bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correcting artifacts in transition to a wound optic fiber: Example from high‐resolution temperature profiling in the Dead Sea
Authors: Arnon Ali , Selker John , Lensky Nadav 
Published: June 2014

AbstractSpatial resolution fiber‐optic cables allow for detailed observation of thermally complex heterogeneous hydrologic systems. A commercially produced high spatial resolution helically wound optic fiber sensing cable is employed in the Dead Sea, in order to study the dynamics of thermal stratification of the hypersaline lake. Structured spatial artifacts were found in the data from the first 10 m of cable (110 m of fiber length) following the transition from straight fiber optic. The Stokes and Anti‐Stokes signals indicate that this is the result of differential attenuation, thought to be due to cladding losses. Though the overall spatial form of the loss was consistent, the fine structure of the loss changed significantly in time, and was strongly asymmetrical, and thus was not amenable to standard calibration methods. Employing the fact that the cable was built with a duplex construction, and using high‐precision sensors mounted along the cable, it was possible to correct the artifact in space and time, while retaining the high‐quality of data obtained in the early part of the cable (prior to significant optical attenuation). The defect could easily be overlooked; however, reanalyzing earlier experiments, we have observed the same issue with installations employing similar cables in Oregon and France, so with this note we both alert the community to this persistent concern and provide an approach to correct the data in case of similar problems.
Validating the Rice neural network and the Wing Kp real‐time models
Authors: Bala Ramkumar , Reiff Patricia 
Published: June 2014

AbstractThe Rice neural network models of Kp have been running in real time at http://mms.rice.edu/realtime/forecast.html since October 2007; Dst and AE models were added to our operations in May 2010. All these models use the Boyle index as basis functions computed from ACE real time inputs. Later, two more driving functions were included in November 2012: (a) the “Ram” functions that had dynamic pressure term added to the Boyle index and (b) the Newell functions. The Wing models are a set of neural network‐based Kp forecast models adopted by NOAA/Space Weather Prediction Center in March 2011 to supersede the Costello Kp model. This study indicates that any of the three Rice neural net predictors had a better success rate than the Wing model in predicting Kp (r=0.828 with Boyle, r=0.843 with Ram, and r=0.820 with Newell for 1 h predictions; similarly, r=0.739, 0.769, and 0.755 for 3 h predictions) in real time. In a head‐to‐head challenge using harvested real‐time outputs between April 2011 and February 2013, the Rice Boyle Kp models predicted better than the Wing models (0.771 versus 0.714 for 1 h predictions and 0.770 versus 0.744 for 3 h predictions). In addition, Wing's prediction was missing more often than the Rice prediction (≈6% versus 4.6%), meaning it had less reliability. The Rice models also predict AE(r=0.811 with Boyle; 0.806 with Ram; 0.765 with Newell, and 0.743 with Boyle; 0.747 with Ram for 1 h and 3 h predictions) and pressure‐corrected Dst (r=0.790; 0.767, and 0.704, and r=0.795; 0.797 and 0.707 for 1 h and 3 h predictions).
Understanding sickness presenteeism through the experience of immigrant workers in a context of economic crisis
Authors: Galon Tanyse , Briones‐Vozmediano Erica , Agudelo‐Suárez Andrés A. , Felt Emily B. , Benavides Fernando G. , Ronda Elena 
Published: June 2014

BackgroundPrevious economic recessions show that immigrant workers may experience longer periods of unemployment, a situation that may lead employees to presenteeism, the act of working in spite of a health problem. This study explored perceptions about the factors that lead to presenteeism in immigrant workers considering the context of economic crisis.MethodsSix focus group discussions were held (February 2012), with men and women from Colombia, Ecuador, and Morocco (n = 44) living in Spain and selected by theoretical sample. A qualitative content analysis was performed.ResultsFour categories were identified as factors that influence the occurrence of presenteeism in a context of economic crisis: poor employment conditions, fear of unemployment, employer/employee relationship, and difficulties in finding temporary replacement workers. Furthermore, musculoskeletal, respiratory, and mental problems were related to presenteeism.ConclusionsIt is important to develop strategies to protect workers from negative working conditions that are associated with deterioration of health. Am. J. Ind. Med. 57:950–959, 2014. © 2014 Wiley Periodicals, Inc.
Evaluation of a pilot promotora program for Latino forest workers in southern Oregon
Authors: Bush Diane E. , Wilmsen Carl , Sasaki Timothy , Barton‐Antonio Dinorah , Steege Andrea L. , Chang Charlotte 
Published: June 2014

