bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐Density Periodically Ordered Magnetic Cobalt Ferrite Nanodot Arrays by Template‐Assisted Pulsed Laser Deposition
Authors: Gao Xingsen , Liu Lifeng , Birajdar Balaji , Ziese Michael , Lee Woo , Alexe Marin , Hesse Dietrich 
Published: August 2009

AbstractA novel nanopatterning method using pulsed laser deposition through an ultrathin anodic aluminium oxide (AAO) membrane mask is proposed to synthesize well‐ordered nanodot arrays of magnetic CoFe2O4 that feature a wide range of applications like sensors, drug delivery, and data storage. This technique allows the adjustment of the array dimension from ∼35 to ∼300 nm in diameter and ∼65 to ∼500 nm in inter‐dot distance. The dot density can be as high as 0.21 Terabit in.−2. The microstructure of the nanodots is characterized by SEM, TEM, and XRD and their magnetic properties are confirmed by well‐defined magnetic force microscopy contrasts and by hysteresis loops recorded by a superconducting quantum interference device. Moreover, the high stability of the AAO mask enables the epitaxial growth of nanodots at a temperature as high as 550 °C. The epitaxial dots demonstrate unique complex magnetic domains such as bubble and stripe domains, which are switchable by external magnetic fields. This patterning method creates opportunities for studying novel physics in oxide nanomagnets and may find applications in spintronic devices.
Stimuli‐Responsive Thin Coatings Using Elastin‐Like Polymers for Biomedical Applications
Authors: Costa Rui R. , Custódio Catarina A. , Testera Ana M. , Arias Francisco J. , Rodríguez‐Cabello José C. , Alves Natália M. , Mano João F. 
Published: August 2009

AbstractSmart thin coatings using a recombinant elastin‐like polymer (ELP) containing the cell attachment sequence arginine–glycine–(aspartic acid) (RGD) are fabricated for the first time through simple deposition of the ELP dissolved in aqueous‐based solutions. The biopolymer is produced and characterized using electrophoresis and mass spectroscopy. The temperature and pH responsiveness are assessed by aggregate size measurements and differential scanning calorimetry. The deposition of the studied ELP onto chitosan is followed in situ with a quartz‐crystal microbalance with dissipation monitoring (QCM‐D). Contact angle measurements are performed at room temperature and at 50 °C, showing reversible changes from a moderate hydrophobic behavior to an extremely wettable surface. AFM analysis performed at room temperature reveals a smooth surface and no organized structure. At 50 °C, the surface presents spherical nanometer‐sized structures of collapsed biopolymer chains. Such results suggest that the ELP chains, when collapsed, aggregate into micelle‐like structures at the surface of the substrate, increasing its water affinity. Cell adhesion tests on the developed coatings are conducted using a SaOS‐2 cell line. Enhanced cell adhesion could be observed in the H‐RGD6‐coated surfaces, as compared with the original chitosan monolayer. An intermediate behavior is found in chitosan coated with the corresponding ELP without the RGD sequence. Therefore, the developed films have great potential as biomimetic coatings of biomaterials for different biomedical applications, including tissue engineering and controlled delivery of bioactive agents. Their thermo‐responsive behavior can also be exploited for tunable cell adhesion and controlled protein adsorption.
Synthesis of Hexagonal Yb3+,Er3+‐Doped NaYF4 Nanocrystals at Low Temperature
Authors: Schäfer Helmut , Ptacek Pavel , Eickmeier Henning , Haase Markus 
Published: August 2009

AbstractNanocrystals of NaYF4 doped with Yb3+ and Er3+ are synthesized in oleylamine using Y2(CO3)3, Yb2(CO3)3, Er2(CO3)3, Na2CO3, and NH4F as precursors. In contrast to other starting materials normally used for such syntheses, these precursors react even at room temperature to form hexagonal‐phase (β‐phase) NaYF4:Er,Yb nanoparticles. Cubic‐phase (α‐phase) NaYF4:Yb,Er particles are formed only at elevated temperatures (>250 °C). The formation of the cubic phase at high temperatures can be suppressed by replacing pure oleylamine with oleic acid/oleylamine mixtures. Under optimized reaction conditions, particles with an average particle size of about 7 nm are generated in 84% yield. Heat treatment (30 min, 280 °C) of the particles significantly increases the luminescence efficiency. A transparent solution of the heat‐treated, nanometer‐sized phosphor in toluene shows intense visible light emission upon excitation in the near infrared.
Effect of Alkyl Side‐Chain Length on Photovoltaic Properties of Poly(3‐alkylthiophene)/PCBM Bulk Heterojunctions
Authors: Gadisa Abay , Oosterbaan Wibren D. , Vandewal Koen , Bolsée Jean‐Christophe , Bertho Sabine , D'Haen Jan , Lutsen Laurence , Vanderzande Dirk , Manca Jean V. 
Published: August 2009

