Local Scale Levels Research Articles

Exploring the effect of low concentration of stannum in lead-free BCT-BZT piezoelectric compositions for energy related applications

Piezoelectric, ferroelectric and electromechanical properties were studied at macroscopic and local scale level in stannum doped (Ba0.88Ca0.12)(SnxZr0.1-xTi0.9)O3 ceramics, with an objective to explore the effect of low content (0 ≤ x ≤ 0.5 at%) of the substituent (Sn) on the functional properties. The results exemplified that the substitution had an influence on the crystal lattice and microstructure that affected the dielectric, ferroelectric, and electromechanical properties. Enhancement in electrical/electromechanical properties were observed with stannum substitution. Optimal electrical properties were obtained in the composition with Sn = 0.3 at% that exhibited maximum piezoelectric constant d33 = 405 pC/N, planar electromechanical coupling factor kp ∼0.41, and saturation polarization Ps=12.1 μC/cm2. The same composition showed an electric-field strain response, Smax ∼0.08% and a converse piezoelectric coefficient, d33* of ∼525 pm/V. Local scale characterization via piezoresponse force microscopy technique revealed complex domain patterns comprising stripe-like macro-domains and featureless nano-sized domains. Energy harvesting and energy storage performance were evaluated for exploring their suitability in energy applications.

Pressure induced phase transitions in Sm-doped BiFeO3 in the morphotropic phase boundary

Sm-doped BiFeO3 compacted powders with composition across the morphotropic phase boundary region were prepared by sol-gel method. Crystal structure, morphology and magnetic state of the compounds were analyzed as a function of dopant concentration, temperature and external pressure using synchrotron and laboratory X-ray diffraction, electron microscopy, Raman and Mössbauer spectroscopy. Application of external pressure shifts the phase transition from the rhombohedral structure to the nonpolar orthorhombic structure towards lower concentration of the dopant content, wherein the amount of the anti-polar orthorhombic phase notably decreases. Raman and Mössbauer spectroscopy data provides additional information about the structural distortion on local scale level which testifies faster formation of nonpolar orthorhombic phase and associated modification in the magnetic state in the compounds subjected to high pressure. Temperature increase leads to the structural transition to the nonpolar orthorhombic phase regardless the structural state at room temperature; furthermore, application of external pressure decreases the phase transition temperature.

Verona Adapt. Modelling as a Planning Instrument: Applying a Climate-Responsive Approach in Verona, Italy

In response to the global challenges brought on by climate change, cities around the world are adapting, innovating through nature-based strategies for sustainable development. Climate adaptation requires new interdisciplinary approaches in which different disciplines as well as research and practice proactively co-create and collaborate on adaptation to reduce the ongoing effects of anthropogenic climate change. Although awareness on climate adaptation is on the rise, new approaches for urban development are still in development. Moreover, existing approaches mainly focus on local-scale levels or lack a crossover with urban and landscape planning. The present contribution offers an example of an integrated approach bridging urban climatology, landscape planning, and governance to assess and develop climate adaptation solutions linking city and district levels. The city of Verona was taken as a case study to test this approach and its implications for the development of a green and blue infrastructure with a climate-responsive master plan for the district of Verona South. Through critical reflection on the application of the approach to the case study, we aimed to identify its potentials and barriers. Based on this reflection, we provide herein recommendations on how climate modelling can be integrated into planning, as well as on how urban planners and urban climatologists can support each other in making credible and salient climate adaptation solutions.

Evolution of the crystal structure and magnetic properties of Sm-doped BiFeO3 ceramics across the phase boundary region

