bluuebunny/crossref_metadata_2025_split huggingface dataset:
Re-cold expansion process simulation to impart the residual stresses around fastener holes in 6061 A-T6 aluminium alloy
Authors: Jang J S , Kim D W 
Published: November 2008

Cold expansion processes are widely used in aerospace structures to eliminate or delay fatigue crack nucleation and to improve fatigue life. Fastener holes, in which the fatigue cracks initiate from stress concentrations, are plastically expanded using a mandrel pulled through the hole. Cold expansion technology has been applied to enhance low-cycle fatigue performance in repair as well as production applications. Repair of aircraft structures is a key component to extend aircraft service life. Re-cold expansion process conditions such as the degree of cold expansion should be determined to impart the beneficial compressive residual stresses around the holes under tensile loadings. In this paper, a process simulation using three-dimensional finite element analysis is conducted to determine the residual stress imparted by re-cold expansion in the fastener holes under the external loading conditions. Three levels of re-cold expansion under three external loading levels are performed in this numerical investigation. It is shown that the re-cold expansion process with at least 6 per cent of the degree of cold expansion imparts deep residual stresses around the hole so that the resulting stress levels on the hole entry side remain compressive under applied external stress levels between 100 and 200 MPa. In addition, residual stress redistribution under various applied external stresses is discussed.
Thermal model of a twin-tube cavitating shock absorber
Authors: Alonso M , Comas Á 
Published: November 2008

An analytical method to quantify the damping force of a generic twin-tube shock absorber for an automobile is proposed. Previous models by the present authors have accounted for fluid compressibility, chamber deformation, and fluid cavitation. This paper extends the work to thermal effects which have now been included. The variation in the force due to thermal effects caused by the energy dissipated within the damper is determined and the shock absorber temperature field is calculated. The results from the model are compared with those from simpler models (which do not include thermal effects) and are validated against the results from a real shock absorber. In terms of damping force, a good correlation is obtained, while acceptable results are obtained for the temperature field calculation.
Development of a direct-injection stratified-charge methanol engine
Authors: Li B-Z , Liu S-H , Nong J-J , Gong Y-F , Zhou L-B 
Published: November 2008

On the basis of the wall-guided, spray-guided, and air-guided technologies related to gasoline direct-injection spark-ignition (DISI) engines, a complex-guided stratified-charge combustion system for a methanol DISI engine was developed. The test engine was a retrofitted four-cylinder diesel engine. The key parameters were optimized numerically and experimentally, such as the location of the swirl deflector, the spatial location of spray, the swirl ratio, the injection and ignition timings, and the needle valve opening pressure. The results show that the direct-injection stratified-charge (DISC) methanol engine can work with an excessive air ratio λ as high as 2.23, and its brake thermal efficiency reaches 29.7 per cent at a speed of 1500r/min, and a brake mean effective pressure of 0.45MPa. The DISC methanol engine exhibits relatively good performance with little cyclic variations, although it is sensitive to induction swirl. The test results indicate that the matching principle is successful. The developed DISC methanol engine can run under variable induction swirl to meet the requirement of stratification combustion under different engine speed operating conditions.
In situ and on-demand lubrication by tribo-coating for space applications
Authors: Adachi K , Kato K 
Published: November 2008

A self-restoring lubrication system with an in situ and on-demand controllable lubrication method is required to improve reliability and to overcome unexpected tribological problems in space. A new type of lubrication method called ‘tribo-coating’, which forms a thin lubricious film (tribo-coating film) in nanometre-scale by vacuum deposition during sliding, is promising as a required lubrication method for future space systems. This method gives the unique advantage of excellent tribological performance of friction coefficient of<0.02 in sliding contacts and 0.002 in ball bearings. Its possibility as a self-restored lubrication system with in situ and on-demand control of lubrication for ball bearings in vacuum systems is clarified.
Analysis Method of Trace Compounds by Hollow-fiber Liquid-phase Microextraction with Electric Field Enhancement of Mass Transfer
Authors: Guo Yugao , Yu Yuzan , Liu Xiujun , Tang Enqi 
Published: November 2008

Abstract
A novel electric-field-enhanced liquid-phase microextraction system based on hollow fiber membrane has been developed. By introducing the radially enhancing electric field into this system, it is feasible to accelerate the mass-transfer rate of analyte and shorten the equilibrium time. In the process, the extract time was less than 4 min, which is much less than that of traditional liquid-phase microextraction. Further study is in progress.
Direct Preparation and Size Control of Highly Crystalline Cubic ITO Nanoparticles in a Concentrated Solution System
Authors: Endo Yosuke , Sasaki Takafumi , Kanie Kiyoshi , Muramatsu Atsushi 
Published: November 2008

