Conference Session

Green Renewable Energy

Collection

2011 ASEE Annual Conference & Exposition

Authors

Deepak Gupta, Southeast Missouri State University; Ragu Athinarayanan, Southeast Missouri State University; Bradley J. Deken, Southeast Missouri State University

Tagged Divisions

Engineering Technology

sealevel rise, global temperature rise, warming oceans, shrinking ice sheets, declining arctic sea ice,glacial retreat, extreme events, and ocean acidification.1 To many, these reasons signal thatsignificant changes to the status quo are imminent.While these issues present challenges to our current way of life, they also provide a new outlookon the world and opportunities for careers and product development. Where there are challenges,there are also opportunities. The goal of this project was to train the next generation of workersto address these challenges. While jobs in the green economy were once rare, that is quicklychanging. Relatively few years ago there was no such thing as green building certifications,carbon cap and trading programs, and

Conference Session

NSF Grantees Poster Session

Collection

2011 ASEE Annual Conference & Exposition

Authors

David Jackson, VCU Haptics Lab; Dianne T.V. Pawluk, Virginia Commonwealth University; Curtis R. Taylor, University of Florida

Tagged Topics

NSF Grantees

. Page 22.495.1 c American Society for Engineering Education, 2011 Development of Haptic Virtual Reality Gaming Environments for Teaching Nanotechnology1. IntroductionNanotechnology is a key high technology field that is becoming increasingly important tothe United States’ economy. Maintaining leadership in key technologies, such asnanotechnology, is increasingly being recognized as important for Americancompetitiveness.1 There is, therefore, a strong interest in attracting K-12 andundergraduate students to pursue future careers in this area. However, the abstract natureof current learning methods of how things interact and behave at the nanoscale (< 100 nmin any dimension) can be

Conference Session

Topics Related to Telecommunications

Collection

2011 ASEE Annual Conference & Exposition

Authors

James O. Everly, University of Cincinnati; Xuefu Zhou, University of Cincinnati

Tagged Divisions

Engineering Technology

signal, third-order inter-modulation intercept point, and blockingdynamic range are measured with low-cost test equipment.An additional goal of the project is to prepare students for the upcoming Senior Design CapstoneExperience required for a baccalaureate degree in engineering technology. Students are requiredto maintain a detailed project journal to record test results, and experiences throughout theproject. To date, student feedback on this project has been very positive and a representativeselection of student comments is included in the paper.IntroductionAn objective of this paper is to introduce students to RF transceiver performance standards andtest procedures as described in the American Radio Relay League Performance Test Manual [1

Conference Session

NSF Grantees Poster Session

Collection

2011 ASEE Annual Conference & Exposition

Authors

Hirak C. Patangia, University of Arkansas, Little Rock

Tagged Topics

NSF Grantees

user and grid connectivity. Physics of panelsemiconductor will be left to other courses. Integration of our research finding from previous andcurrent work [1, 2] will be a major factor in the course design.Project Objectives Page 22.497.2The project focuses on four objectives: Proceedings of the 2011American Society for Engineering Education Annual Conference & Exposition Copyright © 2011 American Society for Engineering EducationObjective 1:Expand capacity of existing solar panels and establish a 2.5 KW PV test station with associatedinstrumentation. This will be completed within the first year of the

Conference Session

High School Engineering Programs, Curriculum, and Evaluation

Collection

2011 ASEE Annual Conference & Exposition

Authors

James C. Baygents, University of Arizona; Jeffrey B. Goldberg, University of Arizona; Jane Hunter, University of Arizona

Tagged Divisions

K-12 & Pre-College Engineering

educational outreach programs. The followingkey tasks were required for implementation: Page 22.498.6• Creating content – we had to take the content of the on-campus ENGR 102 course and put this in a format that is accessible to HS teachers. At the time the project was initiated, we did the following activities in our on-campus course: o The course is taught in a large main lecture format (1-time per week, professionalism) and a small section format (2-times per week, design process, teamwork). o 2 design projects – one project is a solar oven as it is especially interesting in the southwest as it dovetails with our efforts in

Conference Session

Capstone Design I

Collection

2011 ASEE Annual Conference & Exposition

Authors

Kevin M. Sevilla, Virginia Tech; Maura J. Borrego, Virginia Tech; Alexander Leonessa, Virginia Tech

