Complementary domain pyroelectric detectors with reduced sensitivity to mechanical vibrations and temperature changes

1975 ◽  
Vol 27 (12) ◽  
pp. 639-641 ◽  
Author(s):  
N. E. Byer ◽  
S. E. Stokowski ◽  
J. D. Venables
Keyword(s):  
Mechanical Vibrations ◽  
Temperature Changes ◽  
Pyroelectric Detectors ◽  
Complementary Domain

scholarly journals Intensity Modulated Photothermal Measurements of NO2 with a Compact Fiber-Coupled Fabry–Pérot Interferometer

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3341 ◽  
Author(s):  
Philipp Breitegger ◽  
Benjamin Lang ◽  
Alexander Bergmann
Keyword(s):  
Nitrogen Dioxide ◽  
Health Effects ◽  
Response Times ◽  
Fast Response ◽  
Reliable Measurement ◽  
Mechanical Vibrations ◽  
Temperature Changes ◽  
Adverse Health Effects ◽  
Intensity Modulated ◽  
Fabry Perot

Sensors for the reliable measurement of nitrogen dioxide concentrations are of high interest due the adverse health effects of this pollutant. This work employs photothermal spectroscopy to measure nitrogen dioxide concentrations at the parts per billion level. Absorption induced temperature changes are detected by means of a fiber-coupled Fabry–Pérot interferometer. The small size of the interferometer enables small detection volumes, paving the way for miniaturized sensing concepts as well as fast response times, demonstrated down to 3 s. A normalized noise equivalent absorption of 7.5 × 10 − 8 cm−1W/ Hz is achieved. Additionally, due to the rigid structure of the interferometer, the sensitivity to mechanical vibrations is shown to be minor.

Downhole Fluid Analysis During Wellbore Sampling at High Temperatures Using a Pyroelectric Array Spectrometer

2021 ◽  
Vol 73 (05) ◽  
pp. 41-43
Author(s):  
Emeakpo Ojonah
Keyword(s):  
High Temperature ◽  
Incident Radiation ◽  
Ferroelectric Materials ◽  
Infrared Light ◽  
Pyroelectric Detector ◽  
Temperature Changes ◽  
Fluid Identification ◽  
Fluid Analysis ◽  
Pyroelectric Detectors ◽  
Contamination Levels

While the world is transitioning into a greener and less-carbon-rich energy source, the fact remains that there is a growing need for exploration and production of hydrocarbons in previously untapped resources. These frontier reservoirs, while extremely hot, are prolific and make the footprint of the exploration activity much smaller than shallower drilling, which would require many more wells to deliver the same amount of hydrocarbon. These frontier wells, classified as high-pressure/high-temperature (HP/HT) wells, are defined as wells with reservoir or bottomhole temperatures higher than 300°F and which require pressure-control equipment with a rating above 10,000 psi. HP/HT wells can be found offshore in the North Sea and Gulf of Mexico, or on land—as seen recently in the Gongola Basin. Fluid identification, which is a critical process in fluid sampling, continues to be a challenge in temperatures above 350°F. At temperatures up to 450°F, fluid identification is currently achieved by bubblepoint and compressibility measurements, which cannot quantitatively measure contamination levels of the subject sample fluid. A possible solution to this problem would involve using pyroelectric detectors in the process of estimating a property of a downhole fluid. The method and apparatus in this approach involves exposing a fluid to modulated light downhole and sensing changes in the intensity of infrared radiation from the downhole fluid, to estimate the level of filtrate contamination and other properties. The pyroelectric detector senses changes in the intensity of light by con-verting the transient changes in temperature of its detector and performs the spectroscopic fluid analysis by optically filtering the light allowed to impinge on it, converting the changes in temperature of the pyroelectric detector to a signal which can then be used to estimate the property of the downhole fluid. If successfully implemented, this would enable the wireline-logging industry to develop an optical fluid analyser capable of quantitatively measuring fluid contamination levels in high-temperature (greater than 300°F) environments. Theory Pyroelectric infrared detectors (PIR) convert the changes in incoming infrared light to electric signals. Pyroelectric materials are characterized by having spontaneous electric polarization, which is altered by temperature changes as infrared light illuminates the elements. Pyroelectric detectors (Fig. 1) are thermal detectors, meaning they produce a signal in response to a change in their temperature. Below a case temperature (Tc) known as the Curie point, ferroelectric materials such as lithium tantalate exhibit a large spontaneous electrical polarization. If the temperature of such a material is altered, for example by incident radiation, the polarization changes. This change in polarization may be observed as an electrical signal when electrodes are placed on opposite faces of a thin slice of the material to form a capacitor. When the polarization changes, if the external impedance is comparatively high, the charges induced in the electrodes can be made to produce a voltage across the slice. The sensor will only produce an electrical output signal when the temperature changes; that is, when the level of incident-radiation changes.

Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions

1993 ◽  
Vol 51 ◽  
pp. 876-877
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Microstructural Characterization ◽  
Building Blocks ◽  
Quantitative Information ◽  
Physical Models ◽  
Specimen Preparation ◽  
Time Resolved ◽  
Temperature Changes ◽  
Temperature And Humidity ◽  
Microstructured Fluids ◽  
Air Streams

To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

Application of pyrometer and standard sample to determine surface temperature of studied materials

2019 ◽  
pp. 9-13
Author(s):  
V.Ya. Mendeleyev ◽  
V.A. Petrov ◽  
A.V. Yashin ◽  
A.I. Vangonen ◽  
O.K. Taganov
Keyword(s):  
Composite Material ◽  
Surface Temperature ◽  
Relative Error ◽  
Wavelength Range ◽  
Standard Sample ◽  
A Priori ◽  
Temperature Changes ◽  
Surface Temperatures ◽  
Relative Errors ◽  
Normal Emissivity

Determining the surface temperature of materials with unknown emissivity is studied. A method for determining the surface temperature using a standard sample of average spectral normal emissivity in the wavelength range of 1,65–1,80 μm and an industrially produced Metis M322 pyrometer operating in the same wavelength range. The surface temperature of studied samples of the composite material and platinum was determined experimentally from the temperature of a standard sample located on the studied surfaces. The relative error in determining the surface temperature of the studied materials, introduced by the proposed method, was calculated taking into account the temperatures of the platinum and the composite material, determined from the temperature of the standard sample located on the studied surfaces, and from the temperature of the studied surfaces in the absence of the standard sample. The relative errors thus obtained did not exceed 1,7 % for the composite material and 0,5% for the platinum at surface temperatures of about 973 K. It was also found that: the inaccuracy of a priori data on the emissivity of the standard sample in the range (–0,01; 0,01) relative to the average emissivity increases the relative error in determining the temperature of the composite material by 0,68 %, and the installation of a standard sample on the studied materials leads to temperature changes on the periphery of the surface not exceeding 0,47 % for composite material and 0,05 % for platinum.

Late Holocene precipitation and temperature changes in Northern Europe linked with North Atlantic forcing

2015 ◽  
Vol 66 (1) ◽  
pp. 37-48 ◽  
Author(s):  
TP Luoto ◽  
L Nevalainen
Keyword(s):  
North Atlantic ◽  
Late Holocene ◽  
Northern Europe ◽  
Temperature Changes ◽  
Precipitation And Temperature

Ecological niche modelling of cold-water corals in the Southern Ocean (N Antarctic), present distribution and future projections due to temperature changes

2019 ◽  
Vol 628 ◽  
pp. 73-93
Author(s):  
S Chaabani ◽  
PJ López-González ◽  
P Casado-Amezua ◽  
H Pehlke ◽  
L Weber ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Ecological Niche ◽  
Cold Water ◽  
Ecological Niche Modelling ◽  
Niche Modelling ◽  
Future Projections ◽  
Temperature Changes ◽  
Present Distribution

Measuring Facial Skin Temperature Changes Caused by Mental Work-Load with Infrared Thermography

2016 ◽  
Vol 136 (11) ◽  
pp. 1581-1585 ◽  
Author(s):  
Tota Mizuno ◽  
Takeru Sakai ◽  
Shunsuke Kawazura ◽  
Hirotoshi Asano ◽  
Kota Akehi ◽  
...  
Keyword(s):  
Skin Temperature ◽  
Infrared Thermography ◽  
Work Load ◽  
Facial Skin ◽  
Mental Work ◽  
Temperature Changes ◽  
Mental Work Load

TEMPERATURE CHANGES FOR METHANE HYDRATE DISSOCIATION IN DIFFERENT CLASS DEPOSITS BY DEPRESSURIZATION

2018 ◽  
Author(s):  
Mingjun Yang ◽  
Yi Gao ◽  
Hang Zhou ◽  
Bingbing Chen ◽  
Yongchen Song
Keyword(s):  
Methane Hydrate ◽  
Hydrate Dissociation ◽  
Temperature Changes

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

RESEARCH RESPONSE QUENCHER MECHANICAL VIBRATIONS BY THE FORMULA Of CARDANO

2013 ◽  
Vol 33 (0) ◽  
pp. 181-185
Author(s):  
М. І. Ігнатишин ◽  
І. Д. Рубіш
Keyword(s):  
Mechanical Vibrations
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