bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Solution of Frictional Contact Problems for Viscoelastic Solids by SGBEM and Quadratic Programming
Authors: Vodička Roman , Mantič Vladislav
Published: February 2016

The contact problem with Coulomb friction together with a simple Kelvin-Voigt viscoelastic model is studied. The numerical solution is obtained using a time discretization by a semi-implicit formula, the visco-elastic solids in contact being discretized by Symmetric Galerkin Boundary Element Method (SGBEM). The resulting minimization problem with a nonsmooth cost functional is suitably transformed in several ways. Firstly, a transformation is performed to apply SGBEM without any viscoelastic fundamental solution. Secondly, a transformation of contact quantities leads to a minimimization with a quadratic programming structure. Numerical examples show the applicability of the proposed approach to solve rather intricate frictional contact problems.
Contact Modeling of the Duct-Concrete Interface in the Evaluation of Multistrand Effect in High Curvature Post-Tensioned Tanks
Authors: Medina-Reguera Fernando , Cifuentes-Bulté Héctor , Medina-Encina Fernando
Published: February 2016

Post-tensioned tanks for nuclear and energy storage applications are small radius cylindrical concrete structures in most cases. A large pre-compression force must be applied to withstand the high levels of tension produced by both the inner pressure and the temperature gradient between the inner and outer faces of the wall (regardless of the inhomogeneous material alteration due to the latter). Hence, high curvature horizontal (circumferential) tendons with a large number of strands, heavily post-tensioned, must be placed with the smallest possible vertical separation. The resultant radial post-tensioning force is transmitted to the net concrete section through its interface with the duct. The strands however pile up pushing inside the duct producing vertical pressure components along an arc, as well as the flattening out of the duct. The duct detaches then of the concrete leading to a crack initiation. This study presents a strongly non-linear model that attempts to account for all these factors. The results show that the concrete-duct contact must be modeled in order to prevent a crack sewing effect that may greatly overestimate the section capacity to withstand the post-tensioning, not to say the service mechanical and thermal loads. It also shows that these structures require higher tensile concrete strengths, and Ultra High Performance Concrete and Ultra High Performance Fiber Reinforced Concrete must be considered in order to make these tanks viable.
Influence of the Main Contact Parameters in Finite Element Analysis of Elastic Bodies in Contact
Authors: Hattori Gabriel , Serpa Alberto Luiz
Published: February 2016

One of the key issues in solving contact problems is the correct choice of the contact parameters. The contact stiffness, the penetration limit and the contact algorithm are some of the parameters that have to be adjusted. There are no methodologies available in the literature for choosing the contact parameters, relying only on the user experience for this important task. In this work we investigate how the contact parameters behave in a commercial finite element analysis software. We will show that while the contact stiffness has great influence on the finite element analysis, other parameters will not affect it significantly. Some contact examples are shown to illustrate the performance of the contact parameters during the solution of a contact problem.
The Effect of Deformation on Microstructure of Cu-Ni-Sn Aging Alloys
Authors: Thi Chieu Le , Thang Sai Manh , Nam Nguyen Duong , Khanh Pham Mai
Published: February 2016

This paper presents the effect of deformation on the change of microstructure of Cu-15Ni-8Sn and Cu-9Ni-6Sn alloy during heat treatment. The samples were homogenized, quenched, cold-rolled at different thickness reduction, and aged. The effects of deformation on microstructures were observed by optical microscope and SEM. The spinodal decomposition after homogenized solid solution, deformation and aging of these alloys was observed. The results have shown that during aging, from the rich-tin zones formed by spinodal decomposition, produced phase γ. The microstructure included of α +γ. The deformation accelerated the aging process and rapid increased the diameter of formed phase γ.
Study on Rheo-Continuous Casting of Al-Si A356 (EN AC4200) Alloys
Authors: Minh Duc Do , Hai Nguyen Hong
Published: February 2016

Rheo-continuous casting method is a combination of rheo- and continuous castings. In rheo-casting process the nucleation occurs on cooling slope with high rate in whole casting volume, so nuclei are numerous, resulting in very fine microstructure of nodular crystals. In this work the rheo-continuous process was carried out with a casting machine using 2 rollers of same size: diameter of 300 mm and width of 100 mm. The pouring temperature is near-liquidus. The microstructure obtained is fine (grain size < 40 μm), with nodular morphology. The mechanical properties of as-cast samples were high (the tensile strength is above 220 MPa).
Influence of the Ageing Temperature on the Microstructure and Selected Mechanical Properties of Ti13Nb13Zr Alloy
Authors: Dąbrowski Robert , Krawczyk Janusz , Rożniata Edyta
Published: February 2016

Investigation results concerning changes occurring in the microstructure of the near β titanium alloy, grade: Ti13Nb13Zr, when the ageing temperature was changed within the range 350÷650°C, are presented in the paper. These changes were assessed on samples previously quenched in water from the selected soaking temperature in the single-phase β range (800°C). Microstructures were investigated by means of the optical microscopy and scanning electron microscopy (SEM). Phases occurring in the alloy at various ageing temperatures were identified with using the XRD analysis. Microstructure investigations were supplemented by hardness measurements by means of the Vickers apparatus, type HP0 250. In addition, for the selected ageing temperatures, the Charpy impact tests were performed on the Ti13Nb13Zr alloy samples. These tests were carried out on the Charpy tester of a potential energy of 150 J. The results of Charpy impact tests were supported by the fractographic documentation of samples fractures. The fractographic investigations were performed by means of the scanning electron microscope NovaNanoSEM 450.The obtained results constitute the valuable supplementation of the data bases concerning microstructures and mechanical properties of near β titanium alloys.
The Structure and Mechanical Properties of Plastically Consolidated Al-Ni Alloy
Authors: Włoch Grzegorz , Skrzekut Tomasz , Sobota Jakub , Woźnicki Antoni , Cisoń Justyna
Published: February 2016

