Free Essay

Mechanical Properties of Ps Injected Parts Under Surface-Active Substances

In: Science

Submitted By dechispas
Words 2565
Pages 11
Mechanical properties of PS injected parts under surface-active substances

Journal: Manuscript ID: Division or Special Interest Group: Presentation Preference: Paper Type: Date Submitted by the Author: Complete List of Authors:

Page 1 of 5

MECHANICAL PROPERTIES OF PS INJECTED PARTS UNDER SURFACEACTIVE SUBSTANCES
(1)

The main objective of this work was to develop the influence of surface-active substances in the mechanical properties of injected plastic parts in presence of cracks, a tension test and a constant load. The material used was Polystyrene and the surface-active substances were olive oil and corporal sweat. This study was conducted because it was observed that the surface-active substances affects the mechanical properties of the resin as well as the presence of cracks, and actually is not reported any methodology for conducting this study.

Experimental Part
For this study, there were injected 110.5*85.5*1 mm plates in a REED-Prentice 100 TE (Clamp Force = 100 ton) injection machine with an injection mold with two similar cavities, but with a different located entrance. The used material was a Polystyrene PS-2820 from Estirenos del Zulia (Table 1). In table 2 are showed the used optimal process conditions. Notches were mechanized in each plate with a saw. The normalized tensile test specimens were cut with a milling machine. It was used a Galdabini 2500 universal test machine to make mechanical tests, and a Starrett Sigma VB300 stereoscopic magnifying glass to verify the crack length. To study the crack surface it was used a Macro Magnifying glass Olympus SZ61. To study the orientation and the stress concentrator in the plaques it was used a polaryscope Photoelastic Inc. 082.

Introduction
Since long time ago, the fracture has been a serious problem for the use of all materials. The fracture may be described how any change of the material properties that make the part functional or structural unacceptable. Nowadays, it is necessary to know and understand why the defects occur and to find the way to avoid them. The polymers are particularly sensitive to its processing. They are affected by environment, time, and temperature storage, shipping and service. Additionally, the plastic parts with geometric changes, holes and cracks in their structures have many stress concentrators that may induce them to an early failure during its use. Polymers failures may occur at low stress levels caused by a creep test, fatigue and liquid environmental agents. When a polymer is exposed to a chemical environment and simultaneously to a stress, it is observed a drastic fracture time reduction. Such agents do not attack the polymers molecules chemistry. They are not also solvents able to dissolve, however, they penetrate superficially the part, allowing the release of freeze stress and superficial rupture. This kind of failure has been called Environmental Stress Cracking (ESC) and it should be under consideration, since 20% of the plastic parts failures are caused by them. That is the reason why, the main purpose of this work is to develop a methodology that allows studying the influence of the surface-active substances over mechanical properties of injected PS parts. Previous works, for example, Kramer

Results and Discussion
This study came from a discovery made by Candal et al [5], where it was found that corporal sweat may act as an surface-active substance when interact with PS, affecting the results of the mechanical tests. Nowadays, there are several plastic parts (CD boxes, table settings, glasses, trays, tool boxes) that may be in contact with corporal sweat. Since there are not previous studies regarding this subject, the following methodology was design: 1. It was chosen a type of specimen to use: it was important to have a plaque able to modify the crack length in order to study the crack’s effect over the mechanical properties of plastic parts. Likewise, it was decided to use a normalized tensile test specimen type IV to study the effect of a surface-active substance without incorporating the crack influence.

