Nondestructive testing of brazed rocket engine components

Report details study made of nondestructive radiographic, ultrasonic, thermographic, and leak test methods used to inspect and evaluate the quality of the various brazed joints in liquid-propellant rocket engine components and assemblies. Descriptions of some of the unique equipment and methods developed are included

Parameters for Twisted Representations

The study of Hermitian forms on a real reductive group $G$ gives rise, in the unequal rank case, to a new class of Kazhdan-Lusztig-Vogan polynomials. These are associated with an outer automorphism $\delta$ of $G$, and are related to representations of the extended group $$. These polynomials were defined geometrically by Lusztig and Vogan in "Quasisplit Hecke Algebras and Symmetric Spaces", Duke Math. J. 163 (2014), 983--1034. In order to use their results to compute the polynomials, one needs to describe explicitly the extension of representations to the extended group. This paper analyzes these extensions, and thereby gives a complete algorithm for computing the polynomials. This algorithm is being implemented in the Atlas of Lie Groups and Representations software

The energy dependence of p_t angular correlations inferred from mean-p_t fluctuation scale dependence in heavy ion collisions at the SPS and RHIC

We present the first study of the energy dependence of pt angular correlations inferred from event-wisemean transverse momentum (pt) fluctuations in heavy ion collisions. We compare our large-acceptancemeasurements at CM energies √^sNN = 19.6, 62.4, 130 and 200 GeV to SPS measurements at 12.3 and 17.3 GeV. p_t angular correlation structure suggests that the principal source of p_t correlations and fluctuations is minijets (minimum-bias parton fragments). We observe a dramatic increase in correlations and fluctuations from SPS to RHIC energies, increasing linearly with ln √^sNN from the onset of observable jet-related (p_t) fluctuations near 10 GeV

High torque bellows seal rotary drive

Bellows seal rotary drive device was developed which allows high torque transmission through sealed compartments. Bearing friction which would normally be carried by sealing bellows in comparable devices is absorbed by universal-gimbal joint. It can be used to transmit high torque, low speed, rotary motion through sealed barriers to prevent contamination or escape of fluids

Results on the nucleon spin structure

SMC performed an investigation of the spin structure of the nucleon by measuring deep inelastic scattering of polarised muons off polarised protons and deuterons. A summary of the results for spin structure functions and sum rules is given.Comment: 8 pages, LaTeX, Talk given at the Workshop on "Symmetry and Spin - PRAHA98", Prag, September 1998. Proceedings to be published by Czech. Journ. Phy

Delamination micromechanics analysis

A three-dimensional finite element analysis was developed which includes elastoplastic, orthotropic material response, and fracture initiation and propagation. Energy absorption due to physical failure processes characteristic of the heterogeneous and anisotropic nature of composite materials is modeled. A local energy release rate in the presence of plasticity was defined and used as a criterion to predict the onset and growth of cracks in both micromechanics and macromechanics analyses. This crack growth simulation technique is based upon a virtual crack extension method. A three-dimensional finite element micromechanics model is used to study the effects of broken fibers, cracked matrix and fiber-matrix debond on the fracture toughness of the unidirectional composite. The energy release rates at the onset of unstable crack growth in the micromechanics analyses are used as critical energy release rates in the macromechanics analysis. This integrated micromechanical and macromechanical fracture criterion is shown to be very effective in predicting the onset and growth of cracks in general multilayered composite laminates by applying the criterion to a single-edge notched graphite/epoxy laminate subjected to implane tension normal to the notch

A non-monotonic constitutive model is not necessary to obtain shear banding phenomena in entangled polymer solutions

In 1975 Doi and Edwards predicted that entangled polymer melts and solutions can have a constitutive instability, signified by a decreasing stress for shear rates greater than the inverse of the reptation time. Experiments did not support this, and more sophisticated theories incorporated Marrucci's idea (1996) of removing constraints by advection; this produced a monotonically increasing stress and thus stable constitutive behavior. Recent experiments have suggested that entangled polymer solutions may possess a constitutive instability after all, and have led some workers to question the validity of existing constitutive models. In this Letter we use a simple modern constitutive model for entangled polymers, the non-stretching Rolie-Poly model with an added solvent viscosity, and show that (1) instability and shear banding is captured within this simple class of models; (2) shear banding phenomena is observable for weakly stable fluids in flow geometries that impose a sufficiently inhomogeneous total shear stress; (3) transient phenomena can possess inhomogeneities that resemble shear banding, even for weakly stable fluids. Many of these results are model-independent.Comment: 5 figure

Activation of Long Descending Propriospinal Neurons in Cat Spinal Cord

Isolated mammalian spinal cord has been shown capable of generating locomotor activity. Propriospinal systems assumed to coordinate fore- and hindlimb activity are poorly understood. This study characterizes the long descending propriospinal (LDP) neurons in terms of the location of the somas and their peripheral inputs by direct neuronal recording. Anatomical studies using axonal retrograde transport of horseradish peroxidase from the lumbar to the cervical spinal cord as a tracer first described these neurons. Two hundred and thirty-one LDP neurons were identified in electrophysiological experiments. Of these, 123 responded to natural stimulation, and about 50% of the others were activated only by electrical stimulation. The majority of cells were located in laminae VII and VIII in agreement with anatomical data. The most effective stimuli were mechanical stimulation of skin, deep pressure to subcutaneous tissues, and paw joint movement. Bot excitatory and inhibitory responses were observed

Saturn S-IB stage Final static test report, stage S-IB-4

Acceptance static test firing data for Saturn flight stage S-IB-

Are there socioeconomic gradients in stage and grade of breast cancer at diagnosis? Cross sectional analysis of UK cancer registry data

Socioeconomic gradients in uptake of breast cancer screening in the United Kingdom should, intuitively, lead to socioeconomic gradients in disease progression at diagnosis. However, studies have found little evidence of such an effect. Although this could be interpreted as evidence that socioeconomic gradients in uptake of screening do not have clinically important consequences, all of the published studies have used data from before (pre-1988) or during the early stages (1988-95) of implementation of the national breast cancer screening programme. We investigated the relation between socioeconomic position and progression of breast cancer at diagnosis by using recent data from the Northern and Yorkshire Cancer Registry and Information Service (NYCRIS), which is estimated to achieve around 93% ascertainment