bluuebunny/crossref_metadata_2025 huggingface dataset:
Holding Polluting Countries to Account for Climate Change: Is “Loss and Damage” Up to the Task?
Authors: Johnson Craig A.
Published: November 2016

Formally established by the Conference of the Parties to the UN Framework Convention on Climate Change in 2013, the Loss and Damage Mechanism represents what is for many an important effort on the part of developing countries (including China and the G77) to hold polluting countries to account for past and potential harms incurred as a result of climate change. This paper explores the viability of using the Mechanism as a means of holding polluting countries to account for the provisions outlined in the Framework Convention. In reviewing the history and recent policy within the UNFCCC, the paper makes the case that demands for greater accountability through the Loss and Damage Mechanism have been frustrated by a lack of consensus about the rights of poor countries to pursue carbon‐intensive development pathways, the obligations of current and future generations to the actions and decisions of their forebears, and the obligations of national governments to their own citizens and the UNFCCC. Instead of assigning responsibility for past and future losses and damages, the Mechanism has gravitated toward a more technocratic/bureaucratic exercise aimed at collecting data, enhancing knowledge, and making policy recommendations.
Blatant, Subtle, and Insidious: URM Faculty Perceptions of Discriminatory Practices in Predominantly White Institutions
Authors: Zambrana Ruth Enid , Harvey Wingfield Adia , Lapeyrouse Lisa M. , Dávila Brianne A. , Hoagland Tangere L. , Valdez Robert Burciaga
Published: November 2016

Although modest gains are observed in the number of African American, Mexican American, and Puerto Rican faculty in higher education institutions, systemic issues of underrepresentation and retention remain problematic. This article describes how historically underrepresented minority (URM) faculty in Predominantly White Institutions perceive discrimination and illustrates the ways in which discriminatory institutional practices—such as microaggressions—manifest and contribute to unwelcoming institutional climates and workplace stress. Using a mixed methods approach, including survey data and individual and group interviews, findings show that respondents (n = 543) encounter racial discrimination from colleagues and administrators; experience discrimination differently based on their race/ethnicity and gender; and report difficulties in describing racist encounters. Qualitative data reveal three themes that inform the survey results on perceived discrimination: (1) blatant, outright, subtle, and insidious racism; (2) devaluation of scholarly contributions, merit, and skillset by colleagues and administrators; and (3) the burden of “representing minorities,” or a “racial/ethnic tax.” Propositions for how to change unwelcoming environments and create safe spaces for professional development to reduce the adverse effects of discrimination among URM faculty are discussed.
Detection of HLA‐C*04:247, a novel HLA‐C*04 variant, in a Taiwanese hematopoietic stem cell donor
Authors: Yang K. L. , Lin P. Y.
Published: November 2016

One nucleotide replacement at residue 511 of the HLA‐C*04:01:01:01 results in a novel allele, HLA‐C*04:247.
Validation of the multiplex ligation‐dependent probe amplification assay and its application on the distribution study of the major alleles of 17 blood group systems in Chinese donors from Guangzhou
Authors: Ji Yanli , Wen Jizhi , Veldhuisen Barbera , Haer‐Wigman Lonneke , Wang Zhen , Lodén‐van Straaten Martin , Wei Ling , Luo Guangping , Fu Yongshui , van der Schoot C. Ellen
Published: November 2016

BACKGROUND

Genotyping platforms for common red blood cell (RBC) antigens have been successfully applied in Caucasian and black populations but not in Chinese populations. In this study, a genotyping assay based on multiplex ligation‐dependent probe amplification (MLPA) technology was applied in a Chinese population to validate the MLPA probes. Subsequently, the comprehensive distribution of 17 blood group systems also was obtained.

STUDY DESIGN AND METHODS

DNA samples from 200 Chinese donors were extracted and genotyped using the blood‐MLPA assay. To confirm the MLPA results, a second independent genotyping assay (ID Core+) was conducted in 40 donors, and serological typing of 14 blood‐group antigens was performed in 91 donors. In donors who had abnormal copy numbers of an allele (DI and GYPB) determined by MLPA, additional experiments were performed (polymerase chain reaction, sequencing, and flow cytometry analysis).

RESULTS

The genotyping results obtained using the blood‐MLPA and ID Core+ assays were consistent. Serological data were consistent with the genotyping results except for one donor who had a Lu(a−b−) phenotype. Of the 17 blood group systems, the distribution of the MNS, Duffy, Kidd, Diego, Yt, and Dombrock systems was polymorphic. The Mur and Sta antigens of the MNS system were distributed with a frequency of 9% (18 of 200) and 2% (4 of 200), respectively. One donor with chimerism and one who carried a novel DI*02(A845V) allele, which predicts the depression of Dib antigen expression, were identified.

