Optimal Parameters Research Articles

Endoscopic ultrasound-guided fine needle biopsy using macroscopic on-site evaluation technique reduces the number passes yet maintains a high diagnostic accuracy: A randomized study.

Although rapid on-site cytological evaluation (ROSE) for endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) may increase diagnostic yield, it is not widely available. Macroscopic on-site evaluation (MOSE) is an alternative modality although it is not standardized for EUS-guided fine-needle biopsy (FNB). We evaluated diagnostic performance of MOSE compared with conventional technique of EUS-TA using core biopsy needle. Consecutive patients undergoing EUS-FNA for solid lesions were randomized to MOSE or conventional arms. The primary and secondary outcome measures were diagnostic accuracy, diagnostic yield, sensitivity, specificity, positive and negative predictive values, and the number of passes, respectively. The optimum parameters for macroscopic visible core (MVC, i.e., length, number) by MOSE to achieve accurate diagnosis were evaluated. Ninety-six patients (48 conventional and 48 MOSE) were enrolled. Mean lesion size was larger in MOSE arm (32.67±7.22 vs 29.31±6.98mm, P=0.023). Diagnostic accuracy (95.8% vs 91.6%), diagnostic yield (97.9% vs 95.8%), procedure duration, and adverse events of the two methods were similar. Median number of passes with MOSE was less (2 vs 3 P=0.000). Area under the receiver operating characteristic curve showed that with MOSE, obtaining a total MVC length of 11.5mm had 93.3% sensitivity, and 2.5 MVC cores (each 4mm) had 86.7% sensitivity for malignancy diagnosis. EUS-FNB with MOSE, a simple reliable technique, can achieve a high and comparable diagnostic accuracy with lesser number of passes. Obtaining longer length and greater number of MVC increase the sensitivity to diagnose malignancy with MOSE.

Study on dynamic recrystallization and precipitation behavior of hot compressed Al-20Zn-0.5Mg-0.5Sc alloy

The dynamic recrystallization (DRX) behavior of the Al-20Zn-0.5Mg-0.5Sc alloy was investigated under specific conditions using a Gleeble-3500 thermal simulator. The resultant grain size, recrystallization degree and precipitated phases were studied. The results indicate that the sensitivity of DRX grain size is highly affected by temperature, feebly influenced by strain and intermediately affected by strain rate. The DRX grains are grown by an average of 3.49 μm with increasing temperature. The DRX behavior is sensitive to temperature, strain and strain rate, resulting in changes in average grain size, percentage of HAGBs and degree of recrystallization under different parameters. At 400 ℃ / 40 % / 0.1 s−1, the average grain size is refined to 12.90 μm, and the corresponding HAGBs and recrystallization degree are approximately 46.2 % and 34.3 %, respectively. The Al3Sc, Zn and η (MgZn2) phases are precipitated in the hot-compressed alloy. The Al3Sc phase promotes the precipitation of the Zn and η phases. The size, amount and morphology of Al3Sc, Zn and η phases at different parameters have an important influence on the movement of dislocations and nucleation of grains, which leads to changes in DRX grain size and the degree of recrystallization. The fine precipitated phase particles Al3Sc and η inhibit the growth of recrystallized grain by pinning grain boundaries and exerting a blocking force on dislocations. Dynamic precipitation is the dominant mechanism for the changes in DRX grain size and degree of recrystallization. To achieve the refined grains and homogeneous microstructures, the optimum parameters are recommended as 400 ℃, 0.1 s−1 and 50 %.

Experimental Determination of Influences of Static Eccentricities on the Structural Dynamic Behavior of a Permanent Magnet Synchronous Machine

In electrified vehicles, the masking noise behavior of internal combustion engines is absent, making the tonal excitation of the electric machine particularly noticeable in vehicle acoustics, which is perceived as disturbing by consumers. Due to manufacturing tolerances, the tonal NVH characteristics of the electric machine are significantly influenced at wide frequency ranges. This paper presents a systematic exploration of the influence of static eccentricity as one manufacturing tolerance on the NVH behavior of Permanent Magnet Synchronous Machines (PMSMs). The study utilizes a novel test bench setup enabling isolated variations in static eccentricity of up to 0.2 mm in one PMSM. Comparative analysis of acceleration signals reveals significant variations in the dominance of excitation orders with different eccentricity states, impacting critical operating points and dominant frequency rages of the electric machine. Despite experimentation, no linear correlation is observed between increased eccentricity and changes in acceleration behavior. Manufacturing eccentricity and deviations in rotor magnetization are discussed as potential contributors to the observed effects. The findings emphasize static eccentricity as a critical parameter in NVH optimization, particularly in electrified powertrains. However, the results indicate that further investigations are needed to explore the influence of eccentricities and magnetization deviations on NVH behavior comprehensively.

