bluuebunny/crossref_metadata_2025 huggingface dataset:
Medication Use Quality and Safety in Older Adults: 2018 Update
Authors: Ailabouni Nagham J. , Marcum Zachary A. , Schmader Kenneth E. , Gray Shelly L.
Published: November 2019

Improving the quality of medication use and medication safety is an important priority for prescribers who care for older adults. The objective of this article was to identify key articles from 2018 that address these issues. In addition, we selected four of these articles to annotate, critique, and discuss their broader implications for clinical practice. The first study highlights a cluster‐randomized trial that utilized a pharmacist‐led education‐based intervention delivered to both patients and physicians to deprescribe four types of inappropriate medications (sedative‐hypnotics, first‐generation antihistamines, selective nonsteroidal anti‐inflammatory drugs, and glyburide). The second study, a nested case‐control study using data from within the UK Clinical Practice Research Datalink, examined the association between anticholinergic exposure, overall and by anticholinergic medication class, and dementia risk in 40 770 older adults. The third study, a longitudinal cohort study of 1028 Swedish older adults, examined the association between antihypertensive medications and incident dementia. The last study was a randomized, double‐blind, placebo‐controlled trial that investigated the effect of daily low‐dose aspirin (100 mg) for primary prevention on cardiovascular events and major hemorrhage in 19 144 community‐dwelling older adults. Collectively, this current article provides insight into the pertinent topics of medication use quality and safety in older adults and helps raise awareness about optimal prescribing in older adults. J Am Geriatr Soc 67:2458–2462, 2019
Evaluation of the Idexx ProCyte Dx® for analysis of canine cerebrospinal fluid
Authors: Romero‐Fernandez N. , Ives E. J. , Fraser A. R. , Williams T. L. , Paul A. E. H.
Published: November 2019

Objectives

To assess the utility of the Idexx ProCyte Dx® haematology analyser for assessing total nucleated cell count and differential cell counts in canine cerebrospinal fluid.

Materials and Methods

Seventy‐three client‐owned dogs undergoing investigations for pyrexia and/or neurological signs were prospectively included. Cerebrospinal fluid samples were assessed using an Idexx ProCyte Dx® analyser and the results were compared to those obtained with the external laboratory reference standard.

Results

The Idexx ProCyte Dx® performed with good sensitivity (92.6%) and moderate specificity (67.4%) for total nucleated cell count when compared to the reference standard. Qualitative assessment of the Idexx ProCyte Dx® scatter plots, and quantitative assessment of differential cell counts where available, appeared to correlate well with the external laboratory manual differential cell counts, with a good‐to‐high agreement in 25 of 26 samples (96.2%).

Clinical Significance

The Idexx ProCyte Dx® analyser performed well in determining the total nucleated cell count and differential cell counts in canine cerebrospinal fluid when compared to a reference standard of external laboratory analysis, except for cell counts higher than ~1000/μL. As the Idexx ProCyte Dx® currently only provides a cell count in 10 cells/μL increments, software modification may improve agreement between the two methods. As in human medicine, automated methods may prove useful in the future for cerebrospinal fluid analysis in addition to manual assessment, particularly in an emergency setting.
Total Hip Arthroplasty for Crowe Type IV Hip Dysplasia: Surgical Techniques and Postoperative Complications
Authors: Shi Xiao‐tong , Li Chao‐feng , Han Yu , Song Ya , Li Shu‐xuan , Liu Jian‐guo
Published: November 2019

Total hip arthroplasty (THA) of Crowe type IV developmental dysplasia of the hip (DDH) is challenging. Although traditional (lateral, posterolateral, and posterior) THA approaches have been used with great anatomic success, they damage periarticular muscles, which are already quite weak in type IV DDH. The recently developed direct anterior approach (DAA) can provide an inter‐nerve and inter‐muscle approach for THA of type IV dysplasia hips. However, femur exposure with the DAA could be difficult during surgery and it is hard to apply femoral shortening osteotomy. THA techniques used for type IV DDH include anatomic hip center techniques (true acetabular reconstruction) and high hip center techniques, wherein an acetabulum is reconstructed above the original one. Although anatomic construction of the hip center is considered “the gold standard” treatment, it is impossible if the anatomical acetabular is too small and shallow. Procedures used to support type IV DDH reduction with anatomic hip center techniques include greater trochanter osteotomy, lesser trochanter osteotomy, and subtrochanteric osteotomy. However, these techniques have yet to be standardized, and it is unclear which is best for type IV DDH. One‐state and two‐state non‐osteotomy reduction techniques have also been introduced to treat type IV DDH. Potential complications of THA performed in patients with type IV DDH include leg length discrepancy (LLD), peri‐operative femur fracture, nonunion of the osteotomy site, and nerve injury. It is worth noting that nowadays an increasing number of Crowe type IV DDH patients are more sensitive to postoperative LLD.
Immune deposits in skin vessels of patients with acute hemorrhagic edema of young children: A systematic literature review
Authors: Pellanda Giorgia , Lava Sebastiano A. G. , Milani Gregorio P. , Bianchetti Mario G. , Ferrarini Alessandra , Vanoni Federica
Published: November 2019

Background

Acute hemorrhagic edema of young children is a benign skin‐limited vasculitis mainly affecting children 2 to 24 months of age, which is often considered the infantile variant of immunoglobulin A vasculitis (Henoch‐Schönlein purpura). In most cases, the diagnosis is made on a clinical basis without a skin biopsy.

