Industrial Engineering Commons^™

Investigation On Distribution Of Cast Properties On Aluminum Plates Poured By Side Gating Technique, Joseph Runyoro

Tanzania Journal of Engineering and Technology (TJET)

Casting technologies wllich improve casting yield and intenzal sOllndness of thin wall cast components are of particular interest to industry especially for critical applications. The main aim of fOll1ldries is to achieve castings free from defects at low cost. It hils been thought that pouring casting by side ingate technique improve directional solidification as the metal stays hot for long time in the feeder cum ingate. Experiments were carried alit IIsing a side gating technique to cast a number of 300 mm x 300 mm LMO and LM 25 plates in furall and pepset sand moulds. The thickness used was …

Geometric Programming As A General Method For Phase And Reaction Equilibrium Calculations, Godwill Mrema

Tanzania Journal of Engineering and Technology (TJET)

Geometric programming has been used to calculate a large mtmber ofdifferent ideal and non-ideal equilibria, including, for reaction and For non-ideal Systems the primal program is solved a number Of times With the nan-ideal terms fixed each time. After each primal solution, the nan-ideal terms are "'hdated using the corresponding dun! solution. This iteration generally converges. We have included one counter-example, where the failure is caused by the equation Of state, which Cannot giu• correct roots.

Performance Of Aerobic Bioreactors During Treatment Of Tanning Industry Wastewater, Samwel V. Manyele

Tanzania Journal of Engineering and Technology (TJET)

The performance of aerobic bioreactors loaded with novel biomass support (the KMT® support particles) during the treatment of tanning industry wastewater is presented in this paper. The wastewater samples were collected from TANWAT Company in Njombe, which extracts tannins from barks of the wattle tree. The wastewater generated from T ANWAT is very acidic with high loading of organic compounds, which are very complex and difficult to biodegrade using conventional methods. The paper introduces a new technology for treatment of heavily loaded industrial wastewater, like tannins, that is the Three-Phase Fluidized Bed Bioreactor (TPFBB) which utilizes the KM'f® support particles. …

An Intervention Framework Based On A Complementary Theory Of Organizational Decline, George S. Mwaluko

Tanzania Journal of Engineering and Technology (TJET)

This paper has developed an intervention framework based a complementary theory Of Organization decline. Any management intervention effort is normally based on a certain theory of organizational decline i.e. a theory that explains the causes for failure of organizations. Four major theories Of Organisational decline were identified in the literature, reviewed and integrated into one, presumably more superior, theory of organisational decline. They included the natural selection theory, the resourc+based theory, the theory Of misperception of feed!mck and the contingency theory. The new theory was then used to guide the design of an intervention framework. The framework utas then used …

Sampling Procedure For Pavement Condition Evaluation Of Local Collectors And Access Roads, David Mfinanga

Tanzania Journal of Engineering and Technology (TJET)

Road surface condition evaluation involves the collection Of a lof Of data on different types of distresses. •lie exercise consumes a lot Of resources if the whole road section length is sureeyed and may be prone to errors as a result Of surveyors' fatigue. It is therefore important Io develop n reprevntative sample to be used When road condition manually. This study aimed nt determining sample size for condition evaluation of local collector access roads in urban areas in Tanzania. Two such roads namely l.ufungira and Kilimahewn roads respectively were selected for the study. It is recommended that a section …

Towards Effective Online Learning Implementation In Tanzanian Higher Learning Institutions: Obstacles, Challenges And Opportunities, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper identifies and discusses several influential factors as well as opportunities, associated with effective- online learning implementation in Tanzanian Higher Learning Institutions (THUs). Fourteen (14) THUs were surveyed, using face-to-face interviews in focus groups. The groups included Lecturers, Heads of ICT Departments, ICT Technical Personnel as well as Admi/:listrative Staff. Results indicate that mostly, problems with effective online implementation in THUs are centred on a severe scarcity of online resources and tools and that the main challenges lie in going beyond the process of integrating technology with their teaching curricular, so that training of both teaching and supporting staffs …

A Multidimensional Scaling And Participatory Design Approach To Classify Open Ended Aircraft Maintenance Data, Kunal Kapoor

All Dissertations

The quality assurance data to be analyzed by the web-based surveillance and auditing tool (WebSAT) is both qualitative and quantitative. The forced responses to checklist questions provide a definitive outcome identifying the effectiveness of the four quality assurance work functions. On the other hand, open-ended responses, the second type of response for capturing maintenance errors, are qualitative in nature since they reflect what the auditors and quality assurance representatives observe during their interactions at vendor locations. This research proposes to apply the statistical technique of multidimensional scaling (MDS) and the User centered Design (UCD) method of Participatory Design (PD) to …

