bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Vanadium on the Continuous Cooling Transformation of 0.7 %C Steel for Railway Wheels
Authors: Fonseca Solange T. , Sinatora Amilton , Ramirez Antonio J. , Minicucci Domingos J. , Afonso Conrado R. , Mei Paulo Roberto
Published: June 2016

To understand the effect of vanadium on the austenite decomposition of a 0.7 %C steel used in railway wheels the Continuous Cooling Transformation (CCT) diagrams were obtained and the microstructures analyzed with optical, SEM, TEM and XRD techniques. Vanadium refined the austenitic grain (12 and 6 μm for 7C and 7V, respectively), what can be explain by the presence of fine (10 nm in diameter) V4C3 precipitates, which restricts the austenitic grain growth. In addition, vanadium, in solid solution, reduced the pearlite interlamelar spacing (0.13 and 0.11 μm for 7C and 7V, respectively) by depressing the initial temperature pearlite formation (644 and 639 °C for 7C and 7V, respectively). He increased the ferrite volume fraction from 1 to 3 % at cooling rate of 1 oC/s, due the fact that vanadium is a ferrite stabilizer. Vanadium addition did not affect the initial temperature for martensite formation, but increased the hardenability with martensite formation at slower cooling rates (10 and 5 oC/s for 7C and 7V, respectively). For higher cooling rates (20 to 100 oC/s), the austenite transformation to martensite at room temperature was incomplete and all steels presented martensite and retained austenite, which volumetric fraction was near the same for both steels varying from 20 to 40 %.
Brazing Vacuum Ceramic Tubes - A Diffusion Profile in the Joint
Authors: Bagnato Osmar Roberto , Francisco R.F. , Gobbi A.L. , Falvo Tatiane , Pimentel P.M.
Published: June 2016

The Sirius Project is an initiative of the Brazilian Synchrotron Light Laboratory - LNLS (CNPEM - MCTI), for the design, construction and operation of a new synchrotron radiation source 3rd generation, with high brightness and energy of the electrons of 3.0 GeV. Among many other components there will be built 80 ceramic cameras embedded in special magnets, whose function is to act to correct the orbit of the electron beam in the storage ring. The ceramic chamber is crucial for this application because this material is transparent to the magnetic field generated in the electro magnet and thus acts directly on the electron beam. The difficulty of these constructive components lies in the fact that, the ceramic components must be attached to metal components will join vacuum chambers that make up the ring, and then must present excellent mechanical and vacuum tight. The process of chemical bonding between the ceramic and metal components is performed by brazing in high vacuum. After brazing, a film is deposited of copper with 7 micrometers thickness. The objective of this paper is to describe the process of film deposition and brazing of copper and the excellent results obtained in the production, mechanical characterization, microstructural and tightness.
Strain Energy Cumulation at Increased Temperatures
Authors: Mrozinski Stanislaw
Published: June 2016

This paper presents results of strain energy ΔWpl cumulation tests on cast steel specimens under constant-amplitude isothermal stress conditions and programed block stress conditions at three different temperatures (20, 400, 600°C). Programed loads (blocks) were composed of five stages of different sequences which included the same strain as during the constant-amplitude isothermal tests. Through the constant-amplitude tests the author demonstrated effect of temperature and the strain level on the fatigue life, strain energy value ΔWpl and accumulated energy ΣΔWpl. While no influence of the load program form on the value of the energy accumulated in the specimen was found.
The Influence of Multiaxial Superimposed Static Mean Stress on High-Cycle Fatigue Life of Cu-ETP Copper
Authors: Pejkowski Lukasz , Skibicki Dariusz , Wirwicki Mateusz
Published: June 2016

High–cycle multiaxial fatigue tests under proportional and non-proportional loading conditions with various combinations of superimposed static mean stresses was carried out on Cu-ETP copper. The results show differences in fatigue life between various ratios of mean stresses. These results are similar to others described in the literature.
Alternative Method for the Determination of a Full S-N Fatigue Profile
Authors: Strzelecki Przemysław , Sempruch Janusz , Tomaszewski Tomasz
Published: June 2016

This paper presents two methods for estimating the S-N fatigue curve. The first is the traditional linear regression and staircase method. The other, alternative, method is based on random fatigue life, fatigue limit and probability. The both methods provide similar results but the latter one requires fewer test samples
Description of Fatigue Characteristics for Welded Joints in FITNET Procedures – Selected Issues
Authors: Szala Grzegorz
Published: June 2016

Discontinuity of geometrical and material properties of welded joints makes it difficult to describe unequivocally the fatigue properties of these joints. The effect of the above mentioned difficulties is that in FITNET procedures, in 1a path of a fatigue module, these properties are described by means of a fatigue diagrams in the form of fatigue curves S-N (Wöhler curves), based on a characteristic parameter - class FAD, and slope factor m = const. FITNET procedures contain a table of elementary nodes (welded joints), which are matched by particular diagrams of appropriate FAD classes.A problem occurs when in a set of elements there is no element with properties similar to the element which is being calculated.
Influence of Metal Foil on Interface Stress State in CFRP Laminate
Authors: Szymczyk Elżbieta , Puchała Krzysztof , Jachimowicz Jerzy , Salacinski Michal
Published: June 2016