Tagged Divisions

Design in Engineering Education

compared to the earlier andmore standardized phases of the project.References 1. McKenzie, L. J., Trevisan, M. S., Davis, D. C., & Beylerlein, S. W. (2004). Capstone design courses and assessment: A national study. Proceedings of the 2004 American Society of Engineering Education Annual Conference and Exposition, Salt Lake City, Utah. 2. Dym, C. L., Agogino, A. M., Eris, O., Frey, D. D., Leifer, L. J. (2005). Engineering design thinking, teaching, and learning. The Journal of Engineering Education, 94(1), 103-120. 3. Felder, R. M., & Brent, R. (2003). Designing and teaching courses to satisfy the ABET engineering criteria. The Journal of Engineering Education, 92(1), 7-25. 4. http

Conference Session

Lessons for New Engineering Educators

Collection

2011 ASEE Annual Conference & Exposition

Authors

John Marshall, University of Southern Maine

Tagged Divisions

New Engineering Educators

such, this document is divided into two major themes: active learning; andactive teaching.Topics included in the “Active Learning” section include: 1) Focusing on Learning and Not Page 22.500.3Teaching; 2) Problem Based Learning; 3) Facilitating Group Learning; 4) Changing LearningBehavior Outside the Classroom; and 5) Preparing to Teach. Topics included in the “ActiveTeaching” section include: 1) The Seven “Good Practices” for Teachers; 2) Teaching withHospitality; 3) The Importance of Listening; and 4) Assessment Via the Minute Paper.The presented pedagogical techniques are not cumbersome or extremely involved. In fact theyare fun and very

Conference Session

NSF Grantees Poster Session

Collection

2011 ASEE Annual Conference & Exposition

Authors

Tzu-Liang Bill Tseng, University of Texas, El Paso; Rong Pan, Arizona State University; Jun Zheng, University of Texas, El Paso; Carolyn Joy Awalt, University of Texas, El Paso, College of Education; Maria Veronica Gonzalez, University of Texas, El Paso; Francisco Medina

Tagged Topics

NSF Grantees

industry. More and more manufacturing companies in US aremoving out to oversea due to inexpensive labor cost and other resources. Manufacturingindustry becomes sensitive about cost effectiveness issues due to recent economic crisis.Manufacturing companies are cautious about sustainable workforce, particularly inequipment operation. The workers’ faulty operations could cause significant damage ofthe facilities and personal injuries and safety hazards. Moreover, through recent literaturesurvey, the fundamental challenging problem in manufacturing education: (1) How toimprove teaching and learning effectiveness in online course and facility training; (2)How to better educate students online facility training without interaction withinstructors1

Conference Session

Teaching Analog and Digital Communication: Novel Ideas for Lecture Courses, Laboratories, and Projects

Collection

2011 ASEE Annual Conference & Exposition

Authors

Alexander M. Wyglinski, Worcester Polytechnic Institute; Daniel J. Cullen

Tagged Divisions

Electrical and Computer

theoreticalbackground in digital communication systems, which can then be readily used in theimplementation of actual transmission systems based on SDR technology. In turn, theseimplementations will reinforce many of the concepts taught in class, as well as illustrate many ofthe non-ideal, realistic phenomena that occur during the transmission and reception of wirelessdata.Figure 1: Work flow of the senior undergraduate level digital communication systems course employing SDR experimentation. Page 22.502.6To overcome the significant learning curve that is often associated with the initial usage of SDRtechnology

Conference Session

ECE Division Poster Session

Collection

2011 ASEE Annual Conference & Exposition

Authors

Christopher S. Greene, University of Saint Thomas; Paul Ian Nyombi, University of Saint Thomas

Tagged Divisions

Electrical and Computer

require significant debugging time which, while valuable in the long run, divertsattention from the Signal and Systems concepts being taught. Analog Signal (voice/music) A/D SPI or Processing SPI or A/D I 2C I2C Analog Interface Interface Signal (Filtered) Figure 1 - "Preferred" configurationIn this paper we discuss a third alternative that has been developed, namely, to use the farsimpler (in

Conference Session

NSF Grantees Poster Session

Collection

2011 ASEE Annual Conference & Exposition

Authors

Nasser Alaraje, Michigan Technological University; Aleksandr Sergeyev, Michigan Technological University; Fred Scheu, College of Lake County