Mixed and preliminarily consolidated powders of aluminium and nickel (90 mass % Al and 10 mass % Ni) were hot extruded. As results the rod, 8 mm in diameter, was obtained. As-extruded material was subjected to the microstructural investigations using scanning electron microscopy (SEM/EDS) and X-ray analysis (XRD). The differential scanning calorimetry (DSC) and thermo-mechanical analysis (TMA) were also performed. The mechanical properties of as extruded material were determined by the tensile test and Vickers hardness measurements. In order to evaluate the thermal stability of PM alloy, samples were annealed at the temperature of 475 and 550 °C. After annealing Vickers hardness measurements and tensile tests were carried out. The plastic consolidation of powders during extrusion was found to be very effective, because no pores or voids were observed in the examined material. The detailed microstructural investigations and XRD analyses did not reveal the presence of the intermetallic phases in the as-extruded material. During annealing, the Al3Ni intermetallic compound was formed as the result of chemical reaction between the alloy components. The hardness of the alloy after annealing at the temperature of 475°C was found to be comparable to the hardness in as-extruded state. Annealing of the material at the temperature of 550°C results in hardness decreasing by about 50%, as the consequence of porosity formation and Al3Ni cracking.
Copper Metal Matrix Composites Reinforced by Titanium Nitride Particles
Authors: Wąsik Mateusz , Karwan-Baczewska Joanna
Published: February 2016

Copper based Metal Matrix Composites are promising materials for electrical and electrotechnical applications such as electronic packaging and contacts, resistance welding electrodes, heat exchangers etc. Introducing the ceramics particles into the copper matrix allows to achieve a higher mechanical properties comparing to pure copper. The literature shows the variety of reinforcement materials are used. The most commonly strengthening phase include: oxides Al2O3,Y2O3, SiO2, carbides SiC, WC, TiC, ZrC, borides TiB2, ZrB2 and others such us volcanic tuff, carbon or intermetalic phases Al-Fe. [1-7]. It is obvious that reinforcement material without TiN leads to decrease the electrical conductivity of copper. Preliminary investigations concerning nanoscale Cu-based composites with TiN particles were presented in papers [10, 11]. Powder metallurgy (PM) process leads to obtain uniform distribution of strengthening phase in matrix. In order to achieve uniform distribution the process parameters such as mixing and selection the sizes of particles must be appropriate selected. The another factor of decreasing the mechanical and electrical properties by using PM route is porosity. Conventional PM process includes pressing and sintering does not always allow to achieve the high density what is one of the main criterion for high electrical conductivity material. The hard ceramic particles in metal matrix which are not deformable make difficult the densification process. In some cases the use of more advanced methods of production is desirable. The use of titanium nitride particles is justified by their high electrical conductivity in compare to the other reinforcement materials.
Hydrometallurgical Treatment of Smelted Low-Grade WEEE in Ammoniacal Solutions
Authors: Rudnik Ewa , Dobosz Iwona , Fitzner Krzysztof , Miazga Zbigniew
Published: February 2016

Hydrometallurgical routes of copper recovery from smelted low-grade e-waste are presented. Electronic scrap was smelted to produce Cu–Zn–Ag-Sn alloys of various phase compositions. The alloys were then treated in the following ways: (a) anodic dissolution with simultaneous metal electrodeposition using ammoniacal solutions with various ammonium salts (chloride, carbonate, sulfate). This resulted in the separation of metals, where lead, silver and tin accumulated mainly in the slimes, while copper was transferred to the slime, electrolyte and then recovered on the cathode. (b) leaching in ammoniacal solutions of various compositions and then copper electrowinning. Alloy was leached in chloride, carbonate, sulfate and thiosulfate baths. This resulted in the separation of the metals, wherein copper and zinc were transferred to the electrolyte, while metallic tin and silver as well as lead remained in the slimes. Copper was selectively recovered from the ammoniacal solutions by the electrolysis, leaving zinc ions in the electrolyte. The best conditions of the alloy treatment were obtained, where the final product was copper of high purity (99.9%) at the current efficiency of 60%. Thiosulfate solution was not applicable for the leaching of the copper alloy due to secondary reactions of the formation of copper(I) thiosulfate complexes and precipitation of copper(I) sulfide.
Plastometric Testing of Rheological Properties of 5083 and 5754 Aluminium Alloy
Authors: Sawicki Sylwester , Kawałek Anna , Laber Konrad Błażej , Dyja Henryk , Borowski Jacek , Lesniak Dariusz , Jurczak Henryk
Published: February 2016

The paper present a method for determining the real steel work-hardening curves based on the cylindrical specimen compression test. The subject of testing were 5083 and 5754 aluminium alloy. The tests were carried out using the physical simulator of metallurgical processes GLEEBLE 3800 (Figure 1a) for the temperature range of 400 ÷ 560 °C and the strain rate range of 0,1 - 1,0s-1. Based on plastic deformation parameters recorded during the experiment, mathematical processing, that is the digital filtration and approximation of the obtained testing results, will be performed. Then, using the inverse method, the actual values of the coefficients of the numerical models for the rheological properties of the tested materials will be determined.
Microstructure and Creep Properties of Selected Gravity Casting Magnesium Alloys
Authors: Rzychoń Tomasz
Published: February 2016

