Advanced Materials Research Vols. 750-752

Abstract: With the combination of fractal theory and metallurgical properties of low silicon sinter, the influence of metallurgical properties in different content of R, MgO, SiO2 and C is analyzed on the condition of existing experiment and fuel, and by using the mercury intrusion machine it measured the volume of micro-pore structure after broken of low silicon sinter; and it combined with the multifractal theory measured multifractal spectrum for the pore structure, which is established the relationship between with the metallurgical properties and fractal theory.

Abstract: A tuning fork with piezoelectric (TFP) is an electro-mechanical device; its principle performance is based on specific frequency and limited voltage. As the principle, the device can result output significantly. This paper presents a material classification using phase difference value that is received from touching between material and modified TFP. For the modified TFP, it is customized by a millimeter needle. The frequency response method on Bode plot is used to observe the modified TFP behavior, and to select a specific frequency. The first-order model with cascade notch filters is employed to identify mathematical model of the TFP, and to verify the model by simulation. Experimentation is considered on 2 touching techniques: a shear-force type and a tapping mode type. There are hard plastic, iron, silicon rubber, vinyl eraser and hydrogel for test material. The results are described by both time series plots of input-output signals and numerical table of shifted phase. The technique can employed to classify the test materials effectively and explicitly.

Abstract: In this paper, electrochemical behaviour of Pb0.3%Ag0.06%Ca rolled alloy anode during the 6 days galvanostatic electrolysis in acid zinc sulphate electrolyte solution was investigated with Cyclic Voltammetry (CV) techniques. The phase composition of the anodic oxide layers during the electrolysis was observed using X-Ray Diffraction (XRD). The results revealed that with the increasing electrolysis time, the anodic peak (PbPbSO₄) is mainly present a rise trend in the first day electrolysis, thereafter, almostly keep a constant value. And the anodic peak (PbPbSO₄) gradually moved in the positive direction while the anodic peak (PbSO₄β-PbO₂, PbOα-PbO₂) strongly moved in the negative direction. The cathodic peak (β-PbO₂ and α-PbO₂PbSO₄) and (PbO and PbSO₄Pb) mainly present a rise trend and gradually moved in the negative direction. Besides, the corrosion phase of the anodic oxide layers mainly consist of PbSO₄, Pb, α-PbO₂ and PbS₂O₃. After electrolysis for 3 days, the major phase of the anodic oxide layers is PbSO₄ with a few Pb phase. When the electrolysis reaches the 6th day, the major phase of the anodic oxide layers is also PbSO₄ with a few α-PbO₂ phase. The preferred growth orientation of PbSO₄ is (021) ,(121) and (212) planes.

Abstract: With the iron and steel metallurgy, cement, ceramic and other industries making a rapid development, the refractory consumption in our country is quite large. So how to recycle the used refractory materials effectively is more and more important. In this experiment, the phase composition of ladle lining bricks at slag line, rampart and bottom were researched systematically, to determine the phase composition change between the unused and recycled materials. It turned out that the low melting point minerals CaMgSiO₄ and Ca₃Mg (SiO₄)₂ formed due to the reaction between MgO and the impurity compositions like SiO₂ and CaO from the melted slag and liquid steel. On the one hand, the formation of these low melting point minerals was one of the main reason for the damage of the recycled MgO-C ladle lining bricks. On the other hand, the alkaline magnesium carbon bricks had purification effect for the liquid steel as a result of the content reduction of SiO₂ and CaO.

Abstract: Acid sludge is one of the major oil field acidification increased production ineffective. Therefore, the acid sludge formation of influencing factors on improving acidification effect is of great importance. The Suizhong 36-1 oilfield is selected as the research object , a more in-depth study of the acid sludge formed in the acidification process influencing factors . The results show that: With the increase of crude oil in the colloid and asphaltene content , the amount of oleic acid mixture to form acid sludge also increases . Strong acid ionizing out of the higher concentration of H+ , the faster of the speed, the forming acid slag trend is obvious. The residual acid pH value increased , the amount of acid sludge also will continue to rise.

Abstract: Engineered materials could arrest aircrafts rushing out of runway, but its fragile and can be easily damaged by jet blast exhausted by taking off aircraft nearby. Engineered material unit coating and encapsulation were described in this paper, and a jet blast resistance experiment is designed to quantitatively measure the units resistant capability. In this experiment, a test bed built by units will receive a taking-off Boeing 737-300 aircrafts jet blast for over 60 seconds. The test order decreased distance from aircraft tail to the test bed. And the predicted air velocity and temperature was calculated through aircrafts characteristics contour. All the design made the experiment high reliable and economical. Experimental result indicated that the nearest distance from the test bed to aircraft tail could be 15 meters, and this experiment result has already been used for design of the arresting system in a Chinese civil airport.

Abstract: A novel QSPR model was proposed as to predict the gross heat of combustion of 32 nitro aromatic compounds. Genetic algorithm (GA) was applied to select the optimal subset of the molecular structures descriptors most related to gross heat of combustion. The multiple linear regression (MLR) was taken to build a prediction model of gross heat of combustion for the 32 compounds. The correlation coefficients (R²) together with correlation coefficient of the leave-one-out cross validation (Q²_CV) of the model is 0.997 and 0.995, respectively. The new model is highly statistically significant, and the robustness as well as internal prediction capability of which is satisfactory. This study can provide a new way for predicting the gross heat of combustion of nitro aromatic compounds for engineering.

Abstract: The plate of the heat exchanger leaked owing to its corrosion during the running of the whole equipment. The composition of the failure plate, microstructure, corrosion appearance and the chemical composition of the corrosion products were analyzed through Optical microscope, scanning electron microscope and chemical analysis method to find out the reason of the failure. The results show that the chemical composition of the plate meet the requirement of S31254 (254SMO) according to standard A240 /A240M-2005. The main phase was austenite among which the ferrite distributed in stripe. The corrosion happened firstly at the ferrite area under the condition of running medium with chlorine ion and sulfur ion. Incomplete solution of ferrite during the solid solution treatment was the main cause of spot corrosion, which ultimately resulted in the leaking failure owing to the corrosion.

Abstract: The experiments were done to find some good corrosion inhibitors for mild steel in 5% HF solution by the method of weight loss and electrochemistry including polarization curves and electrochemical impedance spectroscopy (EIS). Results show that the thiourea, potassium thiocyanate, and hexamethylenetetramine have good inhibition effect for mild steel in 5% HF solution, especially potassium thiocyanate and thiourea. Their corrosion resistance was greatly enhanced in the presence of tested inhibitor. Thiourea is an anodic type inhibitor and its inhibition efficiencies up to 99.88% can be obtained. Equivalent circuit of the investigated system was suggested.

Abstract: Dynamic response performance of PEMFC affects its durability and reliability significantly. So improving on dynamic performance of PEMFC has become the key for prolonging PEMFC life in fuel cell vehicles application. In this study, in order to promote the PEMFC dynamic response performance, RuO₂·xH₂O was prepared by solgel method and then sprayed onto catalyst layers. The RuO₂·xH₂O prepared was characterized by TEM, which shows the average particle size of RuO₂·xH₂O was 8 nm and particulates were well distributed. A 10-cell stack using MEAs with and without RuO₂·xH₂O was assembled and studied under different relative humidity. It was found that added with RuO₂·xH₂O dramatically improves the dynamic response performance, which revealing that RuO₂·xH₂O can buffer the voltage undershoot and improve the stability and lifetime of PEMFC stack.