Digital Commons Network^™

Effects Of Pyrolysis Heating Rate On Intrinsic Reactivities Of Coal Chars, Thomas K. Gale, Calvin H. Bartholomew, Thomas H. Fletcher

Faculty Publications

The main objective of this work was to determine the effects of pyrolysis heating rate on intrinsic O₂ reactivity of coal chars. Relationships of intrinsic reactivity to other pyrolysis conditions and char physical and chemical structure were also investigated, and empirical correlations were obtained. Two different entrained flow reactors (a flat flame methane/air burner and a drop tube reactor) were used to prepare chars under a variety of different pyrolysis conditions at maximum particle temperatures and heating rates of 840-1627 K and 10⁴ to 2x10⁵ K/s, respectively. Intrinsic reactivities of a lignite and two bituminous coal chars …

Journey: Connections To A Pioneer Past, Judy Shell Busk

Theses and Dissertations

This thesis is a record of a journey into the pioneer past both literally and metaphorically. The physical journey retracing the Oregon and Mormon trails was made in September of 1993, the year I was a National Endowment for the Humanities/Reader's Digest Teacher-Scholar; however, my intellectual and emotional journey into the lives of pioneer women covers several years of study. I compare my life experiences with those of pioneer women whom I studied, using geographical settings on the trail trip as memory triggers. My husband, as my traveling companion, plays an important role in this journey of discovery. Major themes …

Let's Surf-The-Net! World-Wide Web (Www) Sites In Italy, Or: How/Why Include A Web-Browser Component In Culture And Civilization Classes, Ilona Klein

Faculty Publications

First, this essay details the technical elements required to set up a computer for Web-surfing, then it discusses the rationale for a Web-browser component in Culture and Civilization courses. The first part of this study (the technical portion) is geared specifically toward teachers with little or no familiarity with the Internet and the World-Wide Web. In the second part of the article, the applied-pedagogy aspects of Web-browsing are provided for all colleagues in the profession, proficient or not in cyberspace surfing. This article argues that the internet and the World-Wide Web are here to stay and that, within certain limitations, …

Combustion Modeling Of Rdx, Hmx And Gap With Detailed Kinetics, Jeffrey E. Davidson

Theses and Dissertations

A one-dimensional, steady-state numerical model of the combustion of homogeneous solid propellant has been developed. The combustion processes is modeled in three regions: solid, two-phase (liquid and gas) and gas. Conservation of energy and mass equations are solved in the two-phase and gas regions and the eigenvalue of the system (the mass burning rate) is converged by matching the heat flux at the interface of these two regions. The chemical reactions of the system are modeled using a global kinetic mechanism in the two-phase region and an elementary kinetic mechanism in the gas region. The model has been applied to …

Falling Down, David Pace

Inscape

No abstract provided.

Paradise In Poverty, Visti Favrholt

The Bridge

Junction City, in the early thirties, was a sleepy, small

town located in the Willamette Valley of Oregon. With a

population of only a few hundred, it could hardly be

called a city. But the forefathers had visions of a major rail way

and highway junction at this location, providing prosperity

and a great future for all. As it was, the railway went

straight through town and trains seldom stopped there.

Full Issue

The Bridge

No abstract provided.

Full Issue

Brigham Young University Prelaw Review

No abstract provided.

Conversion Of Coal Tar To Soot During Coal Pyrolysis In A Post-Flame Environment, Thomas H. Fletcher, Jinliang Ma, Brent W. Webb

Faculty Publications

Coal pyrolysis experiments were performed in the postflame region of a CH4/H2/air flat-flame burner operating under fuel-rich conditions, where the temperature and gas compositions were similar to those in the near-burner region of a large-scale coal-fired furnace. Volatiles released from the coal particles formed a cloud of soot particles at high temperatures in the absence of oxygen. The soot particles in the cloud were collected at different residence times using a water-cooled, nitrogen-quenched suction probe. Test variables included the reaction temperature and coal type. Soot yields in terms of weight percentage of dry ash-free coal were measured based on bulk …

