The thermal conductivity of textiles

Baxter, S.

doi:10.1088/0959-5309/58/1/310

Cited by 69 publications

(40 citation statements)

References 6 publications

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“…Standard test procedures were used to measure the physical properties of the nonwoven fabrics: ASTM D 6242 for areal density in gram per square meter (mass per unit area); ASTM D 5736 for thickness; ASTM D 1388 for flexural rigidity and bending modulus; ASTM D 5035 for tensile properties of breaking strength/elongation; ASTM D 737 for air permeability and thermal conductivity by Proceedings of Physical Society [10]. …”

Section: Other Testsmentioning

confidence: 99%

Development of Natural Fiber Nonwovens for Application as Car Interiors for Noise Control

Thilagavathi

Pradeep

Kannaian

et al. 2010

Journal of Industrial Textiles

183

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As natural fibers are noise-absorbing materials, renewable and biodegradable nonwovens have been developed using natural fibers such as banana, bamboo, and jute fibers for the automotive interiors to reduce noise, which currently contain traditional materials such as glass and other manufactured fibers and foams that are difficult to recycle. Three types of nonwovens were developed using needlepunching technique by blending bamboo, banana, and jute fibers with polypropylene staple fibers in the ratio of 50 : 50. Sound absorption coefficient was tested by impedance tube method (ASTM E 1050). Comparison of physical properties such as areal density, thickness, stiffness, tensile strength, elongation, structural properties, and comfort properties such as air permeability and thermal conductivity were performed for all samples. It is observed that the bamboo/polypropylene nonwoven with its compact structure showed, higher tensile strength, higher stiffness, lower elongation, lower thermal conductivity, lower air permeability, and good absorption coefficient than others and it is suitable for the automotive interior noise control. At 800 Hz, the absorption coefficient of bamboo/polypropylene and jute/ polypropylene is equivalent to the target level but it is lower by 22% in banana/ polypropylene. But at higher frequencies (1600 Hz), there is a reduction from the target level in all the nonwovens, which could be improved by increasing the thickness of the nonwovens.

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Section: Other Testsmentioning

confidence: 99%

Development of Natural Fiber Nonwovens for Application as Car Interiors for Noise Control

Thilagavathi

Pradeep

Kannaian

et al. 2010

Journal of Industrial Textiles

183

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“…At the same time, this flux cannot be greater than the heat flux through the area completely filled with keratin. The conductance quotient of keratin, according to indirect estimates [6][7][8], is greater than that of air approximately by an order of magnitude. Within the limits specified, q c increases linearly as the relative fraction of keratin in the area occupied by the pelage increases.…”

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confidence: 91%

The Insulating Properties of the Pelage of the North-American Porcupine (Erethizon dorsatum): The Influence of Quill-Like Structures on Heat Transfer

IuF

2005

Dokl Biol Sci

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Multifunctionality is characteristic of the hairy pelage of mammals, the key function of which is insulation. As a rule, mammalian fur can effectively insulate the body at a certain density of thin hair in it and sufficient thickness of the pelage in general [1]. The fulfillment of other functions (in particular, mechanical protection) may be related to changes in the pelage, as a result of which its structure becomes markedly different from the structure that may be regarded optimal from the standpoint of insulation. Apparently, more or less significant redistribution of roles between the insulating and defensive functions of the pelage took place in parallel more than once in the course of evolution of mammals. In particular, quill-like modifications of hair differing in the degree of modification occur in different taxa [2]. In extreme cases, the pelage turns into a strongly differentiated multilayer defensive formation consisting of a great number of various quills of a complex structure. Nevertheless, the functional aspects of these transformations have not been studied thus far. For example, it is unknown to which extent the presence of quills may affect the insulating properties of the pelage. Filling up this gap was the goal of this study, in which we performed quantitative estimation of the effect of the presence of quills on the insulating properties of the pelage using the North American porcupine ( Erethizon dorsatum L . ) as an example.Heat transfer within the pelage at temperatures lower than the thermoneutral zone characteristic of a certain individual may proceed in three ways: via thermal conductance, heat radiation, and convection [3]. Because convective heat losses, most likely, are small under natural conditions [3], the effectiveness of the pelage as an insulator is determined primarily by thermal conductance and heat radiation. In the absence of convection and evaporation, the total intensity of heat flux q through the pelage can be presented as a sum of two summands [4][5][6]:where q c is the heat flux via thermal conductance per se through air and hair, and q r is the heat flux via radiation. The heat flux through the pelage via thermal conductance cannot be lower than the flux through the still air layer whose thickness is similar to that of the pelage. At the same time, this flux cannot be greater than the heat flux through the area completely filled with keratin. The conductance quotient of keratin, according to indirect estimates [6][7][8], is greater than that of air approximately by an order of magnitude. Within the limits specified, q c increases linearly as the relative fraction of keratin in the area occupied by the pelage increases. Let us present fur as long solid cylinders; in this case, the relative fraction of keratin will be proportional to the product of hair density N by the squared diameter ( d ) of hair cross section: Nd 2 [5]. Thus, the dimensionless product Nd 2 , hereinafter designated as I h -c , may be regarded as a measure of the effect of pelage structure on the i...