In this paper microstructure and creep properties of Mg-Al-Ca-Sr, Mg-Zn-RE-Zr and Mg-Sn-Si gravity casting magnesium alloys are presented. The microstructure was characterized using light microscopy, scanning and transmission electron microscopy. Phase identification was made by SAED and XRD analysis. Creep tests were carried out in the temperature range from 180°C to 200°C at applied stress of 60 MPa. Microstructure of Mg-Al-Ca-Sr alloys composed of α-Mg grains and C36, C15 and C14 intermetallic compounds in the interdendritic regions. In case of Mg-Zn-RE-Zr alloys the dominant intermetallic compound is (Mg,Zn)12RE phase also located in the interdendritic regions. Microstructure of Mg-Sn-Si alloys after T6 heat treatment consists of plate-like precipitates of Mg2Sn phase, primary crystals of Mg2Si phase and globular Mg2Si phase. Among the alloys in this study, the low-cost Mg-5Al-3Ca-0.7Sr alloy has the best creep resistance. The other alloys, excluding the Mg-5Si-7Sn alloy, are characterized by a poorer creep resistance in compared to Mg-5Al-3Ca-0.7Sr alloy, however their creep resistance is better if compared to typical Mg-Al alloys. Creep resistance of Mg-5Si-7Sn alloy is very low.
Changes in Structure and Hardness of CuFe2 Alloy during Rolling with Cyclic Movement of Rolls
Authors: Amrogowicz Piotr , Pawlicki Jacek , Urbańczyk-Gucwa Anna
Published: February 2016

In this article, the results of microstructure and hardness investigation performed on CuFe2 alloy processed by rolling with cyclic movement of rolls (RCMR) were presented. The investigations were focused on cross section planes of deformed samples. This results were compared with the ones obtained for samples after conventional rolling. It was shown that in the initial passes, the additional movement of rolls in RCMR method generate in material heterogeneous microstructure and hardness. With increase of deformation the microstructure and hardness distribution is more homogeneous.
Influence of the Shaping Microstructure Technology and Properties of AlMgSi Alloys on Microcracks Formation under an Influence of Static Compression Loads
Authors: Tarasek Anna , Olszowska Sobieraj Barbara , Stolarska Justyna , Uliasz Piotr
Published: February 2016

Endeavours were undertaken to assess metallographically AlMgSi alloys, (containing 0.58 wt% of Mg, and 0.58 wt% or 6.5 wt% of Si) in their primary states as well as after applying external loads in the Static Compression Test. During the first stage of the study the primary microstructures of the investigated samples were assessed. Samples originated from two technological processes: after strain hardening, in a form of rods (φ 9.5 mm and φ 4.0 mm) gravity casting, rolling, homogenisation and precipitation hardening; and after gravity casting in sand moulds of shaped plates 100 mm x 100 mm x 4 mm of a primary structure and after the precipitation hardening. During the second stage of investigations, microstructures of analysed samples (of various technological history) were compared - after applied external loads - in order to obtain information in what way such diversified primary structure and which of its stereological parameters (amount, shape, size and placement) are essential in initiation of microcracks under static loads.
Representations of Finite Groups
Authors: Chuang Joseph , Geck Meinolf , Linckelmann Markus , Navarro Gabriel
Published: February 2016

The workshop
Representations of Finite Groups
was organised by Joseph Chuang (London), Meinolf Geck (Stuttgart), Markus Linckelmann (London), and Gabriel Navarro (Valencia). It covered a wide variety of aspects of the representation theory of finite groups and related objects, such as algebraic groups.
Copulae: On the Crossroads of Mathematics and Economics
Authors: Chen Xiaohong , Härdle Wolfgang Karl , Jaworski Piotr , Nešlehová Johanna G.
Published: February 2016

The central focus of the workshop was on copula theory as well as applications to multivariate stochastic modelling. The programme was intrinsically interdisciplinary and represented areas with much recent progress. The workshop included talks and dynamic discussions on construction, estimation and various applications of copulas to finance, insurance, hydrology, medicine, risk management and related fields.
Application of the Level-Set Model with Constraints in Image Segmentation
Authors: Klement Vladimír , Oberhuber Tomáš , Ševčovič Daniel
Published: February 2016

We propose and analyze a constrained level-set method for semi-automatic image segmentation. Our level-set model with constraints on the level-set function enables us to specify which parts of the image lie inside respectively outside the segmented objects. Such a-priori information can be expressed in terms of upper and lower constraints prescribed for the level-set function. Constraints have the same conceptual meaning as initial seeds of the popular graph-cuts based methods for image segmentation. A numerical approximation scheme is based on the complementary-finite volumes method combined with the Projected successive over-relaxation method adopted for solving constrained linear complementarity problems. The advantage of the constrained level-set method is demonstrated on several artificial images as well as on cardiac MRI data.
Estudio geométrico de piezas arqueológicas a partir de un modelo virtual 3D
Authors: Mozas Calvache Antonio T. , Pérez García José L. , Barba Colmenero Vicente , López Arenas Andrés
Published: February 2016

This paper describes the methodology for implementing geometric studies of little archaeological artefacts by mean of a 3D virtual model. This model is obtained through laser scanner 3D technology and allows us to obtain high accuracy measures in order to analyze the artefact. The method proposed gives the opportunity for performing these measures in inaccessible zones in the real object, and minimizing the manipulation of the artefact. This aspect is very interesting in order to guarantee its conservation. This methodology has been implemented to a real case: an anthropomorphic feminine idol of around 12 centimetres in length. The results obtained with the measuring of the model allow us to extract important conclusions.
Virtual Hierapolis: tra tecnicismo e realismo
Authors: Gabellone Francesco , Ferrari Ivan , Giuri Francesco , Limoncelli Massimo
Published: February 2016

One of the main activities of MAIER - Italian Archaeological Mission at Hierapolis - has been the development of a research line aimed at the virtual restoration and the three-dimensional restitution of ancient buildings in the roman city of Hierapolis of Phrygia, in Turkey. The project, named "Virtual Hierapolis," has gradually articulated in the last three seasons of excavation (years 2007-2009) and developed from early experiences of Virtual Reality conducted on the same site during previous years. The research, coordinated by the Director of the italian mission, prof. F. D'Andria, and conducted within the Information Technologies Lab (ITLab) of the IBAM-CNR in Lecce, involves heterogeneous research units engaged in field work, restoration and interpretation of data.
Virtual Restoration of Fragmented Glass Plate Photographs of Archaeological Repertoires
Authors: Stanco F. , Tanasi D. , Gallo G.
Published: February 2016

