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This work presents a comprehensive study on the dielectric properties of shellac-based composites with varying filler concentrations of (SiC) and iron (Fe) particles, complemented by scanning electron microscopy (SEM) analysis. Shellac, a natural biopolymer known for its excellent film-forming abilities, biodegradability, and insulating properties, was chosen as the matrix material. The dielectric properties, including permittivity and dielectric loss, are measured by LCR Meter across a frequency range from 100 Hz to 8 MHz to evaluate the effects of filler concentration. This study reveals that the incorporation of SiC and Fe particles significantly enhances the dielectric constant and exhibits complex frequency-dependent behavior in dielectric loss. SEM analysis provided insights into the microstructural changes induced by the fillers, correlating with the observed dielectric properties. The results indicate that the dielectric performance of shellac composites can be effectively tailored through the precise control of SiC and Fe particle concentrations, attributed to interfacial polarization and Maxwell-Wagner-sillars effects. This work underscores the potential of shellac composites as sustainable, high performance dielectric materials for advanced electronic applications, contributing to the development of eco-friendly electronic devices. [ABSTRACT FROM AUTHOR]

The search for novel materials with enhanced characteristics for the advancement of flexible electronic devices and energy harvesting devices is currently a significant concern. Multiferroics are a prominent example of energy conversion materials. The magnetoelectric conversion in a flexible composite based on a piezopolymer layer and a magnetic elastomer layer was investigated. The study focused on investigating the dynamic magnetoelectric effect in various configurations of external alternating and constant homogeneous magnetic fields (L-T and T-T configurations). The T-T geometry exhibited a two orders of magnitude higher coefficient of the magnetoelectric effect compared to the L-T geometry. Mechanisms of structure bending in both geometries were proposed and discussed. A theory was put forward to explain the change in the resonance frequency in a uniform external field. A giant value of frequency tuning in a magnetic field of up to 362% was demonstrated; one of the highest values of the magnetoelectric effect yet recorded in polymer multiferroics was observed, reaching up to 134.3 V/(Oe∙cm). [ABSTRACT FROM AUTHOR]

The driving comfort and safety of the automotive powertrain are significantly related to the performance, lifetime, and functionality of the lubricant. The presented study focuses on investigating the performance loss of the lubricant due to water contamination resulting from environmental influences and iron particles originating from the wear of different machine elements. The main purpose is to determine critical factors that contribute to the degradation of the lubricant, and increase the tendency to NVH behavior, leading to adverse comfort losses to the respective user. Therefore, this performance loss is evaluated by test rig-based analysis of the friction behavior of wet clutches. Due to physical adsorption, a significant impact of water and iron contamination on the degradation of the lubricant is found, while the influence of the energy input is secondary. [ABSTRACT FROM AUTHOR]

This study mainly focuses on investigating the feasibility of utilizing grinding sludge, a by-product of grinding steel plates, as an alternative raw material by filtering and compressing the sludge, removing impurities, adding copper wire bits, and analyzing the resulting samples for improved hardness and corrosion resistance. To improve the hardness and convert the sample to a definite shape, copper wire bits are added to the separated Fe particles during melting. These copper wire bits, which are common scrap available during electrical maintenance, are melted together with Fe particles using the oxy-fuel steel cutting torch at a temperature range of 1539–1600 °C. The melted samples are then characterized using XRD, optical, and scanning electron microscopy analyses. The XRD results confirm the presence of a body-centered cubic lattice structure. Optical and scanning electron microscopy analyses reveal the formation of grains and the mixing of Cu with Fe. Further investigations are conducted to analyze the strength and corrosion properties of the samples. Micro-hardness and electrochemical analysis are performed, and the results show that the addition of copper wire bits improves the corrosion resistance and micro-hardness of the Fe. The fact that the addition of copper wire bits during the melting process improved the corrosion resistance and micro-hardness of the Fe means that the samples can now be sent to the cupola furnace for melting and reuse. This is a sustainable approach that will allow for the responsible disposal of the materials, while also potentially reducing the need for new materials in future production processes.

The invention of magnetorheological abrasive finishing (MRAF) techniques has been prompted by the ever-increasing demand for nano-finished exterior surfaces of cylindrical work samples. In the present study, a novel form of the MRAF system to nano-finish the exterior cylindrical surfaces of various diameters has been devised and their finishing mechanism is discussed. The finishing experiments have been carried out to examine the finishing capabilities of newly devised MRAF system. Taguchi's parameter design approach has been employed to find the optimal combination of finishing parameters to achieve high-quality surface of S.S.-316 L cylindrical work-sample. The obtained results have been analyzed statistically which demonstrate that the chosen parameters namely F-to-S iron ratio, d.c. supply, work sample rotational speed and linear feed rate have significant effect on the percentage change in average surface roughness (%ΔRa). The effect of finishing time on Ra has also been explored, with the findings revealing that a minimum Ra value of 0.074 µm was attained after 60 minutes of finishing time, demonstrating the developed MRAF process's superior capabilities. [ABSTRACT FROM AUTHOR]

Multilayered magnetoelectric materials are of great interest for investigations due to their unique tuneable properties and giant values of magnetoelectric effect. The flexible layered structures consisting of soft components can reveal lower values of the resonant frequency for the dynamic magnetoelectric effect appearing in bending deformation mode. The double-layered structure based on the piezoelectric polymer polyvinylidene fluoride and a magnetoactive elastomer (MAE) with carbonyl iron particles in a cantilever configuration was investigated in this work. The gradient AC magnetic field was applied to the structure, causing the bending of the sample due to the attraction acting on the magnetic component. The resonant enhancement of the magnetoelectric effect was observed. The main resonant frequency for the samples depended on the MAE properties, namely, their thickness and concentration of iron particles, and was 156–163 Hz for a 0.3 mm MAE layer and 50–72 Hz for a 3 mm MAE layer; the resonant frequency depended on bias DC magnetic field as well. The results obtained can extend the application area of these devices for energy harvesting. [ABSTRACT FROM AUTHOR]

