bluuebunny/crossref_metadata_2025 huggingface dataset:
The Oilfields Workers' Trade Union and the Challenge of Working Class Political Party Formation and Electoral Politics, 1965–1977
Authors: Vincent Godfrey
Published: November 2016

This essay undertakes an examination of the OWTU and the challenge of Working class Political Party formation and Electoral politics, 1962–2012. This area of study has been neglected by Historians and Political Scientists who have tended to focus on the narrow interpretation of the trade union. From 1965 and 1977, the OWTU played significant roles in the creation of the Workers and Farmers Party (WFP) and the United Labor Front (ULF. This essay contends that the union's involvement with these political parties was fraught with difficulties and challenges, and its efforts did not convince the working class that it was in their best interest to support the movement at the polls.
SCIENCE, RELIGION, AND THE MEANING OF LIFE AND THE UNIVERSE: “AMALGAM” NARRATIVES OF POLISH NATURAL SCIENTISTS
Authors: Rogińska Maria
Published: November 2016

This article deals with phenomena occurring at the interface of the existential, the religious, and scientific inquiry. On the basis of in‐depth interviews with Polish physicists and biologists, I examine the role that science and religion play in their narrative of the meaning of the Universe and human life. I show that the narratives about meaning have a system‐related (“amalgam") character that is associated with responses to adjacent metaphysical questions, including those based on scientific knowledge. I reconstruct the typical amalgam questions of Polish scientists and come to a conclusion about the stability of religious and nonreligious amalgams in this group. Critically referring to the thesis concerning the secularizing impact of science, I conclude that science by itself does not have a destructive effect on Polish scientists’ confidence that life and the Universe are meaningful, but is rather an exacerbating factor of the existing worldview system.
THE HUMAN HEARTH AND THE DAWN OF MORALITY
Authors: Rappaport Margaret Boone , Corbally Christopher
Published: November 2016

Stunned by the implications of Colagè's analysis of the cultural activation of the brain's Visual Word Form Area and the potential role of cultural neural reuse in the evolution of biology and culture, the authors build on his work in proposing a context for the first rudimentary hominin moral systems. They cross‐reference six domains: neuroscience on sleep, creativity, plasticity, and the Left Hemisphere Interpreter; palaeobiology; cognitive science; philosophy; traditional archaeology; and cognitive archaeology's theories on sleep changes in Homo erectus and consequences for later humans. The authors hypothesize that the human genome, when analyzed with findings from neuroscience and cognitive science, will confirm the evolutionary timing of an internal running monologue and other neural components that constitute moral decision making. The authors rely on practical modern philosophers to identify continuities with earlier primates, and one major discontinuity—some bright white moral line that may have been crossed more than once during the long and successful tenure of Homo erectus on Earth.
A CRITIQUE OF EMERGENT THEOLOGIES
Authors: Leidenhag Joanna
Published: November 2016

This article is an analysis and critique of emergent theologies, focusing on areas of Christology and pneumatology. An increasing number of Christian theologians are integrating (strong) emergence theory into their work. I argue that, despite the range of theological commitments and methodological approaches represented by these scholars, each faces similar problematic tendencies when their Christian doctrines are combined with (strong) emergence theory. It is concluded that the basic logic of emergence theory, whereby matter is seen to precede mind, makes it difficult for emergent theologies to offer an account of salvation, avoid significant issues regarding God's involvement with evil, and maintain divine transcendence. It is concluded, therefore, that Christian theology should look elsewhere for a complementary metaphysical framework with which to bridge scientific and theological discourse.
SCIENTISTS IN THE COSMOS: AN EXISTENTIAL APPROACH TO THE DEBATE BETWEEN SCIENCE AND RELIGION
Authors: Ake Stacey E.
Published: November 2016

Walker Percy's use of the terms Umwelt (environment) and Welt (symbol world) as well as his separation of events into dyadic and triadic ones, where the latter involve human beings, is brought to bear on the relationship between science and religion with the upshot being that science (a dyadic enterprise) is not equipped to really understand or explain triadic entities (namely, human beings).
WALKER PERCY, LANGUAGE, AND HOMO SINGULARIS
Authors: Sykes John D.
Published: November 2016

The novelist Walker Percy argued that modern science has a tremendous blind spot in its view of human nature. Unlike purely physical phenomena, which can be explained by the interaction of dyadic relationships, human beings must also be understood in terms of triadic relationships brought into being by symbolic language. The self brought into being by symbolic language is nonmaterial but real, and operates by different “laws” than those that govern dyadic relations. In making this case, Percy drew a sharp line between human and nonhuman language, a line that more recent developments in science has challenged. However, Percy's central point, that the agent of symbolic language cannot be understood within a materialist framework, remains valid.
EVALUATION OF DIFFERENT POLYMERIC MEMBRANE SUPPORT FOR ACETIC ACID REMOVAL BY SUPPORTED LIQUID MEMBRANE PROCESS
Authors: Harruddin Norlisa , M. Saufi Syed , M. Faizal Che Ku , Mohammad Abdul Wahab
Published: November 2016