AbstractThe morphological, bipolar charge‐carrier transport, and photovoltaic characteristics of poly(3‐alkylthiophene) (P3AT):[6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) blends are studied as a function of alkyl side‐chain length m, where m equals the number of alkyl carbon atoms. The P3ATs studied are poly(3‐butylthiophene) (P3BT, m = 4), poly(3‐pentylthiophene) (P3PT, m = 5), and poly(3‐hexylthiophene) (P3HT, m = 6). Solar cells with these blends deliver similar order of photo‐current yield (exceeding 10 mA cm−2) irrespective of side‐chain length. Power conversion efficiencies of 3.2, 4.3, and 4.6% are within reach using solar cells with active layers of P3BT:PCBM (1:0.8), P3PT:PCBM (1:1), and P3HT:PCBM (1:1), respectively. A difference in fill factor values is found to be the main source of efficiency difference. Morphological studies reveal an increase in the degree of phase separation with increasing alkyl chain length. Moreover, while P3PT:PCBM and P3HT:PCBM films have similar hole mobility, measured by hole‐only diodes, the hole mobility in P3BT:PCBM lowers by nearly a factor of four. Bipolar measurements made by field‐effect transistor showed a decrease in the hole mobility and an increase in the electron mobility with increasing alkyl chain length. Balanced charge transport is only achieved in the P3HT:PCBM blend. This, together with better processing properties, explains the superior properties of P3HT as a solar cell material. P3PT is proved to be a potentially competitive material. The optoelectronic and charge transport properties observed in the different P3AT:PCBM bulk heterojunction (BHJ) blends provide useful information for understanding the physics of BHJ films and the working principles of the corresponding solar cells.
Non‐Close‐Packed Crystals from Self‐Assembled Polystyrene Spheres by Isotropic Plasma Etching: Adding Flexibility to Colloid Lithography
Authors: Plettl Alfred , Enderle Fabian , Saitner Marc , Manzke Achim , Pfahler Christian , Wiedemann Stefan , Ziemann Paul 
Published: August 2009

AbstractHexagonally ordered arrays of non‐close‐packed nanoscaled spherical polystyrene (PS) particles are prepared exhibiting precisely controlled diameters and interparticle distances. For this purpose, a newly developed isotropic plasma etching process is applied to extended monolayers of PS colloids (starting diameters <300 nm) deposited onto hydrophilic silicon. Accurate size, shape, and smoothness control of such particles is accomplished by etching at low temperatures (−150 °C) with small rates not usually available in standard reactive ion etching equipment. The applicability of such PS arrays as masks for subsequent pattern transfer is demonstrated by fabricating arrays of cylindrical nanopores into Si.
Nonstationary fault detection and diagnosis for multimode processes
Authors: Liu Jialin , Chen Ding‐Sou 
Published: August 2009

AbstractFault isolation based on data‐driven approaches usually assume the abnormal event data will be formed into a new operating region, measuring the differences between normal and faulty states to identify the faulty variables. In practice, operators intervene in processes when they are aware of abnormalities occurring. The process behavior is nonstationary, whereas the operators are trying to bring it back to normal states. Therefore, the faulty variables have to be located in the first place when the process leaves its normal operating regions. For an industrial process, multiple normal operations are common. On the basis of the assumption that the operating data follow a Gaussian distribution within an operating region, the Gaussian mixture model is employed to extract a series of operating modes from the historical process data. The local statisticT2and its normalized contribution chart have been derived for detecting abnormalities early and isolating faulty variables in this article. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Thermal and mass transients in the developing region of a homogeneous tubular chemical reactor
Authors: Alkam Mohammad K. , Darwish Feras H. , Almuhtasib Aziz A. 
Published: August 2009

