Digital Commons Network^™

Immobilization Of Glucose Oxidase And Urease In Hydrogel Matrices, İhsan Gürel, M.Yakup Arica, Vasıf Hasirci

Turkish Journal of Chemistry

Immobilization of glucose oxidase and urease in hydrogels of 2-hydroxyethyl methacrylae, and N-vinyl pyrrolidone (NVP) was achieved by irradiation (using UV kand \gamma- rays). The effect of radiation on entrapment efficiencies, retention of activities and swelling rates was obtained. To optimize the system, duration of exposure, reaction temperature, co-monomer concentrations, initiator and cross linker compositions were varied. The repeated reusability of the generated products was also tested. It was found that\gamma-irradiation at very low temperatures did not have a detrimental effect on the enzyme activity. Incorporation of more hydrophilic monomer (NVP), influenced matrix morphology and entrapment efficiencies and retained enzyme …

Photoelectron Spectroscopy: A Tool In Sorption Studies, Şefik Süzer, Hasan N. Erten

Turkish Journal of Chemistry

Photoelectron spectroscopy using AlK\alpha (h\nu=1486.3 eV) has been applied to study the sorption of Cs^+, Sr^{2+}, Ba^{2+}, Zn^{2+} and Co^{2+} on magnesite kaolinite, smectite and chlorite. From the observed intensities of photoelectron peaks it was determined that in magnesite the sorption affinity of the above ions follow the order: Ba^{2+}>Co^{2+}\congSr^{2+}\congZn^{2+}>Cs^+. The order for the sorption of Ba^{2+} and Cs^+ are also determined as chlorite>magnesite>smectite>kaolinite and smectite>chlorite\congkaolinite>magnesite, respectively.

A Topological Approach To The Stabilities Of Isomeric Hückel And Mobius Type Cyclacenes, Lemi Türker

Turkish Journal of Chemistry

Within the constraints of Hückel molecular orbital theory, Hückel and Mobius type cyclacenes were investigated in terms of their angle of total \pi-electron energy, O_{\pi}, and cos O_{\pi} to find out how structural changes affect the stabilities. It has been theoretically deduced that as the number of benzenoid rings (R) increases the isomeric Hückel and Mšbius type cyclacenes should have comparable stabilities, although for low values of R odd-Hückel type and even-Mobius type are predicted to be more stable.

Hydrolysis And Condensation Reactions Of Methacrylate-Modified Aluminum Alkoxides, Ertuğrul Arpaç, Efraim Avşar

Turkish Journal of Chemistry

The hydrolysis of aluminum tri-sec-butoxide and compounds obtained by substituting the larger functional groups for the present alkly groups in Al(O-sec-Bu)_3, and the reaction of these products with a polymerizable organic ligand, i.e. methacrylic acid, were studied together with the hydrolysis reactions of the final products. A good method of preparing high-tech materials and new composites uses organo-substituted silicon esters and/or alkoxides of various elements in a polycondensation process. Introducing a suitable organic network into the inorganic backbone gives desirable properties in new coating materials. The preparation of such materials is possible via the hydrolysis of metal alkoxides. Usually, different …

Potentiometric And Spectroscopic Determinaton Of Acid Dissociation Constants Of Some Phenols And Salicylic Acids, Rahmiye Aydin, Ulviye Özer, Naciye Türkel

Turkish Journal of Chemistry

The dissociation constant of the catechol derivatives 4-nitrocatechol (NCAT), 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DBHA), 3,4-dihydroxyhenylacetic acid (3,4-DPHA) and 3,4-dihydroxycinnamic acid (3,4-DHCA) were identified in 0.1M NaClO_4 ionic medium, at t=25^{\circ}C, by potentiometry. In addition, the first and second dissociation constants of the salicylic acid derivatives 5-nitrosalicylic acid (5-NSA), 4-hydroxysalicylic acid (4-HSA) 5-nitrosalicylic acid (5-HSA) were also determined by potentiometry. Furthermore, the second acid dissociation constants of these ligands were evaluated in I=0.1M NaClO_4 ionic medium, at a temperature of 25^{\circ}C by computer analysis of spectroscopic data.

