bluuebunny/crossref_metadata_2025_split huggingface dataset:
The morphology, mechanical properties, and flammability of aligned electrospun polycarbonate (PC) nanofibers
Authors: Moon SungCheal , Farris Richard J. 
Published: July 2008

AbstractThe electrospinning of the polycarbonate (PC) solutions was performed for the variable electrospinning parameters such as polymer concentration, solvent composition, applied voltage, flow rate, and take‐up velocity in order to evaluate changes of morphology, mechanical properties, and flammability of the aligned PC nanofibers as a function of the electrospinning parameters. It was found that the ratio of THF/DMF solvent in the electrospinning parameters had a major effect on the spinnability and fiber morphology. Furthermore, it was confirmed that the mechanical properties were dependent upon the fiber morphology. The spinnability of the PC solutions with a lower THF ratio in THF/DMF solvent was poor. The aligned electrospun PC fiber with the best morphology was made in the range of polymer concentration of 22%, solvent ratio of 50:50 THF : DMF, applied voltage of 14 kV, flow rate of 0.050 ml/m, and a take‐up velocity of 7.3 m/s. The ultimate strength and initial modulus of the 80% drawn 22% PC fiber were 64 ± 2 MPa (commercial 55–75 MPa) and 1.9 ± 0.1 GPa. The heat release capacity (HRC) of the 22 and 25% PC fiber were 275 ± 27 J/g K and 198 ± 1 J/g K. It was found that the flame resistance of the electrospun PC nanofiber was superior to that of the PC raw material (HRC ∼360 J/g K). POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Uniaxial tensile properties underlying plane‐stress rapid fracture resistance in polyethylene
Authors: Özbek Pemra , Leevers Patrick 
Published: July 2008

AbstractDevelopers of polyethylene grades for pressure pipe seek a deeper understanding of the resistance of these materials to high rate, plane‐stress fracture. The Reversed Charpy and ASTM F 2231 “Thin Charpy” test methods are designed to index this property, at appropriately high rates, for quality control and material development purposes. This article demonstrates the possibility of deriving equivalent information from a procedure based on tensile drawing tests, via two more basic material properties—yield stress and strain hardening modulus—which are more accessible to polymer design. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Rheological characterization of starch derivatives/polycaprolactone blends processed by reactive extrusion
Authors: Bossard Frédéric , Pillin Isabelle , Aubry Thierry , Grohens Yves 
Published: July 2008

AbstractLinear viscoelastic, steady shear behaviors, and morphologies of starch formate/poly(ε‐caprolactone) (PCL) blends, compatibilized by oligomers and obtained by reactive extrusion, have been investigated as a function of formic acid (FA)/starch ratio, nature, and molecular weight of the oligomer. The rheological properties of these blends have been compared with those of a commercial starch‐based thermoplastic, namely Mater‐Bi® ZF03UA. In presence of FA, starch is destructured to starch formate and oligomers are used as plasticizers. The linear viscoelastic response of blends is quite similar to that of nanocomposite materials: the low frequency behavior is attributed to a percolated network of destructured starch particles, and the high frequency behavior is that of the polymer matrix. The viscosity curve presents a profile characterized by two plateau regions, at low and high shear rates. The plateau region at low shear rates corresponds to the viscous response of the blend while that observed at high shear rates can be attributed to the PCL matrix. The compatibilization is enhanced in the presence of starch formate and increases with increasing the oligomer molecular weight. The use of PCL oligomer was shown to improve this compatibilization effect. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Characterization of viscoelastic fluid flow in a periodically driven cavity: Flow structure, frequency response, and phase lag
Authors: Sriram S. , Deshpande Abhijit P. , Pushpavanam S. 
Published: July 2008

