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Conference Session
Environmental Engineering Division Technical Session 3
Collection
2018 ASEE Annual Conference & Exposition
Authors
Bettina Jeanine Casad, University of Missouri, St. Louis; Monica Palomo P.E., California State Polytechnic University, Pomona; Natalie Mladenov, San Diego State University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
wasacceptable at both time points (T1 α = .715, T2 α = .91). Items were averaged so that higherscores indicated greater confidence in abilities to work in teams.Education intentions. Three questions (Estrada et al., 2011) assessed participants’ educationplans in engineering. Questions were answered on a scale from 1 (Very unlikely) to 6 (Verylikely) indicating students’ plans to attend an MS program in engineering, a PhD program, and togain experience working in an engineering lab. Items were averaged such that higher scoresrepresented greater intentions to pursue additional education and were analyzed individually.Career intentions. A 7-item measure (Estrada et al., 2011; Schultz & Estrada, 2010) evaluatedstudents’ career intentions in the field
Conference Session
Environmental Engineering Division Technical Session 3
Collection
2017 ASEE Annual Conference & Exposition
Authors
Inez Hua, Purdue University; Loring Nies, Purdue University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
. The impact of these education programs can be measured in terms of studentparticipation in EE major programs, student diversity, and learning outcomes related toenvironmental sustainability.Environmental and Engineering at Purdue University The BS degree in Environmental and Ecological Engineering (EEE) received final approvalfrom the Indiana Commisson of Higher Education on September 14, 2012 and ABETaccreditation in 2013, retroactive to October 2012. This marked the end of an almost decade-longprocess of program planning and launch. The foundation of the EEE program was built through an NSF Curricular Planning grantawarded in 2002: “The Future Role of Ecological Engineering Science in UndergraduateEngineering Education.” The Purdue
Conference Session
Sustainability and Hands-on Engineering Education
Collection
2015 ASEE Annual Conference & Exposition
Authors
Rachel A Brennan P.E., Pennsylvania State University, University Park
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
student outreach organization (EWB)to mobilize the resulting efforts to engage developing coastal communities with the assistance ofpracticing engineers. The longevity of this program is supported through cross-disciplinaryresearch, course development, and mentoring of EWB projects containing interdisciplinary,multi-component systems. Future partnerships in the areas of wind energy, coral reef resilience,food systems science, economic development, and eco-tourism are planned to further enhancethe program. Page 26.75.2IntroductionCurrently 2.5 billion people, over one third of the Earth’s population, are affected by waterscarcity and are without
Conference Session
A Focus on Sustainability
Collection
2020 ASEE Virtual Annual Conference Content Access
Authors
Anand Raj, University of Texas at El Paso; Peter Golding, University of Texas at El Paso; Diane Elisa Golding, University of Texas at El Paso; Scott A. Starks, University of Texas at El Paso; Luis Rene Contreras Sapien, University of Texas at El Paso; Suzan Aranda Luna, University of Texas at El Paso
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
Paper ID #30947Study of the Impact of the University on Sustainability in Far West TexasMr. Anand Raj, The University of Texas at El Paso Anand Raj is a Doctoral student in the Environmental Science and Engineering Program at The University of Texas at El Paso. His doctoral studies focus on sustainability in higher education. His interest lies in the three pillars of sustainability which include social, environmental, and economic aspects. He has a master’s degree in business with industry experience. His future plan is to use his business experience to promote sustainability which is important in today’s world.Dr
Conference Session
Environmental Engineering Division Technical Session 1: Intercultural Competency-infused Teaching
Collection
2021 ASEE Virtual Annual Conference Content Access
Authors
Jane Lu Hsu, National Chung Hsing University, Taiwan; Yu-Kang Lai, National Chung Hsing University, Taiwan; Tzu-An Tzeng, National Chung Hsing University, Taiwan; Yi-Hsuan Yu, National Chung Hsing University, Taiwan
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