BackgroundForest work, an occupation with some of the highest injury and illness rates, is conducted primarily by Latino immigrant workers. This study evaluates a pilot program where promotoras (lay community health educators) provided occupational health and safety trainings for Latino forest workers.MethodsEvaluation methods included a focus group, post‐tests, and qualitative feedback.ResultsCommunity capacity to address working conditions increased through (i) increased leadership and community access to information and resources; and (ii) increased worker awareness of workplace health and safety rights and resources. Fear of retaliation remains a barrier to workers taking action; nevertheless, the promotoras supported several workers in addressing‐specific workplace issues.ConclusionsFor working conditions to significantly improve, major structural influences need to be addressed. A long‐term, organizationally supported promotora program can play a key role in linking and supporting change at the individual, interpersonal and community levels, contributing to and supporting structural change. Am. J. Ind. Med. 57:788–799, 2014. © 2014 Wiley Periodicals, Inc.
High Diastereoselection of a Dissymmetric Capsule by Chiral Guest Complexation
Authors: Tsunoda Yuta , Fukuta Katsunori , Imamura Taisuke , Sekiya Ryo , Furuyama Taniyuki , Kobayashi Nagao , Haino Takeharu 
Published: June 2014

AbstractEncapsulation of chiral guests in the dissymmetric capsule 1⋅4 BF4 formed diastereomeric supramolecular complexes G⊂1⋅4 BF4 (G: guest). When chiral guests 2 a–q were encapsulated within the dissymmetric space of the self‐assembled capsule 1⋅4 BF4, circular dichroism (CD) was observed at the absorption bands that are characteristic of the π–π* transition of the bipyridine moiety of the capsule, which suggests that the P and M helicities of the capsule are biased by the chiral guest complexation. The P helicity of diastereomeric complex (S)‐2 l⊂1⋅4 BF4 was determined to be predominant, based on CD exciton coupling theory and DFT calculations. The diastereoselectivity was highly influenced by the ester substituents, such that benzyl ester moieties were good for improving the diastereoselectivity. A diastereomeric excess of 98 % was achieved upon the complexation of 2 j. The relative enthalpic and entropic components for the distereoselectivity were obtained from a van’t Hoff plot. The enthalpic components were linearly correlated with the substituent Hammett parameters (σp+). The electron‐rich benzyl ester moieties generated donor–acceptor π–π stacking interactions with the bipyridine moiety, which resulted in a significant difference in energy between the predominant and subordinate diastereomeric complexes.
Enantioselective Catalysis of the Intermolecular [2+2] Photocycloaddition between 2‐Pyridones and Acetylenedicarboxylates
Authors: Maturi Mark M. , Bach Thorsten 
Published: June 2014

AbstractIntermolecular [2+2] photocycloadditions represent the most versatile and widely applicable of photochemical reactions. For the first time, such intermolecular reactions have been carried out in a catalytic fashion using a chiral triplet sensitizer, with high enantioselectivity (up to 92 % ee). The low catalyst loading (2.5–5 mol %) underlines the high efficiency of the process both in terms of reaction acceleration and differentiation of the enantiotopic faces of the substrate. The substrate is anchored to the chiral catalyst through noncovalent interactions (hydrogen bonds), thus providing a chiral environment in which the enantioselective photocycloaddition proceeds. The densely functionalized products present numerous possibilities for further synthetic transformations.
Characterization of polyetheretherketone particle suspensions for electrophoretic deposition
Authors: Clavijo Silvia , Membrives Francisco , Boccaccini Aldo R. , Santillán María J. 
Published: June 2014

