# Register now to access 7 million high quality study materials (What's Course Hero?) Course Hero is the premier provider of high quality online educational resources. With millions of study documents, online tutors, digital flashcards and free courseware, Course Hero is helping students learn more efficiently and effectively. Whether you're interested in exploring new subjects or mastering key topics for your next exam, Course Hero has the tools you need to achieve your goals.

2 Pages

### sm5_24

Course: ME 465, Spring 2009
School: Norwich
Rating:

Word Count: 491

#### Document Preview

5.24 KNOWN: PROBLEM Initial and final temperatures of a niobium sphere. Diameter and properties of the sphere. Temperature of surroundings and/or gas flow, and convection coefficient associated with the flow. FIND: (a) Time required to cool the sphere exclusively by radiation, (b) Time required to cool the sphere exclusively by convection, (c) Combined effects of radiation and convection. SCHEMATIC: ASSUMPTIONS:...

Register Now

#### Unformatted Document Excerpt

Coursehero >> Vermont >> Norwich >> ME 465

Course Hero has millions of student submitted documents similar to the one
below including study guides, practice problems, reference materials, practice exams, textbook help and tutor support.

Course Hero has millions of student submitted documents similar to the one below including study guides, practice problems, reference materials, practice exams, textbook help and tutor support.
5.24 KNOWN: PROBLEM Initial and final temperatures of a niobium sphere. Diameter and properties of the sphere. Temperature of surroundings and/or gas flow, and convection coefficient associated with the flow. FIND: (a) Time required to cool the sphere exclusively by radiation, (b) Time required to cool the sphere exclusively by convection, (c) Combined effects of radiation and convection. SCHEMATIC: ASSUMPTIONS: (1) Uniform temperature at any time, (2) Negligible effect of holding mechanism on heat transfer, (3) Constant properties, (4) Radiation exchange is between a small surface and large surroundings. ANALYSIS: (a) If cooling is exclusively by radiation, the required time is determined from Eq. 3 2 (5.18). With V = D /6, As,r = D , and = 0.1, t= 8600 kg / m3 ( 290 J / kg K ) 0.01m 24 ( 0.1) 5.67 108 W / m 2 K 4 ( 298K ) 3 ln 298 + 573 298 + 1173 ln 298 573 298 1173 573 1 1173 +2 tan 1 tan 298 298 t = 6926s {1.153 0.519 + 2 (1.091 1.322 )} = 1190s If = 0.6, cooling is six times faster, in which case, ( = 0.1) < < t = 199s (b) If cooling is exclusively by convection, Eq. (5.5) yields ( = 0.6 ) 8600 kg / m3 ( 290 J / kg K ) 0.010m 875 ln = 275 1200 W / m 2 K t= cD T T ln i 6h Tf T t = 24.1s (c) With both radiation and convection, the temperature history may be obtained from Eq. (5.15). < D3 / 6 c ( ) dT 4 = D 2 h ( T T ) + T 4 Tsur dt ( ) Integrating numerically from Ti = 1173 K at t = 0 to T = 573K, we obtain t = 21.0s Continued .. < Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. other Any reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful. PROBLEM 5.24 (Cont.) Cooling times corresponding to representative changes in and h are tabulated as follows h(W/m K) | | t(s) | 2 200 0.6 21.0 200 1.0 19.4 20 0.6 102.8 500 0.6 9.1 For values of h representative of forced convection, the influence of radiation is secondary, even for a maximum possible emissivity of 1.0. Hence, to accelerate cooling, it is necessary to increase h. However, if cooling is by natural convection, radiation is significant. For a representative natural 2 convection coefficient of h = 20 W/m K, the radiation flux exceeds the convection flux at the surface of the sphere during early to intermediate stages of the transient. 70000 Heat fluxes (W/m ^2.K) 60000 50000 40000 30000 20000 10000 0 0 20 40 60 80 100 Cooling time (s) Convection flux (h=20 W/m^2.K) Radiation flux (eps=0.6) COMMENTS: (1) Even for h as large as 5...

Find millions of documents on Course Hero - Study Guides, Lecture Notes, Reference Materials, Practice Exams and more. Course Hero has millions of course specific materials providing students with the best way to expand their education.

