12,517 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

    7Be ^7 Be Neutrino Signal Variation in KamLAND

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    Large Mixing Angle (LMA) neutrino oscillation is the main solution for the long-standing Solar Neutrino Problem (SNP). Whether there is any subdominant effect accompanying the dominant LMA solution can not be ruled out at the moment, but will be settled by the forthcoming data from highly skilled real time experiments targeting essentially the low energy domain of solar neutrinos. Assuming a subdominant effect converting one of the active neutrinos into a sterile partner in the varying solar field with changing sunspot activity, we performed field-profile-independent predictions for 7Be^7 Be neutrino signal variation, which might be tested in the KamLAND's future solar neutrino detection program. We found that after a substantial reduction of background and running of KamLAND solar mode through the sunspot maximum period (around 2010 - 2012), when the solar field at the resonance may vary from few kGkG to 300 kG300~kG, the subdominant time variation effect might be clearly visible (more than 5σ5\sigma) for 7Be^7 Be neutrinos.Comment: 12 pages, 4 figures, typos corrected. To appear in JHE

    QQˉQ\bar Q (Q{b,c}Q\in \{b, c\}) spectroscopy using Cornell potential

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    The mass spectra and decay properties of heavy quarkonia are computed in nonrelativistic quark-antiquark Cornell potential model. We have employed the numerical solution of Schr\"odinger equation to obtain their mass spectra using only four parameters namely quark mass (mcm_c, mbm_b) and confinement strength (AccˉA_{c\bar c}, AbbˉA_{b\bar b}). The spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction are computed perturbatively to determine the mass spectra of excited SS, PP, DD and FF states. Digamma, digluon and dilepton decays of these mesons are computed using the model parameters and numerical wave functions. The predicted spectroscopy and decay properties for quarkonia are found to be consistent with available experimental observations and results from other theoretical models. We also compute mass spectra and life time of the BcB_c meson without additional parameters. The computed electromagnetic transition widths of heavy quarkonia and BcB_c mesons are in tune with available experimental data and other theoretical approaches

    Break Even Analysis of Mining Projects

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    The economics of the resources industry are unique. All mining is subject to uncertainties not applicable to other industries. Every mine is different. Industry economics are difficult to quantify and categorize. Information is very costly. In major mining countries, there is now a real dichotomy. The products of the minerals industry are essential primary ingredients in almost everything used in an advanced society, yet their availability is often taken for granted. In the developed world, the value of mining is increasingly being called into question. The difficulty in making profits is compounded by political uncertainties and environmental restrictions on top of the uncertainties created by nature. Costing and evaluation of any mining development are necessarily based on a specific plan, which has to be prepared assuming certain ore body characteristics. However ore bodies are seldom clearly defined, and the effort to find and delineate them is itself an economically significant task. The economics of mining will determine what parts are or are not included in the definition of ore. When mine economics change, the amount of material in the ground does not change, but the amount of economically viable ore does change. The amount of economically viable ore is also dependent on the assumptions used for its calculation and can change with a change in assumptions. The break-even point for a product is the point where total revenue received equals the total costs associated with the sale of the product. It has certain assumptions such as, selling prices will remain constant at all sales level, there is a linear relationship between sales volume and costs and production and sales quantities are equal. At the same time it suffers from certain limitations as break-even analysis is only a supply side (i.e. costs only) analysis, as it tells you nothing about what sales are actually likely to be for the product at these various prices

    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

    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)

    Psychometric Properties of the Job Engagement Scale: A Cross-Country Analysis

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    Job engagement is a motivational construct that refers to the willingness of employees to invest their physical, emotional and cognitive energies in their jobs in a holistic and simultaneous manner. Researchers use the Job Engagement Scale (JES) to measure the above conceptualization of job engagement, whose application is recent in job engagement research and is based largely on Western samples. In order to examine how job engagement is perceived in Asian contexts, this exploratory study aimed to provide a cross-country analysis of psychometric properties of the JES. We utilized data from earlier research of the first author, which were collected from 347 Pakistani and 498 Malaysian employees worked at diverse organizations. Psychometric analyses with reliability and validity estimations were performed using the Structural Equation Modeling. Results showed good internal consistency reliability, convergent validity and factorial validity of the JES for both Pakistani and Malaysian samples. However, psychometric properties of the JES for Pakistan outperformed those for Malaysia in all the estimations. Implications for future use of the JES and limitations of the study are discussed

    Corneal Lymphatics: Role in Ocular Inflammation as Inducer and Responder of Adaptive Immunity

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    The normal cornea is devoid of lymphatic and blood vessels, thus suppressing both the afferent (lymphatic) and efferent (vascular) arms of the immune response–contributing to its ‘immune privilege’. Inflammation, however, negates this unique ‘immune’ and ‘angiogenic’ privilege of the cornea. Abnormal blood vessel growth from pre-existing limbal vessels into the cornea has been studied for many years, but it is only recently that the significance of new lymphatic vessels (lymphangiogenesis) in ocular inflammatory diseases has been demonstrated. Whereas blood vessels in inflamed ocular surface provide a route of entry for immune effector cells to the cornea, lymphatics facilitate the exit of antigen-presenting cells and antigenic material from the cornea to regional lymph nodes, thus promoting induction of adaptive immune response. This review summarizes the current evidence for lymphangiogenesis in the cornea, and describes its molecular mediators; and discusses the interface between corneal lymphangiogenesis and adaptive immunity. Furthermore, the pathophysiologic implications of corneal lymphangiogenesis in the setting of allo- and autoimmune-mediated corneal inflammation are discussed
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