bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Total Flavonoids from Exocarpium Citri Grandis on Air Pollution Particle‐Induced Pulmonary Inflammation and Oxidative Stress in Mice
Authors: Zhu Zhiting , Wu Hao , Su Weiwei , Shi Rui , Li Panlin , Liao Yan , Wang Yonggang , Li Peibo
Published: November 2019

Exocarpium Citri Grandis (ECG) is a famous traditional Chinese medicine, which has been commonly used to alleviate cough and phlegm for more than several hundred years, and total flavonoids are the main effective components of this medicine. This study investigated the effects of total flavonoids from ECG (TFECG) on pulmonary inflammation and oxidative stress induced by PM2.5 in mice. Model mice received an intratracheal instillation of PM2.5 (10 mg/mL) once at day 0. Bronchoalveolar lavage fluid (BALF) was collected after 72 hr to measure the total number of white blood cell (WBC), neutrophils (NEUT), lymphocytes (LYMPH), and monocytes (MONO). The levels of tumor necrosis factor‐α (TNF‐α), interleukin 1β (IL‐1β), interleukin‐6 (IL‐6), and interleukin‐18 (IL‐18) in BALF were quantified by using enzyme‐linked immunosorbent assay kits. Lung tissues were used to determine the contents of total protein (TP), malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), oxidized glutathione (GSSG) and the activities of superoxide dismutase (SOD), lactate dehydrogenase (LDH), Glutathione Peroxidase (GSH‐Px), and inducible nitric oxide synthase (iNOS). We found that TFECG significantly inhibited PM2.5‐stimulated overproduction of TNF‐α, IL‐1β, IL‐6, and IL‐18 and increased the numbers of WBC, NEUT, LYMPH, and MONO in BALF. TFECG observably relieved the PM2.5‐induced increases in the contents of TP, MDA, and NO, and the activities of LDH and iNOS. TFECG also alleviated PM2.5‐induced decreases in the activities of iNOS and GSH‐Px as well as GSH/GSSG ratio. The results indicate that TFECG has anti‐inflammatory and antioxidant activities, which may potentially contribute to the treatment of PM2.5‐induced lung injury.

Practical Application

Exocarpium Citri Grandis (ECG) is rich in flavonoids, which are beneficial to improve anti‐inflammation and antioxidant capacity. We proved that total flavonoids of ECG had a positive therapeutic effect on PM2.5‐induced lung injury, which expands the potential applications of ECG in the dietary supplement industries.
Barcodeleser – ein algorithmischer Ansatz für okkludierende kutane Vaskulopathien? Teil 2: Vaskulopathien mittelgroßer Gefäße
Authors: Ratzinger Gudrun , Zelger Bettina G. , Zelger Bernhard W.
Published: November 2019

Ziele

Die Klassifikation okkludierender Vaskulopathien (außer Vaskulitis [1]) kann einige Schwierigkeiten bereiten. Erstens kann ihre Einteilung unterschiedlichen Prinzipien folgen, wie klinisch‐pathologischen Befunden, Ätiologie oder Pathomechanismus. Zweitens unterscheiden Autoren zuweilen nicht zwischen Vaskulitis und okkludierenden Vaskulopathien. Drittens handelt es sich bei okkludierenden Vaskulopathien um systemische Erkrankungen. Aufgrund organspezifischer Besonderheiten sind morphologische Befunde schwer zu vergleichen. Zudem können geringfügige Veränderungen zwar auf der Haut erkennbar sein, in anderen Organen jedoch verborgen bleiben. Unser Ziel war es, die Haut und die Subkutis als Modell und die klinisch‐pathologische Korrelation als Grundlage für die Klassifikation zu verwenden.

Methoden und Ergebnisse

Im ersten Schritt differenzieren wir zwischen okkludierenden Vaskulopathien kleiner und mittelgroßer Gefäße in der Haut. Dabei konzentrieren wir uns im vorliegenden Teil auf die okkludierenden Vaskulopathien mittelgroßer Gefäße. Im zweiten Schritt differenzieren wir zwischen den Subtypen der Gefäße. Im letzten Schritt differenzieren wir nach dem Zeitpunkt des Koagulations‐/Reorganisationsprozesses sowie nach den beteiligten Entzündungszellen und Stromamerkmalen. Durch die Anwendung des gleichen Verfahrens bei den verschiedenen Entitäten und die Visualisierung der Befunde über Barcodes können die Ähnlichkeiten und Unterschiede besser veranschaulicht werden, sowohl klinisch als auch histopathologisch.

Schlussfolgerungen

Okkludierende Vaskulopathien sind häufig keine eigenständigen Entitäten, sondern Reaktionsmuster und Epiphänomene. Ihre Abgrenzung von den Vaskulitiden ist aufgrund der Unterschiede bei Pathogenese, therapeutischem Vorgehen und Prognose von entscheidender Bedeutung.
Parents in Control: Parental perceptions of problem behaviors before and after attending an ADHD‐specific parent‐training program
Authors: Foubister Louise , Rennie Fiona , Williams Justin
Published: November 2019

Problem

There is scant evidence to support the efficacy of attention deficit hyperactivity disorder (ADHD)‐specific parent‐training programs in the treatment of preadolescent children with ADHD. This study explores the effectiveness of the Parents in Control (PINC) parent‐training program, designed specifically for children with ADHD.

