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This paper aims to better design the resonant tank parameters for LLC resonant converter. And, it is found that under heavy load, the voltage gain is affected by junction capacitors of the primary side switching and the parasitic parameters of the secondary side diodes converted to the primary side, which will cause the voltage gain decreased when the switching frequency decreased.

This paper proposes an optimization parameters design method to solve this problem, which was based on impedance model considering the parasitic parameters of switching devices and diodes.

The effectiveness of the proposed method is verified by impedance Bode plots and experimental results.

From the perspective of impedance modeling, this paper finds the reasons for the insufficient voltage regulation capability of LLC resonant converters under heavy load and finds solutions through analysis.

This study aims to solve the problem that under light-load conditions, the output voltage regulation capability is lost due to the fact that the voltage gain of the LLC resonant converter does not decrease with the increase of the switching frequency.

In this paper, the impedance model considering the parasitic parameters of the primary and secondary sides is calculated under light-load conditions, the limitations of the previous method are explained and a new circuit improvement is proposed.

In this paper, an improved circuit is proposed, and the impedance Bode plot is used to verify that the circuit can effectively improve the voltage gain problem under light-load conditions. Finally, the experimental results verify the effectiveness of the proposed circuit through comparison with traditional solutions and circuits.

In this paper, the impedance model considering the parasitic parameters of the primary and secondary sides is calculated, the limitations of the previous method are explained and a new circuit improvement is proposed. When compared with the previous method, the proposed circuit improvement can suppress the voltage gain increase that occurs when the switching frequency increases to a certain level.

This study aims to propose that the corrosion resistance of the neat epoxy coating can be further enhanced by incorporating reinforcing agents.

Chitosan, silica and their hybrid compound were used to study the subject of corrosion resistance of epoxy coating systems. This work used 3.5 Wt.% NaCl solution as the electrolyte, and electrochemical impedance spectroscopy (EIS) was used to investigate the electrochemical behaviour of the studied coating systems. Standard and accelerated states were used without and with scratch on the coating layer.

It was found that the impedance value of composite coating incorporated with the hybrid compound was significantly higher at 10¹⁰ Ω after 14 days of exposure in both testing states. The breakpoint frequency (f_b) determination also proves with large capacitive region at low-to-high frequency of impedance plots corresponding to the high corrosion resistance.

The hybrid compound consisting of chitosan as organic biopolymer and silica as inorganic material, respectively, served as a promising reinforcing agent for composite coating as a promising corrosion inhibitor. Different states of EIS measurement were used which are standard (without scratch) and accelerated (with scratch) states associated with the f_b values.

The purpose of this investigation was to develop sustainable resource-based anticorrosive coating material using Pongamia glabra seed oil and tannic acid (TA), as well as to improve the coating properties.

TA-modified fatty amide diol was synthesized by condensation polymerization. First, Pongamia glabra seed oil was converted to fatty amide diol (Pongamia oil fatty amide, PFA) that was further modified by TA with different parts per hundred of resin (10, 15 and 20) to develop a polyether fatty amide (PFA-TA). The confirmation of reaction between TA and PFA was carried out using Fourier transform infrared spectroscopy. The thermal behavior of PFA-TA was studied by thermogravimetric analyses. Coatings of several PFA-TA resins were applied to steel (i.e. plain carbon steel) coupons to investigate their physico-mechanical and anticorrosive performance. The corrosion protection performance was observed using AC impedance and polarization tests.

TA-modified fatty amide coatings showed the highest scratch hardness of 2.5 kg, flexibility (1/8 inch) and gloss at 45° was 60-62. Among all compositions, PFA-TA15 showed the best physico-mechanical and anticorrosion performance. Corrosion tests of coated panels were examined in different corrosive media (3.5 wt per cent HCl, 3.5 wt per cent NaOH and 5.0 wt per cent NaCl) using potentiodynamic polarization and AC impedance measurements. PFA-TA may find application as an eco-friendly protective coating, and thermal analyses revealed that it can be safely used up to 300°C.

This paper provides the development of protective coatings for steel from non-edible seed oil and TA to utilize sustainable resources.

The purpose of this paper is to develop the bio-composite organic coatings by adding the bio-based additives that are extracted from banana peels and henna leaves as the organic corrosion inhibitors.

Bioactive constituents with inhibition properties are extracted from banana peels and henna leaves by using ethanol to form the ethanolic extract. The inhibiting efficiency of these bioactive constituents on mild steel corrosion in 3.5% sodium hydroxide (NaCl) solution is investigated. The investigation is performed using electrochemical impedance studies for 30 days. The optical and adhesive properties of the bio-composite coating systems have also been studied.

The best protection is obtained as the loading ratio of the banana peels ethanolic extract (BPEE) and henna leaves ethanolic extract (HLEE) are 10 Wt.% and 30 Wt.%, respectively. Overall, the results obtained show that the BPEE and HLEE not only enhance the optical properties but also can serve as an effective inhibitor for corrosion without affecting the adhesiveness of the neat acrylic properties.

Banana peels and henna leaves consist of bioactive constituents that have anti-corrosion properties which could inhibit corrosion.

This paper aims to evaluate the corrosion inhibition capacities of synthesized compounds 1-(2-pyridinyl)-2-(o, m-, p-hydroxyphenyl) benzimidazoles in API 5L X52 steel/HCl 1M corrosion system.

