bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of radioactive particle tracking to indicate shed fouling in the stripper section of a fluid coker
Authors: Sanchez Francisco J. , Granovskiy Mikhail 
Published: September 2012

AbstractThe stripper section of a fluid‐coker consists of a system of baffles (sheds) that enhances the removal efficiency of entrained and adsorbed hydrocarbons from the fluidised coke‐particles. If the particles contain a thin liquid film layer of heavy hydrocarbons, making them excessively ‘wet’ or ‘sticky’, and if they stay in contact with sheds for too long, solid deposits are formed that lead to stripper fouling. Extensive fouling decreases stripping efficiency and liquid product yield and can shorten run‐times between shutdowns. Because of the fouling, the shape of sheds mostly changes by increasing their surfaces thickness. An early indication of that fouling and the ability to follow its development are essential for choosing optimal parameters of the process. The radioactive particle tracking (RPT) method has been tested to determine its applicability to indicate the change in the shape of internals within a fluidised bed reactor when direct observation is impossible. A single radioactive tracer‐particle has been traced in experiments lasting from 2 to 6 h. The experiments were conducted in a lab‐scale, cold‐flow fluidised bed into which a single shed with walls of different thickness was incorporated. This experimental fluidised bed provides intensive solid phase mixing that allows a single tracer‐particle to be located in any place within the reactor. By registering the frequency of the tracer‐particle appearance within a defined internal space surrounding the shed, the shape of shed was reconstructed. The conducted experiments suggest that RPT technique allows for tracking internals' fouling within a fluidised bed reactor. © 2012 Canadian Society for Chemical Engineering
Hydrolysis of imidazole and 2‐chloropyridine under subcritical and supercritical water conditions
Authors: Barrera‐Ventura Carmen , Salvatierra Dolors , Giralt Francesc , Giralt Jaume 
Published: September 2012

AbstractImidazole and 2‐chloropyridine were used as model molecules to investigate the acid hydrolysis kinetics of agrochemicals in high‐temperature water in a batch reactor system at 28 MPa. Pseudo‐first‐order hydrolysis reaction rate constants for the acid hydrolysis of Imidazole and 2‐chloropyridine were determined in the temperature ranges 200–600 and 400–575°C, respectively, at 28 MPa. Rate constants for both compounds increased with temperature with a local maximum observed at around 400°C due to changes in the physical properties of the solvent. Imidazole and 2‐chloropyridine conversions of 0.95 and 0.99999 were respectively attained at the highest temperature after 30 min of reaction. © 2012 Canadian Society for Chemical Engineering
Experimental study of kerosene–water two‐phase flow in a vertical pipe using hot‐film and dual optical probes
Authors: Hamad F. A. , Khan M. K. , Bruun H. H. 
Published: September 2012

AbstractThe local parameters for kerosene–water upward flow are measured in a vertical pipe of 77.8 mm inner diameter at 4200 mm from the inlet (L/D = 54) using hot‐film and dual optical probes. The effect of superficial water velocity and volumetric quality on radial distribution of two‐phase flow parameters is investigated. The results show the following: (i) the profiles of volume fraction and drop frequency are very similar, and increasing superficial water velocity at low volumetric qualities (<18.6%) change the profile from a convex shape with peak at the pipe centreline to uniform then to concave shape with peak near the wall; (ii) the profiles of drop cut chord change from a parabolic shape with peak at centreline for low superficial water velocities to a flat shape at higher superficial water velocity, and the area‐averaged drop diameter decreases with higher superficial water velocities for all volumetric qualities; (iii) velocity profiles for both phases have shapes similar to single phase flow, flatter at higher values of superficial water velocity and volumetric quality and centreline peaked at low superficial water velocities and volumetric qualities; (iv) the slip velocity decreases with radial distance having a peak at centreline and zero values near the wall; (v) introducing kerosene drops into single phase water flow results in a sharp increase in turbulent intensity, particularly at low water velocity, and the difference between the single phase and two‐phase flow turbulence intensities decreases with higher superficial water velocities and (vi) the results show that interfacial area concentration increased with higher volumetric quality and higher number of bubbles thereby increases the contact area between the two phases. © 2012 Canadian Society for Chemical Engineering
Modification of the AMX membrane surface: Temperature dependence of anion exchange equilibrium
Authors: Guesmi Fatma , Hannachi Chiraz , Hamrouni Béchir 
Published: September 2012