Various materials of high specific stiffness and strength are used in aircraft structures, therefore, methods of joining them are continually improved. Adhesive joining is the most popular method used in composite structures, however, mechanical joining is often necessary due to constructional reasons. Stress concentration around the hole (notch) and point load (fastener action) transfer into the structure are the main disadvantages of mechanical joints, especially, in composite structures. The bearing failure is the only global progressive mechanism of mechanically fastened laminates and therefore it is the acceptable one. Different attempts to improve bearing performance of laminates have been considered by many authors. One of the most interesting solutions is bonding the titanium foils (thin inserts) into the composite structure. The aim of the paper is analysis of a metal insert influence on the stress state around the hole. Specimens made of carbon fibre reinforced plastic and locally modified laminate (part of prepreg layer around the hole is replaced with a circular titanium foil) have been taken into account. The specimens were manufactured in a co-curing process using autoclave technology. Nonlinear analyses were carried out with Marc code. In a locally modified laminate, the main mechanism of load transfer is interlaminar shear stress. The area of load transfer is augmented by the area of metal-fibre adhesive joining. A significant part of the applied load is carried by titanium foils, then it is gradually transferred by means of shear stresses due to adhesion between titanium foils and laminate layers. Bearing performance depends on the insert material stiffness and its elasto-plastic behaviour. Bearing stiffness reduction is strongly influenced by parameters of the titanium-laminate adhesive interface.
Numerical Simulation of Void Nucleation in S355 Steel
Authors: Wcislik Wiktor
Published: June 2016

The study presents the numerical simulation of the void nucleation process due to decohesion of the interface between the matrix and inclusion of iron carbide Fe3C, under high stress state triaxiality ratio, which is equal to 1.345. The analysis was conducted for S355J2G3 steel, commonly used in civil engineering structures. Special attention was paid to the determination of the value of void nucleation strain.
Effect of Frictional-Mechanical Treatment of the Low Alloy Steels on Some Exploitation Properties in Sea Water Simulated Solution
Authors: Kocanda Dorota , Jurczak Wojciech , Lunarska Ellina , Swiatek Krzysztof
Published: June 2016

Abstract. Paper presents the results of the studies of the service properties of the 235JR and S355J2 low alloy steels subjected to the surface modification by friction-mechanical treatment, as tested in sea water simulated solution. The resistance of steels used in the marine vessels to the wear, cavitation erosion, general corrosion, corrosion cracking and hydrogen absorption has been examined. To evaluate the effect of the surface treatment, the comparative studies of the service properties of steels before and after treatment have been considered.
Failure of Steel Bridges due to Constraint Induced Fracture
Authors: Kossakowski Paweł Grzegorz
Published: June 2016

This paper discusses issues related to the failure of steel bridge structures attributable to a certain type of fracture called Constraint Induced Fracture (CIF). It focuses on the causes of and factors associated with this phenomenon as it has been responsible for the failure of several bridges in the last dozen years. The strength aspects of the CIF phenomenon are analyzed using the example of the failure of the Hoan Bridge over the Milwaukee River in the US.
Comparison of 15Mo3 Strain Curves Obtained for Strain-Controlled Cyclic Bending and Tension-Compression Tests
Authors: Kulesa Anna , Kurek Andrzej , Łagoda Tadeusz , Achtelik Henryk , Kluger Krzysztof
Published: June 2016

The paper presents a comparison of the fatigue life curves based on test of 15Mo3 steel under cyclic, pendulum bending and tension-compression. These studies were analyzed in terms of a large and small number of cycles where strain amplitude is dependent on the fatigue life. It has been shown that commonly used Manson-Coffin-Basquin model cannot be used for tests under cyclic bending due to the impossibility of separating elastic and plastic strains. For this purpose, some well-known models of Langer and Kandil and one new model of authors, where strain amplitude is dependent on the number of cycles, were proposed. Comparing the results of bending with tension-compression it was shown that for smaller strain amplitudes the fatigue life for both test methods were similar, for higher strain amplitudes fatigue life for bending tests was greater than for tension-compression.
Morphological Diversity of Complex Thalloid Liverwort Genera of Sri Lanka
Authors: Ruklani N. C. S , Rubasinghe S. C. K , Long D. G
Published: June 2016

As part of a study initiated to trace the evolutionary relationships and biogeographic affinities of Sri Lankan complex thalloid liverworts, we here present the morphological diversity of Sri Lankan complex thalloid liverworts. This serves as the first detailed taxonomic study of the group in Sri Lanka.  Specimens were collected from different geographical regions covering almost all topographic and climatic zones of the country. This study revealed 9 genera of complex thalloid liverworts in Sri Lanka. Based on our collections and identifications we prepared a generic key to Sri Lankan complex thalloid liverworts. Taxonomic descriptions were prepared for all identified genera
Morphological and genetic polymorphism in two North American reindeer lichens: Cladonia arbuscula and C. rangiferina
Authors: Athukorala Sarangi N. P. , Doering Jennifer , Piercey-Normore Michele D.
Published: June 2016

