scholarly journals Progress report on addressing meteotsunami risk in the eastern Yellow Sea

2021 ◽  
Author(s):  
Myung-Seok Kim ◽  
Seung-Buhm Woo ◽  
Hyunmin Eom ◽  
Sung Hyup You
Keyword(s):  
Monitoring System ◽  
Yellow Sea ◽  
Pressure Sensors ◽  
Air Pressure ◽  
Coastal Hazards ◽  
Observation System ◽  
Maximum Height ◽  
Tide Gauges ◽  
Pressure Oscillations ◽  
Observation Systems

Abstract On March 31, 2007, strong, tsunami-like waves of 1.0–2.5 m were recorded at most tide gauges along the west coast of Korea. The following year, on May 4, unexpected, abnormal waves in the eastern Yellow Sea reached a maximum height of ~1.3 m. Both events occurred without warning, resulting in severe loss of life and property. Subsequent analysis found that these tsunami-like waves were meteotsunamis generated by air pressure oscillations. Evidence of possible meteotsunamis has been recorded by existing observation systems. However, the lack of a comprehensive, meteotsunami-specific observation system has hindered community preparedness, resulting in severe damage. We utilized existing observation systems (meteorological stations, tide gauges, and radar) during 2018 to develop a real-time meteotsunami monitoring system in the eastern Yellow Sea. This system detects the intensity and propagation of air pressure oscillations to identify potential coastal hazards and prevent damage caused by meteotsunamis. Two air pressure disturbance methods for assessing air pressure oscillation intensity (a range of pressure changes over a 60 min window vs. the rate of pressure change over a 10 min window) were compared, and several test operations were performed during development of the proposed system. The progress and limitations of the current observation and monitoring system were confirmed based on recent monitoring reports of air pressure jumps during the meteotsunamis on April 7, 2019. To address the insufficient lead time of meteotsunami warnings, installation and testing of open-ocean buoys outfitted with pressure sensors commenced in 2019.

scholarly journals Pressure-forced meteotsunami occurrences in the eastern Yellow Sea over the past decade (2010–2019): monitoring guidelines

2021 ◽  
Author(s):  
Myung‑Seok Kim ◽  
Seung‑Buhm Woo ◽  
Hyunmin Eom ◽  
Sung Hyup You
Keyword(s):  
Sea Level ◽  
Monitoring System ◽  
Yellow Sea ◽  
Tide Gauge ◽  
The Yellow Sea ◽  
Occurrence Rate ◽  
Risk Level ◽  
Observation System ◽  
Pressure Disturbance ◽  
The Past

Abstract. The eastern Yellow Sea meteotsunami occurrences between 2010 and 2019 and guidelines derived using favourable conditions of pressure disturbance (10 min rate of air pressure change) for meteotsunami generation are described. A total of 34 meteotsunami events over the past decade can be classified based on a current meteotsunami monitoring and observation system. 1 min intervals of mean sea level pressure and sea level observations from 89 meteorological stations and 16 tide gauges are analysed. Most of the classified meteotsunami events (76 %, 26/34) in the eastern Yellow Sea are found to be between February and June during the winter-to-summer transition, which shows a strong seasonal trend. The meteotsunami occurrences are spatially frequent at the DaeHeuksando (DH) tide gauge, known as a beacon tide gauge of the observation system. It appears that the specific characteristics (intensity, occurrence rate, and propagation) of the pressure disturbance are in common on extreme meteotsunami events that are classified by applying the hazardous meteotsunami conditions among the 34 events. For a risk level assessment of the eastern Yellow Sea meteotsunami occurrences, favourable conditions of the pressure disturbance for meteotsunami generation are utilized. Overall, this study can provide useful and practical guidelines such as operation period, potential hot spot, and risk level to monitoring system operators when operating the monitoring system of the Yellow Sea.

scholarly journals Experimental Study on Dynamic Combustion Characteristics in Swirl-Stabilized Combustors

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1609
Author(s):  
Donghyun Hwang ◽  
Kyubok Ahn
Keyword(s):  
Experimental Study ◽  
Heat Release ◽  
Dynamic Pressure ◽  
Combustion Instability ◽  
Flame Structure ◽  
Pressure Sensors ◽  
Necessary Condition ◽  
Rayleigh Criterion ◽  
Pressure Oscillations ◽  
Geometric Conditions

An experimental study was performed to investigate the combustion instability characteristics of swirl-stabilized combustors. A premixed gas composed of ethylene and air was burned under various flow and geometric conditions. Experiments were conducted by changing the inlet mean velocity, equivalence ratio, swirler vane angle, and combustor length. Two dynamic pressure sensors, a hot-wire anemometer, and a photomultiplier tube were installed to detect the pressure oscillations, velocity perturbations, and heat release fluctuations in the inlet and combustion chambers, respectively. An ICCD camera was used to capture the time-averaged flame structure. The objective was to understand the relationship between combustion instability and the Rayleigh criterion/the flame structure. When combustion instability occurred, the pressure oscillations were in-phase with the heat release oscillations. Even if the Rayleigh criterion between the pressure and heat release oscillations was satisfied, stable combustion with low pressure fluctuations was possible. This was explained by analyzing the dynamic flow and combustion data. The root-mean-square value of the heat release fluctuations was observed to predict the combustion instability region better than that of the inlet velocity fluctuations. The bifurcation of the flame structure was a necessary condition for combustion instability in this combustor. The results shed new insight into combustion instability in swirl-stabilized combustors.

