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1999

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Articles 721 - 750 of 2348

Full-Text Articles in Physical Sciences and Mathematics

Effect Of Culturing Time And Hormonal Combinations On Organogenesis Of Date Palm (Phoenix Dactylifera L., Cv. Khnazi) In Vitro, Helal Homaid S. Al-Kaabi Jun 1999

Effect Of Culturing Time And Hormonal Combinations On Organogenesis Of Date Palm (Phoenix Dactylifera L., Cv. Khnazi) In Vitro, Helal Homaid S. Al-Kaabi

Theses

Date palm (Phoenix dactylifera L.) monocotyledon dioecious tree is one of the most important fruit crop trees in the Arabian Gulf region in general and in the UAE in particular.

Date palm is propagated sexually by seeds or vegetative by offshoots. Seed propagation is not appropriate for commercial production because of the high genetic heterozygosity, which resulted in not true-to-type male and female seedlings. The vegetative propagation utilizing offshoots is slow and inefficient for rapidly growing demands of the date industry. Therefore, it seems essential to use plant tissue culture techniques for propagating and producing date palms.

The present …


Growth And Performance Of Some Forage And Landscape Species Directly Irrigated With Saline Water, Mohammed Abdul Muhsen Ali Salem Jun 1999

Growth And Performance Of Some Forage And Landscape Species Directly Irrigated With Saline Water, Mohammed Abdul Muhsen Ali Salem

Theses

This work aimed to study the growth and physiological performance of SIX forage and

landscape species grown in Nahshalah farm , Zayed International Agricultural and Environmental Research Program Among these species 4 mangrove plants were first Introduced to U. A. E cli mate and soils In addition, Acacia ampliceps and Atriplex amnicola The study covered 1- 7 years plants were irrigated With 25 ppt . Saline water. The study investigated also the changes in the soil chemical characteristics and mineral composition during the 1 -9 years direct irrigation with saline water

The growth performance was measured based on the sufficient …


Influence Of Rare Regions On Magnetic Quantum Phase Transitions, Rajesh S. Narayanan, Thomas Vojta, Dietrich Belitz, Theodore R. Kirkpatrick Jun 1999

Influence Of Rare Regions On Magnetic Quantum Phase Transitions, Rajesh S. Narayanan, Thomas Vojta, Dietrich Belitz, Theodore R. Kirkpatrick

Physics Faculty Research & Creative Works

The effects of quenched disorder on the critical properties of itinerant quantum magnets are considered. Particular attention is paid to locally ordered rare regions that are formed in the presence of quenched disorder even when the bulk system is still in the nonmagnetic phase. It is shown that these local moments or instantons destroy the previously found critical fixed point in the case of antiferromagnets. In the case of itinerant ferromagnets, the critical behavior is unaffected by the rare regions due to an effective long-range interaction between the order parameter fluctuations.


First Order Transitions And Multicritical Points In Weak Itinerant Ferromagnets, Dietrich Belitz, Theodore R. Kirkpatrick, Thomas Vojta Jun 1999

First Order Transitions And Multicritical Points In Weak Itinerant Ferromagnets, Dietrich Belitz, Theodore R. Kirkpatrick, Thomas Vojta

Physics Faculty Research & Creative Works

It is shown that the phase transition in low-Tc clean itinerant ferromagnets is generically of first order, due to correlation effects that lead to a nonanalytic term in the free energy. A tricritical point separates the line of first order transitions from Heisenberg critical behavior at higher temperatures. Sufficiently strong quenched disorder suppresses the first order transition via the appearance of a critical end point. A semiquantitative discussion is given in terms of recent experiments on MnSi, and predictions for other experiments are made.


Molybdenum Accumulation In Cariaco Basin Sediment Over The Past 24 K.Y.: A Record Of Water-Column Anoxia And Climate, Walter E. Dean, David Z. Piper, Larry C. Peterson Jun 1999

Molybdenum Accumulation In Cariaco Basin Sediment Over The Past 24 K.Y.: A Record Of Water-Column Anoxia And Climate, Walter E. Dean, David Z. Piper, Larry C. Peterson

United States Geological Survey: Staff Publications

Molybdenum (Mo) concentrations in a sediment core from the Cariaco basin on the Venezuelan continental shelf can be partitioned between a marine fraction and a terrigenous fraction. The accumulation rate of the marine fraction of Mo increased abruptly 15 000 calendar years ago (15 ka), from <0.5 mg • cm-2 • yr-1 to >4 μg • cm-2 • yr-1, and then decreased abruptly at 9 ka. The accumulation rate remained high throughout this 6 k.y. period, but exhibited maxima at 15–14 and 12.5 ka, corresponding in time to meltwater pulse IA into the Gulf of Mexico and the onset …


