Measurements and calculations of transport AC loss in second generation high temperature superconducting pancake coils

Theoretical and experimental AC loss data on a superconducting pancake coil wound using second generation (2 G) conductors are presented. An anisotropic critical state model is used to calculate critical current and the AC losses of a superconducting pancake coil. In the coil there are two regions, the critical state region and the subcritical region. The model assumes that in the subcritical region the flux lines are parallel to the tape wide face. AC losses of the superconducting pancake coil are calculated using this model. Both calorimetric and electrical techniques were used to measure AC losses in the coil. The calorimetric method is based on measuring the boil-off rate of liquid nitrogen. The electric method used a compensation circuit to eliminate the inductive component to measure the loss voltage of the coil. The experimental results are consistent with the theoretical calculations thus validating the anisotropic critical state model for loss estimations in the superconducting pancake coil

Evaluation of biophysical, anatomical and biochemical traits of resistance to Sitophilus oryzae L (Coleoptera: Curculionidae) in stored maize

Sitophilus oryzae L is the most destructive insect pest of stored maize and is widely distributed in tropical regions. In the present study, eighteen maize genotypes were screened for several susceptibility parameters against S. oryzae by using «No Choice method». Biophysical traits (test weight, thousand kernel weight, kernel hardness), anatomical fractions (tip cap, germ, pericarp, endosperm), biochemical variants (starch, protein, oil, sugar) were correlated with insect susceptibility parameters. There is significant relationship among test weight, kernel hard- ness, and insect susceptibility parameters. Pericarp was positively correlated while endosperm, starch content were negatively correlated with median development period but were non-significant. Majority of the maize geno- types containing harder kernels and thick pericarp showed less susceptibility to S. oryzae. The results indicated that the biophysical, anatomical and biochemical traits are responsible for varying levels of resistance to S. oryzae

Effect of wire drawing and cold rolling on the precursor 2212 phase texture and its subsequent influence on the (Bi,Pb)2Sr2Ca2Cu3Ox texture in Ag-clad tapes

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Transport AC Loss Measurements of a Triangular, Epoxy-Impregnated High Temperature Superconducting (HTS) Coil

In this paper, the transport AC losses in a triangular, epoxy-impregnated high temperature superconducting (HTS) coil made from YBCO coated conductor, intended for use in a prototype axial flux HTS electric machine, are measured using two different electrical techniques at 77 K. The first set of AC loss measurements of the coil are carried out at the University of Cambridge using a technique based on a lock-in amplifier. The coil is then measured at the Center for Advanced Power Systems (CAPS), Florida State University, using a technique based on a high accuracy data acquisition (DAQ) measurement system. The two different methods show consistent results, validating the accuracy of these two techniques for transport AC loss measurements of superconducting coils. Multiple voltage taps are utilized within the coil to study the details and distribution of the AC loss in different sections of the coil. Losses are also measured with a flux diverter made of ferromagnetic material to analyze its effect on the AC losses