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The Acknowledgments long road culminating in this dissertation could not have been successfully traveled without the help of numerous people. First, I d like to thank my committee, Drs. Richey Davis, Kim Forsten, Eva Marand, and Allan Shultz, for helpful comments, and my advisor, Dr. Tom Ward, for patience and guidance throughout the process. Several people helped with various aspects of the experiemental work. Dr Anita Hill, of CSIRO Australia, collaborated on the oligomer blend work. Dr. David Shelby of Eastman Chemical was instrumental in obtaining some results which satisfied the terms of the supporting grant. Kim Harich put in a significant effort to obtain MALDI-TOF results for this system, while Dave Williamson ran the TGA-MS tests. Dave Godshall lent assistance with the IR analysis, among other things. Drs. Shobha and Kim were invaluable with their running of the GPC experiments. I also want to especially thank TA Instruments, particularly Dr. Steve Aubuchon and Sujan Bin Wadud for going well beyond the call of duty by loaning instruments and in general enabling collection of data. Thanks also go to the PolyPkem research group, both past and present, for support and encouragement, both in and out of the lab, and for helpful discussion about research and life. Special thanks go to Dave Porter for help with the degradation chamber, to Dr. Mark Muggli and Dr. Kermit Kwan for answering some of my questions, and to the present members of the group: Catherine Beck, Amy Eichstadt, Rebecca Fall, Sandra Henderson, Emmett O Brien, and Jianli Wang. You guys made all the hard work a pleasure. Thanks are also due to the secretaries who quietly keep everything running smoothly: Esther Brann, Laurie Good, Millie Ryan, Diane Cannaday, Chris Moore, and Sandy Simpkins. Without these ladies, the departments would surely fall apart! I d also like to extend my appreciation to the guys in the Physics Machine Shop and Electronics Shop who have, in various ways, helped invaluably throughout this whole process. Finally, and most importantly, I want to thank my family for all their love, encouragement, and support through this long journey. Thanks to Mom, Dad, and Gamma for their frequent trips to Blacksburg to help me retain my sanity. Thanks to Jason and Laura for always being there to talk, to listen, and generally to be the best brother and sister (-in-law) around. And especially to Lydia, to whom this effort is dedicated, for bringing such joy into all our lives. iii Table of Contents 1. Literature Review of Structural Features .................................................................... 1 1.1. Introduction ............................................................................................................. 1 1.2. Molecular Weight Distribution Superposition ........................................................ 2 1.3. Chemistry ................................................................................................................ 8 1.4. Kinetics.................................................................................................................. 25 2. Literature Review of Properties ................................................................................ 55 2.1. Rheology ............................................................................................................... 55 2.2. Material Properties ................................................................................................ 67 3. Kinetic Studies .......................................................................................................... 78 3.1 Introduction ........................................................................................................... 78 3.2 Experimental ......................................................................................................... 79 3.3 Discussion ............................................................................................................. 80 3.3.1. Isothermal Results ............................................................................................. 80 3.3.2. Dynamic Methods ............................................................................................. 92 3.4 Summary ................................................................................................................... 110 4. Structural Features................................................................................................... 111 4.1 Introduction ......................................................................................................... 111 4.2 Degradation Conditions....................................................................................... 113 4.3 Chemistry ............................................................................................................ 117 4.3.1 4.3.2 TGA-MS...................................................................................................... 117 FTIR ............................................................................................................ 120 4.4 Molecular Weight Distribution ........................................................................... 127 iv 4.4.1 GPC Results ................................................................................................ 127 4.4.2 Molecular Weight Analysis......................................................................... 132 4.4.3 5. MWD Superposition ................................................................................... 138 Property Results ...................................................................................................... 143 5.1. Introduction ......................................................................................................... 143 5.2. Differential Scanning Calorimetry Measurements.............................................. 144 5.2.1. Tg Measurements......................................................................................... 