One-Bath One-Step Dyeing of Polyester/Cotton Blend Fabrics Through Lipase Enzyme Surface Modification

ABSTRACT In this study, based on lipase enzyme surface modification, low-temperature dyeing of polyester/cotton fabric with reactive dyes was researched to achieve a one-bath one-step dyeing method. The Box-Behnken method was used to conduct the experiment and determine factors. For surface modification, lipase concentration, reaction time, and treatment temperature were considered, whereas for the dyeing process, reactive dye concentration, dyeing time, and dyeing temperature were taken into account to measure color strength. A treatment temperature of 30°C, a lipase enzyme concentration of 14 w/v %, and a treatment time of 50 min were shown to be ideal or optimum surface treatment parameters for lipase enzyme surface modification. The optimal or ideal conditions for the dyeing process were a reactive dye concentration of 2.13 w/v%, dyeing time of 50 min, and dyeing temperature of 66°C, giving a color strength value of 3.02. Lipase enzyme-modified polyester/cotton (p/c) blend fabrics provide color fastness that is all over grades 3–4, including washing fastness, rubbing fastness, perspiration fastness, and light fastness. The outcomes raise the prospect of developing a new technique for dying polyester/cotton blend fabric in a single bath using a single dye class that is typically employed for dying textiles made of cellulosic material.

Effective Removal of Selenium from Aqueous Solution using Iron-modified Dolochar: A Comprehensive Study and Machine Learning Predictive Analysis

Selenium (Se) is an essential micronutrient for human beings, but excess concentration can lead to many health issues and degrade the ecosystem. This study focuses on the removal of selenium from an aqueous solution using iron-doped dolochar. SEM, EDX, BET, XRD, FTIR, and Pzpc were conducted to determine the surface characteristics of iron-doped dolochar (FeD). The characterization of the adsorbent gave an insight into surface morphology, surface area (100 m2/g), average pore diameter (3.9 nm), and surface composition, which contributed to the Se adsorption. The pHzpc of the iron-doped adsorbent surface was found to be 7.02, which provided a broad range for effective Se adsorption. To detect the optimum parameters, the parametric influence on removal efficiency was conducted by varying pH, dosages, contact time, and initial concentration. The experiment achieved maximum selenium removal, ∼98 %, at low concentration, 10 g/L dosage, and low pH (2) within 90 min at room temperature. It fits the Langmuir better than the Freundlich isotherm (R2 = 0.99), indicating monolayer adsorption. It fitted well with pseudo-second-order kinetics. The experiment is a spontaneous, endothermic (ΔH0 = 9.22 kJ/mol) and high randomness (ΔS0 = 45.37 kJ/mol) suggested by thermodynamic study. The adsorption was influenced by competing ions as follows: phosphate > sulfate > nitrate > manganese > aluminum > zinc > iron. A regression learner tool was used to compare different models using the experimental data that showed the best fit with the Gaussian Process Regression with RMSE = 0.246, MSE = 0.061, and R2 = 0.99. Thus, it can be concluded that FeD is preferred as a better adsorbent for selenium removal from aqueous solutions and could produce 35.5% ROI, 21.5% IRR, and 24.59% BEP on FeD production.

Chromium (III) ion determination and speciation in honey & hardaliye samples using magnetic solid-phase extraction and FAAS

ABSTRACT Cr (III) is an essential element for maintaining glucose, lipid, and protein metabolism in mammals. Removal/recovery of such heavy metals is crucial. For this purpose, dendrimer-based novel magnetic nanoparticles to enrich Cr (III) were synthesized and characterized by spectroscopic methods such as SEM-EDX, TEM, FT-IR, XRD, and VSM. The optimum parameters such as pH, eluent type-concentration, adsorbent amount, and time, which are important in the recovery of Cr (III) with solid magnetic-based nanoparticles (MNPs), were determined by flame atomic absorption spectroscopy. After the enrichment of Cr (III) with MNPs, the device’s detection power enhancements were increased by 8653 ± 145 times. The optimum conditions obtained for Cr (III) ions with MNPs were successfully applied to water, honey, and hardaliye samples. Furthermore, the reusability results of the MNPs were determined to be approximately 99% for Cr (III) up to the 10th use.

