The drift velocity of electrons in pure hydrogen, in pure deuterium, and in mixtures thereof, has been observed at low pressures using the following pulse technique for these gases for the first time. Plane parallel electrodes of a known separation and immersed in the gas to be studied are connected...
A configuration-interaction determination of wave
functions has been made for the ²S and ²P states of lithium,
and for the ¹S and ³S states of the lithium ion.
Two 1s, one 2s, one 3s, and two 2p functions served as
starting functions for all four states. Results of the
total...
The energy distribution of electrons in Townsend discharges in
helium has been experimentally investigated in a direct fashion.
A discharge is initiated between parallel plates of a small cell
mounted at the center of a spherical retarding field energy analyzer.
The anode of the cell is perforated and some electrons...
A knowledge of the time rates for intermediate reactions
during the photolysis of nitrogen dioxide enables one to deduce the
possible intermediate reactions which are responsible. An experiment has been devised and constructed which will measure the time
rates for photochemical reactions occurring in ranges of one micro
second to...
In this work the electron energy distribution functions and the
anisotropic drift term of the velocity distribution functions in non-self-sustaining
(Townsend) discharges in argon were determined by
direct measurement for a range of E/N (electric field strength by
gas atom concentration) from 70 to 407 Townsends (Td). (One Td
equals...
The three-body heterogeneous and wall recombination coefficients for atomic oxygen were measured using an electron paramagnetic
resonance spectrometer to monitor the time dependence of the
atomic oxygen concentration. This measurement was made for a
pressure range of from .224 to 1.10 torr using pyrolysis of ozone as
a source of...
When pavement markings on roadways are removed, scarring can occur leaving behind traces of where the marking used to be called ghost lines. These ghost lines can confuse drivers on the roadway and divert their attention from the correct lane markings leading them into the false lane. Previous research has...
Creating schedules for the job shop manufacturing system is an extremely difficult task. Although researchers have devoted a lot of attention to generating optimal solutions, these solutions are static, thus they do not update as random events occur that disrupt the system. As smart manufacturing has grown, researchers have been...
The Manual on Uniform Traffic Control Devices prohibits positioning a bike lane right-adjacent to a vehicle turn-only lane to mitigate the potential for right-hook crashes. However, it provides no specific guidance on positioning with respect to bus-only lanes. This thesis describes a before/after safety evaluation of bike lanes positioned left...
Previous research has found some bicyclists disregard circular red indications and stop signs. Possible justifications include a desire to increase safety, save energy, save time, and increase visibility. Because of this, many bicyclists feel as though stopping at stop signs, especially in the absence of conflicting vehicular traffic, is an...
As e-commerce and urban deliveries spike, there is an increasing demand for curbside loading/unloading space. However, commercial vehicle drivers face numerous challenges while navigating dense urban road networks. Previous literature on the topic of how commercial vehicle drivers make choices about when and where to park is scarce, and data...
It is considered best practice when designing pedestrian access at intersections to provide two curb ramps at each street corner. In Oregon, there are many locations where long ramp runs cause curb ramps to be set back a significant distance from the apex of the intersection corner to meet this...
In discrete event simulation, probability distributions are used as models of various unpredictable system components. The times between equipment failures and job processing times are examples of such random system components. The commonly recommended and taught practice for selecting a probability distribution to represent a random component is a multistep...
In high volume automated discrete item batch production systems, the batches or lots are typically fixed quantity (i.e., size), with setups incurred between the different production lots. Processing times for the fixed-size lots are relatively constant when the workstation is operating however, random workstation disruptions cause variability in the lot...
Bicyclist safety at urban intersections is a critical element for encouraging an increase in bicycle commuting. With bicycle injury and fatality rates rising due to collisions with vehicles at signalized intersections, increasing the safety of riders continues to be an important consideration when promoting this mode of transportation. Previous research...
The variability introduced into measurements by a measuring instrument is referred to as measurement instrument precision. Experimental procedures and analysis methods exist when measurements are repeatable and can be repeated on the same item. However, when the measurements are destructive and repeated measurements are not possible, estimating measuring instrument precision...
