Investigation of Ash Deposition During Co-Firing Biomass/Peat with Coal in a Pilot-Scale Fluidized-Bed Reactor

Biomass, a promising alternative to fossil fuels, has been applied widely for energy generation by co-firing technology in recent year particularly in the EU countries. In this thesis, a key issue of biomass co-firing technology - ash deposition in combustion, co-combustion and gasification, was comprehensively investigated in a pilot-scale bubbling fluidized bed reactor. A custom-designed, air-cooled probe was installed in the freeboard zone of the reactor to simulate the heat-transfer surface and collect ash deposits from the process. A local lignite coal, a woody biomass (white pine), and a Canadian peat were involved in the tests. The main varying operating parameters investigated in this study included: blending ratio, air/fuel ratio, moisture content and sulphur addition for the combustion/combustion tests; equivalence ratio, bed materials and fuel types for the gasification tests. A new parameter, relative deposition rate (RDA) was proposed in this study to evaluate the relative deposition tendencies of biomass fuels and biomass-coal mixed fuels against the coal as the base fuel for co-firing. As expected, co-firing of the lignite and the wood pellets (with a much lower ash-content than the lignite) resulted in a decreased superficial rate of ash deposition. However, co-firing of woody biomass and lignite coal did not significantly increase the ash deposition tendency in terms of the values of RDA, and more interestingly, co-firing of the fuel blend of 50% lignite-50% white pine pellets produced a lower RDA. Co-combustion of three-fuel blend at 20%lignite-40%peat-40%pine resulted in the lowest deposition rate and the least deposition tendency among all the combustion tests with various mixed fuels or individual fuels. Another new and interesting discovery of this study was that fluidized-bed combustion of an individual fuel or a fuel blend with a higher moisture content produced not only a more uniform temperature profile along the fluidized-bed column but also a reduced ash deposition rate. A higher chlorine concentration in the feed would generally result in a higher tendency of ash deposition. Adding sulfur into the fuel of coal or peat could effectively decrease the chloride deposition in the ash deposits via sulphation. The sulphur addition could also reduce the ash deposition rate for the combustion of lignite, while it slightly increased the ash deposition rate for the peat fuel. In air-blown gasification of a woody biomass and a Canadian peat, the experimental results demonstrated that among the four bed materials (olivine, limestone, iron ore, and dolomite), the use of olivine resulted in the lowest ash deposition rate. The superb performance of olivine in retarding ash deposition could be accounted for by its outstanding thermal stability and mechanical strength. The other three bed materials, in particular limestone, were fragile during the fluidized bed gasification, and the fractured fines from the bed materials were found to deposit along with the fuel-ash on the heat transfer surface, leading to higher ash deposition rates. Finally, mathematical models parameterized with interactions between fuel chlorine, alkali and ash particles were developed to analyze the ash and chlorine deposition behavior based on the experimental data from co-firing peat with lignite coal. The developed equations in this study can not only describe the dependence of the deposition rate and the ash chlorine content on the fraction of peat, but can also determine suitable range of the peat fraction for smooth operations, which would be useful for co-firing other fuel blends

Removal of pharmaceutically active compounds from water systems using freeze concentration / by Yuanyuan Shao.