In this study, the removal of acetic acid from aqueous solution through supported liquid membrane (SLM) process by using tri-n-octylamine (TOA) as a carrier and sodium hydroxide as a stripping agent was conducted. Acetic acid can inhibit the microbial activity during fermentation process of biomass hydrolysate, thus decreasing the bioethanol production. It is crucial to remove acetic acid prior to fermentation process in order to increase the yield of bioethanol from biomass resources. In this study, the removal of acetic acid was conducted using different types of polymeric membrane in supported liquid membrane process. Three types of polymeric membranes support which are polyethersulfone (PES), polysulfone (PSF) and polyvinyflouride (PVDF) prepared by vapour induced phase separation (VIPS) were used as a support material. The types of polymer give a significant effect on membrane morphology and its physical characteristics. PES exhibited a porous membrane support with a symmetric structure and high contact angle. Almost 86% of 10 g/l of acetic acid was successfully removed by using PES as a support membrane, compared to the 6% and 38% removal using PSF and PVDF membrane, respectively.
SURFACE WATER TREATMENT BY CUSTOM-MADE MOBILE WATER TREATMENT SYSTEM
Authors: Ramli Rosdianah , Bolong Nurmin
Published: November 2016

Advances in membrane technology have stimulated a growing interest in the development of mobile water treatment systems for rural areas lacking clean water access. This study explored the use of ultrafiltration hollow fibre (UF-HF) membranes as a filter medium in a mobile water system for surface water treatment. Prior to the surface water treatment operation, two types of UF-HF modules were prepared using different numbers of fibres (i.e. 15 and 30 fibres). By considering the effect of turbidity on the membrane permeate flux, it was found that the 30-fibre module performed with higher consistency than the module with 15 fibres within the same range of turbidity. It was observed that the specific permeate flux decreased gradually with operation time and that, simultaneously, specific permeate flux was governed by transmembrane pressure and feed water temperature. Consequently, the filtered water production was found to decrease with time. The UF-HF membrane module demonstrated good surface water treatment efficiency for a smaller-scale filter module and was able to improve surface water from water quality index (WQI) Class III to Class II.
EFFECT OF CURING TIME ON THE PORE SIZE AND EFFECTIVE THICKNESS/POROSITY OF POLYESTER THIN FILM COMPOSITE NANOFILTRATION MEMBRANES
Authors: Mah K. H. , Yussof H. W. , Abu Seman M. N. , Mohammad A. W.
Published: November 2016

Polyester thin film composite nanofiltration membranes were synthesized on the polyethersulfone (PES) support via the interfacial polymerization between triethanolamine (TEOA) and trimesoyl chloride (TMC). Here we report the effect of curing time in the interfacial polymerization process on membrane properties like pore size and effective thickness/porosity. The membrane properties were determined based on the uncharged solute permeation test and the hypothetical mechanistic structure (pore size, effective thickness/porosity) was determined using Donnan steric pore flow model (DSPM). This study also provides information on the effect of curing time on water permeability. From the 2 minute point to 10 minute point, the membranes pore sizes were reduced and negligible changes to effective thickness/porosity suggest the occurrence of additional cross-linking reaction between aqueous and organic monomers.
FOULING EFFECT ON CONTROLLER TUNING IN MEMBRANE BIOREACTOR FILTRATION PROCESS
Authors: Yusuf Zakariah , Abdul Wahab Norhaliza
Published: November 2016

This paper presents an initial investigation on controller tuning with the effect on membrane fouling in submerged membrane bioreactor (SMBR). This work employed proportional integral derivative (PID) controller to control SMBR filtration process. The PID controller is tuned using three different methods which are Ziegler Nichols (ZN), Cohen Coon (CC) and integral time-weight absolute error (ITAE) tuning. The PID controller is used to control the SMBR filtration permeate flux. Transmembrane pressure (TMP) was observed during the filtration process that will determine fouling effect on controller tuning. The simulation work is done using artificial neural network (ANN) model that was developed in our previous work.  Different set points were tested to see the robustness of the controller tuning. The overall result shows the ITAE tuning method performs better compare with other tuning methods in term of its overshoot, settling time and integral absolute error (IAE) with 0.66%, 9.1 second and 82.68 respectively. This tuning method provides precise control performance in the same time it will prevent from decrement of flux in the filtration cycle.
ELECTROSPUN NANOFIBER-COATED MEMBRANE: A REVIEW
Authors: Rosman Nurafiqah , Salleh W. N. W. , Mohamed Mohamad Azuwa , Ismail N. H. , Sazali N. , Jaafar J. , Hasbullah H.
Published: November 2016

The nanofibre development offers various useful applications in many ways including energy and environmental application. Polymeric nanofibre fabricated by electrospinning has been seen as innovative membrane materials for water remediation owing to the high surface area, interconnected porous structure, and light weight. This paper reviews the exciting functionality of nanofibre involving the development of smart heterogeneous approaches in membrane material. These heterogeneous materials allow the water molecules to spontaneously penetrate from one side to another, while blocking penetration in reverse direction due to hydrophilic-hydrophobic differences. Composite membrane containing different features arrangements of nanofibres have been utilised for their ability for water applications especially in membrane distillation.
FORMULATION OF HYBRID MEMBRANE LAYER BY USING PVA/CHITOSAN BLENDED POLYMERS ON POROUS POLYSULFONE SUPPORT, AND THE APPLICATION ON COPPER ION REMOVAL
Authors: Sulaiman Nurul Aida , Kassim Shaari Norin Zamiah , Abd Rahman Norazah , Abd Fathel Mohammad Hafizh , Elangko Aqila Zulaikha Nazreen
Published: November 2016

