Dec 12, 2024  
2022-2023 Undergraduate Catalog 
    
2022-2023 Undergraduate Catalog [ARCHIVED CATALOG]

Tickle College of Engineering


College Admission Requirements
Readmission
Facilities
Advising Services
Honors
Engineering Professional Practice
International Engineering Program
Graduate Program
Tau Beta Pi National Headquarters
National Accreditation
Designation of a Minor
Course Load
Transfer Students
   — Transfer Credit

Second Bachelor of Science Degree
University General Education Requirement
American History Requirement
Technical Electives
The Voluntary ROTC Program
Approval of Electives and Substitutions
Curricula
   — Prerequisites
Probation and Dismissal Procedures
   — Academic Probation in Engineering
   — Dismissal from Engineering
Five-Year BS/MS with Physics Minor
VolsTeach Program
uTrack Requirements
Academic Programs


Matthew Mench, Dean
William M. Dunne, Associate Dean for Research and Technology
Paul D. Frymier, Associate Dean for Faculty Affairs

Ozlem Kilic, Associate Dean for Academic and Student Affairs
John D. Schmisseur, Associate Dean and Director UTSI
Jeremy C. Kirk, Assistant Dean of Diversity, Equity, and Inclusion

R. Keith Stanfill, Edwards Assistant Dean, Director, Integrated Engineering Design
Rachel Ellestad, Director, Engineering Fundamentals Program

Travis T. Griffin, Director, Engineering Diversity Program
Kevin Kit, Director, Engineering Honors Program
Todd Reeves, Director, Engineering Professional Practice
Margaret Russell, Director, Engineering Advising Services

http://www.engr.utk.edu/

Engineers solve problems. To do so, they apply science, mathematics, and creativity to invent, design, test, build, and operate engineering systems that will meet the needs of society. In the latter half of the 20th century, engineers developed the personal computer, the space shuttle, artificial hearts, and many other “high-tech” products. The opportunities to use technology for the benefit of 21st century society will be even greater.

Engineers use the same problem-solving strategies whether designing a bridge, trouble shooting a computer chip problem, or developing a more efficient automobile engine. This commonality of approach makes it easy for an engineer to move from one specialization to another. The engineer’s can-do, problem solving outlook is also good preparation for management, and many engineers follow this career path.

Increasingly, engineers must also have good interpersonal skills to work effectively in the interdisciplinary groups required to tackle modern engineering projects. They must understand the ethical, environmental, social, political, and business implications of their work. Engineers must work comfortably among the cultures, customs, and languages of multi-national enterprises.

In light of modern society’s ever-increasing dependence on technology, there is a continuing and urgent need for engineering graduates who possess the high levels of technical competence and social understanding that will enable them to fulfill their responsibilities as professional engineers. The Tickle College of Engineering prepares all students to face these challenges and to seize opportunities to become the technology leaders of the 21st century.

Graduates of the Bachelor of Science curricula offered by the college may enter directly into a position in industry, government, or private practice, or may pursue advanced study in graduate school. Their professional activities include research, development, design, operations analysis, construction, production supervision, and technical sales. Many practice their profession in Tennessee; but engineering knows no geographical bounds, and graduates of the college serve throughout the nation and in other countries as well.

The college offers eleven undergraduate majors – aerospace engineering, biomedical engineering, chemical engineering, civil engineering, computer engineering, computer science, electrical engineering, industrial engineering, materials science and engineering, mechanical engineering, and nuclear engineering.

Biosystems engineers use engineering science and mathematics to address opportunities and problems in biological, environmental, ecological, and agricultural systems. This program is accredited by the Engineering Accreditation Commission of ABET, http://www.abet.org and is offered by the Department of Biosystems Engineering and Soil Science in the Herbert College of Agriculture in cooperation with the Tickle College of Engineering. For program requirements, click here .

The college, in cooperation with industrial sponsors, established the Minority Engineering Scholarship Program in 1973 and in 1999 renamed it the Diversity Engineering Scholarship Program. The program’s goal is to increase significantly the number of qualified minority engineering graduates. This program is maintained in the Engineering Professional Practice Office.

College Admission Requirements

The University of Tennessee and the Tickle College of Engineering have decided to make standardized test scores optional for the 2021 application.

