scholarly journals Application of parametric speakers to radio acoustic sounding system

2019 ◽  
Vol 12 (10) ◽  
pp. 5699-5715 ◽  
Author(s):  
Ahoro Adachi ◽  
Hiroyuki Hashiguchi
Keyword(s):  
Standard Deviation ◽  
Temperature Difference ◽  
Acoustic Waves ◽  
Urban Areas ◽  
Vertical Profile ◽  
Wind Profiler ◽  
Acoustic Beam ◽  
Acoustic Sounding ◽  
Accuracy And Precision ◽  
Virtual Temperature

Abstract. In this study, a wind profiler with a radio acoustic sounding system (RASS) and operational radiosonde measurements were used to investigate the technical practicability and reliability of using parametric speakers to measure the vertical profile of virtual temperature. Characteristics of parametric speakers include high directivity and very low side lobes, which are preferable for RASS, especially those operating in urban areas. The experiments were conducted on fine days with light winds to mitigate the effects of the horizontal and vertical components of wind on acoustic waves used for RASS. The results of this study indicated that, although parametric speaker RASS is susceptible to horizontal winds due to the narrower acoustic beam, bias and standard deviation of parametric speaker RASS versus radiosonde virtual temperature difference (0.1 ∘C, 0.4 ∘C) were close to those from acoustic speakers (0.0 ∘C, 0.4 ∘C). In addition, when compared with acoustic speaker RASS, the values for the parametric speaker RASS were even smaller (0.1 ∘C, 0.2 ∘C). Based on these results, it is concluded that the parametric speaker RASS has accuracy and precision comparable with acoustic speaker RASS despite its high directivity of sound.

scholarly journals Application of Parametric Speakers to Radio Acoustic Sounding System

2019 ◽  
Author(s):  
Ahoro Adachi ◽  
Hiroyuki Hashiguchi
Keyword(s):  
Standard Deviation ◽  
Temperature Difference ◽  
Acoustic Waves ◽  
Urban Areas ◽  
Vertical Profile ◽  
Wind Profiler ◽  
Acoustic Beam ◽  
Acoustic Sounding ◽  
Accuracy And Precision ◽  
Virtual Temperature

Abstract. In this study, a wind profiler with radio acoustic sounding system (RASS) and operational radiosonde measurements were used to investigate the technical practicability and reliability of using parametric speakers to measure the vertical profile of virtual temperature. Characteristics of parametric speakers include high directivity and very low sidelobes, which are preferable for RASS, especially those operating at urban areas, if this type of speaker exhibits reliability comparable with acoustic speakers for RASS measurements. The experiments were conducted on fine days with light winds to mitigate the effects of the horizontal and vertical components of wind on acoustic waves used for RASS. The results of this study indicated that, although parametric speaker RASS is susceptible to horizontal winds due to the narrower acoustic beam, bias and standard deviation of parametric speaker RASS/radiosonde virtual temperature difference (0.1 °C, 0.4 °C) were close to that from acoustic speakers (0.0 °C, 0.4 °C). In addition, when compared with acoustic speaker RASS, the values for the parametric speaker RASS were even smaller (0.1 °C, 0.2 °C). Based on these results, it is concluded that the parametric speaker RASS has accuracy and precision comparable with acoustic speaker RASS despite its high directivity of sound.

scholarly journals Preliminary observation of temperature profiles by radio acoustic sounding system (RASS) with a 1280 MHz lower atmospheric wind profiler at Gadanki, India

2012 ◽  
Vol 5 (3) ◽  
pp. 4447-4472 ◽  
Author(s):  
T. V. Chandrasekhar Sarma ◽  
P. Srinivasulu ◽  
T. Tsuda
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Atmospheric Temperature ◽  
Precipitation Event ◽  
Wind Profiler ◽  
Acoustic Sounding ◽  
Pulse Transmission ◽  
Mst Radar ◽  
Uhf Wind Profiler ◽  
Virtual Temperature

