On non-convergence of adjoint semigroups for control systems with delays

It is shown that the adjoints of a spline based approximation scheme for delay equations do not converge strongly

Theoretical and experimental studies of the underlying processes and techniques of low pressure measurement Semiannual status report, Sep. 1, 1964 - Feb. 28, 1965

Pumping of getter-ion pumps at low pressure, crossed field mass spectrometer, secondary electron emission, angular distribution of Auger electrons, and gaseous adsorptio

Exchanges between residents and tourism development

This qualitative study focused on utilizing a combination of social exchange and power theories to wxplain exchange that occurt between residents of Langkawi and tourism development on the island. The guiding question for this inquiry was "what role does power play in social exchanges that occur between residents and tourism development?" Findings revealed that social exchanges is useful in examining residents' attitudes towards tourism as residents indeed based their attitudes on the evaluation of the returns that they receive from the exchanges. More importantly, the findings indicated that residents' general values, their dependence on tourism, and their ability and willingness to adapt moderated the influence of power on residents' evaluation of tourism impacts

A comparison of time domain boundary conditions for acoustic waves in wave guides

Researchers consider several types of boundary conditions in the context of time domain models for acoustic waves. Experiments with four different duct terminations (hard wall, free radiation, foam, and wedge) were carried out in a wave duct from which reflection coefficients over a wide frequency range were measured. These reflection coefficients were used to estimate parameters in the time domain boundary conditions. A comparison of the relative merits of the models in describing the data is presented. Boundary conditions which yield a good fit of the model to the experimental data were found for all duct terminations except the wedge

Theoretical and experimental studies of the underlying processes and techniques of low pressure measurement Progress report, 1 Jun. 1966 - 31 May 1967

Construction, testing, and refining of vacuum gauges - ionization gauge cross section ratio

NVV auger spectra from W(100)

The NVV Auger spectrum from a clean W(100) surface has been measured in the second derivative, d^2N (E)/dE^2, mode to enhance fine structure. This measurement is compared with spectra generated from both the self‐convolution of the tungsten valence‐band bulk density of states (obtained from a relativistic APW energy band calculation) and a "restricted convolution" in which only transitions involving electrons from the same valence energy are allowed. The restricted convolution for a model of the Auger process in which both N_6VV and N_7VV transitions contribute offers the best match of theory and experiment. No distinct evidence of Auger emission involving the surface resonance present on W(100) is observed. Effects of H_2 and O_2 adsorption on the Auger spectrum of the W(100) surface are reported

Operational Use of GPS Navigation for Space Shuttle Entry

The STS-118 flight of the Space Shuttle Endeavour was the first shuttle mission flown with three Global Positioning System (GPS) receivers in place of the three legacy Tactical Air Navigation (TACAN) units. This marked the conclusion of a 15 year effort involving procurement, missionization, integration, and flight testing of a GPS receiver and a parallel effort to formulate and implement shuttle computer software changes to support GPS. The use of GPS data from a single receiver in parallel with TACAN during entry was successfully demonstrated by the orbiters Discovery and Atlantis during four shuttle missions in 2006 and 2007. This provided the confidence needed before flying the first all GPS, no TACAN flight with Endeavour. A significant number of lessons were learned concerning the integration of a software intensive navigation unit into a legacy avionics system. These lessons have been taken into consideration during vehicle design by other flight programs, including the vehicle that will replace the Space Shuttle, Orion

Theoretical and experimental studies of the underlying processes and techniques of low pressure measurement Letter report, 1 Jul. 1967 - 31 May 1968

Ionization gage behavior in various gas mixtures and atmospheric composition

Nondestructive SEM for surface and subsurface wafer imaging

The scanning electron microscope (SEM) is considered as a tool for both failure analysis as well as device characterization. A survey is made of various operational SEM modes and their applicability to image processing methods on semiconductor devices

Abstract wave equations with acoustic boundary conditions

We define an abstract setting to treat wave equations equipped with time-dependent acoustic boundary conditions on bounded domains of ${\bf R}^n$. We prove a well-posedness result and develop a spectral theory which also allows to prove a conjecture proposed in (Gal-Goldstein-Goldstein, J. Evol. Equations 3 (2004), 623-636). Concrete problems are also discussed.Comment: 21 pages. A few minor bugs appearing in the journal version have been fixe