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This study assessed concrete durability in pig farm environments, focusing on resistance to organic acid corrosion and physical abrasion. It used supplementary cementitious materials like silica fume (SF), coal fly ash (CFA), and bagasse fly ash (BFA) to improve concrete resilience. The research involved casting and testing concrete samples for compressive strength, acid corrosion resistance, abrasion resistance, and their combined effects. A custom apparatus simulated corrosion and abrasion cycles typical in pig farm flooring. Results showed that a combination of SF, CFA, and BFA significantly enhanced compressive strength, especially with extended curing. Additionally, these materials improved concrete's resistance to acid corrosion, physical abrasion, and their combined effects. The replacement of 30 wt% of cement with CFA and BFA in concrete significantly reduced mass loss due to acid corrosion to less than 10%, whereas the control mix exhibited a mass loss exceeding 24%. Additionally, concrete with 30 wt% CFA or BFA replacement exhibited a minimal combined mass loss, decreasing to less than 2.5% due to acid corrosion and physical abrasion, as opposed to the 16% observed in the control mixture.

This investigation elucidates the development of an innovative, sustainable binder derived from calcium carbide residue and silica fume, aimed at enhancing soft clay stabilization with minimal environmental impact. Various mixtures were examined, focusing on the CaO to SiO2 molar ratio (Ca/Si), which varied from 1.85 to 0.65. Comprehensive analyses of the raw materials and pastes, including chemical composition, phase evolution, and microstructure, were conducted using techniques like Energy dispersive X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Results indicate a significant impact of raw material fractions on the compressive strength and cementitious properties. The mixture with a Ca/Si of 1.55 demonstrated the highest long-term strength, attributed to increased C–S–H content. A mixture of 30 wt% calcium carbide residue and silica fume was found to improve the unconfined compressive strength of soft Bangkok clay by 84% compared to 10 wt% ordinary Portland cement, demonstrating its efficacy and potential for widespread application in green construction initiatives. This research not only promotes the recycling of industrial by-products, reducing environmental impact, but also represents a significant advancement in sustainable construction materials.

Pollution of water resources has recently increased as a result of expanded industrial activity. Recycling waste biomass into bio-adsorbent material offers a cheap, easy, and eco-friendly solution. In this study, magnetic carbon nanofibers (MCNF) with a highly porous structure were developed from magnetite-preloaded horse manure by hydrothermal treatment followed by carbonization using different ratios of iron (III) nitrate and iron oxide as magnetic precursors. The produced MCNF had a very porous structure with specific surface area of 435.31 m2/g and high carbon content. The magnetic characteristics of MCNF promoted by the presence of iron oxide species. The saturated magnetization of MCNF obtained from a 5:5 ratio of the magnetic precursors (iron (III) nitrate: iron oxide) was 2.48 emu/g. Synthesized MCNF was applied as a bio-adsorbent for methylene blue (MB) removal from aqueous solution, with results showing excellent dye adsorption of 92–99 %. MB adsorption was facilitated by pore filling, electrostatic contact, hydrogen bonding, and ion complexation. Experimental results indicated that the Freundlich isotherm and pseudo-second-order kinetic models concurred with the observed MB adsorption data, suggesting that the adsorption mechanism involved multilayered micropore interactions between magnetite and MB chemisorption. The resulting magnetic adsorbent was successfully removed from the aqueous solution by physical separation. Findings indicated that horse manure-derived MCNF could be used as an efficient bio-adsorbent to remove organic contaminants in wastewater.

Abstract The incorporation of waste materials into cementitious binders serves as a strategy to diminish waste volume and lower carbon emissions. This study presents an in-depth evaluation of calcium carbide residue and coal fly ash as alternative binders. The assessment of raw materials emphasized their chemical composition and potential for pozzolanic reactions. Based on these factors, the optimal ratio of Ca/(SiO2 + Al2O3) in the raw materials was determined to be 1.5. Therefore, this study was designed to vary the raw material composition with a CaO/(SiO2 + Al2O3) ratio ranging from 1.7 to 0.9. Upon investigating the effect of the raw material proportion on the compressive strength of pastes and mortars, the composition yielding the highest compressive strength was selected for its potential application as a stabilizer for loess soil. A mixture of calcium carbide residue and coal fly ash with a Ca/(SiO2 + Al2O3) ratio of 1.5 resulted in the highest compressive strength at long curing periods in both pastes and mortars. Mineralogical and microstructural analyses revealed several products, beyond those formed from the pozzolanic reactions, that occurred and enhanced the compressive strength of samples. The highest performing mixture of carbide residue and coal fly ash was then used to stabilize loess soil at 10–25 wt%. The unconfined compressive strength, along with mass and strength loss due to wetting and drying cycles, was also studied. It was observed that the unconfined compressive strength of the stabilized soils remained consistent after six wet-dry cycles but decreased after twelve cycles due to microcracks. The findings suggest that carefully designed mixtures based on the chemical interactions of calcium carbide residue and coal fly ash can offer a sustainable, efficient approach for soil stabilization, potentially revolutionizing construction practices.

