bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gain‐scheduling control of a rotary inverted pendulum by weight optimization and H∞ loop shaping procedure
Authors: Yubai Kazuhiro , Okuhara Kazunori , Hirai Junji 
Published: January 2008

AbstractGain‐scheduling control is an effective method for use with plants whose dynamics change significantly according to the operating point. The frozen parameter method, a practical gain‐scheduling controller synthesis method, interpolates the controllers designed at prespecified (frozen) operating points according to the current operation point. Hyde and Glover proposed a gain‐scheduling control method in which the H∞ loop shaping procedure is adopted as a controller synthesis method at each operating point. The H∞ loop shaping procedure is based on loop shaping of an open loop characteristic by frequency weights and is known to be effective for plants with bad condition numbers. However, weight selection satisfying the control specifications is a difficult job for a designer. This paper describes the design of suboptimal weights and a controller by means of an algorithm that maximizes the robust stability margin and shapes the open‐loop characteristic into the desired shape at each operating point. In addition, we formulate the weight optimization problem as a generalized eigenvalue minimization problem, which reduces the burden on the designer in weight selection. Finally, we realize a robust, high‐performance control system by scheduling both weights and controllers. The effectiveness of the proposed control system is verified in terms of the achieved robust stability margin and the experimental time responses of a rotary inverted pendulum, which involves strong nonlinear dynamics. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 30–40, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20647
Reactivity of [M(η4‐P2C2tBu2)] (M = Ge, Sn), with tert‐Butylphosphaethyne P≡CtBu: Synthesis, Structural Characterisation and Computational Studies of the Novel Zwitterionic Organophosphorus Cage Compounds [MP4C4tBu4] (M = Ge, Sn)
Authors: Francis Matthew D. , Hitchcock Peter B. , Nixon John F. , Nyulászi László 
Published: January 2008

AbstractTreatment of [M(η4‐P2C2tBu2)] with the phosphaalkyne P≡CtBu leads to the formation of the unusual zwitterionic cage compounds [M(P4C4tBu4)] (M = Ge, Sn) which have been fully characterised in solution by multinuclear NMR spectroscopy and the solid‐state structure of [GeP4C4tBu4] has been elucidated by a single‐crystal X‐ray diffraction study. DFT calculations support the zwitterionic formulation and suggest the likely reaction pathway. Whilst [GeP4C4tBu4] exhibits considerable stability, [SnP4C4tBu4] shows gradual decomposition in solution within a matter of hours. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A transport‐distance approach to scaling erosion rates: 3. Evaluating scaling characteristics of Mahleran
Authors: Wainwright John , Parsons Anthony J. , Müller Eva N. , Brazier Richard E. , Powell D. Mark , Fenti Bantigegne 
Published: January 2008

AbstractIn the two previous papers of this series, we demonstrated how a novel approach to erosion modelling (Mahleran – Model for Assessing Hillslope‐Landscape Erosion, Runoff And Nutrients) provided distinct advantages in terms of process representation and explicit scaling characteristics when compared with existing models. A first evaluation furthermore demonstrated the ability of the model to reproduce spatial and temporal patterns of erosion and their particle‐size characteristics on a large rainfall‐simulation plot. In this paper, we carry out a more detailed evaluation of the model using monitored erosion events on plots of different size. The evaluation uses four plots of 21·01, 115·94, 56·84 and 302·19 m2, with lengths of 4·12, 14·48, 18·95 and 27·78 m, respectively, on similar soils to the rainfall‐simulation plot, for which runoff and erosion were monitored under natural rainfall. Although the model produces the correct ranking of the magnitude of erosion events, it performs less well in reproducing the absolute values and particle‐size distributions of the eroded sediment. The implications of these results are evaluated in terms of requirements for process understanding and data for parameterization of improved soil‐erosion models. We suggest that there are major weaknesses in the current understanding and data underpinning existing models. Consequently, a more holistic re‐evaluation is required that produces functional relationships for different processes that are mutually consistent, and that have appropriate parameterization data to support their use in a wide range of environmental conditions. Copyright © 2008 John Wiley & Sons, Ltd.
Discussion: Misrepresentation of the USLE in ‘Is sediment delivery a fallacy?’
Authors: Kinnell P. I. A. 
Published: January 2008

