11,042 research outputs found
Nonlinear waves in heterogeneous elastic rods via homogenization
We consider the propagation of a planar loop on a heterogeneous elastic rod with a periodic microstructure consisting of two alternating homogeneous regions with different material properties. The analysis is carried out using a second-order homogenization theory based on a multiple scale asymptotic expansion
Analysis of the Inter-basin Water Transfer Scheme in India: a case study of the Godavari-Krishna link
River basin managementRiver basin developmentDevelopment projectsWater availab ilityWater demandWater transferDamsCanalsCrop management
Axial GaAs/Ga(As,Bi) Nanowire Heterostructures
Bi-containing III-V semiconductors constitute an exciting class of metastable
compounds with wide-ranging potential optoelectronic and electronic
applications. However, the growth of III-V-Bi alloys requires group-III-rich
growth conditions, which pose severe challenges for planar growth. In this
work, we exploit the naturally-Ga-rich environment present inside the metallic
droplet of a self-catalyzed GaAs nanowire to synthesize metastable
GaAs/GaAsBi axial nanowire heterostructures with
high Bi contents. The axial GaAsBi segments are
realized with molecular beam epitaxy by first enriching only the
vapor-liquid-solid (VLS) Ga droplets with Bi, followed by exposing the
resulting Ga-Bi droplets to As at temperatures ranging from 270 to
380\,^{\circ}C to precipitate GaAsBi only under
the nanowire droplets. Microstructural and elemental characterization reveals
the presence of single crystal zincblende GaAsBi
axial nanowire segments with Bi contents up to (102). This work
illustrates how the unique local growth environment present during the VLS
nanowire growth can be exploited to synthesize heterostructures with metastable
compounds
A Securities Lawyer\u27s Dilemma: The SEC\u27s Policy of Disclosure v. the Attorney-Client Privilege
This comment discusses the possible conflicts between the attorney-client privilege and the Securities Exchange Commission\u27s requirements. The author begins by examining the National Student Marketing litigation, which reflects a new role for securities lawyers and a new SEC policy in enforcing this role. The author then discusses the basic premises underlying the SEC\u27s imposition of a duty on a lawyer to disclose client conduct. The author concludes that the issue remains unsettled, but that the privilege is in danger unless the legal profession can convince the courts that maintaining confidences has a positive effect on compliance with the law
Ballistic Localization in Quasi-1D Waveguides with Rough Surfaces
Structure of eigenstates in a periodic quasi-1D waveguide with a rough
surface is studied both analytically and numerically. We have found a large
number of "regular" eigenstates for any high energy. They result in a very slow
convergence to the classical limit in which the eigenstates are expected to be
completely ergodic. As a consequence, localization properties of eigenstates
originated from unperturbed transverse channels with low indexes, are strongly
localized (delocalized) in the momentum (coordinate) representation. These
eigenstates were found to have a quite unexpeted form that manifests a kind of
"repulsion" from the rough surface. Our results indicate that standard
statistical approaches for ballistic localization in such waveguides seem to be
unappropriate.Comment: 5 pages, 4 figure
Multi-terminal HVDC grids with inertia mimicry capability
The high-voltage multi-terminal dc (MTDC) systems are foreseen to experience an important development in the next years. Currently, they have appeared to be a prevailing technical and economical solution for harvesting offshore wind energy. In this study, inertia mimicry capability is added to a voltage-source converter-HVDC grid-side station in an MTDC grid connected to a weak ac grid, which can have low inertia or even operate as an islanded grid. The presented inertia mimicry control is integrated in the generalised voltage droop strategy implemented at the primary level of a two-layer hierarchical control structure of the MTDC grid to provide higher flexibility, and thus controllability to the network. Besides, complete control framework from the operational point of view is developed to integrate the low-level control of the converter stations in the supervisory control centre of the MTDC grid. A scaled laboratory test results considering the international council on large electric systems (CIGRE) B4 MTDC grid demonstrate the good performance of the converter station when it is connected to a weak islanded ac grid.Peer ReviewedPostprint (author's final draft
Evaluation of Cache Inclusion Policies in Cache Management
Processor speed has been increasing at a higher rate than the speed of memories over the last years. Caches were designed to mitigate this gap and, ever since, several cache management techniques have been designed to further improve performance.
Most techniques have been designed and evaluated on non-inclusive caches even though many modern processors implement either inclusive or exclusive policies. Exclusive caches benefit from a larger effective capacity, so they might become more popular when the number of cores per last-level cache increases.
This thesis aims to demonstrate that the best cache management techniques for exclusive caches do not necessarily have to be the same as for non-inclusive or inclusive caches. To assess this statement we evaluated several cache management techniques with different inclusion policies, number of cores and cache sizes.
We found that the configurations for inclusive and non-inclusive policies usually performed similarly, but for exclusive caches the best configurations were indeed different. Prefetchers impacted performance more than replacement policies, and determined which configurations were the best ones. Also, exclusive caches showed a higher speedup on multi-core.
The least recently used (LRU) replacement policy is among the best policies for any prefetcher combination in exclusive caches but is the one used as a baseline in most cache replacement policy research. Therefore, we conclude that the results in this thesis motivate further research on prefetchers and replacement policies targeted
to exclusive caches
- âŠ