Engineering Commons^™

Hydraulic Rams For Rural Water Supply Schemes In Selected Areas In Tanzania, T Mbwette

Tanzania Journal of Engineering and Technology (TJET)

This paper presents one of the many efforts made by the Faculty of Engineering and the Institute of Production Innovation of the University of Dar es Salaam towards the realization of the International Water Supply and Sanitation Decade. Special reference is made to the use of hydraulic rams along with some simple water treatment methods. Besides the account of theoretical and practical work done to-date in the field of water supply, a further evaluation of the theoretical model presented is recommended so as to enable a judgement of the present hydraulic ram designs to be done. Tests on a typical …

Synthesis Of Trimethylpropane-Tolylene-2,4-Diisocyanate Adduct And Its Blocked Monomers, Farhad Forohar

Theses

A trimethylolpropane adduct of tolylene-2,4-diisocyanate (TMP-TDI) was prepared by reaction in a heterogeneous solvent system. The isocyanate functional groups of the TMP-TDI adduct were blocked with the following blocking agents: p-cresol, eugenol, o-chlorophenol, and one to one mole ratio of mixtures of 2-hydroxyethyl methacrylate (HEMA) and each of the three preceding blocking agents. A sample of TMP-TDI adduct blocked with only HEMA was also prepared. The products were characterized by melting point, infrared spectroscopy, and elemental analysis. Monomers of TMP-TDI blocked with 50% HEMA and 50% blocking agents may be very useful as dental restorative materials.

An Experimental And Analytical Investigation Of The Iosipescu Shear Test For Composite Materials, Barry Stuart Spigel

Mechanical & Aerospace Engineering Theses & Dissertations

Mechanical properties of composite materials under shear loading are difficult to determine. The Iosipescu Shear test, originally proposed for metals, has in recent years been applied to composites. It has the advantages of small specimen size, simple loading and a reasonably uniform shear stress in the test section.

The purpose of this work is to study the validity of the Iosipescu test method for measuring the shear modulus and shear strength of composites. Finite element analyses indicate that optimum specimen geometry and load locations depend upon the degree of orthotropy of the composite. Test results for a quasi-isotropic graphite/epoxy laminate …

Three Studies On Airborne Polycyclic Aromatic Hydrocarbons, Carol Sophia Eveleens

Theses

Three studies have been conducted on polycyclic aromatic hydrocarbons found on airborne particulate matter. The first investigation involves the determination of fly ash "activity" in the reaction of two PAHs adsorbed on its surface. Mass spectrometry is used to monitor the exchange of hydrogen and deuterium atoms between anthracene and anthracene-d10. The results indicate that some fly ashes exhibit "activity" in the reactions of PAHs adsorbed on its surface. The second investigation involves the determination of cyclopenta[cd]pyrene (CcdP) and benzo[ghi]flouranthene (BghiF) on samples of airborne particulate material collected from two automobile traffic tunnels. Glass capillary gas chromatography with a precolumn …

Calibration Of Flame Ionization Detector For Chlorinated Hydrocarbons, Nahid Jabalameli

Theses

Relative Responses and Calibration Factors were developed for several volatile organic (mostly chlorinated) priority pollutant species in order to use one single stable compound (e.g.Benzene) for daily instrument calibration. This would replace the procedure of using a standard mixture of target compounds (25-35). This is of particular advantage because the standard mixture may not have all species stable or may show loss of some components relative to others due to wall adsorption in the standard (compressed gas) stainless steel cylinder.

The use of a single standard species was made possible by developing "accurate" relative response and calibration factors of all …

Characterization Of Tdi-Hema Homopolymer Prepared Via An Immiscible Solvent System. Synthesis And Investigation Of Oligodichloroketene, Manuel Montero

Theses

The objective of this thesis has been divided in two parts.

The first part is subdivided into two areas. First a "Universal" calibration curve for gel permeation chromatography (GPC) was construc-ted using different molecular weight standards of PMMA and MMA-HEMA co-polymers. By measuring the viscosity of the different molecular weight solutions and calculating the Vr, (retention volume), from GPC data, plots of In [ η ] Mw against Vr and In Mw against Vr are obtained. These curves can be used to obtain the molecular weight of any linear (not crosslinked) copolymer by simple measurements of viscosity and GPC data. …

