Fugitive emissions in Moravian-Silesian Region

Import 22/07/2015Predložená práca sa zaoberá fugitívnymi emisiami na území priemyselnej aglomerácie Ostravska. Fugitívny prach predstavuje hlavnú časť atmosférických aerosólov, zvýšená pozornosť je mu venovaná kvôli významným dopadom na zmenu klímy, kvalitu ovzdušia a zdravie ľudí a ekosystémov. Hlavná časť práce je venovaná štúdiu vertikálnej distribúcie PM1 vo výške až 500 m n. m., ktorá bola sledovaná vo vybraných lokalitách Ostravy v jarnom a letnom období 2014, za použitia metódy merania balónom. Pozornosť bola venovaná závislosti koncentrácie PM1 na výške a meteorologických podmienkach. Ďalej bolo zisťované rozloženie organických látok vo vertikálnych profiloch atmosféry v najzaťaženejších miestach Ostravy použitím metódy Py-GC/MS a pomocou matematických metód boli identifikované príspevky zdrojov znečistenia.This thesis deals with the topic of fugitive emissions in the industrial agglomeration of Ostrava region. Fugitive dust is a major part of atmospheric aerosols, increased attention is given to it due to its significant impact on climate change, air quality and human health, and ecosystems. The main part is focused on the study of the vertical distribution of PM1 of up to 500 m a. s. l. which was monitored at selected locations during spring and summer seasons of 2014 using the balloon measuring method. Attention was given to influence of meteorological parameters on PM1 concentrations. Furthermore, distribution of organic matter in the vertical profiles of the atmosphere in the most exposed places was studied using the Py-GC/MS and, using the mathematical methods, contributions of the sources of pollution were identified.Prezenční546 - Institut environmentálního inženýrstvívýborn

<i>In Situ</i> TEM on the Reversibility of Nanosized Sn Anodes during the Electrochemical Reaction

Excellent reversibility is crucial for the storage capacity and the cycle life of anode materials in high-performance lithium ion batteries, which has not been observed in alloy-type materials such as Si or Ge. <i>In situ</i> transmission electron microscopy reveals a sequential phase transformation in individual Sn nanowires during Li insertion, which is in a reverse order during Li extraction. Both the bright field image and the electron diffraction show a two-step reversible crystalline–crystalline phase transformation. It is noted that the crystalline tin has a more open lattice to readily accommodate Li up to the Li₂Sn₅ phase while retaining the crystallinity, which distinguishes Sn from its metalloid counterparts. The connected interstices along [001] inside lattice form a helix pipe for fast Li diffusion, indicating the openness of the Sn lattice. The <i>ab initio</i> simulations reveal facile Li diffusion along [001] with a low migration barrier of 0.014 eV. No phase boundary is visible in this step. In the second step, the Li_<i>x</i>Sn_<i>y</i> phases, including the Li₂₂Sn₅ phase, nucleated with grain refinement and enormous volume expansion. The broaden phase boundary indicates that the further alloying is rate-limited not by the diffusion of Li but by the interfacial conversion reaction. The pulverization occurs during delithiation by agglomeration of regular-shape voids, showing a different mechanism from the cracking-dominated fracture in Si. These results elucidate the structural evolution and the phase transformation during the electrochemical cycling, which sheds light on engineering Sn anode materials

Atomic Bonding between Metal and Graphene

To understand structural and chemical properties of metal–graphene composites, it is crucial to unveil the chemical bonding along the interface. We provide direct experimental evidence of atomic bonding between typical metal nano structures and graphene, agreeing well with density functional theory studies. Single Cr atoms are located in the valleys of a zigzag edge, and few-atom ensembles preferentially form atomic chains by self-assembly. Low migration barriers lead to rich dynamics of metal atoms and clusters under electron irradiation. We demonstrate no electron-instigated interaction between Cr clusters and pristine graphene, though Cr has been reported to be highly reactive to graphene. The metal-mediated etching is a dynamic effect between metal clusters and pre-existing defects. The resolved atomic configurations of typical nano metal structures on graphene offer insight into modeling and simulations on properties of metal-decorated graphene for both catalysis and future carbon-based electronics

Atomic Bonding between Metal and Graphene

To understand structural and chemical properties of metal–graphene composites, it is crucial to unveil the chemical bonding along the interface. We provide direct experimental evidence of atomic bonding between typical metal nano structures and graphene, agreeing well with density functional theory studies. Single Cr atoms are located in the valleys of a zigzag edge, and few-atom ensembles preferentially form atomic chains by self-assembly. Low migration barriers lead to rich dynamics of metal atoms and clusters under electron irradiation. We demonstrate no electron-instigated interaction between Cr clusters and pristine graphene, though Cr has been reported to be highly reactive to graphene. The metal-mediated etching is a dynamic effect between metal clusters and pre-existing defects. The resolved atomic configurations of typical nano metal structures on graphene offer insight into modeling and simulations on properties of metal-decorated graphene for both catalysis and future carbon-based electronics

