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Christopher D Wilson - One of the best experts on this subject based on the ideXlab platform.
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do silent ships see more fish comparison of a noise reduced and a Conventional Research vessel in alaska
Advances in Experimental Medicine and Biology, 2012Co-Authors: Alex De Robertis, Christopher D Wilson, Neal J WilliamsonAbstract:Under some circumstances, fish detect and avoid approaching vessels, often well before the vessel passes over the fish (Mitson 1995). Such vessel-induced avoidance behavior is potentially a major source of error in surveys of fish populations. Sound propagates a long distance in water compared with other stimuli, and fish are generally most sensitive to sound in the frequency range at which the underwater-radiated noise from ships is most intense (Mann et al. 2009). Thus the primary stimulus for this avoidance behavior is thought to be auditory (Mitson 1995). The concern that vessel noise causes fish avoidance has led to the formulation of recommendations for maximum low-frequency (<1-kHz) underwater-radiated noise levels for fisheries Research vessels (Mitson 1995). These recommendations, made under the auspices of the International Council for the Exploration of the Seas (ICES), are based on the hearing capabilities of Clupea harengus (Atlantic herring) and Gadus morhua (Atlantic cod), two species with sensitive hearing; the recommendation is therefore expected to minimize noise-induced vessel avoidance for other species as well.
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silent ships do not always encounter more fish revisited comparison of acoustic backscatter from walleye pollock recorded by a noise reduced and a Conventional Research vessel in the eastern bering sea
Ices Journal of Marine Science, 2011Co-Authors: Alex De Robertis, Christopher D WilsonAbstract:Vessel-induced avoidance behaviour is potentially a major source of error in surveys of fish populations. Noise-reduced Research vessels have been constructed in an effort to minimize fish reactions to auditory stimuli produced by survey vessels. Here, measurements of acoustic backscatter from walleye pollock (Theragra chalcogramma) made on the eastern Bering Sea Shelf from the Conventional NOAA ship “Miller Freeman” (MF) are compared with similar measurements made on the noise-reduced NOAA ship “Oscar Dyson” (OD). As in a previous study, acoustic abundance measurements from these vessels were equivalent during daylight, when large-scale acoustic surveying is conducted. However, significant differences were observed at night: on average, 44% more pollock backscatter was observed from OD than MF. Observations with a free-drifting echosounder buoy suggest that the night-time discrepancy is attributable to a stronger behavioural response to the passage of the louder MF, and a resulting decrease in pollock target strength. Pollock did not exhibit a strong reaction to the passage of OD. These observations are consistent with previous comparisons of these vessels, which show that with vessel differences, the noise-reduced OD detects more pollock.
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silent ships do not always encounter more fish comparison of acoustic backscatter recorded by a noise reduced and a Conventional Research vessel
Ices Journal of Marine Science, 2008Co-Authors: Alex De Robertis, Neal J Williamson, Vidar Hjellvik, Christopher D WilsonAbstract:The extent to which fish avoid approaching Research vessels is an important source of uncertainty in fisheries surveys. Vessels radiate noise at the frequencies where fish hearing is most sensitive, and noise is thus thought to be the primary stimulus for vessel avoidance. In an effort to minimize vessel avoidance, international standards for noise emission by Research vessels have been established. Although vessels meeting these criteria are now in service, the effectiveness of noise quietening on vessel avoidance remains poorly understood. The new, noise-reduced, RV “Oscar Dyson” (OD) will augment the Conventionally constructed Research vessel, “Miller Freeman” (MF) and serve as the primary platform in conducting acoustic surveys of walleye pollock (Theragra chalcogramma) in Alaska. To investigate whether noise-reduction measures result in differential avoidance, which would bias the pollock abundance time-series, we conducted an inter-vessel comparison of acoustic backscatter recorded by OD and MF during a survey of walleye pollock in 2006 in the eastern Bering Sea. Overall, we found no evidence for differences in vessel avoidance that would impact the echo integration results of adult pollock. Analysis of pollock depth distributions from both vessels suggests that there is a comparatively greater diving response to OD, with the reaction taking place primarily after the vessel has passed and for fish shallower than 90 m. Given that the change in vertical distribution is after the fish have been detected by the echosounder, this reaction should not influence echo-integration measurements. The results indicate that use of the OD rather than the MF is unlikely to bias the Bering Sea survey time-series through changes in vessel avoidance by adult walleye pollock.
Alex De Robertis - One of the best experts on this subject based on the ideXlab platform.
