bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of passenger flow characteristics and their relationship with surrounding urban functional landscape pattern
Authors: Liu Yaolin , Tang Mingyang , Wu Zihao , Tu Zhide , An Zihao , Wang Nannan , Li Ying 
Published: July 2020

AbstractThe passenger flow characteristics of rail transit stations and their relationship with surrounding urban space play an important role in urban planning and transit‐oriented development policies. However, passenger flow data are high‐dimensional and complex, and corresponding characteristics are difficult to extract. Moreover, the integration of natural, social and economic factors in urban space may satisfactorily explain passenger flow characteristics. In this study, we clustered stations with passenger flow by using a dynamic time warping (DTW) distance‐based affinity propagation (AP) algorithm. We introduced the urban functional landscape to reveal the urban space surrounding the station by landscape metrics. Then, we explored the relationship between passenger flow characteristics and urban functional landscape pattern. The DTW distance‐based AP algorithm method identified passenger flow characteristics under total, inbound and outbound conditions, with cluster numbers of 3, 5 and 5, respectively. With the distance from the station, the proportion of natural landscape increased (from 26.11 to 36.62%), whereas that of socioeconomic landscape decreased (from 59.87 to 51.57%). The multivariate regression analysis indicated that types of urban functional landscape had significant influence on the passenger flow characteristics in different accessible areas of the station. These findings highlighted the effect of urban functional landscape pattern on passenger flow.
UDP‐Api/UDP‐Xyl synthases affect plant development by controlling the content of UDP‐Api to regulate the RG‐II‐borate complex
Authors: Zhao Xianhai , Ebert Berit , Zhang Baocai , Liu Huabin , Zhang Yutao , Zeng Wei , Rautengarten Carsten , Li Huiling , Chen Xiaoyang , Bacic Antony , Wang Guodong , Men Shuzhen , Zhou Yihua , Heazlewood Joshua L. , Wu Ai‐Min 
Published: July 2020

SUMMARYRhamnogalacturonan‐II (RG‐II) is structurally the most complex glycan in higher plants, containing 13 different sugars and 21 distinct glycosidic linkages. Two monomeric RG‐II molecules can form an RG‐II‐borate diester dimer through the two apiosyl (Api) residues of side chain A to regulate cross‐linking of pectin in the cell wall. But the relationship of Api biosynthesis and RG‐II dimer is still unclear. In this study we investigated the two homologous UDP‐D‐apiose/UDP‐D‐xylose synthases (AXSs) in Arabidopsis thaliana that synthesize UDP‐D‐apiose (UDP‐Api). Both AXSs are ubiquitously expressed, while AXS2 has higher overall expression than AXS1 in the tissues analyzed. The homozygous axs double mutant is lethal, while heterozygous axs1/+ axs2 and axs1 axs2/+ mutants display intermediate phenotypes. The axs1/+ axs2 mutant plants are unable to set seed and die. By contrast, the axs1 axs2/+ mutant plants exhibit loss of shoot and root apical dominance. UDP‐Api content in axs1 axs2/+ mutants is decreased by 83%. The cell wall of axs1 axs2/+ mutant plants is thicker and contains less RG‐II‐borate complex than wild‐type Col‐0 plants. Taken together, these results provide direct evidence of the importance of AXSs for UDP‐Api and RG‐II‐borate complex formation in plant growth and development.
ZmDREB2A regulates ZmGH3.2 and ZmRAFS, shifting metabolism towards seed aging tolerance over seedling growth
Authors: Han Qinghui , Chen Kelu , Yan Dong , Hao Guanglong , Qi Junlong , Wang Chunmei , Dirk Lynnette M.A. , Bruce Downie A. , Gong Jianhua , Wang Jianhua , Zhao Tianyong 
Published: July 2020

