The quadratic function approaching method (QFAM) is introduced for magnetotelluric sounding (MT) data inversion. The method takes the advantage of that quadratic function has single extreme value, which avoids leading to an inversion solution for local minimum and ensures the solution for global minimization of an objective function. The method does not need calculation of sensitivity matrix and not require a strict initial earth model. Examples for synthetic data and field measurement data indicate that the proposed inversion method is effective.

Version 3 of the Hadley Centre Atmospheric Model (HadAM3) has been used to demonstrate one means of comparing a general circulation model with observations for a specific climate perturbation, namely the strong 1997/98 El Nino. This event was characterized by the collapse of the tropical Pacific's Walker circulation, caused by the lack of a zonal sea surface temperature gradient during the El Nino. Relative to normal years, cloud altitudes were lower in the western portion of the Pacific and higher in the eastern portion. HadAM3 likewise produced the observed collapse of the Walker circulation, and it did a reasonable job of reproducing the west/east cloud structure changes. This illustrates that the 1997/98 El Nino serves as a useful means of testing cloud-climate interactions in climate models.

BNL is responsible for the design and construction of the US Spallation Neutron Source (SNS) accumulator ring. Titanium Nitride (TiN) coating on the stainless steel vacuum chamber of the SNS accumulator ring is needed to reduce the secondary electron yield (SEY) and the undesirable resonant multiplication of electrons. The total SEY of TiN coated stainless steel material has been measured after coating samples were exposed to air and after electron and ion bombardment. We report here about TiN coating system setup at BNL and SEY measurements results at CERN, SLAC and KEK. We also present some simulation results of SNS accumulator ring electron-cloud effects using different SEY values.

High-resolution surveillance imaging with apertures greater than a few inches over horizontal or slant paths at optical or infrared wavelengths will typically be limited by atmospheric aberrations. With static targets and static platforms, we have previously demonstrated near-diffraction limited imaging of various targets including personnel and vehicles over horizontal and slant paths ranging from less than a kilometer to many tens of kilometers using adaptations to bispectral speckle imaging techniques. Nominally, these image processing methods require the target to be static with respect to its background during the data acquisition since multiple frames are required. To obtain a sufficient number of frames and also to allow the atmosphere to decorrelate between frames, data acquisition times on the order of one second are needed. Modifications to the original imaging algorithm will be needed to deal with situations where there is relative target to background motion. In this paper, we present an extension of these imaging techniques to accommodate mobile platforms and moving targets.

The luminosity of the Relativistic Heavy Ion Collider has improved significantly [1] over the first three physics runs. A number of special rf techniques have been developed to facilitate higher luminosity. The techniques described herein include: an ultra low-noise rf source for the 197 MHz storage rf system, a frequency shift switch-on technique for transferring bunches from the acceleration to the storage system, synchronizing the rings during the energy ramp (including crossing the transition energy) to avoid incidental collisions, installation of dedicated 200 MHZ cavities to provide longitudinal Landau damping on the ramp, and the development of a bunch merging scheme in the Booster to increase the available bunch intensity from the injectors.

The Relativistic Heavy Ion Collider (RHIC) requires a low noise rf source to ensure that beam lifetime during a store is not limited by the rf system. The beam is particularly sensitive to noise from power line harmonics. Additionally, the rf source must be flexible enough to handle the frequency jump required for rebucketing (transferring bunches from the acceleration to the storage rf systems). This paper will describe the design of a Direct Digital Synthesizer (DDS) based system that provides both the noise performance and the flexibility required.

We present within this paper a series of experiments, which yield new observations to further our understanding of the transient collisional x-ray laser medium. We use the recently developed technique of picosecond x-ray laser interferometry to probe the plasma conditions in which the x-ray laser is generated and propagates. This yields two dimensional electron density maps of the plasma taken at different times relative to the peak of the 600ps plasma-forming beam. In another experimental campaign, the output of the x-ray laser plasma column is imaged with a spherical multilayer mirror onto a CCD camera to give a two-dimensional intensity map of the x-ray laser output. Near-field imaging gives insights into refraction, output intensity and spatial mode structure. Combining these images with the density maps gives an indication of the electron density at which the x-ray laser is being emitted at (yielding insights into the effect of density gradients on beam propagation). Experimental observations coupled with simulations predict that most effective coupling of laser pump energy occurs when the duration of the main heating pulse is comparable to the gain lifetime ({approx}10ps for Ni-like schemes). This can increase the output intensity by more than an order of magnitude relative to …

Alloy 22 (UNS N06022) is the candidate material for the corrosion resistant, outer barrier of the Yucca Mountain nuclear waste containers. One of the potential corrosion degradation modes of the container is uniform or passive corrosion. Therefore it is of importance to understand the stability of the oxide film, which will control the passive corrosion rate of Alloy 22. Many variables such as temperature, composition and pH of the electrolyte, applied potential, and microstructure and composition of the base metal would determine the thickness and composition of the oxide film. The purpose of this research work was to use electrochemical and surface analysis techniques to explore the influence of solution pH and applied potential on the characteristics of the oxide film formed on Alloy 22 and two experimental alloys containing differing amounts of chromium (Cr) and molybdenum (Mo). Results confirm that bulk metal composition is fundamental to the passive behavior and potential breakdown of the studied alloys. In these preliminary results, welded and non-welded Alloy 22 did not show differences in their anodic behavior.

