Addition Of Iron Oxide Research Articles

Lalombi Tropical Peat Soil Improvement Using Iron Oxide admixture and Cement

Peat soil has a relatively high water content of up to 400%. With a high moisture content, peat soil can hinder construction work. For this reason, in construction planning, an investigation must be carried out on the characteristics and strength of the soil, especially the properties of the soil that affect the bearing capacity of the soil to withstand the load of the construction on it. This study aimed to determine the characteristics and changes in the bearing capacity of peat soil after mixing with cement and iron oxide admixture. The variation of mixing iron oxide is 0%, 4%, 8%, and 16%, while for variation of cement mixture is 5%. This research was conducted on the soil, including testing physical and mechanical properties. Engineering properties tests include direct shear and consolidation tests. This research conducted the elemental chemical content in peat soil and SEM (Scanning Electron Microscope) test. Based on the classification of peat soil at this location with an ash content-value of 29.41%, it can be classified as High Ash Peat (peat with ash content > 25%). In the direct shear test, the cohesion value and the shear angle continued to increase as the percentage of the iron oxide mixture increased to 16%, where the shear angle changed from 7.60º to 45°. In the consolidation test, the original soil Cc value of 0.00820 decreased with the addition of iron oxide to 16%; the Cc value decreased to 0.00277. The decrease in Cc indicates that the soil becomes easily compacted, and The value of the Coefficient of Consolidation (Cv) on peat soil was 0.00535 cm²/sec. The most significant increase in the original soil with a mixture of 16% iron oxide was 0.01463 cm²/sec. The Chemical results have been given a mixture of 16% iron oxide and 5% cement, the change of C (Carbon), Fe (Ferrum) and Ca (Calcium). The value of O (Oxygen) in peat soil was 48.05% and then decreased to 43.67%, this indicates that the pores in the peat soil are reduced, and when the pores are reduced, the peat soil becomes denser. The value of Si (Silica) also decreased from 30.01% to 21.21%. This occurred because silica reacted with lime. After all, silica is an adhesive that binds lime, making the granules denser. Peat soil’s Fe (Ferrum) value was 3.12%, then increased to 16.72%. This also helped the soil to become stronger because of the higher specific gravity of iron. Peat soil’s Al (aluminium) value was 12.15% after being given a mixture of iron oxide and cement increased to 12.16%.

Iron oxides impact sulfate-driven anaerobic oxidation of methane in diffusion-dominated marine sediments

Microbial iron (Fe) reduction by naturally abundant iron minerals has been observed in many anoxic aquatic sediments in the sulfidic and methanic zones, deeper than it is expected based on its energetic yield. However, the potential consequence of this “deep” iron reduction on microbial elemental cycles is still unclear in sediments where diffusion is the dominant transport process. In this contribution, we experimentally quantify the impact of iron oxides on sulfate-driven anaerobic oxidation of methane (S-AOM) within the sulfate methane transition zone (SMTZ) of marine diffusive controlled sediments. Sediments were collected from the oligotrophic Southeastern (SE) Mediterranean continental shelf and were incubated with 13C-labeled methane. We followed the conversion of 13C-labeled methane as a proxy of S-AOM and monitored the sediment response to hematite addition. Our study shows microbial hematite reduction as a significant process in the SMTZ, which appears to be co-occurring with S-AOM. Based on combined evidence from sulfur and carbon isotopes and functional gene analysis, the reduction of hematite seems to slow down S-AOM. This contrasts with methane seep environments, where iron oxides appear to stimulate S-AOM and hence attenuate the release of the greenhouse gas methane from the sediments. In the deep methanic zone, the addition of iron oxides inhibits the methanogenesis process and hence methane gas production. The inhibition effect deeper in the sediment is not related to Fe-AOM as a competing process on the methane substrate, since Fe-AOM was not observed throughout the methanic sediments with several iron oxides additions.

