Scanning Electron Microscopy Equipped With Energy Dispersive Spectroscopy Research Articles

Synthesis of geopolymer using glass fiber powder from retired wind blades: A new attempt to recycle solid waste in wind power industries

This study explores the potential of recycling and utilizing discarded wind turbine blades. It proposes a new method that upcycles the glass fiber powder (GFP) in these blades into geopolymer gel, offering a new solution for the recycling and treatment of retired wind blades. Analyses of the X-ray diffraction (XRD) pattern of the GFP raw material and its dissolution in concentrated alkali indicate a large content of vitreous and active silica-aluminum, suggesting its suitability for producing geopolymers through alkali activation. The effects of the alkali activator modulus (Ms), alkali-binder ratio (N/B), and water-binder ratio (W/B), raw material particle size, and initial curing temperature on the compressive strength of the specimens were comprehensively and systematically investigated. The reaction behavior, chemical structure, and microstructure of GFP-synthesized geopolymers were characterized by selective dissolution, microcalorimetry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). The results showed that gels were formed by the geopolymerization reaction between the GFP and alkali activator. The compressive strength of the specimens increased first and then decreased with increasing alkali activator Ms and N/B. However, increasing W/B led to a decrease in strength. Appropriately small particle sizes of the raw material and moderately increasing the initial curing temperature are beneficial to strengthen the compressive strength. The optimal 28 d compressive strength of 43.43 MPa was achieved with an activator Ms of 1.4, N/B of 10%, W/B of 0.33, GFP with a D90 of 170 mesh, and an initial 24 h curing temperature of 60 °C. The results of this study can promote the utilization of waste wind blades in the production of sustainable building materials.

DEVELOPMENT OF MULLITE- CARBON REFRACTORY CERAMIC COMPOSITE FROM LOCALLY SOURCED MATERIALS

In the pursuit of developing a mullite- carbon refractory ceramic composite with optimum physical and mechanical properties modified with additives, experimental studies were carried out using local materials from Nigeria's south-south and south-west regions. Kaolin clay was crushed to 2 mm and ball-milled into powder. Ground kaolin was homogeneously blended with graphite using a ball mill and sieved through a 300μm electric sieve. The homogeneous mix was combined with predetermined Magnesium Oxide proportions, compacted, and fired at 1300 °C, 1400 °C, and 1500 °C. Extensive tests followed, including X-ray diffraction (XRD) for phase analysis, ultra-high- resolution field emission scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS) for microstructural morphology, and assessments of mechanical and physical properties. Findings indicated that additive inclusion spurred mullite phase development between 1300°C and 1500°C, enhancing their physico- mechanical properties. Among the samples, Sample R composed of 15% MgO, 65% kaolin, and 20% graphite, fired at 1500°C, displayed optimal physico-mechanical properties (95.8%) and favorable mullite formation (46.0%) was achieved.

Preparation and Hydration Properties of Steel Slag-Based Composite Cementitious Materials with High Strength.

Steel slag (SS) has been largely discharged but little utilized, causing an environmental problem in China. In this paper, SS-based composite cementitious materials with high strength were prepared by the high volume of SS (≥40%), granulated blast-furnace slag (GBFS), fly ash (FA), flue gas desulfurization gypsum (FGDG) and cement to promote the effective utilization of SS. The hydration and hardening properties were studied through setting time, compressive strength, length change, isothermal calorimetry (IC), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS) tests. The results show that SS-based composite cementitious material exhibited a lower hydration heat release, an appropriate setting time, and volume stability. The SS cementitious material with 40% SS could obtain high strength of over 65 MPa at 28 days and 80 MPa at 90 days. The strength value of > 60 MPa is present in the binder, with 50% SS at 56 days. GBFS promotes hydration reactions and the formation of AFt and C-(A)-S-H gel, thus enhancing compressive strength. FA has a beneficial effect on later strength. The small and fine pore structures contribute to the development of strength. The main hydration products of SS composite cementitious materials are C-(A)-S-H gel, and ettringite (AFt), with less Ca(OH)2. The C-(A)-S-H gel with a lower Ca/Si ratio and a higher Al/Ca ratio in cementitious material, promotes mechanical properties.

