ASTM Committee Research Articles

Influence of activator ratios and concentration on the physio-mechanical and microstructural characteristics of the geopolymers derived from sandstone processing waste.

Natural stones have been utilized to meet various needs of human civilization since ancient times. The exploitation of any resource is associated with the production of redundant materials called wastes. Sandstone waste (SW) is one such waste obtained during the industrial processing of sandstones. Due to its siliceous composition, extensive yield, and disorganized dumping, noxious conditions related to land and human health are promoted. However, the lack of comprehensive engineering studies, mineralogical analysis, and design methodologies associated with the utilization of sandstone processing wastes restricted their applicability only to fillers or partial substitutes with pozzolans and traditional cement in meager volumes. In the past, limited efforts have been made to utilize SW as a construction entity, particularly for binding purposes. Thus, to enhance the scope of its utilization, a comprehensive investigation has been performed in this research to transform sandstone waste into a novel construction material by geopolymerization. Mix design tailoring and laboratory tests were implemented to understand the effects of sodium hydroxide concentration and sodium silicate to sodium hydroxide ratio on the dissolution and physio-mechanical characteristics of SW-based geopolymers. The activator-to-binder ratio was restricted to 0.4 to obtain pastes with sufficient workability without hindering the properties of the matrix. Besides, a high temperature-curing regime was selected based on SW's crystallographic and reactivity analysis. Subsequently, a total of 48 samples were prepared and tested at the curing age of 28 days. Detailed characterization of SW and SW-based geopolymer samples was performed using optical, X-ray, and infrared spectroscopies aided by electron imaging and thermogravimetric techniques. SW-based geopolymer samples showed compressive strengths in the range of 6-12 MPa, ~2 to 3 times higher than those obtained in previous experimentations. Phase analysis and microstructural examinations confirmed SW's participation in geopolymerization. Overall, it could be advocated that geopolymerization is an innovative approach for solving issues related to the disposal and re-utilization of SW, extending its possible application to the fields of cement mixes, wall tiles, mortars, and masonry as per the commendations of ASTM and ACI committee.

The characterization of wear-causing particles and silica sand in particular

Erodants and abradants are two types of wear-causing particles (WCP). Despite their effects on the severity and rate of wear, WCP are inadequately characterized in a surprising number of publications, especially those involving impingement erosion and three-body abrasion. That shortfall makes it difficult to correlate features of WCP with the details of worn surfaces, or to develop wear models that account for those features. It is argued that the documentation of WCP should go beyond simply reporting their composition and mean particle size. In late 1985, ASTM Committee G2 on Wear and Erosion established a task group on the characterization of WCP. At that time, image analysis was slower and less sophisticated than it is today. While that ASTM task group failed to produce a consensus standard, computerized particle characterization methods were developing in fields other than tribology, fields like geoscience, heavy sand mining, materials processing, and pharmaceuticals. A notable exception to this is ferrography, which is a widely-used diagnostic for lubricated tribosystems. In the context of dry wear, it is useful to identify which features of WCP would be beneficial to document, and to identify some techniques and scales of detail appropriate to particular tribosystems. Examples are presented here for the morphological and mechanical characterization of silica sand grains, as prompted by a triboanalysis of the abrasive and erosive wear of biomass pre-processing equipment. The authors propose a minimum level of documentation for WCP, one that can enrich tribosystem analysis both in laboratory tests and field studies.

Codes and standards for ceramic composite core materials for High Temperature Reactor applications

Fiber-reinforced ceramic matrix composites are attractive for high-temperature nuclear applications due to excellent thermal and mechanical properties as well as reasonable-to-outstanding radiation resistance. Over the past 20 years, the use of ceramic matrix composite applications expanded to many commercial non-nuclear industries as fabrication and application of the technologies mature.The ASME Boiler Pressure Vessel Code, under Section III Division 5, provides the design and construction rules for High Temperature Reactor components. It published the first rules for ceramic matrix composites to be used for reactor core components. The rules lay out the quality requirements together with the design and materials criteria for the use and application of silicon carbide- and carbon-based matrix material technologies. As with the established graphite rules, the ceramic composite material rules are structured in Subsection HH (from Section III), that addresses the criteria for class SN nonmetallic core components. The code rules rely heavily on the development and publication of standards for composite specification, classification, and testing of mechanical, thermal, and other properties. These test methods are developed in ASTM Committee C28 on Advanced Ceramics, with a current focus on ceramic composite tubes. This article describes the detail of the composites code, the design methodology and similarities to the graphite code, the guidance for the development of specifications for ceramic composites (for nuclear applications) including recent standard developments, and it mentions the next steps to support licensing aspects by validating the code with benchmarking data.

