Μm Particle Size Research Articles

Can preconcentration of cassiterite from its pegmatite ore reduce processing costs and improve operational sustainability?

Different concentration techniques were evaluated for preconcentration of a mineral ore at a coarser size to avoid energy and resource wastage. Specifically, the aim was to reduce milling costs and energy required in the beneficiation of tin. In this study, cassiterite (0.17% Sn) was the mineral of interest in a pegmatite ore body associated with quartz (SiO2 > 60%) and alumina (Al2O3 > 20%). Three concentration techniques, namely dense media, shaking table, and flotation, coupled with characterization analysis, were used to assess the concentration response. The results confirmed that particle size and mineral liberation impact the separation process. High recovery and grade were obtained with gravity concentration methods (dense media and shaking table) for coarser (+300 to +212 μm) and intermediate (+150 to +53 μm) particle sizes. Lower recovery and grade were identified for much finer sizes (-53 to -38 μm). Flotation produced a high-grade product at a relatively low recovery and appeared to be only applicable to finer grains. Separation efficiency based on Schulz's equation measured a segregation performance of 74.8% for dense medium separation and 60.7% for the shaking table for the coarse and intermediate particle sizes. Flotation only achieved a separation of 30%-40%. The results suggest that use of dense media separation as a rough preconcentration method prior to further grinding, and the utilization of a more advanced concentration technique for mineral recovery and upgrade, constitute a successful approach to improve process economics.

Adsorption efficacy of acetone with zeolitic imidazolate frameworks–8: a mechanistic and kinetic insight

ABSTRACT The zeolitic imidazolate framework-8 (ZIF-8) has been investigated for the dynamic adsorption of acetone from the gas phase. In this study, ZIF-8 was synthesised using a cost-effective and environmentally friendly method and characterised using SEM, XRD, BET, and FTIR. The synthesised ZIF-8 possessed a BET surface area of 1212 m2. g−1 and a 0.64 µm particle size. The dynamic adsorption efficacy of acetone on the thermally pretreated ZIF-8 was investigated in a gas matrix under different operational factors. Increasing the acetone concentration through the adsorbate inlet from 300 to 800 ppm enhanced the adsorption capacity from 114 to 162 mg. g−1, while increasing flow rates from 100 to 200 mL. min−1 diminished the adsorption capacity from 120 to 114 mg. g−1. Additionally, increasing the relative humidity from 30 to 70% diminished the adsorption capacity from 130 to 87 mg. g−1. The acetone adsorption kinetics on ZIF-8 were investigated by the Elovich equation, pseudo-first order (PFO), and pseudo-second order (PSO) models. The statistical parameters indicated that the Elovich equation model is most suitable for representing the kinetic behaviour. In conclusion, ZIF-8 could be introduced as a sorbent with suitable potential for adsorbing acetone from the air in various environmental and occupational settings.

Fine particulate matter as a key factor promoting the spread of antibiotics in river network

The extensive utilization of antibiotics has resulted in their frequent detection, contributing to an increased abundance of antibiotic resistance genes in rivers and posing a significant threat to environmental health. Particulate matter plays a crucial role as the primary carrier of various pollutants in river ecosystem. Its physicochemical properties and processes of sedimentation and re-suspension can influence the migration and transformation of antibiotics, yet the mechanisms of this impact remain unclear. In this study, we investigated the distribution characteristics at the micro-scale of particles in the upstream plain river network of the Taihu basin and the adsorption behaviors of antibiotics in particulate matter. The results revealed that particles were predominantly in the size range of 30 to 150 μm in the river network and highest total antibiotic concentrations in 0 to 10 μm particle size fractions. Adsorption experiments also confirmed that the smaller the suspended particle size, the stronger the adsorption capacity for antibiotics. Spatially, both the average particle size and total antibiotic concentrations were lower downstream than upstream. The distribution mechanism of antibiotic in river network sediments was significantly influenced by frequent resuspension and settling of fine particles with a stronger capacity to adsorb antibiotics under hydrodynamic conditions. This ultimately facilitated the release of antibiotics from sediment into the water, resulting in lower antibiotic concentrations in downstream sediments relative to upstream These findings suggest that fine particles serve as the primary carriers of antibiotics, and their sorting and transport processes can significantly influence the distribution of antibiotics in water-sediment systems. This study enhances our understanding of the migration mechanisms of antibiotics in river networks and will prove beneficial for the development of management strategies aimed at controlling antibiotic dissemination.