CONCLUSIONS

The blood‐MLPA assay could easily identify the common blood‐group alleles and correctly predicted phenotype in the Chinese population. The Mur and Sta antigens were distributed with high frequency in a Southern Chinese Han population.
Lecane tenuiseta rotifers improves activated sludge settleability in laboratory scale SBR system at 13°C and 20°C
Authors: Kocerba‐Soroka Wioleta , Fiałkowska Edyta , Pajdak‐Stós Agnieszka , Sobczyk Mateusz , Starzycka Joanna , Fyda Janusz
Published: November 2016

Two experiments at different temperatures were conducted in five laboratory‐scale bioreactors with enhanced nutrient removal simulating the work of sequencing batch reactors (SBRs). The process was operated in three 8‐hour cycles. The oxygen concentration, pH and temperature were controlled and maintained at 1 mg of O2/L, 7 and 13°C, respectively, throughout the first two weeks and at 20°C for the next 10 days. The introduction of Lecane tenuiseta improved the settling properties of the activated sludge dominated by Microthrix parvicella at both temperatures tested. L. tenuiseta rotifers led to a reduction in filamentous bacteria abundance and did not negatively affect the chemical parameters of the effluent. For each temperature, there were no differences in COD, Ntot, N‐NH4 or P‐PO4 values between the treatment and control bioreactors. The results have shown that the application of L. tenuiseta is a promising biological tool for bulking prevention especially in a cold season.
LIFE ON THE ISLAND
Authors: Corey Elizabeth
Published: November 2016

Walker Percy was both a medical doctor and a serious Catholic—a scientist and a religious believer. He thought, however, that science had become hegemonic in the twentieth century and that it was incapable of answering the most fundamental needs of human beings. He thus leveled a critique of the scientific method and its shortcomings in failing to address the individual person over against the group. In response to these shortcomings Percy postulates a religious understanding of human life, one in which man's life is understood as a pilgrimage or a search. The person who searches may not find the “object” of his search during his earthly life, but it is likely that he will come to a better understanding of himself by means of it.
PHILOSOPHER OF PRECISION AND SOUL: INTRODUCING WALKER PERCY
Authors: Marsh Leslie
Published: November 2016

This article introduces the work of philosopher‐novelist Walker Percy to the Zygon: Journal of Religion and Science readership. After some biographical and contextual preliminaries, I suggest that the conceptual collecting feature to Percy's work is his critique of abstractionism manifest in a tripartite congruence of Cartesianism, derivatively misapplied science, and social atomism.
EFFECT OF PMMA-MWNTS LOADING ON CO2 SEPARATION PERFORMANCE OF THIN FILM NANOCOMPOSITE MEMBRANE
Authors: Kar Chun Wong , Pei Sean Goh , Fauzi Ismail Ahmad
Published: November 2016

Nanocomposite membrane, especially the thin film nanocomposite (TFN) fabricated via interfacial polymerization (IP) is a relatively new class of membrane which features good separation performance and practical processing. This study investigated on the effects of multi-walled carbon nanotubes (MWNTs) loading on the gas separation performance of the resultant TFNs. TFNs were tested with pure CO2, N2 and CH4 gases at feed pressure of 2 bar. The findings from this study suggested that the optimum fillers loading was around 0.25 g/L in the coating solution which gives TFN with CO2 permeance of 53.5 gas permeation unit (GPU) (12% higher than base membrane without filler), CO2/N2 selectivity of 61 and CO2/CH4 selectivity of 35. The enhancement in CO2 permeance without sacrificing the membrane selectvities was attributed to the good dispersion and compatibility of the MWNTs with the polymer matrix while the nanotubes serve as rapid diffusion channels to facilitate transport of gases. TFN embedded with polymethyl methacrylate (PMMA)-MWNTs showed potential for low pressure carbon capture and storage application.
Cortical and reticular contributions to human precision and power grip
Authors: Tazoe Toshiki , Perez Monica A.
Published: November 2016

Key points

The corticospinal tract contributes to the control of finger muscles during precision and power grip. We explored the neural mechanisms contributing to changes in corticospinal excitability during these gripping configurations.

Motor evoked potentials (MEPs) elicited by cortical, but not by subcortical, stimulation were more suppressed during power grip compared with precision grip and index finger abduction.

Intracortical inhibition was more reduced during power grip compared with the other tasks. An acoustic startle cue, a stimulus that engages the reticular system, suppressed MEP size during power grip to a lesser extent than during the other tasks at a cortical level and this positively correlated with changes in intracortical inhibition.

Our findings suggest that changes in corticospinal excitability during gross more than fine finger manipulations are largely cortical in origin and that the reticular system contributed, at least in part, to these effects.

It is well accepted that the corticospinal tract contributes to the control of finger muscles during precision and power grip in humans but the neural mechanisms involved remain poorly understood. Here, we examined motor evoked potentials elicited by cortical and subcortical stimulation of corticospinal axons (MEPs and CMEPs, respectively) and the activity in intracortical circuits (suppression of voluntary electromyography) and spinal motoneurons (F‐waves) in an intrinsic hand muscle during index finger abduction, precision grip and power grip. We found that the size of MEPs, but not CMEPs, was more suppressed during power grip compared with precision grip and index finger abduction, suggesting a cortical origin for these effects. Notably, intracortical inhibition was more reduced during power grip compared with the other tasks. To further examine the origin of changes in intracortical inhibition we assessed the contribution of the reticular system, which projects to cortical neurons, and projects to spinal motoneurons controlling hand muscles. An acoustic startle cue, which engages the reticular system, suppressed MEP size during power grip to a lesser extent than during the other tasks and this positively correlated with changes in intracortical inhibition. A startle cue decreased intracortical inhibition, but not CMEPs, during power grip. F‐waves remained unchanged across conditions. Our novel findings show that changes in corticospinal excitability present during power grip compared with fine finger manipulations are largely cortical in origin and suggest that the reticular system contributed, at least in part, to these effects.
Role of TRPM7 in cerebral ischaemia and hypoxia
Authors: Sun Hong‐Shuo
Published: November 2016

