scholarly journals Infrared receptors in pyrophilous (“fire loving”) insects as model for new un-cooled infrared sensors

2011 ◽  
Vol 2 ◽  
pp. 186-197 ◽  
Author(s):  
David Klocke ◽  
Anke Schmitz ◽  
Helmut Soltner ◽  
Herbert Bousack ◽  
Helmut Schmitz
Keyword(s):  
Forest Fires ◽  
Pressure Increase ◽  
Organic Liquids ◽  
Infrared Sensors ◽  
Ir Radiation ◽  
Temperature Changes ◽  
Thermal Expansion Coefficients ◽  
Analytical Formulas ◽  
High Thermal Expansion ◽  
Expansion Coefficients

Beetles of the genus Melanophila and certain flat bugs of the genus Aradus actually approach forest fires. For the detection of fires and of hot surfaces the pyrophilous species of both genera have developed infrared (IR) receptors, which have developed from common hair mechanoreceptors. Thus, this type of insect IR receptor has been termed photomechanic and shows the following two special features: (i) The formation of a complex cuticular sphere consisting of an outer exocuticular shell as well as of a cavernous microfluidic core and (ii) the enclosure of the dendritic tip of the mechanosensitive neuron inside the core in a liquid-filled chamber. Most probably a photomechanic IR sensillum acts as a microfluidic converter of infrared radiation which leads to an increase in internal pressure inside the sphere, which is measured by a mechanosensitive neuron. A simple model for this biological IR sensor is a modified Golay sensor in which the gas has been replaced by a liquid. Here, the absorbed IR radiation results in a pressure increase of the liquid and the deflection of a thin membrane. For the evaluation of this model analytical formulas are presented, which permits the calculation of the pressure increase in the cavity, the deformation of the membrane and the time constant of an artificial leak to compensate ambient temperature changes. Some organic liquids with high thermal expansion coefficients may improve the deflection of the membrane compared to water.

Infrared receptors of pyrophilous jewel beetles as model for new infrared sensors

Sensor Review ◽  
2014 ◽  
Vol 34 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Thilo Kahl ◽  
Herbert Bousack ◽  
Erik S. Schneider ◽  
Helmut Schmitz
Keyword(s):  
Electron Microscopy ◽  
Forest Fires ◽  
Fire Detection ◽  
Pressure Increase ◽  
Organic Liquids ◽  
Infrared Sensors ◽  
Ir Radiation ◽  
Content Type ◽  
Thermal Expansion Coefficients ◽  
Analytical Formulas

Purpose – Early detection of forest fires offers the chance to put the fire out before it gets out of control. The purpose of this paper is to look into nature and to learn how certain insects detect remote forest fires. A small group of highly specialized insects that have been called pyrophilous is attracted by forest fires and approaches fires sometimes from distances of many kilometers. As a unique feature some of these insects are equipped with infrared (IR) receptors, which in case of two species of jewel beetles (family Buprestidae) are used for fire detection. Design/methodology/approach – The paper has investigated the IR receptors of the pyrophilous beetles with various morphological techniques including scanning electron microscopy, transmission electron microscopy, neuroanatomy and the paper also investigated the thermo-/mechanical properties of the IR receptors by nanoindentation. Data were used for subsequent modeling of a biomimetic technical sensor. Finally, a macroscopic prototype was built and tested. Findings – This biological principle was transferred into a new kind of uncooled technical IR receptor. A simple model for this biological IR sensor is a modified Golay sensor in which the gas has been replaced by a liquid. Here, the absorbed IR radiation results in a pressure increase of the liquid and the deflection of a thin membrane. For the evaluation of this model, analytical formulas are presented, which permits the calculation of the pressure increase in the cavity, the deformation of the membrane and the time constant of an artificial leak to compensate ambient temperature changes. Some organic liquids with high thermal expansion coefficients may improve the deflection of the membrane compared to water. Originality/value – Results so far obtained suggest that it seems promising to take the photomechanic IR receptors of pyrophilous jewel beetles as models for the building of new uncooled IR sensors. The beetle receptors have been shaped by evolution since thousands of years and, therefore, can be considered as highly optimized sources of inspiration for new technical sensors suitable for remote fire detection.