Piezoelectric And Pyroelectric Properties Of Ferroelectric Langmuir-Blodgett Polymer Films, A.V. Bune, Chuanxing Zhu, Stephen Ducharme, L.M. Blinov, V.M. Fridkin, S.P. Palto, N.N. Petukhova, S.G. Yudin Jun 1999

Piezoelectric And Pyroelectric Properties Of Ferroelectric Langmuir-Blodgett Polymer Films, A.V. Bune, Chuanxing Zhu, Stephen Ducharme, L.M. Blinov, V.M. Fridkin, S.P. Palto, N.N. Petukhova, S.G. Yudin

Stephen Ducharme Publications

The piezoelectric and pyroelectric responses of ferroelectric Langmuir–Blodgett polymer films are less than the largest values measured with bulk films of the same composition. The films of the crystalline copolymer poly(vinylidene fluoride trifluoroethylene) fabricated by the Langmuir–Blodgett technique are 30 ML thick (15 nm) and are highly crystalline and oriented with polarization perpendicular to the film. Both piezoelectric and pyroelectric measurements show reversible ferroelectric switching. The films are suitable for use in pyroelectric infrared imaging and in piezoelectric acoustic transducers.


Quality Assurance And The Scientific Method, Ray T. Sterner Jun 1999

Quality Assurance And The Scientific Method, Ray T. Sterner

United States Department of Agriculture Wildlife Services: Staff Publications

As all RMRCSQA members know, during the 1980s the Environmental Protection Agency (EPA) and the Food a d Drug Administration (FDA) implemented 40 Code of Federal Regulations (CFR) Parts 160/792 and 21 CFR Part 58, respectively. These regulations outlined GLPs for data data collections needed to register pesticides, toxic substances, and drugs in the U.S.; QA concepts fix study oversight Were also described in these parts (see Sterner and Fagerstone, 1997). What you may not have considered is the relationship of these regulations to the scientific method.


Multiobjective Evolutionary Algorithms: Classifications, Analyses, And New Innovations, David A. Van Veldhuizen Jun 1999

Multiobjective Evolutionary Algorithms: Classifications, Analyses, And New Innovations, David A. Van Veldhuizen

Theses and Dissertations

This research organizes, presents, and analyzes contemporary Multiobjective Evolutionary Algorithm (MOEA) research and associated Multiobjective Optimization Problems (MOPs). Using a consistent MOEA terminology and notation, each cited MOEAs' key factors are presented in tabular form for ease of MOEA identification and selection. A detailed quantitative and qualitative MOEA analysis is presented, providing a basis for conclusions about various MOEA-related issues. The traditional notion of building blocks is extended to the MOP domain in an effort to develop more effective and efficient MOEAs. Additionally, the MOEA community's limited test suites contain various functions whose origins and rationale for use are often …


Detection Of Gradual Transitions Through Temporal Slice Analysis, Chong-Wah Ngo, T. C. Pong, R. T. Chin Jun 1999

Detection Of Gradual Transitions Through Temporal Slice Analysis, Chong-Wah Ngo, T. C. Pong, R. T. Chin

Research Collection School Of Computing and Information Systems

In this paper, we present approaches for detecting camera cuts, wipes and dissolves based on the analysis of spatio-temporal slices obtained from videos. These slices are composed of spatial ly and temporal ly coherent regions which can be perceived as shots. In the proposed methods, camera breaks are located by performing color-texture segmentation and statistical analysis on these video slices. In addition to detecting camera breaks, our methods can classify the detected breaks as camera cuts, wipes and dissolves in an efficient manner


The Weierstrass–Enneper System For Constant Mean Curvature Surfaces And The Completely Integrable Sigma Model, Paul Bracken, A. M. Grundland, L. Martina Jun 1999

The Weierstrass–Enneper System For Constant Mean Curvature Surfaces And The Completely Integrable Sigma Model, Paul Bracken, A. M. Grundland, L. Martina

School of Mathematical & Statistical Sciences Faculty Publications

The integrability of a system which describes constant mean curvature surfaces by means of the adapted Weierstrass–Enneper inducing formula is studied. This is carried out by using a specific transformation which reduces the initial system to the completely integrable two-dimensional Euclidean nonlinear sigma model. Through the use of the apparatus of differential forms and Cartan theory of systems in involution, it is demonstrated that the general analytic solutions of both systems possess the same degree of freedom. Furthermore, a new linear spectral problem equivalent to the initial Weierstrass–Enneper system is derived via the method of differential constraints. A new procedure …


Evolution Of Recurrent Cascade Correlation Networks With Ditributed Collaborative Species, Ghada Nasr Aly Jun 1999

Evolution Of Recurrent Cascade Correlation Networks With Ditributed Collaborative Species, Ghada Nasr Aly

Archived Theses and Dissertations

No abstract provided.


