk density affects more. Rietveld refinement was performed on the powder to quantify the phases. The powders had 45.08 ± 11.38 amorphous and 11.00 ± 2.76 % of mullite phases. Later, alumina was added between 10 and 50 wt% to FA, and samples were subjected to high-temperature X-ray diffraction at 1150 °C. A ∼32.27% rise in Mullite content was observed for 50 wt% alumina, with ∼119% decrease in the amorphous phase. Finally, one set of FA without additives coating was plasma sprayed onto a marine-grade steel substrate. The coating showed ∼17.31 ± 0.6% of mullite and ∼69.43 ± 0.6 % of the amorphous phase, with decent Mechanical properties. Therefore, 50 wt% alumina in FA powder has improved the mullite phase, bulk density (43%), and flowability by decreasing the amorphous phase content.

Nanocomposites of iron-doped hydroxyapatite and carbon dots were synthesized through green synthesis processes, using Yerba Mate (Ilex paraguariensis) as a precursor. A thorough characterization of the particles was carried out by HRTEM, XRD, FTIR, DLS, XPD, and static contact angle. The characterization indicated that the crystallinity, surface charge, and wettability depend on the synthesis parameters.Carbon dots-doped materials, YMnAp@CD and YMFenAp@CD, showed amphiphilic properties with the capacity to adsorb Crystal violet (CV) and Oil Blue A (OBA) from aqueous or toluene-based solutions. The mentioned materials showed the highest number of adsorption sites, with values of 2.95 ± 0.05 and 3.18 ± 0.04 mmol CV/gads and 1.65 ± 0.02 0.97 ± 0.06 mmol OBA/gads on monocomponent systems, and through a multi-component analysis, the competition for adsorption sites was elucidated.

Sodium lignosulfonate (SL) is a powder-like by-product of the pulp and paper industry derived from lignocellulosic biomass. SL can potentially be a low-cost and highly efficient binder for the pelletization of iron ore powder in the ironmaking industry because it is a natural polymer compound containing multiple functional groups, such as hydroxyl, carboxyl, and sulfonic acid. In this paper, the strong organic binder, namely SL, was used to enhance the compressive strength of the limonite pellet, which is required to reduce VOC emission during the iron-making process. The limonite pellets' pellet size variation and compressive strength prepared with SL-based binders were studied at a temperature range from 900 °C −1100 °C. Experimental results showed that the compressive strength of the preheated pellets was the highest at a preheating temperature of 1100 °C, reaching 342.55 N/P which is qualified for the subsequent iron-making process. These experimental results provide essential references for optimizing the preparation of limonite pellets with SL-based binders. Furthermore, this study employed artificial neural networks to process experimental data and generate predicted values for corresponding experimental conditions. The predicted results closely matched the observed values, further assisting enterprises in accelerating their digitization and automation processes.

It is of crucial importance to understand the impact of micro/nanoplastics on microorganisms in the environment. In the present paper, we have comprehensively investigated the effect of NaCl salt concentration (CNaCl = 5–600 mM) on the adhesion and toxicity of positively charged polystyrene nanoparticles (pPS-NPs with 115-nm diameter) toward bacterium Escherichia coli K-12 after a short-time exposure (0.5 h) at 25 °C, in comparison with that toward yeast Saccharomyces cerevisiae. Unlike S. cerevisiae, the rod-shaped cells of E. coli exhibited the great surface potential in magnitude and the salt-concentration-dependent size with a minimum at CNaCl = 100 mM. The adhesion and toxicity of pPS-NPs toward E. coli were similar to those toward S. cerevisiae, except for some points. Especially, the number of the NPs adhered to a cell as a function of CNaCl at the higher NP mass doses exhibited an M-shaped profile with a local minimum at CNaCl = 100 mM, which is mainly explained by the aforesaid salt-concentration-dependent cellular size. The E. coli cells significantly covered with pPS-NPs at CNaCl = 100–150 mM remained alive. The tolerance of bacterium E. coli to exposure of NPs could result from its strong environmental adaptability.