This paper describes a virtual restoration pipeline for the broken glass plates in the fund of the Department of Archaeological, Philological and Historical Studies of Catania University. This archive includes rare images of the excavation activities of the Department in Sicily and Greece. Several of the plates are damaged and fractured and require virtual realignment and restoration. We adapted to this case a restoration algorithm based on the use of image processing techniques. The algorithm enhance the quality of scanned images, and subsequently performs a rigid registration and realignment of the fragments. A final application of inpainting techniques fills the gaps.
Hydroxyl radicals from secondary organic aerosol decomposition in water
Authors: Tong Haijie , Arangio Andrea M. , Lakey Pascale S. J. , Berkemeier Thomas , Liu Fobang , Kampf Christopher J. , Brune William H. , Pöschl Ulrich , Shiraiwa Manabu
Published: February 2016

Abstract. We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (α-pinene, β-pinene, limonene) is  ∼  0.1 % upon extraction with pure water and increases to  ∼  1.5 % in the presence of Fe2+ ions due to Fenton-like reactions. Upon extraction of SOA samples from OH photooxidation of isoprene, we also detected OH yields of around  ∼  0.1 %, which increases upon addition of Fe2+. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical H2O2 Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.
Anthropogenic and biogenic influence on VOC fluxes at an urban background site in Helsinki, Finland
Authors: Rantala Pekka , Järvi Leena , Taipale Risto , Laurila Terhi K. , Patokoski Johanna , Kajos Maija K. , Kurppa Mona , Haapanala Sami , Siivola Erkki , Ruuskanen Taina M. , Rinne Janne
Published: February 2016

Abstract. We measured volatile organic compounds (VOC), carbon dioxide (CO2) and carbon monoxide (CO) at an urban background site near the city centre of Helsinki, Finland, Northern Europe. The VOC and CO2 measurements were obtained between January 2013 and September 2014 whereas for CO a shorter measurement campaign in April–May 2014 was conducted. Both anthropogenic and biogenic sources were identified for VOCs in the study. Strong correlations between VOC fluxes and CO fluxes and traffic rates indicated anthropogenic source of many VOCs. The VOC with highest emission to the atmosphere was methanol which originated mostly from traffic and other anthropogenic sources. Traffic was also a major source for aromatic compounds in all seasons whereas isoprene was mostly emitted from biogenic sources during summer. Small traffic related isoprene emissions were detected during other seasons. Generally, the VOC fluxes were found to be small compared with previous urban VOC flux studies. However, the differences were probably caused by lower anthropogenic activities as the CO2 fluxes were also relatively small at the site.
Evaluation of UTLS carbon monoxide simulations in GMI and GEOS-Chem chemical transport models using Aura MLS observations
Authors: Huang Lei , Jiang Jonathan H. , Murray Lee , Damon Megan , Su Hui , Livesey Nathaniel
Published: February 2016

Abstract. This study evaluates the distribution and variation of carbon monoxide (CO) in the upper troposphere and lower stratosphere (UTLS) during 2004–2012 as simulated by two chemical transport models, using the latest version of Aura Microwave Limb Sounder (MLS) observations. The simulated spatial distributions, temporal variations and vertical transport of CO in the UTLS region are compared with those observed by MLS. We also investigate the impact of surface emissions and deep convection on CO concentrations in the UTLS over different regions, using both model simulations and MLS observations. Global Modeling Initiative (GMI) and GEOS-Chem simulations of UTLS CO both show similar spatial distributions to observations. The global mean CO values simulated by both models agree with MLS observations at 215 hPa and 147 hPa, but are significantly underestimated (> 40 %) at 100 hPa. In addition, the models underestimate the peak CO values by up to 70 % at 100 hPa, 60 % at 147 hPa, and 40 % at 215 hPa, with GEOS-Chem generally simulating more CO at 100 hPa and less CO at 215 hPa than GMI. The seasonal distributions of CO simulated by both models are in better agreement with MLS in the Southern Hemisphere (SH) than in the Northern Hemisphere (NH), with disagreements between model and observations over some enhanced CO regions such as southern Africa. The simulated vertical transport of CO shows better agreement with MLS in the tropics and SH subtropics than NH subtropics. We also examine regional variations in the relationships among surface CO emission, convection and UTLS CO concentrations. The two models exhibit emission-convection-CO relationships similar to those observed by MLS over the tropics and some regions with enhanced UTLS CO.
Oxidative capacity and radical chemistry in the polluted atmosphere of Hong Kong and Pearl River Delta region: analysis of a severe photochemical smog episode
Authors: Xue Likun , Gu Rongrong , Wang Tao , Wang Xinfeng , Saunders Sandra , Blake Donald , Louie Peter K. K. , Luk Connie W. Y , Simpson Isobel , Xu Zheng , Wang Zhe , Gao Yuan , Lee Shuncheng , Mellouki Abdelwahid , Wang Wenxing
Published: February 2016

