Mixing Speed Research Articles

A Bearing Fault Diagnosis Model Based on a Simplified Wide Convolutional Neural Network and Random Forrest

Bearings play a crucial role in the complex mechanical systems of ships, and their operational status is closely related to vibration signals. Therefore, analyzing bearing signals plays an important role in the field of fault diagnosis. In order to solve the problems of low accuracy and slow response speed in fault diagnosis through vibration signals at mixed speeds, this paper introduces an improved Simple Window Deep Convolutional Neural Network with Random Forest (SWDCNN-RF) model on traditional Wide Convolutional Neural Network (WDCNN). It was verified through the publicly available dataset of ball bearings from Western Reserve University in the United States. It was found that the improved model increased speed by 38.51% and accuracy from 97.5% to 99.6% at epoch = 50, and also achieved faster convergence and smaller fluctuations during training. This study is of great significance for determining the occurrence time and type of bearing faults, and provides criteria for reliability evaluation and fault diagnosis of equipment using bearings.

Stirring speed effect on processing of modified asphalt with Sebs-G-Ma copolymer and sulfur

Abstract This study focuses on the improvement of the thermo-mechanical properties of AC-20 asphalt A by incorporating Polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene-graft-maleic anhydride (SEBSR) and sulfur (S). The effect of two different mixing speeds, 1000 and 1500 rpm, was investigated to understand how the size of the polymer particles impact the materials functions. The characterization of the samples was carried out by rheometry, specifically studying the G′, G′′, and tan δ. The results showed significant changes in the rheological properties of the modified asphalts at higher stirring speeds and in the presence of sulfur. With this modification in the process, a material can be obtained with the same proportion in the composition but with more convenient thermo-mechanical properties for the application. Graphical abstract

Influence of Selected Conditions on the Efficiency of Carbonate Precipitation of Cu(II), Ni(II), Pb(II) and Zn(II) Ions

Optimal process conditions for carbonate precipitation of selected heavy metal ions were tested in laboratory conditions using Na2CO3. To the prepared synthetic monocomponent and binary multicomponent solutions of heavy metals with initial concentrations of 500 mg/L, Na2CO3 was added in certain doses at selected mixing speeds (0, 100, 300 and 800 rpm) and mixing time (0, 15, and 30 minutes). The results show the removal efficiency at optimal mixing speeds for monocomponent metal solutions were: Cu(II) 96.394% (300 rpm), Ni(II) 94.594% (0 rpm and 800 rpm), Pb(II) 75.968% (0 rpm ), Zn (II) 99.311% (0 rpm). In binary multicomponent mixtures Cu(II)-Ni(II) and Pb(II)-Zn(II) the removal efficiency results at optimal mixing speeds were: Cu(II) 96.394% (100 rpm), Ni(II) 95.528% (800 rpm), Pb(II) 99.536% (300 rpm), Zn(II) 98.945% (100 rpm). Also, the results of the efficiency of heavy metal removal due to the influence of the contact time of the precipitant and heavy metal ions in monocomponent solutions show the following values: Cu(II) 99.940% (0 min), Ni(II) 94.612 % (0 min), Pb(II) 77.925 % (15 min), Zn(II) 99.324% (30 min), while in binary multicomponent mixtures Cu(II)-Ni(II) and Pb(II)-Zn(II) they were for Cu(II) 96.247% (30 min), Ni(II) 95.521% (0 min), Pb(II) 99.350% (30 min) and Zn(II) 98.944% (0 min). Examination of the influence of the mixing speed of monocomponent solutions showed that the efficiency of removing heavy metal ions was in most cases the best without mixing. Effect of metal-precipitant contact time on the efficiency of heavy metal ion removal showed that in half of the examined metals, the optimal values ​​were chosen as the best (0 and 30 min). It can be concluded that this method based on chemical precipitation using Na2CO3 with optimal parameters such as contact time and mixing speed, can be used in the treatment of industrial wastewater.