Methods

In this pragmatic uncontrolled pre‐poststudy parents of preadolescent children with a diagnosis of ADHD were invited to attend the 6‐week PINC course. Fifty‐seven parent‐report pre/postprogram questionnaires were completed.

Findings

Parental ratings of the intensity and frequency of problem behaviors after completing PINC showed a significant reduction (p < .001) with a moderate effect size (0.6–0.7).

Conclusions

Our findings demonstrate the efficacy of PINC in reducing the parental perception of problem behaviors and support a need for further rigorous randomised controlled trial (RCT) evaluation of this ADHD‐specific intervention.
Proteomics‐based screening of the target proteins associated with antidepressant‐like effect and mechanism of Saikosaponin A
Authors: Guo Juanjuan , Zhang Feng , Gao Jifang , Guan Xinyuan , Liu Beiyun , Wang Xiaoge , Qin Zhaoyu , Tang Kuanxiao , Liu Shilian
Published: November 2019

Depression is a commonly occurring neuropsychiatric disease with an increasing incidence rate. Saikosaponin A (SA), a major bioactive component extracted from Radix Bupleuri, possesses anti‐malignant cell proliferation, anti‐inflammation, anti‐oxidation and liver protective effects. However, few studies have investigated SA’s antidepressant effects and pharmacological mechanisms of action. Our study aimed to explore the anti‐depression effect of SA and screen the target proteins regulated by SA in a rat model of chronic unpredictable mild stress (CUMS)‐induced depression. Results showed that 8‐week CUMS combined with separation could successfully produce depressive‐like behaviours and cause a decrease of dopamine (DA) in rat hippocampus, and 4‐week administration of SA could relieve CUMS rats’ depressive symptoms and up‐regulated DA content. There were 15 kinds of significant differentially expressed proteins that were detected not only between the control and CUMS groups, but also between the CUMS and SA treatment groups. Proline‐rich transmembrane protein 2 (PRRT2) was down‐regulated by CUMS while up‐regulated by SA. These findings reveal that SA may exert antidepressant effects by up‐regulating the expression level of PRRT2 and increasing DA content in hippocampus. The identification of these 15 differentially expressed proteins, including PRRT2, provides further insight into the treatment mechanism of SA for depression.
Development and quality evaluation of maize dhokla
Authors: Shobha Doddanagappa , Neena Joshi , Jamuna Kariyanakatte Veeraiah , Vijayalakshmi Karki Gajanan , Prakash Nagabovanalli Basavarajappa
Published: November 2019

Application of fermentation technique is known to significantly enhance nutrient contents in foods and hence, this study was conducted to develop and evaluate fermented dhokla from maize. Different levels of maize semolina (600 μm) were mixed with bengal gram dhal (2:1, 3:1 and 4:1 ratios) and evaluated for acceptability using subjective and objective methods by taking rice dhokla (3:1) as control. Proximate composition, antinutrients, protein, and starch digestibility of the best accepted ratio at different stages of preparation (raw ingredients‐R, after soaking‐S, after fermenting‐F, and after steam cooking‐C) were analyzed by standard procedures. The taste (8.60), texture (8.80), and overall acceptability (8.32) were superior for 3:1 ratio of maize dhokla. Low chewiness value noticed in the 3:1 combination of maize dhokla indicated soft nature of the product. Reduction of phytic acid (610.58–451.98 mg in maize, 360.49–73.81 mg in rice), polyphenol (490.86–102.28 mg in maize, 279.78–95.13 mg in rice), and tannin (210.11–104.13 mg in maize, 138.36–86.05 mg in rice) content upon fermentation and cooking was observed with concomitant increase in mineral, protein, and starch digestibility.

Practical application

Maize is being produced on a large scale and only 16% is used for human consumption in India. This is largely due to nonavailability of maize based food products suitable for human consumption to add value to the crop. In this study, maize was incorporated in traditional fermented product dhokla. The advantages of low cost natural fermentation were witnessed with improvement in protein and starch digestibility along with reduction of antinutrients such as polyphenols, tannin, and phytic acids. Due to natural yellow color and good fermentability maize semolina was found highly suitable for the preparation of breakfast item dhokla with more porous and fluffiness compared to rice dhokla.
Machine learning based modeling of households: A regionalized bottom‐up approach to investigate consumption‐induced environmental impacts
Authors: Froemelt Andreas , Buffat René , Hellweg Stefanie
Published: November 2019

