scholarly journals Coupled Delft3D-Object Model to Predict Mobility and Burial of Munition on Sandy Floor

2021 ◽  
Author(s):  
Peter C. Chu ◽  
Vinicius S. Pessanha ◽  
Chenwu Fan
Keyword(s):  
Sediment Transport ◽  
Time Series Data ◽  
Development Program ◽  
Environmental Research ◽  
Series Data ◽  
Physical Parameters ◽  
Object Model ◽  
Wave Direction ◽  
Peak Period ◽  
Rolling Moment

Coupled Delft3D-object model has been developed to predict object’s mobility and burial on sandy seafloor. The Delft3D model is used to predict seabed environment such as currents, waves (peak period, significant wave height, wave direction), water level, sediment transport, and seabed change, which are taken as the forcing term to the object model consisting of three components: (a) object‘s physical parameters such as diameter, length, mass, and rolling moment, (b) dynamics of rolling cylinder around its major axis, and (c) empirical sediment scour model with re-exposure parameterization. The model is compared with the observational data collected from a field experiment from 21 April to 23 May 2013 off the coast of Panama City, Florida funded by the Department of Defense Strategic Environmental Research and Development Program. The experimental data contain both objects’ mobility using sector scanning and pencil beam sonars and simultaneous environmental time series data of the boundary layer hydrodynamics and sediment transport conditions. Comparison between modeled and observed data clearly show the model capability.

scholarly journals Coupled Delft3D-Object Model to Predict Mobility of Munition on Sandy Seafloor

Fluids ◽  
2021 ◽  
Vol 6 (9) ◽  
pp. 330
Author(s):  
Peter C. Chu ◽  
Vinicius S. Pessanha ◽  
Chenwu Fan ◽  
Joseph Calantoni
Keyword(s):  
Experimental Data ◽  
Sediment Transport ◽  
Time Series Data ◽  
Major Axis ◽  
Series Data ◽  
Physical Parameters ◽  
Object Model ◽  
Wave Direction ◽  
Rolling Moment ◽  
Object Mobility

The coupled Delft3D-object model has been developed to predict the mobility and burial of objects on sandy seafloors. The Delft3D model is used to predict seabed environmental factors such as currents, waves (peak wave period, significant wave height, wave direction), water level, sediment transport, and seabed change, which are taken as the forcing term to the object model consisting of three components: (a) physical parameters such as diameter, length, mass, and rolling moment; (b) dynamics of the rolling cylinder around its major axis; (c) an empirical sediment scour model with re-exposure parameterization. The model is compared with the observational data collected from a field experiment from 21 April to 13 May 2013 off the coast of Panama City, Florida. The experimental data contain both object mobility using sector scanning sonars and maintenance divers as well as simultaneous environmental time series data of the boundary layer hydrodynamics and sediment transport conditions. Comparison between modeled and observed data clearly shows the model’s capabilities and limitations.

scholarly journals X-ray Flux and Spectral Variability of the TeV Blazars Mrk 421 and PKS 2155-304

Galaxies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 64
Author(s):  
Alok C. Gupta
Keyword(s):  
Black Hole ◽  
Time Series Data ◽  
Series Data ◽  
Physical Parameters ◽  
Electromagnetic Spectrum ◽  
Black Hole Mass ◽  
Spectral Variability ◽  
Massive Black Hole ◽  
X Ray ◽  
Northern And Southern Hemispheres

We reviewed X-ray flux and spectral variability properties studied to date by various X-ray satellites for Mrk 421 and PKS 2155-304, which are TeV emitting blazars. Mrk 421 and PKS 2155-304 are the most X-ray luminous blazars in the northern and southern hemispheres, respectively. Blazars show flux and spectral variabilities in the complete electromagnetic spectrum on diverse timescales ranging from a few minutes to hours, days, weeks, months and even several years. The flux and spectral variability on different timescales can be used to constrain the size of the emitting region, estimate the super massive black hole mass, find the dominant emission mechanism in the close vicinity of the super massive black hole, search for quasi-periodic oscillations in time series data and several other physical parameters of blazars. Flux and spectral variability is also a dominant tool to explain jet as well as disk emission from blazars at different epochs of observations.