Transient receptor potential melastatin 7 (TRPM7) channel, a calcium‐permeable non‐selective divalent cation channel, is broadly expressed in various cells and tissues, including the brain. TRPM7 is thought to be coupled to the metabolic state and regulate calcium homeostasis in the cell. TRPM7 takes part in a wide range of cell biology processes that affect cell growth and proliferation, as well as in embryonic development and skeleton formation. TRPM7 plays a significant role in ischaemic and hypoxic brain injury and neuronal cell death. TRPM7, as a key non‐glutamate mechanism of cerebral ischaemia, also triggers an intracellular ionic imbalance and neuronal cell death in ischaemia and hypoxia. We have reported that TRPM7 is expressed in neurons of the hippocampus and cortex and activation of TRPM7 induced ischaemic neuronal cell death; suppression of TRPM7 with virally mediated gene silencing using siRNA reduced ischaemic neuronal cell death and improved neurobehavioural outcomes in vivo. Recently, we also demonstrated that inhibition of TRPM7 using pharmacological means promoted neuronal outgrowth in vitro and provided neuroprotection against brain injury to hypoxia in vivo. Thus, we have shown the contributions of TRPM7 in many physiological and pathophysiological processes, including hypoxia and ischaemia.

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Sub-Beam Size Temperature Measurement of Heavily Doped Silicon Heater Using Two-Wavelength Thermoreflectance Microscopy
Authors: Rho Jinsung , Jae Lee Bong
Published: November 2016

This work describes a novel technique for simultaneously determining local temperature and thickness of a heavily doped Si heater having a submicron width by using two-wavelength thermoreflectance microscopy. The doped silicon line heater, whose thickness and width are, respectively, 480 nm and 900 nm, is fabricated by conventional microfabrication techniques on a fused silica wafer. The full width at half maximum (FWHM) of the focused laser beam is measured to be 2.00 μm and 2.28 μm for green (λ = 516 nm) and red (λ = 640 nm) lasers, respectively. Because the heater width is narrower than the focused laser beam size, the reflected beam contains background information (i.e., reflection from the fused silica substrate) in addition to the thermoreflectance signal from the doped silicon heater. With precise knowledge of the laser beam size, heater width, and exact location of the laser beam spot on the heater, one can quantitatively model the reflectance. In reality, however, due to the difficulty of aligning the laser beam with respect to the submicron-wide Si heater, precise determination of local temperature from thermoreflectance signal is not easily attained. In the present study, instead of aligning the laser beam to the center of the submicron silicon heater, the probe laser horizontally scans over a region of the heater. By taking into account the size of the focused laser beam and the width of the doped silicon heater, it is possible to determine the absolute temperature of a local region of the heater from the measured reflectance during the scanning, even though the width of the heater line is only 39% of the size of the laser beam.
Experimental Study and Application of Steam Flooding for Horizontal Well in Ultraheavy Oil Reservoirs
Authors: Liu Pengcheng , Zheng Hemei , Wu Guanhuan
Published: November 2016

Based on the ultraheavy oil area in AL-1 Block, Shengli Oilfield, China, a two-dimensional (2D) high-temperature–high-pressure (HTHP) visualized scaled physical simulation system was constructed to investigate intensively oil displacement mechanisms underlying steam flooding for horizontal well at different development stages. The results indicated that whole process is divided into three phases: water extraction phase, steam effective displacement phase, and steam breakthrough phase. Different phases have different oil displacement mechanisms. These differences are caused mainly by the synthetic actions of horizontal displacement and vertical drainage. A series of physical experiments were conducted to evaluate the optimal parameters affecting the development effects of steam flooding for horizontal wells. The results indicated that the development effect at the pressure of 5 MPa is better than that at 7 MPa when the steam dryness at the bottom of the well was 0.6; the steam dryness at the bottom should be kept above 0.4; the steam chamber was fully expanded at the injected intensity of steam of 1.9 ton/(d. ha. m). Increasing steam dryness under high-pressure conditions can facilitate an effective development. The results were successfully used to guide 18 horizontal wells from AL-1 Block, and the data collected here may provide important guidance for steam flooding in heavy or ultraheavy oil reservoir.
Measurements of Hydrogen-Enriched Combustion of JP-8 in Open Flame
Authors: Seibert Michael , Nieh Sen
Published: November 2016

