Structural Parameters Affecting Electrothermal Properties of Woolen Knitted Fabrics Integrated with Silver-Coated Yarns

Recently, more and more researchers have focused on electrical textiles that can provide or convert energy to facilitate people’s lives. Knitting conductive yarns into ordinary fabrics is a common way for electrical textiles to transmit heat or electrical signals to humans. This paper is aimed at studying the resistance values and temperatures of electrothermal knitted conductive fabric (EKCF) subjected to certain voltages over time. Six types of EKCFs with structural differences were fabricated using a computerized flat knitting machine with intarsia technology. Uniform samples 10 × 10 cm in size were made from wool, as were two different specifications of silver-coated conductive yarns. The wool yarn and one silver-coated yarn were mixed to knit a resistance area 2 × 2 cm in size in the center of the EKCF to observe heating behaviors. The experiment results showed that when the EKCFs were subjected to certain voltages over time, the resistance values of the resistance area increased over a short time and then gradually decreased, and the temperature gradually increased in the first 1000 s and tended toward stability after a certain period of time. The structural coefficient κ between different knitted structures (which predicted the thermal properties of different EKCFs subjected to different voltages) was analyzed. These results are of great significance for predicting the electrothermal performance of EKCFs with different knitted structures. On the basis of these results, an optimized knitted structure was selected as the best EKCF for wearable textiles, and the findings contribute to the field of technological and intelligent electrothermal garments and related products.

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Thermal properties of directionally oriented polymer fibrous materials as a function of fibre arrangement at mesoscopic level

Thermal Science ◽

10.2298/tsci181011105s ◽

2019 ◽

Vol 23 (5 Part B) ◽

pp. 3117-3127 ◽

Cited By ~ 1

Author(s):

Snezana Stankovic ◽

Dusan Popovic ◽

Goran Poparic

Keyword(s):

Heat Transfer ◽

Thermal Properties ◽

Structural Parameters ◽

Fibrous Materials ◽

Surface Geometry ◽

Knitted Fabrics ◽

Key Factor ◽

Cotton Yarns ◽

Mesoscopic Level ◽

And Migration

Thermal properties of directionally oriented fibrous materials have been investigated in this research with the purpose of considering the influence of fibre arrangement at mesoscopic level. The range of various distributions of fibres in the fibrous materials was obtained by applying different twist intensity during spinning of cotton fibres. From various twisted cotton yarns the knitted fabrics were produced under controlled conditions, so as to obtain as similar as possible constructions. This made possible to obtain the heterogeneity of the porous fibrous structures coming from the mesoscopic level. Thermal conductivity and heat transfer coefficient of the materials were investigated. The results obtained indicate the arrangement of fibres (or their compactness, orientation and migration), which, in turn, was determined by twist intensity (mesoscopic scale), as the key factor influencing thermal properties. Yarn compactness and fibre migration, determined by lateral forces imposed by the twist inserted in yarn, affected variations in structural parameters of the knitted fabrics, and thus influenced their thermal properties. Fibre orientation manifested itself in surface geometry of the yarn was also proved to have a considerable influence on heat transfer properties.

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Investigation into the effect of fabric structure on surface temperature distribution in weft-knitted fabrics using thermal imaging technique

Thermal Science ◽

10.2298/tsci180811290z ◽

2020 ◽

Vol 24 (3 Part B) ◽

pp. 1991-1998

Author(s):

Mozhgan Ziaei ◽

Mohammad Ghane ◽

Hossein Hasani ◽

Ahmad Saboonchi

Keyword(s):

Temperature Distribution ◽

Surface Temperature ◽

Knitted Fabrics ◽

Surface Temperature Distribution ◽

Fabric Structure ◽

Structural Differences ◽

Lower Heat ◽

Knitted Structure ◽

Single Jersey ◽

Double Cross

The aim of this paper was to evaluate the surface temperature distribution in several single and double jersey weft-knitted fabrics. Plain knitted fabrics as well as those with, double cross-tuck, cross-tuck, double cross-miss, and cross-miss pattern together with plain rib and interlock structures were under consideration in term of their structural differences. In order to investigate the temperature distribution in produced samples, all the fabrics were placed on a 35?C adjusted hot plate instrument and thermal images were captured by an infrared thermal camera. The results revealed that the presence of tuck stitches in single jersey weft-knitted fabrics increase the air permeability due to the increasing the fabrics? porosity, which in turn leads to decrease their thermal resistance as compared with plain knitted structure. On the other hand, addition of miss stitches in single jersey knitted structures would decrease the thickness of fabrics and improves their heat transfer ability. The obtained results, from rib and interlock knitted structures, suggested their lower heat conductivity in comparison to the single jersey knitted samples.

