bluuebunny/crossref_metadata_2025_split huggingface dataset:
A randomized, prospective, comparative trial of a variable‐angle versus fixed‐angle endoscope for exploratory thoracoscopy in canine cadavers
Authors: Diamond Danielle M. , Scharf Valery F. , Chiu King Wa , Hash Jonathan A. , Mathews Kyle G. 
Published: June 2020

AbstractObjectiveTo compare the efficacy of a variable‐angle endoscope (VAE) for canine thoracoscopic exploration to a traditional fixed‐angle endoscope (FAE).Study designRandomized, prospective, comparative study.Sample populationFive fresh canine cadavers.MethodsTwelve predetermined anatomical locations were labeled after median sternotomy in each cadaveric thorax. Two board‐certified veterinary surgeons performed thoracoscopic evaluation of each thorax using a fixed‐angle (30°) and a variable‐angle (0°‐120°) endoscope with and without lungs mechanically ventilated. The order of surgeon, lung ventilation, and endoscope were determined using a randomized block design. Time to visualize each anatomical location was compared for surgeon, endoscope, and lung ventilation status. Primary outcome measures were time to individual anatomical location, total simulated thoracoscopic exploration time, and ability to identify anatomical location within the designated time period.ResultsLung ventilation (difference = 184 seconds, P = .015, 95% CI = 45‐342 seconds) and endoscope type (difference = 112 seconds, P = .029; 95% CI = 10‐213 seconds) had an effect on the cumulative time for complete thoracoscopic exploration. The VAE shortened the time to identify three of the 12 anatomical locations when controlling for the effects of lung ventilation. Use of the VAE did not improve time to identification for any locations compared to the FAE when lungs were not ventilated. The VAE facilitated significantly shorter cumulative thoracoscopic exploration time compared with the FAE. Failure to identify predetermined locations was more common with the FAE than with the VAE.ConclusionUse of a rigid VAE decreased cumulative thoracoscopic exploration time and provided an alternative to one‐lung ventilation for circumventing the visual impediments of lung ventilation.Clinical significanceThis cadaveric study provides evidence that one‐lung ventilation and use of a VAE may improve surgeon efficiency during exploratory thoracoscopy.
Farming for water; catchment management initiatives for reducing pesticides
Authors: Cooke Alexandra , Rettino Jodie , Flower Laura , Filby Katherine , Freer Adam 
Published: June 2020

AbstractPayment for Ecosystem Service (PES) schemes is increasingly being used to obtain and drive environmental improvements. This paper describes two PES schemes, designed by Severn Trent Water (STW) to manage metaldehyde; Farm to Tap, and Product Substitution. Data collected over three years of running the schemes indicate that they can reduce the mean metaldehyde concentration at the Water Treatment Works by up to 61%; however, in‐catchment concentrations are more variable. Participant usage and behavioural surveys identify that the majority of farmers will use multiple methods to manage their slug problem. Farmer initiatives developed where rewards are paid for metaldehyde reductions, regardless of the process(es) used (Farm to Tap), result in 12% more metaldehyde reduction than when product substitution is used alone. Going forward, catchment management is the long‐term, economic and sustainable option. Schemes like Farm to Tap and Product Substitution are crucial to achieve water quality improvements and wider environmental benefits.
Tribological Properties Improvement of Mo-Alloyed HfN Films With a High H/E Ratio at Elevated Temperatures
Authors: Liu Zhaoli , Li Hang , Li Jianliang , Huang Jiewen , Kong Jian , Xiong Dangsheng 
Published: June 2020