In the last few years, there has been a growing concern in the occurrence of pharmaceutically active compounds in the aquatic environment. Just in Europe, more than 3000 prescription and non-prescription drugs are used by human and animals and more than 80 drugs have been detected in municipal wastewater treatment plant effluent, surface water, groundwater, and in a few isolated cases, in drinking water, some at alarmingly high concentrations. Although no known human health effects have been associated with exposure to drinking water containing trace concentrations of drug residues, there is concrete evidence that these drug residues could cause numerous adverse health effects on aquatic life, even at very low concentrations. Municipal wastewater treatment plant effluents have been identified as the major source of drug residues in surface waters. Conventional wastewater treatment systems cannot effectively remove pharmaceutically active compounds. The suitability of distinct wastewater treatment processes for the elimination of drug residues has not been studied. Freezing has been used successfully to treat various wastewaters. Application of freezing technology to purify water is based on the principle that when water freezes, ice crystals grow of pure water and impurities are rejected from the ice structure and become concentrated in the unfrozen liquid. Without addition of any chemicals, contaminants in a large volume of dilute wastewater can be effectively removed by freeze concentration. Objectives of this study are: 1) literature review of occurrence of pharmaceutically active compounds, treatment technologies and analytical methods; and 2) experimental study: evaluate the potential of the freeze concentration process for the removal of selected pharmaceutically active compounds, the effect of initial concentration of drug residues, freezing temperature and degree of freezing on the removal efficiency of pharmaceutically active compounds. Five drugs aspirin, ibuprofen, gemfibrozil, metoprolol and sulfamethoxazole were selected to investigate the removal efficiency of freeze concentration. Gas chromatograph-mass spectrometry and total organic carbon were used to quantify the drug concentrations in water samples. After first freezing cycle, ibuprofen and gemfibrozil were concentrated 2-3 times compared to the feed water and the concentration factors reached 12 after second freezing cycle. The total removal efficiency of the selected pharmaceutically active compounds was about 80% after one stage freeze concentration. Results indicated that aspirin degraded during the treatment; therefore, the concentration of aspirin was difficult to measure. Analysis of sample total organic carbon concentration indicated that about 84% and 92% removal efficiency was achieved for ibuprofen and gemfibrozil one stage freeze concentration. Approximately 99% impurity removal efficiency and around 60% volume reduction was observed in refrozen ice obtained from the first freezing. This research results indicated freeze concentration was effective and not sensitive to the natural of target pharmaceutically active compounds in the feed water. In addition, the analytical methodology for the determination of drug residues in complex environmental matrices is still evolving and it may takes years before the universally accepted methods are developed. The gas chromatograph-mass spectrometry method used by many researchers requires complex sample preparation, which could influence the accuracy of the analysis

Highly efficient genome editing using oocyte-specific zcas9 transgenic zebrafish.Liu Y, Zhang C, Zhang Y, Lin S, Shi DL, Shao M

International audienceHighly efficient genome editing using oocyte-specific zcas9 transgenic zebrafish Since its first application to induce mutations in mammalian cells (Cong et al., 2013; Mali et al., 2013), CRISPR/Cas9 rapidly becomes a routine technique to perform genome editing in a variety of biological systems due to its facile, robust, and multiplexable features (Hwang et al., 2013; Guo et al., 2014; Wang et al., 2013). In every system, Cas9 and sgRNA should co-express to induce mutations. This is typically achieved by injection of the sgRNA mixed with Cas9 mRNA or protein into the fertilized eggs in zebrafish. As the in vivo translation of capped RNAs delay the presence of sufficient Cas9 protein, the mRNA injection produces more mosaic animals and shows relatively lower efficiency when compared to Cas9 protein injection (Burger et al., 2016). However, it is much more cost effective than using commercially available Cas9 protein, especially in the case of large-scale mutation screens. To further simplify this procedure, lower the cost and maintain an acceptable high genome editing efficiency in zebrafish, we set out to generate a transgenic line with stable and specific Cas9 expression in the egg. zpc (zp3b) promoter (zpc0.5) was reported to drive robust and specific GFP expression in the oocyte (Onichtchouk et al., 2003), we thus fused it with a zebrafish codon optimized cas9 (zcas9) followed by an SV40 3' UTR (Fig. 1A and File S1; Liu et al., 2014), and introduced this construct to zebrafish genome by Tol2 mediated transgenesis (Urasaki et al., 2006). To screen female F0 fish harboring this transgene, the F0 female founders were outcrossed with the wild-type male, the resulting eggs were injected with an sgRNA targeting slc45a2 (Moreno-Mateos et al., 2015), a gene essential for melanin synthesis, and assayed for their pigmentation phenotype. We found that the offspring of one founder showed a high proportion of pigmentation defect. Some of them exhibited a homozygous mutant like albino phenotype, suggesting a robust Cas9 expression in the egg and a very high efficient gene disruption. To examine the specificity of zcas9 expression in the transgenic line, the offspring (F1) of this F0 founder were raised to adulthood, and the ovaries of female F1 transgenic fish were dissected and subjected to in situ hybridization (ISH) employing the probe of zcas9. We found that the transcripts of zcas9 were specifically distributed in oocytes with a diameter of 40-200 µm, at around IB-II stages, while in WT embryos, no hybridization signals were detected (Fig. 1B, C). We did not detect zcas9 expression in stage IA oocytes or in larger ones after stage II. Accordingly, by RT-PCR, we also faile