Chemical Structure Of Coal Tar During Devolatilization, Thomas H. Fletcher, Mathew Watt

Faculty Publications

Three coals of different rank were pyrolyzed in a drop-tube reactor at a maximum temperature of 900 K and a residence time of 160 ms. The coal and char were analyzed with solid-state ¹³C NMR. The tar was dissolved in deuterated methylene chloride. It was found that the tar was only partially soluble in CD₂Cl₂. The nonsoluble tar portion was analyzed in the same manner as the coal and char, while the soluble tar portion was analyzed using a recently developed high-resolution 13CNMRtechnique developed for liquid phases. The tar structure was found to be significantly …

Chen, W., L. D. Smoot, S. C. Hill, And T. H. Fletcher, “Global Rate Expression For Nitric Oxide Reburning. Part 2,” Energy And Fuels, 10, 1046-1052 (1996)., Wei Chen, L Douglas Smoot, Scott C. Hill, Thomas H. Fletcher

Faculty Publications

An investigation of a global reburning-NO reaction, sum(C_iH_j) + NO => HCN + . . ., which is a reduction pathway of nitric oxide (NO) by reaction with gaseous hydrocarbons, was conducted. The global reburning-NO rate expression was deduced from a combination of elemental reactions. The global rate expression and its rate constants were then determined by correlating predicted species profiles from simple hydrocarbon flames. This global reburning-NO rate constant can be expressed as 2.7x10⁶ exp(-18,800/RT) (gmol/cm³ s). This expression and constants are applicable to atmospheric pressure with an equivalence ratio range of 1.0-2.08 …

A Computational Method For Determining Global Fuel-No Rate Expressions. Part 1, Wei Chen, L Douglas Smoot, Thomas H. Fletcher, Richard D. Boardman

Faculty Publications

Global chemical reaction rates used in the modeling of NO_x formation in comprehensive combustion codes have traditionally been obtained through correlation of experimental data. In this paper, a computational approach for obtaining global rates is presented. Several premixed flames were simulated, and sensitivity analysis of species concentration profiles was used to suggest global pathways in fuel-nitrogen conversion to NO. Based on these analyses, the global reaction rates were formulated. The predicted species concentration profiles and their derivatives were then used in the determination of the global rate constants. The correlation of rate constants for the two fuel-NO global rates …

Experiments In The Coordinated Control Of An Underwater Arm/Vehicle System, Timothy W. Mclain, Stephen M. Rock, Michael J. Lee

Faculty Publications

The addition of manipulators to small autonomous underwater vehicles (AUVs) can pose significant control challenges due to hydrodynamic interactions between the arm and the vehicle. Experiments conducted at the monterey Bay Aquarium Research Institute (MBARI) using the OTTER vehicle have shown that dynamical interactions between an arm and a vehicle can be very significant. For the experiments reported in this paper, a single-link "arm" was mounted on OTTER. Tests showed that for 90-degree, two-second repetitive slews of the arm, the vehicle would move as much as 18 degrees in roll and 14 degrees in yaw when no vehicle control was …

Kinetic Analysis Of The Fate Of Nitric Oxide Synthesized By Macrophages In Vitro, Randy S. Lewis, Snait Tamir, Steven R. Tannenbaum, William M. Deen

Faculty Publications

To investigate the fate of nitric oxide (NO) synthesized by activated macrophages, the concentrations of NO and its principal reaction products, nitrite (NO2-) and nitrate (NO3-), were measured as a function of time in suspension cultures of RAW264.7 macrophages attached to microcarrier beads. Synthesis of NO became evident 2-5 h after stimulation of the cells, and steady concentrations of NO were achieved after about 9 h. The appearance of NO in the extracellular fluid coincided with the appearance of NO2- and NO3-, which were formed thereafter at approximately equal and constant rates. Using a kinetic model based on rate constants …