The Effect of Thermoradiation Treatment on the Structure of Potassium Aluminoborate Glasses with Iron Oxide Additives

The Effect of Thermoradiation Treatment on the Structure of Potassium Aluminoborate Glasses with Iron Oxide Additives

Influences of Iron Oxide Nanomaterial and Hydrogen Addition into Sunflower Biodiesel/Diesel Powered Diesel Engine Performance and Emissions

AbstractIn this study, effects of iron oxide (Fe3O4) and hydrogen (H2) additions into 20% sunflower biodiesel + 80% diesel (B20) operated compression ignition engine performance and emissions are evaluated. Diesel fuel (D) is selected as a reference fuel for comparison purpose. Reduced performance level with B20 can be recovered with use of nanoparticle and hydrogen due to their superior combustion characteristics. In comparison to diesel, B20 mixture has caused to reduction on power by 6.44% while addition of nanoparticle and hydrogen (H_B20_Fe) have increased power by 5.76%. B20 mixture led to decrease carbon monoxide (CO) emission by 7.92% whereas nanoparticle and hydrogen addition have caused further decrement by 12.35% compared to diesel. Diesel shows best nitrogen oxides (NOx) emission characteristics of all. Increment levels are 7.24% and 12.94 for B20 and H_B20_Fe, respectively.

Sunflower waste – manganese iron oxide composite for hazardous dye removal

Sunflower waste (SF), an easily available agricultural waste was used as a primary material in the synthesis of sunflower waste – manganese iron oxide (SF-MIO) composite for the aim of waste recycling and synthesizing new composite material for dye adsorption. The synthesized adsorbent was characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA) and Brauner-Emmett-Teller (BET) analysis. Dye adsorption ability of the SF-MIO composite in the aqueous solution was investigated using the anionic dye Congo Red (CR). Effect of adsorption parameters such as adsorbent dosage, temperature, initial dye concentration and time were investigated. According to the characterization results, manganese iron oxide addition provided porous microstructure to sunflower waste and increased its surface area from 1.1814 to 47.1415 m2/g thus made sunflower waste more suitable for adsorption. Adsorption process was maintained in endothermic nature and maximum adsorption capacity of SF-MIO on to CR was calculated as 45.66 mg/g. Pseudo-first order, pseudo-second order, Elovich kinetic models and Langmuir, Freundlich, Temkin and Halsey isotherms were studied. The adsorption behavior of CR on SF-MIO composite can be well described by Freundlich and Halsey isotherm models (R2=0.996) and pseudo-second order kinetic model (R2=0.999).

Iron (oxyhydr)oxides shift the methanogenic community in deep sea methanic sediment - insights from long-term high-pressure incubations

Intermittent increases of dissolved ferrous iron concentrations have been observed in deep marine methanic sediments which is different from the traditional diagenetic electron acceptor cascade, where iron reduction precedes methanogenesis. Here we aimed to gain insight into the mechanism of iron reduction and the associated microbial processes in deep sea methanic sediment by setting up long-term high-pressure incubation experiments supplemented with ferrihydrite and methane. Continuous iron reduction was observed during the entire incubation period. Intriguingly, ferrihydrite addition shifted the archaeal community from the dominance of hydrogenotrophic methanogens (Methanogenium) to methylotrophic methanogens (Methanococcoides). The enriched samples were then amended with 13C-labeled methane and different iron (oxyhydr)oxides in batch slurries to test the mechanism of iron reduction. Intensive iron reduction was observed, the highest rates with ferrihydrite, followed by hematite and then magnetite, however, no anaerobic oxidation of methane (AOM) was observed in any treatment. Further tests on the enriched slurry showed that the addition of molybdate decreased iron reduction, suggesting a link between iron reduction with sulfur cycling. This was accompanied by the enrichment of microbes capable of dissimilatory sulfate reduction and sulfur/thiosulfate oxidation, which indicates the presence of a cryptic sulfur cycle in the incubation system with the addition of iron (oxyhydr)oxides. Our work suggests that under low sulfate conditions, the presence of iron (oxyhydr)oxides would trigger a cascade of microbial reactions, and iron reduction could link with the microbial sulfur cycle, changing the kinetics of the methanogenesis process in methanic sediment.

The Effect of Soil Amendments on Trace Elements’ Bioavailability and Toxicity to Earthworms in Contaminated Soils

