Preparation Process Parameters Research Articles

Synthesis and chromatic properties of high color performance Prx-ZrSiO4 (x = 0–0.1) yellow pigment

In this paper, high color performance Pr cation doped zircon (Pr-ZrSiO4) yellow pigment has been prepared by inorganic sol-gel method. Meanwhile, the detailed process parameters for preparation of Pr-ZrSiO4 pigment were systematically investigated. The research results indicate that the optimal process parameters are Pr-doping amount of 6 mol.%, calcination temperature of 900 °C, holding time of 2 h and Si/Zr ratio of 1.05. The synthesized Pr-ZrSiO4 pigment shows an intense yellow hue, which chromatic parameters are L* = 81.84, a* = 4.36, b* = 70.55 and C* = 70.68. Moreover, the pigment shows outstanding tinting performance for ceramic glaze, suggesting its attractive application in ceramic decoration. XPS analysis demonstrated that the Pr cations in the Pr-ZrSiO4 pigment consists of two valence states, namely trivalent and tetravalent. Finally, heterogeneously distributed behavior of Pr cations in the pigment was discovered.

Optimization of conditions for esterification of thiodiacetic acid in urine using mathematical planning for biological monitoring

Introduction. To assess the impact of the toxicants vinyl chloride (VC) and 1,2-dichloroethane (DCE) on humans, personalized biomonitoring of thiodiacetic acid (TDAA) is of most significant importance. Determination of TDAA in urine was carried out using the method of gas chromatography-mass spectrometry GC-MS. Materials and methods. Sample preparation consists of the analyte’s esterification in a biological matrix with methyl alcohol (with 10% boron trifluoride), extraction of the derivative by liquid extraction with ethyl acetate. We used an Agilent 7890A gas chromatograph with an HP-5MS capillary column and a mass-selective detector. TDAA was identified in the form of a dimethyl ester on a mass chromatogram according to the retention time and the ratio of the intensities of the registered ions. Results. To determine the rational parameters of the sample preparation process for the determination of TDAA in urine studies were carried out under the method of planning the experiment, which makes it possible to obtain the most accurate mathematical description of the processes. Optimization of the conditions for esterification of TDAA was carried out using mathematical planning, varying the temperature, process time, and the nature of the catalyst (BF3 or H2SO4). The scheduling matrix included eight experiments; the degree of conversion of TDAA served as an optimization parameter. Interpretation of the model showed that temperature makes more contribution to the formation of the degree of conversion than the processing time. The nature of the catalyst does not affect the degree of conversion. Conclusion. A mathematical model developed for optimizing the conditions for sample preparation of the biomarker of exposure to VC (TDAA) in urine, showed the contribution of three factors (reaction temperature, reaction time, catalyst nature) to the conversion rate, of which the reaction temperature makes the greatest contribution to the choice of optimal esterification conditions. The nature of the catalyst (BF3 or H2SO4) does not affect the conversion rate.

Statistical Optimization Using Response Surface Methodology for Enhanced Tensile Strength of Polyethylene/Graphene Nanocomposites

Despite having remarkable features such as low density, ease of fabrication and recyclability, linear low-density polyethylene (LLDPE) has several drawbacks like poor stiffness and low creep resistance which fortunately can be improved by incorporating with other suitable nanofillers. In this study, graphene nanoplatelets (GNPs) that are well-known for its high surface area and superior stability were selected to reinforce the polymer network of LLDPE via melt blending. During mixing processing, the rotor speed, mixing temperature and mixing time parameters are manipulated with the aids of 5-level-3-factor central composite rotatable design (CCRD) in order to determine the optimization of processing parameters in preparing LLDPE/GNPs nanocomposites. The experimental data is fitted with the statistically significant quadratic model with R2 value of 0.8601. The results showed that the tensile strength of LLDPE/GNPs nanocomposites could be extended to 24.80 MPa. The optimum processing parameters for preparation of LLDPE/GNPs nanocomposites were found to be at 101 rpm rotor speed, 139.8oC of mixing temperature and 13.2 min of mixing time, resulting in LLDPE/GNPs nanocomposites with tensile strength of 24.11 MPa. Conclusively, our study has provided a novel statistical design of experiment to obtain the optimum processing parameters in preparing LLDPE/GNPs nanocomposites.