Abstract
In this study, the Mo-alloyed HfN films were prepared by DC-magnetron sputtering and studied their tribological properties at 25–600 °C under dry friction conditions. The relationship between H/E value and tribological properties at elevated temperature was illustrated. A single solid-solution phase was formed for all Hf-Mo-N films which with an FCC structure, and the H/E and H3/E2 values are increased. The film with x = 0.56 obtained a lower friction coefficient (0.4) and wear-rate (1.23 × 10−6 mm3/N m) at room temperature. At elevated temperature, this film maintained high structure stability, meanwhile, a dense and continuous oxide layer with lubrication was formed and tightly covered on the worn surface, that it obtained a lower coefficients of friction and better wear resistance.
Friction and Wear Performance of Oleate-Based Esters With Two-, Three-, and Four-Branched Molecular Structure in Pure Form and Mixture
Authors: Zulfattah Z. M. , Zulkifli N. W. M. , Masjuki H. H. , Harith M. H. , Syahir A. Z. , Norain I. , Yusoff M. N. A. M. , Jamshaid M. , Arslan A. 
Published: June 2020

Abstract
This paper reports the optimization of base oils composition involving oleate-based bio-lubricant that results in minimal wear-scar diameter (WSD) and coefficient of friction (COF) using mixture technique (MT) with simplex-lattice design (SLD). The lubricants used were neopenthylglycol dioleate (NPGDO), trimethylolpropane trioleate (TMPTO), and pentaerythritol etraoleate (PETO), which all are products of transesterification process between oleic acid and different types of alcohols becoming oleate ester. Fourball tester (FBT) was used to evaluate the resulting COF under ASTM-D4172 B testing procedure, while WSD was measured under an optical wear-scar measuring device. A second-order polynomial mathematical model was built and able to statistically predict the resulting WSD and COF of lubricant mixtures. In pure form, PETO exhibited the lowest COF with 0.06555 followed by NPGDO (+5.25%) and TMPTO (+16.97%). Meanwhile, NPGDO recorded the smallest WSD with 0.451 mm, followed by PETO (+4.04%) and TMPTO (+8.89%). Under SLD optimization technique, pure PETO was shown to give out the lowest COF; however, the lowest WSD was recorded by a mixture of 80.661 wt% PETO with 11.603 wt% TMPTO, and 7.736 wt% NPGDO resulting in 0.444 mm WSD; 5.53% lower wear than pure NPGDO.
A Coupled Eulerian–Lagrangian Model for Sliding Inception of Elastic–Plastic Spherical Contact
Authors: Zhang Haibo , Etsion Izhak 
Published: June 2020

AbstractCurrently existing finite element (FE) Lagrangian models of elastic–plastic spherical contact are costly in terms of computing time to reach vanishing tangential stiffness at sliding inception. A coupled Eulerian–Lagrangian (CEL) model with explicit dynamic analysis and power-law hardening is proposed to resolve this problem. The CEL model also avoids convergence problem caused by excessive distortion of elements in Lagrangian models. Static friction coefficient at sliding inception is investigated and compared with available experimental results. It is found that the proposed new CEL model is more efficient and accurate compared to previously published results of Lagrangian models.
Estimation of Pressure Drop of Two-Phase Flow in Horizontal Long Pipes Using Artificial Neural Networks
Authors: Shadloo Mostafa Safdari , Rahmat Amin , Karimipour Arash , Wongwises Somchai 
Published: June 2020

Abstract
Gas–liquid two-phase flows through long pipelines are one of the most common cases found in chemical, oil, and gas industries. In contrast to the gas/Newtonian liquid systems, the pressure drop has rarely been investigated for two-phase gas/non-Newtonian liquid systems in pipe flows. In this regard, an artificial neural networks (ANNs) model is presented by employing a large number of experimental data to predict the pressure drop for a wide range of operating conditions, pipe diameters, and fluid characteristics. Utilizing a multiple-layer perceptron neural network (MLPNN) model, the predicted pressure drop is in a good agreement with the experimental results. In most cases, the deviation of the predicted pressure drop from the experimental data does not exceed 5%. It is observed that the MLPNN provides more accurate results for horizontal pipelines in comparison with other empirical correlations that are commonly used in industrial applications.
Experimental Study and Pore Network Modeling of Formation Damage Induced by Fines Migration in Unconsolidated Sandstone Reservoirs
Authors: Han Xiaodong , Zhong Liguo , Liu Yigang , Fang Tao , Chen Cunliang 
Published: June 2020

