scholarly journals Analysis of the Possibility of Remote Laser Detection of Propane Leaks

2020 ◽  
pp. 1-12
Author(s):  
M. L. Belov ◽  
K. S. Titarenko ◽  
V. A. Gorodnichev
Keyword(s):  
Pressure Sensors ◽  
Correct Detection ◽  
Remote Detection ◽  
Concentration Limit ◽  
False Alarms ◽  
Laser Detection ◽  
Low Intensity ◽  
Information Parameter ◽  
Order Of Magnitude ◽  
Line Pressure

Propane is one of the main components of the wide fraction of light hydrocarbons (WLHF). A large volume of WLHF is transported to petrochemical plants via pipelines. Control of pipelines is carried out by means of in-line pressure sensors. However, they are ineffective for detecting low-intensity leaks.To detect low-intensity propane leaks from pipelines, it is promising to use a remote laser gas analyzer installed on an aircraft.The article is devoted to the analysis of the possibilities of remote laser detection of propane leaks.Based on the data on the absorption of propane and atmospheric gases, the wavelengths of 3370 nm (in the maximum absorption of propane) and 3550 nm (in the spectral region where there is no absorption of propane) were chosen as the sounding wavelengths.It was believed that the monitoring of propane leaks is carried out by a lidar installed on the aircraft in a monostatic sensing scheme. The method of differential absorption with scattering from the earth's surface is used.To detect propane leaks, an information parameter was used, which is equal to the ratio of the power recorded by the receiver at wavelengths of 3370 nm and 3550 nm. The value of the information parameter was calculated for different heights of the propane layer on the earth's surface and different concentrations of propane in the layer.Statistical modeling was performed to quantify the effectiveness of remote detection of propane leaks.In the work, the probability of correct detection of a propane leak (detection of a leak when it is in reality) and the probability of false alarms (detection of a leak when it is not in reality) were calculated.The decision to detect propane leaks was made when the value of the information parameter was less than the threshold.The results of mathematical modeling show that for a propane content in the leak of at least 0.17 % (an order of magnitude less than the concentration limit of flame propagation), the problem of remote detection of propane leaks from the pipeline can be solved with a probability of correct detection of more than 0.999 and a probability of false alarms of less than 0.001 with a thickness of the propane layer on the earth's surface of at least 20 cm.

scholarly journals Tunable In Situ 3D-Printed PVDF-TrFE Piezoelectric Arrays

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5032
Author(s):  
Alec Ikei ◽  
James Wissman ◽  
Kaushik Sampath ◽  
Gregory Yesner ◽  
Syed N. Qadri
Keyword(s):  
3D Printing ◽  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Mechanical Strain ◽  
Pressure Sensors ◽  
Strain Ratio ◽  
Ex Situ ◽  
Order Of Magnitude ◽  
3D Printed

In the functional 3D-printing field, poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) has been shown to be a more promising choice of material over polyvinylidene fluoride (PVDF), due to its ability to be poled to a high level of piezoelectric performance without a large mechanical strain ratio. In this work, a novel presentation of in situ 3D printing and poling of PVDF-TrFE is shown with a d33 performance of up to 18 pC N−1, more than an order of magnitude larger than previously reported in situ poled polymer piezoelectrics. This finding paves the way forward for pressure sensors with much higher sensitivity and accuracy. In addition, the ability of in situ pole sensors to demonstrate different performance levels is shown in a fully 3D-printed five-element sensor array, accelerating and increasing the design space for complex sensing arrays. The in situ poled sample performance was compared to the performance of samples prepared through an ex situ corona poling process.

scholarly journals Was the Devonian geomagnetic field dipolar or multipolar? Palaeointensity studies of Devonian igneous rocks from the Minusa Basin (Siberia) and the Kola Peninsula dykes, Russia