Below is a small sample set of documents:

Norwich - ME - 465
PROBLEM 9.109KNOWN: Vertical array of circuit boards 0.15m high with maximum allowable uniform surface temperature for prescribed ambient air temperature. FIND: Allowable electrical power dissipation per board, q [ W / m ] , for these cooling arrang
Norwich - ME - 465
PROBLEM 4.39KNOWN: Nodal point configurations corresponding to a diagonal surface boundary subjected to a convection process and to the tip of a machine tool subjected to constant heat flux and convection cooling. FIND: Finite-difference equations f
Norwich - ME - 465
PROBLEM 2.37KNOWN: Temperature distribution in steam pipe insulation. FIND: Whether conditions are steady-state or transient. Manner in which heat flux and heat rate vary with radius. SCHEMATIC:ASSUMPTIONS: (1) One-dimensional conduction in r, (2)
Norwich - ME - 465
PROBLEM 4.54 KNOWN: Flue of square cross section with prescribed geometry, thermal conductivity and inner and outer surface temperatures. FIND: Heat loss per unit length from the flue, q. SCHEMATIC:ASSUMPTIONS: (1) Steady-state, two-dimensional con
Norwich - ME - 465
PROBLEM 1.25 KNOWN: Diameter and emissivity of spherical interplanetary probe. Power dissipation within probe. FIND: Probe surface temperature. SCHEMATIC:ASSUMPTIONS: (1) Steady-state conditions, (2) Negligible radiation incident on the probe. ANAL
Norwich - ME - 465
PROBLEM 9.56KNOWN: Dimensions and temperature of beer can in refrigerator compartment. FIND: Orientation which maximizes cooling rate. SCHEMATIC:ASSUMPTIONS: (1) End effects are negligible, (2) Compartment air is quiescent, (3) Constant properties
Norwich - ME - 465
PROBLEM 2.29 KNOWN: Steady-state temperature distribution in a one-dimensional wall of thermal 3 2 conductivity, T(x) = Ax + Bx + Cx + D. FIND: Expressions for the heat generation rate in the wall and the heat fluxes at the two wall faces (x = 0,L).
Lock Haven - CHEM - 320
Peter Atkins Julio de Paula Atkins' Physical ChemistryEighth EditionChapter 2 The First LawCopyright 2006 by Peter Atkins and Julio de Paula
Lock Haven - CHEM - 320
RememberthattheOttocycleproblemisdueFriday.itwill serveasthisweek'squiz.Title:Oct811:04AM(1of3)Title:Oct811:34AM(2of3)Title:Oct811:43AM(3of3)
Lock Haven - CHEM - 321
Name _CHEM 321 February 8, 2008 Quiz 2 (Take home) Be creative! In order to receive full credit you must show all of your work. Also be sure to use the correct number of significant figures and to indicate the units for your answer. For numerical p
Norwich - CH - 103
CHEMISTRY 103 SYLLABUSFALL 2008 Section: Instructor: Phone: E-mail: Web site: Lab site: A &amp; L1 B &amp; D &amp; L6 C &amp; E &amp; L4 J. RizzoloS238 S. FrisbieS132 M. HoppeS236 485-2356 485-2614 485-2353 rizzolo sfrisbie hoppe http:/www2.norwich.edu/hoppe/ch103 http:
Norwich - CH - 103
CHEMISTRY 103 SYLLABUSFALL 2002 Section: Instructor: Phone: E-mail: A J.RizzoloS238 485-2356 rizzolo B J.ByrneT177 485-2312 byrne C R.ButlerP226 485-2351 butler D M.McBrideS232 485-2354 mmcbride E M.HoppeS236 485-2353 hoppeINTRODUCTION CH 103 is th
Norwich - BI - 215
LABORATORY MANUAL FOR ANATOMY AND PHYSIOLOGYBy CARLOS F.A. PINKHAM, ROY D. BAIR, AND SCOTT L. PAGE INTRODUCTION TO LABORATORY PRACTICES Laboratory exercises will be accomplished in one to several ways: 1) as individuals; 2) as groups of two or three
Norwich - BI - 215
OUTLINE - INTRODUCTION Definitions Anatomy 1. 2. Physiology 1. 2. 3. Levels of Complexity 1.3 Anatomical Terminology Body Parts Axial Appendicular Points of Reference 2-2 Anatomical Position 1. Midline Sides Medial/Lateral Proximal/Distal Anterior/Po
Norwich - BI - 216
OUTLINE - BRIEF AND PROLONGED MOVEMENT BRIEF MOVEMENT brief - a short while, say 5 seconds - 1 minute Short-Term Chemistry 1. contraction of muscle requires energy - where from? 2. where is this ATP? OK, let's try it 3. clearly other sources needed,
Norwich - CH - 103
ChemActivity28A Chemical Reactions(How can chemical reactions be predicted and classified?)Model 1: Three Classifications of MatterThe easiest way to classify matter is by its physical state: solid, liquid, or gas. Most substances can exist in
Norwich - CH - 104
ChemActivity46SDE Solutions-Relative Acid StrengthSkill Development Exercises1. a) H 2 Se &gt; H 2 S due to the larger Se radius and weaker H-Se bond b) HONO &gt; HOPO due to the larger partial charge on the acidic hydrogen in the presence of the mor
Norwich - SEMINAR - 3
Lecture Three: Aspects of the International System Just as the economy of the United States was the worlds largest for most of the last century, the dollar has been the most important currency for international transactions and reserves, and capital
Norwich - SEMINAR - 3
Lecture 10: Resource Wars?Incentives, Opportunities, and ChallengesThe first two essays in this weeks session will, we hope, provoke a firestorm of debate. Mannings article suggest that there are direct economic consequences and impacts in how deve