Shape Optimization For Elastic Hollow Bars In Torsion, Jahau Lewis Chen

Mechanical & Aerospace Engineering Theses & Dissertations

The problem of finding optimal cross-sectional shapes of elastic hollow bars in torsion is formulated and solved numerically. A variational formulation for the state equation is presented, and the material derivative of continuum mechanics is used for the shape design sensitivity analysis. Performance criteria include the bending stiffness, the torsional rigidity, and the weight of the bar. The existence of a keyway, an example of geometric irregularity, can be considered as well. The material can be either isotropic or anisotropic. The finite element method is used for the numerical solution of the variational state equation and is integrated into an …

Finite Element Thermal-Structural Analysis Of Cable-Stiffened Space Structures, Ajay Kumar Pandey

Mechanical & Aerospace Engineering Theses & Dissertations

Finite element thermal-structural analyses of cable-stiffened space structures are presented. A computational scheme for calculation of prestresses in the cable-stiffened structures is also described. The determination of thermal loads on orbiting space structures due to environmental heating is described briefly. Three finite element structural analysis techniques are presented for the analysis of prestressed structures. Linear, stress stiffening and large displacement analysis techniques are investigated.

The three techniques are employed for structural analysis of prestressed cable structures at different prestress levels. The three analyses produce similar results at small prestress. but at higher prestress differences between the results become significant. For …

Design Of A Combustion System Simulating Waste Heat Recovery From Diesel Engine Exhaust Gases, Nikolaos Papadopoulos

Mechanical & Aerospace Engineering Theses & Dissertations

A forced-draft laboratory combustion system simulating diesel engine exhaust gas volume flow rate and temperature conditions for waste energy recovery is analyzed and discussed. The system consists of a fan which supplies the air. The slightly compressed air is then ducted through a combustor where it is heated, and then to an air-quencher where it is cooled to a desired temperature. Finally, the air is sent through a heat exchanger, after a diffuser process, for waste heat recovery.

A gas dynamic analysis has been performed for each component part as well as a parametric study via a computer program in …

Preparation And Characterization Of Blocked Diisocyanate Monomers For Dental Applications, Stephen Richard Angeli

Theses

Six new monomers were prepared and characterized. The six monomers are blocked diisocyanate compounds. In the preparation 2,4-tolylene diisocyanate was first blocked with 2=hydroxyethyl methacrylate in the para NCO position. Six different blocking agents were then used to block the ortho NCO in the preparation of the monomers: (1) p-methoxyphenol, (2) m-methoxyphenol, (3) o-methoxyphenol, (4) p-chlorophenol, (5) m-chlorophenol, and (6) o-chlorophenol. The six monomers were characterized by mp, liquid chromatography, IR, NMR, and elemental analysis. All the characterizations show that the monomers are indeed the desired products.

Preparation And Characterization Of Blocked Isocyanate Monomer Polymer And Equilibrium Constant Of Deblocking, Kirti P. Kamdar

Theses

A 2-Hydroxyethyl methacrylate (HEMA) adduct of toluene 2-4 diisocyanate (TDI) was prepared in petroleum ether at 35-40°C under nitrogen. In order to prepare the monomer, equimolar amounts of TDI and HEMA were reacted with P-cresol which functions as a blocking agent.,Di-butyltin dilaurate was used as a catalyst and chloranil was used as an inhibitor. The solid monomer which was obtained was recrystallized, and polymerized in chloroform using azobis isobutyronitrile as initiator.

Monomer and polymer were characterized using infrared spectroscopy, melting point, liquid chromatography gel permeation chromatography. A vapor pressure osmometric study of the polymer in three different solvents at three …

Domestic Water Heating With Microwave Radiation, Dan Lynn Merchant

Graduate Research Papers

Purpose of the Study

1. To determine if microwave radiation can be safely employed in a domestic water heating system.

2. To determine if microwave radiation can be efficiently and economically employed in a domestic water heating system.

3. To determine if microwave radiation can be effectively employed in a domestic water heating system.

The Use Of Complex Versus Normal Modes In Structural Model Improvement, Chih Lin

Mechanical & Aerospace Engineering Theses & Dissertations

In the past, normal modes approximation to complex modes was employed by most researchers or users in the process of identification or modification of structural systems. This is true, of course for simple structures with no or proportional damping. For complex structures with nonproportional damping, even level of which is small, it will be shown that applying this approximation is inadequate. Use of complex modes instead of approximated normal modes is justified.