Use Of Personas For User Interface Design: Results Of Field And Experimental Studies , Pallavi Dharwada

All Dissertations

Persona is a fictitious user serving as a role model for designers, helping them make difficult decisions from the users' perspective during the interface design process. This concept, which was introduced by Alan Cooper in 1999, has been found to be a powerful tool for engaging the designers with the users. Although personas do not replace the rich data acquired through user testing, they enhance the interface development process by focusing the designers' attention on the target user until the interface qualifies for testing. Recognizing the benefits of persona, many companies, including the Fortune 500 have embraced this concept as …

Process Modelling Support For The Conceptual Modelling Phase Of A Simulation Project, Cathal Heavey, John Ryan

Conference papers

While many developments have taken place around supporting the model coding task of simulation, there are few tools available to assist in the conceptual modelling phase. Several authors have reported the advantages of using process modelling tools in the early phases of a simulation project.

This paper provides an overview of process modelling tools in relation to their support for simulation, categorizing the tools into formal method and descriptive methods. A conclusion from this review is that none of the tools available adequately support the requirements gathering phase of simulation. This is not surprising as none of the process modelling …

Correlation Of Numerical Ability And Quality Technician Best Performers In Manufacturing Quality Control Applications, Charles Wesley Shelton

All-Inclusive List of Electronic Theses and Dissertations

The occupation of Quality Technician has many duties requiring numerical operations. Business and industry place considerable emphasis on numerical ability when evaluating the performance of a Quality Technician. In this study, the numerical ability and performance classification of Quality Technicians were analyzed using a correlation analysis. lll A single case study was used to investigate this relationship. A modified Delphi Method was used to determine characteristics of a Quality Technician. Quality Technicians were evaluated by their direct supervisor and completed a standardized numerical ability test. The evaluations by the supervisor were used to classify each technician based on their performance. …

Effect Of Chromium–Gold And Titanium–Titanium Nitride–Platinum–Gold Metallization On Wire/Ribbon Bondability, Jianbiao Pan, Robert M. Pafchek, Frank F. Judd, Jason B. Baxter

Industrial and Manufacturing Engineering

Gold metallization on wafer substrates for wire/ribbon bond applications requires good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr-Au and Ti-TiN-Pt-Au metallization systems for an optoelectronic application. Both Chromium and Titanium are used to promote adhesion between semiconductor substrates and sputtered gold films. However, both will be oxidized if they diffuse to the gold surface and result in the degradation of the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr-Au and Ti-TiN-Pt-Au, annealing, and CAN etch processes, on …

Investigation Of The Lead-Free Solder Joint Shear Performance, James Webster, Jianbiao Pan, Brian J. Toleno

Industrial and Manufacturing Engineering

Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The purpose of this study is to investigate the effects of reflow profile and thermal shock on the shear performance of eutectic SnPb (SnPb) and Sn3.0Ag0.5Cu (SAC305) solder joints. Test boards were assembled with four different sized surface mount chip resistors (1206, 0805, 0603 and 0402). Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb were developed with three levels of peak temperature (12ºC, 22ºC, and 32ºC above solder liquidus temperature, or 230ºC, 240ºC, and 250ºC for SAC …

Analysis Of A K-Out-Of-N System With Spares, Repairs, And A Probabilistic Rule, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

We consider a k-out-of-N reliability system with identical components having exponential lifetimes. There is a single repairman who attends to failed components on a first comefirst-served basis. The repair times are assumed to be of phase type. The system has K spares that can be used according to a probabilistic rule to extend the lifetime of the system. The system is analyzed using Markov chain theory and some interesting results are obtained. A few illustrative numerical examples are discussed.

Efficacy Of Virtual Models In A Production Systems Course, Lawrence Whitman, Barbara Chaparro

Publications

Wichita State University has developed an integrated set of virtual reality models of an aircraft assembly line. These models are intended to provide students an ‘artifact’ of industrial and manufacturing engineering by providing a realistic environment for initial learning and application. By utilizing a virtual model of the line, students are able to view the process and interrogate the process details, make changes and observe the effects, and gain a better understanding of the concepts and their interrelationships. This paper presents the method used to assess if virtual models (computer models of a real factory) lead to: improved perception of …

Estimation Of Liquidus Temperature When Snagcu Bga/Csp Components Are Soldered With Snpb Paste, Jianbiao Pan