Preparation and evaluation of self‐healing microcapsules for asphalt based on response surface optimization

AbstractThe purpose of this study is to explore the best preparation process of asphalt self‐healing microcapsules. Response surface design and single factor design were used to optimize the preparation process parameters of asphalt self‐healing microcapsules, and the prediction model of core content was established. The optimal preparation process was determined. The results of response surface design showed that the interaction among emulsifier concentration/reaction temperature, core‐shell ratio/reaction temperature, and pH/reaction temperature had significant effect on the core content of microcapsules; the microcapsules prepared by the optimal process were spherical with an average particle size of 90.19 μm. The results of thermogravimetric analysis (TGA) and heating simulation test showed that the microcapsule can delay the damage of the core in high temperature environment; the results of nanoindentation test showed that the young's modulus and hardness of the microcapsules were about 2.50 and 0.28 GPa, respectively. Finally, the improvement mechanism of self‐healing performance of asphalt by microcapsules was revealed by fluorescence microscope.

Investigation of the Properties of Heat-Protective Coatings to Improve the Performance of Products

The heat-loaded part of the combustion chamber of a liquid rocket engine are Considered. The proposed coating has several layers: an internal metal coating that contacts the part or substrate, and an external coating made of a mixture of ceramic granules and metal powder. At the same time, to obtain the initial surface for coating with the required surface layer roughness, it is proposed to use the method of sand blasting. The article analyzes possible mechanisms of material formation for "base-coating" transition zones, as well as the influence of their chemical composition on the adhesive strength of layers.. The choice of brand and combination of materials used for coating is justified. Technological modes that have been tested in production conditions when applying heat-resistant coatings to parts of modern rocket engines are proposed. The influence of technological parameters of the initial surface preparation process and the geometry of the resulting micro-relief of the substrate on the adhesion characteristics of a multilayer coating made of heat-protective materials operating in the high-temperature zone of the combustion chamber of liquid rocket engines is revealed.

Study of the effect of preparation parameters on thermal conductivity of metal oxide nanofluids using Taguchi method

The optimization of process parameters of the nanofluid preparation process for maximum stability and high heat transfer is an active and important area of research. In this work, the effect of the surfactant material, surfactant weight, and ultrasonication time are studied on distilled water-based CuO, Fe3O4, and CuO+Fe3O4 nanofluids. Taguchi L9 orthogonal array was used for the design of the experiment and 9 samples were prepared using this array. The effect of each level of process parameter on the thermal conductivity is analyzed by calculating Signal to Noise Ratio (SNR) and optimum levels of these parameters are identified. The crucial role of stability in delivering high thermal conductivity nanofluids as predicted by SNR analysis is further confirmed using Analysis of Variance (ANOVA).

Optimization of process parameters for thermal shock resistance and thermal barrier effects of 8YSZ thermal barrier coatings through orthogonal test

The thermal shock resistance and the thermal barrier effects are the key indices for thermal barrier coating (TBC) performances. The performance optimization of 7∼8 wt. % Y2O3 stabilized ZrO2 (7∼8YSZ) TBCs is a research focus at present. In this work, an orthogonal test was employed to study the relationship between parameters and performances and match process parameters for TBCs preparation. The scanning electron microscope was employed to analyze the microstructures of 8YSZ TBCs. The thermal shock resistance test and thermal barrier effect test were conducted to judge the performances of 8YSZ TBCs. It was found that the process factor had the greatest influences on porosity and elastic modulus was spraying distance and the factor had the greatest influence on bond strength was spraying power. The selected parameters were a spraying distance of 90 mm, an argon flow of 32 L/min, a hydrogen flow of 8 L/min, an electric current of 550 A, a spraying power of 35 kW, a feeding rate of 45 g/min, and a substrate preheating temperature of 373 K. The thermal shock life was ∼100 times under 1173∼298 K, and the thermal barrier temperature of optimized 8YSZ TBCs with thicknesses of 250 and 300 µm was ∼90 and ∼130 K under 1473 K, respectively. Through a comparative study, both thermal shock resistance and thermal barrier effects of 8YSZ TBCs were improved after process parameters’ optimization conducted by this method.

