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(SAM) Alloy Parts Using X-Ray CT
Research Article ISSN 2639-9466 Nanotechnology & Applications Porosity Determination and Characterization of Binder Jet Printed Structural Amorphous Metal (SAM) Alloy Parts Using X-Ray CT Amamchukwu B. Ilogebe1*, Benedict Uzochukwu2, and Amy M. Elliot3 1North Carolina A&T State University, US. *Correspondence: Amamchukwu B. Ilogebe, North Carolina A&T State University, 2Virginia State University, US. US. 3Oak Ridge National Laboratory, US. Received: 04 November 2019; Accepted: 29 November 2019 Citation: Amamchukwu B. Ilogebe, Benedict Uzochukwu, Amy M. Elliot. Porosity Determination and Characterization of Binder Jet Printed Structural Amorphous Metal (SAM) Alloy Parts Using X-Ray CT. Nano Tech Appl. 2019; 2(1): 1-6. ABSTRACT The advent of Binder jet additive manufacturing continued to a revelation in the manufacture of intricate metal parts. This technology has been utilized in medical, aerospace and automotive industries, not much has been reported in the printing of parts from amorphous metal powders, which have found numerous applications in engineering because of their special properties. In this research, special emphasis was placed on two different manufacturing methods for structural amorphous metal alloy (SAM alloy); Die compaction and Binder jet printing. Samples of SAM alloy was created from these two-manufacturing methods and were subsequently, sintered, analyzed and compared. Previous studies show that as much as up to 50% porosity could be recorded in binder jet printing [1,2]. In this regard, different techniques were used to determine the percentage porosity from both manufacturing methods. The Archimedes method was used to determine the density and percentage porosity of the parts from the two methods. Similarly, percentage porosity was also determined using different tools in computed tomography (CT) analysis. -
Combat Helmets and Blast Traumatic Brain Injury
Review Articles Combat Helmets and Blast Traumatic Brain Injury Duncan Wallace, FRANZCP and Stephen Rayner, DPsych (Clinical) Abstract: Background: The conflicts in Iraq and Afghanistan and the prominence of traumatic brain injury (TBI), mostly from improvised explosive devices, have focused attention on the effectiveness of combat helmets. Purpose: This paper examines the importance of TBI, the role and history of the development of combat helmets, current helmet designs and effectiveness, helmet design methodology, helmet sensors, future research and recommendations. Method: A literature review was conducted using search terms – combat helmets, traumatic brain injury, concussion, Iraq, Afghanistan and helmet sensors, searching PubMed, MEDLINE, ProQuest and Google Scholar. Conclusions: At present, no existing helmet is able to fully protect against all threats faced on the battlefield. The prominence of traumatic brain injury from improvised explosive devices in the current conflicts in Iraq and Afghanistan has highlighted the limitations in knowledge about blast and how to provide protection from it. As a result, considerable research is currently occurring in how to protect the head from blast over-pressure. Helmet sensors may provide valuable data. Some new combat helmets may be able to protect against rifle rounds, but may result in injuries occurring behind body armour. Optimal combat helmet design requires a balance between the need for protection from trauma and the comfort and practicality of the helmet for the user to ensure the best outcomes. Keywords: combat helmets, traumatic brain injury, concussion, Iraq, Afghanistan. No conflicts of interest were identified by the authors. Introduction Role and history of combat helmets Recent adverse media attention about combat The primary role of the combat helmet is to protect helmets used in Afghanistan by United States the soldier’s head against injury. -
Ballistic Helmets – Their Design, Materials, and Performance Against Traumatic Brain Injury
