3,336 research outputs found

    Heat-treatment of metal parts facilitated by sand embedment

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    Embedding metal parts of complex shape in sand contained in a steel box prevents strains and warping during heat treatment. The sand not only provides a simple, inexpensive support for the parts but also ensures more uniform distribution of heat to the parts

    Re-feedback: freedom with accountability for causing congestion in a connectionless internetwork

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    This dissertation concerns adding resource accountability to a simplex internetwork such as the Internet, with only necessary but sufficient constraint on freedom. That is, both freedom for applications to evolve new innovative behaviours while still responding responsibly to congestion; and freedom for network providers to structure their pricing in any way, including flat pricing. The big idea on which the research is built is a novel feedback arrangement termed ‘re-feedback’. A general form is defined, as well as a specific proposal (re-ECN) to alter the Internet protocol so that self-contained datagrams carry a metric of expected downstream congestion. Congestion is chosen because of its central economic role as the marginal cost of network usage. The aim is to ensure Internet resource allocation can be controlled either by local policies or by market selection (or indeed local lack of any control). The current Internet architecture is designed to only reveal path congestion to end-points, not networks. The collective actions of self-interested consumers and providers should drive Internet resource allocations towards maximisation of total social welfare. But without visibility of a cost-metric, network operators are violating the architecture to improve their customer’s experience. The resulting fight against the architecture is destroying the Internet’s simplicity and ability to evolve. Although accountability with freedom is the goal, the focus is the congestion metric, and whether an incentive system is possible that assures its integrity as it is passed between parties around the system, despite proposed attacks motivated by self-interest and malice. This dissertation defines the protocol and canonical examples of accountability mechanisms. Designs are all derived from carefully motivated principles. The resulting system is evaluated by analysis and simulation against the constraints and principles originally set. The mechanisms are proven to be agnostic to specific transport behaviours, but they could not be made flow-ID-oblivious

    Partial-Wave Analysis of Single-Pion Production Reactions

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    We present an overview of our efforts to analyze pion-nucleon elastic scattering data, along with data from related photo- and electroproduction reactions, in order to study the baryon spectrum. We then focus on the Delta(1232) resonance. Fits to pion photo- and electroproduction data have been used to extract values for the R_EM = E2/M1 and R_SM = S2/M1 ratios as functions of Q^2. These results are compared to other recent determinations.Comment: 7 pages, 9 figures, the Shape of Hadrons Workshop Proceedings (27-29 April, 2006 Athens, Greece

    Evaluation of Sediment and Nutrient Loss during the Revegetation of Mississippi Roadsides

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    Runoff during the revegetation of roadsides can transport sediment and nutrients offsite, leading to surface water quality reductions. Two field experiments were conducted near Starkville, MS in 2011 and 2012 to evaluate the influence of N and P sources and rates, fertilization timing, and mulch type on vegetative establishment and nutrient and sediment runoff losses. Stainless steel runoff frames (0.75 x 2.0 m) were installed on 10% and 15% slopes for Experiment I and Experiment II, respectively. A bahiagrass (Paspalum notatum Flugge), tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.], sericea lespedeza [Lespedeza cuneata (Dum. Cours.) G. Don], and common bermudagrass [Cynodon dactylon (L.) Pers.] mixture was seeded within each frame during Experiment I. Crimson clover (Trifolium incarnatum L.) was added for Experiment II. Experiment I treatments consisted of 73.5 or 147 kg N ha-1 as 13-13-13, poultry litter, ammonium nitrate, stabilized urea, polymer coated urea, or diammonium phosphate. Experiment II treatments consisted of wheat straw and six hydromulches; paper fiber, wood fiber, wood/paper fiber blend, flexible growth medium (FGM), extended term-FGM (ET-FGM), bonded fiber matrix (BFM). Runoff from natural and simulated rainfall was analyzed for PO43--P, total P (TP), NH4+-N, NO3- -N, total N (TN), and total solids (TS). Experiment I results suggest the greatest N and P runoff losses occurred during the first runoff event following fertilization. Splitting 147 kg N ha-1 into two equal applications increased nutrient losses compared to one application. Application of organic plus inorganic P increased PO43--P in runoff compared to inorganic P alone. Experiment II results indicate straw was the most effective mulch for increasing vegetative establishment and limiting solids and nutrients in runoff. However, lack of fertilizer prill dissolution may have influenced nutrient runoff losses during dry conditions. The FGM, ET-FGM, and BFM mulch treatments were more effective than the paper, wood, and paper/wood fiber treatments in reducing solids and nutrients in runoff. It was apparent during both experiments that timing, intensity, and duration of rainfall events following fertilization have an influence on runoff losses. However, further research is needed to quantify the influence of those rainfall parameters

    Letter from the Editor

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    Results from the Analysis of Crystal Ball Meson Production Measurements at BNL

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    The Crystal Ball spectrometer, with its nearly complete angular coverage, is an efficient detector of photon and neutron final states. While installed in the C6 beamline of the Alternating Gradient Synchrotron (AGS) of Brookhaven National Laboratory (BNL), this feature was used in a series of precise measurements of reactions with all-neutral final states. Here we concentrate on the analysis of data from the pion-induced reactions: pi- p --> gamma n, pi- p --> pi0 n, pi- p --> eta n, and pi- p --> pi0 pi0 n.Comment: Conference contribution to MESON 2006 - Krakow, Pola
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