AbstractIn order to improve the selectivity of the AMX membrane, a polyethyleneimine (PEI) layer was adsorbed on its surface. Ion exchange isotherms of (Cl−/NO3−), (Cl−/SO42−) and (NO3−/SO42−), using a modified AMX membrane, were established at different temperatures (from 283 to 313 K), with a constant total concentration of 0.3 mol/L and neutral pH. The results obtained with the modified membrane in this range of temperature show that chloride was the most sorbed and the selectivity order was Cl− > NO3− > SO42−. Selectivity coefficients and thermodynamic equilibrium constants, determined for the three binary systems, increased with increasing temperature. These results were compared with those obtained with the unmodified membrane. It was observed that for the modified membrane, the selectivity towards sulphate ion decreased and the modified membrane became more selective towards monovalent anions. Ion exchange equilibrium at temperatures 283, 298 and 313 K of the studied binary systems were found to be endothermic processes.
Limitations in health care access and utilization among long‐term survivors of adolescent and young adult cancer
Authors: Kirchhoff Anne C. , Lyles Courtney R. , Fluchel Mark , Wright Jennifer , Leisenring Wendy 
Published: September 2012

AbstractBACKGROUND:Health care outcomes for long‐term survivors of adolescent and young adult (AYA) cancer were compared with young adults without a cancer history, using the 2009 Behavioral Risk Factor Surveillance System data.METHODS:Eligible participants were 20 to 39 years of age. There were N = 979 who self‐reported a cancer diagnosis between the ages of 15 to 34 years and were at least 5 years from diagnosis (excluding nonmelanoma skin cancer). The remaining 67,216 participants with no cancer history were used as controls. Using multivariable regressions, relative risks and 95% confidence intervals were generated to examine the relationship of survivor status on indicators of poor health care (uninsured, no personal health care provider, no routine care, and avoiding seeing a doctor due to cost). Adjusted proportions were calculated by demographic groups. Results are weighted by Behavioral Risk Factor Surveillance System survey design.RESULTS:Although the proportion uninsured did not differ (21% of survivors vs 23% of controls), AYA survivors reported forgoing care due to cost at higher levels than controls (relative risk = 1.67, 95% CI = 1.44‐1.94). Cost barriers were particularly high for survivors aged 20 to 29 years (44% vs 16% of controls; P < .001) and female survivors (35% vs 18% of controls; P < .001). Survivors reporting poorer health had more cost barriers. Moreover, uninsured survivors tended to report lower use of health care than did controls.CONCLUSIONS:AYA cancer survivors may forgo health care due to cost barriers, potentially inhibiting the early detection of late effects. Expanding health insurance coverage for young cancer survivors may be insufficient without adequate strategies to reduce their medical cost burdens. Cancer 2012. © 2012 American Cancer Society.
Ion Interactions with a New Ditopic Naphthalimide‐Based Receptor: A Photophysical, NMR and Theoretical (DFT) Study
Authors: Mohan Vaisakh , Nijamudheen A. , Das Sudhir Kumar , Sahu Prabhat K. , Kar Usha Pallabi , Rahaman Abdur , Sarkar Moloy 
Published: September 2012

AbstractA new multi‐component chemosensor system comprising a naphthalimide moiety as fluorophore is designed and developed to investigate receptor–analyte binding interactions in the presence of metal and non‐metal ions. A dimethylamino moiety is utilized as receptor for metal ions and a thiourea receptor, having acidic protons, for binding anions. The system is characterized by conventional analytical methods. The absorption and fluorescence spectra of the system consist of a broad band typical for an intramolecular charge transfer (ICT). The effects of various metal‐ion additives on the spectral behavior of the present sensor system are examined in acetonitrile. It is found that among the metal ions studied, alkali/alkaline earth‐metal ions and transition‐metal ions modulate the absorption and fluorescence spectra of the system. As an additional feature, the anion signaling behavior of the system in acetonitrile is studied. A decrease in fluorescence efficiency of the system is observed upon addition of fluoride and acetate anions. Fluorescence quenching is most effective in the case of fluoride ions. This is attributed to the enhancement of the photoinduced electron transfer from the anion receptor to the fluorophore moiety. Hydrogen‐bond interactions between the acidic NH protons of the thiourea moiety and the F− anions are primarily attributed to the fluoride‐selective signaling behavior. Interestingly, a negative cooperativity for the binding event is observed when the interactions of the system are studied in the presence of both Zn2+ and F− ions. NMR spectroscopy and theoretical calculations are also carried out to better understand the receptor–analyte binding.
A better channel coding for a Link‐16 waveform in pulsed‐noise interference
Authors: Kao Chi‐Han 
Published: September 2012