In this study, a thin film composite membrane was fabricated by using hybrid membrane as the barrier layer and polysulfone membrane as base membrane. During the formulation of hybrid membrane, a polymer blend of polyvinyl alcohol with chitosan was chosen as organic polymer and it was cross-linked with tetraethylorthosilicate (TEOS), where sol gel method is used to prepare the hybrid membrane. Phase inversion method is used to prepare the base membrane. The aim of this study is to determine the optimum concentration of the polymer for porous support membrane as well as the concentration of chitosan and TEOS in the fabrication of the thin film composite. Four concentrations of polysulfone (PSF) solution was prepared (13wt%, 14wt%, 15wt% and 17wt %) and the optimum concentration was determined.  For the hybrid membrane, concentration of chitosan solution was varied at1wt%, 2wt% and 3wt% with fixed concentration of polyvinyl alcohol (PVA) solution (10wt %). Results showed that 2wt% chitosan and 13 wt% PSF is sufficient to remove acceptable percentage of copper ion. For this purpose of identifying optimum amount of TEOS, pH of the feed copper ion solution was adjusted to three conditions (pH 3, 7, 10). Although, the percentage removal is highest at pH 10 but when dealing with natural integrated complexation method, pH 7 is found to be the optimum pH for the removal of copper ion. Besides that, 3 wt% TEOS in hybrid membrane has found to give a remarkable percentage removal of copper ion. Overall, a new formulation of thin film composite membrane show  a great potential to compete with those commercial membrane in thin film composite membrane application especially separation process.
STAND-ALONE WATER TREATMENT: PERFORMANCE OF ELECTROSPUN NANOFIBERS
Authors: Mataram A. , Ismail A. F. , Yuliwati E. , Matsuura T. , Rizal S. , Zamheri A.
Published: November 2016

The aim of this study was to evaluate the use of nanofiber microfiltration membranes, spun by an innovative electrospinning technique, in water filtration applications. This study bridges between developments in electrospinning techniques for the production of flat sheet membranes and the application of these membranes in water filtration. The functionalized or non-functionalized for the removal of pathogens was investigated, in term of chemical oxygen demand, total suspend solid and ammonium in the waste water. Physical properties such as clean water permeability (CWP) and strength were also examined. The results showed a very good removal of TSS (range 94.83-97.34%), COD (89.32-95.27%) and NH3­-N (64.48-72.87%). These test showed that the electrospun membranes can be used for water filtration applications.
Discrete Mechanics and Optimal Control of Walking Gaits
Authors: Koch M. W. , Ringkamp M. , Leyendecker S.
Published: November 2016

In this work, we optimally control the upright gait of a three-dimensional symmetric bipedal walking model with flat feet. The whole walking cycle is assumed to occur during a fixed time span while the time span for each of the cycle phases is variable and part of the optimization. The implemented flat foot model allows to distinguish forefoot and heel contact such that a half walking cycle consists of five different phases. A fixed number of discrete time nodes in combination with a variable time interval length assure that the discretized problem is differentiable even though the particular time of establishing or releasing the contact between the foot and the ground is variable. Moreover, the perfectly plastic contact model prevents penetration of the ground. The optimal control problem is solved by our structure preserving discrete mechanics and optimal control for constrained systems (DMOCC) approach where the considered cost function is physiologically motivated and the obtained results are analyzed with regard to the gait of humans walking on a horizontal and an inclined plane.
Evaluation of Combined Active and Passive Thermal Management Strategies for Lithium-Ion Batteries
Authors: Lopez Carlos F. , Jeevarajan Judith A. , Mukherjee Partha P.
Published: November 2016

Lithium-ion batteries are the most commonly used portable energy storage technology due to their relatively high specific energy and power but face thermal issues that raise safety concerns, particularly in automotive and aerospace applications. In these environments, there is zero tolerance for catastrophic failures such as fire or cell rupture, making thermal management a strict requirement to mitigate thermal runaway potential. The optimum configurations for such thermal management systems are dependent on both the thermo-electrochemical properties of the batteries and operating conditions/engineering constraints. The aim of this study is to determine the effect of various combined active (liquid heat exchanger) and passive (phase-change material) thermal management techniques on cell temperatures and thermal balancing. The cell configuration and volume/weight constraints have important roles in optimizing the thermal management technique, particularly when utilizing both active and passive systems together. A computational modeling study including conjugate heat transfer and fluid dynamics coupled with thermo-electrochemical dynamics is performed to investigate design trade-offs in lithium-ion battery thermal management strategies. It was found that phase-change material properties and cell spacing have a significant effect on the maximum and gradient of temperature in a module cooled by combined active and passive thermal management systems.
Enhanced Macroconvection Mechanism With Separate Liquid–Vapor Pathways to Improve Pool Boiling Performance
Authors: Kandlikar Satish G.
Published: November 2016

