An Experimental Investigation of the Hydraulics and Pollutant Dispersion Characteristics of a Model Beaver Dam

Beavers have influenced the world’s ecosystem for millions of years. Their dams create ponds and wetlands that provide a large range of hydraulic and ecological benefits to the natural world, including mitigation against flooding and improving water quality. As beavers are now being reintroduced to many parts of the world, it is important to fully understand the impact of their dams on the flow characteristics of the water-courses on which they are built. This paper investigates the relationship between the physical properties of a model beaver dam and its fundamental hydraulics and pollutant dispersion characteristics. The first objective of this paper was to develop a modelling framework to relate discharge to flow-depth for dams with a combination of porous and impermeable sections. The second objective was to utilize a similar framework to predict the down-stream concentration distribution of an up-stream pollution event passing through such systems. The ability to model these parameters for dams with variable lengths of porous and impermeable sections is important as the porosity of beaver dams can vary with depth, depending on which sections are constructed from branches, rocks, or compacted mud. The analysis and modelling developed in this paper show that a single, general relationship can be obtained between discharge and flow-depth regardless of the presence of sections that are both porous or impermeable, provided the relative depths of these sections are known and accounted for. It is also shown that the Nominal Residence Time and the Advection Dispersion Equation can be used to predict pollutant transport in such systems. These two equations have previously been shown to have limitations when applied to some complex systems, so demonstrating they can be applied to a porous dam with combinations of porous and impermeable sections at the relative discharges investigated is noteworthy.

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Deterministic approach for multiple-source tsunami hazard assessment for Sines, Portugal

Natural Hazards and Earth System Science ◽

10.5194/nhess-15-2557-2015 ◽

2015 ◽

Vol 15 (11) ◽

pp. 2557-2568 ◽

Cited By ~ 11

Author(s):

M. Wronna ◽

R. Omira ◽

M. A. Baptista

Keyword(s):

Sea Level ◽

Wave Height ◽

Hazard Assessment ◽

Test Site ◽

Tsunami Hazard ◽

Deterministic Approach ◽

Flow Depth ◽

Mean Sea Level ◽

Tsunami Hazard Assessment ◽

The Impact

Abstract. In this paper, we present a deterministic approach to tsunami hazard assessment for the city and harbour of Sines, Portugal, one of the test sites of project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). Sines has one of the most important deep-water ports, which has oil-bearing, petrochemical, liquid-bulk, coal, and container terminals. The port and its industrial infrastructures face the ocean southwest towards the main seismogenic sources. This work considers two different seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, we selected a total of six scenarios to assess the tsunami impact at the test site. The tsunami simulations are computed using NSWING, a Non-linear Shallow Water model wIth Nested Grids. In this study, the static effect of tides is analysed for three different tidal stages: MLLW (mean lower low water), MSL (mean sea level), and MHHW (mean higher high water). For each scenario, the tsunami hazard is described by maximum values of wave height, flow depth, drawback, maximum inundation area and run-up. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at the Sines test site considering the single scenarios at mean sea level, the aggregate scenario, and the influence of the tide on the aggregate scenario. The results confirm the composite source of Horseshoe and Marques de Pombal faults as the worst-case scenario, with wave heights of over 10 m, which reach the coast approximately 22 min after the rupture. It dominates the aggregate scenario by about 60 % of the impact area at the test site, considering maximum wave height and maximum flow depth. The HSMPF scenario inundates a total area of 3.5 km2.

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The impact of urban block typology on pollutant dispersion

Journal of Wind Engineering and Industrial Aerodynamics ◽

10.1016/j.jweia.2021.104524 ◽

2021 ◽

Vol 210 ◽

pp. 104524

Author(s):

Fabiana Trindade da Silva ◽

Neyval Costa Reis ◽

Jane Meri Santos ◽

Elisa Valentim Goulart ◽

Cristina Engel de Alvarez

Keyword(s):

Pollutant Dispersion ◽

The Impact

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An improved de Laval nozzle experiment

International Journal of Mechanical Engineering Education ◽

10.1177/03064190211034165 ◽

2021 ◽

pp. 030641902110341

Author(s):

Nicholas Goodman ◽

Brian J Leege ◽

Peter E Johnson

Keyword(s):

Data Acquisition ◽

Laval Nozzle ◽

Flow Characteristics ◽

Data Acquisition System ◽

Isentropic Flow ◽

Hands On ◽

De Laval Nozzle ◽

Physical Phenomena ◽

The Impact ◽

The Relationship

Exposing students to hands-on experiments has been a common approach to illustrating complex physical phenomena that have been otherwise modelled solely mathematically. Compressible, isentropic flow in a duct is an example of such a phenomenon, and it is often demonstrated via a de Laval nozzle experiment. We have improved an existing converging/diverging nozzle experiment so that students can modify the location of the normal shock that develops in the diverging portion to better understand the relationship between the shock and the pressure. We have also improved the data acquisition system for this experiment and explained how visualisation of the standing shock is now possible. The results of the updated system demonstrate that the accuracy of the isentropic flow characteristics has not been lost. Through pre- and post-laboratory quizzes, we show the impact on student learning as well.

