Energy Technology Data Exchange (ETDEWEB)

The Thomsen and Frandsen (1983) cosmological test employing the observed correlation between elliptical galaxy surface brightness and scale size in order to avoid problems due to dynamical evolution is presently extended to make use of arbitrary galaxy samples. The explicit dependence on stellar evolution is also demonstrated. On the assumption that this evolution is calculable, an equation for the deceleration parameter entirely in terms of observables is derived. The test is applied to two available samples. 25 references.

International Nuclear Information System (INIS)

The equivalent doses of K-feldspar grains in a range of grain sizes from 90 to 250#mu#m diameter were measured using a single-aliquot regenerative-dose protocol for the infrared stimulated luminescence (IRSL) signals for two samples of desert sand. The equivalent doses for each sample were compared with that for the 125-150#mu#m grains of quartz from the same samples. The results suggested that the K-feldspar equivalent doses were underestimated because of anomalous fading. Measurements of the decay of the IRSL signals following laboratory irradiation for these two samples, and an additional one from a previously published isochron study, showed anomalous fading during the period of laboratory storage. The decay rate was about 3% per decade for all samples and was independent of the grain size used. Using plots of equivalent doses for ...

Science.gov (United States)

The critical currents of A-15 phase Nb(,3)Sn, V(,3)Si, Nb(,3)Ge, V(,3)Ga, and Nb-Sn with a few at.% Ga and Al(,2)O(,3) have been measured at temperatures up to T(,c) and in magnetic fields up to 8T to study fundamental flux pinning interactions as a function of defect size and density. The samples are electron beam evaporated films typically 2 (mu)m thick. Their particular usefulness for this study is that they span the clean to dirty limits and their normal state resistivity and grain size can be controlled by deposition parameters. The grain boundaries are the defects most responsible for flux pinning. The electron scattering mechanism is based on the local change in the coherence length due to increased conduction electron scattering and is chosen from among several possible mechanisms to calculate the elementary pinning force at a grain boundary. A direct summation of the elementary pinning force of ...

Science.gov (United States)

Removal Sampling is an easy-to-use Windows program which calculates population statistics from removal trapping experiment data. Using maximum likelihood methods it ... ...

Energy Technology Data Exchange (ETDEWEB)

Formation of particles from heavy duty diesel and CNG vehicles was studied in laboratory conditions. PM, nano and soot mode particle emissions formed from buses of Euro 2-5 -emission levels were studied in relation to age and type approval characteristics of the vehicle. Characteristic particle emission factors from city driving were obtained by driving the buses on VTT's heavy duty chassis dynamometer applying the transient Braunschweig city cycle. The vehicles were a representative set of Euro 2 to 3 emission categories, supplemented with Euro 4-5 (EEV) -targeted CRT, CNG and DPF cars. Particle number emissions from Euro 4 to 5 buses were 1/100-1/1000 and mass emissions 1/10-1/100 of those of the current fleet. Particle emission from natural gas buses and after an advanced CRT trap contained almost entirely liquid < 60 nm nano particles, which will make filter mass based PM control very challenging in the near future. One result was that gravimetric PM emission could ...

Energy Technology Data Exchange (ETDEWEB)

The bullet evidence in the JFK assassination investigation was reexamined from metallurgical and statistical standpoints. The questioned specimens are comprised of soft lead, possibly from full-metal-jacketed Mannlicher-Carcano, 6.5-mm ammunition. During lead refining, contaminant elements are removed to specified levels for a desired alloy or composition. Microsegregation of trace and minor elements during lead casting and processing can account for the experimental variabilities measured in various evidentiary and comparison samples by laboratory analysts. Thus, elevated concentrations of antimony and copper at crystallographic grain boundaries, the widely varying sizes of grains in Mannlicher-Carcano bullet lead, and the 5-60 mg bullet samples analyzed for assassination intelligence effectively resulted in operational sampling error for the analyses. This deficiency was not considered in the original ...

Energy Technology Data Exchange (ETDEWEB)

Recently, the precise isotope ratios of some refractory elements in meteorites have been reported using inductively coupled plasma mass spectrometry. The in situ decay of {sup 182}Hf (T{sub 1/2}=9 Myr), which was produced at the latest nucleosynthesis, is recognized in many meteorites as isotopic anomalies of its daughter isotope, {sup 182}W. The degrees of relative {sup 182}W isotopic deviation in extra-terrestrial and terrestrial silicate samples vary from +0.3% to {+-}0% related to the size of their parent bodies. One ready interpretation of its correlation is the difference in timing of metal-silicate separation in the parent bodies. Between the earth and meteorite parent bodies, the difference is calculated to be about four times of the half-life of {sup 182}Hf, equivalent to 36 Myr. (author)

International Nuclear Information System (INIS)

The Si_3N_4-rich corner of the phase diagrams for neodymia and ytterbia containing sialons has been investigated by a systematic variation of the m and n values for compositions between 0.5 and 2.0 with a step size of 0.5. Samples requiring nitrides of the rare earth elements have not been prepared. Sintering has been performed at 1800 C for one hour in a nitrogen atmosphere of 1 MPa. The sintered samples were characterized by X-ray diffraction analysis to identify the crystalline phases in equilibrium with sialon. #alpha#- and #beta#-sialon, the 21R AlN polytypoid, and N-melilite M' were found in the Nd containing system. Materials with Yb showed the formation of #alpha#- and #beta#-sialon, and the AlN polytypoids 12H and 21R. The m and n values of the #alpha#-sialon phase have been calculated via their lattice parameters that were refined by a least squares routine. The occurrence and composition of ...

UK PubMed Central (United Kingdom)

The procedure currently used for isolating legionellae from environmental samples recommend filtration through a 0.2-microns-pore-size polycarbonate filter. In this study we evaluated the performance...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Often, lifetime data come from experiments where failure times are grouped. The Weibull distribution is a popular distribution for modeling failure times. Maximum likelihood estimation (MLE) has outstanding large sample properties for the Weibull distribution. This article evaluates small sample properties of MLEs for grouped data. We evaluate sample size requirements for MLE asymptotic properties to take effect. We compare type I and type II censoring for pooled experiments and conclude that bias for the shape parameter estimate can be alarmingly high especially for type II censored data. Finally, we investigate the benefits of the pooled analysis.

Energy Technology Data Exchange (ETDEWEB)

We report a study of the nonmetal-metal transition of free-standing Pd{sub N} clusters (2{<=}N{<=}21) carried out through two different theoretical approaches that are extensively employed in electronic structure calculations: a semi-empirical tight-binding (TB) model and an ab initio DFT pseudopotential model. The calculated critical size for the metallic transition decreases rapidly with the temperature and an oscillatory dependence with the cluster size is obtained, particularly in the DFT approach. The TB model describes the metallic behavior for cluster sizes beyond N{approx}12 well. Our obtained critical size at room temperature is of the order of the experimental estimation.

Energy Technology Data Exchange (ETDEWEB)

Understanding the mechanical properties of biomedical devices is critical in predicting and preventing their failure in the body. Such knowledge is essential, for example, in the design of biomedical stents, which must undergo repeated strain over their ten year lifetimes without breaking. Computational models are used to predict mechanical response of a device, but these models are not complete; there are significant deviations from the predictions, especially when devices are subjected to repeated multi-axial loads. Improving these models requires comparisons with actual measurements of strained nitinol. Local measurements of the full strain tensor can be made using X-ray diffraction techniques, but they are currently limited to materials whose grain size is larger than the X-ray beam size or require several diffraction patterns produced by rotation of the sample. Nitinol stents are nanocrystalline, with grains smaller ...

British Library Electronic Table of Contents (United Kingdom)

Surveillance of a population, such as a weapon stockpile, is needed to discover manufacturing defects as well as deterioration as the population ages. This article considers the risks of sampling rates for surveillance from three perspectives: detection probability of defects in a proportion of a population with pass/fail data, detection of a trend in a defective proportion of the population with pass/fail data, and detection of a trend with quantitative degradation measurements. Understanding of these risks will help the decision maker choose a sampling rate to protect against such problems of a specified size at a tolerable risk.

International Nuclear Information System (INIS)

As part of the 1999 NARSTO Northeast Oxidant and Particulate Study (NE-OPS) field campaign, the DOE G-1 aircraft sampled trace gases and aerosols in and around the Philadelphia metropolitan area. Twenty research flights were conducted between July 25 and August 11. The overall goals of these flights were to obtain a mechanistic understanding of O(sub 3) production; to characterize the spatial and temporal behavior of photo-oxidants and aerosols; and to study the evolution of aerosol size distributions, including the process of new particle formation. Within the NE-OPS program, other groups provided additional trace gas, aerosol, and meteorological observations using aircraft, balloon, remote sensing, and surface based instruments (Phillbrick et al., 2000). In this article we provide an overview of the G-1 observations related to O(sub 3) production, focusing on the vertical distribution of pollutants. Ozone production rates are ...

Energy Technology Data Exchange (ETDEWEB)

A field survey on cadmium, lead, copper, and zinc was performed in Semarang, the fifth largest city in Indonesia. Water, sediment, and fish samples were collected from 101 grids of 2 x 2 km. The objectives of the study were (1) to identify the spatial distribution of metals in the sediments of the greater Semarang area, (2) to estimate the background concentrations of the metals present in Semarang, (3) to provide a simple tool for deriving standards for metals in the sediment, and (4) to explore the potential use of the guppy (Lebistes reticulatus) as a bioindicator of urban metal pollution. To map the spatial distribution of the metals, concentrations of each metal in sediment were plotted against the corresponding city coordinate. On the basis of these plots, background concentrations of the metals were estimated. A combined pollution index can be derived thereafter by calculating the difference between metals concentrations from a ...

Energy Technology Data Exchange (ETDEWEB)

LiFePO{sub 4} cathode materials with distinct particle sizes were prepared by a planetary ball-milling method. The effects of particle size on the morphology, thermal stability and electrochemical performance of LiFePO{sub 4} cathode materials were investigated. The ball-milling method decreased particle size, thereby reducing the length of diffusion and improving the reversibility of the lithium ion intercalation/deintercalation. It is worth noting that the small particle sample prepared using malonic acid as a carbon source achieved a high capacity of 161 mAh g{sup -1} at a 0.1 C rate and had a very flat capacity curve during the early 50 cycles. However, the big particle samples ({proportional_to}400 nm) decayed more dramatically in capacity than the small particle size samples ({proportional_to}200 nm) at high current densities. The ...

British Library Electronic Table of Contents (United Kingdom)

Vignon, M. (2011) Inference in morphological taxonomy using collinear data and small sample sizes: Monogenean sclerites (Platyhelminthes) as a case study. -Zoologica Scripta, 40, 306-316. Taxonomists and evolutionary biologists frequently use a combination of morphological measurements to distinguish between species and investigate local adaptation. However, the entire set of characters often displays various degrees of collinearity. This paper discusses the effect of using collinear data in morphological taxonomy and ways to handle multicollinearity in a classification context, with special consideration for small sample size. In addition, I propose a robust and easy-to-use combination of dimension reduction using partial least squares (PLS) with traditional discriminant methods for morph...

Energy Technology Data Exchange (ETDEWEB)

An updated TRAC 80% large-break loss-of-coolant accident (LBLOCA) has been calculated for the Westinghouse AP600 advanced reactor design, The updated calculation incorporates major code error corrections, model corrections, and plant design changes. The 80% break size was calculated by Westinghouse to be the most severe large-break size for the AP600 design. The LBLOCA transient was calculated to 144 s. Peak cladding temperatures (PCTS) were well below the Appendix K limit of 1,478 K (2,200 F), but very near the cladding oxidation temperature of 1,200 K (1,700 F). Transient event times and PCT for the TRAC calculation were in reasonable agreement with those calculated by Westinghouse using their {und W}COBRA/TRAC code. However, there were significant differences in the detailed phenomena calculated ...

International Nuclear Information System (INIS)

Bench Scale methane cracking tests have been completed using a stack of ten whole SAES(R) St909 pellets - a 6 gram sample size. Methane was found to be the most difficult impurity to process and can impact diffuser operation.

Science.gov (United States)

Carbon steel, copper, zinc and aluminium samples were exposed in different sizes with known ambient parameters in Gran Canaria Island and atmospheric corrosion was investigated. Weight-loss measurements used to determine corrosion damage were complemented...

Science.gov (United States)

...visible damage. (k) Corrosion resistance. Each metal part of a...evidence of salt-spray corrosion resistance equal to or greater than...sample of test metal must show corrosion resistance equal to or better than...

International Nuclear Information System (INIS)

This paper presents the effect of precursor powder size on the thermoelectric properties of sintered nanostructured bulk materials. The transport properties of the nanostructured bulk show a dramatic size effect. There are a lower thermal and electrical conductivity for the bulk with smaller nanopowders. The dimensionless figure-of merit values (ZT) of almost all the samples are much lower than those of the list reported data in the paper because the decrease in the thermal conductivity is counteracted by the reduction in the electrical conductivity and the Seebeck coefficient. The combination route of hydro/solvothermal synthesis and spark-plasma-sintering method provide a well controlled way to significantly reduce the thermal conductivity.

International Nuclear Information System (INIS)

In 16 female patients wick colpourethrocystography was performed directly successively with large-size films as well as medium-size films (intensifier fluorography). The area exposure products were measured by a dosemeter closely attached to the diaphragm and separately for radiography and fluorography, resp. Surface doses as well as organ doses were calculated according to Rosenstein. The average radiatin doses of the active bone marrow were 6.03 mGy for examination with large-size films and 1.27 mGy for fluorography; the average gonadal doses were 7.45 mGy and 1.56 mGy, resp. The portion of fluoroscopy in radiation exposure amounted to 14.8% in large-size film examination, but was 74.0% in medium-size examination. Thus the comparative results revealed a significant reduction of the patient's radiation dose by application of intensifier fluorography in ...

Energy Technology Data Exchange (ETDEWEB)

CuO/bentonite and CuO-BHA nanocomposites were studied as oxygen carriers in chemical-looping combustion (CLC) of simulated synthesis gas. Global reaction rates of reduction and oxidation, as the function of reaction conversion, were calculated from 10-cycle oxidation/reduction tests utilizing thermogravimetric analysis at atmospheric pressure between 700 and 900{degree}C. It was found that the reduction reactions are always faster than oxidation reactions; reaction temperature and particle size do not significantly affect the reaction performance of CuO/bentonite. Multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for production of CO{sub 2} from fuel gas at 800 and 900{degree}C and full consumption of hydrogen during the reaction. Results of the tapered element oscillating microbalance showed a negative effect of pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. ...

Energy Technology Data Exchange (ETDEWEB)

Molecular dynamics computer simulations of a dense nanocrystalline Nickel sample are performed on the parallel Cray T3 (EPFL-Lausanne). The sample contains 50 grains with an average size of 3 nm. By perturbing the relaxed configuration elastic and plastic properties are studied. (author) 1 fig., 1 ref.

Energy Technology Data Exchange (ETDEWEB)

A semi-mechanistic model for calculating solid radionuclide release rates from bubbling pools of sodium was developed. The influence of particle spacial and size distributions on the decontamination of the releases was analysed and found significant. Decontamination factors are shown as a function of pool depth, bubbling characteristics and particle size distribution. The calculation of a decontamination factor for estimating the source term of large scale hypothetical core disruptive accidents is presented. The decontamination factor for a large scale accident was found to be two orders of magnitude greater than results obtained from small scale experiments conducted with uniform particle distributions.