The Influence Of Reading Comprehension And Other Selected Factors On Student Dropouts In An Urban Southeastern School District In Virginia, Viola Garris Morgan

Theses and Dissertations in Urban Services - Urban Education

The purpose of this research was to examine the influence of reading achievement on the dropout status. The major research question was to determine to what extent does reading comprehension influence the dropout rate after controlling for demographic and performance characteristics?

The target population consisted of 677 urban twelfth-grade students attending schools in an urban southeastern school district in the Commonwealth of Virginia. Of the 677 students, 142 were dropouts, and 535 were nondropouts. Simple and partial correlations were used to determine the relationship between variables after partialing out performance and demographic variables. In addition, the discriminant analyses were used …

The Effects Of Applied Technology Instruction On Mathematics Achievement And Career Interests Of Urban Seventh-Grade Students, Eric M. Fischer

Theses and Dissertations in Urban Services - Urban Education

The present study has been implemented to provide insight as to how, given limited resources, Technology Education curricula might be developed to best support the unique goals of an urban middle school aerospace magnet program. It was hypothesized that applied academic strategies, including interdisciplinary hands-on aerospace and computer-assisted instructional activities, would affect larger gains in mathematics achievement and would enhance career-interest development of urban seventh-grade students to a greater degree than would non-participation in such instruction. A randomized subjects, pretest-posttest control group design was used to assess treatment effects upon 71 urban seventh-grade students. Dependent variables were measured using the …

Modeling Plankton Community Structure Under Environmental Forcing On The Southeastern United States Continental Shelf, Andrew Glenn Edward Haskell

OES Theses and Dissertations

A system of coupled ordinary differential equations was developed to investigate the time-dependent behavior of phytoplankton, copepod, and doliolid populations associated with upwelling features on the outer southeastern U.S. continental shelf. Model equations describe the interactions of nitrate, ammonium, two phytoplankton size fractions, five copepod developmental stages, doliolids, and a detrital pool. Model dynamics are based primarily upon data obtained from field and laboratory experiments made for southeastern U.S. continental shelf plankton populations. Numerous simulations were performed to investigate the effects of environmental variability on the temporal distribution of the structure of resident plankton populations. Variations on a reference simulation, …

Analysis Of Repeated Measures Data Under Circular Covariance, Andrew Montgomery Hartley

Mathematics & Statistics Theses & Dissertations

Circular covariance is important in modelling phenomena in epidemiological, communications and numerous physical contexts. We introduce and develop a variety of methods which make it a more versatile tool. First, we present two classes of estimators for use in the presence of missing observations. Using simulations, we show that the mean squared errors of the estimators of one of these classes are smaller than those of the Maximum Likelihood (ML) estimators under certain conditions. Next, we propose and discuss a parsimonious, autoregressive type of circular covariance structure which involves only two parameters. We specify ML and other types of estimators …

Characterization Of Iron Oxides And Atmospheric Corrosion Of Steel, Sei Jin Oh

Physics Theses & Dissertations

The study of corrosion behavior was performed using three different analytical techniques, which provided information on the formation, development and layering of iron oxides on the corrosion products as a function of atmospheric conditions, exposure time and type of steel. In particular, the protective layer formed on weathering steel was investigated as a function of different amounts of alloying elements in the steel, atmospheric conditions and exposure times. Combined together, the results provided a better understanding of the atmospheric corrosion behavior of steel, and formed a part of database of the atmospheric corrosion characteristics.

Accurate characterization of the iron oxides …

The Effects Of Human-Computer Communication Mode, Task Complexity, And Desire For Control On Performance And Discourse Organization In An Adaptive Task, Cristina Bubb-Lewis

Psychology Theses & Dissertations

The present study examined how different communication patterns affected task performance with an adaptive interface. A Wizard-of-Oz simulation (Gould, Conti, & Hovanyecz, 1983) was used to create the impression of a talking and listening computer that acted as a teammate to help participants interact with a computer application.

