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A magnetic tunnel junction is a device that changes its electrical resistance with a change in an applied magnetic field. A typical junction consists of two magnetic electrodes separated by a nonmagnetic insulating layer. The magnetizations of the two electrodes can have two possible extreme configurations, parallel and antiparallel. The antiparallel configuration is observed to have the higher measured resistance and the parallel configuration has the lower resistance. To switch between these two configurations a magnetic field is applied to the device which is primarily used to change the orientation of the magnetization of one electrode usually called the free layer, although with sufficient high magnetic field the orientation of the magnetizations of both of the electrodes can be changed. The most commonly used models for describing and explaining the electronic behavior of tunnel junctions are the Simmons model and the Brinkman model. However, both of these models were designed for simple, spin independent tunneling. The Simmons model does not address the issue of applied magnetic fields nor does it address the form of the electronic band structure in the metallic electrodes, including the important factor of spin polarization. The Brinkman model is similar, the main difference between the two …

The work presented in this dissertation has investigated three distinct areas of interest in the field of quasicrystals: bulk structure, transport properties, and electronic structure. First, they have described the results of a study which explored the fundamental interactions between the atomic species of the icosahedral Al-Pd-Mn quasicrystal. The goal of this work was to determine whether the pseudo-MacKay or Bergman type clusters have a special stability or are merely a geometric coincidence. This was carried out by using laser vaporization to produce gas-phase metal clusters, which were analyzed using time-of-flight mass spectrometry. Both the kinetic and thermodynamic stabilities of the clusters were probed. The data indicated no special stability for either pseudo-MacKay or Bergman type clusters as isolated units. This, however, is not proof that these clusters are simply a geometric coincidence. It is possible that such clusters only have stability in the framework of the bulk matrix and do not exist as isolated units. Next, they have reported their investigations of the bulk thermal transport properties of a decagonal Al-Ni-Co two dimensional quasicrystal in the temperature range 373K-873K. The properties of a sample oriented along the periodic axis and another oriented along the aperiodic axis were measured. A …

This report discusses intelligence issues for Congress including terrorism, conflicts between Israel and Palestine, in Iraq, and among the former Yugoslav states, and North Korean missile capabilities. Updated August 5, 2003.

We provide a detailed study of the phenomenology of orbifold compactifications of the heterotic string within the context of supergravity effective theories. Our investigation focuses on those models where the soft Lagrangian is dominated by loop contributions to the various soft supersymmetry breaking parameters. Such models typically predict non-universal soft masses and are thus significantly different from minimal supergravity and other universal models. We consider the pattern of masses that are governed by these soft terms and investigate the implications of certain indirect constraints on supersymmetric models, such as flavor-changing neutral currents, the anomalous magnetic moment of the muon and the density of thermal relic neutralinos. These string-motivated models show novel behavior that interpolates between the phenomenology of unified supergravity models and models dominated by the superconformal anomaly.

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.

The two policy committees are different in structure and operation, a contrast that appears to be rooted in different leadership styles within the two party organizations. Republican leadership has traditionally been shared among Senators other than the party floor leader; customarily, the Democratic leadership positions of party floor leader, chair of the Democratic Policy Committee, and chair of the Democratic Conference have been posts held by the same person. This report covers the history of the two Senate policy committees and explains their structure, operation, and functions.

Semiweekly newspaper from Boerne, Texas that includes local, state, and national news along with advertising.

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.

Scene-Based Wave Front Sensing uses the correlation between successive subimages to determine phase aberrations which blur digital images. Adaptive Optics technology uses deformable mirrors to correct for these phase aberrations and make the images clearer. The correlation between temporal subimages gives tip-tilt information. If these images do not have identical image content, tip-tilt estimations may be incorrect. Motion detection is necessary to help avoid errors initiated by dynamic subimage content. In this document, I will discuss why edge detection fails as a motion detection method on low resolution images and how thresholding the normalized variance of individual pixels is successful for motion detection.

Organic light-emitting devices (OLEDs) constitute a new and exciting emissive display technology. In general, the basic OLED structure consists of a stack of fluorescent organic layers sandwiched between a transparent conducting-anode and metallic cathode. When an appropriate bias is applied to the device, holes are injected from the anode and electrons from the cathode; some of the recombination events between the holes and electrons result in electroluminescence (EL). Until now, most of the efforts in developing OLEDs have focused on display applications, hence on devices within the visible range. However some organic devices have been developed for ultraviolet or infrared emission. Various aspects of the device physics of doped small molecular OLEDs were described and discussed. The doping layer thickness and concentration were varied systematically to study their effects on device performances, energy transfer, and turn-off dynamics. Low-energy-gap DCM2 guest molecules, in either {alpha}-NPD or DPVBi host layers, are optically efficient fluorophores but also generate deep carrier trap-sites. Since their traps reduce the carrier mobility, the current density decreases with increased doping concentration. At the same time, due to efficient energy transfer, the quantum efficiency of the devices is improved by light doping or thin doping thickness, in comparison with …

The study of fast ion instabilities in conventional aspect ratio tokamaks is motivated in large part by their potential to negatively impact the ignition threshold in fusion reactors by causing fast ion losses. Spherical tokamak's (ST), with intrinsically low magnetic fields, are particularly susceptible to fast ion driven instabilities. The 3.5 MeV alpha's from the D-T [deuterium-tritium] fusion reaction in proposed ST reactors will have velocities much higher than the Alfven speed. The Larmor radius of the fusion alphas, normalized to the plasma size, will also be larger than for conventional aspect ratio tokamak reactors. The resulting longer wavelengths of the *AE instabilities will be more effective in driving fast ion loss. The change in magnetic topology also influences the mode structure, as in the case of the Compressional Alfven Eigenmodes (CAE) seen on NSTX.