144 5.2.2. Tg Prediction................................................................................................ 149 5.3. Mechanical Testing ............................................................................................. 157 5.3.1. Stress-Strain Measurements ........................................................................ 157 5.3.2. Tensile Strength Predictions........................................................................ 162 5.4. Rheology ............................................................................................................. 166 5.4.1. Viscosity Measurements ............................................................................. 166 5.4.2. Viscosity Predictions................................................................................... 177 5.5. Summary ............................................................................................................. 182 6. Conclusions and Future Work................................................................................. 183 Appendix A .186 v List of Figures Figure 1.2-1 Comparison of two samples with different thermal histories but similar values from Chan.2 ...................................................................................................... 8 Figure 1.3-1 Davis and Golden5,6,7 mechanism for polycarbonate degradation. .............. 12 Figure 1.3-2 Lee s8 degradation mechanism for PC degradation from 300-320 C.......... 13 Figure 1.3-3 Lee s8 degradation mechanism for 340-380 C. ........................................... 14 Figure 1.3-4 Kuroda s9 reaction scheme for polycarbonate degradation.......................... 15 Figure 1.3-5 McNeill and Rincon s10,11 Scheme I for polycarbonate degradation. .......... 17 Figure 1.3-6 McNeill and Rincon s10,11 Scheme II for polycarbonate degradation. ........ 18 Figure 1.3-7 McNeill and Rincon s10,11 Scheme III for polycarbonate degradation......... 19 Figure 1.3-8 McNeill and Rincon s10,11 Scheme IV for polycarbonate degradation. ....... 20 Figure 1.3-9 Montaudo and Puglisi s12,13,14 Scheme I for polycarbonate degradation. .... 22 Figure 1.3-10 Montaudo and Puglisi s12,13,14 Scheme II for polycarbonate degradation. . 23 Figure 1.4-1 Variable heating rate thermogram for Teflon.42 ........................................... 38 Figure 1.4-2 Illustration of Friedman s method.49 ............................................................ 42 Figure 1.4-3 Curves for graphical estimation of AR for Teflon at heating rates of 6 C/min and 18 C/min.52 ......................................................................................................... 44 Figure 1.4-4 Curves for graphical estimation of AW for Teflon at heating rates of 6 C/min and 18 C/min.52 ......................................................................................................... 44 Figure 1.4-5 Theoretical plots of reaction order n versus S1/S2 for various values of W1/W2 or W1,c/W2,c and WR.42 .................................................................................. 46 Figure 2.1-1 Storage master curve at a reference temperature of 275 C for various polycarbonate samples.1 ............................................................................................ 58 vi Figure 2.1-2 Experimental viscosity data and viscosity model for polycarbonate.1 ......... 59 Figure 2.1-3 Comparison of the viscosity model predictions to the viscosity data of polycarbonate.1 .......................................................................................................... 60 Figure 2.1-4 Influence of polydispersity on the shape of the viscosity curve. Squares represent a polydispersity of 3.0, circles are 2.6.1 ..................................................... 61 Figure 2.1-5 Viscosity versus molecular weight for polystyrene fractions.6 .................... 62 Figure 2.2-1 Stress versus molecular weight in the brittle region. Squares represent a strain rate of 1 min-1, triangles a rate of 0.0001 min-1.26 ........................................... 72 Figure 2.2-2 Stress versus strain for molecular weights ranging from 5300-21,900 and at various strain rates.26 ................................................................................................. 72 Figure 3.3.1-1 Raw data for laboratory grade polycarbonate, PC(Lab)............................ 82 Figure 3.3.1-2 Raw data for Lexan polycarbonate, PC(Lex). ......................................... 83 Figure 3.3.1-3 Kinetic master curve for PC(Lab). ............................................................ 83 Figure 3.3.1-4 Master curve for PC(Lex).......................................................................... 84 Figure 3.3.1-5 Fits to Eqn. 3.3.1-1 for PC(Lab) at isothermal temperatures of (a) 375 C; (b) 387.5 C; (c) 400 C; (d) 425 C. ........................................................................... 85 Figure 3.3.1-6 Fits to Eqn. 3.3.1-1 for PC(Lex) at isothermal temperatures of (a) 375 C; (b) 387.5 C; (c) 400 C; (d) 425 C. ........................................................................... 86 Figure 3.3.1-7 Arrhenius analysis for PC(Lab) degradation............................................. 87 Figure 3.3.1-8 Arrhenius analysis for PC(Lex) degradation............................................. 88 Figure 3.3.1-9 Klaric s method applied to PC(Lex).......................................................... 89 Figure 3.3.1-10 Klaric s method applied to PC(Lab)........................................................ 90 Figure 3.3.1-11 Derivative curves for PC(Lab). ............................................................... 90 vii Figure 3.3.1-12 MacCallum and Schoff s method applied to PC(Lex). ........................... 91 Figure 3.3.1-13 MacCallum s method applied to both PC grades: (a) and (b) PC(Lab); (c) and (d) PC(Lex)......................................................................................................... 