Philip T. McCreanor

Municipal solid waste in situ moisture content measurement using an electrical resistance sensor

Moisture content (MC) is a crucial parameter for degradation of solid waste in landfills. Present MC measurement techniques suffer from several drawbacks. A moisture sensor for measurement of in situ moisture content of solid waste in landfills was developed. The sensor measures the electrical resistance across the granular matrix of the sensor, which in turn can be correlated to moisture content. The sensor was also equipped with a thermocouple and tubing that permits simultaneous measurement of temperature and gas sampling. The electrical conductivity of the surrounding moisture and the temperature in the matrix both affect the resistance measurements. This paper describes the results of laboratory experiments designed to select the appropriate granular media particle size, measure the influence of moisture electrical conductivity and temperature, and develop calibration relationships between measured resistance and gravimetrically determined moisture content. With a few limitations, the sensor is able to detect MC of solid waste under conditions allowing moisture movement into the sensor. The application of this technique shows promise for use in bioreactor landfills where high moisture contents are expected and desired.

Quantitatively assessing an outcome on designing and conducting experiments and analyzing data for ABET 2000

The Mercer University School of Engineering (MUSE), USA, identified eight outcomes to assess for the accreditation process. MUSE Outcome #4 stipulates that students should be able to design and conduct experiments and analyze data. The committee charged with assessment of Outcome #4 identified four separate skills associated with this outcome; conducting experiments, analyzing experimental data, interpreting experimental data and designing experiments. The committee determined that assessment of this outcome required documentation of the number of student experiences with each of the four skills and the overall student performance level on each of these skills. A skill assessment worksheet was developed for use in the grading of any activity related to Outcome #4. The worksheet quickly identifies which of the four skills the activity incorporates as well as the performance of the students on each of the individual skills. This worksheet was distributed to instructors teaching courses that contain a significant content related to this outcome. Data collected from courses in Industrial Engineering, Biomedical Engineering, and Electrical Engineering taught during the Fall of Semester of 2000 suggests that MUSE has been successful at meeting Outcome #4. The data also indicates that the skill assessment worksheet was an efficient and accurate method for collecting quantitative data and identifying weakness in the assessment process. Modifications made to the worksheet by professors to accommodate their personal grading scheme demonstrates that the tool has enough flexibility to be used across multiple disciplines and grading styles while still providing the data required,for assessment of Outcome #4. This paper presents the skill assessment worksheet, data collected using the worksheet, and instructor comments on use of the worksheet.

F-Scan Analysis of Prosthetic Fittings through Mercer on Mission Vietnam

Mercer on Mission Vietnam is an annual service learning course which students spend time fitting prosthetic limbs on amputees. The prosthetic utilized in these trips includes a universal socket designed at Mercer University. The design is a low cost prosthesis that accommodates as many impoverished amputees as possible. During the summer of 2013, 18 students and 3 professors fitted 272 amputees. Fifty-three sets of Tekscan F-Scan Plantar Pressure data were collected. Students analyzed the plantar pressure data and tested for statistical trends between age, weight, height, amputation date, and gender to seek trends that could lead to improvements for the next trip. None of the five factors tested correlated with the quality of prosthetic fit. It was determined that a more systematic method of F-Scan data collection was needed in order to increase consistency and sample size for more in depth trend analysis.

Introducing fundamental technical concepts in a freshman design course

Freshman design courses are typically hampered by the fact that freshmen, even in their second semester, have had very little in the way of engineering course work. In the past, this situation has made it impractical for the instructors teaching Introduction to Engineering Design to require students to perform any meaningful calculations associated with their designs. In the Spring Semester of 2002, the course content was modified to include the introduction of fundamental technical concepts. The intent of these seminars was to provide students with engineering tools and quantitative methods for analyzing their designs prior to construction. This paper presents detailed information on the specification of one of the design projects, the design kit contents for this project, and the learning objectives from the technical seminars. Finally, a brief discussion of the impact of the technical seminars on the course is provided.

Design, Operation, and Analysis of a Biological Sand Filter Using Copper as a Disinfectant

Aqua Clara International (ACI) is a nonprofit organization that uses biological sand filters (BSFs) to provide economical, clean water to families in developing countries. ACI often recommends loading 20 L/d in BSFs in which a brass alloy is included as a disinfectant. A bench-scale study was conducted to investigate the effectiveness of using copper as the disinfectant. Five filters were constructed to compare different arrangements and amounts of copper shavings to a control, Column 1. The control was modeled after ACI design specifications but no metallic disinfectant was included. Columns 2 – 5 were also scaled according to ACI recommendations. Columns 2 and 3 each contained 4.7 g of copper, and Columns 4 and 5 each contained 2.35 g. In columns 2 and 4, copper was placed in a single layer; while in Columns 3 and 5, the copper was dispersed throughout the fine sand. After 31 days of testing, the average removal efficiency for total coliforms in Columns 1 – 5 was 96.5%, 93.9%, 97.4%, 95.4%, and 97.5% respectively. A single, 20 L/d, BSF was constructed with 94 g of copper dispersed throughout the fine sand layer. The average removal efficiency for fecal coliforms and turbidity was 97.3% and 65.7%, respectively.