AbstractThe current investigation presents a finite difference simulation of a homogeneous tubular reactor under laminar flow conditions. The present simulation considers the unsteady operation where transients in flow hydrodynamics, temperature field, and species concentrations have been considered. Flow development in the entrance region of the present reactor has been considered. Present results exhibit reactant concentration and mixing cup temperature profiles for a variety of operating conditions. Effects of several parameters on the performance of the current reactor have been examined, including, reaction parameter, order of reaction, and Schmidt number. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Optimal design of single‐contaminant regeneration reuse water networks with process decomposition
Authors: Bai Jie , Feng Xiao , Deng Chun 
Published: August 2009

AbstractWater network with regeneration schemes (e.g., regeneration reuse, regeneration recycling) can reduce freshwater consumption further than water network merely with direct reuse. Regeneration reuse, compared with regeneration recycling, can additionally avoid unexpected accumulation of contaminants. Owing to these features, process decomposition can help to reduce freshwater usage and wastewater discharge of regeneration reuse water systems and achieve the results, which graphical method delivers. In this article, the effect of decomposition on water‐using process and further on regeneration reuse water system is briefly analyzed on the concentration‐mass load diagram. Then a superstructure and three sequential mathematical models, which take process decomposition into account, are in turn developed to optimize single contaminant regeneration reuse water systems. By several examples, the reliability of the models is verified. Moreover, several decomposition strategies are summarized to realize the regeneration reuse water network, which attains the targets from graphical method. The results indicate that postregeneration concentration has a major impact on the scheme of process decomposition. © 2009 American Institute of Chemical Engineers AIChE J, 2009
An engineering‐purpose preparation strategy for ammonium‐type ionic liquid with high purity
Authors: Sun Xiaoqi , Ji Yang , Liu Yu , Chen Ji , Li Deqian 
Published: August 2009

AbstractA new strategy for preparing ammonium‐type ionic liquid (IL) by acid/base neutralization reaction was proposed. The method contributed to preparing hydroxide‐based ammonium IL and resulting task specific ionic liquid (TSIL) with high purity using a low‐costly and environment‐friendly synthetic route. Halide contamination in the prepared ILs could be markedly decreased than those prepared by well‐established anion metathesis method. Moreover, some novel TSILs composed of cations and anions with big steric hindrances could be prepared by this method. Physicochemical properties of the bifunctional TSILs, i.e., density, water content, decomposition temperature, and munal solubility, were also studied in this article. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Possibilities and challenges in occupational injury surveillance of day laborers
Authors: Lowry Sarah J. , Blecker Hillary , Camp Janice , De Castro Butch , Hecker Steven , Arbabi Saman , Traven Neal , Seixas Noah S. 
Published: August 2009

AbstractBackgroundDay laborers in the US, comprised largely of undocumented immigrants from Mexico and Central America, suffer high rates of occupational injury according to recent estimates. Adequate surveillance methods for this highly transient, largely unregulated group do not currently exist. This study explores chart abstraction of hospital‐based trauma registry records as a potential injury surveillance method for contingent workers and day laborers. We sought to determine the degree of completeness of work information in the medical records, and to identify day laborers and contingent workers to the extent possible.MethodsWork‐related injury cases from a hospital‐based trauma registry (2001–2006) were divided by ethnicity (Hispanic vs. non‐Hispanic origin) and presence of social security number (SSN: yes, no), resulting in four groups of cases. Medical records were abstracted for 40 cases from each group; each case was assigned values for the variables “day labor status” (yes, no, probably not, probable, unknown) and “employment type” (contingent, formal, unknown).ResultsWork information was missing for 60% of Hispanic cases lacking SSN, as compared with 33–47% of the other three groups. One “probable” day laborer was identified from the same group. Non‐Hispanics with SSN were less frequently identified as contingent workers (5% as compared with 15–19%).ConclusionsThis method revealed severe limitations, including incomplete and inconsistent information in the trauma registry and medical records. Approaches to improve existing resources for use in surveillance systems are identified. The potential of an active surveillance approach at day labor hiring centers is also briefly discussed. Am. J. Ind. Med. 53:126–134 2010. © 2009 Wiley‐Liss, Inc.
Are employment shifts into non‐manufacturing industries partially responsible for the decline in occupational injury rates?
Authors: Morse Tim F. , Deloreto Albert , St. Louis Thomas , Meyer John D. 
Published: August 2009