Understanding heat transfer mechanisms is crucial in developing new enhancement techniques in pool boiling. In this paper, the available literature on fundamental mechanisms and their role in some of the outstanding enhancement techniques is critically evaluated. Such an understanding is essential in our quest to extend the critical heat flux (CHF) while maintaining low wall superheats. A new heat transfer mechanism related to macroconvection is introduced and its ability to simultaneously enhance both CHF and heat transfer coefficient (HTC) is presented. In the earlier works, increasing nucleation site density by coating a porous layer, providing hierarchical multiscale structures with different surface energies, and nanoscale surface modifications were some of the widely used techniques which relied on enhancing transient conduction, microconvection, microlayer evaporation, or contact line evaporation mechanisms. The microconvection around a bubble is related to convection currents in its immediate vicinity, referred to as the influence region (within one to two times the departing bubble diameter). Bubble-induced convection, which is active beyond the influence region on a heater surface, is introduced in this paper as a new macroconvection mechanism. It results from the macroconvection currents created by the motion of bubbles as they grow and depart from the nucleating sites along a specific trajectory. Directing these bubble-induced macroconvection currents so as to create separate vapor–liquid pathways provides a highly effective enhancement mechanism, improving both CHF and HTC. The incoming liquid as well as the departing bubbles in some cases play a major role in enhancing the heat transfer. Significant performance improvements have been reported in the literature based on enhanced macroconvection contribution. One such microstructure has yielded a CHF of 420 W/cm2 with a wall superheat of only 1.7 °C in pool boiling with water at atmospheric pressure. Further enhancements that can be expected through geometrical refinements and integration of different techniques with macroconvection enhancement mechanism are discussed here.
Infrared Absorption Characteristics Analysis for Annulus Nanostructure of Aluminum Substrate
Authors: Hui Pan Qing , Chen Xiang , Duo Xu Sheng , Shuai Yong , Ping Tan He
Published: November 2016

An annulus-shaped nanostructure having a three-layer structure consisting of an annulus aluminum pattern, Al2O3 spacer layer, and Al substrate is presented. High absorption peaks can be easily obtained between 2.5 μm and 12.5 μm in the case of a uniform plane wave at normal incidence. A unilateral annulus structure is designed to obtain an absorption peak of almost 100% by optimal geometry parameters. Moreover, a double annulus consisting of two unilateral annuli is proposed to compare their performances. The results indicate that the double annulus inherit the single one's absorption characteristics, and that the outer loop coupling with the inner one enhances the absorption peak of the inner loop. This structure provides a great potential for application in designing selective thermal emitters, biosensing, etc.
Numerical Evaluation of AASHTO Drag Force Coefficients of Water Flow Around Bridge Piers
Authors: Almasri Amin , Moqbel Shadi
Published: November 2016

Drag force is usually exerted on bridge piers due to running river water. This force is calculated empirically based on drag coefficients stated in design codes and specifications. Different values of drag coefficients have been reported in literature. For example, AASHTO LRFD Bridge Design Specifications uses a drag coefficient of 1.4 and 0.7 for square-ended and semicircular-nosed pier, respectively, while Coastal Construction Manual (FEMA P-55) recommends a value of two and 1.2 for square and round piles, respectively. In addition, many researchers have obtained other different values of drag coefficient under similar conditions (i.e., similar range of Reynolds number) reaching to 2.6 for square object. The present study investigates the drag coefficient of flow around square, semicircular-nosed, and 90 deg wedged-nosed and circular piers numerically using finite element method. Results showed that AASHTO values for drag force coefficient varied between very conservative to be under-reckoning. The study recommends that AASHTO drag coefficient values should be revised for different circumstances and under more severe conditions.
Characterization of Particle Flow in a Free-Falling Solar Particle Receiver
Authors: Ho Clifford K. , Christian Joshua M. , Romano David , Yellowhair Julius , Siegel Nathan , Savoldi Laura , Zanino Roberto
Published: November 2016

Falling particle receivers are being evaluated as an alternative to conventional fluid-based solar receivers to enable higher temperatures and higher efficiency power cycles with direct storage for concentrating solar power (CSP) applications. This paper presents studies of the particle mass flow rate, velocity, particle-curtain opacity and density, and other characteristics of free-falling ceramic particles as a function of different discharge slot apertures. The methods to characterize the particle flow are described, and results are compared to theoretical and numerical models for unheated conditions. Results showed that the particle velocities within the first 2 m of release closely match predictions of free-falling particles without drag due to the significant amount of air entrained within the particle curtain, which reduced drag. The measured particle-curtain thickness (∼2 cm) was greater than numerical simulations, likely due to additional convective air currents or particle–particle interactions neglected in the model. The measured and predicted particle volume fraction in the curtain decreased rapidly from a theoretical value of 60% at the release point to less than 10% within 0.5 m of drop distance. Measured particle-curtain opacities (0.5–1) using a new photographic method that can capture the entire particle curtain were shown to match well with discrete measurements from a conventional lux meter.
Experimental Validation of Metaconcrete Blast Mitigation Properties
Authors: Briccola Deborah , Ortiz Michael , Pandolfi Anna
Published: November 2016