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do silent ships see more fish comparison of a noise reduced and a Conventional Research vessel in alaska
Advances in Experimental Medicine and Biology, 2012Co-Authors: Alex De Robertis, Christopher D Wilson, Neal J WilliamsonAbstract:Under some circumstances, fish detect and avoid approaching vessels, often well before the vessel passes over the fish (Mitson 1995). Such vessel-induced avoidance behavior is potentially a major source of error in surveys of fish populations. Sound propagates a long distance in water compared with other stimuli, and fish are generally most sensitive to sound in the frequency range at which the underwater-radiated noise from ships is most intense (Mann et al. 2009). Thus the primary stimulus for this avoidance behavior is thought to be auditory (Mitson 1995). The concern that vessel noise causes fish avoidance has led to the formulation of recommendations for maximum low-frequency (<1-kHz) underwater-radiated noise levels for fisheries Research vessels (Mitson 1995). These recommendations, made under the auspices of the International Council for the Exploration of the Seas (ICES), are based on the hearing capabilities of Clupea harengus (Atlantic herring) and Gadus morhua (Atlantic cod), two species with sensitive hearing; the recommendation is therefore expected to minimize noise-induced vessel avoidance for other species as well.
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silent ships do not always encounter more fish revisited comparison of acoustic backscatter from walleye pollock recorded by a noise reduced and a Conventional Research vessel in the eastern bering sea
Ices Journal of Marine Science, 2011Co-Authors: Alex De Robertis, Christopher D WilsonAbstract:Vessel-induced avoidance behaviour is potentially a major source of error in surveys of fish populations. Noise-reduced Research vessels have been constructed in an effort to minimize fish reactions to auditory stimuli produced by survey vessels. Here, measurements of acoustic backscatter from walleye pollock (Theragra chalcogramma) made on the eastern Bering Sea Shelf from the Conventional NOAA ship “Miller Freeman” (MF) are compared with similar measurements made on the noise-reduced NOAA ship “Oscar Dyson” (OD). As in a previous study, acoustic abundance measurements from these vessels were equivalent during daylight, when large-scale acoustic surveying is conducted. However, significant differences were observed at night: on average, 44% more pollock backscatter was observed from OD than MF. Observations with a free-drifting echosounder buoy suggest that the night-time discrepancy is attributable to a stronger behavioural response to the passage of the louder MF, and a resulting decrease in pollock target strength. Pollock did not exhibit a strong reaction to the passage of OD. These observations are consistent with previous comparisons of these vessels, which show that with vessel differences, the noise-reduced OD detects more pollock.
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silent ships do not always encounter more fish comparison of acoustic backscatter recorded by a noise reduced and a Conventional Research vessel
Ices Journal of Marine Science, 2008Co-Authors: Alex De Robertis, Neal J Williamson, Vidar Hjellvik, Christopher D WilsonAbstract:The extent to which fish avoid approaching Research vessels is an important source of uncertainty in fisheries surveys. Vessels radiate noise at the frequencies where fish hearing is most sensitive, and noise is thus thought to be the primary stimulus for vessel avoidance. In an effort to minimize vessel avoidance, international standards for noise emission by Research vessels have been established. Although vessels meeting these criteria are now in service, the effectiveness of noise quietening on vessel avoidance remains poorly understood. The new, noise-reduced, RV “Oscar Dyson” (OD) will augment the Conventionally constructed Research vessel, “Miller Freeman” (MF) and serve as the primary platform in conducting acoustic surveys of walleye pollock (Theragra chalcogramma) in Alaska. To investigate whether noise-reduction measures result in differential avoidance, which would bias the pollock abundance time-series, we conducted an inter-vessel comparison of acoustic backscatter recorded by OD and MF during a survey of walleye pollock in 2006 in the eastern Bering Sea. Overall, we found no evidence for differences in vessel avoidance that would impact the echo integration results of adult pollock. Analysis of pollock depth distributions from both vessels suggests that there is a comparatively greater diving response to OD, with the reaction taking place primarily after the vessel has passed and for fish shallower than 90 m. Given that the change in vertical distribution is after the fish have been detected by the echosounder, this reaction should not influence echo-integration measurements. The results indicate that use of the OD rather than the MF is unlikely to bias the Bering Sea survey time-series through changes in vessel avoidance by adult walleye pollock.
M J Witte - One of the best experts on this subject based on the ideXlab platform.