Industrial and Manufacturing Engineering

Recently, the soldering of lead-free components with SnPb paste, or lead-free backward compatibility, is becoming a hot topic. One of the major challenges in backward compatibility assembly is the development of a right reflow profile for the soldering of SnAgCu Ball Grid Array (BGA)/Chip Scale Package (CSP) components with SnPb paste. If the SnAgCu reflow profile is used, the reflow temperature may be too high for other SnPb components in the same board during assembly according to the component rating per IPC/JEDEC J-STD-020C. In addition, the flux in SnPb solder paste may not function properly in such a high reflow …

Applying Lean Manufacturing Techniques To Improve The Performance Of An Emergency Department, Ramesh Pondhe

All-Inclusive List of Electronic Theses and Dissertations

The research was an attempt to apply lean manufacturing (LM) techniques, to the healthcare setting specifically to Emergency Department (ED) of a local hospital and to improve its performance. An ED is meant to attend/provide immediate care to a patient who needs medical care immediately and also balancing the care to patients with lesser acuity who arrive at the ED for treatment. The data was collected from the ED by direct observation. The data was statistically analyzed to find out the bottlenecks in the process during the course of a patient's treatment to further provide solutions and improve the performance …

Development Of A Theoretical Framework Of Distributed Cognition Phenomena In Control Centers During Crisis Conditions, Christopher J. West

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research is to develop and partially validate a theoretical framework describing distributed cognition phenomena occurring in organizational control centers functioning in crisis environments. Using a systems approach, the work synthesizes existing constructs relating to distributed cognition then supplements this knowledge with review of crisis management literature. The goal of this effort is the development of a framework for understanding the impact of crisis conditions on such phenomena occurring within the specified setting. An exploratory case study approach was used to partially validate and refine the framework by gauging its ability to interpret the impact of crisis …

Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …

Effectiveness Of Hot Isostatic Pressing On Healing Oxide Film Defects In Cast Aluminium Alloys, C Nyahumwa

Tanzania Journal of Engineering and Technology (TJET)

Hot isostatic pressing (hipping) of cast aluminium alloys is recognized as a means of providing improved internal soundness and mechanical properties of the castings. However, little is known about the limitations and potential benefit of the hipping process to produce reliable aluminium alloy castings containing oxide film defects due to turbulently filling of moulds. In this study, oxide film defects and fatigue lives of turbule''Zt filled unfiltered AI-7Si-Mg alloy castings have been characterised in as-cast and hipped. conditions to quantify the effectiveness of hot isostatic pressing on healing oxide film defects in the castings. The average fatigue life and fatigue …

Gasification Kinetics Of Ultrafine Coal Char Oxidation In Flame Reactions, G John

Tanzania Journal of Engineering and Technology (TJET)

Pulverized coal combustion is exceedingly complex with a  vast number of variables. In order to avoid the complications associated with the burning of coal char, a controlled study has been made of the oxidation of fine graphite in laminar methane-air flame as a contribution to the understanding of the more complex phenomena of the gasification kinetics of the char. The burning of methane is equivalent to the burning of volatiles and graphite oxidation is similar to that of coal char. Aspects of this have been simulated in experimental and computational studies of 4pm diameter graphite particle burning in methane -air …

Investigation Of The Stability Of Engine – Governor System Operated At Low Speeds, Cuthbert Mhilu

Tanzania Journal of Engineering and Technology (TJET)

During diesel engine operation, a tendency for the engine not to achieve a  steady idling speed has often been observed. During idling speed the engine tends to either race or stall as a result of poor and incorrect metering of the fuel, which is required for the combustion process and if severe, the engine will stop firing completely. 111 this research an investigation was made to establish knowledge on diesel engine stability operated at low speeds. The influence of a governor of an engine in the control of the engine speeds has also been investigated. In order to obtain information …

Environmental Impact Of Wetland Resources Utilization In Simuyu Basin, Tanzania, Shadrack Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

There is a growing appreciation of the natural functions of wetlands, and the values and different forms of uses that humans attach to them. Wise use and special conservation strategies are therefore needed in order to sustain their productivity. Wetlands are one of the most fruitful areas of archaeological research, and they are the ideal setting in which to study the interactions between physical processes and human actions that encapsulate and exemplify many of the themes of man's impact on his environment. But all these beneficial functions of wetlands seem to be in danger of being lost to draining and …

Study On Vortex Formation In The Pouring Basin By Direct Observation, J Runyoro

Tanzania Journal of Engineering and Technology (TJET)

Although the formation of vortex on the free surface of liquid draining from a container is often observed, relatively little is known about the phenomenon. When a liquid is drained from a container such as a bathtub through a bottom orifice, a dip on the surface known as vortex is formed. The vortex first appears as a small dimple in the free surface, which suddenly forms a cone-shaped hole. The vortex causes turbulences, which draws in air down into the orifice (drain). Generally, the issue of vortex formation is so common in our lives that possibly its occurrence seems to …

