scholarly journals Opportunities from low-resolution modelling of river morphology in remote parts of the world

2013 ◽  
Vol 1 (1) ◽  
pp. 407-435
Author(s):  
M. Nones ◽  
M. Guerrero
Keyword(s):  
Cross Sections ◽  
Large Scale ◽  
Initial Conditions ◽  
Large Rivers ◽  
Small Scale ◽  
First Case ◽  
The World ◽  
High Level ◽  
D Model

Abstract. The study of rivers morphodynamics requires modelling of a variety of processes ranging from the typical small scale of fluid mechanics (e.g. flow turbulence dissipation) to the large scale of landscape evolution (e.g. fan deposition). However, simplifications inherent in the long-term modelling of large rivers derive from limited computational resource and the high level of processes detail (i.e. spatial and temporal resolution). These modelling results depend on processes parameterization and calibration over detailed field data (e.g. initial morphology). Thus, in these cases, simplified tools are attractive. Here, a simplified 1-D code is used for the modelling of very large rivers. A synthetic description of the variation of cross-sections shape is implemented on the basis of satellite images, typically available also in remote parts of the world. The model's flexibility is highlighted here, by presenting two applications. In the first case the model is used for analysing the long-term evolution of the Lower Zambezi (Africa) related to the construction of two reservoirs for hydropower exploitation; while, in the second case, the same code is applied for studying the evolution of the Middle and Lower Parana (Argentina) in light of climate variability. In both cases, having only basic data for boundary and initial conditions, the 1-D model provides results that are in agreement with past studies and that may be used to assist sediment management at watershed scale or at boundaries of more detailed modelling.

scholarly journals Opportunities from low-resolution modelling of river morphology in remote parts of the world

2014 ◽  
Vol 2 (1) ◽  
pp. 9-19 ◽  
Author(s):  
M. Nones ◽  
M. Guerrero ◽  
P. Ronco
Keyword(s):  
Cross Sections ◽  
Large Scale ◽  
Initial Conditions ◽  
Large Rivers ◽  
Small Scale ◽  
First Case ◽  
The World ◽  
High Level ◽  
Computational Resources

Abstract. River morphodynamics are the result of a variety of processes, ranging from the typical small-scale of fluid mechanics (e.g. flow turbulence dissipation) to the large-scale of landscape evolution (e.g. fan deposition). However, problems inherent in the long-term modelling of large rivers derive from limited computational resources and the high level of process detail (i.e. spatial and temporal resolution). These modelling results depend on processes parameterization and calibrations based on detailed field data (e.g. initial morphology). Thus, for these cases, simplified tools are attractive. In this paper, a simplified 1-D approach is presented that is suited for modelling very large rivers. A synthetic description of the variations of cross-sections shapes is implemented on the basis of satellite images, typically also available for remote parts of the world. The model's flexibility is highlighted here by presenting two applications. In the first case, the model is used for analysing the long-term evolution of the lower Zambezi River (Africa) as it relates to the construction of two reservoirs for hydropower exploitation. In the second case, the same model is applied to study the evolution of the middle and lower Paraná River (Argentina), particularly in the context of climate variability. In both cases, having only basic data for boundary and initial conditions, the 1-D model provides results that are in agreement with past studies and therefore shows potential to be used to assist sediment management at the watershed scale or at boundaries of more detailed models.

Species Responses to Grazing and Environmental-Factors in an Arid Halophytic Shrubland Community

1987 ◽  
Vol 35 (2) ◽  
pp. 135 ◽  
Author(s):  
RB Hacker
Keyword(s):  
Environmental Factors ◽  
Soil Salinity ◽  
Large Scale ◽  
Chemical Properties ◽  
Grazing Pressure ◽  
Aerial Photographs ◽  
Small Scale ◽  
Factors Affecting ◽  
Species Responses

Species responses to grazing and environmental factors were studied in an arid halophytic shrubland community in Western Australia. The grazing responses of major shrub species were defined by using reciprocal averaging ordination of botanical data, interpreted in conjunction with a similar ordination of soil chemical properties and measures of soil erosion derived from large-scale aerial photographs. An apparent small-scale interaction between grazing and soil salinity was also defined. Long-term grazing pressure is apparently reduced on localised areas of high salinity. Environmental factors affecting species distribution are complex and appear to include soil salinity, soil cationic balance, geomorphological variation and the influence of cryptogamic crusts on seedling establishment.