AbstractTransport phenomena in periodically driven cavities are important because of their relevance in polymer processing and microfluidics. The transient periodic flow of viscoelastic fluids in a cuboidal cavity, with periodic motion of top plate, was studied in this work. Flow with a characteristic time scale was achieved through the simple harmonic motion of the top plate. The flow in the cavity was characterized by measuring planar velocity fields using particle image velocimetry (PIV). Temporal variation of velocity except at central vertical plane showed predominance of the plate frequency. The temporal point variations, though seemingly similar to those for Newtonian and purely viscous non‐Newtonian fluids, led to rich varieties of spatial flow structures in case of the viscoelastic fluids. The overall flow behavior was characterized using spatial variations, phase trajectories, and streamline patterns. The transition from low Reynolds number steady‐lid driven type flow to complex vortical patterned flow was observed during a cycle of periodic motion of viscoelastic fluids. The effects of elasticity and inertia on the flow fields were analyzed. Computational fluid dynamics simulations with purely viscous shear thinning fluid (power law) and Newtonian fluid showed significant differences with experimental measurements on viscoelastic fluids. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Frequency of the sit‐to‐stand task: a pilot study of free‐living adults
Authors: Kerr Andy , Dall Philippa , Ryan Cormac 
Published: July 2008

AbstractPurpose. To report contemporary data on the daily frequency of the sit‐to‐stand (STS) movement in a healthy, independently living, adult population. Relevance. As a key determinant of functional independence, which has a high mechanical load, the STS movement is a common feature of rehabilitation. Knowledge of STS frequency during daily activities could inform rehabilitation goals and content, but has rarely been examined. To date, only McLeod et al. (1975) have investigated this, reporting an average of 92 daily STS transitions in healthy young participants. Methods. Fifteen healthy, free‐living, ambulant adults (three males; mean age 40 years) were recruited from the general population. An activity monitor (activPALTM, PALtechnologies, Glasgow, UK) reported free‐living activity for each subject for seven consecutive days. Analysis. The average number of STS transitions per day was calculated from the whole period. Data were separated into working and non‐working days, and compared using a paired t‐test. Results. On average, participants performed 64 (±19) STS movements each day, with large individual differences [range 35–105]. Participants performed significantly (p = 0.047) more STS movements on a working day [68 (±24)] than on a non‐working day [55 (±17)]. Discussion. Fewer STS movements were recorded than previously reported (McLeod et al., 1975). This may reflect general changes in lifestyle; however, comparisons should consider the small samples involved and methodological differences. Conclusion. This study provides contemporary data for STS frequency and demonstrates a significant difference between working and non‐working days. This information could guide rehabilitation and future research. Copyright © 2008 John Wiley & Sons, Ltd.
Curcumin has anticonvulsant activity on increasing current electroshock seizures in mice
Authors: Bharal Nidhi , Sahaya Kinshuk , Jain Seema , Mediratta Pramod K. , Sharma Krishna K. 
Published: July 2008

AbstractEpilepsy is one of the most common serious disorders of the brain. Several experimental studies have reported neuroprotective and antioxidant activity of certain natural products like curcumin, an active ingredient of turmeric. The present study was designed to explore the effect of acute administration of curcumin at doses 50, 100 and 200 mg/kg, orally (p.o.) and its chronic (× 21 days) administration in 100 mg/kg, p.o. on increasing current electroshock (ICES) test, elevated plus maze and actophotometer in mice. Curcumin in a dose of 100 mg/kg significantly increased the seizure threshold in ICES test on both acute and chronic administration. The same dose of 100 mg/kg on acute administration showed anxiogenic effect on elevated plus maze and actophotometer test. However, this anxiogenic effect of curcumin disappeared on chronic administration. These results suggest that curcumin appears to possess anticonvulsant activity in mice. Copyright © 2008 John Wiley & Sons, Ltd.
Imaging G‐SIMS: a novel bismuth‐manganese source emitter
Authors: Green Felicia M. , Kollmer Felix , Niehuis Ewald , Gilmore Ian S. , Seah Martin P. 
Published: July 2008

AbstractG‐SIMS (gentle‐SIMS) is a powerful method that considerably simplifies complex static secondary ion mass spectrometry (SSIMS) analysis of organics at surfaces. G‐SIMS uses two primary ion beams that generate high and low fragmentation conditions at the surface. This allows an extrapolation to equivalent experimental conditions with very low fragmentation. Consequently, the spectra are less complex, contain more structural information and are simpler to interpret. In general, G‐SIMS spectra more closely resemble electron ionisation mass spectra than SSIMS spectra. A barrier for the wider uptake of G‐SIMS is the requirement for two ion beams producing suitably different fragmentation conditions and the need for their spatial registration (spatial alignment) at the surface, which is especially important for heterogeneous samples. The most popular source is the liquid metal ion source (LMIS), which is now sold with almost every new time‐of‐flight (TOF)‐SIMS instrument. Here, we have developed a novel bismuth‐manganese emitter (the ‘G‐tip’) for the popular LMISs. This simplifies the alignment and gives excellent G‐SIMS imaging and spectroscopy without significantly compromising the bismuth cluster ion beam performance. © Crown copyright 2008. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
A practical approach to robotic design for the DARPA Urban Challenge
Authors: Patz Benjamin J. , Papelis Yiannis , Pillat Remo , Stein Gary , Harper Don 
Published: July 2008

