Differential Astrometry of Sub-arcsecond Scale Binaries at the Palomar Testbed Interferometer

We have used the Palomar Testbed Interferometer to perform very high precision differential astrometry on the 0.25 arcsecond separation binary star HD 171779. In 70 minutes of observation we achieve a measurement uncertainty of approximately 9 micro-arcseconds in one axis, consistent with theoretical expectations. Night-to-night repeatability over four nights is at the level of 16 micro-arcseconds. This method of very-narrow-angle astrometry may be extremely useful for searching for planets with masses as small as 0.5 Jupiter Masses around a previously neglected class of stars -- so-called ``speckle binaries.'' It will also provide measurements of stellar parameters such as masses and distances, useful for constraining stellar models at the 10^-3 level.Comment: 19 pages including 6 figures. Submitted to ApJ. Typos corrected, several parts reworded for clarificatio

Exchange Rates and Monetary Policy in Emerging Market Economies

This paper investigates the effects of exchange rate regimes and alternative monetary policy rules for an emerging market economy that is subject to a volatile external environment in the form of shocks to world interest rates and the terms of trade. In particular, we highlight the impact of financial frictions and the degree of exchange rate pass through in determining the relative performance of alternative regimes in stablizing the economy in the face of external shocks. Our results are quite sharp. When exchange rate pass-through is high, a policy of non-traded goods inflation targeting does best in stablizing the economy, and is better in welfare terms. When exchange rate pass-through is low, however, a policy of strict CPI inflation targeting is better. In all cases, a fixed exchange rate is undesirable. In addition, financial frictions have no implications for the ranking of alternative policy rules.

Exchange Rates and Monetary Policy in Emerging Market Economies

This paper investigates the effects of exchange rate regimes and alternative monetary policy rules for an emerging market economy that is subject to a volatile external environment in the form of shocks to world interest rates and the terms of trade. In particular, we highlight the impact of financial frictions and the degree of exchange rate pass through in determining the relative performance of alternative regimes in stablizing the economy in the face of external shocks. Our results are quite sharp. When exchange rate pass-through is high, a policy of non-traded goods inflation targeting does best in stablizing the economy, and is better in welfare terms. When exchange rate pass-through is low, however, a policy of strict CPI inflation targeting is better. In all cases, a fixed exchange rate is undesirable. In addition, financial frictions have no implications for the ranking of alternative policy rules.

New strong sector, odd-parity processes, and the Tevatron

The color-octet isosinglet "rho" of a new strong-interaction sector is readily produced in ppbar collisions. Its odd-parity decay to an "eta" and a gluon may exceed its decay rate to dijets. At center of mass energies sufficiently greater than the colored "rho" mass, the odd-parity production of ("omega" + colored "eta") or ("rho" + colored "pion") may be comparable to ttbar production. Considering that the "omega" has a dominant odd-parity decay mode, we end up with (Z, W, or gamma) + 4 jet events with two of the jets containing b or bbar.Comment: 8 pages, uuencoded PS file, try ghostscript or direct printing rather than ghostview, PS file of paper without figure is available on WWW at http://bigmac2.physics.utoronto.ca/BHpapers.htm

Charge assignments in multiple-U(1) gauge theories

We discuss the choice of gauge field basis in multiple-U(1) gauge theories. We find that there is a preferred basis, specified by the charge orthogonality condition, in which the U(1) gauge fields do not mix under one-loop renormalization group running.Comment: 7 pages, LaTe

Investigation of Solution Verification and Validation of Nuclear Thermal Hydraulics Computational Fluid Dynamics Using Twin Rectangular Turbulent Jets

