Solid Ar, N2, CO, and O2 in Nanopores

Molecular solids enclosed in pores with diameters in the nm-range are a research field which attracts growing interest. The major questions asked in this context are: what is the structure and the dynamics? How are phase and glass transitions modified by the geometrical constraint? In this contribution we present structural information, by x-ray diffraction measurements, as well as thermodynamic characterization, by vapor pressure and heat capacity measurements, on Ar, which is usually considered the simplest of all condensates, and on the small diatomic molecules N₂, C0, O₂ in porous glasses with average pore diameters from 50 to 130Å.     

Quantitative CARS spectroscopy of CO2 and N2O

Experimental and theoretical investigations of the CARS spectroscopy of CO2(2v2) and N2O(v3) were carried out. The experimental spectra were measured in a heated test cell, and excellent agreement with the observed temperature dependences was obtained from numerical simulations. Assignments were made for all hot bands, and the role of collisional narrowing was quantified. Observed nonresonant susceptibility effects in pure N2O have made it possible to estimate the nonresonant background susceptibility for this molecule by using the resonant contribution as a reference calibration.     

N2 and CO vibrational CARS and H2 rotational CARS spectroscopy of CH4/N2O flames

Broadband CARS spectra of N2 and CO have been obtained from the postflame gases of rich CH4/N2O flames using the nonplanar BOXCARS technique. The temperature and concentration of both N2 and CO in these flames were estimated from CARS spectra with the aid of model calculations and agreed with standard thermochemical predictions. In addition, several pure rotational H2 CARS transitions, certain of which had been previously unobserved, were seen in several spectral regions, most notably in both the CO and NO CARS regions. These observations are important in future modeling of CARS data.     

Grinding characteristics of coal and petroleum coke/coal blends on utilization for combustion

ABSTRACT

Petroleum coke (PC) blend with coal is an attractive feedstock for combustion process. The present work investigates the grinding characteristics of PC blend with coal in a laboratory ball mill to meet an industrial tube mill conditions. Tests were carried out using a laboratory batch ball mill for optimal production of ?200 mesh size product. The ground products at different combinations were subjected to sink-float tests. Experimental results suggested that the petcoke with coal at 5.0% blend ratio was optimum for generation of ?200 mesh size product. It was also observed that increasing coal/petcoke blend ratio beyond 5.0% leads to a decrease in ?200 mesh size generation. The better performance could be achieved at the blending ratio of 5%, perhaps resulting from the synergistic effect of the blends. With the aforementioned blend ratio, the optimal condition of the milling time was found to be 3 h. The percentage of coal to the total charge and percentage of petcoke to the total charge of the ball mill product at various blends were also calculated for all the blends and at all grinding time intervals. The results obtained could provide a useful insight to predict the industrial mill performance.     

Effects of annealing gas (N2, N2O,O2) on the characteristics of ZrSixOy/ZrO2 high-k gate oxide in MOS devices

We investigated the effects of annealing gas on the physical and electrical properties of ZrSi_xO_y/ZrO₂ high-k gate oxide. We found that the post oxidation annealing under oxidizing ambient (e.g., N₂O or O₂) results in the additional interfacial oxide layer between silicate film and Si substrate, causing the degradation of equivalent oxide thickness (EOT) property. On the other hand, no clear evidence for the growth of interfacial oxide layer was observed if annealing was performed in N₂ ambient. Furthermore, we found that N₂ annealing effectively annihilates the defect center in ZrSi_xO_y/ZrO₂ layer. Therefore, we suggest that annealing in N₂ ambient is necessary to improve the characteristics of ZrSi_xO_y/ZrO₂ high-k gate oxide.     

Recovering CO2 and N2 from combustion exhaust gas use membrane technology

Enerfex, Inc. is a start-up company actively involved in various process development and design activities. Most of Enerfex's processes involve gas separation membranes. Enerfex holds the patent on the Cryocogen process and apparatus that allows the application of membranes to combustion exhaust gas. Cryocogen technology is the application of gas separation membranes to combustion exhaust gas to simultaneously produce high purity carbon dioxide and nitrogen. The system is described here.     