New RP-HPLC method for the simultaneous determination of process yield and percentage of encapsulation of Gallein in albumin nanoparticles

A study was performed for the development and validation of a method of High Performance Liquid Chromatography (HPLC) for the identification and simultaneous quantification of Gallein and Human Serum Albumin (HSA). In addition, this work presents the development and physicochemical characterization of this new pharmaceutical formulation of HSA nanoparticles loaded with Gallein for potential use in the treatment of Alzheimer’s disease.The method was developed with the purpose of determining the performance of the synthesis process of nanoparticles and the efficiency of encapsulation of the drug in the nanosystem. The HPLC mobile phase consisted of ACN:H2O:TEA:H3PO4 (50:49.8:0.1:0.1 v/v/v) pumped at a flow rate of 0.8 mL/min, isocratic mode, and the measurement were carried out at 220 nm. Chromatographic runs were performed on a C18 column (150 × 4.60 mm; 5 μm size particles). The HPLC-method was validated following the International Conference on Harmonisation (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines and was used to simultaneously quantify the two components of the nanoformulation. Thus, the values obtained through the validated method were 43 % for drug encapsulation efficiency (% EE) and the synthesis performance (% yield) was 96 %.Moreover, the nanoformulation was characterized by DLS, the results showed that the average particle size was 217 nm, with a PDI of (0.085 ± 0.005) and a potential Z of −29.7 mV.Therefore, the developed method has proven useful in providing accurate simultaneous measurements of HSA and Gallein from albumin nanoparticles. It is advantageous since it is able to reduce the time and facilitate the determination of Gallein encapsulation efficiency and yield of albumin nanoparticles.

Enhanced adsorption of toluene on thermally activated ZIF-67: Characterization, performance, and modeling insights

The zeolitic imidazolate framework-67 (ZIF-67) has been explored for the dynamic adsorption of toluene vapor. We synthesized ZIF-67 through a straightforward room-temperature process and characterized it using XRD, FT-IR, DLS, and SEM techniques. The synthesized ZIF-67 possessed a Brunauer–Emmett–Teller (BET) surface area of 1578.7 m2/g and 0.76 μm particle size. Thermal activation under various conditions revealed that ZIF-67, activated in dry air at 250 °C, demonstrated optimal adsorption efficacy. Its adsorption capacity, time of breakthrough, and time of equilibration were 414.5 mg/g, 420 min, and 795 min, respectively. We investigated the impact of diverse operational parameters on adsorption through breakthrough curve analysis. An increase in the toluene concentration from 100 to 1000 ppm enhanced the adsorption capacity from 171 to 414 mg/g, while breakthrough time decreased from 1260 min to 462 min, respectively.Our findings show that increasing relative humidity from 0 to 70 % reduced 53.7 % in adsorption capacity and 46.3 % in breakthrough time. The competitive adsorption of toluene and ethylbenzene revealed that ZIF-67 had a higher selectivity for toluene adsorption. A 98 % adsorbent's regeneration efficiency at the first cycle reveals its reusability. The experimental data were successfully fitted to the Yan, Thomas, and Yoon-Nelson models to describe the adsorption process. The statistical validation of the model parameters confirms their reliability for estimating adsorption parameters, thus facilitating the design of fixed-bed adsorption columns for practical applications.

Effects of refined grains and doped nanoparticles on fabricating Al2O3 ceramics using binder jetting

Adding sintering additives to fabricate alumina ceramics via the binder jetting (BJ) technique effectively enhances material properties. However, it is still limited by the disadvantages of low relative density and poor mechanical properties. This study proposed reducing matrix particle size and adding nanoscale particles using binder jetting to address the poor densification and strength of printed alumina (Al2O3) samples. Additionally, their effects on the mechanical properties and manufacturability of the material were explored. Numerical simulations were carried out before the experiments to predict the impact of particle stacking on the powder bed using the discrete element method (DEM). Then, filler particles with an average 40 μm size replaced the original 106 μm-sized Al2O3 particles. Subsequently, Al2O3 nanoparticle content in the samples was gradually increased, and the relevant properties of the sintered samples with different compositions were tested. Consequently, the size of the Al2O3 particles and the addition of Al2O3 nanoparticles significantly affects the physical and mechanical properties of the samples. The sample with 106 μm-sized particles has a compressive strength of 58 MPa, while reducing the particle size to 40 μm increases its compressive strength by 26 %. Moreover, the sample's compressive strength could reach up to 330 MPa, an increase of 513 %, and the hardness reaches 1215 HV (11.91 GPa) by expanding the Al2O3 nanoparticles content to 30 %. Additionally, using Al2O3 nanoparticles further reduces the sintering temperature, significantly improving the practicality of Al2O3 printing using binder jetting.