92 Figure 3.3.2-1 Results of the Freeman-Carroll method for: (a) and (b) PC(Lab); and (c) and (d) PC(Lex)......................................................................................................... 95 Figure 3.3.2-2 PC(Lab) analyzed according to the method of Van Krevelen................... 97 Figure 3.3.2-3 PC(Lex) analyzed according to the method of Van Krevelen................... 97 Figure 3.3.2-4 PC(Lab) analyzed according to the method of Horowitz and Metzger..... 98 Figure 3.3.2-5 PC(Lex) analyzed according to the method of Horowitz and Metzger..... 99 Figure 3.3.2-6 Application of Friedman s method to: (a) and (b) PC(Lab); and (c) and (d) PC(Lex). .................................................................................................................. 100 Figure 3.3.2-7 Reich s method applied to PC. (a) and (b): AR and AW for PC(Lab); (c) and (d): AR and AW for PC(Lex); (e) linear fit for PC(Lab); (f) linear fit for PC(Lex). ................................................................................................................................. 102 Figure 3.3.2-8 PC(Lab) as plotted via Ozawa s technique. ............................................ 105 Figure 3.3.2-9 PC(Lex) as plotted via Ozawa s technique. ............................................ 105 Figure 3.3.2-10 Flynn s procedure applied to: (a) and (b) PC(Lab); and (c) and (d) PC(Lex). .................................................................................................................. 107 Figure 3.3.2-11 Coats and Redfern s method applied to PC(Lab).................................. 108 Figure 3.3.2-12 Coats and Redfern s method applied to PC(Lex).................................. 108 Figure 3.3.2-13 PC(Lab) analyzed according to Tagle s method. .................................. 109 Figure 3.3.2-14 PC(Lex) analyzed according to Tagle s method. .................................. 110 viii Figure 4.3.1-1Schematic representation of the degradation chamber utilized in this study. ................................................................................................................................. 115 Figure 4.3.1-2 Thermal lag for isotherms during degradation in oven. Solid line Solid represents 300 C, the temperature below which no degradation occurs. symbols indicate to the oven temperature, open symbols to the sample................. 116 Figure 4.3.1-1Mass spectrum for PC(Lab)...................................................................... 121 Figure 4.3.1-2 Mass spectra for PC(Lex)........................................................................ 121 Figure 4.3.2-1 Infrared spectra for PC(Lab). .................................................................. 123 Figure 4.3.2-2 Infrared spectra for PC(Lex). .................................................................. 123 Figure 4.3.2-3 FTIR results for PC(Lab) in the region of the 771 cm-1 peak. ................ 125 Figure 4.3.2-4 FTIR results for PC(Lex) in the region of the 771 cm-1 peak. ................ 125 Figure 4.3.2-5 C=O stretching region of the spectra for PC(Lab). ................................. 126 Figure 4.3.2-6 C=O stretching region of the spectra PC(Lex). for ................................. 127 Figure 4.3.2-7 C-H stretching region for PC(Lab).......................................................... 128 Figure 4.3.2-8 C-H stretching region for PC(Lex).......................................................... 128 Figure 4.4.1-1 Molecular weight distribution for PC(Lab)............................................. 131 Figure 4.4.1-2 Molecular weight distributions for PC(Lab) degraded at 325 C for the times indicated......................................................................................................... 132 Figure 4.4.1-3 Molecular weight distributions for PC(Lab) degraded at 350 C for the times indicated......................................................................................................... 132 Figure 4.4.1-4 Molecular weight distributions for PC(Lab) degraded at 375 C for the times indicated......................................................................................................... 133 ix Figure 4.4.1-5 Molecular weight distributions for PC(Lab) degraded at 400 C for the times indicated......................................................................................................... 133 Figure 4.4.1-6 Molecular weight distributions for PC(Lex). .......................................... 134 Figure 4.4.2-1 Influence of exposure time on weight average molecular weight for PC(Lab). .................................................................................................................. 137 Figure 4.4.2-2 Influence of exposure time on weight average molecular weight for PC(Lex). .................................................................................................................. 137 Figure 4.4.2-3 Influence of exposure time on weight average molecular weight for PC(Lab). .................................................................................................................. 138 Figure 4.4.2-4 Influence of exposure time on number average molecular weight for PC(Lab). .................................................................................................................. 138 Figure 4.4.2-5 Influence of exposure time on weight average molecular weight for PC(Lex). .................................................................................................................. 139 Figure 4.4.2-6 Influence of exposure time on number average molecular weight for PC(Lex). .................................................................................................................. 140 Figure 4.4.3-1 Comparison of molecular weight distributions for samples with similar values....................................................................................................................... 141 Figure 4.4.3-2 Comparison of molecular weight distributions for samples with similar values....................................................................................................................... 