We provide experimental evidence of the mitigation properties of metaconcrete under blast loading. Mitigation is achieved through resonance of engineered aggregates consisting of a heavy and stiff core coated by a light and compliant outer layer. These engineered aggregates replace the standard gravel in conventional concrete. To assess experimentally the attenuation properties of metaconcrete, we have cast two batches of cylindrical specimens. The mortar matrix of the first batch consists of cement combined with a regular sand mix, while the mortar matrix of the second batch consists of cement combined with sand mix, fine gravel, and polymeric fibers. One of the specimens of each batch was cast with no aggregates, while the other two contained 40 and 60, respectively, randomly arranged 22 mm diameter commercially available computer mouse balls. We performed nondestructive dynamic tests by applying a 10 V amplitude periodic signal to one end of the specimens and measuring the amplitude of the transmitted signal received at the other end. We observed a remarkable 2 order of magnitude reduction in the amplitude of the transmitted signal in metaconcrete relative to conventional concrete.
Cyclic Mechanical Loading Enhances Transport of Antibodies Into Articular Cartilage
Authors: DiDomenico Chris D. , Xiang Wang Zhen , Bonassar Lawrence J.
Published: November 2016

The goal of this study was to characterize antibody penetration through cartilage tissue under mechanical loading. Mechanical stimulation aids in the penetration of some proteins, but this effect has not characterized molecules such as antibodies (>100 kDa), which may hold some clinical value for treating osteoarthritis (OA). For each experiment, fresh articular cartilage plugs were obtained and exposed to fluorescently labeled antibodies while under cyclic mechanical load in unconfined compression for several hours. Penetration of these antibodies was quantified using confocal microscopy, and finite element (FE) simulations were conducted to predict fluid flow patterns within loaded samples. Transport enhancement followed a linear trend with strain amplitude (0.25–5%) and a nonlinear trend with frequency (0.25–2.60 Hz), with maximum enhancement found to be at 5% cyclic strain and 1 Hz, respectively. Regions of highest enhancement of transport within the tissue were associated with the regions of highest interstitial fluid velocity, as predicted from finite-element simulations. Overall, cyclic compression-enhanced antibody transport by twofold to threefold. To our knowledge, this is the first study to test how mechanical stimulation affects the diffusion of antibodies in cartilage and suggest further study into other important factors regarding macromolecular transport.
Flow Field Inside a Sessile Droplet on a Hydrophobic Surface in Relation to Self Cleaning Applications of Dust Particles
Authors: Al-Sharafi Abdullah , Yilbas Bekir S. , Sahin Ahmet Z. , Ali H.
Published: November 2016

Internal fluidity of a sessile droplet on a hydrophobic surface and dynamics of fine size dust particles in the droplet interior are examined for various droplet contact angles. The geometric features of the droplet incorporated in the simulations resemble the actual droplet geometry of the experiments, and simulation conditions are set in line with the experimental conditions. The dust particles are analyzed, and the surface tension of the fluid, which composes of the dust particles and water, is measured and incorporated in the analysis. Particle tracking method is adopted experimentally to validate the numerical predictions of the flow field. It is found that heat transfer from the hydrophobic surface to the droplet gives rise to the formation of two counter rotating cells inside the droplet. The Nusselt and the Bond numbers increase with increasing droplet contact angle. The number of dust particles crossing over the horizontal rake, which corresponds to the top surface of the dust particles settled in the droplet bottom, toward the droplet interior increases as the particle density reduces, which is more pronounced in the early period. Experimental findings of flow velocity well agree with its counterparts obtained from the simulations.
A Taylor Series Expansion Approach for Nonlinear Blade Forced Response Prediction Considering Variable Rotational Speed
Authors: Heinze Torsten , Panning-von Scheidt Lars , Wallaschek Jörg , Hartung Andreas
Published: November 2016

In the field of turbomachinery, great efforts are made to enhance computational tools to obtain reliable predictions of the vibrational behavior of friction-damped bladed disks. As a trade-off between computational burden and level of simplification, numerous methods were developed to reduce the nonlinear systems dimension. Using component mode synthesis methods (CMS), one is capable to describe the systems motion by interface and modal coordinates. Subsequently or alternatively, the dynamic compliance matrix can be evaluated efficiently by means of modal superposition to avoid the inversion of the dynamic stiffness matrix. Only the equations corresponding to the degrees-of-freedom (DOF) subject to localized nonlinear contact forces need to be solved simultaneously, whereas the solution of the linear DOF is obtained by exploiting the algebraic character of the set of equations. In this paper, an approach is presented to account for rotational speed-dependent stiffness in the subset of nonlinear DOF without the need to re-evaluate the associated eigenvalue problem (EVP) when rotational speed is changed. This is done by means of a Taylor series expansion of the eigenvalues and eigenvectors used for the modal superposition to reconstruct the dynamic compliance matrix. In the context of forced response predictions of friction-damped blisks, the expansion is performed up to different order for a simplified blisk model with nonlinear contact interfaces. The results are compared to the solution obtained by direct evaluation of the EVP at selected rotational speeds and the solution when dynamic compliance matrix is built up by direct inversion of the dynamic stiffness matrix. Finally, the proposed methods computational performance is analyzed.
Decomposition of Elastic Stiffness Degradation in Continuum Damage Mechanics
Authors: Voyiadjis George Z. , Kattan Peter I.
Published: November 2016