AbstractThis article presents a practical approach to engineering a robot to effectively navigate in an urban environment. Inherent in this approach is the use of relatively simple sensors, actuators, and processors to generate robot vision, intelligence, and planning. Sensor data are fused from multiple low‐cost, two‐dimensional laser scanners with an innovative rotational mount to provide three‐dimensional coverage with image processing using both range and intensity data. Information is combined with Doppler radar returns to yield a world view processed by a context‐based reasoning control system to yield tactical mission commands forwarded to traditional proportional‐integral‐derivative (PID) control loops. As an example of simplicity and robustness, steering control successfully utilized a relatively simple follow‐the‐carrot guidance approach that has been successfully demonstrated at speeds of 60 mph (97 km/h). The approach yielded a robot that reached the finals of the Urban Challenge and completed approximately 2 h of the event before being forced to withdraw as a result of a global positioning system data failure. © 2008 Wiley Periodicals, Inc.
Team Cornell's Skynet: Robust perception and planning in an urban environment
Authors: Miller Isaac , Campbell Mark , Huttenlocher Dan , Kline Frank‐Robert , Nathan Aaron , Lupashin Sergei , Catlin Jason , Schimpf Brian , Moran Pete , Zych Noah , Garcia Ephrahim , Kurdziel Mike , Fujishima Hikaru 
Published: July 2008

AbstractTeam Cornell's Skynet is an autonomous Chevrolet Tahoe built to compete in the 2007 DARPA Urban Challenge. Skynet consists of many unique subsystems, including actuation and power distribution designed in‐house, a tightly coupled attitude and position estimator, a novel obstacle detection and tracking system, a system for augmenting position estimates with vision‐based detection algorithms, a path planner based on physical vehicle constraints and a nonlinear optimization routine, and a state‐based reasoning agent for obeying traffic laws. This paper describes these subsystems in detail before discussing the system's overall performance in the National Qualifying Event and the Urban Challenge. Logged data recorded at the National Qualifying Event and the Urban Challenge are presented and used to analyze the system's performance. © 2008 Wiley Periodicals, Inc.
Autonomous driving in urban environments: Boss and the Urban Challenge
Authors: Urmson Chris , Anhalt Joshua , Bagnell Drew , Baker Christopher , Bittner Robert , Clark M. N. , Dolan John , Duggins Dave , Galatali Tugrul , Geyer Chris , Gittleman Michele , Harbaugh Sam , Hebert Martial , Howard Thomas M. , Kolski Sascha , Kelly Alonzo , Likhachev Maxim , McNaughton Matt , Miller Nick , Peterson Kevin , Pilnick Brian , Rajkumar Raj , Rybski Paul , Salesky Bryan , Seo Young‐Woo , Singh Sanjiv , Snider Jarrod , Stentz Anthony , Whittaker William “Red” , Wolkowicki Ziv , Ziglar Jason , Bae Hong , Brown Thomas , Demitrish Daniel , Litkouhi Bakhtiar , Nickolaou Jim , Sadekar Varsha , Zhang Wende , Struble Joshua , Taylor Michael , Darms Michael , Ferguson Dave 
Published: July 2008