much research has shown that environmental knowledge does not directly lead topro-environmental behaviors, environmental knowledge can enhance people’s capability anddrive their motivation to perform pro-environmental behaviors [19].2.2.2 Environmental Behavior The theory of planned behavior has been widely used in different fields to understandpeople’s behaviors [20]. In the theory of planned behavior, the individual’s intention decideswhether or not they engage in a behavior or not [21]. Intention is influenced by three factors:attitude toward the behavior, subjective norms, and perceived behavioral control [22]. Perceivedbehavioral control represents an individual’s perception of the ability to control the requiredresources and
Conference Session
Environmental Engineering Technical Session 4: Environmental Issues and the Impacts of Intersectionality
Collection
2021 ASEE Virtual Annual Conference Content Access
Authors
Angela R. Bielefeldt, University of Colorado Boulder; JoAnn Silverstein P.E., University of Colorado Boulder
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering, Women in Engineering
that they showed the community plans of one highway that was still affecting them but went with another design. She described how often the initial plan was not exactly what they were going to follow through with.” 4. Act as faithful agent 10 [frequently misinterpreted the meaning on conflict of interest as conflicting interests among different groups in Tampa – e.g. commuters vs. locals] 5. Reputation by merit 0 6. Uphold professional
Conference Session
Environmental Engineering Division Technical Session 3
Collection
2019 ASEE Annual Conference & Exposition
Authors
Sanjay Tewari, Missouri University of Science & Technology
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
asked to choose a category to identify themselves in the context oftheir learning styles. The details of the survey are provided in the results and discussionsection.4.0 MethodologyAt the start of the semester, students were not informed about the author's plan to collect thedata for this study. Students were assigned many out-of-class assignments over the durationof the semester as a part of the course activities. They were assigned with a good mix ofrequired and optional (extra) assignments. The author included a wide variety of assignmentssuch as videos, audios, news articles, textbook reading, search-it-yourself assignments oncertain topics, and certain USEPA/USGS webpages. The textbook assignments weresometimes assigned as a specific sub
Conference Session
Inventive Opportunities for Research and Exposure
Collection
2020 ASEE Virtual Annual Conference Content Access
Authors
Pamela McLeod, ReNUWIt at Stanford University; Junko Munakata Marr, Colorado School of Mines; Richard G. Luthy, Stanford University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
) to increase undergraduate students’ interests in pursuing advanceddegrees in water science/engineering, with a particular emphasis on women and minorities.In addition to the program-level objectives, we identified five student-level outcomes thatprovide a framework for the assessment plan. We proposed that through participating in thisREU, students would: (S1) conduct independent research in water science or engineering; (S2)gain an understanding of urban water infrastructure challenges and the ERC’s systems-levelapproach; (S3) experience the enthusiasm and passion our ERC research team has for waterscience and engineering; (S4) express increased interest in pursuing graduate degrees inengineering and science; (S5) demonstrate increased
Conference Session
Environmental Engineering Division Technical Session 2
Collection
2019 ASEE Annual Conference & Exposition
Authors
Alan S. Hoback, University of Detroit Mercy; Alexa Rihana Abdallah, University of Detroit Mercy
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
township, county and state level.The Occupational Safety and Health Administration (OSHA) is responsible for monitoringworking conditions in the United States. OSHA has authority to inspect any place of work at anytime, but twenty-six states have approved plans. This means that OSHA has delegated authorityto them. OSHA directly runs the program in the other states [6]. OSHA plans inspections usingthree processes. First, programmed inspections are those that happen frequently because theindustry is hazardous. Second, complaint inspections are responses to worker(s) complainingabout working conditions. Third, referral inspections are responses to health inspectors referringissues to OSHA. Although inspections are rare at manufacturing establishments
Conference Session
Environmental Engineering Division Technical Session 3
Collection
2018 ASEE Annual Conference & Exposition
Authors
Andrew Ross Pfluger, Colorado School of Mines; Junko Munakata Marr, Colorado School of Mines; Gary Vanzin; Robert L. Siegrist, Colorado School of Mines