Abstract
Highly crystalline cubic indium tin oxide (ITO) nanoparticles with narrow size distribution were successfully prepared directly in one step from a mixed solution of indium and tin salts by a solvothermal method with ethylene glycol as solvent. Also, size was easily manipulated by changing conditions, such as aging period and sodium hydroxide concentration.
Resonance-enhanced Multiphoton Ionization Spectroscopy of the S1–S0 Transition of Benzo[e]pyrene for Real-time Analysis
Authors: Misawa Kentaro , Matsumoto Jun , Tsuji Norihiro , Matsuzaki Yoichi , Hayashi Shun-ichi , Fujii Masaaki 
Published: November 2008

Abstract
The electronic spectrum of benzo[e]pyrene (BeP) was recorded using resonance-enhanced multi-photon ionization (REMPI) spectroscopy. A number of bands were observed and assigned to the origin band and vibronic bands of the S1–S0 transition. Ab initio calculations were performed to assign the vibrational structures in S1. The origin band of BeP is well separated in energy from the origin band of benzo[a]pyrene (BaP), an isomer of BeP, and so BeP and BaP can be readily distinguished by the REMPI method, despite having the same mass.
Siloxane-crosslinked Polysaccharide Nanogels for Potential Biomedical Applications
Authors: Yamane Setsuko , Sasaki Yoshihiro , Akiyoshi Kazunari 
Published: November 2008

Abstract
The hybrid nanogels were prepared by condensation of silanol groups grafted to cholesterol-bearing pullulan at ambient temperature and pH without any catalysts or organic solvents. This is a new method for preparation of organic–inorganic hybrid nanogels with dual network structures of both chemically crosslinked points with siloxane bonds and physically crosslinked hydrophobic association points.
Spillover Asymmetry and Why It Matters
Authors: Knott Anne Marie , Posen Hart E. , Wu Brian 
Published: November 2008

Although spillovers are a crucial factor in determining the optimal environment for innovation, there is no consensus regarding their impact on firm behavior. One reason for this may be that models differ in their assumptions for the functional form of the spillover pool. In industrial organization and economic geography, for example, the predominant convention is that all innovation within an industry/region contributes to a spillover pool that has a common value for all firms. An alternative convention prevalent in endogenous growth and evolutionary economics is that spillovers have directionality—the size of the relevant pool differs across firms. Knowing the correct functional form may facilitate theoretical consensus, either analytically (by modifying models' assumptions) or empirically (by supporting a critical test of competing theories). We characterize and test the functional form of spillover pools for efficiency-enhancing innovation across 50 markets in the banking industry. Our results in that setting are consistent with expectations for asymmetric spillovers but inconsistent with expectations for pooled spillovers.
Hybrid Films Consisting of a Clay and a Diacetylenic, Two-Photon Absorptive Dye
Authors: Suzuki Yasutaka , Hirakawa Shoichiro , Sakamoto Yusuke , Kawamata Jun , Kamada Kenji , Ohta Koji 
Published: November 2008

AbstractHybrid films consisting of Sumecton SA smectite (SSA) and a diacetylenic two-photon absorptive dye; 1,4-bis(2,5-dimethoxy-4-{2-[4-(N-methyl)pyridinium]ethenyl}phenyl) butadiyne triflate (MPPBT) were fabricated. The MPPBT-clay composites were prepared by the cation exchange method in a dimethylsulfoxide (DMSO)-water mixed solvent. A low-light-scattering film, suitable for use in optical devices, was obtained by filtration of the dispersion of the MPPBT-clay composites. Estimation of the two-photon absorption cross-section (σ(2)) by means of the open-aperture Z-scan technique was performed using the present film. The σ(2) value of MPPBT in the film fabricated at the MPPBT loading levels vs. 20% cation exchange capacity was 1030 GM (1 GM= 1 × 1050 cm4 s photon−1 molecule−1) at an excitation wavelength of 800 nm. The value was 1.3 times greater than the maximum value of the σ(2) of MPPBT diss lved in DMSO with ut clay.
Adsorption of Protamine and Papain Proteins on Saponite
Authors: Szabó Tamás , Mitea Raluca , Leeman Hugo , Premachandra Gnanasiri S. , Johnston Cliff T. , Szekeres Márta , Dékány Imre , Schoonheydt Robert A. 
Published: November 2008

