bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of fines migration using a non‐Newtonian lattice Boltzmann‐discrete element model
Authors: Leonardi C.R. , Owen D.R.J. , Feng Y.T. 
Published: April 2013

PurposeThe purpose of this paper is to present a novel computational framework capable of simulating the block cave phenomenon of fines migration in two dimensions. Fines migration is characterised by the faster movement of fine and often low‐grade material towards the draw point in comparison to larger, blocky material. A greater understanding of the kinematic behaviour of fines and ore within the cave during draw is integral to the solution of this problem.Design/methodology/approachThe lattice Boltzmann method (LBM) is employed in a nonlinear form to represent the fines as a continuum, and it is coupled to the discrete element method (DEM) which is used to represent large blocks. The issues relevant to this approach, such as fluid‐solid interaction, the synchronisation of explicit schemes, and the characterisation of a bulk material as a non‐Newtonian fluid are discussed.FindingsResults of the 2D simulations reveal migration trends for the geometries, material properties and operational sequences analysed. By executing an extensive programme of numerical experiments the influence of these and other relevant block cave factors on the migration of fines could be isolated.Originality/valueTo the authors' knowledge, this is the first time the LBM has been used to simulate the flow of bulk materials. The non‐Newtonian LBM‐DEM framework is also a novel approach to the investigation of fines migration, which until now has been limited to scale models, cellular automata or pure DEM simulations. The results of the 2D migration analyses highlight the potential for this novel approach to be applied in an industrial context and also encourage the extension of the framework to 3D.
Iterative algorithms for the generalized centro‐symmetric and central anti‐symmetric solutions of general coupled matrix equations
Authors: Dehghan Mehdi , Hajarian Masoud 
Published: April 2013

PurposeThe purpose of this paper is to find two iterative methods to solve the general coupled matrix equations over the generalized centro‐symmetric and central antisymmetric matrices.Design/methodology/approachBy extending the idea of conjugate gradient (CG) method, the authors present two iterative methods to solve the general coupled matrix equations over the generalized centro‐symmetric and central antisymmetric matrices.FindingsWhen the general coupled matrix equations are consistent over the generalized centro‐symmetric and central anti‐symmetric matrices, the generalized centro‐symmetric and central anti‐symmetric solutions can be obtained within nite iterative steps. Also the least Frobenius norm generalized centrosymmetric and central anti‐symmetric solutions can be derived by choosing a special kind of initial matrices. Furthermore, the optimal approximation generalized centrosymmetric and central anti‐symmetric solutions to given generalized centro‐symmetric and central anti‐symmetric matrices can be obtained by finding the least Frobenius norm generalized centro‐symmetric and central anti‐symmetric solutions of new matrix equations. The authors employ some numerical examples to support the theoretical results of this paper. Finally, the application of the presented methods is highlighted for solving the projected generalized continuous‐time algebraic Lyapunov equations (GCALE).Originality/valueBy the algorithms, the solvability of the general coupled matrix equations over generalized centro‐symmetric and central anti‐symmetric matrices can be determined automatically. The convergence results of the iterative algorithms are also proposed. Several examples and an application are given to show the efficiency of the presented methods.
Analytical method for solving steady MHD convective and slip flow due to a rotating disk with viscous dissipation and Ohmic heating
Authors: Rashidi M.M. , Erfani E. 
Published: April 2013

PurposeThe purpose of this paper is to consider the thermal‐diffusion and diffusion‐thermo effects on combined heat and mass transfer of a steady magnetohydrodynamic (MHD) convective and slip flow due to a rotating disk with viscous dissipation and Ohmic heating. The main goal of the present study is to find the approximate analytic solutions by the combination of the DTM and the Padé approximants for this problem.Design/methodology/approachA new method, namely the DTM‐Padé technique, which is a combination of the differential transform method and the Padé approximation, is employed.FindingsGraphical results for fluids of medium molecular weight (H2, air) are presented to investigate influence of the slip parameter, magnetic field parameter M, Eckert Ec, Schmidt Ec, Dufour Du and Soret Sr numbers on the profiles of the dimensionless velocity, temperature and concentration distributions. In order to show the effectiveness of the DTM‐Padé, the results obtained from the DTM‐Padé are compared with available solutions obtained using shooting method to generate the numerical solution.Originality/valueThis technique (DTM‐Padé) is extended to give solutions for nonlinear differential equations with boundary conditions at the infinity.
Real and virtual segments of modern library space
Authors: Zverevich Victor 
Published: April 2013