Preparation and Performance Index Test of Continuous Glass Fiber Reinforced Filament- Polylactic Acid for 3D Printer

The “independent extrusion” 3D printer of Continuous Fiber Reinforced Thermoplastic Composites (CFRTPC) is gradually recognized by the market, but it cannot be widely used due to the limitations of printing materials. This paper focuses on the development of Continuous Glass Fiber Reinforced Filament- Polylactic Acid (CGFRF-PLA) for “independent extrusion” printing. The preparation device of Continuous Fiber Reinforced Filament (CFRF) was designed, and the effects of preparation process parameters such as temperature, speed and coupling agent on the performance index of CGFRF-PLA were studied by experiments, the best preparation process parameters were determined.

Superior corrosion resistance-dependent laser energy density in (CoCrFeNi)95Nb5 high entropy alloy coating fabricated by laser cladding

(CoCrFeNi)95Nb5 high entropy alloy (HEA) coatings were successfully fabricated on a substrate of Q235 steel by laser cladding technology. These (CoCrFeNi)95Nb5 HEA coatings possess excellent properties, particularly corrosion resistance, which is clearly superior to that of some typical bulk HEA and common engineering alloys. In order to obtain appropriate laser cladding preparation process parameters, the effects of laser energy density on the microstructure, microhardness, and corrosion resistance of (CoCrFeNi)95Nb5 HEA coating were closely studied. Results showed that as the laser energy density increases, precipitation of the Laves phase in (CoCrFeNi)95Nb5 HEA coating gradually decreases, and diffusion of the Fe element in the substrate intensifies, affecting the integrity of the (CoCrFeNi)95Nb5 HEA. This decreases the microhardness of (CoCrFeNi)95Nb5 HEA coatings. Moreover, the relative content of Cr2O3, Cr(OH)3, and Nb2O5 in the surface passive film of the coating decreases with increasing energy density, causing corrosion resistance to decrease. This study demonstrates the controllability of a high-performance HEA coating using laser cladding technology, which has significance for the laser cladding preparation of other CoCrFeNi-system HEA coatings.

Finger millet-based staple beverages consumed by the Gadaba ethnic community of Odisha, India: Preparation and nutritive characteristics

Abstract. Mishra AK, Bajpai R, Swain A. 2021. Finger millet-based staple beverages consumed by the Gadaba ethnic community of Odisha, India: Preparation and nutritive characteristics. Biodiversitas 22: 2737-2742. The indigenous food and beverages reflect the acquaintance of ethnic population to local environmental settings. Development of diet structure includes diversities in food and beverages depend on the ethnic knowledge they perceive from their ancestors as well as from the environmental determinants. The Gadaba ethnic community being native to the southern part of Odisha state in India, developed the art to sustain them through rain-fed agricultural crops like finger millet and upland rice. These traditional non-hybrid crops give different dimensions to their food and beverage structure. In this case, the study focussed on finger millet-based staple beverages consumed by Gadaba ethnic community of this region. The effort is given to discuss the complete indigenous preparation process and nutritional parameters concerning two indigenous indispensable fermented beverages named Landa and Pej. The nutritional analysis of these beverages proved it to be a promising diet structure for sustainability.

Study on Coating Material and Preparation Technology of Aluminum Alloy Tube by Low Temperature Self-Propagating Molding

Low temperature self-propagating forming coating material system for aluminum alloy cylinder parts was designed with Al, Fe2O3, Mo, Cu, Ni and Ti powders as raw materials. Low temperature self-propagating wear-resistant coating was prepared on the inner wall of aluminum alloy cylinder parts by thermal spraying ignition condensation centrifugal self-propagating fusion technology. XRD, DSC and SEM were used to study the microstructure, thermodynamic properties and cross-section morphology of the coating after thermal reaction of four kinds of low-temperature self-propagating materials with different proportions. The preparation process parameters of the coating were optimized by orthogonal test, including the amount of coating, the rotation speed of self-propagating centrifuge and the reaction time of self-propagating coating. The results show that the addition of Si, Mo and Zn powders in the four low temperature self-propagating powder systems can reduce the occurrence temperature of aluminothermic reaction; the optimal process parameters for coating preparation are rotational speed of 2000r/min, powder filling amount of 0.9g/cm3 and rotational reaction time of 16S.The results show that the coating with 20wt.% Al, 60wt.% Fe2O3, 12wt.% Si, 4wt.% Mo and 4wt.% Zn has better density and interface adhesion.

