Effects Of Different Processing Conditions Research Articles

(Invited) Scaling CO2 to MeOH Conversion in an Electrolyzer

Methanol is a desirable, value-added product from CO2 electroreduction, but is difficult to obtain in high Faradaic efficiencies. Promising results have emerged from a catalyst system comprised of cobalt pthalocyanine adsorbed onto carbon nanotubes (CoPc/CNT) in batch cell reactors, reaching Faradaic efficiencies of 40-50%.(1) In this talk, we will present our work on scaling this reaction in a 25 cm2 flow reactor with a gas diffusion electrode. We discuss the differences in the two geometries (electrolyzer vs. batch reactor) and the effect of different process conditions, such as pH, electrolyte identity and CO2 partial pressure on product selectivities. Y. Wu, Z. Jiang, X. Lu, Y. Liang, H. Wang, Nature. 575, 639–642 (2019).

Optimization of malted cowpea compositions and extrusion parameters for best quality Ethiopian emmer wheat-based snack food

Childhood malnutrition is a major concern in developing countries, particularly in Ethiopia. This study aims to address this problem by assessing the nutritional properties of snacks made from locally available raw materials. The study used a twin-screw extruder machine to study the effects of different processing conditions (barrel temperatures, feed moisture content, and cowpea/emmer wheat blending ratio) on the nutritional properties of extruded products. The results showed a highly significant effect of these processing variables on the nutritional properties of snacks. Increasing cowpea in the blend boosted the protein and fiber content of the snack products. Increasing the barrel temperature from 80 to 120 °C notably decreased the protein and fat levels in the snack. The optimization of the combined interactive effects on an extruded snack made from 19.83% cowpea and 80.17% emmer wheat, cooked at 120 °C barrel temperature with 22.04% feed moisture content, produced acceptable extruded snack items. The products developed with optimized parameters contained 16.68%, 1.55%, 2.50%, 70.95%, and 364.43 kcal/g for protein, fat, fiber, carbohydrate, and gross energy, respectively. The study concludes that blending Emmer wheat and cowpea in extruded snacks can provide high protein and gross energy. This suggests a locally viable solution for addressing protein-energy malnutrition in developing regions, particularly Ethiopia.

Effects of different curing concentrations and drying times on the microbial community structure and metabolites of dried Spanish mackerel

Cured Spanish mackerel has a promising market owing to its nutritious nature as well as ease of transportation and preservation. However, the nutritional and flavor formation mechanism of Spanish mackerel after curing and drying is unclear. To overcome this problem, the effects of different processing conditions on the free amino acid, microbial community, and flavor of Spanish mackerel were explored. Staphylococcus and Cobetia are the main microorganisms in cured mackerel and are closely associated with the formation of their quality. Compared with fresh mackerel, cured mackerel contains increased levels of protein, fat, and chloride, contributing to its distinctive flavor. The contents of free amino acids in the BA64 group were substantially higher than those in other groups, particularly the contents of threonine, glycine, and tyrosine. These findings will contribute to the development of high-quality cured Spanish mackerel products and cured aquatic products.

Bone Char Adsorption of COD and Colour from Tannery Wastewater: Breakthrough Curve Analysis and Fixed Bed Dynamic Modelling

This study delves into the simultaneous adsorption of chemical oxygen demand (COD) and colour from tannery wastewater using bone char through a fixed bed column. The bone char, which was derived from cattle skulls, was characterised using the Fourier transform infrared spectroscopy, Braeuer–Emmett–Teller surface area analysis, and the scanning electron microscope/energy-dispersive X-ray spectroscopy. The effects of different process conditions, specifically, packed bed height (5, 10, and 15 cm) and flow rate (2, 5, and 8 mL/min), on the adsorption efficiency of the fixed bed column were assessed through breakthrough curve analysis. The results revealed that the efficiency of the column bed enhanced with increasing bed height and declined with increasing wastewater flow rate. The optimal operating conditions for COD and colour removal onto the bone char occurred at 15 cm bed height and 2 mL/min flow rate. The adsorption capacities at these conditions were 227.4 mg/g and 53.03 Pt-Co/g for COD and colour, respectively. The kinetics associated with the fixed bed adsorption of COD and colour onto bone char were elucidated through the fitting of the Thomas, Adams–Bohart, and Yoon–Nelson models to the experimental data. Among the three models, the Yoon–Nelson model gave the best prediction of the experimental data. Maximum adsorption efficiencies of 80.65% and 84% were attained for COD and colour removal, respectively, proving that bone char is a promising and ecologically friendly alternative adsorbent for the treatment of tannery wastewater.

