Conference Session

Electrical and Computer Engineering Laboratories

Collection

2010 Annual Conference & Exposition

Authors

Thomas Schubert, University of San Diego; Ernest Kim, University of San Diego; Frank Jacobitz, University of San Diego

Tagged Divisions

Division Experimentation & Lab-Oriented Studies

singlethree-hour laboratory period. The working budget was US$800 for ten identical work stations.Such a small budget immediately eliminated the possibility of purchasing a significant number offractional-horsepower (~150W) motors and/or variable speed, three-phase drives.While each station in the electrical engineering laboratories at USD is equipped with a single208VAC (line voltage – 120 VAC phase voltage) three-phase outlet, these three-phase outletshave been historically unused for both safety concerns and the general lack of need. Since USDengineering students at the sophomore level have no experience working with voltages greaterthan ~30 V or power levels more than ~5W, and without time to teach and enforce appropriatesafety practices, it was

Conference Session

BME Laboratory and Project Experiences

Collection

2010 Annual Conference & Exposition

Authors

Purvis Bedenbaugh, East Carolina University

Tagged Divisions

Biomedical

regional students serve regionalindustry. The core curriculum trains students broadly not only in science, math and thefoundations of mechanical and electrical engineering, but also in systems and industrial processengineering. Four concentrations provide advanced training in a specific discipline. These arebiomedical engineering, bioprocess engineering, mechanical engineering, and systems andindustrial engineering. The program produced its first graduates in Spring 2008, and wasawarded ABET accreditation in 2009 - the earliest point of eligibility.The motivation for attempting this project was so that, in addition to teaching new subjectmatter, students could develop independent research skills and gain experience working in teams,in a framework

Conference Session

Innovations in the ChE Laboratory

Collection

2004 Annual Conference

Authors

Henry Lamb; David Ollis

SESSION 2213 Modern Lab Experiments for Chemical Engineering David F. Ollis and H. Henry Lamb Chemical Engineering Department North Carolina State University Raleigh NC 27695-7905 Abstract We describe new experiments developed, and installed, to bring our chemicalengineering laboratory into the 21st century. These additions are: (1) Compact disc write and re-write systems (2) Fluidized bed polymer coating (3) Hydrogen fuel cell and hydrogen storage

Conference Session

Innovations in ME Laboratory Instruction

Collection

2008 Annual Conference & Exposition

Authors

Guido Lopez, Old Dominion University; Ilya Leipunsky, Russian Academy of Science; Nadezda Berezkina, Russian Academy of Sciences

Tagged Divisions

Mechanical Engineering

AbstractIn a great majority of educational cases, “testing of materials” in the laboratory implies“destructive” techniques consisting of using universal testing machines (UTMs), where materialsare brought to a “failure condition” under tension, compression, shear, bending or torsion.Common objectives associated with these types of tests are: the evaluation of materials moduli ofelasticity and rigidity, yield strength, strain, ultimate strength, etc. In engineering practice,however, “in-situ” nondestructive testing (NDT) of materials are highly preferable, in order toevaluate rapidly the condition, failure potential, usefulness and serviceability of engineeringmaterials. Thus, nondestructive testing of materials ought to be an essential ingredient

Conference Session

Instrumentation and Laboratory Systems

Collection

2008 Annual Conference & Exposition

Authors

Jonathan Hill, University of Hartford; Akram Abu-aisheh, University of Hartford

Tagged Divisions

Computers in Education

laboratory settings,as well as in independent projects. The toolkit is being used with students during the spring 2008semester. Preliminary results will be available for the 2008 ASEE convention and alldocumentation for the toolkit is freely available on the project website1.IntroductionOptical fiber technology provides very high quality data communications over great distances.With the growing and now common use of optical fiber in industry and high-end consumerelectronics, the use of optical fiber should be more widely taught. For this purpose we aredeveloping an educational optical fiber data communications toolkit that provides students withthe means to investigate the physical layer in such a network. We first used the toolkit duringthe spring

Conference Session

Innovations in the CHE Laboratory

Collection

2009 Annual Conference & Exposition

Authors

Heather Gappa-Fahlenkamp, Oklahoma State University; Mark Wilkins, Oklahoma State University

