bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Material/Geometry of the Section Most Adequate for a Static Loaded Beam Subjected to a Combination of Bending and Torsion
Authors: Silva Hugo Miguel , de Meireles José Filipe Bizarro
Published: November 2012

The acceleration of industrial machines mobile parts has been increasing over the last few years, due to the need of higher production in a short period of time. The machines were dimensioned for a lower value of acceleration, which means there is not enough rigidity for the correct operation at much higher accelerations. Nowadays, the accelerations can be near 12 times the acceleration of gravity. There is the need of improving rigidity to make possible the correct machine operation without undesired vibrations that can ultimately lead to failure. The main applications of this work are plotters and laser cutting machines. To improve rigidity, one must improve the relevant material properties, and the relevant geometric variables of the model.[1] A novel Finite Element Model Updating methodology is presented in this paper. The considered models were : a ribbed plate and a tubular beam. The models were built by means of the Finite Element Method (FEM), and MATLAB was used to control the optimization process, using a programming code. Both material properties and geometric parameters were optimized. The main aim of the materials modeling is to know how the value of the objective function changes with the value of the material properties. Materials selection was performed, using material selection charts, to select the best material for the application. The value of these properties was not in the catalogue, and the properties used to perform the material selection were related to a material sub-class, Eg. Steel. The final material selection determined the best specific material for the application, and that material was mechanically tested. The mechanical tests performed were: Tensile Test and Extensometry Test, to obtain the relevant material properties, mainly Young Modulus, Poisson Coefficient and Yield Stress. The deflection of the optimized models reduced strongly in comparison to the initial models.
Feasibility of the Extended Finite Element Method for the Simulation of Composite Bonded Joints
Authors: Campilho Raul D.S.G. , Pinto Arnaldo M.G. , Banea Mariana D. , Chaves Filipe J.P. , da Silva Lucas F.M.
Published: November 2012

Adhesive-bonding for the unions in multi-component structures is gaining momentum over welding, riveting and fastening. It is vital for the design of bonded structures the availability of accurate damage models, to minimize design costs and time to market. Cohesive Zone Models (CZM’s) have been used for fracture prediction in structures. The eXtended Finite Element Method (XFEM) is a recent improvement of the Finite Element Method (FEM) that relies on traction-separation laws similar to those of CZM’s but it allows the growth of discontinuities within bulk solids along an arbitrary path, by enriching degrees of freedom. This work proposes and validates a damage law to model crack propagation in a thin layer of a structural epoxy adhesive using the XFEM. The fracture toughness in pure mode I (GIc) and tensile cohesive strength (sn0) were defined by Double-Cantilever Beam (DCB) and bulk tensile tests, respectively, which permitted to build the damage law. The XFEM simulations of the DCB tests accurately matched the experimental load-displacement (P-d) curves, which validated the analysis procedure.
Estimating the Age of Lime Mortars by Luminescence to Measure Pollution Rates
Authors: Sanjurjo-Sánchez Jorge , Alves Carlos , Lobarinhas D.
Published: November 2012

Lime mortars can suffer alterations when subjected to gaseous pollutants. Particulate air pollutants can also be deposited and incorporated to the mortar surfaces. Thus, they can be used as pollution tracers allowing us to measure deposition rates of pollutants to compare pollution loads. To calculate deposition rates the absolute age of the studied mortars must be known. Luminescence dating allows estimating the age of lime mortars but involves some partially unsolved problems. Luminescence yields the age of an object from the ratio between paleodose or cumulative radiation dose in the minerals of that object and the annual dose rate of ionizing radiation. The development of optically stimulated luminescence (OSL) in the last years and the application of statistical tools have resulted in the first dating of lime mortars. In this work mortars from old buildings and have been collected from two urban sites (A Coruña, Spain, and Braga, Portugal) to estimate their ages by luminescence. Thus, the mortars could be used as passive samplers to calculate deposition rates and relate these to different pollution loads. Results show partial successful estimates and some related problems in younger mortars are discussed.
Quality Improvement of Recycled Aggregates from a Construction and Demolition Waste Recycling Pilot Plant
Authors: Algarvio D. , Lima Maria Margarida Rolim Augusto , Cunha M.L.
Published: November 2012