A study was conducted to assess the ability of phased-array ultrasonic techniques to detect and accurately determine the size of flaws from the far-side of wrought austenitic piping welds. Far-side inspections of these welds are currently performed on a “best effort” basis and do not conform to ASME Code Section XI Appendix VIII performance demonstration requirements. For this study, four circumferential welds in 610mm diameter, 36mm thick ASTM A-358, Grade 304 vintage austenitic stainless steel pipe were examined. The welds were fabricated with varied welding parameters; both horizontal and vertical pipe orientations were used, with air and water backing, to simulate field welding conditions. A series of saw cuts, electro-discharge machined (EDM) notches, and implanted fatigue cracks were placed into the heat affected zones of the welds. The saw cuts and notches range in depth from 7.5% to 28.4% through-wall. The implanted cracks ranged in depth from 5% through wall to 64% through wall. The welds were examined with two phased-array probes, a 2.0 MHz transmit-receive longitudinal wave array and a 2.0 MHz transmit-receive shear wave array. These examinations showed that both phased-array transducers were able to detect and accurately length-size, but not depth size, all of the notches and …

The importance of a Super-B Factory in the search for New Physics, in particular, due to CP-od phase(s) from physics beyond the Standard Model is surveyed. The first point to emphasize is that we know now how to directly measure all three angles of the unitarity triangle very cleanly, i. e. without theoretical assumptions with irreducible theory error {le} 1%; however this requires much more luminosity than is currently available at B-factories. Direct searches via penguin-dominated hadronic modes as well as radiative, pair-leptonic and semi-leptonic decays are also discussed. Null tests of the SM are stressed as these will play a crucial role especially if the effects of BSM phase(s) on B-physics are small.

A practical obstacle for stochastic cooling in high-energy colliders like RHIC is the large amount of power needed for the cooling system. Based on the coasting-beam Fokker-Planck (F-P) equation, we analytically derived the optimum cooling rate and cooling power for a beam of uniform distribution and a cooling system of linear gain function. The results indicate that the usual back-of-envelope formula over-estimated the cooling power by a factor of the mixing factor M. On the other hand, the scaling laws derived from the coasting-beam Fokker-Planck approach agree with those derived from the bunched-beam Fokker-Planck approach if the peak beam intensity is used as the effective coasting-beam intensity. A longitudinal stochastic cooling system of 4-8 GHz bandwidth in RHIC can effectively counteract intrabeam scattering, preventing the beam from escaping the RF bucket becoming debunched around the ring.

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

Dimensional changes related to temperature cycling of the beta and delta polymorphs of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) are important for a variety of applications. The coefficient of thermal expansion (CTE) of the beta and delta phases are measured and reported in this work over a temperature range of -20 C to 215 C. In addition, dimensional changes associated with the phase transition were measured, both through the transition and back down. Initially, differential scanning calorimetry (DSC) was used to investigate back conversion of the delta phase to the beta phase polymorph. The most successful approach was first to measure the amount of the beta to delta conversion, then after a given cooling period a repeat analysis, to measure the heat consumed by a second pass through the beta to delta phase transition. In addition, TMA is used to measure the dimensional change of a 0.20-gram sample of HMX during its initial heating and then three days later during a 2nd heating. This HMX shows the beta to delta phase transition a second time, thereby confirming the back conversion from delta to beta phase HMX.

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Optimizing compilers have a long history of applying loop transformations to C and Fortran scientific applications. However, such optimizations are rare in compilers for object-oriented languages such as C++ or Java, where loops operating on user-defined types are left unoptimized due to their unknown semantics. Our goal is to reduce the performance penalty of using high-level object-oriented abstractions. We propose an approach that allows the explicit communication between programmers and compilers. We have extended the traditional Fortran loop optimizations with an open interface. Through this interface, we have developed techniques to automatically recognize and optimize user-defined array abstractions. In addition, we have developed an adapted constant-propagation algorithm to automatically propagate properties of abstractions. We have implemented these techniques in a C++ source-to-source translator and have applied them to optimize several kernels written using an array-class library. Our experimental results show that using our approach, applications using high-level abstractions can achieve comparable, and in cases superior, performance to that achieved by efficient low-level hand-written codes.