Study on the Dispersion Characteristics of Coal Complex Resistivity under the Effect of Liquid Nitrogen Cyclic Freeze-Thaw and Evaluation of Permeability Enhancement.

The effect of liquid nitrogen freeze-thaw fracturing on coal seams can be potentially evaluated by the complex resistivity method. The real part (Reρ) and the imaginary part (Imρ) of the complex resistivity and permeability of coal were determined under different cycle times and in different bedding directions. The reason for permeability enhancement was discussed, and the dispersion mechanism of complex resistivity during cyclic freeze-thaw fracturing was analyzed. The results indicated that (1) the complex resistivity parameters have a good response to the cycle times; Reρ, |Imρ|, and the dispersion degree (α) are positively correlated with cycle time; the fully polarized frequency (f p) of Reρ, the characteristic frequency (f c) of Imρ, and variation are negatively correlated with cycle time. (2) The difference in complex resistivity parameters between the vertical bedding direction and the parallel bedding direction is significant, and the difference in electrical properties of the bedding structure continuously decreases with the increase in cycle time. (3) Under the effect of liquid nitrogen cyclic freeze-thaw, a complex network of fractures in coal is formed, the anisotropic characteristics of coal are weakened, and effective conductive channels are damaged. The peak frost heave force decreases exponentially with the increase in cycle time, and the difference in bedding electrical properties gradually disappears. (4) Comparing the inversion degree of measured data with three conductive models, ρ0 and τ are selected as the optimum parameters for evaluating the effect of liquid nitrogen cyclic freeze-thaw. A logarithmic permeability evaluation model is constructed based on ρ0 and τ. This work provides a new perspective based on electrical detection for evaluating the permeability enhancement of coal during liquid nitrogen cyclic freeze-thaw.

Establishing a process route for additive manufacturing of NiCu-based Alloy 400: an alignment of gas atomization, laser powder bed fusion, and design of experiments

Alloy 400 is a corrosion-resistant, NiCu-based material which is used in numerous industrial applications, especially in marine environments and the high-temperature chemical industry. As conventional manufacturing limits geometrical complexity, additive manufacturing (AM) of the present alloy system promises great potential. For this purpose, a robust process chain, consisting of powder production via gas atomization and a design of experiment (DoE) approach for laser powder bed fusion (LPBF), was developed. With a narrow particle size distribution, powders were found to be spherical, flowable, consistent in chemical composition, and, hence, generally applicable to the LPBF process. Copper segregations at grain boundaries were clearly detected in powders. For printed parts instead, low-intensity micro-segregations at cell walls were discovered, being correlated with the iterative thermal stress applied to solidified melt-pool-near grains during layer-by-layer manufacturing. For the production of nearly defect-free LPBF structures, DoE suggested a single optimum parameter set instead of a broad energy density range. The latter key figure was found to be misleading in terms of part densities, making it an outdated tool in modern, software-based process parameter optimization. On the microscale, printed parts showed an orientation of melt pools along the build direction with a slight crystallographic [101] texture. Micro-dendritic structures were detected on the nanoscale being intersected by a high number of dislocations. Checked against hot-extruded reference material, the LPBF variant performed better in terms of strength while lacking in ductility, being attributed to a finer grain structure and residual porosity, respectively.

