Analytical aerodynamic model of a high alpha research vehicle wind-tunnel model

A 6 DOF analytical aerodynamic model of a high alpha research vehicle is derived. The derivation is based on wind-tunnel model data valid in the altitude-Mach flight envelope centered at 15,000 ft altitude and 0.6 Mach number with Mach range between 0.3 and 0.9. The analytical models of the aerodynamics coefficients are nonlinear functions of alpha with all control variable and other states fixed. Interpolation is required between the parameterized nonlinear functions. The lift and pitching moment coefficients have unsteady flow parts due to the time range of change of angle-of-attack (alpha dot). The analytical models are plotted and compared with their corresponding wind-tunnel data. Piloted simulated maneuvers of the wind-tunnel model are used to evaluate the analytical model. The maneuvers considered are pitch-ups, 360 degree loaded and unloaded rolls, turn reversals, split S's, and level turns. The evaluation finds that (1) the analytical model is a good representation at Mach 0.6, (2) the longitudinal part is good for the Mach range 0.3 to 0.9, and (3) the lateral part is good for Mach numbers between 0.6 and 0.9. The computer simulations show that the storage requirement of the analytical model is about one tenth that of the wind-tunnel model and it runs twice as fast

Source plane reconstruction of the giant gravitational arc in Abell 2667: a candidate Wolf-Rayet galaxy at z~1

We present a new analysis of HST, Spitzer telescope imaging and VLT imaging and spectroscopic data of a bright lensed galaxy at $z$=1.0334 in the lensing cluster Abell~2667. Using this high-resolution imaging we present an updated lens model that allows us to fully understand the lensing geometry and reconstruct the lensed galaxy in the source plane. This giant arc gives a unique opportunity to peer into the structure of a high-redshift disk galaxy. We find that the lensed galaxy of Abell 2667 is a typical spiral galaxy with morphology similar to the structure of its counterparts at higher redshift $z\sim 2$. The surface brightness of the reconstructed source galaxy in the z$_{850}$ band reveals the central surface brightness $I(0)=20.28\pm0.22$ mag arcsec$^{-2}$ and the characteristic radius $r_s=2.01\pm0.16$ kpc at redshift $z \sim 1$. The morphological reconstruction in different bands shows obvious negative radial color gradients for this galaxy. Moreover, the redder central bulge tends to contain a metal-rich stellar population, rather than being heavily reddened by dust due to high and patchy obscuration. We analyze the VIMOS/IFU spectroscopic data and find that, in the given wavelength range ($\sim 1800-3200$ \AA), the combined arc spectrum of the source galaxy is characterized by a strong continuum emission with strong UV absorption lines (FeII and MgII) and shows the features of a typical starburst Wolf-Rayet galaxy NGC5253. More specifically, we have measured the EWs of FeII and MgII lines in the Abell 2667 spectrum, and obtained similar values for the same wavelength interval of the NGC5253 spectrum. Marginal evidence for CIII] 1909 emission at the edge of the grism range further confirms our expectation.Comment: 20 pages, 7 figures, 1 table, accepted by the Astronomical Journa

Negative Differential Conductance and Hot Phonons in Suspended Nanotube Molecular Wires

Freely suspended metallic single-wall carbon nanotubes (SWNTs) exhibit reduced current carrying ability compared to those lying on substrates, and striking negative differential conductance (NDC) at low electric fields. Theoretical analysis reveals significant self-heating effects including electron scattering by hot non-equilibrium optical phonons. Electron transport characteristics under strong self-heating are exploited for the first time to probe the thermal conductivity of individual SWNTs (~ 3600 Wm-1K-1 at T=300 K) up to ~700 K, and reveal a 1/T dependence expected for Umklapp phonon scattering at high temperatures.Comment: PRL, in pres

New Terephthalic Acid Process

Terepthalic acid is primarily utilized as a raw material to make polyester PET, a polymer used to make a variety of household items such as clothing and plastic bottles. Currently, the most common method used to produce TPA is a technology called the Amoco Process, in which paraxylene is oxidized in the presence of a corrosive catalyst promoter. The corrosive promoter necessitates expensive equipment that is clad with titanium or other expensive alloys. Recently, a new non-corrosive ionic liquid promoter was discovered that would allow for stainless steel equipment. In this report, a process was designed to produce terephthalic acid using the new ionic liquid technology. The process was analyzed for technological and economic feasibility, while also considering other potential issues such as safety and start-up. The designed plant produces 800 million pounds of crude terephthalic acid (TPA) a year in the Gulf Coast. Under the assumed economic conditions, this process is projected to have a net present value of $110,840,600 in the year 2011 with an attractive internal rate of return of 34.07%, making this project more profitable than the Amoco Process due to the significantly decreased total capital investment required by this new technology