An algorithm is presented that computes a set of normal modes from the corresponding measured complex modes. The computed normal modes are then used in the Berman's technique …

The Quantitative Determination Of The Elemental Composition Of Coal Fly Ash Samples Using X-Ray Fluorescence, Joseph R. Cervassi

Theses

Bulk constituent elements contained in coal fly ash were measured by X-ray fluorescence spectroscopy in eight samples. Four samples were used as calibration standards for the spectrometer since their compositions were previously determined by atomic absorption spectrometry. Calibration coefficients of the standards were calculated with computer assisted regression analysis of the fluorescence spectra, and used to determine the composition of the remaining four samples. The compositions of the latter four samples, as predicted by X-ray fluorescence, were then compared to atomic absorption results. X-ray fluorescence and atomic absorption results agree best when the concentrations of elements in the standards are …

Preparation Of Aniline-Formaldehyde Ion-Exchanger Fiber : Part I : Polymer Synthesis And Fiber Curing, Ching-Hsin Chen

Theses

Aniline-Formaldehyde polymer was synthesized by a new procedure ( as opposed to the conventional approach ). With an equal molar ratio of aniline and formaldehyde and a small amount of oxalic acid, the resulted polymer is free from gels and is suitable for fiber transformation.

The polymer is a transparent yellowish resin, having a melting range between 100-115C, and an average molecular weight 1200. The polymer was intended to be the precursor material for ion-exchange fibers. However, due to the time limit, this thesis only covers the work of polymer synthesis, fiber spinning and the identification of an crosslinker.

Among …

Large Amplitude Free Flexural Vibrations Of Laminated Composite Plates Of Arbitrary Shape, Mo-How Shen

Mechanical & Aerospace Engineering Theses & Dissertations

A finite element formulation is presented for analyzing large amplitude free flexural vibrations of symmetrically laminated composite plates of arbitrary shape. Linear and nonlinear fundamental frequencies are determined from the analysis. The laminates are made of multiple generally or specially orthotropic layers and symmetrically disposed about the middle surface, hence there is no coupling between bending and extension. Linearized stiffness equations of motion governing large amplitude oscillations of laminates, linear element stiffness matrix, quasi-linear geometrical element stiffness matrix, and solution procedures are presented. The linearized geometrical stiffness matrix for a 18 degrees-of-freedom high precision triangular anisotropic plate element is evaluated …

Application Of Least-Squares Method To The Determination Of Orthotropic Elastic And Photoelastic Constants, R. G. Chermahini

Mechanical & Aerospace Engineering Theses & Dissertations

A least-squares technique is developed in matrix form to determine orthotropic elastic and photoelastic constants. Orthotropic elastic constants are determined by mounting strain gages on a half-plane specimen which is subjected to a compressive concentrated force. Strain values corresponding to a 1000 lb load and coordinates of the points where the gages are located are used as input data to the governing equation of orthotropic elasticity for the model under consideration. Orthotropic photoelastic constants are determined using a transparent composite half-plane model which is subjected to a concentrated load. Photoelastic constants are determined using the coordinates of selected point on …

Development Of A Friction Element For Metal Forming Analysis, W. D. Webster, Robert L. Davis

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A three-dimensional finite element friction element has been developed. The friction element has been used in the analysis of round-to-square forward extrusion.Comparison with some limited experimental data is presented. © 1982 by ASME.

A Mathematical Model Used In Conjunction With A Finite Element Analysis To Aid In The Design And Analysis Of Bourdon Tubes, R. C. Weber, Robert L. Davis

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A mathematical model that describes a variety of Bourdon tube geometries has been used for the three-dimensional analysis of Bourdon tubes. The variation of the stresses and tip deflections with respect to the variables used in the mathematical model are then presented as an aid in the design and analysis of the Bourdon tube. The finite element program represents a user-orientated package for calculation of tip deflections and stresses. Stresses and deflections are compared to both strain gage data and instrumented tip deflections as well as published data to establish the credibility of both the model and computer program. © …

Photoelastic Investigation Of Load Transfer In Eccentrically Loaded Single Lap Joints, Stephen Antrim Hann

Mechanical & Aerospace Engineering Theses & Dissertations

Photoelastic models of three eccentrically loaded single lap joints were analyzed. The adherends of each joint were identical and the bondlines differed in thickness and material properties. The adherends were analyzed for both cylindrical plate behavior and geometrical nonlinearity and the load transfer efficiency was examined. For all three models it was found that over 98% of the shank behaves as a cylindrical plate and that a geometrically nonlinear analysis yields bending stresses substantially lower than a linear analysis and that a relatively thick, low modulus bondline can increase load transfer efficiency.

A Purely Chemical Nitrogen Dioxide Laser, Conrado Mendoza Malalis

Theses

Purely chemical lasers promise to provide future high-power lasers for remote installations, airplanes, ships and in space without the necessity of external electric power, sources.