Page 2 of 5

2. Material selection: the material was selected to complete the study and to know the mechanical and rheological properties. In this case it was chosen a PS injection grade. 3. It was established an injection process window of the polymer: this window indicates the temperature and the pressure ranges in which the material may be process, in accordance with the needed design and aesthetic requirements (good surface appeal, complete transparency and no presence of flashes or sink marks). Starting from here, an optimal process condition was chosen. 4. Plaques injection: the most important effect of injection molding over the PS parts was the imposed orientation, causing mechanical properties changes. Moreover, in the post-molding stage, there is a tendency to accumulate residual stress that are the consequence under low cooling conditions, flow and imposed orientation that chains do not relax. These may cause hazes and fragile zones with a tendency of failure by crazes. It is important to underline that in the particular case of PS, when plaques were manipulated; it was necessary to wear latex gloves and due to the direct hand-touch contact with the part may cause an effect that negatively affects the mechanical properties of the PS [5]. From the plaques, the tensile test specimens were die-casted. 5. Qualitative evaluation of stress concentrators: injection molding is a very fast and non isothermal mechanism that has a radical cooling, which solidified the piece. The transparent parts (made by PS) manufactured under this process, when they are studied under polarized light, show a color pattern on the surface where it can be easily recognized. The injection point location, the melted polymer movement direction (meld lines) and the residual stress (Figure 1). These last ones will depend on the melted flow direction, the gate type and gradient temperature used in the mold cycle to make the material injection [6]. 6. Collection and application of surface-active substances methodology: it was decided to develop a methodology that allows collecting the substance. The corporal sweat collection was made fixing a natural latex plaque to another high adherence plaque and putting sterile gauze between latex and skin (Figure 2). The method needs a previous washed with alcohol and water skin area of 24 cm² in each collector plaque. It is possible to put several plaques in the same individual. There were used plaques in both sides of the back, following both scapular lines in order to make the test (Figure 3). The latex plaques were previous cut from non-lubricated preservatives. The corporal sweat collect may be made in two ways: (a) if the individual produce a big quantity of corporal sweat after physical exercise or (b) obtaining corporal sweat from the gaze by centrifugation. Since the obtained surface-active substance needs a lot of preparation and provides small quantities of substance, it was decided to choose an

equivalent environment to develop the method. There were several substances available to choose the most alike environment to corporal sweat and without radically affect PS (margarine, olive oil, and car oil). It was decided to use olive oil. Although olive oil has a completely different composition to corporal sweat, it represented the alternative with most alike viscosity and origin. It was made a test to verify that PS has a low mechanical resistance to olive oil. In this test, there were tested two normalized test specimens. One of them was in contact with the substance but the other one not. Both specimens were under the same pressure to guarantee, that substances were in contact with the specimen. After 30 minutes, it was observed that, the specimen in contact with the substance had a large quantity of small crazes all along the edge of the specimen neck. After 90 minutes, it was also observed that the crazes were located not only on the neck edge, but also in the lengthwise neck (Figure 4). 7. Simple-tensile tests: there were made tensile tests, at room temperature, to the four specimens (complete plaques with one and two notches, medium plaques with one crack and normalized tensile test specimen) (Figure 5). It was possible to evaluate the effect of the crack over the part from one crack plaques. It was decided to evaluate the double crack behavior, but this idea was rejected, because there were putting two stress concentrators in a fragile material, and cracks were propagated at different velocities. At the end, the cracks did not match up in the fracture zone. For that reason, they could not be considered as a valid result. Especially, for the one crack half plaque and the test specimen it is important to underline the place from where the whole plaque was taken (centre or side). That fact will define its behavior in the mechanical property tests. By other hand, the obtained result after studying the whole plaque with one crack was a sum of what happen in the centre of the plaque and in one of its edges, which is different depending on the flow type inside the cavity (extensional, shear, laminar, etc.) in accordance with Castany [7]. 8. The number of stress concentrator influence and the location of the injection point: it was made a study of the chosen injected test specimens from two different locations, in transverse and longitudinal manner to the previous notched plaque (Figure 6). The crack length vs load was charted. It was obtained that the necessary force to break the injected test specimens by the longitudinal flow gate, exceeds at least by five times the requested flow, to break the test specimens with transverse gate (Figure 7). 9. The injection process conditions influence: it was study the effect over the final properties of PS parts. When the melt temperature was modified, there were changes in the fluency of the material and in the stress concentrator patterns of the part.