The construction and demolition wastes (C&DW) frequently are abandoned in private properties, roads, and landfills or collected by non-licensed companies. In Portugal they are few recycling plants operating with this residue, and this work makes the bridge between the mechanical recycling process developed on semi-industrial scale, and the recycling products characterization process developed on laboratorial scale. The main goal of the present work is the quality improvement of the recycled aggregates produced by a construction and demolition waste recycling pilot plant with 50 ton/h located in Montemor-o-Novo. Process operations are the hammer mill comminution, magnetic separation and sieving (bar sieves: 0-4mm, 4-8mm and 8-12mm; and square sieves: 12-22mm, 22-31mm and above 31mm). In order to improve the magnetic separation process, several tests with different distances between the magnet and the conveyor belt were made (21-31cm). On the other hand, to improve the quality of the produced aggregates, the bar screen size fractions were analyzed, according to the Portuguese Standard (NP EN 933-1 2000). The most efficient distances for the magnetic separation process were identified as between 21 and 27cm, with efficiency between 85% and 90% respectively. According to the histograms, the more frequent red aggregate from 0-4mm size fraction are +0.425-0.850; +0.850-1.7 and +1.7-3.35. From the 4-8mm red aggregates, the more frequent size fractions are +4.75-6.7 and +6.7-9.95. Finally, from the 8-12mm red aggregates, the more frequent new size fractions are +6.7-9.50 and +9.50-13.20. Sieving results obtained from cumulative curves for red aggregate showed an decrease in the mass % amount for the size fractions: 0-4mm: 97%, 4-8mm:76% and 8-12mm: 56%. The results from cumulative curves for grey aggregate showed a light decreased in the amount mass % for the size fractions: 0-4mm: 90%, 4-8mm:56% and 8-12mm: 60%.
Recycling of Exhausted Batteries and EAF Dusts by Leaching with Several Aqueous Media
Authors: Pedrosa Fátima , Cabral Marta , Margarido Fernanda , Nogueira Carlos A.
Published: November 2012

Zinc is a base metal present in several products of general use, and therefore found in numerous residues and end-of-life products. The two main sources of zinc containing wastes are spent Zn-MnO2 portable batteries and electric arc furnace (EAF) dusts from steelmaking plants. The recovery of metals from these residues by appropriate recycling processes is mandatory due to environmental, economic and resource conservation issues. Concerning the similar composition of both residues, their simultaneous processing can be envisaged. The research herein described consists on the hydrometallurgical treatment of zinc bearing waste, where several leaching routes for solubilising metals, mainly zinc, are studied. The leaching of shredded batteries and EAF dusts was carried out using three different leaching solutions containing sulfuric acid, hydrochloric acid or ammonium chloride. The acid leaching of zinc in the oxide form (zincite) using both acids, was very efficient and quick, allowing the recovery of practically all Zn contained in batteries and about of 80% of Zn in dusts. Regarding to the leaching media the behaviour of lead oxides present in dusts was different, being insoluble with H2SO4 and partially soluble with HCl (40-90% yield, depending on conditions). For battery waste stream, manganese is also other important metal, which oxides were only partially soluble in acid media, attaining a maximum leaching yield of 90% Mn. Iron, considered a contaminant in both residues, was partially leached and required further purification steps. The use of an ammoniacal medium (NH4Cl) was very selective for zinc, being iron practically insoluble. However, the maximum zinc leaching yield attained for both residues was only near 60%. Under these conditions, manganese contained in batteries was very insoluble while lead from dusts was leached up to 70% due to the relative solubility of lead chloride. This research showed that hydrometallurgical treatment can provide versatile solutions for recycling metals from Zn waste. Ammoniacal leaching allows high selectivity for zinc but less recovery efficiency is attained, while acid leaching allows higher metal recovery yields but unwanted elements like iron are co-dissolved.
Valorisation of Rice Husk by Chemical and Thermal Treatments
Authors: Madrid Rosário , Margarido Fernanda , Nogueira Carlos A.
Published: November 2012

In the industrial production of rice, large quantities of rice husk are generated constituting a residue with costs for the companies, which must be appropriately managed. The high grade of silica in the rice husk opens a possibility for its valorisation, through the production of amorphous silica with high porosity and potential application as ligand in construction materials, as catalyst support, as metals adsorbent, among others. In this research work a process was developed for the production of silica with amorphous properties from rice husk waste, and the products formed were characterised. The process involved three main operations: water washing for removal of some impurities, acid leaching with HCl or H2SO4 solutions for dissolution of contaminating metals and incineration for organics decomposition. The washing operation let a partial purification of the husk, allowing removal of 46-60% of contaminating metals such as K, Fe Mn and Zn. The leaching with 0.4M HCl and 0.2M H2SO4 allowed obtaining high metals removal efficiency, namely >99% for potassium, 85-90% for iron, >96% for manganese and >80% for zinc. The final composition of the leached husk was 0.003-0.006% K, 0.016-0.025% Fe, <0.001% Mn and <0.0007% Zn. The incineration of the rice husk after previous purification was performed at 540°C, by using samples obtained in the several chemical treatment conditions, and using different heating and cooling rates. As a result, a white colored final husk ash was produced, rich in quasi-amorphous silica (confirmed by X-ray diffraction). The analysis by scanning electron microscopy revealed that the organics removal allowed the formation of voids in the rice husk material, which became very porous and presented an alveolar morphology.
Waste Marble Dust Blended Cement
Authors: Grilo Maria J. , Pereira João , Costa Carla
Published: November 2012

Marble processing activities generates a significant amount of waste in dust form. This waste, which is nowadays one of the environmental problems worldwide, presents great potential of being used as mineral addition in blended cements production. This paper shows preliminary results of an ongoing project which ultimate goal is to investigate the viability of using waste marble dust (WMD), produced by marble Portuguese industry, as cement replacement material. In order to evaluate the effects of the WMD on mechanical behaviour, different mortar blended cement mixtures were tested. These mixtures were prepared with different partial substitution level of cement with WMD. Strength results of WMD blended cements were compared to control cements with same level of incorporation of natural limestone used to produce commercial Portland-limestone cements. The results obtained show that WMD blended cements perform better than limestone blended cements for same replacement level up to 20% w/w. Therefore, WMD reveals promising attributes for blended cements production.
Application of Eddy Currents in Processed Materials Structural Evaluation
Authors: Santos Telmo Gomes , Faria João , Vilaça Pedro , Miranda R.M.
Published: November 2012