PurposeThe purpose of this paper is to review the considerations necessary in developing modern library spaces.Design/methodology/approachBoth internal and external segments of library space are analyzed from the positions of their physical availability to users, services offered and future prospects.FindingsThe findings indicate that the library space consists of two segments: internal and external. Internal space is physical space with traditional documents and services, and the external segment is physically intangible virtual space dealing with virtual services using electronic resources.Originality/valueThe two segments of library space have not previously been considered together in one paper. Also, virtual library resources and services, in respect of relating them to the certain segment of library space, have not been considered previously.
Libraries as the gate: “ways” and “keepers” in the knowledge environment
Authors: Oyelude Adetoun A. , Bamigbola Alice A. 
Published: April 2013

PurposeThis paper examines whether the library is a gateway to knowledge, or a gatekeeper in the digital knowledge environment.Design/methodology/approachAn online opinion survey was carried out using the LinkedIn social media.FindingsHalf (50 per cent) of the respondents regarded the library as both gateway and gatekeeper; 47 per cent as gateway; and 1 per cent as gatekeeper. Challenges to the library functioning in either of the roles were those of technology use in serving their clientele.Research limitations/implicationsThe implication for librarians and libraries in the perceived blend of the two roles of gateway and gatekeeper is significant. Future research could find out the effect of the new open access movement on gateway/gatekeeper roles in libraries.Practical implicationsLibraries as gateways should cater for problems of access, accessibility, copyright violations, institutional repository issues, security issues (physical and electronic) and others. As gatekeepers there is the need to collaborate in resources sharing, training opportunities and content.Social implicationsWith libraries as gateways and gatekeepers, society will be able to have improved library services and assured of access with the new digital publishing dynamics in a balanced environment.Originality/valueThe paper is valuable to libraries and librarians as it helps them to redefine their functions with the changes ongoing in the knowledge environment.
A study of institutional repositories on women's studies in India and Canada
Authors: Sawant Sarika 
Published: April 2013

PurposeThe purpose of this paper is to examine institutional repositories developed in India and Canada containing documents on women's studies.Design/methodology/approachThe methodology consisted of identification of institutional repositories containing documents on women's studies, development of a tool for evaluation, followed by actual evaluation/content analysis of identified repositories.FindingsIt was found that there were 22 institutional repositories in Canada and three in India containing documents on women's studies. The highest number of documents on women's studies were available in the IR of University of British Columbia, i.e. 9,778. About 56 per cent (14) of the repositories contained community on the women's studies.Research limitations/implicationsThose institutional repositories containing documents on women's studies developed in India and Canada were considered for the study.Originality/valueThis is one of the first studies focused on issues on women's studies and repositories.
Prospects and barriers for Russia's emerging ESCO market
Authors: Garbuzova‐Schlifter Maria , Madlener Reinhard 
Published: April 2013

PurposeThe Russian Energy Service Company (ESCO) market emerges rapidly due to the new energy efficiency legislation that has been implemented since 2009. However, a clear identification of the Russian ESCOs, comparable to those operating on the basis of Energy Performance Contracting (EPC) in the Western markets, remains rather difficult. Hence, aside from the independent ESCOs identified, further energy service‐providing companies (ESPCs) are within the scope of this survey. This paper aims to address these issues.Design/methodology/approachBuilding on comprehensive qualitative research of the international and Russian academic and non‐academic literature on the ESCO concept and an expert interview, an explorative, questionnaire‐based survey among 161 Russian energy companies and organizations was conducted. A total of 28 usable responses were returned, corresponding to a response rate of 17 per cent. Non‐parametric exact tests are used for the statistical analysis.FindingsThe authors' findings show that only nine of the surveyed ESCOs have acquired energy performance‐based projects. In line with the new energy efficiency legislation, such projects are strongly supported in the state sector but much less so in the commercial sector. Most of the projects are financed either through ESCOs' own funds, direct loans to customers, or by the customers themselves. Russian banks, however, rarely provide direct loans for energy performance‐based projects of ESCOs, but rather prefer to offer financial leasing contracts. The contractual form “guaranteed savings”, which is generally more applicable in mature ESCO markets, is gaining in importance, while “shared savings” is barely used.Originality/valueThis paper delivers, to the best of the authors' knowledge, the first systematic empirical investigation of the Russian ESCO industry, taking into account experiences from the international ESCO markets.
Climate warming and ectotherm body size – from individual physiology to community ecology
Authors: Ohlberger Jan 
Published: April 2013

