Influence of test fluid on fabric permeability measurements and implications for processing of liquid moulded composites

Steenkamer, D. A.; Wilkins, Dick J.; Karbhari, Vistasp M.

doi:10.1007/bf00420189

Cited by 19 publications

(8 citation statements)

References 3 publications

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“…Figure 8 shows the permeability of the jute fabric for different porosities measured with the two different test fluids. As observed by other authors [18,19], the dependence of unsaturated permeability on the type of fluid evidences the importance of the wetting behavior and capillary forces acting during the infiltration process. Although the saturated permeability is a geometrical property not dependent on the pressure field or the capillary pressure, the measured transient permeability (or unsaturated permeability) is affected by the pressure distribution along the fiber bed.…”

Section: Constantsupporting

confidence: 77%

“…This equation is valid for fully saturated flow, but in LCM, the processes imply the infiltration of a dry reinforcement. Several authors have shown that the use of Darcy's law to describe unsaturated flow can lead to inappropriate predictions of the flow front position and pressure profile [11,[16][17][18][19][20][21][22][23][24], because it does not take into account the contribution of the capillary effects to the total pressure gradient. Thus, a more accurate expression of Darcy's law can be written if the capillary pressure is considered on the pressure gradient (DP).…”

Section: Theorymentioning

confidence: 99%

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Capillary effects in vacuum‐assisted resin transfer molding with natural fibers

et al. 2012

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The study of the capillary flow developed during the processing of composite materials is key because it acts as an important driving force for the impregnation of the fiber tows. It is also the main mechanism of void formation during infiltration of the fibers. In this work, capillary pressure of jute/vinylester composites was measured and the impact of capillary forces on fabric permeability was analyzed. It was found that the capillary pressure was significantly higher in vegetal than in synthetic fiber fabrics. In addition, the permeability of the fibers was characterized using various fluids. The resulting permeability was influenced by the nature of fluid and its polar property. Finally, the capillary pressure measured by this work was used to correct the experimental permeability in order to obtain a property independent of the test fluid. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

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Section: Constantsupporting

confidence: 77%

Section: Theorymentioning

confidence: 99%

Capillary effects in vacuum‐assisted resin transfer molding with natural fibers

et al. 2012

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“…Figure 8 shows the permeability of the jute fabric for different porosities measured with the two different test fluids. As observed by other authors [18, 19], the dependence of unsaturated permeability on the type of fluid evidences the importance of the wetting behavior and capillary forces acting during the infiltration process. Although the saturated permeability is a geometrical property not dependent on the pressure field or the capillary pressure, the measured transient permeability (or unsaturated permeability) is affected by the pressure distribution along the fiber bed.…”

Section: Resultssupporting

confidence: 75%

“…This equation is valid for fully saturated flow, but in LCM, the processes imply the infiltration of a dry reinforcement. Several authors have shown that the use of Darcy's law to describe unsaturated flow can lead to inappropriate predictions of the flow front position and pressure profile [11, 16–24], because it does not take into account the contribution of the capillary effects to the total pressure gradient. Thus, a more accurate expression of Darcy's law can be written if the capillary pressure is considered on the pressure gradient (Δ P ).…”

Section: Theorymentioning

confidence: 99%

Neuroglobin expression in the rat suprachiasmatic nucleus: Colocalization, innervation, and response to light

Hundahl

Hannibal

Fahrenkrug

et al. 2010

J of Comparative Neurology

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Neuroglobin (Ngb) is a myoglobin-like (Mb) heme-globin, belonging the globin family located only in neuronal tissue of the central nervous system. Ngb has been shown to be upregulated in and to protect neurons from hypoxic and ischemic injury, but the function of Ngb-in particular how Ngb may protect neurons-remains largely elusive. We have previously described the localization of Ngb in the rat brain and found it to be expressed in areas primarily involved in sleep/wake, circadian, and food regulation. The present study was undertaken, using immunohistochemistry, to characterize the localization, colocalization, innervation, and response to light of Ngb-immunoreactive (IR) cells in the rat suprachiasmatic nucleus (SCN). Our results demonstrate that the majority of Ngb-expressing neurons in the SCN belong to a cell group not previously characterized by neurotransmitter content; only a small portion was found to co-store GRP in the ventral SCN. Furthermore, some Ngb-containing neurons were responsive to light stimulation at late night evaluated by the induction of cFOS and only a few cells were found to express the core clock gene PER1 during the 24-hour light/dark cycle. The Ngb-containing cells received input from neuropeptide Y (NPY)-containing nerve fibers of the geniticulo-hypothalamic tract (GHT), whereas no direct input from the eye or the midbrain raphe system was demonstrated. The results indicate that the Ngb could be involved in both photic and nonphotic entrainment via input from the GHT.

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“…Steenkammer and co-workers [99,100] and Grif®n et al [95] have both reported signi®cant differences in the permeabilities measured in notionally similar reinforcement stacks when the permeating¯uid is changed. There is scope for an extensive study of the interrelationship between permeability and the microstructure parameters controlling the¯ow process.…”

Section: Resin Transfer Mouldingmentioning

confidence: 97%