Abstract. We analyze a multi-day photochemical smog episode to understand the oxidative capacity and radical chemistry of the polluted atmosphere in Hong Kong and the Pearl River Delta (PRD) region. A photochemical box model based on the Master Chemical Mechanism (MCM v3.2) is constrained by an intensive set of field observations to elucidate the budgets of ROX (ROX=OH+HO2+RO2) and NO3 radicals. Highly abundant radical precursors (i.e., O3, HONO and carbonyls), nitrogen oxides (NOX) and volatile organic compounds (VOCs) facilitate strong production and efficient recycling of ROX radicals. The OH reactivity is dominated by oxygenated VOCs (OVOCs), followed by aromatics, alkenes and alkanes. Photolysis of OVOCs (except for formaldehyde) is the dominant primary source of ROX with an average daytime contribution of 47 %. HONO photolysis is the largest contributor to OH and the second most significant source (19 %) of ROX. Other considerable ROX sources include O3 photolysis (11 %), formaldehyde photolysis (10 %), and ozonolysis reactions of unsaturated VOCs (6.2 %). In one case when solar irradiation was attenuated by the high aerosol loadings, NO3 became an important oxidant and the NO3-initiated VOC oxidation presented another significant ROX source (6.2 %) even during daytime. Sensitivity studies show that controlling aromatics is the most efficient way to reduce the atmospheric oxidative capacity and mitigate photochemical pollution in Hong Kong. This study suggests the possible impacts of daytime NO3 chemistry in polluted atmospheres under conditions with the co-existence of abundant O3, NO2, VOCs and aerosols, and also provides new insights into the radical chemistry that essentially drives the formation of photochemical smog in Hong Kong and the PRD region.
The impact of lightning on tropospheric ozone chemistry using a new global parametrisation
Authors: Finney D. L. , Doherty R. M. , Wild O. , Abraham N. L.
Published: February 2016

Abstract. A lightning parametrisation based on upward cloud ice flux is implemented in a chemistry-climate model (CCM) for the first time. The UK Chemistry and Aerosols model is used to study the impact of these lightning nitric oxide (NO) emissions on ozone. Comparisons are then made between the new ice flux parametrisation and the commonly-used, cloud-top height parametrisation. The ice flux approach improves the simulation of lightning and the temporal correlations with ozone sonde measurements in the middle and upper troposphere. Peak values of ozone in these regions are attributed to high lightning NO emissions. The ice flux approach reduces the overestimation of tropical lightning apparent in this CCM when using the cloud-top approach. This results in less emission in the tropical upper troposphere and more in the extratropics when using the ice flux scheme. In the tropical upper troposphere the reduction in ozone concentration is around 5–10 %. Surprisingly, there is only a small reduction in tropospheric ozone burden when using the ice flux approach. The greatest absolute change in ozone burden is found in the lower stratosphere suggesting that much of the ozone produced in the upper troposphere is transported to higher altitudes. Major differences in the frequency distribution of flash rates for the two approaches are found. The cloud-top height scheme has lower maximum flash rates and more mid-range flash rates than the ice flux scheme. The initial Ox (odd oxygen species) production associated with the frequency distribution of continental lightning is analysed to show that higher flash rates are less efficient at producing Ox – low flash rates produce around 10 times more Ox per flash than high-end flash rates. We find that the newly implemented lightning scheme performs favourably compared to the cloud-top scheme with respect to simulation of lightning and tropospheric ozone. This alternative lightning scheme shows spatial and temporal differences in ozone chemistry which may have implications for comparison on models and observations and for simulation of future changes in tropospheric ozone.
Temperature dependence of the relationship between pCO2 and dissolved organic carbon in lakes
Authors: Pinho L. , Duarte C. M. , Marotta H. , Enrich-Prast A.
Published: February 2016

Abstract. The relationship between the partial pressure of carbon dioxide (pCO2) and dissolved organic carbon (DOC) concentration in Brazilian lakes, encompassing 225 samples across a wide latitudinal range in the tropics, was tested. Unlike the positive relationship reported for lake waters, which was largely based on temperate lakes, we found no significant relationship for low-latitude lakes (< 33°), despite very broad ranges in both pCO2 and DOC levels. These results suggest substantial differences in the carbon cycling of low-latitude lakes, which must be considered when upscaling limnetic carbon cycling to global scales.
Modeling precipitation δ18O pariability in East Asia since the Last Glacial Maximum: temperature and amount effects across different time scales
Authors: Wen Xinyu , Liu Zhengyu , Chen Zhongxiao , Brady Esther , Noone David , Zhu Qingzhao , Guan Jian
Published: February 2016

Abstract. Water isotope in precipitation has played a key role in the reconstruction of past climate on millennial and longer timescales. However, for mid-latitude regions like East Asia with complex terrain, the reliability behind the basic assumptions of the temperature effect and amount effect are based on modern observational data and still remains unclear for past climate. In the present work, we re-examine the two basic effects on seasonal, interannual, and millennial timescales in a set of time slice experiments for the period 22 ka thru 00 ka using an isotope-enable AGCM. Our study confirms the robustness of the temperature and amount effects on the seasonal cycle over China, with the temperature effect dominating in northern China, and the amount effect dominating in deep southern China, but no one distinct in the transition region of central China. However, our analysis does not show significant temperature and amount effects over China on millennial and interannual timescales, which is a challenge to those classic assumptions in past climate reconstruction. Our work helps shed light on the interpretation of the proxy record of δ18O from modeling point of view.
Towards thresholds of disaster management performance under demographic change: exploring functional relationships using agent-based modelling
Authors: Dressler G. , Müller B. , Frank K. , Kuhlicke C.
Published: February 2016