In recent years, due to the increase in the consumption of electric energy worldwide, the generation of sustainable energy has become the focus of several scientific investigations. In this scenario, this project will propose a new technology for energy generation, based on the use of residue of Agate Stone Powder. It is worth noting that, currently, there is still no regulation for the disposal of these materials, occurring most of the time inadequately. Besides this, an iron-based particle will also be used, in order to build a cement artifact that works as an energy generator. It is expected that, at the end of the project, the developed prototype will be able to generate electrical energy in a satisfactory manner. The built prototype will have to be tested in a state of super humidity, that is, totally submerged in water, in order to evaluate its quality and efficiency. The final material confectioned, because it is a material capable of generating energy through humidity, receives the name of hygrogenerator and awakens great future possibilities for the development of new technologies, besides contributing to the sustainability of the environment. [ABSTRACT FROM AUTHOR]

The driving comfort and safety of the automotive powertrain are significantly related to the performance, lifetime, and functionality of the lubricant. The presented study focuses on investigating the performance loss of the lubricant due to water contamination resulting from environmental influences and iron particles originating from the wear of different machine elements. The main purpose is to determine critical factors that contribute to the degradation of the lubricant, and increase the tendency to NVH behavior, leading to adverse comfort losses to the respective user. Therefore, this performance loss is evaluated by test rig-based analysis of the friction behavior of wet clutches. Due to physical adsorption, a significant impact of water and iron contamination on the degradation of the lubricant is found, while the influence of the energy input is secondary.

The paper proposes a simple way to simultaneously modify iron particles with both silica and surfactant molecules, which involves wet ball milling of iron with silica glass and surfactants (stearic and n-perfluorononanoic acid). The structure of interfaces in the as-modified particles was analyzed by XPS and NEXAFS spectroscopies. Silica glass is finely powdered and its mechanical rubbing into ductile iron particles induces chemical transformations at interfaces between iron and silica with the formation of various products. Surfactants are then adsorbed on silica-enriched particle surfaces. In the case of stearic acid, the surfactant is attached through the hydrogen bonds between the carboxyl and silanol groups of the outermost hydrated layer, whereas n-perfluorononanoic acid is adsorbed through carboxylates formed with iron atoms in the outer silicate layer. The angle-dependent NEXAFS analysis has shown predominantly up-right arrangement of the surfactant molecules with respect to the particle planes. Hybrid layers of silica and n-perfluorononanoic acid exhibit better corrosion resistance than those comprised of only SiO2 or only n-perfluorononanoic acid, which contrasts to stearic acid molecules providing proper anticorrosive efficiency alone.

The carbonaceous precursor was obtained via pyrolysis of commercial aramid polymer (Kevlar). Additionally the precursor was activated at 1000°C in CO2 atmosphere for different times. Obtained materials were characterised by BET; XPS; SEM and optical microscopy. The sorption capacities were determined by temperature swing adsorption performed in TGA apparatus for CO2 and C2H4 gases. The obtained materials exhibit high difference in sorption of these gases i.e. 1.5 and 2.8 mmol/g @30°C respectively and high SSA ~1600 m2/g what can be applied in separation applications. The highest uptakes were 1.8 and 3.1 mmol/g @30°C respectively. It was found that the presence of oxygen and nitrogen functional groups enhances C2H4/CO2 uptake ratio.

The presented work describes the autoxidation of alpha-pinene for the first time using a catalyst based on activated carbon from biomass with introduced Fe. The raw material for the preparation of the carbon material was waste orange peel, which was activated with a KOH solution. The following instrumental methods characterized the obtained catalyst (Fe/O_AC):N2 adsorption at 77 K, XRD, UV, SEM, TEM, X-ray microanalysis, and catalytic studies. It was shown that the Fe/O_AC catalyst was very active in the autoxidation of alpha-pinene. The main reaction products were: alpha-pinene oxide, verbenone, verbenol, and campholenic aldehyde.

Additives play an important role in the recycling of complex refractory iron ore by coal-based reduction to improve the self-sufficiency rate of the ore. In this work, the influence mechanisms of CaF2, Na2CO3, and MgCO3 additives on the coal-based reduction of complex refractory iron ore were studied by x-ray diffraction, thermogravimetry and differential scanning calorimetry, scanning electron microscopy, and energy dispersive spectrometry. The results indicate the three additives could greatly improve the quality of reduction and magnetic separation products. A reduction product metallization degree 93.42%, iron grade 91.23%, and iron recovery 95.48% were obtained under conditions of CaF2 dosage 6%, reduction temperature 1225 °C, and reduction time 50 min. These results were 3.38%, 8.09%, and 0.39% higher, respectively, than could be obtained without additives. The CaF2, and the Na2O and MgO produced by the decomposition of Na2CO3 and MgCO3, could not only replace the FeO from (Mg,Fe)SiO4 and FeAl2O4, but also react with SiO2 and Al2O3 in ore to form their corresponding complex compounds. Moreover, all compounds were benefitted by the increase of the FeO content. The F− ion could replace the O2- ion in the silicon oxygen tetrahedron to reduce the viscosity and surface tension of reduced ore, thus reducing the resistance of iron particle aggregation and growth. In addition, the formation of a local micro melting phase under the action of additives could promote the diffusion of crystalline particles, which is more conducive to the reduction of iron minerals and the formation and growth of iron particles. [ABSTRACT FROM AUTHOR]