Tannic Acid Coatings to Control the Degradation of AZ91 Mg Alloy Porous Structures

Porous structures of magnesium alloys are promising bioimplants due to their biocompatibility and biodegradability. However, their degradation is too rapid compared to tissue regeneration and does not allow a progressive metal substitution with the new biological tissue. Moreover, rapid degradation is connected to an accelerated ion release, hydrogen development, and pH increase, which are often causes of tissue inflammation. In the present research, a natural organic coating based on tannic acid was obtained on Mg AZ91 porous structures without toxic reagents. Mg AZ91 porous structures have been prepared by the innovative combination of 3D printing and investment casting, allowing fully customized objects to be produced. Bare and coated samples were characterized using scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), fluorescence microscopy, Fourier transformed infrared spectroscopy (FTIR), tape adhesion test, Folin–Ciocalteu, and degradation tests. Different parameters (solvent, dipping time) were compared to optimize the coating process. The optimized coating was uniform on the outer and inner surfaces of the porous structures and significantly reduced the material degradation rate and pH increase in physiological conditions (phosphate-buffered saline—PBS).

Synergistic effect of Black cumin extract and zinc cations on the mild steel corrosion resistance improvement in NaCl solution; Surface and electrochemical explorations

Corrosion inhibitors are used to enhance the anti-corrosion properties of mild steel in corrosive environments. In this study, for the first time, a hybrid corrosion inhibitor based on Black cumin extract (BCE) and zinc cations was employed to mitigate the mild steel dissolution rate in NaCl media. The inhibitive film fabricated on the metal surface in the presence of BCE was characterized by scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, Grazing Incidence X-ray Diffraction (GIXRD), and UV–vis tests. Also, the electrochemical impedance spectroscopy (EIS) and Potentiodynamic polarization tests were engaged in 3.5 wt%. NaCl solution to study the protection performance of the metal in the presence of inhibitors. Due to the fabrication of inhibitive film, the anti-corrosion properties of the mild steel are significantly enhanced in the presence of organic/inorganic corrosion inhibitors. The creation of the inhibitive film in the presence of hybrid corrosion inhibitors was proved through SEM analysis and electrochemical testing. Electrochemical tests proved a synergistic effect between the selected inhibitors. The inhibitor efficiency for hybrid corrosion inhibitor was calculated at about 95 %, and 90 % in EIS and polarization tests, respectively. FT-IR, Raman, and XRD tests' outcomes proved the complex inhibitors' film formation over the metal substrate.

Nanoindentation mechanical properties of U-5.5 wt%Nb treated by continuous electron beam surface remelting

Understanding the microstructure evolution and mechanical property of the electron beam based process for remelting is important for manufacturing, repair, and surface modification. In this work, based on the nanoindentation theory, the sub-microscale mechanical properties of U-5.5 wt%Nb alloy (U-5.5 Nb) remelted by continuous electron beam scanning process (CEBSP) were systematically studied for the first time by the means of nanoindentation. Additionally, optical microscopy (OM) and scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS) were used to evaluate the evolution of the microstructure and the element redistribution. The results revealed that the microstructure and/or the microsegregation of both niobium and carbon had a significant influence on the local mechanical properties of the CEBSP treated U-5.5 Nb. A surface strengthened layer with the average elastic modulus and hardness of 68.4 ± 15.1 GPa and 4.8 ± 1.2 GPa was obtained by CEBSP, which were much higher than the corresponding values of the untreated alloy (i.e. 47.2 ± 2.8 GPa and 2.6 ± 0.3 GPa for the substrate), suggesting a 15.6–44.5% increase in the anti-wear performance. Additionally, except for plasticity, the mechanical properties including yield strength, creep resistance, and fracture toughness increased by CEBSP. Finally, based on the experimental analysis results, the relationship between microstructure and mechanical property (especially the hardness) is discussed in detail, and a model is proposed to explain the plastic deformation mechanism during nanoindentation tests.