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln US Army Research U.S. Department of Defense 2013 Ballistic helmets – Their design, materials, and performance against traumatic brain injury S.G. Kulkarni Texas A&M University, [email protected] X.-L. Gao University of Texas at Dallas, [email protected] S.E. Horner U.S. Army, Fort Belvoir J.Q. Zheng U.S. Army, Fort Belvoir N.V. David Universiti Teknologi MARA Follow this and additional works at: https://digitalcommons.unl.edu/usarmyresearch Kulkarni, S.G.; Gao, X.-L.; Horner, S.E.; Zheng, J.Q.; and David, N.V., "Ballistic helmets – Their design, materials, and performance against traumatic brain injury" (2013). US Army Research. 201. https://digitalcommons.unl.edu/usarmyresearch/201 This Article is brought to you for free and open access by the U.S. Department of Defense at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in US Army Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Composite Structures 101 (2013) 313–331 Contents lists available at SciVerse ScienceDirect Composite Structures journal homepage: www.elsevier.com/locate/compstruct Review Ballistic helmets – Their design, materials, and performance against traumatic brain injury ⇑ S.G. Kulkarni a, X.-L. Gao b, , S.E. Horner c, J.Q. Zheng c, N.V. David d a Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, United States b Department of Mechanical Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080-3021, United States c Program Executive Office – SOLDIER, U.S. -
MILITARY INTELLIGENCE PB 34-09-2 Volume 35 Number 2 April - June 2009
MIPB April - June 2009 PB 34-O9-2 Operations in OEF Afghanistan FROM THE EDITOR In this issue, three articles offer perspectives on operations in Afghanistan. Captain Nenchek dis- cusses the philosophy of the evolving insurgent “syndicates,” who are working together to resist the changes and ideas the Coalition Forces bring to Afghanistan. Captain Beall relates his experiences in employing Human Intelligence Collection Teams at the company level in both Iraq and Afghanistan. Lieutenant Colonel Lawson provides a look into the balancing act U.S. Army chaplains as non-com- batants in Afghanistan are involved in with regards to Information Operations. Colonel Reyes discusses his experiences as the MNF-I C2 CIOC Chief, detailing the problems and solutions to streamlining the intelligence effort. First Lieutenant Winwood relates her experiences in integrating intelligence support into psychological operations. From a doctrinal standpoint, Lieutenant Colonels McDonough and Conway review the evolution of priority intelligence requirements from a combined operations/intelligence view. Mr. Jack Kem dis- cusses the constructs of assessment during operations–measures of effectiveness and measures of per- formance, common discussion threads in several articles in this issue. George Van Otten sheds light on a little known issue on our southern border, that of the illegal im- migration and smuggling activities which use the Tohono O’odham Reservation as a corridor and offers some solutions for combined agency involvement and training to stem the flow. Included in this issue is nomination information for the CSM Doug Russell Award as well as a biogra- phy of the 2009 winner. Our website is at https://icon.army.mil/ If your unit or agency would like to receive MIPB at no cost, please email [email protected] and include a physical address and quantity desired or call the Editor at 520.5358.0956/DSN 879.0956. -
Process, Structure, Property and Applications of Metallic Glasses
AIMS Materials Science, 3(3): 1022-1053. DOI: 10.3934/matersci.2016.3.1022 Received: 15 March 2016 Accepted: 07 July 2016 Published: 26 July 2016 http://www.aimspress.com/journal/Materials Short review Process, structure, property and applications of metallic glasses Bindusri Nair and B. Geetha Priyadarshini * Nanotech Research Innovation and Incubation Centre, PSG Institute of Advanced Studies, Coimbatore, Tamil Nadu, India-641004 * Correspondence: Email: [email protected]. Abstract: Metallic glasses (MGs) are gaining immense technological significance due to their unique structure-property relationship with renewed interest in diverse field of applications including biomedical implants, commercial products, machinery parts, and micro-electro-mechanical systems (MEMS). Various processing routes have been adopted to fabricate MGs with short-range ordering which is believed to be the genesis of unique structure. Understanding the structure of these unique materials is a long-standing unsolved mystery. Unlike crystalline