AbstractBoss is an autonomous vehicle that uses on‐board sensors (global positioning system, lasers, radars, and cameras) to track other vehicles, detect static obstacles, and localize itself relative to a road model. A three‐layer planning system combines mission, behavioral, and motion planning to drive in urban environments. The mission planning layer considers which street to take to achieve a mission goal. The behavioral layer determines when to change lanes and precedence at intersections and performs error recovery maneuvers. The motion planning layer selects actions to avoid obstacles while making progress toward local goals. The system was developed from the ground up to address the requirements of the DARPA Urban Challenge using a spiral system development process with a heavy emphasis on regular, regressive system testing. During the National Qualification Event and the 85‐km Urban Challenge Final Event, Boss demonstrated some of its capabilities, qualifying first and winning the challenge. © 2008 Wiley Periodicals, Inc.
Magnetization‐induced optical second harmonic generation from the surface of Co‐doped rutile TiO2(110)
Authors: Watanabe R. , Yuasa M. , Yahata Y. , Mizutani G. , Suzuki T. , Segawa Y. , Matsumoto Y. , Yamamoto Y. , Koinuma H. 
Published: July 2008

AbstractWe have investigated the surface magnetism of 5 at% Co‐doped rutile TiO2(110) using magnetization‐induced optical second harmonic generation (MSHG) in the longitudinal Kerr configuration with the incident beam angle of 4° . MSHG is observed at both 2ħω = 2.33 eV and 2ħω = 4.20 eV. MSH intensity showed a hysteresis as a function of the external magnetic field for the second harmonic photon energy of 2ħω = 4.20 eV at which the absorption length limits the MSHG origin to the surface layer of 10 nm due to the TiO2 bulk. Since 5 at% Co: TiO2(110) is judged to have no metallic Co near the top surface by XPS, the hysteresis is attributed to a carrier‐induced ferromagnetism at the surface of this material. Copyright © 2008 John Wiley & Sons, Ltd.
First‐principles study of the (001) surface of cubic PbTiO3
Authors: Zhang Jian‐Min , Pang Qing , Xu Ke‐Wei , Ji Vincent 
Published: July 2008

AbstractWe present first‐principles calculations on the (001) surfaces of cubic PbTiO3 with PbO and TiO2 terminations. The cleavage energy, surface energy, surface grand potential, surface relaxation and surface electronic structure have been investigated by using the projector‐augmented wave method under generalized gradient approximation (GGA). The results show that surface energy of a TiO2‐terminated surface is a little lower than that of a PbO‐terminated one, thus allowing both terminations to coexist. The PbO‐termination is stable in O‐ and Pb‐rich environments, while on the contrary, the TiO2‐termination is stable in O‐ and Pb‐poor conditions. In addition, the surface rumpling S of a PbO‐terminated surface is slightly larger than that of a TiO2‐terminated one. The relaxations dominantly take place on the outermost three layers, and an oscillatory (− + −) damping (|Δd12 | > | Δd23 | > | Δd34|) relaxation phenomenon appears for both terminations. The band gaps of both PbO‐ and TiO2‐terminations are slightly lower than that of the bulk. Moreover, the DOS curves of each layer show that for the TiO2‐termination, the top of the valence band of the first and third TiO2 layers moves toward Fermi level. Copyright © 2008 John Wiley & Sons, Ltd.
A survey of nurses who experienced trauma in the workplace: influence of coping strategies on traumatic stress
Authors: Niiyama Etsuko , Okamura Hitoshi , Kohama Akitsugu , Taniguchi Takahide , Sounohara Mitsuhiko , Nagao Mitsushiro 
Published: July 2008

AbstractDecreasing traumatic stress is a key issue for nurses who experience trauma, but trauma of nurses in the workplace has only rarely been investigated in detail. This study was designed to characterize trauma of nurses in the workplace in detail, and to make comparison of coping strategies employed by nurses who recovered from traumatic stress and those of nurses with persistent traumatic stress. A study of trauma was conducted by asking 782 nurses to complete a questionnaire. Valid responses were provided from 592 nurses. Free descriptions of trauma were analysed using the KJ method to characterize the trauma of nurses. A comparison of scores on coping subscales in the persistent trauma group and recovery group was made by the unpaired t‐test. Of the 592 nurses, 301 female nurses had experienced trauma in the workplace. The analysis revealed that 50 nurses (17 per cent) recovered from traumatic stress, while 251 (83 per cent) had persistent traumatic stress. Trauma predominantly consisted of direct exposure to violent language or non‐supportive behaviour by physicians, followed by witnessing and learning of experiences. The results suggested that ‘positive action’, ‘positive thinking’, ‘cognitive avoidance’, ‘uncontrolled thinking’ and ‘talking’ lead to persistence of traumatic stress. Copyright © 2008 John Wiley & Sons, Ltd.
Experiences and results from tailoring and deploying a large process standard in a company
Authors: Armbrust Ove , Ebell Jan , Hammerschall Ulrike , Münch Jürgen , Thoma Daniela 
Published: July 2008

