Engineering Commons^™

Some Aspects Of Erosive Waves At Kunduchi Beach, Dar Es Salaam, Tanzania, Alfonse Dubi

Tanzania Journal of Engineering and Technology (TJET)

The area north of the Dar es Salaam City is endowed with beautiful sandy beaches and high concentration or tourist beach hotels that are threatened by coastal erosion. In order to protect the buildings and land, coastal erosion must be controlled by mitigation options that are based on scientific data, wave and current climate along the East African region are generally controlled by the seasonal monsoon winds. During the north-east monsoon period when Winds blow from the Northeast, the wind-generated waves approach the coast from the northerly direction and produce long-shore Currents With a southerly component. During the southerly monsoon …

Stress Conditions In The Kilombero Rift, Central Tanzania, A Mruma

Tanzania Journal of Engineering and Technology (TJET)

The ancient and current Stress conditions at the northwestern flank of the Kilombero Rift are assessed in this paper. Neoproterozoic Stresses in the area were associated With 3200/200 trending principal axis of straining in the rocks. Ihis deformation imparted Precambrian ductile gneissic and concordant mineral foliation with attitude Of 0200/3$WNW, 3200/200 trending b•minerai lineation and isoclinal folds With axes trending parallel to the mineral lineation.phanerozoie deformations are mainly of pennvrriasic and Cenozoic periods. Both Of the two episodes Of deformation had constant orientation of princi axes of stresses with trending 0600/020, 02 trending 1600/800 and trending 33 1100. Stress conditions …

Electrokinetic Cha Raci'erisation Of Colloidal A-Alumina, J Ntalikwa

Tanzania Journal of Engineering and Technology (TJET)

Electrophoretic mobility (uD is an important rneasurable parameter in studying the electrokinetic properties of a colloid dispersion. This parameter is Often convened into zeta potential (C) Which piays a great role in thc description Of the stability towards aggregation Of dispersed particles. In this paper, measurements of Of colloidal a-alumina dispersed in various concentrations of electrolyte arc reported. It was observed that, the isoelectric points (the pH at which us = O) occurred at 7.52 ± 0.32, 8.05 ± 0.11 and 7,95 ± 0.18 in Naci, KCI and NaNOs respectively. The isoelectric point was observed to be a function Of …

Comparative Analysis Of Rng K-E And 'Standard' K-C Models For Fluid Flow Around A Cylinder, A Temu

Tanzania Journal of Engineering and Technology (TJET)

A two-dimensional computational scheme for simulating fluid flow around a cylinder was investigated. RNG (Re-NOrmalisation Group) and 'standard' turbulent closure models were used. simulation was implemented with assistance OfFLOW-3D computational fluid dynamics (CFD) code. The governing equation Of fluid motion, in Eulerian form, included body forces as well as surface forces. The computational model predictions for fluid velocity showed good agreement between the two models. Comparison Of the viscosities showed a large deviation from the two models, with RNG k-E model giving a better approximation. Comparison Of the velocity around the cylinder, as obtained from RNG k-c model, with approximation …

Recyclability Of Modified Ps-Aq Pulps At Around Kappa 30, Rwaichi Minja

Tanzania Journal of Engineering and Technology (TJET)

Bleachable grade pulps prepared from Nonvegian softwood spruce chips while simulating possible alternatives of improving pulp yield by application Of polysulphide (PS) and anthraquinone (AQ) have been used in this study. The tests for recyclability were performed on hydrogen form pulps. The pulps considered were Iso- Thermal cooking (ITC) kraft pulp which was used as a reference pulp, conventional PS-AQ pulp, soda PS-AQ pulp and kraft PS-AQ pulp. The loss Of swelling ability (homification) Of the pulps, was determined by measurement of water retention value (W R V). The results showed that, PS-AQ pulps had similar or slightly better swelling …

Baseflow Separation Based On Storage-Outflow Modelling Of Streamflow Recessions, With Application To Semi- Arid Catchments In Tanzania, S Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

