256 research outputs found
2D correlation spectroscopy of atmospheric reactions, measured with an aerosol flow-reactor in the mid infrared spectral region
No full textMechanistic details on atmospheric reactions of reactive halogen species (RHS) with organic compounds are still poorly known. The reaction of RHS with typical precursors of secondary organic aerosol (SOA) like terpenes forms so-called halogen-induced organic aerosol (XOA). On the other hand, RHS are also able to change the composition of functional groups, e.g. to initiate the decarboxylation of carboxylic acids1. A detailed understanding of these reactions is important to understand and model the global impact of the reactivity of RHS with organic species on radiativ forcing, global warming and various other physico-chemical properties of the troposphere.
The present study uses a 50 cm aerosol flow-reactor2, equipped with a solar simulator to investigate the time-resolved evolution and transformation of vibrational features in the mid-infrared region. The aerosol flow-reactor is coupled to a home-made multi-reflection cell3, integrated into a Bruker IFS 113v FTIR spectrometer. The reactor is operated with an inlet feed (organic compound) and a surrounding feed (reactive halogen species). The moveable inlet of the flow reactor allows us to vary reaction times between a few seconds and up to about 3 minutes. Saturated vapours of different SOA precursors and carboxylic acids were fed into the flow reactor and mixed with molecular chlorine as a source for RHS.
Synchronous and asynchronous 2D correlation spectroscopy4,5 was applied to the time-resolved dataset to obtain a mechanistic picture. Single reaction steps of XOA formation and decarboxylation of carboxylic acids could be clarified.
1. J. Ofner, N. Balzer, J. Buxmann, H. Grothe, P. Schmitt-Kopplin, U. Platt, and C. Zetzsch, Atmos. Chem. Phys., 2012, 12, 5787-5806.
2. J. Ofner, H.-U. Krüger, and C. Zetzsch, Zeitschrift für Physikalische Chemie, 2010, 224, 1171-1183.
3. J. Ofner, H.-U. Krüger, and C. Zetzsch, Applied Optics, 2010, 49, 5001.
4. I. Noda, A. Dowrey, and C. Marcott, Appl. Spectrosc, 2000, 54, 236A-248A.
5. B. Muik, B. Lendl, A. Molina-Diaz, M. Valcarcel, and M. J. Ayora-Cañada, Analytica chimica acta, 2007, 593, 54-67
Time-resolved FTIR spectroscopy of halogen-induced organic aerosol formation using an aerosol flow-reactor and 2D correlation spectroscopy
No full textReactive halogen species (RHS) are released to the atmosphere from various sources like photo-activated sea-salt aerosol1 and salt lakes2. Recent studies3,4 indicate that RHS are able to interact with precursors of secondary organic aerosol (SOA) similar to common atmospheric oxidizing gases like OH radicals and ozone. The reaction of RHS with SOA precursors like terpenes forms so-called halogen-induced organic aerosol (XOA). Due to the high reactivity, aerosol formation, initiated by RHS, seems to take place on a very short time-scale. The combination of flow reactors with FTIR spectroscopy provides access to time-resolved spectroscopy at temporal resolutions of several seconds, allowing direct spectroscopy of the formation process of XOA.
The present study uses a 50 cm aerosol flow-reactor5, equipped with a solar simulator, to investigate the time-resolved evolution and transformation of vibrational features in the mid-infrared region during the chlorine-induced formation of XOA. The aerosol flow-reactor is coupled to a Bruker IFS 113v FTIR spectrometer, using a home-made multi-reflection cell. The formation process of XOA from several organic precursor (α-pinene, limonene, Δ3-carene and p-xylene) was analyzed using 2D correlation spectroscopy6,7.
Using this setup and 2D correlation spectroscopy, the formation of halogen-induced organic aerosol could be monitored with a high temporal resolution. XOA formation is characterized by hydrogen-atom abstraction, carbon-chlorine bond formation and the formation of carboxylic acids. Several changes of the entire structure of the organic precursor, caused by the reaction of RHS, are visible. Hence, a more detailed understanding of halogen-induced organic aerosol formation and its relation to common SOA is provided.
1. B. J. Finlayson-Pitts, Chemical reviews, 2003, 103, 4801-22.
2. J. Buxmann, N. Balzer, S. Bleicher, U. Platt, and C. Zetzsch, Int. J. Chem. Kinet., 2012, 44, 312-326.
3. X. Cai and R. J. Griffin, Journal of Geophysical Research, 2006, 111, D14206.
4. J. Ofner, N. Balzer, J. Buxmann, H. Grothe, P. Schmitt-Kopplin, U. Platt, and C. Zetzsch, Atmos. Chem. Phys., 2012, 12, 5787-5806.
