bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mathematical relationships of patterns of 35 rat haemodynamic parameters for conditions of hypertension resulting from decreased nitric oxide bioavailability
Authors: Kurakova Lucia , Misak Anton , Tomasova Lenka , Cacanyiova Sona , Berenyiova Andrea , Ondriasova Elena , Balis Peter , Grman Marian , Ondrias Karol 
Published: November 2019

New Findings
What is the central question of this study?
Can the cross‐relationship between 35 rat arterial pulse waveform (APW) parameters be described by known mathematical functions and can mathematical parameters be obtained for conditions in a model of hypertension resulting from decreased NO bioavailability?

What is the main finding and its importance?
Mathematical functions and their parameters were obtained that approximate the cross‐relationships of 35 APW parameters to systolic blood pressure and to the augmentation index in conditions of decreased NO bioavailability. The results enable APW parameters to be assigned to decreased NO bioavailability, which may have predictive or diagnostic value.
AbstractInformation obtained from the arterial pulse waveform (APW) using haemodynamic parameters (HPs) is useful for characterization of the cardiovascular system in particular (patho)physiological conditions. Our goal was to find out whether the relationships between rat HPs could be described by simple mathematical functions and to find mathematical parameters for conditions of high blood pressure (BP) resulting from decreased NO bioavailability. The right jugular vein of anaesthetized Wistar rats was cannulated for i.v. administration of Nω‐nitro‐l‐arginine methyl ester (l‐NAME). The left common carotid artery was cannulated to detect the APW. From 10 points on the rat APW we defined 35 HPs (some were known already) and found 595 cross‐relationships between HPs showing unique patterns for particular cardiovascular conditions. Here we show parallel time‐dependent changes of 35 HPs and some of their cross‐relationships in condition of high BP induced by l‐NAME. We found that most of the time‐dependent changes of 35 HPs and their relationships were very well fitted by simple mathematical functions, e.g. a linear function, exponential growth, exponential decay or exponential rise to maximum. The results may enable the mathematical functions to be assigned for decreased NO bioavailability, which may have predictive or diagnostic value for conditions of high BP. Using this approach, it may be possible to find unique cross‐relationship patterns of HPs and mathematical functions between HPs for different cardiovascular (patho)physiological or drug‐modulating conditions. This knowledge can be used in studying the molecular mechanisms of particular (patho)physiological conditions or drug actions and may have predictive or diagnostic value.
Improved Thermodynamic Model for Lean Natural Gas Spark Ignition in a Diesel Engine Using a Triple Wiebe Function
Authors: Liu Jinlong , Dumitrescu Cosmin Emil 
Published: November 2019

Abstract
The use of natural gas (NG) in heavy-duty internal combustion engines can reduce the dependence on petroleum fuels and greenhouse gas emissions. Diesel engines can convert to NG spark ignition (SI) by installing a high-energy ignition system and a gas injector. The diesel combustion chamber affects the flow inside the cylinder, so some existing SI combustion models will not accurately describe the operation of converted diesels. For example, the single Wiebe function has difficulties in correctly describing the mass fraction burn (MFB) throughout the combustion process. This study used experiments from a 2L single-cylinder research engine converted to port fuel injection NG SI and operated with methane at 1300 rpm and equivalence ratio 0.8 (6.2 bars IMEP) to compare the standard Wiebe function with a triple Wiebe function. Results indicated that lean-burn engine operation at an advanced spark timing produced three peaks in the heat release rate, suggesting a multi-stage combustion process. A “best goodness-of-fit” approach determined the values of the key parameters in the zero-dimensional Wiebe function model. The triple Wiebe function described the mass fraction burn and combustion phasing more accurately compared with the single Wiebe function. Moreover, it provided the duration and phasing of each individual burning stage that can then characterize the combustion in such converted diesel engines. This suggests that a multiple Wiebe function combustion model would effectively assist in analyzing such a multi-stage combustion process, which is important for engine optimization and development.
The Science and Technology of Void Fraction Measurements in Multiphase Flow
Authors: Kendoush Abdullah Abbas 
Published: November 2019