Rp-HPLC method development and validation of finerenone in bulk drug and its formulations

I have done research and achieved the method development & validation of highly accurate, sensitive, precise, rapid gradient system RP-HPLC method of finerenone in both bulk drug & pharmaceutical fixed dosage forms. The separation was achieved on (Agilent) C18 column (4.6 mm*250 mm, 5µm) having this configuration with particle size 5µm & using mobile Methanol: 10 Mm Citric Acid with ratio (38:62) having flow rate 1.0 ml/min. Detection of finerenone was carried out at 258nm. The total chromatographic analysis time per sample was about 15min and retention time of overall analysis is 6.9 min. The response exhibited a linear relationship with concentration in range 98-102 mcg/ml for finerenone correlation coefficient is 0.999 and %RSD is 0.126. The method was validated for accuracy, precision, specificity, linearity & sensitivity. Validation studies demonstrated that the method is simple, specific, rapid, reliable & reproducible.

Experimental Study on Effects of Different Factors on Continuous Detonation of Superfine Lignite: Particle Size and Fuel Equivalent Ratio

ABSTRACT The Rotating Detonation Engine (RDE) is garnering attention for its high thermal cycle efficiency. In order to explore the detonation evolution of lignite/gas/oxygen gas-solid two-phase fuel in RDE, self-developed RDE(L:1000 mm) was used to study the detonation characteristics of lignite dust with ultra-fine particle size in methane/oxygen atmosphere, and the effects of ultra-fine particle size and equivalent ratio on detonation characteristics were explored, achieving stable propagation of rodtating detonation waves (RDW) with durations between 0.611 and 0.684s. The results indicate that the introduction of lignite dust significantly enhances the detonation effects compared to pure methane fuel. An increase in the overall equivalence ratio boosts the propagation velocity of RDW in methane-solid fuels, while a larger lignite dust particle size slows it down. Among ultrafine lignite powder sizes, a 1 μm particle size achieved the highest detonation wave speed. In terms of RDW propulsion, the impact of particle size and methane-solid fuel equivalence ratio on thrust mirrors their effect on detonation wave velocity. At a global equivalence ratio (GER) of 1.8, the specific impulse under different particle sizes was about 0.6 times that at a GER of 1.0, suggesting that an excess of fuel can reduce detonation effectiveness. The optimal specific impulse results were obtained with a lignite powder addition rate of 6 g/s, particle size of 1 μm, and GER of 1.0, reaching 4.6 kN·s·kg−1. The research results reveal the detonation process and detonation propagation law of lignite in methane/oxygen, especially for the future application of lignite in detonation energy release engineering.

Suitability and characterization of pumice, bauxite, and ferrochrome slag as alternative raw materials in vitrified ceramic industry

Since the natural raw materials used in the manufacture of clay-based ceramic products vary greatly in the sintering stage, the resulting products are quite heterogeneous. In addition, different types of waste could be used to make ceramic tiles and bricks. Therefore, this study aimed to investigate the effects of pumice, bauxite, and ferrochrome slag on the vitrified ceramic body. In this context, firstly, binary slip mixtures were prepared by composing 40% clay with 60% pumice, bauxite, and ferrochrome slag one by one, which was reduced to 150 µm in particle size. Then, the mixtures were shaped by slip casting method and sintered at 1000°C, 1100°C, 1200°C, and 1250°C. The qualitative XRD analysis was performed in order to see the phase variation, and physical properties were determined with shrinkage and water adsorption measurements. Since pumice transformed into a glassy phase after sintering at 1100°C, an amorphous phase was observed in all samples produced with pumice. In addition, the mullite development occurred in clay-pumice body composition with the temperature increment. However, tridymite and cristobalite phases were analysed in clay bauxite and ferrochrome body compositions. The shrinkage and water adsorption values, which were high in the samples sintered at 1000°C, began to reduce from 1100°C to 1250°C significantly. In particular, water adsorption reached 0% in the clay-pumice system which was suitable for a fully vitrified-high density standard (ISO13006-10545/98). Besides, the brighter colour was reached in the clay-pumice system while brown and black colour was seen in clay-bauxite and clay-ferrochrome bodies, respectively.