Preparation and Characterization of Microcrystalline Wax/Epoxy Resin Microcapsules for Self-Healing of Cementitious Materials.

Self-healing of cracks in cementitious materials using healing agents encapsulated in microcapsules is an intelligent and effective method. In this study, microcapsules were prepared by the melt–dispersion–condensation method using microcrystalline wax as the shell and E-51 epoxy resin as the healing agent. The effects of preparation process parameters and microcrystalline wax/E-51 epoxy resin weight ratio on the core content, particle size distribution, thermal properties, morphology, and chemical composition of microcapsules were investigated. The results indicated that the optimal parameters of the microcapsule were microcrystalline wax/E-51 epoxy resin weight ratio of 1:1.2, stirring speed of 900 rpm, and preparation temperature of 105 °C. The effects of microcapsules on pore size distribution, pore structure, mechanical properties, permeability, and ultrasonic amplitude of mortar were determined, and the self-healing ability of mortar with different contents of microcapsules was evaluated. The optimal content of microcapsules in mortars was 4% of the cement weight, and the surface cracks of mortar containing microcapsules with an initial width of 0.28 mm were self-healed within three days, indicating that microcapsules have excellent self-healing ability for cementitious materials.

Response Surface Methodology for Optimizing the Preparation Process of Cellulose Acetate/Polylactic Acid Nonwoven Surgical Gown Material

In view of the problems that traditional woven surgical gowns are prone to cross infection in blocking blood and liquid spillage, cellulose acetate (CA)/polylactic acid (PLA) nonwoven materials were prepared to improve the functional requirements of surgical materials in combination with the rapidly developing green fibers. Fiber mixing ratio, fiber web areal weight and water jet pressure were selected to optimize the preparation process of cellulose acetate/polylactic acid (CA/PLA) nonwoven materials with moisture permeability and filtration efficiency. The results showed that the fiber mixing ratio was 49:51, and the fiber web areal weight was 130 g/m2, and the water jet pressure was 7 MPa. Under this process, moisture permeability is 5240.86 g/(m2·h), and the filtration efficiency is 38.12 %, which is close to the theoretical value. It shows that the response surface method has practical application value, indicating that the response surface method has practical application value, and can provide a theoretical basis for the preparation process parameters of barrier and comfort nonwoven surgical gowns at the same time.

USING THE BOX–BEHNKEN EXPERIMENTAL DESIGN DEVELOPMENT OF GASTRORETENTIVE MUCOADHESIVE MICROSPHERES OF SIMVASTATIN BY SPRAY DRYING METHOD

Simvastatin is an antihyper-lipidemic drug which inhibits HMG-CoA reductase, interrupting cholesterol synthesis. It is poorly water soluble drug having very low bioavailability (5%). It is having better absorption in upper gastro intestinal tract. Due to lower bioavailability and short biological half-life simvastatin is prescribed 2-3 times a day which leads to lower patient compliance. The aim of the present work was to prepare controlled release microspheres which and retained in the gastric area by adhering to the mucosal membrane for longer period of time. It was a also proposed to design and optimize the formulation and process parameters for preparation of gastroretentive simvastatin microspheres using spray drying technique. The major problem associated with oral drug delivery is ineffective absorption and low bioavailability because drugs having narrow absorption window. Simvastatin microspheres was prepared using polymer HPMC K4M as carrier polymer and Eudragit RSPO were prepared using spray drying technique. The in vitro evaluation of mucoadhesive property of simvastatin microspheres was done on goat intestinal mucosa which showed strong mucoadhesion of 85% up to 6 hours. The in vitro drug release studies of microspheres were performed in 0.01 M sodium phosphate containing 0.5% SLS using syringe pump for 8 h.

The Numerical and Experimental Investigation of Particle Size Distribution Produced by an Electrical Discharge Process.

The vague influence of thermal action of electrical discharge on size distribution of metallic powders hinders the adjustability of powder quality. Due to the small gap, short discharge on-time, uncertain discharge point, and strong light interference, direct observation of preparation is difficult to carry out. Herein, the multi-physics coupling finite element method (FEM) was applied to numerically investigate the relationship between size distribution and thermal action. Through modeling of thermal transformation and heat distribution on the surface of electrode, temperature of the electrode is found to be decided by the latent heat and the distribution of heat point obeys the normal distribution, which corresponds with experimental results. Finally, the vapor film to droplet fragmentation theory was proposed to explain the phenomenon of normal distribution. The research results provide theoretical support for the preparation of metallic powder by electrical discharge, and also play a guiding role in optimizing the process parameters in the actual preparation process to tune the size distribution.