Norwich - SEMINAR - 3
Lecture 5: Introduction the Debate; Realism, Economic Nationalism, and Mercantilism In what remains a seminal and immensely readable introduction to various worldviews (and their relationship to economics and the international system), Andrew Ross id
Norwich - SEMINAR - 3
Lecture Two: World Trade Relations The Nobel Prize-winning economist F. A. Hayek once suggested that economics as the study of the unintended consequences of human action. The understated elegance of this thought, nonetheless, does not mask the somet
Norwich - SEMINAR - 3
Economics and the International System Week 8: International Financial Networks &amp; Institutions -A View from the Developed World As we assess this block of readings, the Spero and Hart chapters (all optional reading, save Chapter 7) perhaps best demon
Norwich - SEMINAR - 3
Lecture 9: International Financial Networks &amp; Institutions A View from the Emerging World Rightly or wrongly, the view from the emerging world (what some variously refer to as the developing world or, incorrectly, the Third Worldwhich has no meaning,
Norwich - CH - 104
ChemActivity 26CApplications of Intermolecular Forces(How can we predict the properties of substances?)Model 1: A Review of Intermolecular ForcesMolecules in the gas phase are moving fast enough to remain far apart and not be attracted to each
Norwich - BI - 215
OUTLINE - TISSUES Problem 1. a. b. c. d. e. f. g. Solution 1. 2. 3. Types: Epithelial, Connective, Muscle, Nerve Epithelial Tissue Characteristics1. 2. 3. 4. 5. Classification 6-5, 5.1-5.3 &lt;tubes&gt; 5.5, 5.8, 5.9, &lt;packing material&gt;, 5.6 Properties T
Norwich - BI - 215
OUTLINE - TISSUES Problem 1. a. b. c. d. e. f. g. Solution 1. 2. 3. Types: Epithelial, Connective, Muscle, Nerve Epithelial Tissue Characteristics1. 2. 3. 4. 5. Classification 6-5, 5.1-5.3 &lt;tubes&gt; 5.5, 5.8, 5.9, &lt;packing material&gt;, 5.6 Properties T
Norwich - BI - 215
OUTLINE - THE CELL Introduction Where Are We? 1. 2. 3. 4. Types Shape Size 1. 2. 3. 4. 5. Major FeaturesBasics Interstitial Fluid 1. Intracellular Fluid 1. 2. Cell Membrane 1. 2. 4-4t, 4-4b Cell Membrane in Detail 1. 3.6, 3.7 2. &lt;balloon&gt;, 3.3 Comp
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Department Assistant Office of Human &amp; Cultural Diversity Kenneth Hall Academic Vice President Year Year Year Year 2007 - 2008 2007 200
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Classroom Technology Assistant - Main Campus School of Graduate Studies - PA Walt Eisenhauer Academic Vice President Year Year Year Yea
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Graduate Program Development Assistant Health and Physical Education Dr. Patricia Lally Academic Vice President Year Year Year Year 200
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Classroom Technology Assistant - CLFD Campus School of Graduate Studies - PA Walt Eisenhauer Academic Vice President Year Year Year Yea
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Intramural Sports Director Athletics Sharon Taylor/Brad Dally Athletics Year Year Year Year 2007 - 2008 2007 2007 2008 Grad Inter
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Assistant Lacrosse coach Athletics Kristen Selvage Academic Vice President Year Year Year Year 2007 - 2008 2007 2007 2008 Grad In
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Graduate Assistant/ Service-Learning Coord. Community Service Anne-Marie Turnage Student Affairs Year Year Year Year 2007 - 2008
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Counseling Service Graduate Assistant ADAC Dan Tess Academic Vice President Year Year Year Year 2007 - 2008 2007 2007 2008 Grad I
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Assistant Resident Director Student Life/Housing Department Dr. Dwayne L. Allison Housing Aux. Year Year Year Year 2007 - 2008 20
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Facility Operations Student Recreation Center Brad Dally Student Affairs Year Year Year Year 2007 - 2008 2007 2007 2008 Grad Inte
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Teaching and Learning Center Assistant Teaching and Learning Center Charles Jenkins Academic Vice President Year Year Year Year 2007 -
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring MLA and M.Ed Program Assistant School of Graduate Studies Charles Jenkins Academic Vice President Year Year Year Year 2007 - 2008 2006
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Graduate Intern Athletic Trainer #1 Health Science / Athletic Training Michael Porter Academic Vice President Year Year Year Year
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Student Activities Coordinator - Clearfield Clearfield Campus Clfd: Asst Director of Admissions/Campus Director Academic Vice Pre