This study presents the design of a small grid-connected power generation unit for farming systems to support the Bio-Circular-Green Economic Model (BCG) in Thailand. We focus on using the remaining agriculture waste resources to be reused according to the circular economy in the BCG model. Biogas was used as the primary fuel for an internal combustion engine, with gasoline and LPG as the immediate emergency reserves. We have integrated an engine to transmit power to a self-excited induction generator and designed a grid-connected inverter control strategy based on PQ control for the power conversion of the system by using digital signal processing. Using interface-based Internet of Things, devices can be wirelessly connected for control and logging data via a dashboard application.

Metal oxide photocatalyst is a promising wastewater treatment process due to its simplicity, high efficiency, and low cost, as well as being environmentally friendly and non-energy consuming. The perovskite structure material, SrTi1−xNbxO3 (STNO) with x = 0, 0.01, 0.03, and 0.05, was successfully synthesized by the sol-gel auto-combustion method. Samples with a pure phase and cubic perovskite structure were obtained. The Rietveld refinement results showed that the lattice parameter and unit cell density increased as the Nb-doping level increased. The particle size of the STNO decreases with increasing Nb doping content. Photoluminescence was excited at 327 nm, producing violet, green, and blue emissions, while the Nb content asserts an insignificant effect on the bandgap (Eg). The Nyquist plot and Mott-Schottky analysis were used to determine the photoelectrode performance of the STNO samples. The photocatalytic activity of STNO on the decolorization of methylene blue (MB) under UV irradiation increased with increasing Nb content and optimization at x = 0.05, corresponding to the results obtained from photoluminescence, Eg, Nyquist plot, and Mott-Schottky analyses.

This study developed a grid-connected biogas power generation system for a rural community using a 3-phase 2.2 kW squirrel-cage induction machine as the self-excited induction generator. The generator was driven by a 196 cc single-cylinder spark-ignition engine fueled by biogas. We developed a back-to-back converter that consists of a 3-phase PWM rectifier as the generator-side converter and a single-phase LCL-filtered grid-connected inverter. The generator-side converter transferred the active power to the grid-side converter and supplied the reactive power control back to the generator. The notch filter-based bus voltage control on the generator side mitigated the inter-harmonics in the generator current. The injected grid current complied with the IEEE 1547 standard because of the multi-frequency unbalanced synchronous reference frame control. The proposed system was validated with biogas produced from pig manure at a pig farm in central Thailand, which found a maximum output of 1.2 kW with a thermal system efficiency of 10.7%. The proposed system was scheduled to operate at 1.2 kW for 8 h per day with a levelized cost of 0.07 US$/kWh, 42% cheaper than the retail electricity price, and a payback period of 2.76 years. The proposed system is suitable for a farm with a minimum of 34 pigs.

The objective of this study is to investigate the resistance of concretes to organic acid corrosion and abrasive corrosion, which occurs in typical pig farms. For the concrete mixtures, cement was replaced by fly ash and silica fume with different weight percentages up to 30%. The cubic mortar and concrete specimens were prepared and tested for compressive strength and mass loss due to organic acid corrosion. The test results indicated that fly ash and silica fume mixed together significantly enhance the compressive strength of the concrete, especially at long-term curing periods. The resistance of the concrete and mortar against organic acid corrosion was greatly improved by the substitution of fly ash and silica fume. Moreover, two testing machines were developed to simulate the abrasion-corrosion attack on concrete floors in pig farms (one for organic acid corrosion tests in wet-dried conditions and the other one for an abrasion testing machine with steel brushes). The concrete slab was cast and tested with a wet-dry switching system in an organic acid solution cooperating with an abrasion test. The test results demonstrated that applying a large amount of fly ash and silica fume is not effective for increasing the resistance of the concrete against organic acid corrosion and abrasive corrosion. The concrete mixture with 5 wt% of silica fume shows the highest resistance to organic acid corrosion together with abrasive corrosion with a mass loss reduction for 7.14% compared to the reference mixture.