Abstract
Void fraction measuring techniques are reviewed with emphasis on applications to multiphase flow. The presentation is divided into two main sections; intrusive where the probe penetrates into the flow field, and non-intrusive where the detection is done remotely. The latter is more preferrable than the former. We subdivided the non-intrusive techniques into into two main categories; nuclear and non-nuclear. In the nuclear section, we discussed the utilization of almost all types of radiations, namely; beta, neutrons, gamma, X-ray, near infrared, in addition to the nuclear magnetic resonance. In the non-nuclear techniques, we presented the following methods; fluorescence, optical sensors, laser, autotransformer winding, ultrasonic, and photgraphy. Some other non nuclear miscellaneous techniques were discussed.
Transient Characteristics of a Centrifugal Pump at Rapid Startup
Authors: Tanaka Teiichi , Tabaru Michiya 
Published: November 2019

Abstract
Experimental and CFD studies were carried out on transient behavior of a centrifugal pump at rapid startup. Relationship between the transient characteristics and a flow field in the centrifugal pump was investigated during transient period of the centrifugal pump from experimental results. A single-stage, volute type centrifugal pump is used for the experiments. The pump is equipped with transparent impeller, casing, suction pipe and discharge pipe for PIV in the future. The test setup is a closed-loop and consists of a suction tank, a test pump, an ultrasonic flow meter and a flow control valve. Instantaneous pressure and flow rate were measured at suction and discharge ports with rotational speed during the transient period. The pump suction and delivery pressures were measured using strain gauge type pressure transducers. Unsteady flow rate was calculated from pressure difference between two pressure measurement points in straight pipe of the pump suction lines using the difference of inertia force. The three-dimensional incompressible flow calculation of the test pump is performed using ANSYS® CFX 17.1. The CFD domain is consisted of a pump suction pipe, a pump casing, an impeller and a pump delivery pipe. For all computations, a block structure mesh of around 1,550,000 elements has been used. The mesh is created with the mesh generator ANSYS® ICEM CFD Ver.17.1. Frozen Rotor Method is used for the steady state calculation, and Transient Rotor Method is used for the unsteady calculation. The standard SST model is used for turbulence modelling. Boundary conditions of the pump inlet and outlet are used the time history of total head and mass flow rate obtained from experiment result, respectively. The variation of pump operating point, torque and axial thrust force during transient period were related to the time-dependent flow field, which was investigated using CFD, in the pump. As results of the present study, it was shown that the pump operating point in experiment were larger than quasi-steady one at early transient stage, and then the pump operating point reaches to quasi-steady one. CFD results indicated similar tendency to experimental results on the variation of the pump operating point. Moreover, variation of the torque and axial thrust force during transient period also indicated deviation from each quasi-steady change. From the experimental and CFD results, the deviation of pump operating point, torque and axial thrust force from the quasi-steady change during pump startup period occurs at a large flow rate acceleration. The reason is thought to be due to that the flow field at large flow rate change cannot develop compared with that at the quasi-steady change.
Computational Fluid Dynamics Modelling of a Load Sensing Proportional Valve
Authors: Corvaglia Alessandro , Altare Giorgio , Finesso Roberto , Rundo Massimo 
Published: November 2019

Abstract
In this paper, two 3D CFD models of a load sensing proportional valve are contrasted. The models were developed with two different software, Simerics PumpLinx® and ANSYS Fluent®. In both cases the mesh was dynamically modified based on the fluid forces acting on the local compensator. In the former, a specific template for valves was used, in the latter a user-defined function was implemented. The models were validated in terms of flow rate and pressure drop for different positions of the main spool by means of specific tests. Two configurations were tested: with the local compensator blocked and free to regulate. The study has brought to evidence the reliability of the CFD models in evaluating the steady-state characteristics of valves with complex geometry.
Numerical Simulation of Unsteady Moist-Air Flows Through Whole-Annulus Rotor Blade Rows in Transonic Compressor
Authors: Moriguchi Shota , Endo Takuro , Miyazawa Hironori , Furusawa Takashi , Yamamoto Satoru 
Published: November 2019