The research and development of advanced nuclear reactors requires complementary experimental and computational approaches. These approaches are used in such a manner that experimental campaigns help validate computational tools. These computational tools are then utilized for similar scenarios where experimental efforts would be prohibitive due to variety of reasons including cost. Advanced reactor designs, such as sodium fast reactors, very high temperature reactors, and molten salt reactors motivate this work due to the exotic coolants used. The exotic coolants require surrogate experiments for fluids of specific thermal physical properties to mirror their properties. There are established standards of verification and validation methods that are broken up into code and solution (also known as calculational) pathways. Code verification and validation is in the realm of the code developer while solution verification and validation is in the realm of the user. The current work reported is focused on the later and tries to do so without any assumptions regarding code verification and validation. The work conducted focuses on a case study to show an alternate means of solution verification that is pursued without restrictive methods such as Grid Convergence Index and its variants. It is not meant to be a rigorous means of developing error bands (uncertainty bands) for realistic computational fluid dynamics analysis (including 3-D effects such as turbulence) though there is an attempt to do so. The sample case study provides future users an approach to determine if their computational fluid dynamics studies are sufficient without the aforementioned methods (i.e. mesh convergence without a commentary on the error bands). The case study used in this work is based on twin planar-like turbulent jets exhausting into a large volume of fluid. The two jets combine into a single turbulent free shear planar jet which can be shown through velocity, vorticity, and Reynolds stress information in the areas of interest. The simulations used to model this case are done using the computational fluid dynamics code, Star-CCM+. Based on this effort, a simple mesh convergence methodology is proposed and a solution validation analysis was conducted. The computational fluid dynamics simulations were shown to have reasonable agreement with the experimental works within the Twin Jet Water Facility. It is hoped this work will help provide an alternate pathway for code users of computational fluid dynamics tools to do simple and effective solution verification and validation

Investigation of Solution Verification and Validation of Nuclear Thermal Hydraulics Computational Fluid Dynamics Using Twin Rectangular Turbulent Jets

The research and development of advanced nuclear reactors requires complementary experimental and computational approaches. These approaches are used in such a manner that experimental campaigns help validate computational tools. These computational tools are then utilized for similar scenarios where experimental efforts would be prohibitive due to variety of reasons including cost. Advanced reactor designs, such as sodium fast reactors, very high temperature reactors, and molten salt reactors motivate this work due to the exotic coolants used. The exotic coolants require surrogate experiments for fluids of specific thermal physical properties to mirror their properties. There are established standards of verification and validation methods that are broken up into code and solution (also known as calculational) pathways. Code verification and validation is in the realm of the code developer while solution verification and validation is in the realm of the user. The current work reported is focused on the later and tries to do so without any assumptions regarding code verification and validation. The work conducted focuses on a case study to show an alternate means of solution verification that is pursued without restrictive methods such as Grid Convergence Index and its variants. It is not meant to be a rigorous means of developing error bands (uncertainty bands) for realistic computational fluid dynamics analysis (including 3-D effects such as turbulence) though there is an attempt to do so. The sample case study provides future users an approach to determine if their computational fluid dynamics studies are sufficient without the aforementioned methods (i.e. mesh convergence without a commentary on the error bands). The case study used in this work is based on twin planar-like turbulent jets exhausting into a large volume of fluid. The two jets combine into a single turbulent free shear planar jet which can be shown through velocity, vorticity, and Reynolds stress information in the areas of interest. The simulations used to model this case are done using the computational fluid dynamics code, Star-CCM+. Based on this effort, a simple mesh convergence methodology is proposed and a solution validation analysis was conducted. The computational fluid dynamics simulations were shown to have reasonable agreement with the experimental works within the Twin Jet Water Facility. It is hoped this work will help provide an alternate pathway for code users of computational fluid dynamics tools to do simple and effective solution verification and validation

Uses of the tape recorder in the elementary school.

Thesis (M.Ed.)--Boston Universit

Article 8—Investment Securities

This paper sketches some of the important provisions and reasoning back of Article 8 of the Uniform Commercial Code, which will become effective September 1, 1965. It takes the security when issued and deals with the handling of the security on the market. Nebraska, not being primarily a commercial state, has relatively little case law on the subject covered by Article 8. Hence, this article will be helpful in Nebraska in that it will make certain a number of matters now not touched by legislation or case law and will avoid the necessity of trying to weave our way among the conflicting decisions of other jurisdictions. The primary purpose of this article is to facilitate the marketability on the free market of the instruments that come within the definition of investment securities. The Code uses a new vocabulary, and definitions are scattered throughout the Act. Article 8 is divided into four parts, and is one of the shorter and perhaps less controversial articles of the Code. Part 1 contains certain definitions and a number of general matters; part 2 deals with the rights and responsibilities of the issuer; part 3 deals with the rights and obligations of successive purchasers; part 4 deals with the registration and authenticating of securities