Electrochemical impedance spectroscopy technique was used.

The studies determined that under stagnant conditions, the durability and efficiency were maintained over 80 per cent for up to 500 h of immersion, while the residence time started to decrease after 150 h at the best inhibitor concentration (150 ppm).

This work may help to attenuate corrosion problems in the petroleum industry.

It is the first time that 1-(2-pyridiniy)-2-(o-, m-, p-hydroxyphenyl) benzimidazoles were evaluated as corrosion inhibitors.

The purpose of this paper is to investigate the corrosion resistance of SiO₂-Al₂O₃ coating on mild steel.

SiO₂-Al₂O₃ was coated using sol-gel method, and electrochemical measurements were applied to assess the performance of the coated steel.

The main conclusion is that SiO₂-Al₂O₃-coated specimens acquired a higher corrosion resistance than that of uncoated specimen. i_corr values of the coated specimens were between 12 and 14 times smaller than those of uncoated specimen. The coated specimens exhibited a higher R_cor value at electrochemical impedance spectroscopy analysis. The high values of R_cor and low values of CPE_dl observed within the SiO₂-Al₂O₃-coated samples imply an improved anti-corrosion capability.

In this work, there are three points of originality. First, steel specimens were coated with ormosil-based solution by applying sol-gel dip coating method. Second, both SiO₂ and Al₂O₃ coatings were applied simultaneously at a considerably low temperature, i.e. 200 °C. Finally, the performance of the coated materials against wet corrosion was improved significantly.

Utilization of industrial and agricultural waste products as cement replacement materials in concrete technology has been an interesting subject of research for economical, environmental, and technical reasons. Portland cement incorporating these cement replacement materials improves corrosion resistance of carbon steel. Sugar cane bagasse is considered as waste in sugar mills and dumped in open space or used as fuel for boilers. The main purpose of the study is to investigate corrosion performance of reinforcing carbon steel in bagasse ash (BA) blended cement concrete and compare it with control concrete.

BA is prepared by burning boiler‐fired ash at a controlled temperature of 650°C for 1 h and cooled. The ash is then ground to a fineness of 46 μm as Pozzolanic material and blended in concrete in various cement replacement levels. The corrosion behaviour of carbon steel in BA blended concretes exposed to alternate dry‐wet cycles in 3.0 percent NaCl solution for 18 months was studied using gravimetric weight loss, linear polarization, and electrochemical impedance measurement techniques. The resistance to chloride ion penetration of BA blended concretes after 28 and 90 days and compressive strength of BA blended concrete cubes after 7, 14, 28, and 90 days curing also was evaluated.

The experimental results indicated that the corrosion rate of reinforcing steel and chloride penetration were significantly reduced, and compressive strength was increased, with the incorporation of BA up to 20 percent replacement in concrete. It was observed also that a relatively good correlation between linear polarization and impedance measurements with respect to corrosion current values on the reinforcing steel within BA blended concretes.

BA may be considered as a better substitute than other mineral admixtures for durable concrete structures. The study fulfilled the objective of the investigation and contributes to research on corrosion protection of carbon steel in concrete.

By adding a Ce salt and an Nd salt to an anodizing electrolyte, modified anodic films are obtained on aluminum surfaces. This paper aims to study the effects of rare‐earth elements on the corrosion resistance of the anode film.

The crystalline film was studied by X‐ray diffraction. The methods of scanning electron microscope, energy dispersive X‐ray analysis, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) were used to characterize the properties of the films.

After rare‐earth element modification, the pores of the porous layer were very evidently smaller, the anodic film was more compact, and the thickness and hardness of the films had increased. The corrosion resistance of the anodic films modified with rare‐earth elements clearly was improved in neutral, acidic, and basic NaCl solutions. Ce showed a better effect than Nd in increasing the corrosion resistance of the films, and the film modified with Ce+Nd showed the highest corrosion resistance. EIS analysis showed that the impedances of both the barrier layer and porous layer of the anodic films increased after modification with the rare‐earth elements, indicating that the anodizing process was affected by the presence of the rare‐earth elements.

The results presented in this paper offer a foundation for further research and application of rare‐earth elements in aluminum anodic oxide films.

The purpose of this paper is to evaluate the protection against corrosion of carbon steel SAE 1020 promoted by a niobium- and titanium-based coating produced from a resin obtained by the Pechini method.

A resin was prepared with ammonium niobium oxalate as niobium precursor and K₂TiF₆ as titanium precursor. Carbon Steel SAE 1020 plates were dip coated in the resin and calcinated for 1 h at 600 ºC. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to characterize the coating morphologically and structurally. Open circuit potential, electrochemical impedance spectroscopy, anodic potentiodynamic polarization and scanning vibrating electrode technique were used to evaluate the corrosion protection of the coating.

The electrochemical analyses evidence slight protection against corrosion of the coating by itself; however, the needle-like crystal structure obtained may potentially provide a good anchorage site, suggesting the coating could be used as a pretreatment that may present similar application to phosphating processes, generating lower environmental impacts.

Due to increasingly restrictive environmental laws, new environmentally friendlier surface treatments must be researched. This paper approaches this matter using a combination of niobium- and titanium-based coating, produced by a cleaner process, the Pechini method.