Genotypic and Phenotypic Characterization of IncX3 Plasmid Carrying blaNDM-7 in Escherichia coli Sequence Type 167 Isolated From a Patient With Urinary Tract Infection

Infections due to New Delhi metallo-beta lactamase (NDM)-7-producing Escherichia coli are infrequent and sporadic. In this study, we report one case of recurrent urinary tract infection caused by blaNDM-7-producing E. coli belonging to phylogenetic group A, sequence type (ST) 167. In this study, we aimed to describe the genotype and phenotype of blaNDM-7-producing E. coli in China. The isolate exhibited resistance to β-lactam antimicrobials, trimethoprim-sulfamethoxazole, quinolones, and aminoglycosides. blaNDM-7 is located on a conjugative plasmid designated pJN05NDM-7 belonging to type IncX3. pJN05NDM-7 was fully sequenced and compared with all publicly available blaNDM-7-harboring plasmids. pJN05NDM-7 is almost identical to pKpN01-NDM7 and pKW53T, although the plasmids are geographically unrelated. The comparison of IncX3 plasmids harboring blaNDM in China showed high similarity, with genetic differences within insertion fragments. Notably, the differences in plasmids of animal and human origin were insignificant, because only one plasmid showed deletion inside the ISAba125 region compared with pJN05NDM7. Our study demonstrates that E. coli carrying IncX3 plasmids play an important role as a reservoir and in the spread of blaNDM. Further studies should be performed to control the dissemination of blaNDM among food animals

Fast Video Dehazing Using Per-Pixel Minimum Adjustment

To reduce the computational complexity and maintain the effect of video dehazing, a fast and accurate video dehazing method is presented. The preliminary transmission map is estimated by the minimum channel of each pixel. An adjustment parameter is designed to fix the transmission map to reduce color distortion in the sky area. We propose a new quad-tree method to estimate the atmospheric light. In video dehazing stage, we keep the atmospheric light unchanged in the same scene by a simple but efficient parameter, which describes the similarity of the interframe image content. By using this method, unexpected flickers are effectively eliminated. Experiments results show that the proposed algorithm greatly improved the efficiency of video dehazing and avoided halos and block effect

Genotypic and Phenotypic Characterization of Clinical Escherichia coli Sequence Type 405 Carrying IncN2 Plasmid Harboring blaNDM-1

We report a blaNDM-carrying ST405 Escherichia coli recovered from the abdominal fluid of a patient in Shandong, China. This strain belonged to the high-risk phylogenetic group D and carried the virulence genes, papG II, papG III, papC, and iroN. In addition to blaNDM-1, this isolate carried the quinolone resistance gene acc(6′)-Ib and extended-spectrum β-lactamase (ESBL) genes blaCTX-M-15 and blaCTX-M-14. blaNDM-1 was located on a 41 Kb IncN2 self-transmissible plasmid. The IncN2 plasmid named as pJN24NDM1 was fully sequenced and analyzed. Genome comparative analysis showed that IncN2 plasmids harboring carbapenem-resistance genes possessed conserved backbones and variable accessory regions. Phylogenetic analysis of 87 IncN plasmids based on orthologous genes indicated that 9 IncN2 plasmids fell into one phylogenetic clade, while 4 IncN3 plasmids were in two phylogenetic clades of the 74 IncN1 plasmids. The presence of IncN2 plasmids harboring blaNDM in the high-risk clone ST405 E. coli raises serious concerns for its potential of dissemination

