Search

Baby-led approaches to complementary feeding promote intake of family foods rather than infant specific foods, from the start of the complementary feeding period, which advocates suggest should be less expensive. However, this has never been formally examined. We recently completed a 2-year randomised controlled trial comparing baby-led (BLISS) and traditional spoon-feeding (Control) approaches to complementary feeding in 206 infants. Perceived expense was assessed at infant 7, 8, 9 and 12 months of age. The actual cost of intake (food offered, consumed and left over) was calculated from 3-day weighed diet records at 7 and 12 months of age. BLISS was perceived as less expensive than traditional feeding (P = 0.002), but comparisons of actual costs showed only small differences in total daily cost for food offered (NZ$0.20 and NZ$0.10 at 7 and 12 months, respectively), consumed (NZ$0.30, NZ$0.20) or left over (NZ$0.10, NZ$0.20). Baby-led approaches are not cheaper for families than traditional spoon-feeding., Author(s): S. Bacchus [sup.1], R. W. Taylor [sup.2], E. A. Fleming [sup.1], J. J. Haszard [sup.3], L. Fangupo [sup.1], L. Daniels [sup.1], A.-L. M. Heath [sup.1] Author Affiliations: (1) Department [...]

A high temperature superconducting (HTS) dynamo is a type of device known as a "flux pump" that can inject DC into a closed superconducting circuit. Here, we report experimental results from a variable-temperature dynamo-type HTS flux pump operated within a cryo-cooled chamber. This device employs a "continuous stator" topology, whereby an HTS "coated conductor" is wrapped to form a cylinder around a mechanical rotor such that applied flux from the rotor magnet must always penetrate the stator. This leads to a high current device that can inject >1 kA into a series-connected HTS coil at 53 K. The open-circuit DC output voltage (Voc) from this HTS dynamo has been studied at stator temperatures between 35 and 95 K and attained a maxima at a temperature ∼5 K lower than the stator Tc. At lower temperatures, Voc decreases and falls to zero below ∼40 K. This non-intuitive effect is found to be due to flux-screening by critical currents flowing with the HTS stator, which increase with decreasing temperature. These shielding currents prevent flux from penetrating the HTS stator and, hence, reduce the magnitude of locally induced emf (and thus DC output) within the HTS film. A key implication of these results is that all magnetically driven HTS flux pumps should be operated at temperatures well above their flux-screening point, and this consideration must be taken into account for future designs of multi-kA class HTS flux pumps. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) non-insulated (NI) coils have the unique capability to bypass current through conductive turn-to-turn contacts, mitigating the possibility of a catastrophic failure in the event of a quench. However, this turn-to-turn conductivity leads to a significant increase in the coil decay/charging time constant. To understand this phenomenon, several modeling techniques have been proposed, including the lumped and distributed network (DN) circuit models, and more recently the finite-element (FE) models. In this paper, the decay results obtained from modeling HTS NI pancake coils using both a DN model and a 2D FE model approach are evaluated and compared. Steady-state fields, and transient charging and decay behaviors are calculated with each model and the results compared. Key differences are highlighted, including the computation speed and the capturing of various physical phenomena. Both models exhibit non-exponential decay during initial coil discharge due to current redistribution between the inner and outer turns. In addition, the FE model exhibits other effects arising from current redistribution in both the radial and axial directions, including remanent magnetization, and variation of the "apparent total inductance" during charging. Simulations of sudden discharge have also been analyzed using the common "lumped circuit" formula. This shows that extracted values for the apparent surface contact resistance between coil windings can differ by more than a factor of 5 from the initial input value. Our results confirms the optimal choice of architecture for future NI coil models and emphasize that caution should be exercised when interpreting experimental results using the lumped circuit approach. [ABSTRACT FROM AUTHOR]