The aim of this study was to assess the impact of soil amendments, characterized by different sorption properties, on the effectiveness of trace elements’ (Cu, Zn, Pb, Cd, Ni, and Cr) stabilization and bioavailability to earthworms. The study was conducted as a microcosm experiment using soil derived from a heavily contaminated post-industrial area. The Eisenia veneta earthworm was cultured for 4 weeks in soils amended with materials characterized by different properties, origins, and potential effects on limiting the availability of metals in soils: two type of compost (Zabrze compost-ZC; GWDA compost-GC), two types of biosolid (Bełchatów biosolids-BB, Grabów biosolids-GB), calcium phosphate (CP), iron oxide (IO), bentonite (BE), rock waste (RW), and limestone (CC). After the incubation, the biomass and survival numbers of the earthworm species decreased significantly (p < 0.05). The accumulation of metals in the earthworm tissues expressed by the bioaccumulation factor value (BSAF) were dependent on the type of amendment applied to the soil. The highest decrease in the earthworms’ weight and survival rate was caused by compost (72%) and bentonite (33%), while the lowest was caused by the rock waste (10%) and iron oxide (11%). The biosolids exhibited the greatest toxicity, causing the mortality of all the earthworms. The accumulation of metals in earthworm tissues and the BSAF value were dependent on the type of amendment applied to the soil. The BSAF for the contaminated soil by Cd decreased to the greatest extent after the addition of ZC (by 57%), GC (55%), CP (41%), and IO (37%). A similarly positive effect was noted for Pb after IO addition (45% decrease). The Zn, Cr, and Ni concentration in earthworms, contrary to other elements, increased, regardless of the amendment. The results showed that the applied soil amendments were characterized by varying potential for the reduction in the metal bioavailability in the soil, depending on their composition and physicochemical properties. Moreover, earthworms may exhibit a diversified response to soil amendments as a result of the impact of amendment on the metal forms in soils and their direct impact on organisms. Generally, the Cd was easily transferred from the soil into and accumulated in the earthworm tissues. Our study confirms that this element creates the highest risk for the trophic chain in soils affected by the Zn and Pb smelting industry. Moreover, greater Zn supply reduces the accumulation of Cd in animal bodies. This study provides valuable practical knowledge on the short-term biological effects of a range of soil amendments in metal-contaminated soils.

Improving the technological properties of red stoneware tiles derived from Ratchaburi red clay by the addition of iron oxide

Red clay from Ratchaburi province (Thailand), called Ratchaburi red clay (RRC), is normally used as a raw material for earthenware production in local industries. However, RRC is rarely used for producing red stoneware tiles due to firing temperature requirements. Present work aims to improve the properties of red stoneware tiles derived from RRC by the addition of iron oxide (Fe2O3). The samples composed of RRC, kaolin, and potassium feldspar with different contents of Fe2O3, were prepared by dry pressing method and fired at 1000–1200 °C. The water absorption and apparent porosity of samples decreased with increasing the content of Fe2O3 and firing temperature. Moreover, adding Fe2O3 up to a total content of 8.05 wt% not only enhanced the flexural strength and reduced the firing temperature but also reduced the water absorption to lower than 1.5% after firing at 1150 °C. Conversely, the flexural strength reduced when a total content of Fe2O3 up to 9.99 wt%. In addition, the evidence of excess Fe2O3 was observed in microstructure and XRD results.

Comparative effects of ferric hydroxide and (semi) conductive iron oxides on the anaerobic digestion of oxytetracycline-contaminated dairy manure

Additives, such as iron oxides, have been used in anaerobic digestion (AD) to promote direct interspecies electron transfer and to boost methane yield. However, the function of additives in the AD of antibiotic-contaminated organic wastes remained unclear. In this study, the effects of ferric hydroxide and (semi) conductive iron oxides, namely hematite and magnetite, on the AD of oxytetracycline (OTC)-contaminated dairy manure were investigated. Each iron oxide was assigned to a set of experiment where 0.25 g/L of OTC was added to 1 L batch digesters, while the concentration of iron oxide was varied from 0.08 to 0.34 g/L. Generally, magnetite was the most effective iron oxide to enhance methane yield in OTC-free dairy manure followed by ferric hydroxide and hematite. However, when the manure was contaminated with OTC, higher methane yield was observed in ferric hydroxide followed by hematite, while the lowest was with magnetite. In all digesters, the highest methane yield was observed with ferric hydroxide at 0.08 g/L, which was 1.43-fold of that with OTC and without iron oxides. The kinetic studies of methane yield demonstrated that the addition of iron oxides in the AD of OTC-contaminated dairy manure did not shorten the lag phase period despite the increase of methane yield. Thus, the increase of methane yield with ferric hydroxide was attributed to the possible formation of Fe-OTC complex, which attenuated the inhibition of OTC. A strategy to recover OTC residue in the AD was proposed using magnetite, a ferromagnetic particle, and high gradient magnetic separator.