Intersections pose unique transportation challenges regarding safety and operational efficiency. When pedestrians currently want to cross at intersection, they need to use a push button to issue a call for service. The call is static and cannot be altered or changed. But by implementing dynamic passive pedestrian detection sensors, intersections...
Autonomous vehicles (AVs) at varying market penetrations will change traffic flow and highway performance. At AV market penetrations between 0% and 100%, human driven vehicles (HVs) will be interacting with AVs. However, little is known about how HVs interact with AVs. This study attempts to quantify HV headways when following...
Travel demand has increased due to population growth, increase of vehicle ownership, and development patterns resulting in greater levels of congestion, pollution, and crash frequency. One approach to demand management is to increase the share of trips made by bicycles. With the increase in bicycling rates, there is a critical...
Accommodating motor vehicles that are turning (left or right) at signalized intersections requires a careful understanding of the safety and efficiency of design and operational variables. Turning vehicles are the primary collision risk for non-motorized road users at signalized intersections. When turning movements need to be controlled, proper driver response...
Roadway departure crashes accounted for 18,275 fatal crashes in 2017 across the United States (Jones et al. 2017). Rumble strips (RS) provide audible and haptic interior alert when a vehicle is departing the roadway reducing run-off-the road crashes. Although inexpensive to install, and easy to maintain, RS are not installed...
Moving mixed-model assembly lines are used by many companies to assemble multiple model types of a particular product. A moving assembly line consists of a material movement system that moves jobs at a constant velocity across a series of workstations. The variation in the work content of jobs at workstations...
Dilemma zones on the approach to high-speed signalized intersections have been identified as a safety problem that can contribute to rear–end and right–angle crashes. However, in situations when a pair of vehicles is caught in the dilemma zone, it is not well understood how the following vehicle’s headway and classification...
Unmanned aerial systems (UASs), more commonly known as drones, have recently achieved commercial success for many public and private applications. As with all emerging technologies, new safety concerns and conflicts with existing paradigms are likely to arise. Many potential applications of UASs will result in their operation near roadway infrastructure,...
The total manufacturing cost for a part is determined by its process plan, and the total cost includes both processing and material handling costs. This research examines the cost impact of assuming an arbitrary layout when evaluating alternative process plans for production in a new facility. A designed experiment was...
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_____________________________________________________________________
DavidS. Kim, Mentor, representing School of Mechanical, Industrial, and Manufacturing
Left turn movements are considered to be the highest risk movements through an intersection, and can result in head on, angle, or side impact crashes. The flashing yellow arrow (FYA) for use as a permissive left turn phasing indication is relatively recent, first appearing in the 2009 edition Manual on...
While sophisticated plans have been adopted nationally and globally to increase bicycling’s share of daily commutes, safety concerns have negatively impacted targeted bicycling growth. Specifically, truck traffic plays a pivotal role in bicyclists’ perceptions of safety and comfort, because of the severe consequences of bicycle-truck collisions. Several types of engineering...
Autonomous vehicles (AVs) may have the potential to mitigate a significant proportion of serious crashes which are due to human error or poor decision making behind the wheel. However, there are still many concerns associated with SAE Level 3 AVs that require intervention by a human driver after a take-over...
Red Signal Countdown Timers (RSCTs) are devices placed at intersections to inform drivers of the time remaining on a red indication before it turns green, typically to improve intersection efficiency. This study examines the visual attention of Oregon drivers to circular red (CR) indications with RSCTs as compared to standard...
Red Light Running (RLR) is a safety hazard at signalized intersections in Oregon and throughout the United States. Various methods of mitigating factors contributing to RLR have been implemented but few protect against a conflict when a vehicles runs a red light. Additionally, current prediction algorithms are complicated; there is...
