bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Measurement of Heat Flux Partitioning in Boiling Heat Transfer
Authors: Richenderfer A. , Kossolapov A. , Seong J. H. , Saccone G. , Bucci M. , Buongiorno J. 
Published: October 2017

The development and validation of mechanistic boiling heat transfer models has been a focal point in the efforts to improve the efficiency and profitability of power generation systems, e.g. nuclear reactors. The primary goal of these models is improving the accuracy of boiling heat transfer simulations and reducing the uncertainty margins that affect both the design and the safety of a system. However, the emergence of these models has also stimulated the need for high-fidelity experiments and experimental data for validation and verification.
In this work we present first-of-a-kind data of heat flux partitioning in boiling heat transfer, obtained using cutting-edge diagnostics and post-processing techniques. A HSV camera was used to visualize the boiling surface at 10,000 frames per second with simultaneous front and side views of the two-phase flow. A high-speed IR camera was used to capture the 2-D radiative signal from the boiling surface to visualize bubble nucleation, growth and detachment at a 115 μm/pixel resolution at 2,500 frames per second. A coupled radiation-conduction calibration model was used to calibrate the IR data and extract the full local temperature and heat flux distributions on the boiling surface, which enable a direct measurement of the partitioned heat fluxes.
Here we report the results of investigations performed in flow boiling conditions with a mass flux of 500 kg/m2/s, at atmospheric pressure and 10 K of subcooling. These data will be leveraged to inform the development and validation of the next generation of mechanistic boiling heat transfer models, to be used in Computational Fluid Dynamics (CFD) codes for the design and the safety analysis of nuclear reactors.
Solids Erosion Patterns Developed by Pulse Jet Mixers
Authors: Bamberger Judith Ann , Pease Leonard F. , Minette Michael J. 
Published: October 2017

Millions of gallons of radioactive waste are stored in underground tanks at the Hanford Site in Washington State. This waste will be vitrified at the Waste Treatment and Immobilization Plant that is under construction. Vessels in the pretreatment portion of the plant are being configured for processing waste slurries with challenging physical and rheological properties that range from Newtonian slurries to non-Newtonian sludge. Pulse jet mixing (PJM) technology has been selected for mobilizing and mixing this waste. In the pulse jet mixing process, slurry is expelled from pulse tube nozzles directed towards the vessel floor. The expelled fluid forms a radial jet that erodes the settled layer of solids. The pulse tubes are configured in a ring or multiple rings and operate concurrently. The expelled fluid and mobilized solids traverse toward the center of the tank. At the tank center, the jets from pulse tubes in the ring collide and lift solids upward in a central plume. At the end of the pulse, when the desired fluid volume has been expelled from the pulse tube, the applied pressure switches to suction and the pulse tubes are refilled. This cycle is used to mobilize and mix the tank contents.
An initial step of the process is the erosion of solids from the vessel floor by the radial jets that form on the vessel floor beneath each pulse tube. Experiments have been conducted using simulants to evaluate the ability of the pulse jet mixing system radial jets to combine to develop the central upwell and lift solids in the vessel. These experiments were conducted at three scales using a range of granular simulants over a range of concentrations in vessels with elliptical, spherical, or flanged and dished bottoms. Process parameters evaluated experimentally include the velocity of fluid expelled from the pulse tube, the duration of the pulse and the ratio of pulse duration to cycle time. Videos taken from beneath the vessel show the growth of the cleared area beneath each pulse tube as a function of time during the pulse. The focus of this paper is to describe measurement techniques and compare and contrast erosion patterns developed from different simulants and pulse tube configurations. The cases are evaluated to determine how changes in process parameters affect the PJM’s ability to mobilize solids from the vessel floor.
Performance of Supercritical Slurry Jet Drilling System
Authors: Padsalgikar Ashwin , Dabirian Ramin , Oglesby Ken , Mohan Ram S. , Shoham Ovadia 
Published: October 2017

