bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing the applicability of groundwater monitoring data in the modelling of soil water retention characteristics
Authors: Orzepowski Wojciech , Paruch Adam M. , Kowalczyk Tomasz , Pokładek Ryszard , Pulikowski Krzysztof 
Published: August 2018

AbstractThe present work focuses on an assessment of the applicability of groundwater table (GWT) measures in the modelling of soil water retention characteristics (SWRC) using artificial neural network (ANN) methods. Model development, testing, validation and verification were performed using data collected across two decades from soil profiles at full‐scale research objects located in Southwest Poland. A positive effect was observed between the initial GWT position data and the accuracy of soil water reserve estimation. On the other hand, no significant effects were observed following the implementation of GWT fluctuation data over the entire growing season. The ANN tests that used data of either soil water content or GWT position gave analogous results. This revealed that the easily obtained data (temperature, precipitation and GWT position) are the most accurate modelling parameters. These outcomes can be used to simplify modelling input data/parameters/variables in the practical implementation of the proposed SWRC modelling variants.
MODELING THE COSMOS: TRANSFORMATIVE PEDAGOGY IN SCIENCE AND RELIGION
Authors: Hickman Louise 
Published: August 2018

AbstractThis article reflects on the classroom pedagogy promoted by Christopher Southgate and its implications for the science–theology conversation. It highlights several important aspects of Southgate's pedagogy. The use of models of God, humanity, and cosmos emphasize relationality while encouraging the synthesizing of ideas. The promotion of holism in theological reflection is vital for nurturing students to become theologians themselves through the active reevaluation of key doctrines and ideas. An emphasis on ethical considerations reinforces synthesis between theology, science, and ethics, and is vital for perspective transformation. These aspects of Southgate's teaching should be recognized as vital for promoting intellectual independence, partnership, and theological transformation, all of which are essential to good science and theology pedagogy.
DARWIN AND CHRISTIANITY: TRUTH AND MYTH
Authors: Brooke John Hedley 
Published: August 2018

AbstractIn recent years many historical myths about the relations between science and religion have been corrected but not always with sensitivity to different types and functions of “myth.” Correcting caricatures of Darwin's religious views and of the religious reaction to his theory have featured prominently in this myth‐busting. With the appearance in 2017 of A. N. Wilson's depiction of Darwin himself as a “mythmaker,” it is appropriate to reconsider where the myths lie in discourse concerning Darwin and Christianity. Problems with Wilson's account are identified and his provocative demeaning of Darwin is contrasted with an image gleaned from Darwin's friend and colleague George Romanes. The article concludes with a brief reference to the problem of suffering and to the work of Christopher Southgate.
CHRISTOPHER SOUTHGATE'S COMPOUND THEODICY: PARALLEL SEARCHINGS
Authors: Edwards Denis 
Published: August 2018

AbstractChristopher Southgate proposes that a theological response to the suffering that is built into an evolutionary world requires a compound evolutionary theodicy, made up of four interrelated theological positions. This article proposes a fourfold response to the suffering of nonhuman creation that parallels Southgate's compound theodicy. In its similarities and differences, it is offered in the spirit of a tribute to Christopher Southgate.
BETWEEN KNOWING AND BEING: REFLECTIONS ON BEING TAUGHT SCIENCE AND RELIGION BY PROFESSOR CHRISTOPHER SOUTHGATE
Authors: Gibson Timothy 
Published: August 2018

AbstractIt is a joy to be asked to contribute to this commemorative edition of Zygon, in honor of my friend Christopher Southgate. But a narrowly academic article seems not to fit the brief of writing a reflection on Southgate's teaching of science and religion, as one who has witnessed it, gladly, as both student and colleague. What follows, then, is deliberately reflective in tone, with little in the way of academic references apart from occasional links to Southgate's own work—though, I hope, enough of a strand of argument to justify inclusion in these pages. My argument is simply put: Southgate teaches by not teaching, but by drawing out knowledge from students and thereby empowering their growth. He is an exemplar, a kind man committed to the unfolding of understanding, interested too in forming dispositions in his students that will lead to their flourishing as thinkers and as people.
SOUTHGATE'S COMPOUND ONLY‐WAY EVOLUTIONARY THEODICY: DEEP APPRECIATION AND FURTHER DIRECTIONS
Authors: Russell Robert John 
Published: August 2018

AbstractChristopher Southgate offers a remarkable evolutionary theodicy that includes six affirmations and arguments; together they form a unique and very persuasive proposal which he terms a “compound evolutionary theodicy.” Here I summarize the arguments and offer critical reflections on them for further development, with an emphasis on the ambiguity in the goodness of creation; the role of thermodynamics in evolutionary biology; the challenge of horrendous evil in nature; and the theological response to theodicy in terms of eschatology, with its own severe challenge from cosmology.
EXTINCTION, NATURAL EVIL, AND THE COSMIC CROSS
Authors: Peters Ted 
Published: August 2018