AbstractDue to the increased importance of bionanocomposites, protamine and papain proteins were adsorbed on Na+- and on Cs+-exchanged saponite from aqueous solution. Protein analysis of equilibrium solutions and thermogravimetric analyses of biocomposites were used to prepare adsorption isotherms. Based on the isotherm shape, and on the amounts of protein adsorbed and the amounts of Na+ and Cs+ released, the initial protein sorption apparently was due to ion exchange. Additional sorbed protein was weakly retained and could be removed by washing with water. From ion exchange, the average charge of the protamine adsorbed was estimated to be +13.1 to +13.5. Similar papain measurements could not be made due to partial decomposition. Quantitatively, protamine was adsorbed at levels up to 400 mg/g on Na+-saponite and 200 mg/g on Cs+-saponite. The maximum protamine adsorption was 650 to 700 mg/g for Na+-saponite and 350–400 mg/g for Cs+-saponite. Protamine was sorbed to edge surfaces and the basal spacing of the interlamellar region of saponite was 1.75 nm. Protamine displaced only 36% of the Cs+ in Cs+-saponite and expanded the interlamellar region by 36% for a basal spacing of 1.6 nm. Papain sorption to Na+-saponite occurred by a two-step process: (1) adsorption to saponite particle external surfaces followed, (2) by partial intercalation. Quantitatively, Papain was adsorbed up to 100 mg/g for Na+-and Cs+-saponite. Greater initial papain concentrations resulted in a 450 mg/g maximum for Na+-saponite, but no increase above 100 mg/g for Cs+-saponite. Papain apparently only sorbed to external Cs+-saponite surfaces that were estimated to be 33–40 m2/g. Step-wise thermal decomposition of the saponite-protein composites occurred between 300 and 800°C.
Thermodynamic Properties of Feroxyhyte (δ′-FeOOH)
Authors: Majzlan Juraj , Koch Christian Bender , Navrotsky Alexandra 
Published: November 2008

AbstractFeroxyhyte (δ′-FeOOH) is a relatively uncommon Fe oxide mineral and one of the few phases in the system Fe2O3-H2O for which thermodynamic properties are not known. In natural occurrences, it is always fine-grained, although samples with larger particle sizes and better crystallinity (labeled as δ-FeOOH) can be prepared in the laboratory. This contribution presents a thermochemical study on a series of feroxyhyte samples. One is fine-grained and poorly crystalline, similar to natural materials, while the other three are of better crystallinity. The enthalpy of formation of feroxyhyte at 298.15 K is −547.4±1.3kJ mol−1 for the poorly crystalline sample (surface area 88 m2/g), and −550.6±1.4, −550.9±1.3, and −552.6±1.2 kJ mol−1 for the samples with better crystallinity. The entropy of feroxyhyte can be estimated only crudely, because it is influenced to a great extent by its magnetic properties, particle size, and structural disorder. The S298o$S_{298}^{\rm{o}}$ of feroxyhyte is estimated here to be 65±5 J K−1 mol−1. The Gibbs free energy of the reaction feroxyhyte → hematite + liquid water is −7.4 to −12.6 kJ mol−1 at 298.15 K. The Gibbs free energy of formation (ΔGfo${\rm{\Delta }}G_{\rm{f}}^{\rm{o}}$) of the fine-grained, poorly crystalline feroxyhyte is −478.1±2.0 kJ mol−1 at 298.15 K. Since this sample is closest in its physical properties to natural feroxyhyte, this ΔGfo${\rm{\Delta }}G_{\rm{f}}^{\rm{o}}$ value should be used in thermodynamic modeling related to processes involving naturally occurring feroxyhyte. In terms of Gibbs free energy and enthalpy, feroxyhyte is very similar to lepidocrocite and maghemite, and, like these two phases, has no thermodynamic stability field in the system Fe2O3-H2O, except possibly at the nanoscale.
Contemporary Pedogenic Formation of Palygorskite in Irrigation-Induced, Saline-Sodic, Shrink-Swell Soils of Maharashtra, India
Authors: Hillier S. , Pharande A. L. 
Published: November 2008

