Terrence L. Chambers

Low-cost simulated MIG welding for advancement in technical training

The simulated MIG lab (sMIG) is a training simulator for Metal Inert Gas (MIG) welding. It is based on commercial off the shelf (COTS) components and targeted at familiarizing beginning students with the MIG equipment and best practices to follow to become competent and effective MIG welders. To do this, it simulates the welding process as realistically as possible using standard welding hardware components (helmet, gun) for input and by using head-tracking and a 3D-capable low-cost monitor and standard speakers for output. We developed a simulation to generate realistic audio and visuals based on numerical heat transfer methods and verified the accuracy against real welds. sMIG runs in real time producing a realistic, interactive, and immersive welding experience while maintaining a low installation cost. In addition to being realistic, the system provides instant feedback beyond what is possible in a traditional lab. This help students avoid learning (and unlearning) incorrect movement patterns.

Teacher-Student VR Telepresence with Networked Depth Camera Mesh and Heterogeneous Displays

We present a novel interface for a teacher guiding students immersed in virtual environments. Our approach uses heterogeneous displays, with a teacher using a large 2D monitor while multiple students use immersive head-mounted displays. The teacher is sensed by a depth camera (Kinect) to capture depth and color imagery, which are streamed to student stations to inject a realistic 3D mesh of the teacher into the environment. To support communication needed for an educational application, we introduce visual aids to help teachers point and to help them establish correct eye gaze for guiding students. The result allowed an expert guide in one city to guide users located in another city through a shared educational environment. We include substantial technical details on mesh streaming, rendering, and the interface, to help other researchers.

Virtual energy center for teaching alternative energy technologies

We overview the Virtual Energy Center, a VR environment that models a real energy facility to enable virtual field trips and self-guided exploration. Our goal is to take advantage of emerging low-cost hardware and improved networks to provide students who cannot travel to the real facility with alternatives that provide comparable educational benefit. The virtual facility is augmented by visual guides and educational content to teach students about concentrating solar power technology. A teacher physically near the student can appear in the scene via depth camera imagery, allowing the teacher to walk around in a classroom setting and assist students. Additionally, work-in-progress is streaming the depth images over a network to allow students to virtually meet expert guides from the real facility. We summarize these features, some interaction-related challenges, and ongoing testing.

Enhanced fuzzy-analytic hierarchy process

Application of fuzzy-analytic hierarchical process (fuzzy-AHP) has been growing continuously to select the best alternative. In the fuzzy-AHP approach, first the complex problem is itemized into a hierarchical structure for pairwise comparisons. Once a comparison matrix is formed, a triangular fuzzy number concept is adopted to assign priority weights with a view to capture the inherent vagueness in linguistic terms of the decision-maker. In evaluation, if two triangular fuzzy numbers are not intersecting

System Advisor Model (SAM) simulation modelling of a concentrating solar thermal power plant with comparison to actual performance data

({ t}_{11}- { t}_{23}\ge ~0)

Fuel Cell Integrated Energy System for Residential and Commercial Applications

(t11-t23≥0), then corresponding degree of possibility value is assumed to be zero (0). However, such situation simply represents the case of one criterion being immensely stronger than other and should not receive a zero value. In this regard, the article proposes an enhanced fuzzy-AHP approach where the triangles are extended about x-axis. This allows developing a mathematical formulation to estimate the true values of height of ordinate (degree of possibility). The empirical study of ranking the SECI modes in the order they influence the performance of the detailed design phase is considered to demonstrate the applicability and usefulness of the proposed framework. In order to measure the performance, five criteria are selected based on a rigorous literature review. After stringent experimentation, it is found that combination and externalization modes highly influence but other modes in order of internalization and socialization loosely have an effect on underlying phase.

Optimization of a low-gravity two-phase system for lunar heat rejection

Thermal control systems are essential to providing crew and equipment with an adequate thermal environment for space missions and outposts such as a lunar base. One concept for this is a reflux boiler system for lunar surface thermal control, in which heat is transferred from a thermal bus to vertical tubes and radiated to space. Several light-weight tube configurations have been built and tested by various manufacturers. This paper describes a mathematical model of such a device, including the performance of a single tube and a linear array of tubes. Model verification is demonstrated through correlation with NASA vacuum chamber test data. Following this, performance comparisons are made between three manufactured configurations of the tubes for similar environmental conditions and with the tube dimensions normalized with respect to one another, and conclusions are reached relative to the heat rejection capability of the three devices. Performance predictions for a linear array of tubes operating in a lunar surface environment are also presented.

Optimization of a low-gravity reflux boiler system for lunar surface thermal control

Abstract This paper is focused on the modelling and simulation of a 50 kW concentrated solar power (CSP) plant located in Crowley, Louisiana. The model was developed using system advisor model (SAM). The objective is to develop a predictive model (using SAM) to characterize the performance of the power plant and, thus, aid the analysis and evaluation of the plant’s performance. The power plant is a research facility of the Solar Thermal Applied Research and Testing (START) Lab. The model was validated by comparing its predictions with the actual plant data. The comparison showed a good correlation between the predicted results and the actual plant data. The validated model was then used to perform parametric analyses across different locations. The analyses showed that by operating the power plant at the optimal combination of solar multiple and hours of storage, we can achieve about 70% reduction in the cost of electrical energy.