AbstractBackgroundBureau of Labor Statistics figures have shown declines in injury and illness rates over the past 25 years. It is unclear what factors are contributing to that decline.MethodsConnecticut injury and illness data was industry‐adjusted to account for the shifts in employment by industry sector for the 25‐year period from 1976 to 2000. Additional adjustment was made for manufacturing sub‐sectors, since declines in manufacturing employment accounted for the largest proportion of the shift in injuries over that period.ResultsApproximately 18% of the decline in injury and illness rates was associated with a shift in employment from more hazardous to less hazardous industries. Shifts in manufacturing sub‐sectors accounted for an additional 5.7% of the decline.ConclusionA significant proportion of the decline in injury and illness rates appears to be due to demographic shifts in industry composition. Am. J. Ind. Med. 52:735–741, 2009. © 2009 Wiley‐Liss, Inc.
Preparation and in vitro degradation of novel bioactive polylactide/wollastonite scaffolds
Authors: Xu Liang , Xiong Zuo Chun , Yang Dejuan , Zhang Li Fang , Chang Jiang , Xiong Cheng Dong 
Published: August 2009

AbstractComposite scaffolds for applications in bone engineering from poly(D,L‐lactide) (PDLLA) incorporated with different proportional bioactive wollastonite powders were prepared through a salt‐leaching method, using NH4HCO3 as porogen. The pore structures and morphology of the scaffolds were determined by scanning electron microscopy (SEM). The bioactivity of composite materials was evaluated by examining its ability to initiate the formation of hydroxyapatite (Ca10(PO4)6(OH)2)(HAp) on its surface when immersed in simulated body fluids (SBF). The in vitro degradation behaviors of these scaffolds were systematically monitored at varying time periods of 1, 2, 4, 6, 8, 11, 14, 17, 20, 24, and 28 weeks postimmersion in SBF at 37°C. FT‐IR, XPS, XRD, and SEM measurements revealed that hydroxyapatite commenced to form on the surface of the scaffolds after 7 days of immersion in SBF. The measurements of weight loss, pH, and molecular weight of the samples indicated that PDLLA/wollastonite composite scaffolds degraded slower than the pure PDLLA scaffolds do. Addition of wollastonite enhanced the mechanical property of the composite scaffolds. The in vitro osteoblast culture experiment confirmed the biocompatibility of the scaffold for the growth of osteo‐blasts. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009.
Mechanical and thermal properties of functionalized multiwalled carbon nanotubes and multiwalled carbon nanotube–polyurethane composites
Authors: Chen Xianhong , Wang Jianfeng , Zou Jiagui , Wu Xiaoli , Chen Xiaojin , Xue Feng 
Published: August 2009

AbstractMultiwalled carbon nanotube (MWNT)–polyurethane (PU) composites were obtained by an in situ polycondensation approach. The effects of the number of functional groups on the dispersion and mechanical properties were investigated. The results showed that the functionalized MWNTs had more advantages for improving the dispersion and stability in water and N,N′‐dimethylformamide. The tensile strength and elongation at break of the composites exhibited obvious increases with the addition of MWNT contents below 1 wt % and then decreases with additions above 1 wt %. The maximum values of the tensile strength and elongation at break increased by 900 and 741%, respectively, at a 1 wt % loading of MWNTs. Differential scanning calorimetry measurements indicated that the addition of MWNTs resulted in an alteration of the glass‐transition temperature of the soft‐segment phase of MWNT–PU. Additionally, new peaks near 54°C were observed with differential scanning calorimetry because of the microphase‐separation structures and alteration of the segment molecular weights of the hard segment and soft segment of PU with the addition of MWNTs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthetic paper from plastic waste: Influence of a surface treatment with corona discharge
Authors: Santana R. M. Campomanes , Manrich S. 
Published: August 2009

