9,698 research outputs found

    A magneto-sensitive skin for robots in space

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    The development of a robot arm proximity sensing skin that can sense intruding objects is described. The purpose of the sensor would be to prevent the robot from colliding with objects in space including human beings. Eventually a tri-mode system in envisioned including proximity, tactile, and thermal. To date the primary emphasis was on the proximity sensor which evolved from one based on magneto-inductive principles to the current design which is based on a capacitive-reflector system. The capacitive sensing element, backed by a reflector driven at the same voltage and in phase with the sensor, is used to reflect field lines away from the grounded robot toward the intruding object. This results in an increased sensing range of up to 12 in. with the reflector on compared with only 1 in. with it off. It is believed that this design advances the state-of-the-art in capacitive sensor performance

    Magneto-inductive skin sensor for robot collision avoidance: A new development

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    Safety is a primary concern for robots operating in space. The tri-mode sensor addresses that concern by employing a collision avoidance/management skin around the robot arms. This rf-based skin sensor is at present a dual mode (proximity and tactile). The third mode, pyroelectric, will complement the other two. The proximity mode permits the robot to sense an intruding object, to range the object, and to detect the edges of the object. The tactile mode permits the robot to sense when it has contacted an object, where on the arm it has made contact, and provides a three-dimensional image of the shape of the contact impression. The pyroelectric mode will be added to permit the robot arm to detect the proximity of a hot object and to add sensing redundancy to the two other modes. The rf-modes of the sensing skin are presented. These modes employ a highly efficient magnetic material (amorphous metal) in a sensing technique. This results in a flexible sensor array which uses a primarily inductive configuration to permit both capacitive and magnetoinductive sensing of object; thus optimizing performance in both proximity and tactile modes with the same sensing skin. The fundamental operating principles, design particulars, and theoretical models are provided to aid in the description and understanding of this sensor. Test results are also given

    Predictions from non trivial Quark-Lepton complementarity

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    The complementarity between the quark and lepton mixing matrices is shown to provide robust predictions. We obtain these predictions by first showing that the matrix V_M, product of the quark (CKM) and lepton (PMNS) mixing matrices, may have a zero (1,3) entry which is favored by experimental data. We obtain that any theoretical model with a vanishing (1,3) entry of V_M that is in agreement with quark data, solar, and atmospheric mixing angle leads to θ13PMNS=(92+1)\theta_{13}^{PMNS}=(9{^{+1}_{-2}})^\circ. This value is consistent with the present 90% CL experimental upper limit. We also investigate the prediction on the lepton phases. We show that the actual evidence, under the only assumption that the correlation matrix V_M product of CKM and PMNS has a zero in the entry (1,3), gives us a prediction for the three CP-violating invariants J, S_1, and S_2. A better determination of the lepton mixing angles will give stronger prediction for the CP-violating invariants in the lepton sector. These will be tested in the next generation experiments. Finally we compute the effect of non diagonal neutrino mass in "l_i -> l_j gamma" in SUSY theories with non trivial Quark-Lepton complementarity and a flavor symmetry. The Quark-Lepton complementarity and the flavor symmetry strongly constrain the theory and we obtain a clear prediction for the contribution to "mu -> e gamma" and the "tau" decays "tau -> e gamma" and "tau -> mu gamma". If the Dirac neutrino Yukawa couplings are degenerate but the low energy neutrino masses are not degenerate, then the lepton decays are related among them by the V_M entries. On the other hand, if the Dirac neutrino Yukawa couplings are hierarchical or the low energy neutrino masses are degenerate, then the prediction for the lepton decays comes from the CKM hierarchy.Comment: 15 pages, 5 figures, ws-ijmpa class included, Proceedings of the CTP Symposium on Sypersymmetry at LH

    Economics of nitrogen and integrated weed management in dry seeded rice

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    Dry-seeded rice (DSR) is an emerging production technology in many Asian countries, whose profitability is higher than puddled transplanted rice. However, weed infestations are severe in the DSR. To increase the competitiveness with weeds and achieve the yield potential of rice, weed management in DSR needs an integration of herbicides and higher nitrogen (N) fertilizer rates. Field experiments were conducted in the aman (wet season) 2012 and 2013 in Bangladesh to evaluate the effect of N rates (0, 80, 120, and 160 kg ha) and weed control methods [one hand weeding (HW); pendimethalin 1000 g ai ha followed by (fb) ethoxysulfuron 20 g ai ha; pendimethalin fb ethoxysulfuron fb one HW; and weed-free] on weed growth and crop yield in DSR. The experiment was arranged in a split-plot design with three replications. The highest grain yield (5.3 to 5.5 t ha) was recorded in the season-long manual weed free treatment when N rate was160 kg ha; however, because of the high cost of labor, this method was not profitable. The use of pendimethalin fb ethoxysulfuron fb one HW effectively controlled weeds and produced a similar yield with the weed-free treatment for all levels of N. However, weed management cost was also higher because of the involvement of one HW. Although pendimethalin fb ethoxysulfuron treatment had always lower yielded than the pendimethalin fb ethoxysulfuron fb one HW, grain yield increased and net profit was similar when N rate increased from 120 to 160 kg ha. Considering weed control efficiency, yield, and economics, pendimethalin fb ethoxysulfuron fb one HW with 120 kg N ha may be recommended to growers. However, if laborers are not available for hand weeding, pendimethalin fb ethoxysulfuron with 160 kg N ha is the best option to achieve high yield in DSR