Effect of PGV/PGA ratio on seismic-induced vibrations of structures equipped with parallel tuned mass dampers considering SSI

Tuned mass damper is one of the effective methods used to reduce dynamic loads in structures under the influence of environmental loads such as earthquakes, wind, and traffic loads. In the current TMD design, the fixed base approach is mostly considered when determining the dynamic properties of the structure. However, in cases where the structure-soil interaction (SSI) is important, the frequency values of the structure are significantly different from those obtained for the fixed foundation approach. This situation negatively affects the performance of TMD operating in a narrow frequency range. Therefore, using a control system consisting of multiple TMDs connected in parallel (MTMD) instead of a single TMD may be a promising solution for the control of structural vibrations. In this study, a parameter design and efficiency assessment of MTMD for reducing the seismic responses of the structure considering SSI is studied. The particle swarm optimization (PSO) algorithm is adopted to obtain the optimum parameters (i.e., damping ratio, frequency ratio, and frequency bandwidth) of the MTMD. The effects of different support conditions, number of TMD units, and peak ground velocity (PGV) / peak ground acceleration (PGA) ratio on the performance of MTMD are also evaluated comprehensively. The dynamic responses of the structure are obtained under 42 near -fault ground motions from the time history analysis. The results reveal that ground motions with low PGV/PGA ratio can significantly increase the responses of the structure for both with and without SSI cases. Moreover, it has been observed that optimized TMDs placed parallel to the top floor of the structure are effective in reducing the seismic responses of a ten-story building considering SSI.

Optimization of the handling behaviour of an electric car by adjusting the kinematic gains of suspension

Abstract In this paper, within the scope of development of an electric car on a vehicle platform that is borned as internal combustion engine is presented. The vehicle dynamics behaviour changes due to the change of weight distribution and centre of gravity. Replacing the internal combustion engine with an electric motor, plus the addition of the battery moves the center of gravity towards the rear of the vehicle. Due to the increase in the rear axle load, the tendency of the vehicle to oversteer increases. To overcome this phenomenon, the rear suspension kinematic gains (camber, toe change due to vertical movement of the wheel) are adjusted thanks to the multi-link suspension. In the fist part of the study the platform is measured and Admas Car model is correlated depends on measured handling metrics. Subsequently, centre of gravity changes are applied to the verified Adams Car model. Also main platform handling metrics is defined as design targets and rear axle kinematic gains are defined as design parameters. A design of experiments (DOE)-based optimization study was performed via Adams®/Insight commercial software to achieve required handling metrics which satisfy design targets. Kinematic gains of the suspension system is analyzed via Adams car and sensitivity deepens on harpoints is determined. Design space for hardpoints is determined depends on mechanical design. The lowest and highest points are determined on the x, y and z axis and experiment list are designed according to DOE. Maneuvers that are for measuring the handling metrics are performed one after the other by changing the parameters according to the boundary conditions comes from DOE. A regression mathematical model is obtained and optimum parameters are calculated for the handling behaviour optimisation. Optimum parameters are applied on the Adams Car model again and handling manoeuvres are repeated. Results show that, although weight distribution changes, handling behaviours remain the same as based platform.

Evaluation of Surface Quality and Productivity in Conventional Milling of Copper Beryllium Using Minimum Quantity Lubrication

Copper Beryllium (C17200) has ideal physical and mechanical properties of high fatigue strength, thermal conductivity, and hardness, making the alloy ideal for various high-reliability applications in aerospace, producing inserts and tooling for hazardous environments. However, surface quality and productivity challenges are prominent when processing the alloy due to its properties. This study evaluates the surface quality and productivity in end-milling of Copper Beryllium by analyzing the effects of feed rate, minimum quantity lubrication (MQL) flow rate, and cutting depth on surface roughness (Ra) and material removal rate (MRR). The experiment was designed using the Box-Behnken design, and the samples were machined on a CNC milling machine. The results showed that the MQL flow rate was significant to surface roughness, while the cutting depth was significant to MRR. The optimum parameters were determined as a feed rate of – 60 mm/min, an MQL flow rate of – 80 ml/hr., and a cutting depth of – 0.511 mm, which yielded a surface roughness of 0.12 µm and MRR of 10.19 g/min. The study's novelty is that it considers MQL flow using vegetable oil-based cutting fluid (CF) as an input parameter in machining, offering insight into eco-friendly and cost-effective machining practices. Finally, the significance of the study lies in investigating the machinability of Cu-Be alloy material, addressing challenges related to surface quality and productivity during milling operation.