AbstractWith increasing process maturity of the software developing companies, an increasing interest in standardized processes can be observed. Company‐specific standards are often derived from reference standards such as ISO/IEC 12207 or the German V‐Modell XT. Developing and deploying a (new) company‐wide standard is a challenging task with many obstacles. Many efforts in defining and deploying standard processes in a company do not result in sufficient adherence between the defined and the lived (i.e. the enacted) process. Such situations have severe consequences, e.g. it is not possible to measure processes. Published experience with process definition and deployment projects is often anecdotal or incomplete. This paper describes the adaptation of a generic process standard to an organization and its deployment to daily practice. In this article, the approach taken for adapting and deploying the V‐Modell XT in the data processing department of the German Josef Witt GmbH is described. Additionally, effort data and lessons learned with respect to these activities are given. Finally, effects visible so far are sketched. Copyright © 2008 John Wiley & Sons, Ltd.
Using seismic isolation columns for retrofitting buildings with soft stories
Authors: Briman V. , Ribakov Y. 
Published: July 2008

AbstractBase isolation is known as en effective way to improve structural seismic response and reduce damages that may be caused to structures by earthquakes. The objective of seismic isolation is to decouple the structure from the earthquake motion input, preventing the structure from absorbing the earthquake energy. A new engineering solution for seismic isolation columns is presented in this study. It is aimed first of all at retrofitting existing buildings with a soft storey by replacing weak conventional columns, having low static and dynamic load carrying capacity, by the proposed ones. The idea is based on a well known friction pendulum principle. The proposed seismic isolation column is a kinematic system. Its main joint has high load carrying capacity as well as all properties of a three‐dimensial hinge connection. No special materials are required for its manufacturing. No special lifting equipment is required to replace the conventional columns in existing structures by the proposed ones. An additional advantage is that manufacturing of such seismic isolation columns is relatively easy and does not require high accuracy and testing of each unit, like in other types of base isolators. A method for design of buildings, incorporating the proposed devices, was developed. The developed design procedure was applied for a multi‐storey RC frame with infill walls in a numerical example. It was shown that using the proposed solution yields significant improvement in structural response to earthquakes. Copyright © 2008 John Wiley & Sons, Ltd.
The melting temperature (or not melting) of poly(vinyl chloride)
Authors: Summers James W. 
Published: July 2008

AbstractThe best answer to what is the melting temperature of PVC is its previous processing temperature. That temperature is where secondary crystallites, created by gelation, melt and allow the primary particle flow units to flow again independently. In the case of powder compounds being processed for the first time, the question of melting is less relevant. The PVC, out of the polymerizer, contains crystallites that are not completely meltable. The issue is how easily the grains of PVC disperse to primary particle flow units. This property depends on polymerization conditions and the type of processing equipment. The temperature achieved affects the amount of fusion (gelation). J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.
Nanoscopic characterization of a plastisol gelation and fusion process utilizing scanning electron microscopy and atomic force microscopy
Authors: Jourdan Jerome S. , Owen David P. 
Published: July 2008

AbstractUnderstanding the physical properties associated with the gelation and fusion of a PVC plastisol will help to improve process efficiency. Plastisol gelation and fusion were characterized by using both scanning electron microscopy (SEM) and atomic force microscopy (AFM) and were compared with the tensile properties developed at various temperatures. Both SEM and AFM showed good agreement during the early stages of gelation. However, AFM continued to show particle boundaries during the latter stages of gelation and fusion that provided a more nearly accurate comparison with the resulting tensile properties. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.
Landfill degradation of vinyl compositions
Authors: Grossman Richard F. 
Published: July 2008

AbstractThe ideal degradable vinyl compound would disappear into the landfill, forming biomass without toxic contaminants, while evolving gas that could be used for fuel, without the additives used causing loss of processing or service life. The types of additives that might be useful in promoting such behavior are discussed. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.