AbstractIncreasing use of irrigation in India has exacerbated the problems of soil salinity and sodicity. The present study was undertaken on shrink-swell soils from Maharastra State to determine if changes in soil chemistry due to irrigation have affected the clay mineralogy. Twenty six samples (15 locations) of irrigation-induced, saline-sodic, shrink-swell soils and 27 samples (22 locations) of normal un-irrigated (rain-fed) shrink-swell soils were studied using X-ray powder diffraction (XRPD), infrared spectroscopy (FTIR), and scanning and transmission electron microscopy (SEM, TEM). The XRPD analysis of the <0.2 µm fraction of rain-fed, shrink-swell soils indicates a predominance of dioctahedral smectite with minor to trace amounts of kaolinite and chlorite. Traces of palygorskite (1–4%) were detected in three samples. In contrast, palygorskite is a common component (1–20%) of the fine-clay fraction of saline-sodic soils. Quantitative analysis of palygorskite by XRPD in whole-soil (<2 mm) samples showed that saline-sodic soils contain up to 20 wt.% of palygorskite, whereas palygorskite was only detectable (1.5 wt.%) in one sample of the rain-fed set. The SEM, TEM, and FTIR confirm the presence of Fe-rich palygorskite in saline-sodic soils and demonstrate that the fibrous palygorskite crystals are exceedingly small (∼0.5 µm long). Delicate palygorskite fibers radiate from the margins of smectite plates suggestive of a pedogenic origin and a close genetic relationship between smectite and palygorskite. The compositions of saturation-paste extracts display a shift from the stability field of smectite in rain-fed soils to that of palygorskite in saline-sodic soils. Thus the occurrence and formation of palygorskite appears to be related to the change in land management from rain-fed to irrigated agriculture. This change has occurred over a period of no more than 40–50 y, implying that palygorskite formation in the irrigated, saline-sodic soils has been an extremely rapid process.
Smectite Clay Sequestration of Aflatoxin B1: Particle Size and Morphology
Authors: Mulder I. , Barrientos Velazquez A. L. , Tenorio Arvide M. G. , White G. N. , Dixon J. B. 
Published: November 2008

AbstractThe properties that might influence the sequestration of aflatoxin B1 (AfB1) were examined. Laser-diffraction, particle-size analysis (LDPSA) indicated that the particle size of the smectite influences the amount of AfB1 adsorbed. Effective adsorbent smectites disperse well under combined sodium hexametaphosphate solution and ultrasonic agitation. Particle size explained 66% of the variability for most of the samples investigated in an ‘as-received’ state. One effective adsorbent smectite was especially well aggregated and required additional physical dispersion, thus raising the correlation to 73%. Transmission electron microscope (TEM) images show typical smectites and reveal the very diverse morphology of smectites in bentonites. Thin, cloud-like smectite, in TEM images, related positively to AfB1-adsorption capacity. Particles that often fold and are usually ∼0.5 µm across seem to be optimal. The selection of criteria for evaluating these smectites provides a scientific basis for their selection to obtain reliable performance. Particle size is of particular importance as outlined below, and use of LDPSA makes it possible to perform the analysis efficiently and with precision.
Mineralogy and Genesis of Smectites in an Alkaline-Saline Environment of Pantanal Wetland, Brazil
Authors: Furquim Sheila Aparecida Correia , Graham Robert C. , Barbiero Laurent , de Queiroz Neto José Pereira , Vallès Vincent 
Published: November 2008

AbstractSmectite formation in alkaline-saline environments has been attributed to direct precipitation from solution and/or transformation from precursor minerals, but these mechanisms are not universally agreed upon in the literature. The objective of this work was to investigate the mineralogy of smectites in the soils surrounding a representative alkaline-saline lake of Nhecolândia, a sub-region of the Pantanal wetland, Brazil, and then to identify the mechanisms of their formation.Soils were sampled along a toposequence and analyzed by X-ray diffraction, transmission electron microscopy-energy dispersive X-ray analysis, and inductively coupled plasma-mass spectrometry. Water was collected along a transect involving the studied toposequence and equilibrium diagrams were calculated using the databases PHREEQC and AQUA.The fine-clay fraction is dominated by smectite, mica, and kaolinite. Smectites are concentrated at two places in the toposequence: an upper zone, which includes the soil horizons rarely reached by the lake-level variation; and a lower zone, which includes the surface horizon within the area of seasonal lake-level variation. Within the upper zone, the smectite is dioctahedral, rich in Al and Fe, and is classified as ferribeidellite. This phase is interstratified with mica and vermiculite and has an Fe content similar to that of the mica identified. These characteristics suggest that the ferribeidellite originates from transformation of micas and that vermiculite is an intermediate phase in this transformation. Within the lower zone, smectites are dominantly trioctahedral, Mg-rich, and are saponitic and stevensitic minerals. In addition, samples enriched in these minerals have much smaller rare-earth element (REE) contents than other soil samples. The water chemistry shows a geochemical control of Mg and saturation with respect to Mg-smectites in the more saline waters. The REE contents, water chemistry, and the presence of Mg-smectite where maximum evaporation is expected, suggest that saponitic and stevensitic minerals originate by chemical precipitation from the water column of the alkaline-saline lake.
Evaporation of Pesticide Droplets on Surfaces Under Various Relative Humidity Conditions
Authors: Yu Y. , Zhu H. , Ozkan H. E. 
Published: November 2008