Photocatalytic activity under visible light illumination of organic dyes over g-C3N4/MgAl2O4 nanocomposite

Using a grinding method, nanocomposites of graphitic carbon nitride (g-C3N4) and magnesium aluminate (MgAl2O4) spinel were successfully synthesized for the photocatalytic degradation of methylene blue (MB) and methyl orange (MO). Variously formulated g-C3N4/MgAl2O4 nanocomposites were characterized by thermal gravimetric analysis (TGA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS), transmission electron microscopy (TEM) and surface area and micropore analysis (BET surface area). The g-C3N4 powder exhibited a nanosheet structure whereas the MgAl2O4 spinel comprised agglomerated nanoparticles. The optical properties of the g-C3N4/MgAl2O4 nanocomposites were investigated by diffuse reflectance spectroscopy (DRS). As the g-C3N4 loading content increased from 0 to 30%, the optical band gap energy of the nanocomposite decreased from 3.84 to 2.86 eV, the specific surface area decreased from 153.78 to 114.45 m2/g, and the porosity decreased from 0.447 to 0.347 cm3/g. A 20%g-C3N4/MgAl2O4 nanocomposite proved to be the most effective photocatalyst and degraded MB faster and more completely than MO. The degradation rates of both MO (0.0107 min−1) and MB (0.0386 min−1) in a mixed MO-MB system were greater than the degradation rates in their single systems. The key factor that improved the photocatalytic degradation of MO was the synergistic effect whereas the synergistic effect and photosensitization were the key factors that enhanced the photocatalytic degradation of MB. The g-C3N4/MgAl2O4 nanocomposite is suitable for the photocatalytic degradation of mixed dyes because its point of zero charge is neutral and it is stable and recyclable.

Highly dense (Mn,Co)3O4 spinel protective coating derived from Mn–Co metal precursors for SOFC interconnect applications

The major degradation issues of solid oxide fuel cells (SOFC) are associated with the Cr2O3 scale growth and Cr diffusion of the Cr-based ferritic stainless steel (FSS) interconnects. Although (Mn,Co)3O4 has been proved as a suitable material for protecting FSS interconnects, the porous structure of the coatings prepared with the pre-synthesized spinel weakens the protective capability of the coatings. In this paper, the widely-used pre-synthesized spinel is replaced with metal precursors (Mn and Co powders). Due to the low melting point (≤1290 °C) and the volume expansion during oxidation, the metal precursors, can be effectively sintered at 900 °C in a reducing atmosphere and form dense, well-protective coatings at 850 °C in the air. The samples are characterized with X-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and a 4-probe area-specific resistance (ASR) test. Compared with the coatings derived from pre-synthesized spinel, the metal-derived coatings present denser structures with better electrical conductivity (ASR = 5.76 mΩ cm2). The weight gain and ASR measurement results indicate that the metal-derived coatings significantly mitigate the increase of weight gain and ASR by inhibiting scale formation and growth, showing better protective capability for SOFC applications.

Colloidal metal transport in soils developing on historic coal mine spoil

Chemical weathering of pyrite via oxidative dissolution is well-known for generating Fe(III)-bearing colloids at acid mine drainage (AMD) sites; however, the potential for physical weathering of pyrite-bearing materials and subsequent release and transport of colloidal pyrite and associated trace metals has not been studied. Here, we monitored the colloidal metal transport in soil developing on abandoned coal mine spoil with a history of AMD generation to systematically study the contribution of colloids to base and trace metal transport and determine the elemental and mineralogical composition of colloids. We collected soil pore water using lysimeters with a pore size of approximately 1.3 μm and centrifugation was used to separate the colloids from aqueous fractions. Metal concentrations of Na, Ca, Mg, K, Si, Al, Mn, Fe, Cu, and Zn were analyzed. Our results show only 14% of the total Al and Cu were present in colloidal fractions whereas 23%, 43%, and 54% of Fe, Mn, and Zn were transported in the colloidal phase, respectively. In contrast, all base metals were primarily present in the aqueous concentration with a small fraction (<10%) present in the colloidal phase. The colloidal fractions of the base metals were inferred to be associated with the concentration of clay colloids. The release of colloids exhibited possible sensitivity toward weather conditions such as alternating high temperatures and rainfall during summer (May–July) compared to fall (August–November). The morphology, elemental, and mineral composition of colloids were determined by a scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). Colloids were dominated by phyllosilicates (biotite, muscovite, and kaolinite) with minor quartz and feldspars. Other minerals phases identified in colloidal fractions were hematite, goethite, arsenopyrite, and chalcopyrite. Colloids consisting of Fe, S, and O with structures resembling framboidal pyrite were identified, which is consistent with the non-silicates minerals identified by XRD. Our study suggests that the physical weathering of pyrite in the mine spoil can generate colloidal pyrite, which is mobilized and transported by soil pore water. Our results also indicate that these pyritic colloids are associated with toxic trace metals including Cu, Mn, and Zn. Colloid mobilization is also impacted by changes in temperature and precipitation, where clay mobilization afer rain events is favored. Further, sudden spikes in aqueous and/or colloidal concentrations may be the result of local heterogeneity within soils developing on mine spoil, indicating that further field-based work is necessary to better characterize pore-scale processes that control aqueous and colloid transport at similar sites to have a better understanding of potential contaminant transport from mine spoil systems.