counterpart, the outstanding properties of metallic glasses owing to the absence of grain boundaries is reported to exhibit high hardness, excellent strength, high elastic strain, and anti-corrosion properties. The combination of these remarkable properties would significantly contribute to improvement of performance and reliability of these materials when incorporated as bio-implants. The nucleation and growth of metallic glasses is driven by thermodynamics and kinetics in non-equilibrium conditions. This comprehensive review article discusses the various attributes of metallic glasses with an aim to understand the fundamentals of relationship process-structure-property existing in such unique class of material. Keywords: metallic glasses; glass transition; amorphous; mechanical properties 1. Introduction Metallic Glasses (MG) are a class of materials which has caught the eye of many researchers since Klement et al’s [1] first work on Au-Si alloys in early 1960’s. -
Mechanical Behavior of Amorphous Alloys
Acta Materialia 55 (2007) 4067–4109 www.elsevier.com/locate/actamat Overview No. 144 Mechanical behavior of amorphous alloys Christopher A. Schuh a,*, Todd C. Hufnagel b, Upadrasta Ramamurty c a Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, M.I.T., Cambridge, MA 02139, USA b Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA c Department of Materials Engineering, Indian Institute of Science, Bangalore-560 012, India Received 14 August 2006; received in revised form 29 January 2007; accepted 31 January 2007 Available online 19 April 2007 Abstract The mechanical properties of amorphous alloys have proven both scientifically unique and of potential practical interest, although the underlying deformation physics of these materials remain less firmly established as compared with crystalline alloys. In this article, we review recent advances in understanding the mechanical behavior of metallic glasses, with particular emphasis on the deformation and fracture mechanisms. Atomistic as well as continuum modeling and experimental work on elasticity, plastic flow and localization, frac- ture and fatigue are all discussed, and theoretical developments are connected, where possible, with macroscopic experimental responses. The role of glass structure on mechanical properties, and conversely, the effect of deformation upon glass structure, are also described. The mechanical properties of metallic glass-derivative materials – including in situ and ex situ composites, foams and nanocrystal- reinforced glasses – are reviewed as well. Finally, we identify a number of important unresolved issues for the field. Ó 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Metallic glass; Amorphous metal; Mechanical properties 1. -
An Annotated Bibliography of MANPRINT-Related Assessments and Evaluations Conducted by the U.S
An Annotated Bibliography of MANPRINT-Related Assessments and Evaluations Conducted by the U.S. Army, 2nd Edition: 1953 to 2009 Volume III – Test and Evaluation Reports by Sam E. Middlebrooks, Ph.D. ARL-SR-190 February 2010 Approved for public release; distribution is unlimited. NOTICES Disclaimers The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. Citation of manufacturer’s or trade names does not constitute an official endorsement or approval of the use thereof. Destroy this report when it is no longer needed. Do not return it to the originator. Army Research Laboratory Aberdeen Proving Ground, MD 21005-5425 ARL-SR-190 February 2010 An Annotated Bibliography of MANPRINT-Related Assessments and Evaluations Conducted by the U.S. Army, 2nd Edition: 1953 to 2009 Volume III –Test and Evaluation Reports Sam E. Middlebrooks, Ph.D. Human Research and Engineering Directorate, ARL Approved for public release; distribution is unlimited. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. -
The R3-Carbon Allotrope