Tagged Topics

NSF Grantees

engineering technology 4-year programs among US academic institutions have acurriculum component in hardware description language and programmable logic design.Similarly, only 16.5% [3] of electrical and computer engineering technology 2-year programshave a curriculum component in hardware modeling and programmable logic design.The applications utilizing FPGA as a design medium are predominant [1]. FPGAs have been usedextensively not only in logic emulation but also in custom-computing machines. There-programmable nature of Static Random Access Memory (SRAM) -FPGA makes it theworkhorse of many new applications that require re-programmability. SRAM-FPGA’s are themost popular and are becoming the tools of choice in many re-programmable applications

Conference Session

Project-Based Learning

Collection

2011 ASEE Annual Conference & Exposition

Authors

Oscar G. Nespoli, University of Waterloo; Harry Tempelman, Hitachi Construction Truck Mfg Ltd.; Ryan Spencer; Steve Lambert, University of Waterloo

Tagged Divisions

Design in Engineering Education

provide feedback, in an actionable way, to our engineering curriculum and students’education. It represents their view on what is currently important to them. When soliciting inputfrom industry partners, there are often recommendations that they make that may or may not beimplemented in the curriculum. This mechanism and method represents an actionable and timelymethod to have the industry educational recommendations implemented.BackgroundThe process of education has been described as a two step process [1]; namely, the delivery ofknowledge, and the assimilation of knowledge by the learner. For engineering education, a thirdstep is required – the application of knowledge in uncertain situations and under constraint.Case studies continue to be

Conference Session

Best of Computers in Education Division

Collection

2011 ASEE Annual Conference & Exposition

Authors

Carole E. Goodson, University of Houston; Susan L. Miertschin, University of Houston; Barbara L. Stewart, University of Houston

Tagged Divisions

Computers in Education

(traditional lecture, online, and hybrid). The courses spanned subjects, with aresearch course, two consumer science courses, and two information technology courses. Thesurvey did not address issues related to the course through which the respondent was accessingthe survey, but rather, issues related to the student’s experience with on-line learning in general.The selection of courses served to provide a cross-section of students by level and major withvarying degrees of experience with online and hybrid modes of instruction. The survey wasadministered on-line and results were analyzed.This paper addresses the following issues. 1. Major frameworks for assessing on-line and distance courses are presented and summarized. The components examined

Conference Session

Distance and Web-based Learning in ECE

Collection

2011 ASEE Annual Conference & Exposition

Authors

Esteban Rodriguez-Marek, Eastern Washington University; Min-Sung Koh, Eastern Washington University; Claudio Talarico, Eastern Washington University; Jabulani Nyathi, Eastern Washington University

Tagged Divisions

Electrical and Computer

., should be made available.Coincidentally, a system of community colleges exists in the country that typically provides allstudents services and teaches most supporting classes needed by engineering degrees. Many ofthese community colleges have laboratories used both for vocational and pre-engineeringprograms. These laboratories tend to be well equipped and grossly underutilized [1]. A logicalconclusion, then, suggests itself: The resources available through the community college systemmust be coupled with those of four-year programs to offer engineering programs. The solutionhas three main advantages. First, universities offering 4-year engineering programs can reach astudent population previously outside of their geographical scope without

Conference Session

Design in Freshman and Sophomore Courses

Collection

2011 ASEE Annual Conference & Exposition

Authors

Ruth Wertz P.E., Purdue University, West Lafayette; Meagan C. Ross, Purdue University, West Lafayette; Michael Fosmire, Purdue University, West Lafayette; Monica E. Cardella, Purdue University, West Lafayette; Senay Purzer, Purdue University, West Lafayette

Tagged Divisions

Design in Engineering Education

becoming more complex. The problemsengineers encounter in the work force are ill-structured with constraints that extend beyond thereach of typical undergraduate engineering curricula, such as economic, social, political,environmental, and legal issues 1. To compound this problem, global economic competition,growing environmental concerns, and rapid technological advancement place additional demandson engineers to be more innovative in the solutions they create. There have been several reportsreleased in the last decade that call for engineers to become more skilled in communications,business, and economics, more creative and innovative, and more globally competent e.g. 2,3-6.Engineers must develop superior information literacy competencies, such

