Propulsion systems dispersion analysis and optimum propellant management

Propulsion systems dispersion analysis and propellant optimization method for Apollo subsystem

Numerical Analyses of Weakly Nonlinear Velocity-Density Coupling

We study evolution of various statistical quantities of smoothed cosmic density and velocity fields using N-body simulations. The parameter $C\equiv /( )$ characterizes nonlinear coupling of these two fields and determines behavior of bulk velocity dispersion as a function of local density contrast. It is found that this parameter depends strongly on the smoothing scale even in quasi-linear regimes where the skewness parameter $S_3$ is nearly constant and close to the predicted value by the second-order perturbation theory. We also analyze weakly nonlinear effects caused by an adaptive smoothing known as the gather approach.Comment: 22 pages, 4 figures, to appear in ApJ (558, Sep 10

Apollo cryogenic integrated systems program

The integrated systems program is capable of simulating both nominal and anomalous operation of the Apollo cryogenics storage system (CSS). Two versions of the program exist; one for the Apollo 14 configuration and the other for J Type Mission configurations. The program consists of two mathematical models which are dynamically coupled. A model of the CSS components and lines determines the oxygen and hydrogen flowrate from each storage tank given the tank pressures and temperatures, and the electrical power subsystem and environmental control subsystem flow demands. Temperatures and pressures throughout the components and lines are also determined. A model of the CSS tankage determines the pressure and temperatures in the tanks given the flowrate from each tank and the thermal environment. The model accounts for tank stretch and includes simplified oxygen tank heater and stratification routines. The program is currently operational on the Univac 1108 computer

Gravitational Wave Astrometry for Rapidly Rotating Neutron Stars and Estimation of Their Distances

We discuss an astrometric timing effect on data analysis of continuous gravitational waves from rapidly rotating isolated neutron stars. Special attention is directed to the possibility of determining their distances by measuring the curvature of the wave fronts. We predict that if continuous gravitational waves from an unknown neutron star with a stable rotation are detected around 1kHz within 1/3yr by initial LIGO detectors and the ellipticity parameter epsilon is smaller than 10^{-6}, the distance r to the source can be estimated with relative error \Delta r/r of \sim 10% by using the broad band configuration of advanced LIGO detectors over 3 years. By combining the observed amplitude of the waves with the estimated distance, information on the parameter $\epsilon$ can be obtained purely through gravitational wave measurements.Comment: 6 pages, 1 figure, to appear in PR

An Experimental Overview of Results Presented at SQM 2006

I have been asked to give an critical overview on the experimental results shown in the conference with a emphasis of what has been learned and the challenges that are ahead in trying to understand the physics of the strongly interacting quark-gluon plasma. I will not try to summarize all of the results presented, rather I will concentrate primarily on RHIC data from this conference. Throughout this summary, I will periodically review some of the previous results for those not familiar with the present state of the field.Comment: 15 pages, 12 Figure

Pengalaman dan Perilaku Keluhan Konsumen yang Terpendam: Studi Fenomenologi

Tempo.co/read/news/2012/05/06/092401996/Budaya-Komplain-Konsumen-Indonesia-Dinilai-Rendah [diakses 2 Maret 2015]. Wijaya, B. S. (2009). Mencermati Balada Prita dan Potret Nestapa Konsumen. Harian Kontan. Edisi 15 Desember 2009. Tersedia: https://bambangsukmawijaya.wordpress.com/2009/12/20/balada-prita-dan-nestapa-konsumen-published-at-kontan-dec-15-2009/ [diakses 2 Maret 2015] Wijaya, B. S. (2009). Brand & Me. ADOI Magazine. Edisi Mei-Juni 2009. Available: https://bambangsukmawijaya.wordpress.com/2009/12/20/brand-inspiration-published-on-adoi-magazine-may-june-2009/ [diakses 2 Maret 2015]. Yayasan Lembaga Konsumen Indonesia (2015). Data Jumlah Pengaduan YLKI