Effects of Process-Induced Supersaturation on the Oxidationbehavior of Alloy718 Fabricated By Additive Manufacturing Technologies

Alloy718 is widely used in gas turbines and related aerospace applications due to its excellent mechanical properties and structural stability at elevated temperatures. Alloy718 is a precipitation-strengthened superalloy which is generally manufactured through casting, forging, and heat treatment. Over the past decade a variety of additive manufacturing (AM) technologies involving laser and electron beam have become increasingly attractive fabrication methods due to their several advantages over conventional manufacturing methods, such as a large degree of design flexibility, and reductions in the lead time and investment cost. However, the selective laser melting process (rapid heating and cooling) will make matrix gets supersaturated in alloying elements, in particular Nb, Ti and Al, which have significant effects on the formation of the strengthening phases in austenite matrix, e.g., γ′′ (Ni3Nb,), γ′ (Ni3Al,Ti) phases.Up to now, the specific influences of supersaturation on the oxidation behavior of the scales in a Cr-forming Ni-based alloy have not been dealt with in depth.In this study, the oxidation behavior of Alloy718 specimens produced by selective laser melting (SLM) and electron beam melting (EBM) process were comparatively examined. A slower cooling rate and a preheating process in the EBM process contribute relatively lower degree of saturation in \U0001d6fe matrix. On the other hand, the high thermal gradient and rapid solidification rate in SLM process lead to supersaturation in \U0001d6fe matrix. All alloys were studied in two versions to compare the order of supersaturation: “As-received” and heat treated (HT). The heat treatment procedure was carried out at 980 °C for 1 h/air cooling to room temperature and a two-step aging treatment consisting of 718 °C for 8 h/furnace cooling to 621 °C and holding at 621 °C for 10 h before AC to room temperature. The oxidation kinetics as well as the surface morphology of the oxide scales were characterized by means of weight gain measurements, scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), electron probe microanalysis (EPMA), X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis techniques.The experimental results indicated that the oxidation performance of as-received SLM samples were better than those of as-received EBM samples due to the formation of thinner Cr2O3 scale without spallation. In addition, the morphology of their chromia scale was different. Coarse and columnar chromia grains developed on SLM samples, whereas the chromia scale of EBM samples consisted of extremely fine grains. After heat treatment process, the oxidation kinetics of heat-treated samples were increased compare to as-received samples. Moreover, the fine-grained chromia scale which is similar to that formed on EBM samples was formed on heat-treated SLM samples. The mentioned results indicate that the degree of supersaturation in the matrix did affect the morphology of chromia scale resulting in the oxidation kinetics.

The mechanical and chemical stability of the interfaces in bioactive materials: The substrate-bioactive surface layer and hydroxyapatite-bioactive surface layer interfaces.

Bioactive materials should maintain their properties during implantation and for long time in contact with physiological fluids and tissues. In the present research, five different bioactive materials (a bioactive glass and four different chemically treated bioactive titanium surfaces) have been studied and compared in terms of mechanical stability of the surface bioactive layer-substrate interface, their long term bioactivity, the type of hydroxyapatite matured and the stability of the hydroxyapatite-surface bioactive layer interface. Numerous physical and chemical analyses (such as Raman spectroscopy, macro and micro scratch tests, soaking in SBF, Field Emission Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS), zeta potential measurements and Fourier Transformed Infra-Red spectroscopy (FTIR) with chemical imaging) were used. Scratch measurements evidenced differences among the metallic surfaces concerning the mechanical stability of the surface bioactive layer-substrate interface. All the surfaces, despite of different kinetics of bioactivity, are covered by a bone like carbonate-hydroxyapatite with B-type substitution after 28days of soaking in SBF. However, the stability of the apatite layer is not the same for all the materials: dissolution occurs at pH around 4 (close to inflammation condition) in a more pronounced way for the surfaces with faster bioactivity together with detachment of the surface bioactive layer. A protocol of characterization is here suggested to predict the implant-bone interface stability.