Samarium doped BiFeO3 compounds having nano-size crystallites were prepared by the ethylene glycol assisted sol-gel synthesis method. X-ray diffraction and SEM measurements as well as Raman spectroscopy and FTIR experiments were used to clarify an evolution of the crystal structure on microscopic and local scale levels in the compounds having formula Bi1-xSmxFeO3, where 0 = x ≤ 1. Magnetization measurements along with the structural data were used to determine a correlation between magnetic properties and crystal structure of the compounds. The compounds with 0.1 = x ≤ 0.2 are characterized by the sequence of the structural transitions driven by the dopant increase, viz. from the polar rhombohedral phase to the non-polar orthorhombic phase via two-phase regions characterized by the presence of the anti-polar orthorhombic phase. The concentration regions ascribed to a coexistence of the rhombohedral and the anti-polar orthorhombic phases as well as the anti-polar orthorhombic and the non-polar orthorhombic phases are observed in the ranges 0.12 = x ≤ 0.15 and 0.15 < x < 0.18 respectively. The compounds having single phase rhombohedral structure are characterized by a release of remnant magnetization as compared to ceramics with similar chemical compositions but synthesized by the solid-state reaction method and having microscopic size crystallites. A correlation between the type of structural distortion, morphology of crystallites and an onset of remnant magnetization is discussed highlighting a difference in the evolution of crystal structure and magnetization observed for the Sm-doped ceramics prepared by modified sol-gel method and conventional solid-state reaction technique.

Sensitivity of Grapevine Soil–Water Balance to Rainfall Spatial Variability at Local Scale Level

In rainfed agriculture systems, rainfall water management (harvesting, storage and efficient use) is a key issue. At local scale (i.e. from 100m to 50 km), the impact of rainfall space and time variability on crop water availability is seldom addressed. In order to accurately depict the space and time variations of rainfall at local scale, a dense rain-gauges network composed of 45 rain-gauges has been deployed over 28 km² area, in Burgundy vineyards (North-East France). Rainfall data collected by each rain-gauge from 2014 to 2016 was used as input variables in the grapevine water balance model proposed by Lebon et al. All other climate variables, vineyard and soil parameters were kept strictly identical for each simulation in order to capture the consequences of the sole spatial variability of rainfall on vineyard water status. As rainfall dynamics impact on the vineyard depends on the soil water content, water balance was modelled considering soils with low (50 mm) and medium (150 mm) soil water holding capacities, representative of the soils of the area. The impact of modelled soil water availability for grapevine was assessed using the water deficit stress index (WDSI), i.e. the relative stomatal conductance. Local rainfall variability throughout the vine vegetative period lead to large variations in WDSI: it varied up to 0.3 within the study area solely because of rainfall spatial variability. Using a set of 34 weather stations at mesoscale level over Burgundy (186 km from North to South), we showed that local rainfall might contribute to change in grapevine water status as large as 50% of the simulated regional water balance spatial variability. Our results indicates that local rainfall and its impacts on agricultural production are probably not sufficiently considered in farming systems, potentially leading to in-accurate water management (cover-crop, irrigation) due to sparse rainfall network.

Raman scattering study of the effect of A- and B-site substitution on the room-temperature structure of ABi4Ti4O15

Aurivillius-type materials exhibit promising ferroelectric and multiferroic properties that can be tailored via chemistry variations in the perovskite block. Hence, it is important to clarify the relations composition-structure, also on a local-scale level. The aim of this contribution is to give further insights into the effect of A- and B-site cations to the room-temperature local structure of Aurivillius four-layered ABi4Ti4O15 (A = Sr, Pb, Ba) and Pb1−xBi4+xTi4−xMnxO15 (x = 0, 0.2, 0.4) by Raman scattering. The effect of A-site cation to the local structure of perovskite block was identified by the phonon mode near 750 and 870 cm−1 arising from BO6 stretching. A-site Ba2+, having the largest ionic radius among the considered elements, significantly stiffens the TiO6 octahedra, as derived from the fact that the TiO6 stretching modes have the highest wavenumber for BaBi4Ti4O15, i.e. the Ti-O bond strength is strongest for this compound. The replacement of Ti4+ by Mn3+ cation at the B- site also influences the B-O bond. The comparison of the phonon modes near 700 and 870 cm−1 in Pb1−xBi4+xTi4−xMnxO15 with x = 0, 0.2, and 0.4 shows that the lowest wavenumber, which is due to the elongation of Ti-O bonds is observed for x = 0.4.

