Engineering Commons^™

Effective Thermal Conductivity Estimates Of Particulate Mixtures, Christiaan Richter, Hendrik J. Viljoen, N.F.J Van Rensburg

Papers in Physical Properties

Several theories have been advanced to estimate effective thermal conductivities of particulate mixtures, but most theories have focused on the dilute case. A method is proposed to estimate the effective thermal conductivity coefficient of mixtures of arbitrary concentration. Earlier the authors developed a theory to determine the expected contact area between different species. This theory is employed to determine the Kapitza resistance of the heterogeneous mixture and forms part of an overall theory to estimate the effective thermal conductivity. Results are compared with other theoretical estimates and with experiments.

Microbial Cellulose Utilization: Fundamentals And Biotechnology, Lee R. Lynd, Paul J. Weimer, Willem H. Van Zyl, Isak S. Pretorius

Dartmouth Scholarship

Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial …

Extraction Of Silymarin Compounds From Milk Thistle (Silybum Marianum) Seed Using Hot, Liquid Water As The Solvent, J.F. Alvarez Barreto

Inquiry: The University of Arkansas Undergraduate Research Journal

High value specialty chemicals are usually obtained from natural products by extracting with generally regarded as safe (GRAS) solvents. Because organic solvents are quite often used, high operating and disposal costs often occur. When compared to traditional solvents, water can be viewed as an interesting alternative because of its low operating and disposal costs. Milk thistle contains compounds (taxifolin, silychristin, silydianin, silybinin A and silybinin B) that display hepatoxic protection properties. This paper examines the batch extraction of silymarin compounds from milk thistle seed meal in 50'C, 70'C, 85'C and 100'C water as a function of time. For taxifolin, silychristin, …

Modeling Adsorption Of Cane Sugar Colorant In Packed-Bed Ion Exchangers, Hugh Anthony Broadhurst

LSU Master's Theses

The removal of cane sugar solution colorant by packed-bed ion exchangers was modeled using a linear driving force (LDF) adsorption model. Adsorption of colorant is of interest to the developers of the White Sugar Mill (WSM) process as it is a complex subject. The problem is that color is an indiscrete mixture of many components making it difficult to measure and even more challenging to model. Colorant formation was investigated using gel permeation chromatography (GPC) with the objective of developing a method to define pseudo-components representative of cane sugar solution colorants. WSM is a process for producing white sugar directly …

Institutional And Other Constraints To Non-Oil Exports., R. O. Madaki

Bullion

This paper examines the non-oil exports sector in Nigeria which had witnessed a lacklustre performance despite the several statements of government's interest in export-biased growth strategy and the establishment of several export facilitating institutions. The paper further observes that a major problem with Nigeria's non-oil export sector is that it is not predicated on the design and implementation of appropriate and coherent economic policies as there is no clear export promotion blue print in Nigeria. Consequently, the sector is facing a number of institutional and other domestic and external problems. The remaining part of the paper briefly highlight some of …

Nanofiltration-Based Diafiltration Process For Solvent Exchange In Pharmaceutical Manufacturing, Jignesh P. Sheth

Theses

Commercially available solvent stable polymeric nanofiltration membranes were used to study the nanofiltration and diafiltration operations in the context of the pharmaceutical industry. Experimental results are presented for a two-step operation involving the preconcentration of a feed solution via nanofiltration followed by the replacement of the first stage solvent with a second solvent via diafiltration in two stages. Membranes MPF-50 and MPF-60, having molecular weight cut-offs of 700 and 400 respectively, were used in the present study. A solution of erythromycin (MW 734) in ethyl acetate was preconcentrated via nanofiltration followed by replacement of ethyl acetate with methanol via batch …

Apparatus And Method For The Generation And Use Of Ferric Ions, Donald R. Lueking, Carl C. Nesbitt

Michigan Tech Patents

An apparatus and method for the generation and use of ferric ions produced by acidophilic, chemoautotrophic bacteria.