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“…This formula was later used by Baxter ( 1946) to study the thermal conductivity of textiles. Verschoor and Greebler ( 1952) treat a glass fibrous insulation as though the volume fraction of fiber is in series with the volume fraction of gas, which means that the first part in equation (2.7) is omitted (a = 0 and sR = s).…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer in Fibrous Materials

Bankvall¹

1973

Journal of Testing and Evaluation

114

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Värmetransport i fibrösa material Claes G. Bankvall Rapporten presenterar teorier för och mätningar av värmetransportmekanis-merna i fibermaterial ( dvs isolering av mineralullstyp). Arbetet är del av ett större forskningsprogram vid Institutionen för Byggnadsteknik I, LTH, som behandlar materialetsfunktion som vär-meisolering. En preliminär version av rapporten publicerades på svenska 1970.I det fibrösa materialet förekommer olika typer av värmetransport: värmeled-ning i fibrerna och gasen samt strålning. I rapporten beräknas dessa mekanismer teoretiskt. Teorierna verifieras experimentellt genom mätningar på ett glasfibermaterial i en speciellt konstruerad plattapparat Det visas att teorierna ger en fullständig förklaring av värme-transportmekanismernas inverkan på materialets totala effektiva värmeled-ningsförmåga. Inom byggnadssektorn har behovet av effektiva värmeisoleringsmaterial ökat pga ökade krav på komfort och krav på reducering av byggnadskostnaderna. Det är inte möjligt att bedöma ett isoleringsmaterials uppförande i en väggkon-struktion utan kännedom om hur olika typer av värme transporteras genom materialet. Ytterligare kunskaper om isoleringsmaterialets funktionssätt och egenskaper behövs för att materialet skall kunna utnyttjas effektivt.Hogisolerande material är t ex cellplaster och mineralull. Inom byggnadstekniken har särskilt de fibrösa materialen med öppet porsystem och relativt komplex värmetransportmekamsm medfört svårigheter vid bedömning av byggnadskonstruktioner där sådant material utgör isolering. VärmeledningsförmågaI fibermaterialet förekommer olika typer av värmetransport: vitrmeledning i fast fas (fibrer), strålning i materialet och värmetransport i den i isoleringen inneslutna gasen. Den totala effektiva värme-ledningsförmågan i ett fibermaterial, Å, kan uttryckas genom sambandet (1) där ..l 0 är den effektiva värmelednings-förmågan pga ledning i gas och beror på ledning i gasen och ledning i gas och fiber omväxlande. Den effektiva värmeledningsförmågan pga ledning i fast fas, Åp, beror på direkt ledning i fibrer och kontaktpunkten mellan fibrer. Strålningens inverkan på värmelednings-förmågan betecknas .AR· Värmetransport pga fibrer och gasVid undersökning av värmeledningsför-mågan pga fibrer och gas kan materialet behandlas som en kombination av fast fas och gasfas. Den effektiva värmeled-ningsförmågan kan då uttryckas som

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The thermal conductivity of textiles

Cited by 69 publications

References 6 publications

Development of Natural Fiber Nonwovens for Application as Car Interiors for Noise Control

Development of Natural Fiber Nonwovens for Application as Car Interiors for Noise Control

The Insulating Properties of the Pelage of the North-American Porcupine (Erethizon dorsatum): The Influence of Quill-Like Structures on Heat Transfer

Heat Transfer in Fibrous Materials

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