Page 3 of 5

10. Behavior of the plaque in presence of different length cracks: for both studied geometries with cracks, it was made a study of the crack length effect over its final properties. It was obtained that the longest the crack length is, the less load is necessary to fracture it. 11. Plaque behavior in presence of a crack and a surfaceactive substance: the used method of surface-active substances application was the following: the specimens impregnated with olive oil selected with a cotton swab were set in a stub. In the small area of the test specimen neck was put a part of cotton to guaranty a surface uniform covering. A dropper that provided the same quantity of oil in each piece was use to try that all the test specimen were under the same conditions. A similar method was followed for the plaques, nevertheless, the central part of the surface was not covered with cotton because it was complicated and the beginning of the crack was left free to achieve better oil spread inside the material. For the corporal sweat case, the test specimens were covered with gazes and kept them inside hermetic containers to guarantee an effective contact and avoid that the substance do not evaporates. When the behavior of the complete plaques was evaluated in presence of a crack in front of surface-active substances at a short time of exposition (4 hours), it was found a failure that mainly occurred by the presence of the crack. While the time of exposition increase to 8 hours, it was possible to evaluate the substance effect. The cracks introduce more severe conditions to the test, because they act as stress concentrators making three-axial stress at the beginning of the crack. 12. Comparisons between olive oil and corporal sweat: it was notice that the corporal sweat generates a smaller decrease of the material properties when it is compare with olive oil. 13. Observation of the test specimen’s surface fractures: the PS behaves fragile, therefore, its fracture involves crack propagation in shorter periods of time, usually under low stress levels, when it is compare to the ductile crack behavior. In the case of a fragile crack, it spreads with little plastic deformation and once the propagation begins, the material is unable to stop it, producing a severe crack.

• The design methodology for the study of the crack effect and the surface/active substances over mechanical properties of PS injected parts generates good results and may be use to evaluate other polymers.

References
1. E. Kramer and R. Bubeck, “Growth kinetics of solvents crazes in glassy polymers”, Journal of Polymer Science: Polymer Physics Edition, 16 (7), 1195 (1978). 2.J. Yu, Y. Hu and E. Baer, “Effect of an environmental stress cracking agent on slow crack propagation of Polyethylene”, SPE’s ANTEC Proceedings (2003), 2947. 3. J. Arnold, “The use of flexural tests in the study of environmental stress cracking of polymers”, Polymer Engineering & Science 35 (2), 665 (1994). 4. R. Bubeck and C. Arends, “Environmental stress cracking in impact polystyrene”, Polymer Engineering and Science 21 (10), 624 (1981). 5. M. Candal, R. Morales, H. D´armas and H. Rojas, “Stress Concentration Evaluation in an Injected Commercial Piece using Computational Tools”, SPE´s ANTEC Proceedings (2005), 3385. 6. E. Thompson, "Thermal Stresses", en "Encyclopedia of Polymer Science & Engineering", H. Mark, N. Bikales, C. Overberger, J. Menges, (eds), Vol 16, John Wiley & Sons, Inc., USA, second edition. (1987). 7. J. Castany, “Inyección de termoplásticos amorfos y líneas de soldadura”, Revista de Plásticos Modernos, 75 (504), 596 (1998).

Acknowledges: the authors would like to thank
Inversiones Selva, Estirenos del Zulia, 3M Manufacturera, Laboratorio de Estudios de Superficies of the Universidad Simón Bolívar University (Venezuela) and Centro Catalán del Plástico (Spain) for their cooperation and support. Without them this work would not be possible. Also we would like to thank Fundación Carolina for the financial support to the Engineer Duarte to go Spain. Special thanks to Professor Marco Sabino and Engineer Hector Rojas, both from USB, for their cooperation in the methodology of this work.

Conclusions
• The olive oil and the corporal sweat radically decrease the final PS parts properties. • The one crack plaques and the tensile test specimen produced the best results to verify the surface-active substance effect and cracks over the final properties of PS parts.

Keywords: surface-active substances, crack, mechanical properties, injected plastic parts and load.
Table 1: Properties of PS-2820. Properties Value Unit MFI (200 ºC/ 5 Kg) 22 g/10 min Young Modulus 3500 MPa Rupture Stress 38 MPa Solid Density 1,05 g/cm3

Page 4 of 5

Table 2 Injection molding process conditions used. Condición Valor Hidraulic Pressure 1,7 MPa Hold Pressure 1,2 MPa Melt Temperature 225 ºC Injection Time 4,0 s Holding pressure time 8,0 s Cooling time 50,0 s Demolding Time 1,0 s Figure 3: Scapularis Lines

(a)

(b) Figure 4: PS normalized test specimens with olive oil.

Figure 1: Qualitative evaluation of stress concentrators.

(a)

(b)

(a) (c)

(b) Figure 2: Corporal sweat collection (a) Latex plaque and (b) Sterile gauze.

