1,712 research outputs found
Race, Marriage, Markets, Choice, and Some Reflections on is Marriage for White People?
Ni thin films of 1800 Ć
thick were deposited by ion-plating and designed by photolithography to be used as temperature sensors. The resistive paths were finished with contact Cu welding terminals. After being coated with a protective layer of SiOx, they were subjected to heat stabilization treatments. Small, stable and accurate sensors were obtained.Se depositaron trayectos de pelĆcula delgada de Ni de 1800 Ć de espesor diseƱados por fotolitografĆa para ser usados como sensores de temperatura. Los trayectos resistivos fueron provistos de contactos de Cu para soldar terminales. DespuĆ©s de ser recubiertos con una capa de OSi como protecciĆ³n, fueron sometidos a un tratamiento tĆ©rmico de estabilizaciĆ³n. Se obtuvieron sensores pequeƱos, estables y precisos
Turbulent Shear Flow in a Rapidly Rotating Spherical Annulus
This dissertation presents experimental measurements of torque, wall shear stress, pressure, and velocity in the
boundary-driven turbulent flow of water between concentric, independently rotating spheres, commonly known as spherical Couette flow. The spheres' radius ratio is 0.35, geometrically similar to that of Earth's core. The measurements are performed at unprecedented Reynolds number for this geometry, as high as fifty-six million. The role of rapid overall rotation on the turbulence is investigated. A number of different turbulent flow states are possible, selected by the Rossby number, a dimensionless measure of the differential rotation. In certain ranges of the Rossby number near state borders, bistable co-existence of states is possible. In these ranges the flow undergoes intermittent transitions between neighboring states. At fixed Rossby number, the flow properties vary with Reynolds number in a way similar to that of other turbulent flows. At most parameters investigated, the large scales of the turbulent flow are characterized by system-wide spatial and temporal correlations that co-exist with intense broadband velocity fluctuations. Some of these wave-like motions are identifiable as inertial modes. All waves are consistent with slowly drifting large scale patterns of vorticity, which include Rossby waves and inertial modes as a subset. The observed waves are generally very energetic, and imply significant inhomogeneity in the turbulent flow.
Increasing rapidity of rotation as the Ekman number is lowered intensifies those waves identified as inertial modes with respect to other velocity fluctuations. The turbulent scaling of the torque on inner sphere is a focus of this dissertation. The Rossby-number dependence of the torque is complicated. We normalize the torque at a given Reynolds number in the rotating states by that when the outer sphere is stationary. We find that this normalized quantity can be considered a Rossby-dependent friction factor that expresses the effect of the self-organized flow geometry on the turbulent drag. We predict that this Rossby-dependence will change considerably in different physical geometries, but should be an important quantity in expressing the parameter dependence of other rapidly rotating shear flows
The Decline of Marginal Districts in Congressional Elections
Recent research suggests that competition in Congressional elections has been on the decline for more than 50 years, based on incumbent reelection rates and the percentage of close races. Recent elections show the least competitive outcomes dating back to the Post-War era. Currently, there is a multitude of proposed explanations attempting to figure out why there has been such a significant decline in marginal districts. This includes the advantages incumbents have in the reelection process, the effects of redistricting/gerrymandering, the impact of recent partisan polarization, and the significance of campaign finance. In my research I will look at precinct and congressional level data provided by the Secretary of State in 2010 and 2014 statewide elections in California districts, to discover the effects that partisan versus non-partisan gerrymandering has, the level of competition between open and incumbent seats, and the impact that partisan polarization has had in recent elections. I will investigate these results along with looking at former research to determine what has caused the intense increases in āsafeā districts in congressional elections
Dynamic UNITY
Dynamic distributed systems, where a changing set of communicating processes must interoperate to accomplish particular computational tasks, are becoming extremely important. Designing and implementing these systems, and verifying the correctness of the designs and implementations, are difficult tasks. The goal of this thesis is to make these tasks easier.
This thesis presents a specification language for dynamic distributed systems, based on Chandy and Misra's UNITY language. It extends the UNITY language to enable process creation, process deletion, and dynamic communication patterns.