Conference Session

Graduate Student Experience

Collection

2011 ASEE Annual Conference & Exposition

Authors

Irene B. Mena, Purdue University, West Lafayette; Heidi A. Diefes-Dux, Purdue University, West Lafayette; Brenda Capobianco, Purdue University

Tagged Divisions

Graduate Studies, Student

course instructors, become members of the community of practice that is academia. This studywas guided by the following research questions: 1) What socialization experiences do doctoralengineering TAs report going through as a result of working as course instructors? 2) Whatrecommendations to improve the TA experience emerge from this study?Data were collected in the form of interviews (individual and focus group, with participants fromtwo schools of engineering at a Midwestern university). These data sources were analyzed andtriangulated to find recurring themes. Results indicated several categories of socializationexperiences, as characterized by the three TAs. Implications from the study suggest the need fora progressive TA model, in which

Conference Session

Engineering Ethics Issues Part One

Collection

2011 ASEE Annual Conference & Exposition

Authors

Michael Bowler, Michigan Technological University; Susan Amato-Henderson, Michigan Technological University; Thomas David Drummer, Michigan Technological University; Joanna M. Schreiber, Michigan Technological University; Joseph H. Holles, University of Wyoming; Ted W. Lockhart, Michigan Technological University; Jingfang Ren, Michigan Technological University

Tagged Divisions

Engineering Ethics

orientation more likely to increase that person’s ethical sensitivity to RCR.II. MethodsInstruments:Research Role Orientation InventoryPrevious research and pilot testing by our group led to the development and pilot testing of theResearch Role Orientation Inventory (RROI).11 The instrument, designed to assess a researcherssense of responsibility, authority, agency, autonomy, and duty, utilized a 6-point Likert-typescale requiring participants to rate their level of agreement (ranging from strongly disagree tostrongly agree) to 26 items designed to measure the role constructs (See Tables 1 and 2). Usinga factor analytic approach, the 26 items in the RROI included approximately 5 items found tomeasure each construct. Participants were instructed to

Conference Session

Factors Affecting Student Performance

Collection

2011 ASEE Annual Conference & Exposition

Authors

Maddumage Karunaratne, University of Pittsburgh, Johnstown

Tagged Divisions

Engineering Technology

wirings than on actual design or in optimizing the functions of the circuit. Evenafter HDLs such as VHDL have become standard and widely being used in commercial integratedcircuit chip making industry, undergraduate academic curriculums in Electrical and Computerengineering were very slow to adopt them[1] because of the cost of the hardware and associatedComputer Aided Design (CAD) tools coupled with lack of faculty experience on such design flowsrequired for digital designs.For many years, at college level courses that utilized HDL, the designs were limited to use them onlyfor design and simulation steps. Cost of programmable hardware development boards and associatedsoftware packages kept them away from most digital design courses. This

Conference Session

Student Learning and Assessment II

Collection

2011 ASEE Annual Conference & Exposition

Authors

Amir Karimi, University of Texas, San Antonio; Randall D. Manteufel, University of Texas, San Antonio

Tagged Divisions

Mechanical Engineering

are Torrentz, e-bay, Amazon.com, or CrAmster.com12-15.All required engineering, math, and science courses in the UTSA’s ME program must becompleted with a grade of C or better. The authors have observed that the percentage ofunsuccessful attempts to pass thermodynamics courses (grades of D, F, and W) increases whenstudents have access to the textbook solution manual. Table 1 shows grade distributions for twocourses in Thermodynamics taught by the same instructor. The number of students in eachcourse is identified by N. The table compares grade distribution in a course with low indicationsthat students had access to the textbook solution manual with that where a high percentage ofstudents were using textbook solution manuals to complete their

Conference Session

NSF Grantees Poster Session

Collection

2011 ASEE Annual Conference & Exposition

Authors

Ashley Baxter-Baines, Rowan University; Caitlin Nicole Dillard, Rowan University; Jennifer Vernengo, Rowan University; Stephanie Farrell, Rowan University

Tagged Topics

NSF Grantees

this experiment, freshman students produce drug-containing alginate spheres andinvestigate the factors which affect the rate of release of the drug from the polymericmicrospheres. (Technically the spheres produced are not microspheres since their diameter isabout 1-3 millimeters). The model drug used in this experiment is food coloring. Drug releasestudies are performed by placing the drug-loaded microspheres in a beaker containing water.Concentration measurements are made periodically by measuring absorbance of the surroundingsolution (into which dye has been released) using a spectrophotometer. The release rate of thedrug from the microspheres is analyzed using an Excel spreadsheet. The learning objectives ofthe experiment are: 1. Define a