SummarySeed aging tolerance and rapid seedling growth are important agronomic traits for crop production; however, how these traits are controlled at the molecular level remains largely unknown. The unaged seeds of two independent maize DEHYDRATION‐RESPONSIVE ELEMENT‐BINDING2A mutant (zmdreb2a) lines, with decreased expression of GRETCHEN HAGEN3.2 (ZmGH3.2, encoding indole‐3‐acetic acid [IAA] deactivating enzyme), and increased IAA in their embryo, produced longer seedling shoots and roots, than the null segregant (NS) controls. However, the zmdreb2a seeds, with decreased expression of RAFFINOSE SYNTHASE (ZmRAFS) and less raffinose in their embryo, exhibit decreased seed aging tolerance, than the NS controls. Overexpression of ZmDREB2A in maize protoplasts increased the expression of ZmGH3.2, ZmRAFS genes and that of a Rennila LUCIFERASE reporter (Rluc) gene, which was controlled by either the ZmGH3.2‐ or ZmRAFS‐promoter. Electrophoretic mobility shift assays and chromatin immunoprecipitation assay quantitative polymerase chain reaction showed that ZmDREB2A directly binds to the DRE motif of the promoters of both ZmGH3.2 and ZmRAFS. Exogenous supplementation of IAA to the unaged, germinating NS seeds increased subsequent seedling growth making them similar to the zmdreb2a seedlings from unaged seeds. These findings provide evidence that ZmDREB2A regulates the longevity of maize seed by stimulating the production of raffinose while simultaneously acting to limit auxin‐mediated cell expansion.
MRI utricle diameter asymmetry is significantly greater in dogs with idiopathic vestibular syndrome compared with unaffected dogs
Authors: Won Sungjun , Yoon Junghee 
Published: July 2020

AbstractIdiopathic vestibular syndrome (IVS) is the most common cause of acute unilateral peripheral vestibular dysfunction in older dogs. The purpose of this retrospective, cross‐sectional study was to characterize morphological changes in the utricle of dogs affected by IVS, using MRI. To evaluate differences between affected and unaffected utricles, the ratio of the largest to the smallest utricle diameter was obtained, as measured on transverse T2‐weighted images, and defined as the utricle asymmetricity ratio (UAR). Out of 137 patients diagnosed with IVS after excluding other vestibular diseases by MRI, 101 were eligible for inclusion. Additionally, 31 older dogs with no signs of vestibular disorders or other intracranial diseases were included as a control group. The disease group was divided into two subgroups in which the direction of head tilt and nystagmus symptoms versus the decreased utricle diameters were consistent or inconsistent. The medians of UARs of the IVS and control groups were 0.83 (range 0.37‐1.00) and 0.98 (0.70‐1.00), respectively. The medians of the UARs of the consistent and inconsistent IVS subgroups were 0.82 (0.37‐0.99) and 0.90 (0.74‐1.00), respectively. The UAR of the IVS group was significantly decreased than that of the control group and UAR of the consistent sub‐group was significantly decreased than that of the inconsistent sub‐group (P < .01). In conclusion, significant asymmetry of utricle diameter was identified in dogs with IVS versus unaffected dogs. We propose that canine IVS may possibly be correlated with structural atrophy of the vestibular system.
Access to Empirical Formulations of Combustion Efficiency for Gas Turbine Combustors With Improved Generalization Ability
Authors: Ma Zhuang , Ji Tingwei , Cui Tao , Zheng Yao 
Published: July 2020

Abstract
Correlating combustion performance parameters to the main operating variables of combustors with mathematical expressions contributes to reducing the number of experiments and simplifying the design procedure of gas turbines. The application of empirical formulations meets the requirement with finite precision. The present study aims at adopting symbolic regression method to establish empirical formulations to correlate combustion efficiency with the main operating variables of gas turbine combustors. Differing from ordinary data modeling methods that search model parameters only with model structures fixed, symbolic regression method can search the structures and parameters of mathematical models simultaneously. In this article, attempts to correlate the experimental data of Combustor I using the mechanism model of burning velocity model, neural network, polynomial regression, and symbolic regression are shown sequentially. Burning velocity model has not satisfactory accuracy by comparing the predictions with the experimental data which means its lower generalization ability. Comparatively, the predictions of the empirical formulation obtained by the present symbolic regression method are in good agreement with the experimental data and also excel those of neural network and polynomial regression in generalization ability. Another two formulations are obtained by symbolic regression using the experimental data of Combustor II and III, and the different model structures of the two formulations indicate that there is still room for improvement in the present method.
A Numerical Investigation of Air/Mist Cooling Through a Conjugate, Rotating 3D Gas Turbine Blade With Internal, External, and Tip Cooling
Authors: Abdelmaksoud Ramy , Wang Ting 
Published: July 2020