    Single grain (LRE)-Ba-Cu-O superconductors fabricated by top seeded melt growth in air

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    We have recently reported a practical processing method for the fabrication in air of large, single grain (LRE)-Ba-Cu-O [where LRE Nd, Sm, Eu and Gd] bulk superconductors that exhibit high Tc and high Jc. The process is based initially on the development of a new type of generic seed crystal that can promote effectively the epitaxial nucleation of any (RE)-Ba-Cu-O system and, secondly, by suppressing the formation of (LRE)/Ba solid solution in a controlled manner within large LRE-Ba-Cu-O grains processed in air. In this paper we investigate the degree of homogeneity of large grain Sm-Ba-Cu-O superconductors fabricated by this novel process. The technique offers a significant degree of freedom in terms of processing parameters and reproducibility in the growth of oriented single grains in air and yields bulk samples with significantly improved superconducting and field-trapping properties compared to those processed by conventional top seeded melt growth (TSMG)

    The Parallel Persistent Memory Model

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    We consider a parallel computational model that consists of PP processors, each with a fast local ephemeral memory of limited size, and sharing a large persistent memory. The model allows for each processor to fault with bounded probability, and possibly restart. On faulting all processor state and local ephemeral memory are lost, but the persistent memory remains. This model is motivated by upcoming non-volatile memories that are as fast as existing random access memory, are accessible at the granularity of cache lines, and have the capability of surviving power outages. It is further motivated by the observation that in large parallel systems, failure of processors and their caches is not unusual. Within the model we develop a framework for developing locality efficient parallel algorithms that are resilient to failures. There are several challenges, including the need to recover from failures, the desire to do this in an asynchronous setting (i.e., not blocking other processors when one fails), and the need for synchronization primitives that are robust to failures. We describe approaches to solve these challenges based on breaking computations into what we call capsules, which have certain properties, and developing a work-stealing scheduler that functions properly within the context of failures. The scheduler guarantees a time bound of O(W/PA+D(P/PA)log1/fW)O(W/P_A + D(P/P_A) \lceil\log_{1/f} W\rceil) in expectation, where WW and DD are the work and depth of the computation (in the absence of failures), PAP_A is the average number of processors available during the computation, and f1/2f \le 1/2 is the probability that a capsule fails. Within the model and using the proposed methods, we develop efficient algorithms for parallel sorting and other primitives.Comment: This paper is the full version of a paper at SPAA 2018 with the same nam

    Research Notes : India : Intra-plant variation in mutation frequency and spectrum in soybean

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    Upadhyaya (1976) observed that the number of mutant plants was exceedingly low in segregating M2 progenies in soybean. In M3 progenies of normal M2 plants, the number of segregating progenies was also not very high as compared with nonsegregating progenies. But, all the segregating progenies in MJ generation showed an excellent fit to the 3 normal:l mutant ratio, indicating mutant as a monogenic recessive trait. Such a situation was encountered in many cases of albino, yellow leaf, crinkled leaf, and sterile mutants

    Magnetic properties of polypyrrole - coated iron oxide nanoparticles

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    Iron oxide nanoparticles were prepared by sol -gel process. Insitu polymerization of pyrrole monomer in the presence of oxygen in iron oxide ethanol suspension resulted in a iron oxide - polypyrrole nanocomposite. The structure and magnetic properties were investigated for varying pyrrole concentrations. The presence of the gamma - iron oxide phase and polypyrrole were confirmed by XRD and FTIR respectively. Agglomeration was found to be comparatively much reduced for the coated samples, as shown by TEM. AC susceptibility measurements confirmed the superparamagnetic behaviour. Numerical simulations performed for an interacting model system are performed to estimate the anisotropy and compare favourably with experimental results.Comment: 11 pages,8 figure

    Low Energy Solar Neutrinos and Spin Flavour Precession

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    The possibility that the Gallium data effectively indicates a time modulation of the solar active neutrino flux in possible connection to solar activity is examined on the light of spin flavour precession to sterile neutrinos as a subdominant process in addition to oscillations. We distinguish two sets of Gallium data, relating them to high and low solar activity. Such modulation affects principally the low energy neutrinos (pppp and 7Be^7 Be) so that the effect, if it exists, will become most clear in the forthcoming Borexino and LENS experiments and will provide evidence for a neutrino magnetic moment. Using a model previously developed, we perform two separate fits in relation to low and high activity periods to all solar neutrino data. These fits include the very recent charged current spectrum from the SNO experiment. We also derive the model predictions for Borexino and LENS experiments.Comment: 20 pages, 5 ps figures, 1 eps figure, final version to be published in JHE

    CONTENT BASED INFORMATION RETRIEVAL FOR DIGITAL LIBRARY USING DOCUMENT IMAGE

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    In the recent year, the using of mobile devices has perceive an emerging need for improving the user experience of digital library for search, with various applications such as education, location search and product retrieval, There simply compare the query to the databases images; those are match that images are retrieve from the database, searching and response time of delivery staying a challenging issues in mobile document search previously lots of work has been done on search engine, retrieving the document from the database without analyzed the image. In The proposed method, Information retrieval for image based query automatically with a mobile document information retrieval framework, consisting of a FP-growth is proposed finding frequent pattern from the retrieve document to optimize the result
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