Four levels of communication mode were used which differed in the level of restriction placed on human-computer communication. In addition, participants completed two sets of tasks (simple and complex). Further, a personality trait, Desire for Control (DC), was measured and participants were split into high and low groups for analysis. Dependent measures …

Distribution Of Free Marine Viruses Of Lower Chesapeake Bay And Their Effects On Life-History Parameters Of The Estuarine Copepod Acartia Tonsa Dana, Lisa A. Drake

OES Theses and Dissertations

Naturally occurring viruses are very abundant in fresh, estuarine, and marine waters, with densities on the order of 10⁵-10⁸ viruses ml^-1. Research has focused on virus effects on bacteria, cyanobacteria, and phytoplankton, as well as mechanisms of virus production and decay. However, little is known about the distribution of viruses in benthic environments or virus effects on organisms in higher trophic levels.

To determine the distribution of virus-like particles (VLPs) and bacteria in the lower Chesapeake Bay, vertical profiles of VLPs and bacteria were determined through the water column and 15-25 cm into the sediment …

An Assessment Of Hydrological Process And Landform Change: Slave River Delta, Northwest Territories, Ronald Brad Hill

Theses and Dissertations (Comprehensive)

The Slave River Delta, 61˚15'N, 113˚30'W, is located at the mouth of the Slave River in the southeast arm of Canada's Great Slave Lake. Although the delta itself lies some 1600 km downstream from the W.A.C. Bennett Dam at Hudson's Hope, British Columbia, the mean annual discharge and sediment load of the Slave River have decreased by 16% and 33% respectively since regulation. Such alterations in the Slave River flow regime have significant implications for the growth of the River Delta since the transfer of sediment to the delta front is one of the most important factors in the landform’s …

The Impact Of Glacier Recession Upon The Discharge Of The Bow River Above Banff, Alberta, 1951-1993, Christopher Dennis Hopkinson

Theses and Dissertations (Comprehensive)

Three methods have been used to explore the volumetric change of glaciers in the Bow Basin above Banff for the years 1951 to 1993. Using aerial photography, the extent of glacier covers for the two years were mapped at a scale of 1:50,000. The first volumetric calculation of glacier loss was based on inventory criteria; the second a hyposgraphic curve method based on Young’s investigations in Mistaya Basin (1991) and the third stereo air photogrammetry and DEM comparisons using computer software. These methods were applied to the highly glacierized Hector Lake catchment within the Bow Valley and then extrapolated up …

Small Mammals Of Point Pelee National Park: Protecting Biodiversity In Small Reserves (Ontario), Julie Ann Spicer

Theses and Dissertations (Comprehensive)

Habitat destruction, fragmentation and degradation have been widespread throughout southern Ontario with devastating effects on wetlands. Small reserves are all that in this highly agricultural/urban landscape to protect the biodiversity of Great Lakes Marsh and Carolinian Forest ecosystems. Small reserves are vulnerable to species loss through a host of problems related to size and as a result, the value of small reserves to conservation strategies has often been questioned. Indicator species can be used as a means of studying the conditions of complex ecosystems. In this research, small mammals were sampled in the wetlands of Point Pelee National Park as …

Reexamination Of Scarp Development Along The Niagara Escarpment, Ontario, Canada, David Walter Hintz

Theses and Dissertations (Comprehensive)

The Niagara Escarpment is generally viewed as a relict landform which shows ancient structural features and the effects of glaciation. Since it was realized that the Escarpment was not a fault, but instead a feature of erosional origin, little interest has been paid to development of the steep cliffed section of the Niagara Escarpment. This research project has several objectives. The first is an examination of the relationship between the morphology of the Escarpment and its geological units. This will include analysis of the structure and lithology of each and the geochemistry, especially, of the Queeston Formation. Associated with the …

Multiobjective Optimum Design Of Static And Seismic-Resistant Structures With Genetic Algorithm, Fuzzy Logic And Game Theory, Dan Li

Doctoral Dissertations

"The goal of this research is to develop a constrained multiobjective optimization method in the form of a robust, practical, problem-independent algorithm, and to investigate the effect of multiobjective optimization on structural design.