A slurry jet driller is a novel drilling method, which delivers an abrasive slurry and supercritical gas mixture, to an expander nozzle. The expanded fluids flowing out of the nozzle, energize the particles, which hit the target material and erode it, achieving drilling. The expansion of the gas from a super critical state to in situ pressure and temperature conditions is the driving mechanism of the drilling operation. The primary objective of this paper is to evaluate the feasibility of the novel slurry jet drilling system.
An experimental program is carried out for testing the performance of a slurry jet driller. The slurry is formed by mixing water with garnet particles, and a super critical carbon dioxide as the gas phase. The purpose of experiments is to evaluate the erosive nature of garnet rocks and to test the cutting efficiency of the nozzle. The acquired data show that the material removal rate increases with increase in the gas-slurry flow ratio, until a ratio of 1.5. A further increase in the flow ratio results in a reduction of the rate of material removal.
Improved nozzle geometry was obtained using a program written in MATLAB. Criteria used for geometry improvement was the force applied to the bottom of the drilled bore. A rudimentary model is developed for the prediction of material removal rate utilizing a slurry jet driller, which is presented in a dimensionless form. The model incorporates the important variables affecting the jet driller system performance, including fluid and target material properties, and particle velocity. A fair agreement is observed between model predictions and experimental data, exhibiting a 20% deviation.
A Low Cost Fabrication Method for Electrowetting Assisted Desiccation of Colloidal Droplets
Authors: Li Xi , Maki Kara L. , Schertzer Michael J. 
Published: October 2017

When colloidal droplets evaporate, material is often deposited at the periphery in a coffee-ring pattern. An understanding of colloidal transport and deposition in evaporating droplets is critical for optimization of many medical diagnostic devices and printing processes. This phenomenon can also be used for nanoparticle self-assembly, containerless materials processing, and manufacturing of flexible electronics. The forces affecting colloidal transport can be categorized as (i) convective effects, (ii) particle diffusion, and (iii) boundary effects. Knowledge of fluid flow in an evaporating droplet is required to understand particle transport when convection effects dominate over particle diffusion. The evaporative radial flow identified by Deegan et al. [1] is the result of contact line pinning and high evaporation flux at the contact line. Hu and Larson later identified that dominance of thermal Marangoni recirculation within the droplet can suppress ring formations by convecting particles to the center of the deposition.
Bhardwaj et al. [2] demonstrated that van der Walls and electrostatic forces can dominate colloidal transport and capture particles on the substrate to form uniform depositions. These effects are represented by the Derjaguin, Verwey, and Overbeek (DLVO) force. This force can attract or repel particles from the surface or other particles when they are separated by less than the Debye length. Attractive DLVO forces result in uniform depositions when they dominate over the evaporative and Marangoni flows in evaporating droplets. Particle capture on the substrate has also been achieved by antibodies-antigen reactions, or by leveraging magnetic and electrophoretic forces.
Particles can also be captured on the interface of evaporating droplets. Li et al. [3] observed uniform colloidal monolayers when water droplets were evaporated at elevated temperatures. They argued that particles were being captured on the interface in these cases as the particle diffusion rate was smaller than the velocity of the collapsing interface.
This work will find a low cost method for electrowetting assisted deposition and examine how electric fields can disrupt the interplay between convection, diffusion, and interface trapping in evaporating colloidal droplets. Application of AC and DC electric fields has the potential to suppress the coffee-ring effect by independently controlling the shape of the fluid interface, the contact angle hysteresis, and the motion of particles suspended in the droplet. This investigation will compare the interfacial evolution and deposition patterns left by evaporating protein laden droplets under AC and DC fields to examine their suitability for medical diagnostic applications.
Numerical and Experimental Study of the Rotational Behaviour of Flat Plates Falling Freely With Periodic Oscillating Motion
Authors: Hærvig Jakob , Jensen Anna L. , Pedersen Marie C. , Sørensen Henrik 
Published: October 2017