The thesis defines an execution model for systems specified in this language, which leads to a proof logic similar to that of UNITY. While extending UNITY logic to correctly handle systems with dynamic behavior, this logic retains the familiar UNITY operators and most of the proof rules associated with them.
The thesis presents specifications for three example dynamic distributed systems to demonstrate the use of the specification language, and full correctness proofs for two of these systems and a partial correctness proof for the third to demonstrate the use of the proof logic.
The thesis details a method for determining whether a system in the specification language can be transformed into an implementation in a standard programming language, as well as a method for performing this transformation on those specifications that can. This guarantees a correct implementation for any specification that can be so transformed
On the excitation of inertial modes in an experimental spherical Couette flow
Spherical Couette flow (flow between concentric rotating spheres) is one of
flows under consideration for the laboratory magnetic dynamos. Recent
experiments have shown that such flows may excite Coriolis restored inertial
modes. The present work aims to better understand the properties of the
observed modes and the nature of their excitation. Using numerical solutions
describing forced inertial modes of a uniformly rotating fluid inside a
spherical shell, we first identify the observed oscillations of the Couette
flow with non-axisymmetric, retrograde, equatorially anti-symmetric inertial
modes, confirming first attempts using a full sphere model. Although the model
has no differential rotation, identification is possible because a large
fraction of the fluid in a spherical Couette flow rotates rigidly. From the
observed sequence of the excited modes appearing when the inner sphere is
slowed down by step, we identify a critical Rossby number associated with a
given mode and below which it is excited. The matching between this critical
number and the one derived from the phase velocity of the numerically computed
modes shows that these modes are excited by an instability likely driven by the
critical layer that develops in the shear layer staying along the tangent
cylinder of the inner sphere.Comment: 11 pages, 17 figure
Finding Publicly Available Data for Extension Planning and Programming: Developing Community Portraits
Although there have been calls for many years for Extension professionals to use secondary data in their work, finding appropriate data online can still be a challenge. With the multitude of data sources available online, it can be helpful to use the concept of developing a community portrait as the context for becoming proficient at locating secondary data. Once compiled, the data in a community portrait can have multiple uses. In this article, we provide direction for finding specific online data sources and using those sources to compile a community portrait, tips on using data websites, and a quick guide to help with locating data
Transactional Process of African American Adolescentsā Family Conflict and Violent Behavior
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109569/1/jora12056.pd
Snapshot Processing in Streaming Environments
Computational issues related to streaming data, and in particular the monitoring and rapid correlation of multiple sources of streaming data, are becoming increasingly important in contexts ranging from business processes to crisis detection. For example, a government system to detect bioterror attacks must correlate multiple streams of possibly low-confidence data from sensors and local and national public health information networks with cues from indicators such as news and government sources indicating geographical locations, tactics and timing of possible attacks. The results of this correlation trigger appropriate responses, such as flagging information for more in-depth analysis or sending alerts to public health officials. Monitoring and correlation applications of this type are ideal for deployment on distributed computing grids, because they have high transaction throughput, require low latency, and can be partitioned into sets of small communicating computations with regular communication patterns. An important consideration in these applications is the need to ensure that, at any given time, computations are carried out on an accurate - or at least close to accurate - picture of the environment being monitored. One way of doing this, which we call snapshot processing, is to treat collections of events that occur at approximately the same time as representing a global snapshot - a valid state - of the environment. Computation on the resulting series of snapshots is much like computation on a real-time video of the entire environment. We briefly describe our model for these stream processing computations and introduce the concept of snapshot processin
Porcine reproductive and respiratory syndrome monitoring in breeding herds using processing fluids
Processing fluids (PF), the serosanguinous fluid recovered from piglet castration and tail docking, were used for porcine reproductive and respiratory syndrome virus (PRRSV) infection assessment. Processing fluid samples from four breed-to-wean herds were compared with standard sampling protocols, demonstrating PRRSV RNA detection in PF at greater frequency than standard schemes
A parallel algorithm for correlating event streams
This paper describes a parallel algorithm for correlating or āfusingā streams of data from sensors and other sources of information. The algorithm is useful for applications where composite conditions over multiple data streams must be detected rapidly, such as intrusion detection or crisis management. The implementation of this algorithm on a multithreaded system and the performance of this implementation are also briefly described
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