scholarly journals Transfer functions: learning about a lagged exposure-outcome association in time-series data

2021 ◽  
Author(s):  
Hiroshi Mamiya ◽  
Alexandra M. Schmidt ◽  
Erica E. M. Moodie ◽  
David L. Buckeridge
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Transfer Functions ◽  
Environmental Research ◽  
Series Data ◽  
Time Lags ◽  
Food Purchasing ◽  
Lag Model ◽  
Time Lagged ◽  
Sugary Beverages

AbstractMany population exposures in time-series analysis, including food marketing, exhibit a time-lagged association with population health outcomes such as food purchasing. A common approach to measuring patterns of associations over different time lags relies on a finite-lag model, which requires correct specification of the maximum duration over which the lagged association extends. However, the maximum lag is frequently unknown due to the lack of substantive knowledge or the geographic variation of lag length. We describe a time-series analytical approach based on an infinite lag specification under a transfer function model that avoids the specification of an arbitrary maximum lag length. We demonstrate its application to estimate the lagged exposure-outcome association in food environmental research: display promotion of sugary beverages with lagged sales.

Applied Data Analytics to Buoy Records for Weather Window Evaluation

2021 ◽  
Author(s):  
Tirtharaj Bhaumik ◽  
Shiladitya Basu
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Data Analytics ◽  
Time Series Data ◽  
Weather Data ◽  
Series Data ◽  
Wave Direction ◽  
Significant Wave ◽  
Using Data ◽  
Future Work

This paper analyzes weather data recorded by typical oceanographic buoys using data analytics and regression techniques. Time series data over a period of more than four decades (1976 – 2020) are reviewed and profiled. A set of key variables including seasonality, wind speed, wind direction, wave period, wave direction, etc., are screened from the buoy measurements to build a predictive model based on multiple linear regression for significant wave height prediction. A sensitivity analysis is then conducted for the available weather window corresponding to specified threshold operational limits of the significant wave height. Key insights are presented along with suggestions for future work to assist marine operators in planning and derisking offshore operations. Utilizing the algorithms and workflows presented in this paper, a user can increase confidence in weather window prediction, and develop safer, efficient offshore operation plans.

Extremely peculiar spectrum of the primary component of the eclipsing binary HD 66051

2019 ◽  
Vol 15 (S350) ◽  
pp. 412-414
Author(s):  
E. Niemczura ◽  
P. A. Kołaczek-Szymański ◽  
F. Castelli ◽  
S. Hubrig ◽  
S. P. Järvinen ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Primary Component ◽  
Series Data ◽  
Physical Parameters ◽  
Orbital Parameters ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars ◽  
Chemical Peculiarity

AbstractHD 66051 is an eclipsing and spectroscopic double-lined binary (SB2), hosting two chemically peculiar stars: a highly peculiar B star as primary and an Am star as secondary. The investigation of the new high-resolution UVES spectrum of HD 66051 allowed us to decide on the chemical peculiarity type of both components with more reliability. An analysis of TESS photometric time series data will further specify the physical parameters of the stars and the orbital parameters of the system.

scholarly journals Experimental Analysis of Dynamic Interaction Between a Centrifugal Compressor and its Casing

2014 ◽  
Author(s):  
P. Almeida ◽  
C. Gibert ◽  
F. Thouverez ◽  
X. Leblanc ◽  
J.-P. Ousty
Keyword(s):  
Centrifugal Compressor ◽  
Time Series Data ◽  
Laser Doppler Vibrometer ◽  
Series Data ◽  
Physical Parameters ◽  
Full Spectrum ◽  
Scanning Laser Doppler Vibrometer ◽  
Recorded Data ◽  
Interaction Experiment ◽  
Run Up