SUMMARYLink‐16 is a tactical data link currently used by North Atlantic Treaty Organization (NATO) countries, the United States and its allies. The Link‐16 waveform features Reed–Solomon codes for channel coding, cyclic code‐shift keying for 32‐ary baseband symbol modulation, minimum‐shift keying for waveform modulation, and frequency hopping for transmission security. In addition to the original errors‐only decoding of Reed–Solomon codes, both an errors‐and‐erasures decoding (EED) and a special concatenated coding are proposed in this paper to determine a better channel coding scheme for a Link‐16 waveform with noncoherent detection in the presence of pulsed‐noise interference (PNI). The investigation is first carried out both analytically and by simulation for the original Link‐16 waveform transmitted over AWGN. It is then accomplished analytically for the proposed waveforms in both AWGN and PNI. The results show that EED achieves the best error rate performance for a Link‐16 waveform in both AWGN and PNI when the signal‐to‐noise ratio is relatively small. When both the signal‐to‐noise ratio is sufficiently large and the fraction active time of PNI is small, the proposed concatenated coding outperforms both EED and errors‐only decoding. Copyright © 2012 John Wiley & Sons, Ltd.
The influence of spatiotemporal variability and adaptations to hypoxia on empirical relationships between soil acidity and vegetation
Authors: Cirkel Dirk Gijsbert , Witte Jan‐Philip M. , van Bodegom Peter M. , Nijp Jelmer J. , van der Zee Sjoerd E. A. T. M. 
Published: September 2012

ABSTRACTSoil acidity is well known to affect the species composition of natural vegetation. The physiological adaptations of plants to soil acidity and related toxicity effects and nutrient deficiencies are, however, complex, manifold and hard to measure. Therefore, generally applicable quantifications of mechanistic plant responses to soil acidity are still not available. An alternative is the semi‐quantitative and integrated response variable ‘indicator value for soil acidity’ (Rm). Although relationships between measured soil pH and Rm from various studies are usually strong, they often show systematic bias and still contain high residual variances. On the basis of a well‐documented national dataset consisting of 91 vegetation plots and a dataset with detailed, within‐plot, pH measurements taken at three periods during the growing season, it is shown that strong spatiotemporal variation of soil pH can be a critical source of systematic errors and statistical noise. The larger part of variation, however, could be explained by the moisture status of plots. For instance, Spearman's rho decreased from 93% for dry plots and 87% for moist plots to 59% for wet plots. The loss of relation between soil pH and Rm in the moderately acid to alkaline range at increasingly wetter plots is probably due to the establishment of aerenchyma‐containing species, which are able to control their rhizosphere acidity. Adaptation to one site factor (oxygen deficit) apparently may induce indifference for other environmental factors (Fe2+, soil pH). For predictions of vegetation response to soil acidity, it is thus important to take the wetness of plots into account. Copyright © 2012 John Wiley & Sons, Ltd.
Domino Reactions Initiated by Enantioselective Cu‐Catalyzed Conjugate Addition
Authors: Galeštoková Zuzana , Šebesta Radovan 
Published: September 2012

AbstractEnantioselective copper‐catalyzed 1,4‐additions of organometallic reagents are useful components of domino reactions. Enolates resulting from such additions readily react with a range of electrophilic reagents, such as aldehydes and acetals, alkyl and allyl halides and halide surrogates, epoxides, imines, nitroalkenes, and α,β‐unsaturated carbonyl compounds. The aim of this review is to give an overview of domino transformations based on Cu‐catalyzed conjugate addition. Special emphasis is placed on the most recent work and also on that utilized in the synthesis of complex target molecules.
A Highly Nucleophilic Multifunctional Chiral Phosphane‐Catalyzed Asymmetric Intramolecular Rauhut–Currier Reaction
Authors: Zhang Xiao‐Nan , Shi Min 
Published: September 2012

