https://dc.etsu.edu/oer-guitars-images-complete/1008/thumbnail.jpg

https://dc.etsu.edu/oer-guitars-images-complete/1009/thumbnail.jpg

https://dc.etsu.edu/oer-guitars-images-complete/1010/thumbnail.jpg

https://dc.etsu.edu/oer-guitars-images-complete/1011/thumbnail.jpg

https://dc.etsu.edu/oer-guitars-images-complete/1012/thumbnail.jpg

https://dc.etsu.edu/oer-guitars-images-complete/1013/thumbnail.jpg

https://dc.etsu.edu/oer-guitars-images-complete/1014/thumbnail.jpg

The ETSU Guitar Project’s Open Education Resource (OER) site is a repository of shareable files developed and used in the design & fabrication of electric and acoustic guitars. Begun in 2010, the ETSU Guitar Building Program is affiliated with the NSF-sponsored, national STEM Guitar Project to increase student engagement in the STEM disciplines from K-12 to Higher Ed. Guitar design, prototyping & build activities in the ENTC 3600 Manufacturing Technologies course use a hands-on mix of 2D CADD, 3D modeling, traditional woodworking, CNC routing and laser etching operations in a custom shop-type environment to create unique electric solid body and semi-hollow body electric guitars. Beginning in 2019, the Engineering Technology program faculty began partnering with faculty in ETSU’s groundbreaking Department of Bluegrass, Old Time, and Roots Music Studies program in building acoustic instruments. Designs of common and specialty acoustic instrument building including luthiers’ tooling, molds, templates, jigs and fixtures as well as alternative bracing are available from this repository. / https://dc.etsu.edu/etsu-oer/1009/thumbnail.jpg

An extensive laboratory test program was conducted to analyze and compare the cation exchange processes in three different varieties of sodium bentonite (Na-B) geosynthetic clay liners (GCLs) over increased conditioning durations up to 32 days and investigate the effects of temperature, solution strength, and applied stress. The goal of this test program was to establish whether the variables of temperature, solution strength, and applied stress improved or degraded the engineering properties of GCLs in laboratory testing and municipal solid waste (MSW) landfill applications. The GCLs were conditioned in liquids of increasing ionic strength, using deionized water and 2, 50, and 200 mM CaCl2 solutions to represent control, pore water, mild MSW leachate, and harsh MSW leachate. Conditioning periods were 1 to 32 days. Tests were conducted at 5°C, 20°C, 40°C, and 60°C and at 0 kPa, 30 kPa, and 500 kPa to represent stresses experienced by the cover and bottom liner. These variables were selected to represent geoenvironmental conditions observed in MSW landfill systems. Cation exchange processes in the bentonite component of the GCL were quantified by measuring the bound cation (BC) concentrations and cation exchange capacities (CEC) of the specimens and by conducting index testing to determine the dimensional measurements, final moisture content, and swell index of the conditioned bentonite. The temperature, electrical conductivity, total dissolved solids, sodium and calcium concentrations of the conditioning fluids were measured periodically for all specimens and the sodium concentration was measured for all specimens tested at applied stress. Temperature, solution strength, and applied vertical stress all affected the cation exchange processes in the bentonite component of GCLs. Increasing temperature, increased solution strength and decreased applied vertical stress were observed to increase cation exchange processes. The results of this study can be applied to quality assurance evaluations of in-service GCLs. In addition, the observation of the study indicates that GCLs used in cover liner systems for MSW landfills may be susceptible to high rates of cation exchange due to low overburden stresses and high surface temperatures. GCLs used in bottom liner may experience inhibited cation exchange rates as a result of high vertical stresses and relative lower temperatures.

In this research, a proton exchange membrane fuel cell (PEMFC) sensor was investigated for specific detection of volatile organic compounds (VOCs) for point-of-care (POC) diagnosis of the physiological conditions of humans. A PEMFC is an electrochemical transducer that converts chemical energy into electrical energy. A Redox reaction takes place at its electrodes whereas the volatile biomolecules (e.g. ethanol) are oxidized at the anode and ambient oxygen is reduced at the cathode. The compounds which were the focus of this investigation were ethanol (C2H5OH) and isoflurane (C3H2ClF5O), but theoretically, the sensor is not limited to only those VOCs given proper calibration. Detection in biosensing, which needs to be carried out in a controlled system, becomes complex in a multivariate environment. Major limitations of all types of biosensors would include poor selectivity, drifting, overlapping, and degradation of signals. Specific detection of VOCs in multi-dimensional environments is also a challenge in fuel cell sensing. Humidity, temperature, and the presence of other analytes interfere with the functionality of the fuel cell and provide false readings. Hence, accurate and precise quantification of VOC(s) and calibration are the major challenges when using PEMFC biosensor. To resolve this problem, a statistical model was derived for the calibration of PEMFC employing multivariate analysis, such as the “Principal Component Regression (PCR)” method for the sensing of VOC(s). PCR can correlate larger data sets and provides an accurate fitting between a known and an unknown data set. PCR improves calibration for multivariate conditions as compared to the overlapping signals obtained when using linear (univariate) regression models. Results show that this biosensor investigated has a 75% accuracy improvement over the commercial alcohol breathalyzer used in this study when detecting ethanol. When detecting isoflurane, this sensor has an average deviation in the steady-state response of ~14.29% from the gold-standard infrared spectroscopy system used in hospital operating theaters. The significance of this research lies in its versatility in dealing with the existing challenge of the accuracy and precision of the calibration of the PEMFC sensor. Also, this research may improve the diagnosis of several diseases through the detection of concerned biomarkers.