Eddy currents are based on electromagnetic induction and analysis of electrical currents on conductive materials. This method is used for thickness measurements, corrosion and defects detection, electrical conductivity and magnetic permeability measurements. Recently, it has been exploited as a materials characterization technique, namely in solid state welding, since, compared to hardness, it is based in distinct physical phenomena. Electrical conductivity is controlled by electronic mobility, while hardness depends on crystal defects and thus a scale factor exists. This paper presents results of this characterization technique applied to multipass solid state friction stir processing (FSP) of AA1100 alloy. These results were compared to microstructural analysis and hardness measurements and show that eddy current is a feasibly, reliable and expedite technique to characterize processed materials. The electrical conductivity measured by eddy currents, maps more precisely structural features, while hardness does not. Measurement of electrical conductivity field suggests having potential to constitute an alternative and/or complement to hardness evaluation with the further advantage of being a non-destructive method.
Metallographic Characterization of Friction Stir Channels
Authors: Vidal Catarina , Infante Virgínia , Vilaça Pedro
Published: November 2012

Friction Stir Channelling (FSC) is an innovative technique of manufacturing integral and continuous channels (also referred as conformal channels) in monolithic plates in a single step. The process is capable of producing non-linear channels in solid components with similar control of the parameters applied during Friction Stir Welding. The tool geometry and concept plays a major influence in the results from FSC. During FSC a controlled amount of workpiece material flow-out from the processed zone producing the internal channel. The heat energy that softens the workpiece material is generated from dissipation during plastic deformation, internal viscous dissipation during the material flow and dissipation from frictional work between the tool and the workpiece. This research work is based on a detail metallographic, geometric and hardness analysis of integral and continuous FS channels produced in a monolithic plate of the aluminium alloy AA7178‑T6 with 13mm of thickness, typically used in structural aircraft applications. In this paper the metallographic characterization and the hardness distribution in the processing zone that surrounds the channel are presented and discussed. Channel’s geometric characterization is also presented and discussed. The channel microstructure and its roughness features were obtained using optical microscopy and SEM.
Microstructure and Strength of γ-TiAl Alloy/Inconel 718 Brazed Joints
Authors: Sequeiros Elsa W. , Guedes Anibal , Pinto Ana Maria Pires , Vieira Manuel F. , Viana Filomena
Published: November 2012

Intermetallics and superalloys brazing development is a current topic owing the extending use of these alloys in industrial applications. In this work a γ-TiAl alloy was joined to Inconel 718 by active metal brazing, using Incusil-ABA as filler. Joining was performed at 730 °C, 830 °C and 930 °C, with a 10 min dwelling time. The interfaces were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD). For all processing conditions, the reaction between the base materials and the braze alloy produced multilayered interfaces. For all processing temperatures tested (Ag), (Cu), AlNi2Ti and AlCu2Ti were identified at the interface. Raising the brazing temperature increased the thickness of the interface and coarsened its microstructure. The increase of the extension of the interface was essentially due to the growth of the reaction layers formed near each base material, which were found to be mainly composed of intermetallic compounds. The mechanical behavior of the joints, at room temperature, was assessed by microhardness and shear tests. For all processing conditions the hardness decreases from periphery towards the Ag-rich centre of the joints. Brazing at 730 °C for 10 min produced the joints with the highest average shear strength (228±83 MPa). SEM and EDS analysis of the fracture surfaces revealed that fracture of joints always occurred across the interface, preferentially through the hard layer, essentially composed of AlNi2Ti, resulting from the reaction between Inconel 718 and the braze alloy.
Influence of Graphite and Carbon Nanotubes on the Mechanical and Electrical Properties of Cast Epoxy Composites
Authors: de Souza Clarissa F.M. , Leite Janaina L. , Salmoria Gean V. , Pouzada António Sergio
Published: November 2012

This study evaluates the influence of graphite and multi-wall carbon nanotubes on the mechanical and electric properties of cast epoxy resin. The epoxy resin based composites were prepared with various graphite and MWNCT content up to 5.0%. Specimens were characterized by DMA, SEM and electric resistivity tests. The observation of fracture surfaces showed a reasonable dispersion of graphite and MWCNT into the epoxy matrix. The graphite and MWCNT have almost the same effect in the electric conductivity of the epoxy composites at low content (0.2 and 0.5 %). The MWCNT composites seem to reach percolation at concentrations near 0.5 % whereas graphite composites reach it at 2%. Higher concentration of graphite and MWCNT have limited effect in the electric conductivity but reduces mechanical properties.
Infrared Nanosecond Laser Radiation in the Creation of Gold and Copper Nanoparticles
Authors: Coelho João M.P. , Silva Catarina , Ruivo Andreia , de Matos António Pires
Published: November 2012