Routing And Caching Mechanisms For Mobile Ip Networks, Baher Ali Esmat Jun 1999

Routing And Caching Mechanisms For Mobile Ip Networks, Baher Ali Esmat

Archived Theses and Dissertations

No abstract provided.


An Auditing Capability On Top Of The Java Virtual Machine (Jvm), Margo Fouad Fawzi Hanna Jun 1999

An Auditing Capability On Top Of The Java Virtual Machine (Jvm), Margo Fouad Fawzi Hanna

Archived Theses and Dissertations

No abstract provided.


Visual Constraint Programming Environment For Configuration Problems, Rania A/Hamid El Sayed Jun 1999

Visual Constraint Programming Environment For Configuration Problems, Rania A/Hamid El Sayed

Archived Theses and Dissertations

No abstract provided.


Cadmium, Chromium And Lead In Environmental Samples : Speciation And Determination, Hsing-Hui Yu May 1999

Cadmium, Chromium And Lead In Environmental Samples : Speciation And Determination, Hsing-Hui Yu

Dissertations

Heavy metals are important contaminants in many environmental media. This work focuses on the improvement of current methods for water and sediment analysis for three metals, cadmium, chromium and lead. Batch ion exchange was used for water speciation and a microwave assisted sequential extraction scheme was developed for sediment characterization. The developed methods were applied to a group of environmental samples.

The exchangeable species of these metals in water were preconcentrated on ion exchange resins. These include the bioavailable free ions and weakly complexed ions. Metals sorbed on particles and strongly complexed ions, less bioavailable, were eliminated. The method was …


Applications Of A Microtrap For On-Line Monitoring Of Volatile Organics, Chaohua Feng May 1999

Applications Of A Microtrap For On-Line Monitoring Of Volatile Organics, Chaohua Feng

Dissertations

Microtrap is made by packing a narrow metal tubing with adsorbents. The advantage of a microtrap is that it can be heated and cooled in the order of seconds. It has been used previously as a concentration cum injection device for on-line gas chromatography and also monitoring non-methane organic carbon in air emissions. In this research breakthrough and desorption characteristics of the microtrap were studied. A two-stage microtrap system was developed to reduce breakthrough while making sharp injection for GC separation. Microtrap was also used as a concentrator cum injector in on-line mass spectrometry. Finally, a microtrap based, continuous non-methane …


Development Of Membrane Extraction Systems For Measuring Trace Level Organic Compounds In Water, Xuemei Guo May 1999

Development Of Membrane Extraction Systems For Measuring Trace Level Organic Compounds In Water, Xuemei Guo

Dissertations

The presence of volatile organic compounds (VOCs) in ground and surface water resources poses a threat to public health. The measurement of these trace level contaminants in water is of significant importance. Conventional methods for analysis of trace volatile organic compounds in water include purge and trap, head space analysis, and solid phase microextraction (SPME). While these are excellent laboratory techniques, none of them can be used for continuous, on-line monitoring of water streams. Membrane separation of organic compounds from water provides an exciting possibility for on-line extraction and analysis. In previous investigations, water continuously flowed on the feed side …


Developing Techniques For Enhancing Comprehensibility Of Controlled Medical Terminologies, Huanying Gu May 1999

Developing Techniques For Enhancing Comprehensibility Of Controlled Medical Terminologies, Huanying Gu

Dissertations

A controlled medical terminology (CMT) is a collection of concepts (or terms) that are used in the medical domain. Typically, a CMT also contains attributes of those concepts and/or relationships between those concepts. Electronic CMTs are extremely useful and important for communication between and integration of independent information systems in healthcare, because data in this area is highly fragmented. A single query in this area might involve several databases, e.g., a clinical database, a pharmacy database, a radiology database, and a lab test database.