(d) Figure 5: Specimens used for the study (a) completed plaques with one notch; (b) completed plaque with two notches; (C) Half plaques with one notch and (d) tensile test specimen.

Page 5 of 5

(a) (b) Figure 6: Notch cut in the two types of inject plaques (a) Longitudinal and (b) Transversal position.

Figure 7: Load vs nominal crack length for the complete plaque-

Similar Documents

Free Essay

Good

...Industrial Technologies Program Steam Digest A compendium of articles from 2003 on the technical and financial benefits of steam efficiency, presented by stakeholders in the U.S. Department of Energy’s BestPractices Steam efforts Volume IV Compiled for the Industrial Technologies Program By the Alliance to Save Energy Acknowledgements The Steam Digest: Volume IV is the fourth annual compilation of articles dedicated to steam system efficiency. The U.S. Department of Energy’s (DOE) Office of Energy Efficiency and Renewable Energy sponsors the BestPractices Steam program, which either directly or indirectly facilitated the creation of all the articles contained in this volume. BestPractices Steam, which is part of the wider BestPractices program under DOE’s Industrial Technologies Program, works with industry to identify plant-wide opportunities for energy savings and process efficiency. The BestPractices Steam Steering Committee provides a great deal of input and guidance into the program (see more information about the Committee on pages 1 and 2). Mr. Fred Fendt, Technical Fellow with Rohm & Haas, serves as Chair of the BestPractices Steam Steering Committee. Ms. Debbie Bloom, Senior Consultant for Nalco Company, continues as Vice-Chair. Mr. Doug Riley, Director of Global Energy of Millennium Chemicals, serves as the Executive At-Large. These individuals participate on the BestPractices Steam Steering Committee: Bob Bessette President, Council of......

Words: 29283 - Pages: 118

Premium Essay

Doctor

...1/ ENERGY BANDS IN SOLIDS In this chapter we begin with a review of the basic atomic properties of matter leading to discrete electronic energy levels in atoms. We find that these energy levels are spread into energy bands in a crystal. This band structure allows us to distinguish between an insulator, a semiconductor, and a metal. 1-1 CHARGED PARTICLES The charge, or quantity, of negative electricity and the mass of the electron have been found to be 1.60 X 10- 19 C (coulomb) and 9.11 X 10- 31 kg, respectively. The values of many important physical constants are given in Appendix A, and a list of conversion factors and prefixes is given in Appendix B. Some idea of the number of electrons per second that represents current of the usual order of magnitude is readily possible. F'or example, since the charge per electron is 1.60 X 10- 19 C, the number of electrons per coulomb is the reciprocal of this nutnber, or approximately, 6 X 10 18 Further, since a current of 1 A (ampere) is the flow of 1 Cis, then a current of only 1 pA (1 picoampere, or 10- 12 A) represents the motion of approximately 6 million electrons per second. Yet a current of 1 pA is so small that considerable difficulty is experienced in attempting to measure it. The charge of a positive ion is an integral multiple of the charge of the electron, although it is of opposite sign. For the case of singly ionized particles, the charge is equal to that of the electron. For the case of doubly ionized particles...

Words: 63477 - Pages: 254

Premium Essay

Electrical Installation Standards

...MINISTRY OF POWER AND MINERAL RESOURCES OF THE REPUBLIC OF KAZAKHSTAN APPROVED by Prikaz No 189 of the Minister of Power and Mineral Resources of the Republic of Kazakhstan, as of August 26, 2004.) REGULATIONS ON ELECTRICAL INSTALLATIONS OF THE REPUBLIC OF KAZAKHSTAN (PUE) Astana, 2003 TABLE OF CONTENTS SECTION 1: GENERAL REGULATIONS 10 CHAPTER 1.1: GENERAL 10 SCOPE, TERMS AND DEFINITIONS 10 GENERAL REGULATIONS FOR INSTALLATION OF ELECTRICAL EQUIPMENT 11 CONNECTION OF ELECTRICAL INSTALLATIONS TO THE POWER STATIONS 13 COMMISSIONING OF ELECTRICAL INSTALLATIONS 14 CHAPTER 1.2 POWER SUPPLY AND POWER SYSTEMS 14 SCOPE, DEFINITIONS 14 GENERAL REQUIREMENTS 14 CATEGORIES OF POWER CONSUMING DEVICES AND RELIABILITY OF POWER SUPPLY 15 VOLTAGE LEVELS AND CONTROLS, REACTIVE POWER COMPENSATION 16 CHAPTER 1.3 SELECTION OF CONDUCTORS: HEATING, CURRENT DENSITY AND CORONA DISCHARGE CONDITIONS 16 SCOPE 16 SELECTION OF CROSS-SECTION OF CONDUCTORS: HEATING 17 MAXUIMUM CONTINUOUS CURRENTS FOR WIRES, CORDS AND CABLES IN RUBBER OR PLASTIC INSULATION 18 MAXIMUM CONTINUOUS CURRENTS FOR CABLES IN IMPREGNATED PAPER INSULATION 22 MAXIMUM CONTINUOUS CURRENTS FOR BARE......