Abstract
In this study, we numerically investigated moist-air flow through the transonic compressor rotors of NASA Rotor 37, assuming whole-annulus rotor blade rows and non-uniform inlet wetness. This is an extension of our previous study, which assumed only a single passage and uniform inlet wetness. The amount of water droplets streaming into the compressor was changed in circumferentially non-uniform inlet condition. Numerical results indicated that non-uniform inlet wetness induced non-uniform temperature in the passages due to absorption of latent heat by droplet evaporation. Moreover, shock locations varied, depending on the local amount of wetness. Furthermore, turning angles of the flow and torque on the rotor blades were influenced by the wetness. Therefore, unsteady forces on the rotor blades were resultantly obtained by considering non-uniform inlet wetness conditions.
Theoretical and Numerical Analysis of the Pressure Distribution and Discharge Velocity in Flows Under Inclined Sluice Gates
Authors: Epple Philipp , Steppert Michael , Malcherek Andreas , Fritsche Manuel 
Published: November 2019

Abstract
The flow under sluice gates is nowadays frequently still determined by empirical approaches, based on the Bernoulli equation and a specific discharge coefficient which depends on the geometry of the sluice gate. This discharge coefficient is determined either from potential theory approaches or from a variety of experimental series. Based on Malcherek’s new momentum balance theory approach, the flow under inclined sluice gates can be described now on a physical approach. While the pressure distribution of the vertical sluice gate, which was investigated by the authors in previous works, results in a horizontal acting force only, the pressure distribution of the inclined sluice gate brings an additional force component acting in the vertical direction. The magnitude and the sign of the force in the vertical direction depends on the sign and the value of the angle of inclination. With the commercial CFD solver Star-CCM+ from Siemens PLM, the flow under inclined sluice gates was investigated in detail, to be compared with Malcherek’s momentum balance theory. For this basic investigation, boundary layer effects and 3D effects were first neglected. For various angles of inclination and water levels the pressure distribution on the ground under the sluice gate and on the surface of the sluice gate itself, were evaluated and mathematical functions were introduced to describe the pressure distributions. These results were compared with the results from the vertical sluice gate. Also the discharge velocity and the volumetric flow rate were analyzed and compared with the Malcherek’s new momentum balance theory for inclined sluice gates.
Experimental Investigation on Silver-Graphene Hybrid Nanofluid Droplet Evaporation and Wetting Characteristics of its Nanostructured Droplet Residue
Authors: Siddiqui Farooq R. , Tso Edwin C. Y. , Fu Sau C. , Chao Christopher Y. H. , Qiu Huihe 
Published: November 2019

Abstract
Droplet evaporation is a complex phase change process with a wide range of cooling applications, such as spray cooling and dropwise hotspot cooling in microelectronics, to name a few. The hybrid nanofluid droplet evaporation and its residue effects on evaporation of the subsequent hybrid nanofluid droplet is investigated in this research. Silver-graphene (Ag-GNP) hybrid nanofluid exhibiting synergistic thermal properties is investigated and prepared by dispersing silver nanoparticles along with graphene nanoplatelets in water at 0.1% volume fraction and with different mixing ratios, followed by ultrasonication. The evaporation rate and wetting characteristics of a 3 μl volume of Ag-GNP hybrid nanofluid droplet on a copper surface were studied using an optical tensiometer. Once dried, the nanoporous structure of the residue surface was examined using a scanning electron microscope, while the surface roughness was measured using an optical profiler. Experiments were continued to further investigate the evaporation rate and wetting effects of the subsequent Ag-GNP hybrid nanofluid droplet over the residue surface. The results showed improved wetting characteristics, with 88% reduction in initial static contact angle and 163–196% enhancement in evaporation rate of the subsequent Ag-GNP hybrid nanofluid droplets over the residue surfaces as compared to the copper surface.
Phase Retrieval Holography for Particle Measurement With GPU Acceleration
Authors: Tanaka Yohsuke , Matsushi Hiroki , Murata Shigeru 
Published: November 2019

