bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of oxidation of a U‐2.5 wt% Nb alloy in air at low temperatures: kinetic study and oxide characterization
Authors: Jiangrong Yang , Xiaolin Wang , Lizhu Luo , Ping Zhou 
Published: February 2008

AbstractAlloying uranium with niobium can greatly enhance the corrosion resistance of metallic uranium. In the present article, the oxidation behavior of a U‐2.5 wt% Nb alloy in air over the temperature range 333 to 573 K was investigated. XPS technique was employed to characterize the oxide products. The results of oxidation‐rate curves show that at temperatures below 353 K the oxidation of U‐2.5 wt% Nb alloy follows a parabolic‐rate law, and in the temperature range of 373–423 K paralinear rate laws seem to apply, however, above 473 K linear laws are observed. The oxidation‐rate dependence of temperature is obtained, and the activation energies for different oxidation stages are determined. The XPS analysis indicates that under experimental conditions the predominant oxide formed on the outer surface is stoichiometric UO2.0 intermixed with Nb2O5, and below the outmost thin layer, an inner oxide layer consisting of UO2, NbO is presented. Copyright © 2008 John Wiley & Sons, Ltd.
Investigation of Mn‐dimers formation in silicon by SIMS method
Authors: Saraykin Vladimir , Trifonov Alexey 
Published: February 2008

AbstractIt has been theoretically predicted that manganese atoms in silicon matrix tend to form dimers which can show both ferro‐ and antiferromagnetic properties. One might expect that the significant part of such dimers (N‐mers) should be spattered as cluster ions while SIMS measurement. We have investigated samples of silicon wafers implanted with manganese ions and annealed. In the solid solution the probability of the situation when N doped atoms are nearest neighbours is proportional to Nth power of concentration. However, if in the solution the process of enhancement of neighbouring impurity atoms number takes place, the cluster ion signal should exceed the power law. We have verified the validity of this statement in ion implanted solutions of B and Mn in silicon. SIMS measurements in annealed samples show that the profile of Mn2 and Mn3 ions essentially exceed respectively the square and the cube of manganese concentration. Quantitative estimation shows that in the annealed sample at some depths manganese dimers contain about 10% of total Mn atoms. The connection between the obtained profiles and magnetic measurements is discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Designing systems for adaptability by means of architecture options
Authors: Engel Avner , Browning Tyson R. 
Published: February 2008

AbstractThe value of a system usually diminishes over its lifetime, but some systems depreciate more slowly than others. Diminished value is due partly to the increasing needs and wants of the system's stakeholders and partly to its decreasing capabilities relative to emerging alternatives. Thus, systems are replaced or upgraded at substantial cost and disruption. If a system is designed to be changed and upgraded easily, however, this adaptability may increase its lifetime value. How can adaptability be designed into a system so that it will provide increased value over its lifetime? This paper describes the problem and an approach to its mitigation, adopting the concept of real options from the field of economics, extending it to the field of systems architecture, and coining the termarchitecture optionsfor this next‐generation method and the associated tools fordesign for adaptability. Architecture options provide a quantitative means of optimizing a system architecture to maximize its lifetime value. This paper provides two quantitative models to assess the value of architecture adaptability. First, we define three metrics—component adaptability factors, component option values, andinterface cost factors—which are used in a static model to evaluate architecture adaptability during the design of new systems. Second, we enhance a dynamic model to evaluate architecture adaptability over the maintenance and upgrade lifetime of a system, formulating aDesign for Dynamic Value(DDV) optimization model. We illustrate both models with quantitative examples and also discuss how to obtain the socio‐economic data required for each model. © 2008 Wiley Periodicals, Inc. Syst Eng
Speed adaptive mobile IP over wireless LAN
Authors: Tian Jun , Helal Abdelsalam (Sumi) 
Published: February 2008