Dissolution behavior and kinetic investigation of Mg+2 in solution in the reaction of colemanite ore with propionic acid

Colemanite ore, which is one of the most significant commercially substantial boron minerals, is used to produce various boron compounds in the industry with its rich B_2 O_3 content. Calcium propionate, used in the food industry, is formed as a by-product in its production. In the production of boric acid from colemanite, the use of different solvent reagents is at the forefront to prevent the formation of Mg^(2+), Ca^(2+) and SO_4^(2-) impurities and borogypsum by-products. For this reason, in our study, the dissolution kinetics of colemanite ore in propionic acid solution in an aqueous medium were carried out in a batch reactor system. As dissolution parameters; reaction temperature, solid/liquid ratio, propionic acid (CH_3 CH_2 COOH) concentration, stirring speed and particle size were selected as. According to the experimental results, the amount of Mg^(2+) passed to the solution; was observed that the solution increased with the increase in reaction temperature with the decrease in solid-liquid ratio, grain size, and acid concentration. In addition, it was determined that the mixing speed was not effective. Obtained experimental data were analyzed according to homogeneous and heterogeneous reaction models using the Statistica 10.0 package program. It was determined that the dissolution kinetic of Mg^(2+) passing to solution conformed to the "Avrami model" and activation energy (E) was calculated as 8.18 kJ⁄mol.

Investigation of Dyestuff Recycled from Wastewater Containing Indigo/Sulfur Dyes

Turkey is one of the important centers of denim fabric production in the world. Warp yarn is usually dyed using indigo and/or sulfur dyes according to the impregnation method. The common feature of these two dyes is that they are insoluble in water and dye temporarily with a reduction reaction. The recovery of dyes in wastewater is targeted. Wastewater containing indigo and sulfur dyes taken from İskur Denim was sedimented using the chemical flocculation technique and solid material was obtained after drying. The sedimentation process was affected by the pH of the environment, the mixing speed and the concentration of sedimentation chemicals. The best sedimentation was achieved by adding flocculators supplied by AKKİM to the wastewater sample in the pH range of 8-8.5. The obtained sludge was subjected to condensation reaction with the developed binding agent. The energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the dyes obtained from indigo and sulfur wastewater were determined as -4.78 eV and -4.04 eV, respectively, by cyclic voltammetry. These values are very close to the original dyes and give hope for dyeing performance.

Coagulation-Flocculation/Pyrolysis Integrated System for Dye-Laden Wastewater Treatment: A Techno-Economic and Sustainable Approach

While several studies have employed coagulation-flocculation (CF) for textile wastewater (TW) treatment, conventional process optimization techniques cause insufficient pollution reduction and large sludge volume generation that deteriorate the environmental matrix and elevate the system’s operating cost. To avoid these drawbacks, this study focuses on optimizing an integrated CF/pyrolysis process using artificial intelligence technique and response surface methodology (RSM) for the dual benefit of TW treatment and biochar production. In the CF experiment, water hyacinth (WH) was employed as a bio-coagulant material for TW treatment under different pH, coagulant dosage, mixing speed, and settling time levels. Under the optimum CF conditions yielded by RSM and artificial neural network (ANN) models (initial pH: 5.5 vs. 5.7, WH dosage: 3.76 g/L vs. 3.5 g/L, settling time: 116 min vs. 102 min, and slow mixing speed: 25 rpm vs. 23 rpm), incomparable removal efficiencies for dye (87.3% vs. 91.3%) and turbidity (93.4% vs. 98.2%) were obtained. These removal efficiencies dropped to 83.5% and 87.6%, respectively, for operating the CF process using unoptimized operating factors. The pyrolysis of post-coagulation sludge yielded a carbon-rich biochar material characterized by a porous structure and abundant cationic microelements. The integrated performance of the CF/pyrolysis scheme under ANN-based optimal conditions achieved a shorter payback period of 5.2 years compared to RSM (5.7 years) and unoptimized (7.9 years) conditions. Furthermore, the optimized scheme supported several sustainable development goals that complied with clean water, good health, and climate change mitigation.Graphical