The exploitation of refractory iron ores has become increasingly important around the world because of the rapid depletion of easy-to-process iron ores. Ironsand is extensively distributed in the coastal areas of Indonesia, China, and New Zealand, and can provide an alternative to conventional iron ores. Although the composition of ironsand is partially dependent on its location and position, it approximates that of titanomagnetite (Fe3-xTixO4) containing ~ 60% total Fe (TFe). However, the conventional smelting route for smelting beach titanomagnetite concentrate with carbon uses a blast furnace to produce pig iron and titanium slag, which has many disadvantages. First, the smelting process requires lots of coke and a high temperature. Second, sinter blend allows for the addition of only a small amount of beach titanomagnetite concentrate to ensure the desired sintering characteristics. Therefore, in order to efficiently utilize beach titanomagnetite, the processes of direct reduction followed by magnetic separation are generally applied to recover iron. In addition, additives such as CaO, CaCO3, and NaCO3 are often used in the reduction roasting process. These additives may improve the reduction characteristics or facilitate the growth of iron particles to some extent. In order to study the effect of the additive CaO on the direct reduction and magnetic separation of beach titanomagnetite concentrate which contains 58.58% of TFe and 12.04% of TiO2, the mechanisms were investigated by gas composition of CO and CO2, gasification rate of total reaction, CO partial pressure, metallization rate, mineral composition and so on. The results indicate that adding CaO can improve the gasification rate of reductant and facilitate the reduction of titanomagnetite, which improves the generation of CO2 gas and decreases the CO partial pressure. Besides, CaO can participate in solid-solid reaction, reduce FeO content in Ti-containing mineral and facilitate the migration and enrichment of Ti and Fe components, which promote the growth of metallic iron particles. Thus, adding CaO is good for the separation and recovery of Fe and Ti by grinding and magnetic separation.

The particles used in magnetorheological polishing (MRP) fluid are the key components of the magnetorheological (MR) finishing processes. The rotational magnetorheological honing (R-MRH) process is recently developed as a highly productive MR finishing process which is used for finishing the internal surface of the industrial cylindric components. The involvement of micron-sized abrasive particles of MRP fluid in the finishing operation results in the invisible observation of the finishing mechanism which enables the urge of analyzing the motion of the particles during the present R-MRH process. Therefore, the effect of motions of the MRP-fluid's particles is analyzed for nano-finishing performance on the inside surface of the cylindric workpieces. The motions performed by active abrasive particles on the inside surface of the rotating hollow cylindric workpiece cause a higher finishing rate. The effects of particle motions on the reduction in surface roughness and improvement in surface morphology confirm the usefulness of the R-MRH process. The surface finish with the effect of the particles' motions of the MRP-fluid in the R-MRH process on the stationary workpiece's inner surface is achieved upto 100 nm from 420 nm of the initial ground surface in 60 min of finishing. Whereas, the same aforementioned surface of the rotating workpiece is finished upto 50 nm from the same initial ground surface in only 40 min of finishing with the effect of the particles' motions of the MRP-fluid. The improvement in the surface finish is also noticed through the scanning electron micrographs in this work. The significant change in surface finish obtained in experimentations confirms the integrity of the analytical study conducted for understanding the effects of motions of particles while finishing with the R-MRH process. [ABSTRACT FROM AUTHOR]

The carbonaceous precursor was obtained via pyrolysis of commercial aramid polymer (Kevlar). Additionally the precursor was activated at 1000°C in CO2 atmosphere for different times. Obtained materials were characterised by BET; XPS; SEM and optical microscopy. The sorption capacities were determined by temperature swing adsorption performed in TGA apparatus for CO2 and C2H4 gases. The obtained materials exhibit high difference in sorption of these gases i.e. 1.5 and 2.8 mmol/g @30°C respectively and high SSA ~1600 m2/g what can be applied in separation applications. The highest uptakes were 1.8 and 3.1 mmol/g @30°C respectively. It was found that the presence of oxygen and nitrogen functional groups enhances C2H4/CO2 uptake ratio. [ABSTRACT FROM AUTHOR]

The present study reports a benign approach to prepare citrate capped iron particles using juice of a lemon fruit. Resultant particles were subjected to detailed adsorption studies for removal of arsenite aqueous solution of defined concentration. The planer reflection of XRD analysis suggested that iron particles were crystalline in nature. FT-IR study suggested that functional groups like -NH2, -NO2, -CO, and --CS were involved in arsenite ion sorption. The composite removal efficiency for As (III) was found to be 88.58%, at pH 4.5, with contact time of 30 min and temperature at 30°C. Data of adsorption were analyzed using various parameter like isotherm models, thermodynamic and kinetic models. Chemisorptions resulted in to formation of monolayer arsenite ions over the surface of prepared iron particles with maximum adsorption capacity; 55.53 mg/gm. Adsorbent hold good promises to remove arsenic from contaminated water. [ABSTRACT FROM AUTHOR]

Longitudinal and transversal joints in asphalt roads are permanently present in any pavement structure due to the construction procedures applied nowadays. These types of joints form discontinuities in the aggregate skeleton affecting the traffic loads distribution. Nevertheless, conventional joints construction procedures are basically focused on sealing the interface of the joint to avoid water infiltration. This study investigates the influence of the compaction temperature and the geometry of different joint designs. In particular, it proposes a new approach where iron particles are added to the asphalt mixture for allowing an induction heating process that locally increases the temperature either during the compaction of the joint or for an extra-compaction after construction of the joint. Results confirmed that high temperature during compaction of the joint leads to a better overall performance and that angular joints improve the interlock between the two interfaces. Likewise, it was shown that an extra-compaction process can significantly enhance the resistance of untreated joints against fracture and adhesion loss. [ABSTRACT FROM AUTHOR]

Magnetic Abrasive Finishing (MAF) process is an advanced finishing method involving a dry medium comprising iron and non-magnetic abrasive particles. When this mixture is brought in the magnetic field, it forms a very fine, multiple, and flexible abrasive brushes, which can be used for finishing the magnetic as well as non-magnetic materials such as aluminum. For performing finishing operation on aluminum shaft, novel finishing tool having the fixtures for holding the workpiece and other comprising part have been designed, developed and fabricated. These fixtures are attached to a Lathe machine and moved along the length of the rotating workpiece. The non-magnetic material, which is chosen as aluminum, and the finishing operation is performed on it. Minimum surface roughness 96 nm after the actual surface finish of 400 nm with the change in percentage Ra 76% is achieved using the novel finishing tool. [ABSTRACT FROM AUTHOR]