As major drivers of economy, households induce a large share of worldwide environmental impacts. The variability of local consumption patterns and associated environmental impacts needs to be quantified as an important starting point to devise targeted measures aimed at reducing household environmental footprints. The goal of this article is the development and appraisal of a comprehensive regionalized bottom‐up model that assesses realistic environmental profiles for individual households in a specific region. For this purpose, a physically based building energy model, the results of an agent‐based transport simulation, and a data‐driven household consumption model were interlinked within a new probability‐based classification framework and applied to the case of Switzerland. The resulting model predicts the demands in about 400 different consumption areas for each Swiss household by considering its particular circumstances and produces a realistic picture of variability in household environmental footprints. An analysis of the model results on a municipal level reveals per‐capita income, population density, buildings' age, and household structure as possible drivers of municipal carbon footprints. While higher‐emission municipalities are located in rural areas and tend to show higher shares of older buildings, lower‐emission communities have larger proportions of families and can be found in highly populated regions by trend. However, the opposing effects of various variables observed in this analysis confirm the importance of a model that is able to capture regional distinctions. The overall model constitutes a comprehensive information base supporting policymakers in understanding consumption patterns in their region and deriving environmental strategies tailored to their specific population.
Ritual Contingency: Teasing and the Politics of Participation
Authors: Sweet Nikolas
Published: November 2019

This article analyzes the naming ceremony of a young girl in a village in southeastern Senegal to show how kola nuts distributed during the course of such rituals provide material channels through which individuals managed inclusion across participation frameworks. Even for those not in attendance, distributed kola co‐constituted states of participation and witnessing, in which recipients could subsequently report about such events as ratified authorities. After being excluded from this naming ceremony, a woman performed a teasing nickname of the child to be named, which was subsequently voiced throughout the community as a form of dissent. Such routines of teasing offer forms of value transformation in which individuals could redirect and recontextualize material objects, and in so doing, articulate claims to community inclusion and participation. Lifetime events offer contexts in which increasingly dispersed social networks evaluate participation and community membership. Although teasing has often been offered in general terms as a form of resistance, an interdiscursive, material analysis has the capacity to show how it serves as a form of social power and value transformation.
Divorce and Diverging Poverty Rates: A Risk‐and‐Vulnerability Approach
Authors: Hogendoorn Bram , Leopold Thomas , Bol Thijs
Published: November 2019

Objective

This study offers a new approach to analyzing life course inequalities and applies it to the link between divorce and poverty.

Background

Previous research has suggested that divorce drives cumulative inequality between education groups during the life course. Two pathways play a role in this process: the educational gradient in the risk of divorce and the educational gradient in economic vulnerability to divorce. Both pathways should be studied simultaneously to understand how divorce drives inequality.

Method

The authors used administrative data from the Netherlands, following the marriage cohorts 2003 to 2005 (N = 179,018) during a period of 10 years. Decomposition analyses estimated the contributions of the gradients in divorce risk and vulnerability to poverty differences during the life course.

Results

In the 10 years following marriage, the fraction of the educational difference in poverty explained by divorce was 12% in the overall population and 26% in mothers. Among childless men and women, divorce increased poverty differences due mainly to greater economic vulnerability of the lower educated. Among mothers, divorce increased poverty differences due to both higher risk and greater vulnerability of the lower educated. Among fathers, divorce was unrelated to poverty.

Conclusion

Divorce is a major driver of cumulative inequality during the life course.
Influence of exogenous acid protease in broiler chickens fed corn–soybean meal‐based diets
Authors: Hu Jing , Ingale Santosh , Rathi Piyush , Zhang Jian Ying , Kim In Ho
Published: November 2019

This study was conducted to determine the influence of exogenous acid protease (EAP) on growth performance, blood profiles, excreta noxious gas emissions, ileum digesta viscosity and apparent ileal digestibility in broilers. A total of 600 1‐d‐old broilers with average initial body weight of 47.0 ± 0.2 g were used in a 5‐week feeding trial. The broilers were randomly allotted to 1 of 4 treatments with 10 replicate pens per treatment and 15 birds per cage. Dietary treatments consisted of: CON, basal diets; EAP1, CON + 2,700 exogenous acid protease unite (APU)/kg; EAP2, CON + 5,400 APU/kg; EAP3, CON + 8,100 APU/kg. The body weight gain (BWG) had a linear improvement when chicks fed 8,100 AP/kg diets from d 18 to 35 and overall (p < .05). Lower feed conversion ratio (FCR) was obtained in broilers fed 5,400 APU/kg and 8,100 APU/kg as compared with the CON during overall (p < .05). Birds fed diets supplemented with EAP diet led to a linear increase in the ileal digestibility of crude protein, energy and amino acids (lysine, methionine, cystine, threonine, isoleucine, leucine, histidine and tryptophan) compared with CON group (p < .05). In conclusion, based on our results, we suggest that supplementation with EAP diet was effective in improving growth performance through increasing ileal digestibility of some nutrients (crude protein, energy and amino acids) in broilers.
Characteristics and risk factors for mortality of invasive non‐Aspergillus mould infections in patients with haematologic diseases: A single‐centre 7‐year cohort study
Authors: Lee Hyeon‐Jeong , Cho Sung‐Yeon , Lee Dong‐Gun , Park Chulmin , Chun Hye‐Sun , Park Yeon‐Joon
Published: November 2019

