Construction and measurement of the pre-series twin aperture resistive quadrupole magnet for the LHC beam cleaning insertions

CERN's Large Hadron Collider (LHC) requires 48 twin aperture resistive quadrupoles in the beam cleaning insertions. Canada is contributing these magnets to CERN in the framework of the TRIUMF-LHC collaboration contracts. A pre-series magnet was produced by Canadian industry and delivered in March 2001. This magnet incorporates important design changes that resulted from experience with a prototype magnet. The construction of this pre-series magnet and the measurements made at ALSTOM and at CERN are reported. A comparison is made between high precision pole distance measurements and the magnetic measurements performed with a rotating coil mole. Conclusions for series production and possibilities for multipole corrections are outlined.     

Microstructure coarsening during static annealing of 60Sn40Pb solder joints: II eutectic coarsening kinetics

The eutectic coarsening kinetics for 60Sn40Pb solder joints annealed at 50°C to 150° C was determined to be of the form

Multiview deblurring for 3-D images from light-sheet-based fluorescence microscopy

We propose an algorithm for 3-D multiview deblurring using spatially variant point spread functions (PSFs). The algorithm is applied to multiview reconstruction of volumetric microscopy images. It includes registration and estimation of the PSFs using irregularly placed point markers (beads). We formulate multiview deblurring as an energy minimization problem subject to L1-regularization. Optimization is based on the regularized Lucy-Richardson algorithm, which we extend to deal with our more general model. The model parameters are chosen in a profound way by optimizing them on a realistic training set. We quantitatively and qualitatively compare with existing methods and show that our method provides better signal-to-noise ratio and increases the resolution of the reconstructed images.     

A model for the complex permittivity of water at frequencies below 1 THz

Experimental permittivity data of liquid water, compiled from the open literature, were selectively applied to support a modeling strategy. Frequencies up to 1 THz and atmospheric temperatures are covered with an expression made up by two relaxation (Debye) terms. The double-Debye model reduces to one term when the high frequency limit is set at 100 GHz, and the model can be extended to 30 THz by adding two resonance (Lorentzian) terms. The scheme was carried out by employing nonlinear least-squares fitting routines to data we considered reliable.     

Microstructure coarsening during static annealing of 60Sn40Pb solder joints: III intermetallic compound growth kientics

The growth of the total (Cu₃Sn+Cu₆Sn) intermetallic compound layer in Cu-60Sn40Pb solder joints during static annealing at 50°C to 150°C was described by the equation hi=h_o+A_o exp(−Q_a/RT)t^p with h_o=0–0.3 μm, p=0.38–0.70, A_o=1.9×10⁻⁴–3.4×10⁻⁴ m/s^p, and Q_a=25.5–30.9 kJ/mole. These constants are within the range of those obtained by others and give values of D_o and Q which are in reasonable accord with those for the diffusion coefficients in Cu₃Sn and Cu₆Sn₅ determined in diffusion couples. The deviation of the values of the time exponent p from the ideal of 0.5 for diffusion growth may be due to inaccuracies or errors pertaining to the measured thickness (especially h_o) and the complex nature of the diffusion process.     

Integration of InGaP/GaAs/Ge triple‐junction solar cells on deeply patterned silicon substrates

We report preliminary results on InGaP/InGaAs/Ge photovoltaic cells for concentrated terrestrial applications, monolithically integrated on engineered Si(001) substrates. Cells deposited on planar Ge/Si(001) epilayers, grown by plasma‐enhanced chemical vapor deposition, provide good efficiency and spectral response, despite the small thickness of the Ge epilayers and a threading dislocation density as large as 10⁷/cm². The presence of microcracks generated by the thermal misfit is compensated by a dense collection grid that avoids insulated areas. In order to avoid the excessive shadowing introduced by the use of a dense grid, the crack density needs to be lowered. Here, we show that deep patterning of the Si substrate in blocks can be an option, provided that a continuous Ge layer is formed at the top, and it is suitably planarized before the metalorganic chemical vapor deposition. The crack density is effectively decreased, despite that the efficiency is also lowered with respect to unpatterned devices. The reasons of this efficiency reduction are discussed, and a strategy for improvement is proposed and explored. Full morphological analysis of the coalesced Ge blocks is reported, and the final devices are tested under concentrated AM1.5D spectrum. Copyright © 2016 John Wiley & Sons, Ltd.     

Qualitative and quantitative evaluation of heart sound reduction from lung sound recordings

Recursive least squares (RLS) adaptive noise cancellation (ANC) and wavelet transform (WT) ANC have been applied and compared for heart sound (HS) reduction from lung sounds (LS) recordings. Novel processes for quantitative and qualitative evaluation of any method for HS reduction from LS have also been proposed.     

On the search for low correlated binary sequences

The construction of binary sequences with low aperiodic correlation is one of the most famous, but also one of the most challenging, problems in signal design theory. In recent decades, many approaches from different mathematical disciplines have been used to tackle the problem. This paper summarizes the known results and adds some new results on the peak correlation of extended Legendre sequences and on binary arrays.     

Endurance behavior of conductive yarns

Various companies are industrializing ‘photonic’ textiles for medical and architectural applications. Here we report reliability testing of photonic textiles based on woven textiles with integrated copper-based conductive yarns used to drive attached LEDs. These textiles were subjected to cyclic mechanical stress tests and the cycle life was analyzed in terms of fatigue. Results show that failure is due to wire fractures at the transition from the rigid component to the compliant textile. The results are in good agreement with Cu-fatigue data from literature. This shows that it is possible to estimate the lifetime of electronic textiles under use conditions by the mechanical fatigue of the conducting yarn material properties.