This study is about the design and construction of a new, gas phase purely chemical NO₂ laser, based on the reaction of NO + O₃ + NO≠₂ + O₂. The vibrationally excited NO≠₂ species at 1-40 mm Hg total pressure is the source of energy (photons) for the laser. A series of computer program calculations on the reaction kinetics and relaxational processes involved have also been made, …

Low Speed Handling Characteristics Of A Supersonic Transport By Eigenstructure Assignment, Michael Peter Lazar

Mechanical & Aerospace Engineering Theses & Dissertations

A synthesis procedure, based upon optimal regulator theory and eigenvalue/eigenvector assignment technique, was used in the design of a low-speed lateral control system for the SCAT-15F supersonic transport. Emphasis was placed on reducing the lateral acceleration at the pilot's station. Control laws were designed to make the aircraft handling characteristics acceptable with the exception of the lateral acceleration. It was found that a compromise between the roll performance requirements and the peak lateral acceleration requirement is needed for a successful SCAT-15F design.

Goertler Instability In Compressible Boundary Layers Along Curved Surfaces With Suction And Cooling, Alok K. Verma

Mechanical & Aerospace Engineering Theses & Dissertations

The Goertler instability of the laminar compressible boundary layer flows along concave surfaces is investigated. The linearized disturbance equations for the three-dimensional, counter-rotating streamwise vortices in two dimensional boundary layers are presented in an orthogonal curvilinear coordinates. The basic approximation of the disturbance equations, that includes the effect of the growth of the boundary layer, is considered and solved numerically. The effect of compressibility on critical stability limits, growth rates, and amplitude ratios of the vortices is evaluated for a range of Mach numbers for Oto 5. The effect of wall cooling and suction of the boundary layer on the …

An Apparatus For Measuring The Thermal Conductivity Of Cast Insulation Materials, Christine A. Wilkins, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

A steady-state apparatus has been developed for measuring the thermal conductivity of cast materials. The design has employed a novel thermal symmetry arrangement which can permit total electrical isolation of the test material from its surroundings. © 1980 American Institute of Physics

The Significance Of Peel Stresses In Cyclic Debonding, Richard A. Everett Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

One of the possible failure modes in adhesively bonded joints is cyclic debonding -- progressive separation of the adherends by cyclic failure of the adhesive bond. In this study cyclic debonding in an adhesively bonded crack-lap shear specimen has been investigated by means of a linear elastic finite-element analysis and a series of constant­ amplitude axial fatigue tests. The primary purpose of this study was to test the hypothesis that cyclic debonding is due largely to tensile peel stresses in the adhesive.

The results of this study have indicated that not all of the tensile peel stresses in the adhesive …

Non-Linear Behavior Of Unbraced Two-Bay Reinforced Concrete Frames, Mehdi Shadyab

Dissertations and Theses

In this investigation, the primary objective was to study the nonlinear behavior of unbraced two-bay concrete frames and to determine the extent to which ultimate load theory or limit design can be applied to these structures. The frame behavior was investigated analytically by two methods. In the first method the frame stability equation was derived assuming that members of the frame possess an elasto-plastic moment-curvature relationship. This stability analysis was also carried out by another model consisting of a column attached to a linear spring and carrying the total frame load. The second method was through a computer program which …

The Efficiency Of A Two-Edged Tool And Its Improvement, J. R. Masuha

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Steel Making In Port Talbot Works Of British Steel Corporation, S. P. Mosha

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Split-Set Rock Bolt Analysis, Robert L. Davis

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A system of twelve equations have been developed for the elastic-plastic analysis of split-set roof bolts and these equations have been programmed for solution on the IBM 370/168 computer. Typical solutions have been presented in graphical form for comparison with experimental data. The results compare favorably for most of the split-sets providing the system parameters are properly specified. It appears that this analytical solution will be valuable to mining engineers since the solutions have been put in graphical form. Plots of the effects of the various parameters (material strength, material strain-hardening, friction, thickness, radius, angle of contact) on the holding …

Studies Of Fracture And Deformed Surfaces Of High Strength Aluminum Alloys By X-Ray Diffraction, Tamma K. Kumar

Mechanical & Aerospace Engineering Theses & Dissertations

X-ray observations of fatigue fracture and deformed surfaces of 7075-T6 aluminum were conducted in this study. The (111) and (222) diffraction peaks were obtained from the fractured and deformed surfaces. It was observed that in comparison with the base metal, the fracture exhibited line broadening similar to that due to cold working. The broadening is indicative of plastic deformation in the vicinity of the advancing crack tip during the fracture process. Also the different regions of fracture exhibited varying degrees of line broadening. With respect to the fatigue crack, the slow crack growth region showed a greater broadening, and, hence, …