AbstractPolymers generally have a chemically inert surface, are nonporous, and have low surface energy, which is characterized by their relatively weak adhesion to other materials. Numerous methods have been developed to modify polymer surfaces chemically. This study was an investigation of how the surface energy of synthetic paper (composite film) could be altered after treatment by corona discharge and of the stability of the surface energy of a film produced from postconsumer polypropylene (PP). A PP/filler (70/30 w/w) composite film was processed in a single‐screw extruder with a flat‐film dye. In this study, the film stretching rate and electric charge potential of the film surface treatment were the process parameters analyzed. The results showed that the conditions of the surface treatment by corona discharge and the presence of a filler (calcium carbonate) influenced some surface properties: the contact angle, surface energy, and ink adhesion. The surface energy of the composite film increased from 38.7 × 10−3 N/m2 without treatment to 52.3 × 10−3 N/m2 with treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Incorporation of triclosan into polydioxanone monofilaments and evaluation of the corresponding release
Authors: Blanco M. G. , Franco L. , Puiggalí J. , Rodríguez‐Galán A. 
Published: August 2009

AbstractPoly(p‐dioxanone) monofilaments were loaded with triclosan, a drug with a well‐known antimicrobial effect. Two different procedures were considered: loading by molecular diffusion with a swelling solvent such as dichloromethane and loading by means of a coating based on polycaprolactone or polycaprolactone/magnesium stearate mixtures. Triclosan release was studied in different media by high‐performance liquid chromatography. The kinetics of loading by diffusion and the release from both kinds of preparations were evaluated with well‐established models. In general, the first stages of the loading process fit with the Higuchi approximation, whereas the final stages fit with the first‐order model. The last model could be applied to predict the release behavior. A sustained release over a period that could reach 400 h was attained when ethanol was added to the release medium, whereas equilibrium conditions were reached when Sörensen's hydrophilic medium was used. Significant differences in the release profiles of a Sörensen's/ethanol medium were observed, which depended on the loading methodology. Thus, an 80% release was attained after 36 h for a polycaprolactone‐coated sample and after 80–100 h for a sample loaded by diffusion. Degradation studies of the triclosan‐loaded samples were also performed because the increase in the hydrophobicity of the samples could hinder the hydrolytic degradation. The weight‐average molecular weight of unloaded and loaded (29,075 μg/g) sutures dropped to 220.000 and 110.000 after 45 days of exposure to the medium at 37°C, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Microwave absorbing properties of ternary linear low‐density polyethylene/carbonyl iron powder/carbon black composites
Authors: Shen Xiang‐Zhong , Xie Shan‐Mei , Guo Jun , Liu Zhi‐Cheng 
Published: August 2009

AbstractLinear low‐density polyethylene (LLDPE) was used as polymer matrix, carbonyl iron powder (CIP) and carbon black (CB) were used as fillers, and ternary composites with microwave absorbing properties were prepared by melt blending. Transmission electron microscopy was used to characterize the prepared samples. The absorbing ability (reflection loss) of the prepared composites was measured using the arch method, and the electromagnetic parameters of composites were determined by the transmission/reflection method. The filler contents of CIP and CB have effects on the absorbing peak positions and reflection loss, and there is the optimum filler content in composites to obtain the maximum microwave absorbing. The microwave absorption of LLDPE/CIP/CB composites comes from the combining contributions of the dielectric loss and the magnetic loss. The synergistic effects of CIP and CB effectively improve the microwave absorbing properties of polymer composites. CIP and CB are uniformly distributed in the polymer matrix. The theoretical calculation results of the absorbing ability are in agreement with the experimental results using the transmission line theory. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of novel organosoluble polyesters based on a DIOL with azaquinoxaline ring
Authors: Ghaemy M. , Mighani H. , Ziaei P. 
Published: August 2009

AbstractA series of new polyesters were synthesized by polycondensation of aliphatic and aromatic dicarboxylic dichlorides with a novel quinoxaline diol, 2,3‐bis (4‐hydroxy phenyl)‐5‐azaquinoxaline (DIOL). The DIOL was synthesized by reacting 4,4′‐dihydroxy benzil with 2, 3‐diaminopyridine (yield: 85%), and characterized by FTIR and 1H‐NMR spectra. All polyesters showed good solubility in most aprotic polar solvents such as NMP (N‐methylpyrrolidone), DMF (dimethylformamide), DMSO (dimethylsulfoxide), DMAc (dimethylacetamide), HMPA (hexamethylenephosphoramide), and Py (pyridine). The inherent viscosity of polyesters was obtained in the range of 1.1–1.22 dL/mg. The glass transition temperatures of the polyesters were in the range of 200–280°C, as determined by DSC. The initial decomposition temperatures of the polyesters were above 300°C and the char yield at 750°C ranged from 30 to 60% under nitrogen atmosphere. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009