Narrow Results

It is important that the steel plate is manufactured with a high tensile strength to reduce the weight of the body. It is generally accepted that twinning induced plasticity (TWIP) steel is a special steel with not only a high ductility but also a high-tensile strength compared to general steel. While numerous investigations have been carried out on the TWIP steel with an amount of manganese of at least 20%, the investigation of steel with manganese content of less than 20% has seldom been considered until now. In this study, the TWIP steel with manganese of less than 20% (12Mn, 15Mn and 18Mn TWIP steel) was investigated to determine the corrosion properties using electrochemical method. The 18Mn and 12Mn samples exhibited the best and worst corrosion resistance, respectively. It is suggested that the 18Mn sample forms a stable oxide film on the surface because it contains a larger amount of manganese and aluminum compared to the other samples, and their composition enables the easy formation of the oxide film.

An optimum repair welding for the piston crown which is one of the engine parts exposed to the combustion chamber is considered to be very important to prolong the engine lifetime from an economical point of view. In this study, two types of filler metals such as 1.25Cr–0.5Mo, 0.5Mo were welded with SMAW method and the other two types of filler metals such as Inconel 625 and 718 were welded with GTAW method, respectively, and the used base metals were the cast and forged steels of the piston crown material. The weld metal zones welded with Inconel 625 and 718 filler metals exhibited higher corrosion resistance compared to 1.25Cr–0.5Mo and 0.5Mo filler metals. In particular, the weld metal zone welded with Inconel 718 and 0.5Mo, filler metals indicated the best and worst corrosion resistance, respectively. Consequently, it is suggested that the corrosion resistance of the weld metal zone surely depends on the chemical components of each filler metal and welding method irrespective of the types of piston crown material.

The extraction of linseed oil (LO) was realized by refluxing method. The extracted oil was identified by gas chromatography method coupled with mass spectrometry (GC-MS). In order to contribute to the protection of the environment, one contemplates to try on LO as a green corrosion inhibitor. The corrosion inhibition of LO was studied by weight loss and electrochemical methods. The obtained results showed that the LO is an effective inhibitor of the carbon steel corrosion in 1M HCl solution, the inhibition efficiency increased with concentration to reach 88% at 200ppm. Furthermore, the adsorption of the inhibitor on the surface of metal in 1M HCl solution was found to obey Langmuir’s adsorption isotherm. The influences of temperature were also studied in the range from 298K to 328K. The kinetic and thermodynamic data of activation dissolution process were determined and discussed.

In this work manganese dioxide (Ramsdellite-MnO₂) was synthesized at room temperature using a facile electrochemical method. X-ray diffraction (XRD) was used to identify the type and the size of the crystal particle, while field emission scanning electron microscopy (FESEM) and energy filtered transmission electron microscopy (EFTEM) were used to show and identify the morphology of the particles and changes of their morphologies with the increase of reaction times. Fourier transform infrared (FTIR) spectroscopy confirmed the Mn–O bond. Results from XRD showed that optimum time for synthesis Ramsdellite-MnO₂ was 9 h. The results of EFTEM showed a mixture of nanospheres and nanorods after 9 h reaction time while a homogenous morphology of nanospheres was detected at 12 h reaction time. Results confirmed on the existence of a correlation between the reaction time and the resulting nanostructures. Moreover, the EFTEM result showed that average particle size for 12 h was (25 ± 7 nm). The variation of calculated specific capacitance (F/g) versus the different scan rate has indicated that the efficiency of synthesized Ramsdellite-MnO₂ nanostructures in 12 h reaction time was superior to 9 h.