Abstract. Effective disaster management is a core feature for the protection of communities against natural disasters such as floods. Disaster management organizations (DMOs) are expected to contribute to ensuring this protection. However, what happens when their resources to cope with a flood are at stake or the intensity and frequency of the event exceeds their capacities? Many cities in the Free State of Saxony, Germany were strongly hit by several floods in the last years and are additionally challenged by demographic change with an ageing society and outmigration leading to population shrinkage in many parts of Saxony. Disaster management which is mostly volunteer-based in Germany is particularly affected by this change, leading to a loss of members. We propose an agent-based simulation model that acts as a "virtual lab" to explore the impact of various changes on disaster management performance. Using different scenarios we examine the impact of changes in personal resources of DMOs, their access to operation relevant information, flood characteristics as well as differences between geographic regions. A loss of DMOs and associated manpower caused by demographic change has the most profound impact on the performance. Especially in rural, upstream regions population decline in combination with very short lead times can put disaster management performance at risk. Based on the results, we outline the implications for research as well as for the practice of disaster management in our concluding section.
Sergančiųjų krūties vėžiu gyvenimo kokybės analizė
Authors: Sąlyga Jonas , Paškevičienė Vitalija , Žiliukas Geriuldas
Published: February 2016

Krūties vėžys – dažniausia moterų onkologinė liga, kuri sudaro apie 32 proc. moterų piktybinių navikų. Susirgus krūties vėžiu blogėja ne tik moters bendra sveikata, bet ir gyvenimo kokybė. Todėl ši tema nepraranda savo aktualumo, kadangi didelis dėmesys turi būti skiriamas sergančiųjų krūties vėžiu gyvenimo kokybės gerinimui. Tyrimo tikslas – įvertinti sergančiųjų krūties vėžiu gyvenimo kokybę. Tyrimo metodika. Atliktas kiekybinis tyrimas. Naudoti instrumentai: anketinė apklausa, kuri sudaryta remiantis standartizuotomis anketomis EORTC QLQ – C30, EORTC QLQ – BR23 bei SF – 36 klausimynu. Taikyta aprašomoji duomenų analizė, naudojant MS Excel 2003 skaičiuoklę. Imtį sudarė – 59 pacientės. Tyrimas atliktas laikantis etikos principų. Tyrimo rezultatai. Nustatyta, kad moterys, sergančios krūties vėžiu, vertindamos savo bendrą gyvenimo kokybę, susijusią su fizine sveikata, labiausiai jautė laisvalaikio (41 proc.), darbo apribojimus dėl fizinių problemų (64 proc.), taip pat daugiausia buvo prastesnis savo sveikatos vertinimas (35 proc.). Atsižvelgiant į respondenčių išsilavinimą, savo sveikatą šiek tiek prasčiau vertino moterys, turinčios aukštesnįjį išsilavinimą. Analizuojant pooperacinio periodo ypatumus gyvenimo kokybei labiausiai moterims pasireiškė kosmetinio defekto sukelti neigiami jausmai (35 proc.), dėl kosmetinio defekto pakitęs gyvenimo būdas (59 proc.), moteriškumo sumažėjimas (24 proc.). Lyginant ištekėjusių ir išsiskyrusių/našlių respondenčių atsakymus į klausimą, ar dėl ligos ir gydymo yra bent kartą pasijutusios mažiau moteriškos, verta pažymėti, jog ištekėjusios moterys kur kas dažniau pasijusdavo mažiau moteriškos negu išsiskyrusios ar našlės. Sergančiųjų krūties vėžiu gyvenimo kokybei įtakos turėjo šie psichoemocinės būklės aspektai: atsiradęs nerimas, baimė dėl ligos atsinaujinimo ir išplitimo (78 proc.), depresija (56 proc.) nepilnavertiškumo jausmas (32 proc.), asmenybės (49 proc.) ir dvasinės būklės pokyčiai (47 proc). Išvada. Sergančiųjų krūties vėžiu gyvenimo kokybei įtakos turi fizinė, dvasinė sveikata, psichoemocinė būklė bei pooperacinis periodas. Todėl ypatingas dėmesys turi būti skiriamas gerinti moterų psichoemocinę būseną ir gyvenimo kokybę.
Dalyvavimas nevyriausybinių organizacijų sveikos gyvensenos ugdyme: asmens holistinės saviugdos dimensijos
Authors: Vaivada Saulius , Žydžiūnaitė Vilma
Published: February 2016

Tyrimo kontekstas: dalyvavimas nevyriausybinių organizacijų (NVO) sveikos gyvensenos ugdyme sukuria palankias sąlygas asmens saviugdai. Sveika gyvensena kaip saviugdos kryptis išpildo holistinio tobulėjimo sąlygas, nes savo turinyje talpina fizinį, psichinį, socialinį, dvasinį ugdymąsi, siejamą su atitinkamais asmens sveikatos lygmenimis. Tyrimo objektas – asmens holistinė saviugda. Tyrimo tikslas – atskleisti holistinės saviugdos dimensijas asmeniui dalyvaujant NVO sveikos gyvensenos ugdyme.Tyrimo metodai. Duomenų rinkimui taikytas pusiau struktūruotas interviu. Duomenys analizuoti taikant tradicinę kokybinę turinio analizę.Tyrimo rezultatai. Remiantis gautais tyrimo rezultatais parengtas asmens holistinės saviugdos sveikoje gyvensenoje (AHSSG) modelis. Šis modelis atskleidžia NVO sveikos gyvensenos ugdyme dalyvavusių asmenų saviugdos patirtis ir suvokimą, įprasminamus skirtinguose kontekstuose, prielaidose, saviugdos strategijose, įsiterpiančiose būsenose bei rezultatuose. Išvada. Asmens holistinę saviugdą įprasminantis procesas sveikoje gyvensenoje pasireiškia kaip konstruktyvaus ryšio su savimi ir kitais kūrimas, remiantis patirtiniu mokymusi. Asmens holistinės saviugdos sveikoje gyvensenoje rezultatai sietini su asmenybės bei gyvenimo kokybės transformacijomis.
Suaugusių žmonių mitybos įpročių vertinimas remiantis sveikos gyvensenos principais
Authors: Mimgaudytė Lina , Rapolienė Lolita
Published: February 2016