Discharge in many rivers is Often fed by baseflow provided by drainage of the saturated zone in the shallow permeable soils. It is becoming clear that the outflow from this saturated zone is not linear proportional to storage as is commonly assumed in many algorithms. The objectives Of this study theretore, are first to explore the extent to which the assumption of linearity in storage-outflow relationships is valid and secondly to introduce an alternative approach to baseflow separation algorithms for estimating direct mnoff time series. Numerical analysis Of streamflow recessions from the semi-arid catchments of the Great Ruaha basin in …

A Study Into Lack Of Product Innovation And Business Techniques At The Tricycle Workshop And Rrs Lessons To Small Companies, E Elias

Tanzania Journal of Engineering and Technology (TJET)

A study was carried out at the Tricycle Workshop (TW) which was facing the problem of !ack of orders and therefore stagnation Of business. The objective of the study was to find out reasons for this situation and to propose possible remedial solutions. The study was conducted using the principles of the Product Innovation process where internal and external issues related to the business Of the company were investigated for information. Analysis Of information obtained indicated that the bad situation of the TW had mainly been caused by the nature of the tricycles-supply system whereby users (disabled persons) are unable …

Retention Of Female Faculty Members, Susan L. Murray, Mariesa Crow, Suzanna M. Rose

Engineering Management and Systems Engineering Faculty Research & Creative Works

The recruitment and the retention of female undergraduate and graduate students into engineering courses is discussed. A similar challenge lies in recruiting female faculty member from the limited pool of candidates in several fields at most universities. It is found that about half the females who were hired did not stay at the university. It is suggested that programs should be introduced to encourage mentoring and career development as such improvements would benefit all faculty members both female and male.

Apparatus And Method For Two Stage Hybrid Space-Time Adaptive Processing In Radar And Communication Systems, Todd B. Hale, Michael C. Wicks, Raviraj S. Adve

AFIT Patents

A Two-Stage Hybrid algorithm offers significant improvement in the false alarm rate and detection performance of Space-Time Adaptive Processing in non-homogeneous environments for both radar and digital communications. The first stage analyzes data from a range cell of interest by direct data domain processing, suppressing discrete interferers within the range cell of interest. The second stage implements a purely statistical STAP algorithm, preferably an enhanced version of the Joint-Domain Localized ("JDL") statistical algorithm. For radar this second stage estimates the interference within the range cell of interest from the surrounding range cells. For a communications system, the second stage estimates …

Ingaasnsb/Gaas Quantum Wells For 1.55 Μm Lasers Grown By Molecular-Beam Epitaxy, Xiaodong Yang, J. B. Heroux, L. F. Mei, W. I. Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

InGaAsNSb/GaAs quantum wells (QWs) were grown by solid-source molecular-beam epitaxy using a N₂ radio frequency plasma source. The effect of adding Sb during growth of InGaAsN/GaAs QWs was studied. X-ray diffraction, reflection high-energy electron diffraction and transmission electron microscopy studies indicate that Sb suppresses the three-dimensional growth and improves the interface of the QWs. X-ray diffraction and secondary ion mass spectroscopy analysis show that Sb gets incorporated into the quantum well, which becomes a quinternary compound that was previously unexplored. The introduction of Sb during growth of InGaAsN/GaAs QWs significantly enhances the optical properties of the QWs. 1.53 /spl …

Dislocation-Controlled Perforated Layer Phase In A Peo-B-Ps Diblock Copolymer, Lei Zhu, Ping Huang, Stephen Z. D. Cheng, Qing Ge, Roderic P. Quirk, Edwin L. Thomas, Bernard Lotz, Jean-Claude Wittmann, Benjamin S. Hsiao, Fengji Yeh, Lizhi Liu

College of Polymer Science and Polymer Engineering

Small angle x-ray analyses show that the shear-induced hexagonal perforated layer phase in a poly(ethylene oxide)-b-polystyrene diblock copolymer consists of trigonal (R3(overbar)m) twins and a hexagonal (P6(3)/mmc) structure, with trigonal twins being majority components. Transmission electron microscopy reveals that the hexagonal structure is generated through sequential intrinsic stacking faults on the second layer from a previous edge dislocation line, while the trigonal twins are formed by successive intrinsic stacking faults on neighboring layers due to the plastic deformation under mechanical shear.

