9,574 research outputs found
Piezoelectric devices for vibration suppression: Modeling and application to a truss structure
For a space structure assembled from truss members, an effective way to control the structure may be to replace the regular truss elements by active members. The active members play the role of load carrying elements as well as actuators. A piezo strut, made of a stack of piezoceramics, may be an ideal active member to be integrated into a truss space structure. An electrically driven piezo strut generates a pair of forces, and is considered as a two-point actuator in contrast to a one-point actuator such as a thruster or a shaker. To achieve good structural vibration control, sensing signals compatible to the control actuators are desirable. A strain gage or a piezo film with proper signal conditioning to measure member strain or strain rate, respectively, are ideal control sensors for use with a piezo actuator. The Phase 0 CSI Evolutionary Model (CEM) at NASA Langley Research Center used cold air thrusters as actuators to control both rigid body motions and flexible body vibrations. For the Phase 1 and 2 CEM, it is proposed to use piezo struts to control the flexible modes and thrusters to control the rigid body modes. A tenbay truss structure with active piezo struts is built to study the modeling, controller designs, and experimental issues. In this paper, the tenbay structure with piezo active members is modelled using an energy method approach. Decentralized and centralized control schemes are designed and implemented, and preliminary analytical and experimental results are presented
Partially composite 2-Higgs-doublet model
In the extra dimensional scenarios with gauge fields in the bulk, the
Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type
attractive four-fermion interactions, which can break electroweak symmetry
dynamically with accompanying composite Higgs fields. We consider a possibility
that electroweak symmetry breaking (EWSB) is triggered by both a fundamental
Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism
induced by a new strong dynamics. The resulting Higgs sector is a partially
composite two-Higgs doublet model with specific boundary conditions on the
coupling and mass parameters originating at a compositeness scale .
The phenomenology of this model is discussed including the collider
phenomenology at LHC and ILC.Comment: To appear in the proceeding of LCWS06, Bangalore, Indi
Helstrom Theorem by No-Signaling Condition
We prove a special case of Helstrom theorem by using no-signaling condition
in the special theory of relativity that faster-than-light communication is
impossible.Comment: Minor corrections (A reference added, discussion part deleted, typos
in equations corrected), 2 pages, RevTe
Quantum Key Distribution with High Loss: Toward Global Secure Communication
We propose a decoy-state method to overcome the photon-number-splitting
attack for Bennett-Brassard 1984 quantum key distribution protocol in the
presence of high loss: A legitimate user intentionally and randomly replaces
signal pulses by multi-photon pulses (decoy-states). Then they check the loss
of the decoy-states. If the loss of the decoy-states is abnormally less than
that of signal pulses, the whole protocol is aborted. Otherwise, to continue
the protocol, they estimate loss of signal multi-photon pulses based on that of
decoy-states. This estimation can be done with an assumption that the two
losses have similar values, that we justify.Comment: derivation made more detailed, 4 pages, RevTe
Discovery From Non-Parties (Third-Party Discovery) in International Arbitration
International arbitration rules and many arbitration laws usually provide procedures that permit tribunals to order parties to disclose documents and other materials to the other parties.1 More complex are the rules that determine opportunities to obtain discovery from persons that are not party to the arbitration (third-party discovery). This article will review third-party discovery under the Federal Arbitration Act (FAA) and the provisions of the US Code s.1782 that authorise US courts to act in aid of actions before foreign tribunals. Section 1782 has unique interest at this time because it figured prominently in the EU antitrust investigation of Intel that was initiated on request from Advanced Micro Devices (AMD). Early in that investigation, AMD filed a s.1782 request in the US District Court to obtain evidence from US sources for submission to the DG-Competition of the European Commission (EC). This request ultimately led to the Supreme Court’s decision in Intel Corp v Advanced Micro Devices Inc2 which appeared to significantly expand the scope of s.1782. Ironically, after AMD won on key legal issues in the Supreme Court, the District Court on remand exercised its discretion and denied the request for judicial assistance. This paper first describes the FAA non-party discovery rules and the split among the federal appellate courts concerning the authority of arbitrators to order prehearing discovery from non-parties. Next, it provides an analysis of the meaning of the terms “interested party” and “tribunal”—terms that were controversially interpreted by the Supreme Court in Intel and are essential to the application of s.1782. Finally, it discusses the “discretionary” factors used by the federal courts in deciding whether to grant a s.1782 request even when the statutory criteria are met. The opportunity to exercise this discretion seems to rebut the argument that the Supreme Court’s interpretation of s.1782 gives participants before foreign tribunals more discovery rights in the United States than are available to the parties in arbitrations covered by the FAA
Calcium Metabolism and Egg Shell Quality in Laying Hens
This experiment was designed to determine whether diet alterations that cause a somewhat reduced rate of lay could influence shell quality and whether certain chemical and biochemical measurements could be related to a decline in shell quality
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