title: Fast magnetic reconnection and the coalescence instability

authors: Craig, Ian J.D.

subjects: mathematics

abstract: The magnetic reconnection that occurs during the nonlinear development of the coalescence instability is considered. The structure of the reconnection region at the time of maximum current as a function of the resistivity η is analyzed in detail using a compressible magnetohydrodynamic fluid code. It is shown that the numerical results concur remarkably well with a simple scaling analysis which predicts the dependence of the reconnection region structure on η. It is argued that the flow topology is crucial in maintaining the ``fast'' reconnection rate. The results indicate a flux pileup solution in which the flux annihilation rate is approximately independent of η, whereas the Ohmic dissipation rate scales as η −1/3. The possibility that these scalings break down at lower values of η is discussed.

text: Fast magnetic reconnection and the coalescence instability The magnetic reconnection that occurs during the nonlinear development of the coalescence instability is considered. The structure of the reconnection region at the time of maximum current as a function of the resistivity η is analyzed in detail using a compressible magnetohydrodynamic fluid code. It is shown that the numerical results concur remarkably well with a simple scaling analysis which predicts the dependence of the reconnection region structure on η. It is argued that the flow topology is crucial in maintaining the ``fast'' reconnection rate. The results indicate a flux pileup solution in which the flux annihilation rate is approximately independent of η, whereas the Ohmic dissipation rate scales as η −1/3. The possibility that these scalings break down at lower values of η is discussed.

year: 1993-03

title: Interfacial modification of hemp fiber reinforced composites using fungal and alkali treatment

authors: Pickering, Kim L.

subjects: natural fibers

abstract: Increasing worldwide environmental awareness is encouraging scientific research into developing cheaper, more sustainable materials. Industrial hemp fiber is one of the strongest and stiffest available natural fibers [K. L. Pickering, M. Priest, T. Watts, G. Beckermann, and S. N. Alam, J. Adv. Mater. 37, 15 (2005)] and therefore has great potential in composite materials. Incorporated into a thermoplastic matrix, it gives a structural material that is cheap, lightweight, and recyclable. However, natural fibers are commonly incompatible with common molding thermoplastics such as polypropylene, which limits the performance of the composites produced. The main objective of the current work was to investigate the use of fungi to treat hemp fiber to create better bonding characteristics in natural fiber reinforced polypropylene composites. X-ray diffraction (XRD), ζ-potential, lignin testing, thermal analysis, and scanning electron microscopy (SEM) were used to characterize the effect of treatment on hemp fibers. A combined alkali and fungi treated fiber composite produced the highest tensile strength of 48.3 MPa, an increase of 32% compared to composites with untreated fiber.

text: Interfacial modification of hemp fiber reinforced composites using fungal and alkali treatment Increasing worldwide environmental awareness is encouraging scientific research into developing cheaper, more sustainable materials. Industrial hemp fiber is one of the strongest and stiffest available natural fibers [K. L. Pickering, M. Priest, T. Watts, G. Beckermann, and S. N. Alam, J. Adv. Mater. 37, 15 (2005)] and therefore has great potential in composite materials. Incorporated into a thermoplastic matrix, it gives a structural material that is cheap, lightweight, and recyclable. However, natural fibers are commonly incompatible with common molding thermoplastics such as polypropylene, which limits the performance of the composites produced. The main objective of the current work was to investigate the use of fungi to treat hemp fiber to create better bonding characteristics in natural fiber reinforced polypropylene composites. X-ray diffraction (XRD), ζ-potential, lignin testing, thermal analysis, and scanning electron microscopy (SEM) were used to characterize the effect of treatment on hemp fibers. A combined alkali and fungi treated fiber composite produced the highest tensile strength of 48.3 MPa, an increase of 32% compared to composites with untreated fiber.

year: 2007

title: Ka ora | Ka mate

authors: Apiata, Hāwea

abstract: Ekphrasis in response to the artwork 'Matariki' by Hariata Ropata-Tangahoe (Ngāti Toa, Ngāti Raukawa, Te Āti Awa). Written for the One Hundred Years exhibition held at RAMP Gallery, in celebration of the establishment of the first iteration of the technical college a century earlier in 1924. Alumni of the art program were invited to contribute works to the show and local writers were asked to respond to the art, with their works being published in the exhibition catalogue.

text: Ka ora | Ka mate Ekphrasis in response to the artwork 'Matariki' by Hariata Ropata-Tangahoe (Ngāti Toa, Ngāti Raukawa, Te Āti Awa). Written for the One Hundred Years exhibition held at RAMP Gallery, in celebration of the establishment of the first iteration of the technical college a century earlier in 1924. Alumni of the art program were invited to contribute works to the show and local writers were asked to respond to the art, with their works being published in the exhibition catalogue.

year: 2024-02-29