Energy Technology Data Exchange (ETDEWEB)

Different sized ROIs within the femoral head and different modes of calculation were used in (/sup 99m/Tc)MDP scintimetry after femoral neck fracture. In preoperative scintimetry, correction for increased trochanteric uptake gave the best discrimination, whereas in postoperative scintimetry the direct ratio fractured/intact femoral head was superior. The change in ROI size had little influence.

Science.gov (United States)

The variation of metallic particle size and sample porosity significantly alters the dynamic mechanical properties of high density granular composite materials processed using a cold isostatically pressed mixture of polytetrafluoroethylene (PTFE), aluminum (Al), and tungsten (W) powders. Quasistatic and dynamic experiments are performed with identical constituent mass fractions with variations in the size of the W particles and pressing conditions. The relatively weak polymer matrix allows the strength and fracture modes of this material to be governed by the granular type behavior of agglomerated metal particles. A higher ultimate compressive strength was observed in relatively high porosity samples with small W particles compared to those with coarse W particles in all experiments. Mesoscale granular force chains of the metallic particles explain this unusual phenomenon as observed in hydrocode ...

International Nuclear Information System (INIS)

The size distributions of precipitated Ni clusters on the surface of a LaNi_5-based alloy immersed in alkaline solution (alkaline treatment) at 383 K for 0-110 min were precisely determined by combining superparamagnetic analysis and transmission electron microscopy (TEM) observations. The superparamagnetic analysis indicated that the diameters of the Ni clusters were smaller than #approx#25 nm in all samples, while their average values increased approximately from 5 to 9 nm with increasing alkaline treatment time. The spatial distribution of the Ni clusters was successively observed by TEM, which agreed fairly well with the estimated size distribution by superparamagnetic analysis. Therefore, estimation of the actual size distribution of Ni clusters by superparamagnetic analysis was proved to be feasible. Based on the above results, a precipitation process for Ni clusters by alkaline treatment is ...

International Nuclear Information System (INIS)

The activity concentrations of potassium, uranium and thorium in minerals and soil samples from a mining site in Ibadan, Southwestern Nigeria were measured using gamma ray spectroscopy method. Effective dose per annum has been calculated from the activity concentrations of dominant gamma-emitting natural radionuclides, potassium, uranium and thorium. Samples collected include minerals (beryl, quartz and feldspar), soil samples from the mining pits, heaps and undisturbed land around the mining site. The activity concentrations of "4"0K, "2"3"8U and "2"3"2Th, respectively in Bq kg-1 in the mineral samples were as follows: 1985 #+-# 16, 4.8 #+-# 0.9 and 11.8 #+-# 5.8 for beryl sample, 115.1 #+-# 27.9, 5.0 #+-# 1.3 and 6.3 #+-# 5.0 for feldspar samples and 1421 #+-# 122, <4.8 and 20.1 #+-# 3.5 for quartz samples. For the ...

International Nuclear Information System (INIS)

Convolution/superposition (C/S) is regarded as the standard dose calculation method in most modern radiotherapy treatment planning systems. Different implementations of C/S could result in significantly different dose distributions. This paper addresses two major implementation issues associated with collapsed cone C/S: one is how to utilize the tabulated kernels instead of analytical parametrizations and the other is how to deal with voxel size effects. Three methods that utilize the tabulated kernels are presented in this paper. These methods differ in the effective kernels used: the differential kernel (DK), the cumulative kernel (CK) or the cumulative-cumulative kernel (CCK). They result in slightly different computation times but significantly different voxel size effects. Both simulated and real multi-resolution dose calculations are presented. For simulation tests, we use arbitrary kernels and ...

Energy Technology Data Exchange (ETDEWEB)

The ventilation requirements for decontamination are normally determined with a static calculation method. In some cases, the pollutant emission is intermittent, for example in the car park of an office building, where all the cars enter and leave the place nearly at the same time. Generally, in such a case, the volume of the garage is large, consequently the time constant of the system has a high value. So a static approach would no longer stay accurate and a dynamic evaluation is needed. With the help of some assumptions, calculations remain rather simple and results can be plotted on nomographs or computed on a programmable handheld calculator. The amount of energy saved may appear very large in some cases. A sizing optimization will be required but also remains easy to compute. The paper presents the method of calculation for a single ventilation level and the optimization of a ...

Science.gov (United States)

... was log (s2) = 1.183 + 1.692 log (x) (r2 = 0.96; df = 1, 43; F = 1067.40; P kc was calculated according to Ruesink (1980), using 15. ... ...

British Library Electronic Table of Contents (United Kingdom)

The pore structure of volcanic clasts is examined using measurements of porosity, permeability, and electrical properties. Permeability varies by several orders of magnitude among volcanic clasts and does not depend solely upon porosity. Electrical property measurements of saturated volcanic samples illustrate the influence of pathway tortuosity and pore shape on permeability. For equivalent eruption conditions, silicic samples show higher tortuosities, smaller vesicle sizes, and lower permeabilities than mafic samples. These differences are largely due to variations in vesiculation and crystallization history. Differences between explosive and effusive samples reflect the relative ability of bubbles to form and maintain connected pathways during bubble expansion and collapse. Isotropic sa...

Energy Technology Data Exchange (ETDEWEB)

The transport of radon in concrete takes place through the complicated network of interconnected pores that is, at any time, the result of the process of hydration of cement and of moisture distribution and transport. Initially the microstructure of concrete depends on the mix proportions and curing conditions, its time-evolution being conditioned by its surrounding environment. Radon transport will be consequently a function of time, as it is influenced by the changing microstructure (total porosity and its distribution) and by the amount and distribution of the moisture contained in the pore system. A selection of information from the large amount of literature available on concrete is presented in chapter 2. A model that describes the process of hydration, of microstructure development and of moisture transport is presented in chapter 3. The physics of radon diffusion in homogeneous porous materials is outlined in chapter 4. The coupling of the numerical implementation of the ...

International Nuclear Information System (INIS)

The flux distributions and enhancement factors for various gas doser designs typically used in surface science applications and chemisorption studies have been calculated and compared. The following conclusions, which will aid the experimentalist in the choice of doser design, can be made. (1) The enhancement factor expected for a given doser can easily be derived from Fig. 2. (2) The optimum doser design is a multichannel array with a radius slightly larger than that of the sample, and a distance from the sample < 10% of the sample diameter. (Complications of this design are discussed.) (3) Because of space requirements, the sample--doser distance must sometime be > or =40% of the sample diameter, in which cases it is better to use a cosine emitter. A good, very simple doser design is described that consists of a small cosine emitter with a ...

Energy Technology Data Exchange (ETDEWEB)

This document provides data on aerosol concentrations in tank head spaces, total mass of aerosols in the tank head space and mass of aerosols sent to the exhauster during Rotary Mode Core Sampling from November 1994 through June 1999. A decontamination factor for the RMCS exhauster filter housing is calculated based on operation data.

International Nuclear Information System (INIS)

Full text: Optically stimulated luminescence (OSL) dating of individual sand-sized grains of quartz has advanced significantly over the past decade opening up new vistas in luminescence geochronology. Today, single-grain OSL dating can be used to constrain the burial ages of many deposits, including fluvial sediments, glaciofluvial material and archaeological sediments. It also provides a means of examining the stratigraphic integrity of archaeological sites where sediment mixing might have occurred. An OSL age is calculated by dividing the burial dose (the dose absorbed by the grain since it was last exposed to sunlight) by the environmental dose rate (the rate of supply of ionizing radiation to the grain over the period of burial). To obtain reliable OSL ages, therefore, an accurate estimate of the dose rate is required for each sample. Here we describe our OSL dating campaign at Vindija Cave, a key archaeological site in ...

Energy Technology Data Exchange (ETDEWEB)

The physical structure of a limestone or dolomite to be used in in-bed sulfur capture in fluidized bed boilers has great impact on the efficiency of sulfur capture and sorbent use. Therefore in process optimization and model calculations parameters describing the pore structure of these sorbents must be included. In this study an unreacted shrinking core model with variable effective diffusivity is applied to sulfation test data from a pressurized thermogravimetric apparatus (P-TGA) for various limestone and dolomite samples. The particle size was 250--300 {micro}m for all sorbents. The tests were done under typical conditions for a pressurized fluidized bed combustor, i.e. 850 C or 950 C, 15 bar, and were reported earlier at the 12th International Conference on Fluidized Bed Combustion. At these conditions the limestone remains uncalcined, while the dolomite is half-calcined. The sorbents were characterized by chemical ...

Science.gov (United States)

Scanning electron microscopy and an electron-microprobe analysis of a sample of blast furnace (BF) coke have revealed alkalization (5.64 wt % Na{sub 2}O + K{sub 2}O) and Al saturation (17.28 wt % Al{sub 2}O{sub 3}) of SiO{sub 2} by BF gases. The K/Na{sub at} value of 1.15 in the new phase (alteration zone) reflects close atomic proportions of the elements and suggests that the abilities to incorporate K and Na during the process are almost equal. This Al saturation and alkalization of SiO{sub 2} indicates an active role for Al along with alkali metals in BF gases. The average width of the altered area in the SiO{sub 2} grain is about 10 m, which suggests that SiO{sub 2} particles of that size can be transformed fully to the new phase, provided that at least one of their faces is open to an external pore (surface of the coke) or internal pore with circulating BF gases. The grains that exceed 10 {mu}m can only be partly altered, which means that ...

International Nuclear Information System (INIS)

In this paper heavy metal pollution at an abandoned Italian pyrite mine has been investigated by comparing total concentrations and speciation of heavy metals (Fe, Cu, Mn, Zn, Pb and As) in a red mud sample and a river sediment. Acid digestions show that all the investigated heavy metals present larger concentrations in the sediment than in the tailing. A modified Tessier's procedure has been used to discriminate heavy metal bound to organic fraction from those originally present in the mineral sulphide matrix and to detect a possible trend of metal mobilisation from red mud to river sediment. Sequential extractions on bulk and size fractionated samples denote that sediment samples present larger percent concentrations of the investigated heavy metals in the first extractive steps (I-IV) especially in lower dimension size fractionated samples suggesting that ...

Energy Technology Data Exchange (ETDEWEB)

Many monitoring activities require the collection of whole air samples over an extended time interval without loss or concentration of any atmospheric constituents. Described is the development and laboratory testing of a whole air sampler capable of collecting a 100 liter sample over a period of 0.63 days. The sampler has an empty weight of 7.79 kg and an overall size of 20.8-cm {times} 20.8-cm {times} 66.1-cm. The conceptual design for the development of smaller, higher-performance whole air samplers is also reported.

Energy Technology Data Exchange (ETDEWEB)

Stabilization/solidification of hazardous wastes is used to convert hazardous metal hydroxide waste sludge into a solid mass with better handling properties. This study investigated the pore size development of ordinary portland cement pastes containing metal hydroxide waste sludge and rice husk ash using mercury intrusion porosimetry. The effects of acre and the addition of rice husk ash on pore size development and strength were studied. It was found that the pore structures of mixes changed significantly with curing acre. The pore size shifted from 1,204 to 324 {angstrom} for 3-day old cement paste, and from 956 to 263 {angstrom} for a 7-day old sample. A reduction in pore size distribution for different curing ages was also observed in the other mixtures. From this limited study, no conclusion could be made as to any correlation between strength development and porosity. 10 ...

International Nuclear Information System (INIS)

Full text: A Large Sample Neutron Activation Analysis (LSNAA) facility is under development at GRR-1 research reactor, NCSR 'Demokritos'. The LSNAA facility design incorporates sample irradiation in the reactor's graphite thermal neutron column and subsequent measurement of the activity induced at a gamma spectroscopy system with gamma ray transmission measurement options included. Monte Carlo neutron and photon transport code MCNP-4C was used to model the facility. Appropriate correction factors accounting for neutron field perturbation during sample irradiation, high purity germanium detector efficiency for the volume source and gamma ray self-absorption within the sample itself were derived. The results of the computations were experimentally verified by activation foil measurements for a set of known materials and a range of sample sizes extending up to 10 ...

Energy Technology Data Exchange (ETDEWEB)

We present ab-initio calculations of the electronic structure of small Fe clusters (1-9 atoms) on Ni(001), Ni(111), Cu(001) and Cu(111) surfaces. Our focus is on the spin moments and their dependence on cluster size and shape. We derive a simple quantitative rule that relates the moment of each Fe atom linearly to its coordination number. Thus, for an arbitrary Fe cluster the spin moment of the cluster and of the individual Fe atoms can be readily found if the positions of the atoms are known. (orig.)

British Library Electronic Table of Contents (United Kingdom)

In this article we derive longitudinal impedance and wake function for an undulator setup with arbitrary undulator parameter, taking into account a finite transverse size of the electron bunch. Earlier studies considered a line density-distribution of electrons instead. We focus our attention on the long-wavelength asymptote (compared with resonance wavelength), at large distance of the electron bunch from the undulator entrance compared to the overtaking length, and for large vacuum-chamber size compared to the typical transverse size of the field. These restrictions define a parameter region of interest for practical applications. We calculate a closed expression for impedance and wake function that may be evaluated numerically in the most general case. Such expression allows us to deriv...

Energy Technology Data Exchange (ETDEWEB)

In this article, a method of producing elastic ferromagnetic composite containing particles of chemical pure iron with sizes of 0.10-0.15 mm was described. The particles were dispersed in an elastic matrix of an elastic silicone rubber. The filling factor of composite by ferromagnetic particles and porous factors were changed in the range from 0.15 to 0.45. The samples of the obtained composite were placed in the magnetic field with induction of 0-8 T, produced by the Bitter-type magnet. The longitudinal magnetostriction of samples was measured by using a coaxial capacitor with a movable plate. It was found that the maximal relative elongation of samples was 4.81% and hysteresis of magnetostriction and also remanent magnetostriction amounted to 1.08%. A slow decay of remanent magnetostriction up to 0.14% in 10{sup 5} s was also observed.

Energy Technology Data Exchange (ETDEWEB)

A new method for determining the year of birth, the year of death, and hence, the age at death, of post-bomb and recently deceased elephants has been developed. The technique is based on Accelerator Mass Spectrometry radiocarbon analyses of small-sized samples extracted from along the length of a ge-line of an elephant tusk. The measured radiocarbon concentrations in the samples from a tusk can be compared to the {sup 14}C atmospheric bomb-pulse curve to derive the growth years of the initial and final samples from the tusk. Initial data from the application of this method to two tusks will be presented. Potentially, the method may play a significant role in wildlife management practices of African national parks. Additionally, the method may contribute to the underpinnings of efforts to define new international trade regulations, which could, in effect, decrease poaching and the killing of very young ...

Energy Technology Data Exchange (ETDEWEB)

Aircraft constitute a unique environment which places stringent requirements on the instruments used to measure the concentrations of atmospheric trace gases and aerosols. Some of these requirements such as minimization of size, weight, and power consumption are general; others are specific to individual techniques. This review presents the basic principles and considerations governing the deployment of trace gas and aerosol instrumentation on an aircraft. An overview of common instruments illustrates these points and provides guidelines for designing and using instruments on aircraft-based measurement programs.

Energy Technology Data Exchange (ETDEWEB)

Physico-chemical studies were carried out on a sample of red mud collected from NALCO, Orissa, after calcination up to 1,200 C at an interval of 100 C. The observed change in properties like surface area, particle size, bulk density and mineral phases etc., can be profitably used while finding an appropriate application of this polluting waste from alumina plants.