Influencing factors of microplastic generation and microplastic contamination in urban freshwater

This research analyzes data on the microplastic (MP) contamination in the environmental systems (atmosphere, lithosphere, hydrosphere) and the levels of MPs in freshwater of cities with different levels of national income. This study investigates the influencing factors of MP generation, i.e., mismanaged plastic waste, untreated wastewater, number of registered motor vehicles, and stormwater runoff. The statistical correlations between the MP contamination in urban freshwater and the four influencing factors of MP generation are determined by linear regression. The results indicate that MPs are most abundant in aquatic systems (i.e., hydrosphere) and pose a serious threat to the human food chain. The regression analysis shows a strong correlation between mismanaged plastic waste and microfragment smaller than 300 μm in particle size in urban freshwater with high goodness-of-fit (R2 = 0.8091). A strong relationship with high goodness-of-fit also exists between untreated wastewater and microfragment of 1000–5000 μm in particle size (R2 = 0.9522). The key to mitigate the MP contamination in urban freshwater is to replace improper plastic waste management and wastewater treatment with proper management practices.

Simultaneous Determination of Fipronil, Permethrin, and Their Key Related Substances in a Topical Drug Product by a Single Stability-Indicating High-Performance Liquid Chromatography Method.

The topical veterinary drug product containing fipronil and permethrin provides an effective repellent protection and high insecticidal efficacy for dogs. The objective of this study was to develop a stability-indicating high-performance liquid chromatography (HPLC) method for simultaneous detection and quantification of fipronil, permethrin, their key degradation products, and butylated hydroxytoluene (BHT) in a topical drug product. The two active ingredients, their degradation products, and the antioxidant (BHT) were separated by a gradient elution on a Phenomenex Kinetex C18 column (150 × 3 mm, 2.6 µm particle size) maintained at 37°C with H2O acetonitrile isopropyl alcohol 85% H3PO4 (65.5 + 32.5 + 4/0.0053, v/v/v/v) as mobile phase A and acetonitrile (100%) as mobile phase B. The flow rate was 0.9 mL/min, and analytes were detected and quantified at 235 nm. The specificity of the method was demonstrated by adequate separation of fipronil, permethrin, their degradation products, and BHT in the forced degraded finished product. The linearity of the method was demonstrated in the range of 0.2% to 150% of target analytical concentration of both active ingredients and 50% to 150% for BHT. Excellent recoveries of fipronil, permethrin, and BHT in placebo spiked active ingredient solutions in the linearity range showed sufficient accuracy of the method. The LOQ and LOD of the method were determined to be 0.2% and 0.07% of the analytical concentration. A robustness study did not identify any critical parameter that adversely affected the separation and quantification. Here, we report the development and validation of a robust, stability-indicating HPLC method for identification and assay of fipronil, permethrin, and BHT, including estimation of fipronil's and permethrin's degradation products in a topical drug product for dogs. The new HPLC method permits the acquisition of data for all analytes of interest for a topical finished drug product containing fipronil, permethrin, and BHT.

Atmospheric deposition studies of microplastics in Central Germany

AbstractEmission of microplastics (MP) to the atmosphere, airborne transport, and subsequent deposition are now recognized. However, the temporal and spatial resolution of data on MP pollution and knowledge of their atmospheric behaviour and fate is still very limited. Hence, we investigated MP wet and dry deposition in Central Germany and examined the role of weather conditions on MP contamination levels. Monthly samples of dry and wet deposition were taken over an eight-month period (05/2019-12/2019) and analysed by micro-Fourier-Transform Infrared spectroscopy (µFTIR) down to 11 μm particle size and one dry deposition sample was subjected to Raman analysis to determine plastic particles down to a size of 0.5 μm. MP in a size range from 11 μm to 130 μm were detected in all wet deposition samples and in 4 out of 8 dry deposition samples by µFTIR. Polypropylene particles were found most frequently and accounted for 62% and 54% of all particles in wet and dry deposition samples, respectively. Over the eight-month period, wet deposition of MP slightly dominated at the study site and comprised 59% of the total MP deposition. The MP mean total (wet + dry) deposition flux (DF) was 17 ± 14 MP m− 2 day− 1. Extensive Raman analyses of an exemplary dry deposition sample revealed additional plastic particles in the extended size range from 1 to 10 μm resulting in a deposition flux of 207 MP m− 2 day− 1. Our results suggest that MP analysis by µFTIR down to 11 μm may underestimate DF at least by an order of magnitude. More comprehensive studies on submicron plastics and nanoplastics are needed to fully assess air pollution by plastic particles.