ABSTRACTSuspensions of polyetheretherketone (PEEK) using mixture of ethanol and isopropanol as solvent were prepared to carry out PEEK electrophoretic deposition (EPD). The rheological behavior and suspension structure of PEEK particles dispersed in co‐solvents were investigated over a range of pH values (1–10) and shear rates (γ = 101−3 × 102 s−1). These PEEK suspensions generally exhibited a pseudoplastic flow behavior, indicating the occurrence of particle aggregation in the liquid medium. The maximum solids fraction (ϕm) showed an estimated value of ϕm = 2.9 wt %. Using a suspension with 3 wt % PEEK concentration, PEEK coatings on stainless steel substrates were obtained by EPD at constant voltage condition. The influence of the electrolyte conductivity on PEEK EPD from ethanol–isopropanol suspensions was studied. Experimental results showed that high‐conductivity ethanol‐based suspensions yield non‐uniform deposits, while low‐conductivity suspensions resulted in uniform coatings. The difference in the deposition behavior is due to the different pH of the suspensions and the relationship of pH with suspension conductivity. pH = 8 was the optimal value for this system in terms of deposition results. The surfaces of EPD PEEK coatings were homogenous and a qualitatively good adhesion between the PEEK deposits and the substrate was confirmed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40953.
Applying vermiculite‐modified polypropylene film to flexible packaging material
Authors: Fu YaBo , Li DongLi , Xu WenCai , Qi YingQun , Shang Wei , Wu WeiXia , Wang YaJun 
Published: June 2014

ABSTRACTThis article presents a process for preparing organovermiculite by ball‐milling expanded vermiculite (EVMT) in water‐based ethylene vinyl acetate (EVA) latex. In this process, the vermiculite (VMT) is exfoliated to prepare a kind of EVMT/EVA modifying agent, in which EVA serves as both intercalating polymer into VMT and compatibilizer between VMT and polypropylene (PP). During melt blending between EVMT/EVA and PP, shear force exfoliates VMT sheets, dispersing them relatively well in the PP matrix. Compared with raw PP, EVMT‐modified cast polypropylene (CPP) are better when EVMT loading ranged from 0.5 to 1.0%, with improvement in both the strength and toughness of the EVMT/EVA‐modified CPP film. Specifically, tensile strength was increased by 44–54%, yield stress increased by 26%, stress at break increased by 37–43%, energy at break (toughness) increased by 29–34%, oxygen transmission rate decreased by 6.2–12.9%, the water vapor transmission rate was not significantly affected, the peel bond strength of laminated CPP film increased by 18–27%, and the processability and melt flow index (MFI) of EVMT/EVA/PP composites were improved as well. Increasing MFI attributes facilitated the processing and formation of EVMT/EVA/PP. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40954.
Determination of mass transport properties in food/packaging systems by local measurement with Raman microspectroscopy
Authors: Martinez‐Lopez Brais , Chalier Pascale , Guillard Valerie , Gontard Nathalie , Peyron Stephane 
Published: June 2014

ABSTRACTA fast, nondestructive method based on the determination of local concentration profiles in the polymer thickness with Raman microspectroscopy is presented here. It was used to assess the diffusivity of a model molecule (p‐terphenyl) in amorphous polystyrene films at 95°C (2.38 ± 1.08 × 10−17 m2/s). This methodology was validated by comparison with a more classical destructive approach based on the monitoring of the concentration evolution in the whole of the film with gas chromatography (89.4 × 10−17 m2/s). These values were in agreement with data available in the literature for molecules of the same molecular weight and temperature range determined with local measurement and were significantly lower than those determined by global measurement. Raman microspectroscopy was found to be adapted to slow diffusion speeds typically found in high‐barrier polymers; this allowed diffusivity to be obtained long before the equilibrium was reached and, thus, without the need for the partition coefficient. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40958.
Recycling of reactive dye using semi‐interpenetrating polymer network from sodium alginate and isopropyl acrylamide
Authors: Dhanapal V. , Subramanian K. 
Published: June 2014

ABSTRACTA sequence of semi‐interpenetrating polymer network (semi‐IPN) were synthesized by free radical photo copolymerizing acrylic acid and isopropyl acrylamide (NIPAAm) in aqueous sodium alginate (NaAlg). Their structures (FT‐IR), thermal stability (TG/DTG), morphology (SEM), mechanical properties, reactive blue 4 (RB 4) dye adsorption (624 mg/g) and its dying characteristics, reusability of dye and adsorbent were evaluated. TG thermograms of semi‐IPN in air revealed zero order kinetics for initial step thermal degradation with an activation energy of 68.68 kJ/mol. Dye adsorption showed best fit for Langmuir adsorption isotherm and the kinetics followed pseudo‐second‐order model. The water and dye diffusion kinetics followed non‐Fickian mechanism. The changes in thermodynamic parameters namely Gibbs free energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) indicated that the adsorption was spontaneous and exothermic process for RB 4/semi‐IPN system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40968.
Study on the tribological properties of porous sweating PEEK composites under ionic liquid lubricated condition
Authors: Zhu Yanji , Lin Shan , Wang Huaiyuan , Liu Dujuan 
Published: June 2014