Biopolymer-loaded plasma-mediated multi-functional finishes of polypropylene fabrics

Polypropylene (PP) has unique competitiveness with other synthetic fibers due to its suitable spinnability, availability of raw materials, and low processing cost. PP fabric exhibits excellent chemical, physical, and mechanical properties, such as a light texture, adequate tensile strength, and resistance to most chemicals. However, the absence of reactive functional groups in PP fiber, besides its high crystallinity, results in hydrophobic surface, low affinity to dyestuffs, and poor antistatic properties, which restrict its use in the clothing field. Herein, a water- and energy-saving, eco-friendly finish is proposed to render PP desired properties suitable for textile applications. The surface of PP fabric was activated using oxygen and nitrogen plasma radiations. The plasma-irradiated PP fabric was post-treated with two renewable eco-friendly proteinic biopolymers, namely gelatin and sericin, in the presence and absence of a crosslinking agent. The effects of different process conditions on the properties of the modified PP, including the duration of plasma exposure, the concentration of biopolymer, and treatment temperature were monitored. The affinity of the treated PP fabric towards anionic and cationic dyes was evaluated. The findings of this study demonstrated that the comfort attributes of the plasma/biopolymer-finished fabrics, such as the induced antistatic properties, wettability, and ultraviolet protection, were remarkably improved. The plasma-mediated biopolymer-finished PP fabrics were found dyeable with cationic and anionic dyes. The change in the chemical and morphological structures of PP fabrics was monitored using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy.

Selectivity and competitive mechanism of cation exchange resin for Fe, Mg, and Al ions in phosphoric acid

AbstractThe presence of iron, magnesium, and aluminum elements as the primary impurities in wet‐process phosphoric acid (WPA) adversely affects the industrial phosphoric acid and subsequent phosphorus chemical products. This study aims to investigate the selectivity and competition mechanism of Sinco‐430 cation exchange resin for Fe, Mg, and Al ions in phosphoric acid solution. By studying the effects of different process conditions on the removal efficiency, the suitable conditions for the static removal of metal ions from Fe‐Mg, Al‐Mg, and Fe‐Al binary systems were determined: solid–liquid mass ratio (S/L) of 0.3, phosphoric acid concentration of 27.61 wt.%, system temperature of 50°C, and rotational speeds of 200, 400, and 200 rpm, respectively. By calculating the selectivity coefficients of the resin for metal ions under different experimental conditions and mutual replacement experiments, the semi‐empirical formulas for the selectivity coefficients were derived and order of selectivity was determined as follows: Mg2+ > Fe2+ > Al3+. Visual MINTEQ 3.1 software and density functional theory (DFT) calculations demonstrated that at low pH, the main forms of Fe, Mg, and Al present in phosphoric acid were FeH2PO4+, Mg2+, and AlH2PO42+, respectively. This finding explained the differences in selectivity of the resin for Fe, Mg, and Al. The dynamic removal of metal ions from phosphoric acid was investigated. The order of metal ion selectivity of the resin by the dynamic method is the same as that of the static method, and the dynamic exchange behaviour was most consistent with the Yan model.

Effects of different processing conditions on the carotenoid's composition, phenolic contents, and antioxidant activities of Brassica campestris leaves

Leafy vegetables are enriched with health-promoting compounds such as carotenoids and polyphenols. Different processing treatments have been shown to affect the amounts of these compounds. In this study, mustard (Brassica campestris) leaves were subjected to various processing treatments, boiling, frying, freezing, sonication, microwaving, and blanching. Carotenoid contents were determined using HPLC-DAD while the total phenolic, flavonoids, anthocyanin, and antioxidant activities were determined using established spectroscopic protocols. It has been found that different processing treatments concentrated the lutein, flavoxanthin, and β-carotene contents of mustard leaves, while frying has been found to have deleterious effects on these compounds. During boiling the concentration of violaxanthin, antheraxanthin, flavoxanthin, and lutein was significantly increased to 87.4, 29.9, 20.4, and 340.8 μg/g respectively versus control. The total anthocyanin and phenolic contents of mustard leaves were better preserved during frying having values of 6.2 mg/L and 1281.2 mg/100g, respectively, whereas the total flavonoid contents (TFC) in the control sample was 111.8 mg/100g. Among the studied treatments the highest TFC was reported in the blanched samples (108.7 mg/100g), followed by sonication (107.1 mg/100g). During microwave and sonication, the antioxidant potential of the treated samples had significantly increased while in other treatments, it was reduced.