SummaryAccumulating evidence suggests that the average body size of many organisms is declining in response to climate warming. This phenomenon has been suggested to represent a universal response to warming that may impose significant adverse effects on ecosystem functioning and services.However, we do not have a thorough understanding of why body sizes are commonly declining, and why some organisms show the opposite response. Because ectotherms constitute the vast majority of organism biomass and about 99% of species worldwide, it is particularly important to understand how ectotherms respond to a warming climate.This review discusses the underlying physiological mechanisms of changes in ectotherm body size and addresses observed responses within a broad ecological context at different levels of organization, from individuals to communities, particularly in aquatic systems.Warming‐induced responses in average body size are not only determined by changes in rates of individual growth and development, but also mediated through size‐dependent feedbacks at the population level, as well as competitive and predatory interactions within the community. Emergent properties at higher organizational levels have already been observed in both experimental and natural systems.Various approaches will be required for enhancing our knowledge about the importance of such processes in natural systems. These include controlled semi‐natural experiments and phylogenetic comparisons as well as statistical models of time‐series data and theoretical models linking climate effects at the individual, population and community levels.Understanding causes of observed changes in organism body sizes and how these depend on the ecological context is essential for improving our predictions and the management of ecosystems in the face of a warming climate.
Controlled laboratory experiments to assess the geomechanical influence of subsurface injection and depletion processes on 4D seismic responses
Authors: Holt Rune M. , Stenebråten Jørn F. 
Published: April 2013

ABSTRACTLaboratory experiments are performed with soft synthetic reservoir sandstone cemented under stress and with synthetic overburden (caprock) material consisting of compacted clay (kaolinite) in brine. The rock‐like materials are loaded mechanically under stress paths representative of stress changes occurring in the subsurface as a result of injection (increasing pore pressure) or depletion followed by injection into a storage reservoir. Static stress‐strain behaviour and multidirectional P‐ and S‐wave velocities are monitored during the tests. The tests with sandstone are performed on dry material and simple poroelastic modelling is performed to relate these data to the behaviour of fluid (water / CO2) saturated samples under the same stress paths. The focus is on identifying 4D seismic attributes that may be used in the field to interpret monitoring measurements. This could help diagnose stress changes in the overburden, signalling the risk of CO2 leakage from a reservoir if the compressive or tensile strength limit of the overburden is reached and of course to help quantify amounts of CO2 stored.
Accrual to Trans‐Tasman Radiation Oncology Group‐sponsored trials 2010–2012
Authors: Christie David RH 
Published: April 2013

AbstractIntroductionFew trials groups report analyses of accrual. Although Trans‐Tasman Radiation Oncology Group (TROG) has reported accrual within individual trials, no analysis has ever been reported. Type A trials are those trials for which TROG is the principal sponsor and are dependent on accrual from TROG centres. The aim of this study was to review accrual rates to type A trials over the last 3 years.MethodsAll type A trials that had presented accrual data during the TROG annual scientific meetings and the trials review meetings between April 2010 and April 2012 were reviewed. Expected accrual rate (EAR) and actual accrual rate (AAR) were estimated from accrual curves as well as initial delays in accrual. Ratios of AAR to EAR (RAEAR) were calculated.ResultsThere were 16 type A trials from which estimates could be made. The median EAR was 40 patients per year and the median AAR was 20 patients per year. Wide variations in each were noted and the median RAEAR was 0.67. The median initial delay was 7.5 months.ConclusionsAlthough TROG is a highly successful trials organisation, the median AAR is only half of the median EAR and in only three trials (19%) was the AAR the same or more than the EAR. Future reports could address potential factors affecting the AAR but would require prospective data collection. The RAEAR is one of many factors that can be used to help determine which trials should continue. Overall rates of accrual can be used as a record of TROG's productivity.
Once‐daily reirradiation for rectal cancer in patients who have received previous pelvic radiotherapy
Authors: Ng Michael K Y , Leong Trevor , Heriot Alexander G , Ngan Samuel Y K 
Published: April 2013

AbstractIntroductionThe purpose of this study is to assess the efficacy and toxicity using once‐daily reirradiation for patients with rectal cancer having received previous pelvic radiotherapy.MethodBetween June 1997 and June 2008, 56 patients were identified having received previous pelvic radiotherapy and received reirradiation for rectal cancer. Reirradiation intent was palliative in 43 patients, and preoperative/postoperative in 13 patients. Eighty per cent of patients received concurrent chemotherapy (n = 45).ResultsThe median dose‐fractionation reirradiation schedule was 39.6 Gy in 22 fractions once daily (range 20–39.6 Gy), and the median cumulative radiation dose was 87.3 Gy. Seven patients experienced a grade 3 acute toxicity, with no grade 4 event. Fifty‐one patients (91%) completed the treatment and five patients required a treatment break. The overall symptomatic response rate was 88% at three months post‐reirradiation. There was one late effect of skin ulceration among patients reirradiated palliatively. Median overall survival was 39 months in patients undergoing radical surgery versus 15 months in patients reirradiated palliatively (P < 0.001).ConclusionOnce‐daily reirradiation to a total dose of ≤39.6 Gy is relatively safe in the treatment of patients with rectal cancer after previous pelvic radiotherapy. It is effective in symptom control and provides an additional option in management of local recurrence.
Apparent survival estimation from continuous mark–recapture/resighting data
Authors: Barbour Andrew B. , Ponciano José M. , Lorenzen Kai 
Published: April 2013

Summary

The recent expansion of continuous‐resighting telemetry methods (e.g. acoustic receivers, PIT tag antennae) has created a class of ecological data not well suited for traditional mark–recapture statistics. Estimating survival when continuous recapture data is available ensues a practical problem, because classical capture–recapture models were derived under a discrete sampling scheme that assumes sampling events are instantaneous with respect to the interval between events.