Comparison of Three Air Sampling Methods for the Quantification of Salmonella, Shiga-toxigenic Escherichia coli (STEC), Coliforms, and Generic E. coli from Bioaerosols of Cattle and Poultry Farms

Recent fresh produce outbreaks potentially associated with bioaerosol contamination from animal operations in adjacent land highlighted the need for further study to better understand the associated risk. The purpose of this research was to evaluate three sampling methods for quantifying target bacterial bioaerosols from animal operations. A dairy cattle and poultry farm located in Georgia, U.S. were visited six times each. Air was collected for 10 min using: 2-stage Andersen impactor with and without mineral oil overlay and impingement samplers. Sampling devices were run concurrently at 0.1, 1, and 2 m heights (n = 36). Andersen samplers were loaded with CHROMagar™ Salmonella, CHROMagar™ STEC, or Brilliance™ coliforms/E. coli. The impingement sampler contained buffered peptone water (20 mL) which was vacuum filtered through a 0.45 µm filter and placed onto the respective media. Plates were incubated at 37 ℃ for 48 h. PCR confirmation followed targeting ttr for Salmonella and stx1, stx2, and eae genes for STEC. No significant differences were found among methods to quantify coliforms and E. coli. Salmonella and STEC bioaerosols were not detected by any of the methods (Limit of detection: 0.55 log CFU/m3). E. coli bioaerosols were significantly greater in the poultry (2.76–5.00 log CFU/m3) than in the cattle farm (0.55–2.82 log CFU/m3) (p < 0.05), and similarly distributed at both stages in the Andersen sampler (stage 1:>7 μm; stage 2: 0.65–7 μm particle size). Sampling day did not have a significant effect on the recovery of coliforms/E. coli bioaerosols in the poultry farm when samples were taken at the broiler house exhaust fan (p > 0.05). A greater and constant emission of coliforms and E. coli bioaerosols from the poultry farm warrants further investigation. These data will help inform bioaerosol sampling techniques which can be used for the quantification of bacterial foodborne pathogens and indicator organisms for future research.

Integrated Multiplatform Analysis and Separation of Thirteen Flavonoids and Anthraquinones in Seven Medicinal Cassia Species.

Cassia (Family: Fabaceae) species are a large group of flowering plants rich in bioactive anthraquinone and flavonoids used in botanical supplements and nutraceuticals. A simple and reliable high-performance liquid chromatography-photodiode array (HPLC-PDA) method was developed and validated for separating and quantifying 13 anthraquinone and flavonoids. These compounds were further confirmed using an LC-based electrospray ionization mass spectrometry (ESI-MS/MS) method in the leaves and flowers of selected Cassia species. A simple and rapid HPTLC method was developed for chemical fingerprint analysis of all Cassia species. All 13 compounds were chromatographically separated on a Zorbax TC18 (4.6 × 250, 5 μm particle size) analytical column, and 0.1% formic acid and acetonitrile as elution solvents at a flow rate of 0.8 mL/min with detection at 259 nm. For HPTLC fingerprinting, the mobile phase compositions of toluene, ethyl acetate, and formic acid (5.5:4.2:0.6, v/v/v) were optimized to separate and identify all compounds using silica gel 60F254 aluminum plates. The validation data for the developed HPLC-PDA method for 13 compounds showed good linearity (r2 >0.99) with a sensitive LOD (0.082-1.969 μg/mL), LOQ (0.250-5.967 μg/mL), and excellent recoveries (85.22-100.32%). The quantification results were found to be precise and accurate (<5.0% and relative error), -0.77-0.44 with ESI-MS/MS confirmation in the Cassia samples. The novel HPTLC method was excellent separation for 13 compounds, with Rf values ranging between 0.12 and 0.61. The developed HPLC-PDA method was simple and precise and could separate and quantify anthraquinones and flavonoids along with confirmation, using a novel LC-based ESI-MS/MS. The HPTLC method was found to be simple and precise, with excellent separation capabilities for these compounds. This novel multiplatform approach successfully identified and quantified 13 compounds simultaneously using an integration of data strategy in seven medicinally important Cassia species' leaves and flowers.