2017 ◽  
Vol 209 (2) ◽  
pp. 1265-1286 ◽  
Author(s):  
V V Shcherbakova ◽  
A J Biggin ◽  
R V Veselovskiy ◽  
A V Shatsillo ◽  
L M A Hawkins ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Geomagnetic Field ◽  
Mantle Convection ◽  
Geological Time ◽  
Southern Siberia ◽  
Planetary Evolution ◽  
Low Intensity ◽  
Order Of Magnitude ◽  
Earth’S Climate ◽  
The Impact

Abstract Defining variations in the behaviour of the geomagnetic field through geological time is critical to understanding the dynamics of Earth's core and its response to mantle convection and planetary evolution. Furthermore, the question of whether the axial dipole dominance of the recent palaeomagnetic field persists through the whole of Earth's history is fundamental to determining the reliability of palaeogeographic reconstructions and the efficacy of the magnetosphere in shielding Earth from solar wind radiation. Previous palaeomagnetic directional studies have suggested that the palaeofield had a complex configuration in the Devonian period (419–359 Ma). Here we present new high-quality palaeointensity determinations from rocks aged between 408 and 375 Ma from the Minusa Basin (southern Siberia), and the Kola Peninsula that enable the first reliable investigation of the strength of the field during this enigmatic period. Palaeointensity experiments were performed using the thermal Thellier, microwave Thellier and Wilson methods on 165 specimens from 25 sites. Six out of eight successful sites from the Minusa Basin and all four successful sites from the Kola Peninsula produced extremely low palaeointensities (<10 μT). These findings challenge the uniformitarian view of the palaeomagnetic field: field intensities of nearly an order of magnitude lower than Neogene values (except during relatively rare geomagnetic excursions and reversals) together with the widespread appearance of strange directions found in the Devonian suggest that the Earth's field during this time may have had a dominantly multipolar geometry. A persistent, low intensity multipolar magnetic field and associated diminished magnetosphere would increase the impact of solar particles on the Earth's magnetosphere, ionosphere and atmosphere with potential major implications for Earth's climate and biosphere.

Emerging investigator series: the effect of wildfire on streamwater mercury and organic carbon in a forested watershed in the southeastern United States

2017 ◽  
Vol 19 (12) ◽  
pp. 1505-1517 ◽  
Author(s):  
Allison M. Jensen ◽  
Todd M. Scanlon ◽  
Ami L. Riscassi
Keyword(s):  
United States ◽  
Organic Carbon ◽  
Suspended Solids ◽  
Southeastern United States ◽  
Forested Watershed ◽  
Low Intensity ◽  
Order Of Magnitude

The amount of streamwater mercury associated with suspended solids was an order of magnitude greater following a low-intensity wildfire.

scholarly journals Molecularly Imprinted Sol-Gel for TNT Detection with Optical Micro-Ring Resonator Sensor Chips

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3909 ◽  
Author(s):  
Ludmila Eisner ◽  
Isabel Wilhelm ◽  
Günter Flachenecker ◽  
Jürgen Hürttlen ◽  
Wolfgang Schade
Keyword(s):  
Gas Phase ◽  
Ring Resonator ◽  
Sol Gel ◽  
False Alarms ◽  
Organic Substances ◽  
Molecularly Imprinted ◽  
Precise Analysis ◽  
Order Of Magnitude ◽  
Tnt Detection ◽  
Receptor Layer

A sensor for trinitrotoluene (TNT) detection was developed by using a combination of optical micro-ring technology and a receptor coating based on molecularly imprinted sol-gel layers. Two techniques for deposition of receptor layers were compared: Airbrush technology and electrospray ionization. A concentration of less than 5 ppb for TNT in the gas-phase, using electrospray deposition of the receptor layer, was detected. The cross-sensitivities to organic substances and further nitro-based explosives were compared. As a result, the sensitivity to TNT is about one order of magnitude higher in comparison to the explosives 2,4-dinitrotoluene (DNT) or 1,3-dinitrobenzene (DNB) and about four orders of magnitude higher than the organic substances phenol, ethanol, and acetone. The signal response of the sensor is fast, and the compact sensor design enables the deposition of different receptor layers on multiple optical micro-rings on one chip, which allows a more precise analysis and reduction of side effects and false alarms.