AbstractAn asymmetric variant of the intramolecular Rauhut–Currier (RC) reaction can be achieved using a highly nucleophilic multifunctional chiral phosphane; the corresponding cyclopentene and cyclohexene derivatives are produced in moderate to good yields and with good to excellent enantioselectivities.
Mechanisms to limit higher mode effects in a controlled rocking steel frame. 1: Concept, modelling, and low‐amplitude shake table testing
Authors: Wiebe Lydell , Christopoulos Constantin , Tremblay Robert , Leclerc Martin 
Published: September 2012

SUMMARYControlled rocking steel frames have been proposed as an efficient way to avoid the structural damage and residual deformations that are expected in conventional seismic force resisting systems. Although the base rocking response is intended to limit the force demands, higher mode effects can amplify member design forces, reducing the viability of the system. This paper suggests that seismic forces may be limited more effectively by providing multiple force‐limiting mechanisms. Two techniques are proposed: detailing one or more rocking joints above the base rocking joint and providing a self‐centring energy dissipative (SCED) brace at one or more levels. These concepts are applied to the design of an eight‐storey prototype structure and a shake table model at 30% scale. A simple numerical model that was used as a design tool is in good agreement with frequency characterization and low‐amplitude seismic tests of the shake table model, particularly when multiple force‐limiting mechanisms are active. These results suggest that the proposed mechanisms can enable better capacity design by reducing the variability of peak seismic force demands without causing excessive displacements. Similar results are expected for other systems that rely on a single location of concentrated nonlinearity to limit peak seismic loads. Copyright © 2012 John Wiley & Sons, Ltd.
Joint routing and channel assignment algorithms in cognitive wireless mesh networks
Authors: Zhang Guo‐an , Gu Jin‐yuan , Bao Zhi‐hua , Xu Chen , Zhang Shi‐bing 
Published: September 2012

ABSTRACTMultiple channels can increase network capacity by transmitting traffic on different channels in an interference area. To resolve the channel interference problem in cognitive wireless mesh networks, first, a new channel assignment algorithm based on hierarchy interference model for the cognitive wireless mesh networks is proposed in this paper. Second, a distributed capacity and interference based channel assignment and routing algorithm is proposed. Third, an efficient channel diversity based channel allocation algorithm is proposed. The main purpose of this channel allocation algorithm is to maintain the channel diversity in the neighborhood channels. Fourth, a novel joint multi‐path routing and channel assignment algorithm based on path crossing is proposed. On the basis of simulations, results show that compared with the link‐based channel allocation algorithm in wireless multi‐channel networks, the new four algorithms have an obvious advantage in the performance of delay and throughput, and the performance of the joint multi‐path routing and channel assignment algorithm is the best. Lastly, a channel merging algorithm is also proposed in the channel constrained situation. Simulation results also show that, after the implementation of the channel merging algorithm, the network average throughput and delay performance have been further improved significantly. Copyright © 2012 John Wiley & Sons, Ltd.
Operation Characteristic Analysis of a Direct Methanol Fuel Cell System Using the Methanol Sensor‐less Control Method
Authors: Chen C. Y. , Chang C. L. , Sung C. C. 
Published: September 2012

AbstractThe application of methanol sensor‐less control in a direct methanol fuel cell (DMFC) system eliminates most of the problems encountered when using a methanol sensor and is one of the major solutions currently used in commercial DMFCs. This study focuses on analyzing the effect of the operating characteristics of a DMFC system on its performance under the methanol sensor‐less control as developed by Institute of Nuclear Energy Research (INER). Notably, the influence of the dispersion of the methanol injected on the behavior of the system is investigated systematically. In addition, the mechanism of the methanol sensor‐less control is investigated by varying factors such as the timing of the injection of methanol, the cathode flow rate, and the anode inlet temperature. These results not only provide insight into the mechanism of methanol sensor‐less control but can also aid in the improvement and application of DMFC systems in portable and low‐power transportation.
Model verification and evaluation of the rich‐split process modification at an Australian‐based post combustion CO2 capture pilot plant
Authors: Cousins Ashleigh , Cottrell Aaron , Lawson Anthony , Huang Sanger , Feron Paul H.M. 
Published: September 2012