Methods

A systematic review of the literature was performed to examine the reported prevalence of vascular immune deposits in skin biopsies of patients with acute hemorrhagic edema of young children.

Results

Testing for vascular immune deposits was performed in 75 cases (64 boys and 11 girls aged from 3.5 to 72, median 11 months) published between 1970 and 2018. Vessel wall deposition of complement C3 was seen in 40 cases. Immunoglobulin M (N = 24), immunoglobulin A (N = 21), immunoglobulin G (N = 13), and immunoglobulin E (N = 3) were less frequently detected. Gender, age, clinical features, and disease duration were not statistically different in cases with and without vessel wall deposition of immunoglobulin A.

Conclusion

Immune deposits in skin vessels, most frequently complement C3, are common in subjects with acute hemorrhagic edema of young children, providing furhter evidence that acute hemorrhagic edema, immunoglobulin A vasculitis, and pauci‐immune vasculitides are different entities.
The influence on renal function of ibuprofen treatment for patent ductus arteriosus in extremely low birthweight infants
Authors: Nishizaki Naoto , Matsuda Akina , Yoneyama Toshiyuki , Watanabe Akiko , Obinata Kaoru , Shimizu Toshiaki
Published: November 2019

Background

Ibuprofen (IBU) has been used recently for the treatment of patent ductus arteriosus (PDA) in Japan. We aimed to investigate the efficacy and adverse events of IBU and compare them with those of indomethacin (IND) as PDA treatment for extremely low‐birthweight infants (ELBWIs), focusing on short‐term renal function.

Methods

A case‐control study was conducted on 16 ELBWIs. The data from eligible patients were divided into two groups. Ten patients had undergone IND treatment (IND group) between January 2017 and June 2018, whereas six had undergone IBU treatment (IBU group) for PDA between July 2018 and December 2018. The IND group received 0.1 mg/kg/12h IND IV infusion for three doses, whereas the IBU group received 10 mg/kg IV IBU infusion followed by 5 mg/kg/day for 2 days. We compared the efficacy for PDA closure and renal impairment between the two groups.

Results

No significant differences in primary closure rates and the PDA ligation required were observed between the two groups. No significant differences were observed between the incidence of intraventricular hemorrhage and gastrointestinal complications in both groups. Changes in urine volume (%) in the IBU group were significantly higher than in the IND group at 24–36 h post‐administration. The urinary L‐type fatty acid binding protein concentration level at 7 days of life was significantly lower in the IBU group than in the IND group.

Conclusion

Although IBU was comparable to IND in PDA closure rate, IBU was superior to short‐term renal injury in ELBWIs.
Unique cytologic and histologic features of a suspected cutaneous xanthoma in a dog
Authors: Russell Elise B. , Courtman Natalie F.
Published: November 2019

A 4‐year‐old spayed female American Staffordshire Terrier presented to the U‐Vet Animal Hospital, Werribee, Australia, with a cutaneous mass that had been slowly growing over 12 months. Cytologic evaluation showed cohesive to individualized, vacuolated spindled cells often arranged in a perivascular pattern. The mass was completely excised, and the histopathologic examination demonstrated sheets of vacuolated spindled to round cells expanding the full thickness of the dermis. The cells demonstrated both Iba1 and CD18 antibody binding, leading to an initial interpretation of histiocytic sarcoma. Given the discordance with the clinical presentation, further immunohistochemistry (IHC) was performed. The cells demonstrated strong CD204 antibody binding and did not bind E‐cadherin antibody, consistent with a dermal macrophage origin. Ki‐67 antibody binding was regionally variable from <5% to 25%, with more regions that had low Ki‐67 expression. A fasted serum biochemistry panel revealed hypertriglyceridemia and persistent hypercholesterolemia. Based on clinical, microscopic, biochemical, and IHC results, the final interpretation was an indolent dermal histiocytic proliferation of macrophage origin, with a preference for cutaneous xanthoma or reactive dermal fibrohistiocytoma.
Humorous interaction, language learning, and social media
Authors: Chik Alice
Published: November 2019

