8,404 research outputs found

    Hydraulic valve lifter remover

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    Threaded rod, mounted in tubular housing which is flanged and expandable at one end, removes valve lifter after removal of valve covers and push rods

    Improved quick-disconnect electrical connector

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    Electrical connector is fitted with an O ring, moisture-proof seal, is shielded in both the mated and unmated positions, and is equipped with one keying and three locking spheres

    Comparing Field Methods that Estimate Mobile–Immobile Model Parameters

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    Recent studies have used field techniques that estimate soil hydraulic and solute transport parameters. These methods utilize a tension infiltrometer to infiltrate either a single tracer or a series of tracers in order to estimate immobile water content (θim) and mass exchange coefficient (α) of the mobile–immobile solute transport model. The objective of this study was to compare two single tracer methods (basic and variance) with one multiple tracer method for estimating θim and α from data obtained on the same field soil location. Hydraulic conductivity (K(h 0)) was also estimated using these methods. Research was done at five interrow sites in a ridge-tilled corn (Zea mays L.) field, and the soil was mapped as a Nicollet series (fine-loamy, mixed, superactive, mesic, Aquic Hapludoll). The values of θim and α estimated by the multiple tracer method compared well with previously measured values using the same technique on the same field. The θim values for the multiple tracer technique were larger than values derived from the basic single tracer technique. The basic single tracer technique did not take into consideration a mass exchange between θim and the mobile water domain (θm). The α values were less variable for the multiple tracer method than for the single tracer-variance method. Values of immobile water fraction (θim/θ) for the multiple and basic single tracer techniques ranged from 0.30 to 0.52 and from 0.24 to 0.35, respectively. The values of α for the multiple and single tracer-variance techniques ranged from 0.06 to 0.9 d−1 and from 0.03 to 60 d−1, respectively. The volumetric water content (θ) changed considerably over the course of the experiment for the estimation of α using the single tracer-variance method; thus, the assumptions of this technique were compromised. The measured values of K(h 0) at the five sites ranged from 0.47 to 1.66 μm s−1 There was evidence that the basic single tracer method underestimated θim and overestimated θm, because this method considers α = 0 during the tracer application

    Preliminary results of fast neutron treatments in carcinoma of the pancreas

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    A group of 30 patients with adenocarcinoma of the pancreas including some patients with very advanced disease, were treated with the so-called mixed beam modality employing photon treatments three times per week and neutron treatments twice a week. Two hundred Rads or equivalent Rads (RBE 3.3) were given in daily fractions aiming at a total dose of 6000 Rads in 6 to 8 weeks. The treatments were well tolerated and significant palliation was achieved in 26 to 30 cases. Twelve months survival was 33 percent with a median survival of 7 months or 210 days. Treatment techniques and localization procedures are discussed

    Nitrous oxide emission from highland winter wheat field after long-term fertilization

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    Nitrous oxide (N<sub>2</sub>O) is an important greenhouse gas. N<sub>2</sub>O emissions from soils vary with fertilization and cropping practices. The response of N<sub>2</sub>O emission to fertilization of agricultural soils plays an important role in global N<sub>2</sub>O emission. The objective of this study was to assess the seasonal pattern of N<sub>2</sub>O fluxes and the annual N<sub>2</sub>O emissions from a rain-fed winter wheat (<i>Triticum aestivum</i> L.) field in the Loess Plateau of China. A static flux chamber method was used to measure soil N<sub>2</sub>O fluxes from 2006 to 2008. The study included 5 treatments with 3 replications in a randomized complete block design. Prior to initiating N<sub>2</sub>O measurements the treatments had received the same fertilization for 22 years. The fertilizer treatments were unfertilized control (CK), manure (M), nitrogen (N), nitrogen + phosphorus (NP), and nitrogen + phosphorus + manure (NPM). Soil N<sub>2</sub>O fluxes in the highland winter wheat field were highly variable temporally and thus were fertilization dependent. The highest fluxes occurred in the warmer and wetter seasons. Relative to CK, m slightly increased N<sub>2</sub>O flux while N, NP and NPM treatments significantly increased N<sub>2</sub>O fluxes. The fertilizer induced increase in N<sub>2</sub>O flux occurred mainly in the first 30 days after fertilization. The increases were smaller in the relatively warm and dry year than in the cold and wet year. Combining phosphorous and/or manure with mineral N fertilizer partly offset the nitrogen fertilizer induced increase in N<sub>2</sub>O flux. N<sub>2</sub>O fluxes at the seedling stage were mainly controlled by nitrogen fertilization, while fluxes at other plant growth stages were influenced by plant and environmental conditions. The cumulative N<sub>2</sub>O emissions were always higher in the fertilized treatments than in the non-fertilized treatment (CK). Mineral and manure nitrogen fertilizer enhanced N<sub>2</sub>O emissions in wetter years compared to dryer years. Phosphorous fertilizer offset 0.50 and 1.26 kg N<sub>2</sub>O-N ha<sup>−1</sup> increases, while manure + phosphorous offset 0.43 and 1.04 kg N<sub>2</sub>O-N ha<sup>−1</sup> increases by N fertilizer for the two observation years. Our results suggested that the contribution of single N fertilizer on N<sub>2</sub>O emission was larger than that of NP and NPM and that manure and phosphorous had important roles in offsetting mineral N fertilizer induced N<sub>2</sub>O emissions. Relative to agricultural production and N<sub>2</sub>O emission, manure fertilization (M) should be recommended while single N fertilization (N) should be avoided for the highland winter wheat due to the higher biomass and grain yield and lower N<sub>2</sub>O flux and annual emission in m than in N