Optimisation of the Encapsulation of Grape Pomace Extract by Spray Drying Using Goat Whey Protein as a Coating Material

The aim of this research was to determine the optimal conditions for the process of the microencapsulation of phenol-rich grape pomace extract (GPE) using spray drying and goat whey protein (GW) as a coating. The encapsulation was carried out with the aim of protecting the original bioactive components extracted from grape pomace to ensure their stability and protection from external agents, as well as antioxidant activity, during the conversion of the liquid extract into powder and during storage. Using the response surface methodology, an inlet air temperature of 173.5 °C, a GW ratio of 2.5 and a flow rate of 7 mL/min were determined as optimum process parameters. Under these conditions, a high yield (85.2%) and encapsulation efficiency (95.5%) were achieved with a satisfactorily low moisture content in the product (<5%). The amount of coating had the greatest influence on the MC properties. GW showed a more pronounced stabilising effect on the phenolic compounds in GPE during a longer storage period compared to anthocyanins. The results obtained indicate the potential of GW as a coating and are an example of the possible upcycling of GPE and GW, which can lead to a high-quality product that can be a functional ingredient.

Green approach for fabricating hybrids of food waste-derived biochar/zinc oxide for effective degradation of bromothymol blue dye in a photocatalysis/persulfate activation system

This study presents novel composites of biochar (BC) derived from spinach stalks and zinc oxide (ZnO) synthesized from water hyacinth to be used for the first time in a hybrid system for activating persulfate (PS) with photocatalysis for the degradation of bromothymol blue (BTB) dye. The BC/ZnO composites were characterized using innovative techniques. BC/ZnO (2:1) showed the highest photocatalytic performance and BC/ZnO (2:1)@(PS + light) system attained BTB degradation efficiency of 89.47% within 120 min. The optimum operating parameters were determined as an initial BTB concentration of 17.1 mg/L, a catalyst dosage of 0.7 g/L, and a persulfate initial concentration of 8.878 mM, achieving a BTB removal efficiency of 99.34%. The catalyst showed excellent stability over five consecutive runs. Sulfate radicals were the predominant radicals involved in the degradation of BTB. BC/ZnO (2:1)@(PS + light) system could degrade 88.52%, 84.64%, 81.5%, and 77.53% of methylene blue, methyl red, methyl orange, and Congo red, respectively. Further, the BC/ZnO (2:1)@(PS + light) system effectively activated PS to eliminate 97.49% of BTB and 85.12% of dissolved organic carbon in real industrial effluents from the textile industry. The proposed degradation system has the potential to efficiently purify industrial effluents which facilitates the large-scale application of this technique.

Reuse and Recovery of Water from Industrial Textile Dyeing Effluent Using High-Performance Electrodes Continuous Flow Electrocoagulation Reactor

The dye effluents released from the textile and printing industries contain strong colorants, inorganic salts, and other toxic compounds. The conventional coagulation technique of dye effluent treatment is plagued with issues of low removal rate of color, generation of large quantities of sludge, and toxic end-products. Recently electrocoagulation technique gained immense attention due to its high efficiency. This technique involves the dissolution of the sacrificial anodes to provide an active metal hydroxide as a strong coagulant that destabilizes the pollutants and removes them by precipitation or flocculation. This study is about the efficiency of the electrocoagulation process using titanium coated - aluminum and mild steel electrodes to treat industrial dye wastewater. Effects of parameters such as current density & initial dye concentration were investigated. It was observed that, for the same current density, electrode consumption was higher with TiO2/Al electrode than with mild steel electrode, resulting in more color removal efficiency (CRE) using TiO2/Al electrode. The settling rate of the flocs was higher in the rector having TiO2/Al electrode at the 100 mL with current density (2.5 mL.min-1 to 5.3 mL.min-1), while in the reactor with mild steel electrode, the settling rate was very less. The results showed that dye removal was 95.11% and 92.1% for mild steel and titanium-coated electrodes, respectively. It was observed that 50 % of Aluminum was removed from the treated effluent after the final stage of filtration. Based on the multicriteria analysis to identify the optimum operational parameters to be applied at the field level, it was observed that maximum CRE may be obtained with TiO2/Al electrode and the applied current of 1 Amps with a flow rate of 100 mL.min-1. It can be concluded that electrocoagulation is a highly efficient and the fastest method to treat dye effluents from industries.