In turbomachinery, one way to improve aerodynamic performance and reduce fuel consumption consists of minimizing the clearance between rotor and casing. Yet the probability of contact is increased and this may lead in some specific conditions to a large and even unstable excitation on the impeller and stator. To achieve better understanding of the dynamic behavior occurring during the blade-to-casing contact, many numerical studies have been conducted but only a few experiments have been reported in the literature thus far. The interaction experiment reported in this paper involves a low-pressure, rotating centrifugal compressor and its casing tested in a vacuum chamber. Contact is initiated by introducing a gap near zero, and certain events with significant dynamic levels are observed during the run-up. Measurements are performed using strain gauges on both the rotating and stationary parts and a Scanning Laser Doppler Vibrometer on the stator. This research focuses on an analysis of the recorded data. Time series data are also analyzed by means of standard signal processing and a full spectrum analysis in order to identify the direction of traveling wave propagation on the two structures as well as nodal diameters and frequencies. The dynamic response of structures is accompanied by variations in other physical parameters such as temperature, static deformed shapes, speed and torque. A wearing pattern is evaluated following the contact experiments. The spectral content of response is dominated by frequency modes excited by engine orders as well as by sidebands due to inherent system non-linearity.

scholarly journals Experimental Analysis of Dynamic Interaction Between a Centrifugal Compressor and Its Casing

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
P. Almeida ◽  
C. Gibert ◽  
F. Thouverez ◽  
X. Leblanc ◽  
J.-P. Ousty
Keyword(s):  
Centrifugal Compressor ◽  
Time Series Data ◽  
Laser Doppler Vibrometer ◽  
Series Data ◽  
Physical Parameters ◽  
Full Spectrum ◽  
Rotating Speed ◽  
Scanning Laser Doppler Vibrometer ◽  
System Nonlinearity ◽  
Run Up

In turbomachinery, one way to improve aerodynamic performance and reduce fuel consumption consists of minimizing the clearance between rotor and casing. Yet, the probability of contact is increased and this may lead in some specific conditions to a large and even unstable excitation on the impeller and stator. To achieve better understanding of the dynamic behavior occurring during the blade-to-casing contact, many numerical studies have been conducted but only a few experiments have been reported in the literature thus far. The interaction experiment reported in this paper involves a low-pressure, rotating centrifugal compressor and its casing tested in a vacuum chamber. Contact is initiated by introducing a gap near zero, and certain events with significant dynamic levels are observed during the run-up. Measurements are performed using strain gauges on both the rotating and stationary parts and a scanning laser Doppler vibrometer on the stator. This research focuses on an analysis of the recorded data. Time series data are also analyzed by means of standard signal processing and a full spectrum analysis in order to identify the direction of traveling wave propagation on the two structures as well as nodal diameters and frequencies. The dynamic response of structures is accompanied by variations in other physical parameters such as temperature, static deformed shapes, speed, and torque. A wearing pattern is evaluated following the contact experiments. The spectral content of response is dominated by frequency modes excited by rotating speed harmonics as well as by sidebands due to inherent system nonlinearity.

scholarly journals Prediction of groundwater trends for irrigation in Northern Bangladesh

2021 ◽  
Author(s):  
Mohammad Abid Hossain Mridha ◽  
Syed Hafizur Rahman
Keyword(s):  
Agricultural Production ◽  
Time Series Data ◽  
Coarse Sand ◽  
Northern Region ◽  
Series Data ◽  
Bengal Basin ◽  
Peak Period ◽  
Tube Wells ◽  
Dry Seasons ◽  
And Storage