Abstract
This paper describes a numerical investigation to study the effect of injecting mist (tiny water droplets) into the cooling air used to cool down rotating gas turbine blades. In this study, the conjugate heat transfer method is used which consists of the simulation of the air/mist fluid flow inside and outside the blades as well as the heat conduction through the blade body. The complete 3D blade with internal cooling passages and external film cooling holes on the surface and blade tip is simulated in a rotating, periodic sector of the blade. The discrete phase model (DPM) is used to simulate and track the evaporation and movement of the tiny water droplets. The rotation effect of the turbine blade is included in the computational fluid dynamics (CFD) simulation by using the moving reference frame method. The effects of different parameters such as the mist/air ratio (10–20%) and the mist droplets size (20–40 µm) on mist cooling enhancement are investigated. The results show that the mist cooling enhancements are about 10–25% on the outer surface of the blade and reach 50% in some locations inside the blade on the internal cooling passages walls. Most of the liquid droplets completely evaporate inside the internal cooling passages; only a limited amount of mist is able to escape from the film cooling holes to enhance the blade outer surface and blade tip cooling. The effect of 10% mist on enhanced cooling can be converted to an equivalent of a 30% reduction in cooling air flow.
An Experimentally Validated Model of a Cross-Flow Sub-Wet Bulb Evaporative Chiller
Authors: Yang Yahui , Narayanan Vinod , Pistochini Theresa , Ross Derrick 
Published: July 2020

Abstract
A simplified model to predict the performance of a novel sub-wet bulb evaporative chiller (SWEC) for producing chilled water is presented. The SWEC design uses a daisy-chained arrangement of cross-flow heat exchangers (HXs) with evaporative media located in between the heat exchangers to chill water below the outdoor wet bulb temperature (WB) in either a one-pass or two-pass arrangement. Sub-models, based on the effectiveness-number of transfer units (ɛ-NTU) method, for the heat exchanger and evaporative media are coupled together to form the SWEC model. The model is validated using field data from a SWEC that is designed with a single water pass. The model results are observed to match the SWEC experimental data within a mean average error (MAE) of 0.74% in supply chilled water temperature and 5.6% in chiller capacity over a range of outdoor air dry bulb and wet bulb temperatures, inlet water temperatures, and water flowrates. The validated model is then used in a parametric study of geometrical and thermofluidic variables. The model is also used to predict the performance of the SWEC in a typical hot and dry weather over a summer week.
Droplet Coalescence in Liquid/Liquid Separation
Authors: E. Weiwei , Pope Kevin , Duan Xili 
Published: July 2020

Abstract
In this paper, a new correlation is developed to predict liquid/liquid separation dynamics with a focus on a water/oil mixture. The correlation employs a force balance on the droplets to predict the rising velocity of the oil phase. The effect of droplet coalescence on the droplet's rising velocity is investigated, and the new correlation predicts the coalescence rate based on the oil/water volume fraction, as well as the initial droplet diameter. To develop the correlation for droplet coalescence, a series of new numerical simulations of a batch oil/water separation process were conducted. An equivalent experiment was conducted, the results of which agree well with the numerical predictions (relative error of 13.39%). The new correlation can predict the rate of separation with a relative error of 6.35% compared to numerical predictions.
Imperfect Bifurcation and Chaos of Slightly Curved Carbon Nanotube Conveying Hot Pressurized Fluid Resting on Foundations
Authors: Oyelade Akintoye O. , Oyediran Ayo A. 
Published: July 2020