Abstract
Fine migration is always considered as one of the major mechanisms that are responsible for formation damage. The unwanted reduction of reservoir permeability would result in the decline of water injection and consequent oil production, especially for the unconsolidated sandstone reservoir. For better understanding, the mechanisms of formation damage in pore-scale, a new three-dimensional pore-scale network model (PNM) is proposed and developed to simulate formation damage caused by particle detachment, migration, and capture in pore throats based on force analysis. Experiments are also conducted on the formation damage characteristics of an unconsolidated core. Both X-ray diffraction and scanning electron microscope (SEM) are applied to understand the microscopic reservoir properties. The experimental results show that the studied core has a strong flowrate sensitivity. A comparison between experimental results and PNM simulation results is conducted. The simulated results agree well with the experimental data, which approves the efficiency and accuracy of the PNM. Sensitivity analysis results show that larger particle sizes, higher flowrate, higher fluid viscosity, and lower ion concentration of the fluids would contribute to the formation damage, which could provide guidance for the development of unconsolidated sandstone reservoirs with strong sensitivity.
Membrane Distillation Desalination System With Gap Circulation and Cooling Using a Built-in Heat Exchanger
Authors: Khalifa Atia E. 
Published: June 2020

Abstract
A comprehensive experimental investigation is conducted to evaluate the performance of a new flux-enhanced compact water gap membrane distillation (WGMD) module design with gap circulation and cooling for water desalination. The new design uses a separate circulation loop to circulate the gap water, and a built-in heat exchanger coil implanted inside the coolant stream channel for cooling the circulated gap water. The WGMD modules with circulation and with circulation and cooling are compared with conventional WGMD without circulation. Variations of distillate flux, temperatures, and energy consumption are presented at different design operating conditions. Circulation and cooling of the gap water greatly enhance the output flux due to gap water motion and increase the temperature difference between membrane surfaces. However, the enhancement in flux was achieved at the expense of energy consumption. Circulation and cooling of gap water are more effective with bigger gap widths. Feed flowrate showed significant effects with gap water circulation and cooling. The electrical specific energy consumption (SEC) showed the best value of 7.9 and 8.8 kWh/m3 at a feed temperature of 70 °C for both conventional WGMD and WGMD with circulation modules, while the best value of SEC for the WGMD module with gap circulation and cooling was 9.4 kWh/m3 at a feed temperature of 80 °C.
Experimental and Numerical Study of Jet Impingement Cooling for Improved Gas Turbine Blade Internal Cooling With In-Line and Staggered Nozzle Arrays
Authors: Salem Abdel Rahman , Nourin Farah Nazifa , Abousabae Mohammed , Amano Ryoichi S. 
Published: June 2020

Abstract
Internal cooling of gas turbine blades is performed with the combination of impingement cooling and serpentine channels. Besides gas turbine blades, the other turbine components such as turbine guide vanes, rotor disks, and combustor wall can be cooled using jet impingement cooling. This study is focused on jet impingement cooling, in order to optimize the coolant flow, and provide the maximum amount of cooling using the minimum amount of coolant. The study compares between different nozzle configurations (in-line and staggered), two different Reynold's numbers (1500 and 2000), and different stand-off distances (Z/D) both experimentally and numerically. The Z/D considered are 3, 5, and 8. In jet impingement cooling, the jet of fluid strikes perpendicular to the target surface to be cooled with high velocity to dissipate the heat. The target surface is heated up by a direct current (DC) power source. The experimental results are obtained by means of thermal image processing of the captured infra-red (IR) thermal images of the target surface. Computational fluid dynamics (CFD) analysis were employed to predict the complex heat transfer and flow phenomena, primarily the line-averaged and area-averaged Nusselt number and the cross-flow effects. In the current investigation, the flow is confined along with the nozzle plate and two parallel surfaces forming a bi-directional channel (bi-directional exit). The results show a comparison between heat transfer enhancement with in-line and staggered nozzle arrays. It is observed that the peaks of the line-averaged Nusselt number (Nu) become less as the stand-off distance (Z/D) increases. It is also observed that the fluctuations in the stagnation heat transfer are caused by the impingement of the primary vortices originating from the jet nozzle exit.
Analytical Study to Use the Excess Digester Gas of Wastewater Treatment Plants
Authors: Nourin Farah Nazifa , Abbas Ahmad I. , Qandil Mohammad D. , Amano Ryoichi S. 
Published: June 2020