Measurements of CO, CO2, OH, and H2O in room-temperature and combustion gases by use of a broadly current-tuned multisection InGaAsP diode laser

A new laser technology that achieves nearly 100-nm quasi-continuous tuning with only injection-current control in a four-section grating-coupler sampled-reflector laser was used to detect CO and CO(2) simultaneously in room-temperature gas mixtures. The same grating-coupler sampled-reflector laser was used to perform in situ measurements of CO, H(2)O, and OH in the exhaust gases of a CH(4)-air flame. This laser is being evaluated for inclusion in a multispecies combustion-emissions exhaust-analysis sensor, and its operational characteristics as they have an impact on gas sensing are described. Preliminary results suggest that this single laser can be used to replace multilaser sensor configurations for some combustion-emissions monitoring applications.     

大同煤循环流化床的O_2-CO_2预热特性

利用循环流化床高温预热技术,对大同煤在O_2-CO_2环境下预热前后的颗粒特性、燃料特性和燃料氮的转化特性开展研究。结果表明,循环流化床可将大同煤稳定预热至850℃,预热所需的热量全部由煤粉自身的部分燃烧提供。预热后的半焦颗粒粒径减小,比表面积和孔容积分别增大10和2倍,孔隙结构更加发达;大同煤在循环流化床O_2-CO_2预热中,煤气中CO、H_2、CH_4和CO_2体积分数分别为11.5%,9.7%,2.11%和79.6%,煤气热值为2 848.7 kJ·m~(-3);预热过程,煤中的N-Q和N-X向N-6和N-5发生了转化,N-6质量分数由原煤的17.28%增大到32.11%。     

MgO/La2O3CO3复合材料对磷酸盐的吸附特征

采用水热法制备了MgO/La2 O2 CO3复合材料(ML).采用X射线衍射仪和扫描电子显微镜对其结构及表面形貌进行了表征,利用Zeta电位仪测定了其零点电位点,并探究了接触时间、初始磷酸盐浓度和初始pH对磷酸盐吸附效果的影响.结果 表明,ML呈现板块状堆叠而成的层状结构,零点电位点为4.52.准二级动力学模型和Fre...     

Crystallization of amorphous Zr-Ni alloys in the presence of H2, CO,O2, N2 and argon gases

The gas absorption and crystallization behaviour of melt-quenched amorphous Zr₃7Ni₆₃ and Zr₆₇Ni₃₃ alloys in H₂, CO, O₂, N₂ and argon atmospheres were investigated. Unexpectedly, the nickel-rich amorphous alloy was more reactive than the zirconium-rich one. Thus, a-Zr₃₇Ni₆₃ can absorb hydrogen, form the metastable tetragonal ZrO₂ by oxidation and decompose into the non-equilibrium nickel, ZrC, ZrO₂(T) and ZrO₂(M) phases in CO atmosphere below its crystallization temperature. However, neither absorption of N2 nor formation of ZrN was detected. On the contrary, the a-Zr₆₇N₃₃ alloy hardly reacts with gases below its crystallization temperature. The role of the surface oxide layer in gas absorption is discussed.     

Mineral sequestration of CO(2) by aqueous carbonation of coal combustion fly-ash

The binary adsorption of Cu(2+)-Cd(2+), Pb(2+)-Cd(2+) and Pb(2+)-Cu(2+) mixtures onto Ca-Alginate beads, prepared from Laminaria digitata, was studied using batch experiments. Competitive sorption models including extended Sips, extended Langmuir, Jain and Snoeyink modified Langmuir (JS modified) as well as Ideal Adsorpted Solution Theory (IAST) models were applied to predict the binary adsorption using single component adsorption parameters. The extended and the JS modified Langmuir approaches provide excellent prediction of the binary adsorption, while the extended Sips fails to predict the experimental data, giving only fair results in the case on Pb(2+)-Cu(2+) mixtures. On the contrary, the IAST models, though they are more complicated, provide less accurate estimation of sorption in binary metal ion solutions. In general, single component adsorption parameters can be effectively used for the prediction of a materials adsorption performance in binary metal ion solutions.     

Preparation and microwave absorption characteristics of MoS2/Nd2O2CO3 composites

Journal of Materials Science: Materials in Electronics - The neodymium oxide carbonate (Nd2O2CO3) was prepared from neodymium hydroxide (Nd(OH)3) by hydrothermal and 550 °C heat treatment....     