Admissions criteria is based on several performance criteria, including completion of core academic subjects, GPA scores on these subjects, and standardized test (SAT or ACT) scores, if submitted.

Test-Optional Applicants

For those students who choose not to submit test scores, you will be considered a test-optional student. Applicants will be reviewed for admission using high school core GPA weighted of 3.80 or higher and grades earned in four math courses, including pre-calculus or higher and one unit of chemistry. Advanced placement/International Baccalaureate and dual enrollment math and chemistry courses will be included with this holistic review.

Test Score Optional examples:

  • 3.80-3.99 High School Core GPA Weighted
  • 4 units of high school math including pre-calculus or higher, grade achieved A (including AP/IB and dual enrollment math and chemistry)
  • 1-unit Chemistry, grade achieved A

OR

  • 4.00+ High School Core GPA Weighted
  • 4 units of high school math including pre-calculus, grade achieved B or better (including AP/IB and dual enrollment math and chemistry)
  • 1-unit Chemistry, grade achieved B or better

Applicant Applying with Test Scores

A Success Prediction Indicator (SPI) number of 60 and a math ACT of 25 or a math SAT of 590 if taken after March 2016 (math SAT of 570 if taken before March 2016) are minimum standards used for admission to the college. The SPI is calculated by adding an individual’s ACT mathematics score to 10 times their core high school GPA (based on a 4.0 scale). For information on what constitutes core high school courses, please consult the admission website. Student denied entry to TCE under test score criteria will be considered under test-optional criteria.

SPI EXAMPLE: A student with a high school core GPA of 3.5 and an ACT mathematics score of 28 would have an SPI of 63 using the formula (3.5 X 10) + 28 = 63. SAT scores are converted to an equivalent ACT score to perform this calculation.

Students who wish to pursue an engineering degree at UT but do not meet the college admission criterion may enroll as University Exploratory students and complete appropriate mathematics, science, and other courses before applying again for admission to the college.

Students denied admission to TCE based on test score and/or test optional criteria may follow the TCE Internal Transfer Admissions policy and process as stated in the Undergraduate Catalog.

Readmission

Returning dismissed and probationary students will not be readmitted to a major in the Tickle College of Engineering and should explore other options with the appropriate college advising center. Returning students in good standing will be readmitted to their major but must meet with an academic advisor to discuss the appropriate course of action.

Facilities

Most of the college’s facilities are on the southeastern corner of “The Hill.” Engineering Advising Services, Engineering Fundamentals Program, Engineering Diversity, Engineering Honors Program, Engineering Student Success, and Engineering Professional Practice are located in the Zeanah Engineering Complex. Civil Engineering, and Industrial Engineering are in the John D. Tickle Building; Electrical Engineering, Computer Engineering, and Computer Science are in the Min H. Kao Building; Mechanical Engineering, Aerospace Engineering, Biomedical Engineering, and Chemical Engineering are in Dougherty Hall; Materials Science and Engineering is in Ferris Hall; Nuclear Engineering is in the Zeanah Engineering Complex. Interdisciplinary Engineering Research Centers are located in various campus buildings (http://www.engr.utk.edu/research/).

Advising Services

http://www.engr.utk.edu/advising/

The Engineering Advising Office provides excellent academic program planning services to undergraduate students in the Tickle College of Engineering, with specific attention given to the freshman class. Central to the mission of academic advising at the university is teaching students to understand the purpose of the curriculum and fostering their intellectual and personal development toward academic success and lifelong learning. Through individual, collaborative relationships with academic advisors students are best able to define and implement sound educational plans that are consistent with their personal values, goals, and career plans.

The Tickle College of Engineering is committed to the belief that academic advising engages students by teaching them how to become members of the higher education community, to think critically about their role and responsibilities as engineers, and to prepare them to be educated members of a global community. The students’ learning outcomes of academic advising in the college are to craft a coherent educational plan based on assessment of abilities and interests; use a variety of campus resources to set goals, reach decisions, and achieve those goals; assume responsibility for meeting academic program requirements; cultivate the intellectual habits that lead to a lifetime of learning; and behave as citizens who engage in the wider world around them. The Advising Services Office is located in 160 Zeanah Engineering Complex (ZEC). The office can be reached by phone at (865) 974-4008 or email (engradvising@utk.edu).

