152 research outputs found
Information Transfer in Quantum Mechanics
This paper deals with the most elementary information transmission in Quantum Mechanics. A simple quantum mechanical system under Coulomb-type potential is investigated. Like the classical case, a deep relation between the potential energy and the rate of information transfer is established for quantum-mechanical situation. The corresponding equation is presented. The article shows the circumstance for the free particle, too
Szerves aeroszol képződése felhőfolyamokban = Formation of organic aerosol in cloud processes
Kutatásaink során bizonyĂtottuk, hogy a felhĹ‘vĂzben a biomassza Ă©getĂ©s során kibocsátott vegyĂĽletekbĹ‘l polimerizáciĂłval fĂ©nyt elnyelĹ‘ humuszszerű anyag keletkezik. Vizsgáltuk ennek a folyamatnak a mechanizmusát, időállandĂłját Ă©s a keletkezett anyag kĂ©miai tulajdonságait is. Ezzel párhuzamosan a biomassza Ă©getĂ©sbĹ‘l származĂł aeroszolban megfigyelt, gömb alakĂş szerves rĂ©szecskĂ©k keletkezĂ©si mechanizmusát is valĂłszĂnűsĂtettĂĽk, amit összefĂĽggĂ©sbe hoztunk a fenti kĂ©miai reakciĂłval. E rĂ©szecskĂ©k abszorpciĂłs tulajdonságait kĂsĂ©rletileg is vizsgáltuk, Ă©s megállapĂtottuk, hogy a biomassza Ă©getĂ©sbĹ‘l származĂł aeroszolban a sugárzáselnyelĂ©s számottevĹ‘ hányadáért felelĹ‘s lehet. Kutatásaink során rĂ©szben nemzetközi egyĂĽttműködĂ©sben bizonyĂtottuk, hogy a termĂ©szetben a legnagyobb mennyisĂ©gben kibocsátott illĂ©kony szerves vegyĂĽletbĹ‘l, az izoprĂ©nbĹ‘l közvetve lehetsĂ©ges felhĹ‘folyamatokban aeroszol kĂ©pzĹ‘dĂ©s. A folyamat lĂ©gköri jelentĹ‘sĂ©gĂ©t egy egyszerűsĂtett lĂ©gköri modell segĂtsĂ©gĂ©vel vizsgáltuk, Ă©s megállapĂtottuk, hogy globális lĂ©ptĂ©kben jelentĹ‘s. A beszámolási idĹ‘szakban a pályázat tĂ©máját is Ă©rintĹ‘ monográfiát Ărtam Carbonaceous Aerosol cĂmmel, ami 2004-ben a Springer kiadĂłnál jelent meg. A könyv kĂĽlön alfejezetet szentel a felhĹ‘folyamatok lehetsĂ©ges szerepĂ©nek a másodlagos szerves aeroszol kĂ©pzĹ‘dĂ©sĂ©ben, ami a tudományterĂĽlet legĂşjabb eredmĂ©nyeit, nem kis rĂ©szben saját eredmĂ©nyeinket foglalja össze. | In our study it has been proved that volatile compounds released by biomass burning can polymerize into humic-like substances (HULIS) in cloud water. The mechanism and kinetics of these reactions, as well as the properties of the products have also been studied. It has been hypothesized that tar ball particles observed in biomass smoke may also be produced in such reactions. It has been found that these particles account for a significant fraction of absorption of shortwave radiation in biomass smoke. In another study, isoprene has been established as a possible precursor of secondary aerosol formation in cloud processes, and a model study has revealed that it is globally significant. My monograph titled Carbonaceous Aerosol was published in 2004 by Springer. In this book a separate sub-chapter is devoted to the role of cloud processes in secondary organic aerosol formation, partly based on the results of our recent studies in this field
Környezetvédelmi szempontból aktuális hőbomlási folyamatok termoanalitikai vizsgálata = Application of thermal analysis for studying thermal decomposition reactions possessing environmental interest