Water Infiltration Study On Slopes, Tian Huat Low

Student Works (2000-2009)

Study was carried out in the field using infiltrometer and in the laboratory using “sprinkler model”. Studies on infiltration have always been part of hydrology and Irrigation engineering. Infiltration forms the link between surface and subsurface hydrology. Infiltrated water must be quantified and subtracted from the surface runoff in flood prediction studies and surface water management. Numerous researchers have actually incorporated infiltration into the slope stability analysis of the residual soils, e.g., Othman (1990), Affendi et. al.(1992, 1996) and Suhaimi and Abdul Rahman (1997). In most analysis of slope stability, the infiltration rate of the slopes is assumed uniform throughout …

Asee Student Chapters: From Student Members To Faculty, Jennifer Kadlowec, Kurt Degoede, Trevor S. Harding, Christian Lorenz

Materials Engineering

The University of Michigan Student Chapter of the American Society for Engineering Education has grown from a small core group of founding members, who organized panel discussions for the graduate student community, into a flourishing student organization, which continues to grow in membership and events. The purpose of this paper is to promote graduate student chapters of the ASEE and demonstrate the positive impact that student member participation has had, particularly for those who have recently entered academia. Many events and activities of the University of Michigan Student Chapter of the American Society for Engineering Education (UM-ASEE Student Chapter) will …

The Foundation Series On Corrosion: Integrating Science, Math, Engineering & Technology In A Lab Setting, Linda Vanasupa, Heather Smith, Blair London, Katherine C. Chen, David Niebuhr, Lanny Griffin, Jeff Jones

Materials Engineering

We have developed a laboratory module focusing on the subject of corrosion. The module itself is designed to be completed in one three-hour session. It consists of three parts: I. The Impact of Corrosion Media, II. The Impact of Corroding Materials, III. The Impact of Anode/Cathode Sizes. Our objectives in developing this module were to address the need for clear bridges between math, science and technology in the engineering curriculum and to provide a means of faculty development primarily at community colleges. As a result, it was designed to allow the engineering student to experience the synergy of science, math …

Useful Approaches To Preventing Academic Dishonesty In The Classroom, Trevor S. Harding

Materials Engineering

Over the past three decades, academic dishonesty (a.k.a. cheating) has become an increasingly common occurrence among college-aged students, and engineering students are known to be among the most frequent culprits. At most universities, cheating is dealt with after the fact. Few institutions go beyond drafting an academic integrity policy to prevent cheating before it happens. The same situation exists in the classroom. The majority of college professors report doing little or nothing to reduce the frequency of cheating in their classes, usually because of a lack of awareness of its occurrence. And when cheating is observed, faculty overwhelmingly choose to …

On The Frequency And Causes Of Academic Dishonesty Among Engineering Students, Trevor S. Harding

Materials Engineering

According to studies of self-reported academic dishonesty conducted over time, cheating among college students has been on the increase since at least the 1940’s. This is especially true for engineering students who are now among the most likely to cheat compared to other disciplines. This paper will present a synopsis of the literature on academic dishonesty. In addition, the results of a pilot study on cheating among engineering students conducted at a small mid-western private engineering school are described. Engineering students in an introductory engineering materials course were asked to complete a survey on their perceptions of cheating; therefore, all …

Greasing The Tenure Track 2, David Braun

Electrical Engineering

Some new faculty must balance the competing demands of the desire to teach effectively while maintaining a heavy teaching load. Oh, and, by the way, along the way to the tenure hurdle, research, professional development, and service duties may distract from family, friends, and real life. Based on the author’s participation in the NSF's New Century Scholars (NCS) Workshop at Stanford University as both a scholar (1999) and, subsequently, as a senior scholar (2000), this paper summarizes six useful tips for tenure-track faculty. This second paper in the series by NCS senior scholars provides the perspective of an engineering educator …

Computer-Aided Engineering For Tool Design In Manufacturing Engineering Curriculum, Daniel J. Waldorf