Iron particles ranging from 50 to 150 µm are incorporated in an elastomer matrix to obtain magnetorheological elastomer (MRE) composites, aiming to investigate their effects on the surface morphology. The isotropic and anisotropic distribution of fillers are estimated in MRE composites. A simulation analysis is carried out to predict the particle distribution in MRE composites, and a correlation between the experimental observation and simulation analysis is established. The volume fraction of 30 vol% is chosen as the optimal quantity for the filler amount in elastomer composite. [ABSTRACT FROM AUTHOR]

• Laser transmission welding of polycarbonate with polystyrene using iron powder has been studied. • Effects of laser power and scan speed are analyzed on weld strength and bond morphology. • The results show that weldments failed by the brittle fracture due to the more brittle nature of polystyrene. • The mechanical interlocking of iron particles and polymeric bridges formed by polymer molecular interdiffusion improves weld strength. This study aims to investigate the laser transmission welding (LTW) of polystyrene and polycarbonate using an electrolytic iron powder absorber. For this purpose, the experiments are performed to explore the effect of laser power and scan speed on the weld strength and bond morphology. The lap shear tests are conducted to obtain the breaking force and ductility of the welded joints. The fractured surface and cross-sections are analyzed by scanning electron and optical microscopy to investigate the bond morphology and bonding mechanism of the weldments. The results show that laser power and scan speed significantly affect the weld strength and ductility of the joints. The optical and scanning electron micrographs clarify that mechanical anchoring of iron particles, polymeric interdiffusion, and small bubbles enhance the bond strength but thermal degradation, burning, and large bubbles negatively affect the bonding. [ABSTRACT FROM AUTHOR]

To realize light-weight materials with high strength and ductility, an effective route is to incorporate strong and stiff metallic elements in light-weight matrices. Based on this approach, in this work, magnesium–iron (Mg-Fe) composites were designed and characterized for their microstructure and mechanical properties. The Mg-Fe binary system has extremely low solubility of Fe in the Mg-rich region. Pure magnesium was incorporated with 5, 10, and 15 wt.% Fe particles to form Mg-Fe metal–metal composites by the disintegrated melt deposition technique, followed by hot extrusion. Results showed that the iron content influences (i) the distribution of Fe particles in the Mg matrix, (ii) grain refinement, and (iii) change in crystallographic orientation. Mechanical testing showed that amongst the composites, Mg-5Fe had the highest hardness, strength, and ductility due to (a) the uniform distribution of Fe particles in the Mg matrix, (b) grain refinement, (c) texture randomization, (d) Fe particles acting as effective reinforcement, and (e) absence of deleterious interfacial reactions. Under impression creep, the Mg-5Fe composite had a creep rate similar to those of commercial creep-resistant AE42 alloys and Mg ceramic composites at 473 K. Factors influencing the performance of Mg-5Fe and other Mg metal–metal composites having molybdenum, niobium, and titanium (elements with low solubility in Mg) are presented and discussed.

Magnetorheological elastomer (MRE) specimens were prepared to find the optimum compressive characteristics using different types and amounts of iron powder. A magnetic field of up to 2 T was applied during vulcanization. Among the four types of iron powders, the specimen with round‐shaped carbonyl iron powder and small grain size shows higher magnetic effects than that with bigger and irregularly shaped electrolyte iron powder. However, the compressive modulus of the rubber with electrolyte iron powder is higher without magnetic treatment at a given amount. In general, the bigger and irregularly shaped iron particles tend to move slowly and produce nonuniform distribution when a magnetic field is applied. The experimental results show that the mechanical properties are better when applying a magnetic field of 1.5 T compared with 2.0 T during the specimen vulcanization. Applying a magnetic field of 300 mT during the compression test enhanced the compressive modulus by 12% to 15%. The rate of increase of the modulus decreased exponentially with prestrain. [ABSTRACT FROM AUTHOR]

[Display omitted] • A thermal plasma chemical looping system is modelled for iron fuel particles. • The energetic performance of the system was analysed via equilibrium models. • Hydrogen was used to reduce the iron to eliminate CO 2 emission. • The self-sustaining factor was 0.8 at a combustor temperature of 2273 K. • The sustainability assessment showed a good linear flow index of 0.355. In the present research, a novel process was proposed and assessed using an equilibrium thermochemical modelling study to evaluate the performance of a combined disruptive technology of thermal plasma and thermochemical looping to utilise hydrogen for iron reduction processing. The study was aimed at conducting a high-level power performance assessment of the process by integrating a built-in power block with a focus on a novel equilibrium thermal plasma technology for reducing iron scrap particles. The effect of thermal plasma operating parameters such as temperature (1000 °C < T < 1800 °C) and hydrogen-to-iron ratio in the feed stream to the thermal plasma reactor (0 < H 2 /metal < 20) on the performance of the system was numerically investigated using Aspen coupled with Matlab. Also, the self-sustaining factor was evaluated coupled with a quantitative analysis of the sustainability and lifecycle of the process aiming at better understanding the impact of the proposed system on the environment. Results showed that the system is crucially sensitive to the ratio of H 2 /metal such that the overall power demand of the reactor can change in a way that the dominant regime of the plasma can change from endothermic (partial reduction of iron) to exothermic (complete reduction, combustion of iron) once the hydrogen to metal ratio exceeds ∼ 2.5. It was also identified that an increase in the temperature of the combustor decreased the power demand for the thermal plasma reactor. Similarly, with increasing the temperature, a ramp-up in the self-sustaining factor was observed reaching 0.8 showing that 80 % of the energy of the auxiliaries can be maintained using the built-in heat recovery and power block. The thermal efficiency of the system was also a strong function of the H 2 /metal ratio reaching ∼ 0.4 at the H 2 /metal ratio of ∼ 2.5 reflecting the fact that the proposed process efficiency is within the state-of-the-art power production systems. The sustainability assessments showed that the process offers a high circular economy capability of the process with above-the-average lifetime and Material Circularity Indicator values. [ABSTRACT FROM AUTHOR]