Modeling Of Solid Phase Detonations, C. Richter, Hendrik J. Viljoen, N. F. J. Van Rensburg

Papers in Reaction Kinetics

In contrast to conventional explosives which constitute rapid decomposition of the molecular structure acconlpanied by the release of large volumes of gaseous products, heterogeneous mixtures in the SHS realm react by progression of a thermal wave at velocities far below the speed of sound in such mixtures. Interestingly, ultrafast solid phase reactions can be initiated under the right conditions. A shock wave compresses the solid mixture to densities well beyond the theoretical mean ambient density (TMD) and compression becomes the major form of preheating. In addition, elastic potential energy is pumped into the lattice structure to induce severe distortion and …

Predicting The Unconfined Compressive Strength Of The Breathitt Shale Using Slake Durability, Shore Hardness And Rock Structural Properties, Engin C. Koncagül, Paul M. Santi

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Compressive strength is the most widely used design parameter in the construction industry and in rock engineering. For example, Bieniawski [Bieniawski, Z.T., Estimating the strength of rock materials, Is. J. S. Afr. Inst. Min. Metall., 1974, 74, 312-320.] reported that mining engineers request the uniaxial compressive strength (UCS) more often than any other rock property. However, standards set for specimen preparation are very demanding. Therefore, it is quite difficult and sometimes impossible to fulfill these requirements using weak rocks and especially shales. This paper evaluates the use of the slake durability and Shore hardness tests to estimate UCS, based on …

Magma Traps And Driving Pressure: Consequences For Pluton Shape And Emplacement In An Extensional Regime, John Patrick Hogan, Jonathan D. Price, M. Charles Gilbert

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The level of emplacement and final form of felsic and mafic igneous rocks of the Wichita Mountains Igneous Province, southwestern Oklahoma, U.S.A. Are discussed in light of magma driving pressure, lithostatic load, and crustal magma traps. Deposition of voluminous A-type rhyolites upon an eroded gabbroic substrate formed a subhorizontal strength anisotropy that acted as a crustal magma trap for subsequent rising felsic and mafic magma. Intruded along this crustal magma trap are the A-type sheet granites (length/thickness 100:1) of the Wichita Granite Group, of which the Mount Scott Granite sheet is typical, and smaller plutons of biotite bearing Roosevelt Gabbro. …

Optical Digital Fragmentation Measuring Systems -- Inherent Sources Of Error, Norbert H. Maerz, Wei Zhou

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Automated optical imaging systems of measuring fragmentation are increasingly being used in the mining, comminution, and materials handling industries. These methods have been well received in many of the industries involved. Considering that in many of these applications there are no alternative ways of sizing material, having even a rudimentary measurement of size distributions allows evaluations of explosive, blast design, detonator performance, crusher and milling performance, and material degradation due to transport.

Optical methods have inherent limitations, which reflect on accuracy, precision, and reproducibility of measurement results. This stems from the fact that there are myriads of variables, which affect …

Methods For Predicting Shale Durability In The Field, Paul Michael Santi, Jerry D. Higgins

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Durability of shales and other weak rock is an important parameter describing the material's susceptibility to breakdown upon exposure to water or during construction work. While laboratory methods have been developed to measure durability, no correlations between laboratory results and simple field tests have been determined. The results of this study show that certain field parameters can predict slake durability with acceptable accuracy. The recommended field tests, in order of desirability, are slake index, jar slake, hammer rebound, and NGI "Q" value. Single variable and multiple variable linear regression equations are given, including equations conservatively modified so that 95% of …

Experimental And Theoretical Study Of Vibrations Of A Cantilevered Beam Using A Zno Piezoelectric Sensor, B. R. Jooste, Hendrik J. Viljoen, S. L. Rohde, N. F. J. Van Rensburg

Hendrik J. Viljoen Publications

Piezoelectric sensors can measure vibrations of solid structures very accurately. A model of a cantilevered beam, with a ZnO film on one side is presented. Both viscous and internal damping are considered. The output of the sensor is modeled and matched with experimental results by adjusting the damping parameters. A theoretical formulation for damage is introduced. Experimental results for a damaged beam confirm the shift in frequencies to lower values. The model is used to identify the extent of the damage.

Experimental And Theoretical Study Of Vibrations Of A Cantilevered Beam Using A Zno Piezoelectric Sensor, B. R. Jooste, Hendrik J. Viljoen, S. L. Rohde, N. F. J. Van Rensburg

Hendrik J. Viljoen Publications

Piezoelectric sensors can measure vibrations of solid structures very accurately. A model of a cantilevered beam, with a ZnO film on one side is presented. Both viscous and internal damping are considered. The output of the sensor is modeled and matched with experimental results by adjusting the damping parameters. A theoretical formulation for damage is introduced. Experimental results for a damaged beam confirm the shift in frequencies to lower values. The model is used to identify the extent of the damage.