Effect of different process conditions on the physicochemical and antimicrobial properties of plasma-activated water

The physicochemical properties of plasma-activated water (PAW) generated under different process conditions were investigated, and their changes under different storage conditions were also studied. The results showed that increasing the processing time and power, and decreasing generated water volume, could cause an increase in the redox potential, conductivity, and temperature of PAW, and a decrease in its pH. A slower dissipation of the reactive oxygen and nitrogen species in PAW was found on storage at 4 °C in a sealed conical flask than on storage at room temperature. The inactivation ability of plasma-activated lactic acid (LA) to Listeria monocytogenes (L. monocytogenes) and Pseudomonas aeruginosa (P. aeruginosa) was higher than that of PAW or LA alone under the same experimental conditions. The results of this study may provide theoretical information for the application of PAW as a potential antimicrobial agent in the future.

Drug-excipient compatibility studies in formulation development: A case study with benznidazole and monoglycerides

Monoglycerides (MGs) such as glycerol monolaurate (GML) and glycerol monostearate (GMS) have been used as excipients in oral formulations because of their emulsifying effect as well as their ability to inhibit the precipitation and intestinal efflux of drugs. Excipient-drug compatibility studies, however, have been underexplored. In this study, benznidazole (BNZ) was selected as a drug model due to the difficulty in improving its solubility and because of the potential impact on public health (it is the only drug currently used to treat Chagas disease). The effect of different processing conditions (maceration, ball milling, and melting) on the physical-chemistry properties of BNZ/MGs mixtures was investigated to guide the rational development of new solid formulations. GML was more effective in improving the solubility of BNZ, which could be due to its more malleable structure, less hydrophobic nature, and greater interaction with BNZ. The formation of hydrogen bonds between the imidazole group of BNZ and the polar region of GML was confirmed by spectroscopy analyses (IR, 1H NMR). The higher the monoglyceride content in the mixture, the higher the BNZ solubility. Regardless of the method of processing the mixture, the drug was found to be crystalline. Polarized light microscopy analysis showed the presence of spherulites. Overall, these findings suggest that preparation methods of BNZ:MGs formulations that involve thermal or/and mechanical treatment have a low impact on the solid properties of the material, and this allows for the production of formulations with reproducible performance.

Effect of vacuum freeze drying and hot air drying on dried mulberry fruit quality.

Two different drying methods (vacuum freeze-drying and hot-air drying) were used to dry mulberry of three varieties 'Baiyuwang'(D1), 'Longsang'(D2) and 'Zhongshen.1'(D3), and the fresh fruit of each variety was used as the control. The effects of different processing conditions on the physical characteristics, nutrients, functional components and antioxidant activity of mulberry fruit were analyzed. The results show that after different drying methods, after vacuum freeze-drying, the physical properties of dried mulberry fruit such as wettability, hygroscopic property and water retention, soluble protein, ascorbic acid and other nutrients, functional components such as polyphenols, resveratrol, chlorogenic acid and anthocyanin, and antioxidant activities such as DPPH free radical scavenging ability and ABTS free radical scavenging ability were superior to hot air drying (P < 0.01). It was concluded that vacuum freeze drying was more beneficial for retaining the original quality of mulberry than hot air drying. This study can provide a retaining theoretical basis for mulberry deep processing and comprehensive development and utilization.