AbstractIn this paper, the performance of MIP/WLAN at different moving speeds is evaluated on a testbed. The result shows that current MIP protocol is not suitable for rapid moving environments. Through analyzing the relationship of the performance and the moving speed and breaking down the handoff latency of MIP over WLAN, we propose a speed adaptive MIP protocol extension. In this protocol extension, a concept, handoff rate, is defined and is used to extend the MIP protocol. An evaluation of the speed adaptive MIP shows that it greatly improves the performance of MIP over WLAN in rapid moving environments. Copyright © 2008 John Wiley & Sons, Ltd.
A future location‐aware replacement policy for the cache management at the mobile terminal
Authors: Drakatos Stylianos , Pissinou Niki , Makki Kia , Douligeris Christos 
Published: February 2008

AbstractWhile the traditional data shipping systems use physical information to organize data, a newer data caching technique maintains both associated answers (data items) of previous queries and their meaning (purpose). This form of information description is called semantic description, and it makes it possible to reason about and derive knowledge from the given description. In a distributed heterogeneous environment, such as the mobile environment, the semantic data caching paradigm is an important technique for improving the performance of wireless data dissemination systems. Data caching performance depends heavily on the replacement policy being used for the cache management. However, future location uncertainty, limited client resources and frequent client disconnections make cache management a challenge.This paper proposes a future location‐aware cache replacement policy to manage a semantic cache. The proposed replacement policy uses the validity of the data fetched from the server and the neighboring locations to decide which of the cache entries is less likely to be needed in the future, and therefore a good victim for eviction when cache space is needed. The replacement policy's preference for cached items to be evicted is modeled as a general function that declines with distance between the mobile user's current location and the candidate for replacement cached item's bound location. For better efficiency, the overall replacement granularity is dynamically achieved along three levels: ring, cell and data item. Simulation study of the proposed approach shows that it outperforms both the least recently used (LRU) and furthest away replacement (FAR) schemes, where only temporal locality is considered. Moreover, the proposed scheme is easier to implement than other research and development proposals. Copyright © 2008 John Wiley & Sons, Ltd.
PIXE and ionoluminescence for Mesoamerican jadeite characterization
Authors: Ruvalcaba‐Sil J. L. , Manzanilla L. , Melgar E. , Lozano Santa Cruz R. 
Published: February 2008

AbstractGreenstones were highly appreciated in pre‐Hispanic Mesoamerica. Most of the finest green artifacts were worked in jadeite and other minerals such as serpentine and nephrite. Jadeite, the most precious stone in ancient Mesoamerica, was widely used and traded since the Preclassic Horizon (1500 B.C.). The main beds are located in the Maya region, in the Motagua area of Guatemala. In this work, three pieces of a necklace of greenstones from an offering (corresponding around 155 A.D.) discovered in an extensive excavation carried out in the palatial structure of Xalla, at Teotihuacan site, in the central highlands of Mexico, were studied using external beam particle induced x‐ray emission (PIXE). The necklace is composed by 11 round pieces of green colors ranging from light to dark green. The aim of this study is to determine the elemental composition of the greenstones and to establish the sourcing, trade and relationship between these regions. Thus, several jadeite samples from Manzanal sources of Motagua were analyzed as well. The elemental composition comparison between the archaeological items and the known jadeite samples indicates that only one archaeological piece is related to the Manzanal sample source. Green luminescence of high intensity was observed for the archaeological pieces but only in one case the luminescence was blue–violet. When comparing with green stone mineral samples, only jadeite presented luminescence. The spectra, corresponding mainly to Mn2+, Ce3+ and Al3+ emissions, were collected under proton induced luminescence in vacuum on the jadeite samples. No correlation was observed among light emission color and jadeite sources. Copyright © 2008 John Wiley & Sons, Ltd.
DT2, a PIXE spectra simulation and fitting package
Authors: Reis M. A. , Chaves P. C. , Alves L. C. , Barradas N. P. 
Published: February 2008

