Engineering Commons^™

Production Of Blanking Circles And Dies - An Appropriate Method, V Bhandari

Tanzania Journal of Engineering and Technology (TJET)

A large important blanking die for production of multiwick stoves oil tanks was damaged beyond repair during normal maintenance. A replacement die could not be made available immediately. Initially an alternative blank production system based upon the adaptation of the inhouse and locally available tools was set up. Subsequently a temporary low cost and a permanent replacement blanking die was designed, developed and manufactured out of pad welding of mild steel plate. Recommendations have been drawn in light of the experiences gained in the deployment of these appropriate methods.

Towards The Development Of A Seed Minimum Tillage Planting, G Mutoizi

Tanzania Journal of Engineering and Technology (TJET)

Some advantages of minimum tillage compared to conventional tillage. systems are given. An evaluation of current minimum tillage planters is then made identifying two major problems namely the handling of trash. which detracts from making a continuous furrow of uniform depth, and unnecessary power Consumption When making this continuous furrow in spaced planting of seeds. Then the design, manufacture and development of a rig type of a seed injector for use in precision-drilling of a typical tropical geed is presented. It is to inject the Seed using rotary sleeve Valve in which is tractor drawn. Preliminary field testing of the …

Distributive Mixing Performance Of Rubber Internal Mixers, B Mutagahywa

Tanzania Journal of Engineering and Technology (TJET)

Results of experiments to study the distributive mixing performance of Internal mixers are reported in this paper. Distributive mixing was assessed by monitoring the uniformity of sulphur distribution throughout rubber mixes subjected to a range of rotor revolutions. The results indicate that distributive mixing in a well controlled Internal mixer is rapid and unlikely to be a source of mix variability.

Trends In Metal (Pb, Zn, Ni, As And Se) Concentrations In The New Jersey Air Environment, Geoffrey Ike Ejiofor

Theses

The trend and atmospheric concentrations of five trace elements (Pb, Zn, Ni, As and Se) were studied at Newark (urban site) and Ringwood (rural site), New Jersey, during January - September 1985, whilst the Hackensack Meadowlands, New Jersey were monitored during October 1985-March 1986. The analytical procedure involved collection of the airborne particulates on a glass fiber filter using a non-dichotomous high volume sampler. The samples were digested and analyzed using the atomic absorption spectrophotometer. It was ascertained that Newark and Meadowlands exhibited higher average concentrations of Zinc and Lead than Ringwood. It was concluded all the metals originated mostly …

Parametric Excitation Of An Axially Moving Band By Periodic Edge Loading, W-Z Ben Wu, C. D. Mote

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Simple torsion parametric resonance and combination torsion-bending parametric resonance can be excited in an axially moving band by an in-plane periodic edge loading that is normal to the longitudinal axis of the band. The model simulates band saws, belts, magnetic tapes and like systems under edge forces. Sum combination instabilities, in particular, permit the excitation of low frequency resonances by higher frequency edge forces. Simple bending, combination torsion-torsion, combination bending-bending and difference type parametric instabilities are not excited by periodic normal edge forces. The space of band parameters leading to parametric instability shrinks with increasing axial tension and with increasing …

Optimal Cure Cycle Design Of A Resin-Fiber Composite Laminate, Jeenson Sheen

Mechanical & Aerospace Engineering Theses & Dissertations

High performance polymeric composites have been experiencing increasing usage in the aerospace and automobile industries. Such materials are commonly composed of long or chopped fibers embedded in the thermosetting resin matrix. Changes in physical and chemical properties of such composite materials during the cure process are rather complex. Thus, it is not a trivial task to properly design a cure cycle (temperature and pressure profiles) for a cure process. The material should be cured uniformly and completely with the lowest void content; the temperature inside the laminate must not exceed some maximum value; and the cure process should be completed …

Physical And Mechanical Properties Of A New Type Of Polymer Concrete, Kyan Bin Khoo

Theses

A new type of Polymer concrete is an admixture of a special Latex, Portland cement and Sand. It has high bond strength, quick curing, durability and adequate strength. The Mechanical and Physical properties were investigated in this paper. Reinforcement with Glassfiber was done and its properties compared to those of control specimens. The heat generation in Polymer Concrete (PC) and its relationship with the properties of PC was also investigated.

A new type of Polymer concrete is an admixture of a special Latex, Portland cement and Sand. It has high bond strength, quick curing, durability and adequate strength. The Mechanical …

Eigenvalue And Eigenvector Design Sensitivity Analysis For Nonlinear Beam Vibrations, Jian-Zhong Yuan

Mechanical & Aerospace Engineering Theses & Dissertations

A beam with immovable ends under large amplitude oscillations is axially subjected to an amplitude-dependent stretching force which is induced by the geometrical nonlinearity. The design sensitivity analysis for such a beam is investigated in this study.