When a flat plate falls freely in periodic oscillating motion regime, unsteady fluid forces create additional lift force contributions due to the rotational behaviour. Computational fluid dynamics is used to simulate the free fall behaviour of a flat plate with aspect ratio β = 20 falling in two-dimensional flow with Reynolds number Re ≈ 10,000 and non-dimensional moment of inertia I* = 0.115. To validate the free fall trajectory obtained by computational fluid dynamics, video recordings are used. Based on the validated free fall computational fluid dynamics simulation, the instantaneous fluid forces and torques on the plate are obtained.
The validated simulations show significant deviations in per-pendicular and tangential force coefficients at the same angle of attack depending on the trajectory history of the plate. At low angles of attack below 5 deg, the tangential force differs significantly. Oppositely, the difference in the perpendicular force is most pronounced at high angles of attack. During a free fall, the angle of attack is below 5 deg in 70 % of the time. Furthermore, the angle of attack is only above 45 deg in less than 5 % of the time. Therefore, effort must be put into a more detailed description of the tangential force component, in order to improve the existing modelling framework for non-spherical particles.
A Theoretical Study of Saline Droplet Evaporation in Solar-Thermal Driven Full Separation Multi Effect Distillation (FS-MED) System
Authors: Wei Yan , Guo Penghua , Xu Ben , Rodriguez Thomas , Escobar Luis , Chirino Hermes 
Published: October 2017

The significant changes of population, environment and climate have led to the increased need for freshwater. However, the shortage of naturally available freshwater is becoming more frequent than ever. Desalination, removal of salt and other minerals from seawater, brackish water, and wastewater, is a promising solution to provide the increasing need of freshwater. Multi stage flashing (MSF) and multi effect distillation (MED) can be classified as conventional thermal-driven desalination technologies. Nevertheless, the disposal of high concentrated brine is a big environmental concern. Despite the tremendous improvements in conventional desalination technology, the desalination process is very energy consuming. Due to high expenses of the conventional energy resources, renewable energy sources can provide alternatives.
Considering the fact that Concentrated Solar Power (CSP) has been significantly developed during the past two decades, inorganic salts are the perfect candidates as Heat Transfer Fluid (HTF) for high temperature applications in solar thermal energy storage, fully separating water and salts in the desalination process arises naturally, since the leftover salts can be collected instead of disposing them to the environment. A full separation multi effect distillation (FSMED) system was proposed by other researchers, where the air fed to the full separation tank (FST) is preheated by a heat source, and the highly concentrated brine from the last effect is sprayed in the FST, so that the brine droplets can be completely evaporated by leaving behind inorganic salts. Obviously, the full separation process of salts and water involves multiphase heat and mass transfer. However, a key question is the characterization of the lifetime of brine droplets inside the FST during its entire evaporation process, and the effects from the internal circulation to droplet evaporation. If the droplet has strong internal circulation, the definition of two stages of evaporation becomes inaccurate, it has to be corrected based on the detailed calculation of time scale at each stage. In the current study, a 1D quasi-steady evaporation model was developed to characterize the effects from internal circulation to the life cycle of droplets in the FST, compared with the results using the dynamic evaporation model. To simplify the analysis, water droplet with impurity particles was considered, and a case study was also provided to compare the life cycle of water droplets without internal circulation. Finally, a correction to the definition of two-stage of water droplet evaporation was provided. It is expected that the computation results will be beneficial for thermal driven desalination community.
Effect of Surfactant (Foamer) Delivery Location on Horizontal Wells Deliquification
Authors: Barreto Carolina V. , Karami Hamidreza , Pereyra Eduardo , Sarica Cem 
Published: October 2017

One of the methods to unload liquid from gas wells is foam-assisted lift. The applied surfactant reduces the liquid surface tension facilitating foam stability, and consequently, reducing mixture density and gas slippage. In this experimental study, a 2-in ID facility consisting of a 64-ft lateral section followed by a 41-ft vertical section is used to determine the optimum surfactant delivery location in horizontal wells. Water and compressed air are the liquid and gas phases, and an anionic surfactant is applied continuously with fixed concentration. Lateral section inclination is varied between ±1°, and four injection points are tested, including one with a static mixer, used as an external source of agitation. Recorded parameters are flow pattern, pressure gradient, liquid holdup, and foam quality.
In the lateral section, the highest efficiency is obtained by using a static mixer causing significant drop in liquid holdup and increase in pressure drop due to frictional losses. All other injection points show similar behavior to the air-water case, due to negligible generated foam amid the existing flow pattern agitation. In the vertical section, all injection points show similar and significant drops in liquid holdup and delays in liquid loading onset compared to air-water case, and foam quality decreases as gas flow rate is reduced. Increasing the liquid flow rate causes increases in liquid holdup and pressure drop and shifts liquid loading onset to higher gas flow rates. The experimentally observed liquid loading onset is compared to the predictions of Turner et al. (1969), and a modification is proposed in this correlation to consider the effects of surfactant injection.
The number of experimental studies investigating foam effects on liquid loading is limited especially for off-vertical configurations. The results of this study provide an experimental source to optimize foam lift in deviated wells.
Modification of Near-Wall Turbulent Structure in Channel Flow by Dosing a Small Amount of Polymer Solution
Authors: Okamura Yushi , Kurose Tomohiro , Kawaguchi Yasuo 
Published: October 2017