142 Figure 4.4.3-3 Comparison of molecular weight distributions for samples with similar values....................................................................................................................... 142 Figure 4.4.3-4 Molecular weight distribution master curve for PC(Lab). ...................... 144 Figure 5.2.1-1DSC thermograms for PC(Lab) degraded at 325 C. ................................ 147 x Figure 5.2.1-2 DSC thermograms for PC(Lab) degraded at 350 C. ............................... 148 Figure 5.2.1-3 DSC thermograms for PC(Lab) degraded at 375 C. ............................... 148 Figure 5.2.1-4 DSC thermograms for PC(Lab) degraded at 400 C. ............................... 149 Figure 5.2.1-5 DSC thermograms for PC(Lex)............................................................... 149 Figure 5.2.2-1 Relationship between Tg and for PC(Lab)............................................ 152 Figure 5.2.2-2 Relationship between Tg and for PC(Lex)............................................ 152 Figure 5.2.2-3 Relationship between Tg and reciprocal molecular weight for PC(Lab). 153 Figure 5.2.2-4 Relationship between Tg and reciprocal molecular weight for PC(Lex). 154 Figure 5.2.2-5 Ogawa s relationship applied to PC(Lab). .............................................. 155 Figure 5.2.2-6 Fox-Loshaek fit of DSC data for PC(Lab). ............................................. 156 Figure 5.2.2-7 Dobkowski s model, utilizing number average molecular weight, applied to DSC data from PC(Lab)...................................................................................... 157 Figure 5.2.2-8 Dobkowski s model, utilizing weight average molecular weight, applied to DSC data from PC(Lab).......................................................................................... 158 Figure 5.2.2-9 Bicerano s model applied to the DSC data for PC(Lab). ........................ 159 Figure 5.3.1-1 Comparison of stress-strain results for the PC samples indicated. Curves are displaced from 0% strain for clarity. ................................................................. 160 Figure 5.3.1-2 Effect of thermal history on tensile strength for PC(Lab)....................... 162 Figure 5.3.1-3 Effect of thermal history on modulus for PC(Lab). ................................ 162 Figure 5.3.1-4 Effect of thermal history on toughness for PC(Lab). .............................. 163 Figure 5.3.2-1 Flory s model (Equation 5.2.2-3) applied to tensile strength data for PC(Lab). .................................................................................................................. 165 Figure 5.3.2-2 Ogawa s model applied to tensile strength data for PC(Lab).................. 166 xi Figure 5.3.2-3 Dobkowski s model, utilizing number average molecular weight, applied to tensile strength data for PC(Lab). ....................................................................... 167 Figure 5.3.2-4 Dobkowski s method, utilizing weight average molecular weight, applied to tensile strength data for PC(Lab). ....................................................................... 167 Figure 5.4.1-1 Master curve for PC(Lab) showing increase in * at low frequencies. This sample has = 0 (no degradation)........................................................................... 170 Figure 5.4.1-2 Effect of thermal history on zero shear rate viscosity for PC(Lab)......... 170 Figure 5.4.1-3 Master curves for PC(Lab) degraded at 325 C. ...................................... 172 Figure 5.4.1-4 Horizontal shift factors for PC(Lab) degraded at 325 C......................... 172 Figure 5.4.1-5 Vertical shift factors for PC(Lab) degraded at 325 C. ............................ 173 Figure 5.4.1-6 Master curves for PC(Lab) degraded at 350 C. ...................................... 173 Figure 5.4.1-7 Horizontal shift factors for PC(Lab) degraded at 350 C......................... 174 Figure 5.4.1-8 Vertical shift factors for PC(Lab) degraded at 350 C. ............................ 174 Figure 5.4.1-9 Master curves for PC(Lab) degraded at 375 C. ...................................... 175 Figure 5.4.1-10 Horizontal shift factors for PC(Lab) degraded at 375 C....................... 175 Figure 5.4.1-11 Vertical shift factors for PC(Lab) degraded at 375 C. .......................... 176 Figure 5.4.1-12 Master curves for PC(Lab) degraded at 400 C. .................................... 176 Figure 5.4.1-13 Horizontal shift factors for PC(Lab) degraded at 400 C....................... 177 Figure 5.4.1-14 Vertical shift factors for PC(Lab) degraded at 400 C. .......................... 177 Figure 5.4.1-15 Horizontal shift factors from all PC(Lab) samples modeled by the WLF expression................................................................................................................ 178 Figure 5.4.1-16 Vertical shift factors from all PC(Lab) samples modeled by the WLF expression................................................................................................................ 178 xii Figure 5.4.2-1 Richards and Jordan s model applied to PC(Lab) degraded at 350 C, 3 hr. ................................................................................................................................. 180 Figure 5.4.2-2 Relationship between relaxation times and degree of degradation for PC(Lab) samples. .................................................................................................... 180 Figure 5.4.2-3 Master curves for the indicated samples of PC(Lab). ............................. 182 Figure 5.4.2-4 Overall master curve for PC(Lab). .......................................................... 182 Figure 5.4.2-5 Horizontal shift factors, modeled by the WLF equation, for the overall master curve. ........................................................................................................... 183 Figure 5.4.2-6 Vertical shift factors, modeled by the WLF equation, for the overall master curve. ....................................................................................................................... 