Industrial and Manufacturing Engineering

At Cal Poly – San Luis Obispo, a variety of tool design issues are covered in a junior-level manufacturing engineering course called Tool Engineering. In the course, designing fixtures – for any process – is a major component of the content. The process of designing a fixture is similar to the method a mechanical engineer would use to design a new product. The course is therefore an excellent opportunity to teach design principles to manufacturing engineers. This project involves an attempt to introduce computer-aided methods, including the finite element method (FEM), for analysis of tool design into the Tool Engineering …

Solar Cooker Reflector Optical Evaluation And Design Evolution, Florida Solar Energy Center, Ross Mccluney

FSEC Energy Research Center®

Solar Cooker Reflector Optical Evaluation and Design Evolution

Using Lip Features For Multimodal Speaker Verification, Xiaozheng Zhang, Charles C. Broun

Electrical Engineering

With the prevalence of the information age, privacy and personalization are forefront in today's society. As such, biometrics is viewed as an essential component of current and evolving technological systems. Consumers demand unobtrusive and non-invasive approaches. In our previous work, we have demonstrated a speaker verification system that meets these criteria. However, there are additional constraints for fielded systems. The required recognition transactions are often performed in adverse environments and across diverse populations, necessitating robust solutions.

We propose a multimodal approach that builds on our current state-of-the-art speaker verification technology. In order to maintain the transparent nature of the speech …

Roll Motion Of A Roro-Ship In Irregular Following Waves, Jianbo Hua, Wei-Hui Wang

Journal of Marine Science and Technology–Taiwan

A RoRo-ship usually has a fine hull form with large flare at bow and stern. In order to achieve large cargo space, large ratio of the beam to draught are quite common for this kind ship. Such a hull configuration can be subjected to considerable variation of the metacentre height as she sailing in waves. As a consequence the parametric excitation becomes considerably great so that a large roll motion appears. This is a strongly nonlinear problem. A simplified model is formulated in this paper to take account for the parametrically excited roll motion of a RoRo-ship in irregular following …

Dual Boundary Integral Equations For Helmholtz Equation At A Corner Using Contour Approach Around Singularity, I-Lin Chen, Ming-Te Liang, Shyh-Rong Kuo, Jeng-Tzong Chen

Journal of Marine Science and Technology–Taiwan

A dual integral formulation for the Helmholtz equation problem at a corner is derived by means of the contour approach around the singularity. It is discovered that employing the contour approach the jump term comes half and half from the free terms in the L and M kernel integrations, respectively, which differs from the limiting process from an interior point to a boundary point where the jump term is descended from the L kernel only. Thus, the definition of the Hadamard principal value for hypersingular integration at the collocation point of a corner is extended to a generalized sense for …

The G-Based Jordan Algebra And Lie Algebra With Application To The Model Of Visco-Elastoplasticity, Chein-Shan Liu

Journal of Marine Science and Technology–Taiwan

By a matrix representation the g-based Jordan algebra [1] is proved to form a g-based Lie algebra under the commutator product. Then we derive a new dynamical system based on the composition of the g-based Jordan and Lie algebras, which possesses internal symmetry group DSOo(n,1), and its projection PDSOo(n,1). Utilizing this concept we obtain a linear representation of a constitutive model of visco-elastoplasticity with large deformation. The irreducible representation in the vector space admits of the projective dilation proper orthochronous Lorentz group PDSOo(5,1) in the visco-elastoplastic phase and the dilation special Euclidean group DSE(5) in the viscoelastic phase. The input …

Resonance Of Continuous Bridges Due To High Speed Trains, Jong-Dar Yau

Journal of Marine Science and Technology–Taiwan

In this paper, the vibration of continuous bridges subjected to the passage of high-speed trains is studied. Only the bridges with uniform spans are considered and the train moving over a bridge is modeled as a series of moving loads. According to the resonant formula of simple beams to moving loads, the effect of multiple resonant peaks for continuous bridges subjected to high-speed trains can be determined by analogy method. Based on the finite element method, the effect of the number of spans on the impact response of the continuous beams is presented. The results show that the more the …

