bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Number of Required Observations in Data Assimilation for a Shallow-Water Flow
Authors: Whartenby William G. , Quinn John C. , Abarbanel Henry D. I. 
Published: January 2013

AbstractThe authors consider statistical ensemble data assimilation for a one-layer shallow-water equation in a twin experiment: data are generated by an N × N enstrophy-conserving grid integration scheme along with an Ekman vertical velocity at the bottom of an Ekman layer driving the flow and Rayleigh and eddy viscosity dissipation damping the flow. Data are generated for N = 16 and the chaotic flow that results is analyzed. This analysis is performed in a path-integral formulation of the data assimilation problem. These path integrals are estimated by a Monte Carlo method using a Metropolis Hastings algorithm. The authors' concentration is on the number of measurements Lc that must be assimilated by the model to allow accurate estimation of the full state of the model at the end of an observation window. It is found that for this shallow-water flow approximately 70% of the full set of state variables must be observed to accomplish either goal. The number of required observations is determined by examining the number needed to synchronize the observed data Lc and the model output when L data streams are assimilated by the model. Synchronization occurs when and the correct selection of which data are observed is made. If the number of observations is too small, so synchronization does not occur, or the selection of observations does not lead to synchronization of the data with the model output, state estimates during and at the end of the observation window and predictions beyond the observation window are inaccurate.
Mesoscale Influences of Wind Farms throughout a Diurnal Cycle
Authors: Fitch Anna C. , Lundquist Julie K. , Olson Joseph B. 
Published: January 2013

Abstract
Large wind farms are expected to influence local and regional atmospheric circulations. Using a mesoscale parameterization of the effects of wind farms that includes a momentum sink and a wind speed–dependent source of turbulent kinetic energy, simulations were carried out to quantify the impact of a wind farm on an atmospheric boundary layer throughout a diurnal cycle. The presence of a wind farm covering 10 km × 10 km is found to have a significant impact on the local atmospheric flow and on regions up to 60 km downwind at night. Daytime convective conditions show little impact of the wind farm on wind speeds, as the momentum deficits generated by the wind farm rapidly mix through the depth of the boundary layer. At night, the stable layer within the rotor area inhibits turbulent mixing of the momentum deficit, leading to a shallower wake and a greater reduction in the wind speed within the wake. Although a low-level jet forms at altitudes within the rotor area in the hours before dawn, it is completely eliminated within the wind farm. At night, a maximum warming of 1 K is seen at the bottom of the rotor area. Near the surface, there is less warming (0.5 K). Downwind, the surface temperature perturbation is small, with a cooling of up to 0.3 K. Over the simulation period, the mean temperature change over the wind farm area at 2 m is a very slight warming (0.2 K). Mean temperature changes downwind are negligible. Other influences on turbulent kinetic energy, surface heat fluxes, and boundary layer height, are discussed.
Subseasonal Prediction of Wintertime North American Surface Air Temperature during Strong MJO Events
Authors: Rodney Marcel , Lin Hai , Derome Jacques 
Published: January 2013

Abstract
A multivariable linear regression model is constructed based on the status of the Madden–Julian oscillation (MJO) and persistence in order to forecast wintertime surface air temperature anomalies over North America out to 4 pentads (20 days). The current and previous states of the MJO are utilized as predictors, based on the Real-time Multivariate (RMM) indices of Wheeler and Hendon. Beyond the persistence-driven first pentad, potentially useful skill is mainly observed during strong MJO events in phases 3, 4, 7, and 8, which correspond to a dipole diabatic heating anomaly in the tropical Indian Ocean and western Pacific. This skill is largely centered over the eastern United States and the Great Lakes region during pentads 2 and 3.
Evaluation of airflow pattern in wind-driven naturally ventilated atrium buildings: measurement and simulation
Authors: Li ZR , Ai ZT , Wang WJ , Xu ZR , Gao XZ , Wang HS 
Published: January 2013