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Conventional Research house variable speed electric heat pump heating characterization test results topical report september 1989 january 1990
1991Co-Authors: N P Leslie, R L Hedrick, R H Henninger, M J WitteAbstract:Heating characterization tests were conducted at GRI's Conventional Research House in Chicago, Illinois. A high efficiency electric heat pump with variable speed condensing unit and variable speed indoor fan was used as the heating system. The nominal heating capacity was 34,600 Btu/h at high speed and 47F outdoor air temperature. The baseline operating strategy was continuous heating with a central thermostat setpoint of 72F. The Research house was moderately furnished to approximate conditions of occupancy for a family of three. Occupancy and appliance simulation protocols were implemented in accordance with GRI's Research House Utilization Plan throughout the test period. A data acquisition system monitored 148 data channels on a minute by minute and hourly basis to characterize comfort, energy consumption and dynamic response of the variable speed system. The heat pump maintained good comfort conditions throughout the winter on the first floor, with cooler conditions in the basement due to ground effects. The system coefficient of performance was over 4.0 at the lowest speed operation and approached 1.0 at the highest speed including resistance heat. Estimated seasonal energy consumption was 9,692 kWh based on TMY data.
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Conventional Research house variable speed electric heat pump cooling characterization test results topical report july september 1989
1991Co-Authors: N P Leslie, R L Hedrick, M J WitteAbstract:Cooling characterization tests were conducted at GRI's Conventional Research House in Chicago, Illinois. A high efficiency electric heat pump with variable speed condensing unit and variable speed indoor fan was used as the cooling system. The low speed capacity was 12,000 Btu/h and the high speed capacity was 37,600 Btu/h. The baseline operating strategy was continuous cooling with a central thermostat setpoint of 77 deg F. The Research house was moderately furnished to approximate conditions of occupancy for a family of three. Occupancy and appliance simulation protocols were implemented in accordance with GRI's Research House Utilization Plan throughout the test period. A data acquisition system monitored 148 data channels on a minute by minute and hourly basis to characterize comfort, energy consumption and dynamic response of the variable speed system. The heat pump maintained good comfort conditions throughout the summer on the first floor, with cooler conditions in the basement due to ground effects. The system energy efficiency ratio was over 20 at the lowest speed operation and 9.3 at the highest speed. Seasonal energy consumption was 1,472 kWh based on TMY data.
Neal J Williamson - One of the best experts on this subject based on the ideXlab platform.
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do silent ships see more fish comparison of a noise reduced and a Conventional Research vessel in alaska
Advances in Experimental Medicine and Biology, 2012Co-Authors: Alex De Robertis, Christopher D Wilson, Neal J WilliamsonAbstract:Under some circumstances, fish detect and avoid approaching vessels, often well before the vessel passes over the fish (Mitson 1995). Such vessel-induced avoidance behavior is potentially a major source of error in surveys of fish populations. Sound propagates a long distance in water compared with other stimuli, and fish are generally most sensitive to sound in the frequency range at which the underwater-radiated noise from ships is most intense (Mann et al. 2009). Thus the primary stimulus for this avoidance behavior is thought to be auditory (Mitson 1995). The concern that vessel noise causes fish avoidance has led to the formulation of recommendations for maximum low-frequency (<1-kHz) underwater-radiated noise levels for fisheries Research vessels (Mitson 1995). These recommendations, made under the auspices of the International Council for the Exploration of the Seas (ICES), are based on the hearing capabilities of Clupea harengus (Atlantic herring) and Gadus morhua (Atlantic cod), two species with sensitive hearing; the recommendation is therefore expected to minimize noise-induced vessel avoidance for other species as well.
-
silent ships do not always encounter more fish comparison of acoustic backscatter recorded by a noise reduced and a Conventional Research vessel
Ices Journal of Marine Science, 2008Co-Authors: Alex De Robertis, Neal J Williamson, Vidar Hjellvik, Christopher D WilsonAbstract:The extent to which fish avoid approaching Research vessels is an important source of uncertainty in fisheries surveys. Vessels radiate noise at the frequencies where fish hearing is most sensitive, and noise is thus thought to be the primary stimulus for vessel avoidance. In an effort to minimize vessel avoidance, international standards for noise emission by Research vessels have been established. Although vessels meeting these criteria are now in service, the effectiveness of noise quietening on vessel avoidance remains poorly understood. The new, noise-reduced, RV “Oscar Dyson” (OD) will augment the Conventionally constructed Research vessel, “Miller Freeman” (MF) and serve as the primary platform in conducting acoustic surveys of walleye pollock (Theragra chalcogramma) in Alaska. To investigate whether noise-reduction measures result in differential avoidance, which would bias the pollock abundance time-series, we conducted an inter-vessel comparison of acoustic backscatter recorded by OD and MF during a survey of walleye pollock in 2006 in the eastern Bering Sea. Overall, we found no evidence for differences in vessel avoidance that would impact the echo integration results of adult pollock. Analysis of pollock depth distributions from both vessels suggests that there is a comparatively greater diving response to OD, with the reaction taking place primarily after the vessel has passed and for fish shallower than 90 m. Given that the change in vertical distribution is after the fish have been detected by the echosounder, this reaction should not influence echo-integration measurements. The results indicate that use of the OD rather than the MF is unlikely to bias the Bering Sea survey time-series through changes in vessel avoidance by adult walleye pollock.