High-performance expanded graphite from flake graphite by microwave-assisted chemical intercalation process

Herein, a facile preparation method with characteristics of energy-saving, efficient and environmentally friendly is proposed. Firstly, GICs (Graphite Intercalation Compounds) were synthesized by microwave assisted hydrothermal method using flake graphite (FG) as raw material, H2SO4, and K2S2O8 as oxidative intercalations by microwave-assisted oxidation for 5 min, and then EG was prepared from obtained GICs by microwave irradiation for 40 s under the microwave power of 800 W, and the effect of different process conditions on EG expansion volume (EV) was studied. The results show that EG with a good expansion can be rapidly prepared by microwave irradiation, and the EV value can reach 455 mL /g under the optimal conditions. In particular, the prepared EG has a high graphitization degree with less structural damage, exihibiting good industrial application prospects. The mechanism of K2S2O8 oxidation and graphite expansion under microwave irradiation was analyzed. In adition, flexible graphite foil papers prepared with the obtained EG exhibit good electrical conductivity and thermal properties. The as prepared EG material shows an efficient adsorption of hydraulic oil and vegetable oil and excellent flame retardant performance. This preparation method is green, low cost, and safe, and can be used for the efficient batch preparation of EG.

A Simple Method to Convert Cellular Polymers into Auxetic Metamaterials

The objective of this study was to present a simple and environmentally friendly process combining low pressure (vacuum) and mechanical compression to convert low-density polyethylene (LDPE) foams into low-density foams (76–125 kg/m3) with negative tensile and compressive Poisson’s ratios (NPR). As a first step, four series of recycled LDPE foams (electronics packaging) with starting densities of 16, 21, 30 and 36 kg/m3 were used to determine the effect of different processing conditions including temperature and pressure. Based on the optimized conditions, the tensile and compressive Poisson ratios of the resulting auxetic foams reached −2.89 and −0.66, while the tensile and compressive modulus of the auxetic foams reached 40 kPa and 2.55 kPa, respectively. The foam structure of the samples was characterized via morphological analysis and was related to the mechanical properties before and after the treatment (i.e., foams with positive and negative Poisson’s ratios). The tensile and compressive properties (Young’s modulus, strain energy, energy dissipation and damping capacity) for these auxetic foams were also discussed and were shown to be highly improved. These auxetic foams can be applied in sports and military protective equipment. To the best of our knowledge, there is only one report on vacuum being used for the production of auxetic foams.

Design and Optimization of Thermal Field for PVT Method 8-Inch SiC Crystal Growth.

As a wide bandgap semiconductor material, silicon carbide has promising prospects for application. However, its commercial production size is currently 6 inches, and the difficulty in preparing larger single crystals increases exponentially with size increasing. Large-size single crystal growth is faced with the enormous problem of radial growth conditions deteriorating. Based on simulation tools, the physical field of 8-inch crystal growth is modeled and studied. By introducing the design of the seed cavity, the radial temperature difference in the seed crystal surface is reduced by 88% from 93 K of a basic scheme to 11 K, and the thermal field conditions with uniform radial temperature and moderate temperature gradient are obtained. Meanwhile, the effects of different processing conditions and relative positions of key structures on the surface temperature and axial temperature gradients of the seed crystals are analyzed in terms of new thermal field design, including induction power, frequency, diameter and height of coils, the distance between raw materials and the seed crystal. Meanwhiles, better process conditions and relative positions under experimental conditions are obtained. Based on the optimized conditions, the thermal field verification under seedless conditions is carried out, discovering that the single crystal deposition rate is 90% of that of polycrystalline deposition under the experimental conditions. Meanwhile, an 8-inch polycrystalline with 9.6 mm uniform deposition was successfully obtained after 120 h crystal growth, whose convexity is reduced from 13 mm to 6.4 mm compared with the original scheme. The results indicate that the optimized conditions can be used for single-crystal growth.

Process study of CeO2 preparation by jet-flow pyrolysis via microwave heating

The spray pyrolysis method has the disadvantage of nozzle plugging, and the conventional heating model causes a large temperature gradient, which leads to unevenly heated reactants. This study used cerium chloride heptahydrate and Venturi reactor as raw material and core equipment. The technology of microwave heating was combined to prepare single-phase sphere-like cerium oxide. The mean size of the particles was near 80nm. The product was characterized via XRD, SEM, and EDS technologies. The purity, morphology, and energy consumption were compared with the conventional spray pyrolysis. Fluent software coupled with HFSS was employed to simulate the effects of different process conditions on products? purity and temperature field in the reactor. There was good correspondence between experimental and simulated results. The results showed that as gas velocity Vg increased, the tendency of the temperature field distribution did not change. The lowest mass fraction of chlorine element reached 0.13% when the gas inlet velocity reached 1.7 m/s. When the material inlet velocity was 0.05 m/s, the mass fraction of the chlorine element was below 0.1%, which indicated that the reactants had a complete reaction. It has been calculated that the heating cost, energy consumption, and CO2 emission decreased sharply compared with the spray pyrolysis method.