Abstract
We introduce a graphics processing unit (GPU) acceleration to reconstructing holograms of phase retrieval holography for a drastic reduction of the execution time. We conducted GPU acceleration using the FFT library CUFFT on the GPU chip (GEFORCE GTX 1050, GDDR5 2GB, NVIDIA). We also used Intel Xeon CPU (E5-2690, 2.90GHz, Intel), the memory of 24 GB, and the operating system of Ubuntu 16.04 to compare GPU and CPU. Reconstructed volumes changed from 2562 × 128 voxels to 20482 × 1024 voxel to compare execution times. The ratio of the time of GPU to that of CPUs is constantly higher than 100 times except for small volume. We also demonstrated that GPU acceleration decreased the time by observing falling particles, recorded in 40 frames, from particle feeder. As a result, it is found that the execution time is reduced from 13 hours to 30 minutes.
Modal Analysis of a Utility Bicycle From the Perspective of Riding Comfort
Authors: Doria Alberto , Marconi Edoardo , Cialoni Pierluca 
Published: November 2019

Abstract
The correlation between the modal properties and the comfort characteristics of a utility, step-through frame bicycle are investigated. In-plane modal testing of the vehicle is carried out both without and with the rider, and the major differences between the results obtained with the two conditions are highlighted. In order to have an insight into the contribution of the various bicycle components to the transmission of vibrations, the frequency response functions (FRFs) between the main interface points in the vehicle structure are measured and studied. Finally, the modal characteristics are compared with road tests data, emphasizing the relationship between the in-plane vibration modes and the main peaks in the acceleration power spectral densities (PSDs) measured on the road.
Rapid Investment Casting: Design and Manufacturing Technologies
Authors: Richard Christopher T. , Kwok Tsz-Ho 
Published: November 2019

Abstract
With the emergence of new metal AM (additive manufacturing) methods, rapid IC (investment casting), a variation of conventional investment casting has been a popular topic of research in the fields of: aerospace, dentistry and biomedical engineering. RIC (Rapid investment casting) takes advantage of the additive nature of 3D printing for pattern making which allows for more complex castings than traditional investment casting. RIC is a manufacturing process that combines the casting knowledge accumulated over five thousand years with relatively novel AM knowledge. The result is a process that can compete with newer metal AM methods with the added benefits of excellent surface finish, fatigue strength and the ability to create parts from almost any metal or metal alloy. This article will focus on research advancements in investment casting, AM and all the topics that are closely related to optimizing these two processes. Beyond that, aerospace, dentistry and biomedical engineering advancements using investment casting will be reviewed.
On the Unified Design of Accelerated Gradient Descent
Authors: Chen Yuquan , Wei Yiheng , Wang Yong , Chen YangQuan 
Published: November 2019