scholarly journals An Iterative Run-to-Run Learning Model to Derive Continuous Brachial Pressure Estimates from Arterial and Venous Lines During Dialysis Treatment

2020 ◽  
Author(s):  
Jill Stewart ◽  
Paul Stewart ◽  
Thomas Walker ◽  
Daniela Viramontes Horner ◽  
Bethany Lucas ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Real Time ◽  
Brachial Artery ◽  
Pressure Sensors ◽  
Routine Practice ◽  
Mathematical Function ◽  
Arterial Line ◽  
Physiological Measurement ◽  
Measurement Validation ◽  
Line Pressure

Objective: Non-invasive continuous blood pressure monitoring is not yet part of routine practice in renal dialysis units but could be a valuable tool in the detection and prevention of significant variations in patient blood pressure during treatment. Feasibility studies have delivered an initial validation of a method which utilises pressure sensors in the extra-corporeal dialysis circuit, without any direct contact with the person receiving treatment. Our main objective is to further develop this novel methodology from its current early development status to a continuous-time brachial artery pressure estimator.Method: During an in vivo patient feasibility study with concurrent measurement validation by Finapres Nova experimental physiological measurement device, real-time continuous dialysis line pressures, and intermittent occluding arm cuff pressure data were collected over the entire period of (typically 4-hour) dialysis treatments. There was found to be an underlying quasi-linear relationship between arterial line and brachial pressure measurements which supported the development of a mathematical function to describe the relationship between arterial dialysis line pressure and brachial artery BP. However, unmodelled non-linearities, dynamics and time-varying parameters present challenges to the development of an accurate BP estimation system. In this paper, we start to address the problem of physiological parameter time variance by novel application of an iterative learning run-to-run modeling methodology originally developed for process control engineering applications to a parameterised BP model.Results: The iterative run-to-run learning methodology was applied to the real-time data measured during an observational study in 9 patients, supporting subsequent development of an adaptive real-time BP estimator. Tracking of patient BP is analysed for all the subjects in our patient study, supported only by intermittent updates from BP cuff measurements. Conclusion: The methodology and associated technology is shown to be capable of tracking patient BP non-invasively via arterial line pressure measurement during complete 4-hour treatment sessions. A robust and tractable method is demonstrated, and future refinements to the approach are defined.

Fault’s hydraulic diffusivity enhancement during injection induced fault reactivation: application of pore pressure diffusion inversions to laboratory injection experiments

2020 ◽  
Vol 223 (3) ◽  
pp. 2117-2132
Author(s):  
M Almakari ◽  
H Chauris ◽  
F Passelègue ◽  
P Dublanchet ◽  
A Gesret
Keyword(s):  
Fluid Flow ◽  
Fluid Pressure ◽  
Pressure Sensors ◽  
Order Effect ◽  
Fault Reactivation ◽  
Time Range ◽  
Hydraulic Diffusivity ◽  
Effective Normal Stress ◽  
Geological Conditions ◽  
Order Of Magnitude

SUMMARY In situ observations of fluid induced fault slip reactivation, as well as the analysis of induced seismicity have demonstrated the complexity of fluid–fault interactions under geological conditions. If fluid flow commonly reactivates faults in the form of aseismic slip or earthquakes, the resulting shear deformation causes strong modifications of the hydraulic properties. In this context, the relationship between slip front and fluid front on deep faults remains not fully understood. In this study, we investigate shear induced fluid flow and hydraulic diffusivity enhancement during fracture shearing in the laboratory. We use a series of injection reactivation tests, conducted under triaxial conditions, at different confining pressures (30, 60 and 95 MPa). The evolution of the fluid pressure along the saw-cut Andesite rock sample was monitored by two pressure sensors, at two opposite locations of the experimental fault. We estimate the history of the effective hydraulic diffusivity (and its associated uncertainties) governing the experimental fault, using the pressure history at two points on the fault. For this, we develop a deterministic and a probabilistic inversion procedure, which is able to reproduce the experimental data for a wide time range of the different experiments. In this study, the hydraulic diffusivity increases by one order of magnitude through the injection experiment. Hydraulic diffusivity changes are mainly governed by the reduction of the effective normal stress acting on the fault plane, with a second-order effect of the shear slip.