The degradation of elastic stiffness is investigated systematically within the framework of continuum damage mechanics. Consistent equations are obtained showing how the degradation of elastic stiffness can be decomposed into a part due to cracks and another part due to voids. For this purpose, the hypothesis of elastic energy equivalence of order n is utilized. In addition, it is shown that the hypothesis of elastic strain equivalence is obtained as a special case of the hypothesis of elastic energy equivalence of order n. In the first part of this work, the formulation is scalar and applies to the one-dimensional case. The tensorial formulation for the decomposition is also presented that is applicable to general states of deformation and damage. In this general case, one cannot obtain a single explicit tensorial decomposition equation for elastic stiffness degradation. Instead, one obtains an implicit system of three tensorial decomposition equations (called the tensorial decomposition system). Finally, solution of the tensorial decomposition system is illustrated in detail for the special case of plane stress.
The Effects of Inflow Uncertainties on the Characteristics of Developing Turbulent Flow in Rectangular Pipe and Asymmetric Diffuser
Authors: Salehi Saeed , Raisee Mehrdad , Cervantes Michel J. , Nourbakhsh Ahmad
Published: November 2016

In the current paper nondeterministic computational fluid dynamics (CFD) computations of three-dimensional (3D), developing, and statistically steady turbulent flow through an asymmetric diffuser with moderate adverse pressure gradient are presented. The inflow condition is assumed to be uncertain. The inlet streamwise velocity is supposed to be a stochastic process and described by the Karhunen–Loève (KL) expansion. In addition, the inlet turbulence intensity and turbulent length scale are assumed to be uncertain. The nonintrusive polynomial chaos (NIPC) expansion is used to propagate the inflow uncertainties in the flow field. The developed code is verified using a Monte Carlo (MC) simulation with 1000 Latin Hypercube samples on a planar asymmetric diffuser. A very good agreement is observed between the results of MC and polynomial chaos expansion methods. The verified uncertainty quantification method is then applied to stochastic developing turbulent flow through a 3D asymmetric diffuser. It was observed that the eigenvalues of covariance kernel rapidly decay due to the large correlation lengths and thus a few terms in the truncated KL expansion are used to describe the stochastic inlet velocity. For the KL expansion, the mean and the standard deviation are set to those measured experimentally. The uncertain inlet condition has a significant influence on the numerical results of velocity and turbulence fields specially in the developing region before the shear layers meet. It is concluded that one of the reasons for discrepancies between experimental and deterministic CFD results is the uncertainty in inflow condition. A sensitivity analysis is also performed using the Sobol’ indices and contribution of each uncertain parameter on outputs variance is presented.
Criticality Analysis for Maintenance Purposes of Platform Supply Vessels in Remote Areas
Authors: Marhaug A. , Barabadi A. , Stagrum E. , Karlsen K. , Olsen A. , Ayele Y. Z.
Published: November 2016

The oil and gas industry is pushing toward new unexplored remote areas, potentially rich in resources but with limited industry presence, infrastructure, and emergency preparedness. Maintenance support is very important and challenging in such remote areas. A platform supply vessel (PSV) is an essential part of maintenance support. Hence, the acceptable level of its availability performance is high. Identification of critical components of the PSV provides essential information for optimizing maintenance management, defining a spare parts strategy, estimating competence needs for PSV operation, and achieving the acceptable level of availability performance. Currently, there are no standards or guidelines for the criticality analysis of PSVs for maintenance purposes. In this paper, a methodology for the identification of the critical components of PSVs has been developed, based on the available standard. It is a systematic screening process. The method considers functional redundancy and the consequences of loss of function as criticality criteria at the main and subfunction levels. Furthermore, at the component level, risk tools such as failure modes, effects and criticality analysis (FMECA), and fault tree analysis (FTA) will be applied in order to identify the most critical components. Moreover, the application of the proposed approach will be illustrated by a real case study.
Cross-Flow Vortex-Induced Vibration Simulation of Flexible Risers Employing Structural Systems of Different Nonlinearities With a Wake Oscillator
Authors: Meng Shuai , Wang Xuefeng
Published: November 2016

