A Parametric Approach for Determining Fishway Attraction Flow at Hydropower Dams

High discharges at hydropower plants (HPP) may mask fishway attraction flows and, thereby, prevent fishes from locating and using fishways critical for their access to upstream spawning and rearing habitats. Existing methods for determining attraction flows are either based on simple guidelines (e.g., a proportion of HPP discharge) that cannot address the spatial and temporal complexity of tailrace flow patterns or complicated studies (e.g., combinations of detailed hydraulic and biological investigations) that are expensive and time-consuming. To bridge this gap, we present a new, intermediate approach to reliably determine attraction flows for technical fishways at small to medium-sized waterways (mean annual flow up to 400 m3/s). Fundamental to our approach is a design criterion that the attraction flow should maintain its integrity as it propagates downstream from the fishway entrance to beyond the highly turbulent zone characteristic of HPP tailraces to create a discernable migration corridor connecting the fishway entrance to the downstream river. To implement this criterion, we describe a set of equations to calculate the width of the entrance and the corresponding attraction discharge. Input data are usually easy to obtain and include geometrical and hydraulic parameters describing the target HPP and its tailrace. To confirm our approach, we compare model results to four sites at German waterways where the design of attraction flow was obtained by detailed experimental and numerical methods. The comparison shows good agreement supporting our approach as a useful, intermediate alternative for determining attraction flows that bridges the gap between simple guidelines and detailed hydraulic and biological investigations.

Estimation of Carbon Dioxide emissions along an active fault by using geoelectrical measurements

<p>In the last twenty years, a growing interest is noticed in quantifying non-volcanic degassing, which could represent a significant input of CO<sub>2</sub> into the atmosphere. Large emissions of non-volcanic carbon dioxide usually take place in seismically active zones, where the existence of a positive spatial correlation between gas discharges and extensional tectonic regimes has been confirmed by seismic data. Extensional stress plays a key role in creating pathways for the rising of gases at micro- and macro-scales, increasing the rock permeability and connecting the deep crust to the earth surface. Geoelectrical investigations, which are very sensitive to permeability changes, provide accurate volumetric reconstructions of the physical properties of the rocks and, therefore, are fundamental not only for the definition of the seismic-active zone geometry, but also for understanding the processes that govern the flow of fluids along the damage zone. In this framework, we present the results of an integrated approach where geoelectrical and passive seismic data are used to construct a 3D geological model, whose simulated temporal evolution allowed the estimation of CO<sub>2</sub> flux along an active fault in the area of Matese Ridge (Southern Apennines, Italy). By varying the geometry of the source system and the permeability values of the damage zone, characteristic times for the upward migration of CO<sub>2</sub> through a thick layer of silts and clays have been estimated and CO<sub>2</sub> fluxes comparable with the observed values in the investigated area have been predicted. These findings are promising for gas hazard, as they suggest that numerical simulations of different CO<sub>2</sub> degassing scenarios could forecast possible critical variations in the amount of CO<sub>2</sub> emitted near the fault.</p>

Review Kuat Tekan Beton Polos dari Perspektif Mekanika Fraktur

Concrete is a discreet material that consist of aggregate as filler and cement paste (matrix) as binder. Both of them work together as a composite or monolithic mechanism, depends on the interface zone characteristic that developed by aggregate. Monolithic mechanism leading to failure catastrophically (brittle and instantly), while composite mechanism prevails failure occurs gradually. Monolithic mechanism maybe found in high strength concrete where hardness and stiffness of aggregate are compatible with their matrix. At the moment when the matrix tensile strength (ft) is reached. The cracks will propagate quickly cutting both aggregates and matrix, as well at once. Contrary to the composite condition, when the matrix tensile strength is reached, the aggregate will take over the load and the crack will propagate through the interface zone. The perspective of fracture mechanics and the failure parameters explain the mechanism of crack propagation based on the energy principles. This investigation reviews the phenomenon of concrete compressive strength with angular aggregates compared to rounded aggregates on cylindrical specimens with diameter (d) 15 cm and height (h) 30 cm of the same compressive strength. The difference between them, shows the tendency of the influence of the interface zone as traction, which significantly contributes to the performance capacity before collapse