Corncob waste derived carbon with sulfonic acid group: An efficient heterogeneous catalyst for production of ethyl levulinate as biodiesel additives

Alkyl levulinate is a biomass-based chemical compound used as a fuel additive. This research aims to produce ethyl levulinate from levulinic acid and ethanol using esterification with the assistance of a heterogeneous sulfonated carbon catalyst. The carbon sulfonate catalyst is obtained from corncob waste that has undergone carbonization at 300 °C and sulfonation using sulfuric acid at a temperature of 150 °C for 8 h. The catalyst is used for esterification with predetermined operating variables using Box-Behnken Design (BBD) on the response surface methodology (RSM). The result shows significant variables for ethyl levulinate esterification are catalyst loading and esterification time. The FTIR analysis indicates the presence of S=O bonds in the sulfonated carbon catalyst. The XRD and SEM analysis shows that the sulfonated carbon catalyst is in amorphous and mesoporous form. Catalyst reusability demonstrates that the corncob-derived carbon sulfonate catalyst can be used up to 3 times. The optimum condition for esterification is 9 h of reaction, 10 % catalyst loading, and a molar ratio of levulinic acid to ethanol of 1:10, which has 83.15 % conversion. These results present the optimum parameter conditions for an efficient heterogeneous catalyst from corncob for producing ethyl levulinate.

Improvement of horizontal streak on disparity map thru parameter optimization for stereo vision algorithm

In this paper, an improved local based stereo vision disparity map (SVDM) algorithm is proposed. The proposed local based SVDM algorithm include four stages and they are matching cost computation, cost aggregation disparity optimization and disparity refinement. The matching cost computation started by combining pixel to pixel matching techniques, which are absolute difference (AD) and gradient matching (GM) in producing the initial disparity map. Next, the cost aggregation uses minimum spanning tree (MST) segmentation, which equipped with edge preserving properties and noise filtering. Then, disparity optimization uses local approach with winner-take-all (WTA) technique. At the final stage, disparity refinement uses bilateral filter (BF) with weighted median (WM), which can improve the disparity map through noise removing and edges preserving. Then, the research continues to optimize the proposed local based SVDM algorithm through parameters optimization in obtaining the final disparity map. Here, multiple parameters from the proposed SVDM algorithm are manipulated and they are constant values for GM and several constant parameters in BF. By selecting the optimum parameter values, the performance of the proposed SVDM algorithm increased, especially robustness towards the horizontal streaks.

Emerging eco-friendly fiber-reinforced concrete with shaped synthetic aggregates using Taguchi grey relational analysis and utility concept

The present study assessed the applicability of employing Taguchi-based Grey relational analysis (T-GRA) and the Taguchi approach combined with the utility concept (T-UC) for enhancing the mix design parameters of fiber-reinforced synthetic aggregate concrete (FRSAC). Cement was supplemented with binders such as ground granulated blast furnace slag (GGBFS), metakaolin (MK), and lime powder (LP). The optimized mix proportion of FRSAC was determined to enhance the fresh and mechanical performance. Furthermore, this investigation used two weighting approaches: equally weighted and maximum deviation methods. An established L16 (45) Taguchi orthogonal array was used with five different factors, namely, cement replacement (40 %, 50 %, 60 % and 70 %), binder content (B1, B2, B3, B4), water-to-cement ratio (0.31, 0.32, 0.33, 0.34), fiber dosage (0.1 %, 0.2 %, 0.3 % and 0.4 %), and synthetic aggregate replacement (25 %, 50 %, 75 %, and 100 %) were employed to design the experiments. Then, T-GRA and T-UC were used to determine the optimum mix proportions for five response parameters: workability, compressive strength, split tensile strength, elastic modulus, and impact ductility index. Results indicated that the two methods, GRA and UC, can be successfully integrated with the Taguchi method to derive the optimized FRSAC mixture. Confirmation experiments were performed after determining the optimum mix design parameters, including cement replacement of 60 %, binder content of B4, the water-to-cement ratio of 0.34, fiber dosage of 0.1 %, and synthetic aggregate replacement of 75 %. The optimum FRSAC mix was examined for its fresh (workability) and hardened (compressive strength, split tensile strength, elastic modulus, impact ductility index) properties.

