Beyond 3D Printing: The New Dimensions of Additive Fabrication

Additive fabrication, often referred to as 3D printing, is the construction of objects by adding material. This stands in contrast to subtractive methods, which involve removing material by means of milling or cutting. Although additive fabrication and 3D printing are thought of as synonymous, additive fabrication encompasses a far broader range of construction, and new dimensions are on the horizon, inspiring innovation across scales and applications. For instance, can you print a full-scale building? How can we structurally engineer color and alter on the nanoscale? If trees grow additively, can biology be designed for fabrication

Novel applications of multipurpose robotic arms spanning design fabrication, utility, and art

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 204-208).This work investigates, defines, and expands on the use of robotic arms in digital fabrication, design, and art through methods including 3D printing, milling, sculpting, functionally graded fabrication, construction-scale additive manufacturing, jammable granular system design, light painting, and volumetric sensing. While most current applications of robotics in manufacturing rely on repetitive automation and assembly tasks, the flexibility, dexterity, and precision of industrial robotic arms provide for design opportunities of multi-functionary roles. Through exploration and demonstration, a multipurpose fabrication platform was developed using a KUKA KR5 sixx R850 robotic arm. The platform is capable of conventional manufacturing techniques spanning the three traditional fabrication categories: additive, subtractive, and formative. Case studies and digital design fabrication protocols were developed as part of the robotic platform to demonstrate these three types of fabrication including 3D printing, multi-axis milling, and clay sculpting, respectively. Compound processes, such as combining 3D printing and milling, were developed that offer product-, and process-based improvements over standalone techniques. The benefits and drawbacks of a multi-fabrication platform are discussed, including cost, physical footprint, resolution, and flexibility. In addition to replicating conventional manufacturing techniques with a single robotic platform, several novel applications were developed which take advantage of the flexibility of an arm system. First, functionally graded 3D printing was explored using concrete through which density gradients were shown to achieve higher structural efficiency. A novel construction-scale additive manufacturing process capable of 3D printing building components was developed. Secondly, direct recycling 3D printing was developed where waste thermoplastic products are transformed into feedstock and printed into new components within a single operation. Work conducted on jammed granular structures, where external pressure controls system stiffness and strength, resulted in several new formative fabrication possibilities. Combined with robotics, waste-free digital casting using jammable materials was enabled along with a variety of design projects including the design of robotic arms themselves. Finally, the use of robotic arms for fabrication of material and environmental properties without mechanical force transfer was explored. Coined immaterial fabrication,t his fabrication category captures methods that do not fall within the definitions of additive, subtractive, or formative processes. Work produced in this area includes a volumetric sensing technique and robotic light paintings that reveal thermal, electromagnetic, and optical fields.by Steven J. Keating.S.M

Design and analysis of a robust, low-cost, highly articulated manipulator enabled by jamming of granular media

Hyper-redundant manipulators can be fragile, expensive, and limited in their flexibility due to the distributed and bulky actuators that are typically used to achieve the precision and degrees of freedom (DOFs) required. Here, a manipulator is proposed that is robust, high-force, low-cost, and highly articulated without employing traditional actuators mounted at the manipulator joints. Rather, local tunable stiffness is coupled with off-board spooler motors and tension cables to achieve complex manipulator configurations. Tunable stiffness is achieved by reversible jamming of granular media, which-by applying a vacuum to enclosed grains-causes the grains to transition between solid-like states and liquid-like ones. Experimental studies were conducted to identify grains with high strength-to-weight performance. A prototype of the manipulator is presented with performance analysis, with emphasis on speed, strength, and articulation. This novel design for a manipulator-and use of jamming for robotic applications in general-could greatly benefit applications such as human-safe robotics and systems in which robots need to exhibit high flexibility to conform to their environments.United States. Defense Advanced Research Projects Agency (Maximum Mobility and Manipulation Program

Grown, Printed, and Biologically Augmented: An Additively Manufactured Microfluidic Wearable, Functionally Templated for Synthetic Microbes

Despite significant advances in synthetic biology at industrial scales, digital fabrication challenges have, to date, precluded its implementation at the product scale. We present, Mushtari, a multimaterial 3D printed fluidic wearable designed to culture microbial communities. Thereby we introduce a computational design environment for additive manufacturing of geometrically complex and materially heterogeneous fluidic channels. We demonstrate how controlled variation of geometrical and optical properties at high spatial resolution can be achieved through a combination of computational growth modeling and multimaterial bitmap printing. Furthermore, we present the implementation, characterization, and evaluation of support methods for creating product-scale fluidics. Finally, we explore the cytotoxicity of 3D printed materials in culture studies with the model microorganisms, Escherichia coli and Bacillus subtilis. The results point toward design possibilities that lie at the intersection of computational design, additive manufacturing, and synthetic biology, with the ultimate goal of imparting biological functionality to 3D printed products.National Science Foundation (U.S.) (DGE1144152)United States. Department of Energy (DE-SC0012658