Cladonia arbuscula and C. rangiferina are two reindeer lichen species, which are widely distributed in northern climates and have not been shown to be monophyletic, suggesting incomplete lineage sorting and speciation. The wide species distribution may suggest strong adaptive potential and an outcrossing reproductive life style, which might explain the lack of monophyly and success of these two species. The current study examined the genetic diversity of mycobiont ascospore colonies within and between apothecia of two species, C. rangiferina and C. arbuscula s. l. using Randomly Amplified Polymorphic DNA (RAPD)-PCR, estimates of gene flow, morphology, and colony growth rates. Cladonia rangiferina showed higher rates of growth than C. arbuscula but more variability in growth between apothecia was observed in C. arbuscula than C. rangiferina. Both species showed levels of genetic variation within and among apothecia that was consistent with heterothallism and recombination. AMOVA analyses provided evidence for gene flow among apothecia in both species. It is hypothesized that higher genetic variation in C. arbuscula than in C. rangiferina may give C. arbuscula an adaptive advantage over C. rangiferina.
Effect of 1-methylcyclopropene (1-mcp) treatment on postharvest quality and antifungal activity of avocado cv. ‘pollock’ under tropical storage conditions
Authors: Daulagala C. H. , Daundasekera W. A. M.
Published: June 2016

1-MCP is a competitive, gaseous ethylene inhibitor, which binds irreversibly to ethylene receptors and thereby blocks effects of ethylene in plants. The potential for 1-MCP to delay ripening in avocado cv. ‘Pollock’ fruit was examined under tropical ambient storage conditions. Fruits harvested at commercial maturity were exposed to 300 nll-1 1-MCP gas for 20 h under 27± 2 ˚C and then stored under ambient conditions (27± 2 ˚C and relative humidity 65 ± 2%). Fruits were assessed daily for fresh weight, firmness, skin colour, fungal rot development and glossiness. The antifungal activity in diethylether extracts of fruit peel was assessed through thin layer chromatography (TLC) coupled with Cladosporium bioassay. Exposure to 1-MCP extended the shelf life up to 9 days of fruit by 2.2 fold as compared to the shelf life of 4 days of the controls. Stem end rot caused by Botryodiplodia theobromae was found to be the shelf-life determining factor of the fruits. 1-MCP treatment resulted in a significant (p< 0.05) delay in change in peel colour, softening and glossiness of fruit as compared to the controls. Bioassays using Cladosporium fungus revealed the presence of antifungal activity at Rf0.75 in both 1-MCP treated and control fruits. 1-MCP treatment was effective in delaying the decline of antifungal activity in fruit apparently along with the delay of other ripening-related changes and minimizing losses encountered during storage under warmer ambient conditions.
Phenetic analysis and phytochemical screening of medicinally important Albizia spp. in Sri Lanka
Authors: Jayasiri A. P. A , Senanayake S. P. , Paranagama P. , Amarasinghe A. P. G.
Published: June 2016

Albizia Durazz. is a genus of 150 species in the tropics and subtropics of the world and belongs to the sub family Mimosaceae in the Family Fabaceae. Of the six species recorded in Sri Lanka, A. lebbeck is used as a shady tree while A. odoratissima is grown mainly for their timber value, However, A. odoratissima and A. lebbeck are found to be used in ayurvedic medicine however, the medicinal properties of these species are not fully understood. A questionnaire survey was carried out using a hundred sample population to identify their medicinal usage. Floral and vegetative characters of the above two Albizia spp. were observed and phenetic relationships were identified. Air dried stem barks of A. odoratissima and A. lebbeck were subjected to sequential solvent extraction using hexane, chloroform, methanol and water, and the crude weight of the yield were obtained. The results revealed that ayurvedic physicians and traditional ayurvedic medical practitioners use A. odoratissima in medicinal preparations whereas the medicinal use of A. lebbeck is not reported. Further, it was revealed that Samanea saman and Adenanthera pavonina are commonly used as substitutes for A. lebbeck. Knowledge of phenetic variation of the two Albizia spp. can be used for accurate identification which prevents adulteration. Highest yield was obtained from the methanolic extracts. These extracts were subjected to preliminary phytochemical screening to assess the occurrence of different phytochemicals. Results have shown the presence of glylcosides, tannins, phenolics, phytosteroids and flavonoids in methanolic extracts A. odoratissima, and A. lebbeck.  The present study suggests that further studies should be conducted on the identification of active compounds in these two plant species for their pharmacognostic properties in order to understand their mode of remedial action for ailments.
The Lung Microbiome, Immunity, and the Pathogenesis of Chronic Lung Disease
Authors: O’Dwyer David N. , Dickson Robert P. , Moore Bethany B.
Published: June 2016

The development of culture-independent techniques for microbiological analysis has uncovered the previously unappreciated complexity of the bacterial microbiome at various anatomic sites. The microbiome of the lung has relatively less bacterial biomass when compared with the lower gastrointestinal tract yet displays considerable diversity. The composition of the lung microbiome is determined by elimination, immigration, and relative growth within its communities. Chronic lung disease alters these factors. Many forms of chronic lung disease demonstrate exacerbations that drive disease progression and are poorly understood. Mounting evidence supports ways in which microbiota dysbiosis can influence host defense and immunity, and in turn may contribute to disease exacerbations. Thus, the key to understanding the pathogenesis of chronic lung disease may reside in deciphering the complex interactions between the host, pathogen, and resident microbiota during stable disease and exacerbations. In this brief review we discuss new insights into these labyrinthine relationships.
Jeremiah 23:23–24 as polemic against prophets’ views on Yahweh’s presence
Authors: Wessels Wilhelm
Published: June 2016