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
ofthe most commonly used approaches for term weighting (Aizawa, 2003) and is describedfurther in Section 4. Such term frequency analyses have been used in numerouseducational contexts, from examination of Master’s thesis and PhD dissertations toidentify common topics (Rivera & Larrondo-Petrie, 2017), to engineering term languagegaps between professors and students in freshman-level engineering courses as a barrierto learning (Variawa et al., 2013; Variawa & McCahan, 2012).2. Course Description and Student DemographicsOur university’s onsite course focuses on the selection, design, and implementation ofdecentralized systems for water reclamation and reuse. Topics include process analysisand system planning, engineered and natural system
Conference Session
Environmental Engineering Division Technical Session 1
Collection
2019 ASEE Annual Conference & Exposition
Authors
Sharanabasaweshwara Asundi, Old Dominion University; Gregory C. Bernard, Tuskegee University; Willard E. Collier, Tuskegee University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
alone were a $7.5 billion market in the United States in 2016 (Smithet al. 2017). Traditional herbal medicine is a repository of knowledge regarding natural productswith medicinal properties (Miller and Su 2011). Availability of the required medicinal plants andtheir purity are rapidly becoming issues throughout the world. The looming antibiotic resistancecrisis is an excellent example of the need for MSPC research to produce new antibiotic molecules.A research-based education program, like iREP-4-PACE, to identify new antibiotics frommedicinal plants and then produce them using MSPC affords an excellent platform to train studentsin essential skills that can be applied to their career paths.3. Plan of Operation and MethodologyThe complete
Conference Session
A Focus on Sustainability
Collection
2020 ASEE Virtual Annual Conference Content Access
Authors
Azadeh Bolhari P.E., Angelo State University; Daniel Ivan Castaneda, James Madison University; Kenneth Stewart, Angelo State University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
funded by the National Science Foundation Award # 1744006. The authors aregrateful to the help provided by the following research students at Angelo State University: JesseLee, Maria Ochoa, Austin Poole, Nicholas Manrique and Timmons (TJ) Spies.References[1] ODPM, 2004. The Egan Review: skills for sustainable communities. London: Office of theDeputy Prime Minister.[2] AlWaer, H., R. Bickerton, and R. D. Kirk. 2014. Examining the Components Required forAssessing the Sustainability of Communities in the UK. J Archit Plann Res. 31 (1): 1–26.[3] Male, S. A. 2010. Generic Engineering Competencies: A Review and Modelling Approach.Education Research and Perspectives, 37(1), 25-51.[4] Ritchie, H., Sheppard, A., Croft, N., Peel, D. 2017. Planning
Conference Session
Enviromental Engineering Division Poster Session
Collection
2015 ASEE Annual Conference & Exposition
Authors
Veera Gnaneswar Gude P.E., Mississippi State University; Dennis D. Truax PE, BCEE, F.ASCE, Mississippi State University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
works facilities to provide students with the opportunity to view equipment and operations. Site visit reports complying with the provided format were due one week after the visit is conducted. A final exam was conducted during the last week of the semester. The exam was administered online and may be taken at the individual students’ schedule.Student ExperiencesThe water treatment (coagulation-flocculation-sedimentation-filtration) experiments wereconducted using actual water samples from two algae contaminated ponds. The students wereasked to prepare the samples and plan the experimental procedures to determine the optimum Page
Conference Session
Environmental Engineering Division Technical Session 1
Collection
2018 ASEE Annual Conference & Exposition
Authors
Fethiye Ozis P.E., Northern Arizona University; Sahar Razavi, Northern Arizona University; Nihal Sarikaya, Northern Arizona University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
the United States, would be a cheap, viable resource touse in the remediation of heavy metals in water [45]. Melissa saw that there has been littleresearch into corn as a bio-sorbent for heavy metal, and saw the potential of it being used as anadsorbent. Thus, she proposed testing corn cobs for their effectiveness at removing Cadmiumfrom water.The proposal was approved by the NASA Space Grant Committee at NAU and Melissa startedworking on her research. While our study focuses on just one student, her situation is applicableto many others, who are more than likely experiencing similar struggles.Melissa has been meeting with her mentor once, every two weeks to discuss the plan. Mentorand mentee came up with a tentative schedule, plan for