Crystal Plasticity Simulations of Haynes 230, an Analysis of Single Crystal and Polycrystalline Experiments

The behavior of a Ni-based superalloy, Haynes 230, was investigated at macro and micro scale level by means of a Crystal Plasticity (CP) model implemented in an open source Finite Element code, Warp3D. Single Crystal and polycrystalline specimens have been experimentally characterized with Digital Image Correlation (DIC) to identify the local strain field evolution. The results of single crystal’s tensile tests were used to obtain an estimation of the constitutive model parameters. Then a polycrystalline model, reproducing a tensile test with loading/unloading steps, was created starting from the microstructural data obtained with EBSD (electron back-scatter diffraction), which allowed the identification of grains geometry and orientations. The polycrystalline simulations were used to verify the prediction of the CP model over the experiment. The results of this study show that the comparison between experiments and numerical analysis is in good agreement on both global and local scale levels.

Mapping Bicycle Crash Risk Patterns on the Local Scale

Currently, mainly aggregated statistics are used for bicycle crash risk calculations. Thus, the understanding of spatial patterns at local scale levels remains vague. Using an agent-based flow model and a bicycle crash database covering 10 continuous years of observation allows us to calculate and map the crash risk on various spatial scales for the city of Salzburg (Austria). In doing so, we directly account for the spatial heterogeneity of crash occurrences. Additionally, we provide a measure for the statistical robustness on the level of single reference units and consider modifiable areal unit problem (MAUP) effects in our analysis. This study is the first of its kind. The results facilitate a better understanding of spatial patterns of bicycle crash rates on the local scale. This is especially important for cities that strive to improve the safety situation for bicyclists in order to address prevailing safety concerns that keep people from using the bicycle as a utilitarian mode of (urban) transport.

Construction of Private Space in An Urban Semioscape: A Case Study in the Sociolinguistics of Globalisation

Abstract Across the world urban semioscapes emerge from multiple and mutually interlocking social activities of the members of sociocultural groups and are established through the deployment of layered configurations of semiotic resources and discourses which index patterns of these activities as well as the underlying norms and values of these groups. A particularly conspicuous semiotic practice which has established itself as a distinct semiotic layer in Slovakia’s urban semioscape is one through which social agents declare certain segments of space as private. By erecting ‘private property’ signs they impose a certain ‘power regime’ on a physical territory but also imprint upon that space a particular ideological meaning. This practice is particularly salient in Slovakia’s geopolitical environment in which the notion of ‘privateness’ was excluded from official ideology under socialism. As language is a principal semiotic mode for the construction of the practice of constructing private space, the practice can also be looked upon as a sociolinguistic phenomenon indexing the post-1989 political and economic transformation processes in Slovakia; that is, the re-establishment of ‘private ownership’ within the larger processes of ‘rectification’ which post-socialist societies underwent in the transformation period. My argument is that the practice is a manifestation of geocultural globalisation on a local scale-level which leads to the emergence of new forms of locality. In the paper I employ Blommaert’s (2010) innovative conceptual toolbox of the sociolinguistics of globalisation’ along with the analytical practices and procedures of geosemiotics and linguistic landscape, and apply them to the corpus of signs which I believe index this practice and establish the topography of private space’ in the urban semioscape examined.

Local-scale diversity and between-year "frozen evolution" of avian influenza A viruses in nature.

Influenza A virus (IAV) in wild bird reservoir hosts is characterized by the perpetuation in a plethora of subtype and genotype constellations. Multiyear monitoring studies carried out during the last two decades worldwide have provided a large body of knowledge regarding the ecology of IAV in wild birds. Nevertheless, other issues of avian IAV evolution have not been fully elucidated, such as the complexity and dynamics of genetic interactions between the co-circulating IAV genomes taking place at a local-scale level or the phenomenon of frozen evolution. We investigated the IAV diversity in a mallard population residing in a single pond in the Czech Republic. Despite the relative small number of samples collected, remarkable heterogeneity was revealed with four different IAV subtype combinations, H6N2, H6N9, H11N2, and H11N9, and six genomic constellations in co-circulation. Moreover, the H6, H11, and N2 segments belonged to two distinguishable sub-lineages. A reconstruction of the pattern of genetic reassortment revealed direct parent-progeny relationships between the H6N2, H11N9 and H6N9 viruses. Interestingly the IAV, with the H6N9 subtype, was re-detected a year later in a genetically unchanged form in the close proximity of the original sampling locality. The almost absolute nucleotide sequence identity of all the respective genomic segments between the two H6N9 viruses indicates frozen evolution as a result of prolonged conservation in the environment. The persistence of the H6N9 IAV in various abiotic and biotic environmental components was also discussed.

