A Reliable Tag–Recapture Technique For Estimating Turbine Passage Survival: Application to Young-of-the-Year American Shad (Alosa sapidissima)

1992 ◽  
Vol 49 (9) ◽  
pp. 1826-1834 ◽  
Author(s):  
Paul G. Heisey ◽  
Dilip Mathur ◽  
Ted Rineer
Keyword(s):  
Operating Conditions ◽  
American Shad ◽  
Mitigation Measures ◽  
Long Term Effects ◽  
Mixed Flow ◽  
Alosa Sapidissima ◽  
Hydroelectric Project ◽  
Power Of The Test ◽  
Wide Range ◽  
Test Fish

A new technique (HI-Z Turb'N Tag, U.S. Patent No. 4,970,988) for estimating turbine passage survival was applied to juvenile American shad (Alosa sapidissima) under three operating conditions at a hydroelectric project. Fish are fitted externally with the Turb'N tag and introduced into turbine penstocks. The Turb'N Tag inflates after turbine passage and buoys fish to the surface for recapture and examination; after removal of tags, fish are held to assess long-term effects. Almost all (96%) test (299) and control (300) fish were recovered; average recovery time was less than 9 min. The overall short-term (1 h) survival of test fish, adjusted for control, was 97%; 24- and 48-h survivals were 98 and 94%, respectively. The 48-h survival of test fish was 98–100% for mixed flow and Kaplan turbines and 66.8% for the mixed flow unit in the vented mode. Acute control mortality was negligible (< 5%). Our technique offers several significant advantages over traditional net recapture methods: applicable to wide range of species and size; allows predetermination of statistically valid sample size, level of significance, and power of the test to determine need for mitigation measures; and estimation of cumulative effects of multiple turbine exposure.

Performance Study of a Mixed Flow Impeller Covering an Unsteady Flow Field

1992 ◽  
Vol 206 (2) ◽  
pp. 83-93 ◽  
Author(s):  
S Sarkar
Keyword(s):  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Performance Study ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Wide Range ◽  
Reversal Flow ◽  
Flow Through ◽  
Flow Pump

The results presented here are part of a detailed programme measuring the aerodynamics of a high specific speed mixed flow pump impeller over a wide range of operating conditions, including its behaviour in the unsteady stalled regime. The aim is to elucidate the physics of the flow through such an impeller. The noticeable features are the formation of part-span rotating stall cells having no periodicity and organized structure at reduced flow and also the shifting positions of reversal flow pockets as the flowrate changes. Measurements of loss and its variation with span-wise positions and flowrates enable the variation of local efficiency to be determined. The overall flow picture is similar to that expected in an axial flow impeller, though the present impeller displays a narrow stall hysteresis loop almost right through its operating range.

scholarly journals Evaluating the Use of Leaned Stator Vanes to Produce a Non-Uniform Flow Distribution Across the Inlet Span of a Mixed Flow Turbine Rotor

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Richard Morrison ◽  
Stephen Spence ◽  
Sung In Kim ◽  
Thomas Leonard ◽  
Andre Starke
Keyword(s):  
Leading Edge ◽  
Operating Conditions ◽  
Operating Point ◽  
Mixed Flow ◽  
Design Performance ◽  
Turbine Performance ◽  
Percentage Points ◽  
Wide Range ◽  
Turbine Rotors ◽  
Operating Points

Abstract Current trends in the automotive industry have placed an increased emphasis on downsized turbocharged engines for passenger vehicles. The turbocharger is increasingly relied upon to improve power output across a wide range of engine operating conditions, placing a greater emphasis on turbocharger off-design performance. An off-design condition of significant importance is performance at low turbine velocity ratios, since it is relevant to engine transient response and also to efficient energy extraction from pressure pulses in the unsteady exhaust flow. An increased focus has been placed on equipping turbochargers with mixed flow turbine rotors instead of conventional radial flow turbine rotors to improve off-design performance and to reduce rotor inertia. A recognized feature of a mixed flow turbine is the spanwise variation of flow conditions across the blade leading edge. This is a consequence of the reduction in leading edge radius from shroud to hub, coupled with the increasing tangential velocity of the flow due to conserved angular momentum as the radius decreases. The result is increasingly positive incidence toward the hub side of the leading edge. The resulting region of highly positive incidence at the hub produces separation from the suction surface and generates significant loss within the rotor passage. The aim of this study was to determine if the losses in a mixed flow turbine (MFT) could be reduced by the use of leaned stator vanes, which deliberately created a significant spanwise variation of flow angle between hub and shroud at rotor inlet, to reduce the positive incidence at the hub. The turbine performance with a series of leaned vanes was compared against that of a straight vane using a validated computational fluid dynamics (CFD) model. It was found that increasing vane lean improved turbine performance at all operating points considered. An increase of 3.2 percentage points in stage total-to-static efficiency was achieved at a key off-design operating point. Experimental testing of a set of leaned vanes and the baseline vanes confirmed the advantage of the leaned vanes at all operating points, with an increase in measured efficiency of 2.6 percentage points at the key off-design condition. Unsteady CFD models confirmed the same level of improvement at this operating point. The CFD and experimental results confirmed that the losses in an MFT can be reduced by the use of leaned stator vanes to shape the flow at rotor inlet.