The R3-carbon allotrope: a pathway towards glassy carbon under high SUBJECT AREAS: MECHANICAL pressure PROPERTIES ELECTRONIC MATERIALS Xue Jiang1,2, Cecilia A˚ rhammar3, Peng Liu1, Jijun Zhao2 & Rajeev Ahuja1,4 STRUCTURE OF SOLIDS AND LIQUIDS 1Department of Materials and Engineering, Royal Institute of Technology, 10044 Stockholm, Sweden, 2Key Laboratory of Materials ELECTRONIC STRUCTURE Modification by Laser, Ion and Electron Beams Dalian University of Technology, Ministry of Education, Dalian 116024, China, 3Sandvik Coromant, Lerkrogsv. 13, S-126 80 Stockholm, Sweden, 4Department of Physics and Astronomy, Box 516, Uppsala University, 75120, Uppsala, Sweden. Received 8 November 2012 Pressure-induced bond type switching and phase transformation in glassy carbon (GC) has been simulated Accepted by means of Density Functional Theory (DFT) calculations and the Stochastic Quenching method (SQ) in a 25 April 2013 wide range of pressures (0–79 GPa). Under pressure, the GC experiences a hardening transition from sp- and sp2-type to sp3-type bonding, in agreement with previous experimental results. Moreover, a new Published crystalline carbon allotrope possessing R3 symmetry (R3-carbon) is predicted using the stochastic SQ 23 May 2013 method. The results indicate that R3-carbon can be regarded as an allotrope similar to that of amorphous GC. A very small difference in the heat of formation and the coherence of the radial and angular distribution functions of GC and the R3-carbon structure imply that small perturbations to this crystalline carbon Correspondence and allotrope may provide another possible amorphization pathway of carbon besides that of quenching the liquid melt or gas by ultra-fast cooling. requests for materials should be addressed to J.Z. -
Atomistic Modelling of CVD Synthesis of Carbon Nanotubes and Graphene Cite This: Nanoscale, 2013, 5, 6662 James A
Nanoscale View Article Online FEATURE ARTICLE View Journal | View Issue Atomistic modelling of CVD synthesis of carbon nanotubes and graphene Cite this: Nanoscale, 2013, 5, 6662 James A. Elliott,*a Yasushi Shibuta,b Hakim Amara,c Christophe Bicharad and Erik C. Neytse We discuss the synthesis of carbon nanotubes (CNTs) and graphene by catalytic chemical vapour deposition (CCVD) and plasma-enhanced CVD (PECVD), summarising the state-of-the-art understanding of mechanisms controlling their growth rate, chiral angle, number of layers (walls), diameter, length and quality (defects), before presenting a new model for 2D nucleation of a graphene sheet from amorphous carbon on a nickel surface. Although many groups have modelled this process using a variety of techniques, we ask whether there are any complementary ideas emerging from the different proposed growth mechanisms, and whether different modelling techniques can give the same answers for a given mechanism. Subsequently, by comparing the results of tight-binding, semi-empirical fi Creative Commons Attribution 3.0 Unported Licence. molecular orbital theory and reactive bond order force eld calculations, we demonstrate that graphene on crystalline Ni(111) is thermodynamically stable with respect to the corresponding amorphous metal and carbon structures. Finally, we show in principle how a complementary heterogeneous nucleation Received 17th April 2013 step may play a key role in the transformation from amorphous carbon to graphene on the metal Accepted 5th June 2013 surface. We conclude that achieving the conditions under which this complementary crystallisation DOI: 10.1039/c3nr01925j process can occur may be a promising method to gain better control over the growth processes of both www.rsc.org/nanoscale graphene from flat metal surfaces and CNTs from catalyst nanoparticles. -
Worldwide Equipment Guide
WORLDWIDE EQUIPMENT GUIDE TRADOC DCSINT Threat Support Directorate DISTRIBUTION RESTRICTION: Approved for public release; distribution unlimited. Worldwide Equipment Guide Sep 2001 TABLE OF CONTENTS Page Page Memorandum, 24 Sep 2001 ...................................... *i V-150................................................................. 2-12 Introduction ............................................................ *vii VTT-323 ......................................................... 2-12.1 Table: Units of Measure........................................... ix WZ 551........................................................... 2-12.2 Errata Notes................................................................ x YW 531A/531C/Type 63 Vehicle Series........... 2-13 Supplement Page Changes.................................... *xiii YW 531H/Type 85 Vehicle Series ................... 2-14 1. INFANTRY WEAPONS ................................... 1-1 Infantry Fighting Vehicles AMX-10P IFV................................................... 2-15 Small Arms BMD-1 Airborne Fighting Vehicle.................... 2-17 AK-74 5.45-mm Assault Rifle ............................. 1-3 BMD-3 Airborne Fighting Vehicle.................... 2-19 RPK-74 5.45-mm Light Machinegun................... 1-4 BMP-1 IFV..................................................... 2-20.1 AK-47 7.62-mm Assault Rifle .......................... 1-4.1 BMP-1P IFV...................................................... 2-21 Sniper Rifles..................................................... -