New freshman students are assigned to Engineering Advisors for academic advising. Freshman students admitted to the Tickle College of Engineering are required to designate a field of study by the end of their freshman year. Departmental faculty are expected to engage with undergraduate students regarding research opportunities, graduate school considerations, and specific course content in their program of study. 

Freshmen admitted into the Tickle College of Engineering starting in MATH 130  (Pre-calculus) or MATH 131  (Calculus 1A Infused with Pre-calculus) with Math ACT of 25, 26, or 27 (SAT Math equivalents 590 - 650) are expected to follow the showcase below during the freshman year:

Fall Spring Summer
ENGL 101 *or ENGL 118 * or ENGL 131 * or ENGL 198 * ENGL 102 * or ENGL 132 * or ENGL 290 * or ENGL 298 *  
MATH 131   MATH 132 * MATH 142 *
EF 141 * EF 142 * EF 152 *
Volunteer Core class CHEM 122 * and CHEM 123 *  
Volunteer Core class or COSC 101  (for EECS majors only) Volunteer Core class or COSC 102  (for EECS majors only)   
First Year Studies course    

Advisors will work individually with each student to create a course plan for academic success.

Honors

Tickle College of Engineering Honors Programs

The Tickle College of Engineering administers the Cook Grand Challenge Honors Program (CGCHP) in cooperation with the TCE departmental honors concentrations (HC). This program is independent of (but complementary to) the university’s Chancellors Honors Program (CHP), and an engineering student may choose to pursue both programs. In addition, the College administers the Grand Challenge Scholars (GCS) program in cooperation with the National Academy of Engineering.

Cook Grand Challenge Honors Program/Departmental Honors Concentration

Admission

Admission as a first year student to the CGCHP/HC is by invitation, which is extended by the Dean’s office to students meeting rigorous academic standards in their high school coursework. Students not invited may apply after completing their first semester at The University of Tennessee. Recent entering classes have had an average high school core GPA of above 4.0 and an average composite ACT of 33.

Admission as a transfer student or after completing significant coursework at the University of Tennessee is by application to the Honors Director in consultation with the departmental honors concentration in the student’s major department.

Engineering Honors students are expected to make reasonable but timely progress towards the coursework and breadth requirements while maintaining a minimum cumulative GPA of 3.4. Students will be dismissed from the program if they fail to meet these requirements.

Requirements:

Coursework requirement

  • Four 100- or 200-level honors courses* (14 hours minimum, at least two courses must be from Engineering Fundamentals, Physics, Math, Chemistry, Biology, Statistics, or MSE 207 ).
  • Coursework requirements in the upper-division are specific to the individual departments and the student is referred to those individual descriptions for explanation.

*While most students fulfill this requirement with 100- and 200-level courses, students may substitute upper level courses on approval of the Honors faculty.

GPA Requirement:

A minimum GPA to maintain and graduate with a Departmental Honors Concentration may be required by the individual departments, see departmental description.

Breadth Requirement:

An honors student is expected to broaden their undergraduate experience beyond a prescribed curriculum. CGCHP/Honors Concentration students must satisfy two of the five National Academy of Engineering (NAE) Grand Challenge Scholars Requirements listed below. One of these must be at an intermediate level and the other at an introductory level. See College website for details and level descriptions.

  1. A research experience.
  2. Interdisciplinary coursework* that prepares a student to work at the boundary of engineering with public policy, business, ethics, risk, and human behavior.
  3. An entrepreneurship experience to prepare students to translate invention to innovation.
  4. A global experience to build the student’s perspective of these global issues.
  5. A service learning experience to deepen students’ motivation to bring their technical expertise to bear on societal problems.

*Students who satisfy the Chancellors Honors Program (CHP) course requirements will satisfy the interdisciplinary coursework requirement at an Intermediate level. Other CHP curricular and extracurricular activities may be counted towards the CGCHP/Honors Concentration Breadth Requirements if they meet the requirements shown on the college website.

These Breadth Requirements are designed such that students may choose to build on these in order to satisfy all of the requirements of the Grand Challenge Scholars Program.

NAE Grand Challenge Scholars Program

The National Academy of Engineering Grand Challenge Scholars Program is a combined curricular and extracurricular program with five breadth components that are designed to prepare students to be the generation that solves the grand challenges facing society in this century. These breadth requirements are listed above for the CGCHP/Honors Concentration.