Iron is a promising energy carrier with the potential to store substantial amounts of energy over extended time periods with minimal losses. For instance, the energy from green hydrogen sources can be used to reduce iron oxides, be stored or transported, and thus be regained by exothermic oxidation of the iron. This work explores the influence of oxygen partial pressure and temperature on the oxidation process in a fixed-bed reactor. Furthermore, the analysis extends to the reduction of oxidized iron particles at varying temperatures. The experimental findings highlight that both oxidation and reduction progress through the fixed-bed reactor as distinct reaction fronts. In the oxidation process, the speed of the reaction front increases with rising oxygen content and temperature, resulting in a higher reaction rate and a correspondingly increased heat release. Conversely, the reaction rate for reduction experiences a notable decrease for 600 °C and 700 °C. The reprocessability of the iron powder was validated for up to 16 cycles under the optimal reaction conditions established. Furthermore, it was demonstrated that the performance improves with an increasing number of cycles. This improvement is attributed to the formation of pores due to density changes and the subsequent creation of a larger surface area, mitigating the negative effects of sintering and agglomeration. [ABSTRACT FROM AUTHOR]

To explore the coalescence, growth and settling behavior of metallic Fe droplets under the dynamic oxidation condition, the effects of oxidation time, air stirring intensity and pure oxygen oxidizing on the coalescence of metallic Fe were investigated in this paper. The changes in temperature and viscosity of the molten slag were studied during the dynamic oxidation process, and the settling speed of metallic Fe was calculated. It is indicated by lab and 1200 kg pilot-scale experiments that low valence titanium is oxidized by blowing the oxidizing gas. As the temperature increases, the viscosity of the slag decreases, which accelerates the coalescence, growth and settling of metallic Fe droplets. With a longer oxidizing time, low valence titanium and (FeO) finally almost vanish, and metallic Fe droplets are oxidized, resulting in the decrease of metallic Fe recovery. The judgment of the oxidation end point depends on the (FeO) and low valence titanium content.

Aeolian dust plays an important role in climate and ocean processes. Particularly, Saharan dust deposition is of importance in the Canary Current due to its content of iron minerals, which are fertilizers of the ocean. In this work, dust particles are characterized mainly by granulometry, morphometry and mineralogy, using image processing and scanning northern Mauritania and the Western Sahara. The concentration of terrigenous material was measured in three environments: the atmosphere (300 m above sea level), the mixed layer at 10 m depth, and 150 m depth. Samples were collected before and during the dust events, thus allowing the effect of Saharan dust inputs in the water column to be assessed. The dominant grain size was coarse silt. Dominant minerals were iron oxy-hydroxides, silicates and Ca-Mg carbonates. A relative increase of iron mineral particles (hematite and goethite) was detected in the mixed layer, reflecting a higher permanence of iron in the water column despite the greater relative density of these minerals in comparison with the other minerals. This higher iron particle permanence does not appear to be explained by physical processes. The retention of this metal by colloids or microorganisms is suggested to explain its long residence time in the mixed layer.

The article presents a detailed study and characterization of the oxide layers on the surface of iron particles of various sizes. Ten iron samples with a size range from a few nm to 50 µm were studied in detail using SEM, TEM, XRD, and TGA analysis. The composition of the multiphase oxide layers on the powder surface was investigated. The main components of the oxide layer were FeO, Fe3O4, and Fe2O3. By the obtained data, a model for the calculation of a multiphase oxide layer thickness on the surface of iron particles was proposed. The proposed model was validated and can be used for the characterization and certification of micro– and nanoscale iron particles.

The effect of iron-containing solid wastes from metal working, asphaltene and paraffin deposits, and that of an electromagnetic field on activated low-temperature viscosity breaking of bituminous oil has been studied. It has been found that the use of additives and an electromagnetic field makes it possible to reduce the temperature of oil cracking to 397°C, increase the yield of light petroleum products (gasoline, diesel, and gas oil fractions), and increase the quality of produced fractions. [ABSTRACT FROM AUTHOR]

It is well known that particles, especially conducting particles, have a detrimental effect on the dielectric strength of transformer oil. This article investigates the influence of iron particles on the breakdown voltage of transformer oil. The breakdown voltage of transformer oil contaminated with iron particles of different median diameters and quantities was measured at pulsating DC voltage. For comparison, identical experiments were performed at AC and DC voltage, respectively. The Weibull distribution was adopted to analyze the breakdown voltage data and thus the effect of particle number and particle size on the breakdown voltage of transformer oil was obtained. The experiment results showed that the breakdown voltage of transformer oil decreases with an increase of the particle number and particle size. The breakdown voltage of contaminated oil is smaller when there is DC component contained in the applied voltage, which is because of the increasing possibility of bridge formation in transformer oil with the presence of DC voltage. The limit of particle number was also calculated for transformer oil subjected to pulsating DC voltage and found to be lower than that at AC voltage, suggesting that the limit of particle number should be individually defined for converter transformer oil. [ABSTRACT FROM AUTHOR]

A hot melt adhesive - mainly used for bonding plastic component in automotive field - was modified with different ironbased particles to give it a reversible behaviour. Mechanical and physical properties of these reversible adhesives were experimentally assessed in the work. The modified adhesives, coupled with electromagnetic induction, are able to guarantee separation of the joints without any damage to the substrates for recycling, reuse or repairing of components. Single lap joint specimens were prepared using epoxy/glass fibres substrates and tests were carried out on neat and modified adhesive with 5% weight of iron and iron oxide. Three different Fe particles size were tested: 450 µm, 60 µm and 1-6 µm. The particles size of iron oxide was 50 nm. Separation was studied using single lap joint specimens under electro-magnetic induction. Experimental results showed that the maximum peak load decreases when the average particles sizes increase. The peak loads of the smallest particles were equal to the ones of the pristine adhesive. The elongation of the adhesives increases when the adhesive is modified with both iron and iron oxide particles. Finally, experimental tests on single lap joints coupled with electro-magnetic induction showed that separation of the substrates is possible using iron oxide particles. Electro-magnetic tests conducted on particles alone, helped to understand that bigger particles are able to overcome the melting temperature of the adhesive but hot-melt adhesives modified with these particles are not able to reach the melting. These tests showed that the number of particles into the adhesive matrix is very important for this kind of tests. [ABSTRACT FROM AUTHOR]