The transition of graphene from the lab to consumer goods is still a challenging job that necessitates efficient and cost-effective large-scale graphene production. This study combines electrochemical exfoliation in an aqueous solution of sulfuric acid (1M H₂SO${}_4)$ and hydrogen peroxide (3% H₂O${}_2)$ followed by thermal deoxygenation at a temperature of 800${}^{\circ }$C within the ambient environment. This method allows the inexpensive synthesis of pristine graphene for various industrial applications. X-Ray diffraction (XRD) results for pristine graphene showed a distinct peak at 2$𝜃=26.39^{\circ }$ with a corresponding interplanar distance ($d_{\mathrm{\text{hkl}}})$ of 3.3754 Å and a crystallite size of 18 nm. XRD statistics indicated that the crystal structure of the original graphene was preserved. The crystalline structure was recovered and the interplaner distance was decreased following the high temperature thermal reduction. According to Raman spectroscopy, the impurity degree (I${}_D$/I${}_G)$ region fraction of pristine graphene was 0.211. This indicates that the original graph produced by the current method has little distortion. Raman analysis shows that there is a linear red shift in peaks D-band (D), G-band (G), and second order of the D-band (2D) due to the increase in phonon–phonon nonlinear interactions with increasing temperature, so that peaks (D), (G) and (2D) shifts are shown. The majority of the functional groups were discovered to be eliminated after high temperature thermal treatment. The three-dimensional graphene sheet is highly defined and intricately coupled in the microstructure analysis, resulting in a laxer and porous structure. When treated at a temperature below 800${}^{\circ }$C, there was only minor damage to the reduced graphene oxide (RGO) microstructure. The results of the Atom Force Microscope (AFM) demonstrated that the flaws spread over time from the layer boundaries and pores to the edges and eventually resulted in a separate RGO archipelago. According to TGA analysis, at temperatures up to 800${}^{\circ }$C, the RGO sheet loses up to 45% of its weight.

An electrochemical detection of inositol content using platinum (Pt)-based noble metal electrode is investigated. In this work, the electrochemical behavior of the platinum electrode has been studied and analyzed using a three-electrode system against a silver–silver chloride (Ag/AgCl) reference electrode and a steel counter electrode. Differential pulse voltammetry technique has been employed for this experimental study. A satisfactory linear range of operation was obtained from 50 to 400$\mu$M with $\mathrm{\text{LOD}}=19.28\mu$M. Electrochemical responses for several inositol concentrations 50, 80, 100, 200, 300 and 400$\mu$M have also been analyzed using principal component analysis (PCA) with effective data clustering. A good class separability index (SI) was found to be 142.91. In addition, a prediction estimation of inositol contents using partial least square regression (PLSR) and principal component regression (PCR) algorithms were also evaluated and prediction accuracies of 93.69% and 93.71% were obtained, respectively. Moreover, the application of the Pt electrode over real orange juice sample extracts revealed satisfactory recovery rate of 96.18%. Thus, this technique of electrochemical system may be subjected for inositol detection in our daily-life food (especially juice, beverages) consumption.

Adding impurity ions to the body phase of spinel LiMn₂O₄ is a useful measurement to improve its electrochemical performances. Surface treatment is also a possible solution for mending the cathode materials. In this study, an electrochemical method was used to modify the spinel LiMn₂O₄. Here potassium fluoride aqueous solution was used as the electrolyte, LiMn₂O₄ film and nickel film were served as the working electrode and counter electrode, respectively. With a charge current of 100µA, the LiMn₂O₄ films were treated for several hours in the electrolyte system, then washed by distilled water to remove the residual electrolyte, followed by vacuum drying under 55°C. X-ray photoelectron spectroscopy (XPS) indicates that the fluorine anions had appear on the surface of LiMn₂O₄ after the electrochemical process. Scanning electron microscope (SEM) images show that the apparent morphology of these cathode material particles had been changed. Galvanostatic charge-discharge curves show the charge-discharge plateaus of the anion-modified spinel LiMn₂O₄ are different from those of untreated one. The influences of the modification on the properties of spinel are discussed in detail.

In this paper, the design of the lower computer hardware circuit for the heavy metal detector based on electrochemical method is introduced. Firstly, the whole instrument is described according to the system structure, and then main parts are introduced from the principles and the specific circuits. After assembling the prototype, the performance of the system is tested. And the result shows that the system operates very well and could meet the needs of actual measurement. With the simple structure and high accuracy, the circuit design can be used as the basic structure for the expanding applications.