This program is for students who wish to build a broad level of experience in all the NAE areas into their undergraduate program. It requires one Extensive experience, two Intermediate experiences, and two Introductory Experiences. A qualified research experience must be related to one of the 14 NAE Grand Challenges.

Engineering Professional Practice

https://www.coop.utk.edu/

The University of Tennessee Tickle College of Engineering encourages all its students to obtain relevant paid work experience through the Engineering Professional Practice program. Engineering students can choose to participate in Cooperative (Co-op) Engineering or the College’s Internship Program. Both offer qualified assignments that are an integral part of the educational process, as well as help UT engineers identify skills, build networks, and foster relations in the engineering community.

Since 1926, UT engineers have blended classroom theory with practical engineering application in corporate or government settings. The Co-op Engineering Program is a study-work plan of education in which a student alternates periods of campus coursework with periods of employment in industry related to the student’s major. As the second oldest Co-op Engineering Program in the south, most UT engineers work in assignments across the United States, however, more students are seeking opportunities internationally. Currently, over 40% of the undergraduate engineering students register and pursue one of the many positions available. One of the value added components is that all positions are paid. Salaries vary between organizations and locations. Most students are able to offset a substantial amount of college expenses with earnings from co-op and internships. We encourage our students to seek exposure that offers depth and skills development.

Professional staff will work in conjunction with advisors to outline an academic-work plan (Degree Plan), and address scholarship issues to schedule cycles of full-time academic terms with alternating terms of work. The University of Tennessee believes that this process offers a “real world” understanding of after graduation expectations. It also affords each student feedback from the employer to help gauge areas of interest and career direction. An added incentive, many companies hire their Co-op students for full-time employment after graduation.

Internships through the Engineering Professional Practice Office follow the same standard of quality, but tend to be just one term. Most internships are offered in the summers (10-13 weeks) and are very competitive; and just like Co-op Engineering assignments, are monitored by university professionals. Sound advising helps intern candidates pursue positions offered at times other than summers.

All students in the Tickle College of Engineering can participate and should begin reviewing these opportunities during their first semester at UT. Because of changing economic trends, some engineering majors may be in greater demand and selection criteria will vary among organizations. Students completing at least 52 weeks of approved work experiences will receive the Program’s Cooperative Engineering Certificate. All students participating in internships and co-op engineering programs through the Engineering Professional Practice Office enroll in EF 333  (1) for each semester employed in a co-op or internship assignment for a maximum of 3 hours.

Further details are available on our website (www.coop.utk.edu) or write to: Engineering Professional Practice; 310 Perkins Hall; Knoxville, Tennessee 37996-2030.

International Engineering Program

http://www.engr.utk.edu/study-abroad/

The United States, like most countries throughout the world, can no longer thrive economically with only a domestic market for its goods and services. To compete in the global marketplace, engineers must understand how to design and manufacture products for world-wide use. The Tickle College of Engineering works with several organizations, both on and off campus, to enable interested students to participate in significant engineering experiences abroad. Students interested in making an international experience part of their engineering education should begin exploring opportunities and develop plans during the freshman year. Language preparation to a level of substantial proficiency may be required. Thus, language preparation should be started immediately. For further information on international engineering educational programs, contact the Center for Global Engagement, 1620 Melrose Avenue, or http://www.engr.utk.edu/global/, or the Engineering Advising Office.

Graduate Program

Graduate programs leading to the Master of Science are offered in fourteen majors – aerospace engineering, biomedical engineering, chemical engineering, civil engineering, computer engineering, computer science, electrical engineering, engineering science, environmental engineering, industrial engineering, materials science and engineering, mechanical engineering, nuclear engineering, and reliability and maintainability engineering. The Doctor of Philosophy is offered in thirteen majors – aerospace engineering, biomedical engineering, chemical engineering, civil engineering, computer engineering, computer science, electrical engineering, engineering science, industrial engineering, materials science and engineering, mechanical engineering, and nuclear engineering. See the Graduate Catalog for information on these programs.

Tau Beta Pi National Headquarters

The college is honored to have the national headquarters of Tau Beta Pi, the Engineering Honor Society, housed on our campus since 1907. This honor was earned in part through the untiring efforts of R.C. “Red” Matthews, Secretary-Treasurer for the organization from 1905 to 1947. The suite of offices, located in Dougherty Hall, is occupied by Mr. J.D. Froula, Secretary-Treasurer, R.E. Hawks, Assistant Secretary-Treasurer, and eight additional staff members.