Abstract
This study presents an analytical method that can be used to enhance the power production rate and the energy-saving at wastewater treatment plants. The digester used at wastewater treatment plants produces digester gas by anaerobic digestion, with which biofuel production can be achieved. Biofuels can be used to meet some of the energy requirements of the wastewater treatment facility through combined heat and power (CHP) gas engines (cogeneration). Using micro gas turbine (MGT), a CHP technology can be introduced in wastewater treatment plants (WWTPs). The combination of MGTs and absorption chillers is a promising technology as it produces electricity, heating, and cooling simultaneously. The study demonstrated how the waste heat of MGTs could be used to drive absorption chillers. In this analytical study, a detailed technical and economic analysis is provided on the trigeneration system, i.e., the integration of MGTs and absorption chillers driven by waste digester gas of the wastewater treatment plants. It can meet the heating and cooling demands of the plants, which promote the reduction of utility costs. The technology presented is also useful for other thermal energy users.
Development of Viscosified Acid-Surfactant Solutions for Oilfield Applications: Rheological Properties
Authors: Fogang Lionel Talley , Kamal Muhammad Shahzad , Mahmoud Mohamed 
Published: June 2020

Abstract
Viscosified acids are desired in several oilfield applications such as in acid diversion and acid fracturing operations. The study aimed to delineate the rheological properties of a novel amine type surfactant and viscosified acid-surfactant solutions. The steady shear and dynamic rheological properties were evaluated by varying the surfactant, acid, and salt concentration. Such a study is required to gauge the suitability of the viscosifying agent in acid stimulation jobs. The surfactant solutions without acid showed shear-thinning behavior, whereas those with acid showed a Newtonian plateau over a wide shear rate range before undergoing shear thinning. This means that over a wide shear rate range, the acid-surfactant solutions become independent of applied shear. At low shear rates, the viscosity of the surfactant was higher compared with the surfactant-acid solution. However, at high shear rates, the viscosity of the surfactant was lower compared with the viscosity of the surfactant-acid solution. There was an optimal salt concentration that improved the viscosity and elasticity of the acid-surfactant solutions. Thus, the rheology of the surfactant solution can be improved by adding both acid and salt. The elastic properties of acid-surfactant solutions were also better compared with the elastic properties of pure surfactant. The addition of acid improved the elastic properties of the surfactant solutions. Constant viscosity over a range of shear rate is a suitable application for acid fracturing operations in which the acid leak-off will be minimal due to the high viscosity. Also, brines in most of the carbonate formation consist of high loading of calcium chloride which was found to have a positive effect on the viscosity. Increasing the calcium chloride leads to an increase in viscosity, and then subsequently decreases the viscosity. This shows that the acid and salt concentration plays a role in modifying the rheological properties of the surfactant solutions.
Comparison of Model Predictions and Performance Test Data for a Prototype Thermal Energy Storage Module
Authors: Helmns Dre , Carey Van P. , Kumar Navin , Banerjee Debjyoti , Muley Arun , Stoia Michael 
Published: June 2020

Abstract
Although model predictions of thermal energy storage (TES) performance have been explored in previous investigations, relevant test data that enable experimental validation of performance models have been limited. This is particularly true for high-performance TES designs that facilitate fast input and extraction of energy. In this paper, we present a summary of experimental tests of a high-performance TES unit using lithium nitrate trihydrate phase change material as a storage medium. Performance data are presented for complete dual-mode cycles consisting of extraction (melting) followed by charging (freezing). These tests simulate the cyclic operation of a TES unit for asynchronous cooling in a variety of applications. The model analysis is found to agree reasonably well, within 10%, with the experimental data except for conditions very near the initiation of freezing, a consequence of subcooling that is required to initiate solidification.
Evaluating the Effect of Vane Trailing Edge Flow on Turbine Rim Sealing
Authors: Monge-Concepción Iván , Berdanier Reid A. , Barringer Michael D. , Thole Karen A. , Robak Christopher 
Published: June 2020

