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1

Wilsonville Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama. Topical report No. 10, thermal stress analysis  

Science.gov (United States)

The thermal dissolver, the main reactor of the SRC unit, has suffered a recurring problem. Specifically, it has been observed that whenever the reactor vessel is cooled to below 400/sup 0/F, its bottom head gasket leaks. An analysis of the thermal stress induced in the gasket, owing to transients across the bottom head flange, was sought. The analysis was facilitated by judiciously dividing a symmetric section of the reactor into 79 differential elements. Heat balances have been developed around each element. A numerical technique, the backward finite-difference approach, was employed to obtain the thermal behavior across the bottom head flange as a function of reactor heat-up time. The analysis performed affords an explanation for the failure of the gasket. Based on results of this work, recommendations have been suggested to provide the gasket and bolt stress requirements that are necessary to avoid ...

1983-08-01

2

Fireplace door  

Energy Technology Data Exchange (ETDEWEB)

A fireplace door assembly having doors pivotally mounted on a frame to be mounted on the opening of a fireplace. The doors are mounted on hinges that provide adjustment along a vertical axis of rotation and the front of the frame. An adjustable fire resistant gasket is used for an air seal. A gravity operated latch is provided to maintain the door in a closed position.

1985-05-07

3

40 CFR 63.322 - Standards.  

Science.gov (United States)

...Filter gaskets and seatings; (4) Pumps; (5) Solvent tanks and containers; (6) Water separators; (7) Muck cookers; (8) Stills; (9) Exhaust dampers; (10) Diverter valves; and (11) All Filter housings. (l)...

2009-07-01

4

Failure criteria and fission products trapping effect at containment penetrations under severe accident conditions (2)  

Energy Technology Data Exchange (ETDEWEB)

Since the integrity of the containment penetrations was confirmed under accident management (AM) conditions in the former test, failure criteria tests and aerosol trapping tests were carried out using low-voltage modules and flange gaskets of an actual plant under severe accident (SA) conditions, without AM. The safety margin for failure temperature of the penetrations and the credit for fission product (FP) aerosol trapping effect along the leakage paths of the degraded penetrations were evaluated in the present tests. Failure temperature of the penetrations ranged from 270 to 300degC for low-voltage modules and 300 to 350degC for flange gaskets under 0.4 to 1.0 MPa conditions. Pressure dependency on failure temperature was small. This means that the safety margin of failure temperature under AM condition is more than 70degC. By introducing a equivalent leak area for the damaged test pieces, total leak area was estimated which was smaller than ...

1999-07-01

5

Grafoil applications on-plant  

International Nuclear Information System (INIS)

Presented in this report are the quantitative and qualitative aspects of the more than 5,800 applications of Grafoil on-plant. The subject all-graphite product was originally made by the Union Carbide Corporation. Its utilization in the forms of valve packing, gasketing and sealant tapes for leak repair and prevention on-plant since March 1970 is marked with typical zero-leak results. For all practical purposes, the successful results with Grafoil implementation indicate an unqualified control of leakage problems that began in 1967 with the V-11 and V-12 valves in the primary system of N Reactor. Meaningfully, the accruals of savings with existing and future applications shall continue to be incalculable in personnel exposure, maintenance, and capital. Inherent in the savings are the devised methodology and innovative developments coordinately employed in resolving the leak repair problems.

6

Friction in ultra-thin conjunction of valve seals of pressurised metered dose inhalers  

British Library Electronic Table of Contents (United Kingdom)

In many drug dispensing devices, such as syringes and inhalers, an elatomeric gasket is used to prevent the formulation from leaking from the chamber. During device actuation, the seal is subjected to friction, which in turn causes its deformation and can cause unintentional leakage, thus dose variability. Additionally, friction of seal is responsible for a host of potential problems such undue effort required for actuation and potential wear. The mechanism of friction generation in the seal conjunction is complex, arising from adhesion of rubber in contact with the moving interface, viscous action of a thin film of fluid and deformation of seal asperities. Therefore, the first step in understanding the conjunctional behaviour of rubber seals is a fundamental study of mechanisms of frictio...

