Advanced Materials Research Vols. 415-417

Abstract: In order to solve the problem of mold powder entrapment which is one of the affecting factors on faint-sliver defect in IF cold-rolled steel sheet in casting process, continuous casting process is optimized. Based on the analysis of the defect, the composition of mold powder is optimized. Otherwise, surface tension and viscosity of mold powder are raised. With theses countermeasures, mold powder entrapment and casting subcutaneous slag is decreased obviously. In addition, the rate of faint-sliver defect in cold-rolled IF steel sheet has been reduced from 5.21% to below 1.0%.

Abstract: The modified single base gun propellant was prepared from single base propellant grain by impregnation with blasting oil, followed by deterring with deterrent in water medium. The concentration profile of function component in the propellant was studied by Fourier Transform Infrared (FTIR) Microspectroscopy. The combustion performance of the propellant was investigated by means of closed-bomb test and interior ballistic test. The barrel erosion was characterized by erosion tube test. It is found that the curve of nitroglycerine concentration is just like a parabola along the radius and the polymer ester concentration in the near surface of propellant decreases exponentially from the surface inwards. Compared with the single base gun propellant, the modified single base gun propellant burns more progressively and the value of Pr increases from 0.097 to 0.424. The interior ballistic performance for this propellant charge is improved obviously. The muzzle velocity increases by 5.0% from 886.6 m/s to 931.3 m/s. The modified single base gun propellant has the characteristic of low temperature sensitivity and the barrel erosion of this propellant decreases by 26.6% at least. The modified single base gun propellant has the advantages of higher muzzle velocity, higher combustion progressivity, low erosion and low temperature sensitivity.

Abstract: A pot experiment was conducted to investigate the effects of attapulgite clay, activated carbon, and liquid organic fertilizers used as soil amendments on cadmium (Cd) and lead (Pb) immobilization as well as on tobacco growth in contaminated soils. All three amendments reduced the amounts of DTPA-extractable Cd and Pb in soils as well as the concentrations of Cd and Pb in tobacco roots and leaves, compared to the control. Cadmium had a higher transportation index into tobacco leaves than Pb. DTPA-extractable Cd and Pb in soils was positively correlated with the metal concentrations in tobacco leaves, suggesting that DTPA-extractable Cd and Pb measurement could be a feasible method for assessing Cd and Pb bioavailability. Experimental results showed that upward trends of Soil and Plant Analyzer Development (SPAD) value in leaves were observed when tobaccos plants were grown in contaminated soils with increases of all the amendments. There were increases in root and shoot lengths as well as leaf area and dry weight for tobacco grown in amendment treated soils compared to the control.

Abstract: Natural polymer cationic flocculant was prepared by introducing quaternary ammonium group into the rice husk molecules, using potassium permanganate as initiator. The influence of synthetic conditions affecting flocculation was studied, such as reaction temperature, reaction time, dosage of initiator, concentration of sulfuric acid and material ratio. The flocculent experiment of diatomite was chosen to evaluate the capability of flocculant. The results show that the flocculant has good flocculent capacity, the removal of turbidity can reach above 90% for simulated wastewater under the optimistic conditions of synthetic process as follows: etherification temperature, 50°C; etherification time, 3h; initiator concentration, 3 mmol/L; sulfuric acid concentration, 1.8 mmol/L; ratio of rice husk to OTAC, 2: 3.

Abstract: Coupling agent KH-550 and KH-792 were used for surface modification of fumed silica to get amino group. And then the un- or modified SiO₂ blended with cellulose was added into N-methyl-morphine-oxide (NMMO), a kind of casting solvent, to form the cellulose solution for preparation of films. The modified film was characterized by fourier transform infrared(FTIR), scanning electron microscopy(SEM), mechanical tester and oxygen permeation analyzer. The results showed that the modified SiO₂ can be more evenly dispersed than that unmodified. The un- and modified SiO₂ all can improve the mechanical properties and oxygen permeation of cellulose film when the filled content is about 2wt% and the KH-792 is the best.