To investigate the use of continuous data in survival analysis, we conducted a model structure adequacy simulation that tested the Cormack–Jolly–Seber (CJS) and Barker joint data survival estimation models, which mainly differ through the Barker's inclusion of secondary period information. We simulated a population in which survival and detection occurred as a near continuous (daily) process and collapsed detection information into monthly sampling bins for survival estimation.

While both models performed well when survival was time‐independent, the CJS was substantially biased for low survival values and time‐dependent conditions. Additionally, unlike the CJS, the Barker model consistently performed well over multiple sample sizes (number of marked individuals). However, the high number of parameters in the Barker model led to convergence difficulties, resulting in a need for an alternative optimization method (simulated annealing).

We recommend the use of the Barker model when using continuous data for survival analysis, because it outperformed the CJS over a biologically reasonable range of potential parameter values. However, the practical difficulty of implementing the Barker model combined with its shortcomings during two simulations leaves room for the specification of novel statistical methods tailored specifically for continuous mark–resighting data.
Epidural vs. intravenous fentanyl during colorectal surgery using a double‐blind, double‐dummy design
Authors: SADURNÍ M. , BELTRÁN DE HEREDIA S. , DÜRSTELER C. , PÉREZ‐RAMOS A. , LANGOHR K. , ESCOLANO F. , PUIG M. M. 
Published: April 2013

BackgroundThe overall therapeutic effectiveness of epidural fentanyl vs. the intravenous route is controversial. The present work describes a randomized, controlled, double‐blind, double‐dummy study of the intraoperative requirements of fentanyl administered by the intravenous or epidural routes during open colon surgery.MethodsThirty patients were randomized to receive intraoperative analgesia with boluses of fentanyl administered by either the epidural or intravenous route (2 μg/kg). The first fentanyl bolus was administered 10 min before incision, and repeated boluses were given when mean arterial pressure or heart rate increased more than 20% over basal values. General anaesthesia was maintained with a propofol infusion. Intraoperative fentanyl and propofol requirements, time to awakening, time to analgesia request, and incidence of adverse effects were recorded.ResultsMedian [interquartile range (range)] fentanyl requirements in the epidural and intravenous groups were 0.81 [0.65 (0.47–2.61)] and 2.5 [1.08 (1.07–4.85)] μg/kg/h, respectively (P < 0.001). The epidural group had a shorter time to awakening, with a median of 8 min [4.5 (3–18)] compared with 20 min [12.5 (7–34)] for the intravenous group (P < 0.001). There were no significant differences in propofol requirements. The time to analgesia request was also delayed in the epidural group, with a median of 5 h [5.5 (1–16)] vs. 2 h [1 (1–5)] when fentanyl was administered intravenously (P < 0.001). The incidence of adverse effects was similar in both groups.ConclusionDuring major abdominal surgery, epidural administration requires lower doses of intraoperative fentanyl when compared with the intravenous route. Epidural fentanyl also facilitates early awakening and residual analgesia without increasing adverse events.
Effects of an invasive species on refuge‐site selection by native fauna: The impact of cane toads on native frogs in the Australian tropics
Authors: Bleach Iris , Beckmann Christa , Brown Gregory P. , Shine Richard 
Published: April 2013

AbstractInvasive species can induce shifts in habitat use by native taxa: either by modifying habitat availability, or by repelling or attracting native species to the vicinity of the invader. The ongoing invasion of cane toads (Rhinella marina) through tropical Australia might affect native frogs by affecting refuge‐site availability, because both frogs and toads frequently shelter by day in burrows. Our laboratory and field studies in the wet‐dry tropics show that native frogs of at least three species (Litoria tornieri, Litoria nasuta and Litoria dahlii) preferentially aggregate with conspecifics, and with (some) other species of native frogs. However, the frogs rarely aggregated with cane toads either in outdoor arenas or in standardized experimental burrows that we monitored in the field. The native frogs that we tested either avoided burrows containing cane toads (or cane toad scent) or else ignored the stimulus (i.e. treated such a burrow in the same way as they did an empty burrow). Native frogs selected a highly non‐random suite of burrows as diurnal retreat sites, whereas cane toads were less selective. Hence, even in the absence of toads, frogs do not use many of the burrows that are suitable for toads. The invasion of cane toads through tropical Australia is unlikely to have had a major impact on retreat‐site availability for native frogs.