FIBER LASER HYDROPHONES AS PRESSURE SENSORS

2006 ◽  
Vol 21 (supp01) ◽  
pp. 102-106
Author(s):  
P. E. BAGNOLI ◽  
N. BEVERINI ◽  
E. CASTORINA ◽  
E. FALCHINI ◽  
R. FALCIAI ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Acoustic Waves ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Single Mode ◽  
High Energy ◽  
Single Mode Fiber ◽  
Wavelength Shift ◽  
Order Of Magnitude

The development of hydro-phonic sensors for deep see acoustic detection is described. The sensitive element is an erbium-doped single mode fiber laser, with the cavity delimited by two Bragg grating reflectors. The variations of temperature and pressure perturb the cavity, inducing a wavelength shift. The very narrow emission band of the laser, together with the interferometric detection technique, allows a dynamic pressure sensitivity in the μ Pa range. The devices have been characterized both optically and acoustically in a closed tub. A resin coating of the fiber laser has been experimented: this technique improves the sensitivity by more than one order of magnitude. The high sensitivity makes these sensors suitable for the detection of the acoustic waves induced in water by Ultra High Energy Neutrinos.

scholarly journals Analysing detection bands of two-spectral reflection method to identify forest species composition

2021 ◽  
Vol 2094 (4) ◽  
pp. 042035
Author(s):  
M L Belov ◽  
A M Belov ◽  
V A Gorodnichev ◽  
S V Alkov
Keyword(s):  
Tree Species ◽  
Correct Detection ◽  
Temperate Climate ◽  
False Alarms ◽  
Subtropical Climate ◽  
Reflection Method ◽  
Climate Zone ◽  
Spectral Reflection ◽  
Broadleaved Tree Species ◽  
Broadleaved Tree

Abstract The optical reflection method is considered for detection of the forest areas where coniferous or broadleaved trees are dominant. Statistical modelling of correct detection and false alarm probabilities for identifying dominant (coniferous or broadleaved) tree species by the two-spectral reflection method has been conducted. It has been shown that monitoring enables us to identify dominant (coniferous or broadleaved) tree species with correct detection probability close to 1 and false alarms probability ~ second decimal places for the temperate climate zone at the wavelengths of 532 and 1540 nm or 532 and 1480 nm. As to the subtropical climate zone, due to a great variety of reflection spectra of vegetation, a selection of the spectral detection bands for reliable identification of dominant coniferous or broadleaved tree species is possible only for specific forestlands where the number of evergreen broadleaved and coniferous tree species is relatively small.

scholarly journals Subglacial Processes at Bondhusbreen, Norway: Preliminary Results

1983 ◽  
Vol 4 ◽  
pp. 91-98 ◽  
Author(s):  
Jon Ove Hagen ◽  
Bjørn Wold ◽  
Olav Liestøl ◽  
Gunnar Østrem ◽  
Johan Ludvig Sollid
Keyword(s):  
Water Pressure ◽  
Water Discharge ◽  
Pressure Sensors ◽  
Hydroelectric Power ◽  
Outlet Glacier ◽  
Running Water ◽  
Order Of Magnitude ◽  
The Difference ◽  
Annual Water Discharge ◽  
Small Channels