2010-01-01

7

Quaternion quantum mechanics as a true 3+1-dimensional theory of tachyons  

International Nuclear Information System (INIS)

Using a new approach to quaternion mechanics based on De Broglie waves, it is shown that such a theory describes tachyons and that the quantum theory of tachyons should be a quaternionic one. (U.K.).

8

Modeling of spray combustion in Direct-injection diesel engine. Final report, January 1984-December 1987  

Energy Technology Data Exchange (ETDEWEB)

A mathematical model was developed to predict the penetration of a transient fuel spray, the temporal and spatial distribution of air-fuel mixture before the end of ignition delay and the subsequent pressure rise during combustion in a Direct-Injection Diesel Engine with and without swirl. The model accounts for the non-isothermal and non-isobaric character of processes during fuel injection resulting from continuous motion of the piston. The effects of various engine operating variables on spray were studied and graphically presented. The calculated spray penetration with and without crossflow of air is compared with the available experimental data of other researchers with good agreement. The model can predict the rate of combustible-mixture formation, the rate of heat release and cylinder pressure as a function of time in direct injection (DI) diesel engine. A single-cylinder D.I. research diesel engine was operated with N-hexadecane as the engine fuel to validate the mathematical ...

1988-01-30

9

Soluble theory of massless scalar two-dimensional QED  

Energy Technology Data Exchange (ETDEWEB)

In this Brief Report, we analyze a generalized theory of massless scalar QED{sub 2} and show that, unlike the conventional scalar QED{sub 2}, it is free from infrared divergence problems. The model is exactly soluble and may describe, in a (1+1)-dimensional space-time, noninteracting spin-one tachyons. {copyright} {ital 1999} {ital The American Physical Society}

1999-03-01

10

On multitemporal generalization of Newton's gravitational law  

CERN Document Server

A n-time generalization of Newton's law (of universal gravitation) formula in N =n + d + 1-dimensional space-time is conjectured. This formula implies a relation for effective N-dimensional gravitational constant G_{eff} = G cos^2 \\theta, where \\theta is the angle between the direction of motion of two particles in n-dimensional time manifold R^n.

2009-01-01

11

Radiation resistance of flexible graphites  

International Nuclear Information System (INIS)

Polymer sealing parts are widely used in various branches of engineering as detachable joints that operate at normal and cryogenic temperatures. They are also used in nuclear-power engineering to seal pumps, pipelines, etc., where they operate at 600-650 K under a neutron fluence of around 10"1"6 cm"-"2 (E #>=# 0.18 MeV) and concomitant #gamma#-irradiation of about 10"6 R. The fluoroplastic-based materials currently used degrade when irradiated in water at 320-360 K with a neutron fluence of 10"1"5 cm"-"2 (thermal neutrons) or 10"1"4 cm"-"2 (fast neutrons), and a concomitant #gamma#-irradiation dose of 2 x 10"6 R. The strength of these fluoroplastics decreases markedly after #gamma#-irradiation (from a cobalt source) at room temperature at doses above 10"6 R. For this reason, flexible and swelling graphites are finding ever increasing application. Graflex foils made of extra-pure natural graphite were found to be radiation-resistant and suitable for use as seals and planar ...

12

Spatial structure of compound dither in L/H transition  

Energy Technology Data Exchange (ETDEWEB)

To study the plasma evolution and spatial structure at the L/H transition, the double hysteresis is examined by use of the 1-dimensional transport model equations. Three mechanisms for the bipolar losses, i.e., the loss cone loss, collisional bulk viscosity loss of ions and the anomalous loss are simultaneously retained. Five-fold multiple bifurcations are found to exist at the plasma edge, similar to the previous 0-dimensional study. Double hysteresis causes a self-generated oscillation, which is attributed to the compound dither, a kind of ELMs. Spatio-temporal evolution of the compound dither is analyzed. (author)

2000-03-01

13

Tensor network states and geometry  

CERN Document Server

Tensor network states are used to approximate ground states of local Hamiltonians on a lattice in D spatial dimensions. Different types of tensor network states can be seen to generate different geometries. Matrix product states (MPS) in D=1 dimensions, as well as projected entangled pair states (PEPS) in D>1 dimensions, reproduce the D-dimensional physical geometry of the lattice model; in contrast, the multi-scale entanglement renormalization ansatz (MERA) generates a (D+1)-dimensional holographic geometry. Here we focus on homogeneous tensor networks, where all the tensors in the network are copies of the same tensor, and argue that certain structural properties of the resulting many-body states are preconditioned by the geometry of the tensor network and are therefore largely independent of the choice of variational parameters. Indeed, the asymptotic decay of correlations in homogeneous MPS and MERA for D=1 systems is seen to be ...