5. J. Ofner, H.-U. Krüger, and C. Zetzsch, Zeitschrift für Physikalische Chemie, 2010, 224, 1171-1183.
6. I. Noda, A. Dowrey, and C. Marcott, Appl. Spectrosc, 2000, 54, 236A-248A.
7. B. Muik, B. Lendl, A. Molina-Diaz, M. Valcarcel, and M. J. Ayora-Cañada, Analytica chimica acta, 2007, 593, 54-67
Lying and walking surfaces for cattle, pigs and poultry and their impact on health, behaviour and performance
No full textAppropriate housing that promotes excellent health and high welfare for different livestock species is an essential aspect of sustainable animal production. The appropriate design of livestock buildings is a fast changing and ever improving professional endeavour. This book is set out to review the 'current best practice management' in relation to all key design elements of livestock buildings. It is important to manage these buildings correctly to generate environmental conditions that will enhance the health and welfare of livestock, the health of farm workers and people living near farming operations.
'Livestock housing' is written for all those who are involved in managing the health and welfare conditions of housed livestock on commercial farms, including farm workers, animal scientists, veterinarians, agricultural engineers and of course students. Contributions have been solicited from highly respected specialists from around the world. All key areas of housing management are reviewed, including feeding, watering, ventilation and waste management systems. Furthermore, issues such as the control of emissions, role of bedding, maintenance of hygiene, the management of thermal and aerial environment as well as the use of modern technological tools in the service of livestock management are discussed. This book provides a unique forum for leading international experts to convey up-to-date information to professionals involved in modern animal production
Berufliche Weiterbildung in europäischer Perspektive
No full textBerufliche Weiterbildung ist selten Gegenstand bildungsökonomischer Analysen gewesen. Die Autoren des vorliegenden Bandes widmen sich dieser Thematik in europäischer Perspektive. -- J. Münch stellt die Frage, ob von einem 'europäischen System' der Weiterbildung die Rede sein könne. Er analysiert die Weiterbildungsstrukturen verschiedener europäischer Länder sowie deren Finanzierungsmuster und fragt nach den Kostenstrukturen der beruflichen Weiterbildung. H.-J. Bodenhöfer und F. Ofner untersuchen, welche Optionen jungen Österreichern im Anschluß an eine erfolgreiche Lehre offen stehen und welcher Stellenwert beruflicher Weiterbildung zukommt. Sie fragen dabei nach den Wechselwirkungen zwischen Lebenssituation, Motivation und Weiterbildungserfolg unter den Jugendlichen. U. Backes-Gellner beobachtet, daß evidente Differenzen in den Berufsausbildungsarrangements der europäischen Länder bestehen und leitet daraus die Frage nach Konvergenztendenzen zwischen den Berufsausbildungssystemen der europäischen Länder ab. Dabei sucht die Autorin nach betrieblichen Bildungsstrategien, die für Konvergenz- oder Divergenztendenzen verantwortlich sein könnten. R. v. Weizsäcker nimmt das fundamentale Problem des Zusammenhangs von Chancengleichheit, Statusmobilität und öffentlichen Bildungsinvestitionen in den Blick. Ihm geht es vorrangig um die Frage, ob hinter stabilen Einkommensverteilungsrelationen ein hohes oder niedriges Maß an individueller und sozialer Mobilität steht, d.h. ob das Chancengleichheitsziel mit dem Mobilitätsziel kompatibel ist. Alle vier Beiträge gelangen zu interessanten und z. T. überraschenden Ergebnisse
Historisch-demographische Mitteilungen / Review of Historical Demography
No full textInhalt
Mitteilungen
Eliška Caňova - Pavla Horska: Zusammenarbeit der tschechoslowakischen Archivare auf dem Gebiet der Demographie
Dr. Karl Obermann: Zur Sozialstruktur der Landbevölkerung im Königreich Hannover anhand von Statistiken und Wählerverzeichnissen (1848)
László Mészáros: Bevölkerungstatistische, demographische, soziale und ethnische Verhältnisse der Hasstädte der Ofner Sandschaks (1546-1562)
Dr. Lajos Thirring: Über Probleme der bevölkerungsdynamischen Analyse von Volkszählungsergebnissen
Dr. Jószef Kovacsics: Unterricht der Statistik und der Demographie an den Universitäten (1777-1977)
Buchbesprechunge
Mechanisms Of Heterogeneous Reactions On Soot Surfaces
No full textSoot emissions of diesel engines are suspected of causing negative health effects.
Possible ways to reduce these emissions are particle filters, from which the particles are
removed by strong oxidants such as NO2 or O2. The interactions of these oxidizers with
the carbonaceous surface and a possible promoting effect of H2O have been studied in
recent publications focussing mainly on kinetics. However, mechanistic details of these
reactions are rarely reported.
Diffuse-Reflectance-Infrared-Fourier-Transform-Spectroscopy (DRIFTS) provides
detailed information about functional groups on the soot surface and have been recorded
before and after the respective reaction treatment with the above-mentioned oxidizing
gases. DRIFTS-Spectra have been recorded at high vacuum and at temperatures up to
723 K. Temperature-Programmed-Desorption-Mass-Spectroscopy (TPD-MS) pyrolyses
the functional surface groups and allows a subsequent detection of the fragments by a
quadrupole mass spectrometer (QMS) as a function of the decomposition temperature
(up to 1173 K). Temperature-Programmed-Oxidation-Mass-Spectroscopy (TPO-MS)
indicates the same changes but measures continuously during the oxidation process.