In recent years, the issue of global warming caused by CO2 emissions has become a critical problem and poses a worldwide challenge. To address this issue, we have developed a bifunctional catalyst that can convert CO2 to lower olefins in a single stage. Our bifunctional catalysts are a combination of two catalysts, a CO2-to-methanol hydrogenation catalyst (Zn-doped ZrO2, named ZnZrOx) and a methanol-to-olefin catalyst (MOR-type zeolite, named MOR104). In this research, we examined the impact of various mixing modes of the two catalysts on product distribution. We tested four different mixing modes using a down-flow fixed bed reactor: (a) ZnZrOx in the upper layer and MOR104 in the lower layer, (b) catalysts were mixed randomly after being pelletized separately, (c) MOR104 in the upper layer and ZnZrOx in the lower layer, and (d) granulated catalyst produced by physically mixing both catalyst powders. Our findings indicated that the best performance was achieved with catalyst (d), where the two catalysts were mixed in close proximity. This proximity resulted in efficient supply of methanol produced on ZnZrOx to MOR104. In other words, the MTO reaction in MOR104 efficiently consumed methanol molecules produced via equilibrium-limited CO2-to-methanol hydrogenation. When ZnZrOx and MOR104 were thoroughly mixed, the conversion of CO2 to methanol shifted towards the product side, resulting in a greater overall utilization of CO2. Furthermore, the bifunctional catalyst we developed was stable for six hours. Since there have been few studies of bifunctional catalysts containing zeolites other than ZSM-5 and SAPO-34, this study opens up new opportunities for bifunctional catalysts specialized for one-pass hydrocarbon synthesis through CO2 hydrogenation.

Agricultural waste, rice husk (RH) was treated to obtain rice husk ash (RHA) and utilized as silica precursor in hydrothermal synthesis of TS-1 zeolite. Results of characterization analyses, XRD, FTIR, FESEM and N2 adsorption-desorption, confirmed that TS-1 zeolite was properly synthesized from RHA. Synthesis of TS-1 was also carried out with TEOS for comparison of textural properties. Prepared TS-1 zeolite with RHA was used as support for HDS catalyst preparation. Molybdenum active phase and nickel promoter were loaded via three different methods, impregnation, precipitation and solution combustion, to obtain NiMo/TS-1 hydrodesulfurization catalyst. EDX dot-mapping and H2-TPR analyses indicated on better preparation of NiMo/TS-1 catalyst by solution combustion method, in terms of distribution and amount of successfully loaded metal over the support surface. Hydrodesulfurization (HDS) activity of synthesized samples was examined in hydrodesulfurization of heavy oil feed, carried out in a continuous fixed bed reactor apparatus. Performance test revealed that NiMo/TS-1 catalyst synthesized by solution combustion method eliminated 63.5 % of the feed sulfur content (4000 ppm); a superior hydrodesulfurziation activity, compared to the samples prepared via impregnation and precipitation methods with 40.8 % and 50.2 % sulfur removal, respectively. Amount of sulfur present in the feed and treated product was determined with GC-MS analysis.

In the present work, a series of molecular dynamics simulations are conducted to figure out how sintering parameters would influence the atomic structure, sintering mechanisms, and elastoplastic properties of sintered Al-Cu nanoparticulate systems. For this purpose, first, utilizing the atomic potential energy diagrams, the suitable sintering temperatures for the introduced nanoparticles (NPs) have been calculated. NPs are then sintered at the temperatures of 410, 510, 600 and 680 K, and microstructural changes have been probed during the process. Finally, employing a uniaxial tensile test, the sintering temperature and holding time effects on the tensile behavior of the sintered products are studied in detail. Our simulation results indicate a strong correlation between the crystalline structure of the sintered NPs and the process temperature. It is also concluded that the main sintering mechanism at low-temperature conditions is dislocation slip, while at elevated temperatures, the sintering mechanism switches to diffusion-based phenomena. Moreover, it is revealed that increasing the sintering temperature from 410 to 680 K enhances the Young modulus of the samples monotonically, while the greatest yield strength is achieved at 600 K. Similar correlation is also found between the holding time and mechanical properties of the final product.