Het Hoge Kempen ruraal-industrieel transitielandschap

2019 ◽  
Vol 4 (3) ◽  
pp. 194-207
Author(s):  
PIET GELEYNS
Keyword(s):  
Large Scale ◽  
Western Europe ◽  
Farming System ◽  
Small Scale ◽  
Coal Miners ◽  
Garden Cities ◽  
World Heritage List ◽  
The World ◽  
Outstanding Universal Value ◽  
Extensive Farming

The Hoge Kempen rural industrial transition landscape: a layered landscape of Outstanding Universal Value? Up until the beginning of the 20th century, the eastern part of the Belgian province of Limburg was a sparsely populated and not very productive part of the country. The dominating heathland was maintained with sheep, which were an essential part of a small-scale extensive farming system. This all changed when coal was discovered in 1901. Seven large coalmines were established in a few decades, each one employing thousands of coal-miners. This also meant that entire new garden cities were built, to house the coal-miners and their families. The confrontation between the small-scale traditional land-use and the new large-scale industrial developments defines the landscape up to today. The scale and the force of the turnover are considered unprecedented for Western Europe, which is why it is being presented by Belgium for inclusion in the World Heritage List.

1-D Model Analysis of Tesla Turbine for Small Scale Organic Rankine Cycle (ORC) System

2017 ◽  
Author(s):  
Jian Song ◽  
Chun-wei Gu
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Organic Rankine Cycle ◽  
Axial Flow ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Working Fluid ◽  
Small Scale ◽  
Low Grade ◽  
D Model

Energy shortage and environmental deterioration are two crucial issues that the developing world has to face. In order to solve these problems, conversion of low grade energy is attracting broad attention. Among all of the existing technologies, Organic Rankine Cycle (ORC) has been proven to be one of the most effective methods for the utilization of low grade heat sources. Turbine is a key component in ORC system and it plays an important role in system performance. Traditional turbine expanders, the axial flow turbine and the radial inflow turbine are typically selected in large scale ORC systems. However, in small and micro scale systems, traditional turbine expanders are not suitable due to large flow loss and high rotation speed. In this case, Tesla turbine allows a low-cost and reliable design for the organic expander that could be an attractive option for small scale ORC systems. A 1-D model of Tesla turbine is presented in this paper, which mainly focuses on the flow characteristics and the momentum transfer. This study improves the 1-D model, taking the nozzle limit expansion ratio into consideration, which is related to the installation angle of the nozzle and the specific heat ratio of the working fluid. The improved model is used to analyze Tesla turbine performance and predict turbine efficiency. Thermodynamic analysis is conducted for a small scale ORC system. The simulation results reveal that the ORC system can generate a considerable net power output. Therefore, Tesla turbine can be regarded as a potential choice to be applied in small scale ORC systems.

scholarly journals Design of Compliant Joints for Large Scale Structures

2020 ◽  
Author(s):  
Angela Nastevska ◽  
Jovana Jovanova ◽  
Mary Frecker
Keyword(s):  
Large Scale ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Small Scale ◽  
Nonlinear Bending ◽  
Large Scale Structures ◽  
Compliant Joints ◽  
Scale Structures ◽  
High Level ◽  
Novel Design

Abstract Large scale structures can benefit from the design of compliant joints that can provide flexibility and adaptability. A high level of deformation is achieved locally with the design of flexures in compliant mechanisms. Additionally, by introducing contact-aided compliant mechanisms, nonlinear bending stiffness is achieved to make the joints flexible in one direction and stiff in the opposite one. All these concepts have been explored in small scale engineering design, but they have not been applied to large scale structures. In this paper the design of a large scale compliant mechanism is proposed for novel design of a foldable shipping container. The superelasticity of nickel titanium is shown to be beneficial in designing the joints of the compliant mechanism.