Conference Session
Environmental Engineering Technical Session 4: Environmental Issues and the Impacts of Intersectionality
Collection
2021 ASEE Virtual Annual Conference Content Access
Authors
Shannon Katherine Gilmartin, Stanford University; Angela Harris, North Carolina State University; Christina Martin-Ebosele, Stanford University; Sheri Sheppard, Stanford University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering, Women in Engineering
these results might prompt new thinking about undergraduateengineering education and environmental work. We consider how our findings can informteaching and learning for effective early career practice and future leadership. We proposeleadership modules in environmental engineering curricula that focus on not only the urgentenvironmental problem space, but gender and racial equality in the people space surrounding it.1.0 IntroductionUnderstanding the school-to-work pathways of engineering students—intentions and plans priorto graduation, destinations and experiences after graduation—is a critical component ofintegrated, effective educational practice. Educational settings are not isolated entities in whichlearning communities intuit relevance
Conference Session
Environmental Engineering Division Technical Session 2
Collection
2018 ASEE Annual Conference & Exposition
Authors
Angela R. Bielefeldt, University of Colorado, Boulder; Greg Rulifson P.E., Colorado School of Mines
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
environmental issues in particular. This method therefore avoids bias in the studentresponses, since leading questions were not posed. The interview questions asked students whatthey had been doing the previous year in courses, outside of classes, and summer internships.The interviews also asked questions about students’ views of social responsibility and futurecareer plans. The interviews were transcribed. Emergent themes related to the research questionsaround environmental issues were identified in the interview transcripts. The themes werediscussed by the two authors to establish convergent opinions.The relevant context of environmental opportunities at each of the three institutions initiallyattended by the environmentally-motivated students in
Conference Session
Environmental Engineering Division: Sustainability and Hands-On Engineering Education
Collection
2016 ASEE Annual Conference & Exposition
Authors
Paula Alvarez Pino, UAB Sustainable Smart Cities Research Center; Andrew J. Sullivan; Fouad H. Fouad, University of Alabama - Birmingham
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
where theylearn the basic construction process of the green roof, its function, types of plants, and energysavings of the building. A tour of the university library is also provided, in which proper literaturereview processes are introduced and how to effectively use databases.Figure 4 – Laboratory toursThe Summer Enrichment Program has been offered during the past three summers. Enrollmenthas steadily increased with each offering. Students are asked to provide a testimonial at the end ofthe program describing their experiences, what they learned, which activity had the most impact,and their plan for the future. Example statements that stand-out include:“I learned the ethics of engineering and the proper way to gain knowledge in order
Conference Session
Enviromental Engineering Division Poster Session
Collection
2015 ASEE Annual Conference & Exposition
Authors
Araceli Martinez Ortiz, Texas State University, San Marcos; Bahram Asiabanpour, Texas State University; Semih Aslan, Texas State University, San Marcos; Jesus Alejandro Jimenez, Texas State University; Yoo-Jae Kim, Texas State University; Hassan Salamy, Texas State University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
pipeline” with the goals of increasing students’ early interest in STEMcareers, enhancing student academic and professional preparation in the green energy industryand increasing retention rates in undergraduate STEM courses. The SMART team set a plan todevelop and deploy a series of outreach programs and a university green learning and discoverymodel to connect with a broader range of students from middle school, high school, communitycollege to undergraduate/graduate students by 1) moving beyond traditional STEM topicsthrough the exciting themes of green energy and environmentally friendly designs, 2) exposingstudents to careers in the green energy industry, 3) emphasizing the social and moral impact ofscientists and engineers involved in the