Considering effective adaptation options to impacts of climate change for maize production in Ghana

As a contribution to guide policy planning, effective climate change adaptation options to enhance maize production in Ghana were examined. The Agricultural Production Systems Simulator crop model, coupled with statistical downscaled climate scenarios of 9 general circulation models (GCMs) and farmer practices, were used to device adaptation options in the near future (NF) period of 2046–2065 based on IPCC A2 emission scenario at local scale level in Wa and Wenchi agricultural areas of Ghana. Results from the single-maize cropping season at Wa, in the savanna zone indicate that, a 6-week delay in sowing from 1961 to 2000 baseline date of 1st May to 15th June, was the most appropriate way to offset the negative effects of potential climate change resulting in a yield increase of 8.2%. In the forest-savanna transitional zone of Wenchi, a 4-week delay in the major season sowing date from 15th March to 15th April and no change in the minor season sowing date of 15th August resulted in a slight yield increase of 3.9%. On the other hand, a second adaptation option of using a medium heat-tolerant maize variety produced substantial gains in crop yield of 30.1% and 30.5% in savanna and forest-savanna transitional zones respectively with a longer grain-formation period under NF climate change when compared to delaying sowing dates. Effective adaptation options can thus reduce negative impacts of climate change in the NF, but require enabling policy to support its implementation.

Uses and Management Strategies of the Multipurpose Tree Anogeissus leiocarpa in Eastern Burkina Faso

Many people in the semi-arid tropics strongly depend on non-timber forest products (NTFPs) for livelihood. Increasing threats on NTFP-providing tree species, due to land-use intensification and over-harvesting, require ecological studies as well as additional information provided by local people. One important NTFP-providing tree in West Africa is Anogeissus leiocarpa. Even though this species is highly used, ethnobotanical studies on A. leiocarpa are scarce and address mainly qualitative aspects. Our study investigates uses, perceptions of the population development, and management strategies of A. leiocarpa among the Gulimanceba people in eastern Burkina Faso. We conducted a quantitative ethnobotanical survey and investigated distribution of traditional ecological knowledge related to the species on a local scale, i.e. difference in knowledge between villages, genders, and generations. Interviews reveal that A. leiocarpa is harvested by local people for 18 different uses and emphasize its high importance for local people. Ethnobotanical knowledge of A. leiocarpa was mostly evenly spread between genders and generations, while it slightly differed between villages. Although local people did not actively protect A. leiocarpa, current local harvesting modes and management resulted in sustainable use. However, ongoing land-use intensifications require adapted management strategies to guarantee the persistence of this important species. Our results provide, in combination with ecological results of our previous study, appropriate management recommendations. Our study emphasizes the importance of ethnobotanical studies on a local scale level in order to develop management strategies that are reliable in the specific area under the specific circumstances.

Potential impacts of climate change in Germany—Identifying regional priorities for adaptation activities in spatial planning

Spatial planning is considered to be one of the main instruments available to govern adaptation to climate change and climate change impacts in spatial contexts. To meet this challenge spatial planning authorities require information concerning climate change impacts on a regional and local scale level. This paper presents an assessment framework for exploring the impacts of climate change in the context of spatial planning. The framework employs indicators for exposure to climate stimuli and sensitivity to climate change induced impacts. A particular focus was put on producing a comparable classification method with regard to the set of indicators. The application of the framework allows a comprehensive evaluation and comparison of the results for the impacts addressed. The framework was applied at a regional level for the whole of Germany. An indicator based model was developed assessing 11 potential impacts with relevance for the German spatial planning system. Relevant indicators of sensitivity and exposure were compared for a common assessment and spatial analysis of climate change induced potential impacts related to NUTS 3 districts. The impact analysis is applied for three different IPCC greenhouse gas emission scenarios (A2, B1, A1B) and three future periods (2011–2040, 2041–2070, 2071–2100). The assessment provides new information on the spatial distribution of different potential impacts of climate changes in Germany. Regions with cumulative impacts of climate change are identified as hot spot areas which need urgent adaptation activities by spatial planning.

Coupling urban expansion models and hydrological models: How important are spatial patterns?