Electrochemical Behavior Of Graphite And Ni-Cr Electrodes In Sodium Polysulfide In The Absence And Presence Of Hydrogen Sulfide, Z. Mao, Ralph E. White, B. Dandapani, A. Anani, S. Srinivasan, A. J. Appleby

Faculty Publications

The electrochemical behavior of graphite and Ni-Cr electrodes in sodium tetrasulfide melt has been investigated using voltammetric, chronoamperometric, and chronopotentiometric techniques in the presence and absence of hydrogen sulfide. Two continuous phases, namely, Na₂S₂ and Na₂S, are apparently formed at different potentials during the cathodic polarization. The blocking effect by these layers was much less significant on the Ni-Cr electrode than on graphite. The presence of H₂S did not appear to influence the electrode reactions, but it significantly reduced the rate of formation of the continuous phases (Na₂S₂ or Na …

Convective Regimes In Reactive Fluid Media Due To The Interaction With Catalytic Surfaces, Hendrik J. Viljoen, Jorge E. Gatica, Vladimir Hlavacek

Papers in Reaction Kinetics

Reactive fluid media enclosed in a cavity with a catalytic surface are analyzed. Nonisothermal chemical reactions on this surface can lead to convective instabilities. A simplified model is developed by using a low-order truncation of a Fourier-type expansion and employing the Galerkin method. A linear stability analysis is presented and it is shown that, under certain conditions, the marginal curve for the onset of oscillatory instabilities can lie below that for monotonic ones. The stability of the convective modes is studied by nonlinear stability analysis and it is shown how they can evolve into periodic and nonperiodic motion patterns. Numerical …

Water Desalination Using Nocturnal Radiation Cooling, Ali Mufarreh Saleh Al-Amri

Masters Theses

"In this investigation nocturnal radiation condensation cooling is considered to determine the possibility of using this method as a desalination process in remote areas, villages and resorts, etc. An experimental study was made and programs were developed to calculate water collection under ideal conditions. Both experimental and theoretical work indicated that this process is useful for small scale water production where there is no available energy sources. It can be used also in conjunction with solar desalination processes. Cost analysis and a preliminary design are included"--Abstract, page ii.

Simplifying Lubricants For Farm Machinery, R A. Platt

Journal of the Department of Agriculture, Western Australia, Series 4

All moving parts on machinery needs lubrication. With the rapid development in farm machinery and its attendant sophistifications, the stresses imposed on the lubricants have also increased.

This article looks at some of the changes in requirements and developments in lubricants available.

The Energy Needs Of The Developing Countries, Vaman Rao

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

The energy needs of the developing countries are enormous. They will grow with the passage of time as the pace of economic development accelerates and those countries enter the industrial epoch. The sheer physical non-availability of coal and petroleum to most of them makes it obligatory to choose an unconventional resource as an energy-base. The nuclear fission is the only option now available which is feasible, less-expensive and plentiful. Solar and fusion may be the ultimate sources in the steady state, when appropriate technologies are developed.

The Environmental Effects And Ecohomic Costs Of Solid Waste Energy Recovery, John P. Collins

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

Environmental and economic impacts of solid waste energy recovery systems are discussed. Emphasis is given to the Navy Salvage Fuel Boiler facility in Norfolk, Virginia. Built in 1967, it is the first waterwall steam generating facility to use solid waste as a fuel in the United States. Nine years of operational data reflect national trends in energy recovery costs and environmental problems. Steam generation costs, environmental compliance costs and facility environmental impacts are discussed.

Post World War Ii Crude Oil Prices: Collusive Or Competitive Pricing, Kern O. Kymn, Walter P. Page

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

The study presents a crude oil market model explaining the trend in crude oil prices, 1945-1976. The competitiveness of the market is assessed in terms of this model.

Coal Chemistry: Aspects Of Analysis, Structure, Reactions, Conversion, And Byproducts, Stanley E. Manahan

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

An understanding of the chemistry of coal is essential for the most efficient and environmentally acceptable utilization of this important energy resource.. This is particularly true where coal conversion processes are involved. Far from being a simple carbonaceous rock, coal is a complex and variable chemical system. This paper outlines the basic principles of coal chemistry which can be helpful to geologists, engineers, chemists, and others involved with the utilization of coal.