scholarly journals Topophilia, Placemaking, and Boundary Work

2022 ◽  
Vol 6 (GROUP) ◽  
pp. 1-33
Author(s):  
Janghee Cho ◽  
Samuel Beck ◽  
Stephen Voida
Keyword(s):  
Large Scale ◽  
Methodological Approach ◽  
Work Practice ◽  
Small Scale ◽  
Work From Home ◽  
Humanistic Geography ◽  
Working From Home ◽  
Long Term Impact

The COVID-19 pandemic fundamentally changed the nature of work by shifting most in-person work to a predominantly remote modality as a way to limit the spread of the coronavirus. In the process, the shift to working-from-home rapidly forced the large-scale adoption of groupware technologies. Although prior empirical research examined the experience of working-from-home within small-scale groups and for targeted kinds of work, the pandemic provides HCI and CSCW researchers with an unprecedented opportunity to understand the psycho-social impacts of a universally mandated work-from-home experience rather than an autonomously chosen one. Drawing on boundary theory and a methodological approach grounded in humanistic geography, we conducted a qualitative analysis of Reddit data drawn from two work-from-home-related subreddits between March 2020 and January 2021. In this paper, we present a characterization of the challenges and solutions discussed within these online communities for adapting work to a hybrid or fully remote modality, managing reconfigured work-life boundaries, and reconstructing the home's sense of place to serve multiple, sometimes conflicting roles. We discuss how these findings suggest an emergent interplay among adapted work practice, reimagined physical (and virtual) spaces, and the establishment and continual re-negotiation of boundaries as a means for anticipating the long-term impact of COVID on future conceptualizations of productivity and work.

scholarly journals Low-cost Large Scale Vermicompost Unit

2021 ◽  
Vol 2115 (1) ◽  
pp. 012026
Author(s):  
Sonam Solanki ◽  
Gunendra Mahore
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Small Scale ◽  
Scale Production ◽  
Key Innovation ◽  
Main Challenge ◽  
Long Run ◽  
Large Scale Production ◽  
Term Maintenance

Abstract In the current process of producing vermicompost on a large-scale, the main challenge is to keep the worms alive. This is achieved by maintaining temperature and moisture in their living medium. It is a difficult task to maintain these parameters throughout the process. Currently, this is achieved by building infrastructure but this method requires a large initial investment and long-run maintenance. Also, these methods are limited to small-scale production. For large-scale production, a unit is developed which utilises natural airflow with water and automation. The main aim of this unit is to provide favourable conditions to worms in large-scale production with very low investment and minimum maintenance in long term. The key innovation of this research is that the technology used in the unit should be practical and easy to adopt by small farmers. For long-term maintenance of the technology lesser number of parts are used.

scholarly journals Cambridge Servicemen’s Memorial (Breuer, 1945): espacio público para el recuerdo

2019 ◽  
Vol 6 (2) ◽  
pp. 27
Author(s):  
Salvador José Sanchís Gisbert ◽  
Pedro Ponce Gregorio ◽  
Ignacio Peris Blat
Keyword(s):  
Public Space ◽  
Large Scale ◽  
Residential Buildings ◽  
Small Scale ◽  
First Year ◽  
Residential Land ◽  
The Public ◽  
International Recognition ◽  
The World ◽  
Strong Commitment

Marcel Breuer was in the first year of architectural technicians to graduate from Bauhaus School. The peculiar education he received there allowed him to explore the concept of design in its broadest sense. In his European stage we find, on the most private and small scale, unique solutions for furniture. In his first American stage we see a strong commitment with solutions related to the residential land and, when he earned international recognition, he developed large scale solutions for his public non-residential buildings and urban equipments in locations all over the world. It is strange to see that an architect like him did not have the opportunity to materialize any of his proposals associated with the public space. The 1945 Cambridge Servicemen’s Memorial project, also known as the Memorial War, is the most significant one he developed in his last years in Cambridge. Had it been built, it would have been a valuable example of modernity and contemporary reinterpretation of the monument in the public space.

scholarly journals Nitrification of the lowermost stratosphere during the exceptionally cold Arctic winter 2015–2016