Unfortunately, the extensive sizes of CMTs, often containing tens of thousands of concepts and hundreds of …


Porting The Sisal Functional Language To Distributed-Memory Multiprocessors, Jui-Yuan Ku May 1999

Porting The Sisal Functional Language To Distributed-Memory Multiprocessors, Jui-Yuan Ku

Dissertations

Parallel computing is becoming increasingly ubiquitous in recent years. The sizes of application problems continuously increase for solving real-world problems. Distributed-memory multiprocessors have been regarded as a viable architecture of scalable and economical design for building large scale parallel machines. While these parallel machines can provide computational capabilities, programming such large-scale machines is often very difficult due to many practical issues including parallelization, data distribution, workload distribution, and remote memory latency.

This thesis proposes to solve the programmability and performance issues of distributed-memory machines using the Sisal functional language. The programs written in Sisal will be automatically parallelized, scheduled and …


Flame Dynamics In Steady Strained Flows, Zili Huang May 1999

Flame Dynamics In Steady Strained Flows, Zili Huang

Dissertations

In this dissertation, the response of a premixed flame to time-dependent strained flow fields is investigated. Because of the potential application to turbulent combustion modeling, the main focus is on the particular case of a flame in stagnation point flow with an imposed oscillatory strain rate. The flame is modeled as a hydrodynamic discontinuity separating burned from unburned gasses. To complete the formulation of the problem, conditions relating the fluid variables across the flame front are needed, as is a flame speed equation that determines the evolution of the discontinuity. These conditions are derived through asymptotic analysis of the flame …


Dynamical Systems Associated With Particle Flow Models : Theory And Numerical Methods, Roman V. Samulyak May 1999

Dynamical Systems Associated With Particle Flow Models : Theory And Numerical Methods, Roman V. Samulyak

Dissertations

A new class of integro - partial differential equation models is derived for the prediction of granular flow dynamics. These models are obtained using a novel limiting averaging method (inspired by techniques employed in the derivation of infinite-dimensional dynamical systems models) on the Newtonian equations of motion of a many-particle system incorporating widely used inelastic particle-particle force formulas. By using Taylor series expansions, these models can be approximated by a system of partial differential equations of the Navier-Stokes type. Solutions of the new models for granular flows down inclined planes and in vibrating beds are compared with known experimental and …


Automatic Document Classification And Extraction System (Adoces), Xuhong Li May 1999

Automatic Document Classification And Extraction System (Adoces), Xuhong Li

Dissertations

Document processing is a critical element of office automation. Document image processing begins from the Optical Character Recognition (OCR) phase with complex processing for document classification and extraction. Document classification is a process that classifies an incoming document into a particular predefined document type. Document extraction is a process that extracts information pertinent to the users from the content of a document and assigns the information as the values of the “logical structure” of the document type. Therefore, after document classification and extraction, a paper document will be represented in its digital form instead of its original image file format, …


Knowledge Management For Texpros, Jianshun Hu May 1999

Knowledge Management For Texpros, Jianshun Hu

Dissertations

Most of the document processing systems today have applied Al technologies to support their system intelligent behaviors. For the application of Al technologies in such systems, the core problem is how to represent and manage different kinds of knowledge to support their inference engine components' functionalities. In other words, knowledge management has become a critical issue in the document processing systems. In this dissertation, within the scope of the TEXt PROcessing System (TEXPROS), we identify knowledge of various kinds that are applicable in the system. We investigate several problems of managing this knowledge and then develop a knowledge base for …


Pattern Discovery In Trees : Algorithms And Applications To Document And Scientific Data Management, Chia-Yo Chang May 1999

Pattern Discovery In Trees : Algorithms And Applications To Document And Scientific Data Management, Chia-Yo Chang

Dissertations

Ordered, labeled trees are trees in which each node has a label and the left-to-right order of its children (if it has any) is fixed. Such trees have many applications in vision, pattern recognition, molecular biology and natural language processing.