scholarly journals Evaluating the Use of Leaned Stator Vanes to Produce a Non-Uniform Flow Distribution Across the Inlet Span of a Mixed Flow Turbine Rotor

2019 ◽  
Author(s):  
Richard Morrison ◽  
Stephen Spence ◽  
Sung In Kim ◽  
Thomas Leonard ◽  
Andre Starke
Keyword(s):  
Leading Edge ◽  
Operating Conditions ◽  
Operating Point ◽  
Mixed Flow ◽  
Flow Angle ◽  
Turbine Performance ◽  
Percentage Points ◽  
Wide Range ◽  
Turbine Rotors ◽  
Operating Points

Abstract Current trends in the automotive industry have placed an increased emphasis on downsized turbocharged engines for passenger vehicles. The turbocharger is increasingly relied upon to improve power output across a wide range of engine operating conditions, placing a greater emphasis on turbocharger offdesign performance. An off-design condition of significant importance is performance at low turbine velocity ratios, since it is relevant to engine transient response and also to efficient energy extraction from pressure pulses in the unsteady exhaust flow. An increased focus has been placed on equipping turbochargers with mixed flow turbine rotors instead of conventional radial flow turbine rotors to improve off-design performance and to reduce rotor inertia. A recognized feature of a mixed flow turbine is the spanwise variation of flow conditions across the blade leading edge. This is a consequence of the reduction in leading edge radius from shroud to hub, coupled with the increasing tangential velocity of the flow due to conserved angular momentum as the radius decreases. The result is increasingly positive incidence towards the hub side of the leading edge. The resulting region of highly positive incidence at the hub produces separation from the suction surface and generates significant loss within the rotor passage. The aim of this study was to determine if the losses in a MFT could be reduced by the use of leaned stator vanes, which deliberately created a significant spanwise variation of flow angle between hub and shroud at rotor inlet, to reduce the positive incidence at the hub. The turbine performance with a series of leaned vanes was compared against that of a straight vane using a validated CFD model. It was found that increasing vane lean improved turbine performance at all operating points considered. An increase of 3.2 percentage points in stage total-to-static efficiency was achieved at a key off-design operating point. Experimental testing of a set of leaned vanes and the baseline vanes confirmed the advantage of the leaned vanes at all operating points, with an increase in measured efficiency of 2.6 percentage points at the key off-design condition. Unsteady CFD models confirmed the same level of improvement at this operating point. The CFD and experimental results confirmed that the losses in a MFT can be reduced by the use of leaned stator vanes to shape the flow at rotor inlet.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

Long-term Effects of Triazol Growth Regulators on Stem Elongation of Rhododendron and Kalmia

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 436E-436
Author(s):  
Martin P.N. Gent
Keyword(s):  
Dose Response ◽  
Growth Regulator ◽  
Stem Elongation ◽  
Spray Application ◽  
Long Term Effects ◽  
Potted Plants ◽  
Response Coefficient ◽  
Wide Range ◽  
Second Year