Words: 177034 - Pages: 709

Free Essay

Global Warming

...Physical Chemistry Understanding our Chemical World Physical Chemistry Understanding our Chemical World Paul Monk Manchester Metropolitan University, UK Copyright  2004 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Telephone (+44) 1243 779777 Email (for orders and customer service enquiries): cs-books@wiley.co.uk Visit our Home Page on www.wileyeurope.com or www.wiley.com All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of the Publisher. Requests to the Publisher should be addressed to the Permissions Department, John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England, or emailed to permreq@wiley.co.uk, or faxed to (+44) 1243 770620. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the Publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Other......

Words: 233668 - Pages: 935

Free Essay

Maglev

...*3963103* [3963] – 103 T.E. (Petroleum) (Semester – I) Examination, 2011 DRILLING & PRODUCTION OPERATIONS (2003 Course) Time : 3 Hours Max. Marks : 100 Instructions : 1) Question Nos. 1 and 5 are compulsory. Out of the remaining attempt 2 questions from Section I and 2 questions from Section II. 2) Answers to the two Sections should be written in separate books. 3) Neat diagrams must be drawn wherever necessary. 4) Black figures to the right indicate full marks. 5) Use of Logarithmic Tables, Slide Rule, Mollier Charts, Electronic Pocket Calculator and Steam Tables is allowed. 6) Assume suitable data, if necessary. SECTION – I 1. What are different systems on a drilling rig ? Explain any one in detail with suitable diagramme. 18 2. a) Calculate Bottom hole pressure if well depth is 2500 m and mud weight is 1.2 gm/cc. b) Calculate mud weight if mud gradient is 0.87 psi/ft. ′ c) Calculate volume bbl/meter for drill pipe O.D. = 5′ inch and I.D. = 4.276 inch. 2 2 2 10 8 8 16 d) Draw circulation system on a drilling rig. 3. a) Discuss IADC classification of a bit in details. b) Discuss different factors affecting rate of penetration in details. 4. Write short note on : i) Coring ii) Fishing tools iii) BOP iv) Directional well P.T.O. [3963] – 103 -2- *3963103* SECTION – II 5. a) Discuss different types of casings and function of the casings in brief. b) Discuss different types of well completion techniques. 6. a) Discuss primary cementation process......

Words: 172166 - Pages: 689

Free Essay

Bad Bug Book

...Introduction  Food safety is a complex issue that has an impact on all segments of society, from the general public to government, industry, and academia. The second edition of the Bad Bug Book, published by the Center for Food Safety and Applied Nutrition, of the Food and Drug Administration (FDA), U.S. Department of Health and Human Services, provides current information about the major known agents that cause foodborne illness. The information provided in this handbook is abbreviated and general in nature, and is intended for practical use. It is not intended to be a comprehensive scientific or clinical reference. Under the laws administered by FDA, a food is adulterated if it contains (1) a poisonous or otherwise harmful substance that is not an inherent natural constituent of the food itself, in an amount that poses a reasonable possibility of injury to health, or (2) a substance that is an inherent natural constituent of the food itself; is not the result of environmental, agricultural, industrial, or other contamination; and is present in an amount that ordinarily renders the food injurious to health. The first includes, for example, a toxin produced by a fungus that has contaminated a food, or a pathogenic bacterium or virus, if the amount present in the food may be injurious to health. An example of the second is the tetrodotoxin that occurs naturally in some organs of some types of pufferfish and that ordinarily will make the fish injurious to health. In either......