Combination of DRIFTS, TPD, and TPO supplies the understanding of the interaction
of NO2 with the soot surface [1,2,3] on a molecular level and consequently resolves the
mechanisms of soot surface oxidation by NO2 and its site-effects with oxygen and
water, i.e. the cooperation effect [4]. Additionally, pre-existing functional groups on the
soot surface and their changes as a function of temperature und oxidation could be
assigned.
[1] Muckenhuber H., Grothe H., The heterogenous reaction between soot and NO2 at elevated
temperature, Carbon, 2006, 44, 546
[2] Muckenhuber H., Grothe H., The reaction between soot and NO2 investigation of functional
groups using TPD-MS, Topics in Catalysis, 2004, 30/31, 287
[3] Muckenhuber H., Grothe H., A DRIFTS study of the heterogenous reaction of NO2 with
carbonaceous materials at elevated temperature, Carbon, 2007, 45, 321
[4] Ofner J., Grothe H., A mechanistic study of the cooperative effect of NO2 and O2 on the soot
surfaces, Asian Chemistry Letters, 2007, 11, 1&2, 57-6
Using HCAHPS data to model correlates of medication understanding at hospital discharge
No full textRebecca J Bartlett Ellis,1 Karen L Werskey,2 Rachel M Stangland,2 Susan Ofner,1,3 Giorgos Bakoyannis1,3 1Indiana University School of Nursing, Indianapolis, IN, 2Schneck Medical Center, Seymour, IN, 3Department of Biostatistics, School of Medicine, Indiana University, Indianapolis, IN, USA Background: Hospitals are challenged to improve hospital transitions to home and are held accountable through public reporting.Design: This cross-sectional study used patients’ self-reported experience data from the publicly reported Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey to describe correlates of medication understanding at hospital discharge, using data collected from adult patients discharged from one Midwestern community hospital (N=154).Results: The final logistic regression model included four correlates of medication understanding: 1) nurse always communicates well, 2) physician always communicates well, 3) new prescriptions during hospital stay, and 4) very good or better mental health, and these classified 72.6% of the cases. Significant correlates of the patient strongly agreeing that they understood discharge medications were the “nurse always communicates well” (odds ratio =3.10, 95% confidence interval: 1.25, 7.66) and “very good or better self-perceived mental health” (odds ratio =2.17, 95% confidence interval: 1.02, 4.64).Conclusion: HCAHPS data can be used to model correlates of medication understanding, which are then useful for evaluating intervention effects following quality improvement. Keywords: medication, nurse communication, provider communication, hospital quality, nurse, nursing, physician, patient experience, patient satisfactio
Spectroscopy, microscopy and diffraction experiments devoted to ice clouds
No full textWater ice and nitric acid hydrates exhibit very different particle morphologies, which have an enormous impact on its ability to scatter and reflect light. This has an effect not only on the detection of ice particles by satellite instruments or ground-based optical remote sensing but also interferes with earth´s radiation balance. Since most morphological investigations in the atmosphere are hampered due to an interference of the microscopic technique to the ice particles, one is dependent on laboratory model experiments. In the past, a scanning electron microscope required a sufficient vacuum in the sample chamber in order to prevent a diversion of the electron beam. Modern environmental electron microscopy uses an imaging gas (water or nitrogen), which connects different advantages and prevents several handicaps. Firstly, the imaging gas works as secondary-emission multiplier. Secondly, the gas discharges the sample surface regularly and makes insulators accessible to SEM. Thirdly, a mixture of water and nitrogen prevents dehydration of the sample. Here, we present ESEM pictures of nitric acid hydrates and water ices. These particles exhibit morphological changes during an annealing program which can be related to respective phase changes, which have been corroborated by X-ray diffraction and vibrational spectroscopy in former experiments. [1,2] Different techniques of sample preparation have been applied, which range from gas phase deposition, to quenching techniques and oil-matrix isolation of frozen droplets. Beside the assignment of ice and hydrate particles and the evaluation of their impact on the spectroscopic data, we could also identify phase separations into hydrates and ice or impurities. This is an interesting result since it gives an idea of the topology of frozen atmospheric particles, which comprise a mixture of different organic and inorganic substances.[3]
[1] H. Grothe, H. Tizek and I. K. Ortega "Metastable Nitric Acid Hydrates - Possible Constituents of Polar Stratospheric Clouds?" Faraday Discussion 2008, 137, 223-234.
[2] H. Grothe, H. Tizek, D. Waller and D. J. Stokes "The crystallization kinetics and morphology of nitric acid trihydrate" Phys. Chem. Chem. Phys. 2006, 8, 2232-2239.
[3] H. Grothe "Interactive comment on "Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets" by B. J. Murray"; Atmospheric Chemistry and Physics Discussion, 2008, 8, 3992-3995
Microfluidic Step Emulsification: From Fundamental Understanding to the Fabrication of Functional Materials
No full textSavoxepine: striatal dopamine-D2 receptor occupancy in human volunteers measured using positron emission tomography (PET)
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