Hydrogen enrichment is presented as a control parameter to improve JP-8 combustion. Research in fuel reforming gives an opportunity for hydrogen production at the point of use. Hydrogen-enriched combustion of JP-8 seeks to take advantage of the energy density of JP-8 and the combustibility of hydrogen. At low power output (<2 kWe), technologies such as Stirling engines, thermoelectric, and thermophotovoltaic generators have the potential to compete with diesel engines, but require reliable JP-8 combustion. Experiments were conducted with atomized JP-8 in a 5 kWth open flame, based on a 500 W power source. JP-8 is sprayed through an air-atomizing nozzle. Hydrogen was added to either the atomizing air or to a concentric tube supplying the main combustion air. In these experiments, hydrogen represented up to 26% of the fuel energy contribution (EC). During hydrogen enrichment, JP-8 flow rate was reduced to maintain constant fuel energy input. Temperature is measured vertically and laterally through the flame. Temperature profiles show that combustion shifts toward the nozzle as hydrogen is added. Hydrogen in the secondary air maintains diffusion flame behavior, but earlier in the flame. Hydrogen in the nozzle air creates a premixed pilot flame structure in the center of the flame. This premixed hydrogen and air flame provides initial energy to speed droplet heating and vaporization, producing higher peak temperatures than the other cases studied. Gaseous emissions are measured above the visible flame. Hydrogen enrichment by both methods reduced unburned hydrocarbon emissions by up to 70%. The advantages provided by hydrogen enrichment represent opportunities for reduced size, improved operational reliability and control, and reduced pollutant emissions.
Use of Computational Combustion in the Development and Design of Energy-Efficient Household Cooker-Top Burners
Authors: Bedii Özdemir İ.
Published: November 2016

In order to design energy efficient cooker-top burners, the stabilization mechanisms of partially premixed flames were investigated. Different design features are assessed with the identical fuel (CH4), fuel flow rate, and load vessel arrangement, but with different levels of primary aeration and flame delivery. k–ε Reynolds-averaged Navier–Stokes (RANS) simulations are performed using the modified temperature-composition pdf method and the intrinsic low-dimensional manifold (ILDM) reduction scheme. The results show that the optimum value of the angle of flame delivery is about 30–35 deg. The contact area of the flame cup under the bottom surface depends on the diameter of the burner head which determines the separation of the flames. The traditional solution to reduce the port separations, which is to increase the number of ports, is shown to cause weak flames which extinguish in shorter distances and can have strong tendency to blow off. It also causes significant pressure resistance ahead of the contraction tube and so impairs the primary aeration. In the present study, a new slot profile, named the double-V form, is proposed and shown to be very effective in reducing the gaps between the flames, without creating any further pressure resistance.
The State of the Art and Challenges in Geomechanical Modeling of Injector Wells: A Review Paper
Authors: Bautista J. F. , Dahi Taleghani A.
Published: November 2016

Fluid injection is a common practice in the oil and gas industry found in many applications such as waterflooding and disposal of produced fluids. Maintaining high injection rates is crucial to guarantee the economic success of these projects; however, there are geomechanical risks and difficulties involved in this process that may threat the viability of fluid injection projects. Near wellbore reduction of permeability due to pore plugging, formation failure, out of zone injection, sand production, and local compaction are challenging the effectiveness of the injection process. Due to these complications, modeling and simulation has been used as an effective tool to assess injectors' performance; however, different problems have yet to be addressed. In this paper, we review some of these challenges and the solutions that have been proposed as a primary step to understand mechanisms affecting well performance.
Study of Cholesterol Repletion Effect on Nanomechanical Properties of Human Umbilical Vein Endothelial Cell Via Rapid Broadband Atomic Force Microscopy
Authors: Yan Bo , Ren Juan , Liu Yue , Huang Huarong , Zheng Xi , Zou Qingze
Published: November 2016

Abnormalities of blood cholesterol concentration are associated with increased risks for vascular disease, especially heart attacks and strokes. As one of the main lipid components of plasma membrane in all mammalian cells, cholesterol has a major impact on the mechanical properties of the membrane of endothelial cells. Although the effect of cholesterol depletion on cell mechanical properties has been studied, no results yet have been reported on quantitative investigation of cholesterol repletion effect. In this study, the cholesterol repletion effect on the nanomechanical properties of human umbilical vein endothelial cell (EA.hy926) was studied using a control-based atomic force microscope (AFM) nanomechanical measurement protocol. The viscoelasticity of EA.hy926 cells were measured over a large frequency range (0.1–100 Hz) using both constant-rate excitation force with different loading rates and a broadband excitation force. The viscoelasticity oscillation of the cell membranes under the cholesterol effect was also monitored in real-time. The experiment results showed that under the effect of cholesterol repletion, both the Young's modulus and the complex modulus of EA.hy926 cell were increased over 30%, respectively, and moreover, the amplitudes of both the elasticity oscillation and the viscosity oscillation at a period of around 200 s were increased over 70%, respectively. Therefore, this work is among the first to investigate the mechanical properties, particularly, the broadband viscoelasticity variations of EA.hy926 cells under cholesterol repletion treatment. The results revealed that cholesterol repletion may reinforce the coupling of F-actin to plasma membrane by increasing actin stability, and the cholesterol might have modified the submembrane cytoskeletal organization of EA.hy926 cell by causing the involvement of the motor protein nonmuscle myosin II.
Histology and Biaxial Mechanical Behavior of Abdominal Aortic Aneurysm Tissue Samples
Authors: Pancheri Francesco Q. , Peattie Robert A. , Reddy Nithin D. , Ahamed Touhid , Lin Wenjian , Ouellette Timothy D. , Iafrati Mark D. , Luis Dorfmann A.
Published: November 2016