Conference Session

Managing Dual-Career Issues

Collection

2011 ASEE Annual Conference & Exposition

Authors

Adrienne R. Minerick, Michigan Technological University; Beena Sukumaran, Rowan University; Jacqueline A. El-Sayed, Kettering University; Donna Reese, Mississippi State University; Brian P. Kirkmeyer, Miami University

Tagged Divisions

Women in Engineering

New Mexico State University3 havetried programs that provide some financial support for departments hiring spouses of facultycandidates. They found this to be unsustainable and now have programs similar to thosementioned above. Other schools, like University of Michigan4 have based their programs out ofthe provost’s office rather than Human Resources and provide support at that level to work withdepartment chairs wanting to accommodate dual-career couples. They also provide resources fordepartment chairs and faculty search committees that help answer commonly asked questions onthis process.Table 1: Panelist and Spouses. Panelist will be at the session, but in all cases, spouses are notexpecting to attend.A Beena Sukumaran, Ph.D

Conference Session

NSF Grantees Poster Session

Collection

2011 ASEE Annual Conference & Exposition

Authors

Richard Chiou, Drexel University; Michael G. Mauk, Drexel University; Robin Kizirian, Drexel University; William Peeples, Drexel University

Tagged Topics

NSF Grantees

 Acquisition  Acquired and  Apply SoftSensor  parameters  Image  processed images  Blob Analysis  Data Output  Decision making  Quality  Control  Figure 1: Solar cell vision system processing flow chart Page 22.515.4Figure 1 displays the flow diagram for the processing procedure of a vision system. The visionsystem is comprised of a smart

Conference Session

Persistence and Retention I

Collection

2011 ASEE Annual Conference & Exposition

Authors

Tiffany Tseng, Stanford University; Helen L. Chen, Stanford University; Sheri Sheppard, P.E., Stanford University

Tagged Divisions

Educational Research and Methods

identifying the factors that influence academic persistence haveemployed a range of cross-sectional and longitudinal research designs and qualitative andquantitative methodologies. Seymour and Hewitt (1997) interviewed over 300 juniors andseniors at seven institutions to understand their reasons for switching to majors outside of Page 22.516.2science, mathematics, or engineering (SME)3. Significant factors included a loss of interest in 1/22science and being overwhelmed by curriculum demands. Comparisons between the studentswho switched and those who stayed in SME majors revealed differences in

Conference Session

Engineering Education Research in K-12

Collection

2011 ASEE Annual Conference & Exposition

Authors

Karen A. High, Oklahoma State University; Melanie C. Page, Oklahoma State University; Julie Thomas, Oklahoma State University

Tagged Divisions

Educational Research and Methods, K-12 & Pre-College Engineering

’ parents to create mathpromotive environments for them.14 Elementary teachers are generally known to exhibit lowscience/math confidence – suggesting they have bought into the idea that science andmathematics are for boys.16 These teachers’ gender schemas subtly influence children’s STEMachievement.17 Elementary teachers may also not recognize the need or have the training toconnect STEM subjects to Native language and cultural traditions.18Young girls begin to form definite ideas about their personal science and math interests andabilities during their elementary school years. These early ideas (1) influence later decisionsabout science and math achievement in middle school and high school and (2 exacerbate theSTEM workforce pipeline problem. The

Conference Session

Engineering Mathematical Potpourri

Collection

2011 ASEE Annual Conference & Exposition

Authors

John Schmeelk, Virginia Commonwealth University, Qatar

Tagged Divisions

Mathematics

ProcessingAbstract Image edge detection is an integral component of image processing to enhancethe clarity of edges and the type of edges. Issues regarding edge techniques wereintroduced in my 2008 paper on Transforms, Filters and Edge Detectors.15 The currentpaper provides a deeper analysis regarding image edge detection using matrices; partialderivatives; convolutions; and the software MATLAB 7.9.0 and the MATLAB ImageProcessing Toolbox 6.4. Edge detection has applications in all areas of research,including medical research6,16. For example, a patient can be diagnosed with ananeurysm by studying the shape of the edges in an angiogram. An angiogram is thevisual view of the blood vessels (see Figure 1-Vascular Web image). The previouspaper15 studied