AbstractDid the God of the Bible create a Darwinian world in which violence and suffering (disvalue) are the means by which the good (value) is realized? This is Christopher Southgate's insightful and dramatic formulation of the theodicy problem. In addressing this problem, the Exeter theologian rightly invokes the Theology of the Cross in its second manifestation, that is, we learn from the cross of Jesus Christ that God is present to nonhuman as well as human victims of predation and extinction. God co‐suffers with creatures in their despair, abandonment, physical suffering, and death. What I will add with more force than Southgate is this: the Easter resurrection is a prolepsis of the eschatological new creation, and it is God's new creation which retroactively determines past creation. Although this does not eliminate the theodicy question, it lessens its moral sting.
CREATIVE MUTUAL INTERACTION IN ACTION
Authors: Robinson Andrew 
Published: August 2018

AbstractIn this article, I describe a multidisciplinary project at the interface of philosophy, science, and theology. The project is the product of an ongoing collaboration between the author and Christopher Southgate, to whom this special issue of Zygon is dedicated. At the philosophical core of the project is a development of C. S. Peirce's semiotics (theory of signs). The scientific branch of the project involves the application of semiotic theory to the problem of the origin of life, and to questions about human evolution and human distinctiveness. The theological branch of the project involves the articulation of a semiotic approach to the Christian concepts of Incarnation and Trinity, and to the ideas of vestiges of the Trinity in creation and of participation in God's life. The purpose of this paper is to analyze the project in terms of Robert John Russell's model of ‘creative mutual interaction’ between science and theology.
THEODICY: A RESPONSE TO CHRISTOPHER SOUTHGATE
Authors: Hoggard Creegan Nicola 
Published: August 2018

AbstractThis article is a critical and appreciative interaction with Christopher Southgate's theodicy and theology of glory. I critique in particular his rejection of all dualist moves in theodicy. I question why Southgate can ascribe evil to some human actions, many of which are automatic and unconscious, but not to any other level or form of consciousness. I argue that he may rely too heavily on rational scientific categories, which are not sufficient in themselves to carry the weight of key theological concepts. His use of poetry is powerful and suggestive, but in the end, he may not give it enough epistemic weight.
Capability of the Bayesian Forecasting Method to Predict Field Time Series
Authors: Gatta Nicolò , Venturini Mauro , Manservigi Lucrezia , Ceschini Giuseppe Fabio , Bechini Giovanni 
Published: August 2018

This paper addresses the challenge of forecasting the future values of gas turbine measureable quantities. The final aim is the simulation of “virtual sensors” capable of producing statistically coherent measurements aimed at replacing anomalous observations discarded from the time series.
Among the different available approaches, the Bayesian Forecasting Method (BFM) adopted in this paper uses the information held by a pool of observations as knowledge base to forecast the values at a future state.
The BFM algorithm is applied in this paper to Siemens field data to assess its prediction capability, by considering two different approaches, i.e. single-step prediction (SSP) and multi-step prediction (MSP). While SSP predicts the next observation by using true data as base of knowledge, MSP uses previously predicted data as base of knowledge to perform the prediction of future time steps.
The results show that BFM single-step average prediction error can be very low, when filtered field data are analyzed. On the contrary, the average prediction error achieved in case of BFM multi-step prediction is remarkably higher. To overcome this issue, the BFM single-step prediction scheme is also applied to clusters of time-wise averaged data. In this manner, an acceptable average prediction error can be achieved by considering clusters composed of 60 observations.
Exergy Loss Considerations in Education for a Turbofan Power Cycle
Authors: Wettstein Hans E. 
Published: August 2018