Since mould‐active azole prophylaxis has become a standard approach for patients with high‐risk haematologic diseases, the epidemiology of invasive fungal infections (IFIs) has shifted towards non‐Aspergillus moulds. It was aimed to identify the epidemiology and characteristics of non‐Aspergillus invasive mould infections (NAIMIs). Proven/probable NAIMIs developed in patients with haematologic diseases were reviewed from January 2011 to August 2018 at Catholic Hematology hospital, Seoul, Korea. There were 689 patients with proven/probable invasive mould infections; of them, 46 (47 isolates) were diagnosed with NAIMIs. Fungi of the Mucorales order (n = 27, 57.4%) were the most common causative fungi, followed by Fusarium (n = 9, 19.1%). Thirty‐four patients (73.9%) had neutropenia upon diagnosis of NAIMIs, and 13 (28.3%) were allogeneic stem cell transplantation recipients. The most common site of NAIMIs was the lung (n = 27, 58.7%), followed by disseminated infections (n = 8, 17.4%). There were 23.9% (n = 11) breakthrough IFIs, and 73.9% (n = 34) had co‐existing bacterial or viral infections. The overall mortality at 6 and 12 weeks was 30.4% and 39.1%, respectively. Breakthrough IFIs (adjusted hazards ratio [aHR] = 1.99, 95% CI: 1.3‐4.41, P = .031) and surgical treatment (aHR = 0.09, 95% CI: 0.02‐0.45, P = .003) were independently associated with 6‐week overall mortality. NAIMIs were not rare and occur as a complex form of infection often accompanied by breakthrough/mixed/concurrent IFIs and bacterial or viral infections. More active diagnostic efforts for NAIMIs are needed.
Trade‐in for Cash or for Upgrade? Dynamic Pricing with Customer Choice
Authors: Xiao Yongbo , Zhou Sean X.
Published: November 2019

Trade‐in programs for electronics products, e.g., mobile phones, have been increasingly popular. These programs target at customers (we call them “bargainers”) who seek to salvage or upgrade their old devices. There are two widely adopted trade‐in options: trade‐in‐for‐upgrade and trade‐in‐for‐cash. In this study, we consider a firm who offers both trade‐in options, that is, a hybrid trade‐in program, to acquire old products, then refurbishes and resells them, together with new product over a finite selling horizon. The bargainers choose which option to trade in their products while new customers decide whether to buy a new product or a refurbished one. When the selling price of new product is exogenous, we derive the optimal trade‐in prices of old product and resale price of refurbished product. We show that the optimal trade‐in and resale policies are of a threshold‐type and trade‐in‐for‐upgrade should be offered with a premium refund (compared to trade‐in‐for‐cash) only in early periods of the selling horizon. We further consider two variants of the above base model. In the first extension, the new product has a fixed amount of initial inventory and is not replenishable during the selling horizon. In the second extension, the new product price can also be determined by the firm. Our numerical results demonstrate that the hybrid trade‐in program could generate significantly more profit than either upgrade‐only or cash‐only trade‐in program.
From the stench of death to an antidote for plant aluminium toxicity
Authors: Law Simon R.
Published: November 2019

Putrescine is a member of a group of aliphatic compounds, known as polyamines, which are derived from the breakdown of amino acids in living (and dead) cells. Along with the grimly named cadaverine, putrescine was discovered in 1885 by the German physician Ludwig Brieger, who identified these polyamines as the primary constituent of the foul odours we associate with the rot and putrification of flesh. From this morbid origin, it is difficult to believe that putrescine has since been recognised as having numerous beneficial roles for living cells, ranging from increasing the tolerance of plants to biotic and abiotic stresses to possible roles in treating major mood disorders in humans. In this issue of Physiologia Plantarum, Zhu et al. (2019) describes how the addition of putrescine to the roots of rice (Oryza sativa) can alter the building blocks of the cell wall and, in doing so, alleviate aluminium toxicity.
Control of Air-Ventilated Cavity Under Ship Hull in Abnormal Waves
Authors: Matveev Konstantin I.
Published: November 2019

Practical implementation of ship drag reduction techniques can lead to substantial fuel savings and lessening environmental impacts of maritime transportation. One of such technologies is based on injecting air underneath ship hulls, which results in the formation of thin air cavities that decrease the wetted hull surface and hence its frictional drag. In realistic sea wave conditions, however, these cavities become unsteady and may easily disintegrate upon interaction with high-amplitude abnormal waves. In this study, the air-cavity dynamics in such situations is simulated with a potential flow model and empirical correlations. A method for controlling the air cavity by varying the air supply rate is numerically investigated. It is shown that degradation of the air-cavity power savings in the event of a rogue wave passing can be partly mitigated by briefly boosting the air supply right after the abnormal wave occurrence. For one considered example, it is found that 20% of power savings is lost in a condition with abnormal waves and constant air supply. In case of temporary augmentation of air injection, the overall decrease of power savings is reduced to 10%.
Shape Optimization of a Trumpet-Tipped LVAD Inflow Cannula to Reduce Blood Damage Using a Genetic Algorithm
Authors: Nassau Christopher J. , Agarwal Ramesh K.
Published: November 2019