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The impact of different proportions of knitting elements on the resistive properties of conductive fabrics

Textile Research Journal ◽

10.1177/0040517518758003 ◽

2018 ◽

Vol 89 (5) ◽

pp. 881-890 ◽

Cited By ~ 3

Author(s):

Su Liu ◽

Yanping Liu ◽

Li Li

Keyword(s):

Contact Resistance ◽

Reference Source ◽

Wearable Electronics ◽

Electronic Textiles ◽

Knitted Fabrics ◽

Conductive Yarns ◽

Key Factor ◽

Resistive Networks ◽

The Impact ◽

Resistive Property

Conductive yarn is the key factor in fabricating electronic textiles. Generally, three basic fabric production methods (knit, woven, and non-woven) combined with two finishing processes (embroidery and print) are adopted to embed conductive yarns into fabrics to achieve flexible electronic textiles. Conductive yarns with knit structure are the most flexible and effective form of electronic textiles. Electronic textiles present many advantages over conventional electronics. However, in the process of commercialization of conductive knitted fabrics, it is a great challenge to control the complicated resistive networks in conductive knitted fabrics for the purpose of cost saving and good esthetics. The resistive networks in conductive knitted fabrics contain length-related resistance and contact resistance. The physical forms of conductive yarns in different fabrication structures can be very different and, thus, the contact resistance varies greatly in different fabrics. So far, study of controlling the resistive property of conductive fabrics has not been conducted. Therefore, establishing a systematic method for the industry as a reference source to produce wearable electronics is in great demand. During the industrialization of conductive knitted fabrics, engineers can estimate the resistive property of the fabric in advance, which makes the production process more effective and cost efficient. What is more, the resistive distribution in the same area of knitted fabrics can be fully controlled.

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What Influences Customer Satisfaction When? Product and Service Over Time

Journal of Management Research ◽

10.5296/jmr.v8i3.9538 ◽

2016 ◽

Vol 8 (3) ◽

pp. 45 ◽

Cited By ~ 1

Author(s):

Shueh-Chin Ting

Keyword(s):

Customer Satisfaction ◽

Service Performance ◽

Customer Relationship ◽

Long Time ◽

Curvilinear Relationships ◽

Short Time ◽

Time Frames ◽

Post Purchase ◽

Product Weight ◽

Over Time

Though researchers have examined the changes in the effects of product and service performance on customer satisfaction, the short time frames of most studies prevents deeper understanding of this relationship. This study collects information from pre-purchase to 15 years post-purchase from 11,056 potential and existing automobile customers in the Taiwan market. The data is analyzed by a regression model. Results reveal that the importance of both product and service performance change over long time and the long-term trends of product and service performance weights are non-linear. In addition, from pre-purchase to the second year post-purchase, service weight is higher than product weight, but after the third year, product weight exceeds service weight. Product and service weight on customer satisfaction over time exhibit curvilinear relationships. Therefore, which one of product or service a company should stress depends on the stage in the customer relationship.

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Investigation on Thermal Properties of Double-Layered Weft Knitted Fabrics

Materials Science ◽

10.5755/j01.ms.18.2.1921 ◽

2012 ◽

Vol 18 (2) ◽

Cited By ~ 6

Author(s):

Asta BIVAINYTĖ ◽

Daiva MIKUČIONIENĖ ◽

Paulius KERPAUSKAS

Keyword(s):

Thermal Properties ◽

Knitted Fabrics

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Trender i insidens og mortalitet av kreft i Norge

Norsk Epidemiologi ◽

10.5324/nje.v11i2.554 ◽

2009 ◽

Vol 11 (2) ◽

Author(s):

Steinar Tretli ◽

Trude Eid Robsahm ◽

Elisabeth Svensson

Keyword(s):

Case Fatality ◽

English Summary ◽

Classification Rules ◽

Font Size ◽

Treatment Results ◽

Mortality Trends ◽

Calendar Time ◽

Incidence And Mortality ◽

Short Time ◽

Over Time

ENGLISH SUMMARYTretli S, Robsahm TE, Svensson E. Time trends in cancer incidence and mortality in Norway.Nor J Epidemiol 2001; 11 (2): 177-185.The aim of this study is to decribe the trends in incidence and mortality of cancer by calendar time.Most types of cancer, except those with high case fatality short time after the diagnosis, demonstrate alarger increase in incidence than in mortality over time. For persons below 70 years of age during theperiod 1931-95 the mortality rate has been close to constant. Obviously, the mortality of lung andstomach cancer has changed over time, however, these have changed in different direction and almostlevelled out. In this paper, it is discussed how registration routines, classification rules, treatment resultsand the basis of the diagnosis can influence the incidence and mortality trends.

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383. Feasibility of Specimen Self-collection in Young Children Undergoing SARS-CoV-2 Surveillance for In-person Learning

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.584 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S293-S293

Author(s):

Jonathan Altamirano ◽

Grace Tam ◽

Marcela Lopez ◽

India Robinson ◽

Leanne Chun ◽

...