Abstract. A UHF wind profiler operating at 1280 MHz has been developed at NARL for atmospheric studies in the planetary boundary layer. In order to explore application of radio acoustic sounding system (RASS) technique to this profiler, a suitable acoustic attachment was designed and preliminary experiments were conducted on 27–30 August 2010. Height profiles of virtual temperature, Tv, in the planetary boundary layer were derived with 1 μs and 0.25 μs pulse transmission, corresponding to a height resolution of 150 m and about 40 m, respectively. Diurnal variation of Tv is clearly recognized, and perturbations of Tv are also seen in association with a precipitation event. Simultaneous profiles obtained from the MST Radar-RASS and an onsite 50 m tower demonstrate the capability to continuously profile the atmospheric temperature from near the ground to upper tropospheric altitudes.

scholarly journals Experimental demonstration of negative refraction with 3D locally resonant acoustic metafluids

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benoit Tallon ◽  
Artem Kovalenko ◽  
Olivier Poncelet ◽  
Christophe Aristégui ◽  
Olivier Mondain-Monval ◽  
...  
Keyword(s):  
Experimental Data ◽  
Yield Stress ◽  
Multiple Scattering ◽  
Silicone Rubber ◽  
Acoustic Waves ◽  
Scattering Theory ◽  
Negative Refraction ◽  
Volume Fraction ◽  
Experimental Demonstration ◽  
Acoustic Beam

AbstractNegative refraction of acoustic waves is demonstrated through underwater experiments conducted at ultrasonic frequencies on a 3D locally resonant acoustic metafluid made of soft porous silicone-rubber micro-beads suspended in a yield-stress fluid. By measuring the refracted angle of the acoustic beam transmitted through this metafluid shaped as a prism, we determine the acoustic index to water according to Snell’s law. These experimental data are then compared with an excellent agreement to calculations performed in the framework of Multiple Scattering Theory showing that the emergence of negative refraction depends on the volume fraction $$\Phi$$ Φ of the resonant micro-beads. For diluted metafluid ($$\Phi =3\%$$ Φ = 3 % ), only positive refraction occurs whereas negative refraction is demonstrated over a broad frequency band with concentrated metafluid ($$\Phi =17\%$$ Φ = 17 % ).

scholarly journals HEAVY SMOKING

2012 ◽  
Vol 19 (04) ◽  
pp. 433-435
Author(s):  
MUMTAZ ALI SHAIKH ◽  
DUR-E- YAKTA ◽  
DARGAHI SHAIKH
Keyword(s):  
Standard Deviation ◽  
Urban Areas ◽  
Sampling Technique ◽  
Serum Lipoprotein ◽  
High Density Lipoproteins ◽  
Lipid Levels ◽  
Serum Triglycerides ◽  
Heavy Smoking ◽  
Female Ratio ◽  
Heavy Smokers

Objective: This study is conducted to observe the serum lipoprotein alterations in chronic heavy smokers in LUMHS Sindh. Study Design: Analytical study Material and Methods: It was conducted on 60 non obese adult smokers, both sexes, who smoked more than twenty cigarettes or beeries a day regularly for more than five years. All the participants were current smokers. Sampling technique was simple random technique. Setting: The study was conducted in outdoor department of LUMHS Jamshoro/Hyderabad. Period: Jan 2010 to Jan 2011. Eighteen hours fasting blood sample was sent for lipid studies. Lipids studied were serum cholesterol, serum triglycerides, high density lipoproteins and low density lipoproteins. For control values ATP 3 guidelines were used. Statistics: Mean of statistical values was calculated with standard deviation and variance in standard deviation. Results obtained were analyzed by SPSS 11. Results: Age of the patients was 25-70 years. Mean age was 47.81±12.96 years. Median age was 50 years. Male/ female ratio was 45/15. Patients were from both rural and urban areas. Mean duration of smoking was 25.5±9.15 years. The study carried out on 60 chronic heavy smokers, showed deranged lipid levels as: Total cholesterol mean 237.57 mg/dl ±37.89; TG mean 203.76 mg/dl ±47.08; LDL-C mean 158.62 mg/dl ±17.25; HDL-C mean 29.67 mg/dl ±3.12. Results are shown in Table No I. Conclusions: Our study concluded at LUMHS showed that by continuous heavy smoking the serum lipid levels get deranged.