National Accreditation

All undergraduate engineering programs at the University of Tennessee are accredited by the Engineering Accreditation Commission of ABET, http://www.abet.org. The undergraduate computer science program at the University of Tennessee is accredited by the Computing Accreditation Commission of ABET, http://www.abet.org.

Designation of a Minor

An engineering undergraduate may declare a minor in an engineering or a non-engineering subject area and have the minor listed on the permanent record under the following conditions.

  • Minors must be officially approved and described in the Undergraduate Catalog. No unofficial minors will be recognized.
  • Courses taken to satisfy the minor may also be used to satisfy engineering degree requirements provided that the courses would be a part of engineering degree requirements even if no minor was declared. Completion of a minor often involves the taking of some courses which cannot be used to satisfy the minimum requirement for an engineering degree.
  • A student should notify his or her advisor and major department office when beginning work on a minor. The intention to complete a minor must be declared at the time of application for graduation if the minor is to appear on the final transcript. 

Course Load

The maximum number of hours which can be taken by an undergraduate engineering student without special permission is 19. The Associate Dean for Academic and Student Affairs (or designee) must give permission to take 20 hours or more. In general, this decision is based on the student’s previous performance at the University of Tennessee, Knoxville. Students can obtain the required paperwork to request an overload either in the Engineering Advising Services Office or on the Tickle College of Engineering website (http://www.engr.utk.edu/advising/ or http://www.engr.utk.edu/advising/forms/).

Transfer Students

Transfer students, including internal University of Tennessee, Knoxville, transfers, must meet the minimum requirements stated below to be considered for admission to a major within the college. These minimum standards for consideration do not guarantee being admitted to the major. The final admission decision for the major resides with the department head or designee.

  • Must have earned a minimum 2.8 cumulative average and a C or better in each of these specific courses, or their equivalent: ENGL 101 *, CHEM 122 * and CHEM 123 * formerly CHEM 120* (for Computer Science students: COSC 101  and COSC 102  or equivalents), and MATH 132 * or MATH 141 * (and subsequent courses in the three sequences, if taken). 
  • If the student has completed any physics course, he/she must have earned a grade of C or better.
  • The overall record will be evaluated for quality and seriousness of purpose. An excessive number of withdrawals, incompletes, repeated courses, or failures may result in denial.

Any University of Tennessee, Knoxville, student desiring association with one of the departments in the Tickle College of Engineering should go to the Engineering Advising Office. An advising session is held with the major items of consideration being the same as for external transfer students.

If external transfer students are denied admission to the Tickle College of Engineering, the student must contact Undergraduate Admissions to declare a new major for admission to UT.

Transfer Credit

Every attempt will be made to give maximum credit for courses taken elsewhere and transferred to the college. Discussions concerning the evaluation of transfer credits should be conducted with the Engineering Advising Office or the head of the department (or designee) into which the student is to transfer, but only after receiving the evaluation of transfer credits by the Office of Undergraduate Admissions Transfer Center.

Second Bachelor of Science Degree

Upon recommendation by the major engineering department and approval by the Dean of Engineering, a student who already holds a bachelor’s degree may obtain a degree in engineering upon meeting all of the course requirements of the selected engineering program. In no case will the minimum requirement be less than 30 semester credits. The prevailing university regulations shall apply.

University General Education Requirement

The University of Tennessee has established a University General Education Requirement that includes emphases upon building basic skills and developing broadened perspectives. These requirements apply to all undergraduate students and are listed in this catalog. Engineering students should consult with their advisor and carefully select General Education Electives to ensure that courses meet both the general education needs of their program and the University General Education Requirement.

American History Requirement

Engineering students, regardless of national origin, must fulfill the American history requirement described in the Academic Policies and Procedures section of this catalog. Those students who have not had the required year of American history in high school may choose the required 6 hours from HIUS 221 * and HIUS 222 *, or other courses deemed suitable by the Department of History. See additional information about the American History Requirement in the Academic Policies and Procedures  section of this catalog.

Technical Electives

Technical electives are to be selected with the advice and approval of the student’s major department. In some of the curricula showcases, a choice of such electives is indicated and regulations in regard to their selection are stated.