A unitary test of the Ratios Conjecture

The Ratios Conjecture of Conrey, Farmer and Zirnbauer predicts the answers to numerous questions in number theory, ranging from n-level densities and correlations to mollifiers to moments and vanishing at the central point. The conjecture gives a recipe to generate these answers, which are believed to be correct up to square-root cancelation. These predictions have been verified, for suitably restricted test functions, for the 1-level density of orthogonal and symplectic families of L-functions. In this paper we verify the conjecture's predictions for the unitary family of all Dirichlet $L$-functions with prime conductor; we show square-root agreement between prediction and number theory if the support of the Fourier transform of the test function is in (-1,1), and for support up to (-2,2) we show agreement up to a power savings in the family's cardinality.Comment: Version 2: 24 pages, provided additional details, fixed some small mistakes and expanded the exposition in place

A New Era in Extragalactic Background Light Measurements: The Cosmic History of Accretion, Nucleosynthesis and Reionization

(Brief Summary) What is the total radiative content of the Universe since the epoch of recombination? The extragalactic background light (EBL) spectrum captures the redshifted energy released from the first stellar objects, protogalaxies, and galaxies throughout cosmic history. Yet, we have not determined the brightness of the extragalactic sky from UV/optical to far-infrared wavelengths with sufficient accuracy to establish the radiative content of the Universe to better than an order of magnitude. Among many science topics, an accurate measurement of the EBL spectrum from optical to far-IR wavelengths, will address: What is the total energy released by stellar nucleosynthesis over cosmic history? Was significant energy released by non-stellar processes? Is there a diffuse component to the EBL anywhere from optical to sub-millimeter? When did first stars appear and how luminous was the reionization epoch? Absolute optical to mid-IR EBL spectrum to an astrophysically interesting accuracy can be established by wide field imagingat a distance of 5 AU or above the ecliptic plane where the zodiacal foreground is reduced by more than two orders of magnitude.Comment: 7 pages; Science White Paper for the US Astro 2010-2020 Decadal Survey. If interested in further community-wide efforts on this topic please contact the first autho

Reliability of a smartphone goniometer app compared with traditional goniometer for measuring passive motion at the first metatarsophalangeal joint

BACKGROUND: Adequate sagittal plane motion of the first metatarsalphalangeal joint (1st MTPJ) is important during normal gait and goniometric measurement is commonly used as a diagnostic and outcome assessment tool. We aimed to determine the intra and inter-rater reliability together with the concurrent validity of a universal plastic goniometer (UG) and a smartphone applicationlication (Dr G) for the measurement of dorsiflexion at the 1st MTPJ. METHODS: Measurement of joint position and passive range of motion of the 1st MTPJ dorsiflexion was compared using a UG and DrG goniometer. A double-blind repeated measures design was utilized, with intraclass correlation coefficient (ICC) used to determine levels of reliability. RESULTS: For joint position good intra-rater reliability (ICC >0.861) and good inter-rater reliability (ICC >0.823) was noted. However, the Dr G application consistently measured lower angles (mean 27.8° (SD 8.37)) than the UG (mean 32° (SD 11.7)) and these associations were significant (r = 0.399, p < 0.001). For passive range of motion, the mean total range of dorsiflexion motion (from maximum plantarflexed position to maximum dorsiflexed position) was 82.8° (SD 12.2) for the UG and 82.9° (SD 11.3) for the Dr G application. Both instruments demonstrated high levels of intra-rater reliability (ICC >0.809). Inter-rater reliability was moderate to good for the UG (ICC 0.693 (95 % CI 0.580 to 0.788)) and good for the Dr G application (ICC 0.708 (95 % CI 0.597 to 0.799)). CONCLUSIONS: Moderate to high intra and inter-rater reliability of joint position and passive 1st MTPJ motion can be achieved with traditional and smartphone-based goniometric measurement. The Dr G application may provide a slightly higher reliability, but devices should not be used inter-changeably as significant variation in measurement between devices may occur. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13047-015-0088-3) contains supplementary material, which is available to authorized users

Management of adverse events associated with idelalisib treatment: expert panel opinion

Idelalisib is a first-in-class selective, oral, phosphatidylinositol 3-kinase delta (PI3Kδ) inhibitor approved for the treatment of several types of blood cancer. Idelalisib has demonstrated significant efficacy and a tolerable safety profile in clinical trials. However, the US prescribing information contains a black box warning for fatal and/or severe diarrhea or colitis, hepatotoxicity, pneumonitis and intestinal perforation. An expert panel was convened to review the pathology of these treatment-emergent adverse events (TEAEs) to propose key management tools for patients receiving idelalisib therapy. This article provides an overview of idelalisib TEAEs reported in clinical trials, and a summary of the panel's recommendations for identification and management of idelalisib treatment-emergent diarrhea or colitis as well as a discussion of transaminitis and pneumonitis. For idelalisib-related diarrhea or colitis (including unresolved grade 2 and grade ≥ 3), after exclusion of infectious causes, the panel recommends individualized treatment with budesonide or oral or intravenous steroid therapy

Global Spatial Risk Assessment of Sharks Under the Footprint of Fisheries

Effective ocean management and conservation of highly migratory species depends on resolving overlap between animal movements and distributions and fishing effort. Yet, this information is lacking at a global scale. Here we show, using a big-data approach combining satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively) and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of high-seas fishing effort. Results demonstrate an urgent need for conservation and management measures at high-seas shark hotspots and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real time, dynamic management