Precision refractive index measurements of air, N2, O2, Ar, and CO2 with a frequency comb

We report precision measurements of the refractive indices of dry air, N(2), O(2), Ar, and CO(2), performed by using a frequency comb as the light source in a Mach-Zehnder interferometer setup. Improved dispersion formulas for all gases are derived with a sensitivity level of 10(-9). These results are valid for a wavelength range from 740 to 860 nm and are in good agreement with measurements from other groups.     

Liquid-in-Aerogel Porous Composite Allows Efficient CO2 Capture and CO2/N2 Separation

The pursuit of efficient CO₂ capture materials remains an unmet challenge. Especially, meeting both high sorption capacity and fast uptake kinetics is an ongoing effort in the development of CO₂ sorbents. Here, a strategy to exploit liquid-in-aerogel porous composites (LIAPCs) that allow for highly effective CO₂ capture and selective CO₂/N₂ separation, is reported. Interestingly, the functional liquid tetraethylenepentamine (TEPA) is partially filled into the air pockets of SiO₂ aerogel with left permanent porosity. Notably, the confined liquid thickness is 10.9–19.5 nm, which can be vividly probed by the atomic force microscope and rationalized by tailoring the liquid composition and amount. LIAPCs achieve high affinity between the functional liquid and solid porous counterpart, good structure integrity, and robust thermal stability. LIAPCs exhibit superb CO₂ uptake capacity (5.44 mmol g⁻¹, 75 °C, and 15 vol% CO₂), fast sorption kinetics, and high amine efficiency. Furthermore, LIAPCs ensure long-term adsorption–desorption cycle stability and offer exceptional CO₂/N₂ selectivity both in dry and humid conditions, with a separation factor up to 1182.68 at a humidity of 1%. This approach offers the prospect of efficient CO₂ capture and gas separation, shedding light on new possibilities to make the next-generation sorption materials for CO₂ utilization.     

Precision trace gas analysis by FT-IR spectroscopy. 1. Simultaneous analysis of CO2, CH4, N2O, and CO in air

We report the development of a method of trace gas analysis based on 1-cm-1 resolution Fourier transform infrared (FT-IR) spectroscopy, deployable in both laboratory and field applications. Carbon dioxide, methane, nitrous oxide, and carbon monoxide may be analyzed simultaneously in a single air sample using this method. We have demonstrated that the method can provide analytical precision of the order of +/- 0.15 mumol mol-1 for CO2, +/- 0.9 nmol mol-1 for CH4, +/- 0.3 nmol mol-1 for N2O, and +/- 0.3 nmol mol-1 for CO, expressed as mole fractions in dry air. The analytical precision is in all cases competitive with or superior to that of the more usual methods of analysis for these trace gases, namely, nondispersive infrared spectroscopy for CO2 and gas chromatography-based techniques for CH4, N2O, and CO. The novel FT-IR method relies on calibration using synthetically calculated absorbance spectra and a chemometric multivariate calibration algorithm, classical least squares.     

Pd/SiO2有机-无机薄膜的制备及其在N2气氛中的热稳定性

采用溶胶-凝胶法,在甲基化改性SiO2溶胶中掺杂PdCl2,制备Pd/SiO2有机-无机薄膜.通过XRD、红外光谱、TG-DTG分析、接触角以及SEM测试,考察该样品在N2气氛中的热稳定性.结果表明,Pd/SiO2膜材料经200℃以上温度焙烧后,样品中即出现了少量纳米金属Pd粒子,这些金属Pd为PdCl2还原所得.随着焙烧温度的升高,金属Pd粒子的衍射峰强度增加,膜材料中的Si-CH3吸收峰和Si-OH吸收峰减弱.样品中的Si-CH3吸收峰在750℃时完全消失.金属Pd的掺杂对SiO2膜材料的化学结构基本没影响.保持Pd/SiO2有机-无机薄膜及分离膜疏水性的最适宜焙烧温度为350℃.     

Constructing BiOBr/g-C3N4/Bi2O2CO3 Z-scheme photocatalyst with enhanced photocatalytic activity

Journal of Materials Science: Materials in Electronics - In this work, the novel camellia-structured double Z-scheme BiOBr/g-C3N4/Bi2O2CO3 was simply prepared by a hydrothermal method. XRD, FTIR,...