Abstract
Nowadays, different kinds of problems such as modeling, optimal control, and machine learning can be formulated as an optimization problem. Gradient descent is the most popular method to solve such problem and many accelerated gradient descents have been designed to improve the performance. In this paper, we will analyze the basic gradient descent, momentum gradient descent, and Nesterov accelerated gradient descent from the system perspective and it is found that all of them can be formulated as a feedback control problem for tracking an extreme point. On this basis, a unified gradient descent design procedure is given, where a high order transfer function is considered. Furthermore, as an extension, both a fractional integrator and a general fractional transfer function are considered, which resulting in the fractional gradient descent. Due to the infinite-dimensional property of fractional order systems, numerical inverse Laplace transform and Matlab command stmcb() are used to realize a finite-order implementation for the fractional gradient descent. Besides the simplified design procedure, it is found that the convergence rate of fractional gradient descent is more robust to the step size by simulating results.
Exploring Situational Factors and Attitudes Affecting Sustainable Electric Kettle Usage
Authors: Engelking Kimberly Elisabeth , Irie Kanako , Thorup Rasmus Velling , Ramanujan Devarajan 
Published: November 2019

Abstract
This paper explores situational factors and attitudes affecting sustainable electric kettle usage. We conducted a two-week long field study with five residents in Denmark who self-reported their electric kettle usage data, purpose of usage, and situations of usage, over the study period. A follow-up interview was also conducted after the field study to explore reasons behind the observed behaviors. Results show, the amount of excess water heated significantly varied by usage purpose as well as the time sensitivity of the usage purpose. There was no observable effect of the minimum fill level marker on the amount of excess water heated. Participants’ considerations for purchasing a specific kettle and their usage behaviors were not influenced by sustainability-related concerns. We identified four important factors that influenced the amount of excess water heated and participants’ decision to retain or dispose it. They included, (1) uncertainty in the need for hot water in the near future, (2) flexibility in the needed volume for a usage purpose, (3) forgetting to use heated water, and (4) concerns about limescale build up.
Environmental and Economic Evaluation of the Sheet Metal Stamping Process Using Alternative Lubricants
Authors: Landi Daniele , Germani Michele , Mandolini Marco , Marconi Marco , Favi Claudio 
Published: November 2019

Abstract
Sheet metal forming of tribologically difficult materials (e.g. stainless steel) or forming in tribologically difficult conditions (e.g. ironing, punching, deep drawing) require the use of environmentally hazardous lubricants, such as chlorinated paraffin oils in order to avoid galling. The present paper describes an environmental and economic evaluation of two alternative sheet metal stamping processes. The forming of a sheet metal component for boiler burners has been taken as case study for the analyses. In particular, two different lubricants (standard mineral versus polymer matrix-based lubricant) have been tested and compared. However, the differences among the two processes involves not only the lubrication phase, but also the electric energy consumption during the stamping and degreasing, as well as the typology of solvent (perchloroethylene versus water). Results obtained with the economic analysis show that the use of the alternative lubricant leads to a 16% reduction of the total manufacturing cost, mainly due to the optimization of the degreasing. Concerning environmental results, instead, no relevant differences can be observed for almost all the considered impact categories (ReCiPe midpoint and endpoint), since the optimized phases are not the most critical ones.
Topology Design With Conditional Generative Adversarial Networks
Authors: Sharpe Conner , Seepersad Carolyn Conner 
Published: November 2019

Abstract
Deep convolutional neural networks have gained significant traction as effective approaches for developing detailed but compact representations of complex structured data. Generative networks in particular have become popular for their ability to mimic data distributions and allow further exploration of them. This attribute can be utilized in engineering design domains, in which the data structures of finite element meshes for analyzing potential designs are well suited to the deep convolutional network approaches that are being developed at a rapid pace in the field of image processing. This paper explores the use of conditional generative adversarial networks (cGANs) as a means of generating a compact latent representation of structures resulting from classical topology optimization techniques. The constraints and contextual factors of a design problem, such as mass fraction, material type, and load location, can then be specified as input conditions to generate potential topologies in a directed fashion. The trained network can be used to aid concept generation, such that engineers can explore a variety of designs relevant to the problem at hand with ease. The latent variables of the generator can also be used as design parameters, and the low dimensionality enables tractable computational design without analytical sensitivities. This paper demonstrates these capabilities and discusses avenues for further developments that would enable the engineering design community to further leverage generative machine learning techniques to their full potential.