Jeremiah 23:23–24 is a short passage in the cycle of oracles in which the prophet Jeremiah is supposedly in conflict with other prophets in his society. It is possible that this short passage first had an independent existence before it became part of the collection of oracles in 23:9-40 This article argues that as an independent oracle the passage claims that Yahweh is not just a localised god, but an omnipresent God from whom no person can hide. When read as part of the mentioned cycle, it should be regarded as a polemic against a view held by some prophets that Yahweh’s nearness guarantees peace and security. Their domesticated view leads to complacency and disregard. It is argued that Jeremiah opposes their view by stating that Yahweh is also a distant God who is aware of their false and deceitful attempts to provide revelatory knowledge to the people. In this regard chapter 23:23–24 serves as a polemic against so-called false prophets and implies a threat of judgement.Keywords: False prophets, temple, Yahweh's presence, polemic
Peano on definition of surface area
Authors: Greco Gabriele H. , Mazzucchi Sonia , Pagani Enrico M.
Published: June 2016

In this paper we investigate the evolution of the concept of surface area in Peano’s mathematical research, taking into account the main role played by Grassmann’s geometric-vector calculus and Peano’s theory on derivative of measures. Geometric (in
Applicazioni geometriche
, 1887) and bi-vector (in
Calcolo geometrico
, 1888) Peano’s approaches to surface area, culminating into the celebrated Peano’s paper
Sulla definizione dell’area d’una superficie
, presented by Casorati for publication on
Rendiconti dell’Accademia dei Lincei
in 1890 and re-proposed in Peano’s textbook
Lezioni di analisi infinitesimale
(1893), mark the development of this topic during the first half of the last century. Moreover we will present some remarkable contributions on surface area that are inspired and/or closely related to Peano’s definition.
Duality for $A_\infty$ weights on the real line
Authors: D'Onofrio Luigi , Popoli Arturo , Schiattarella Roberta
Published: June 2016

Under the same bounds on

G_q

-constants and

A_p

-constants, the optimal exponents for sharp inclusions between Gehring

G_q

-class of weights and Muckenhoupt

A_p

-class (

1 < p, q < \infty

) are Hölder conjugate, if

p

and

q

are conjugate. This is a consequence of a representation theorem of

A_\infty

weights in terms of

W^{1,r}

-biSobolev maps and a duality result between

G_q

and

A_p

classes in dimension one. We prove also that sharp a priori bounds on constants correspond under the Hölder conjugate mapping

\phi(t)= \frac{t}{t-1}

.
On maximal and potential operators with rough kernels in variable exponent spaces
Authors: Rafeiro Humberto , Samko Stefan
Published: June 2016

In the framework of variable exponent Lebesgue and Morrey spaces we prove some boundedness results for operators with rough kernels, such as the maximal operator, fractional maximal operator, sharp maximal operators and fractional operators. The approach is based on some pointwise estimates.
Continuity estimates for $p$-Laplace type operators in Orlicz–Zygmund spaces
Authors: Farroni Fernando
Published: June 2016

We study the Dirichlet problem

\mathrm {div} \: \mathcal A (x, \nabla u) = \mathrm {div} \: f \;\; \mathrm {in} \; \Omega,

u = 0 \;\; \mathrm {on}\; \partial \Omega,

in a bounded Lipschitz domain

\Omega\subset \mathbb R^N

, with

N \ geq 2

. The vector field

\mathcal A \colon \Omega \times \mathbb R^N \rightarrow \mathbb R^N

satisfies the typical growth and coercivity conditions of the

p

-Laplacian type operator with

p>1

. We prove existence and uniqueness results in the case the vector field

f

belongs to the Orlicz–Zygmund space

\mathcal L^q \: \mathrm {log}^{–\alpha} \mathcal L (\mathrm {log} \: \mathrm {log} \: \mathcal L)^{– \beta} (\Omega, \mathbb R^N), q = \frac {p} {p-1}, \alpha > 0

and

\beta \in \mathbb R

or

\alpha = 0

and

\beta > 0

. In particular, the gradient of the solution belongs to

\mathcal L^q \: \mathrm {log}^{–\alpha} \: \mathcal L (\mathrm {log} \: \mathrm {log} \: \mathcal L)^{– \beta} (\Omega, \mathbb R^N)

. Further, we provide estimates implying the continuity of the operator which carries any given

f

into the gradient field

\nabla u

of the solution.
Measurements of global distributions of polar mesospheric clouds during 2005–2012 by MIPAS/Envisat
Authors: García-Comas Maya , López-Puertas Manuel , Funke Bernd , Jurado-Navarro Á. Aythami , Gardini Angela , Stiller Gabriele P. , von Clarmann Thomas , Höpfner Michael
Published: June 2016

Abstract. We have analysed MIPAS (Michelson Interferometer for Passive Atmopheric Sounding) infrared measurements of PMCs for the summer seasons in the Northern (NH) and Southern (SH) hemispheres from 2005 to 2012. Measurements of PMCs using this technique are very useful because they are sensitive to the total ice volume and independent of particle size. For the first time, MIPAS has provided coverage of the PMC total ice volume from midlatitudes to the poles. MIPAS measurements indicate the existence of a continuous layer of mesospheric ice, extending from about  ∼ 81 km up to about 88–89 km on average and from the poles to about 50–60° in each hemisphere, increasing in concentration with proximity to the poles. We have found that the ice concentration is larger in the Northern Hemisphere than in the Southern Hemisphere. The ratio between the ice water content (IWC) in both hemispheres is also latitude-dependent, varying from a NH ∕ SH ratio of 1.4 close to the poles to a factor of 2.1 around 60°. This also implies that PMCs extend to lower latitudes in the NH. A very clear feature of the MIPAS observations is that PMCs tend to be at higher altitudes with increasing distance from the polar region (in both hemispheres), particularly equatorwards of 70°, and that they are about 1 km higher in the SH than in the NH. The difference between the mean altitude of the PMC layer and the mesopause altitude increases towards the poles and is larger in the NH than in the SH. The PMC layers are denser and wider when the frost-point temperature occurs at lower altitudes. The layered water vapour structure caused by sequestration and sublimation of PMCs is present at latitudes northwards of 70° N and more pronounced towards the pole. Finally, MIPAS observations have also shown a clear impact of the migrating diurnal tide on the diurnal variation of the PMC volume ice density.
Substantial secondary organic aerosol formation in a coniferous forest: observations of both day- and nighttime chemistry
Authors: Lee Alex K. Y. , Abbatt Jonathan P. D. , Leaitch W. Richard , Li Shao-Meng , Sjostedt Steve J. , Wentzell Jeremy J. B. , Liggio John , Macdonald Anne Marie
Published: June 2016