To achieve a reliable structural model for vortex-induced vibration (VIV) the prediction of flexible risers, this paper employs structural systems with different geometrical nonlinearities (including a linear structure, a nonlinear one, a coupled cross-flow, and axial nonlinear one) and a classical oscillator to simulate cross-flow VIV. By comparing the experimental and simulation results, it is found that when the drag coefficient is assumed to be a fixed constant along the cylinder (i.e., the damping model is linear function of current velocity), it can affect the vibration amplitude considerably and may alter the dominant modes. When the excited mode of VIV is bending-stiffness dominant, the cross-flow structural nonlinearities can have a profound stiffening effect on vibration response. Although the introduction of axial deformation can reduce this function, the coupled cross-flow and axial nonlinearities still have the effect of decreasing the VIV amplitude.
Hyperbolic Conduction–Radiation in Participating and Inhomogeneous Slab With Double Spherical Harmonics and Lattice Boltzmann Methods
Authors: Lambou Ymeli Guillaume , Tagne Kamdem Hervé Thierry
Published: November 2016

This work deals with the combined mode of non-Fourier conduction and radiation transfer in isotropically/anisotropically scattering, homogeneous, and inhomogeneous planar media with reflective boundaries subjected to the constant internal temperature of the medium and the externally isotropic diffuse incidence at one boundary. An analytical double spherical harmonics method (DPN) is proposed to solve the radiative problem. The non-Fourier conduction is described with the Cattaneo–Vernotte model, and the governing hyperbolic energy equation is solved using the lattice Boltzmann method (LBM). For radiative problems through the layer/layered media, the radiative heat fluxes, hemispherical radiative intensities, transmissivity, and reflectivity are found, while for coupled conduction and radiation, the temperature distributions are found for various optical thicknesses, space-dependent scattering albedo, conduction–radiation parameters, and boundary reflectivities. Results of the present work are in excellent agreement with those available in the literature. Moreover, these results demonstrate that the proposed analytical double spherical method is an efficient, robust, and accurate method for radiative transfer through inhomogeneous layer/layered planar media analysis. Furthermore, it is observed that space-dependent scattering albedo and boundary reflectivities have a very significant effect in the hyperbolic sharp wave front of non-Fourier conduction.
A Design Method for Orthopedic Plates Based on Surface Features
Authors: Wang Lin , He Kunjin , Chen Zhengming , Yang Yin
Published: November 2016

Matching of orthopedic plates and bony surfaces does not have a high certainty of success because bone anatomy differs among individuals. Considering that surfaces of both orthopedic plates and bones manifest themselves as freeform surfaces and are especially suitable for surface feature-based design, a novel surface feature-based method for designing orthopedic plates is put forward, with detailed steps as follows. First, the bone surface feature (BSF) is established through feature representation of an average bone surface model, obtained based on the investigated samples. Second, the abutted surface of an orthopedic plate is established directly based on the BSF surface to increase matching between the plate and bony surface. The abutted surface feature (ASF) is then established through feature representation of the abutted surface. Third, the hierarchical mapping relationship between BSF and ASF is setup based on the framework of “three-level parameters and two-grade mappings.” The result is that semantic parameters defined on BSF and ASF are separated as an operation interface to make it convenient to edit orthopedic plates according to bone sizes. Finally, the orthopedic plate is generated by thickening the abutted surface, which is generated based on parameters defined on BSF. Taking radius as an example, a group of volar plates suitable for distal radius with different sizes are generated, showing that the proposed method is valid and feasible. Meanwhile, biomechanical stresses of designed volar plates are analyzed with finite element analysis, and the result shows that designed volar plates have good structural strength.
Dynamics of Slant Cracked Rotor for a Steam Turbine Generator System
Authors: Liu Chao , Jiang Dongxiang
Published: November 2016

Root causes of several recent crack failures in turbine units are attributed to oscillation and interaction between generator of turbine unit and devices on the grid, where torsional vibration of the rotor bearing system is observed and identified as an important cause. Exploring vibrational (lateral, torsional, and axial) features in the cracked rotor system with torsional excitation (TE) present can provide a novel view in crack detection and isolation. This work presents dynamic analysis of a cracked rotor system in a steam turbine unit (a typical rotor system with multiple rotors, multiple supports, and oscillating loads), and the vibrational features of the cracked rotor system with comparisons to typical features in monitored vibration data. The results show that coupled vibration in both lateral and torsional components is an effective indicator for cracks in the presence of torsional excitation. Also, vibration characteristics evaluated in different locations of the rotor system are beneficial for fault detection and isolation.
A Comparison of 1D-3D Co-Simulation and Transient 3D Simulation for EGR Distribution Studies
Authors: Dimitriou P. , Avola C. , Burke R. , Copeland C. , Turner N.
Published: December 2016

Computational modeling, an important task for design, research and development stages, is evolving fast with the increase of computational capabilities over the last decades. One-dimensional (1D) CFD simulation is commonly used to analyze the flow rates and pressures of an entire fluid system of interconnected parts such as pipes, junctions, valves, and pumps. In contrast, three-dimensional (3D) CFD simulation allows detailed modeling of components such as manifolds, heat exchangers, and combustion cylinders where the flow contains significant 3D effects. Coupling a 1D model with a 3D domain potentially offers the benefits of both simulation strategies in one co-simulation approach.

The present study provides a deep understanding of the co-simulation approach by listing all necessary steps need to be followed before and during the coupling of the 1D and 3D simulation software. It analyses the simulation and convergence time requirements based on the 3D model mesh quality and compares this approach with the current 1D–3D uncoupled approach followed in the industry. The outputs of both simulation approaches are then compared with experimental results.