AbstractRecently, a new PIXE code, LibCPIXE, was produced as a variant to the old DATTPIXE package following a simulation‐based approach usually not used in PIXE data handling. This approach required to merge the PIXE data handling code, LibCPIXE to NDF, a well‐known code for handling RBS and other IBA methods data, and showed that complex structures in the samples can dramatically change the observed PIXE yields. A full stepwise process was then undertaken in order to produce a new PIXE data handling code that uses the simulation approach not only to estimate the number of K‐α and L‐α x‐rays emitted by the elements present in structured samples but to fit the entire PIXE energy spectra. This approach is of particular importance for the new high x‐ray energy and high resolution PIXE set‐up being installed at ITN, for the precise interpretation of PIXE spectra from complex targets, and also as a robust basis to relative yield ion energy dependence (RYIED) work discussed elsewhere in this conference. In this communication we present the fitting core for the new DT2 package and discuss its capacity. Copyright © 2008 John Wiley & Sons, Ltd.
Particle size/composition relationships of wind‐eroding sediments, Owens (dry) Lake, California, USA
Authors: Rojo Lila , Gill Thomas E. , Gillette Dale A. 
Published: February 2008

AbstractMajor, minor, and trace element concentrations were determined by particle‐induced x‐ray emission (PIXE) in 118 aeolian sediment samples collected at six heights in seven locations along a 1.2 km transect during three sequential dust storms at Owens (dry) Lake, California, USA. Na and S concentrations covaried with each other (and inversely with Si and Ca), increased with height, and decreased with distance downwind and time. Mg, Al, Si, K, Mn, Fe, and Sr concentrations at northerly sites varied with height and location as opposed to nearly constant concentrations at southerly locations. Volumetric particle‐size distribution (PSD) for each sample was determined via laser diffraction. PSDs of the collected sediment reflected a trimodal distribution:63% of samples peaked at 20–50 µm (silt), 11% at 50–100 µm (very fine sand) and 26% at 100–250 µm (fine sand). Most silty samples occurred during the first two events. Significant differences in element concentrations existed in relation to the PSDs. Na and S concentrations were proportional to the submicron to silt particle fraction during each event. Al, Ti, Mn, K, Fe, and Rb concentrations correlated with 100–500 µm (fine/medium sand) particles in the first two events and a wider PSD range 250–1000 µm (coarse sand) in the third event. The results suggest sodium sulfate aerosol emission during the first windstorm, while subsequent saltation‐dominated events released more aluminosilicate minerals containing higher trace metal concentrations. These combined techniques reveal particle size/chemical fractionation and spatial variability of sediment properties during resuspension at aeolian ‘hotspots,’ with implications to geochemical cycling and aerosol source/receptor relationships. Copyright © 2008 John Wiley & Sons, Ltd.
Silicon detector dead layer thickness estimates using proton bremsstrahlung from low atomic number targets
Authors: Cohen David D. , Stelcer Eduard , Siegele Rainer , Ionescu Mihail 
Published: February 2008

AbstractProton‐induced bremsstrahlung radiation in the 1–5 keV energy range has been used to estimate the silicon dead layer thickness in a Si(Li) detector. This novel technique does not require accurate bremsstrahlung cross sections with x‐ray energy; it just assumes these cross sections and hence the efficiency corrected yield is both smooth and continuous across the Si K edge at 1.838 keV. Copyright © 2008 John Wiley & Sons, Ltd.
Localisation of trace metals in metal‐accumulating plants using µ‐PIXE
Authors: Siegele R. , Kachenko A. G. , Bhatia N. P. , Wang Y. D. , Ionescu M. , Singh B. , Baker A. J. M. , Cohen D. D. 
Published: February 2008

AbstractParticle induced x‐ray emission (PIXE) is a very sensitive technique that can quickly and reliably measure a wide range of elements simultaneously with high sensitivity. Using a focused microbeam, elemental distributions can be mapped with high spatial resolution. We demonstrate high‐resolution mapping of metals in plant leaves at 5 µm resolution and its application in detecting sites of metal accumulation in metal‐accumulating plant tissues. The importance of biological sample preparation is discussed by direct comparison of freeze‐substitution and freeze‐drying techniques routinely used in biological sciences. The advantages and limitations of quantitative elemental imaging using these techniques are also discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Microbeam analysis of yellow sand dust particles
Authors: Matsuyama S. , Ishii K. , Yamazaki H. , Kikuchi Y. , Kawamura Y. , Oyama R. , Yamanaka K. , Yamamoto T. , Watanabe M. , Tsuboi S. , Arao K. 
Published: February 2008