Kiekvieno žmogaus sveikata ir gera savijauta priklauso nuo daugelio dalykų, įskaitant gyvenseną, paveldėjimą, emocinę sveikatą, mitybos įpročius. Tyrimo tikslas - išanalizuoti suaugusių žmonių mitybos įpročius. Metodika. Naudotas vienmomentis kiekybinis tyrimo metodas - apklausa raštu, pritaikius „Healthy Lifestyle Assessment“ klausimyną. Į tyrimą įtraukti 120 abiejų lyčių 18–75 metų atstovai. Statistinei duomenų analizei naudota Microsoft Office programa Excel. Rezultatai. Nustatyta, kad pirmoje vietoje pagal vartojimą yra mėsa ir jos produktai (po 24,1 proc. vyrų ir moterų), pieną ir jo produktus vartoja 15 proc. moterų ir 2,5 proc. vyrų, vaisius ir daržoves - 14 proc. moterų ir 4 proc. vyrų, o grūdinius produktus - 14 proc. moterų ir 1,7 proc. vyrų. Kasdien mėsą valgo vienodai vyrai ir moterys (po 18,3 proc.), šviežias daržoves ir vaisius - 35,8 proc. moterų ir 10 proc. vyrų, pieno produktus- 25 proc. moterų ir 13,3 proc. vyrų, grūdinius produktus - 22,5 proc. moterų ir 7,5 proc. vyrų, saldumynus - 17,5 proc. moterų ir 10 proc. vyrų. Žuvį ir jos produktus dauguma apklaustųjų valgo tik 1 kartą per savaitę (41,7 proc. moterų ir 20 proc. vyrų). Domėjimąsi maisto produktų sudėtimi rodo 60,8 proc. moterų ir 22,5 proc. vyrų, o pagerinti mitybą norėtų pusė moterų ir penktadalis vyrų. 30 - 60 min. laiko 5 - 7 dienas per savaitę vidutiniam fiziniam aktyvumui skiria tik 16,7 proc. moterų ir 14,2 proc. vyrų; 1 kartą per savaitę alkoholį vartoja 7,5 proc. vyrų ir 5,8 proc. moterų); nerūko 51,7 proc. moterų ir tik 13,3 proc. vyrų. Išvados. Didelės dalies Vakarų Lietuvos gyventojų mityba yra nesveika, nereguliari, vartojama per daug mėsos, per mažai valgoma daržovių ir vaisių, grūdinių produktų. Reikia didesnio dėmesio visuomenės švietimui, sveikos gyvensenos ir mitybos ugdymui.
Pacientų išvaizdos ir kūno įvaizdžio problemos: sveikatos priežiūros specialistų patirtis ir kompetencija
Authors: Pačiauskaitė Ineta , Stepukonis Faustas , Jurgutis Arnoldas , Mažuknaitė Ingrida Marija , Norkienė Sigutė
Published: February 2016

Žmogaus kūno išvaizda ir jo įvaizdis visuomenėje yra vienos aktualiausių nūdienos visuomenės sveikatos temų. Darbo tikslas – išanalizuoti sveikatos specialistų patirtį gydant pacientus, turinčius išvaizdos ir kūno įvaizdžio problemų bei jų kompetencijos didinimo poreikius. Kokybiniame tyrime, atliktame grupinės diskusijos metodu, dalyvavo 13 asmenų, kurių didžiąją dalį sudarė tiesiogiai su pacientais, klientais dirbantys sveikatos specialistai – jų buvo 10 (gydytojai, slaugytojai, visuomenės sveikatos specialistai). Duomenų analizei buvo taikomas kokybinės turinio analizės metodas. Analizė buvo atliekama šiais etapais: transkribuotų įrašų skaitymas ir duomenų segmentų išskyrimas, kategorizavimas pagal interviu plano blokus bei duomenų interpretavimas. Analizuojant informantų patirtis dėl darbo su pacientais, turinčiais išvaizdos ir kūno įvaizdžio problemų, nustatyta, jog tiek slaugytojai, tiek gydytojai turi nepakankamai žinių, gebėjimų ir patirties ir laiko konsultuoti pacientus dėl jų išvaizdos ar įvaizdžio. Reikalingos papildomos žinios problemos identifikavimui, gebėjimui tai daryti atskirose amžiaus grupėse. Be to, stokojama psichologinio konsultavimo žinių bei žinių darbui su vaikais dėl jų išvaizdos. Tyrimo dalyvių nuomone, tikslingiausias būtų kompleksinis mokymas apie pacientų, turinčių išvaizdos ir kūno įvaizdžio problemų, gydymą.
Pacientų įsitraukimas kaip inovacijų sveikatos priežiūroje veiksnys
Authors: Vaičekauskaitė Rita , Skirutienė Gitana , Sąlyga Jonas
Published: February 2016

Šiuolaikinėje visuomenėje sveikatos priežiūra patiria didelius ir nuolatinius iššūkius. Jiems įveikti siekiama kurti inovatyvius produktus, kurie suteiktų galimybes taikyti efektyvius gydymo būdus. Tačiau šiuolaikinė sveikatos priežiūros sistema yra labai kompleksinis reiškinys. Todėl pagrindinis iššūkis tenka sveikatos priežiūros sistemos valdymui, kuris užtikrintų šios sistemos integralumą. Šia prasme pacientų įsitraukimas yra tas veiksnys, kuris turi potencialą stiprinti atskirų sveikatos priežiūros sistemos elementų darnų funkcionavimą. Tačiau pacientų įsitraukimui reikia sukurti ir palaikyti tam tikras organizacines struktūras, pavyzdžiui, savitarpio paramos grupes. Inovacijų kontekste svarbu, kad pacientų dalyvavimas būtų ne savitikslis, o kuriantis pridėtinę vertę reiškinys. Todėl yra svarbi atskirų reiškinių sisteminė analizė. Straipsnyje pateikiama teorinė analizė ir empirinis tyrimas.
Pacientų, patyrusių galvos smegenų infarktą, kognityvinių funkcijų įtakos vertinimas ankstyvosios reabilitacijos efektyvumui i ir ii stacionarinės reabilitacijos etapuose: atvejų analizė
Authors: Šostakienė Nijolė , Valeckienė Ina
Published: February 2016