Műanyagok pirolitikus ĂşjrahasznosĂtásához Ă©s növĂ©nyi eredeti anyagok termikus hasznosĂtásához Ă©s analĂzisĂ©hez kapcsolĂłdtak a kutatásaink. A műszaki polimerek közĂĽl az ĂĽtĂ©sállĂł polisztirol Ă©s a polikarbonát Ă©gĂ©sgátlĂł adalĂ©kaibĂłl pirolĂziskor keletkezĹ‘ brĂłm-tartalmĂş vegyĂĽleteket azonosĂtottuk. MegállapĂtottuk, hogy a brĂłm megkötĂ©sĂ©re ammĂłniát lehet alkalmazni, mivel a keletkezĹ‘ ammĂłnium-bromid por könnyen elválaszthatĂł a többi termĂ©ktĹ‘l. Kimutattuk, hogy a szinergista adalĂ©k Sb2O3,valamint az Ă©gĂ©sgátlĂł ammĂłnium-polifoszfát (APP) egyaránt elĹ‘segĂti a polimerek elszenesedĂ©sĂ©t pirolĂzis során. MegállapĂtottuk, hogy az APP Ă©gĂ©sgátlĂłbĂłl felszabadul az ammĂłnia, Ă©s a visszamaradĂł polifoszforsav mĂłdosĂtja a polimerek bomlásmechanizmusát, amelyet tiszta polifoszforsav alkalmazásával igazoltunk. KörnyezetkĂmĂ©lĹ‘, enzimes eljárással fehĂ©rĂtett rostpĂ©pek vizsgálata során mĂłdszert dolgoztunk ki a nagyon kis mennyisĂ©gű maradĂ©k lignintartalom (<1%) meghatározására “in-situ” pirolĂzis-GC/MS segĂtsĂ©gĂ©vel. MegállapĂtottuk, hogy az enzimes biofehĂ©rĂtĂ©s Ă©s a rostpĂ©p előállĂtás során a ligninek funkciĂłs csoportjaiban kĂ©miai változások mennek vĂ©gbe, amelyek a további lignin eltávolĂtást (fehĂ©rĂtĂ©st) megnehezĂtik. KĂĽlönbözĹ‘ mezĹ‘gazdasági alapanyagok Ă©s hulladĂ©kok pirolitikus hasznosĂtásához vĂ©geztĂĽnk kĂsĂ©rleteket, amelynek során többfĂ©le szervetlen vegyĂĽlet Ă©s a szerves extrahálhatĂł anyagok hatását tisztáztuk. Ă–sszefĂĽggĂ©st állapĂtottunk meg a hĹ‘bomlási paramĂ©terek Ă©s az alkáliion-tartalom között. | This project has been related to the pyrolytic recycling of plastics and to the thermal utilization and analysis of biomass materials. Two technical polimers, high-impact polystyrene and polycarbonate have been studied and the brominated compounds have been identified among the pyrolysis products. We established that ammonia can be applied for trapping the bromine content because the ammonium-bromide powder formed can be easily separated from the other products.We demonstrated that both the synergyst Sb2O3 and the flame-retardant ammoniumpolyphosphate (APP) enhance the charring reactions during pyrolysis. We concluded that APP releases NH3 and the residual polyphosphoric acid modifies the decomposition mechanism of polymers, which was proved by the addition of pure polyphosphoric acid. Studying the pulps bleached by environmental friendly enzymatic process we determined the residual lignin content (<1%) by in-situ pyrolysis-GC/MS. We established that chemical reactions occurred in the functional groups of lignins during enzymatic biobleaching and pulping, which renders the further lignin elimination (bleaching) more difficult. We carried out experiments for the thermal utilization of various agricultural products and waste materials. We clarified the effect of various inorganic compounds and extractives on the thermal decomposition. We obtained correlations between the decomposition parameters and the alkali ion content
AdalĂ©kanyagok hatása a hulladĂ©khasznosĂtás szempontjábĂłl fontos hĹ‘bomlási folyamatokban = Effect of additives on the thermal decomposition reactions occurring in waste utilization