The phenomenon known as Toms effect can impart viscoelasticity to a water flow when a small amount of water-soluble polymer is added. The resulting viscoelastic fluid generates viscoelastic stress in the flow, dramatically reducing the turbulent stress.
In this study, the spatial distribution of velocity is measured using a stereo-PIV method in the streamwise-spanwise plane parallel to the wall. Modification of the near wall turbulence by the polymer solution blown slowly from a permeable wall was investigated by analyzing the velocity distribution acquired by stereo-PIV measurements.
Experimental results reveal that streamwise local mean velocity decreases as the dosed polymer concentration increases. The skewness factor at this height shifts from 0 to positive by adding the polymer, which indicates intensified turbulent coherent structure. Moreover, the spatial two-point correlation function calculated from streamwise velocity fluctuations maintains its high correlation with the streamwise direction. It is consistent with the finding from the instantaneous velocity distribution, which shows that the flection of low-speed streaks is suppressed. Next, it is revealed that the normal velocity at the wall for low-speed fluid is decreased dramatically by polymer additives. Moreover, applying the quadrant analysis, it is confirmed that ejection events are suppressed with decreasing normal velocity at the wall. Suppression of ejection motion affects to the turbulence in the log law layer. We conclude that this is one reason that turbulence is suppressed in a wide range of the shear layer by polymer additives present only in the vicinity of the wall.
Experimental Investigation of the Influence of Inflow Conditions on the Flow Over an Extended Edge Escarpment
Authors: LoTufo J. , Siddiqui K. , Hangan H. 
Published: October 2017

Mean and turbulent flow behavior over a 1:50 scale model of a wind turbine site containing a local escarpment was investigated from wind directions of 230°, 270° and 300°. Flow from each direction contained vastly different local geometry at the same elevation.
Results showed separation regions are formed immediately downstream of the escarpment at each wind direction. It is observed that turbulence within the first 3 meters from the escarpment edge is strongest for inflow from 230° while flow from 300° shows similar trends with lower turbulence magnitude. Inflow from 270° had the most impactful effect on the flow behavior showing the largest wake region increasing in height with the distance from the leading edge. The results also show that the flow field below 55 m was effected by the local geometry of the escarpment leading up to and likely beyond the turbine location. It is concluded that the effects induced from local geometry may cause changes to dynamic loading and fatigue on both the turbine blades and tower.
Efficacy and Tolerability Outcomes of a Phase II, Randomized, Open-Label, Multicenter Study of a New Water-Dispersible Pediatric Formulation of Dihydroartemisinin-Piperaquine for the Treatment of Uncomplicated Plasmodium falciparum Malaria in African Infants
Authors: Gargano Nicola , Madrid Lola , Valentini Giovanni , D'Alessandro Umberto , Halidou Tinto , Sirima Sodiomon , Tshefu Antoinette , Mtoro Ali , Gesase Samwel ,   The Eurartesim Dispersible Study Group, Bassat Quique 
Published: October 2017