scholarly journals Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications

2016 ◽  
Author(s):  
Laura Bianco ◽  
Katja Friedrich ◽  
James Wilczak ◽  
Duane Hazen ◽  
Daniel Wolfe ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Relative Humidity ◽  
Mean Absolute Error ◽  
Microwave Radiometer ◽  
Absolute Error ◽  
Acoustic Sounding ◽  
Energy Applications ◽  
Virtual Temperature ◽  
Microwave Radiometers

Abstract. To assess current remote-sensing capabilities for wind energy applications, a remote-sensing system evaluation study, called XPIA (eXperimental Planetary boundary layer Instrument Assessment), was held in the spring of 2015 at NOAA’s Boulder Atmospheric Observatory (BAO) facility. Several remote-sensing platforms were evaluated to determine their suitability for the verification and validation processes used to test the accuracy of numerical weather prediction models. The evaluation of these platforms was performed with respect to well-defined reference systems: the BAO’s 300-m tower equipped at 6 levels (50, 100, 150, 200, 250, and 300 m) with 12 sonic anemometers and 6 temperature and relative humidity sensors; and approximately 60 radiosonde launches. In this study we first employ these reference measurements to validate temperature profiles retrieved by two co-located microwave radiometers, as well as virtual temperature measured by co-located wind profiling radars equipped with radio acoustic sounding systems. Results indicate a mean absolute error in the temperature retrieved by the microwave radiometers below 1.5 °C in the lowest 5 km of the atmosphere, and a mean absolute error in the virtual temperature measured by the radio acoustic sounding systems below 0.8 °C in the layer of the atmosphere covered by these measurements (up to approximately 1.6–2 km). We also investigated the benefit of the vertical velocity applied to the speed of sound before computing the virtual temperature by the radio acoustic sounding systems. We find that using this correction frequently increases the RASS error, and that it should not be routinely applied to all data. Water vapor density profiles measured by the MWRs were also compared with similar measurements from the soundings, showing the capability of MWRs to follow the vertical profile measured by the sounding, and finding a mean absolute error below 0.5 g m−3 in the lowest 5 km of the atmosphere. However, the relative humidity profiles measured by the microwave radiometer lack the high-resolution details available from radiosonde profiles. An encouraging and significant finding of this study was that the coefficient of determination between the lapse rate measured by the microwave radiometer and the tower measurements over the tower levels between 50 and 300 m ranged from 0.76 to 0.91, proving that these remote-sensing instruments can provide accurate information on atmospheric stability conditions in the lower boundary layer.

An Adaptive Statistically Based Controller for Through-Feed Centerless Grinding

2000 ◽  
Vol 123 (3) ◽  
pp. 380-386 ◽  
Author(s):  
Richard W. Cowan ◽  
Daniel J. Schertz ◽  
Thomas R. Kurfess
Keyword(s):  
Standard Deviation ◽  
Statistical Approach ◽  
High Volume ◽  
Manufacturing Processes ◽  
Control Methods ◽  
Statistical Control ◽  
Accuracy And Precision ◽  
Self Tuning ◽  
Centerless Grinding ◽  
The Mean

The purpose of this research is to develop a statistically based controller that is “self-tuning.” High volume manufacturing processes such as through-feed centerless grinding are best controlled with a statistical approach, but traditional methods of statistical control generally rely on fixed parameters that must be determined. These values must be precisely known and the true physical characteristics they model must remain constant throughout grinding, or traditional statistical control methods may break down. The mean and standard deviation of a process are measures of its accuracy and precision. The scheme developed here makes control decisions based on the real-time values of these quantities. This self-adjusting ability can compensate for changes in machine parameters as they occur.