The rising popularity of language learning social network websites (LLSNSs) like Duolingo and Hellolingo reconfigures traditional language learning by providing structured learning materials and spaces for social interaction among language learners. The social interactive aspects have been celebrated to be the facilitating reason to advance learning. Many of these LLSNSs also claim to have millions of active users. This is then the first time in the history of language teaching and learning that we witness a massive number of language learners gathering on the same platform for learning and interaction. On many of these LLSNSs, English learning frequently dominates. This study adopts an observational ethnographic approach to collect natural interaction between English learners of different linguistic backgrounds. Based on interaction collected from about 2,000 threads, this paper examines the ways in which learners use multilingual resources to make sense of humorous English sentences. Findings suggest that in addition to translation, learners frequently draw on word play and popular culture on these LLSNSs to illustrate and enhance learning.
Effect of Ankle-Pivot Misalignment and Upward Ankle Vertical Displacement on Stability and Equilibrium Location for an Ankle-Hip Model of Balance on a Balance Board
Authors: Chumacero-Polanco Erik , Yang James , Chagdes James
Published: November 2019

During individual training on a balance board (BB), misalignment between the ankle joint and the BB axis of rotation may exist. The ankle-pivot misalignment influences the dynamics of human balance and more importantly, the stability properties of the equilibrium positions of the human-BB dynamical system. Similarly, ankle displacement in the upward direction with respect to the BB pivot also plays a critical role in the stability properties of the human-BB system. This paper investigates these effects through bifurcation analyses performed to the ankle-hip model of balance on a BB developed in our previous work. By using local bifurcation analyses, we have obtained the stability regions of the upright posture (UP) of a human-BB model of balance in different parameter spaces. The stability regions are delimited by Hopf, pitchfork, and saddle-node bifurcation curves in some selected parameter spaces. Results show that ankle-pivot misalignment has an impact on the location of the Hopf and unfolds the pitchfork bifurcation curves (found in the aligned case) into saddle-node bifurcation curves. Moreover, ankle-pivot misalignment breaks the mirror symmetry of upright static equilibrium positions and induces the establishment of equilibrium positions away from the vertical UP. With respect to the ankle vertical displacement, it has a minimal impact on the location of the pitchfork bifurcation curves but has a large impact on the location of the Hopf bifurcation curves, especially when combined with large BB time delay. This suggests that a larger ankle vertical displacement may result in sway oscillations of larger amplitude. The analyses also provide insight into different mechanisms of stability that can be found in the ankle-hip model of balance on a BB, namely, limit cycle oscillations and leaning postures. If an individual suffers from neuropathy, results from this study can be useful for researchers and clinicians in understanding what types of instabilities might be encountered, and during rehabilitation how to position the subjects carefully to avoid inadvertent instabilities.
Effects of Baffle Width on Heat Transfer to an Immersed Coil Heat Exchanger: Experimental Optimization
Authors: Nicodemus Julia Haltiwanger , Huang Xiaoqi , Dentinger Emily , Petitt Kyle , Smith Joshua H.
Published: November 2019

In this work, we investigate the effects of the width of an annular baffle region on natural convection heat transfer to an immersed, coiled heat exchanger in an otherwise quiescent sensible hot water storage tank. In the experiments, the coiled heat exchanger sits in an annular region created by the tank wall and a straight, cylindrical baffle. The width of this baffle region is 1.5, 2, 3, or 4 times the heat exchanger diameter. These experiments are compared to each other and to corresponding control experiments with no baffle. In general, all baffles create considerable benefits over their respective control experiments, consistent with past studies. The considered metrics of heat transfer rate, fraction of energy discharged from the tank, heat exchanger outlet temperature, and heat exchanger effectiveness show that heat transfer is improved slightly by narrowing the baffle region. For example, relative to their respective controls, the energy extracted from the tank after 30 min of discharge in the 1.5D, 2D, 3D, and 4D experiments is 23.3%, 20.8%, 18.1%, and 14.6% higher, respectively. This improvement in natural convection heat transfer as the baffle region narrows is attributed to the increasing thermal stratification observed with increasingly narrow baffle regions.
Two Flow Models for Designing Hydrostatic Bearings With Porous Material
Authors: Böhle M. , Gu Y. , Schimpf A.
Published: November 2019

The numerical prediction of load capacity, stiffness, power loss of hydrostatic journal bearings must be performed for technical applications. In this contribution hydrostatic bearings consisting of porous material are considered. Porous hydrostatic bearings have the advantage that no pressure erosion occurs and that the flow medium can be led homogenously to the gap between shaft and bearing. It is still a problem to design such bearings because the flow in the porous material must be taken into account. There is a simple flow model (SFM) available to calculate quickly the load capacity, stiffness, power loss. This model which is based on the assumption that the flow inside the porous material is axially symmetric works well provided that the eccentricity is small (dimensionless eccentricity e/h0 < 0.5). For large eccentricities — larger than e/h0 > 0.5 the axially symmetric assumption is too strong violated and the results for load capacity, stiffness become inaccurate. Therefore an improved model was developed which is described in the present contribution. This improved model couples the Reynolds equation for hydrodynamic lubrication (REHL) with Darcy Law as it had already been done for the aforementioned fast working SFM. The improved model is not based on the axially symmetric assumption but models the flow completely inside the porous material, i.e. Darcys Law is applied for the porous material without making any assumptions. By the application of the new model, its short name is Full Darcy’s Law (FDL) Model, bearings with high eccentricities can be designed. The application of Darcys Law leads to a Laplace equation for the static pressure distribution in the porous material which is coupled with the REHL. It is described how the resulting equation system is solved by a finite difference method. In this contribution the fast working SFM is described shortly again. The main emphasis lies on the introduction of the FDL-model which needs more computer resources for designing a porous bearing than the SFM. It is explained in detail how the coupling between Darcy Law (Laplace equation) and the REHL is realized. A comparison between the results of both models is shown and the differences are interpreted. Additionally, CFD results are used in order to validate the results of the FDL-model.
Experimental Analysis of Turbulent Wake Development Behind a Permeable Cylinder
Authors: Horimoto Yasufumi , Suzuki Yusuke , Hagiwara Kazuki , Kawaguchi Yasuo
Published: November 2019