Comparative Study on Polyelectrolyte Complex Formation of Chitosan and Pectin or PEMA: Effects of Molecular Weight and Mixing Speed

Polyelectrolyte complexes (PECs) have gained increasing attention in recent decades due to their importance in various applications, such as water treatment and paper processing. These complexes are formed by mixtures of polycations (n+) and polyanions (n−), known as polyelectrolytes (PEs). In this study, a series of PECs were prepared with different molar charge ratios (n−/n+) using biopolymers such as chitosan (lch) and pectin (p) at pH 5, in addition to the synthetic polymer poly(ethylene alt maleic acid) (PEMA) at the same pH. Two types of chitosan—low molecular weight chitosan (lch) and high molecular weight chitosan (hch)—were used as polycations, and these were mixed with two types of pectin with either a high esterification degree (hp) or a low esterification degree (lp), as well as PEMA as polyanions. These components interacted via electrostatic forces to form the following PEC combinations: (lch&lp), (lch&hp), (hch&hp), and (lch&PEMA). The charge density, turbidity, and particle size of the formed PECs were examined to evaluate the influence of molecular weight and mixing speed on the formation process.

EFFECT OF INCORPORATING RAM-FAT AND OIL INTO THE BITUMEN GRADE 60/70

The ability of a pavement to resist fatigue cracking, rutting, and thermal cracking is mostly dependent on bitumen, which assists in minimizing the occurrence of pavement distress. The objective of the study is to determine the optimum ram fat and oil (RFO) content suitable for the application of bituminous mixtures. Saturated fats and oils consumption in excess can boost blood levels and may lead to bad low-density lipoproteins cholesterol, which raises the danger of heart failure and stroke. To minimize this problem, this study encourages the incorporation of RFO into bitumen to reduce the consumption of fats and oils in our society. The characteristics of the standard and RFO-modified binders were evaluated by penetration, softening point, and ductility tests. The RFO content (1.0%, 2.0%, 3.0%, 4.0%, and 5.0% by mass of the bitumen) was blended with the bitumen for 35 minutes with a mixing speed of 1000 rpm. The result of the optimum RFO content was discovered at 3.0% which improved the performance of the mixture. It was found that bitumen grade 60/70 documented a significant improvement with the addition of RFO content. The optimum RFO content can be raised with a smaller bitumen grade.

Determination of Toxicity Using the Activated Sludge Respiration Inhibition Test and Identification of Sensitive Boundary Conditions

Toxic pollutants in wastewater can negatively affect biological processes in WWTPs, leading to operational failures and environmental harm if undetected. This study refines the ISO 8192 method for enhanced toxicity detection in WWTPs, meeting the critical need for rapid and reliable monitoring. The novelty of this study lies in the optimization and identification of sensitive boundary conditions (e.g., temperature stability, consistent mixing speed, and immediate aeration), which are crucial for ensuring the accuracy and reproducibility of the method. The optimization results indicate that sludge prepared via settling yields EC50 values comparable with those achieved with sludge prepared via centrifugation. For total oxygen consumption inhibition, the EC50 values were 9.22 ± 0.21 mg/L (centrifuged) and 9.42 ± 0.16 mg/L (settled), with nitrification inhibition values of 1.92 ± 1.24 mg/L and 2.17 ± 1.5 mg/L, respectively. The verification results obtained using samples from the Graz and Trofaiach WWTPs demonstrate EC50 values of 12.38 ± 2.05 mg/L and 12.25 ± 0.62 mg/L (total oxygen consumption inhibition), 23.31 ± 4.62 mg/L and 19.32 ± 0.29 mg/L (heterotrophic inhibition), and 1.54 ± 0.94 mg/L and 3.48 ± 2.65 mg/L (nitrification inhibition), which are all within the accepted ranges of validity of the method. The optimized ISO 8192 method provides a robust and efficient tool for WWTPs, enabling rapid responses to toxicity events and supporting regulatory compliance. These refinements enhance the practicality and reliability of the method.