Green solvent-based lipid extraction from guava seeds and spent coffee grounds to produce biodiesel: Biomass valorization and esterification/transesterification route

Spent coffee grounds and guava seeds were used as representative biomass residues to analyze the replacement of hexane with alternative green solvents for the extraction of lipids and their application to obtain biodiesel with the aim of contributing to the global zero-waste strategy. Lipid extraction studies were performed with these biomass wastes under different operating conditions. The results showed that the green solvents (i.e., ethyl acetate, ethyl butyrate, and ethyl propionate) outperformed the lipid extraction using hexane, achieving a maximum oil recovery of 24% for guava seed and 16.4% for spent coffee grounds, with ethyl propionate. The impact of solvent-to-biomass ratio, extraction temperature, and biomass particle size on lipid recovery from tested biomass residues was analyzed and discussed. The optimal extraction conditions for both biomasses were ethyl propionate, 0.3 mm of particle size and 40 °C; while the best solvent to biomass ratio were 10 and 8 mL/g for guava seeds and spent coffee grounds, respectively. The lipids extracted with green solvents showed similar physicochemical properties and compositions to those lipids extracted with hexane. Lipid extraction kinetics exhibited an endothermic performance. The kinetic data were suitably described with the first-order model (R2 = 0.92 – 1) with kinetic rate parameters in the range of 0.38–0.59 and 0.28–0.72 min−1, for guava seeds and spent coffee grounds, respectively. The lipids extracted from tested biomass were analyzed as raw source for biodiesel production via transesterification. The best reaction conditions to produce biodiesel (90%) were found at 60 °C, 6 h, 15% of catalyst-to-oil, and molar methanol-to-oil ratio of 26:1 using a one-step process. FAME formation up to 96% was obtained using a two-step esterification/transesterification methodology. A detailed characterization of the biodiesel obtained from the lipid fraction from these biomass wastes was also performed, indicating that transesterification reduced the acid value and viscosity to meet the ASTM standard criteria for biodiesel. The study contributes to the valorization of biomass wastes to produce renewable energy and to minimize the waste management problem.

Development and Validation of Novel HPLC Methods for Quantitative Determination of Vitamin D3 in Tablet Dosage Form.

In the present work, an efficient isocratic HPLC method was developed for the precise and accurate estimation of vitamin D3 in tablet form. The chromatographic conditions comprised an L3 silica column (5 µm in particle size, 4.6 mm × 250 mm) with a mobile phase n-hexane/ethyl acetate (85:15 v/v) with a flow rate of 2.0 mL/min and a detection wavelength of 292 nm. The new methodology was validated for accuracy, precision, specificity, robustness, and quantification limits according to an official monograph of USP/BP and ICH guidelines. The peak areas of the six replicates of the homogeneous sample were recorded. The mean value obtained was 67,301, and the relative standard deviation (RSD) was 0.1741. The linearity and range were in the acceptable bounds, i.e., 0.999, which was calculated using regression line analysis. The results show that the method is truly acceptable as the RSD, as the flow rate was 0.81%, while for the mobile phase composition, it was 0.72%, which lies in the acceptable range. The limit of detection (LOD) and the limit of quantification (LOQ) values were 0.0539 µg/mL and 0.1633 µg/mL, respectively. The % RSD of the intra and inter-day precision of the method was deemed acceptable according to the international commission for harmonization guidelines. The developed method has potential to be used for the detection and quantification of vitamin D3 during routine analysis for tablets in dosage form.

Analysis of gas flow and PM movement characteristics inside diesel particulate filter channel

Based on experimental data from engine after-treatment tests, the diesel particulate filter (DPF) microscopic channel model was constructed using UG, and the accumulation of particulate matter (PM) in the deep bed filter layer and carbon deposit layer was analyzed through computational fluid dynamics (CFD). A comprehensive study was conducted on the exhaust gas flow characteristics and PM movement within the DPF channel, and focus on the effects of PM distribution type on capture and regeneration characteristics. The results show that with the increase in particle size in the exhaust, the distribution of PM concentration along the axial position of the channel shows a trend of gradually shifting from 0.2 to 0.25 m (rear section) to 0.125–0.2 m (front section). In particular, PM with 1 μm particle size has a large motion inertia, which is easy to move out of the airflow and deposit in the middle part of the channel. For PM in the front and middle sections of the channel, the airflow obstruction is relatively small, but the heat transfer loss is large, which is not beneficial for PM regeneration in the rear section. Therefore, with the distribution of LID, PD-1, and PD-2, the regeneration efficiency is relatively low, at 50.84%, 55.01%, and 54.59%, respectively.