Words: 91823 - Pages: 368

Premium Essay

Microbiology Made Ridiculously Simple

...antibiotics. The mnemonics and cartoons in this book do not intend disrespect for any particular patient population or racial or ethnic group but are solely presented as memory devices to assist in the learning of a complex and important medical subject. We welcome suggestions for future editions. 1) Write in a conversational style for rapid assimilation. 2) Include numerous figures serving as "visual memory tools" and summary charts at the end of each chapter. These can be used for "cram sessions" after the concepts have been studied in the text. 3) Concentrate more on clinical and infectious disease issues that are both interesting and vital to the actual practice of medicine. MARK GLADWIN, MD BILL TRATTLER, MD D CONTENTS Preface v PART 1 1 2 3 BACTERIAL TAXONOMY CELL STRUCTURES, VIRULENCE FACTORS, and TOXINS...

Words: 117402 - Pages: 470

Free Essay

La Singularidad

...NOTE: This PDF document has a handy set of “bookmarks” for it, which are accessible by pressing the Bookmarks tab on the left side of this window. ***************************************************** We are the last. The last generation to be unaugmented. The last generation to be intellectually alone. The last generation to be limited by our bodies. We are the first. The first generation to be augmented. The first generation to be intellectually together. The first generation to be limited only by our imaginations. We stand both before and after, balancing on the razor edge of the Event Horizon of the Singularity. That this sublime juxtapositional tautology has gone unnoticed until now is itself remarkable. We're so exquisitely privileged to be living in this time, to be born right on the precipice of the greatest paradigm shift in human history, the only thing that approaches the importance of that reality is finding like minds that realize the same, and being able to make some connection with them. If these books have influenced you the same way that they have us, we invite your contact at the email addresses listed below. Enjoy, Michael Beight, piman_314@yahoo.com Steven Reddell, cronyx@gmail.com Here are some new links that we’ve found interesting: KurzweilAI.net News articles, essays, and discussion on the latest topics in technology and accelerating intelligence. SingInst.org The Singularity Institute for Artificial Intelligence: think tank devoted to......

Words: 237133 - Pages: 949

Free Essay

Reflection Paper About Precious

...This page intentionally left blank Physical Constants Quantity Electron charge Electron mass Permittivity of free space Permeability of free space Velocity of light Value e = (1.602 177 33 ± 0.000 000 46) × 10−19 C m = (9.109 389 7 ± 0.000 005 4) × 10−31 kg �0 = 8.854 187 817 × 10−12 F/m µ0 = 4π10−7 H/m c = 2.997 924 58 × 108 m/s Dielectric Constant (�r� ) and Loss Tangent (� �� /� � ) Material Air Alcohol, ethyl Aluminum oxide Amber Bakelite Barium titanate Carbon dioxide Ferrite (NiZn) Germanium Glass Ice Mica Neoprene Nylon Paper Plexiglas Polyethylene Polypropylene Polystyrene Porcelain (dry process) Pyranol Pyrex glass Quartz (fused) Rubber Silica or SiO2 (fused) Silicon Snow Sodium chloride Soil (dry) Steatite Styrofoam Teflon Titanium dioxide Water (distilled) Water (sea) Water (dehydrated) Wood (dry) � r �� / � 1.0005 25 8.8 2.7 4.74 1200 1.001 12.4 16 4–7 4.2 5.4 6.6 3.5 3 3.45 2.26 2.25 2.56 6 4.4 4 3.8 2.5–3 3.8 11.8 3.3 5.9 2.8 5.8 1.03 2.1 100 80 1 1.5–4 0.1 0.000 6 0.002 0.022 0.013 0.000 25 0.002 0.05 0.000 6 0.011 0.02 0.008 0.03 0.000 2 0.000 3 0.000 05 0.014 0.000 5 0.000 6 0.000 75 0.002 0.000 75 0.5 0.000 1 0.05 0.003 0.000 1 0.000 3 0.001 5 0.04 4 0 0.01 Conductivity (� ) Material Silver Copper Gold Aluminum Tungsten Zinc Brass Nickel Iron Phosphor bronze Solder Carbon steel German silver Manganin Constantan Germanium Stainless steel , S/m 6.17 × 107 4.10 × 107 3.82 × 107 1.82 × 107 1.67 × 107 1.5 × 107 1.45 × 107 1.03...