Atmospheric iron (Fe) is an important micronutrient controlling marine primary productivity, which affects marine ecosystems and biogeochemistry. However, few studies have reported the abundance of aerosol Fe and its associated mixing state and solubility in marine environments. Here, aerosol samples were collected over the Bohai Sea and the Yellow Sea near East China during a research cruise. The results show that anthropogenic Fe-containing particles accounted for 9.3% of the total observed marine particles with diameters from 0.1 to 7 μm. Almost all of the Fe-containing particles (94%) were internal mixtures of FeO x particles (i.e., Fe-rich/fly ash) and secondary aerosols (e.g., nitrate, sulfate, and organics). During their aging process, the FeO x particles grew approximately tenfold in size from 100 nm to 1 μm by acquiring a thick secondary aerosol coating after one to two days of transport. The elemental mapping on a per-particle basis showed that the secondary aerosol coating likely homogeneously contained little Fe, suggesting that the acidic coating solubilized Fe via an acid dissolution process in the marine air. Therefore, acid dissolution of metal aerosols in anthropogenic smog should be considered in studies on the biogeochemical cycle between coastal marine air and ocean productivity. • FeOx particles accounted for 9.3% of the observed marine particles. • Most of the FeOx particles (94%) were internally mixed with secondary aerosols. • FeOx particles acquired secondary coating tenfold after one to two days of transport. • The acidic coating solubilized Fe via an acid dissolution process in the marine air. [ABSTRACT FROM AUTHOR]

In this study, iron (Fe) particles are attaining importance for their vital properties and multifunctional applications including hazardous waste treatment, catalytic degradation biomedical treatments, microwave adsorption and medical diagnostic. These particles were prepared by using mango leaves, rose leaves, neem leaves, carom seeds and clove buds through eco-friendly green synthesis under constant stirring and atmospheric pressure at 70 °C temperature. The synthesized Fe particles are in zero valent oxidation state. Different plant extracts plays a vital in reduction and stabilization of nanoparticles along with particular amount polyvinylpyrrolidone (PVP), instead of polyvinyl alcohol (PVA) act as stabilizing agent. The prepared nanoparticles were analyzed by using SEM, XRD, EDX, FTIR, and Uv–vis spectroscopy. The experimental results revealed that size of Fe particles increased with increasing concentration of PVP. Higher concentrations of Fe particles in the prepared sample are confirmed by the FTIR spectra peak depth at 3338 cm −1 . Remarkable effect of PVP on the surface of Fe particles investigated by using UV–visible spectrometer (UV-VIS) such that the first absorbance peak observed at 320–325 nm and the second peak observed at 470–475 nm. XRD spectra show the pure (FCC) Fe particles, which are crystalline in nature with peaks at 43.37° with planer reflections of 400, where EDX confirmed the purity of Fe particles and elemental percentage. [ABSTRACT FROM AUTHOR]

A new type of conductive aggregate was prepared by the calcination of magnetically separated fly ash (MSFA). The effects of the calcination atmosphere, calcination temperature, and iron oxide content on the electrical resistivity were studied. Experimental results show that the optimal calcination conditions are a reducing atmosphere and a temperature of 1150 °C. Iron oxides were reduced to iron by the reducing atmosphere and formed a continuous electrical path; the conductive mechanism is electron conduction. The water absorption and apparent density of the optimal conductive aggregate were 5%, and ∼2.0 g/cm 3 . The new series of conductive aggregates provided good electrical conductivity (volume resistivity of all conductive aggregates < 10 Ω-cm). [ABSTRACT FROM AUTHOR]

Rivers are significant contributors of Fe to the ocean. However, the characteristics of chemically reactive Fe remain poorly constrained, especially in large Arctic rivers, which drain landscapes highly susceptible to climate change and carbon cycle alteration. The aim of this study was a detailed characterisation (size, mineralogy, and speciation) of riverine Fe-bearing particles (>0.22 µm) and colloids (1 kDa–0.22 µm) and their association with organic carbon (OC), in the Lena River and tributaries, which drain a catchment almost entirely underlain by permafrost. Samples from the main channel and tributaries representing watersheds that span a wide range in topography and lithology were taken after the spring flood in June 2013 and summer baseflow in July 2012. Fe-bearing particles were identified, using Transmission Electron Microscopy, as large (200 nm–1 µm) aggregates of smaller (20–30 nm) spherical colloids of chemically-reactive ferrihydrite. In contrast, there were also large (500 nm–1 µm) aggregates of clay (illite) particles and smaller (100–200 nm) iron oxide particles (dominantly hematite) that contain poorly reactive Fe. TEM imaging and Scanning Transmission X-ray microscopy (STXM) indicated that the ferrihydrite is present as discrete particles within networks of amorphous particulate organic carbon (POC) and attached to the surface of primary produced organic matter and clay particles. Together, these larger particles act as the main carriers of nanoscale ferrihydrite in the Lena River basin. The chemically reactive ferrihydrite accounts for on average 70 ± 15% of the total suspended Fe in the Lena River and tributaries. These observations place important constraints on Fe and OC cycling in the Lena River catchment area and Fe-bearing particle transport to the Arctic Ocean. [ABSTRACT FROM AUTHOR]

The curing behaviour and the mechanical behaviour of susceptor-assisted induction-cured adhesively bonded joints has been investigated. Induction Heating (IH) was established by mixing Iron particles into a two component epoxy paste adhesive. The effect of different process parameters, such as particle content, coupling distance and coil current, on the IH curing process was evaluated by experimental tests and simulation of the induction heating process in COMSOL multiphysics. The process simulation showed that hysteresis losses has a major contribution for the heat generation of IH using Iron particles. Differential scanning calorimetry (DSC) analysis was used to assess the effect of susceptor particles on the cure behaviour of the adhesive. The results showed that the Iron particles do not interfere with the curing process of the epoxy adhesive in scope. The mechanical performance was evaluated through Single Lap-Shear (SLS) testing at different volume-percentages of Iron particles in combination with glass fibre reinforced plastic (GFRP) adherends. Induction-cured SLS samples were compared with conventional oven-cured SLS samples. In the oven cured samples, the addition of Iron particles resulted in a decrease in the lap-shear strength of 15% to 20%, even for a volume-percentage as low as 0.5%. An additional increase in particle content up to 7.5 v% did not show any additional reduction in the lap-shear strength. Furthermore, results show that when curing the adhesive layer from the inside, as in the susceptor-assisted induction heating, the lap-shear strength is 6% higher than in oven-cured samples (curing the adhesive layer from the outside). [ABSTRACT FROM AUTHOR]