AbstractA microbeam system was applied to analyses of yellow sand dust particles. Such particles from the Asian continent sometimes cause turbid conditions in Japan, especially in spring, and are sometimes changed by mixing with anthropogenic and marine aerosols. For better understanding of their formation mechanism, analysis of single particles is indispensable. For this purpose, we developed a microbeam analysis system at Tohoku University with a spatial resolution of better than 1 µm. The system comprises two x‐ray Si(Li) detectors for particle‐induced x‐ray emission (PIXE), an annular ion‐implanted Si detector for Rutherford backscattering (RBS), an ion‐implanted Si detector for off‐axis scanning transmission ion microscopy (STIM), and a Si‐PIN photodiode for direct STIM analyses. The combination of PIXE, RBS and off‐axis STIM methods enabled simultaneous analyses of hydrogen to metal elements and revealed the chemical compositions of these particles. Yellow sand dust particles were impacted on a thin polycarbonate film and analyzed using the microbeam analysis system. After quantification of the elemental components of these particles, the chemical composition of each particle was obtained. Silicon, calcium, oxygen, carbon, and hydrogen are the main composing elements of the particles originating mainly from soil dust from the Asian continent. The particles contain sulfur and heavier elements too, originating from mixing with anthropogenic aerosols. Sodium, magnesium, and chlorine, which come from marine aerosols, are also included in these particles and might be adsorbed during transport from the Asian continent. Single particle analysis of yellow sand dust will engender a better understanding of their formation process during transport. Copyright © 2008 John Wiley & Sons, Ltd.
Benefits of combined PIXE and AMS with new accelerators
Authors: Demortier Guy , Quarta Gianluca , Butalag Karim , D'Elia Marisa , Calcagnile Lucio 
Published: February 2008

AbstractCombination of the elemental nondestructive analysis of artifacts by ion beam analysis (IBA) multielemental techniques (but mostly PIXE) with the accelerator mass spectroscopy (AMS) measurement of the age of the organic material discovered in the close vicinity of these artifacts (mainly available for recent excavations) gives new tools to archaeologists to improve their diagnosis in the study of the composition of ancient objects and of their workmanship in ancient times by using the same experimental facility for IBA and AMS. For potteries and metallic samples, IBA and AMS are to be applied on different samples excavated in the same environment but for organic archaeological samples, IBA and AMS techniques could be sequentially used on the same material. Results of these combined techniques on artifacts of various origins recently studied at CEDAD (CEntro di Datatione e Diagnostica), University of Salento, Lecce, Italy, are presented. Copyright © 2008 John Wiley & Sons, Ltd.
Empirical approximation for Lα production cross sections
Authors: Šmit Ž , Tancek A. 
Published: February 2008

AbstractThe production cross sections for Lα x‐ray lines of the elements Z = 47–92 induced with protons up to 4‐MeV energy are given by a simple empirical expression suitable for thick‐target particle induced x‐ray emission (PIXE) applications. The logarithm of Lα1, 2 production cross section is expressed as an eight‐parameter rational function of the logarithm of the proton energy. The parameters were obtained by fitting the function to the tabulated data of Reis and Jesus (Atomic Data and Nuclear Data Tables 1995; 63). The accuracy of the fit is within several percent in the high‐energy region, about 5% in the vicinity of the discontinuous jumps of the tabulated data, and about 10–20% in the low‐energy region below 200 keV. Copyright © 2008 John Wiley & Sons, Ltd.
Chemical composition and mass closure for PM2.5 and PM10 aerosols at K‐puszta, Hungary, in summer 2006
Authors: Maenhaut Willy , Raes Nico , Chi Xuguang , Cafmeyer Jan , Wang Wan 
Published: February 2008