Thermophysical properties of molten FeO1.5, (FeO1.5)0.86–(ZrO2)0.14 and (FeO1.5)0.86–(UO2)0.14

ABSTRACT FeO1.5 is a promising candidate for a sacrificial material to lower the liquidus temperature of molten corium while keeping the viscosity as low as possible in order to mitigate the molten core–concrete interaction. Phase diagrams of such systems as FeO1.5–ZrO2 and FeO1.5–UO2 indicate that the FeO1.5 addition would significantly lower the liquidus temperature of corium, but how it would affect the viscosity has not been investigated. Thus, the viscosity of FeO1.5, (FeO1.5)0.86–(ZrO2)0.14, and (FeO1.5)0.86–(UO2)0.14 was measured using the aerodynamic-levitation technique coupled with the droplet-oscillation method. It was found that the viscosity of (FeO1.5)0.86–(ZrO2)0.14 at approximately 2100 K is almost identical to that of ZrO2 at around 3200 K, and that (FeO1.5)0.86–(UO2)0.14 maintains a low viscosity at a temperature well below the melting temperature of UO2, owing to the low viscosity of FeO1.5. These results indicate that the iron oxide addition would not only lower the liquidus temperature of the molten corium but also keep its fluidity as high as possible.

Soil additives immobilising heavy metals in contaminated soils

Addition of iron oxides, lime, clay minerals and other substances can be used to decrease the plant availability of toxic heavy metals such as Pb, Zn, and Cd. Extractability and consequently plant concentrations may be reduced in some cases by more than 50%. The assessment of remediation processes is supported by biomonitoring methods in the field with Plantago lanceolata and in the greenhouse by barley test experiments, in combination with extraction by ammonium nitrate.

Coloring effect of iron oxide content on ceramic glazes and their comparison with the similar waste containing materials

The effects of adding iron oxide to ceramic glaze formulations were studied in this study. Iron oxide was added in different weight ratios into the reactive transparent glaze, reactive opaque glaze, and transparent glaze formulations. The iron oxide content in the glaze composition, the coloring mechanisms, the phase distributions, and surface properties at temperatures of 950–1000-1050-1200 °C in the oxidation firing medium were investigated. Scanning Electron Microscopy (SEM) to determine the microstructural and morphological characterizations of the test glazes, X-Ray Diffractometry (XRD) to determine the crystallographic properties and phases, and X-Ray Fluorescence (XRF) analyses to determine the elemental and chemical composition were performed. In addition to these, surface images were examined with Digital Microscope (DM) and Commission Internationale de l'Eclairage (CIE) L*a*b, and water absorption values were compared. In addition, taking into account environmental factors, a comparison of ceramic glazes with the same amount of waste iron oxide was also performed for same purpose. As a result of the studies, it was observed that the addition of iron oxide and/or waste iron oxide did not have a negative effect, and coloring effects on the glaze layer were observed at different rates and firing temperatures.

Photoprotection for all: Current gaps and opportunities

The effects of solar radiation on human skin differ based on the skin phototype, presence or absence of photodermatoses, biologic capacity to repair DNA damage, wavelength, intensity of sun exposure, geographic latitude, and other factors, underscoring the need for a more tailored approach to photoprotection. To date, the focus of photoprotection guidelines has been to prevent sunburn and DNA damage induced by UV radiation, both UVB and UVA; however, several recent studies have shown that visible light also generates reactive oxygen and nitrogen species that can contribute to skin damage and pigmentation on the skin, particularly in people with skin of color. Therefore, individuals with dark skin, while naturally better protected against UVB radiation by virtue of the high eumelanin content in melanocytes, may need additional protection from visible light-induced skin damage. The current options for photoprotection products need to expand, and potential strategies against visible light include the addition of iron oxide, titanium dioxide, and biologically relevant antioxidants to sunscreen formulations as well as supplementation with orally active antioxidants.

Ramie fiber reinforced composites with flame retardant structure design: flammability, smoke suppression, and mechanical properties

Abstract In this work, the structure of composite was designed as Core Stack and Surface Stack, which was treated with the expandable graphite (EG) and metal oxides such as iron oxide (IO), hydroxyapatite (HA), and aluminum tri-hydroxide (ATH). The mechanical performance of composites was characterized via flexural performance and interlaminar shear strength analysis. The flame retardance and smoke suppression of composite was explored in detail by LOI, UL-94, and cone calorimeter test. The findings presented that flexural properties of composites were observed to decrease due to delamination of surface stack, whilst no significant effect on interlaminar shear strength. In comparison with control composite, the loading of metal oxide into composite Surface Stack led to the reduction of peak heat release rate, total heat release, and fire growth index effectively. Moreover, the remarkable decrease in total smoke production could be observed due to the addition of iron oxide and the flame retardant mechanism was discussed. This study was the preliminary exploration of composite with flame retardant design which could be potential solution to improve flame retardancy and smoke suppression of composite with better mechanical structure preservation.