International Nuclear Information System (INIS)

Nanocrystalline samples of Fe_8_0Mo_2_0 and Fe_5_0Mo_5_0 alloys were prepared by the mechanical milling method. The structure, lattice parameters, and crystallite size were determined by the X-ray diffraction. The magnetic properties of the milled products were determined by the Moessbauer spectroscopy. It was observed that in the case of the Fe_8_0Mo_2_0 alloy a solid solution of Mo in Fe was formed with the lattice parameters of the Fe increasing from 0.28659 nm to 0.29240 nm and the crystallite size decreasing from 250 nm to 20 nm. In the case of the Fe_5_0Mo_5_0 alloy there were no clear changes in values of the lattice parameters of Fe and Mo during the milling process, but the crystallite size decreased from 200 to 15 nm. Moessbauer spectra revealed different magnetic phases in the machanosynthesized Fe_Mo samples. In the case of the Fe_8_0Mo_2_0 alloy, the spectrum for the ...

Science.gov (United States)

During this reporting period four direct coal liquefaction experiments have been completed and a fifth is underway. These experiments have produced conversion and selectivity data on samples of Utah coal slurried in tetralin and catalyzed using iron-titanium hydride. Hydrogen loading of the alloy, catalyst particle size, coal particle size, operating temperatures for alloy addition and liquefaction without the catalysts present, have all been studied during these four experiments. Conversions of 61% DAF in 30 min have been recorded at 485/sup 0/F and 520 psia. The fifth run using the same coal at a reduced particle size has begun, after which we will move to samples of Kentucky and Alabama coals. Equipment manufacture, delivery, and installation delays, totaling over 6 months, greatly reduced the time available for research, making a 6 month no cost extension necessary. The extended ...

International Nuclear Information System (INIS)

Muonic-atom energy levels and wave functions are calculated. The results are corrected for nearly all important static effects, including finite nuclear size as produced by a user-specified nuclear charge distribution. Fourth-order Runge-Kutta integration of the radial Dirac equations, with the secant method determining the eigenvalues. Corrections are either included as potentials in the Dirac equations or computed as first-order perturbations. The code assumes spherical symmetry, so that effects of nuclear deformation may be treated only as static first-order perturbations. Dynamic muon-electron and muon-nuclear effects are neglected (the latter are calculated by RURP). (Auth.).

International Nuclear Information System (INIS)

The convolution/superposition calculations for radiotherapy dose distributions are traditionally performed by convolving polyenergetic energy deposition kernels with TERMA (total energy released per unit mass) precomputed in each voxel of the irradiated phantom. We propose an alternative method in which the TERMA calculation is replaced by random sampling of photon energy, direction and interaction point. Then, a direction is randomly sampled from the angular distribution of the monoenergetic kernel corresponding to the photon energy. The kernel ray is propagated across the phantom, and energy is deposited in each voxel traversed. An important advantage of the explicit sampling of energy is that spectral changes with depth are automatically accounted for. No spectral or kernel hardening corrections are needed. Furthermore, the continuous sampling of photon ...

CERN Document Server

Monte Carlo calculations of proton irradiation of permanent magnets for the TRADE experiment have been performed. An irradiation dose of about 4´106 Gy/yr/mA has been estimated due to beam losses in normal operating conditions. Existing experimental results indicate that this irradiation level may induce a considerable demagnetization: in fact, a dose of 6´107 Gy induces a remanence loss of 0.3 % on samples of Sm2Co17 magnets, which are the most resistant type. More detailed calculations with the final design of the magnets and of the beam line are suggested, to determine if the irradiation levels allowed a reliable operation of the permanent magnets for the entire duration of the TRADE experiment. Damage and gas production rates have also been calculated; the values obtained are very low, thus confirming that the demagnetization process is in great part reversible.

CERN Document Server

Context. Study of open clusters is important not only for learning properties of these objects but also for understanding the process of formation and evolution of stars and the Milky Way. Aims. The paper contains determination of the global (geometrical and physical) characteristics of a large sample of Galactic open clusters from homogeneous near-infrared photometric data and analysis of mutual relations between those characteristics. Methods. The near-infrared JHK photometric data from the 2-Micron All Sky Survey were used to determine new coordinates of the centres, angular sizes and radial density profiles of 849 open clusters in the MilkyWay. Additionally, for 754 of these clusters age, reddening, distance and linear sizes were also derived. The sample contains 140 open clusters which have not been studied before. Results. The analysed sample contains open clusters with ages ...

Energy Technology Data Exchange (ETDEWEB)

We review recent development in separations and mass spectrometric instrumentation for sensitive and high-throughput proteomic analyses. These efforts have been primarily focused on the development of high-efficiency (separation peak capacity of ~103) nanoscale liquid chromatography (nanoLC; e.g., flow rates extending down to ~20 nL/min at optimal separation linear velocities through narrow packed capillaries) in combination with advanced mass spectrometry (MS), including high sensitivity and high resolution Fourier transform ion cyclotron resonance (FTICR) MS. This technology enables MS analysis of low nanogram-level proteomic samples (i.e., nanoscale proteomics) with individual protein identification sensitivity at the low zeptomole-level. The resultant protein measurement dynamic range can reach 106 for nanogram-sized proteomic samples, while more abundant proteins can be detected from complex sub-picogram ...

Energy Technology Data Exchange (ETDEWEB)

We calculate the exclusion region in the parameter space of {nu}{sub {mu}} {yields} {nu}{sub e} oscillations of the LSND type using a combined fit to the reconstructed energy distributions of neutrino candidate samples from the MiniBooNE data obtained with two different particle identification methods. The two {nu}{sub e} candidate samples are included together with a high statistics sample of {nu}{sub {mu}} events in the definition of a {chi}{sup 2} statistic which includes the correlations between the energy intervals of all three samples and handles the event overlap between the {nu}{sub e} samples. The {nu}{sub {mu}} sample is introduced to constrain the effect of systematic uncertainties. This analysis increases the exclusion limit in the region {Delta}m{sup 2} {approx}< 1eV{sup 2} when compared with the result previously ...

International Nuclear Information System (INIS)

We study the Anderson model on a two-dimensional square lattice with an applied weak magnetic field B which causes the hopping matrix elements to have Peierls phase factors. The recursion method is applied and B dependent conductivity ?(B) is calculated from the Kubo formula for different system sizes and degree of disorder W . For large W there is no systematic change of ?(B) with B, it shows a fluctuating behavior.

Energy Technology Data Exchange (ETDEWEB)

A microemulsion comprised of water, Brij 78, pentanol and styrene into which PPO and bis-MSB had been dissolved was prepared. Polymerization of the styrene resulted in a suspension of fluor-containing polystyrene nanoparticles (<100 nm). After a concentration step, the aqueous nanosuspension was able to detect {sup 14}C with counting efficiencies over 50% of those of a commercially available scintillation cocktail. Monte Carlo calculations demonstrated that the size and concentration of the nanoparticles were appropriate for optimum detection efficiency.

Energy Technology Data Exchange (ETDEWEB)

Total hemispherical emittance was measured for the SP-100 reactor fuel cladding alloy (Nb-l% Zr). Based on a standard test method (ASTM C 835-82), experiments were conducted on a reference sample of oxidized stainless steel and then on a sample of actual cladding. The sample is heated in a vacuum by passing DC current through it until reaching equilibrium. Measurements are made of the electrical power dissipated in the sample and of the surface temperature. Using the Stefan-Boltzmann Law and some key assumptions concerning conductive and radiative heat transfer, the measured quantities are used to calculate emittance. Calculated values for unoxidized cladding range from 0.159 +/- 5.35% at 913 K to 0.200 +/- 4.51% at 1091 K. Highest value measured after onset of visible oxidation was 0.339 +/- 3.92% at 1269 K.... SP-100, Reactor, Emittance, Niobium, Fuel ...

International Nuclear Information System (INIS)

The electronic structures of BaSnO_3, BaSbO_3, and BaPbO_3, calculated using an extended general-potential linearized augmented-plane-wave method, are reported. The electronic structures of BaSnO_3 and its 6s analog BaPbO_3 are found to be very different, explaining the absence of superconductivity in the Ba(Sn,Sb)O_3 system. These differences are explained by a combination of the relativistic lowering of the 6s states and ion-size effects. Muffin-tin-approximation augmented-plane-wave calculations for BaSnO_3 are also reported and the utility of the muffin-tin approximation for this and similar materials is discussed in terms of the differences between the two sets of calculations.

British Library Electronic Table of Contents (United Kingdom)

A method to achieve NMR of dilute samples in the earth's magnetic field by applying para-hydrogen induced polarization is presented. Maximum achievable polarization enhancements were calculated by numerically simulating the experiment and compared to the experimental results and to the thermal equilibrium in the earth's magnetic field. Simultaneous 19F and 1H NMR detection on a sub-milliliter sample of a fluorinated alkyne at millimolar concentration (1018 nuclear spins) was realized with just one single scan. A highly resolved spectrum with a signal/noise ratio higher than 50:1 was obtained without using an auxiliary magnet or any form of radio frequency shielding.

International Nuclear Information System (INIS)

The use of the method is described on powder samples before and after sintering with an La content of up to 1%. For excitation of the K series of La a _2_4_1Am source with an activity of 1.11 GBq was used. The obtained results showed that the method is sufficiently accurate (error 7%) at a short period of measurement (100 s). It gives satisfactory results even in the comparison of the experimental relative count rate and the theoretically calculated value despite the fact that the analytical signal comes from the sample surface. (Ha).

Energy Technology Data Exchange (ETDEWEB)

A new theory has been developed to calculate the steady state temperature profile in a cylindrical sample positioned along the entire axis of a cylindrical microwave cavity. Temperature profiles were computed for alumina rods of various radii contained in a cavity excited in one of the TM{sub 0n0} modes with n = 1, 2 or 3. Calculations were also performed with a concentric outer cylindrical tube surrounding the rod to investigate hybrid treating. The parametric studies of the total sample center and surface temperatures were performed as a function of the total power transmitted into the cavity. Also, the total hemispherical emissivity was varied at boundaries of the rod, surrounding tube, and cavity walls. The results are discussed in the context of controlling the average rod temperature and the temperature distribution in the rod during microwave processing.

International Nuclear Information System (INIS)

For the Convolution, Superposition and Monte Carlo methods, energy spectrum data is an essential parameter. Especially, by using Monte Carlo method, if the adequate properties of electrons are set, complex energy spectrum data can be calculated by simple input. However, adjustment of the property of electrons incident on the target of linear accelerator is time-consuming procedure. To cover the difference of many accelerators, it is important how we obtain accurate energy spectrum by simple methods. Especially, the total accuracy of dose calculation depends on the agreement of measured and calculated percentage depth dose (PDD) and off-axis ratio (OAR). Thus, a simple method for the determination of the simulation parameters was considered. To reduce the adjustment procedure, we selected values of important three parameters, which were the mean energy of the input electron beam, the energy distribution of the input electron ...

International Nuclear Information System (INIS)

We study the relation between size and star formation activity in a complete sample of 225 massive (M_* > 5 x 10"1"0 M _s_u_n) galaxies at 1.5 < z < 2.5, selected from the FIREWORKS UV-IR catalog of the CDFS. Based on stellar population synthesis model fits to the observed rest-frame UV-NIR spectral energy distributions, and independent MIPS 24 #mu#m observations, 65% of the galaxies are actively forming stars, while 35% are quiescent. Using sizes derived from two-dimensional surface brightness profile fits to high-resolution (FWHM_P_S_F #approx# 0.''45) ground-based ISAAC data, we confirm and improve the significance of the relation between star formation activity and compactness found in previous studies, using a large, complete mass-limited sample. At z #approx# 2, massive quiescent galaxies are significantly smaller than massive star-forming galaxies, and a median factor of 0.34 #+-# 0.02 ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Incomplete dispersion of aggregates is a well known difficulty when analyzing soil texture of Andosols, particularly if no fresh soil material is available. To facilitate such investigations, several dispersion procedures were carried out on air dried samples rich in short range order minerals, originating from selected Andosol profiles (S Mexico). As a result, we propose an improved method based on a sequential chemical treatment with K oxalate, NH4 oxalate, and oxalic acid that reliably removes cementing agents and allows for a stable dispersion of soil particles after addition of Na pyrophosphate. This method was proved to be well reproducible and highly reliable for routine grain size determinations. The potential error caused by the inherent risk of dissolving primary mineral...

International Nuclear Information System (INIS)

Pure Cu of 99.98 wt.% purity has been processed at room temperature by diverse techniques of severe plastic deformation, namely equal-channel angular pressing (ECAP), high pressure torsion (HPT) and a combination of both in order to find out the evolution on the microstructural homogeneity for each of the processes and their combination. Starting with a grain size of #approx#60 #mu#m, severe plastic deformation has been introduced to the material while maintaining the sample dimensions unchanged through the processes of ECAP and HPT. A significant decrease in grain size was observed by transmission electronic microscopy (TEM). Microtensile and microhardness tests were carried out on the deformed material in the three processing conditions. A significant improvement of the tensile strength was promoted with admissible penalization on ductility.

Energy Technology Data Exchange (ETDEWEB)

The starting material for two certified and one candidate reference material was obtained from dried grass specially cultivated on a selected and well prepared soil. The Community Bureau of Reference (BCR) of the Commission of the European Communities produced two certified reference materials (CRM`s) from this dried grass: a rye grass material (CRM 281) certified in 1988 for the quality control of trace and toxic element analyses and a hay powder material (CRM 129) certified in 1989 for monitoring trace and minor elements. A fraction of the dried grass was used in 1993 for the preparation of a hay powder with a particle size of < 63 {mu}m using newly developed grinding techniques. This paper compares the production methods of these three materials and the obtained particle size distribution of the powders. The analytical evaluation of these production methods was carried out by solid sampling Zeeman atomic absorption ...

International Nuclear Information System (INIS)

Using high-resolution y-rays spectrometry, the natural radioactivity of 14 samples of natural and o manufactured Egyptian building materials have been investigated. The samples were collected from local market and construction sites. From the measured gamma-ray spectra, specific activities were determined. The radium equivalent activity in each sample was estimated. Radiological evaluations of these materials indicate that all materials meet the external gamma-ray dose limitation. Calculation of concentration indices by assuming a Markkanen room model is constructed from these materials, to find the excess gamma-ray dose taken over that received from the outdoors. The Austrian Standard ONORM S 5200 is used in testing the building materials.

International Nuclear Information System (INIS)

The influence of hydrogen ion implantation into the channel polysilicon of polysilicon thin film transistors on gate oxide conductivity has been investigated. Data for effective tunnelling barriers at the gate oxide/channel polysilicon interface are presented. A value of 1.2eV for samples with boron doped channel polysilicon is calculated. For hydrogenated boron doped samples tunnelling barriers higher than 2.1 eV are obtained. The tunnelling barriers for phosphorus doped samples are impurity concentration dependent and decrease with increasing phosphorus concentration in the range 3 x 10"1"7 to 3 x 10"1"9 cm"-"3. (Author).

International Nuclear Information System (INIS)

A dense silica glass was prepared by consolidating a highly dispersed silicic acid powder (particle size 1H magic-angle spinning (MAS) NMR confirmed an increase in hydroxyl groups in the sample prepared by SPS relative to that of the conventional SiO2 reference glass. Aside from the comparably high water content, we conclude from the similarity of the IR-reflectance and the 29Si MAS NMR spectra of the SPS sample and the corresponding spectra of the conventionally prepared silica glass, that the short- and medium-range order is virtually the same in both materials. Raman spectroscopy, however, suggests that the number of three- and four-membered rings is significantly smaller in the SPS sample compared to the conventionally prepared sample. Based on these results we conclude that it is possible to prepare glasses by compacting amorphous powders by the SPS process. The SPS process may ...