scholarly journals Testing an “IoT” Tide Gauge Network for Coastal Monitoring

IoT ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 17-32
Author(s):  
Philip Knight ◽  
Cai Bird ◽  
Alex Sinclair ◽  
Jonathan Higham ◽  
Andy Plater
Keyword(s):  
Sea Level ◽  
Morphological Changes ◽  
Tide Gauge ◽  
Low Cost ◽  
Pressure Sensors ◽  
Wave Activity ◽  
Tide Gauges ◽  
Coastal Monitoring ◽  
Level Data ◽  
Operational Constraints

A low-cost “Internet of Things” (IoT) tide gauge network was developed to provide real-time and “delayed mode” sea-level data to support monitoring of spatial and temporal coastal morphological changes. It is based on the Arduino Sigfox MKR 1200 micro-controller platform with a Measurement Specialties pressure sensor (MS5837). Experiments at two sites colocated with established tide gauges show that these inexpensive pressure sensors can make accurate sea-level measurements. While these pressure sensors are capable of ~1 cm accuracy, as with other comparable gauges, the effect of significant wave activity can distort the overall sea-level measurements. Various off-the-shelf hardware and software configurations were tested to provide complementary data as part of a localized network and to overcome operational constraints, such as lack of suitable infrastructure for mounting the tide gauges and for exposed beach locations.

scholarly journals DESIGN OF TIRE PRESSURE MONITORING SYSTEM USING A PRESSURE SENSOR BASE

SINERGI ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 70 ◽  
Author(s):  
Lukman Medriavin Silalahi ◽  
Mudrik Alaydrus ◽  
Agus Dendi Rochendi ◽  
Muhtar Muhtar
Keyword(s):  
Monitoring System ◽  
Pressure Sensor ◽  
Electronic Device ◽  
Pressure Sensors ◽  
Pressure Level ◽  
Automotive Sector ◽  
Pressure Monitoring ◽  
Alert System ◽  
Tire Pressure ◽  
Tire Pressure Monitoring System

Currently, the Tire Pressure Monitoring System (TPMS) only monitors the condition of a tire pressure. However, there are no particular reactions taking place after the value of its tire pressure is discovered. In fact, the value of a tire pressure determines driving comfort and safety Therefore, this research proposed a method to integrate a TPMS and a Pressure Sensor Base (PSB) with a particular reaction required to fulfill tires automatically. The proposed TPMS has an electronic device unit directly attached to a tire’s valve. This unit includes pressure sensors, microcontrollers, Bluetooth transmitters and batteries. An alert system is generated whenever tire pressure exceeds the maximum or minimum safe pressure level. Moreover, if the pressure measured is below the lowest level of the desired pressure, it will automatically activate the compressor. Several experiments have been carried out to analyze the proposed system. The integrated TPMS has proven to be able to be an alternative tool for the automotive sector to keep maintaining the tires and to improve a driving comfort and safety.

scholarly journals Smart textile device for shooter’s fingers movement monitoring

2021 ◽  
pp. 1-13
Author(s):  
Adelina Vevere ◽  
Alexander Oks ◽  
Alexei Katashev ◽  
Galina Terlecka ◽  
Laima Saiva ◽  
...  
Keyword(s):  
Monitoring System ◽  
Grip Force ◽  
Index Finger ◽  
Pressure Sensors ◽  
Middle Finger ◽  
Smart Textile ◽  
Single Sensor ◽  
Fast Release ◽  
Movement Monitoring

BACKGROUND: The manner in which shooters pull the trigger may significantly affect the shooter’s results. Shooting coaches are often not able to detect incorrect pull because of gun movement during the shot and recoil. OBJECTIVE: Development of the smart-textile based trigger pull monitoring system and demonstration of its ability to distinguish correct and wrong triggering techniques. METHODS: Two separated knitted resistive pressure sensors were integrated over III and II phalanges in the index finger fingerstall; single sensor was integrated over both III and II phalanges of the middle finger fingerstall. Resistance of the sensors was measured in a course of shots, performed by expert shooter, which simulated typical novice’s trigger pull errors. RESULTS: Sensors’ resistance recordings were made for following erroneous trigger pull motions: pulling of the trigger with index finger’s II phalanx instead of III; fast and jerky trigger pull (trigger tear-off); too fast release of the trigger after shot; and excessive grip force, applied by middle finger. For each type of erroneous movement, recordings waveforms included distinguishable features that characterised a particular type of error. CONCLUSIONS: The developed trigger pull monitoring system provides signals that could be used for recognition of the incorrect trigger pull motions during gun shots.

SUBSTANTIATION OF PARAMETERS OF THE 3D CDP FIELD OBSERVATION SYSTEM

2021 ◽  
pp. 40-47
Author(s):  
A. P. Sysoev ◽  
Keyword(s):  
Comparative Analysis ◽  
Distribution Density ◽  
Second Step ◽  
Image Point ◽  
Observation System ◽  
Kirchhoff Migration ◽  
Observation Systems ◽  
The Common ◽  
Gaussian Beam Migration ◽  
The Relationship

The substantiation of parameters of the 3D observation system is considered from the perspective of the Kirchhoff migration. At the first step of this transformation, on the basis of diffraction transformation on a gather of CSP, the problem of wavelet extraction reflected from specified points of the medium (image points) is solved. The characteristic of the directivity of this transformation is determined by parameters of the arrangement of devices. At the second step, summation is performed by gathers of the common image point (СIP). The distribution density of the observation system sources determines the stacking fold by CIP. In the process of selecting survey parameters, the comparative analysis of equivalent observation systems with the same data properties for the migration task, but with different parameters of the observation system, is of great important. The relationship between the step of common midpoints of the observation system and the step of traces of resulting images of the medium is discussed. The Gaussian beam migration algorithm is considered as a method for solving the problem of constructing an image of the medium that correctly takes into account the irregularity of the initial data.

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