Using Remote Access for Sharing Experiences in a Machine Design Laboratory

A new Machine Design Laboratory at Marquette University has been created to foster student exploration and promote “hands-on” and “minds-on” learning. Laboratory experiments have been developed to give students practical experiences and expose them to physical hardware, actual tools, and design challenges. Students face a range of real-world tasks: identify and select components, measure parameters (dimensions, speed, force), distinguish between normal and used (worn) components and between proper and abnormal behavior, reverse engineer systems, and justify design choices. The experiments serve to motivate the theory, spark interest, and promote discovery learning in the subject of machine design. This paper presents details of the experiments in the Machine Design Laboratory and then explores the feasibility of sharing some of the experiences with students at other institutions through remote access technologies. The paper proposes steps towards achieving this goal and raises issues to be addressed for a pilot-study offering machine design experiences to students globally who have access to the internet

Freehand Sketching for Engineers: A Pilot Study

This paper describes a pilot study to evaluate Freehand Sketching for Engineers, a one credit, five week course taught to undergraduate engineering students. The short-term goal of this course was to improve engineering students’ freehand sketching ability and to assess their progress with metrics. The long-term objective (desired learning outcome) of this course is to improve the creativity and innovation of student design projects by enhancing students’ ability to visualize their ideas with freehand sketches. The class met two days a week for 75 min per day. Students were taught to draw simple objects such as electrical boxes, with orthographic, isometric, and oblique views on 8 ½ x 11 in. sheets of blank paper (no grid lines) and wooden #2 pencils. No instruments, such as rulers and compasses, were allowed. The course required students to apply what they learned in the classroom and included many examples of hands-on, active and student-centered learning activities. Two assessments were performed to measure whether students improved their ability to freehand sketch. The first involved two outside reviewers (industrial designers) who evaluated each student’s sketch of a pipe fitting that was drawn in the first class (pre-test) and a sketch of the same pipe fitting in the eighth class (after 7 hours of instruction - post-test). Sketches were evaluated using a 1 (poor) to 7 (excellent) Likert scale. The second assessment consisted of an evaluation of the final projects, which were a collection of five sketches with different views of an engineered product. Evaluations of the pre- and post-test drawings and the final projects by outside reviewers and positive observations by engineering faculty suggest that this course has the potential to improve students’ ability to sketch objects. This paper discusses details of the course, provides examples of student sketches, and presents results of outside reviewer assessments. It includes suggestions for a more rigorous assessment of the course to determine its potential to improve students’ ability to sketch objects

Aquaponics: A Sustainable Food Production System That Provides Research Projects for Undergraduate Engineering Students

Aquaponics is a closed-loop, recirculating water system in which plants and fish grow together mutualistically. Aquaponics resembles a natural river or lake basin in which fish waste serves as nutrients for the plants, which in turn clean the water for the fish. Tilapia and salad greens or herbs are common fish and plants grown in an aquaponics system. The external inputs to an aquaponics system are fish food, minimal amount of water, and energy for lighting and heating the water for the fish and plants. Aquaponics is a sustainable, efficient system to raise fish protein and vegetables for human consumption. Aquaponics systems can be located anywhere in the world where there is adequate energy with a minimal amount of water. Aquaponics is particularly suited to arid climates because it uses much less water to grow plants than soil-based systems. In fact, the only water that is lost is evaporation and transpiration from the plants. Although the field of aquaponics is growing world-wide, the capital and operational costs of producing the plants and fish have not been quantified intensively in the peer-reviewed literature. The relationship between the amount of external energy (fish food plus energy for light and heat) to the output (weight of fish and plants) has not been measured well for aquaponics units in temperate climates. The lack of quantification of the input-output has suppressed aquaponics progress because it is difficult to compare the cost of fish and salad greens grown with aquaponics and conventional methods, such as aquaculture and soil-based methods. The diverse nature of aquaponics and the need to quantify the relationship between input-output presents opportunities for research projects for undergraduate engineering students in Mechanical, Electrical, and Civil Engineering. The following are examples: Sensors: What type of sensors are ideal to measure air and water temperature, water PH, dissolved O2, and nitrates? Thermodynamics: What type of water heating system is most efficient to maintain desirable water and air temperature? Water Quality: What are the optimal methods to filter out the solid fish waste (feces) and introduce necessary bacteria into the system? Hydraulics: What size of pump and diameter of pipe are needed to maintain optimal flow rate? System Design: What are the optimal ratios between fish tank volume and grow area volume? What is the optimal drop in water level between components to utilize the gravity system? Marquette University College of Engineering is building a laboratory to conduct aquaponics research. The design of the system along with the lessons learned will be presented, along with a detailed list of specific projects for engineering students. Lessons learned from this research will aid the development of aquaponics in temperate climates but also possibly in subtropical and tropical region

Communicating the Value of Ergonomics to Management – Part 2: Ergonomics ROI Case Study Applications

More than ever, human factors engineers and ergonomists need to justify our practice’s value to management. How can we effectively communicate with management? How should we present a Return on Investment (ROI) that leadership will find useful that addresses company profits, cost savings, productivity, first time quality, and turnover? What else does management care about other than ROI? This second panel in a two panel series will specifically highlight case studies in which presenters give examples of situations in which ROI for ergonomics was investigated from a business value. The session will start with four case study lectures followed by a panel discussion led by the moderators. The audience will be encouraged to participate with their own questions and comments

Applied Force and sEMG Muscle Activity Required To Operate Pistol Grip Control in an Electric Utility Aerial Bucket

