scholarly journals Upstream passage of adult sea trout (Salmo trutta) at a low-head weir with an Archimedean screw hydropower turbine and co-located fish pass

2018 ◽  
Vol 69 (12) ◽  
pp. 1822 ◽  
Author(s):  
Jamie R. Dodd ◽  
Jonathan D. Bolland ◽  
Jon Hateley ◽  
Ian G. Cowx ◽  
Sam E. Walton ◽  
...  
Keyword(s):  
Salmo Trutta ◽  
Best Practice ◽  
Fish Passage ◽  
Green Energy ◽  
Small Scale ◽  
Sea Trout ◽  
Fish Pass ◽  
Wide Range ◽  
Negative Effect ◽  
Low Head

The exploitation of riverine systems for renewable energy has resulted in large numbers of small-scale hydropower schemes on low-head weirs. Although considered a clean and ‘green’ energy source in terms of emissions, hydropower can affect upstream migrating species by diverting flow away from viable routes over the impoundment and attract fish towards the turbine outfall. In an attempt to reduce this negative effect, hydropower outfalls with co-located fish-passage entrances are recommended, utilising turbine flows to attract fish towards the fish pass. The present study used acoustic telemetry to understand the performance of a co-located Larinier fish pass at a low-head hydropower scheme at a weir on the tidal Yorkshire Esk, England. The majority of the sea trout (anadromous Salmo trutta L.) individuals that approached the impediment were attracted to the hydropower and the co-located fish pass. Fish ascended through the pass under a wide range of river flows, tide heights, downstream river levels and hydropower flows, and there was no evidence that the hydropower operation affected fish-pass ascent. The information presented is urgently required to inform management decisions on the operation of hydropower schemes during the migratory period of salmonid fish, and help determine best-practice designs and operation at these facilities.

Spawning site selection and redd gravel characteristics of sea trout Salmo trutta in the lowland streams of Lithuania

2011 ◽  
Vol 40 (1) ◽  
Author(s):  
Nerijus Nika ◽  
Tomas Virbickas ◽  
Antanas Kontautas
Keyword(s):  
Site Selection ◽  
Salmo Trutta ◽  
Habitat Preferences ◽  
Scientific Basis ◽  
Spawning Habitat ◽  
Lowland Streams ◽  
Sea Trout ◽  
Spawning Site ◽  
Unit Scale ◽  
Wide Range

AbstractTo date, no characterization of spawning habitats on scientific basis was made for the eastern Baltic salmonid populations. The aim of the present study was to characterize spawning habitat preferences and redd gravel structure of sea trout in lowland streams of western Lithuania. The redd position at the habitat-unit scale, microhabitat hydrological characteristics and the redd gravel structure have been analyzed. The spawning site selection by sea trout was related to the in-stream characteristics, but not to the riparian features. Redds were positioned mainly in the transitional pool-riffle zones, associated with close proximity to potential cover for spawners. At the microhabitat scale, sites with relatively consistent hydrological parameters (mode of water depth 0.25–0.40 m, flow velocity 0.4–0.7 m s−1 and Froude number 0.2–0.4) were selected from a wide range of available sites. Egg incubation conditions, in terms of the redd gravel structure in the spring, were of intermediate quality, while varied widely within particular reaches. According to the results of the present study, it is apparent that sea trout have particular preferences for spawning sites, which should be considered in emerging river-restoration projects.

scholarly journals Archimedean screw as fish-friendly turbines for harnessing hydropower potential

2021 ◽  
Vol 286 ◽  
pp. 02007
Author(s):  
Cristian Purece ◽  
Lilica Corlan
Keyword(s):  
Renewable Energy ◽  
Renewable Energy Sources ◽  
Energy System ◽  
Fish Passage ◽  
Green Energy ◽  
Hydropower Plants ◽  
Hydropower Potential ◽  
Low Head ◽  
High Head

Hydraulic energy is one of the most important sources of renewable energy today. It is also a complementary source to other renewable energy sources, being the only one that offers an important nonpolluting storage capacity (through pump storage facilities). Another essential quality of hydraulic energy is its ability to regulate the energy system to allow the integration of other sources, in which the process of generating energy depends on factors that cannot be controlled (sun, wind, etc.). However, hydropower plants can damage ecosystems, especially by affecting fish within their turbines. Usually, fish cannot pass unharmed through most of the turbines. The main exceptions generally include some low head (below 8 m) turbines, such as the Very Low Head (VLH) turbine and the screw turbine, but lately strategies have also been developed for high head hydropower plants such as: fish passage facilities and fish friendly turbines such as Alden turbine, Minimal Gap Runner turbine (MGR). However, this article only deals with screw-type turbines, low-head fish-friendly turbines and how to implement them in order to obtain sustainable green energy.