ИНТЕГРАЛЬНАЯ ПРОМЫШЛЕННАЯ СИСТЕМА УТИЛИЗАЦИИ ТЕХНОГЕННЫХ ОТХОДОВ ГОРНЫХ ПРЕДПРИЯТИЙ, ТЕРРИТОРИАЛЬНО ОБЪЕДИНЁННЫХ

At present, there is a need for import substitution (including technologies) in Russia, so the manuals development and regulation of the best available technologies (BAT, Best Available Technologies) are underway. BAT manuals, for example, for the mining industry are basic documents that provide a step-by-step description of BAT, ensuring compliance with obligatory environmental performance indicators. However, these are isolated, unrelated short versions that do not allow for a comprehensive solution to the problems of available mineral resources (AMR) deficit and reduction of environmental degradation risks. To solve the above problems, it is necessary to develop an integrated system for the disposal of man-made waste from mining and mining processing enterprises, geographically united, in order to identify, select effective technologies from alternative proposals and their implementation. The purpose of the study is to develop an integrated system for the disposal of technogenic waste from mining enterprises that are geographically united. Research objectives: study of waste disposal facilities included in the State Register of the Russian Federation; development of a technological scheme for the joint processing of technogenic raw materials of various types; development of a stationary cuvette for year-round heap leaching (KV) of gold in the cryolithozone; conducting experimental studies of KV gold with an effective reagent complex; development of an integrated industrial system for the disposal of technogenic waste from mining enterprises, geographically united; development of alternative options for the production of gold in order to choose an effective technology, depending on the nature of gold mineralization and the form of finding the precious metal in man-made waste. The authors have scientifically substantiated and developed the variants of the integrated industrial system of the closed cycle, using mobile operatively tunable flow lines consisting of independent modules for technogenic waste processing of Darasunsky mine - the enterprise for extraction and ore enrichment of Darasunsky, Teremkinsky and Talatuysky gold deposits (Tungokochensky and Transbaikal regions). According to the cadastre of technogenic accumulations, the sources of mine wastes with the volume of 14410.2 thousand tons are waste dumps of overburden rocks and poor ores, technogenic raw materials of tailing dumps, other accumulations of technogenic raw materials. Experimental studies of gold heap leaching (HL) by the reagent complex including solutions of sodium cyanide and hydrogen peroxide in the ratio – H2O2:NaCN=10:1 have been carried out. Optimal technological parameters of ore preparation and gold leaching process from waste pelletized granules of different types at a ratio of 1:0.5:0: 5 are established, accordingly, out of balance ores of the Talatuy deposit (βAu – 0.7 g/t), underlaid tailings (βAu – 1.45 g/t) and tailings of the current ore processing of Darasunsky gold concentration plant (GCP) (βAu – 0.3 g/t). Gold recovery has amounted 87.1%. In order to implement year-round heap leaching in the cryolite zone, a deepened concrete ditch with multilayer shielding of the upper surface of the stack by injecting warm air through specially equipped perforated vinyl pipes has been installed and a special pelletized granules placement has been carried out. After neutralization KV waste has been proposed to be used in the road construction industry. The industrial system developed by the authors makes it possible to carry out all year round KV, to commercialize utilization of man-caused deposits, both for a long conservation period and the current production and processing, to improve the environmental safety of the city-forming enterprises of the mining cluster. Alternative options are proposed in order to choose an effective technology

Rapid Prototyping of Micropillars using Digital Light Process 3D Printing Technique

In this paper, we discuss a technique to fabricate a three-dimensional (3D) printed micropillars structure of microfluidic system. The developed system consists of microchannels, chambers, and micropillars. The creation of arrays of pillars were the focus of the study. The structure is fabricated using a 3D printing technique called Digital Light Process (DLP). In this paper, we examine the potential use of the 3D printing approaches for the fabrication of microfilter and micromixer devices integrated with microfluidic channels. Our 3D printing process shows that micropillars with diameters between 200 and 400 μm can be fabricated using a DLP 3D printer machine by optimizing the preparation process and post processing parameters. Later, SEM analysis shows that micropillars with high aspect ratio and straight side wall were achieved. The DLP 3D printer is the most suitable and reliable technique that can produce the smallest dimension compared to other types of 3D printer that shows a promising method for the rapid prototyping of microfluidic devices for biomedical application.