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The flow characteristics around bridge piers under the impact of a ship

Journal of Hydrodynamics ◽

10.1007/s42241-020-0082-5 ◽

2020 ◽

Vol 32 (6) ◽

pp. 1165-1177

Author(s):

Yan-fen Geng ◽

Hua-qiang Guo ◽

Xing Ke

Keyword(s):

Flow Characteristics ◽

Bridge Piers ◽

The Impact

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Virus Transmission Risk in Urban Rail Systems: Microscopic Simulation-Based Analysis of Spatio-Temporal Characteristics

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211010181 ◽

2021 ◽

pp. 036119812110101

Author(s):

Jiali Zhou ◽

Haris N. Koutsopoulos

Keyword(s):

Public Transportation ◽

Virus Transmission ◽

Flow Characteristics ◽

Transportation Systems ◽

Transmission Risk ◽

Microscopic Simulation ◽

Spatial And Temporal Patterns ◽

Subway System ◽

Public Transportation Systems ◽

The Impact

The transmission risk of airborne diseases in public transportation systems is a concern. This paper proposes a modified Wells-Riley model for risk analysis in public transportation systems to capture the passenger flow characteristics, including spatial and temporal patterns, in the number of boarding and alighting passengers, and in number of infectors. The model is used to assess overall risk as a function of origin–destination flows, actual operations, and factors such as mask-wearing and ventilation. The model is integrated with a microscopic simulation model of subway operations (SimMETRO). Using actual data from a subway system, a case study explores the impact of different factors on transmission risk, including mask-wearing, ventilation rates, infectiousness levels of disease, and carrier rates. In general, mask-wearing and ventilation are effective under various demand levels, infectiousness levels, and carrier rates. Mask-wearing is more effective in mitigating risks. Impacts from operations and service frequency are also evaluated, emphasizing the importance of maintaining reliable, frequent operations in lowering transmission risks. Risk spatial patterns are also explored, highlighting locations of higher risk.

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Attributional & Consequential Life Cycle Assessment: Definitions, Conceptual Characteristics and Modelling Restrictions

Sustainability ◽

10.3390/su13137386 ◽

2021 ◽

Vol 13 (13) ◽

pp. 7386

Author(s):

Thomas Schaubroeck ◽

Simon Schaubroeck ◽

Reinout Heijungs ◽

Alessandra Zamagni ◽

Miguel Brandão ◽

...

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Environmental Impact ◽

Product Life Cycle ◽

Sustainability Assessment ◽

Consequential Life Cycle Assessment ◽

Modelling Framework ◽

Potential Environmental Impact ◽

Reference Environment ◽

The Impact

To assess the potential environmental impact of human/industrial systems, life cycle assessment (LCA) is a very common method. There are two prominent types of LCA, namely attributional (ALCA) and consequential (CLCA). A lot of literature covers these approaches, but a general consensus on what they represent and an overview of all their differences seems lacking, nor has every prominent feature been fully explored. The two main objectives of this article are: (1) to argue for and select definitions for each concept and (2) specify all conceptual characteristics (including translation into modelling restrictions), re-evaluating and going beyond findings in the state of the art. For the first objective, mainly because the validity of interpretation of a term is also a matter of consensus, we argue the selection of definitions present in the 2011 UNEP-SETAC report. ALCA attributes a share of the potential environmental impact of the world to a product life cycle, while CLCA assesses the environmental consequences of a decision (e.g., increase of product demand). Regarding the second objective, the product system in ALCA constitutes all processes that are linked by physical, energy flows or services. Because of the requirement of additivity for ALCA, a double-counting check needs to be executed, modelling is restricted (e.g., guaranteed through linearity) and partitioning of multifunctional processes is systematically needed (for evaluation per single product). The latter matters also hold in a similar manner for the impact assessment, which is commonly overlooked. CLCA, is completely consequential and there is no limitation regarding what a modelling framework should entail, with the coverage of co-products through substitution being just one approach and not the only one (e.g., additional consumption is possible). Both ALCA and CLCA can be considered over any time span (past, present & future) and either using a reference environment or different scenarios. Furthermore, both ALCA and CLCA could be specific for average or marginal (small) products or decisions, and further datasets. These findings also hold for life cycle sustainability assessment.