Tagged Divisions

Chemical Engineering

processes that use bioactive agents. This is a highly transdisciplinaryfield that involves principles in both engineering: chemical, mechanical, electrical, industrial,agricultural, and environmental, and biology: biochemistry and microbiology. At our university,we offer an introductory course in Bioprocess Engineering to seniors and entering graduatestudents for any of the disciplines listed above. This course is co-taught by faculty in bothchemical engineering (CHE) and biosystems and agricultural engineering (BAE). This class canbe a challenge to teach due to the diversity of the students at different levels and from differentdisciplines.As part of their grade for the course, students participate in a “hands-on” class project designedto give the

Conference Session

Interdisciplinary and Multidisciplinary Laboratories

Collection

2009 Annual Conference & Exposition

Authors

Atin Sinha, Albany State University

Tagged Divisions

Division Experimentation & Lab-Oriented Studies

– Technical Paper # TP 89PUB512, 1989. 4. Stratasys, Inc., http://www.stratasys.com 5. 3D Digital Corporation, http://www.3ddigitalcorp.com 6. NextEngine Inc., http://www.nextengine.com 7. LeiosMesh: E.G.S. S.r.l. http://www.egsolutions.com 8. Rapidform Global Headquarters, INUS Technology, Inc. http://www.rapidform.com 9. Sinha, A., “Perspective of A Transfer Engineering Program,” Proceedings of the 2007 ASEE Conference and Exposition held in Honolulu, HI. 10. Sinha, A., “Engineering Laboratory Experiments – An Integrated Approach of Teaching the Introductory Engineering Course,” Proceedings of the 2007 ASEE Conference and Exposition held in Honolulu, HI

Conference Session

BME Laboratory and Project Experiences

Collection

2010 Annual Conference & Exposition

Authors

Sarah Pierce, Cumberland University; Amanda Lowery, Vanderbilt University; Charleson Bell, Vanderbilt University; Todd Giorgio, Vanderbilt University

Tagged Divisions

Biomedical

research as the techniquesused are necessary to understand many aspects in bioscience.” Page 15.900.11Instructor Prep and InvolvementThis was the first time a bionanotechnology laboratory course was offered. The completely newlab exercises required new readings, new protocols, and new discussion questions. The teachingassistant completed each exercise in a trial run before the course began. The trial run determinedthe clarity of the protocols and the appropriate time points for student data collection. This typeof verification is expected for a new course but did add to the teaching assistant responsibilities.During each lab period both the

Conference Session

Laboratory Development in ECE

Collection

2010 Annual Conference & Exposition

Authors

R.F. William Hollender, Montana State University; James Becker, Montana State University

Tagged Divisions

Electrical and Computer

most benefit in terms of using the material later in their careers and so thesesomewhat esoteric topics were removed from the course. Based on one of the author’sexperience in teaching students at Montana State over the last eight years, and in following whatmany of the EE 433 students do after graduation, the most common tasks that align withpotential content for EE 433 include RF/microwave board layout, component selection, andcircuit-level and system-level calculations. It is interesting to note that not one student hasindicated that he/she is involved with distributed filter design. In place of the lectures devotedto the theory of distributed element filter design, time in lecture was opened for discussing thefundamentals of Doppler radar

Conference Session

ECE Laboratory Development and Innovations

Collection

2002 Annual Conference

Authors

Daniel Beenfeldt; John Field; Eric Beenfeldt; Edward Williams

students and faculty to post comments,questions, and answers for all to share. It also allows documents to be attached to messages sothat they can be downloaded by all. We make particular use of this latter feature to distributehomework and laboratory assignments. Educational objectives for ECE 171 are described next.III. Educational ObjectivesListed below are the major educational objectives for ECE 171.The student will be able to:1. Express signed and unsigned numbers in hexadecimal, decimal, and binary.2. Interpret and use data correctly depending on the situation. Page 7.166.2 Proceedings of the 2002 American Society for Engineering

Conference Session

Mechanical Engineering Laboratories II

Collection

2011 ASEE Annual Conference & Exposition

Authors

John M Mativo, University of Georgia; Natasha Smith, University of Southern Indiana