Impact of Metallic Nanoparticles on In Vitro Culture, Phenolic Profile and Biological Activity of Two Mediterranean Lamiaceae Species: Lavandula viridis L'Hér and Thymus lotocephalus G. López and R. Morales.

Nanoparticles (NPs) recently emerged as new chemical elicitors acting as signaling agents affecting several processes in plant metabolism. The aim of this work was to investigate the impact of the addition of copper oxide (CuO), zinc oxide (ZnO) and iron oxide (Fe3O4) NPs (<100 nm) at different concentrations (1, 5 and 10 mg/L) to the culture media on several morphological, physiological and -biochemical parameters of in vitro shoot cultures of Lavandula viridis L’Hér and Thymus lotocephalus G. López and R. Morales (Lamiaceae), as well as on phenolic profile and bioactivity (antioxidant and enzyme inhibition capacities). Although some decreases in shoot number and length were observed in response to NPs, biomass production was not affected or was improved in both species. Most NPs treatments decreased total chlorophyll and carotenoid contents and increased malondialdehyde levels, an indicator of lipid peroxidation, in both species. HPLC-HR-MS analysis led to the identification of thirteen and twelve phenolic compounds, respectively, in L. viridis and T. lotocephalus extracts, being rosmarinic acid the major compound found in all the extracts. ZnO and Fe3O4 NPs induced an increase in total phenolic and rosmarinic acid contents in T. lotocephalus extracts. Additionally, some NPs treatments also increased antioxidant activity in extracts from this species and the opposite was observed for L. viridis. The capacity of the extracts to inhibit tyrosinase, acetylcholinesterase and butyrylcholinesterase enzymes was not considerably affected. Overall, NPs had a significant impact on different parameters of L. viridis and T. lotocephalus in vitro shoot cultures, although the results varied with the species and NPs type.

Effect of the addition of iron oxide on the microstructure of ye'elimite

This article is devoted to the description of the microstructure of ye'elimite, calcium aluminates and ferritic phase when iron oxide is present and when the synthesis is carried out at 1300 °C for 3 h. The incorporation of iron in ye'elimite structure (general formula: Ca4Al(6-2x)Fe2xSO16 with x = 0.00 to 1.13) is complete when x < 0.12. Beyond this composition, the ferritic phase (CaO)2(Al2O3,Fe2O3) appears as a minor phase which can develop two forms: needle-like morphology and melt morphology. The presence of iron favors the formation of an iron-rich liquid phase which leads to the growth of ye'elimite grains by material diffusion mechanisms and increases the conversion rate of alumina and calcium aluminates in ye'elimite phase. Also a clear distinction between calcium aluminate and ye'elimite grains is presented.

Foam fractionation removal of multiple per‐ and polyfluoroalkyl substances from landfill leachate

AbstractPer‐ and polyfluoroalkyl substances (PFAS) are a common contaminant in municipal landfill leachate and are recognized as a pollutant on global scale. The present work examined foam fractionation (FF) in batch and continuous modes as an appropriate treatment technique for PFAS removal for the landfill leachate and found stable removal efficiency of greater than 90% for PFOA (C7), PFOS (C8), PFHxS (C6), and PFHpA (C6) and 6:2 FTSA (C6). For other PFAS such as PFNA (C8), PFPeS (C4), PFHxA (C5), PFHpS (C7), and PFBS (C4), a less stable removal between 80% and 50% was achieved while between 50% and 20% removal was observed for EtFOSAA (C8), PFBA (C3), PFDA (C9), FOSA (C8), PFPeA (C4), and MeFOSAA (C8). Increased air flowrate, addition of iron (III) oxide (Fe+3) coagulant, conductivity, and greater untreated leachate PFAS concentration were factors resulting in increased removal efficiency for the majority of PFAS.Article Impact StatementEfficient PFAS removal from landfill leachate using surface‐active foam fractionation treatment with examination of key process parameters.

