scholarly journals Performance Evaluation of Knitted and Stitched Textile Strain Sensors

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7236
Author(s):  
Kaspar M.B. Jansen
Keyword(s):  
Relevant Literature ◽  
Ease Of Use ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Fully Integrated ◽  
Textile Fabrics ◽  
Conductive Yarns ◽  
The Many ◽  
Fashion Designers ◽  
Manufacturing Parameters

By embedding conductive yarns in, or onto, knitted textile fabrics, simple but robust stretch sensor garments can be manufactured. In that way resistance based sensors can be fully integrated in textiles without compromising wearing comfort, stretchiness, washability, and ease of use in daily life. The many studies on such textile strain sensors that have been published in recent years show that these sensors work in principle, but closer inspection reveals that many of them still have severe practical limitations like a too narrow working range, lack of sensitivity, and undesired time-dependent and hysteresis effects. For those that intend to use this technology it is difficult to determine which manufacturing parameters, shape, stitch type, and materials to apply to realize a functional sensor for a given application. This paper therefore aims to serve as a guideline for the fashion designers, electronic engineers, textile researchers, movement scientists, and human–computer interaction specialists planning to create stretch sensor garments. The paper is limited to textile based sensors that can be constructed using commercially available conductive yarns and existing knitting and embroidery equipment. Within this subtopic, relevant literature is discussed, and a detailed quantitative comparison is provided focusing on sensor characteristics like the gauge factor, working range, and hysteresis.

scholarly journals Development of Highly Sensitive Strain Sensor Using Area-Arrayed Graphene Nanoribbons

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1701
Author(s):  
Ken Suzuki ◽  
Ryohei Nakagawa ◽  
Qinqiang Zhang ◽  
Hideo Miura
Keyword(s):  
Graphene Nanoribbons ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Bending Test ◽  
Gauge Factor ◽  
Four Point Bending ◽  
Current Voltage ◽  
Highly Sensitive ◽  
Current Voltage Relationship

In this study, a basic design of area-arrayed graphene nanoribbon (GNR) strain sensors was proposed to realize the next generation of strain sensors. To fabricate the area-arrayed GNRs, a top-down approach was employed, in which GNRs were cut out from a large graphene sheet using an electron beam lithography technique. GNRs with widths of 400 nm, 300 nm, 200 nm, and 50 nm were fabricated, and their current-voltage characteristics were evaluated. The current values of GNRs with widths of 200 nm and above increased linearly with increasing applied voltage, indicating that these GNRs were metallic conductors and a good ohmic junction was formed between graphene and the electrode. There were two types of GNRs with a width of 50 nm, one with a linear current–voltage relationship and the other with a nonlinear one. We evaluated the strain sensitivity of the 50 nm GNR exhibiting metallic conduction by applying a four-point bending test, and found that the gauge factor of this GNR was about 50. Thus, GNRs with a width of about 50 nm can be used to realize a highly sensitive strain sensor.

scholarly journals Giant gauge factor of Van der Waals material based strain sensors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjie Yan ◽  
Huei-Ru Fuh ◽  
Yanhui Lv ◽  
Ke-Qiu Chen ◽  
Tsung-Yin Tsai ◽  
...  
Keyword(s):  
Carrier Mobility ◽  
Large Range ◽  
Van Der Waals ◽  
High Sensitivity ◽  
Strain Sensors ◽  
Strain Gauges ◽  
Gauge Factor ◽  
Proof Of Concept ◽  
High Flexibility ◽  
Small Deformations

AbstractThere is an emergent demand for high-flexibility, high-sensitivity and low-power strain gauges capable of sensing small deformations and vibrations in extreme conditions. Enhancing the gauge factor remains one of the greatest challenges for strain sensors. This is typically limited to below 300 and set when the sensor is fabricated. We report a strategy to tune and enhance the gauge factor of strain sensors based on Van der Waals materials by tuning the carrier mobility and concentration through an interplay of piezoelectric and photoelectric effects. For a SnS2 sensor we report a gauge factor up to 3933, and the ability to tune it over a large range, from 23 to 3933. Results from SnS2, GaSe, GeSe, monolayer WSe2, and monolayer MoSe2 sensors suggest that this is a universal phenomenon for Van der Waals semiconductors. We also provide proof of concept demonstrations by detecting vibrations caused by sound and capturing body movements.

