scholarly journals Local Variations in Broadband Sensor Installations: Orientations, Sensitivities, and Noise Levels

2021 ◽  
Author(s):  
A. T. Ringler ◽  
R. E. Anthony
Keyword(s):  
Background Noise ◽  
Human Error ◽  
Vertical Component ◽  
Geological Structure ◽  
Limiting Factor ◽  
Controlled Environment ◽  
Fiber Optic Gyroscope ◽  
Noise Levels ◽  
Alignment Technique ◽  
The Stability

AbstractAs seismologists continue to place more stringent demands on data quality, accurately described metadata are becoming increasingly important. In order to better constrain the orientation and sensitivities of seismometers deployed in U.S. Geological Survey networks, the Albuquerque Seismological Laboratory (ASL) has recently begun identifying true north with a fiber optic gyroscope (FOG) and has developed methodologies to constrain mid-band, vertical component sensitivity levels to less than 1% in a controlled environment. However, questions remain regarding the accuracy of this new alignment technique as well as if instrument sensitivities and background noise levels are stable when the seismometers are installed in different environmental settings. In this study, we examine the stability and repeatability of these parameters by reinstalling two high-quality broadband seismometers (Streckeisen STS-2.5 and Nanometrics T-360 Global Seismographic Network (GSN) version) at different locations around the ASL and comparing them to each other and a reference STS-6 seismometer that stayed stationary for the duration of the experiment. We find that even in different environmental conditions, the sensitivities of the two broadband seismometers stayed stable to within 0.1% and that orientations attained using the FOG are generally accurate to within a degree. However, one install was off by 5° due to a mistake made by the installation team. These results indicate that while technology and methodologies are now in place to calibrate and orient a seismometer to within 1°, human error both during the installation and while producing the metadata is often a limiting factor. Finally, we find that background noise levels at short periods (0.1–1 s) become noisier when the sensors are emplaced in unconsolidated materials, whereas the noise levels at long periods (30–100 s) are not sensitive to local geological structure on the vertical components.

Improving the methods to improve the stability of hydrotechnical structures in Yakutia

2020 ◽  
pp. 37-39
Author(s):  
M LOSKIN
Keyword(s):  
Agricultural Production ◽  
Hydraulic Engineering ◽  
Process Water ◽  
Small Rivers ◽  
Limiting Factor ◽  
Safe Operation ◽  
Central Yakutia ◽  
Agricultural Water Supply ◽  
Temperature Impact ◽  
The Stability

Problems of providing the population and agricultural production by qualitative potable and process water in the Central Yakutia are covered. This territory belongs to the region with acute shortage of water resources which is always a limiting factor of development of agricultural production. For the solution of this burning issue in the 80th years of the last century along the small rivers the systems of hydraulic engineering constructions providing requirements with process water practically of all settlements of the Central Yakutia were constructed. At a construction of all hydraulic engineering buildings the method of construction with preservation of soils of the basis of constructions in a frozen state was applied. When warming the climate which is observed in recent years hydraulic engineering constructions built in regions of a wide spread occurance of breeds of an ice complex and with the considerable volume of water weight, were especially vulnerable. On character and a design they experience continuous threat of damage and demand very attentive relation from the operating organizations. Taking this into account, safe operation of hydraulic engineering constructions in a zone of distribution of permafrost breeds demands new approaches. The article examines features of hydraulic engineering constructions’ operation of agricultural water supply objects in the Central Yakutia. Distinctiveness of hydraulic engineering constructions’ operation is that stability of constructions is intimately bound to temperature impact of a reservoir on ground dams’ body and the basis of constructions. The possibility of inclusion of ways for an intensification of a freezing of constructions in the structure of operational actions is studied. The new method on safe operation of hydraulic engineering constructions as prewinter abatement of the water level in a reservoir accounting volumes and norms of water consumption of the settlement is offered.