Conference Session
Inventive Opportunities for Research and Exposure
Collection
2020 ASEE Virtual Annual Conference Content Access
Authors
Inez Hua, Purdue University, West Lafayette; Loring Nies, Purdue University, West Lafayette; Lindsey B. Payne, Purdue University, West Lafayette
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
, including a foundational course required forall students. During an EEE faculty retreat in May 2015, the faculty converged on a plan to leveragecollaborative teaching to launch the EEE graduate program. The faculty agreed on two importantfoundations: a core topics list (which included input and ranking by all faculty at the retreat), anda structure for a foundational graduate course. The core topics list is included as Appendix B. Inorder to catalyze the effort, maximize initial impact, and distribute the invested time widelyacross EEE faculty, a collaborative teaching model was agreed upon. Collectively, the facultywould teach six 1-credit modules in series; three starting in Spring 2016 and three in Fall 2016.Each 1-credit module (five
Conference Session
Environmental Engineering Division Technical Session 1: Intercultural Competency-infused Teaching
Collection
2021 ASEE Virtual Annual Conference Content Access
Authors
Inez Hua, Purdue University, West Lafayette
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
Hammarby Sjöstadsverk 2015 wastewater treatment Royal Institute of Technology Ocean farming research 2015, 2017 (KTH) research presentations Fossil-free bus fleets Automation in manufacturing Forest products engineering Biofuels and bioplastics Sustainable urban planning Urban Food Production Rosendal’s Garden 2017, 2019 Integrated forestry and wood and Iggesund paperboard/Holmen Group 2017, 2019 paper production Large scale extractive processes Kiruna Iron Ore Mine 2019 Climate change impacts on
Conference Session
Environmental Engineering Division Technical Session 1: Intercultural Competency-infused Teaching
Collection
2021 ASEE Virtual Annual Conference Content Access
Authors
Javiera Constanza Jofré, Universidad Andres Bello, Chile; Angeles Dominguez, Tecnologico de Monterrey, Mexico; Universidad Andres Bello, Chile
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
improving female participation in the labor market. The female activity rate remains well below the OECD average, as in 2014, only 47% of women in Chile held a job, compared to 62% in the OECD area. The Chilean government has taken steps to remedy this situation, for example, extending parental leave for maternity and postnatal birth. However, to attack the roots underlying low female participation in the workforce, the government will need to take other actions. Concerning this topic, propose an action plan, and answer why it is important to implement it, stating any probable impacts stemming from its implementation. C6 Indicate in a detailed and substantiated manner, using organizational management
Conference Session
Environmental Engineering Division Technical Session 2
Collection
2017 ASEE Annual Conference & Exposition
Authors
Freya Willicks, IMA/ZLW of RWTH Aachen University; Kathrin Schoenefeld, IMA/ZLW of RWTH Aachen University; Valerie Varney, IMA/ZLW of RWTH Aachen University; Anja Richert, RWTH Aachen University; Sabina Jeschke, RWTH Aachen University; Frank Hees, IMA/ZLW of RWTH Aachen University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
used for the project‘s organization and planning. For this purpose, there was a close cooperation with the cooperation partner’s headquarter in Berlin. The results of this cooperation were a detailed plan of the project- structure, including a goal-setting, work packages, milestones and responsibilities for each following project run. A logo was designed as well (see figure 2). In addition, the partner organization – MAVUNO Project in Tansania – for the test-run as well as for the first official run was identified. The test-run took place in the winter term 2012/13. Since the class, in which the Challenge took place for the first time, is an interdisciplinary course for different master’s programs, the participating students
Conference Session
Environmental Engineering Division Technical Session 2
Collection
2018 ASEE Annual Conference & Exposition
Authors
Charles M. Ouellette, United States Military Academy; Luke Thomas Plante, United States Military Academy; Erick Martinez P.E., United States Military Academy; Benjamin Michael Wallen P.E., United States Military Academy; Jeffrey A. Starke, United States Military Academy
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