The persistence of effects of paclobutrazol or uniconazol on stem elongation was determined for several years after large-leaf Rhododendron and Kalmia latifolia were treated with a single-spray application of these triazol growth-regulator chemicals. Potted plants were treated in the second year from propagation, and transplanted into the field in the following spring. The elongation of stems was measured in the year of application and in the following 2 to 4 years. Treatments with a wide range of doses were applied in 1991, 1992, or 1995. For all except the most-dilute applications, stem elongation was retarded in the year following application. At the highest doses, stem growth was inhibited 2 years following application. The results could be explained by a model of growth regulator action that assumed stem elongation was inversely related to amount of growth regulator applied. The dose response coefficient for paclobutrazol was less than that for uniconazol. The dose that inhibited stem elongation one-half as much as a saturating dose was about 0.5 and 0.05 mg/plant, for paclobutrazol and uniconazol, respectively. The dose response coefficient decreased exponentially with time after application, with an exponential time constant of about 2/year. The model predicted a dose of growth regulator that inhibited 0.9 of stem elongation immediately after application would continue to inhibit 0.5 of stem elongation in the following year.

Nitrogen Removal from Anaerobically-Treated Leachate

1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis
Keyword(s):  
Nitrogen Removal ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Anaerobic Filter ◽  
Ph Values ◽  
Wide Range ◽  
Ammonia Desorption ◽  
Effects Of Ph

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.

scholarly journals Applications of Biocatalysts for Sustainable Oxidation of Phenolic Pollutants: A Review

2021 ◽  
Vol 13 (15) ◽  
pp. 8620
Author(s):  
Sanaz Salehi ◽  
Kourosh Abdollahi ◽  
Reza Panahi ◽  
Nejat Rahmanian ◽  
Mozaffar Shakeri ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Operating Conditions ◽  
Phenolic Pollutants ◽  
Petroleum Refinery Wastewater ◽  
Start Up ◽  
Low Concentrations ◽  
Effective Removal ◽  
Wide Range ◽  
Loading Effects ◽  
Spent Caustic

Phenol and its derivatives are hazardous, teratogenic and mutagenic, and have gained significant attention in recent years due to their high toxicity even at low concentrations. Phenolic compounds appear in petroleum refinery wastewater from several sources, such as the neutralized spent caustic waste streams, the tank water drain, the desalter effluent and the production unit. Therefore, effective treatments of such wastewaters are crucial. Conventional techniques used to treat these wastewaters pose several drawbacks, such as incomplete or low efficient removal of phenols. Recently, biocatalysts have attracted much attention for the sustainable and effective removal of toxic chemicals like phenols from wastewaters. The advantages of biocatalytic processes over the conventional treatment methods are their ability to operate over a wide range of operating conditions, low consumption of oxidants, simpler process control, and no delays or shock loading effects associated with the start-up/shutdown of the plant. Among different biocatalysts, oxidoreductases (i.e., tyrosinase, laccase and horseradish peroxidase) are known as green catalysts with massive potentialities to sustainably tackle phenolic contaminants of high concerns. Such enzymes mainly catalyze the o-hydroxylation of a broad spectrum of environmentally related contaminants into their corresponding o-diphenols. This review covers the latest advancement regarding the exploitation of these enzymes for sustainable oxidation of phenolic compounds in wastewater, and suggests a way forward.

scholarly journals Wide range continuously tunable and fast thermal switching based on compressible graphene composite foams

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tingting Du ◽  
Zixin Xiong ◽  
Luis Delgado ◽  
Weizhi Liao ◽  
Joseph Peoples ◽  
...  
Keyword(s):  
Thermal Management ◽  
Dynamic Control ◽  
Operating Conditions ◽  
Dynamic Thermal Management ◽  
Graphene Composite ◽  
Continuous Tuning ◽  
Composite Foams ◽  
Wide Range ◽  
Thermal Switches ◽  
Thermal Switching

AbstractThermal switches have gained intense interest recently for enabling dynamic thermal management of electronic devices and batteries that need to function at dramatically varied ambient or operating conditions. However, current approaches have limitations such as the lack of continuous tunability, low switching ratio, low speed, and not being scalable. Here, a continuously tunable, wide-range, and fast thermal switching approach is proposed and demonstrated using compressible graphene composite foams. Large (~8x) continuous tuning of the thermal resistance is achieved from the uncompressed to the fully compressed state. Environmental chamber experiments show that our variable thermal resistor can precisely stabilize the operating temperature of a heat generating device while the ambient temperature varies continuously by ~10 °C or the heat generation rate varies by a factor of 2.7. This thermal device is promising for dynamic control of operating temperatures in battery thermal management, space conditioning, vehicle thermal comfort, and thermal energy storage.

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