A kutatás cĂ©lja az volt, hogy felderĂtsĂĽk az adalĂ©kanyagok hatását műanyag- Ă©s fahulladĂ©kok termikus feldolgozása szempontjábĂłl fontos kĂ©miai folyamatokban. MegállapĂtottuk, hogy a korom a polimerek elsĹ‘dleges bomlási reakciĂłit befolyásolja, Ă©s hatása fĂĽgg a polimer bomlásmechanizmusátĂłl valamint a korom illĂłanyagtartalmátĂłl. Egy reakciĂłmechanizmust állĂtottunk fel, amely szerint a korom hĹ‘bomlástermĂ©kei kĂ©pesek inicializálni a poliizobutilĂ©n Ă©s polipropilĂ©n hĹ‘bomlását. BrĂłmtartalmĂş Ă©gĂ©sgátlĂłkat Ă©s antimon-trioxid szinergista adalĂ©kot tartalmazĂł ĂĽtĂ©sállĂł polisztirol hĹ‘bomlását vizsgálva megállapĂtottuk, hogy antimon-trioxid jelenlĂ©tĂ©ben kĂ©tlĂ©pcsĹ‘s bomlási mechanizmus alakul ki. A polisztirol, az Sb2O3 Ă©s a brĂłmtartalmĂş Ă©gĂ©sgátlĂłk kölcsönhatásának magyarázatára egy gyökös bomlási mechanizmust Ărtunk fel. MegállapĂtottuk, hogy a fában Ă©s a kĂ©regben levĹ‘ cellulĂłz bomláshĹ‘mĂ©rsĂ©kletĂ©nek kĂĽlönbsĂ©gĂ©t a szervetlen ionok mennyisĂ©gĂ©nek eltĂ©rĂ©se okozza. A bomlási sebessĂ©get pedig a polimerösszetĂ©tel Ă©s a szervetlen anyag mennyisĂ©ge egyĂĽttesen határozza meg. MegállapĂtottuk, hogy az extraktumok szĂ©les hĹ‘mĂ©rsĂ©klettartományban bomlanak, ezáltal befolyásolják a fa hĹ‘bomlását. MĂłdszert dolgoztunk ki mezopĂłrusos alumino-szilikát (Al-MCM-41) Ă©s szilikagĂ©l (SBA-15) tĂpusĂş katalizátorok gyors tesztelĂ©sĂ©re, amelyeket bioolajok katalitikus átalakĂtására alkalmaztunk. A rostpĂ©pek lignintartalmát Ă©s a lignin kĂ©miai összetĂ©telĂ©ben bekövetkezett változásokat pirolĂzissel határoztuk meg. | The objectives of this project were to clarify the effect of additives on the chemical reactions during the thermal treatments of plastics and wood wastes. We concluded that carbon black affects the primary decomposition reactions of polymers; and the effect depends on the decomposition mechanisms of the polymers and the volatile matter content of the carbon black. We suggested a reaction mechanism: the volatile products of carbon black initiate the decomposition of polypropylene and polyisobutylene. We studied the thermal decomposition of high-impact polystyrene containing brominated flame retardants and antimony trioxide synergist, and found two-step decomposition mechanisms in the presence of Sb2O3. The interaction of polystyrene, Sb2O3 and brominated flame-retardants was explained by radical decomposition mechanisms. We concluded that the different inorganic material content leads to the different decomposition temperature of cellulose in wood and bark. However, the decomposition rate is determined by both the composition of polymeric constituents and the amount of inorganic materials. We established that the extractive materials decompose in a wide temperature range, thus influencing the thermal decomposition of wood. We tested various mesopore aluminosilicate (Al-MCM-41) and silica (SBA-15) catalysts for the catalytic upgrading of bio-oils of wood. The lignin content and the structural changes of lignin in pulps were determined by pyrolytic methods
Pyrolysis of wood – PVC mixtures. Formation of chloromethane from lignocellulosic materials in the presence of PVC
Thermal decomposition of polyvinylchloride (PVC) – wood and wood component mixtures were examined under slow and fast heating by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetry/mass spectrometry(TG/MS) techniques in order to clarify the chemical interaction of biomass materials and PVC during thermal decomposition. A hardwood and a softwood (beech and pine), their lignin and two types of cellulose (Avicel and Whatman) were chosen as natural polymer components. Comparing the gaseous and liquid pyrolysis products of pure samples to those of mixtures it was found that considerably lower amount of several reactive compounds have been produced when the biomass sample was mixed with PVC. On the other hand significant amount of chloromethane appeared in the pyrolysate of wood and lignin samples mixed with PVC under fast and slow pyrolysis conditions as well, but only in traces of chlorinated organic compounds were detected from cellulose mixtures. It was concluded that the methoxy groups at phenolic rings in lignin are the methyl source of chloromethane formation, and this reaction consumed most of the HCl evolved from PVC