Abdominal aortic aneurysms (AAAs) represent permanent, localized dilations of the abdominal aorta that can be life-threatening if progressing to rupture. Evaluation of risk of rupture depends on understanding the mechanical behavior of patient AAA walls. In this project, a series of patient AAA wall tissue samples have been evaluated through a combined anamnestic, mechanical, and histopathologic approach. Mechanical properties of the samples have been characterized using a novel, strain-controlled, planar biaxial testing protocol emulating the in vivo deformation of the aorta. Histologically, the tissue ultrastructure was highly disrupted. All samples showed pronounced mechanical stiffening with stretch and were notably anisotropic, with greater stiffness in the circumferential than the axial direction. However, there were significant intrapatient variations in wall stiffness and stress. In biaxial tests in which the longitudinal stretch was held constant at 1.1 as the circumferential stretch was extended to 1.1, the maximum average circumferential stress was 330 ± 70 kPa, while the maximum average axial stress was 190 ± 30 kPa. A constitutive model considering the wall as anisotropic with two preferred directions fit the measured data well. No statistically significant differences in tissue mechanical properties were found based on patient gender, age, maximum bulge diameter, height, weight, body mass index, or smoking history. Although a larger patient cohort is merited to confirm these conclusions, the project provides new insight into the relationships between patient natural history, histopathology, and mechanical behavior that may be useful in the development of accurate methods for rupture risk evaluation.
The Localized Hemodynamics of Drug-Eluting Stents Are Not Improved by the Presence of Magnetic Struts
Authors: Vijayaratnam P. R. S. , Barber T. J. , Reizes J. A.
Published: November 2016

The feasibility of implementing magnetic struts into drug-eluting stents (DESs) to mitigate the adverse hemodynamics which precipitate stent thrombosis is examined. These adverse hemodynamics include platelet-activating high wall shear stresses (WSS) and endothelial dysfunction-inducing low wall shear stresses. By magnetizing the stent struts, two forces are induced on the surrounding blood: (1) magnetization forces which reorient red blood cells to align with the magnetic field and (2) Lorentz forces which oppose the motion of the conducting fluid. The aim of this study was to investigate whether these forces can be used to locally alter blood flow in a manner that alleviates the thrombogenicity of stented vessels. Two-dimensional steady-state computational fluid dynamics (CFD) simulations were used to numerically model blood flow over a single magnetic drug-eluting stent strut with a square cross section. The effects of magnet orientation and magnetic flux density on the hemodynamics of the stented vessel were elucidated in vessels transporting oxygenated and deoxygenated blood. The simulations are compared in terms of the size of separated flow regions. The results indicate that unrealistically strong magnets would be required to achieve even modest hemodynamic improvements and that the magnetic strut concept is ill-suited to mitigate stent thrombosis.
Blast Responses of Bridge Girders With Consideration of Isolation Effect Induced by Car Bomb
Authors: Hu Zhijian , Zhang Yifeng , Zeng Zhen , Sun L. Z.
Published: November 2016

Car bomb attack exhibits considerable different effects on structures when compared with the bare explosive blast. In this paper, a postdisaster investigation is presented for an existing bridge under accidental car bomb blast loading. Based on the analysis of the explosive properties, the crack distribution and deformation of the blast loaded girders are studied. Numerical analysis is conducted to verify the findings by simulating the truck isolation effect with steel plate. Both field data and numerical results indicate that the isolation effect of the vehicle can significantly affect the blast loading distribution on structures. Specifically, the shock wave propagation is isolated directly under the explosive source with the delayed arriving time. Peak values of overpressure within the steel plate isolating region are diminished while the pressures are magnified outside the isolating region due to reflection and wave merging. The results can be applicable to determine the essential blast-resistant design criteria to reduce the probability of blast induced failures.
Comparison of Two-Dimensional and Three-Dimensional Turbine Airfoils in Combination With Nonaxisymmetric Endwall Contouring
Authors: Zimmermann Tobias W. , Curkovic Oliver , Wirsum Manfred , Fowler Andrew , Patel Kush
Published: November 2016

