2,404 Works

Dielectric Recovery of Short A-C Arcs Between Low-Boiling-Point Electrodes

Thomas Everett Browne
The re-ignition characteristics (variation of re-ignition voltage with time after current zero) of short alternating current arcs between plane brass electrodes in air were studied by observing the average re-ignition voltages on the screen of a cathode-ray oscilloscope and controlling the rates of rise of voltage by varying the shunting capacitance and hence the natural period of oscillation of the reactors used to limit the current. The shape of these characteristics and the effects on...

A Horizontal Intensity Magnetic Survey Across the Rosamond Fault

Edmund Borys
This problem was undertaken as an effort to gain an acquaintance with magnetic surveying methods and to test their applicability to the interpretation of geologic structure. The Rosamond fault was suggested by Dr. John P. Buwalda as suitable for investigation. It was selected because it appeared to be a well-defined structure and because the magnetic readings taken across it would be subject to only negligible interference from topographic effects. The horizontal intensity survey across the...

A New Theory for Wings of Small Aspect Ratio

William Bollay
Experiments on wings have shown that a very different kind of flow takes place for very small aspect ratios than for large aspect ratios. The lift curve continues up to about 45° before stalling occurs. During this range it has a concave curvature upward rather than downward as the lifting line or lifting surface theories predict. No theoretical explanation of this effect has yet been given since it was generally supposed to be a stalling...

Wind Tunnel Tests on the Effect of Power on the Stability of a Low Wing Monoplane with Three Vertical Positions of Horizontal Tail Surfaces

Calvin Mathews Bolster
A great majority of present day airplanes are of the low wing cantilever type. An investigation into the effect of power and vertical location of the horizontal tail surfaces on the longitudinal static stability of such airplanes is therefore of interest. The present investigation was carried out on a one-sixth scale model of a low wing single engine tractor monoplane. The results are probably most directly applicable to airplanes of this type. However, the tendencies...

Long-Baseline Laser Interferometry for the Detection of Binary Black-Hole Mergers

Evan Drew Hall
Late in 2015, gravitational physics reached a watershed moment with the first direct detections of gravitational waves. Two events, each from the coalescence of a binary black hole system, were detected by the Laser Interferometer Gravitational-wave Observatory (LIGO). At present, LIGO comprises two 4 km laser interferometers, one in Washington and the other in Louisiana; a third detector is planned to be installed in India. These interferometers, known as Advanced LIGO, belong to the so-called...

Contact Behavior and Gas Phenomena in a Vacuum Switch

Frederick Charles Lindvall
Initially a conditioned vacuum switch opens a circuit with a small, momentary arc. This arcing releases gas from the electrodes so that with continued operation a definite rise in gas pressure within the switch was observed. The rate at which gas is evolved was seen to depend both on the value of the interrupted current and on the circuit voltage, increasing either for increasing current or for increasing voltage. Further, definite evidence of getter-action or...

Decoding the Regulatory Genome: Quantitative Analysis of Transcriptional Regulation in Escherichia coli

Stephanie Loos Barnes
Over the past decades DNA sequencing has become significantly cheaper and faster, which has enabled the accumulation of a huge amount of genomic data. However, much of this genomic data is illegible to us. For noncoding regions of the genome in particular, it is difficult to determine what role is played by specific DNA sequences. Here we focus on regions of DNA that play a role in transcriptional regulation. We develop models and techniques that...

Condenser Motor with High Starting Torque and Low Capacitance

Vaino Alexander Hoover & Louis Henry Mesenkop
The theory of the condenser motor is the operation of a poly-phase motor on a single-phase source. If we consider the current in one phase of a two-phase motor the IR drop is in phase with the current I and the reactance drop is at right angles to it. The voltage OB across the phase is the vector sum of these two. Now if a condenser is connected in series with this phase the reactance...

A Comparison of the Costs of Operation of the Motor Bus, Birney Safety Car, and Trolley Bus on the Local Transportation Routes in Pasadena

Douglas Albert Stromsoe
With the installation by the Pacific Electric Railway of a bus system in Pasadena to supplant most of its trolley lines, the problem of the comparison of the costs of the two systems naturally presented itself. The study here undertaken was originally started as just a comparison of the motor bus and Birney Safety Car, but as the work progressed it seemed advisable to include the trolley bus as well - a method of transportation...