A right-hook crash is a bicycle-motor vehicle crash between a right-turning motor vehicle and an adjacent through-moving bicycle. This study focuses on right-hook crashes that occur during the latter stage of the circular green indication at signalized intersections with shared right-turn and through lanes. The overall objective was to evaluate...
The use of in-vehicle technologies, such as mobile phones, while driving has proliferated in recent years. Most notably, drivers are using mobile phones to send and receive text messages while operating a vehicle with increasing frequency. The act of texting while driving poses a significant threat not only to the...
A Right-hook (RH) crash is a common type of bicycle-motor vehicle crash that occurs between a right-turning vehicle and through-moving bicycle at an intersection. At signalized intersections, RH crashes can occur at the onset of the green or during the latter portion of the green phase. In spite of the...
Traffic signal countdown timers (TSCT) are innovative, practical and cost effective technologies with the potential to improve efficiency and safety at signalized intersections. The purpose of these devices is to assist motorists in decision making at signalized intersections with real time signal change information. While successful implementation of these devices...
The number of international inbound tourists to the United States has risen steadily. To serve these and other tourists best, traffic signs need to communicate information correctly across a potential language barrier. Of particular interest is the traffic sign intended to communicate directions to Tourist Information centers. While the general...
The author studies the class of rectangular arrangements in
terms of two binary relations on the objects of the arrangement.
He shows how a univalent matrix determines a unique rectangular
arrangement, and how each rectangular arrangement is associated
with one, two, or four distinct matrices, according to the number
of...
This report presents a characterization of the quantum mechanical
analog of the Gibbs canonical density. The approach is
based on a method developed by D.S. Carter for the case of classical
statistical mechanics, which considers composite mechanical systems
composed of mechanically and statistically independent components.
After a brief introductory chapter,...
This research effort considers bicyclist’s left-turn behavior at roadway intersections with varying levels of traffic control; specifically, seeking to address the question where do bicyclists look to acquire information. A demographic comparison was made to determine if factors such as gender or experience influence the nature of how a bicyclist...
Monte Carlo simulation is used to quantify and characterize uncertainty in a variety of applications such as financial/engineering economic analysis, and project management. The dependence or correlation between the random variables modeled can also be simulated to add more accuracy to simulations. However, there exists a difference between how correlation...
Small-mammal community composition, microhabitat selection, and
dispersal of mycorrhizal fungal spores were studied in southwestern
Oregon. Sampled habitats exhibited structural variation resulting
from silvicultural practices.
In 1981, the effect of clearcut treatment on these phenomena was
evaluated. In 1982, the effect of forest structure was studied.
Discriminant function analysis (DFA)...
In the problem of testing the median using a random sample from a
certain distribution, and if no other parametric family is suggested,
the t-test is known to be the optimal procedure when this distribution
is normal. If the sample appears to be non-normal, one has the choice
either to...
This dissertation considers two approaches for testing hypotheses in
unbalanced mixed linear models. The first approach is to construct a design with
some type of structure or "partial" balance, so that some of the optimal properties of
a completely balanced design hold. It is shown that for a particular type...
Mixed models have been widely used to model data from experiments which have fixed and random
factors. Often there is interest in the estimation of fixed effects and variance components. The likelihood
procedure is a general technique that has been applied to such problems. This procedure can be
computationally difficult,...
In this research, an analytical model for analyzing a production line consisting of a series
of automated workstations with infinite buffers is developed. Automated workstations are
assumed to have deterministic processing times, and independent exponentially
distributed operating time between failures and repair times. The analytical model starts
with existing results...
The research presented in this dissertation addresses the Multi-Mode Resource-Constrained Project Scheduling Problem (MMRCPSP) in the presence of resource unavailability. This research is motivated by the scheduling of engineering design tasks in automotive product development to minimize the project completion time, but addresses a general scheduling situation that is applicable...
The Type-II dilemma zone refers to the segment of roadway approaching an
intersection where drivers have difficulty deciding to stop or proceed through at
the onset of the circular yellow (CY) indication. Signalized intersection safety can
be improved when the dilemma zone is correctly identified and steps are taken to...