The conversion of heat into mechanical shaft power or electrical energy is still the worldwide most used electric and propulsion energy source. Whether coal, liquid hydrocarbons, natural gas, nuclear or solar heat are used as primary energy source such cycles are continuously improved aiming at better efficiency, at flexible operating conditions or at reducing manufacturing or maintenance cost.
The classic thermal power cycle design uses detailed simulation of the cycle fluid’s changes of state (typically represented by averaged pressure and temperature or specific enthalpy) along the flow paths. Components of such a cycle may be ducts, filters, mixers, compressors, combustors, heat exchangers, nozzles, turbine stages etc.
The notations of exergy and anergy were invented in the nineteen-fifties but they still play an astonishingly silent role in education. Knowing already the Carnot factor a student can understand the second law of thermodynamics by the simple fact that the exergy part of energy can be converted into any other form of energy while the anergy part cannot be converted into any exergy form of energy. The most used approach via the saying “that the state variable entropy can only grow” is for most students a mental detour because they do not understand the tie of energy conversion and entropy.
The exergy loss breakdown of a cycle gives an instructive view to opportunities and challenges. This paper explains methods to calculate a breakdown of the exergy losses with the example of a typical but notional turbofan using commercially confirmed component performance data.
The considerations cover exergy losses by heat exchange, by combustion, by heat loss to ambient, by mixing different fluids, by internal pressure losses, by friction and dissipation in turbomachinery and by the bottoming heat discharge as well as in the propulsive process. Quantified exergy losses for such effects make the limitations of technical improvements visible without going into detailed design work.
The purpose of this paper is to motivate for teaching and using exergy-based considerations especially in the basic performance simulation. Additionally the context is occasion for an extra plea on replacing the colloquial expression “energy consumption” by “exergy consumption”. The reader of this paper should have basic knowledge of thermodynamic cycle performance simulation methods and of turbomachinery.
Rotordynamic Characterization of a Staggered Labyrinth Seal: Experimental Test Data and Comparison With Predictions
Authors: Cangioli Filippo , Vannini Giuseppe , Pennacchi Paolo , Ciuchicchi Lorenzo , Nettis Leonardo , Chatterton Steven 
Published: August 2018

As well known, the stability assessment of turbomachines is strongly related to internal sealing components. For instance, labyrinth seals are widely used in compressors, steam and gas turbines and pumps to control the clearance leakage between rotating and stationary parts, owing to their simplicity, reliability and tolerance to large thermal and pressure variations. Labyrinth seals working principle consists in reducing the leakage by imposing tortuous passages to the fluid that are effective on dissipating the kinetic energy of the fluid from high-pressure regions to low-pressure regions. Conversely, labyrinth seals could lead to dynamics issues. Therefore, an accurate estimation of their dynamic behavior is very important.
In this paper, the experimental results of a long-staggered labyrinth seal will be presented. The results in terms of rotordynamic coefficients and leakage will be discussed as well as the critical assessment of the experimental measurements.
Eventually, the experimental data are compared to numerical results obtained with the new bulk-flow model (BFM) introduced in this paper.
Numerical Simulations of CO2 Compressors at Near-Critical and Sub-Critical Inlet Conditions
Authors: Hosangadi A. , Weathers T. , Liu Z. , Ahuja V. , Busby J. 
Published: August 2018

An advanced real-fluid numerical framework for transcritical CO2 spanning both the supercritical and sub-critical regime near the critical point is presented. The numerical algorithm is specifically designed to faithfully model sharp variations of thermodynamic derivatives near the critical point. Numerical results for compressor performance in the Sandia test loop [1] at near critical inlet conditions have been presented over a range of flow rates from the choke point to the stall line. The analysis identifies the shift in the flow losses from the impeller to the diffuser as the flow rate increases from the stall to choke limit. The simulations have been compared with both the Sandia performance curves as well as raw data from Barber Nichols Inc. (BNI); the results compare well with the raw data and provide good qualitative comparisons with Sandia’s performance curves [1].
The numerical framework has also been extended to sub-critical conditions by solving for separate transport equations for each phase. Methodology for NIST table lookup at sub-critical conditions to identify liquid and vapor properties has been developed. Phase change is triggered when local conditions go sub-critical and do not require the phase to be specified a priori. Calculations at both near critical inlet temperatures as well as a two-phase inlet condition at lower temperatures were modeled. Significant difference in the phase change characteristics at these two conditions have been identified and discussed in the paper.
Off-Design Prediction of Transonic Axial Compressors: Part 1 — Mean-Line Code and Tuning Factors
Authors: Kidikian John , Reggio Marcelo 
Published: August 2018

With yearly advances in CFD techniques and methodologies, and the increased capacity and capabilities of computer CPU, GPU, and information storage, CFD has become a powerful design tool. However, despite its vast strengths, a CFD analysis is still based on the sound development of the 1D mean-line analysis methodology.
This paper (part 1 of 2) describes an off-design axial compressor mean-line code, tested in a specialized engineering software for the development and analysis of a whole gas turbine engine, and the various tuning factors used to obtain an off-design performance match. It will be shown that, to obtain a proper match of the off-design performance of single-stage transonic axial compressors, both the rotor and stage pressure ratio, and the rotor temperature ratio are required to be converged upon. To do so, the off-design mean-line analysis requires the incorporation of a set of inlet & exit blockage factors and deviation angles that vary with the compressor performance conditions. This approach differs from the literature-based procedural assumptions (or rule-of-thumb) of fixed inlet and exit blockage factors of approximately “0.98”, and the use of a unique deviation angle based on Carter’s rule.
The results obtained in this paper are then used to develop a generalized off-design mean-line loss modelling methodology (part 2 of 2) capable of predicting the off-design performance of four well documented NASA transonic axial compressors.
Rig and Engine Validation of the Non-Linear Forced Response Analysis Performed by the Tool OrAgL
Authors: Hartung Andreas , Hackenberg Hans-Peter , Krack Malte , Gross Johann , Heinze Torsten , Panning-von Scheidt Lars 
Published: August 2018