Effect of different processing conditions to obtain expanded extruded based on cowpea

Abstract Cowpea is grown mainly in regions with a hot semi-arid climate, where other pulses do not develop satisfactorily. It is the 4th most produced pulse in the world, thus supplying the domestic and export markets. Following the trends of the food products market, a study was carried out to identify the best condition of the extrusion process, to transform these nutritious grains into quality expanded products and ready for consumption. The grains were decorticated and transformed into cotyledon flour. This flour was conditioned and the Evolum HT25 twin screw extruder feeder was adjusted to a rate of 7 kg h-1. A Box-Behnken 23 design was used, considering the following variables and levels: extrusion temperature from 100 °C to 140 °C (in the 7th to 10th zone), screw speed (300 to 700 rpm) and conditioning moisture from 12% to 16%. The temperature affected linearly and negatively (p ≤ 0.05) the sectional expansion index (2.65 to 7.64). The screw speed interfered linearly and positively (p ≤ 0.05) in the longitudinal (1.12 to 9.32) and volumetric (4.91 to 24.15) expansion index, and negatively with the water absorption index (3.05 to 3.86 g g-1). The screw speed (positive linear and negative quadratic), the moisture content (negative quadratic) and the interaction (positive) between the two interfered (p ≤ 0.05) in the water solubility index (25.89% to 33.85%). The hardness value (1.24 to 2.83 N) was affected (p ≤ 0.05) by screw speed (negative linear and positive quadratic), temperature (negative quadratic), moisture (positive quadratic), and interactions of moisture with temperature and screw speed. To obtain a hardness value close to that of commercial extrudates and high-water solubility, the maximum global desirability obtained was 0.81 for extrusion at 135.6 °C, 700 rpm and 12% moisture.

Study on Preparation of Nano-ZnO by Zinc Hypoxide in Rotary Hearth Furnace

To realize the high value-added utilization of zinc hypoxide in a rotary hearth furnace, nano-ZnO was prepared by H2SO4 wet leaching combined with the Na2CO3 precipitation process. The effects of different process conditions on the leaching rate of Zn were analyzed, and the feasibility of preparing nano-ZnO from zinc hypoxide was discussed. The results showed that the optimal process conditions for H2SO4 leaching of zinc hypoxide in a rotary hearth furnace were as follows: H2SO4 concentration 2.0 mol·L−1, leaching temperature 60 °C, leaching time 90 min, and liquid-solid ratio 8:1. Under these conditions, the leaching rate of Zn reached 95%. The calculation results of leaching kinetics showed that the restrictive link of the H2SO4 leaching process was a chemical reaction process; the apparent activation energy was 14.45 kJ·mol−1; and the reaction order was 0.6. The precursor obtained by Na2CO3 precipitation treatment was Zn5(OH)6(CO3)2. After calcination at 400 °C, the nano-ZnO with a diameter of less than 100 nm and length greater than 1 μm was obtained. H2SO4 leaching combined with the Na2CO3 precipitation process provided a new approach for high value-added utilization of zinc hypoxide in a rotary hearth furnace.

Impact energy absorption and fracture mechanism of FFF made fiberglass reinforced polymer composites

PurposeThe fiber reinforced polymer composites are becoming more critical because of their exceptional mechanical properties and lightweight structures. Fused filament fabrication (FFF) is a three-dimensional (3D) printing technique that can manufacture composite structures. However, the effect of impact performance on the structural integrity of FFF made composites compared to the pre-preg composites is a primary concern for the practical usage of 3D printed parts. Therefore, this paper aims to investigate the effect of different processing parameters on the impact performance of 3D printed composites.Design/methodology/approachThis paper investigates the impact of build orientation, fiber stacking sequence and fiber angle on the impact properties. Two build orientations, three fiber stacking sequences and two different fiber angles have been selected for this study. Charpy impact testing is carried out to investigate the impact energy absorption of the parts. Onyx as a matrix material and two different types of fibers, that is, fiberglass and high strength high temperature (HSHT) fiberglass as reinforcements, are used for the fabrication.FindingsResults indicate that build orientation and fiber angle largely affect the impact performance of composite parts. The composite part built with XYZ orientation, 0º/90º fiber angle and B type fiber stacking sequence resulted into maximum impact energy. However, comparing both types of fiber reinforcement, HSHT fiberglass resulted in higher impact energy than regular fiberglass.Originality/valueThis study evaluates the damage modes during the impact testing of the 3D printed composite parts. The impact energy absorbed by the composite samples during the impact testing is measured to compare the effect of different processing conditions. The investigation of different types of fiberglass reinforced with Onyx material is very limited for the FFF-based process. The results also provide a database to select the different parameters to obtain the required impact properties.