    Modus Vivendi Beyond the Social Contract: Peace, Justice, and Survival in Realist Political Theory

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    This essay examines the promise of the notion of modus vivendi for realist political theory. I interpret recent theories of modus vivendi as affirming the priority of peace over justice, and explore several ways of making sense of this idea. I proceed to identify two key problems for modus vivendi theory, so conceived. Normatively speaking, it remains unclear how this approach can sustain a realist critique of Rawlsian theorizing about justice while avoiding a Hobbesian endorsement of absolutism. And conceptually, the theory remains wedded to a key feature of social contract theory: political order is conceived as based on agreement. This construes the horizontal tensions among individual or group agents in society as prior to the vertical, authoritative relations between authorities and their subjects. Political authority thereby appears from the start as a solution to societal conflict, rather than a problem in itself. I argue that this way of framing the issue abstracts from political experience. Instead I attempt to rethink the notion of modus vivendi from within the lived experience of political conflict, as oriented not primarily toward peace, but political survival. With this shift of perspective, the idea of modus vivendi shows us, pace Bernard Williams, that the “first political question” is not how to achieve order and stability, but rather: what can I live with

    Ultrahigh-temperature osumilite gneisses in southern Madagascar record combined heat advection and high rates of radiogenic heat production in a long-lived high-T orogen

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    We report the discovery of osumilite in ultrahigh‐temperature (UHT) metapelites of the Anosyen domain, southern Madagascar. The gneisses equilibrated at ~930°C/0.6 GPa. Monazite and zircon U–Pb dates record 80 Ma of metamorphism. Monazite compositional trends reflect the transition from prograde to retrograde metamorphism at 550 Ma. Eu anomalies in monazite reflect changes in fO_2 relative to quartz–fayalite–magnetite related to the growth and breakdown of spinel. The ratio Gd/Yb in monazite records the growth and breakdown of garnet. High rates of radiogenic heat production were the primary control on metamorphic grade at the regional scale. The short duration of prograde metamorphism in the osumilite gneisses (<29 ± 8 Ma) suggests that a thin mantle lithosphere (<80 km) or advective heating may have also been important in the formation of this high‐T, low‐P terrane

    Microturbulence studies in RFX-mod

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    Present-days Reversed Field Pinches (RFPs) are characterized by quasi-laminar magnetic configurations in their core, whose boundaries feature sharp internal transport barriers, in analogy with tokamaks and stellarators. The abatement of magnetic chaos leads to the reduction of associated particle and heat transport along wandering field lines. At the same time, the growth of steep temperature gradients may trigger drift microinstabilities. In this work we summarize the work recently done in the RFP RFX-mod in order to assess the existence and the impact upon transport of such electrostatic and electromagnetic microinstabilities as Ion Temperature Gradient (ITG), Trapped Electron Modes (TEM) and microtearing modes.Comment: Work presented at the 2010 Varenna workshop "Theory of Fusion Plasmas". To appear in Journal of Physics Conference Serie

    Feasibility and systems definition study for Microwave Multi-Application Payload (MMAP)

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    Work completed on three Shuttle/Spacelab experiments is examined: the Adaptive Multibeam Phased Array Antenna (AMPA) Experiment, Electromagnetic Environment Experiment (EEE) and Millimeter Wave Communications Experiment (MWCE). Results included the definition of operating modes, sequence of operation, radii of operation about several ground stations, signal format, foot prints of typical orbits and preliminary definition of ground and user terminals. Conceptual hardware designs, Spacelab interfaces, data handling methods, experiment testing and verification studies were included. The MWCE-MOD I was defined conceptually for a steerable high gain antenna
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