Tangential endwall contouring (TEWC) is intended to improve the turbomachinery blading efficiency. This paper summarizes the experimental and numerical investigation of a test turbine with endwall contoured vanes and blades. Constant section (2D) airfoils as well as optimized compound lean (3D) high pressure steam turbine blading in baseline and endwall contoured configurations have been examined. Brush seals (BSs) are implemented within the casing sided cavities to minimize the leakage flow near the tip endwalls, where the contouring is also applied. The pressure and temperature data that are recorded in three axial measuring planes are plotted to visualize the change in flow structure. This shows that the efficiency is increased for 2D airfoils by means of endwall contouring. However, the efficiency of the first stage suffers, and the endwall contouring is still beneficial for the overall performance of the engine. Both phenomena (an efficiency loss in stage one and an improvement of the performance in stage two) have also been measured for the optimized 3D configurations; thus, it can be expected that the endwall contouring has also a beneficial impact on the performance of multirow turbines. The numerical investigations demonstrate in detail, how the secondary flow phenomena are influenced by end-wall contouring and a description of the changes in vortex formations as well as blade loading are given for the various configurations. It has been found that for steady computational fluid dynamics (CFD) simulations the use of stage interfaces suppresses the positive effects of the endwall contour onto the downstream blade row.
Effects of Double Wall Cooling Configuration and Conditions on Performance of Full-Coverage Effusion Cooling
Authors: Rogers Nathan , Ren Zhong , Buzzard Warren , Sweeney Brian , Tinker Nathan , Ligrani Phil , Hollingsworth Keith , Liberatore Fred , Patel Rajeshriben , Ho Shaun , Moon Hee-Koo
Published: November 2016

Experimental results are presented for a double wall cooling arrangement which simulates a portion of a combustor liner of a gas turbine engine. The results are collected using a new experimental facility designed to test full-coverage film cooling and impingement cooling effectiveness using either cross flow, impingement, or a combination of both to supply the film cooling flow. The present experiment primarily deals with cross flow supplied full-coverage film cooling for a sparse film cooling hole array that has not been previously tested. Data are provided for turbulent film cooling, contraction ratio of 1, blowing ratios ranging from 2.7 to 7.5, coolant Reynolds numbers based on film cooling hole diameter of about 5000–20,000, and mainstream temperature step during transient tests of 14 °C. The film cooling hole array consists of a film cooling hole diameter of 6.4 mm with nondimensional streamwise (X/de) and spanwise (Y/de) film cooling hole spacing of 15 and 4, respectively. The film cooling holes are streamwise inclined at an angle of 25 deg with respect to the test plate surface and have adjacent streamwise rows staggered with respect to each other. Data illustrating the effects of blowing ratio on adiabatic film cooling effectiveness and heat transfer coefficient are presented. For the arrangement and conditions considered, heat transfer coefficients generally increase with streamwise development and increase with increasing blowing ratio. The adiabatic film cooling effectiveness is determined from measurements of adiabatic wall temperature, coolant stagnation temperature, and mainstream recovery temperature. The adiabatic wall temperature and the adiabatic film cooling effectiveness generally decrease and increase, respectively, with streamwise position, and generally decrease and increase, respectively, as blowing ratio becomes larger.
Evaluation of Elastoplasticity-Dependent Creep Property of Magnesium Alloy With Indentation Method: A Reverse Numerical Algorithm and Experimental Validation
Authors: Fujisawa Shoichi , Yonezu Akio , Noda Masafumi , Xu Baoxing
Published: November 2016

Magnesium (Mg) alloys have been widely used in automotive and aerospace industries due to its merits of exceptional lightweight, super strong specific strength, and high corrosion-resistance, where intermetallic compounds with a small volume are very critical to achieve these excellent performance. This study proposes a reverse analysis that can be employed to extract elastoplasticity-dependent creep property of commercial die-cast Mg alloys and their intermetallic compounds from instrumented indentation with two sharp indenters. First, the creep deformation that obeys the Norton's law (ε˙  = Aσn) is studied, and the parameters of A and n are determined from two indentation experiments conducted with different sharp indenters. Then, a numerical algorithm and dimensional function developed is extended to extract the elastoplasticity of various metallic materials by focusing on the loading stage of indentation experiments. By considering the full loading history with both linear increase and holding stages of loads, we propose a framework of reverse analysis to determine both elastoplasticity and creep properties simultaneously. Parallel indentation experiments on pure magnesium and aluminum and Mg alloys are performed, and the results agree well with the numerical predictions.
An Automated Approach to Nacelle Parameterization Using Intuitive Class Shape Transformation Curves
Authors: Christie Robert , Heidebrecht Alexander , MacManus David
Published: November 2016

A tool to create parametric aerodynamic shapes using intuitive design variables based on class shape transformation (CST) curves is presented. To enable this, a system has been developed which accepts arbitrary constraints and automatically derives the analytical expressions which describe the corresponding class shape transformation curves. Parametric geometry definitions for fan cowl and intake aero-lines were developed using the generalized method. Computational fluid dynamics (CFD) analysis of the fan cowl shows that despite the simple geometry definition, its performance characteristics are close to what would be expected of a finished design. The intake geometry was generated in a similar way and met the typical performance metrics for conventional intakes. This demonstrates the usefulness of the tool to quickly and robustly produce parametric aero-lines with good aerodynamic properties, using relatively simple intuitive design variables.
A Research on Waste-Gated Turbine Performance Under Unsteady Flow Condition
Authors: Deng Q. , Burke R. D. , Zhang Q. , Pohorelsky Ludek
Published: November 2016