2011-01-01

14

Smoothing of laser energy deposition by gas jets  

International Nuclear Information System (INIS)

Smoothing of laser beam non-uniformities using gas jets has been studied. The experiment has been performed with the PALS (Prague Asterix Laser System) laser working at 0.44 ?m with an intensity of about 1015 W/cm2. The laser beam has been split in two by a prism thus creating an artificial large-scale non-uniformity (? 90 ?m). We recorded time resolved and static images of laser-gas jet interaction with and without an Al target. Multi 1-dimensional and 2-dimensional simulations show that such interaction acts redistributing the over-intensities over larger surface. This effect has to be attributed to ionization processes with consequent laser beam refraction. Results show that Argon gas jet produces a strong refraction of the laser beam thus strongly reducing the initial two spots separation. (authors)

2009-08-01

15

Linear family of Lie brackets on the space of matrices $Mat(n\\times m,\\K)$ and Ado's Theorem  

CERN Document Server

In this paper we classify a linear family of Lie brackets on the space of rectangular matrices $Mat(n\\times m,\\K)$ and we give an analogue of the Ado's Theorem. We give also a similar classification on the algebra of the square matrices $Mat(n, \\K)$ and as a consequence, we prove that we can't built a faithful representation of the $(2n+1)$-dimensional Heisenberg Lie algebra $\\mathfrak{H}_n$ in a vector space $V$ with $\\dim V\\leq n+1$. Finally, we prove that in the case of the algebra of square matrices $Mat(n,\\K)$, the corresponding Lie algebras structures are a contraction of the canonical Lie algebra $\\mathfrak{gl}(n,\\K)$.

2008-01-01

16

Flavor Superconductivity & Superfluidity  

CERN Document Server

In these lecture notes we derive a generic holographic string theory realization of a p-wave superconductor and superfluid. For this purpose we also review basic D-brane physics, gauge/gravity methods at finite temperature, key concepts of superconductivity and recent progress in distinct realizations of holographic superconductors and superfluids. Then we focus on a D3/D7-brane construction yielding a superconducting or superfluid vector-condensate. The corresponding gauge theory is 3+1-dimensional N=2 supersymmetric Yang-Mills theory with SU(N) color and SU(2) flavor symmetry. It shows a second order phase transition to a phase in which a U(1) subgroup of the SU(2) symmetry is spontaneously broken and typical superconductivity signatures emerge, such as a conductivity (pseudo-)gap and the Meissner-Ochsenfeld effect. Condensates of this nature are comparable to those recently found experimentally in p-wave superconductors such as a ruthenate ...

2010-01-01

17

Emergence of firms in $(d+1)$-dimensional work space  

CERN Document Server

Standard micro-economics concentrate on the description of markets but is seldom interested in production. Several economists discussed the concept of a firm, as opposed to an open labour market where entrepreneurs would recrute workers on the occasion of each business opportunity. Coase \\cite{Coase} is one of them, who explains the existence of firms as institution because they reduce the transaction costs with respect to an open labour market. Whatever the rationale proposed by economists to account for the existence of firms, their perspective is based on efficiency and cost analysis. Little attention is paid to the dynamics of emergence and evolution of firms. The aim of the present manuscript is to check the global dynamical properties of a very simple model based on bounded rationality and reinforcement learning. Workers and managers are localised on a lattice and they choose collaborators on the basis of the success of previous work relations. The choice algorithm is largely ...

2008-01-01

18

A proposition of 3D inertial tolerancing to consider the statistical combination of the location and orientation deviations  

CERN Document Server

Tolerancing of assembly mechanisms is a major interest in the product life cycle. One can distinguish several models with growing complexity, from 1-dimensional (1D) to 3-dimensional (3D) (including form deviations), and two main tolerancing assumptions, the worst case and the statistical hypothesis. This paper presents an approach to 3D statistical tolerancing using a new acceptance criterion. Our approach is based on the 1D inertial acceptance criterion that is extended to 3D and form acceptance. The modal characterisation is used to describe the form deviation of a geometry as the combination of elementary deviations (location, orientation and form). The proposed 3D statistical tolerancing is applied on a simple mechanism with lever arm. It is also compared to the traditional worst-case tolerancing using a tolerance zone.