International Nuclear Information System (INIS)

Service water, 100 l each, was collected at an intake of a water treatment plant and at a tap after water was left running for five minutes. The carriers of strontium and cesium were added to water immediately after sampling, and the sample was vigorously stirred and filtered. Then it was passed through a cation exchange column at a rate of 80 ml/min. Strontium and cesium were eluted with hydrochloric acid from the cation exchange column, and separated. After the radiochemical separation, the mounted precipitates were counted for activity using low background beta counters normally for 60 min. Net sample counting rates were corrected for counter efficiency, recovery, self absorption and decay to obtain the content of strontium-90 and cesium-137 radioactivity per sample aliquot. From the results, concentrations of these nuclides in the original sample were ...

International Nuclear Information System (INIS)

The molar heat capacities (Cp,m) of a series of synthetic forsterite (Fo)-fayalite (Fa), (Mg2SiO4+Fe2SiO4), olivines have been measured between 5K and 300K on milligram-sized samples with the Physical Properties Measurement System (Quantum Design(R)). Sharp, ?-type heat capacity anomalies are observed in the Fe-rich compositions fayalite, Fo10Fa90, Fo20Fa80, Fo30Fa70, and Fo40Fa60. The corresponding Neel temperatures TN decrease linearly from 64.5K in fayalite to 32.8K in Fo40Fa60 following the relationship TN=79.02.xFa-14.07. Fo50Fa50 and Mg-richer olivines show weak broad features in the heat capacity data around 15K to 20K that decrease in magnitude with increasing forsterite content. In order to derive and separate molar electronic, magnetic and vibrational heat capacity contributions, Cel,m, Cmag,m, and Cvib,m from the experimental heat capacities (Ctot,m), we used a single-parametric phonon dispersion model to ...

CERN Document Server

We present a study of the mid-infrared properties and dust content of a sample of 27 HII ``blobs'', a rare class of compact HII regions in the Magellanic Clouds. A unique feature of this sample is that even though these HII regions are of high and low excitation they have nearly the same physical sizes ~1.5-3 pc. We base our analysis on archival 3-8 microns infrared imagery obtained with the Infrared Array Camera (IRAC) on board the Spitzer Space Telescope. We find that despite their youth, sub-solar metallicity and varied degrees of excitation, the mid-infrared colors of these regions are similar to those of typical HII regions. Higher excitation ``blobs'' (HEBs) display stronger 8 micron emission and redder colors than their low-excitation counterparts (LEBs).

British Library Electronic Table of Contents (United Kingdom)

Vanadium carbide is the most effective grain growth inhibitor for ultrafine WC-Co composites due to its high solubility and mobility in the cobalt phase at relatively low temperatures; however, there are still some debates over the best way to introduce it into the WC-Co formulation. In this paper, the differences between admixed and chemically doped grain growth inhibitors on the microstructural development and properties of an ultrafine WC-10Co composite are discussed. The densification rate of chemically doped samples is slower in the early stage of sintering and the WC grain sizes of the sintered alloys are finer than those of admixed samples, leading to the increase of hardness and transverse rupture strength of the sintered alloys. The effectiveness of the chemically doped inhibitor ...

British Library Electronic Table of Contents (United Kingdom)

A test bench was designed and assembled to carry out impact tests on samples and components. The system allows simple and rapid adjustment of the test parameters, such as the shot size and air pressure, with good repeatability of the results. Tests on steel and light alloys were carried out under both as-produced condition and on thin hard-coated samples. Significant reductions in dimple dimensions were seen after coating. FE models simulating the experiments overestimated the dimple depths, although the parameter trend was satisfactorily captured. The residual stresses from coating and shot peening determined numerically are believed to have been proven effective against fatigue.

Energy Technology Data Exchange (ETDEWEB)

In this study, isothermal torsion tests were carried out on magnesium AZ31B alloy under constant strain rate conditions, in the range of 250 to 400 C at 0.01, 0.1, and 1.0 s{sup -1}. Alloy flow stress dependence on strain rate and temperature can be described by a power law with activation energy of 130 kJ/mol. Microstructural examination of hot deformed samples shows very fine recrystallized grains decorating grain boundaries of larger gains in the form of a necklace. These fine grains are produced by dynamic recrystallization at the grain boundaries of original grains. Microstructure evolution, based on samples quenched at different strain levels, indicates that increasing deformation strain has little effect on recrystallized grain size but widens the recrystallized region, with full recrystallization achieved at a certain high strain level. Recrystallized grain size increases with increasing ...

Energy Technology Data Exchange (ETDEWEB)

Chemical-looping combustion is a promising technology for the combustion of gas or solid fuel with efficient use of energy and inherent separation of CO{sub 2}. Chemical-looping combustion of methane with calcium sulfate as a novel oxygen carrier was conducted in a laboratory scale fixed bed reactor. The effects of reaction temperature, gas flow rate, sample mass, and particle size on reduction reactions were investigated and an optimum operating condition was determined. The results show that this novel oxygen carrier has a high reduction reactivity and stability in a long-time reduction/oxidation test. The conversions of CH{sub 4} increased with a higher temperature, smaller gas flow rate, larger sample mass and smaller particle size. The suitable reaction temperature seems to be around 950 C. Low temperatures lead to a low CH{sub 4} conversion, but a significant SO{sub 2} formation was observed at a ...

International Nuclear Information System (INIS)

Nanocrystalline powders of GaN with grain sizes ranging from 2 to 30 nm were examined under high external pressures by in situ diffraction techniques in a diamond anvil cell at DESY (HASYLAB, Station F3). The experiments on densification of pure powders under high pressure were performed without a pressure medium. The mechanism of generation and relaxation of internal strains and their distribution in nanoparticles was deduced from Bragg reflections recorded in situ under high pressures at room temperature. The microstrain was calculated from the full-width at half-maximum (FWHM) values of the Bragg lines. It was found that microstrains in GaN crystallites are generated and subsequently relaxed by two mechanisms: generation of stacking faults and change of the size and shape of the grains occurring under external stress. (author)

Science.gov (United States)

A method for determining the critical debond size between the facesheet and the core in composite sandwich panels under in-plane compression is described. The approach uses fracture mechanics together with a buckling criterion for a debonded faceskin. The technique yields predictions for the critical in-plane compressive load for debond propagation as a function of core-to-faceskin debond size, faceskin thickness, lay-up, composite material properties, and honeycomb properties and geometry. A computer program, developed in this work, calculates the critical buckling load and facesheet deformed shape by solving an eigenvalue problem. The output predicts, for several cases, critical initial debond lengths comparable to those that have been observed on tests on sandwich panels.

International Nuclear Information System (INIS)

A general theoretical scheme to describe the effective modulus and mass density for acoustic metamaterials is presented. For such a purpose, an effective medium theory of a one-dimensional acoustic waveguide containing subwavelength-sized Helmholtz resonators is formulated. It is shown that, when the wavelength is much larger than the periodic length and the size of the resonators, the whole composite structure can be treated as an effective homogeneous medium in accounting for its acoustic properties. It is also shown that the acoustic characteristics, such as the effective modulus and the effective mass density, can be determined precisely from the transmission and the reflection data. The calculated effective modulus and effective mass density confirm that this structure behaves as a homogeneous metamaterial with a negative effective modulus in a frequency range just above the resonant frequency.

Science.gov (United States)

The results of a computational scheme of Rose (a method for calculating solutions of parabolic equations with free boundary, Math. Comp., 14: 249-256(1960)) are compared with the known analytic solution of a single-phase Stefan problem with constant boundary temperature. Rose's scheme was implemented in FORTRAN on a DEC PDP-10. Computations were performed for Stefan numbers St = 0.01, 0.1, 1, 10, and 100. Three relative mesh sizes (..gamma.. = DT/(DX)/sup 2/ = 1/2, 1/6, and 1/25) were used. For each St, the relative mesh size had very little effect on accuracy. However, taking ..gamma.. = 1/25 resulted in dramatically increased computing time. The relative errors of temperature were large near the phase change front. 11 figures, 5 tables.

CERN Document Server

We identify emission lines of post-iron peak elements in very high signal-to-noise spectra of a sample of planetary nebulae. Analysis of lines from ions of Kr and Xe reveals enhancements in most of the PNe, in agreement with the theories of s-process in AGB star. Surprisingly, we did not detect lines from Br even though s-process calculations indicate that it should be produced with Kr at detectable levels.

British Library Electronic Table of Contents (United Kingdom)

In this work, we report the preparation of lead titanate (PT) nanoceramics (with an average grain size of ~200nm in diameter) by using hydrothermal PT nanoparticles as start materials and characterized the dielectric and ferroelectric properties. The dielectric constant of the ceramic was found to be ~180 (at 1kHz) at room temperature and reached a maximum value of 8330 at ~490^oC, suggesting that the Curie temperature of the nanoceramics is consistent with the known value of PT crystals. Ferroelectric domains and hysteresis loops were obtained through piezoelectric force microscopy measurements, which provide direct and clear evidence for the ferroelectricity in the nanoceramic samples.

International Nuclear Information System (INIS)

Conduction properties of Rb"+ ion in Rb-Al-priderite and K"+ ion and Rb"+ ion in (K,Rb)-Al-priderite, were investigated by NMR using "2"7Al in the framework as a probe. Size effect was observed remarkably in the activation energies. Frequency dependence of T_1 in Rb-Al-priderite at a low temperature indicates that the relaxation behavior of "2"7Al in Rb-Al-priderite can be described by the continuum model. Barrier height distributions and 'attempt frequencies' in both samples obtained by a curve-fitting method are discussed in comparison with those of K-Al-priderite. (orig.).

CERN Document Server

We give a general local central limit theorem for the sum of two independent random variables, one of which satisfies a central limit theorem while the other satisfies a local central limit theorem with the same order variance. We apply this result to various quantities arising in stochastic geometry, including: size of the largest component for percolation on a box; number of components, number of edges, or number of isolated points, for random geometric graphs; covered volume for germ-grain coverage models; number of accepted points for finite-input random sequential adsorption; sum of nearest-neighbour distances for a random sample from a continuous multidimensional distribution.

Energy Technology Data Exchange (ETDEWEB)

Gaussian-process models are developed to detect genetic linkage using complete high-resolution maps of identity by descent between affected relative pairs. Approximations are given for the significance level and power of the likelihood-ratio test of no linkage and for likelihood-ratio confidence regions for trait loci. The sample sizes required to detect linkage by using different classes of affected relative pairs are compared, and the problem of combining data from different classes of relatives is discussed. 23 refs., 2 figs.

Energy Technology Data Exchange (ETDEWEB)

Praseodymium-doped Bi{sub 4}Ti{sub 3}O{sub 12} (BIT) with various compositions of dopant, Pr (x = 0.5, 0.6, 0.7, 0.8) in Bi{sub 4-x}Pr{sub x}Ti{sub 3}O{sub 12} (BPT) were synthesized using a low temperature wet chemical technique. Powders calcined at 800 deg. C exhibit a single phase polycrystalline perovskite bismuth-layered structure. Randomly oriented plate-like structures were observed under Scanning Electron Microscope (SEM). A small amount of Pr doping (x = 0.5) resulted in dramatically reduced of grain size from 2 {mu}m to less than 50 nm in which Pr plays the role as a grain growth inhibitor. However, by increasing the composition of Pr, bigger grain size of up to 1 {mu}m was observed for x = 0.8 that was caused by diffusion of Pr in the perovskite structure. Dielectric properties showed that dielectric permittivity decreased with the addition of x = 0.50, and increasing with further addition of Pr. Dissipation factor (tan {delta}) ...

Energy Technology Data Exchange (ETDEWEB)

We present an atomistic simulation of the Ostwald ripening of extrinsic defects (clusters, {l_brace}1 1 3{r_brace}s and dislocation loops) which occurs during annealing of ion implanted silicon. The model describes the capture and emission of Si interstitial atoms to and from extrinsic defects of sizes up to thousands of atoms and includes a loss term due to the flux of interstitials to the recombining surface. Key input parameters of the simulation are the variations of the formation energy and of the capture efficiency with the size of the different defects. This model shows that the kinetics of the well-known dissolution of {l_brace}1 1 3{r_brace} defects is only driven by the recombination efficiency at the surface and the distance from the defects to the sample surface. We have subsequently used this model to study defect evolution in low and ultra low energy (ULE) B implanted Si during annealing. Defect dissolution ...

Energy Technology Data Exchange (ETDEWEB)

Powders with nominal compositions (in atomic percent) Ti-48Al and Ti-48Al-2Nb-2Cr were prepared by the plasma rotating electrode process (PREP) and gas atomization (GA) techniques. As-solidified and heat-treated (1000degC per 3 h) powder samples were examined by metallography, scanning electron microscopy, X-ray diffraction and transmission electron microscopy. The microstructures of the powders were characterized as a function of atomization technique, alloy content, powder particle size (solidification rate) and thermal history. All of the as-solidified powders were comprised of disordered [alpha], and ordered [alpha][sub 2]-Ti[sub 3]Al and [gamma]-TiAl. For both alloys, a larger volume fraction of [alpha] and [alpha][sub 2] was observed in the PREP powders relative to GA powders of comparable size. Additionally, for both alloys and both atomization techniques, the volume fraction of [alpha][sub 2] was observed to ...

Energy Technology Data Exchange (ETDEWEB)

Municipal solid waste incineration (MSWI) bottom ash contains economically significant levels of silver and gold. Bottom ashes from incinerators at Amsterdam and Ludwigshafen were sampled, processed, and analyzed to determine the composition, size, and mass distribution of the precious metals. In order to establish accurate statistics of the gold particles, a sample of heavy non-ferrous metals produced from 15 tons of wet processed Amsterdam ash was analyzed by a new technology called magnetic density separation (MDS). Amsterdam's bottom ash contains approximately 10 ppm of silver and 0.4 ppm of gold, which was found in particulate form in all size fractions below 20 mm. The sample from Ludwigshafen was too small to give accurate values on the gold content, but the silver content was found to be identical to the value measured for the Amsterdam ash. Precious metal value in ...

Energy Technology Data Exchange (ETDEWEB)

The real-time dose assessment system under development has been updated and the technology for tracer experiment has been established. The calculation of external gamma dose is the most difficult and time-consuming part of the dose calculations. The characteristics of external gamma exposure have been investigated and the method for reducing the calculation time has been devised. The internal exposure via the ingestion of the contaminated foodstuffs is one of the important pathways to the total radiological exposure. In the emergency, it is necessary to take an action such like food ban to protect the internal exposure. An algorithm for the interface between the real-time system and the food chain model has been provided. The second field tracer experiment over flat terrain has been carried out on a plain in Iksan city in Junrabook-Do. Sequential tracer sampler which can be sampled the tracer gas over ...

International Nuclear Information System (INIS)

The purpose of this study is to evaluate the accuracy of dose calculations by three algorithms. Depth dose, OPF (Output Factor) and dose profiles were measured in a heterogeneous phantom. These values were also calculated by three algorithms of the Batho power law (BPL), Equivalent-Tissue Air Ratio (ETAR) and Convolution superposition (CS). The data were obtained for 4, 6 and 10 MV photon beams with a linear accelerator (Varian 21EX). Field size ranged from 3 x 3 cm"2 to 10 x 10 cm"2. Dose profiles of beam penumbra were also measured by a 0.125 ml ionization chamber at the point of 8, 13 and 18 cm from the surface of the phantom at intervals of 1 mm. Differences between measured and calculated depth doses were within 2% in BPL and CS, but depth doses were overestimated in ETAR. OPFs were also overestimated with the error of more than 4% in ETAR. Absorbed dose calculated by CS were ...