Tagged Divisions

Mechanical Engineering

AC 2011-731: LEARNING IN LABORATORY COMPLIMENTS TO LEC-TURE COURSES VIA STUDENT DESIGNED AND IMPLEMENTED EX-PERIMENTSJohn M Mativo, University of Georgia Taught and researched at university level for 16 years of which 6 served as department chair. Subject area involvement in teaching and research were in engineering education; product development and manufac- turing; and energy systems. Member of ASME, ASEE, ITEEA and Sigma Xi.Natasha Smith, University of Southern Indiana Page 22.1005.1 c American Society for Engineering Education, 2011 Learning in Laboratory Compliments to

Conference Session

ME Demonstrations and Laboratories

Collection

2017 ASEE Annual Conference & Exposition

Authors

Jeffrey C. Hayen, Oregon Institute of Technology

Tagged Divisions

Mechanical Engineering

theend of this article). It is the inaugural experiment undertaken for this course, and it is typicallyperformed during the second week of an academic term since the necessary background materialis reviewed during the laboratory session of the first week. This activity lends itself well to thisplacement within the laboratory schedule because it involves the unforced (or ‘free’) vibration ofa single-degree-of-freedom (SDOF) system that is almost undamped, so it essentially illustratessimple harmonic motion. Also, it does not depend upon advanced concepts or principles whichare covered at later stages in the course, yet it is easy to perform and does not require expensiveequipment or elaborate instruments.Before they perform the experiment, the

Conference Session

BME Laboratories and Projects

Collection

2019 ASEE Annual Conference & Exposition

Authors

Steve Warren, Kansas State University; Charles Carlson, Kansas State University; Dong Xu Ren, Kansas State University

Tagged Divisions

Biomedical Engineering

student interest. Dr. Warren is a member of the American Society for Engineering Education and the Institute of Electrical and Electronics Engineers.Dr. Charles Carlson, Kansas State University Charles Carlson received a B.S. degree in Physics from Fort Hays State University in 2013 as well as B.S., M.S., and Ph.D. degrees in Electrical Engineering from Kansas State University in 2013, 2015, and 2019, respectively. Charles is currently a Graduate Teaching and Research Assistant in Electrical and Computer Engineering at Kansas State University (KSU). He works in the KSU Medical Component Design Laboratory and is interested in engineering education, bioinstrumentation, and bioinformatics. He is a member of the American

Conference Session

Laboratory Development in ECE II

Collection

2013 ASEE Annual Conference & Exposition

Authors

Mario Simoni, Rose-Hulman Institute of Technology; Maurice F. Aburdene, Bucknell University; Farrah Fayyaz, Purdue University

Tagged Divisions

Electrical and Computer

Paper ID #6528Analog-Circuit-Based Activities to Improve Introductory Continuous-TimeSignals and Systems CoursesDr. Mario Simoni, Rose-Hulman Institute of Technology Dr. Simoni is an Associate Professor of Electrical and Computer Engineering at Rose-Hulman Institute of Technology in Terre Haute, IN.Prof. Maurice F. Aburdene, Bucknell University Maurice Felix Aburdene is a Professor of Electrical Engineering and Professor of Computer Science at Bucknell University. His teaching and research interests include control systems, parallel algorithms, simulation of dynamic systems, and signal processing.Ms. Farrah Fayyaz, Purdue

Conference Session

ECE Laboratory Development & Innovations

Collection

2004 Annual Conference

Authors

Ahmed Rubaai

Session 3432 DESIGN OF INTELLIGENT CONTROLLERS FOR DC-DC CONVERTERS IN UNDERGRADUATE ENGINEERING LABORATORY Ahmed Rubaai, Mohamed Chouikha, Abdul Ofoli and Sahar Kaddah Howard University Electrical and Computer Engineering Department 2330 6th Street, Northwest Washington, DC 20059Abstract The primary goal of this paper is to develop a vehicle through which undergraduatestudents may design smart controllers that employ artificial intelligence

Conference Session

BME Laboratory and Project Experiences

Collection

2012 ASEE Annual Conference & Exposition

Authors

Donna M. Ebenstein, Bucknell University; Eric A. Kennedy, Bucknell University

Tagged Divisions

Biomedical

based biocompatibility module with laboratory and lecture components that can be easilyintegrated into an engineering or biomaterials course.Within the biomedical engineering curriculum at Bucknell University, a senior-level fabricationand experimental design course is integrated into a four course design sequence where twocourses comprise the senior capstone experience and two courses teach supplementary material.The intent of the sequence is to provide experience with a variety of skills that are valuable forboth senior design projects and in BME careers after graduation. As designed, the Fabricationand Experimental Design course is not a full-credit course, meeting only two days a week forone-hour sessions, with several lab sessions

