scholarly journals A highly flexible laboratory setup to demonstrate granular flow characteristics

2020 ◽  
Vol 104 (2) ◽  
pp. 1581-1596
Author(s):  
Thomas Heinze
Keyword(s):  
Granular Flow ◽  
Large Scale ◽  
Numerical Models ◽  
Low Cost ◽  
Experimental Investigations ◽  
Small Scale ◽  
Local Pressure ◽  
Slope Length ◽  
Runout Distance ◽  
Laboratory Setup

Abstract Dynamics of snow avalanches or landslides can be described by rapid granular flow. Experimental investigations of granular flow at laboratory scale are often required to analyze flow behaviour and to develop adequate mathematical and numerical models. Most investigations use image-based analysis, and additional sensors such as pressure gauges are not always possible. Testing various scenarios and parameter variations such as different obstacle shapes and positions as well as basal topography and friction usually requires either the construction of a new laboratory setups for each test or a cumbersome reconstruction. In this work, a highly flexible and modular laboratory setup is presented based on LEGO bricks. The flexibility of the model is demonstrated, and possible extensions for future laboratory tests are outlined. The setup is able to reproduce published laboratory experiments addressing current scientific research topics, such as overflow of a rigid reflector, flow on a bumpy surface and against a rigid wall using standard image-based analysis. This makes the setup applicable for quick scenario testing, e.g. for hypothesis testing or for low-cost testing prior to large-scale experiments, and it can contribute to the validation of external results and to benchmarks of numerical models. Small-scale laboratory setups are also very useful for demonstration purposes such as education and public outreach, both crucial in the context of natural hazards. The presented setup enables variation of parameters such as of slope length, channel width, height and shape, inclination, bed friction, obstacle position and shape, as well as density, composition, amount and grain size of flowing mass. Observable quantities are flow type, flow height, flow path and flow velocity, as well as runout distance, size and shape of the deposited material. Additional sensors allow further quantitative assessments, such as local pressure values.

Coupled Thermo-Hydro-Geochemical Models of Engineered Barrier Systems: The Febex Project

2000 ◽  
Vol 663 ◽  
Author(s):  
J. Samper ◽  
R. Juncosa ◽  
V. Navarro ◽  
J. Delgado ◽  
L. Montenegro ◽  
...  
Keyword(s):  
Large Scale ◽  
Reference Model ◽  
Numerical Models ◽  
Full Scale ◽  
Small Scale ◽  
Model Parameters ◽  
In Situ Test ◽  
Wide Range ◽  
Engineered Barrier

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.

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 Large-Scale Additive Manufacturing for Low Cost Small-Scale Wind Turbine Manufacturing

2020 ◽  
Author(s):  
Brian Post ◽  
Phillip Chesser ◽  
Alex Roschli ◽  
Lonnie Love ◽  
Katherine Gaul
Keyword(s):  
Additive Manufacturing ◽  
Wind Turbine ◽  
Large Scale ◽  
Low Cost ◽  
Small Scale

scholarly journals Variational data assimilation with superparameterization

2015 ◽  
Vol 2 (2) ◽  
pp. 513-536 ◽  
Author(s):  
I. Grooms ◽  
Y. Lee
Keyword(s):  
Data Assimilation ◽  
Large Scale ◽  
Climate Models ◽  
Low Cost ◽  
Ocean Model ◽  
Variational Data Assimilation ◽  
Scale Model ◽  
Small Scale ◽  
New Applications ◽  
Lorenz 96

Abstract. Superparameterization (SP) is a multiscale computational approach wherein a large scale atmosphere or ocean model is coupled to an array of simulations of small scale dynamics on periodic domains embedded into the computational grid of the large scale model. SP has been successfully developed in global atmosphere and climate models, and is a promising approach for new applications. The authors develop a 3D-Var variational data assimilation framework for use with SP; the relatively low cost and simplicity of 3D-Var in comparison with ensemble approaches makes it a natural fit for relatively expensive multiscale SP models. To demonstrate the assimilation framework in a simple model, the authors develop a new system of ordinary differential equations similar to the two-scale Lorenz-'96 model. The system has one set of variables denoted {Yi}, with large and small scale parts, and the SP approximation to the system is straightforward. With the new assimilation framework the SP model approximates the large scale dynamics of the true system accurately.

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.

STYLE: Study on Transferability of Fracture Material Properties From Small Scale Specimens to a Real Component

2011 ◽  
Author(s):  
Tomas Nicak ◽  
Herbert Schendzielorz ◽  
Elisabeth Keim ◽  
Gottfried Meier
Keyword(s):  
Fracture Mechanics ◽  
Material Properties ◽  
Large Scale ◽  
Fracture Behaviour ◽  
Experimental Investigations ◽  
Small Scale ◽  
Real Component ◽  
Material Data ◽  
Analytical Work ◽  
Constraint Effects

This paper describes numerical and experimental investigations on transferability of material properties obtained by testing of small scale specimens to a real component. The presented study is related to the experimental and analytical work performed on Mock-up3, which is one of three unique large scale Mock-ups tested within the European project STYLE. Mock-up3 is foreseen to investigate transferability of material data, in particular fracture mechanics properties. An important part of this work is to study constraint effects on different small scale specimens and to compare their fracture behaviour with the fracture behaviour of a large scale (component like) structure. The Mock-Up3 is an original part of a surge line made of low alloy steel 20 MnMoNi 5 5 (which corresponds to SA 508 Grade 3, Cl. 1). The goal of the test is to introduce stable crack growth of an inner surface flaw until a break through the wall occurs. To design such a test reliable fracture mechanics material properties must be available. Usually, these material data are obtained by testing small specimens, which are subsequently used for the assessment of a large scale structure (component). This is being done under the assumption that these “small scale” material properties are fully transferable to “large scale” components. It is assumed that crack initiation in the ductile tearing regime is rather independent of the crack shape, a/W ratio, loading condition or size of the specimen (constraint effects). In order to check the aforementioned assumption and to improve understanding of the physical process leading to failure of cracked components comprehensive experimental and analytical work is being undertaken in STYLE. This paper summarizes Up-To-Date available results, which have been achieved during the first 15 months of the project.