Since the first non-linear forced response validation of frictionally coupled bladed disks, more than 20 years have passed, and numerous incremental modeling and simulation refinements were proposed. With the present work, we intend to assess how much we have improved since then. To this end, we present findings of an exhaustive validation campaign designed to systematically validate the non-linear vibration prediction for the different friction joints at blade roots, interlocked shrouds and under-platform dampers.
An original approach for the identification of crucial contact properties is developed. By using the Dynamic Lagrangian contact formulation and a refined spatial contact discretization, it is demonstrated that the delicate identification of contact stiffness properties can be circumvented. The friction coefficient is measured in a separate test, and determined as unique function of temperature, preload, wear state.
Rotating rig and engine measurements are compared against simulations with the tool OrAgL, developed jointly by the Leibniz Universität Hannover and the University of Stuttgart, in which state of the art Component Mode Synthesis and Harmonic Balance methods are implemented.
Post-Stall Behaviour of a Multi-Stage High Speed Compressor at Off-Design Conditions
Authors: Zhao Fanzhou , Dodds John , Vahdati Mehdi 
Published: August 2018

Stall followed by surge in a high speed compressor can lead to violent disruption of flow, damage to the blade structures and, eventually, engine shutdown. A knowledge of unsteady blade loading during such events is crucial in determining the aeroelastic stability of blade structures, experimental test of such events is however significantly limited by the potential risk and cost associated. Numerical modelling, such as unsteady CFD simulations, can provide a more informative understanding of the flow field and blade forcing during post-stall events, however very limited publications, particularly concerning multi-stage high speed compressors, can be found.
The aim of this paper is to demonstrate the possibility of using CFD for modelling full-span rotating stall and surge in a multi-stage high speed compressor, and, where possible, validate the results against experimental measurements. The paper presents an investigation into the onset and transient behaviour of rotating stall and surge in an 8-stage high speed axial compressor at off-design conditions, based on 3D URANS computations, with the ultimate future goal being aeroelastic modelling of blade forcing and response during such events. By assembling the compressor with a small and a large exit plenum volume respectively, a full-span rotating stall and a deep surge were modelled. Transient flow solutions obtained from numerical simulations showed trends matching with experimental measurements. Some insights are gained as to the onset, propagation and merging of stall cells during the development of compressor stall and surge. It is shown that surge is initiated as a result of an increase in the size of the rotating stall disturbance, which grows circumferentially to occupy the full circumference resulting in an axisymmetric flow reversal.
The Effect of Stage-Diffuser Interaction on the Aerodynamic Performance and Design of LP Steam Turbine Exhaust Systems
Authors: Ding Bowen , Xu Liping , Yang Jiandao , Yang Rui , Dai Yuejin 
Published: August 2018

Modern large steam turbines for power generation are required to operate much more flexibly than ever before, due to the increasing use of intermittent renewable energy sources such as solar and wind. This has posed great challenges to the design of LP steam turbine exhaust systems, which are critical to recovering the leaving energy that is otherwise lost. In previous studies, the design had been focused on the exhaust diffuser with or without the collector. Although the interaction between the last stage and the exhaust hood has been identified for a long time, little attention has been paid to the last stage blading in the exhaust system’s design process, when the machine frequently operates at part-load conditions.
This study focuses on the design of LP exhaust systems considering both the last stage and the exhaust diffuser, over a wide operating range. A 1/10th scale air test rig was built to validate the CFD tool for flow conditions representative of an actual machine at part-load conditions, characterised by highly swirling flows entering the diffuser. A numerical parametric study was performed to investigate the effect of both the diffuser geometry variation and restaggering the last stage rotor blades.
Restaggering the rotor blades was found to be an effective way to control the level of leaving energy, as well as the flow conditions at the diffuser inlet, which influence the diffuser’s capability to recover the leaving energy. The benefits from diffuser resizing and rotor blade restaggering were shown to be relatively independent of each other, which suggests the two components can be designed separately. Last, the potentials of performance improvement by considering both the last stage rotor restaggering and the diffuser resizing were demonstrated by an exemplary design, which predicted an increase in the last stage power output of at least 1.5% for a typical 1000MW plant that mostly operates at part-load conditions.