Two variational formulations based on different approximations of nonlinear stretching force are studied firstly. The analytical equations of design sensitivity analysis for these nonlinear eigenproblems are then derived. Finally, a computational scheme using finite element method is developed to calculate the design sensitivity derivatives of the eigenvalue and eigenvector numerically. Numerical examples associated with the nonlinear eigenvalue and eigenvector analysis, as well as …

Vibration Coupling In Continuous Belt And Band Systems, C. D. Mote, W-Z Ben Wu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Small transverse oscillation of an endless band supported by wheels couples the response of the free spans of the band to oscillation of the wheels. The coupling arises from the finite curvature of the free spans of the band when its bending stiffness is finite. Significant modeling error can occur if a single span of the band is modeled as a simply supported, axially moving beam. The coupling provides an opportunity to dissipate vibration energy. Experiments and finite element analyses support the coupling discussion presented. © 1985 Academic Press Inc.

An Electro Hydrodynamic Study Of The Negative Corona Electric Wind, Henry Thadei Kadete

Tanzania Journal of Engineering and Technology (TJET)

The velocity of corona generated electric wind is measured. From the velocity profile mass movement and electrokinetic conversion efficiencies are deduced. High speed schlieren photographs illustrate the form of the velocity distribution function as well as its high degree of turbulence.

The Quantitative Analysis Of Airborne Particulates By X-Ray Flourescence, George C. Asteriou

Theses

Airborne particulate matter from the New Jersey State area collected on Quartz Microfiber filters was analyzed by X-Ray Fluorescence spectroscopy. The quantitative analysis of the samples against N. B. S. standards produced results which were compared with Atomic Absorption analysis

The results from the two methods were correlated by the introduction of empirical factors for each element.

However, a larger number of analyzed standards of varied composition, along with the creation of a spectral library, can minimize the need for empirical factors and yield accu¬rate results.

Structural Self-Shadowing And Its Effects On The Thermal-Structural Behavior Of Orbiting Trusses, Jack Mahaney

Mechanical & Aerospace Engineering Theses & Dissertations

The determination of structural shadowing is described. The computation of environmental heat loads for slender structural members in earth orbit is described, and two methods for finite element thermal analysis are described . The effects of self-shadowing on the thermal structural behavior of single truss members and two different trusses are presented. In each case the shadowing produces a noticeable effect on the temperature distributions on truss members, and on the deformations of the trusses.

Analysis And Optimal Design Of Wind Tunnel Balances, Sung-Ling Twu

Mechanical & Aerospace Engineering Theses & Dissertations

The problem of finding the optimal cross-sectional shape of the elastic cage in wind tunnel balance is formulated and solved numerically. A mathematical model to implement the boundary condition associated with the elastic rigid connection into the finite element method is discussed. Numerical results show that the rigid connection at the end of the elastic cage has significant effect on the stress distribution.

The finite dimensional approach for a three dimensional design sensitivity analysis is derived. Using both the free and rigid boundary conditions, numerical examples are performed and comparisons of the accuracy of design sensitivity analysis between the proposed …

Microcomputer Based Digital Image Processing System Developed To Count And Size Laser-Generated Small Particle Images, K. D. Ahlers, D. R. Alexander

Department of Mechanical and Materials Engineering: Faculty Publications

A microcomputer-based digital image processing system has been developed to count and size laser-generated small particle images. Processing rates of 5 to 600 frames per minute were achieved by utilizing a real-time digital image processor. Particles from 7 to 700 µm in the plane of focus were counted and sized. A major emphasis in this work was to determine the basic problems and limitations involved with using a digital image processing scheme to accurately size particles. Areas that were investigated include the effect of the threshold level on measured particle size, particle boundary diffraction gray-level gradients, and geometric nonlinearities introduced …

Negative Corona Current Characteristics Of An Electric Wind System, Aviti Kadete

Tanzania Journal of Engineering and Technology (TJET)

The corona current characteristics of an electric wind system are investigated. First a brief summary of the negative point to plate corona mechanism and characteristics are presented. Then empirical equations for corona currents of an electric wind system are derived. Current waveform characteristics are also discussed. The effects of placing parallel rods in between a point-plate electrode gap to the corona currents are highlighted.

The Eccentric Disc Pitter Planter-A Soil Conservation Tillage Tool For Mechanized Farming., J Dumelow

Tanzania Journal of Engineering and Technology (TJET)

A planting technique which could enhance agricultural production is presented. The Edip planting technique which is discussed has low capital and operating costs. It also has reasonable and reliable yields as well as providing effective moisture and soil conservation.

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 …