Abstract Groundwater trends affect the domestic, agricultural, and industrial prospects of a region. The study area is Bogura, a northern region of Bangladesh, located on the Pleistocene terrace of the Bengal Basin. The aquifer consists of medium-to-coarse sand, located at a depth of 4.66–42.68 m; groundwater is scarce during dry seasons. The water table (WT) time-series data for 2007–2019 were used for forecasting and characterizing present and future groundwater conditions using existing numerical simulations. The annual groundwater budget for discharge and storage was 2,772 and 2,442 Mm3, respectively. Thus, the annual scarcity of groundwater was 330.4 Mm3 (13.5%), excluding the surface water contribution of 10 Mm3 (0.4%). The present spacing of deep tube wells (DTWs) and shallow tube wells (STWs) were 744 and 372 m, respectively. Currently, the DTW spacing ranged 744–800 m; however, the STW spacing of 250–372 m is higher than the set distance. Hence, further installations of STWs were strictly disallowed for irrigation. WT declined by 1.0 m in the last 13 years, i.e., 0.07 m or 1.2% decline rate per annum, causing water scarcity in the region during the peak period in the dry season (June–February), thus affecting irrigation and limiting agricultural production.

Application of Real-time Monitoring Buoy Systems for Physical and Biogeochemical Parameters in the Coastal Ocean around the Korean Peninsula

2005 ◽  
Vol 39 (2) ◽  
pp. 70-80 ◽  
Author(s):  
SungHyun Nam ◽  
Guebuem Kim ◽  
Kyung-Ryul Kim ◽  
Kuh Kim ◽  
Lawrence Oh Cheng ◽  
...  
Keyword(s):  
Real Time ◽  
Korean Peninsula ◽  
Time Series Data ◽  
Coastal Region ◽  
Series Data ◽  
Physical Parameters ◽  
Potential Contribution ◽  
Coastal Regions ◽  
Frequency Monitoring ◽  
Monitoring Buoy

We introduce technological achievements while developing real-time ocean monitoring buoy systems in the key coastal regions around the Korean peninsula, and highlight their potential contribution to oceanographic studies in the region. Major achievements are an integration of physical and biogeochemical sensors, real-time and two-way communication, sustainable maintenance with stable power supply and mooring design, and the two-way control of sensor and sampling strategies with high sampling rates (as often as every minute). The time-series data from two buoy systems deployed in the key coastal regions are given as examples to show their potential use in studying oceanographic issues, such as major current variations along the east coast of Korea, wind-driven episodic events including typhoon passages, and frequent changes due to internal wave passages. The real-time and high-frequency monitoring of biogeochemical properties of seawater together with physical parameters could be used for numerous oceanographic studies in the coastal region, i.e., air-sea gas exchange, harmful dinoflagellate bloom, interaction between physical and biogeochemical processes.

scholarly journals Contribution of Agricultural Sector Towards Regional Income Inequality of Sumatera Economic Corridor

2016 ◽  
Vol 1 (1) ◽  
pp. 019
Author(s):  
Dany Juhandi ◽  
Irham Irham ◽  
Jamhari Jamhari
Keyword(s):  
Income Inequality ◽  
Agricultural Sector ◽  
Time Series Data ◽  
Development Program ◽  
Series Data ◽  
Time Range ◽  
Master Plan ◽  
Regional Income Inequality ◽  
Economic Development Program ◽  
Secondary Time

Finding of previous studies shows that Sumatera Economic Corridor is categorized as the highest income inequality. The Indonesian goverment enacts MP3EI (Master Plan for the Acceleration and Expansion of Indonesia Economic Development) program to promote equitable development where each economic corridor owns strategic economic sector. The objective of this study is to analyze the contribution of agricultural sector on income inequality in Sumatera Economic Corridor (SEC) using a weighted coefficient of variation. We use secondary time series data of Gross Regional Domestic Product (GRDP), number of population, and per capita income of a time range between 2002 and 2013. Data analysis shows that agricultural sector has the least contribution on income inequality. Consequently, goverment policy should be focusing on the development of agricultural sector in Sumatera Economic Corridor

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