Use of computational fluid dynamics (CFD) in the field of blood-contacting medical device design and analysis has been growing in recent years. For example, the U.S. Food and Drug Administration (FDA) Center of Devices and Radiological Health (CDRH) has accelerated interest in industry and academia with nozzle and blood pump benchmarks to uncover best practices and to hopefully elevate the status of CFD to be applied as a safety analysis tool for medical devices. One area, not discussed as often as the pure simulation is the design optimization of hemodynamic devices. A systematic shape “optimization” should be distinguished from a simple “design improvement” by performing many flow field computations and design iterations to improve performance. In this paper, the shape optimization of a trumpet-tipped inflow cannula is presented using a single-objective genetic algorithm (GA) to minimize the blood damage. Many varying accounts in the literature have pointed to the advantages of the trumpet-tipped left ventricular assist device (LVAD) cannula for low blood damage and uniform velocity distribution with little to no backflow when compared to other shapes such as blunt, beveled and caged cannulas.
Experimental Study and Modelling of the Tip-Leakage Flow for an Isolated Fixed Blade
Authors: Deveaux B. , Fournis C. , Brion V. , Marty J. , Dazin A.
Published: November 2019

The tip-leakage flow has detrimental effects on the performance of compressors. In this paper the effects of gap height and incoming casing boundary layer thickness are analyzed. Velocity and total pressure measurements are carried out in a plane behind the trailing edge of an isolated fixed blade. The total pressure loss is decomposed in a vortex loss and a wake loss. It appears that the increase of total pressure losses with the gap height comes essentially from the vortex part. This observation motivated the development of a model based on an analogy with a jet in crossflow to estimate the tip-leakage vortex circulation. The predictions of this model are consistent with the experimental data for gaps smaller than 4% of chord.
Derivation of an Amplitude Equation for Weakly Nonlinear Pressure Waves of a Very High Frequency in a Compressible Liquid Containing Many Microbubbles
Authors: Akutsu Ryosuke , Kanagawa Tetsuya , Uchiyama Yusuke
Published: November 2019

The present paper theoretically treats weakly nonlinear propagation of plane progressive waves in an initially quiescent compressible liquid containing a tremendously large number of spherical gas bubbles, focusing on the derivation of an amplitude evolution equation (i.e., nonlinear wave equation). We emphasize the following points: (i) the compressibility of the liquid phase, which has long been neglected, is considered; (ii) the wave propagates with a large phase velocity exceeding the speed of sound in pure water; (iii) bubbles are not created or annihilated. From the method of multiple scales with an appropriate scaling of three nondimensional parameters, we can derive an attenuated nonlinear Schrödinger (NLS) equation, where the phase velocity is larger than the speed of sound in a pure liquid.
Consideration of CFD Analysis Accuracy of Box Fan
Authors: Tomimatsu Shigeyuki , Kato Chisachi
Published: November 2019

This CFD benchmark activity for a box fan has been conducted through the Industrial Committee for Supercomputing Promotion (ICSCP) and the Fan Noise Prediction Working Group from the “Promotion of Practical Use of HPC in Turbomachinery” Subcommittee established in the Turbomachinery Society of Japan. In this benchmark activity, various CFD software has been used.

In this study, ANSYS CFX 18.2 is used and the difference in results are investigated by changing the turbulence model and the mesh model. The results between the k-epsilon model and the Shear Stress Transport (SST) model show a reverse trend. That is to say, the k-epsilon model overestimates the pressure difference at the high flow range and the SST model underestimates it at the low flow range compared with the experimental result. In order to improve these numerical results, CFD analysis is conducted by changing mesh models. The number of the blade surface mesh, and the initial height, height ratio, and number of prism layers are changed, but there is no improvement through these approaches. In this paper, CFD verification and validation are conducted for the box fan.
Effect of Active Flow Control Mechanisms on the Turbulent Flow Structures
Authors: Tsubokura Satoshi , Kawaguchi Yasuo
Published: November 2019

Blowing or suction on the wall is expected to efficiently control the characteristics of wall-bounded turbulent flow such as wall-frictional coefficient. To understand the mechanism of the change of turbulence statistics caused by this method, we experimentally investigated the effect of uniformly blowing and suction flow on a turbulent structure in a relatively simple flow, fully developed turbulent channel flow. For blowing, the friction coefficient and the thickness of the low-speed region increased. These results imply that the boundary layer becomes unstable because the growth of viscous sublayer is rapid and the time-scale of reaching a critical thickness is small due to the blowing from the wall. On the other hand, for suction, the opposite tendency appeared.
Impact of Differing Water Contents on Electrostatic Charging
Authors: Weishaar Philipp C. , Mielke Tobias , Schmitz Katharina
Published: November 2019

Hydraulic fluids underwent significant changes in their composition in these past years, which led to an increase in poor conductivity. Since well-established standards for specifying a hydraulic fluid, such as ISO 11158, make no mention of the electric conductivity, the awareness for potential complications is low. With some applications electrostatic discharges contribute to a shortened service life of the hydraulic fluid and the filter elements. Recent work on cavitation and its different forms suggest an underestimated impact of the relative humidity on fluid characteristics and the tendency for cavitation. In relation to electrostatic charges, the relative humidity of a fluid is seldom considered. The results presented in this paper offer an initial observation of the effect of relative humidity on electrostatic charging. To this end three hydraulic fluids, satisfying the specifications of an HLP 46, are prepared with three different levels of relative humidity at 20°C. Subsequently the nine samples are tested with a small-scale test bench in order to garner a qualitative comparison of the charging tendency.
X-Ray Flow Visualization of Cyclopentane Hydrate Formation
Authors: Pillers Roy A. , Morgan Timothy B. , Heindel Theodore J. , Estanga Douglas
Published: November 2019