ABSTRACTThe tribological behaviors of novel porous Polyetheretherketone (PEEK) composites under 1‐hexyl‐3‐methylimidazolium tetrafluoroborate ionic liquid lubricated condition were investigated. The effect of sliding velocity and applied load on the sweating tribological properties and the stability of lubricating oil film was also studied. Results indicated that when the sliding velocity was 0.69 m/s and the applied load was 250 N, the friction coefficient and wear rate of the ionic liquid lubricated porous sweating activated carbon fiber/polytetrafluoroethene/PEEK composites showed the minimum values, were 0.0197 and 4.145 × 10−15 m3/Nm, respectively. The friction coefficients fluctuated in a narrow range of 0.0162–0.0215. It was found that the porous sweating PEEK composites under ionic liquid lubricated condition showed good low‐friction and antiwear performance, especially under the condition of high sliding velocity and applied load. The formed transfer film due to the tribo‐chemical reaction as well as boundary lubricating film is effective in improving the carrying capacity and antiwear properties of the porous sweating PEEK composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40989.
Kinetic study on free radical grafting of polyethylene with acrylic acid by reactive extrusion
Authors: Zhang Guofang , Zhang Min , Jia Yuxi 
Published: June 2014

ABSTRACTIn the reactive extrusion process for the free radical grafting of acid monomers onto polyethylene, monomer grafting and homopolymerization occur simultaneously and interact with each other. Using an incremental theory, mathematical models of conversions for monomer grafting and homopolymerization were separately constructed to predict the grafting degree, mass of homopolymer and grafting efficiency. Effects of the barrel temperature, initial monomer and initiator concentrations on grafting behaviors were investigated. The barrel temperature and initial monomer concentration were shown to be the main process parameters for controlling the grafting degree. The grafting degree and mass of homopolymer increased significantly with increasing barrel temperature and monomer concentration and increased marginally with increasing initiator concentration. No significant improvement in the grafting efficiency was observed. The predictions of the models are in good agreement with experimental data. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40990.
Effect of orientation and content of carbon based fillers on thermal conductivity of ethylene‐propylene‐diene/filler composites
Authors: Kim Ji‐Hoo , Kim Gue‐Hyun 
Published: June 2014

ABSTRACTIn this study, synthetic graphite, carbon fiber, and carbon nanotube were used as thermal conductive fillers and ethylene‐propylene‐diene (EPDM) as matrix. Oriented EPDM/filler composites were prepared with two‐roll mill, and the effects of orientation and content of carbon based fillers on thermal conductivity and tensile strength of the composites were investigated. Parallel thermal conductivity of the oriented composites is significantly higher than normal thermal conductivity of the oriented composites. Especially, at 31.6% graphite content, parallel thermal conductivity of oriented composites is 7.14 W/mK. Very high thermal conductivity was achieved for oriented EPDM/graphite composites. Orientation of the fillers using two‐roll mill significantly improves the thermal conductivity in the orientation direction. For all the EPDM/filler composites, tensile strength of orientation direction is higher than that of normal direction. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41000.
Die Setzung von Fundamenten auf unterschiedlichen Gründungen mit eingeschränkter Lastausbreitung
Authors: Priebe Heinz J. 
Published: June 2014

