Light-driven dynamic surface wrinkles for adaptive visible camouflage

2021 ◽  
Vol 118 (48) ◽  
pp. e2114345118
Author(s):  
Tianjiao Ma ◽  
Jing Bai ◽  
Tiantian Li ◽  
Shuai Chen ◽  
Xiaodong Ma ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Dynamic Characteristics ◽  
Optical Signal ◽  
Photothermal Effect ◽  
Dynamic Surface ◽  
Scattering Of Light ◽  
On Demand ◽  
The Military ◽  
Demand Control

Camouflage is widespread in nature, engineering, and the military. Dynamic surface wrinkles enable a material the on-demand control of the reflected optical signal and may provide an alternative to achieve adaptive camouflage. Here, we demonstrate a feasible strategy for adaptive visible camouflage based on light-driven dynamic surface wrinkles using a bilayer system comprising an anthracene-containing copolymer (PAN) and pigment-containing poly (dimethylsiloxane) (pigment-PDMS). In this system, the photothermal effect–induced thermal expansion of pigment-PDMS could eliminate the wrinkles. The multiwavelength light–driven dynamic surface wrinkles could tune the scattering of light and the visibility of the PAN film interference color. Consequently, the color captured by the observer could switch between the exposure state that is distinguished from the background and the camouflage state that is similar to the surroundings. The bilayer wrinkling system toward adaptive visible camouflage is simple to configure, easy to operate, versatile, and exhibits in situ dynamic characteristics without any external sensors and extra stimuli.

Wątek składania ofiar w dekoracji budowli sakralnych Dura Europos

Vox Patrum ◽  
2015 ◽  
Vol 64 ◽  
pp. 393-402
Author(s):  
Ilona Skupińska-Løvset
Keyword(s):  
Roman Empire ◽  
Late Antiquity ◽  
Archaeological Research ◽  
Dominant Form ◽  
Xxth Century ◽  
Desert Sand ◽  
Military Camp ◽  
The Military

Dura Europos, or as proposed today Europos Dura, was a fortified settlement on the border between the Roman Empire and the East. The archeological dis­coveries reflected the character of the settlement – the fortified agglomeration grouped at the military camp. After its fall Europos Dura was covered by desert sand only to be discovered in the XXth century. Archaeological research has dis­closed documentation of its multicultural character. This paper points to the fact of coexistence of various religions in late antiquity Europos Dura. Paintings and sculptures discovered in situ indicate that scene of offering was a favorite subject in the sacral art of Europos Dura, independent of religion. The ceremony of in­cense burning constitutes the dominant form of offering regarding visualizations of this important ceremony.

scholarly journals Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4021
Author(s):  
Andrés Esteban Cerón Cerón Cortés ◽  
Anja Dosen ◽  
Victoria L. Blair ◽  
Michel B. Johnson ◽  
Mary Anne White ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Monoclinic Phase ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

scholarly journals Thermal expansion of La-based BMG studied by in situ high-energy X-ray diffraction

2010 ◽  
Vol 504 ◽  
pp. S155-S158 ◽  
Author(s):  
J. Bednarcik ◽  
C. Curfs ◽  
M. Sikorski ◽  
H. Franz ◽  
J.Z. Jiang
Keyword(s):  
Thermal Expansion ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Isobaric Thermal Expansion and Isothermal Compression of Powdered NiFe Based Alloys Studied by In-Situ EDXRD

2014 ◽  
Vol 126 (1) ◽  
pp. 128-129
Author(s):  
D. Olekšáková ◽  
J. Füzer ◽  
P. Kollár ◽  
J. Bednarčík ◽  
C. Lathe
Keyword(s):  
Thermal Expansion ◽  
Isothermal Compression ◽  
Isobaric Thermal Expansion

The retrograde tunnel: a method for the fixation of central venous catheters in the military environment

1991 ◽  
Vol 77 (2) ◽  
pp. 75-77
Author(s):  
R. A. Wheeler ◽  
T. J. W. Spalding ◽  
J. A. Thomas ◽  
G. A. Carss
Keyword(s):  
Central Venous Line ◽  
Central Venous Catheters ◽  
Patient Transfer ◽  
Central Venous ◽  
Medical Facilities ◽  
Subcutaneous Tunnel ◽  
Paediatric Practice ◽  
The Military

AbstractCentral venous catheters (CVCs) are prone to accidental removal during patient transportation. Of the casualties who require transfer between medical facilities, those with CVC in situ require additional vigilance to prevent loss of the CVC, which continues to occur despite various methods of fixation. The fashioning of a subcutaneous tunnel has become an integral part of the placement of central venous catheters. Several methods have been described, but the long-term CVCs in paediatric practice pose special problems, particularly that of the patients continually testing the CVCs fixation. Using a new polyurethane CVC, a retrograde tunnelling technique has been developed which affords immediate and secure fixation. We propose that this CVC, together with the technique of retrograde tunnelling, is the solution to inadvertent central venous line removal during patient transfer.

Enhanced Negative Thermal Expansion Property Deduced by the Breaks of Superstructure

2021 ◽  
Vol 13 (4) ◽  
pp. 556-562
Author(s):  
Niu Zhang ◽  
Ming-Yi Wu ◽  
Ya-Ming Liu ◽  
Meng-Jie Yang ◽  
Ming-Ju Chao ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Wide Temperature Range ◽  
Potential Application ◽  
Negative Thermal Expansion ◽  
Thermal Expansion Property ◽  
Expansion Property ◽  
Good Potential ◽  
Nested Structure

The HfV2O7/HfMo2O8 composite were prepared in situ. The phase, structure and thermal expansion property were analyzed. The results indicate the composite consist of cubic HfV2O7 and hexagonal HfMo2O8. The two types of structures were coexisted and mixed uniformly, and interacted with each other. The mutual nested structure suppressed the formation of 3×3×3 superstructure in HfV2O7 (RT) introduced by the reaction in situ. The promoted coupled rotation of quasi-rigid polyhedron units could enhance the negative thermal expansion (NTE) property. The HfV2O7/HfMo2O8 composite exhibits excellent NTE property from 250 to 673 K (at least) with CTE -3.09 × 10-6 K-1. The good NTE property and thermal stability over a wide temperature range, especially near the RT range, bring a good potential application in designing zero thermal expansion materials.

scholarly journals Adhesive-Free Bonding of Monolithic Sapphire for Pressure Sensing in Extreme Environments

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2712 ◽  
Author(s):  
Jihaeng Yi
Keyword(s):  
Room Temperature ◽  
Extreme Environments ◽  
Optical Signal ◽  
Harsh Environments ◽  
Free Space Optics ◽  
Pressure Sensing ◽  
Space Optics ◽  
Fabry Perot ◽  
Deflection Theory

This paper presents a monolithic sapphire pressure sensor that is constructed from two commercially available sapphire wafers through a combination of reactive-ion etching and wafer bonding. A Fabry–Perot (FP) cavity is sealed fully between the adhesive-free bonded sapphire wafers and thus acts as a pressure transducer. A combination of standard silica fiber, bonded sapphire wafers and free-space optics is proposed to couple the optical signal to the FP cavity of the sensor. The pressure in the FP cavity is measured by applying both white-light interferometry and diaphragm deflection theory over a range of 0.03 to 3.45 MPa at room temperature. With an all-sapphire configuration, the adhesive-free bonded sapphire sensor is expected to be suitable for in-situ pressure measurements in extreme harsh environments.

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