Electric utility line workers report high levels of fatigue in forearm muscles when operating a conventional pistol grip control in aerial buckets. This study measured the applied force and surface electromyographic (sEMG) signals from four upper extremity muscles required to operate the pistol grip control in two tasks. The first task was movement of the pistol grip in six directions (up/down, forward/rearward, clockwise/counter-clockwise), and the second task was movement of the bucket from its resting position on the truck bed to an overhead conductor on top of a 40 ft tall pole. The force applied to the pistol grip was measured in 14 aerial bucket trucks, and sEMG activity was measured on eight apprentice line workers. The applied force required to move the pistol grip control in the six directions ranged from 12 to 15 lb. The sEMG activity in the extensor digitorum communis (EDC) forearm muscle was approximately twice as great or more than the other three muscles (flexor digitorum superficialis, triceps, and biceps). Line workers exerted 14 to 30% MVCEMG to move the pistol grip in the six directions. Average %MVCEMG of the EDC to move the bucket from the truck platform to an overhead line ranged from 26 to 30% across the four phases of the task. The sEMG findings from this study provide physiologic evidence to support the anecdotal reports of muscle fatigue from line workers after using the pistol grip control for repeated, long durations

Incorporating Freehand Sketches and Mockups into Senior Design Capstone Course: Case Study with a Hand Cycle Vehicle Rack

From the students’ perspective, the project objective of this 2-semester senior design course was to design and build a storage device for a hand powered upright hand cycle that can be installed on the exterior of a wheelchair accessible Dodge-Chrysler minivan so that a person with paraplegia or quadriplegia can drive the vehicle independently (without a human aide) when the hand cycle is loaded on the vehicle. The novelty of this paper is the pedagogy of blending traditional methods of engineering design (hand sketches, low resolution mockups, and prototypes) along with CAD design and modern computational analytics, including FEA, in a 2-semester design course. Students drew sketches of multiple ideas and made a full-size three dimensional mockup of the rear of a Chrysler minivan out of plywood and structural wood. They also made two mockups and two metal prototypes and analyzed the design with FEA. Course evaluations from students revealed their appreciation for having the opportunity to hand sketch ideas and make low resolution mockups in the first semester to arrive at a general design. (The second semester was devoted to detailed design and making functional prototypes.) The students felt that they had a rich design experience that they could use for future design projects in their careers

Are Posture Data from Simulated Tasks Representative of Field Conditions? Case Study for Overhead Electric Utility Workers

Many ergonomics studies are conducted in laboratory-simulated work environments to assess risks for the development of musculoskeletal disorders under more controlled conditions. However, the simulated conditions could be of questionable validity with respect to reproduction of field conditions involving risk factors. The objective of this study was to verify whether the postures recorded for neck extension/flexion and upper arm elevation of overhead electric utility workers in a simulated environment were similar to those recorded in a field environment. Of the three frequently performed tasks analysed, two presented similar exposure in both conditions. However, differences were identified for a more complex task (relay replacement). These results suggest that simulated tasks may be more representative for more standardised tasks. This may indicate that researchers investigating risks should avoid simplifying complex tasks when reproducing field posture exposure in laboratories, since omitting extra subtasks may lead to an inaccurate reproduction of field exposure. Practitioner Summary: Studies comparing results from field and simulated environments are necessary to evaluate to what degree postural exposure reproduced in laboratory is representative of the exposure occurring in real work situations. This is particularly relevant for tasks involving training in simulated environment due to safety constraints

Measurement of Stiffness and Damping Characteristics of Computer Keyboard Keys

To determine the stiffness and damping of computer keyboard keys, a computer-controlled test rig that can measure computer key displacement, velocity, and contact force has been designed. The test rig, consisting of a single-axis stage carrying a probe for contacting keys, has been used to collect contact force and motion data as computer keys are depressed and released at constant velocities up to 80mm∕s . Keys that employ a rubber-dome under their caps to achieve the necessary compliance and toggling action were tested. The results demonstrate a nonlinear stiffness force versus displacement characteristic at a given speed and the presence of damping-type forces that increase with key depression speed at a given displacement. In particular, the results indicate that the peak force at the 80mm∕s rate of depression increases relative to the quasistatic (0.5mm∕s) force level by over 12% for the “Enter,” “K,” and “Spacebar” keys. This paper describes the hardware and software configuration, and presents sample results of the stiffness and damping characteristics of keys during depression-return stroke tests

Effect of Two Common Head-Mounted Augmented Reality Systems on Muscle Force and Blink Rate of Electric Utility Power Plant Operators

Augmented reality (AR) is a technology that combines real and virtual information presented to the user in an interactive way in real time. The Microsoft HoloLens and RealWear HMT-1 are two common types of head-mounted AR available to industrial field workers. These two AR systems were tested on how they affected blink rate, an indicator of eye strain, and electromyographic (sEMG) activity of the neck and shoulder muscles of electric utility power plant operators while they performed five routine inspection tasks of coal equipment. The inspection tasks were conducted under three conditions: HoloLens, HMT-1, and No AR (regular method). Workers communicated with the HoloLens with a right-hand gesture and by voice input to the HMT-1. The duration of the inspection tasks ranged from an average of 10 to 28 sec. Twelve experienced power plant operators participated in the study. sEMG) of the right and left sternocleidomastoid, splenius, semispinalis capitis, and upper trapezius muscles were measured, and a small camera recorded blink rate of the right eye. Results reveal generally no significant differences in 50th and 90th percentile sEMG between the three conditions for all eight muscles. Although the means of blink rate appeared consistently lower with the HoloLens than the No AR and HMT-1 (approximately 4.4 blinks/min), these differences were not significant at the 0.05 level (p=0.06 to 0.17). Future studies should investigate a larger sample size of workers wearing AR devices for longer time periods (\u3e 30 min) to determine long-term effects of AR devices on muscle activity and eye strain. A system of hardware, software, and experimental protocol was developed that follow-up studies may employ to test physiological effects of AR devices