Abstract: The decolorization of coking wastewater is an urgent issue for coking wastewater treatment. Using mineral adsorbents to deal with the coking wastewater is an effective way to solve the above problem. In this paper, fluidized bed combustion (FBC) ashes, diatomite and clinoptiolite were used to decolorize the coking wastewater. UV-Vis was used to estimate the decolorization efficiency of the FBC ashes. The materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the sequence rule for the decolorization effect of three mineral adsorbents is FBC ashes > diatomite > clinoptiolite. In addition, the chroma of treated coking wastewater reduced from 320 times to less than 5 times in the comparison of raw wastewater. It is much lower than the chroma of GB8978-1996 1A discharge standard. The excellent decolorization effect of FBC ashes might be due to large contains of CaO and f-CaO.

Abstract: Li-doped (Na, K)NbO₃ lead-free piezoelectric ceramics with nominal composition of [Li_0.065(Na_0.535K_0.48)_0.95]NbO₃ were prepared by normal sintering method, and its phase structure, microstructure and electric properties were studied with a special emphasis on the influence of sintering temperature in the range of 950-1020 oC. The result of XRD analysis indicates that a polymorphic phase transition (PPT) separating orthorhombic and tetragonal phases was found at the temperature of 950 oC, whereby enhanced piezoelectric properties of d₃₃=255 pC/N and k_p= 44.5% were obtained although the density was low. Our study indicates that the importance of PPT for enhancing electric properties in niobate-based ceramics at low temperature.

Abstract: In order to improve the electrochemical cycle stability of the La-Mg-Ni system A₂B₇-type electrode alloys, La in the alloy was partially substituted by Zr. The melt-spinning technology was used for preparing La_0.75−xZr_xMg_0.25Ni_3.2Co_0.2Al_0.1 (x = 0, 0.05, 0.1, 0.15, 0.2) electrode alloys. The influences of both the substitution of Zr for La and the melt spinning on the structures and the electrochemical cycle stability of the alloys were investigated in detail. The structure analysis of XRD, SEM and TEM reveals that the as-cast and spun alloys have a multiphase structure, composing of two main phases (La, Mg)₂Ni₇ and LaNi₅ as well as a residual phase LaNi2. The substitution of Zr for La facilitates to form a like amorphous structure in the as-spun alloy without altering the structures of two major phases. The electrochemical measurement indicates that both the substitution of Zr for La and the melt spinning remarkably improves cycle stability of the alloys. The capacity retaining rate (S₁₀₀) of the Zr_0.2 alloy at 100th charging/discharging cycle is enhanced from 76.69 to 85.18% by growing spinning rate from 0 (as-cast was defined as the spinning rate of 0 m/s) to 30 m/s. And that of the as-spun (10 m/s) alloys is increased from 69.25 to 83.09% by rising Zr content from 0 to 0.2.

Abstract: Positive-electrode material LiFePO₄/C was prepared using FePO₄•2H₂O as raw material via a rheological phase method. Orthogonal experiment was designed to systematically investigate the effects of the ratio of raw materials, calcining temperature and holding time on the morphology and electrochemical performance of LiFePO₄/C. The results showed that the optimal parameters were as follows: synthesis temperature 650 °C, time 10 h. The sample prepared with optimal parameters showed discharge capacities of 147.5 mAh•g^-1 at 0.2 C and 133.7 mAh•g^-1 at 1 C rate, with good cycle performance.

Abstract: Cassava is one of the most important crops in Nakhon Ratchasima province which grows the most cassava in the Northeast of Thailand. Therefore, a large amount of cassava rhizome is left in the field after harvest. The objectives of this research were to study the potential of using residue biomass from the cassava crop i.e. cassava rhizomes. The physical properties and heating value of the cassava rhizomes were evaluated and compared with perennials. The analysis consisted of proximate analysis to measure moisture content, ash, volatile matter and fixed carbon. Heating values were measured using the IKA*C5003 automatic bomb calorimeter. The results were that for high moisture content of about 49-52% the cassava rhizomes had properties inferior to the perennials. When the moisture content of the rhizomes was reduced until around 12%, the properties were equivalent to those of wood samples that had about 2% moisture content. The proximate analyses gave ash 1.8-2.8%, volatile matter 72-75% and fixed carbon 9-13%. Moreover, its average heating values were around 17.08 MJ/kg, while the wood samples were around 17.78 MJ/kg. It appears that cassava rhizome has a high potential as an energy source. Using it to replace wood fuel is possible but it is necessary to reduce the moisture content to an appropriate level.