The Voluntary ROTC Program

Engineering students may participate in the ROTC Program. Subject to approval by the student’s academic advisor, advanced ROTC courses (300- and 400-series) may be counted as technical elective credit toward an engineering degree up to a total of 6 hours.

Approval of Electives and Substitutions

Each student shall discuss with an advisor the status of the program of study no later than the beginning of the second semester prior to anticipated graduation. Any necessary additions to or substitutions in the program or electives requiring special approval must be approved in writing at that time. It is each student’s responsibility to see that all necessary approvals are secured. Inattention to such matters will most likely delay graduation.

Curricula

Course requirements for the various engineering curricula are listed in each department’s section. Individual course prerequisites should be strictly adhered to, even if courses are not taken in the semester indicated. Although the requirements for each major can be completed in four academic years (five for the cooperative program), the quality of the learning experience is much more important than the speed with which the curricula are completed.

Questions about individual courses should be directed to the department responsible for the course. Questions about a particular curriculum should be directed to the major department or the Engineering Advising Office.

Prerequisites

Before registering for any engineering course, a student should make certain that any necessary background work has been completed. In addition to specific prerequisites listed, it is assumed that a student taking sophomore engineering courses has completed all freshman courses, whether specifically listed as a prerequisite or not. When this is not the case, a student should seek advice from the advisor or department responsible for the course in question before registration in order to minimize the chances of academic difficulty. Students who do not have prescribed prerequisites may be dropped from a course at any time during a semester when the lack of prerequisites is discovered.

Probation and Dismissal Procedures

Academic Probation in Engineering

The university will review students having academic difficulty and on academic probation the week after final grades are posted. The university academic probation policy is stated in the Academic Policies and Procedures  section of this catalog.

Dismissal from Engineering

Students dismissed from the Tickle College of Engineering and/or the University of Tennessee, Knoxville, will be removed from all courses if pre-registered for the following term. Dismissed students must follow university policies and procedures regarding academic dismissal and readmission as stated in the Academic Policies and Procedures and Admission to the University sections in this catalog. Dismissed students may no longer pursue a major in the Tickle College of Engineering.

Five-Year BS/MS with Physics Minor

Qualified students completing a BS degree from a department of the Tickle College of Engineering or the College of Arts and Sciences may add a physics minor by completing the requirements listed below. Six hours of 400-level courses required for a minor in physics combined with a BS engineering degree may be applied toward a master’s degree (project option or non-thesis option) in physics during a fifth year following the award of the BS. This program is designed for students attending the University of Tennessee for their Master of Science degree because other universities may not accept these courses for graduate credit since they were used to satisfy requirements for an undergraduate program. Significant components of the program are:

  • Students must have an overall GPA of 3.4 in required coursework. Conditional admission may be granted after completing the required 100- and 200-level requirements for the minor while full admission is granted after enrolling in the final semester of courses required for all BS and minor course requirements with a minimum overall GPA of 3.4.
  • Students must at least be conditionally admitted to the program prior to taking graduate courses for both their minor and master’s degree. All courses taken for graduate credit must be approved by the graduate program director. Students admitted to the program must request permission from the Graduate School to take approved courses for graduate credit.
  • Students admitted to the program must also follow the normal procedure for admission to the Graduate School. Admission of students into this program must be approved by the department and the Graduate School. Students will not be eligible for assistantships until they are enrolled as graduate-level students in the Graduate School.

VolsTeach Program

Students pursuing a major in the Tickle College of Engineering are eligible to participate in the University’s VolsTeach program (https://volsteach.utk.edu/), which permits students to simultaneously complete a major in engineering and receive secondary education teaching licensure through completion of a VolsTeach minor. For more information about VolsTeach, including advising associated with teaching licensure requirements, contact the Center for Enhancing Education in Mathematics and Science (101 Greve Hall).

uTrack Requirements

Universal Tracking (uTrack) is an academic monitoring system designed to help students stay on track for timely graduation. In order to remain on track, students must complete the minimum requirements for each tracking semester, known as milestones. Milestones include successful completion of specified courses and/or attainment of a minimum GPA. uTrack requirements only affect full-time, degree-seeking students who first entered Fall 2013 or later. uTrack does not apply to transfer students who entered prior to Fall 2015.

Academic Programs