Numerical modelling of an imping jet

Impinging flow occurs when a fluid impacts a comparatively solid boundary upon which divergence occurs. A perfect example of an impinging flow is the impact and divergence of air at ground level during a thunderstorm outflow. The importance of modelling thunderstorm outflows, and in particular the downburst is now well-known to the wind engineering community and research into many of its characteristics is underway throughout the world. The reader is directed to the text by Fujita [I] for an introduction to downburst concepts and theory.

Tornado Damage Assessment in the aftermath of the May 20th 2013 Moore Oklahoma Tornado

This report presents observations, findings, and recommendations from an engineering reconnaissance trip following the May 20th, 2013 tornado that struck Moore, Oklahoma. A team of faculty, research scientists, professional engineers, and civil engineering students were tasked with investigating and documenting the performance of critical facility buildings and residences, (IBC Occupancy Category II, III, and IV), in Moore, OK. The Enhanced Fujita (EF) 5 tornado created a 17-mile long damage swath destroying over 12,000 buildings and killing 24 people. The total economic loss from this single event was estimated at $3 billion. The May 20th tornado was the third major tornado to hit Moore in the previous 15 years.

A promoter-level mammalian expression atlas

Regulated transcription controls the diversity, developmental pathways and spatial organization of the hundreds of cell types that make up a mammal. Using single-molecule cDNA sequencing, we mapped transcription start sites (TSSs) and their usage in human and mouse primary cells, cell lines and tissues to produce a comprehensive overview of mammalian gene expression across the human body. We find that few genes are truly 'housekeeping', whereas many mammalian promoters are composite entities composed of several closely separated TSSs, with independent cell-type-specific expression profiles. TSSs specific to different cell types evolve at different rates, whereas promoters of broadly expressed genes are the most conserved. Promoter-based expression analysis reveals key transcription factors defining cell states and links them to binding-site motifs. The functions of identified novel transcripts can be predicted by coexpression and sample ontology enrichment analyses. The functional annotation of the mammalian genome 5 (FANTOM5) project provides comprehensive expression profiles and functional annotation of mammalian cell-type-specific transcriptomes with wide applications in biomedical research.

“Post silicon debug of SOC designs”

Continuous advances in VLSI technology have made implementation of very complicated systems possible. Modern System-on -Chips (SoCs) have many processors, IP cores and other functional units. As a result, complete verification of whole systems before implementation is becoming infeasible; hence it is likely that these systems may have some errors after manufacturing. This increases the need to find design errors in chips after fabrication. The main challenge for post-silicon debug is the observability of the internal signals. Post-silicon debug is the problem of determining what's wrong when the fabricated chip of a new design behaves incorrectly. This problem now consumes over half of the overall verification effort on large designs, and the problem is growing worse.Traditional post-silicon debug methods concentrate on functional parts of systems and provide mechanisms to increase the observability of internal state of systems. Those methods may not be sufficient as modern SoCs have lots of blocks (processors, IP cores, etc.) which are communicating with one another and communication is another source of design errors. This tutorial will be provide an insight into various observability enhancement techniques, on chip instrumentation techniques and use of high level models to support the debug process targeting both inside blocks and communication among them. It will also cover the use of formal methods to help debug process.

The State and Fate of Himalayan Glaciers

Himalayan glaciers are a focus of public and scientific debate. Prevailing uncertainties are of major concern because some projections of their future have serious implications for water resources. Most Himalayan glaciers are losing mass at rates similar to glaciers elsewhere, except for emerging indications of stability or mass gain in the Karakoram. A poor understanding of the processes affecting them, combined with the diversity of climatic conditions and the extremes of topographical relief within the region, makes projections speculative. Nevertheless, it is unlikely that dramatic changes in total runoff will occur soon, although continuing shrinkage outside the Karakoram will increase the seasonality of runoff, affect irrigation and hydropower, and alter hazards.

SEU Tolerant Robust Memory Cell Design

The implementation of semiconductor circuits and systems in nano-technology makes it possible to achieve high speed, lower voltage level and smaller area. The unintended and undesirable result of this scaling is that it makes integrated circuits susceptible to soft errors normally caused by alpha particle or neutron hits. These events of radiation strike resulting into bit upsets referred to as single event upsets(SEU), become increasingly of concern for the reliable circuit operation in the field. Storage elements are worst hit by this phenomenon. As we further scale down, there is greater interest in reliability of the circuits and systems, apart from the performance, power and area aspects. In this paper we propose an improved 12T SEU tolerant SRAM cell design. The proposed SRAM cell is economical in terms of area overhead. It is easy to fabricate as compared to earlier designs. Simulation results show that the proposed cell is highly robust, as it does not flip even for a transient pulse with 62 times the Q(crit) of a standard 6T SRAM cell.

Periodic nanovoid structures via femtosecond laser irradiation

We have observed periodically aligned nanovoid structures inside a conventional borosilicate glass induced by a single femtosecond (fs) laser beam for the first time, to our knowledge. The spherical voids of nanosized diameter were aligned spontaneously with a period along the propagation direction of the laser beam. The period, the number of voids, and the whole length of the aligned void structure were controlled by changing the laser power, the pulse number, and the position of the focal point.

Photoreduction of Ag+ in aluminoborate glasses induced by irradiation of a femtosecond laser

We report on photoreduction of Ag+ in aluminoborate glasses induced by irradiation of a femtosecond laser. Novel fluorescence was observed in the femtosecond laser irradiated glass when excited by a 365 nm ultraviolet lamp. Optical absorption, emission, and electron spin resonance spectra of the glass samples demonstrated that after the laser irradiation, portions of silver ions near the focused part of the laser beam inside the glass were reduced to silver atoms, which resulted in the formation of the characteristic fluorescence. The observed phenomenon may have promising applications in the fabrication of functional optical devices.