This article presents a study of airflow pattern inside a five-story wind-driven naturally ventilated atrium building. Firstly, field measurement conducted in the atrium building reveals the existence of reversed flows from the atrium to windows, which could cause air cross-contamination between floors during the period of an infectious disease outbreak. The computational fluid dynamics technique was then employed to further investigate the airflow pattern inside the building, under different wind directions and opening ratios. It is found that the airflow pattern inside a wind-driven naturally ventilated atrium building is very sensitive to the oncoming wind direction. Under parallel and perpendicular incident wind directions, the existence of adversely reversed flows in a certain floor and the re-entry of used air from an upper floor into its adjacent lower floors through the atrium results in the decrease of indoor air quality and the effective air exchange through windows. Nevertheless, the building has good natural ventilation performance under oblique incident wind direction, although the expected role of the atrium is still not fully achieved. In addition, the improvement of airflow pattern inside wind-driven naturally ventilated buildings cannot be achieved by simply modifying the opening ratios. Practical application: Considering the indoor airflow pattern could substantially influence the elimination efficiency of pollutants and overheated air, this study is expected to help designers and engineers who are considering the use of an atrium at the design stage to have a better understanding of the airflow pattern inside a wind-driven naturally ventilated atrium building.
Purification and characterization of glucose 6-phosphate dehydrogenase enzyme from rainbow trout (Oncorhynchus mykiss) liver and investigation of the effects of some metal ions on enzyme activity
Authors: Comakli Veysel , Akkemik Ebru , Ciftci Mehmet , Kufrevioglu Omer Irfan 
Published: January 2013

Glucose 6-phosphate dehydrogenase (d-glucose 6-phosphate: NADP+ oxidoreductase, EC 1.1.1.49; G6PD) is a key enzyme that is localized in all mammal tissues, especially in cytoplasmic sections and that catalyzes the first step of pentose phosphate metabolic pathway. In this study, G6PD enzyme was purified 1444-fold with a yield of 77% from rainbow trout liver using 2′,5′-ADP-sepharose-4B affinity chromatography. Moreover, a purity check of the enzyme was performed with sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Some characteristic features like optimal pH, stable pH, optimal temperature and optimal ionic strength were determined for the purified enzyme. In addition to this, in vitro effects of ions like silver nitrate (Ag+), thallium sulphate (TI+), cobalt (II) nitrate (Co2+) and arsenic (V) oxide (As5+) on enzyme activity were researched. Half-maximal inhibitory concentration (IC50) values of Ag+, Co2+ and As5+ metal ions, which showed an inhibitory effect, were found to be 0.0044, 0.084 and 4.058 mM, respectively; and their inhibition constants ( Ki) were found to be 0.0052 ± 0.00042, 0.087 ± 0.015700 and 4.833 ± 1.753207 mM, respectively. Tl+ not exhibited inhibitory effect on the enzyme activity.
Synthesis, proton conductivity and chemical stability of novel sulfonated copolyimides-containing benzimidazole groups for fuel cell applications
Authors: Gu Xingzhong , Xu Nan , Guo Xiaoxia , Fang Jianhua 
Published: January 2013

A new diamine monomer, 2,2′-bis(4-aminophenyl)-5,5′-bibenzimidazole (BAPBI), has been simply synthesized via a one-step reaction procedure of 4-aminobenzoic acid and 3,3′-diaminobenzidine in polyphosphoric acid (PPA) at 190°C. A series of sulfonated copolyimides (SPIs)-containing benzimidazole groups have been prepared by random copolymerization of 1,4,5,8-naphthalenetetracarboxylic dianhydride, BAPBI, 4,4′-bis(4-aminophenoxy)biphenyl-3,3′-disulfonic acid and nonsulfonated diamines in m-cresol at 180°C. Transparent and tough SPI membranes are obtained by solution cast method. The SPIs show high decomposition temperatures (∼300°C) of sulfonic acid groups, indicating good thermal stability. Covalent cross-linking was successfully achieved by treating the SPI membranes in PPA at 170°C for 10 h. The covalently cross-linked SPI membranes show much improved radical oxidative stability due to the synergic action of the covalent cross-linking and the incorporation of benzimidazole groups into the polymer structure. The covalent cross-linking is also favorable for improving the hydrolytic stability of the SPI membranes. However, the proton conductivity decreased to some extent because the sulfonic acid groups had been partially consumed during the process of covalent cross-linking.
Synthesis and properties of novel random copolymers of poly(ether ketone ether ketone ketone)–poly(ether ketone sulfone imide)
Authors: Zhou Minghong , Sun Yongfeng , Yu Yikai , Cai Mingzhong 
Published: January 2013