KörnyezetszennyezĹ‘ komponensek eltávolĂtása műanyaghulladĂ©kok pirolĂzistermĂ©kĂ©bĹ‘l = Elimination of polluting components from pyrolysis oils of plastics wastes
A pályázat cĂ©ljának megfelelĹ‘en műanyaghulladĂ©kokbĂłl nyert pirolĂzisolajokat mĂłdosĂtottunk szilárd fázisĂş katalizátorok segĂtsĂ©gĂ©vel a nitrogĂ©n- Ă©s a halogĂ©ntartalom csökkentĂ©se Ă©rdekĂ©ben. MegállapĂtottuk, hogy az Y Ă©s Ăź zeolitok többnyire megváltoztatják a polimerek hĹ‘bomlástermĂ©k vegyĂĽleteit, magát a hĹ‘bomlás reakciĂłját azonban kevĂ©ssĂ© befolyásolják. GyengĂ©n savas zeolit katalizátorágyon a pirolĂzistermĂ©k molekulák heteroatomot (nitrogĂ©nt Ă©s oxigĂ©nt) tartalmazĂł csoportjai leszakadnak, Ăgy a pirolizátum nitrogĂ©ntartalma a gázfázisba kerĂĽl, mĂg a szĂ©nhidrogĂ©n szegmensek egy- Ă©s kĂ©tgyűrűs aromás szĂ©nhidrogĂ©n vegyĂĽletekkĂ© alakulnak. A nátrium-zeolit kisebb molekulákra tördeli, Ă©s gyűrűbe zárja a hĹ‘bomlás termĂ©keit, de nem bontja a szĂ©n-nitrogĂ©n kötĂ©seket; Ăgy ez a katalizátor alig csökkenti a pirolĂzisolaj nitrogĂ©ntartalmát. A foszfortartalmĂş gyengĂ©n savas szervetlen Ă©gĂ©sgátlĂłk jelentĹ‘s hatással vannak a polimerek hĹ‘bomlási folyamataira Ă©s azok termĂ©keire, azonban a pirolĂzisolaj nitrogĂ©ntartalmát nem befolyásolják. A nátriumionos Y Ă©s Ăź zeolitok általában alkalmasak a klĂłr- Ă©s brĂłmtartalmĂş pirolĂzisolajok halogĂ©ntartalmának mĂ©rsĂ©klĂ©sĂ©re, de halogĂ©nmentesĂtĹ‘ aktivitásuk jelentĹ‘sen eltĂ©rĹ‘ a kĂĽlönbözĹ‘ tĂpusĂş szerves klĂłr- Ă©s brĂłmvegyĂĽletek esetĂ©ben. Tanulmányoztuk a deaktiválĂłdott zeolitok regenerálhatĂłságát is. A katalitikus aktivitás elvesztĂ©sĂ©t okozĂł szenes lerakĂłdás minĹ‘sĂ©ge eltĂ©rĹ‘nek bizonyult a protonos Ă©s a nátriumion tartalmĂş zeolitoknál. | In accordance with the goals of the project pyrolysis oils of plastics waste have been converted over solid catalysts in order to decrease their nitrogen and halogen content. Our observations showed that the thermal decomposition reactions of polymers are hardly altered, but their products are mostly modified by Y and Ăź zeolite. The heteroatom (N and O) containing groups of the pyrolysis product molecules are cleaved over zeolites of weak acidity, thus the nitrogen content of the pyrolysate is moved to the gas phase, while the hydrocarbon parts are converted to aromatic hydrocarbons of one and two rings. Over sodium-zeolites the pyrolysis product molecules are either split at C-C bonds or cyclised. But the C-N bonds are not cleaved, so the nitrogen content of the pyrolysis oil has hardly decreased over these zeolites. The inorganic phosphor containing flame retardants of weak acidity proved to influence the thermal decomposition process of the polymers, however, the nitrogen content of the pyrolysis oil has not been changed by them. Our experiments revealed that Na-Y and Na-Ăź zeolite can be applied for dehalogenating pyrolysis oils of chlorine and bromine containing polymers, nevertheless their catalytic activity considerably differ for various types of organic chloro-and bromo-compounds. The regeneration of the deactivated zeolites has been also studied. The quality of the deposited coke proved to be different on the surface of protonated and sodium forms of zeolite