This research investigated the increases of the voltage profile on the Provincial Electricity Authority (PEA)’s low voltage (LV) network due to the solar photovoltaic (PV) penetration. This study proposed the solution to maintain the voltage profile within the PEA’s standard limitation by using battery energy storage system (BESS) application. The algorithm using bisection method to figure out the optimal size and location of BESS was examined and simulated in different scenarios such as summer/winter and weekend/weekday behaviors. Furthermore, the allocation of a battery in various locations was also considered. DIgSILENT power factory with DPL script and Python are the tools used to cover diverse scenario cases. The results showed that the best practice of how to implement BESS to solve the voltage rise problem was the BESS installation at the distribution transformer and the BESS installation separately at the end of each feeder near the loads. However, the optimal size of BESS installation at the distribution transformer was almost double that of installation at the end of each feeder.

Different compositions of alite calcium sulfoaluminate (ACSA) clinkers were synthesised for use as an alternative, more environmentally friendly binder than ordinary Portland cement (OPC). ACSA clinkers have a lower firing temperature than OPC clinkers, thus reducing carbon dioxide emissions during processing. Calcium fluoride (CaF2) and copper oxide (CuO) were added to the raw materials and the resulting phase formation for clinkers was compared with and without these additives. Three different compositions of ACSA clinkers as well as six different firing temperatures were tested and evaluated. Results revealed that the additives accelerated initial formation of C3S at as low as 1100 °C. The ability to process ACSA at such a low temperature enabled the coexistence of C3S - C4A3 S¯ phases in the clinker, while SO3 content greatly influenced C3S crystal formation. Unexpected CaSO4⋅2H2O loss due to evaporation in the firing process initially reduced the C4A3 S¯ phase content below the designed target. Using additional CaSO4⋅2H2O subsequently increased C4A3 S¯ content to the target level when the experiment was repeated using the optimal composition and temperature.

Abstract This study investigates the influence of Ni–Al coating thickness on the spectral selectivity and thermal performance of a parabolic trough collector (PTC). Three thicknesses of Ni–Al coating for use as solar absorber material were successfully prepared on the outer surface of a stainless steel 316L (SS) tube by flame spray. The phase, morphology, and reflectance (R) of the Ni–Al coatings were characterized using several techniques. The PTC and solar receiver tube were specially designed and constructed for observing the collector thermal performance by following ASHRAE 93-1986. Looking at the results, the actual average thicknesses of the three Ni–Al coatings turn out to be 195, 215, and 299 μm. The morphology and chemical composition of all three thicknesses are similar. The chemical composition in the cross-sectional view exhibits non-uniform distribution. The three thicknesses of the coating are composed of NiO and Al2O3 phases, which also corresponded to the results of SEM–EDX mapping. The differences in a solar absorptance (α) of the three thicknesses of Ni–Al coating are not statistically significant, with an average α value of 0.74–0.75. However, there are differences in thermal efficiency of the PTC depending on the thickness of the Ni–Al coating. Of the three samples, the thickest one (299 µm) demonstrates the highest ability to convert solar radiation into thermal energy.

Abstract The tin-pigmented aluminium oxide film (Sn–Al2O3) based solar selective absorber was successfully prepared with three different contents of tin by an anodization process. The phase and morphology of the Sn–Al2O3 were measured by X-ray diffractometer and a scanning electron microscope equipped with an energy dispersive X-ray analyser. The reflectance (R) of the coating was determined by Ultraviolet–visible-near infrared spectrophotometer in the wavelength interval of 300–2500 nm and the Fourier transform infrared spectrophotometer in the wavelength of infrared region (2500–25,000 nm). As a result, aluminium and tin phases were detected at the coating surface. The Al2O3 films were formed and compacted as a barrier on the Al substrate. The compositions of the oxide film composed of tin (Sn), aluminium (Al) and oxygen (O) elements. With increasing Sn content, the solar absorptance (α sol) gradually increased, but it has little effect on the thermal emittance (ε therm). The thermal conductivity of Sn–Al2O3 samples decreased with increasing Sn content as a result of the increasing thickness of the Sn layer at the interface leading to obstruct the free electrons and phonon contributions. The present result suggests that the increasing Sn content in the Sn–Al2O3 coating can enhance the solar selectivity properties and a good solar absorber material.