To investigate the effect of permeability on turbulent wake behind a cylinder in uniform flow, we conduct particle image velocimetry on turbulent wake behind permeable cylinders, which are made of mesh sheets, of different permeabilities and compare the results with those for a solid cylinder. For relatively lower permeability, turbulent wake is quite similar to the case for a solid cylinder except for a slight shift in the streamwise direction of the reversed flow region implying turbulent Kármán vortex shedding. On the other hand, for higher permeability, the structure of turbulence is qualitatively different. More concretely, turbulent Kármán vortices disappear. Interestingly, however, the momentum deficit for such flow is comparable with that of a solid cylinder. This considerable momentum deficit can be understood with isotropic turbulence caused by the flow penetrating through the mesh constructing the cylinders. These results imply that turbulent wake behind a permeable cylinder involves dynamics both of wake and grid turbulence and the latter one dominates when permeability is sufficiently high.
Water Piston Engine for Marine Vehicle Propulsion
Authors: Asfar Khaled , Al-Smadi Eyad
Published: November 2019

This paper describes an environment friendly propulsion system with negligible noise. The Propulsion system is based on a novel engine called a water piston engine. All moving parts in the classical internal combustion engine are eliminated; the piston, connecting rod, and crankshaft. Also, cams and follower valves are replaced by solenoid valves which inject compressed air into the cylinders. A water column in the cylinder is used to replace the metallic piston. The water column itself inside the cylinder acts as a piston. This Water Piston Engine is powered by pressurized air only. So, a pressure vessel is used to store compressed air. The Pressure derived from the compressed air tanks is directly used in providing thrust by pushing the water out of the cylinder through a 90-degree elbow as a water jet. When the water is ejected from the cylinder and the air pressure inside the cylinder decreases to near atmospheric, the water that surrounds the engine fills the cylinder. Four cylinders are used; each two cylinders are fired simultaneously in order to maintain thrust.

This system uses an Arduino microcontroller unit to deal with how much time the pressurized air is needed to discharge the cylinder and to switch the airflow between the engine cylinders. Several field tests have been made in a lake. The experimental data were compared to the theoretical based data in addition to simulate this model using Ansys fluent. The advantages of this novel engine over internal combustion engines are clarified. Videos of the experiments are recorded.
The Effect of Model Parameters on CFD Simulation of a Thermosyphon
Authors: Wang Huiyu , Walters D. Keith , Walters Keisha B.
Published: November 2019

Both numerical and experimental studies have previously been carried out to investigate the heat transfer performance of the two-phase closed thermosyphon (TPCT). This paper investigates the performance of a commercially available computational fluid dynamics (CFD) solver (Ansys FLUENT) to predict the complex flow behavior of TPCTs, with special focus on modeling of the mass transfer phase change process. The present study uses four different sets of mass transfer coefficients for condensation and evaporation within a previously documented phase change model to determine their impact on the simulation results. The mass transfer coefficients effectively control the rate of transfer from liquid to vapor phase during evaporation and vice versa during condensation. The choice of coefficients is assumed to represent a balance between numerical accuracy and stability. A baseline simulation is performed for which both the evaporation and condensation coefficients are equal and set to default values. Three additional simulations vary the magnitude of the coefficients and adopt relative values based on density ratio following a recommended method that has been previously found to be effective for these simulations. Initial results show that the case with the highest coefficient of evaporation and coefficient for condensation based on the density ratio is in good agreement with available experimental data of overall thermal resistance of the TPCT., with predictive capability degrading as the values of the coefficients are reduced. Additionally, the 3D CFD models implemented in this study appear to successfully predict the phase change process and vital flow behavior inside the TPCTs, at least in a qualitative sense.
Analysis of Angular Velocities, Surrounding Air Pressure and Velocities of Various Designed Micro Vertical Axis Savonius Wind Turbines by the Computational Fluid Dynamics (CFD) Method
Authors: Manosroi W. , Tangtrakool T. , Lhaosornthong C.
Published: November 2019