Abstract
It is important to understand the evaporation process of pesticide droplets on targets for increasing the efficiency and efficacy of foliar applied insecticide and fungicide spray applications. Evaporation characteristics of five droplet sizes (246, 343, 575, 762, and 886 μm) under three relative humidity (RH) conditions (30, 60, and 90 %) were studied in a laboratory. Sequential images of evaporating droplets placed inside a small environmentally controlled chamber were obtained using a stereoscope for determination of droplet evaporation time and residual patterns. The spray mixtures included different combinations of water, a nonionic colloidal polymer drift retardant, an alkyl polyoxyethylene surfactant, and an insecticide. The droplet evaporation was investigated on the surfaces of hydrophilic and hydrophobic glass slides which represented ideal non-waxy and waxy leaf surfaces, respectively. Among the spray mixtures investigated, the droplets containing the drift retardant had the longest evaporation time, and the droplets containing the surfactant had the shortest evaporation time after these additives were added into insecticide mixtures. The mean evaporation time of 246, 343, 575, 762, and 886 μm droplets containing water and the insecticide without additives at 60 % RH on the hydrophilic surface were 43, 77, 133, 226, and 384 s, respectively. The mean evaporation times of the same size droplets containing the same insecticide but mixed with the surfactant were 26, 47, 77, 156, and 251 s, respectively. The evaporation time of 575 μm droplets containing the drift retardant at 60 % RH increased from 159 s to 224 s when the deposition surface changed from the hydrophilic slide to the hydrophobic slide. The evaporation time of droplets greatly increased as RH increased, and also increased exponentially as the droplet size increased. Therefore, spray additives, target surface fine structure and RH greatly influenced the evaporation time of spray droplets.
Actinide binding by Kläui ligands: REDOX speciation and sorption on an extraction chromatography resin
Authors: Levitskaia Tatiana G. , Sinkov Sergey I. , Lumetta Gregg J. 
Published: November 2008

AbstractThe sorption of Eu(III) and actinide ions in various oxidation states from nitric acid solutions by an extraction chromatography resin containing 1 wt. % of the Kläui ligand Cp*Co[P(O)(OR)2]3−[Cp*=pentamethylcyclopentadienyl, R=–CH2CH2CH3] on Amberlite®XAD-7HP was examined. At 0.3 M HNO3and a metal-to-ligand ratio of 0.07, the relative affinity of the resin for the ions investigated followed the order: tetravalent»hexavalent>trivalent>pentavalent; however, the relative affinity for the trivalent and hexavalent ions can be reversed, depending on the extent of ligand loading and the nitric acid concentration. The sorption of the tetravalent ions was exceptionally strong in the entire range of nitric acid concentration examined (0.2 to 8 M HNO3). The large difference in the affinity of the resin with the Kläui ligand for tetravalent actinides compared to hexavalent actinides is unusual for ligands with the P=O donor moiety.Resin samples loaded with various actinide ions were examined spectrophotometrically. No Np(V) and Pu(III) species were identified on the resin; rather, reduction–oxidation (REDOX) reactions occurred during equilibration, resulting in their complete conversion to M(IV) species bound by the Kläui ligand. Similarly, the sorption behavior of Pu(VI) and Np(VI) was complicated by their reduction to M(IV) upon sorption. The observed REDOX processes were apparently driven by the extremely high affinity of the Kläui ligand for the tetravalent ions. The acid–base properties of the methyl derivative of the Kläui ligand were investigated in aqueous solution, and its pKawas found to be highly dependent upon the solution ionic strength. The binding constants of this ligand with various actinide ions measured in a mixed methanol/carbon tetrachloride solvent exhibited qualitative agreement with the sorption selectivity trends.