The monomer containing sulfone and imide linkages, namely bis[4-( p-phenoxybenzoyl)-1,2-benzenedioyl]- N, N, N′, N′-4,4′-diaminodiphenyl sulfone (BPBDADPS), was prepared by the Friedel–Crafts reaction of bis(4-chloroformyl-1,2-benzenedioyl)- N, N, N′, N′-4,4′-diaminodiphenyl sulfone with diphenyl ether. Novel random copolymers of poly(ether ketone ether ketone ketone)–poly(ether ketone sulfone imide) were synthesized by the electrophilic Friedel–Crafts acylation polycondensation of terephthaloyl chloride with a mixture of 4,4′-diphenoxybenzophenone and BPBDADPS in the presence of anhydrous aluminum chloride and N-methylpyrrolidone in 1,2-dichloroethane. The random copolymers with 10–35 mol% BPBDADPS are semicrystalline and had remarkably increased glass transition temperatures ( Tgs) over the conventional poly(ether ether ketone) and poly(ether ketone ketone) due to the incorporation of polar sulfone and imide linkages in the main chains. The copolymers IV and V with 30–35 mol% BPBDADPS had not only high Tgs of 184–186°C but also moderate melting temperatures ( Tms) of 336–340°C, having good potential for melt processing. The copolymers IV and V had tensile strengths of 100.8–103.6 MPa, Young’s moduli of 2.31–2.48 GPa, and elongations at break of 10.9–12.4% and exhibited high thermal stability and good resistance to organic solvents.
High-performance nanostructure chiral poly(amide–imide)s containing benzamide and amino acid linkages: Preparation, characterization and ultrasonic effect on the morphology
Authors: Mallakpour Shadpour , Ayatollahi Hesan 
Published: January 2013

In this research work, several novel optically active nanostructure poly(amide–imide)s (PAIs) were synthesized from the direct polycondensation reaction of 3,5-diamino- N-(pyridin-3-yl) benzamide with chiral diacids based on trimellitic anhydride-derived dicarboxylic acids containing different natural amino acids such as l-methionine, S-valine, l-alanine and l-isoleucine in green medium consisting of molten tetrabutylammonium bromide. The diamine was synthesized by a two-step reaction. At first, 3,5-dinitro- N-(pyridin-3-yl)benzamide was prepared from the reaction of one equimolar of 3-amino pyridine and one mole of 3,5-dinitrobenzoyl chloride. In the next step, the obtained dinitro was reduced by Pd/C and hydrazine hydrate. The new thermally stable optically active PAIs with inherent viscosity ranging from 0.31 to 0.46 dL g−1 were obtained with high yield. The synthesized polymers were characterized with Fourier transform infrared, proton-nuclear magnetic resonance spectroscopy, specific rotation measurements, thermogravimetric analysis, x-ray diffraction, field emission scanning electron microscopy (FE-SEM) and elemental analysis techniques. Morphological study by FE-SEM showed that these new PAIs were noncrystalline and nanostructure polymers with particle size between 50 and 70 nm. The effect of ultrasonic radiation on the obtained nanostructured polymers showed that the size of polymeric nanoparticles was reduced to about 30–45 nm.
Effect of a Single High Loading Dose of Rosuvastatin on Percutaneous Coronary Intervention for Acute Coronary Syndromes
Authors: Wang Zhengzhong , Dai Hongyan , Xing Mingqing , Yu Zhongxiang , Lin Xianru , Wang Shoudong , Zhang Junyi , Hou Fangjie , Ma Ying , Ren Yongqiang , Tan Kai , Wang Yanping , Ge Zhiming 
Published: January 2013