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“We Make Our Community”: Youth Forging Environmental Identities in Urban Landscapes

Sustainability ◽

10.3390/su13147736 ◽

2021 ◽

Vol 13 (14) ◽

pp. 7736

Author(s):

Erin Gallay ◽

Alisa Pykett ◽

Constance Flanagan

Keyword(s):

High School Students ◽

Urban Areas ◽

Local Environment ◽

Natural World ◽

Urban Landscapes ◽

Youth Of Color ◽

School Students ◽

Environmental Leadership ◽

And Gender ◽

The Impact

Insofar as race, class, and gender have profound effects on people’s environmental experiences, and consequently their activism, the environmental field needs more work on the environmental experiences and insights of groups whose voices have been missing, including youth of color who live in urban areas in the U.S. In this paper, we focus on African American and Latinx students engaged in environmental projects in their urban communities and the impact of such projects on promoting pro-environmental leadership, agency, and behavior. We draw from written reflections and focus group interviews of several hundred 4th–12th graders (majority middle- and high-school students) who participated in place-based civic science projects. Thematic analyses of student responses found that students engaged in work on local environmental issues cultivated an appreciation for the natural world and an understanding of human-nature interdependence and the ties between the local environment and their communities’ health. Through taking action with others in their communities, students viewed themselves as contributors to their communities and started to form environmental identities in ways that are not traditionally measured. Findings point to the need for forms of environmental education that are contextually grounded and centered on environmental justice in urban areas.

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Airflow Characteristics According to the Change in the Height and Porous Rate of Building Roofs for Efficient Installation of Small Wind Power Generators

Sustainability ◽

10.3390/su13105688 ◽

2021 ◽

Vol 13 (10) ◽

pp. 5688

Author(s):

Jangyoul You ◽

Kipyo You ◽

Minwoo Park ◽

Changhee Lee

Keyword(s):

Wind Speed ◽

Wind Power ◽

Turbulence Intensity ◽

Flow Characteristics ◽

High Porosity ◽

Power Generators ◽

Speed Reduction ◽

Reduction Effect ◽

Wind Power Generators ◽

The Impact

In this paper, the air flow characteristics and the impact of wind power generators were analyzed according to the porosity and height of the parapet installed in the rooftop layer. The wind speed at the top was decreasing as the parapet was installed. However, the wind speed reduction effect was decreasing as the porosity rate increased. In addition, the increase in porosity significantly reduced turbulence intensity and reduced it by up to 40% compared to no railing. In the case of parapets with sufficient porosity, the effect of reducing turbulence intensity was also increased as the height increased. Therefore, it was confirmed that sufficient parapet height and high porosity reduce the effect of reducing wind speed by parapets and significantly reducing the turbulence intensity, which can provide homogeneous wind speed during installation of wind power generators.

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The impact of convergent technologies on changing labor markets

KANT ◽

10.24923/2222-243x.2020-37.52 ◽

2020 ◽

Vol 37 (4) ◽

pp. 240-245

Author(s):

Tatiana Vorontsova

Keyword(s):

Labor Market ◽

Social Relations ◽

Technological Development ◽

Natural World ◽

Social Rights ◽

Physical Strength ◽

Humanistic Approach ◽

The One ◽

The Impact

The article analyzes the problems of the development of convergent technologies, which, on the one hand, make it possible to overcome the natural limitations of man and expand his capabilities, on the other hand, threaten humanity. The author identifies various research positions in assessing the prospects for NBIC convergence - from overtly alarmist to overly enthusiastic. A classification of possible results of technological innovations is proposed, in which changes in the natural world, the technical environment and the transformation of social relations and spiritual and moral values are highlighted. Trends in the labor market are noted such as job cuts due to automation, the polarization of the labor market for highly paid intellectual workers and cheap physical strength, the emergence of new professions that require special education in several areas, changes in the organization of labor by the type of network interaction, the emergence of new forms of employment - temporary, deprived of guarantees and infringing on social rights. The future labor market is characterized as fragmented and isolated. The conclusion is drawn about the need for a humanistic approach in assessing the prospects of technological development.

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