AbstractUnintended slight curvature of a straight pipe and temperature variation in a pipe has been found to create uncertainties in tubes and pipes. Fluttering, divergence, and chaotic instabilities of slightly curved carbon nanotubes (SCCNT) conveying hot pressurized fluid are investigated in this paper. The SCCNT is modeled on the basis of large deformation strains. Their gradients are included in the strain energy expression and the velocity and its gradients in the kinetic energy derivation. In modeling the size effects, both the static and kinetic length scales in the energy equations were considered. Governing equation is derived using Lagrangian approach. The effects of geometric imperfection (which leads to cusp bifurcation), small length scale, and kinetic material length parameter on the static and dynamic instability characteristics of the pipes are studied. Analysis is performed using the eigenfunction expansion method. It is found that the material length scale parameter increase tends to shift instability to the lower fluid velocity while the kinematic material length parameter increase does not change the buckling point but lowers the frequency. In the nonlinear dynamic case, both the parameters lead to chaos of the nanotube beyond the critical fluid velocity. The thermal loading changes the sudden supercritical pitchfork bifurcation to cusp bifurcation. The increasing linear and nonlinear foundation stiffness leads the system to chaotic features after the critical point.
Investigation on the Energy Exchange Characteristics of the Regenerative Flow Pump in an Automobile Fuel System
Authors: Li Qian-qian , Zhao Guo-shou , Wu Cheng-shuo , Wu Peng , Wu Da-zhuan , Guo Chun-lin 
Published: July 2020

AbstractThe flow inside the regenerative flow pump (RFP) is quite complex. This study investigated four pump models with various geometrical dimensions to explore the energy exchange characteristics. A computational fluids dynamics (CFD) simulation and the experiment were carried out. The results illustrate that the pressure growth mode in the impeller is consistent with the channels, which confirms the circulation flow existing in the pump. Furthermore, it is found that the circulation flow that features with longitudinal vortexes can be evaluated quantitatively by combining the analyses of the dimensionless axial distance, circulation number and entropy production. A smaller axial distance indicates that more flow is involved in the circulation and the intensity of the longitudinal vortex is enhanced; a large circulation number accompanied by a small dissipation loss could result in a satisfactory exchange flow. Therefore, the largest circulation number, least amount of dissipation, and shortest distance lead to the highest head and efficiency in the model with V-shaped blades and an increased impeller height. This work establishes a deeper understanding of the energy exchange mechanism and could serve as a reference for the geometrical design and performance reinforcement of RFP.
Relationship Between Flow Instability and Performance of a Centrifugal Pump With a Volute
Authors: Shim Hyeon-Seok , Kim Kwang-Yong 
Published: July 2020

Abstract
Flow instability and its correlations with performance characteristics were investigated for a centrifugal pump with a volute. Unsteady three-dimensional Reynolds-averaged Navier–Stokes analysis was performed to analyze the flow and performance characteristics using the shear stress transport (SST) turbulence model. The grid dependence and temporal resolution were tested to evaluate the numerical uncertainties, and the numerical solutions were validated using experimental data. The total-to-static head coefficient, the impeller's total-to-static head coefficient, and the volute static pressure recovery coefficient were selected as performance parameters. To identify the flow instability, pressure fluctuations were monitored upstream of the impeller, at the volute inlet, and on the shroud wall of the impeller. Three different types of flow instability were detected in partial-load conditions: inside the volute, upstream of the impeller, and at the interface between the impeller and volute. The time-dependent flow structures were investigated to obtain insight into the onset of the flow instability. The correlation of the onset of the flow instability with the performance curves was discussed.
Computational Study of the Effect of Homogeneous and Heterogeneous Bubbly Flows on Bulk Gas–Liquid Heat Transfer
Authors: Panicker Nithin S. , Passalacqua Alberto , Fox Rodney O. 
Published: July 2020

AbstractA numerical investigation is performed on buoyancy-driven homogeneous and heterogeneous bubbly flows to compare the bulk gas–liquid heat transfer effectiveness for Prandtl (Pr) numbers 0.2–20 and void fractions 〈αg〉 0.3–0.5. For this purpose, transient two-fluid model simulations of bubbles rising in a stagnant pool of liquid are conducted in a rectangular box by applying periodic boundary conditions to all the sides. The temperature difference (ΔT) between gas and liquid phase is averaged over the rectangular box and monitored with respect to time, the heat transfer rate is studied based on the time at which the ΔT tends to zero. The results of numerical study show that at low Pr numbers, faster decay of ΔT is observed for homogeneous flow of bubbles indicating higher heat transfer rate in comparison with the heterogeneous flow of bubbles for the same void fraction. On the contrary, for high Pr numbers, higher heat transfer rate is observed in heterogeneous flow compared to the homogeneous. The comparison of heat transfer behavior between different void fractions for heterogeneous flow show that, for low Pr numbers higher heat transfer rate is achieved for void fraction 0.4 in comparison with void fraction 0.5. And for high Pr numbers, higher heat transfer is observed for void fraction 0.5 in comparison with void fraction 0.4.
Experimental and Numerical Investigation on the Influence of Thermally Induced Stress Gradients on Fatigue Life of the Nickel-Base Alloy Mar-M247
Authors: Thiele Marcus , Eckmann Stefan , Huang Min , Gampe Uwe , Fischer Kathrin A. , Schlesinger Michael 
Published: July 2020