Conference Session

Mechanical Engineering Laboratories I

Collection

2011 ASEE Annual Conference & Exposition

Authors

Richard J. Ruhala, Southern Polytechnic State University

Tagged Divisions

Mechanical Engineering

and one agreed with achieving thatlearning outcome.From an engineering education research standpoint, it would be very useful to compare thecourse learning outcomes with and without the laboratory component. Unfortunately there wasno lecture-only vibrations course taught before the lab was developed at USI that could be usedfor comparison. Also, it would not be fair to current students to intentionally teach the vibrationscourse without a hands-on laboratory component.Table 1: Assessment of some of the laboratory learning objectives as evaluated for the 2009 fall semester.Each student evaluated each objective as 1 for strongly disagree, 2 for disagree, 3 for neutral, 4 for agree, and5 for strongly agree. The average score is based on 7

Conference Session

Instrumentation and Laboratory Systems

Collection

2004 Annual Conference

Authors

Yan-Fang Li; Sang-Hoon Lee; Vikram Kapila

) bus,USART ports, etc. We use an external 20 MHz high-speed crystal oscillator to supply operatingclock cycles. The PIC16F74 can be powered using a wide range of voltage sources, e.g., 2-voltdirect current (VDC) to 5.5VDC, and each of its I/O pin can sink or source up to 25mA ofcurrent. It is ideal not only for laboratory data acquisition (the application considered in thispaper), but also for automotive, industrial, and consumer applications. (a) (b) Figure 1: (a) PIC16F74 (b) Pin diagram of PIC16F742.2. Personal Computer In this paper, an IBM-compatible Pentium 3 PC running Microsoft Windows NT 4.0operating system is used. As

Conference Session

Energy Projects and Laboratory Ideas

Collection

2005 Annual Conference

Authors

Philip Gerhart; Andrew Gerhart

Session 3133 Laboratory-Scale Steam Power Plant Study – Rankine CyclerTM Effectiveness as a Learning Tool and its Component Losses. Andrew L. Gerhart1, Philip M. Gerhart2 1 Lawrence Technological University, Southfield, MI 48075 2 University of Evansville, Evansville, IN 47722AbstractThe Rankine Cycler™ steam turbine system, produced by Turbine Technologies, Ltd., is a table-top-sized working model of a fossil-fueled steam power plant. It is widely used by engineeringcolleges around the world.The objectives of this

Conference Session

Remote and Network-based Laboratories

Collection

2012 ASEE Annual Conference & Exposition

Authors

Rick Williams, East Carolina University; Loren Limberis, East Carolina University; Rebel Umphlett, BioNetwork Capstone Center; David Hobson Yarley, BioNetwork Capstone Center

Tagged Divisions

Division Experimentation & Lab-Oriented Studies

Education: A Multiple Case Study*,” Journal of Engineering Education, Vol. 88, 1999, pp. 429-434.5. Kelly, C., Grummer, E., Harding, P., and Koretsky, M., “Teaching Experimental Design using Virtual Laboratories: Development, Implementation and Assessment of the Virtual Bioreactor Laboratory,” Proceedings of the 2008 ASEE Annual Conference and Exposition, Pittsburg, PA, 2008.6. Guimarães, E., Maffeis, A., Pereira, J., Russo, B., Cardozo, E., Bergerman, M., and Magalhães, M., “REAL: A Virtual Laboratory for Mobile Robot Experiments,” IEEE Transactions on Education, Vol. 46, No. 1, 2003, pp. 37-42.7. Window on the Workplace 2003, A Training Needs Assessment of the Biomanufacturing Workforce, North Carolina Biotechnology Center

Conference Session

Innovations in Manufacturing Laboratories

Collection

2015 ASEE Annual Conference & Exposition

Authors

Jeremy John Vaillant, University of Massachusetts, Lowell ; Christopher J. Hansen, University of Massachusetts, Lowell; Stephen Johnston, University of Massachusetts, Lowell; Sammy G. Shina, University of Massachusetts, Lowell; David Willis, University of Massachusetts, Lowell