AbstractThe CSIRO is involved in three CO2 capture pilot plants operating at different coal‐fired power stations throughout Australia. The most recently completed of these is the Tarong CO2 capture pilot plant located at Tarong power station, Nanango, Queensland. The first phase of the experimental program with this pilot plant included operation with monoethanolamine (MEA). This involved parametric studies, process modifications, and finally implementation of 24 h operation. Operation of the pilot plant has shown MEA to be effective in capturing CO2 from the flue gas from Tarong Power Station. CO2 capture efficiencies of up to 94%, and regeneration energies as low as 3.6 MJ/kgCO2 have been achieved. The design of the pilot plant was completed using a commercially available process modeling software tool. Results obtained from the pilot plant were then compared to the model predictions including temperature, solvent CO2 loading, and CO2 gas concentration profiles through the absorber column. A good match has been obtained between the modeling and pilot plant data, verifying the software can be used to predict the performance of the pilot plant when operating on MEA. During this project, the rich‐split process modification was also evaluated. The results suggest that the rich‐split modification can achieve some reduction in reboiler duty and a considerable reduction in the condenser duty. The amount of reduction is dependent on plant design, particularly the efficiency of the lean/rich heat exchanger. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Tumors of the cervical sympathetic chain—Diagnosis and management
Authors: Langerman Alexander , Rangarajan Sanjeet V. , Athavale Sanjay M. , Pham Michelle Q. , Sinard Robert J. , Netterville James L. 
Published: September 2012

AbstractBackgroundTumors originating from the cervical sympathetic chain are uncommon but important entities in the differential diagnosis of parapharyngeal space masses.MethodsWe conducted a retrospective review of patients presenting with tumors of the cervical sympathetic chain.ResultsTwenty‐four patients presented between 1994 and 2010. Presenting symptoms were dysphagia (n = 7.29%), neck mass (n = 7.29%), throat fullness (n = 4.17%), and Horner syndrome (n = 2.8%). Although radiologic images showed classic lateral displacement of the carotid arteries in 10 patients (42%), in 9 patients (38%) the radiologic findings demonstrated splaying of the carotid arteries similar to carotid body tumor, and in 5 patients (20%), the findings were indeterminate. Twenty‐one patients underwent surgical removal of the tumors with pathology revealing 10 paragangliomas, 10 schwannomas, and 1 neurofibroma. Horner (57%) and first‐bite (33%) syndromes were the most common complications.ConclusionsAlthough anterolateral displacement of the carotids is suggestive of a sympathetic tumor, absence of these findings does not rule out this entity. To this end, we have included in this review a guide to preoperative radiologic diagnosis of parapharyngeal space lesions. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
Surgical management of inverted papilloma: Approaching a new standard for surgery
Authors: Carta Filippo , Blancal Jean‐Philippe , Verillaud Benjamin , Tran Hugo , Sauvaget Elisabeth , Kania Romain , Herman Philippe 
Published: September 2012

BackgroundInverted papilloma surgery is currently performed primarily with an endoscopic approach, a technique that has a recurrence rate of 12%. However, a recent study reported a recurrence rate of 5% with a strategy based on subperiosteal dissection of the tumor, with limited indications for using an external approach. The aim of this work was to evaluate whether different teams using the same surgical concepts could reproduce the excellent results that were recently reported.MethodsThis study is a retrospective chart review of 71 consecutive patients with inverted papilloma who were treated during the last 10 years.ResultsIn all, 80% of the patients were treated using a purely endoscopic approach. The mean follow‐up period was 31.6 months. The recurrence rate was 3.3% for cases with at least a 12‐month follow‐up.ConclusionsThis work confirms the results described in recent literature and further supports transnasal endoscopic surgery to manage inverted papilloma. © 2012 Wiley Periodicals, Inc. Head Neck 35: 1415–1420, 2013