Abstract. Substantial biogenic secondary organic aerosol (BSOA) formation was investigated in a coniferous forest mountain region in Whistler, British Columbia. A largely biogenic aerosol growth episode was observed, providing a unique opportunity to investigate BSOA formation chemistry in a forested environment with limited influence from anthropogenic emissions. Positive matrix factorization of aerosol mass spectrometry (AMS) measurement identified two types of BSOA (BSOA-1 and BSOA-2), which were primarily generated by gas-phase oxidation of monoterpenes and perhaps sesquiterpenes. The temporal variations of BSOA-1 and BSOA-2 can be explained by gas–particle partitioning in response to ambient temperature and the relative importance of different oxidation mechanisms between day and night. While BSOA-1 arises from gas-phase ozonolysis and nitrate radical chemistry at night, BSOA-2 is likely less volatile than BSOA-1 and consists of products formed via gas-phase oxidation by OH radical and ozone during the day. Organic nitrates produced through nitrate radical chemistry can account for 22–33 % of BSOA-1 mass at night. The mass spectra of BSOA-1 and BSOA-2 have higher values of the mass fraction of m/z 91 (f91) compared to the background organic aerosol. Using f91 to evaluate BSOA formation pathways in this unpolluted, forested region, heterogeneous oxidation of BSOA-1 is a minor production pathway of BSOA-2.
The aerosol radiative effects of uncontrolled combustion of domestic waste
Authors: Kodros John K. , Cucinotta Rachel , Ridley David A. , Wiedinmyer Christine , Pierce Jeffrey R.
Published: June 2016

Abstract. Open, uncontrolled combustion of domestic waste is a potentially significant source of aerosol; however, this aerosol source is not generally included in many global emissions inventories. To provide a first estimate of the aerosol radiative impacts from domestic-waste combustion, we incorporate the Wiedinmyer et al. (2014) emissions inventory into GEOS-Chem-TOMAS, a global chemical-transport model with online aerosol microphysics. We find domestic-waste combustion increases global-mean black carbon and organic aerosol concentrations by 8 and 6 %, respectively, and by greater than 40 % in some regions. Due to uncertainties regarding aerosol optical properties, we estimate the globally averaged aerosol direct radiative effect to range from −5 to −20 mW m−2; however, this range increases from −40 to +4 mW m−2 when we consider uncertainties in emission mass and size distribution. In some regions with significant waste combustion, such as India and China, the aerosol direct radiative effect may exceed −0.4 W m−2. Similarly, we estimate a cloud-albedo aerosol indirect effect of −13 mW m−2, with a range of −4 to −49 mW m−2 due to emission uncertainties. In the regions with significant waste combustion, the cloud-albedo aerosol indirect effect may exceed −0.4 W m−2.
Effect of volcanic aerosol on stratospheric NO2 and N2O5 from 2002–2014 as measured by Odin-OSIRIS and Envisat-MIPAS
Authors: Adams Cristen , Bourassa Adam E. , McLinden Chris A. , Sioris Chris E. , von Clarmann Thomas , Funke Bernd , Rieger Landon A. , Degenstein Douglas A.
Published: June 2016

Abstract. Following the large volcanic eruptions of Pinatubo in 1991 and El Chichón in 1982, decreases in stratospheric NO2 associated with enhanced aerosol were observed. The Optical Spectrograph and InfraRed Imaging Spectrometer (OSIRIS) likewise measured widespread enhancements of stratospheric aerosol following seven volcanic eruptions between 2002 and 2014, although the magnitudes of these eruptions were all much smaller than the Pinatubo and El Chichón eruptions. In order to isolate and quantify the relationship between volcanic aerosol and NO2, NO2 anomalies were calculated using measurements from OSIRIS and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). In the tropics, variability due to the quasi-biennial oscillation was subtracted from the timeseries. OSIRIS profile measurements indicate that the strongest relationships between NO2 and volcanic aerosol extinction were for the layer ~ 3–7 km above the tropopause, where OSIRIS stratospheric NO2 partial columns for ~ 3–7 km above the tropopause were found to be smaller than baseline levels during these aerosol enhancements by up to ~ 60 % with typical Pearson correlation coefficients of R ~ −0.7. MIPAS also observed decreases in NO2 partial columns during periods of affected by volcanic aerosol, with percent differences of up to ~ 25 %. An even stronger relationship was observed between OSIRIS aerosol optical depth and MIPAS N2O5 partial columns, with R ~ −0.9, although no link with MIPAS HNO3 was observed. The variation of OSIRIS NO2 with increasing aerosol was found to be quantitatively consistent with simulations from a photochemical box model in terms of both magnitude and degree of non-linearity.
First detection of ammonia (NH3) in the Asian monsoon upper troposphere
Authors: Höpfner Michael , Volkamer Rainer , Grabowski Udo , Grutter Michel , Orphal Johannes , Stiller Gabriele , von Clarmann Thomas , Wetzel Gerald
Published: June 2016

