An engineer's introduction to mechanophores

Soft Matter ◽  
2020 ◽  
Vol 16 (27) ◽  
pp. 6230-6252 ◽  
Author(s):  
Naomi Deneke ◽  
Mitchell L. Rencheck ◽  
Chelsea S. Davis
Keyword(s):  
Polymeric Materials ◽  
Stress Sensors ◽  
Material Systems ◽  
As Stress ◽  
Scientific Advances

Mechanophores are force-responsive molecules that have the potential to serve as stress sensors in various material systems. This review discusses recent scientific advances and critical challenges facing engineers regarding implementation of mechanophores in polymeric materials.

Precursors of thymic peptides as stress sensors

2020 ◽  
Vol 20 (12) ◽  
pp. 1461-1475 ◽  
Author(s):  
Sergey Lunin ◽  
Maxim Khrenov ◽  
Olga Glushkova ◽  
Svetlana Parfenyuk ◽  
Tatyana Novoselova ◽  
...  
Keyword(s):  
Stress Sensors ◽  
Thymic Peptides ◽  
As Stress

Large Area Mems: Materials Issues and Applications

2001 ◽  
Vol 685 ◽  
Author(s):  
J.H. Daniel ◽  
R.A. Street ◽  
M. Teepe ◽  
S.E. Ready ◽  
J. Ho ◽  
...  
Keyword(s):  
Polymeric Materials ◽  
Maximum Size ◽  
Image Sensors ◽  
Image Resolution ◽  
Micro Machining ◽  
Mems Devices ◽  
Fabrication Technology ◽  
Large Area ◽  
Mems Fabrication ◽  
As Stress

AbstractConventional MEMS devices are based on silicon micro-machining and their maximum size is limited by the wafer. In contrast, we are exploring micro-machining for large area applications on substrates such as glass using polymeric materials. Our research is focused on the photopolymer SU-8, and we apply the MEMS fabrication technology to large area image sensors and displays. There are many challenges concerning the materials and processes, since large area compatibility is essential and integration with large area electronics may be required. The adhesion of SU-8 to the underlying layers as well as stress in the SU-8 are important issues and surface treatments have been investigated. Two applications of SU-8 MEMS are discussed to illustrate large area applications:. First, in the fabrication of an X-ray imager, high aspect ratio SU-8 walls form a micro-patterned phosphor screen to increase the image resolution. Second, a similar approach of patterning SU-8 into arrays of micro-cells is applied to an electrophoretic display.

scholarly journals Dielectric and Electrical Properties of WS2 Nanotubes/Epoxy Composites and Their Use for Stress Monitoring of Structures

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
A. Sedova ◽  
S. Khodorov ◽  
D. Ehre ◽  
B. Achrai ◽  
H. D. Wagner ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Epoxy Composites ◽  
Electrical Characteristics ◽  
Structural Components ◽  
Stress Monitoring ◽  
Strain Measurements ◽  
Three Point Bending ◽  
Stress Sensors ◽  
Monitoring Applications ◽  
As Stress

The dielectric and electrical characteristics of the semiconductive WS2 nanotubes/epoxy composites were studied as a function of the nanotubes concentration and the pressure applied during their molding. In addition, the ability of WS2 nanotubes to serve as stress sensors in epoxy based nanocomposites, for health-monitoring applications, was studied. The nanocomposite elements were loaded in three-point bending configuration. The direct current was monitored simultaneously with stress-strain measurements. It was found that, in nanocomposites, above the percolation concentrations of the nanotubes, the electrical conductivity increases considerably with the applied load and hence WS2 nanotubes can be potentially used as sensors for health monitoring of structural components.