The 2000 and 2002 fire seasons were, by most standards, among the worst in the past 50 years. Many argue that the threat of severe wildfires has grown in recent years because of unnaturally high fuel loads (e.g., dense undergrowth and dead trees), raising concerns about damage to property and homes in the wildland-urban interface (WUI) — forests near or surrounding homes. Debates about fire control and protection, including funding and fuel treatments (e.g., thinning and prescribed burning), have focused on national forests and other federal lands, but nonfederal lands are also at risk.

Semiweekly newspaper from Sealy, Texas that includes local, state, and national news along with advertising.

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During the first session of the 108th Congress, the House and Senate will consider many different budgetary measures. Most measures pertain to fiscal year (FY) 2004 (which began on October 1, 2003) and beyond. Some also pertain to the budget for FY2003. As the session progresses, this report will describe House and Senate action on major budgetary legislation within the framework of the congressional budget process and other procedural requirements.

Weekly newspaper from Emory, Texas that includes local, state, and national news along with advertising.

This report discusses recent attempts at legislative action regarding changes to the computation of benefits under Social Security Amendments of 1977 (P.L. 95-216), which directly affected retirees born in the 5- to 15-year period after 1916. These persons fall in the "notch" between previous Social Security legislation and those affected by the amendments.

The oxidation resistance of a high-temperature alloy is dependent upon sustaining the formation of a protective scale, which is strongly related to the alloying composition and the oxidation condition. The protective oxide scale only provides a finite period of oxidation resistance owing to its eventual breakdown, which is especially accelerated under thermal cycling conditions. This current study focuses on the long-term cyclic oxidation behavior of a number of commercial wrought alloys. The alloys studied were Fe- and Ni-based, containing different levels of minor elements, such as Si, Al, Mn, and Ti. Oxidation testing was conducted at 1000 and 1100 C in still air under both isothermal and thermal cycling conditions (1-day and 7-days). The specific aspects studied were the oxidation behavior of chromia-forming alloys that are used extensively in industry. The current study analyzed the effects of alloying elements, especially the effect of minor element Si, on cyclic oxidation resistance. The behavior of oxide scale growth, scale spallation, subsurface changes, and chromium interdiffusion in the alloy were analyzed in detail. A novel model was developed in the current study to predict the life-time during cyclic oxidation by simulating oxidation kinetics and chromium interdiffusion in the subsurface of chromia-forming alloys.

CFD (Computational Fluid Dynamics) is a widely used technique in engineering design field. It uses mathematical methods to simulate and predict flow characteristics in a certain physical space. Since the numerical result of CFD computation is very hard to understand, VR (virtual reality) and data visualization techniques are introduced into CFD post-processing to improve the understandability and functionality of CFD computation. In many cases CFD datasets are very large (multi-gigabytes), and more and more interactions between user and the datasets are required. For the traditional VR application, the limitation of computing power is a major factor to prevent visualizing large dataset effectively. This thesis presents a new system designing to speed up the traditional VR application by using parallel computing and distributed computing, and the idea of using hand held device to enhance the interaction between a user and VR CFD application as well. Techniques in different research areas including scientific visualization, parallel computing, distributed computing and graphical user interface designing are used in the development of the final system. As the result, the new system can flexibly be built on heterogeneous computing environment, dramatically shorten the computation time.

This data report discusses the methods and philosophy used to characterize two samples of sludge and one sample of drainable liquid from tank 241-AY-102 at the Hanford Site. Archived samples of sludge and drainable liquid from tank 241-AY-102 were characterized in the laboratory in order to evaluate analytical methods for testing tank waste and determine the composition and leaching characteristics of this material. The tests included physical characterization, quantitative analysis of waste composition, and short-term water leach and acid digestion of the waste material. The water leach tests were conducted over time periods of one day, two weeks, and one month to determine if contact time had an impact on leachability. Comparisons of the results of the water leach tests with the acid digestions allow for an estimation of the water leachable percentage of an element. The average water leachability of Tc-99 was measured at 20% over the one-month time frame of the leach tests. There did not appear to be any temporal change in water leachability by comparing the results of the three sampling intervals. Approximately 24 to 48% of the total Cs-137 in the sludge is water leachable over a time period of one day to one month. …

China’s economy remained relatively healthy in 2002, despite economic slowdowns in other parts of the world. Foreign investment continued to pour into China, and the Chinese government effectively used public spending to boost the economy. However, painful economic reforms will be necessary to keep the economic strong in 2003 and beyond. The recent outbreak in early 2003 of a very contagious virus called SevereAcuteRespiratory Syndrome (SARS) in China appears to have had a short-term negative impact on the Chinese economy.