The objective of this study is to analyze angular velocities, surrounding air pressure and velocities of various micro vertical axis Savonius wind turbine prototypes by the Computational Fluid Dynamics (CFD) method. The angular velocities of turbines are the basic parameters for determining the major parameters of the wind turbines, such as efficiency, torque, power and electricity etc. Eight models of the micro vertical axis Savonius wind turbine made of acrylic were designed by varying three parameters including the turbine distance between the pivot point and the tip, the distance between the apex curvature and the center plane curvature and the cross section types (circular, square, triangular and trapezoid). The eight models were divided into three groups including two models (B1, B2) with two different cross section types (triangle and rectangular) in the first group, three models (C1, C2, C3) with three different distances from the curvature tip to the centerline of 110, 85 and 40 millimeters in the second group and three models (D1, D2, D3) with different distances between the pivot point and the tip in the third group. Then, the angular velocities, the surrounding air pressure and velocities of the micro vertical axis Savonius wind turbine at the five wind speeds at 5.59, 7.67, 9.76, 10.45 and 11.84 m/s were measured and evaluated by the ANSYS program. The simulation by the CFD method of the angular velocities of the designed wind turbines was compared with the experimental results. Some discrepancies due to the absence of friction in the CFD results were observed. However, discrepancies between the simulation and the experimental results were decreased when the wind speed was increased due to the increase of torque and force in the experimental results which has overcome the turbine core friction. It has indicated that at the highest wind speed (11.84 m/s), the designed micro vertical axis Savonius circular cross section wind turbine with the curvature of the distance from the apex curvature to the center plane at 110 millimeters gave the highest turbine angular velocity of 441 rpm. At this highest turbine velocity by the CFD simulation, the high surrounding air pressure was not the smallest and the low turbine surrounding air pressure area was not the largest. This might be due to the effect of the suitable apex curvature distance to the center plane causing the efficient air flow to overcome the effect of the surrounding air pressure. The wind turbine of the second group gave the highest angular velocities followed by the first and the third group. These designed micro vertical axis Savonius wind turbines can be used as a preliminary model for the design and construction of the micro wind turbine to generate electricity at low wind speed region, such as Thailand.
Numerical Investigation of Tip Leakage Vortex Cavitation in Axial Waterjet Pump With Different Tip Gap Sizes
Authors: Xu Shun , Ji Bin , Long Xinping , Qian Zhongdong , Li Guibin , Zhou Jiajian
Published: November 2019

The flow field in the tip region of the axial-flow waterjet pump is very complex. Although it has been studied for many years, many relevant phenomena have still been a puzzle. In present paper, many detailed data on instantaneous inner structures of the tip leakage flow and evolution of the tip leakage vortex cavitation with different tip gap sizes are offered. The numerical simulation has been conducted by using SAS turbulence model and ZGB cavitation model to understand the cavitation-vortex interaction mechanism. The predicted cavitation performance exhibits a reasonable agreement with the experimental results. Based on the illustration, with the impeller tip gap size decreasing, the cavitation area in rotating region gradually decreases. The cavitation development enhances vorticity production in an axial-flow waterjet pump. Vortices are mainly located at the impeller tip leakage region. The analysis of the relative vorticity transport equation indicates that the baroclinic torque term and the vortex dilation term have significant effects on cavitation, the main contributor to vortex generation is the vortex dilation term. In addition, in the impeller tip region, the effect of viscous diffusion term cannot be ignored, and the cavitation area has a larger amplitude of pressure pulsation.
Experimental Study on Abrasion and Cavitation Resistance of Non-Metallic Coating Materials for Pump
Authors: Liu Hou-lin , Cao Man-hui , Chen Jie , Wang Yong , Wang Cheng-bin
Published: November 2019

The protection of the flow-passage components of pump by using coating is an important method to increase wear resistance. This paper aims at examining abrasion resistance and cavitation erosion resistance of three typical non-metallic coating materials for pump including epoxy resin mortar, composite resin mortar and polyurethane. A wear-resistance test bench was built, using ultrasonic vibrating air eroding machine. Meanwhile, the main relative raw materials and formulas were introduced. The results indicate that: (1) The accumulated volume reduction of abrasion of composite resin mortar changes in an oblique waveform, and its abrasion resistance is better than that of epoxy resin mortar in a short period of time. The wear rate of epoxy resin mortar and composite resin mortar is higher than that of polyurethane. The total wear volume of epoxy resin mortar, composite resin mortar and polyurethane is decreased by 8.74%, 9.89% and 0.58% respectively within 30h of anti-wear test time; (2) The accumulated volume reduction of cavitation erosion of epoxy resin mortar is proportional to the time. In anti-cavitation erosion test time of 26 h, the erosion volume of composite resin mortar, polyurethane and epoxy resin mortar cavitation is reduced by 0.44%, 0.29% and 0.35%, respectively. It shows that cavitation erosion resistance of three coating materials is similar, while polyurethane materials have the best abrasion resistance.
Effect of Rotating Speed on Performance of Electrical Submersible Pump
Authors: Yang Yang , Zhou Ling , Shi Weidong , Wang Chuan , Li Wei , Agarwal Ramesh
Published: November 2019

