scholarly journals Real-time setup to measure radon emission during rock deformation: implications for geochemical surveillance

2015 ◽  
Vol 4 (1) ◽  
pp. 111-119 ◽  
Author(s):  
P. Tuccimei ◽  
S. Mollo ◽  
M. Soligo ◽  
P. Scarlato ◽  
M. Castelluccio
Keyword(s):  
Real Time ◽  
Volcanic Eruptions ◽  
Displacement Transducer ◽  
Rock Deformation ◽  
Axial Deformation ◽  
Creep Tests ◽  
Stress Strain ◽  
Solid State Detector ◽  
Accumulation Chamber ◽  
Linear Variable Displacement Transducer

Abstract. Laboratory experiments can represent a valid approach to unravel the complex interplay between the geochemical behaviour of radon and rock deformation mechanisms. In light of this, we present a new real-time experimental setup for analysing in continuum the alpha-emitting 222Rn and 220Rn daughters over variable stress–strain regimes. The most innovative segment of this setup consists of the radon accumulation chamber obtained from a tough and durable material that can host large cylindrical rock samples. The accumulation chamber is connected, in a closed-loop configuration, to a gas-drying unit and to a RAD7 radon monitor. A recirculating pump moves the gas from the rock sample to a solid-state detector for alpha counting of radon and thoron progeny. The measured radon signal is enhanced by surrounding the accumulation chamber with a digitally controlled heating belt. As the temperature is increased, the number of effective collisions of radon atoms increases favouring the diffusion of radon through the material and reducing the analytical uncertainty. The accumulation chamber containing the sample is then placed into a uniaxial testing apparatus where the axial deformation is measured throughout a linear variable displacement transducer. A dedicated software allows obtaining a variety of stress–strain regimes from fast deformation rates to long-term creep tests. Experiments conducted with this new real-time setup have important ramifications for the interpretation of geochemical anomalies recorded prior to volcanic eruptions or earthquakes.

scholarly journals Real-time setup to record radon emission during rock deformation: implications for geochemical surveillance

2015 ◽  
Vol 5 (1) ◽  
pp. 39-62 ◽  
Author(s):  
P. Tuccimei ◽  
S. Mollo ◽  
M. Soligo ◽  
P. Scarlato ◽  
M. Castelluccio
Keyword(s):  
Real Time ◽  
Volcanic Eruptions ◽  
Displacement Transducer ◽  
Rock Deformation ◽  
Axial Deformation ◽  
Creep Tests ◽  
Stress Strain ◽  
Solid State Detector ◽  
Accumulation Chamber ◽  
Linear Variable Displacement Transducer

Abstract. Laboratory experiments can represent a valid approach to unravel the complex interplay between the geochemical behaviour of radon and rock deformation mechanisms. In light of this, we present a new real-time experimental setup for analyzing in continuum the alpha-emitting 222Rn and 220Rn daughters over variable stress–strain regimes. The most innovative segment of this setup consists of the radon accumulation chamber obtained from a tough and durable material that can host large cylindrical rock samples. The accumulation chamber is connected, in a closed-loop configuration, to a gas-drying unit and to a RAD7 radon monitor. A re-circulating pump moves the gas from the rock sample to a solid-state detector for alpha counting of radon and thoron progeny. The measured radon signal is enhanced by surrounding the accumulation chamber with a digitally controlled heating belt. As the temperature is increased, the number of effective collision of radon atoms increases favouring the diffusion of radon through the material and reducing the analytical uncertainty. The accumulation chamber containing the sample is then placed into an uniaxial testing apparatus where the axial deformation is measured throughout a linear variable displacement transducer. A dedicated software allows to obtain a variety of stress–strain regimes from fast deformation rates to long-term creep tests. Experiments conducted with this new real-time setup have important ramifications for the interpretation of geochemical anomalies recorded prior to volcanic eruptions or earthquakes.

scholarly journals Near-real-time volcanic cloud monitoring: insights into global explosive volcanic eruptive activity through analysis of Volcanic Ash Advisories

2021 ◽  
Vol 83 (2) ◽  
Author(s):  
S. Engwell ◽  
L. Mastin ◽  
A. Tupper ◽  
J. Kibler ◽  
P. Acethorp ◽  
...  
Keyword(s):  
Real Time ◽  
Volcanic Activity ◽  
Volcanic Ash ◽  
Source Parameters ◽  
Volcanic Eruptions ◽  
Volcanic Hazards ◽  
Process Data ◽  
Cloud Monitoring ◽  
Satellite Sensors ◽  
Volcanic Cloud