Measurement and Importance of Volatile Matter in Coals and Biofuels

Abstract Volatile matter values for solid fuels are used to assess their burning rates and, thus, provide a basis for the buying and selling of these fuels. The major factors that affect volatile matter yields are the type of fuel, moisture contents, and the heating rates used in the tests. This paper reports the results of experiments designed to improve the reliability and application of test methods for the determination of volatile matter in various solid fuels. The macro thermogravimetric analysis studies described herein include the rapid drying of analysis samples of coal and the effect on volatile matter yields, the heating of various chars at high temperatures to reach a state of constancy, the measuring of decomposition moisture, an “elusive” constituent in coal, and the cocombustion of coals and other solid fuels. The presence of residual moisture and decomposition moisture in the coal during the volatile matter tests increases the measured volatile matter yields even though the residual moisture has been factored out. The rates of heating solid fuels during volatile matter tests affect the volatile matter yields because of the presence of different types of moisture in the fuel that are released at different temperatures. The heating rates used in volatile matter tests affect the type of compounds released and the total volatile matter yields of coals and biofuels. The experiments reported in this paper were instrumental in the decision of ASTM Committee D05 on Coal and Coke to recently revise the classic volatile matter standard test method D3175 to change the temperature for drying sparking coals from 600°C to 107°C. The role volatile matter plays in the combustion of fuel blends is discussed in this article.

Setting standards in sensory analysis

Setting standards in sensory analysis

A review of ASTM D7979 for the analysis of per‐ and polyfluorinated alkyl substances in non‐potable water by co‐solvation with methanol and using liquid chromatography–tandem mass spectrometry

Per- and polyfluorinated alkyl substances are large class of man-made compounds known in the media as "forever chemicals". In 2015, ASTM International published ASTM D7979, for the analysis of per- and polyfluorinated alkyl substances in non-potable water samples. This method extracts the substances by co-solvation with methanol and measures targeted compounds using liquid chromatography-tandem mass spectrometry. ASTM D7979 is a performance-based method that analyzes 31 compounds plus 14 isotopically labeled surrogates. The minimum reporting limit is approximately 10ng/L with an analytical range of 10-200ng/L for most compounds. Expected recovery of surrogates and spiked matrices is 70-130%. Samples containing high suspended solids can be analyzed with minimal interferences and potential loss of analyte. The method is consistent with ASTM and EPA's sustainable development goals by using reduced volumes of sample, solvent, and minimizing hazardous solvents and sample preparation materials while maintaining data quality and detection limits that are suitable for the intended use. This paper covers the rationale, outlines some of the challenges associated with analysis of per- and polyfluorinated alkyl substances, and describes the steps taken by the ASTM Committee D19 task group to develop, optimize, and validate this method.

A GC × GC Tier [formula omitted] combustor operability prescreening method for sustainable aviation fuel candidates

Fuels derived from sustainable feedstocks have significant potential to reduce greenhouse gas emissions associated with aviation. These alternative aviation fuels need to meet comprehensive safety and compatibility requirements established by an ASTM committee to achieve approval. To date, only seven annexes that define the property and compositional requirements for alternative fuels have been approved due, in part, to the significant cost and time required for evaluation and approval. Here, a Tier α sustainable aviation prescreening tool has been developed to predict the acceptability of novel SAF candidates, with the minimal volume required. Two-dimensional gas chromatography was used to determine the composition and size distribution of 20 alternative fuels, and Monte Carlo sampling was subsequently performed with a hydrocarbon database to predict eight properties that are important for combustor operability. These predicted properties were compared to experimentally measured properties, and uncertainty quantification was performed to validate the Tier α prescreening tool. The result of this validation suggests that four out of eight property confidence intervals are valid. Untuned predictions for properties with lower property variance across a given hydrocarbon type and carbon number, such as density and flash point, perform better than properties with significant property variance, such as freeze point and viscosity. The Tier α evaluation is outside of the ASTM evaluation process; however, this tool can provide feedback on downstream approval issues and facilitate fuel producer chemical process modeling thereby de-risking technology development. Thus, Tier α provides an early, rapid, and cost-effective evaluation for SAF candidates that requires minimal material volumes.