In this paper we discuss, and study the feasibility of a method that may be used to measure the focusing properties of a magnet. This method may prove valuable when applied to ''non-conventional'' magnets that deviate from the usual dipole magnets or other multipole magnets (quadrupoles/sextupoles etc.) which are commonly used in a synchrotron or a beam line. In this category of ''non-conventional'' magnets, fall special magnets, which come under the name ''Snakes'', which are being used in synchrotron accelerators to introduce artificial spin resonances to help overcome the intrinsic and/or imperfection spin resonances which appear during the acceleration of polarized beams. This method of measuring the focusing properties of a magnet requires the use of ''low energy'' and ''high rigidity'' heavy-ions which may be obtained from the BNL Tandem accelerator. In brief the method consists on, injecting ''narrow-beamlets'' of heavy ions into a magnet and measuring the coordinates, of these ''narrow-beamlets'', at the entrance and exit of the magnet. From the measurement of the coordinates of the ''narrow-beamlets'' we can deduce information on the R matrix (first order transfer matrix elements) and higher order matrix elements that define the focusing properties of the magnet.

The phase diagrams of Ce, Th, and Pu metals have been studied by means of density-functional theory (DFT). In addition to these metals, the phase stability of Ce-Th and Pu-Am alloys has been also investigated from first-principles calculations. Equation-of-state (EOS) for Ce, Th, and the Ce-Th alloys has been calculated up to 1 Mbar pressure in good comparison to experimental data. Present calculations shows that the Ce-Th alloys adopt a body-centeredtetragonal (bct) structure upon hydrostatic compression that is in excellent agreement with measurements. The ambient pressure phase diagram of Pu is shown to be very poorly described by traditional DFT but rather well modeled when including magnetic interactions. In particular, the anomalous {var_sigma} phase of Pu is shown to be stabilized by magnetic disorder at elevated temperatures. The Pu-Am system has also been studied in a similar fashion and it is shown that this system, for about 25% Am content, becomes antiferromagnetic below about 400 K that corroborate the recent discovery of a Curie-Weiss behavior in this system.

Fracture mechanics methodologies for flaw stability analysis of a storage tank were compared in terms of the maximum stable through-wall flaw sizes or ''instability lengths.'' The comparison was made at a full range of stress loading at a specific set of mechanical properties of A285 carbon steel and with the actual tank configuration. The two general methodologies, the J-integral-tearing modulus (J-T) and the failure assessment diagram (FAD), and their specific estimation schemes were evaluated. A finite element analysis of a flawed tank was also performed for validating the J estimation scheme with curvature correction and for constructing the finite element-based FAD. The calculated instability crack lengths show that the J-T methodology that uses an estimated scheme, and the material-specific FAD, most closely approximate the result calculated with finite element analysis for the stress range that bounds those expected at the highest fill levels in the storage tanks. The results from the other FAD methods show instability lengths less than the J-T results over this range.

The new Isotope Production Facility (IPF) at Los Alamos National Laboratory has been commissioned during the spring of 2004. Commissioning activities focused on the establishment of a radionuclide database, the review and approval of two specific target stack designs, and four trial irradiation runs with subsequent chemical processing and data analyses. This paper highlights some aspects of the facility and the targetry of the two approved target stacks used during the commissioning process.

We investigate performance characteristics for the LU factorization of large matrices with various sparsity patterns. We consider supernodal right-looking parallel factorization on a bi-dimensional grid of processors, making use of static pivoting. We develop a performance model and we validate it using the implementation in SuperLU-DIST, the real matrices and the IBM Power3 machine at NERSC. We use this model to obtain performance bounds on parallel computers, to perform scalability analysis and to identify performance bottlenecks. We also discuss the role of load balance and data distribution in this approach.

The radiation effects on the physical characteristic of the sewage sludge were studied in order to obtain information which will be used for study on the enhancement of the sludge's dewaterability. Water contents, capillary suction time, zeta potential, irradiation dose, sludge acidity, total solid concentration, sludge particle size and microbiology before and after irradiation were investigated. Irradiation gave an effect on physical characteristics sludge. Water content in sludge cake could be reduced by irradiation at the dose of 10kGy.

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The purpose of this work is to settle a laboratory for Iridium -192 sources production, that is, to determine a wire activation method and to build a hot cell for the wires manipulation, quality control and packaging. The paper relates, mainly, the wire activation method and its quality control. The wire activation is carried out in our nuclear reactor, IEA- R1m.

Typically, large scientific datasets (order of terabytes) are generated at large computational centers, and stored on mass storage systems. However, large subsets of the data need to be moved to facilities available to application scientists for analysis. File replication of thousands of files is a tedious, error prone, but extremely important task in scientific applications. The automation of the file replication task requires automatic space acquisition and reuse, and monitoring the progress of staging thousands of files from the source mass storage system, transferring them over the network, archiving them at the target mass storage system or disk systems, and recovering from transient system failures. We have developed a robust replication system, called DataMover, which is now in regular use in High-Energy-Physics and Climate modeling experiments. Only a single command is necessary to request multi-file replication or the replication of an entire directory. A web-based tool was developed to dynamically monitor the progress of the multi-file replication process.