Research on the Economic Organization Environmental Impact

2017 ◽  
Vol 68 (3) ◽  
pp. 599-601
Author(s):  
Dan Paul Stefanescu ◽  
Oana Roxana Chivu ◽  
Claudiu Babis ◽  
Augustin Semenescu ◽  
Alina Gligor
Keyword(s):  
Economic Activity ◽  
Economic Organization ◽  
Economic Activities ◽  
Environmental Implications ◽  
Minimal Impact ◽  
Wide Range ◽  
Material Environment ◽  
Negative Effect ◽  
Harmful Effects

Any economic activity carried out by an organization, can generate a wide range of environmental implications. Particularly important, must be considered the activities that have a significant negative effect on the environment, meaning those which pollute. Being known the harmful effects of pollution on the human health, the paper presents two models of utmost importance, one of the material environment-economy interactions balance and the other of the material flows between environmental factors and socio-economic activities. The study of these models enable specific conditions that must be satisfied for the economic processes friendly coexist to the environment for long term, meaning to have a minimal impact in that the residues resulting from the economic activity of the organization to be as less harmful to the environment.

Present Status of the Salmonids Atlantic Salmon and Sea-Trout in the Dutch Part of the River Rhine

1994 ◽  
Vol 29 (3) ◽  
pp. 37-41 ◽  
Author(s):  
W. G. Cazemier
Keyword(s):  
Atlantic Salmon ◽  
Salmo Trutta ◽  
Natural Populations ◽  
River Rhine ◽  
Sea Trout ◽  
The Past ◽  
The North ◽  
Trout Population ◽  
The North Sea ◽  
Heavy Pollution

In the past, the anadromous salmonids, Atlantic salmon (Salmo salar) and sea-trout (Salmo trutta), have formed natural populations in the river Rhine. From the beginning of the nineteenth century onwards, the greater part of the drainage area of the river has been gradually altered from a more or less rural and agricultural area, into a highly industrialised one with subsequent industrialisation, river-engineering and heavy pollution. These developments are considered to be the major cause for the disappearance of the populations of anadromous salmonid fish in the 1950s. The water quality has recovered significantly during the past 25 years. From about 1975 onwards, this process gave rise to a recovery of the anadromous trout population. Results of recent studies of the sea-trout migration pattern are presented. They reveal that nowadays these salmonids can complete their up- and downstream migrations from the North Sea to places, situated at hundreds of kilometres upward the river and vica versa. The numbers of recorded Atlantic salmon and catch locations in inland waters are presented. They show a significant increase since 1989. These phenomena can be understood as promising signs of the recovery of the Rhine aquatic ecosystem.

Associated microflora of medicinal ferns: biotechnological potentials and possible applications

2016 ◽  
Vol 5 (03) ◽  
pp. 4927 ◽  
Author(s):  
Shubhi Srivastava ◽  
Paul A. K.
Keyword(s):  
Secondary Metabolites ◽  
Growth Promotion ◽  
Biological Activities ◽  
Hydrolytic Enzymes ◽  
In Vitro Production ◽  
Wide Range ◽  
Negative Effect ◽  
Bacteria And Fungi

Plant associated microorganisms that colonize the upper and internal tissues of roots, stems, leaves and flowers of healthy plants without causing any visible harmful or negative effect on their host. Diversity of microbes have been extensively studied in a wide variety of vascular plants and shown to promote plant establishment, growth and development and impart resistance against pathogenic infections. Ferns and their associated microbes have also attracted the attention of the scientific communities as sources of novel bioactive secondary metabolites. The ferns and fern alleles, which are well adapted to diverse environmental conditions, produce various secondary metabolites such as flavonoids, steroids, alkaloids, phenols, triterpenoid compounds, variety of amino acids and fatty acids along with some unique metabolites as adaptive features and are traditionally used for human health and medicine. In this review attention has been focused to prepare a comprehensive account of ethnomedicinal properties of some common ferns and fern alleles. Association of bacteria and fungi in the rhizosphere, phyllosphere and endosphere of these medicinally important ferns and their interaction with the host plant has been emphasized keeping in view their possible biotechnological potentials and applications. The processes of host-microbe interaction leading to establishment and colonization of endophytes are less-well characterized in comparison to rhizospheric and phyllospheric microflora. However, the endophytes are possessing same characteristics as rhizospheric and phyllospheric to stimulate the in vivo synthesis as well as in vitro production of secondary metabolites with a wide range of biological activities such as plant growth promotion by production of phytohormones, siderophores, fixation of nitrogen, and phosphate solubilization. Synthesis of pharmaceutically important products such as anticancer compounds, antioxidants, antimicrobials, antiviral substances and hydrolytic enzymes could be some of the promising areas of research and commercial exploitation.

Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

2013 ◽  
Author(s):  
J. Schiffmann
Keyword(s):  
Design Optimization ◽  
High Efficiency ◽  
Integrated Design ◽  
Heat Pumps ◽  
Small Scale ◽  
Multi Objective Optimization ◽  
Design Constraints ◽  
Multi Objective ◽  
Wide Range ◽  
Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

scholarly journals A broadbanded pressure differential wave energy converter based on dielectric elastomer generators

2021 ◽  
Author(s):  
Michele Righi ◽  
Giacomo Moretti ◽  
David Forehand ◽  
Lorenzo Agostini ◽  
Rocco Vertechy ◽  
...  
Keyword(s):  
Wave Energy ◽  
Large Deformations ◽  
Dielectric Elastomer ◽  
Wave Energy Converter ◽  
Pressure Differential ◽  
Design Stage ◽  
Small Scale ◽  
Energy Converter ◽  
Wide Range ◽  
The Waves

AbstractDielectric elastomer generators (DEGs) are a promising option for the implementation of affordable and reliable sea wave energy converters (WECs), as they show considerable promise in replacing expensive and inefficient power take-off systems with cheap direct-drive generators. This paper introduces a concept of a pressure differential wave energy converter, equipped with a DEG power take-off operating in direct contact with sea water. The device consists of a closed submerged air chamber, with a fluid-directing duct and a deformable DEG power take-off mounted on its top surface. The DEG is cyclically deformed by wave-induced pressure, thus acting both as the power take-off and as a deformable interface with the waves. This layout allows the partial balancing of the stiffness due to the DEG’s elasticity with the negative hydrostatic stiffness contribution associated with the displacement of the water column on top of the DEG. This feature makes it possible to design devices in which the DEG exhibits large deformations over a wide range of excitation frequencies, potentially achieving large power capture in a wide range of sea states. We propose a modelling approach for the system that relies on potential-flow theory and electroelasticity theory. This model makes it possible to predict the system dynamic response in different operational conditions and it is computationally efficient to perform iterative and repeated simulations, which are required at the design stage of a new WEC. We performed tests on a small-scale prototype in a wave tank with the aim of investigating the fluid–structure interaction between the DEG membrane and the waves in dynamical conditions and validating the numerical model. The experimental results proved that the device exhibits large deformations of the DEG power take-off over a broad range of monochromatic and panchromatic sea states. The proposed model demonstrates good agreement with the experimental data, hence proving its suitability and effectiveness as a design and prediction tool.

scholarly journals A Threat of Farmers’ Suicide and the Opportunity in Organic Farming for Sustainable Agricultural Development in India

2019 ◽  
Vol 11 (8) ◽  
pp. 2400 ◽  
Author(s):  
Karthikeyan Mariappan ◽  
Deyi Zhou
Keyword(s):  
Organic Farming ◽  
Tamil Nadu ◽  
Agricultural Development ◽  
Small Scale ◽  
Conventional Farming ◽  
Wide Range ◽  
Significant Difference ◽  
Small Scale Farmers ◽  
The Cost ◽  
Input Cost

Agriculture is the main sources of income for humans. Likewise, agriculture is the backbone of the Indian economy. In India, Tamil Nadu regional state has a wide range of possibilities to produce all varieties of organic products due to its diverse agro-climatic condition. This research aimed to identify the economics and efficiency of organic farming, and the possibilities to reduce farmers’ suicides in the Tamil Nadu region through the organic agriculture concept. The emphasis was on farmers, producers, researchers, and marketers entering the sustainable economy through organic farming by reducing input cost and high profit in cultivation. A survey was conducted to gather data. One way analysis of variance (ANOVA) has been used to test the hypothesis regards the cost and profit of rice production. The results showed that there was a significant difference in profitability between organic and conventional farming methods. It is very transparent that organic farming is the leading concept of sustainable agricultural development with better organic manures that can improve soil fertility, better yield, less input cost and better return than conventional farming. The study suggests that by reducing the cost of cultivation and get a marginal return through organic farming method to poor and small scale farmers will reduce socio-economic problems such as farmers’ suicides in the future of Indian agriculture.

Sign in / Sign up

Export Citation Format

Share Document