Sugar molasses as a sustainable precursor for the synthesis of graphene sand composite adsorbent for tetracycline and methylene blue removal.

Sugar molasses from agricultural waste could be a sustainable carbon source for the synthesis of graphene adsorbent introduced in this work. The sugar molasses was successfully converted to graphene-like material and subsequently coated on the sand as graphene sand composite (GSC), as proven by XRD, XPS, Raman spectroscopy, and SEM with EDX mapping analyses. The adsorption performance of GSC was evaluated against the removal of Tetracycline (TC) and methylene blue (MB) pollutants from an aqueous solution in a fixed bed column continuous-flow adsorption setup. The effect of different process conditions: bed height (4-12cm), influent flow rate (3-7mL/min), and contaminants' concentration (50-150ppm) was investigated. The results revealed that column performance was improved by increasing the bed depth and lowering the flow rate and concentration of the pollutants. The best removal efficiency was obtained when the bed height was 12cm, the influent flow rate of 3mL/min, and the pollutants' initial concentration was 50mg/L. Thomas, Adams-Bohart, and Yoon-Nelson models were attempted to fit the breakthrough curves. Regeneration of the GSC indicated the decline of breakthrough time from 240-280 to 180min, reflecting the decrease in adsorptive sites due to the incomplete regeneration process. Overall, sugar molasses was shown to be a low-cost precursor for synthesizing valuable graphene material in the form of GSC, which can reduce the problem for industrial waste management of sugar molasses, and the GSC could be used as an adsorbent for environmental application.

Evaluation of the Preservation and Digestion of Seal Meat Processed with Heating and Antioxidant Seal Meat Hydrolysates.

Seal meat is of high nutritive value but is not highly exploited for human food due to ethical issues, undesirable flavors, and loss of nutrients during the processing/cooking step. In this work, commercially available processed seal meat was treated with its hydrolysates as preservatives with the aim of improving nutrient bioavailability. The contents of the nutrients were analyzed after digestion using a simulated dynamic digestion model, and the effects of different processing conditions, i.e., low-temperature processing and storage (25 °C) and high-temperature cooking (100 °C), of seal meat were investigated. Hydrolysates with antioxidant activity decreased the amounts of the less desirable Fe3+ ions in the seal meat digests. After treatment with hydrolysates at room temperature, a much higher total Fe content of 781.99 mg/kg was observed compared to other treatment conditions. The release of amino acids increased with temperature and was 520.54 mg/g for the hydrolysate-treated sample versus 413.12 mg/g for the control seal meat sample treated in buffer. Overall, this study provides useful data on the potential use of seal meat as a food product with high nutritive value and seal meat hydrolysates with antioxidant activity as preservatives to control oxidation in food.

Numerical simulation of the top side-pouring twin-roll casting of 6.5 wt.% Si steel process

Using the finite element software ProCAST to predict the temperature field, the flow field, the turbulent kinetic energy, and melt-pool outlet temperature of the top side-pouring twin-roll casting (TSTRC) of 6.5 wt.% Si steel process. The effect of different process conditions on the TSTRC process was investigated through numerical simulation, and a processing technic appropriate for the production of 6.5 wt.% Si steel was obtained. Meanwhile, the influence of violent stirring in the melt-pool on the microstructure under different process conditions was evaluated. The results showed that vigorous stirring in the melt-pool was conducive to formate the equiaxed crystal structure. We realized the near-final shape of the metal sheet and achieved the near-final shape of the microstructure. An appropriate process was selected to show good consistency with the experimental results.