Membranes as stress sensors fine-tune the stress protein expression

2008 ◽  
Vol 154 ◽  
pp. S18
Author(s):  
Laszlo Vigh ◽  
Zsolt Torok ◽  
Gabor Balogh ◽  
Eniko Nagy ◽  
Imre Gombos ◽  
...  
Keyword(s):  
Protein Expression ◽  
Stress Protein ◽  
Stress Sensors ◽  
As Stress ◽  
Fine Tune

On the Study of Piezoresistive Stress Sensors for Microelectronic Packaging

2000 ◽  
Vol 124 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Ben-Je Lwo ◽  
Ching-Hsing Kao ◽  
Tung-Sheng Chen ◽  
Yao-Shing Chen
Keyword(s):  
Input Power ◽  
Microelectronic Packaging ◽  
Piezoresistive Sensors ◽  
Four Point Bending ◽  
Stress Sensors ◽  
Linear Relationships ◽  
Study Test ◽  
As Stress ◽  
Test Chips ◽  
P Type

Stress measurements in microelectronic packaging through piezoresistive sensors take the advantage of both in-situ and nondestructive. In this study, test chips with both p-type and n-type piezoresistive stress sensors, as well as a heat source, were first designed, then manufactured by a commercialized foundry so that the uniformity of the test chips was expected. Both temperature and stress calibrations were next performed through a special designed MQFP (Metal Quad Flat Package) and four-point bending (4PB) structure, respectively. Measurements of stresses which are produced due to both manufacturing process and thermal effects on the test chips were finally executed, and approximately linear relationships were observed between stress and temperature as well as stress and input power. It is concluded that n-type piezoresistive stress sensors are able to extract stress in microelectronic packaging with good accuracy.

The Resolution and Contrast in Biological Sections Determined by Inelastic and Elastic Scattering

1973 ◽  
Vol 31 ◽  
pp. 224-225
Author(s):  
D. L. Misell
Keyword(s):  
Electron Microscopy ◽  
Adverse Effect ◽  
Elastic Scattering ◽  
Inelastic Scattering ◽  
Amorphous Carbon ◽  
Polymeric Materials ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Quantitative Estimates ◽  
Elastic Ratio

In the electron microscopy of biological sections the adverse effect of chromatic aberration on image resolution is well known. In this paper calculations are presented for the inelastic and elastic image intensities using a wave-optical formulation. Quantitative estimates of the deterioration in image resolution as a result of chromatic aberration are presented as an alternative to geometric calculations. The predominance of inelastic scattering in the unstained biological and polymeric materials is shown by the inelastic to elastic ratio, I/E, within an objective aperture of 0.005 rad for amorphous carbon of a thickness, t=50nm, typical of biological sections; E=200keV, I/E=16.

Application Of Electron Microscopy To Automotive Finish Defect Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 258-259
Author(s):  
Martin J. Mahon ◽  
Patrick W. Keating ◽  
John T. McLaughlin
Keyword(s):  
Electron Microscopy ◽  
Zero Tolerance ◽  
Polymeric Materials ◽  
Plant Management ◽  
Defect Analysis ◽  
X Ray ◽  
Root Cause ◽  
Cutting Out ◽  
Foreign Materials ◽  
Automotive Finish

Coatings are applied to appliances, instruments and automobiles for a variety of reasons including corrosion protection and enhancement of market value. Automobile finishes are a highly complex blend of polymeric materials which have a definite impact on the eventual ability of a car to sell. Consumers report that the gloss of the finish is one of the major items they look for in an automobile.With the finish being such an important part of the automobile, there is a zero tolerance for paint defects by auto assembly plant management. Owing to the increased complexity of the paint matrix and its inability to be “forgiving” when foreign materials are introduced into a newly applied finish, the analysis of paint defects has taken on unparalleled importance. Scanning electron microscopy with its attendant x-ray analysis capability is the premier method of examining defects and attempting to identify their root cause.Defects are normally examined by cutting out a coupon sized portion of the autobody and viewing in an SEM at various angles.

Colloidal systems in soils

1994 ◽  
Vol 52 ◽  
pp. 64-65
Author(s):  
J. Thieme ◽  
J. Niemeyer ◽  
P. Guttman
Keyword(s):  
Clay Minerals ◽  
Polymeric Materials ◽  
Spatial Arrangement ◽  
High Specific Surface Area ◽  
Turnover Rates ◽  
Colloidal Systems ◽  
Chemical Conditions ◽  
Aggregation Phenomena ◽  
Iron And Manganese ◽  
Soil Colloids

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.

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