scholarly journals A high-resolution and observationally constrained OMI NO<sub>2</sub> satellite retrieval

2017 ◽  
Author(s):  
Daniel L. Goldberg ◽  
Lok N. Lamsal ◽  
Christopher P. Loughner ◽  
Zifeng Lu ◽  
David G. Streets
Keyword(s):  
United States ◽  
High Resolution ◽  
Urban Areas ◽  
Vertical Profile ◽  
Model Simulation ◽  
New Product ◽  
Eastern United States ◽  
Shape Factors ◽  
Air Mass ◽  
Tropospheric No2

Abstract. This work presents a new high resolution NO2 dataset derived from the standard NASA Ozone Monitoring Instrument (OMI) NO2 version 3.0 retrieval that can be used to estimate surface level concentrations. The standard NASA product uses NO2 vertical profile shape factors from a 1.25° × 1° (~ 110 × 110 km) resolution Global Model Initiative (GMI) model simulation to calculate air mass factors, a critical value used to determine observed tropospheric NO2 vertical columns. To better estimate vertical profile shape factors, we use a high resolution Community Multi-scale Air Quality (CMAQ) model simulation (1.33 × 1.33 km) to generate tropospheric air mass factors and tropospheric NO2 columns during summertime in the eastern United States. Results show OMI NO2 tropospheric columns in this new product increase by up to 160 % in city centers, and decrease by 20–50 % in the rural areas outside of urban areas when compared to the operational product. This new product shows much better agreement with the Pandora NO2 spectrometer measurements acquired during the DISCOVER-AQ Maryland field campaign. Furthermore, the correlation between this satellite product and EPA NO2 monitors in urban areas has improved dramatically: r2 = 0.60 in new product, r2 = 0.39 in operational product, signifying that this new product is a better indicator of surface concentrations than the operational product. Our work emphasizes the need to use high resolution models to re-calculate satellite data in areas with large spatial heterogeneities in NOx emissions. Although the current work is focused on the eastern United States, the methodology developed in this work can be applied to other world regions to produce high-quality region-specific NO2 satellite retrievals.

Combined Determination of Phosphorus and Arsenic in Molybdenum Concentrate by Molybdenum Blue Spectrophotometric Method

2014 ◽  
Vol 1033-1034 ◽  
pp. 521-525
Author(s):  
Cheng Ying Zhou ◽  
Wei Qu ◽  
Liu Lu Cai
Keyword(s):  
Standard Deviation ◽  
Good Accuracy ◽  
Standard Addition ◽  
Additive Property ◽  
Molybdenum Blue ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Molybdenum Concentrate ◽  
Total Absorbance

This paper determined the total absorbance of phosphorus molybdenum blue and arsenic molybdenum blue by using the additive property of their absorbance values. By eliminating the interference of arsenic by reduction masking with composite reducing agent Na2SO3-Na2S2O3-KBr, the absorbance of phosphorus could be obtained. Thus, the content of phosphorus and arsenic could be calculated, respectively. The results show that the work curves of this method for phosphorus and arsenic are consistent with Beer’s law when the content of phosphorus and arsenic is 0-0.60ug/mL and 0-2.00ug/mL, respectively. The standard addition recovery rate of phosphorus and arsenic is 98.80%-101.04% and 99.00%-101.50%, respectively. The relative standard deviation of phosphorus and arsenic is less than 4.0% with good accuracy and precision. This method is simple and fast to determine phosphorus and arsenic in molybdenum concentrate, and the results are accurate and reliable.

scholarly journals A DECADAL ANALYSIS AND SENSITIVITY STUDY USING MOPITT CO COLUMNS OVER ASIA