United States Military Academy with a B.S. in Environmental Engineering and obtained an M.S. from both the University of Missouri at Rolla in Geological Engineering and the University of Texas at Austin in Environmental Engineering. Most recently, he graduated with his Ph.D. from the Colorado School of Mines in Civil and Environmental Engineering. He teaches Water Resources Planning and Management, Environmental Science, and Environmental Engineering Technologies.Col. Jeffrey A. Starke, United States Military Academy COL (Ret) Jeff Starke served as a Military Intelligence officer with command and staff experiences at the battalion, brigade, joint task force and combatant command levels. His most recent operational experi
Conference Session
Environmental Engineering Division Technical Session 1
Collection
2019 ASEE Annual Conference & Exposition
Authors
Woo Hyoung Lee P.E., University of Central Florida
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
taught duringthe semester. During the proposal development (2-3 months), participants had a regular meetingwith the principal investigator (PI) to produce ideas and discuss their findings from literaturereviews. They also conducted a brief preliminary test on the ideas which were discussed andfinalized in the laboratory. For each project, a quality assurance and quality control (QA/QC)plan was created and their potential end users and partnerships were identified for theirtechnology applications.Leadership improvementThe engineering education community has begun to focus on leadership abilities ofundergraduate students in engineering fields [5]. Higher education institutions have beencriticized for their lack of success in instilling leadership
Conference Session
Environmental Engineering Division Technical Session 3
Collection
2019 ASEE Annual Conference & Exposition
Authors
Fethiye Ozis P.E., Northern Arizona University; Nihal Sarikaya, Northern Arizona University; Adam Bringhurst
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
lesson planning and questioning techniques give the teacher more control in establishing the problem/concept and in directing and modeling scientific thought.Anecdotal evidence indicates that students express misconceptions about inversion. The currentstudy explores the influence of adding a laboratory demonstration, centered on creating an artificialinversion layer, to improve students’ conceptual understanding of inversion layer and the airquality problems associated with it. This class activity was developed for the air qualityengineering class taught for juniors and seniors in environmental engineering by expanding uponthe original demonstration created by University of Utah and Rocky Mountain Power. Theexpected student outcomes
Conference Session
Problem- Project- and Case-based Learning in Environmental Engineering
Collection
2015 ASEE Annual Conference & Exposition
Authors
Paula Ann Monaco, Texas Tech University; Maeghan Marie Brundrett, Texas Tech University; Dylan Christenson, Texas Tech University; Kevin A. Nguyen, Texas Tech University; Audra N. Morse, Texas Tech University
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
is an area they plan to focus on during thesecond semester of the capstone design course. Students were asked questions from Figure 2regarding their perceived strengths and areas for improvement. Responses to how studentsdescribed their strengths in areas related to their discipline are reflected below. “Due to the curriculum, I have strengths in water and wastewater, air pollution, and groundwater contaminants.” Page 26.678.17 “Resource accumulation and cost analysis on treatment units, water flow and regulations.” “Working in a team, equalization basins, headworks and tertiary treatment”Student responses when
Conference Session
Environmental Engineering Pedagogy and Innovation
Collection
2015 ASEE Annual Conference & Exposition
Authors
Walter McDonald, Virginia Tech; Daniel S Brogan, Virginia Tech; Vinod K. Lohani, Virginia Tech; Randel L. Dymond, Virginia Tech
Tagged Topics
Diversity
Tagged Divisions
Environmental Engineering
-Centric Feedback-Based Approach to Information Modeling and Academic Assessment. Doctor of Philosophy Dissertation, Virginia Tech, Department of Computer Engineering.32. Zint, M. and A. Kraemer, 2012. NOAA B-WET Evaluation System Plan: Student Item Bank. Bay Watershed Education and Training Program, National Oceanic and Atmospheric Administration, Washington, D.C.33. Marshall, J. A., Castillo, A. J. and Cardenas, M. B., 2013. Assessing student understanding of physical hydrology. Hydrology and Earth System Sciences, 17(2), 829-836.34. Deci, E. L., & Ryan, R. M., 1985. Intrinsic motivation and self-determination in human behavior. New York: Plenum.35. Deci, E. L., & Ryan, R. M., 1991. A motivational approach to self