Suitability Of Crusher-Dust As Masonry Construction Material, John Makunza

Tanzania Journal of Engineering and Technology (TJET)

Crusher dust generated at Kunduchi quarries in Dar es Salaam during aggregate crushing is counted as a waste material, and some times it .is disposed away or sold at a cheap price of not more than a quarter of that of sand. A study on the use of the crusher dust as a building material has been carried out in which samples were collected and analyzed for grading (sieve analysis). In additional to that, other samples were stabilized with a small amount of cement, from which bricks were produced and tested for compressive strength. Other bricks were bonded together using …

The Decomposition Kinetics Of Solids Thermodynamic Evidence For The Enthalpy Driven Cooling Of Reaction Environment Part 2, Akwilapo D

Tanzania Journal of Engineering and Technology (TJET)

The analysis of non-isothermal kinetic data for the decomposition of calcium carbonate, CaC03 (s) ~ CaO (s) + C02 (g) in flowing nitrogen, shows that the decomposition of solids is accompanied by self-cooling/heating of the reaction environment depending on the sample mass and heating rate. The correctness of the kinetic model is established by the calculation of the enthalpy change of the reaction. This is the thermodynamic evidence of endothermic enthalpy driven cooling of the reaction environment. The enthalpy change LJH = 179.33 kJmol-1 estimated from this work for the dissociation of CaC03 is in agreement with LJH = 179.17 …

A Comparative Study Of Various Loss Functions In The Economic Tolerance Design, Jehnan Pan, Jianbiao Pan

Industrial and Manufacturing Engineering

Engineering tolerance design plays an important role in modern manufacturing. In this paper, the Kapur's model was modified so that the economic specification limits for both symmetric and asymmetric losses can be established. Three different loss functions: (1) Taguchi's quadratic loss function; (2) Inverted Normal Loss Function; (3) Revised Inverted Normal Loss Function are compared in the economic tolerance design. The relationships between the three loss functions and process capability indices for symmetric tolerance are established. The results suggest that the revised inverted normal loss function be used in determination of economic specification limits.

Plotting A Bright Future For Manufacturing Education: Results Of A Brainstorming Session, Daniel Waldorf, Sema E. Alptekin, Robert Bjurman

Industrial and Manufacturing Engineering

Manufacturing industries worldwide have undergone dramatic changes in recent years and now demand more from graduating manufacturing engineers. The effects of globalization have forever changed the parameters for success in manufacturing. Our educational institutions must respond to these changes with innovation. That agenda formed the basis for a special SME/CIRP international conference on manufacturing engineering education called “Looking Forward: Innovations in Manufacturing Engineering Education,” held in San Luis Obispo, California, June 22-25, 2005. At the meeting, manufacturing education professionals from around the world came together to share their own innovative ideas and to brainstorm ways to shape the future of …

Semester Project For Engineering Management, Paul Savory

Department of Industrial and Management Systems Engineering: Instructional Materials

This is the team-based, semester project for my advanced engineering management course at the University of Nebraska-Lincoln. This project focuses on having student teams plan a successful, professional, innovative and enjoyable professional conference. This is an activity that many of of them will have the opportunity to be involved with during their career. The project is divided into nine tasks with peer feedback and rework part of the process.

Measuring Plant-Wide Energy Savings, J. Kelly Kissock, Carl Eger

Mechanical and Aerospace Engineering Faculty Publications

This paper presents a general method for measuring plant-wide industrial energy savings and demonstrates the method using a case study from an actual industrial energy assessment. The method uses regression models to characterize baseline energy use. It takes into account changes in weather and production, and can use sub-metered data or whole plant utility billing data. In addition to calculating overall savings, the method is also able to disaggregate savings into components, which provides additional insight into the effectiveness of the individual savings measures.

Although the method incorporates search techniques and multi-variable least-squares regression, it is easily implemented using data …

Processing Model For Tungsten Powders And Extention To Nanoscale Size Range, Randall M. German, J. Ma, X. Wang, E. Olevsky

Industrial and Manufacturing Engineering

Nanoscale tungsten powders promise access to very hard, strong and wear resistant materials via the press–sinter route. A small particle size changes the response during sintering, requiring lower temperatures and shorter times to attain dense but small grain size structures. On the other hand, oxide reduction and impurity evaporation favour high sintering temperatures and long hold times. Accordingly, press–sinter processing encounters conflicting constraints when applied to small particles. Presented here is an analysis of press–sinter tungsten particle processing to isolate conditions that balance the temperature and size dependent effects. The calculations are pinned by existing data. Opportunities are identified for …