NH3-SCR performance and SO2 resistance comparison of CeO2 based catalysts with Fe/Mo additive surface decoration

Fe2O3 and/or MoO3 surface decorated CeO2 were designed and synthesized by in situ deposition and incipient wetness impregnation to adjust the SCR catalytic performance and SO2 resistance of CeO2. The addition of iron oxide slightly improved low temperature SCR activity of CeO2-Fe2O3, but resulted in a fast decline of NOx removal efficiency at higher temperatures, which was due to the enhanced NH3 oxidation by surface redox capacity improvement. Surface acidity instead of redox capacity was the main limiting factor for SCR activity of CeO2 and CeO2-Fe2O3. Meanwhile, the introduction of MoO3 increased NOx conversion of CeO2-MoO3 and CeO2-Fe2O3-MoO3 dramatically in a broad temperature range. The increase of catalysts surface acid sites promoted their SCR catalytic performance through Eley-Rideal mechanism. SO2 resistance test indicated the different surface characteristics for the four catalysts resulting from the composition disparity leaded to different deactivation behaviors at 250 °C. The deposition of ammonium sulfate species accounted for the main activity loss of CeO2 and CeO2-Fe2O3, while the sulfation of redox sites was main deactivation reason for CeO2-MoO3 and CeO2-Fe2O3-MoO3. The interaction between SO2 and CeO2/CeO2-Fe2O3 catalysts changed the surface active sites for SCR reaction essentially and MoO3 could inhibited surface sulfation and ammonium sulfate species deposition. The variation behavior of NOx conversion during SO2 resistance test depended on the reaction temperature. All four catalysts show the usability in the presence of SO2 when the reaction temperature is between 300 °C and 400 °C. Considering the complexity of preparation process, catalytic performance and SO2 durability, CeO2-MoO3 catalyst is a better choice for substituting the traditional V-Ti catalyst.

Structural and Electrical Properties of La&lt;sub&gt;0.7&lt;/sub&gt;Ca&lt;sub&gt;0.3&lt;/sub&gt;MnO&lt;sub&gt;3&lt;/sub&gt; /α-Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Composites

Colossal magnetoresistive (CMR) materials have huge potential in modern application and it has been widely used in magnetic sensing industry. From the literature, an incorporation of secondary insulating phase into mixed-valence manganites could improve its extrinsic effect especially low-field magnetoresistance (LFMR). However, nanoparticle addition could lead to substitution and diffusion with its parent compound. In this work, the structural and electrical properties of La0.7Ca0.3MnO3 (LCMO) were investigated by adding the α-Fe2O3 nanoparticle with ratio of 0.00, 0.05, 0.10, 0.15 and 0.20 as the artificial grain boundaries. The LCMO compound has been synthesised using sol-gel route. The samples were chosen to sinter at 800°C to obtain the pure LCMO phase by referring to the thermogravimetric analysis (TGA). The structural properties were investigated by an X-ray diffractometer (XRD) while electrical properties were measured by a four-point probe (4PP) system. XRD patterns showed the coexistence of two phases (LCMO &amp; α-Fe2O3). LCMO crystallised in orthorhombic structure with space group Pnma while α-Fe2O3 exhibited in hexagonal form with space group R-3c. As the content of α-Fe2O3 increases, the resistivity of the samples increases drastically. Nevertheless, the addition of iron oxide has no significant effect on the metal-insulator transition temperature (T­MI). From the XRD and 4PP analysis, it can be deduced that the α-Fe2O3 nanoparticles do not react with LCMO compound and successfully formed the La0.7Ca0.3MnO3 /α-Fe2O3 composites. The resistivity increases when the nano-sized α-Fe2O3 is added into LCMO nanocomposites due to the insulator nature of α-Fe2O3.

Selection of optimal parameters of technological modes for the synthesis of polymer composite materials based on verified mathematical models

In the modern realities of creating structural elements for various purposes, polymer composite materials are widely used. These materials are used in almost all industries, from aerospace, shipbuilding, automotive, and ending with consumer goods. The article shows the need to develop mathematical models that reflect the relationship between mechanical properties and parameters of technological modes for the synthesis of polymer composite materials, to select the optimal parameters of the technological mode of their synthesis. The article discusses the optimization of a group of mechanical properties described by mathematical models built on the basis of a full factorial experiment, in order to obtain the optimal values of the parameters of the technological modes of synthesis of a polymer composite material based on heat-resistant low-molecular-weight synthetic rubber with the addition of ferric iron oxide as a filler. The research method is optimization by the method of successive concessions. Computer experiments have been carried out to optimize the parameters of technological modes for the synthesis of materials. The performed calculations were checked with experimental data, the adequacy of the obtained models was checked.