Editorial

Abstract On behalf of ASTM International and the Geotechnical Testing Journal (GTJ), I’m writing to thank Dr. William (Bill) J. Likos for his outstanding service as a GTJ Co-Editor and to welcome Dr. Nazli Yesiller as she transitions into this role starting in January 2021. Bill is the Gary Wendt Professor of Civil and Environmental Engineering at the University of Wisconsin–Madison and chair of the department. His expertise is in the area of geotechnical engineering, with particular emphasis on unsaturated soil mechanics and expansive clay behavior. He published one of the first textbooks on unsaturated soil mechanics and authored numerous journal and conference papers. He is a two-time recipient of the American Society of Civil Engineers (ASCE) Norman Medal and was awarded the ASCE Walter L. Huber Civil Engineering Research Prize and the Arthur Casagrande Professional Development Award. Bill also received the Transportation Research Board K. B. Woods Award. Bill has been a member of ASTM and has served as Co-Editor of the GTJ since 2009. He is an active member of ASTM Committees D18 on Soil and Rock and A01 on Steel, Stainless Steel and Related Alloys, and is currently serving as chair of the ASTM Committee on Publications. In 2019, Bill received the Committee D18 C. A. Hogentogler Award. He guided the GTJ as a Co-Editor for 12 years and has been a tremendous part of the journal’s success. During that time, review turnaround times reduced drastically, paper count increased significantly, and the Journal Impact Factor more than doubled. We are grateful to Bill for his outstanding dedication and service to the journal. Thank you, Bill. Dr. Nazli Yesiller will begin her first term as a GTJ Co-Editor in January 2021. Nazli received BS and MS degrees in Civil Engineering from Bogazici University, Istanbul, in 1989 and 1991, respectively, and she received a PhD in Civil and Environmental Engineering from the University of Wisconsin–Madison in 1994. Nazli has been the director of the Global Waste Research Institute at California Polytechnic State University since 2010. Nazli has authored numerous journal papers, conference proceedings, reports, and magazine articles. Nazli has been very active in ASTM International, having joined Committee D35 in 1998 and Committee D18 in 2002. She is currently the 1st Vice Chair of Committee D18, Chair of Subcommittees D18.14 (Geotechnics of Sustainable Construction), and D18.98 (Hogentogler Award). She has been a Vice Chair of Committee D18 from 2018 to 2020, a member-at-large of the D18 Executive Committee from 2014 to 2018, and Chair of Subcommittee D18.04 (Hydrologic Properties and Hydraulic Barriers) from 2006 to 2016. She began serving on the Editorial Board of the GTJ in 2003 and chaired the GTJ awards committee between 2010 and 2020. She has authored/co-authored five ASTM standards. Nazli received a New Standard Development Award from Committee D35, four Richard S. Ladd Standards Development Awards from Committee D18, two Special Service Awards from Committee D18, and the 2007 Award for Outstanding Article on the Practice of Geotechnical Testing from the GTJ. I look forward to working with Nazli to continue to make the GTJ the premier journal that it is. Welcome, Nazli. Finally, I would like to thank the authors for choosing the GTJ for publication of your manuscripts and the ASTM International staff, our outstanding editorial board members, and the numerous peer reviewers for their time, effort, and service to the GTJ.

A review on the state-of-the-art of surface finishing processes and related ISO/ASTM standards for metal additive manufactured components

ABSTRACT The current state-of-the-art metal additive manufacturing (AM) process still cannot meet the high industry requirements in terms of surface roughness. In addition, there are limited ISO/ASTM standards on the post-processing of metal AM components. Considerable efforts have been made to close these current gaps and challenges for standardization. In this review, First, all the existing ISO/ASTM standards under the jurisdiction of ASTM Committee F42 on additive manufacturing technologies are briefly discussed. Second, two of the most promising additive manufacturing processes: powder bed fusion (PBF) and directed energy deposition (DED), as well as their common defects of AM components, are thoroughly reviewed. The build quality, surface finish characteristics, and dimensional integrity of the as-built AM components are still not satisfactory (i.e., Ra > 5 µm and Rz > 100 µm). Third, the review is focused on identifying potential solutions to surface-finish complex additive manufactured geometries and reduce the surface roughness to meet the industry requirements (i.e., Ra < 1 µm and Rz < 20 µm). Current state-of-the-art surface finishing techniques, their material removal mechanisms, process parameters, advantages, and limitations to post-process PBF components are discussed. The technical gaps and future perspectives in enhancing the surface quality of AM components are outlined.