TOTAL Headborne System Solutions GROUND PRODUCT CATALOG
TOTAL Headborne System Solutions GROUND PRODUCT CATALOG www.gentexcorp.com/ground USA Coast Guardsmen fast-rope from an Air Force UH-60G Pave Hawk helicopter during a training exercise at Air Station Kodiak, Alaska, Feb. 22, 2019. Photo By: Coast Guard Chief Petty Officer Charly Hengen Gentex Corporation takes pride in our dedication to the mission of providing optimal protection and situational awareness to global defense forces, emergency responders, and industrial personnel operating IT’S GO TIME in high-performance environments. 2 For complete product details, go to gentexcorp.com/ground 3 OUR PROUD HISTORY OUR PEERLESS QUALITY Gentex has been at the forefront of innovation for over 125 years, from product development to Gentex Corporation ensures that our Quality Management Systems consistently provide products quality enhancement and performance. Our philosophy of continually reinvesting in our employees, to meet our customers’ requirements and enables process measurements to support continuous our customers, and our capabilities and technologies shows in the growth of our business and the improvements. We comply with an ISO 9001 certified Quality Management System that is supplemented game-changing innovations our people have created. with additional quality system requirements that meet the AS9100D standard, a standard that provides strict requirements established for the aviation, space, and defense industries. 4 For complete product details, go to gentexcorp.com/ground 5 ENGINEERED & TESTED MISSION CONFIGURABLE Whether it’s a helmet system, a respiratory protection system, leading-edge optics, or a communication headset, Gentex It’s all about Open Architecture. Our approach to product integration results in systems with components that work together Corporation takes the same all-in approach to product design and engineering. -
Laser Additive Manufacturing of Fe-Based Magnetic Amorphous Alloys
magnetochemistry Review Laser Additive Manufacturing of Fe-Based Magnetic Amorphous Alloys Merve G. Ozden * and Nicola A. Morley Department of Material Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK; n.a.morley@sheffield.ac.uk * Correspondence: mgozden1@sheffield.ac.uk Abstract: Fe-based amorphous materials offer new opportunities for magnetic sensors, actuators, and magnetostrictive transducers due to their high saturation magnetostriction (ls = 20–40 ppm) and low coercive field compared with polycrystalline Fe-based alloys, which have high magne- tostriction but large coercive fields and Co-based amorphous alloys with small magnetostriction (ls = −3 to −5 ppm). Additive layer manufacturing (ALM) offers a new fabrication technique for more complex net-shaping designs. This paper reviews the two different ALM techniques that have been used to fabricate Fe-based amorphous magnetic materials, including the structural and magnetic properties. Selective laser melting (SLM)—a powder-bed fusion technique—and laser- engineered net shaping (LENS)—a directed energy deposition method—have both been utilised to fabricate amorphous alloys, owing to their high availability and low cost within the literature. Two different scanning strategies have been introduced by using the SLM technique. The first strategy is a double-scanning strategy, which gives rise to maximum relative density of 96% and corresponding magnetic saturation of 1.22 T. It also improved the glassy phase content by an order of magnitude of 47%, as well as improving magnetic properties (decreasing coercivity to 1591.5 A/m and increasing magnetic permeability to around 100 at 100 Hz). The second is a novel scanning strategy, which Citation: Ozden, M.G.; Morley, N.A.