International Nuclear Information System (INIS)

The paper introduces the disposal procedures of the old reactor pressure vessel head. Reactor pressure vessel (RPV) heads were replaced successfully in Daya Bay Nuclear Power Plant. The on-site treatment and disposal of replaced heads was thereafter implemented. This is the first time in China for large size radioactive article disposal. To guarantee the safety of old head treatment, issues of radiation protection have to be taken into account. Dose rate distribution of the old head surface and radioactivity were initially calculated according to the operation history and the neutron flux rate of the reactor. Shielding calculation and package design was thereafter worked out based on the data obtained from the old head, e.g. neutron flux, sorts of nuclides, radioactivity and dose rates. Shielding package was afterwards manufactured in special factories and transported to Daya Bay NPP site by truck and ship. The shielding ...

Energy Technology Data Exchange (ETDEWEB)

There are few studies that focused on the prognostic value of FDG-PET on small cell lung cancer (SCLC). Not only FDG uptake (maxSUV), but also metabolic size (greatest dimension of PET positive mass) may determine the prognosis of SCLC. Here, we investigated the prognostic significance of maxSUV, and the metabolic size in SCLC patients. Biopsy-proven SCLC patients (n=21; age, means.d.=67.39y; male: female=19: 3) who had underwent FDG-PET within 4 weeks of chemotherapy initiation were enrolled. There were 7 extensive disease (ED) and 14 limited disease (LD) patients. The maxSUV and the metabolic size were measured, and then, size-incorporated maxSUV (SIMaxSUV = maxSUV x metabolic size) were calculated at individual SCLC masses. SIMaxSUV of main lesion (main-SIMaxSUV), and the summed value of SIMaxSUV of all PET positive masses (summed-SIMaxSUV) were obtained. In ...

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The surface losses in the drift-tube linac (DTL) tanks 3 and 4 of the LANSCE linear accelerator are calculated using 3-D electromagnetic modeling with the CST MicroWave Studio (MWS). The results are used to provide more realistic power estimates for the 201.25MHz RF upgrade design within the LANSCE-R project. We compared 3-D MWS results with those from traditional 2-D Superfish computations for DTL cells and their simplified models and found differences on the level of a few percent. The differences are traced to a 3-D effect consisting in a redistribution of the surface currents on the drift tubes (DT) produced by the DT stem. The dependence of MWS results on the mesh size used in computations is also discussed.

Science.gov (United States)

Rapid administration of stable iodine is essential for the saturation and subsequent protection of the thyroid gland against the potential harm caused by radioiodines. This paper proposes the Dutch risk analysis that uses an atmospheric dispersion model to calculate the size of the zones around nuclear power plants where radiological thyroid doses for children might be sufficiently high to warrant iodine administration. Dose calculations for possible releases from the nuclear power plants of Borssele (The Netherlands), Doel (Belgium) and Emsland (Germany) are based on two scenarios in combination with a 1-y set of authentic, high-resolution meteorological data. The dimensions of the circular zones were defined for each nuclear power plant. In these zones, with a radius up to 50 km, distribution of stable iodine tablets is advised. PMID:20332130

International Nuclear Information System (INIS)

Ionizing radiations that differ in number, size, and distribution of energy deposition events might be expected to cause different effects for the same absorbed dose. Furthermore, microdosimetry calculations suggest that large variations in biological effectiveness might be expected for internally deposited alpha-emitting radionuclides for the same absorbed dose, depending upon the specific activity and spatial distribution of the sources in tissue. The study described in this article was designed to demonstrate these phenomena in vitro. Cultured Chinese hamster ovary (CHO-K1 BH4) cells were exposed in vitro to inert, insoluble ceramic microspheres in zirconium dioxide labeled with "2"3"9Pu. The average exit energy of the 5.15 MeV alpha particle was calculated to be 4.3 MeV. Exposure times varied from four to seven hours to achieve the desired dose level.

International Nuclear Information System (INIS)

Magnetic properties of the Al1-xGaxFeO3 family of oxides crystallizing in a non-centrosymmetric space group have been investigated in detail along with structural aspects by employing X-ray and neutron diffraction, Moessbauer spectroscopy and other techniques. The study has revealed the occurrence of several interesting features related to unit cell parameters, site disorder and ionic size. Using first-principles density functional theory based calculations, we have attempted to understand how magnetic ordering and related properties in these oxides depend sensitively on disorder at the cation site. The origin and tendency of cations to disorder and the associated properties are traced to the local structure and ionic sizes. -- Graphical abstract: We have studied both experimentally and theoretically the important role of disorder at the cation site on magnetic and related properties of the Al1-xGaxFeO3 family of oxides ...

CERN Document Server

In this article we derive longitudinal impedance and wake function for an undulator setup with arbitrary undulator parameter, taking into account a finite transverse size of the electron bunch. Earlier studies considered a line density-distribution of electrons instead. We focus our attention on the long-wavelength asymptote (compared with resonance wavelength), at large distance of the electron bunch from the undulator entrance compared to the overtaking length, and for large vacuum-chamber size compared to the typical transverse size of the field. These restrictions define a parameter region of interest for practical applications. We calculate a closed expression for impedance and wake function that may be evaluated numerically in the most general case. Such expression allows us to derive an analytical solution for a Gaussian transverse and longitudinal bunch shape. Finally, we study the feasibility ...

Energy Technology Data Exchange (ETDEWEB)

The important amount of hydration water in the ulexite (NaCaN{sub 5}O{sub 9}.8H{sub 2}O), allows using calcination methods to increase its B{sub 2}O{sub 3} content. This paper analyses the thermal decomposition reaction of a preconcentrated ulexite through weight loss measurements, which occur during the heating of samples until 1000 degree centigree, Determinations of heat content at each temperature were made using an isoperibol calorimeter. The mean specific heat was calculated from these values, and its dependence on temperature was determined. The maximum weight loss was about 32.5% and the specific heat obtained was 1,13 kJ/kg 0 C for solid samples and 1,38 kJ/kg''0 C for fluid samples. The results are useful for the design of the industrial process, in order to determine the thermal requirements for heating calcined ulexite, and to obtain smelted ulexite. (Author) 19 refs.

Energy Technology Data Exchange (ETDEWEB)

The information reported is for the period October I to December 31, 1993. During this quarter, activities were undertaken in Task 2. Oxygen concentrations were measured in the post-flame region of the entrained flow reactor. The sampling probe was used for the hot gas tests to sample the gas stream. Samples were injected into a gas chromatograph to determine the oxygen concentration. Results agreed with thermoequilibrium calculations that yield equilibrium compositions based on the stoichiometry of the feed gases. The axial temperature distribution along the reactor centerline was measured using a silica-coated platinum-rhodium thermocouple. Two coating techniques were tested and it was found that flame-plating silica to the thermocouple wires produced a thinner coating than a ceramic adhesive technique and therefore a smaller radiation correction. Other activities this quarter included the fabrication ...

Energy Technology Data Exchange (ETDEWEB)

We have developed an ion probe technique for the in situ measurement of oxygen isotope ratios, {sup 18}O/{sup 16}O and {sup 17}O/{sup 16}O, with high spatial resolution in polished thin sections of silicate minerals. This technique allows the isotopic analysis of samples as small as picomoles of material which represents only 10{sup -7} of the sample size required by conventional fluorination oxygen isotope measurement methods and thus has wide application to the study of many terrestrial and extra-terrestrial samples that have heterogeneous oxygen isotope compositions on a scale of tens of micrometres. To illustrate the breadth of studies that are made possible by the ion probe, we report here oxygen isotope measurements from an authigenic quartz overgrowth obtained from the Penrith sandstone, UK, and measurements of magnetite grains from the Orgueil and Yamato 82162 carbonaceous chondrites which may ...

International Nuclear Information System (INIS)

An energy analyzer has been constructed and operated in UHV for the purpose of analyzing the energy of neutral atoms scattered from solid surfaces. The analyzer consists of a LiF single crystal located at an angle close to the normal to the sample crystal so that the diffraction pattern obtained by scanning the LiF crystal yields the energy of the scattered atoms. Two designs which have been used are described. The temperature of both sample and analyzer crystal is near 20 K and once cleaned they can be maintained in the state of initial preparation for many weeks. The sample was a (001) Cu surface in this case. Such an energy analyzer can only be used, in most cases, for He atom scattering although Ne atoms could be used if the scattered intensities were adequate. The detector developed in this study is able to detect about 2 x 10"5 atoms/s. The resolution of the spectrometer depends on the incident energy of the atom and ...

Energy Technology Data Exchange (ETDEWEB)

Survival curves were constructed from dose-incidence curves for apoptosis in the crypts of mouse small intestine, using the number of apoptotic cells after high doses (N{sub M}) as maximum cell population size. The mean lethal doses (D{sub 0}) for the dose range 0-0.5 Gy were calculated for each time of day. A circadian rhythm in both D{sub 0} and N{sub M} values was detected, indicating that both the number and sensitivity of radiation-induced apoptosis were changing throughout the day. (author).

Energy Technology Data Exchange (ETDEWEB)

Procedures followed in designing for offshore production rigs in the Northeastern Areas of the Campos Basin are presented. Various advantages afforded by the mast in the performance of required tasks are analyzed, along with all calculation premises and methods for adequate sizing. Standards covering mast design, materials used in manufacture, and test routines are also examined. (author). 16 figs., 3 tabs., 11 refs

International Nuclear Information System (INIS)

The distributions of the effective numbers of 6q-fluctons in the energy, momentum and distance to the center of mass of nucleus are studied. Many characteristics of these distributions are shown to be universal, i.e. independent of the flucton size. The saturation of the flucton density in A > 80 nuclei and other peculiarities are found, which define different behavior of the effective numbers of fluctons and deuterons. This fact provides an explanation of the known underestimate by a factor of 1.5-6 of the cross sections of hard inclusive (p, p'd) process on nuclei calculated in the quasi-elastic approximation.

Science.gov (United States)

Visual Sample Plan (VSP) is an easy-to-use visual and graphic statistically-based software tool being developed by the Pacific Northwest National Laboratory (PNNL) to help determine the appropriate number and location of environmental samples so that environmental decisions can be made with the required confidence. The VSP software, which is available free at http://dqo.pnl.gov/vsp, is a significant aid in developing probability-based sampling designs (number and location of samples and measurements) using the Data Quality Objectives (DQO) planning process developed by the U.S. Environmental Protection Agency (EPA). VSP also has the capability of conducted statistical analyses to provide descriptive statistical summaries of data sets, to test whether data are normally distributed, and to compute upper confidence limits on means. This report is the latest in a series of reports that document the ...

International Nuclear Information System (INIS)

We report ab initio calculations of positron wave functions in the high-T/sub c/ superconductors YBa_2Cu_3O_7, Bi_2Sr_2CaCu_2O_8, and Tl_2Ba_2CaCu_2O_8 using the general potential linearized augmented plane-wave method. The calculated positron wave functions are fairly insensitive to whether or not electron-positron correlation is included in the calculation for YBa_2Cu_3O_7 and Tl_2Ba_2CaCu_2O_8, but the calculated positron density is quite sensitive to correlation in Bi_2Sr_2CaCu_2O_8. While the positron wave function samples primarily the chain region in YBa_2Cu_3O_7, the results indicate that positrons should be good probes of the Cu-O layer-derived electronic states near the Fermi energy in Tl_2Ba_2CaCu_2O_8 since a large overlap with these states is predicted.

Energy Technology Data Exchange (ETDEWEB)

The microstructure evolution of nine samples from three Ir-base ternary systems, Ir-Nb-Hf, Ir-Nb-Ta, and Ir-Nb-Ti, was investigated by microstructure observation using scanning electron microscopy (SEM), composition map-analysis using electron probe microscopy analysis (EPMA), and phase determination using X-ray diffraction (XRD) patterns. The fcc/L1{sub 2} two-phase structure was detected in all the samples. Lattice misfits between fcc and L1{sub 2} phases were calculated. Ir-Nb-Ta and Ir-Nb-Ti alloys exhibited a microstructure quite similar to that of Ni-base superalloys, and the cuboidal L1{sub 2} precipitates in Ir-Nb-Ta and Ir-Nb-Ti alloys could maintain up to 1900 {sup o}C.

British Library Electronic Table of Contents (United Kingdom)

Abstract Here we propose a software for the estimation of the occupied area and volume of fungal cultures. This software was developed using a Matlab platform and allows analysis of high-definition images from optical, electronic or atomic force microscopes. In a first step, a single hypha grown on potato dextrose agar was monitored using optical microscopy to estimate the change in occupied area and volume. Weight measurements were carried out to compare them with the estimated volume, revealing a slight difference of less than 1.5%. Similarly, samples from two different solid-state fermentation cultures were analyzed using images from a scanning electron microscope (SEM) and an environmental SEM (ESEM). Occupied area and volume were calculated for both samples, and the results obtained w...

Energy Technology Data Exchange (ETDEWEB)

The black carbon continuum is composed of a series of carbon-rich components derived from combustion or metamorphism and characterized by contrasting environmental behavior and susceptibility to oxidation. In this work, we present a micro-scale density fractionation method that allows isolating the small quantities of soot-like and graphitic material usually found in natural samples. Organic carbon and {delta}{sup 13}C mass balance calculations were used to quantify the relative contributions of the two fractions to thermally-stable organic matter from a series of aquatic sediments. Varying proportions of soot-like and graphitic material were found in these samples, with large variations in {delta}{sup 13}C signatures suggesting important differences in their origin and/or dynamics in the environment.

International Nuclear Information System (INIS)

Monte Carlo simulation of beam modifiers such as physical wedges and compensating filters has been performed with a rectilinear voxel geometry module. A modified version of the EGS4/DOSXYZ code has been developed for this purpose. The new implementations have been validated against the BEAM Monte Carlo code using its standard component modules (CMs) in several geometrical conditions. No significant disagreements were found within the statistical errors of 0.5% for photons and 2% for electrons. The clinical applicability and flexibility of the new version of the code has been assessed through an extensive verification versus dosimetric data. Both Varian multi-leaf collimator (MLC) wedges and standard wedges have been simulated and compared against experiments for 6 MV photon beams and different field sizes. Good agreement was found between calculated and measured depth doses and lateral dose profiles along both wedged and unwedged directions for ...

Energy Technology Data Exchange (ETDEWEB)

In this study, nanoparticle penetration was measured with a wide range of filter media using silver nanoparticles from 3 nm to 20 nm at three different face velocities in order to define nanoparticle filtration characteristics of commercial fibrous filter media. The silver particles were generated by heating a pure silver powder source via an electric furnace with a temperature of 870 deg. C, which was found to be the optimal temperature for generating an adequate amount of silver nanoparticles for the size range specified above. After size classification using a nano-DMA, the particle counts were measured by an Ultrafine Condensation Particle Counter (UCPC) both upstream and downstream of the test filter to determine the nanoparticle penetration for each specific particle size. Particle sampling time continued long enough to detect more than 10{sup 5} counts at the upstream and 10 counts at the ...

International Nuclear Information System (INIS)

This paper first introduces the calculating method of radium specific activity to determine the radon emanation rate of tailing of uranium mine No. 794, the method needs two parameters: radon emanation coefficient and radon diffusion coefficient. According to the measured results of parameters and the contrast between radium specific activity of indoor chemical analysis of field sample and field gamma-ray spectra, the authors discuss the variation rules and characteristics of radon emanation coefficient and radon diffusion coefficient, and the best climate and seasons for measuring these parameters in northern China, and finally summarize the characteristics of this method through analyzing measured results. (authors)

Energy Technology Data Exchange (ETDEWEB)

Ab initio planewave pseudopotential method is used to study carbon diffusion and pairing in crystalline silicon. The calculation is performed with a 40 Ry planewave cutoff and 2x2x2 special k-point sampling with a supercell of 64 atoms. It is found that substitutional carbon attracts interstitial Si forming a <001> C interstitial with a large binding energy of 1.45 eV. The interstitial carbon is mobile and can migrate with a migration energy of 0.5 eV. The interstitial carbon can bind further to another substitutional carbon forming a substitutional carbon-interstitutional carbon pair with a binding energy of 1.0 eV. This model is used to understand the effect of high C concentration on the transient enhanced diffusion in Si.

