Enhancing the effectiveness of policy-relevant integrative research in rural areas

There has been much debate about the importance of policy-relevant research in geography over the last decade. There has also been an increasing recognition by policymakers of the importance of integrative (interdisciplinary and transdisciplinary) approaches to policy-relevant research. However, geographers have been more reluctant than their colleagues in other social and natural sciences to embrace integrative research collaborations. For integrative research to achieve its full potential and to encourage greater participation from the geographical research community, we need to increase our understanding of its potential value, but also some of the challenges that it poses, and how these can be overcome. In this paper, we consider the processes involved in conducting successful integrative research from the perspective of researchers involved in these projects. We base our analysis on the results of a questionnaire survey of international integrative research programmes on environmental issues in rural areas, combined with our own experiences of working in integrative research. We conclude that effective integrative research depends on the establishment of a clear conceptual framework, the use of appropriate temporal and spatial scales in the research, effective language and communication, time and commitment, and trust and respect. We also highlight the value of stakeholder involvement in integrative research to ensure the policy relevance of the work and provide a mechanism to assist with effective knowledge transfer of the results.     

Characteristics of intense rainfall over Gujarat State (India) based on percentile criteria

The study focuses on the spatial and temporal variations of intense/extreme rainfall events over Gujarat State (India) during the period 1970–2014. Average monsoon rainfall for the state shows a significant increasing trend, with an increase of 48 mm/decade. Some of the stations in the Saurashtra region show a statistically significant increasing trend but none of the stations in the state show a decreasing trend. The increasing trend in monsoon rainfall is very significant for the past three decades, with an increase of 167 mm/decade. Instead of fixed absolute threshold values, relative threshold values of rainfall corresponding to the 95th, 98th, 99th and 99.5th percentiles for each station have been proposed to represent heavy, very heavy, intense and extreme rainfall, which varied between 70–120, 105–160, 130–210 and 165–280 mm, respectively. Significant increasing trends are observed for the frequency of heavy and very heavy rainfall events over the state.     

Sandy beach ecosystems: key features, sampling issues, management challenges and climate change impacts

Escalating pressures caused by the combined effects of population growth, demographic shifts, economic development and global climate change pose unprecedented threats to sandy beach ecosystems worldwide. Conservation of beaches as functional ecosystems and protection of their unique biodiversity requires management interventions that not only mitigate threats to physical properties of sandy shores, but also include ecological dimensions. Yet, beach management remains overwhelmingly focused on engineering interventions. Here we summarise the key outcomes of several workshops, held during the 2006 Sandy Beach Ecology Symposium in Vigo, Spain, that addressed issues of climate change, beach management and sampling methodology. Because efficient communication between managers and ecologists is critical, we summarise the salient features of sandy beaches as functional ecosystems in 50 'key statements'; these provide a succinct synopsis of the main structural and functional characteristics of these highly dynamic systems. Key outcomes of the workshops include a set of recommendations on designs and methods for sampling the benthic infaunal communities of beaches, the identification of the main ecological effects caused by direct and indirect human interventions, the predicted consequence of climate change for beach ecosystems, and priority areas for future research.     

Fourier amplitude sensitivity test applied to dynamic combined finite-discrete element methods–based simulations

Fracture propagation plays a key role for a number of applications of interest to the scientific community, from dynamic fracture processes like spallation and fragmentation in metals to failure of ceramics, airplane wings, etc. Simulations of material deformation and fracture propagation rely on accurate knowledge of material characteristics such as material strength and the amount of energy being dissipated during the fracture process. Within the combined finite-discrete element method (FDEM) framework material fracture behavior is typically described through a parametrized softening curve, which defines a stress-strain relationship unique to each material. We apply the Fourier amplitude sensitivity test to explore how each of these parameters influences the simulated damage processes and to determine the key input parameters that have the most impact on the model response. We present several sensitivity numerical experiments for the simulation of a split Hopkinson pressure bar (SHPB) test for weathered granite samples using different combinations of model parameters. We validate the obtained results against SHPB experimental data. The experiments show that the model is mostly sensitive to parameters related to tensile and shear strengths, even in the presence of other parameter perturbations. The results suggest that the specification of tensile and shear strengths at the interfaces dominate the stress-time history of the FDEM simulation of SHPB test.     