Natural gas hydrates form under high pressure and low-temperature environments common in deepwater off-shore petroleum production operations. Once hydrates form, they can agglomerate and deposit resulting in solid plugs within the piping system, which could require extensive downtime for remediation and recommission of the systems. Hydrate plug formation is difficult to characterize because of the challenging environments in which they form, the lack of instrumentation for such environments, and the fast reaction time compared to other blocking mechanisms. This study explores the use of X-ray flow visualization, including X-ray radiography and X-ray computed tomography, to help characterize hydrate formation in a laboratory setting. A structure II hydrate was formed in a concentric cylinder mixing tank where a mixture of distilled water and cyclopentane was stirred in the inner tank while the outer tank was cooled. As the tank cooled, the distilled water-cyclopentane mixture converted to hydrate, which was captured with X-ray radiographic videos. Once formed, X-ray computed tomography images were acquired to gather 3D reconstructed images of the hydrate with and without liquid present in the mixing tank. It was shown that X-ray imaging could provide a qualitative assessment of hydrate formation. Quantitative measures were challenging because of the limited contrast between the hydrate and liquid region.
Experimental Investigation for the Better Control of Flows Over a Simplified Vehicle Configuration With Dielectric Barrier Discharge Plasma Actuator
Authors: Sekimoto Satoshi , Shimizu Keigo , Nakashima Takuji , Fujii Kozo , Hiraoka Takenori , Nouzawa Takahide
Published: November 2019

Reduction of aerodynamic drag is a big subject for vehicle development from the point of view of the global environment conservation. On the other hand, the optimization of vehicle body for less aerodynamic drag strictly defines the body shape and limits the freedom of design. Therefore, novel flow control technology is desired to enable small aerodynamic drag with excellent design. In the present study, a dielectric barrier discharge plasma actuator is installed on a simplified vehicle model with the round-shaped rear end to control the flow around the rear end for drag reduction. Experiments are conducted with the model (L840mm × H300mm × W300mm) in a Gottingen type wind tunnel with a ground plate. Reynolds number is fixed at 1,200,000, corresponding to a freestream velocity of approximately 20 m/s. Aerodynamic force, surface pressure near the rear edge, and total pressure and velocity field are measured. In the result of aerodynamic force measurement, driving plasma actuator successfully achieves 3% drag reduction at the most. Flow field measurement of total pressure and two-component velocity shows the difference of vortex structure near the rear end between off and on. Plasma actuation in this study can move the vortex structure away from the body surface rather than suppress the vortex or circulation.
Resolvent Analysis of Turbulent Friction Drag Reduction by Manipulation of Mean Velocity Profile
Authors: Uekusa Riko , Kawagoe Aika , Nabae Yusuke , Fukagata Koji
Published: November 2019

In the present study, we numerically manipulate the mean velocity profile of a turbulent channel flow and assess the friction drag reduction performance by using resolvent analysis. Building on the implication obtained from Kühnen et al. (Nat. Phys., Vol. 14, 2017, pp. 386–390) that modifying mean velocity profile flat leads to significant drag reduction, we first introduce two functions for turbulent mean velocity, which can express ‘flattened’ profiles: one is derived based on the turbulent viscosity model proposed by Reynolds & Tiederman (J. Fluid Mech., Vol. 658, 2010, pp. 336–382), and the other is based on the mean velocity profile of laminar flow. These functions are used as the mean velocity profile for the resolvent analysis, and the flatness of the resulting profiles is characterized by two different measures. As a result, we confirm that, friction drag reduction is achieved if the turbulent mean velocity profile is ‘flattened’. However, we also find that the flatness of the mean velocity profile in the center of the channel alone is not enough to evaluate the drag reduction performance.
Numerical Study on Flow-Induced Vibration Characteristics of Three-Dimensional Hydrofoil in Cavitating Flow
Authors: Wang Chang , Liu Yuan-qing , Du Te-zhuan , Wang Yi-wei
Published: November 2019

With the increasing demand of higher performance and efficiencies for marine propulsion and hydropower system, structures became more flexible and were subjected to high flow rates. Cavitation-structure interaction has become one of the major issues for most engineering applications. In order to analyze the characteristics of unsteady cavitating flow induced vibration, the cloud cavitation flow over three dimensional NACA66 hydrofoil is studied by numerical simulation in this paper. The cavitating flow is modeled by large eddy simulation method and Zwart cavitation model, and the structural vibration model of three dimensional hydrofoil is established. The numerical calculation of fluid-solid coupling is realized based on ANSYS Workbench. The main dimensionless parameters of three-dimensional hydrofoil cavitation flow-induced vibration are obtained by means of dimensional analysis, including density ratio, cavitation number, Reynolds number, and the frequency ratio of flow to structure. The changes of cavity morphology during the cloud cavitation development of flexible hydrofoil and the flow-induced vibration characteristics under cloud cavitation flow of flexible hydrofoil are analyzed. The results showed that the periodic development of cavitation can be divided into three stages: the growth of attached cavity, the development of re-entrant jet and the shedding of cavity in cloud cavitaion stage. The centroid displacement of the free end of the flexible hydrofoil varies periodically with time at the stage of cloud cavitation. The hydrofoil vibration is affected by the development of cloud cavitation, and the vibration frequency corresponds to the shedding frequency of cloud cavitation.
Flow Measurement in Stented Left Coronary Artery Models
Authors: Ono Kensuke , Yamamoto Ken , Tsukahara Takahiro , Motosuke Masahiro , Kawamoto Hiroyoshi , Tahara Satoko , Tanaka Kentaro , Nakamura Sunao
Published: November 2019