Nondestructive Test on Typical Roadway Supports of a Mine via Drilling Core and Ground Penetrating Radar

2011 ◽  
Vol 368-373 ◽  
pp. 2411-2416
Author(s):  
Jian Ping Han ◽  
Hai Peng Liu
Keyword(s):  
Ground Penetrating Radar ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Potential Threat ◽  
Real Performance ◽  
Design Requirements ◽  
And Performance ◽  
The Stability ◽  
Ground Penetrating ◽  
Drilling Core

Temporary or permanent supports are necessary in underground construction for maintaining the stability and limiting the damage of surrounding rock. Due to the uncertainty of geological structure, the specificity of the underground environment as well as other factors, the quality and performance of supporting structure are often difficult to satisfy the design requirements, which not only seriously affects the normal construction and operation of mines but also has the potential threat to the safety of underground production. In order to investigate the influence of the unfavorable geologic environment on supporting concrete and evaluate the real performance of roadway supports of a mine, 17 typical projects were chosen and the strength of supporting concrete was detected by nondestructive drilling core method. The result shows that the strength is widely less than the design value. Furthermore, 4 projects of them were investigated by the ground penetrating radar (GPR) in order to evaluate the feasibility of GPR in the performance investigation of the roadway supports of a mine. The results indicate that ground penetrating radar is capable of measuring the thickness of the support, the distribution of rebars and the defects of the surrounding rock.

The Canterbury Child's Aid: A Binaural Spatial Sensor for Research with Blind Children

1979 ◽  
Vol 73 (5) ◽  
pp. 179-184
Author(s):  
E. R. Strelow ◽  
J. T. Boys
Keyword(s):  
Future Development ◽  
Background Noise ◽  
Field Of View ◽  
Basic Operation ◽  
Noise Levels ◽  
Design Features ◽  
Blind Children ◽  
Automatic Level

A binaural sensory aid for research with blind children is described along with the rationale for its design features. The basic operation of this form of aid is described in detail with particular reference to those features that control the sensing parameters of range, direction and field of view. A novel automatic level controller which ensures that device sounds remain audible but not excessively loud, in spite of changes in background noise levels, is also described. The likely future development of these forms of sonic aids is discussed.

scholarly journals Background noise analysis in urban airport surroundings of Brazilian cities, Congonhas Airport, São Paulo

2016 ◽  
Vol 50 (0) ◽  
Author(s):  
Fabio Scatolini ◽  
Cláudio Jorge Pinto Alves
Keyword(s):  
Traffic Control ◽  
Background Noise ◽  
Noise Analysis ◽  
Exposure Level ◽  
Noise Levels ◽  
Sound Exposure ◽  
Operational Characteristics ◽  
Data Compilation ◽  
Noise Measurements ◽  
Noise Data

ABSTRACT OBJECTIVE To perform a quantitative analysis of the background noise at Congonhas Airport surroundings based on large sampling and measurements with no interruption. METHODS Measuring sites were chosen from 62 and 72 DNL (day-night-level) noise contours, in urban sites compatible with residential use. Fifteen sites were monitored for at least 168 hours without interruption or seven consecutive days. Data compilation was based on cross-reference between noise measurements and air traffic control records, and results were validated by airport meteorological reports. Preliminary diagnoses were established using the standard NBR-13368. Background noise values were calculated based on the Sound Exposure Level (SEL). Statistic parameters were calculated in one-hour intervals. RESULTS Only four of the fifteen sites assessed presented aircraft operations as a clear cause for the noise annoyance. Even so, it is possible to detect background noise levels above regulation limits during periods of low airport activity or when it closes at night. CONCLUSIONS All the sites monitored showed background noise levels above regulation limits between 7:00 and 21:00. In the intervals between 6:00-6:59 and 21:00-22:59 the noise data, when analyzed with the current airport operational characteristics, still allow the development of additional mitigating measures.

Stability of Horizontal Boundary Layers

2006 ◽  
Author(s):  
Jean-Yves Chemin ◽  
Benoit Desjardins ◽  
Isabelle Gallagher ◽  
Emmanuel Grenier
Keyword(s):  
Reynolds Number ◽  
Linear Stability ◽  
Mathematical Proof ◽  
Vertical Component ◽  
Ekman Layer ◽  
Numerical Results ◽  
Energy Estimates ◽  
Navier Stokes ◽  
The 1960S ◽  
The Stability

Let us now detail the stability properties of an Ekman layer introduced in Part I, page 11. First we will recall how to compute the critical Reynolds number. Then we will describe briefly what happens at larger Reynolds numbers. The first step in the study of the stability of the Ekman layer is to consider the linear stability of a pure Ekman spiral of the form where U∞ is the velocity away from the layer and ζ is the rescaled vertical component ζ = x3/√εν. The corresponding Reynolds number is Let us consider the Navier–Stokes–Coriolis equations, linearized around uE The problem is now to study the (linear) stability of the 0 solution of the system (LNSCε). If u=0 is stable we say that uE is linearly stable, if not we say that it is linearly unstable. Numerical results show that u=0 is stable if and only if Re<Rec where Rec can be evaluated numerically. Up to now there is no mathematical proof of this fact, and it is only possible to prove that 0 is linearly stable for Re<Re1 and unstable for Re>Re2 with Re1<Rec<Re2, Re1 being obtained by energy estimates and Re2 by a perturbative analysis of the case Re=∞. We would like to emphasize that the numerical results are very reliable and can be considered as definitive results, since as we will see below, the stability analysis can be reduced to the study of a system of ordinary differential equations posed on the half-space, with boundary conditions on both ends, a system which can be studied arbitrarily precisely, even on desktop computers (first computations were done in the 1960s by Lilly).