This article reports an investigation into ferrite and nanocrystalline materials for the medium-frequency transformer of a dual active bridge DC-DC converter, which plays a key role in the converter’s efficiency and power density. E65 MnZn ferrite cores and toroidal and cut nanocrystalline cores are selected for the construction of 20-kHz transformers. Transformer performance is evaluated with a 1.1-kW (42–54 V)/400 V dual active bridge DC-DC converter with single-phase shift and extended phase shift modulations. The experimental results indicate that the toroidal nanocrystalline transformer had the best performance with an efficiency range of 98.5–99.2% and power density of 12 W/cm3, whereas the cut-core nanocrystalline transformer had an efficiency range of 98.4–99.1% with a power density of 9 W/cm3, and the ferrite transformer had an efficiency range of 97.6–98.8% with a power density of 6 W/cm3. A small mismatch in the circuit parameters is found to cause saturation in the nanocrystalline toroidal core, due to its high permeability. The analytical and experimental results suggest that cut nanocrystalline cores are suitable for the dual active bridge DC-DC converter transformers with switching frequencies up to 100 kHz.

The purpose of this study is to develop a thermoelectric egg incubator (TEI) integrated with a thermal energy storage (TES) system, using electricity from photovoltaic (PV) cells in order to operate without on-grid electricity. The TEI was constructed with the same dimensions as a commercial egg incubator (CEI), which was made to the required dimensions for hatching 24 eggs per period of 21 days. The TEI was designed with 2 operating modes of heat sources: a thermoelectric (TE) module used for daytime operation and a TES containing phasechange materials (PCM) which supplied heat to the TEI for nighttime operation. The PV panels were designed to be the primary energy source for generating 360 W of electricity, which was supplied to heat sources of TEI according to the energy load for providing fertile chicken eggs (24 eggs/hatching). The incubating temperature and relative humidity (RH) inside the TEI-TES were controlled under optimum environmental conditions for hatching (36-39°C and 60-80% RH) to stimulate embryonic growth. As a result, the TEI-TES achieved and maintained an optimum incubating temperature in the range of 36.7-38.8°C and the correct RH of 66±0.2 % in the warm weather of Thailand over the incubating period of 21 days. The TEI-TES was able to maintain optimum environmental conditions for chicken-egg hatching, and its performance was comparable to that of the CEI. The working mechanisms of the TE module and TES are also discussed. The results show that the TEI-TES with PV panels as the primary energy source is suitable for use in remote areas which have no on-grid electricity supply. [ABSTRACT FROM AUTHOR]

Bismuth oxide (Bi2O3) and Bi2O3–supported Kaolin were synthesized using household microwave–assisted methods (350 W, 5 min), with catalyst characteristics analyzed. XRD patterns confirmed the monoclinic structure of Bi2O3. Incorporating 20%w/w Kaolin increased the specific surface area of Bi2O3 from 6.2879 to 16.1345 m2/g, observed in FESEM images showing a hierarchical flower-like morphology resembling French fries alongside Kaolin plates. XRF analysis identified elements in Kaolin contributing to self–doping in band structure of Bi2O3, reducing its band gap and PL intensity. Kaolin/Bi2O3 composites demonstrated enhanced photocatalytic degradation of tetracycline (TC) under visible light, attributed to Bi2O3-generated radicals and increased surface area. The composite photocatalyst can be recycled up to three times. This research not only enhances the photocatalytic activity of Bi2O3 but also increases the value of a local waste material, Kaolin clay. Such enhancements could potentially extend to other metal oxides and abundant waste materials within the country. [ABSTRACT FROM AUTHOR]