Metal nanoparticles inside glass present useful properties to photonic applications and have been object of several research works. In particular, laser beams have shown their potential in its creation and both ultraviolet beams with nanosecond pulses, and near-infrared beams with femtosecond pulses, have been used. In this paper, the authors add new possibilities by experimentally demonstrating that it is possible to achieve the same results by using near-infrared laser beams and nanosecond pulses. Copper and gold nanoparticles are created in silica-doped glass using nanosecond laser pulses in the near-infrared. Recorded absorption spectra of the glass samples before, and after laser irradiation and further annealing allowed measuring absorption peaks located at 537 nm for copper and 563 nm for gold, which are in accordance with the expected values. Based on Mie theory and using the full-width half maximum for those peaks, the average particle radii of the embedded nanoparticles was estimated to be about 7 nm for copper and 3 nm for gold nanoparticles, respectively.
Studies of the Performance of Nanostructured and other Compatible Consolidation Products for Historical Renders
Authors: Borsoi Giovanni , Tavares Martha , Veiga R. , Santos Silva António
Published: November 2012

This work is inserted in a wider project aiming at the conservation and durability of historical renders, through compatibles techniques and materials; in particular the restitution of cohesion of historical renders, turned friable by the loss of binder due to physical or chemical actions, is studied. Surface consolidation, directed to restore cohesion and stability, is based on the use of materials with aggregating properties. This operation is reached usually through the application of organic or mineral consolidants, but inorganic consolidants (such as calcium hydroxide or ethyl silicate) are preferred due to better compatibility and durability. Based on the results of previous studies, two mineral compatible products were selected: a commercial suspension of nanoparticles of calcium hydroxide in propanol (Nanorestore); a silicate product, consisting on a limewater dispersion of ethyl silicate. Consolidation products were than applied on different mortars samples previously prepared, in order to assess their efficacy by determining their physical, mechanical and microstructural properties before and after the consolidation treatment. Mechanical and physical analyses were performed, such as compression and flexural strenght and superficial hardness. Microstructural and chemical analyses of the consolidation product and of the consolidated samples are also reported.
Manganese Mono-Substituted Borotungstate: Characterization and Catalytic Application
Authors: Balula Salete S. , Santos Isabel C.M.S. , Barbosa André D.S. , Schlindwein Walkiria , Cavaleiro Ana M.V. , de Castro Baltazar , Cunha-Silva Luís
Published: November 2012

The Keggin-type TBA4H2[BW11Mn(H2O)O39].H2O (BW11Mn) compound was isolated and characterized. The first sphere of coordination for the manganese atom was determined by EXAFS analysis. Six oxygen atoms were found in the range of 1.80-2.64 Å from the manganese. BW11Mn showed to be an active, efficient and selective catalyst for cis-cyclooctene (1a) epoxidation in the presence of stoichiometric quantities of H2O2. After 5 h of reaction almost complete conversion was achieved (86% of conversion). Selectivity was always 100 % for the epoxide.
Epoxide Moisture Absorption Studied by Positron Lifetime Spectroscopy
Authors: Luís J.M.M. , Duarte Naia Marco , Ferreira Marques Maria Fatima , Morais J.J.L. , Gordo P.M.
Published: November 2012

In the last years there have been made several studies, involving many materials, with the aim of trying to explain some physical, chemical and mechanical macroscopic properties of these materials, across the study of the free volumes at the atomic and molecular scale. The positron annihilation lifetime spectroscopy (PALS) is one of the most widely used in this type of studies, and it was here used to characterize the free volumes fraction of a commercial epoxy and trying to understand the mechanism associated with the process of moisture absorption which leads to an increase of mass and volume on this commercial epoxy.
Salient stakeholder voices: Family business and green innovation adoption
Authors: Huang Yi-Chun , Ding Hung-Bin , Kao Ming-Rea
Published: November 2012

One striking finding from recent natural environmental management research is that family firms are more likely to engage in environmentally friendly practices. However, the source of such difference is less clear. The primary objective of our research is to investigate if family firms react to stakeholder pressures differently when making natural environmental management decisions. We survey 235 manufacturing firms from the chemical, and the electronic and information technology industries in Taiwan to test our hypotheses. The results of regression analysis show that family firms pay much more attention to their internal stakeholders than non-family firms. This finding complements the current discussions on family business uniqueness. It also contributes to provide a more comprehensive framework of stakeholder salience.
Do families shape corporate governance structures?
Authors: Navarro María Sacristán , Ansón Silvia Gómez
Published: November 2012

This paper provides empirical evidence of family firm corporate governance structures, by examining a set of corporate governance characteristics of 132 non-financial Spanish listed firms. Results show that family firm boards present differential characteristics and that different patterns of family ownership configurations do not affect family firm corporate governance structures. We find that Spanish family firm boards are smaller than those in non-family firms. Family firm directors own a larger fraction of firm shares and have longer Chairman tenure than non-family firms, and family firms use fewer voluntary board committees – such as nomination and remuneration committees and executive committees. Besides, family firm boards and committees are biased towards insiders. Whether these differential characteristics affect other minority non-family shareholders negatively remains an open question.
Attitudes and expectations of shareholders: The case of the multi-generation family business
Authors: Thomas Jill
Published: November 2012