Conference Session

Active and Inquiry-Based Learning

Collection

2011 ASEE Annual Conference & Exposition

Authors

David B. Knight, Pennsylvania State University, University Park

Tagged Divisions

Educational Research and Methods

(Figure 1) is a subsection of a larger modelby Terenzini and Reason36,37, which conceptually combines factors that form the “UndergraduateExperience” in an effort to explain student learning outcomes and persistence and bring overallcoherence to research examining the effects of college on student development (Figure 1). TheTerenzini and Reason36,37 model has undergone several iterations in studies of engineeringeducation to produce a systems view of undergraduate learning that 1) addresses the role ofstudents’ characteristics and prior experiences, and 2) considers the influence of organizationalconditions (e.g., policies affecting classroom-level practices), program-level faculty culture, andprogram policies and practices related to teaching

Conference Session

Certifying Teachers in Engineering or Integrated STEM

Collection

2011 ASEE Annual Conference & Exposition

Authors

Yvonne Ng, St. Catherine University; Lori R. Maxfield, Saint Catherine University

Tagged Divisions

K-12 & Pre-College Engineering

or non-existent.This paper presents 1) how a basic introduction to engineering course designedfor general education and potential engineering majors was deliberately improvedusing the Parallel Curriculum Model (PCM) to align with eight ABET ProgramOutcomes found in Criterion 3; 2) how PCM was also used to carefully structurethe curriculum to meet the needs of multiple learners (general education students,pre-engineering students, elementary education students); 3) how we structuredthe learning activities and assignments to assess student competence, confidenceand comfort (“the 3C’s”) with engineering, and 4) how the team teaching modelthat includes an engineering and education faculty member provides enhancedopportunities to use innovative

Conference Session

Globalizing Engineering Education II: Best Practices

Collection

2011 ASEE Annual Conference & Exposition

Authors

James McConnell, North Carolina State University; Brian D. Koehler, North Carolina State University

Tagged Topics

ASEE Global Programs

in another culture. 1 The effects are felt long after return.Ninety-five percent of “alumni” report that their international experience had a lasting impact ontheir world view and a majority said that it influenced their career path. Although the number ofstudents enrolled in international study has doubled over the past decade, only a small percent ofundergraduates nation-wide take advantage of this opportunity. 2 At NC State University almost30% of all enrolled international students are in the College of Engineering, however, a muchsmaller fraction of students participate in international study. Page 22.521.21 U.S. Committee for

Conference Session

Design Education II

Collection

2011 ASEE Annual Conference & Exposition

Authors

Ronald J. Bennett, Univeristy of Saint Thomas; Elaine R. Millam, Univeristy of Saint Thomas

Tagged Divisions

Manufacturing

education, training and on-site programs beyond production methodsthat include content covering leadership. They can help leaders develop the characteristicsneeded to create the environment for the employees to become more innovative and see their rolein the larger systems context. This has been the objective of the Society of ManufacturingEngineers and the program specific curriculum criteria they have established for EngineeringAccreditation Commission (EAC) of ABET accredited manufacturing engineering programs.1ABET Manufacturing CriteriaThe Engineering Accreditation Commission (EAC) of ABET program criteria formanufacturing1 requires that programs demonstrate that graduates have proficiencies in fivespecific areas: 1) materials and

Conference Session

Energy Education and Industrial Partnership Needs

Collection

2011 ASEE Annual Conference & Exposition

Authors

Patrick A. Tebbe, Minnesota State University, Mankato

Tagged Divisions

Energy Conversion and Conservation

recently when largescale public discussion of energy use in buildings has emerged. However, energy use inbuildings is quite large. For 2009, a total of 41% of total energy consumption in the U.S. went toresidences and commercial sectors whereas only 29% went to transportation.1 “On an annual basis, buildings in the United States consume 39% of America's energy and 68% of its electricity. Furthermore, buildings emit 38% of the carbon dioxide (the primary greenhouse gas associated with climate change), 49% of the sulfur dioxide, and 25% of the nitrogen oxides found in the air.”2According to a study by the U.S. Department of Energy, “the total cooling energy use incommercial building HVAC systems, including the refrigerant