scholarly journals Anisotropic, Wrinkled, and Crack-Bridging Structure for Ultrasensitive, Highly Selective Multidirectional Strain Sensors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Heng Zhang ◽  
Dan Liu ◽  
Jeng-Hun Lee ◽  
Haomin Chen ◽  
Eunyoung Kim ◽  
...  
Keyword(s):  
Rational Design ◽  
Full Range ◽  
Human Motion ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Wearable Electronics ◽  
Trade Off ◽  
Human Motion Detection ◽  
Sensing Applications ◽  
Anisotropic Structures

AbstractFlexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications. Although considerable efforts have been made to construct anisotropic structures for improved selective sensing capabilities, existing anisotropic sensors suffer from a trade-off between high sensitivity and high stretchability with acceptable linearity. Here, an ultrasensitive, highly selective multidirectional sensor is developed by rational design of functionally different anisotropic layers. The bilayer sensor consists of an aligned carbon nanotube (CNT) array assembled on top of a periodically wrinkled and cracked CNT–graphene oxide film. The transversely aligned CNT layer bridge the underlying longitudinal microcracks to effectively discourage their propagation even when highly stretched, leading to superior sensitivity with a gauge factor of 287.6 across a broad linear working range of up to 100% strain. The wrinkles generated through a pre-straining/releasing routine in the direction transverse to CNT alignment is responsible for exceptional selectivity of 6.3, to the benefit of accurate detection of loading directions by the multidirectional sensor. This work proposes a unique approach to leveraging the inherent merits of two cross-influential anisotropic structures to resolve the trade-off among sensitivity, selectivity, and stretchability, demonstrating promising applications in full-range, multi-axis human motion detection for wearable electronics and smart robotics.

scholarly journals A Novel Textile Stitch-Based Strain Sensor for Wearable End Users

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1469 ◽  
Author(s):  
Orathai Tangsirinaruenart ◽  
George Stylios
Keyword(s):  
Mechanical Properties ◽  
Electrical Resistance ◽  
Body Movement ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Heart Monitoring ◽  
Textile Sensors ◽  
Good Repeatability ◽  
The Ideal

This research presents an investigation of novel textile-based strain sensors and evaluates their performance. The electrical resistance and mechanical properties of seven different textile sensors were measured. The sensors are made up of a conductive thread, composed of silver plated nylon 117/17 2-ply, 33 tex and 234/34 4-ply, 92 tex and formed in different stitch structures (304, 406, 506, 605), and sewn directly onto a knit fabric substrate (4.44 tex/2 ply, with 2.22, 4.44 and 7.78 tex spandex and 7.78 tex/2 ply, with 2.22 and 4.44 tex spandex). Analysis of the effects of elongation with respect to resistance indicated the ideal configuration for electrical properties, especially electrical sensitivity and repeatability. The optimum linear working range of the sensor with minimal hysteresis was found, and the sensor’s gauge factor indicated that the sensitivity of the sensor varied significantly with repeating cycles. The electrical resistance of the various stitch structures changed significantly, while the amount of drift remained negligible. Stitch 304 2-ply was found to be the most suitable for strain movement. This sensor has a wide working range, well past 50%, and linearity (R2 is 0.984), low hysteresis (6.25% ΔR), good gauge factor (1.61), and baseline resistance (125 Ω), as well as good repeatability (drift in R2 is −0.0073). The stitch-based sensor developed in this research is expected to find applications in garments as wearables for physiological wellbeing monitoring such as body movement, heart monitoring, and limb articulation measurement.