Light-Enhanced Adsorptive Desulfurization of Dibenzothiophene Using Supported TiO&lt;sub&gt;2&lt;/sub&gt;-ZrO&lt;sub&gt;2&lt;/sub&gt;

Combustion of diesel fuel containing sulfur compounds emits SOx into atmosphere causing acid rain and respiratory illness in human. Dibenzothiophene (DBT) is one of the most difficult sulfur compounds in diesel to be removed by hydrodesulfurization (HDS). To produce ultra-low sulfur diesel (&lt;15 ppmw-S), severe operating condition is required. As a result, production cost is increase. In this work, we investigated an alternative method for sulfur removal called Light-enhanced Adsorptive Desulfurization or L-ADS using supported TiO2-ZrO2. The TiO2-ZrO2 was loaded on commercial γ-Al2O3, fumed silica (FS), silica gel (SG) and zeolite (Z30) by wet-impregnation method. Impact of these supports on DBT removal were focused. Characteristic of the supported TiO2-ZrO2 was analyzed by N2 adsorption-desorption, scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The presence of TiO2-ZrO2 greatly enhanced DBT removal compared to TiO2 and ZrO2. SG promoted DBT removal by facilitating the adsorption of dibenzothiophene sulfone (DBTO2), a product of DBT photocatalytic oxidation. Using TiO2-ZrO2/SG, 86% of sulfur was removed from 50 ppmw-S DBT/C16 within 4 h.

Twenty Years after the Nakhodka Oil Spill Accident in the Sea of Japan, How Has Contamination Changed?

The Nakhodka, a Russian tanker loaded with 19,000 kL of C-type heavy oil, was broken up into sections and submerged off Oki Island, Shimane Prefecture, Japan on 2 January 1997. The bow, after drifting for four days, was wrecked off Anto, Sakai City (Mikuni), Fukui Prefecture, threatening the environment throughout the various shores of Ishikawa Prefecture. The accident, caused by a heavy oil spill of 6200 kL, created serious environmental problems along the shores of Hokuriku District. We report the characterization of C-type heavy oil 20 years after the accident at the Atake seashore, Wajima City, Ishikawa Prefecture, in the Sea of Japan, based on observations in the field on 18 January 2017. We studied the microstructure, mineralogy, chemical composition, and radioactivity associated with microorganisms in the soils, and buried fishing nets and ropes that were contaminated with C-type heavy oil from this spill. The analyses used a combination of micro techniques, analytical data based on a CHN analyzer, X-ray powder diffraction (XRD), and two kinds of scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). Hydrocarbon-degrading bacteria, paraffin wax, cristobalite, graphite, calcite, halite, and biotite from the Nakhodka oil spill were recognized on the surface of ropes and in the soil of the polluted seashores after 20 years. The chemical compositions indicated that high concentrations of C, O, Na, Al, Si, P, S, Ca, Fe, Cl, Sr, and Pb were predominantly indigenous to the Nakhodka oil spill. In the XRD analysis of the oil-contaminated soils on the rope at the Atake seashore indicated paraffin wax, graphite, sulfate, calcite and halite refractions with clay minerals, after 20 years. To date, no report has described the results of electron microscopy observations, such as Micrococcus bacillus and filamentous fungi, found in oil-contaminated soils after 20 years. In this research, such observations are introduced as “bioremediation” by hydrocarbon-degrading bacteria, graphite, and paraffin wax. On 18 January 2017, the reflection of graphite, paraffin wax, sulfur, calcite, and halite with clay minerals confirmed the occurrence of bioremediation. Many kinds of hydrocarbon-degrading microorganisms—such as filamentous fungi—were found in oil-contaminated soils after 20 years. We have used SEM-EDS to show semi-permanent bioremediation and biomineralization processes after 20 years.