The co-simulation time mainly depends on the mesh quality of the 3D domain and the number of inner iterations per time-step which is entirely determined by the nature and complexity of the simulation. The co-simulation time per engine cycle is almost identical to the uncoupled approach. However, it was found that the number of cycles required for convergence in the coupled approach is nearly double than the uncoupled approach. The comparison between the two simulation approaches and the experimental results demonstrated the very 3D nature of the flows, the sensitivity of the uncoupled approach to input conditions and the sensitivity of co-simulation to the averaged boundary conditions transferred from the 1D model back to the 3D domain.
Parametric Study of Ignition and Combustion Characteristics From a Gasoline Compression Ignition Engine Using Two Different Reactivity Fuels
Authors: Cung Khanh , Rockstroh Toby , Ciatti Stephen , Cannella William , Goldsborough S. Scott
Published: December 2016

Unlike homogeneous charge compression ignition (HCCI) that has the complexity in controlling the start of combustion event, partially premixed combustion (PPC) provides the flexibility of defining the ignition timing and combustion phasing with respect to the time of injection. In PPC, the stratification of the charge can be influenced by a variety of methods such as number of injections (single or multiple injections), injection pressure, injection timing (early to near TDC injection), intake boost pressure, or combination of several factors. The current study investigates the effect of these factors when testing two gasoline-like fuels of different reactivity (defined by Research Octane Number or RON) in a 1.9-L inline 4-cylinder diesel engine. From the collection of engine data, a full factorial analysis was created in order to identify the factors that most influence the outcomes such as the location of ignition, combustion phasing, combustion stability, and emissions. Furthermore, the interaction effect of combinations of two factors or more was discussed with the implication of fuel reactivity under current operating conditions. The analysis was done at both low (1000 RPM) and high speed (2000 RPM). It was found that the boost pressure and air/fuel ratio have strong impact on ignition and combustion phasing. Finally, injection-timing sweeps were conducted whereby the ignition (CA10) of the two fuels with significantly different reactivity were matched by controlling the boost pressure while maintaining a constant lambda (air/fuel equivalence ratio).
Combustion Characteristics of Methane Direct Injection Engine Under Various Injection Timings and Injection Pressures
Authors: Song Jingeun , Choi Mingi , Kim Daesik , Park Sungwook
Published: December 2016

The performance of a methane direct injection engine was investigated under various fuel injection timings and injection pressures. A single-cylinder optical engine was used to acquire in-cylinder pressure data and flame images. An outward-opening injector was installed at the center of the cylinder head.

Experimental results showed that the combustion characteristics were strongly influenced by the end of injection timing rather than the start of injection timing. Late injection enhanced the combustion speed because the short duration between the end of injection and the spark induced strong turbulence. The flame propagation speeds under various injection timings were directly compared using crank-angle-resolved sequential flame images. The injection pressure was not an important factor in the combustion; the three injection pressure cases of 0.5, 0.8, and 1.1 MPa yielded similar combustion trends. In the cases of late injection, the injection timings of which were near the Intake Valve Closing (IVC) timing, the volumetric efficiency was higher (by 4%) than in the earlier injection cases. This result implies that the methane direct injection engine can achieve higher torque by means of the late injection strategy.
Carbon Fiber Reinforcement of a Water Storage Tank for Beyond Design Basis Loads
Authors: Reich Alton , Charest John
Published: December 2016

The severe damage to the Fukushima nuclear plant occurred as a result of a beyond design basis event. This has prompted a systematic review of safety critical systems at US nuclear power plants to evaluate the existing safety margin based on beyond design basis loads.

At one US nuclear power plant it was found that the Refueling Water Storage Tank (RWST) did not have sufficient margin to withstand the defined beyond design basis seismic event. An analysis indicated that the RWST would fail in an elephant foot buckling mode. This paper describes the design and analysis of a Carbon Fiber Reinforced Polymer (CFRP) repair system used to strengthen the RWST to increase the critical buckling stress for the elephant foot buckling mode.
Seismic Quantitative Risk Assessment of Process Plants Through Monte Carlo Simulations
Authors: Alessandri Silvia , Caputo Antonio C. , Corritore Daniele , Giannini Renato , Paolacci Fabrizio
Published: December 2016

This paper describes the application of Monte Carlo method for the quantitative seismic risk assessment (QSRA) of process plants. Starting from the seismic hazard curve of the site where the plant is located, the possible chains of accidents are modelled using a sequence of propagation levels in which Level 0 is represented by the components directly damaged by the earthquake whereas the subsequent Levels represent the resulting consequence propagation. In greater detail all units damaged by energy and materials releases from level 0 units are included in level 1 and so forth, so that referring to process units belonging to a generic i-th Level, they are damaged by level (i-1) units and damage units of level (i+1). The sequence of levels represents the damage propagation across the plant through any multiple interacting sequences of accidents. For each unit a damage (DM) - loss of containment (LOC) matrix is generated allowing to estimate the amount of energy and material releases as well as resulting physical effects based on which the scenario at i-th level is generated. The process stops when no further damage propagation is allowed.