A Massively Parallel Computation Strategy For Fdtd: Time And Space Parallelism Applied To Electromagnetics Problems, Michael A. Jensen, Amir Fijany, Yahya Rahmat-Samii, Jacob Barhen

Faculty Publications

We present a novel strategy for incorporating massive parallelism into the solution of Maxwell's equations using finite-difference time-domain methods. In a departure from previous techniques wherein spatial parallelism is used, our approach exploits massive temporal parallelism by computing all of the time steps in parallel. Furthermore, in contrast to other methods which appear to concentrate on explicit schemes such as Yee's (1966) algorithm, our strategy uses the implicit Crank-Nicolson technique which provides superior numerical properties. We show that the use of temporal parallelism results in algorithms which offer a massive degree of coarse grain parallelism with minimum communication and synchronization …

Integrating Reconstructed Scatterometer And Advanced Very High Resolution Radiometer Data For Tropical Forest Inventory, David G. Long, Perry J. Hardin

Faculty Publications

A scientific effort is currently underway to assess tropical forest degradation and its potential impact on Earth's climate. Because of the large continental regions involved, Advanced Very High Resolution Radiometer (AVHRR) imagery and its derivative vegetation index products with resolutions between 1 and 12 km are typically used to inventory the Earth's equatorial vegetation. Archival AVHRR imagery is also used to obtain a temporal baseline of historical forest extent. Recently however, 50-km Seasat-A Scatterometer (SASS) Ku-band imagery (acquired in 1978) has been reconstructed to = 4-km resolution, making it a supplement to AVHRR imagery for historical vegetation assessment. In order …

Classification Of The Riparian Vegetation Along A 6-Km Reach Of The Animas River, Southwestern Colorado, Gillian M. Walford, William L. Baker

Great Basin Naturalist

Riparian ecosystems are important components of landscapes, particularly because of their role in biodiversity. A first step in using a "coarse-filter" approach to riparian biodiversity conservation is to determine the kinds of riparian ecosystems. These ecosystems vary substantially in plant species composition along a single river reach, as well as between rivers, and yet the river-reach scale has received little attention. We sampled the vascular plant composition of 67 contiguous patches of riparian vegetation along the reach of the Animas River, in southwestern Colorado's San Juan Mountains, that is relatively undisturbed by human land uses. Using cluster analysis and detrended …

Full Issue, Vol. 55 No. 4

Great Basin Naturalist

No abstract provided.

A Vision For The World: The Life And Work Of Marija Gimbutes, Joan Marler

Comparative Civilizations Review

No abstract provided.

Gentle Father, George Bennion

BYU Studies

No abstract provided.

Full Issue

Brigham Young University Prelaw Review

No abstract provided.

Corporation Of The Presiding Bishop V. Amos, Matthew David Dimick

Brigham Young University Prelaw Review

The Supreme Court has long sought for a consistent principle in constitutional theory that will "be a master principle that can guide the interpretation of both religion clauses" (Tushnet, 1691). Indeed, at times both the Establishment Clause and the Free Exercise Clause seem to contradict. Such an instance arose in Corporation of the Presiding Bishop v. Amos. In this case the Court applied the religious accommodation principle to allow a religious group the right to remain an autonomous entity thereby maintaining protection guaranteed under the Free Exercise Clause, also recognizing "that the government may (and sometimes must) accommodate religious practices …

A Pixel Scale Digital-To-Analog Converter Array For Liquid Crystal On Vlsi Displays, Gregory P. Nordin, S. T. Kowel, J. H. Kulick, R. G. Lindquist, P. J. Nasiatka, A. Thomsen

Faculty Publications

A pixel scale digital to analog converter and driver for liquid crystal (LC) cells is presented. The circuit is a compact CMOS logic gate that sums pulse density modulation (pdm) signals. Low pass filtering of the pdm signal is 'done by the LC material. The circuit is suitable to implement large arrays of converters as, for example, in display applications. It is applicable in LC on silicon displays where gray scale data are stored and converted at each pixel site. Advantages over the commonly used active matrix technology include the removal of all analog circuitry, no need for refresh, reduced …