AbstractThe assertion that the application of the USLE to predicting soil losses within a catchment or watershed is not sound because the USLE provides an estimate of erosion that would be measured if the entire area were divided up into 22·1 m long plots, and the output from them all added together, is incorrect. The slope length factor was derived from data obtained using a wide range of plot lengths and included the 22·1 m length simply to force it to take on a value of 1·0 when the slope length is 22·1 m. The 22·1 m length has no physical significance but the USLE slope length factor has a physical basis when applied to planar and convex hillslopes. The use of sediment delivery ratios when the USLE is applied to concave areas attempts to correct for applying the USLE beyond its design criteria. It fails because, in using the sediment delivery ratios in the prediction sediment delivery, it is incorrectly assumed that sediment delivery ratios de not vary with the amount of sediment entering a zone of deposition.
Long‐term records of dissolved organic carbon flux from peat‐covered catchments: evidence for a drought effect?
Authors: Worrall F. , Burt T. P. , Adamson J. 
Published: January 2008

AbstractThis study considers three long records of dissolved organic carbon (DOC) flux from two catchments with peat‐covered headwaters. The catchments vary in size from 11 to 818 km2 and the records are at least 12 years old, with one record going back to 1965. The study compares both annual and monthly DOC flux records with a range of hydroclimatic indicators in order to test which component of droughts may contribute to increasing DOC flux. The study found that: (1) there was no significant correlation between any of the proposed drought variables and DOC flux in any of the study catchments over periods of up to 34 years; (2) the most important variable for explaining the DOC flux was the runoff from the catchments overlying a seasonal cycle and an underlying upward trend was present in some records; (3) the residual time‐series, after removal of the best‐fit models, showed no evidence of increased production after times of severe drought. The lack of any evidence for any additional biogeochemical reactions associated with drought supports evidence that DOC loss from peat is limited by its solubility and that its production is fast on the time‐scale of runoff events. Copyright © 2008 John Wiley & Sons, Ltd.
Streamflow scaling properties: investigating characteristic scales from different statistical approaches
Authors: Sauquet Eric , Ramos Maria‐Helena , Chapel Laetitia , Bernardara Pietro 
Published: January 2008

AbstractThis paper studies the links between scaling properties of river flow time series by comparing the results of three techniques applied to an extended data set of 34 French discharge gauging stations. The three approaches used are based on different mathematical tools and hypotheses: (1) shape analysis of flood hydrographs; (2) a multifractal framework through spectral and moment analyses, and (3) flood frequency analysis through the fitting of flood duration frequency curves (QdF). The general aim is to test the hypothesis of scaling invariance of river flow and the shape invariance of the hydrographs, in order to investigate the link between scaling properties and flow dynamics. In particular, the coherence between different approaches widely used in the literature to describe these characteristics is evaluated through the estimation of parameters defining the range of time‐scales on which the scaling properties are valid. The results show that most of these timescale parameters are linked to the flow dynamics and suggest that the approaches applied are interrelated. Copyright © 2008 John Wiley & Sons, Ltd.
Modelling river water temperature using deterministic, empirical, and hybrid formulations in a Mediterranean stream
Authors: Marcé Rafael , Armengol Joan 
Published: January 2008

AbstractRiver water temperature is a common target of water quality models at the watershed scale, owing to its principal role in shaping biogeochemical processes and in stream ecology. Usually, models include physically‐based, deterministic formulations to calculate water temperatures from detailed meteorological information, which usually comes from meteorological stations located far from the river reaches. However, alternative empirical approaches have been proposed, that usually depend on air temperature as master variable. This study explored the performance of a semidistributed water quality application modelling river water temperature in a Mediterranean watershed, using three different approaches. First, a deterministic approach was used accounting for the different heat exchange components usually considered in water temperature models. Second, an empirical approximation was applied using the equilibrium temperature concept, assuming a linear relationship with air temperature. And third, a hybrid approach was constructed, in which the temperature equilibrium concept and the deterministic approach were combined. Results showed that the hybrid approach gave the best results, followed by the empirical approximation. The deterministic formulation gave the worst results. The hybrid approach not only fitted daily river water temperatures, but also adequately modelled the daily temperature range (maximum–minimum daily temperature). Other river water features directly dependent on water temperature, such as river intrusion depth in lentic systems (i.e. the depth at which the river inflow plunges to equilibrate density differences with lake water), were also correctly modelled even at hourly time steps. However, results for the different heat fluxes between river and atmosphere were very unrealistic. Although direct evidence of discrepancies between meteorological drivers measured at the meteorological stations and the actual river microclimate was not found, the use of models including empirical or hybrid formulations depending mainly on air temperature is recommended if only meteorological data from locations far from the river reaches are available. Copyright © 2008 John Wiley & Sons, Ltd.
Hydrogeological interactions between fault zones and alluvial aquifers in regional flow systems
Authors: Folch Albert , Mas‐Pla Josep 
Published: January 2008