Words: 177667 - Pages: 711

Free Essay

Deeepwater

...Western Michigan University ScholarWorks at WMU Dissertations Graduate College 8-1-2012 Deepwater, Deep Ties, Deep Trouble: A StateCorporate Environmental Crime Analysis of the 2010 Gulf of Mexico Oil Spill Elizabeth A. Bradshaw Western Michigan University, brads2ea@cmich.edu Follow this and additional works at: http://scholarworks.wmich.edu/dissertations Recommended Citation Bradshaw, Elizabeth A., "Deepwater, Deep Ties, Deep Trouble: A State-Corporate Environmental Crime Analysis of the 2010 Gulf of Mexico Oil Spill" (2012). Dissertations. Paper 53. This Dissertation-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Dissertations by an authorized administrator of ScholarWorks at WMU. For more information, please contact maira.bundza@wmich.edu. DEEPWATER, DEEP TIES, DEEP TROUBLE: A STATE-CORPORATE ENVIRONMENTAL CRIME ANALYSIS OF THE 2010 GULF OF MEXICO OIL SPILL by Elizabeth A. Bradshaw A Dissertation Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements for the Degree of Doctor of Philosophy Department of Sociology Advisor: Ronald C. Kramer, Ph.D. Western Michigan University Kalamazoo, Michigan August 2012 THE GRADUATE COLLEGE WESTERN MICHIGAN UNIVERSITY KALAMAZOO, MICHIGAN June 29, 2012 Date WE HEREBY APPROVE THE DISSERTATION SUBMITTED BY Elizabeth A. Bradshaw ENTITLED Deepwater, Deep Ties, Deep Trouble: A State-Corporate......

Words: 81631 - Pages: 327

Free Essay

Fsfdfdfd

...Oracle VM VirtualBox R User Manual Version 5.0.0 c 2004-2015 Oracle Corporation http://www.virtualbox.org Contents 1 First steps 1.1 Why is virtualization useful? . . . . . . . . . . . . . . . 1.2 Some terminology . . . . . . . . . . . . . . . . . . . . . 1.3 Features overview . . . . . . . . . . . . . . . . . . . . . 1.4 Supported host operating systems . . . . . . . . . . . . 1.5 Installing VirtualBox and extension packs . . . . . . . . 1.6 Starting VirtualBox . . . . . . . . . . . . . . . . . . . . 1.7 Creating your first virtual machine . . . . . . . . . . . 1.8 Running your virtual machine . . . . . . . . . . . . . . 1.8.1 Starting a new VM for the first time . . . . . . 1.8.2 Capturing and releasing keyboard and mouse 1.8.3 Typing special characters . . . . . . . . . . . . 1.8.4 Changing removable media . . . . . . . . . . . 1.8.5 Resizing the machine’s window . . . . . . . . 1.8.6 Saving the state of the machine . . . . . . . . 1.9 Using VM groups . . . . . . . . . . . . . . . . . . . . . 1.10 Snapshots . . . . . . . . . . . . . . . . . . . . . . . . . 1.10.1 Taking, restoring and deleting snapshots . . . 1.10.2 Snapshot contents . . . . . . . . . . . . . . . . 1.11 Virtual machine configuration . . . . . . . . . . . . . . 1.12 Removing virtual machines . . . . . . . . . . . . . . . . 1.13 Cloning virtual machines . . . . . . . . . . . . . . . . . 1.14 Importing and exporting virtual machines . . . . . . . 1.15 Global Settings . . . . . . . . . . . . . . . . . . . . . ....