Effect of the Addition of Molybdenum on the Structure and Corrosion Resistance of Zinc–Iron Plating

Zn–Ni plating is indispensable in various industries because of its high corrosion resistance. However, Ni has been reported to trigger allergies; thus, an alternative Ni-free plating is desired. Zn–Fe plating is considered to be a promising candidate, albeit its corrosion resistance still needs to be improved. The corrosion resistance of Zn–Fe plating is expected to increase by the addition of Mo as the third alloying element as it is more noble than Zn and Fe. In this study, Zn–Fe–Mo plating with a corrosion resistance nearly equivalent to that of the Zn–Ni plating was fabricated. Zn–Fe–Mo plating was electrically deposited from continuously-agitated plating baths prepared by mixing ZnSO4, FeSO4, Na2MoO4, Na3C6H5O7, and Na2SO4 using Fe or Ni plates as the substrate. The surface morphology, composition, crystal phase, and electronic state of Mo of the platings were investigated by scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion performance was evaluated by Tafel extrapolation method. Formation of plating comprising a Mo containing alloy phase was found to be crucial for improving corrosion resistance. The Zn–Fe–Mo plating demonstrates promise for replacing anti-corrosion Zn–Ni platings.

Electron Microscopy Observation of Biomineralization within Wood Tissues of Kurogaki

Interactions between minerals and microorganisms play a crucial role in living wood tissues. However, living wood tissues have never been studied in the field. Fortunately, we found several kurogaki (black persimmon; Diospyros kaki) trees at Tawara in Kanazawa, Ishikawa, Japan. Here, we report the characterization of kurogaki based on scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM), associated with inductively coupled plasma-mass spectrometry (ICP-MS) analyses, X-ray fluorescence analyses (XRF) and X-ray powder diffraction (XRD) analyses. This study aims to illustrate the ability of various microorganisms associated with biominerals within wood tissues of kurogaki, as shown by SEM-EDS elemental content maps and TEM images. Kurogaki grows very slowly and has extremely hard wood, known for its striking black and beige coloration, referred to as a “peacock pattern”. However, the scientific data for kurogaki are very limited. The black “peacock pattern” of the wood mainly comprises cellulose and high levels of crystal cristobalite. As per the XRD results, the black taproot contains mineralized 7 Å clays (kaolinite), cellulose, apatite and cristobalite associated with many microorganisms. The chemical compositions of the black and beige portions of the black persimmon tree were obtained by ICP-MS analyses. Particular elements such as abundant Ca, Mg, K, P, Mn, Ba, S, Cl, Fe, Na, and Al were concentrated in the black region, associated with Pb and Sr elements. SEM-EDS semi-qualitative analyses of kurogaki indicated an abundance of P and Ca in microorganisms in the black region, associated with Pb, Sr, S, Mn, and Mg elements. On the other hand, XRF and XRD mineralogical data showed that fresh andesite, weathered andesite, and the soils around the roots of kurogaki correlate with biomineralization of the black region in kurogaki roots, showing clay minerals (kaolinite) and cristobalite formation. In conclusion, we describe how the biominerals in the black region in the cellulose within wood tissues grow chemically and biologically in the sap under the conditions associated with the beige portions of the taproot. This can explain why the crystals produce the “peacock pattern” in the kurogaki formed during the year. We conclude that kurogaki microbiota are from bacteria in the andesitic weathered soil environment, which produce silicification. In other words, the patterned portions of kurogaki consist of silicified wood.

Oxidation Behavior of a Disk Powder Metallurgy Superalloy

Oxidation behaviors of a spray-forming disk superalloy LSHR were investigated in the temperature range of 750-900°C. The composition and morphology of oxidation scales were investigated by X-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and electron probe microanalysis (EPMA). Oxidation kinetics was studied by the means of isothermal oxidation testing in air and weight gain measurement. The oxide scales were composed of Cr2O3, TiO2, Al2O3 and a small amount of NiCr2O4. The experiment results showed that oxidation kinetics and oxide layers followed a square power law as time extended from 750 to 900°C. With the oxidation temperature increasing, external scale thickness, and internal oxidation zone increased. The oxidation behavior was controlled by the diffusion of oxygen, chromium, titanium, and aluminum ions, as chromium, titanium, and aluminum ions diffused outward and oxygen diffused inward. Based on the standard HB5258-2000 spray-forming LSHR exhibited an excellent oxidation resistance in the whole test temperature range.