Turbochargers are key components of engine air-paths that must be carefully considered during the development process. The combination of fluid, mechanical, and thermal phenomenon make the turbocharger a highly dynamic and nonlinear modeling challenge. The aim of this study is to quantify the dynamic response of the turbocharger system across a frequency spectrum from 0.003 Hz to 500 Hz, i.e., for exhaust gas pulsation in steady state, load steps, and cold start drive cycles, to validate the assumption of quasi-steady assumptions for particular modeling problems. A waste-gated turbine was modeled using the dual orifice approach, a lumped capacitance heat transfer model, and novel, physics-based pneumatic actuator mechanism model. Each submodel has been validated individually against the experimental measurements. The turbine inlet pressure and temperature and the waste-gate actuator pressure were perturbed across the full frequency range both individually and simultaneously in separate numerical investigations. The dynamic responses of turbine housing temperature, turbocharger rotor speed, waste-gate opening, mass flow, and gas temperatures/pressures were all investigated. The mass flow parameter exhibits significant dynamic behavior above 100 Hz, illustrating that the quasi-steady assumption is invalid in this frequency range. The waste-gate actuator system showed quasi-steady behavior below 10 Hz, while the mechanical inertia of the turbine attenuated fluctuations in shaft speed for frequencies between 0.1 and 10 Hz. The thermal inertia of the turbocharger housing meant that housing temperature variations were supressed at frequencies above 0.01 Hz. The results have been used to illustrate the importance of model parameters for three transient simulation scenarios (cold start, load step, and pulsating exhaust flow).
Temperature Distribution in Moving Webs Heated by Radiation Panels: Model Development and Experimental Validation
Authors: Cobos Torres Edison O. , Pagilla Prabhakar R.
Published: November 2016

In this paper, we develop a model to determine the temperature distribution in moving webs due to heating by radiation panels and convection from the web surface. Heating of the transported material is common in many web processes, such as printing, coating, and lamination. Radiation panels provide a simple and noncontact means for web heating. To develop a governing equation for moving web temperature, we treat the web as a moving medium under a heating source which is the radiation panel. We consider both radiation and convection and changes in the convection coefficient in the air film between the web surface and the heating source. Using the temperature governing equation, one can predict the web temperature in the moving web that is transported with different speeds under the heating panels. The model development and analysis are dimensionless; therefore, it can be applied to a variety of web materials and heating panel locations. The model development is motivated by the roll-to-roll (R2R) atomic/molecular layer deposition (ALD/MLD) application, and an experimental platform designed to conduct ALD/MLD is employed to validate the model for different scenarios. Comparative results from experiments and model simulations for varying speeds and different operating conditions are provided to validate the model.
Model Test and Numerical Analysis of a Multi-Pile Offshore Wind Turbine Under Seismic, Wind, Wave, and Current Loads
Authors: Wang Wenhua , Gao Zhen , Li Xin , Moan Torgeir
Published: November 2016

Offshore wind turbines (OWTs) might be subjected to seismic loads with different peak accelerations during operation in the actively seismic regions. The earthquakes might be a potential risk for the OWTs due to its stochastic nature. Earthquake with wind and wave loads could act on OWT at the same time; thus, the structural responses of such OWTs should be analyzed taking into consideration the reasonable load combinations. Based on the hydro-elastic similarity, an integrated model of the combined National Renewable Energy Laboratory (NREL) 5 MW wind turbine and a practical pentapod substructure is designed for testing. The governing equations of motion of the integrated OWT are established. The dynamic tests and numerical analysis of the OWT model are performed under different combinations of seismic, wind, and sea load conditions. The El Centro and American Petroleum Institute (API)-based synthesized seismic waves with different peak ground accelerations (PGAs) are considered in this study. The numerical results are in good agreement with the experimental ones. The coupling effect of the OWT structure under the combined load conditions is demonstrated from the experimental and numerical results. The results indicate that the interaction of earthquake, wind, wave, and current should be taken into account in order to obtain proper structural response, especially with small PGA.
Multilayered Inclusions in Locally Resonant Metamaterials: Two-Dimensional Versus Three-Dimensional Modeling
Authors: Krushynska Anastasiia O. , Miniaci Marco , Kouznetsova Varvara G. , Geers Marc G. D.
Published: November 2016

Locally resonant metamaterials (LRMs) controlling low-frequency waves due to resonant scattering are usually characterized by narrow band gaps (BGs) and a poor wave filtering performance. To remedy this shortcoming, multiresonant metamaterial structures with closely located BGs have been proposed and widely studied. However, the analysis is generally limited to two-dimensional (2D) structures neglecting the finite height of any real resonator. The aim of this paper is the comparison of the wave dispersion for two- and three-dimensional (3D) metamaterial models and evaluation of the applicability ranges of 2D results. Numerical study reveals that dual-resonant structures with cylindrical inclusions possess only a single (compared to two in the 2D case) BG for certain height-to-width ratios. In contrast, the wave dispersion in metamaterials with multiple spherical resonators can be accurately evaluated using a 2D approximation, enabling a significant simplification of resource-consuming 3D models.
Stationary Solution of Duffing Oscillator Driven by Additive and Multiplicative Colored Noise Excitations
Authors: Guo Siu-Siu , Shi Qingxuan
Published: November 2016