Abstract. Ammonia (NH3) has been detected in the upper troposphere by analysis of averaged MIPAS (Michelson Interferomter for Passive Atmospheric Sounding) infrared limb-emission spectra. We have found enhanced amounts of NH3 within the region of the Asian monsoon at 12–15 km altitude. Three-monthly, 10° longitude x 10° latitude average profiles reaching maximum mixing ratios of around 30 pptv in this altitude range have been retrieved with a vertical resolution of 3–8 km and estimated errors of about 5 pptv. These observations show that loss processes during transport from the boundary layer to the upper troposphere within the Asian monsoon do not deplete the air entirely of NH3. Thus, ammonia might contribute to the so-called Asian tropopause aersol layer by formation of ammonium aerosol particles. On a global scale, outside the monsoon area and during different seasons, we could not detect enhanced values of NH3 above the actual detection limit of about 3–5 pptv. This upper bound helps to constrain global model simulations.
Trends of tropical tropospheric ozone from twenty years of European satellite measurements and perspectives for Sentinel-5 Precursor
Authors: Heue Klaus-Peter , Coldewey-Egbers Melanie , Delcloo Andy , Lerot Christophe , Loyola Diego , Valks Pieter , van Roozendael Michel
Published: June 2016

Abstract. In preparation of the TROPOMI/S5P launch in autumn 2016 a tropospheric ozone retrieval based on the convective cloud differential method was developed. For intensive tests we applied the algorithm to the total ozone columns and cloud data of the satellites GOME, SCIAMACHY, OMI, GOME-2A and GOME-2B. Thereby a time series of 20 years (1995–2015) of tropospheric ozone columns was retrieved. To have a consistent total ozone data set for all sensors one common retrieval algorithm, namely GODFITv3, has been applied to all sensors and the L1 reflectances have also been soft calibrated. These data were input into the tropospheric ozone retrieval. However, the Tropical Tropospheric Ozone Columns (TTOC) for the individual instruments still showed small differences and therefore we harmonised the data set. For this purpose a multi-variant function was fitted to the averaged difference between SCIAMACHY's TTOC and those from the other sensors. The original TTOC was corrected by the fitted offset. GOME-2B data were corrected relative to the harmonised data from OMI and GOME-2A. The harmonisation leads to a better agreement between the different instruments. Also a direct comparison of the TTOCs in the overlapping periods proves that GOME-2A agrees much better with SCIAMACHY after the harmonisation. The improvements for OMI were small. The GOME and SCIAMACHY data overlap for one year for the complete tropics, this turned out to be insufficient to extrapolate back until 1995. Based on the harmonised observations, we created a merged data product, containing the TTOC from July 1995 to Dec. 2015. A first application of this 20 years record is a trend analysis. The global tropical trend is 0.75 ± 0.12 DU decade−1. Regionally the trends reaches up to 1.8 DU decade−1 like on the African Atlantic coast, over the Western Pacific the tropospheric ozone declined over the last 20 years with up to 0.8 DU decade−1. The tropical tropospheric data record will be extended in the future with the TROPOMI/S5P data, where the TTOC is part of the operational products.
Reconstructions of biomass burning from sediment-charcoal records to improve data–model comparisons
Authors: Marlon Jennifer R. , Kelly Ryan , Daniau Anne-Laure , Vannière Boris , Power Mitchell J. , Bartlein Patrick , Higuera Philip , Blarquez Olivier , Brewer Simon , Brücher Tim , Feurdean Angelica , Romera Graciela Gil , Iglesias Virginia , Maezumi S. Yoshi , Magi Brian , Courtney Mustaphi Colin J. , Zhihai Tonishtan
Published: June 2016

Abstract. The location, timing, spatial extent, and frequency of wildfires are changing rapidly in many parts of the world, producing substantial impacts on ecosystems, people, and potentially climate. Paleofire records based on charcoal accumulation in sediments enable modern changes in biomass burning to be considered in their long-term context. Paleofire records also provide insights into the causes and impacts of past wildfires and emissions when analyzed in conjunction with other paleoenvironmental data and with fire models. Here we present new 1000-year and 22 000-year trends and gridded biomass burning reconstructions based on the Global Charcoal Database version 3 (GCDv3), which includes 736 charcoal records (57 more than in version 2). The new gridded reconstructions reveal the spatial patterns underlying the temporal trends in the data, allowing insights into likely controls on biomass burning at regional to global scales. In the most recent few decades, biomass burning has sharply increased in both hemispheres but especially in the north, where charcoal fluxes are now higher than at any other time during the past 22 000 years. We also discuss methodological issues relevant to data–model comparisons and identify areas for future research. Spatially gridded versions of the global data set from GCDv3 are provided to facilitate comparison with and validation of global fire simulations.
Carbon uptake and water use in woodlands and forests in southern Australia during an extreme heat wave event in the ‘Angry Summer’ of 2012/2013
Authors: van Gorsel Eva , Wolf Sebastian , Isaac Peter , Cleverly James , Haverd Vanessa , Ewenz Cäcilia , Arndt Stefan , Beringer Jason , Resco de Dios Víctor , Evans Bradley J. , Griebel Anne , Hutley Lindsay B. , Keenan Trevor , Kljun Natascha , Macfarlane Craig , Meyer Wayne S. , McHugh Ian , Pendall Elise , Prober Suzanne , Silberstein Richard
Published: June 2016

