Hydrothermal Synthesis of SBA-15 Using Sodium Silicate Derived from Coal Gangue

Well-ordered SBA-15 was prepared with a hydrothermal route by sodium silicate derived from coal gangue. The as-prepared sample was analyzed by SAXRD, BET, TEM, and SEM, respectively. The results indicate that at a low hydrothermal temperature of 100∘C the well-ordered mesoporous SBA-15 could be synthesized. The surface area, pore volume, and pore size of the sample are 552 m2/g, 0.54 cm3/g, and 7.0 nm, respectively. It is suggested that coal gangue could be used in obtaining an Si source to prepare mesoporous materials, such as SBA-15

A Comparison of Iron and Steel Production Energy Use and Energy Intensity in China and the U.S.

Production of iron and steel is an energy-intensive manufacturing process. In 2006, the iron and steel industry accounted for 13.6% and 1.4% of primary energy consumption in China and the U.S., respectively (U.S. DOE/EIA, 2010a; Zhang et al., 2010). The energy efficiency of steel production has a direct impact on overall energy consumption and related carbon dioxide (CO2) emissions. The goal of this study is to develop a methodology for making an accurate comparison of the energy intensity (energy use per unit of steel produced) of steel production. The methodology is applied to the steel industry in China and the U.S. The methodology addresses issues related to boundary definitions, conversion factors, and indicators in order to develop a common framework for comparing steel industry energy use. This study uses a bottom-up, physical-based method to compare the energy intensity of China and U.S. crude steel production in 2006. This year was chosen in order to maximize the availability of comparable steel-sector data. However, data published in China and the U.S. are not always consistent in terms of analytical scope, conversion factors, and information on adoption of energy-saving technologies. This study is primarily based on published annual data from the China Iron & Steel Association and National Bureau of Statistics in China and the Energy Information Agency in the U.S. This report found that the energy intensity of steel production is lower in the United States than China primarily due to structural differences in the steel industry in these two countries. In order to understand the differences in energy intensity of steel production in both countries, this report identified key determinants of sector energy use in both countries. Five determinants analyzed in this report include: share of electric arc furnaces in total steel production, sector penetration of energy-efficiency technologies, scale of production equipment, fuel shares in the iron and steel industry, and final steel product mix in both countries. The share of lower energy intensity electric arc furnace production in each country was a key determinant of total steel sector energy efficiency. Overall steel sector structure, in terms of average plant vintage and production capacity, is also an important variable though data were not available to quantify this in a scenario. The methodology developed in this report, along with the accompanying quantitative and qualitative analyses, provides a foundation for comparative international assessment of steel sector energy intensity

Time fractional modified KdV-type equations: Lie symmetries, exact solutions and conservation laws

In the paper, we research a time fractional modified KdV-type equations.We give the symmetry reductions and exact solutions of the equations, and we investigate the convergence of the solutions. In addition, the conservation laws of the equations are constructed

Reactor performance and membrane fouling of a novel submerged aerobic granular sludge membrane bioreactor during long-term operation

The aerobic granular sludge membrane bioreactor (AGS-MBR) has the potential for simultaneous carbon/nitrogen removal and membrane fouling mitigation. Most studies have focused on comparison of granular sludge MBR and flocculent sludge MBR in short-term tests using synthetic wastewater. In this study, two identical AGS-MBRs were developed, and the reactor performance and membrane fouling were examined systemically over 120 days for synthetic wastewater and municipal sewage treatment, respectively. Results showed that regular granules with good settling ability were developed and maintained throughout the experimental period. Regardless of the substrate type, AGS-MBR demonstrated a stable removal of carbon (85–95%) and nitrogen (50–55%) in long-term operation. In addition, the membrane fouling propensity is apparently lower in AGS-MBRs with no membrane cleaning for 4 months at a flux of 20 L m−2h−1. The filtration resistance analysis indicates that the main membrane resistance was caused by irreversible fouling in both of the reactors. Membrane foulant analysis indicates that proteins in extracellular polymeric substances are more prone to be attached by the membrane of AGS-MBRs because of their hydrophobic nature. This study shows that AGS-MBR is effective and stable for municipal sewage treatment and reuse during long-term operation

Solubility of Li2CO3 in Na-K-Li-Cl brines from 20 to 90 degrees C

The solubility of Li2CO3 in Na-K-Li-Cl brines was measured by isothermal dissolution method within the temperature range of 20 to 90 degrees C. It was found the solubility of Li2CO3 in all systems investigated decreased with increasing temperature. In NaCl and KCl solutions, the solubility of Li2CO3 initially increased to a maximum value and then decreased gradually with increasing solution concentration. However, the solubility of Li2CO3 in LiCl solutions decreased with increasing LiCl concentration due to the common ion effect of added Li+. New Pitzer activity coefficient model parameters for the Li+-CO32- ion pair were obtained by using experimental solubility data of Li2CO3 in pure water, and a new chemical model was built with the aid of Aspen Plus platform. The new model was shown to successfully predict the solubility of Li2CO3 in NaCl, KCl, LiCl and mixed NaCl-KCl solutions. Moreover, the new model could aid in analyzing the separation of lithium and magnesium in brines. (c) 2013 Elsevier Ltd. All rights reserved

Random X-chromosome inactivation dynamics in vivo by single-cell RNA sequencing

Abstract Background Random X-chromosome inactivation (rXCI) is important for the maintenance of normal somatic cell functions in female eutherian mammals. The dynamics of X-chromosome inactivation initiation has been widely studied by assessing embryonic stem cell differentiation in vitro. To investigate the phenomenon in vivo, we applied RNA sequencing to single cells from female embryos obtained from a natural intercrossing of two genetically distant mouse strains. Instead of artificially assigning the parental origin of the inactive X chromosome, the inactive X chromosomes in this study were randomly selected from the natural developmental periods and thus included both paternal and maternal origins. Results The rXCI stages of single cells from the same developmental stage showed heterogeneity. The high resolution of the rXCI dynamics was exhibited. The inactivation orders of X chromosomal genes were determined by their functions, expression levels, and locations; generally, the inactivation order did not exhibit a parental origin preference. New escape genes were identified. Ohno\u2019s hypothesis of dosage compensation was refuted by our post-implantation stage data. Conclusions We found the inactivation orders of X chromosomal genes were determined by their own properties. Generally, the inactivation order did not exhibit a parental origin preference. It provided insights into the gene silencing dynamics during rXCI in vivo

Enhanced phenol removal in an innovative lignite activated coke-assisted biological process

In this study, a lignite activated coke (LAC)-assisted activated sludge (AS) process was developed for enhancing biodegradation of phenol, while the effects of LAC on sludge properties and microbial community structure were investigated. It was found that more than 90% of phenol was removed within 1 h in the LAC/AS, which was 3 times higher than the conventional AS process. Moreover, the floc size and settleability were also significantly improved in the LAC/AS. These results suggested that LAC could serve as the nucleating agent to promote the formation of compact floc, which was beneficial for toxicity mitigation and system stability. The microbial community analysis by 16S high-throughput pyrosequencing technology further revealed a more abundant bacterial richness and diversity in the LAC/AS process loaded with phenol, while some phenol degraders, such as Propionibacteriaceae were enriched. Engineering implications further suggests the LAC-assisted AS process is technically sound and economically viable