The effect of aggregate type and gradation on fragmentation resistance performance: Testing and evaluation based on different standard test methods

Abstract Aggregates used in construction works must be sufficiently durable in that long-lasting performance. Aggregates are exposed to external loads and harsh environmental conditions in all processes from manufacturing to use in the field. These cause fragmentation, abrasion, polishing of aggregates. Aggregates in different origin show distinct characteristics based on their chemical formation and the physical features at that moment such as shape and size. To make the properties of aggregates clear, series of test are implemented. Fragmentation resistance (FR) test using Los-Angeles apparatus is one of test in the series used to identify the strength of aggregate. This test can be performed based on different standard test methods such as the standard by American Society for Testing and Materials, ASTM and European Committee for Standardization, CEN, which are focused on in the current study. However, these two standards differ from each other in a few aspects such as aggregate size and mass of aggregate and charges. Based on these fundamental differences, a question has arisen about the effect of the aggregate size on the FR based on different origin. Respectively, this study was established on this case by using related ASTM and CEN standard. To achieve the answer, different sources of aggregates including metallurgical slags were supplied and a series of tests were performed on them to identify their physical, mechanical and chemical properties. Thereinafter, FR tests were performed in five different grain size distributions ranging from 2.36 to 37.50 mm according to ASTM C131 and CEN 1097-2. The results showed that aggregates in different origin, as expected, exhibited different FR values. However, there exist significant differences between FR values of aggregates tested in different grain size although the materials are the same. Considering the grain size of aggregate being used in the related works, testing and evaluation of FR performance of aggregate will be more accurate and robust. Therefore, the authors recommended that following ASTM standard for testing FR due to the optional grading will give more precise vision about aggregate’s performance.

Update of the History of ASTM Committee D18 on Soil and Rock (2006–2015)

Abstract This update on the activities of the committee meetings of ASTM Committee D18 on Soil and Rock covers the years from 2006 through 2015. The purpose of the this update is to highlight the activities of the biannual meetings, winter and summer, of Committee D18, to list members’ awards, and to indicate those members who have deceased during this period. The paper was reviewed by Jeanne Asquith (3Rd Rock LLC, East Aurora, NY) and Ron Holsinger (retired).

Update of the History of ASTM Committee D18 on Soil and Rock (1996–2005)

Abstract This update on the activities of the committee meetings of ASTM Committee D18 on Soil and Rock covers the years 1996–2005. The purpose of this update is to highlight the activities of the biannual meetings, winter and summer, of Committee D18, to list members’ awards, and to indicate those members who have deceased during this period. This article was reviewed by Amy Germaine (Fugro) and Jan Wildman (retired).

Impact of an Inclined Work Surface on the Measured Slump of Concrete

Abstract ASTM C143/C143M-15a, Standard Test Method for Slump of Hydraulic-Cement Concrete, states that the slump test is to be conducted on a level work surface. However, the standard does not provide a method for determining if a work surface is level, a tolerance for levelness, or guidance on what to do in the event that a work surface is not level. More importantly, field technicians need to know at what angle(s) and slump(s), if any, an inclined work surface will significantly influence the measured slump. A study at Valparaiso University included 114 simultaneous measures of slump on a horizontal and separate inclined work surface. This study indicates that inclination angles greater than 6° will influence the outcome of a slump test for slumps of 5 to 7 in. (127 to 179 mm). There is no evidence of concrete “leaning over” for lower inclinations or slumps. At high angles and high slumps, the fluidity of the concrete negates any influence of the inclination. Consequently, it is recommended that ASTM Committee C09.60 on Fresh Concrete Testing add language to C143 requiring the slump test to be conducted on a work surface with an inclination less than 6°, which equates to a 1:9.5 gradient and 10.5 % slope, regardless of the slump of the concrete.