Abstract. As a result of climate change warmer temperatures are projected through the 21st century and are already increasing above modelled predictions. Apart from increases in the mean, warm/hot temperature extremes are expected to become more prevalent in the future, along with an increase in the frequency of droughts. It is crucial to better understand the response of terrestrial ecosystems to such temperature extremes for predicting land-surface feedbacks in a changing climate. During the 2012/2013 summer, Australia experienced a record-breaking heat wave with an exceptional spatial extent that lasted for several weeks. We synthesized eddy-covariance measurements from seven woodland and forest sites across climate zones in southern Australia, which we combined with model simulations from the CABLE land surface model to investigate the effect of this summer heat wave on the carbon and water exchange of terrestrial ecosystems. We found that the water-limited woodlands and the energy-limited forest ecosystem responded differently to the heat wave. During the most intense part of the heat wave, the woodlands experienced decreased latent heat flux, an increased Bowen ratio and a reduced carbon uptake while the forest ecosystem had increased latent heat flux, reduced Bowen ratio and increased carbon uptake. Ecosystem respiration was increased at all sites resulting in reduced net ecosystem productivity in the woodlands and constant net ecosystem productivity in the forest. Importantly all ecosystems remained carbon sinks during the event. Precipitation after the most intense first part of the heat wave and slightly cooler temperatures led to a decrease of the Bowen ratio and hence increased evaporative cooling. Carbon uptake in the woodlands also recovered quickly but respiration remained high. While woodlands and forest proved relatively resistant to this short-term heat extreme these carbon sinks may not sustainable in a future with an increased number, intensity and duration of heat waves.
Stable carbon isotopes of dissolved inorganic carbon for a zonal transect across the subpolar North Atlantic Ocean in summer 2014
Authors: Humphreys Matthew P. , Greatrix Florence M. , Tynan Eithne , Achterberg Eric P. , Griffiths Alex M. , Fry Claudia H. , Garley Rebecca , McDonald Alison , Boyce Adrian J.
Published: June 2016

Abstract. The stable carbon isotope composition of dissolved inorganic carbon (δ13CDIC) in seawater was measured in samples collected during June–July 2014 in the subpolar North Atlantic. Sample collection was carried out on the RRS James Clark Ross cruise JR302, part of the “Radiatively Active Gases from the North Atlantic Region and Climate Change” (RAGNARoCC) research programme. The observed δ13CDIC values for cruise JR302 fall in a range from −0.07 to +1.95 ‰, relative to the Vienna Pee Dee Belemnite standard. From duplicate samples collected during the cruise, the 1σ precision for the 341 results is 0.08 ‰, which is similar to our previous work and other studies of this kind. We also performed a cross-over analysis using nearby historical δ13CDIC data, which indicated that there were no significant systematic offsets between our measurements and previously published results. We also included seawater reference material (RM) produced by A. G. Dickson (Scripps Institution of Oceanography, USA) in every batch of analysis, enabling us to improve upon the calibration and quality-control procedures from a previous study. The δ13CDIC is consistent within each RM batch, although its value is not certified. We report δ13CDIC values of 1.15 ± 0.03 ‰ and 1.27 ± 0.05 ‰ for batches 141 and 144 respectively. Our JR302 δ13CDIC data can be used – along with measurements of other biogeochemical variables – to constrain the processes that control DIC in the interior ocean, in particular the oceanic uptake of anthropogenic carbon dioxide and the biological carbon pump. Our δ13CDIC results are available from the British Oceanographic Data Centre – doi:10.5285/22235f1a-b7f3-687f-e053-6c86abc0c8a6.
Glaciation's topographic control on Holocene erosion at the eastern edge of the Alps
Authors: Dixon Jean L. , von Blanckenburg Friedhelm , Stüwe Kurt , Cristl Marcus
Published: June 2016

Abstract. What is the influence of glacial processes in driving erosion and uplift across the European Alps? It has largely been argued that repeated erosion through glaciation sustains isostatic uplift and topography in a decaying orogen. But, some insist that the Alps are an orogen still actively uplifting (e.g., Hergarten et al., 2010). We add insight to this debate by isolating the role of post-glacial topographic forcing on erosion rates. To do this, we quantify the topographic signature of past glaciation on millennial scale erosion rates in previously glaciated and unglaciated catchments at the easternmost edge of the Austrian Alps. Newly measured catchment-wide erosion rates, determined from cosmogenic 10Be in river-borne quartz, correlate with basin relief and mean slope. GIS-derived slope-elevation and slope-area distributions across catchments provide clear topographic indicators of the degree of glacial preconditioning, which further correlates with erosion rates. Erosion rates in the eastern-most, non-glaciated basins range from 40 to 150 mm/ky and likely reflect underlying tectonic forcings in this region, which have previously been attributed to recent (post 5 Ma) uplift (Legrain et al., 2015). By contrast, erosion rates in previously glaciated catchments range from 170 to 240 mm/ky and reflect the erosional response to local topographic preconditioning by repeated glaciations. Together, these data suggest that Holocene erosion across the Eastern Alps is strongly shaped by the local topography relict from previous glaciations. Broader, landscape-wide forcings, such as the widely debated deep mantle-driven or isostatically-driven uplift, result in lesser controls on both topography and erosion rates in this region. Comparing our data to previously published erosion rates across the Alps, we show that post-glacial erosion rates vary across more than two orders of magnitude with poor topographic indicators of controls. This high variation in post-glacial erosion may reflect combined effects of direct tectonic and modern climatic forcings, but is strongly overprinted by past glacial climate and its topographic legacy.
A new subgrid-scale representation of hydrometeor fields using a multivariate PDF
Authors: Griffin Brian M. , Larson Vincent E.
Published: June 2016

