scholarly journals Analysis of Thin Film Fire Sensors

1984 ◽  
Vol 11 (3) ◽  
pp. 209-214
Author(s):  
G. Zentai ◽  
Zs. Illyefalvi-Vitéz
Keyword(s):  
Thin Film ◽  
Time Constant ◽  
Small Volume ◽  
Temperature Sensitive ◽  
Thin Glass ◽  
Time Constants ◽  
Industrial Buildings ◽  
The Difference ◽  
Two Temperature ◽  
Resistance Difference

The detection of fire in mines, industrial buildings, ships etc. is an important problem from both the economical and life-protecting aspects. The fire could be detected in several ways, e.g. by the measurement of flame-radiation, heat, pressure, temperature, the aerosols, the gases etc.The Department of Electronic Technology has developed a fire sensor which detects the rate of the increase of temperature. The fire sensor consists of two temperature sensitive resistors with different time-constants. If the increase of temperature in consequence of the fire is fast, the difference between the resistance of the temperature sensors is high, while a slow change in temperature causes only small differences. By connecting the temperature sensitive sensors into a bridge, the resistance difference can be easily detected.The temperature sensitive resistors are realized by thin film technology using platinum or nickel film on a thin glass or ceramic substrate. Because of the large surface and small volume of the resistor, its time-constant originally is very low but the time-constant could be easily increased by increasing the volume of the resistor. The present paper gives a detailed description of the analysis and the measurement of the temperature sensitive resistors with different time-constants. The technology of the films is also discussed.

Surface Microstructure Evolution Upon Silicidation of Ni(Pt) and the Different Responses to Metal Etch

2013 ◽  
Author(s):  
Wentao Qin ◽  
Dorai Iyer ◽  
Jim Morgan ◽  
Carroll Casteel ◽  
Robert Watkins ◽  
...  
Keyword(s):  
Thin Film ◽  
Oxide Film ◽  
Microstructure Evolution ◽  
Depth Profiling ◽  
Surface Microstructure ◽  
The Difference ◽  
Surface Microstructures ◽  
Pt Films

Abstract Ni(5 at.%Pt ) films were silicided at a temperature below 400 °C and at 550 °C. The two silicidation temperatures had produced different responses to the subsequent metal etch. Catastrophic removal of the silicide was seen with the low silicidation temperature, while the desired etch selectivity was achieved with the high silicidation temperature. The surface microstructures developed were characterized with TEM and Auger depth profiling. The data correlate with both silicidation temperatures and ultimately the difference in the response to the metal etch. With the high silicidation temperature, there existed a thin Si-oxide film that was close to the surface and embedded with particles which contain metals. This thin film is expected to contribute significantly to the desired etch selectivity. The formation of this layer is interpreted thermodynamically.

scholarly journals Individual motion perception parameters and motion sickness frequency sensitivity in fore-aft motion

2021 ◽  
Author(s):  
Tugrul Irmak ◽  
Ksander N. de Winkel ◽  
Daan M. Pool ◽  
Heinrich H. Bülthoff ◽  
Riender Happee
Keyword(s):  
Motion Sickness ◽  
Motion Perception ◽  
Time Constant ◽  
Storage Time ◽  
Velocity Storage ◽  
Strong Positive Correlation ◽  
Subjective Vertical ◽  
Time Constants ◽  
Frequency Sensitivity ◽  
Observer Model

AbstractPrevious literature suggests a relationship between individual characteristics of motion perception and the peak frequency of motion sickness sensitivity. Here, we used well-established paradigms to relate motion perception and motion sickness on an individual level. We recruited 23 participants to complete a two-part experiment. In the first part, we determined individual velocity storage time constants from perceived rotation in response to Earth Vertical Axis Rotation (EVAR) and subjective vertical time constants from perceived tilt in response to centrifugation. The cross-over frequency for resolution of the gravito-inertial ambiguity was derived from our data using the Multi Sensory Observer Model (MSOM). In the second part of the experiment, we determined individual motion sickness frequency responses. Participants were exposed to 30-minute sinusoidal fore-aft motions at frequencies of 0.15, 0.2, 0.3, 0.4 and 0.5 Hz, with a peak amplitude of 2 m/s2 in five separate sessions, approximately 1 week apart. Sickness responses were recorded using both the MIsery SCale (MISC) with 30 s intervals, and the Motion Sickness Assessment Questionnaire (MSAQ) at the end of the motion exposure. The average velocity storage and subjective vertical time constants were 17.2 s (STD = 6.8 s) and 9.2 s (STD = 7.17 s). The average cross-over frequency was 0.21 Hz (STD = 0.10 Hz). At the group level, there was no significant effect of frequency on motion sickness. However, considerable individual variability was observed in frequency sensitivities, with some participants being particularly sensitive to the lowest frequencies, whereas others were most sensitive to intermediate or higher frequencies. The frequency of peak sensitivity did not correlate with the velocity storage time constant (r = 0.32, p = 0.26) or the subjective vertical time constant (r = − 0.37, p = 0.29). Our prediction of a significant correlation between cross-over frequency and frequency sensitivity was not confirmed (r = 0.26, p = 0.44). However, we did observe a strong positive correlation between the subjective vertical time constant and general motion sickness sensitivity (r = 0.74, p = 0.0006). We conclude that frequency sensitivity is best considered a property unique to the individual. This has important consequences for existing models of motion sickness, which were fitted to group averaged sensitivities. The correlation between the subjective vertical time constant and motion sickness sensitivity supports the importance of verticality perception during exposure to translational sickness stimuli.

