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A review of microgrid development in the United States – A decade of progress on policies, demonstrations, controls, and software tools
Microgrids have become increasingly popular in the United States. Supported by favorable federal and local policies, microgrid projects can provide greater energy stability and resilience within a project site or community. This paper reviews major federal, state, and utility-level policies driving microgrid development in the United States. Representative U.S. demonstration projects are selected and their technical characteristics and non-technical features are introduced. The paper discusses trends in the technology development of microgrid systems as well as microgrid control methods and interactions within the electricity market. Software tools for microgrid design, planning, and performance analysis are illustrated with each tool's core capability. Finally, the paper summarizes the successes and lessons learned during the recent expansion of the U.S. microgrid industry that may serve as a reference for other countries developing their own microgrid industries
STR-875: PREDICTING FAILURE IN SLIDING ISOLATION BEARINGS UNDER LONG-PERIOD MOTIONS
For the majority of structural systems, there has been a push to understand collapse behaviour and to quantify collapse margin ratios. However, for seismic isolation there is still significant work to be done in this area, especially for sliding bearings, for which little research on failure has been investigated. While it may be the goal of the designer that isolation bearing capacity is not reached, for performance based design it is essential to understand how and under what levels the bearing will fail. To investigate failure, a model based on the theory of rigid body kinematics, rigid body dynamics and contact mechanics is employed with an added parallel non-linear damper to explicitly consider the energy dissipation. Ricker pulses are extracted from long period motions and used to predict whether the bearing impacts and if that impact results in failure. The research finds that these pulses are good predictors providing that the extracted pulse periods are sufficiently long (greater than 0.5 s); otherwise the pulse does not dominate the response of the bearing. Generalized graphs are produced for use in predicting bearing performance and collapse margin ratio (assuming a rigid superstructure) at initial stages of design
Study the Heavy Molecular States in Quark Model with Meson Exchange Interaction
Some charmonium-like resonances such as X(3872) can be interpreted as
possible molecular states. Within the quark model, we study
the structure of such molecular states and the similar
molecular states by taking into account of the light meson exchange (,
, , and ) between two light quarks from different
mesons
Low-lying S-wave and P-wave Dibaryons in a Nodal Structure Analysis
The dibaryon states as six-quark clusters of exotic QCD states are
investigated in this paper. With the inherent nodal surface structure analysis,
the wave functions of the six-quark clusters (in another word, the dibaryons)
are classified. The contribution of the hidden color channels are discussed.
The quantum numbers of the low-lying dibaryon states are obtained. The States
, ,
, and the
hidden color channel states with the same quantum numbers are proposed to be
the candidates of dibaryons, which may be observed in experiments.Comment: 29 pages, 2 figure
First-principles calculations of phase transition, low elastic modulus, and superconductivity for zirconium
The elasticity, dynamic properties, and superconductivity of ,
, and Zr are investigated by using first-principles methods.
Our calculated elastic constants, elastic moduli, and Debye temperatures of
and phases are in excellent agreement with experiments.
Electron-phonon coupling constant and electronic density of states at
the Fermi level (\emph{E}) are found to increase with pressure
for these two hexagonal structures. For cubic phase, the critical
pressure for mechanical stability is predicted to be 3.13 GPa and at \emph{P}=4
GPa the low elastic modulus (=31.97 GPa) can be obtained. Besides, the
critical pressure for dynamic stability of phase is achieved by phonon
dispersion calculations to be 26 GPa. Over this pressure,
and (\emph{E}) of phase decrease upon further
compression. Our calculations show that the large value of superconducting
transition temperature \emph{T}_{\rm{c}} at 30 GPa for Zr is mainly
due to the TA1 soft mode. Under further compression, the soft vibrational mode
will gradually fade away.Comment: 15 pages, 5 figure
Coherently photo-induced ferromagnetism in diluted magnetic semiconductors
Ferromagnetism is predicted in undoped diluted magnetic semiconductors
illuminated by intense sub-bandgap laser radiation . The mechanism for
photo-induced ferromagnetism is coherence between conduction and valence bands
induced by the light which leads to an optical exchange interaction. The
ferromagnetic critical temperature T_C depends both on the properties of the
material and on the frequency and intensity of the laser and could be above 1
K.Comment: 11 pages, 2 figures, preprint styl
Theory for Phase Transitions in Insulating Vanadium Oxide
We show that the recently proposed S=2 bond model with orbital degrees of
freedom for insulating VO not only explains the anomalous magnetic
ordering, but also other mysteries of the magnetic phase transition. The model
contains an additional orbital degree of freedom that exhibits a zero
temperature quantum phase transtion in the Ising universality class.Comment: 5 pages, 2 figure
Quantum size effects on the perpendicular upper critical field in ultra-thin lead films
We report the thickness-dependent (in terms of atomic layers) oscillation
behavior of the perpendicular upper critical field in the
ultra-thin lead films at the reduced temperature (). Distinct
oscillations of the normal-state resistivity as a function of film thickness
have also been observed. Compared with the oscillation, the
shows a considerable large oscillation amplitude and a phase shift. The
oscillatory mean free path caused by quantum size effect plays a role in
oscillation.Comment: 4 pages, 4 figure
Demonstrating Additional Law of Relativistic Velocities based on Squeezed Light
Special relativity is foundation of many branches of modern physics, of which
theoretical results are far beyond our daily experience and hard to realized in
kinematic experiments. However, its outcomes could be demonstrated by making
use of convenient substitute, i.e. squeezed light in present paper. Squeezed
light is very important in the field of quantum optics and the corresponding
transformation can be regarded as the coherent state of SU(1; 1). In this
paper, the connection between the squeezed operator and Lorentz boost is built
under certain conditions. Furthermore, the additional law of relativistic
velocities and the angle of Wigner rotation are deduced as well
Magnetic Structure of Heavy Fermion Ce2RhIn8
Magnetic structure of the heavy fermion antiferromagnet Ce2RhIn8 is
determined using neutron diffraction.Comment: 4 pages, 3 figures, 1 tabl
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