Microstructure and wear behaviour of AlCoCrFeNi-coated SS316L by atmospheric plasma spray process

ABSTRACT The capacity to endure harsh wear in demanding conditions in stainless steel drops under extreme nature and applications. Protecting the surface by providing a coating layer supports the usage in harsh conditions. In this work, SS316L is coated with AlCoCrFeNi high-entropy alloy (HEA) by atmospheric plasma spray process and annealed at 600°C for 2 hours. The AlCoCrFeNi HEA exhibited spherical particles with bcc phase and 20 µm particle size. The coating morphology revealed a uniform coating with a homogeneous distribution of HEA particles over a thickness of 150 µm. The coating post-annealing offered improved microhardness by 12% than the coated sample before annealing. The wear test was executed by varying load, sliding distance, and sliding velocity at normal temperature, 400°C and 600°C and the corresponding worn surface was analysed. The coated samples after annealing showed 57.6%, 87.5%, and 65.4% improved wear resistance at normal temperature than the coated sample before annealing at minimum levels of load, sliding velocity and distance. The wear rate of coated and annealed samples revealed 5.2%, 4.5%, and 4.4% better wear resistance at 400°C than the coated samples before annealing. The worn surface morphology showcased wear mechanisms to be delamination, abrasive wear, and oxide layer formation under all conditions.

Reinforcement of cement tiles with palm kernel shell particles as natural fibre

This study focused on the experimental investigation of the effect of palm kernel shell particulate reinforcement on the mechanical properties of cement-based tiles. Five samples of cement tiles reinforced with different compositions of kernel shell of 1440 µm particle size at predetermined moisture content were produced against a control sample to ascertain the composition that offered the best suitable properties for the functional requirements of cement tiles at reduced cost. For all the samples produced, evaluations for bulk density, apparent porosity, water absorption capacity, and flexural strength were investigated. The results showed that porosity, water absorption capacity, and apparent density decreased with an increase in the palm kernel shell compositions while bulked density increased. The variation with 80 % cement and 20 % palm kernel shell fibre reinforcement (Sample B) demonstrated optimal tile quality with apparent porosity of 10.35 %, a water absorption capacity of 5.47 %, bulk density of 1.89 g/cm3, and flexural strength of 37.21 kgF/ cm2 . It was evident that the flexural strength of sample B met the ASTMC293 standard cement tiles requirement of 35 kgF/cm2 to 40 kgF/ cm2 thus the optimal volume fraction with improved surface characteristics and recommended for applications where hard and heavy materials are used on tiles.

Simultaneous Estimation and Stability Indicating Method of Vildagliptin And Dapagliflozin by RP-HPLC in Pharmaceutical Dosage Form

Vildagliptin and Dapagliflozin drugs are used for the management of diabetes.The primary objective of the proposed research was to develop and validate analytical methods for simultaneous quantification of vildagliptin and dapagliflozin in pharmaceutical dosage form. Both the drugs were subjected to force degradation to ensure stability of pharmaceutical products. The HPLC method development was carried out on C18 column (250mm*4.6mm,5µm particle size). The chromatographic separation was achieved by isocratic mode with a mixture of Methanol: 0.01% Trifluoro acetic acid (pH-2.78) in the ratio of 95:05 % v/v as mobile phase. Flow rate was kept at 0.8 ml/min and selected wavelength for estimation was 210 nm. Stress testing with acid, alkaline, oxidative and thermal degradation was performed. The retention time was found to be 2.282 min and 4.070 min for vildagliptin and dapagliflozin, respectively. The drugs response found to be linear with correlation coefficient value was nearly 0.999 for vildagliptin and dapagliflozin with linearity range of 10 – 60 µg/ml. The recoveries from studies were found to be 99.78% and 100.17% for vildagliptin and dapagliflozin respectively. LOD and LOQ were found to be lower, hence the method proved sensitivity. Method was validated as per ICH guideline Q2(R1). Drugs had shown more degradation in oxidative condition, 10.62% and 13.52% for vildagliptin and dapagliflozin, respectively. The proposed method would be successfully applied for the stability indicating, impurity separation, qualitative and quantitative estimation of vildagliptin and dapagliflozin in pharmaceutical dosage form and in process quality control analysis.