306,890 research outputs found
Effects and relationships of wheat seed size and dimensions upon yield, yield components, test weights and milling yields at different fertility levels, seed rates and environments
No full textThe experiments herein reported were conducted at College Station, Chillicothe and McGregor, Texas, with the objectives of determining the relationships of varying seed sizes and shapes in wheat to yield, yield components, test weight and milling yields under different fertility levels and seeding rates. Eighteen and 16 different strains of wheat were included in the variety comparisons in the years 1965 and 1966, respectively, at College Station. Favorable growing conditions in 1966 resulted in good yields and quality of grain. The higher fertility level did not show any significant increase over normal fertility, except in number of culms and number of kernels per spike. Varieties of different seed sizes differed significantly amongst themselves for all the yield character measurements, and it has been observed that the varietal differences were greater than the influences of seed size and shape. Correlations among yield components were high and are statistically highly significant. Kernel dimensions, number of culms per spike and 500 seed weight were highly correlated with yield. The same trends were observed in the test at Chillicothe. Though none of the characters measured were significantly correlated with test weight, there was some association with factors determining yield and an indication pointing to higher test weight for shorter and plumper kernels. ..
Multi-channel customer management: A case study in Egypt
No full textChannel management is one CRM systems component much influenced by the behaviour of customers in relation to the implementation and use of channel management CRM component. The consumers’ behaviours, preferences, perceptions and expectations are crucial for the implementation and use of channel management. Customers’ contact with the organization’s multi-channels can occur at several touch points through out customer lifecycle. Customers’ behaviours may be differentiated according to the individual or micro level, but it might also differ at an ecological or macro level of analysis (Ramaseshan et al., 2006). In this paper the author has conducted a case study in Egypt to analyze customers’ behaviours at a macro level and customers channel choices, through out the customer lifecycle. The author has used a Structurational Analysis model (Ali and Brooks, 2008) to identify the cultural factors (Ali, et al. 2008) that influence the multi-channel customer management in Egypt
Study of microfluidic measurement techniques using novel optical imaging diagnostics
No full textNovel microscale velocity and temperature measurement techniques were studied based on confocal laser scanning microscopy (CLSM) and optical serial sectioning microscopy (OSSM). Two microscopic measurement systems were developed, 1) a CLSM micro particle image velocimetry (PIV) system with a dual Nipkow disk confocal unit (CSU-10), a CW argon-ion laser and an upright microscope, and 2) an OSSM micro- particle tracking velocimetry (PTV) system with an epi-fluorescence microscope and a non-designed specimen to make a three-dimensional (3-D) diffraction particle image. The CLSM micro-PIV system shows a unique optical slicing capability allowing true depth-wise resolved vector field mapping. A comparative study is presented between the CLSM micro-PIV and a conventional epi-fluorescence micro-PIV. Both have been applied to the creeping Poiseuille flows in two different microtubes of 99-������m (Re = 0.00275) and 516-������m ID diameters (Re = 0.021). The CLSM micro-PIV consistently shows significantly improved particle image contrasts, the definition of "optical slicing" and measured flow vector fields more accurately agreeing with predictions based on the Poiseuille flow fields, compared to the conventional micro-PIV. The OSSM micro-PTV technique is applied for a 3-D vector field mapping in a microscopic flow and a Brownian motion tracking of nanoparticles. This technique modifies OSSM system for a micro-fluidic experiment, and the imaging system captures a diffracted particle image having numerous circular fringes instead of an in-focus particle image. The 3-D particle tracking is based on a correlation between the 3-D diffraction pattern of a particle and the defocus distance from a focal plane. A computational program is invented for the OSSM micro-PTV, and provides a 3-D velocity vector field with a spatial resolution of 5.16 ������m. In addition, a concept of nonintrusive thermometry is presented based on the correlation of the Brownian motion of suspended nanoparticles with the surrounding fluid temperature. Detection of fully three-dimensional Brownian motion is possible by the use of the OSSM, and the measured value of mean square displacement (MSD) is compared fairly well with Einstein's predictions
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
Get PDFFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
Multivortex micromixing: novel techniques using Dean flows for passive microfluidic mixing
Get PDFMixing of fluids at the microscale poses a variety of challenges, many of which
arise from the fact that molecular diffusion is the dominant transport mechanism in the
laminar flow regime. The unfavorable combination of low Reynolds numbers and high
P������clet numbers implies that cumbersomely long microchannels are required to achieve
efficient levels of micromixing. Although considerable progress has been made toward
overcoming these limitations (e.g., exploiting chaotic effects), many techniques employ
intricate 3-D flow networks whose complexity can make them difficult to build and
operate. In this research, we show that enhanced micromixing can be achieved using
topologically simple and easily fabricated planar 2-D microchannels by simply
introducing curvature and changes in width in a prescribed manner. This is
accomplished by harnessing a synergistic combination of (i) Dean vortices that arise in
the vertical plane of curved channels as a consequence of an interplay between inertial,
centrifugal, and viscous effects, and (ii) expansion vortices that arise in the horizontal
plane due to an abrupt increase in a conduit��������s cross-sectional area. We characterize these effects using top-view imaging of aqueous streams labeled with tracer dyes and
confocal microscopy of aqueous fluorescent dye streams, and by observing binding
interactions between an intercalating dye and double-stranded DNA. These mixing
approaches are versatile, scalable, and can be straightforwardly integrated as generic
components in a variety of lab-on-a-chip systems
On the cohomology of joins of operator algebras
Get PDFThe algebra of matrices M with entries in an abelian von Neumann algebra is a C*-module. C*-modules were originally defined and studied by Kaplansky and we outline the foundations of the theory and particular properties of M. Furthermore, we prove a structure theorem for ultraweakly closed submodules of M, using techniques from the theory of type I finite von Neumann algebras.