AbstractA comprehensive chemical aerosol characterisation was carried out at K‐puszta, Hungary, from 24 May until 29 June 2006. Up to 11 June it was unusually cold at the site, but from 12 June onwards it was warm. PM2.5 and PM10 samplers with Nuclepore polycarbonate filters and quartz fibre filters were deployed in parallel for mostly day and night collections. All samples were analysed for the particulate mass (PM) by weighing. The Nuclepore polycarbonate filters were analysed for up to 29 elements by particle‐induced x‐ray emission spectrometry (PIXE) and for major anions and cations by ion chromatography. The quartz fibre filters were analysed for organic and elemental carbon by a thermal‐optical transmission technique. The atmospheric concentrations of the PM and most species and elements were higher during the warm period than during the cold one. Aerosol chemical mass closure calculations were done for the PM2.5 and PM10 aerosols. As gravimetric PM data we used the data from the Nuclepore polycarbonate filters. For reconstituting this PM, eight aerosol components were considered. Organic matter contributed by far the most to the PM2.5 and PM10 PM; it was responsible for 40–50% of the average PM. Noteworthy were the much larger percentages of crustal matter during the warm period than during the cold one. In the PM2.5 aerosol, crustal matter accounted for 17% of the average PM during the warm period, but only for 3.1% during the cold period. For the PM10 aerosol, the percentages were 28% in the warm period and 10% in the cold one. Copyright © 2008 John Wiley & Sons, Ltd.
Two Different Surgical Approaches in the Treatment of Adenocarcinoma at the Gastroesophageal Junction
Authors: Johansson Jan , Djerf Pauline , Öberg Stefan , Zilling Thomas , von Holstein Christer Staël , Johnsson Folke , Walther Bruno 
Published: February 2008

AbstractBackgroundAdenocarcinoma at the gastroesophageal junction may be regarded as of esophageal or of gastric origin, and tumor removal may follow the principles of esophagectomy or extended gastrectomy. We determined the impact of this strategy on our patients with tumors at this site.MethodsBaseline patient and tumor characteristics were collected, and tumors were categorized according to Siewert’s classification (I, II, or III) of gastroesophageal junction tumors. Totally, 133 patients were operated on between 1990 and 2001. Ninety‐six patients with type I (n = 67), II (n = 26), and III (n = 3) tumors underwent esophagectomy and gastric tube reconstruction, and 37 patients with type I (n = 5), II (n = 26), and III (n = 6) tumors underwent extended gastrectomy and long Roux‐en‐Y reconstructions.ResultsAfter adjusting for the independently significant impact factors—tumor stage, tumor dissection (R0–R2), and length of tumor free resection margins—we did not find any specific survival benefit associated with either of the two evaluated surgical approaches for tumor resection and reconstruction. The EORTC quality of life forms revealed good results as indicated by the functional scales and the symptom scales.ConclusionsProvided that adequate tumor dissection is performed, patients with adenocarcinoma at the gastroesophageal junction can be resected and reconstructed using the principles for esophagectomy or extended gastrectomy.
Public Health Asks of Community Psychology…
Authors: Green Lawrence W. 
Published: February 2008

AbstractAs the field of public health has increasingly recognized the social and behavioral aspects of the changing epidemiology of diseases and injuries, it has added social and behavioral scientists to the faculties of schools of public health and most federal and state public health agencies. Community psychology can play a crucial role in helping to bridge the dominant psychological theories with the family and community contexts in which individuals are conditioned and reinforced in their tendencies toward violent behavior. Public health asks of community psychology a helping hand in bridging the clinical endpoints of most NIH‐sponsored behavioral research with the community endpoints of most CDC‐sponsored programs such as injury control.
Assembly of Silver Nanoparticles into Hollow Spheres Using Eu(III) Compound based on Trifluorothenoyl-Acetone
Authors: Sun Youyi , Liu Yaqing , Zhao Guizhe , Zhang Qijin 
Published: February 2008

Abstract
The preparation of luminescent silver hollow spheres using Eu(III) compound based on trifluorothenoyl-acetone is described. The structure and size of silver hollow spheres were determined by TEM images. The result shows the formation of hollow structure and average size of the silver hollow spheres (0.9 μm). The silver hollow spheres were further characterized by UV absorption spectrum, SNOM and SEM images, suggesting them to be formed by self-assemble of some isolated silver nanoparticles. The luminescent properties of them were also investigated and they are shown to be high emission strength; moreover, they offer the distinct advantage of a lower packing density compared with other commercial luminescent products.