Development of Microfluidic Devices with the Use of Nanotechnology to Aid in the Analysis of Biological Systems Including Membrane Protein Separation, Single Cell Analysis, and Genetic Markers

Mark David Goldberg
Computation technology has dramatically changed the world around us; you can hardly find an area where cell phones have not saturated the market, yet there is a significant lack of breakthroughs in the development to integrate the computer with biological environments. This is largely the result of the incompatibility of the materials used in both environments; biological environments and experiments tend to need aqueous environments. To help aid in these development chemists, engineers, physicists and...

Stereoselective Olefin Metathesis Processes Using Cyclometalated Ruthenium Alkylidene Complexes

Lauren Estelle Rosebrugh
The recent development of a class of Z-selective ruthenium metathesis catalysts containing a crucial cyclometalated N-heterocyclic carbene (NHC) ligand has extended the applicability of ruthenium-mediated olefin metathesis to the production of a variety of useful Z-olefin-containing small molecules, polymers, and natural products. This thesis explores the synthesis and application of a number of novel Z-selective cyclometalated ruthenium alkylidene complexes displaying enhanced activity and selectivity across a range of metathesis transformations. Mechanistic investigations aimed at understanding...

Scanning Electrical Mobility Methods for Aerosol Characterization

Huajun Mai
The scanning electrical mobility measurement is the most common tool used to characterize the size distribution of fine particles in the atmosphere. This thesis develops the methods for retrieving the particle size distribution from scanning electrical mobility measurement data for two systems: (1) the scanning electrical mobility spectrometer (SEMS; also known as the scanning mobility particle sizer, SMPS), which measures particle size distribution ranging from 15 - 1000 nm; (2) the scanning radial opposed migration...

New Capabilities of the Notch Signaling Pathway

Nagarajan Nandagopal
Animal cells use a conserved repertoire of signaling pathways to exchange information during and after development. The constituent molecules of these pathways and their individual interactions are now well-characterized. However, it is becoming clear that pathways often possess unexpected signal-processing capabilities, which are typically collective, systems-level, features. Recent work shows that these capabilities are best investigated using quantitative, single-cell, dynamic analyses of pathway behavior. Here, we used this approach to study Notch signaling pathway, which...

The Coherence Collapse Regime of High-Coherence Si/III-V Lasers and the Use of Swept Frequency Semiconductor Lasers for Full Field 3D Imaging

Mark Harfouche
The semiconductor laser is the linchpin of optical communication and is now also penetrating a wide spectrum of new applications such as biomedical sensing, coherent communication, metrology, and time keeping. These require a higher degree of temporal coherence than is available from the present generation. Recently, it has been proposed and shown that heterogeneously integrated lasers on silicon and InGaAsP can be used to design high coherence single mode lasers with a much narrower linewidth...

Online Learning for the Control of Human Standing via Spinal Cord Stimulation

Yanan Sui
Many applications in recommender systems or experimental design need to make decisions online. Each decision leads to a stochastic reward with initially unknown distribution, while new decisions are made based on the observations of previous rewards. To maximize the total reward, one needs to balance between exploring different strategies and exploiting currently optimal strategies within a given set of strategies. This is the underlying trade-off of a number of clinical neural engineering problems, including brain-computer...

Dynamic Earthquake Source Modeling and the Study of Slab Effects

Kangchen Bai
In this Thesis, I report my Ph.D. research on two major issues that are devoted towards constructing more realistic earthquake source model using computational tools: (1) constructing physically consistent dynamic rupture models that include complexities in fault geometry as well as heterogeneous stress and frictional properties inferred from observations; (2) study the effect of subducting slab structure on earthquakes that occur inside it with a special focus on the teleseismic waveforms. Fault step over is...

Imaging the Earth with Ambient Noise and Earthquakes

Yiran Ma
In this thesis, I develop the velocity and structure models for the Los Angeles Basin and Southern Peru. The ultimate goal is to better understand the geological processes involved in the basin and subduction zone dynamics. The results are obtained from seismic interferometry using ambient noise and receiver functions using earthquake- generated waves. Some unusual signals specific to the local structures are also studied. The main findings are summarized as follows: (1) Los Angeles Basin...

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