AbstractDie Gründung von Fundamenten lässt sich prinzipiell zwischen dem Grenzfall der ‘flachen’ Gründung auf unbehandeltem Untergrund und dem der ‘tiefen’ auf Pfählen einordnen. Im ersten Fall breitet sich die Spannung aus der gesamten Fundamentlast im Baugrund systematisch aus. Es treten mehr oder weniger große Setzungen auf, die zumindest bei kleinen Fundamenten wegen der Spannungsausbreitung mit der Tiefe verhältnismäßig schnell abklingen. Im zweiten Fall leiten Pfähle fast die gesamte Last in Bodenschichten mit hoher Tragfähigkeit ab. Obwohl es zu keiner nennenswerten entlastenden Spannungsausbreitung kommt, sind die Setzungen dann auch bei hoher Last wegen der großen Pfahlsteifigkeit gering.Zwischen diesen Grenzfällen gibt es viele Gründungsarten oder –kombinationen, die in ihrem Setzungsverhalten weniger leicht einzuschätzen sind. Sie reichen von der sogenannten Pfahl‐Plattengründung bis zu bodenverbessernden Maßnahmen. In all diesen Fällen konzentriert sich die Lastabtragung auf den bewehrten oder verbesserten Baugrund unter dem Fundament, aber ein mehr oder weniger großer Teil der Fundamentlast wird auch nach außen auf den unbehandelten Boden abgegeben. Dieser abfließende Teil, nachstehend als Lastausbreitung bezeichnet, lässt sich oft schwer bestimmen. Da er aber eine erhebliche Rolle im Hinblick auf das Setzungsverhalten der Gründung spielen kann, wird hiermit ein brauchbares Berechnungsverfahren vorgestellt, das die jeweilige Lastausbreitung näherungsweise berücksichtigt.The settlement of footings on different kinds of subsoil treatment with reduced load distributionIn principal, the foundation of footings can be ranked between the border case of a shallow foundation on unimproved ground and a deep foundation with piles. In the first case the pressure of the total load spreads systematically in the subsoil. More or less large settlements occur but – at least in the case of small footings – they decrease fairly quickly due to the spreading of the pressure with the depth. In the second case piles transfer the load directly to soil strata with high bearing capacity. Although no notably relieving spreading of pressure occurs settlements are small even at a high load due to the stiffness of the piles.In between these two cases there are many foundation methods or combinations with settlement performances that cannot easily be evaluated. They range from the so‐called pile‐plate foundation to soil improvement below the foundation. In all these cases the load pressure concentrates on the reinforced or improved subsoil under the foundation. However, either more or less of it is delivered to the untreated soil around. This ”escaping” part, hereinafter called “load distribution” is often difficult to be determined. It may, however, be of substantial importance with regard to the settlement behaviour, so this is to introduce a suitable approximation to consider in a settlement calculation the appropriate load distribution.
Ansatz zur Risserkennung in Stahlblechen anhand der Verzerrung von Lamb‐Wellen
Authors: Wagner Tobias , Unglaub Julian , Thiele Klaus 
Published: June 2014

AbstractIn der hier vorgestellten Arbeit wird die Materialermüdung von Stahlproben anhand der Verzerrung von Lamb‐Wellen untersucht. Gekerbte Stahlproben werden zyklisch auf Zug bis zum Bruch im Low‐Cycle‐Fatigue (LCF) belastet. In Abständen von 1000 Lastzyklen wird die Prüfmaschine angehalten. Ein Aktuator regt Lamb‐Wellen bei einzelnen Frequenzen und Frequenzbändern im Bereich von 1 bis 500 kHz an. Nachdem die Lamb‐Wellen die Kerbe durchlaufen haben, werden sie von einem Sensor aufgenommen. Die Auswertung der gemessenen Spektren zeigt, dass die mittlere Amplitude mit zunehmender Materialermüdung kleiner wird. Diese Ergebnisse bieten die Grundlage zur Entwicklung eines möglichst robusten Verfahrens zur Risserkennung. Ein wesentlicher Vorteil eines solchen Ansatzes ist, dass kurz vor der Entstehung sichtbarer Risse die Materialermüdung erkannt werden kann, ohne dass dafür Referenzmessungen des ungeschädigten Bauwerks nötig sind.Lamb‐wave distortion as approach to detect cracks in steel platesThe work presented here examines fatigue of steel specimens based on harmonic‐distortion of Lamb‐waves. Cyclic tension load is applied on notched steel specimens until failure under Low‐Cycle‐Fatigue (LCF) occurs. The fatigue test is interrupted every 1000 load cycles. An actuator excites Lamb‐waves with singular frequencies and frequency bands in a range from 1 to 500 kHz. After the Lamb‐waves passed the notch they are recorded by a sensor. Analysing the spectra shows a declining of the average amplitude with increasing material fatigue. These results provide an approach to develop a robust crack detection methodology. A major advantage of such an approach is the ability to detect cracks at least shortly before they become visible without requiring reference measurements of the undamaged structure.