Variation of the Expansion Coefficient of Nanofluids With Temperature: A Correction for Conductivity Data

2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Efstathios E. Michaelides
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Conductivity Data ◽  
Volumetric Fraction ◽  
Solid Materials ◽  
Strong Function ◽  
Temperature Changes ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Expansion Coefficients

The two constituent phases of the nanofluids have thermal expansion coefficients that are significantly different. Moreover, the variability of the thermal expansion coefficients of fluids with temperature is significantly higher than that of solid materials. The mismatch of the thermal expansion coefficients creates changes of the volumetric fraction of solids with temperature changes. The changes can be significant with fluids that have high thermal expansion coefficients, such as refrigerants and fluids that operate close to their critical points. Since the thermal conductivity of nanofluids is a very strong function of the volumetric fraction of the nanoparticles, these changes of the volumetric fraction may cause significant effects on the thermal conductivity of the nanofluids, which must be accounted for in any design process.

Novel Silicon-Elastomers for Advanced Soft Lithography

2006 ◽  
Vol 947 ◽  
Author(s):  
Kyung Choi
Keyword(s):  
Thermal Expansion ◽  
High Resolution ◽  
Soft Lithography ◽  
Materials Properties ◽  
Nano Scale ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Expansion Coefficients

ABSTRACTHigh resolution pattern transfers in the nano-scale regime have been considerable challenges in ‘soft lithography’ to achieve nanodevices with enhanced performances. In this technology, the resolution of pattern integrations is significantly rely on the materials' properties of polydimethylsiloxane (PDMS) stamps. Since commercial PDMS stamps have shown limitations in nano-scale resolution soft lithography due to their low physical toughness and high thermal expansion coefficients, we developed stiffer, photocured PDMS silicon elastomers designed, specifically for nano-sized soft lithography and photopatternable nanofabrications.

Preparation and Characterization of Thermally Compatible Leucite-Reinforced Dental Ceramics

2011 ◽  
Vol 308-310 ◽  
pp. 311-314
Author(s):  
Jin Wen ◽  
Shu Zhen Sun
Keyword(s):  
Thermal Expansion ◽  
Dental Ceramics ◽  
Dental Porcelain ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Coprecipitation Technique ◽  
Thermal Compatibility ◽  
The Common ◽  
Expansion Coefficients

The high average thermal expansion required for thermal compatibility of dental porcelain with their substrate alloy is supplied by the mineral leucite (KAlSi2O6). In the research, the high thermal expansion coefficients phase leucite was prepared by coprecipitation technique. Three materials with formulae of K2O∶Al2O3∶SiO2= 1∶1∶x ( x=1.4, 2.0, 4.0 ) were investigated for differences in phase, thermal expansion. Unstoichiometric composition where K2O and Al2O3were added properly is advantage to leucite obtained. Coprecipitation processing produced fine leucite powder that would sinter at 1300°C, this temperature is about 200°C lower than of melting method. The average thermal expansion coefficients of leucite is 22.7×10-6/°Cfrom room temperature to 620°C,which is higher than the common porcelain. Changing in the leucite content of dental porcelain would results from thermal expansion coefficients of porcelain variation, which could be responsible for changes in porcelain-metal thermal compatibility.

A New Application of Bimetallic Thin Film

2013 ◽  
Vol 661 ◽  
pp. 128-131
Author(s):  
Xiao Yu Yang ◽  
Wei Zhou
Keyword(s):  
Thin Film ◽  
Temperature Compensation ◽  
Fem Simulation ◽  
Frequency Stability ◽  
Crystal Plate ◽  
Crystal Oscillator ◽  
Temperature Changes ◽  
Thermal Expansion Coefficients ◽  
Element Simulation ◽  
Expansion Coefficients

To perform the temperature compensation, a bimetallic thin film with different thermal expansion coefficients is deposited on the surface of the crystal plate. The thermal stress generated in the crystal and the thin film will cancel each other when temperature changes, thus improve the frequency stability of the crystal oscillator. In this paper, a finite element simulation was carried out for the crystal plate with bimetal, and then an experiment was performed to verify the FEM simulation results. The result shows that this approach achieves good temperature - frequency characteristics and reduces the frequency shift of crystal oscillator.