AbstractThe hydrological influence of fault zones in tectonic areas is usually difficult to depict from field data. Numerical simulation allows representation of such flow systems and an estimation of flow lines and rates. This paper reports on simulations of the groundwater flow in a range‐and‐basin area affected by a regional fault zone, which may drain or recharge an overlaying alluvial aquifer. Different hydraulic conductivity values for the range rocks, the fault‐zone, and the sedimentary infill of the basin are considered, as well as different fault‐zone widths and boundary conditions. Results show that upward and downward fluxes develop in the upper part of the fault zone, controlled by the action of the alluvial aquifer, influencing the recharge of the sedimentary basin. This paper shows the hydrological efficiency of fault zones as preferential flow; it also analyses the constraints that determine groundwater recharge to the surrounding basins. These results contribute to the understanding of hydrogeological dynamics in tectonic areas. Copyright © 2008 John Wiley & Sons, Ltd.
Sediment trapping by a tree belt: processes and consequences for sediment delivery
Authors: Leguédois Sophie , Ellis Tim W. , Hairsine Peter B. , Tongway David J. 
Published: January 2008

AbstractRestoring belts of perennial vegetation in landscapes is widely recognized as a measure of improving landscape function. While there have been many studies of the transport of pollutants through grass filter strips, few have addressed sediment related processes through restored tree belts. In order to identify these processes and quantify their relative contribution to sediment trapping, a series of rainfall simulations was conducted on a 600 m2 hillslope comprising a pasture upslope of a 15 year old tree belt. Although the simulated events were extreme (average recurrence intervals ∼10 and 50 yr), the trapping efficiency of the tree belt was very high: at least 94% of the total mass of sediments was captured. All the size fractions were trapped with a minimum Sediment Trapping Ratio (STR) of 91% for the medium‐sized fragments. Fractions < 1·3 µm and > 182 µm were totally captured (STR = 100%). Through the joint analysis of sediment budgets and soil surface conditions, we identified different trapping processes. The main trapping process is the sedimentation (at least 62% of trapped sediment mass) with deposits in the backwater and as micro‐terraces within the tree belt. Modelling results show that the coarsest size fractions above 75 µm are preferentially deposited. Joint infiltration of water and sediments has also been noticed, however, this process alone cannot explain the selective trapping of the finest fractions. We suggest that the finest fractions transported by the overland flow may be trapped by adsorption on the abundant litter present within the tree belt. Copyright © 2008 John Wiley & Sons, Ltd.
Children's, adolescents', and adults' reference to goals to explain interpersonal actions
Authors: Pillow Bradford H. , Lovett Suzanne B. , Hill Valerie 
Published: January 2008

AbstractThis study investigated children's, adolescents', and adults' references to an actor's goals when explaining interpersonal actions. Participants were presented with eight brief stories containing a variety of social events and were asked to explain why the actor in each story performed the central action. Children, adolescents, and adults mentioned goals for most of the stories. Adults and adolescents mentioned psychological goals much more often than did children. Older children, adolescents, and adults mentioned complex psychological goals more often than did younger children. Younger children often mentioned instrumental or social goals. When making goal attributions, children, adolescents, and adults considered both the nature of the action and the social context in which it occurred. Participants mentioned psychological goals more often when explaining an antisocial action and social goals when explaining a prosocial action. Participants were also more likely to mention psychological goals when interpersonal events immediately preceding the central action were described. Thus, goals were offered as explanations for interpersonal actions by all age groups, but the type of goals mentioned varied by the age of the participant, the social context, and the valence of the action. Copyright © 2008 John Wiley & Sons, Ltd.
Proteome response in HT‐29 human colorectal cancer cells to two apoptosis‐inducing compounds with different mode of action
Authors: Winkelmann Isabel , Näßl Anna‐Maria , Daniel Hannelore , Wenzel Uwe 
Published: January 2008

AbstractFlavone and camptothecin were both shown to potently induce apoptosis in HT‐29 human colon cancer cells. Whereas camptothecin acts on the basis of topoisomerase‐I inhibition, flavone appears to burst mitochondrial production of reactive oxygen species by increasing respiratory chain activity. In our study, we searched for similarities and differences in the proteome response of HT‐29 cells when treated with the two different compounds. The accessible proteome of HT‐29 cells was separated subsequent to the exposure to flavone or camptothecin by 2D‐polyacrylamide‐gel electrophoresis using pH‐gradients between 4 and 7 and 6 and 11 in the first dimension and proteins with changed expression level were identified by peptide mass fingerprints of tryptic digests of the protein spots. Whereas there was a high congruence with regard to the identities of regulated proteins and their grade of regulation, a number of spots changed specifically only in response to either flavone or camptothecin. Nuclear envelope proteins were specifically increased by camptothecin indicating the intervention of this drug with cell division processes. Increased levels of coproporphyrinogen III oxidase, involved in cytochrome synthesis, and ubiquinol‐cytochrome‐c reductase suggest adaptations to flavone in order to enable a higher substrate flux through the respiratory chain. In conclusion, HT‐29 cells respond to camptothecin and flavone with regulations of many proteins in a similar manner suggesting those alterations to be caused by apoptosis induction. Some protein regulations, however, were specific for each compound and point to the mechanism of their action. © 2008 Wiley‐Liss, Inc.
Nisin expression production from Lactococcus lactis in milk whey medium
Authors: de Arauz Luciana Juncioni , Jozala Angela Faustino , Pinheiro Gabriel Soares , Mazzola Priscila Gava , Júnior Adalberto Pessoa , Vessoni Penna Thereza Christina 
Published: January 2008