Keyword(s):

Young Children ◽

Time Window ◽

School Administrators ◽

Error Rates ◽

Independent Observer ◽

Specimen Collection ◽

Timing Data ◽

Short Time Window ◽

Short Time ◽

Over Time

Abstract Background While pediatric cases of COVID-19 are at low risk for adverse events, schoolchildren should be considered for surveillance as they can become infected at school and serve as sources of household or community transmission. Our team assessed the feasibility of young children self-collecting SARS-CoV-2 samples for surveillance testing in an educational setting. Methods Students at a K-8 school were tested weekly for SARS-CoV-2 from September 2020 - June 2021. Error rates were collected from September 2020 - January 2021. Clinical staff provided all students with instructions for anterior nares specimen self-collection and then observed them to ensure proper technique. Instructions included holding the sterile swab while making sure not to touch the tip, inserting the swab into their nostril until they start to feel resistance, and rubbing the swab in four circles before repeating the process in their other nostril. An independent observer timed random sample self-collections from April - June 2021. Results 2,590 samples were collected from 209 students during the study period when data on error rates were collected. Errors occurred in 3.3% of all student encounters (n=87). Error rates over time are shown in Figure 1, with the highest rate occurring on the first day of testing (n=20/197, 10.2%) and the lowest in January 2021 (n=1/202, 0.5%). 2,574 visits for sample self-collection occurred during the study period when independent timing data was collected (April - June 2021). Of those visits, 7.5% (n=193) were timed. The average duration of each visit was 70 seconds. Figure 1. Swab Error Rates Over Time Conclusion Pediatric self-collected lower nasal swabs are a viable and easily tolerated specimen collection method for SARS-CoV-2 surveillance in school settings, as evidenced by the low error rate and short time window of sample self-collection during testing. School administrators should expect errors to drop quickly after implementing testing. Disclosures All Authors: No reported disclosures

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Active Optimum Control of Orthotropic Plates Using Piezoelectric Stiffeners

14th Biennial Conference on Mechanical Vibration and Noise: Intelligent Structures, Materials, and Vibrations ◽

10.1115/detc1993-0157 ◽

1993 ◽

Author(s):

Victor Birman ◽

Sarp Adali

Keyword(s):

Time Interval ◽

Short Time Interval ◽

Bending Moments ◽

Optimum Control ◽

Orthotropic Plates ◽

Time Intervals ◽

Control Forces ◽

Short Time ◽

Alternating Voltage ◽

Over Time

Abstract Active control of orthotropic plates subjected to an impulse loading is considered. The dynamic response is minimized using in-plane forces or bending moments induced by piezoelectric stiffeners bonded to the opposite surfaces of the plate and placed symmetrically with respect to the middle plane. The control forces and moments are activated by a piece-wise constant alternating voltage with varying switch-over time intervals. The magnitude of voltage is bounded while the switch-over time intervals are constantly adjusted to achieve an optimum control. Numerical examples presented in the paper demonstrate the effectiveness of the method and the possibility of reducing the vibrations to very small amplitudes within a short time interval which is in the order of a second.

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Understanding Molecular Clocks and Time Trees

10.7591/cornell/9781501752773.003.0011 ◽

2021 ◽

pp. 326-337

Author(s):

Andrew V. Z. Brower ◽

Randall T. Schuh

Keyword(s):

Amino Acid ◽

Molecular Clock ◽

Significant Error ◽

Evolutionary Tree ◽

Molecular Clocks ◽

Amino Acid Substitutions ◽

Absolute Minimum ◽

Short Time ◽

Over Time ◽

Age Estimates

This chapter examines molecular clocks and time trees. Although laden with numerous process assumptions that may or may not be true (or knowable), the idea is appealingly straightforward: if amino acid substitutions in proteins occurred at a relatively steady pace that were more or less constant both over time and along each of the branches of a diverging evolutionary tree, then the number of substitutions would be directly related to the time since the taxa in question diverged from one another. However, evidence does not support a universal molecular clock. Evidence might or might not support “local” clocklike evolution among closely related taxa over relatively short time spans. Although absolute minimum ages for clades may be inferred from fossils, from biogeographical patterns, or extrapolated from secondary calibrations, such age estimates are subject to potentially significant error due to vagaries of geological dating as well as ambiguities of fossil identity. The test of a time tree hypothesis is to discover new fossil evidence that corroborates or falsifies it.

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Scaling Issues in Landscape Ecology

Essentials of Landscape Ecology ◽

10.1093/oso/9780198838388.003.0002 ◽

2019 ◽

pp. 14-41

Author(s):

Kimberly A. With

Keyword(s):

Landscape Ecology ◽

Spatial Patterns ◽

Spatial Scales ◽

Ecological Data ◽

Ecological Forecasting ◽

Spatial And Temporal Scales ◽

Time Periods ◽

Patterns And Processes ◽

Short Time ◽

Over Time

Spatial patterns are ubiquitous in nature, and ecological systems exhibit patchiness (heterogeneity) across a range of spatial and temporal scales. Landscape ecology is explicitly concerned with understanding how scale affects the measurement of heterogeneity and the scale(s) at which spatial pattern is important for ecological phenomena. Patterns and processes measured at fine spatial scales and over short time periods are unlikely to behave similarly at broader scales and extended time periods. An understanding of pattern-process linkages, a major research focus in landscape ecology, thus requires an understanding of how patterns change with scale, spatially and temporally. The development of methods for extrapolating information across scales is necessary for predicting how landscapes will change over time as well as for ecological forecasting. This chapter explores how scaling issues affect ecological investigations, discusses problems in identifying the correct scale for research, and outlines when and how ecological data can be extrapolated.

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