Objectives: A high loading dose of atorvastatin has been confirmed to reduce postprocedural events in patients undergoing percutaneous coronary intervention (PCI). In this study, we sought to investigate the protective effects of rosuvastatin in patients with acute coronary syndromes (ACS) undergoing PCI and to determine the effect of rosuvastatin pretreatment on the postprocedural levels of high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and monocyte chemotactic protein 1 (MCP-1). Methods: A total of 125 patients with non-ST-segment elevation ACS were randomized to pretreatment with rosuvastatin (20 mg 2-4 hours before PCI [n = 62]) or placebo (n = 63). All the patients received subsequent long-term rosuvastatin treatment (10 mg/d). The main end point of the trial was the 30-day incidence of major adverse cardiac events (death, myocardial infarction, or unplanned revascularization). Plasma levels of hs-CRP, IL-6, and MCP-1 were detected before PCI and 6 hours, 24 hours, and 3 days after PCI. Results: The primary end point occurred in 8.1% of the patients in the rosuvastatin arm and 22.2% in the placebo arm ( P < .01); this difference was entirely attributed to a reduced incidence of myocardial infarction (8.1% vs 22.2%; P < .01). The postprocedural elevation in creatine kinase-MB and troponin I was also significantly lower in the rosuvastatin group at 6 hours, 24 hours, and 3 days. Plasma levels of hs-CRP, IL-6, and MCP-1 increased significantly after PCI in both the rosuvastatin and control groups; however, the postprocedural elevations in hs-CRP and IL-6 levels were significantly lower in the rosuvastatin group than the control group. Conclusions: A single, high dose (20 mg) of rosuvastatin prior to PCI reduces postprocedural myocardial injury in patients with ACS, with a concomitant attenuation of the postprocedural increase in hs-CRP and IL-6 levels.
Sound science in geological disposal in the United Kingdom
Authors: Tweed C. J. 
Published: January 2013

AbstractThe safe implementation of geological disposal must be underpinned by sound science. This paper describes the approaches taken by the Nuclear Decommissioning Authority Radioactive Waste Management Directorate, the implementing body for geological disposal in the UK, to build an evidence
base of scientific data and understanding which is robust to scrutiny and so provides confidence in the safety of geological disposal.
Waste container durability: monitoring of a stainless steel 4 metre box over 12 years
Authors: Smart N. R. , Winsley R. J. , Fennell P. A. H. , Reddy B. , Rance A. P. , Padovani C. 
Published: January 2013

AbstractIn the UK, most intermediate level radioactive waste is packaged in stainless steel containers. It is important that containers should maintain their integrity for extended periods of storage prior to final disposal. A prototype 4 metre box fabricated from 304S11 stainless steel was monitored at an inland rural building for over twelve years to gain experience in monitoring environmental conditions and corrosion during storage. A wide range of different types of aerosol particles were observed on the surfaces and in the air. They contained corrosive ions such as chloride, as well as other anions such as sulfate and nitrate. The chloride deposition rate was between 0.1 and 4 μg cm−2 yr−1 depending on the orientation and location of the surface, with a chloride/sulfate ratio ranging from ∼0.3–2. The temperature and relative humidity typically ranged from 0–30°C and 40–90%, respectively. The greatest degree of corrosion developed on the base of the box, which had elevated chloride concentrations (10–140 μg cm−2). However, there was little evidence of corrosion propagation on the surface of the box and no evidence of stress corrosion cracking. The average pit propagation rates on a 316L coupon mounted next to the 4 m box were <1 μm yr−1.
Corrosion and expansion of grouted Magnox
Authors: Cronin J. , Collier N. 
Published: January 2013

AbstractWith potential storage of several hundred years underground in a geological disposal facility (GDF) before closure, there is a requirement for radioactive waste packages to perform adequately. Over the past 25 years, cementitous grouts based on blast furnace slag (BFS) and ordinary Portland cement (OPC), have been used in the UK to immobilize intermediate-level waste (ILW), Magnox swarf, and currently such wasteforms are in surface storage awaiting geological disposal. Magnox fuel cladding will slowly corrode when encapsulated in alkaline cementitious grouts to produce hydrogen gas and an expansive corrosion product. Expansive corrosion products may lead to degradation of the wasteform and, if extensive, could affect the container. This study investigated the acute and chronic rates of corrosion of unirradiated Magnox swarf encapsulated in a BFS/OPC grout over a range of temperatures (25, 40, 60, 75 and 90°C) for curing times of up to 2½ years. Structural product degradation starts to develop as the tensile strength of the grout is approached by the expansive forces generated. Deformation of some experimental containers was also noted. An estimate of the time taken for a grouted product to fracture from this study due to the corrosion solely of Magnox is 350 years for storage at 25°C. Although not fully described in this paper, the main cement phases were calcium silicate hydrate, portlandite and gehlenite; the main product of Magnox corrosion was brucite. The curing temperature did not affect the compositions of the Magnox metal, corrosion product or grout.
Release of uranium from candidate wasteforms
Authors: Collier N. , Harrison M. , Brogden M. , Hanson B. 
Published: January 2013