scholarly journals Gloxinia—An Open-Source Sensing Platform to Monitor the Dynamic Responses of Plants

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3055
Author(s):  
Olivier Pieters ◽  
Tom De Swaef ◽  
Peter Lootens ◽  
Michiel Stock ◽  
Isabel Roldán-Ruiz ◽  
...  
Keyword(s):  
Open Source ◽  
Large Scale ◽  
Environmental Changes ◽  
Low Cost ◽  
Current Data ◽  
Dynamic Responses ◽  
Small Scale ◽  
Data Logging ◽  
Short Term ◽  
Sensing Platforms

The study of the dynamic responses of plants to short-term environmental changes is becoming increasingly important in basic plant science, phenotyping, breeding, crop management, and modelling. These short-term variations are crucial in plant adaptation to new environments and, consequently, in plant fitness and productivity. Scalable, versatile, accurate, and low-cost data-logging solutions are necessary to advance these fields and complement existing sensing platforms such as high-throughput phenotyping. However, current data logging and sensing platforms do not meet the requirements to monitor these responses. Therefore, a new modular data logging platform was designed, named Gloxinia. Different sensor boards are interconnected depending upon the needs, with the potential to scale to hundreds of sensors in a distributed sensor system. To demonstrate the architecture, two sensor boards were designed—one for single-ended measurements and one for lock-in amplifier based measurements, named Sylvatica and Planalta, respectively. To evaluate the performance of the system in small setups, a small-scale trial was conducted in a growth chamber. Expected plant dynamics were successfully captured, indicating proper operation of the system. Though a large scale trial was not performed, we expect the system to scale very well to larger setups. Additionally, the platform is open-source, enabling other users to easily build upon our work and perform application-specific optimisations.

scholarly journals Displacement Study of a Large-Scale Freeform Timber Plate Structure Using a Total Station and a Terrestrial Laser Scanner

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 413 ◽  
Author(s):  
Anh Chi Nguyen ◽  
Yves Weinand
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Laser Scanner ◽  
Experimental Tests ◽  
Point Clouds ◽  
Element Model ◽  
Experimental Investigations ◽  
Bottom Surface ◽  
Terrestrial Laser Scanner ◽  
Total Station

Recent advances in timber construction have led to the realization of complex timber plate structures assembled with wood-wood connections. Although advanced numerical modelling tools have been developed to perform their structural analysis, limited experimental tests have been carried out on large-scale structures. However, experimental investigations remain necessary to better understand their mechanical behaviour and assess the numerical models developed. In this paper, static loading tests performed on timber plate shells of about 25 m span are reported. Displacements were measured at 16 target positions on the structure using a total station and on its entire bottom surface using a terrestrial laser scanner. Both methods were compared to each other and to a finite element model in which the semi-rigidity of the connections was represented by springs. Total station measurements provided more consistent results than point clouds, which nonetheless allowed the visualization of displacement fields. Results predicted by the model were found to be in good agreement with the measurements compared to a rigid model. The semi-rigid behaviour of the connections was therefore proven to be crucial to precisely predict the behaviour of the structure. Furthermore, large variations were observed between as-built and designed geometries due to the accumulation of fabrication and construction tolerances.

Community Monitoring Improves Public Service Provision at Scale: Experimental Evidence from a Child Development Program in Nicaragua

2020 ◽  
Author(s):  
Florencia López Boo ◽  
Jane Leer ◽  
Akito Kamei
Keyword(s):  
Child Development ◽  
Experimental Evidence ◽  
Large Scale ◽  
Service Providers ◽  
Low Cost ◽  
Development Program ◽  
Small Scale ◽  
Community Monitoring ◽  
Quality Assurance Mechanism ◽  
Intent To Treat

Expanding small-scale interventions without lowering quality and attenuating impact is a critical policy challenge. Community monitoring overs a low-cost quality assurance mechanism by making service providers account-able to local citizens, rather than distant administrators. This paper provides experimental evidence from a home visit parenting program implemented at scale by the Nicaraguan government, with two types of monitoring: (a) institutional monitoring; and (b) community monitoring. We find d a positive intent-to-treat effect on child development, but only among groups randomly assigned to community monitoring. Our findings show promise for the use of community monitoring to ensure quality in large-scale government-run social programs.

scholarly journals Impinging jets – a short review on strategies for heat transfer enhancement

2018 ◽  
Vol 32 ◽  
pp. 01013
Author(s):  
Ilinca Nastase ◽  
Florin Bode
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Short Review ◽  
Great Difficulty ◽  
Impinging Jets ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Small Scale ◽  
Strong Shear ◽  
Flow Phenomena

In industrial applications, heat and mass transfer can be considerably increased using impinging jets. A large number of flow phenomena will be generated by the impinging flow, such as: large scale structures, large curvature involving strong shear and normal stresses, stagnation in the wall boundary layers, heat transfer with the impinged wall, small scale turbulent mixing. All these phenomena are highly unsteady and even if nowadays a substantial number of studies in the literature are dedicated, the impinging jets are still not fully understood due to the highly unsteady nature and more over due to great difficulty of performing detailed numerical and experimental investigations.

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