In this dissertation we present algorithms for finding patterns in the ordered labeled trees. Specifically we study the largest approximately common substructure (LACS) problem for such trees. We consider a substructure of a tree T to be a connected subgraph of T. Given two trees T1, T2 and an integer d, the LACS problem is to find …


A New-Generation Class Of Parallel Architectures And Their Performance Evaluation, Qian Wang May 1999

A New-Generation Class Of Parallel Architectures And Their Performance Evaluation, Qian Wang

Dissertations

The development of computers with hundreds or thousands of processors and capability for very high performance is absolutely essential for many computation problems, such as weather modeling, fluid dynamics, and aerodynamics. Several interconnection networks have been proposed for parallel computers. Nevertheless, the majority of them are plagued by rather poor topological properties that result in large memory latencies for DSM (Distributed Shared-Memory) computers. On the other hand, scalable networks with very good topological properties are often impossible to build because of their prohibitively high VLSI (e.g., wiring) complexity. Such a network is the generalized hypercube (GH). The GH supports full-connectivity …


Modeling Controlled Vocabularies Using Oodbs And Multilevel Area Diagrams, Li-Min Liu May 1999

Modeling Controlled Vocabularies Using Oodbs And Multilevel Area Diagrams, Li-Min Liu

Dissertations

A Controlled Vocabulary (CV) is a software system of domain knowledge that consolidates and unifies the terminology of a large application domain. With a common, centralized CV, costly and time-consuming translations can be eliminated between pairs of organizations and pairs of software systems. Unfortunately, the more knowledge we put into a CV, the harder it is to understand and maintain it. In this dissertation, a comprehensive theoretical methodology for modeling CVs using Object-Oriented Database (OODB) technology is presented. We present two methods for representing a semantic network CV as an equivalent OODB, which we call an Object-Oriented Vocabulary Repository (OOVR). …


An Examination Of The Self-Perceptions Of The Physical Environment And Psychological Health Of Latina Women Living In The St. Columbia Neighborhood Of Newark, New Jersey, Veronica Maria Maya May 1999

An Examination Of The Self-Perceptions Of The Physical Environment And Psychological Health Of Latina Women Living In The St. Columbia Neighborhood Of Newark, New Jersey, Veronica Maria Maya

Theses

A correlation between perceptions of environmental quality and psychological health has been established in a sample of Latina women. Three psychological scales exist to measure psychological constructs such as learned helplessness, hopelessness, and selfesteem. These three scales have been used in conjunction with an environmental survey designed to capture the perceptions of the sample to their physical environment.

The mean of scores for each psychological construct in the Latina sample were compared to the mean of scores for these constructs in independent samples of oncology, hemodialysis, and spinal cord injured patients being treated for depression. This comparison yields the following …


Sustainable Green Manufacturing Of Energetic Materials, Ted Alex Formeza May 1999

Sustainable Green Manufacturing Of Energetic Materials, Ted Alex Formeza

Theses

Pollution from manufacturing processes of the major energetic materials currently used in the U.S., 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-1,3,5,7 tetraazacyclooctane (HMX) was briefly evaluated. It was found that acetic acid was a major pollutant. It appeared that the British Process could be controlled to reduce the polluting effluents better than the Bachmann Process used in the U.S. Most of the effort for producing the next generation of energetic materials is currently centered around the production of 1,3,3-trinitroazetidine (TNAZ). We evaluated five synthetic routes for producing TNAZ. We reduced the number of potential processes by carefully considering possible changes in the schemes that …


History Of Oxygenated Gasoline Use In New Jersey 1992-1998, Jean Niebuhr Borne May 1999

History Of Oxygenated Gasoline Use In New Jersey 1992-1998, Jean Niebuhr Borne

Theses

New Jersey has been required to use oxygenated gasoline from November 1 to March 30 since 1992 in order to reduce carbon monoxide from vehicles. This requirement was part of the Clean Air Act Amendments of 1990. For the past six winters, New Jersey has utilized gasoline with methyl butyl tertiary ether, MTBE, as the oxygenate. In New Jersey, and in many states across the country, health complaints were reported after oxygenated fuel started flowing from gas pumps.

Oxybusters is a grassroots organization dedicated to the removal of oxygenated gasoline off the market. The group has pressured Governor Whitman to …


Recasting Cohn's Many Sorted Logic Into A Constrained Logic, Christopher Brendan Koelbl May 1999

Recasting Cohn's Many Sorted Logic Into A Constrained Logic, Christopher Brendan Koelbl

Theses

The use of a many sorted logic for theorem proving carries many advantages over a traditional unsorted logic. By placing restrictions on the search space, a many sorted logic can significantly reduce the amount steps in the resolution process. However, as a logic becomes more efficient, it increases in complexity.

One of these efficient log ics is Cohn's Many Sorted Logic, LLAMA. It uses complex data structures such as the sort lattice and sort arrays to maintain information about the sorts. Recasting LLAMA into Bürckert's constrained logic will keep the functionality of LLAMA while using a format that reduces the …