STRENGTH STUDY OF MACHINE TOOL BEDS WITH CURVILINEAR STIFFENERS FROM POLYMER CONCRETE

This study addresses enhancing the strength of metal-cutting machine tool beds made from polymer concrete by optimizing the internal cross-section design through spiral stiffeners. Key factors influencing the bed’s strength include the composite preparation technology, the mixing speed (600 - 800 rpm), and duration (3 - 4 minutes). A strong correlation exists between spiral pitch, mixing speed, mixing time, and the bed’s strength.

Powder Structure Control Technology in the Solvent-Free Dry Electrode Forming Process of Lithium-Ion Battery and Its Battery Performance Evaluation

Lithium-ion batteries (LIBs) are widely used as power sources for electrified vehicles because of their high energy density and power density. As demand for LIBs increases rapidly, improving the manufacturing process of making LIBs is a key to further decreasing the cost and expanding the market of LIBs for many applications, especially for electric vehicles. Electrodes for LIBs are generally manufactured by the slurry-based electrode forming process, in which active materials (AMs), conductive and binding additives (CBA) are dispersed in a solvent, and the material prepared as a slurry is coated onto a current collecting foil, followed by drying to remove the solvent. Although this slurry-based electrode forming process is a simple way to form electrodes but requires a large amount of energy for the drying process because the solvent must be evaporated at high temperatures in a drying oven. Furthermore, N-methyl-2-pyrroidone (NMP), which is the most common solvent for cathode slurries, must be recovered and processed due to its high toxicity. To meet these requirements, a solvent-free dry electrode forming process have been proposed to reduce environmental impact and cost in the electrode manufacturing process. Since dry electrode forming processes require no solvent from electrode material mixing steps to an immobilization step on a collector foil, there is no need to either dry or recover solvents. Therefore, the dry electrode forming processes can significantly reduce the material cost and energy consumption in battery manufacturing. From the viewpoint of the battery performance, the electronic and ionic conduction within the electrode is affected by the internal structure of the electrode, the composition and distribution of the CBA within the electrode, as well as the shape, connectivity, and volume fraction of pores within electrodes. In the slurry-based electrode forming process, it is difficult to control the distribution of CBA due to interactions in the slurry, such as the binder migration phenomena during drying. In contrast, the dry electrode forming process directly fabricates electrode films from electrode powder mixture, which consists of the AM and CBA. As a result, the electrode structure can directly reflect the morphology of the electrode powder without being affected by the binder migration phenomenon. Therefore, dry electrode forming processes have big potential for not only reducing the manufacturing cost but also controlling electrode structure and thus designing battery performance. However, there is little discussion regarding the optimal morphology of electrode powder mixture to improving battery performance for dry electrode forming process. Therefore, in this study, we propose a method for designing the optimal morphology of the electrode powder for improving the battery performance. We investigate how the morphology of the electrode powder mixture affects the structure and battery performance of lithium-ion battery electrodes fabricated using the dry electrode forming process. We demonstrate that the distribution of conductive additives and binders (CBA) on the active material (AM) can be controlled by adjusting the rotation speed of the dry mixer. Furthermore, we show that the rate performance of the battery can be improved by controlling the distribution of CBA. We also discuss the internal structure of the electrodes, especially focusing on the electronic and ionic conductive pathways, to elucidate the relationship between the electrode structure and battery performance.