High speed rotating pump is the current trend in pump’s development and application, which has the advantages of compact size and energy-saving features. The electrical submersible pump, typically called an ESP, is an efficient and reliable artificial-lift method for lifting moderate to high volumes of fluids from wellbores, which have been wildly used for oil or groundwater extraction. To verify the similarity of pump performance under different rotating speeds, a typical ESP is selected as the model pump. By employing the numerical simulation and performance testing methods, the external performance characteristics and internal flow fields under different rotating speeds of the pump are studied. The entire computational domain is established by two stages ESP, and then meshed with the high-quality structured grid based on the Q-type and Y-type block topology. Grid sensitivity analysis is carried out to determine the appropriate mesh density for mesh independent solution. SST k-ω turbulence model with standard wall function in conjunction with Reynolds-Averaged Navier-Stokes (RANS) equations is used to solve the steady flow field. The results show that the increase in the rotating speed could increase the ESP’s head significantly. ESP’s external characteristics under different speeds meet the similar conversion rule quite well. In addition, the flow field distributions in the main flow components of the pump have great similarity at different rotating speeds. The experimental test results for a prototype show good agreement with the simulation results, including the pump’s head, efficiency and axial force. This paper provides a data set for further understanding of the effects of rotating speeds on ESP’s performance and inner flow fields.
Assessment of Noise Signature for a Cavitating Centrifugal Pump
Authors: Stephen Christopher , Sivasailam Kumaraswamy
Published: November 2019

In recent days, sophisticated instruments have emerged to obtain an online measurement of performance parameters from centrifugal pump of different kinds and the signals can be directed to the hands of pump user through mobile application. With this in mind, a centrifugal pump of low specific speed was chosen for cavitation studies from 80% to 120% of flow rate and for three different speeds. An assessment was carried out for cavitation noise signature from those operating condition of pumps. The result of cavitation noise based on peak magnitude as well as average of noise revealed a nature and it depends on the flow rate with respect to nominal flow rate. The noise envelope for the flow rate at best efficiency and above was having similar trend whereas at flows less than duty point it was totally different. So the criteria for finding the deviation in noise cannot be uniform for all flow rates. In this paper, the method adapted was to impose a trend line to the measured cavitation noise information to find out the deviation with respect to normal operating condition. It was concluded that detection of abnormality in pumps due to cavitation effects requires the operating condition to be diagnosed first and the proper criteria for deviation in noise has to be imposed.
Evaluations of Shape Parameter of Groove for Reducing Noise Generated From Rotating Tires
Authors: Ishiyama Junya , Fujii Kozo , Asada Kengo , Sekimoto Satoshi , Koishi Masataka , Ikeda Toshiyuki
Published: November 2019

Acoustic fields obtained by large-eddy simulations around a rotating tire with the grooves are investigated to clarify the relationships between the shape parameters of the grooves and the directivity of noise sound. To acquire acoustic field around the rotating tire, the large-eddy simulations using the sixth-order compact finite difference scheme and the tridiagonal filter are performed. The sixteen cases including the non-groove case are considered in the present study. To evaluate the acoustic noise from the groove, the sound pressure level (SPL) of each point is computed, and the difference between the cases with and without the groove is investigated. The obtained Results indicate that the width at the opening side of the groove strongly impacts on the acoustic field, and the acoustic noise is reduced as the width at the opening side increases. Additionally, the acoustic noise is reduced as the width at the bottom side increases. However, the depth and the area of the groove do not have a strong relation to the acoustic field. In the viewpoint of the noise directivity, larger the widths at the opening side and the bottom side, and the angle between the bottom and the side wall reduce the acoustic noise on the side of the rotating tire, while that in front of the tire increase. These results provide new insight into our understanding the mechanism of noise generated from the rotating tire with grooves and may help to make intelligent design for noise reduction.
Measurements of Dimension and Morphology of Solid Particles Volume With Digital In-Line Holography
Authors: Wang Yijie , Chen Jun
Published: November 2019

Digital in-line holography (DIH) has been applied to measure the 3D position of objects in a variety of applications, including bubbles and droplets in multi-phase flows, tracking particles in turbulence flows, etc. In addition to the 3D position, the morphology and dimension of the individual particles can also be extracted from the recorded hologram. In this study, a lens-less digital in-line holography setup is applied to measure the morphology and size of three kinds of solid particles (Wollastonite Powder, Pearl Mica Powder and Solder Powder), whose sizes range from several to hundreds of micrometers. The statistics of equivalent diameter, aspect ratio and circularity are introduced to describe the morphology and dimension of each kind of particles. Microscopic images of the particles are taken to verify the accuracy of measurements with DIH. The results measured from DIH are in good agreements with results from microscopic images.
Experimental Investigation on Influence of Inclination and Curved Surface of Ship Bottom in Air Lubrication Method
Authors: Kawakita Chiharu , Hamada Tatsuya
Published: November 2019