A bistable Duffing oscillator subjected to additive and multiplicative Ornstein–Uhlenbeck (OU) colored excitations is examined. It is modeled through a set of four first-order stochastic differential equations by representing the OU excitations as filtered Gaussian white noise excitations. Enlargement in the state-space vector leads to four-dimensional (4D) Fokker–Planck–Kolmogorov (FPK) equation. The exponential-polynomial closure (EPC) method, proposed previously for the case of white noise excitations, is further improved and developed to solve colored noise case, resulting in much more polynomial terms included in the approximate solution. Numerical results show that approximate solutions from the EPC method compare well with the predictions obtained via Monte Carlo simulation (MCS) method. Investigation is also carried out to examine the influence of intensity level on the probability distribution solutions of system responses.
Stability Analysis of Tribosystem Based on the Energy Feature of Friction Vibration
Authors: Liu Ting , Li Guobin , Wei Haijun , Xing Pengfei
Published: November 2016

The tribosystem stability in different wear stages was analyzed by the friction vibration energy feature, which was extracted from the phase-space-matrix of friction vibration attractor with singular value decomposition (SVD). An energy feature parameter K of friction vibration was defined as the norm of the singular value feature vector, and the variation of K in different wear stages was also investigated in this paper. Results show that K becomes larger in the running-in wear stage, friction vibration energy becomes higher and tribosystem stability gets worse; K fluctuates smoothly and steadily in the stable wear stage, friction vibration energy is stable and the tribosystem is dynamically stable; and K increases sharply in the severe wear stage, the friction vibration energy increases dramatically and the tribosystem stability decreases greatly. Therefore, the friction vibration energy can reflect the tribosystem stability in different wear stages with the energy feature parameter K.
Electrochemomechanics of Electrodes in Li-Ion Batteries: A Review
Authors: Xu Rong , Zhao Kejie
Published: November 2016

A Li-ion battery is a system that dynamically couples electrochemistry and mechanics. The electrochemical processes of Li insertion and extraction in the electrodes lead to a wealth of phenomena of mechanics, such as large deformation, plasticity, cavitation, fracture, and fatigue. Likewise, mechanics influences the thermodynamics and kinetics of interfacial reactions, ionic transport, and phase transformation of the electrodes. The emergence of high-capacity batteries particularly enriches the field of electrochemomechanics. This paper reviews recent observations on the intimate coupling between stresses and electrochemical processes, including diffusion-induced stresses, stress-regulated surface charge transfer, interfacial reactions, inhomogeneous growth of lithiated phases, instability of solid-state reaction front (SSRF), as well as lithiation-modulated plasticity and fracture in the electrodes. Most of the coupling effects are at the early stage of study and are to be better understood. We focus on the elaboration of these phenomena using schematic illustration. A deep understanding of the interactions between mechanics and electrochemistry and bridging these interdisciplinary fields can be truly rewarding in the development of resilient high-capacity batteries.
Fracture Response of Girth-Welded Pipeline With Canoe Shape Embedded Crack Subjected to Large Plastic Deformation
Authors: Seng Tjhen Lie , Yao Zhang , Hai Sheng Zhao
Published: November 2016

Long-distance offshore pipelines always suffer large plastic deformation during installation and operation. Accompanied by high internal pressure, potential flaws are found to initiate from the girth welds, and this brings a significant challenge to the structural integrity of the pipelines. The currently used procedures for fracture assessment of pipelines are usually stress based, which are unsuitable for application to cracked pipeline subjected to large plastic deformation. Therefore, the aim of this paper is to investigate the fracture assessment of pipeline subjected to large plastic deformation and identify and understand the critical parameters influencing the fracture responses under actual loading conditions. The evolution of crack tip opening displacement (CTOD) of a pipeline segment with an embedded canoe shape crack located in the middle of the girth weld is investigated under pure bending and biaxial loading through 3D elastic–plastic finite-element simulations. The effects of crack width, crack length, pipeline thickness, material hardening, and internal pressure on fracture response are discussed. Finally, a strain-based failure assessment diagram (FAD) is developed, and comparison between fracture assessment by BS7910:2013 and finite-element simulations concludes that the former produces conservative predictions for deep crack.
Numerical and Experimental Study of Elastic Interaction in Bolted Flange Joints
Authors: Zhu Linbo , Bouzid Abdel-Hakim , Hong Jun
Published: November 2016

Bolted flange joints are widely used to connect pressure vessels and piping equipment together and facilitate their disassembly. Initial tightening of their bolts is a delicate operation because it is extremely difficult to achieve the target load and uniformity due to elastic interaction. The risk of failure due to leakage and fatigue under service loading is consequently increased. This paper presents a study on the effect of elastic interaction that is present during the tightening of bolted flange joints using three-dimensional nonlinear finite-element modeling and experimentation. The nonlinear nonelastic behavior of the gasket is taken into account in the numerical simulation. The scatter in bolt preload produced during the tightening sequence is evaluated. Based on the elastic interaction coefficient method, the initial target tightening load in each bolt for every pass is determined by using the nonlinear finite-element model to obtain a uniform preload after the final tightening pass. The validity of the finite-element analysis (FEA) is supported by experimental tests conducted on a NPS 4 class 900 weld neck bolted flange joints using fiber and flexible graphite gaskets. This study provides guidance and enhances the safety and reliability of bolted flange joints by minimizing bolt load scatter due to elastic interaction.