Optimization of process parameters for preparation of powdered activated coke to achieve maximum SO2 adsorption using response surface methodology

Powdered activated coke (PAC) is a good adsorbent of SO2, but its adsorption capacity is affected by many factors in the preparation process. To prepare the PAC with a high SO2 adsorption capacity using JJ-coal under flue gas atmosphere, six parameters (oxygen-coal equivalent ratio, reaction temperature, reaction time, O2 concentration, CO2 concentration, and H2O concentration) were screened and optimized using the response surface methodology (RSM). The results of factor screening experiment show that reaction temperature, O2 concentration, and H2O (g) concentration are the significant factors. Then, a quadratic polynomial regression model between the significant factors and SO2 adsorption capacity was established using the central composite design (CCD). The model optimization results indicate that when reaction temperature is 904.74°C, O2 concentration is 4.67%,H2O concentration is 27.98%, the PAC (PAC-OP) prepared had a higher SO2 adsorption capacity of 68.15 mg/g while its SO2 adsorption capacity from a validation experiment is 68.82 mg/g, and the error with the optimal value is 0.98%. Compared to two typical commercial activated cokes (ACs), PAC-OP has relatively more developed pore structures, and its SBET and Vtot are 349 m2/g and 0.1475 cm3/g, significantly higher than the 186 m2/g and 0.1041 cm3/g of AC1, and the 132 m2/g and 0.0768 cm3/g of AC2. Besides, it also has abundant oxygen-containing functional groups, its surface O content being 12.09%, higher than the 10.42% of AC1 and 10.49% of AC2. Inevitably, the SO2 adsorption capacity of PAC-OP is also significantly higher than that of both AC1 and AC2, which is 68.82 mg/g versus 32.53 mg/g and 24.79 mg/g, respectively.

Design and synthesis of PVDF-cloisite-30B nanocomposite fibers for energy harvesting applications

Polymer nanofibers of PVDF/Cloisite-30B clay composites were synthesized by far field electrospinning technique. Taguchi's L9 orthogonal array was used to study the effect of process parameters in electrospinning. Different polymer composite films were prepared with various composition and process parameters. The best result obtained with highest β-phase crystallinity with 89.7% with average fiber diameter of 79 nm. Further piezoelectric property of nanofiber composite was measured by oscilloscope actuated through a mechanical cam driven by a D C motor at different speed 500, 1000 and 1500 rpm respectively. Grey relation analysis was performed to identify the most significant process parameters for preparation of uniform nanofibers. Grey relation grading for response parameters was ranked 1 for highest β-phase crystallinity among the studied composites. The PVDF composite sample with 3% cloisite-30B showed high instantaneous voltage of 4.4V with applied voltage of 22 kV and collector plate distance of 12 cm.

Study on Denitration Performance of Solid Waste Blast Furnace Slag Catalysts under Different Preparation Processes.

In this article, blast furnace slag, a high-yield industrial solid waste, was taken as the research object and it was used as the main material. Bentonite was used as the binder, and water was added to shape the blast furnace slag into a small column. The denitration catalyst was prepared using different methods, its denitration performances were compared and analyzed, and the best preparation method and process parameters were screened. Results showed that bentonite will clearly improve denitration performance, and 4:1 blast furnace slag and bentonite was selected as the molding ratio to reduce the effect of bentonite on its performance, combined with the hardness and surface adhesion of the prepared carrier. Separately, the catalysts were prepared using citric acid impregnation, hydrothermal decomposition, and mixing method, and active Mn was loaded. Among them, the hydrothermal decomposition method cannot completely decompose in a closed kettle, resulting in a lower denitration performance. The catalyst prepared using the mixing method is superior to that prepared using the impregnation method because the active component prepared by the former was more uniformly dispersed, and simple and easy to operate, which can meet the needs of the excess denitration catalysts of small enterprises.