Enhancing accuracy and reproducibility in asphalt VOCs qualitative and quantitative analysis: Insights from laboratory studies on emission characteristics

Enhancing accuracy and reproducibility in asphalt VOCs qualitative and quantitative analysis: Insights from laboratory studies on emission characteristics

Recycled polypropylene/crystalline cellulose composites obtained using polypropylene functionalized with maleinized hyperbranched polyol polyester as compatibilizing and plasticizing agent

AbstractRecycled polypropylene (rPP)/crystalline cellulose (rPP/CC) composites are promising alternatives for reducing the detrimental environmental consequences of virgin PP. However, the incompatibility of the rPP/CC composites hinders their widespread application. In this study, PP functionalized with maleinized hyperbranched polyol polyester (PP‐g‐MHBP) was used as a compatibilizing and plasticizing agent for the rPP/CC composites. Furthermore, the effect of PP‐g‐MHBP content on the rheological, thermal, morphological, and mechanical properties of the rPP/CC composites was evaluated. The composites were prepared at a mixing speed of 50 rpm for 7 min and the PP‐g‐MHBP content was varied between 0 and 20 wt%. The torque stabilization time was less than 1 min. The activation energy of flow () decreased with increasing PP‐g‐MHBP content, with its values ranging from 0.78 × 102 to 1.42 × 102 kcal.mol−1. The flow index () followed the opposite trend with values ranging from 0.55 ± 0.0030 to 0.85 ± 0.0010. PP‐g‐MHBP enhanced the processability, thermal stability and conductivity. The crystallinity, interactions between rPP and CC, and tensile modulus of the rPP/CC composites were also enhanced. Furthermore, it reduced the agglomeration of CC particles.Highlights The torque stabilization was lowest for all composites. The composites displayed low activation energy of flow. Recycled polypropylene and crystalline cellulose exhibited good interaction. The plasticizing effect was higher than that of compatibilization. The thermal stability and mechanical properties of the composites improved.

Production of mRNA lipid nanoparticles using advanced crossflow micromixing.

Lipid nanoparticles (LNPs) play a crucial role in RNA-based therapies, and their production is generally based on nanoprecipitation and coalescence of lipids around an RNA core. This study investigated crossflow micromixing to prepare LNPs across various mixing ratios and production speeds. A range of LNPs were prepared using crossflow micromixing across production speeds of 10-500ml/min, and their physico-chemical characteristics (size, polydispersity index (PDI), zeta potential, and mRNA encapsulation), in vitro mRNA expression and in vitro efficacy (protein expression and antibody and cytokine responses). Our results demonstrate the reproducible production of mRNA-LNPs with controlled critical quality attributes, including high mRNA encapsulation from the initial screening scale through to GMP-scale production, where the same mixing ratio can be adopted across all product speeds from 30 to 500ml/min used. We confirm the applicability of stainless-steel crossflow membrane micromixing for the entire spectrum of mRNA-LNP production, ranging from initial discovery volumes to GMP-production scale.

Experimental study on the effect of mixing parameters on the rheological behaviour and micro-flocculation structure of ultrafine Portland cement slurry

Experimental study on the effect of mixing parameters on the rheological behaviour and micro-flocculation structure of ultrafine Portland cement slurry

Determination of thermal properties of grouting materials for borehole heat exchangers (BHE)

Thermal properties of grouting materials for borehole heat exchangers (BHE) are currently analysed with varying measurement methods and analysis procedures, resulting in difficulties when comparing values of different studies. This study therefore provides the first comprehensive investigation of different analysis procedures by systematically comparing the influence of the measurement method and the sample preparation on the determination of the thermal conductivity and the volumetric heat capacity. Seven dissimilar grouting materials with varying water–solid ratios (W/S) and compositions are analysed. The thermal conductivities of the materials range between 0.9 and 1.8 W m−1 K−1 (transient plane source method, TPS). The volumetric heat capacities range between 3.01 and 3.63 MJ m−3 K−1 (differential scanning calorimetry, DSC). From the findings of this study, a standardised analysis of grouting materials is provided which suggests mixing of the grouting material at a high mixing speed and sample curing under water for 28 days at room temperature. The benefits of calculating the volumetric heat capacities of grouting materials from the specific heat capacities of dry samples measured with the DSC, the water content and the bulk density are demonstrated. Furthermore, an estimation procedure of volumetric heat capacity from the W/S and suspension density with an uncertainty of smaller ± 5% is provided. Finally, this study contributes to consistency and comparability between existing and future studies on the thermal properties of grouting materials.