Electromagnetic Boundary Conditions And Differential Forms, Karl F. Warnick, Richard H. Selfridge, David V. Arnold

Faculty Publications

A new representation for electromagnetic boundary conditions involving a boundary projection operator defined using the interior and exterior products of the calculus of differential forms is developed. This operator expresses boundary conditions for fields represented by differential forms of arbitrary degree. With vector analysis, the field intensity boundary conditions require the cross product, whereas the flux boundary conditions use the inner product. With differential forms, the field intensity and flux density boundary conditions are expressed using a single operator. This boundary projection operator is readily applied in practice, so that this work extends the utility of the calculus of differential …

An Integrated Framework For Learning And Reasoning, Christophe G. Giraud-Carrier, Tony R. Martinez

Faculty Publications

Learning and reasoning are both aspects of what is considered to be intelligence. Their studies within AI have been separated historically, learning being the topic of machine learning and neural networks, and reasoning falling under classical (or symbolic) AI. However, learning and reasoning are in many ways interdependent. This paper discusses the nature of some of these interdependencies and proposes a general framework called FLARE, that combines inductive learning using prior knowledge together with reasoning in a propositional setting. Several examples that test the framework are presented, including classical induction, many important reasoning protocols and two simple expert systems.

More On The Silver Plates From Lehi's Jerusalem, William J. Adams Jr.

Journal of Book of Mormon Studies

Michael D. Coogan identifies the silver plates found in a Jerusalem burial site as one of the ten most significant finds for biblical archaeology because “they are our earliest witness to the text of the Bible.”

Taking Uncle Toby Home, Rochelle A. Fankhauser

BYU Studies

No abstract provided.

Liquid Crystal-On-Silicon Implementation Of The Partial Pixel Three-Dimensional Display Architecture, M. W. Jones, Gregory P. Nordin, M. Friends, S. T. Kowel, J. H. Kulick, R. G. Lindquist, P. J. Nasiatka

Faculty Publications

We report the implementation of a liquid crystal-on-silicon, three-dimensional 13-D2 diffractive display based on the partial pixel architecture. The display generates multiple stereoscopic images that are perceived as a static 3-D scene with one-dimensional motion parallax in a manner that is functionally equivalent to a holographic stereogram. The images are created with diffraction gratings formed in a thin liquid crystal layer by fringing electric fields from transparent indium tin oxide interdigitated electrodes. The electrodes are controlled by an external drive signal that permits the 3-D scene to be turned on and off. The display has a contrast ratio of 5.8, …

Real-Time Three-Dimensional Display Based On The Partial Pixel Architecture, Gregory P. Nordin, M. W. Jones, S. T. Kowel, J. H. Kulick, R. G. Lindquist

Faculty Publications

We previously reported several static three-dimensional (3-D) display implementations of the partial pixel architecture [J. Opt. Soc. Am. A 12, 73 (1995)]. We report herein our f irst real-time 3-D display based on this architecture. The display is functionally equivalent to a real-time holographic stereogram. It is autostereoscopic and provides horizontal motion parallax. The display device is composed of a diffractive optical element (fabricated with standard photolithographic techniques) and a separate conventional liquidcrystal display. The display has been used to play back a precomputed animated 3-D scene at video frame rates using a standard VGA video output.

From Visiting Scholar To Immigrant: A Memoir, Gustav T. Durrer

Swiss American Historical Society Review

In younger years, with youthful optimism, one tends to project the future on a fairly straight line. Life usually alters that course. Circumstances change, and we change with them. Events in and around us shape our destiny. Roadblocks and crossroads force us to choose an unplanned route. 1939-45 was such a time when many lives were drastically changed, due to the dramatic developments in Europe and the Far East. These events were to alter the course of my life also.