Design And Preliminary Test On The Integration Of Weather Data In Ecdis For Marine Navigation, Shwu-Jing Chang

Journal of Marine Science and Technology–Taiwan

The incorporation of marine weather information into Electronic Chart Display and Information System (ECDIS) has become a major issue common to international organizations such as IMO, IHO, and WMO. It is believed that this will further enhance the effectiveness of ECDIS as a tool of decision support to mariners for safe and efficient navigation. This paper first identifies essential items of marine weather information to be integrated into ECDIS. The data structure, formats, and symbology for the display and updating of weather data in ECDIS are then proposed according to related international standards. Potential use of weather data in ECDIS …

The Design Of Fuzzy Collision-Avoidance Expert System Implemented By H∞ - Autopilot, Cheng-Neng Hwang, Joe-Ming Yang, Chung-Yen Chiang

Journal of Marine Science and Technology–Taiwan

Collision avoidance is one of the urgent topics on ship voyage at sea. Experts’ experience is still essential when a ship is in the danger of colliding with the others nowadays although a lot of electronic voyage supported apparatuses have been equipped on ships. To include these experts’ experiences to resolve the problems of collision, we design a fuzzy collision-avoidance expert system that includes a knowledge base to store facts and rules, an inference engine to simulate experts’ decision and a fuzzy interface device. Either a quartermaster or an autopilot system can then implement the avoidance action proposed in the …

Predicting The Integrity Of Existing Prestressed Concrete Bridge Deck Using Sonic Method, Ming-Te Liang, Jyi Wu

Journal of Marine Science and Technology–Taiwan

The principal objective of this paper was provided a general idea for predicting the integrity of existing prestressed concrete bridge decks by using sonic method. The governing equation is a onedimensional wave equation with initial conditions. The method of Fourier transform was adopted for seeking D'Alembert's solution which is an analytical solution of the governing equation. Furthermore, the wave formulae such as displacement, velocity, force and stress waves were derived from the analytical solution. If the viscosity effect of material was neglected, then the elastic wave can be reduced as the sonic wave. Through these sonic wave formulae, the damage …

A Numerical Model For The Cyclic Instability Of Thermally Grown Oxides In Thermal Barrier Systems, Anette M. Karlsson, A. G. Evans

Mechanical Engineering Faculty Publications

Morphological instability of the thermally grown oxide (TGO) is a fundamental source of failure in some thermal barrier systems. The instabilities occur when initial non-planarity in the TGO grows in amplitude as the system experiences thermal cycling. By numerical means, this study explores how these instabilities are linked to constituent properties. The associated phenomena involve oxidation of the TGO, plastic flow of the bond coat, thermal expansion misfit between the TGO, bond coat and substrate, and stress relaxation in the TGO at high temperature. A key implication of the simulations is that the incidence of reverse yielding upon reheating differentiates …

Increasing Power Density Of Lsgm-Based Solid Oxide Fuel Cells Using New Anode Materials, Kevin Huang, Jen-Hau Wan, John B. Goodenough

Faculty Publications

Chemical reactions between the superior perovskite oxide-ion conductor Sr- and Mg-doped LaGaO₃ (LSGM), CeO₂, and NiO have been studied by powder X-ray diffraction. The results showed that an extensive reactivity occurs as a result of La migration driven by a gradient of La chemical activity. La migration across the LSGM/electrode interfaces in a fuel cell leads to the formation of resistive phases at the interface, either LaSrGa₃O₇ or LaSrGaO₄. Use of 40 mol % La₂O₃ -doped CeO₂ as an interlayer between anode and electrolyte as well as in …

Controlled Buckling Breakaway Cable Terminal, John D. Reid, John R. Rohde, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A crash attenuation apparatus for use with a guardrail system having rail posts and rail elements. An impact head has a buffer nose section and a rail post breaking beam system. The post breaking beam system has upper and lower breaking beams attached to the head. A guide tube is attached to the side of the head. A strut member extends from a first attachment point on the rail element to a second point downstream. Upon impact by a vehicle, the head breaks the first rail post, before impacting the strut and buckling the rail element downstream.