AbstractUnderstanding the location, intensity, and likely duration of volcanic hazards is key to reducing risk from volcanic eruptions. Here, we use a novel near-real-time dataset comprising Volcanic Ash Advisories (VAAs) issued over 10 years to investigate global rates and durations of explosive volcanic activity. The VAAs were collected from the nine Volcanic Ash Advisory Centres (VAACs) worldwide. Information extracted allowed analysis of the frequency and type of explosive behaviour, including analysis of key eruption source parameters (ESPs) such as volcanic cloud height and duration. The results reflect changes in the VAA reporting process, data sources, and volcanic activity through time. The data show an increase in the number of VAAs issued since 2015 that cannot be directly correlated to an increase in volcanic activity. Instead, many represent increased observations, including improved capability to detect low- to mid-level volcanic clouds (FL101–FL200, 3–6 km asl), by higher temporal, spatial, and spectral resolution satellite sensors. Comparison of ESP data extracted from the VAAs with the Mastin et al. (J Volcanol Geotherm Res 186:10–21, 2009a) database shows that traditional assumptions used in the classification of volcanoes could be much simplified for operational use. The analysis highlights the VAA data as an exceptional resource documenting global volcanic activity on timescales that complement more widely used eruption datasets.

scholarly journals Electro-Hydraulic Proportional System Real Time Tracking Control Development Based on Pulse width Modulation Method

2021 ◽  
Vol 23 (4) ◽  
pp. B336-B345
Author(s):  
Ezz Eldin Ibrahim ◽  
Tarek Elnady ◽  
Mohamed Saffaa Hassan ◽  
Ibrahim Saleh
Keyword(s):  
Real Time ◽  
Tracking Control ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Modulation Method ◽  
Constant Input ◽  
Transient Time ◽  
Linear Variable Displacement Transducer ◽  
Real Time Tracking

The presented work was directed to develop the dynamic performance of an electro-hydraulic proportional system (EHPS). A mathematical model of the EHPS is presented using electro- hydraulic proportional valve (EHPV) by Matlab-Simulink, which facilitates the simulation of the hydraulic behavior inside the main control unit. Experimental work is done and the closed loop system is designed using the linear variable displacement transducer sensor (LVDT). The controller of the system is an Arduino uno, which is considered as a processor of the system. The model is validated by the experimental system. The study also presents a real time tracking control method, based on pulse width modulation, by controlling the speed of the actuator to achieve the position tracking with minimum error and low transient time, by applying the constant input signal 50mm the transient time was 0.9 seconds and the error 1.8%.

Volcanic Eruptions, Real-Time Forecasting of

2015 ◽  
pp. 1-16 ◽  
Author(s):  
Andrew F. Bell ◽  
Christopher R. J. Kilburn ◽  
Ian G. Main
Keyword(s):  
Real Time ◽  
Volcanic Eruptions

Micro Impact Testing of Lead Free Solder Joints

2008 ◽  
Vol 32 ◽  
pp. 99-102
Author(s):  
Ranjan Rajoo ◽  
Erich H. Kisi ◽  
D.J. O'Connor
Keyword(s):  
Solder Joint ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Intermetallic Layer ◽  
Displacement Transducer ◽  
Impact Testing ◽  
Lead Free ◽  
Linear Variable Displacement Transducer ◽  
Free Solder

This paper presents data obtained from a newly-developed instrument to test the quality of solder interconnections at high strain rate – the ‘micro-impactor’. This shear test of the interconnection at high strain rate mimics the stress experienced by the solder joint when undergoing shock due to drop-impact. Instrumented with a load cell and linear variable displacement transducer (LVDT), it also has the ability to provide dynamic impact force and displacement data. Earlier concepts to characterise the solder joint at high strain rates such as the miniature pendulum impact tester [1] lacked this capability. This micro-impactor was used to study the effect of increasing silver (Ag) and copper (Cu) concentration in solder alloys on the shear strength of the solder joint. The performance of these lead-free alloys was also compared to that of the well-established leaded solder. It was found that increasing the silver content increases the yield strength of the solder, causing the failure to occur at the brittle intermetallic layer instead of in the bulk of the solder.

scholarly journals Recognizing Eruptions of Mount Etna through Machine Learning Using Multiperspective Infrared Images

2020 ◽  
Vol 12 (6) ◽  
pp. 970 ◽  
Author(s):  
Claudia Corradino ◽  
Gaetana Ganci ◽  
Annalisa Cappello ◽  
Giuseppe Bilotta ◽  
Sonia Calvari ◽  
...  
Keyword(s):  
Machine Learning ◽  
Decision Tree ◽  
Real Time ◽  
Volcanic Eruptions ◽  
Mount Etna ◽  
Depth Information ◽  
Bag Of Words ◽  
Infrared Images ◽  
Eruptive Activity ◽  
Thermal Cameras

