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

Improving the athletic performance of highly skilled college volleyball players through the use of a videotape treatment package

A multiple baseline across behaviors design was used to test the effectiveness of a treatment package involving the use of a videotape recorder to improve the performance of college women volleyball players. The subjects were four highly skilled athletes, as evidenced by thei.r participation in the University of the Pacific volleyball program, ranked second nationally during the 1980-81 season. The treatment package consisted of the following: (a) zooming in with a video camera on particular aspects of the players\u27 performances; (b) attempts to change only one aspect of the performance of a skill rather than the entire skill; (c) cueing and corrective feedback provided by the coach during the players\u27 viewing of the resulting videotapes; (d) the players immediately correcting their errors in performance after viewing the videotapes and (e) multiple viewings by the players of videotapes of their correct performances of the volleyball skills. The results indicated that all of the subjects benefited from the videotape treatment package. Two of the players showed improvement in the two volleyball skills for which the treatment was given. The other two players showed improvement in one of the two volleyball skills for which the treatment was given. For three of the four players their improved practice performances with the videotape treatment also resulted in improved performances during scrimmages for at least one of the two target behaviors

Relativistic calculations of angular dependent photoemission time delay

Angular dependence of photoemission time delay for the valence $np_{3/2}$ and $np_{1/2}$ subshells of Ar, Kr and Xe is studied in the dipole relativistic random phase approximation. Strong angular anisotropy of the time delay is reproduced near respective Cooper minima while the spin-orbit splitting affects the time delay near threshold

Balancing Independence and Accountability: Proposals to Reform Special Counsel Investigations

Investigations of the president and other high-ranking officials must be free from political interference yet cannot devolve into “runaway” inquiries. This report recommends reforms to the rules for every stage of special counsel investigations. Among the proposals is a requirement that federal judges oversee the attorney general’s appointment and removal of special counsels. Additionally, a special counsel should be mandatory when the president is suspected of a crime and reports on investigations should go directly to Congress

Low-input, high quality legume hays for north Queensland

Perennial herbaceous legumes grown for hay can improve beef and dairy production in north Queensland through providing affordable high-quality (digestible protein) dry season feed. Eleven Arachis ecotypes (A. pintoi (5), A. glabrata (3), A. paraguariensis (2) and A. kretschmeri (1)), two Stylosanthes guianensis varieties and two commercially recommended Medicago sativa varieties were grown for hay under irrigation using standardised populations in replicated small-plots over two wet seasons (summer) and compared for dry matter production and fodder quality using 8 week cutting cycles. All initially grew well but M. sativa plants were damaged by leaf and stem diseases during wet summer periods reducing leaf and stem growth and resulting in open, weedy stands; the Arachis and Stylosanthes were relatively unaffected and exhibited strong summer-dominant growth throughout the study. There were significant species and varietal differences in biomass production and some A. pintoi, M. sativa and S. guianensis produced over 30 T DM (stem plus leaf above 5 cm cut height) over 19 months. Arachis glabrata also yielded well (16-18 T DM) following a prolonged establishment phase. Feed quality was high for all legumes compared, and overall best in the Arachis spp., with crude protein percentages mostly above 16% and high levels of protein and carbohydrate rumen degradability

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

Texture Development in YBa 2 Cu 3 O x by Hot Extrusion and Hot-Pressing

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66453/1/j.1151-2916.1987.tb04929.x.pd

Human Galectin-9 Is a Potent Mediator of HIV Transcription and Reactivation.

Identifying host immune determinants governing HIV transcription, latency and infectivity in vivo is critical to developing an HIV cure. Based on our recent finding that the host factor p21 regulates HIV transcription during antiretroviral therapy (ART), and published data demonstrating that the human carbohydrate-binding immunomodulatory protein galectin-9 regulates p21, we hypothesized that galectin-9 modulates HIV transcription. We report that the administration of a recombinant, stable form of galectin-9 (rGal-9) potently reverses HIV latency in vitro in the J-Lat HIV latency model. Furthermore, rGal-9 reverses HIV latency ex vivo in primary CD4+ T cells from HIV-infected, ART-suppressed individuals (p = 0.002), more potently than vorinostat (p = 0.02). rGal-9 co-administration with the latency reversal agent "JQ1", a bromodomain inhibitor, exhibits synergistic activity (p<0.05). rGal-9 signals through N-linked oligosaccharides and O-linked hexasaccharides on the T cell surface, modulating the gene expression levels of key transcription initiation, promoter proximal-pausing, and chromatin remodeling factors that regulate HIV latency. Beyond latent viral reactivation, rGal-9 induces robust expression of the host antiviral deaminase APOBEC3G in vitro and ex vivo (FDR<0.006) and significantly reduces infectivity of progeny virus, decreasing the probability that the HIV reservoir will be replenished when latency is reversed therapeutically. Lastly, endogenous levels of soluble galectin-9 in the plasma of 72 HIV-infected ART-suppressed individuals were associated with levels of HIV RNA in CD4+ T cells (p<0.02) and with the quantity and binding avidity of circulating anti-HIV antibodies (p<0.009), suggesting a role of galectin-9 in regulating HIV transcription and viral production in vivo during therapy. Our data suggest that galectin-9 and the host glycosylation machinery should be explored as foundations for novel HIV cure strategies

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

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