Abstract
Today's and future parameters of stationary gas turbines and aircraft engines require intensive and highly efficient cooling of hot gas path components. High temperature and thermally induced stress gradients with impact on fatigue life are the consequence. Thermally induced stress gradients differ from geometrically induced stress gradients with respect to stress mechanics by the independence from external loads and material mechanics by the influence of temperature on material properties and strength. Regarding the contribution and evaluation on damage, the latter characteristic feature in turbomachinery is currently not fully understood. Therefore, a test facility has been designed, setup, and reported in GTP-18-1482 for the investigation of the influence of stationary temperature, and thus thermally induced stress gradients, on the damage evolution of cooled high-temperature components. To achieve high temperature and thermally induced stress gradients, large heat fluxes are required. A unique radiation heating has been developed allowing very high heat fluxes of q˙ ≥ 1.5 MW/m2 for testing of hollow cylindrical specimens. The conventional cast nickel-base alloy Mar-M247 has been chosen to study the influence of thermally induced stress gradients on fatigue life. The low-cycle fatigue testing of the hollow cylindrical specimens has been conducted both with and without superimposed stationary temperature gradients. In addition, complex low-cycle fatigue (CLCF) tests with symmetric and nonsymmetric loading conditions have been performed to provide the necessary database for the adaptation of a viscoplastic deformation model. To calculate the local stress–strain field and service life of the test specimens, linear elastic and viscoplastic finite element studies have been performed and were assessed by means of a fracture mechanics-based lifetime model. The test results show the considerable influence of the temperature gradient on the low-cycle fatigue life for the investigated material. Both the radial temperature variation over the specimen wall with a hot outer surface and a cooled inner surface as well as the thermally induced stresses are stated to be the main drivers for the change in low-cycle fatigue life. The test results enhance the understanding of fatigue-damage mechanisms under local unsteady conditions and can be used as a basis for improved service life predictions.
Arcuate thrust systems in sandbox experiments: A comparison to the external arcs of the Western Alps
Authors: Lickorish W.H. , Ford M. , Bürgisser J. , Cobbold P.R. 
Published: July 2020

Abstract
In the external Western Alps, two regional structural arcs were generated during Tertiary northwest-directed collision between the Apulian indenter and the European passive margin. These arcs, distinguished by their geographic position and their age, are examined by using a new compilation of structural data and comparing these to the results of sandbox-analogue experiments. The principal Western Alpine arc comprises two orthogonal, synchronous thrust systems. In the late Eocene–early Miocene, major shortening (105 km) was toward the northwest to west-northwest, and minor shortening (11 km) was toward the southwest. Shortening in each branch decreased toward the core of the arc. During the late Miocene and Pliocene, the Jura arc accommodated 35 km of northwest- directed shortening, while 10.5 km of southwest- to south-southwest–directed shortening was accommodated on the Digne thrust system.
Sandbox experiments were used to investigate the role of the motion vector of a rigid rectangular indenter (orthogonal, diagonal, curved, or rotational paths) and the mechanical stratigraphy of the foreland in the evolution of upper-crustal arcuate systems (e.g., presence of a basal easy-slip [silicone] horizon). Comparison of experimental results with the external Alpine arc suggests that the indenter followed a slightly diagonal path with respect to the European margin from the Eocene to the early Miocene and curved counterclockwise by 10°–15° in the middle Miocene. Mechanical stratigraphy experiments support the hypothesis that thick Triassic evaporites played a primary role in the evolution of the Jura arc. The influence of mechanical stratigraphy was most prominent during weak deformation at the external boundaries of the Alpine orogen (Jura fold-and-thrust belt, Digne thrust).