The air lubrication method, which mixes millimeter bubbles into the flow around the hull and reduces frictional resistance, is expected to have a large energy saving effect among a number of marine energy saving technologies. Concerning the frictional drag reduction effect using the air lubrication method, in this study, the frictional drag reduction effect was experimentally investigated for gas-liquid two phase flow considering the influence of inclination and curved surface of the ship bottom. Measurement of local shear stress and measurement of void fraction distribution near the wall surface were carried out and the correlation between local shear stress and local void fraction distribution was grasped.
Lab-Scale Wind Tunnel Experiment Test of Wind Turbine Blades for Performance Evaluation
Authors: Moon Jae Sang , Park Sung Soo , Yu Sung Ho , Kang Sangkyun , Lee Jang-Ho
Published: November 2019

This study evaluates the performance of a HAWT blade model using the lab-scale wind tunnel experiment. The small-scale wind turbine blade model has been designed based on the newly developed airfoil, KA2. A 3-blade rotor, based on the blade model, is tested using the digital wind tunnel. The performance is estimated by measuring the rotor-induced shaft torque. To estimate the performance properly, two different methods have been used depending on the blade rotation speed. Test results are compared with the theoretical estimation by BEM. This study provides the methodology to the performance test of wind turbine blades using lab-scale experiment. Moreover, results represent the applicability of the KA2 airfoil to wind turbine blades.
A Numerical Study on Flow Characteristics of Super Sonic Diffuser for the Position and Nose Cone Angles of Center Body
Authors: Lee Sunghun , Lee Myeongwon , Park Jin , Kim Hongjip
Published: November 2019

The center body diffuser is one of supersonic diffuser that can simulate high-altitude environment. There is center-body structure inside the diffuser, and a complex fluid flow is occurred inside the diffuser because of the interaction of the CB structure with gas exhausted from the nozzle outlet. In this study, starting point and flow characteristics of diffuser were investigated according to changing the CB nose cone angle and the length of distance between nozzle and CB structure. The differences of the supersonic flow were compared through each parameter of CB distance and CB nose angle. First changed parameter was length between nozzle and CB. According to the length of distance between nozzle and CB, axial momentum was developed and oblique shock wave moved front of CB from end of CB nose cone. Also, when CB position was located on a certain length, starting point of CBD decreased. Next change parameter was angle of CB nose cone. According to the angle raised, angle of oblique shock wave was raised and radial momentum of supersonic diffuser developed. But, according to radial momentum of supersonic flow over certain angle, the starting pressure of CBD increased. Because axial momentum which isolated vacuum chamber from atmospheric pressure. Through these CFD analysis results, it was shown that angle and length of distance between nozzle and CB influent performance of CBD.
Numerical and Experimental Study of Thermal Behavior of an Electric Fuse in Electric Vehicle Li-Ion Battery Packs
Authors: Pulugundla Gautam , Dubey Prahit
Published: November 2019

In this paper, we perform 3D CFD simulations to understand the thermal operation of a High Breaking Capacity (H.B.C.) electric fuse within a Li-ion battery pack. The main focus is on evaluating the thermal behavior of a commercially available H.B.C. fuse containing four notched silver fuse elements through a numerical and experimental study that investigates the effect of the magnitude of electric current. For the numerical analysis we perform time-accurate, conjugate heat transfer-based 3D CFD simulations on high spatial resolution grids with commercial CFD software STAR-CCM+. Specifically, we utilize an electrodynamic potential model to calculate current density and the corresponding Ohmic heat generation of the fuse. The results of the numerical simulations with temperature dependent fuse material properties are validated against the experimental temperature measurements. The spatial distribution of temperature, and current in the fuse and its connected components are also compared for various input current values to evaluate the thermal performance of the fuse under a range of operating conditions.
A Numerical Study of Turbulence Model and Rebound Model Effect on Erosion Simulations in an Electrical Submersible Pump (ESP)
Authors: Zhu Haiwen , Zhang Jun , Zhu Jianjun , Rutter Risa , Zhang Hong-Quan
Published: November 2019

Sand production is one of the most serious problems of electrical submersible pumps (ESPs). It is important to predict erosion rate and pump life under sand flow condition. However, erosion experiments on centrifugal pumps are difficult, expensive and time-consuming. Besides, the erosion on pump blades and shrouds are hard to be quantified. It is difficult to measure or scan the thickness of an inside flow channel. Therefore, computational fluid dynamic (CFD) method is a convenient way to forecast erosion failures of the pump. Although various erosion simulations were carried out for simple geometries, including pipelines, elbows, tees, and etc., erosion simulation methodology in a turbomachinery geometry should be carefully evaluated. Therefore, the effect of different turbulence models and rebound models are investigated in a 3-stage mixed type ESP by ANSYS Fluent Discrete Phase Model (DPM) simulations. The erosion rate is calculated and particle impact parameters are extracted by a User Define Function (UDF). Preliminary erosion simulation methodology recommendations were given in this study.
Reconstruction of RANS Model and Cross-Validation of Flow Field Based on Tensor Basis Neural Network
Authors: Song Xudong , Zhang Zhen , Wang Yiwei , Ye Shuran , Huang Chenguang
Published: November 2019