Background‐Noise Levels in Suburban Communities

1963 ◽  
Vol 35 (5) ◽  
pp. 779-780 ◽  
Author(s):  
Lewis S. Goodfriend ◽  
R. L. Cardinell ◽  
Paul B. Ostergaard ◽  
Ray Donley
Keyword(s):  
Background Noise ◽  
Noise Levels ◽  
Suburban Communities

Factors Affecting Protein Distribution and Structure in a Dried Droplet

2008 ◽  
Author(s):  
Vishard Ragoonanan ◽  
Alptekin Aksan
Keyword(s):  
Surface Flux ◽  
Secondary Flows ◽  
Controlled Environment ◽  
Biological Macromolecules ◽  
Protein Distribution ◽  
Sessile Droplet ◽  
Factors Affecting ◽  
The Stability ◽  
Contact Line Pinning ◽  
And Storage

Convective/diffusive drying of biopreservation solutions that contain biological macromolecules or organisms is widely-utilized, especially in desiccated and vitrified state preservation. Typically, solutions are deposited on a surface as thin films or droplets and are dried in a controlled environment. A typical biopreservation solution contains the biomaterial to be preserved, non-reducing sugars (trehalose, sucrose, etc.), polyols, and salts [1]. There are several factors that affect the overall stabilization and storage efficiency of a biopreservation solution: the properties of the chemicals in the solution, the thermodynamic state of the product to be stabilized, the processing conditions, and the interactions of the solution with the surface it is dried on. For example, during drying of a sessile droplet in a low relative humidity environment, secondary flows form within the droplet due to contact line pinning and non-uniform surface flux. These flows mainly cause accumulation of solutes at the droplet’s periphery [2]. An additional factor is the specific interactions among the constituents of the biopreservation solution, which can affect the stability of the biological material.

Sparsified nightly fish chorusing in the Dry Tortugas during elevated background noise levels due to a tropical storm

2017 ◽  
Vol 141 (5) ◽  
pp. 3944-3944
Author(s):  
Benjamin S. Gottesman ◽  
Dante Francomano ◽  
Taylor Broadhead ◽  
Bryan C. Pijanowski
Keyword(s):  
Background Noise ◽  
Tropical Storm ◽  
Noise Levels ◽  
Dry Tortugas

Auditory and Visual Effects on Solutions to Computerized Mathematics Problems as a Function of Rate of Digit Presentation ,

1989 ◽  
Vol 69 (3-2) ◽  
pp. 1127-1130 ◽  
Author(s):  
William F. Vitulli ◽  
Connie P. Anderson
Keyword(s):  
Background Noise ◽  
Sound Pressure ◽  
Paired Comparison ◽  
Noise Levels ◽  
Visual Effects ◽  
Mathematics Problems ◽  
Exploratory Investigation ◽  
Significant Difference ◽  
Masking Noise ◽  
Post Hoc

This exploratory investigation concerned the effects of both auditory and visual stimulus variations on the accuracy of mental solutions to addition problems presented on a computer screen (CRT). 5 intensities of background noise and 5 background hues were presented randomly to 123 undergraduate volunteers as they mentally summed 25 numerals ranging from 1 to 5 at rates of either 1 sec. or 3 sec. per numeral timed from the onset of the previous numeral. A 2 × 2 × 5 mixed split-plot factorial analysis of variance gave a significant difference in errors between rates of digit presentation with greater accuracy associated with the 3-sec. rate. There was no significant difference in mean errors for auditory vs color modalities, yet a post hoc Newman-Keuls paired-comparison test of decibel levels at the 1-sec. rate of digit presentation gave a significant difference in mean errors between 60-dB and 70-dB sound-pressure levels (SPLs) of white masking noise. Also, a post hoc F test on differences between successive stages indicated significant differences suggesting a “learning set.” Comparisons between ‘everyday’ instances of these noise levels are made with implications for optimal computational environments.

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