This research studies the properties and characteristics of multiobjective optimization and solutions. Design objectives, constraints and design variables as well as their effect on structural design and behaviors are investigated. Dynamic input energy for a multidegree-of-freedom structure is formulated. A multiobjective optimization algorithm based on game theory is developed. Fuzzy set theory is introduced to construct a fuzzy constrained environment. A Pareto genetic algorithm is developed based …

Harding University Catalog 1997-1998, Harding University

Harding Academic Catalogs

Academic catalog for the undergraduate programs at Harding University.

Conservatives, Liberals, Romantics: The Persistent Quest For Certainty In Constitutional Interpretation, Frederick Mark Gedicks

Faculty Scholarship

Despite their considerable ideological differences, "conservative originalists" such as Robert Bork and "progressive originalists" such as Michael Perry both divide the process of understanding into cognitive (or "objective") and normative (or "subjective") aspects. The determination of the original meaning of the Constitution is methodologically separated from the question how this predetermined meaning should be applied in a particular case. This places both conservative and progressive originalists squarely in the tradition of Romantic hermeneutics, which sought to overcome the uncertainty and imprecision of textual interpretation by developing a "science of interpretation" which purported to be as epistemologically reliable as the methods …

Substance Abuse At Ucc Drafting Sessions, Norman I. Silber

Hofstra Law Faculty Scholarship

A few substance abusers start down the road to addiction with a single reckless experiment. Such was the case of Professor "Doe", a consumer law specialist of my acquaintance. The entanglement of Professor Doe in the UCC drafting process began when he accepted what seemed like the harmless invitation of a friend to attend a single National Conference of Commissioners on Uniform State Laws ("NCCUSL") drafting session in1990. Session after session followed. Soon he found himself in a descending spiral-attending study groups, legislative task forces, and conference programs being held in strange cities to debate a new or revised provision …

Harmonic Oscillation In The Presence Of Multiple Damping Forces, Chris Pelto '97

Honors Projects

The relatively mundane damped harmonic oscillator is found to exhibit interesting motion once under the influence of both a velocity dependent and a Coulombic frictional damping force. Data for the decay of the amplitude as a function of time were collected on a specially prepared torsional oscillator. with a variable electromagnetic damping mechanism. An analytical solution of the appropriate equation of motion was obtained by the method of Laplace transforms. In both the limits of zero Coulombic friction and zero velocity damping, the solution reduces to the well-known answers to the problem. the solution, when plotted with the correct parameters, …

The Validity Of The B3r Entry-Level Examination For Fire Services As A Predictor For Future Job Performance, Terrance W. Gaylord '97

Honors Projects

The use of aptitude tests by public and private organizations has drawn attention from the scientific community as well as the courtroom. While theorists have argued that aptitude tests are not valid, several research studies have indicated otherwise. The current study focused on the B3R Entry-Level Examination for Fire Services, an aptitude test administered by a growing number of municipalities nationwide for selection purposes. To test the predictive ability of the exam, a criterion-related validation approach was initiated. A total of eight subjects were administered the B3R exam which was accompanied with a 21-item job performance evaluation of the employees. …

The Use Of Concept Questions To Improve Student Understanding Of Mechanics, And The Formulation Of A Hierarchical Model Of Student Understanding Of Moments Of Forces, Stuart Rowlands

School of Engineering, Computing and Mathematics Theses

The aims and objectives of the first part of the thesis are to create and evaluate a teaching package that would enable the teacher to facilitate student conceptual understanding of mechanics. The second part is to create a hierarchical model of student conceptual understanding of moments of forces. The thesis reports on the various conflicting theories and recommended teaching strategies from the research into student misconceptions, and examines the various underlying philosophical trends (for example, radical and social constructivism, the Vygotskian perspective and positivism) that have influenced the research into misconceptions in mechanics. As a result, the philosophical perspective of …

Adaptive Search And The Preliminary Design Of Gas Turbine Blade Cooling Systems, Rajkumar Roy