The Demand And Supply Of World Petroleum And Its Consequences For Agricultural Economic Development, Amalia Vellianitis-Fidas

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

The concerns related to the increase cost of petroleum in 1974 and 1975 centered around the enormous transfer of funds needed to pay for petroleum imports by most countries. Although this transfer is successfully taking place in the developed countries, it is taking place with serious long run external financial consequences for the less developed countries. In addition, these countries' continued agricultural development will probably depend on finding new paths to agricultural efficiency that are not as dependent on high-priced fuels.

The Status Of And Need For New Coal Gasification Technology, Jimmie R. Bowden

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

Movement toward a domestic coal-based energy policy has been barely perceptible since the Arab oil embargo of 1973-4. Rapidly declining supplies of natural gas for small businesses and residential uses can be supplemented by coal gasification or replacement of gas by coal as a power generating fuel. At this time it probably is the better choice to use coal to generate power instead of gas. Second generation coal gasification processes under development with ERDA financial help will not change this balance in the next 10 years if at all.

Training Programs For Energy Management In Developing Countries, J. Byron Nelson, Burns E. Hegler, J. Derald Morgan

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

This paper discusses some of the general inter-related energy, management, and economic problems in developing countries as well as a common project methodology that can be used to formulate and implement development strategies according to the needs of any particular country. Because the development of human resources, especially managerial skills, is critically needed, the characteristics of managers in developing countries, the problems they face, and their training needs are discussed. Finally an example of a specific training program is outlined.

World Oil Supplies And The Next 25 Years, J. A. Eyer

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

Petroleum must become a more efficiently used commodity while alternative energy sources are developed, but it will remain in high demand as long as the world wide availability is assured, regardless of the influence of the O.P.E.C. nations. The availability of petroleum on a country-by-country survey shows clearly that there are large known recoverable reserves as well as large potential for discovering added reserves. However, the highly industrialized nations do not have adequate petroleum supplies and this will probably not change as long as petroleum remains as the primary energy source.

An Engineering, Geological And Hydrological Environmental Assessment Of A 250 Mmscfd Dry Ash Lurgi Coal Gasification Facility, Mason H. Somerville, James L. Elder, Stephen R. Moran

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

A preliminary engineering, geological, and hydrological environmental assessment of a proposed 250 MMSCFD dry ash Lurgi coal gasification facility is discussed.

The facility's emission spectrum is examined on the basis of the proposed design and empirical data. This system utilizes approximately 13 million tons of lignite and 17,000 acre feet of water per year and consumes 6500 tons of oxygen per day. The results of the study indicate that the major gaseous effluent is CO₂, that the federal limits on SO₂ effluent may be met, and that the atmospheric degradation criterion will be the most difficult one …

The Energy Problem -- Crude Oil, J. A. Marshall

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

This paper discusses the national energy problem as it affects the demand for and availability of crude oil. Forecasts of energy demands to 1990 have been made based on population trends and changing life styles in the USA. Projections of energy supplies show a rapidly increasing gap between supply of crude oil and demand for crude oil from the early 1970's through 1990. The need for imported crude oil to supply the forecast deficit is discussed. The political and economic implications of these imports are also discussed. The need for refineries, port facilities, tankers, and pipelines are presented. Finally, recommendations …

Separation Of Glucose - Fructose - Water Systems Via Thermal Parametric Pumping, Zikri Mostafa Ahmed

Theses

Series of experiments were carried out to determine the effect of different factors on adsorption from aqueous solutions of sugar using fuller's earth ( LW 16-30 Mesh ) as an adsorbent. The equilibrium data were fitted to the Langmuir's equation., and an explanation for the deviation of some of these data has been given.

Systems of glucose-fructose and water mixtures were subjected to semi-continuous and continuous parametric pumping operations using activated carbon (400 Filterasorb) as an adsorbent. The results obtained confirm the equilibrium theory of the parametric pump and essentially fulfill the requirements established by Chen and Hill (6) to …

Commentary On And Extension Of Calculative Procedure For Co2 Production, Ralph M. Rotty

Mechanical & Aerospace Engineering Faculty Publications

Further refinements are made in the method of calculating amounts of carbon dioxide released to the atmosphere through the combustion of fossil fuels. Data available in the UN Statistical Yearbook are used as the basic sources rather than the summary, World Energy Supplies, U.N. Statistical Papers, Series J because the most recent data are available several months earlier in the yearbook and because data are included for natural gasoline, natural gas liquids, and cement production. Coal, lignite, crude petroleum, “marketed” natural gas, flared natural gas, and cement are itemized separately and revised CO₂ emission estimates are made for …