Multiple neuromas coexisting with rheumatoid synovitis and a rheumatoid nodule

2000 ◽  
Vol 90 (5) ◽  
pp. 252-255 ◽  
Author(s):  
LA Zielaskowski ◽  
SJ Kruljac ◽  
JJ DiStazio ◽  
S Bastacky
Keyword(s):  
Rare Case ◽  
Relevant Literature ◽  
Rheumatoid Nodule ◽  
Morton’S Neuroma ◽  
Forefoot Pain ◽  
Rheumatoid Nodules ◽  
Morton's Neuroma ◽  
The Many

The authors present a rare case of multiple intermetatarsal neuromas coexisting with rheumatoid synovitis and a rheumatoid nodule. A brief review of rheumatoid nodules as a source of forefoot pain and a review of the relevant literature are provided. A rheumatoid nodule is just one of the many diagnoses that must be considered when one encounters pedal symptoms similar to those associated with Morton's neuroma.

Demystifying intuition as the main decision system used by farmers.

2021 ◽  
Vol 16 (10) ◽  
Author(s):  
Peter Nuthall
Keyword(s):  
Decision Making ◽  
Literature Search ◽  
Relevant Literature ◽  
Farm Management ◽  
Decision Making Process ◽  
Decision System ◽  
Intuitive Process ◽  
Important Improvement ◽  
The Many ◽  
Do So

Abstract Over the decades, many researchers have explored the concept of intuition as a decision-making process. However, most of this research does not quantify the important aspects of intuition, making it difficult to fully understand its nature and improve the intuitive process, enabling an efficient method of decision-making. The research described here, through a review of the relevant literature, demystifies intuition as a decision system by isolating the important intuition determining variables and relating them to quantitative intuition research. As most farm decisions are made through intuition, farmers, consultants, researchers and students of farm management will find the review useful, stimulating efforts for improving decision-making skills in farmers. The literature search covered all journals and recent decades and includes articles that consider the variables to be targeted in improving intuitive skill. This provides a basis for thinking about intuition and its improvement within the farming world. It was found from the literature that most of the logical areas that should influence decisions do in fact do so and should be targeted in improving intuition. One of the most important improvement processes is a farmer's self-criticism skills through using a decision diary in conjunction with reflection and consultation leading to improved decisions. This must be in conjunction with understanding, and learning about, the many other variables also impacting on intuitive skill.

scholarly journals A novel strain sensor using a microchannel embedded in PDMS

2018 ◽  
Vol 4 (2) ◽  
pp. 1 ◽  
Author(s):  
Angelica Campigotto ◽  
Stephane Leahy ◽  
Ayan Choudhury ◽  
Guowei Zhao ◽  
Yongjun Lai
Keyword(s):  
Finite Element ◽  
Rotation Angle ◽  
Strain Sensor ◽  
Element Model ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Sectional Area ◽  
Cross Sectional ◽  
Higher Sensitivity

A novel, inexpensive, and easy-to-use strain sensor using polydimethylsiloxane (PDMS)  was developed. The sensor consists of a microchannel that is partially filled with a coloured liquid and embedded in a piece of PDMS. A finite element model was developed to optimize the geometry of the microchannel to achieve higher sensitivity. The highest gauge factor that was measured experimentally was 41. The gauge factor was affected by the microchannel’s square cross-sectional area, the number of basic units in the microchannel, and the inlet and outlet configuration. As a case study, the developed strain sensors were used to measure the rotation angle of the wrist and finger joints.

On finding of high piezoresistive response of carbon nanotube films without surfactants for in-plane strain detection

2011 ◽  
Vol 22 (18) ◽  
pp. 2155-2159 ◽  
Author(s):  
Y. Miao ◽  
L. Chen ◽  
Y. Lin ◽  
R. Sammynaiken ◽  
W. J. Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Plane Strain ◽  
Composite Films ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Experimental Discovery ◽  
Strain Detection ◽  
Nanotube Films

The use of carbon nanotubes (CNTs) for construction of sensors is promising. This is due to some unique characteristics of CNTs. In recent years, strain sensors built from CNT composite films have been developed; however, their low piezoresistive sensitivity (gauge factor (GF)) in in-plane strain detection is a concern compared with other strain sensors. This article reports an experimental discovery of the superior piezoresistive response of a CNT film that is free of surfactants, known as the pure CNT film. The mechanism for the high GF with the pure CNT film strain sensors is also discussed.