183 Figure 1 Materials used in this study. ............................................................................. 191 Figure 2 DSC scans of all blends indicating a single Tg and hence miscibility.............. 195 Figure 3 DMTA data for some of the blends demonstrating a single Tg and hence miscibility................................................................................................................ 196 Figure 4 Frequency sweeps for four of the blends at 290 C and 2% strain.................... 198 Figure 5 Zero-shear rate viscosity versus weight percent m-BPA for blends................. 199 Figure 6 Pycnometry data for the blends. Line drawn to indicate additivity. ................ 200 Figure 7 Fractional free volume calculated by group contribution method.................... 201 Figure 8 oPS pickoff lifetime 3, related to free volume cavity size, plotted as a function of composition for quenched and aged samples. Line drawn to indicate trend. .... 203 Figure 9 oPS pickoff intensity, I3, related to free volume concentration, plotted as a function of composition for quenched and aged samples. Lines drawn to indicate trends. ...................................................................................................................... 203 xiii Figure 10 oPS pickoff lifetime 3, related to free volume cavity size, plotted as a function of composition for dry, moisture saturated and intermediate samples.................... 204 Figure 11 oPS pickoff intensity, I3, related to free volume concentration, plotted as a function of composition for dry, moisture saturated, and intermediate samples. ... 204 Figure 12 Normalized oPS pickoff intensity for nylon-6 as a function of water absorption. Weight percent water absorption is normalized to percentage of saturation. ......... 206 Figure 13 Normalized oPS pickoff intensity data for nylon-6 as a function of water absorption. Weight percent water absorption is normalized to percentage of saturation. ................................................................................................................ 207 Figure 14 Water absorption results for PSF and blends.................................................. 208 Figure 15 Diffusivity of water in PSF and blends........................................................... 208 Figure 16 Comparison of the relationship between diffusivity and PALS free volume for water in PVOH39, acetone in PET/PEN copolymers40, and water in PSF/m-BPA blends. ..................................................................................................................... 210 Figure 17 Results of tensile testing for some of the blends. ........................................... 212 Figure 18 Aging data for 95/5 blend. .............................................................................. 213 xiv List of Tables Table 3.3.1-1 Calculated Reaction Rate Constants for PC(Lab)....................................... 85 Table 3.3.1-2 Calculated Reaction Rate Constants for PC(Lex)....................................... 86 Table 3.3.1-3 Summary of Results from Isothermal Methods.......................................... 92 Table 3.3.2-1 Summary of Results from Dynamic Analyses for both Polycarbonates .. 109 Table 4.2-1 Summary of Values................................................................................... 116 Table 4.4-1 Summary of Molecular Weight Data for All Samples ................................ 134 Table 5.2.1-1 Summary of DSC Results ......................................................................... 148 Table 5.3.1-1 Summary of Mechanical Results .............................................................. 162 Table 1 Oxidation and DSC Tg Results for Blends ........................................................ 196 Table 2 Humidity Absorption for Blends........................................................................ 204 Table 3 Aging Rate and Secondary Transition Results................................................... 211 xv List of Symbols * 0 0 [Pn] [R n] A A A1, A2 a2 AR a T, b T AW B C C1, C2 D Ea f G G g( ) Shear rate Slope of power law region T-Ts Tensile strength at infinite molecular weight Complex viscosity Polymer density Zero shear rate viscosity Concentration of polymer with chain length n Concentration of free radical with chain length n 3.4 Constant Pre-exponential factor Constants of a polynomial Polydispersity exponent Area between the curves (ln reaction rate versus T) for two heating rates Shift factors Area between the curves (ln weight versus T) for two heating rates Constant Constant Williams-Landel-Ferry constants Characteristic relaxation time Constant Degree of degradation Activation energy Fractional conversion Fractional conversion Frequency Shear loss modulus Shear storage modulus Function defined as GN0 H( ) I J(z) K k K , K M m0 0 f ( ) d Plateau modulus Normalized relaxation spectrum Heating rate W 0 W dW Wn Tabulated quantity Constant Reaction rate constant Constants Polymer molecular weight Monomer molecular weight Number average molecular weight, Mn Mc Me MT ni Mi ni Critical (entanglement) molecular weight Molecular weight between entanglements Threshold molecular weight, Mc1.5 xvi Mw Mv n P P q r R Rt RT S Weight average molecular weight, n i M 2i ni Mi Viscosity average molecular weight Order of reaction Property Property at infinite molecular weight Polydispersity Chain length Gas constant Relative mass of sample residue d /dt d /dT dWc 1 d T Stationary point at maximum of thermogram Tabulated quantity Vogel temperature Time where = 0.5 Tensile strength Glass transition temperature Tg at infinite molecular weight Temperature where the reaction rate is at a maximum Reduced time Temperature where W/W0 = 1/e Tensile strength Tensile strength at infinite molecular weight Maximum of the thermogram Weight of polymer Weight fraction of polymer with log M / S S(z) T t1/2 Tg Tg Tm tred Ts TS TS Vmax W Wn(log M) X c Y Zw Weight average chain length 0 1/ xvii