Detecting, locating and characterizing volcanic eruptions at an early stage provides the best means to plan and mitigate against potential hazards. Here, we present an automatic system which is able to recognize and classify the main types of eruptive activity occurring at Mount Etna by exploiting infrared images acquired using thermal cameras installed around the volcano. The system employs a machine learning approach based on a Decision Tree tool and a Bag of Words-based classifier. The Decision Tree provides information on the visibility level of the monitored area, while the Bag of Words-based classifier detects the onset of eruptive activity and recognizes the eruption type as either explosion and/or lava flow or plume degassing/ash. Applied in real-time to each image of each of the thermal cameras placed around Etna, the proposed system provides two outputs, namely, visibility level and recognized eruptive activity status. By merging these outcomes, the monitored phenomena can be fully described from different perspectives to acquire more in-depth information in real time and in an automatic way.

Real time SAXS/stress–strain studies of thermoplastic polyurethanes at large strains

Polymer ◽  
2002 ◽  
Vol 43 (19) ◽  
pp. 5197-5207 ◽  
Author(s):  
D.J Blundell ◽  
G Eeckhaut ◽  
W Fuller ◽  
A Mahendrasingam ◽  
C Martin
Keyword(s):  
Real Time ◽  
Large Strains ◽  
Stress Strain ◽  
Thermoplastic Polyurethanes

Methods for the Experimental Evaluation of True Stress-Strain Curves After Necking of Conventional Tensile Specimens: Exploratory Investigation and Proposals

2012 ◽  
Author(s):  
Grace Kelly Q. Ganharul ◽  
Nick de Brangança Azevedo ◽  
Gustavo Henrique B. Donato
Keyword(s):  
Real Time ◽  
Weighted Average ◽  
Tensile Tests ◽  
Plastic Instability ◽  
True Stress ◽  
Experimental Results ◽  
Uniaxial Tensile ◽  
High Definition ◽  
Stress Strain

Numerical elastic-plastic simulations have undergone significant expansion during the last decades (e.g. refined fracture mechanics finite element models including ductile tearing). However, one limitation to increase the accuracy of such models is the reliable experimental characterization of true stress-strain curves from conventional uniaxial tensile tests after necking (plastic instability), which complicates the direct assessment of the true stress-strain curves until failure. As a step in this direction, this work presents four key activities: i) first, existing correction methods are presented, including Bridgman, power law, weighted average and others; ii) second, selected metals are tested to experimentally characterize loads and the geometric evolution of necking. High-definition images are used to obtain real-time measurements following a proposed methodology; iii) third, refined non-linear FEM models are developed to reproduce necking and assess stresses as a function of normalized neck geometry; iv) finally, existing correction methods are critically compared to experimental results and FEM predictions in terms of potential and accuracy. The experimental results evaluated using high-definition images presented an excellent geometrical characterization of instability. FEM models were able to describe stress-strain-displacement fields after necking, supporting the exploratory validations and proposals of this work. Classical methodologies could be adapted based on experiments to provide accurate stress-strain curves up to failure with less need for real-time measurements, thus giving further support to the determination of true material properties considering severe plasticity.

Drained creep of undisturbed cohesive marine sediments

1994 ◽  
Vol 31 (6) ◽  
pp. 841-855 ◽  
Author(s):  
W.-M. Tian ◽  
A.J. Silva ◽  
G.E. Veyera ◽  
M.H. Sadd
Keyword(s):  
Stress Level ◽  
Simple Shear ◽  
Test Duration ◽  
Time Behavior ◽  
Creep Tests ◽  
Shear Creep ◽  
Central Pacific ◽  
Stress Strain ◽  
The North ◽  
Triaxial Creep

Long-term, drained triaxial creep and direct simple shear creep tests were conducted on undisturbed marine specimens from the Gulf of Mexico and the north-central Pacific. Results indicated that time-dependent deformations can be represented by a power law equation, and the creep strain rate can be represented by an equation similar to that suggested earlier by other researchers. However, it was found that the m parameter suggested by these scientists was not a constant but dependent on stress level and sediment plasticity. Ageing effects were evidenced in triaxial specimens by the increase of shear strength with both test duration and stress level. The results provided a guide for the development of mathematical stress–strain–time relationships that will be developed in a separate paper. Key words : drained triaxial creep, simple shear creep, stress–strain–time behavior.

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