2019 ◽  
Vol 19 (21) ◽  
pp. 13681-13699 ◽  
Author(s):  
Marleen Braun ◽  
Jens-Uwe Grooß ◽  
Wolfgang Woiwode ◽  
Sören Johansson ◽  
Michael Höpfner ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Cross Sections ◽  
Large Scale ◽  
Potential Temperature ◽  
Lagrangian Model ◽  
The Arctic ◽  
Small Scale ◽  
Mixing Ratios ◽  
Fine Structures ◽  
The Impact

Abstract. The Arctic winter 2015–2016 was characterized by exceptionally low stratospheric temperatures, favouring the formation of polar stratospheric clouds (PSCs) from mid-December until the end of February down to low stratospheric altitudes. Observations by GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) on HALO (High Altitude and LOng range research aircraft) during the PGS (POLSTRACC–GW-LCYCLE II–SALSA) campaign from December 2015 to March 2016 allow the investigation of the influence of denitrification on the lowermost stratosphere (LMS) with a high spatial resolution. Two-dimensional vertical cross sections of nitric acid (HNO3) along the flight track and tracer–tracer correlations derived from the GLORIA observations document detailed pictures of wide-spread nitrification of the Arctic LMS during the course of an entire winter. GLORIA observations show large-scale structures and local fine structures with enhanced absolute HNO3 volume mixing ratios reaching up to 11 ppbv at altitudes of 13 km in January and nitrified filaments persisting until the middle of March. Narrow coherent structures tilted with altitude of enhanced HNO3, observed in mid-January, are interpreted as regions recently nitrified by sublimating HNO3-containing particles. Overall, extensive nitrification of the LMS between 5.0 and 7.0 ppbv at potential temperature levels between 350 and 380 K is estimated. The GLORIA observations are compared with CLaMS (Chemical Lagrangian Model of the Stratosphere) simulations. The fundamental structures observed by GLORIA are well reproduced, but differences in the fine structures are diagnosed. Further, CLaMS predominantly underestimates the spatial extent of HNO3 maxima derived from the GLORIA observations as well as the overall nitrification of the LMS. Sensitivity simulations with CLaMS including (i) enhanced sedimentation rates in case of ice supersaturation (to resemble ice nucleation on nitric acid trihydrate (NAT)), (ii) a global temperature offset, (iii) modified growth rates (to resemble aspherical particles with larger surfaces) and (iv) temperature fluctuations (to resemble the impact of small-scale mountain waves) slightly improved the agreement with the GLORIA observations of individual flights. However, no parameter could be isolated which resulted in a general improvement for all flights. Still, the sensitivity simulations suggest that details of particle microphysics play a significant role for simulated LMS nitrification in January, while air subsidence, transport and mixing become increasingly important for the simulated HNO3 distributions towards the end of the winter.

scholarly journals Finite Symmetries in Agent-Based Epidemic Models

2019 ◽  
Vol 24 (2) ◽  
pp. 44 ◽  
Author(s):  
Gilberto M. Nakamura ◽  
Ana Carolina P. Monteiro ◽  
George C. Cardoso ◽  
Alexandre S. Martinez
Keyword(s):  
Population Size ◽  
Transition Matrix ◽  
Large Scale ◽  
Initial Conditions ◽  
Disease Outbreaks ◽  
Epidemic Models ◽  
Small Scale ◽  
Stochastic Effects ◽  
Agent Based ◽  
Computational Performance

Predictive analysis of epidemics often depends on the initial conditions of the outbreak, the structure of the afflicted population, and population size. However, disease outbreaks are subjected to fluctuations that may shape the spreading process. Agent-based epidemic models mitigate the issue by using a transition matrix which replicates stochastic effects observed in real epidemics. They have met considerable numerical success to simulate small scale epidemics. The problem grows exponentially with population size, reducing the usability of agent-based models for large scale epidemics. Here, we present an algorithm that explores permutation symmetries to enhance the computational performance of agent-based epidemic models. Our findings bound the stochastic process to a single eigenvalue sector, scaling down the dimension of the transition matrix to o ( N 2 ) .

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