Abstract. The subgrid-scale representation of hydrometeor fields is important for calculating microphysical process rates. In order to represent subgrid-scale variability, the Cloud Layers Unified By Binormals (CLUBB) parameterization uses a multivariate probability density function (PDF). In addition to vertical velocity, temperature, and moisture fields, the PDF includes hydrometeor fields. Previously, hydrometeor fields were assumed to follow a multivariate single lognormal distribution. Now, in order to better represent the distribution of hydrometeors, two new multivariate PDFs are formulated and introduced.The new PDFs represent hydrometeors using either a delta-lognormal or a delta-double-lognormal shape. The two new PDF distributions, plus the previous single lognormal shape, are compared to histograms of data taken from large-eddy simulations (LESs) of a precipitating cumulus case, a drizzling stratocumulus case, and a deep convective case. Finally, the warm microphysical process rates produced by the different hydrometeor PDFs are compared to the same process rates produced by the LES.
Sharing water and benefits in transboundary river basins
Authors: Arjoon Diane , Tilmant Amaury , Herrmann Markus
Published: June 2016

Abstract. The equitable sharing of benefits in transboundary river basins is necessary to solve disputes among riparian countries and to reach a consensus on basin-wide development and management activities. Benefit-sharing arrangements must be collaboratively developed to be perceived not only as efficient, but also as equitable in order to be considered acceptable to all riparian countries. The current literature mainly describes what is meant by the term benefit sharing in the context of transboundary river basins and discusses this from a conceptual point of view, but falls short of providing practical, institutional arrangements that ensure maximum economic welfare as well as collaboratively developed methods for encouraging the equitable sharing of benefits. In this study, we define an institutional arrangement that distributes welfare in a river basin by maximizing the economic benefits of water use and then sharing these benefits in an equitable manner using a method developed through stakeholder involvement. We describe a methodology in which (i) a hydrological model is used to allocate scarce water resources, in an economically efficient manner, to water users in a transboundary basin, (ii) water users are obliged to pay for water, and (iii) the total of these water charges is equitably redistributed as monetary compensation to users in an amount determined through the application of a sharing method developed by stakeholder input, thus based on a stakeholder vision of fairness, using an axiomatic approach. With the proposed benefit-sharing mechanism, the efficiency–equity trade-off still exists, but the extent of the imbalance is reduced because benefits are maximized and redistributed according to a key that has been collectively agreed upon by the participants. The whole system is overseen by a river basin authority. The methodology is applied to the Eastern Nile River basin as a case study. The described technique not only ensures economic efficiency, but may also lead to more equitable solutions in the sharing of benefits in transboundary river basins because the definition of the sharing rule is not in question, as would be the case if existing methods, such as game theory, were applied, with their inherent definitions of fairness.
MLPNP – A REAL-TIME MAXIMUM LIKELIHOOD SOLUTION TO THE PERSPECTIVE-N-POINT PROBLEM
Authors: Urban S. , Leitloff J. , Hinz S.
Published: June 2016

Abstract. In this paper, a statistically optimal solution to the Perspective-n-Point (PnP) problem is presented. Many solutions to the PnP problem are geometrically optimal, but do not consider the uncertainties of the observations. In addition, it would be desirable to have an internal estimation of the accuracy of the estimated rotation and translation parameters of the camera pose. Thus, we propose a novel maximum likelihood solution to the PnP problem, that incorporates image observation uncertainties and remains real-time capable at the same time. Further, the presented method is general, as is works with 3D direction vectors instead of 2D image points and is thus able to cope with arbitrary central camera models. This is achieved by projecting (and thus reducing) the covariance matrices of the observations to the corresponding vector tangent space.
DETECTING AND ANALYZING CORROSION SPOTS ON THE HULL OF LARGE MARINE VESSELS USING COLORED 3D LIDAR POINT CLOUDS
Authors: Aijazi A. K. , Malaterre L. , Tazir M. L. , Trassoudaine L. , Checchin P.
Published: June 2016

Abstract. This work presents a new method that automatically detects and analyzes surface defects such as corrosion spots of different shapes and sizes, on large ship hulls. In the proposed method several scans from different positions and viewing angles around the ship are registered together to form a complete 3D point cloud. The R, G, B values associated with each scan, obtained with the help of an integrated camera are converted into HSV space to separate out the illumination invariant color component from the intensity. Using this color component, different surface defects such as corrosion spots of different shapes and sizes are automatically detected, within a selected zone, using two different methods depending upon the level of corrosion/defects. The first method relies on a histogram based distribution whereas the second on adaptive thresholds. The detected corrosion spots are then analyzed and quantified to help better plan and estimate the cost of repair and maintenance. Results are evaluated on real data using different standard evaluation metrics to demonstrate the efficacy as well as the technical strength of the proposed method.