Subglacial hydrology, sediment transport, pressure, and temperature have been studied beneath approximately 160 m of ice at Sondhusbreen, an outlet glacier from Folgefonni in south-western Norway.The volume of the mean annual water discharge passing through the study area is about 60x106 m3. Most of this water is diverted into a tunnel system in the rock beneath the glacier and used for hydroelectric power generation. At the beginning of the melt season, this water flows in multiple small channels, but later it collects in one or two main channels. The discharge of eroded material is about 7 600 tonnes a−1. Of this, roughly 90% is transported by running water.Pressure gauges and thermistors were installed at two sites under the glacier. Results from one of the sites indicated that ice can stagnate in some leeward positions, as almost no ice movement was recorded during most of the period of measurement and the pressure distribution was nearly hydrostatic. However, increased water pressure during the summer apparently resulted in the opening of subglacial cavities, adding a local up-glacier component to the flow at this site.At another location, about 20 m up-glacier, non-hydrostatic differential pressures of up to 30 bar were recorded across an artificial dome-shaped obstacle. The flow at this location was more steady, in general, but rather dramatic effects were recorded when a boulder 0.3 m3 in size passed over the obstacle, destroying one of the pressure sensors. This sensor recorded a pressure of 90 bar before failing. The boulder was moving at a speed of about 40 mm d-1, whereas the sliding velocity of the ice was 80 mm d-1. Temperature measurements suggest that the difference in temperature across this obstacle was less than 0.03 deg, or an order of magnitude less than expected. This may mean that water was squeezed out of the ice on the stoss side of the obstacle as suggested by Robin (1976), and thus was not available to warm the lee-side ice by refreezing.

scholarly journals Subglacial Processes at Bondhusbreen, Norway: Preliminary Results

1983 ◽  
Vol 4 ◽  
pp. 91-98 ◽  
Author(s):  
Jon Ove Hagen ◽  
Bjørn Wold ◽  
Olav Liestøl ◽  
Gunnar Østrem ◽  
Johan Ludvig Sollid
Keyword(s):  
Water Pressure ◽  
Water Discharge ◽  
Pressure Sensors ◽  
Hydroelectric Power ◽  
Outlet Glacier ◽  
Running Water ◽  
Order Of Magnitude ◽  
The Difference ◽  
Annual Water Discharge ◽  
Small Channels

Subglacial hydrology, sediment transport, pressure, and temperature have been studied beneath approximately 160 m of ice at Sondhusbreen, an outlet glacier from Folgefonni in south-western Norway.The volume of the mean annual water discharge passing through the study area is about 60x106m3. Most of this water is diverted into a tunnel system in the rock beneath the glacier and used for hydroelectric power generation. At the beginning of the melt season, this water flows in multiple small channels, but later it collects in one or two main channels. The discharge of eroded material is about 7 600 tonnes a−1. Of this, roughly 90% is transported by running water.Pressure gauges and thermistors were installed at two sites under the glacier. Results from one of the sites indicated that ice can stagnate in some leeward positions, as almost no ice movement was recorded during most of the period of measurement and the pressure distribution was nearly hydrostatic. However, increased water pressure during the summer apparently resulted in the opening of subglacial cavities, adding a local up-glacier component to the flow at this site.At another location, about 20 m up-glacier, non-hydrostatic differential pressures of up to 30 bar were recorded across an artificial dome-shaped obstacle. The flow at this location was more steady, in general, but rather dramatic effects were recorded when a boulder 0.3 m3in size passed over the obstacle, destroying one of the pressure sensors. This sensor recorded a pressure of 90 bar before failing. The boulder was moving at a speed of about 40 mm d-1, whereas the sliding velocity of the ice was 80 mm d-1. Temperature measurements suggest that the difference in temperature across this obstacle was less than 0.03 deg, or an order of magnitude less than expected. This may mean that water was squeezed out of the ice on the stoss side of the obstacle as suggested by Robin (1976), and thus was not available to warm the lee-side ice by refreezing.

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