R L Hedrick - One of the best experts on this subject based on the ideXlab platform.
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Conventional Research house measurements of emissions from unvented gas space heaters topical report april may 1991
1995Co-Authors: R L Hedrick, E K KrugAbstract:Experiments were conducted with four unvented gas space heaters at the GRI Conventional Research House in Chicago, Illinois. Each of the space heaters used distinctly different designs: (1) blue-flame convective heater-blue flame with free convection out the top of the heater; (2) radiant-tile heater-heats ceramic tiles which transmit infrared radiation; (3) perforated-tube convective heater-utilizes a long perforated tube to provide an extended combustion zone; (4) fan-forced convective heater-blue flame convective heater with a fan to improve combustion characteristics. Two experiment types were conducted. Heater experiments consisted of operating the heaters continuously for eight hours in the living room, followed by a 15 hour decay period. Pilot light only experiments were also conducted. Concentrations of NO2, NO, CO, CO2, and total hydrocarbons were monitored in six locations, five indoors plus outdoors.
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nitrogen dioxide measurement method characterization at the gri Conventional Research house topical report august september 1989
1994Co-Authors: R L Hedrick, F Rasouli, E K Krug, G PudloAbstract:Experiments were conducted to measure NO2 concentrations using three types of instruments: (1) Chemiluminescent NO/NOx analyzer (EPA reference method), (2) Chemiluminiscent NO2 analyzer using luminol solution, and (3) Electrochemical NO2 analyzer. The electrochemical and luminol analyzers were evaluated in terms of their linearity, bias and correlation relative to the chemiluminescent analyzer, and interference by nitric oxide (NO) and nitrous acid (HONO). The chemiluminescent analyzer measured concentrations in samples that included some that were passed through an acid denuder to remove HONO. The electrochemical analyzers were small and portable, but were not as accurate and precise as the other types. The luminol based analyzers had good accuracy at concentrations below about 120 ppb. The luminol analyzer was not sensitive to HONO.
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Conventional Research house variable speed electric heat pump heating characterization test results topical report september 1989 january 1990
1991Co-Authors: N P Leslie, R L Hedrick, R H Henninger, M J WitteAbstract:Heating characterization tests were conducted at GRI's Conventional Research House in Chicago, Illinois. A high efficiency electric heat pump with variable speed condensing unit and variable speed indoor fan was used as the heating system. The nominal heating capacity was 34,600 Btu/h at high speed and 47F outdoor air temperature. The baseline operating strategy was continuous heating with a central thermostat setpoint of 72F. The Research house was moderately furnished to approximate conditions of occupancy for a family of three. Occupancy and appliance simulation protocols were implemented in accordance with GRI's Research House Utilization Plan throughout the test period. A data acquisition system monitored 148 data channels on a minute by minute and hourly basis to characterize comfort, energy consumption and dynamic response of the variable speed system. The heat pump maintained good comfort conditions throughout the winter on the first floor, with cooler conditions in the basement due to ground effects. The system coefficient of performance was over 4.0 at the lowest speed operation and approached 1.0 at the highest speed including resistance heat. Estimated seasonal energy consumption was 9,692 kWh based on TMY data.
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Conventional Research house variable speed electric heat pump cooling characterization test results topical report july september 1989
1991Co-Authors: N P Leslie, R L Hedrick, M J WitteAbstract:Cooling characterization tests were conducted at GRI's Conventional Research House in Chicago, Illinois. A high efficiency electric heat pump with variable speed condensing unit and variable speed indoor fan was used as the cooling system. The low speed capacity was 12,000 Btu/h and the high speed capacity was 37,600 Btu/h. The baseline operating strategy was continuous cooling with a central thermostat setpoint of 77 deg F. The Research house was moderately furnished to approximate conditions of occupancy for a family of three. Occupancy and appliance simulation protocols were implemented in accordance with GRI's Research House Utilization Plan throughout the test period. A data acquisition system monitored 148 data channels on a minute by minute and hourly basis to characterize comfort, energy consumption and dynamic response of the variable speed system. The heat pump maintained good comfort conditions throughout the summer on the first floor, with cooler conditions in the basement due to ground effects. The system energy efficiency ratio was over 20 at the lowest speed operation and 9.3 at the highest speed. Seasonal energy consumption was 1,472 kWh based on TMY data.