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Women's Soccer Graduate Assistant Coach Athletic Department Heather Kendra Academic Vice President Year Year Year Year 2007 - 2008 2007
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Department Assistant School of Graduate Studies Dr. Nate Hosley Academic Vice President Year Year Year Year 2007 - 2008 2007 2007
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Assistant Coach, Men's Soccer Athletics Doug. Moore Academic Vice President Year Year Year Year 2007 - 2008 2007 2007 2008 Grad I
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring GA to the Coordinator of Women's Studies Women's Studies SueAnn Schatz Academic Vice President Year Year Year Year 2007 - 2008 20
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring Haven Achievers' Program Academic Development and CounselingDepartment Director of Haven Achievers' Program Academic Vice President Yea
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring eCampus Teaching and Learning Support eCampus Paddy O'Hara-Mays Academic Vice President Year Year Year Year 2007 - 2008 2007 2007
Lock Haven - POSITIONS - 06
Graduate Assistant Request FormPosition Title: Department: Supervisor: Funding Source: Academic Year Summer Fall Spring GA in Outdoor Recreation Recreation Management Dr. Steve Guthrie Academic Vice President Year Year Year Year 2007 - 2008 2007 200
Norwich - MA - 224
MA224 EXAM #2 SOLUTIONS 1. Consider the autonomous equation y = y(y 1)2 (y 2). (a) Determine the critical points. Solution. The critical points are y = 0, y = 1, and y = 2. (b) Sketch by hand graphs of solutions starting at initial values of y in e
Norwich - CH - 104
ChemActivity 81Polymers (II)(Composition of some common polymers)Model 1: Polymerization ReactionsPolymers can be classified by the reactions used to produce them. Addition polymers such as polyethylene, polypropylene, and polyvinyl chloride ar
Norwich - CH - 103
ChemActivity14Solutions - Bond Order and Bond StrengthExercises1. 2. 3. 4. The C=C (double bond) is harder to break. The C/C (triple bond) is harder to break. The C/N (triple bond) is stronger. Each pair of electrons shared between two atoms co
Norwich - MA - 224
MA224 EXAM #3 SOLUTIONS 1. Solve the linear second-order dierential equation y + 2y + y = sin 3t. Solution. The complementary equation is y + 2y + y = 0. This has characteristic equation r2 + 2r + 1 = 0 = (r + 1)2 = 0. Thus r = 1 is a double root and
Norwich - CH - 103
ChemActivity16Solutions - Lewis Structures (III)Exercises1.There is a misprint in your ChemActivity book. The third molecule is listed as CH 3 COOH. The atoms in this molecule have no formal charges and the Lewis structure should have been dr
Norwich - MA - 224
MA224 QUIZ #7 SOLUTIONS In all problems, consider a spring suspended from a ceiling. We attach a mass of 2 kg to the spring, which has a spring constant of 5 N/m. After the spring and mass have settled into equilibrium, we pull the spring downward by
Norwich - MA - 407
MA407 TAKE-HOME EXAM #1 SOLUTIONS 1. Sketch the vector eld F(x, y) = yi + j. Solution. All of the vectors point upward since the j-component is positive. They point to the right above the x-axis and to the left below it; they point directly up along
Norwich - CH - 104
ChemActivity 51AFaraday's Law(Can we force non-spontaneous chemical reactions to happen?)Model: Schematic of an Electrolytic CellInformationThe electrochemical cells we discussed in ChemActivities 50 and 51 have one thing in common: They all
Norwich - CH - 103
ChemActivity3Solutions - Coulombic Potential EnergyExercises1. IE = + 5.47 x 10-18 J since the ionization energy is equal in magnitude and opposite in charge to the potential energy of the atom. 2.IE a &gt; IE bNote that system a has an IE fou
Norwich - SEMINAR - 4
September 2007 Week 4. Conflict avoidance - interstate. Case study. Lecture (Reminder: the first paper is due at the end of this week. As noted in the syllabus the paper should be 7-10 pages of original research the genesis of an intrastate conflict.
Norwich - SEMINAR - 4
September 2007 Week 11. Multilateral Diplomacy and Unresolved Issues Regarding Peacekeeping Operations Lecture The readings for Week 11 make important points that serve as useful complements to the earlier readings and set the stage for the transitio
Norwich - SEMINAR - 4
This presentation is designed to give the students a brief review of the background of the Kashmir crisis.1As this map indicates Kashmir is located in the indicates, triangle between China, India and Pakistan. Although the most critical tensions
Norwich - SEMINAR - 4
September 2007 Week 5. Peacekeeping, Peacemaking and Peace Enforcement Lecture The United Nations has undertaken peacekeeping responsibilities for many decades. Indeed some peacekeeping missions have been in continuous operation for more than four de