Science.gov (United States)

Under different sintering temperatures(340 degrees C, 440 degrees C, 540 degrees C, 640 degrees C), four TiO2 particles were prepared. The crystal types of all four samples were found to possess anatase structures by XRD. It was obtained by N2 experimental adsorption at low temperature (77K) that their surface areas and average pore size were between 79 and 124 m2/g, 56.8 and 254.8 A respectively. The pore structure of TiO2 particles was characterized by scanning electron microscope (SEM). The tests of adsorption dynamics for FGD and the performance of SO2 removal were investigated in a fixed-bed system for different samples. The results show that SG540 sample which made at 540 degrees C sintering temperature had the most quality among the four samples. It can adsorb SO2 of 38.9 mg for one gram SG540 sample. Different operating conditions for SG540 such as ...

International Nuclear Information System (INIS)

The nanocrystallization process of amorphous Fe_7_3_._5Si_1_3_._5B_9Nb_3Cu_1 was investigated by active screen plasma nitriding (ASPN) treatment at temperatures ranging from 410 "oC to 560 "oC for 3 h in two gas mixtures of 75% N_2-25% H_2 and 25% N_2-75% H_2 at 5 mbar atmosphere. The amorphous ribbons were then annealed under vacuum at the same time and temperatures mentioned above. The structure of the samples was analyzed using various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). Microhardness measurements, electrical resistivity and Vibrating Sample Magnetometer (VSM) were used to study mechanical, electrical and magnetic properties of the samples, respectively. It was observed that the ASPN treatment leads to finer grain size and higher crystalline volume fraction and modifies the structural features of Fe(Si) phase. The ...

Energy Technology Data Exchange (ETDEWEB)

Sulfuric acid and its partially or completely neutralized salts with ammonia are believed to result from the oxidation of sulfur dioxide in cloud water and in other heterogeneous media present in the atmosphere. Due to the natural abundance of ammonia and the ubiquitous presence of sulfur in the atmosphere, (NH/sub 4/)/sub 2/SO/sub 4/ is commonly the dominant chemical species in the ambient aerosol. The amounts of ammonium sulfates are expected to be very low in areas far removed from anthropogenic emissions of sulfur dioxide. The chemical composition of submicrometer aerosol particles was determined at the Mauna Loa Observatory (MLO) on Mauna Loa in Hawaii during an eight-day period in August 1986. The MLO site was selected for this measurement because it is the only ground-based aerosol observatory in the remote Pacific Ocean that allows extended sampling of aerosols in the free troposphere. Measurements were made using an attenuated total internal reflection ...

Energy Technology Data Exchange (ETDEWEB)

Testing two or more data sets for the hypothesis that they are sampled form the same population is often required in environmental data analysis. Typically the available samples have a small number of data and often then assumption of normal distributions is not realistic. On the other hand the diffusion of the days powerful Personal Computers opens new possible opportunities based on a massive use of the CPU resources. The paper reviews the problem introducing the feasibility of two non parametric approaches based on intrinsic equi probability properties of the data samples. The first one is based on a full re sampling while the second is based on a bootstrap approach. A easy to use program is presented. A case study is given based on the Chernobyl children contamination data. [Italiano] Nell`analisi di dati ambientali ricorre spesso il caso di dover sottoporre a test l`ipotesi di provenienza di due, o ...

Energy Technology Data Exchange (ETDEWEB)

A 100 kW thermal input Two-Stage Gasifier was built at the University of Denmark (DTU). The gasifier consists of an externally heated pyrolysis unit, a down-draft char gasifier, a gas cleaning system and an internal-combustion engine. Between the summer of 1996 and the summer of 1998, 11 tests were made with the gasifier. The gasifier had a total operating time of 278 hours (excluding warming up). The fuel was mainly wood chips, but also briquettes has been used. Four of the tests lasted 50-70 hours, and stable conditions were reached. All the tests were completed without technical problems. The particle sizes and amounts were investigated. The amount of particles depended on the amount of steam led to the gasifier. More than 99% of the particles after the cyclone were soot. The size of the soot particles was mainly between 0.2-0.5 {mu}m. Under normal conditions (biomass:steam = 1:1 (dry mass basis)), the particle load was about 300 mg/Nm{sup ...

International Nuclear Information System (INIS)

In this paper a computational analysis of 11 fuel samples (seven UO_2 and four MOX) with a burn-up ranging from 20 MWd/kgHM up to 121 MWd/kgHM (HM: Heavy Metal) is carried out with the depletion module of the lattice code CASMO-4E [Rhod01, Rhod01b] using the neutron data libraries ENDF/B-VI and JEF-2.2 and a pin cell model. In order to assess the accuracy of the model and the depletion calculation in the determination of the isotopic inventory after several irradiation cycles, the calculated results were compared to experimental data gathered from a chemical isotopic analysis of the fuel samples performed at the Hot Laboratory at the Paul Scherrer Institut (PSI), Switzerland. Selected results of this comparison, which includes 54 isotopes (17 actinides and 37 fission products), are presented here. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The automatic interpretation of apparent resistivity curves from horizontally layered earth models is carried out by the curve-fitting method in three steps: (1) the observed VES data are interpolated at equidistant points of electrode separations on the logarithmic scale by using the cubic spline function, (2) the layer parameters which are resistivities and depths are predicted from the sampled apparent resistivity values by SALS system program and (3) the theoretical VES curves from the models are calculated by Ghosh's linear filter method using the Zhody's computer program. Two soundings taken over Takenoyu geothermal area were chosen to test the procedures of the automatic interpretation.

International Nuclear Information System (INIS)

The crystallite size and orientation in molybdenum films prepared by magnetron sputtering at a low rate of typical 1 (angstrom)s and a pressure of 0.45 Pa was investigated by X-ray diffraction and texture analysis. The surface topography was studied using atomic force microscopy. Increasing the film thickness from 20 nm to 3 microm, the films show a turnover from a (110) fiber texture to a (211) mosaic-like texture. In the early state of growth (20 nm thickness) the development of dome-like structures on the surface is observed. The number of these structures increases with film thickness, whereas their size is weakly influenced. The effect of texture turnover is reduced by increasing the deposition rate by a factor of six, and it is absent for samples mounted above the center of the magnetron source. The effect of texture turnover is related to the bombardment of the films with high energetic argon neutrals resulting from ...

British Library Electronic Table of Contents (United Kingdom)

Ultra fine tungsten carbide and cobalt powders were milled by high energy planetary ball mill at different ball to powder weight ratios (BPR) to produce particles of WC-10wt%Co hard metal in nanometer scale size. Microstructural characterizations by TEM show that the particle size of tungsten carbide was achieved to 32nm after milling at 15 BPR during 10h. In order to reduce the WC grain growth during the sintering process, tantalum carbide was added to the hard metal as a WC grain growth inhibitor. The nano hard metal powders were compacted at 200MPa pressure and sintered at 1370-1450degreeC temperatures in a high purity hydrogen atmosphere. The results show that the addition of 0.6wt% of TaC improves the hardness and fracture toughness from 1493 HV30 and 11.8MPam (for TaC free sample) to...

Energy Technology Data Exchange (ETDEWEB)

Silicon nitride based ceramics have attracted considerable attention as good candidates for structural applications due to their excellent mechanical properties including strength, hardness, fracture toughness, and high temperature strength. These properties are strongly influenced by grain size and morphology, and by the degree of crystallinity and chemistry of grain boundary phases. In this work, the microstructure of Si{sub 3}N{sub 4} densified with Nd{sub 2}O{sub 3}, Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3} sintering additives was studied. Sintered samples were polished and plasma etched for microstructural analysis using scanning electron microscope. Quantitative evaluation of materials microstructure was accomplished using Quantikov software. Fracture toughness was measured by Vickers indentation method. The observed microstructure is typical of silicon nitride based materials and is characterized by high aspect ratio.-Si{sub 3}N{sub 4} ...

Science.gov (United States)

The relationship between processing, microstructure, and properties was studied for A-15 compounds in multifilamentary composites produced by solid-state diffusion and in thin-film samples produced by vapor deposition. Grain sizes of A-15 superconducting compounds were measured by transmission electron microscopy of multifilamentary composites reacted at various temperatures. Critical current densities at 4.2 K and fields up to 6 T were found to be similar for niobium-tin, vanadium-gallium, and vanadium-silicon of the same grain size. Study of the Cu-V-Si phase diagram led to the production of improved multifilamentary vanadium-silicon conductors. The effects of various alloying elements on A-15 layers produced by solid-state diffusion were studied. The most promising new observation was that tantalum can be incorporated into niobium-tin reaction layers, leading to an enhancement of critical currents at high fields. The ...

Science.gov (United States)

Two major modes of CO adsorption on SiO{sub 2}-supported Pd reflect different extents of back-donation, which is, at least in part, controlled by the local electron density at the adsorption site. The fraction of CO in the bridging mode (B) increases and that of the linear mode (L) decreases, with increasing size of the Pd particles, indicating high electron density at Pd atoms in terraces of close-packed crystal faces, in agreement with Smoluchowski's classical model. For samples reduced at 300{degree}C our data points and those of other authors are located on a common curve of B/L vs metal dispersion. Extensive reduction at 600{degree}C results in significantly lower B/L values, attributed to the incipient formation of a palladium silicide. Oxidation followed by reduction at 300{degree}C destroys the silicide, and the B/L value returns to the original curve.

International Nuclear Information System (INIS)

Holmium doped barium based hexaferrites BaFe_1_2_-_2_xHo_2_xO_1_9 with (x = 0.0-1.0) were synthesized by solid state reaction method. Structural and magnetic characterization of these ferrites provide significant information about their reactive physical properties. X-ray analysis reveals that in all samples M-type structure exist with few secondary phases. Scanning electron microscope revealed the grain size of the specimen. The results show that grain size decreases with the substitution degree of Holmium. Thus rare earth element Holmium Ho"3"+ acts as a grain growth inhibitor. The magnetic hysteresis loops show the variation in the values of magnetic parameters like saturation magnetization (M_s), remanent magnetization (M_r) and coercivity (H_c) were observed by changing Ho"3"+ content in BaFe_1_2_-_2_xHo_2_xO_1_9 ferrites. Coercivity showed a maximum value of 2230 Oe for (x = 0.4) and then decreasing trend were ...

International Nuclear Information System (INIS)

As part of the national survey to evaluate natural radioactivity in the environment, concentration levels of natural uranium and "2"2"6Ra have been analyzed in over 300 drinking water samples taken from different locations in Argentina. "2"2"6Ra was determined by "2"2"2Rn emanation and liquid scintillation counting, and natural uranium by a fluorimetric procedure. Values ranging from 0.03 to 24 #mu#g.l"-"1 of natural uranium and from 0.06 to 50 #mu#g.l"-"1, were measured on drinking water samples taken from tap water systems and private wells, respectively. Concentrations up to 15 mBq.l"-"1 and to 22 mBq.l"-"1 of "2"2"6Ra were found in drinking water samples taken from tap water systems and private wells, respectively. These values are compared with the reference values accepted for drinking water. Based on the water intake rate, the age distribution and the measured concentrations, an annual collective effective dose of ...

Energy Technology Data Exchange (ETDEWEB)

As part of the demonstration testing of the Purge Water Management System (PWMS) technology at the Savannah River Site (SRS), four wells were equipped with PWMS units in 1997 and a series of sampling events were conducted at each during 1997-1998. Three of the wells were located in A/M Area while the fourth was located at the Old Radioactive Waste Burial Ground in the General Separations Area.The PWMS is a ''closed-loop'', non-contact, system used to collect and return purge water to the originating aquifer after a sampling event without having significantly altered the water quality. One of the primary concerns as to its applicability at SRS, and elsewhere, is whether the PWMS might resample groundwater that is returned to the aquifer during the previous sampling event. The purpose of the present investigation was to compare groundwater chemical analysis data collected at the four test ...

Energy Technology Data Exchange (ETDEWEB)

To help confirm correct functioning of an epithermal neutron sonde, we measured tightly bonded water content of selected Nevada Test Site (NTS) drill holes. Tuff and alluvium samples were dried overnight at 105/sup 0/C. The samples were then heated for 45 min in a split tube furnace at 700/sup 0/C. The water that came off due to this heating was collected and the amount recorded. The error in this procedure is +- 0.59 wt %. Total water can be calculated for samples from analyses of free and tightly bonded water contents. The maximum error in this calculation is equivalent to the error in determining the more tightly bonded water. Average total water content values have been assigned to geologic units. These values, in weight fraction, are alluvium 0.14 +- .05 and tuff 0.19 +- .04. Further division of the tuff gives values of Rainier Mesa 0.15 +- .01, Paintbrush 0.18 +- .03, Tunnel ...

International Nuclear Information System (INIS)

Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) has been proposed several years ago as an approach for quantitative analysis of Laser-Induced Breakdown Spectroscopy spectra. Recently developed refinement of the spectral processing method is described in the present work. Accurate quantitative results have been demonstrated for several metallic alloys. However, the degree of accuracy that can be achieved with Calibration-Free Laser-Induced Breakdown Spectroscopy analysis of generic samples still needs to be thoroughly investigated. The authors have undertaken a systematic study of errors and biasing factors affecting the calculation in the Calibration-Free Laser-Induced Breakdown Spectroscopy spectra processing. These factors may be classified in three main groups: 1) experimental aberrations (intensity fluctuations and inaccuracy in the correction for spectral efficiency of a detection system), 2) inaccuracy in theoretical ...

British Library Electronic Table of Contents (United Kingdom)

Diet overlap and niche breadth are well-known species traits from trophic ecology that can assist in explaining how species interact and coexist as well as the ecological mechanisms that influence biodiversity. In the present study, we analyzed the relationships between these trophic variables and indicators of resource availability with some attributes of fish assemblages (species richness, Shannon diversity index, evenness, density and individual body size). The physical and chemical characteristics of the biotopes (topography, water quality and conservation of slopes) were examined to identify possible patterns. Monthly sampling using electrofishing was conducted in 2003 along five streams located in the Cuiab? River watershed. The relationships between environmental variables and attri...

International Nuclear Information System (INIS)

In this paper a novel method is presented, based on the use of plasma processing, to suppress the transient enhanced diffusion of boron implanted in silicon. We found for silicon samples processed with plasma and subsequently boron implanted that the anomalous diffusion of the dopant atoms at the beginning of the annealing process is almost completely suppressed. This phenomenon is interpreted in terms of capture of the ion beam generated interstitials by the dislocations induced by the plasma processing. At room temperature the dislocations are observed to grow in size after the boron implant, attesting their efficiency as trapping centres for interstitials. Moreover, varying the plasma process conditions we can establish a general relation between the presence of the trapping centres induced by the plasma processing and the suppression of the transient diffusion.

Science.gov (United States)

The use of meta-analysis has become increasingly useful for clinical and policy decision making. A recent development in meta-analysis, multiple treatment comparison (MTC) meta-analysis, provides inferences on the comparative effectiveness of interventions that may have never been directly evaluated in clinical trials. This new approach may be confusing for clinicians and methodologists and raises specific challenges relevant to certain areas of medicine. This article addresses the methodological concepts of MTC meta-analysis, including issues of heterogeneity, choice of model, and adequacy of sample sizes. We address domain-specific challenges relevant to disciplines of medicine, including baseline risks of patient populations. We conclude that MTC meta-analysis is a useful tool in the context of comparative effectiveness and requires further study, as its utility and transparency will likely predict its uptake by the research and clinical ...