Bioactivity-Guided Investigation of the Anti-Inflammatory Activity of Hippophae rhamnoides Fruits
AbstractAccording to modern ethnobotanical records, the fruit of Hippophae rhamnoides is effective in the treatment of different allergic symptoms. In order to obtain pharmacological evidence for this observation, the fruit was investigated for anti-inflammatory activity using in vivo animal models. Aqueous and 70% MeOH extracts were tested in 48/80-induced rat paw edema assay after oral administration, and it was found that the 70% MeOH extract (500 mg/kg) reduced significantly edema volume (0.660 ± 0.082 mL vs. control 0.935 ± 0.041 mL). Extracts of different parts of the fruit (pulp, peel, seed) were investigated in the same assay, and the peel extract was shown to exhibit maximum edema-reducing effect (0.470 ± 0.124 mL vs. control 0.920 ± 0.111 mL). This extract was used to elucidate the mode of action. Different inflammation inducers (serotonin, histamine, dextran, bradykinin, and carrageenan) were applied in the rat paw model, but the extract inhibited only the compound 48/80 elicited inflammation. The active extract was then fractionated by solvent-solvent partitioning and chromatographic methods with the guidance of the 48/80-induced anti-inflammatory assay, and the main compounds responsible for the activity were identified as ursolic acid and oleanolic acid. Our data suggest that the activity is most probably based on a membrane stabilizing effect caused by the inhibition of degranulation of mast cells. Moreover, previously unknown 2,5-bis-aryl-3,4-dimethyltetrahydrofuran lignans, nectandrin B, fragransin A2, and saucernetindiol were isolated and identified from H. rhamnoides for the first time.</jats:p
Chemical transformations in organic aerosol from biomass burning
International audienceFine aerosol particles were collected separately during daytime and nighttime at a tropical pasture site in RondĂ´nia, Brazil, during the burning and dry-to-wet transition period in 2002. Total carbon (TC) and water-soluble organic carbon (WSOC) were measured by evolved gas analysis (EGA). Based on the thermochemical properties of the fine aerosol, the relative amounts of the low and higher molecular weight compounds were estimated. It was found that the thermally refractory (possibly higher molecular weight) compounds dominated the TC composition. Their contribution to TC was higher in the daytime samples than in the nighttime ones. The relative share of WSOC also showed a statistically significant diel variation and so did its refractory fraction. Anhydrosugars and phenolic acids were determined by GC-MS and their diel variation was studied. Based on the decrease of their relative concentrations between the biomass burning and transition periods and their distinctly different diel variations, we suggest that the phenolic acids may undergo chemical transformations in the aerosol phase, possibly towards more refractory compounds (humic-like substances, HULIS), as has been suggested previously. These conclusions are supported by the results of the thermally assisted hydrolysis and methylation gas chromatography-mass spectrometry of the same filter samples
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