The incorporation of waste materials into cementitious binders serves as a strategy to diminish waste volume and lower carbon emissions. This study presents an in-depth evaluation of calcium carbide residue and coal fly ash as alternative binders. The assessment of raw materials emphasized their chemical composition and potential for pozzolanic reactions. Based on these factors, the optimal ratio of Ca/(SiO2 + Al2O3) in the raw materials was determined to be 1.5. Therefore, this study was designed to vary the raw material composition with a CaO/(SiO2 + Al2O3) ratio ranging from 1.7 to 0.9. Upon investigating the effect of the raw material proportion on the compressive strength of pastes and mortars, the composition yielding the highest compressive strength was selected for its potential application as a stabilizer for loess soil. A mixture of calcium carbide residue and coal fly ash with a Ca/(SiO2 + Al2O3) ratio of 1.5 resulted in the highest compressive strength at long curing periods in both pastes and mortars. Mineralogical and microstructural analyses revealed several products, beyond those formed from the pozzolanic reactions, that occurred and enhanced the compressive strength of samples. The highest performing mixture of carbide residue and coal fly ash was then used to stabilize loess soil at 10–25 wt%. The unconfined compressive strength, along with mass and strength loss due to wetting and drying cycles, was also studied. It was observed that the unconfined compressive strength of the stabilized soils remained consistent after six wet-dry cycles but decreased after twelve cycles due to microcracks. The findings suggest that carefully designed mixtures based on the chemical interactions of calcium carbide residue and coal fly ash can offer a sustainable, efficient approach for soil stabilization, potentially revolutionizing construction practices. [ABSTRACT FROM AUTHOR]

This study developed a grid-connected biogas power generation system for a rural community using a 3-phase 2.2 kW squirrel-cage induction machine as the self-excited induction generator. The generator was driven by a 196 cc single-cylinder spark-ignition engine fueled by biogas. We developed a back-to-back converter that consists of a 3-phase PWM rectifier as the generator-side converter and a single-phase LCL-filtered grid-connected inverter. The generator-side converter transferred the active power to the grid-side converter and supplied the reactive power control back to the generator. The notch filter-based bus voltage control on the generator side mitigated the inter-harmonics in the generator current. The injected grid current complied with the IEEE 1547 standard because of the multi-frequency unbalanced synchronous reference frame control. The proposed system was validated with biogas produced from pig manure at a pig farm in central Thailand, which found a maximum output of 1.2 kW with a thermal system efficiency of 10.7%. The proposed system was scheduled to operate at 1.2 kW for 8 h per day with a levelized cost of 0.07 US$/kWh, 42% cheaper than the retail electricity price, and a payback period of 2.76 years. The proposed system is suitable for a farm with a minimum of 34 pigs. [ABSTRACT FROM AUTHOR]

(1 − x)[(K0.44Na0.52Li0.04)(Nb0.84Ta0.10Sb0.06)O3] − xBi0.8Ba0.2FeO3 [(1 − x)KNLNTS-xBBF] lead-free ceramics, with different x contents, were prepared by the solid-state combustion technique. The effect of Bi0.8Ba0.2FeO3 content on the phase formation, microstructure, and electric and magnetic properties of KNLNTS ceramics were investigated. The KNLNTS ceramic exhibited co-existing orthorhombic and tetragonal phases. When x increased, the samples demonstrated an increased tetragonal phase and unit cell volume. The average grain size, density and relative density deceased when x increased up to 0.06 and then continuously increased. For x = 0, a well-saturated P–E loop was found in which the Pr and Ec values were about 21.27 μC/cm2 and 12.38 kV/cm, respectively. However, x = 0.02–0.2 exhibited a round P–E loop because the leakage current was performed. For higher x, the leakage current of the samples decreased, suggesting that the samples exhibited slim P–E loops. The KNLNTS ceramic exhibited diamagnetic behavior while the x = 0.02–0.4 samples showed ferromagnetic behavior. At room temperature, multiferroic behavior, which exhibited fair ferroelectric and ferromagnetic hysteresis loops, was obtained from the samples with x = 0.3–0.4, which means these ceramics can be applied in multifunctional devices. The maximum magnetoelectric coupling (αE) was obtained from the KNLNTS-xBBF with x = 0.4. [ABSTRACT FROM AUTHOR]