Intermetallic M Pt3 (M = Ti, Zr, Hf): Elastic, electronic, optical and thermal properties

2019 ◽  
Vol 33 (18) ◽  
pp. 1950189 ◽  
Author(s):  
S. K. Mitro ◽  
M. A. Rahman ◽  
F. Parvin ◽  
A. K. M. A. Islam
Keyword(s):  
Thermal Properties ◽  
Elevated Temperatures ◽  
Visible Region ◽  
Debye Model ◽  
Mechanical And Thermal Properties ◽  
Electronic Band ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Expansion Coefficients ◽  
Electronic Band Structures

In this study, the structural and unexplored elastic, electronic, optical and thermal properties of Pt-based alloys MPt3 (M = Ti, Hf) and only optical and thermal properties of ZrPt3 are subjected to investigation using the method of the first principles. The results of pressure dependence of mechanical and thermal properties are discussed. The electronic band structures and density of state data show metallic conductivity for all the compounds. The main contribution at Fermi level comes from Ti 3d and Zr 4d (for TiPt3 and ZrPt[Formula: see text] and Pt 5d (for HfPt[Formula: see text] orbitals. The materials’ optical reflectivity values, relatively high in the IR-visible-UV regions, range from [Formula: see text]62% to 72% in the visible region which show better performance values in comparison to those of some representative materials PtAl2, AuAl2 and GdX3 (X = In, Sn, Tl, Pb). The unexplored thermal behaviors are also investigated via quasi-harmonic Debye model at T = 0 and P = 0 as well as at elevated temperatures and pressures. In addition, when used as bonding materials, studied intermetallics with moderately high thermal expansion coefficients can match other substrates. This coupled with the estimated thermal conductivities (k[Formula: see text]) compared to several other species indicate that the intermetallics can be used in applications, such as thermal barrier coatings (TBC). This study has thus indicated possible alternative candidates for high-temperature applications which would initiate further research and development on the intermetallics under study.

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

Influence of Magnetoelastic Anisotropy on Properties of Nanostructured Microwires

2013 ◽  
Vol 646 ◽  
pp. 59-66 ◽  
Author(s):  
Arcady Zhukov ◽  
Margarita Churyukanova ◽  
Lorena Gonzalez-Legarreta ◽  
Ahmed Talaat ◽  
Valentina Zhukova ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Hysteresis Loops ◽  
Magnetic Behaviour ◽  
Soft Magnetic ◽  
Magnetoelastic Anisotropy ◽  
Thermal Expansion Coefficients ◽  
Magnetoelastic Energy ◽  
Expansion Coefficients ◽  
The Difference ◽  
Magneto Resistance

We studied the effect ofthe magnetoelastic ansitropy on properties of nanostructured glass-coated microwires with soft magnetic behaviour (Finemet-type microwires of Fe70.8Cu1Nb3.1Si14.5B10.6, Fe71.8Cu1Nb3.1Si15B9.1 and Fe73.8Cu1Nb3.1Si13B9.1 compositions) and with granular structure (Cu based Co-Cu microwires). The magnetoelastic energy originated from the difference in thermal expansion coefficients of the glass and metallic alloy during the microwires fabrication, affected the hysteresis loops, coercivity and heat capacity of Finemet-type microwires. Hysteresis loops of all as-prepared microwires showed rectangular shape, typical for Fe-rich microwires. As expected, coercivity, HC, of as-prepared microwires increases with decreasing of the ratio ρ defined as the ratio between the metallic nucleus diameter, d to total microwire diameter, D. On the other hand we observed change of heat capacity in microwires with different ratio ρ. In the case of Co-Cu microwires ρ- ratio affected the structure and the giant magneto-resistance of obtained microwires.

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