Paleoseismic events and ages revealed by the Lianhuashan trench in the western section of the Tuyouqi of the Daqingshan piedmont fault

Daqingshan piedmont fault is located in the northern margin of Hetao basin and has been active strongly since the Late Quaternary. Previous researchers had conducted extensive research on the characteristics of paleoseismic in this area, but limited by the dating techniques and the fact that there were fewer data available on the same fault profile that can effectively constrain paleoseismic events, and fewer profiles that can reveal more paleoseismic events. This paper explores the excavation of an paleoseismic trench on the east side of Lianhuashan in the western section of Tuyouqi of the Daqingshan piedmont fault, using Optically Stimulated Luminescence data, and combineing with the age data of previous exploration trenches. By using the fault successive limit method, it is found that the western section of the Tuyouqi fault has experienced five paleoseismic events approximately 11500 years ago, with an average recurrence interval of 2260 years. The five paleoseismic events in this section of the fault, from new to old, are 1.28 to 1.42 ka, 3.41 to 3.60 ka, 4.08 to 5.01 ka, 8.26 to 9.32 ka, and 10.70 to 11.30 ka, respectively. The latest event of activity should be the earthquake of 849 AD. Meanwhile, the trench exploration revealed that the fault in this section exhibits a normal fault nature, with an inclination angle between 58 and 77 degrees. According to empirical formula, the potential seismic capacity of the Baotou section, the western section of Tuyouqi, and the western section of Tuzuoqi are around MW6.8～7.1, MW6.8～7.1 and MW7.1～7.2, respectively. The magnitude obtained by the empirical formula in this paper is relatively small, and there may be cascade rupture. In the later stage, it is necessary to conduct a comprehensive evaluation of the risk of the western section of Daqingshan piedmont fault combined with other means

Specificity for the correlation between the body surface and viscera in the pathological state of COPD: A prospective, controlled, and assessor-blinded trial

Background: The association between the body surface and viscera remains obscure, but a better understanding of the body surface-viscera correlation will maximize its diagnostic and therapeutic values in clinical practice. Therefore, this study aimed to investigate the specificity of body surface-viscera correlation in the pathological state.Methods: The study subjects included 40 participants with chronic obstructive pulmonary disease (COPD) in the COPD group and 40 age-matched healthy participants in the healthy control group. Laser Doppler flowmetry, infrared thermography, and functional near-infrared spectroscopy were respectively adopted to measure 1) the perfusion unit (PU), 2) temperature, and 3) regional oxygen saturation (rSO2) of four specific sites distributed in the heart and lung meridians. These three outcome measures reflected the microcirculatory, thermal, and metabolic characteristics, respectively.Results: Regarding the microcirculatory and thermal characteristics of the body surface, the PU and temperature of specific sites on the body surface [i.e., Taiyuan (LU9) and Chize (LU5) in the lung meridian] in the COPD group were significantly increased compared with healthy controls (p < 0.05), whereas PU and temperature of other sites in the heart meridian [i.e., Shenmen (HT7) and Shaohai (HT3)] did not change significantly (p > 0.05). Regarding the metabolic characteristics, rSO2 of specific sites in the lung meridian [i.e., Taiyuan (LU9) and Chize (LU5)] and Shaohai (HT3) of the heart meridian in the COPD group was significantly decreased compared with healthy controls (p < 0.01), whereas rSO2 of Shenmen (HT7) in the heart meridian did not change significantly (p > 0.05).Conclusion: In the disease state of COPD, the microcirculatory, thermal, and metabolic characteristics of specific sites on the body surface in the lung meridian generally manifest more significant changes than those in the heart meridian, thereby supporting relative specificity for the body surface-viscera correlation in the pathological state