The preparation of Fe-particles by reduction of FeSO4 with either sodium borohydride or lithium triethylborohydride in water, and reverse micelles in rapeseed and mineral oil phases is described in electrochemical terms. The influence of surfactants on the electrochemical parameters and resulting size of iron particles was studied as well. The resulting size of Fe-particles synthesized in water (with and without surfactants) correlates with the determined values of open circuit potential (OCP): the more negative OCP, the obtained Fe-particles are bigger, because values of OCP correspond to different range of polarization determined for the reduction of Fe2+. The sizes of Fe-particles synthesized in water or oil phases without surfactants using LiBEt3H are less than using NaBH4 because of electrochemical factors. By varying oils and surfactants it is possible to obtain opposite results as in water phase: smaller Fe-particles obtained using NaBH4 than using LiBEt3H. It is explained by the simultaneous influence of electrochemical and steric stabilization factors, and the last one becomes dominating in some cases.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2429

MR(magnetorheological) devices for vehicle applications requires the consistent control performance and the reliable operation. However, the corrosion of iron particles consisting the MR fluid can significantly affect on MR properties. This paper presents an effect of the MR particle corrosion on the performance of MR fluids such as shear stress magnitude which is directly concerned with control performance. As a first step, MR particles are corroded by water-calcium chloride solution. The resulting MR particles are examined by scanning electron microscope (SEM) and their molar ratios are analyzed by the energy dispersive X-ray analysis (EDAX). By dispersing the corroded MR particles into silicone oil, the corroded MR fluid is synthesized for evaluation of MR effect change. A rotational viscometer is adopted to measure shear stress magnitude. Finally, it is demonstrated how much the corrosion affect on performances by comparing the normal MR fluid to the corroded MR fluid, from which performance investigation of the MR devices containing the corroded MR particles will be studied in the second phase of this study. [ABSTRACT FROM AUTHOR]

Carbon nanofibers (CNFs) is one of carbon material type and has received fascinating attention to be used a metal support. In this study, two portions of samples were prepared separately into pristine CNFs (CNF-P) and functionalized CNFs (CNF-2RX) sample. CNF-2RX sample was refluxed in HNO 3 solution for 2 h. Subsequently, surface properties for both samples were evaluated by BET, FESEM-EDX, TEM, XPS, and FTIR. Results have shown significant differences of surface properties between CNF-P and CNF-2RX. It revealed that CNF-2RX which has been introduced to HNO 3 treatment was increased 12.43% of surface area, pore volume and formed oxygen surface group (carboxylic group) compared to pristine CNFs. Then performance of iron distribution and loaded onto two different types of supports which are Fe/CNF-P and Fe/CNF-2RX by DP method were characterized by TEM, BET and XRF. These results revealed high loaded of iron were obtained for both samples (Fe/CNF-P with 8.43 wt. % and 9.15 wt. % for Fe/CNF-2RX) but only Fe/CNF-2RX shown uniform and close distribution between iron particles. Deposition of iron particles at Fe/CNF-2RX were found to be at internal surface which cause decrease of support surface area and pore volume with confirmed that strong interaction by adsorption between iron and oxygen surface group at CNF-2RX surface have obtained. [ABSTRACT FROM AUTHOR]

This work assessed the use of industrial iron waste in the activation of persulfate (PS) (100 μM) into sulfate radicals (SRs) for the removal of ranitidine (RAN) (28.5 μM) from aqueous systems. The released iron corrosion products (ICPs) e.g. mainly Fe 2 + species are responsible of PS activation. The optimal molar ratio of Fe 2 + :PS was found to be 1:1. A comparative study between industrial iron (iFe) and commercial iron (cFe) at 2 successive experimental runs showed that iFe has some advantages over cFe in terms of sustainability and less sludge formation. At low load of iFe (1 mg/20 mL), RAN removal was 95% over one hour of reaction time with a ratio of released Fe 2 + :PS of only 0.16:1.00. This system was evaluated at different ionic strength [ I ] conditions with NaClO 4 neutral electrolyte, as well as in the presence of Cl - and Br - , the main seawater components. Results showed that at elevated [ I ] conditions, the rate of RAN degradation has decreased. However, in the presence of Cl - and Br - , with optimum levels of 1.0 mM at [ I ] = 100 mM, RAN removal was enhanced rather than quenched. The total organic carbon (TOC) was analyzed at different PS:iFe molar ratios. Although degradation was successful at a very low iFe load, mineralization was negligible. However, RAN co-precipitation with in-situ formed ICPs improved TOC removal at higher iFe levels. The HPLC/MS chromatograms showed the presence of an oxidized RAN intermediate detected at 331 m/z that dissipated gradually throughout the treatment. [ABSTRACT FROM AUTHOR]