Tagged Divisions

Manufacturing

Lowell.3.1 Lab Setup and Facility RequirementsThe requirements of a successful CNC laboratory include: adequate space, proper electrical ser-vice, and adequate personnel resources, such as teaching assistants and IT support for the com-puters.34 The laboratory at University of Massachusetts Lowell has been setup in “CNC bays” toaccommodate groups of up to four students per CNC machine. A CNC mill and a computer canbe seen in Figure 3-1. Figure 3-1: Single Table Setup for a ShapeOko II CNC Mill.The CNC laboratory space occupies approximately 750 ft2 of a 1700+ ft2 laboratory that whatwas formerly used for aerodynamics experiments and senior capstone design. The space satisfiesmany requirements for setting up a lab including

Conference Session

Alternative Teaching Methods

Collection

2018 ASEE Annual Conference & Exposition

Authors

Susan Scachitti, Purdue University Northwest; James B. Higley, Purdue University Northwest

Tagged Divisions

Engineering Technology

learning outcomes with correlated course assessment grades and student subjective survey results Spring 2017, IET 22400 IET 22400 Instructor Update InformationDate Submitted: Spring 2017 Date to be Reviewed: May 2018Responsible faculty for the review: xxx Type of Update New Edition of the Text New Text Adopted New Software Teaching Method New Laboratory Equipment Lab Material Update Teaching

Conference Session

Thermodynamics, Fluids, and Heat Transfer II

Collection

2010 Annual Conference & Exposition

Authors

Michael Maixner, United States Air Force Academy; William Parker, Air Force Research Laboratories

Tagged Divisions

Mechanical Engineering

AC 2010-48: DESIGN OF A MULTI-MODE FINITE-DIFFERENCE HEATTRANSFER PROJECTMichael Maixner, United States Air Force AcademyWilliam Parker, Air Force Research Laboratories Page 15.358.1© American Society for Engineering Education, 2010 Design of a Multi-Mode Finite-Difference Heat Transfer ProjectAbstract: The development of a comprehensive inite-difference project at the end of a heattransfer curriculum is described. The problem requires evaluation of the school’s football ieldturf heating system, incorporates all of the major heat transfer modes (convection, conduction,and radiation), and requires students to investigate both steady state and transient versions ofthe problem

Conference Session

NSF Grantees Poster Session

Collection

2010 Annual Conference & Exposition

Authors

Ashley Clayson, Laboratory for Innovative Technology and Engineering Education; P K Raju, Auburn University; Chetan Sankar, Auburn University

. Sankar is a Professor of Management at the Auburn University's College of Business. He received his Ph.D. from the Wharton School, University of Pennsylvania and has worked at Temple University and AT&T Bell Laboratories. His research interests focus on researching innovative practices to integrate teaching, research, and outreach both locally and globally (www.litee.org). He has published more than 150 papers in journals, book chapters, and conference proceedings. He has won awards for research and teaching from the Society for Information Management, iNEER, Decision Sciences Institute, American Society for Engineering Education, Frontiers in Education, and the Project Management

Conference Session

Innovative Teaching Techniques

Collection

2005 Annual Conference

Authors

Eric Hamilton; Gregor Novak; Evelyn Patterson; Brian Self

the idea, but different students willgrasp different aspects of the subject matter. By presenting the answers from different studentsthe instructor can build up an understanding of the complex idea. In this way, students feelgreater ownership of the course, come better prepared to class, and have more productiveinteractions with the professor. Examples of the use JiTT in undergraduate physics will bepresented and a framework for applying the techniques to Mechanics described.IntroductionThe physics educational community has long been at the forefront of innovative pedagogy.Instructors have developed interesting hands-on demonstrations, laboratories, and examples tophelp motivate and teach their students. The Force Concept Inventory(1) has

Conference Session

Curriculum Development & Assessment in Nuclear and Radiological Engineering

Collection

2006 Annual Conference & Exposition

Authors

Mary Lou Dunzik-Gougar, Idaho State University; Michael Lineberry, Idaho State University; Leonard Bond, Idaho National Laboratory

Tagged Divisions

Nuclear and Radiological

Design I Project Design IICollaboration with CAES and INL comes about in several fundamental ways. First, there will bea six-month “practicum” beginning the summer between the junior and senior years, which willinclude participation in major R&D projects at the INL, including a start on the required seniordesign project. Second, efforts are nearing completion to arrange the nuclear laboratory course tobe taught during the practicum period at certain of the unique INL nuclear test facilities. Third,special adjunct teaching arrangements are being made with INL/CAES researchers both to help Page 11.1248.3with the