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ThesisReport_SS.pdf
Path: Virginia Tech >> LIB >> 05302007 Fall, 2008

Description: The Effect of Advance Demand Information on a Pull Production System with Two Customer Classes Sourish Sarkar Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University In partial fulfillment of the requirements leadi...

Back_Matter.pdf
Path: Virginia Tech >> LIB >> 12122000 Fall, 2008

Description: Curriculum Vitae James Luther Chamberlain III was born in Baton Rouge, Louisiana on 13 March 1956. He has been studying or working in forestry or forest products for more than 25 years. Jim has earned degrees in forestry, forest products marketing, f...

Ch_1_Introduction.pdf
Path: Virginia Tech >> LIB >> 12122000 Fall, 2008

Description: Managing National Forests for Non-Timber Forest Products Chapter 1 An Introduction to the Research Table of Contents 1. An Introduction to the Research . 1 1.1 1.2 1.3 1.4 1.4.1 1.4.2 1.4.3 1.5 1.6 1.7 Problem Statement . 2 Study Objectives .. 4...

Ch_2_NTFPs.pdf
Path: Virginia Tech >> LIB >> 12122000 Fall, 2008

Description: Managing National Forests for Non-Timber Forest Products Chapter 2 Non-Timber Forest Products An Overview of the Products and Markets Table of Contents 2. Non-Timber Forest Products: An overview of the products and markets . 1 2.1 2.1.1 2.1.2 2....

Ch_3_Plans.pdf
Path: Virginia Tech >> LIB >> 12122000 Fall, 2008

Description: Managing National Forests for Non-Timber Forest Products Chapter 3 Forest Management Plans and Management Perspectives Table of Contents 3. Forest Management Plans and Management Perspectives . 1 3.1 3.1.1 3.1.2 3.1.3 3.2 3.3 3.3.1 3.3.2 3.3.3 3...

Ch_4_Survey.pdf
Path: Virginia Tech >> LIB >> 12122000 Fall, 2008

Description: Managing National Forests for Non-Timber Forest Products Chapter 4 A Survey of Forest Managers Attitudes and Perceptions Table of Contents 4. A Survey of Forest Managers Attitudes and Perceptions. 1 4.1 4.1.2 4.1.3 4.2 4.2.2 4.2.3 4.2.4 4.2.5 4.2....

Ch_5_Case_Study.pdf
Path: Virginia Tech >> LIB >> 12122000 Fall, 2008

Description: Managing National Forests for Non-Timber Forest Products CHAPTER 5 A Case Study Analysis of Different Management Approaches Table of Contents 5. 5.1 5.2 A Case Study Analysis of Different Management Approaches . 1 Background .. 1 Research Approa...

Ch_6_Conclusion.pdf
Path: Virginia Tech >> LIB >> 12122000 Fall, 2008

Description: Managing National Forests for Non-Timber Forest Products Chapter 6 Conclusions and Implications Table of Contents 6. Conclusions and Implications . 1 6.1 6.2 6.3 6.4 6.5 6.6 Non-Timber Forest Products and National Forest Management . 1 Issues th...

etd.pdf
Path: Virginia Tech >> LIB >> 070199 Fall, 2008

Description: ANALYSIS OF THE TROPHIC SUPPORT CAPACITY OF SMITH MOUNTAIN LAKE, VIRGINIA, FOR PISCIVOROUS FISH Michael J. Cyterski Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requi...

thesis.pdf
Path: Virginia Tech >> LIB >> 05252000 Fall, 2008

Description: Phylogenetic Analysis of Iliamna (Malvaceae) Using the Internal Transcribed Spacer Region Tracey A. Bodo Slotta Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulllment of the requirements for ...

appA.pdf
Path: Virginia Tech >> LIB >> 1826102339 Fall, 2008

Description: Appendix A Table A.1 - Overview of JTPA and Related Studies (Listed in order cited in the Literature Review) STUDY Implementation of the Job Training Partnership Act: A Field Network Process Evaluation (Cook, 1986) PURPOSE A process study to examine ...