Ischemic heart disease, a generic term for angina pectoris and myocardial infarction, is caused by blood flow failure due to a lesion generated in the coronary artery of the heart. Because the ischemic heart disease causes fatal problems, a stent placement technique called the percutaneous coronary intervention (PCI) is frequently performed to expand coarctated arteries to recover the function. However, although the PCI technique is a less-invasive technique, there is a risk of complications such as stent thrombosis and restenosis due to the placed stent. In order to understand the cause and the mechanism of the complications, effects of the stent placement and the stent shape on the blood flow is experimentally investigated. Silicone left coronary artery models were prepared to perform particle tracking velocimetry (PTV) and calculated the wall shear stress (WSS). The measurement results show that the flow structure and the WSS are changed depending on the deformation of the stent and the location of the placed stent.
Tracker: An Opensource Particle Tracking Velocimetry (PTV) Application Applied to Multiphase Flow Reactors
Authors: Weber Justin , Bobek Michael , Rowan Steven , Yang Jingsi , Breault Ronald
Published: November 2019

The US Department of Energy’s National Energy Technology Laboratory is pursuing the development of advanced energy conversion technologies, many of which use gas-solid reactors such as fluidized beds and risers. To understand these units and provide high fidelity particle velocities for model development and validation efforts, particle tracking velocimetry (PTV) is typically used and remains one of only a few ways to extract particle velocities from dense multiphase flow experiments. Combined with the rapidly improving cameras (higher frame rates, higher resolutions, and lower cost) and access to high performance computers, new particle tracking tools are needed.

Tracker is an opensource, cross platform particle tracking velocimetry application for tracking objects in videos and image stacks. The goal of this project is to provide a tool that is, open source, continuously developed, does not rely on expensive software, parallel, has a graphical user interface (GUI), one continuous pipeline (from reading the file to post processing), well documented, and continuously tested and verified.

The application has extensive preprocessing tools, two tracking methods including poly-projection and template matching, visualization tools, and post-processing tools. The techniques are tested using both synthetic data and real experimental images. The application is extremely flexible and is easily extended to other tracking techniques, with plans to add correlation-based algorithms and optical flow algorithms.

The high-fidelity data being generated is now being used to validate computational fluid dynamic models that then will be used to predict the performance of these reactors, helping to achieve the US Department of Energy’s goal of developing novel, compact gas-solid reactors.
Reynolds-Averaged Navier-Stokes Modeling of Turbulent Rayleigh-Taylor, Richtmyer-Meshkov, and Kelvin-Helmholtz Mixing Using a Higher-Order Shock-Capturing Method
Authors: Schilling Oleg
Published: November 2019

A numerical implementation of a large number of Reynolds-averaged Navier–Stokes (RANS) models based on two-, three-, four-equation, and Reynolds stress turbulence models (using either the turbulent kinetic energy dissipation rate or the turbulent lengthscale) in an Eulerian, finite-difference shock-capturing code is described. The code uses third-order weighted essentially nonoscillatory (WENO) reconstruction of the advective fluxes, and second- or fourth-order central difference derivatives for the computation of spatial gradients. A third-order TVD Runge–Kutta time-evolution scheme is used to evolve the fields in time. Improved closures for the turbulence production terms, compressibility corrections, mixture transport coefficients, and a consistent initialization methodology for the turbulent fields are briefly summarized. The code framework allows for systematic comparisons of detailed predictions from a variety of turbulence models of increasing complexity. Applications of the code with selected K–ε based models are illustrated for each of the three instabilities. Simulations of Rayleigh–Taylor unstable flows for Atwood numbers 0.1–0.9 are shown to be consistent with previous implicit LES (ILES) results and with the expectation of increased asymmetry in the mixing layer characteristics with increasing stratification. Simulations of reshocked Richtmyer–Meshkov turbulent mixing corresponding to experiments with light-to-heavy transition in air/sulfur hexafluoride and incident shock Mach number Mas = 1.50, and heavy-to-light transition in sulfur hexafluoride/air with Mas = 1.45 are shown to be in generally good agreement with both pre- and post-reshock mixing layer widths. Finally, simulations of the seven Brown–Roshko Kelvin–Helmholtz experiments with various velocity and density ratios using nitrogen, helium, and air are shown to give mixing layer predictions in good agreement with data. The results indicate that the numerical algorithms and turbulence models are suitable for simulating these classes of inhomogeneous turbulent flows.
Numerical Analysis of Steady Blowing Based Active Flow Control for Flow Over Ahmed Body
Authors: Shah Bansal , Basu Debashis
Published: November 2019