A Model of Wheat Grain Growth and Its Applications to Different Temperature and Carbon Dioxide Levels

1995 ◽  
Vol 22 (5) ◽  
pp. 843 ◽  
Author(s):  
YP Wang ◽  
RM Gifford
Keyword(s):  
Growth Rate ◽  
Grain Growth ◽  
Temperature Response ◽  
Rate Sensitivity ◽  
Temperature Sensitive ◽  
Potential Growth ◽  
Carbon Supply ◽  
The Difference ◽  
Carbon Dioxide Levels ◽  
Kernel Growth

Kernel growth after anthesis is simulated as a function of the potential kernel growth rate, current photosynthate production and mobilisation of stored reserves. The potential growth rate of the kernel is simulated as two temperature-sensitive processes, cell production and cell growth. The difference between the potential and actual growth rates of the kernel depends on the carbon supply to the free space of the kernel endosperm, while the carbon supply is itself affected by the actual kernel growth rate. Sensitivity analysis showed that the growth rate of the grain per plant is most sensitive to the potential growth rate of the kernel and number of kernels per plant. This model is able to simulate the observed rates of grain growth and leaf senescence from anthesis to physiological maturity for wheat plants grown in two CO2 concentrations. The simulated temperature response of grain growth agrees well with the experimenal observations.

Effect of Film Thickness on Fatigue Strength of TiAl Alloy Coated with TiAlN Film at Elevated Temperature

2005 ◽  
Vol 297-300 ◽  
pp. 1446-1451 ◽  
Author(s):  
Takeshi Kasuya ◽  
Hideto Suzuki
Keyword(s):  
Thin Film ◽  
Fatigue Strength ◽  
Film Thickness ◽  
Thick Film ◽  
Physical Vapor Deposition ◽  
Tial Alloy ◽  
Testing Machine ◽  
Intermetallic Alloy ◽  
Fracture Control ◽  
The Difference

The fatigue strength of TiAl intermetallic alloy coated with TiAlN film was studied in vacuum at 1073K using a SEM-servo testing machine. In addition, three kinds of TiAlN films were given by physical vapor deposition (1, 3, and 10μ m). The fatigue strength of 3μ m was highest. Also, the fatigue strength of 1μ m was lowest. From this result, existence of optimum film thickness was suggested because the difference of fatigue strength arose in each film thickness. The justification for existence of optimum film thickness is competition of 45-degree crack and 90-degree crack. The 45-degree crack is phenomenon seen in the thin film (1μ m), and is caused by plastic deformation of TiAl substrate. The 45-degree crack is the factor of the fatigue strength fall by the side of thin film. In contrast, the 90-degree crack is phenomenon in the thick film (10μ m), and is caused as result of reaction against load to film. The 90-degree crack is the factor of the fatigue strength fall by the side of thick film. In conclusion, the optimum film thickness can perform meso fracture control, and improves fatigue strength.

Measurements of Residual Stress in the Layers of Thin Film Micro-Gas Sensors

2000 ◽  
Vol 657 ◽  
Author(s):  
Youngman Kim ◽  
Sung-Ho Choo
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Micro Gas Sensor ◽  
Thin Film Layer ◽  
Film Layer ◽  
The Difference ◽  
Stress States

ABSTRACTThe mechanical properties of thin film materials are known to be different from those of bulk materials, which are generally overlooked in practice. The difference in mechanical properties can be misleading in the estimation of residual stress states in micro-gas sensors with multi-layer structures during manufacturing and in service.In this study the residual stress of each film layer in a micro-gas sensor was measured according to the five difference sets of film stacking structure used for the sensor. The Pt thin film layer was found to have the highest tensile residual stress, which may affect the reliability of the micro-gas sensor. For the Pt layer the changes in residual stress were measured as a function of processing variables and thermal cycling.

Why is the perceptual octave stretched? An account based on mismatched time constants within the auditory brainstem

2021 ◽  
Author(s):  
Alain de Cheveigné
Keyword(s):  
Time Constant ◽  
Auditory Brainstem ◽  
The Other ◽  
Inhibitory Synapses ◽  
Coincidence Counting ◽  
Time Constants ◽  
Direct Pathway ◽  
Lower Tone ◽  
Excitatory And Inhibitory Synapses

This paper suggests an explanation for listener’s greater tolerance to positive than negative mistuning of the higher tone within an octave pair. It hypothesizes a neu- ral circuit tuned to cancel the lower tone, that also cancels the higher tone if that tone is in tune. Imperfect cancellation is the cue to mistuning of the octave. The circuit involves two pathways, one delayed with respect to the other, that feed a coincidence-counting neuron via excitatory and inhibitory synapses. A mismatch between the time constants of these two synapses results in an asymmetry in sen- sitivity to mismatch. Specifically, if the time constant of the delayed pathway is greater than that of the direct pathway, there is a greater tolerance to positive than to negative mistuning, which can lead to a perceptual“stretch” of the octave. The model is applicable to both harmonic and – with qualification – melodic oc- taves. The paper describes the model and reviews the evidence from auditory psychophysics and physiology in favor – or against – it.

scholarly journals MnO2 thin film electrodes for enhanced reliability of thin glass capacitors

2018 ◽  
Vol 101 (12) ◽  
pp. 5870-5870
Author(s):  
Betul Akkopru‐Akgun ◽  
Susan Trolier‐McKinstry ◽  
Michael T. Lanagan
Keyword(s):  
Thin Film ◽  
Thin Glass ◽  
Thin Film Electrodes
Sign in / Sign up

Export Citation Format

Share Document