CERN Document Server

In order to reduce the activation temperature of the TiZrV alloy, thin films of various compositions were produced by three-cathode magnetron sputtering on stainless-steel substrates. For the characterisation of the activation behaviour the surface chemical composition has been monitored by Auger electron spectroscopy during specific in situ thermal cycles. The volume elemental composition of the film has been measured by energy dispersive X-ray spectroscopy and the morphology (crystal structure and size of the crystallites) has been investigated by X-ray diffraction. The criteria indicating the sample quality and its dependence on film structure and chemical composition are presented and discussed. (13 refs).

International Nuclear Information System (INIS)

High-resolution electron microscope observations confirm the presence of small crystallites in thin TbFeCo films protected by Si_3N_4 overcoats. Selected area electron diffraction patterns in top-view projection indicate that the crystals have a face-centered-cubic structure. Microscope analysis reveals grain growth following annealing of these protected thin films at 200 degree C in vacuum, and Kerr measurements yield large reductions in coercivity relative to the room-temperature value. The typical grain size visible in top-view observations increases from about 3 nm in the as-deposited samples to about 30 nm after annealing at 200 degree C for 36 h while the static coercivity, H_c, drops by about 40%. The fcc structure of the crystals is retained after annealing.

British Library Electronic Table of Contents (United Kingdom)

Abstract The recent paper by Heyer et al. indicates that observations of size, linewidth and column density of interstellar clouds do not agree with simple virial equilibrium (SVE) as a balance between gravitational and kinetic energies in the sense that the clouds either have too much kinetic energy or too little mass to be bound. This may be explained by violation of SVE as suggested by Dobbs et al., by observational underestimation of the masses as suggested by Heyer et al. or by an external pressure acting as an additional confining force as suggested earlier by Heyer et al. The data of Heyer et al. cannot be explained with a single value for the external pressure, but if different clouds in the sample have different external pressures in the range of Pe/k= 104-107 cm-3-K, then most of...

International Nuclear Information System (INIS)

Nowadays, diamond and the nitrogen-vacancy (NV) colour centres constitute the best solid-state system in view of quantum-computing applications. It has also been shown recently that single NV centres could be used as nanoscale magnetic sensors. Such applications require the creation of single NV centres with very high resolution and with a high efficiency. The nano-implanter at the university of Bochum provides low energy nitrogen ions which can be implanted through a hole pierced in the tip of an atomic force microscope. Ultrapure diamond samples have been implanted with spot sizes of 50nm and less. Stimulated Emission Depletion (STED) microscopy has been used to characterise and resolve the implanted spots.

International Nuclear Information System (INIS)

The thermal recovery of superconducting elements working as secondaries in fault current limiters can be enhanced by taking advantage of the removal of heat by conduction from an array of artificial weak zones (AWZ) distributed along the superconductor perimeter (hot parts) to the non-weak segments (cold parts). These results were obtained by studying samples with weak parts in the shape of grooves, all identical in size. In this paper we consider the case in which one of the AWZ is slightly different from the rest. Our results show that a change in its length has a negligible effect. On the contrary, a groove which is slightly deeper can be overheated and hence can strongly determine the recovery time of the whole limiter.

British Library Electronic Table of Contents (United Kingdom)

Coal mining activities cause an increased acidity and an associated decrease of the pH-value in mine waters. This process is also known as acid mine drainage (AMD). Due to AMD, lakes that were formed in the post mining landscapes in the lignite mining area of Central Germany are characterized by specific limnological development changes. Remote sensing is a time and cost saving technique that enables the observation of the hydrological and limnological development of the lakes ranging from a small to a mid size scale. The current research was based on Landsat TM5/ETM+7 satellite data collected between 1999 and 2004. In combination of satellite data, surface waters of the post mining lakes in Central Germany were sampled and analyzed for their physicochemical properties. The objective of th...

International Nuclear Information System (INIS)

Numerous mercury intrusion porosimetry (MIP) studies have been carried out to investigate the pore structure in cement-based materials. However, the standard MIP often results in an underestimation of large pores and an overestimation of small pores because of its intrinsic limitation. In this paper, an innovative MIP method is developed in order to provide a more accurate estimation of pore size distribution. The new MIP measurements are conducted following a unique mercury intrusion procedure, in which the applied pressure is increased from the minimum to the maximum by repeating pressurization-depressurization cycles instead of a continuous pressurization followed by a continuous depressurization. Accordingly, this method is called pressurization-depressurization cycling MIP (PDC-MIP). By following the PDC-MIP testing sequence, the volumes of the throat pores and the corresponding ink-bottle pores can be determined at every pore size. These ...

Energy Technology Data Exchange (ETDEWEB)

For the first time, rheological phase method, a simple and effective route, is applied to synthesize novel cathode material LiCoPO{sub 4}. X-ray diffraction spectrometer (XRD), X-ray photoelectron spectrometer (XPS), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS) are taken to investigate this material, respectively. XRD figure shows that the rheological sample is better crystallized than the solid-state one. XPS result of the rheological sample exhibits that the valence of Co is 2+. TEM images show that better dispersed particles with smaller size can be formed by rheological method comparing to the solid-state route. Charge-discharge test is carried out in the range of 3.0-5.0 V at 0.2 mA cm{sup -2}. The initial discharge capacity for rheological phase and solid-state powder is 71.5 and 30.9 mAh g{sup -1}, respectively. The better electrochemical property should be ascribed to the ...

Energy Technology Data Exchange (ETDEWEB)

The objective of the Coastal Habitat Injury Assessment study was to document and quantify injury to biota of the shallow subtidal, intertidal, and supratidal zones throughout the shoreline affected by oil or cleanup activity associated with the Exxon Valdez oil spill. The results of these studies were to be used to support the Trustee`s Type B Natural Resource Damage Assessment under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). A probability based stratified random sample of shoreline segments was selected with probability proportional to size from each of 15 strata (5 habitat types crossed with 3 levels of potential oil impact) based on those data available in July, 1989. Three study regions were used: Prince William Sound, Cook Inlet/Kenai Peninsula, and Kodiak/Alaska Peninsula. A Geographic Information System was utilized to combine oiling and habitat data and to select the probability ...

Energy Technology Data Exchange (ETDEWEB)

A relatively quick and simple assay for hyaluronate was developed using the specific binding protein, hyaluronectin. The hyaluronectin was obtained by homogenizing the brains of Sprague-Dawley rats, and then centrifuging the homogenate. The resulting supernatant was used as a source of crude hyaluronectin. In the binding assay, the hyaluronectin was mixed with (/sup 3/H)hyaluronate, followed by an equal volume of saturated (NH/sub 4/)/sub 2/SO/sub 4/, which precipitated the hyaluronectin and any (/sup 3/H)hyaluronate associated with it, but left free (/sup 3/H)hyaluronate in solution. The mixture was then centrifuged, and the amount of bound (/sup 3/H)hyaluronate in the precipitate was determined. Using this assay, the authors found that hyaluronectin specifically bound hyaluronate, since other glycosaminoglycans failed to compete for the binding protein. In addition, the interaction between hyaluronectin and hyaluronate was of relatively high affinity, and the ...

International Nuclear Information System (INIS)

Measurements of ion-induced electron emission have been performed with helium and argon ions with energies between 300 and 900 eV on W, W with 10% Ti, Al, Al with 1% Cu, Al with 1% Si, Si, and Be. This article describes many of the important surface characteristics that influence the ion-induced electron emission. For low-energy ions, the substrate material was found to be less important as the velocity of the incident ion decreased. In the case of incident Ar"+ the substrate material had a negligible effect on the emission for this energy range. The presence of an adsorbed layer enhanced emission in all cases. Heating the substrates resulted in oxidation of the surfaces and a subsequent increase in emission. The electron emission from aluminum samples with smaller grain sizes was higher than samples of identical composition with larger grains. This effect is due to the greater number of adsorption sites resulting from the ...

CERN Document Server

We present new low resolution Spitzer mid-infrared spectroscopy of a sample of 20 ROSAT selected local Narrow Line Seyfert 1 galaxies (NLS1s). We detect strong AGN continuum in all and clear PAH emission in 70% of the sources. The 6.2 micron PAH luminosity spans three orders of magnitudes, from ~10^(39) erg/s to ~10^(42) erg/s providing strong evidence for intense ongoing star formation in the circumnuclear regions of these sources. Using the IRS/Spitzer archive we gather a large number of additional NLS1s and their broad line counterparts (BLS1s) and constructed NLS1 and BLS1 sub-samples to compare them in various ways. The comparison shows a clear separation according to FWHM(H_beta) such that objects with narrower broad H_beta lines are the strongest PAH emitters. We test this division in various ways trying to remove biases due to luminosity and aperture size. Specifically, we find that star formation activity around ...

Energy Technology Data Exchange (ETDEWEB)

Radon exposure assessment in case-control studies on radon and lung cancer is generally based on contemporary radon concentration measurements, which can be affected by significant changes in the building structures or in living habits. Another method to estimate the radon exposure of the subjects is the recently developed retrospective dosimetry technique based on the {sup 210}Po surface activity from glass objects. In order to compare the results obtained by the two methods, a study has been carried out in a sample of 26 dwellings in Rome, with radon concentration values ranging from 28 to 623 Bq m{sup -3}. Retrospective detectors based on CR-39 and LR 115 were exposed on 50 glass objects in bedrooms and living rooms. The correlation factor between the two sets of data, after removing six extreme values, is 0.67, which is similar to results obtained in other validation studies of similar sample size. The correlation ...

International Nuclear Information System (INIS)

Many types of pipe whip restraints are installed to protect the structural components from the anticipated pipe whip phenomena of high energy lines in nuclear power plants. It is necessary to investigate these phenomena accurately in order to evaluate the acceptability of the pipe whip restraint design. Various research programs have been conducted in many countries to develop analytical methods and to verify the validity of the methods. In this study, various calculational models in ANSYS code and in ADLPIPE code, the general purpose finite element computer programs, were used to simulate the postulated pipe whips to obtain impact loads and the calculated results were compared with the specific experimental results from the sample pipe whip test for the U-shaped pipe whip restraints. Some calculational models, having the spring element between the pipe whip restraint and the pipe line, give reasonably ...

Science.gov (United States)

In March 2007 in-pile testing of LEU U-Mo full-size IRT type fuel elements was started in the MIR reactor. Four prototype fuel elements for Uzbekistan WWR SM reactor are being tested simultaneously - two of tube type design and two of pin type design. The dismountable irradiation devices were constructed for intermediate reloading and inspection of fuel elements during reactor testing. The objective of the test is to obtain the experimental results for determination of more reliable design and licensing fuel elements for conversion of the WWR SM reactor. The heat power of fuel elements is measured on-line by thermal balance method. The distribution of fission density and burn-up of uranium in the volume of elements are calculated by using the MIR reactor MCU code (Monte-Carlo) model. In this paper the design of fuel elements, the technique, main parameters and preliminary results are described. (author)

Energy Technology Data Exchange (ETDEWEB)

With regard to the elastic wave exploration, discussions have been given on the relationship between frequency and resolution in P-wave velocity tomography using the initial travel time. The discussions were carried out by using a new analysis method which incorporates the concept of Fresnel volume into tomography analysis. The following two arrangements were used in the calculation: a cross hole arrangement, in which seismic source and vibration receiving points were arranged so as to surround the three directions of a region extending 250 m in the horizontal direction and 500 m in the vertical direction, and observation is performed between two wells, and a permeation VSP arrangement in which the seismic source is installed on the ground surface and receiving points installed in wells. Restructuring was performed on the velocity structure by using a total of 819 observation travel times. This method has derived results of the restructuring according to ...

Energy Technology Data Exchange (ETDEWEB)

Numerical studies are performed to identify an optimal range of geometric parameters in connection with the design of an impingement-conditioned small direct-injection diesel engine. The parametric studies were made in a pressure chamber with a circular protrusion on to which sprays are directed to impinge. Computational runs were made for 24 cases carefully chosen to allow examination of the effects on post-impingement spray characteristics of the following parameters: (a) the nozzle-plate distance and (b) the size and geometry pattern of the protrusion. An optimal range of these parameters has been identified through an analysis of the calculated results in terms of vapour concentration, the Sauter mean diameter of the wall spray and the dispersed wall spray volume. The results obtained also reveals that, by just changing the size of the impingement surface and the impingement distance, local fuel vaporization efficiency ...

CERN Document Server

We describe a new concept for a MEMS-based active spatial filter for astronomical spectroscopy. The goal of this device is to allow the use of a diffraction-limited spectrometer on a seeing limited observation at improved throughput over a comparable seeing-limited spectrometer, thus reducing the size and cost of the spectrometer by a factor proportional to r0/D (For the case of a 10 meter telescope this size reduction will be approximately a factor of 25 to 50). We use a fiber-based integral field unit (IFU) that incorporates an active MEMS mirror array to feed an astronomical spectrograph. A fast camera is used in parallel to sense speckle images at a spatial resolution of lambda/D and at a temporal frequency greater than that of atmospheric fluctuations. The MEMS mirror-array is used as an active shutter to feed speckle images above a preset intensity threshold to the spectrometer, thereby increasing the signal-to-noise ratio (SNR) of the ...

Science.gov (United States)

The MgF{sub 2} monocrystals were irradiated at room temperature with 390 keV B{sup +} ions up to the fluence of 10{sup 16} cm{sup -2}. The irradiated samples were (isochronally and isothermally) annealed in high vacuum at the temperatures 200 deg. C, 300 deg. C, 400 deg. C, 500 deg. C, 600 deg. C and 700 deg. C for the times ranging from 2-100 hours. After each annealing step, the boron depth distribution was determined using the neutron depth profiling technique. As implanted, the depth distributions of boron exhibited standard Gaussian-like forms, but the evaluated profile parameters, R{sub P} = 960 nm and {delta}R{sub P} = 140 nm, were higher than those calculated using the SRIM code (R{sub P} = 870 nm and {delta}R{sub P} = 115 nm). Annealing at temperatures up to 400 deg. C did not change the depth profiles. Annealing at 600 deg. C, however, led to a one-way gradual transfer of the boron atoms from the site of implantation towards the ...

International Nuclear Information System (INIS)

The evolution of metallic substance atomic structure is studied on temperature variation including crystal heating up to melting points, a crystal- liquid phase transition and initiation of a high-density liquid specific structure. It is marked that heat induced changes of simple metal structure can be described as changes around a natural elementary cell which is common for both a crystal and a liquid and consists of a central atom and Z_1 atoms of the first coordination sphere. On this basis the vacancy model of melting is verified. Concentrations of melting vacancies are determined by coordination numbers in the form of Z_1/(1+Z_1)"2 which are the same for both a crystal and a natural elementary cell. The size of natural elementary cells is in an agreement with that of the coordination sphere featured in the liquid and phase transition statistical theory. Calculated data are given for a number of metals, Cs, Eu, Ni, V included

British Library Electronic Table of Contents (United Kingdom)

Nanocrystalline chromium oxynitride films were deposited by reactive RF magnetron sputtering of metallic chromium target in argon and helium atmospheres. The paper deals with consequence of increase in oxygen partial pressure on structural, hydrophobic and optical properties of chromium oxynitride films. The film stoichiometry changes from CrN and Cr2O3 to only Cr2O3 with increase in oxygen partial pressure as evident from X-Ray Diffraction analysis in both cases. The average crystallite size decreases with increase in oxygen partial pressure for both gas atmospheres. The thickness calculated from transmission data and surface profilometer are in good harmony with each other. The deposited films are hydrophobic by nature and the contact angle of the films varies as a function of surface ro...