Smegenų infarktas – trečia pagal ligų dažnumą mirtingumo priežastis [12]. Nuo 2002 m. Europos šalyse intraveninė trombolizė patvirtinta kaip smegenų infarkto pirmaeilis gydymo būdas. Trombolizės tikslas yra ištirpinti trombą arba embolą užsikimšusioje galvos smegenų arterijoje ir taip atkurti kraujotaką ir sumažinti galvos smegenų audinio pažeidimą išemijos zonoje per 3 – 4,5 val. nuo išemijos priepuolio pradžios [14]. Taigi, sparčiai tobulėjant galvos smegenų infarkto prevencijai, intervencijai ir postvencijai, vis daugiau dėmesio skiriama ankstyvajai reabilitacijai ūminiu ligos periodu, kurio metu stengiamasi užkirsti kelią negaliai ir tikėtina – mirčiai. Tyrimo tikslas – įvertinti asmenų, patyrusių galvos smegenų infarktą, kognityvinių funkcijų įtaką ankstyvosios reabilitacijos efektyvumui I ir II reabilitacijos etapuose. Tyrimo medžiaga ir metodai. Tyrime dalyvavo 137 respondentai, sergantys galvos smegenų kraujotakos sutrikimu: 58 vyrai ir 79 moterys. Apklaustųjų amžiaus vidurkis 70,23 m. Atvejų analizei buvo pasirinkti du tiriamieji atsitiktine tvarka. Buvo atsižvelgta į jų amžių, lytį, diagnozę, psichologinę emocinę būseną ir kognityvinių funkcijų vertinimą. Tyrimui naudoti retrospektyviniai duomenys. Išvados. Šio tyrimo rezultatai parodė, kad kognityvinių funkcijų sutrikimas tarp lyčių nėra statistiškai reikšmingas (p = 0,370 < 0,05). Po ankstyvosios reabilitacijos taikymo stacionariame I reabilitacijos etape (neurologijos skyriuje) pagerėjo abiejų pacienčių kognityvinės funkcijos. Pacientei, kuriai taikyta trombolizė, kognityvinių funkcijų kokybė pagerėjo per dvigubai trumpesnį laikotarpį I reabilitacijos etape, neurologijos skyriuje. Taip pat kognityvinės funkcijos ir bendra funkcinė būklė gerėjo visos reabilitacijos metu (I ir II reabilitacijos etapuose).
Severe blunt eye trauma causes a decrease in central macular thickness within first 48 hours of trauma
Authors: Atalay Kursat , Kirgiz Ahmet , Kaldirim Havva Erdogan , Mert Metin , Guliyev Derya Alp , Cabuk Kubra Serefoglu , Taskapili Muhittin
Published: February 2016

Background

Blunt eye trauma is an important emergency in ophthalmology practice, and may alter the structure of the macula.

Objectives

To evaluate the optic coherence tomography (OCT) measurements of central macular thickness (CMT) among patients admitted to the hospital within 48 hours of blunt eye trauma.

Methods

Prospective cross-sectional study to evaluate patients who were admitted to hospital with blunt eye trauma within 48 hours trauma. Spectral domain OCT was used to measure macular thickness. CMT measurements of 24 healthy and 26 traumatized eyes of same patients were analyzed as control and case groups, respectively.

Results

The mean CMT measurements were 230.04 ± 18.64 μm in control and 226.50 ± 18.89 μm in traumatized groups. The difference between two groups was not statistically significant (P = 0.412). However, when the patients were classified according to the severity of trauma, CMT measurements of severely injured patients were found significantly lower than both healthy and mildly traumatized eyes (P = 0.008, P = 0.004, respectively).

Conclusions

Early stage macular OCT findings at blunt eye trauma may change with the severity of trauma. We have determined an insignificant increase in the mildly traumatized group in CMT compared with the healthy group within the first 48 hours of blunt trauma as a sign of macular trauma. However, in the severely traumatized group in CMT values significantly decreased, which may be a sign of cellular loss. Further prospective studies with long follow-up periods are warranted to elucidate the effects of this decrease in thickness.
Efectos del programa Usura Cero en el desarrollo económico de MIPYMES en Estelí
Authors: Rodríguez Lanuza Ana Yansis , Herrera Lanzas Ruth Yamalí , Baldelomar Portillo Suyapa Masiel
Published: February 2016

Esta investigación evalúa los efectos del Programa Usura Cero en el desarrollo económico de las MIPYMES creadas por la beneficiadas con el crédito en la ciudad de Estelí en el año 2013 y donde se propondrán estrategias para el fortalecimiento de las mismas. El enfoque de la investigación es cuantitativo. Se aplicaron entrevistas y encuestas para brindar veracidad a la información brindada en el documento.Según la problemática encontrada el programa ha beneficiado en gran cantidad los negocios de las mujeres pues en la actualidad los pequeños negocios se enfrentan con barreras para el acceso a financiamiento en especial cuando no pueden presentar pruebas de ingresos estables; además en la sociedad que vivimos la mujer recibe menos apoyo que el hombre para emprender un negocio también accede más difícilmente al crédito que ofrecen las entidades financieras.Se recomienda la incorporación de libros de ingresos y egresos, atraer nuevos clientes para mejorar su posición en el mercado, utilizar el crédito únicamente para la inversión en el negocio y ampliar su visión empresarial para reducir las debilidades y potenciar las fortalezas y oportunidades, que logren conducir al desarrollo de las MIPYMES.