This research investigated the increases of the voltage profile on the Provincial Electricity Authority (PEA)'s low voltage (LV) network due to the solar photovoltaic (PV) penetration. This study proposed the solution to maintain the voltage profile within the PEA's standard limitation by using battery energy storage system (BESS) application. The algorithm using bisection method to figure out the optimal size and location of BESS was examined and simulated in different scenarios such as summer/winter and weekend/weekday behaviors. Furthermore, the allocation of a battery in various locations was also considered. DIgSILENT power factory with DPL script and Python are the tools used to cover diverse scenario cases. The results showed that the best practice of how to implement BESS to solve the voltage rise problem was the BESS installation at the distribution transformer and the BESS installation separately at the end of each feeder near the loads. However, the optimal size of BESS installation at the distribution transformer was almost double that of installation at the end of each feeder. [ABSTRACT FROM AUTHOR]

Metal oxide photocatalyst is a promising wastewater treatment process due to its simplicity, high efficiency, and low cost, as well as being environmentally friendly and non-energy consuming. The perovskite structure material, SrTi1−xNbxO3 (STNO) with x = 0, 0.01, 0.03, and 0.05, was successfully synthesized by the sol-gel auto-combustion method. Samples with a pure phase and cubic perovskite structure were obtained. The Rietveld refinement results showed that the lattice parameter and unit cell density increased as the Nb-doping level increased. The particle size of the STNO decreases with increasing Nb doping content. Photoluminescence was excited at 327 nm, producing violet, green, and blue emissions, while the Nb content asserts an insignificant effect on the bandgap (Eg). The Nyquist plot and Mott-Schottky analysis were used to determine the photoelectrode performance of the STNO samples. The photocatalytic activity of STNO on the decolorization of methylene blue (MB) under UV irradiation increased with increasing Nb content and optimization at x = 0.05, corresponding to the results obtained from photoluminescence, Eg, Nyquist plot, and Mott-Schottky analyses. [ABSTRACT FROM AUTHOR]

The effect of the firing conditions on the phase formation, microstructure, and electrical properties of (K0.5Na0.5)(Nb0.7Ta0.3)O3 (KNNT) ceramics synthesized by the solid-state combustion technique using glycine as fuel has been investigated. All samples were calcined at 600°C to 800°C for 2 h and sintered at 1150°C to 1190°C for 2 h to 5 h. Pure KNNT powders were produced after calcination at 600°C for 2 h. The average particle size increased when the calcination temperature was increased. The KNNT powder calcined at 600°C for 2 h showed rather square morphology with average particle size of ∼ 160 nm. The x-ray diffraction (XRD) analysis results for the ceramics revealed the presence of orthorhombic (O) and tetragonal (T) phases in all samples. When sintering at 1150°C for 4 h, the O:T ratio was 50:50, as verified by the Rietveld refinement technique. The average grain size, density values, and dielectric properties tended to increase when the dwell time was increased from 2 h to 4 h, but then degraded. The KNNT ceramic produced at the optimum firing condition (1150°C for 4 h) showed good crystalline morphology, the highest density (ρ = 5.28 g/cm3), the highest dielectric constant (εC = 5002), and good ferroelectric behavior (Pr = 18.50 μC/cm2 and Ec = 9.04 kV/cm). [ABSTRACT FROM AUTHOR]

Lead-free 0.94Bi0.50Na0.50TiO3–0.06Ba0.85Ca0.15Ti0.90Zr0.10O3–xmol%Bi2FeCrO6 ceramics, with x = 0–0.021 (BNT–BCTZ–xBFCO), were calcined at 650 °C for 2 h and sintered at 1150 °C for 2 h using the solid-state combustion technique. The effect of BFCO content (x) on the phase formation, microstructure, electrical and magnetic properties was studied. The sintered pellets exhibited a pure perovskite phase with the coexistence of rhombohedral (R3c) and tetragonal (P4bm) phases in all the studied compositions. The percentage of R3c increased as x increased from 0 to 0.013, before decreasing, as obtained from the Rietveld refinement analysis (Fullprof). A morphotropic phase boundary of BNT–BCTZ–xBFCO ceramics was observed at x = 0.013, and the ratio between the rhombohedral and tetragonal phases of this composition was 51.0:49.0. The scanning electron microscopy analysis showed polyhedral-shaped grains whose average size increased with increase in the BFCO content (x). The appropriate amount of BFCO doped into BNT–BCTZ ceramics enhanced the electrical, ferroelectric and piezoelectric properties. At optimum doping (x = 0.013), the sample exhibited the highest relative density (98.2%), a high dielectric constant (εR = 1572 and εm = 5137), maximum remanent polarization (Pr = 42.41 µC/cm2), low coercive field (Ec = 33.57 kV/cm), maximum piezoelectric coefficient (d33 = 241 pC/N) and the highest normalized strain ( d 33 ∗ = Smax/Emax = 765 pm/V). These improvements to BNT–BCTZ make the ceramic a potential candidate for use in capacitors, sensors and actuators. The magnetic properties also changed with different BFCO content (x). The sample with x = 0 showed diamagnetic behavior, while the samples with 0.003 ≤ x ≤ 0.021 exhibited a paramagnetic behavior with higher magnetization at higher BFCO content. [ABSTRACT FROM AUTHOR]