The solution of the Reynolds-averaged Navier-Stokes (RANS) equation has been widely used in engineering problems. However, this model does not provide satisfactory prediction accuracy. Because the widely used eddy viscosity model assumes a linear relationship between the Reynolds stress and the average strain rate tensor and these linear models cannot capture the anisotropic characteristics of the actual flow. In this paper, two kinds of flow field structures of two-dimensional cylindrical flow and circular tube jet are calculated by using the RANS model. Secondly, in order to improve the prediction accuracy of the RANS model, the Reynolds stress of the RANS model is reconstructed by the tensor basis neural network algorithm based on nonlinear eddy viscosity model. Finally, the model trained by neural network is cross-validated, and compare the cross-test results with the traditional RANS k-eps model. The results show that the multi-layer neural network method has achieved good results in turbulence model reconstruction.
High Speed Transient Flow in Manifolds
Authors: Findanis Nicholas
Published: November 2019

Flows in manifolds is a ubiquitous and important area to implement flow improvements. In almost all applications of industrial pipe flows, there is the requirement to distribute the flow of fluid. There is a deficiency of studies in the area of flow distribution in manifolds with high speed flows. The present work is aimed at providing a further understanding of transient high speed flow distribution in manifolds. The different manifold configurations were analysed computationally. A comparison was focused between through the different aspect ratio manifolds. The velocity field and the eddy viscosity parameters where compared between the simulated flow models to ascertain the key features in the distributed flow field and especially, to determine the areas that showed greater flow recirculation or flow eddies and the separated flow regions. The CFD study was conducted as a high speed flow/ compressible flow regime accounting for the ideal gas dynamic model being air as the working fluid. The study showed that the transient behaviour of flow field can significantly affect distribution of the flow depending on the aspect ratio and number of branches on the manifold. Efficiency gains can be achieved in high speed flows that can be of benefit in industrial and other engineered flow applications.
Measurement Wall Shear Stress Using MCF Rubber
Authors: Miyachi Shunya , Kubota Yoshihiro , Mochizuki Osamu , Shimada Kunio
Published: November 2019

The purpose of this study is the development of an elastic sensor for the measurement of wall shear stress induced by flow. We used a flexible sensor by MCF rubber. The MCF is named of Magnetic Compound Fluid. This functional material can be measured the force by change of electric conductivity with a deformation. The experiments were carried out with the basis of rotational viscometer. The results with MCF sensor sense the decreasing of wall shear stress with the decelerating the flow gradually. The results suggest the good responsivities for the force measurement.
Prediction of Drag Reduction Effect of Pulsating Control in Turbulent Pipe Flow by Machine Learning
Authors: Kobayashi Wataru , Shimura Takaaki , Mitsuishi Akihiko , Iwamoto Kaoru , Murata Akira
Published: November 2019

It has been widely expected that the pulsating control can reduce friction drag in various fluid systems. In order to maximize its effect, a prediction tool of drag reduction using pulsating control is required. The present study aims at the prediction of the drag reduction rate by machine learning. Multilayer perceptron (MLP) was applied as the machine learning method. Water was used as the working fluid. First, an automatic measurement system was constructed and drag reduction effect was evaluated by an experiment with various pulsation waveforms. The flow pulsation was generated by giving periodical acceleration and deceleration by a centrifugal pump in a closed circulation system. The bulk Reynolds number Reb ranges between 3400 and 3800. Next, the experiments were performed with over 5000 kinds of waveforms to make training and validation data for MLP. Within the data, the maximum drag reduction rate of 38.6% was observed. The friction coefficient Cf decreased during the acceleration period and increased during deceleration period. Finally, the drag reduction rate was predicted in three cases with different input parameters of MLP. The relationship between pulsation waveforms and the drag reduction effect was successfully predicted.
Research on Temperature Rise of Wet Clutch Based on Multi-Field Coupling
Authors: Wu Bangzhi , Qin Datong , Hu Jianjun , Zhang Qing
Published: November 2019

Wet clutch is widely used in vehicle power transmission, especially in dual clutch automatic transmission. However, due to the unclear understanding of clutch temperature distribution and its influencing factors, the clutch is prone to excessive temperature rise or even wear under severe working conditions or continuous starting conditions. In this paper, the finite element model of stress field distribution of friction pair is established by considering the non-uniform fixed constraint of clamping spring and the non-uniform contact of hydraulic cylinder. Based on the inclined groove structure of the friction plate, the numerical calculation model of the flow field in the groove is established by the finite volume method. On this basis, considering the time-varying characteristics of stress distribution and cooling flow field distribution of clutch friction pairs, a numerical calculation model of clutch temperature field is established, and a multi-field coupling calculation method of clutch is proposed. The distribution of temperature field under different working conditions during clutch engagement is obtained by numerical calculation. The results show that the temperature rise of clutch depends on the target speed of the clutch driving end and the load on the driven end. The research results can provide guidance for the design and control of the clutch.