Bayesian Subset Selection Methods for Finding Engineering Design Values: an Application to Lumber Strength

The paper concerns a random property T of a manufactured product that must with high probability e.g. P* = 95% exceed a specified quantity ηa called the characteristic value (CV). However the product comes from any one of K different subpopulations that may represent such things as manufacturers, regions or countries; the distribution of T will generally differ from one subpopulation to another and so will the associated CV ηka, = 1,…,K. Moreover in applications such as the one we focus on in this paper where the subpopulations are species, the subpopulation of origin will, for both strategic or practical reasons, not be known. The problem confronted in this paper is the creation of a single CV for the population consisting of the union of all the subpopulations. A solution proposed long ago in the application concerning manufactured lumber that is addressed in this paper, selects a subset of the subpopulations using random samples of the T s, called the subset of controlling species CS, that includes the smallest of the {ηka} with high probability. The estimated CV for the entire population is then found by combining and treating as one, the samples for the subpopulations in CS. That method has been published in an ASTM standards document for the lumber industry to ensure the structural engineering strength of manufactured lumber. However this published method has been shown to have some unexpected and undesirable properties, leading to the search for an alternative and this paper. The paper presents and compares three subset selection methods. The simplest of the three methods is an extension of a classical nonparametric method for subset selection. The remaining two, which are more complex, are variations of nonparametric Bayesian methods. Each of the three is seen as a possible candidate for consideration by ASTM committees as a possible replacement for the ASTM method for lumber species depending on what criterion is ultimately used for its selection. But they may well apply in other contexts as well.

Who Decides Who Rides: Examining Amusement Ride Access Policies and Title III

Have you ever visited an amusement park and watched a park employee instruct a guest that he or she may not experience a ride because of a certain physical attribute? Have you ever wondered how these policies are created? A trio of Title III wrongful discrimination claims filed against amusement park owners in 2012 and 2013 illuminated the tension that exists between Title III ADA regulations, Access Board guidelines, state regulatory schemes for amusement rides, and individual rider access policies on amusement rides. Circumstances did not require the courts to analyze the creation, implementation, and regulation of amusement ride access policies, so the issue of whether these access policies violate Title III was not fully discussed. This article does just that. Manufacturers and owners of modern amusement rides adhere to practice standards that regulate the design, construction, testing, operation, and maintenance of amusement rides. These standards, created by ASTM Committee F-24, provide the framework for the creation and implementation of rider access policies on modern amusement rides. Evidence suggests that owners of amusement rides likely adhere to Title III’s selection criteria exceptions when they restrict access to individual guests based on manufacturer-created rider access policies created in accordance with ASTM standards. Despite arguments that rider access policies are over-reaching and duplicitous, owners and manufacturers strive for transparency and inclusivity, increasing potential rider access by working together to create new devices that increase experiences for disabled riders on the newest, most thrilling amusement rides.

Results of Interlaboratory Test Programs to Assess the Precision of Inclusion Ratings by Methods A, C, and D of ASTM E45

Abstract Over the years, ASTM Committee E4 on metallography has conducted interlaboratory test programs to evaluate the precision and bias associated with measurements of microstructure using proposed and existing test methods. ASTM decided in the late 1970s that all test methods that generated numerical data must have a precision and bias section defining the repeatability and reproducibility of the method. Defining bias associated with a test method is difficult unless there is an absolute known value for the quantity being measured and this is not possible when microstructural features are being measured. This paper shows the results for an interlaboratory test using Method A, “worst-field” ratings of inclusions in steels using the original Plates I and III of ASTM E45, using Method C, a worst-field rating using Plate II; and, using Method D, a quantitative approach where every field is rated using Plates I and III. The results from nine people who were reported to be qualified, regular users of the method revealed consistent problems of misclassification of inclusion types and a wide range of severity ratings for each specimen. The test results using an image analyzer will be compared to that of the manual raters.

Metrics for acoustical measurements in North America

The primary source of standards for acoustical measurements in buildings and community noise for North America is ASTM E33 on Building and Environmental Acoustics. This paper focuses on the ASTM E33 standards and the metrics generated. There are six major categories of standards, Sound Absorption, Speech Privacy, Sound Transmission, Application of Materials and Systems, Mechanical and Electrical Noise, and Community Noise. The most familiar metrics include NRC, STC, and IIC, but there is an alphabet soup of metrics including AC, AI, AOITC(θ), ANISPL, ATL, CNEL, FSTC, NIC, and OINIC. Many of these are variations of the basic measurements targeting a specific measurement environment. This paper focuses on the basic measurements and how the metrics are calculated and then gives a broad overview of the range of variations and specialized test methods available through ASTM Committee E33 standards.