AbstractBACKGROUND: Nisin is a commercially available bacteriocin produced by Lactococcus lactis ATCC 11454 and used as a natural agent in the biopreservation of food. In the current investigation, milk whey, a byproduct from dairy industries was used as a fermentation substrate for the production of nisin. Lactococcus lactis ATCC 11454 was developed in a rotary shaker (30 °C/36 h/100 rpm) using two different media with milk whey (i) without filtration, pH 6.8, adjusted with NaOH 2 mol L−1 and without pH adjustment, both autoclaved at 121 °C for 30 min, and (ii) filtrated (1.20 µm and 0.22 µm membrane filter). These cultures were transferred five times using 5 mL aliquots of broth culture for every new volume of the respective media.RESULTS: The results showed that culture media composed of milk whey without filtration supplied L. lactis its adaptation needs better than filtrated milk whey. Nisin titers, in milk whey without filtration (pH adjusted), was 11120.13 mg L−1 in the second transfer, and up to 1628‐fold higher than the filtrated milk whey, 6.83 mg.L−1 obtained in the firstt transfer.CONCLUSIONS: Biological processing of milk byproducts (milk whey) can be considered a profitable alternative, generating high‐value bioproducts and contributing to decreasing river disposals by dairy industries. Copyright © 2008 Society of Chemical Industry
Operational strategy for a partial nitritation–sequencing batch reactor treating urban landfill leachate to achieve a stable influent for an anammox reactor
Authors: Ganigué Ramon , López Helio , Ruscalleda Maël , Balaguer M. Dolors , Colprim Jesús 
Published: January 2008

AbstractBACKGROUND: In recent years, new technologies have been developed to deal with streams with high nitrogen loads, most of them based on the anammox process. As a first step in this process, ammonium has to be partially oxidized to nitrite. This partial nitritation is usually carried out through the SHARON process. However, it can also be achieved using other configurations (sequencing batch reactor or biofilm airlift, among others). The aim of this paper is to compare two different feeding strategies (fed‐batch and step‐feed) for the operation of a partial nitritation–sequencing batch reactor (PN‐SBR) treating raw urban landfill leachate.RESULTS: A PN‐SBR treating urban landfill leachate was started up and operated using two different feeding strategies: fed‐batch and step‐feed. When the experimental results were compared, it could be seen that during the step‐feed strategy the system was more stable and presented a better performance. In addition, a cycle profile evolution of the reactor in each strategy was carried out to study the dynamics of the main chemical compounds, as well as different physical parameters. The profiles were similar for the nitrogen compounds, but with a difference in behaviour of pH, inorganic carbon and oxygen uptake ratio, which could explain the better performance and stability of the step‐feed strategy.CONCLUSIONS: This study has demonstrated that the step‐feed strategy is more suitable than the fed‐batch because it performs better overall, there is less fluctuation in its operation and it has higher effluent quality stabilization. Copyright © 2008 Society of Chemical Industry
A novel approach to precipitation series completion in climatological datasets: application to Andalusia
Authors: Ramos‐Calzado P. , Gómez‐Camacho J. , Pérez‐Bernal F. , Pita‐López M. F. 
Published: January 2008

AbstractComplete monthly series of precipitation data have been generated for 932 stations run by the Instituto Nacional de Meteorología (INM) in Andalusia (Andalucía, southern region of Spain) and some adjacent areas for the period 1961–2000 using a new method for the estimation of missing data. The proposed method fills in the gaps in the climatological series for a target station using precipitation data from neighbouring stations with a similar precipitation pattern. Particular emphasis is made in the consideration of the precipitation data uncertainty. A set of possible estimates for the missing data are obtained assuming a linear relationship between the target station and the selected neighbour stations. The final imputed value is the median of the previously evaluated estimates distribution. This approach also provides the uncertainty of the missing data estimate. As an application, the suggested approach is used to obtain a precipitation map of Andalusia, as well as the average annual series for the examined period. Copyright © 2008 Royal Meteorological Society