scholarly journals Practical Evaluation of Printed Strain Sensors Based on Long-Term Static Strain Measurements

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4812
Author(s):  
Daniel Zymelka ◽  
Kazuyoshi Togashi ◽  
Toshihiro Takeshita ◽  
Takahiro Yamashita ◽  
Takeshi Kobayashi
Keyword(s):  
Sensor Arrays ◽  
Strain Analysis ◽  
Strain Sensors ◽  
Engineering Structures ◽  
Test Environment ◽  
Strain Measurements ◽  
Static Strain ◽  
Long Term Stability ◽  
Printed Sensors

Recent progress in printable electronics has enabled the fabrication of printed strain sensors for diverse applications. These include the monitoring of civil infrastructure, the gradual aging of which raises concerns about its effective maintenance and safety. Therefore, there is a need for automated sensing systems that provide information on the performance and behavior of engineering structures that are subjected to dynamic and static loads. The application of printed strain sensors in structural health monitoring is of growing interest owing to its large-area and cost-effective fabrication process. Previous studies have proven the suitability of printable strain sensors for dynamic strain measurements on bridges; however, the analysis of the long-term stability of printed sensors during static strain measurements is still lacking. Thus, this study aims to assess the long-term stability of printed strain sensor arrays and their suitability for the static strain analysis of large civil structures. The developed sensors and a dedicated wireless data acquisition system were deployed inside a gravity dam, which was selected as the field test environment. This test environment was chosen owing to the relatively stable temperature inside the dam and the very slow static strain changes associated with periodic water level changes. The results exhibited an average signal drift of 20 μϵ over 127 days. One of the sensor arrays was installed on a small crack in the dam structure; it showed that the sensors can track static strain changes owing to variations in the crack opening, which are related to the water level changes in the dam. Overall, the results of the developed sensors exhibit good strain sensitivity and low signal drift. This indicates the potential suitability of printed sensors for applications in the static strain analysis of engineering structures.

High Strain Monitoring during Fatigue Loading of Thermoplastic Composites Using Imbedded Draw Tower Fibre Bragg Grating Sensors

2008 ◽  
Vol 56 ◽  
pp. 441-446 ◽  
Author(s):  
Eli Voet ◽  
Geert Luyckx ◽  
Ives De Baere ◽  
Joris Degrieck ◽  
J. Vlekken ◽  
...  
Keyword(s):  
Composite Laminates ◽  
High Strength ◽  
Fatigue Loading ◽  
Strain Sensors ◽  
Thermoplastic Composites ◽  
Bragg Grating ◽  
Fibre Bragg Grating ◽  
Strain Measurements ◽  
Strain Monitoring

This paper presents the experimental study of fibre Bragg grating sensors for measuring strain inside composite laminates during fatigue loading. The optical fibres are imbedded inside thermoplastic CFRP test-coupons which have an ultimate strain of about 1.1%. Tension – tension fatigue cycling at a rate of 5Hz is been carried out at 314MPa with a maximum strain of 0.51%. At such extreme strain levels the use of high strength sensors becomes inevitable. Neither the sensor nor the composite test-coupons showed any significant degradation even after more than 500000 cycles. Fibre optic Bragg grating sensors are known to be very accurate strain sensors but one should be very careful interpreting their response once they are imbedded inside composite materials. In this study high strength fibre Bragg grating sensors with coating are imbedded in composite test coupons and a pretty good correlation was found between the strain measurements of an electrical extensometer and the imbedded sensor during the complete cycling. The high strength sensor show to be very feasible for extreme and long term strain measurements.

Electrical Characterisation of a Low-Density Layer of SnO Nanowires Deposited on a Set of Parallel Pt Electrodes

2008 ◽  
Vol 1080 ◽  
Author(s):  
Ilia Kiselev ◽  
Ilia Kiselev ◽  
Victor Sysoev ◽  
Thomas Schneider
Keyword(s):  
Statistical Approach ◽  
Sensor Arrays ◽  
Ambient Air ◽  
Low Density ◽  
Si Substrates ◽  
Long Term Stability ◽  
Current Voltage ◽  
Pt Electrodes ◽  
Stability Examination

ABSTRACTLow-density layers of SnO2 nanowires were produced using the vapor solid method and dry-pressed onto surface-oxidized Si-substrates equipped with a set of 39 parallel Pt-electrodes. Current-Voltage (I-V) characteristics of the segments between the electrodes were measured in ambient air at a substrate temperature of 300°C. Statistical analysis of the 38 I-V characteristics allows drawing conclusions, that only Schottky contacts between large nanowires and electrodes are significant for conductometry, and that they have very similar barrier characteristics. The statistical approach and its advantages are demonstrated. The clarity obtained concerning the roles of different resistivity mechanisms involved enables predictions of the nanowire net device behavior in applications, which is demonstrated on an instance of long-term stability examination of gas sensor arrays.

NANOSTRUCTURED PARTICLES AND LAYERS FOR SENSING CONTAMINANTS IN AIR AND WATER

NANO ◽  
2008 ◽  
Vol 03 (04) ◽  
pp. 205-208 ◽  
Author(s):  
PETER A. LIEBERZEIT ◽  
ABDUL REHMAN ◽  
SADAF YAQUB ◽  
FRANZ L. DICKERT
Keyword(s):  
Molecularly Imprinted Polymers ◽  
Quartz Crystal ◽  
Chemical Sensor ◽  
Sensor Arrays ◽  
Molybdenum Disulphide ◽  
Molecularly Imprinted ◽  
Acetate Concentration ◽  
Nanostructured Particles ◽  
Long Term Stability

Chemical sensor layers for environmental applications require optimal selectivity, sensitivity, and long term stability, which can be achieved in artificial matrices. For detecting thiols in air, reversible affinity interactions can be optimized by varying the stoichiometry of molybdenum disulphide nanoparticles to achieve sulphur deficiencies. Generating MoS1.9 increases the quartz crystal microbalance (QCM) sensor responses towards butane thiol by a factor of three. Artificial recognition sites are accessible by molecular imprinting: acrylate copolymers can be tuned in polarity to interact selectively with atrazine in water leading to detection limits below one ppb with QCM sensors. Finally, sensor arrays coated with six different molecularly imprinted polymers (MIP) correctly reproduce the ethyl acetate concentration of a composter over a period of two weeks validated by GC-MS measurements.

Stability and Change in Emotional Intelligence: Exploring the Transition to Young Adulthood

2005 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
James D.A. Parker ◽  
Donald H. Saklofske ◽  
Laura M. Wood ◽  
Jennifer M. Eastabrook ◽  
Robyn N. Taylor
Keyword(s):  
High School ◽  
Emotional Intelligence ◽  
Postsecondary Education ◽  
Life Transition ◽  
Full Time ◽  
Major Life ◽  
Long Term Stability ◽  
Time Period ◽  
Transition From High School

Abstract. The concept of emotional intelligence (EI) has attracted growing interest from researchers working in various fields. The present study examined the long-term stability (32 months) of EI-related abilities over the course of a major life transition (the transition from high school to university). During the first week of full-time study, a large group of undergraduates completed the EQ-i:Short; 32 months later a random subset of these students (N = 238), who had started their postsecondary education within 24 months of graduating from high school, completed the measures for a second time. The study found EI scores to be relatively stable over the 32-month time period. EI scores were also found to be significantly higher at Time 2; the overall pattern of change in EI-levels was more than can be attributed to the increased age of the participants.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

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