The Role of Fluid Mechanics in Atherogenesis

1980 ◽  
Vol 102 (3) ◽  
pp. 181-189 ◽  
Author(s):  
R. M. Nerem ◽  
J. F. Cornhill
Keyword(s):  
Experimental Data ◽  
Fluid Mechanics ◽  
Relevant Literature ◽  
Ohio State University ◽  
Future Research ◽  
State University ◽  
Arterial Lesions ◽  
The Ohio State University ◽  
The Many

A specialists meeting on “The Role of Fluid Mechanics in Atherogenesis” was held August 24–25, 1978, at The Ohio State University. This meeting was a followup to a similar meeting held in 1974 [1, 2]. The present status of our knowledge of the importance of fluid mechanics in the initiation and progression of arterial lesions is summarized on the basis of the experimental data presented at the meeting; no attempt is made to provide a comprehensive review of the relevant literature. Three basic aspects are addressed: firstly, the localization of arterial lesions; secondly, the local hemodynamics of arterial segments with a high predilection to the development of lesions; and thirdly, the interaction of hemodynamic factors with the arterial wall. The many unresolved questions, apparently conflicting experimental data and areas in need of future research on the role of fluid mechanics in atherogenesis are identified specifically.

scholarly journals A Fully Inkjet-Printed Strain Sensor Based on Carbon Nanotubes

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 792 ◽  
Author(s):  
Hsuan-Ling Kao ◽  
Cheng-Lin Cho ◽  
Li-Chun Chang ◽  
Chun-Bing Chen ◽  
Wen-Hung Chung ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Morphology ◽  
Silver Film ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Lower Sensitivity ◽  
High Reproducibility ◽  
Silver Films ◽  
Microcrack Detection

A fully inkjet-printed strain sensor based on carbon nanotubes (CNTs) was fabricated in this study for microstrain and microcrack detection. Carbon nanotubes and silver films were used as the sensing layer and conductive layer, respectively. Inkjet-printed CNTs easily undergo agglomeration due to van der Waals forces between CNTs, resulting in uneven films. The uniformity of CNT film affects the electrical and mechanical properties. Multi-pass printing and pattern rotation provided precise quantities of sensing materials, enabling the realization of uniform CNT films and stable resistance. Three strain sensors printed eight-layer CNT film by unidirectional printing, rotated by 180° and 90° were compared. The low density on one side of eight-layer CNT film by unidirectional printing results in more disconnection and poor connectivity with the silver film, thereby, significantly increasing the resistance. For 180° rotation eight-layer strain sensors, lower sensitivity and smaller measured range were found because strain was applied to the uneven CNT film resulting in non-uniform strain distribution. Lower resistance and better strain sensitivity was obtained for eight-layer strain sensor with 90° rotation because of uniform film. Given the uniform surface morphology and saturated sheet resistance of the 20-layer CNT film, the strain performance of the 20-layer CNT strain sensor was also examined. Excluding the permanent destruction of the first strain, 0.76% and 1.05% responses were obtained for the 8- and 20-layer strain sensors under strain between 0% and 3128 µε, respectively, which demonstrates the high reproducibility and recoverability of the sensor. The gauge factor (GF) of 20-layer strain sensor was found to be 2.77 under strain from 71 to 3128 µε, which is higher than eight-layer strain sensor (GF = 1.93) due to the uniform surface morphology and stable resistance. The strain sensors exhibited a highly linear and reversible behavior under strain of 71 to 3128 µε, so that the microstrain level could be clearly distinguished. The technology of the fully inkjet-printed CNT-based microstrain sensor provides high reproducibility, stability, and rapid hardness detection.

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