2010-01-01

19

On cosmological type solutions in multidimensional model with Gauss-Bonnet term  

CERN Document Server

A (n +1)-dimensional Einstein-Gauss-Bonnet (EGB) model is considered. For diagonal cosmological type metrics the equations of motion are reduced to a set of Lagrange equations. The effective Lagrangian contains two minisuperspace metrics on R^n. The first one is the well-known 2-metric of pseudo-Euclidean signature and the second one is the Finslerian 4-metric that is proportional to n-dimensional Berwald-Moor 4-metric. When a synchronous-like time gauge is considered the equations of motion are reduced to an autonomous system of first order differential equations. For the case of the pure Gauss-Bonnet model two exact solutions with power-law and exponential dependence of scale factors (w.r.t. synchronous-like variable) are obtained. In cosmological case the first solution was obtained earlier by A. Toporensky and P. Tretyakov for n = 5 (and verified for n = 6,7). A generalization of the effective Lagrangian to the Lowelock case is conjectured. ...

2009-01-01

20

Analysis of enclosed sodium pool fire scenario in sodium fire experimental facility  

International Nuclear Information System (INIS)

Liquid sodium is used as coolant in Fast Breeder Reactors (FBR). There is a likelyhood of sodium spillage in ambient air in the Steam Generator Building (SGB) of the FBR plant. Due to high chemical reactivity with oxygen, especially at temperatures greater than 573 K, it catches fire very easily. In order to carryout safety related experimental studies for different modes of sodium fires and to develop suitable mathematical models for the assessment of their consequences, an experimental facility (SFEF, Sodium Fire Experimental Facility) is being setup a IGCAR, Kalpakkam. The SFEF is having a 540 m"3 volume experimental hall. Stainless steel linear will be provided on the inside surfaces of experimental hall walls, ceiling and floor. Analysis has been carried out for enclosed sodium pool fire scenarios in SFEF by using sodium pool fire code SOFIRE II, which estimates the thermal transients like pressure rise, gas temperature rise, cell wall temperature rise and sodium burning rate. ...

2007-04-22

 
 
 
 
21

Application of the porous media model for the LWR process components  

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: A porous media solution PORFLO has been developed for the 3-dimensional two-phase flow by describing the process facility in Cartesian or cylindrical coordinates. The local porosity fraction is applied for distinguishing the fluid filled volumes from the solid structures. The solid structure contribute the two-phase flow through the wall friction, flow area and heat transfer. Optionally the solid structure may contain primary liquid of steam generators, steam in the higher temperature and pressure to be condensed or electrical heating power. By using these optional boundary conditions three different process facilities have been analysed. The thermohydraulic solution based on 5-equation approach, where the conservation equations are solved for the liquid and gas (vapour) mass, mixture momentum (giving the velocity only for the mixture), liquid and gas energy, is described shortly. In addition to that the principles modelling optional boundary ...

2005-07-01

22

Scale-up of two-phase flow in heterogeneous chalk. Matrix properties  

Energy Technology Data Exchange (ETDEWEB)

This investigation presents scale-up of a detailed heterogeneous geostatistical model to a full field reservoir simulation model, considering both single and two-phase flow properties. The model represents a typical low permeability Danish North Sea chalk reservoir and includes capillary pressure and saturation end-point variations. Two new up-scaling methods has been investigated, all based on fine scale simulation on a cross section of the geomodel. The first methods assumes piston style behaviour and a coupled viscosity is introduced into the basic Darcy`s equations. The second method is a modification of the JBN method traditionally applied in analysing results from core flooding experiments, which emerged as the most successful and therefore also the recommended method. 1. In addition to the up scaling work we review the Equivalent Radius Method for capillary pressure normalisation with explicit derivation of type functions for Maastrichtian and Danian chalk types. Implementation ...

1998-02-01