Identification of patterns of the stress-strain state of a standard plastic tank for liquid mineral fertilizers

In this study, using the method of probabilistic deterministic planning (PDP), the optimum design parameters of a standard polyethylene tank used worldwide for transporting liquid mineral fertilizers (LMF) were determined. By the finite element method, the effect of the density of liquid mineral fertilizer, tank wall thickness and four motion modes (braking, acceleration, jump and landing) on the strength of standard polyethylene tanks was studied. According to the results of the study, the five most informative areas in the tank design were identified, for which the values of maximum stresses (σmax) were obtained: filler neck, pockets, walls, tap-in points and wall transition to the tank roof. As the LMF density increases, σmax in the tank increases linearly. Increasing the tank wall thickness by 1.5 times reduces the maximum stresses by 30 to 50 %. It was found that motion mode has a significant effect on the stress-strain state of a standard tank. The “heaviest” mode for a standard tank is “braking”. The “acceleration” motion mode causes σmax of no more than 60 % of the “braking” mode values. The “lightest” mode is “landing”, in which σmax is no more than 28 % relative to “braking”. Based on the PDP method, equations were derived for calculating maximum stresses depending on LMF density, wall thickness and motion mode of the tank. Nomograms were built that make it possible to quickly determine the wall thickness of a standard tank without calculations, depending on external factors. The results of the study can be used in practice when designing safe and durable tanks for transporting liquid mineral fertilizers.

The effects of raw materials particle sizes on the solid-state reaction progress, morphology and magnetic properties of M-type strontium hexaferrites

In this work, the effects of SrCO3 and Fe2O3 particle size on the reaction process, morphology and magnetic properties of M-type strontium hexaferrites (SrM) have been further studied. Pure strontium hexaferrite magnetic sample based on SrCO3 and Fe2O3 molar ratio of 1:6 has been successfully prepared at 1150 °C. The results indicated that Fe2O3 particle size was the main factor of affecting the formation of SrM, a pure SrM phase magnetic sample was able to obtain at lower calcination temperatures by using fine Fe2O3 powder as raw material, and at the same calcination temperature, a sample using fine Fe2O3 powder as raw material was able to obtain pure SrM phase magnetic sample with shorter holding time. When the mean particle size of Fe2O3 was below 60 nm, a pure SrM phase magnetic sample was able to form at 1150 °C at a molar ratio of 1:6 of SrCO3 and Fe2O3. In this case, the magnetic parameters of the sample with the optimum magnetic parameters were saturation magnetization MS = 77.8 emu/g and coercive force HC = 4122 Oe. And the solid-state reaction process of the corresponding samples was slightly faster when the mean particle size ratio of Fe2O3 and SrCO3 was between 0.35 and 0.36. Assuming that a SrCO3 particle is surrounded by Fe2O3 particles, it can be inferred that the corresponding molar ratio of Fe and Sr of the nearest raw material particles is between 3.6 and 3.8.

Synthesis, structural characterization and in vitro digestion stability of a soluble soybean polysaccharide‑zinc chelate

The chelation reaction of soluble soybean polysaccharide (SSPS) with zinc was investigated. Using response surface methodology, the optimum parameters for SSPS-Zn synthesis were obtained: pH 5.3, SSPS-ZnCl2 mass ratio of 9.44:1, reaction temperature 50.44 °C, and reaction time 1.5 h, with the highest zinc content of 24.73 %. Compared with SSPS, SSPS-Zn increased in rhamnogalacturonan content and decreased in that of neutral monosaccharides (Fuc, Ara, Gal, Glu and Xyl). UV–vis spectra indicated that SSPS-Zn was lower than SSPS in protein content. FTIR spectra indicated that CO group of SSPS was bonded to Zn2+. X-ray diffraction spectra demonstrated that SSPS-Zn had higher crystallinity. Congo red reactions showed that SSPS possessed a triple-helix conformation while SSPS-Zn formed an irregular free-coiled conformation. EDX confirmed SSPS-Zn synthesis successfully. TGA curves exhibited that SSPS-Zn required higher temperature to undergo degradation. AFM revealed that SSPS-Zn was clustered while SSPS was filamentous. SEM micrographs showed the cracked fragments on the surface of SSPS-Zn. By in vitro simulation of gastrointestinal digestion, Zn2+ release reached 68.87 % after 2 h digestion. Consequently, the chelation of SSPS with zinc could change structure and provide a basis for research and application of novel zinc supplements.