AbstractLarge volumes of depleted natural and low-enriched uranium exist in the UK waste inventory. This work reports on initial investigations of the leaching performance of candidate glass and cement encapsulation matrices containing UO3 powder as well as that of uranium oxide powders. The surface areas of UO3 powder and the monolith samples of UO3 conditioned in the glass and cement matrices were very different making leaching comparisons difficult. The results showed that for both types of monolith conditioned samples a steady increase of uranium concentration in solution with time was generally not observed. The wt.% of uranium leached from UO3 conditioned in the lead borosilicate glass wasteform was approximately five orders of magnitude less than that leached from UO3 powder. Similarly, the quantities of uranium leached from UO3 conditioned in composite cement made with ordinary Portland cement, and from magnesium phosphate cement, were approximately four and three orders of magnitude, respectively, less than that leached from UO3 powder. The performance of a mixed oxide borosilicate glass wasteform was only slightly better than that of UO3 powder. This work shows that wasteforms based on encapsulation in lead borosilicate glass and cement matrices have the greatest potential for further development.
Site-bond modelling of porous quasi-brittle media
Authors: Jivkov A. P. , Gunther M. , Travis K. P. 
Published: January 2013

AbstractGeological repository designs employ a multi-barrier approach. The materials, which include wasteforms, backfill and host rock, are typically porous quasi-brittle. Mechanical damage (e.g. nucleation and growth of microcracks) can result in significant changes in permeability. A knowledge of how the permeability is affected is critical to accurate modelling of radionuclide transport. This work proposes a novel 3D lattice-type model for the damage evolution in such materials, referred to as the site-bond model. Its advantages over previous models are that the shape of the lattice cell is physically realistic and that any macroscopic elastic response can be represented, including those of cementitious and geological materials. Damage accumulates as bonds fail upon reaching prescribed failure strengths. These are dictated by a predefined pore size distribution. Concrete is used as a study material. It is demonstrated that the model can predict the macroscopic stress–strain response under unconfined tension and compression with emergent non-linearity due to damage evolution. Ongoing work on the prediction of permeability changes with damage is discussed. This is based on the interaction between the model proposed here and a lattice model of the pore space.
Break-up testing of waste-form materials
Authors: Metcalfe M. P. , Koch W. , Turner G. 
Published: January 2013

AbstractThe Nuclear Decommissioning Authority (NDA) is developing a safety case for the long-term management of higher activity wastes. This includes safety assessments of transport to and operations at the repository. One of the main faults and hazards to be considered is waste package response to impact accidents.The criteria of impact performance for waste packages are based upon activity release of particulates generated from the break up of the waste form during impact. The NDA approach to impact performance is based upon waste package response from finite element modelling in combination with break-up tests.Previous break up research commissioned by the NDA has concentrated on commercial graphite and glass samples. These extended studies, undertaken by the National Nuclear Laboratory in collaboration with the Department of Aerosol Technology of the Fraunhofer Institute of Toxicology and Experimental Medicine, provide break-up data specific to nuclear facilities and waste materials. These include archived unirrradiated graphite used to construct Magnox reactor cores and reflectors, simulant high level waste glass, selected grout formulations and selected metal-in-grout formulations.
An overview of near-field evolution research in support of the UK geological disposal programme
Authors: Beattie T. M. , Williams S. J. 
Published: January 2013

AbstractThe near field, together with the containment and isolation provided by the geosphere, contributes to the long-term safety provided by a geological disposal facility (GDF) after closure. The different engineered barriers can prevent or limit the release of radionuclides and their migration to the undisturbed host rock or geosphere and are expected to fulfil their post-closure safety functions for many thousands to hundreds of thousands of years. They will continue to contribute to containment after their eventual degradation when there would no longer be confidence that they would continue to fulfil all of their safety functions in their totality. By that time, significant radioactive decay will have occurred, substantially reducing the hazard associated with the wastes. Therefore, demonstration of long-term safety requires an understanding of the evolution of the engineered barriers and the consequences for the generic safety functions that the different barriers provide. This paper provides an overview of the research of the Nuclear Decommissioning Authority Radioactive Waste Management Directorate into the evolution of the near field of a GDF.