As family shareholder support is essential for the ongoing viability of the business as a family business, multi-generation family businesses which allow ‘the ownership tree’ to grow need to monitor the attitudes and expectations of the expanding number of family member shareholders. This paper reports on a case study of a multi-generation family business where the shareholder group had grown to 50 individual shareholders. The study explored the shareholders' views about the business and particularly their attitudes to stewardship and whether and under what circumstances, they would hold their shareholdings, pass them to the next generation of family or possibly consider relinquishing their holdings. Data was obtained from a semi-structured questionnaire and follow-up interviews. While respondents indicated that they had immense pride in being a shareholder of the family business, they admitted that their knowledge of that business was less than optimal. Financial returns were viewed as important, but the intangible rewards relating to the heritage of forebears were more so. While they were keen to pass on their shares to their children, they were uncertain about the level of commitment the next generation members would have. Lessons from this case study are discussed for other multi-generation family businesses focusing on shareholders' responsibilities as owners and the board's need to ensure timely transfer of knowledge to the wider shareholder group.
A Tropospheric Emission Spectrometer HDO/H2O retrieval simulator for climate models
Authors: Field R. D. , Risi C. , Schmidt G. A. , Worden J. , Voulgarakis A. , LeGrande A. N. , Sobel A. H. , Healy R. J.
Published: November 2012

Abstract. Retrievals of the isotopic composition of water vapor from the Aura Tropospheric Emission Spectrometer (TES) have unique value in constraining moist processes in climate models. Accurate comparison between simulated and retrieved values requires that model profiles that would be poorly retrieved are excluded, and that an instrument operator be applied to the remaining profiles. Typically, this is done by sampling model output at satellite measurement points and using the quality flags and averaging kernels from individual retrievals at specific places and times. This approach is not reliable when the model meteorological conditions influencing retrieval sensitivity are different from those observed by the instrument at short time scales, which will be the case for free-running climate simulations. In this study, we describe an alternative, "categorical" approach to applying the instrument operator, implemented within the NASA GISS ModelE general circulation model. Retrieval quality and averaging kernel structure are predicted empirically from model conditions, rather than obtained from collocated satellite observations. This approach can be used for arbitrary model configurations, and requires no agreement between satellite-retrieved and model meteorology at short time scales. To test this approach, nudged simulations were conducted using both the retrieval-based and categorical operators. Cloud cover, surface temperature and free-tropospheric moisture content were the most important predictors of retrieval quality and averaging kernel structure. There was good agreement between the δD fields after applying the retrieval-based and more detailed categorical operators, with increases of up to 30‰ over the ocean and decreases of up to 40‰ over land relative to the raw model fields. The categorical operator performed better over the ocean than over land, and requires further refinement for use outside of the tropics. After applying the TES operator, ModelE had δD biases of −8‰ over ocean and −34‰ over land compared to TES δD, which were less than the biases using raw model δD fields.
Spectral absorption of biomass burning aerosol determined from retrieved single scattering albedo during ARCTAS
Authors: Corr C. A. , Hall S. R. , Ullmann K. , Anderson B. E. , Beyersdorf A. J. , Thornhill K. L. , Cubison M. J. , Jimenez J. L. , Wisthaler A. , Dibb J. E.
Published: November 2012

Abstract. Actinic flux, as well as aerosol chemical and optical properties, were measured aboard the NASA DC-8 aircraft during the ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) mission in Spring and Summer 2008. These measurements were used in a radiative transfer code to retrieve spectral (350–550 nm) aerosol single scattering albedo (SSA) for biomass burning plumes encountered on 17 April and 29 June. Retrieved SSA values were subsequently used to calculate the absorption Angstrom exponent (AAE) over the 350–500 nm range. Both plumes exhibited enhanced spectral absorption with AAE values that exceeded 1 (6.78 ± 0.38 for 17 April and 3.34 ± 0.11 for 29 June). This enhanced absorption was primarily due to organic aerosol (OA) which contributed significantly to total absorption at all wavelengths for both 17 April (57.7%) and 29 June (56.2%). OA contributions to absorption were greater at UV wavelengths than at visible wavelengths for both cases. Differences in AAE values between the two cases were attributed to differences in plume age and thus to differences in the ratio of OA and black carbon (BC) concentrations. However, notable differences between AAE values calculated for the OA (AAEOA) for 17 April (11.15 ± 0.59) and 29 June (4.94 ± 0.19) suggested differences in the plume AAE values might also be due to differences in organic aerosol composition. The 17 April OA was much more oxidized than the 29 June OA as denoted by a higher oxidation state value for 17 April (+0.16 vs. −0.32). Differences in the AAEOA, as well as the overall AAE, were thus also possibly due to oxidation of biomass burning primary organic aerosol in the 17 April plume that resulted in the formation of OA with a greater spectral-dependence of absorption.
Influence of the Arctic Oscillation on the vertical distribution of clouds as observed by the A-Train constellation of satellites
Authors: Devasthale A. , Tjernström M. , Caian M. , Thomas M. A. , Kahn B. H. , Fetzer E. J.
Published: November 2012