Isolation of Ethidium Bromide Degrading Bacteria from Jharkhand

Ethidium bromide (EtBr) is a carcinogenic and mutagenic agent which is widely used in research laboratories to probe nucleic acids by gel electrophoresis. It is generally buried underground (for solid waste) or disposed of pouring it down the sink (in case of liquid waste). Soil or drain microbial community may be able to take care of such substance else it will lead to contamination of our underground resources or others through defined and undefined routes. In view of the above assumption and literature reports the present study was undertaken to isolate and evaluate bacteria for removal, by bioaccumulation and /or biotransformation, of EtBr from contaminated sources and wastes, before their disposal to the environment. Two distinct bacteria both motile BR3 and BR4 could be identified from agarose-gel-waste containing 0.5-1.0 µg/ml ethidium bromide. Both bacteria were found to grow on EtBr-NA plate (Nutrient-Agar supplemented with EtBr at a concentration of 30 µg/ml) however only BR3 isolate showed large non-fluorescent-halo zone (characteristic to degradation of EtBr) when exposed to trans-UV light. Other isolate BR4 could accumulate EtBr within the colony biomass but did not showed clear (non-fluorescent) hallow zone around it. However the bacterium is not able to utilize the EtBr as a sole carbon source.Int. J. Appl. Sci. Biotechnol. Vol 5(3): 293-301

Visual City's Colour Design-Taking the Studying of Wuhan City Colour as an Example

With the rapid development of Chinas modernization construction, the planning of the citys colour landscape plays an important role in keeping urban view feature, enriching urban cultural connotation and enhancing urban quality. This paper is based on the visual, the colour and urban environment creative view. It is necessary to design urban colour plan within detailed plan because of the complexity of the colour itself. Its also essential to develop the method for urban colour landscape is an important part of city aesthetics to promote the level of urban construction. To sum up, this paper takes Wuhan city colour as an example. The building colour of Wuhan city is divided into central zone, transition zone, diffusion zone, characteristic area, form area, i.e. five regional colour partitions. It establishes the main tone of the urban design and builds 50 city building colour control area. The paper broaches control rules for the citys colour design and administration advice for the citys colour design. This study provides a systematic colour planning method which can be put into practice.

Modelling historical and recent mass loss of McCall Glacier, Alaska, USA

Volume loss of valley glaciers is now considered to be a significant contribution to sea level rise. Understanding and identifying the processes involved in accelerated mass loss are necessary to determine their impact on the global system. Here we present results from a series of model experiments with a higher-order thermomechanically coupled flowline model (Pattyn, 2002). Boundary conditions to the model are parameterizations of surface mass balance, geothermal heating, observed surface and 10 m ice depth temperatures. The time-dependent experiments aim at simulating the glacier retreat from its LIA expansion to present according to different scenarios and model parameters. Model output was validated against measurements of ice velocity, ice surface elevation and terminus position at different stages. Results demonstrate that a key factor in determining the glacier retreat history is the importance of internal accumulation (>50%) in the total mass balance. The persistence of a basal temperate zone characteristic for this polythermal glacier depends largely on its contribution. Accelerated glacier retreat since the early nineties seems directly related to the increase in ELA and the sudden reduction in AAR due to the fact that a large lower elevation cirque – previously an important accumulation area – became part of the ablation zone.

Modelling historical and recent mass loss of McCall Glacier, Alaska, USA

Volume loss of valley glaciers is now considered to be a significant contribution to sea level rise. Understanding and identifying the processes involved in accelerated mass loss are necessary to determine their impact on the global system. Here we present results from a series of model experiments with a higher-order thermomechanically coupled flowline model (Pattyn, 2002). Boundary conditions to the model are parameterizations of surface mass balance, geothermal heating, observed surface and 10 m ice depth temperatures. The time-dependent experiments aim at simulating the glacier retreat from its LIA expansion to present according to different scenarios and model parameters. Model output was validated against measurements of ice velocity, ice surface elevation and terminus position at different stages. Results demonstrate that a key factor in determining the glacier retreat history is the importance of internal accumulation (>50%) in the total mass balance. The persistence of a basal temperate zone characteristic for this polythermal glacier depends largely on its contribution. Accelerated glacier retreat since the early nineties seems directly related to the increase in ELA and the sudden reduction in AAR due to the fact that a large lower elevation cirque – previously an important accumulation area – became part of the ablation zone.