Conference Session

Improving Teaching & Learning

Collection

2004 Annual Conference

Authors

Sandra Courter; Mary McEniry; Cid Freitag

about teachingand learning in the process of building a learning community, 3) create a collaborativelearning environment with faculty and peers, 4) build confidence in curriculumdevelopment including designing, guiding, and assessing learning, 5) learn with andabout technology in the process of improving curriculum, and 6) connect teaching andresearch and bridge the gap between theory and practice. The twenty participantsrepresented ten universities; a team of two from each university included one facultyperson from engineering and one from another science, math, or computer sciencediscipline. Specifically, the professional development opportunity explored ways ofknowing including theories of learning, learning styles, disciplinary and

Conference Session

Teaching Communication I

Collection

2014 ASEE Annual Conference & Exposition

Authors

Rebecca R Essig, Purdue University; Cary David Troy, Purdue University, West Lafayette; Brent K Jesiek, Purdue University, West Lafayette; Josh Boyd, Purdue University; Natascha Trellinger Buswell, Purdue University, West Lafayette

Tagged Divisions

Liberal Education/Engineering & Society

demonstrate non-technical student outcomes, including those pertaining to ethics,global issues, economics, and understanding of environmental and societal contexts.2When the objective is to improve student writing skills (“learning to write”), an integrated, orwriting across the curriculum (WAC) approach to teaching technical writing is consideredfavorable over the alternative of isolated, stand-alone communication courses that oftendecontextualize writing.3-4 In the integrated approach, communication instruction and practice isdistributed throughout the curriculum and embedded in technical courses, well beyond thestandard inclusion of laboratory reports in laboratory classes. Such an approach also maximallyleverages the writing process towards the

Conference Session

Alternative Teaching Methods

Collection

2018 ASEE Annual Conference & Exposition

Authors

Emel Cevik, Texas A&M University; Michael Johnson, Texas A&M University; Bugrahan Yalvac, Texas A&M University; Jennifer G. Whitfield, Texas A&M University; Mathew Kuttolamadom, Texas A&M University; Jay R. Porter, Texas A&M University; Joseph A. Morgan, Texas A&M University

Tagged Divisions

Engineering Technology

Paper ID #21535Assessing the Effects of Authentic Experiential Learning Activities on TeacherConfidence with Engineering ConceptsEmel Cevik, Texas A&M UniversityDr. Michael Johnson, Texas A&M University Dr. Michael D. Johnson is an associate professor in the Department of Engineering Technology and In- dustrial Distribution at Texas A&M University. Prior to joining the faculty at Texas A&M, he was a senior product development engineer at the 3M Corporate Research Laboratory in St. Paul, Minnesota. He received his B.S. in mechanical engineering from Michigan State University and his S.M. and Ph.D. from the

Conference Session

Student Division Development of Professional Skills Technical Session

Collection

2017 ASEE Annual Conference & Exposition

Authors

Charles Avery Noren, Texas A&M University Vehicle Systems & Control Laboratory; Kendra Lynne Andersen, Texas A&M University; Kanika Gakhar, Texas A&M University Vehicle Systems and Control Laboratory; Angela Olinger, Texas A&M University; Preetam Palchuru, Texas A&M University Vehicle Systems & Control Laboratory; Scott Thien Tran, Texas A&M University Vehicle Systems & Control Laboratory; John Valasek, Texas A&M University

Tagged Divisions

Student

;M University Vehicle Systems & Control Laboratory Scott Tran is an undergraduate research assistant at the Texas A&M University Vehicle Systems & Control Laboratory. Expected to graduate with a Bachelor of Science in May 2018.Dr. John Valasek, Texas A&M University John Valasek is the Thaman Professor of Undergraduate Teaching Excellence, and Director, Center for Autonomous Vehicles and Sensor Systems (CANVASS), Director, Vehicle Systems & Control Labora- tory, Professor of Aerospace Engineering, and member of the Honors Faculty at Texas A&M University. He teaches courses in Aircraft Design, Atmospheric Flight Mechanics, Modern Control of Aerospace Sys- tems, Vehicle Management Systems, and