Abstract. The main purpose of this study is to investigate the influence of the Arctic Oscillation (AO), the dominant mode of natural variability over the northerly high latitudes, on the spatial (horizontal and vertical) distribution of clouds in the Arctic. To that end, we use a suite of sensors onboard NASA's A-Train satellites that provide accurate observations of the distribution of clouds along with information on atmospheric thermodynamics. Data from three independent sensors are used (AQUA-AIRS, CALIOP-CALIPSO and CPR-CloudSat) covering two time periods (winter half years, November through March, of 2002–2011 and 2006–2011, respectively) along with data from the ERA-Interim reanalysis. We show that the zonal vertical distribution of cloud fraction anomalies averaged over 67–82° N to a first approximation follows a dipole structure (referred to as "Greenland cloud dipole anomaly", GCDA), such that during the positive phase of the AO, positive and negative cloud anomalies are observed eastwards and westward of Greenland respectively, while the opposite is true for the negative phase of AO. By investigating the concurrent meteorological conditions (temperature, humidity and winds), we show that differences in the meridional energy and moisture transport during the positive and negative phases of the AO and the associated thermodynamics are responsible for the conditions that are conducive for the formation of this dipole structure. All three satellite sensors broadly observe this large-scale GCDA despite differences in their sensitivities, spatio-temporal and vertical resolutions, and the available lengths of data records, indicating the robustness of the results. The present study also provides a compelling case to carry out process-based evaluation of global and regional climate models.
Improved Micro Rain Radar snow measurements using Doppler spectra post-processing
Authors: Maahn M. , Kollias P.
Published: November 2012

Abstract. The Micro Rain Radar 2 (MRR) is a compact Frequency Modulated Continuous Wave (FMCW) system that operates at 24 GHz. The MRR is a low-cost, portable radar system that requires minimum supervision in the field. As such, the MRR is a frequently used radar system for conducting precipitation research. Current MRR drawbacks are the lack of a sophisticated post-processing algorithm to improve its sensitivity (currently at +3 dBz), spurious artefacts concerning radar receiver noise and the lack of high quality Doppler radar moments. Here we propose an improved processing method which is especially suited for snow observations and provides reliable values of effective reflectivity, Doppler velocity and spectral width. The proposed method is freely available on the web and features a noise removal based on recognition of the most significant peak. A dynamic dealiasing routine allows observations even if the Nyquist velocity range is exceeded. Collocated observations over 115 days of a MRR and a pulsed 35.2 GHz MIRA35 cloud radar show a very high agreement for the proposed method for snow, if reflectivities are larger than −5 dBz. The overall sensitivity is increased to −14 and −8 dBz, depending on range. The proposed method exploits the full potential of MRR's hardware and substantially enhances the use of Micro Rain Radar for studies of solid precipitation.
Implementation of multirate time integration methods for air pollution modelling
Authors: Schlegel M. , Knoth O. , Arnold M. , Wolke R.
Published: November 2012

Abstract. Explicit time integration methods are characterised by a small numerical effort per time step. In the application to multiscale problems in atmospheric modelling, this benefit is often more than compensated by stability problems and step size restrictions resulting from stiff chemical reaction terms and from a locally varying Courant-Friedrichs-Lewy (CFL) condition for the advection terms. Splitting methods may be applied to efficiently combine implicit and explicit methods (IMEX splitting). Complementarily multirate time integration schemes allow for a local adaptation of the time step size to the grid size. In combination, these approaches lead to schemes which are efficient in terms of evaluations of the right-hand side. Special challenges arise when these methods are to be implemented. For an efficient implementation, it is crucial to locate and exploit redundancies. Furthermore, the more complex programme flow may lead to computational overhead which, in the worst case, more than compensates the theoretical gain in efficiency. We present a general splitting approach which allows both for IMEX splittings and for local time step adaptation. The main focus is on an efficient implementation of this approach for parallel computation on computer clusters.
Estimation of debris flow critical rainfall thresholds by a physically-based model
Authors: Papa M. N. , Medina V. , Ciervo F. , Bateman A.
Published: November 2012

Abstract. Real time assessment of debris flow hazard is fundamental for setting up warning systems that can mitigate its risk. A convenient method to assess the possible occurrence of a debris flow is the comparison of measured and forecasted rainfall with rainfall threshold curves (RTC). Empirical derivation of the RTC from the analysis of rainfall characteristics of past events is not possible when the database of observed debris flows is poor or when the environment changes with time. For landslides triggered debris flows, the above limitations may be overcome through the methodology here presented, based on the derivation of RTC from a physically based model. The critical RTC are derived from mathematical and numerical simulations based on the infinite-slope stability model in which land instability is governed by the increase in groundwater pressure due to rainfall. The effect of rainfall infiltration on landside occurrence is modelled trough a reduced form of the Richards equation. The simulations are performed in a virtual basin, representative of the studied basin, taking into account the uncertainties linked with the definition of the characteristics of the soil. A large number of calculations are performed combining different values of the rainfall characteristics (intensity and duration of event rainfall and intensity of antecedent rainfall). For each combination of rainfall characteristics, the percentage of the basin that is unstable is computed. The obtained database is opportunely elaborated to derive RTC curves. The methodology is implemented and tested on a small basin of the Amalfi Coast (South Italy).
Temporal clustering of the seismicity of the Absheron-Prebalkhan region in the Caspian Sea area
Authors: Telesca L. , Babayev G. , Kadirov F.
Published: November 2012