Abstract
Modern gas turbine development continues to move toward increased overall efficiency, driven in part by higher firing temperatures that point to a need for more cooling air to prevent catastrophic component failure. However, using additional cooling flow bled from the upstream compressor causes a corresponding detriment to overall efficiency. A primary candidate for cooling flow optimization is purge flow, which contributes to sealing the stator–rotor cavity and prevents ingestion of hot main gas path (MGP) flow into the wheelspace. Previous research has identified that the external main gas path flow physics play a significant role in driving rim seal ingestion. However, the potential impact of other cooling flow features on ingestion behavior, such as vane trailing edge (VTE) flow, is absent in the open literature. This paper presents experimental measurements of rim cavity cooling effectiveness collected from a one-stage turbine operating at engine-representative Reynolds and Mach numbers. Carbon dioxide (CO2) was used as a tracer gas in both the purge flow and vane trailing edge flow to investigate flow migration into and out of the wheelspace. Results show that the vane trailing edge flow does in fact migrate into the rim seal and that there is a superposition relationship between individual cooling flow contributions. Computational fluid dynamics (CFD) simulations using unsteady Reynolds-averaged Navier–Stokes (URANS) were used to confirm VTE flow ingestion into the rim seal cavity. Radial and circumferential traverse surveys were performed to quantify cooling flow radial migration through the main gas path with and without vane trailing edge flow. The surveys confirmed that vane trailing edge flow is entrained into the wheelspace as purge flow is reduced. Local CO2 measurements also confirmed the presence of VTE flow deep in the wheelspace cavity.
Variations in patterns of care across neonatal units and their associations with outcomes in very preterm infants: the French EPIPAGE-2 cohort study
Authors: Pierrat Veronique , Burguet Antoine , Marchand-Martin Laetitia , Cambonie Gilles , Coquelin Anaëlle , Roze JC , Durox Melanie , Guillois Bernard , Morgan Andrei S , Kaminski Monique 
Published: June 2020

ObjectivesTo describe patterns of care for very preterm (VP) babies across neonatal intensive care units (NICUs) and associations with outcomes.DesignProspective cohort study, EPIPAGE-2.SettingFrance, 2011.Participants53 (NICUs); 2135 VP neonates born at 27 to 31 weeks.Outcome measuresClusters of units, defined by the association of practices in five neonatal care domains – respiratory, cardiovascular, nutrition, pain management and neurodevelopmental care. Mortality at 2 years corrected age (CA) or severe/moderate neuro-motor or sensory disabilities and proportion of children with scores below threshold on the neurodevelopmental Ages and Stages Questionnaire (ASQ).MethodsHierarchical cluster analysis to identify clusters of units. Comparison of outcomes between clusters, after adjustment for potential cofounders.ResultsThree clusters were identified: Cluster 1 with higher proportions of neonates free of mechanical ventilation at 24 hours of life, receiving early enteral feeding, and neurodevelopmental care practices (26 units; n=1118 babies); Cluster 2 with higher levels of patent ductus arteriosus and pain screening (11 units; n=398 babies); Cluster 3 with higher use of respiratory, cardiovascular and pain treatments (16 units; n=619 babies). No difference was observed between clusters for the baseline maternal and babies’ characteristics. No differences in outcomes were observed between Clusters 1 and 3. Compared with Cluster 1, mortality at 2 years CA or severe/moderate neuro-motor or sensory disabilities was lower in Cluster 2 (adjusted OR 0.46, 95% CI 0.25 to 0.84) but with higher proportion of children with an ASQ below threshold (adjusted OR 1.49, 95% CI 1.07 to 2.08).ConclusionIn French NICUs, care practices for VP babies were non-randomly associated. Differences between clusters were poorly explained by unit or population differences, but were associated with mortality and development at 2 years. Better understanding these variations may help to improve outcomes for VPT babies, as it is likely that some of these discrepancies are unwarranted.