It is well known that urban expansion has a severe impact on the surface water balance by transforming vegetated covers into sealed surfaces. This transformation causes changing fluxes of evapotranspiration, surface runoff and groundwater recharge. In order to estimate the impact of land cover changes on the surface hydrology, hydrological models are often coupled with different types of land cover change models. It is, however, not clear to what extent spatially-explicit urban expansion scenarios provide an added value in comparison with non-spatial urban expansion models at different scale levels. The objective of this paper is to acquire a better insight in the importance of scale effects involved in the coupling of urban expansion scenarios and hydrological models. The relative importance of using different projections of both (i) quantity and (ii) spatial patterns of urban expansion was analysed at four different scale levels. The highly urbanised Flanders–Brussels region was taken as an example application. Twelve different urban expansion scenarios for 2025 and 2050 were developed and subsequently used as an input in a spatially-distributed water balance model. The results obtained suggest that at the level of the Flanders–Brussels region, an accurate estimation of the quantity of urban expansion should get priority over an accurate projection of the spatial patterns. However, the importance of using accurate projections of the spatial pattern of urban expansion increases systematically at local scale levels. A uniform strategy for coupling urban expansion models and hydrological models thus seems inappropriate. These findings are highly relevant for water management and spatial planning policymakers that typically operate at different administrative levels.

Two-scale approach for the nonlinear dynamic analysis of RC structures with local non-prismatic parts

There is general agreement in the fact that fully three-dimensional (3D) numerical techniques provide the most precise tools for simulating the behavior of RC buildings even when their computational costs for real structures became them unpractical. Moreover, one-dimensional formulations (1D) are rather limited for predicting the mechanical behavior of framed structures which present local weakness that can determine their global responses, such as it is the case of poor detailed joints of RC buildings in seismic zones or precast concrete structures. An alternative approach, combining both simplicity and computational efficiency, is given by coupling reduced models for prismatic elements with full 3D models for the zones corresponding to connecting joints. In this work, a two-scale approach is developed for obtaining the nonlinear dynamic response of RC buildings with local non-prismatic parts. At global scale level all the elements are rods; however, if local parts with complex geometry appear, the corresponding elements are analyzed considering fully 3D models which constitute the local scale level. The dimensional-coupling between scales is performed imposing the kinematics hypothesis of the beam model on surface-interfaces of the 3D model. An iterative Newton–Raphson scheme which considers the interaction between scales is developed to obtain the response at global level. The tangential stiffness of the local models are obtained numerically. Computationally, the problem is managed by means of a master–slave approach, where the global scale problem acts as the master and the local models are the slaves; iterative communication between scales considers internal forces and moments as well as tangential tensors. The process stops when global convergence is achieved. From the computational point of view, the developed method is implemented in a parallelized scheme, where the master and slave problems are solved independently by different programs thus minimizing the intervention on existing codes specific for beams and solids. Finally, numerical examples are included.

Dilatational and distortional behavior of cracks in magnetoelectroelastic materials

