Time-aging time-stress superposition in soft glass under tensile deformation field

We have studied the tensile deformation behaviour of thin films of aging aqueous suspension of Laponite, a model soft glassy material, when subjected to a creep flow field generated by a constant engineering normal stress. Aqueous suspension of Laponite demonstrates aging behaviour wherein it undergoes time dependent enhancement of its elastic modulus as well as its characteristic relaxation time. However, under application of the normal stress, the rate of aging decreases and in the limit of high stress, the aging stops with the suspension now undergoing a plastic deformation. Overall, it is observed that the aging that occurs over short creep times at small normal stresses is same as the aging that occurs over long creep times at large normal stresses. This observation allows us to suggest an aging time - process time - normal stress superposition principle, which can predict rheological behaviour at longer times by carrying out short time tests.Comment: 26 pages, 7 figures, To appear in Rheologica Act

TIRAMISU: A Polyhedral Compiler for Expressing Fast and Portable Code

This paper introduces TIRAMISU, a polyhedral framework designed to generate high performance code for multiple platforms including multicores, GPUs, and distributed machines. TIRAMISU introduces a scheduling language with novel commands to explicitly manage the complexities that arise when targeting these systems. The framework is designed for the areas of image processing, stencils, linear algebra and deep learning. TIRAMISU has two main features: it relies on a flexible representation based on the polyhedral model and it has a rich scheduling language allowing fine-grained control of optimizations. TIRAMISU uses a four-level intermediate representation that allows full separation between the algorithms, loop transformations, data layouts, and communication. This separation simplifies targeting multiple hardware architectures with the same algorithm. We evaluate TIRAMISU by writing a set of image processing, deep learning, and linear algebra benchmarks and compare them with state-of-the-art compilers and hand-tuned libraries. We show that TIRAMISU matches or outperforms existing compilers and libraries on different hardware architectures, including multicore CPUs, GPUs, and distributed machines

Correction of sagittal plane deformity and predictive factors for a favourable radiological outcome following multilevel posterior lumbar interbody fusion for mild degenerative scoliosis

Purpose Limited data is available in the literature on the radiographic results of multilevel posterior lumbar interbody fusion (MPLIF) in the treatment of degenerative scoliosis. The objective of our study was to evaluate the segmental and global correction achieved with MPLIF in the treatment of degenerative scoliosis. Methods Between 2009 and 2014, 42 patients underwent correction of degenerative scoliosis with MPLIF. Several radiological parameters were measured pre- and post-operatively by two independent observers. A statistical analysis was performed to assess the inter-observer reliability of the measurements and to determine the degree of segmental correction achieved at each intervertebral disc. Using sagittal vertical axis (SVA) less than 47 mm; lumbar lordosis (LL) within 11° of pelvic incidence (PI); and pelvic tilt (PT) no more than 22° as radiological criteria for procedural acceptability, we determined predictive factors for a favourable radiological outcome. Results Forty-two patients (34 female) were included in our study. The average amount of correction per segment was 6.2°. The overall correction achieved with MPLIF was 16.6°. Twenty-six of the 42 patients (61.9 %) had post-operative SVA values less than 47 mm. Nineteen of the 42 patients (45.2 %) had average post-operative LL within 11° of the PI. Sixteen of the 42 patients (38.1 %) had PT less than 22°. Younger age, female gender and a low pre-operative PT were significantly associated with the attainment of a satisfactory sagittal alignment. Conclusion Our results demonstrate that a satisfactory correction can be achieved in degenerative scoliosis with MPLIF. In addition, our results show that it is significantly more likely to achieve a satisfactory radiological outcome in younger, female patients with low pre-operative PT