Atomic Bonding between Metal and Graphene

To understand structural and chemical properties of metal–graphene composites, it is crucial to unveil the chemical bonding along the interface. We provide direct experimental evidence of atomic bonding between typical metal nano structures and graphene, agreeing well with density functional theory studies. Single Cr atoms are located in the valleys of a zigzag edge, and few-atom ensembles preferentially form atomic chains by self-assembly. Low migration barriers lead to rich dynamics of metal atoms and clusters under electron irradiation. We demonstrate no electron-instigated interaction between Cr clusters and pristine graphene, though Cr has been reported to be highly reactive to graphene. The metal-mediated etching is a dynamic effect between metal clusters and pre-existing defects. The resolved atomic configurations of typical nano metal structures on graphene offer insight into modeling and simulations on properties of metal-decorated graphene for both catalysis and future carbon-based electronics

H₂O₂ sensitivity in <i>D. radiodurans</i> and <i>E. coli</i> treated with DNA fragments or dNMPs.

<p>(A) Sensitivity of <i>D. radiodurans</i> to H₂O₂ after the addition of 3.6 mg/ml DNA fragments or dNMPs. (B) Sensitivity of <i>E. coli</i> K-12 to H₂O₂ after the addition of 3.6 mg/ml DNA fragments or dNMPs. Each data point represents the mean±SD of three replicates. R1, <i>D. radiodurans</i> wild type strain.</p

H₂O₂ sensitivity in <i>D. radiodurans</i> treated with dAMP, dTMP, dCMP or dGMP.

<p>Sensitivity of <i>D. radiodurans</i> to 50 mM H₂O₂ with the addition of DNA fragments (3.6 mg/ml), dNMPs, dAMP, dTMP, dCMP or dGMP (10 mM for each). Each data point represents the mean±SD of three replicates. R1, <i>D. radiodurans</i> wild type strain.</p

Addition of extracellular dGMP increases the activity of KatA in <i>D. radiodurans</i>.

<p>(A) Extracellular dGMP (2.5 mM) increased the activity of KatA, but not KatB. (B) Extracellular dGMP (2.5 mM) had no effect on the activity of SOD. (C) and (D) Quantification of the intensity of bands was performed using ImageJ. Each sample contains 80 µg of total protein. Values are the mean ± standard deviation of three independent measurements. R1, <i>D. radiodurans</i> wild type strain; KatA, catalase A; KatB, catalase B.</p

Changes in Birth Weight between 2002 and 2012 in Guangzhou, China

<div><p>Background</p><p>Recent surveillance data suggest that mean birth weight has begun to decline in several developed countries. The aim of this study is to examine the changes in birth weight among singleton live births from 2002 to 2012 in Guangzhou, one of the most rapidly developed cities in China.</p><p>Methods</p><p>We used data from the Guangzhou Perinatal Health Care and Delivery Surveillance System for 34108 and 54575 singleton live births with 28–41 weeks of gestation, who were born to local mothers, in 2002 and 2012, respectively. The trends in birth weight, small (SGA) and large (LGA) for gestational age and gestational length were explored in the overall population and gestational age subgroups.</p><p>Results</p><p>The mean birth weight decreased from 3162 g in 2002 to 3137 g in 2012 (crude mean difference, −25 g; 95% CI, −30 to −19). The adjusted change in mean birth weight appeared to be slight (−6 g from 2002 to 2012) after controlling for maternal age, gestational age, educational level, parity, newborn's gender and delivery mode. The percentages of SGA and LGA in 2012 were 0.6% and 1.5% lower than those in 2002, respectively. The mean gestational age dropped from 39.2 weeks in 2002 to 38.9 weeks in 2012. In the stratified analysis, we observed the changes in birth weight differed among gestational age groups. The mean birth weight decreased among very preterm births (28–31 weeks), while remained relatively stable among other gestational age subcategories.</p><p>Conclusions</p><p>Among local population in Guangzhou from 2002 to 2012, birth weight appeared to slightly decrease. The percentage of SGA and LGA also simultaneously dropped, indicating that newborns might gain a healthier weight for gestational age.</p></div

Maternal and newborn characteristics among singleton live births in 2002 and 2012.

<p>Data are expressed as mean ± standard deviation or n(%).</p><p>Maternal and newborn characteristics among singleton live births in 2002 and 2012.</p