School of Engineering, Computing and Mathematics Theses

This research concerns the integration of Adaptive Search (AS) technique such as the Genetic Algorithms (GA) with knowledge based software to develop a research prototype of an Adaptive Search Manager (ASM). The developed approach allows to utilise both quantitative and qualitative information in engineering design decision making. A Fuzzy Expert System manipulates AS software within the design environment concerning the preliminary design of gas turbine blade cooling systems. Steady state cooling hole geometry models have been developed for the project in collaboration with Rolls Royce plc. The research prototype of ASM uses a hybrid of Adaptive Restricted Tournament Selection (ARTS) …

Steiner Trees Over Generalized Checkerboards, Meta M. Voelker '97

Honors Projects

To minimize the length of a planar network, we can build a Steiner minimal tree that is, a tree consisting of the original network points, as well as additional, strategically-placed (Steiner) points. Chung, Gardner and Graham [2] investigated building Steiner trees over grids of unit squares. We generalize their ideas to grids of rhombuses, and show that two near-optimal Steiner trees exist for each grid, one built from Steiner trees over rhombuses and one built from Steiner trees over isosceles triangles. Further, we conjecture that for grids with an odd number of layers, only the small angle of the rhombus …

The Dit Examiner: The Newspaper Of The Dublin Institute Of Technology Students' Union May, 1997, Dit:Students' Union

DIT Student Union

No abstract provided.

Diffraction From Polarization Holographic Gratings With Surface Relief In Side-Chain Azobenzene Polyesters, Izabela Naydenova, Ludmila Nikolova, Todor Todorov, N.C.R. Holme, P.S. Ramanujam, S. Hvilsted

Articles

We investigate the polarization properties of holographic gratings in side-chain azobenzene polyesters in which an anisotropic grating that is due to photoinduced linear and circular birefringence is recorded in the volume of the material and a relief grating appears on the surface. A theoretical model is proposed to explain the experimental results, making it possible to understand the influence of the different photoinduced effects. It is shown that at low intensity the polarization properties of the diffraction at these gratings are determined by the interaction of the linear and circular photobirefringences, and at larger intensity the influence of the surface …

Applications Of Acousto-Optic Demodulation And Decoding Techniques, Matthew Graham Hicks

School of Engineering, Computing and Mathematics Theses

This thesis describes the operation and performance of an acousto-optic demodulator system consisting of a laser source, an acousto-optic cell and a bi-cell detector. The bi-cell detector is made up of two photodiodes positioned side by side, separated by a small gap. Theory is developed to predict the following; the linear operating range for different gap sizes, absolute frequency sensitivity, system output in response to discrete phase changes, optimum gap size for phase demodulation, absolute descrete phase change sensitivity, the performance of the system in the presence of carrier noise and the effect of clipping the carrier signal on both …

A Geometric Approach To Modelling Interacting Populations, Jennifer M. Sharp

School of Engineering, Computing and Mathematics Theses

The purpose of this thesis is to present a different approach to the formulation of differential equation mathematical models for interacting populations. It does this through considering a geometric method. The solution to the differential equations are forced, through theuformulation, to lie on the surface of well known three-dimensional shapes. It is this that allows detailed analysis of how, and why, the solution of the equations behave as they do. The thesis firstly reviews some of the skills and techniques used in the formulation and alysis of differential equation models to give a background for some of the analysis used …

Design With Attitude: A Key World Class Method, Aj Robotham, Gn Blount

School of Engineering, Computing and Mathematics

World Class Design by implication can best be achieved by adopting world class methods. ICED conferences continue to disseminate methodologies to help make designers and design teams more effective and efficient. At ICED 95 we introduced our PAKTS model (Figure 1.) which identified the total educational needs of young engineering designers [Robotham 1995]. The five key elements of the model are Processes, Attitudes, Knowledge, Tools and Skills. Of these elements, the least developed in terms of methodologies is that of “Attitude”. This paper will give further consideration to this element and identify the qualities that a designer must develop to …