An Innovative Approach for Oxidative Desulfurization Advancement through High Shear Mixing: An Optimization Study on the Application of Benzothiophene.

Alternative fuels are being explored to mitigate the effects of petroleum-based fuels. Pyrolysis oil from waste tires is a promising alternative fuel; however, it contains very high concentrations of benzothiophene (BT) which are beyond the allowable sulfur limits of Taiwan and the Philippines. Mixing-assisted oxidative desulfurization (MAOD) is a method that removes sulfur from fuel oils by utilizing high-shear mixing and oxidants. In this paper, the oxidation of BT in a model fuel was studied to determine optimal process conditions. Crude Fe(VI) prepared from sludge was used as the oxidant. Using the Box-Behnken design under response surface methodology, the significance of the following independent variables was studied: mixing speed (4400-10 800 rpm), phase transfer agent (PTA) amount (100 to 300 mg), Fe(VI) concentration (400-6000 ppm), and mixing temperature (40 to 60 °C). The results from a comprehensive statistical analysis showed the increase of sulfur conversion with high levels of Fe(VI) concentrations and PTA amounts together with low levels of agitation speeds and temperatures. The BT to BT sulfone conversions from experimental runs ranged from 17% to 64%. The optimum sulfur conversion of 88% for the BT model fuel was reached at the maximum levels of Fe(VI) concentration and mixing speed, along with the minimum levels of PTA concentration and temperature. The optimal MAOD variables were applied to a high-sulfur pyrolysis oil sample, which resulted in a sulfur reduction of 55%. The produced fuel oil meets the sulfur requirements of Taiwan and the Philippines for industrial heating oils. Therefore, the findings of the study support the effectiveness of sludge-derived Fe(VI) in the MAOD of BT in the model fuel and pyrolysis oil under mild process conditions.

The exchange dynamics of biomolecular condensates.

A hallmark of biomolecular condensates formed via liquid-liquid phase separation is that they dynamically exchange material with their surroundings, and this process can be crucial to condensate function. Intuitively, the rate of exchange can be limited by the flux from the dilute phase or by the mixing speed in the dense phase. Surprisingly, a recent experiment suggests that exchange can also be limited by the dynamics at the droplet interface, implying the existence of an 'interface resistance'. Here, we first derive an analytical expression for the timescale of condensate material exchange, which clearly conveys the physical factors controlling exchange dynamics. We then utilize sticker-spacer polymer models to show that interface resistance can arise when incident molecules transiently touch the interface without entering the dense phase, i.e., the molecules 'bounce' from the interface. Our work provides insight into condensate exchange dynamics, with implications for both natural and synthetic systems.

The exchange dynamics of biomolecular condensates

A hallmark of biomolecular condensates formed via liquid-liquid phase separation is that they dynamically exchange material with their surroundings, and this process can be crucial to condensate function. Intuitively, the rate of exchange can be limited by the flux from the dilute phase or by the mixing speed in the dense phase. Surprisingly, a recent experiment suggests that exchange can also be limited by the dynamics at the droplet interface, implying the existence of an ‘interface resistance’. Here, we first derive an analytical expression for the timescale of condensate material exchange, which clearly conveys the physical factors controlling exchange dynamics. We then utilize sticker-spacer polymer models to show that interface resistance can arise when incident molecules transiently touch the interface without entering the dense phase, i.e., the molecules ‘bounce’ from the interface. Our work provides insight into condensate exchange dynamics, with implications for both natural and synthetic systems.

Study on extraction desulfurization of road-paving asphalt by deep eutectic solvents

Study on extraction desulfurization of road-paving asphalt by deep eutectic solvents