Optimization of microsphere optical lithography for nano-patterning

We present an original approach to realistic modeling of light focusing by microsphere systems to form the photonic jets for nano-patterning of the substrates with high refractive index. In simulations we analyze the photonic jets produced by a single sphere and close-packed array of microspheres on the photoresist layer and Si substrate. We show how the lithographic profiles can be controlled by varying the exposure dose and system geometry in wide ranges of photoresist layer thicknesses and microsphere sizes. The modeling covers the entire lithographic system and accounts for the interference of focused light transmitted through the microlenses and reflected from the Si substrate. We use our approach to optimize the size of the lithographic pattern and confirm the simulation results experimentally. The suggested set of methods is rather universal and may be applied to other microlens and resist materials to minimize lithography lateral resolution.

Mansard Roofline Model: Reinforcing the Accuracy of the Roofs

Continuous enhancements and diversity in modern multi-core hardware, such as wider and deeper core pipelines and memory subsystems, bring to practice a set of hard-to-solve challenges when modeling their upper-bound capabilities and identifying the main application bottlenecks. Insightful roofline models are widely used for this purpose, but the existing approaches overly abstract the micro-architecture complexity, thus providing unrealistic performance bounds that lead to a misleading characterization of real-world applications. To address this problem, the Mansard Roofline Model (MaRM), proposed in this work, uncovers a minimum set of architectural features that must be considered to provide insightful, but yet accurate and realistic, modeling of performance upper bounds for modern processors. By encapsulating the retirement constraints due to the amount of retirement slots, Reorder-Buffer and Physical Register File sizes, the proposed model accurately models the capabilities of a real platform (average rRMSE of 5.4%) and characterizes 12 application kernels from standard benchmark suites. By following a herein proposed MaRM interpretation methodology and guidelines, speed-ups of up to 5× are obtained when optimizing real-world bioinformatic application, as well as a super-linear speedup of 18.5× when parallelized.

A hybrid system for the near real-time modeling and visualization of extreme magnitude earthquakes

<p>Among other natural hazards, the occurrence and impact of extreme magnitude earthquakes are of great interest both from the scientific and societal points of view. The scarcity of observational instrumental data for these type of events, as well as the urgent need to take mitigation measures to minimize their effects on human life and critical infrastructure have required the development of computational codes for the modeling of the propagation of these events. </p><p>Examples of the realistic modeling of the propagation of extreme magnitude earthquakes that can be achieved by the use of powerful HPC facilities and 3D finite difference Fortran codes have been presented by Cabrera et al. 2007 and Chavez et al. 2016. These large-scale scientific simulations generate vast amount of data, writing such data out to storage step-by-step is very slow and requires expensive I/O post-processing procedures for their analyses. However, the current and foreseen major advances occurring in Exascale HPC systems offer a transformational approach to the research community, as well as the possibility for the latter of contributing to the solution of urgent and complex problems that society is or will be facing in the years to come.</p><p>Taking into account the future exascale developments and in order to speed-up in situ analysis, i.e., analyze data at the same time simulations are running, in this ongoing research we present the main computational characteristics of the hybrid system we are developing for the near real-time simulation and visualization of the propagation of the realistic modeling of the 3D wave propagation of extreme magnitude earthquakes. The system is based on the updated version the staggered finite difference Fortran code 3DWPFD, coupled with an efficient visualization C++ code. The system is being developed in the hybrid HPC Miztli of UNAM, Mexico, made up of CPUs (8344 cores) + GPUs (16 NVIDIA m2090 and 8 V100). We expect to fully adapt the code for emerging hybrid Exascale architectures in the near future. Examples of the results obtained by using the hybrid system for the modeling of the propagation of the extreme magnitude Mw 8.2 earthquake occurred the 7 September 2017 in southern Mexico will be presented.</p>

Analytical modeling and numerical analysis of the effect of mosaic patterns on composite pressure vessels with dome

The aim of this work is to provide an analytical tool and numerical analysis for the optimum design of composite pressure vessels with the dome, incorporating triangular mosaic patterns. This article presents the analytical modeling involving kinematic constraints based on geodesic trajectory: the helical angle and dome thickness. The structural analysis is performed using a commercial finite element analysis tool. The results show that this new analytical method gives more accurate dome thickness than cubic spline function and Gramoll and Namiki’s methods. The incorporation of mosaic patterns based on winding kinematics provides more realistic modeling of the real stress distribution and the stress values compared to the vessel without mosaic patterns and vessels with mosaic patterns based on nongeodesic trajectories. The results have been validated and are quite promising with regard to better accuracy and safety.