appBC.pdf
Path: Virginia Tech >> LIB >> 1826102339 Fall, 2008

Description: Appendix B Instructions and Guidelines for Virginia SDA Program Year 1995 JTPA Title II-A and C Job Training Plan Preparation I. II. Signature Page Identifying Information Complete the following information on the grant recipient and administrative e...

body.pdf
Path: Virginia Tech >> LIB >> 1826102339 Fall, 2008

Description: Chapter One Introduction A key objective of federally funded job training programs is to ensure that the workforce has the skills necessary to obtain and retain gainful employment. Today, the knowledge and skill needs of the workforce are growing ex...

etd.pdf
Path: Virginia Tech >> LIB >> 1826102339 Fall, 2008

Description: Programs on Paper: An Examination of Virginias Service Delivery Area Job Training Partnership Act Title II-A Job Training Plans Gwynnen Stokes Evans Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in parti...

JanelleCThesisFinal.pdf
Path: Virginia Tech >> LIB >> 09032003 Fall, 2008

Description: AN ASSESSMENT OF THE QUALITY OF AGRICULTURAL BEST MANAGEMENT PRACTICES IN THE JAMES RIVER BASIN OF VIRGINIA Janelle Hope Cunningham Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in the partial fulfillment ...

Thesis_Ravi.pdf
Path: Virginia Tech >> LIB >> 07312007 Fall, 2008

Description: Effects of Work Exposure on Maximum Acceptable Repetition Rates in a Manual Torquing Task Ravi Kant Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree...

LD5655.V855_1981.H958.pdf
Path: Virginia Tech >> LIB >> 09242008 Fall, 2008

Description: ...

JamieThesis.pdf
Path: Virginia Tech >> LIB >> 06222006 Fall, 2008

Description: Tolerance of Diversity, Collective Efficacy, and Criminal Victimization on a College Campus Jamie Lynn Spradlin Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for...

LD5655.V855_1966.H37.pdf
Path: Virginia Tech >> LIB >> 10302008 Fall, 2008

Description: ...

MarcoLopesPhD10-24-02.pdf
Path: Virginia Tech >> LIB >> 10222002 Fall, 2008

Description: HYDRATION OF COLONIC INGESTA AND FECES IN HORSES FED LARGE GRAIN MEALS OR TREATED WITH ENTERAL FLUID THERAPY, SALINE CATHARTICS AND INTRAVENOUS FLUID THERAPY by Marco A. F. Lopes Dissertation submitted to the Faculty of the Virginia Polytechnic Insti...

Guletd.pdf
Path: Virginia Tech >> LIB >> 32298 Fall, 2008

Description: A Behavioral and Educational Treatment to Improve Adolescent Mothers Supervision and Home Safety Practices With Their Young Children Charles S. Gulotta Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University...

nakles_thesis.pdf
Path: Virginia Tech >> LIB >> 07232004 Fall, 2008

Description: ETD-db: Item Temporarily Restricted This item has been taken ofine by Virginia Tech Library or Graduate School. This restriction is temporary, and the item will be automatically made available again shortly. For more information, contact Gail McMilla...

Kelleretd.pdf
Path: Virginia Tech >> LIB >> 040799 Fall, 2008

Description: DETERMINATION OF THE LEAK SIZE CRITICAL TO PACKAGE STERILITY MAINTENANCE by Scott W. Keller Dissertation submitted to the Faculty of Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of D...

LCarter_Dissertation_etd_v3.pdf
Path: Virginia Tech >> LIB >> 04252006 Fall, 2008

Description: Political Participation in a Digital Age: An Integrated Perspective on the Impacts of the Internet on Voter Turnout Lemuria D. Carter Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfil...

Dissertation.pdf
Path: Virginia Tech >> LIB >> 09252002 Fall, 2008

Description: ` Numerical Studies of the Jet Interaction Flowfield with a Main Jet and an Array of Smaller Jets Valerio Viti Dissertation Submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirement...

Vita.pdf
Path: Virginia Tech >> LIB >> 09252002 Fall, 2008

Description: Vita Valerio Viti Valerio grew up in a big place in a small village Italy. To pursue his studies in aeronautical sciences, he moved to a big city in the United Kingdom where he happily lived for a few years. During his undergraduate studies he studi...

1etd_dodd_0911.pdf
Path: Virginia Tech >> LIB >> 09202001 Fall, 2008

danette3.pdf
Path: Virginia Tech >> LIB >> 71198 Fall, 2008

Description: Marching Upward: The Role of the Military in Social Stratification and Mobility in American Society by Patricia Danette Light Dissertation submitted to the Faculty of Virginia Polytechnic Institute and State University in partial fulfillment of the...