Dilatation and distortion are the two basic modes of deformation in continuum mechanics. They occur at different time and position depending on the size scale under consideration. At the macroscopic scale, dilatational waves are said to arrive prior to distortional waves at a given location. Macro-plastic deformation caused by distortion off to the side of a macro-crack precedes that of macro-fracture caused by dilatation ahead of a macro-crack. Micro-plasticity and micro-cracking can introduce non-linearity to the macroscopic material behavior. Such effects can be modeled directly as geometric defects (dislocations and/or micro-cracks) or indirectly by introducing effective material coefficients in the constitutive relations. Material anisotropy and/or inhomogeneity, however, do not separate hydrostatic tension (or compression) state of stress from that of shear on the octahedral planes. The latter is the basis of the von-Mises yield criterion. Stated in terms of the strain energy density function, linear separation into one part for dilatation and another for distortion can be made only if the material is linearly isotropic and homogeneous. Recent trends of miniaturization of electronic components requires a better knowledge of how the micro-structure would affect the material response due to mechanical stress as well as other sources of disturbances. Continuum mechanics results need to be interpreted over a wider range of time and size scales, and a better understanding of their limitations need to be achieved. In what follows, the stationary values of the strain energy density function d W/d V will be shown to yield an interpretation of the local dilatational and distortional behavior of anisotropic (or non-homogeneous) materials with or without cracks. This quantity is not only attractive from the view point of mathematics and mechanics because it is positive definite, it also makes physical sense for non-linear materials where the quotient d W/d V could still be used to separate dilatation from distortion. Application of the minimum local energy density function should be distinguished from the global energy minimization method used in molecular dynamics which is applied to determine the equilibrium configuration of atoms. The response of a line crack in a magnetoelectroelastic (MEE) material will be used for discussion in order to illustrate the character of multi-scaling. Expressed differently is that the time and size scales for the transfer of magnetic, electric and elastic energies may not be the same. An arbitrary limiting process that assumes vanishing crack segments created by all forms of energy may not be justified at the local scale levels. What has been assumed at the global scale for isotropic and homogeneous situations may not be valid at the local scale levels where anisotropy and non-homogeneity are the rule rather then the exception. Numerical results are obtained for the composite BaTiO 3–CoFe 2O 4. They show how magnetic and electric poling normal to a line crack could greatly affect the interplay between volume change and shape change of the local continuum elements at both the macroscopic and microscopic scale level. The micro-energy-density function is found to be three orders of magnitude higher than that at the macroscopic scale. The volume fraction of the inclusions made of BaTiO 3 also comes into play for both Mode I and II mechanical loading. Potential micro-crack bifurcation is predicted in a region very close to the crack tip while macro-crack initiation occurs in a straight line for the MEE material. The information is relevant for developing macro- and micro-crack models where quantities and situations of secondary importance can be weeded out.

Planning for Biodiversity: Issues and Examples

Review: Planning for Biodiversity: Issues and Examples By Sheila Peck Reviewed by Elery Hamilton-Smith University of Wageningen, Netherlands Peck, Sheila. Planning for Biodiversity: Issues and Examples. Washington, DC: Island Press, 1998. 221 pp. ISBN 1-55963-401-4 (paper). US$27.50 This is an eminently readable book on a very important topic. It outlines a number of basic principles in providing for biodiversity within the context of urban and regional planning. The various case studies bring the subject to life, and in themselves give a positive vision to the maintenance of eco- systems. It focuses on the local-scale level of action that commonly falls within the province of the planning profession and this is both a valuable and practical focus. But on the broader scale, it is disappointing in that it devotes little attention to the role of protected areas, although its focus on off- reserve conservation is indeed welcome. Regrettably, particularly for U.S. readers, it draws entirely upon experience in the United States. There is virtually no reference at all to broad-scale national or even state frameworks equivalent to the landcare and similar movements now found in many countries. It deals with seven topics: the conceptual nature of biodiversity, developing priorities in conservation, understanding change and disturbance, spatial issues, design of reserves, collecting baseline data, and monitoring for adaptive management. Unfortunately, there are some serious omissions. While dealing with how planning and management techniques might be used to maintain biodiversity, there is no baseline discussion on why biodiversity is important—the very spring of criteria for selecting between various options for action. Perhaps as a consequence, the only criteria for establishing conservation priority are those concerned with the scale of the conservation project— very important to planning, but only one part of a complex picture. The rising interest in risk assessment and risk management strategies is not addressed, nor is the ubiquitous problem of conflicting stakeholder objectives. Similarly, the discussion of the impacts of change and disturbance and the review of methods for resource inventory and monitoring are both relatively superficial and only briefly describe biological assessment. There is no assessment of the buzzword of sustainability and the application of that concept. Finally, it is disappointing to find little on the principles of

A Computer System for Simulating the Transfer of Pollutants over Complex Terrain - Some Recent Applications

The EURIDICE code system, jointly developed by the CEA-France and DEMOKRITOS-Greece, is an ensemble of codes designed to perform wind field calculations and atmospheric dispersion analysis at meso and/or local scale level, over terrain of great complexity and under realistic meteorological conditions. The implemented concept of partially active (i.e. containing air/ground contact surfaces) user-defined computational cells with high terrain resolution permits the performance of efficient and reliable boundary layer analysis using reasonable computation resources. Eulerian, puff, and Monte Carlo dispersion models are incorporated into the system. Some of the recent applications of the Euridice code system are presented here, including simulations of the ASCOT Rocky Flats experiments and dispersion in the Greater Athens area.