Mobile Robot and Mobile Manipulator Research Towards ASTM Standards Development.

Performance standards for industrial mobile robots and mobile manipulators (robot arms onboard mobile robots) have only recently begun development. Low cost and standardized measurement techniques are needed to characterize system performance, compare different systems, and to determine if recalibration is required. This paper discusses work at the National Institute of Standards and Technology (NIST) and within the ASTM Committee F45 on Driverless Automatic Guided Industrial Vehicles. This includes standards for both terminology, F45.91, and for navigation performance test methods, F45.02. The paper defines terms that are being considered. Additionally, the paper describes navigation test methods that are near ballot and docking test methods being designed for consideration within F45.02. This includes the use of low cost artifacts that can provide alternatives to using relatively expensive measurement systems.

ASTM committee on corrosion of metals honors Dr David Silverman

ASTM committee on corrosion of metals honors Dr David Silverman

Progress in Additive Manufacturing

Additive manufacturing (AM) is among the fastest growing and most talked about manufacturing technologies on the planet. It is providing diverse opportunities for new product design and manufacturing. At GE, efforts such as the additively produced LEAP engine fuel nozzle and low-pressure turbine blade manufacturing are examples of how GE Aviation is leveraging these technologies in innovative ways. These are just a few illustrations of how AM is changing the manufacturing landscape and many others are described in the articles that follow. This rapid growth and investment poses several questions for the minerals, metals, and materials community: What exactly is ‘‘additive manufacturing?’’ Why has it captured the manufacturing industry imagination? How can the TMS community of materials and process technologists and leaders contribute to its growth and implementation? At its core, AM is a suite of technologies that ‘‘build’’ components using digital model data. The ASTM Committee F42 on AM Technologies has defined seven different process routes as being part of the field of AM. Each process has its own unique benefits and challenges that derive from the thermal and chemical processing cycle and the resulting microstructure. Any discussion of the technology needs to take into account the details of the resulting materials microstructure, surface roughness, and ability to maintain engineering tolerances, as well as implementation details about reliability and cost, and potential supply chain issues. The industrial excitement around this suite of processes is being driven by its capacity for empowering designers to focus on designing components for functionality rather than limitations of conventional processes such as casting, brazing, or forming processes. Furthermore, it is now enabling a whole new paradigm of rapid testing and product introduction wherein functional metal prototypes can be used for testing of individual components and manufacturing assembly processes (e.g., joining, forming, or machining). Using AM means product development cycles do not have to rely on traditional methods for manufacturing metallic prototypes, which can take months to produce. This leads to the key question: How can the minerals, metals, and materials community contribute to responsible, accelerated growth given the context of where the field is today? The key to industrial implementation for manufacturing technologies is a thorough understanding of the synergistic interaction of materials and processes. For AM, there are currently only a handful of materials and processes that are well understood, such as the previously mentioned laser powder-bed fusion of cobalt chrome and electron beam powder-bed fusion of titanium aluminide. To realize the full potential of AM, further maturation of the processing-structure-properties linkages will be required in a broader set of metal alloys and for many more processing approaches. When that happens, AM adoption will accelerate as industrial designers become empowered to select tailored material and process combinations that drive performance improvement for demanding applications. This special topic, Progress in AM, strives to meet that challenge by presenting a collection of articles that cover a broad spectrum of material systems and AM processing approaches including original research topics and application reviews. To download any of the articles, follow the URL: http://link.spring er.com/journal/11837/67/3/page/1 to the table of contents page for the March 2015 issue (Vol. 67, No. 3). In ‘‘Metallurgical and Mechanical Evaluation of 4340 Steel Produced by Direct Metal Laser Sintering,’’ by Elias Jelis, Matthew Clemente, Stacey Kerwien, Nuggehalli M. Ravindra, and Michael R. Hespos, the authors present new work on the Edward D. Herderick is the guest editor for the Process Technology and Modeling Committee of the TMS Materials Processing & Manufacturing Division, and coordinator of the topic Progress in Additive Manufacturing in this issue. JOM, Vol. 67, No. 3, 2015