By analogy with the classical join in topology, the join for operator algebras A and B acting on Hilbert spaces H and K, respectively, was defined by Gilfeather and Smith. Assuming that K is finite dimensional, Gilfeather and Smith calculated the Hochschild cohomology groups of the join.
We assume that M is the algebra of matrices with entries in a maximal abelian von Neumann algebra U, A is an operator algebra acting on a Hilbert space K, and B is an ultraweakly closed subalgebra of M containing U. In this new context, we redefine the join, generalize the calculations of Gilfeather and Smith, and calculate the cohomology groups of the join
Two-parameter deformed supersymmetric oscillators with SUq1/q2 (n vertical bar m)-covariance
No full textA two-parameter deformed superoscillator system with SUq1/q2 (n/m)-covariance is presented and used to construct a two-parameter deformed N = 2 SUSY algebra. The Fock space representation of the algebra is discussed and the deformed Hamiltonian for such generalized superoscillators is obtained. Finally, some physical applications of the two parameter deformed superoscillators algebra with the quantum supergroup SUq1/q2 (n/m)-symmetry are also discussed in detail. (C) 2009 Elsevier B.V. All rights reserved
Intern experience at CH���M Hill, Inc.: an internship report
Get PDFIncludes author's vita"Submitted to the College of Engineering of Texas A&M University in partial
fulfillment of the requirement for the degree of Doctor of Engineering."Includes bibliographical referencesA review of the author's internship experience with CH���M HILL, Inc.
during the period September 1975 through May 1976 is presented. During this nine month
internship the author worked as an Engineer II in the Industrial Processes discipline of this
large consulting engineering firm... The author's prime responsibility was as one of three
lead design engineers on the design of a large wastewater treatment facility for a pulp mill
in Hoquiam, Washington owned by ITT Rayonier Inc. The work generally consisted of the design
of individual treatment units and associated piping and pumping. The purpose of the project
was to provide wastewater treatment capabilities that would satisfy the effluent limitations
(standards) imposed upon the mill by the State of Washington Department of Ecology and the
U.S. Environmental Protection Agency. The author's assignment also entailed necessary
interaction with the project manager and other CH���M HILL design engineers and support staff
members, the client's representatives, and representatives of two other consulting engineering
firms working on the project. Thus, the internship position at CH���M HILL provided considerable
experience coordinating the author's work with the work of other engineers, guiding the design
and administrative efforts of a support staff, and interacting regularly with the client and
other consulting firms. This broad exposure to a variety of engineering and organizational
problems provided a valuable educational experience
Electrohydrodynamic induction and conduction pumping of dielectric liquid film: theoretical and numerical studies
Get PDFElectrohydrodynamic (EHD) pumping of single and two-phase media is attractive
for terrestrial and outer space applications since it is non-mechanical, lightweight, and
involves no moving parts. In addition to pure pumping purposes, EHD pumps are also
used for the enhancement of heat transfer, as an increase in mass transport often
translates to an augmentation of the heat transfer. Applications, for example, include
two-phase heat exchangers, heat pipes, and capillary pumping loops.
In this research, EHD induction pumping of liquid film in annular horizontal and
vertical configurations is investigated. A non-dimensional analytical model accounting
for electric shear stress existing only at the liquid/vapor interface is developed for
attraction and repulsion pumping modes. The effects of all involved parameters
including the external load (i.e. pressure gradient) and gravitational force on the nondimensional
interfacial velocity are presented. A non-dimensional stability analysis of
EHD induction pumping of liquid film in a vertical annular configuration in the presence
of external load for repulsion mode is carried out. A general non-dimensional stability criterion is presented. Stability maps are introduced allowing classification of pump
operation as stable or unstable based on the input operating parameters.
An advanced numerical model accounting for the charges induced throughout the
bulk of the fluid due to the temperature gradient for EHD induction pumping of liquid
film in a vertical annular configuration is derived. A non-dimensional parametric study
including the effects of external load is carried out for different entrance temperature
profiles and in the presence of Joule heating.
Finally, a non-dimensional theoretical model is developed to investigate and to
understand the EHD conduction phenomenon in electrode geometries capable of
generating a net flow. It is shown that with minimal drag electrode design, the EHD
conduction phenomenon is capable of providing a net flow. The theoretical model is
further extended to study the effect of EHD conduction phenomenon for a two-phase
flow (i.e. a stratified liquid/ vapor medium). The numerical results presented confirm the
concept of liquid film net flow generation with the EHD conduction mechanism
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