2018 ◽  
Vol XLII-3/W5 ◽  
pp. 53-59 ◽  
Author(s):  
C. Lin ◽  
J. Cohen
Keyword(s):  
Standard Deviation ◽  
Biomass Burning ◽  
Urban Areas ◽  
Sensitivity Study ◽  
The Other ◽  
Peak Time ◽  
Urban Regions ◽  
Forest Clearing ◽  
Other Hand ◽  
A New Technique

<p><strong>Abstract.</strong> Biomass burning and urbanization are both significant sources of CO emissions and atmospheric loadings in the real environment. The sources of CO are due to incomplete combustion, on one hand of biomass from agriculture or forest clearing, and on the other hand from coal, oil, gas, and other similar materials. However, the spatial and temporal underlying properties and patterns are quite different between these two types of source regions, with urban regions having a relatively constant source of CO emissions, with only short term concentration fluctuations due to local meteorology. On the other hand, in biomass burning regions, the emissions themselves tend to be highly concentrated over a short burning period, and very low otherwise. We hence present a new technique to classify and quantify biomass burning regions and urban regions based on an objective analysis of the CO total column measurements from the MOPITT satellite. By using all of the data from 2000&amp;ndash;2016, in connection with averages and standard deviation cutoffs, we successfully determine these regions. By performing a sensitivity analysis, in connection with additional ground-based measurements, we determine that the ideal cutoffs for the mean column loading and standard deviation of the column loading 28<span class="thinspace"></span>&amp;times;<span class="thinspace"></span>1017<span class="thinspace"></span>mol/cm<sup>2</sup> and 6<span class="thinspace"></span>&amp;times;<span class="thinspace"></span>1017<span class="thinspace"></span>mol/cm<sup>2</sup> respectively. These results are capable of representing known urban regions and biomass burning regions well throughout China, Southeast Asia, and South Asia, specifically including Beijing, Hebei, Shandong, Jiangsu, Anhui, Hunan, Guangdong, and Bangkok on one hand, and Northeastern India, Myanmar, Laos, Northern Thailand, and Vietnam on the other hand. A detailed analysis of the time series over the different classified regions show that while the urban areas have a much higher annual value, and a relatively long peak time, that their maximum is never as high as the peaks in the biomass burning regions, and that these peaks in the biomass burning regions are extremely short in duration, although they occur annually or bi-annually. Finally, we have not been able to obtain a statistically relevant decreasing trend, as others have found, making CO possibly an interesting species for future studies.</p>

scholarly journals Evaluation and enhancement of a low-cost NDIR CO<sub>2</sub> sensor

2017 ◽  
Author(s):  
Cory R. Martin ◽  
Ning Zeng ◽  
Anna Karion ◽  
Russell R. Dickerson ◽  
Xinrong Ren ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Standard Deviation ◽  
Low Cost ◽  
Linear Regression Analysis ◽  
Ambient Air ◽  
Multivariate Linear Regression Analysis ◽  
Laser Absorption ◽  
Accuracy And Precision ◽  
Carbon Dioxide Concentrations ◽  
Ambient Air Monitoring

Abstract. Non-dispersive infrared (NDIR) sensors are a low-cost way to observe carbon dioxide concentrations in air, but their specified accuracy and precision are not sufficient for some scientific applications. An initial evaluation of six SenseAir K30 carbon dioxide NDIR sensors in a lab setting showed that without any calibration or correction, the sensors have an individual root mean square (RMS) error between ~ 5 to 21 parts per million (ppm) compared to a research-grade greenhouse gas analyzer using cavity enhanced laser absorption spectroscopy. Through further evaluation, after correcting for environmental variables with coefficients determined through a multivariate linear regression analysis, the calculated difference between the each of six individual K30 NDIR sensors and the higher-precision instrument had for one minute data a standard deviation of between 1.6 ppm and 4.4 ppm. The median standard deviation improved from 8.08 for off the shelf sensors to 1.89 ppm after correction and calibration, demonstrating the potential to provide useful information for ambient air monitoring.

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