Abstract. The historical and instrumental catalog of the Absheron-Prebalkhan region in the Caspian Sea area was analyzed in order to reveal the existence of temporal clustering in the time dynamics of the seismicity. The timespan of the catalog is from 1842 to 2012 and the magnitude of the events ranges from 2.5 to 6.8. The Gutenberg-Richter analysis indicates 4.0 as the completeness magnitude of the catalog. The temporal clustering analysis was performed over the sequence of events with magnitude M ≥ 4 by using the methods of the Allan Factor and the coefficient of variation. Both the methods have revealed the presence of time-clusterized structures in the time dynamics of large events in the Absheron-Prebalkhan region. Such findings, which suggest a non-Poissonian behavior of the seismicity of the investigated area, could contribute to a deeper knowledge of the time dynamics of the seismicity and to a better assessment of the relative seismic hazard.
A comparative analysis of the effectiveness of flood management measures based on the concept of "retaining water in the landscape" in different European hydro-climatic regions
Authors: Salazar S. , Francés F. , Komma J. , Blume T. , Francke T. , Bronstert A. , Blöschl G.
Published: November 2012

Abstract. In this paper, we analyse the effectiveness of flood management measures based on the concept known as "retaining water in the landscape". The investigated measures include afforestation, micro-ponds and small-reservoirs. A comparative and model-based methodological approach has been developed and applied for three meso-scale catchments located in different European hydro-climatological regions: Poyo (184 km2) in the Spanish Mediterranean, Upper Iller (954 km2) in the German Alps and Kamp (621 km2) in Northeast-Austria representing the Continental hydro-climate. This comparative analysis has found general similarities in spite of the particular differences among studied areas. In general terms, the flood reduction through the concept of "retaining water in the landscape" depends on the following factors: the storage capacity increase in the catchment resulting from such measures, the characteristics of the rainfall event, the antecedent soil moisture condition and the spatial distribution of such flood management measures in the catchment. In general, our study has shown that, this concept is effective for small and medium events, but almost negligible for the largest and less frequent floods: this holds true for all different hydro-climatic regions, and with different land-use, soils and morphological settings.
Complete synchronization of chaotic atmospheric models by connecting only a subset of state space
Authors: Hiemstra P. H. , Fujiwara N. , Selten F. M. , Kurths J.
Published: November 2012

Abstract. Connected chaotic systems can, under some circumstances, synchronize their states with an exchange of matter and energy between the systems. This is the case for toy models like the Lorenz 63, and more complex models. In this study we perform synchronization experiments with two connected quasi-geostrophic (QG) models of the atmosphere with 1449 degrees of freedom. The purpose is to determine whether connecting only a subset of the model state space can still lead to complete synchronization (CS). In addition, we evaluated whether empirical orthogonal functions (EOF) form efficient basis functions for synchronization in order to limit the number of connections. In this paper, we show that only the intermediate spectral wavenumbers (5–12) need to be connected in order to achieve CS. In addition, the minimum connection timescale needed for CS is 7.3 days. Both the connection subset and the connection timescale, or strength, are consistent with the time and spatial scales of the baroclinic instabilities in the model. This is in line with the fact that the baroclinic instabilities are the largest source of divergence between the two connected models. Using the Lorenz 63 model, we show that EOFs are nearly optimal basis functions for synchronization. The QG model results show that the minimum number of EOFs that need to be connected for CS is a factor of three smaller than when connecting the original state variables.
Combined Scraping, Coagulation, and Subconjunctival Bevacizumab in Descemet Stripping Automated Endothelial Keratoplasty for Bullous Keratopathy
Authors: Chiang Chun-Chi , Lin Jane-Ming , Tsai Yi-Yu
Published: November 2012

Purpose

This study evaluated the clinical outcomes of a combined method of scraping corneal epithelium, coagulating vessels, and subconjunctival bevacizumab in Descemet stripping automated endothelial keratoplasty (DSAEK) for bullous keratopathy with corneal neovascularization (NV).

Methods

The study included patients with bullous keratopathy undergoing DSAEK. Indications for DSAEK were advanced pseudophakic bullous keratopathy with superficial and deep corneal vascularization and failed corneal grafts. Patients were treated by scraping the corneal epithelium and lightly coagulating the corneal superficial stromal NV and the feeding vessels in the sclera, with a subconjunctival bevacizumab injection at the end of surgery. Subconjunctival and perilimbal bevacizumab dose of 2.5 mg/0.1 mL/affected quadrant was injected at the site of NV in each patient at the end of surgery. One or 2 injections were applied. At each visit, a full eye examination with photographic documentation was performed. Mean follow-up period was 32 ( 24 – 36 ) months.

Results

Eight eyes of 8 patients with high-risk corneal transplantation and corneal NV were included in this noncomparative interventional case series. The original corneal NV disappeared in all patients immediately after surgery. No patient in the series had recurrent corneal NV or rejection during at least 24 months of follow-up.

