Engineering topics
Jordan, T.
Publications and source records attributed to Jordan, T..
Total Dose Survivability of Hubble Electronic Components
A total dose analysis for exposure of electronic parts at the box level is presented for the Hubble Space Telescope. This was done using solid angle sectoring/3-dimensional ray trace and Monte Carlo radiation transport simulations. Results are discussed in terms of parts that are potential total dose concerns.
How Long Can the Hubble Space Telescope Operate Reliably?
Total ionizing dose exposure of electronic parts in the Hubble Space Telescope is analyzed using 3-D ray trace and Monte Carlo simulations. Results are discussed along with other potential failure mechanisms for science operations.
NIEL for Heavy Ions: An Analytical Approach
We describe an analytical model for calculating NIEL for heavy ions based upon screened Coulomb potentials. The model applies to any incident ion on any target material in the Coulombic limit.
Nonionizing energy loss (NIEL) for protons
The proton induced NIELs for representative spacecraft materials are presented for the energy range between the displacement thresholds of the material to 1000 MeV. All interaction mechanisms (Coulomb and nuclear elastic/inelastic) are fully accounted in the present NIEL calculations.
Proton nonionizing energy loss (NIEL) for device applications
The proton induced NIEL for representative device materials are presented for the energy range between 1 keV to 1000 MeV.
Electrical Properties and Power Considerations of a Piezoelectric Actuator
This paper assesses the electrical characteristics of piezoelectric wafers for use in aeronautical applications such as active noise control in aircraft. Determination of capacitive behavior and power consumption is necessary to optimize the system configuration and to design efficient driving electronics. Empirical relations are developed from experimental data to predict the capacitance and loss tangent of a PZT5A ceramic as nonlinear functions of both applied peak voltage and driving frequency. Power consumed by the PZT is the rate of energy required to excite the piezoelectric system along with power dissipated due to dielectric loss and mechanical and structural damping. Overall power consumption is thus quantified as a function of peak applied voltage and driving frequency. It was demonstrated that by incorporating the variation of capacitance and power loss with voltage and frequency, satisfactory estimates of power requirements can be obtained. These relations allow general guidelines in selection and application of piezoelectric actuators and driving electronics for active control applications.
Composition and evolution of the mantle and core
Earth interior structure, composition and evolution, using seismic, ultrasonic, shock wave and petrological data
Application of isotropic finite strain theory to ultrasonic and seismological data
Isotropic finite strain expressions for compressional and shear velocities, noting no discrepency with ultrasonic and seismic data