Quasi-geometrical Optics Approximation in Gravitational Lensing

The gravitational lensing of gravitational waves should be treated in the wave optics instead of the geometrical optics when the wave length $\lambda$ of the gravitational waves is larger than the Schwarzschild radius of the lens mass $M$. The wave optics is based on the diffraction integral which represents the amplification of the wave amplitude by lensing. We study the asymptotic expansion of the diffraction integral in the powers of the wave length $\lambda$. The first term, arising from the short wavelength limit $\lambda \to 0$, corresponds to the geometrical optics limit. The second term, being of the order of $\lambda/M$, is the leading correction term arising from the diffraction effect. By analyzing this correction term, we find that (1) the lensing magnification $\mu$ is modified to $\mu ~(1+\delta)$, where $\delta$ is of the order of $(\lambda/M)^2$, and (2) if the lens has cuspy (or singular) density profile at the center $\rho(r) \propto r^{-\alpha}$ ($0 < \alpha \leq 2$), the diffracted image is formed at the lens center with the magnification $\mu \sim (\lambda/M)^{3-\alpha}$.Comment: 9 pages, 4 figures. Revised version accepted for publication in A&

Nonlinear Velocity-Density Coupling: Analysis by Second-Order Perturbation Theory

Cosmological linear perturbation theory predicts that the peculiar velocity $V(x)$ and the matter overdensity $\delta(x)$ at a same point $x$ are statistically independent quantities, as log as the initial density fluctuations are random Gaussian distributed. However nonlinear gravitational effects might change the situation. Using framework of second-order perturbation theory and the Edgeworth expansion method, we study local density dependence of bulk velocity dispersion that is coarse-grained at a weakly nonlinear scale. For a typical CDM model, the first nonlinear correction of this constrained bulk velocity dispersion amounts to $\sim 0.3\delta$ (Gaussian smoothing) at a weakly nonlinear scale with a very weak dependence on cosmological parameters. We also compare our analytical prediction with published numerical results given at nonlinear regimes.Comment: 16 pages including 2 figures, ApJ 537 in press (July 1

LISA Measurement of Gravitational Wave Background Anisotropy: Hexadecapole Moment via a Correlation Analysis

We discuss spatial fluctuations in the gravitational wave background arising from unresolved Galactic binary sources, such as close white dwarf binaries, due to the fact the galactic binary source distribution is anisotropic. We introduce a correlation analysis of the two data streams of the Laser Interferometer Space Antenna (LISA) to extract spherical harmonic coefficients, in an independent manner, of the hexadecapole moment ($l=4$) related to the projected two-dimensional density distribution of the binary source population. The proposed technique complements and improves over previous suggestions in the literature to measure the gravitational wave background anisotropy based on the time modulation of data as LISA orbits around the Sun. Such techniques, however, are restricted only to certain combinations of spherical harmonic coefficients of the galaxy with no ability to separate them individually. With LISA, $m=2,3$ and 4 coefficients of the hexadecapole ($l=4$) can be measured with signal-to-noise ratios at the level of 10 and above in a certain coordinate system. In addition to the hexadecapole coefficients, when combined with the time modulation analysis, the correlation study can also be used, in principle, to measure quadrupole coefficients of the binary distribution.Comment: 8 pages, 2 figure

Energy Efficient Engine (E3) combustion system component technology performance report

The Energy Efficient Engine (E3) combustor effort was conducted as part of the overall NASA/GE E3 Program. This effort included the selection of an advanced double-annular combustion system design. The primary intent of this effort was to evolve a design that meets the stringent emissions and life goals of the E3, as well as all of the usual performance requirements of combustion systems for modern turbofan engines. Numerous detailed design studies were conducted to define the features of the combustion system design. Development test hardware was fabricated, and an extensive testing effort was undertaken to evaluate the combustion system subcomponents in order to verify and refine the design. Technology derived from this effort was incorporated into the engine combustion hardware design. The advanced engine combustion system was then evaluated in component testing to verify the design intent. What evolved from this effort was an advanced combustion system capable of satisfying all of the combustion system design objectives and requirements of the E3