A numerical study is conducted to investigate fluidic actuation with steady injection for active flow control and drag reduction in an Ahmed body. Numerical results are obtained for the unsteady three-dimensional Navier Stokes equations for both baseline as well as steady injection cases. This study examines the use of active flow control devices at the rear of the 25-deg Ahmed model to reduce drag by controlling an unsteady wake. The present work demonstrates that URANS model with grid refinement at critical locations can accurately describe the aerodynamics around the bluff body with computational time of several days compared to several weeks with traditional LES simulations. In order to modify the wake and reduce the pressure drag, active flow control technique using steady blowing was applied through a narrow slit along all rear edges of the model. The effect of inlet velocity for the baseline simulations was analyzed. Computed Results showed AFC achieves significant reduction in the drag coefficient (Cd) values over the baseline simulations.
Cavitation in Co-Rotating Tip Vortices
Authors: Koncoski J. J. , Krane M. H. , Welz J. P. , Hanson D. R. , Willits S. M. , Kunz R. F.
Published: November 2019

This work documents flow characterization and cavitation inception of a co-rotating vortex pair shed from a single fin with a rounded tip at zero angle of attack. The fin was outfitted with a removable tip fabricated using a rapid prototype method. The co-rotating vortices result from surface discontinuities on the removable tip, near a hard wax fairing used to cover the tip attachment bolt. The vortices are shed at different locations along the chord. Flow visualization by oil paint and developed cavitation, and SPIV of the near-wake, indicate that a strong vortex is shed at the trailing edge, while a weaker vortex is shed at 82% chord. Horizontal wandering of the vortices is uncorrelated. Vertical wandering of the vortices is characterized by opposing oscillations about their mutual center. Acoustic cavitation inception in the water tunnel environment is discerned at an index 13% greater than visual detection of cavitation, and occurs within one chord of the trailing edge. The influence of the co-rotating vortex system on cavitation inception must be determined from comparison with measurements of a solitary vortex generated by analogous geometry.
Formation Characteristics of Two-Phase Drops From Coaxial Nozzles
Authors: Kamatani Naoya , Ogata Satoshi
Published: November 2019

The purpose of this study is to clarify the formation characteristics and production conditions of two-layer droplets using coaxial nozzle. In this study, we focus on Newtonian fluid only to pay attention to the fundamental formation characteristics of two-layer droplet. Also, the three liquids flowing in the apparatus were assumed to have the same viscosity and density. First, theoretical equations concerning the outer diameters of the single layer droplet and the two-layer droplet were obtained, and a conditional expression for detaching both nozzles simultaneously from the nozzle in dripping was obtained. These theoretical equations were verified using numerical analysis. By analyzing with various parameters changed, the following six formation modes could be confirmed. 2 interface both dripping, 2 interface both jetting, Outer interface is jetting and The inner interface is dripping, 2 interface comes into contact and the encapsulated liquid is discharged to the outside, Two or more droplets are formed in the interior, Liquid droplets containing liquid droplets and liquid droplets not containing liquid droplets are alternately formed. The validity of each theoretical expression and conditional expression was also be confirmed.
A Numerical Study on the Low Limit Auto-Ignition Temperature of Syngas and Modification of Chemical Kinetic Mechanism
Authors: Jang Seung Eon , Park Jin , Han Sang Hyeon , Kim Hong Jip , Jung Ki Sung , Yoo Chun Sang
Published: November 2019

In this study, the auto ignition with low limit temperature of syngas has been numerically investigated using a 2-D numerical analysis. Previous study showed that auto ignition was observed at above 860 K in co-flow jet experiments using syngas and dry air. However, the auto ignition at this low temperature range could not be predicted with existing chemical mechanisms. Inconsistency of the auto ignition temperature between the experimental and numerical results is thought to be due to the inaccuracy of the chemical kinetic mechanism. The prediction of ignition delay time and sensitivity analysis for each chemical kinetic mechanism were performed to verify the reasons of the inconsistency between the experimental and numerical results. The results which were calculated using the various mechanisms showed significantly differences in the ignition delay time. In this study, we intend to analyze the reason of discrepancy to predict the auto ignition with low pressure and low temperature region of syngas and to improve the chemical kinetic mechanism. A sensitive analysis has been done to investigate the reaction steps which affected the ignition delay time significantly, and the reaction rate of the selected reaction step was modified. Through the modified chemical kinetic mechanism, we could identify the auto ignition in the low temperature region from the 2-D numerical results. Then CEMA (Chemical Explosive Mode Analysis) was used to validate the 2-D numerical analysis with modified chemical kinetic mechanism. From the validation, the calculated λexp, EI, and PI showed reasonable results, so we expect that the modified chemical kinetic mechanism can be used in various low temperature region.
Evaluate a New Pump Design Using CFD Simulation
Authors: Ding Hui , Greenfield Benjamin
Published: November 2019

This paper describes how CFD simulations were used to help evaluating a centrifugal pump performance. The simulated pump was designed totally from scratch. Many aspects of pump performance characteristics were predicted based on the geometry generated using a pump design software. Especially the effects of the free spin of the 3rd rotor in a 3 stage pump assembly on overall performance were evaluated. Pump models, simulation techniques, and simulation approaches will be presented in detail. Simulation results will be discussed and compared with available test data.