Words: 143714 - Pages: 575

Premium Essay

Innovator Dillema

...College All rights reserved The Library of Congress has catalogued the hardcover edition of this title as follows: Christensen, Clayton M. The innovator’s dilemma : when new technologies cause great firms to fail / Clayton M. Christensen. p. cm. — (The management of innovation and change series) Includes index. ISBN 0-87584-585-1 (alk. paper) 1. Creative ability in business. 2. Industrial management. 3. Customer services. 4. Success in business. I. Title. II. Series. HD53.C49 1997 658—DC20 96-10894 CIP ISBN 0-87584-585-1 (Microsoft Reader edition) 3 Contents In Gratitude Introduction PART ONE: WHY GREAT COMPANIES CAN FAIL 1 How Can Great Firms Fail? Insights from the Hard Disk Drive Industry 2 Value Networks and the Impetus to Innovate 3 Disruptive Technological Change in the Mechanical Excavator Industry 4 What Goes Up, Can’t Go Down PART TWO: MANAGING DISRUPTIVE TECHNOLOGICAL CHANGE 5 Give Responsibility for Disruptive Technologies to Organizations Whose Customers Need Them 6 Match the Size of the Organization to the Size of the Market 7 Discovering New and Emerging Markets 8 How to Appraise Your Organization’s Capabilities and Disabilities 9 Performance Provided, Market Demand, and the Product Life Cycle 10 Managing Disruptive Technological Change: A Case Study 11 The Dilemmas of Innovation: A Summary The Innovator’s Dilemma Book Group Guide About the Author 4 In Gratitude Although this book lists only one author, in......

Words: 82673 - Pages: 331

Premium Essay

Future of Technology

...Negotiation Pocket World in Figures THE FUTURE OF TECHNOLOGY THE ECONOMIST IN ASSOCIATION WITH PROFILE BOOKS LTD Published by Profile Books Ltd 3a Exmouth House, Pine Street, London ec1r 0jh Copyright © The Economist Newspaper Ltd 2005 All rights reserved. Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording or otherwise), without the prior written permission of both the copyright owner and the publisher of this book. The greatest care has been taken in compiling this book. However, no responsibility can be accepted by the publishers or compilers for the accuracy of the information presented. Where opinion is expressed it is that of the author and does not necessarily coincide with the editorial views of The Economist Newspaper. Typeset in EcoType by MacGuru info@macguru.org.uk Printed and bound in Great Britain by Creative Print and Design (Wales), Ebbw Vale A CIP catalogue record for this book is available from the British Library ISBN 1 86197 971 1 Contents The authors Foreword Part 1 Information technology grows up 1 Coming of age 2...

Words: 128899 - Pages: 516

Premium Essay

Asdf

...permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher. ISBN: 978-0-07-177863-3 MHID: 0-07-177863-2 The material in this eBook also appears in the print version of this title: ISBN: 978-0-07177862-6, MHID: 0-07-177862-4. All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark. Where such designations appear in this book, they have been printed with initial caps. McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. To contact a representative please e-mail us at bulksales@mcgraw-hill.com. TERMS OF USE This is a copyrighted work and The McGraw-Hill Companies, Inc. (“McGraw-Hill”) and its licensors reserve all rights in and to the work. Use of this work is subject to these terms. Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you may not decompile, disassemble, reverse engineer, reproduce, modify, create derivative works based upon, transmit, distribute, disseminate, sell, publish or sublicense the work or any part of it......

Words: 87486 - Pages: 350

Premium Essay

Case Study Handbook

...1/22/07 3:37 PM Page i RP OS T ElletFM.qxp THE DO N OT C OP YO CASE STUDY HANDBOOK 1/22/07 3:37 PM Page ii DO N OT C OP YO RP OS T ElletFM.qxp 1/22/07 3:37 PM Page iii RP OS T ElletFM.qxp YO THE OP CASE STUDY HANDBOOK How to Read, Discuss, and OT C Write Persuasively About Cases DO N William Ellet Harvard Business School Press Boston, Massachusetts 1/22/07 3:37 PM Page iv RP OS T ElletFM.qxp Copyright 2007 William Ellet YO All rights reserved Printed in the United States of America 11 10 09 08 07 5 4 3 2 1 OP No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form, or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior permission of the publisher. Requests for permission should be directed to permissions@hbsp.harvard.edu, or mailed to Permissions, Harvard Business School Publishing, 60 Harvard Way, Boston, Massachusetts 02163. The copyright on each case in this book unless otherwise noted is held by the President and Fellows of Harvard College and they are published herein by express permission. Permission requests to use individual Harvard copyrighted cases should be directed to permissions@hbsp.harvard.edu, or mailed to the Permissions Editor, Harvard Business School Publishing, 60 Harvard Way, Boston, MA 02163. OT C Case material of the Harvard Graduate School of Business Administration is made possible by......

Words: 99835 - Pages: 400