The tin-pigmented aluminium oxide film (Sn-AlO) based solar selective absorber was successfully prepared with three different contents of tin by an anodization process. The phase and morphology of the Sn-AlO were measured by X-ray diffractometer and a scanning electron microscope equipped with an energy dispersive X-ray analyser. The reflectance ( R) of the coating was determined by Ultraviolet-visible-near infrared spectrophotometer in the wavelength interval of 300-2500 nm and the Fourier transform infrared spectrophotometer in the wavelength of infrared region (2500-25,000 nm). As a result, aluminium and tin phases were detected at the coating surface. The AlO films were formed and compacted as a barrier on the Al substrate. The compositions of the oxide film composed of tin (Sn), aluminium (Al) and oxygen (O) elements. With increasing Sn content, the solar absorptance ( α) gradually increased, but it has little effect on the thermal emittance ( ε). The thermal conductivity of Sn-AlO samples decreased with increasing Sn content as a result of the increasing thickness of the Sn layer at the interface leading to obstruct the free electrons and phonon contributions. The present result suggests that the increasing Sn content in the Sn-AlO coating can enhance the solar selectivity properties and a good solar absorber material. [ABSTRACT FROM AUTHOR]

This article reports an investigation into ferrite and nanocrystalline materials for the medium-frequency transformer of a dual active bridge DC-DC converter, which plays a key role in the converter's efficiency and power density. E65 MnZn ferrite cores and toroidal and cut nanocrystalline cores are selected for the construction of 20-kHz transformers. Transformer performance is evaluated with a 1.1-kW (42–54 V)/400 V dual active bridge DC-DC converter with single-phase shift and extended phase shift modulations. The experimental results indicate that the toroidal nanocrystalline transformer had the best performance with an efficiency range of 98.5–99.2% and power density of 12 W/cm3, whereas the cut-core nanocrystalline transformer had an efficiency range of 98.4–99.1% with a power density of 9 W/cm3, and the ferrite transformer had an efficiency range of 97.6–98.8% with a power density of 6 W/cm3. A small mismatch in the circuit parameters is found to cause saturation in the nanocrystalline toroidal core, due to its high permeability. The analytical and experimental results suggest that cut nanocrystalline cores are suitable for the dual active bridge DC-DC converter transformers with switching frequencies up to 100 kHz. [ABSTRACT FROM AUTHOR]

This study investigates the influence of Ni-Al coating thickness on the spectral selectivity and thermal performance of a parabolic trough collector (PTC). Three thicknesses of Ni-Al coating for use as solar absorber material were successfully prepared on the outer surface of a stainless steel 316L (SS) tube by flame spray. The phase, morphology, and reflectance (R) of the Ni-Al coatings were characterized using several techniques. The PTC and solar receiver tube were specially designed and constructed for observing the collector thermal performance by following ASHRAE 93-1986. Looking at the results, the actual average thicknesses of the three Ni-Al coatings turn out to be 195, 215, and 299 μm. The morphology and chemical composition of all three thicknesses are similar. The chemical composition in the cross-sectional view exhibits non-uniform distribution. The three thicknesses of the coating are composed of NiO and Al2O3 phases, which also corresponded to the results of SEM-EDX mapping. The differences in a solar absorptance (α) of the three thicknesses of Ni-Al coating are not statistically significant, with an average α value of 0.74-0.75. However, there are differences in thermal efficiency of the PTC depending on the thickness of the Ni-Al coating. Of the three samples, the thickest one (299 µm) demonstrates the highest ability to convert solar radiation into thermal energy. [ABSTRACT FROM AUTHOR]