Experimental and theoretical studies on mild steel corrosion inhibition by the grieseofulvin in 1 M HCl

The inhibition effect of grieseofulvin against the mild steel corrosion in 1 M HCl solution has been investigated by potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS) and quantum chemical methods. It was found thatgrieseofulvin acts as a good mild steel corrosion inhibitor in the acid solution at temperature ranging from 298-328 K. The potentiodynamic polarization study reveals that grieseofulvin acts as mixed type inhibitor. The adsorption of grieseofulvin on mild steel follows the Langmuir adsorption isotherm. Scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS) studies established that grieseofulvin formed a protective layer on the surface of mild steel.

Experimental Study of the Interaction of Solanum Tuberosum Fluid as Additive in Electrodeposition Bath in the Presence of Zn-Tio2 on Mild Steel

Enhancing mild steel properties is necessary to meet global competiveness and performance during application. In this study, we report the effect of Solanum tuberosum as additive to Zn-TiO2 sulphate bath coating by electrodeposition method on low carbon steel. The interfacial and structural characteristics of the produced coating were examined by means of scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS). The corrosion resistance properties of the deposited coatings were assessed in 3.65% NaCl using linear polarization method and characterized by optical microscope (OPM). Diamond based microhardness tester was used to measure hardness of the composites. From the results, it is evident that Zn-TiO2-solanum coating resulted in improved performance as compared to Zn-TiO2 coating; both in hardness properties and corrosion resistance properties propagation as a result of its embedded structural build up.

Oxidation and electrical behavior of CuFe2O4 spinel coated Crofer 22 APU stainless steel for SOFC interconnect application

In an attempt, CuFe2O4 spinel coating was investigated with the purpose of increasing the performance of Crofer 22 APU ferritic stainless steel as a potential SOFC interconnect material. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS) and 4-probe area specific resistance (ASR) tests. CuFe2O4 spinel layers were deposited via screen-printing method on the bare and pre-oxidized samples. Good bonding between the coating and the substrate was achieved by the reactive sintering process of the reduced coating. Long term oxidation experiments and ASR measurements are investigated. The results indicated that the spinel protection layers not only significantly decreased the ASR, but also inhibited the subscale growth by acting as a barrier to the inward diffusion of oxygen. An ASR of 13.8 and 26.7mΩ⋅cm2at 800°C after 400h oxidation were achieved for the bare and pre-oxidized CuFe2O4 spinel coated samples, respectively, which were much lower than that of the bare substrate (48mΩ⋅cm2) at the same temperature. The ASR of 14.3mΩ⋅cm2was reached after 600h of exposure at 800 for the coated sample. The high electrical conductivity of CuFe2O4 spinel and its doping by Mn, inhibition of the resistive Cr2O3 oxide scale growth, and good adherent between the coating and substrate are supposed to be responsible for the substantial electrical conductivity improvement.

Mesoporous silica nanoparticles enhance seedling growth and photosynthesis in wheat and lupin

The application of mesoporous silica nanoparticles (MSNs) as a smart delivery system to agricultural crops is gaining attention but the release of nanoparticles into the environment may pose a potential threat to biological systems. We investigated the effects of MSNs on the growth and development of wheat and lupin plants grown under controlled conditions. We report a dramatic increase in the growth of wheat and lupin plants exposed to MSNs. We also found that, in leaves, MSNs localised to chloroplasts and that photosynthetic activity was significantly increased. In addition, absorption and cellular distribution of MSNs by the two plant species following root uptake were observed using scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). Following uptake of MSNs at 500 and 1000 mg L−1, there was enhancement of seed germination, increased plant biomass, total protein and chlorophyll content. Treatment of both species with MSNs at the highest concentration (2000 mg L−1) did not result in oxidative stress or cell membrane damage. These findings show that MSNs can be used as novel delivery systems in plants and that over the range of concentrations tested, MSNs do not have any negative impacts on plant growth or development.