Diverse forms of primordial organic matter identified in interplanetary dust particles

Abstract– Coordinated in situ transmission electron microscopy and isotopic measurements of carbonaceous phases in interplanetary dust particles were performed to determine their origins. Five different types of carbonaceous materials were identified based on their morphology and texture, observed by transmission electron microscopy: globular, vesicular, dirty, spongy, and smooth. Flash heating experiments were performed to explore whether some of these morphologies are the result of atmospheric entry processes. Each of these morphologies was found to have isotopically anomalous H and N. Rare C isotopic anomalies were also observed. The isotopic and morphological properties of several of these phases, particularly the organic globules, are remarkably similar to those observed in other extraterrestrial materials including carbonaceous chondrites, comet 81P/Wild 2 particles collected by the Stardust spacecraft, and Antarctic micrometeorites, indicating that they were widespread in the early solar system. The ubiquitous nature and the isotopic anomalies of the nanoglobules and some other morphologies strongly suggest that these are very primitive phases. Given that some of the isotopic anomalies (D and ¹⁵N excesses) are indicative of mass fractionation chemical reactions in a very cold environment, and some others (¹³C and ¹⁵N depletions) have other origins, these carbonaceous phases come from different reservoirs. Whatever their origins, these materials probably reflect the first stages of the evolution of solar system organic matter, having originated in the outermost regions of the protosolar disk and/or interstellar cold molecular clouds.     

Understanding the evolution of a disaster��a Framework for Assessing Crisis in a System Environment (FACSE)

To understand the evolution of a disaster, we propose a Framework for Assessing Crisis in a System Environment (FACSE). FACSE is set in a multi-system environment, containing the human system as well as the various natural and technological systems that interact with people. We take a lifecycle perspective, via which we quantify rhythms of life exhibited in multiple systems, across different scales, at different times. The lifecycle perspective also implies a relative approach in that rhythms of life during time t can be compared against those during t-1. We illustrate how rhythms of life in the human system can be measured at different scales. We propose a new concept??the degree of disaster, which is a composite score that encompasses the various measurements of rhythms of life from multiple systems, across different scales. We conclude the paper by discussing the potential offered by FACSE in disaster research as well as the limitations.     

A modeling approach for assessing the effect of multiple alpine lakes in sequence on nutrient transport

The effects of a single lake on downstream water chemistry may be compounded by the presence of additional lakes within the watershed, augmenting or negating the effects of the first lake. Multiple, linked lakes are a common feature of many watersheds and these resemble reactors in series often studied in engineering. The effects of multiple lakes in series on nutrient transport are largely unexplored. We populated and calibrated a simple lake model to investigate the role of a sub-alpine lake (Bull Trout Lake (BTL), Rocky Mountains, USA) on the transport of the macronutrients during the summer of 2008. Further, we developed a sequential model in which four identical lakes (copies of the BTL model) were connected in series. All lakes in the sequence retarded the flux of nutrients, thus slowing their transport downstream. The first lake in the sequence dramatically altered stream water chemistry and served as a sink for C and P and a source of N, while additional lakes downstream became sources of C, N and P. Although additional downstream lakes resulted in important changes to water chemistry and nutrient transport, the nature of the changes were similar from Lakes 2 to 4 and the magnitude of the changes diminished with distance downstream. Our lake model served as an effective tool for assessing the nutrient budget of the lake and the hypothetical effect of multiple lakes in sequence in a landscape limnology framework.     

Coupling of solid deformation and pore pressure for undrained deformation—a discrete element method approach

This paper presents a numerical scheme for fluid‐particle coupling that uses the discrete element method by taking into consideration solid deformation and pore pressure generation. A new water particle element is introduced to calculate pore water pressure due to porosity changes. The water particle element has the same size and shape as the solid element and experiences the same amount of deformation. On the basis of the effective stress principle at the element contact, the total force is equal to the sum of the force transmitted through the solid element contact and the water particle force due to pore water pressure. Analytical solutions of traditional soil mechanics problems, such as isotropic compression and consolidated triaxial undrained test, are used to quantitatively validate the proposed model. The numerical results show good agreement between the model and the analytical solutions. The model therefore provides an effective method to calculate pore pressure in a porous medium in discrete modeling.     

Frictional contact algorithms in SPH for the simulation of soil–structure interaction

Simulation of frictional contact between soils and rigid or deformable structure in the framework of smoothed particle hydrodynamics (SPH) is presented in this study. Two algorithms are implemented into the SPH code to describe contact behavior, where the contact forces are calculated using the law of conservation of momentum based on ideal plastic collision or using the criteria of partial penetrating. In both algorithms, the problem of boundary deficiency inherited from SPH is properly handled so that the particles located at contact boundary can have precise acceleration, which is critical for contact detection. And the movement and rotation of the rigid structure are taken into account so that it is easy to simulate the process of pile driving or movement of a retaining wall in geotechnical engineering analysis. Furthermore, the capability of modeling deformability of a structure during frictional contact simulations broadens the fields of SPH application. In contrast to previous work dealing with contact in SPH, which usually use particle‐to‐particle contact or ignoring sliding between particles and solid structure, the method proposed here is more efficient and accurate, and it is suitable to simulate interaction between soft materials and rigid or deformable structures, which are very common in geotechnical engineering. A number of numerical tests are carried out to verify the accuracy and stability of the proposed algorithms, and their results are compared with analytical solutions or results from finite element method analysis. Good agreement obtained from these comparisons suggests that the proposed algorithms are robust and can be applied to extend the capability of SPH in solving geotechnical problems. Copyright © 2013 John Wiley & Sons, Ltd.