Different homemade iron-activated carbon catalysts (Fe/AC) have been studied in the CWPO of phenol at mild conditions (atmospheric pressure and 50 °C). Both iron content and the way to introduce iron active phase in Fe/AC catalysts were analyzed to select the most stable and efficient activated carbon-supported iron catalyst. The major differences were found on their surface properties, mainly those related to iron distribution and iron particle size. Catalysts prepared by two-consecutive steps of impregnation, regardless of iron content, always presented lower leaching phenomena of iron to the reaction medium than those prepared by one-step wetness impregnation. This higher stability could be indicating an improved metal-support interaction as a consequence of the two-step methodology used to incorporate the iron, which leads to the formation of small iron particles very homogeneous in size (≈3 nm). The best performance balanced between activity and stability was obtained with 2% iron 2-steps catalyst (2sFe/CN) which gave rise to complete removal of phenol after 60 min, maximal reduction of TOC content and optimal use of the stoichiometric amount of H 2 O 2 added during batch experiments at 50 °C, atmospheric pressure, 500 mg L −1 catalyst loading, 100 mg L −1 and 500 mg L −1 of phenol and hydrogen peroxide concentrations, respectively, at pH 0 = 3. The study of H 2 O 2 decomposition in the presence of an excess of MeOH, a well-known OH scavenger, has been an useful tool to analyze the behavior of heterogeneous catalysts in CWPO reactions. 2sFe/CN catalyst led to a better and efficient use of H 2 O 2 with higher hydroxyl radical yield in the presence of phenol instead of methanol, as a consequence of phenol adsorption onto the catalyst surface which minimizes the inefficient decomposition of H 2 O 2 at the same operating conditions. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate the tribological behaviour of commercially available SAE 10 mineral and rapeseed oils containing Fe particles synthesized directly in the oil phase. Design/methodology/approach – Sub-micron Fe particles (50-340 nm) were synthesized by wet chemical reduction reaction of FeSO4 by sodium borohydride in the rapeseed and mineral oils in the presence of surfactant: block copolymer (ENB 90R4) or oxyethylated alcohol (OS-20). A four-ball wear tribometer was used to investigate the tribological properties of mineral and rapeseed oil: coefficient of friction (COF), wear scar diameter and wear loss. Viscosity measurements of oil solutions and determination of synthesized Fe particles size were performed as well. Findings – The presence of Fe particles (0.1 weight per cent) in the rapeseed and mineral oils caused the little change in the COF but resulted in marked improvement of anti-wear property. The oils containing Fe particles with slightly higher viscosity are giving more friction due to viscous drag. The anti-wear enhancement is attributed to the formation of tribofilm and superior load-bearing capability of the modified oil. Both rapeseed and mineral oils irrespective of used surfactant in the presence of 0.1 weight per cent Fe particles (50-140 nm) show sufficiently improved anti-wear properties. Originality/value – The data collection about tribological behaviour of oils containing Fe particles and various additives in lubricants has a practical interest. The findings could be helpful to increase the knowledge of the behaviour of real tribological systems, where the metallic debris are generated during friction and contaminate the lubricating oil. [ABSTRACT FROM AUTHOR]

Contamination of surface water, groundwater and soil by halogenated organic compounds (HOCs) is a major problem of our society. HOCs have been used in a wide variety of applications and their presence as water contaminant is now a serious issue because of their toxicity, persistence and potential accumulation in plants and animal tissues. Transformation of HOCs by zero-valent iron represents a promising technology for environmental remediation. This mini-review outlines how iron particles are able to degrade toxic HOCs in water. It shows how the addition of one or two metals, such as palladium, copper, silver and nickel, to form bi- and tri-metallic particles can lead to a more efficient decontamination. Other ways to enhance the degradation of HOCs are the use of additives and ultrasounds. Another interesting approach is to anchor the metallic particles on various supports. Examples of the various approaches are given. [ABSTRACT FROM AUTHOR]

Magnetodielectric composites comprising dispersed metal particles as magnetic filler and organic dielectrics as a host matrix are of great importance because of both technological and fundamental interests. Surfactant-assisted high-energy ball milling in organic media is successfully used for the dispersion and surface modification of metal particles. In this paper, we have carried out structural and chemical characterization of iron particles (bulk/surface) prepared in paraffin-containing environment. The study was performed with high-resolution X-ray spectroscopic techniques using synchrotron radiation from BESSY II/HZB Berlin and DORIS/DESY Hamburg. It has been shown that high-energy ball milling leads to nanofragmentation of iron grains and formation of bare metal surface which is very active in dehydrogenation of organic molecules. The paraffin molecules are destructed with the accumulation of polycondensed aromatic structures containing covalently-bound paraffin residues on the iron surface. Under dry milling (without solvent), the organic environment molecules decompose almost completely, while under wet milling, the destruction of paraffin and perfluorononanoic acid molecules slows down significantly. An addition of perfluorononanoic acid along with n-heptane into the milling liquid results in sharp change in microwave characteristics, which may be attributed to formation of platelet-shaped particles with the surface covered with long-chain residues of paraffin and surfactant molecules. [ABSTRACT FROM AUTHOR]

Iron particles present in drinking water distribution systems (DWDSs) could cause discoloration, while organic pollutants in DWDSs, such as perfluorooctanoic acid (PFOA), could be enriched by iron particles. However, little is known about the enhanced effects of PFOA and iron particles in DWDSs. To fill in these knowledge gaps, herein, iron-PFOA (FEP) particles were generated using residual chlorine as an oxidant in drinking water conditions and then separated into different sizes (ranging from small to large: FEP-S, FEP-M ，and FEP-L). FEP-S harbored the greatest cytotoxicity among the sizes. Interestingly, our data revealed that the PFOA released from FEP particles transformed into PFOS (perfluorooctane sulfonate) upon digestion in the gastrointestinal environment (GI), and FEP-L bored the strongest transformation, showing a toxicity profile that was distinct from that of FEP-S. Furthermore, mechanistic studies revealed that FEP per se should be accountable for the conversion of PFOA to PFOS dependent on the generation of hydroxyl radicals (·OH) in GI, and that FEP-L revealed the greatest production of ·OH. Collectively, these results showed how iron particles and PFOA could result in enhanced toxicity effects in drinking water: (i) PFOA could increase the toxicity of iron particles by reducing particle size and inducing higher generation of ·OH; (ii) iron particles could induce the transformation of PFOA into more toxic PFOS through digestion. [Display omitted] • PFOA released from FEP particles may transform into PFOS through digestion. • PFOA increased toxicity of iron particle through reducing size and inducing ·OH generation. • FEP-S had the highest cytotoxicity and bioaccessibility. • FEP-L promoted the conversion of PFOA to PFOS by producing more ·OH. [ABSTRACT FROM AUTHOR]