Engineering Commons^™

An Investigation On The Processing And Characterization Of (Thallium(0.5-X) Lead(0.5-X) Europium(2x)) Strontium(2-Y) Barium(Y) Calcium(2) Copper(3) Oxygen(Z) High-Temperature Superconductor To Determine The Optimum Barium Concentration And Study The Effects Of Doping Europium In Thallium And Lead Sites, Zifan Ju

Dissertations and Theses @ UNI

This research focused on (Tl_0.5-xPb_0.5-xEu_2x)Sr_2-y Ba_yCa₂Cu₃O_z compound to determine the optimum y (Barium concentration), and then studied the effects of doping Eu in Tl, Pb sites. Studies on optimum y give rise to a high quality superconducting material as a target material for sputter deposition of thin films for electronics applications. Studies on doping Europium (Eu) is a new investigation and might lead to better understanding of the structural properties of the superconductor.

The experiment was conducted in three steps as follows:

1. Optimizing the sample fabrication …

Maintenance Conditions And Occupant Behavior In Government Provided Housing In Lagos, Nigeria, Paul Abayomi Bajere

Dissertations and Theses @ UNI

Maintenance conditions and occupant behavior towards maintenance in government housing in developing countries are universal problems. Perceptions, construction technology, competencies, tenureship, cultural tradition, and demographic factors have been identified as major constraints influencing housing maintenance behavior. There was a need for this study because limited literature exists on maintenance of urban government provided housing in Nigeria. Also, the degree of success of the government's efforts concerning environmental cleaning has not been remarkable.

The primary purpose of this study was to investigate the maintenance of government provided housing, as perceived by the residents and observed by the researcher, to determine the …

Effect Of Light Source On The Sorting Performance Of A Vision-Based Robot System, Johnny T. Li

Dissertations and Theses @ UNI

Industries look toward computer vision as a means to automate materials handling. To make this choice more appealing, useful and feasible vision applications must be explored. However, illuminance variation in the factory environment can undermine the capability and applicability of vision-based control systems. The purposes of this study were (a) to design and develop a vision-based robot material sorting system, (b) to determine the optimal settings for this system under fluorescent and incandescent lighting for two different color parts on a moving conveyor, and (c) to determine the sorting performance of this system under each light source.

The main components …

Effects Of Refrigeration And Cryogenic Treatments On Austempered Ductile Iron, Gerard R. Thiel

Dissertations and Theses @ UNI

Low temperature treatment, as a method of improving mechanical properties of metals, has been studied and used for well over 60 years. Until recently these treatments have been limited to hardness and wear improvements of high alloy irons and steels. The purpose of this research is to determine the effects of refrigeration and cryogenic treatments on the mechanical properties, including hardness and tensile strength of austempered ductile iron.

This research included the production of a high strength ductile iron of low alloy content capable of being used in either the as cast, conventionally heat treated or austempered condition. Refrigeration and …

A Comparison Of Measurement Reliability Between A Sonic Digitizer And A Tape Measure On A Complex Three-Dimensional Object, Diane Darlene (Wheeler) Schou

Dissertations and Theses @ UNI

Digitizers and scanners have begun to replace traditional devices for measuring three dimensional objects. However, there is a shortage of relevant research to compare digitizer tools with other measuring devices. The objective of this study was to compare the measurement reliability of a sonic digitizer to a traditional measuring tool, the tape measure, for measuring a complex, three-dimensional object. It was hypothesized that:

1. H₁ Data from measurements with the digitizer vary less than data from measurements with a tape measure at the 0.05 level of significance.
2. H₂ The data from eight complex surface measurements taken with a digitizer …

The Effects Of Telephone Technology On Saudi Arabian Society, Khalid I. Otibi

Dissertations and Theses @ UNI

The current research explores the significance of the introduction of telephone technology into Saudi Arabia. The problem addressed by the research was to identify and describe the cultural and economic significance that the telephone has had in Saudi Arabia. The purpose of the research was specifically to study the significance that telephone technology has in the three areas of family ties, business, and transportation. The methodology began with the development a data-collection document. An English version of the document was administered as a pilot test to students at the University of Northern Iowa. This pilot test revealed that the document …

An Investigation On Using Solid Waste Materials As Aggregate Substitute In Cementitious Concrete Composites, Ibrahim Hussein Shehata

Dissertations and Theses @ UNI

The problem of disposing and managing solid waste materials in the United Slates and other industrial countries has become one of the major environmental, economical, and social issues. A complete waste management system including source reduction, reuse, recycling, landfilling, and incineration needs to be implemented to control the increasing waste disposal problems. Of the above options, recycling is the most promising waste management process to the disposal of materials in the waste stream. One of the most promising markets to utilize recycled waste materials successfully on an open-loop basis is the construction industry.

The purpose of this research study was …

An Investigation Of Diameter Measurement Repeatability Using A Coordinate Measuring Machine And A Multi-Baseline Repeatability Assessment Methodology, Bruce Marsh

Dissertations and Theses @ UNI

The need for reliable and consistent measurement has become more acute with the use of statistical process control (SPC), gage repeatability and reproducibility (Gage R&R) assessment, and high precision, computer-controlled gaging systems. Although it is often overlooked, the inspection methodology under which various features are inspected has an impact on Gage R&R results. This notion was confirmed when a 1993 thesis study substantiated inspection methodology as a source of measurement variability in direct computer-controlled, coordinate measuring machines (DCC/CMMs). Although this study explored a methodology to bring measurement variability under statistical control, the tested assessment methodology--single baseline repeatability assessment--was not validated. …

The Effects Of Post Inoculant Additions On Ductile Iron Fade, Travis James Frush

Dissertations and Theses @ UNI

This study involved the investigation of three specific, commercially available, post inoculants for ductile iron and their effect on the magnesium fading rate and chill reducing tendency in a low volume production environment. Although fading effects of ductile iron have been extensively investigated, in general, they apply to high volume production operations. Unfortunately, for the smaller foundry operations, many of the process solutions proposed for the prevention of the fading effects are not applicable or practical. In addition to the small production operations, new process technologies are also excluded from many of these process solutions. For this reason, a study …