Science.gov (United States)

In this paper, four different types of pulsed eddy current (PEC) probe are designed and their performance of detecting wall thickness reduction is compared. By using the backward difference method in time and the finite element method in space, PEC signals from various thickness and materials are numerically calculated and three features of the signal are selected. Since PEC signals and features are obtained by various types and sizes of probe, the comparison is made through the normalized features which reflect the sensitivity of the feature to thickness reduction. The normalized features indicate that the shielded reflection probe provides the best sensitivity to wall thickness reduction for all three signal features. Results show that the best sensitivity to thickness reduction is achieved by the peak value, but also suggest that the time to peak can be a good candidate because of its linear relationship with the thickness variation.

Energy Technology Data Exchange (ETDEWEB)

Real-time neutron radiography was demonstrated to be a viable and useful tool in studying water flow in unsaturated media. The experiment was designed to test the method for following water flow. The wetting front advance, water-flow patterns, and neutron attenuation density were observed in a 7.7-cm diameter sand column. The advance was fit with a simple i = A t/sup B/ equation yielding an excellent correlation. Theoretical calculations presented estimate the minimum and maximum detectable water content in various sizes of columns. The ability of real-time neutron radiography to allow both qualitative and quantitative spatial and time measurements to be made in an nonintrusive manner was demonstrated.

Energy Technology Data Exchange (ETDEWEB)

A thermal neutron imaging facility for real-time neutron radiography and computed tomography has recently been developed at the University of Texas TRIGA reactor. Extensive Monte Carlo design calculations were used to determine optimal design parameters of the neutron collimator system to avoid costly trial and error. Thermal neutron flux determined by gold foil activation is 5 {times} 10{sup 6} n/cm{sup 2}{center_dot}s at the primary imaging location with beam size of 22.5 cm in diameter. The collimation ratio can be varied from 125 to 235. The neutron-to-gamma ratio is 7.8 {times} 10{sup 6} n/cm{sup 2}{center_dot}mR. The facility has been tested for radiography and tomography applications and is now fully operational.

CERN Document Server

We have developed a simulation code with the techniques which enhance both spatial and time resolution of the PM method for which the spatial resolution is restricted by the spacing of structured mesh. The adaptive mesh refinement (AMR) technique subdivides the cells which satisfy the refinement criterion recursively. The hierarchical meshes are maintained by the special data structure and are modified in accordance with the change of particle distribution. In general, as the resolution of the simulation increases, its time step must be shortened and more computational time is required to complete the simulation. Since the AMR enhances the spatial resolution locally, we reduce the time step locally also, instead of shortening it globally. For this purpose we used a technique of hierarchical time steps (HTS) which changes the time step, from particle to particle, depending on the size of the cell in which particles reside. Some test calculations ...

CERN Document Server

In this paper we present results of using parallel supercomputers to simulate beam dynamics in next-generation high intensity ion linacs. Our approach uses a three-dimensional space charge calculation with six types of boundary conditions. The simulations use a hybrid approach involving transfer maps to treat externally applied fields (including rf cavities) and parallel particle-in-cell techniques to treat the space-charge fields. The large-scale simulation results presented here represent a three order of magnitude improvement in simulation capability, in terms of problem size and speed of execution, compared with typical two-dimensional serial simulations. Specific examples will be presented, including simulation of the spallation neutron source (SNS) linac and the Low Energy Demonstrator Accelerator (LEDA) beam halo experiment.

International Nuclear Information System (INIS)

Tests on the scrubbing column have led to the following results: Use of a scrubbing column with Raschig rings is only meaningful for the sedimentation of particles exceeding diameters of 0.5 #mu#m; drops of diameter size 1.5 #mu#m are formed in the column; more efficient drop precipitators in the column air flow ease the load on subsequent suspended material filters thereby contributing to a longer life of these filters even at higher sodium ion concentrations in the washing water; with distillate of an 8% rather than 0.8% salt solution a decontamination factor greater than 10 can be calculated since larger particles precipitate more readily. This only applies, however, under the condition that the washing water is renewed regularly, if necessary daily where higher aerosol concentrations are present. If not, the decontamination factor will be reduced through the salt-containing secondary aerosols from the washing water. (orig.).

British Library Electronic Table of Contents (United Kingdom)

The ground state of a three-dimensional (3D) rotating trapped superfluid Fermi gas in the BCS-BEC crossover is mapped to finite N v -body vortex states by a simple ansatz. The total vortex energy is measured from the ground-state energy of the system in the absence of the vortices. The vortex state is stable since the vortex potential and rotation energies are attractive while the vortex kinetic energy and interaction between vortices are repulsive. By combining the analytical and numerical works for the minimal vortex energy, the 2D configurations of N v vortices are studied by taking into account of the finite size effects both on xy-plane and on z-direction. The calculated vortex numbers as a function of the interaction strength are appropriate to the renew experimental results by Zwier...

International Nuclear Information System (INIS)

The energy, angular momentum, and distance (measured from the center of mass of the nucleus) distributions of the effective number of 6q-fluctons are investigated and it is shown that many of the characteristics of these distributions are universal, i.e., independent of the flucton size. ''Saturation'' of the flucton density in nuclei with mass A approx > 80 and certain other features that determine the difference between the behaviors of the effective numbers of fluctons and deuterons are reported. This is used to explain the well known underestimation (by a factor of 1.5--6) of the cross section for the hard inclusive (p, p'd) process on nuclei calculated in the quasielastic formalism. See S. G. Kadmenskii and V. I. Furman, Alpha decay and elated nuclear reactions (in Russian), Energoatomizdat, Moscow, 1985.

Energy Technology Data Exchange (ETDEWEB)

This study reported on the performance of a passive solar radiant floor heating system designed for standard energy-saving farmhouses in northeast China. Weather data in the region was analyzed in terms of solar radiation, temperature, humidity and light levels. The heating characteristics of the building materials such as windows, doors, walls and roofs were also analyzed along with the indoor thermal environment of the farmhouse. The heating load was then calculated along with the size of the thermal storage element and the area of the collector element. The passive solar radiant floor heating system was designed for heating during the winter and cooling in summer. According to the results, the heating characteristics of the system have the potential to improve farming villages environment and the use of renewable energy.

International Nuclear Information System (INIS)

A new evaluation of the 1% time strain limit for creep strength and the isochronous stress/strain relationship was to be undertaken for the type 800 alloy, based on up to date experimental data. After the evaluation of the 1% time strain limit curves and time fracture curves of individual melts, multilinear regression analyses were made to clear up the relationship between parameters of the creep behaviour such as creep strength, 1% time strain limit and time fracture strain on the one hand and metallurgical parameters such as C, Ti, Al, Ni, Cr contents or grain size and type of manufacture, on the other hand. Based on the knowledge gained from these calculations, new limits were determined for HTR material specifications for variants of the 800 alloy of the Rk, NT, DE, and HT type. (orig./DG).

International Nuclear Information System (INIS)

We present differential scanning calorimetry (DSC), X-ray diffractometry, in situ Moessbauer spectroscopy (MS), and transmission electron microscopy (TEM) studies in Metglas ribbons subjected to different heat treatments. The temperature evolution of the hyperfine field H_h_f(T) and the Curie temperature (T_c) of the amorphous phase are determined. The magnetic field originally present in the amorphous phase has a 'normal' behavior, in the sense that it can be described by the Weiss molecular field theory. The total angular momentum of the iron atoms turns out to be 5/2 and this implies Fe"3"+ in which the electronic spins are uncoupled. When the samples are maintained near T_c (#approx#673 K), three new magnetic phases are detected in the Moessbauer spectra, indicating an onset of a crystallization process well below the first crystallization temperature (T_X_1), as determined by DSC (#approx#820 K). The magnetic behavior of these phases is also described by ...

Energy Technology Data Exchange (ETDEWEB)

A computer program for optimization of modular cogeneration plants is introduced. Computer calculation fundamentals are discussed referring to examples which elucidate the verification of the calculated data by measured data or empirical values. The results obtained as one optimizes plants by varying their size or by splitting them into modules are introduced referring to examples. Sensitivity analyses are made to investigate the influence of parameters such as fuel prices, electricity tariffs and interest rates. (orig.) [Deutsch] Im vorliegenden Beitrag wird ein Computerprogramm zur Optimierung von BHKW-Anlagen vorgestellt. Zunaechst werden in einem ersten Schritt die Berechnungsgrundlagen an einem Beispiel in Hinblick auf ihre Ueberpruefung durch Messdaten oder durch Erfahrungswerte diskutiert. Dann werden in einem zweiten Schritt exemplarisch die Ergebnisse einer Optimierung durch Variation der Gesamtanlagengroesse auf ...

International Nuclear Information System (INIS)

We have measured the lattice relaxation around As in Si at a homogeneous As concentration of 4x10"1"8 cm"-"3 by EXAFS spectroscopy. From the absorption spectra, distances up to the 4th shell could be extracted. A sizeable misfit due to an increased distance is only observed for the 1st shell. Complementing our experimental work we have performed ab initio calculations based on the density functional theory with the WIEN97 package which uses the linearised augmented plane wave method and with the FHI96md program which uses first-principles pseudo-potentials and a plane wave basis set to investigate the size dependence of the super-cells constructed around one substitutional As atom. The calculations yielded good agreement with our EXAFS experiment so that the determined relaxations can be used as a solid basis for further interpretations of derived parameters such as hyperfine interaction parameters in defect complexes.

Energy Technology Data Exchange (ETDEWEB)

Mass density of a composite is generally taken as the volume-averaged value of components' densities. Moreover, the same volume-averaged mass density is usually used to calculate the wave speed in the long-wavelength limit, i.e., where the wavelength is much larger than the size of the inhomogeneities. In this paper, we show via rigorous derivation that the dynamic mass density used in the calculation of (long-wavelength) wave speed can differ significantly from the static volume-averaged value. This recognition is shown to yield an excellent account of some recent experimental data, as well as to make possible the realization of acoustic metamaterials. Physical reason for the difference between two mass densities is attributed to the relative motion between the components. That is, the implicit assumption-that all components in a composite must move uniformly in the long-wavelength limit-can be violated in the ...

International Nuclear Information System (INIS)

The objective of this study was to develop a method for 3D subtraction CT angiography and to optimize the visualization after semiautomatic segmentation. Ten patients with aneurysms of the abdominal aorta were examined using spiral CT. To reconstruct the vessels, as well as adjacent organs such as the liver and kidneys, one image data volume was acquired before and after injection of the contrast agent. The CT scans were obtained with a Siemens Somatom Plus 4. To improve the results of automatic segmentation, as well as visualization by maximum intensity projection (i.e. removal of bony structures), subtraction of both image volumes is necessary. However, small translation shifts disturb the subtraction process and produce artificial contours. To calculate the disparities along the three coordinate axes of two corresponding image volumes, a cepstrum filter is applied to a pair of image volumes. After detection of the disparities, which manifest as bright spots, the ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work is to determine the extent to which drill water might be expected to be imbibed by core samples taken from densely welded tuff. In a related experimental study conducted in G-Tunnel, drill water imbibition by the core samples was observed to be minimal. Calculations were carried out with the TOUGH code with the intent of corroborating the imbibition observations. Due to the absence of hydrologic data pertaining directly to G-Tunnel welded tuff, it was necessary to apply data from a similar formation. Because the moisture retention curve was not available for imbibition conditions, the drainage curve was applied to the model. The poor agreement between the observed and calculated imbibition data is attributed primarily to the inappropriateness of the drainage curve. Also significant is the value of absolute permeability (k) assumed in the model. Provided that the semi-log plot of ...

Energy Technology Data Exchange (ETDEWEB)

Individual nanoscale building blocks exhibit a wide range of size-dependent properties, since their size can be tuned over known characteristic length scales of bulk materials. In the last several years, the possibility of combining different materials in the form of two and three component nanoparticles (NPs) has been extensively explored. Also multi-component materials can be obtained via self-assembly of NPs from their binary colloidal mixtures. These new nanocrystal solids may possess tunable collective properties that originate from interactions between size and composition controlled building blocks. Exchange coupling between neighboring NPs of magnetically soft and hard materials enhances the magnetic energy product of the nanocomposite material. Randomly mixed solids of small and large semiconducting CdSe NPs revealed enhancement of photoluminescence intensity of large semiconductor particles accompanied by ...

Energy Technology Data Exchange (ETDEWEB)

The vivo dephosphorylation rate of 2-deoxy-D-glucose 6-phosphate (DGP) in the cerebral cortex of goats injected intravenously with radiolabeled 2-deoxy-D-glucose (DG) was investigated. Serial rapidly frozen samples of parietal cortical gray tissue were obtained at regular intervals over time periods from 45 min to 3 h in awake goats or in paralyzed and artificially ventilated goats maintained under 70% N/sub 2/O or pentobarbital sodium anesthesia. The samples were analyzed for glucose content and separate DG and DGP activities. The rate parameters for phosphorylation (k/sup *//sub 4/) and dephosphorylation (k/sup *//sub 4/) were estimated in each animal. The glucose phosphorylation rate (PR) was calculated over the intervals 3-5 (or 6), 3-10, 3-20, 3-30, and 3-45 min, assuming k/sup *//sub 4/ = O. As the evaluation period was extended beyond 10 min, the calculated PR became increasingly less when ...

International Nuclear Information System (INIS)

In laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), the properties of laser-generated aerosols, such as size and composition, are crucial for matrix-independent quantification. In this study, the aerosol particle morphology and elemental composition generated by two state-of-the-art laser systems (ArF excimer nanosecond-UV laser and Ti:sapphire femtosecond-IR laser) were investigated by electron microscopic techniques. Electrostatic sampling of the aerosols directly onto transmission electron microscopy (TEM) grids allowed us to study the morphology and elemental composition of the aerosols using TEM and TEM-EDX (energy dispersive X-ray spectroscopy) analyses, respectively. The results of the electron microscopic studies were finally compared to the LA-ICPMS signals of the main matrix components. The investigations were carried out for non-conducting materials (glass and zircon), metallic samples ...

International Nuclear Information System (INIS)

In July 2005 a new algorithm was released by Varian Medical Systems for the Eclipse planning system and installed in our institute. It is the anisotropic analytical algorithm (AAA) for photon dose calculations, a convolution/superposition model for the first time implemented in a Varian planning system. It was therefore necessary to perform validation studies at different levels with a wide investigation approach. To validate the basic performances of the AAA, a detailed analysis of data computed by the AAA configuration algorithm was carried out and data were compared against measurements. To better appraise the performance of AAA and the capability of its configuration to tailor machine-specific characteristics, data obtained from the pencil beam convolution (PBC) algorithm implemented in Eclipse were also added in the comparison. Since the purpose of the paper is to address the basic performances of the AAA and of its configuration procedures, only data relative ...

Energy Technology Data Exchange (ETDEWEB)

The importance of cellular dosimetry in both diagnostic and therapeutic nuclear medicine is becoming increasingly recognized. Experimental range-energy relations for electrons and alpha particles, along with derived geometric reduction factors, are used to calculate cellular absorbed fractions for these radiations. The resulting absorbed fractions are employed to calculate cellular S-values for several radionuclides. Cellular absorbed fractions for monoenergetic electron sources with energies ranging from 0.1 keV to 1 MeV, distributed uniformly in the source region, are calculated for several target {l_arrow} source combinations including cell{l_arrow}cell, cell{l_arrow}cell surface, nucleus{l_arrow}nucleus, nucleus {l_arrow}cytoplasm and nucleus {l_arrow}cell surface. Similar data are also provided for monoenergetic alpha particle sources with energies ranging from 3 to 10 MeV. S-values are also conveniently tabulated for ...