FINAL.pdf
Path: Virginia Tech >> LIB >> 01082004 Fall, 2008

Description: RUFFED GROUSE (BONASA UMBELLUS) HABITAT ECOLOGY IN THE CENTRAL AND SOUTHERN APPALACHIANS Darroch M. Whitaker Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements ...

Abstract.txt
Path: Virginia Tech >> LIB >> 07262005 Fall, 2008

Description: Abstract A Self-Sustaining, Boundary-Layer-Adapted System for Terrain Exploration and Environmental Sampling This thesis describes the preliminary design of a system for remote terrain exploration and environmental sampling on worlds with dense atmos...

Figure8-Figure11.2005.08.09.txt
Path: Virginia Tech >> LIB >> 07262005 Fall, 2008

Description: From: Woods, Amy [Amy.Woods@thomson.com] Sent: Tuesday, August 09, 2005 7:27 AM To: \'mmorrow@vt.edu\' Subject: RE: Feedback (General Books Queries) from Corporate Website Dear Michael Morrow Further to your recent emails permission is granted for use ...

Figures9-10.txt
Path: Virginia Tech >> LIB >> 07262005 Fall, 2008

Description: From: Russ Davis [rdavis@ucsd.edu] Sent: Friday, July 08, 2005 6:31 PM To: mmorrow Subject: Figures Attachments: FIG2FIX.BMP; ATT00004.txt Mike, The copyrights for the figures belong to the IEEE and the Taylor & Francis Group. You could try to get th...

Thesis.pdf
Path: Virginia Tech >> LIB >> 07262005 Fall, 2008

Description: A Self-Sustaining, Boundary-Layer-Adapted System for Terrain Exploration and Environmental Sampling Michael Morrow Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University In partial fulllment of the requirements f...

arabicpages.pdf
Path: Virginia Tech >> LIB >> 02082005 Fall, 2008

Description: INVESTIGATION OF ULTIMATE BENDING STRENGTH OF STEEL BRACKET PLATES Chapter I INTRODUCTION 1.1 Overview A bracket plate is a moment connection used for gravity loads which act near a column, i.e. loads with a small moment arm, as shown in Figure 1.1...

etd.pdf
Path: Virginia Tech >> LIB >> 02082005 Fall, 2008

Description: INVESTIGATION OF ULTIMATE BENDING STRENGTH OF STEEL BRACKET PLATES by Benjamin Alan Mohr Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of MASTERS...

TITLErestored.pdf
Path: Virginia Tech >> LIB >> 11497 Fall, 2008

Description: DEVELOPMENT AND APPLICATIONS OF A FLAT TRIANGULAR ELEMENT FOR THIN LAMINATED SHELLS By P. Mohan A DISSERTATION SUBMITTED TO THE FACULTY OF VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE ...

AngelaLungerthesis.pdf
Path: Virginia Tech >> LIB >> 09292006 Fall, 2008

Description: Evaluation of organically certifiable alternate protein sources for production of the marine carnivore, cobia (Rachycentron canadum) Angela N. Lunger Virginia Polytechnic Institute and State University Virginia Maryland Regional College of Veterinary...

dissertation5.pdf
Path: Virginia Tech >> LIB >> 12112001 Fall, 2008

Description: CHRONIC SHEAR STRESS EFFECTS ON ENDOTHELIAL CELL RESPONSE by Selim Elhadj Chemical Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, VA Doctor of Philosophy In Chemical Engineering Approved: Kimberly E. Forsten...

thesis.pdf
Path: Virginia Tech >> LIB >> 07282002 Fall, 2008

Description: Optimal Experimental Designs for the Poisson Regression Model in Toxicity Studies Yanping Wang Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulllment of the requirements for the degree ...

Landon_Sego_dissertation.pdf
Path: Virginia Tech >> LIB >> 04122006 Fall, 2008

Description: Applications of Control Charts in Medicine and Epidemiology Landon H. Sego Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulllment of the requirements for the degree of Doctor of Philosop...

Neal_Dissertation.pdf
Path: Virginia Tech >> LIB >> 01102002 Fall, 2008

Description: Implementation of a Production Architecture For a Post-2000 Market: Demonstration of a Microfactory Concept by John Allen Neal, III Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillme...

danetd.pdf
Path: Virginia Tech >> LIB >> 041299 Fall, 2008

Description: Bulimic Symptomatology in College Women: To What Degree Are Hypnotizability, Dissociation, and Absorption of Relevance? Daniel I. Galper, M.S. Dissertation submitted to the Faculty of the Virginia Polytechnic Institute and State University in Parti...

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