ABSTRACT

Artemisinin combination therapies are considered the mainstay of malaria treatment, but pediatric-friendly formulations for the treatment of infants are scarce. We sought to evaluate the efficacy and safety of a new dispersible-tablet formulation of dihydroartemisinin/piperaquine phosphate (DHA/PQP) in comparison to the marketed tablet (Eurartesim) in the treatment of infants with uncomplicated
Plasmodium falciparum
malaria. Reported here are the results of a large phase II, randomized, open-label, multicenter trial conducted in African infants (6 to 12 months of age) from Mozambique, Burkina Faso, The Gambia, the Democratic Republic of the Congo, and Tanzania. Primary efficacy endpoint was the PCR-corrected adequate clinical and parasitological response (ACPR) at day 28. Analysis was performed for the intention-to-treat (ITT) and per-protocol (PP) populations. A total of 201 patients received the dispersible-tablet formulation, and 99 received the conventional one administered as crushed tablets. At day 28, the PCR-corrected ACPRs were 86.9% (ITT) and 98.3% (PP) in the dispersible-tablet group and 84.9% (ITT) and 100% (PP) in the crushed-tablet group. At day 42, these values were 85.9% (ITT) and 96.5% (PP) in the dispersible-tablet group and 82.8% (ITT) and 96.4% (PP) in the crushed-tablet group. The comparison between survival curves for time to new infections showed no statistically significant differences (
P
= 0.409). The safety and tolerability profile for the two groups was similar in terms of type and frequency of adverse events and was consistent with that expected in African infants with malaria. A standard 3-day treatment with the new dispersible DHA/PQP formulation is as efficacious as the currently used tablet in African infants and has a comparable safety profile. (This trial was registered at ClinicalTrials.gov under registration no. NCT01992900.)
Pharmacokinetics of a Long-Acting Nanoformulated Dolutegravir Prodrug in Rhesus Macaques
Authors: McMillan JoEllyn , Szlachetka Adam , Slack Lara , Sillman Brady , Lamberty Benjamin , Morsey Brenda , Callen Shannon , Gautam Nagsen , Alnouti Yazen , Edagwa Benson , Gendelman Howard E. , Fox Howard S. 
Published: October 2017

ABSTRACT
A nanoformulated myristoylated dolutegravir prodrug (NMDTG) was prepared using good laboratory practice protocols. Intramuscular injection of NMDTG (118 ± 8 mg/ml, 25.5 mg of DTG equivalents/kg of body weight) to three rhesus macaques led to plasma DTG levels of 86 ± 12 and 28 ± 1 ng/ml on days 35 and 91, respectively. The NMDTG platform showed no significant adverse events. Further modification may further extend the drug's apparent half-life for human use.
Antifungal Activity of Oleylphosphocholine on
In Vitro
and
In Vivo Candida albicans
Biofilms
Authors: Holtappels Michelle , Swinnen Erwin , De Groef Lies , Wuyts Jurgen , Moons Lieve , Lagrou Katrien , Van Dijck Patrick , Kucharíková Soňa 
Published: October 2017

ABSTRACT

In this study, we investigated the potential antifungal activity of the alkylphospholipid oleylphosphocholine (OlPC), a structural analogue of miltefosine, on
in vitro
and
in vivo
Candida albicans
biofilm formation. The effect of OlPC on
in vitro
and
in vivo
C. albicans
biofilms inside triple-lumen polyurethane catheters was studied.
In vivo
biofilms were developed subcutaneously after catheter implantation on the lower back of Sprague-Dawley rats. Animals were treated orally with OlPC (20 mg/kg of body weight/day) for 7 days. The effect of OlPC on biofilms that developed on the mucosal surface was studied in an
ex vivo
model of oral candidiasis. The role of OlPC in
C. albicans
morphogenesis was investigated by using hypha-inducing media, namely, Lee, Spider, and RPMI 1640 media. OlPC displayed activity against both planktonic cells and
in vitro
C. albicans
biofilms. To completely abolish preformed, 24-h-old biofilms, higher concentrations (8, 10, and 13 mg/liter) were needed. Moreover, OlPC was able to reduce
C. albicans
biofilms formed by caspofungin-resistant clinical isolates and acted synergistically when combined with caspofungin. The daily oral administration of OlPC significantly reduced
in vivo
C. albicans
biofilms that developed subcutaneously. In addition, OlPC decreased biofilm formation on mucosal surfaces. Interestingly, the application of subinhibitory concentrations of OlPC already inhibited the yeast-to-hypha transition, a crucial virulence factor of
C. albicans
. We document, for the first time, the effects of OlPC on
C. albicans
cells and suggest the potential use of OlPC for the treatment of
C. albicans
biofilm-associated infections.