Conclusions

The combination of scraping, coagulating, and bevacizumab injection in DSAEK is an effective method to treat corneal NV in corneal transplantation for bullous keratopathy.
RADON U VODAMA SEIZMIČKI AKTIVNIH ZONA TUZLANSKE REGIJE
Authors: Spona Uzeir
Published: November 2012

Već više od trideset godina traju istraživanja na temu naglih promjena (iznenadnog povećanja ili smanjenja) koncentracije radona koja prethodi zemljotresu na određenoj lokaciji U ovom radu prikazani su rezultati mjerenja koncentracije aktivnosti radona u vodama seizmički aktivnih zona Tuzlanske regije. Korištena je i opisana metoda mjerenja radona u vodi pomoću AlphaGUARD mjernog sistema kao i metodologija uzorkovanja vode iz jezera Modrac te bunara i izvorišta na području seizmički aktivnih zona Tuzlanske regije. Dobiveni rezultati uspoređeni su s referentnim vrijednostima iz literature te su procijenjene doze kao i rizici za zdravlje ljudi koji žive nad seuzmički aktivnim zonama Tuzlanske regije.
OPTIMAL ENERGY EFFICIENT BUILDING DESIGN USING IMPROVED EVOLUTIONARY ALGORITHM
Authors: Pejičić Goran , Vrbanac Miloš , Vukadinović Milenko
Published: November 2012

Considering energy efficiency and sustainable development on one side and economy aspects on the other, optimal building design has to meet two confronted demands: to minimize total cost of the construction and to minimize energy consumption, which is usually obtained by implementation of expensive insulation and equipment. This paper presents solving methodology using evolutionary algorithm improved by introducing the tabu search module and combined with EnergyPlus software. The results are demonstrated on the example of optimization of insulation materials and orientation angle of a given building, confirming that proposed methodology successfully meets design demands.
NULTO STANJE KVALITETA VAZDUHA U PODRUČJU KORIDORAVc
Authors: Đurić Neđo , Babić Radenko , Đuran Perica , Savković Petar , Vidaković Mira
Published: November 2012

Koridor Vc je dio evropske mreže kopnenih koridora koji predstavlja vezu sa Jadranskim morem, ide od Budimpešte preko Osijeka i Sarajeva do luke Ploče u Hrvatskoj. Kroz Bosnu i Hercegovinu prolazi sredinom zemlje u dužini od 330 km. Prije nego što se pristupi izgradnji neophodno je odrediti stanje zagađenosti vazduha odnosno, nulto stanje da bi se kasnije imala realna slika o uticaju saobraćaja na kvalitet vazduha u toku eksploatacije autoputa. U radu su prikazani rezultati mjerenja aerozagađenja koji će biti osnova za dalju ocjenu kvaliteta vazduha kada se autoput stavi u funkciju.
SANACIJA OTPADNIH VODA IZ UPRAVNO POGONSKE ZGRADE RMU „SOKO“ – ČITLUK
Authors: Kokerić Slobodan , Guberinić Rade , Miljanović Jovo
Published: November 2012

Rudnik „Soko“ – Čitluk je izgradio i polovinom 2006. godine pustio u pogon novu upravno pogonsku zgradu površine 2.500 m2 . Nova zgrada po kakcitetu i funkcinalnosti u potpunosti zadovoljava potrebe za preko 600 zaposlenih radnika. Imajući u vidu lokaciju pomenute zgrade kao i činjenicu da se rudnik nalazi na teritoriji prve ekološke opštine u Srbiji, rudnik je vodio računa o očuvanju životne sredine i izgradio sistem za prečišćavanje otpadnih voda pre ispuštanja u recepijent reku Izgaru. U ovom radu prikazaćemo sistem za preradu otpadnih voda, rezultate ispitivanja otpadnih voda pre i posle sistema za preradau otpadnih voda kao i ukupne količine prerađenog efluenta iz postrojenja za konačnu dispoziciju otpadnih voda u recipijent reku „Izgaru“ u 2011. godini.
ANALITIČKI HIJERARHIJSKI POSTUPAK PROCJENE POGODNOSTI KREČNJAKA ZA ODSUMPORAVANJE U TERMOELEKTRANAMA
Authors: Isabegović Jasmin , Šabović Almir , Okanović Hasan
Published: November 2012

U ovom radu je predstavljena metodologija odabira najpovoljnijih ležišta krečnjaka čija bi se sirovina koristila u procesu odsumporavanja u budućim termoenergetskim objektima u Bosni i Hercegovini. Višekriterijski postupak donošenja odluke je razvijen korištenjem analitičkog hijerarhijskog postupka ocjene (AHP). AHP je opsežan, logičan i struktuiran proces razmišljanja, i veoma koristan u rješavanju problema, koji imaju više kriterija koje treba uzeti u obzir. Proces donošenja odluke kao i korišteni kriteriji i subkriteriji predstavljeni su kroz primjere rađene u okviru različitih studija za nove blokove u termoelektranama Tuzla i Kakanj od strane Rudarskog instituta Tuzla.